diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ec1ef041b206..771cef6e4d0d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,11 +25,15 @@ name: CI
   pull_request:
     branches:
       - "**"
+permissions:
+  contents: read
 defaults:
   run:
     shell: bash
 jobs:
   pr:
+    permissions:
+      actions: write
     name: PR
     env:
       CI_JOB_NAME: "${{ matrix.name }}"
@@ -142,6 +146,8 @@ jobs:
           AWS_SECRET_ACCESS_KEY: "${{ secrets[format('AWS_SECRET_ACCESS_KEY_{0}', env.ARTIFACTS_AWS_ACCESS_KEY_ID)] }}"
         if: "success() && !env.SKIP_JOB && (github.event_name == 'push' || env.DEPLOY == '1' || env.DEPLOY_ALT == '1')"
   auto:
+    permissions:
+      actions: write
     name: auto
     env:
       CI_JOB_NAME: "${{ matrix.name }}"
@@ -291,7 +297,7 @@ jobs:
             os: ubuntu-20.04-xl
           - name: dist-x86_64-apple
             env:
-              SCRIPT: "./x.py dist --host=x86_64-apple-darwin --target=x86_64-apple-darwin"
+              SCRIPT: "./x.py dist bootstrap --include-default-paths --host=x86_64-apple-darwin --target=x86_64-apple-darwin"
               RUST_CONFIGURE_ARGS: "--enable-full-tools --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false"
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               MACOSX_DEPLOYMENT_TARGET: 10.7
@@ -302,7 +308,7 @@ jobs:
             os: macos-latest
           - name: dist-apple-various
             env:
-              SCRIPT: "./x.py dist --host='' --target=aarch64-apple-ios,x86_64-apple-ios,aarch64-apple-ios-sim"
+              SCRIPT: "./x.py dist bootstrap --include-default-paths --host='' --target=aarch64-apple-ios,x86_64-apple-ios,aarch64-apple-ios-sim"
               RUST_CONFIGURE_ARGS: "--enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false"
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               MACOSX_DEPLOYMENT_TARGET: 10.7
@@ -312,7 +318,7 @@ jobs:
             os: macos-latest
           - name: dist-x86_64-apple-alt
             env:
-              SCRIPT: "./x.py dist"
+              SCRIPT: "./x.py dist bootstrap --include-default-paths"
               RUST_CONFIGURE_ARGS: "--enable-extended --enable-profiler --set rust.jemalloc --set llvm.ninja=false"
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               MACOSX_DEPLOYMENT_TARGET: 10.7
@@ -344,7 +350,7 @@ jobs:
             os: macos-latest
           - name: dist-aarch64-apple
             env:
-              SCRIPT: "./x.py dist --stage 2"
+              SCRIPT: "./x.py dist bootstrap --include-default-paths --stage 2"
               RUST_CONFIGURE_ARGS: "--build=x86_64-apple-darwin --host=aarch64-apple-darwin --target=aarch64-apple-darwin --enable-full-tools --enable-sanitizers --enable-profiler --disable-docs --set rust.jemalloc --set llvm.ninja=false"
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               USE_XCODE_CLANG: 1
@@ -418,19 +424,19 @@ jobs:
           - name: dist-x86_64-msvc
             env:
               RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --host=x86_64-pc-windows-msvc --target=x86_64-pc-windows-msvc --enable-full-tools --enable-profiler"
-              SCRIPT: PGO_HOST=x86_64-pc-windows-msvc src/ci/pgo.sh python x.py dist
+              SCRIPT: PGO_HOST=x86_64-pc-windows-msvc src/ci/pgo.sh python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             os: windows-latest-xl
           - name: dist-i686-msvc
             env:
               RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-msvc --host=i686-pc-windows-msvc --target=i686-pc-windows-msvc,i586-pc-windows-msvc --enable-full-tools --enable-profiler"
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             os: windows-latest-xl
           - name: dist-aarch64-msvc
             env:
               RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --host=aarch64-pc-windows-msvc --enable-full-tools --enable-profiler"
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
               WINDOWS_SDK_20348_HACK: 1
             os: windows-latest-xl
@@ -438,13 +444,13 @@ jobs:
             env:
               RUST_CONFIGURE_ARGS: "--build=i686-pc-windows-gnu --enable-full-tools --enable-profiler --set llvm.allow-old-toolchain"
               NO_DOWNLOAD_CI_LLVM: 1
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               CUSTOM_MINGW: 1
               DIST_REQUIRE_ALL_TOOLS: 1
             os: windows-latest-xl
           - name: dist-x86_64-mingw
             env:
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-gnu --enable-full-tools --enable-profiler --set llvm.allow-old-toolchain"
               NO_DOWNLOAD_CI_LLVM: 1
               CUSTOM_MINGW: 1
@@ -453,7 +459,7 @@ jobs:
           - name: dist-x86_64-msvc-alt
             env:
               RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --enable-extended --enable-profiler"
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
             os: windows-latest-xl
     timeout-minutes: 600
     runs-on: "${{ matrix.os }}"
@@ -547,6 +553,8 @@ jobs:
           AWS_SECRET_ACCESS_KEY: "${{ secrets[format('AWS_SECRET_ACCESS_KEY_{0}', env.ARTIFACTS_AWS_ACCESS_KEY_ID)] }}"
         if: "success() && !env.SKIP_JOB && (github.event_name == 'push' || env.DEPLOY == '1' || env.DEPLOY_ALT == '1')"
   try:
+    permissions:
+      actions: write
     name: try
     env:
       CI_JOB_NAME: "${{ matrix.name }}"
diff --git a/.gitignore b/.gitignore
index b16fb6341c2e..37972532b361 100644
--- a/.gitignore
+++ b/.gitignore
@@ -46,6 +46,7 @@ no_llvm_build
 /dist/
 /unicode-downloads
 /target
+/src/bootstrap/target
 /src/tools/x/target
 # Created by default with `src/ci/docker/run.sh`
 /obj/
diff --git a/.gitmodules b/.gitmodules
index bc2dd3977415..c85049378061 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -13,9 +13,6 @@
 [submodule "src/doc/book"]
 	path = src/doc/book
 	url = https://github.com/rust-lang/book.git
-[submodule "src/tools/miri"]
-	path = src/tools/miri
-	url = https://github.com/rust-lang/miri.git
 [submodule "src/doc/rust-by-example"]
 	path = src/doc/rust-by-example
 	url = https://github.com/rust-lang/rust-by-example.git
diff --git a/Cargo.lock b/Cargo.lock
index 002d73be7d1d..16c0b644e4f7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -103,9 +103,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.60"
+version = "1.0.65"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c794e162a5eff65c72ef524dfe393eb923c354e350bb78b9c7383df13f3bc142"
+checksum = "98161a4e3e2184da77bb14f02184cdd111e83bbbcc9979dfee3c44b9a85f5602"
 
 [[package]]
 name = "array_tool"
@@ -209,34 +209,13 @@ dependencies = [
  "typenum",
 ]
 
-[[package]]
-name = "block-buffer"
-version = "0.7.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c0940dc441f31689269e10ac70eb1002a3a1d3ad1390e030043662eb7fe4688b"
-dependencies = [
- "block-padding",
- "byte-tools",
- "byteorder",
- "generic-array 0.12.4",
-]
-
 [[package]]
 name = "block-buffer"
 version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf7fe51849ea569fd452f37822f606a5cabb684dc918707a0193fd4664ff324"
 dependencies = [
- "generic-array 0.14.4",
-]
-
-[[package]]
-name = "block-padding"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fa79dedbb091f449f1f39e53edf88d5dbe95f895dae6135a8d7b881fb5af73f5"
-dependencies = [
- "byte-tools",
+ "generic-array",
 ]
 
 [[package]]
@@ -277,12 +256,6 @@ dependencies = [
  "toml",
 ]
 
-[[package]]
-name = "byte-tools"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e3b5ca7a04898ad4bcd41c90c5285445ff5b791899bb1b0abdd2a2aa791211d7"
-
 [[package]]
 name = "bytecount"
 version = "0.6.2"
@@ -292,12 +265,6 @@ dependencies = [
  "packed_simd_2",
 ]
 
-[[package]]
-name = "byteorder"
-version = "1.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
-
 [[package]]
 name = "bytes"
 version = "1.0.1"
@@ -540,6 +507,10 @@ name = "cfg-if"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+dependencies = [
+ "compiler_builtins",
+ "rustc-std-workspace-core",
+]
 
 [[package]]
 name = "chalk-derive"
@@ -610,9 +581,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "3.2.5"
+version = "3.2.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d53da17d37dba964b9b3ecb5c5a1f193a2762c700e6829201e645b9381c99dc7"
+checksum = "23b71c3ce99b7611011217b366d923f1d0a7e07a92bb2dbf1e84508c673ca3bd"
 dependencies = [
  "atty",
  "bitflags",
@@ -636,9 +607,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "3.2.5"
+version = "3.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c11d40217d16aee8508cc8e5fde8b4ff24639758608e5374e731b53f85749fb9"
+checksum = "ea0c8bce528c4be4da13ea6fead8965e95b6073585a2f05204bd8f4119f82a65"
 dependencies = [
  "heck",
  "proc-macro-error",
@@ -727,6 +698,7 @@ version = "0.1.65"
 dependencies = [
  "arrayvec",
  "if_chain",
+ "itertools",
  "rustc-semver",
 ]
 
@@ -770,9 +742,9 @@ dependencies = [
 
 [[package]]
 name = "combine"
-version = "4.6.3"
+version = "4.6.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "50b727aacc797f9fc28e355d21f34709ac4fc9adecfe470ad07b8f4464f53062"
+checksum = "35ed6e9d84f0b51a7f52daf1c7d71dd136fd7a3f41a8462b8cdb8c78d920fad4"
 dependencies = [
  "bytes",
  "memchr",
@@ -1010,7 +982,7 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a4600d695eb3f6ce1cd44e6e291adceb2cc3ab12f20a33777ecd0bf6eba34e06"
 dependencies = [
- "generic-array 0.14.4",
+ "generic-array",
 ]
 
 [[package]]
@@ -1035,16 +1007,6 @@ dependencies = [
  "quote",
 ]
 
-[[package]]
-name = "ctor"
-version = "0.1.22"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f877be4f7c9f246b183111634f75baa039715e3f46ce860677d3b19a69fb229c"
-dependencies = [
- "quote",
- "syn",
-]
-
 [[package]]
 name = "curl"
 version = "0.4.43"
@@ -1105,22 +1067,13 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
 
-[[package]]
-name = "digest"
-version = "0.8.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f3d0c8c8752312f9713efd397ff63acb9f85585afbf179282e720e7704954dd5"
-dependencies = [
- "generic-array 0.12.4",
-]
-
 [[package]]
 name = "digest"
 version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8cb780dce4f9a8f5c087362b3a4595936b2019e7c8b30f2c3e9a7e94e6ae9837"
 dependencies = [
- "block-buffer 0.10.2",
+ "block-buffer",
  "crypto-common",
 ]
 
@@ -1268,7 +1221,7 @@ dependencies = [
 name = "error_index_generator"
 version = "0.0.0"
 dependencies = [
- "rustdoc",
+ "mdbook",
 ]
 
 [[package]]
@@ -1299,12 +1252,6 @@ dependencies = [
  "once_cell",
 ]
 
-[[package]]
-name = "fake-simd"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
-
 [[package]]
 name = "fallible-iterator"
 version = "0.2.0"
@@ -1419,9 +1366,9 @@ dependencies = [
 
 [[package]]
 name = "fs-err"
-version = "2.5.0"
+version = "2.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bcd1163ae48bda72a20ae26d66a04d3094135cadab911cff418ae5e33f253431"
+checksum = "64db3e262960f0662f43a6366788d5f10f7f244b8f7d7d987f560baf5ded5c50"
 
 [[package]]
 name = "fs_extra"
@@ -1538,15 +1485,6 @@ dependencies = [
  "termcolor",
 ]
 
-[[package]]
-name = "generic-array"
-version = "0.12.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffdf9f34f1447443d37393cc6c2b8313aebddcd96906caf34e54c68d8e57d7bd"
-dependencies = [
- "typenum",
-]
-
 [[package]]
 name = "generic-array"
 version = "0.14.4"
@@ -1681,16 +1619,16 @@ dependencies = [
 
 [[package]]
 name = "handlebars"
-version = "4.1.0"
+version = "4.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72a0ffab8c36d0436114310c7e10b59b3307e650ddfabf6d006028e29a70c6e6"
+checksum = "360d9740069b2f6cbb63ce2dbaa71a20d3185350cbb990d7bebeb9318415eb17"
 dependencies = [
  "log",
  "pest",
  "pest_derive",
- "quick-error 2.0.0",
  "serde",
  "serde_json",
+ "thiserror",
 ]
 
 [[package]]
@@ -1722,12 +1660,13 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.2.0"
+version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ab7905ea95c6d9af62940f9d7dd9596d54c334ae2c15300c482051292d5637f"
+checksum = "ee512640fe35acbfb4bb779db6f0d80704c2cacfa2e39b601ef3e3f47d1ae4c7"
 dependencies = [
  "compiler_builtins",
  "libc",
+ "rustc-std-workspace-alloc",
  "rustc-std-workspace-core",
 ]
 
@@ -1780,7 +1719,7 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
 dependencies = [
- "quick-error 1.2.3",
+ "quick-error",
 ]
 
 [[package]]
@@ -1826,13 +1765,13 @@ dependencies = [
 
 [[package]]
 name = "im-rc"
-version = "15.0.0"
+version = "15.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ca8957e71f04a205cb162508f9326aea04676c8dfd0711220190d6b83664f3f"
+checksum = "af1955a75fa080c677d3972822ec4bad316169ab1cfc6c257a942c2265dbe5fe"
 dependencies = [
  "bitmaps",
- "rand_core 0.5.1",
- "rand_xoshiro 0.4.0",
+ "rand_core 0.6.2",
+ "rand_xoshiro",
  "sized-chunks",
  "typenum",
  "version_check",
@@ -1956,6 +1895,16 @@ dependencies = [
  "shlex",
 ]
 
+[[package]]
+name = "jsondoclint"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "fs-err",
+ "rustdoc-json-types",
+ "serde_json",
+]
+
 [[package]]
 name = "jsonpath_lib"
 version = "0.2.6"
@@ -1999,6 +1948,25 @@ dependencies = [
  "rustc-std-workspace-core",
 ]
 
+[[package]]
+name = "libffi"
+version = "3.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e454b3efb16fba3b17810ae5e41df02b649e564ab3c5a34b3b93ed07ad287e6"
+dependencies = [
+ "libc",
+ "libffi-sys",
+]
+
+[[package]]
+name = "libffi-sys"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab4106b7f09d7b87d021334d5618fac1dfcfb824d4c5fe111ff0074dfd242e15"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "libgit2-sys"
 version = "0.14.0+1.5.0"
@@ -2169,7 +2137,7 @@ version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6a38fc55c8bbc10058782919516f88826e70320db6d206aebc49611d24216ae"
 dependencies = [
- "digest 0.10.2",
+ "digest",
 ]
 
 [[package]]
@@ -2293,6 +2261,8 @@ dependencies = [
  "getrandom 0.2.0",
  "lazy_static",
  "libc",
+ "libffi",
+ "libloading",
  "log",
  "measureme",
  "rand 0.8.5",
@@ -2395,12 +2365,6 @@ version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7709cef83f0c1f58f666e746a08b21e0085f7440fa6a29cc194d68aac97a4225"
 
-[[package]]
-name = "opaque-debug"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2839e79665f131bdb5782e51f2c6c9599c133c6098982a54c794358bf432529c"
-
 [[package]]
 name = "opener"
 version = "0.5.0"
@@ -2471,15 +2435,6 @@ version = "6.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8e22443d1643a904602595ba1cd8f7d896afe56d26712531c5ff73a15b2fbf64"
 
-[[package]]
-name = "output_vt100"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "628223faebab4e3e40667ee0b2336d34a5b960ff60ea743ddfdbcf7770bcfb66"
-dependencies = [
- "winapi",
-]
-
 [[package]]
 name = "owo-colors"
 version = "3.4.0"
@@ -2590,18 +2545,19 @@ dependencies = [
 
 [[package]]
 name = "pest"
-version = "2.1.3"
+version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10f4872ae94d7b90ae48754df22fd42ad52ce740b8f370b03da4835417403e53"
+checksum = "4b0560d531d1febc25a3c9398a62a71256c0178f2e3443baedd9ad4bb8c9deb4"
 dependencies = [
+ "thiserror",
  "ucd-trie",
 ]
 
 [[package]]
 name = "pest_derive"
-version = "2.1.0"
+version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "833d1ae558dc601e9a60366421196a8d94bc0ac980476d0b67e1d0988d72b2d0"
+checksum = "905708f7f674518498c1f8d644481440f476d39ca6ecae83319bba7c6c12da91"
 dependencies = [
  "pest",
  "pest_generator",
@@ -2609,9 +2565,9 @@ dependencies = [
 
 [[package]]
 name = "pest_generator"
-version = "2.1.3"
+version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99b8db626e31e5b81787b9783425769681b347011cc59471e33ea46d2ea0cf55"
+checksum = "5803d8284a629cc999094ecd630f55e91b561a1d1ba75e233b00ae13b91a69ad"
 dependencies = [
  "pest",
  "pest_meta",
@@ -2622,13 +2578,13 @@ dependencies = [
 
 [[package]]
 name = "pest_meta"
-version = "2.1.3"
+version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54be6e404f5317079812fc8f9f5279de376d8856929e21c184ecf6bbd692a11d"
+checksum = "1538eb784f07615c6d9a8ab061089c6c54a344c5b4301db51990ca1c241e8c04"
 dependencies = [
- "maplit",
+ "once_cell",
  "pest",
- "sha-1 0.8.2",
+ "sha-1",
 ]
 
 [[package]]
@@ -2720,18 +2676,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
 
-[[package]]
-name = "pretty_assertions"
-version = "1.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c89f989ac94207d048d92db058e4f6ec7342b0971fc58d1271ca148b799b3563"
-dependencies = [
- "ansi_term",
- "ctor",
- "diff",
- "output_vt100",
-]
-
 [[package]]
 name = "pretty_env_logger"
 version = "0.4.0"
@@ -2830,12 +2774,6 @@ version = "1.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
 
-[[package]]
-name = "quick-error"
-version = "2.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ac73b1112776fc109b2e61909bc46c7e1bf0d7f690ffb1676553acce16d5cda"
-
 [[package]]
 name = "quine-mc_cluskey"
 version = "0.2.4"
@@ -2931,15 +2869,6 @@ dependencies = [
  "rand_core 0.5.1",
 ]
 
-[[package]]
-name = "rand_xoshiro"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a9fcdd2e881d02f1d9390ae47ad8e5696a9e4be7b547a1da2afbc61973217004"
-dependencies = [
- "rand_core 0.5.1",
-]
-
 [[package]]
 name = "rand_xoshiro"
 version = "0.6.0"
@@ -3172,7 +3101,6 @@ dependencies = [
  "bstr",
  "clap",
  "libz-sys",
- "memchr",
  "regex",
  "serde_json",
  "syn",
@@ -3207,6 +3135,7 @@ dependencies = [
  "rustc_serialize",
  "rustc_span",
  "smallvec",
+ "thin-vec",
  "tracing",
 ]
 
@@ -3228,6 +3157,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "smallvec",
+ "thin-vec",
  "tracing",
 ]
 
@@ -3322,6 +3252,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "smallvec",
+ "thin-vec",
  "tracing",
 ]
 
@@ -3332,7 +3263,6 @@ dependencies = [
  "bitflags",
  "cstr",
  "libc",
- "libloading",
  "measureme",
  "object 0.29.0",
  "rustc-demangle",
@@ -3446,6 +3376,7 @@ dependencies = [
  "stable_deref_trait",
  "stacker",
  "tempfile",
+ "thin-vec",
  "tracing",
  "winapi",
 ]
@@ -3514,6 +3445,7 @@ dependencies = [
  "rustc_macros",
  "rustc_serialize",
  "rustc_span",
+ "rustc_target",
  "serde",
  "serde_json",
  "termcolor",
@@ -3807,7 +3739,7 @@ dependencies = [
  "gsgdt",
  "polonius-engine",
  "rand 0.8.5",
- "rand_xoshiro 0.6.0",
+ "rand_xoshiro",
  "rustc-rayon",
  "rustc-rayon-core",
  "rustc_apfloat",
@@ -3828,6 +3760,7 @@ dependencies = [
  "rustc_target",
  "rustc_type_ir",
  "smallvec",
+ "thin-vec",
  "tracing",
 ]
 
@@ -4017,6 +3950,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
+ "thin-vec",
  "tracing",
 ]
 
@@ -4038,7 +3972,9 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
+ "rustc_type_ir",
  "smallvec",
+ "thin-vec",
  "tracing",
 ]
 
@@ -4094,6 +4030,7 @@ dependencies = [
  "indexmap",
  "rustc_macros",
  "smallvec",
+ "thin-vec",
 ]
 
 [[package]]
@@ -4142,7 +4079,7 @@ dependencies = [
  "rustc_macros",
  "rustc_serialize",
  "scoped-tls",
- "sha-1 0.10.0",
+ "sha-1",
  "sha2",
  "tracing",
  "unicode-width",
@@ -4172,6 +4109,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags",
  "rustc_data_structures",
+ "rustc_feature",
  "rustc_index",
  "rustc_macros",
  "rustc_serialize",
@@ -4234,6 +4172,7 @@ version = "0.1.0"
 dependencies = [
  "itertools",
  "rustc_data_structures",
+ "rustc_hir",
  "rustc_infer",
  "rustc_macros",
  "rustc_middle",
@@ -4330,6 +4269,7 @@ dependencies = [
  "serde_json",
  "smallvec",
  "tempfile",
+ "thin-vec",
  "tracing",
  "tracing-subscriber",
  "tracing-tree",
@@ -4519,9 +4459,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.83"
+version = "1.0.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38dd04e3c8279e75b31ef29dbdceebfe5ad89f4d0937213c53f7d49d01b3d5a7"
+checksum = "e55a28e3aaef9d5ce0506d0a14dbba8054ddc7e499ef522dd8b26859ec9d4a44"
 dependencies = [
  "indexmap",
  "itoa",
@@ -4529,18 +4469,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "sha-1"
-version = "0.8.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7d94d0bede923b3cea61f3f1ff57ff8cdfd77b400fb8f9998949e0cf04163df"
-dependencies = [
- "block-buffer 0.7.3",
- "digest 0.8.1",
- "fake-simd",
- "opaque-debug",
-]
-
 [[package]]
 name = "sha-1"
 version = "0.10.0"
@@ -4549,7 +4477,7 @@ checksum = "028f48d513f9678cda28f6e4064755b3fbb2af6acd672f2c209b62323f7aea0f"
 dependencies = [
  "cfg-if 1.0.0",
  "cpufeatures",
- "digest 0.10.2",
+ "digest",
 ]
 
 [[package]]
@@ -4560,7 +4488,7 @@ checksum = "99c3bd8169c58782adad9290a9af5939994036b76187f7b4f0e6de91dbbfc0ec"
 dependencies = [
  "cfg-if 1.0.0",
  "cpufeatures",
- "digest 0.10.2",
+ "digest",
 ]
 
 [[package]]
@@ -4689,13 +4617,13 @@ version = "0.0.0"
 dependencies = [
  "addr2line 0.16.0",
  "alloc",
- "cfg-if 0.1.10",
+ "cfg-if 1.0.0",
  "compiler_builtins",
  "core",
  "dlmalloc",
  "fortanix-sgx-abi",
  "hashbrown",
- "hermit-abi 0.2.0",
+ "hermit-abi 0.2.6",
  "libc",
  "miniz_oxide 0.4.0",
  "object 0.26.2",
@@ -4713,7 +4641,7 @@ dependencies = [
 name = "std_detect"
 version = "0.1.5"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if 1.0.0",
  "compiler_builtins",
  "libc",
  "rustc-std-workspace-alloc",
@@ -4884,19 +4812,25 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b1141d4d61095b28419e22cb0bbf02755f5e54e0526f97f1e3d1d160e60885fb"
 
 [[package]]
-name = "thiserror"
-version = "1.0.30"
+name = "thin-vec"
+version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "854babe52e4df1653706b98fcfc05843010039b406875930a70e4d9644e5c417"
+checksum = "104c2cb3180b6fb6d5b2278768e9b88b578d32ba751ea6e8d026688a40d7ed87"
+
+[[package]]
+name = "thiserror"
+version = "1.0.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d0a539a918745651435ac7db7a18761589a94cd7e94cd56999f828bf73c8a57"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.30"
+version = "1.0.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa32fd3f627f367fe16f893e2597ae3c05020f8bba2666a4e6ea73d377e5714b"
+checksum = "c251e90f708e16c49a16f4917dc2131e75222b72edfa9cb7f7c58ae56aae0c09"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -4956,9 +4890,18 @@ checksum = "29738eedb4388d9ea620eeab9384884fc3f06f586a2eddb56bedc5885126c7c1"
 
 [[package]]
 name = "tinyvec"
-version = "0.3.4"
+version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "238ce071d267c5710f9d31451efec16c5ee22de34df17cc05e56cbc92e967117"
+checksum = "87cc5ceb3875bb20c2890005a4e226a4651264a5c75edb2421b52861a0a0cb50"
+dependencies = [
+ "tinyvec_macros",
+]
+
+[[package]]
+name = "tinyvec_macros"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cda74da7e1a664f795bb1f8a87ec406fb89a02522cf6e50620d016add6dbbf5c"
 
 [[package]]
 name = "tokio"
@@ -5119,14 +5062,16 @@ checksum = "56dee185309b50d1f11bfedef0fe6d036842e3fb77413abef29f8f8d1c5d4c1c"
 
 [[package]]
 name = "ui_test"
-version = "0.1.0"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d1f546a5883ae78da735bba529ec1116661e2f73582f23920d994dc97da3a22"
 dependencies = [
  "cargo_metadata 0.15.0",
  "color-eyre",
  "colored",
  "crossbeam",
+ "diff",
  "lazy_static",
- "pretty_assertions",
  "regex",
  "rustc_version",
  "serde",
@@ -5244,24 +5189,24 @@ dependencies = [
 
 [[package]]
 name = "unicode-normalization"
-version = "0.1.13"
+version = "0.1.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6fb19cf769fa8c6a80a162df694621ebeb4dafb606470b2b2fce0be40a98a977"
+checksum = "5c5713f0fc4b5db668a2ac63cdb7bb4469d8c9fed047b1d0292cc7b0ce2ba921"
 dependencies = [
  "tinyvec",
 ]
 
 [[package]]
 name = "unicode-script"
-version = "0.5.3"
+version = "0.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "098ec66172ce21cd55f8bcc786ee209dd20e04eff70acfca30cb79924d173ae9"
+checksum = "7d817255e1bed6dfd4ca47258685d14d2bdcfbc64fdc9e3819bd5848057b8ecc"
 
 [[package]]
 name = "unicode-security"
-version = "0.0.5"
+version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d87c28edc5b263377e448d6cdcb935c06b95413d8013ba6fae470558ccab18f"
+checksum = "9ef5756b3097992b934b06608c69f48448a0fbe804bb1e72b982f6d7983e9e63"
 dependencies = [
  "unicode-normalization",
  "unicode-script",
@@ -5269,15 +5214,15 @@ dependencies = [
 
 [[package]]
 name = "unicode-segmentation"
-version = "1.9.0"
+version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7e8820f5d777f6224dc4be3632222971ac30164d4a258d595640799554ebfd99"
+checksum = "0fdbf052a0783de01e944a6ce7a8cb939e295b1e7be835a1112c3b9a7f047a5a"
 
 [[package]]
 name = "unicode-width"
-version = "0.1.8"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
+checksum = "c0edd1e5b14653f783770bce4a4dabb4a5108a5370a5f5d8cfe8710c361f6c8b"
 dependencies = [
  "compiler_builtins",
  "rustc-std-workspace-core",
@@ -5286,9 +5231,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.2"
+version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
+checksum = "f962df74c8c05a667b5ee8bcf162993134c104e96440b663c8daa176dc772d8c"
 
 [[package]]
 name = "unicode_categories"
diff --git a/Cargo.toml b/Cargo.toml
index 5753730053f4..e49fe5e2f635 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,6 +33,7 @@ members = [
   "src/tools/unicode-table-generator",
   "src/tools/expand-yaml-anchors",
   "src/tools/jsondocck",
+  "src/tools/jsondoclint",
   "src/tools/html-checker",
   "src/tools/bump-stage0",
   "src/tools/replace-version-placeholder",
diff --git a/README.md b/README.md
index 7c229487d1c1..27e7145c5a99 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ Read ["Installation"] from [The Book].
 ## Installing from Source
 
 The Rust build system uses a Python script called `x.py` to build the compiler,
-which manages the bootstrapping process. It lives in the root of the project.
+which manages the bootstrapping process. It lives at the root of the project.
 
 The `x.py` command can be run directly on most systems in the following format:
 
@@ -32,7 +32,7 @@ The `x.py` command can be run directly on most systems in the following format:
 
 This is how the documentation and examples assume you are running `x.py`.
 
-Systems such as Ubuntu 20.04 LTS do not create the necessary `python` command by default when Python is installed that allows `x.py` to be run directly. In that case you can either create a symlink for `python` (Ubuntu provides the `python-is-python3` package for this), or run `x.py` using Python itself:
+Systems such as Ubuntu 20.04 LTS do not create the necessary `python` command by default when Python is installed that allows `x.py` to be run directly. In that case, you can either create a symlink for `python` (Ubuntu provides the `python-is-python3` package for this), or run `x.py` using Python itself:
 
 ```sh
 # Python 3
@@ -103,11 +103,10 @@ by running it with the `--help` flag or reading the [rustc dev guide][rustcguide
 ### Building on Windows
 
 There are two prominent ABIs in use on Windows: the native (MSVC) ABI used by
-Visual Studio, and the GNU ABI used by the GCC toolchain. Which version of Rust
-you need depends largely on what C/C++ libraries you want to interoperate with:
-for interop with software produced by Visual Studio use the MSVC build of Rust;
-for interop with GNU software built using the MinGW/MSYS2 toolchain use the GNU
-build.
+Visual Studio and the GNU ABI used by the GCC toolchain. Which version of Rust
+you need depends largely on what C/C++ libraries you want to interoperate with.
+Use the MSVC build of Rust to interop with software produced by Visual Studio and
+the GNU build to interop with GNU software built using the MinGW/MSYS2 toolchain.
 
 #### MinGW
 
@@ -115,10 +114,10 @@ build.
 
 [msys2]: https://www.msys2.org/
 
-1. Grab the latest [MSYS2 installer][msys2] and go through the installer.
+1. Download the latest [MSYS2 installer][msys2] and go through the installer.
 
-2. Run `mingw32_shell.bat` or `mingw64_shell.bat` from wherever you installed
-   MSYS2 (i.e. `C:\msys64`), depending on whether you want 32-bit or 64-bit
+2. Run `mingw32_shell.bat` or `mingw64_shell.bat` from the MSYS2 installation
+   directory (e.g. `C:\msys64`), depending on whether you want 32-bit or 64-bit
    Rust. (As of the latest version of MSYS2 you have to run `msys2_shell.cmd
    -mingw32` or `msys2_shell.cmd -mingw64` from the command line instead)
 
@@ -168,7 +167,7 @@ shell with:
 python x.py build
 ```
 
-Currently, building Rust only works with some known versions of Visual Studio. If
+Right now, building Rust only works with some known versions of Visual Studio. If
 you have a more recent version installed and the build system doesn't understand,
 you may need to force rustbuild to use an older version. This can be done
 by manually calling the appropriate vcvars file before running the bootstrap.
@@ -225,7 +224,7 @@ the ABI used. I.e., if the ABI was `x86_64-pc-windows-msvc`, the directory will
 
 Since the Rust compiler is written in Rust, it must be built by a
 precompiled "snapshot" version of itself (made in an earlier stage of
-development). As such, source builds require a connection to the Internet, to
+development). As such, source builds require an Internet connection to
 fetch snapshots, and an OS that can execute the available snapshot binaries.
 
 Snapshot binaries are currently built and tested on several platforms:
diff --git a/RELEASES.md b/RELEASES.md
index 147ff3561a30..694bd09658f7 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -1,3 +1,144 @@
+Version 1.64.0 (2022-09-22)
+===========================
+
+Language
+--------
+- [Unions with mutable references or tuples of allowed types are now allowed](https://github.com/rust-lang/rust/pull/97995/)
+- It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](https://github.com/rust-lang/rust/pull/98017/)
+- Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`](https://github.com/rust-lang/rust/pull/95977/), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future.
+
+Compiler
+--------
+- [Add Nintendo Switch as tier 3 target](https://github.com/rust-lang/rust/pull/88991/)
+  - Refer to Rust's [platform support page][platform-support-doc] for more
+    information on Rust's tiered platform support.
+- [Only compile `#[used]` as llvm.compiler.used for ELF targets](https://github.com/rust-lang/rust/pull/93718/)
+- [Add the `--diagnostic-width` compiler flag to define the terminal width.](https://github.com/rust-lang/rust/pull/95635/)
+- [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS](https://github.com/rust-lang/rust/pull/98771/)
+
+Libraries
+---------
+- [Remove restrictions on compare-exchange memory ordering.](https://github.com/rust-lang/rust/pull/98383/)
+- You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](https://github.com/rust-lang/rust/pull/97915/)
+- [Make RwLockReadGuard covariant](https://github.com/rust-lang/rust/pull/96820/)
+- [Implement `FusedIterator` for `std::net::[Into]Incoming`](https://github.com/rust-lang/rust/pull/97300/)
+- [`impl<T: AsRawFd> AsRawFd for {Arc,Box}<T>`](https://github.com/rust-lang/rust/pull/97437/)
+- [`ptr::copy` and `ptr::swap` are doing untyped copies](https://github.com/rust-lang/rust/pull/97712/)
+- [Add cgroupv1 support to `available_parallelism`](https://github.com/rust-lang/rust/pull/97925/)
+- [Mitigate many incorrect uses of `mem::uninitialized`](https://github.com/rust-lang/rust/pull/99182/)
+
+Stabilized APIs
+---------------
+
+- [`future::IntoFuture`](https://doc.rust-lang.org/stable/std/future/trait.IntoFuture.html)
+- [`future::poll_fn`](https://doc.rust-lang.org/stable/std/future/fn.poll_fn.html)
+- [`task::ready!`](https://doc.rust-lang.org/stable/std/task/macro.ready.html)
+- [`num::NonZero*::checked_mul`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_mul)
+- [`num::NonZero*::checked_pow`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_pow)
+- [`num::NonZero*::saturating_mul`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_mul)
+- [`num::NonZero*::saturating_pow`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_pow)
+- [`num::NonZeroI*::abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.abs)
+- [`num::NonZeroI*::checked_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.checked_abs)
+- [`num::NonZeroI*::overflowing_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.overflowing_abs)
+- [`num::NonZeroI*::saturating_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.saturating_abs)
+- [`num::NonZeroI*::unsigned_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.unsigned_abs)
+- [`num::NonZeroI*::wrapping_abs`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.wrapping_abs)
+- [`num::NonZeroU*::checked_add`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_add)
+- [`num::NonZeroU*::checked_next_power_of_two`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_next_power_of_two)
+- [`num::NonZeroU*::saturating_add`](https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_add)
+- [`os::unix::process::CommandExt::process_group`](https://doc.rust-lang.org/stable/std/os/unix/process/trait.CommandExt.html#tymethod.process_group)
+- [`os::windows::fs::FileTypeExt::is_symlink_dir`](https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_dir)
+- [`os::windows::fs::FileTypeExt::is_symlink_file`](https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_file)
+
+These types were previously stable in `std::ffi`, but are now also available in `core` and `alloc`:
+
+- [`core::ffi::CStr`](https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html)
+- [`core::ffi::FromBytesWithNulError`](https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesWithNulError.html)
+- [`alloc::ffi::CString`](https://doc.rust-lang.org/stable/alloc/ffi/struct.CString.html)
+- [`alloc::ffi::FromVecWithNulError`](https://doc.rust-lang.org/stable/alloc/ffi/struct.FromVecWithNulError.html)
+- [`alloc::ffi::IntoStringError`](https://doc.rust-lang.org/stable/alloc/ffi/struct.IntoStringError.html)
+- [`alloc::ffi::NulError`](https://doc.rust-lang.org/stable/alloc/ffi/struct.NulError.html)
+
+These types were previously stable in `std::os::raw`, but are now also available in `core::ffi` and `std::ffi`:
+
+- [`ffi::c_char`](https://doc.rust-lang.org/stable/std/ffi/type.c_char.html)
+- [`ffi::c_double`](https://doc.rust-lang.org/stable/std/ffi/type.c_double.html)
+- [`ffi::c_float`](https://doc.rust-lang.org/stable/std/ffi/type.c_float.html)
+- [`ffi::c_int`](https://doc.rust-lang.org/stable/std/ffi/type.c_int.html)
+- [`ffi::c_long`](https://doc.rust-lang.org/stable/std/ffi/type.c_long.html)
+- [`ffi::c_longlong`](https://doc.rust-lang.org/stable/std/ffi/type.c_longlong.html)
+- [`ffi::c_schar`](https://doc.rust-lang.org/stable/std/ffi/type.c_schar.html)
+- [`ffi::c_short`](https://doc.rust-lang.org/stable/std/ffi/type.c_short.html)
+- [`ffi::c_uchar`](https://doc.rust-lang.org/stable/std/ffi/type.c_uchar.html)
+- [`ffi::c_uint`](https://doc.rust-lang.org/stable/std/ffi/type.c_uint.html)
+- [`ffi::c_ulong`](https://doc.rust-lang.org/stable/std/ffi/type.c_ulong.html)
+- [`ffi::c_ulonglong`](https://doc.rust-lang.org/stable/std/ffi/type.c_ulonglong.html)
+- [`ffi::c_ushort`](https://doc.rust-lang.org/stable/std/ffi/type.c_ushort.html)
+
+These APIs are now usable in const contexts:
+
+- [`slice::from_raw_parts`](https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts.html)
+
+Cargo
+-----
+- [Packages can now inherit settings from the workspace so that the settings
+  can be centralized in one place.](https://github.com/rust-lang/cargo/pull/10859) See
+  [`workspace.package`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacepackage-table)
+  and
+  [`workspace.dependencies`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacedependencies-table)
+  for more details on how to define these common settings.
+- [Cargo commands can now accept multiple `--target` flags to build for
+  multiple targets at once](https://github.com/rust-lang/cargo/pull/10766), and the
+  [`build.target`](https://doc.rust-lang.org/nightly/cargo/reference/config.html#buildtarget)
+  config option may now take an array of multiple targets.
+- [The `--jobs` argument can now take a negative number to count backwards from
+  the max CPUs.](https://github.com/rust-lang/cargo/pull/10844)
+- [`cargo add` will now update `Cargo.lock`.](https://github.com/rust-lang/cargo/pull/10902)
+- [Added](https://github.com/rust-lang/cargo/pull/10838) the
+  [`--crate-type`](https://doc.rust-lang.org/nightly/cargo/commands/cargo-rustc.html#option-cargo-rustc---crate-type)
+  flag to `cargo rustc` to override the crate type.
+- [Significantly improved the performance fetching git dependencies from GitHub
+  when using a hash in the `rev` field.](https://github.com/rust-lang/cargo/pull/10079)
+
+Misc
+----
+- [The `rust-analyzer` rustup component is now available on the stable channel.](https://github.com/rust-lang/rust/pull/98640/)
+
+Compatibility Notes
+-------------------
+- The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](https://github.com/rust-lang/rust/pull/95026/)
+- [Network primitives are now implemented with the ideal Rust layout, not the C system layout](https://github.com/rust-lang/rust/pull/78802/). This can cause problems when transmuting the types.
+- [Add assertion that `transmute_copy`'s `U` is not larger than `T`](https://github.com/rust-lang/rust/pull/98839/)
+- [A soundness bug in `BTreeMap` was fixed](https://github.com/rust-lang/rust/pull/99413/) that allowed data it was borrowing to be dropped before the container.
+- [The Drop behavior of C-like enums cast to ints has changed](https://github.com/rust-lang/rust/pull/96862/). These are already discouraged by a compiler warning.
+- [Relate late-bound closure lifetimes to parent fn in NLL](https://github.com/rust-lang/rust/pull/98835/)
+- [Errors at const-eval time are now in future incompatibility reports](https://github.com/rust-lang/rust/pull/97743/)
+- On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted](https://github.com/rust-lang/rust/pull/99155/).
+- [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`](https://github.com/rust-lang/rust/pull/97346/), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed.
+
+Internal Changes
+----------------
+
+These changes do not affect any public interfaces of Rust, but they represent
+significant improvements to the performance or internals of rustc and related
+tools.
+
+- Windows builds now use profile-guided optimization, providing 10-20% improvements to compiler performance: [Utilize PGO for windows x64 rustc dist builds](https://github.com/rust-lang/rust/pull/96978/)
+- [Stop keeping metadata in memory before writing it to disk](https://github.com/rust-lang/rust/pull/96544/)
+- [compiletest: strip debuginfo by default for mode=ui](https://github.com/rust-lang/rust/pull/98140/)
+- Many improvements to generated code for derives, including performance improvements:
+  - [Don't use match-destructuring for derived ops on structs.](https://github.com/rust-lang/rust/pull/98446/)
+  - [Many small deriving cleanups](https://github.com/rust-lang/rust/pull/98741/)
+  - [More derive output improvements](https://github.com/rust-lang/rust/pull/98758/)
+  - [Clarify deriving code](https://github.com/rust-lang/rust/pull/98915/)
+  - [Final derive output improvements](https://github.com/rust-lang/rust/pull/99046/)
+  - [Stop injecting `#[allow(unused_qualifications)]` in generated `derive` implementations](https://github.com/rust-lang/rust/pull/99485/)
+  - [Improve `derive(Debug)`](https://github.com/rust-lang/rust/pull/98190/)
+- [Bump to clap 3](https://github.com/rust-lang/rust/pull/98213/)
+- [fully move dropck to mir](https://github.com/rust-lang/rust/pull/98641/)
+- [Optimize `Vec::insert` for the case where `index == len`.](https://github.com/rust-lang/rust/pull/98755/)
+- [Convert rust-analyzer to an in-tree tool](https://github.com/rust-lang/rust/pull/99603/)
+
 Version 1.63.0 (2022-08-11)
 ==========================
 
@@ -217,6 +358,7 @@ Language
 - [Fix constants not getting dropped if part of a diverging expression][94775]
 - [Support unit struct/enum variant in destructuring assignment][95380]
 - [Remove mutable_borrow_reservation_conflict lint and allow the code pattern][96268]
+- [`const` functions may now specify `extern "C"` or `extern "Rust"`][95346]
 
 Compiler
 --------
@@ -306,6 +448,7 @@ and related tools.
 [94872]: https://github.com/rust-lang/rust/pull/94872/
 [95006]: https://github.com/rust-lang/rust/pull/95006/
 [95035]: https://github.com/rust-lang/rust/pull/95035/
+[95346]: https://github.com/rust-lang/rust/pull/95346/
 [95372]: https://github.com/rust-lang/rust/pull/95372/
 [95380]: https://github.com/rust-lang/rust/pull/95380/
 [95431]: https://github.com/rust-lang/rust/pull/95431/
@@ -1442,7 +1585,7 @@ Compatibility Notes
 - [Mixing Option and Result via `?` is no longer permitted in closures for inferred types.][86831]
 - [Previously unsound code is no longer permitted where different constructors in branches
   could require different lifetimes.][85574]
-- As previously mentioned the [`std::arch` instrinsics now uses stricter const checking][83278]
+- As previously mentioned the [`std::arch` intrinsics now uses stricter const checking][83278]
   than before and may reject some previously accepted code.
 - [`i128` multiplication on Cortex M0+ platforms currently unconditionally causes overflow
    when compiled with `codegen-units = 1`.][86063]
@@ -2520,7 +2663,7 @@ Compatibility Notes
 - [Fixed a regression parsing `{} && false` in tail expressions.][74650]
 - [Added changes to how proc-macros are expanded in `macro_rules!` that should
   help to preserve more span information.][73084] These changes may cause
-  compiliation errors if your macro was unhygenic or didn't correctly handle
+  compilation errors if your macro was unhygenic or didn't correctly handle
   `Delimiter::None`.
 - [Moved support for the CloudABI target to tier 3.][75568]
 - [`linux-gnu` targets now require minimum kernel 2.6.32 and glibc 2.11.][74163]
diff --git a/compiler/rustc_ast/Cargo.toml b/compiler/rustc_ast/Cargo.toml
index 9822e9864e21..c24180bacfc1 100644
--- a/compiler/rustc_ast/Cargo.toml
+++ b/compiler/rustc_ast/Cargo.toml
@@ -7,12 +7,13 @@ edition = "2021"
 doctest = false
 
 [dependencies]
-rustc_serialize = { path = "../rustc_serialize" }
-tracing = "0.1"
-rustc_span = { path = "../rustc_span" }
+bitflags = "1.2.1"
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_index = { path = "../rustc_index" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_macros = { path = "../rustc_macros" }
+rustc_serialize = { path = "../rustc_serialize" }
+rustc_span = { path = "../rustc_span" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
-bitflags = "1.2.1"
+thin-vec = "0.2.8"
+tracing = "0.1"
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index fb521073a428..0efde1e7b212 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -24,22 +24,19 @@ pub use UnsafeSource::*;
 
 use crate::ptr::P;
 use crate::token::{self, CommentKind, Delimiter};
-use crate::tokenstream::{DelimSpan, LazyTokenStream, TokenStream};
-
+use crate::tokenstream::{DelimSpan, LazyAttrTokenStream, TokenStream};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::sync::Lrc;
-use rustc_data_structures::thin_vec::ThinVec;
 use rustc_macros::HashStable_Generic;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-
-use std::cmp::Ordering;
 use std::convert::TryFrom;
 use std::fmt;
 use std::mem;
+use thin_vec::ThinVec;
 
 /// A "Label" is an identifier of some point in sources,
 /// e.g. in the following code:
@@ -94,7 +91,7 @@ pub struct Path {
     /// The segments in the path: the things separated by `::`.
     /// Global paths begin with `kw::PathRoot`.
     pub segments: Vec<PathSegment>,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 impl PartialEq<Symbol> for Path {
@@ -326,46 +323,17 @@ pub type GenericBounds = Vec<GenericBound>;
 /// Specifies the enforced ordering for generic parameters. In the future,
 /// if we wanted to relax this order, we could override `PartialEq` and
 /// `PartialOrd`, to allow the kinds to be unordered.
-#[derive(Hash, Clone, Copy)]
+#[derive(Hash, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum ParamKindOrd {
     Lifetime,
-    Type,
-    Const,
-    // `Infer` is not actually constructed directly from the AST, but is implicitly constructed
-    // during HIR lowering, and `ParamKindOrd` will implicitly order inferred variables last.
-    Infer,
+    TypeOrConst,
 }
 
-impl Ord for ParamKindOrd {
-    fn cmp(&self, other: &Self) -> Ordering {
-        use ParamKindOrd::*;
-        let to_int = |v| match v {
-            Lifetime => 0,
-            Infer | Type | Const => 1,
-        };
-
-        to_int(*self).cmp(&to_int(*other))
-    }
-}
-impl PartialOrd for ParamKindOrd {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-impl PartialEq for ParamKindOrd {
-    fn eq(&self, other: &Self) -> bool {
-        self.cmp(other) == Ordering::Equal
-    }
-}
-impl Eq for ParamKindOrd {}
-
 impl fmt::Display for ParamKindOrd {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             ParamKindOrd::Lifetime => "lifetime".fmt(f),
-            ParamKindOrd::Type => "type".fmt(f),
-            ParamKindOrd::Const { .. } => "const".fmt(f),
-            ParamKindOrd::Infer => "infer".fmt(f),
+            ParamKindOrd::TypeOrConst => "type and const".fmt(f),
         }
     }
 }
@@ -566,7 +534,7 @@ pub struct Block {
     /// Distinguishes between `unsafe { ... }` and `{ ... }`.
     pub rules: BlockCheckMode,
     pub span: Span,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
     /// The following *isn't* a parse error, but will cause multiple errors in following stages.
     /// ```compile_fail
     /// let x = {
@@ -585,7 +553,7 @@ pub struct Pat {
     pub id: NodeId,
     pub kind: PatKind,
     pub span: Span,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 impl Pat {
@@ -596,7 +564,7 @@ impl Pat {
             // In a type expression `_` is an inference variable.
             PatKind::Wild => TyKind::Infer,
             // An IDENT pattern with no binding mode would be valid as path to a type. E.g. `u32`.
-            PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
+            PatKind::Ident(BindingAnnotation::NONE, ident, None) => {
                 TyKind::Path(None, Path::from_ident(*ident))
             }
             PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
@@ -683,10 +651,43 @@ pub struct PatField {
     pub is_placeholder: bool,
 }
 
-#[derive(Clone, PartialEq, Encodable, Decodable, Debug, Copy)]
-pub enum BindingMode {
-    ByRef(Mutability),
-    ByValue(Mutability),
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
+pub enum ByRef {
+    Yes,
+    No,
+}
+
+impl From<bool> for ByRef {
+    fn from(b: bool) -> ByRef {
+        match b {
+            false => ByRef::No,
+            true => ByRef::Yes,
+        }
+    }
+}
+
+/// Explicit binding annotations given in the HIR for a binding. Note
+/// that this is not the final binding *mode* that we infer after type
+/// inference.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
+pub struct BindingAnnotation(pub ByRef, pub Mutability);
+
+impl BindingAnnotation {
+    pub const NONE: Self = Self(ByRef::No, Mutability::Not);
+    pub const REF: Self = Self(ByRef::Yes, Mutability::Not);
+    pub const MUT: Self = Self(ByRef::No, Mutability::Mut);
+    pub const REF_MUT: Self = Self(ByRef::Yes, Mutability::Mut);
+
+    pub fn prefix_str(self) -> &'static str {
+        match self {
+            Self::NONE => "",
+            Self::REF => "ref ",
+            Self::MUT => "mut ",
+            Self::REF_MUT => "ref mut ",
+        }
+    }
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
@@ -715,7 +716,7 @@ pub enum PatKind {
     /// or a unit struct/variant pattern, or a const pattern (in the last two cases the third
     /// field must be `None`). Disambiguation cannot be done with parser alone, so it happens
     /// during name resolution.
-    Ident(BindingMode, Ident, Option<P<Pat>>),
+    Ident(BindingAnnotation, Ident, Option<P<Pat>>),
 
     /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
     /// The `bool` is `true` in the presence of a `..`.
@@ -936,8 +937,8 @@ impl Stmt {
     /// a trailing semicolon.
     ///
     /// This only modifies the parsed AST struct, not the attached
-    /// `LazyTokenStream`. The parser is responsible for calling
-    /// `CreateTokenStream::add_trailing_semi` when there is actually
+    /// `LazyAttrTokenStream`. The parser is responsible for calling
+    /// `ToAttrTokenStream::add_trailing_semi` when there is actually
     /// a semicolon in the tokenstream.
     pub fn add_trailing_semicolon(mut self) -> Self {
         self.kind = match self.kind {
@@ -983,7 +984,7 @@ pub struct MacCallStmt {
     pub mac: P<MacCall>,
     pub style: MacStmtStyle,
     pub attrs: AttrVec,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug)]
@@ -1008,7 +1009,7 @@ pub struct Local {
     pub kind: LocalKind,
     pub span: Span,
     pub attrs: AttrVec,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
@@ -1107,7 +1108,7 @@ pub struct Expr {
     pub kind: ExprKind,
     pub span: Span,
     pub attrs: AttrVec,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 impl Expr {
@@ -1966,7 +1967,7 @@ pub struct Ty {
     pub id: NodeId,
     pub kind: TyKind,
     pub span: Span,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 impl Clone for Ty {
@@ -2071,6 +2072,7 @@ impl TyKind {
 #[derive(Clone, Copy, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum TraitObjectSyntax {
     Dyn,
+    DynStar,
     None,
 }
 
@@ -2086,15 +2088,15 @@ pub enum InlineAsmRegOrRegClass {
 bitflags::bitflags! {
     #[derive(Encodable, Decodable, HashStable_Generic)]
     pub struct InlineAsmOptions: u16 {
-        const PURE = 1 << 0;
-        const NOMEM = 1 << 1;
-        const READONLY = 1 << 2;
+        const PURE            = 1 << 0;
+        const NOMEM           = 1 << 1;
+        const READONLY        = 1 << 2;
         const PRESERVES_FLAGS = 1 << 3;
-        const NORETURN = 1 << 4;
-        const NOSTACK = 1 << 5;
-        const ATT_SYNTAX = 1 << 6;
-        const RAW = 1 << 7;
-        const MAY_UNWIND = 1 << 8;
+        const NORETURN        = 1 << 4;
+        const NOSTACK         = 1 << 5;
+        const ATT_SYNTAX      = 1 << 6;
+        const RAW             = 1 << 7;
+        const MAY_UNWIND      = 1 << 8;
     }
 }
 
@@ -2230,7 +2232,7 @@ pub type ExplicitSelf = Spanned<SelfKind>;
 impl Param {
     /// Attempts to cast parameter to `ExplicitSelf`.
     pub fn to_self(&self) -> Option<ExplicitSelf> {
-        if let PatKind::Ident(BindingMode::ByValue(mutbl), ident, _) = self.pat.kind {
+        if let PatKind::Ident(BindingAnnotation(ByRef::No, mutbl), ident, _) = self.pat.kind {
             if ident.name == kw::SelfLower {
                 return match self.ty.kind {
                     TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
@@ -2260,23 +2262,10 @@ impl Param {
     pub fn from_self(attrs: AttrVec, eself: ExplicitSelf, eself_ident: Ident) -> Param {
         let span = eself.span.to(eself_ident.span);
         let infer_ty = P(Ty { id: DUMMY_NODE_ID, kind: TyKind::ImplicitSelf, span, tokens: None });
-        let param = |mutbl, ty| Param {
-            attrs,
-            pat: P(Pat {
-                id: DUMMY_NODE_ID,
-                kind: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
-                span,
-                tokens: None,
-            }),
-            span,
-            ty,
-            id: DUMMY_NODE_ID,
-            is_placeholder: false,
-        };
-        match eself.node {
-            SelfKind::Explicit(ty, mutbl) => param(mutbl, ty),
-            SelfKind::Value(mutbl) => param(mutbl, infer_ty),
-            SelfKind::Region(lt, mutbl) => param(
+        let (mutbl, ty) = match eself.node {
+            SelfKind::Explicit(ty, mutbl) => (mutbl, ty),
+            SelfKind::Value(mutbl) => (mutbl, infer_ty),
+            SelfKind::Region(lt, mutbl) => (
                 Mutability::Not,
                 P(Ty {
                     id: DUMMY_NODE_ID,
@@ -2285,6 +2274,19 @@ impl Param {
                     tokens: None,
                 }),
             ),
+        };
+        Param {
+            attrs,
+            pat: P(Pat {
+                id: DUMMY_NODE_ID,
+                kind: PatKind::Ident(BindingAnnotation(ByRef::No, mutbl), eself_ident, None),
+                span,
+                tokens: None,
+            }),
+            span,
+            ty,
+            id: DUMMY_NODE_ID,
+            is_placeholder: false,
         }
     }
 }
@@ -2336,9 +2338,9 @@ impl Async {
     }
 
     /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
-    pub fn opt_return_id(self) -> Option<NodeId> {
+    pub fn opt_return_id(self) -> Option<(NodeId, Span)> {
         match self {
-            Async::Yes { return_impl_trait_id, .. } => Some(return_impl_trait_id),
+            Async::Yes { return_impl_trait_id, span, .. } => Some((return_impl_trait_id, span)),
             Async::No => None,
         }
     }
@@ -2522,8 +2524,8 @@ impl<S: Encoder> Encodable<S> for AttrId {
 }
 
 impl<D: Decoder> Decodable<D> for AttrId {
-    fn decode(_: &mut D) -> AttrId {
-        crate::attr::mk_attr_id()
+    default fn decode(_: &mut D) -> AttrId {
+        panic!("cannot decode `AttrId` with `{}`", std::any::type_name::<D>());
     }
 }
 
@@ -2531,7 +2533,7 @@ impl<D: Decoder> Decodable<D> for AttrId {
 pub struct AttrItem {
     pub path: Path,
     pub args: MacArgs,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 /// A list of attributes.
@@ -2551,7 +2553,7 @@ pub struct Attribute {
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct NormalAttr {
     pub item: AttrItem,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
@@ -2602,7 +2604,7 @@ impl PolyTraitRef {
 pub struct Visibility {
     pub kind: VisibilityKind,
     pub span: Span,
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
@@ -2688,7 +2690,7 @@ pub struct Item<K = ItemKind> {
     ///
     /// Note that the tokens here do not include the outer attributes, but will
     /// include inner attributes.
-    pub tokens: Option<LazyTokenStream>,
+    pub tokens: Option<LazyAttrTokenStream>,
 }
 
 impl Item {
@@ -3044,9 +3046,10 @@ mod size_asserts {
     static_assert_size!(Block, 48);
     static_assert_size!(Expr, 104);
     static_assert_size!(ExprKind, 72);
-    static_assert_size!(Fn, 192);
+    static_assert_size!(Fn, 184);
     static_assert_size!(ForeignItem, 96);
     static_assert_size!(ForeignItemKind, 24);
+    static_assert_size!(GenericArg, 24);
     static_assert_size!(GenericBound, 88);
     static_assert_size!(Generics, 72);
     static_assert_size!(Impl, 200);
@@ -3054,6 +3057,8 @@ mod size_asserts {
     static_assert_size!(ItemKind, 112);
     static_assert_size!(Lit, 48);
     static_assert_size!(LitKind, 24);
+    static_assert_size!(Local, 72);
+    static_assert_size!(Param, 40);
     static_assert_size!(Pat, 120);
     static_assert_size!(PatKind, 96);
     static_assert_size!(Path, 40);
diff --git a/compiler/rustc_ast/src/ast_traits.rs b/compiler/rustc_ast/src/ast_traits.rs
index 0947a71b8243..1b31be07f7ad 100644
--- a/compiler/rustc_ast/src/ast_traits.rs
+++ b/compiler/rustc_ast/src/ast_traits.rs
@@ -4,7 +4,7 @@
 
 use crate::ptr::P;
 use crate::token::Nonterminal;
-use crate::tokenstream::LazyTokenStream;
+use crate::tokenstream::LazyAttrTokenStream;
 use crate::{Arm, Crate, ExprField, FieldDef, GenericParam, Param, PatField, Variant};
 use crate::{AssocItem, Expr, ForeignItem, Item, NodeId};
 use crate::{AttrItem, AttrKind, Block, Pat, Path, Ty, Visibility};
@@ -124,18 +124,18 @@ impl HasSpan for AttrItem {
 
 /// A trait for AST nodes having (or not having) collected tokens.
 pub trait HasTokens {
-    fn tokens(&self) -> Option<&LazyTokenStream>;
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>>;
+    fn tokens(&self) -> Option<&LazyAttrTokenStream>;
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>>;
 }
 
 macro_rules! impl_has_tokens {
     ($($T:ty),+ $(,)?) => {
         $(
             impl HasTokens for $T {
-                fn tokens(&self) -> Option<&LazyTokenStream> {
+                fn tokens(&self) -> Option<&LazyAttrTokenStream> {
                     self.tokens.as_ref()
                 }
-                fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+                fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
                     Some(&mut self.tokens)
                 }
             }
@@ -147,10 +147,10 @@ macro_rules! impl_has_tokens_none {
     ($($T:ty),+ $(,)?) => {
         $(
             impl HasTokens for $T {
-                fn tokens(&self) -> Option<&LazyTokenStream> {
+                fn tokens(&self) -> Option<&LazyAttrTokenStream> {
                     None
                 }
-                fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+                fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
                     None
                 }
             }
@@ -162,25 +162,25 @@ impl_has_tokens!(AssocItem, AttrItem, Block, Expr, ForeignItem, Item, Pat, Path,
 impl_has_tokens_none!(Arm, ExprField, FieldDef, GenericParam, Param, PatField, Variant);
 
 impl<T: AstDeref<Target: HasTokens>> HasTokens for T {
-    fn tokens(&self) -> Option<&LazyTokenStream> {
+    fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         self.ast_deref().tokens()
     }
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
         self.ast_deref_mut().tokens_mut()
     }
 }
 
 impl<T: HasTokens> HasTokens for Option<T> {
-    fn tokens(&self) -> Option<&LazyTokenStream> {
+    fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         self.as_ref().and_then(|inner| inner.tokens())
     }
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
         self.as_mut().and_then(|inner| inner.tokens_mut())
     }
 }
 
 impl HasTokens for StmtKind {
-    fn tokens(&self) -> Option<&LazyTokenStream> {
+    fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         match self {
             StmtKind::Local(local) => local.tokens.as_ref(),
             StmtKind::Item(item) => item.tokens(),
@@ -189,7 +189,7 @@ impl HasTokens for StmtKind {
             StmtKind::MacCall(mac) => mac.tokens.as_ref(),
         }
     }
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
         match self {
             StmtKind::Local(local) => Some(&mut local.tokens),
             StmtKind::Item(item) => item.tokens_mut(),
@@ -201,16 +201,16 @@ impl HasTokens for StmtKind {
 }
 
 impl HasTokens for Stmt {
-    fn tokens(&self) -> Option<&LazyTokenStream> {
+    fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         self.kind.tokens()
     }
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
         self.kind.tokens_mut()
     }
 }
 
 impl HasTokens for Attribute {
-    fn tokens(&self) -> Option<&LazyTokenStream> {
+    fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         match &self.kind {
             AttrKind::Normal(normal) => normal.tokens.as_ref(),
             kind @ AttrKind::DocComment(..) => {
@@ -218,7 +218,7 @@ impl HasTokens for Attribute {
             }
         }
     }
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
         Some(match &mut self.kind {
             AttrKind::Normal(normal) => &mut normal.tokens,
             kind @ AttrKind::DocComment(..) => {
@@ -229,7 +229,7 @@ impl HasTokens for Attribute {
 }
 
 impl HasTokens for Nonterminal {
-    fn tokens(&self) -> Option<&LazyTokenStream> {
+    fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         match self {
             Nonterminal::NtItem(item) => item.tokens(),
             Nonterminal::NtStmt(stmt) => stmt.tokens(),
@@ -243,7 +243,7 @@ impl HasTokens for Nonterminal {
             Nonterminal::NtIdent(..) | Nonterminal::NtLifetime(..) => None,
         }
     }
-    fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
+    fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>> {
         match self {
             Nonterminal::NtItem(item) => item.tokens_mut(),
             Nonterminal::NtStmt(stmt) => stmt.tokens_mut(),
@@ -279,6 +279,7 @@ macro_rules! impl_has_attrs {
             impl HasAttrs for $T {
                 const SUPPORTS_CUSTOM_INNER_ATTRS: bool = $inner;
 
+                #[inline]
                 fn attrs(&self) -> &[Attribute] {
                     &self.attrs
                 }
diff --git a/compiler/rustc_ast/src/attr/mod.rs b/compiler/rustc_ast/src/attr/mod.rs
index 5b72ec2b6015..990f4f8f1329 100644
--- a/compiler/rustc_ast/src/attr/mod.rs
+++ b/compiler/rustc_ast/src/attr/mod.rs
@@ -7,17 +7,22 @@ use crate::ast::{MacArgs, MacArgsEq, MacDelimiter, MetaItem, MetaItemKind, Neste
 use crate::ast::{Path, PathSegment};
 use crate::ptr::P;
 use crate::token::{self, CommentKind, Delimiter, Token};
-use crate::tokenstream::{AttrAnnotatedTokenStream, AttrAnnotatedTokenTree};
 use crate::tokenstream::{DelimSpan, Spacing, TokenTree};
-use crate::tokenstream::{LazyTokenStream, TokenStream};
+use crate::tokenstream::{LazyAttrTokenStream, TokenStream};
 use crate::util::comments;
 
+use rustc_data_structures::sync::WorkerLocal;
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_span::source_map::BytePos;
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::Span;
 
+use std::cell::Cell;
 use std::iter;
+#[cfg(debug_assertions)]
+use std::ops::BitXor;
+#[cfg(debug_assertions)]
+use std::sync::atomic::{AtomicU32, Ordering};
 
 pub struct MarkedAttrs(GrowableBitSet<AttrId>);
 
@@ -232,6 +237,9 @@ impl AttrItem {
 }
 
 impl Attribute {
+    /// Returns `true` if it is a sugared doc comment (`///` or `//!` for example).
+    /// So `#[doc = "doc"]` (which is a doc comment) and `#[doc(...)]` (which is not
+    /// a doc comment) will return `false`.
     pub fn is_doc_comment(&self) -> bool {
         match self.kind {
             AttrKind::Normal(..) => false,
@@ -239,6 +247,11 @@ impl Attribute {
         }
     }
 
+    /// Returns the documentation and its kind if this is a doc comment or a sugared doc comment.
+    /// * `///doc` returns `Some(("doc", CommentKind::Line))`.
+    /// * `/** doc */` returns `Some(("doc", CommentKind::Block))`.
+    /// * `#[doc = "doc"]` returns `Some(("doc", CommentKind::Line))`.
+    /// * `#[doc(...)]` returns `None`.
     pub fn doc_str_and_comment_kind(&self) -> Option<(Symbol, CommentKind)> {
         match self.kind {
             AttrKind::DocComment(kind, data) => Some((data, kind)),
@@ -251,6 +264,10 @@ impl Attribute {
         }
     }
 
+    /// Returns the documentation if this is a doc comment or a sugared doc comment.
+    /// * `///doc` returns `Some("doc")`.
+    /// * `#[doc = "doc"]` returns `Some("doc")`.
+    /// * `#[doc(...)]` returns `None`.
     pub fn doc_str(&self) -> Option<Symbol> {
         match self.kind {
             AttrKind::DocComment(.., data) => Some(data),
@@ -294,20 +311,18 @@ impl Attribute {
         }
     }
 
-    pub fn tokens(&self) -> AttrAnnotatedTokenStream {
+    pub fn tokens(&self) -> TokenStream {
         match self.kind {
             AttrKind::Normal(ref normal) => normal
                 .tokens
                 .as_ref()
                 .unwrap_or_else(|| panic!("attribute is missing tokens: {:?}", self))
-                .create_token_stream(),
-            AttrKind::DocComment(comment_kind, data) => AttrAnnotatedTokenStream::from((
-                AttrAnnotatedTokenTree::Token(Token::new(
-                    token::DocComment(comment_kind, self.style, data),
-                    self.span,
-                )),
+                .to_attr_token_stream()
+                .to_tokenstream(),
+            AttrKind::DocComment(comment_kind, data) => TokenStream::new(vec![TokenTree::Token(
+                Token::new(token::DocComment(comment_kind, self.style, data), self.span),
                 Spacing::Alone,
-            )),
+            )]),
         }
     }
 }
@@ -337,52 +352,86 @@ pub fn mk_nested_word_item(ident: Ident) -> NestedMetaItem {
     NestedMetaItem::MetaItem(mk_word_item(ident))
 }
 
-pub(crate) fn mk_attr_id() -> AttrId {
-    use std::sync::atomic::AtomicU32;
-    use std::sync::atomic::Ordering;
+pub struct AttrIdGenerator(WorkerLocal<Cell<u32>>);
 
-    static NEXT_ATTR_ID: AtomicU32 = AtomicU32::new(0);
+#[cfg(debug_assertions)]
+static MAX_ATTR_ID: AtomicU32 = AtomicU32::new(u32::MAX);
 
-    let id = NEXT_ATTR_ID.fetch_add(1, Ordering::SeqCst);
-    assert!(id != u32::MAX);
-    AttrId::from_u32(id)
+impl AttrIdGenerator {
+    pub fn new() -> Self {
+        // We use `(index as u32).reverse_bits()` to initialize the
+        // starting value of AttrId in each worker thread.
+        // The `index` is the index of the worker thread.
+        // This ensures that the AttrId generated in each thread is unique.
+        AttrIdGenerator(WorkerLocal::new(|index| {
+            let index: u32 = index.try_into().unwrap();
+
+            #[cfg(debug_assertions)]
+            {
+                let max_id = ((index + 1).next_power_of_two() - 1).bitxor(u32::MAX).reverse_bits();
+                MAX_ATTR_ID.fetch_min(max_id, Ordering::Release);
+            }
+
+            Cell::new(index.reverse_bits())
+        }))
+    }
+
+    pub fn mk_attr_id(&self) -> AttrId {
+        let id = self.0.get();
+
+        // Ensure the assigned attr_id does not overlap the bits
+        // representing the number of threads.
+        #[cfg(debug_assertions)]
+        assert!(id <= MAX_ATTR_ID.load(Ordering::Acquire));
+
+        self.0.set(id + 1);
+        AttrId::from_u32(id)
+    }
 }
 
-pub fn mk_attr(style: AttrStyle, path: Path, args: MacArgs, span: Span) -> Attribute {
-    mk_attr_from_item(AttrItem { path, args, tokens: None }, None, style, span)
+pub fn mk_attr(
+    g: &AttrIdGenerator,
+    style: AttrStyle,
+    path: Path,
+    args: MacArgs,
+    span: Span,
+) -> Attribute {
+    mk_attr_from_item(g, AttrItem { path, args, tokens: None }, None, style, span)
 }
 
 pub fn mk_attr_from_item(
+    g: &AttrIdGenerator,
     item: AttrItem,
-    tokens: Option<LazyTokenStream>,
+    tokens: Option<LazyAttrTokenStream>,
     style: AttrStyle,
     span: Span,
 ) -> Attribute {
     Attribute {
         kind: AttrKind::Normal(P(ast::NormalAttr { item, tokens })),
-        id: mk_attr_id(),
+        id: g.mk_attr_id(),
         style,
         span,
     }
 }
 
 /// Returns an inner attribute with the given value and span.
-pub fn mk_attr_inner(item: MetaItem) -> Attribute {
-    mk_attr(AttrStyle::Inner, item.path, item.kind.mac_args(item.span), item.span)
+pub fn mk_attr_inner(g: &AttrIdGenerator, item: MetaItem) -> Attribute {
+    mk_attr(g, AttrStyle::Inner, item.path, item.kind.mac_args(item.span), item.span)
 }
 
 /// Returns an outer attribute with the given value and span.
-pub fn mk_attr_outer(item: MetaItem) -> Attribute {
-    mk_attr(AttrStyle::Outer, item.path, item.kind.mac_args(item.span), item.span)
+pub fn mk_attr_outer(g: &AttrIdGenerator, item: MetaItem) -> Attribute {
+    mk_attr(g, AttrStyle::Outer, item.path, item.kind.mac_args(item.span), item.span)
 }
 
 pub fn mk_doc_comment(
+    g: &AttrIdGenerator,
     comment_kind: CommentKind,
     style: AttrStyle,
     data: Symbol,
     span: Span,
 ) -> Attribute {
-    Attribute { kind: AttrKind::DocComment(comment_kind, data), id: mk_attr_id(), style, span }
+    Attribute { kind: AttrKind::DocComment(comment_kind, data), id: g.mk_attr_id(), style, span }
 }
 
 pub fn list_contains_name(items: &[NestedMetaItem], name: Symbol) -> bool {
diff --git a/compiler/rustc_ast/src/lib.rs b/compiler/rustc_ast/src/lib.rs
index 27061f300a2b..eeb7e56e2b12 100644
--- a/compiler/rustc_ast/src/lib.rs
+++ b/compiler/rustc_ast/src/lib.rs
@@ -13,7 +13,6 @@
 #![feature(const_default_impls)]
 #![feature(const_trait_impl)]
 #![feature(if_let_guard)]
-#![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
 #![feature(min_specialization)]
 #![feature(negative_impls)]
@@ -26,6 +25,9 @@
 #[macro_use]
 extern crate rustc_macros;
 
+#[macro_use]
+extern crate tracing;
+
 pub mod util {
     pub mod classify;
     pub mod comments;
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index 458d1156ec25..ad68d6e755e0 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -642,17 +642,17 @@ pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> Smal
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T) {
+pub fn visit_attr_tt<T: MutVisitor>(tt: &mut AttrTokenTree, vis: &mut T) {
     match tt {
-        AttrAnnotatedTokenTree::Token(token) => {
+        AttrTokenTree::Token(token, _) => {
             visit_token(token, vis);
         }
-        AttrAnnotatedTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
+        AttrTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
             vis.visit_span(open);
             vis.visit_span(close);
-            visit_attr_annotated_tts(tts, vis);
+            visit_attr_tts(tts, vis);
         }
-        AttrAnnotatedTokenTree::Attributes(data) => {
+        AttrTokenTree::Attributes(data) => {
             for attr in &mut *data.attrs {
                 match &mut attr.kind {
                     AttrKind::Normal(normal) => {
@@ -690,27 +690,27 @@ pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T)
     }
 }
 
-pub fn visit_attr_annotated_tts<T: MutVisitor>(
-    AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream,
-    vis: &mut T,
-) {
+pub fn visit_attr_tts<T: MutVisitor>(AttrTokenStream(tts): &mut AttrTokenStream, vis: &mut T) {
     if T::VISIT_TOKENS && !tts.is_empty() {
         let tts = Lrc::make_mut(tts);
-        visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis));
+        visit_vec(tts, |tree| visit_attr_tt(tree, vis));
     }
 }
 
-pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) {
+pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(
+    lazy_tts: Option<&mut LazyAttrTokenStream>,
+    vis: &mut T,
+) {
     if T::VISIT_TOKENS {
         if let Some(lazy_tts) = lazy_tts {
-            let mut tts = lazy_tts.create_token_stream();
-            visit_attr_annotated_tts(&mut tts, vis);
-            *lazy_tts = LazyTokenStream::new(tts);
+            let mut tts = lazy_tts.to_attr_token_stream();
+            visit_attr_tts(&mut tts, vis);
+            *lazy_tts = LazyAttrTokenStream::new(tts);
         }
     }
 }
 
-pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
+pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyAttrTokenStream>, vis: &mut T) {
     visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
 }
 
diff --git a/compiler/rustc_ast/src/node_id.rs b/compiler/rustc_ast/src/node_id.rs
index 7f928cb57618..7b5acc3f4859 100644
--- a/compiler/rustc_ast/src/node_id.rs
+++ b/compiler/rustc_ast/src/node_id.rs
@@ -13,7 +13,7 @@ rustc_index::newtype_index! {
     }
 }
 
-rustc_data_structures::define_id_collections!(NodeMap, NodeSet, NodeId);
+rustc_data_structures::define_id_collections!(NodeMap, NodeSet, NodeMapEntry, NodeId);
 
 /// The [`NodeId`] used to represent the root of the crate.
 pub const CRATE_NODE_ID: NodeId = NodeId::from_u32(0);
diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs
index dd98946b4cc5..97dfb7837674 100644
--- a/compiler/rustc_ast/src/token.rs
+++ b/compiler/rustc_ast/src/token.rs
@@ -398,6 +398,30 @@ impl Token {
         }
     }
 
+    /// Returns `true` if the token can appear at the start of an pattern.
+    ///
+    /// Shamelessly borrowed from `can_begin_expr`, only used for diagnostics right now.
+    pub fn can_begin_pattern(&self) -> bool {
+        match self.uninterpolate().kind {
+            Ident(name, is_raw)              =>
+                ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
+            | OpenDelim(Delimiter::Bracket | Delimiter::Parenthesis)  // tuple or array
+            | Literal(..)                        // literal
+            | BinOp(Minus)                       // unary minus
+            | BinOp(And)                         // reference
+            | AndAnd                             // double reference
+            // DotDotDot is no longer supported
+            | DotDot | DotDotDot | DotDotEq      // ranges
+            | Lt | BinOp(Shl)                    // associated path
+            | ModSep                    => true, // global path
+            Interpolated(ref nt) => matches!(**nt, NtLiteral(..) |
+                NtPat(..)     |
+                NtBlock(..)   |
+                NtPath(..)),
+            _ => false,
+        }
+    }
+
     /// Returns `true` if the token can appear at the start of a type.
     pub fn can_begin_type(&self) -> bool {
         match self.uninterpolate().kind {
@@ -449,6 +473,7 @@ impl Token {
                 kw::Extern,
                 kw::Impl,
                 kw::Unsafe,
+                kw::Const,
                 kw::Static,
                 kw::Union,
                 kw::Macro,
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 9e4a22e1fa3c..875cd620dfc6 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -121,12 +121,12 @@ where
     }
 }
 
-pub trait CreateTokenStream: sync::Send + sync::Sync {
-    fn create_token_stream(&self) -> AttrAnnotatedTokenStream;
+pub trait ToAttrTokenStream: sync::Send + sync::Sync {
+    fn to_attr_token_stream(&self) -> AttrTokenStream;
 }
 
-impl CreateTokenStream for AttrAnnotatedTokenStream {
-    fn create_token_stream(&self) -> AttrAnnotatedTokenStream {
+impl ToAttrTokenStream for AttrTokenStream {
+    fn to_attr_token_stream(&self) -> AttrTokenStream {
         self.clone()
     }
 }
@@ -135,68 +135,68 @@ impl CreateTokenStream for AttrAnnotatedTokenStream {
 /// of an actual `TokenStream` until it is needed.
 /// `Box` is here only to reduce the structure size.
 #[derive(Clone)]
-pub struct LazyTokenStream(Lrc<Box<dyn CreateTokenStream>>);
+pub struct LazyAttrTokenStream(Lrc<Box<dyn ToAttrTokenStream>>);
 
-impl LazyTokenStream {
-    pub fn new(inner: impl CreateTokenStream + 'static) -> LazyTokenStream {
-        LazyTokenStream(Lrc::new(Box::new(inner)))
+impl LazyAttrTokenStream {
+    pub fn new(inner: impl ToAttrTokenStream + 'static) -> LazyAttrTokenStream {
+        LazyAttrTokenStream(Lrc::new(Box::new(inner)))
     }
 
-    pub fn create_token_stream(&self) -> AttrAnnotatedTokenStream {
-        self.0.create_token_stream()
+    pub fn to_attr_token_stream(&self) -> AttrTokenStream {
+        self.0.to_attr_token_stream()
     }
 }
 
-impl fmt::Debug for LazyTokenStream {
+impl fmt::Debug for LazyAttrTokenStream {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "LazyTokenStream({:?})", self.create_token_stream())
+        write!(f, "LazyAttrTokenStream({:?})", self.to_attr_token_stream())
     }
 }
 
-impl<S: Encoder> Encodable<S> for LazyTokenStream {
+impl<S: Encoder> Encodable<S> for LazyAttrTokenStream {
     fn encode(&self, s: &mut S) {
         // Used by AST json printing.
-        Encodable::encode(&self.create_token_stream(), s);
+        Encodable::encode(&self.to_attr_token_stream(), s);
     }
 }
 
-impl<D: Decoder> Decodable<D> for LazyTokenStream {
+impl<D: Decoder> Decodable<D> for LazyAttrTokenStream {
     fn decode(_d: &mut D) -> Self {
-        panic!("Attempted to decode LazyTokenStream");
+        panic!("Attempted to decode LazyAttrTokenStream");
     }
 }
 
-impl<CTX> HashStable<CTX> for LazyTokenStream {
+impl<CTX> HashStable<CTX> for LazyAttrTokenStream {
     fn hash_stable(&self, _hcx: &mut CTX, _hasher: &mut StableHasher) {
-        panic!("Attempted to compute stable hash for LazyTokenStream");
+        panic!("Attempted to compute stable hash for LazyAttrTokenStream");
     }
 }
 
-/// A `AttrAnnotatedTokenStream` is similar to a `TokenStream`, but with extra
+/// An `AttrTokenStream` is similar to a `TokenStream`, but with extra
 /// information about the tokens for attribute targets. This is used
 /// during expansion to perform early cfg-expansion, and to process attributes
 /// during proc-macro invocations.
 #[derive(Clone, Debug, Default, Encodable, Decodable)]
-pub struct AttrAnnotatedTokenStream(pub Lrc<Vec<(AttrAnnotatedTokenTree, Spacing)>>);
+pub struct AttrTokenStream(pub Lrc<Vec<AttrTokenTree>>);
 
-/// Like `TokenTree`, but for `AttrAnnotatedTokenStream`
+/// Like `TokenTree`, but for `AttrTokenStream`.
 #[derive(Clone, Debug, Encodable, Decodable)]
-pub enum AttrAnnotatedTokenTree {
-    Token(Token),
-    Delimited(DelimSpan, Delimiter, AttrAnnotatedTokenStream),
+pub enum AttrTokenTree {
+    Token(Token, Spacing),
+    Delimited(DelimSpan, Delimiter, AttrTokenStream),
     /// Stores the attributes for an attribute target,
     /// along with the tokens for that attribute target.
     /// See `AttributesData` for more information
     Attributes(AttributesData),
 }
 
-impl AttrAnnotatedTokenStream {
-    pub fn new(tokens: Vec<(AttrAnnotatedTokenTree, Spacing)>) -> AttrAnnotatedTokenStream {
-        AttrAnnotatedTokenStream(Lrc::new(tokens))
+impl AttrTokenStream {
+    pub fn new(tokens: Vec<AttrTokenTree>) -> AttrTokenStream {
+        AttrTokenStream(Lrc::new(tokens))
     }
 
-    /// Converts this `AttrAnnotatedTokenStream` to a plain `TokenStream
-    /// During conversion, `AttrAnnotatedTokenTree::Attributes` get 'flattened'
+    /// Converts this `AttrTokenStream` to a plain `TokenStream`.
+    /// During conversion, `AttrTokenTree::Attributes` get 'flattened'
     /// back to a `TokenStream` of the form `outer_attr attr_target`.
     /// If there are inner attributes, they are inserted into the proper
     /// place in the attribute target tokens.
@@ -204,31 +204,27 @@ impl AttrAnnotatedTokenStream {
         let trees: Vec<_> = self
             .0
             .iter()
-            .flat_map(|tree| match &tree.0 {
-                AttrAnnotatedTokenTree::Token(inner) => {
-                    smallvec![TokenTree::Token(inner.clone(), tree.1)].into_iter()
+            .flat_map(|tree| match &tree {
+                AttrTokenTree::Token(inner, spacing) => {
+                    smallvec![TokenTree::Token(inner.clone(), *spacing)].into_iter()
                 }
-                AttrAnnotatedTokenTree::Delimited(span, delim, stream) => {
+                AttrTokenTree::Delimited(span, delim, stream) => {
                     smallvec![TokenTree::Delimited(*span, *delim, stream.to_tokenstream()),]
                         .into_iter()
                 }
-                AttrAnnotatedTokenTree::Attributes(data) => {
+                AttrTokenTree::Attributes(data) => {
                     let mut outer_attrs = Vec::new();
                     let mut inner_attrs = Vec::new();
                     for attr in &data.attrs {
                         match attr.style {
-                            crate::AttrStyle::Outer => {
-                                outer_attrs.push(attr);
-                            }
-                            crate::AttrStyle::Inner => {
-                                inner_attrs.push(attr);
-                            }
+                            crate::AttrStyle::Outer => outer_attrs.push(attr),
+                            crate::AttrStyle::Inner => inner_attrs.push(attr),
                         }
                     }
 
                     let mut target_tokens: Vec<_> = data
                         .tokens
-                        .create_token_stream()
+                        .to_attr_token_stream()
                         .to_tokenstream()
                         .0
                         .iter()
@@ -239,9 +235,9 @@ impl AttrAnnotatedTokenStream {
                         // Check the last two trees (to account for a trailing semi)
                         for tree in target_tokens.iter_mut().rev().take(2) {
                             if let TokenTree::Delimited(span, delim, delim_tokens) = tree {
-                                // Inner attributes are only supported on extern blocks, functions, impls,
-                                // and modules. All of these have their inner attributes placed at
-                                // the beginning of the rightmost outermost braced group:
+                                // Inner attributes are only supported on extern blocks, functions,
+                                // impls, and modules. All of these have their inner attributes
+                                // placed at the beginning of the rightmost outermost braced group:
                                 // e.g. fn foo() { #![my_attr} }
                                 //
                                 // Therefore, we can insert them back into the right location
@@ -255,7 +251,7 @@ impl AttrAnnotatedTokenStream {
 
                                 let mut builder = TokenStreamBuilder::new();
                                 for inner_attr in inner_attrs {
-                                    builder.push(inner_attr.tokens().to_tokenstream());
+                                    builder.push(inner_attr.tokens());
                                 }
                                 builder.push(delim_tokens.clone());
                                 *tree = TokenTree::Delimited(*span, *delim, builder.build());
@@ -273,7 +269,7 @@ impl AttrAnnotatedTokenStream {
                     let mut flat: SmallVec<[_; 1]> = SmallVec::new();
                     for attr in outer_attrs {
                         // FIXME: Make this more efficient
-                        flat.extend(attr.tokens().to_tokenstream().0.clone().iter().cloned());
+                        flat.extend(attr.tokens().0.clone().iter().cloned());
                     }
                     flat.extend(target_tokens);
                     flat.into_iter()
@@ -300,7 +296,7 @@ pub struct AttributesData {
     pub attrs: AttrVec,
     /// The underlying tokens for the attribute target that `attrs`
     /// are applied to
-    pub tokens: LazyTokenStream,
+    pub tokens: LazyAttrTokenStream,
 }
 
 /// A `TokenStream` is an abstract sequence of tokens, organized into [`TokenTree`]s.
@@ -363,12 +359,6 @@ impl TokenStream {
     }
 }
 
-impl From<(AttrAnnotatedTokenTree, Spacing)> for AttrAnnotatedTokenStream {
-    fn from((tree, spacing): (AttrAnnotatedTokenTree, Spacing)) -> AttrAnnotatedTokenStream {
-        AttrAnnotatedTokenStream::new(vec![(tree, spacing)])
-    }
-}
-
 impl iter::FromIterator<TokenTree> for TokenStream {
     fn from_iter<I: IntoIterator<Item = TokenTree>>(iter: I) -> Self {
         TokenStream::new(iter.into_iter().collect::<Vec<TokenTree>>())
@@ -420,21 +410,6 @@ impl TokenStream {
         TokenStream(Lrc::new(self.0.iter().enumerate().map(|(i, tree)| f(i, tree)).collect()))
     }
 
-    fn opt_from_ast(node: &(impl HasAttrs + HasTokens)) -> Option<TokenStream> {
-        let tokens = node.tokens()?;
-        let attrs = node.attrs();
-        let attr_annotated = if attrs.is_empty() {
-            tokens.create_token_stream()
-        } else {
-            let attr_data = AttributesData { attrs: attrs.to_vec().into(), tokens: tokens.clone() };
-            AttrAnnotatedTokenStream::new(vec![(
-                AttrAnnotatedTokenTree::Attributes(attr_data),
-                Spacing::Alone,
-            )])
-        };
-        Some(attr_annotated.to_tokenstream())
-    }
-
     // Create a token stream containing a single token with alone spacing.
     pub fn token_alone(kind: TokenKind, span: Span) -> TokenStream {
         TokenStream::new(vec![TokenTree::token_alone(kind, span)])
@@ -451,8 +426,18 @@ impl TokenStream {
     }
 
     pub fn from_ast(node: &(impl HasAttrs + HasSpan + HasTokens + fmt::Debug)) -> TokenStream {
-        TokenStream::opt_from_ast(node)
-            .unwrap_or_else(|| panic!("missing tokens for node at {:?}: {:?}", node.span(), node))
+        let Some(tokens) = node.tokens() else {
+            panic!("missing tokens for node at {:?}: {:?}", node.span(), node);
+        };
+        let attrs = node.attrs();
+        let attr_stream = if attrs.is_empty() {
+            tokens.to_attr_token_stream()
+        } else {
+            let attr_data =
+                AttributesData { attrs: attrs.iter().cloned().collect(), tokens: tokens.clone() };
+            AttrTokenStream::new(vec![AttrTokenTree::Attributes(attr_data)])
+        };
+        attr_stream.to_tokenstream()
     }
 
     pub fn from_nonterminal_ast(nt: &Nonterminal) -> TokenStream {
@@ -555,7 +540,7 @@ impl TokenStreamBuilder {
 
                 // Get the first stream, which will become the result stream.
                 // If it's `None`, create an empty stream.
-                let mut iter = streams.drain(..);
+                let mut iter = streams.into_iter();
                 let mut res_stream_lrc = iter.next().unwrap().0;
 
                 // Append the subsequent elements to the result stream, after
diff --git a/compiler/rustc_ast/src/util/literal.rs b/compiler/rustc_ast/src/util/literal.rs
index 69a78d165ef5..536b385606c6 100644
--- a/compiler/rustc_ast/src/util/literal.rs
+++ b/compiler/rustc_ast/src/util/literal.rs
@@ -9,7 +9,6 @@ use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
 
 use std::ascii;
-use tracing::debug;
 
 pub enum LitError {
     NotLiteral,
@@ -164,12 +163,7 @@ impl LitKind {
             }
             LitKind::Str(symbol, ast::StrStyle::Raw(n)) => (token::StrRaw(n), symbol, None),
             LitKind::ByteStr(ref bytes) => {
-                let string = bytes
-                    .iter()
-                    .cloned()
-                    .flat_map(ascii::escape_default)
-                    .map(Into::<char>::into)
-                    .collect::<String>();
+                let string = bytes.escape_ascii().to_string();
                 (token::ByteStr, Symbol::intern(&string), None)
             }
             LitKind::Byte(byte) => {
diff --git a/compiler/rustc_ast/src/util/parser.rs b/compiler/rustc_ast/src/util/parser.rs
index 5edeb54be5f0..b40ad6f700e8 100644
--- a/compiler/rustc_ast/src/util/parser.rs
+++ b/compiler/rustc_ast/src/util/parser.rs
@@ -297,11 +297,11 @@ impl ExprPrecedence {
         match self {
             ExprPrecedence::Closure => PREC_CLOSURE,
 
-            ExprPrecedence::Break |
-            ExprPrecedence::Continue |
-            ExprPrecedence::Ret |
-            ExprPrecedence::Yield |
-            ExprPrecedence::Yeet => PREC_JUMP,
+            ExprPrecedence::Break
+            | ExprPrecedence::Continue
+            | ExprPrecedence::Ret
+            | ExprPrecedence::Yield
+            | ExprPrecedence::Yeet => PREC_JUMP,
 
             // `Range` claims to have higher precedence than `Assign`, but `x .. x = x` fails to
             // parse, instead of parsing as `(x .. x) = x`.  Giving `Range` a lower precedence
@@ -318,43 +318,43 @@ impl ExprPrecedence {
             ExprPrecedence::AssignOp => AssocOp::Assign.precedence() as i8,
 
             // Unary, prefix
-            ExprPrecedence::Box |
-            ExprPrecedence::AddrOf |
+            ExprPrecedence::Box
+            | ExprPrecedence::AddrOf
             // Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
             // However, this is not exactly right. When `let _ = a` is the LHS of a binop we
             // need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
             // but we need to print `(let _ = a) < b` as-is with parens.
-            ExprPrecedence::Let |
-            ExprPrecedence::Unary => PREC_PREFIX,
+            | ExprPrecedence::Let
+            | ExprPrecedence::Unary => PREC_PREFIX,
 
             // Unary, postfix
-            ExprPrecedence::Await |
-            ExprPrecedence::Call |
-            ExprPrecedence::MethodCall |
-            ExprPrecedence::Field |
-            ExprPrecedence::Index |
-            ExprPrecedence::Try |
-            ExprPrecedence::InlineAsm |
-            ExprPrecedence::Mac => PREC_POSTFIX,
+            ExprPrecedence::Await
+            | ExprPrecedence::Call
+            | ExprPrecedence::MethodCall
+            | ExprPrecedence::Field
+            | ExprPrecedence::Index
+            | ExprPrecedence::Try
+            | ExprPrecedence::InlineAsm
+            | ExprPrecedence::Mac => PREC_POSTFIX,
 
             // Never need parens
-            ExprPrecedence::Array |
-            ExprPrecedence::Repeat |
-            ExprPrecedence::Tup |
-            ExprPrecedence::Lit |
-            ExprPrecedence::Path |
-            ExprPrecedence::Paren |
-            ExprPrecedence::If |
-            ExprPrecedence::While |
-            ExprPrecedence::ForLoop |
-            ExprPrecedence::Loop |
-            ExprPrecedence::Match |
-            ExprPrecedence::ConstBlock |
-            ExprPrecedence::Block |
-            ExprPrecedence::TryBlock |
-            ExprPrecedence::Async |
-            ExprPrecedence::Struct |
-            ExprPrecedence::Err => PREC_PAREN,
+            ExprPrecedence::Array
+            | ExprPrecedence::Repeat
+            | ExprPrecedence::Tup
+            | ExprPrecedence::Lit
+            | ExprPrecedence::Path
+            | ExprPrecedence::Paren
+            | ExprPrecedence::If
+            | ExprPrecedence::While
+            | ExprPrecedence::ForLoop
+            | ExprPrecedence::Loop
+            | ExprPrecedence::Match
+            | ExprPrecedence::ConstBlock
+            | ExprPrecedence::Block
+            | ExprPrecedence::TryBlock
+            | ExprPrecedence::Async
+            | ExprPrecedence::Struct
+            | ExprPrecedence::Err => PREC_PAREN,
         }
     }
 }
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index f687bfeced84..a71e055a4b3e 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -156,8 +156,8 @@ pub trait Visitor<'ast>: Sized {
     fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
         walk_where_predicate(self, p)
     }
-    fn visit_fn(&mut self, fk: FnKind<'ast>, s: Span, _: NodeId) {
-        walk_fn(self, fk, s)
+    fn visit_fn(&mut self, fk: FnKind<'ast>, _: Span, _: NodeId) {
+        walk_fn(self, fk)
     }
     fn visit_assoc_item(&mut self, i: &'ast AssocItem, ctxt: AssocCtxt) {
         walk_assoc_item(self, i, ctxt)
@@ -201,11 +201,11 @@ pub trait Visitor<'ast>: Sized {
     fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
         walk_use_tree(self, use_tree, id)
     }
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
-        walk_path_segment(self, path_span, path_segment)
+    fn visit_path_segment(&mut self, path_segment: &'ast PathSegment) {
+        walk_path_segment(self, path_segment)
     }
-    fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
-        walk_generic_args(self, path_span, generic_args)
+    fn visit_generic_args(&mut self, generic_args: &'ast GenericArgs) {
+        walk_generic_args(self, generic_args)
     }
     fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
         walk_generic_arg(self, generic_arg)
@@ -435,7 +435,7 @@ pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
 
 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
     for segment in &path.segments {
-        visitor.visit_path_segment(path.span, segment);
+        visitor.visit_path_segment(segment);
     }
 }
 
@@ -457,18 +457,14 @@ pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree,
     }
 }
 
-pub fn walk_path_segment<'a, V: Visitor<'a>>(
-    visitor: &mut V,
-    path_span: Span,
-    segment: &'a PathSegment,
-) {
+pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V, segment: &'a PathSegment) {
     visitor.visit_ident(segment.ident);
     if let Some(ref args) = segment.args {
-        visitor.visit_generic_args(path_span, args);
+        visitor.visit_generic_args(args);
     }
 }
 
-pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
+pub fn walk_generic_args<'a, V>(visitor: &mut V, generic_args: &'a GenericArgs)
 where
     V: Visitor<'a>,
 {
@@ -502,7 +498,7 @@ where
 pub fn walk_assoc_constraint<'a, V: Visitor<'a>>(visitor: &mut V, constraint: &'a AssocConstraint) {
     visitor.visit_ident(constraint.ident);
     if let Some(ref gen_args) = constraint.gen_args {
-        visitor.visit_generic_args(gen_args.span(), gen_args);
+        visitor.visit_generic_args(gen_args);
     }
     match constraint.kind {
         AssocConstraintKind::Equality { ref term } => match term {
@@ -659,7 +655,7 @@ pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &
     visitor.visit_fn_ret_ty(&function_declaration.output);
 }
 
-pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>, _span: Span) {
+pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>) {
     match kind {
         FnKind::Fn(_, _, sig, _, generics, body) => {
             visitor.visit_generics(generics);
@@ -800,7 +796,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
             walk_list!(visitor, visit_expr, arguments);
         }
         ExprKind::MethodCall(ref segment, ref receiver, ref arguments, _span) => {
-            visitor.visit_path_segment(expression.span, segment);
+            visitor.visit_path_segment(segment);
             visitor.visit_expr(receiver);
             walk_list!(visitor, visit_expr, arguments);
         }
diff --git a/compiler/rustc_ast_lowering/Cargo.toml b/compiler/rustc_ast_lowering/Cargo.toml
index 474aff2e2aac..ce1c8d4997d7 100644
--- a/compiler/rustc_ast_lowering/Cargo.toml
+++ b/compiler/rustc_ast_lowering/Cargo.toml
@@ -8,17 +8,18 @@ doctest = false
 
 [dependencies]
 rustc_arena = { path = "../rustc_arena" }
-tracing = "0.1"
+rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
-rustc_hir = { path = "../rustc_hir" }
-rustc_target = { path = "../rustc_target" }
 rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_errors = { path = "../rustc_errors" }
+rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_query_system = { path = "../rustc_query_system" }
-rustc_span = { path = "../rustc_span" }
-rustc_errors = { path = "../rustc_errors" }
 rustc_session = { path = "../rustc_session" }
-rustc_ast = { path = "../rustc_ast" }
+rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+thin-vec = "0.2.8"
+tracing = "0.1"
diff --git a/compiler/rustc_ast_lowering/src/asm.rs b/compiler/rustc_ast_lowering/src/asm.rs
index 0dba9da63da2..85306d7184d8 100644
--- a/compiler/rustc_ast_lowering/src/asm.rs
+++ b/compiler/rustc_ast_lowering/src/asm.rs
@@ -155,26 +155,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 let op = match *op {
                     InlineAsmOperand::In { reg, ref expr } => hir::InlineAsmOperand::In {
                         reg: lower_reg(reg),
-                        expr: self.lower_expr_mut(expr),
+                        expr: self.lower_expr(expr),
                     },
                     InlineAsmOperand::Out { reg, late, ref expr } => hir::InlineAsmOperand::Out {
                         reg: lower_reg(reg),
                         late,
-                        expr: expr.as_ref().map(|expr| self.lower_expr_mut(expr)),
+                        expr: expr.as_ref().map(|expr| self.lower_expr(expr)),
                     },
                     InlineAsmOperand::InOut { reg, late, ref expr } => {
                         hir::InlineAsmOperand::InOut {
                             reg: lower_reg(reg),
                             late,
-                            expr: self.lower_expr_mut(expr),
+                            expr: self.lower_expr(expr),
                         }
                     }
                     InlineAsmOperand::SplitInOut { reg, late, ref in_expr, ref out_expr } => {
                         hir::InlineAsmOperand::SplitInOut {
                             reg: lower_reg(reg),
                             late,
-                            in_expr: self.lower_expr_mut(in_expr),
-                            out_expr: out_expr.as_ref().map(|expr| self.lower_expr_mut(expr)),
+                            in_expr: self.lower_expr(in_expr),
+                            out_expr: out_expr.as_ref().map(|expr| self.lower_expr(expr)),
                         }
                     }
                     InlineAsmOperand::Const { ref anon_const } => {
@@ -220,7 +220,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 &sym.qself,
                                 &sym.path,
                                 ParamMode::Optional,
-                                ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                                &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                             );
                             hir::InlineAsmOperand::SymStatic { path, def_id }
                         } else {
@@ -237,7 +237,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             // Wrap the expression in an AnonConst.
                             let parent_def_id = self.current_hir_id_owner;
                             let node_id = self.next_node_id();
-                            self.create_def(parent_def_id, node_id, DefPathData::AnonConst);
+                            self.create_def(parent_def_id.def_id, node_id, DefPathData::AnonConst);
                             let anon_const = AnonConst { id: node_id, value: P(expr) };
                             hir::InlineAsmOperand::SymFn {
                                 anon_const: self.lower_anon_const(&anon_const),
diff --git a/compiler/rustc_ast_lowering/src/block.rs b/compiler/rustc_ast_lowering/src/block.rs
index 7cbfe143b4d8..12a0cc0d2550 100644
--- a/compiler/rustc_ast_lowering/src/block.rs
+++ b/compiler/rustc_ast_lowering/src/block.rs
@@ -1,8 +1,6 @@
 use crate::{ImplTraitContext, ImplTraitPosition, LoweringContext};
 use rustc_ast::{Block, BlockCheckMode, Local, LocalKind, Stmt, StmtKind};
 use rustc_hir as hir;
-use rustc_session::parse::feature_err;
-use rustc_span::sym;
 
 use smallvec::SmallVec;
 
@@ -87,20 +85,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let ty = l
             .ty
             .as_ref()
-            .map(|t| self.lower_ty(t, ImplTraitContext::Disallowed(ImplTraitPosition::Variable)));
+            .map(|t| self.lower_ty(t, &ImplTraitContext::Disallowed(ImplTraitPosition::Variable)));
         let init = l.kind.init().map(|init| self.lower_expr(init));
         let hir_id = self.lower_node_id(l.id);
         let pat = self.lower_pat(&l.pat);
         let els = if let LocalKind::InitElse(_, els) = &l.kind {
-            if !self.tcx.features().let_else {
-                feature_err(
-                    &self.tcx.sess.parse_sess,
-                    sym::let_else,
-                    l.span,
-                    "`let...else` statements are unstable",
-                )
-                .emit();
-            }
             Some(self.lower_block(els, false))
         } else {
             None
diff --git a/compiler/rustc_ast_lowering/src/errors.rs b/compiler/rustc_ast_lowering/src/errors.rs
index 4adeaef9bbfa..63ff64b00bed 100644
--- a/compiler/rustc_ast_lowering/src/errors.rs
+++ b/compiler/rustc_ast_lowering/src/errors.rs
@@ -1,8 +1,8 @@
-use rustc_errors::{fluent, AddSubdiagnostic, Applicability, Diagnostic, DiagnosticArgFromDisplay};
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
+use rustc_errors::{fluent, AddToDiagnostic, Applicability, Diagnostic, DiagnosticArgFromDisplay};
+use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{symbol::Ident, Span, Symbol};
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::generic_type_with_parentheses, code = "E0214")]
 pub struct GenericTypeWithParentheses {
     #[primary_span]
@@ -18,7 +18,7 @@ pub struct UseAngleBrackets {
     pub close_param: Span,
 }
 
-impl AddSubdiagnostic for UseAngleBrackets {
+impl AddToDiagnostic for UseAngleBrackets {
     fn add_to_diagnostic(self, diag: &mut Diagnostic) {
         diag.multipart_suggestion(
             fluent::ast_lowering::use_angle_brackets,
@@ -28,18 +28,32 @@ impl AddSubdiagnostic for UseAngleBrackets {
     }
 }
 
-#[derive(SessionDiagnostic)]
-#[help]
+#[derive(Diagnostic)]
 #[diag(ast_lowering::invalid_abi, code = "E0703")]
+#[note]
 pub struct InvalidAbi {
     #[primary_span]
     #[label]
     pub span: Span,
     pub abi: Symbol,
-    pub valid_abis: String,
+    pub command: String,
+    #[subdiagnostic]
+    pub suggestion: Option<InvalidAbiSuggestion>,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Subdiagnostic)]
+#[suggestion(
+    ast_lowering::invalid_abi_suggestion,
+    code = "{suggestion}",
+    applicability = "maybe-incorrect"
+)]
+pub struct InvalidAbiSuggestion {
+    #[primary_span]
+    pub span: Span,
+    pub suggestion: String,
+}
+
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::assoc_ty_parentheses)]
 pub struct AssocTyParentheses {
     #[primary_span]
@@ -54,7 +68,7 @@ pub enum AssocTyParenthesesSub {
     NotEmpty { open_param: Span, close_param: Span },
 }
 
-impl AddSubdiagnostic for AssocTyParenthesesSub {
+impl AddToDiagnostic for AssocTyParenthesesSub {
     fn add_to_diagnostic(self, diag: &mut Diagnostic) {
         match self {
             Self::Empty { parentheses_span } => diag.multipart_suggestion(
@@ -71,7 +85,7 @@ impl AddSubdiagnostic for AssocTyParenthesesSub {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_lowering::misplaced_impl_trait, code = "E0562")]
 pub struct MisplacedImplTrait<'a> {
     #[primary_span]
@@ -79,14 +93,14 @@ pub struct MisplacedImplTrait<'a> {
     pub position: DiagnosticArgFromDisplay<'a>,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::rustc_box_attribute_error)]
 pub struct RustcBoxAttributeError {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::underscore_expr_lhs_assign)]
 pub struct UnderscoreExprLhsAssign {
     #[primary_span]
@@ -94,7 +108,7 @@ pub struct UnderscoreExprLhsAssign {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::base_expression_double_dot)]
 pub struct BaseExpressionDoubleDot {
     #[primary_span]
@@ -102,7 +116,7 @@ pub struct BaseExpressionDoubleDot {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::await_only_in_async_fn_and_blocks, code = "E0728")]
 pub struct AwaitOnlyInAsyncFnAndBlocks {
     #[primary_span]
@@ -112,21 +126,21 @@ pub struct AwaitOnlyInAsyncFnAndBlocks {
     pub item_span: Option<Span>,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::generator_too_many_parameters, code = "E0628")]
 pub struct GeneratorTooManyParameters {
     #[primary_span]
     pub fn_decl_span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::closure_cannot_be_static, code = "E0697")]
 pub struct ClosureCannotBeStatic {
     #[primary_span]
     pub fn_decl_span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[help]
 #[diag(ast_lowering::async_non_move_closure_not_supported, code = "E0708")]
 pub struct AsyncNonMoveClosureNotSupported {
@@ -134,7 +148,7 @@ pub struct AsyncNonMoveClosureNotSupported {
     pub fn_decl_span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::functional_record_update_destructuring_assignment)]
 pub struct FunctionalRecordUpdateDestructuringAssignemnt {
     #[primary_span]
@@ -142,28 +156,28 @@ pub struct FunctionalRecordUpdateDestructuringAssignemnt {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::async_generators_not_supported, code = "E0727")]
 pub struct AsyncGeneratorsNotSupported {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::inline_asm_unsupported_target, code = "E0472")]
 pub struct InlineAsmUnsupportedTarget {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::att_syntax_only_x86)]
 pub struct AttSyntaxOnlyX86 {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::abi_specified_multiple_times)]
 pub struct AbiSpecifiedMultipleTimes {
     #[primary_span]
@@ -175,14 +189,14 @@ pub struct AbiSpecifiedMultipleTimes {
     pub equivalent: Option<()>,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::clobber_abi_not_supported)]
 pub struct ClobberAbiNotSupported {
     #[primary_span]
     pub abi_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[note]
 #[diag(ast_lowering::invalid_abi_clobber_abi)]
 pub struct InvalidAbiClobberAbi {
@@ -191,7 +205,7 @@ pub struct InvalidAbiClobberAbi {
     pub supported_abis: String,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::invalid_register)]
 pub struct InvalidRegister<'a> {
     #[primary_span]
@@ -200,7 +214,7 @@ pub struct InvalidRegister<'a> {
     pub error: &'a str,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::invalid_register_class)]
 pub struct InvalidRegisterClass<'a> {
     #[primary_span]
@@ -209,7 +223,7 @@ pub struct InvalidRegisterClass<'a> {
     pub error: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_lowering::invalid_asm_template_modifier_reg_class)]
 pub struct InvalidAsmTemplateModifierRegClass {
     #[primary_span]
@@ -221,7 +235,7 @@ pub struct InvalidAsmTemplateModifierRegClass {
     pub sub: InvalidAsmTemplateModifierRegClassSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum InvalidAsmTemplateModifierRegClassSub {
     #[note(ast_lowering::support_modifiers)]
     SupportModifier { class_name: Symbol, modifiers: String },
@@ -229,7 +243,7 @@ pub enum InvalidAsmTemplateModifierRegClassSub {
     DoesNotSupportModifier { class_name: Symbol },
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::invalid_asm_template_modifier_const)]
 pub struct InvalidAsmTemplateModifierConst {
     #[primary_span]
@@ -239,7 +253,7 @@ pub struct InvalidAsmTemplateModifierConst {
     pub op_span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::invalid_asm_template_modifier_sym)]
 pub struct InvalidAsmTemplateModifierSym {
     #[primary_span]
@@ -249,7 +263,7 @@ pub struct InvalidAsmTemplateModifierSym {
     pub op_span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::register_class_only_clobber)]
 pub struct RegisterClassOnlyClobber {
     #[primary_span]
@@ -257,7 +271,7 @@ pub struct RegisterClassOnlyClobber {
     pub reg_class_name: Symbol,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::register_conflict)]
 pub struct RegisterConflict<'a> {
     #[primary_span]
@@ -271,7 +285,7 @@ pub struct RegisterConflict<'a> {
     pub in_out: Option<Span>,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[help]
 #[diag(ast_lowering::sub_tuple_binding)]
 pub struct SubTupleBinding<'a> {
@@ -288,7 +302,7 @@ pub struct SubTupleBinding<'a> {
     pub ctx: &'a str,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::extra_double_dot)]
 pub struct ExtraDoubleDot<'a> {
     #[primary_span]
@@ -299,7 +313,7 @@ pub struct ExtraDoubleDot<'a> {
     pub ctx: &'a str,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[note]
 #[diag(ast_lowering::misplaced_double_dot)]
 pub struct MisplacedDoubleDot {
@@ -307,30 +321,41 @@ pub struct MisplacedDoubleDot {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::misplaced_relax_trait_bound)]
 pub struct MisplacedRelaxTraitBound {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::not_supported_for_lifetime_binder_async_closure)]
 pub struct NotSupportedForLifetimeBinderAsyncClosure {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::arbitrary_expression_in_pattern)]
 pub struct ArbitraryExpressionInPattern {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic, Clone, Copy)]
+#[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering::inclusive_range_with_no_end)]
 pub struct InclusiveRangeWithNoEnd {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic, Clone, Copy)]
+#[diag(ast_lowering::trait_fn_async, code = "E0706")]
+#[note]
+#[note(ast_lowering::note2)]
+pub struct TraitFnAsync {
+    #[primary_span]
+    pub fn_span: Span,
+    #[label]
+    pub span: Span,
+}
diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 176047616881..94137391568c 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -7,7 +7,6 @@ use super::errors::{
 use super::ResolverAstLoweringExt;
 use super::{ImplTraitContext, LoweringContext, ParamMode, ParenthesizedGenericArgs};
 use crate::{FnDeclKind, ImplTraitPosition};
-
 use rustc_ast::attr;
 use rustc_ast::ptr::P as AstP;
 use rustc_ast::*;
@@ -18,6 +17,7 @@ use rustc_hir::definitions::DefPathData;
 use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::DUMMY_SP;
+use thin_vec::thin_vec;
 
 impl<'hir> LoweringContext<'_, 'hir> {
     fn lower_exprs(&mut self, exprs: &[AstP<Expr>]) -> &'hir [hir::Expr<'hir>] {
@@ -66,12 +66,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         seg,
                         ParamMode::Optional,
                         ParenthesizedGenericArgs::Err,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     ));
-                    let args = self.arena.alloc_from_iter(
-                        [&*receiver].into_iter().chain(args.iter()).map(|x| self.lower_expr_mut(x)),
-                    );
-                    hir::ExprKind::MethodCall(hir_seg, args, self.lower_span(span))
+                    let receiver = self.lower_expr(receiver);
+                    let args =
+                        self.arena.alloc_from_iter(args.iter().map(|x| self.lower_expr_mut(x)));
+                    hir::ExprKind::MethodCall(hir_seg, receiver, args, self.lower_span(span))
                 }
                 ExprKind::Binary(binop, ref lhs, ref rhs) => {
                     let binop = self.lower_binop(binop);
@@ -90,13 +90,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 ExprKind::Cast(ref expr, ref ty) => {
                     let expr = self.lower_expr(expr);
                     let ty =
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                        self.lower_ty(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                     hir::ExprKind::Cast(expr, ty)
                 }
                 ExprKind::Type(ref expr, ref ty) => {
                     let expr = self.lower_expr(expr);
                     let ty =
-                        self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                        self.lower_ty(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                     hir::ExprKind::Type(expr, ty)
                 }
                 ExprKind::AddrOf(k, m, ref ohs) => {
@@ -146,13 +146,19 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         |this| this.with_new_scopes(|this| this.lower_block_expr(block)),
                     ),
                 ExprKind::Await(ref expr) => {
-                    let span = if expr.span.hi() < e.span.hi() {
-                        expr.span.shrink_to_hi().with_hi(e.span.hi())
+                    let dot_await_span = if expr.span.hi() < e.span.hi() {
+                        let span_with_whitespace = self
+                            .tcx
+                            .sess
+                            .source_map()
+                            .span_extend_while(expr.span, char::is_whitespace)
+                            .unwrap_or(expr.span);
+                        span_with_whitespace.shrink_to_hi().with_hi(e.span.hi())
                     } else {
                         // this is a recovered `await expr`
                         e.span
                     };
-                    self.lower_expr_await(span, expr)
+                    self.lower_expr_await(dot_await_span, expr)
                 }
                 ExprKind::Closure(
                     ref binder,
@@ -219,7 +225,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     );
                     hir::ExprKind::Path(qpath)
                 }
@@ -253,7 +259,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             &se.qself,
                             &se.path,
                             ParamMode::Optional,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                            &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         )),
                         self.arena
                             .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
@@ -353,7 +359,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let node_id = self.next_node_id();
 
                 // Add a definition for the in-band const def.
-                self.create_def(parent_def_id, node_id, DefPathData::AnonConst);
+                self.create_def(parent_def_id.def_id, node_id, DefPathData::AnonConst);
 
                 let anon_const = AnonConst { id: node_id, value: arg };
                 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
@@ -552,7 +558,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     ) -> hir::ExprKind<'hir> {
         let output = match ret_ty {
             Some(ty) => hir::FnRetTy::Return(
-                self.lower_ty(&ty, ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock)),
+                self.lower_ty(&ty, &ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock)),
             ),
             None => hir::FnRetTy::DefaultReturn(self.lower_span(span)),
         };
@@ -577,7 +583,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let (pat, task_context_hid) = self.pat_ident_binding_mode(
             span,
             Ident::with_dummy_span(sym::_task_context),
-            hir::BindingAnnotation::Mutable,
+            hir::BindingAnnotation::MUT,
         );
         let param = hir::Param {
             hir_id: self.next_id(),
@@ -671,7 +677,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         // this name to identify what is being awaited by a suspended async functions.
         let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
         let (awaitee_pat, awaitee_pat_hid) =
-            self.pat_ident_binding_mode(span, awaitee_ident, hir::BindingAnnotation::Mutable);
+            self.pat_ident_binding_mode(span, awaitee_ident, hir::BindingAnnotation::MUT);
 
         let task_context_ident = Ident::with_dummy_span(sym::_task_context);
 
@@ -849,7 +855,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
         // Lower outside new scope to preserve `is_in_loop_condition`.
-        let fn_decl = self.lower_fn_decl(decl, None, FnDeclKind::Closure, None);
+        let fn_decl = self.lower_fn_decl(decl, None, fn_decl_span, FnDeclKind::Closure, None);
 
         let c = self.arena.alloc(hir::Closure {
             binder: binder_clause,
@@ -949,11 +955,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
         });
 
         let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
-
         // We need to lower the declaration outside the new scope, because we
         // have to conserve the state of being inside a loop condition for the
         // closure argument types.
-        let fn_decl = self.lower_fn_decl(&outer_decl, None, FnDeclKind::Closure, None);
+        let fn_decl =
+            self.lower_fn_decl(&outer_decl, None, fn_decl_span, FnDeclKind::Closure, None);
 
         let c = self.arena.alloc(hir::Closure {
             binder: binder_clause,
@@ -1123,11 +1129,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     );
                     // Destructure like a tuple struct.
-                    let tuple_struct_pat =
-                        hir::PatKind::TupleStruct(qpath, pats, rest.map(|r| r.0));
+                    let tuple_struct_pat = hir::PatKind::TupleStruct(
+                        qpath,
+                        pats,
+                        hir::DotDotPos::new(rest.map(|r| r.0)),
+                    );
                     return self.pat_without_dbm(lhs.span, tuple_struct_pat);
                 }
             }
@@ -1139,7 +1148,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         qself,
                         path,
                         ParamMode::Optional,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                        &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                     );
                     // Destructure like a unit struct.
                     let unit_struct_pat = hir::PatKind::Path(qpath);
@@ -1163,7 +1172,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     &se.qself,
                     &se.path,
                     ParamMode::Optional,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                 );
                 let fields_omitted = match &se.rest {
                     StructRest::Base(e) => {
@@ -1182,13 +1191,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
             ExprKind::Tup(elements) => {
                 let (pats, rest) =
                     self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
-                let tuple_pat = hir::PatKind::Tuple(pats, rest.map(|r| r.0));
+                let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
                 return self.pat_without_dbm(lhs.span, tuple_pat);
             }
             ExprKind::Paren(e) => {
                 // We special-case `(..)` for consistency with patterns.
                 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
-                    let tuple_pat = hir::PatKind::Tuple(&[], Some(0));
+                    let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
                     return self.pat_without_dbm(lhs.span, tuple_pat);
                 } else {
                     return self.destructure_assign_mut(e, eq_sign_span, assignments);
@@ -1433,7 +1442,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         // `mut iter`
         let iter = Ident::with_dummy_span(sym::iter);
         let (iter_pat, iter_pat_nid) =
-            self.pat_ident_binding_mode(head_span, iter, hir::BindingAnnotation::Mutable);
+            self.pat_ident_binding_mode(head_span, iter, hir::BindingAnnotation::MUT);
 
         // `match Iterator::next(&mut iter) { ... }`
         let match_expr = {
@@ -1539,9 +1548,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let uc_nested = attr::mk_nested_word_item(uc_ident);
                 attr::mk_list_item(allow_ident, vec![uc_nested])
             };
-            attr::mk_attr_outer(allow)
+            attr::mk_attr_outer(&self.tcx.sess.parse_sess.attr_id_generator, allow)
         };
-        let attrs: AttrVec = vec![attr].into();
+        let attrs: AttrVec = thin_vec![attr];
 
         // `ControlFlow::Continue(val) => #[allow(unreachable_code)] val,`
         let continue_arm = {
@@ -1776,12 +1785,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
         binding: hir::HirId,
         attrs: AttrVec,
     ) -> hir::Expr<'hir> {
+        let hir_id = self.next_id();
+        let res = Res::Local(binding);
         let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
             None,
             self.arena.alloc(hir::Path {
                 span: self.lower_span(span),
-                res: Res::Local(binding),
-                segments: arena_vec![self; hir::PathSegment::from_ident(ident)],
+                res,
+                segments: arena_vec![self; hir::PathSegment::new(ident, hir_id, res)],
             }),
         ));
 
diff --git a/compiler/rustc_ast_lowering/src/index.rs b/compiler/rustc_ast_lowering/src/index.rs
index 2b7431f09905..6d7167963433 100644
--- a/compiler/rustc_ast_lowering/src/index.rs
+++ b/compiler/rustc_ast_lowering/src/index.rs
@@ -11,8 +11,6 @@ use rustc_session::Session;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{Span, DUMMY_SP};
 
-use tracing::debug;
-
 /// A visitor that walks over the HIR and collects `Node`s into a HIR map.
 pub(super) struct NodeCollector<'a, 'hir> {
     /// Source map
@@ -26,12 +24,12 @@ pub(super) struct NodeCollector<'a, 'hir> {
     /// The parent of this node
     parent_node: hir::ItemLocalId,
 
-    owner: LocalDefId,
+    owner: OwnerId,
 
     definitions: &'a definitions::Definitions,
 }
 
-#[tracing::instrument(level = "debug", skip(sess, definitions, bodies))]
+#[instrument(level = "debug", skip(sess, definitions, bodies))]
 pub(super) fn index_hir<'hir>(
     sess: &Session,
     definitions: &definitions::Definitions,
@@ -67,10 +65,11 @@ pub(super) fn index_hir<'hir>(
 }
 
 impl<'a, 'hir> NodeCollector<'a, 'hir> {
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn insert(&mut self, span: Span, hir_id: HirId, node: Node<'hir>) {
         debug_assert_eq!(self.owner, hir_id.owner);
         debug_assert_ne!(hir_id.local_id.as_u32(), 0);
+        debug_assert_ne!(hir_id.local_id, self.parent_node);
 
         // Make sure that the DepNode of some node coincides with the HirId
         // owner of that node.
@@ -82,9 +81,9 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
                      current_dep_node_owner={} ({:?}), hir_id.owner={} ({:?})",
                     self.source_map.span_to_diagnostic_string(span),
                     node,
-                    self.definitions.def_path(self.owner).to_string_no_crate_verbose(),
+                    self.definitions.def_path(self.owner.def_id).to_string_no_crate_verbose(),
                     self.owner,
-                    self.definitions.def_path(hir_id.owner).to_string_no_crate_verbose(),
+                    self.definitions.def_path(hir_id.owner.def_id).to_string_no_crate_verbose(),
                     hir_id.owner,
                 )
             }
@@ -113,19 +112,19 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
 
     fn visit_nested_item(&mut self, item: ItemId) {
         debug!("visit_nested_item: {:?}", item);
-        self.insert_nested(item.def_id);
+        self.insert_nested(item.def_id.def_id);
     }
 
     fn visit_nested_trait_item(&mut self, item_id: TraitItemId) {
-        self.insert_nested(item_id.def_id);
+        self.insert_nested(item_id.def_id.def_id);
     }
 
     fn visit_nested_impl_item(&mut self, item_id: ImplItemId) {
-        self.insert_nested(item_id.def_id);
+        self.insert_nested(item_id.def_id.def_id);
     }
 
     fn visit_nested_foreign_item(&mut self, foreign_id: ForeignItemId) {
-        self.insert_nested(foreign_id.def_id);
+        self.insert_nested(foreign_id.def_id.def_id);
     }
 
     fn visit_nested_body(&mut self, id: BodyId) {
@@ -142,7 +141,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_item(&mut self, i: &'hir Item<'hir>) {
         debug_assert_eq!(i.def_id, self.owner);
         self.with_parent(i.hir_id(), |this| {
@@ -156,7 +155,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_foreign_item(&mut self, fi: &'hir ForeignItem<'hir>) {
         debug_assert_eq!(fi.def_id, self.owner);
         self.with_parent(fi.hir_id(), |this| {
@@ -175,7 +174,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         })
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_trait_item(&mut self, ti: &'hir TraitItem<'hir>) {
         debug_assert_eq!(ti.def_id, self.owner);
         self.with_parent(ti.hir_id(), |this| {
@@ -183,7 +182,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_impl_item(&mut self, ii: &'hir ImplItem<'hir>) {
         debug_assert_eq!(ii.def_id, self.owner);
         self.with_parent(ii.hir_id(), |this| {
@@ -247,11 +246,9 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'hir PathSegment<'hir>) {
-        if let Some(hir_id) = path_segment.hir_id {
-            self.insert(path_span, hir_id, Node::PathSegment(path_segment));
-        }
-        intravisit::walk_path_segment(self, path_span, path_segment);
+    fn visit_path_segment(&mut self, path_segment: &'hir PathSegment<'hir>) {
+        self.insert(path_segment.ident.span, path_segment.hir_id, Node::PathSegment(path_segment));
+        intravisit::walk_path_segment(self, path_segment);
     }
 
     fn visit_ty(&mut self, ty: &'hir Ty<'hir>) {
@@ -283,12 +280,12 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         fk: intravisit::FnKind<'hir>,
         fd: &'hir FnDecl<'hir>,
         b: BodyId,
-        s: Span,
+        _: Span,
         id: HirId,
     ) {
         assert_eq!(self.owner, id.owner);
         assert_eq!(self.parent_node, id.local_id);
-        intravisit::walk_fn(self, fk, fd, b, s, id);
+        intravisit::walk_fn(self, fk, fd, b, id);
     }
 
     fn visit_block(&mut self, block: &'hir Block<'hir>) {
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
index fd338ffc0c5e..d9b18d68e537 100644
--- a/compiler/rustc_ast_lowering/src/item.rs
+++ b/compiler/rustc_ast_lowering/src/item.rs
@@ -1,6 +1,6 @@
-use super::errors::{InvalidAbi, MisplacedRelaxTraitBound};
+use super::errors::{InvalidAbi, InvalidAbiSuggestion, MisplacedRelaxTraitBound};
 use super::ResolverAstLoweringExt;
-use super::{AstOwner, ImplTraitContext, ImplTraitPosition};
+use super::{Arena, AstOwner, ImplTraitContext, ImplTraitPosition};
 use super::{FnDeclKind, LoweringContext, ParamMode};
 
 use rustc_ast::ptr::P;
@@ -14,9 +14,10 @@ use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
 use rustc_hir::PredicateOrigin;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::ty::{DefIdTree, ResolverAstLowering, TyCtxt};
+use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::Span;
+use rustc_span::{Span, Symbol};
 use rustc_target::spec::abi;
 use smallvec::{smallvec, SmallVec};
 
@@ -25,6 +26,7 @@ use std::iter;
 pub(super) struct ItemLowerer<'a, 'hir> {
     pub(super) tcx: TyCtxt<'hir>,
     pub(super) resolver: &'a mut ResolverAstLowering,
+    pub(super) ast_arena: &'a Arena<'static>,
     pub(super) ast_index: &'a IndexVec<LocalDefId, AstOwner<'a>>,
     pub(super) owners: &'a mut IndexVec<LocalDefId, hir::MaybeOwner<&'hir hir::OwnerInfo<'hir>>>,
 }
@@ -60,12 +62,13 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
             tcx: self.tcx,
             resolver: self.resolver,
             arena: self.tcx.hir_arena,
+            ast_arena: self.ast_arena,
 
             // HirId handling.
             bodies: Vec::new(),
             attrs: SortedMap::default(),
             children: FxHashMap::default(),
-            current_hir_id_owner: CRATE_DEF_ID,
+            current_hir_id_owner: hir::CRATE_OWNER_ID,
             item_local_id_counter: hir::ItemLocalId::new(0),
             node_id_to_local_id: Default::default(),
             local_id_to_def_id: SortedMap::new(),
@@ -85,6 +88,7 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
             allow_try_trait: Some([sym::try_trait_v2, sym::yeet_desugar_details][..].into()),
             allow_gen_future: Some([sym::gen_future][..].into()),
             allow_into_future: Some([sym::into_future][..].into()),
+            generics_def_id_map: Default::default(),
         };
         lctx.with_hir_id_owner(owner, |lctx| f(lctx));
 
@@ -120,7 +124,7 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
         self.with_lctx(CRATE_NODE_ID, |lctx| {
             let module = lctx.lower_mod(&c.items, &c.spans);
             lctx.lower_attrs(hir::CRATE_HIR_ID, &c.attrs);
-            hir::OwnerNode::Crate(lctx.arena.alloc(module))
+            hir::OwnerNode::Crate(module)
         })
     }
 
@@ -158,18 +162,23 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
 }
 
 impl<'hir> LoweringContext<'_, 'hir> {
-    pub(super) fn lower_mod(&mut self, items: &[P<Item>], spans: &ModSpans) -> hir::Mod<'hir> {
-        hir::Mod {
+    pub(super) fn lower_mod(
+        &mut self,
+        items: &[P<Item>],
+        spans: &ModSpans,
+    ) -> &'hir hir::Mod<'hir> {
+        self.arena.alloc(hir::Mod {
             spans: hir::ModSpans {
                 inner_span: self.lower_span(spans.inner_span),
                 inject_use_span: self.lower_span(spans.inject_use_span),
             },
             item_ids: self.arena.alloc_from_iter(items.iter().flat_map(|x| self.lower_item_ref(x))),
-        }
+        })
     }
 
     pub(super) fn lower_item_ref(&mut self, i: &Item) -> SmallVec<[hir::ItemId; 1]> {
-        let mut node_ids = smallvec![hir::ItemId { def_id: self.local_def_id(i.id) }];
+        let mut node_ids =
+            smallvec![hir::ItemId { def_id: hir::OwnerId { def_id: self.local_def_id(i.id) } }];
         if let ItemKind::Use(ref use_tree) = &i.kind {
             self.lower_item_id_use_tree(use_tree, i.id, &mut node_ids);
         }
@@ -185,7 +194,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
         match tree.kind {
             UseTreeKind::Nested(ref nested_vec) => {
                 for &(ref nested, id) in nested_vec {
-                    vec.push(hir::ItemId { def_id: self.local_def_id(id) });
+                    vec.push(hir::ItemId {
+                        def_id: hir::OwnerId { def_id: self.local_def_id(id) },
+                    });
                     self.lower_item_id_use_tree(nested, id, vec);
                 }
             }
@@ -194,7 +205,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 for (_, &id) in
                     iter::zip(self.expect_full_res_from_use(base_id).skip(1), &[id1, id2])
                 {
-                    vec.push(hir::ItemId { def_id: self.local_def_id(id) });
+                    vec.push(hir::ItemId {
+                        def_id: hir::OwnerId { def_id: self.local_def_id(id) },
+                    });
                 }
             }
         }
@@ -259,10 +272,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     let body_id =
                         this.lower_maybe_async_body(span, &decl, asyncness, body.as_deref());
 
-                    let itctx = ImplTraitContext::Universal;
-                    let (generics, decl) = this.lower_generics(generics, id, itctx, |this| {
+                    let mut itctx = ImplTraitContext::Universal;
+                    let (generics, decl) = this.lower_generics(generics, id, &mut itctx, |this| {
                         let ret_id = asyncness.opt_return_id();
-                        this.lower_fn_decl(&decl, Some(id), FnDeclKind::Fn, ret_id)
+                        this.lower_fn_decl(&decl, Some(id), fn_sig_span, FnDeclKind::Fn, ret_id)
                     });
                     let sig = hir::FnSig {
                         decl,
@@ -306,8 +319,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, ty) = self.lower_generics(
                     &generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
-                    |this| this.lower_ty(ty, ImplTraitContext::TypeAliasesOpaqueTy),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    |this| this.lower_ty(ty, &ImplTraitContext::TypeAliasesOpaqueTy),
                 );
                 hir::ItemKind::TyAlias(ty, generics)
             }
@@ -319,7 +332,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, ty) = self.lower_generics(
                     &generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| this.arena.alloc(this.ty(span, hir::TyKind::Err)),
                 );
                 hir::ItemKind::TyAlias(ty, generics)
@@ -328,7 +341,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, variants) = self.lower_generics(
                     generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
                         this.arena.alloc_from_iter(
                             enum_definition.variants.iter().map(|x| this.lower_variant(x)),
@@ -341,7 +354,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, struct_def) = self.lower_generics(
                     generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| this.lower_variant_data(hir_id, struct_def),
                 );
                 hir::ItemKind::Struct(struct_def, generics)
@@ -350,7 +363,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, vdata) = self.lower_generics(
                     generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| this.lower_variant_data(hir_id, vdata),
                 );
                 hir::ItemKind::Union(vdata, generics)
@@ -378,18 +391,18 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 // method, it will not be considered an in-band
                 // lifetime to be added, but rather a reference to a
                 // parent lifetime.
-                let itctx = ImplTraitContext::Universal;
+                let mut itctx = ImplTraitContext::Universal;
                 let (generics, (trait_ref, lowered_ty)) =
-                    self.lower_generics(ast_generics, id, itctx, |this| {
+                    self.lower_generics(ast_generics, id, &mut itctx, |this| {
                         let trait_ref = trait_ref.as_ref().map(|trait_ref| {
                             this.lower_trait_ref(
                                 trait_ref,
-                                ImplTraitContext::Disallowed(ImplTraitPosition::Trait),
+                                &ImplTraitContext::Disallowed(ImplTraitPosition::Trait),
                             )
                         });
 
                         let lowered_ty = this
-                            .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                            .lower_ty(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
 
                         (trait_ref, lowered_ty)
                     });
@@ -428,11 +441,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, (unsafety, items, bounds)) = self.lower_generics(
                     generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
                         let bounds = this.lower_param_bounds(
                             bounds,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
+                            &ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
                         );
                         let items = this.arena.alloc_from_iter(
                             items.iter().map(|item| this.lower_trait_item_ref(item)),
@@ -447,11 +460,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, bounds) = self.lower_generics(
                     generics,
                     id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
                         this.lower_param_bounds(
                             bounds,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
+                            &ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
                         )
                     },
                 );
@@ -474,7 +487,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         span: Span,
         body: Option<&Expr>,
     ) -> (&'hir hir::Ty<'hir>, hir::BodyId) {
-        let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+        let ty = self.lower_ty(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
         (ty, self.lower_const_body(span, body))
     }
 
@@ -545,7 +558,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         }
 
                         let item = hir::Item {
-                            def_id: new_id,
+                            def_id: hir::OwnerId { def_id: new_id },
                             ident: this.lower_ident(ident),
                             kind,
                             vis_span,
@@ -619,7 +632,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         }
 
                         let item = hir::Item {
-                            def_id: new_hir_id,
+                            def_id: hir::OwnerId { def_id: new_hir_id },
                             ident: this.lower_ident(ident),
                             kind,
                             vis_span,
@@ -647,12 +660,18 @@ impl<'hir> LoweringContext<'_, 'hir> {
             kind: match i.kind {
                 ForeignItemKind::Fn(box Fn { ref sig, ref generics, .. }) => {
                     let fdec = &sig.decl;
-                    let itctx = ImplTraitContext::Universal;
+                    let mut itctx = ImplTraitContext::Universal;
                     let (generics, (fn_dec, fn_args)) =
-                        self.lower_generics(generics, i.id, itctx, |this| {
+                        self.lower_generics(generics, i.id, &mut itctx, |this| {
                             (
                                 // Disallow `impl Trait` in foreign items.
-                                this.lower_fn_decl(fdec, None, FnDeclKind::ExternFn, None),
+                                this.lower_fn_decl(
+                                    fdec,
+                                    None,
+                                    sig.span,
+                                    FnDeclKind::ExternFn,
+                                    None,
+                                ),
                                 this.lower_fn_params_to_names(fdec),
                             )
                         });
@@ -661,7 +680,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ForeignItemKind::Static(ref t, m, _) => {
                     let ty =
-                        self.lower_ty(t, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                        self.lower_ty(t, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                     hir::ForeignItemKind::Static(ty, m)
                 }
                 ForeignItemKind::TyAlias(..) => hir::ForeignItemKind::Type,
@@ -675,7 +694,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemRef {
         hir::ForeignItemRef {
-            id: hir::ForeignItemId { def_id: self.local_def_id(i.id) },
+            id: hir::ForeignItemId { def_id: hir::OwnerId { def_id: self.local_def_id(i.id) } },
             ident: self.lower_ident(i.ident),
             span: self.lower_span(i.span),
         }
@@ -729,11 +748,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 qself,
                 path,
                 ParamMode::ExplicitNamed, // no `'_` in declarations (Issue #61124)
-                ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
             );
             self.arena.alloc(t)
         } else {
-            self.lower_ty(&f.ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type))
+            self.lower_ty(&f.ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type))
         };
         let hir_id = self.lower_node_id(f.id);
         self.lower_attrs(hir_id, &f.attrs);
@@ -756,14 +775,20 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         let (generics, kind, has_default) = match i.kind {
             AssocItemKind::Const(_, ref ty, ref default) => {
-                let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                let ty = self.lower_ty(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                 let body = default.as_ref().map(|x| self.lower_const_body(i.span, Some(x)));
                 (hir::Generics::empty(), hir::TraitItemKind::Const(ty, body), body.is_some())
             }
             AssocItemKind::Fn(box Fn { ref sig, ref generics, body: None, .. }) => {
+                let asyncness = sig.header.asyncness;
                 let names = self.lower_fn_params_to_names(&sig.decl);
-                let (generics, sig) =
-                    self.lower_method_sig(generics, sig, i.id, FnDeclKind::Trait, None);
+                let (generics, sig) = self.lower_method_sig(
+                    generics,
+                    sig,
+                    i.id,
+                    FnDeclKind::Trait,
+                    asyncness.opt_return_id(),
+                );
                 (generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Required(names)), false)
             }
             AssocItemKind::Fn(box Fn { ref sig, ref generics, body: Some(ref body), .. }) => {
@@ -791,15 +816,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let (generics, kind) = self.lower_generics(
                     &generics,
                     i.id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| {
                         let ty = ty.as_ref().map(|x| {
-                            this.lower_ty(x, ImplTraitContext::Disallowed(ImplTraitPosition::Type))
+                            this.lower_ty(x, &ImplTraitContext::Disallowed(ImplTraitPosition::Type))
                         });
                         hir::TraitItemKind::Type(
                             this.lower_param_bounds(
                                 bounds,
-                                ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                                &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                             ),
                             ty,
                         )
@@ -831,7 +856,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
             AssocItemKind::MacCall(..) => unimplemented!(),
         };
-        let id = hir::TraitItemId { def_id: self.local_def_id(i.id) };
+        let id = hir::TraitItemId { def_id: hir::OwnerId { def_id: self.local_def_id(i.id) } };
         hir::TraitItemRef {
             id,
             ident: self.lower_ident(i.ident),
@@ -852,7 +877,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         let (generics, kind) = match &i.kind {
             AssocItemKind::Const(_, ty, expr) => {
-                let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                let ty = self.lower_ty(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                 (
                     hir::Generics::empty(),
                     hir::ImplItemKind::Const(ty, self.lower_const_body(i.span, expr.as_deref())),
@@ -879,14 +904,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 self.lower_generics(
                     &generics,
                     i.id,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Generic),
                     |this| match ty {
                         None => {
                             let ty = this.arena.alloc(this.ty(i.span, hir::TyKind::Err));
                             hir::ImplItemKind::TyAlias(ty)
                         }
                         Some(ty) => {
-                            let ty = this.lower_ty(ty, ImplTraitContext::TypeAliasesOpaqueTy);
+                            let ty = this.lower_ty(ty, &ImplTraitContext::TypeAliasesOpaqueTy);
                             hir::ImplItemKind::TyAlias(ty)
                         }
                     },
@@ -911,7 +936,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_impl_item_ref(&mut self, i: &AssocItem) -> hir::ImplItemRef {
         hir::ImplItemRef {
-            id: hir::ImplItemId { def_id: self.local_def_id(i.id) },
+            id: hir::ImplItemId { def_id: hir::OwnerId { def_id: self.local_def_id(i.id) } },
             ident: self.lower_ident(i.ident),
             span: self.lower_span(i.span),
             kind: match &i.kind {
@@ -947,7 +972,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
         params: &'hir [hir::Param<'hir>],
         value: hir::Expr<'hir>,
     ) -> hir::BodyId {
-        let body = hir::Body { generator_kind: self.generator_kind, params, value };
+        let body = hir::Body {
+            generator_kind: self.generator_kind,
+            params,
+            value: self.arena.alloc(value),
+        };
         let id = body.id();
         debug_assert_eq!(id.hir_id.owner, self.current_hir_id_owner);
         self.bodies.push((id.hir_id.local_id, self.arena.alloc(body)));
@@ -1026,9 +1055,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
         asyncness: Async,
         body: Option<&Block>,
     ) -> hir::BodyId {
-        let closure_id = match asyncness {
-            Async::Yes { closure_id, .. } => closure_id,
-            Async::No => return self.lower_fn_body_block(span, decl, body),
+        let (closure_id, body) = match (asyncness, body) {
+            (Async::Yes { closure_id, .. }, Some(body)) => (closure_id, body),
+            _ => return self.lower_fn_body_block(span, decl, body),
         };
 
         self.lower_body(|this| {
@@ -1074,12 +1103,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 // Check if this is a binding pattern, if so, we can optimize and avoid adding a
                 // `let <pat> = __argN;` statement. In this case, we do not rename the parameter.
                 let (ident, is_simple_parameter) = match parameter.pat.kind {
-                    hir::PatKind::Binding(
-                        hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Mutable,
-                        _,
-                        ident,
-                        _,
-                    ) => (ident, true),
+                    hir::PatKind::Binding(hir::BindingAnnotation(ByRef::No, _), _, ident, _) => {
+                        (ident, true)
+                    }
                     // For `ref mut` or wildcard arguments, we can't reuse the binding, but
                     // we can keep the same name for the parameter.
                     // This lets rustdoc render it correctly in documentation.
@@ -1144,7 +1170,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     let (move_pat, move_id) = this.pat_ident_binding_mode(
                         desugared_span,
                         ident,
-                        hir::BindingAnnotation::Mutable,
+                        hir::BindingAnnotation::MUT,
                     );
                     let move_expr = this.expr_ident(desugared_span, ident, new_parameter_id);
                     let move_stmt = this.stmt_let_pat(
@@ -1173,16 +1199,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 parameters.push(new_parameter);
             }
 
-            let body_span = body.map_or(span, |b| b.span);
             let async_expr = this.make_async_expr(
                 CaptureBy::Value,
                 closure_id,
                 None,
-                body_span,
+                body.span,
                 hir::AsyncGeneratorKind::Fn,
                 |this| {
                     // Create a block from the user's function body:
-                    let user_body = this.lower_block_expr_opt(body_span, body);
+                    let user_body = this.lower_block_expr(body);
 
                     // Transform into `drop-temps { <user-body> }`, an expression:
                     let desugared_span =
@@ -1214,7 +1239,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
             (
                 this.arena.alloc_from_iter(parameters),
-                this.expr(body_span, async_expr, AttrVec::new()),
+                this.expr(body.span, async_expr, AttrVec::new()),
             )
         })
     }
@@ -1225,12 +1250,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
         sig: &FnSig,
         id: NodeId,
         kind: FnDeclKind,
-        is_async: Option<NodeId>,
+        is_async: Option<(NodeId, Span)>,
     ) -> (&'hir hir::Generics<'hir>, hir::FnSig<'hir>) {
         let header = self.lower_fn_header(sig.header);
-        let itctx = ImplTraitContext::Universal;
-        let (generics, decl) = self.lower_generics(generics, id, itctx, |this| {
-            this.lower_fn_decl(&sig.decl, Some(id), kind, is_async)
+        let mut itctx = ImplTraitContext::Universal;
+        let (generics, decl) = self.lower_generics(generics, id, &mut itctx, |this| {
+            this.lower_fn_decl(&sig.decl, Some(id), sig.span, kind, is_async)
         });
         (generics, hir::FnSig { header, decl, span: self.lower_span(sig.span) })
     }
@@ -1260,10 +1285,19 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn error_on_invalid_abi(&self, abi: StrLit) {
+        let abi_names = abi::enabled_names(self.tcx.features(), abi.span)
+            .iter()
+            .map(|s| Symbol::intern(s))
+            .collect::<Vec<_>>();
+        let suggested_name = find_best_match_for_name(&abi_names, abi.symbol_unescaped, None);
         self.tcx.sess.emit_err(InvalidAbi {
+            abi: abi.symbol_unescaped,
             span: abi.span,
-            abi: abi.symbol,
-            valid_abis: abi::all_names().join(", "),
+            suggestion: suggested_name.map(|suggested_name| InvalidAbiSuggestion {
+                span: abi.span,
+                suggestion: format!("\"{suggested_name}\""),
+            }),
+            command: "rustc --print=calling-conventions".to_string(),
         });
     }
 
@@ -1295,7 +1329,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &mut self,
         generics: &Generics,
         parent_node_id: NodeId,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
         f: impl FnOnce(&mut Self) -> T,
     ) -> (&'hir hir::Generics<'hir>, T) {
         debug_assert!(self.impl_trait_defs.is_empty());
@@ -1400,7 +1434,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         id: NodeId,
         kind: &GenericParamKind,
         bounds: &[GenericBound],
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
         origin: PredicateOrigin,
     ) -> Option<hir::WherePredicate<'hir>> {
         // Do not create a clause if we do not have anything inside it.
@@ -1431,10 +1465,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
             GenericParamKind::Const { .. } => None,
             GenericParamKind::Type { .. } => {
                 let def_id = self.local_def_id(id).to_def_id();
+                let hir_id = self.next_id();
+                let res = Res::Def(DefKind::TyParam, def_id);
                 let ty_path = self.arena.alloc(hir::Path {
                     span: param_span,
-                    res: Res::Def(DefKind::TyParam, def_id),
-                    segments: self.arena.alloc_from_iter([hir::PathSegment::from_ident(ident)]),
+                    res,
+                    segments: self
+                        .arena
+                        .alloc_from_iter([hir::PathSegment::new(ident, hir_id, res)]),
                 });
                 let ty_id = self.next_id();
                 let bounded_ty =
@@ -1472,11 +1510,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }) => hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
                 bound_generic_params: self.lower_generic_params(bound_generic_params),
                 bounded_ty: self
-                    .lower_ty(bounded_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
+                    .lower_ty(bounded_ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
                 bounds: self.arena.alloc_from_iter(bounds.iter().map(|bound| {
                     self.lower_param_bound(
                         bound,
-                        ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
+                        &ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
                     )
                 })),
                 span: self.lower_span(span),
@@ -1491,16 +1529,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 lifetime: self.lower_lifetime(lifetime),
                 bounds: self.lower_param_bounds(
                     bounds,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Bound),
                 ),
                 in_where_clause: true,
             }),
             WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, span }) => {
                 hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
                     lhs_ty: self
-                        .lower_ty(lhs_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
+                        .lower_ty(lhs_ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
                     rhs_ty: self
-                        .lower_ty(rhs_ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
+                        .lower_ty(rhs_ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type)),
                     span: self.lower_span(span),
                 })
             }
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 30a87740c7f9..275ceed30d7d 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -32,7 +32,6 @@
 
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
@@ -42,8 +41,9 @@
 #[macro_use]
 extern crate tracing;
 
-use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait};
+use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait, TraitFnAsync};
 
+use rustc_arena::declare_arena;
 use rustc_ast::ptr::P;
 use rustc_ast::visit;
 use rustc_ast::{self as ast, *};
@@ -95,6 +95,13 @@ struct LoweringContext<'a, 'hir> {
     /// Used to allocate HIR nodes.
     arena: &'hir hir::Arena<'hir>,
 
+    /// Used to allocate temporary AST nodes for use during lowering.
+    /// This allows us to create "fake" AST -- these nodes can sometimes
+    /// be allocated on the stack, but other times we need them to live longer
+    /// than the current stack frame, so they can be collected into vectors
+    /// and things like that.
+    ast_arena: &'a Arena<'static>,
+
     /// Bodies inside the owner being lowered.
     bodies: Vec<(hir::ItemLocalId, &'hir hir::Body<'hir>)>,
     /// Attributes inside the owner being lowered.
@@ -118,7 +125,7 @@ struct LoweringContext<'a, 'hir> {
     is_in_trait_impl: bool,
     is_in_dyn_type: bool,
 
-    current_hir_id_owner: LocalDefId,
+    current_hir_id_owner: hir::OwnerId,
     item_local_id_counter: hir::ItemLocalId,
     local_id_to_def_id: SortedMap<ItemLocalId, LocalDefId>,
     trait_map: FxHashMap<ItemLocalId, Box<[TraitCandidate]>>,
@@ -132,8 +139,23 @@ struct LoweringContext<'a, 'hir> {
     allow_try_trait: Option<Lrc<[Symbol]>>,
     allow_gen_future: Option<Lrc<[Symbol]>>,
     allow_into_future: Option<Lrc<[Symbol]>>,
+
+    /// Mapping from generics `def_id`s to TAIT generics `def_id`s.
+    /// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
+    /// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
+    /// field from the original parameter 'a to the new parameter 'a1.
+    generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
 }
 
+declare_arena!([
+    [] tys: rustc_ast::Ty,
+    [] aba: rustc_ast::AngleBracketedArgs,
+    [] ptr: rustc_ast::PolyTraitRef,
+    // This _marker field is needed because `declare_arena` creates `Arena<'tcx>` and we need to
+    // use `'tcx`. If we don't have this we get a compile error.
+    [] _marker: std::marker::PhantomData<&'tcx ()>,
+]);
+
 trait ResolverAstLoweringExt {
     fn legacy_const_generic_args(&self, expr: &Expr) -> Option<Vec<usize>>;
     fn get_partial_res(&self, id: NodeId) -> Option<PartialRes>;
@@ -142,12 +164,6 @@ trait ResolverAstLoweringExt {
     fn get_lifetime_res(&self, id: NodeId) -> Option<LifetimeRes>;
     fn take_extra_lifetime_params(&mut self, id: NodeId) -> Vec<(Ident, NodeId, LifetimeRes)>;
     fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind;
-    /// Record the map from `from` local def id to `to` local def id, on `generics_def_id_map`
-    /// field.
-    fn record_def_id_remap(&mut self, from: LocalDefId, to: LocalDefId);
-    /// Get the previously recorded `to` local def id given the `from` local def id, obtained using
-    /// `generics_def_id_map` field.
-    fn get_remapped_def_id(&self, local_def_id: LocalDefId) -> LocalDefId;
 }
 
 impl ResolverAstLoweringExt for ResolverAstLowering {
@@ -215,41 +231,6 @@ impl ResolverAstLoweringExt for ResolverAstLowering {
     fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind {
         self.builtin_macro_kinds.get(&def_id).copied().unwrap_or(MacroKind::Bang)
     }
-
-    /// Push a remapping into the top-most map.
-    /// Panics if no map has been pushed.
-    /// Remapping is used when creating lowering `-> impl Trait` return
-    /// types to create the resulting opaque type.
-    #[tracing::instrument(level = "debug", skip(self))]
-    fn record_def_id_remap(&mut self, from: LocalDefId, to: LocalDefId) {
-        self.generics_def_id_map.last_mut().expect("no map pushed").insert(from, to);
-    }
-
-    fn get_remapped_def_id(&self, mut local_def_id: LocalDefId) -> LocalDefId {
-        // `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we
-        // push new mappings so we need to try first the latest mappings, hence `iter().rev()`.
-        //
-        // Consider:
-        //
-        // `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}`
-        //
-        // We would end with a generics_def_id_map like:
-        //
-        // `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]`
-        //
-        // for the opaque type generated on `impl Sized + 'b`, We want the result to be:
-        // impl_sized#'b, so iterating forward is the wrong thing to do.
-        for map in self.generics_def_id_map.iter().rev() {
-            if let Some(r) = map.get(&local_def_id) {
-                debug!("def_id_remapper: remapping from `{local_def_id:?}` to `{r:?}`");
-                local_def_id = *r;
-            } else {
-                debug!("def_id_remapper: no remapping for `{local_def_id:?}` found in map");
-            }
-        }
-
-        local_def_id
-    }
 }
 
 /// Context of `impl Trait` in code, which determines whether it is allowed in an HIR subtree,
@@ -270,6 +251,7 @@ enum ImplTraitContext {
     ReturnPositionOpaqueTy {
         /// Origin: Either OpaqueTyOrigin::FnReturn or OpaqueTyOrigin::AsyncFn,
         origin: hir::OpaqueTyOrigin,
+        in_trait: bool,
     },
     /// Impl trait in type aliases.
     TypeAliasesOpaqueTy,
@@ -329,7 +311,7 @@ impl std::fmt::Display for ImplTraitPosition {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq)]
 enum FnDeclKind {
     Fn,
     Inherent,
@@ -341,9 +323,20 @@ enum FnDeclKind {
 }
 
 impl FnDeclKind {
-    fn impl_trait_return_allowed(&self) -> bool {
+    fn impl_trait_allowed(&self, tcx: TyCtxt<'_>) -> bool {
         match self {
             FnDeclKind::Fn | FnDeclKind::Inherent => true,
+            FnDeclKind::Impl if tcx.features().return_position_impl_trait_in_trait => true,
+            FnDeclKind::Trait if tcx.features().return_position_impl_trait_in_trait => true,
+            _ => false,
+        }
+    }
+
+    fn async_fn_allowed(&self, tcx: TyCtxt<'_>) -> bool {
+        match self {
+            FnDeclKind::Fn | FnDeclKind::Inherent => true,
+            FnDeclKind::Impl if tcx.features().async_fn_in_trait => true,
+            FnDeclKind::Trait if tcx.features().async_fn_in_trait => true,
             _ => false,
         }
     }
@@ -436,10 +429,13 @@ pub fn lower_to_hir<'hir>(tcx: TyCtxt<'hir>, (): ()) -> hir::Crate<'hir> {
         tcx.definitions_untracked().def_index_count(),
     );
 
+    let ast_arena = Arena::default();
+
     for def_id in ast_index.indices() {
         item::ItemLowerer {
             tcx,
             resolver: &mut resolver,
+            ast_arena: &ast_arena,
             ast_index: &ast_index,
             owners: &mut owners,
         }
@@ -522,13 +518,41 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.resolver
             .node_id_to_def_id
             .get(&node)
-            .map(|local_def_id| self.resolver.get_remapped_def_id(*local_def_id))
+            .map(|local_def_id| self.get_remapped_def_id(*local_def_id))
     }
 
     fn local_def_id(&self, node: NodeId) -> LocalDefId {
         self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
     }
 
+    /// Get the previously recorded `to` local def id given the `from` local def id, obtained using
+    /// `generics_def_id_map` field.
+    fn get_remapped_def_id(&self, mut local_def_id: LocalDefId) -> LocalDefId {
+        // `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we
+        // push new mappings so we need to try first the latest mappings, hence `iter().rev()`.
+        //
+        // Consider:
+        //
+        // `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}`
+        //
+        // We would end with a generics_def_id_map like:
+        //
+        // `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]`
+        //
+        // for the opaque type generated on `impl Sized + 'b`, We want the result to be:
+        // impl_sized#'b, so iterating forward is the wrong thing to do.
+        for map in self.generics_def_id_map.iter().rev() {
+            if let Some(r) = map.get(&local_def_id) {
+                debug!("def_id_remapper: remapping from `{local_def_id:?}` to `{r:?}`");
+                local_def_id = *r;
+            } else {
+                debug!("def_id_remapper: no remapping for `{local_def_id:?}` found in map");
+            }
+        }
+
+        local_def_id
+    }
+
     /// Freshen the `LoweringContext` and ready it to lower a nested item.
     /// The lowered item is registered into `self.children`.
     ///
@@ -547,7 +571,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let current_node_ids = std::mem::take(&mut self.node_id_to_local_id);
         let current_id_to_def_id = std::mem::take(&mut self.local_id_to_def_id);
         let current_trait_map = std::mem::take(&mut self.trait_map);
-        let current_owner = std::mem::replace(&mut self.current_hir_id_owner, def_id);
+        let current_owner =
+            std::mem::replace(&mut self.current_hir_id_owner, hir::OwnerId { def_id });
         let current_local_counter =
             std::mem::replace(&mut self.item_local_id_counter, hir::ItemLocalId::new(1));
         let current_impl_trait_defs = std::mem::take(&mut self.impl_trait_defs);
@@ -562,7 +587,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         debug_assert_eq!(_old, None);
 
         let item = f(self);
-        debug_assert_eq!(def_id, item.def_id());
+        debug_assert_eq!(def_id, item.def_id().def_id);
         // `f` should have consumed all the elements in these vectors when constructing `item`.
         debug_assert!(self.impl_trait_defs.is_empty());
         debug_assert!(self.impl_trait_bounds.is_empty());
@@ -597,9 +622,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         remap: FxHashMap<LocalDefId, LocalDefId>,
         f: impl FnOnce(&mut Self) -> R,
     ) -> R {
-        self.resolver.generics_def_id_map.push(remap);
+        self.generics_def_id_map.push(remap);
         let res = f(self);
-        self.resolver.generics_def_id_map.pop();
+        self.generics_def_id_map.pop();
         res
     }
 
@@ -667,6 +692,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     /// actually used in the HIR, as that would trigger an assertion in the
     /// `HirIdValidator` later on, which makes sure that all `NodeId`s got mapped
     /// properly. Calling the method twice with the same `NodeId` is fine though.
+    #[instrument(level = "debug", skip(self), ret)]
     fn lower_node_id(&mut self, ast_node_id: NodeId) -> hir::HirId {
         assert_ne!(ast_node_id, DUMMY_NODE_ID);
 
@@ -700,6 +726,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     /// Generate a new `HirId` without a backing `NodeId`.
+    #[instrument(level = "debug", skip(self), ret)]
     fn next_id(&mut self) -> hir::HirId {
         let owner = self.current_hir_id_owner;
         let local_id = self.item_local_id_counter;
@@ -759,7 +786,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     /// Mark a span as relative to the current owning item.
     fn lower_span(&self, span: Span) -> Span {
         if self.tcx.sess.opts.unstable_opts.incremental_relative_spans {
-            span.with_parent(Some(self.current_hir_id_owner))
+            span.with_parent(Some(self.current_hir_id_owner.def_id))
         } else {
             // Do not make spans relative when not using incremental compilation.
             span
@@ -771,7 +798,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     /// Converts a lifetime into a new generic parameter.
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn lifetime_res_to_generic_param(
         &mut self,
         ident: Ident,
@@ -785,7 +812,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             LifetimeRes::Fresh { param, .. } => {
                 // Late resolution delegates to us the creation of the `LocalDefId`.
                 let _def_id = self.create_def(
-                    self.current_hir_id_owner,
+                    self.current_hir_id_owner.def_id,
                     param,
                     DefPathData::LifetimeNs(kw::UnderscoreLifetime),
                 );
@@ -815,7 +842,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     /// name resolver owing to lifetime elision; this also populates the resolver's node-id->def-id
     /// map, so that later calls to `opt_node_id_to_def_id` that refer to these extra lifetime
     /// parameters will be successful.
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     #[inline]
     fn lower_lifetime_binder(
         &mut self,
@@ -960,7 +987,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_assoc_ty_constraint(
         &mut self,
         constraint: &AssocConstraint,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::TypeBinding<'hir> {
         debug!("lower_assoc_ty_constraint(constraint={:?}, itctx={:?})", constraint, itctx);
         // lower generic arguments of identifier in constraint
@@ -971,18 +998,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 }
                 GenericArgs::Parenthesized(ref data) => {
                     self.emit_bad_parenthesized_trait_in_assoc_ty(data);
-                    self.lower_angle_bracketed_parameter_data(
-                        &data.as_angle_bracketed_args(),
-                        ParamMode::Explicit,
-                        itctx,
-                    )
-                    .0
+                    let aba = self.ast_arena.aba.alloc(data.as_angle_bracketed_args());
+                    self.lower_angle_bracketed_parameter_data(aba, ParamMode::Explicit, itctx).0
                 }
             };
             gen_args_ctor.into_generic_args(self)
         } else {
             self.arena.alloc(hir::GenericArgs::none())
         };
+        let itctx_tait = &ImplTraitContext::TypeAliasesOpaqueTy;
 
         let kind = match constraint.kind {
             AssocConstraintKind::Equality { ref term } => {
@@ -1020,9 +1044,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     // then to an opaque type).
                     //
                     // FIXME: this is only needed until `impl Trait` is allowed in type aliases.
-                    ImplTraitContext::Disallowed(_) if self.is_in_dyn_type => {
-                        (true, ImplTraitContext::TypeAliasesOpaqueTy)
-                    }
+                    ImplTraitContext::Disallowed(_) if self.is_in_dyn_type => (true, itctx_tait),
 
                     // We are in the parameter position, but not within a dyn type:
                     //
@@ -1040,19 +1062,21 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                     let parent_def_id = self.current_hir_id_owner;
                     let impl_trait_node_id = self.next_node_id();
-                    self.create_def(parent_def_id, impl_trait_node_id, DefPathData::ImplTrait);
+                    self.create_def(
+                        parent_def_id.def_id,
+                        impl_trait_node_id,
+                        DefPathData::ImplTrait,
+                    );
 
                     self.with_dyn_type_scope(false, |this| {
                         let node_id = this.next_node_id();
-                        let ty = this.lower_ty(
-                            &Ty {
-                                id: node_id,
-                                kind: TyKind::ImplTrait(impl_trait_node_id, bounds.clone()),
-                                span: this.lower_span(constraint.span),
-                                tokens: None,
-                            },
-                            itctx,
-                        );
+                        let ty = this.ast_arena.tys.alloc(Ty {
+                            id: node_id,
+                            kind: TyKind::ImplTrait(impl_trait_node_id, bounds.clone()),
+                            span: this.lower_span(constraint.span),
+                            tokens: None,
+                        });
+                        let ty = this.lower_ty(ty, itctx);
 
                         hir::TypeBindingKind::Equality { term: ty.into() }
                     })
@@ -1103,7 +1127,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_generic_arg(
         &mut self,
         arg: &ast::GenericArg,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::GenericArg<'hir> {
         match arg {
             ast::GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.lower_lifetime(&lt)),
@@ -1134,7 +1158,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 let node_id = self.next_node_id();
 
                                 // Add a definition for the in-band const def.
-                                self.create_def(parent_def_id, node_id, DefPathData::AnonConst);
+                                self.create_def(
+                                    parent_def_id.def_id,
+                                    node_id,
+                                    DefPathData::AnonConst,
+                                );
 
                                 let span = self.lower_span(ty.span);
                                 let path_expr = Expr {
@@ -1155,7 +1183,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }
                     _ => {}
                 }
-                GenericArg::Type(self.lower_ty_direct(&ty, itctx))
+                GenericArg::Type(self.lower_ty(&ty, itctx))
             }
             ast::GenericArg::Const(ct) => GenericArg::Const(ConstArg {
                 value: self.lower_anon_const(&ct),
@@ -1165,7 +1193,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     #[instrument(level = "debug", skip(self))]
-    fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> &'hir hir::Ty<'hir> {
+    fn lower_ty(&mut self, t: &Ty, itctx: &ImplTraitContext) -> &'hir hir::Ty<'hir> {
         self.arena.alloc(self.lower_ty_direct(t, itctx))
     }
 
@@ -1175,11 +1203,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         qself: &Option<QSelf>,
         path: &Path,
         param_mode: ParamMode,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::Ty<'hir> {
         // Check whether we should interpret this as a bare trait object.
         // This check mirrors the one in late resolution.  We only introduce this special case in
-        // the rare occurence we need to lower `Fresh` anonymous lifetimes.
+        // the rare occurrence we need to lower `Fresh` anonymous lifetimes.
         // The other cases when a qpath should be opportunistically made a trait object are handled
         // by `ty_path`.
         if qself.is_none()
@@ -1188,19 +1216,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             && let Res::Def(DefKind::Trait | DefKind::TraitAlias, _) = partial_res.base_res()
         {
             let (bounds, lifetime_bound) = self.with_dyn_type_scope(true, |this| {
+                let poly_trait_ref = this.ast_arena.ptr.alloc(PolyTraitRef {
+                    bound_generic_params: vec![],
+                    trait_ref: TraitRef { path: path.clone(), ref_id: t.id },
+                    span: t.span
+                });
                 let bound = this.lower_poly_trait_ref(
-                    &PolyTraitRef {
-                        bound_generic_params: vec![],
-                        trait_ref: TraitRef { path: path.clone(), ref_id: t.id },
-                        span: t.span
-                    },
+                    poly_trait_ref,
                     itctx,
                 );
                 let bounds = this.arena.alloc_from_iter([bound]);
                 let lifetime_bound = this.elided_dyn_bound(t.span);
                 (bounds, lifetime_bound)
             });
-            let kind = hir::TyKind::TraitObject(bounds, lifetime_bound, TraitObjectSyntax::None);
+            let kind = hir::TyKind::TraitObject(bounds, &lifetime_bound, TraitObjectSyntax::None);
             return hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.next_id() };
         }
 
@@ -1217,7 +1246,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.ty(span, hir::TyKind::Tup(tys))
     }
 
-    fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir> {
+    fn lower_ty_direct(&mut self, t: &Ty, itctx: &ImplTraitContext) -> hir::Ty<'hir> {
         let kind = match t.kind {
             TyKind::Infer => hir::TyKind::Infer,
             TyKind::Err => hir::TyKind::Err,
@@ -1245,7 +1274,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     generic_params,
                     unsafety: self.lower_unsafety(f.unsafety),
                     abi: self.lower_extern(f.ext),
-                    decl: self.lower_fn_decl(&f.decl, None, FnDeclKind::Pointer, None),
+                    decl: self.lower_fn_decl(&f.decl, None, t.span, FnDeclKind::Pointer, None),
                     param_names: self.lower_fn_params_to_names(&f.decl),
                 }))
             }
@@ -1260,14 +1289,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 return self.lower_path_ty(t, qself, path, ParamMode::Explicit, itctx);
             }
             TyKind::ImplicitSelf => {
+                let hir_id = self.next_id();
                 let res = self.expect_full_res(t.id);
                 let res = self.lower_res(res);
                 hir::TyKind::Path(hir::QPath::Resolved(
                     None,
                     self.arena.alloc(hir::Path {
                         res,
-                        segments: arena_vec![self; hir::PathSegment::from_ident(
-                            Ident::with_dummy_span(kw::SelfUpper)
+                        segments: arena_vec![self; hir::PathSegment::new(
+                            Ident::with_dummy_span(kw::SelfUpper),
+                            hir_id,
+                            res
                         )],
                         span: self.lower_span(t.span),
                     }),
@@ -1310,19 +1342,23 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             TyKind::ImplTrait(def_node_id, ref bounds) => {
                 let span = t.span;
                 match itctx {
-                    ImplTraitContext::ReturnPositionOpaqueTy { origin } => {
-                        self.lower_opaque_impl_trait(span, origin, def_node_id, bounds, itctx)
-                    }
-                    ImplTraitContext::TypeAliasesOpaqueTy => {
-                        let nested_itctx = ImplTraitContext::TypeAliasesOpaqueTy;
-                        self.lower_opaque_impl_trait(
+                    ImplTraitContext::ReturnPositionOpaqueTy { origin, in_trait } => self
+                        .lower_opaque_impl_trait(
                             span,
-                            hir::OpaqueTyOrigin::TyAlias,
+                            *origin,
                             def_node_id,
                             bounds,
-                            nested_itctx,
-                        )
-                    }
+                            *in_trait,
+                            itctx,
+                        ),
+                    ImplTraitContext::TypeAliasesOpaqueTy => self.lower_opaque_impl_trait(
+                        span,
+                        hir::OpaqueTyOrigin::TyAlias,
+                        def_node_id,
+                        bounds,
+                        false,
+                        &ImplTraitContext::TypeAliasesOpaqueTy,
+                    ),
                     ImplTraitContext::Universal => {
                         let span = t.span;
                         let ident = Ident::from_str_and_span(&pprust::ty_to_string(t), span);
@@ -1334,6 +1370,21 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         }
                         path
                     }
+                    ImplTraitContext::Disallowed(
+                        position @ (ImplTraitPosition::TraitReturn | ImplTraitPosition::ImplReturn),
+                    ) => {
+                        self.tcx
+                            .sess
+                            .create_feature_err(
+                                MisplacedImplTrait {
+                                    span: t.span,
+                                    position: DiagnosticArgFromDisplay(&position),
+                                },
+                                sym::return_position_impl_trait_in_trait,
+                            )
+                            .emit();
+                        hir::TyKind::Err
+                    }
                     ImplTraitContext::Disallowed(position) => {
                         self.tcx.sess.emit_err(MisplacedImplTrait {
                             span: t.span,
@@ -1385,14 +1436,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     /// added explicitly in the HIR). But this includes all the lifetimes, and we only want to
     /// capture the lifetimes that are referenced in the bounds. Therefore, we add *extra* lifetime parameters
     /// for the lifetimes that get captured (`'x`, in our example above) and reference those.
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     fn lower_opaque_impl_trait(
         &mut self,
         span: Span,
         origin: hir::OpaqueTyOrigin,
         opaque_ty_node_id: NodeId,
         bounds: &GenericBounds,
-        itctx: ImplTraitContext,
+        in_trait: bool,
+        itctx: &ImplTraitContext,
     ) -> hir::TyKind<'hir> {
         // Make sure we know that some funky desugaring has been going on here.
         // This is a first: there is code in other places like for loop
@@ -1480,6 +1532,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }),
                     bounds: hir_bounds,
                     origin,
+                    in_trait,
                 };
                 debug!(?opaque_ty_item);
 
@@ -1506,7 +1559,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         debug!(?lifetimes);
 
         // `impl Trait` now just becomes `Foo<'a, 'b, ..>`.
-        hir::TyKind::OpaqueDef(hir::ItemId { def_id: opaque_ty_def_id }, lifetimes)
+        hir::TyKind::OpaqueDef(
+            hir::ItemId { def_id: hir::OwnerId { def_id: opaque_ty_def_id } },
+            lifetimes,
+            in_trait,
+        )
     }
 
     /// Registers a new opaque type with the proper `NodeId`s and
@@ -1522,7 +1579,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // Generate an `type Foo = impl Trait;` declaration.
         trace!("registering opaque type with id {:#?}", opaque_ty_id);
         let opaque_ty_item = hir::Item {
-            def_id: opaque_ty_id,
+            def_id: hir::OwnerId { def_id: opaque_ty_id },
             ident: Ident::empty(),
             kind: opaque_ty_item_kind,
             vis_span: self.lower_span(span.shrink_to_lo()),
@@ -1565,8 +1622,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                 LifetimeRes::Fresh { param, binder: _ } => {
                     debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
-                    let old_def_id = self.local_def_id(param);
-                    if remapping.get(&old_def_id).is_none() {
+                    if let Some(old_def_id) = self.opt_local_def_id(param) && remapping.get(&old_def_id).is_none() {
                         let node_id = self.next_node_id();
 
                         let new_def_id = self.create_def(
@@ -1615,19 +1671,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     // `fn_def_id`: if `Some`, impl Trait arguments are lowered into generic parameters on the
     //      given DefId, otherwise impl Trait is disallowed. Must be `Some` if
     //      `make_ret_async` is also `Some`.
-    // `impl_trait_return_allow`: determines whether `impl Trait` can be used in return position.
-    //      This guards against trait declarations and implementations where `impl Trait` is
-    //      disallowed.
     // `make_ret_async`: if `Some`, converts `-> T` into `-> impl Future<Output = T>` in the
     //      return type. This is used for `async fn` declarations. The `NodeId` is the ID of the
-    //      return type `impl Trait` item.
-    #[tracing::instrument(level = "debug", skip(self))]
+    //      return type `impl Trait` item, and the `Span` points to the `async` keyword.
+    #[instrument(level = "debug", skip(self))]
     fn lower_fn_decl(
         &mut self,
         decl: &FnDecl,
         fn_node_id: Option<NodeId>,
+        fn_span: Span,
         kind: FnDeclKind,
-        make_ret_async: Option<NodeId>,
+        make_ret_async: Option<(NodeId, Span)>,
     ) -> &'hir hir::FnDecl<'hir> {
         let c_variadic = decl.c_variadic();
 
@@ -1640,11 +1694,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
         let inputs = self.arena.alloc_from_iter(inputs.iter().map(|param| {
             if fn_node_id.is_some() {
-                self.lower_ty_direct(&param.ty, ImplTraitContext::Universal)
+                self.lower_ty_direct(&param.ty, &ImplTraitContext::Universal)
             } else {
                 self.lower_ty_direct(
                     &param.ty,
-                    ImplTraitContext::Disallowed(match kind {
+                    &ImplTraitContext::Disallowed(match kind {
                         FnDeclKind::Fn | FnDeclKind::Inherent => {
                             unreachable!("fn should allow in-band lifetimes")
                         }
@@ -1658,20 +1712,39 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             }
         }));
 
-        let output = if let Some(ret_id) = make_ret_async {
+        let output = if let Some((ret_id, span)) = make_ret_async {
+            if !kind.async_fn_allowed(self.tcx) {
+                match kind {
+                    FnDeclKind::Trait | FnDeclKind::Impl => {
+                        self.tcx
+                            .sess
+                            .create_feature_err(
+                                TraitFnAsync { fn_span, span },
+                                sym::async_fn_in_trait,
+                            )
+                            .emit();
+                    }
+                    _ => {
+                        self.tcx.sess.emit_err(TraitFnAsync { fn_span, span });
+                    }
+                }
+            }
+
             self.lower_async_fn_ret_ty(
                 &decl.output,
                 fn_node_id.expect("`make_ret_async` but no `fn_def_id`"),
                 ret_id,
+                matches!(kind, FnDeclKind::Trait),
             )
         } else {
             match decl.output {
                 FnRetTy::Ty(ref ty) => {
-                    let context = match fn_node_id {
-                        Some(fn_node_id) if kind.impl_trait_return_allowed() => {
+                    let mut context = match fn_node_id {
+                        Some(fn_node_id) if kind.impl_trait_allowed(self.tcx) => {
                             let fn_def_id = self.local_def_id(fn_node_id);
                             ImplTraitContext::ReturnPositionOpaqueTy {
                                 origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
+                                in_trait: matches!(kind, FnDeclKind::Trait),
                             }
                         }
                         _ => ImplTraitContext::Disallowed(match kind {
@@ -1685,7 +1758,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             FnDeclKind::Impl => ImplTraitPosition::ImplReturn,
                         }),
                     };
-                    hir::FnRetTy::Return(self.lower_ty(ty, context))
+                    hir::FnRetTy::Return(self.lower_ty(ty, &mut context))
                 }
                 FnRetTy::Default(span) => hir::FnRetTy::DefaultReturn(self.lower_span(span)),
             }
@@ -1696,10 +1769,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             output,
             c_variadic,
             implicit_self: decl.inputs.get(0).map_or(hir::ImplicitSelfKind::None, |arg| {
-                use BindingMode::{ByRef, ByValue};
                 let is_mutable_pat = matches!(
                     arg.pat.kind,
-                    PatKind::Ident(ByValue(Mutability::Mut) | ByRef(Mutability::Mut), ..)
+                    PatKind::Ident(hir::BindingAnnotation(_, Mutability::Mut), ..)
                 );
 
                 match arg.ty.kind {
@@ -1730,12 +1802,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     // `output`: unlowered output type (`T` in `-> T`)
     // `fn_def_id`: `DefId` of the parent function (used to create child impl trait definition)
     // `opaque_ty_node_id`: `NodeId` of the opaque `impl Trait` type that should be created
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn lower_async_fn_ret_ty(
         &mut self,
         output: &FnRetTy,
         fn_node_id: NodeId,
         opaque_ty_node_id: NodeId,
+        in_trait: bool,
     ) -> hir::FnRetTy<'hir> {
         let span = output.span();
 
@@ -1862,8 +1935,18 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 //
                 // Then, we will create `fn foo(..) -> Foo<'_, '_>`, and
                 // hence the elision takes place at the fn site.
-                let future_bound =
-                    this.lower_async_fn_output_type_to_future_bound(output, fn_def_id, span);
+                let future_bound = this.lower_async_fn_output_type_to_future_bound(
+                    output,
+                    span,
+                    if in_trait && !this.tcx.features().return_position_impl_trait_in_trait {
+                        ImplTraitContext::Disallowed(ImplTraitPosition::TraitReturn)
+                    } else {
+                        ImplTraitContext::ReturnPositionOpaqueTy {
+                            origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
+                            in_trait,
+                        }
+                    },
+                );
 
                 let generic_params = this.arena.alloc_from_iter(collected_lifetimes.iter().map(
                     |&(new_node_id, lifetime, _)| {
@@ -1901,6 +1984,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }),
                     bounds: arena_vec![this; future_bound],
                     origin: hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
+                    in_trait,
                 };
 
                 trace!("exist ty from async fn def id: {:#?}", opaque_ty_def_id);
@@ -1937,8 +2021,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 let res = res.unwrap_or(
                     self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error),
                 );
-                let l = self.new_named_lifetime_with_res(id, span, ident, res);
-                hir::GenericArg::Lifetime(l)
+                hir::GenericArg::Lifetime(self.new_named_lifetime_with_res(id, span, ident, res))
             },
         ));
 
@@ -1946,8 +2029,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // Foo = impl Trait` is, internally, created as a child of the
         // async fn, so the *type parameters* are inherited.  It's
         // only the lifetime parameters that we must supply.
-        let opaque_ty_ref =
-            hir::TyKind::OpaqueDef(hir::ItemId { def_id: opaque_ty_def_id }, generic_args);
+        let opaque_ty_ref = hir::TyKind::OpaqueDef(
+            hir::ItemId { def_id: hir::OwnerId { def_id: opaque_ty_def_id } },
+            generic_args,
+            in_trait,
+        );
         let opaque_ty = self.ty(opaque_ty_span, opaque_ty_ref);
         hir::FnRetTy::Return(self.arena.alloc(opaque_ty))
     }
@@ -1956,8 +2042,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_async_fn_output_type_to_future_bound(
         &mut self,
         output: &FnRetTy,
-        fn_def_id: LocalDefId,
         span: Span,
+        mut nested_impl_trait_context: ImplTraitContext,
     ) -> hir::GenericBound<'hir> {
         // Compute the `T` in `Future<Output = T>` from the return type.
         let output_ty = match output {
@@ -1965,10 +2051,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 // Not `OpaqueTyOrigin::AsyncFn`: that's only used for the
                 // `impl Future` opaque type that `async fn` implicitly
                 // generates.
-                let context = ImplTraitContext::ReturnPositionOpaqueTy {
-                    origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
-                };
-                self.lower_ty(ty, context)
+                self.lower_ty(ty, &mut nested_impl_trait_context)
             }
             FnRetTy::Default(ret_ty_span) => self.arena.alloc(self.ty_tup(*ret_ty_span, &[])),
         };
@@ -1994,7 +2077,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_param_bound(
         &mut self,
         tpb: &GenericBound,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::GenericBound<'hir> {
         match tpb {
             GenericBound::Trait(p, modifier) => hir::GenericBound::Trait(
@@ -2007,24 +2090,24 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime {
+    fn lower_lifetime(&mut self, l: &Lifetime) -> &'hir hir::Lifetime {
         let span = self.lower_span(l.ident.span);
         let ident = self.lower_ident(l.ident);
         self.new_named_lifetime(l.id, l.id, span, ident)
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn new_named_lifetime_with_res(
         &mut self,
         id: NodeId,
         span: Span,
         ident: Ident,
         res: LifetimeRes,
-    ) -> hir::Lifetime {
+    ) -> &'hir hir::Lifetime {
         let name = match res {
             LifetimeRes::Param { param, .. } => {
                 let p_name = ParamName::Plain(ident);
-                let param = self.resolver.get_remapped_def_id(param);
+                let param = self.get_remapped_def_id(param);
 
                 hir::LifetimeName::Param(param, p_name)
             }
@@ -2041,17 +2124,21 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         };
 
         debug!(?name);
-        hir::Lifetime { hir_id: self.lower_node_id(id), span: self.lower_span(span), name }
+        self.arena.alloc(hir::Lifetime {
+            hir_id: self.lower_node_id(id),
+            span: self.lower_span(span),
+            name,
+        })
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn new_named_lifetime(
         &mut self,
         id: NodeId,
         new_id: NodeId,
         span: Span,
         ident: Ident,
-    ) -> hir::Lifetime {
+    ) -> &'hir hir::Lifetime {
         let res = self.resolver.get_lifetime_res(id).unwrap_or(LifetimeRes::Error);
         self.new_named_lifetime_with_res(new_id, span, ident, res)
     }
@@ -2106,7 +2193,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             GenericParamKind::Type { ref default, .. } => {
                 let kind = hir::GenericParamKind::Type {
                     default: default.as_ref().map(|x| {
-                        self.lower_ty(x, ImplTraitContext::Disallowed(ImplTraitPosition::Type))
+                        self.lower_ty(x, &ImplTraitContext::Disallowed(ImplTraitPosition::Type))
                     }),
                     synthetic: false,
                 };
@@ -2114,7 +2201,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 (hir::ParamName::Plain(self.lower_ident(param.ident)), kind)
             }
             GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
-                let ty = self.lower_ty(&ty, ImplTraitContext::Disallowed(ImplTraitPosition::Type));
+                let ty = self.lower_ty(&ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Type));
                 let default = default.as_ref().map(|def| self.lower_anon_const(def));
                 (
                     hir::ParamName::Plain(self.lower_ident(param.ident)),
@@ -2124,7 +2211,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext) -> hir::TraitRef<'hir> {
+    fn lower_trait_ref(&mut self, p: &TraitRef, itctx: &ImplTraitContext) -> hir::TraitRef<'hir> {
         let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) {
             hir::QPath::Resolved(None, path) => path,
             qpath => panic!("lower_trait_ref: unexpected QPath `{:?}`", qpath),
@@ -2132,11 +2219,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         hir::TraitRef { path, hir_ref_id: self.lower_node_id(p.ref_id) }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn lower_poly_trait_ref(
         &mut self,
         p: &PolyTraitRef,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::PolyTraitRef<'hir> {
         let bound_generic_params =
             self.lower_lifetime_binder(p.trait_ref.ref_id, &p.bound_generic_params);
@@ -2144,14 +2231,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         hir::PolyTraitRef { bound_generic_params, trait_ref, span: self.lower_span(p.span) }
     }
 
-    fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext) -> hir::MutTy<'hir> {
+    fn lower_mt(&mut self, mt: &MutTy, itctx: &ImplTraitContext) -> hir::MutTy<'hir> {
         hir::MutTy { ty: self.lower_ty(&mt.ty, itctx), mutbl: mt.mutbl }
     }
 
+    #[instrument(level = "debug", skip(self), ret)]
     fn lower_param_bounds(
         &mut self,
         bounds: &[GenericBound],
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::GenericBounds<'hir> {
         self.arena.alloc_from_iter(self.lower_param_bounds_mut(bounds, itctx))
     }
@@ -2159,11 +2247,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_param_bounds_mut<'s>(
         &'s mut self,
         bounds: &'s [GenericBound],
-        itctx: ImplTraitContext,
+        itctx: &'s ImplTraitContext,
     ) -> impl Iterator<Item = hir::GenericBound<'hir>> + Captures<'s> + Captures<'a> {
         bounds.iter().map(move |bound| self.lower_param_bound(bound, itctx))
     }
 
+    #[instrument(level = "debug", skip(self), ret)]
     fn lower_generic_and_bounds(
         &mut self,
         node_id: NodeId,
@@ -2189,16 +2278,19 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             node_id,
             &GenericParamKind::Type { default: None },
             bounds,
-            ImplTraitContext::Universal,
+            &ImplTraitContext::Universal,
             hir::PredicateOrigin::ImplTrait,
         );
 
+        let hir_id = self.next_id();
+        let res = Res::Def(DefKind::TyParam, def_id.to_def_id());
         let ty = hir::TyKind::Path(hir::QPath::Resolved(
             None,
             self.arena.alloc(hir::Path {
                 span: self.lower_span(span),
-                res: Res::Def(DefKind::TyParam, def_id.to_def_id()),
-                segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident))],
+                res,
+                segments:
+                    arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
             }),
         ));
 
@@ -2361,11 +2453,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     fn pat_ident(&mut self, span: Span, ident: Ident) -> (&'hir hir::Pat<'hir>, hir::HirId) {
-        self.pat_ident_binding_mode(span, ident, hir::BindingAnnotation::Unannotated)
+        self.pat_ident_binding_mode(span, ident, hir::BindingAnnotation::NONE)
     }
 
     fn pat_ident_mut(&mut self, span: Span, ident: Ident) -> (hir::Pat<'hir>, hir::HirId) {
-        self.pat_ident_binding_mode_mut(span, ident, hir::BindingAnnotation::Unannotated)
+        self.pat_ident_binding_mode_mut(span, ident, hir::BindingAnnotation::NONE)
     }
 
     fn pat_ident_binding_mode(
@@ -2454,14 +2546,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     /// bound, like the bound in `Box<dyn Debug>`. This method is not invoked
     /// when the bound is written, even if it is written with `'_` like in
     /// `Box<dyn Debug + '_>`. In those cases, `lower_lifetime` is invoked.
-    fn elided_dyn_bound(&mut self, span: Span) -> hir::Lifetime {
+    fn elided_dyn_bound(&mut self, span: Span) -> &'hir hir::Lifetime {
         let r = hir::Lifetime {
             hir_id: self.next_id(),
             span: self.lower_span(span),
             name: hir::LifetimeName::ImplicitObjectLifetimeDefault,
         };
         debug!("elided_dyn_bound: r={:?}", r);
-        r
+        self.arena.alloc(r)
     }
 }
 
diff --git a/compiler/rustc_ast_lowering/src/lifetime_collector.rs b/compiler/rustc_ast_lowering/src/lifetime_collector.rs
index 8c67cebae55a..914fc5f58da1 100644
--- a/compiler/rustc_ast_lowering/src/lifetime_collector.rs
+++ b/compiler/rustc_ast_lowering/src/lifetime_collector.rs
@@ -63,9 +63,9 @@ impl<'ast> Visitor<'ast> for LifetimeCollectVisitor<'ast> {
         self.record_lifetime_use(*lifetime);
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
-        self.record_elided_anchor(path_segment.id, path_span);
-        visit::walk_path_segment(self, path_span, path_segment);
+    fn visit_path_segment(&mut self, path_segment: &'ast PathSegment) {
+        self.record_elided_anchor(path_segment.id, path_segment.ident.span);
+        visit::walk_path_segment(self, path_segment);
     }
 
     fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef) {
diff --git a/compiler/rustc_ast_lowering/src/pat.rs b/compiler/rustc_ast_lowering/src/pat.rs
index 1efa19a3a828..1ea76fdbfcbb 100644
--- a/compiler/rustc_ast_lowering/src/pat.rs
+++ b/compiler/rustc_ast_lowering/src/pat.rs
@@ -24,7 +24,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             let node = loop {
                 match pattern.kind {
                     PatKind::Wild => break hir::PatKind::Wild,
-                    PatKind::Ident(ref binding_mode, ident, ref sub) => {
+                    PatKind::Ident(binding_mode, ident, ref sub) => {
                         let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
                         break self.lower_pat_ident(pattern, binding_mode, ident, lower_sub);
                     }
@@ -37,7 +37,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             qself,
                             path,
                             ParamMode::Optional,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                            &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         );
                         let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
                         break hir::PatKind::TupleStruct(qpath, pats, ddpos);
@@ -53,7 +53,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             qself,
                             path,
                             ParamMode::Optional,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                            &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         );
                         break hir::PatKind::Path(qpath);
                     }
@@ -63,7 +63,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             qself,
                             path,
                             ParamMode::Optional,
-                            ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                            &mut ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                         );
 
                         let fs = self.arena.alloc_from_iter(fields.iter().map(|f| {
@@ -116,7 +116,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         &mut self,
         pats: &[P<Pat>],
         ctx: &str,
-    ) -> (&'hir [hir::Pat<'hir>], Option<usize>) {
+    ) -> (&'hir [hir::Pat<'hir>], hir::DotDotPos) {
         let mut elems = Vec::with_capacity(pats.len());
         let mut rest = None;
 
@@ -160,7 +160,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             }
         }
 
-        (self.arena.alloc_from_iter(elems), rest.map(|(ddpos, _)| ddpos))
+        (self.arena.alloc_from_iter(elems), hir::DotDotPos::new(rest.map(|(ddpos, _)| ddpos)))
     }
 
     /// Lower a slice pattern of form `[pat_0, ..., pat_n]` into
@@ -176,9 +176,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let mut prev_rest_span = None;
 
         // Lowers `$bm $ident @ ..` to `$bm $ident @ _`.
-        let lower_rest_sub = |this: &mut Self, pat, bm, ident, sub| {
+        let lower_rest_sub = |this: &mut Self, pat, ann, ident, sub| {
             let lower_sub = |this: &mut Self| Some(this.pat_wild_with_node_id_of(sub));
-            let node = this.lower_pat_ident(pat, bm, ident, lower_sub);
+            let node = this.lower_pat_ident(pat, ann, ident, lower_sub);
             this.pat_with_node_id_of(pat, node)
         };
 
@@ -194,9 +194,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 }
                 // Found a sub-slice pattern `$binding_mode $ident @ ..`.
                 // Record, lower it to `$binding_mode $ident @ _`, and stop here.
-                PatKind::Ident(ref bm, ident, Some(ref sub)) if sub.is_rest() => {
+                PatKind::Ident(ann, ident, Some(ref sub)) if sub.is_rest() => {
                     prev_rest_span = Some(sub.span);
-                    slice = Some(self.arena.alloc(lower_rest_sub(self, pat, bm, ident, sub)));
+                    slice = Some(self.arena.alloc(lower_rest_sub(self, pat, ann, ident, sub)));
                     break;
                 }
                 // It was not a subslice pattern so lower it normally.
@@ -209,9 +209,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             // There was a previous subslice pattern; make sure we don't allow more.
             let rest_span = match pat.kind {
                 PatKind::Rest => Some(pat.span),
-                PatKind::Ident(ref bm, ident, Some(ref sub)) if sub.is_rest() => {
+                PatKind::Ident(ann, ident, Some(ref sub)) if sub.is_rest() => {
                     // #69103: Lower into `binding @ _` as above to avoid ICEs.
-                    after.push(lower_rest_sub(self, pat, bm, ident, sub));
+                    after.push(lower_rest_sub(self, pat, ann, ident, sub));
                     Some(sub.span)
                 }
                 _ => None,
@@ -235,7 +235,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_pat_ident(
         &mut self,
         p: &Pat,
-        binding_mode: &BindingMode,
+        annotation: BindingAnnotation,
         ident: Ident,
         lower_sub: impl FnOnce(&mut Self) -> Option<&'hir hir::Pat<'hir>>,
     ) -> hir::PatKind<'hir> {
@@ -248,29 +248,24 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 };
 
                 hir::PatKind::Binding(
-                    self.lower_binding_mode(binding_mode),
+                    annotation,
                     self.lower_node_id(canonical_id),
                     self.lower_ident(ident),
                     lower_sub(self),
                 )
             }
-            Some(res) => hir::PatKind::Path(hir::QPath::Resolved(
-                None,
-                self.arena.alloc(hir::Path {
-                    span: self.lower_span(ident.span),
-                    res: self.lower_res(res),
-                    segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident))],
-                }),
-            )),
-        }
-    }
-
-    fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation {
-        match *b {
-            BindingMode::ByValue(Mutability::Not) => hir::BindingAnnotation::Unannotated,
-            BindingMode::ByRef(Mutability::Not) => hir::BindingAnnotation::Ref,
-            BindingMode::ByValue(Mutability::Mut) => hir::BindingAnnotation::Mutable,
-            BindingMode::ByRef(Mutability::Mut) => hir::BindingAnnotation::RefMut,
+            Some(res) => {
+                let hir_id = self.next_id();
+                let res = self.lower_res(res);
+                hir::PatKind::Path(hir::QPath::Resolved(
+                    None,
+                    self.arena.alloc(hir::Path {
+                        span: self.lower_span(ident.span),
+                        res,
+                        segments: arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
+                    }),
+            ))
+            }
         }
     }
 
diff --git a/compiler/rustc_ast_lowering/src/path.rs b/compiler/rustc_ast_lowering/src/path.rs
index 5874d08a94fe..6bb1bb9eace8 100644
--- a/compiler/rustc_ast_lowering/src/path.rs
+++ b/compiler/rustc_ast_lowering/src/path.rs
@@ -13,7 +13,6 @@ use rustc_span::symbol::{kw, Ident};
 use rustc_span::{BytePos, Span, DUMMY_SP};
 
 use smallvec::smallvec;
-use tracing::debug;
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
     #[instrument(level = "trace", skip(self))]
@@ -23,7 +22,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         qself: &Option<QSelf>,
         p: &Path,
         param_mode: ParamMode,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::QPath<'hir> {
         let qself_position = qself.as_ref().map(|q| q.position);
         let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx));
@@ -157,7 +156,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     segment,
                     param_mode,
                     ParenthesizedGenericArgs::Err,
-                    ImplTraitContext::Disallowed(ImplTraitPosition::Path),
+                    &ImplTraitContext::Disallowed(ImplTraitPosition::Path),
                 )
             })),
             span: self.lower_span(p.span),
@@ -181,7 +180,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         segment: &PathSegment,
         param_mode: ParamMode,
         parenthesized_generic_args: ParenthesizedGenericArgs,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> hir::PathSegment<'hir> {
         debug!("path_span: {:?}, lower_path_segment(segment: {:?})", path_span, segment,);
         let (mut generic_args, infer_args) = if let Some(ref generic_args) = segment.args {
@@ -251,16 +250,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
 
         let res = self.expect_full_res(segment.id);
-        let id = self.lower_node_id(segment.id);
+        let hir_id = self.lower_node_id(segment.id);
         debug!(
             "lower_path_segment: ident={:?} original-id={:?} new-id={:?}",
-            segment.ident, segment.id, id,
+            segment.ident, segment.id, hir_id,
         );
 
         hir::PathSegment {
             ident: self.lower_ident(segment.ident),
-            hir_id: Some(id),
-            res: Some(self.lower_res(res)),
+            hir_id,
+            res: self.lower_res(res),
             infer_args,
             args: if generic_args.is_empty() && generic_args.span.is_empty() {
                 None
@@ -317,7 +316,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         &mut self,
         data: &AngleBracketedArgs,
         param_mode: ParamMode,
-        itctx: ImplTraitContext,
+        itctx: &ImplTraitContext,
     ) -> (GenericArgsCtor<'hir>, bool) {
         let has_non_lt_args = data.args.iter().any(|arg| match arg {
             AngleBracketedArg::Arg(ast::GenericArg::Lifetime(_))
@@ -351,15 +350,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // we generally don't permit such things (see #51008).
         let ParenthesizedArgs { span, inputs, inputs_span, output } = data;
         let inputs = self.arena.alloc_from_iter(inputs.iter().map(|ty| {
-            self.lower_ty_direct(ty, ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitParam))
+            self.lower_ty_direct(ty, &ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitParam))
         }));
         let output_ty = match output {
             FnRetTy::Ty(ty) => {
-                self.lower_ty(&ty, ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitReturn))
+                self.lower_ty(&ty, &ImplTraitContext::Disallowed(ImplTraitPosition::FnTraitReturn))
             }
             FnRetTy::Default(_) => self.arena.alloc(self.ty_tup(*span, &[])),
         };
-        let args = smallvec![GenericArg::Type(self.ty_tup(*inputs_span, inputs))];
+        let args = smallvec![GenericArg::Type(self.arena.alloc(self.ty_tup(*inputs_span, inputs)))];
         let binding = self.output_ty_binding(output_ty.span, output_ty);
         (
             GenericArgsCtor {
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index c36c4ad54da4..ecf74c760202 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -223,11 +223,9 @@ impl<'a> AstValidator<'a> {
                 for (i, segment) in path.segments.iter().enumerate() {
                     // Allow `impl Trait` iff we're on the final path segment
                     if i == path.segments.len() - 1 {
-                        self.visit_path_segment(path.span, segment);
+                        self.visit_path_segment(segment);
                     } else {
-                        self.with_banned_impl_trait(|this| {
-                            this.visit_path_segment(path.span, segment)
-                        });
+                        self.with_banned_impl_trait(|this| this.visit_path_segment(segment));
                     }
                 }
             }
@@ -281,8 +279,8 @@ impl<'a> AstValidator<'a> {
     fn check_decl_no_pat(decl: &FnDecl, mut report_err: impl FnMut(Span, Option<Ident>, bool)) {
         for Param { pat, .. } in &decl.inputs {
             match pat.kind {
-                PatKind::Ident(BindingMode::ByValue(Mutability::Not), _, None) | PatKind::Wild => {}
-                PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ident, None) => {
+                PatKind::Ident(BindingAnnotation::NONE, _, None) | PatKind::Wild => {}
+                PatKind::Ident(BindingAnnotation::MUT, ident, None) => {
                     report_err(pat.span, Some(ident), true)
                 }
                 _ => report_err(pat.span, None, false),
@@ -290,12 +288,6 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn check_trait_fn_not_async(&self, fn_span: Span, asyncness: Async) {
-        if let Async::Yes { span, .. } = asyncness {
-            self.session.emit_err(TraitFnAsync { fn_span, span });
-        }
-    }
-
     fn check_trait_fn_not_const(&self, constness: Const) {
         if let Const::Yes(span) = constness {
             self.session.emit_err(TraitFnConst { span });
@@ -845,10 +837,10 @@ fn validate_generic_param_order(
         let (kind, bounds, span) = (&param.kind, &param.bounds, ident.span);
         let (ord_kind, ident) = match &param.kind {
             GenericParamKind::Lifetime => (ParamKindOrd::Lifetime, ident.to_string()),
-            GenericParamKind::Type { default: _ } => (ParamKindOrd::Type, ident.to_string()),
+            GenericParamKind::Type { default: _ } => (ParamKindOrd::TypeOrConst, ident.to_string()),
             GenericParamKind::Const { ref ty, kw_span: _, default: _ } => {
                 let ty = pprust::ty_to_string(ty);
-                (ParamKindOrd::Const, format!("const {}: {}", ident, ty))
+                (ParamKindOrd::TypeOrConst, format!("const {}: {}", ident, ty))
             }
         };
         param_idents.push((kind, ord_kind, bounds, idx, ident));
@@ -1299,7 +1291,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
     }
 
     // Mirrors `visit::walk_generic_args`, but tracks relevant state.
-    fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
+    fn visit_generic_args(&mut self, generic_args: &'a GenericArgs) {
         match *generic_args {
             GenericArgs::AngleBracketed(ref data) => {
                 self.check_generic_args_before_constraints(data);
@@ -1423,7 +1415,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     if !self.is_tilde_const_allowed {
                         self.err_handler()
                             .struct_span_err(bound.span(), "`~const` is not allowed here")
-                            .note("only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions")
+                            .note("only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions")
                             .emit();
                     }
                 }
@@ -1531,11 +1523,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             });
         }
 
-        let tilde_const_allowed =
-            matches!(fk.header(), Some(FnHeader { constness: Const::Yes(_), .. }))
-                || matches!(fk.ctxt(), Some(FnCtxt::Assoc(_)));
+        let tilde_const_allowed = matches!(fk.header(), Some(FnHeader { .. }))
+            || matches!(fk.ctxt(), Some(FnCtxt::Assoc(_)));
 
-        self.with_tilde_const(tilde_const_allowed, |this| visit::walk_fn(this, fk, span));
+        self.with_tilde_const(tilde_const_allowed, |this| visit::walk_fn(this, fk));
     }
 
     fn visit_assoc_item(&mut self, item: &'a AssocItem, ctxt: AssocCtxt) {
@@ -1596,7 +1587,6 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             self.invalid_visibility(&item.vis, None);
             if let AssocItemKind::Fn(box Fn { sig, .. }) = &item.kind {
                 self.check_trait_fn_not_const(sig.header.constness);
-                self.check_trait_fn_not_async(item.span, sig.header.asyncness);
             }
         }
 
@@ -1800,7 +1790,7 @@ pub(crate) enum ForbiddenLetReason {
     NotSupportedOr(Span),
     /// A let chain with invalid parentheses
     ///
-    /// For exemple, `let 1 = 1 && (expr && expr)` is allowed
+    /// For example, `let 1 = 1 && (expr && expr)` is allowed
     /// but `(let 1 = 1 && (let 1 = 1 && (let 1 = 1))) && let a = 1` is not
     NotSupportedParentheses(Span),
 }
diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index 21467e576519..035f0ce1cbc4 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -1,12 +1,12 @@
 //! Errors emitted by ast_passes.
 
-use rustc_errors::{fluent, AddSubdiagnostic, Applicability, Diagnostic};
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
+use rustc_errors::{fluent, AddToDiagnostic, Applicability, Diagnostic};
+use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
 use crate::ast_validation::ForbiddenLetReason;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_let)]
 #[note]
 pub struct ForbiddenLet {
@@ -16,7 +16,7 @@ pub struct ForbiddenLet {
     pub(crate) reason: ForbiddenLetReason,
 }
 
-impl AddSubdiagnostic for ForbiddenLetReason {
+impl AddToDiagnostic for ForbiddenLetReason {
     fn add_to_diagnostic(self, diag: &mut Diagnostic) {
         match self {
             Self::GenericForbidden => {}
@@ -30,7 +30,7 @@ impl AddSubdiagnostic for ForbiddenLetReason {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_let_stable)]
 #[note]
 pub struct ForbiddenLetStable {
@@ -38,21 +38,21 @@ pub struct ForbiddenLetStable {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_assoc_constraint)]
 pub struct ForbiddenAssocConstraint {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::keyword_lifetime)]
 pub struct KeywordLifetime {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::invalid_label)]
 pub struct InvalidLabel {
     #[primary_span]
@@ -60,7 +60,7 @@ pub struct InvalidLabel {
     pub name: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::invalid_visibility, code = "E0449")]
 pub struct InvalidVisibility {
     #[primary_span]
@@ -71,7 +71,7 @@ pub struct InvalidVisibility {
     pub note: Option<InvalidVisibilityNote>,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum InvalidVisibilityNote {
     #[note(ast_passes::individual_impl_items)]
     IndividualImplItems,
@@ -79,18 +79,7 @@ pub enum InvalidVisibilityNote {
     IndividualForeignItems,
 }
 
-#[derive(SessionDiagnostic)]
-#[diag(ast_passes::trait_fn_async, code = "E0706")]
-#[note]
-#[note(ast_passes::note2)]
-pub struct TraitFnAsync {
-    #[primary_span]
-    pub fn_span: Span,
-    #[label]
-    pub span: Span,
-}
-
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::trait_fn_const, code = "E0379")]
 pub struct TraitFnConst {
     #[primary_span]
@@ -98,21 +87,21 @@ pub struct TraitFnConst {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_lifetime_bound)]
 pub struct ForbiddenLifetimeBound {
     #[primary_span]
     pub spans: Vec<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_non_lifetime_param)]
 pub struct ForbiddenNonLifetimeParam {
     #[primary_span]
     pub spans: Vec<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_param_too_many)]
 pub struct FnParamTooMany {
     #[primary_span]
@@ -120,21 +109,21 @@ pub struct FnParamTooMany {
     pub max_num_args: usize,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_param_c_var_args_only)]
 pub struct FnParamCVarArgsOnly {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_param_c_var_args_not_last)]
 pub struct FnParamCVarArgsNotLast {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_param_doc_comment)]
 pub struct FnParamDocComment {
     #[primary_span]
@@ -142,14 +131,14 @@ pub struct FnParamDocComment {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_param_forbidden_attr)]
 pub struct FnParamForbiddenAttr {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_param_forbidden_self)]
 #[note]
 pub struct FnParamForbiddenSelf {
@@ -158,7 +147,7 @@ pub struct FnParamForbiddenSelf {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_default)]
 pub struct ForbiddenDefault {
     #[primary_span]
@@ -167,7 +156,7 @@ pub struct ForbiddenDefault {
     pub def_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::assoc_const_without_body)]
 pub struct AssocConstWithoutBody {
     #[primary_span]
@@ -176,7 +165,7 @@ pub struct AssocConstWithoutBody {
     pub replace_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::assoc_fn_without_body)]
 pub struct AssocFnWithoutBody {
     #[primary_span]
@@ -185,7 +174,7 @@ pub struct AssocFnWithoutBody {
     pub replace_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::assoc_type_without_body)]
 pub struct AssocTypeWithoutBody {
     #[primary_span]
@@ -194,7 +183,7 @@ pub struct AssocTypeWithoutBody {
     pub replace_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::const_without_body)]
 pub struct ConstWithoutBody {
     #[primary_span]
@@ -203,7 +192,7 @@ pub struct ConstWithoutBody {
     pub replace_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::static_without_body)]
 pub struct StaticWithoutBody {
     #[primary_span]
@@ -212,7 +201,7 @@ pub struct StaticWithoutBody {
     pub replace_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::ty_alias_without_body)]
 pub struct TyAliasWithoutBody {
     #[primary_span]
@@ -221,7 +210,7 @@ pub struct TyAliasWithoutBody {
     pub replace_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ast_passes::fn_without_body)]
 pub struct FnWithoutBody {
     #[primary_span]
@@ -238,7 +227,7 @@ pub struct ExternBlockSuggestion {
     pub abi: Option<Symbol>,
 }
 
-impl AddSubdiagnostic for ExternBlockSuggestion {
+impl AddToDiagnostic for ExternBlockSuggestion {
     fn add_to_diagnostic(self, diag: &mut Diagnostic) {
         let start_suggestion = if let Some(abi) = self.abi {
             format!("extern \"{}\" {{", abi)
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 6f7e88eb86f1..0017a28cf1b1 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -3,15 +3,13 @@ use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
 use rustc_ast::{AssocConstraint, AssocConstraintKind, NodeId};
 use rustc_ast::{PatKind, RangeEnd, VariantData};
 use rustc_errors::{struct_span_err, Applicability, StashKey};
-use rustc_feature::Features;
-use rustc_feature::{AttributeGate, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
-use rustc_session::parse::{feature_err, feature_warn};
+use rustc_feature::{AttributeGate, BuiltinAttribute, Features, GateIssue, BUILTIN_ATTRIBUTE_MAP};
+use rustc_session::parse::{feature_err, feature_err_issue, feature_warn};
 use rustc_session::Session;
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
-
-use tracing::debug;
+use rustc_target::spec::abi;
 
 macro_rules! gate_feature_fn {
     ($visitor: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr, $help: expr) => {{
@@ -86,210 +84,26 @@ impl<'a> PostExpansionVisitor<'a> {
             }
         }
 
-        match symbol_unescaped.as_str() {
-            // Stable
-            "Rust" | "C" | "cdecl" | "stdcall" | "fastcall" | "aapcs" | "win64" | "sysv64"
-            | "system" => {}
-            "rust-intrinsic" => {
-                gate_feature_post!(&self, intrinsics, span, "intrinsics are subject to change");
-            }
-            "platform-intrinsic" => {
-                gate_feature_post!(
-                    &self,
-                    platform_intrinsics,
+        match abi::is_enabled(&self.features, span, symbol_unescaped.as_str()) {
+            Ok(()) => (),
+            Err(abi::AbiDisabled::Unstable { feature, explain }) => {
+                feature_err_issue(
+                    &self.sess.parse_sess,
+                    feature,
                     span,
-                    "platform intrinsics are experimental and possibly buggy"
-                );
+                    GateIssue::Language,
+                    explain,
+                )
+                .emit();
             }
-            "vectorcall" => {
-                gate_feature_post!(
-                    &self,
-                    abi_vectorcall,
-                    span,
-                    "vectorcall is experimental and subject to change"
-                );
-            }
-            "thiscall" => {
-                gate_feature_post!(
-                    &self,
-                    abi_thiscall,
-                    span,
-                    "thiscall is experimental and subject to change"
-                );
-            }
-            "rust-call" => {
-                gate_feature_post!(
-                    &self,
-                    unboxed_closures,
-                    span,
-                    "rust-call ABI is subject to change"
-                );
-            }
-            "rust-cold" => {
-                gate_feature_post!(
-                    &self,
-                    rust_cold_cc,
-                    span,
-                    "rust-cold is experimental and subject to change"
-                );
-            }
-            "ptx-kernel" => {
-                gate_feature_post!(
-                    &self,
-                    abi_ptx,
-                    span,
-                    "PTX ABIs are experimental and subject to change"
-                );
-            }
-            "unadjusted" => {
-                gate_feature_post!(
-                    &self,
-                    abi_unadjusted,
-                    span,
-                    "unadjusted ABI is an implementation detail and perma-unstable"
-                );
-            }
-            "msp430-interrupt" => {
-                gate_feature_post!(
-                    &self,
-                    abi_msp430_interrupt,
-                    span,
-                    "msp430-interrupt ABI is experimental and subject to change"
-                );
-            }
-            "x86-interrupt" => {
-                gate_feature_post!(
-                    &self,
-                    abi_x86_interrupt,
-                    span,
-                    "x86-interrupt ABI is experimental and subject to change"
-                );
-            }
-            "amdgpu-kernel" => {
-                gate_feature_post!(
-                    &self,
-                    abi_amdgpu_kernel,
-                    span,
-                    "amdgpu-kernel ABI is experimental and subject to change"
-                );
-            }
-            "avr-interrupt" | "avr-non-blocking-interrupt" => {
-                gate_feature_post!(
-                    &self,
-                    abi_avr_interrupt,
-                    span,
-                    "avr-interrupt and avr-non-blocking-interrupt ABIs are experimental and subject to change"
-                );
-            }
-            "efiapi" => {
-                gate_feature_post!(
-                    &self,
-                    abi_efiapi,
-                    span,
-                    "efiapi ABI is experimental and subject to change"
-                );
-            }
-            "C-cmse-nonsecure-call" => {
-                gate_feature_post!(
-                    &self,
-                    abi_c_cmse_nonsecure_call,
-                    span,
-                    "C-cmse-nonsecure-call ABI is experimental and subject to change"
-                );
-            }
-            "C-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "C-unwind ABI is experimental and subject to change"
-                );
-            }
-            "stdcall-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "stdcall-unwind ABI is experimental and subject to change"
-                );
-            }
-            "system-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "system-unwind ABI is experimental and subject to change"
-                );
-            }
-            "thiscall-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "thiscall-unwind ABI is experimental and subject to change"
-                );
-            }
-            "cdecl-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "cdecl-unwind ABI is experimental and subject to change"
-                );
-            }
-            "fastcall-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "fastcall-unwind ABI is experimental and subject to change"
-                );
-            }
-            "vectorcall-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "vectorcall-unwind ABI is experimental and subject to change"
-                );
-            }
-            "aapcs-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "aapcs-unwind ABI is experimental and subject to change"
-                );
-            }
-            "win64-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "win64-unwind ABI is experimental and subject to change"
-                );
-            }
-            "sysv64-unwind" => {
-                gate_feature_post!(
-                    &self,
-                    c_unwind,
-                    span,
-                    "sysv64-unwind ABI is experimental and subject to change"
-                );
-            }
-            "wasm" => {
-                gate_feature_post!(
-                    &self,
-                    wasm_abi,
-                    span,
-                    "wasm ABI is experimental and subject to change"
-                );
-            }
-            abi => {
+            Err(abi::AbiDisabled::Unrecognized) => {
                 if self.sess.opts.pretty.map_or(true, |ppm| ppm.needs_hir()) {
                     self.sess.parse_sess.span_diagnostic.delay_span_bug(
                         span,
-                        &format!("unrecognized ABI not caught in lowering: {}", abi),
+                        &format!(
+                            "unrecognized ABI not caught in lowering: {}",
+                            symbol_unescaped.as_str()
+                        ),
                     );
                 }
             }
@@ -342,25 +156,6 @@ impl<'a> PostExpansionVisitor<'a> {
         }
     }
 
-    fn check_gat(&self, generics: &ast::Generics, span: Span) {
-        if !generics.params.is_empty() {
-            gate_feature_post!(
-                &self,
-                generic_associated_types,
-                span,
-                "generic associated types are unstable"
-            );
-        }
-        if !generics.where_clause.predicates.is_empty() {
-            gate_feature_post!(
-                &self,
-                generic_associated_types,
-                span,
-                "where clauses on associated types are unstable"
-            );
-        }
-    }
-
     /// Feature gate `impl Trait` inside `type Alias = $type_expr;`.
     fn check_impl_trait(&self, ty: &ast::Ty) {
         struct ImplTraitVisitor<'a> {
@@ -575,6 +370,9 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             ast::TyKind::Never => {
                 gate_feature_post!(&self, never_type, ty.span, "the `!` type is experimental");
             }
+            ast::TyKind::TraitObject(_, ast::TraitObjectSyntax::DynStar, ..) => {
+                gate_feature_post!(&self, dyn_star, ty.span, "dyn* trait objects are unstable");
+            }
             _ => {}
         }
         visit::walk_ty(self, ty)
@@ -701,7 +499,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             gate_feature_post!(&self, c_variadic, span, "C-variadic functions are unstable");
         }
 
-        visit::walk_fn(self, fn_kind, span)
+        visit::walk_fn(self, fn_kind)
     }
 
     fn visit_assoc_constraint(&mut self, constraint: &'a AssocConstraint) {
@@ -719,7 +517,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_assoc_item(&mut self, i: &'a ast::AssocItem, ctxt: AssocCtxt) {
         let is_fn = match i.kind {
             ast::AssocItemKind::Fn(_) => true,
-            ast::AssocItemKind::TyAlias(box ast::TyAlias { ref generics, ref ty, .. }) => {
+            ast::AssocItemKind::TyAlias(box ast::TyAlias { ref ty, .. }) => {
                 if let (Some(_), AssocCtxt::Trait) = (ty, ctxt) {
                     gate_feature_post!(
                         &self,
@@ -731,7 +529,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 if let Some(ty) = ty {
                     self.check_impl_trait(ty);
                 }
-                self.check_gat(generics, i.span);
                 false
             }
             _ => false,
diff --git a/compiler/rustc_ast_passes/src/lib.rs b/compiler/rustc_ast_passes/src/lib.rs
index f282ff251bda..f58fffc91720 100644
--- a/compiler/rustc_ast_passes/src/lib.rs
+++ b/compiler/rustc_ast_passes/src/lib.rs
@@ -9,9 +9,11 @@
 #![feature(if_let_guard)]
 #![feature(iter_is_partitioned)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![recursion_limit = "256"]
 
+#[macro_use]
+extern crate tracing;
+
 pub mod ast_validation;
 mod errors;
 pub mod feature_gate;
diff --git a/compiler/rustc_ast_passes/src/node_count.rs b/compiler/rustc_ast_passes/src/node_count.rs
index be3e46661bf0..fa42f87786de 100644
--- a/compiler/rustc_ast_passes/src/node_count.rs
+++ b/compiler/rustc_ast_passes/src/node_count.rs
@@ -63,9 +63,9 @@ impl<'ast> Visitor<'ast> for NodeCounter {
         self.count += 1;
         walk_generics(self, g)
     }
-    fn visit_fn(&mut self, fk: visit::FnKind<'_>, s: Span, _: NodeId) {
+    fn visit_fn(&mut self, fk: visit::FnKind<'_>, _: Span, _: NodeId) {
         self.count += 1;
-        walk_fn(self, fk, s)
+        walk_fn(self, fk)
     }
     fn visit_assoc_item(&mut self, ti: &AssocItem, ctxt: AssocCtxt) {
         self.count += 1;
@@ -115,9 +115,9 @@ impl<'ast> Visitor<'ast> for NodeCounter {
         self.count += 1;
         walk_use_tree(self, use_tree, id)
     }
-    fn visit_generic_args(&mut self, path_span: Span, generic_args: &GenericArgs) {
+    fn visit_generic_args(&mut self, generic_args: &GenericArgs) {
         self.count += 1;
-        walk_generic_args(self, path_span, generic_args)
+        walk_generic_args(self, generic_args)
     }
     fn visit_assoc_constraint(&mut self, constraint: &AssocConstraint) {
         self.count += 1;
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 8749a13c5dde..b87c6f78d728 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -11,8 +11,8 @@ use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_ast::util::classify;
 use rustc_ast::util::comments::{gather_comments, Comment, CommentStyle};
 use rustc_ast::util::parser;
-use rustc_ast::{self as ast, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
-use rustc_ast::{attr, Term};
+use rustc_ast::{self as ast, BlockCheckMode, Mutability, PatKind, RangeEnd, RangeSyntax};
+use rustc_ast::{attr, BindingAnnotation, ByRef, Term};
 use rustc_ast::{GenericArg, MacArgs, MacArgsEq};
 use rustc_ast::{GenericBound, SelfKind, TraitBoundModifier};
 use rustc_ast::{InlineAsmOperand, InlineAsmRegOrRegClass};
@@ -22,6 +22,7 @@ use rustc_span::source_map::{SourceMap, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, IdentPrinter, Symbol};
 use rustc_span::{BytePos, FileName, Span};
 
+use rustc_ast::attr::AttrIdGenerator;
 use std::borrow::Cow;
 
 pub use self::delimited::IterDelimited;
@@ -107,6 +108,7 @@ pub fn print_crate<'a>(
     ann: &'a dyn PpAnn,
     is_expanded: bool,
     edition: Edition,
+    g: &AttrIdGenerator,
 ) -> String {
     let mut s =
         State { s: pp::Printer::new(), comments: Some(Comments::new(sm, filename, input)), ann };
@@ -120,7 +122,7 @@ pub fn print_crate<'a>(
         // `#![feature(prelude_import)]`
         let pi_nested = attr::mk_nested_word_item(Ident::with_dummy_span(sym::prelude_import));
         let list = attr::mk_list_item(Ident::with_dummy_span(sym::feature), vec![pi_nested]);
-        let fake_attr = attr::mk_attr_inner(list);
+        let fake_attr = attr::mk_attr_inner(g, list);
         s.print_attribute(&fake_attr);
 
         // Currently, in Rust 2018 we don't have `extern crate std;` at the crate
@@ -128,7 +130,7 @@ pub fn print_crate<'a>(
         if edition == Edition::Edition2015 {
             // `#![no_std]`
             let no_std_meta = attr::mk_word_item(Ident::with_dummy_span(sym::no_std));
-            let fake_attr = attr::mk_attr_inner(no_std_meta);
+            let fake_attr = attr::mk_attr_inner(g, no_std_meta);
             s.print_attribute(&fake_attr);
         }
     }
@@ -1399,16 +1401,12 @@ impl<'a> State<'a> {
         is that it doesn't matter */
         match pat.kind {
             PatKind::Wild => self.word("_"),
-            PatKind::Ident(binding_mode, ident, ref sub) => {
-                match binding_mode {
-                    ast::BindingMode::ByRef(mutbl) => {
-                        self.word_nbsp("ref");
-                        self.print_mutability(mutbl, false);
-                    }
-                    ast::BindingMode::ByValue(ast::Mutability::Not) => {}
-                    ast::BindingMode::ByValue(ast::Mutability::Mut) => {
-                        self.word_nbsp("mut");
-                    }
+            PatKind::Ident(BindingAnnotation(by_ref, mutbl), ident, ref sub) => {
+                if by_ref == ByRef::Yes {
+                    self.word_nbsp("ref");
+                }
+                if mutbl == Mutability::Mut {
+                    self.word_nbsp("mut");
                 }
                 self.print_ident(ident);
                 if let Some(ref p) = *sub {
@@ -1487,12 +1485,10 @@ impl<'a> State<'a> {
             }
             PatKind::Ref(ref inner, mutbl) => {
                 self.word("&");
-                if mutbl == ast::Mutability::Mut {
+                if mutbl == Mutability::Mut {
                     self.word("mut ");
                 }
-                if let PatKind::Ident(ast::BindingMode::ByValue(ast::Mutability::Mut), ..) =
-                    inner.kind
-                {
+                if let PatKind::Ident(ast::BindingAnnotation::MUT, ..) = inner.kind {
                     self.popen();
                     self.print_pat(inner);
                     self.pclose();
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/item.rs b/compiler/rustc_ast_pretty/src/pprust/state/item.rs
index bd87987010e8..54bac29a6cee 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state/item.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state/item.rs
@@ -218,6 +218,8 @@ impl<'a> State<'a> {
             ast::ItemKind::GlobalAsm(ref asm) => {
                 self.head(visibility_qualified(&item.vis, "global_asm!"));
                 self.print_inline_asm(asm);
+                self.word(";");
+                self.end();
                 self.end();
             }
             ast::ItemKind::TyAlias(box ast::TyAlias {
diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index 65edab78ce74..753f62dd589d 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -15,6 +15,18 @@ use std::num::NonZeroU32;
 
 use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause};
 
+/// The version placeholder that recently stabilized features contain inside the
+/// `since` field of the `#[stable]` attribute.
+///
+/// For more, see [this pull request](https://github.com/rust-lang/rust/pull/100591).
+pub const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION";
+
+pub fn rust_version_symbol() -> Symbol {
+    let version = option_env!("CFG_VERSION").unwrap_or("<current>");
+    let version = version.split(' ').next().unwrap();
+    Symbol::intern(&version)
+}
+
 pub fn is_builtin_attr(attr: &Attribute) -> bool {
     attr.is_doc_comment() || attr.ident().filter(|ident| is_builtin_attr_name(ident.name)).is_some()
 }
@@ -57,7 +69,12 @@ fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) {
             sess.emit_err(session_diagnostics::MultipleStabilityLevels { span });
         }
         AttrError::UnsupportedLiteral(reason, is_bytestr) => {
-            sess.emit_err(session_diagnostics::UnsupportedLiteral { span, reason, is_bytestr });
+            sess.emit_err(session_diagnostics::UnsupportedLiteral {
+                span,
+                reason,
+                is_bytestr,
+                start_point_span: sess.source_map().start_point(span),
+            });
         }
     }
 }
@@ -483,6 +500,10 @@ where
                         }
                     }
 
+                    if let Some(s) = since && s.as_str() == VERSION_PLACEHOLDER {
+                        since = Some(rust_version_symbol());
+                    }
+
                     match (feature, since) {
                         (Some(feature), Some(since)) => {
                             let level = Stable { since, allowed_through_unstable_modules: false };
@@ -1028,18 +1049,16 @@ pub fn parse_repr_attr(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
                                 &name,
                             ),
                         });
-                    } else {
-                        if matches!(
-                            meta_item.name_or_empty(),
-                            sym::C | sym::simd | sym::transparent
-                        ) || int_type_of_word(meta_item.name_or_empty()).is_some()
-                        {
-                            recognised = true;
-                            sess.emit_err(session_diagnostics::InvalidReprHintNoValue {
-                                span: meta_item.span,
-                                name: meta_item.name_or_empty().to_ident_string(),
-                            });
-                        }
+                    } else if matches!(
+                        meta_item.name_or_empty(),
+                        sym::C | sym::simd | sym::transparent
+                    ) || int_type_of_word(meta_item.name_or_empty()).is_some()
+                    {
+                        recognised = true;
+                        sess.emit_err(session_diagnostics::InvalidReprHintNoValue {
+                            span: meta_item.span,
+                            name: meta_item.name_or_empty().to_ident_string(),
+                        });
                     }
                 } else if let MetaItemKind::List(_) = meta_item.kind {
                     if meta_item.has_name(sym::align) {
diff --git a/compiler/rustc_attr/src/lib.rs b/compiler/rustc_attr/src/lib.rs
index 053f848aacbf..4580ffcc6d8b 100644
--- a/compiler/rustc_attr/src/lib.rs
+++ b/compiler/rustc_attr/src/lib.rs
@@ -5,7 +5,6 @@
 //! to this crate.
 
 #![feature(let_chains)]
-#![feature(let_else)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
diff --git a/compiler/rustc_attr/src/session_diagnostics.rs b/compiler/rustc_attr/src/session_diagnostics.rs
index 25cd960dbf1d..d3e9a16a9a80 100644
--- a/compiler/rustc_attr/src/session_diagnostics.rs
+++ b/compiler/rustc_attr/src/session_diagnostics.rs
@@ -1,21 +1,22 @@
 use std::num::IntErrorKind;
 
 use rustc_ast as ast;
-use rustc_errors::{error_code, fluent, Applicability, DiagnosticBuilder, ErrorGuaranteed};
-use rustc_macros::SessionDiagnostic;
-use rustc_session::{parse::ParseSess, SessionDiagnostic};
+use rustc_errors::{
+    error_code, fluent, Applicability, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic,
+};
+use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 
 use crate::UnsupportedLiteralReason;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::expected_one_cfg_pattern, code = "E0536")]
 pub(crate) struct ExpectedOneCfgPattern {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::invalid_predicate, code = "E0537")]
 pub(crate) struct InvalidPredicate {
     #[primary_span]
@@ -24,7 +25,7 @@ pub(crate) struct InvalidPredicate {
     pub predicate: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::multiple_item, code = "E0538")]
 pub(crate) struct MultipleItem {
     #[primary_span]
@@ -33,7 +34,7 @@ pub(crate) struct MultipleItem {
     pub item: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::incorrect_meta_item, code = "E0539")]
 pub(crate) struct IncorrectMetaItem {
     #[primary_span]
@@ -48,10 +49,10 @@ pub(crate) struct UnknownMetaItem<'a> {
 }
 
 // Manual implementation to be able to format `expected` items correctly.
-impl<'a> SessionDiagnostic<'a> for UnknownMetaItem<'_> {
-    fn into_diagnostic(self, sess: &'a ParseSess) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+impl<'a> IntoDiagnostic<'a> for UnknownMetaItem<'_> {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         let expected = self.expected.iter().map(|name| format!("`{}`", name)).collect::<Vec<_>>();
-        let mut diag = sess.span_diagnostic.struct_span_err_with_code(
+        let mut diag = handler.struct_span_err_with_code(
             self.span,
             fluent::attr::unknown_meta_item,
             error_code!(E0541),
@@ -63,28 +64,28 @@ impl<'a> SessionDiagnostic<'a> for UnknownMetaItem<'_> {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::missing_since, code = "E0542")]
 pub(crate) struct MissingSince {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::missing_note, code = "E0543")]
 pub(crate) struct MissingNote {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::multiple_stability_levels, code = "E0544")]
 pub(crate) struct MultipleStabilityLevels {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::invalid_issue_string, code = "E0545")]
 pub(crate) struct InvalidIssueString {
     #[primary_span]
@@ -96,7 +97,7 @@ pub(crate) struct InvalidIssueString {
 
 // The error kinds of `IntErrorKind` are duplicated here in order to allow the messages to be
 // translatable.
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum InvalidIssueStringCause {
     #[label(attr::must_not_be_zero)]
     MustNotBeZero {
@@ -142,21 +143,21 @@ impl InvalidIssueStringCause {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::missing_feature, code = "E0546")]
 pub(crate) struct MissingFeature {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::non_ident_feature, code = "E0546")]
 pub(crate) struct NonIdentFeature {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::missing_issue, code = "E0547")]
 pub(crate) struct MissingIssue {
     #[primary_span]
@@ -165,7 +166,7 @@ pub(crate) struct MissingIssue {
 
 // FIXME: This diagnostic is identical to `IncorrectMetaItem`, barring the error code. Consider
 // changing this to `IncorrectMetaItem`. See #51489.
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::incorrect_meta_item, code = "E0551")]
 pub(crate) struct IncorrectMetaItem2 {
     #[primary_span]
@@ -174,14 +175,14 @@ pub(crate) struct IncorrectMetaItem2 {
 
 // FIXME: Why is this the same error code as `InvalidReprHintNoParen` and `InvalidReprHintNoValue`?
 // It is more similar to `IncorrectReprFormatGeneric`.
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::incorrect_repr_format_packed_one_or_zero_arg, code = "E0552")]
 pub(crate) struct IncorrectReprFormatPackedOneOrZeroArg {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::invalid_repr_hint_no_paren, code = "E0552")]
 pub(crate) struct InvalidReprHintNoParen {
     #[primary_span]
@@ -190,7 +191,7 @@ pub(crate) struct InvalidReprHintNoParen {
     pub name: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::invalid_repr_hint_no_value, code = "E0552")]
 pub(crate) struct InvalidReprHintNoValue {
     #[primary_span]
@@ -204,11 +205,12 @@ pub(crate) struct UnsupportedLiteral {
     pub span: Span,
     pub reason: UnsupportedLiteralReason,
     pub is_bytestr: bool,
+    pub start_point_span: Span,
 }
 
-impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral {
-    fn into_diagnostic(self, sess: &'a ParseSess) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        let mut diag = sess.span_diagnostic.struct_span_err_with_code(
+impl<'a> IntoDiagnostic<'a> for UnsupportedLiteral {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+        let mut diag = handler.struct_span_err_with_code(
             self.span,
             match self.reason {
                 UnsupportedLiteralReason::Generic => fluent::attr::unsupported_literal_generic,
@@ -224,7 +226,7 @@ impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral {
         );
         if self.is_bytestr {
             diag.span_suggestion(
-                sess.source_map().start_point(self.span),
+                self.start_point_span,
                 fluent::attr::unsupported_literal_suggestion,
                 "",
                 Applicability::MaybeIncorrect,
@@ -234,7 +236,7 @@ impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::invalid_repr_align_need_arg, code = "E0589")]
 pub(crate) struct InvalidReprAlignNeedArg {
     #[primary_span]
@@ -242,7 +244,7 @@ pub(crate) struct InvalidReprAlignNeedArg {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::invalid_repr_generic, code = "E0589")]
 pub(crate) struct InvalidReprGeneric<'a> {
     #[primary_span]
@@ -252,14 +254,14 @@ pub(crate) struct InvalidReprGeneric<'a> {
     pub error_part: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::incorrect_repr_format_align_one_arg, code = "E0693")]
 pub(crate) struct IncorrectReprFormatAlignOneArg {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::incorrect_repr_format_generic, code = "E0693")]
 pub(crate) struct IncorrectReprFormatGeneric<'a> {
     #[primary_span]
@@ -271,7 +273,7 @@ pub(crate) struct IncorrectReprFormatGeneric<'a> {
     pub cause: Option<IncorrectReprFormatGenericCause<'a>>,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum IncorrectReprFormatGenericCause<'a> {
     #[suggestion(attr::suggestion, code = "{name}({int})", applicability = "machine-applicable")]
     Int {
@@ -314,28 +316,28 @@ impl<'a> IncorrectReprFormatGenericCause<'a> {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::rustc_promotable_pairing, code = "E0717")]
 pub(crate) struct RustcPromotablePairing {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::rustc_allowed_unstable_pairing, code = "E0789")]
 pub(crate) struct RustcAllowedUnstablePairing {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::cfg_predicate_identifier)]
 pub(crate) struct CfgPredicateIdentifier {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::deprecated_item_suggestion)]
 pub(crate) struct DeprecatedItemSuggestion {
     #[primary_span]
@@ -348,21 +350,21 @@ pub(crate) struct DeprecatedItemSuggestion {
     pub details: (),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::expected_single_version_literal)]
 pub(crate) struct ExpectedSingleVersionLiteral {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::expected_version_literal)]
 pub(crate) struct ExpectedVersionLiteral {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::expects_feature_list)]
 pub(crate) struct ExpectsFeatureList {
     #[primary_span]
@@ -371,7 +373,7 @@ pub(crate) struct ExpectsFeatureList {
     pub name: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::expects_features)]
 pub(crate) struct ExpectsFeatures {
     #[primary_span]
@@ -380,14 +382,14 @@ pub(crate) struct ExpectsFeatures {
     pub name: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::soft_no_args)]
 pub(crate) struct SoftNoArgs {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(attr::unknown_version_literal)]
 pub(crate) struct UnknownVersionLiteral {
     #[primary_span]
diff --git a/compiler/rustc_borrowck/src/constraints/mod.rs b/compiler/rustc_borrowck/src/constraints/mod.rs
index c94dfe39b690..df04128135b8 100644
--- a/compiler/rustc_borrowck/src/constraints/mod.rs
+++ b/compiler/rustc_borrowck/src/constraints/mod.rs
@@ -21,10 +21,7 @@ pub(crate) struct OutlivesConstraintSet<'tcx> {
 
 impl<'tcx> OutlivesConstraintSet<'tcx> {
     pub(crate) fn push(&mut self, constraint: OutlivesConstraint<'tcx>) {
-        debug!(
-            "OutlivesConstraintSet::push({:?}: {:?} @ {:?}",
-            constraint.sup, constraint.sub, constraint.locations
-        );
+        debug!("OutlivesConstraintSet::push({:?})", constraint);
         if constraint.sup == constraint.sub {
             // 'a: 'a is pretty uninteresting
             return;
@@ -73,7 +70,7 @@ impl<'tcx> Index<OutlivesConstraintIndex> for OutlivesConstraintSet<'tcx> {
     }
 }
 
-#[derive(Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq)]
 pub struct OutlivesConstraint<'tcx> {
     // NB. The ordering here is not significant for correctness, but
     // it is for convenience. Before we dump the constraints in the
diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs
index 816288eb50b2..9f7a4d49989a 100644
--- a/compiler/rustc_borrowck/src/dataflow.rs
+++ b/compiler/rustc_borrowck/src/dataflow.rs
@@ -391,7 +391,7 @@ impl<'tcx> rustc_mir_dataflow::GenKillAnalysis<'tcx> for Borrows<'_, 'tcx> {
             | mir::StatementKind::Retag { .. }
             | mir::StatementKind::AscribeUserType(..)
             | mir::StatementKind::Coverage(..)
-            | mir::StatementKind::CopyNonOverlapping(..)
+            | mir::StatementKind::Intrinsic(..)
             | mir::StatementKind::Nop => {}
         }
     }
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 5971f7623f21..a1b34e94dbfe 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -16,7 +16,7 @@ use rustc_middle::mir::{
     FakeReadCause, LocalDecl, LocalInfo, LocalKind, Location, Operand, Place, PlaceRef,
     ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind, VarBindingForm,
 };
-use rustc_middle::ty::{self, subst::Subst, suggest_constraining_type_params, PredicateKind, Ty};
+use rustc_middle::ty::{self, suggest_constraining_type_params, PredicateKind, Ty};
 use rustc_mir_dataflow::move_paths::{InitKind, MoveOutIndex, MovePathIndex};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
@@ -198,7 +198,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     move_span,
                     move_spans,
                     *moved_place,
-                    Some(used_place),
                     partially_str,
                     loop_message,
                     move_msg,
@@ -258,7 +257,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             let ty = place.ty(self.body, self.infcx.tcx).ty;
 
             // If we're in pattern, we do nothing in favor of the previous suggestion (#80913).
-            if is_loop_move & !in_pattern {
+            // Same for if we're in a loop, see #101119.
+            if is_loop_move & !in_pattern && !matches!(use_spans, UseSpans::ClosureUse { .. }) {
                 if let ty::Ref(_, _, hir::Mutability::Mut) = ty.kind() {
                     // We have a `&mut` ref, we need to reborrow on each iteration (#62112).
                     err.span_suggestion_verbose(
@@ -368,6 +368,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let mut visitor = ConditionVisitor { spans: &spans, name: &name, errors: vec![] };
         visitor.visit_body(&body);
 
+        let mut show_assign_sugg = false;
         let isnt_initialized = if let InitializationRequiringAction::PartialAssignment
         | InitializationRequiringAction::Assignment = desired_action
         {
@@ -395,6 +396,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             .count()
             == 0
         {
+            show_assign_sugg = true;
             "isn't initialized"
         } else {
             "is possibly-uninitialized"
@@ -445,10 +447,78 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 }
             }
         }
+
         err.span_label(decl_span, "binding declared here but left uninitialized");
+        if show_assign_sugg {
+            struct LetVisitor {
+                decl_span: Span,
+                sugg_span: Option<Span>,
+            }
+
+            impl<'v> Visitor<'v> for LetVisitor {
+                fn visit_stmt(&mut self, ex: &'v hir::Stmt<'v>) {
+                    if self.sugg_span.is_some() {
+                        return;
+                    }
+                    if let hir::StmtKind::Local(hir::Local {
+                            span, ty, init: None, ..
+                        }) = &ex.kind && span.contains(self.decl_span) {
+                            self.sugg_span = ty.map_or(Some(self.decl_span), |ty| Some(ty.span));
+                    }
+                    hir::intravisit::walk_stmt(self, ex);
+                }
+            }
+
+            let mut visitor = LetVisitor { decl_span, sugg_span: None };
+            visitor.visit_body(&body);
+            if let Some(span) = visitor.sugg_span {
+                self.suggest_assign_value(&mut err, moved_place, span);
+            }
+        }
         err
     }
 
+    fn suggest_assign_value(
+        &self,
+        err: &mut Diagnostic,
+        moved_place: PlaceRef<'tcx>,
+        sugg_span: Span,
+    ) {
+        let ty = moved_place.ty(self.body, self.infcx.tcx).ty;
+        debug!("ty: {:?}, kind: {:?}", ty, ty.kind());
+
+        let tcx = self.infcx.tcx;
+        let implements_default = |ty, param_env| {
+            let Some(default_trait) = tcx.get_diagnostic_item(sym::Default) else {
+                return false;
+            };
+            tcx.infer_ctxt().enter(|infcx| {
+                infcx
+                    .type_implements_trait(default_trait, ty, ty::List::empty(), param_env)
+                    .may_apply()
+            })
+        };
+
+        let assign_value = match ty.kind() {
+            ty::Bool => "false",
+            ty::Float(_) => "0.0",
+            ty::Int(_) | ty::Uint(_) => "0",
+            ty::Never | ty::Error(_) => "",
+            ty::Adt(def, _) if Some(def.did()) == tcx.get_diagnostic_item(sym::Vec) => "vec![]",
+            ty::Adt(_, _) if implements_default(ty, self.param_env) => "Default::default()",
+            _ => "todo!()",
+        };
+
+        if !assign_value.is_empty() {
+            err.span_suggestion_verbose(
+                sugg_span.shrink_to_hi(),
+                format!("consider assigning a value"),
+                format!(" = {}", assign_value),
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
+
     fn suggest_borrow_fn_like(
         &self,
         err: &mut Diagnostic,
@@ -2145,7 +2215,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             }
                             StorageDeadOrDrop::Destructor(_) => kind,
                         },
-                        ProjectionElem::Field(..) | ProjectionElem::Downcast(..) => {
+                        ProjectionElem::OpaqueCast { .. }
+                        | ProjectionElem::Field(..)
+                        | ProjectionElem::Downcast(..) => {
                             match place_ty.ty.kind() {
                                 ty::Adt(def, _) if def.has_dtor(tcx) => {
                                     // Report the outermost adt with a destructor
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index 2f61849c383c..1c01e78abd42 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -15,7 +15,7 @@ use rustc_middle::ty::{self, RegionVid, TyCtxt};
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{sym, DesugaringKind, Span};
 
-use crate::region_infer::BlameConstraint;
+use crate::region_infer::{BlameConstraint, ExtraConstraintInfo};
 use crate::{
     borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt,
     WriteKind,
@@ -38,6 +38,7 @@ pub(crate) enum BorrowExplanation<'tcx> {
         span: Span,
         region_name: RegionName,
         opt_place_desc: Option<String>,
+        extra_info: Vec<ExtraConstraintInfo>,
     },
     Unexplained,
 }
@@ -243,6 +244,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
                 ref region_name,
                 ref opt_place_desc,
                 from_closure: _,
+                ref extra_info,
             } => {
                 region_name.highlight_region_name(err);
 
@@ -268,6 +270,14 @@ impl<'tcx> BorrowExplanation<'tcx> {
                     );
                 };
 
+                for extra in extra_info {
+                    match extra {
+                        ExtraConstraintInfo::PlaceholderFromPredicate(span) => {
+                            err.span_note(*span, format!("due to current limitations in the borrow checker, this implies a `'static` lifetime"));
+                        }
+                    }
+                }
+
                 self.add_lifetime_bound_suggestion_to_diagnostic(err, &category, span, region_name);
             }
             _ => {}
@@ -309,18 +319,17 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         &self,
         borrow_region: RegionVid,
         outlived_region: RegionVid,
-    ) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>) {
-        let BlameConstraint { category, from_closure, cause, variance_info: _ } =
-            self.regioncx.best_blame_constraint(
-                &self.body,
-                borrow_region,
-                NllRegionVariableOrigin::FreeRegion,
-                |r| self.regioncx.provides_universal_region(r, borrow_region, outlived_region),
-            );
+    ) -> (ConstraintCategory<'tcx>, bool, Span, Option<RegionName>, Vec<ExtraConstraintInfo>) {
+        let (blame_constraint, extra_info) = self.regioncx.best_blame_constraint(
+            borrow_region,
+            NllRegionVariableOrigin::FreeRegion,
+            |r| self.regioncx.provides_universal_region(r, borrow_region, outlived_region),
+        );
+        let BlameConstraint { category, from_closure, cause, .. } = blame_constraint;
 
         let outlived_fr_name = self.give_region_a_name(outlived_region);
 
-        (category, from_closure, cause.span, outlived_fr_name)
+        (category, from_closure, cause.span, outlived_fr_name, extra_info)
     }
 
     /// Returns structured explanation for *why* the borrow contains the
@@ -392,7 +401,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
             None => {
                 if let Some(region) = self.to_error_region_vid(borrow_region_vid) {
-                    let (category, from_closure, span, region_name) =
+                    let (category, from_closure, span, region_name, extra_info) =
                         self.free_region_constraint_info(borrow_region_vid, region);
                     if let Some(region_name) = region_name {
                         let opt_place_desc = self.describe_place(borrow.borrowed_place.as_ref());
@@ -402,6 +411,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             span,
                             region_name,
                             opt_place_desc,
+                            extra_info,
                         }
                     } else {
                         debug!("Could not generate a region name");
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index 683084cf09d4..7ccb679d88b2 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -237,6 +237,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 }
                 ProjectionElem::Downcast(..) if opt.including_downcast => return None,
                 ProjectionElem::Downcast(..) => (),
+                ProjectionElem::OpaqueCast(..) => (),
                 ProjectionElem::Field(field, _ty) => {
                     // FIXME(project-rfc_2229#36): print capture precisely here.
                     if let Some(field) = self.is_upvar_field_projection(PlaceRef {
@@ -317,6 +318,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     PlaceRef { local, projection: proj_base }.ty(self.body, self.infcx.tcx)
                 }
                 ProjectionElem::Downcast(..) => place.ty(self.body, self.infcx.tcx),
+                ProjectionElem::OpaqueCast(ty) => PlaceTy::from_ty(*ty),
                 ProjectionElem::Field(_, field_type) => PlaceTy::from_ty(*field_type),
             },
         };
@@ -970,7 +972,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         move_span: Span,
         move_spans: UseSpans<'tcx>,
         moved_place: Place<'tcx>,
-        used_place: Option<PlaceRef<'tcx>>,
         partially_str: &str,
         loop_message: &str,
         move_msg: &str,
@@ -1058,9 +1059,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 place_name, partially_str, loop_message
                             ),
                         );
-                        // If we have a `&mut` ref, we need to reborrow.
-                        if let Some(ty::Ref(_, _, hir::Mutability::Mut)) = used_place
-                            .map(|used_place| used_place.ty(self.body, self.infcx.tcx).ty.kind())
+                        // If the moved place was a `&mut` ref, then we can
+                        // suggest to reborrow it where it was moved, so it
+                        // will still be valid by the time we get to the usage.
+                        if let ty::Ref(_, _, hir::Mutability::Mut) =
+                            moved_place.ty(self.body, self.infcx.tcx).ty.kind()
                         {
                             // If we are in a loop this will be suggested later.
                             if !is_loop_move {
diff --git a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
index 16c2f9ccc6aa..5a47f45677ec 100644
--- a/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
@@ -360,7 +360,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
                 diag.span_label(upvar_span, "captured outer variable");
                 diag.span_label(
-                    self.body.span,
+                    self.infcx.tcx.def_span(def_id),
                     format!("captured by this `{closure_kind}` closure"),
                 );
 
@@ -401,7 +401,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         };
         if let Some(use_spans) = use_spans {
             self.explain_captures(
-                &mut err, span, span, use_spans, move_place, None, "", "", "", false, true,
+                &mut err, span, span, use_spans, move_place, "", "", "", false, true,
             );
         }
         err
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index dd9590016b99..8ad40c0aa0a5 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -9,10 +9,7 @@ use rustc_middle::mir::{Mutability, Place, PlaceRef, ProjectionElem};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::{
     hir::place::PlaceBase,
-    mir::{
-        self, BindingForm, ClearCrossCrate, ImplicitSelfKind, Local, LocalDecl, LocalInfo,
-        LocalKind, Location,
-    },
+    mir::{self, BindingForm, ClearCrossCrate, Local, LocalDecl, LocalInfo, LocalKind, Location},
 };
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, Symbol};
@@ -172,6 +169,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         ..,
                         ProjectionElem::Index(_)
                         | ProjectionElem::ConstantIndex { .. }
+                        | ProjectionElem::OpaqueCast { .. }
                         | ProjectionElem::Subslice { .. }
                         | ProjectionElem::Downcast(..),
                     ],
@@ -312,7 +310,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     && !matches!(
                         decl.local_info,
                         Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(
-                            ImplicitSelfKind::MutRef
+                            hir::ImplicitSelfKind::MutRef
                         ))))
                     )
                 {
@@ -367,7 +365,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
                 if let Some(Node::Pat(pat)) = self.infcx.tcx.hir().find(upvar_hir_id)
                     && let hir::PatKind::Binding(
-                        hir::BindingAnnotation::Unannotated,
+                        hir::BindingAnnotation::NONE,
                         _,
                         upvar_ident,
                         _,
@@ -711,8 +709,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                             Applicability::MachineApplicable,
                         );
                         self.suggested = true;
-                    } else if let hir::ExprKind::MethodCall(_path, args @ [_, ..], sp) = expr.kind
-                        && let hir::ExprKind::Index(val, index) = args[0].kind
+                    } else if let hir::ExprKind::MethodCall(_path, receiver, _, sp) = expr.kind
+                        && let hir::ExprKind::Index(val, index) = receiver.kind
                         && expr.span == self.assign_span
                     {
                         // val[index].path(args..);
@@ -724,7 +722,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                     ".get_mut(".to_string(),
                                 ),
                                 (
-                                    index.span.shrink_to_hi().with_hi(args[0].span.hi()),
+                                    index.span.shrink_to_hi().with_hi(receiver.span.hi()),
                                     ").map(|val| val".to_string(),
                                 ),
                                 (sp.shrink_to_hi(), ")".to_string()),
@@ -911,11 +909,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                                         [
                                                             Expr {
                                                                 kind:
-                                                                    MethodCall(
-                                                                        path_segment,
-                                                                        _args,
-                                                                        span,
-                                                                    ),
+                                                                    MethodCall(path_segment, _, _, span),
                                                                 hir_id,
                                                                 ..
                                                             },
@@ -935,10 +929,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 _,
             ) = hir_map.body(fn_body_id).value.kind
             {
-                let opt_suggestions = path_segment
-                    .hir_id
-                    .map(|path_hir_id| self.infcx.tcx.typeck(path_hir_id.owner))
-                    .and_then(|typeck| typeck.type_dependent_def_id(*hir_id))
+                let opt_suggestions = self
+                    .infcx
+                    .tcx
+                    .typeck(path_segment.hir_id.owner.def_id)
+                    .type_dependent_def_id(*hir_id)
                     .and_then(|def_id| self.infcx.tcx.impl_of_method(def_id))
                     .map(|def_id| self.infcx.tcx.associated_items(def_id))
                     .map(|assoc_items| {
@@ -976,6 +971,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
         let hir = self.infcx.tcx.hir();
         let closure_id = self.mir_hir_id();
+        let closure_span = self.infcx.tcx.def_span(self.mir_def_id());
         let fn_call_id = hir.get_parent_node(closure_id);
         let node = hir.get(fn_call_id);
         let def_id = hir.enclosing_body_owner(fn_call_id);
@@ -1027,7 +1023,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 if let Some(span) = arg {
                     err.span_label(span, "change this to accept `FnMut` instead of `Fn`");
                     err.span_label(func.span, "expects `Fn` instead of `FnMut`");
-                    err.span_label(self.body.span, "in this closure");
+                    err.span_label(closure_span, "in this closure");
                     look_at_return = false;
                 }
             }
@@ -1036,7 +1032,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         if look_at_return && hir.get_return_block(closure_id).is_some() {
             // ...otherwise we are probably in the tail expression of the function, point at the
             // return type.
-            match hir.get_by_def_id(hir.get_parent_item(fn_call_id)) {
+            match hir.get_by_def_id(hir.get_parent_item(fn_call_id).def_id) {
                 hir::Node::Item(hir::Item { ident, kind: hir::ItemKind::Fn(sig, ..), .. })
                 | hir::Node::TraitItem(hir::TraitItem {
                     ident,
@@ -1053,7 +1049,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         sig.decl.output.span(),
                         "change this to return `FnMut` instead of `Fn`",
                     );
-                    err.span_label(self.body.span, "in this closure");
+                    err.span_label(closure_span, "in this closure");
                 }
                 _ => {}
             }
@@ -1077,7 +1073,7 @@ fn mut_borrow_of_mutable_ref(local_decl: &LocalDecl<'_>, local_name: Option<Symb
             //
             // Deliberately fall into this case for all implicit self types,
             // so that we don't fall in to the next case with them.
-            *kind == mir::ImplicitSelfKind::MutRef
+            *kind == hir::ImplicitSelfKind::MutRef
         }
         _ if Some(kw::SelfLower) == local_name => {
             // Otherwise, check if the name is the `self` keyword - in which case
diff --git a/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs b/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
index d359d7efb626..35c3df768995 100644
--- a/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
@@ -6,7 +6,6 @@ use rustc_errors::Diagnostic;
 use rustc_middle::ty::RegionVid;
 use smallvec::SmallVec;
 use std::collections::BTreeMap;
-use tracing::debug;
 
 use crate::MirBorrowckCtxt;
 
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
index 00fdf331ca60..43d67bfa7299 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -31,7 +31,7 @@ use crate::session_diagnostics::{
 };
 
 use super::{OutlivesSuggestionBuilder, RegionName};
-use crate::region_infer::BlameConstraint;
+use crate::region_infer::{BlameConstraint, ExtraConstraintInfo};
 use crate::{
     nll::ConstraintDescription,
     region_infer::{values::RegionElement, TypeTest},
@@ -234,7 +234,6 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
                     // Find the code to blame for the fact that `longer_fr` outlives `error_fr`.
                     let (_, cause) = self.regioncx.find_outlives_blame_span(
-                        &self.body,
                         longer_fr,
                         NllRegionVariableOrigin::Placeholder(placeholder),
                         error_vid,
@@ -282,7 +281,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let tcx = self.infcx.tcx;
         match tcx.hir().get_if_local(def_id) {
             Some(Node::ImplItem(impl_item)) => {
-                match tcx.hir().find_by_def_id(tcx.hir().get_parent_item(impl_item.hir_id())) {
+                match tcx.hir().find_by_def_id(tcx.hir().get_parent_item(impl_item.hir_id()).def_id)
+                {
                     Some(Node::Item(Item {
                         kind: ItemKind::Impl(hir::Impl { self_ty, .. }),
                         ..
@@ -292,7 +292,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             }
             Some(Node::TraitItem(trait_item)) => {
                 let trait_did = tcx.hir().get_parent_item(trait_item.hir_id());
-                match tcx.hir().find_by_def_id(trait_did) {
+                match tcx.hir().find_by_def_id(trait_did.def_id) {
                     Some(Node::Item(Item { kind: ItemKind::Trait(..), .. })) => {
                         // The method being called is defined in the `trait`, but the `'static`
                         // obligation comes from the `impl`. Find that `impl` so that we can point
@@ -355,10 +355,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     ) {
         debug!("report_region_error(fr={:?}, outlived_fr={:?})", fr, outlived_fr);
 
-        let BlameConstraint { category, cause, variance_info, from_closure: _ } =
-            self.regioncx.best_blame_constraint(&self.body, fr, fr_origin, |r| {
+        let (blame_constraint, extra_info) =
+            self.regioncx.best_blame_constraint(fr, fr_origin, |r| {
                 self.regioncx.provides_universal_region(r, fr, outlived_fr)
             });
+        let BlameConstraint { category, cause, variance_info, .. } = blame_constraint;
 
         debug!("report_region_error: category={:?} {:?} {:?}", category, cause, variance_info);
 
@@ -467,6 +468,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             }
         }
 
+        for extra in extra_info {
+            match extra {
+                ExtraConstraintInfo::PlaceholderFromPredicate(span) => {
+                    diag.span_note(span, format!("due to current limitations in the borrow checker, this implies a `'static` lifetime"));
+                }
+            }
+        }
+
         self.buffer_error(diag);
     }
 
@@ -558,6 +567,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     /// LL |     ref_obj(x)
     ///    |     ^^^^^^^^^^ `x` escapes the function body here
     /// ```
+    #[instrument(level = "debug", skip(self))]
     fn report_escaping_data_error(
         &self,
         errci: &ErrorConstraintInfo<'tcx>,
@@ -900,10 +910,13 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let mut closure_span = None::<rustc_span::Span>;
         match expr.kind {
             hir::ExprKind::MethodCall(.., args, _) => {
-                // only the first closre parameter of the method. args[0] is MethodCall PathSegment
-                for i in 1..args.len() {
-                    if let hir::ExprKind::Closure(..) = args[i].kind {
-                        closure_span = Some(args[i].span.shrink_to_lo());
+                for arg in args {
+                    if let hir::ExprKind::Closure(hir::Closure {
+                        capture_clause: hir::CaptureBy::Ref,
+                        ..
+                    }) = arg.kind
+                    {
+                        closure_span = Some(arg.span.shrink_to_lo());
                         break;
                     }
                 }
@@ -911,7 +924,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             hir::ExprKind::Block(blk, _) => {
                 if let Some(ref expr) = blk.expr {
                     // only when the block is a closure
-                    if let hir::ExprKind::Closure(..) = expr.kind {
+                    if let hir::ExprKind::Closure(hir::Closure {
+                        capture_clause: hir::CaptureBy::Ref,
+                        ..
+                    }) = expr.kind
+                    {
                         closure_span = Some(expr.span.shrink_to_lo());
                     }
                 }
@@ -921,7 +938,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         if let Some(closure_span) = closure_span {
             diag.span_suggestion_verbose(
                 closure_span,
-                format!("consider adding 'move' keyword before the nested closure"),
+                "consider adding 'move' keyword before the nested closure",
                 "move ",
                 Applicability::MaybeIncorrect,
             );
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_name.rs b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
index a87e8bd5ba16..419e6c817915 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
@@ -265,7 +265,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
     /// *user* has a name for. In that case, we'll be able to map
     /// `fr` to a `Region<'tcx>`, and that region will be one of
     /// named variants.
-    #[tracing::instrument(level = "trace", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn give_name_from_error_region(&self, fr: RegionVid) -> Option<RegionName> {
         let error_region = self.to_error_region(fr)?;
 
@@ -357,11 +357,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                 ty::BoundRegionKind::BrAnon(_) => None,
             },
 
-            ty::ReLateBound(..)
-            | ty::ReVar(..)
-            | ty::RePlaceholder(..)
-            | ty::ReEmpty(_)
-            | ty::ReErased => None,
+            ty::ReLateBound(..) | ty::ReVar(..) | ty::RePlaceholder(..) | ty::ReErased => None,
         }
     }
 
@@ -373,7 +369,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
     ///  | fn foo(x: &u32) { .. }
     ///           ------- fully elaborated type of `x` is `&'1 u32`
     /// ```
-    #[tracing::instrument(level = "trace", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn give_name_if_anonymous_region_appears_in_arguments(
         &self,
         fr: RegionVid,
@@ -662,7 +658,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
     ///  | let x = Some(&22);
     ///        - fully elaborated type of `x` is `Option<&'1 u32>`
     /// ```
-    #[tracing::instrument(level = "trace", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn give_name_if_anonymous_region_appears_in_upvars(&self, fr: RegionVid) -> Option<RegionName> {
         let upvar_index = self.regioncx.get_upvar_index_for_region(self.infcx.tcx, fr)?;
         let (upvar_name, upvar_span) = self.regioncx.get_upvar_name_and_span_for_region(
@@ -682,7 +678,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
     /// must be a closure since, in a free fn, such an argument would
     /// have to either also appear in an argument (if using elision)
     /// or be early bound (named, not in argument).
-    #[tracing::instrument(level = "trace", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn give_name_if_anonymous_region_appears_in_output(&self, fr: RegionVid) -> Option<RegionName> {
         let tcx = self.infcx.tcx;
         let hir = tcx.hir();
@@ -711,7 +707,8 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                         hir::AsyncGeneratorKind::Block => " of async block",
                         hir::AsyncGeneratorKind::Closure => " of async closure",
                         hir::AsyncGeneratorKind::Fn => {
-                            let parent_item = hir.get_by_def_id(hir.get_parent_item(mir_hir_id));
+                            let parent_item =
+                                hir.get_by_def_id(hir.get_parent_item(mir_hir_id).def_id);
                             let output = &parent_item
                                 .fn_decl()
                                 .expect("generator lowered from async fn should be in fn")
@@ -772,7 +769,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
     fn get_future_inner_return_ty(&self, hir_ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
         let hir = self.infcx.tcx.hir();
 
-        let hir::TyKind::OpaqueDef(id, _) = hir_ty.kind else {
+        let hir::TyKind::OpaqueDef(id, _, _) = hir_ty.kind else {
             span_bug!(
                 hir_ty.span,
                 "lowered return type of async fn is not OpaqueDef: {:?}",
@@ -814,7 +811,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "trace", skip(self))]
+    #[instrument(level = "trace", skip(self))]
     fn give_name_if_anonymous_region_appears_in_yield_ty(
         &self,
         fr: RegionVid,
diff --git a/compiler/rustc_borrowck/src/invalidation.rs b/compiler/rustc_borrowck/src/invalidation.rs
index ec521b1cf0af..3157f861d93b 100644
--- a/compiler/rustc_borrowck/src/invalidation.rs
+++ b/compiler/rustc_borrowck/src/invalidation.rs
@@ -1,6 +1,6 @@
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{BasicBlock, Body, Location, Place, Rvalue};
+use rustc_middle::mir::{self, BasicBlock, Body, Location, NonDivergingIntrinsic, Place, Rvalue};
 use rustc_middle::mir::{BorrowKind, Mutability, Operand};
 use rustc_middle::mir::{InlineAsmOperand, Terminator, TerminatorKind};
 use rustc_middle::mir::{Statement, StatementKind};
@@ -63,23 +63,24 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
             StatementKind::FakeRead(box (_, _)) => {
                 // Only relevant for initialized/liveness/safety checks.
             }
-            StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
+            StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(op)) => {
+                self.consume_operand(location, op);
+            }
+            StatementKind::Intrinsic(box NonDivergingIntrinsic::CopyNonOverlapping(mir::CopyNonOverlapping {
                 ref src,
                 ref dst,
                 ref count,
-            }) => {
+            })) => {
                 self.consume_operand(location, src);
                 self.consume_operand(location, dst);
                 self.consume_operand(location, count);
             }
-            StatementKind::Nop
+            // Only relevant for mir typeck
+            StatementKind::AscribeUserType(..)
+            // Doesn't have any language semantics
             | StatementKind::Coverage(..)
-            | StatementKind::AscribeUserType(..)
-            | StatementKind::Retag { .. }
-            | StatementKind::StorageLive(..) => {
-                // `Nop`, `AscribeUserType`, `Retag`, and `StorageLive` are irrelevant
-                // to borrow check.
-            }
+            // Does not actually affect borrowck
+            | StatementKind::StorageLive(..) => {}
             StatementKind::StorageDead(local) => {
                 self.access_place(
                     location,
@@ -88,7 +89,10 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
                     LocalMutationIsAllowed::Yes,
                 );
             }
-            StatementKind::Deinit(..) | StatementKind::SetDiscriminant { .. } => {
+            StatementKind::Nop
+            | StatementKind::Retag { .. }
+            | StatementKind::Deinit(..)
+            | StatementKind::SetDiscriminant { .. } => {
                 bug!("Statement not allowed in this MIR phase")
             }
         }
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 20c22575bd1f..a83840e10998 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -3,7 +3,6 @@
 #![allow(rustc::potential_query_instability)]
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
@@ -26,8 +25,8 @@ use rustc_index::bit_set::ChunkedBitSet;
 use rustc_index::vec::IndexVec;
 use rustc_infer::infer::{DefiningAnchor, InferCtxt, TyCtxtInferExt};
 use rustc_middle::mir::{
-    traversal, Body, ClearCrossCrate, Local, Location, Mutability, Operand, Place, PlaceElem,
-    PlaceRef, VarDebugInfoContents,
+    traversal, Body, ClearCrossCrate, Local, Location, Mutability, NonDivergingIntrinsic, Operand,
+    Place, PlaceElem, PlaceRef, VarDebugInfoContents,
 };
 use rustc_middle::mir::{AggregateKind, BasicBlock, BorrowCheckResult, BorrowKind};
 use rustc_middle::mir::{Field, ProjectionElem, Promoted, Rvalue, Statement, StatementKind};
@@ -134,7 +133,7 @@ fn mir_borrowck<'tcx>(
 
     let opt_closure_req = tcx
         .infer_ctxt()
-        .with_opaque_type_inference(DefiningAnchor::Bind(hir_owner))
+        .with_opaque_type_inference(DefiningAnchor::Bind(hir_owner.def_id))
         .enter(|infcx| {
             let input_body: &Body<'_> = &input_body.borrow();
             let promoted: &IndexVec<_, _> = &promoted.borrow();
@@ -591,22 +590,19 @@ impl<'cx, 'tcx> rustc_mir_dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtx
                     flow_state,
                 );
             }
-            StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
-                ..
-            }) => {
-                span_bug!(
+            StatementKind::Intrinsic(box ref kind) => match kind {
+                NonDivergingIntrinsic::Assume(op) => self.consume_operand(location, (op, span), flow_state),
+                NonDivergingIntrinsic::CopyNonOverlapping(..) => span_bug!(
                     span,
                     "Unexpected CopyNonOverlapping, should only appear after lower_intrinsics",
                 )
             }
-            StatementKind::Nop
+            // Only relevant for mir typeck
+            StatementKind::AscribeUserType(..)
+            // Doesn't have any language semantics
             | StatementKind::Coverage(..)
-            | StatementKind::AscribeUserType(..)
-            | StatementKind::Retag { .. }
-            | StatementKind::StorageLive(..) => {
-                // `Nop`, `AscribeUserType`, `Retag`, and `StorageLive` are irrelevant
-                // to borrow check.
-            }
+            // Does not actually affect borrowck
+            | StatementKind::StorageLive(..) => {}
             StatementKind::StorageDead(local) => {
                 self.access_place(
                     location,
@@ -616,7 +612,10 @@ impl<'cx, 'tcx> rustc_mir_dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtx
                     flow_state,
                 );
             }
-            StatementKind::Deinit(..) | StatementKind::SetDiscriminant { .. } => {
+            StatementKind::Nop
+            | StatementKind::Retag { .. }
+            | StatementKind::Deinit(..)
+            | StatementKind::SetDiscriminant { .. } => {
                 bug!("Statement not allowed in this MIR phase")
             }
         }
@@ -1781,6 +1780,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         for (place_base, elem) in place.iter_projections().rev() {
             match elem {
                 ProjectionElem::Index(_/*operand*/) |
+                ProjectionElem::OpaqueCast(_) |
                 ProjectionElem::ConstantIndex { .. } |
                 // assigning to P[i] requires P to be valid.
                 ProjectionElem::Downcast(_/*adt_def*/, _/*variant_idx*/) =>
@@ -2172,6 +2172,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     | ProjectionElem::Index(..)
                     | ProjectionElem::ConstantIndex { .. }
                     | ProjectionElem::Subslice { .. }
+                    | ProjectionElem::OpaqueCast { .. }
                     | ProjectionElem::Downcast(..) => {
                         let upvar_field_projection = self.is_upvar_field_projection(place);
                         if let Some(field) = upvar_field_projection {
diff --git a/compiler/rustc_borrowck/src/location.rs b/compiler/rustc_borrowck/src/location.rs
index 5ca3f2f4d033..877944d3d70c 100644
--- a/compiler/rustc_borrowck/src/location.rs
+++ b/compiler/rustc_borrowck/src/location.rs
@@ -86,8 +86,7 @@ impl LocationTable {
         let (block, &first_index) = self
             .statements_before_block
             .iter_enumerated()
-            .filter(|(_, first_index)| **first_index <= point_index)
-            .last()
+            .rfind(|&(_, &first_index)| first_index <= point_index)
             .unwrap();
 
         let statement_index = (point_index - first_index) / 2;
diff --git a/compiler/rustc_borrowck/src/nll.rs b/compiler/rustc_borrowck/src/nll.rs
index 0961203d76d7..12b2481cc790 100644
--- a/compiler/rustc_borrowck/src/nll.rs
+++ b/compiler/rustc_borrowck/src/nll.rs
@@ -389,8 +389,9 @@ pub(super) fn dump_annotation<'a, 'tcx>(
     // viewing the intraprocedural state, the -Zdump-mir output is
     // better.
 
+    let def_span = tcx.def_span(body.source.def_id());
     let mut err = if let Some(closure_region_requirements) = closure_region_requirements {
-        let mut err = tcx.sess.diagnostic().span_note_diag(body.span, "external requirements");
+        let mut err = tcx.sess.diagnostic().span_note_diag(def_span, "external requirements");
 
         regioncx.annotate(tcx, &mut err);
 
@@ -409,7 +410,7 @@ pub(super) fn dump_annotation<'a, 'tcx>(
 
         err
     } else {
-        let mut err = tcx.sess.diagnostic().span_note_diag(body.span, "no external requirements");
+        let mut err = tcx.sess.diagnostic().span_note_diag(def_span, "no external requirements");
         regioncx.annotate(tcx, &mut err);
 
         err
diff --git a/compiler/rustc_borrowck/src/places_conflict.rs b/compiler/rustc_borrowck/src/places_conflict.rs
index 6e5a96bee97e..0e71efd6f8d3 100644
--- a/compiler/rustc_borrowck/src/places_conflict.rs
+++ b/compiler/rustc_borrowck/src/places_conflict.rs
@@ -250,6 +250,7 @@ fn place_components_conflict<'tcx>(
                 | (ProjectionElem::Index { .. }, _, _)
                 | (ProjectionElem::ConstantIndex { .. }, _, _)
                 | (ProjectionElem::Subslice { .. }, _, _)
+                | (ProjectionElem::OpaqueCast { .. }, _, _)
                 | (ProjectionElem::Downcast { .. }, _, _) => {
                     // Recursive case. This can still be disjoint on a
                     // further iteration if this a shallow access and
@@ -317,6 +318,17 @@ fn place_projection_conflict<'tcx>(
             debug!("place_element_conflict: DISJOINT-OR-EQ-DEREF");
             Overlap::EqualOrDisjoint
         }
+        (ProjectionElem::OpaqueCast(v1), ProjectionElem::OpaqueCast(v2)) => {
+            if v1 == v2 {
+                // same type - recur.
+                debug!("place_element_conflict: DISJOINT-OR-EQ-OPAQUE");
+                Overlap::EqualOrDisjoint
+            } else {
+                // Different types. Disjoint!
+                debug!("place_element_conflict: DISJOINT-OPAQUE");
+                Overlap::Disjoint
+            }
+        }
         (ProjectionElem::Field(f1, _), ProjectionElem::Field(f2, _)) => {
             if f1 == f2 {
                 // same field (e.g., `a.y` vs. `a.y`) - recur.
@@ -520,6 +532,7 @@ fn place_projection_conflict<'tcx>(
             | ProjectionElem::Field(..)
             | ProjectionElem::Index(..)
             | ProjectionElem::ConstantIndex { .. }
+            | ProjectionElem::OpaqueCast { .. }
             | ProjectionElem::Subslice { .. }
             | ProjectionElem::Downcast(..),
             _,
diff --git a/compiler/rustc_borrowck/src/prefixes.rs b/compiler/rustc_borrowck/src/prefixes.rs
index bdf2becb7112..2b50cbac9a02 100644
--- a/compiler/rustc_borrowck/src/prefixes.rs
+++ b/compiler/rustc_borrowck/src/prefixes.rs
@@ -81,6 +81,7 @@ impl<'cx, 'tcx> Iterator for Prefixes<'cx, 'tcx> {
                         }
                         ProjectionElem::Downcast(..)
                         | ProjectionElem::Subslice { .. }
+                        | ProjectionElem::OpaqueCast { .. }
                         | ProjectionElem::ConstantIndex { .. }
                         | ProjectionElem::Index(_) => {
                             cursor = cursor_base;
diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index f5bd5cd3beae..244e6e3422d8 100644
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -135,7 +135,6 @@ pub struct RegionInferenceContext<'tcx> {
 /// adds a new lower bound to the SCC it is analyzing: so you wind up
 /// with `'R: 'O` where `'R` is the pick-region and `'O` is the
 /// minimal viable option.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
 pub(crate) struct AppliedMemberConstraint {
     /// The SCC that was affected. (The "member region".)
     ///
@@ -246,6 +245,11 @@ enum Trace<'tcx> {
     NotVisited,
 }
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub enum ExtraConstraintInfo {
+    PlaceholderFromPredicate(Span),
+}
+
 impl<'tcx> RegionInferenceContext<'tcx> {
     /// Creates a new region inference context with a total of
     /// `num_region_variables` valid inference variables; the first N
@@ -591,13 +595,12 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // constraints were too strong, and if so, emit or propagate those errors.
         if infcx.tcx.sess.opts.unstable_opts.polonius {
             self.check_polonius_subset_errors(
-                body,
                 outlives_requirements.as_mut(),
                 &mut errors_buffer,
                 polonius_output.expect("Polonius output is unavailable despite `-Z polonius`"),
             );
         } else {
-            self.check_universal_regions(body, outlives_requirements.as_mut(), &mut errors_buffer);
+            self.check_universal_regions(outlives_requirements.as_mut(), &mut errors_buffer);
         }
 
         if errors_buffer.is_empty() {
@@ -1139,7 +1142,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ///   include the CFG anyhow.
     /// - For each `end('x)` element in `'r`, compute the mutual LUB, yielding
     ///   a result `'y`.
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "debug", ret)]
     pub(crate) fn universal_upper_bound(&self, r: RegionVid) -> RegionVid {
         debug!(r = %self.region_value_str(r));
 
@@ -1151,8 +1154,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             lub = self.universal_region_relations.postdom_upper_bound(lub, ur);
         }
 
-        debug!(?lub);
-
         lub
     }
 
@@ -1333,15 +1334,15 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     // Evaluate whether `sup_region: sub_region`.
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "debug", ret)]
     fn eval_outlives(&self, sup_region: RegionVid, sub_region: RegionVid) -> bool {
         debug!(
-            "eval_outlives: sup_region's value = {:?} universal={:?}",
+            "sup_region's value = {:?} universal={:?}",
             self.region_value_str(sup_region),
             self.universal_regions.is_universal_region(sup_region),
         );
         debug!(
-            "eval_outlives: sub_region's value = {:?} universal={:?}",
+            "sub_region's value = {:?} universal={:?}",
             self.region_value_str(sub_region),
             self.universal_regions.is_universal_region(sub_region),
         );
@@ -1354,7 +1355,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // true if `'sup` outlives static.
         if !self.universe_compatible(sub_region_scc, sup_region_scc) {
             debug!(
-                "eval_outlives: sub universe `{sub_region_scc:?}` is not nameable \
+                "sub universe `{sub_region_scc:?}` is not nameable \
                 by super `{sup_region_scc:?}`, promoting to static",
             );
 
@@ -1375,9 +1376,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             });
 
         if !universal_outlives {
-            debug!(
-                "eval_outlives: returning false because sub region contains a universal region not present in super"
-            );
+            debug!("sub region contains a universal region not present in super");
             return false;
         }
 
@@ -1386,15 +1385,13 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
         if self.universal_regions.is_universal_region(sup_region) {
             // Micro-opt: universal regions contain all points.
-            debug!(
-                "eval_outlives: returning true because super is universal and hence contains all points"
-            );
+            debug!("super is universal and hence contains all points");
             return true;
         }
 
-        let result = self.scc_values.contains_points(sup_region_scc, sub_region_scc);
-        debug!("returning {} because of comparison between points in sup/sub", result);
-        result
+        debug!("comparison between points in sup/sub");
+
+        self.scc_values.contains_points(sup_region_scc, sub_region_scc)
     }
 
     /// Once regions have been propagated, this method is used to see
@@ -1416,7 +1413,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// report them as errors.
     fn check_universal_regions(
         &self,
-        body: &Body<'tcx>,
         mut propagated_outlives_requirements: Option<&mut Vec<ClosureOutlivesRequirement<'tcx>>>,
         errors_buffer: &mut RegionErrors<'tcx>,
     ) {
@@ -1427,7 +1423,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                     // they did not grow too large, accumulating any requirements
                     // for our caller into the `outlives_requirements` vector.
                     self.check_universal_region(
-                        body,
                         fr,
                         &mut propagated_outlives_requirements,
                         errors_buffer,
@@ -1468,7 +1463,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// report them as errors.
     fn check_polonius_subset_errors(
         &self,
-        body: &Body<'tcx>,
         mut propagated_outlives_requirements: Option<&mut Vec<ClosureOutlivesRequirement<'tcx>>>,
         errors_buffer: &mut RegionErrors<'tcx>,
         polonius_output: Rc<PoloniusOutput>,
@@ -1515,7 +1509,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             let propagated = self.try_propagate_universal_region_error(
                 *longer_fr,
                 *shorter_fr,
-                body,
                 &mut propagated_outlives_requirements,
             );
             if propagated == RegionRelationCheckResult::Error {
@@ -1555,13 +1548,9 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ///
     /// Things that are to be propagated are accumulated into the
     /// `outlives_requirements` vector.
-    #[instrument(
-        skip(self, body, propagated_outlives_requirements, errors_buffer),
-        level = "debug"
-    )]
+    #[instrument(skip(self, propagated_outlives_requirements, errors_buffer), level = "debug")]
     fn check_universal_region(
         &self,
-        body: &Body<'tcx>,
         longer_fr: RegionVid,
         propagated_outlives_requirements: &mut Option<&mut Vec<ClosureOutlivesRequirement<'tcx>>>,
         errors_buffer: &mut RegionErrors<'tcx>,
@@ -1584,7 +1573,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             if let RegionRelationCheckResult::Error = self.check_universal_region_relation(
                 longer_fr,
                 representative,
-                body,
                 propagated_outlives_requirements,
             ) {
                 errors_buffer.push(RegionErrorKind::RegionError {
@@ -1604,7 +1592,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             if let RegionRelationCheckResult::Error = self.check_universal_region_relation(
                 longer_fr,
                 shorter_fr,
-                body,
                 propagated_outlives_requirements,
             ) {
                 // We only report the first region error. Subsequent errors are hidden so as
@@ -1629,7 +1616,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         &self,
         longer_fr: RegionVid,
         shorter_fr: RegionVid,
-        body: &Body<'tcx>,
         propagated_outlives_requirements: &mut Option<&mut Vec<ClosureOutlivesRequirement<'tcx>>>,
     ) -> RegionRelationCheckResult {
         // If it is known that `fr: o`, carry on.
@@ -1645,7 +1631,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             self.try_propagate_universal_region_error(
                 longer_fr,
                 shorter_fr,
-                body,
                 propagated_outlives_requirements,
             )
         }
@@ -1657,7 +1642,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         &self,
         longer_fr: RegionVid,
         shorter_fr: RegionVid,
-        body: &Body<'tcx>,
         propagated_outlives_requirements: &mut Option<&mut Vec<ClosureOutlivesRequirement<'tcx>>>,
     ) -> RegionRelationCheckResult {
         if let Some(propagated_outlives_requirements) = propagated_outlives_requirements {
@@ -1669,7 +1653,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 debug!("try_propagate_universal_region_error: fr_minus={:?}", fr_minus);
 
                 let blame_span_category = self.find_outlives_blame_span(
-                    body,
                     longer_fr,
                     NllRegionVariableOrigin::FreeRegion,
                     shorter_fr,
@@ -1823,50 +1806,26 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
     pub(crate) fn retrieve_closure_constraint_info(
         &self,
-        _body: &Body<'tcx>,
-        constraint: &OutlivesConstraint<'tcx>,
-    ) -> BlameConstraint<'tcx> {
-        let loc = match constraint.locations {
-            Locations::All(span) => {
-                return BlameConstraint {
-                    category: constraint.category,
-                    from_closure: false,
-                    cause: ObligationCause::dummy_with_span(span),
-                    variance_info: constraint.variance_info,
-                };
+        constraint: OutlivesConstraint<'tcx>,
+    ) -> Option<(ConstraintCategory<'tcx>, Span)> {
+        match constraint.locations {
+            Locations::All(_) => None,
+            Locations::Single(loc) => {
+                self.closure_bounds_mapping[&loc].get(&(constraint.sup, constraint.sub)).copied()
             }
-            Locations::Single(loc) => loc,
-        };
-
-        let opt_span_category =
-            self.closure_bounds_mapping[&loc].get(&(constraint.sup, constraint.sub));
-        opt_span_category
-            .map(|&(category, span)| BlameConstraint {
-                category,
-                from_closure: true,
-                cause: ObligationCause::dummy_with_span(span),
-                variance_info: constraint.variance_info,
-            })
-            .unwrap_or(BlameConstraint {
-                category: constraint.category,
-                from_closure: false,
-                cause: ObligationCause::dummy_with_span(constraint.span),
-                variance_info: constraint.variance_info,
-            })
+        }
     }
 
     /// Finds a good `ObligationCause` to blame for the fact that `fr1` outlives `fr2`.
     pub(crate) fn find_outlives_blame_span(
         &self,
-        body: &Body<'tcx>,
         fr1: RegionVid,
         fr1_origin: NllRegionVariableOrigin,
         fr2: RegionVid,
     ) -> (ConstraintCategory<'tcx>, ObligationCause<'tcx>) {
-        let BlameConstraint { category, cause, .. } =
-            self.best_blame_constraint(body, fr1, fr1_origin, |r| {
-                self.provides_universal_region(r, fr1, fr2)
-            });
+        let BlameConstraint { category, cause, .. } = self
+            .best_blame_constraint(fr1, fr1_origin, |r| self.provides_universal_region(r, fr1, fr2))
+            .0;
         (category, cause)
     }
 
@@ -1971,7 +1930,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     /// Finds some region R such that `fr1: R` and `R` is live at `elem`.
-    #[instrument(skip(self), level = "trace")]
+    #[instrument(skip(self), level = "trace", ret)]
     pub(crate) fn find_sub_region_live_at(&self, fr1: RegionVid, elem: Location) -> RegionVid {
         trace!(scc = ?self.constraint_sccs.scc(fr1));
         trace!(universe = ?self.scc_universes[self.constraint_sccs.scc(fr1)]);
@@ -2052,11 +2011,10 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     #[instrument(level = "debug", skip(self, target_test))]
     pub(crate) fn best_blame_constraint(
         &self,
-        body: &Body<'tcx>,
         from_region: RegionVid,
         from_region_origin: NllRegionVariableOrigin,
         target_test: impl Fn(RegionVid) -> bool,
-    ) -> BlameConstraint<'tcx> {
+    ) -> (BlameConstraint<'tcx>, Vec<ExtraConstraintInfo>) {
         // Find all paths
         let (path, target_region) =
             self.find_constraint_paths_between_regions(from_region, target_test).unwrap();
@@ -2072,6 +2030,18 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 .collect::<Vec<_>>()
         );
 
+        let mut extra_info = vec![];
+        for constraint in path.iter() {
+            let outlived = constraint.sub;
+            let Some(origin) = self.var_infos.get(outlived) else { continue; };
+            let RegionVariableOrigin::Nll(NllRegionVariableOrigin::Placeholder(p)) = origin.origin else { continue; };
+            debug!(?constraint, ?p);
+            let ConstraintCategory::Predicate(span) = constraint.category else { continue; };
+            extra_info.push(ExtraConstraintInfo::PlaceholderFromPredicate(span));
+            // We only want to point to one
+            break;
+        }
+
         // We try to avoid reporting a `ConstraintCategory::Predicate` as our best constraint.
         // Instead, we use it to produce an improved `ObligationCauseCode`.
         // FIXME - determine what we should do if we encounter multiple `ConstraintCategory::Predicate`
@@ -2097,19 +2067,29 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let mut categorized_path: Vec<BlameConstraint<'tcx>> = path
             .iter()
             .map(|constraint| {
-                if constraint.category == ConstraintCategory::ClosureBounds {
-                    self.retrieve_closure_constraint_info(body, &constraint)
-                } else {
-                    BlameConstraint {
-                        category: constraint.category,
-                        from_closure: false,
-                        cause: ObligationCause::new(
-                            constraint.span,
-                            CRATE_HIR_ID,
-                            cause_code.clone(),
-                        ),
-                        variance_info: constraint.variance_info,
-                    }
+                let (category, span, from_closure, cause_code) =
+                    if constraint.category == ConstraintCategory::ClosureBounds {
+                        if let Some((category, span)) =
+                            self.retrieve_closure_constraint_info(*constraint)
+                        {
+                            (category, span, true, ObligationCauseCode::MiscObligation)
+                        } else {
+                            (
+                                constraint.category,
+                                constraint.span,
+                                false,
+                                ObligationCauseCode::MiscObligation,
+                            )
+                        }
+                    } else {
+                        (constraint.category, constraint.span, false, cause_code.clone())
+                    };
+                BlameConstraint {
+                    category,
+                    from_closure,
+                    cause: ObligationCause::new(span, CRATE_HIR_ID, cause_code),
+                    variance_info: constraint.variance_info,
+                    outlives_constraint: *constraint,
                 }
             })
             .collect();
@@ -2211,7 +2191,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let best_choice =
             if blame_source { range.rev().find(find_region) } else { range.find(find_region) };
 
-        debug!(?best_choice, ?blame_source);
+        debug!(?best_choice, ?blame_source, ?extra_info);
 
         if let Some(i) = best_choice {
             if let Some(next) = categorized_path.get(i + 1) {
@@ -2220,7 +2200,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 {
                     // The return expression is being influenced by the return type being
                     // impl Trait, point at the return type and not the return expr.
-                    return next.clone();
+                    return (next.clone(), extra_info);
                 }
             }
 
@@ -2240,7 +2220,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 }
             }
 
-            return categorized_path[i].clone();
+            return (categorized_path[i].clone(), extra_info);
         }
 
         // If that search fails, that is.. unusual. Maybe everything
@@ -2250,7 +2230,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         categorized_path.sort_by(|p0, p1| p0.category.cmp(&p1.category));
         debug!("sorted_path={:#?}", categorized_path);
 
-        categorized_path.remove(0)
+        (categorized_path.remove(0), extra_info)
     }
 
     pub(crate) fn universe_info(&self, universe: ty::UniverseIndex) -> UniverseInfo<'tcx> {
@@ -2332,7 +2312,13 @@ impl<'tcx> ClosureRegionRequirementsExt<'tcx> for ClosureRegionRequirements<'tcx
                              outlives_requirement={:?}",
                             region, outlived_region, outlives_requirement,
                         );
-                        ty::Binder::dummy(ty::OutlivesPredicate(region.into(), outlived_region))
+                        (
+                            ty::Binder::dummy(ty::OutlivesPredicate(
+                                region.into(),
+                                outlived_region,
+                            )),
+                            ConstraintCategory::BoringNoLocation,
+                        )
                     }
 
                     ClosureOutlivesSubject::Ty(ty) => {
@@ -2342,7 +2328,10 @@ impl<'tcx> ClosureRegionRequirementsExt<'tcx> for ClosureRegionRequirements<'tcx
                              outlives_requirement={:?}",
                             ty, outlived_region, outlives_requirement,
                         );
-                        ty::Binder::dummy(ty::OutlivesPredicate(ty.into(), outlived_region))
+                        (
+                            ty::Binder::dummy(ty::OutlivesPredicate(ty.into(), outlived_region)),
+                            ConstraintCategory::BoringNoLocation,
+                        )
                     }
                 }
             })
@@ -2356,4 +2345,5 @@ pub struct BlameConstraint<'tcx> {
     pub from_closure: bool,
     pub cause: ObligationCause<'tcx>,
     pub variance_info: ty::VarianceDiagInfo<'tcx>,
+    pub outlives_constraint: OutlivesConstraint<'tcx>,
 }
diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
index 127cb4e40837..9d088642f777 100644
--- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
@@ -60,7 +60,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// Calling `universal_upper_bound` for such a region gives `fr_fn_body`,
     /// which has no `external_name` in which case we use `'empty` as the
     /// region to pass to `infer_opaque_definition_from_instantiation`.
-    #[instrument(level = "debug", skip(self, infcx))]
+    #[instrument(level = "debug", skip(self, infcx), ret)]
     pub(crate) fn infer_opaque_types(
         &self,
         infcx: &InferCtxt<'_, 'tcx>,
@@ -109,7 +109,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                         .iter()
                         .find(|ur_vid| self.eval_equal(vid, **ur_vid))
                         .and_then(|ur_vid| self.definitions[*ur_vid].external_name)
-                        .unwrap_or(infcx.tcx.lifetimes.re_root_empty),
+                        .unwrap_or(infcx.tcx.lifetimes.re_erased),
                     _ => region,
                 });
 
@@ -433,7 +433,7 @@ struct ReverseMapper<'tcx> {
 
     key: ty::OpaqueTypeKey<'tcx>,
     map: FxHashMap<GenericArg<'tcx>, GenericArg<'tcx>>,
-    map_missing_regions_to_empty: bool,
+    do_not_error: bool,
 
     /// initially `Some`, set to `None` once error has been reported
     hidden_ty: Option<Ty<'tcx>>,
@@ -450,29 +450,19 @@ impl<'tcx> ReverseMapper<'tcx> {
         hidden_ty: Ty<'tcx>,
         span: Span,
     ) -> Self {
-        Self {
-            tcx,
-            key,
-            map,
-            map_missing_regions_to_empty: false,
-            hidden_ty: Some(hidden_ty),
-            span,
-        }
+        Self { tcx, key, map, do_not_error: false, hidden_ty: Some(hidden_ty), span }
     }
 
-    fn fold_kind_mapping_missing_regions_to_empty(
-        &mut self,
-        kind: GenericArg<'tcx>,
-    ) -> GenericArg<'tcx> {
-        assert!(!self.map_missing_regions_to_empty);
-        self.map_missing_regions_to_empty = true;
+    fn fold_kind_no_missing_regions_error(&mut self, kind: GenericArg<'tcx>) -> GenericArg<'tcx> {
+        assert!(!self.do_not_error);
+        self.do_not_error = true;
         let kind = kind.fold_with(self);
-        self.map_missing_regions_to_empty = false;
+        self.do_not_error = false;
         kind
     }
 
     fn fold_kind_normally(&mut self, kind: GenericArg<'tcx>) -> GenericArg<'tcx> {
-        assert!(!self.map_missing_regions_to_empty);
+        assert!(!self.do_not_error);
         kind.fold_with(self)
     }
 }
@@ -496,9 +486,9 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
             ty::ReErased => return r,
 
             // The regions that we expect from borrow checking.
-            ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReEmpty(ty::UniverseIndex::ROOT) => {}
+            ty::ReEarlyBound(_) | ty::ReFree(_) => {}
 
-            ty::ReEmpty(_) | ty::RePlaceholder(_) | ty::ReVar(_) => {
+            ty::RePlaceholder(_) | ty::ReVar(_) => {
                 // All of the regions in the type should either have been
                 // erased by writeback, or mapped back to named regions by
                 // borrow checking.
@@ -510,7 +500,7 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
         match self.map.get(&r.into()).map(|k| k.unpack()) {
             Some(GenericArgKind::Lifetime(r1)) => r1,
             Some(u) => panic!("region mapped to unexpected kind: {:?}", u),
-            None if self.map_missing_regions_to_empty => self.tcx.lifetimes.re_root_empty,
+            None if self.do_not_error => self.tcx.lifetimes.re_static,
             None if generics.parent.is_some() => {
                 if let Some(hidden_ty) = self.hidden_ty.take() {
                     unexpected_hidden_region_diagnostic(
@@ -522,7 +512,7 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
                     )
                     .emit();
                 }
-                self.tcx.lifetimes.re_root_empty
+                self.tcx.lifetimes.re_static
             }
             None => {
                 self.tcx
@@ -574,7 +564,7 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
                 let substs = self.tcx.mk_substs(substs.iter().enumerate().map(|(index, kind)| {
                     if index < generics.parent_count {
                         // Accommodate missing regions in the parent kinds...
-                        self.fold_kind_mapping_missing_regions_to_empty(kind)
+                        self.fold_kind_no_missing_regions_error(kind)
                     } else {
                         // ...but not elsewhere.
                         self.fold_kind_normally(kind)
@@ -589,7 +579,7 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
                 let substs = self.tcx.mk_substs(substs.iter().enumerate().map(|(index, kind)| {
                     if index < generics.parent_count {
                         // Accommodate missing regions in the parent kinds...
-                        self.fold_kind_mapping_missing_regions_to_empty(kind)
+                        self.fold_kind_no_missing_regions_error(kind)
                     } else {
                         // ...but not elsewhere.
                         self.fold_kind_normally(kind)
diff --git a/compiler/rustc_borrowck/src/renumber.rs b/compiler/rustc_borrowck/src/renumber.rs
index 7a8ce621c5d0..63b2088f7fc0 100644
--- a/compiler/rustc_borrowck/src/renumber.rs
+++ b/compiler/rustc_borrowck/src/renumber.rs
@@ -2,6 +2,7 @@ use rustc_index::vec::IndexVec;
 use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin};
 use rustc_middle::mir::visit::{MutVisitor, TyContext};
 use rustc_middle::mir::{Body, Location, Promoted};
+use rustc_middle::mir::{Constant, ConstantKind};
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
 
@@ -37,6 +38,21 @@ where
     })
 }
 
+// FIXME(valtrees): This function is necessary because `fold_regions`
+// panics for mir constants in the visitor.
+//
+// Once `visit_mir_constant` is removed we can also remove this function
+// and just use `renumber_regions`.
+fn renumber_regions_in_mir_constant<'tcx>(
+    infcx: &InferCtxt<'_, 'tcx>,
+    value: ConstantKind<'tcx>,
+) -> ConstantKind<'tcx> {
+    infcx.tcx.super_fold_regions(value, |_region, _depth| {
+        let origin = NllRegionVariableOrigin::Existential { from_forall: false };
+        infcx.next_nll_region_var(origin)
+    })
+}
+
 struct NllVisitor<'a, 'tcx> {
     infcx: &'a InferCtxt<'a, 'tcx>,
 }
@@ -48,6 +64,13 @@ impl<'a, 'tcx> NllVisitor<'a, 'tcx> {
     {
         renumber_regions(self.infcx, value)
     }
+
+    fn renumber_regions_in_mir_constant(
+        &mut self,
+        value: ConstantKind<'tcx>,
+    ) -> ConstantKind<'tcx> {
+        renumber_regions_in_mir_constant(self.infcx, value)
+    }
 }
 
 impl<'a, 'tcx> MutVisitor<'tcx> for NllVisitor<'a, 'tcx> {
@@ -77,7 +100,10 @@ impl<'a, 'tcx> MutVisitor<'tcx> for NllVisitor<'a, 'tcx> {
         debug!(?region);
     }
 
-    fn visit_const(&mut self, constant: &mut ty::Const<'tcx>, _location: Location) {
-        *constant = self.renumber_regions(*constant);
+    #[instrument(skip(self), level = "debug")]
+    fn visit_constant(&mut self, constant: &mut Constant<'tcx>, _location: Location) {
+        let literal = constant.literal;
+        constant.literal = self.renumber_regions_in_mir_constant(literal);
+        debug!("constant: {:#?}", constant);
     }
 }
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index 5d750c6ca8c7..9f19453a1a65 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -1,11 +1,11 @@
 use rustc_errors::{IntoDiagnosticArg, MultiSpan};
-use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::Ty;
 use rustc_span::Span;
 
 use crate::diagnostics::RegionName;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::move_unsized, code = "E0161")]
 pub(crate) struct MoveUnsized<'tcx> {
     pub ty: Ty<'tcx>,
@@ -14,7 +14,7 @@ pub(crate) struct MoveUnsized<'tcx> {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::higher_ranked_lifetime_error)]
 pub(crate) struct HigherRankedLifetimeError {
     #[subdiagnostic]
@@ -23,7 +23,7 @@ pub(crate) struct HigherRankedLifetimeError {
     pub span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum HigherRankedErrorCause {
     #[note(borrowck::could_not_prove)]
     CouldNotProve { predicate: String },
@@ -31,14 +31,14 @@ pub(crate) enum HigherRankedErrorCause {
     CouldNotNormalize { value: String },
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::higher_ranked_subtype_error)]
 pub(crate) struct HigherRankedSubtypeError {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::generic_does_not_live_long_enough)]
 pub(crate) struct GenericDoesNotLiveLongEnough {
     pub kind: String,
@@ -53,7 +53,7 @@ pub(crate) struct VarNeedNotMut {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::const_not_used_in_type_alias)]
 pub(crate) struct ConstNotUsedTraitAlias {
     pub ct: String,
@@ -61,7 +61,7 @@ pub(crate) struct ConstNotUsedTraitAlias {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::var_cannot_escape_closure)]
 #[note]
 #[note(borrowck::cannot_escape)]
@@ -72,7 +72,7 @@ pub(crate) struct FnMutError {
     pub ty_err: FnMutReturnTypeErr,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum VarHereDenote {
     #[label(borrowck::var_here_captured)]
     Captured {
@@ -91,7 +91,7 @@ pub(crate) enum VarHereDenote {
     },
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum FnMutReturnTypeErr {
     #[label(borrowck::returned_closure_escaped)]
     ReturnClosure {
@@ -110,14 +110,14 @@ pub(crate) enum FnMutReturnTypeErr {
     },
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(borrowck::lifetime_constraints_error)]
 pub(crate) struct LifetimeOutliveErr {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum LifetimeReturnCategoryErr<'a> {
     #[label(borrowck::returned_lifetime_wrong)]
     WrongReturn {
@@ -149,7 +149,7 @@ impl IntoDiagnosticArg for RegionName {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum RequireStaticErr {
     #[note(borrowck::used_impl_require_static)]
     UsedImpl {
diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs
index 29195b3922fc..9271a2f4dc71 100644
--- a/compiler/rustc_borrowck/src/type_check/canonical.rs
+++ b/compiler/rustc_borrowck/src/type_check/canonical.rs
@@ -25,7 +25,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     /// constraints should occur within this method so that those
     /// constraints can be properly localized!**
     #[instrument(skip(self, op), level = "trace")]
-    pub(super) fn fully_perform_op<R, Op>(
+    pub(super) fn fully_perform_op<R: fmt::Debug, Op>(
         &mut self,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
@@ -39,6 +39,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
         let TypeOpOutput { output, constraints, error_info } = op.fully_perform(self.infcx)?;
 
+        debug!(?output, ?constraints);
+
         if let Some(data) = constraints {
             self.push_region_constraints(locations, category, data);
         }
@@ -102,6 +104,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         );
     }
 
+    #[instrument(level = "debug", skip(self))]
     pub(super) fn normalize_and_prove_instantiated_predicates(
         &mut self,
         // Keep this parameter for now, in case we start using
@@ -116,8 +119,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             .zip(instantiated_predicates.spans.into_iter())
         {
             debug!(?predicate);
-            let predicate = self.normalize(predicate, locations);
-            self.prove_predicate(predicate, locations, ConstraintCategory::Predicate(span));
+            let category = ConstraintCategory::Predicate(span);
+            let predicate = self.normalize_with_category(predicate, locations, category);
+            self.prove_predicate(predicate, locations, category);
         }
     }
 
@@ -153,15 +157,27 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         })
     }
 
-    #[instrument(skip(self), level = "debug")]
     pub(super) fn normalize<T>(&mut self, value: T, location: impl NormalizeLocation) -> T
+    where
+        T: type_op::normalize::Normalizable<'tcx> + fmt::Display + Copy + 'tcx,
+    {
+        self.normalize_with_category(value, location, ConstraintCategory::Boring)
+    }
+
+    #[instrument(skip(self), level = "debug")]
+    pub(super) fn normalize_with_category<T>(
+        &mut self,
+        value: T,
+        location: impl NormalizeLocation,
+        category: ConstraintCategory<'tcx>,
+    ) -> T
     where
         T: type_op::normalize::Normalizable<'tcx> + fmt::Display + Copy + 'tcx,
     {
         let param_env = self.param_env;
         self.fully_perform_op(
             location.to_locations(),
-            ConstraintCategory::Boring,
+            category,
             param_env.and(type_op::normalize::Normalize::new(value)),
         )
         .unwrap_or_else(|NoSolution| {
diff --git a/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs b/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
index 9fab7ad914a8..71eae0583cb4 100644
--- a/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
+++ b/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
@@ -86,7 +86,7 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
         }
     }
 
-    pub(super) fn convert(&mut self, query_constraint: &QueryOutlivesConstraint<'tcx>) {
+    fn convert(&mut self, query_constraint: &QueryOutlivesConstraint<'tcx>) {
         debug!("generate: constraints at: {:#?}", self.locations);
 
         // Extract out various useful fields we'll need below.
@@ -98,15 +98,18 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
         // region constraints like `for<'a> 'a: 'b`. At some point
         // when we move to universes, we will, and this assertion
         // will start to fail.
-        let ty::OutlivesPredicate(k1, r2) = query_constraint.no_bound_vars().unwrap_or_else(|| {
-            bug!("query_constraint {:?} contained bound vars", query_constraint,);
-        });
+        let ty::OutlivesPredicate(k1, r2) =
+            query_constraint.0.no_bound_vars().unwrap_or_else(|| {
+                bug!("query_constraint {:?} contained bound vars", query_constraint,);
+            });
+
+        let constraint_category = query_constraint.1;
 
         match k1.unpack() {
             GenericArgKind::Lifetime(r1) => {
                 let r1_vid = self.to_region_vid(r1);
                 let r2_vid = self.to_region_vid(r2);
-                self.add_outlives(r1_vid, r2_vid);
+                self.add_outlives(r1_vid, r2_vid, constraint_category);
             }
 
             GenericArgKind::Type(t1) => {
@@ -121,7 +124,7 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
                     Some(implicit_region_bound),
                     param_env,
                 )
-                .type_must_outlive(origin, t1, r2);
+                .type_must_outlive(origin, t1, r2, constraint_category);
             }
 
             GenericArgKind::Const(_) => {
@@ -168,10 +171,19 @@ impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
         }
     }
 
-    fn add_outlives(&mut self, sup: ty::RegionVid, sub: ty::RegionVid) {
+    fn add_outlives(
+        &mut self,
+        sup: ty::RegionVid,
+        sub: ty::RegionVid,
+        category: ConstraintCategory<'tcx>,
+    ) {
+        let category = match self.category {
+            ConstraintCategory::Boring | ConstraintCategory::BoringNoLocation => category,
+            _ => self.category,
+        };
         self.constraints.outlives_constraints.push(OutlivesConstraint {
             locations: self.locations,
-            category: self.category,
+            category,
             span: self.span,
             sub,
             sup,
@@ -191,10 +203,11 @@ impl<'a, 'b, 'tcx> TypeOutlivesDelegate<'tcx> for &'a mut ConstraintConversion<'
         _origin: SubregionOrigin<'tcx>,
         a: ty::Region<'tcx>,
         b: ty::Region<'tcx>,
+        constraint_category: ConstraintCategory<'tcx>,
     ) {
         let b = self.to_region_vid(b);
         let a = self.to_region_vid(a);
-        self.add_outlives(b, a);
+        self.add_outlives(b, a, constraint_category);
     }
 
     fn push_verify(
diff --git a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
index 7c10047e9dc8..e0140e281ee7 100644
--- a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
+++ b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
@@ -347,13 +347,6 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> {
 
             match outlives_bound {
                 OutlivesBound::RegionSubRegion(r1, r2) => {
-                    // `where Type:` is lowered to `where Type: 'empty` so that
-                    // we check `Type` is well formed, but there's no use for
-                    // this bound here.
-                    if r1.is_empty() {
-                        return;
-                    }
-
                     // The bound says that `r1 <= r2`; we store `r2: r1`.
                     let r1 = self.universal_regions.to_region_vid(r1);
                     let r2 = self.universal_regions.to_region_vid(r2);
@@ -369,6 +362,11 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> {
                     self.region_bound_pairs
                         .insert(ty::OutlivesPredicate(GenericKind::Projection(projection_b), r_a));
                 }
+
+                OutlivesBound::RegionSubOpaque(r_a, def_id, substs) => {
+                    self.region_bound_pairs
+                        .insert(ty::OutlivesPredicate(GenericKind::Opaque(def_id, substs), r_a));
+                }
             }
         }
     }
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index a620c987052b..d03f03696485 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -30,8 +30,9 @@ use rustc_middle::ty::cast::CastTy;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef, UserSubsts};
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{
-    self, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, OpaqueHiddenType,
-    OpaqueTypeKey, RegionVid, ToPredicate, Ty, TyCtxt, UserType, UserTypeAnnotationIndex,
+    self, Binder, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, Dynamic,
+    OpaqueHiddenType, OpaqueTypeKey, RegionVid, ToPredicate, Ty, TyCtxt, UserType,
+    UserTypeAnnotationIndex,
 };
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::{Span, DUMMY_SP};
@@ -311,6 +312,8 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
     }
 
     fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
+        debug!(?constant, ?location, "visit_constant");
+
         self.super_constant(constant, location);
         let ty = self.sanitize_type(constant, constant.literal.ty());
 
@@ -354,11 +357,15 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
             let tcx = self.tcx();
             let maybe_uneval = match constant.literal {
                 ConstantKind::Ty(ct) => match ct.kind() {
-                    ty::ConstKind::Unevaluated(uv) => Some(uv),
+                    ty::ConstKind::Unevaluated(_) => {
+                        bug!("should not encounter unevaluated ConstantKind::Ty here, got {:?}", ct)
+                    }
                     _ => None,
                 },
+                ConstantKind::Unevaluated(uv, _) => Some(uv),
                 _ => None,
             };
+
             if let Some(uv) = maybe_uneval {
                 if let Some(promoted) = uv.promoted {
                     let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
@@ -421,12 +428,18 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
             }
 
             if let ty::FnDef(def_id, substs) = *constant.literal.ty().kind() {
+                // const_trait_impl: use a non-const param env when checking that a FnDef type is well formed.
+                // this is because the well-formedness of the function does not need to be proved to have `const`
+                // impls for trait bounds.
                 let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
+                let prev = self.cx.param_env;
+                self.cx.param_env = prev.without_const();
                 self.cx.normalize_and_prove_instantiated_predicates(
                     def_id,
                     instantiated_predicates,
                     locations,
                 );
+                self.cx.param_env = prev;
             }
         }
     }
@@ -757,6 +770,19 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
                 }
                 PlaceTy::from_ty(fty)
             }
+            ProjectionElem::OpaqueCast(ty) => {
+                let ty = self.sanitize_type(place, ty);
+                let ty = self.cx.normalize(ty, location);
+                self.cx
+                    .eq_types(
+                        base.ty,
+                        ty,
+                        location.to_locations(),
+                        ConstraintCategory::TypeAnnotation,
+                    )
+                    .unwrap();
+                PlaceTy::from_ty(ty)
+            }
         }
     }
 
@@ -1163,10 +1189,11 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 tcx,
                 self.param_env,
                 proj,
-                |this, field, ()| {
+                |this, field, _| {
                     let ty = this.field_ty(tcx, field);
                     self.normalize(ty, locations)
                 },
+                |_, _| unreachable!(),
             );
             curr_projected_ty = projected_ty;
         }
@@ -1302,12 +1329,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     );
                 }
             }
-            StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
-                ..
-            }) => span_bug!(
-                stmt.source_info.span,
-                "Unexpected StatementKind::CopyNonOverlapping, should only appear after lowering_intrinsics",
-            ),
+            StatementKind::Intrinsic(box ref kind) => match kind {
+                NonDivergingIntrinsic::Assume(op) => self.check_operand(op, location),
+                NonDivergingIntrinsic::CopyNonOverlapping(..) => span_bug!(
+                    stmt.source_info.span,
+                    "Unexpected NonDivergingIntrinsic::CopyNonOverlapping, should only appear after lowering_intrinsics",
+                ),
+            },
             StatementKind::FakeRead(..)
             | StatementKind::StorageLive(..)
             | StatementKind::StorageDead(..)
@@ -1809,14 +1837,14 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     }
 
     fn check_operand(&mut self, op: &Operand<'tcx>, location: Location) {
+        debug!(?op, ?location, "check_operand");
+
         if let Operand::Constant(constant) = op {
             let maybe_uneval = match constant.literal {
-                ConstantKind::Ty(ct) => match ct.kind() {
-                    ty::ConstKind::Unevaluated(uv) => Some(uv),
-                    _ => None,
-                },
-                _ => None,
+                ConstantKind::Val(..) | ConstantKind::Ty(_) => None,
+                ConstantKind::Unevaluated(uv, _) => Some(uv),
             };
+
             if let Some(uv) = maybe_uneval {
                 if uv.promoted.is_none() {
                     let tcx = self.tcx();
@@ -2008,6 +2036,36 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         );
                     }
 
+                    CastKind::DynStar => {
+                        // get the constraints from the target type (`dyn* Clone`)
+                        //
+                        // apply them to prove that the source type `Foo` implements `Clone` etc
+                        let (existential_predicates, region) = match ty.kind() {
+                            Dynamic(predicates, region, ty::DynStar) => (predicates, region),
+                            _ => panic!("Invalid dyn* cast_ty"),
+                        };
+
+                        let self_ty = op.ty(body, tcx);
+
+                        self.prove_predicates(
+                            existential_predicates
+                                .iter()
+                                .map(|predicate| predicate.with_self_ty(tcx, self_ty)),
+                            location.to_locations(),
+                            ConstraintCategory::Cast,
+                        );
+
+                        let outlives_predicate =
+                            tcx.mk_predicate(Binder::dummy(ty::PredicateKind::TypeOutlives(
+                                ty::OutlivesPredicate(self_ty, *region),
+                            )));
+                        self.prove_predicate(
+                            outlives_predicate,
+                            location.to_locations(),
+                            ConstraintCategory::Cast,
+                        );
+                    }
+
                     CastKind::Pointer(PointerCast::MutToConstPointer) => {
                         let ty::RawPtr(ty::TypeAndMut {
                             ty: ty_from,
@@ -2465,6 +2523,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 }
                 ProjectionElem::Field(..)
                 | ProjectionElem::Downcast(..)
+                | ProjectionElem::OpaqueCast(..)
                 | ProjectionElem::Index(..)
                 | ProjectionElem::ConstantIndex { .. }
                 | ProjectionElem::Subslice { .. } => {
@@ -2559,7 +2618,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 .enumerate()
                 .filter_map(|(idx, constraint)| {
                     let ty::OutlivesPredicate(k1, r2) =
-                        constraint.no_bound_vars().unwrap_or_else(|| {
+                        constraint.0.no_bound_vars().unwrap_or_else(|| {
                             bug!("query_constraint {:?} contained bound vars", constraint,);
                         });
 
diff --git a/compiler/rustc_borrowck/src/universal_regions.rs b/compiler/rustc_borrowck/src/universal_regions.rs
index 2a7713bc4df3..41fba8deb10e 100644
--- a/compiler/rustc_borrowck/src/universal_regions.rs
+++ b/compiler/rustc_borrowck/src/universal_regions.rs
@@ -22,8 +22,8 @@ use rustc_hir::{BodyOwnerKind, HirId};
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin};
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::{self, InlineConstSubsts, InlineConstSubstsParts, RegionVid, Ty, TyCtxt};
+use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use std::iter;
 
 use crate::nll::ToRegionVid;
@@ -54,13 +54,6 @@ pub struct UniversalRegions<'tcx> {
     /// The total number of universal region variables instantiated.
     num_universals: usize,
 
-    /// A special region variable created for the `'empty(U0)` region.
-    /// Note that this is **not** a "universal" region, as it doesn't
-    /// represent a universally bound placeholder or any such thing.
-    /// But we do create it here in this type because it's a useful region
-    /// to have around in a few limited cases.
-    pub root_empty: RegionVid,
-
     /// The "defining" type for this function, with all universal
     /// regions instantiated. For a closure or generator, this is the
     /// closure type, but for a top-level function it's the `FnDef`.
@@ -323,11 +316,7 @@ impl<'tcx> UniversalRegions<'tcx> {
 
     /// See `UniversalRegionIndices::to_region_vid`.
     pub fn to_region_vid(&self, r: ty::Region<'tcx>) -> RegionVid {
-        if let ty::ReEmpty(ty::UniverseIndex::ROOT) = *r {
-            self.root_empty
-        } else {
-            self.indices.to_region_vid(r)
-        }
+        self.indices.to_region_vid(r)
     }
 
     /// As part of the NLL unit tests, you can annotate a function with
@@ -501,16 +490,10 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             _ => None,
         };
 
-        let root_empty = self
-            .infcx
-            .next_nll_region_var(NllRegionVariableOrigin::Existential { from_forall: true })
-            .to_region_vid();
-
         UniversalRegions {
             indices,
             fr_static,
             fr_fn_body,
-            root_empty,
             first_extern_index,
             first_local_index,
             num_universals,
@@ -768,10 +751,9 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'cx, 'tcx> {
         mir_def_id: LocalDefId,
         indices: &mut UniversalRegionIndices<'tcx>,
     ) {
-        debug!("replace_late_bound_regions_with_nll_infer_vars(mir_def_id={:?})", mir_def_id);
         let typeck_root_def_id = self.tcx.typeck_root_def_id(mir_def_id.to_def_id());
         for_each_late_bound_region_defined_on(self.tcx, typeck_root_def_id, |r| {
-            debug!("replace_late_bound_regions_with_nll_infer_vars: r={:?}", r);
+            debug!(?r);
             if !indices.indices.contains_key(&r) {
                 let region_vid = self.next_nll_region_var(FR);
                 debug!(?region_vid);
diff --git a/compiler/rustc_builtin_macros/Cargo.toml b/compiler/rustc_builtin_macros/Cargo.toml
index 8d8e9d9b5ff4..6469d0d7b88a 100644
--- a/compiler/rustc_builtin_macros/Cargo.toml
+++ b/compiler/rustc_builtin_macros/Cargo.toml
@@ -7,20 +7,21 @@ edition = "2021"
 doctest = false
 
 [dependencies]
-rustc_parse_format = { path = "../rustc_parse_format" }
-tracing = "0.1"
+rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
 rustc_attr = { path = "../rustc_attr" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
+rustc_expand = { path = "../rustc_expand" }
 rustc_feature = { path = "../rustc_feature" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
 rustc_macros = { path = "../rustc_macros" }
+rustc_parse_format = { path = "../rustc_parse_format" }
 rustc_parse = { path = "../rustc_parse" }
-rustc_target = { path = "../rustc_target" }
 rustc_session = { path = "../rustc_session" }
-smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
-rustc_ast = { path = "../rustc_ast" }
-rustc_expand = { path = "../rustc_expand" }
 rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
+smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+thin-vec = "0.2.8"
+tracing = "0.1"
diff --git a/compiler/rustc_builtin_macros/src/assert/context.rs b/compiler/rustc_builtin_macros/src/assert/context.rs
index d2ee4249989e..973a8cb85c2b 100644
--- a/compiler/rustc_builtin_macros/src/assert/context.rs
+++ b/compiler/rustc_builtin_macros/src/assert/context.rs
@@ -13,6 +13,7 @@ use rustc_span::{
     symbol::{sym, Ident, Symbol},
     Span,
 };
+use thin_vec::thin_vec;
 
 pub(super) struct Context<'cx, 'a> {
     // An optimization.
@@ -116,11 +117,10 @@ impl<'cx, 'a> Context<'cx, 'a> {
             self.cx.item(
                 self.span,
                 Ident::empty(),
-                vec![self.cx.attribute(attr::mk_list_item(
+                thin_vec![self.cx.attribute(attr::mk_list_item(
                     Ident::new(sym::allow, self.span),
                     vec![attr::mk_nested_word_item(Ident::new(sym::unused_imports, self.span))],
-                ))]
-                .into(),
+                ))],
                 ItemKind::Use(UseTree {
                     prefix: self.cx.path(self.span, self.cx.std_path(&[sym::asserting])),
                     kind: UseTreeKind::Nested(vec![
diff --git a/compiler/rustc_builtin_macros/src/cfg.rs b/compiler/rustc_builtin_macros/src/cfg.rs
index 9046bf130593..46b54eae3849 100644
--- a/compiler/rustc_builtin_macros/src/cfg.rs
+++ b/compiler/rustc_builtin_macros/src/cfg.rs
@@ -8,7 +8,7 @@ use rustc_ast::tokenstream::TokenStream;
 use rustc_attr as attr;
 use rustc_errors::PResult;
 use rustc_expand::base::{self, *};
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 use rustc_span::Span;
 
 pub fn expand_cfg(
@@ -35,7 +35,7 @@ pub fn expand_cfg(
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(builtin_macros::requires_cfg_pattern)]
 struct RequiresCfgPattern {
     #[primary_span]
@@ -43,7 +43,7 @@ struct RequiresCfgPattern {
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(builtin_macros::expected_one_cfg_pattern)]
 struct OneCfgPattern {
     #[primary_span]
diff --git a/compiler/rustc_builtin_macros/src/cfg_eval.rs b/compiler/rustc_builtin_macros/src/cfg_eval.rs
index 89b2c329236d..009f3c783d4c 100644
--- a/compiler/rustc_builtin_macros/src/cfg_eval.rs
+++ b/compiler/rustc_builtin_macros/src/cfg_eval.rs
@@ -7,6 +7,7 @@ use rustc_ast::visit::Visitor;
 use rustc_ast::NodeId;
 use rustc_ast::{mut_visit, visit};
 use rustc_ast::{Attribute, HasAttrs, HasTokens};
+use rustc_errors::PResult;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_expand::config::StripUnconfigured;
 use rustc_expand::configure;
@@ -144,33 +145,34 @@ impl CfgEval<'_, '_> {
         // the location of `#[cfg]` and `#[cfg_attr]` in the token stream. The tokenization
         // process is lossless, so this process is invisible to proc-macros.
 
-        let parse_annotatable_with: fn(&mut Parser<'_>) -> _ = match annotatable {
-            Annotatable::Item(_) => {
-                |parser| Annotatable::Item(parser.parse_item(ForceCollect::Yes).unwrap().unwrap())
-            }
-            Annotatable::TraitItem(_) => |parser| {
-                Annotatable::TraitItem(
-                    parser.parse_trait_item(ForceCollect::Yes).unwrap().unwrap().unwrap(),
-                )
-            },
-            Annotatable::ImplItem(_) => |parser| {
-                Annotatable::ImplItem(
-                    parser.parse_impl_item(ForceCollect::Yes).unwrap().unwrap().unwrap(),
-                )
-            },
-            Annotatable::ForeignItem(_) => |parser| {
-                Annotatable::ForeignItem(
-                    parser.parse_foreign_item(ForceCollect::Yes).unwrap().unwrap().unwrap(),
-                )
-            },
-            Annotatable::Stmt(_) => |parser| {
-                Annotatable::Stmt(P(parser.parse_stmt(ForceCollect::Yes).unwrap().unwrap()))
-            },
-            Annotatable::Expr(_) => {
-                |parser| Annotatable::Expr(parser.parse_expr_force_collect().unwrap())
-            }
-            _ => unreachable!(),
-        };
+        let parse_annotatable_with: for<'a> fn(&mut Parser<'a>) -> PResult<'a, _> =
+            match annotatable {
+                Annotatable::Item(_) => {
+                    |parser| Ok(Annotatable::Item(parser.parse_item(ForceCollect::Yes)?.unwrap()))
+                }
+                Annotatable::TraitItem(_) => |parser| {
+                    Ok(Annotatable::TraitItem(
+                        parser.parse_trait_item(ForceCollect::Yes)?.unwrap().unwrap(),
+                    ))
+                },
+                Annotatable::ImplItem(_) => |parser| {
+                    Ok(Annotatable::ImplItem(
+                        parser.parse_impl_item(ForceCollect::Yes)?.unwrap().unwrap(),
+                    ))
+                },
+                Annotatable::ForeignItem(_) => |parser| {
+                    Ok(Annotatable::ForeignItem(
+                        parser.parse_foreign_item(ForceCollect::Yes)?.unwrap().unwrap(),
+                    ))
+                },
+                Annotatable::Stmt(_) => |parser| {
+                    Ok(Annotatable::Stmt(P(parser.parse_stmt(ForceCollect::Yes)?.unwrap())))
+                },
+                Annotatable::Expr(_) => {
+                    |parser| Ok(Annotatable::Expr(parser.parse_expr_force_collect()?))
+                }
+                _ => unreachable!(),
+            };
 
         // 'Flatten' all nonterminals (i.e. `TokenKind::Interpolated`)
         // to `None`-delimited groups containing the corresponding tokens. This
@@ -188,14 +190,20 @@ impl CfgEval<'_, '_> {
         let orig_tokens = annotatable.to_tokens().flattened();
 
         // Re-parse the tokens, setting the `capture_cfg` flag to save extra information
-        // to the captured `AttrAnnotatedTokenStream` (specifically, we capture
-        // `AttrAnnotatedTokenTree::AttributesData` for all occurrences of `#[cfg]` and `#[cfg_attr]`)
+        // to the captured `AttrTokenStream` (specifically, we capture
+        // `AttrTokenTree::AttributesData` for all occurrences of `#[cfg]` and `#[cfg_attr]`)
         let mut parser =
             rustc_parse::stream_to_parser(&self.cfg.sess.parse_sess, orig_tokens, None);
         parser.capture_cfg = true;
-        annotatable = parse_annotatable_with(&mut parser);
+        match parse_annotatable_with(&mut parser) {
+            Ok(a) => annotatable = a,
+            Err(mut err) => {
+                err.emit();
+                return Some(annotatable);
+            }
+        }
 
-        // Now that we have our re-parsed `AttrAnnotatedTokenStream`, recursively configuring
+        // Now that we have our re-parsed `AttrTokenStream`, recursively configuring
         // our attribute target will correctly the tokens as well.
         flat_map_annotatable(self, annotatable)
     }
diff --git a/compiler/rustc_builtin_macros/src/cmdline_attrs.rs b/compiler/rustc_builtin_macros/src/cmdline_attrs.rs
index 747e48ece704..db05c00d2118 100644
--- a/compiler/rustc_builtin_macros/src/cmdline_attrs.rs
+++ b/compiler/rustc_builtin_macros/src/cmdline_attrs.rs
@@ -28,7 +28,13 @@ pub fn inject(mut krate: ast::Crate, parse_sess: &ParseSess, attrs: &[String]) -
             continue;
         }
 
-        krate.attrs.push(mk_attr(AttrStyle::Inner, path, args, start_span.to(end_span)));
+        krate.attrs.push(mk_attr(
+            &parse_sess.attr_id_generator,
+            AttrStyle::Inner,
+            path,
+            args,
+            start_span.to(end_span),
+        ));
     }
 
     krate
diff --git a/compiler/rustc_builtin_macros/src/derive.rs b/compiler/rustc_builtin_macros/src/derive.rs
index 467ac34ded94..e0fb7affb349 100644
--- a/compiler/rustc_builtin_macros/src/derive.rs
+++ b/compiler/rustc_builtin_macros/src/derive.rs
@@ -32,7 +32,8 @@ impl MultiItemModifier for Expander {
             ecx.resolver.resolve_derives(ecx.current_expansion.id, ecx.force_mode, &|| {
                 let template =
                     AttributeTemplate { list: Some("Trait1, Trait2, ..."), ..Default::default() };
-                let attr = attr::mk_attr_outer(meta_item.clone());
+                let attr =
+                    attr::mk_attr_outer(&sess.parse_sess.attr_id_generator, meta_item.clone());
                 validate_attr::check_builtin_attribute(
                     &sess.parse_sess,
                     &attr,
diff --git a/compiler/rustc_builtin_macros/src/deriving/clone.rs b/compiler/rustc_builtin_macros/src/deriving/clone.rs
index dd7989cf48c3..c7f2d95e72f0 100644
--- a/compiler/rustc_builtin_macros/src/deriving/clone.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/clone.rs
@@ -1,12 +1,12 @@
 use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::path_std;
-
 use rustc_ast::{self as ast, Generics, ItemKind, MetaItem, VariantData};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 pub fn expand_deriving_clone(
     cx: &mut ExtCtxt<'_>,
@@ -68,7 +68,7 @@ pub fn expand_deriving_clone(
     }
 
     let inline = cx.meta_word(span, sym::inline);
-    let attrs = vec![cx.attribute(inline)].into();
+    let attrs = thin_vec![cx.attribute(inline)];
     let trait_def = TraitDef {
         span,
         path: path_std!(clone::Clone),
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
index 9b6d3e5032f9..5b556c5c9b9d 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
@@ -7,6 +7,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 pub fn expand_deriving_eq(
     cx: &mut ExtCtxt<'_>,
@@ -20,7 +21,7 @@ pub fn expand_deriving_eq(
     let hidden = rustc_ast::attr::mk_nested_word_item(Ident::new(sym::hidden, span));
     let doc = rustc_ast::attr::mk_list_item(Ident::new(sym::doc, span), vec![hidden]);
     let no_coverage = cx.meta_word(span, sym::no_coverage);
-    let attrs = vec![cx.attribute(inline), cx.attribute(doc), cx.attribute(no_coverage)].into();
+    let attrs = thin_vec![cx.attribute(inline), cx.attribute(doc), cx.attribute(no_coverage)];
     let trait_def = TraitDef {
         span,
         path: path_std!(cmp::Eq),
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
index 0e17b9517875..726258695581 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
@@ -1,11 +1,11 @@
 use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::path_std;
-
 use rustc_ast::MetaItem;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 pub fn expand_deriving_ord(
     cx: &mut ExtCtxt<'_>,
@@ -15,7 +15,7 @@ pub fn expand_deriving_ord(
     push: &mut dyn FnMut(Annotatable),
 ) {
     let inline = cx.meta_word(span, sym::inline);
-    let attrs = vec![cx.attribute(inline)].into();
+    let attrs = thin_vec![cx.attribute(inline)];
     let trait_def = TraitDef {
         span,
         path: path_std!(cmp::Ord),
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
index ac1325b92a6f..42ee65b570a2 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
@@ -1,12 +1,12 @@
 use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::{path_local, path_std};
-
 use rustc_ast::ptr::P;
 use rustc_ast::{BinOpKind, BorrowKind, Expr, ExprKind, MetaItem, Mutability};
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 pub fn expand_deriving_partial_eq(
     cx: &mut ExtCtxt<'_>,
@@ -68,7 +68,7 @@ pub fn expand_deriving_partial_eq(
     // No need to generate `ne`, the default suffices, and not generating it is
     // faster.
     let inline = cx.meta_word(span, sym::inline);
-    let attrs = vec![cx.attribute(inline)].into();
+    let attrs = thin_vec![cx.attribute(inline)];
     let methods = vec![MethodDef {
         name: sym::eq,
         generics: Bounds::empty(),
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
index 7763e5540178..516892aeda96 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
@@ -1,11 +1,11 @@
 use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::{path_std, pathvec_std};
-
 use rustc_ast::MetaItem;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 pub fn expand_deriving_partial_ord(
     cx: &mut ExtCtxt<'_>,
@@ -19,7 +19,7 @@ pub fn expand_deriving_partial_ord(
         Path(Path::new_(pathvec_std!(option::Option), vec![Box::new(ordering_ty)], PathKind::Std));
 
     let inline = cx.meta_word(span, sym::inline);
-    let attrs = vec![cx.attribute(inline)].into();
+    let attrs = thin_vec![cx.attribute(inline)];
 
     let partial_cmp_def = MethodDef {
         name: sym::partial_cmp,
diff --git a/compiler/rustc_builtin_macros/src/deriving/default.rs b/compiler/rustc_builtin_macros/src/deriving/default.rs
index f316f01ef661..a94c8a996e64 100644
--- a/compiler/rustc_builtin_macros/src/deriving/default.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/default.rs
@@ -1,6 +1,5 @@
 use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
-
 use rustc_ast as ast;
 use rustc_ast::{walk_list, EnumDef, VariantData};
 use rustc_errors::Applicability;
@@ -9,6 +8,7 @@ use rustc_span::symbol::Ident;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::Span;
 use smallvec::SmallVec;
+use thin_vec::thin_vec;
 
 pub fn expand_deriving_default(
     cx: &mut ExtCtxt<'_>,
@@ -20,7 +20,7 @@ pub fn expand_deriving_default(
     item.visit_with(&mut DetectNonVariantDefaultAttr { cx });
 
     let inline = cx.meta_word(span, sym::inline);
-    let attrs = vec![cx.attribute(inline)].into();
+    let attrs = thin_vec![cx.attribute(inline)];
     let trait_def = TraitDef {
         span,
         path: Path::new(vec![kw::Default, sym::Default]),
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index ecaafd0fc265..3cc160adb539 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -162,22 +162,22 @@
 pub use StaticFields::*;
 pub use SubstructureFields::*;
 
-use std::cell::RefCell;
-use std::iter;
-use std::vec;
-
+use crate::deriving;
 use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, EnumDef, Expr, Generics, PatKind};
+use rustc_ast::{
+    self as ast, BindingAnnotation, ByRef, EnumDef, Expr, Generics, Mutability, PatKind,
+};
 use rustc_ast::{GenericArg, GenericParamKind, VariantData};
 use rustc_attr as attr;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::Span;
-
+use std::cell::RefCell;
+use std::iter;
+use std::vec;
+use thin_vec::thin_vec;
 use ty::{Bounds, Path, Ref, Self_, Ty};
 
-use crate::deriving;
-
 pub mod ty;
 
 pub struct TraitDef<'a> {
@@ -715,7 +715,7 @@ impl<'a> TraitDef<'a> {
         let self_type = cx.ty_path(path);
 
         let attr = cx.attribute(cx.meta_word(self.span, sym::automatically_derived));
-        let attrs = vec![attr].into();
+        let attrs = thin_vec![attr];
         let opt_trait_ref = Some(trait_ref);
 
         cx.item(
@@ -1065,9 +1065,9 @@ impl<'a> MethodDef<'a> {
             let mut body = mk_body(cx, selflike_fields);
 
             let struct_path = cx.path(span, vec![Ident::new(kw::SelfUpper, type_ident.span)]);
-            let use_ref_pat = is_packed && !always_copy;
+            let by_ref = ByRef::from(is_packed && !always_copy);
             let patterns =
-                trait_.create_struct_patterns(cx, struct_path, struct_def, &prefixes, use_ref_pat);
+                trait_.create_struct_patterns(cx, struct_path, struct_def, &prefixes, by_ref);
 
             // Do the let-destructuring.
             let mut stmts: Vec<_> = iter::zip(selflike_args, patterns)
@@ -1249,13 +1249,13 @@ impl<'a> MethodDef<'a> {
 
                 let sp = variant.span.with_ctxt(trait_.span.ctxt());
                 let variant_path = cx.path(sp, vec![type_ident, variant.ident]);
-                let use_ref_pat = false; // because enums can't be repr(packed)
+                let by_ref = ByRef::No; // because enums can't be repr(packed)
                 let mut subpats: Vec<_> = trait_.create_struct_patterns(
                     cx,
                     variant_path,
                     &variant.data,
                     &prefixes,
-                    use_ref_pat,
+                    by_ref,
                 );
 
                 // `(VariantK, VariantK, ...)` or just `VariantK`.
@@ -1416,7 +1416,7 @@ impl<'a> TraitDef<'a> {
         struct_path: ast::Path,
         struct_def: &'a VariantData,
         prefixes: &[String],
-        use_ref_pat: bool,
+        by_ref: ByRef,
     ) -> Vec<P<ast::Pat>> {
         prefixes
             .iter()
@@ -1424,17 +1424,19 @@ impl<'a> TraitDef<'a> {
                 let pieces_iter =
                     struct_def.fields().iter().enumerate().map(|(i, struct_field)| {
                         let sp = struct_field.span.with_ctxt(self.span.ctxt());
-                        let binding_mode = if use_ref_pat {
-                            ast::BindingMode::ByRef(ast::Mutability::Not)
-                        } else {
-                            ast::BindingMode::ByValue(ast::Mutability::Not)
-                        };
                         let ident = self.mk_pattern_ident(prefix, i);
                         let path = ident.with_span_pos(sp);
                         (
                             sp,
                             struct_field.ident,
-                            cx.pat(path.span, PatKind::Ident(binding_mode, path, None)),
+                            cx.pat(
+                                path.span,
+                                PatKind::Ident(
+                                    BindingAnnotation(by_ref, Mutability::Not),
+                                    path,
+                                    None,
+                                ),
+                            ),
                         )
                     });
 
diff --git a/compiler/rustc_builtin_macros/src/global_allocator.rs b/compiler/rustc_builtin_macros/src/global_allocator.rs
index 2bad9bbce665..45b9b8ab6b64 100644
--- a/compiler/rustc_builtin_macros/src/global_allocator.rs
+++ b/compiler/rustc_builtin_macros/src/global_allocator.rs
@@ -9,6 +9,7 @@ use rustc_ast::{Fn, ItemKind, Mutability, Stmt, Ty, TyKind, Unsafe};
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::Span;
+use thin_vec::thin_vec;
 
 pub fn expand(
     ecx: &mut ExtCtxt<'_>,
@@ -116,7 +117,7 @@ impl AllocFnFactory<'_, '_> {
     fn attrs(&self) -> AttrVec {
         let special = sym::rustc_std_internal_symbol;
         let special = self.cx.meta_word(self.span, special);
-        vec![self.cx.attribute(special)].into()
+        thin_vec![self.cx.attribute(special)]
     }
 
     fn arg_ty(
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index 11565ba72d75..0de27d3d4070 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -9,13 +9,15 @@
 #![feature(if_let_guard)]
 #![feature(is_sorted)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![recursion_limit = "256"]
 
 extern crate proc_macro;
 
+#[macro_use]
+extern crate tracing;
+
 use crate::deriving::*;
 
 use rustc_expand::base::{MacroExpanderFn, ResolverExpand, SyntaxExtensionKind};
diff --git a/compiler/rustc_builtin_macros/src/standard_library_imports.rs b/compiler/rustc_builtin_macros/src/standard_library_imports.rs
index 90ea1e457ba8..49ef538f04e1 100644
--- a/compiler/rustc_builtin_macros/src/standard_library_imports.rs
+++ b/compiler/rustc_builtin_macros/src/standard_library_imports.rs
@@ -6,6 +6,7 @@ use rustc_span::edition::Edition::*;
 use rustc_span::hygiene::AstPass;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::DUMMY_SP;
+use thin_vec::thin_vec;
 
 pub fn inject(
     mut krate: ast::Crate,
@@ -51,7 +52,7 @@ pub fn inject(
             cx.item(
                 span,
                 ident,
-                vec![cx.attribute(cx.meta_word(span, sym::macro_use))].into(),
+                thin_vec![cx.attribute(cx.meta_word(span, sym::macro_use))],
                 ast::ItemKind::ExternCrate(None),
             ),
         );
@@ -78,7 +79,7 @@ pub fn inject(
     let use_item = cx.item(
         span,
         Ident::empty(),
-        vec![cx.attribute(cx.meta_word(span, sym::prelude_import))].into(),
+        thin_vec![cx.attribute(cx.meta_word(span, sym::prelude_import))],
         ast::ItemKind::Use(ast::UseTree {
             prefix: cx.path(span, import_path),
             kind: ast::UseTreeKind::Glob,
diff --git a/compiler/rustc_builtin_macros/src/test.rs b/compiler/rustc_builtin_macros/src/test.rs
index 03c84f5ec2a7..7efb6cc61eec 100644
--- a/compiler/rustc_builtin_macros/src/test.rs
+++ b/compiler/rustc_builtin_macros/src/test.rs
@@ -1,7 +1,6 @@
 /// The expansion from a test function to the appropriate test struct for libtest
 /// Ideally, this code would be in libtest but for efficiency and error messages it lives here.
 use crate::util::{check_builtin_macro_attribute, warn_on_duplicate_attribute};
-
 use rustc_ast as ast;
 use rustc_ast::attr;
 use rustc_ast::ptr::P;
@@ -11,8 +10,8 @@ use rustc_expand::base::*;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::Span;
-
 use std::iter;
+use thin_vec::thin_vec;
 
 // #[test_case] is used by custom test authors to mark tests
 // When building for test, it needs to make the item public and gensym the name
@@ -219,7 +218,7 @@ pub fn expand_test_or_bench(
     let mut test_const = cx.item(
         sp,
         Ident::new(item.ident.name, sp),
-        vec![
+        thin_vec![
             // #[cfg(test)]
             cx.attribute(attr::mk_list_item(
                 Ident::new(sym::cfg, attr_sp),
@@ -227,8 +226,7 @@ pub fn expand_test_or_bench(
             )),
             // #[rustc_test_marker]
             cx.attribute(cx.meta_word(attr_sp, sym::rustc_test_marker)),
-        ]
-        .into(),
+        ],
         // const $ident: test::TestDescAndFn =
         ast::ItemKind::Const(
             ast::Defaultness::Final,
@@ -337,7 +335,7 @@ pub fn expand_test_or_bench(
     // extern crate test
     let test_extern = cx.item(sp, test_id, ast::AttrVec::new(), ast::ItemKind::ExternCrate(None));
 
-    tracing::debug!("synthetic test item:\n{}\n", pprust::item_to_string(&test_const));
+    debug!("synthetic test item:\n{}\n", pprust::item_to_string(&test_const));
 
     if is_stmt {
         vec![
diff --git a/compiler/rustc_builtin_macros/src/test_harness.rs b/compiler/rustc_builtin_macros/src/test_harness.rs
index 093f0f10a386..561ca00c7197 100644
--- a/compiler/rustc_builtin_macros/src/test_harness.rs
+++ b/compiler/rustc_builtin_macros/src/test_harness.rs
@@ -14,7 +14,7 @@ use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::PanicStrategy;
 use smallvec::{smallvec, SmallVec};
-use tracing::debug;
+use thin_vec::thin_vec;
 
 use std::{iter, mem};
 
@@ -187,7 +187,10 @@ impl<'a> MutVisitor for EntryPointCleaner<'a> {
                     let dc_nested =
                         attr::mk_nested_word_item(Ident::new(sym::dead_code, self.def_site));
                     let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
-                    let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
+                    let allow_dead_code = attr::mk_attr_outer(
+                        &self.sess.parse_sess.attr_id_generator,
+                        allow_dead_code_item,
+                    );
                     let attrs = attrs
                         .into_iter()
                         .filter(|attr| {
@@ -335,7 +338,7 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
 
     let main = P(ast::Item {
         ident: main_id,
-        attrs: vec![main_attr].into(),
+        attrs: thin_vec![main_attr],
         id: ast::DUMMY_NODE_ID,
         kind: main,
         vis: ast::Visibility { span: sp, kind: ast::VisibilityKind::Public, tokens: None },
diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
index 815450f689e4..0497c2570e62 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs
@@ -342,7 +342,7 @@ pub(crate) fn codegen_terminator_call<'tcx>(
 
     let ret_place = codegen_place(fx, destination);
 
-    // Handle special calls like instrinsics and empty drop glue.
+    // Handle special calls like intrinsics and empty drop glue.
     let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
         let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
             .unwrap()
diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs
index c412e451a033..11540d800816 100644
--- a/compiler/rustc_codegen_cranelift/src/base.rs
+++ b/compiler/rustc_codegen_cranelift/src/base.rs
@@ -701,6 +701,10 @@ fn codegen_stmt<'tcx>(
                     let operand = codegen_operand(fx, operand);
                     operand.unsize_value(fx, lval);
                 }
+                Rvalue::Cast(CastKind::DynStar, _, _) => {
+                    // FIXME(dyn-star)
+                    unimplemented!()
+                }
                 Rvalue::Discriminant(place) => {
                     let place = codegen_place(fx, place);
                     let value = place.to_cvalue(fx);
@@ -794,20 +798,31 @@ fn codegen_stmt<'tcx>(
         | StatementKind::AscribeUserType(..) => {}
 
         StatementKind::Coverage { .. } => fx.tcx.sess.fatal("-Zcoverage is unimplemented"),
-        StatementKind::CopyNonOverlapping(inner) => {
-            let dst = codegen_operand(fx, &inner.dst);
-            let pointee = dst
-                .layout()
-                .pointee_info_at(fx, rustc_target::abi::Size::ZERO)
-                .expect("Expected pointer");
-            let dst = dst.load_scalar(fx);
-            let src = codegen_operand(fx, &inner.src).load_scalar(fx);
-            let count = codegen_operand(fx, &inner.count).load_scalar(fx);
-            let elem_size: u64 = pointee.size.bytes();
-            let bytes =
-                if elem_size != 1 { fx.bcx.ins().imul_imm(count, elem_size as i64) } else { count };
-            fx.bcx.call_memcpy(fx.target_config, dst, src, bytes);
-        }
+        StatementKind::Intrinsic(ref intrinsic) => match &**intrinsic {
+            // We ignore `assume` intrinsics, they are only useful for optimizations
+            NonDivergingIntrinsic::Assume(_) => {}
+            NonDivergingIntrinsic::CopyNonOverlapping(mir::CopyNonOverlapping {
+                src,
+                dst,
+                count,
+            }) => {
+                let dst = codegen_operand(fx, dst);
+                let pointee = dst
+                    .layout()
+                    .pointee_info_at(fx, rustc_target::abi::Size::ZERO)
+                    .expect("Expected pointer");
+                let dst = dst.load_scalar(fx);
+                let src = codegen_operand(fx, src).load_scalar(fx);
+                let count = codegen_operand(fx, count).load_scalar(fx);
+                let elem_size: u64 = pointee.size.bytes();
+                let bytes = if elem_size != 1 {
+                    fx.bcx.ins().imul_imm(count, elem_size as i64)
+                } else {
+                    count
+                };
+                fx.bcx.call_memcpy(fx.target_config, dst, src, bytes);
+            }
+        },
     }
 }
 
@@ -835,6 +850,7 @@ pub(crate) fn codegen_place<'tcx>(
             PlaceElem::Deref => {
                 cplace = cplace.place_deref(fx);
             }
+            PlaceElem::OpaqueCast(ty) => cplace = cplace.place_opaque_cast(fx, ty),
             PlaceElem::Field(field, _ty) => {
                 cplace = cplace.place_field(fx, field);
             }
diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index cb5d73a7e0ba..e12805b093cc 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -5,7 +5,6 @@ use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{
     read_target_uint, AllocId, ConstAllocation, ConstValue, ErrorHandled, GlobalAlloc, Scalar,
 };
-use rustc_middle::ty::ConstKind;
 use rustc_span::DUMMY_SP;
 
 use cranelift_codegen::ir::GlobalValueData;
@@ -41,36 +40,22 @@ impl ConstantCx {
 pub(crate) fn check_constants(fx: &mut FunctionCx<'_, '_, '_>) -> bool {
     let mut all_constants_ok = true;
     for constant in &fx.mir.required_consts {
-        let const_ = match fx.monomorphize(constant.literal) {
-            ConstantKind::Ty(ct) => ct,
+        let unevaluated = match fx.monomorphize(constant.literal) {
+            ConstantKind::Ty(_) => unreachable!(),
+            ConstantKind::Unevaluated(uv, _) => uv,
             ConstantKind::Val(..) => continue,
         };
-        match const_.kind() {
-            ConstKind::Value(_) => {}
-            ConstKind::Unevaluated(unevaluated) => {
-                if let Err(err) =
-                    fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None)
-                {
-                    all_constants_ok = false;
-                    match err {
-                        ErrorHandled::Reported(_) | ErrorHandled::Linted => {
-                            fx.tcx.sess.span_err(constant.span, "erroneous constant encountered");
-                        }
-                        ErrorHandled::TooGeneric => {
-                            span_bug!(
-                                constant.span,
-                                "codgen encountered polymorphic constant: {:?}",
-                                err
-                            );
-                        }
-                    }
+
+        if let Err(err) = fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None) {
+            all_constants_ok = false;
+            match err {
+                ErrorHandled::Reported(_) | ErrorHandled::Linted => {
+                    fx.tcx.sess.span_err(constant.span, "erroneous constant encountered");
+                }
+                ErrorHandled::TooGeneric => {
+                    span_bug!(constant.span, "codegen encountered polymorphic constant: {:?}", err);
                 }
             }
-            ConstKind::Param(_)
-            | ConstKind::Infer(_)
-            | ConstKind::Bound(_, _)
-            | ConstKind::Placeholder(_)
-            | ConstKind::Error(_) => unreachable!("{:?}", const_),
         }
     }
     all_constants_ok
@@ -122,36 +107,28 @@ pub(crate) fn codegen_constant<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
     constant: &Constant<'tcx>,
 ) -> CValue<'tcx> {
-    let const_ = match fx.monomorphize(constant.literal) {
-        ConstantKind::Ty(ct) => ct,
-        ConstantKind::Val(val, ty) => return codegen_const_value(fx, val, ty),
-    };
-    let const_val = match const_.kind() {
-        ConstKind::Value(valtree) => fx.tcx.valtree_to_const_val((const_.ty(), valtree)),
-        ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
+    let (const_val, ty) = match fx.monomorphize(constant.literal) {
+        ConstantKind::Ty(const_) => unreachable!("{:?}", const_),
+        ConstantKind::Unevaluated(mir::UnevaluatedConst { def, substs, promoted }, ty)
             if fx.tcx.is_static(def.did) =>
         {
             assert!(substs.is_empty());
             assert!(promoted.is_none());
 
-            return codegen_static_ref(fx, def.did, fx.layout_of(const_.ty())).to_cvalue(fx);
+            return codegen_static_ref(fx, def.did, fx.layout_of(ty)).to_cvalue(fx);
         }
-        ConstKind::Unevaluated(unevaluated) => {
+        ConstantKind::Unevaluated(unevaluated, ty) => {
             match fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None) {
-                Ok(const_val) => const_val,
+                Ok(const_val) => (const_val, ty),
                 Err(_) => {
                     span_bug!(constant.span, "erroneous constant not captured by required_consts");
                 }
             }
         }
-        ConstKind::Param(_)
-        | ConstKind::Infer(_)
-        | ConstKind::Bound(_, _)
-        | ConstKind::Placeholder(_)
-        | ConstKind::Error(_) => unreachable!("{:?}", const_),
+        ConstantKind::Val(val, ty) => (val, ty),
     };
 
-    codegen_const_value(fx, const_val, const_.ty())
+    codegen_const_value(fx, const_val, ty)
 }
 
 pub(crate) fn codegen_const_value<'tcx>(
@@ -496,6 +473,9 @@ pub(crate) fn mir_operand_get_const_val<'tcx>(
                 .eval_for_mir(fx.tcx, ParamEnv::reveal_all())
                 .try_to_value(fx.tcx),
             ConstantKind::Val(val, _) => Some(val),
+            ConstantKind::Unevaluated(uv, _) => {
+                fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), uv, None).ok()
+            }
         },
         // FIXME(rust-lang/rust#85105): Casts like `IMM8 as u32` result in the const being stored
         // inside a temporary before being passed to the intrinsic requiring the const argument.
@@ -536,9 +516,11 @@ pub(crate) fn mir_operand_get_const_val<'tcx>(
                         {
                             return None;
                         }
-                        StatementKind::CopyNonOverlapping(_) => {
-                            return None;
-                        } // conservative handling
+                        StatementKind::Intrinsic(ref intrinsic) => match **intrinsic {
+                            NonDivergingIntrinsic::CopyNonOverlapping(..) => return None,
+                            NonDivergingIntrinsic::Assume(..) => {}
+                        },
+                        // conservative handling
                         StatementKind::Assign(_)
                         | StatementKind::FakeRead(_)
                         | StatementKind::SetDiscriminant { .. }
diff --git a/compiler/rustc_codegen_cranelift/src/debuginfo/line_info.rs b/compiler/rustc_codegen_cranelift/src/debuginfo/line_info.rs
index 3ad0c420eaf0..463de6a91c74 100644
--- a/compiler/rustc_codegen_cranelift/src/debuginfo/line_info.rs
+++ b/compiler/rustc_codegen_cranelift/src/debuginfo/line_info.rs
@@ -68,9 +68,9 @@ impl DebugContext {
     ) -> (Lrc<SourceFile>, u64, u64) {
         // Based on https://github.com/rust-lang/rust/blob/e369d87b015a84653343032833d65d0545fd3f26/src/librustc_codegen_ssa/mir/mod.rs#L116-L131
         // In order to have a good line stepping behavior in debugger, we overwrite debug
-        // locations of macro expansions with that of the outermost expansion site
-        // (unless the crate is being compiled with `-Z debug-macros`).
-        let span = if !span.from_expansion() || tcx.sess.opts.unstable_opts.debug_macros {
+        // locations of macro expansions with that of the outermost expansion site (when the macro is
+        // annotated with `#[collapse_debuginfo]` or when `-Zdebug-macros` is provided).
+        let span = if tcx.should_collapse_debuginfo(span) {
             span
         } else {
             // Walk up the macro expansion chain until we reach a non-expanded span.
diff --git a/compiler/rustc_codegen_cranelift/src/discriminant.rs b/compiler/rustc_codegen_cranelift/src/discriminant.rs
index e41ae1fbdbac..97b395bcd051 100644
--- a/compiler/rustc_codegen_cranelift/src/discriminant.rs
+++ b/compiler/rustc_codegen_cranelift/src/discriminant.rs
@@ -42,10 +42,10 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
         Variants::Multiple {
             tag: _,
             tag_field,
-            tag_encoding: TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start },
+            tag_encoding: TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start },
             variants: _,
         } => {
-            if variant_index != dataful_variant {
+            if variant_index != untagged_variant {
                 let niche = place.place_field(fx, mir::Field::new(tag_field));
                 let niche_value = variant_index.as_u32() - niche_variants.start().as_u32();
                 let niche_value = ty::ScalarInt::try_from_uint(
@@ -113,7 +113,7 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
             let res = CValue::by_val(val, dest_layout);
             dest.write_cvalue(fx, res);
         }
-        TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
+        TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start } => {
             // Rebase from niche values to discriminants, and check
             // whether the result is in range for the niche variants.
 
@@ -169,8 +169,9 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
                 fx.bcx.ins().iadd_imm(relative_discr, i64::from(niche_variants.start().as_u32()))
             };
 
-            let dataful_variant = fx.bcx.ins().iconst(cast_to, i64::from(dataful_variant.as_u32()));
-            let discr = fx.bcx.ins().select(is_niche, niche_discr, dataful_variant);
+            let untagged_variant =
+                fx.bcx.ins().iconst(cast_to, i64::from(untagged_variant.as_u32()));
+            let discr = fx.bcx.ins().select(is_niche, niche_discr, untagged_variant);
             let res = CValue::by_val(discr, dest_layout);
             dest.write_cvalue(fx, res);
         }
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
index 95239f415a99..2e4ca594f91b 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
@@ -203,7 +203,7 @@ pub(crate) fn codegen_intrinsic_call<'tcx>(
             sym::transmute => {
                 crate::base::codegen_panic(fx, "Transmuting to uninhabited type.", source_info);
             }
-            _ => unimplemented!("unsupported instrinsic {}", intrinsic),
+            _ => unimplemented!("unsupported intrinsic {}", intrinsic),
         }
         return;
     };
@@ -357,9 +357,6 @@ fn codegen_regular_intrinsic_call<'tcx>(
     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 
     match intrinsic {
-        sym::assume => {
-            intrinsic_args!(fx, args => (_a); intrinsic);
-        }
         sym::likely | sym::unlikely => {
             intrinsic_args!(fx, args => (a); intrinsic);
 
@@ -819,20 +816,13 @@ fn codegen_regular_intrinsic_call<'tcx>(
             ret.write_cvalue(fx, val);
         }
 
-        sym::ptr_guaranteed_eq => {
+        sym::ptr_guaranteed_cmp => {
             intrinsic_args!(fx, args => (a, b); intrinsic);
 
             let val = crate::num::codegen_ptr_binop(fx, BinOp::Eq, a, b);
             ret.write_cvalue(fx, val);
         }
 
-        sym::ptr_guaranteed_ne => {
-            intrinsic_args!(fx, args => (a, b); intrinsic);
-
-            let val = crate::num::codegen_ptr_binop(fx, BinOp::Ne, a, b);
-            ret.write_cvalue(fx, val);
-        }
-
         sym::caller_location => {
             intrinsic_args!(fx, args => (); intrinsic);
 
diff --git a/compiler/rustc_codegen_cranelift/src/main_shim.rs b/compiler/rustc_codegen_cranelift/src/main_shim.rs
index c67b6e98b32c..3c024a84d909 100644
--- a/compiler/rustc_codegen_cranelift/src/main_shim.rs
+++ b/compiler/rustc_codegen_cranelift/src/main_shim.rs
@@ -1,7 +1,7 @@
 use rustc_hir::LangItem;
 use rustc_middle::ty::subst::GenericArg;
 use rustc_middle::ty::AssocKind;
-use rustc_session::config::EntryFnType;
+use rustc_session::config::{sigpipe, EntryFnType};
 use rustc_span::symbol::Ident;
 
 use crate::prelude::*;
@@ -15,12 +15,12 @@ pub(crate) fn maybe_create_entry_wrapper(
     is_jit: bool,
     is_primary_cgu: bool,
 ) {
-    let (main_def_id, is_main_fn) = match tcx.entry_fn(()) {
+    let (main_def_id, (is_main_fn, sigpipe)) = match tcx.entry_fn(()) {
         Some((def_id, entry_ty)) => (
             def_id,
             match entry_ty {
-                EntryFnType::Main => true,
-                EntryFnType::Start => false,
+                EntryFnType::Main { sigpipe } => (true, sigpipe),
+                EntryFnType::Start => (false, sigpipe::DEFAULT),
             },
         ),
         None => return,
@@ -35,7 +35,7 @@ pub(crate) fn maybe_create_entry_wrapper(
         return;
     }
 
-    create_entry_fn(tcx, module, unwind_context, main_def_id, is_jit, is_main_fn);
+    create_entry_fn(tcx, module, unwind_context, main_def_id, is_jit, is_main_fn, sigpipe);
 
     fn create_entry_fn(
         tcx: TyCtxt<'_>,
@@ -44,6 +44,7 @@ pub(crate) fn maybe_create_entry_wrapper(
         rust_main_def_id: DefId,
         ignore_lang_start_wrapper: bool,
         is_main_fn: bool,
+        sigpipe: u8,
     ) {
         let main_ret_ty = tcx.fn_sig(rust_main_def_id).output();
         // Given that `main()` has no arguments,
@@ -83,6 +84,7 @@ pub(crate) fn maybe_create_entry_wrapper(
             bcx.switch_to_block(block);
             let arg_argc = bcx.append_block_param(block, m.target_config().pointer_type());
             let arg_argv = bcx.append_block_param(block, m.target_config().pointer_type());
+            let arg_sigpipe = bcx.ins().iconst(types::I8, sigpipe as i64);
 
             let main_func_ref = m.declare_func_in_func(main_func_id, &mut bcx.func);
 
@@ -143,7 +145,8 @@ pub(crate) fn maybe_create_entry_wrapper(
                 let main_val = bcx.ins().func_addr(m.target_config().pointer_type(), main_func_ref);
 
                 let func_ref = m.declare_func_in_func(start_func_id, &mut bcx.func);
-                let call_inst = bcx.ins().call(func_ref, &[main_val, arg_argc, arg_argv]);
+                let call_inst =
+                    bcx.ins().call(func_ref, &[main_val, arg_argc, arg_argv, arg_sigpipe]);
                 bcx.inst_results(call_inst)[0]
             } else {
                 // using user-defined start fn
diff --git a/compiler/rustc_codegen_cranelift/src/value_and_place.rs b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
index 2ee98546c992..3fa3e3657cb6 100644
--- a/compiler/rustc_codegen_cranelift/src/value_and_place.rs
+++ b/compiler/rustc_codegen_cranelift/src/value_and_place.rs
@@ -621,6 +621,14 @@ impl<'tcx> CPlace<'tcx> {
         }
     }
 
+    pub(crate) fn place_opaque_cast(
+        self,
+        fx: &mut FunctionCx<'_, '_, 'tcx>,
+        ty: Ty<'tcx>,
+    ) -> CPlace<'tcx> {
+        CPlace { inner: self.inner, layout: fx.layout_of(ty) }
+    }
+
     pub(crate) fn place_field(
         self,
         fx: &mut FunctionCx<'_, '_, 'tcx>,
@@ -815,7 +823,8 @@ pub(crate) fn assert_assignable<'tcx>(
             );
             // fn(&T) -> for<'l> fn(&'l T) is allowed
         }
-        (&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => {
+        (&ty::Dynamic(from_traits, _, _from_kind), &ty::Dynamic(to_traits, _, _to_kind)) => {
+            // FIXME(dyn-star): Do the right thing with DynKinds
             for (from, to) in from_traits.iter().zip(to_traits) {
                 let from =
                     fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from);
diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs
index ccb6cbbc2c8a..aa1c271c31cb 100644
--- a/compiler/rustc_codegen_gcc/src/common.rs
+++ b/compiler/rustc_codegen_gcc/src/common.rs
@@ -158,10 +158,6 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         None
     }
 
-    fn zst_to_backend(&self, _ty: Type<'gcc>) -> RValue<'gcc> {
-        self.const_undef(self.type_ix(0))
-    }
-
     fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, ty: Type<'gcc>) -> RValue<'gcc> {
         let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() };
         match cv {
diff --git a/compiler/rustc_codegen_llvm/Cargo.toml b/compiler/rustc_codegen_llvm/Cargo.toml
index 74115353aaf7..a068aa2ec624 100644
--- a/compiler/rustc_codegen_llvm/Cargo.toml
+++ b/compiler/rustc_codegen_llvm/Cargo.toml
@@ -11,7 +11,6 @@ doctest = false
 bitflags = "1.0"
 cstr = "0.2"
 libc = "0.2"
-libloading = "0.7.1"
 measureme = "10.0.0"
 object = { version = "0.29.0", default-features = false, features = ["std", "read_core", "archive", "coff", "elf", "macho", "pe"] }
 tracing = "0.1"
diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index 0ce161d7e756..26f5225f6b44 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -19,6 +19,7 @@ use rustc_target::abi::call::ArgAbi;
 pub use rustc_target::abi::call::*;
 use rustc_target::abi::{self, HasDataLayout, Int};
 pub use rustc_target::spec::abi::Abi;
+use rustc_target::spec::SanitizerSet;
 
 use libc::c_uint;
 use smallvec::SmallVec;
@@ -90,6 +91,13 @@ fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'
         if regular.contains(ArgAttribute::NoAliasMutRef) && should_use_mutable_noalias(cx) {
             attrs.push(llvm::AttributeKind::NoAlias.create_attr(cx.llcx));
         }
+    } else if cx.tcx.sess.opts.unstable_opts.sanitizer.contains(SanitizerSet::MEMORY) {
+        // If we're not optimising, *but* memory sanitizer is on, emit noundef, since it affects
+        // memory sanitizer's behavior.
+
+        if regular.contains(ArgAttribute::NoUndef) {
+            attrs.push(llvm::AttributeKind::NoUndef.create_attr(cx.llcx));
+        }
     }
 
     attrs
diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index 2a6612eb86f1..5202ac697e94 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -19,7 +19,6 @@ use rustc_target::asm::*;
 
 use libc::{c_char, c_uint};
 use smallvec::SmallVec;
-use tracing::debug;
 
 impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
     fn codegen_inline_asm(
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index aabbe8ac276d..eff2436d41ca 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -35,6 +35,10 @@ pub fn apply_to_callsite(callsite: &Value, idx: AttributePlace, attrs: &[&Attrib
 /// Get LLVM attribute for the provided inline heuristic.
 #[inline]
 fn inline_attr<'ll>(cx: &CodegenCx<'ll, '_>, inline: InlineAttr) -> Option<&'ll Attribute> {
+    if !cx.tcx.sess.opts.unstable_opts.inline_llvm {
+        // disable LLVM inlining
+        return Some(AttributeKind::NoInline.create_attr(cx.llcx));
+    }
     match inline {
         InlineAttr::Hint => Some(AttributeKind::InlineHint.create_attr(cx.llcx)),
         InlineAttr::Always => Some(AttributeKind::AlwaysInline.create_attr(cx.llcx)),
@@ -386,7 +390,8 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     ) {
         let span = cx
             .tcx
-            .get_attr(instance.def_id(), sym::target_feature)
+            .get_attrs(instance.def_id(), sym::target_feature)
+            .next()
             .map_or_else(|| cx.tcx.def_span(instance.def_id()), |a| a.span);
         let msg = format!(
             "the target features {} must all be either enabled or disabled together",
diff --git a/compiler/rustc_codegen_llvm/src/back/archive.rs b/compiler/rustc_codegen_llvm/src/back/archive.rs
index 2e614e5dd88e..38a366095b41 100644
--- a/compiler/rustc_codegen_llvm/src/back/archive.rs
+++ b/compiler/rustc_codegen_llvm/src/back/archive.rs
@@ -190,10 +190,10 @@ impl ArchiveBuilderBuilder for LlvmArchiveBuilderBuilder {
 
             let output_path_z = rustc_fs_util::path_to_c_string(&output_path);
 
-            tracing::trace!("invoking LLVMRustWriteImportLibrary");
-            tracing::trace!("  dll_name {:#?}", dll_name_z);
-            tracing::trace!("  output_path {}", output_path.display());
-            tracing::trace!(
+            trace!("invoking LLVMRustWriteImportLibrary");
+            trace!("  dll_name {:#?}", dll_name_z);
+            trace!("  output_path {}", output_path.display());
+            trace!(
                 "  import names: {}",
                 dll_imports
                     .iter()
diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index e4af6269abc5..2049422b79a3 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -1,8 +1,6 @@
-use crate::back::write::{
-    self, save_temp_bitcode, to_llvm_opt_settings, with_llvm_pmb, DiagnosticHandlers,
-};
-use crate::llvm::{self, build_string, False, True};
-use crate::{llvm_util, LlvmCodegenBackend, ModuleLlvm};
+use crate::back::write::{self, save_temp_bitcode, DiagnosticHandlers};
+use crate::llvm::{self, build_string};
+use crate::{LlvmCodegenBackend, ModuleLlvm};
 use object::read::archive::ArchiveFile;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule, ThinShared};
 use rustc_codegen_ssa::back::symbol_export;
@@ -18,7 +16,6 @@ use rustc_middle::dep_graph::WorkProduct;
 use rustc_middle::middle::exported_symbols::{SymbolExportInfo, SymbolExportLevel};
 use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{self, CrateType, Lto};
-use tracing::{debug, info};
 
 use std::ffi::{CStr, CString};
 use std::fs::File;
@@ -598,61 +595,9 @@ pub(crate) fn run_pass_manager(
                 1,
             );
         }
-        if llvm_util::should_use_new_llvm_pass_manager(
-            &config.new_llvm_pass_manager,
-            &cgcx.target_arch,
-        ) {
-            let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
-            let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);
-            write::optimize_with_new_llvm_pass_manager(
-                cgcx,
-                diag_handler,
-                module,
-                config,
-                opt_level,
-                opt_stage,
-            )?;
-            debug!("lto done");
-            return Ok(());
-        }
-
-        let pm = llvm::LLVMCreatePassManager();
-        llvm::LLVMAddAnalysisPasses(module.module_llvm.tm, pm);
-
-        if config.verify_llvm_ir {
-            let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr().cast());
-            llvm::LLVMRustAddPass(pm, pass.unwrap());
-        }
-
-        let opt_level = config
-            .opt_level
-            .map(|x| to_llvm_opt_settings(x).0)
-            .unwrap_or(llvm::CodeGenOptLevel::None);
-        with_llvm_pmb(module.module_llvm.llmod(), config, opt_level, false, &mut |b| {
-            if thin {
-                llvm::LLVMRustPassManagerBuilderPopulateThinLTOPassManager(b, pm);
-            } else {
-                llvm::LLVMRustPassManagerBuilderPopulateLTOPassManager(
-                    b, pm, /* Internalize = */ False, /* RunInliner = */ True,
-                );
-            }
-        });
-
-        // We always generate bitcode through ThinLTOBuffers,
-        // which do not support anonymous globals
-        if config.bitcode_needed() {
-            let pass = llvm::LLVMRustFindAndCreatePass("name-anon-globals\0".as_ptr().cast());
-            llvm::LLVMRustAddPass(pm, pass.unwrap());
-        }
-
-        if config.verify_llvm_ir {
-            let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr().cast());
-            llvm::LLVMRustAddPass(pm, pass.unwrap());
-        }
-
-        llvm::LLVMRunPassManager(pm, module.module_llvm.llmod());
-
-        llvm::LLVMDisposePassManager(pm);
+        let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
+        let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);
+        write::llvm_optimize(cgcx, diag_handler, module, config, opt_level, opt_stage)?;
     }
     debug!("lto done");
     Ok(())
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index 740a68d0772c..db526746fa70 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -21,14 +21,12 @@ use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_errors::{FatalError, Handler, Level};
 use rustc_fs_util::{link_or_copy, path_to_c_string};
-use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{self, Lto, OutputType, Passes, SplitDwarfKind, SwitchWithOptPath};
 use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::InnerSpan;
 use rustc_target::spec::{CodeModel, RelocModel, SanitizerSet, SplitDebuginfo};
-use tracing::debug;
 
 use libc::{c_char, c_int, c_uint, c_void, size_t};
 use std::ffi::CString;
@@ -418,7 +416,7 @@ fn get_instr_profile_output_path(config: &ModuleConfig) -> Option<CString> {
     }
 }
 
-pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
+pub(crate) unsafe fn llvm_optimize(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     diag_handler: &Handler,
     module: &ModuleCodegen<ModuleLlvm>,
@@ -466,7 +464,7 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
     // FIXME: NewPM doesn't provide a facility to pass custom InlineParams.
     // We would have to add upstream support for this first, before we can support
     // config.inline_threshold and our more aggressive default thresholds.
-    let result = llvm::LLVMRustOptimizeWithNewPassManager(
+    let result = llvm::LLVMRustOptimize(
         module.module_llvm.llmod(),
         &*module.module_llvm.tm,
         to_pass_builder_opt_level(opt_level),
@@ -510,18 +508,11 @@ pub(crate) unsafe fn optimize(
 
     let llmod = module.module_llvm.llmod();
     let llcx = &*module.module_llvm.llcx;
-    let tm = &*module.module_llvm.tm;
     let _handlers = DiagnosticHandlers::new(cgcx, diag_handler, llcx);
 
     let module_name = module.name.clone();
     let module_name = Some(&module_name[..]);
 
-    if let Some(false) = config.new_llvm_pass_manager && llvm_util::get_version() >= (15, 0, 0) {
-        diag_handler.warn(
-            "ignoring `-Z new-llvm-pass-manager=no`, which is no longer supported with LLVM 15",
-        );
-    }
-
     if config.emit_no_opt_bc {
         let out = cgcx.output_filenames.temp_path_ext("no-opt.bc", module_name);
         let out = path_to_c_string(&out);
@@ -529,184 +520,17 @@ pub(crate) unsafe fn optimize(
     }
 
     if let Some(opt_level) = config.opt_level {
-        if llvm_util::should_use_new_llvm_pass_manager(
-            &config.new_llvm_pass_manager,
-            &cgcx.target_arch,
-        ) {
-            let opt_stage = match cgcx.lto {
-                Lto::Fat => llvm::OptStage::PreLinkFatLTO,
-                Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,
-                _ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
-                _ => llvm::OptStage::PreLinkNoLTO,
-            };
-            return optimize_with_new_llvm_pass_manager(
-                cgcx,
-                diag_handler,
-                module,
-                config,
-                opt_level,
-                opt_stage,
-            );
-        }
-
-        if cgcx.prof.llvm_recording_enabled() {
-            diag_handler
-                .warn("`-Z self-profile-events = llvm` requires `-Z new-llvm-pass-manager`");
-        }
-
-        // Create the two optimizing pass managers. These mirror what clang
-        // does, and are by populated by LLVM's default PassManagerBuilder.
-        // Each manager has a different set of passes, but they also share
-        // some common passes.
-        let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
-        let mpm = llvm::LLVMCreatePassManager();
-
-        {
-            let find_pass = |pass_name: &str| {
-                let pass_name = SmallCStr::new(pass_name);
-                llvm::LLVMRustFindAndCreatePass(pass_name.as_ptr())
-            };
-
-            if config.verify_llvm_ir {
-                // Verification should run as the very first pass.
-                llvm::LLVMRustAddPass(fpm, find_pass("verify").unwrap());
-            }
-
-            let mut extra_passes = Vec::new();
-            let mut have_name_anon_globals_pass = false;
-
-            for pass_name in &config.passes {
-                if pass_name == "lint" {
-                    // Linting should also be performed early, directly on the generated IR.
-                    llvm::LLVMRustAddPass(fpm, find_pass("lint").unwrap());
-                    continue;
-                }
-
-                if let Some(pass) = find_pass(pass_name) {
-                    extra_passes.push(pass);
-                } else {
-                    diag_handler.warn(&format!("unknown pass `{}`, ignoring", pass_name));
-                }
-
-                if pass_name == "name-anon-globals" {
-                    have_name_anon_globals_pass = true;
-                }
-            }
-
-            // Instrumentation must be inserted before optimization,
-            // otherwise LLVM may optimize some functions away which
-            // breaks llvm-cov.
-            //
-            // This mirrors what Clang does in lib/CodeGen/BackendUtil.cpp.
-            if config.instrument_gcov {
-                llvm::LLVMRustAddPass(mpm, find_pass("insert-gcov-profiling").unwrap());
-            }
-            if config.instrument_coverage {
-                llvm::LLVMRustAddPass(mpm, find_pass("instrprof").unwrap());
-            }
-            if config.debug_info_for_profiling {
-                llvm::LLVMRustAddPass(mpm, find_pass("add-discriminators").unwrap());
-            }
-
-            add_sanitizer_passes(config, &mut extra_passes);
-
-            // Some options cause LLVM bitcode to be emitted, which uses ThinLTOBuffers, so we need
-            // to make sure we run LLVM's NameAnonGlobals pass when emitting bitcode; otherwise
-            // we'll get errors in LLVM.
-            let using_thin_buffers = config.bitcode_needed();
-            if !config.no_prepopulate_passes {
-                llvm::LLVMAddAnalysisPasses(tm, fpm);
-                llvm::LLVMAddAnalysisPasses(tm, mpm);
-                let opt_level = to_llvm_opt_settings(opt_level).0;
-                let prepare_for_thin_lto = cgcx.lto == Lto::Thin
-                    || cgcx.lto == Lto::ThinLocal
-                    || (cgcx.lto != Lto::Fat && cgcx.opts.cg.linker_plugin_lto.enabled());
-                with_llvm_pmb(llmod, config, opt_level, prepare_for_thin_lto, &mut |b| {
-                    llvm::LLVMRustAddLastExtensionPasses(
-                        b,
-                        extra_passes.as_ptr(),
-                        extra_passes.len() as size_t,
-                    );
-                    llvm::LLVMRustPassManagerBuilderPopulateFunctionPassManager(b, fpm);
-                    llvm::LLVMRustPassManagerBuilderPopulateModulePassManager(b, mpm);
-                });
-
-                have_name_anon_globals_pass = have_name_anon_globals_pass || prepare_for_thin_lto;
-                if using_thin_buffers && !prepare_for_thin_lto {
-                    llvm::LLVMRustAddPass(mpm, find_pass("name-anon-globals").unwrap());
-                    have_name_anon_globals_pass = true;
-                }
-            } else {
-                // If we don't use the standard pipeline, directly populate the MPM
-                // with the extra passes.
-                for pass in extra_passes {
-                    llvm::LLVMRustAddPass(mpm, pass);
-                }
-            }
-
-            if using_thin_buffers && !have_name_anon_globals_pass {
-                // As described above, this will probably cause an error in LLVM
-                if config.no_prepopulate_passes {
-                    diag_handler.err(
-                        "The current compilation is going to use thin LTO buffers \
-                                      without running LLVM's NameAnonGlobals pass. \
-                                      This will likely cause errors in LLVM. Consider adding \
-                                      -C passes=name-anon-globals to the compiler command line.",
-                    );
-                } else {
-                    bug!(
-                        "We are using thin LTO buffers without running the NameAnonGlobals pass. \
-                          This will likely cause errors in LLVM and should never happen."
-                    );
-                }
-            }
-        }
-
-        diag_handler.abort_if_errors();
-
-        // Finally, run the actual optimization passes
-        {
-            let _timer = cgcx.prof.extra_verbose_generic_activity(
-                "LLVM_module_optimize_function_passes",
-                &*module.name,
-            );
-            llvm::LLVMRustRunFunctionPassManager(fpm, llmod);
-        }
-        {
-            let _timer = cgcx.prof.extra_verbose_generic_activity(
-                "LLVM_module_optimize_module_passes",
-                &*module.name,
-            );
-            llvm::LLVMRunPassManager(mpm, llmod);
-        }
-
-        // Deallocate managers that we're now done with
-        llvm::LLVMDisposePassManager(fpm);
-        llvm::LLVMDisposePassManager(mpm);
+        let opt_stage = match cgcx.lto {
+            Lto::Fat => llvm::OptStage::PreLinkFatLTO,
+            Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,
+            _ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
+            _ => llvm::OptStage::PreLinkNoLTO,
+        };
+        return llvm_optimize(cgcx, diag_handler, module, config, opt_level, opt_stage);
     }
     Ok(())
 }
 
-unsafe fn add_sanitizer_passes(config: &ModuleConfig, passes: &mut Vec<&'static mut llvm::Pass>) {
-    if config.sanitizer.contains(SanitizerSet::ADDRESS) {
-        let recover = config.sanitizer_recover.contains(SanitizerSet::ADDRESS);
-        passes.push(llvm::LLVMRustCreateAddressSanitizerFunctionPass(recover));
-        passes.push(llvm::LLVMRustCreateModuleAddressSanitizerPass(recover));
-    }
-    if config.sanitizer.contains(SanitizerSet::MEMORY) {
-        let track_origins = config.sanitizer_memory_track_origins as c_int;
-        let recover = config.sanitizer_recover.contains(SanitizerSet::MEMORY);
-        passes.push(llvm::LLVMRustCreateMemorySanitizerPass(track_origins, recover));
-    }
-    if config.sanitizer.contains(SanitizerSet::THREAD) {
-        passes.push(llvm::LLVMRustCreateThreadSanitizerPass());
-    }
-    if config.sanitizer.contains(SanitizerSet::HWADDRESS) {
-        let recover = config.sanitizer_recover.contains(SanitizerSet::HWADDRESS);
-        passes.push(llvm::LLVMRustCreateHWAddressSanitizerPass(recover));
-    }
-}
-
 pub(crate) fn link(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     diag_handler: &Handler,
@@ -1073,72 +897,6 @@ unsafe fn embed_bitcode(
     }
 }
 
-pub unsafe fn with_llvm_pmb(
-    llmod: &llvm::Module,
-    config: &ModuleConfig,
-    opt_level: llvm::CodeGenOptLevel,
-    prepare_for_thin_lto: bool,
-    f: &mut dyn FnMut(&llvm::PassManagerBuilder),
-) {
-    use std::ptr;
-
-    // Create the PassManagerBuilder for LLVM. We configure it with
-    // reasonable defaults and prepare it to actually populate the pass
-    // manager.
-    let builder = llvm::LLVMRustPassManagerBuilderCreate();
-    let opt_size = config.opt_size.map_or(llvm::CodeGenOptSizeNone, |x| to_llvm_opt_settings(x).1);
-    let inline_threshold = config.inline_threshold;
-    let pgo_gen_path = get_pgo_gen_path(config);
-    let pgo_use_path = get_pgo_use_path(config);
-    let pgo_sample_use_path = get_pgo_sample_use_path(config);
-
-    llvm::LLVMRustConfigurePassManagerBuilder(
-        builder,
-        opt_level,
-        config.merge_functions,
-        config.vectorize_slp,
-        config.vectorize_loop,
-        prepare_for_thin_lto,
-        pgo_gen_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
-        pgo_use_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
-        pgo_sample_use_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
-        opt_size as c_int,
-    );
-
-    llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, config.no_builtins);
-
-    // Here we match what clang does (kinda). For O0 we only inline
-    // always-inline functions (but don't add lifetime intrinsics), at O1 we
-    // inline with lifetime intrinsics, and O2+ we add an inliner with a
-    // thresholds copied from clang.
-    match (opt_level, opt_size, inline_threshold) {
-        (.., Some(t)) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, t);
-        }
-        (llvm::CodeGenOptLevel::Aggressive, ..) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 275);
-        }
-        (_, llvm::CodeGenOptSizeDefault, _) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 75);
-        }
-        (_, llvm::CodeGenOptSizeAggressive, _) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 25);
-        }
-        (llvm::CodeGenOptLevel::None, ..) => {
-            llvm::LLVMRustAddAlwaysInlinePass(builder, config.emit_lifetime_markers);
-        }
-        (llvm::CodeGenOptLevel::Less, ..) => {
-            llvm::LLVMRustAddAlwaysInlinePass(builder, config.emit_lifetime_markers);
-        }
-        (llvm::CodeGenOptLevel::Default, ..) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 225);
-        }
-    }
-
-    f(builder);
-    llvm::LLVMRustPassManagerBuilderDispose(builder);
-}
-
 // Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
 // This is required to satisfy `dllimport` references to static data in .rlibs
 // when using MSVC linker.  We do this only for data, as linker can fix up
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index e7e373bf45d1..59b1c7fb5dbd 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -1,14 +1,13 @@
 use crate::attributes;
 use crate::common::Funclet;
 use crate::context::CodegenCx;
-use crate::llvm::{self, BasicBlock, False};
-use crate::llvm::{AtomicOrdering, AtomicRmwBinOp, SynchronizationScope};
+use crate::llvm::{self, AtomicOrdering, AtomicRmwBinOp, BasicBlock};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
 use cstr::cstr;
 use libc::{c_char, c_uint};
-use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, TypeKind};
+use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, SynchronizationScope, TypeKind};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::*;
@@ -27,7 +26,6 @@ use std::ffi::CStr;
 use std::iter;
 use std::ops::Deref;
 use std::ptr;
-use tracing::{debug, instrument};
 
 // All Builders must have an llfn associated with them
 #[must_use]
@@ -1043,15 +1041,17 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     ) -> &'ll Value {
         let weak = if weak { llvm::True } else { llvm::False };
         unsafe {
-            llvm::LLVMRustBuildAtomicCmpXchg(
+            let value = llvm::LLVMBuildAtomicCmpXchg(
                 self.llbuilder,
                 dst,
                 cmp,
                 src,
                 AtomicOrdering::from_generic(order),
                 AtomicOrdering::from_generic(failure_order),
-                weak,
-            )
+                llvm::False, // SingleThreaded
+            );
+            llvm::LLVMSetWeak(value, weak);
+            value
         }
     }
     fn atomic_rmw(
@@ -1068,7 +1068,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 dst,
                 src,
                 AtomicOrdering::from_generic(order),
-                False,
+                llvm::False, // SingleThreaded
             )
         }
     }
@@ -1076,13 +1076,18 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn atomic_fence(
         &mut self,
         order: rustc_codegen_ssa::common::AtomicOrdering,
-        scope: rustc_codegen_ssa::common::SynchronizationScope,
+        scope: SynchronizationScope,
     ) {
+        let single_threaded = match scope {
+            SynchronizationScope::SingleThread => llvm::True,
+            SynchronizationScope::CrossThread => llvm::False,
+        };
         unsafe {
-            llvm::LLVMRustBuildAtomicFence(
+            llvm::LLVMBuildFence(
                 self.llbuilder,
                 AtomicOrdering::from_generic(order),
-                SynchronizationScope::from_generic(scope),
+                single_threaded,
+                UNNAMED,
             );
         }
     }
diff --git a/compiler/rustc_codegen_llvm/src/callee.rs b/compiler/rustc_codegen_llvm/src/callee.rs
index d55f995b933a..b83c1e8f08f3 100644
--- a/compiler/rustc_codegen_llvm/src/callee.rs
+++ b/compiler/rustc_codegen_llvm/src/callee.rs
@@ -11,7 +11,6 @@ use crate::context::CodegenCx;
 use crate::llvm;
 use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
-use tracing::debug;
 
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
 use rustc_middle::ty::{self, Instance, TypeVisitable};
diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
index 63d3bb40a3fe..acee9134fb96 100644
--- a/compiler/rustc_codegen_llvm/src/common.rs
+++ b/compiler/rustc_codegen_llvm/src/common.rs
@@ -21,7 +21,6 @@ use rustc_target::spec::Target;
 
 use libc::{c_char, c_uint};
 use std::fmt::Write;
-use tracing::debug;
 
 /*
 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
@@ -216,7 +215,11 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     }
 
     fn const_to_opt_uint(&self, v: &'ll Value) -> Option<u64> {
-        try_as_const_integral(v).map(|v| unsafe { llvm::LLVMConstIntGetZExtValue(v) })
+        try_as_const_integral(v).and_then(|v| unsafe {
+            let mut i = 0u64;
+            let success = llvm::LLVMRustConstIntGetZExtValue(v, &mut i);
+            success.then_some(i)
+        })
     }
 
     fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> {
@@ -227,10 +230,6 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         })
     }
 
-    fn zst_to_backend(&self, _llty: &'ll Type) -> &'ll Value {
-        self.const_undef(self.type_ix(0))
-    }
-
     fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, llty: &'ll Type) -> &'ll Value {
         let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() };
         match cv {
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs
index d3e33da27993..a559f7f3d570 100644
--- a/compiler/rustc_codegen_llvm/src/consts.rs
+++ b/compiler/rustc_codegen_llvm/src/consts.rs
@@ -23,7 +23,6 @@ use rustc_target::abi::{
     AddressSpace, Align, HasDataLayout, Primitive, Scalar, Size, WrappingRange,
 };
 use std::ops::Range;
-use tracing::debug;
 
 pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<'_>) -> &'ll Value {
     let alloc = alloc.inner();
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index 58f391692c49..0d1df6fb1acd 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -16,8 +16,6 @@ use rustc_middle::ty::TyCtxt;
 
 use std::ffi::CString;
 
-use tracing::debug;
-
 /// Generates and exports the Coverage Map.
 ///
 /// Rust Coverage Map generation supports LLVM Coverage Mapping Format versions
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index 98ba38356a4c..964a632b6eed 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -28,7 +28,6 @@ use std::cell::RefCell;
 use std::ffi::CString;
 
 use std::iter;
-use tracing::debug;
 
 pub mod mapgen;
 
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index d0a6f216858b..163ccd9460c5 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -42,7 +42,6 @@ use rustc_span::{self, FileNameDisplayPreference, SourceFile};
 use rustc_symbol_mangling::typeid_for_trait_ref;
 use rustc_target::abi::{Align, Size};
 use smallvec::smallvec;
-use tracing::debug;
 
 use libc::{c_char, c_longlong, c_uint};
 use std::borrow::Cow;
@@ -51,7 +50,6 @@ use std::hash::{Hash, Hasher};
 use std::iter;
 use std::path::{Path, PathBuf};
 use std::ptr;
-use tracing::instrument;
 
 impl PartialEq for llvm::Metadata {
     fn eq(&self, other: &Self) -> bool {
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs
index daec9303b2c6..129e336c7e43 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs
@@ -99,7 +99,7 @@ const SINGLE_VARIANT_VIRTUAL_DISR: u64 = 0;
 /// compiler versions.
 ///
 /// Niche-tag enums have one special variant, usually called the
-/// "dataful variant". This variant has a field that
+/// "untagged variant". This variant has a field that
 /// doubles as the tag of the enum. The variant is active when the value of
 /// that field is within a pre-defined range. Therefore the variant struct
 /// has a `DISCR_BEGIN` and `DISCR_END` field instead of `DISCR_EXACT` in
@@ -249,7 +249,7 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
                     None,
                 ),
                 Variants::Multiple {
-                    tag_encoding: TagEncoding::Niche { dataful_variant, .. },
+                    tag_encoding: TagEncoding::Niche { untagged_variant, .. },
                     ref variants,
                     tag_field,
                     ..
@@ -260,7 +260,7 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
                     enum_type_di_node,
                     variants.indices(),
                     tag_field,
-                    Some(dataful_variant),
+                    Some(untagged_variant),
                 ),
             }
         },
@@ -391,7 +391,7 @@ fn build_union_fields_for_enum<'ll, 'tcx>(
     enum_type_di_node: &'ll DIType,
     variant_indices: impl Iterator<Item = VariantIdx> + Clone,
     tag_field: usize,
-    dataful_variant_index: Option<VariantIdx>,
+    untagged_variant_index: Option<VariantIdx>,
 ) -> SmallVec<&'ll DIType> {
     let tag_base_type = super::tag_base_type(cx, enum_type_and_layout);
 
@@ -436,7 +436,7 @@ fn build_union_fields_for_enum<'ll, 'tcx>(
         variant_names_type_di_node,
         tag_base_type,
         tag_field,
-        dataful_variant_index,
+        untagged_variant_index,
     )
 }
 
@@ -472,7 +472,7 @@ fn build_variant_struct_wrapper_type_di_node<'ll, 'tcx>(
     enum_or_generator_type_and_layout: TyAndLayout<'tcx>,
     enum_or_generator_type_di_node: &'ll DIType,
     variant_index: VariantIdx,
-    dataful_variant_index: Option<VariantIdx>,
+    untagged_variant_index: Option<VariantIdx>,
     variant_struct_type_di_node: &'ll DIType,
     variant_names_type_di_node: &'ll DIType,
     tag_base_type_di_node: &'ll DIType,
@@ -517,7 +517,7 @@ fn build_variant_struct_wrapper_type_di_node<'ll, 'tcx>(
                     }
                 }
                 DiscrResult::Range(min, max) => {
-                    assert_eq!(Some(variant_index), dataful_variant_index);
+                    assert_eq!(Some(variant_index), untagged_variant_index);
                     if is_128_bits {
                         DiscrKind::Range128(min, max)
                     } else {
@@ -757,7 +757,7 @@ fn build_union_fields_for_direct_tag_enum_or_generator<'ll, 'tcx>(
     discr_type_di_node: &'ll DIType,
     tag_base_type: Ty<'tcx>,
     tag_field: usize,
-    dataful_variant_index: Option<VariantIdx>,
+    untagged_variant_index: Option<VariantIdx>,
 ) -> SmallVec<&'ll DIType> {
     let tag_base_type_di_node = type_di_node(cx, tag_base_type);
     let mut unions_fields = SmallVec::with_capacity(variant_field_infos.len() + 1);
@@ -776,7 +776,7 @@ fn build_union_fields_for_direct_tag_enum_or_generator<'ll, 'tcx>(
             enum_type_and_layout,
             enum_type_di_node,
             variant_member_info.variant_index,
-            dataful_variant_index,
+            untagged_variant_index,
             variant_member_info.variant_struct_type_di_node,
             discr_type_di_node,
             tag_base_type_di_node,
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
index 9b3d080bfd6a..14044d0f99b9 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
@@ -417,7 +417,7 @@ impl DiscrResult {
 /// Returns the discriminant value corresponding to the variant index.
 ///
 /// Will return `None` if there is less than two variants (because then the enum won't have)
-/// a tag, and if this is the dataful variant of a niche-layout enum (because then there is no
+/// a tag, and if this is the untagged variant of a niche-layout enum (because then there is no
 /// single discriminant value).
 fn compute_discriminant_value<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
@@ -430,11 +430,11 @@ fn compute_discriminant_value<'ll, 'tcx>(
             enum_type_and_layout.ty.discriminant_for_variant(cx.tcx, variant_index).unwrap().val,
         ),
         &Variants::Multiple {
-            tag_encoding: TagEncoding::Niche { ref niche_variants, niche_start, dataful_variant },
+            tag_encoding: TagEncoding::Niche { ref niche_variants, niche_start, untagged_variant },
             tag,
             ..
         } => {
-            if variant_index == dataful_variant {
+            if variant_index == untagged_variant {
                 let valid_range = enum_type_and_layout
                     .for_variant(cx, variant_index)
                     .largest_niche
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs
index dae90a43f265..becbccc434d9 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs
@@ -378,7 +378,7 @@ fn build_discr_member_di_node<'ll, 'tcx>(
 ///
 /// The DW_AT_discr_value is optional, and is omitted if
 ///   - This is the only variant of a univariant enum (i.e. their is no discriminant)
-///   - This is the "dataful" variant of a niche-layout enum
+///   - This is the "untagged" variant of a niche-layout enum
 ///     (where only the other variants are identified by a single value)
 ///
 /// There is only ever a single member, the type of which is a struct that describes the
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index cf591295b846..b23fe3fc9d55 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -39,7 +39,6 @@ use smallvec::SmallVec;
 use std::cell::OnceCell;
 use std::cell::RefCell;
 use std::iter;
-use tracing::debug;
 
 mod create_scope_map;
 pub mod gdb;
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs b/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
index 8f2436739077..a40cfc8b23fb 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
@@ -6,7 +6,7 @@ use super::CodegenUnitDebugContext;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::layout::{HasParamEnv, LayoutOf};
 use rustc_middle::ty::{self, DefIdTree, Ty};
-use tracing::trace;
+use trace;
 
 use crate::common::CodegenCx;
 use crate::llvm;
diff --git a/compiler/rustc_codegen_llvm/src/declare.rs b/compiler/rustc_codegen_llvm/src/declare.rs
index fa0ecd18fc89..0f663a26732b 100644
--- a/compiler/rustc_codegen_llvm/src/declare.rs
+++ b/compiler/rustc_codegen_llvm/src/declare.rs
@@ -22,7 +22,6 @@ use rustc_codegen_ssa::traits::TypeMembershipMethods;
 use rustc_middle::ty::Ty;
 use rustc_symbol_mangling::typeid::typeid_for_fnabi;
 use smallvec::SmallVec;
-use tracing::debug;
 
 /// Declare a function.
 ///
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 3d789904707c..a640de42a6a8 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -1705,6 +1705,97 @@ unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
     bitwise_red!(simd_reduce_all: vector_reduce_and, true);
     bitwise_red!(simd_reduce_any: vector_reduce_or, true);
 
+    if name == sym::simd_cast_ptr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::RawPtr(p) => {
+                let (metadata, check_sized) = p.ty.ptr_metadata_ty(bx.tcx, |ty| {
+                    bx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), ty)
+                });
+                assert!(!check_sized); // we are in codegen, so we shouldn't see these types
+                require!(metadata.is_unit(), "cannot cast fat pointer `{}`", in_elem)
+            }
+            _ => return_error!("expected pointer, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::RawPtr(p) => {
+                let (metadata, check_sized) = p.ty.ptr_metadata_ty(bx.tcx, |ty| {
+                    bx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), ty)
+                });
+                assert!(!check_sized); // we are in codegen, so we shouldn't see these types
+                require!(metadata.is_unit(), "cannot cast to fat pointer `{}`", out_elem)
+            }
+            _ => return_error!("expected pointer, got `{}`", out_elem),
+        }
+
+        if in_elem == out_elem {
+            return Ok(args[0].immediate());
+        } else {
+            return Ok(bx.pointercast(args[0].immediate(), llret_ty));
+        }
+    }
+
+    if name == sym::simd_expose_addr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::RawPtr(_) => {}
+            _ => return_error!("expected pointer, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::Uint(ty::UintTy::Usize) => {}
+            _ => return_error!("expected `usize`, got `{}`", out_elem),
+        }
+
+        return Ok(bx.ptrtoint(args[0].immediate(), llret_ty));
+    }
+
+    if name == sym::simd_from_exposed_addr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::Uint(ty::UintTy::Usize) => {}
+            _ => return_error!("expected `usize`, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::RawPtr(_) => {}
+            _ => return_error!("expected pointer, got `{}`", out_elem),
+        }
+
+        return Ok(bx.inttoptr(args[0].immediate(), llret_ty));
+    }
+
     if name == sym::simd_cast || name == sym::simd_as {
         require_simd!(ret_ty, "return");
         let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index 636d689a34b5..15bfa8430460 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -7,7 +7,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(hash_raw_entry)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(extern_types)]
 #![feature(once_cell)]
 #![feature(iter_intersperse)]
@@ -16,6 +15,8 @@
 
 #[macro_use]
 extern crate rustc_macros;
+#[macro_use]
+extern crate tracing;
 
 use back::write::{create_informational_target_machine, create_target_machine};
 
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 172684414fc5..42cb694c0e75 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -400,27 +400,6 @@ impl AtomicOrdering {
     }
 }
 
-/// LLVMRustSynchronizationScope
-#[derive(Copy, Clone)]
-#[repr(C)]
-pub enum SynchronizationScope {
-    SingleThread,
-    CrossThread,
-}
-
-impl SynchronizationScope {
-    pub fn from_generic(sc: rustc_codegen_ssa::common::SynchronizationScope) -> Self {
-        match sc {
-            rustc_codegen_ssa::common::SynchronizationScope::SingleThread => {
-                SynchronizationScope::SingleThread
-            }
-            rustc_codegen_ssa::common::SynchronizationScope::CrossThread => {
-                SynchronizationScope::CrossThread
-            }
-        }
-    }
-}
-
 /// LLVMRustFileType
 #[derive(Copy, Clone)]
 #[repr(C)]
@@ -1096,7 +1075,7 @@ extern "C" {
     pub fn LLVMConstInt(IntTy: &Type, N: c_ulonglong, SignExtend: Bool) -> &Value;
     pub fn LLVMConstIntOfArbitraryPrecision(IntTy: &Type, Wn: c_uint, Ws: *const u64) -> &Value;
     pub fn LLVMConstReal(RealTy: &Type, N: f64) -> &Value;
-    pub fn LLVMConstIntGetZExtValue(ConstantVal: &ConstantInt) -> c_ulonglong;
+    pub fn LLVMRustConstIntGetZExtValue(ConstantVal: &ConstantInt, Value: &mut u64) -> bool;
     pub fn LLVMRustConstInt128Get(
         ConstantVal: &ConstantInt,
         SExt: bool,
@@ -1782,16 +1761,18 @@ extern "C" {
         Order: AtomicOrdering,
     ) -> &'a Value;
 
-    pub fn LLVMRustBuildAtomicCmpXchg<'a>(
+    pub fn LLVMBuildAtomicCmpXchg<'a>(
         B: &Builder<'a>,
         LHS: &'a Value,
         CMP: &'a Value,
         RHS: &'a Value,
         Order: AtomicOrdering,
         FailureOrder: AtomicOrdering,
-        Weak: Bool,
+        SingleThreaded: Bool,
     ) -> &'a Value;
 
+    pub fn LLVMSetWeak(CmpXchgInst: &Value, IsWeak: Bool);
+
     pub fn LLVMBuildAtomicRMW<'a>(
         B: &Builder<'a>,
         Op: AtomicRmwBinOp,
@@ -1801,27 +1782,19 @@ extern "C" {
         SingleThreaded: Bool,
     ) -> &'a Value;
 
-    pub fn LLVMRustBuildAtomicFence(
-        B: &Builder<'_>,
+    pub fn LLVMBuildFence<'a>(
+        B: &Builder<'a>,
         Order: AtomicOrdering,
-        Scope: SynchronizationScope,
-    );
+        SingleThreaded: Bool,
+        Name: *const c_char,
+    ) -> &'a Value;
 
     /// Writes a module to the specified path. Returns 0 on success.
     pub fn LLVMWriteBitcodeToFile(M: &Module, Path: *const c_char) -> c_int;
 
-    /// Creates a pass manager.
+    /// Creates a legacy pass manager -- only used for final codegen.
     pub fn LLVMCreatePassManager<'a>() -> &'a mut PassManager<'a>;
 
-    /// Creates a function-by-function pass manager
-    pub fn LLVMCreateFunctionPassManagerForModule(M: &Module) -> &mut PassManager<'_>;
-
-    /// Disposes a pass manager.
-    pub fn LLVMDisposePassManager<'a>(PM: &'a mut PassManager<'a>);
-
-    /// Runs a pass manager on a module.
-    pub fn LLVMRunPassManager<'a>(PM: &PassManager<'a>, M: &'a Module) -> Bool;
-
     pub fn LLVMInitializePasses();
 
     pub fn LLVMTimeTraceProfilerInitialize();
@@ -1832,32 +1805,6 @@ extern "C" {
 
     pub fn LLVMAddAnalysisPasses<'a>(T: &'a TargetMachine, PM: &PassManager<'a>);
 
-    pub fn LLVMRustPassManagerBuilderCreate() -> &'static mut PassManagerBuilder;
-    pub fn LLVMRustPassManagerBuilderDispose(PMB: &'static mut PassManagerBuilder);
-    pub fn LLVMRustPassManagerBuilderUseInlinerWithThreshold(
-        PMB: &PassManagerBuilder,
-        threshold: c_uint,
-    );
-    pub fn LLVMRustPassManagerBuilderPopulateModulePassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-    );
-
-    pub fn LLVMRustPassManagerBuilderPopulateFunctionPassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-    );
-    pub fn LLVMRustPassManagerBuilderPopulateLTOPassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-        Internalize: Bool,
-        RunInliner: Bool,
-    );
-    pub fn LLVMRustPassManagerBuilderPopulateThinLTOPassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-    );
-
     pub fn LLVMGetHostCPUFeatures() -> *mut c_char;
 
     pub fn LLVMDisposeMessage(message: *mut c_char);
@@ -2262,22 +2209,6 @@ extern "C" {
 
     pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&ConstantInt>;
 
-    pub fn LLVMRustFindAndCreatePass(Pass: *const c_char) -> Option<&'static mut Pass>;
-    pub fn LLVMRustCreateAddressSanitizerFunctionPass(Recover: bool) -> &'static mut Pass;
-    pub fn LLVMRustCreateModuleAddressSanitizerPass(Recover: bool) -> &'static mut Pass;
-    pub fn LLVMRustCreateMemorySanitizerPass(
-        TrackOrigins: c_int,
-        Recover: bool,
-    ) -> &'static mut Pass;
-    pub fn LLVMRustCreateThreadSanitizerPass() -> &'static mut Pass;
-    pub fn LLVMRustCreateHWAddressSanitizerPass(Recover: bool) -> &'static mut Pass;
-    pub fn LLVMRustAddPass(PM: &PassManager<'_>, Pass: &'static mut Pass);
-    pub fn LLVMRustAddLastExtensionPasses(
-        PMB: &PassManagerBuilder,
-        Passes: *const &'static mut Pass,
-        NumPasses: size_t,
-    );
-
     pub fn LLVMRustHasFeature(T: &TargetMachine, s: *const c_char) -> bool;
 
     pub fn LLVMRustPrintTargetCPUs(T: &TargetMachine);
@@ -2311,29 +2242,11 @@ extern "C" {
         SplitDwarfFile: *const c_char,
     ) -> Option<&'static mut TargetMachine>;
     pub fn LLVMRustDisposeTargetMachine(T: &'static mut TargetMachine);
-    pub fn LLVMRustAddBuilderLibraryInfo<'a>(
-        PMB: &'a PassManagerBuilder,
-        M: &'a Module,
-        DisableSimplifyLibCalls: bool,
-    );
-    pub fn LLVMRustConfigurePassManagerBuilder(
-        PMB: &PassManagerBuilder,
-        OptLevel: CodeGenOptLevel,
-        MergeFunctions: bool,
-        SLPVectorize: bool,
-        LoopVectorize: bool,
-        PrepareForThinLTO: bool,
-        PGOGenPath: *const c_char,
-        PGOUsePath: *const c_char,
-        PGOSampleUsePath: *const c_char,
-        SizeLevel: c_int,
-    );
     pub fn LLVMRustAddLibraryInfo<'a>(
         PM: &PassManager<'a>,
         M: &'a Module,
         DisableSimplifyLibCalls: bool,
     );
-    pub fn LLVMRustRunFunctionPassManager<'a>(PM: &PassManager<'a>, M: &'a Module);
     pub fn LLVMRustWriteOutputFile<'a>(
         T: &'a TargetMachine,
         PM: &PassManager<'a>,
@@ -2342,7 +2255,7 @@ extern "C" {
         DwoOutput: *const c_char,
         FileType: FileType,
     ) -> LLVMRustResult;
-    pub fn LLVMRustOptimizeWithNewPassManager<'a>(
+    pub fn LLVMRustOptimize<'a>(
         M: &'a Module,
         TM: &'a TargetMachine,
         OptLevel: PassBuilderOptLevel,
@@ -2380,7 +2293,6 @@ extern "C" {
     pub fn LLVMRustSetLLVMOptions(Argc: c_int, Argv: *const *const c_char);
     pub fn LLVMRustPrintPasses();
     pub fn LLVMRustSetNormalizedTarget(M: &Module, triple: *const c_char);
-    pub fn LLVMRustAddAlwaysInlinePass(P: &PassManagerBuilder, AddLifetimes: bool);
     pub fn LLVMRustRunRestrictionPass(M: &Module, syms: *const *const c_char, len: size_t);
 
     pub fn LLVMRustOpenArchive(path: *const c_char) -> Option<&'static mut Archive>;
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index f5d676c44e34..2fd58567c487 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -1,7 +1,6 @@
 use crate::back::write::create_informational_target_machine;
-use crate::{llvm, llvm_util};
+use crate::llvm;
 use libc::c_int;
-use libloading::Library;
 use rustc_codegen_ssa::target_features::{
     supported_target_features, tied_target_features, RUSTC_SPECIFIC_FEATURES,
 };
@@ -15,9 +14,7 @@ use rustc_span::symbol::Symbol;
 use rustc_target::spec::{MergeFunctions, PanicStrategy};
 use smallvec::{smallvec, SmallVec};
 use std::ffi::{CStr, CString};
-use tracing::debug;
 
-use std::mem;
 use std::path::Path;
 use std::ptr;
 use std::slice;
@@ -121,22 +118,6 @@ unsafe fn configure_llvm(sess: &Session) {
 
     llvm::LLVMInitializePasses();
 
-    // Use the legacy plugin registration if we don't use the new pass manager
-    if !should_use_new_llvm_pass_manager(
-        &sess.opts.unstable_opts.new_llvm_pass_manager,
-        &sess.target.arch,
-    ) {
-        // Register LLVM plugins by loading them into the compiler process.
-        for plugin in &sess.opts.unstable_opts.llvm_plugins {
-            let lib = Library::new(plugin).unwrap_or_else(|e| bug!("couldn't load plugin: {}", e));
-            debug!("LLVM plugin loaded successfully {:?} ({})", lib, plugin);
-
-            // Intentionally leak the dynamic library. We can't ever unload it
-            // since the library can make things that will live arbitrarily long.
-            mem::forget(lib);
-        }
-    }
-
     rustc_llvm::initialize_available_targets();
 
     llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int, llvm_args.as_ptr());
@@ -155,6 +136,10 @@ pub fn time_trace_profiler_finish(file_name: &Path) {
 //
 // To find a list of LLVM's names, check llvm-project/llvm/include/llvm/Support/*TargetParser.def
 // where the * matches the architecture's name
+//
+// For targets not present in the above location, see llvm-project/llvm/lib/Target/{ARCH}/*.td
+// where `{ARCH}` is the architecture name. Look for instances of `SubtargetFeature`.
+//
 // Beware to not use the llvm github project for this, but check the git submodule
 // found in src/llvm-project
 // Though note that Rust can also be build with an external precompiled version of LLVM
@@ -536,19 +521,3 @@ pub fn tune_cpu(sess: &Session) -> Option<&str> {
     let name = sess.opts.unstable_opts.tune_cpu.as_ref()?;
     Some(handle_native(name))
 }
-
-pub(crate) fn should_use_new_llvm_pass_manager(user_opt: &Option<bool>, target_arch: &str) -> bool {
-    // The new pass manager is enabled by default for LLVM >= 13.
-    // This matches Clang, which also enables it since Clang 13.
-
-    // Since LLVM 15, the legacy pass manager is no longer supported.
-    if llvm_util::get_version() >= (15, 0, 0) {
-        return true;
-    }
-
-    // There are some perf issues with the new pass manager when targeting
-    // s390x with LLVM 13, so enable the new pass manager only with LLVM 14.
-    // See https://github.com/rust-lang/rust/issues/89609.
-    let min_version = if target_arch == "s390x" { 14 } else { 13 };
-    user_opt.unwrap_or_else(|| llvm_util::get_version() >= (min_version, 0, 0))
-}
diff --git a/compiler/rustc_codegen_llvm/src/mono_item.rs b/compiler/rustc_codegen_llvm/src/mono_item.rs
index 6e94284852f3..1eceb7f5c87b 100644
--- a/compiler/rustc_codegen_llvm/src/mono_item.rs
+++ b/compiler/rustc_codegen_llvm/src/mono_item.rs
@@ -11,7 +11,6 @@ use rustc_middle::ty::layout::{FnAbiOf, LayoutOf};
 use rustc_middle::ty::{self, Instance, TypeVisitable};
 use rustc_session::config::CrateType;
 use rustc_target::spec::RelocModel;
-use tracing::debug;
 
 impl<'tcx> PreDefineMethods<'tcx> for CodegenCx<'_, 'tcx> {
     fn predefine_static(
diff --git a/compiler/rustc_codegen_llvm/src/type_of.rs b/compiler/rustc_codegen_llvm/src/type_of.rs
index 9f0e6c80b19a..dc1165835e7c 100644
--- a/compiler/rustc_codegen_llvm/src/type_of.rs
+++ b/compiler/rustc_codegen_llvm/src/type_of.rs
@@ -11,7 +11,6 @@ use rustc_target::abi::{Abi, AddressSpace, Align, FieldsShape};
 use rustc_target::abi::{Int, Pointer, F32, F64};
 use rustc_target::abi::{PointeeInfo, Scalar, Size, TyAbiInterface, Variants};
 use smallvec::{smallvec, SmallVec};
-use tracing::debug;
 
 use std::fmt::Write;
 
diff --git a/compiler/rustc_codegen_ssa/src/back/archive.rs b/compiler/rustc_codegen_ssa/src/back/archive.rs
index 0d2aa483d3d4..bad58d0a8a0a 100644
--- a/compiler/rustc_codegen_ssa/src/back/archive.rs
+++ b/compiler/rustc_codegen_ssa/src/back/archive.rs
@@ -1,44 +1,16 @@
+use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::memmap::Mmap;
 use rustc_session::cstore::DllImport;
 use rustc_session::Session;
+use rustc_span::symbol::Symbol;
 
+use object::read::archive::ArchiveFile;
+
+use std::fmt::Display;
+use std::fs::File;
 use std::io;
 use std::path::{Path, PathBuf};
 
-pub(super) fn find_library(
-    name: &str,
-    verbatim: bool,
-    search_paths: &[PathBuf],
-    sess: &Session,
-) -> PathBuf {
-    // On Windows, static libraries sometimes show up as libfoo.a and other
-    // times show up as foo.lib
-    let oslibname = if verbatim {
-        name.to_string()
-    } else {
-        format!("{}{}{}", sess.target.staticlib_prefix, name, sess.target.staticlib_suffix)
-    };
-    let unixlibname = format!("lib{}.a", name);
-
-    for path in search_paths {
-        debug!("looking for {} inside {:?}", name, path);
-        let test = path.join(&oslibname);
-        if test.exists() {
-            return test;
-        }
-        if oslibname != unixlibname {
-            let test = path.join(&unixlibname);
-            if test.exists() {
-                return test;
-            }
-        }
-    }
-    sess.fatal(&format!(
-        "could not find native static library `{}`, \
-                         perhaps an -L flag is missing?",
-        name
-    ));
-}
-
 pub trait ArchiveBuilderBuilder {
     fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder<'a> + 'a>;
 
@@ -54,6 +26,36 @@ pub trait ArchiveBuilderBuilder {
         dll_imports: &[DllImport],
         tmpdir: &Path,
     ) -> PathBuf;
+
+    fn extract_bundled_libs(
+        &self,
+        rlib: &Path,
+        outdir: &Path,
+        bundled_lib_file_names: &FxHashSet<Symbol>,
+    ) -> Result<(), String> {
+        let message = |msg: &str, e: &dyn Display| format!("{} '{}': {}", msg, &rlib.display(), e);
+        let archive_map = unsafe {
+            Mmap::map(File::open(rlib).map_err(|e| message("failed to open file", &e))?)
+                .map_err(|e| message("failed to mmap file", &e))?
+        };
+        let archive = ArchiveFile::parse(&*archive_map)
+            .map_err(|e| message("failed to parse archive", &e))?;
+
+        for entry in archive.members() {
+            let entry = entry.map_err(|e| message("failed to read entry", &e))?;
+            let data = entry
+                .data(&*archive_map)
+                .map_err(|e| message("failed to get data from archive member", &e))?;
+            let name = std::str::from_utf8(entry.name())
+                .map_err(|e| message("failed to convert name", &e))?;
+            if !bundled_lib_file_names.contains(&Symbol::intern(name)) {
+                continue; // We need to extract only native libraries.
+            }
+            std::fs::write(&outdir.join(&name), data)
+                .map_err(|e| message("failed to write file", &e))?;
+        }
+        Ok(())
+    }
 }
 
 pub trait ArchiveBuilder<'a> {
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index d2f2c7bf7988..bb57fca74a21 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -1,11 +1,13 @@
 use rustc_arena::TypedArena;
 use rustc_ast::CRATE_NODE_ID;
-use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
+use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::temp_dir::MaybeTempDir;
 use rustc_errors::{ErrorGuaranteed, Handler};
 use rustc_fs_util::fix_windows_verbatim_for_gcc;
 use rustc_hir::def_id::CrateNum;
+use rustc_metadata::find_native_static_library;
 use rustc_metadata::fs::{emit_metadata, METADATA_FILENAME};
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::SymbolExportKind;
@@ -24,7 +26,7 @@ use rustc_target::spec::crt_objects::{CrtObjects, LinkSelfContainedDefault};
 use rustc_target::spec::{LinkOutputKind, LinkerFlavor, LldFlavor, SplitDebuginfo};
 use rustc_target::spec::{PanicStrategy, RelocModel, RelroLevel, SanitizerSet, Target};
 
-use super::archive::{find_library, ArchiveBuilder, ArchiveBuilderBuilder};
+use super::archive::{ArchiveBuilder, ArchiveBuilderBuilder};
 use super::command::Command;
 use super::linker::{self, Linker};
 use super::metadata::{create_rmeta_file, MetadataPosition};
@@ -44,7 +46,7 @@ use std::io::{BufWriter, Write};
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
 use std::process::{ExitStatus, Output, Stdio};
-use std::{ascii, char, env, fmt, fs, io, mem, str};
+use std::{env, fmt, fs, io, mem, str};
 
 pub fn ensure_removed(diag_handler: &Handler, path: &Path) {
     if let Err(e) = fs::remove_file(path) {
@@ -307,6 +309,9 @@ fn link_rlib<'a>(
         }
     }
 
+    // Used if packed_bundled_libs flag enabled.
+    let mut packed_bundled_libs = Vec::new();
+
     // Note that in this loop we are ignoring the value of `lib.cfg`. That is,
     // we may not be configured to actually include a static library if we're
     // adding it here. That's because later when we consume this rlib we'll
@@ -325,6 +330,8 @@ fn link_rlib<'a>(
     // metadata of the rlib we're generating somehow.
     for lib in codegen_results.crate_info.used_libraries.iter() {
         match lib.kind {
+            NativeLibKind::Static { bundle: None | Some(true), whole_archive: Some(true) }
+                if flavor == RlibFlavor::Normal && sess.opts.unstable_opts.packed_bundled_libs => {}
             NativeLibKind::Static { bundle: None | Some(true), whole_archive: Some(true) }
                 if flavor == RlibFlavor::Normal =>
             {
@@ -348,7 +355,16 @@ fn link_rlib<'a>(
         }
         if let Some(name) = lib.name {
             let location =
-                find_library(name.as_str(), lib.verbatim.unwrap_or(false), &lib_search_paths, sess);
+                find_native_static_library(name.as_str(), lib.verbatim, &lib_search_paths, sess);
+            if sess.opts.unstable_opts.packed_bundled_libs && flavor == RlibFlavor::Normal {
+                packed_bundled_libs.push(find_native_static_library(
+                    lib.filename.unwrap().as_str(),
+                    Some(true),
+                    &lib_search_paths,
+                    sess,
+                ));
+                continue;
+            }
             ab.add_archive(&location, Box::new(|_| false)).unwrap_or_else(|e| {
                 sess.fatal(&format!(
                     "failed to add native library {}: {}",
@@ -403,6 +419,12 @@ fn link_rlib<'a>(
         ab.add_file(&trailing_metadata);
     }
 
+    // Add all bundled static native library dependencies.
+    // Archives added to the end of .rlib archive, see comment above for the reason.
+    for lib in packed_bundled_libs {
+        ab.add_file(&lib)
+    }
+
     return Ok(ab);
 }
 
@@ -552,14 +574,6 @@ fn link_staticlib<'a>(
     Ok(())
 }
 
-fn escape_stdout_stderr_string(s: &[u8]) -> String {
-    str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
-        let mut x = "Non-UTF-8 output: ".to_string();
-        x.extend(s.iter().flat_map(|&b| ascii::escape_default(b)).map(char::from));
-        x
-    })
-}
-
 /// Use `thorin` (rust implementation of a dwarf packaging utility) to link DWARF objects into a
 /// DWARF package.
 fn link_dwarf_object<'a>(
@@ -866,7 +880,7 @@ fn link_natively<'a>(
             if !prog.status.success() {
                 let mut output = prog.stderr.clone();
                 output.extend_from_slice(&prog.stdout);
-                let escaped_output = escape_stdout_stderr_string(&output);
+                let escaped_output = escape_string(&output);
                 let mut err = sess.struct_err(&format!(
                     "linking with `{}` failed: {}",
                     linker_path.display(),
@@ -934,8 +948,8 @@ fn link_natively<'a>(
 
                 sess.abort_if_errors();
             }
-            info!("linker stderr:\n{}", escape_stdout_stderr_string(&prog.stderr));
-            info!("linker stdout:\n{}", escape_stdout_stderr_string(&prog.stdout));
+            info!("linker stderr:\n{}", escape_string(&prog.stderr));
+            info!("linker stdout:\n{}", escape_string(&prog.stdout));
         }
         Err(e) => {
             let linker_not_found = e.kind() == io::ErrorKind::NotFound;
@@ -1065,11 +1079,10 @@ fn strip_symbols_in_osx<'a>(sess: &'a Session, out_filename: &Path, option: Opti
 }
 
 fn escape_string(s: &[u8]) -> String {
-    str::from_utf8(s).map(|s| s.to_owned()).unwrap_or_else(|_| {
-        let mut x = "Non-UTF-8 output: ".to_string();
-        x.extend(s.iter().flat_map(|&b| ascii::escape_default(b)).map(char::from));
-        x
-    })
+    match str::from_utf8(s) {
+        Ok(s) => s.to_owned(),
+        Err(_) => format!("Non-UTF-8 output: {}", s.escape_ascii()),
+    }
 }
 
 fn add_sanitizer_libraries(sess: &Session, crate_type: CrateType, linker: &mut dyn Linker) {
@@ -1077,11 +1090,12 @@ fn add_sanitizer_libraries(sess: &Session, crate_type: CrateType, linker: &mut d
     // both executables and dynamic shared objects. Everywhere else the runtimes
     // are currently distributed as static libraries which should be linked to
     // executables only.
-    let needs_runtime = match crate_type {
-        CrateType::Executable => true,
-        CrateType::Dylib | CrateType::Cdylib | CrateType::ProcMacro => sess.target.is_like_osx,
-        CrateType::Rlib | CrateType::Staticlib => false,
-    };
+    let needs_runtime = !sess.target.is_like_android
+        && match crate_type {
+            CrateType::Executable => true,
+            CrateType::Dylib | CrateType::Cdylib | CrateType::ProcMacro => sess.target.is_like_osx,
+            CrateType::Rlib | CrateType::Staticlib => false,
+        };
 
     if !needs_runtime {
         return;
@@ -1173,13 +1187,6 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
             // only the linker flavor is known; use the default linker for the selected flavor
             (None, Some(flavor)) => Some((
                 PathBuf::from(match flavor {
-                    LinkerFlavor::Em => {
-                        if cfg!(windows) {
-                            "emcc.bat"
-                        } else {
-                            "emcc"
-                        }
-                    }
                     LinkerFlavor::Gcc => {
                         if cfg!(any(target_os = "solaris", target_os = "illumos")) {
                             // On historical Solaris systems, "cc" may have
@@ -1194,11 +1201,17 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
                         }
                     }
                     LinkerFlavor::Ld => "ld",
-                    LinkerFlavor::Msvc => "link.exe",
                     LinkerFlavor::Lld(_) => "lld",
-                    LinkerFlavor::PtxLinker => "rust-ptx-linker",
-                    LinkerFlavor::BpfLinker => "bpf-linker",
-                    LinkerFlavor::L4Bender => "l4-bender",
+                    LinkerFlavor::Msvc => "link.exe",
+                    LinkerFlavor::EmCc => {
+                        if cfg!(windows) {
+                            "emcc.bat"
+                        } else {
+                            "emcc"
+                        }
+                    }
+                    LinkerFlavor::Bpf => "bpf-linker",
+                    LinkerFlavor::Ptx => "rust-ptx-linker",
                 }),
                 flavor,
             )),
@@ -1208,7 +1221,7 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
                 });
 
                 let flavor = if stem == "emcc" {
-                    LinkerFlavor::Em
+                    LinkerFlavor::EmCc
                 } else if stem == "gcc"
                     || stem.ends_with("-gcc")
                     || stem == "clang"
@@ -1236,7 +1249,8 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
 
     // linker and linker flavor specified via command line have precedence over what the target
     // specification specifies
-    if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), sess.opts.cg.linker_flavor) {
+    let linker_flavor = sess.opts.cg.linker_flavor.map(LinkerFlavor::from_cli);
+    if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), linker_flavor) {
         return ret;
     }
 
@@ -1714,6 +1728,13 @@ fn add_post_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor
 /// that are necessary for the linking. They are only present in symbol table but not actually
 /// used in any sections, so the linker will therefore pick relevant rlibs for linking, but
 /// unused `#[no_mangle]` or `#[used]` can still be discard by GC sections.
+///
+/// There's a few internal crates in the standard library (aka libcore and
+/// libstd) which actually have a circular dependence upon one another. This
+/// currently arises through "weak lang items" where libcore requires things
+/// like `rust_begin_unwind` but libstd ends up defining it. To get this
+/// circular dependence to work correctly we declare some of these things
+/// in this synthetic object.
 fn add_linked_symbol_object(
     cmd: &mut dyn Linker,
     sess: &Session,
@@ -2113,11 +2134,11 @@ fn add_order_independent_options(
         });
     }
 
-    if flavor == LinkerFlavor::PtxLinker {
+    if flavor == LinkerFlavor::Ptx {
         // Provide the linker with fallback to internal `target-cpu`.
         cmd.arg("--fallback-arch");
         cmd.arg(&codegen_results.crate_info.target_cpu);
-    } else if flavor == LinkerFlavor::BpfLinker {
+    } else if flavor == LinkerFlavor::Bpf {
         cmd.arg("--cpu");
         cmd.arg(&codegen_results.crate_info.target_cpu);
         cmd.arg("--cpu-features");
@@ -2333,72 +2354,25 @@ fn add_upstream_rust_crates<'a>(
     // crates.
     let deps = &codegen_results.crate_info.used_crates;
 
-    // There's a few internal crates in the standard library (aka libcore and
-    // libstd) which actually have a circular dependence upon one another. This
-    // currently arises through "weak lang items" where libcore requires things
-    // like `rust_begin_unwind` but libstd ends up defining it. To get this
-    // circular dependence to work correctly in all situations we'll need to be
-    // sure to correctly apply the `--start-group` and `--end-group` options to
-    // GNU linkers, otherwise if we don't use any other symbol from the standard
-    // library it'll get discarded and the whole application won't link.
-    //
-    // In this loop we're calculating the `group_end`, after which crate to
-    // pass `--end-group` and `group_start`, before which crate to pass
-    // `--start-group`. We currently do this by passing `--end-group` after
-    // the first crate (when iterating backwards) that requires a lang item
-    // defined somewhere else. Once that's set then when we've defined all the
-    // necessary lang items we'll pass `--start-group`.
-    //
-    // Note that this isn't amazing logic for now but it should do the trick
-    // for the current implementation of the standard library.
-    let mut group_end = None;
-    let mut group_start = None;
-    // Crates available for linking thus far.
-    let mut available = FxHashSet::default();
-    // Crates required to satisfy dependencies discovered so far.
-    let mut required = FxHashSet::default();
-
-    let info = &codegen_results.crate_info;
-    for &cnum in deps.iter().rev() {
-        if let Some(missing) = info.missing_lang_items.get(&cnum) {
-            let missing_crates = missing.iter().map(|i| info.lang_item_to_crate.get(i).copied());
-            required.extend(missing_crates);
-        }
-
-        required.insert(Some(cnum));
-        available.insert(Some(cnum));
-
-        if required.len() > available.len() && group_end.is_none() {
-            group_end = Some(cnum);
-        }
-        if required.len() == available.len() && group_end.is_some() {
-            group_start = Some(cnum);
-            break;
-        }
-    }
-
-    // If we didn't end up filling in all lang items from upstream crates then
-    // we'll be filling it in with our crate. This probably means we're the
-    // standard library itself, so skip this for now.
-    if group_end.is_some() && group_start.is_none() {
-        group_end = None;
-    }
-
     let mut compiler_builtins = None;
     let search_path = OnceCell::new();
 
     for &cnum in deps.iter() {
-        if group_start == Some(cnum) {
-            cmd.group_start();
-        }
-
         // We may not pass all crates through to the linker. Some crates may
         // appear statically in an existing dylib, meaning we'll pick up all the
         // symbols from the dylib.
         let src = &codegen_results.crate_info.used_crate_source[&cnum];
         match data[cnum.as_usize() - 1] {
             _ if codegen_results.crate_info.profiler_runtime == Some(cnum) => {
-                add_static_crate(cmd, sess, archive_builder_builder, codegen_results, tmpdir, cnum);
+                add_static_crate(
+                    cmd,
+                    sess,
+                    archive_builder_builder,
+                    codegen_results,
+                    tmpdir,
+                    cnum,
+                    &Default::default(),
+                );
             }
             // compiler-builtins are always placed last to ensure that they're
             // linked correctly.
@@ -2408,7 +2382,23 @@ fn add_upstream_rust_crates<'a>(
             }
             Linkage::NotLinked | Linkage::IncludedFromDylib => {}
             Linkage::Static => {
-                add_static_crate(cmd, sess, archive_builder_builder, codegen_results, tmpdir, cnum);
+                let bundled_libs = if sess.opts.unstable_opts.packed_bundled_libs {
+                    codegen_results.crate_info.native_libraries[&cnum]
+                        .iter()
+                        .filter_map(|lib| lib.filename)
+                        .collect::<FxHashSet<_>>()
+                } else {
+                    Default::default()
+                };
+                add_static_crate(
+                    cmd,
+                    sess,
+                    archive_builder_builder,
+                    codegen_results,
+                    tmpdir,
+                    cnum,
+                    &bundled_libs,
+                );
 
                 // Link static native libs with "-bundle" modifier only if the crate they originate from
                 // is being linked statically to the current crate.  If it's linked dynamically
@@ -2419,6 +2409,14 @@ fn add_upstream_rust_crates<'a>(
                 // external build system already has the native dependencies defined, and it
                 // will provide them to the linker itself.
                 if sess.opts.unstable_opts.link_native_libraries {
+                    if sess.opts.unstable_opts.packed_bundled_libs {
+                        // If rlib contains native libs as archives, unpack them to tmpdir.
+                        let rlib = &src.rlib.as_ref().unwrap().0;
+                        archive_builder_builder
+                            .extract_bundled_libs(rlib, tmpdir, &bundled_libs)
+                            .unwrap_or_else(|e| sess.fatal(e));
+                    }
+
                     let mut last = (None, NativeLibKind::Unspecified, None);
                     for lib in &codegen_results.crate_info.native_libraries[&cnum] {
                         let Some(name) = lib.name else {
@@ -2451,6 +2449,14 @@ fn add_upstream_rust_crates<'a>(
                                 bundle: Some(false),
                                 whole_archive: Some(false) | None,
                             } => {
+                                // HACK/FIXME: Fixup a circular dependency between libgcc and libc
+                                // with glibc. This logic should be moved to the libc crate.
+                                if sess.target.os == "linux"
+                                    && sess.target.env == "gnu"
+                                    && name == "c"
+                                {
+                                    cmd.link_staticlib("gcc", false);
+                                }
                                 cmd.link_staticlib(name, lib.verbatim.unwrap_or(false));
                             }
                             NativeLibKind::LinkArg => {
@@ -2460,20 +2466,23 @@ fn add_upstream_rust_crates<'a>(
                             | NativeLibKind::Framework { .. }
                             | NativeLibKind::Unspecified
                             | NativeLibKind::RawDylib => {}
-                            NativeLibKind::Static {
-                                bundle: Some(true) | None,
-                                whole_archive: _,
-                            } => {}
+                            NativeLibKind::Static { bundle: Some(true) | None, whole_archive } => {
+                                if sess.opts.unstable_opts.packed_bundled_libs {
+                                    // If rlib contains native libs as archives, they are unpacked to tmpdir.
+                                    let path = tmpdir.join(lib.filename.unwrap().as_str());
+                                    if whole_archive == Some(true) {
+                                        cmd.link_whole_rlib(&path);
+                                    } else {
+                                        cmd.link_rlib(&path);
+                                    }
+                                }
+                            }
                         }
                     }
                 }
             }
             Linkage::Dynamic => add_dynamic_crate(cmd, sess, &src.dylib.as_ref().unwrap().0),
         }
-
-        if group_end == Some(cnum) {
-            cmd.group_end();
-        }
     }
 
     // compiler-builtins are always placed last to ensure that they're
@@ -2482,7 +2491,15 @@ fn add_upstream_rust_crates<'a>(
     // was already "included" in a dylib (e.g., `libstd` when `-C prefer-dynamic`
     // is used)
     if let Some(cnum) = compiler_builtins {
-        add_static_crate(cmd, sess, archive_builder_builder, codegen_results, tmpdir, cnum);
+        add_static_crate(
+            cmd,
+            sess,
+            archive_builder_builder,
+            codegen_results,
+            tmpdir,
+            cnum,
+            &Default::default(),
+        );
     }
 
     // Converts a library file-stem into a cc -l argument
@@ -2515,6 +2532,7 @@ fn add_upstream_rust_crates<'a>(
         codegen_results: &CodegenResults,
         tmpdir: &Path,
         cnum: CrateNum,
+        bundled_lib_file_names: &FxHashSet<Symbol>,
     ) {
         let src = &codegen_results.crate_info.used_crate_source[&cnum];
         let cratepath = &src.rlib.as_ref().unwrap().0;
@@ -2543,6 +2561,7 @@ fn add_upstream_rust_crates<'a>(
         let dst = tmpdir.join(cratepath.file_name().unwrap());
         let name = cratepath.file_name().unwrap().to_str().unwrap();
         let name = &name[3..name.len() - 5]; // chop off lib/.rlib
+        let bundled_lib_file_names = bundled_lib_file_names.clone();
 
         sess.prof.generic_activity_with_arg("link_altering_rlib", name).run(|| {
             let canonical_name = name.replace('-', "_");
@@ -2576,6 +2595,15 @@ fn add_upstream_rust_crates<'a>(
                     let skip_because_lto =
                         upstream_rust_objects_already_included && is_rust_object && is_builtins;
 
+                    // We skip native libraries because:
+                    // 1. This native libraries won't be used from the generated rlib,
+                    //    so we can throw them away to avoid the copying work.
+                    // 2. We can't allow it to be a single remaining entry in archive
+                    //    as some linkers may complain on that.
+                    if bundled_lib_file_names.contains(&Symbol::intern(f)) {
+                        return true;
+                    }
+
                     if skip_because_cfg_say_so || skip_because_lto {
                         return true;
                     }
@@ -2797,20 +2825,24 @@ fn add_gcc_ld_path(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         if let LinkerFlavor::Gcc = flavor {
             match ld_impl {
                 LdImpl::Lld => {
-                    let tools_path = sess.get_tools_search_paths(false);
-                    let gcc_ld_dir = tools_path
-                        .into_iter()
-                        .map(|p| p.join("gcc-ld"))
-                        .find(|p| {
-                            p.join(if sess.host.is_like_windows { "ld.exe" } else { "ld" }).exists()
-                        })
-                        .unwrap_or_else(|| sess.fatal("rust-lld (as ld) not found"));
-                    cmd.arg({
-                        let mut arg = OsString::from("-B");
-                        arg.push(gcc_ld_dir);
-                        arg
-                    });
-                    cmd.arg(format!("-Wl,-rustc-lld-flavor={}", sess.target.lld_flavor.as_str()));
+                    // Implement the "self-contained" part of -Zgcc-ld
+                    // by adding rustc distribution directories to the tool search path.
+                    for path in sess.get_tools_search_paths(false) {
+                        cmd.arg({
+                            let mut arg = OsString::from("-B");
+                            arg.push(path.join("gcc-ld"));
+                            arg
+                        });
+                    }
+                    // Implement the "linker flavor" part of -Zgcc-ld
+                    // by asking cc to use some kind of lld.
+                    cmd.arg("-fuse-ld=lld");
+                    if sess.target.lld_flavor != LldFlavor::Ld {
+                        // Tell clang to use a non-default LLD flavor.
+                        // Gcc doesn't understand the target option, but we currently assume
+                        // that gcc is not used for Apple and Wasm targets (#97402).
+                        cmd.arg(format!("--target={}", sess.target.llvm_target));
+                    }
                 }
             }
         } else {
diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index ce51b2e9531f..e0bd7a33f737 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -1,4 +1,3 @@
-use super::archive;
 use super::command::Command;
 use super::symbol_export;
 use rustc_span::symbol::sym;
@@ -11,6 +10,7 @@ use std::path::{Path, PathBuf};
 use std::{env, mem, str};
 
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
+use rustc_metadata::find_native_static_library;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo, SymbolExportKind};
 use rustc_middle::ty::TyCtxt;
@@ -126,29 +126,26 @@ pub fn get_linker<'a>(
     // to the linker args construction.
     assert!(cmd.get_args().is_empty() || sess.target.vendor == "uwp");
     match flavor {
-        LinkerFlavor::Lld(LldFlavor::Link) | LinkerFlavor::Msvc => {
-            Box::new(MsvcLinker { cmd, sess }) as Box<dyn Linker>
-        }
-        LinkerFlavor::Em => Box::new(EmLinker { cmd, sess }) as Box<dyn Linker>,
         LinkerFlavor::Gcc => {
             Box::new(GccLinker { cmd, sess, target_cpu, hinted_static: false, is_ld: false })
                 as Box<dyn Linker>
         }
-
+        LinkerFlavor::Ld if sess.target.os == "l4re" => {
+            Box::new(L4Bender::new(cmd, sess)) as Box<dyn Linker>
+        }
         LinkerFlavor::Lld(LldFlavor::Ld)
         | LinkerFlavor::Lld(LldFlavor::Ld64)
         | LinkerFlavor::Ld => {
             Box::new(GccLinker { cmd, sess, target_cpu, hinted_static: false, is_ld: true })
                 as Box<dyn Linker>
         }
-
+        LinkerFlavor::Lld(LldFlavor::Link) | LinkerFlavor::Msvc => {
+            Box::new(MsvcLinker { cmd, sess }) as Box<dyn Linker>
+        }
         LinkerFlavor::Lld(LldFlavor::Wasm) => Box::new(WasmLd::new(cmd, sess)) as Box<dyn Linker>,
-
-        LinkerFlavor::PtxLinker => Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>,
-
-        LinkerFlavor::BpfLinker => Box::new(BpfLinker { cmd, sess }) as Box<dyn Linker>,
-
-        LinkerFlavor::L4Bender => Box::new(L4Bender::new(cmd, sess)) as Box<dyn Linker>,
+        LinkerFlavor::EmCc => Box::new(EmLinker { cmd, sess }) as Box<dyn Linker>,
+        LinkerFlavor::Bpf => Box::new(BpfLinker { cmd, sess }) as Box<dyn Linker>,
+        LinkerFlavor::Ptx => Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>,
     }
 }
 
@@ -186,8 +183,6 @@ pub trait Linker {
     fn no_default_libraries(&mut self);
     fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]);
     fn subsystem(&mut self, subsystem: &str);
-    fn group_start(&mut self);
-    fn group_end(&mut self);
     fn linker_plugin_lto(&mut self);
     fn add_eh_frame_header(&mut self) {}
     fn add_no_exec(&mut self) {}
@@ -444,7 +439,10 @@ impl<'a> Linker for GccLinker<'a> {
             }
         }
         self.hint_dynamic();
-        self.cmd.arg(format!("-l{}{}", if verbatim { ":" } else { "" }, lib));
+        self.cmd.arg(format!(
+            "-l{}{lib}",
+            if verbatim && self.sess.target.linker_is_gnu { ":" } else { "" },
+        ));
         if !as_needed {
             if self.sess.target.is_like_osx {
                 // See above FIXME comment
@@ -455,7 +453,10 @@ impl<'a> Linker for GccLinker<'a> {
     }
     fn link_staticlib(&mut self, lib: &str, verbatim: bool) {
         self.hint_static();
-        self.cmd.arg(format!("-l{}{}", if verbatim { ":" } else { "" }, lib));
+        self.cmd.arg(format!(
+            "-l{}{lib}",
+            if verbatim && self.sess.target.linker_is_gnu { ":" } else { "" },
+        ));
     }
     fn link_rlib(&mut self, lib: &Path) {
         self.hint_static();
@@ -509,17 +510,17 @@ impl<'a> Linker for GccLinker<'a> {
         self.hint_static();
         let target = &self.sess.target;
         if !target.is_like_osx {
-            self.linker_arg("--whole-archive").cmd.arg(format!(
-                "-l{}{}",
-                if verbatim { ":" } else { "" },
-                lib
+            self.linker_arg("--whole-archive");
+            self.cmd.arg(format!(
+                "-l{}{lib}",
+                if verbatim && self.sess.target.linker_is_gnu { ":" } else { "" },
             ));
             self.linker_arg("--no-whole-archive");
         } else {
             // -force_load is the macOS equivalent of --whole-archive, but it
             // involves passing the full path to the library to link.
             self.linker_arg("-force_load");
-            let lib = archive::find_library(lib, verbatim, search_path, &self.sess);
+            let lib = find_native_static_library(lib, Some(verbatim), search_path, &self.sess);
             self.linker_arg(&lib);
         }
     }
@@ -733,18 +734,6 @@ impl<'a> Linker for GccLinker<'a> {
         self.hint_dynamic(); // Reset to default before returning the composed command line.
     }
 
-    fn group_start(&mut self) {
-        if self.takes_hints() {
-            self.linker_arg("--start-group");
-        }
-    }
-
-    fn group_end(&mut self) {
-        if self.takes_hints() {
-            self.linker_arg("--end-group");
-        }
-    }
-
     fn linker_plugin_lto(&mut self) {
         match self.sess.opts.cg.linker_plugin_lto {
             LinkerPluginLto::Disabled => {
@@ -1022,10 +1011,6 @@ impl<'a> Linker for MsvcLinker<'a> {
         }
     }
 
-    // MSVC doesn't need group indicators
-    fn group_start(&mut self) {}
-    fn group_end(&mut self) {}
-
     fn linker_plugin_lto(&mut self) {
         // Do nothing
     }
@@ -1168,10 +1153,6 @@ impl<'a> Linker for EmLinker<'a> {
         // noop
     }
 
-    // Appears not necessary on Emscripten
-    fn group_start(&mut self) {}
-    fn group_end(&mut self) {}
-
     fn linker_plugin_lto(&mut self) {
         // Do nothing
     }
@@ -1347,10 +1328,6 @@ impl<'a> Linker for WasmLd<'a> {
 
     fn subsystem(&mut self, _subsystem: &str) {}
 
-    // Not needed for now with LLD
-    fn group_start(&mut self) {}
-    fn group_end(&mut self) {}
-
     fn linker_plugin_lto(&mut self) {
         // Do nothing for now
     }
@@ -1479,14 +1456,6 @@ impl<'a> Linker for L4Bender<'a> {
         self.hint_static(); // Reset to default before returning the composed command line.
     }
 
-    fn group_start(&mut self) {
-        self.cmd.arg("--start-group");
-    }
-
-    fn group_end(&mut self) {
-        self.cmd.arg("--end-group");
-    }
-
     fn linker_plugin_lto(&mut self) {}
 
     fn control_flow_guard(&mut self) {}
@@ -1667,10 +1636,6 @@ impl<'a> Linker for PtxLinker<'a> {
 
     fn subsystem(&mut self, _subsystem: &str) {}
 
-    fn group_start(&mut self) {}
-
-    fn group_end(&mut self) {}
-
     fn linker_plugin_lto(&mut self) {}
 }
 
@@ -1780,9 +1745,5 @@ impl<'a> Linker for BpfLinker<'a> {
 
     fn subsystem(&mut self, _subsystem: &str) {}
 
-    fn group_start(&mut self) {}
-
-    fn group_end(&mut self) {}
-
     fn linker_plugin_lto(&mut self) {}
 }
diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index 32b340832ce2..8d7e2c5cf393 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -540,7 +540,7 @@ pub fn linking_symbol_name_for_instance_in_crate<'tcx>(
         .map(|fnabi| (fnabi.conv, &fnabi.args[..]))
         .unwrap_or((Conv::Rust, &[]));
 
-    // Decorate symbols with prefices, suffices and total number of bytes of arguments.
+    // Decorate symbols with prefixes, suffixes and total number of bytes of arguments.
     // Reference: https://docs.microsoft.com/en-us/cpp/build/reference/decorated-names?view=msvc-170
     let (prefix, suffix) = match conv {
         Conv::X86Fastcall => ("@", "@"),
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index 68f3b19b715a..680b9b642d9b 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -113,7 +113,6 @@ pub struct ModuleConfig {
     pub vectorize_slp: bool,
     pub merge_functions: bool,
     pub inline_threshold: Option<u32>,
-    pub new_llvm_pass_manager: Option<bool>,
     pub emit_lifetime_markers: bool,
     pub llvm_plugins: Vec<String>,
 }
@@ -265,7 +264,6 @@ impl ModuleConfig {
             },
 
             inline_threshold: sess.opts.cg.inline_threshold,
-            new_llvm_pass_manager: sess.opts.unstable_opts.new_llvm_pass_manager,
             emit_lifetime_markers: sess.emit_lifetime_markers(),
             llvm_plugins: if_regular!(sess.opts.unstable_opts.llvm_plugins.clone(), vec![]),
         }
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 4c6be3f91082..35fd86c17357 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -12,7 +12,7 @@ use crate::traits::*;
 use crate::{CachedModuleCodegen, CompiledModule, CrateInfo, MemFlags, ModuleCodegen, ModuleKind};
 
 use rustc_attr as attr;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
 
 use rustc_data_structures::sync::par_iter;
@@ -21,10 +21,12 @@ use rustc_data_structures::sync::ParallelIterator;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
+use rustc_hir::weak_lang_items::WEAK_ITEMS_SYMBOLS;
 use rustc_index::vec::Idx;
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::middle::exported_symbols;
+use rustc_middle::middle::exported_symbols::SymbolExportKind;
 use rustc_middle::middle::lang_items;
 use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
@@ -34,6 +36,7 @@ use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{self, CrateType, EntryFnType, OutputType};
 use rustc_session::Session;
 use rustc_span::symbol::sym;
+use rustc_span::Symbol;
 use rustc_span::{DebuggerVisualizerFile, DebuggerVisualizerType};
 use rustc_target::abi::{Align, VariantIdx};
 
@@ -163,6 +166,11 @@ pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             if let Some(entry_idx) = vptr_entry_idx {
                 let ptr_ty = cx.type_i8p();
                 let ptr_align = cx.tcx().data_layout.pointer_align.abi;
+                let vtable_ptr_ty = cx.scalar_pair_element_backend_type(
+                    cx.layout_of(cx.tcx().mk_mut_ptr(target)),
+                    1,
+                    true,
+                );
                 let llvtable = bx.pointercast(old_info, bx.type_ptr_to(ptr_ty));
                 let gep = bx.inbounds_gep(
                     ptr_ty,
@@ -173,7 +181,7 @@ pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 bx.nonnull_metadata(new_vptr);
                 // VTable loads are invariant.
                 bx.set_invariant_load(new_vptr);
-                new_vptr
+                bx.pointercast(new_vptr, vtable_ptr_ty)
             } else {
                 old_info
             }
@@ -389,15 +397,14 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     let main_llfn = cx.get_fn_addr(instance);
 
-    let use_start_lang_item = EntryFnType::Start != entry_type;
-    let entry_fn = create_entry_fn::<Bx>(cx, main_llfn, main_def_id, use_start_lang_item);
+    let entry_fn = create_entry_fn::<Bx>(cx, main_llfn, main_def_id, entry_type);
     return Some(entry_fn);
 
     fn create_entry_fn<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         cx: &'a Bx::CodegenCx,
         rust_main: Bx::Value,
         rust_main_def_id: DefId,
-        use_start_lang_item: bool,
+        entry_type: EntryFnType,
     ) -> Bx::Function {
         // The entry function is either `int main(void)` or `int main(int argc, char **argv)`,
         // depending on whether the target needs `argc` and `argv` to be passed in.
@@ -442,7 +449,7 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         let i8pp_ty = cx.type_ptr_to(cx.type_i8p());
         let (arg_argc, arg_argv) = get_argc_argv(cx, &mut bx);
 
-        let (start_fn, start_ty, args) = if use_start_lang_item {
+        let (start_fn, start_ty, args) = if let EntryFnType::Main { sigpipe } = entry_type {
             let start_def_id = cx.tcx().require_lang_item(LangItem::Start, None);
             let start_fn = cx.get_fn_addr(
                 ty::Instance::resolve(
@@ -454,8 +461,13 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 .unwrap()
                 .unwrap(),
             );
-            let start_ty = cx.type_func(&[cx.val_ty(rust_main), isize_ty, i8pp_ty], isize_ty);
-            (start_fn, start_ty, vec![rust_main, arg_argc, arg_argv])
+
+            let i8_ty = cx.type_i8();
+            let arg_sigpipe = bx.const_u8(sigpipe);
+
+            let start_ty =
+                cx.type_func(&[cx.val_ty(rust_main), isize_ty, i8pp_ty, i8_ty], isize_ty);
+            (start_fn, start_ty, vec![rust_main, arg_argc, arg_argv, arg_sigpipe])
         } else {
             debug!("using user-defined start fn");
             let start_ty = cx.type_func(&[isize_ty, i8pp_ty], isize_ty);
@@ -811,21 +823,16 @@ impl CrateInfo {
             crate_name: Default::default(),
             used_crates,
             used_crate_source: Default::default(),
-            lang_item_to_crate: Default::default(),
-            missing_lang_items: Default::default(),
             dependency_formats: tcx.dependency_formats(()).clone(),
             windows_subsystem,
             natvis_debugger_visualizers: Default::default(),
         };
-        let lang_items = tcx.lang_items();
-
         let crates = tcx.crates(());
 
         let n_crates = crates.len();
         info.native_libraries.reserve(n_crates);
         info.crate_name.reserve(n_crates);
         info.used_crate_source.reserve(n_crates);
-        info.missing_lang_items.reserve(n_crates);
 
         for &cnum in crates.iter() {
             info.native_libraries
@@ -843,17 +850,37 @@ impl CrateInfo {
             if tcx.is_no_builtins(cnum) {
                 info.is_no_builtins.insert(cnum);
             }
-            let missing = tcx.missing_lang_items(cnum);
-            for &item in missing.iter() {
-                if let Ok(id) = lang_items.require(item) {
-                    info.lang_item_to_crate.insert(item, id.krate);
-                }
-            }
+        }
 
-            // No need to look for lang items that don't actually need to exist.
-            let missing =
-                missing.iter().cloned().filter(|&l| lang_items::required(tcx, l)).collect();
-            info.missing_lang_items.insert(cnum, missing);
+        // Handle circular dependencies in the standard library.
+        // See comment before `add_linked_symbol_object` function for the details.
+        // With msvc-like linkers it's both unnecessary (they support circular dependencies),
+        // and causes linking issues (when weak lang item symbols are "privatized" by LTO).
+        let target = &tcx.sess.target;
+        if !target.is_like_msvc {
+            let missing_weak_lang_items: FxHashSet<&Symbol> = info
+                .used_crates
+                .iter()
+                .flat_map(|cnum| {
+                    tcx.missing_lang_items(*cnum)
+                        .iter()
+                        .filter(|l| lang_items::required(tcx, **l))
+                        .filter_map(|item| WEAK_ITEMS_SYMBOLS.get(item))
+                })
+                .collect();
+            let prefix = if target.is_like_windows && target.arch == "x86" { "_" } else { "" };
+            info.linked_symbols
+                .iter_mut()
+                .filter(|(crate_type, _)| {
+                    !matches!(crate_type, CrateType::Rlib | CrateType::Staticlib)
+                })
+                .for_each(|(_, linked_symbols)| {
+                    linked_symbols.extend(
+                        missing_weak_lang_items
+                            .iter()
+                            .map(|item| (format!("{prefix}{item}"), SymbolExportKind::Text)),
+                    )
+                });
         }
 
         let embed_visualizers = tcx.sess.crate_types().iter().any(|&crate_type| match crate_type {
@@ -874,7 +901,7 @@ impl CrateInfo {
             }
         });
 
-        if tcx.sess.target.is_like_msvc && embed_visualizers {
+        if target.is_like_msvc && embed_visualizers {
             info.natvis_debugger_visualizers =
                 collect_debugger_visualizers_transitive(tcx, DebuggerVisualizerType::Natvis);
         }
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 0faf51b062b4..3ef9a634e185 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -1,7 +1,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(box_patterns)]
 #![feature(try_blocks)]
-#![feature(let_else)]
 #![feature(once_cell)]
 #![feature(associated_type_bounds)]
 #![feature(strict_provenance)]
@@ -25,7 +24,6 @@ use rustc_ast as ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::Lrc;
 use rustc_hir::def_id::CrateNum;
-use rustc_hir::LangItem;
 use rustc_middle::dep_graph::WorkProduct;
 use rustc_middle::middle::dependency_format::Dependencies;
 use rustc_middle::middle::exported_symbols::SymbolExportKind;
@@ -113,6 +111,7 @@ bitflags::bitflags! {
 pub struct NativeLib {
     pub kind: NativeLibKind,
     pub name: Option<Symbol>,
+    pub filename: Option<Symbol>,
     pub cfg: Option<ast::MetaItem>,
     pub verbatim: Option<bool>,
     pub dll_imports: Vec<cstore::DllImport>,
@@ -122,6 +121,7 @@ impl From<&cstore::NativeLib> for NativeLib {
     fn from(lib: &cstore::NativeLib) -> Self {
         NativeLib {
             kind: lib.kind,
+            filename: lib.filename,
             name: lib.name,
             cfg: lib.cfg.clone(),
             verbatim: lib.verbatim,
@@ -152,8 +152,6 @@ pub struct CrateInfo {
     pub used_libraries: Vec<NativeLib>,
     pub used_crate_source: FxHashMap<CrateNum, Lrc<CrateSource>>,
     pub used_crates: Vec<CrateNum>,
-    pub lang_item_to_crate: FxHashMap<LangItem, CrateNum>,
-    pub missing_lang_items: FxHashMap<CrateNum, Vec<LangItem>>,
     pub dependency_formats: Lrc<Dependencies>,
     pub windows_subsystem: Option<String>,
     pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs
index f8e982b77518..cae46ebd2e9a 100644
--- a/compiler/rustc_codegen_ssa/src/meth.rs
+++ b/compiler/rustc_codegen_ssa/src/meth.rs
@@ -69,7 +69,7 @@ impl<'a, 'tcx> VirtualIndex {
 fn expect_dyn_trait_in_self<'tcx>(ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'tcx> {
     for arg in ty.peel_refs().walk() {
         if let GenericArgKind::Type(ty) = arg.unpack() {
-            if let ty::Dynamic(data, _) = ty.kind() {
+            if let ty::Dynamic(data, _, _) = ty.kind() {
                 return data.principal().expect("expected principal trait object");
             }
         }
@@ -86,6 +86,7 @@ fn expect_dyn_trait_in_self<'tcx>(ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'
 /// The `trait_ref` encodes the erased self type. Hence if we are
 /// making an object `Foo<dyn Trait>` from a value of type `Foo<T>`, then
 /// `trait_ref` would map `T: Trait`.
+#[instrument(level = "debug", skip(cx))]
 pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
     cx: &Cx,
     ty: Ty<'tcx>,
@@ -93,8 +94,6 @@ pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
 ) -> Cx::Value {
     let tcx = cx.tcx();
 
-    debug!("get_vtable(ty={:?}, trait_ref={:?})", ty, trait_ref);
-
     // Check the cache.
     if let Some(&val) = cx.vtables().borrow().get(&(ty, trait_ref)) {
         return val;
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 5c67d3b6431f..a6b226ef7209 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -13,8 +13,7 @@ use rustc_ast as ast;
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_hir::lang_items::LangItem;
 use rustc_index::vec::Idx;
-use rustc_middle::mir::AssertKind;
-use rustc_middle::mir::{self, SwitchTargets};
+use rustc_middle::mir::{self, AssertKind, SwitchTargets};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
 use rustc_middle::ty::{self, Instance, Ty, TypeVisitable};
@@ -368,6 +367,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         bx.ret(llval);
     }
 
+    #[tracing::instrument(level = "trace", skip(self, helper, bx))]
     fn codegen_drop_terminator(
         &mut self,
         helper: TerminatorCodegenHelper<'tcx>,
@@ -398,13 +398,29 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let (drop_fn, fn_abi) = match ty.kind() {
             // FIXME(eddyb) perhaps move some of this logic into
             // `Instance::resolve_drop_in_place`?
-            ty::Dynamic(..) => {
+            ty::Dynamic(_, _, ty::Dyn) => {
+                // IN THIS ARM, WE HAVE:
+                // ty = *mut (dyn Trait)
+                // which is: exists<T> ( *mut T,    Vtable<T: Trait> )
+                //                       args[0]    args[1]
+                //
+                // args = ( Data, Vtable )
+                //                  |
+                //                  v
+                //                /-------\
+                //                | ...   |
+                //                \-------/
+                //
                 let virtual_drop = Instance {
                     def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
                     substs: drop_fn.substs,
                 };
+                debug!("ty = {:?}", ty);
+                debug!("drop_fn = {:?}", drop_fn);
+                debug!("args = {:?}", args);
                 let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty());
                 let vtable = args[1];
+                // Truncate vtable off of args list
                 args = &args[..1];
                 (
                     meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE)
@@ -412,6 +428,51 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     fn_abi,
                 )
             }
+            ty::Dynamic(_, _, ty::DynStar) => {
+                // IN THIS ARM, WE HAVE:
+                // ty = *mut (dyn* Trait)
+                // which is: *mut exists<T: sizeof(T) == sizeof(usize)> (T, Vtable<T: Trait>)
+                //
+                // args = [ * ]
+                //          |
+                //          v
+                //      ( Data, Vtable )
+                //                |
+                //                v
+                //              /-------\
+                //              | ...   |
+                //              \-------/
+                //
+                //
+                // WE CAN CONVERT THIS INTO THE ABOVE LOGIC BY DOING
+                //
+                // data = &(*args[0]).0    // gives a pointer to Data above (really the same pointer)
+                // vtable = (*args[0]).1   // loads the vtable out
+                // (data, vtable)          // an equivalent Rust `*mut dyn Trait`
+                //
+                // SO THEN WE CAN USE THE ABOVE CODE.
+                let virtual_drop = Instance {
+                    def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
+                    substs: drop_fn.substs,
+                };
+                debug!("ty = {:?}", ty);
+                debug!("drop_fn = {:?}", drop_fn);
+                debug!("args = {:?}", args);
+                let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty());
+                let data = args[0];
+                let data_ty = bx.cx().backend_type(place.layout);
+                let vtable_ptr =
+                    bx.gep(data_ty, data, &[bx.cx().const_i32(0), bx.cx().const_i32(1)]);
+                let vtable = bx.load(bx.type_i8p(), vtable_ptr, abi::Align::ONE);
+                // Truncate vtable off of args list
+                args = &args[..1];
+                debug!("args' = {:?}", args);
+                (
+                    meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE)
+                        .get_fn(&mut bx, vtable, ty, &fn_abi),
+                    fn_abi,
+                )
+            }
             _ => (bx.get_fn_addr(drop_fn), bx.fn_abi_of_instance(drop_fn, ty::List::empty())),
         };
         helper.do_call(
@@ -846,7 +907,30 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         llargs.push(data_ptr);
                         continue;
                     }
-                    _ => span_bug!(span, "can't codegen a virtual call on {:?}", op),
+                    Immediate(_) => {
+                        let ty::Ref(_, ty, _) = op.layout.ty.kind() else {
+                            span_bug!(span, "can't codegen a virtual call on {:#?}", op);
+                        };
+                        if !ty.is_dyn_star() {
+                            span_bug!(span, "can't codegen a virtual call on {:#?}", op);
+                        }
+                        // FIXME(dyn-star): Make sure this is done on a &dyn* receiver
+                        let place = op.deref(bx.cx());
+                        let data_ptr = place.project_field(&mut bx, 0);
+                        let meta_ptr = place.project_field(&mut bx, 1);
+                        let meta = bx.load_operand(meta_ptr);
+                        llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(
+                            &mut bx,
+                            meta.immediate(),
+                            op.layout.ty,
+                            &fn_abi,
+                        ));
+                        llargs.push(data_ptr.llval);
+                        continue;
+                    }
+                    _ => {
+                        span_bug!(span, "can't codegen a virtual call on {:#?}", op);
+                    }
                 }
             }
 
diff --git a/compiler/rustc_codegen_ssa/src/mir/constant.rs b/compiler/rustc_codegen_ssa/src/mir/constant.rs
index 9a995fbf65ca..4c6ab457c494 100644
--- a/compiler/rustc_codegen_ssa/src/mir/constant.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/constant.rs
@@ -25,26 +25,26 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         constant: &mir::Constant<'tcx>,
     ) -> Result<ConstValue<'tcx>, ErrorHandled> {
         let ct = self.monomorphize(constant.literal);
-        let ct = match ct {
-            mir::ConstantKind::Ty(ct) => ct,
+        let uv = match ct {
+            mir::ConstantKind::Ty(ct) => match ct.kind() {
+                ty::ConstKind::Unevaluated(uv) => uv.expand(),
+                ty::ConstKind::Value(val) => {
+                    return Ok(self.cx.tcx().valtree_to_const_val((ct.ty(), val)));
+                }
+                err => span_bug!(
+                    constant.span,
+                    "encountered bad ConstKind after monomorphizing: {:?}",
+                    err
+                ),
+            },
+            mir::ConstantKind::Unevaluated(uv, _) => uv,
             mir::ConstantKind::Val(val, _) => return Ok(val),
         };
-        match ct.kind() {
-            ty::ConstKind::Unevaluated(ct) => self
-                .cx
-                .tcx()
-                .const_eval_resolve(ty::ParamEnv::reveal_all(), ct, None)
-                .map_err(|err| {
-                    self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
-                    err
-                }),
-            ty::ConstKind::Value(val) => Ok(self.cx.tcx().valtree_to_const_val((ct.ty(), val))),
-            err => span_bug!(
-                constant.span,
-                "encountered bad ConstKind after monomorphizing: {:?}",
-                err
-            ),
-        }
+
+        self.cx.tcx().const_eval_resolve(ty::ParamEnv::reveal_all(), uv, None).map_err(|err| {
+            self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
+            err
+        })
     }
 
     /// process constant containing SIMD shuffle indices
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index 8c3186efc630..157c1c82311d 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -3,7 +3,7 @@ use rustc_index::vec::IndexVec;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir;
 use rustc_middle::ty;
-use rustc_middle::ty::layout::LayoutOf;
+use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
 use rustc_session::config::DebugInfo;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{BytePos, Span};
@@ -93,15 +93,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     }
 
     /// In order to have a good line stepping behavior in debugger, we overwrite debug
-    /// locations of macro expansions with that of the outermost expansion site
-    /// (unless the crate is being compiled with `-Z debug-macros`).
+    /// locations of macro expansions with that of the outermost expansion site (when the macro is
+    /// annotated with `#[collapse_debuginfo]` or when `-Zdebug-macros` is provided).
     fn adjust_span_for_debugging(&self, mut span: Span) -> Span {
         // Bail out if debug info emission is not enabled.
         if self.debug_context.is_none() {
             return span;
         }
 
-        if span.from_expansion() && !self.cx.sess().opts.unstable_opts.debug_macros {
+        if self.cx.tcx().should_collapse_debuginfo(span) {
             // Walk up the macro expansion chain until we reach a non-expanded span.
             // We also stop at the function body level because no line stepping can occur
             // at the level above that.
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index 16aad07194da..215edbe02c08 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -77,10 +77,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 
         let llval = match name {
-            sym::assume => {
-                bx.assume(args[0].immediate());
-                return;
-            }
             sym::abort => {
                 bx.abort();
                 return;
@@ -555,14 +551,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 return;
             }
 
-            sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {
+            sym::ptr_guaranteed_cmp => {
                 let a = args[0].immediate();
                 let b = args[1].immediate();
-                if name == sym::ptr_guaranteed_eq {
-                    bx.icmp(IntPredicate::IntEQ, a, b)
-                } else {
-                    bx.icmp(IntPredicate::IntNE, a, b)
-                }
+                bx.icmp(IntPredicate::IntEQ, a, b)
             }
 
             sym::ptr_offset_from | sym::ptr_offset_from_unsigned => {
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index d6bbcd992345..2b931bfc91d6 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -191,7 +191,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 // errored or at least linted
                 ErrorHandled::Reported(_) | ErrorHandled::Linted => {}
                 ErrorHandled::TooGeneric => {
-                    span_bug!(const_.span, "codgen encountered polymorphic constant: {:?}", err)
+                    span_bug!(const_.span, "codegen encountered polymorphic constant: {:?}", err)
                 }
             }
         }
diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs
index c612634fce2a..37b1e036247b 100644
--- a/compiler/rustc_codegen_ssa/src/mir/operand.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs
@@ -72,10 +72,6 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
     ) -> Self {
         let layout = bx.layout_of(ty);
 
-        if layout.is_zst() {
-            return OperandRef::new_zst(bx, layout);
-        }
-
         let val = match val {
             ConstValue::Scalar(x) => {
                 let Abi::Scalar(scalar) = layout.abi else {
@@ -84,10 +80,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
                 let llval = bx.scalar_to_backend(x, scalar, bx.immediate_backend_type(layout));
                 OperandValue::Immediate(llval)
             }
-            ConstValue::ZeroSized => {
-                let llval = bx.zst_to_backend(bx.immediate_backend_type(layout));
-                OperandValue::Immediate(llval)
-            }
+            ConstValue::ZeroSized => return OperandRef::new_zst(bx, layout),
             ConstValue::Slice { data, start, end } => {
                 let Abi::ScalarPair(a_scalar, _) = layout.abi else {
                     bug!("from_const: invalid ScalarPair layout: {:#?}", layout);
diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs
index 268c4d765030..9c18df5643f1 100644
--- a/compiler/rustc_codegen_ssa/src/mir/place.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/place.rs
@@ -4,7 +4,6 @@ use super::{FunctionCx, LocalRef};
 use crate::common::IntPredicate;
 use crate::glue;
 use crate::traits::*;
-use crate::MemFlags;
 
 use rustc_middle::mir;
 use rustc_middle::mir::tcx::PlaceTy;
@@ -245,7 +244,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
                 };
                 bx.intcast(tag.immediate(), cast_to, signed)
             }
-            TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
+            TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start } => {
                 // Rebase from niche values to discriminants, and check
                 // whether the result is in range for the niche variants.
                 let niche_llty = bx.cx().immediate_backend_type(tag.layout);
@@ -303,7 +302,7 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
                 bx.select(
                     is_niche,
                     niche_discr,
-                    bx.cx().const_uint(cast_to, dataful_variant.as_u32() as u64),
+                    bx.cx().const_uint(cast_to, untagged_variant.as_u32() as u64),
                 )
             }
         }
@@ -338,21 +337,11 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
             }
             Variants::Multiple {
                 tag_encoding:
-                    TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start },
+                    TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start },
                 tag_field,
                 ..
             } => {
-                if variant_index != dataful_variant {
-                    if bx.cx().sess().target.arch == "arm"
-                        || bx.cx().sess().target.arch == "aarch64"
-                    {
-                        // FIXME(#34427): as workaround for LLVM bug on ARM,
-                        // use memset of 0 before assigning niche value.
-                        let fill_byte = bx.cx().const_u8(0);
-                        let size = bx.cx().const_usize(self.layout.size.bytes());
-                        bx.memset(self.llval, fill_byte, size, self.align, MemFlags::empty());
-                    }
-
+                if variant_index != untagged_variant {
                     let niche = self.project_field(bx, tag_field);
                     let niche_llty = bx.cx().immediate_backend_type(niche.layout);
                     let niche_value = variant_index.as_u32() - niche_variants.start().as_u32();
@@ -411,6 +400,21 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> {
         downcast
     }
 
+    pub fn project_type<Bx: BuilderMethods<'a, 'tcx, Value = V>>(
+        &self,
+        bx: &mut Bx,
+        ty: Ty<'tcx>,
+    ) -> Self {
+        let mut downcast = *self;
+        downcast.layout = bx.cx().layout_of(ty);
+
+        // Cast to the appropriate type.
+        let variant_ty = bx.cx().backend_type(downcast.layout);
+        downcast.llval = bx.pointercast(downcast.llval, bx.cx().type_ptr_to(variant_ty));
+
+        downcast
+    }
+
     pub fn storage_live<Bx: BuilderMethods<'a, 'tcx, Value = V>>(&self, bx: &mut Bx) {
         bx.lifetime_start(self.llval, self.layout.size);
     }
@@ -453,6 +457,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 mir::ProjectionElem::Field(ref field, _) => {
                     cg_base.project_field(bx, field.index())
                 }
+                mir::ProjectionElem::OpaqueCast(ty) => cg_base.project_type(bx, ty),
                 mir::ProjectionElem::Index(index) => {
                     let index = &mir::Operand::Copy(mir::Place::from(index));
                     let index = self.codegen_operand(bx, index);
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index 26b9fbf44284..56852b0fcc82 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -4,6 +4,7 @@ use super::{FunctionCx, LocalRef};
 
 use crate::base;
 use crate::common::{self, IntPredicate};
+use crate::meth::get_vtable;
 use crate::traits::*;
 use crate::MemFlags;
 
@@ -87,7 +88,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     let size = bx.const_usize(dest.layout.size.bytes());
 
                     // Use llvm.memset.p0i8.* to initialize all zero arrays
-                    if bx.cx().const_to_opt_uint(v) == Some(0) {
+                    if bx.cx().const_to_opt_u128(v, false) == Some(0) {
                         let fill = bx.cx().const_u8(0);
                         bx.memset(start, fill, size, dest.align, MemFlags::empty());
                         return bx;
@@ -271,6 +272,21 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             bug!("unexpected non-pair operand");
                         }
                     }
+                    mir::CastKind::DynStar => {
+                        let data = match operand.val {
+                            OperandValue::Ref(_, _, _) => todo!(),
+                            OperandValue::Immediate(v) => v,
+                            OperandValue::Pair(_, _) => todo!(),
+                        };
+                        let trait_ref =
+                            if let ty::Dynamic(data, _, ty::DynStar) = cast.ty.kind() {
+                                data.principal()
+                            } else {
+                                bug!("Only valid to do a DynStar cast into a DynStar type")
+                            };
+                        let vtable = get_vtable(bx.cx(), source.ty(self.mir, bx.tcx()), trait_ref);
+                        OperandValue::Pair(data, vtable)
+                    }
                     mir::CastKind::Pointer(
                         PointerCast::MutToConstPointer | PointerCast::ArrayToPointer,
                     )
diff --git a/compiler/rustc_codegen_ssa/src/mir/statement.rs b/compiler/rustc_codegen_ssa/src/mir/statement.rs
index f452f29883f9..1db0fb3a6f1b 100644
--- a/compiler/rustc_codegen_ssa/src/mir/statement.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/statement.rs
@@ -1,4 +1,5 @@
 use rustc_middle::mir;
+use rustc_middle::mir::NonDivergingIntrinsic;
 
 use super::FunctionCx;
 use super::LocalRef;
@@ -73,11 +74,14 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 self.codegen_coverage(&mut bx, coverage.clone(), statement.source_info.scope);
                 bx
             }
-            mir::StatementKind::CopyNonOverlapping(box mir::CopyNonOverlapping {
-                ref src,
-                ref dst,
-                ref count,
-            }) => {
+            mir::StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(ref op)) => {
+                let op_val = self.codegen_operand(&mut bx, op);
+                bx.assume(op_val.immediate());
+                bx
+            }
+            mir::StatementKind::Intrinsic(box NonDivergingIntrinsic::CopyNonOverlapping(
+                mir::CopyNonOverlapping { ref count, ref src, ref dst },
+            )) => {
                 let dst_val = self.codegen_operand(&mut bx, dst);
                 let src_val = self.codegen_operand(&mut bx, src);
                 let count = self.codegen_operand(&mut bx, count).immediate();
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index 9062a83b8be4..0e259bcd1a48 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -210,8 +210,11 @@ const POWERPC_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("vsx", Some(sym::powerpc_target_feature)),
 ];
 
-const MIPS_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] =
-    &[("fp64", Some(sym::mips_target_feature)), ("msa", Some(sym::mips_target_feature))];
+const MIPS_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
+    ("fp64", Some(sym::mips_target_feature)),
+    ("msa", Some(sym::mips_target_feature)),
+    ("virt", Some(sym::mips_target_feature)),
+];
 
 const RISCV_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("m", Some(sym::riscv_target_feature)),
diff --git a/compiler/rustc_codegen_ssa/src/traits/consts.rs b/compiler/rustc_codegen_ssa/src/traits/consts.rs
index 8a91d4735ba0..fdc7a30e841e 100644
--- a/compiler/rustc_codegen_ssa/src/traits/consts.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/consts.rs
@@ -29,7 +29,6 @@ pub trait ConstMethods<'tcx>: BackendTypes {
     fn const_data_from_alloc(&self, alloc: ConstAllocation<'tcx>) -> Self::Value;
 
     fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, llty: Self::Type) -> Self::Value;
-    fn zst_to_backend(&self, llty: Self::Type) -> Self::Value;
     fn from_const_alloc(
         &self,
         layout: TyAndLayout<'tcx>,
diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index b46f71fc78a3..b52cc873f2e6 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -13,7 +13,7 @@ use rustc_middle::mir::pretty::display_allocation;
 use rustc_middle::traits::Reveal;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, subst::Subst, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::source_map::Span;
 use rustc_target::abi::{self, Abi};
 use std::borrow::Cow;
@@ -197,7 +197,7 @@ pub(super) fn op_to_const<'tcx>(
     }
 }
 
-#[instrument(skip(tcx), level = "debug")]
+#[instrument(skip(tcx), level = "debug", ret)]
 pub(crate) fn turn_into_const_value<'tcx>(
     tcx: TyCtxt<'tcx>,
     constant: ConstAlloc<'tcx>,
@@ -224,10 +224,7 @@ pub(crate) fn turn_into_const_value<'tcx>(
     );
 
     // Turn this into a proper constant.
-    let const_val = op_to_const(&ecx, &mplace.into());
-    debug!(?const_val);
-
-    const_val
+    op_to_const(&ecx, &mplace.into())
 }
 
 #[instrument(skip(tcx), level = "debug")]
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index 9ea9fbe0e0e5..e5acacd91888 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -35,21 +35,7 @@ impl<'mir, 'tcx> InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>> {
         // All `#[rustc_do_not_const_check]` functions should be hooked here.
         let def_id = instance.def_id();
 
-        if Some(def_id) == self.tcx.lang_items().const_eval_select() {
-            // redirect to const_eval_select_ct
-            if let Some(const_eval_select) = self.tcx.lang_items().const_eval_select_ct() {
-                return Ok(Some(
-                    ty::Instance::resolve(
-                        *self.tcx,
-                        ty::ParamEnv::reveal_all(),
-                        const_eval_select,
-                        instance.substs,
-                    )
-                    .unwrap()
-                    .unwrap(),
-                ));
-            }
-        } else if Some(def_id) == self.tcx.lang_items().panic_display()
+        if Some(def_id) == self.tcx.lang_items().panic_display()
             || Some(def_id) == self.tcx.lang_items().begin_panic_fn()
         {
             // &str or &&str
@@ -205,34 +191,35 @@ impl interpret::MayLeak for ! {
 }
 
 impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
-    fn guaranteed_eq(&mut self, a: Scalar, b: Scalar) -> InterpResult<'tcx, bool> {
+    /// See documentation on the `ptr_guaranteed_cmp` intrinsic.
+    fn guaranteed_cmp(&mut self, a: Scalar, b: Scalar) -> InterpResult<'tcx, u8> {
         Ok(match (a, b) {
             // Comparisons between integers are always known.
-            (Scalar::Int { .. }, Scalar::Int { .. }) => a == b,
-            // Equality with integers can never be known for sure.
-            (Scalar::Int { .. }, Scalar::Ptr(..)) | (Scalar::Ptr(..), Scalar::Int { .. }) => false,
-            // FIXME: return `true` for when both sides are the same pointer, *except* that
-            // some things (like functions and vtables) do not have stable addresses
-            // so we need to be careful around them (see e.g. #73722).
-            (Scalar::Ptr(..), Scalar::Ptr(..)) => false,
-        })
-    }
-
-    fn guaranteed_ne(&mut self, a: Scalar, b: Scalar) -> InterpResult<'tcx, bool> {
-        Ok(match (a, b) {
-            // Comparisons between integers are always known.
-            (Scalar::Int(_), Scalar::Int(_)) => a != b,
+            (Scalar::Int { .. }, Scalar::Int { .. }) => {
+                if a == b {
+                    1
+                } else {
+                    0
+                }
+            }
             // Comparisons of abstract pointers with null pointers are known if the pointer
             // is in bounds, because if they are in bounds, the pointer can't be null.
             // Inequality with integers other than null can never be known for sure.
             (Scalar::Int(int), ptr @ Scalar::Ptr(..))
-            | (ptr @ Scalar::Ptr(..), Scalar::Int(int)) => {
-                int.is_null() && !self.scalar_may_be_null(ptr)?
+            | (ptr @ Scalar::Ptr(..), Scalar::Int(int))
+                if int.is_null() && !self.scalar_may_be_null(ptr)? =>
+            {
+                0
             }
-            // FIXME: return `true` for at least some comparisons where we can reliably
+            // Equality with integers can never be known for sure.
+            (Scalar::Int { .. }, Scalar::Ptr(..)) | (Scalar::Ptr(..), Scalar::Int { .. }) => 2,
+            // FIXME: return a `1` for when both sides are the same pointer, *except* that
+            // some things (like functions and vtables) do not have stable addresses
+            // so we need to be careful around them (see e.g. #73722).
+            // FIXME: return `0` for at least some comparisons where we can reliably
             // determine the result of runtime inequality tests at compile-time.
             // Examples include comparison of addresses in different static items.
-            (Scalar::Ptr(..), Scalar::Ptr(..)) => false,
+            (Scalar::Ptr(..), Scalar::Ptr(..)) => 2,
         })
     }
 }
@@ -343,15 +330,11 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
             throw_unsup_format!("intrinsic `{intrinsic_name}` is not supported at compile-time");
         };
         match intrinsic_name {
-            sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {
+            sym::ptr_guaranteed_cmp => {
                 let a = ecx.read_scalar(&args[0])?;
                 let b = ecx.read_scalar(&args[1])?;
-                let cmp = if intrinsic_name == sym::ptr_guaranteed_eq {
-                    ecx.guaranteed_eq(a, b)?
-                } else {
-                    ecx.guaranteed_ne(a, b)?
-                };
-                ecx.write_scalar(Scalar::from_bool(cmp), dest)?;
+                let cmp = ecx.guaranteed_cmp(a, b)?;
+                ecx.write_scalar(Scalar::from_u8(cmp), dest)?;
             }
             sym::const_allocate => {
                 let size = ecx.read_scalar(&args[0])?.to_machine_usize(ecx)?;
diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs
index d9c4ae4d53f9..1c33e7845cb0 100644
--- a/compiler/rustc_const_eval/src/const_eval/mod.rs
+++ b/compiler/rustc_const_eval/src/const_eval/mod.rs
@@ -100,10 +100,10 @@ pub(crate) fn try_destructure_mir_constant<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     val: mir::ConstantKind<'tcx>,
-) -> InterpResult<'tcx, mir::DestructuredMirConstant<'tcx>> {
+) -> InterpResult<'tcx, mir::DestructuredConstant<'tcx>> {
     trace!("destructure_mir_constant: {:?}", val);
     let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
-    let op = ecx.mir_const_to_op(&val, None)?;
+    let op = ecx.const_to_op(&val, None)?;
 
     // We go to `usize` as we cannot allocate anything bigger anyway.
     let (field_count, variant, down) = match val.ty().kind() {
@@ -129,7 +129,7 @@ pub(crate) fn try_destructure_mir_constant<'tcx>(
         .collect::<InterpResult<'tcx, Vec<_>>>()?;
     let fields = tcx.arena.alloc_from_iter(fields_iter);
 
-    Ok(mir::DestructuredMirConstant { variant, fields })
+    Ok(mir::DestructuredConstant { variant, fields })
 }
 
 #[instrument(skip(tcx), level = "debug")]
@@ -139,7 +139,7 @@ pub(crate) fn deref_mir_constant<'tcx>(
     val: mir::ConstantKind<'tcx>,
 ) -> mir::ConstantKind<'tcx> {
     let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
-    let op = ecx.mir_const_to_op(&val, None).unwrap();
+    let op = ecx.const_to_op(&val, None).unwrap();
     let mplace = ecx.deref_operand(&op).unwrap();
     if let Some(alloc_id) = mplace.ptr.provenance {
         assert_eq!(
diff --git a/compiler/rustc_const_eval/src/const_eval/valtrees.rs b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
index 373b139c86e4..a964fe8465ee 100644
--- a/compiler/rustc_const_eval/src/const_eval/valtrees.rs
+++ b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
@@ -97,7 +97,7 @@ pub(crate) fn const_to_valtree_inner<'tcx>(
         }
 
         // Raw pointers are not allowed in type level constants, as we cannot properly test them for
-        // equality at compile-time (see `ptr_guaranteed_eq`/`_ne`).
+        // equality at compile-time (see `ptr_guaranteed_cmp`).
         // Technically we could allow function pointers (represented as `ty::Instance`), but this is not guaranteed to
         // agree with runtime equality tests.
         ty::FnPtr(_) | ty::RawPtr(_) => Err(ValTreeCreationError::NonSupportedType),
@@ -204,7 +204,7 @@ fn get_info_on_unsized_field<'tcx>(
     (unsized_inner_ty, num_elems)
 }
 
-#[instrument(skip(ecx), level = "debug")]
+#[instrument(skip(ecx), level = "debug", ret)]
 fn create_pointee_place<'tcx>(
     ecx: &mut CompileTimeEvalContext<'tcx, 'tcx>,
     ty: Ty<'tcx>,
@@ -237,14 +237,11 @@ fn create_pointee_place<'tcx>(
         let ptr = ecx.allocate_ptr(size, align, MemoryKind::Stack).unwrap();
         debug!(?ptr);
 
-        let place = MPlaceTy::from_aligned_ptr_with_meta(
+        MPlaceTy::from_aligned_ptr_with_meta(
             ptr.into(),
             layout,
             MemPlaceMeta::Meta(Scalar::from_machine_usize(num_elems as u64, &tcx)),
-        );
-        debug!(?place);
-
-        place
+        )
     } else {
         create_mplace_from_layout(ecx, ty)
     }
@@ -253,7 +250,7 @@ fn create_pointee_place<'tcx>(
 /// Converts a `ValTree` to a `ConstValue`, which is needed after mir
 /// construction has finished.
 // FIXME Merge `valtree_to_const_value` and `valtree_into_mplace` into one function
-#[instrument(skip(tcx), level = "debug")]
+#[instrument(skip(tcx), level = "debug", ret)]
 pub fn valtree_to_const_value<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env_ty: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,
@@ -294,7 +291,7 @@ pub fn valtree_to_const_value<'tcx>(
             dump_place(&ecx, place.into());
             intern_const_alloc_recursive(&mut ecx, InternKind::Constant, &place).unwrap();
 
-            let const_val = match ty.kind() {
+            match ty.kind() {
                 ty::Ref(_, _, _) => {
                     let ref_place = place.to_ref(&tcx);
                     let imm =
@@ -303,10 +300,7 @@ pub fn valtree_to_const_value<'tcx>(
                     op_to_const(&ecx, &imm.into())
                 }
                 _ => op_to_const(&ecx, &place.into()),
-            };
-            debug!(?const_val);
-
-            const_val
+            }
         }
         ty::Never
         | ty::Error(_)
diff --git a/compiler/rustc_const_eval/src/errors.rs b/compiler/rustc_const_eval/src/errors.rs
index c3547cb3abdf..c6cb7a8b961f 100644
--- a/compiler/rustc_const_eval/src/errors.rs
+++ b/compiler/rustc_const_eval/src/errors.rs
@@ -1,8 +1,8 @@
 use rustc_hir::ConstContext;
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unstable_in_stable)]
 pub(crate) struct UnstableInStable {
     pub gate: String,
@@ -21,14 +21,14 @@ pub(crate) struct UnstableInStable {
     pub attr_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::thread_local_access, code = "E0625")]
 pub(crate) struct NonConstOpErr {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::static_access, code = "E0013")]
 #[help]
 pub(crate) struct StaticAccessErr {
@@ -40,7 +40,7 @@ pub(crate) struct StaticAccessErr {
     pub teach: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::raw_ptr_to_int)]
 #[note]
 #[note(const_eval::note2)]
@@ -49,7 +49,7 @@ pub(crate) struct RawPtrToIntErr {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::raw_ptr_comparison)]
 #[note]
 pub(crate) struct RawPtrComparisonErr {
@@ -57,14 +57,14 @@ pub(crate) struct RawPtrComparisonErr {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::panic_non_str)]
 pub(crate) struct PanicNonStrErr {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::mut_deref, code = "E0658")]
 pub(crate) struct MutDerefErr {
     #[primary_span]
@@ -72,7 +72,7 @@ pub(crate) struct MutDerefErr {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::transient_mut_borrow, code = "E0658")]
 pub(crate) struct TransientMutBorrowErr {
     #[primary_span]
@@ -80,7 +80,7 @@ pub(crate) struct TransientMutBorrowErr {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::transient_mut_borrow_raw, code = "E0658")]
 pub(crate) struct TransientMutBorrowErrRaw {
     #[primary_span]
@@ -88,7 +88,7 @@ pub(crate) struct TransientMutBorrowErrRaw {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::max_num_nodes_in_const)]
 pub(crate) struct MaxNumNodesInConstErr {
     #[primary_span]
@@ -96,7 +96,7 @@ pub(crate) struct MaxNumNodesInConstErr {
     pub global_const_id: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unallowed_fn_pointer_call)]
 pub(crate) struct UnallowedFnPointerCall {
     #[primary_span]
@@ -104,7 +104,7 @@ pub(crate) struct UnallowedFnPointerCall {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unstable_const_fn)]
 pub(crate) struct UnstableConstFn {
     #[primary_span]
@@ -112,7 +112,7 @@ pub(crate) struct UnstableConstFn {
     pub def_path: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unallowed_mutable_refs, code = "E0764")]
 pub(crate) struct UnallowedMutableRefs {
     #[primary_span]
@@ -122,7 +122,7 @@ pub(crate) struct UnallowedMutableRefs {
     pub teach: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unallowed_mutable_refs_raw, code = "E0764")]
 pub(crate) struct UnallowedMutableRefsRaw {
     #[primary_span]
@@ -131,7 +131,7 @@ pub(crate) struct UnallowedMutableRefsRaw {
     #[note(const_eval::teach_note)]
     pub teach: Option<()>,
 }
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::non_const_fmt_macro_call, code = "E0015")]
 pub(crate) struct NonConstFmtMacroCall {
     #[primary_span]
@@ -139,7 +139,7 @@ pub(crate) struct NonConstFmtMacroCall {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::non_const_fn_call, code = "E0015")]
 pub(crate) struct NonConstFnCall {
     #[primary_span]
@@ -148,7 +148,7 @@ pub(crate) struct NonConstFnCall {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unallowed_op_in_const_context)]
 pub(crate) struct UnallowedOpInConstContext {
     #[primary_span]
@@ -156,7 +156,7 @@ pub(crate) struct UnallowedOpInConstContext {
     pub msg: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unallowed_heap_allocations, code = "E0010")]
 pub(crate) struct UnallowedHeapAllocations {
     #[primary_span]
@@ -167,7 +167,7 @@ pub(crate) struct UnallowedHeapAllocations {
     pub teach: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::unallowed_inline_asm, code = "E0015")]
 pub(crate) struct UnallowedInlineAsm {
     #[primary_span]
@@ -175,7 +175,7 @@ pub(crate) struct UnallowedInlineAsm {
     pub kind: ConstContext,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::interior_mutable_data_refer, code = "E0492")]
 pub(crate) struct InteriorMutableDataRefer {
     #[primary_span]
@@ -188,7 +188,7 @@ pub(crate) struct InteriorMutableDataRefer {
     pub teach: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(const_eval::interior_mutability_borrow)]
 pub(crate) struct InteriorMutabilityBorrow {
     #[primary_span]
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index 07dbd80e077f..cbe98548025b 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -108,6 +108,20 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     _ => span_bug!(self.cur_span(), "closure fn pointer on {:?}", src.layout.ty),
                 }
             }
+
+            DynStar => {
+                if let ty::Dynamic(data, _, ty::DynStar) = cast_ty.kind() {
+                    // Initial cast from sized to dyn trait
+                    let vtable = self.get_vtable_ptr(src.layout.ty, data.principal())?;
+                    let vtable = Scalar::from_maybe_pointer(vtable, self);
+                    let data = self.read_immediate(src)?.to_scalar();
+                    let _assert_pointer_sized = data.to_pointer(self)?;
+                    let val = Immediate::ScalarPair(data, vtable);
+                    self.write_immediate(val, dest)?;
+                } else {
+                    bug!()
+                }
+            }
         }
         Ok(())
     }
@@ -312,7 +326,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let new_vptr = self.get_vtable_ptr(ty, data_b.principal())?;
                 self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest)
             }
-            (_, &ty::Dynamic(ref data, _)) => {
+            (_, &ty::Dynamic(ref data, _, ty::Dyn)) => {
                 // Initial cast from sized to dyn trait
                 let vtable = self.get_vtable_ptr(src_pointee_ty, data.principal())?;
                 let ptr = self.read_scalar(src)?;
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index d37eaeed095a..bdebfbb3ff51 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -683,11 +683,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.stack_mut().push(frame);
 
         // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check).
-        for const_ in &body.required_consts {
-            let span = const_.span;
-            let const_ =
-                self.subst_from_current_frame_and_normalize_erasing_regions(const_.literal)?;
-            self.mir_const_to_op(&const_, None).map_err(|err| {
+        for ct in &body.required_consts {
+            let span = ct.span;
+            let ct = self.subst_from_current_frame_and_normalize_erasing_regions(ct.literal)?;
+            self.const_to_op(&ct, None).map_err(|err| {
                 // If there was an error, set the span of the current frame to this constant.
                 // Avoiding doing this when evaluation succeeds.
                 self.frame_mut().loc = Err(span);
@@ -929,11 +928,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     }
 
     #[must_use]
-    pub fn generate_stacktrace(&self) -> Vec<FrameInfo<'tcx>> {
+    pub fn generate_stacktrace_from_stack(
+        stack: &[Frame<'mir, 'tcx, M::Provenance, M::FrameExtra>],
+    ) -> Vec<FrameInfo<'tcx>> {
         let mut frames = Vec::new();
         // This deliberately does *not* honor `requires_caller_location` since it is used for much
         // more than just panics.
-        for frame in self.stack().iter().rev() {
+        for frame in stack.iter().rev() {
             let lint_root = frame.current_source_info().and_then(|source_info| {
                 match &frame.body.source_scopes[source_info.scope].local_data {
                     mir::ClearCrossCrate::Set(data) => Some(data.lint_root),
@@ -947,6 +948,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         trace!("generate stacktrace: {:#?}", frames);
         frames
     }
+
+    #[must_use]
+    pub fn generate_stacktrace(&self) -> Vec<FrameInfo<'tcx>> {
+        Self::generate_stacktrace_from_stack(self.stack())
+    }
 }
 
 #[doc(hidden)]
diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs
index 66ab3f15716f..24dbc769529c 100644
--- a/compiler/rustc_const_eval/src/interpret/intern.rs
+++ b/compiler/rustc_const_eval/src/interpret/intern.rs
@@ -334,7 +334,7 @@ pub enum InternKind {
 /// tracks where in the value we are and thus can show much better error messages.
 /// Any errors here would anyway be turned into `const_err` lints, whereas validation failures
 /// are hard errors.
-#[tracing::instrument(level = "debug", skip(ecx))]
+#[instrument(level = "debug", skip(ecx))]
 pub fn intern_const_alloc_recursive<
     'mir,
     'tcx: 'mir,
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index a8ec8447f64a..8637d6a7767e 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -8,7 +8,7 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::mir::{
     self,
     interpret::{ConstValue, GlobalId, InterpResult, PointerArithmetic, Scalar},
-    BinOp,
+    BinOp, NonDivergingIntrinsic,
 };
 use rustc_middle::ty;
 use rustc_middle::ty::layout::LayoutOf as _;
@@ -79,9 +79,9 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
             ty::Projection(_)
             | ty::Opaque(_, _)
             | ty::Param(_)
-            | ty::Bound(_, _)
             | ty::Placeholder(_)
             | ty::Infer(_) => throw_inval!(TooGeneric),
+            ty::Bound(_, _) => bug!("bound ty during ctfe"),
             ty::Bool
             | ty::Char
             | ty::Int(_)
@@ -95,7 +95,7 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
             | ty::Ref(_, _, _)
             | ty::FnDef(_, _)
             | ty::FnPtr(_)
-            | ty::Dynamic(_, _)
+            | ty::Dynamic(_, _, _)
             | ty::Closure(_, _)
             | ty::Generator(_, _, _)
             | ty::GeneratorWitness(_)
@@ -320,7 +320,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let (a_offset, b_offset) =
                     match (self.ptr_try_get_alloc_id(a), self.ptr_try_get_alloc_id(b)) {
                         (Err(a), Err(b)) => {
-                            // Neither poiner points to an allocation.
+                            // Neither pointer points to an allocation.
                             // If these are inequal or null, this *will* fail the deref check below.
                             (a, b)
                         }
@@ -506,12 +506,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // These just return their argument
                 self.copy_op(&args[0], dest, /*allow_transmute*/ false)?;
             }
-            sym::assume => {
-                let cond = self.read_scalar(&args[0])?.to_bool()?;
-                if !cond {
-                    throw_ub_format!("`assume` intrinsic called with `false`");
-                }
-            }
             sym::raw_eq => {
                 let result = self.raw_eq_intrinsic(&args[0], &args[1])?;
                 self.write_scalar(result, dest)?;
@@ -536,6 +530,32 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(true)
     }
 
+    pub(super) fn emulate_nondiverging_intrinsic(
+        &mut self,
+        intrinsic: &NonDivergingIntrinsic<'tcx>,
+    ) -> InterpResult<'tcx> {
+        match intrinsic {
+            NonDivergingIntrinsic::Assume(op) => {
+                let op = self.eval_operand(op, None)?;
+                let cond = self.read_scalar(&op)?.to_bool()?;
+                if !cond {
+                    throw_ub_format!("`assume` called with `false`");
+                }
+                Ok(())
+            }
+            NonDivergingIntrinsic::CopyNonOverlapping(mir::CopyNonOverlapping {
+                count,
+                src,
+                dst,
+            }) => {
+                let src = self.eval_operand(src, None)?;
+                let dst = self.eval_operand(dst, None)?;
+                let count = self.eval_operand(count, None)?;
+                self.copy_intrinsic(&src, &dst, &count, /* nonoverlapping */ true)
+            }
+        }
+    }
+
     pub fn exact_div(
         &mut self,
         a: &ImmTy<'tcx, M::Provenance>,
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
index 91f4f0425172..0e3867557ada 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
@@ -4,7 +4,6 @@ use rustc_ast::Mutability;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::mir::TerminatorKind;
 use rustc_middle::ty::layout::LayoutOf;
-use rustc_middle::ty::subst::Subst;
 use rustc_span::{Span, Symbol};
 
 use crate::interpret::{
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
index f9847742f088..7e4c5fcb031b 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
@@ -48,7 +48,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             | ty::FnPtr(_)
             | ty::Never
             | ty::Tuple(_)
-            | ty::Dynamic(_, _) => self.pretty_print_type(ty),
+            | ty::Dynamic(_, _, _) => self.pretty_print_type(ty),
 
             // Placeholders (all printed as `_` to uniformize them).
             ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => {
diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs
index 5aabb14fba88..530e252b7c07 100644
--- a/compiler/rustc_const_eval/src/interpret/machine.rs
+++ b/compiler/rustc_const_eval/src/interpret/machine.rs
@@ -6,6 +6,7 @@ use std::borrow::{Borrow, Cow};
 use std::fmt::Debug;
 use std::hash::Hash;
 
+use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_middle::mir;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::def_id::DefId;
@@ -323,6 +324,15 @@ pub trait Machine<'mir, 'tcx>: Sized {
         kind: Option<MemoryKind<Self::MemoryKind>>,
     ) -> InterpResult<'tcx, Cow<'b, Allocation<Self::Provenance, Self::AllocExtra>>>;
 
+    fn eval_inline_asm(
+        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        _template: &'tcx [InlineAsmTemplatePiece],
+        _operands: &[mir::InlineAsmOperand<'tcx>],
+        _options: InlineAsmOptions,
+    ) -> InterpResult<'tcx> {
+        throw_unsup_format!("inline assembly is not supported")
+    }
+
     /// Hook for performing extra checks on a memory read access.
     ///
     /// Takes read-only access to the allocation so we can keep all the memory read
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 69dbc9592fa8..ed155fbfef08 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -437,7 +437,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         msg,
                     })
                 }
-                // Ensure we never consider the null pointer dereferencable.
+                // Ensure we never consider the null pointer dereferenceable.
                 if M::Provenance::OFFSET_IS_ADDR {
                     assert_ne!(ptr.addr(), Size::ZERO);
                 }
@@ -914,7 +914,7 @@ impl<'tcx, 'a, Prov: Provenance, Extra> AllocRefMut<'a, 'tcx, Prov, Extra> {
         self.write_scalar(alloc_range(offset, self.tcx.data_layout().pointer_size), val)
     }
 
-    /// Mark the entire referenced range as uninitalized
+    /// Mark the entire referenced range as uninitialized
     pub fn write_uninit(&mut self) -> InterpResult<'tcx> {
         Ok(self
             .alloc
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index 35c2cf8102dc..510adde62962 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -534,7 +534,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // * During ConstProp, with `TooGeneric` or since the `required_consts` were not all
                 //   checked yet.
                 // * During CTFE, since promoteds in `const`/`static` initializer bodies can fail.
-                self.mir_const_to_op(&val, layout)?
+                self.const_to_op(&val, layout)?
             }
         };
         trace!("{:?}: {:?}", mir_op, *op);
@@ -549,43 +549,47 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         ops.iter().map(|op| self.eval_operand(op, None)).collect()
     }
 
-    // Used when the miri-engine runs into a constant and for extracting information from constants
-    // in patterns via the `const_eval` module
-    /// The `val` and `layout` are assumed to already be in our interpreter
-    /// "universe" (param_env).
     pub fn const_to_op(
-        &self,
-        c: ty::Const<'tcx>,
-        layout: Option<TyAndLayout<'tcx>>,
-    ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
-        match c.kind() {
-            ty::ConstKind::Param(_) | ty::ConstKind::Bound(..) => throw_inval!(TooGeneric),
-            ty::ConstKind::Error(DelaySpanBugEmitted { reported, .. }) => {
-                throw_inval!(AlreadyReported(reported))
-            }
-            ty::ConstKind::Unevaluated(uv) => {
-                let instance = self.resolve(uv.def, uv.substs)?;
-                Ok(self.eval_to_allocation(GlobalId { instance, promoted: uv.promoted })?.into())
-            }
-            ty::ConstKind::Infer(..) | ty::ConstKind::Placeholder(..) => {
-                span_bug!(self.cur_span(), "const_to_op: Unexpected ConstKind {:?}", c)
-            }
-            ty::ConstKind::Value(valtree) => {
-                let ty = c.ty();
-                let const_val = self.tcx.valtree_to_const_val((ty, valtree));
-                self.const_val_to_op(const_val, ty, layout)
-            }
-        }
-    }
-
-    pub fn mir_const_to_op(
         &self,
         val: &mir::ConstantKind<'tcx>,
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
         match val {
-            mir::ConstantKind::Ty(ct) => self.const_to_op(*ct, layout),
+            mir::ConstantKind::Ty(ct) => {
+                match ct.kind() {
+                    ty::ConstKind::Param(_) | ty::ConstKind::Placeholder(..) => {
+                        throw_inval!(TooGeneric)
+                    }
+                    ty::ConstKind::Error(DelaySpanBugEmitted { reported, .. }) => {
+                        throw_inval!(AlreadyReported(reported))
+                    }
+                    ty::ConstKind::Unevaluated(uv) => {
+                        // NOTE: We evaluate to a `ValTree` here as a check to ensure
+                        // we're working with valid constants, even though we never need it.
+                        let instance = self.resolve(uv.def, uv.substs)?;
+                        let cid = GlobalId { instance, promoted: None };
+                        let _valtree = self
+                            .tcx
+                            .eval_to_valtree(self.param_env.and(cid))?
+                            .unwrap_or_else(|| bug!("unable to create ValTree for {uv:?}"));
+
+                        Ok(self.eval_to_allocation(cid)?.into())
+                    }
+                    ty::ConstKind::Bound(..) | ty::ConstKind::Infer(..) => {
+                        span_bug!(self.cur_span(), "unexpected ConstKind in ctfe: {ct:?}")
+                    }
+                    ty::ConstKind::Value(valtree) => {
+                        let ty = ct.ty();
+                        let const_val = self.tcx.valtree_to_const_val((ty, valtree));
+                        self.const_val_to_op(const_val, ty, layout)
+                    }
+                }
+            }
             mir::ConstantKind::Val(val, ty) => self.const_val_to_op(*val, *ty, layout),
+            mir::ConstantKind::Unevaluated(uv, _) => {
+                let instance = self.resolve(uv.def, uv.substs)?;
+                Ok(self.eval_to_allocation(GlobalId { instance, promoted: uv.promoted })?.into())
+            }
         }
     }
 
@@ -718,7 +722,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // Return the cast value, and the index.
                 (discr_val, index.0)
             }
-            TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
+            TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start } => {
                 let tag_val = tag_val.to_scalar();
                 // Compute the variant this niche value/"tag" corresponds to. With niche layout,
                 // discriminant (encoded in niche/tag) and variant index are the same.
@@ -736,7 +740,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         if !ptr_valid {
                             throw_ub!(InvalidTag(dbg_val))
                         }
-                        dataful_variant
+                        untagged_variant
                     }
                     Ok(tag_bits) => {
                         let tag_bits = tag_bits.assert_bits(tag_layout.size);
@@ -766,7 +770,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                             assert!(usize::try_from(variant_index).unwrap() < variants_len);
                             VariantIdx::from_u32(variant_index)
                         } else {
-                            dataful_variant
+                            untagged_variant
                         }
                     }
                 };
@@ -785,8 +789,8 @@ mod size_asserts {
     use super::*;
     use rustc_data_structures::static_assert_size;
     // These are in alphabetical order, which is easy to maintain.
-    static_assert_size!(Immediate, 56);
-    static_assert_size!(ImmTy<'_>, 72);
-    static_assert_size!(Operand, 64);
-    static_assert_size!(OpTy<'_>, 88);
+    static_assert_size!(Immediate, 48);
+    static_assert_size!(ImmTy<'_>, 64);
+    static_assert_size!(Operand, 56);
+    static_assert_size!(OpTy<'_>, 80);
 }
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index a03b0dfb6038..7a01b85381a3 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -280,7 +280,7 @@ impl<'tcx, Prov: Provenance> PlaceTy<'tcx, Prov> {
 
     #[inline(always)]
     #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980)
-    pub fn assert_mem_place(self) -> MPlaceTy<'tcx, Prov> {
+    pub fn assert_mem_place(&self) -> MPlaceTy<'tcx, Prov> {
         self.try_as_mplace().unwrap()
     }
 }
@@ -817,7 +817,7 @@ where
             }
             abi::Variants::Multiple {
                 tag_encoding:
-                    TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start },
+                    TagEncoding::Niche { untagged_variant, ref niche_variants, niche_start },
                 tag: tag_layout,
                 tag_field,
                 ..
@@ -825,7 +825,7 @@ where
                 // No need to validate that the discriminant here because the
                 // `TyAndLayout::for_variant()` call earlier already checks the variant is valid.
 
-                if variant_index != dataful_variant {
+                if variant_index != untagged_variant {
                     let variants_start = niche_variants.start().as_u32();
                     let variant_index_relative = variant_index
                         .as_u32()
@@ -890,6 +890,6 @@ mod size_asserts {
     static_assert_size!(MemPlaceMeta, 24);
     static_assert_size!(MemPlace, 40);
     static_assert_size!(MPlaceTy<'_>, 64);
-    static_assert_size!(Place, 48);
-    static_assert_size!(PlaceTy<'_>, 72);
+    static_assert_size!(Place, 40);
+    static_assert_size!(PlaceTy<'_>, 64);
 }
diff --git a/compiler/rustc_const_eval/src/interpret/projection.rs b/compiler/rustc_const_eval/src/interpret/projection.rs
index 67dc9011ea20..6b2e2bb8aca8 100644
--- a/compiler/rustc_const_eval/src/interpret/projection.rs
+++ b/compiler/rustc_const_eval/src/interpret/projection.rs
@@ -1,6 +1,6 @@
 //! This file implements "place projections"; basically a symmetric API for 3 types: MPlaceTy, OpTy, PlaceTy.
 //!
-//! OpTy and PlaceTy genrally work by "let's see if we are actually an MPlaceTy, and do something custom if not".
+//! OpTy and PlaceTy generally work by "let's see if we are actually an MPlaceTy, and do something custom if not".
 //! For PlaceTy, the custom thing is basically always to call `force_allocation` and then use the MPlaceTy logic anyway.
 //! For OpTy, the custom thing on field pojections has to be pretty clever (since `Operand::Immediate` can have fields),
 //! but for array/slice operations it only has to worry about `Operand::Uninit`. That makes the value part trivial,
@@ -350,6 +350,11 @@ where
     ) -> InterpResult<'tcx, PlaceTy<'tcx, M::Provenance>> {
         use rustc_middle::mir::ProjectionElem::*;
         Ok(match proj_elem {
+            OpaqueCast(ty) => {
+                let mut place = base.clone();
+                place.layout = self.layout_of(ty)?;
+                place
+            }
             Field(field, _) => self.place_field(base, field.index())?,
             Downcast(_, variant) => self.place_downcast(base, variant)?,
             Deref => self.deref_operand(&self.place_to_op(base)?)?.into(),
@@ -374,6 +379,11 @@ where
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
         use rustc_middle::mir::ProjectionElem::*;
         Ok(match proj_elem {
+            OpaqueCast(ty) => {
+                let mut op = base.clone();
+                op.layout = self.layout_of(ty)?;
+                op
+            }
             Field(field, _) => self.operand_field(base, field.index())?,
             Downcast(_, variant) => self.operand_downcast(base, variant)?,
             Deref => self.deref_operand(base)?.into(),
diff --git a/compiler/rustc_const_eval/src/interpret/step.rs b/compiler/rustc_const_eval/src/interpret/step.rs
index 6b827149f505..c6e04cbfb6bf 100644
--- a/compiler/rustc_const_eval/src/interpret/step.rs
+++ b/compiler/rustc_const_eval/src/interpret/step.rs
@@ -114,13 +114,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 M::retag(self, *kind, &dest)?;
             }
 
-            // Call CopyNonOverlapping
-            CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping { src, dst, count }) => {
-                let src = self.eval_operand(src, None)?;
-                let dst = self.eval_operand(dst, None)?;
-                let count = self.eval_operand(count, None)?;
-                self.copy_intrinsic(&src, &dst, &count, /* nonoverlapping */ true)?;
-            }
+            Intrinsic(box ref intrinsic) => self.emulate_nondiverging_intrinsic(intrinsic)?,
 
             // Statements we do not track.
             AscribeUserType(..) => {}
diff --git a/compiler/rustc_const_eval/src/interpret/terminator.rs b/compiler/rustc_const_eval/src/interpret/terminator.rs
index a71a5d4b833c..50a82aa0e72c 100644
--- a/compiler/rustc_const_eval/src/interpret/terminator.rs
+++ b/compiler/rustc_const_eval/src/interpret/terminator.rs
@@ -1,5 +1,6 @@
 use std::borrow::Cow;
 
+use rustc_ast::ast::InlineAsmOptions;
 use rustc_middle::ty::layout::{FnAbiOf, LayoutOf};
 use rustc_middle::ty::Instance;
 use rustc_middle::{
@@ -166,8 +167,16 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 terminator.kind
             ),
 
-            // Inline assembly can't be interpreted.
-            InlineAsm { .. } => throw_unsup_format!("inline assembly is not supported"),
+            InlineAsm { template, ref operands, options, destination, .. } => {
+                M::eval_inline_asm(self, template, operands, options)?;
+                if options.contains(InlineAsmOptions::NORETURN) {
+                    throw_ub_format!("returned from noreturn inline assembly");
+                }
+                self.go_to_block(
+                    destination
+                        .expect("InlineAsm terminators without noreturn must have a destination"),
+                )
+            }
         }
 
         Ok(())
@@ -217,7 +226,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // When comparing the PassMode, we have to be smart about comparing the attributes.
         let arg_attr_compat = |a1: &ArgAttributes, a2: &ArgAttributes| {
             // There's only one regular attribute that matters for the call ABI: InReg.
-            // Everything else is things like noalias, dereferencable, nonnull, ...
+            // Everything else is things like noalias, dereferenceable, nonnull, ...
             // (This also applies to pointee_size, pointee_align.)
             if a1.regular.contains(ArgAttribute::InReg) != a2.regular.contains(ArgAttribute::InReg)
             {
@@ -556,7 +565,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     .tcx
                     .struct_tail_erasing_lifetimes(receiver_place.layout.ty, self.param_env);
                 let ty::Dynamic(data, ..) = receiver_tail.kind() else {
-                    span_bug!(self.cur_span(), "dyanmic call on non-`dyn` type {}", receiver_tail)
+                    span_bug!(self.cur_span(), "dynamic call on non-`dyn` type {}", receiver_tail)
                 };
 
                 // Get the required information from the vtable.
diff --git a/compiler/rustc_const_eval/src/interpret/traits.rs b/compiler/rustc_const_eval/src/interpret/traits.rs
index b3a511d5a492..cab23b7241ff 100644
--- a/compiler/rustc_const_eval/src/interpret/traits.rs
+++ b/compiler/rustc_const_eval/src/interpret/traits.rs
@@ -32,7 +32,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(vtable_ptr.into())
     }
 
-    /// Returns a high-level representation of the entires of the given vtable.
+    /// Returns a high-level representation of the entries of the given vtable.
     pub fn get_vtable_entries(
         &self,
         vtable: Pointer<Option<M::Provenance>>,
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 0382e2d5805a..14aaee6ac3f9 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -5,7 +5,7 @@
 //! to be const-safe.
 
 use std::convert::TryFrom;
-use std::fmt::Write;
+use std::fmt::{Display, Write};
 use std::num::NonZeroUsize;
 
 use rustc_ast::Mutability;
@@ -311,7 +311,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
     fn read_immediate(
         &self,
         op: &OpTy<'tcx, M::Provenance>,
-        expected: &str,
+        expected: impl Display,
     ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         Ok(try_validation!(
             self.ecx.read_immediate(op),
@@ -323,7 +323,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
     fn read_scalar(
         &self,
         op: &OpTy<'tcx, M::Provenance>,
-        expected: &str,
+        expected: impl Display,
     ) -> InterpResult<'tcx, Scalar<M::Provenance>> {
         Ok(self.read_immediate(op, expected)?.to_scalar())
     }
@@ -368,7 +368,8 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
         value: &OpTy<'tcx, M::Provenance>,
         kind: &str,
     ) -> InterpResult<'tcx> {
-        let place = self.ecx.ref_to_mplace(&self.read_immediate(value, &format!("a {kind}"))?)?;
+        let place =
+            self.ecx.ref_to_mplace(&self.read_immediate(value, format_args!("a {kind}"))?)?;
         // Handle wide pointers.
         // Check metadata early, for better diagnostics
         if place.layout.is_unsized() {
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index 72ac6af685dc..7c4c7db1035b 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -10,7 +10,6 @@ Rust MIR: a lowered representation of Rust.
 #![feature(decl_macro)]
 #![feature(exact_size_is_empty)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(slice_ptr_get)]
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index cbfdb47dd1a4..b0dcbf76b01b 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -13,8 +13,11 @@ use rustc_middle::ty::{self, adjustment::PointerCast, Instance, InstanceDef, Ty,
 use rustc_middle::ty::{Binder, TraitPredicate, TraitRef, TypeVisitable};
 use rustc_mir_dataflow::{self, Analysis};
 use rustc_span::{sym, Span, Symbol};
-use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
-use rustc_trait_selection::traits::SelectionContext;
+use rustc_trait_selection::infer::InferCtxtExt;
+use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _;
+use rustc_trait_selection::traits::{
+    self, ObligationCauseCode, SelectionContext, TraitEngine, TraitEngineExt,
+};
 
 use std::mem;
 use std::ops::Deref;
@@ -546,6 +549,10 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 // Since no pointer can ever get exposed (rejected above), this is easy to support.
             }
 
+            Rvalue::Cast(CastKind::DynStar, _, _) => {
+                unimplemented!()
+            }
+
             Rvalue::Cast(CastKind::Misc, _, _) => {}
 
             Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, _) => {}
@@ -652,6 +659,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
             ProjectionElem::ConstantIndex { .. }
             | ProjectionElem::Downcast(..)
+            | ProjectionElem::OpaqueCast(..)
             | ProjectionElem::Subslice { .. }
             | ProjectionElem::Field(..)
             | ProjectionElem::Index(_) => {}
@@ -678,7 +686,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
             | StatementKind::Retag { .. }
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
-            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Intrinsic(..)
             | StatementKind::Nop => {}
         }
     }
@@ -734,6 +742,43 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                         selcx.select(&obligation)
                     });
 
+                    // do a well-formedness check on the trait method being called. This is because typeck only does a
+                    // "non-const" check. This is required for correctness here.
+                    tcx.infer_ctxt().enter(|infcx| {
+                        let mut fulfill_cx = <dyn TraitEngine<'_>>::new(infcx.tcx);
+                        let predicates = tcx.predicates_of(callee).instantiate(tcx, substs);
+                        let hir_id = tcx
+                            .hir()
+                            .local_def_id_to_hir_id(self.body.source.def_id().expect_local());
+                        let cause = || {
+                            ObligationCause::new(
+                                terminator.source_info.span,
+                                hir_id,
+                                ObligationCauseCode::ItemObligation(callee),
+                            )
+                        };
+                        let normalized = infcx.partially_normalize_associated_types_in(
+                            cause(),
+                            param_env,
+                            predicates,
+                        );
+
+                        for p in normalized.obligations {
+                            fulfill_cx.register_predicate_obligation(&infcx, p);
+                        }
+                        for obligation in traits::predicates_for_generics(
+                            |_, _| cause(),
+                            self.param_env,
+                            normalized.value,
+                        ) {
+                            fulfill_cx.register_predicate_obligation(&infcx, obligation);
+                        }
+                        let errors = fulfill_cx.select_all_or_error(&infcx);
+                        if !errors.is_empty() {
+                            infcx.report_fulfillment_errors(&errors, None, false);
+                        }
+                    });
+
                     match implsrc {
                         Ok(Some(ImplSource::Param(_, ty::BoundConstness::ConstIfConst))) => {
                             debug!(
@@ -964,7 +1009,10 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
                 if needs_non_const_drop {
                     self.check_op_spanned(
-                        ops::LiveDrop { dropped_at: Some(terminator.source_info.span) },
+                        ops::LiveDrop {
+                            dropped_at: Some(terminator.source_info.span),
+                            dropped_ty: ty_of_dropped_place,
+                        },
                         err_span,
                     );
                 }
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
index 5fb4bf638b34..b56b230201ed 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
@@ -422,10 +422,11 @@ impl<'tcx> NonConstOp<'tcx> for InlineAsm {
 }
 
 #[derive(Debug)]
-pub struct LiveDrop {
+pub struct LiveDrop<'tcx> {
     pub dropped_at: Option<Span>,
+    pub dropped_ty: Ty<'tcx>,
 }
-impl<'tcx> NonConstOp<'tcx> for LiveDrop {
+impl<'tcx> NonConstOp<'tcx> for LiveDrop<'tcx> {
     fn build_error(
         &self,
         ccx: &ConstCx<'_, 'tcx>,
@@ -435,9 +436,13 @@ impl<'tcx> NonConstOp<'tcx> for LiveDrop {
             ccx.tcx.sess,
             span,
             E0493,
-            "destructors cannot be evaluated at compile-time"
+            "destructor of `{}` cannot be evaluated at compile-time",
+            self.dropped_ty,
+        );
+        err.span_label(
+            span,
+            format!("the destructor for this type cannot be evaluated in {}s", ccx.const_kind()),
         );
-        err.span_label(span, format!("{}s cannot evaluate destructors", ccx.const_kind()));
         if let Some(span) = self.dropped_at {
             err.span_label(span, "value is dropped here");
         }
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs b/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs
index 4e210f66353f..d4570c598891 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs
@@ -1,6 +1,6 @@
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{self, BasicBlock, Location};
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_span::{symbol::sym, Span};
 
 use super::check::Qualifs;
@@ -58,9 +58,9 @@ impl<'mir, 'tcx> std::ops::Deref for CheckLiveDrops<'mir, 'tcx> {
     }
 }
 
-impl CheckLiveDrops<'_, '_> {
-    fn check_live_drop(&self, span: Span) {
-        ops::LiveDrop { dropped_at: None }.build_error(self.ccx, span).emit();
+impl<'tcx> CheckLiveDrops<'_, 'tcx> {
+    fn check_live_drop(&self, span: Span, dropped_ty: Ty<'tcx>) {
+        ops::LiveDrop { dropped_at: None, dropped_ty }.build_error(self.ccx, span).emit();
     }
 }
 
@@ -90,7 +90,7 @@ impl<'tcx> Visitor<'tcx> for CheckLiveDrops<'_, 'tcx> {
                 }
 
                 if dropped_place.is_indirect() {
-                    self.check_live_drop(terminator.source_info.span);
+                    self.check_live_drop(terminator.source_info.span, dropped_ty);
                     return;
                 }
 
@@ -101,7 +101,7 @@ impl<'tcx> Visitor<'tcx> for CheckLiveDrops<'_, 'tcx> {
                 if self.qualifs.needs_non_const_drop(self.ccx, dropped_place.local, location) {
                     // Use the span where the dropped local was declared for the error.
                     let span = self.body.local_decls[dropped_place.local].source_info.span;
-                    self.check_live_drop(span);
+                    self.check_live_drop(span, dropped_ty);
                 }
             }
 
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
index 45dadcfff2e5..60deb0abd344 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -5,6 +5,7 @@
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::LangItem;
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_middle::mir;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, subst::SubstsRef, AdtDef, Ty};
 use rustc_span::DUMMY_SP;
@@ -308,6 +309,7 @@ where
 
             ProjectionElem::Deref
             | ProjectionElem::Field(_, _)
+            | ProjectionElem::OpaqueCast(_)
             | ProjectionElem::ConstantIndex { .. }
             | ProjectionElem::Subslice { .. }
             | ProjectionElem::Downcast(_, _)
@@ -346,31 +348,36 @@ where
     };
 
     // Check the qualifs of the value of `const` items.
-    if let Some(ct) = constant.literal.const_for_ty() {
-        if let ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) = ct.kind()
-        {
-            // Use qualifs of the type for the promoted. Promoteds in MIR body should be possible
-            // only for `NeedsNonConstDrop` with precise drop checking. This is the only const
-            // check performed after the promotion. Verify that with an assertion.
-            assert!(promoted.is_none() || Q::ALLOW_PROMOTED);
-            // Don't peek inside trait associated constants.
-            if promoted.is_none() && cx.tcx.trait_of_item(def.did).is_none() {
-                let qualifs = if let Some((did, param_did)) = def.as_const_arg() {
-                    cx.tcx.at(constant.span).mir_const_qualif_const_arg((did, param_did))
-                } else {
-                    cx.tcx.at(constant.span).mir_const_qualif(def.did)
-                };
+    // FIXME(valtrees): check whether const qualifs should behave the same
+    // way for type and mir constants.
+    let uneval = match constant.literal {
+        ConstantKind::Ty(ct) if matches!(ct.kind(), ty::ConstKind::Param(_)) => None,
+        ConstantKind::Ty(c) => bug!("expected ConstKind::Param here, found {:?}", c),
+        ConstantKind::Unevaluated(uv, _) => Some(uv),
+        ConstantKind::Val(..) => None,
+    };
 
-                if !Q::in_qualifs(&qualifs) {
-                    return false;
-                }
+    if let Some(mir::UnevaluatedConst { def, substs: _, promoted }) = uneval {
+        // Use qualifs of the type for the promoted. Promoteds in MIR body should be possible
+        // only for `NeedsNonConstDrop` with precise drop checking. This is the only const
+        // check performed after the promotion. Verify that with an assertion.
+        assert!(promoted.is_none() || Q::ALLOW_PROMOTED);
 
-                // Just in case the type is more specific than
-                // the definition, e.g., impl associated const
-                // with type parameters, take it into account.
+        // Don't peek inside trait associated constants.
+        if promoted.is_none() && cx.tcx.trait_of_item(def.did).is_none() {
+            assert_eq!(def.const_param_did, None, "expected associated const: {def:?}");
+            let qualifs = cx.tcx.at(constant.span).mir_const_qualif(def.did);
+
+            if !Q::in_qualifs(&qualifs) {
+                return false;
             }
+
+            // Just in case the type is more specific than
+            // the definition, e.g., impl associated const
+            // with type parameters, take it into account.
         }
     }
+
     // Otherwise use the qualifs of the type.
     Q::in_any_value_of_ty(cx, constant.literal.ty())
 }
diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs
index f5ba408bee0e..4b219300739c 100644
--- a/compiler/rustc_const_eval/src/transform/promote_consts.rs
+++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs
@@ -13,6 +13,7 @@
 //! move analysis runs after promotion on broken MIR.
 
 use rustc_hir as hir;
+use rustc_middle::mir;
 use rustc_middle::mir::traversal::ReversePostorderIter;
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
@@ -361,7 +362,7 @@ impl<'tcx> Validator<'_, 'tcx> {
                             return Err(Unpromotable);
                         }
                     }
-                    ProjectionElem::Downcast(..) => {
+                    ProjectionElem::OpaqueCast(..) | ProjectionElem::Downcast(..) => {
                         return Err(Unpromotable);
                     }
 
@@ -840,21 +841,15 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                 promoted.span = span;
                 promoted.local_decls[RETURN_PLACE] = LocalDecl::new(ty, span);
                 let substs = tcx.erase_regions(InternalSubsts::identity_for_item(tcx, def.did));
-                let _const = tcx.mk_const(ty::ConstS {
-                    ty,
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                        def,
-                        substs,
-                        promoted: Some(promoted_id),
-                    }),
-                });
+                let uneval = mir::UnevaluatedConst { def, substs, promoted: Some(promoted_id) };
 
                 Operand::Constant(Box::new(Constant {
                     span,
                     user_ty: None,
-                    literal: ConstantKind::from_const(_const, tcx),
+                    literal: ConstantKind::Unevaluated(uneval, ty),
                 }))
             };
+
             let blocks = self.source.basic_blocks.as_mut();
             let local_decls = &mut self.source.local_decls;
             let loc = candidate.location;
diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index b662513e70fb..9c95ffca19bc 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -7,12 +7,12 @@ use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::{
-    traversal, AggregateKind, BasicBlock, BinOp, Body, BorrowKind, CastKind, Local, Location,
-    MirPass, MirPhase, Operand, Place, PlaceElem, PlaceRef, ProjectionElem, RuntimePhase, Rvalue,
-    SourceScope, Statement, StatementKind, Terminator, TerminatorKind, UnOp, START_BLOCK,
+    traversal, AggregateKind, BasicBlock, BinOp, Body, BorrowKind, CastKind, CopyNonOverlapping,
+    Local, Location, MirPass, MirPhase, NonDivergingIntrinsic, Operand, Place, PlaceElem, PlaceRef,
+    ProjectionElem, RuntimePhase, Rvalue, SourceScope, Statement, StatementKind, Terminator,
+    TerminatorKind, UnOp, START_BLOCK,
 };
 use rustc_middle::ty::fold::BottomUpFolder;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeFoldable, TypeVisitable};
 use rustc_mir_dataflow::impls::MaybeStorageLive;
 use rustc_mir_dataflow::storage::always_storage_live_locals;
@@ -89,20 +89,21 @@ pub fn equal_up_to_regions<'tcx>(
 
     // Normalize lifetimes away on both sides, then compare.
     let normalize = |ty: Ty<'tcx>| {
-        let ty = ty.fold_with(&mut BottomUpFolder {
-            tcx,
-            // FIXME: We erase all late-bound lifetimes, but this is not fully correct.
-            // If you have a type like `<for<'a> fn(&'a u32) as SomeTrait>::Assoc`,
-            // this is not necessarily equivalent to `<fn(&'static u32) as SomeTrait>::Assoc`,
-            // since one may have an `impl SomeTrait for fn(&32)` and
-            // `impl SomeTrait for fn(&'static u32)` at the same time which
-            // specify distinct values for Assoc. (See also #56105)
-            lt_op: |_| tcx.lifetimes.re_erased,
-            // Leave consts and types unchanged.
-            ct_op: |ct| ct,
-            ty_op: |ty| ty,
-        });
-        tcx.try_normalize_erasing_regions(param_env, ty).unwrap_or(ty)
+        tcx.try_normalize_erasing_regions(param_env, ty).unwrap_or(ty).fold_with(
+            &mut BottomUpFolder {
+                tcx,
+                // FIXME: We erase all late-bound lifetimes, but this is not fully correct.
+                // If you have a type like `<for<'a> fn(&'a u32) as SomeTrait>::Assoc`,
+                // this is not necessarily equivalent to `<fn(&'static u32) as SomeTrait>::Assoc`,
+                // since one may have an `impl SomeTrait for fn(&32)` and
+                // `impl SomeTrait for fn(&'static u32)` at the same time which
+                // specify distinct values for Assoc. (See also #56105)
+                lt_op: |_| tcx.lifetimes.re_erased,
+                // Leave consts and types unchanged.
+                ct_op: |ct| ct,
+                ty_op: |ty| ty,
+            },
+        )
     };
     tcx.infer_ctxt().enter(|infcx| infcx.can_eq(param_env, normalize(src), normalize(dest)).is_ok())
 }
@@ -181,16 +182,23 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         if (src, dest).has_opaque_types() {
             return true;
         }
-        // Normalize projections and things like that.
-        let param_env = self.param_env.with_reveal_all_normalized(self.tcx);
-        let src = self.tcx.normalize_erasing_regions(param_env, src);
-        let dest = self.tcx.normalize_erasing_regions(param_env, dest);
 
+        // Normalize projections and things like that.
         // Type-changing assignments can happen when subtyping is used. While
         // all normal lifetimes are erased, higher-ranked types with their
         // late-bound lifetimes are still around and can lead to type
         // differences. So we compare ignoring lifetimes.
-        equal_up_to_regions(self.tcx, param_env, src, dest)
+
+        // First, try with reveal_all. This might not work in some cases, as the predicates
+        // can be cleared in reveal_all mode. We try the reveal first anyways as it is used
+        // by some other passes like inlining as well.
+        let param_env = self.param_env.with_reveal_all_normalized(self.tcx);
+        if equal_up_to_regions(self.tcx, param_env, src, dest) {
+            return true;
+        }
+
+        // If this fails, we can try it without the reveal.
+        equal_up_to_regions(self.tcx, self.param_env, src, dest)
     }
 }
 
@@ -560,6 +568,9 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                             );
                         }
                     }
+                    CastKind::DynStar => {
+                        // FIXME(dyn-star): make sure nothing needs to be done here.
+                    }
                     // Nothing to check here
                     CastKind::PointerFromExposedAddress
                     | CastKind::PointerExposeAddress
@@ -629,11 +640,18 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                     );
                 }
             }
-            StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
-                ref src,
-                ref dst,
-                ref count,
-            }) => {
+            StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(op)) => {
+                let ty = op.ty(&self.body.local_decls, self.tcx);
+                if !ty.is_bool() {
+                    self.fail(
+                        location,
+                        format!("`assume` argument must be `bool`, but got: `{}`", ty),
+                    );
+                }
+            }
+            StatementKind::Intrinsic(box NonDivergingIntrinsic::CopyNonOverlapping(
+                CopyNonOverlapping { src, dst, count },
+            )) => {
                 let src_ty = src.ty(&self.body.local_decls, self.tcx);
                 let op_src_ty = if let Some(src_deref) = src_ty.builtin_deref(true) {
                     src_deref.ty
diff --git a/compiler/rustc_data_structures/Cargo.toml b/compiler/rustc_data_structures/Cargo.toml
index 5c641f54f686..2d8658db5e6a 100644
--- a/compiler/rustc_data_structures/Cargo.toml
+++ b/compiler/rustc_data_structures/Cargo.toml
@@ -8,25 +8,26 @@ doctest = false
 
 [dependencies]
 arrayvec = { version = "0.7", default-features = false }
+bitflags = "1.2.1"
+cfg-if = "0.1.2"
 ena = "0.14"
 indexmap = { version = "1.9.1" }
-tracing = "0.1"
 jobserver_crate = { version = "0.1.13", package = "jobserver" }
-rustc_serialize = { path = "../rustc_serialize" }
-rustc_macros = { path = "../rustc_macros" }
-rustc_graphviz = { path = "../rustc_graphviz" }
-cfg-if = "0.1.2"
-stable_deref_trait = "1.0.0"
-rayon = { version = "0.4.0", package = "rustc-rayon", optional = true }
-rayon-core = { version = "0.4.0", package = "rustc-rayon-core", optional = true }
-rustc-hash = "1.1.0"
-smallvec = { version = "1.8.1", features = ["const_generics", "union", "may_dangle"] }
-rustc_index = { path = "../rustc_index", package = "rustc_index" }
-bitflags = "1.2.1"
-measureme = "10.0.0"
 libc = "0.2"
+measureme = "10.0.0"
+rayon-core = { version = "0.4.0", package = "rustc-rayon-core", optional = true }
+rayon = { version = "0.4.0", package = "rustc-rayon", optional = true }
+rustc_graphviz = { path = "../rustc_graphviz" }
+rustc-hash = "1.1.0"
+rustc_index = { path = "../rustc_index", package = "rustc_index" }
+rustc_macros = { path = "../rustc_macros" }
+rustc_serialize = { path = "../rustc_serialize" }
+smallvec = { version = "1.8.1", features = ["const_generics", "union", "may_dangle"] }
+stable_deref_trait = "1.0.0"
 stacker = "0.1.14"
 tempfile = "3.2"
+thin-vec = "0.2.8"
+tracing = "0.1"
 
 [dependencies.parking_lot]
 version = "0.11"
diff --git a/compiler/rustc_data_structures/src/fingerprint.rs b/compiler/rustc_data_structures/src/fingerprint.rs
index 5ff2d18dd2be..a39178016ce2 100644
--- a/compiler/rustc_data_structures/src/fingerprint.rs
+++ b/compiler/rustc_data_structures/src/fingerprint.rs
@@ -29,7 +29,7 @@ impl Fingerprint {
         // quality hash values, let's still combine the two values because the
         // Fingerprints in DefPathHash have the StableCrateId portion which is
         // the same for all DefPathHashes from the same crate. Combining the
-        // two halfs makes sure we get a good quality hash in such cases too.
+        // two halves makes sure we get a good quality hash in such cases too.
         self.0.wrapping_mul(3).wrapping_add(self.1)
     }
 
@@ -120,7 +120,7 @@ impl FingerprintHasher for crate::unhash::Unhasher {
         // quality hash values, let's still combine the two values because the
         // Fingerprints in DefPathHash have the StableCrateId portion which is
         // the same for all DefPathHashes from the same crate. Combining the
-        // two halfs makes sure we get a good quality hash in such cases too.
+        // two halves makes sure we get a good quality hash in such cases too.
         //
         // Since `Unhasher` is used only in the context of HashMaps, it is OK
         // to combine the two components in an order-independent way (which is
diff --git a/compiler/rustc_data_structures/src/fx.rs b/compiler/rustc_data_structures/src/fx.rs
index bbeb193dba32..0d0c51b68194 100644
--- a/compiler/rustc_data_structures/src/fx.rs
+++ b/compiler/rustc_data_structures/src/fx.rs
@@ -2,13 +2,26 @@ use std::hash::BuildHasherDefault;
 
 pub use rustc_hash::{FxHashMap, FxHashSet, FxHasher};
 
+pub type StdEntry<'a, K, V> = std::collections::hash_map::Entry<'a, K, V>;
+
 pub type FxIndexMap<K, V> = indexmap::IndexMap<K, V, BuildHasherDefault<FxHasher>>;
 pub type FxIndexSet<V> = indexmap::IndexSet<V, BuildHasherDefault<FxHasher>>;
+pub type IndexEntry<'a, K, V> = indexmap::map::Entry<'a, K, V>;
 
 #[macro_export]
 macro_rules! define_id_collections {
-    ($map_name:ident, $set_name:ident, $key:ty) => {
+    ($map_name:ident, $set_name:ident, $entry_name:ident, $key:ty) => {
         pub type $map_name<T> = $crate::fx::FxHashMap<$key, T>;
         pub type $set_name = $crate::fx::FxHashSet<$key>;
+        pub type $entry_name<'a, T> = $crate::fx::StdEntry<'a, $key, T>;
+    };
+}
+
+#[macro_export]
+macro_rules! define_stable_id_collections {
+    ($map_name:ident, $set_name:ident, $entry_name:ident, $key:ty) => {
+        pub type $map_name<T> = $crate::fx::FxIndexMap<$key, T>;
+        pub type $set_name = $crate::fx::FxIndexSet<$key>;
+        pub type $entry_name<'a, T> = $crate::fx::IndexEntry<'a, $key, T>;
     };
 }
diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index c8b09cffe013..467ac401d086 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -13,7 +13,6 @@
 #![feature(cell_leak)]
 #![feature(control_flow_enum)]
 #![feature(extend_one)]
-#![feature(let_else)]
 #![feature(hash_raw_entry)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(maybe_uninit_uninit_array)]
@@ -75,7 +74,6 @@ pub mod profiling;
 pub mod sharded;
 pub mod stack;
 pub mod sync;
-pub mod thin_vec;
 pub mod tiny_list;
 pub mod transitive_relation;
 pub mod vec_linked_list;
diff --git a/compiler/rustc_data_structures/src/map_in_place.rs b/compiler/rustc_data_structures/src/map_in_place.rs
index d912211443a8..a0d4b7ade1f3 100644
--- a/compiler/rustc_data_structures/src/map_in_place.rs
+++ b/compiler/rustc_data_structures/src/map_in_place.rs
@@ -1,6 +1,6 @@
-use crate::thin_vec::ThinVec;
 use smallvec::{Array, SmallVec};
 use std::ptr;
+use thin_vec::ThinVec;
 
 pub trait MapInPlace<T>: Sized {
     fn map_in_place<F>(&mut self, mut f: F)
diff --git a/compiler/rustc_data_structures/src/obligation_forest/mod.rs b/compiler/rustc_data_structures/src/obligation_forest/mod.rs
index 07a96dd7dbbf..10e673cd9297 100644
--- a/compiler/rustc_data_structures/src/obligation_forest/mod.rs
+++ b/compiler/rustc_data_structures/src/obligation_forest/mod.rs
@@ -95,6 +95,10 @@ pub trait ForestObligation: Clone + Debug {
 pub trait ObligationProcessor {
     type Obligation: ForestObligation;
     type Error: Debug;
+    type OUT: OutcomeTrait<
+        Obligation = Self::Obligation,
+        Error = Error<Self::Obligation, Self::Error>,
+    >;
 
     fn needs_process_obligation(&self, obligation: &Self::Obligation) -> bool;
 
@@ -111,12 +115,20 @@ pub trait ObligationProcessor {
     /// In other words, if we had O1 which required O2 which required
     /// O3 which required O1, we would give an iterator yielding O1,
     /// O2, O3 (O1 is not yielded twice).
-    fn process_backedge<'c, I>(&mut self, cycle: I, _marker: PhantomData<&'c Self::Obligation>)
+    fn process_backedge<'c, I>(
+        &mut self,
+        cycle: I,
+        _marker: PhantomData<&'c Self::Obligation>,
+    ) -> Result<(), Self::Error>
     where
         I: Clone + Iterator<Item = &'c Self::Obligation>;
 }
 
 /// The result type used by `process_obligation`.
+// `repr(C)` to inhibit the niche filling optimization. Otherwise, the `match` appearing
+// in `process_obligations` is significantly slower, which can substantially affect
+// benchmarks like `rustc-perf`'s inflate and keccak.
+#[repr(C)]
 #[derive(Debug)]
 pub enum ProcessResult<O, E> {
     Unchanged,
@@ -398,12 +410,11 @@ impl<O: ForestObligation> ObligationForest<O> {
 
     /// Performs a fixpoint computation over the obligation list.
     #[inline(never)]
-    pub fn process_obligations<P, OUT>(&mut self, processor: &mut P) -> OUT
+    pub fn process_obligations<P>(&mut self, processor: &mut P) -> P::OUT
     where
         P: ObligationProcessor<Obligation = O>,
-        OUT: OutcomeTrait<Obligation = O, Error = Error<O, P::Error>>,
     {
-        let mut outcome = OUT::new();
+        let mut outcome = P::OUT::new();
 
         // Fixpoint computation: we repeat until the inner loop stalls.
         loop {
@@ -469,7 +480,7 @@ impl<O: ForestObligation> ObligationForest<O> {
             }
 
             self.mark_successes();
-            self.process_cycles(processor);
+            self.process_cycles(processor, &mut outcome);
             self.compress(|obl| outcome.record_completed(obl));
         }
 
@@ -554,7 +565,7 @@ impl<O: ForestObligation> ObligationForest<O> {
 
     /// Report cycles between all `Success` nodes, and convert all `Success`
     /// nodes to `Done`. This must be called after `mark_successes`.
-    fn process_cycles<P>(&mut self, processor: &mut P)
+    fn process_cycles<P>(&mut self, processor: &mut P, outcome: &mut P::OUT)
     where
         P: ObligationProcessor<Obligation = O>,
     {
@@ -564,7 +575,7 @@ impl<O: ForestObligation> ObligationForest<O> {
             // to handle the no-op cases immediately to avoid the cost of the
             // function call.
             if node.state.get() == NodeState::Success {
-                self.find_cycles_from_node(&mut stack, processor, index);
+                self.find_cycles_from_node(&mut stack, processor, index, outcome);
             }
         }
 
@@ -572,8 +583,13 @@ impl<O: ForestObligation> ObligationForest<O> {
         self.reused_node_vec = stack;
     }
 
-    fn find_cycles_from_node<P>(&self, stack: &mut Vec<usize>, processor: &mut P, index: usize)
-    where
+    fn find_cycles_from_node<P>(
+        &self,
+        stack: &mut Vec<usize>,
+        processor: &mut P,
+        index: usize,
+        outcome: &mut P::OUT,
+    ) where
         P: ObligationProcessor<Obligation = O>,
     {
         let node = &self.nodes[index];
@@ -582,17 +598,20 @@ impl<O: ForestObligation> ObligationForest<O> {
                 None => {
                     stack.push(index);
                     for &dep_index in node.dependents.iter() {
-                        self.find_cycles_from_node(stack, processor, dep_index);
+                        self.find_cycles_from_node(stack, processor, dep_index, outcome);
                     }
                     stack.pop();
                     node.state.set(NodeState::Done);
                 }
                 Some(rpos) => {
                     // Cycle detected.
-                    processor.process_backedge(
+                    let result = processor.process_backedge(
                         stack[rpos..].iter().map(|&i| &self.nodes[i].obligation),
                         PhantomData,
                     );
+                    if let Err(err) = result {
+                        outcome.record_error(Error { error: err, backtrace: self.error_at(index) });
+                    }
                 }
             }
         }
diff --git a/compiler/rustc_data_structures/src/obligation_forest/tests.rs b/compiler/rustc_data_structures/src/obligation_forest/tests.rs
index e2991aae1742..bc252f772a16 100644
--- a/compiler/rustc_data_structures/src/obligation_forest/tests.rs
+++ b/compiler/rustc_data_structures/src/obligation_forest/tests.rs
@@ -64,6 +64,7 @@ where
 {
     type Obligation = O;
     type Error = E;
+    type OUT = TestOutcome<O, E>;
 
     fn needs_process_obligation(&self, _obligation: &Self::Obligation) -> bool {
         true
@@ -76,10 +77,15 @@ where
         (self.process_obligation)(obligation)
     }
 
-    fn process_backedge<'c, I>(&mut self, _cycle: I, _marker: PhantomData<&'c Self::Obligation>)
+    fn process_backedge<'c, I>(
+        &mut self,
+        _cycle: I,
+        _marker: PhantomData<&'c Self::Obligation>,
+    ) -> Result<(), Self::Error>
     where
         I: Clone + Iterator<Item = &'c Self::Obligation>,
     {
+        Ok(())
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/sorted_map.rs b/compiler/rustc_data_structures/src/sorted_map.rs
index 9efea1228ab2..937cb671573a 100644
--- a/compiler/rustc_data_structures/src/sorted_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map.rs
@@ -164,7 +164,7 @@ impl<K: Ord, V> SortedMap<K, V> {
     /// It is up to the caller to make sure that the elements are sorted by key
     /// and that there are no duplicates.
     #[inline]
-    pub fn insert_presorted(&mut self, mut elements: Vec<(K, V)>) {
+    pub fn insert_presorted(&mut self, elements: Vec<(K, V)>) {
         if elements.is_empty() {
             return;
         }
@@ -173,28 +173,28 @@ impl<K: Ord, V> SortedMap<K, V> {
 
         let start_index = self.lookup_index_for(&elements[0].0);
 
-        let drain = match start_index {
+        let elements = match start_index {
             Ok(index) => {
-                let mut drain = elements.drain(..);
-                self.data[index] = drain.next().unwrap();
-                drain
+                let mut elements = elements.into_iter();
+                self.data[index] = elements.next().unwrap();
+                elements
             }
             Err(index) => {
                 if index == self.data.len() || elements.last().unwrap().0 < self.data[index].0 {
                     // We can copy the whole range without having to mix with
                     // existing elements.
-                    self.data.splice(index..index, elements.drain(..));
+                    self.data.splice(index..index, elements.into_iter());
                     return;
                 }
 
-                let mut drain = elements.drain(..);
-                self.data.insert(index, drain.next().unwrap());
-                drain
+                let mut elements = elements.into_iter();
+                self.data.insert(index, elements.next().unwrap());
+                elements
             }
         };
 
         // Insert the rest
-        for (k, v) in drain {
+        for (k, v) in elements {
             self.insert(k, v);
         }
     }
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 258780ecaea2..9c0fb8265cff 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -48,7 +48,7 @@ cfg_if! {
         /// the native atomic types.
         /// You should use this type through the `AtomicU64`, `AtomicUsize`, etc, type aliases
         /// as it's not intended to be used separately.
-        #[derive(Debug)]
+        #[derive(Debug, Default)]
         pub struct Atomic<T: Copy>(Cell<T>);
 
         impl<T: Copy> Atomic<T> {
diff --git a/compiler/rustc_data_structures/src/thin_vec.rs b/compiler/rustc_data_structures/src/thin_vec.rs
deleted file mode 100644
index fce42e709ab7..000000000000
--- a/compiler/rustc_data_structures/src/thin_vec.rs
+++ /dev/null
@@ -1,180 +0,0 @@
-use crate::stable_hasher::{HashStable, StableHasher};
-
-use std::iter::FromIterator;
-
-/// A vector type optimized for cases where this size is usually 0 (cf. `SmallVec`).
-/// The `Option<Box<..>>` wrapping allows us to represent a zero sized vector with `None`,
-/// which uses only a single (null) pointer.
-#[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq)]
-pub struct ThinVec<T>(Option<Box<Vec<T>>>);
-
-impl<T> ThinVec<T> {
-    pub fn new() -> Self {
-        ThinVec(None)
-    }
-
-    pub fn iter(&self) -> std::slice::Iter<'_, T> {
-        self.into_iter()
-    }
-
-    pub fn iter_mut(&mut self) -> std::slice::IterMut<'_, T> {
-        self.into_iter()
-    }
-
-    pub fn push(&mut self, item: T) {
-        match *self {
-            ThinVec(Some(ref mut vec)) => vec.push(item),
-            ThinVec(None) => *self = vec![item].into(),
-        }
-    }
-
-    /// Note: if `set_len(0)` is called on a non-empty `ThinVec`, it will
-    /// remain in the `Some` form. This is required for some code sequences
-    /// (such as the one in `flat_map_in_place`) that call `set_len(0)` before
-    /// an operation that might panic, and then call `set_len(n)` again
-    /// afterwards.
-    pub unsafe fn set_len(&mut self, new_len: usize) {
-        match *self {
-            ThinVec(None) => {
-                // A prerequisite of `Vec::set_len` is that `new_len` must be
-                // less than or equal to capacity(). The same applies here.
-                if new_len != 0 {
-                    panic!("unsafe ThinVec::set_len({})", new_len);
-                }
-            }
-            ThinVec(Some(ref mut vec)) => vec.set_len(new_len),
-        }
-    }
-
-    pub fn insert(&mut self, index: usize, value: T) {
-        match *self {
-            ThinVec(None) => {
-                if index == 0 {
-                    *self = vec![value].into();
-                } else {
-                    panic!("invalid ThinVec::insert");
-                }
-            }
-            ThinVec(Some(ref mut vec)) => vec.insert(index, value),
-        }
-    }
-
-    pub fn remove(&mut self, index: usize) -> T {
-        match self {
-            ThinVec(None) => panic!("invalid ThinVec::remove"),
-            ThinVec(Some(vec)) => vec.remove(index),
-        }
-    }
-
-    pub fn as_slice(&self) -> &[T] {
-        match self {
-            ThinVec(None) => &[],
-            ThinVec(Some(vec)) => vec.as_slice(),
-        }
-    }
-}
-
-impl<T> From<Vec<T>> for ThinVec<T> {
-    fn from(vec: Vec<T>) -> Self {
-        if vec.is_empty() { ThinVec(None) } else { ThinVec(Some(Box::new(vec))) }
-    }
-}
-
-impl<T> Into<Vec<T>> for ThinVec<T> {
-    fn into(self) -> Vec<T> {
-        match self {
-            ThinVec(None) => Vec::new(),
-            ThinVec(Some(vec)) => *vec,
-        }
-    }
-}
-
-impl<T> ::std::ops::Deref for ThinVec<T> {
-    type Target = [T];
-    fn deref(&self) -> &[T] {
-        match *self {
-            ThinVec(None) => &[],
-            ThinVec(Some(ref vec)) => vec,
-        }
-    }
-}
-
-impl<T> ::std::ops::DerefMut for ThinVec<T> {
-    fn deref_mut(&mut self) -> &mut [T] {
-        match *self {
-            ThinVec(None) => &mut [],
-            ThinVec(Some(ref mut vec)) => vec,
-        }
-    }
-}
-
-impl<T> FromIterator<T> for ThinVec<T> {
-    fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
-        // `Vec::from_iter()` should not allocate if the iterator is empty.
-        let vec: Vec<_> = iter.into_iter().collect();
-        if vec.is_empty() { ThinVec(None) } else { ThinVec(Some(Box::new(vec))) }
-    }
-}
-
-impl<T> IntoIterator for ThinVec<T> {
-    type Item = T;
-    type IntoIter = std::vec::IntoIter<T>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        // This is still performant because `Vec::new()` does not allocate.
-        self.0.map_or_else(Vec::new, |ptr| *ptr).into_iter()
-    }
-}
-
-impl<'a, T> IntoIterator for &'a ThinVec<T> {
-    type Item = &'a T;
-    type IntoIter = std::slice::Iter<'a, T>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.as_ref().iter()
-    }
-}
-
-impl<'a, T> IntoIterator for &'a mut ThinVec<T> {
-    type Item = &'a mut T;
-    type IntoIter = std::slice::IterMut<'a, T>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.as_mut().iter_mut()
-    }
-}
-
-impl<T> Extend<T> for ThinVec<T> {
-    fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
-        match *self {
-            ThinVec(Some(ref mut vec)) => vec.extend(iter),
-            ThinVec(None) => *self = iter.into_iter().collect::<Vec<_>>().into(),
-        }
-    }
-
-    fn extend_one(&mut self, item: T) {
-        self.push(item)
-    }
-
-    fn extend_reserve(&mut self, additional: usize) {
-        match *self {
-            ThinVec(Some(ref mut vec)) => vec.reserve(additional),
-            ThinVec(None) => *self = Vec::with_capacity(additional).into(),
-        }
-    }
-}
-
-impl<T: HashStable<CTX>, CTX> HashStable<CTX> for ThinVec<T> {
-    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        (**self).hash_stable(hcx, hasher)
-    }
-}
-
-impl<T> Default for ThinVec<T> {
-    fn default() -> Self {
-        Self(None)
-    }
-}
-
-#[cfg(test)]
-mod tests;
diff --git a/compiler/rustc_data_structures/src/thin_vec/tests.rs b/compiler/rustc_data_structures/src/thin_vec/tests.rs
deleted file mode 100644
index 0221b9912bbd..000000000000
--- a/compiler/rustc_data_structures/src/thin_vec/tests.rs
+++ /dev/null
@@ -1,42 +0,0 @@
-use super::*;
-
-impl<T> ThinVec<T> {
-    fn into_vec(self) -> Vec<T> {
-        self.into()
-    }
-}
-
-#[test]
-fn test_from_iterator() {
-    assert_eq!(std::iter::empty().collect::<ThinVec<String>>().into_vec(), Vec::<String>::new());
-    assert_eq!(std::iter::once(42).collect::<ThinVec<_>>().into_vec(), vec![42]);
-    assert_eq!([1, 2].into_iter().collect::<ThinVec<_>>().into_vec(), vec![1, 2]);
-    assert_eq!([1, 2, 3].into_iter().collect::<ThinVec<_>>().into_vec(), vec![1, 2, 3]);
-}
-
-#[test]
-fn test_into_iterator_owned() {
-    assert_eq!(ThinVec::new().into_iter().collect::<Vec<String>>(), Vec::<String>::new());
-    assert_eq!(ThinVec::from(vec![1]).into_iter().collect::<Vec<_>>(), vec![1]);
-    assert_eq!(ThinVec::from(vec![1, 2]).into_iter().collect::<Vec<_>>(), vec![1, 2]);
-    assert_eq!(ThinVec::from(vec![1, 2, 3]).into_iter().collect::<Vec<_>>(), vec![1, 2, 3]);
-}
-
-#[test]
-fn test_into_iterator_ref() {
-    assert_eq!(ThinVec::new().iter().collect::<Vec<&String>>(), Vec::<&String>::new());
-    assert_eq!(ThinVec::from(vec![1]).iter().collect::<Vec<_>>(), vec![&1]);
-    assert_eq!(ThinVec::from(vec![1, 2]).iter().collect::<Vec<_>>(), vec![&1, &2]);
-    assert_eq!(ThinVec::from(vec![1, 2, 3]).iter().collect::<Vec<_>>(), vec![&1, &2, &3]);
-}
-
-#[test]
-fn test_into_iterator_ref_mut() {
-    assert_eq!(ThinVec::new().iter_mut().collect::<Vec<&mut String>>(), Vec::<&mut String>::new());
-    assert_eq!(ThinVec::from(vec![1]).iter_mut().collect::<Vec<_>>(), vec![&mut 1]);
-    assert_eq!(ThinVec::from(vec![1, 2]).iter_mut().collect::<Vec<_>>(), vec![&mut 1, &mut 2]);
-    assert_eq!(
-        ThinVec::from(vec![1, 2, 3]).iter_mut().collect::<Vec<_>>(),
-        vec![&mut 1, &mut 2, &mut 3],
-    );
-}
diff --git a/compiler/rustc_driver/Cargo.toml b/compiler/rustc_driver/Cargo.toml
index 4570c1448337..d1d02ed73f95 100644
--- a/compiler/rustc_driver/Cargo.toml
+++ b/compiler/rustc_driver/Cargo.toml
@@ -7,7 +7,7 @@ edition = "2021"
 crate-type = ["dylib"]
 
 [dependencies]
-tracing = { version = "0.1.28" }
+tracing = { version = "0.1.35" }
 serde_json = "1.0.59"
 rustc_log = { path = "../rustc_log" }
 rustc_middle = { path = "../rustc_middle" }
diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index a193d5db6916..fcd49f5d0156 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -5,7 +5,6 @@
 //! This API is completely unstable and subject to change.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(let_else)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
@@ -742,6 +741,11 @@ fn print_crate_info(
                     println!("{}", cfg);
                 }
             }
+            CallingConventions => {
+                let mut calling_conventions = rustc_target::spec::abi::all_names();
+                calling_conventions.sort_unstable();
+                println!("{}", calling_conventions.join("\n"));
+            }
             RelocationModels
             | CodeModels
             | TlsModels
@@ -1119,22 +1123,25 @@ fn extra_compiler_flags() -> Option<(Vec<String>, bool)> {
     while let Some(arg) = args.next() {
         if let Some(a) = ICE_REPORT_COMPILER_FLAGS.iter().find(|a| arg.starts_with(*a)) {
             let content = if arg.len() == a.len() {
+                // A space-separated option, like `-C incremental=foo` or `--crate-type rlib`
                 match args.next() {
                     Some(arg) => arg.to_string(),
                     None => continue,
                 }
             } else if arg.get(a.len()..a.len() + 1) == Some("=") {
+                // An equals option, like `--crate-type=rlib`
                 arg[a.len() + 1..].to_string()
             } else {
+                // A non-space option, like `-Cincremental=foo`
                 arg[a.len()..].to_string()
             };
-            if ICE_REPORT_COMPILER_FLAGS_EXCLUDE.iter().any(|exc| content.starts_with(exc)) {
+            let option = content.split_once('=').map(|s| s.0).unwrap_or(&content);
+            if ICE_REPORT_COMPILER_FLAGS_EXCLUDE.iter().any(|exc| option == *exc) {
                 excluded_cargo_defaults = true;
             } else {
                 result.push(a.to_string());
-                match ICE_REPORT_COMPILER_FLAGS_STRIP_VALUE.iter().find(|s| content.starts_with(*s))
-                {
-                    Some(s) => result.push(s.to_string()),
+                match ICE_REPORT_COMPILER_FLAGS_STRIP_VALUE.iter().find(|s| option == **s) {
+                    Some(s) => result.push(format!("{}=[REDACTED]", s)),
                     None => result.push(content),
                 }
             }
diff --git a/compiler/rustc_driver/src/pretty.rs b/compiler/rustc_driver/src/pretty.rs
index f66b1a2976f1..e97da4322fa0 100644
--- a/compiler/rustc_driver/src/pretty.rs
+++ b/compiler/rustc_driver/src/pretty.rs
@@ -1,5 +1,6 @@
 //! The various pretty-printing routines.
 
+use crate::session_diagnostics::UnprettyDumpFail;
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust;
 use rustc_errors::ErrorGuaranteed;
@@ -328,7 +329,7 @@ impl<'tcx> pprust_hir::PpAnn for TypedAnnotation<'tcx> {
             let typeck_results = self.maybe_typeck_results.get().or_else(|| {
                 self.tcx
                     .hir()
-                    .maybe_body_owned_by(expr.hir_id.owner)
+                    .maybe_body_owned_by(expr.hir_id.owner.def_id)
                     .map(|body_id| self.tcx.typeck_body(body_id))
             });
 
@@ -357,12 +358,15 @@ fn get_source(input: &Input, sess: &Session) -> (String, FileName) {
     (src, src_name)
 }
 
-fn write_or_print(out: &str, ofile: Option<&Path>) {
+fn write_or_print(out: &str, ofile: Option<&Path>, sess: &Session) {
     match ofile {
         None => print!("{}", out),
         Some(p) => {
             if let Err(e) = std::fs::write(p, out) {
-                panic!("print-print failed to write {} due to {}", p.display(), e);
+                sess.emit_fatal(UnprettyDumpFail {
+                    path: p.display().to_string(),
+                    err: e.to_string(),
+                });
             }
         }
     }
@@ -392,6 +396,7 @@ pub fn print_after_parsing(
                     annotation.pp_ann(),
                     false,
                     parse.edition,
+                    &sess.parse_sess.attr_id_generator,
                 )
             })
         }
@@ -402,7 +407,7 @@ pub fn print_after_parsing(
         _ => unreachable!(),
     };
 
-    write_or_print(&out, ofile);
+    write_or_print(&out, ofile, sess);
 }
 
 pub fn print_after_hir_lowering<'tcx>(
@@ -434,6 +439,7 @@ pub fn print_after_hir_lowering<'tcx>(
                     annotation.pp_ann(),
                     true,
                     parse.edition,
+                    &sess.parse_sess.attr_id_generator,
                 )
             })
         }
@@ -468,7 +474,7 @@ pub fn print_after_hir_lowering<'tcx>(
         _ => unreachable!(),
     };
 
-    write_or_print(&out, ofile);
+    write_or_print(&out, ofile, tcx.sess);
 }
 
 // In an ideal world, this would be a public function called by the driver after
@@ -512,7 +518,7 @@ fn print_with_analysis(
         _ => unreachable!(),
     };
 
-    write_or_print(&out, ofile);
+    write_or_print(&out, ofile, tcx.sess);
 
     Ok(())
 }
diff --git a/compiler/rustc_driver/src/session_diagnostics.rs b/compiler/rustc_driver/src/session_diagnostics.rs
index fe64d0fca9b2..289baf177737 100644
--- a/compiler/rustc_driver/src/session_diagnostics.rs
+++ b/compiler/rustc_driver/src/session_diagnostics.rs
@@ -1,33 +1,40 @@
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(driver::rlink_unable_to_read)]
 pub(crate) struct RlinkUnableToRead {
     pub err: std::io::Error,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(driver::rlink_wrong_file_type)]
 pub(crate) struct RLinkWrongFileType;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(driver::rlink_empty_version_number)]
 pub(crate) struct RLinkEmptyVersionNumber;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(driver::rlink_encoding_version_mismatch)]
 pub(crate) struct RLinkEncodingVersionMismatch {
     pub version_array: String,
     pub rlink_version: u32,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(driver::rlink_rustc_version_mismatch)]
 pub(crate) struct RLinkRustcVersionMismatch<'a> {
     pub rustc_version: String,
     pub current_version: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(driver::rlink_no_a_file)]
 pub(crate) struct RlinkNotAFile;
+
+#[derive(Diagnostic)]
+#[diag(driver::unpretty_dump_fail)]
+pub(crate) struct UnprettyDumpFail {
+    pub path: String,
+    pub err: String,
+}
diff --git a/compiler/rustc_error_messages/locales/en-US/ast_lowering.ftl b/compiler/rustc_error_messages/locales/en-US/ast_lowering.ftl
index f2790531aba4..03c88c6c0ebe 100644
--- a/compiler/rustc_error_messages/locales/en-US/ast_lowering.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/ast_lowering.ftl
@@ -7,7 +7,9 @@ ast_lowering_use_angle_brackets = use angle brackets instead
 ast_lowering_invalid_abi =
     invalid ABI: found `{$abi}`
     .label = invalid ABI
-    .help = valid ABIs: {$valid_abis}
+    .note = invoke `{$command}` for a full list of supported calling conventions.
+
+ast_lowering_invalid_abi_suggestion = did you mean
 
 ast_lowering_assoc_ty_parentheses =
     parenthesized generic arguments cannot be used in associated type constraints
@@ -131,3 +133,9 @@ ast_lowering_arbitrary_expression_in_pattern =
     arbitrary expressions aren't allowed in patterns
 
 ast_lowering_inclusive_range_with_no_end = inclusive range with no end
+
+ast_lowering_trait_fn_async =
+    functions in traits cannot be declared `async`
+    .label = `async` because of this
+    .note = `async` trait functions are not currently supported
+    .note2 = consider using the `async-trait` crate: https://crates.io/crates/async-trait
diff --git a/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl b/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
index d7108e1e2de3..e5cd1142b20c 100644
--- a/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
@@ -26,12 +26,6 @@ ast_passes_invalid_visibility =
     .individual_impl_items = place qualifiers on individual impl items instead
     .individual_foreign_items = place qualifiers on individual foreign items instead
 
-ast_passes_trait_fn_async =
-    functions in traits cannot be declared `async`
-    .label = `async` because of this
-    .note = `async` trait functions are not currently supported
-    .note2 = consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 ast_passes_trait_fn_const =
     functions in traits cannot be declared const
     .label = functions in traits cannot be const
diff --git a/compiler/rustc_error_messages/locales/en-US/driver.ftl b/compiler/rustc_error_messages/locales/en-US/driver.ftl
index 73f084cf3290..8ad198c86c93 100644
--- a/compiler/rustc_error_messages/locales/en-US/driver.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/driver.ftl
@@ -9,3 +9,5 @@ driver_rlink_encoding_version_mismatch = .rlink file was produced with encoding
 driver_rlink_rustc_version_mismatch = .rlink file was produced by rustc version `{$rustc_version}`, but the current version is `{$current_version}`
 
 driver_rlink_no_a_file = rlink must be a file
+
+driver_unpretty_dump_fail = pretty-print failed to write `{$path}` due to error `{$err}`
diff --git a/compiler/rustc_error_messages/locales/en-US/infer.ftl b/compiler/rustc_error_messages/locales/en-US/infer.ftl
index 60086cd6e477..65371a285911 100644
--- a/compiler/rustc_error_messages/locales/en-US/infer.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/infer.ftl
@@ -104,9 +104,68 @@ infer_relate_object_bound = ...so that it can be closed over into an object
 infer_data_borrowed = ...so that the type `{$name}` is not borrowed for too long
 infer_reference_outlives_referent = ...so that the reference type `{$name}` does not outlive the data it points at
 infer_relate_param_bound = ...so that the type `{$name}` will meet its required lifetime bounds{$continues ->
-[true] ...
-*[false] {""}
+    [true] ...
+    *[false] {""}
 }
 infer_relate_param_bound_2 = ...that is required by this bound
 infer_relate_region_param_bound = ...so that the declared lifetime parameter bounds are satisfied
 infer_compare_impl_item_obligation = ...so that the definition in impl matches the definition from the trait
+infer_ascribe_user_type_prove_predicate = ...so that the where clause holds
+
+infer_nothing = {""}
+
+infer_lifetime_mismatch = lifetime mismatch
+
+infer_declared_different = this parameter and the return type are declared with different lifetimes...
+infer_data_returned = ...but data{$label_var1_exists ->
+    [true] {" "}from `{$label_var1}`
+    *[false] {""}
+} is returned here
+
+infer_data_lifetime_flow = ...but data with one lifetime flows into the other here
+infer_declared_multiple = this type is declared with multiple lifetimes...
+infer_types_declared_different = these two types are declared with different lifetimes...
+infer_data_flows = ...but data{$label_var1_exists ->
+    [true] -> {" "}from `{$label_var1}`
+    *[false] -> {""}
+} flows{$label_var2_exists ->
+    [true] -> {" "}into `{$label_var2}`
+    *[false] -> {""}
+} here
+
+infer_lifetime_param_suggestion = consider introducing a named lifetime parameter{$is_impl ->
+    [true] {" "}and update trait if needed
+    *[false] {""}
+}
+infer_lifetime_param_suggestion_elided = each elided lifetime in input position becomes a distinct lifetime
+
+infer_region_explanation = {$pref_kind ->
+    *[should_not_happen] [{$pref_kind}]
+    [empty] {""}
+}{$pref_kind ->
+    [empty] {""}
+    *[other] {" "}
+}{$desc_kind ->
+    *[should_not_happen] [{$desc_kind}]
+    [restatic] the static lifetime
+    [reempty] the empty lifetime
+    [reemptyuni] the empty lifetime in universe {$desc_arg}
+    [revar] lifetime {$desc_arg}
+
+    [as_defined] the lifetime `{$desc_arg}` as defined here
+    [as_defined_anon] the anonymous lifetime as defined here
+    [defined_here] the anonymous lifetime defined here
+    [anon_num_here] the anonymous lifetime #{$desc_num_arg} defined here
+    [defined_here_reg] the lifetime `{$desc_arg}` as defined here
+}{$suff_kind ->
+    *[should_not_happen] [{$suff_kind}]
+    [empty]{""}
+    [continues] ...
+}
+
+infer_mismatched_static_lifetime = incompatible lifetime on type
+infer_msl_impl_note = ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
+infer_msl_introduces_static = introduces a `'static` lifetime requirement
+infer_msl_unmet_req = because this has an unmet lifetime requirement
+infer_msl_trait_note = this has an implicit `'static` lifetime requirement
+infer_msl_trait_sugg = consider relaxing the implicit `'static` requirement
diff --git a/compiler/rustc_error_messages/locales/en-US/lint.ftl b/compiler/rustc_error_messages/locales/en-US/lint.ftl
index 27ad3e453660..80b0b1a8904a 100644
--- a/compiler/rustc_error_messages/locales/en-US/lint.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/lint.ftl
@@ -51,7 +51,7 @@ lint_non_existant_doc_keyword = found non-existing keyword `{$keyword}` used in
     .help = only existing keywords are allowed in core/std
 
 lint_diag_out_of_impl =
-    diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls
+    diagnostics should only be created in `IntoDiagnostic`/`AddToDiagnostic` impls
 
 lint_untranslatable_diag = diagnostics should be created using translatable messages
 
@@ -354,6 +354,12 @@ lint_builtin_unreachable_pub = unreachable `pub` {$what}
     .suggestion = consider restricting its visibility
     .help = or consider exporting it for use by other crates
 
+lint_builtin_unexpected_cli_config_name = unexpected `{$name}` as condition name
+    .help = was set with `--cfg` but isn't in the `--check-cfg` expected names
+
+lint_builtin_unexpected_cli_config_value = unexpected condition value `{$value}` for condition name `{$name}`
+    .help = was set with `--cfg` but isn't in the `--check-cfg` expected values
+
 lint_builtin_type_alias_bounds_help = use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to associated types in type aliases
 
 lint_builtin_type_alias_where_clause = where clauses are not enforced in type aliases
diff --git a/compiler/rustc_error_messages/locales/en-US/metadata.ftl b/compiler/rustc_error_messages/locales/en-US/metadata.ftl
new file mode 100644
index 000000000000..d27100c56aff
--- /dev/null
+++ b/compiler/rustc_error_messages/locales/en-US/metadata.ftl
@@ -0,0 +1,275 @@
+metadata_rlib_required =
+    crate `{$crate_name}` required to be available in rlib format, but was not found in this form
+
+metadata_lib_required =
+    crate `{$crate_name}` required to be available in {$kind} format, but was not found in this form
+
+metadata_crate_dep_multiple =
+    cannot satisfy dependencies so `{$crate_name}` only shows up once
+    .help = having upstream crates all available in one format will likely make this go away
+
+metadata_two_panic_runtimes =
+    cannot link together two panic runtimes: {$prev_name} and {$cur_name}
+
+metadata_bad_panic_strategy =
+    the linked panic runtime `{$runtime}` is not compiled with this crate's panic strategy `{$strategy}`
+
+metadata_required_panic_strategy =
+    the crate `{$crate_name}` requires panic strategy `{$found_strategy}` which is incompatible with this crate's strategy of `{$desired_strategy}`
+
+metadata_incompatible_panic_in_drop_strategy =
+    the crate `{$crate_name}` is compiled with the panic-in-drop strategy `{$found_strategy}` which is incompatible with this crate's strategy of `{$desired_strategy}`
+
+metadata_multiple_names_in_link =
+    multiple `name` arguments in a single `#[link]` attribute
+
+metadata_multiple_kinds_in_link =
+    multiple `kind` arguments in a single `#[link]` attribute
+
+metadata_link_name_form =
+    link name must be of the form `name = "string"`
+
+metadata_link_kind_form =
+    link kind must be of the form `kind = "string"`
+
+metadata_link_modifiers_form =
+    link modifiers must be of the form `modifiers = "string"`
+
+metadata_link_cfg_form =
+    link cfg must be of the form `cfg(/* predicate */)`
+
+metadata_wasm_import_form =
+    wasm import module must be of the form `wasm_import_module = "string"`
+
+metadata_empty_link_name =
+    link name must not be empty
+    .label = empty link name
+
+metadata_link_framework_apple =
+    link kind `framework` is only supported on Apple targets
+
+metadata_framework_only_windows =
+    link kind `raw-dylib` is only supported on Windows targets
+
+metadata_unknown_link_kind =
+    unknown link kind `{$kind}`, expected one of: static, dylib, framework, raw-dylib
+    .label = unknown link kind
+
+metadata_multiple_link_modifiers =
+    multiple `modifiers` arguments in a single `#[link]` attribute
+
+metadata_multiple_cfgs =
+    multiple `cfg` arguments in a single `#[link]` attribute
+
+metadata_link_cfg_single_predicate =
+    link cfg must have a single predicate argument
+
+metadata_multiple_wasm_import =
+    multiple `wasm_import_module` arguments in a single `#[link]` attribute
+
+metadata_unexpected_link_arg =
+    unexpected `#[link]` argument, expected one of: name, kind, modifiers, cfg, wasm_import_module, import_name_type
+
+metadata_invalid_link_modifier =
+    invalid linking modifier syntax, expected '+' or '-' prefix before one of: bundle, verbatim, whole-archive, as-needed
+
+metadata_multiple_modifiers =
+    multiple `{$modifier}` modifiers in a single `modifiers` argument
+
+metadata_bundle_needs_static =
+    linking modifier `bundle` is only compatible with `static` linking kind
+
+metadata_whole_archive_needs_static =
+    linking modifier `whole-archive` is only compatible with `static` linking kind
+
+metadata_as_needed_compatibility =
+    linking modifier `as-needed` is only compatible with `dylib` and `framework` linking kinds
+
+metadata_unknown_link_modifier =
+    unknown linking modifier `{$modifier}`, expected one of: bundle, verbatim, whole-archive, as-needed
+
+metadata_incompatible_wasm_link =
+    `wasm_import_module` is incompatible with other arguments in `#[link]` attributes
+
+metadata_link_requires_name =
+    `#[link]` attribute requires a `name = "string"` argument
+    .label = missing `name` argument
+
+metadata_raw_dylib_no_nul =
+    link name must not contain NUL characters if link kind is `raw-dylib`
+
+metadata_link_ordinal_raw_dylib =
+    `#[link_ordinal]` is only supported if link kind is `raw-dylib`
+
+metadata_lib_framework_apple =
+    library kind `framework` is only supported on Apple targets
+
+metadata_empty_renaming_target =
+    an empty renaming target was specified for library `{$lib_name}`
+
+metadata_renaming_no_link =
+    renaming of the library `{$lib_name}` was specified, however this crate contains no `#[link(...)]` attributes referencing this library
+
+metadata_multiple_renamings =
+    multiple renamings were specified for library `{$lib_name}`
+
+metadata_no_link_mod_override =
+    overriding linking modifiers from command line is not supported
+
+metadata_unsupported_abi_i686 =
+    ABI not supported by `#[link(kind = "raw-dylib")]` on i686
+
+metadata_unsupported_abi =
+    ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture
+
+metadata_fail_create_file_encoder =
+    failed to create file encoder: {$err}
+
+metadata_fail_seek_file =
+    failed to seek the file: {$err}
+
+metadata_fail_write_file =
+    failed to write to the file: {$err}
+
+metadata_crate_not_panic_runtime =
+    the crate `{$crate_name}` is not a panic runtime
+
+metadata_no_panic_strategy =
+    the crate `{$crate_name}` does not have the panic strategy `{$strategy}`
+
+metadata_profiler_builtins_needs_core =
+    `profiler_builtins` crate (required by compiler options) is not compatible with crate attribute `#![no_core]`
+
+metadata_not_profiler_runtime =
+    the crate `{$crate_name}` is not a profiler runtime
+
+metadata_no_multiple_global_alloc =
+    cannot define multiple global allocators
+    .label = cannot define a new global allocator
+
+metadata_prev_global_alloc =
+    previous global allocator defined here
+
+metadata_conflicting_global_alloc =
+    the `#[global_allocator]` in {$other_crate_name} conflicts with global allocator in: {$crate_name}
+
+metadata_global_alloc_required =
+    no global memory allocator found but one is required; link to std or add `#[global_allocator]` to a static item that implements the GlobalAlloc trait
+
+metadata_no_transitive_needs_dep =
+    the crate `{$crate_name}` cannot depend on a crate that needs {$needs_crate_name}, but it depends on `{$deps_crate_name}`
+
+metadata_failed_write_error =
+    failed to write {$filename}: {$err}
+
+metadata_missing_native_library =
+    could not find native static library `{$libname}`, perhaps an -L flag is missing?
+
+metadata_failed_create_tempdir =
+    couldn't create a temp dir: {$err}
+
+metadata_failed_create_file =
+    failed to create the file {$filename}: {$err}
+
+metadata_failed_create_encoded_metadata =
+    failed to create encoded metadata from file: {$err}
+
+metadata_non_ascii_name =
+    cannot load a crate with a non-ascii name `{$crate_name}`
+
+metadata_extern_location_not_exist =
+    extern location for {$crate_name} does not exist: {$location}
+
+metadata_extern_location_not_file =
+    extern location for {$crate_name} is not a file: {$location}
+
+metadata_multiple_candidates =
+    multiple {$flavor} candidates for `{$crate_name}` found
+
+metadata_multiple_matching_crates =
+    multiple matching crates for `{$crate_name}`
+    .note = candidates:{$candidates}
+
+metadata_symbol_conflicts_current =
+    the current crate is indistinguishable from one of its dependencies: it has the same crate-name `{$crate_name}` and was compiled with the same `-C metadata` arguments. This will result in symbol conflicts between the two.
+
+metadata_symbol_conflicts_others =
+    found two different crates with name `{$crate_name}` that are not distinguished by differing `-C metadata`. This will result in symbol conflicts between the two.
+
+metadata_stable_crate_id_collision =
+    found crates (`{$crate_name0}` and `{$crate_name1}`) with colliding StableCrateId values.
+
+metadata_dl_error =
+    {$err}
+
+metadata_newer_crate_version =
+    found possibly newer version of crate `{$crate_name}`{$add_info}
+    .note = perhaps that crate needs to be recompiled?
+
+metadata_found_crate_versions =
+    the following crate versions were found:{$found_crates}
+
+metadata_no_crate_with_triple =
+    couldn't find crate `{$crate_name}` with expected target triple {$locator_triple}{$add_info}
+
+metadata_found_staticlib =
+    found staticlib `{$crate_name}` instead of rlib or dylib{$add_info}
+    .help = please recompile that crate using --crate-type lib
+
+metadata_incompatible_rustc =
+    found crate `{$crate_name}` compiled by an incompatible version of rustc{$add_info}
+    .help = please recompile that crate using this compiler ({$rustc_version}) (consider running `cargo clean` first)
+
+metadata_invalid_meta_files =
+    found invalid metadata files for crate `{$crate_name}`{$add_info}
+
+metadata_cannot_find_crate =
+    can't find crate for `{$crate_name}`{$add_info}
+
+metadata_no_dylib_plugin =
+    plugin `{$crate_name}` only found in rlib format, but must be available in dylib format
+
+metadata_target_not_installed =
+    the `{$locator_triple}` target may not be installed
+
+metadata_target_no_std_support =
+    the `{$locator_triple}` target may not support the standard library
+
+metadata_consider_downloading_target =
+    consider downloading the target with `rustup target add {$locator_triple}`
+
+metadata_std_required =
+    `std` is required by `{$current_crate}` because it does not declare `#![no_std]`
+
+metadata_consider_building_std =
+    consider building the standard library from source with `cargo build -Zbuild-std`
+
+metadata_compiler_missing_profiler =
+    the compiler may have been built without the profiler runtime
+
+metadata_install_missing_components =
+    maybe you need to install the missing components with: `rustup component add rust-src rustc-dev llvm-tools-preview`
+
+metadata_cant_find_crate =
+    can't find crate
+
+metadata_crate_location_unknown_type =
+    extern location for {$crate_name} is of an unknown type: {$path}
+
+metadata_lib_filename_form =
+    file name should be lib*.rlib or {dll_prefix}*.{dll_suffix}
+
+metadata_multiple_import_name_type =
+    multiple `import_name_type` arguments in a single `#[link]` attribute
+
+metadata_import_name_type_form =
+    import name type must be of the form `import_name_type = "string"`
+
+metadata_import_name_type_x86 =
+    import name type is only supported on x86
+
+metadata_unknown_import_name_type =
+    unknown import name type `{$import_name_type}`, expected one of: decorated, noprefix, undecorated
+
+metadata_import_name_type_raw =
+    import name type can only be used with link kind `raw-dylib`
diff --git a/compiler/rustc_error_messages/locales/en-US/middle.ftl b/compiler/rustc_error_messages/locales/en-US/middle.ftl
new file mode 100644
index 000000000000..ed834886453c
--- /dev/null
+++ b/compiler/rustc_error_messages/locales/en-US/middle.ftl
@@ -0,0 +1,17 @@
+middle_drop_check_overflow =
+    overflow while adding drop-check rules for {$ty}
+    .note = overflowed on {$overflow_ty}
+
+middle_opaque_hidden_type_mismatch =
+    concrete type differs from previous defining opaque type use
+    .label = expected `{$self_ty}`, got `{$other_ty}`
+
+middle_conflict_types =
+    this expression supplies two conflicting concrete types for the same opaque type
+
+middle_previous_use_here =
+    previous use here
+
+middle_limit_invalid =
+    `limit` must be a non-negative integer
+    .label = {$error_str}
diff --git a/compiler/rustc_error_messages/locales/en-US/parser.ftl b/compiler/rustc_error_messages/locales/en-US/parser.ftl
index 3b37a393846b..07dd03e6e504 100644
--- a/compiler/rustc_error_messages/locales/en-US/parser.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/parser.ftl
@@ -47,7 +47,7 @@ parser_invalid_comparison_operator = invalid comparison operator `{$invalid}`
     .spaceship_operator_invalid = `<=>` is not a valid comparison operator, use `std::cmp::Ordering`
 
 parser_invalid_logical_operator = `{$incorrect}` is not a logical operator
-    .note = unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+    .note = unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
     .use_amp_amp_for_conjunction = use `&&` to perform logical conjunction
     .use_pipe_pipe_for_disjunction = use `||` to perform logical disjunction
 
@@ -55,7 +55,9 @@ parser_tilde_is_not_unary_operator = `~` cannot be used as a unary operator
     .suggestion = use `!` to perform bitwise not
 
 parser_unexpected_token_after_not = unexpected {$negated_desc} after identifier
-    .suggestion = use `!` to perform logical negation
+parser_unexpected_token_after_not_bitwise = use `!` to perform bitwise not
+parser_unexpected_token_after_not_logical = use `!` to perform logical negation
+parser_unexpected_token_after_not_default = use `!` to perform logical negation or bitwise not
 
 parser_malformed_loop_label = malformed loop label
     .suggestion = use the correct loop label format
@@ -150,3 +152,12 @@ parser_dotdotdot = unexpected token: `...`
 
 parser_left_arrow_operator = unexpected token: `<-`
     .suggestion = if you meant to write a comparison against a negative value, add a space in between `<` and `-`
+
+parser_remove_let = expected pattern, found `let`
+    .suggestion = remove the unnecessary `let` keyword
+
+parser_use_eq_instead = unexpected `==`
+    .suggestion = try using `=` instead
+
+parser_use_empty_block_not_semi = expected { "`{}`" }, found `;`
+    .suggestion = try using { "`{}`" } instead
diff --git a/compiler/rustc_error_messages/locales/en-US/passes.ftl b/compiler/rustc_error_messages/locales/en-US/passes.ftl
index 7374f6d3f27d..995ad4fe2585 100644
--- a/compiler/rustc_error_messages/locales/en-US/passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/passes.ftl
@@ -265,3 +265,9 @@ passes_rustc_lint_opt_deny_field_access = `#[rustc_lint_opt_deny_field_access]`
 
 passes_link_ordinal = attribute should be applied to a foreign function or static
     .label = not a foreign function or static
+
+passes_collapse_debuginfo = `collapse_debuginfo` attribute should be applied to macro definitions
+    .label = not a macro definition
+
+passes_deprecated_annotation_has_no_effect = this `#[deprecated]` annotation has no effect
+    .suggestion = remove the unnecessary deprecation attribute
diff --git a/compiler/rustc_error_messages/locales/en-US/privacy.ftl b/compiler/rustc_error_messages/locales/en-US/privacy.ftl
index 223092a74bd9..a26d1b2b381e 100644
--- a/compiler/rustc_error_messages/locales/en-US/privacy.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/privacy.ftl
@@ -11,6 +11,8 @@ privacy_in_public_interface = {$vis_descr} {$kind} `{$descr}` in public interfac
     .label = can't leak {$vis_descr} {$kind}
     .visibility_label = `{$descr}` declared as {$vis_descr}
 
+privacy_report_effective_visibility = {$descr}
+
 privacy_from_private_dep_in_public_interface =
     {$kind} `{$descr}` from private dependency '{$krate}' in public interface
 
diff --git a/compiler/rustc_error_messages/locales/en-US/query_system.ftl b/compiler/rustc_error_messages/locales/en-US/query_system.ftl
new file mode 100644
index 000000000000..b914ba52a735
--- /dev/null
+++ b/compiler/rustc_error_messages/locales/en-US/query_system.ftl
@@ -0,0 +1,28 @@
+query_system_reentrant = internal compiler error: re-entrant incremental verify failure, suppressing message
+
+query_system_increment_compilation = internal compiler error: encountered incremental compilation error with {$dep_node}
+    .help = This is a known issue with the compiler. Run {$run_cmd} to allow your project to compile
+
+query_system_increment_compilation_note1 = Please follow the instructions below to create a bug report with the provided information
+query_system_increment_compilation_note2 = See <https://github.com/rust-lang/rust/issues/84970> for more information
+
+query_system_cycle = cycle detected when {$stack_bottom}
+
+query_system_cycle_usage = cycle used when {$usage}
+
+query_system_cycle_stack_single = ...which immediately requires {$stack_bottom} again
+
+query_system_cycle_stack_multiple = ...which again requires {$stack_bottom}, completing the cycle
+
+query_system_cycle_recursive_ty_alias = type aliases cannot be recursive
+query_system_cycle_recursive_ty_alias_help1 = consider using a struct, enum, or union instead to break the cycle
+query_system_cycle_recursive_ty_alias_help2 = see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information
+
+query_system_cycle_recursive_trait_alias = trait aliases cannot be recursive
+
+query_system_cycle_which_requires = ...which requires {$desc}...
+
+query_system_query_overflow = queries overflow the depth limit!
+    .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]` attribute to your crate (`{$crate_name}`)
+
+query_system_layout_of_depth = query depth increased by {$depth} when {$desc}
diff --git a/compiler/rustc_error_messages/locales/en-US/session.ftl b/compiler/rustc_error_messages/locales/en-US/session.ftl
index 983e5cee8237..76cae3c81e45 100644
--- a/compiler/rustc_error_messages/locales/en-US/session.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/session.ftl
@@ -14,3 +14,55 @@ session_feature_diagnostic_for_issue =
 
 session_feature_diagnostic_help =
     add `#![feature({$feature})]` to the crate attributes to enable
+
+session_not_circumvent_feature = `-Zunleash-the-miri-inside-of-you` may not be used to circumvent feature gates, except when testing error paths in the CTFE engine
+
+session_profile_use_file_does_not_exist = file `{$path}` passed to `-C profile-use` does not exist.
+
+session_linker_plugin_lto_windows_not_supported = linker plugin based LTO is not supported together with `-C prefer-dynamic` when targeting Windows-like targets
+
+session_profile_sample_use_file_does_not_exist = file `{$path}` passed to `-C profile-sample-use` does not exist.
+
+session_target_requires_unwind_tables = target requires unwind tables, they cannot be disabled with `-C force-unwind-tables=no`
+
+session_sanitizer_not_supported = {$us} sanitizer is not supported for this target
+
+session_sanitizers_not_supported = {$us} sanitizers are not supported for this target
+
+session_cannot_mix_and_match_sanitizers = `-Zsanitizer={$first}` is incompatible with `-Zsanitizer={$second}`
+
+session_cannot_enable_crt_static_linux = sanitizer is incompatible with statically linked libc, disable it using `-C target-feature=-crt-static`
+
+session_sanitizer_cfi_enabled = `-Zsanitizer=cfi` requires `-Clto`
+
+session_unstable_virtual_function_elimination = `-Zvirtual-function-elimination` requires `-Clto`
+
+session_unsupported_dwarf_version = requested DWARF version {$dwarf_version} is greater than 5
+
+session_target_invalid_address_space = invalid address space `{$addr_space}` for `{$cause}` in "data-layout": {$err}
+
+session_target_invalid_bits = invalid {$kind} `{$bit}` for `{$cause}` in "data-layout": {$err}
+
+session_target_missing_alignment = missing alignment for `{$cause}` in "data-layout"
+
+session_target_invalid_alignment = invalid alignment for `{$cause}` in "data-layout": {$err}
+
+session_target_inconsistent_architecture = inconsistent target specification: "data-layout" claims architecture is {$dl}-endian, while "target-endian" is `{$target}`
+
+session_target_inconsistent_pointer_width = inconsistent target specification: "data-layout" claims pointers are {$pointer_size}-bit, while "target-pointer-width" is `{$target}`
+
+session_target_invalid_bits_size = {$err}
+
+session_target_stack_protector_not_supported = `-Z stack-protector={$stack_protector}` is not supported for target {$target_triple} and will be ignored
+
+session_split_debuginfo_unstable_platform = `-Csplit-debuginfo={$debuginfo}` is unstable on this platform
+
+session_file_is_not_writeable = output file {$file} is not writeable -- check its permissions
+
+session_crate_name_does_not_match = `--crate-name` and `#[crate_name]` are required to match, but `{$s}` != `{$name}`
+
+session_crate_name_invalid = crate names cannot start with a `-`, but `{$s}` has a leading hyphen
+
+session_crate_name_empty = crate name must not be empty
+
+session_invalid_character_in_create_name = invalid character `{$character}` in crate name: `{$crate_name}`
diff --git a/compiler/rustc_error_messages/locales/en-US/symbol_mangling.ftl b/compiler/rustc_error_messages/locales/en-US/symbol_mangling.ftl
index 55d6fbbf86f3..b7d48280f461 100644
--- a/compiler/rustc_error_messages/locales/en-US/symbol_mangling.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/symbol_mangling.ftl
@@ -1,7 +1 @@
-symbol_mangling_invalid_symbol_name = symbol-name({$mangled_formatted})
-
-symbol_mangling_invalid_trait_item = demangling({$demangling_formatted})
-
-symbol_mangling_alt_invalid_trait_item = demangling-alt({$alt_demangling_formatted})
-
-symbol_mangling_invalid_def_path = def-path({$def_path})
+symbol_mangling_test_output = {$kind}({$content})
diff --git a/compiler/rustc_error_messages/locales/en-US/trait_selection.ftl b/compiler/rustc_error_messages/locales/en-US/trait_selection.ftl
new file mode 100644
index 000000000000..004e0ab18969
--- /dev/null
+++ b/compiler/rustc_error_messages/locales/en-US/trait_selection.ftl
@@ -0,0 +1,26 @@
+trait_selection_dump_vtable_entries = vtable entries for `{$trait_ref}`: {$entries}
+
+trait_selection_unable_to_construct_constant_value = unable to construct a constant value for the unevaluated constant {$unevaluated}
+
+trait_selection_auto_deref_reached_recursion_limit = reached the recursion limit while auto-dereferencing `{$ty}`
+    .label = deref recursion limit reached
+    .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]` attribute to your crate (`{$crate_name}`)
+
+trait_selection_empty_on_clause_in_rustc_on_unimplemented = empty `on`-clause in `#[rustc_on_unimplemented]`
+    .label = empty on-clause here
+
+trait_selection_invalid_on_clause_in_rustc_on_unimplemented = invalid `on`-clause in `#[rustc_on_unimplemented]`
+    .label = invalid on-clause here
+
+trait_selection_no_value_in_rustc_on_unimplemented = this attribute must have a valid value
+    .label = expected value here
+    .note = eg `#[rustc_on_unimplemented(message="foo")]`
+
+trait_selection_negative_positive_conflict = found both positive and negative implementation of trait `{$trait_desc}`{$self_desc ->
+        [none] {""}
+       *[default] {" "}for type `{$self_desc}`
+    }:
+    .negative_implementation_here = negative implementation here
+    .negative_implementation_in_crate = negative implementation in crate `{$negative_impl_cname}`
+    .positive_implementation_here = positive implementation here
+    .positive_implementation_in_crate = positive implementation in crate `{$positive_impl_cname}`
diff --git a/compiler/rustc_error_messages/src/lib.rs b/compiler/rustc_error_messages/src/lib.rs
index 42fb2d538b04..ff33ae7e8f22 100644
--- a/compiler/rustc_error_messages/src/lib.rs
+++ b/compiler/rustc_error_messages/src/lib.rs
@@ -5,6 +5,9 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
+#[macro_use]
+extern crate tracing;
+
 use fluent_bundle::FluentResource;
 use fluent_syntax::parser::ParserError;
 use rustc_data_structures::sync::Lrc;
@@ -16,7 +19,6 @@ use std::fmt;
 use std::fs;
 use std::io;
 use std::path::{Path, PathBuf};
-use tracing::{instrument, trace};
 
 #[cfg(not(parallel_compiler))]
 use std::cell::LazyCell as Lazy;
@@ -45,11 +47,15 @@ fluent_messages! {
     interface => "../locales/en-US/interface.ftl",
     infer => "../locales/en-US/infer.ftl",
     lint => "../locales/en-US/lint.ftl",
+    middle => "../locales/en-US/middle.ftl",
     monomorphize => "../locales/en-US/monomorphize.ftl",
+    metadata => "../locales/en-US/metadata.ftl",
     parser => "../locales/en-US/parser.ftl",
     passes => "../locales/en-US/passes.ftl",
     plugin_impl => "../locales/en-US/plugin_impl.ftl",
     privacy => "../locales/en-US/privacy.ftl",
+    query_system => "../locales/en-US/query_system.ftl",
+    trait_selection => "../locales/en-US/trait_selection.ftl",
     save_analysis => "../locales/en-US/save_analysis.ftl",
     ty_utils => "../locales/en-US/ty_utils.ftl",
     typeck => "../locales/en-US/typeck.ftl",
@@ -262,14 +268,14 @@ type FluentId = Cow<'static, str>;
 /// Translatable messages for subdiagnostics are typically attributes attached to a larger Fluent
 /// message so messages of this type must be combined with a `DiagnosticMessage` (using
 /// `DiagnosticMessage::with_subdiagnostic_message`) before rendering. However, subdiagnostics from
-/// the `SessionSubdiagnostic` derive refer to Fluent identifiers directly.
+/// the `Subdiagnostic` derive refer to Fluent identifiers directly.
 #[rustc_diagnostic_item = "SubdiagnosticMessage"]
 pub enum SubdiagnosticMessage {
     /// Non-translatable diagnostic message.
     // FIXME(davidtwco): can a `Cow<'static, str>` be used here?
     Str(String),
     /// Identifier of a Fluent message. Instances of this variant are generated by the
-    /// `SessionSubdiagnostic` derive.
+    /// `Subdiagnostic` derive.
     FluentIdentifier(FluentId),
     /// Attribute of a Fluent message. Needs to be combined with a Fluent identifier to produce an
     /// actual translated message. Instances of this variant are generated by the `fluent_messages`
diff --git a/compiler/rustc_errors/Cargo.toml b/compiler/rustc_errors/Cargo.toml
index 36805aa874fe..c36ca11fad6f 100644
--- a/compiler/rustc_errors/Cargo.toml
+++ b/compiler/rustc_errors/Cargo.toml
@@ -13,6 +13,7 @@ rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_target = { path = "../rustc_target" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
 unicode-width = "0.1.4"
@@ -20,8 +21,8 @@ atty = "0.2"
 termcolor = "1.0"
 annotate-snippets = "0.9"
 termize = "0.1.1"
-serde = { version = "1.0.125", features = ["derive"] }
+serde = { version = "1.0.125", features = [ "derive" ] }
 serde_json = "1.0.59"
 
 [target.'cfg(windows)'.dependencies]
-winapi = { version = "0.3", features = ["handleapi", "synchapi", "winbase"] }
+winapi = { version = "0.3", features = [ "handleapi", "synchapi", "winbase" ] }
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index f75e2596f361..1c440a0a07ef 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -10,9 +10,11 @@ use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_span::edition::LATEST_STABLE_EDITION;
 use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
 use rustc_span::{edition::Edition, Span, DUMMY_SP};
+use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
 use std::borrow::Cow;
 use std::fmt;
 use std::hash::{Hash, Hasher};
+use std::num::ParseIntError;
 use std::path::{Path, PathBuf};
 
 /// Error type for `Diagnostic`'s `suggestions` field, indicating that
@@ -33,7 +35,7 @@ pub enum DiagnosticArgValue<'source> {
     Number(usize),
 }
 
-/// Converts a value of a type into a `DiagnosticArg` (typically a field of a `SessionDiagnostic`
+/// Converts a value of a type into a `DiagnosticArg` (typically a field of an `IntoDiagnostic`
 /// struct). Implemented as a custom trait rather than `From` so that it is implemented on the type
 /// being converted rather than on `DiagnosticArgValue`, which enables types from other `rustc_*`
 /// crates to implement this.
@@ -90,6 +92,10 @@ into_diagnostic_arg_using_display!(
     Edition,
     Ident,
     MacroRulesNormalizedIdent,
+    ParseIntError,
+    StackProtector,
+    &TargetTriple,
+    SplitDebuginfo
 );
 
 impl IntoDiagnosticArg for bool {
@@ -144,6 +150,12 @@ impl IntoDiagnosticArg for usize {
     }
 }
 
+impl IntoDiagnosticArg for PanicStrategy {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
+    }
+}
+
 impl<'source> Into<FluentValue<'source>> for DiagnosticArgValue<'source> {
     fn into(self) -> FluentValue<'source> {
         match self {
@@ -164,9 +176,10 @@ impl IntoDiagnosticArg for hir::ConstContext {
 }
 
 /// Trait implemented by error types. This should not be implemented manually. Instead, use
-/// `#[derive(SessionSubdiagnostic)]` -- see [rustc_macros::SessionSubdiagnostic].
-#[rustc_diagnostic_item = "AddSubdiagnostic"]
-pub trait AddSubdiagnostic {
+/// `#[derive(Subdiagnostic)]` -- see [rustc_macros::Subdiagnostic].
+#[cfg_attr(bootstrap, rustc_diagnostic_item = "AddSubdiagnostic")]
+#[cfg_attr(not(bootstrap), rustc_diagnostic_item = "AddToDiagnostic")]
+pub trait AddToDiagnostic {
     /// Add a subdiagnostic to an existing diagnostic.
     fn add_to_diagnostic(self, diag: &mut Diagnostic);
 }
@@ -878,9 +891,9 @@ impl Diagnostic {
         self
     }
 
-    /// Add a subdiagnostic from a type that implements `SessionSubdiagnostic` - see
-    /// [rustc_macros::SessionSubdiagnostic].
-    pub fn subdiagnostic(&mut self, subdiagnostic: impl AddSubdiagnostic) -> &mut Self {
+    /// Add a subdiagnostic from a type that implements `Subdiagnostic` - see
+    /// [rustc_macros::Subdiagnostic].
+    pub fn subdiagnostic(&mut self, subdiagnostic: impl AddToDiagnostic) -> &mut Self {
         subdiagnostic.add_to_diagnostic(self);
         self
     }
@@ -974,12 +987,12 @@ impl Diagnostic {
     fn sub_with_highlights<M: Into<SubdiagnosticMessage>>(
         &mut self,
         level: Level,
-        mut message: Vec<(M, Style)>,
+        message: Vec<(M, Style)>,
         span: MultiSpan,
         render_span: Option<MultiSpan>,
     ) {
         let message = message
-            .drain(..)
+            .into_iter()
             .map(|m| (self.subdiagnostic_message_to_diagnostic_message(m.0), m.1))
             .collect();
         let sub = SubDiagnostic { level, message, span, render_span };
diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index 61d767a1cc6b..b4ba65ca96d3 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -12,7 +12,16 @@ use std::fmt::{self, Debug};
 use std::marker::PhantomData;
 use std::ops::{Deref, DerefMut};
 use std::thread::panicking;
-use tracing::debug;
+
+/// Trait implemented by error types. This should not be implemented manually. Instead, use
+/// `#[derive(Diagnostic)]` -- see [rustc_macros::Diagnostic].
+#[cfg_attr(bootstrap, rustc_diagnostic_item = "SessionDiagnostic")]
+#[cfg_attr(not(bootstrap), rustc_diagnostic_item = "IntoDiagnostic")]
+pub trait IntoDiagnostic<'a, T: EmissionGuarantee = ErrorGuaranteed> {
+    /// Write out as a diagnostic out of `Handler`.
+    #[must_use]
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, T>;
+}
 
 /// Used for emitting structured error messages and other diagnostic information.
 ///
@@ -571,7 +580,7 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
 
     forward!(pub fn subdiagnostic(
         &mut self,
-        subdiagnostic: impl crate::AddSubdiagnostic
+        subdiagnostic: impl crate::AddToDiagnostic
     ) -> &mut Self);
 }
 
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 6c1bfcb9919e..66fbb8f1213e 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -22,7 +22,7 @@ use crate::{
 
 use rustc_lint_defs::pluralize;
 
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::sync::Lrc;
 use rustc_error_messages::FluentArgs;
 use rustc_span::hygiene::{ExpnKind, MacroKind};
@@ -34,7 +34,6 @@ use std::iter;
 use std::path::Path;
 use termcolor::{Ansi, BufferWriter, ColorChoice, ColorSpec, StandardStream};
 use termcolor::{Buffer, Color, WriteColor};
-use tracing::*;
 
 /// Default column width, used in tests and when terminal dimensions cannot be determined.
 const DEFAULT_COLUMN_WIDTH: usize = 140;
@@ -1488,7 +1487,7 @@ impl EmitterWriter {
                 );
 
                 // Contains the vertical lines' positions for active multiline annotations
-                let mut multilines = FxHashMap::default();
+                let mut multilines = FxIndexMap::default();
 
                 // Get the left-side margin to remove it
                 let mut whitespace_margin = usize::MAX;
@@ -1705,7 +1704,7 @@ impl EmitterWriter {
         {
             notice_capitalization |= only_capitalization;
 
-            let has_deletion = parts.iter().any(|p| p.is_deletion());
+            let has_deletion = parts.iter().any(|p| p.is_deletion(sm));
             let is_multiline = complete.lines().count() > 1;
 
             if let Some(span) = span.primary_span() {
@@ -1881,16 +1880,23 @@ impl EmitterWriter {
                     let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display;
                     let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display;
 
+                    // If this addition is _only_ whitespace, then don't trim it,
+                    // or else we're just not rendering anything.
+                    let is_whitespace_addition = part.snippet.trim().is_empty();
+
                     // Do not underline the leading...
-                    let start = part.snippet.len().saturating_sub(part.snippet.trim_start().len());
+                    let start = if is_whitespace_addition {
+                        0
+                    } else {
+                        part.snippet.len().saturating_sub(part.snippet.trim_start().len())
+                    };
                     // ...or trailing spaces. Account for substitutions containing unicode
                     // characters.
-                    let sub_len: usize = part
-                        .snippet
-                        .trim()
-                        .chars()
-                        .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
-                        .sum();
+                    let sub_len: usize =
+                        if is_whitespace_addition { &part.snippet } else { part.snippet.trim() }
+                            .chars()
+                            .map(|ch| unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1))
+                            .sum();
 
                     let offset: isize = offsets
                         .iter()
@@ -2131,7 +2137,7 @@ impl EmitterWriter {
     }
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 enum DisplaySuggestion {
     Underline,
     Diff,
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 68abdd0bad1f..4d262ae0f5ec 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -7,12 +7,10 @@
 #![feature(if_let_guard)]
 #![feature(adt_const_params)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(never_type)]
 #![feature(result_option_inspect)]
 #![feature(rustc_attrs)]
 #![allow(incomplete_features)]
-#![allow(rustc::potential_query_instability)]
 
 #[macro_use]
 extern crate rustc_macros;
@@ -27,7 +25,7 @@ use Level::*;
 
 use emitter::{is_case_difference, Emitter, EmitterWriter};
 use registry::Registry;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_data_structures::sync::{self, Lock, Lrc};
 use rustc_data_structures::AtomicRef;
@@ -61,6 +59,7 @@ mod snippet;
 mod styled_buffer;
 pub mod translation;
 
+pub use diagnostic_builder::IntoDiagnostic;
 pub use snippet::Style;
 
 pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a, ErrorGuaranteed>>;
@@ -70,7 +69,7 @@ pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a, ErrorGuaranteed>>;
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 rustc_data_structures::static_assert_size!(PResult<'_, ()>, 16);
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(PResult<'_, bool>, 24);
+rustc_data_structures::static_assert_size!(PResult<'_, bool>, 16);
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, Encodable, Decodable)]
 pub enum SuggestionStyle {
@@ -151,21 +150,20 @@ pub struct SubstitutionHighlight {
 
 impl SubstitutionPart {
     pub fn is_addition(&self, sm: &SourceMap) -> bool {
-        !self.snippet.is_empty()
-            && sm
-                .span_to_snippet(self.span)
-                .map_or(self.span.is_empty(), |snippet| snippet.trim().is_empty())
+        !self.snippet.is_empty() && !self.replaces_meaningful_content(sm)
     }
 
-    pub fn is_deletion(&self) -> bool {
-        self.snippet.trim().is_empty()
+    pub fn is_deletion(&self, sm: &SourceMap) -> bool {
+        self.snippet.trim().is_empty() && self.replaces_meaningful_content(sm)
     }
 
     pub fn is_replacement(&self, sm: &SourceMap) -> bool {
-        !self.snippet.is_empty()
-            && sm
-                .span_to_snippet(self.span)
-                .map_or(!self.span.is_empty(), |snippet| !snippet.trim().is_empty())
+        !self.snippet.is_empty() && self.replaces_meaningful_content(sm)
+    }
+
+    fn replaces_meaningful_content(&self, sm: &SourceMap) -> bool {
+        sm.span_to_snippet(self.span)
+            .map_or(!self.span.is_empty(), |snippet| !snippet.trim().is_empty())
     }
 }
 
@@ -372,7 +370,7 @@ impl fmt::Display for ExplicitBug {
 impl error::Error for ExplicitBug {}
 
 pub use diagnostic::{
-    AddSubdiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgFromDisplay,
+    AddToDiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgFromDisplay,
     DiagnosticArgValue, DiagnosticId, DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
 };
 pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, LintDiagnosticBuilder};
@@ -413,7 +411,7 @@ struct HandlerInner {
     taught_diagnostics: FxHashSet<DiagnosticId>,
 
     /// Used to suggest rustc --explain <error code>
-    emitted_diagnostic_codes: FxHashSet<DiagnosticId>,
+    emitted_diagnostic_codes: FxIndexSet<DiagnosticId>,
 
     /// This set contains a hash of every diagnostic that has been emitted by
     /// this handler. These hashes is used to avoid emitting the same error
@@ -438,11 +436,11 @@ struct HandlerInner {
     /// have been converted.
     check_unstable_expect_diagnostics: bool,
 
-    /// Expected [`Diagnostic`]s store a [`LintExpectationId`] as part of
+    /// Expected [`Diagnostic`][diagnostic::Diagnostic]s store a [`LintExpectationId`] as part of
     /// the lint level. [`LintExpectationId`]s created early during the compilation
     /// (before `HirId`s have been defined) are not stable and can therefore not be
     /// stored on disk. This buffer stores these diagnostics until the ID has been
-    /// replaced by a stable [`LintExpectationId`]. The [`Diagnostic`]s are the
+    /// replaced by a stable [`LintExpectationId`]. The [`Diagnostic`][diagnostic::Diagnostic]s are the
     /// submitted for storage and added to the list of fulfilled expectations.
     unstable_expect_diagnostics: Vec<Diagnostic>,
 
@@ -456,7 +454,7 @@ struct HandlerInner {
 }
 
 /// A key denoting where from a diagnostic was stashed.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub enum StashKey {
     ItemNoType,
     UnderscoreForArrayLengths,
@@ -637,6 +635,10 @@ impl Handler {
         inner.steal((span, key)).map(|diag| DiagnosticBuilder::new_diagnostic(self, diag))
     }
 
+    pub fn has_stashed_diagnostic(&self, span: Span, key: StashKey) -> bool {
+        self.inner.borrow().stashed_diagnostics.get(&(span, key)).is_some()
+    }
+
     /// Emit all stashed diagnostics.
     pub fn emit_stashed_diagnostics(&self) -> Option<ErrorGuaranteed> {
         self.inner.borrow_mut().emit_stashed_diagnostics()
@@ -1026,6 +1028,39 @@ impl Handler {
         self.inner.borrow_mut().emit_diagnostic(diagnostic)
     }
 
+    pub fn emit_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> ErrorGuaranteed {
+        self.create_err(err).emit()
+    }
+
+    pub fn create_err<'a>(
+        &'a self,
+        err: impl IntoDiagnostic<'a>,
+    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+        err.into_diagnostic(self)
+    }
+
+    pub fn create_warning<'a>(
+        &'a self,
+        warning: impl IntoDiagnostic<'a, ()>,
+    ) -> DiagnosticBuilder<'a, ()> {
+        warning.into_diagnostic(self)
+    }
+
+    pub fn emit_warning<'a>(&'a self, warning: impl IntoDiagnostic<'a, ()>) {
+        self.create_warning(warning).emit()
+    }
+
+    pub fn create_fatal<'a>(
+        &'a self,
+        fatal: impl IntoDiagnostic<'a, !>,
+    ) -> DiagnosticBuilder<'a, !> {
+        fatal.into_diagnostic(self)
+    }
+
+    pub fn emit_fatal<'a>(&'a self, fatal: impl IntoDiagnostic<'a, !>) -> ! {
+        self.create_fatal(fatal).emit()
+    }
+
     fn emit_diag_at_span(
         &self,
         mut diag: Diagnostic,
@@ -1250,14 +1285,14 @@ impl HandlerInner {
 
     fn treat_err_as_bug(&self) -> bool {
         self.flags.treat_err_as_bug.map_or(false, |c| {
-            self.err_count()
-                + self.lint_err_count
-                + self.delayed_span_bugs.len()
-                + self.delayed_good_path_bugs.len()
-                >= c.get()
+            self.err_count() + self.lint_err_count + self.delayed_bug_count() >= c.get()
         })
     }
 
+    fn delayed_bug_count(&self) -> usize {
+        self.delayed_span_bugs.len() + self.delayed_good_path_bugs.len()
+    }
+
     fn print_error_count(&mut self, registry: &Registry) {
         self.emit_stashed_diagnostics();
 
@@ -1412,12 +1447,7 @@ impl HandlerInner {
         // incrementing `err_count` by one, so we need to +1 the comparing.
         // FIXME: Would be nice to increment err_count in a more coherent way.
         if self.flags.treat_err_as_bug.map_or(false, |c| {
-            self.err_count()
-                + self.lint_err_count
-                + self.delayed_span_bugs.len()
-                + self.delayed_good_path_bugs.len()
-                + 1
-                >= c.get()
+            self.err_count() + self.lint_err_count + self.delayed_bug_count() + 1 >= c.get()
         }) {
             // FIXME: don't abort here if report_delayed_bugs is off
             self.span_bug(sp, msg);
@@ -1518,14 +1548,24 @@ impl HandlerInner {
         if self.treat_err_as_bug() {
             match (
                 self.err_count() + self.lint_err_count,
+                self.delayed_bug_count(),
                 self.flags.treat_err_as_bug.map(|c| c.get()).unwrap_or(0),
             ) {
-                (1, 1) => panic!("aborting due to `-Z treat-err-as-bug=1`"),
-                (0 | 1, _) => {}
-                (count, as_bug) => panic!(
-                    "aborting after {} errors due to `-Z treat-err-as-bug={}`",
-                    count, as_bug,
-                ),
+                (1, 0, 1) => panic!("aborting due to `-Z treat-err-as-bug=1`"),
+                (0, 1, 1) => panic!("aborting due delayed bug with `-Z treat-err-as-bug=1`"),
+                (count, delayed_count, as_bug) => {
+                    if delayed_count > 0 {
+                        panic!(
+                            "aborting after {} errors and {} delayed bugs due to `-Z treat-err-as-bug={}`",
+                            count, delayed_count, as_bug,
+                        )
+                    } else {
+                        panic!(
+                            "aborting after {} errors due to `-Z treat-err-as-bug={}`",
+                            count, as_bug,
+                        )
+                    }
+                }
             }
         }
     }
diff --git a/compiler/rustc_errors/src/translation.rs b/compiler/rustc_errors/src/translation.rs
index 65338f56d9cc..4f407badb3f9 100644
--- a/compiler/rustc_errors/src/translation.rs
+++ b/compiler/rustc_errors/src/translation.rs
@@ -21,7 +21,7 @@ pub trait Translate {
     /// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
     /// passed around as a reference thereafter.
     fn to_fluent_args<'arg>(&self, args: &[DiagnosticArg<'arg>]) -> FluentArgs<'arg> {
-        FromIterator::from_iter(args.to_vec().drain(..))
+        FromIterator::from_iter(args.iter().cloned())
     }
 
     /// Convert `DiagnosticMessage`s to a string, performing translation if necessary.
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index 2bb522caa2d4..cd8a525e062c 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -10,11 +10,13 @@ use rustc_ast::{self as ast, AttrVec, Attribute, HasAttrs, Item, NodeId, PatKind
 use rustc_attr::{self as attr, Deprecation, Stability};
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::sync::{self, Lrc};
-use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, MultiSpan, PResult};
+use rustc_errors::{
+    Applicability, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic, MultiSpan, PResult,
+};
 use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT;
 use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics};
 use rustc_parse::{self, parser, MACRO_ARGUMENTS};
-use rustc_session::{parse::ParseSess, Limit, Session, SessionDiagnostic};
+use rustc_session::{parse::ParseSess, Limit, Session};
 use rustc_span::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
@@ -693,10 +695,6 @@ pub struct SyntaxExtension {
     pub span: Span,
     /// List of unstable features that are treated as stable inside this macro.
     pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
-    /// Suppresses the `unsafe_code` lint for code produced by this macro.
-    pub allow_internal_unsafe: bool,
-    /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
-    pub local_inner_macros: bool,
     /// The macro's stability info.
     pub stability: Option<Stability>,
     /// The macro's deprecation info.
@@ -708,6 +706,13 @@ pub struct SyntaxExtension {
     /// Built-in macros have a couple of special properties like availability
     /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
     pub builtin_name: Option<Symbol>,
+    /// Suppresses the `unsafe_code` lint for code produced by this macro.
+    pub allow_internal_unsafe: bool,
+    /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
+    pub local_inner_macros: bool,
+    /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
+    /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
+    pub collapse_debuginfo: bool,
 }
 
 impl SyntaxExtension {
@@ -729,14 +734,15 @@ impl SyntaxExtension {
         SyntaxExtension {
             span: DUMMY_SP,
             allow_internal_unstable: None,
-            allow_internal_unsafe: false,
-            local_inner_macros: false,
             stability: None,
             deprecation: None,
             helper_attrs: Vec::new(),
             edition,
             builtin_name: None,
             kind,
+            allow_internal_unsafe: false,
+            local_inner_macros: false,
+            collapse_debuginfo: false,
         }
     }
 
@@ -754,12 +760,13 @@ impl SyntaxExtension {
         let allow_internal_unstable =
             attr::allow_internal_unstable(sess, &attrs).collect::<Vec<Symbol>>();
 
-        let mut local_inner_macros = false;
-        if let Some(macro_export) = sess.find_by_name(attrs, sym::macro_export) {
-            if let Some(l) = macro_export.meta_item_list() {
-                local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
-            }
-        }
+        let allow_internal_unsafe = sess.contains_name(attrs, sym::allow_internal_unsafe);
+        let local_inner_macros = sess
+            .find_by_name(attrs, sym::macro_export)
+            .and_then(|macro_export| macro_export.meta_item_list())
+            .map_or(false, |l| attr::list_contains_name(&l, sym::local_inner_macros));
+        let collapse_debuginfo = sess.contains_name(attrs, sym::collapse_debuginfo);
+        tracing::debug!(?local_inner_macros, ?collapse_debuginfo, ?allow_internal_unsafe);
 
         let (builtin_name, helper_attrs) = sess
             .find_by_name(attrs, sym::rustc_builtin_macro)
@@ -801,13 +808,14 @@ impl SyntaxExtension {
             span,
             allow_internal_unstable: (!allow_internal_unstable.is_empty())
                 .then(|| allow_internal_unstable.into()),
-            allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe),
-            local_inner_macros,
             stability: stability.map(|(s, _)| s),
             deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d),
             helper_attrs,
             edition,
             builtin_name,
+            allow_internal_unsafe,
+            local_inner_macros,
+            collapse_debuginfo,
         }
     }
 
@@ -852,11 +860,12 @@ impl SyntaxExtension {
             call_site,
             self.span,
             self.allow_internal_unstable.clone(),
-            self.allow_internal_unsafe,
-            self.local_inner_macros,
             self.edition,
             macro_def_id,
             parent_module,
+            self.allow_internal_unsafe,
+            self.local_inner_macros,
+            self.collapse_debuginfo,
         )
     }
 }
@@ -1102,12 +1111,12 @@ impl<'a> ExtCtxt<'a> {
 
     pub fn create_err(
         &self,
-        err: impl SessionDiagnostic<'a>,
+        err: impl IntoDiagnostic<'a>,
     ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         self.sess.create_err(err)
     }
 
-    pub fn emit_err(&self, err: impl SessionDiagnostic<'a>) -> ErrorGuaranteed {
+    pub fn emit_err(&self, err: impl IntoDiagnostic<'a>) -> ErrorGuaranteed {
         self.sess.emit_err(err)
     }
 
diff --git a/compiler/rustc_expand/src/build.rs b/compiler/rustc_expand/src/build.rs
index c4890b4a9c41..50d2be3cee5e 100644
--- a/compiler/rustc_expand/src/build.rs
+++ b/compiler/rustc_expand/src/build.rs
@@ -178,8 +178,7 @@ impl<'a> ExtCtxt<'a> {
         ex: P<ast::Expr>,
     ) -> ast::Stmt {
         let pat = if mutbl {
-            let binding_mode = ast::BindingMode::ByValue(ast::Mutability::Mut);
-            self.pat_ident_binding_mode(sp, ident, binding_mode)
+            self.pat_ident_binding_mode(sp, ident, ast::BindingAnnotation::MUT)
         } else {
             self.pat_ident(sp, ident)
         };
@@ -445,17 +444,16 @@ impl<'a> ExtCtxt<'a> {
         self.pat(span, PatKind::Lit(expr))
     }
     pub fn pat_ident(&self, span: Span, ident: Ident) -> P<ast::Pat> {
-        let binding_mode = ast::BindingMode::ByValue(ast::Mutability::Not);
-        self.pat_ident_binding_mode(span, ident, binding_mode)
+        self.pat_ident_binding_mode(span, ident, ast::BindingAnnotation::NONE)
     }
 
     pub fn pat_ident_binding_mode(
         &self,
         span: Span,
         ident: Ident,
-        bm: ast::BindingMode,
+        ann: ast::BindingAnnotation,
     ) -> P<ast::Pat> {
-        let pat = PatKind::Ident(bm, ident.with_span_pos(span), None);
+        let pat = PatKind::Ident(ann, ident.with_span_pos(span), None);
         self.pat(span, pat)
     }
     pub fn pat_path(&self, span: Span, path: ast::Path) -> P<ast::Pat> {
@@ -618,7 +616,7 @@ impl<'a> ExtCtxt<'a> {
     }
 
     pub fn attribute(&self, mi: ast::MetaItem) -> ast::Attribute {
-        attr::mk_attr_outer(mi)
+        attr::mk_attr_outer(&self.sess.parse_sess.attr_id_generator, mi)
     }
 
     pub fn meta_word(&self, sp: Span, w: Symbol) -> ast::MetaItem {
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index 48ee23d2c3d1..8d4e36407486 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -2,9 +2,9 @@
 
 use rustc_ast::ptr::P;
 use rustc_ast::token::{Delimiter, Token, TokenKind};
-use rustc_ast::tokenstream::{AttrAnnotatedTokenStream, AttrAnnotatedTokenTree};
+use rustc_ast::tokenstream::{AttrTokenStream, AttrTokenTree};
 use rustc_ast::tokenstream::{DelimSpan, Spacing};
-use rustc_ast::tokenstream::{LazyTokenStream, TokenTree};
+use rustc_ast::tokenstream::{LazyAttrTokenStream, TokenTree};
 use rustc_ast::NodeId;
 use rustc_ast::{self as ast, AttrStyle, Attribute, HasAttrs, HasTokens, MetaItem};
 use rustc_attr as attr;
@@ -259,8 +259,8 @@ impl<'a> StripUnconfigured<'a> {
     fn try_configure_tokens<T: HasTokens>(&self, node: &mut T) {
         if self.config_tokens {
             if let Some(Some(tokens)) = node.tokens_mut() {
-                let attr_annotated_tokens = tokens.create_token_stream();
-                *tokens = LazyTokenStream::new(self.configure_tokens(&attr_annotated_tokens));
+                let attr_stream = tokens.to_attr_token_stream();
+                *tokens = LazyAttrTokenStream::new(self.configure_tokens(&attr_stream));
             }
         }
     }
@@ -270,16 +270,16 @@ impl<'a> StripUnconfigured<'a> {
         if self.in_cfg(&attrs) { Some(attrs) } else { None }
     }
 
-    /// Performs cfg-expansion on `stream`, producing a new `AttrAnnotatedTokenStream`.
+    /// Performs cfg-expansion on `stream`, producing a new `AttrTokenStream`.
     /// This is only used during the invocation of `derive` proc-macros,
     /// which require that we cfg-expand their entire input.
     /// Normal cfg-expansion operates on parsed AST nodes via the `configure` method
-    fn configure_tokens(&self, stream: &AttrAnnotatedTokenStream) -> AttrAnnotatedTokenStream {
-        fn can_skip(stream: &AttrAnnotatedTokenStream) -> bool {
-            stream.0.iter().all(|(tree, _spacing)| match tree {
-                AttrAnnotatedTokenTree::Attributes(_) => false,
-                AttrAnnotatedTokenTree::Token(_) => true,
-                AttrAnnotatedTokenTree::Delimited(_, _, inner) => can_skip(inner),
+    fn configure_tokens(&self, stream: &AttrTokenStream) -> AttrTokenStream {
+        fn can_skip(stream: &AttrTokenStream) -> bool {
+            stream.0.iter().all(|tree| match tree {
+                AttrTokenTree::Attributes(_) => false,
+                AttrTokenTree::Token(..) => true,
+                AttrTokenTree::Delimited(_, _, inner) => can_skip(inner),
             })
         }
 
@@ -290,36 +290,36 @@ impl<'a> StripUnconfigured<'a> {
         let trees: Vec<_> = stream
             .0
             .iter()
-            .flat_map(|(tree, spacing)| match tree.clone() {
-                AttrAnnotatedTokenTree::Attributes(mut data) => {
+            .flat_map(|tree| match tree.clone() {
+                AttrTokenTree::Attributes(mut data) => {
                     data.attrs.flat_map_in_place(|attr| self.process_cfg_attr(attr));
 
                     if self.in_cfg(&data.attrs) {
-                        data.tokens = LazyTokenStream::new(
-                            self.configure_tokens(&data.tokens.create_token_stream()),
+                        data.tokens = LazyAttrTokenStream::new(
+                            self.configure_tokens(&data.tokens.to_attr_token_stream()),
                         );
-                        Some((AttrAnnotatedTokenTree::Attributes(data), *spacing)).into_iter()
+                        Some(AttrTokenTree::Attributes(data)).into_iter()
                     } else {
                         None.into_iter()
                     }
                 }
-                AttrAnnotatedTokenTree::Delimited(sp, delim, mut inner) => {
+                AttrTokenTree::Delimited(sp, delim, mut inner) => {
                     inner = self.configure_tokens(&inner);
-                    Some((AttrAnnotatedTokenTree::Delimited(sp, delim, inner), *spacing))
+                    Some(AttrTokenTree::Delimited(sp, delim, inner))
                         .into_iter()
                 }
-                AttrAnnotatedTokenTree::Token(ref token) if let TokenKind::Interpolated(ref nt) = token.kind => {
+                AttrTokenTree::Token(ref token, _) if let TokenKind::Interpolated(ref nt) = token.kind => {
                     panic!(
                         "Nonterminal should have been flattened at {:?}: {:?}",
                         token.span, nt
                     );
                 }
-                AttrAnnotatedTokenTree::Token(token) => {
-                    Some((AttrAnnotatedTokenTree::Token(token), *spacing)).into_iter()
+                AttrTokenTree::Token(token, spacing) => {
+                    Some(AttrTokenTree::Token(token, spacing)).into_iter()
                 }
             })
             .collect();
-        AttrAnnotatedTokenStream::new(trees)
+        AttrTokenStream::new(trees)
     }
 
     /// Parse and expand all `cfg_attr` attributes into a list of attributes
@@ -388,7 +388,7 @@ impl<'a> StripUnconfigured<'a> {
         attr: &Attribute,
         (item, item_span): (ast::AttrItem, Span),
     ) -> Attribute {
-        let orig_tokens = attr.tokens().to_tokenstream();
+        let orig_tokens = attr.tokens();
 
         // We are taking an attribute of the form `#[cfg_attr(pred, attr)]`
         // and producing an attribute of the form `#[attr]`. We
@@ -404,27 +404,33 @@ impl<'a> StripUnconfigured<'a> {
         };
         let pound_span = pound_token.span;
 
-        let mut trees = vec![(AttrAnnotatedTokenTree::Token(pound_token), Spacing::Alone)];
+        let mut trees = vec![AttrTokenTree::Token(pound_token, Spacing::Alone)];
         if attr.style == AttrStyle::Inner {
             // For inner attributes, we do the same thing for the `!` in `#![some_attr]`
             let TokenTree::Token(bang_token @ Token { kind: TokenKind::Not, .. }, _) = orig_trees.next().unwrap() else {
                 panic!("Bad tokens for attribute {:?}", attr);
             };
-            trees.push((AttrAnnotatedTokenTree::Token(bang_token), Spacing::Alone));
+            trees.push(AttrTokenTree::Token(bang_token, Spacing::Alone));
         }
         // We don't really have a good span to use for the synthesized `[]`
         // in `#[attr]`, so just use the span of the `#` token.
-        let bracket_group = AttrAnnotatedTokenTree::Delimited(
+        let bracket_group = AttrTokenTree::Delimited(
             DelimSpan::from_single(pound_span),
             Delimiter::Bracket,
             item.tokens
                 .as_ref()
                 .unwrap_or_else(|| panic!("Missing tokens for {:?}", item))
-                .create_token_stream(),
+                .to_attr_token_stream(),
+        );
+        trees.push(bracket_group);
+        let tokens = Some(LazyAttrTokenStream::new(AttrTokenStream::new(trees)));
+        let attr = attr::mk_attr_from_item(
+            &self.sess.parse_sess.attr_id_generator,
+            item,
+            tokens,
+            attr.style,
+            item_span,
         );
-        trees.push((bracket_group, Spacing::Alone));
-        let tokens = Some(LazyTokenStream::new(AttrAnnotatedTokenStream::new(trees)));
-        let attr = attr::mk_attr_from_item(item, tokens, attr.style, item_span);
         if attr.has_name(sym::crate_type) {
             self.sess.parse_sess.buffer_lint(
                 rustc_lint_defs::builtin::DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
diff --git a/compiler/rustc_expand/src/errors.rs b/compiler/rustc_expand/src/errors.rs
index 0feae0debd22..bd93f0717f58 100644
--- a/compiler/rustc_expand/src/errors.rs
+++ b/compiler/rustc_expand/src/errors.rs
@@ -1,29 +1,29 @@
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 use rustc_span::symbol::MacroRulesNormalizedIdent;
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(expand::expr_repeat_no_syntax_vars)]
 pub(crate) struct NoSyntaxVarsExprRepeat {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(expand::must_repeat_once)]
 pub(crate) struct MustRepeatOnce {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(expand::count_repetition_misplaced)]
 pub(crate) struct CountRepetitionMisplaced {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(expand::meta_var_expr_unrecognized_var)]
 pub(crate) struct MetaVarExprUnrecognizedVar {
     #[primary_span]
@@ -31,7 +31,7 @@ pub(crate) struct MetaVarExprUnrecognizedVar {
     pub key: MacroRulesNormalizedIdent,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(expand::var_still_repeating)]
 pub(crate) struct VarStillRepeating {
     #[primary_span]
@@ -39,7 +39,7 @@ pub(crate) struct VarStillRepeating {
     pub ident: MacroRulesNormalizedIdent,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(expand::meta_var_dif_seq_matchers)]
 pub(crate) struct MetaVarsDifSeqMatchers {
     #[primary_span]
diff --git a/compiler/rustc_expand/src/lib.rs b/compiler/rustc_expand/src/lib.rs
index 75dcbd69674d..b34de94fb7db 100644
--- a/compiler/rustc_expand/src/lib.rs
+++ b/compiler/rustc_expand/src/lib.rs
@@ -3,7 +3,6 @@
 #![feature(associated_type_defaults)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(macro_metavar_expr)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_internals)]
@@ -15,6 +14,9 @@
 #[macro_use]
 extern crate rustc_macros;
 
+#[macro_use]
+extern crate tracing;
+
 extern crate proc_macro as pm;
 
 mod placeholders;
diff --git a/compiler/rustc_expand/src/mbe/macro_parser.rs b/compiler/rustc_expand/src/mbe/macro_parser.rs
index 4fa91dfeaea2..c8bdc39311c6 100644
--- a/compiler/rustc_expand/src/mbe/macro_parser.rs
+++ b/compiler/rustc_expand/src/mbe/macro_parser.rs
@@ -430,7 +430,7 @@ impl TtParser {
                     }
                 }
                 MatcherLoc::Delimited => {
-                    // Entering the delimeter is trivial.
+                    // Entering the delimiter is trivial.
                     mp.idx += 1;
                     self.cur_mps.push(mp);
                 }
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index e009e4f7c68d..6d2c7aac6af4 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -32,7 +32,6 @@ use rustc_span::Span;
 use std::borrow::Cow;
 use std::collections::hash_map::Entry;
 use std::{mem, slice};
-use tracing::debug;
 
 pub(crate) struct ParserAnyMacro<'a> {
     parser: Parser<'a>,
@@ -594,7 +593,7 @@ pub fn compile_declarative_macro(
     (mk_syn_ext(expander), rule_spans)
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum ExplainDocComment {
     #[label(expand::explain_doc_comment_inner)]
     Inner {
@@ -976,7 +975,7 @@ impl<'tt> TokenSet<'tt> {
         self.maybe_empty = false;
     }
 
-    // Adds `tok` to the set for `self`, marking sequence as non-empy.
+    // Adds `tok` to the set for `self`, marking sequence as non-empty.
     fn add_one(&mut self, tt: TtHandle<'tt>) {
         if !self.tokens.contains(&tt) {
             self.tokens.push(tt);
diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs
index beb33c05913c..59a7b668a83c 100644
--- a/compiler/rustc_expand/src/proc_macro_server.rs
+++ b/compiler/rustc_expand/src/proc_macro_server.rs
@@ -6,7 +6,7 @@ use rustc_ast::tokenstream::{self, Spacing::*, TokenStream};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
-use rustc_errors::{Diagnostic, MultiSpan, PResult};
+use rustc_errors::{MultiSpan, PResult};
 use rustc_parse::lexer::nfc_normalize;
 use rustc_parse::parse_stream_from_source_str;
 use rustc_session::parse::ParseSess;
@@ -15,7 +15,7 @@ use rustc_span::symbol::{self, sym, Symbol};
 use rustc_span::{BytePos, FileName, Pos, SourceFile, Span};
 
 use pm::bridge::{
-    server, DelimSpan, ExpnGlobals, Group, Ident, LitKind, Literal, Punct, TokenTree,
+    server, DelimSpan, Diagnostic, ExpnGlobals, Group, Ident, LitKind, Literal, Punct, TokenTree,
 };
 use pm::{Delimiter, Level, LineColumn};
 use std::ops::Bound;
@@ -368,8 +368,6 @@ impl server::Types for Rustc<'_, '_> {
     type FreeFunctions = FreeFunctions;
     type TokenStream = TokenStream;
     type SourceFile = Lrc<SourceFile>;
-    type MultiSpan = Vec<Span>;
-    type Diagnostic = Diagnostic;
     type Span = Span;
     type Symbol = Symbol;
 }
@@ -436,6 +434,21 @@ impl server::FreeFunctions for Rustc<'_, '_> {
             span: self.call_site,
         })
     }
+
+    fn emit_diagnostic(&mut self, diagnostic: Diagnostic<Self::Span>) {
+        let mut diag =
+            rustc_errors::Diagnostic::new(diagnostic.level.to_internal(), diagnostic.message);
+        diag.set_span(MultiSpan::from_spans(diagnostic.spans));
+        for child in diagnostic.children {
+            diag.sub(
+                child.level.to_internal(),
+                child.message,
+                MultiSpan::from_spans(child.spans),
+                None,
+            );
+        }
+        self.sess().span_diagnostic.emit_diagnostic(&mut diag);
+    }
 }
 
 impl server::TokenStream for Rustc<'_, '_> {
@@ -583,38 +596,6 @@ impl server::SourceFile for Rustc<'_, '_> {
     }
 }
 
-impl server::MultiSpan for Rustc<'_, '_> {
-    fn new(&mut self) -> Self::MultiSpan {
-        vec![]
-    }
-
-    fn push(&mut self, spans: &mut Self::MultiSpan, span: Self::Span) {
-        spans.push(span)
-    }
-}
-
-impl server::Diagnostic for Rustc<'_, '_> {
-    fn new(&mut self, level: Level, msg: &str, spans: Self::MultiSpan) -> Self::Diagnostic {
-        let mut diag = Diagnostic::new(level.to_internal(), msg);
-        diag.set_span(MultiSpan::from_spans(spans));
-        diag
-    }
-
-    fn sub(
-        &mut self,
-        diag: &mut Self::Diagnostic,
-        level: Level,
-        msg: &str,
-        spans: Self::MultiSpan,
-    ) {
-        diag.sub(level.to_internal(), msg, MultiSpan::from_spans(spans), None);
-    }
-
-    fn emit(&mut self, mut diag: Self::Diagnostic) {
-        self.sess().span_diagnostic.emit_diagnostic(&mut diag);
-    }
-}
-
 impl server::Span for Rustc<'_, '_> {
     fn debug(&mut self, span: Self::Span) -> String {
         if self.ecx.ecfg.span_debug {
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index c22adf77a27f..8efb7ccc1c71 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -161,6 +161,8 @@ declare_features! (
     (accepted, fn_must_use, "1.27.0", Some(43302), None),
     /// Allows capturing variables in scope using format_args!
     (accepted, format_args_capture, "1.58.0", Some(67984), None),
+    /// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
+    (accepted, generic_associated_types, "1.65.0", Some(44265), None),
     /// Allows attributes on lifetime/type formal parameters in generics (RFC 1327).
     (accepted, generic_param_attrs, "1.27.0", Some(48848), None),
     /// Allows the `#[global_allocator]` attribute.
@@ -187,7 +189,9 @@ declare_features! (
     /// especially around globs and shadowing (RFC 1560).
     (accepted, item_like_imports, "1.15.0", Some(35120), None),
     /// Allows `'a: { break 'a; }`.
-    (accepted, label_break_value, "CURRENT_RUSTC_VERSION", Some(48594), None),
+    (accepted, label_break_value, "1.65.0", Some(48594), None),
+    /// Allows `let...else` statements.
+    (accepted, let_else, "1.65.0", Some(87335), None),
     /// Allows `break {expr}` with a value inside `loop`s.
     (accepted, loop_break_value, "1.19.0", Some(37339), None),
     /// Allows use of `?` as the Kleene "at most one" operator in macros.
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index e09c3ccbc75a..71ad54291b28 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -221,6 +221,8 @@ declare_features! (
     (active, rustc_private, "1.0.0", Some(27812), None),
     /// Allows using internal rustdoc features like `doc(primitive)` or `doc(keyword)`.
     (active, rustdoc_internals, "1.58.0", Some(90418), None),
+    /// Allows using the `rustdoc::missing_doc_code_examples` lint
+    (active, rustdoc_missing_doc_code_examples, "1.31.0", Some(101730), None),
     /// Allows using `#[start]` on a function indicating that it is the program entrypoint.
     (active, start, "1.0.0", Some(29633), None),
     /// Allows using `#[structural_match]` which indicates that a type is structurally matchable.
@@ -310,6 +312,8 @@ declare_features! (
     (active, associated_type_defaults, "1.2.0", Some(29661), None),
     /// Allows `async || body` closures.
     (active, async_closure, "1.37.0", Some(62290), None),
+    /// Alows async functions to be declared, implemented, and used in traits.
+    (incomplete, async_fn_in_trait, "CURRENT_RUSTC_VERSION", Some(91611), None),
     /// Allows `extern "C-unwind" fn` to enable unwinding across ABI boundaries.
     (active, c_unwind, "1.52.0", Some(74990), None),
     /// Allows using C-variadics.
@@ -336,6 +340,8 @@ declare_features! (
     (active, closure_track_caller, "1.57.0", Some(87417), None),
     /// Allows to use the `#[cmse_nonsecure_entry]` attribute.
     (active, cmse_nonsecure_entry, "1.48.0", Some(75835), None),
+    /// Allows use of the `#[collapse_debuginfo]` attribute.
+    (active, collapse_debuginfo, "1.65.0", Some(100758), None),
     /// Allows `async {}` expressions in const contexts.
     (active, const_async_blocks, "1.53.0", Some(85368), None),
     // Allows limiting the evaluation steps of const expressions
@@ -380,6 +386,8 @@ declare_features! (
     (active, doc_cfg_hide, "1.57.0", Some(43781), None),
     /// Allows `#[doc(masked)]`.
     (active, doc_masked, "1.21.0", Some(44027), None),
+    /// Allows `dyn* Trait` objects.
+    (incomplete, dyn_star, "1.65.0", Some(91611), None),
     /// Allows `X..Y` patterns.
     (active, exclusive_range_pattern, "1.11.0", Some(37854), None),
     /// Allows exhaustive pattern matching on types that contain uninhabited types.
@@ -394,12 +402,12 @@ declare_features! (
     (active, ffi_returns_twice, "1.34.0", Some(58314), None),
     /// Allows using `#[repr(align(...))]` on function items
     (active, fn_align, "1.53.0", Some(82232), None),
+    /// Allows generators to be cloned.
+    (active, generator_clone, "1.65.0", Some(95360), None),
     /// Allows defining generators.
     (active, generators, "1.21.0", Some(43122), None),
     /// Infer generic args for both consts and types.
     (active, generic_arg_infer, "1.55.0", Some(85077), None),
-    /// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
-    (active, generic_associated_types, "1.23.0", Some(44265), None),
     /// An extension to the `generic_associated_types` feature, allowing incomplete features.
     (incomplete, generic_associated_types_extended, "1.61.0", Some(95451), None),
     /// Allows non-trivial generic constants which have to have wfness manually propagated to callers
@@ -424,8 +432,6 @@ declare_features! (
     (active, large_assignments, "1.52.0", Some(83518), None),
     /// Allows `if/while p && let q = r && ...` chains.
     (active, let_chains, "1.37.0", Some(53667), None),
-    /// Allows `let...else` statements.
-    (active, let_else, "1.56.0", Some(87335), None),
     /// Allows `#[link(..., cfg(..))]`.
     (active, link_cfg, "1.14.0", Some(37406), None),
     /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
@@ -478,7 +484,7 @@ declare_features! (
     /// Allows macro attributes on expressions, statements and non-inline modules.
     (active, proc_macro_hygiene, "1.30.0", Some(54727), None),
     /// Allows the use of raw-dylibs (RFC 2627).
-    (incomplete, raw_dylib, "1.40.0", Some(58713), None),
+    (active, raw_dylib, "1.65.0", Some(58713), None),
     /// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions.
     (active, raw_ref_op, "1.41.0", Some(64490), None),
     /// Allows using the `#[register_tool]` attribute.
@@ -487,6 +493,8 @@ declare_features! (
     (incomplete, repr128, "1.16.0", Some(56071), None),
     /// Allows `repr(simd)` and importing the various simd intrinsics.
     (active, repr_simd, "1.4.0", Some(27731), None),
+    /// Allows return-position `impl Trait` in traits.
+    (incomplete, return_position_impl_trait_in_trait, "1.65.0", Some(91611), None),
     /// Allows `extern "rust-cold"`.
     (active, rust_cold_cc, "1.63.0", Some(97544), None),
     /// Allows the use of SIMD types in functions declared in `extern` blocks.
@@ -519,6 +527,8 @@ declare_features! (
     /// Allows creation of instances of a struct by moving fields that have
     /// not changed from prior instances of the same struct (RFC #2528)
     (active, type_changing_struct_update, "1.58.0", Some(86555), None),
+    /// Enables rustc to generate code that instructs libstd to NOT ignore SIGPIPE.
+    (active, unix_sigpipe, "1.65.0", Some(97889), None),
     /// Allows unsized fn parameters.
     (active, unsized_fn_params, "1.49.0", Some(48055), None),
     /// Allows unsized rvalues at arguments and parameters.
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index 0487270b52a9..700d9dab64be 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -345,6 +345,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ungated!(link_section, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
     ungated!(no_mangle, Normal, template!(Word), WarnFollowing, @only_local: true),
     ungated!(used, Normal, template!(Word, List: "compiler|linker"), WarnFollowing, @only_local: true),
+    ungated!(link_ordinal, Normal, template!(List: "ordinal"), ErrorPreceding),
 
     // Limits:
     ungated!(recursion_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing),
@@ -359,6 +360,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
 
     // Entry point:
+    gated!(unix_sigpipe, Normal, template!(Word, NameValueStr: "inherit|sig_ign|sig_dfl"), ErrorFollowing, experimental!(unix_sigpipe)),
     ungated!(start, Normal, template!(Word), WarnFollowing),
     ungated!(no_start, CrateLevel, template!(Word), WarnFollowing),
     ungated!(no_main, CrateLevel, template!(Word), WarnFollowing),
@@ -405,10 +407,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
 
     // Linking:
     gated!(naked, Normal, template!(Word), WarnFollowing, @only_local: true, naked_functions, experimental!(naked)),
-    gated!(
-        link_ordinal, Normal, template!(List: "ordinal"), ErrorPreceding, raw_dylib,
-        experimental!(link_ordinal)
-    ),
 
     // Plugins:
     BuiltinAttribute {
@@ -470,7 +468,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     // RFC 2632
     gated!(
         const_trait, Normal, template!(Word), WarnFollowing, const_trait_impl,
-        "`const` is a temporary placeholder for marking a trait that is suitable for `const` \
+        "`const_trait` is a temporary placeholder for marking a trait that is suitable for `const` \
         `impls` and all default bodies as `const`, which may be removed or renamed in the \
         future."
     ),
@@ -480,6 +478,12 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         experimental!(deprecated_safe),
     ),
 
+    // `#[collapse_debuginfo]`
+    gated!(
+        collapse_debuginfo, Normal, template!(Word), WarnFollowing,
+        experimental!(collapse_debuginfo)
+    ),
+
     // ==========================================================================
     // Internal attributes: Stability, deprecation, and unsafe:
     // ==========================================================================
@@ -758,6 +762,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     // Internal attributes, Testing:
     // ==========================================================================
 
+    rustc_attr!(TEST, rustc_effective_visibility, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_outlives, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_capture_analysis, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_insignificant_dtor, Normal, template!(Word), WarnFollowing),
@@ -821,6 +826,14 @@ pub fn is_builtin_only_local(name: Symbol) -> bool {
     BUILTIN_ATTRIBUTE_MAP.get(&name).map_or(false, |attr| attr.only_local)
 }
 
+pub fn is_valid_for_get_attr(name: Symbol) -> bool {
+    BUILTIN_ATTRIBUTE_MAP.get(&name).map_or(false, |attr| match attr.duplicates {
+        WarnFollowing | ErrorFollowing | ErrorPreceding | FutureWarnFollowing
+        | FutureWarnPreceding => true,
+        DuplicatesOk | WarnFollowingWordOnly => false,
+    })
+}
+
 pub static BUILTIN_ATTRIBUTE_MAP: LazyLock<FxHashMap<Symbol, &BuiltinAttribute>> =
     LazyLock::new(|| {
         let mut map = FxHashMap::default();
diff --git a/compiler/rustc_feature/src/lib.rs b/compiler/rustc_feature/src/lib.rs
index e44c9291f848..bdaa0ee88eba 100644
--- a/compiler/rustc_feature/src/lib.rs
+++ b/compiler/rustc_feature/src/lib.rs
@@ -151,7 +151,7 @@ pub use active::{Features, ACTIVE_FEATURES, INCOMPATIBLE_FEATURES};
 pub use builtin_attrs::AttributeDuplicates;
 pub use builtin_attrs::{
     deprecated_attributes, find_gated_cfg, is_builtin_attr_name, is_builtin_only_local,
-    AttributeGate, AttributeTemplate, AttributeType, BuiltinAttribute, GatedCfg,
-    BUILTIN_ATTRIBUTES, BUILTIN_ATTRIBUTE_MAP,
+    is_valid_for_get_attr, AttributeGate, AttributeTemplate, AttributeType, BuiltinAttribute,
+    GatedCfg, BUILTIN_ATTRIBUTES, BUILTIN_ATTRIBUTE_MAP,
 };
 pub use removed::{REMOVED_FEATURES, STABLE_REMOVED_FEATURES};
diff --git a/compiler/rustc_feature/src/removed.rs b/compiler/rustc_feature/src/removed.rs
index 13f275bb6a0c..79a12801de29 100644
--- a/compiler/rustc_feature/src/removed.rs
+++ b/compiler/rustc_feature/src/removed.rs
@@ -164,7 +164,7 @@ declare_features! (
     (removed, quote, "1.33.0", Some(29601), None, None),
     (removed, reflect, "1.0.0", Some(27749), None, None),
     /// Allows using the `#[register_attr]` attribute.
-    (removed, register_attr, "CURRENT_RUSTC_VERSION", Some(66080), None,
+    (removed, register_attr, "1.65.0", Some(66080), None,
      Some("removed in favor of `#![register_tool]`")),
     /// Allows using the macros:
     /// + `__diagnostic_used`
diff --git a/compiler/rustc_hir/src/def.rs b/compiler/rustc_hir/src/def.rs
index 2d2648a8f35a..e7c26bd726fb 100644
--- a/compiler/rustc_hir/src/def.rs
+++ b/compiler/rustc_hir/src/def.rs
@@ -109,6 +109,8 @@ pub enum DefKind {
     InlineConst,
     /// Opaque type, aka `impl Trait`.
     OpaqueTy,
+    /// A return-position `impl Trait` in a trait definition
+    ImplTraitPlaceholder,
     Field,
     /// Lifetime parameter: the `'a` in `struct Foo<'a> { ... }`
     LifetimeParam,
@@ -138,6 +140,7 @@ impl DefKind {
                 panic!("impossible struct constructor")
             }
             DefKind::OpaqueTy => "opaque type",
+            DefKind::ImplTraitPlaceholder => "opaque type in trait",
             DefKind::TyAlias => "type alias",
             DefKind::TraitAlias => "trait alias",
             DefKind::AssocTy => "associated type",
@@ -217,7 +220,8 @@ impl DefKind {
             | DefKind::Use
             | DefKind::ForeignMod
             | DefKind::GlobalAsm
-            | DefKind::Impl => None,
+            | DefKind::Impl
+            | DefKind::ImplTraitPlaceholder => None,
         }
     }
 
@@ -254,6 +258,7 @@ impl DefKind {
             | DefKind::Use
             | DefKind::ForeignMod
             | DefKind::OpaqueTy
+            | DefKind::ImplTraitPlaceholder
             | DefKind::Impl
             | DefKind::Field
             | DefKind::TyParam
@@ -308,6 +313,7 @@ pub enum Res<Id = hir::HirId> {
     ///
     /// **Belongs to the type namespace.**
     PrimTy(hir::PrimTy),
+
     /// The `Self` type, optionally with the [`DefId`] of the trait it belongs to and
     /// optionally with the [`DefId`] of the item introducing the `Self` type alias.
     ///
@@ -355,7 +361,8 @@ pub enum Res<Id = hir::HirId> {
     /// const fn baz<T>() -> usize { 10 }
     /// ```
     /// We do however allow `Self` in repeat expression even if it is generic to not break code
-    /// which already works on stable while causing the `const_evaluatable_unchecked` future compat lint:
+    /// which already works on stable while causing the `const_evaluatable_unchecked` future compat
+    /// lint:
     /// ```
     /// fn foo<T>() {
     ///     let _bar = [1_u8; std::mem::size_of::<*mut T>()];
@@ -370,6 +377,7 @@ pub enum Res<Id = hir::HirId> {
         /// from mentioning generics (i.e. when used in an anonymous constant).
         alias_to: Option<(DefId, bool)>,
     },
+
     /// A tool attribute module; e.g., the `rustfmt` in `#[rustfmt::skip]`.
     ///
     /// **Belongs to the type namespace.**
@@ -383,6 +391,7 @@ pub enum Res<Id = hir::HirId> {
     ///
     /// *See also [`Res::SelfTy`].*
     SelfCtor(DefId),
+
     /// A local variable or function parameter.
     ///
     /// **Belongs to the value namespace.**
@@ -453,7 +462,7 @@ impl PartialRes {
 
 /// Different kinds of symbols can coexist even if they share the same textual name.
 /// Therefore, they each have a separate universe (known as a "namespace").
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub enum Namespace {
     /// The type namespace includes `struct`s, `enum`s, `union`s, `trait`s, and `mod`s
     /// (and, by extension, crates).
diff --git a/compiler/rustc_hir/src/definitions.rs b/compiler/rustc_hir/src/definitions.rs
index c2c551e78a41..d85ac960f9b2 100644
--- a/compiler/rustc_hir/src/definitions.rs
+++ b/compiler/rustc_hir/src/definitions.rs
@@ -15,7 +15,6 @@ use rustc_span::symbol::{kw, sym, Symbol};
 
 use std::fmt::{self, Write};
 use std::hash::Hash;
-use tracing::debug;
 
 /// The `DefPathTable` maps `DefIndex`es to `DefKey`s and vice versa.
 /// Internally the `DefPathTable` holds a tree of `DefKey`s, where each `DefKey`
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index a069c49b0cc1..c1948052e3c5 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -1,13 +1,13 @@
 use crate::def::{CtorKind, DefKind, Res};
 use crate::def_id::DefId;
-pub(crate) use crate::hir_id::{HirId, ItemLocalId};
+pub(crate) use crate::hir_id::{HirId, ItemLocalId, OwnerId};
 use crate::intravisit::FnKind;
 use crate::LangItem;
 
 use rustc_ast as ast;
 use rustc_ast::util::parser::ExprPrecedence;
 use rustc_ast::{Attribute, FloatTy, IntTy, Label, LitKind, TraitObjectSyntax, UintTy};
-pub use rustc_ast::{BorrowKind, ImplPolarity, IsAuto};
+pub use rustc_ast::{BindingAnnotation, BorrowKind, ByRef, ImplPolarity, IsAuto};
 pub use rustc_ast::{CaptureBy, Movability, Mutability};
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_data_structures::fingerprint::Fingerprint;
@@ -139,11 +139,10 @@ impl LifetimeName {
         match self {
             LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Infer => true,
 
-            // It might seem surprising that `Fresh` counts as
-            // *not* elided -- but this is because, as far as the code
-            // in the compiler is concerned -- `Fresh` variants act
-            // equivalently to "some fresh name". They correspond to
-            // early-bound regions on an impl, in other words.
+            // It might seem surprising that `Fresh` counts as not *elided*
+            // -- but this is because, as far as the code in the compiler is
+            // concerned -- `Fresh` variants act equivalently to "some fresh name".
+            // They correspond to early-bound regions on an impl, in other words.
             LifetimeName::Error | LifetimeName::Param(..) | LifetimeName::Static => false,
         }
     }
@@ -202,13 +201,8 @@ impl Path<'_> {
 pub struct PathSegment<'hir> {
     /// The identifier portion of this path segment.
     pub ident: Ident,
-    // `id` and `res` are optional. We currently only use these in save-analysis,
-    // any path segments without these will not have save-analysis info and
-    // therefore will not have 'jump to def' in IDEs, but otherwise will not be
-    // affected. (In general, we don't bother to get the defs for synthesized
-    // segments, only for segments which have come from the AST).
-    pub hir_id: Option<HirId>,
-    pub res: Option<Res>,
+    pub hir_id: HirId,
+    pub res: Res,
 
     /// Type/lifetime parameters attached to this path. They come in
     /// two flavors: `Path<A,B,C>` and `Path(A,B) -> C`. Note that
@@ -226,12 +220,12 @@ pub struct PathSegment<'hir> {
 
 impl<'hir> PathSegment<'hir> {
     /// Converts an identifier to the corresponding segment.
-    pub fn from_ident(ident: Ident) -> PathSegment<'hir> {
-        PathSegment { ident, hir_id: None, res: None, infer_args: true, args: None }
+    pub fn new(ident: Ident, hir_id: HirId, res: Res) -> PathSegment<'hir> {
+        PathSegment { ident, hir_id, res, infer_args: true, args: None }
     }
 
     pub fn invalid() -> Self {
-        Self::from_ident(Ident::empty())
+        Self::new(Ident::empty(), HirId::INVALID, Res::Err)
     }
 
     pub fn args(&self) -> &GenericArgs<'hir> {
@@ -264,8 +258,8 @@ impl InferArg {
 
 #[derive(Debug, HashStable_Generic)]
 pub enum GenericArg<'hir> {
-    Lifetime(Lifetime),
-    Type(Ty<'hir>),
+    Lifetime(&'hir Lifetime),
+    Type(&'hir Ty<'hir>),
     Const(ConstArg),
     Infer(InferArg),
 }
@@ -280,7 +274,7 @@ impl GenericArg<'_> {
         }
     }
 
-    pub fn id(&self) -> HirId {
+    pub fn hir_id(&self) -> HirId {
         match self {
             GenericArg::Lifetime(l) => l.hir_id,
             GenericArg::Type(t) => t.hir_id,
@@ -305,9 +299,9 @@ impl GenericArg<'_> {
     pub fn to_ord(&self) -> ast::ParamKindOrd {
         match self {
             GenericArg::Lifetime(_) => ast::ParamKindOrd::Lifetime,
-            GenericArg::Type(_) => ast::ParamKindOrd::Type,
-            GenericArg::Const(_) => ast::ParamKindOrd::Const,
-            GenericArg::Infer(_) => ast::ParamKindOrd::Infer,
+            GenericArg::Type(_) | GenericArg::Const(_) | GenericArg::Infer(_) => {
+                ast::ParamKindOrd::TypeOrConst
+            }
         }
     }
 
@@ -435,7 +429,7 @@ pub enum GenericBound<'hir> {
     Trait(PolyTraitRef<'hir>, TraitBoundModifier),
     // FIXME(davidtwco): Introduce `PolyTraitRef::LangItem`
     LangItemTrait(LangItem, Span, HirId, &'hir GenericArgs<'hir>),
-    Outlives(Lifetime),
+    Outlives(&'hir Lifetime),
 }
 
 impl GenericBound<'_> {
@@ -581,8 +575,7 @@ impl<'hir> Generics<'hir> {
         if self.has_where_clause_predicates {
             self.predicates
                 .iter()
-                .filter(|p| p.in_where_clause())
-                .last()
+                .rfind(|&p| p.in_where_clause())
                 .map_or(end, |p| p.span())
                 .shrink_to_hi()
                 .to(end)
@@ -761,7 +754,7 @@ impl<'hir> WhereBoundPredicate<'hir> {
 pub struct WhereRegionPredicate<'hir> {
     pub span: Span,
     pub in_where_clause: bool,
-    pub lifetime: Lifetime,
+    pub lifetime: &'hir Lifetime,
     pub bounds: GenericBounds<'hir>,
 }
 
@@ -840,7 +833,16 @@ impl<'tcx> OwnerNodes<'tcx> {
 impl fmt::Debug for OwnerNodes<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("OwnerNodes")
+            // Do not print all the pointers to all the nodes, as it would be unreadable.
             .field("node", &self.nodes[ItemLocalId::from_u32(0)])
+            .field(
+                "parents",
+                &self
+                    .nodes
+                    .iter_enumerated()
+                    .map(|(id, parented_node)| (id, parented_node.as_ref().map(|node| node.parent)))
+                    .collect::<Vec<_>>(),
+            )
             .field("bodies", &self.bodies)
             .field("local_id_to_def_id", &self.local_id_to_def_id)
             .field("hash_without_bodies", &self.hash_without_bodies)
@@ -1049,30 +1051,6 @@ pub struct PatField<'hir> {
     pub span: Span,
 }
 
-/// Explicit binding annotations given in the HIR for a binding. Note
-/// that this is not the final binding *mode* that we infer after type
-/// inference.
-#[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
-pub enum BindingAnnotation {
-    /// No binding annotation given: this means that the final binding mode
-    /// will depend on whether we have skipped through a `&` reference
-    /// when matching. For example, the `x` in `Some(x)` will have binding
-    /// mode `None`; if you do `let Some(x) = &Some(22)`, it will
-    /// ultimately be inferred to be by-reference.
-    ///
-    /// Note that implicit reference skipping is not implemented yet (#42640).
-    Unannotated,
-
-    /// Annotated with `mut x` -- could be either ref or not, similar to `None`.
-    Mutable,
-
-    /// Annotated as `ref`, like `ref x`
-    Ref,
-
-    /// Annotated as `ref mut x`.
-    RefMut,
-}
-
 #[derive(Copy, Clone, PartialEq, Encodable, Debug, HashStable_Generic)]
 pub enum RangeEnd {
     Included,
@@ -1088,6 +1066,35 @@ impl fmt::Display for RangeEnd {
     }
 }
 
+// Equivalent to `Option<usize>`. That type takes up 16 bytes on 64-bit, but
+// this type only takes up 4 bytes, at the cost of being restricted to a
+// maximum value of `u32::MAX - 1`. In practice, this is more than enough.
+#[derive(Clone, Copy, PartialEq, Eq, Hash, HashStable_Generic)]
+pub struct DotDotPos(u32);
+
+impl DotDotPos {
+    // Panics if n >= u32::MAX.
+    pub fn new(n: Option<usize>) -> Self {
+        match n {
+            Some(n) => {
+                assert!(n < u32::MAX as usize);
+                Self(n as u32)
+            }
+            None => Self(u32::MAX),
+        }
+    }
+
+    pub fn as_opt_usize(&self) -> Option<usize> {
+        if self.0 == u32::MAX { None } else { Some(self.0 as usize) }
+    }
+}
+
+impl fmt::Debug for DotDotPos {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.as_opt_usize().fmt(f)
+    }
+}
+
 #[derive(Debug, HashStable_Generic)]
 pub enum PatKind<'hir> {
     /// Represents a wildcard pattern (i.e., `_`).
@@ -1104,9 +1111,9 @@ pub enum PatKind<'hir> {
     Struct(QPath<'hir>, &'hir [PatField<'hir>], bool),
 
     /// A tuple struct/variant pattern `Variant(x, y, .., z)`.
-    /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
+    /// If the `..` pattern fragment is present, then `DotDotPos` denotes its position.
     /// `0 <= position <= subpats.len()`
-    TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], Option<usize>),
+    TupleStruct(QPath<'hir>, &'hir [Pat<'hir>], DotDotPos),
 
     /// An or-pattern `A | B | C`.
     /// Invariant: `pats.len() >= 2`.
@@ -1118,7 +1125,7 @@ pub enum PatKind<'hir> {
     /// A tuple pattern (e.g., `(a, b)`).
     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
     /// `0 <= position <= subpats.len()`
-    Tuple(&'hir [Pat<'hir>], Option<usize>),
+    Tuple(&'hir [Pat<'hir>], DotDotPos),
 
     /// A `box` pattern.
     Box(&'hir Pat<'hir>),
@@ -1321,7 +1328,7 @@ pub enum StmtKind<'hir> {
     Semi(&'hir Expr<'hir>),
 }
 
-/// Represents a `let` statement (i.e., `let <pat>:<ty> = <expr>;`).
+/// Represents a `let` statement (i.e., `let <pat>:<ty> = <init>;`).
 #[derive(Debug, HashStable_Generic)]
 pub struct Local<'hir> {
     pub pat: &'hir Pat<'hir>,
@@ -1438,7 +1445,7 @@ pub struct BodyId {
 #[derive(Debug, HashStable_Generic)]
 pub struct Body<'hir> {
     pub params: &'hir [Param<'hir>],
-    pub value: Expr<'hir>,
+    pub value: &'hir Expr<'hir>,
     pub generator_kind: Option<GeneratorKind>,
 }
 
@@ -1881,11 +1888,11 @@ pub enum ExprKind<'hir> {
     ///
     /// The `PathSegment` represents the method name and its generic arguments
     /// (within the angle brackets).
-    /// The first element of the `&[Expr]` is the expression that evaluates
+    /// The `&Expr` is the expression that evaluates
     /// to the object on which the method is being called on (the receiver),
-    /// and the remaining elements are the rest of the arguments.
+    /// and the `&[Expr]` is the rest of the arguments.
     /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
-    /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d], span)`.
+    /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, x, [a, b, c, d], span)`.
     /// The final `Span` represents the span of the function and arguments
     /// (e.g. `foo::<Bar, Baz>(a, b, c, d)` in `x.foo::<Bar, Baz>(a, b, c, d)`
     ///
@@ -1893,7 +1900,7 @@ pub enum ExprKind<'hir> {
     /// the `hir_id` of the `MethodCall` node itself.
     ///
     /// [`type_dependent_def_id`]: ../../rustc_middle/ty/struct.TypeckResults.html#method.type_dependent_def_id
-    MethodCall(&'hir PathSegment<'hir>, &'hir [Expr<'hir>], Span),
+    MethodCall(&'hir PathSegment<'hir>, &'hir Expr<'hir>, &'hir [Expr<'hir>], Span),
     /// A tuple (e.g., `(a, b, c, d)`).
     Tup(&'hir [Expr<'hir>]),
     /// A binary operation (e.g., `a + b`, `a * b`).
@@ -2199,14 +2206,14 @@ pub struct FnSig<'hir> {
 // so it can fetched later.
 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct TraitItemId {
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
 }
 
 impl TraitItemId {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 }
 
@@ -2217,7 +2224,7 @@ impl TraitItemId {
 #[derive(Debug, HashStable_Generic)]
 pub struct TraitItem<'hir> {
     pub ident: Ident,
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
     pub generics: &'hir Generics<'hir>,
     pub kind: TraitItemKind<'hir>,
     pub span: Span,
@@ -2228,7 +2235,7 @@ impl TraitItem<'_> {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 
     pub fn trait_item_id(&self) -> TraitItemId {
@@ -2263,14 +2270,14 @@ pub enum TraitItemKind<'hir> {
 // so it can fetched later.
 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct ImplItemId {
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
 }
 
 impl ImplItemId {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 }
 
@@ -2278,7 +2285,7 @@ impl ImplItemId {
 #[derive(Debug, HashStable_Generic)]
 pub struct ImplItem<'hir> {
     pub ident: Ident,
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
     pub generics: &'hir Generics<'hir>,
     pub kind: ImplItemKind<'hir>,
     pub defaultness: Defaultness,
@@ -2290,7 +2297,7 @@ impl ImplItem<'_> {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 
     pub fn impl_item_id(&self) -> ImplItemId {
@@ -2401,6 +2408,14 @@ impl<'hir> Ty<'hir> {
             _ => None,
         }
     }
+
+    pub fn peel_refs(&self) -> &Self {
+        let mut final_ty = self;
+        while let TyKind::Rptr(_, MutTy { ty, .. }) = &final_ty.kind {
+            final_ty = &ty;
+        }
+        final_ty
+    }
 }
 
 /// Not represented directly in the AST; referred to by name through a `ty_path`.
@@ -2505,6 +2520,7 @@ pub struct OpaqueTy<'hir> {
     pub generics: &'hir Generics<'hir>,
     pub bounds: GenericBounds<'hir>,
     pub origin: OpaqueTyOrigin,
+    pub in_trait: bool,
 }
 
 /// From whence the opaque type came.
@@ -2528,7 +2544,7 @@ pub enum TyKind<'hir> {
     /// A raw pointer (i.e., `*const T` or `*mut T`).
     Ptr(MutTy<'hir>),
     /// A reference (i.e., `&'a T` or `&'a mut T`).
-    Rptr(Lifetime, MutTy<'hir>),
+    Rptr(&'hir Lifetime, MutTy<'hir>),
     /// A bare function (e.g., `fn(usize) -> bool`).
     BareFn(&'hir BareFnTy<'hir>),
     /// The never type (`!`).
@@ -2544,10 +2560,12 @@ pub enum TyKind<'hir> {
     ///
     /// The generic argument list contains the lifetimes (and in the future
     /// possibly parameters) that are actually bound on the `impl Trait`.
-    OpaqueDef(ItemId, &'hir [GenericArg<'hir>]),
+    ///
+    /// The last parameter specifies whether this opaque appears in a trait definition.
+    OpaqueDef(ItemId, &'hir [GenericArg<'hir>], bool),
     /// A trait object type `Bound1 + Bound2 + Bound3`
     /// where `Bound` is a trait or a lifetime.
-    TraitObject(&'hir [PolyTraitRef<'hir>], Lifetime, TraitObjectSyntax),
+    TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
     /// Unused for now.
     Typeof(AnonConst),
     /// `TyKind::Infer` means the type should be inferred instead of it having been
@@ -2561,23 +2579,23 @@ pub enum TyKind<'hir> {
 pub enum InlineAsmOperand<'hir> {
     In {
         reg: InlineAsmRegOrRegClass,
-        expr: Expr<'hir>,
+        expr: &'hir Expr<'hir>,
     },
     Out {
         reg: InlineAsmRegOrRegClass,
         late: bool,
-        expr: Option<Expr<'hir>>,
+        expr: Option<&'hir Expr<'hir>>,
     },
     InOut {
         reg: InlineAsmRegOrRegClass,
         late: bool,
-        expr: Expr<'hir>,
+        expr: &'hir Expr<'hir>,
     },
     SplitInOut {
         reg: InlineAsmRegOrRegClass,
         late: bool,
-        in_expr: Expr<'hir>,
-        out_expr: Option<Expr<'hir>>,
+        in_expr: &'hir Expr<'hir>,
+        out_expr: Option<&'hir Expr<'hir>>,
     },
     Const {
         anon_const: AnonConst,
@@ -2642,7 +2660,7 @@ pub struct FnDecl<'hir> {
 }
 
 /// Represents what type of implicit self a function has, if any.
-#[derive(Copy, Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum ImplicitSelfKind {
     /// Represents a `fn x(self);`.
     Imm,
@@ -2870,14 +2888,14 @@ impl<'hir> VariantData<'hir> {
 // so it can fetched later.
 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, Hash, HashStable_Generic)]
 pub struct ItemId {
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
 }
 
 impl ItemId {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 }
 
@@ -2887,7 +2905,7 @@ impl ItemId {
 #[derive(Debug, HashStable_Generic)]
 pub struct Item<'hir> {
     pub ident: Ident,
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
     pub kind: ItemKind<'hir>,
     pub span: Span,
     pub vis_span: Span,
@@ -2897,7 +2915,7 @@ impl Item<'_> {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 
     pub fn item_id(&self) -> ItemId {
@@ -2991,7 +3009,7 @@ pub enum ItemKind<'hir> {
     /// A MBE macro definition (`macro_rules!` or `macro`).
     Macro(ast::MacroDef, MacroKind),
     /// A module.
-    Mod(Mod<'hir>),
+    Mod(&'hir Mod<'hir>),
     /// An external module, e.g. `extern { .. }`.
     ForeignMod { abi: Abi, items: &'hir [ForeignItemRef] },
     /// Module-level inline assembly (from `global_asm!`).
@@ -3114,14 +3132,14 @@ pub enum AssocItemKind {
 // so it can fetched later.
 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct ForeignItemId {
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
 }
 
 impl ForeignItemId {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 }
 
@@ -3142,7 +3160,7 @@ pub struct ForeignItemRef {
 pub struct ForeignItem<'hir> {
     pub ident: Ident,
     pub kind: ForeignItemKind<'hir>,
-    pub def_id: LocalDefId,
+    pub def_id: OwnerId,
     pub span: Span,
     pub vis_span: Span,
 }
@@ -3151,7 +3169,7 @@ impl ForeignItem<'_> {
     #[inline]
     pub fn hir_id(&self) -> HirId {
         // Items are always HIR owners.
-        HirId::make_owner(self.def_id)
+        HirId::make_owner(self.def_id.def_id)
     }
 
     pub fn foreign_item_id(&self) -> ForeignItemId {
@@ -3245,7 +3263,7 @@ impl<'hir> OwnerNode<'hir> {
         Node::generics(self.into())
     }
 
-    pub fn def_id(self) -> LocalDefId {
+    pub fn def_id(self) -> OwnerId {
         match self {
             OwnerNode::Item(Item { def_id, .. })
             | OwnerNode::TraitItem(TraitItem { def_id, .. })
@@ -3495,16 +3513,32 @@ impl<'hir> Node<'hir> {
 mod size_asserts {
     use super::*;
     // These are in alphabetical order, which is easy to maintain.
-    static_assert_size!(Block<'static>, 48);
-    static_assert_size!(Expr<'static>, 56);
-    static_assert_size!(ForeignItem<'static>, 72);
+    static_assert_size!(Block<'_>, 48);
+    static_assert_size!(Body<'_>, 32);
+    static_assert_size!(Expr<'_>, 64);
+    static_assert_size!(ExprKind<'_>, 48);
+    static_assert_size!(FnDecl<'_>, 40);
+    static_assert_size!(ForeignItem<'_>, 72);
+    static_assert_size!(ForeignItemKind<'_>, 40);
+    static_assert_size!(GenericArg<'_>, 24);
     static_assert_size!(GenericBound<'_>, 48);
-    static_assert_size!(Generics<'static>, 56);
-    static_assert_size!(ImplItem<'static>, 88);
-    static_assert_size!(Impl<'static>, 80);
-    static_assert_size!(Item<'static>, 80);
-    static_assert_size!(Pat<'static>, 88);
-    static_assert_size!(QPath<'static>, 24);
-    static_assert_size!(TraitItem<'static>, 96);
-    static_assert_size!(Ty<'static>, 72);
+    static_assert_size!(Generics<'_>, 56);
+    static_assert_size!(Impl<'_>, 80);
+    static_assert_size!(ImplItem<'_>, 80);
+    static_assert_size!(ImplItemKind<'_>, 32);
+    static_assert_size!(Item<'_>, 80);
+    static_assert_size!(ItemKind<'_>, 48);
+    static_assert_size!(Local<'_>, 64);
+    static_assert_size!(Param<'_>, 32);
+    static_assert_size!(Pat<'_>, 72);
+    static_assert_size!(PatKind<'_>, 48);
+    static_assert_size!(Path<'_>, 48);
+    static_assert_size!(PathSegment<'_>, 56);
+    static_assert_size!(QPath<'_>, 24);
+    static_assert_size!(Stmt<'_>, 32);
+    static_assert_size!(StmtKind<'_>, 16);
+    static_assert_size!(TraitItem<'_>, 88);
+    static_assert_size!(TraitItemKind<'_>, 48);
+    static_assert_size!(Ty<'_>, 48);
+    static_assert_size!(TyKind<'_>, 32);
 }
diff --git a/compiler/rustc_hir/src/hir_id.rs b/compiler/rustc_hir/src/hir_id.rs
index 346ac9e96440..752f760ea971 100644
--- a/compiler/rustc_hir/src/hir_id.rs
+++ b/compiler/rustc_hir/src/hir_id.rs
@@ -1,6 +1,43 @@
-use crate::def_id::{LocalDefId, CRATE_DEF_ID};
+use crate::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
+use rustc_span::{def_id::DefPathHash, HashStableContext};
 use std::fmt;
 
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Encodable, Decodable)]
+pub struct OwnerId {
+    pub def_id: LocalDefId,
+}
+
+impl From<OwnerId> for HirId {
+    fn from(owner: OwnerId) -> HirId {
+        HirId { owner, local_id: ItemLocalId::from_u32(0) }
+    }
+}
+
+impl OwnerId {
+    #[inline]
+    pub fn to_def_id(self) -> DefId {
+        self.def_id.to_def_id()
+    }
+}
+
+impl<CTX: HashStableContext> HashStable<CTX> for OwnerId {
+    #[inline]
+    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+        self.to_stable_hash_key(hcx).hash_stable(hcx, hasher);
+    }
+}
+
+impl<CTX: HashStableContext> ToStableHashKey<CTX> for OwnerId {
+    type KeyType = DefPathHash;
+
+    #[inline]
+    fn to_stable_hash_key(&self, hcx: &CTX) -> DefPathHash {
+        hcx.def_path_hash(self.to_def_id())
+    }
+}
+
 /// Uniquely identifies a node in the HIR of the current crate. It is
 /// composed of the `owner`, which is the `LocalDefId` of the directly enclosing
 /// `hir::Item`, `hir::TraitItem`, or `hir::ImplItem` (i.e., the closest "item-like"),
@@ -15,19 +52,23 @@ use std::fmt;
 #[derive(Encodable, Decodable, HashStable_Generic)]
 #[rustc_pass_by_value]
 pub struct HirId {
-    pub owner: LocalDefId,
+    pub owner: OwnerId,
     pub local_id: ItemLocalId,
 }
 
 impl HirId {
+    /// Signal local id which should never be used.
+    pub const INVALID: HirId =
+        HirId { owner: OwnerId { def_id: CRATE_DEF_ID }, local_id: ItemLocalId::INVALID };
+
     #[inline]
-    pub fn expect_owner(self) -> LocalDefId {
+    pub fn expect_owner(self) -> OwnerId {
         assert_eq!(self.local_id.index(), 0);
         self.owner
     }
 
     #[inline]
-    pub fn as_owner(self) -> Option<LocalDefId> {
+    pub fn as_owner(self) -> Option<OwnerId> {
         if self.local_id.index() == 0 { Some(self.owner) } else { None }
     }
 
@@ -38,11 +79,14 @@ impl HirId {
 
     #[inline]
     pub fn make_owner(owner: LocalDefId) -> Self {
-        Self { owner, local_id: ItemLocalId::from_u32(0) }
+        Self { owner: OwnerId { def_id: owner }, local_id: ItemLocalId::from_u32(0) }
     }
 
     pub fn index(self) -> (usize, usize) {
-        (rustc_index::vec::Idx::index(self.owner), rustc_index::vec::Idx::index(self.local_id))
+        (
+            rustc_index::vec::Idx::index(self.owner.def_id),
+            rustc_index::vec::Idx::index(self.local_id),
+        )
     }
 }
 
@@ -64,8 +108,13 @@ impl PartialOrd for HirId {
     }
 }
 
-rustc_data_structures::define_id_collections!(HirIdMap, HirIdSet, HirId);
-rustc_data_structures::define_id_collections!(ItemLocalMap, ItemLocalSet, ItemLocalId);
+rustc_data_structures::define_stable_id_collections!(HirIdMap, HirIdSet, HirIdMapEntry, HirId);
+rustc_data_structures::define_id_collections!(
+    ItemLocalMap,
+    ItemLocalSet,
+    ItemLocalMapEntry,
+    ItemLocalId
+);
 
 rustc_index::newtype_index! {
     /// An `ItemLocalId` uniquely identifies something within a given "item-like";
@@ -86,4 +135,7 @@ impl ItemLocalId {
 }
 
 /// The `HirId` corresponding to `CRATE_NODE_ID` and `CRATE_DEF_ID`.
-pub const CRATE_HIR_ID: HirId = HirId { owner: CRATE_DEF_ID, local_id: ItemLocalId::from_u32(0) };
+pub const CRATE_HIR_ID: HirId =
+    HirId { owner: OwnerId { def_id: CRATE_DEF_ID }, local_id: ItemLocalId::from_u32(0) };
+
+pub const CRATE_OWNER_ID: OwnerId = OwnerId { def_id: CRATE_DEF_ID };
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 3d5e22add718..8f5f314ecae1 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -298,7 +298,7 @@ pub trait Visitor<'v>: Sized {
     fn visit_id(&mut self, _hir_id: HirId) {
         // Nothing to do.
     }
-    fn visit_name(&mut self, _span: Span, _name: Symbol) {
+    fn visit_name(&mut self, _name: Symbol) {
         // Nothing to do.
     }
     fn visit_ident(&mut self, ident: Ident) {
@@ -361,8 +361,8 @@ pub trait Visitor<'v>: Sized {
     fn visit_fn_decl(&mut self, fd: &'v FnDecl<'v>) {
         walk_fn_decl(self, fd)
     }
-    fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl<'v>, b: BodyId, s: Span, id: HirId) {
-        walk_fn(self, fk, fd, b, s, id)
+    fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl<'v>, b: BodyId, _: Span, id: HirId) {
+        walk_fn(self, fk, fd, b, id)
     }
     fn visit_use(&mut self, path: &'v Path<'v>, hir_id: HirId) {
         walk_use(self, path, hir_id)
@@ -388,8 +388,8 @@ pub trait Visitor<'v>: Sized {
     fn visit_param_bound(&mut self, bounds: &'v GenericBound<'v>) {
         walk_param_bound(self, bounds)
     }
-    fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef<'v>, m: TraitBoundModifier) {
-        walk_poly_trait_ref(self, t, m)
+    fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef<'v>) {
+        walk_poly_trait_ref(self, t)
     }
     fn visit_variant_data(&mut self, s: &'v VariantData<'v>) {
         walk_struct_def(self, s)
@@ -420,17 +420,18 @@ pub trait Visitor<'v>: Sized {
     fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
         walk_lifetime(self, lifetime)
     }
-    fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span) {
-        walk_qpath(self, qpath, id, span)
+    // The span is that of the surrounding type/pattern/expr/whatever.
+    fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, _span: Span) {
+        walk_qpath(self, qpath, id)
     }
     fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) {
         walk_path(self, path)
     }
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment<'v>) {
-        walk_path_segment(self, path_span, path_segment)
+    fn visit_path_segment(&mut self, path_segment: &'v PathSegment<'v>) {
+        walk_path_segment(self, path_segment)
     }
-    fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs<'v>) {
-        walk_generic_args(self, path_span, generic_args)
+    fn visit_generic_args(&mut self, generic_args: &'v GenericArgs<'v>) {
+        walk_generic_args(self, generic_args)
     }
     fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>) {
         walk_assoc_type_binding(self, type_binding)
@@ -472,7 +473,7 @@ pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) {
 }
 
 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
-    visitor.visit_name(ident.span, ident.name);
+    visitor.visit_name(ident.name);
 }
 
 pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
@@ -494,11 +495,7 @@ pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime
     }
 }
 
-pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    trait_ref: &'v PolyTraitRef<'v>,
-    _modifier: TraitBoundModifier,
-) {
+pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v PolyTraitRef<'v>) {
     walk_list!(visitor, visit_generic_param, trait_ref.bound_generic_params);
     visitor.visit_trait_ref(&trait_ref.trait_ref);
 }
@@ -519,7 +516,7 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
         ItemKind::ExternCrate(orig_name) => {
             visitor.visit_id(item.hir_id());
             if let Some(orig_name) = orig_name {
-                visitor.visit_name(item.span, orig_name);
+                visitor.visit_name(orig_name);
             }
         }
         ItemKind::Use(ref path, _) => {
@@ -670,7 +667,7 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
         TyKind::Path(ref qpath) => {
             visitor.visit_qpath(qpath, typ.hir_id, typ.span);
         }
-        TyKind::OpaqueDef(item_id, lifetimes) => {
+        TyKind::OpaqueDef(item_id, lifetimes, _in_trait) => {
             visitor.visit_nested_item(item_id);
             walk_list!(visitor, visit_generic_arg, lifetimes);
         }
@@ -680,7 +677,7 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
         }
         TyKind::TraitObject(bounds, ref lifetime, _syntax) => {
             for bound in bounds {
-                visitor.visit_poly_trait_ref(bound, TraitBoundModifier::None);
+                visitor.visit_poly_trait_ref(bound);
             }
             visitor.visit_lifetime(lifetime);
         }
@@ -693,12 +690,7 @@ pub fn walk_inf<'v, V: Visitor<'v>>(visitor: &mut V, inf: &'v InferArg) {
     visitor.visit_id(inf.hir_id);
 }
 
-pub fn walk_qpath<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    qpath: &'v QPath<'v>,
-    id: HirId,
-    span: Span,
-) {
+pub fn walk_qpath<'v, V: Visitor<'v>>(visitor: &mut V, qpath: &'v QPath<'v>, id: HirId) {
     match *qpath {
         QPath::Resolved(ref maybe_qself, ref path) => {
             walk_list!(visitor, visit_ty, maybe_qself);
@@ -706,7 +698,7 @@ pub fn walk_qpath<'v, V: Visitor<'v>>(
         }
         QPath::TypeRelative(ref qself, ref segment) => {
             visitor.visit_ty(qself);
-            visitor.visit_path_segment(span, segment);
+            visitor.visit_path_segment(segment);
         }
         QPath::LangItem(..) => {}
     }
@@ -714,27 +706,19 @@ pub fn walk_qpath<'v, V: Visitor<'v>>(
 
 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>) {
     for segment in path.segments {
-        visitor.visit_path_segment(path.span, segment);
+        visitor.visit_path_segment(segment);
     }
 }
 
-pub fn walk_path_segment<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    path_span: Span,
-    segment: &'v PathSegment<'v>,
-) {
+pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V, segment: &'v PathSegment<'v>) {
     visitor.visit_ident(segment.ident);
-    walk_list!(visitor, visit_id, segment.hir_id);
+    visitor.visit_id(segment.hir_id);
     if let Some(ref args) = segment.args {
-        visitor.visit_generic_args(path_span, args);
+        visitor.visit_generic_args(args);
     }
 }
 
-pub fn walk_generic_args<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    _path_span: Span,
-    generic_args: &'v GenericArgs<'v>,
-) {
+pub fn walk_generic_args<'v, V: Visitor<'v>>(visitor: &mut V, generic_args: &'v GenericArgs<'v>) {
     walk_list!(visitor, visit_generic_arg, generic_args.args);
     walk_list!(visitor, visit_assoc_type_binding, generic_args.bindings);
 }
@@ -745,7 +729,7 @@ pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(
 ) {
     visitor.visit_id(type_binding.hir_id);
     visitor.visit_ident(type_binding.ident);
-    visitor.visit_generic_args(type_binding.span, type_binding.gen_args);
+    visitor.visit_generic_args(type_binding.gen_args);
     match type_binding.kind {
         TypeBindingKind::Equality { ref term } => match term {
             Term::Ty(ref ty) => visitor.visit_ty(ty),
@@ -819,12 +803,12 @@ pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v
 
 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound<'v>) {
     match *bound {
-        GenericBound::Trait(ref typ, modifier) => {
-            visitor.visit_poly_trait_ref(typ, modifier);
+        GenericBound::Trait(ref typ, _modifier) => {
+            visitor.visit_poly_trait_ref(typ);
         }
-        GenericBound::LangItemTrait(_, span, hir_id, args) => {
+        GenericBound::LangItemTrait(_, _span, hir_id, args) => {
             visitor.visit_id(hir_id);
-            visitor.visit_generic_args(span, args);
+            visitor.visit_generic_args(args);
         }
         GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
     }
@@ -910,7 +894,6 @@ pub fn walk_fn<'v, V: Visitor<'v>>(
     function_kind: FnKind<'v>,
     function_declaration: &'v FnDecl<'v>,
     body_id: BodyId,
-    _span: Span,
     id: HirId,
 ) {
     visitor.visit_id(id);
@@ -1094,8 +1077,9 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
             visitor.visit_expr(callee_expression);
             walk_list!(visitor, visit_expr, arguments);
         }
-        ExprKind::MethodCall(ref segment, arguments, _) => {
-            visitor.visit_path_segment(expression.span, segment);
+        ExprKind::MethodCall(ref segment, receiver, arguments, _) => {
+            visitor.visit_path_segment(segment);
+            visitor.visit_expr(receiver);
             walk_list!(visitor, visit_expr, arguments);
         }
         ExprKind::Binary(_, ref left_expression, ref right_expression) => {
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index 0c01326d0032..ca615a4912a1 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -193,7 +193,8 @@ language_item_table! {
     DispatchFromDyn,         sym::dispatch_from_dyn,   dispatch_from_dyn_trait,    Target::Trait,          GenericRequirement::Minimum(1);
 
     // language items relating to transmutability
-    TransmuteTrait,          sym::transmute_trait,     transmute_trait,            Target::Trait,          GenericRequirement::Exact(6);
+    TransmuteOpts,           sym::transmute_opts,      transmute_opts,             Target::Struct,         GenericRequirement::Exact(0);
+    TransmuteTrait,          sym::transmute_trait,     transmute_trait,            Target::Trait,          GenericRequirement::Exact(3);
 
     Add(Op),                 sym::add,                 add_trait,                  Target::Trait,          GenericRequirement::Exact(1);
     Sub(Op),                 sym::sub,                 sub_trait,                  Target::Trait,          GenericRequirement::Exact(1);
@@ -237,7 +238,6 @@ language_item_table! {
     Future,                  sym::future_trait,        future_trait,               Target::Trait,          GenericRequirement::Exact(0);
     GeneratorState,          sym::generator_state,     gen_state,                  Target::Enum,           GenericRequirement::None;
     Generator,               sym::generator,           gen_trait,                  Target::Trait,          GenericRequirement::Minimum(1);
-    GeneratorReturn,         sym::generator_return,    generator_return,           Target::AssocTy,        GenericRequirement::None;
     Unpin,                   sym::unpin,               unpin_trait,                Target::Trait,          GenericRequirement::None;
     Pin,                     sym::pin,                 pin_type,                   Target::Struct,         GenericRequirement::None;
 
@@ -268,8 +268,6 @@ language_item_table! {
     DropInPlace,             sym::drop_in_place,       drop_in_place_fn,           Target::Fn,             GenericRequirement::Minimum(1);
     Oom,                     sym::oom,                 oom,                        Target::Fn,             GenericRequirement::None;
     AllocLayout,             sym::alloc_layout,        alloc_layout,               Target::Struct,         GenericRequirement::None;
-    ConstEvalSelect,         sym::const_eval_select,   const_eval_select,          Target::Fn,             GenericRequirement::Exact(4);
-    ConstConstEvalSelect,    sym::const_eval_select_ct,const_eval_select_ct,       Target::Fn,             GenericRequirement::Exact(4);
 
     Start,                   sym::start,               start_fn,                   Target::Fn,             GenericRequirement::Exact(1);
 
@@ -291,6 +289,8 @@ language_item_table! {
 
     Try,                     sym::Try,                 try_trait,                  Target::Trait,          GenericRequirement::None;
 
+    Tuple,                   sym::tuple_trait,         tuple_trait,                Target::Trait,          GenericRequirement::Exact(0);
+
     SliceLen,                sym::slice_len_fn,        slice_len_fn,               Target::Method(MethodKind::Inherent), GenericRequirement::None;
 
     // Language items from AST lowering
diff --git a/compiler/rustc_hir/src/lib.rs b/compiler/rustc_hir/src/lib.rs
index 092029ef09ec..1c4aa420c9bf 100644
--- a/compiler/rustc_hir/src/lib.rs
+++ b/compiler/rustc_hir/src/lib.rs
@@ -4,8 +4,7 @@
 
 #![feature(associated_type_defaults)]
 #![feature(closure_track_caller)]
-#![feature(const_btree_new)]
-#![feature(let_else)]
+#![feature(const_btree_len)]
 #![feature(once_cell)]
 #![feature(min_specialization)]
 #![feature(never_type)]
@@ -17,6 +16,9 @@
 #[macro_use]
 extern crate rustc_macros;
 
+#[macro_use]
+extern crate tracing;
+
 #[macro_use]
 extern crate rustc_data_structures;
 
diff --git a/compiler/rustc_hir/src/pat_util.rs b/compiler/rustc_hir/src/pat_util.rs
index 93112199b603..0c1819bb0c74 100644
--- a/compiler/rustc_hir/src/pat_util.rs
+++ b/compiler/rustc_hir/src/pat_util.rs
@@ -1,6 +1,6 @@
 use crate::def::{CtorOf, DefKind, Res};
 use crate::def_id::DefId;
-use crate::hir::{self, HirId, PatKind};
+use crate::hir::{self, BindingAnnotation, ByRef, HirId, PatKind};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::symbol::Ident;
@@ -35,7 +35,7 @@ pub trait EnumerateAndAdjustIterator {
     fn enumerate_and_adjust(
         self,
         expected_len: usize,
-        gap_pos: Option<usize>,
+        gap_pos: hir::DotDotPos,
     ) -> EnumerateAndAdjust<Self>
     where
         Self: Sized;
@@ -45,7 +45,7 @@ impl<T: ExactSizeIterator> EnumerateAndAdjustIterator for T {
     fn enumerate_and_adjust(
         self,
         expected_len: usize,
-        gap_pos: Option<usize>,
+        gap_pos: hir::DotDotPos,
     ) -> EnumerateAndAdjust<Self>
     where
         Self: Sized,
@@ -53,7 +53,7 @@ impl<T: ExactSizeIterator> EnumerateAndAdjustIterator for T {
         let actual_len = self.len();
         EnumerateAndAdjust {
             enumerate: self.enumerate(),
-            gap_pos: gap_pos.unwrap_or(expected_len),
+            gap_pos: gap_pos.as_opt_usize().unwrap_or(expected_len),
             gap_len: expected_len - actual_len,
         }
     }
@@ -93,12 +93,7 @@ impl hir::Pat<'_> {
 
     pub fn simple_ident(&self) -> Option<Ident> {
         match self.kind {
-            PatKind::Binding(
-                hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Mutable,
-                _,
-                ident,
-                None,
-            ) => Some(ident),
+            PatKind::Binding(BindingAnnotation(ByRef::No, _), _, ident, None) => Some(ident),
             _ => None,
         }
     }
@@ -135,11 +130,11 @@ impl hir::Pat<'_> {
     pub fn contains_explicit_ref_binding(&self) -> Option<hir::Mutability> {
         let mut result = None;
         self.each_binding(|annotation, _, _, _| match annotation {
-            hir::BindingAnnotation::Ref => match result {
+            hir::BindingAnnotation::REF => match result {
                 None | Some(hir::Mutability::Not) => result = Some(hir::Mutability::Not),
                 _ => {}
             },
-            hir::BindingAnnotation::RefMut => result = Some(hir::Mutability::Mut),
+            hir::BindingAnnotation::REF_MUT => result = Some(hir::Mutability::Mut),
             _ => {}
         });
         result
diff --git a/compiler/rustc_hir/src/stable_hash_impls.rs b/compiler/rustc_hir/src/stable_hash_impls.rs
index 5b9c42686c34..06b7a65662e7 100644
--- a/compiler/rustc_hir/src/stable_hash_impls.rs
+++ b/compiler/rustc_hir/src/stable_hash_impls.rs
@@ -20,7 +20,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for HirId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
-        let def_path_hash = self.owner.to_stable_hash_key(hcx);
+        let def_path_hash = self.owner.def_id.to_stable_hash_key(hcx);
         (def_path_hash, self.local_id)
     }
 }
@@ -49,7 +49,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        self.def_id.to_stable_hash_key(hcx)
+        self.def_id.def_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -58,7 +58,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for TraitItemId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        self.def_id.to_stable_hash_key(hcx)
+        self.def_id.def_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -67,7 +67,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ImplItemId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        self.def_id.to_stable_hash_key(hcx)
+        self.def_id.def_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -76,7 +76,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ForeignItemId
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        self.def_id.to_stable_hash_key(hcx)
+        self.def_id.def_id.to_stable_hash_key(hcx)
     }
 }
 
diff --git a/compiler/rustc_hir/src/target.rs b/compiler/rustc_hir/src/target.rs
index 78bfd7191dba..5917d5e346e3 100644
--- a/compiler/rustc_hir/src/target.rs
+++ b/compiler/rustc_hir/src/target.rs
@@ -36,6 +36,7 @@ pub enum Target {
     GlobalAsm,
     TyAlias,
     OpaqueTy,
+    ImplTraitPlaceholder,
     Enum,
     Variant,
     Struct,
@@ -79,7 +80,13 @@ impl Target {
             ItemKind::ForeignMod { .. } => Target::ForeignMod,
             ItemKind::GlobalAsm(..) => Target::GlobalAsm,
             ItemKind::TyAlias(..) => Target::TyAlias,
-            ItemKind::OpaqueTy(..) => Target::OpaqueTy,
+            ItemKind::OpaqueTy(ref opaque) => {
+                if opaque.in_trait {
+                    Target::ImplTraitPlaceholder
+                } else {
+                    Target::OpaqueTy
+                }
+            }
             ItemKind::Enum(..) => Target::Enum,
             ItemKind::Struct(..) => Target::Struct,
             ItemKind::Union(..) => Target::Union,
@@ -103,6 +110,7 @@ impl Target {
             DefKind::GlobalAsm => Target::GlobalAsm,
             DefKind::TyAlias => Target::TyAlias,
             DefKind::OpaqueTy => Target::OpaqueTy,
+            DefKind::ImplTraitPlaceholder => Target::ImplTraitPlaceholder,
             DefKind::Enum => Target::Enum,
             DefKind::Struct => Target::Struct,
             DefKind::Union => Target::Union,
@@ -157,6 +165,7 @@ impl Target {
             Target::GlobalAsm => "global asm",
             Target::TyAlias => "type alias",
             Target::OpaqueTy => "opaque type",
+            Target::ImplTraitPlaceholder => "opaque type in trait",
             Target::Enum => "enum",
             Target::Variant => "enum variant",
             Target::Struct => "struct",
diff --git a/compiler/rustc_hir/src/weak_lang_items.rs b/compiler/rustc_hir/src/weak_lang_items.rs
index b6a85c0472e0..da9c9c1216e9 100644
--- a/compiler/rustc_hir/src/weak_lang_items.rs
+++ b/compiler/rustc_hir/src/weak_lang_items.rs
@@ -18,6 +18,12 @@ pub static WEAK_ITEMS_REFS: LazyLock<FxIndexMap<Symbol, LangItem>> = LazyLock::n
     map
 });
 
+pub static WEAK_ITEMS_SYMBOLS: LazyLock<FxIndexMap<LangItem, Symbol>> = LazyLock::new(|| {
+    let mut map = FxIndexMap::default();
+    $(map.insert(LangItem::$item, sym::$sym);)*
+    map
+});
+
 pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol>
 {
     lang_items::extract(attrs).and_then(|(name, _)| {
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 42663da8a3f9..35a58296e370 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -9,7 +9,9 @@ use rustc_ast_pretty::pp::{self, Breaks};
 use rustc_ast_pretty::pprust::{Comments, PrintState};
 use rustc_hir as hir;
 use rustc_hir::LifetimeParamKind;
-use rustc_hir::{GenericArg, GenericParam, GenericParamKind, Node, Term};
+use rustc_hir::{
+    BindingAnnotation, ByRef, GenericArg, GenericParam, GenericParamKind, Mutability, Node, Term,
+};
 use rustc_hir::{GenericBound, PatKind, RangeEnd, TraitBoundModifier};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, Ident, IdentPrinter, Symbol};
@@ -1181,15 +1183,20 @@ impl<'a> State<'a> {
         self.print_call_post(args)
     }
 
-    fn print_expr_method_call(&mut self, segment: &hir::PathSegment<'_>, args: &[hir::Expr<'_>]) {
-        let base_args = &args[1..];
-        self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX);
+    fn print_expr_method_call(
+        &mut self,
+        segment: &hir::PathSegment<'_>,
+        receiver: &hir::Expr<'_>,
+        args: &[hir::Expr<'_>],
+    ) {
+        let base_args = args;
+        self.print_expr_maybe_paren(&receiver, parser::PREC_POSTFIX);
         self.word(".");
         self.print_ident(segment.ident);
 
         let generic_args = segment.args();
         if !generic_args.args.is_empty() || !generic_args.bindings.is_empty() {
-            self.print_generic_args(generic_args, segment.infer_args, true);
+            self.print_generic_args(generic_args, true);
         }
 
         self.print_call_post(base_args)
@@ -1394,8 +1401,8 @@ impl<'a> State<'a> {
             hir::ExprKind::Call(func, args) => {
                 self.print_expr_call(func, args);
             }
-            hir::ExprKind::MethodCall(segment, args, _) => {
-                self.print_expr_method_call(segment, args);
+            hir::ExprKind::MethodCall(segment, receiver, args, _) => {
+                self.print_expr_method_call(segment, receiver, args);
             }
             hir::ExprKind::Binary(op, lhs, rhs) => {
                 self.print_expr_binary(op, lhs, rhs);
@@ -1592,7 +1599,7 @@ impl<'a> State<'a> {
             }
             if segment.ident.name != kw::PathRoot {
                 self.print_ident(segment.ident);
-                self.print_generic_args(segment.args(), segment.infer_args, colons_before_params);
+                self.print_generic_args(segment.args(), colons_before_params);
             }
         }
     }
@@ -1600,7 +1607,7 @@ impl<'a> State<'a> {
     pub fn print_path_segment(&mut self, segment: &hir::PathSegment<'_>) {
         if segment.ident.name != kw::PathRoot {
             self.print_ident(segment.ident);
-            self.print_generic_args(segment.args(), segment.infer_args, false);
+            self.print_generic_args(segment.args(), false);
         }
     }
 
@@ -1619,11 +1626,7 @@ impl<'a> State<'a> {
                     }
                     if segment.ident.name != kw::PathRoot {
                         self.print_ident(segment.ident);
-                        self.print_generic_args(
-                            segment.args(),
-                            segment.infer_args,
-                            colons_before_params,
-                        );
+                        self.print_generic_args(segment.args(), colons_before_params);
                     }
                 }
 
@@ -1631,11 +1634,7 @@ impl<'a> State<'a> {
                 self.word("::");
                 let item_segment = path.segments.last().unwrap();
                 self.print_ident(item_segment.ident);
-                self.print_generic_args(
-                    item_segment.args(),
-                    item_segment.infer_args,
-                    colons_before_params,
-                )
+                self.print_generic_args(item_segment.args(), colons_before_params)
             }
             hir::QPath::TypeRelative(qself, item_segment) => {
                 // If we've got a compound-qualified-path, let's push an additional pair of angle
@@ -1651,11 +1650,7 @@ impl<'a> State<'a> {
 
                 self.word("::");
                 self.print_ident(item_segment.ident);
-                self.print_generic_args(
-                    item_segment.args(),
-                    item_segment.infer_args,
-                    colons_before_params,
-                )
+                self.print_generic_args(item_segment.args(), colons_before_params)
             }
             hir::QPath::LangItem(lang_item, span, _) => {
                 self.word("#[lang = \"");
@@ -1668,7 +1663,6 @@ impl<'a> State<'a> {
     fn print_generic_args(
         &mut self,
         generic_args: &hir::GenericArgs<'_>,
-        infer_args: bool,
         colons_before_params: bool,
     ) {
         if generic_args.parenthesized {
@@ -1715,13 +1709,6 @@ impl<'a> State<'a> {
                 );
             }
 
-            // FIXME(eddyb): this would leak into error messages (e.g.,
-            // "non-exhaustive patterns: `Some::<..>(_)` not covered").
-            if infer_args && false {
-                start_or_comma(self);
-                self.word("..");
-            }
-
             for binding in generic_args.bindings {
                 start_or_comma(self);
                 self.print_type_binding(binding);
@@ -1735,7 +1722,7 @@ impl<'a> State<'a> {
 
     pub fn print_type_binding(&mut self, binding: &hir::TypeBinding<'_>) {
         self.print_ident(binding.ident);
-        self.print_generic_args(binding.gen_args, false, false);
+        self.print_generic_args(binding.gen_args, false);
         self.space();
         match binding.kind {
             hir::TypeBindingKind::Equality { ref term } => {
@@ -1758,20 +1745,12 @@ impl<'a> State<'a> {
         // is that it doesn't matter
         match pat.kind {
             PatKind::Wild => self.word("_"),
-            PatKind::Binding(binding_mode, _, ident, sub) => {
-                match binding_mode {
-                    hir::BindingAnnotation::Ref => {
-                        self.word_nbsp("ref");
-                        self.print_mutability(hir::Mutability::Not, false);
-                    }
-                    hir::BindingAnnotation::RefMut => {
-                        self.word_nbsp("ref");
-                        self.print_mutability(hir::Mutability::Mut, false);
-                    }
-                    hir::BindingAnnotation::Unannotated => {}
-                    hir::BindingAnnotation::Mutable => {
-                        self.word_nbsp("mut");
-                    }
+            PatKind::Binding(BindingAnnotation(by_ref, mutbl), _, ident, sub) => {
+                if by_ref == ByRef::Yes {
+                    self.word_nbsp("ref");
+                }
+                if mutbl == Mutability::Mut {
+                    self.word_nbsp("mut");
                 }
                 self.print_ident(ident);
                 if let Some(p) = sub {
@@ -1782,7 +1761,8 @@ impl<'a> State<'a> {
             PatKind::TupleStruct(ref qpath, elts, ddpos) => {
                 self.print_qpath(qpath, true);
                 self.popen();
-                if let Some(ddpos) = ddpos {
+                if let Some(ddpos) = ddpos.as_opt_usize() {
+                    let ddpos = ddpos as usize;
                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p));
                     if ddpos != 0 {
                         self.word_space(",");
@@ -1825,7 +1805,7 @@ impl<'a> State<'a> {
             }
             PatKind::Tuple(elts, ddpos) => {
                 self.popen();
-                if let Some(ddpos) = ddpos {
+                if let Some(ddpos) = ddpos.as_opt_usize() {
                     self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p));
                     if ddpos != 0 {
                         self.word_space(",");
@@ -2413,9 +2393,9 @@ fn contains_exterior_struct_lit(value: &hir::Expr<'_>) -> bool {
             contains_exterior_struct_lit(x)
         }
 
-        hir::ExprKind::MethodCall(.., exprs, _) => {
+        hir::ExprKind::MethodCall(_, receiver, ..) => {
             // `X { y: 1 }.bar(...)`
-            contains_exterior_struct_lit(&exprs[0])
+            contains_exterior_struct_lit(receiver)
         }
 
         _ => false,
diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
index 1e88e8091c37..83dd9a67e61b 100644
--- a/compiler/rustc_incremental/src/lib.rs
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -2,7 +2,6 @@
 
 #![deny(missing_docs)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(let_else)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index 710c4a01b244..09163e4f25f3 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -149,19 +149,19 @@ pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
         let crate_items = tcx.hir_crate_items(());
 
         for id in crate_items.items() {
-            dirty_clean_visitor.check_item(id.def_id);
+            dirty_clean_visitor.check_item(id.def_id.def_id);
         }
 
         for id in crate_items.trait_items() {
-            dirty_clean_visitor.check_item(id.def_id);
+            dirty_clean_visitor.check_item(id.def_id.def_id);
         }
 
         for id in crate_items.impl_items() {
-            dirty_clean_visitor.check_item(id.def_id);
+            dirty_clean_visitor.check_item(id.def_id.def_id);
         }
 
         for id in crate_items.foreign_items() {
-            dirty_clean_visitor.check_item(id.def_id);
+            dirty_clean_visitor.check_item(id.def_id.def_id);
         }
 
         let mut all_attrs = FindAllAttrs { tcx, found_attrs: vec![] };
diff --git a/compiler/rustc_index/src/lib.rs b/compiler/rustc_index/src/lib.rs
index aa34673de81d..9753fb355308 100644
--- a/compiler/rustc_index/src/lib.rs
+++ b/compiler/rustc_index/src/lib.rs
@@ -3,7 +3,6 @@
 #![feature(allow_internal_unstable)]
 #![feature(bench_black_box)]
 #![feature(extend_one)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(new_uninit)]
 #![feature(step_trait)]
diff --git a/compiler/rustc_infer/src/errors.rs b/compiler/rustc_infer/src/errors.rs
deleted file mode 100644
index 938f8aa77a5b..000000000000
--- a/compiler/rustc_infer/src/errors.rs
+++ /dev/null
@@ -1,254 +0,0 @@
-use rustc_errors::{fluent, AddSubdiagnostic, DiagnosticMessage, DiagnosticStyledString};
-use rustc_hir::FnRetTy;
-use rustc_macros::SessionDiagnostic;
-use rustc_span::{BytePos, Span};
-
-use crate::infer::error_reporting::{
-    need_type_info::{GeneratorKindAsDiagArg, UnderspecifiedArgKind},
-    ObligationCauseAsDiagArg,
-};
-
-#[derive(SessionDiagnostic)]
-#[diag(infer::opaque_hidden_type)]
-pub struct OpaqueHiddenTypeDiag {
-    #[primary_span]
-    #[label]
-    pub span: Span,
-    #[note(infer::opaque_type)]
-    pub opaque_type: Span,
-    #[note(infer::hidden_type)]
-    pub hidden_type: Span,
-}
-
-#[derive(SessionDiagnostic)]
-#[diag(infer::type_annotations_needed, code = "E0282")]
-pub struct AnnotationRequired<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub source_kind: &'static str,
-    pub source_name: &'a str,
-    #[label]
-    pub failure_span: Option<Span>,
-    #[subdiagnostic]
-    pub bad_label: Option<InferenceBadError<'a>>,
-    #[subdiagnostic]
-    pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
-    #[subdiagnostic]
-    pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
-}
-
-// Copy of `AnnotationRequired` for E0283
-#[derive(SessionDiagnostic)]
-#[diag(infer::type_annotations_needed, code = "E0283")]
-pub struct AmbigousImpl<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub source_kind: &'static str,
-    pub source_name: &'a str,
-    #[label]
-    pub failure_span: Option<Span>,
-    #[subdiagnostic]
-    pub bad_label: Option<InferenceBadError<'a>>,
-    #[subdiagnostic]
-    pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
-    #[subdiagnostic]
-    pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
-}
-
-// Copy of `AnnotationRequired` for E0284
-#[derive(SessionDiagnostic)]
-#[diag(infer::type_annotations_needed, code = "E0284")]
-pub struct AmbigousReturn<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub source_kind: &'static str,
-    pub source_name: &'a str,
-    #[label]
-    pub failure_span: Option<Span>,
-    #[subdiagnostic]
-    pub bad_label: Option<InferenceBadError<'a>>,
-    #[subdiagnostic]
-    pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
-    #[subdiagnostic]
-    pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
-}
-
-#[derive(SessionDiagnostic)]
-#[diag(infer::need_type_info_in_generator, code = "E0698")]
-pub struct NeedTypeInfoInGenerator<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub generator_kind: GeneratorKindAsDiagArg,
-    #[subdiagnostic]
-    pub bad_label: InferenceBadError<'a>,
-}
-
-// Used when a better one isn't available
-#[derive(SessionSubdiagnostic)]
-#[label(infer::label_bad)]
-pub struct InferenceBadError<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub bad_kind: &'static str,
-    pub prefix_kind: UnderspecifiedArgKind,
-    pub has_parent: bool,
-    pub prefix: &'a str,
-    pub parent_prefix: &'a str,
-    pub parent_name: String,
-    pub name: String,
-}
-
-#[derive(SessionSubdiagnostic)]
-pub enum SourceKindSubdiag<'a> {
-    #[suggestion_verbose(
-        infer::source_kind_subdiag_let,
-        code = ": {type_name}",
-        applicability = "has-placeholders"
-    )]
-    LetLike {
-        #[primary_span]
-        span: Span,
-        name: String,
-        type_name: String,
-        kind: &'static str,
-        x_kind: &'static str,
-        prefix_kind: UnderspecifiedArgKind,
-        prefix: &'a str,
-        arg_name: String,
-    },
-    #[label(infer::source_kind_subdiag_generic_label)]
-    GenericLabel {
-        #[primary_span]
-        span: Span,
-        is_type: bool,
-        param_name: String,
-        parent_exists: bool,
-        parent_prefix: String,
-        parent_name: String,
-    },
-    #[suggestion_verbose(
-        infer::source_kind_subdiag_generic_suggestion,
-        code = "::<{args}>",
-        applicability = "has-placeholders"
-    )]
-    GenericSuggestion {
-        #[primary_span]
-        span: Span,
-        arg_count: usize,
-        args: String,
-    },
-}
-
-// Has to be implemented manually because multipart suggestions are not supported by the derive macro.
-// Would be a part of `SourceKindSubdiag` otherwise.
-pub enum SourceKindMultiSuggestion<'a> {
-    FullyQualified {
-        span: Span,
-        def_path: String,
-        adjustment: &'a str,
-        successor: (&'a str, BytePos),
-    },
-    ClosureReturn {
-        ty_info: String,
-        data: &'a FnRetTy<'a>,
-        should_wrap_expr: Option<Span>,
-    },
-}
-
-impl AddSubdiagnostic for SourceKindMultiSuggestion<'_> {
-    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
-        match self {
-            Self::FullyQualified { span, def_path, adjustment, successor } => {
-                let suggestion = vec![
-                    (span.shrink_to_lo(), format!("{def_path}({adjustment}")),
-                    (span.shrink_to_hi().with_hi(successor.1), successor.0.to_string()),
-                ];
-                diag.multipart_suggestion_verbose(
-                    fluent::infer::source_kind_fully_qualified,
-                    suggestion,
-                    rustc_errors::Applicability::HasPlaceholders,
-                );
-            }
-            Self::ClosureReturn { ty_info, data, should_wrap_expr } => {
-                let (arrow, post) = match data {
-                    FnRetTy::DefaultReturn(_) => ("-> ", " "),
-                    _ => ("", ""),
-                };
-                let suggestion = match should_wrap_expr {
-                    Some(end_span) => vec![
-                        (data.span(), format!("{}{}{}{{ ", arrow, ty_info, post)),
-                        (end_span, " }".to_string()),
-                    ],
-                    None => vec![(data.span(), format!("{}{}{}", arrow, ty_info, post))],
-                };
-                diag.multipart_suggestion_verbose(
-                    fluent::infer::source_kind_closure_return,
-                    suggestion,
-                    rustc_errors::Applicability::HasPlaceholders,
-                );
-            }
-        }
-    }
-}
-
-pub enum RegionOriginNote<'a> {
-    Plain {
-        span: Span,
-        msg: DiagnosticMessage,
-    },
-    WithName {
-        span: Span,
-        msg: DiagnosticMessage,
-        name: &'a str,
-        continues: bool,
-    },
-    WithRequirement {
-        span: Span,
-        requirement: ObligationCauseAsDiagArg<'a>,
-        expected_found: Option<(DiagnosticStyledString, DiagnosticStyledString)>,
-    },
-}
-
-impl AddSubdiagnostic for RegionOriginNote<'_> {
-    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
-        let mut label_or_note = |span, msg: DiagnosticMessage| {
-            let sub_count = diag.children.iter().filter(|d| d.span.is_dummy()).count();
-            let expanded_sub_count = diag.children.iter().filter(|d| !d.span.is_dummy()).count();
-            let span_is_primary = diag.span.primary_spans().iter().all(|&sp| sp == span);
-            if span_is_primary && sub_count == 0 && expanded_sub_count == 0 {
-                diag.span_label(span, msg);
-            } else if span_is_primary && expanded_sub_count == 0 {
-                diag.note(msg);
-            } else {
-                diag.span_note(span, msg);
-            }
-        };
-        match self {
-            RegionOriginNote::Plain { span, msg } => {
-                label_or_note(span, msg);
-            }
-            RegionOriginNote::WithName { span, msg, name, continues } => {
-                label_or_note(span, msg);
-                diag.set_arg("name", name);
-                diag.set_arg("continues", continues);
-            }
-            RegionOriginNote::WithRequirement {
-                span,
-                requirement,
-                expected_found: Some((expected, found)),
-            } => {
-                label_or_note(span, fluent::infer::subtype);
-                diag.set_arg("requirement", requirement);
-
-                diag.note_expected_found(&"", expected, &"", found);
-            }
-            RegionOriginNote::WithRequirement { span, requirement, expected_found: None } => {
-                // FIXME: this really should be handled at some earlier stage. Our
-                // handling of region checking when type errors are present is
-                // *terrible*.
-                label_or_note(span, fluent::infer::subtype_2);
-                diag.set_arg("requirement", requirement);
-            }
-        };
-    }
-}
diff --git a/compiler/rustc_infer/src/errors/mod.rs b/compiler/rustc_infer/src/errors/mod.rs
new file mode 100644
index 000000000000..85b877652c6a
--- /dev/null
+++ b/compiler/rustc_infer/src/errors/mod.rs
@@ -0,0 +1,499 @@
+use hir::GenericParamKind;
+use rustc_errors::{
+    fluent, AddToDiagnostic, Applicability, DiagnosticMessage, DiagnosticStyledString, MultiSpan,
+};
+use rustc_hir as hir;
+use rustc_hir::{FnRetTy, Ty};
+use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_middle::ty::{Region, TyCtxt};
+use rustc_span::symbol::kw;
+use rustc_span::{symbol::Ident, BytePos, Span};
+
+use crate::infer::error_reporting::{
+    need_type_info::{GeneratorKindAsDiagArg, UnderspecifiedArgKind},
+    ObligationCauseAsDiagArg,
+};
+
+pub mod note_and_explain;
+
+#[derive(Diagnostic)]
+#[diag(infer::opaque_hidden_type)]
+pub struct OpaqueHiddenTypeDiag {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[note(infer::opaque_type)]
+    pub opaque_type: Span,
+    #[note(infer::hidden_type)]
+    pub hidden_type: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(infer::type_annotations_needed, code = "E0282")]
+pub struct AnnotationRequired<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub source_kind: &'static str,
+    pub source_name: &'a str,
+    #[label]
+    pub failure_span: Option<Span>,
+    #[subdiagnostic]
+    pub bad_label: Option<InferenceBadError<'a>>,
+    #[subdiagnostic]
+    pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
+    #[subdiagnostic]
+    pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
+}
+
+// Copy of `AnnotationRequired` for E0283
+#[derive(Diagnostic)]
+#[diag(infer::type_annotations_needed, code = "E0283")]
+pub struct AmbigousImpl<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub source_kind: &'static str,
+    pub source_name: &'a str,
+    #[label]
+    pub failure_span: Option<Span>,
+    #[subdiagnostic]
+    pub bad_label: Option<InferenceBadError<'a>>,
+    #[subdiagnostic]
+    pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
+    #[subdiagnostic]
+    pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
+}
+
+// Copy of `AnnotationRequired` for E0284
+#[derive(Diagnostic)]
+#[diag(infer::type_annotations_needed, code = "E0284")]
+pub struct AmbigousReturn<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub source_kind: &'static str,
+    pub source_name: &'a str,
+    #[label]
+    pub failure_span: Option<Span>,
+    #[subdiagnostic]
+    pub bad_label: Option<InferenceBadError<'a>>,
+    #[subdiagnostic]
+    pub infer_subdiags: Vec<SourceKindSubdiag<'a>>,
+    #[subdiagnostic]
+    pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
+}
+
+#[derive(Diagnostic)]
+#[diag(infer::need_type_info_in_generator, code = "E0698")]
+pub struct NeedTypeInfoInGenerator<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub generator_kind: GeneratorKindAsDiagArg,
+    #[subdiagnostic]
+    pub bad_label: InferenceBadError<'a>,
+}
+
+// Used when a better one isn't available
+#[derive(Subdiagnostic)]
+#[label(infer::label_bad)]
+pub struct InferenceBadError<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub bad_kind: &'static str,
+    pub prefix_kind: UnderspecifiedArgKind,
+    pub has_parent: bool,
+    pub prefix: &'a str,
+    pub parent_prefix: &'a str,
+    pub parent_name: String,
+    pub name: String,
+}
+
+#[derive(Subdiagnostic)]
+pub enum SourceKindSubdiag<'a> {
+    #[suggestion_verbose(
+        infer::source_kind_subdiag_let,
+        code = ": {type_name}",
+        applicability = "has-placeholders"
+    )]
+    LetLike {
+        #[primary_span]
+        span: Span,
+        name: String,
+        type_name: String,
+        kind: &'static str,
+        x_kind: &'static str,
+        prefix_kind: UnderspecifiedArgKind,
+        prefix: &'a str,
+        arg_name: String,
+    },
+    #[label(infer::source_kind_subdiag_generic_label)]
+    GenericLabel {
+        #[primary_span]
+        span: Span,
+        is_type: bool,
+        param_name: String,
+        parent_exists: bool,
+        parent_prefix: String,
+        parent_name: String,
+    },
+    #[suggestion_verbose(
+        infer::source_kind_subdiag_generic_suggestion,
+        code = "::<{args}>",
+        applicability = "has-placeholders"
+    )]
+    GenericSuggestion {
+        #[primary_span]
+        span: Span,
+        arg_count: usize,
+        args: String,
+    },
+}
+
+#[derive(Subdiagnostic)]
+pub enum SourceKindMultiSuggestion<'a> {
+    #[multipart_suggestion_verbose(
+        infer::source_kind_fully_qualified,
+        applicability = "has-placeholders"
+    )]
+    FullyQualified {
+        #[suggestion_part(code = "{def_path}({adjustment}")]
+        span_lo: Span,
+        #[suggestion_part(code = "{successor_pos}")]
+        span_hi: Span,
+        def_path: String,
+        adjustment: &'a str,
+        successor_pos: &'a str,
+    },
+    #[multipart_suggestion_verbose(
+        infer::source_kind_closure_return,
+        applicability = "has-placeholders"
+    )]
+    ClosureReturn {
+        #[suggestion_part(code = "{start_span_code}")]
+        start_span: Span,
+        start_span_code: String,
+        #[suggestion_part(code = " }}")]
+        end_span: Option<Span>,
+    },
+}
+
+impl<'a> SourceKindMultiSuggestion<'a> {
+    pub fn new_fully_qualified(
+        span: Span,
+        def_path: String,
+        adjustment: &'a str,
+        successor: (&'a str, BytePos),
+    ) -> Self {
+        Self::FullyQualified {
+            span_lo: span.shrink_to_lo(),
+            span_hi: span.shrink_to_hi().with_hi(successor.1),
+            def_path,
+            adjustment,
+            successor_pos: successor.0,
+        }
+    }
+
+    pub fn new_closure_return(
+        ty_info: String,
+        data: &'a FnRetTy<'a>,
+        should_wrap_expr: Option<Span>,
+    ) -> Self {
+        let (arrow, post) = match data {
+            FnRetTy::DefaultReturn(_) => ("-> ", " "),
+            _ => ("", ""),
+        };
+        let (start_span, start_span_code, end_span) = match should_wrap_expr {
+            Some(end_span) => {
+                (data.span(), format!("{}{}{}{{ ", arrow, ty_info, post), Some(end_span))
+            }
+            None => (data.span(), format!("{}{}{}", arrow, ty_info, post), None),
+        };
+        Self::ClosureReturn { start_span, start_span_code, end_span }
+    }
+}
+
+pub enum RegionOriginNote<'a> {
+    Plain {
+        span: Span,
+        msg: DiagnosticMessage,
+    },
+    WithName {
+        span: Span,
+        msg: DiagnosticMessage,
+        name: &'a str,
+        continues: bool,
+    },
+    WithRequirement {
+        span: Span,
+        requirement: ObligationCauseAsDiagArg<'a>,
+        expected_found: Option<(DiagnosticStyledString, DiagnosticStyledString)>,
+    },
+}
+
+impl AddToDiagnostic for RegionOriginNote<'_> {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        let mut label_or_note = |span, msg: DiagnosticMessage| {
+            let sub_count = diag.children.iter().filter(|d| d.span.is_dummy()).count();
+            let expanded_sub_count = diag.children.iter().filter(|d| !d.span.is_dummy()).count();
+            let span_is_primary = diag.span.primary_spans().iter().all(|&sp| sp == span);
+            if span_is_primary && sub_count == 0 && expanded_sub_count == 0 {
+                diag.span_label(span, msg);
+            } else if span_is_primary && expanded_sub_count == 0 {
+                diag.note(msg);
+            } else {
+                diag.span_note(span, msg);
+            }
+        };
+        match self {
+            RegionOriginNote::Plain { span, msg } => {
+                label_or_note(span, msg);
+            }
+            RegionOriginNote::WithName { span, msg, name, continues } => {
+                label_or_note(span, msg);
+                diag.set_arg("name", name);
+                diag.set_arg("continues", continues);
+            }
+            RegionOriginNote::WithRequirement {
+                span,
+                requirement,
+                expected_found: Some((expected, found)),
+            } => {
+                label_or_note(span, fluent::infer::subtype);
+                diag.set_arg("requirement", requirement);
+
+                diag.note_expected_found(&"", expected, &"", found);
+            }
+            RegionOriginNote::WithRequirement { span, requirement, expected_found: None } => {
+                // FIXME: this really should be handled at some earlier stage. Our
+                // handling of region checking when type errors are present is
+                // *terrible*.
+                label_or_note(span, fluent::infer::subtype_2);
+                diag.set_arg("requirement", requirement);
+            }
+        };
+    }
+}
+
+pub enum LifetimeMismatchLabels {
+    InRet {
+        param_span: Span,
+        ret_span: Span,
+        span: Span,
+        label_var1: Option<Ident>,
+    },
+    Normal {
+        hir_equal: bool,
+        ty_sup: Span,
+        ty_sub: Span,
+        span: Span,
+        sup: Option<Ident>,
+        sub: Option<Ident>,
+    },
+}
+
+impl AddToDiagnostic for LifetimeMismatchLabels {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        match self {
+            LifetimeMismatchLabels::InRet { param_span, ret_span, span, label_var1 } => {
+                diag.span_label(param_span, fluent::infer::declared_different);
+                diag.span_label(ret_span, fluent::infer::nothing);
+                diag.span_label(span, fluent::infer::data_returned);
+                diag.set_arg("label_var1_exists", label_var1.is_some());
+                diag.set_arg("label_var1", label_var1.map(|x| x.to_string()).unwrap_or_default());
+            }
+            LifetimeMismatchLabels::Normal {
+                hir_equal,
+                ty_sup,
+                ty_sub,
+                span,
+                sup: label_var1,
+                sub: label_var2,
+            } => {
+                if hir_equal {
+                    diag.span_label(ty_sup, fluent::infer::declared_multiple);
+                    diag.span_label(ty_sub, fluent::infer::nothing);
+                    diag.span_label(span, fluent::infer::data_lifetime_flow);
+                } else {
+                    diag.span_label(ty_sup, fluent::infer::types_declared_different);
+                    diag.span_label(ty_sub, fluent::infer::nothing);
+                    diag.span_label(span, fluent::infer::data_flows);
+                    diag.set_arg("label_var1_exists", label_var1.is_some());
+                    diag.set_arg(
+                        "label_var1",
+                        label_var1.map(|x| x.to_string()).unwrap_or_default(),
+                    );
+                    diag.set_arg("label_var2_exists", label_var2.is_some());
+                    diag.set_arg(
+                        "label_var2",
+                        label_var2.map(|x| x.to_string()).unwrap_or_default(),
+                    );
+                }
+            }
+        }
+    }
+}
+
+pub struct AddLifetimeParamsSuggestion<'a> {
+    pub tcx: TyCtxt<'a>,
+    pub sub: Region<'a>,
+    pub ty_sup: &'a Ty<'a>,
+    pub ty_sub: &'a Ty<'a>,
+    pub add_note: bool,
+}
+
+impl AddToDiagnostic for AddLifetimeParamsSuggestion<'_> {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        let mut mk_suggestion = || {
+            let (
+                hir::Ty { kind: hir::TyKind::Rptr(lifetime_sub, _), .. },
+                hir::Ty { kind: hir::TyKind::Rptr(lifetime_sup, _), .. },
+            ) = (self.ty_sub, self.ty_sup) else {
+                return false;
+            };
+
+            if !lifetime_sub.name.is_anonymous() || !lifetime_sup.name.is_anonymous() {
+                return false;
+            };
+
+            let Some(anon_reg) = self.tcx.is_suitable_region(self.sub) else {
+                return false;
+            };
+
+            let hir_id = self.tcx.hir().local_def_id_to_hir_id(anon_reg.def_id);
+
+            let node = self.tcx.hir().get(hir_id);
+            let is_impl = matches!(&node, hir::Node::ImplItem(_));
+            let generics = match node {
+                hir::Node::Item(&hir::Item {
+                    kind: hir::ItemKind::Fn(_, ref generics, ..),
+                    ..
+                })
+                | hir::Node::TraitItem(&hir::TraitItem { ref generics, .. })
+                | hir::Node::ImplItem(&hir::ImplItem { ref generics, .. }) => generics,
+                _ => return false,
+            };
+
+            let suggestion_param_name = generics
+                .params
+                .iter()
+                .filter(|p| matches!(p.kind, GenericParamKind::Lifetime { .. }))
+                .map(|p| p.name.ident().name)
+                .find(|i| *i != kw::UnderscoreLifetime);
+            let introduce_new = suggestion_param_name.is_none();
+            let suggestion_param_name =
+                suggestion_param_name.map(|n| n.to_string()).unwrap_or_else(|| "'a".to_owned());
+
+            debug!(?lifetime_sup.span);
+            debug!(?lifetime_sub.span);
+            let make_suggestion = |span: rustc_span::Span| {
+                if span.is_empty() {
+                    (span, format!("{}, ", suggestion_param_name))
+                } else if let Ok("&") = self.tcx.sess.source_map().span_to_snippet(span).as_deref()
+                {
+                    (span.shrink_to_hi(), format!("{} ", suggestion_param_name))
+                } else {
+                    (span, suggestion_param_name.clone())
+                }
+            };
+            let mut suggestions =
+                vec![make_suggestion(lifetime_sub.span), make_suggestion(lifetime_sup.span)];
+
+            if introduce_new {
+                let new_param_suggestion = if let Some(first) =
+                    generics.params.iter().find(|p| !p.name.ident().span.is_empty())
+                {
+                    (first.span.shrink_to_lo(), format!("{}, ", suggestion_param_name))
+                } else {
+                    (generics.span, format!("<{}>", suggestion_param_name))
+                };
+
+                suggestions.push(new_param_suggestion);
+            }
+
+            diag.multipart_suggestion(
+                fluent::infer::lifetime_param_suggestion,
+                suggestions,
+                Applicability::MaybeIncorrect,
+            );
+            diag.set_arg("is_impl", is_impl);
+            true
+        };
+        if mk_suggestion() && self.add_note {
+            diag.note(fluent::infer::lifetime_param_suggestion_elided);
+        }
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(infer::lifetime_mismatch, code = "E0623")]
+pub struct LifetimeMismatch<'a> {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub labels: LifetimeMismatchLabels,
+    #[subdiagnostic]
+    pub suggestion: AddLifetimeParamsSuggestion<'a>,
+}
+
+pub struct IntroducesStaticBecauseUnmetLifetimeReq {
+    pub unmet_requirements: MultiSpan,
+    pub binding_span: Span,
+}
+
+impl AddToDiagnostic for IntroducesStaticBecauseUnmetLifetimeReq {
+    fn add_to_diagnostic(mut self, diag: &mut rustc_errors::Diagnostic) {
+        self.unmet_requirements
+            .push_span_label(self.binding_span, fluent::infer::msl_introduces_static);
+        diag.span_note(self.unmet_requirements, fluent::infer::msl_unmet_req);
+    }
+}
+
+pub struct ImplNote {
+    pub impl_span: Option<Span>,
+}
+
+impl AddToDiagnostic for ImplNote {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        match self.impl_span {
+            Some(span) => diag.span_note(span, fluent::infer::msl_impl_note),
+            None => diag.note(fluent::infer::msl_impl_note),
+        };
+    }
+}
+
+pub enum TraitSubdiag {
+    Note { span: Span },
+    Sugg { span: Span },
+}
+
+// FIXME(#100717) used in `Vec<TraitSubdiag>` so requires eager translation/list support
+impl AddToDiagnostic for TraitSubdiag {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        match self {
+            TraitSubdiag::Note { span } => {
+                diag.span_note(span, "this has an implicit `'static` lifetime requirement");
+            }
+            TraitSubdiag::Sugg { span } => {
+                diag.span_suggestion_verbose(
+                    span,
+                    "consider relaxing the implicit `'static` requirement",
+                    " + '_".to_owned(),
+                    rustc_errors::Applicability::MaybeIncorrect,
+                );
+            }
+        }
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(infer::mismatched_static_lifetime)]
+pub struct MismatchedStaticLifetime<'a> {
+    #[primary_span]
+    pub cause_span: Span,
+    #[subdiagnostic]
+    pub unmet_lifetime_reqs: IntroducesStaticBecauseUnmetLifetimeReq,
+    #[subdiagnostic]
+    pub expl: Option<note_and_explain::RegionExplanation<'a>>,
+    #[subdiagnostic]
+    pub impl_note: ImplNote,
+    #[subdiagnostic]
+    pub trait_subdiags: Vec<TraitSubdiag>,
+}
diff --git a/compiler/rustc_infer/src/errors/note_and_explain.rs b/compiler/rustc_infer/src/errors/note_and_explain.rs
new file mode 100644
index 000000000000..7f54918f7361
--- /dev/null
+++ b/compiler/rustc_infer/src/errors/note_and_explain.rs
@@ -0,0 +1,172 @@
+use crate::infer::error_reporting::nice_region_error::find_anon_type;
+use rustc_errors::{self, fluent, AddToDiagnostic, IntoDiagnosticArg};
+use rustc_middle::ty::{self, TyCtxt};
+use rustc_span::{symbol::kw, Span};
+
+#[derive(Default)]
+struct DescriptionCtx<'a> {
+    span: Option<Span>,
+    kind: &'a str,
+    arg: String,
+    num_arg: u32,
+}
+
+impl<'a> DescriptionCtx<'a> {
+    fn new<'tcx>(
+        tcx: TyCtxt<'tcx>,
+        region: ty::Region<'tcx>,
+        alt_span: Option<Span>,
+    ) -> Option<Self> {
+        let mut me = DescriptionCtx::default();
+        me.span = alt_span;
+        match *region {
+            ty::ReEarlyBound(_) | ty::ReFree(_) => {
+                return Self::from_early_bound_and_free_regions(tcx, region);
+            }
+            ty::ReStatic => {
+                me.kind = "restatic";
+            }
+
+            ty::RePlaceholder(_) => return None,
+
+            // FIXME(#13998) RePlaceholder should probably print like
+            // ReFree rather than dumping Debug output on the user.
+            //
+            // We shouldn't really be having unification failures with ReVar
+            // and ReLateBound though.
+            ty::ReVar(_) | ty::ReLateBound(..) | ty::ReErased => {
+                me.kind = "revar";
+                me.arg = format!("{:?}", region);
+            }
+        };
+        Some(me)
+    }
+
+    fn from_early_bound_and_free_regions<'tcx>(
+        tcx: TyCtxt<'tcx>,
+        region: ty::Region<'tcx>,
+    ) -> Option<Self> {
+        let mut me = DescriptionCtx::default();
+        let scope = region.free_region_binding_scope(tcx).expect_local();
+        match *region {
+            ty::ReEarlyBound(ref br) => {
+                let mut sp = tcx.def_span(scope);
+                if let Some(param) =
+                    tcx.hir().get_generics(scope).and_then(|generics| generics.get_named(br.name))
+                {
+                    sp = param.span;
+                }
+                if br.has_name() {
+                    me.kind = "as_defined";
+                    me.arg = br.name.to_string();
+                } else {
+                    me.kind = "as_defined_anon";
+                };
+                me.span = Some(sp)
+            }
+            ty::ReFree(ref fr) => {
+                if !fr.bound_region.is_named()
+                    && let Some((ty, _)) = find_anon_type(tcx, region, &fr.bound_region)
+                {
+                    me.kind = "defined_here";
+                    me.span = Some(ty.span);
+                } else {
+                    match fr.bound_region {
+                        ty::BoundRegionKind::BrNamed(_, name) => {
+                            let mut sp = tcx.def_span(scope);
+                            if let Some(param) =
+                                tcx.hir().get_generics(scope).and_then(|generics| generics.get_named(name))
+                            {
+                                sp = param.span;
+                            }
+                            if name == kw::UnderscoreLifetime {
+                                me.kind = "as_defined_anon";
+                            } else {
+                                me.kind = "as_defined";
+                                me.arg = name.to_string();
+                            };
+                            me.span = Some(sp);
+                        }
+                        ty::BrAnon(idx) => {
+                            me.kind = "anon_num_here";
+                            me.num_arg = idx+1;
+                            me.span = Some(tcx.def_span(scope));
+                        },
+                        _ => {
+                            me.kind = "defined_here_reg";
+                            me.arg = region.to_string();
+                            me.span = Some(tcx.def_span(scope));
+                        },
+                    }
+                }
+            }
+            _ => bug!(),
+        }
+        Some(me)
+    }
+
+    fn add_to(self, diag: &mut rustc_errors::Diagnostic) {
+        diag.set_arg("desc_kind", self.kind);
+        diag.set_arg("desc_arg", self.arg);
+        diag.set_arg("desc_num_arg", self.num_arg);
+    }
+}
+
+pub enum PrefixKind {
+    Empty,
+}
+
+pub enum SuffixKind {
+    Continues,
+}
+
+impl IntoDiagnosticArg for PrefixKind {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        let kind = match self {
+            Self::Empty => "empty",
+        }
+        .into();
+        rustc_errors::DiagnosticArgValue::Str(kind)
+    }
+}
+
+impl IntoDiagnosticArg for SuffixKind {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        let kind = match self {
+            Self::Continues => "continues",
+        }
+        .into();
+        rustc_errors::DiagnosticArgValue::Str(kind)
+    }
+}
+
+pub struct RegionExplanation<'a> {
+    desc: DescriptionCtx<'a>,
+    prefix: PrefixKind,
+    suffix: SuffixKind,
+}
+
+impl RegionExplanation<'_> {
+    pub fn new<'tcx>(
+        tcx: TyCtxt<'tcx>,
+        region: ty::Region<'tcx>,
+        alt_span: Option<Span>,
+        prefix: PrefixKind,
+        suffix: SuffixKind,
+    ) -> Option<Self> {
+        Some(Self { desc: DescriptionCtx::new(tcx, region, alt_span)?, prefix, suffix })
+    }
+}
+
+impl AddToDiagnostic for RegionExplanation<'_> {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        if let Some(span) = self.desc.span {
+            diag.span_note(span, fluent::infer::region_explanation);
+        } else {
+            diag.note(fluent::infer::region_explanation);
+        }
+        self.desc.add_to(diag);
+        diag.set_arg("pref_kind", self.prefix);
+        diag.set_arg("suff_kind", self.suffix);
+    }
+}
diff --git a/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs b/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
index 46f8c0e8d8b9..9488d0a6cbb6 100644
--- a/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
+++ b/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
@@ -180,11 +180,7 @@ impl CanonicalizeMode for CanonicalizeQueryResponse {
         r: ty::Region<'tcx>,
     ) -> ty::Region<'tcx> {
         match *r {
-            ty::ReFree(_)
-            | ty::ReErased
-            | ty::ReStatic
-            | ty::ReEmpty(ty::UniverseIndex::ROOT)
-            | ty::ReEarlyBound(..) => r,
+            ty::ReFree(_) | ty::ReErased | ty::ReStatic | ty::ReEarlyBound(..) => r,
 
             ty::RePlaceholder(placeholder) => canonicalizer.canonical_var_for_region(
                 CanonicalVarInfo { kind: CanonicalVarKind::PlaceholderRegion(placeholder) },
@@ -199,10 +195,6 @@ impl CanonicalizeMode for CanonicalizeQueryResponse {
                 )
             }
 
-            ty::ReEmpty(ui) => {
-                bug!("canonicalizing 'empty in universe {:?}", ui) // FIXME
-            }
-
             _ => {
                 // Other than `'static` or `'empty`, the query
                 // response should be executing in a fully
@@ -381,7 +373,6 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
             ty::ReStatic
             | ty::ReEarlyBound(..)
             | ty::ReFree(_)
-            | ty::ReEmpty(_)
             | ty::RePlaceholder(..)
             | ty::ReErased => self.canonicalize_mode.canonicalize_free_region(self, r),
         }
diff --git a/compiler/rustc_infer/src/infer/canonical/query_response.rs b/compiler/rustc_infer/src/infer/canonical/query_response.rs
index 64c759f73d41..56e834898795 100644
--- a/compiler/rustc_infer/src/infer/canonical/query_response.rs
+++ b/compiler/rustc_infer/src/infer/canonical/query_response.rs
@@ -22,6 +22,7 @@ use rustc_data_structures::captures::Captures;
 use rustc_index::vec::Idx;
 use rustc_index::vec::IndexVec;
 use rustc_middle::arena::ArenaAllocatable;
+use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::relate::TypeRelation;
@@ -129,7 +130,9 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         let region_constraints = self.with_region_constraints(|region_constraints| {
             make_query_region_constraints(
                 tcx,
-                region_obligations.iter().map(|r_o| (r_o.sup_type, r_o.sub_region)),
+                region_obligations
+                    .iter()
+                    .map(|r_o| (r_o.sup_type, r_o.sub_region, r_o.origin.to_constraint_category())),
                 region_constraints,
             )
         });
@@ -248,6 +251,8 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         // the original values `v_o` that was canonicalized into a
         // variable...
 
+        let constraint_category = cause.to_constraint_category();
+
         for (index, original_value) in original_values.var_values.iter().enumerate() {
             // ...with the value `v_r` of that variable from the query.
             let result_value = query_response.substitute_projected(self.tcx, &result_subst, |v| {
@@ -263,12 +268,14 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 (GenericArgKind::Lifetime(v_o), GenericArgKind::Lifetime(v_r)) => {
                     // To make `v_o = v_r`, we emit `v_o: v_r` and `v_r: v_o`.
                     if v_o != v_r {
-                        output_query_region_constraints
-                            .outlives
-                            .push(ty::Binder::dummy(ty::OutlivesPredicate(v_o.into(), v_r)));
-                        output_query_region_constraints
-                            .outlives
-                            .push(ty::Binder::dummy(ty::OutlivesPredicate(v_r.into(), v_o)));
+                        output_query_region_constraints.outlives.push((
+                            ty::Binder::dummy(ty::OutlivesPredicate(v_o.into(), v_r)),
+                            constraint_category,
+                        ));
+                        output_query_region_constraints.outlives.push((
+                            ty::Binder::dummy(ty::OutlivesPredicate(v_r.into(), v_o)),
+                            constraint_category,
+                        ));
                     }
                 }
 
@@ -314,7 +321,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 // Screen out `'a: 'a` cases -- we skip the binder here but
                 // only compare the inner values to one another, so they are still at
                 // consistent binding levels.
-                let ty::OutlivesPredicate(k1, r2) = r_c.skip_binder();
+                let ty::OutlivesPredicate(k1, r2) = r_c.0.skip_binder();
                 if k1 != r2.into() { Some(r_c) } else { None }
             }),
         );
@@ -559,7 +566,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         cause: ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> Obligation<'tcx, ty::Predicate<'tcx>> {
-        let ty::OutlivesPredicate(k1, r2) = predicate.skip_binder();
+        let ty::OutlivesPredicate(k1, r2) = predicate.0.skip_binder();
 
         let atom = match k1.unpack() {
             GenericArgKind::Lifetime(r1) => {
@@ -574,7 +581,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 span_bug!(cause.span, "unexpected const outlives {:?}", predicate);
             }
         };
-        let predicate = predicate.rebind(atom).to_predicate(self.tcx);
+        let predicate = predicate.0.rebind(atom).to_predicate(self.tcx);
 
         Obligation::new(cause, param_env, predicate)
     }
@@ -625,7 +632,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
 /// creates query region constraints.
 pub fn make_query_region_constraints<'tcx>(
     tcx: TyCtxt<'tcx>,
-    outlives_obligations: impl Iterator<Item = (Ty<'tcx>, ty::Region<'tcx>)>,
+    outlives_obligations: impl Iterator<Item = (Ty<'tcx>, ty::Region<'tcx>, ConstraintCategory<'tcx>)>,
     region_constraints: &RegionConstraintData<'tcx>,
 ) -> QueryRegionConstraints<'tcx> {
     let RegionConstraintData { constraints, verifys, givens, member_constraints } =
@@ -638,26 +645,31 @@ pub fn make_query_region_constraints<'tcx>(
 
     let outlives: Vec<_> = constraints
         .iter()
-        .map(|(k, _)| match *k {
-            // Swap regions because we are going from sub (<=) to outlives
-            // (>=).
-            Constraint::VarSubVar(v1, v2) => ty::OutlivesPredicate(
-                tcx.mk_region(ty::ReVar(v2)).into(),
-                tcx.mk_region(ty::ReVar(v1)),
-            ),
-            Constraint::VarSubReg(v1, r2) => {
-                ty::OutlivesPredicate(r2.into(), tcx.mk_region(ty::ReVar(v1)))
-            }
-            Constraint::RegSubVar(r1, v2) => {
-                ty::OutlivesPredicate(tcx.mk_region(ty::ReVar(v2)).into(), r1)
-            }
-            Constraint::RegSubReg(r1, r2) => ty::OutlivesPredicate(r2.into(), r1),
+        .map(|(k, origin)| {
+            // no bound vars in the code above
+            let constraint = ty::Binder::dummy(match *k {
+                // Swap regions because we are going from sub (<=) to outlives
+                // (>=).
+                Constraint::VarSubVar(v1, v2) => ty::OutlivesPredicate(
+                    tcx.mk_region(ty::ReVar(v2)).into(),
+                    tcx.mk_region(ty::ReVar(v1)),
+                ),
+                Constraint::VarSubReg(v1, r2) => {
+                    ty::OutlivesPredicate(r2.into(), tcx.mk_region(ty::ReVar(v1)))
+                }
+                Constraint::RegSubVar(r1, v2) => {
+                    ty::OutlivesPredicate(tcx.mk_region(ty::ReVar(v2)).into(), r1)
+                }
+                Constraint::RegSubReg(r1, r2) => ty::OutlivesPredicate(r2.into(), r1),
+            });
+            (constraint, origin.to_constraint_category())
         })
-        .map(ty::Binder::dummy) // no bound vars in the code above
         .chain(
             outlives_obligations
-                .map(|(ty, r)| ty::OutlivesPredicate(ty.into(), r))
-                .map(ty::Binder::dummy), // no bound vars in the code above
+                // no bound vars in the code above
+                .map(|(ty, r, constraint_category)| {
+                    (ty::Binder::dummy(ty::OutlivesPredicate(ty.into(), r)), constraint_category)
+                }),
         )
         .collect();
 
diff --git a/compiler/rustc_infer/src/infer/canonical/substitute.rs b/compiler/rustc_infer/src/infer/canonical/substitute.rs
index 34b6113427d4..389afe22eb76 100644
--- a/compiler/rustc_infer/src/infer/canonical/substitute.rs
+++ b/compiler/rustc_infer/src/infer/canonical/substitute.rs
@@ -72,15 +72,16 @@ where
         value
     } else {
         let delegate = FnMutDelegate {
-            regions: |br: ty::BoundRegion| match var_values.var_values[br.var].unpack() {
+            regions: &mut |br: ty::BoundRegion| match var_values.var_values[br.var].unpack() {
                 GenericArgKind::Lifetime(l) => l,
                 r => bug!("{:?} is a region but value is {:?}", br, r),
             },
-            types: |bound_ty: ty::BoundTy| match var_values.var_values[bound_ty.var].unpack() {
+            types: &mut |bound_ty: ty::BoundTy| match var_values.var_values[bound_ty.var].unpack() {
                 GenericArgKind::Type(ty) => ty,
                 r => bug!("{:?} is a type but value is {:?}", bound_ty, r),
             },
-            consts: |bound_ct: ty::BoundVar, _| match var_values.var_values[bound_ct].unpack() {
+            consts: &mut |bound_ct: ty::BoundVar, _| match var_values.var_values[bound_ct].unpack()
+            {
                 GenericArgKind::Const(ct) => ct,
                 c => bug!("{:?} is a const but value is {:?}", bound_ct, c),
             },
diff --git a/compiler/rustc_infer/src/infer/combine.rs b/compiler/rustc_infer/src/infer/combine.rs
index 8bf1de34a9b5..9488f1f6bfc4 100644
--- a/compiler/rustc_infer/src/infer/combine.rs
+++ b/compiler/rustc_infer/src/infer/combine.rs
@@ -147,11 +147,7 @@ impl<'infcx, 'tcx> InferCtxt<'infcx, 'tcx> {
                 ty::ConstKind::Infer(InferConst::Var(a_vid)),
                 ty::ConstKind::Infer(InferConst::Var(b_vid)),
             ) => {
-                self.inner
-                    .borrow_mut()
-                    .const_unification_table()
-                    .unify_var_var(a_vid, b_vid)
-                    .map_err(|e| const_unification_error(a_is_expected, e))?;
+                self.inner.borrow_mut().const_unification_table().union(a_vid, b_vid);
                 return Ok(a);
             }
 
@@ -246,21 +242,17 @@ impl<'infcx, 'tcx> InferCtxt<'infcx, 'tcx> {
         let value = ConstInferUnifier { infcx: self, span, param_env, for_universe, target_vid }
             .relate(ct, ct)?;
 
-        self.inner
-            .borrow_mut()
-            .const_unification_table()
-            .unify_var_value(
-                target_vid,
-                ConstVarValue {
-                    origin: ConstVariableOrigin {
-                        kind: ConstVariableOriginKind::ConstInference,
-                        span: DUMMY_SP,
-                    },
-                    val: ConstVariableValue::Known { value },
+        self.inner.borrow_mut().const_unification_table().union_value(
+            target_vid,
+            ConstVarValue {
+                origin: ConstVariableOrigin {
+                    kind: ConstVariableOriginKind::ConstInference,
+                    span: DUMMY_SP,
                 },
-            )
-            .map(|()| value)
-            .map_err(|e| const_unification_error(vid_is_expected, e))
+                val: ConstVariableValue::Known { value },
+            },
+        );
+        Ok(value)
     }
 
     fn unify_integral_variable(
@@ -391,7 +383,7 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
     /// Preconditions:
     ///
     /// - `for_vid` is a "root vid"
-    #[instrument(skip(self), level = "trace")]
+    #[instrument(skip(self), level = "trace", ret)]
     fn generalize(
         &self,
         ty: Ty<'tcx>,
@@ -435,15 +427,8 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
             cache: SsoHashMap::new(),
         };
 
-        let ty = match generalize.relate(ty, ty) {
-            Ok(ty) => ty,
-            Err(e) => {
-                debug!(?e, "failure");
-                return Err(e);
-            }
-        };
+        let ty = generalize.relate(ty, ty)?;
         let needs_wf = generalize.needs_wf;
-        trace!(?ty, ?needs_wf, "success");
         Ok(Generalization { ty, needs_wf })
     }
 
@@ -493,12 +478,13 @@ struct Generalizer<'cx, 'tcx> {
 
     param_env: ty::ParamEnv<'tcx>,
 
-    cache: SsoHashMap<Ty<'tcx>, RelateResult<'tcx, Ty<'tcx>>>,
+    cache: SsoHashMap<Ty<'tcx>, Ty<'tcx>>,
 }
 
 /// Result from a generalization operation. This includes
 /// not only the generalized type, but also a bool flag
 /// indicating whether further WF checks are needed.
+#[derive(Debug)]
 struct Generalization<'tcx> {
     ty: Ty<'tcx>,
 
@@ -599,8 +585,8 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
     fn tys(&mut self, t: Ty<'tcx>, t2: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         assert_eq!(t, t2); // we are abusing TypeRelation here; both LHS and RHS ought to be ==
 
-        if let Some(result) = self.cache.get(&t) {
-            return result.clone();
+        if let Some(&result) = self.cache.get(&t) {
+            return Ok(result);
         }
         debug!("generalize: t={:?}", t);
 
@@ -670,10 +656,10 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
                 Ok(t)
             }
             _ => relate::super_relate_tys(self, t, t),
-        };
+        }?;
 
-        self.cache.insert(t, result.clone());
-        return result;
+        self.cache.insert(t, result);
+        Ok(result)
     }
 
     fn regions(
@@ -694,7 +680,6 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
 
             ty::RePlaceholder(..)
             | ty::ReVar(..)
-            | ty::ReEmpty(_)
             | ty::ReStatic
             | ty::ReEarlyBound(..)
             | ty::ReFree(..) => {
@@ -749,10 +734,7 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
                     }
                 }
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
-                if self.tcx().lazy_normalization() =>
-            {
-                assert_eq!(promoted, None);
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 let substs = self.relate_with_variance(
                     ty::Variance::Invariant,
                     ty::VarianceDiagInfo::default(),
@@ -761,7 +743,7 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
                 )?;
                 Ok(self.tcx().mk_const(ty::ConstS {
                     ty: c.ty(),
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }),
+                    kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }),
                 }))
             }
             _ => relate::super_relate_consts(self, c, c),
@@ -776,13 +758,6 @@ pub trait ConstEquateRelation<'tcx>: TypeRelation<'tcx> {
     fn const_equate_obligation(&mut self, a: ty::Const<'tcx>, b: ty::Const<'tcx>);
 }
 
-pub fn const_unification_error<'tcx>(
-    a_is_expected: bool,
-    (a, b): (ty::Const<'tcx>, ty::Const<'tcx>),
-) -> TypeError<'tcx> {
-    TypeError::ConstMismatch(ExpectedFound::new(a_is_expected, a, b))
-}
-
 fn int_unification_error<'tcx>(
     a_is_expected: bool,
     v: (ty::IntVarValue, ty::IntVarValue),
@@ -856,10 +831,9 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
         Ok(a.rebind(self.relate(a.skip_binder(), b.skip_binder())?))
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     fn tys(&mut self, t: Ty<'tcx>, _t: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         debug_assert_eq!(t, _t);
-        debug!("ConstInferUnifier: t={:?}", t);
 
         match t.kind() {
             &ty::Infer(ty::TyVar(vid)) => {
@@ -883,12 +857,7 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
                             .borrow_mut()
                             .type_variables()
                             .new_var(self.for_universe, origin);
-                        let u = self.tcx().mk_ty_var(new_var_id);
-                        debug!(
-                            "ConstInferUnifier: replacing original vid={:?} with new={:?}",
-                            vid, u
-                        );
-                        Ok(u)
+                        Ok(self.tcx().mk_ty_var(new_var_id))
                     }
                 }
             }
@@ -914,7 +883,6 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
 
             ty::RePlaceholder(..)
             | ty::ReVar(..)
-            | ty::ReEmpty(_)
             | ty::ReStatic
             | ty::ReEarlyBound(..)
             | ty::ReFree(..) => {
@@ -932,14 +900,13 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn consts(
         &mut self,
         c: ty::Const<'tcx>,
         _c: ty::Const<'tcx>,
     ) -> RelateResult<'tcx, ty::Const<'tcx>> {
         debug_assert_eq!(c, _c);
-        debug!("ConstInferUnifier: c={:?}", c);
 
         match c.kind() {
             ty::ConstKind::Infer(InferConst::Var(vid)) => {
@@ -980,19 +947,17 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
                     }
                 }
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
-                if self.tcx().lazy_normalization() =>
-            {
-                assert_eq!(promoted, None);
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 let substs = self.relate_with_variance(
                     ty::Variance::Invariant,
                     ty::VarianceDiagInfo::default(),
                     substs,
                     substs,
                 )?;
+
                 Ok(self.tcx().mk_const(ty::ConstS {
                     ty: c.ty(),
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }),
+                    kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }),
                 }))
             }
             _ => relate::super_relate_consts(self, c, c),
diff --git a/compiler/rustc_infer/src/infer/equate.rs b/compiler/rustc_infer/src/infer/equate.rs
index 3b1798ca7374..59728148a84c 100644
--- a/compiler/rustc_infer/src/infer/equate.rs
+++ b/compiler/rustc_infer/src/infer/equate.rs
@@ -110,6 +110,25 @@ impl<'tcx> TypeRelation<'tcx> for Equate<'_, '_, 'tcx> {
                         .obligations,
                 );
             }
+            // Optimization of GeneratorWitness relation since we know that all
+            // free regions are replaced with bound regions during construction.
+            // This greatly speeds up equating of GeneratorWitness.
+            (&ty::GeneratorWitness(a_types), &ty::GeneratorWitness(b_types)) => {
+                let a_types = infcx.tcx.anonymize_bound_vars(a_types);
+                let b_types = infcx.tcx.anonymize_bound_vars(b_types);
+                if a_types.bound_vars() == b_types.bound_vars() {
+                    let (a_types, b_types) = infcx.replace_bound_vars_with_placeholders(
+                        a_types.map_bound(|a_types| (a_types, b_types.skip_binder())),
+                    );
+                    for (a, b) in std::iter::zip(a_types, b_types) {
+                        self.relate(a, b)?;
+                    }
+                } else {
+                    return Err(ty::error::TypeError::Sorts(ty::relate::expected_found(
+                        self, a, b,
+                    )));
+                }
+            }
 
             _ => {
                 self.fields.infcx.super_combine_tys(self, a, b)?;
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index 3a6119a62736..99469d1e1e7d 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -51,6 +51,7 @@ use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePa
 
 use crate::infer;
 use crate::infer::error_reporting::nice_region_error::find_anon_type::find_anon_type;
+use crate::infer::ExpectedFound;
 use crate::traits::error_reporting::report_object_safety_error;
 use crate::traits::{
     IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode,
@@ -61,6 +62,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{pluralize, struct_span_err, Diagnostic, ErrorGuaranteed, IntoDiagnosticArg};
 use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString, MultiSpan};
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::Node;
@@ -68,8 +70,8 @@ use rustc_middle::dep_graph::DepContext;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::relate::{self, RelateResult, TypeRelation};
 use rustc_middle::ty::{
-    self, error::TypeError, Binder, List, Region, Subst, Ty, TyCtxt, TypeFoldable,
-    TypeSuperVisitable, TypeVisitable,
+    self, error::TypeError, Binder, List, Region, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
+    TypeVisitable,
 };
 use rustc_span::{sym, symbol::kw, BytePos, DesugaringKind, Pos, Span};
 use rustc_target::spec::abi;
@@ -96,11 +98,6 @@ pub(super) fn note_and_explain_region<'tcx>(
             msg_span_from_free_region(tcx, region, alt_span)
         }
 
-        ty::ReEmpty(ty::UniverseIndex::ROOT) => ("the empty lifetime".to_owned(), alt_span),
-
-        // uh oh, hope no user ever sees THIS
-        ty::ReEmpty(ui) => (format!("the empty lifetime in universe {:?}", ui), alt_span),
-
         ty::RePlaceholder(_) => return,
 
         // FIXME(#13998) RePlaceholder should probably print like
@@ -139,8 +136,6 @@ fn msg_span_from_free_region<'tcx>(
             (msg, Some(span))
         }
         ty::ReStatic => ("the static lifetime".to_owned(), alt_span),
-        ty::ReEmpty(ty::UniverseIndex::ROOT) => ("an empty lifetime".to_owned(), alt_span),
-        ty::ReEmpty(ui) => (format!("an empty lifetime in universe {:?}", ui), alt_span),
         _ => bug!("{:?}", region),
     }
 }
@@ -250,17 +245,7 @@ pub fn unexpected_hidden_region_diagnostic<'tcx>(
 
     // Explain the region we are capturing.
     match *hidden_region {
-        ty::ReEmpty(ty::UniverseIndex::ROOT) => {
-            // All lifetimes shorter than the function body are `empty` in
-            // lexical region resolution. The default explanation of "an empty
-            // lifetime" isn't really accurate here.
-            let message = format!(
-                "hidden type `{}` captures lifetime smaller than the function body",
-                hidden_ty
-            );
-            err.span_note(span, &message);
-        }
-        ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReStatic | ty::ReEmpty(_) => {
+        ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReStatic => {
             // Assuming regionck succeeded (*), we ought to always be
             // capturing *some* region from the fn header, and hence it
             // ought to be free. So under normal circumstances, we will go
@@ -386,7 +371,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     RegionResolutionError::UpperBoundUniverseConflict(
                         _,
                         _,
-                        var_universe,
+                        _,
                         sup_origin,
                         sup_r,
                     ) => {
@@ -397,7 +382,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         // placeholder. In practice, we expect more
                         // tailored errors that don't really use this
                         // value.
-                        let sub_r = self.tcx.mk_region(ty::ReEmpty(var_universe));
+                        let sub_r = self.tcx.lifetimes.re_erased;
 
                         self.report_placeholder_failure(sup_origin, sub_r, sup_r).emit();
                     }
@@ -1434,7 +1419,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// the message in `secondary_span` as the primary label, and apply the message that would
     /// otherwise be used for the primary label on the `secondary_span` `Span`. This applies on
     /// E0271, like `src/test/ui/issues/issue-39970.stderr`.
-    #[tracing::instrument(
+    #[instrument(
         level = "debug",
         skip(self, diag, secondary_span, swap_secondary_and_primary, prefer_label)
     )]
@@ -1586,28 +1571,31 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             Some(values) => {
                 let values = self.resolve_vars_if_possible(values);
                 let (is_simple_error, exp_found) = match values {
-                    ValuePairs::Terms(infer::ExpectedFound {
-                        expected: ty::Term::Ty(expected),
-                        found: ty::Term::Ty(found),
-                    }) => {
-                        let is_simple_err = expected.is_simple_text() && found.is_simple_text();
-                        OpaqueTypesVisitor::visit_expected_found(self.tcx, expected, found, span)
-                            .report(diag);
+                    ValuePairs::Terms(infer::ExpectedFound { expected, found }) => {
+                        match (expected.unpack(), found.unpack()) {
+                            (ty::TermKind::Ty(expected), ty::TermKind::Ty(found)) => {
+                                let is_simple_err =
+                                    expected.is_simple_text() && found.is_simple_text();
+                                OpaqueTypesVisitor::visit_expected_found(
+                                    self.tcx, expected, found, span,
+                                )
+                                .report(diag);
 
-                        (
-                            is_simple_err,
-                            Mismatch::Variable(infer::ExpectedFound { expected, found }),
-                        )
+                                (
+                                    is_simple_err,
+                                    Mismatch::Variable(infer::ExpectedFound { expected, found }),
+                                )
+                            }
+                            (ty::TermKind::Const(_), ty::TermKind::Const(_)) => {
+                                (false, Mismatch::Fixed("constant"))
+                            }
+                            _ => (false, Mismatch::Fixed("type")),
+                        }
                     }
-                    ValuePairs::Terms(infer::ExpectedFound {
-                        expected: ty::Term::Const(_),
-                        found: ty::Term::Const(_),
-                    }) => (false, Mismatch::Fixed("constant")),
                     ValuePairs::TraitRefs(_) | ValuePairs::PolyTraitRefs(_) => {
                         (false, Mismatch::Fixed("trait"))
                     }
                     ValuePairs::Regions(_) => (false, Mismatch::Fixed("lifetime")),
-                    _ => (false, Mismatch::Fixed("type")),
                 };
                 let vals = match self.values_str(values) {
                     Some((expected, found)) => Some((expected, found)),
@@ -1666,8 +1654,114 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 ),
                 Mismatch::Fixed(s) => (s.into(), s.into(), None),
             };
-            match (&terr, expected == found) {
-                (TypeError::Sorts(values), extra) => {
+
+            enum Similar<'tcx> {
+                Adts { expected: ty::AdtDef<'tcx>, found: ty::AdtDef<'tcx> },
+                PrimitiveFound { expected: ty::AdtDef<'tcx>, found: Ty<'tcx> },
+                PrimitiveExpected { expected: Ty<'tcx>, found: ty::AdtDef<'tcx> },
+            }
+
+            let similarity = |ExpectedFound { expected, found }: ExpectedFound<Ty<'tcx>>| {
+                if let ty::Adt(expected, _) = expected.kind() && let Some(primitive) = found.primitive_symbol() {
+                    let path = self.tcx.def_path(expected.did()).data;
+                    let name = path.last().unwrap().data.get_opt_name();
+                    if name == Some(primitive) {
+                        return Some(Similar::PrimitiveFound { expected: *expected, found });
+                    }
+                } else if let Some(primitive) = expected.primitive_symbol() && let ty::Adt(found, _) = found.kind() {
+                    let path = self.tcx.def_path(found.did()).data;
+                    let name = path.last().unwrap().data.get_opt_name();
+                    if name == Some(primitive) {
+                        return Some(Similar::PrimitiveExpected { expected, found: *found });
+                    }
+                } else if let ty::Adt(expected, _) = expected.kind() && let ty::Adt(found, _) = found.kind() {
+                    if !expected.did().is_local() && expected.did().krate == found.did().krate {
+                        // Most likely types from different versions of the same crate
+                        // are in play, in which case this message isn't so helpful.
+                        // A "perhaps two different versions..." error is already emitted for that.
+                        return None;
+                    }
+                    let f_path = self.tcx.def_path(found.did()).data;
+                    let e_path = self.tcx.def_path(expected.did()).data;
+
+                    if let (Some(e_last), Some(f_last)) = (e_path.last(), f_path.last()) && e_last ==  f_last {
+                        return Some(Similar::Adts{expected: *expected, found: *found});
+                    }
+                }
+                None
+            };
+
+            match terr {
+                // If two types mismatch but have similar names, mention that specifically.
+                TypeError::Sorts(values) if let Some(s) = similarity(values) => {
+                    let diagnose_primitive =
+                        |prim: Ty<'tcx>,
+                         shadow: Ty<'tcx>,
+                         defid: DefId,
+                         diagnostic: &mut Diagnostic| {
+                            let name = shadow.sort_string(self.tcx);
+                            diagnostic.note(format!(
+                            "{prim} and {name} have similar names, but are actually distinct types"
+                        ));
+                            diagnostic
+                                .note(format!("{prim} is a primitive defined by the language"));
+                            let def_span = self.tcx.def_span(defid);
+                            let msg = if defid.is_local() {
+                                format!("{name} is defined in the current crate")
+                            } else {
+                                let crate_name = self.tcx.crate_name(defid.krate);
+                                format!("{name} is defined in crate `{crate_name}")
+                            };
+                            diagnostic.span_note(def_span, msg);
+                        };
+
+                    let diagnose_adts =
+                        |expected_adt : ty::AdtDef<'tcx>,
+                         found_adt: ty::AdtDef<'tcx>,
+                         diagnostic: &mut Diagnostic| {
+                            let found_name = values.found.sort_string(self.tcx);
+                            let expected_name = values.expected.sort_string(self.tcx);
+
+                            let found_defid = found_adt.did();
+                            let expected_defid = expected_adt.did();
+
+                            diagnostic.note(format!("{found_name} and {expected_name} have similar names, but are actually distinct types"));
+                            for (defid, name) in
+                                [(found_defid, found_name), (expected_defid, expected_name)]
+                            {
+                                let def_span = self.tcx.def_span(defid);
+
+                                let msg = if found_defid.is_local() && expected_defid.is_local() {
+                                    let module = self
+                                        .tcx
+                                        .parent_module_from_def_id(defid.expect_local())
+                                        .to_def_id();
+                                    let module_name = self.tcx.def_path(module).to_string_no_crate_verbose();
+                                    format!("{name} is defined in module `crate{module_name}` of the current crate")
+                                } else if defid.is_local() {
+                                    format!("{name} is defined in the current crate")
+                                } else {
+                                    let crate_name = self.tcx.crate_name(defid.krate);
+                                    format!("{name} is defined in crate `{crate_name}`")
+                                };
+                                diagnostic.span_note(def_span, msg);
+                            }
+                        };
+
+                    match s {
+                        Similar::Adts{expected, found} => {
+                            diagnose_adts(expected, found, diag)
+                        }
+                        Similar::PrimitiveFound{expected, found: prim} => {
+                            diagnose_primitive(prim, values.expected, expected.did(), diag)
+                        }
+                        Similar::PrimitiveExpected{expected: prim, found} => {
+                            diagnose_primitive(prim, values.found, found.did(), diag)
+                        }
+                    }
+                }
+                TypeError::Sorts(values) => {
+                    let extra = expected == found;
                     let sort_string = |ty: Ty<'tcx>| match (extra, ty.kind()) {
                         (true, ty::Opaque(def_id, _)) => {
                             let sm = self.tcx.sess.source_map();
@@ -1679,6 +1773,19 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                 pos.col.to_usize() + 1,
                             )
                         }
+                        (true, ty::Projection(proj))
+                            if self.tcx.def_kind(proj.item_def_id)
+                                == DefKind::ImplTraitPlaceholder =>
+                        {
+                            let sm = self.tcx.sess.source_map();
+                            let pos = sm.lookup_char_pos(self.tcx.def_span(proj.item_def_id).lo());
+                            format!(
+                                " (trait associated opaque type at <{}:{}:{}>)",
+                                sm.filename_for_diagnostics(&pos.file.name),
+                                pos.line,
+                                pos.col.to_usize() + 1,
+                            )
+                        }
                         (true, _) => format!(" ({})", ty.sort_string(self.tcx)),
                         (false, _) => "".to_string(),
                     };
@@ -1707,10 +1814,10 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         );
                     }
                 }
-                (TypeError::ObjectUnsafeCoercion(_), _) => {
+                TypeError::ObjectUnsafeCoercion(_) => {
                     diag.note_unsuccessful_coercion(found, expected);
                 }
-                (_, _) => {
+                _ => {
                     debug!(
                         "note_type_err: exp_found={:?}, expected={:?} found={:?}",
                         exp_found, expected, found
@@ -2273,11 +2380,11 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             return None;
         }
 
-        Some(match (exp_found.expected, exp_found.found) {
-            (ty::Term::Ty(expected), ty::Term::Ty(found)) => self.cmp(expected, found),
-            (expected, found) => (
-                DiagnosticStyledString::highlighted(expected.to_string()),
-                DiagnosticStyledString::highlighted(found.to_string()),
+        Some(match (exp_found.expected.unpack(), exp_found.found.unpack()) {
+            (ty::TermKind::Ty(expected), ty::TermKind::Ty(found)) => self.cmp(expected, found),
+            _ => (
+                DiagnosticStyledString::highlighted(exp_found.expected.to_string()),
+                DiagnosticStyledString::highlighted(exp_found.found.to_string()),
             ),
         })
     }
@@ -2333,7 +2440,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         // We do this to avoid suggesting code that ends up as `T: 'a'b`,
                         // instead we suggest `T: 'a + 'b` in that case.
                         let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
-                        let ast_generics = self.tcx.hir().get_generics(hir_id.owner);
+                        let ast_generics = self.tcx.hir().get_generics(hir_id.owner.def_id);
                         let bounds =
                             ast_generics.and_then(|g| g.bounds_span_for_suggestions(def_id));
                         // `sp` only covers `T`, change it so that it covers
@@ -2374,6 +2481,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let labeled_user_string = match bound_kind {
             GenericKind::Param(ref p) => format!("the parameter type `{}`", p),
             GenericKind::Projection(ref p) => format!("the associated type `{}`", p),
+            GenericKind::Opaque(def_id, substs) => {
+                format!("the opaque type `{}`", self.tcx.def_path_str_with_substs(def_id, substs))
+            }
         };
 
         if let Some(SubregionOrigin::CompareImplItemObligation {
@@ -2395,19 +2505,23 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             type_param_span: Option<(Span, bool)>,
             bound_kind: GenericKind<'tcx>,
             sub: S,
+            add_lt_sugg: Option<(Span, String)>,
         ) {
             let msg = "consider adding an explicit lifetime bound";
             if let Some((sp, has_lifetimes)) = type_param_span {
                 let suggestion =
                     if has_lifetimes { format!(" + {}", sub) } else { format!(": {}", sub) };
-                err.span_suggestion_verbose(
-                    sp,
-                    &format!("{}...", msg),
-                    suggestion,
+                let mut suggestions = vec![(sp, suggestion)];
+                if let Some(add_lt_sugg) = add_lt_sugg {
+                    suggestions.push(add_lt_sugg);
+                }
+                err.multipart_suggestion_verbose(
+                    format!("{msg}..."),
+                    suggestions,
                     Applicability::MaybeIncorrect, // Issue #41966
                 );
             } else {
-                let consider = format!("{} `{}: {}`...", msg, bound_kind, sub,);
+                let consider = format!("{} `{}: {}`...", msg, bound_kind, sub);
                 err.help(&consider);
             }
         }
@@ -2423,7 +2537,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     };
                     let mut sugg =
                         vec![(sp, suggestion), (span.shrink_to_hi(), format!(" + {}", new_lt))];
-                    if let Some(lt) = add_lt_sugg {
+                    if let Some(lt) = add_lt_sugg.clone() {
                         sugg.push(lt);
                         sugg.rotate_right(1);
                     }
@@ -2529,7 +2643,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 // for the bound is not suitable for suggestions when `-Zverbose` is set because it
                 // uses `Debug` output, so we handle it specially here so that suggestions are
                 // always correct.
-                binding_suggestion(&mut err, type_param_span, bound_kind, name);
+                binding_suggestion(&mut err, type_param_span, bound_kind, name, None);
                 err
             }
 
@@ -2542,7 +2656,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "{} may not live long enough",
                     labeled_user_string
                 );
-                binding_suggestion(&mut err, type_param_span, bound_kind, "'static");
+                binding_suggestion(&mut err, type_param_span, bound_kind, "'static", None);
                 err
             }
 
@@ -2576,7 +2690,13 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                             new_binding_suggestion(&mut err, type_param_span);
                         }
                         _ => {
-                            binding_suggestion(&mut err, type_param_span, bound_kind, new_lt);
+                            binding_suggestion(
+                                &mut err,
+                                type_param_span,
+                                bound_kind,
+                                new_lt,
+                                add_lt_sugg,
+                            );
                         }
                     }
                 }
@@ -2755,7 +2875,7 @@ impl<'tcx> TypeRelation<'tcx> for SameTypeModuloInfer<'_, 'tcx> {
     where
         T: relate::Relate<'tcx>,
     {
-        Ok(ty::Binder::dummy(self.relate(a.skip_binder(), b.skip_binder())?))
+        Ok(a.rebind(self.relate(a.skip_binder(), b.skip_binder())?))
     }
 
     fn consts(
diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index e990fe7ecb50..baa97d72a4ba 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -4,6 +4,7 @@ use crate::errors::{
 };
 use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::infer::InferCtxt;
+use rustc_errors::IntoDiagnostic;
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, IntoDiagnosticArg};
 use rustc_hir as hir;
 use rustc_hir::def::Res;
@@ -15,10 +16,9 @@ use rustc_middle::hir::nested_filter;
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter, Print, Printer};
-use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst, SubstsRef};
 use rustc_middle::ty::{self, DefIdTree, InferConst};
+use rustc_middle::ty::{GenericArg, GenericArgKind, SubstsRef};
 use rustc_middle::ty::{IsSuggestable, Ty, TyCtxt, TypeckResults};
-use rustc_session::SessionDiagnostic;
 use rustc_span::symbol::{kw, Ident};
 use rustc_span::{BytePos, Span};
 use std::borrow::Cow;
@@ -199,7 +199,7 @@ fn ty_to_string<'tcx>(infcx: &InferCtxt<'_, 'tcx>, ty: Ty<'tcx>) -> String {
 }
 
 /// We don't want to directly use `ty_to_string` for closures as their type isn't really
-/// something users are familar with. Directly printing the `fn_sig` of closures also
+/// something users are familiar with. Directly printing the `fn_sig` of closures also
 /// doesn't work as they actually use the "rust-call" API.
 fn closure_as_fn_str<'tcx>(infcx: &InferCtxt<'_, 'tcx>, ty: Ty<'tcx>) -> String {
     let ty::Closure(_, substs) = ty.kind() else { unreachable!() };
@@ -341,7 +341,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 multi_suggestions,
                 bad_label,
             }
-            .into_diagnostic(&self.tcx.sess.parse_sess),
+            .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic),
             TypeAnnotationNeeded::E0283 => AmbigousImpl {
                 span,
                 source_kind,
@@ -351,7 +351,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 multi_suggestions,
                 bad_label,
             }
-            .into_diagnostic(&self.tcx.sess.parse_sess),
+            .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic),
             TypeAnnotationNeeded::E0284 => AmbigousReturn {
                 span,
                 source_kind,
@@ -361,7 +361,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 multi_suggestions,
                 bad_label,
             }
-            .into_diagnostic(&self.tcx.sess.parse_sess),
+            .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic),
         }
     }
 
@@ -511,20 +511,20 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     _ => "",
                 };
 
-                multi_suggestions.push(SourceKindMultiSuggestion::FullyQualified {
-                    span: receiver.span,
+                multi_suggestions.push(SourceKindMultiSuggestion::new_fully_qualified(
+                    receiver.span,
                     def_path,
                     adjustment,
                     successor,
-                });
+                ));
             }
             InferSourceKind::ClosureReturn { ty, data, should_wrap_expr } => {
                 let ty_info = ty_to_string(self, ty);
-                multi_suggestions.push(SourceKindMultiSuggestion::ClosureReturn {
+                multi_suggestions.push(SourceKindMultiSuggestion::new_closure_return(
                     ty_info,
                     data,
                     should_wrap_expr,
-                });
+                ));
             }
         }
         match error_code {
@@ -537,7 +537,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 multi_suggestions,
                 bad_label: None,
             }
-            .into_diagnostic(&self.tcx.sess.parse_sess),
+            .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic),
             TypeAnnotationNeeded::E0283 => AmbigousImpl {
                 span,
                 source_kind,
@@ -547,7 +547,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 multi_suggestions,
                 bad_label: None,
             }
-            .into_diagnostic(&self.tcx.sess.parse_sess),
+            .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic),
             TypeAnnotationNeeded::E0284 => AmbigousReturn {
                 span,
                 source_kind,
@@ -557,7 +557,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 multi_suggestions,
                 bad_label: None,
             }
-            .into_diagnostic(&self.tcx.sess.parse_sess),
+            .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic),
         }
     }
 
@@ -575,7 +575,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             span,
             generator_kind: GeneratorKindAsDiagArg(kind),
         }
-        .into_diagnostic(&self.tcx.sess.parse_sess)
+        .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic)
     }
 }
 
@@ -901,7 +901,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
                     }
                 }
             }
-            hir::ExprKind::MethodCall(segment, _, _) => {
+            hir::ExprKind::MethodCall(segment, ..) => {
                 if let Some(def_id) = self.typeck_results.type_dependent_def_id(expr.hir_id) {
                     let generics = tcx.generics_of(def_id);
                     let insertable: Option<_> = try {
@@ -909,7 +909,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
                             None?
                         }
                         let substs = self.node_substs_opt(expr.hir_id)?;
-                        let span = tcx.hir().span(segment.hir_id?);
+                        let span = tcx.hir().span(segment.hir_id);
                         let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
                         InsertableGenericArgs {
                             insert_span,
@@ -957,13 +957,13 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
         path.segments
             .iter()
             .filter_map(move |segment| {
-                let res = segment.res?;
+                let res = segment.res;
                 let generics_def_id = tcx.res_generics_def_id(res)?;
                 let generics = tcx.generics_of(generics_def_id);
                 if generics.has_impl_trait() {
                     return None;
                 }
-                let span = tcx.hir().span(segment.hir_id?);
+                let span = tcx.hir().span(segment.hir_id);
                 let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
                 Some(InsertableGenericArgs {
                     insert_span,
@@ -996,7 +996,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
                     if !segment.infer_args || generics.has_impl_trait() {
                         None?;
                     }
-                    let span = tcx.hir().span(segment.hir_id?);
+                    let span = tcx.hir().span(segment.hir_id);
                     let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
                     InsertableGenericArgs { insert_span, substs, generics_def_id: def_id, def_id }
                 };
@@ -1132,7 +1132,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindInferSourceVisitor<'a, 'tcx> {
                 let generic_args = &generics.own_substs_no_defaults(tcx, substs)
                     [generics.own_counts().lifetimes..];
                 let span = match expr.kind {
-                    ExprKind::MethodCall(path, _, _) => path.ident.span,
+                    ExprKind::MethodCall(path, ..) => path.ident.span,
                     _ => expr.span,
                 };
 
@@ -1181,7 +1181,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindInferSourceVisitor<'a, 'tcx> {
             })
             .any(|generics| generics.has_impl_trait())
         };
-        if let ExprKind::MethodCall(path, args, span) = expr.kind
+        if let ExprKind::MethodCall(path, receiver, args, span) = expr.kind
             && let Some(substs) = self.node_substs_opt(expr.hir_id)
             && substs.iter().any(|arg| self.generic_arg_contains_target(arg))
             && let Some(def_id) = self.typeck_results.type_dependent_def_id(expr.hir_id)
@@ -1189,12 +1189,12 @@ impl<'a, 'tcx> Visitor<'tcx> for FindInferSourceVisitor<'a, 'tcx> {
             && !has_impl_trait(def_id)
         {
             let successor =
-                args.get(1).map_or_else(|| (")", span.hi()), |arg| (", ", arg.span.lo()));
+                args.get(0).map_or_else(|| (")", span.hi()), |arg| (", ", arg.span.lo()));
             let substs = self.infcx.resolve_vars_if_possible(substs);
             self.update_infer_source(InferSource {
                 span: path.ident.span,
                 kind: InferSourceKind::FullyQualifiedMethodCall {
-                    receiver: args.first().unwrap(),
+                    receiver,
                     successor,
                     substs,
                     def_id,
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs
index 9a2ab3e32248..da0271a345e4 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs
@@ -1,6 +1,9 @@
 //! Error Reporting for Anonymous Region Lifetime Errors
 //! where both the regions are anonymous.
 
+use crate::errors::AddLifetimeParamsSuggestion;
+use crate::errors::LifetimeMismatch;
+use crate::errors::LifetimeMismatchLabels;
 use crate::infer::error_reporting::nice_region_error::find_anon_type::find_anon_type;
 use crate::infer::error_reporting::nice_region_error::util::AnonymousParamInfo;
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
@@ -8,11 +11,10 @@ use crate::infer::lexical_region_resolve::RegionResolutionError;
 use crate::infer::SubregionOrigin;
 use crate::infer::TyCtxt;
 
-use rustc_errors::{struct_span_err, Applicability, Diagnostic, ErrorGuaranteed};
-use rustc_hir as hir;
-use rustc_hir::{GenericParamKind, Ty};
+use rustc_errors::AddToDiagnostic;
+use rustc_errors::{Diagnostic, ErrorGuaranteed};
+use rustc_hir::Ty;
 use rustc_middle::ty::Region;
-use rustc_span::symbol::kw;
 
 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// Print the error message for lifetime errors when both the concerned regions are anonymous.
@@ -98,137 +100,50 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let sub_is_ret_type =
             self.is_return_type_anon(scope_def_id_sub, bregion_sub, ty_fndecl_sub);
 
-        let span_label_var1 = match anon_param_sup.pat.simple_ident() {
-            Some(simple_ident) => format!(" from `{}`", simple_ident),
-            None => String::new(),
-        };
-
-        let span_label_var2 = match anon_param_sub.pat.simple_ident() {
-            Some(simple_ident) => format!(" into `{}`", simple_ident),
-            None => String::new(),
-        };
-
         debug!(
             "try_report_anon_anon_conflict: sub_is_ret_type={:?} sup_is_ret_type={:?}",
             sub_is_ret_type, sup_is_ret_type
         );
 
-        let mut err = struct_span_err!(self.tcx().sess, span, E0623, "lifetime mismatch");
-
-        match (sup_is_ret_type, sub_is_ret_type) {
+        let labels = match (sup_is_ret_type, sub_is_ret_type) {
             (ret_capture @ Some(ret_span), _) | (_, ret_capture @ Some(ret_span)) => {
                 let param_span =
                     if sup_is_ret_type == ret_capture { ty_sub.span } else { ty_sup.span };
-
-                err.span_label(
+                LifetimeMismatchLabels::InRet {
                     param_span,
-                    "this parameter and the return type are declared with different lifetimes...",
-                );
-                err.span_label(ret_span, "");
-                err.span_label(span, format!("...but data{} is returned here", span_label_var1));
-            }
-
-            (None, None) => {
-                if ty_sup.hir_id == ty_sub.hir_id {
-                    err.span_label(ty_sup.span, "this type is declared with multiple lifetimes...");
-                    err.span_label(ty_sub.span, "");
-                    err.span_label(span, "...but data with one lifetime flows into the other here");
-                } else {
-                    err.span_label(
-                        ty_sup.span,
-                        "these two types are declared with different lifetimes...",
-                    );
-                    err.span_label(ty_sub.span, "");
-                    err.span_label(
-                        span,
-                        format!("...but data{} flows{} here", span_label_var1, span_label_var2),
-                    );
+                    ret_span,
+                    span,
+                    label_var1: anon_param_sup.pat.simple_ident(),
                 }
             }
-        }
 
-        if suggest_adding_lifetime_params(self.tcx(), sub, ty_sup, ty_sub, &mut err) {
-            err.note("each elided lifetime in input position becomes a distinct lifetime");
-        }
+            (None, None) => LifetimeMismatchLabels::Normal {
+                hir_equal: ty_sup.hir_id == ty_sub.hir_id,
+                ty_sup: ty_sup.span,
+                ty_sub: ty_sub.span,
+                span,
+                sup: anon_param_sup.pat.simple_ident(),
+                sub: anon_param_sub.pat.simple_ident(),
+            },
+        };
 
-        let reported = err.emit();
+        let suggestion =
+            AddLifetimeParamsSuggestion { tcx: self.tcx(), sub, ty_sup, ty_sub, add_note: true };
+        let err = LifetimeMismatch { span, labels, suggestion };
+        let reported = self.tcx().sess.emit_err(err);
         Some(reported)
     }
 }
 
+/// Currently only used in rustc_borrowck, probably should be
+/// removed in favour of public_errors::AddLifetimeParamsSuggestion
 pub fn suggest_adding_lifetime_params<'tcx>(
     tcx: TyCtxt<'tcx>,
     sub: Region<'tcx>,
-    ty_sup: &Ty<'_>,
-    ty_sub: &Ty<'_>,
+    ty_sup: &'tcx Ty<'_>,
+    ty_sub: &'tcx Ty<'_>,
     err: &mut Diagnostic,
-) -> bool {
-    let (
-        hir::Ty { kind: hir::TyKind::Rptr(lifetime_sub, _), .. },
-        hir::Ty { kind: hir::TyKind::Rptr(lifetime_sup, _), .. },
-    ) = (ty_sub, ty_sup) else {
-        return false;
-    };
-
-    if !lifetime_sub.name.is_anonymous() || !lifetime_sup.name.is_anonymous() {
-        return false;
-    };
-
-    let Some(anon_reg) = tcx.is_suitable_region(sub) else {
-        return false;
-    };
-
-    let hir_id = tcx.hir().local_def_id_to_hir_id(anon_reg.def_id);
-
-    let node = tcx.hir().get(hir_id);
-    let is_impl = matches!(&node, hir::Node::ImplItem(_));
-    let generics = match node {
-        hir::Node::Item(&hir::Item { kind: hir::ItemKind::Fn(_, ref generics, ..), .. })
-        | hir::Node::TraitItem(&hir::TraitItem { ref generics, .. })
-        | hir::Node::ImplItem(&hir::ImplItem { ref generics, .. }) => generics,
-        _ => return false,
-    };
-
-    let suggestion_param_name = generics
-        .params
-        .iter()
-        .filter(|p| matches!(p.kind, GenericParamKind::Lifetime { .. }))
-        .map(|p| p.name.ident().name)
-        .find(|i| *i != kw::UnderscoreLifetime);
-    let introduce_new = suggestion_param_name.is_none();
-    let suggestion_param_name =
-        suggestion_param_name.map(|n| n.to_string()).unwrap_or_else(|| "'a".to_owned());
-
-    debug!(?lifetime_sup.span);
-    debug!(?lifetime_sub.span);
-    let make_suggestion = |span: rustc_span::Span| {
-        if span.is_empty() {
-            (span, format!("{}, ", suggestion_param_name))
-        } else if let Ok("&") = tcx.sess.source_map().span_to_snippet(span).as_deref() {
-            (span.shrink_to_hi(), format!("{} ", suggestion_param_name))
-        } else {
-            (span, suggestion_param_name.clone())
-        }
-    };
-    let mut suggestions =
-        vec![make_suggestion(lifetime_sub.span), make_suggestion(lifetime_sup.span)];
-
-    if introduce_new {
-        let new_param_suggestion =
-            if let Some(first) = generics.params.iter().find(|p| !p.name.ident().span.is_empty()) {
-                (first.span.shrink_to_lo(), format!("{}, ", suggestion_param_name))
-            } else {
-                (generics.span, format!("<{}>", suggestion_param_name))
-            };
-
-        suggestions.push(new_param_suggestion);
-    }
-
-    let mut sugg = String::from("consider introducing a named lifetime parameter");
-    if is_impl {
-        sugg.push_str(" and update trait if needed");
-    }
-    err.multipart_suggestion(sugg, suggestions, Applicability::MaybeIncorrect);
-
-    true
+) {
+    let suggestion = AddLifetimeParamsSuggestion { tcx, sub, ty_sup, ty_sub, add_note: false };
+    suggestion.add_to_diagnostic(err);
 }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/find_anon_type.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/find_anon_type.rs
index ddad72fdab93..d8f540b74465 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/find_anon_type.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/find_anon_type.rs
@@ -91,7 +91,7 @@ impl<'tcx> Visitor<'tcx> for FindNestedTypeVisitor<'tcx> {
             hir::TyKind::TraitObject(bounds, ..) => {
                 for bound in bounds {
                     self.current_index.shift_in(1);
-                    self.visit_poly_trait_ref(bound, hir::TraitBoundModifier::None);
+                    self.visit_poly_trait_ref(bound);
                     self.current_index.shift_out(1);
                 }
             }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs
index c20b96cae2e4..1410e2b63b0b 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs
@@ -1,13 +1,14 @@
 //! Error Reporting for when the lifetime for a type doesn't match the `impl` selected for a predicate
 //! to hold.
 
+use crate::errors::{note_and_explain, IntroducesStaticBecauseUnmetLifetimeReq};
+use crate::errors::{ImplNote, MismatchedStaticLifetime, TraitSubdiag};
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
-use crate::infer::error_reporting::note_and_explain_region;
 use crate::infer::lexical_region_resolve::RegionResolutionError;
 use crate::infer::{SubregionOrigin, TypeTrace};
 use crate::traits::ObligationCauseCode;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan};
+use rustc_errors::{ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::intravisit::Visitor;
 use rustc_middle::ty::TypeVisitor;
@@ -39,12 +40,23 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             = *parent.code() else {
             return None;
         };
-        let mut err = self.tcx().sess.struct_span_err(cause.span, "incompatible lifetime on type");
+
         // FIXME: we should point at the lifetime
-        let mut multi_span: MultiSpan = vec![binding_span].into();
-        multi_span.push_span_label(binding_span, "introduces a `'static` lifetime requirement");
-        err.span_note(multi_span, "because this has an unmet lifetime requirement");
-        note_and_explain_region(self.tcx(), &mut err, "", sup, "...", Some(binding_span));
+        let multi_span: MultiSpan = vec![binding_span].into();
+        let multispan_subdiag = IntroducesStaticBecauseUnmetLifetimeReq {
+            unmet_requirements: multi_span,
+            binding_span,
+        };
+
+        let expl = note_and_explain::RegionExplanation::new(
+            self.tcx(),
+            sup,
+            Some(binding_span),
+            note_and_explain::PrefixKind::Empty,
+            note_and_explain::SuffixKind::Continues,
+        );
+        let mut impl_span = None;
+        let mut trait_subdiags = Vec::new();
         if let Some(impl_node) = self.tcx().hir().get_if_local(*impl_def_id) {
             // If an impl is local, then maybe this isn't what they want. Try to
             // be as helpful as possible with implicit lifetimes.
@@ -73,31 +85,30 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 // there aren't trait objects or because none are implicit, then just
                 // write a single note on the impl itself.
 
-                let impl_span = self.tcx().def_span(*impl_def_id);
-                err.span_note(impl_span, "...does not necessarily outlive the static lifetime introduced by the compatible `impl`");
+                impl_span = Some(self.tcx().def_span(*impl_def_id));
             } else {
                 // Otherwise, point at all implicit static lifetimes
 
-                err.note("...does not necessarily outlive the static lifetime introduced by the compatible `impl`");
                 for span in &traits {
-                    err.span_note(*span, "this has an implicit `'static` lifetime requirement");
+                    trait_subdiags.push(TraitSubdiag::Note { span: *span });
                     // It would be nice to put this immediately under the above note, but they get
                     // pushed to the end.
-                    err.span_suggestion_verbose(
-                        span.shrink_to_hi(),
-                        "consider relaxing the implicit `'static` requirement",
-                        " + '_",
-                        Applicability::MaybeIncorrect,
-                    );
+                    trait_subdiags.push(TraitSubdiag::Sugg { span: span.shrink_to_hi() });
                 }
             }
         } else {
             // Otherwise just point out the impl.
 
-            let impl_span = self.tcx().def_span(*impl_def_id);
-            err.span_note(impl_span, "...does not necessarily outlive the static lifetime introduced by the compatible `impl`");
+            impl_span = Some(self.tcx().def_span(*impl_def_id));
         }
-        let reported = err.emit();
+        let err = MismatchedStaticLifetime {
+            cause_span: cause.span,
+            unmet_lifetime_reqs: multispan_subdiag,
+            expl,
+            impl_note: ImplNote { impl_span },
+            trait_subdiags,
+        };
+        let reported = self.tcx().sess.emit_err(err);
         Some(reported)
     }
 }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
index f804569b0747..2ccfcd51b115 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
@@ -185,8 +185,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             | ObligationCauseCode::BlockTailExpression(hir_id) = cause.code()
             {
                 let parent_id = tcx.hir().get_parent_item(*hir_id);
-                let parent_id = tcx.hir().local_def_id_to_hir_id(parent_id);
-                if let Some(fn_decl) = tcx.hir().fn_decl_by_hir_id(parent_id) {
+                if let Some(fn_decl) = tcx.hir().fn_decl_by_hir_id(parent_id.into()) {
                     let mut span: MultiSpan = fn_decl.output.span().into();
                     let mut add_label = true;
                     if let hir::FnRetTy::Return(ty) = fn_decl.output {
@@ -300,7 +299,7 @@ pub fn suggest_new_region_bound(
             continue;
         }
         match fn_return.kind {
-            TyKind::OpaqueDef(item_id, _) => {
+            TyKind::OpaqueDef(item_id, _, _) => {
                 let item = tcx.hir().item(item_id);
                 let ItemKind::OpaqueTy(opaque) = &item.kind else {
                     return;
@@ -415,7 +414,8 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let tcx = self.tcx();
         match tcx.hir().get_if_local(def_id) {
             Some(Node::ImplItem(impl_item)) => {
-                match tcx.hir().find_by_def_id(tcx.hir().get_parent_item(impl_item.hir_id())) {
+                match tcx.hir().find_by_def_id(tcx.hir().get_parent_item(impl_item.hir_id()).def_id)
+                {
                     Some(Node::Item(Item {
                         kind: ItemKind::Impl(hir::Impl { self_ty, .. }),
                         ..
@@ -425,7 +425,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             }
             Some(Node::TraitItem(trait_item)) => {
                 let trait_did = tcx.hir().get_parent_item(trait_item.hir_id());
-                match tcx.hir().find_by_def_id(trait_did) {
+                match tcx.hir().find_by_def_id(trait_did.def_id) {
                     Some(Node::Item(Item { kind: ItemKind::Trait(..), .. })) => {
                         // The method being called is defined in the `trait`, but the `'static`
                         // obligation comes from the `impl`. Find that `impl` so that we can point
@@ -544,7 +544,7 @@ pub struct TraitObjectVisitor(pub FxHashSet<DefId>);
 impl<'tcx> TypeVisitor<'tcx> for TraitObjectVisitor {
     fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
         match t.kind() {
-            ty::Dynamic(preds, re) if re.is_static() => {
+            ty::Dynamic(preds, re, _) if re.is_static() => {
                 if let Some(def_id) = preds.principal_def_id() {
                     self.0.insert(def_id);
                 }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
index da465a764299..a6a39d062d51 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
@@ -154,16 +154,11 @@ impl<'tcx> Visitor<'tcx> for TypeParamSpanVisitor<'tcx> {
             }
             hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments {
                 [segment]
-                    if segment
-                        .res
-                        .map(|res| {
-                            matches!(
-                                res,
-                                Res::SelfTy { trait_: _, alias_to: _ }
-                                    | Res::Def(hir::def::DefKind::TyParam, _)
-                            )
-                        })
-                        .unwrap_or(false) =>
+                    if matches!(
+                        segment.res,
+                        Res::SelfTy { trait_: _, alias_to: _ }
+                            | Res::Def(hir::def::DefKind::TyParam, _)
+                    ) =>
                 {
                     self.types.push(path.span);
                 }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/note.rs b/compiler/rustc_infer/src/infer/error_reporting/note.rs
index cffdf56bb6d4..286cfb64a1ec 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/note.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/note.rs
@@ -2,7 +2,7 @@ use crate::errors::RegionOriginNote;
 use crate::infer::error_reporting::note_and_explain_region;
 use crate::infer::{self, InferCtxt, SubregionOrigin};
 use rustc_errors::{
-    fluent, struct_span_err, AddSubdiagnostic, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
+    fluent, struct_span_err, AddToDiagnostic, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
 };
 use rustc_middle::traits::ObligationCauseCode;
 use rustc_middle::ty::error::TypeError;
@@ -77,6 +77,13 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             infer::CheckAssociatedTypeBounds { ref parent, .. } => {
                 self.note_region_origin(err, &parent);
             }
+            infer::AscribeUserTypeProvePredicate(span) => {
+                RegionOriginNote::Plain {
+                    span,
+                    msg: fluent::infer::ascribe_user_type_prove_predicate,
+                }
+                .add_to_diagnostic(err);
+            }
         }
     }
 
@@ -356,6 +363,27 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
                 err
             }
+            infer::AscribeUserTypeProvePredicate(span) => {
+                let mut err =
+                    struct_span_err!(self.tcx.sess, span, E0478, "lifetime bound not satisfied");
+                note_and_explain_region(
+                    self.tcx,
+                    &mut err,
+                    "lifetime instantiated with ",
+                    sup,
+                    "",
+                    None,
+                );
+                note_and_explain_region(
+                    self.tcx,
+                    &mut err,
+                    "but lifetime must outlive ",
+                    sub,
+                    "",
+                    None,
+                );
+                err
+            }
         }
     }
 
diff --git a/compiler/rustc_infer/src/infer/freshen.rs b/compiler/rustc_infer/src/infer/freshen.rs
index 84004d2b21f9..fee15afc7b3a 100644
--- a/compiler/rustc_infer/src/infer/freshen.rs
+++ b/compiler/rustc_infer/src/infer/freshen.rs
@@ -126,7 +126,6 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
             | ty::ReFree(_)
             | ty::ReVar(_)
             | ty::RePlaceholder(..)
-            | ty::ReEmpty(_)
             | ty::ReErased => {
                 // replace all free regions with 'erased
                 self.tcx().lifetimes.re_erased
diff --git a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
index d0d9efe152cc..0ce271c0e5d6 100644
--- a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
+++ b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
@@ -69,7 +69,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// For more details visit the relevant sections of the [rustc dev guide].
     ///
     /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     pub fn replace_bound_vars_with_placeholders<T>(&self, binder: ty::Binder<'tcx, T>) -> T
     where
         T: TypeFoldable<'tcx> + Copy,
@@ -81,19 +81,19 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let next_universe = self.create_next_universe();
 
         let delegate = FnMutDelegate {
-            regions: |br: ty::BoundRegion| {
+            regions: &mut |br: ty::BoundRegion| {
                 self.tcx.mk_region(ty::RePlaceholder(ty::PlaceholderRegion {
                     universe: next_universe,
                     name: br.kind,
                 }))
             },
-            types: |bound_ty: ty::BoundTy| {
+            types: &mut |bound_ty: ty::BoundTy| {
                 self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
                     universe: next_universe,
                     name: bound_ty.var,
                 }))
             },
-            consts: |bound_var: ty::BoundVar, ty| {
+            consts: &mut |bound_var: ty::BoundVar, ty| {
                 self.tcx.mk_const(ty::ConstS {
                     kind: ty::ConstKind::Placeholder(ty::PlaceholderConst {
                         universe: next_universe,
@@ -104,9 +104,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             },
         };
 
-        let result = self.tcx.replace_bound_vars_uncached(binder, delegate);
-        debug!(?next_universe, ?result);
-        result
+        debug!(?next_universe);
+        self.tcx.replace_bound_vars_uncached(binder, delegate)
     }
 
     /// See [RegionConstraintCollector::leak_check][1].
diff --git a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
index 3783cfb4cc5c..5f13b2b3deb1 100644
--- a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
+++ b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
@@ -15,8 +15,9 @@ use rustc_data_structures::graph::implementation::{
 use rustc_data_structures::intern::Interned;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::ty::fold::TypeFoldable;
+use rustc_middle::ty::PlaceholderRegion;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_middle::ty::{ReEarlyBound, ReEmpty, ReErased, ReFree, ReStatic};
+use rustc_middle::ty::{ReEarlyBound, ReErased, ReFree, ReStatic};
 use rustc_middle::ty::{ReLateBound, RePlaceholder, ReVar};
 use rustc_middle::ty::{Region, RegionVid};
 use rustc_span::Span;
@@ -51,6 +52,13 @@ pub struct LexicalRegionResolutions<'tcx> {
 
 #[derive(Copy, Clone, Debug)]
 pub(crate) enum VarValue<'tcx> {
+    /// Empty lifetime is for data that is never accessed.  We tag the
+    /// empty lifetime with a universe -- the idea is that we don't
+    /// want `exists<'a> { forall<'b> { 'b: 'a } }` to be satisfiable.
+    /// Therefore, the `'empty` in a universe `U` is less than all
+    /// regions visible from `U`, but not less than regions not visible
+    /// from `U`.
+    Empty(ty::UniverseIndex),
     Value(Region<'tcx>),
     ErrorValue,
 }
@@ -117,7 +125,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         &mut self,
         errors: &mut Vec<RegionResolutionError<'tcx>>,
     ) -> LexicalRegionResolutions<'tcx> {
-        let mut var_data = self.construct_var_data(self.tcx());
+        let mut var_data = self.construct_var_data();
 
         if cfg!(debug_assertions) {
             self.dump_constraints();
@@ -137,13 +145,12 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
 
     /// Initially, the value for all variables is set to `'empty`, the
     /// empty region. The `expansion` phase will grow this larger.
-    fn construct_var_data(&self, tcx: TyCtxt<'tcx>) -> LexicalRegionResolutions<'tcx> {
+    fn construct_var_data(&self) -> LexicalRegionResolutions<'tcx> {
         LexicalRegionResolutions {
             values: IndexVec::from_fn_n(
                 |vid| {
                     let vid_universe = self.var_infos[vid].universe;
-                    let re_empty = tcx.mk_region(ty::ReEmpty(vid_universe));
-                    VarValue::Value(re_empty)
+                    VarValue::Empty(vid_universe)
                 },
                 self.num_vars(),
             ),
@@ -189,20 +196,131 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         }
     }
 
+    /// Gets the LUb of a given region and the empty region
+    fn lub_empty(&self, a_region: Region<'tcx>) -> Result<Region<'tcx>, PlaceholderRegion> {
+        match *a_region {
+            ReLateBound(..) | ReErased => {
+                bug!("cannot relate region: {:?}", a_region);
+            }
+
+            ReVar(v_id) => {
+                span_bug!(
+                    self.var_infos[v_id].origin.span(),
+                    "lub invoked with non-concrete regions: {:?}",
+                    a_region,
+                );
+            }
+
+            ReStatic => {
+                // nothing lives longer than `'static`
+                Ok(self.tcx().lifetimes.re_static)
+            }
+
+            ReEarlyBound(_) | ReFree(_) => {
+                // All empty regions are less than early-bound, free,
+                // and scope regions.
+                Ok(a_region)
+            }
+
+            RePlaceholder(placeholder) => Err(placeholder),
+        }
+    }
+
     fn expansion(&self, var_values: &mut LexicalRegionResolutions<'tcx>) {
+        // In the first pass, we expand region vids according to constraints we
+        // have previously found. In the second pass, we loop through the region
+        // vids we expanded and expand *across* region vids (effectively
+        // "expanding" new `RegSubVar` constraints).
+
+        // Tracks the `VarSubVar` constraints generated for each region vid. We
+        // later use this to expand across vids.
         let mut constraints = IndexVec::from_elem_n(Vec::new(), var_values.values.len());
+        // Tracks the changed region vids.
         let mut changes = Vec::new();
         for constraint in self.data.constraints.keys() {
-            let (a_vid, a_region, b_vid, b_data) = match *constraint {
+            match *constraint {
                 Constraint::RegSubVar(a_region, b_vid) => {
                     let b_data = var_values.value_mut(b_vid);
-                    (None, a_region, b_vid, b_data)
+
+                    if self.expand_node(a_region, b_vid, b_data) {
+                        changes.push(b_vid);
+                    }
                 }
                 Constraint::VarSubVar(a_vid, b_vid) => match *var_values.value(a_vid) {
                     VarValue::ErrorValue => continue,
+                    VarValue::Empty(a_universe) => {
+                        let b_data = var_values.value_mut(b_vid);
+
+                        let changed = (|| match *b_data {
+                            VarValue::Empty(b_universe) => {
+                                // Empty regions are ordered according to the universe
+                                // they are associated with.
+                                let ui = a_universe.min(b_universe);
+
+                                debug!(
+                                    "Expanding value of {:?} \
+                                    from empty lifetime with universe {:?} \
+                                    to empty lifetime with universe {:?}",
+                                    b_vid, b_universe, ui
+                                );
+
+                                *b_data = VarValue::Empty(ui);
+                                true
+                            }
+                            VarValue::Value(cur_region) => {
+                                let lub = match self.lub_empty(cur_region) {
+                                    Ok(r) => r,
+                                    // If the empty and placeholder regions are in the same universe,
+                                    // then the LUB is the Placeholder region (which is the cur_region).
+                                    // If they are not in the same universe, the LUB is the Static lifetime.
+                                    Err(placeholder) if a_universe == placeholder.universe => {
+                                        cur_region
+                                    }
+                                    Err(_) => self.tcx().lifetimes.re_static,
+                                };
+
+                                if lub == cur_region {
+                                    return false;
+                                }
+
+                                debug!(
+                                    "Expanding value of {:?} from {:?} to {:?}",
+                                    b_vid, cur_region, lub
+                                );
+
+                                *b_data = VarValue::Value(lub);
+                                true
+                            }
+
+                            VarValue::ErrorValue => false,
+                        })();
+
+                        if changed {
+                            changes.push(b_vid);
+                        }
+                        match b_data {
+                            VarValue::Value(Region(Interned(ReStatic, _)))
+                            | VarValue::ErrorValue => (),
+                            _ => {
+                                constraints[a_vid].push((a_vid, b_vid));
+                                constraints[b_vid].push((a_vid, b_vid));
+                            }
+                        }
+                    }
                     VarValue::Value(a_region) => {
                         let b_data = var_values.value_mut(b_vid);
-                        (Some(a_vid), a_region, b_vid, b_data)
+
+                        if self.expand_node(a_region, b_vid, b_data) {
+                            changes.push(b_vid);
+                        }
+                        match b_data {
+                            VarValue::Value(Region(Interned(ReStatic, _)))
+                            | VarValue::ErrorValue => (),
+                            _ => {
+                                constraints[a_vid].push((a_vid, b_vid));
+                                constraints[b_vid].push((a_vid, b_vid));
+                            }
+                        }
                     }
                 },
                 Constraint::RegSubReg(..) | Constraint::VarSubReg(..) => {
@@ -210,18 +328,6 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                     // is done, in `collect_errors`.
                     continue;
                 }
-            };
-            if self.expand_node(a_region, b_vid, b_data) {
-                changes.push(b_vid);
-            }
-            if let Some(a_vid) = a_vid {
-                match b_data {
-                    VarValue::Value(Region(Interned(ReStatic, _))) | VarValue::ErrorValue => (),
-                    _ => {
-                        constraints[a_vid].push((a_vid, b_vid));
-                        constraints[b_vid].push((a_vid, b_vid));
-                    }
-                }
             }
         }
 
@@ -242,6 +348,10 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         }
     }
 
+    /// Expands the value of the region represented with `b_vid` with current
+    /// value `b_data` to the lub of `b_data` and `a_region`. The corresponds
+    /// with the constraint `'?b: 'a` (`'a <: '?b`), where `'a` is some known
+    /// region and `'?b` is some region variable.
     fn expand_node(
         &self,
         a_region: Region<'tcx>,
@@ -263,14 +373,28 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         }
 
         match *b_data {
+            VarValue::Empty(empty_ui) => {
+                let lub = match self.lub_empty(a_region) {
+                    Ok(r) => r,
+                    // If this empty region is from a universe that can
+                    // name the placeholder, then the placeholder is
+                    // larger; otherwise, the only ancestor is `'static`.
+                    Err(placeholder) if empty_ui.can_name(placeholder.universe) => {
+                        self.tcx().mk_region(RePlaceholder(placeholder))
+                    }
+                    Err(_) => self.tcx().lifetimes.re_static,
+                };
+
+                debug!("Expanding value of {:?} from empty lifetime to {:?}", b_vid, lub);
+
+                *b_data = VarValue::Value(lub);
+                true
+            }
             VarValue::Value(cur_region) => {
                 // This is a specialized version of the `lub_concrete_regions`
                 // check below for a common case, here purely as an
                 // optimization.
                 let b_universe = self.var_infos[b_vid].universe;
-                if let ReEmpty(a_universe) = *a_region && a_universe == b_universe {
-                    return false;
-                }
 
                 let mut lub = self.lub_concrete_regions(a_region, cur_region);
                 if lub == cur_region {
@@ -300,6 +424,78 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         }
     }
 
+    /// True if `a <= b`.
+    fn sub_region_values(&self, a: VarValue<'tcx>, b: VarValue<'tcx>) -> bool {
+        match (a, b) {
+            // Error region is `'static`
+            (VarValue::ErrorValue, _) | (_, VarValue::ErrorValue) => return true,
+            (VarValue::Empty(a_ui), VarValue::Empty(b_ui)) => {
+                // Empty regions are ordered according to the universe
+                // they are associated with.
+                a_ui.min(b_ui) == b_ui
+            }
+            (VarValue::Value(a), VarValue::Empty(_)) => {
+                match *a {
+                    ReLateBound(..) | ReErased => {
+                        bug!("cannot relate region: {:?}", a);
+                    }
+
+                    ReVar(v_id) => {
+                        span_bug!(
+                            self.var_infos[v_id].origin.span(),
+                            "lub_concrete_regions invoked with non-concrete region: {:?}",
+                            a
+                        );
+                    }
+
+                    ReStatic | ReEarlyBound(_) | ReFree(_) => {
+                        // nothing lives longer than `'static`
+
+                        // All empty regions are less than early-bound, free,
+                        // and scope regions.
+
+                        false
+                    }
+
+                    RePlaceholder(_) => {
+                        // The LUB is either `a` or `'static`
+                        false
+                    }
+                }
+            }
+            (VarValue::Empty(a_ui), VarValue::Value(b)) => {
+                match *b {
+                    ReLateBound(..) | ReErased => {
+                        bug!("cannot relate region: {:?}", b);
+                    }
+
+                    ReVar(v_id) => {
+                        span_bug!(
+                            self.var_infos[v_id].origin.span(),
+                            "lub_concrete_regions invoked with non-concrete regions: {:?}",
+                            b
+                        );
+                    }
+
+                    ReStatic | ReEarlyBound(_) | ReFree(_) => {
+                        // nothing lives longer than `'static`
+                        // All empty regions are less than early-bound, free,
+                        // and scope regions.
+                        true
+                    }
+
+                    RePlaceholder(placeholder) => {
+                        // If this empty region is from a universe that can
+                        // name the placeholder, then the placeholder is
+                        // larger; otherwise, the only ancestor is `'static`.
+                        if a_ui.can_name(placeholder.universe) { true } else { false }
+                    }
+                }
+            }
+            (VarValue::Value(a), VarValue::Value(b)) => self.sub_concrete_regions(a, b),
+        }
+    }
+
     /// True if `a <= b`, but not defined over inference variables.
     #[instrument(level = "trace", skip(self))]
     fn sub_concrete_regions(&self, a: Region<'tcx>, b: Region<'tcx>) -> bool {
@@ -333,9 +529,9 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
     ///
     /// Neither `a` nor `b` may be an inference variable (hence the
     /// term "concrete regions").
-    #[instrument(level = "trace", skip(self))]
+    #[instrument(level = "trace", skip(self), ret)]
     fn lub_concrete_regions(&self, a: Region<'tcx>, b: Region<'tcx>) -> Region<'tcx> {
-        let r = match (*a, *b) {
+        match (*a, *b) {
             (ReLateBound(..), _) | (_, ReLateBound(..)) | (ReErased, _) | (_, ReErased) => {
                 bug!("cannot relate region: LUB({:?}, {:?})", a, b);
             }
@@ -355,37 +551,6 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                 self.tcx().lifetimes.re_static
             }
 
-            (ReEmpty(_), ReEarlyBound(_) | ReFree(_)) => {
-                // All empty regions are less than early-bound, free,
-                // and scope regions.
-                b
-            }
-
-            (ReEarlyBound(_) | ReFree(_), ReEmpty(_)) => {
-                // All empty regions are less than early-bound, free,
-                // and scope regions.
-                a
-            }
-
-            (ReEmpty(a_ui), ReEmpty(b_ui)) => {
-                // Empty regions are ordered according to the universe
-                // they are associated with.
-                let ui = a_ui.min(b_ui);
-                self.tcx().mk_region(ReEmpty(ui))
-            }
-
-            (ReEmpty(empty_ui), RePlaceholder(placeholder))
-            | (RePlaceholder(placeholder), ReEmpty(empty_ui)) => {
-                // If this empty region is from a universe that can
-                // name the placeholder, then the placeholder is
-                // larger; otherwise, the only ancestor is `'static`.
-                if empty_ui.can_name(placeholder.universe) {
-                    self.tcx().mk_region(RePlaceholder(placeholder))
-                } else {
-                    self.tcx().lifetimes.re_static
-                }
-            }
-
             (ReEarlyBound(_) | ReFree(_), ReEarlyBound(_) | ReFree(_)) => {
                 self.region_rels.lub_free_regions(a, b)
             }
@@ -399,11 +564,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                     self.tcx().lifetimes.re_static
                 }
             }
-        };
-
-        debug!("lub_concrete_regions({:?}, {:?}) = {:?}", a, b, r);
-
-        r
+        }
     }
 
     /// After expansion is complete, go and check upper bounds (i.e.,
@@ -512,7 +673,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
 
         for (node_vid, value) in var_data.values.iter_enumerated() {
             match *value {
-                VarValue::Value(_) => { /* Inference successful */ }
+                VarValue::Empty(_) | VarValue::Value(_) => { /* Inference successful */ }
                 VarValue::ErrorValue => {
                     // Inference impossible: this value contains
                     // inconsistent constraints.
@@ -833,12 +994,25 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
             }
 
             VerifyBound::OutlivedBy(r) => {
-                self.sub_concrete_regions(min, var_values.normalize(self.tcx(), *r))
+                let a = match *min {
+                    ty::ReVar(rid) => var_values.values[rid],
+                    _ => VarValue::Value(min),
+                };
+                let b = match **r {
+                    ty::ReVar(rid) => var_values.values[rid],
+                    _ => VarValue::Value(*r),
+                };
+                self.sub_region_values(a, b)
             }
 
-            VerifyBound::IsEmpty => {
-                matches!(*min, ty::ReEmpty(_))
-            }
+            VerifyBound::IsEmpty => match *min {
+                ty::ReVar(rid) => match var_values.values[rid] {
+                    VarValue::ErrorValue => false,
+                    VarValue::Empty(_) => true,
+                    VarValue::Value(_) => false,
+                },
+                _ => false,
+            },
 
             VerifyBound::AnyBound(bs) => {
                 bs.iter().any(|b| self.bound_is_met(b, var_values, generic_ty, min))
@@ -880,6 +1054,7 @@ impl<'tcx> LexicalRegionResolutions<'tcx> {
     ) -> ty::Region<'tcx> {
         let result = match *r {
             ty::ReVar(rid) => match self.values[rid] {
+                VarValue::Empty(_) => r,
                 VarValue::Value(r) => r,
                 VarValue::ErrorValue => tcx.lifetimes.re_static,
             },
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index 60ebf8b949d2..efc9c1ca46fe 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -16,10 +16,12 @@ use rustc_data_structures::undo_log::Rollback;
 use rustc_data_structures::unify as ut;
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
 use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::hir_id::OwnerId;
 use rustc_middle::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc_middle::infer::unify_key::{ConstVarValue, ConstVariableValue};
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind, ToType};
 use rustc_middle::mir::interpret::{ErrorHandled, EvalToValTreeResult};
+use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::traits::select;
 use rustc_middle::ty::abstract_const::{AbstractConst, FailureKind};
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -353,12 +355,11 @@ pub enum ValuePairs<'tcx> {
 
 impl<'tcx> ValuePairs<'tcx> {
     pub fn ty(&self) -> Option<(Ty<'tcx>, Ty<'tcx>)> {
-        if let ValuePairs::Terms(ExpectedFound {
-            expected: ty::Term::Ty(expected),
-            found: ty::Term::Ty(found),
-        }) = self
+        if let ValuePairs::Terms(ExpectedFound { expected, found }) = self
+            && let Some(expected) = expected.ty()
+            && let Some(found) = found.ty()
         {
-            Some((*expected, *found))
+            Some((expected, found))
         } else {
             None
         }
@@ -409,7 +410,11 @@ pub enum SubregionOrigin<'tcx> {
 
     /// Comparing the signature and requirements of an impl method against
     /// the containing trait.
-    CompareImplItemObligation { span: Span, impl_item_def_id: LocalDefId, trait_item_def_id: DefId },
+    CompareImplItemObligation {
+        span: Span,
+        impl_item_def_id: LocalDefId,
+        trait_item_def_id: DefId,
+    },
 
     /// Checking that the bounds of a trait's associated type hold for a given impl
     CheckAssociatedTypeBounds {
@@ -417,12 +422,24 @@ pub enum SubregionOrigin<'tcx> {
         impl_item_def_id: LocalDefId,
         trait_item_def_id: DefId,
     },
+
+    AscribeUserTypeProvePredicate(Span),
 }
 
 // `SubregionOrigin` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 static_assert_size!(SubregionOrigin<'_>, 32);
 
+impl<'tcx> SubregionOrigin<'tcx> {
+    pub fn to_constraint_category(&self) -> ConstraintCategory<'tcx> {
+        match self {
+            Self::Subtype(type_trace) => type_trace.cause.to_constraint_category(),
+            Self::AscribeUserTypeProvePredicate(span) => ConstraintCategory::Predicate(*span),
+            _ => ConstraintCategory::BoringNoLocation,
+        }
+    }
+}
+
 /// Times when we replace late-bound regions with variables:
 #[derive(Clone, Copy, Debug)]
 pub enum LateBoundRegionConversionTime {
@@ -567,9 +584,9 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
     /// Used only by `rustc_typeck` during body type-checking/inference,
     /// will initialize `in_progress_typeck_results` with fresh `TypeckResults`.
     /// Will also change the scope for opaque type defining use checks to the given owner.
-    pub fn with_fresh_in_progress_typeck_results(mut self, table_owner: LocalDefId) -> Self {
+    pub fn with_fresh_in_progress_typeck_results(mut self, table_owner: OwnerId) -> Self {
         self.fresh_typeck_results = Some(RefCell::new(ty::TypeckResults::new(table_owner)));
-        self.with_opaque_type_inference(DefiningAnchor::Bind(table_owner))
+        self.with_opaque_type_inference(DefiningAnchor::Bind(table_owner.def_id))
     }
 
     /// Whenever the `InferCtxt` should be able to handle defining uses of opaque types,
@@ -689,8 +706,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     #[instrument(skip(self), level = "debug")]
     pub fn try_unify_abstract_consts(
         &self,
-        a: ty::Unevaluated<'tcx, ()>,
-        b: ty::Unevaluated<'tcx, ()>,
+        a: ty::UnevaluatedConst<'tcx>,
+        b: ty::UnevaluatedConst<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> bool {
         // Reject any attempt to unify two unevaluated constants that contain inference
@@ -1006,7 +1023,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         predicate: ty::PolyCoercePredicate<'tcx>,
-    ) -> Option<InferResult<'tcx, ()>> {
+    ) -> Result<InferResult<'tcx, ()>, (TyVid, TyVid)> {
         let subtype_predicate = predicate.map_bound(|p| ty::SubtypePredicate {
             a_is_expected: false, // when coercing from `a` to `b`, `b` is expected
             a: p.a,
@@ -1020,7 +1037,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         predicate: ty::PolySubtypePredicate<'tcx>,
-    ) -> Option<InferResult<'tcx, ()>> {
+    ) -> Result<InferResult<'tcx, ()>, (TyVid, TyVid)> {
         // Check for two unresolved inference variables, in which case we can
         // make no progress. This is partly a micro-optimization, but it's
         // also an opportunity to "sub-unify" the variables. This isn't
@@ -1039,12 +1056,12 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         match (r_a.kind(), r_b.kind()) {
             (&ty::Infer(ty::TyVar(a_vid)), &ty::Infer(ty::TyVar(b_vid))) => {
                 self.inner.borrow_mut().type_variables().sub(a_vid, b_vid);
-                return None;
+                return Err((a_vid, b_vid));
             }
             _ => {}
         }
 
-        Some(self.commit_if_ok(|_snapshot| {
+        Ok(self.commit_if_ok(|_snapshot| {
             let ty::SubtypePredicate { a_is_expected, a, b } =
                 self.replace_bound_vars_with_placeholders(predicate);
 
@@ -1333,7 +1350,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// `resolve_vars_if_possible` as well as `fully_resolve`.
     ///
     /// Make sure to call [`InferCtxt::process_registered_region_obligations`]
-    /// first, or preferrably use [`InferCtxt::check_region_obligations_and_report_errors`]
+    /// first, or preferably use [`InferCtxt::check_region_obligations_and_report_errors`]
     /// to do both of these operations together.
     pub fn resolve_regions_and_report_errors(
         &self,
@@ -1674,7 +1691,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn try_const_eval_resolve(
         &self,
         param_env: ty::ParamEnv<'tcx>,
-        unevaluated: ty::Unevaluated<'tcx>,
+        unevaluated: ty::UnevaluatedConst<'tcx>,
         ty: Ty<'tcx>,
         span: Option<Span>,
     ) -> Result<ty::Const<'tcx>, ErrorHandled> {
@@ -1709,7 +1726,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn const_eval_resolve(
         &self,
         mut param_env: ty::ParamEnv<'tcx>,
-        unevaluated: ty::Unevaluated<'tcx>,
+        unevaluated: ty::UnevaluatedConst<'tcx>,
         span: Option<Span>,
     ) -> EvalToValTreeResult<'tcx> {
         let mut substs = self.resolve_vars_if_possible(unevaluated.substs);
@@ -1718,7 +1735,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         // Postpone the evaluation of constants whose substs depend on inference
         // variables
         if substs.has_infer_types_or_consts() {
-            let ac = AbstractConst::new(self.tcx, unevaluated.shrink());
+            let ac = AbstractConst::new(self.tcx, unevaluated);
             match ac {
                 Ok(None) => {
                     substs = InternalSubsts::identity_for_item(self.tcx, unevaluated.def.did);
@@ -1740,11 +1757,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         debug!(?param_env_erased);
         debug!(?substs_erased);
 
-        let unevaluated = ty::Unevaluated {
-            def: unevaluated.def,
-            substs: substs_erased,
-            promoted: unevaluated.promoted,
-        };
+        let unevaluated = ty::UnevaluatedConst { def: unevaluated.def, substs: substs_erased };
 
         // The return value is the evaluated value which doesn't contain any reference to inference
         // variables, thus we don't need to substitute back the original values.
@@ -1832,7 +1845,7 @@ impl<'tcx> TyOrConstInferVar<'tcx> {
 
     /// Tries to extract an inference variable from a type, returns `None`
     /// for types other than `ty::Infer(_)` (or `InferTy::Fresh*`).
-    pub fn maybe_from_ty(ty: Ty<'tcx>) -> Option<Self> {
+    fn maybe_from_ty(ty: Ty<'tcx>) -> Option<Self> {
         match *ty.kind() {
             ty::Infer(ty::TyVar(v)) => Some(TyOrConstInferVar::Ty(v)),
             ty::Infer(ty::IntVar(v)) => Some(TyOrConstInferVar::TyInt(v)),
@@ -1843,7 +1856,7 @@ impl<'tcx> TyOrConstInferVar<'tcx> {
 
     /// Tries to extract an inference variable from a constant, returns `None`
     /// for constants other than `ty::ConstKind::Infer(_)` (or `InferConst::Fresh`).
-    pub fn maybe_from_const(ct: ty::Const<'tcx>) -> Option<Self> {
+    fn maybe_from_const(ct: ty::Const<'tcx>) -> Option<Self> {
         match ct.kind() {
             ty::ConstKind::Infer(InferConst::Var(v)) => Some(TyOrConstInferVar::Const(v)),
             _ => None,
@@ -1992,6 +2005,7 @@ impl<'tcx> SubregionOrigin<'tcx> {
             DataBorrowed(_, a) => a,
             ReferenceOutlivesReferent(_, a) => a,
             CompareImplItemObligation { span, .. } => span,
+            AscribeUserTypeProvePredicate(span) => span,
             CheckAssociatedTypeBounds { ref parent, .. } => parent.span(),
         }
     }
@@ -2024,6 +2038,10 @@ impl<'tcx> SubregionOrigin<'tcx> {
                 parent: Box::new(default()),
             },
 
+            traits::ObligationCauseCode::AscribeUserTypeProvePredicate(span) => {
+                SubregionOrigin::AscribeUserTypeProvePredicate(span)
+            }
+
             _ => default(),
         }
     }
diff --git a/compiler/rustc_infer/src/infer/nll_relate/mod.rs b/compiler/rustc_infer/src/infer/nll_relate/mod.rs
index e7e93116a66d..bb6f6ae60e26 100644
--- a/compiler/rustc_infer/src/infer/nll_relate/mod.rs
+++ b/compiler/rustc_infer/src/infer/nll_relate/mod.rs
@@ -542,7 +542,7 @@ where
         true
     }
 
-    #[instrument(skip(self, info), level = "trace")]
+    #[instrument(skip(self, info), level = "trace", ret)]
     fn relate_with_variance<T: Relate<'tcx>>(
         &mut self,
         variance: ty::Variance,
@@ -560,8 +560,6 @@ where
 
         self.ambient_variance = old_ambient_variance;
 
-        debug!(?r);
-
         Ok(r)
     }
 
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs
index 233a5004a393..9bf92f08aa54 100644
--- a/compiler/rustc_infer/src/infer/opaque_types.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types.rs
@@ -7,8 +7,9 @@ use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::vec_map::VecMap;
 use rustc_hir as hir;
 use rustc_middle::traits::ObligationCause;
+use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::fold::BottomUpFolder;
-use rustc_middle::ty::subst::{GenericArgKind, Subst};
+use rustc_middle::ty::GenericArgKind;
 use rustc_middle::ty::{
     self, OpaqueHiddenType, OpaqueTypeKey, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
     TypeVisitable, TypeVisitor,
@@ -73,7 +74,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     // for opaque types, and then use that kind to fix the spans for type errors
                     // that we see later on.
                     let ty_var = self.next_ty_var(TypeVariableOrigin {
-                        kind: TypeVariableOriginKind::TypeInference,
+                        kind: TypeVariableOriginKind::OpaqueTypeInference(def_id),
                         span,
                     });
                     obligations.extend(
@@ -176,16 +177,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         } else if let Some(res) = process(b, a) {
             res
         } else {
-            // Rerun equality check, but this time error out due to
-            // different types.
-            match self.at(cause, param_env).define_opaque_types(false).eq(a, b) {
-                Ok(_) => span_bug!(
-                    cause.span,
-                    "opaque types are never equal to anything but themselves: {:#?}",
-                    (a.kind(), b.kind())
-                ),
-                Err(e) => Err(e),
-            }
+            let (a, b) = self.resolve_vars_if_possible((a, b));
+            Err(TypeError::Sorts(ExpectedFound::new(true, a, b)))
         }
     }
 
@@ -390,7 +383,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         });
     }
 
-    #[instrument(skip(self), level = "trace")]
+    #[instrument(skip(self), level = "trace", ret)]
     pub fn opaque_type_origin(&self, def_id: LocalDefId, span: Span) -> Option<OpaqueTyOrigin> {
         let opaque_hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
         let parent_def_id = match self.defining_use_anchor {
@@ -421,16 +414,14 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         in_definition_scope.then_some(*origin)
     }
 
-    #[instrument(skip(self), level = "trace")]
+    #[instrument(skip(self), level = "trace", ret)]
     fn opaque_ty_origin_unchecked(&self, def_id: LocalDefId, span: Span) -> OpaqueTyOrigin {
-        let origin = match self.tcx.hir().expect_item(def_id).kind {
+        match self.tcx.hir().expect_item(def_id).kind {
             hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => origin,
             ref itemkind => {
                 span_bug!(span, "weird opaque type: {:?}, {:#?}", def_id, itemkind)
             }
-        };
-        trace!(?origin);
-        origin
+        }
     }
 }
 
@@ -625,7 +616,7 @@ fn may_define_opaque_type(tcx: TyCtxt<'_>, def_id: LocalDefId, opaque_hir_id: hi
     let scope = tcx.hir().get_defining_scope(opaque_hir_id);
     // We walk up the node tree until we hit the root or the scope of the opaque type.
     while hir_id != scope && hir_id != hir::CRATE_HIR_ID {
-        hir_id = tcx.hir().local_def_id_to_hir_id(tcx.hir().get_parent_item(hir_id));
+        hir_id = tcx.hir().get_parent_item(hir_id).into();
     }
     // Syntactically, we are allowed to define the concrete type if:
     let res = hir_id == scope;
diff --git a/compiler/rustc_infer/src/infer/opaque_types/table.rs b/compiler/rustc_infer/src/infer/opaque_types/table.rs
index fb12da0cc13f..4d124554afb9 100644
--- a/compiler/rustc_infer/src/infer/opaque_types/table.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types/table.rs
@@ -29,7 +29,7 @@ impl<'tcx> OpaqueTypeStorage<'tcx> {
         }
     }
 
-    #[instrument(level = "debug")]
+    #[instrument(level = "debug", ret)]
     pub fn take_opaque_types(&mut self) -> OpaqueTypeMap<'tcx> {
         std::mem::take(&mut self.opaque_types)
     }
diff --git a/compiler/rustc_infer/src/infer/outlives/components.rs b/compiler/rustc_infer/src/infer/outlives/components.rs
index b2d7f4a663ae..14ee9f051901 100644
--- a/compiler/rustc_infer/src/infer/outlives/components.rs
+++ b/compiler/rustc_infer/src/infer/outlives/components.rs
@@ -3,8 +3,9 @@
 // RFC for reference.
 
 use rustc_data_structures::sso::SsoHashSet;
+use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, SubstsRef, Ty, TyCtxt, TypeVisitable};
 use smallvec::{smallvec, SmallVec};
 
 #[derive(Debug)]
@@ -45,6 +46,8 @@ pub enum Component<'tcx> {
     // them. This gives us room to improve the regionck reasoning in
     // the future without breaking backwards compat.
     EscapingProjection(Vec<Component<'tcx>>),
+
+    Opaque(DefId, SubstsRef<'tcx>),
 }
 
 /// Push onto `out` all the things that must outlive `'a` for the condition
@@ -120,6 +123,17 @@ fn compute_components<'tcx>(
                 out.push(Component::Param(p));
             }
 
+            // Ignore lifetimes found in opaque types. Opaque types can
+            // have lifetimes in their substs which their hidden type doesn't
+            // actually use. If we inferred that an opaque type is outlived by
+            // its parameter lifetimes, then we could prove that any lifetime
+            // outlives any other lifetime, which is unsound.
+            // See https://github.com/rust-lang/rust/issues/84305 for
+            // more details.
+            ty::Opaque(def_id, substs) => {
+                out.push(Component::Opaque(def_id, substs));
+            },
+
             // For projections, we prefer to generate an obligation like
             // `<P0 as Trait<P1...Pn>>::Foo: 'a`, because this gives the
             // regionck more ways to prove that it holds. However,
@@ -168,7 +182,6 @@ fn compute_components<'tcx>(
             ty::Float(..) |       // OutlivesScalar
             ty::Never |           // ...
             ty::Adt(..) |         // OutlivesNominalType
-            ty::Opaque(..) |      // OutlivesNominalType (ish)
             ty::Foreign(..) |     // OutlivesNominalType
             ty::Str |             // OutlivesScalar (ish)
             ty::Slice(..) |       // ...
diff --git a/compiler/rustc_infer/src/infer/outlives/env.rs b/compiler/rustc_infer/src/infer/outlives/env.rs
index 872886da3626..113d4f090667 100644
--- a/compiler/rustc_infer/src/infer/outlives/env.rs
+++ b/compiler/rustc_infer/src/infer/outlives/env.rs
@@ -53,6 +53,7 @@ pub struct OutlivesEnvironment<'tcx> {
 }
 
 /// Builder of OutlivesEnvironment.
+#[derive(Debug)]
 struct OutlivesEnvironmentBuilder<'tcx> {
     param_env: ty::ParamEnv<'tcx>,
     region_relation: TransitiveRelationBuilder<Region<'tcx>>,
@@ -109,6 +110,7 @@ impl<'tcx> OutlivesEnvironment<'tcx> {
 
 impl<'a, 'tcx> OutlivesEnvironmentBuilder<'tcx> {
     #[inline]
+    #[instrument(level = "debug")]
     fn build(self) -> OutlivesEnvironment<'tcx> {
         OutlivesEnvironment {
             param_env: self.param_env,
@@ -140,6 +142,10 @@ impl<'a, 'tcx> OutlivesEnvironmentBuilder<'tcx> {
                     self.region_bound_pairs
                         .insert(ty::OutlivesPredicate(GenericKind::Projection(projection_b), r_a));
                 }
+                OutlivesBound::RegionSubOpaque(r_a, def_id, substs) => {
+                    self.region_bound_pairs
+                        .insert(ty::OutlivesPredicate(GenericKind::Opaque(def_id, substs), r_a));
+                }
                 OutlivesBound::RegionSubRegion(r_a, r_b) => {
                     if let (ReEarlyBound(_) | ReFree(_), ReVar(vid_b)) = (r_a.kind(), r_b.kind()) {
                         infcx
diff --git a/compiler/rustc_infer/src/infer/outlives/mod.rs b/compiler/rustc_infer/src/infer/outlives/mod.rs
index 2a085288fb7c..2d19d1823fdf 100644
--- a/compiler/rustc_infer/src/infer/outlives/mod.rs
+++ b/compiler/rustc_infer/src/infer/outlives/mod.rs
@@ -9,7 +9,7 @@ pub mod verify;
 use rustc_middle::traits::query::OutlivesBound;
 use rustc_middle::ty;
 
-#[instrument(level = "debug", skip(param_env))]
+#[instrument(level = "debug", skip(param_env), ret)]
 pub fn explicit_outlives_bounds<'tcx>(
     param_env: ty::ParamEnv<'tcx>,
 ) -> impl Iterator<Item = OutlivesBound<'tcx>> + 'tcx {
diff --git a/compiler/rustc_infer/src/infer/outlives/obligations.rs b/compiler/rustc_infer/src/infer/outlives/obligations.rs
index fe78890ff6ed..229b69b92e68 100644
--- a/compiler/rustc_infer/src/infer/outlives/obligations.rs
+++ b/compiler/rustc_infer/src/infer/outlives/obligations.rs
@@ -68,9 +68,11 @@ use crate::infer::{
 };
 use crate::traits::{ObligationCause, ObligationCauseCode};
 use rustc_data_structures::undo_log::UndoLogs;
+use rustc_hir::def_id::DefId;
 use rustc_hir::def_id::LocalDefId;
+use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::ty::subst::GenericArgKind;
-use rustc_middle::ty::{self, Region, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, Region, SubstsRef, Ty, TyCtxt, TypeVisitable};
 use smallvec::smallvec;
 
 impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
@@ -163,7 +165,8 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
 
             let outlives =
                 &mut TypeOutlives::new(self, self.tcx, &region_bound_pairs, None, param_env);
-            outlives.type_must_outlive(origin, sup_type, sub_region);
+            let category = origin.to_constraint_category();
+            outlives.type_must_outlive(origin, sup_type, sub_region, category);
         }
     }
 
@@ -207,6 +210,7 @@ pub trait TypeOutlivesDelegate<'tcx> {
         origin: SubregionOrigin<'tcx>,
         a: ty::Region<'tcx>,
         b: ty::Region<'tcx>,
+        constraint_category: ConstraintCategory<'tcx>,
     );
 
     fn push_verify(
@@ -255,12 +259,13 @@ where
         origin: infer::SubregionOrigin<'tcx>,
         ty: Ty<'tcx>,
         region: ty::Region<'tcx>,
+        category: ConstraintCategory<'tcx>,
     ) {
         assert!(!ty.has_escaping_bound_vars());
 
         let mut components = smallvec![];
         push_outlives_components(self.tcx, ty, &mut components);
-        self.components_must_outlive(origin, &components, region);
+        self.components_must_outlive(origin, &components, region, category);
     }
 
     fn components_must_outlive(
@@ -268,21 +273,25 @@ where
         origin: infer::SubregionOrigin<'tcx>,
         components: &[Component<'tcx>],
         region: ty::Region<'tcx>,
+        category: ConstraintCategory<'tcx>,
     ) {
         for component in components.iter() {
             let origin = origin.clone();
             match component {
                 Component::Region(region1) => {
-                    self.delegate.push_sub_region_constraint(origin, region, *region1);
+                    self.delegate.push_sub_region_constraint(origin, region, *region1, category);
                 }
                 Component::Param(param_ty) => {
                     self.param_ty_must_outlive(origin, region, *param_ty);
                 }
+                Component::Opaque(def_id, substs) => {
+                    self.opaque_must_outlive(*def_id, substs, origin, region)
+                }
                 Component::Projection(projection_ty) => {
                     self.projection_must_outlive(origin, region, *projection_ty);
                 }
                 Component::EscapingProjection(subcomponents) => {
-                    self.components_must_outlive(origin, &subcomponents, region);
+                    self.components_must_outlive(origin, &subcomponents, region, category);
                 }
                 Component::UnresolvedInferenceVariable(v) => {
                     // ignore this, we presume it will yield an error
@@ -309,17 +318,69 @@ where
         );
 
         let generic = GenericKind::Param(param_ty);
-        let verify_bound = self.verify_bound.generic_bound(generic);
+        let verify_bound = self.verify_bound.param_bound(param_ty);
         self.delegate.push_verify(origin, generic, region, verify_bound);
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
+    fn opaque_must_outlive(
+        &mut self,
+        def_id: DefId,
+        substs: SubstsRef<'tcx>,
+        origin: infer::SubregionOrigin<'tcx>,
+        region: ty::Region<'tcx>,
+    ) {
+        self.generic_must_outlive(
+            origin,
+            region,
+            GenericKind::Opaque(def_id, substs),
+            def_id,
+            substs,
+            true,
+            |ty| match *ty.kind() {
+                ty::Opaque(def_id, substs) => (def_id, substs),
+                _ => bug!("expected only projection types from env, not {:?}", ty),
+            },
+        );
+    }
+
+    #[instrument(level = "debug", skip(self))]
     fn projection_must_outlive(
         &mut self,
         origin: infer::SubregionOrigin<'tcx>,
         region: ty::Region<'tcx>,
         projection_ty: ty::ProjectionTy<'tcx>,
     ) {
+        self.generic_must_outlive(
+            origin,
+            region,
+            GenericKind::Projection(projection_ty),
+            projection_ty.item_def_id,
+            projection_ty.substs,
+            false,
+            |ty| match ty.kind() {
+                ty::Projection(projection_ty) => (projection_ty.item_def_id, projection_ty.substs),
+                _ => bug!("expected only projection types from env, not {:?}", ty),
+            },
+        );
+    }
+
+    #[instrument(level = "debug", skip(self, filter))]
+    fn generic_must_outlive(
+        &mut self,
+        origin: infer::SubregionOrigin<'tcx>,
+        region: ty::Region<'tcx>,
+        generic: GenericKind<'tcx>,
+        def_id: DefId,
+        substs: SubstsRef<'tcx>,
+        is_opaque: bool,
+        filter: impl Fn(Ty<'tcx>) -> (DefId, SubstsRef<'tcx>),
+    ) {
+        // An optimization for a common case with opaque types.
+        if substs.is_empty() {
+            return;
+        }
+
         // This case is thorny for inference. The fundamental problem is
         // that there are many cases where we have choice, and inference
         // doesn't like choice (the current region inference in
@@ -338,16 +399,15 @@ where
         // These are guaranteed to apply, no matter the inference
         // results.
         let trait_bounds: Vec<_> =
-            self.verify_bound.projection_declared_bounds_from_trait(projection_ty).collect();
+            self.verify_bound.declared_region_bounds(def_id, substs).collect();
 
         debug!(?trait_bounds);
 
         // Compute the bounds we can derive from the environment. This
         // is an "approximate" match -- in some cases, these bounds
         // may not apply.
-        let mut approx_env_bounds =
-            self.verify_bound.projection_approx_declared_bounds_from_env(projection_ty);
-        debug!("projection_must_outlive: approx_env_bounds={:?}", approx_env_bounds);
+        let mut approx_env_bounds = self.verify_bound.approx_declared_bounds_from_env(generic);
+        debug!(?approx_env_bounds);
 
         // Remove outlives bounds that we get from the environment but
         // which are also deducible from the trait. This arises (cc
@@ -361,14 +421,8 @@ where
             // If the declaration is `trait Trait<'b> { type Item: 'b; }`, then `projection_declared_bounds_from_trait`
             // will be invoked with `['b => ^1]` and so we will get `^1` returned.
             let bound = bound_outlives.skip_binder();
-            match *bound.0.kind() {
-                ty::Projection(projection_ty) => self
-                    .verify_bound
-                    .projection_declared_bounds_from_trait(projection_ty)
-                    .all(|r| r != bound.1),
-
-                _ => panic!("expected only projection types from env, not {:?}", bound.0),
-            }
+            let (def_id, substs) = filter(bound.0);
+            self.verify_bound.declared_region_bounds(def_id, substs).all(|r| r != bound.1)
         });
 
         // If declared bounds list is empty, the only applicable rule is
@@ -385,23 +439,11 @@ where
         // the problem is to add `T: 'r`, which isn't true. So, if there are no
         // inference variables, we use a verify constraint instead of adding
         // edges, which winds up enforcing the same condition.
-        let needs_infer = projection_ty.needs_infer();
-        if approx_env_bounds.is_empty() && trait_bounds.is_empty() && needs_infer {
-            debug!("projection_must_outlive: no declared bounds");
+        let needs_infer = substs.needs_infer();
+        if approx_env_bounds.is_empty() && trait_bounds.is_empty() && (needs_infer || is_opaque) {
+            debug!("no declared bounds");
 
-            for k in projection_ty.substs {
-                match k.unpack() {
-                    GenericArgKind::Lifetime(lt) => {
-                        self.delegate.push_sub_region_constraint(origin.clone(), region, lt);
-                    }
-                    GenericArgKind::Type(ty) => {
-                        self.type_must_outlive(origin.clone(), ty, region);
-                    }
-                    GenericArgKind::Const(_) => {
-                        // Const parameters don't impose constraints.
-                    }
-                }
-            }
+            self.substs_must_outlive(substs, origin, region);
 
             return;
         }
@@ -431,9 +473,10 @@ where
                 .all(|b| b == Some(trait_bounds[0]))
         {
             let unique_bound = trait_bounds[0];
-            debug!("projection_must_outlive: unique trait bound = {:?}", unique_bound);
-            debug!("projection_must_outlive: unique declared bound appears in trait ref");
-            self.delegate.push_sub_region_constraint(origin, region, unique_bound);
+            debug!(?unique_bound);
+            debug!("unique declared bound appears in trait ref");
+            let category = origin.to_constraint_category();
+            self.delegate.push_sub_region_constraint(origin, region, unique_bound, category);
             return;
         }
 
@@ -442,11 +485,42 @@ where
         // projection outlive; in some cases, this may add insufficient
         // edges into the inference graph, leading to inference failures
         // even though a satisfactory solution exists.
-        let generic = GenericKind::Projection(projection_ty);
-        let verify_bound = self.verify_bound.generic_bound(generic);
+        let verify_bound = self.verify_bound.projection_opaque_bounds(
+            generic,
+            def_id,
+            substs,
+            &mut Default::default(),
+        );
         debug!("projection_must_outlive: pushing {:?}", verify_bound);
         self.delegate.push_verify(origin, generic, region, verify_bound);
     }
+
+    fn substs_must_outlive(
+        &mut self,
+        substs: SubstsRef<'tcx>,
+        origin: infer::SubregionOrigin<'tcx>,
+        region: ty::Region<'tcx>,
+    ) {
+        let constraint = origin.to_constraint_category();
+        for k in substs {
+            match k.unpack() {
+                GenericArgKind::Lifetime(lt) => {
+                    self.delegate.push_sub_region_constraint(
+                        origin.clone(),
+                        region,
+                        lt,
+                        constraint,
+                    );
+                }
+                GenericArgKind::Type(ty) => {
+                    self.type_must_outlive(origin.clone(), ty, region, constraint);
+                }
+                GenericArgKind::Const(_) => {
+                    // Const parameters don't impose constraints.
+                }
+            }
+        }
+    }
 }
 
 impl<'cx, 'tcx> TypeOutlivesDelegate<'tcx> for &'cx InferCtxt<'cx, 'tcx> {
@@ -455,6 +529,7 @@ impl<'cx, 'tcx> TypeOutlivesDelegate<'tcx> for &'cx InferCtxt<'cx, 'tcx> {
         origin: SubregionOrigin<'tcx>,
         a: ty::Region<'tcx>,
         b: ty::Region<'tcx>,
+        _constraint_category: ConstraintCategory<'tcx>,
     ) {
         self.sub_regions(origin, a, b)
     }
diff --git a/compiler/rustc_infer/src/infer/outlives/test_type_match.rs b/compiler/rustc_infer/src/infer/outlives/test_type_match.rs
index be03c8b5bae9..a5c21f0fb9b5 100644
--- a/compiler/rustc_infer/src/infer/outlives/test_type_match.rs
+++ b/compiler/rustc_infer/src/infer/outlives/test_type_match.rs
@@ -34,7 +34,7 @@ use crate::infer::region_constraints::VerifyIfEq;
 /// like are used. This is a particular challenge since this function is invoked
 /// very late in inference and hence cannot make use of the normal inference
 /// machinery.
-#[tracing::instrument(level = "debug", skip(tcx, param_env))]
+#[instrument(level = "debug", skip(tcx, param_env))]
 pub fn extract_verify_if_eq<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -71,7 +71,7 @@ pub fn extract_verify_if_eq<'tcx>(
 }
 
 /// True if a (potentially higher-ranked) outlives
-#[tracing::instrument(level = "debug", skip(tcx, param_env))]
+#[instrument(level = "debug", skip(tcx, param_env))]
 pub(super) fn can_match_erased_ty<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -110,7 +110,7 @@ impl<'tcx> Match<'tcx> {
 
     /// Binds the pattern variable `br` to `value`; returns an `Err` if the pattern
     /// is already bound to a different value.
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn bind(
         &mut self,
         br: ty::BoundRegion,
diff --git a/compiler/rustc_infer/src/infer/outlives/verify.rs b/compiler/rustc_infer/src/infer/outlives/verify.rs
index c7d7ef40d9d4..f470b2eb8c19 100644
--- a/compiler/rustc_infer/src/infer/outlives/verify.rs
+++ b/compiler/rustc_infer/src/infer/outlives/verify.rs
@@ -2,11 +2,10 @@ use crate::infer::outlives::components::{compute_components_recursive, Component
 use crate::infer::outlives::env::RegionBoundPairs;
 use crate::infer::region_constraints::VerifyIfEq;
 use crate::infer::{GenericKind, VerifyBound};
-use rustc_data_structures::captures::Captures;
 use rustc_data_structures::sso::SsoHashSet;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::subst::{GenericArg, Subst};
-use rustc_middle::ty::{self, EarlyBinder, OutlivesPredicate, Ty, TyCtxt};
+use rustc_middle::ty::GenericArg;
+use rustc_middle::ty::{self, EarlyBinder, OutlivesPredicate, SubstsRef, Ty, TyCtxt};
 
 use smallvec::smallvec;
 
@@ -38,25 +37,13 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         Self { tcx, region_bound_pairs, implicit_region_bound, param_env }
     }
 
-    /// Returns a "verify bound" that encodes what we know about
-    /// `generic` and the regions it outlives.
-    pub fn generic_bound(&self, generic: GenericKind<'tcx>) -> VerifyBound<'tcx> {
-        let mut visited = SsoHashSet::new();
-        match generic {
-            GenericKind::Param(param_ty) => self.param_bound(param_ty),
-            GenericKind::Projection(projection_ty) => {
-                self.projection_bound(projection_ty, &mut visited)
-            }
-        }
-    }
-
-    fn param_bound(&self, param_ty: ty::ParamTy) -> VerifyBound<'tcx> {
-        debug!("param_bound(param_ty={:?})", param_ty);
-
+    #[instrument(level = "debug", skip(self))]
+    pub fn param_bound(&self, param_ty: ty::ParamTy) -> VerifyBound<'tcx> {
         // Start with anything like `T: 'a` we can scrape from the
         // environment. If the environment contains something like
         // `for<'a> T: 'a`, then we know that `T` outlives everything.
         let declared_bounds_from_env = self.declared_generic_bounds_from_env(param_ty);
+        debug!(?declared_bounds_from_env);
         let mut param_bounds = vec![];
         for declared_bound in declared_bounds_from_env {
             let bound_region = declared_bound.map_bound(|outlives| outlives.1);
@@ -65,6 +52,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
                 param_bounds.push(VerifyBound::OutlivedBy(region));
             } else {
                 // This is `for<'a> T: 'a`. This means that `T` outlives everything! All done here.
+                debug!("found that {param_ty:?} outlives any lifetime, returning empty vector");
                 return VerifyBound::AllBounds(vec![]);
             }
         }
@@ -72,6 +60,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         // Add in the default bound of fn body that applies to all in
         // scope type parameters:
         if let Some(r) = self.implicit_region_bound {
+            debug!("adding implicit region bound of {r:?}");
             param_bounds.push(VerifyBound::OutlivedBy(r));
         }
 
@@ -103,41 +92,31 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     /// the clause from the environment only applies if `'0 = 'a`,
     /// which we don't know yet. But we would still include `'b` in
     /// this list.
-    pub fn projection_approx_declared_bounds_from_env(
+    pub fn approx_declared_bounds_from_env(
         &self,
-        projection_ty: ty::ProjectionTy<'tcx>,
+        generic: GenericKind<'tcx>,
     ) -> Vec<ty::Binder<'tcx, ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>>> {
-        let projection_ty = GenericKind::Projection(projection_ty).to_ty(self.tcx);
+        let projection_ty = generic.to_ty(self.tcx);
         let erased_projection_ty = self.tcx.erase_regions(projection_ty);
         self.declared_generic_bounds_from_env_for_erased_ty(erased_projection_ty)
     }
 
-    /// Searches the where-clauses in scope for regions that
-    /// `projection_ty` is known to outlive. Currently requires an
-    /// exact match.
-    pub fn projection_declared_bounds_from_trait(
+    #[instrument(level = "debug", skip(self, visited))]
+    pub fn projection_opaque_bounds(
         &self,
-        projection_ty: ty::ProjectionTy<'tcx>,
-    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'tcx> {
-        self.declared_projection_bounds_from_trait(projection_ty)
-    }
-
-    pub fn projection_bound(
-        &self,
-        projection_ty: ty::ProjectionTy<'tcx>,
+        generic: GenericKind<'tcx>,
+        def_id: DefId,
+        substs: SubstsRef<'tcx>,
         visited: &mut SsoHashSet<GenericArg<'tcx>>,
     ) -> VerifyBound<'tcx> {
-        debug!("projection_bound(projection_ty={:?})", projection_ty);
-
-        let projection_ty_as_ty =
-            self.tcx.mk_projection(projection_ty.item_def_id, projection_ty.substs);
+        let generic_ty = generic.to_ty(self.tcx);
 
         // Search the env for where clauses like `P: 'a`.
-        let env_bounds = self
-            .projection_approx_declared_bounds_from_env(projection_ty)
+        let projection_opaque_bounds = self
+            .approx_declared_bounds_from_env(generic)
             .into_iter()
             .map(|binder| {
-                if let Some(ty::OutlivesPredicate(ty, r)) = binder.no_bound_vars() && ty == projection_ty_as_ty {
+                if let Some(ty::OutlivesPredicate(ty, r)) = binder.no_bound_vars() && ty == generic_ty {
                     // Micro-optimize if this is an exact match (this
                     // occurs often when there are no region variables
                     // involved).
@@ -147,21 +126,19 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
                     VerifyBound::IfEq(verify_if_eq_b)
                 }
             });
-
         // Extend with bounds that we can find from the trait.
-        let trait_bounds = self
-            .projection_declared_bounds_from_trait(projection_ty)
-            .map(|r| VerifyBound::OutlivedBy(r));
+        let trait_bounds =
+            self.declared_region_bounds(def_id, substs).map(|r| VerifyBound::OutlivedBy(r));
 
         // see the extensive comment in projection_must_outlive
         let recursive_bound = {
             let mut components = smallvec![];
-            let ty = self.tcx.mk_projection(projection_ty.item_def_id, projection_ty.substs);
-            compute_components_recursive(self.tcx, ty.into(), &mut components, visited);
+            compute_components_recursive(self.tcx, generic_ty.into(), &mut components, visited);
             self.bound_from_components(&components, visited)
         };
 
-        VerifyBound::AnyBound(env_bounds.chain(trait_bounds).collect()).or(recursive_bound)
+        VerifyBound::AnyBound(projection_opaque_bounds.chain(trait_bounds).collect())
+            .or(recursive_bound)
     }
 
     fn bound_from_components(
@@ -193,7 +170,18 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         match *component {
             Component::Region(lt) => VerifyBound::OutlivedBy(lt),
             Component::Param(param_ty) => self.param_bound(param_ty),
-            Component::Projection(projection_ty) => self.projection_bound(projection_ty, visited),
+            Component::Opaque(did, substs) => self.projection_opaque_bounds(
+                GenericKind::Opaque(did, substs),
+                did,
+                substs,
+                visited,
+            ),
+            Component::Projection(projection_ty) => self.projection_opaque_bounds(
+                GenericKind::Projection(projection_ty),
+                projection_ty.item_def_id,
+                projection_ty.substs,
+                visited,
+            ),
             Component::EscapingProjection(ref components) => {
                 self.bound_from_components(components, visited)
             }
@@ -291,30 +279,6 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     /// }
     /// ```
     ///
-    /// then this function would return `'x`. This is subject to the
-    /// limitations around higher-ranked bounds described in
-    /// `region_bounds_declared_on_associated_item`.
-    fn declared_projection_bounds_from_trait(
-        &self,
-        projection_ty: ty::ProjectionTy<'tcx>,
-    ) -> impl Iterator<Item = ty::Region<'tcx>> + 'cx + Captures<'tcx> {
-        debug!("projection_bounds(projection_ty={:?})", projection_ty);
-        let tcx = self.tcx;
-        self.region_bounds_declared_on_associated_item(projection_ty.item_def_id)
-            .map(move |r| EarlyBinder(r).subst(tcx, projection_ty.substs))
-    }
-
-    /// Given the `DefId` of an associated item, returns any region
-    /// bounds attached to that associated item from the trait definition.
-    ///
-    /// For example:
-    ///
-    /// ```rust
-    /// trait Foo<'a> {
-    ///     type Bar: 'a;
-    /// }
-    /// ```
-    ///
     /// If we were given the `DefId` of `Foo::Bar`, we would return
     /// `'a`. You could then apply the substitutions from the
     /// projection to convert this into your namespace. This also
@@ -334,17 +298,20 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     ///
     /// This is for simplicity, and because we are not really smart
     /// enough to cope with such bounds anywhere.
-    fn region_bounds_declared_on_associated_item(
+    pub fn declared_region_bounds(
         &self,
-        assoc_item_def_id: DefId,
+        def_id: DefId,
+        substs: SubstsRef<'tcx>,
     ) -> impl Iterator<Item = ty::Region<'tcx>> {
         let tcx = self.tcx;
-        let bounds = tcx.item_bounds(assoc_item_def_id);
+        let bounds = tcx.item_bounds(def_id);
+        trace!("{:#?}", bounds);
         bounds
             .into_iter()
             .filter_map(|p| p.to_opt_type_outlives())
             .filter_map(|p| p.no_bound_vars())
             .map(|b| b.1)
+            .map(move |r| EarlyBinder(r).subst(tcx, substs))
     }
 
     /// Searches through a predicate list for a predicate `T: 'a`.
diff --git a/compiler/rustc_infer/src/infer/region_constraints/mod.rs b/compiler/rustc_infer/src/infer/region_constraints/mod.rs
index 780e6ead10ef..67b3da687200 100644
--- a/compiler/rustc_infer/src/infer/region_constraints/mod.rs
+++ b/compiler/rustc_infer/src/infer/region_constraints/mod.rs
@@ -12,8 +12,10 @@ use rustc_data_structures::intern::Interned;
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::undo_log::UndoLogs;
 use rustc_data_structures::unify as ut;
+use rustc_hir::def_id::DefId;
 use rustc_index::vec::IndexVec;
 use rustc_middle::infer::unify_key::{RegionVidKey, UnifiedRegion};
+use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::ReStatic;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::ty::{ReLateBound, ReVar};
@@ -168,6 +170,7 @@ pub struct Verify<'tcx> {
 pub enum GenericKind<'tcx> {
     Param(ty::ParamTy),
     Projection(ty::ProjectionTy<'tcx>),
+    Opaque(DefId, SubstsRef<'tcx>),
 }
 
 /// Describes the things that some `GenericKind` value `G` is known to
@@ -426,21 +429,21 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         data
     }
 
-    pub fn data(&self) -> &RegionConstraintData<'tcx> {
+    pub(super) fn data(&self) -> &RegionConstraintData<'tcx> {
         &self.data
     }
 
-    pub fn start_snapshot(&mut self) -> RegionSnapshot {
+    pub(super) fn start_snapshot(&mut self) -> RegionSnapshot {
         debug!("RegionConstraintCollector: start_snapshot");
         RegionSnapshot { any_unifications: self.any_unifications }
     }
 
-    pub fn rollback_to(&mut self, snapshot: RegionSnapshot) {
+    pub(super) fn rollback_to(&mut self, snapshot: RegionSnapshot) {
         debug!("RegionConstraintCollector: rollback_to({:?})", snapshot);
         self.any_unifications = snapshot.any_unifications;
     }
 
-    pub fn new_region_var(
+    pub(super) fn new_region_var(
         &mut self,
         universe: ty::UniverseIndex,
         origin: RegionVariableOrigin,
@@ -455,12 +458,12 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
     }
 
     /// Returns the universe for the given variable.
-    pub fn var_universe(&self, vid: RegionVid) -> ty::UniverseIndex {
+    pub(super) fn var_universe(&self, vid: RegionVid) -> ty::UniverseIndex {
         self.var_infos[vid].universe
     }
 
     /// Returns the origin for the given variable.
-    pub fn var_origin(&self, vid: RegionVid) -> RegionVariableOrigin {
+    pub(super) fn var_origin(&self, vid: RegionVid) -> RegionVariableOrigin {
         self.var_infos[vid].origin
     }
 
@@ -492,7 +495,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         self.undo_log.push(AddVerify(index));
     }
 
-    pub fn add_given(&mut self, sub: Region<'tcx>, sup: ty::RegionVid) {
+    pub(super) fn add_given(&mut self, sub: Region<'tcx>, sup: ty::RegionVid) {
         // cannot add givens once regions are resolved
         if self.data.givens.insert((sub, sup)) {
             debug!("add_given({:?} <= {:?})", sub, sup);
@@ -501,7 +504,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         }
     }
 
-    pub fn make_eqregion(
+    pub(super) fn make_eqregion(
         &mut self,
         origin: SubregionOrigin<'tcx>,
         sub: Region<'tcx>,
@@ -530,7 +533,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         }
     }
 
-    pub fn member_constraint(
+    pub(super) fn member_constraint(
         &mut self,
         key: ty::OpaqueTypeKey<'tcx>,
         definition_span: Span,
@@ -554,7 +557,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
     }
 
     #[instrument(skip(self, origin), level = "debug")]
-    pub fn make_subregion(
+    pub(super) fn make_subregion(
         &mut self,
         origin: SubregionOrigin<'tcx>,
         sub: Region<'tcx>,
@@ -585,7 +588,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         }
     }
 
-    pub fn verify_generic_bound(
+    pub(super) fn verify_generic_bound(
         &mut self,
         origin: SubregionOrigin<'tcx>,
         kind: GenericKind<'tcx>,
@@ -595,7 +598,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         self.add_verify(Verify { kind, origin, region: sub, bound });
     }
 
-    pub fn lub_regions(
+    pub(super) fn lub_regions(
         &mut self,
         tcx: TyCtxt<'tcx>,
         origin: SubregionOrigin<'tcx>,
@@ -613,7 +616,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         }
     }
 
-    pub fn glb_regions(
+    pub(super) fn glb_regions(
         &mut self,
         tcx: TyCtxt<'tcx>,
         origin: SubregionOrigin<'tcx>,
@@ -634,7 +637,7 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
     }
 
     /// Resolves the passed RegionVid to the root RegionVid in the unification table
-    pub fn opportunistic_resolve_var(&mut self, rid: ty::RegionVid) -> ty::RegionVid {
+    pub(super) fn opportunistic_resolve_var(&mut self, rid: ty::RegionVid) -> ty::RegionVid {
         self.unification_table().find(rid).vid
     }
 
@@ -699,7 +702,6 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
             ty::ReStatic | ty::ReErased | ty::ReFree(..) | ty::ReEarlyBound(..) => {
                 ty::UniverseIndex::ROOT
             }
-            ty::ReEmpty(ui) => ui,
             ty::RePlaceholder(placeholder) => placeholder.universe,
             ty::ReVar(vid) => self.var_universe(vid),
             ty::ReLateBound(..) => bug!("universe(): encountered bound region {:?}", region),
@@ -748,6 +750,9 @@ impl<'tcx> fmt::Debug for GenericKind<'tcx> {
         match *self {
             GenericKind::Param(ref p) => write!(f, "{:?}", p),
             GenericKind::Projection(ref p) => write!(f, "{:?}", p),
+            GenericKind::Opaque(def_id, substs) => ty::tls::with(|tcx| {
+                write!(f, "{}", tcx.def_path_str_with_substs(def_id, tcx.lift(substs).unwrap()))
+            }),
         }
     }
 }
@@ -757,6 +762,9 @@ impl<'tcx> fmt::Display for GenericKind<'tcx> {
         match *self {
             GenericKind::Param(ref p) => write!(f, "{}", p),
             GenericKind::Projection(ref p) => write!(f, "{}", p),
+            GenericKind::Opaque(def_id, substs) => ty::tls::with(|tcx| {
+                write!(f, "{}", tcx.def_path_str_with_substs(def_id, tcx.lift(substs).unwrap()))
+            }),
         }
     }
 }
@@ -766,6 +774,7 @@ impl<'tcx> GenericKind<'tcx> {
         match *self {
             GenericKind::Param(ref p) => p.to_ty(tcx),
             GenericKind::Projection(ref p) => tcx.mk_projection(p.item_def_id, p.substs),
+            GenericKind::Opaque(def_id, substs) => tcx.mk_opaque(def_id, substs),
         }
     }
 }
diff --git a/compiler/rustc_infer/src/infer/sub.rs b/compiler/rustc_infer/src/infer/sub.rs
index b7eab5d43285..375dd670fabf 100644
--- a/compiler/rustc_infer/src/infer/sub.rs
+++ b/compiler/rustc_infer/src/infer/sub.rs
@@ -164,6 +164,24 @@ impl<'tcx> TypeRelation<'tcx> for Sub<'_, '_, 'tcx> {
                 );
                 Ok(ga)
             }
+            // Optimization of GeneratorWitness relation since we know that all
+            // free regions are replaced with bound regions during construction.
+            // This greatly speeds up subtyping of GeneratorWitness.
+            (&ty::GeneratorWitness(a_types), &ty::GeneratorWitness(b_types)) => {
+                let a_types = infcx.tcx.anonymize_bound_vars(a_types);
+                let b_types = infcx.tcx.anonymize_bound_vars(b_types);
+                if a_types.bound_vars() == b_types.bound_vars() {
+                    let (a_types, b_types) = infcx.replace_bound_vars_with_placeholders(
+                        a_types.map_bound(|a_types| (a_types, b_types.skip_binder())),
+                    );
+                    for (a, b) in std::iter::zip(a_types, b_types) {
+                        self.relate(a, b)?;
+                    }
+                    Ok(a)
+                } else {
+                    Err(ty::error::TypeError::Sorts(ty::relate::expected_found(self, a, b)))
+                }
+            }
 
             _ => {
                 self.fields.infcx.super_combine_tys(self, a, b)?;
diff --git a/compiler/rustc_infer/src/infer/type_variable.rs b/compiler/rustc_infer/src/infer/type_variable.rs
index a0e2965b6051..7ff086452536 100644
--- a/compiler/rustc_infer/src/infer/type_variable.rs
+++ b/compiler/rustc_infer/src/infer/type_variable.rs
@@ -122,6 +122,7 @@ pub enum TypeVariableOriginKind {
     MiscVariable,
     NormalizeProjectionType,
     TypeInference,
+    OpaqueTypeInference(DefId),
     TypeParameterDefinition(Symbol, Option<DefId>),
 
     /// One of the upvars or closure kind parameters in a `ClosureSubsts`
diff --git a/compiler/rustc_infer/src/infer/undo_log.rs b/compiler/rustc_infer/src/infer/undo_log.rs
index 74a26ebc39f8..611961ab1cc9 100644
--- a/compiler/rustc_infer/src/infer/undo_log.rs
+++ b/compiler/rustc_infer/src/infer/undo_log.rs
@@ -100,7 +100,7 @@ impl Default for InferCtxtUndoLogs<'_> {
 }
 
 /// The UndoLogs trait defines how we undo a particular kind of action (of type T). We can undo any
-/// action that is convertable into an UndoLog (per the From impls above).
+/// action that is convertible into an UndoLog (per the From impls above).
 impl<'tcx, T> UndoLogs<T> for InferCtxtUndoLogs<'tcx>
 where
     UndoLog<'tcx>: From<T>,
diff --git a/compiler/rustc_infer/src/lib.rs b/compiler/rustc_infer/src/lib.rs
index 931ebca7d014..b91c098ab03d 100644
--- a/compiler/rustc_infer/src/lib.rs
+++ b/compiler/rustc_infer/src/lib.rs
@@ -17,9 +17,8 @@
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
 #![feature(extend_one)]
-#![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![feature(if_let_guard)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(try_blocks)]
diff --git a/compiler/rustc_infer/src/traits/mod.rs b/compiler/rustc_infer/src/traits/mod.rs
index 4df4de21a0f0..c8600ded987e 100644
--- a/compiler/rustc_infer/src/traits/mod.rs
+++ b/compiler/rustc_infer/src/traits/mod.rs
@@ -67,6 +67,14 @@ impl<'tcx> PredicateObligation<'tcx> {
             recursion_depth: self.recursion_depth,
         })
     }
+
+    pub fn without_const(mut self, tcx: TyCtxt<'tcx>) -> PredicateObligation<'tcx> {
+        self.param_env = self.param_env.without_const();
+        if let ty::PredicateKind::Trait(trait_pred) = self.predicate.kind().skip_binder() && trait_pred.is_const_if_const() {
+            self.predicate = tcx.mk_predicate(self.predicate.kind().map_bound(|_| ty::PredicateKind::Trait(trait_pred.without_const())));
+        }
+        self
+    }
 }
 
 impl<'tcx> TraitObligation<'tcx> {
@@ -105,6 +113,8 @@ pub struct FulfillmentError<'tcx> {
 
 #[derive(Clone)]
 pub enum FulfillmentErrorCode<'tcx> {
+    /// Inherently impossible to fulfill; this trait is implemented if and only if it is already implemented.
+    CodeCycle(Vec<Obligation<'tcx, ty::Predicate<'tcx>>>),
     CodeSelectionError(SelectionError<'tcx>),
     CodeProjectionError(MismatchedProjectionTypes<'tcx>),
     CodeSubtypeError(ExpectedFound<Ty<'tcx>>, TypeError<'tcx>), // always comes from a SubtypePredicate
diff --git a/compiler/rustc_infer/src/traits/structural_impls.rs b/compiler/rustc_infer/src/traits/structural_impls.rs
index 573d2d1e3301..1c6ab6a082b9 100644
--- a/compiler/rustc_infer/src/traits/structural_impls.rs
+++ b/compiler/rustc_infer/src/traits/structural_impls.rs
@@ -47,6 +47,7 @@ impl<'tcx> fmt::Debug for traits::FulfillmentErrorCode<'tcx> {
                 write!(f, "CodeConstEquateError({:?}, {:?})", a, b)
             }
             super::CodeAmbiguity => write!(f, "Ambiguity"),
+            super::CodeCycle(ref cycle) => write!(f, "Cycle({:?})", cycle),
         }
     }
 }
diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs
index f5a1edf6d813..e12c069dcc1d 100644
--- a/compiler/rustc_infer/src/traits/util.rs
+++ b/compiler/rustc_infer/src/traits/util.rs
@@ -246,6 +246,13 @@ impl<'tcx> Elaborator<'tcx> {
 
                             Component::UnresolvedInferenceVariable(_) => None,
 
+                            Component::Opaque(def_id, substs) => {
+                                let ty = tcx.mk_opaque(def_id, substs);
+                                Some(ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(
+                                    ty, r_min,
+                                )))
+                            }
+
                             Component::Projection(projection) => {
                                 // We might end up here if we have `Foo<<Bar as Baz>::Assoc>: 'a`.
                                 // With this, we can deduce that `<Bar as Baz>::Assoc: 'a`.
@@ -262,8 +269,9 @@ impl<'tcx> Elaborator<'tcx> {
                                 None
                             }
                         })
-                        .map(ty::Binder::dummy)
-                        .map(|predicate_kind| predicate_kind.to_predicate(tcx))
+                        .map(|predicate_kind| {
+                            bound_predicate.rebind(predicate_kind).to_predicate(tcx)
+                        })
                         .filter(|&predicate| visited.insert(predicate))
                         .map(|predicate| {
                             predicate_obligation(
diff --git a/compiler/rustc_interface/src/errors.rs b/compiler/rustc_interface/src/errors.rs
index 6a497aed4aba..097640f26c15 100644
--- a/compiler/rustc_interface/src/errors.rs
+++ b/compiler/rustc_interface/src/errors.rs
@@ -1,10 +1,10 @@
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 
 use std::io;
 use std::path::Path;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::ferris_identifier)]
 pub struct FerrisIdentifier {
     #[primary_span]
@@ -13,7 +13,7 @@ pub struct FerrisIdentifier {
     pub first_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::emoji_identifier)]
 pub struct EmojiIdentifier {
     #[primary_span]
@@ -21,67 +21,67 @@ pub struct EmojiIdentifier {
     pub ident: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::mixed_bin_crate)]
 pub struct MixedBinCrate;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::mixed_proc_macro_crate)]
 pub struct MixedProcMacroCrate;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::proc_macro_doc_without_arg)]
 pub struct ProcMacroDocWithoutArg;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::error_writing_dependencies)]
 pub struct ErrorWritingDependencies<'a> {
     pub path: &'a Path,
     pub error: io::Error,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::input_file_would_be_overwritten)]
 pub struct InputFileWouldBeOverWritten<'a> {
     pub path: &'a Path,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::generated_file_conflicts_with_directory)]
 pub struct GeneratedFileConflictsWithDirectory<'a> {
     pub input_path: &'a Path,
     pub dir_path: &'a Path,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::temps_dir_error)]
 pub struct TempsDirError;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::out_dir_error)]
 pub struct OutDirError;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::cant_emit_mir)]
 pub struct CantEmitMIR {
     pub error: io::Error,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::rustc_error_fatal)]
 pub struct RustcErrorFatal {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::rustc_error_unexpected_annotation)]
 pub struct RustcErrorUnexpectedAnnotation {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(interface::failed_writing_file)]
 pub struct FailedWritingFile<'a> {
     pub path: &'a Path,
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index dc4799e4afce..949bd02ad683 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -176,7 +176,7 @@ pub fn parse_check_cfg(specs: Vec<String>) -> CheckCfg {
                                         let ident = arg.ident().expect("multi-segment cfg key");
                                         names_valid.insert(ident.name.to_string());
                                     } else {
-                                        error!("`names()` arguments must be simple identifers");
+                                        error!("`names()` arguments must be simple identifiers");
                                     }
                                 }
                                 continue 'specs;
@@ -204,7 +204,7 @@ pub fn parse_check_cfg(specs: Vec<String>) -> CheckCfg {
                                         continue 'specs;
                                     } else {
                                         error!(
-                                            "`values()` first argument must be a simple identifer"
+                                            "`values()` first argument must be a simple identifier"
                                         );
                                     }
                                 } else if args.is_empty() {
@@ -332,7 +332,7 @@ pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R
 // JUSTIFICATION: before session exists, only config
 #[allow(rustc::bad_opt_access)]
 pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Send) -> R {
-    tracing::trace!("run_compiler");
+    trace!("run_compiler");
     util::run_in_thread_pool_with_globals(
         config.opts.edition,
         config.opts.unstable_opts.threads,
diff --git a/compiler/rustc_interface/src/lib.rs b/compiler/rustc_interface/src/lib.rs
index 258e38c3bdb9..a41a749ee68e 100644
--- a/compiler/rustc_interface/src/lib.rs
+++ b/compiler/rustc_interface/src/lib.rs
@@ -1,5 +1,4 @@
 #![feature(box_patterns)]
-#![feature(let_else)]
 #![feature(internal_output_capture)]
 #![feature(thread_spawn_unchecked)]
 #![feature(once_cell)]
@@ -8,6 +7,9 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
+#[macro_use]
+extern crate tracing;
+
 mod callbacks;
 mod errors;
 pub mod interface;
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 66c6a229b89e..c41b154c3e06 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -38,7 +38,6 @@ use rustc_span::symbol::{sym, Symbol};
 use rustc_span::FileName;
 use rustc_trait_selection::traits;
 use rustc_typeck as typeck;
-use tracing::{info, warn};
 
 use std::any::Any;
 use std::cell::RefCell;
@@ -69,7 +68,7 @@ pub fn parse<'a>(sess: &'a Session, input: &Input) -> PResult<'a, ast::Crate> {
     }
 
     if sess.opts.unstable_opts.hir_stats {
-        hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
+        hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS", "ast-stats-1");
     }
 
     Ok(krate)
@@ -165,7 +164,7 @@ pub fn create_resolver(
     krate: &ast::Crate,
     crate_name: &str,
 ) -> BoxedResolver {
-    tracing::trace!("create_resolver");
+    trace!("create_resolver");
     BoxedResolver::new(sess, move |sess, resolver_arenas| {
         Resolver::new(sess, krate, crate_name, metadata_loader, resolver_arenas)
     })
@@ -279,7 +278,7 @@ pub fn configure_and_expand(
     crate_name: &str,
     resolver: &mut Resolver<'_>,
 ) -> Result<ast::Crate> {
-    tracing::trace!("configure_and_expand");
+    trace!("configure_and_expand");
     pre_expansion_lint(sess, lint_store, resolver.registered_tools(), &krate, crate_name);
     rustc_builtin_macros::register_builtin_macros(resolver);
 
@@ -416,7 +415,7 @@ pub fn configure_and_expand(
     }
 
     if sess.opts.unstable_opts.hir_stats {
-        hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
+        hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS", "ast-stats-2");
     }
 
     resolver.resolve_crate(&krate);
@@ -574,13 +573,24 @@ fn write_out_deps(
         // Account for explicitly marked-to-track files
         // (e.g. accessed in proc macros).
         let file_depinfo = sess.parse_sess.file_depinfo.borrow();
-        let extra_tracked_files = file_depinfo.iter().map(|path_sym| {
-            let path = PathBuf::from(path_sym.as_str());
+
+        let normalize_path = |path: PathBuf| {
             let file = FileName::from(path);
             escape_dep_filename(&file.prefer_local().to_string())
-        });
+        };
+
+        let extra_tracked_files =
+            file_depinfo.iter().map(|path_sym| normalize_path(PathBuf::from(path_sym.as_str())));
         files.extend(extra_tracked_files);
 
+        // We also need to track used PGO profile files
+        if let Some(ref profile_instr) = sess.opts.cg.profile_use {
+            files.push(normalize_path(profile_instr.as_path().to_path_buf()));
+        }
+        if let Some(ref profile_sample) = sess.opts.unstable_opts.profile_sample_use {
+            files.push(normalize_path(profile_sample.as_path().to_path_buf()));
+        }
+
         if sess.binary_dep_depinfo() {
             if let Some(ref backend) = sess.opts.unstable_opts.codegen_backend {
                 if backend.contains('.') {
diff --git a/compiler/rustc_interface/src/proc_macro_decls.rs b/compiler/rustc_interface/src/proc_macro_decls.rs
index 5371c513d298..2b1b931b7326 100644
--- a/compiler/rustc_interface/src/proc_macro_decls.rs
+++ b/compiler/rustc_interface/src/proc_macro_decls.rs
@@ -1,4 +1,3 @@
-use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
@@ -10,7 +9,7 @@ fn proc_macro_decls_static(tcx: TyCtxt<'_>, (): ()) -> Option<LocalDefId> {
     for id in tcx.hir().items() {
         let attrs = finder.tcx.hir().attrs(id.hir_id());
         if finder.tcx.sess.contains_name(attrs, sym::rustc_proc_macro_decls) {
-            finder.decls = Some(id.def_id);
+            finder.decls = Some(id.def_id.def_id);
         }
     }
 
@@ -19,7 +18,7 @@ fn proc_macro_decls_static(tcx: TyCtxt<'_>, (): ()) -> Option<LocalDefId> {
 
 struct Finder<'tcx> {
     tcx: TyCtxt<'tcx>,
-    decls: Option<hir::def_id::LocalDefId>,
+    decls: Option<LocalDefId>,
 }
 
 pub(crate) fn provide(providers: &mut Providers) {
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 65fa8d7495a4..6c725a01b531 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -166,7 +166,7 @@ impl<'tcx> Queries<'tcx> {
     pub fn expansion(
         &self,
     ) -> Result<&Query<(Lrc<ast::Crate>, Rc<RefCell<BoxedResolver>>, Lrc<LintStore>)>> {
-        tracing::trace!("expansion");
+        trace!("expansion");
         self.expansion.compute(|| {
             let crate_name = self.crate_name()?.peek().clone();
             let (krate, lint_store) = self.register_plugins()?.take();
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 9207a0488623..2cd959689e6c 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -21,10 +21,8 @@ use rustc_session::{build_session, getopts, DiagnosticOutput, Session};
 use rustc_span::edition::{Edition, DEFAULT_EDITION};
 use rustc_span::symbol::sym;
 use rustc_span::SourceFileHashAlgorithm;
-use rustc_target::spec::{CodeModel, LinkerFlavor, MergeFunctions, PanicStrategy};
-use rustc_target::spec::{
-    RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel,
-};
+use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, RelocModel};
+use rustc_target::spec::{RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel};
 
 use std::collections::{BTreeMap, BTreeSet};
 use std::iter::FromIterator;
@@ -552,7 +550,7 @@ fn test_codegen_options_tracking_hash() {
     untracked!(link_args, vec![String::from("abc"), String::from("def")]);
     untracked!(link_self_contained, Some(true));
     untracked!(linker, Some(PathBuf::from("linker")));
-    untracked!(linker_flavor, Some(LinkerFlavor::Gcc));
+    untracked!(linker_flavor, Some(LinkerFlavorCli::Gcc));
     untracked!(no_stack_check, true);
     untracked!(remark, Passes::Some(vec![String::from("pass1"), String::from("pass2")]));
     untracked!(rpath, true);
@@ -760,13 +758,13 @@ fn test_unstable_options_tracking_hash() {
     tracked!(mir_opt_level, Some(4));
     tracked!(move_size_limit, Some(4096));
     tracked!(mutable_noalias, Some(true));
-    tracked!(new_llvm_pass_manager, Some(true));
     tracked!(no_generate_arange_section, true);
     tracked!(no_link, true);
     tracked!(no_unique_section_names, true);
     tracked!(no_profiler_runtime, true);
     tracked!(oom, OomStrategy::Panic);
     tracked!(osx_rpath_install_name, true);
+    tracked!(packed_bundled_libs, true);
     tracked!(panic_abort_tests, true);
     tracked!(panic_in_drop, PanicStrategy::Abort);
     tracked!(pick_stable_methods_before_any_unstable, false);
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index e74978485a21..f7e70d355cf8 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -1,3 +1,4 @@
+use info;
 use libloading::Library;
 use rustc_ast as ast;
 use rustc_codegen_ssa::traits::CodegenBackend;
@@ -31,7 +32,6 @@ use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::OnceLock;
 use std::thread;
-use tracing::info;
 
 /// Function pointer type that constructs a new CodegenBackend.
 pub type MakeBackendFn = fn() -> Box<dyn CodegenBackend>;
diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index 178366f7d804..a79c982649af 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -141,7 +141,7 @@ pub enum TokenKind {
     Unknown,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum DocStyle {
     Outer,
     Inner,
diff --git a/compiler/rustc_lint/Cargo.toml b/compiler/rustc_lint/Cargo.toml
index 7c0f2c440d51..abe61406c219 100644
--- a/compiler/rustc_lint/Cargo.toml
+++ b/compiler/rustc_lint/Cargo.toml
@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 tracing = "0.1"
-unicode-security = "0.0.5"
+unicode-security = "0.1.0"
 rustc_middle = { path = "../rustc_middle" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
 rustc_attr = { path = "../rustc_attr" }
diff --git a/compiler/rustc_lint/src/array_into_iter.rs b/compiler/rustc_lint/src/array_into_iter.rs
index 121fefdc6207..b97f8acb37f8 100644
--- a/compiler/rustc_lint/src/array_into_iter.rs
+++ b/compiler/rustc_lint/src/array_into_iter.rs
@@ -61,7 +61,7 @@ impl<'tcx> LateLintPass<'tcx> for ArrayIntoIter {
         }
 
         // We only care about method call expressions.
-        if let hir::ExprKind::MethodCall(call, args, _) = &expr.kind {
+        if let hir::ExprKind::MethodCall(call, receiver_arg, ..) = &expr.kind {
             if call.ident.name != sym::into_iter {
                 return;
             }
@@ -75,7 +75,6 @@ impl<'tcx> LateLintPass<'tcx> for ArrayIntoIter {
             };
 
             // As this is a method call expression, we have at least one argument.
-            let receiver_arg = &args[0];
             let receiver_ty = cx.typeck_results().expr_ty(receiver_arg);
             let adjustments = cx.typeck_results().expr_adjustments(receiver_arg);
 
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 868555a72b0d..5fba1d3d3c7a 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -59,7 +59,6 @@ use rustc_trait_selection::traits::{self, misc::can_type_implement_copy};
 use crate::nonstandard_style::{method_context, MethodLateContext};
 
 use std::fmt::Write;
-use tracing::{debug, trace};
 
 // hardwired lints from librustc_middle
 pub use rustc_session::lint::builtin::*;
@@ -260,17 +259,8 @@ impl<'tcx> LateLintPass<'tcx> for NonShorthandFieldPatterns {
                         == Some(cx.tcx.field_index(fieldpat.hir_id, cx.typeck_results()))
                     {
                         cx.struct_span_lint(NON_SHORTHAND_FIELD_PATTERNS, fieldpat.span, |lint| {
-                            let binding = match binding_annot {
-                                hir::BindingAnnotation::Unannotated => None,
-                                hir::BindingAnnotation::Mutable => Some("mut"),
-                                hir::BindingAnnotation::Ref => Some("ref"),
-                                hir::BindingAnnotation::RefMut => Some("ref mut"),
-                            };
-                            let suggested_ident = if let Some(binding) = binding {
-                                format!("{} {}", binding, ident)
-                            } else {
-                                ident.to_string()
-                            };
+                            let suggested_ident =
+                                format!("{}{}", binding_annot.prefix_str(), ident);
                             lint.build(fluent::lint::builtin_non_shorthand_field_patterns)
                                 .set_arg("ident", ident.clone())
                                 .span_suggestion(
@@ -616,7 +606,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
                 // Issue #11592: traits are always considered exported, even when private.
                 if cx.tcx.visibility(it.def_id)
                     == ty::Visibility::Restricted(
-                        cx.tcx.parent_module_from_def_id(it.def_id).to_def_id(),
+                        cx.tcx.parent_module_from_def_id(it.def_id.def_id).to_def_id(),
                     )
                 {
                     return;
@@ -637,13 +627,13 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
 
         let (article, desc) = cx.tcx.article_and_description(it.def_id.to_def_id());
 
-        self.check_missing_docs_attrs(cx, it.def_id, article, desc);
+        self.check_missing_docs_attrs(cx, it.def_id.def_id, article, desc);
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'_>, trait_item: &hir::TraitItem<'_>) {
         let (article, desc) = cx.tcx.article_and_description(trait_item.def_id.to_def_id());
 
-        self.check_missing_docs_attrs(cx, trait_item.def_id, article, desc);
+        self.check_missing_docs_attrs(cx, trait_item.def_id.def_id, article, desc);
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) {
@@ -671,12 +661,12 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
         }
 
         let (article, desc) = cx.tcx.article_and_description(impl_item.def_id.to_def_id());
-        self.check_missing_docs_attrs(cx, impl_item.def_id, article, desc);
+        self.check_missing_docs_attrs(cx, impl_item.def_id.def_id, article, desc);
     }
 
     fn check_foreign_item(&mut self, cx: &LateContext<'_>, foreign_item: &hir::ForeignItem<'_>) {
         let (article, desc) = cx.tcx.article_and_description(foreign_item.def_id.to_def_id());
-        self.check_missing_docs_attrs(cx, foreign_item.def_id, article, desc);
+        self.check_missing_docs_attrs(cx, foreign_item.def_id.def_id, article, desc);
     }
 
     fn check_field_def(&mut self, cx: &LateContext<'_>, sf: &hir::FieldDef<'_>) {
@@ -729,7 +719,7 @@ declare_lint_pass!(MissingCopyImplementations => [MISSING_COPY_IMPLEMENTATIONS])
 
 impl<'tcx> LateLintPass<'tcx> for MissingCopyImplementations {
     fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
-        if !cx.access_levels.is_reachable(item.def_id) {
+        if !cx.access_levels.is_reachable(item.def_id.def_id) {
             return;
         }
         let (def, ty) = match item.kind {
@@ -819,7 +809,7 @@ impl_lint_pass!(MissingDebugImplementations => [MISSING_DEBUG_IMPLEMENTATIONS]);
 
 impl<'tcx> LateLintPass<'tcx> for MissingDebugImplementations {
     fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
-        if !cx.access_levels.is_reachable(item.def_id) {
+        if !cx.access_levels.is_reachable(item.def_id.def_id) {
             return;
         }
 
@@ -846,7 +836,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDebugImplementations {
             debug!("{:?}", self.impling_types);
         }
 
-        if !self.impling_types.as_ref().unwrap().contains(&item.def_id) {
+        if !self.impling_types.as_ref().unwrap().contains(&item.def_id.def_id) {
             cx.struct_span_lint(MISSING_DEBUG_IMPLEMENTATIONS, item.span, |lint| {
                 lint.build(fluent::lint::builtin_missing_debug_impl)
                     .set_arg("debug", cx.tcx.def_path_str(debug))
@@ -1216,7 +1206,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidNoMangleItems {
                             check_no_mangle_on_generic_fn(
                                 no_mangle_attr,
                                 Some(generics),
-                                cx.tcx.hir().get_generics(it.id.def_id).unwrap(),
+                                cx.tcx.hir().get_generics(it.id.def_id.def_id).unwrap(),
                                 it.span,
                             );
                         }
@@ -1399,11 +1389,11 @@ impl<'tcx> LateLintPass<'tcx> for UnreachablePub {
         if let hir::ItemKind::Use(_, hir::UseKind::ListStem) = &item.kind {
             return;
         }
-        self.perform_lint(cx, "item", item.def_id, item.vis_span, true);
+        self.perform_lint(cx, "item", item.def_id.def_id, item.vis_span, true);
     }
 
     fn check_foreign_item(&mut self, cx: &LateContext<'_>, foreign_item: &hir::ForeignItem<'tcx>) {
-        self.perform_lint(cx, "item", foreign_item.def_id, foreign_item.vis_span, true);
+        self.perform_lint(cx, "item", foreign_item.def_id.def_id, foreign_item.vis_span, true);
     }
 
     fn check_field_def(&mut self, cx: &LateContext<'_>, field: &hir::FieldDef<'_>) {
@@ -1414,7 +1404,7 @@ impl<'tcx> LateLintPass<'tcx> for UnreachablePub {
     fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) {
         // Only lint inherent impl items.
         if cx.tcx.associated_item(impl_item.def_id).trait_item_def_id.is_none() {
-            self.perform_lint(cx, "item", impl_item.def_id, impl_item.vis_span, false);
+            self.perform_lint(cx, "item", impl_item.def_id.def_id, impl_item.vis_span, false);
         }
     }
 }
@@ -1477,7 +1467,7 @@ impl TypeAliasBounds {
                 if TypeAliasBounds::is_type_variable_assoc(qpath) {
                     self.err.span_help(span, fluent::lint::builtin_type_alias_bounds_help);
                 }
-                intravisit::walk_qpath(self, qpath, id, span)
+                intravisit::walk_qpath(self, qpath, id)
             }
         }
 
@@ -1851,7 +1841,7 @@ declare_lint! {
 }
 
 pub struct UnnameableTestItems {
-    boundary: Option<LocalDefId>, // Id of the item under which things are not nameable
+    boundary: Option<hir::OwnerId>, // Id of the item under which things are not nameable
     items_nameable: bool,
 }
 
@@ -2010,7 +2000,7 @@ impl KeywordIdents {
 }
 
 impl EarlyLintPass for KeywordIdents {
-    fn check_mac_def(&mut self, cx: &EarlyContext<'_>, mac_def: &ast::MacroDef, _id: ast::NodeId) {
+    fn check_mac_def(&mut self, cx: &EarlyContext<'_>, mac_def: &ast::MacroDef) {
         self.check_tokens(cx, mac_def.body.inner_tokens());
     }
     fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &ast::MacCall) {
@@ -2148,7 +2138,7 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
         use rustc_middle::middle::resolve_lifetime::Region;
 
-        let def_id = item.def_id;
+        let def_id = item.def_id.def_id;
         if let hir::ItemKind::Struct(_, ref hir_generics)
         | hir::ItemKind::Enum(_, ref hir_generics)
         | hir::ItemKind::Union(_, ref hir_generics) = item.kind
@@ -2413,13 +2403,13 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
                         _ => {}
                     }
                 }
-            } else if let hir::ExprKind::MethodCall(_, ref args, _) = expr.kind {
+            } else if let hir::ExprKind::MethodCall(_, receiver, ..) = expr.kind {
                 // Find problematic calls to `MaybeUninit::assume_init`.
                 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?;
                 if cx.tcx.is_diagnostic_item(sym::assume_init, def_id) {
                     // This is a call to *some* method named `assume_init`.
                     // See if the `self` parameter is one of the dangerous constructors.
-                    if let hir::ExprKind::Call(ref path_expr, _) = args[0].kind {
+                    if let hir::ExprKind::Call(ref path_expr, _) = receiver.kind {
                         if let hir::ExprKind::Path(ref qpath) = path_expr.kind {
                             let def_id = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id()?;
                             match cx.tcx.get_diagnostic_name(def_id) {
@@ -3173,3 +3163,117 @@ impl<'tcx> LateLintPass<'tcx> for NamedAsmLabels {
         }
     }
 }
+
+declare_lint! {
+    /// The `special_module_name` lint detects module
+    /// declarations for files that have a special meaning.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,compile_fail
+    /// mod lib;
+    ///
+    /// fn main() {
+    ///     lib::run();
+    /// }
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// Cargo recognizes `lib.rs` and `main.rs` as the root of a
+    /// library or binary crate, so declaring them as modules
+    /// will lead to miscompilation of the crate unless configured
+    /// explicitly.
+    ///
+    /// To access a library from a binary target within the same crate,
+    /// use `your_crate_name::` as the path path instead of `lib::`:
+    ///
+    /// ```rust,compile_fail
+    /// // bar/src/lib.rs
+    /// fn run() {
+    ///     // ...
+    /// }
+    ///
+    /// // bar/src/main.rs
+    /// fn main() {
+    ///     bar::run();
+    /// }
+    /// ```
+    ///
+    /// Binary targets cannot be used as libraries and so declaring
+    /// one as a module is not allowed.
+    pub SPECIAL_MODULE_NAME,
+    Warn,
+    "module declarations for files with a special meaning",
+}
+
+declare_lint_pass!(SpecialModuleName => [SPECIAL_MODULE_NAME]);
+
+impl EarlyLintPass for SpecialModuleName {
+    fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &ast::Crate) {
+        for item in &krate.items {
+            if let ast::ItemKind::Mod(
+                _,
+                ast::ModKind::Unloaded | ast::ModKind::Loaded(_, ast::Inline::No, _),
+            ) = item.kind
+            {
+                if item.attrs.iter().any(|a| a.has_name(sym::path)) {
+                    continue;
+                }
+
+                match item.ident.name.as_str() {
+                    "lib" => cx.struct_span_lint(SPECIAL_MODULE_NAME, item.span, |lint| {
+                        lint.build("found module declaration for lib.rs")
+                            .note("lib.rs is the root of this crate's library target")
+                            .help("to refer to it from other targets, use the library's name as the path")
+                            .emit()
+                    }),
+                    "main" => cx.struct_span_lint(SPECIAL_MODULE_NAME, item.span, |lint| {
+                        lint.build("found module declaration for main.rs")
+                            .note("a binary crate cannot be used as library")
+                            .emit()
+                    }),
+                    _ => continue
+                }
+            }
+        }
+    }
+}
+
+pub use rustc_session::lint::builtin::UNEXPECTED_CFGS;
+
+declare_lint_pass!(UnexpectedCfgs => [UNEXPECTED_CFGS]);
+
+impl EarlyLintPass for UnexpectedCfgs {
+    fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) {
+        let cfg = &cx.sess().parse_sess.config;
+        let check_cfg = &cx.sess().parse_sess.check_config;
+        for &(name, value) in cfg {
+            if let Some(names_valid) = &check_cfg.names_valid {
+                if !names_valid.contains(&name) {
+                    cx.lookup(UNEXPECTED_CFGS, None::<MultiSpan>, |diag| {
+                        diag.build(fluent::lint::builtin_unexpected_cli_config_name)
+                            .help(fluent::lint::help)
+                            .set_arg("name", name)
+                            .emit();
+                    });
+                }
+            }
+            if let Some(value) = value {
+                if let Some(values) = &check_cfg.values_valid.get(&name) {
+                    if !values.contains(&value) {
+                        cx.lookup(UNEXPECTED_CFGS, None::<MultiSpan>, |diag| {
+                            diag.build(fluent::lint::builtin_unexpected_cli_config_value)
+                                .help(fluent::lint::help)
+                                .set_arg("name", name)
+                                .set_arg("value", value)
+                                .emit();
+                        });
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index 002bba4759be..cbab56f2066f 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -45,12 +45,15 @@ use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::{BytePos, Span};
 use rustc_target::abi;
-use tracing::debug;
 
 use std::cell::Cell;
 use std::iter;
 use std::slice;
 
+type EarlyLintPassFactory = dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync;
+type LateLintPassFactory =
+    dyn for<'tcx> Fn(TyCtxt<'tcx>) -> LateLintPassObject<'tcx> + sync::Send + sync::Sync;
+
 /// Information about the registered lints.
 ///
 /// This is basically the subset of `Context` that we can
@@ -65,11 +68,11 @@ pub struct LintStore {
     /// interior mutability, we don't enforce this (and lints should, in theory,
     /// be compatible with being constructed more than once, though not
     /// necessarily in a sane manner. This is safe though.)
-    pub pre_expansion_passes: Vec<Box<dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync>>,
-    pub early_passes: Vec<Box<dyn Fn() -> EarlyLintPassObject + sync::Send + sync::Sync>>,
-    pub late_passes: Vec<Box<dyn Fn() -> LateLintPassObject + sync::Send + sync::Sync>>,
+    pub pre_expansion_passes: Vec<Box<EarlyLintPassFactory>>,
+    pub early_passes: Vec<Box<EarlyLintPassFactory>>,
+    pub late_passes: Vec<Box<LateLintPassFactory>>,
     /// This is unique in that we construct them per-module, so not once.
-    pub late_module_passes: Vec<Box<dyn Fn() -> LateLintPassObject + sync::Send + sync::Sync>>,
+    pub late_module_passes: Vec<Box<LateLintPassFactory>>,
 
     /// Lints indexed by name.
     by_name: FxHashMap<String, TargetLint>,
@@ -187,14 +190,20 @@ impl LintStore {
 
     pub fn register_late_pass(
         &mut self,
-        pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync,
+        pass: impl for<'tcx> Fn(TyCtxt<'tcx>) -> LateLintPassObject<'tcx>
+        + 'static
+        + sync::Send
+        + sync::Sync,
     ) {
         self.late_passes.push(Box::new(pass));
     }
 
     pub fn register_late_mod_pass(
         &mut self,
-        pass: impl Fn() -> LateLintPassObject + 'static + sync::Send + sync::Sync,
+        pass: impl for<'tcx> Fn(TyCtxt<'tcx>) -> LateLintPassObject<'tcx>
+        + 'static
+        + sync::Send
+        + sync::Sync,
     ) {
         self.late_module_passes.push(Box::new(pass));
     }
@@ -417,7 +426,7 @@ impl LintStore {
                     None => {
                         // 1. The tool is currently running, so this lint really doesn't exist.
                         // FIXME: should this handle tools that never register a lint, like rustfmt?
-                        tracing::debug!("lints={:?}", self.by_name.keys().collect::<Vec<_>>());
+                        debug!("lints={:?}", self.by_name.keys().collect::<Vec<_>>());
                         let tool_prefix = format!("{}::", tool_name);
                         return if self.by_name.keys().any(|lint| lint.starts_with(&tool_prefix)) {
                             self.no_lint_suggestion(&complete_name)
@@ -510,7 +519,7 @@ impl LintStore {
                 CheckLintNameResult::Tool(Err((Some(slice::from_ref(id)), complete_name)))
             }
             Some(other) => {
-                tracing::debug!("got renamed lint {:?}", other);
+                debug!("got renamed lint {:?}", other);
                 CheckLintNameResult::NoLint(None)
             }
         }
@@ -559,7 +568,7 @@ pub trait LintPassObject: Sized {}
 
 impl LintPassObject for EarlyLintPassObject {}
 
-impl LintPassObject for LateLintPassObject {}
+impl LintPassObject for LateLintPassObject<'_> {}
 
 pub trait LintContext: Sized {
     type PassObject: LintPassObject;
@@ -843,7 +852,7 @@ pub trait LintContext: Sized {
                     if let Some(positional_arg_to_replace) = position_sp_to_replace {
                         let name = if is_formatting_arg { named_arg_name + "$" } else { named_arg_name };
                         let span_to_replace = if let Ok(positional_arg_content) =
-                            self.sess().source_map().span_to_snippet(positional_arg_to_replace) && positional_arg_content.starts_with(":") {
+                            self.sess().source_map().span_to_snippet(positional_arg_to_replace) && positional_arg_content.starts_with(':') {
                             positional_arg_to_replace.shrink_to_lo()
                         } else {
                             positional_arg_to_replace
@@ -950,8 +959,8 @@ impl<'a> EarlyContext<'a> {
     }
 }
 
-impl LintContext for LateContext<'_> {
-    type PassObject = LateLintPassObject;
+impl<'tcx> LintContext for LateContext<'tcx> {
+    type PassObject = LateLintPassObject<'tcx>;
 
     /// Gets the overall compiler `Session` object.
     fn sess(&self) -> &Session {
@@ -1039,7 +1048,7 @@ impl<'tcx> LateContext<'tcx> {
                 .filter(|typeck_results| typeck_results.hir_owner == id.owner)
                 .or_else(|| {
                     if self.tcx.has_typeck_results(id.owner.to_def_id()) {
-                        Some(self.tcx.typeck(id.owner))
+                        Some(self.tcx.typeck(id.owner.def_id))
                     } else {
                         None
                     }
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index cdb5b3c4284a..96ecd79a69cf 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/compiler/rustc_lint/src/early.rs
@@ -26,7 +26,6 @@ use rustc_span::symbol::Ident;
 use rustc_span::Span;
 
 use std::slice;
-use tracing::debug;
 
 macro_rules! run_early_pass { ($cx:expr, $f:ident, $($args:expr),*) => ({
     $cx.pass.$f(&$cx.context, $($args),*);
@@ -148,7 +147,7 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
     fn visit_fn(&mut self, fk: ast_visit::FnKind<'a>, span: Span, id: ast::NodeId) {
         run_early_pass!(self, check_fn, fk, span, id);
         self.check_id(id);
-        ast_visit::walk_fn(self, fk, span);
+        ast_visit::walk_fn(self, fk);
 
         // Explicitly check for lints associated with 'closure_id', since
         // it does not have a corresponding AST node
@@ -267,9 +266,9 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
         ast_visit::walk_path(self, p);
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, s: &'a ast::PathSegment) {
+    fn visit_path_segment(&mut self, s: &'a ast::PathSegment) {
         self.check_id(s.id);
-        ast_visit::walk_path_segment(self, path_span, s);
+        ast_visit::walk_path_segment(self, s);
     }
 
     fn visit_attribute(&mut self, attr: &'a ast::Attribute) {
@@ -277,7 +276,7 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
     }
 
     fn visit_mac_def(&mut self, mac: &'a ast::MacroDef, id: ast::NodeId) {
-        run_early_pass!(self, check_mac_def, mac, id);
+        run_early_pass!(self, check_mac_def, mac);
         self.check_id(id);
     }
 
diff --git a/compiler/rustc_lint/src/errors.rs b/compiler/rustc_lint/src/errors.rs
index 606d8bda8aaf..880f3fbd00e6 100644
--- a/compiler/rustc_lint/src/errors.rs
+++ b/compiler/rustc_lint/src/errors.rs
@@ -1,9 +1,9 @@
-use rustc_errors::{fluent, AddSubdiagnostic, ErrorGuaranteed};
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
-use rustc_session::{lint::Level, parse::ParseSess, SessionDiagnostic};
+use rustc_errors::{fluent, AddToDiagnostic, ErrorGuaranteed, Handler, IntoDiagnostic};
+use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_session::lint::Level;
 use rustc_span::{Span, Symbol};
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::overruled_attribute, code = "E0453")]
 pub struct OverruledAttribute {
     #[primary_span]
@@ -22,7 +22,7 @@ pub enum OverruledAttributeSub {
     CommandLineSource,
 }
 
-impl AddSubdiagnostic for OverruledAttributeSub {
+impl AddToDiagnostic for OverruledAttributeSub {
     fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
         match self {
             OverruledAttributeSub::DefaultSource { id } => {
@@ -42,7 +42,7 @@ impl AddSubdiagnostic for OverruledAttributeSub {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::malformed_attribute, code = "E0452")]
 pub struct MalformedAttribute {
     #[primary_span]
@@ -51,7 +51,7 @@ pub struct MalformedAttribute {
     pub sub: MalformedAttributeSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum MalformedAttributeSub {
     #[label(lint::bad_attribute_argument)]
     BadAttributeArgument(#[primary_span] Span),
@@ -61,7 +61,7 @@ pub enum MalformedAttributeSub {
     ReasonMustComeLast(#[primary_span] Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::unknown_tool_in_scoped_lint, code = "E0710")]
 pub struct UnknownToolInScopedLint {
     #[primary_span]
@@ -72,7 +72,7 @@ pub struct UnknownToolInScopedLint {
     pub is_nightly_build: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::builtin_ellipsis_inclusive_range_patterns, code = "E0783")]
 pub struct BuiltinEllpisisInclusiveRangePatterns {
     #[primary_span]
@@ -87,7 +87,7 @@ pub struct RequestedLevel {
     pub lint_name: String,
 }
 
-impl AddSubdiagnostic for RequestedLevel {
+impl AddToDiagnostic for RequestedLevel {
     fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
         diag.note(fluent::lint::requested_level);
         diag.set_arg(
@@ -107,7 +107,7 @@ impl AddSubdiagnostic for RequestedLevel {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::unsupported_group, code = "E0602")]
 pub struct UnsupportedGroup {
     pub lint_group: String,
@@ -119,12 +119,12 @@ pub struct CheckNameUnknown {
     pub sub: RequestedLevel,
 }
 
-impl SessionDiagnostic<'_> for CheckNameUnknown {
+impl IntoDiagnostic<'_> for CheckNameUnknown {
     fn into_diagnostic(
         self,
-        sess: &ParseSess,
+        handler: &Handler,
     ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = sess.struct_err(fluent::lint::check_name_unknown);
+        let mut diag = handler.struct_err(fluent::lint::check_name_unknown);
         diag.code(rustc_errors::error_code!(E0602));
         if let Some(suggestion) = self.suggestion {
             diag.help(fluent::lint::help);
@@ -136,7 +136,7 @@ impl SessionDiagnostic<'_> for CheckNameUnknown {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::check_name_unknown_tool, code = "E0602")]
 pub struct CheckNameUnknownTool {
     pub tool_name: Symbol,
@@ -144,7 +144,7 @@ pub struct CheckNameUnknownTool {
     pub sub: RequestedLevel,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::check_name_warning)]
 pub struct CheckNameWarning {
     pub msg: String,
@@ -152,7 +152,7 @@ pub struct CheckNameWarning {
     pub sub: RequestedLevel,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(lint::check_name_deprecated)]
 pub struct CheckNameDeprecated {
     pub lint_name: String,
diff --git a/compiler/rustc_lint/src/internal.rs b/compiler/rustc_lint/src/internal.rs
index c26d7824758e..d8a03024d132 100644
--- a/compiler/rustc_lint/src/internal.rs
+++ b/compiler/rustc_lint/src/internal.rs
@@ -12,7 +12,6 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
-use tracing::debug;
 
 declare_tool_lint! {
     pub rustc::DEFAULT_HASH_TYPES,
@@ -52,7 +51,7 @@ fn typeck_results_of_method_fn<'tcx>(
     expr: &Expr<'_>,
 ) -> Option<(Span, DefId, ty::subst::SubstsRef<'tcx>)> {
     match expr.kind {
-        ExprKind::MethodCall(segment, _, _)
+        ExprKind::MethodCall(segment, ..)
             if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) =>
         {
             Some((segment.ident.span, def_id, cx.typeck_results().node_substs(expr.hir_id)))
@@ -119,8 +118,7 @@ impl<'tcx> LateLintPass<'tcx> for TyTyKind {
         _: rustc_hir::HirId,
     ) {
         if let Some(segment) = path.segments.iter().nth_back(1)
-        && let Some(res) = &segment.res
-        && lint_ty_kind_usage(cx, res)
+        && lint_ty_kind_usage(cx, &segment.res)
         {
             let span = path.span.with_hi(
                 segment.args.map_or(segment.ident.span, |a| a.span_ext).hi()
@@ -374,7 +372,7 @@ declare_tool_lint! {
 declare_tool_lint! {
     pub rustc::DIAGNOSTIC_OUTSIDE_OF_IMPL,
     Allow,
-    "prevent creation of diagnostics outside of `SessionDiagnostic`/`AddSubdiagnostic` impls",
+    "prevent creation of diagnostics outside of `IntoDiagnostic`/`AddToDiagnostic` impls",
     report_in_external_macro: true
 }
 
@@ -393,21 +391,27 @@ impl LateLintPass<'_> for Diagnostics {
             return;
         }
 
+        let mut found_parent_with_attr = false;
         let mut found_impl = false;
-        for (_, parent) in cx.tcx.hir().parent_iter(expr.hir_id) {
+        for (hir_id, parent) in cx.tcx.hir().parent_iter(expr.hir_id) {
+            if let Some(owner_did) = hir_id.as_owner() {
+                found_parent_with_attr = found_parent_with_attr
+                    || cx.tcx.has_attr(owner_did.to_def_id(), sym::rustc_lint_diagnostics);
+            }
+
             debug!(?parent);
             if let Node::Item(Item { kind: ItemKind::Impl(impl_), .. }) = parent &&
                 let Impl { of_trait: Some(of_trait), .. } = impl_ &&
                 let Some(def_id) = of_trait.trait_def_id() &&
                 let Some(name) = cx.tcx.get_diagnostic_name(def_id) &&
-                matches!(name, sym::SessionDiagnostic | sym::AddSubdiagnostic | sym::DecorateLint)
+                matches!(name, sym::IntoDiagnostic | sym::AddToDiagnostic | sym::DecorateLint)
             {
                 found_impl = true;
                 break;
             }
         }
         debug!(?found_impl);
-        if !found_impl {
+        if !found_parent_with_attr && !found_impl {
             cx.struct_span_lint(DIAGNOSTIC_OUTSIDE_OF_IMPL, span, |lint| {
                 lint.build(fluent::lint::diag_out_of_impl).emit();
             })
@@ -425,7 +429,7 @@ impl LateLintPass<'_> for Diagnostics {
             }
         }
         debug!(?found_diagnostic_message);
-        if !found_diagnostic_message {
+        if !found_parent_with_attr && !found_diagnostic_message {
             cx.struct_span_lint(UNTRANSLATABLE_DIAGNOSTIC, span, |lint| {
                 lint.build(fluent::lint::untranslatable_diag).emit();
             })
diff --git a/compiler/rustc_lint/src/late.rs b/compiler/rustc_lint/src/late.rs
index 5188ac633d39..da6f1c5eeccf 100644
--- a/compiler/rustc_lint/src/late.rs
+++ b/compiler/rustc_lint/src/late.rs
@@ -29,7 +29,6 @@ use rustc_span::Span;
 use std::any::Any;
 use std::cell::Cell;
 use std::slice;
-use tracing::debug;
 
 /// Extract the `LintStore` from the query context.
 /// This function exists because we've erased `LintStore` as `dyn Any` in the context.
@@ -77,8 +76,8 @@ impl<'tcx, T: LateLintPass<'tcx>> LateContextAndPass<'tcx, T> {
         self.context.param_env = old_param_env;
     }
 
-    fn process_mod(&mut self, m: &'tcx hir::Mod<'tcx>, s: Span, n: hir::HirId) {
-        lint_callback!(self, check_mod, m, s, n);
+    fn process_mod(&mut self, m: &'tcx hir::Mod<'tcx>, n: hir::HirId) {
+        lint_callback!(self, check_mod, m, n);
         hir_visit::walk_mod(self, m, n);
     }
 }
@@ -188,7 +187,7 @@ impl<'tcx, T: LateLintPass<'tcx>> hir_visit::Visitor<'tcx> for LateContextAndPas
         let old_cached_typeck_results = self.context.cached_typeck_results.take();
         let body = self.context.tcx.hir().body(body_id);
         lint_callback!(self, check_fn, fk, decl, body, span, id);
-        hir_visit::walk_fn(self, fk, decl, body_id, span, id);
+        hir_visit::walk_fn(self, fk, decl, body_id, id);
         self.context.enclosing_body = old_enclosing_body;
         self.context.cached_typeck_results.set(old_cached_typeck_results);
     }
@@ -221,9 +220,9 @@ impl<'tcx, T: LateLintPass<'tcx>> hir_visit::Visitor<'tcx> for LateContextAndPas
         hir_visit::walk_inf(self, inf);
     }
 
-    fn visit_mod(&mut self, m: &'tcx hir::Mod<'tcx>, s: Span, n: hir::HirId) {
+    fn visit_mod(&mut self, m: &'tcx hir::Mod<'tcx>, _: Span, n: hir::HirId) {
         if !self.context.only_module {
-            self.process_mod(m, s, n);
+            self.process_mod(m, n);
         }
     }
 
@@ -259,13 +258,9 @@ impl<'tcx, T: LateLintPass<'tcx>> hir_visit::Visitor<'tcx> for LateContextAndPas
         hir_visit::walk_where_predicate(self, p);
     }
 
-    fn visit_poly_trait_ref(
-        &mut self,
-        t: &'tcx hir::PolyTraitRef<'tcx>,
-        m: hir::TraitBoundModifier,
-    ) {
-        lint_callback!(self, check_poly_trait_ref, t, m);
-        hir_visit::walk_poly_trait_ref(self, t, m);
+    fn visit_poly_trait_ref(&mut self, t: &'tcx hir::PolyTraitRef<'tcx>) {
+        lint_callback!(self, check_poly_trait_ref, t);
+        hir_visit::walk_poly_trait_ref(self, t);
     }
 
     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
@@ -307,12 +302,12 @@ impl<'tcx, T: LateLintPass<'tcx>> hir_visit::Visitor<'tcx> for LateContextAndPas
     }
 }
 
-struct LateLintPassObjects<'a> {
-    lints: &'a mut [LateLintPassObject],
+struct LateLintPassObjects<'a, 'tcx> {
+    lints: &'a mut [LateLintPassObject<'tcx>],
 }
 
 #[allow(rustc::lint_pass_impl_without_macro)]
-impl LintPass for LateLintPassObjects<'_> {
+impl LintPass for LateLintPassObjects<'_, '_> {
     fn name(&self) -> &'static str {
         panic!()
     }
@@ -330,7 +325,7 @@ macro_rules! expand_late_lint_pass_impl_methods {
 
 macro_rules! late_lint_pass_impl {
     ([], [$hir:tt], $methods:tt) => {
-        impl<$hir> LateLintPass<$hir> for LateLintPassObjects<'_> {
+        impl<$hir> LateLintPass<$hir> for LateLintPassObjects<'_, $hir> {
             expand_late_lint_pass_impl_methods!([$hir], $methods);
         }
     };
@@ -359,8 +354,8 @@ fn late_lint_mod_pass<'tcx, T: LateLintPass<'tcx>>(
 
     let mut cx = LateContextAndPass { context, pass };
 
-    let (module, span, hir_id) = tcx.hir().get_module(module_def_id);
-    cx.process_mod(module, span, hir_id);
+    let (module, _span, hir_id) = tcx.hir().get_module(module_def_id);
+    cx.process_mod(module, hir_id);
 
     // Visit the crate attributes
     if hir_id == hir::CRATE_HIR_ID {
@@ -383,7 +378,7 @@ pub fn late_lint_mod<'tcx, T: LateLintPass<'tcx>>(
     late_lint_mod_pass(tcx, module_def_id, builtin_lints);
 
     let mut passes: Vec<_> =
-        unerased_lint_store(tcx).late_module_passes.iter().map(|pass| (pass)()).collect();
+        unerased_lint_store(tcx).late_module_passes.iter().map(|pass| (pass)(tcx)).collect();
 
     if !passes.is_empty() {
         late_lint_mod_pass(tcx, module_def_id, LateLintPassObjects { lints: &mut passes[..] });
@@ -419,7 +414,8 @@ fn late_lint_pass_crate<'tcx, T: LateLintPass<'tcx>>(tcx: TyCtxt<'tcx>, pass: T)
 }
 
 fn late_lint_crate<'tcx, T: LateLintPass<'tcx>>(tcx: TyCtxt<'tcx>, builtin_lints: T) {
-    let mut passes = unerased_lint_store(tcx).late_passes.iter().map(|p| (p)()).collect::<Vec<_>>();
+    let mut passes =
+        unerased_lint_store(tcx).late_passes.iter().map(|p| (p)(tcx)).collect::<Vec<_>>();
 
     if !tcx.sess.opts.unstable_opts.no_interleave_lints {
         if !passes.is_empty() {
@@ -435,7 +431,7 @@ fn late_lint_crate<'tcx, T: LateLintPass<'tcx>>(tcx: TyCtxt<'tcx>, builtin_lints
         }
 
         let mut passes: Vec<_> =
-            unerased_lint_store(tcx).late_module_passes.iter().map(|pass| (pass)()).collect();
+            unerased_lint_store(tcx).late_module_passes.iter().map(|pass| (pass)(tcx)).collect();
 
         for pass in &mut passes {
             tcx.sess.prof.extra_verbose_generic_activity("run_late_module_lint", pass.name()).run(
diff --git a/compiler/rustc_lint/src/let_underscore.rs b/compiler/rustc_lint/src/let_underscore.rs
new file mode 100644
index 000000000000..7e885e6c51aa
--- /dev/null
+++ b/compiler/rustc_lint/src/let_underscore.rs
@@ -0,0 +1,175 @@
+use crate::{LateContext, LateLintPass, LintContext};
+use rustc_errors::{Applicability, LintDiagnosticBuilder, MultiSpan};
+use rustc_hir as hir;
+use rustc_middle::ty;
+use rustc_span::Symbol;
+
+declare_lint! {
+    /// The `let_underscore_drop` lint checks for statements which don't bind
+    /// an expression which has a non-trivial Drop implementation to anything,
+    /// causing the expression to be dropped immediately instead of at end of
+    /// scope.
+    ///
+    /// ### Example
+    /// ```
+    /// struct SomeStruct;
+    /// impl Drop for SomeStruct {
+    ///     fn drop(&mut self) {
+    ///         println!("Dropping SomeStruct");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///    #[warn(let_underscore_drop)]
+    ///     // SomeStuct is dropped immediately instead of at end of scope,
+    ///     // so "Dropping SomeStruct" is printed before "end of main".
+    ///     // The order of prints would be reversed if SomeStruct was bound to
+    ///     // a name (such as "_foo").
+    ///     let _ = SomeStruct;
+    ///     println!("end of main");
+    /// }
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// Statements which assign an expression to an underscore causes the
+    /// expression to immediately drop instead of extending the expression's
+    /// lifetime to the end of the scope. This is usually unintended,
+    /// especially for types like `MutexGuard`, which are typically used to
+    /// lock a mutex for the duration of an entire scope.
+    ///
+    /// If you want to extend the expression's lifetime to the end of the scope,
+    /// assign an underscore-prefixed name (such as `_foo`) to the expression.
+    /// If you do actually want to drop the expression immediately, then
+    /// calling `std::mem::drop` on the expression is clearer and helps convey
+    /// intent.
+    pub LET_UNDERSCORE_DROP,
+    Allow,
+    "non-binding let on a type that implements `Drop`"
+}
+
+declare_lint! {
+    /// The `let_underscore_lock` lint checks for statements which don't bind
+    /// a mutex to anything, causing the lock to be released immediately instead
+    /// of at end of scope, which is typically incorrect.
+    ///
+    /// ### Example
+    /// ```compile_fail
+    /// use std::sync::{Arc, Mutex};
+    /// use std::thread;
+    /// let data = Arc::new(Mutex::new(0));
+    ///
+    /// thread::spawn(move || {
+    ///     // The lock is immediately released instead of at the end of the
+    ///     // scope, which is probably not intended.
+    ///     let _ = data.lock().unwrap();
+    ///     println!("doing some work");
+    ///     let mut lock = data.lock().unwrap();
+    ///     *lock += 1;
+    /// });
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// Statements which assign an expression to an underscore causes the
+    /// expression to immediately drop instead of extending the expression's
+    /// lifetime to the end of the scope. This is usually unintended,
+    /// especially for types like `MutexGuard`, which are typically used to
+    /// lock a mutex for the duration of an entire scope.
+    ///
+    /// If you want to extend the expression's lifetime to the end of the scope,
+    /// assign an underscore-prefixed name (such as `_foo`) to the expression.
+    /// If you do actually want to drop the expression immediately, then
+    /// calling `std::mem::drop` on the expression is clearer and helps convey
+    /// intent.
+    pub LET_UNDERSCORE_LOCK,
+    Deny,
+    "non-binding let on a synchronization lock"
+}
+
+declare_lint_pass!(LetUnderscore => [LET_UNDERSCORE_DROP, LET_UNDERSCORE_LOCK]);
+
+const SYNC_GUARD_SYMBOLS: [Symbol; 3] = [
+    rustc_span::sym::MutexGuard,
+    rustc_span::sym::RwLockReadGuard,
+    rustc_span::sym::RwLockWriteGuard,
+];
+
+impl<'tcx> LateLintPass<'tcx> for LetUnderscore {
+    fn check_local(&mut self, cx: &LateContext<'_>, local: &hir::Local<'_>) {
+        if !matches!(local.pat.kind, hir::PatKind::Wild) {
+            return;
+        }
+        if let Some(init) = local.init {
+            let init_ty = cx.typeck_results().expr_ty(init);
+            // If the type has a trivial Drop implementation, then it doesn't
+            // matter that we drop the value immediately.
+            if !init_ty.needs_drop(cx.tcx, cx.param_env) {
+                return;
+            }
+            let is_sync_lock = match init_ty.kind() {
+                ty::Adt(adt, _) => SYNC_GUARD_SYMBOLS
+                    .iter()
+                    .any(|guard_symbol| cx.tcx.is_diagnostic_item(*guard_symbol, adt.did())),
+                _ => false,
+            };
+
+            if is_sync_lock {
+                let mut span = MultiSpan::from_spans(vec![local.pat.span, init.span]);
+                span.push_span_label(
+                    local.pat.span,
+                    "this lock is not assigned to a binding and is immediately dropped".to_string(),
+                );
+                span.push_span_label(
+                    init.span,
+                    "this binding will immediately drop the value assigned to it".to_string(),
+                );
+                cx.struct_span_lint(LET_UNDERSCORE_LOCK, span, |lint| {
+                    build_and_emit_lint(
+                        lint,
+                        local,
+                        init.span,
+                        "non-binding let on a synchronization lock",
+                    )
+                })
+            } else {
+                cx.struct_span_lint(LET_UNDERSCORE_DROP, local.span, |lint| {
+                    build_and_emit_lint(
+                        lint,
+                        local,
+                        init.span,
+                        "non-binding let on a type that implements `Drop`",
+                    );
+                })
+            }
+        }
+    }
+}
+
+fn build_and_emit_lint(
+    lint: LintDiagnosticBuilder<'_, ()>,
+    local: &hir::Local<'_>,
+    init_span: rustc_span::Span,
+    msg: &str,
+) {
+    lint.build(msg)
+        .span_suggestion_verbose(
+            local.pat.span,
+            "consider binding to an unused variable to avoid immediately dropping the value",
+            "_unused",
+            Applicability::MachineApplicable,
+        )
+        .multipart_suggestion(
+            "consider immediately dropping the value",
+            vec![
+                (local.span.until(init_span), "drop(".to_string()),
+                (init_span.shrink_to_hi(), ")".to_string()),
+            ],
+            Applicability::MachineApplicable,
+        )
+        .emit();
+}
diff --git a/compiler/rustc_lint/src/levels.rs b/compiler/rustc_lint/src/levels.rs
index 89409b58f88b..1e16ac51e9e5 100644
--- a/compiler/rustc_lint/src/levels.rs
+++ b/compiler/rustc_lint/src/levels.rs
@@ -21,7 +21,6 @@ use rustc_session::parse::{add_feature_diagnostics, feature_err};
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use tracing::debug;
 
 use crate::errors::{
     MalformedAttribute, MalformedAttributeSub, OverruledAttribute, OverruledAttributeSub,
@@ -441,8 +440,10 @@ impl<'s> LintLevelsBuilder<'s> {
                                     sp,
                                     reason,
                                 );
-                                for id in ids {
-                                    self.insert_spec(*id, (level, src));
+                                for &id in ids {
+                                    if self.check_gated_lint(id, attr.span) {
+                                        self.insert_spec(id, (level, src));
+                                    }
                                 }
                                 if let Level::Expect(expect_id) = level {
                                     self.lint_expectations.push((
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index c3065e4a2d93..4408f68dd63f 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -34,7 +34,7 @@
 #![feature(iter_intersperse)]
 #![feature(iter_order_by)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![feature(min_specialization)]
 #![feature(never_type)]
 #![recursion_limit = "256"]
 
@@ -42,6 +42,8 @@
 extern crate rustc_middle;
 #[macro_use]
 extern crate rustc_session;
+#[macro_use]
+extern crate tracing;
 
 mod array_into_iter;
 pub mod builtin;
@@ -53,6 +55,7 @@ mod expect;
 pub mod hidden_unicode_codepoints;
 mod internal;
 mod late;
+mod let_underscore;
 mod levels;
 mod methods;
 mod non_ascii_idents;
@@ -84,6 +87,7 @@ use builtin::*;
 use enum_intrinsics_non_enums::EnumIntrinsicsNonEnums;
 use hidden_unicode_codepoints::*;
 use internal::*;
+use let_underscore::*;
 use methods::*;
 use non_ascii_idents::*;
 use non_fmt_panic::NonPanicFmt;
@@ -131,6 +135,7 @@ macro_rules! early_lint_passes {
                 UnusedBraces: UnusedBraces,
                 UnusedImportBraces: UnusedImportBraces,
                 UnsafeCode: UnsafeCode,
+                SpecialModuleName: SpecialModuleName,
                 AnonymousParameters: AnonymousParameters,
                 EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
                 NonCamelCaseTypes: NonCamelCaseTypes,
@@ -141,6 +146,7 @@ macro_rules! early_lint_passes {
                 IncompleteFeatures: IncompleteFeatures,
                 RedundantSemicolons: RedundantSemicolons,
                 UnusedDocComment: UnusedDocComment,
+                UnexpectedCfgs: UnexpectedCfgs,
             ]
         );
     };
@@ -186,6 +192,7 @@ macro_rules! late_lint_mod_passes {
                 VariantSizeDifferences: VariantSizeDifferences,
                 BoxPointers: BoxPointers,
                 PathStatements: PathStatements,
+                LetUnderscore: LetUnderscore,
                 // Depends on referenced function signatures in expressions
                 UnusedResults: UnusedResults,
                 NonUpperCaseGlobals: NonUpperCaseGlobals,
@@ -253,26 +260,41 @@ fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
         )
     }
 
-    macro_rules! register_pass {
+    macro_rules! register_early_pass {
         ($method:ident, $ty:ident, $constructor:expr) => {
             store.register_lints(&$ty::get_lints());
             store.$method(|| Box::new($constructor));
         };
     }
 
-    macro_rules! register_passes {
+    macro_rules! register_late_pass {
+        ($method:ident, $ty:ident, $constructor:expr) => {
+            store.register_lints(&$ty::get_lints());
+            store.$method(|_| Box::new($constructor));
+        };
+    }
+
+    macro_rules! register_early_passes {
         ($method:ident, [$($passes:ident: $constructor:expr,)*]) => (
             $(
-                register_pass!($method, $passes, $constructor);
+                register_early_pass!($method, $passes, $constructor);
+            )*
+        )
+    }
+
+    macro_rules! register_late_passes {
+        ($method:ident, [$($passes:ident: $constructor:expr,)*]) => (
+            $(
+                register_late_pass!($method, $passes, $constructor);
             )*
         )
     }
 
     if no_interleave_lints {
-        pre_expansion_lint_passes!(register_passes, register_pre_expansion_pass);
-        early_lint_passes!(register_passes, register_early_pass);
-        late_lint_passes!(register_passes, register_late_pass);
-        late_lint_mod_passes!(register_passes, register_late_mod_pass);
+        pre_expansion_lint_passes!(register_early_passes, register_pre_expansion_pass);
+        early_lint_passes!(register_early_passes, register_early_pass);
+        late_lint_passes!(register_late_passes, register_late_pass);
+        late_lint_mod_passes!(register_late_passes, register_late_mod_pass);
     } else {
         store.register_lints(&BuiltinCombinedPreExpansionLintPass::get_lints());
         store.register_lints(&BuiltinCombinedEarlyLintPass::get_lints());
@@ -312,6 +334,8 @@ fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
         REDUNDANT_SEMICOLONS
     );
 
+    add_lint_group!("let_underscore", LET_UNDERSCORE_DROP, LET_UNDERSCORE_LOCK);
+
     add_lint_group!(
         "rust_2018_idioms",
         BARE_TRAIT_OBJECTS,
@@ -501,19 +525,19 @@ fn register_internals(store: &mut LintStore) {
     store.register_lints(&LintPassImpl::get_lints());
     store.register_early_pass(|| Box::new(LintPassImpl));
     store.register_lints(&DefaultHashTypes::get_lints());
-    store.register_late_pass(|| Box::new(DefaultHashTypes));
+    store.register_late_pass(|_| Box::new(DefaultHashTypes));
     store.register_lints(&QueryStability::get_lints());
-    store.register_late_pass(|| Box::new(QueryStability));
+    store.register_late_pass(|_| Box::new(QueryStability));
     store.register_lints(&ExistingDocKeyword::get_lints());
-    store.register_late_pass(|| Box::new(ExistingDocKeyword));
+    store.register_late_pass(|_| Box::new(ExistingDocKeyword));
     store.register_lints(&TyTyKind::get_lints());
-    store.register_late_pass(|| Box::new(TyTyKind));
+    store.register_late_pass(|_| Box::new(TyTyKind));
     store.register_lints(&Diagnostics::get_lints());
-    store.register_late_pass(|| Box::new(Diagnostics));
+    store.register_late_pass(|_| Box::new(Diagnostics));
     store.register_lints(&BadOptAccess::get_lints());
-    store.register_late_pass(|| Box::new(BadOptAccess));
+    store.register_late_pass(|_| Box::new(BadOptAccess));
     store.register_lints(&PassByValue::get_lints());
-    store.register_late_pass(|| Box::new(PassByValue));
+    store.register_late_pass(|_| Box::new(PassByValue));
     // FIXME(davidtwco): deliberately do not include `UNTRANSLATABLE_DIAGNOSTIC` and
     // `DIAGNOSTIC_OUTSIDE_OF_IMPL` here because `-Wrustc::internal` is provided to every crate and
     // these lints will trigger all of the time - change this once migration to diagnostic structs
diff --git a/compiler/rustc_lint/src/methods.rs b/compiler/rustc_lint/src/methods.rs
index ff5a01749c19..5f7f03480c04 100644
--- a/compiler/rustc_lint/src/methods.rs
+++ b/compiler/rustc_lint/src/methods.rs
@@ -44,9 +44,13 @@ fn in_macro(span: Span) -> bool {
 
 fn first_method_call<'tcx>(
     expr: &'tcx Expr<'tcx>,
-) -> Option<(&'tcx PathSegment<'tcx>, &'tcx [Expr<'tcx>])> {
-    if let ExprKind::MethodCall(path, args, _) = &expr.kind {
-        if args.iter().any(|e| e.span.from_expansion()) { None } else { Some((path, *args)) }
+) -> Option<(&'tcx PathSegment<'tcx>, &'tcx Expr<'tcx>)> {
+    if let ExprKind::MethodCall(path, receiver, args, ..) = &expr.kind {
+        if args.iter().any(|e| e.span.from_expansion()) || receiver.span.from_expansion() {
+            None
+        } else {
+            Some((path, *receiver))
+        }
     } else {
         None
     }
@@ -59,15 +63,13 @@ impl<'tcx> LateLintPass<'tcx> for TemporaryCStringAsPtr {
         }
 
         match first_method_call(expr) {
-            Some((path, args)) if path.ident.name == sym::as_ptr => {
-                let unwrap_arg = &args[0];
+            Some((path, unwrap_arg)) if path.ident.name == sym::as_ptr => {
                 let as_ptr_span = path.ident.span;
                 match first_method_call(unwrap_arg) {
-                    Some((path, args))
+                    Some((path, receiver))
                         if path.ident.name == sym::unwrap || path.ident.name == sym::expect =>
                     {
-                        let source_arg = &args[0];
-                        lint_cstring_as_ptr(cx, as_ptr_span, source_arg, unwrap_arg);
+                        lint_cstring_as_ptr(cx, as_ptr_span, receiver, unwrap_arg);
                     }
                     _ => return,
                 }
diff --git a/compiler/rustc_lint/src/nonstandard_style.rs b/compiler/rustc_lint/src/nonstandard_style.rs
index 2868aabfa07e..768ad84838b1 100644
--- a/compiler/rustc_lint/src/nonstandard_style.rs
+++ b/compiler/rustc_lint/src/nonstandard_style.rs
@@ -327,13 +327,7 @@ impl NonSnakeCase {
 }
 
 impl<'tcx> LateLintPass<'tcx> for NonSnakeCase {
-    fn check_mod(
-        &mut self,
-        cx: &LateContext<'_>,
-        _: &'tcx hir::Mod<'tcx>,
-        _: Span,
-        id: hir::HirId,
-    ) {
+    fn check_mod(&mut self, cx: &LateContext<'_>, _: &'tcx hir::Mod<'tcx>, id: hir::HirId) {
         if id != hir::CRATE_HIR_ID {
             return;
         }
diff --git a/compiler/rustc_lint/src/noop_method_call.rs b/compiler/rustc_lint/src/noop_method_call.rs
index 11a752ff0970..d1449496d331 100644
--- a/compiler/rustc_lint/src/noop_method_call.rs
+++ b/compiler/rustc_lint/src/noop_method_call.rs
@@ -41,7 +41,7 @@ declare_lint_pass!(NoopMethodCall => [NOOP_METHOD_CALL]);
 impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         // We only care about method calls.
-        let ExprKind::MethodCall(call, elements, _) = &expr.kind else {
+        let ExprKind::MethodCall(call, receiver, ..) = &expr.kind else {
             return
         };
         // We only care about method calls corresponding to the `Clone`, `Deref` and `Borrow`
@@ -81,7 +81,6 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
         ) {
             return;
         }
-        let receiver = &elements[0];
         let receiver_ty = cx.typeck_results().expr_ty(receiver);
         let expr_ty = cx.typeck_results().expr_ty_adjusted(expr);
         if receiver_ty != expr_ty {
diff --git a/compiler/rustc_lint/src/passes.rs b/compiler/rustc_lint/src/passes.rs
index 90c554c2e040..1c6a057d1a85 100644
--- a/compiler/rustc_lint/src/passes.rs
+++ b/compiler/rustc_lint/src/passes.rs
@@ -16,7 +16,7 @@ macro_rules! late_lint_methods {
             fn check_body_post(a: &$hir hir::Body<$hir>);
             fn check_crate();
             fn check_crate_post();
-            fn check_mod(a: &$hir hir::Mod<$hir>, b: Span, c: hir::HirId);
+            fn check_mod(a: &$hir hir::Mod<$hir>, b: hir::HirId);
             fn check_foreign_item(a: &$hir hir::ForeignItem<$hir>);
             fn check_item(a: &$hir hir::Item<$hir>);
             fn check_item_post(a: &$hir hir::Item<$hir>);
@@ -31,7 +31,7 @@ macro_rules! late_lint_methods {
             fn check_ty(a: &$hir hir::Ty<$hir>);
             fn check_generic_param(a: &$hir hir::GenericParam<$hir>);
             fn check_generics(a: &$hir hir::Generics<$hir>);
-            fn check_poly_trait_ref(a: &$hir hir::PolyTraitRef<$hir>, b: hir::TraitBoundModifier);
+            fn check_poly_trait_ref(a: &$hir hir::PolyTraitRef<$hir>);
             fn check_fn(
                 a: rustc_hir::intravisit::FnKind<$hir>,
                 b: &$hir hir::FnDecl<$hir>,
@@ -162,7 +162,7 @@ macro_rules! early_lint_methods {
             fn check_impl_item(a: &ast::AssocItem);
             fn check_variant(a: &ast::Variant);
             fn check_attribute(a: &ast::Attribute);
-            fn check_mac_def(a: &ast::MacroDef, b: ast::NodeId);
+            fn check_mac_def(a: &ast::MacroDef);
             fn check_mac(a: &ast::MacCall);
 
             /// Called when entering a syntax node that can have lint attributes such
@@ -244,4 +244,4 @@ macro_rules! declare_combined_early_lint_pass {
 
 /// A lint pass boxed up as a trait object.
 pub type EarlyLintPassObject = Box<dyn EarlyLintPass + sync::Send + 'static>;
-pub type LateLintPassObject = Box<dyn for<'tcx> LateLintPass<'tcx> + sync::Send + 'static>;
+pub type LateLintPassObject<'tcx> = Box<dyn LateLintPass<'tcx> + sync::Send + 'tcx>;
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index 484e541afc58..4fb6d65a6e98 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -19,7 +19,6 @@ use rustc_target::spec::abi::Abi as SpecAbi;
 use std::cmp;
 use std::iter;
 use std::ops::ControlFlow;
-use tracing::debug;
 
 declare_lint! {
     /// The `unused_comparisons` lint detects comparisons made useless by
@@ -720,7 +719,7 @@ fn get_nullable_type<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'t
     Some(match *ty.kind() {
         ty::Adt(field_def, field_substs) => {
             let inner_field_ty = {
-                let first_non_zst_ty = field_def
+                let mut first_non_zst_ty = field_def
                     .variants()
                     .iter()
                     .filter_map(|v| transparent_newtype_field(cx.tcx, v));
@@ -730,7 +729,7 @@ fn get_nullable_type<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'t
                     "Wrong number of fields for transparent type"
                 );
                 first_non_zst_ty
-                    .last()
+                    .next_back()
                     .expect("No non-zst fields in transparent type.")
                     .ty(tcx, field_substs)
             };
@@ -1459,7 +1458,7 @@ impl InvalidAtomicOrdering {
             sym::AtomicI64,
             sym::AtomicI128,
         ];
-        if let ExprKind::MethodCall(ref method_path, args, _) = &expr.kind
+        if let ExprKind::MethodCall(ref method_path, _, args, _) = &expr.kind
             && recognized_names.contains(&method_path.ident.name)
             && let Some(m_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
             && let Some(impl_did) = cx.tcx.impl_of_method(m_def_id)
@@ -1495,8 +1494,8 @@ impl InvalidAtomicOrdering {
     fn check_atomic_load_store(cx: &LateContext<'_>, expr: &Expr<'_>) {
         if let Some((method, args)) = Self::inherent_atomic_method_call(cx, expr, &[sym::load, sym::store])
             && let Some((ordering_arg, invalid_ordering)) = match method {
-                sym::load => Some((&args[1], sym::Release)),
-                sym::store => Some((&args[2], sym::Acquire)),
+                sym::load => Some((&args[0], sym::Release)),
+                sym::store => Some((&args[1], sym::Acquire)),
                 _ => None,
             }
             && let Some(ordering) = Self::match_ordering(cx, ordering_arg)
@@ -1537,8 +1536,8 @@ impl InvalidAtomicOrdering {
             else {return };
 
         let fail_order_arg = match method {
-            sym::fetch_update => &args[2],
-            sym::compare_exchange | sym::compare_exchange_weak => &args[4],
+            sym::fetch_update => &args[1],
+            sym::compare_exchange | sym::compare_exchange_weak => &args[3],
             _ => return,
         };
 
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 58b2f0a44161..3d426ecbfcb0 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -222,7 +222,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                     }
                     has_emitted
                 }
-                ty::Dynamic(binder, _) => {
+                ty::Dynamic(binder, _, _) => {
                     let mut has_emitted = false;
                     for predicate in binder.iter() {
                         if let ty::ExistentialPredicate::Trait(ref trait_ref) =
@@ -268,7 +268,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 },
                 ty::Closure(..) => {
                     cx.struct_span_lint(UNUSED_MUST_USE, span, |lint| {
-                        // FIXME(davidtwco): this isn't properly translatable becauses of the
+                        // FIXME(davidtwco): this isn't properly translatable because of the
                         // pre/post strings
                         lint.build(fluent::lint::unused_closure)
                             .set_arg("count", plural_len)
@@ -281,7 +281,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 }
                 ty::Generator(..) => {
                     cx.struct_span_lint(UNUSED_MUST_USE, span, |lint| {
-                        // FIXME(davidtwco): this isn't properly translatable becauses of the
+                        // FIXME(davidtwco): this isn't properly translatable because of the
                         // pre/post strings
                         lint.build(fluent::lint::unused_generator)
                             .set_arg("count", plural_len)
@@ -310,7 +310,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
         ) -> bool {
             if let Some(attr) = cx.tcx.get_attr(def_id, sym::must_use) {
                 cx.struct_span_lint(UNUSED_MUST_USE, span, |lint| {
-                    // FIXME(davidtwco): this isn't properly translatable becauses of the pre/post
+                    // FIXME(davidtwco): this isn't properly translatable because of the pre/post
                     // strings
                     let mut err = lint.build(fluent::lint::unused_def);
                     err.set_arg("pre", descr_pre_path);
@@ -751,7 +751,7 @@ impl UnusedParens {
         avoid_or: bool,
         avoid_mut: bool,
     ) {
-        use ast::{BindingMode, Mutability, PatKind};
+        use ast::{BindingAnnotation, PatKind};
 
         if let PatKind::Paren(inner) = &value.kind {
             match inner.kind {
@@ -763,7 +763,9 @@ impl UnusedParens {
                 // Avoid `p0 | .. | pn` if we should.
                 PatKind::Or(..) if avoid_or => return,
                 // Avoid `mut x` and `mut x @ p` if we should:
-                PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ..) if avoid_mut => return,
+                PatKind::Ident(BindingAnnotation::MUT, ..) if avoid_mut => {
+                    return;
+                }
                 // Otherwise proceed with linting.
                 _ => {}
             }
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 2dca6acdd6d6..e5dfda24dc70 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -3206,7 +3206,7 @@ declare_lint! {
     /// [future-incompatible]: ../index.md#future-incompatible-lints
     pub REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS,
     Warn,
-    "tranparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields",
+    "transparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #78586 <https://github.com/rust-lang/rust/issues/78586>",
     };
@@ -3365,7 +3365,6 @@ declare_lint_pass! {
         DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
         DUPLICATE_MACRO_ATTRIBUTES,
         SUSPICIOUS_AUTO_TRAIT_IMPLS,
-        UNEXPECTED_CFGS,
         DEPRECATED_WHERE_CLAUSE_LOCATION,
         TEST_UNSTABLE_LINT,
         FFI_UNWIND_CALLS,
@@ -3408,7 +3407,7 @@ declare_lint! {
     ///
     /// ### Example of drop reorder
     ///
-    /// ```rust,compile_fail
+    /// ```rust,edition2018,compile_fail
     /// #![deny(rust_2021_incompatible_closure_captures)]
     /// # #![allow(unused)]
     ///
@@ -3444,7 +3443,7 @@ declare_lint! {
     ///
     /// ### Example of auto-trait
     ///
-    /// ```rust,compile_fail
+    /// ```rust,edition2018,compile_fail
     /// #![deny(rust_2021_incompatible_closure_captures)]
     /// use std::thread;
     ///
@@ -3989,8 +3988,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(generic_associated_types)]
-    ///
     /// trait Trait {
     ///   type Assoc<'a> where Self: 'a;
     /// }
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index 9c6530c8a084..11b2d057a076 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -658,18 +658,21 @@ macro_rules! declare_lint {
 macro_rules! declare_tool_lint {
     (
         $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level: ident, $desc: expr
+        $(, @feature_gate = $gate:expr;)?
     ) => (
-        $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, false}
+        $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, false $(, @feature_gate = $gate;)?}
     );
     (
         $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
         report_in_external_macro: $rep:expr
+        $(, @feature_gate = $gate:expr;)?
     ) => (
-         $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, $rep}
+         $crate::declare_tool_lint!{$(#[$attr])* $vis $tool::$NAME, $Level, $desc, $rep $(, @feature_gate = $gate;)?}
     );
     (
         $(#[$attr:meta])* $vis:vis $tool:ident ::$NAME:ident, $Level:ident, $desc:expr,
         $external:expr
+        $(, @feature_gate = $gate:expr;)?
     ) => (
         $(#[$attr])*
         $vis static $NAME: &$crate::Lint = &$crate::Lint {
@@ -680,8 +683,9 @@ macro_rules! declare_tool_lint {
             report_in_external_macro: $external,
             future_incompatible: None,
             is_plugin: true,
-            feature_gate: None,
+            $(feature_gate: Some($gate),)?
             crate_level_only: false,
+            ..$crate::Lint::default_fields_for_macro()
         };
     );
 }
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 05d2a214d0b7..09f377d349f4 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -31,13 +31,12 @@
 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include "llvm/Transforms/IPO/FunctionImport.h"
-#if LLVM_VERSION_GE(15, 0)
+#include "llvm/Transforms/IPO/Internalize.h"
 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
-#endif
 #include "llvm/Transforms/Utils/AddDiscriminators.h"
 #include "llvm/Transforms/Utils/FunctionImportUtils.h"
 #include "llvm/LTO/LTO.h"
-#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm-c/Transforms/PassManagerBuilder.h"
 
 #include "llvm/Transforms/Instrumentation.h"
@@ -93,167 +92,6 @@ extern "C" void LLVMTimeTraceProfilerFinish(const char* FileName) {
   timeTraceProfilerCleanup();
 }
 
-extern "C" LLVMPassRef LLVMRustFindAndCreatePass(const char *PassName) {
-#if LLVM_VERSION_LT(15, 0)
-  StringRef SR(PassName);
-  PassRegistry *PR = PassRegistry::getPassRegistry();
-
-  const PassInfo *PI = PR->getPassInfo(SR);
-  if (PI) {
-    return wrap(PI->createPass());
-  }
-  return nullptr;
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" LLVMPassRef LLVMRustCreateAddressSanitizerFunctionPass(bool Recover) {
-#if LLVM_VERSION_LT(15, 0)
-  const bool CompileKernel = false;
-  const bool UseAfterScope = true;
-
-  return wrap(createAddressSanitizerFunctionPass(CompileKernel, Recover, UseAfterScope));
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" LLVMPassRef LLVMRustCreateModuleAddressSanitizerPass(bool Recover) {
-#if LLVM_VERSION_LT(15, 0)
-  const bool CompileKernel = false;
-
-  return wrap(createModuleAddressSanitizerLegacyPassPass(CompileKernel, Recover));
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" LLVMPassRef LLVMRustCreateMemorySanitizerPass(int TrackOrigins, bool Recover) {
-#if LLVM_VERSION_LT(15, 0)
-  const bool CompileKernel = false;
-
-  return wrap(createMemorySanitizerLegacyPassPass(
-      MemorySanitizerOptions{TrackOrigins, Recover, CompileKernel}));
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" LLVMPassRef LLVMRustCreateThreadSanitizerPass() {
-#if LLVM_VERSION_LT(15, 0)
-  return wrap(createThreadSanitizerLegacyPassPass());
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" LLVMPassRef LLVMRustCreateHWAddressSanitizerPass(bool Recover) {
-#if LLVM_VERSION_LT(15, 0)
-  const bool CompileKernel = false;
-
-  return wrap(createHWAddressSanitizerLegacyPassPass(CompileKernel, Recover));
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" void LLVMRustAddPass(LLVMPassManagerRef PMR, LLVMPassRef RustPass) {
-#if LLVM_VERSION_LT(15, 0)
-  assert(RustPass);
-  Pass *Pass = unwrap(RustPass);
-  PassManagerBase *PMB = unwrap(PMR);
-  PMB->add(Pass);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" LLVMPassManagerBuilderRef LLVMRustPassManagerBuilderCreate() {
-#if LLVM_VERSION_LT(15, 0)
-  return LLVMPassManagerBuilderCreate();
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" void LLVMRustPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
-#if LLVM_VERSION_LT(15, 0)
-  LLVMPassManagerBuilderDispose(PMB);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" void LLVMRustPassManagerBuilderPopulateFunctionPassManager(
-  LLVMPassManagerBuilderRef PMB, LLVMPassManagerRef PM) {
-#if LLVM_VERSION_LT(15, 0)
-  LLVMPassManagerBuilderPopulateFunctionPassManager(PMB, PM);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" void LLVMRustPassManagerBuilderPopulateModulePassManager(
-  LLVMPassManagerBuilderRef PMB, LLVMPassManagerRef PM) {
-#if LLVM_VERSION_LT(15, 0)
-  LLVMPassManagerBuilderPopulateModulePassManager(PMB, PM);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" void LLVMRustPassManagerBuilderPopulateLTOPassManager(
-  LLVMPassManagerBuilderRef PMB, LLVMPassManagerRef PM, bool Internalize, bool RunInliner) {
-#if LLVM_VERSION_LT(15, 0)
-  LLVMPassManagerBuilderPopulateLTOPassManager(PMB, PM, Internalize, RunInliner);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C"
-void LLVMRustPassManagerBuilderPopulateThinLTOPassManager(
-  LLVMPassManagerBuilderRef PMBR,
-  LLVMPassManagerRef PMR
-) {
-#if LLVM_VERSION_LT(15, 0)
-  unwrap(PMBR)->populateThinLTOPassManager(*unwrap(PMR));
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C" void LLVMRustPassManagerBuilderUseInlinerWithThreshold(
-  LLVMPassManagerBuilderRef PMB, unsigned Threshold) {
-#if LLVM_VERSION_LT(15, 0)
-  LLVMPassManagerBuilderUseInlinerWithThreshold(PMB, Threshold);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-extern "C"
-void LLVMRustAddLastExtensionPasses(
-    LLVMPassManagerBuilderRef PMBR, LLVMPassRef *Passes, size_t NumPasses) {
-#if LLVM_VERSION_LT(15, 0)
-  auto AddExtensionPasses = [Passes, NumPasses](
-      const PassManagerBuilder &Builder, PassManagerBase &PM) {
-    for (size_t I = 0; I < NumPasses; I++) {
-      PM.add(unwrap(Passes[I]));
-    }
-  };
-  // Add the passes to both of the pre-finalization extension points,
-  // so they are run for optimized and non-optimized builds.
-  unwrap(PMBR)->addExtension(PassManagerBuilder::EP_OptimizerLast,
-                             AddExtensionPasses);
-  unwrap(PMBR)->addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
-                             AddExtensionPasses);
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
 #ifdef LLVM_COMPONENT_X86
 #define SUBTARGET_X86 SUBTARGET(X86)
 #else
@@ -599,47 +437,6 @@ extern "C" void LLVMRustDisposeTargetMachine(LLVMTargetMachineRef TM) {
   delete unwrap(TM);
 }
 
-extern "C" void LLVMRustConfigurePassManagerBuilder(
-    LLVMPassManagerBuilderRef PMBR, LLVMRustCodeGenOptLevel OptLevel,
-    bool MergeFunctions, bool SLPVectorize, bool LoopVectorize, bool PrepareForThinLTO,
-    const char* PGOGenPath, const char* PGOUsePath, const char* PGOSampleUsePath,
-    int SizeLevel) {
-#if LLVM_VERSION_LT(15, 0)
-  unwrap(PMBR)->MergeFunctions = MergeFunctions;
-  unwrap(PMBR)->SLPVectorize = SLPVectorize;
-  unwrap(PMBR)->OptLevel = fromRust(OptLevel);
-  unwrap(PMBR)->LoopVectorize = LoopVectorize;
-  unwrap(PMBR)->PrepareForThinLTO = PrepareForThinLTO;
-  unwrap(PMBR)->SizeLevel = SizeLevel;
-  unwrap(PMBR)->DisableUnrollLoops = SizeLevel != 0;
-
-  if (PGOGenPath) {
-    assert(!PGOUsePath && !PGOSampleUsePath);
-    unwrap(PMBR)->EnablePGOInstrGen = true;
-    unwrap(PMBR)->PGOInstrGen = PGOGenPath;
-  } else if (PGOUsePath) {
-    assert(!PGOSampleUsePath);
-    unwrap(PMBR)->PGOInstrUse = PGOUsePath;
-  } else if (PGOSampleUsePath) {
-    unwrap(PMBR)->PGOSampleUse = PGOSampleUsePath;
-  }
-#else
-  report_fatal_error("Legacy PM not supported with LLVM 15");
-#endif
-}
-
-// Unfortunately, the LLVM C API doesn't provide a way to set the `LibraryInfo`
-// field of a PassManagerBuilder, we expose our own method of doing so.
-extern "C" void LLVMRustAddBuilderLibraryInfo(LLVMPassManagerBuilderRef PMBR,
-                                              LLVMModuleRef M,
-                                              bool DisableSimplifyLibCalls) {
-  Triple TargetTriple(unwrap(M)->getTargetTriple());
-  TargetLibraryInfoImpl *TLI = new TargetLibraryInfoImpl(TargetTriple);
-  if (DisableSimplifyLibCalls)
-    TLI->disableAllFunctions();
-  unwrap(PMBR)->LibraryInfo = TLI;
-}
-
 // Unfortunately, the LLVM C API doesn't provide a way to create the
 // TargetLibraryInfo pass, so we use this method to do so.
 extern "C" void LLVMRustAddLibraryInfo(LLVMPassManagerRef PMR, LLVMModuleRef M,
@@ -651,27 +448,6 @@ extern "C" void LLVMRustAddLibraryInfo(LLVMPassManagerRef PMR, LLVMModuleRef M,
   unwrap(PMR)->add(new TargetLibraryInfoWrapperPass(TLII));
 }
 
-// Unfortunately, the LLVM C API doesn't provide an easy way of iterating over
-// all the functions in a module, so we do that manually here. You'll find
-// similar code in clang's BackendUtil.cpp file.
-extern "C" void LLVMRustRunFunctionPassManager(LLVMPassManagerRef PMR,
-                                               LLVMModuleRef M) {
-  llvm::legacy::FunctionPassManager *P =
-      unwrap<llvm::legacy::FunctionPassManager>(PMR);
-  P->doInitialization();
-
-  // Upgrade all calls to old intrinsics first.
-  for (Module::iterator I = unwrap(M)->begin(), E = unwrap(M)->end(); I != E;)
-    UpgradeCallsToIntrinsic(&*I++); // must be post-increment, as we remove
-
-  for (Module::iterator I = unwrap(M)->begin(), E = unwrap(M)->end(); I != E;
-       ++I)
-    if (!I->isDeclaration())
-      P->run(*I);
-
-  P->doFinalization();
-}
-
 extern "C" void LLVMRustSetLLVMOptions(int Argc, char **Argv) {
   // Initializing the command-line options more than once is not allowed. So,
   // check if they've already been initialized.  (This could happen if we're
@@ -815,7 +591,7 @@ struct LLVMRustSanitizerOptions {
 };
 
 extern "C" LLVMRustResult
-LLVMRustOptimizeWithNewPassManager(
+LLVMRustOptimize(
     LLVMModuleRef ModuleRef,
     LLVMTargetMachineRef TMRef,
     LLVMRustPassBuilderOptLevel OptLevelRust,
@@ -930,18 +706,28 @@ LLVMRustOptimizeWithNewPassManager(
 
   if (SanitizerOptions) {
     if (SanitizerOptions->SanitizeMemory) {
+#if LLVM_VERSION_GE(14, 0)
+      MemorySanitizerOptions Options(
+          SanitizerOptions->SanitizeMemoryTrackOrigins,
+          SanitizerOptions->SanitizeMemoryRecover,
+          /*CompileKernel=*/false,
+          /*EagerChecks=*/true);
+#else
       MemorySanitizerOptions Options(
           SanitizerOptions->SanitizeMemoryTrackOrigins,
           SanitizerOptions->SanitizeMemoryRecover,
           /*CompileKernel=*/false);
+#endif
       OptimizerLastEPCallbacks.push_back(
         [Options](ModulePassManager &MPM, OptimizationLevel Level) {
-#if LLVM_VERSION_GE(14, 0)
+#if LLVM_VERSION_GE(14, 0) && LLVM_VERSION_LT(16, 0)
           MPM.addPass(ModuleMemorySanitizerPass(Options));
 #else
           MPM.addPass(MemorySanitizerPass(Options));
 #endif
+#if LLVM_VERSION_LT(16, 0)
           MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass(Options)));
+#endif
         }
       );
     }
@@ -972,7 +758,11 @@ LLVMRustOptimizeWithNewPassManager(
             /*UseAfterScope=*/true,
             AsanDetectStackUseAfterReturnMode::Runtime,
           };
+#if LLVM_VERSION_LT(16, 0)
           MPM.addPass(ModuleAddressSanitizerPass(opts));
+#else
+          MPM.addPass(AddressSanitizerPass(opts));
+#endif
 #else
           MPM.addPass(ModuleAddressSanitizerPass(
               /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover));
@@ -1222,15 +1012,8 @@ extern "C" void LLVMRustPrintPasses() {
   PR->enumerateWith(&Listener);
 }
 
-extern "C" void LLVMRustAddAlwaysInlinePass(LLVMPassManagerBuilderRef PMBR,
-                                            bool AddLifetimes) {
-  unwrap(PMBR)->Inliner = llvm::createAlwaysInlinerLegacyPass(AddLifetimes);
-}
-
 extern "C" void LLVMRustRunRestrictionPass(LLVMModuleRef M, char **Symbols,
                                            size_t Len) {
-  llvm::legacy::PassManager passes;
-
   auto PreserveFunctions = [=](const GlobalValue &GV) {
     for (size_t I = 0; I < Len; I++) {
       if (GV.getName() == Symbols[I]) {
@@ -1240,9 +1023,7 @@ extern "C" void LLVMRustRunRestrictionPass(LLVMModuleRef M, char **Symbols,
     return false;
   };
 
-  passes.add(llvm::createInternalizePass(PreserveFunctions));
-
-  passes.run(*unwrap(M));
+  internalizeModule(*unwrap(M), PreserveFunctions);
 }
 
 extern "C" void
@@ -1591,11 +1372,6 @@ LLVMRustThinLTOBufferCreate(LLVMModuleRef M, bool is_thin) {
     raw_string_ostream OS(Ret->data);
     {
       if (is_thin) {
-#if LLVM_VERSION_LT(15, 0)
-        legacy::PassManager PM;
-        PM.add(createWriteThinLTOBitcodePass(OS));
-        PM.run(*unwrap(M));
-#else
         PassBuilder PB;
         LoopAnalysisManager LAM;
         FunctionAnalysisManager FAM;
@@ -1609,11 +1385,8 @@ LLVMRustThinLTOBufferCreate(LLVMModuleRef M, bool is_thin) {
         ModulePassManager MPM;
         MPM.addPass(ThinLTOBitcodeWriterPass(OS, nullptr));
         MPM.run(*unwrap(M), MAM);
-#endif
       } else {
-        legacy::PassManager PM;
-        PM.add(createBitcodeWriterPass(OS));
-        PM.run(*unwrap(M));
+        WriteBitcodeToFile(*unwrap(M), OS);
       }
     }
   }
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 931ce78721cb..6f36281af23c 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -12,7 +12,7 @@
 #include "llvm/Object/COFFImportFile.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Pass.h"
-#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/ADT/Optional.h"
 
@@ -406,45 +406,6 @@ extern "C" LLVMValueRef LLVMRustBuildAtomicStore(LLVMBuilderRef B,
   return wrap(SI);
 }
 
-// FIXME: Use the C-API LLVMBuildAtomicCmpXchg and LLVMSetWeak
-// once we raise our minimum support to LLVM 10.
-extern "C" LLVMValueRef
-LLVMRustBuildAtomicCmpXchg(LLVMBuilderRef B, LLVMValueRef Target,
-                           LLVMValueRef Old, LLVMValueRef Source,
-                           LLVMAtomicOrdering Order,
-                           LLVMAtomicOrdering FailureOrder, LLVMBool Weak) {
-  // Rust probably knows the alignment of the target value and should be able to
-  // specify something more precise than MaybeAlign here. See also
-  // https://reviews.llvm.org/D97224 which may be a useful reference.
-  AtomicCmpXchgInst *ACXI = unwrap(B)->CreateAtomicCmpXchg(
-      unwrap(Target), unwrap(Old), unwrap(Source), llvm::MaybeAlign(), fromRust(Order),
-      fromRust(FailureOrder));
-  ACXI->setWeak(Weak);
-  return wrap(ACXI);
-}
-
-enum class LLVMRustSynchronizationScope {
-  SingleThread,
-  CrossThread,
-};
-
-static SyncScope::ID fromRust(LLVMRustSynchronizationScope Scope) {
-  switch (Scope) {
-  case LLVMRustSynchronizationScope::SingleThread:
-    return SyncScope::SingleThread;
-  case LLVMRustSynchronizationScope::CrossThread:
-    return SyncScope::System;
-  default:
-    report_fatal_error("bad SynchronizationScope.");
-  }
-}
-
-extern "C" LLVMValueRef
-LLVMRustBuildAtomicFence(LLVMBuilderRef B, LLVMAtomicOrdering Order,
-                         LLVMRustSynchronizationScope Scope) {
-  return wrap(unwrap(B)->CreateFence(fromRust(Order), fromRust(Scope)));
-}
-
 enum class LLVMRustAsmDialect {
   Att,
   Intel,
@@ -1618,6 +1579,14 @@ extern "C" LLVMValueRef LLVMRustConstInBoundsGEP2(LLVMTypeRef Ty,
   return wrap(ConstantExpr::getInBoundsGetElementPtr(unwrap(Ty), Val, IdxList));
 }
 
+extern "C" bool LLVMRustConstIntGetZExtValue(LLVMValueRef CV, uint64_t *value) {
+    auto C = unwrap<llvm::ConstantInt>(CV);
+    if (C->getBitWidth() > 64)
+      return false;
+    *value = C->getZExtValue();
+    return true;
+}
+
 // Returns true if both high and low were successfully set. Fails in case constant wasn’t any of
 // the common sizes (1, 8, 16, 32, 64, 128 bits)
 extern "C" bool LLVMRustConstInt128Get(LLVMValueRef CV, bool sext, uint64_t *high, uint64_t *low)
@@ -1701,11 +1670,7 @@ LLVMRustModuleBufferCreate(LLVMModuleRef M) {
   auto Ret = std::make_unique<LLVMRustModuleBuffer>();
   {
     raw_string_ostream OS(Ret->data);
-    {
-      legacy::PassManager PM;
-      PM.add(createBitcodeWriterPass(OS));
-      PM.run(*unwrap(M));
-    }
+    WriteBitcodeToFile(*unwrap(M), OS);
   }
   return Ret.release();
 }
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic.rs b/compiler/rustc_macros/src/diagnostics/diagnostic.rs
index 244edec28415..3b8d9594eb91 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic.rs
@@ -9,29 +9,29 @@ use syn::spanned::Spanned;
 use synstructure::Structure;
 
 /// The central struct for constructing the `into_diagnostic` method from an annotated struct.
-pub(crate) struct SessionDiagnosticDerive<'a> {
+pub(crate) struct DiagnosticDerive<'a> {
     structure: Structure<'a>,
-    sess: syn::Ident,
+    handler: syn::Ident,
     builder: DiagnosticDeriveBuilder,
 }
 
-impl<'a> SessionDiagnosticDerive<'a> {
-    pub(crate) fn new(diag: syn::Ident, sess: syn::Ident, structure: Structure<'a>) -> Self {
+impl<'a> DiagnosticDerive<'a> {
+    pub(crate) fn new(diag: syn::Ident, handler: syn::Ident, structure: Structure<'a>) -> Self {
         Self {
             builder: DiagnosticDeriveBuilder {
                 diag,
                 fields: build_field_mapping(&structure),
-                kind: DiagnosticDeriveKind::SessionDiagnostic,
+                kind: DiagnosticDeriveKind::Diagnostic,
                 code: None,
                 slug: None,
             },
-            sess,
+            handler,
             structure,
         }
     }
 
     pub(crate) fn into_tokens(self) -> TokenStream {
-        let SessionDiagnosticDerive { mut structure, sess, mut builder } = self;
+        let DiagnosticDerive { mut structure, handler, mut builder } = self;
 
         let ast = structure.ast();
         let implementation = {
@@ -53,7 +53,7 @@ impl<'a> SessionDiagnosticDerive<'a> {
                     }
                     Some(slug) => {
                         quote! {
-                            let mut #diag = #sess.struct_diagnostic(rustc_errors::fluent::#slug);
+                            let mut #diag = #handler.struct_diagnostic(rustc_errors::fluent::#slug);
                         }
                     }
                 };
@@ -72,7 +72,7 @@ impl<'a> SessionDiagnosticDerive<'a> {
             } else {
                 span_err(
                     ast.span().unwrap(),
-                    "`#[derive(SessionDiagnostic)]` can only be used on structs",
+                    "`#[derive(Diagnostic)]` can only be used on structs",
                 )
                 .emit();
 
@@ -81,15 +81,15 @@ impl<'a> SessionDiagnosticDerive<'a> {
         };
 
         structure.gen_impl(quote! {
-            gen impl<'__session_diagnostic_sess, G>
-                    rustc_session::SessionDiagnostic<'__session_diagnostic_sess, G>
+            gen impl<'__diagnostic_handler_sess, G>
+                    rustc_errors::IntoDiagnostic<'__diagnostic_handler_sess, G>
                     for @Self
                 where G: rustc_errors::EmissionGuarantee
             {
                 fn into_diagnostic(
                     self,
-                    #sess: &'__session_diagnostic_sess rustc_session::parse::ParseSess
-                ) -> rustc_errors::DiagnosticBuilder<'__session_diagnostic_sess, G> {
+                    #handler: &'__diagnostic_handler_sess rustc_errors::Handler
+                ) -> rustc_errors::DiagnosticBuilder<'__diagnostic_handler_sess, G> {
                     use rustc_errors::IntoDiagnosticArg;
                     #implementation
                 }
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
index a4ccfcace192..2aa292bbce2b 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
@@ -1,17 +1,17 @@
 #![deny(unused_must_use)]
 
+use super::error::throw_invalid_nested_attr;
+use super::utils::{SpannedOption, SubdiagnosticKind};
 use crate::diagnostics::error::{
-    invalid_nested_attr, span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err,
-    DiagnosticDeriveError,
+    invalid_nested_attr, span_err, throw_invalid_attr, throw_span_err, DiagnosticDeriveError,
 };
 use crate::diagnostics::utils::{
     report_error_if_not_applied_to_span, report_type_error, type_is_unit, type_matches_path,
-    Applicability, FieldInfo, FieldInnerTy, HasFieldMap, SetOnce,
+    FieldInfo, FieldInnerTy, HasFieldMap, SetOnce,
 };
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::{format_ident, quote};
 use std::collections::HashMap;
-use std::str::FromStr;
 use syn::{
     parse_quote, spanned::Spanned, Attribute, Field, Meta, MetaList, MetaNameValue, NestedMeta,
     Path, Type,
@@ -21,12 +21,12 @@ use synstructure::{BindingInfo, Structure};
 /// What kind of diagnostic is being derived - a fatal/error/warning or a lint?
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub(crate) enum DiagnosticDeriveKind {
-    SessionDiagnostic,
+    Diagnostic,
     LintDiagnostic,
 }
 
 /// Tracks persistent information required for building up individual calls to diagnostic methods
-/// for generated diagnostic derives - both `SessionDiagnostic` for fatal/errors/warnings and
+/// for generated diagnostic derives - both `Diagnostic` for fatal/errors/warnings and
 /// `LintDiagnostic` for lints.
 pub(crate) struct DiagnosticDeriveBuilder {
     /// The identifier to use for the generated `DiagnosticBuilder` instance.
@@ -40,10 +40,10 @@ pub(crate) struct DiagnosticDeriveBuilder {
     pub kind: DiagnosticDeriveKind,
     /// Slug is a mandatory part of the struct attribute as corresponds to the Fluent message that
     /// has the actual diagnostic message.
-    pub slug: Option<(Path, proc_macro::Span)>,
+    pub slug: SpannedOption<Path>,
     /// Error codes are a optional part of the struct attribute - this is only set to detect
     /// multiple specifications.
-    pub code: Option<(String, proc_macro::Span)>,
+    pub code: SpannedOption<()>,
 }
 
 impl HasFieldMap for DiagnosticDeriveBuilder {
@@ -127,6 +127,30 @@ impl DiagnosticDeriveBuilder {
             || is_subdiagnostic
     }
 
+    fn parse_subdiag_attribute(
+        &self,
+        attr: &Attribute,
+    ) -> Result<(SubdiagnosticKind, Path), DiagnosticDeriveError> {
+        let (subdiag, slug) = SubdiagnosticKind::from_attr(attr, self)?;
+
+        if let SubdiagnosticKind::MultipartSuggestion { .. } = subdiag {
+            let meta = attr.parse_meta()?;
+            throw_invalid_attr!(attr, &meta, |diag| diag
+                .help("consider creating a `Subdiagnostic` instead"));
+        }
+
+        let slug = slug.unwrap_or_else(|| match subdiag {
+            SubdiagnosticKind::Label => parse_quote! { _subdiag::label },
+            SubdiagnosticKind::Note => parse_quote! { _subdiag::note },
+            SubdiagnosticKind::Help => parse_quote! { _subdiag::help },
+            SubdiagnosticKind::Warn => parse_quote! { _subdiag::warn },
+            SubdiagnosticKind::Suggestion { .. } => parse_quote! { _subdiag::suggestion },
+            SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(),
+        });
+
+        Ok((subdiag, slug))
+    }
+
     /// Establishes state in the `DiagnosticDeriveBuilder` resulting from the struct
     /// attributes like `#[diag(..)]`, such as the slug and error code. Generates
     /// diagnostic builder calls for setting error code and creating note/help messages.
@@ -135,98 +159,64 @@ impl DiagnosticDeriveBuilder {
         attr: &Attribute,
     ) -> Result<TokenStream, DiagnosticDeriveError> {
         let diag = &self.diag;
-        let span = attr.span().unwrap();
 
         let name = attr.path.segments.last().unwrap().ident.to_string();
         let name = name.as_str();
         let meta = attr.parse_meta()?;
 
-        let is_diag = name == "diag";
+        if name == "diag" {
+            let Meta::List(MetaList { ref nested, .. }) = meta else {
+                throw_invalid_attr!(
+                    attr,
+                    &meta
+                );
+            };
 
-        let nested = match meta {
-            // Most attributes are lists, like `#[diag(..)]` for most cases or
-            // `#[help(..)]`/`#[note(..)]` when the user is specifying a alternative slug.
-            Meta::List(MetaList { ref nested, .. }) => nested,
-            // Subdiagnostics without spans can be applied to the type too, and these are just
-            // paths: `#[help]`, `#[note]` and `#[warning]`
-            Meta::Path(_) if !is_diag => {
-                let fn_name = if name == "warning" {
-                    Ident::new("warn", attr.span())
-                } else {
-                    Ident::new(name, attr.span())
-                };
-                return Ok(quote! { #diag.#fn_name(rustc_errors::fluent::_subdiag::#fn_name); });
-            }
-            _ => throw_invalid_attr!(attr, &meta),
-        };
+            let mut nested_iter = nested.into_iter().peekable();
 
-        // Check the kind before doing any further processing so that there aren't misleading
-        // "no kind specified" errors if there are failures later.
-        match name {
-            "error" | "lint" => throw_invalid_attr!(attr, &meta, |diag| {
-                diag.help("`error` and `lint` have been replaced by `diag`")
-            }),
-            "warn_" => throw_invalid_attr!(attr, &meta, |diag| {
-                diag.help("`warn_` have been replaced by `warning`")
-            }),
-            "diag" | "help" | "note" | "warning" => (),
-            _ => throw_invalid_attr!(attr, &meta, |diag| {
-                diag.help("only `diag`, `help`, `note` and `warning` are valid attributes")
-            }),
-        }
+            match nested_iter.peek() {
+                Some(NestedMeta::Meta(Meta::Path(slug))) => {
+                    self.slug.set_once(slug.clone(), slug.span().unwrap());
+                    nested_iter.next();
+                }
+                Some(NestedMeta::Meta(Meta::NameValue { .. })) => {}
+                Some(nested_attr) => throw_invalid_nested_attr!(attr, &nested_attr, |diag| diag
+                    .help("a diagnostic slug is required as the first argument")),
+                None => throw_invalid_attr!(attr, &meta, |diag| diag
+                    .help("a diagnostic slug is required as the first argument")),
+            };
 
-        // First nested element should always be the path, e.g. `#[diag(typeck::invalid)]` or
-        // `#[help(typeck::another_help)]`.
-        let mut nested_iter = nested.into_iter();
-        if let Some(nested_attr) = nested_iter.next() {
-            // Report an error if there are any other list items after the path.
-            if !is_diag && nested_iter.next().is_some() {
-                throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                    diag.help(
-                        "`help`, `note` and `warning` struct attributes can only have one argument",
-                    )
-                });
-            }
-
-            match nested_attr {
-                NestedMeta::Meta(Meta::Path(path)) => {
-                    if is_diag {
-                        self.slug.set_once((path.clone(), span));
-                    } else {
-                        let fn_name = proc_macro2::Ident::new(name, attr.span());
-                        return Ok(quote! { #diag.#fn_name(rustc_errors::fluent::#path); });
+            // Remaining attributes are optional, only `code = ".."` at the moment.
+            let mut tokens = TokenStream::new();
+            for nested_attr in nested_iter {
+                let (value, path) = match nested_attr {
+                    NestedMeta::Meta(Meta::NameValue(MetaNameValue {
+                        lit: syn::Lit::Str(value),
+                        path,
+                        ..
+                    })) => (value, path),
+                    NestedMeta::Meta(Meta::Path(_)) => {
+                        invalid_nested_attr(attr, &nested_attr)
+                            .help("diagnostic slug must be the first argument")
+                            .emit();
+                        continue;
                     }
-                }
-                NestedMeta::Meta(meta @ Meta::NameValue(_))
-                    if is_diag && meta.path().segments.last().unwrap().ident == "code" =>
-                {
-                    // don't error for valid follow-up attributes
-                }
-                nested_attr => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                    diag.help("first argument of the attribute should be the diagnostic slug")
-                }),
-            };
-        }
+                    _ => {
+                        invalid_nested_attr(attr, &nested_attr).emit();
+                        continue;
+                    }
+                };
 
-        // Remaining attributes are optional, only `code = ".."` at the moment.
-        let mut tokens = Vec::new();
-        for nested_attr in nested_iter {
-            let meta = match nested_attr {
-                syn::NestedMeta::Meta(meta) => meta,
-                _ => throw_invalid_nested_attr!(attr, &nested_attr),
-            };
-
-            let path = meta.path();
-            let nested_name = path.segments.last().unwrap().ident.to_string();
-            // Struct attributes are only allowed to be applied once, and the diagnostic
-            // changes will be set in the initialisation code.
-            if let Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) = &meta {
-                let span = s.span().unwrap();
+                let nested_name = path.segments.last().unwrap().ident.to_string();
+                // Struct attributes are only allowed to be applied once, and the diagnostic
+                // changes will be set in the initialisation code.
+                let span = value.span().unwrap();
                 match nested_name.as_str() {
                     "code" => {
-                        self.code.set_once((s.value(), span));
-                        let code = &self.code.as_ref().map(|(v, _)| v);
-                        tokens.push(quote! {
+                        self.code.set_once((), span);
+
+                        let code = value.value();
+                        tokens.extend(quote! {
                             #diag.code(rustc_errors::DiagnosticId::Error(#code.to_string()));
                         });
                     }
@@ -234,12 +224,22 @@ impl DiagnosticDeriveBuilder {
                         .help("only `code` is a valid nested attributes following the slug")
                         .emit(),
                 }
-            } else {
-                invalid_nested_attr(attr, &nested_attr).emit()
             }
+            return Ok(tokens);
         }
 
-        Ok(tokens.drain(..).collect())
+        let (subdiag, slug) = self.parse_subdiag_attribute(attr)?;
+        let fn_ident = format_ident!("{}", subdiag);
+        match subdiag {
+            SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => {
+                Ok(self.add_subdiagnostic(&fn_ident, slug))
+            }
+            SubdiagnosticKind::Label | SubdiagnosticKind::Suggestion { .. } => {
+                throw_invalid_attr!(attr, &meta, |diag| diag
+                    .help("`#[label]` and `#[suggestion]` can only be applied to fields"));
+            }
+            SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(),
+        }
     }
 
     fn generate_field_attrs_code(&mut self, binding_info: &BindingInfo<'_>) -> TokenStream {
@@ -303,232 +303,83 @@ impl DiagnosticDeriveBuilder {
         info: FieldInfo<'_>,
         binding: TokenStream,
     ) -> Result<TokenStream, DiagnosticDeriveError> {
-        let meta = attr.parse_meta()?;
-        match meta {
-            Meta::Path(_) => self.generate_inner_field_code_path(attr, info, binding),
-            Meta::List(MetaList { .. }) => self.generate_inner_field_code_list(attr, info, binding),
-            _ => throw_invalid_attr!(attr, &meta),
-        }
-    }
-
-    fn generate_inner_field_code_path(
-        &mut self,
-        attr: &Attribute,
-        info: FieldInfo<'_>,
-        binding: TokenStream,
-    ) -> Result<TokenStream, DiagnosticDeriveError> {
-        assert!(matches!(attr.parse_meta()?, Meta::Path(_)));
         let diag = &self.diag;
-
         let meta = attr.parse_meta()?;
 
-        let ident = &attr.path.segments.last().unwrap().ident;
-        let name = ident.to_string();
-        let name = name.as_str();
-        match name {
-            "skip_arg" => {
-                // Don't need to do anything - by virtue of the attribute existing, the
-                // `set_arg` call will not be generated.
-                Ok(quote! {})
-            }
-            "primary_span" => {
-                match self.kind {
-                    DiagnosticDeriveKind::SessionDiagnostic => {
+        if let Meta::Path(_) = meta {
+            let ident = &attr.path.segments.last().unwrap().ident;
+            let name = ident.to_string();
+            let name = name.as_str();
+            match name {
+                "skip_arg" => {
+                    // Don't need to do anything - by virtue of the attribute existing, the
+                    // `set_arg` call will not be generated.
+                    return Ok(quote! {});
+                }
+                "primary_span" => match self.kind {
+                    DiagnosticDeriveKind::Diagnostic => {
                         report_error_if_not_applied_to_span(attr, &info)?;
 
-                        Ok(quote! {
+                        return Ok(quote! {
                             #diag.set_span(#binding);
-                        })
+                        });
                     }
                     DiagnosticDeriveKind::LintDiagnostic => {
                         throw_invalid_attr!(attr, &meta, |diag| {
                             diag.help("the `primary_span` field attribute is not valid for lint diagnostics")
                         })
                     }
-                }
+                },
+                "subdiagnostic" => return Ok(quote! { #diag.subdiagnostic(#binding); }),
+                _ => {}
             }
-            "label" => {
+        }
+
+        let (subdiag, slug) = self.parse_subdiag_attribute(attr)?;
+
+        let fn_ident = format_ident!("{}", subdiag);
+        match subdiag {
+            SubdiagnosticKind::Label => {
                 report_error_if_not_applied_to_span(attr, &info)?;
-                Ok(self.add_spanned_subdiagnostic(binding, ident, parse_quote! { _subdiag::label }))
+                Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug))
             }
-            "note" | "help" | "warning" => {
-                let warn_ident = Ident::new("warn", Span::call_site());
-                let (ident, path) = match name {
-                    "note" => (ident, parse_quote! { _subdiag::note }),
-                    "help" => (ident, parse_quote! { _subdiag::help }),
-                    "warning" => (&warn_ident, parse_quote! { _subdiag::warn }),
-                    _ => unreachable!(),
-                };
+            SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => {
                 if type_matches_path(&info.ty, &["rustc_span", "Span"]) {
-                    Ok(self.add_spanned_subdiagnostic(binding, ident, path))
+                    Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug))
                 } else if type_is_unit(&info.ty) {
-                    Ok(self.add_subdiagnostic(ident, path))
+                    Ok(self.add_subdiagnostic(&fn_ident, slug))
                 } else {
                     report_type_error(attr, "`Span` or `()`")?
                 }
             }
-            "subdiagnostic" => Ok(quote! { #diag.subdiagnostic(#binding); }),
-            _ => throw_invalid_attr!(attr, &meta, |diag| {
-                diag.help(
-                    "only `skip_arg`, `primary_span`, `label`, `note`, `help` and `subdiagnostic` \
-                     are valid field attributes",
-                )
-            }),
-        }
-    }
+            SubdiagnosticKind::Suggestion {
+                suggestion_kind,
+                applicability: static_applicability,
+                code,
+            } => {
+                let (span_field, mut applicability) = self.span_and_applicability_of_ty(info)?;
 
-    fn generate_inner_field_code_list(
-        &mut self,
-        attr: &Attribute,
-        info: FieldInfo<'_>,
-        binding: TokenStream,
-    ) -> Result<TokenStream, DiagnosticDeriveError> {
-        let meta = attr.parse_meta()?;
-        let Meta::List(MetaList { ref path, ref nested, .. }) = meta  else { unreachable!() };
-
-        let ident = &attr.path.segments.last().unwrap().ident;
-        let name = path.segments.last().unwrap().ident.to_string();
-        let name = name.as_ref();
-        match name {
-            "suggestion" | "suggestion_short" | "suggestion_hidden" | "suggestion_verbose" => {
-                return self.generate_inner_field_code_suggestion(attr, info);
-            }
-            "label" | "help" | "note" | "warning" => (),
-            _ => throw_invalid_attr!(attr, &meta, |diag| {
-                diag.help(
-                    "only `label`, `help`, `note`, `warn` or `suggestion{,_short,_hidden,_verbose}` are \
-                     valid field attributes",
-                )
-            }),
-        }
-
-        // For `#[label(..)]`, `#[note(..)]` and `#[help(..)]`, the first nested element must be a
-        // path, e.g. `#[label(typeck::label)]`.
-        let mut nested_iter = nested.into_iter();
-        let msg = match nested_iter.next() {
-            Some(NestedMeta::Meta(Meta::Path(path))) => path.clone(),
-            Some(nested_attr) => throw_invalid_nested_attr!(attr, &nested_attr),
-            None => throw_invalid_attr!(attr, &meta),
-        };
-
-        // None of these attributes should have anything following the slug.
-        if nested_iter.next().is_some() {
-            throw_invalid_attr!(attr, &meta);
-        }
-
-        match name {
-            "label" => {
-                report_error_if_not_applied_to_span(attr, &info)?;
-                Ok(self.add_spanned_subdiagnostic(binding, ident, msg))
-            }
-            "note" | "help" if type_matches_path(&info.ty, &["rustc_span", "Span"]) => {
-                Ok(self.add_spanned_subdiagnostic(binding, ident, msg))
-            }
-            "note" | "help" if type_is_unit(&info.ty) => Ok(self.add_subdiagnostic(ident, msg)),
-            // `warning` must be special-cased because the attribute `warn` already has meaning and
-            // so isn't used, despite the diagnostic API being named `warn`.
-            "warning" if type_matches_path(&info.ty, &["rustc_span", "Span"]) => Ok(self
-                .add_spanned_subdiagnostic(binding, &Ident::new("warn", Span::call_site()), msg)),
-            "warning" if type_is_unit(&info.ty) => {
-                Ok(self.add_subdiagnostic(&Ident::new("warn", Span::call_site()), msg))
-            }
-            "note" | "help" | "warning" => report_type_error(attr, "`Span` or `()`")?,
-            _ => unreachable!(),
-        }
-    }
-
-    fn generate_inner_field_code_suggestion(
-        &mut self,
-        attr: &Attribute,
-        info: FieldInfo<'_>,
-    ) -> Result<TokenStream, DiagnosticDeriveError> {
-        let diag = &self.diag;
-
-        let mut meta = attr.parse_meta()?;
-        let Meta::List(MetaList { ref path, ref mut nested, .. }) = meta  else { unreachable!() };
-
-        let (span_field, mut applicability) = self.span_and_applicability_of_ty(info)?;
-
-        let mut msg = None;
-        let mut code = None;
-
-        let mut nested_iter = nested.into_iter().peekable();
-        if let Some(nested_attr) = nested_iter.peek() {
-            if let NestedMeta::Meta(Meta::Path(path)) = nested_attr {
-                msg = Some(path.clone());
-            }
-        };
-        // Move the iterator forward if a path was found (don't otherwise so that
-        // code/applicability can be found or an error emitted).
-        if msg.is_some() {
-            let _ = nested_iter.next();
-        }
-
-        for nested_attr in nested_iter {
-            let meta = match nested_attr {
-                syn::NestedMeta::Meta(ref meta) => meta,
-                syn::NestedMeta::Lit(_) => throw_invalid_nested_attr!(attr, &nested_attr),
-            };
-
-            let nested_name = meta.path().segments.last().unwrap().ident.to_string();
-            let nested_name = nested_name.as_str();
-            match meta {
-                Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) => {
-                    let span = meta.span().unwrap();
-                    match nested_name {
-                        "code" => {
-                            let formatted_str = self.build_format(&s.value(), s.span());
-                            code = Some(formatted_str);
-                        }
-                        "applicability" => {
-                            applicability = match applicability {
-                                Some(v) => {
-                                    span_err(
-                                        span,
-                                        "applicability cannot be set in both the field and \
-                                         attribute",
-                                    )
-                                    .emit();
-                                    Some(v)
-                                }
-                                None => match Applicability::from_str(&s.value()) {
-                                    Ok(v) => Some(quote! { #v }),
-                                    Err(()) => {
-                                        span_err(span, "invalid applicability").emit();
-                                        None
-                                    }
-                                },
-                            }
-                        }
-                        _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                            diag.help(
-                                "only `message`, `code` and `applicability` are valid field \
-                                 attributes",
-                            )
-                        }),
-                    }
+                if let Some((static_applicability, span)) = static_applicability {
+                    applicability.set_once(quote! { #static_applicability }, span);
                 }
-                _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                    if matches!(meta, Meta::Path(_)) {
-                        diag.help("a diagnostic slug must be the first argument to the attribute")
-                    } else {
-                        diag
-                    }
-                }),
+
+                let applicability = applicability
+                    .value()
+                    .unwrap_or_else(|| quote! { rustc_errors::Applicability::Unspecified });
+                let style = suggestion_kind.to_suggestion_style();
+
+                Ok(quote! {
+                    #diag.span_suggestion_with_style(
+                        #span_field,
+                        rustc_errors::fluent::#slug,
+                        #code,
+                        #applicability,
+                        #style
+                    );
+                })
             }
+            SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(),
         }
-
-        let applicability =
-            applicability.unwrap_or_else(|| quote!(rustc_errors::Applicability::Unspecified));
-
-        let name = path.segments.last().unwrap().ident.to_string();
-        let method = format_ident!("span_{}", name);
-
-        let msg = msg.unwrap_or_else(|| parse_quote! { _subdiag::suggestion });
-        let msg = quote! { rustc_errors::fluent::#msg };
-        let code = code.unwrap_or_else(|| quote! { String::new() });
-
-        Ok(quote! { #diag.#method(#span_field, #msg, #code, #applicability); })
     }
 
     /// Adds a spanned subdiagnostic by generating a `diag.span_$kind` call with the current slug
@@ -561,7 +412,7 @@ impl DiagnosticDeriveBuilder {
     fn span_and_applicability_of_ty(
         &self,
         info: FieldInfo<'_>,
-    ) -> Result<(TokenStream, Option<TokenStream>), DiagnosticDeriveError> {
+    ) -> Result<(TokenStream, SpannedOption<TokenStream>), DiagnosticDeriveError> {
         match &info.ty {
             // If `ty` is `Span` w/out applicability, then use `Applicability::Unspecified`.
             ty @ Type::Path(..) if type_matches_path(ty, &["rustc_span", "Span"]) => {
@@ -573,46 +424,37 @@ impl DiagnosticDeriveBuilder {
                 let mut span_idx = None;
                 let mut applicability_idx = None;
 
+                fn type_err(span: &Span) -> Result<!, DiagnosticDeriveError> {
+                    span_err(span.unwrap(), "wrong types for suggestion")
+                        .help(
+                            "`#[suggestion(...)]` on a tuple field must be applied to fields \
+                             of type `(Span, Applicability)`",
+                        )
+                        .emit();
+                    Err(DiagnosticDeriveError::ErrorHandled)
+                }
+
                 for (idx, elem) in tup.elems.iter().enumerate() {
                     if type_matches_path(elem, &["rustc_span", "Span"]) {
-                        if span_idx.is_none() {
-                            span_idx = Some(syn::Index::from(idx));
-                        } else {
-                            throw_span_err!(
-                                info.span.unwrap(),
-                                "type of field annotated with `#[suggestion(...)]` contains more \
-                                 than one `Span`"
-                            );
-                        }
+                        span_idx.set_once(syn::Index::from(idx), elem.span().unwrap());
                     } else if type_matches_path(elem, &["rustc_errors", "Applicability"]) {
-                        if applicability_idx.is_none() {
-                            applicability_idx = Some(syn::Index::from(idx));
-                        } else {
-                            throw_span_err!(
-                                info.span.unwrap(),
-                                "type of field annotated with `#[suggestion(...)]` contains more \
-                                 than one Applicability"
-                            );
-                        }
+                        applicability_idx.set_once(syn::Index::from(idx), elem.span().unwrap());
+                    } else {
+                        type_err(&elem.span())?;
                     }
                 }
 
-                if let Some(span_idx) = span_idx {
-                    let binding = &info.binding.binding;
-                    let span = quote!(#binding.#span_idx);
-                    let applicability = applicability_idx
-                        .map(|applicability_idx| quote!(#binding.#applicability_idx))
-                        .unwrap_or_else(|| quote!(rustc_errors::Applicability::Unspecified));
+                let Some((span_idx, _)) = span_idx else {
+                    type_err(&tup.span())?;
+                };
+                let Some((applicability_idx, applicability_span)) = applicability_idx else {
+                    type_err(&tup.span())?;
+                };
+                let binding = &info.binding.binding;
+                let span = quote!(#binding.#span_idx);
+                let applicability = quote!(#binding.#applicability_idx);
 
-                    return Ok((span, Some(applicability)));
-                }
-
-                throw_span_err!(info.span.unwrap(), "wrong types for suggestion", |diag| {
-                    diag.help(
-                        "`#[suggestion(...)]` on a tuple field must be applied to fields of type \
-                         `(Span, Applicability)`",
-                    )
-                });
+                Ok((span, Some((applicability, applicability_span))))
             }
             // If `ty` isn't a `Span` or `(Span, Applicability)` then emit an error.
             _ => throw_span_err!(info.span.unwrap(), "wrong field type for suggestion", |diag| {
diff --git a/compiler/rustc_macros/src/diagnostics/mod.rs b/compiler/rustc_macros/src/diagnostics/mod.rs
index 2ff21e18ff85..4166816b5e3c 100644
--- a/compiler/rustc_macros/src/diagnostics/mod.rs
+++ b/compiler/rustc_macros/src/diagnostics/mod.rs
@@ -5,14 +5,14 @@ mod fluent;
 mod subdiagnostic;
 mod utils;
 
-use diagnostic::{LintDiagnosticDerive, SessionDiagnosticDerive};
+use diagnostic::{DiagnosticDerive, LintDiagnosticDerive};
 pub(crate) use fluent::fluent_messages;
 use proc_macro2::TokenStream;
 use quote::format_ident;
-use subdiagnostic::SessionSubdiagnosticDerive;
+use subdiagnostic::SubdiagnosticDerive;
 use synstructure::Structure;
 
-/// Implements `#[derive(SessionDiagnostic)]`, which allows for errors to be specified as a struct,
+/// Implements `#[derive(Diagnostic)]`, which allows for errors to be specified as a struct,
 /// independent from the actual diagnostics emitting code.
 ///
 /// ```ignore (rust)
@@ -22,7 +22,7 @@ use synstructure::Structure;
 /// # use rustc_span::{symbol::Ident, Span};
 /// # extern crate rust_middle;
 /// # use rustc_middle::ty::Ty;
-/// #[derive(SessionDiagnostic)]
+/// #[derive(Diagnostic)]
 /// #[diag(borrowck::move_out_of_borrow, code = "E0505")]
 /// pub struct MoveOutOfBorrowError<'tcx> {
 ///     pub name: Ident,
@@ -56,10 +56,10 @@ use synstructure::Structure;
 /// });
 /// ```
 ///
-/// See rustc dev guide for more examples on using the `#[derive(SessionDiagnostic)]`:
+/// See rustc dev guide for more examples on using the `#[derive(Diagnostic)]`:
 /// <https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html>
 pub fn session_diagnostic_derive(s: Structure<'_>) -> TokenStream {
-    SessionDiagnosticDerive::new(format_ident!("diag"), format_ident!("sess"), s).into_tokens()
+    DiagnosticDerive::new(format_ident!("diag"), format_ident!("handler"), s).into_tokens()
 }
 
 /// Implements `#[derive(LintDiagnostic)]`, which allows for lints to be specified as a struct,
@@ -103,17 +103,17 @@ pub fn session_diagnostic_derive(s: Structure<'_>) -> TokenStream {
 /// ```
 ///
 /// See rustc dev guide for more examples on using the `#[derive(LintDiagnostic)]`:
-/// <https://rustc-dev-guide.rust-lang.org/diagnostics/sessiondiagnostic.html>
+/// <https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html#reference>
 pub fn lint_diagnostic_derive(s: Structure<'_>) -> TokenStream {
     LintDiagnosticDerive::new(format_ident!("diag"), s).into_tokens()
 }
 
-/// Implements `#[derive(SessionSubdiagnostic)]`, which allows for labels, notes, helps and
+/// Implements `#[derive(Subdiagnostic)]`, which allows for labels, notes, helps and
 /// suggestions to be specified as a structs or enums, independent from the actual diagnostics
 /// emitting code or diagnostic derives.
 ///
 /// ```ignore (rust)
-/// #[derive(SessionSubdiagnostic)]
+/// #[derive(Subdiagnostic)]
 /// pub enum ExpectedIdentifierLabel<'tcx> {
 ///     #[label(parser::expected_identifier)]
 ///     WithoutFound {
@@ -128,7 +128,7 @@ pub fn lint_diagnostic_derive(s: Structure<'_>) -> TokenStream {
 ///     }
 /// }
 ///
-/// #[derive(SessionSubdiagnostic)]
+/// #[derive(Subdiagnostic)]
 /// #[suggestion_verbose(parser::raw_identifier)]
 /// pub struct RawIdentifierSuggestion<'tcx> {
 ///     #[primary_span]
@@ -155,5 +155,5 @@ pub fn lint_diagnostic_derive(s: Structure<'_>) -> TokenStream {
 /// diag.subdiagnostic(RawIdentifierSuggestion { span, applicability, ident });
 /// ```
 pub fn session_subdiagnostic_derive(s: Structure<'_>) -> TokenStream {
-    SessionSubdiagnosticDerive::new(s).into_tokens()
+    SubdiagnosticDerive::new(s).into_tokens()
 }
diff --git a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
index 8b40e295bd8a..6545ae086b15 100644
--- a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
@@ -4,113 +4,32 @@ use crate::diagnostics::error::{
     span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err, DiagnosticDeriveError,
 };
 use crate::diagnostics::utils::{
-    report_error_if_not_applied_to_applicability, report_error_if_not_applied_to_span,
-    Applicability, FieldInfo, FieldInnerTy, HasFieldMap, SetOnce,
+    report_error_if_not_applied_to_applicability, report_error_if_not_applied_to_span, FieldInfo,
+    FieldInnerTy, HasFieldMap, SetOnce,
 };
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote};
 use std::collections::HashMap;
-use std::fmt;
-use std::str::FromStr;
 use syn::{spanned::Spanned, Attribute, Meta, MetaList, MetaNameValue, NestedMeta, Path};
 use synstructure::{BindingInfo, Structure, VariantInfo};
 
-/// Which kind of suggestion is being created?
-#[derive(Clone, Copy)]
-enum SubdiagnosticSuggestionKind {
-    /// `#[suggestion]`
-    Normal,
-    /// `#[suggestion_short]`
-    Short,
-    /// `#[suggestion_hidden]`
-    Hidden,
-    /// `#[suggestion_verbose]`
-    Verbose,
-}
-
-impl FromStr for SubdiagnosticSuggestionKind {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "" => Ok(SubdiagnosticSuggestionKind::Normal),
-            "_short" => Ok(SubdiagnosticSuggestionKind::Short),
-            "_hidden" => Ok(SubdiagnosticSuggestionKind::Hidden),
-            "_verbose" => Ok(SubdiagnosticSuggestionKind::Verbose),
-            _ => Err(()),
-        }
-    }
-}
-
-impl SubdiagnosticSuggestionKind {
-    pub fn to_suggestion_style(&self) -> TokenStream {
-        match self {
-            SubdiagnosticSuggestionKind::Normal => {
-                quote! { rustc_errors::SuggestionStyle::ShowCode }
-            }
-            SubdiagnosticSuggestionKind::Short => {
-                quote! { rustc_errors::SuggestionStyle::HideCodeInline }
-            }
-            SubdiagnosticSuggestionKind::Hidden => {
-                quote! { rustc_errors::SuggestionStyle::HideCodeAlways }
-            }
-            SubdiagnosticSuggestionKind::Verbose => {
-                quote! { rustc_errors::SuggestionStyle::ShowAlways }
-            }
-        }
-    }
-}
-
-/// Which kind of subdiagnostic is being created from a variant?
-#[derive(Clone)]
-enum SubdiagnosticKind {
-    /// `#[label(...)]`
-    Label,
-    /// `#[note(...)]`
-    Note,
-    /// `#[help(...)]`
-    Help,
-    /// `#[warning(...)]`
-    Warn,
-    /// `#[suggestion{,_short,_hidden,_verbose}]`
-    Suggestion { suggestion_kind: SubdiagnosticSuggestionKind, code: TokenStream },
-    /// `#[multipart_suggestion{,_short,_hidden,_verbose}]`
-    MultipartSuggestion { suggestion_kind: SubdiagnosticSuggestionKind },
-}
-
-impl quote::IdentFragment for SubdiagnosticKind {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            SubdiagnosticKind::Label => write!(f, "label"),
-            SubdiagnosticKind::Note => write!(f, "note"),
-            SubdiagnosticKind::Help => write!(f, "help"),
-            SubdiagnosticKind::Warn => write!(f, "warn"),
-            SubdiagnosticKind::Suggestion { .. } => write!(f, "suggestion_with_style"),
-            SubdiagnosticKind::MultipartSuggestion { .. } => {
-                write!(f, "multipart_suggestion_with_style")
-            }
-        }
-    }
-
-    fn span(&self) -> Option<proc_macro2::Span> {
-        None
-    }
-}
+use super::error::invalid_attr;
+use super::utils::{SpannedOption, SubdiagnosticKind};
 
 /// The central struct for constructing the `add_to_diagnostic` method from an annotated struct.
-pub(crate) struct SessionSubdiagnosticDerive<'a> {
+pub(crate) struct SubdiagnosticDerive<'a> {
     structure: Structure<'a>,
     diag: syn::Ident,
 }
 
-impl<'a> SessionSubdiagnosticDerive<'a> {
+impl<'a> SubdiagnosticDerive<'a> {
     pub(crate) fn new(structure: Structure<'a>) -> Self {
         let diag = format_ident!("diag");
         Self { structure, diag }
     }
 
     pub(crate) fn into_tokens(self) -> TokenStream {
-        let SessionSubdiagnosticDerive { mut structure, diag } = self;
+        let SubdiagnosticDerive { mut structure, diag } = self;
         let implementation = {
             let ast = structure.ast();
             let span = ast.span().unwrap();
@@ -119,7 +38,7 @@ impl<'a> SessionSubdiagnosticDerive<'a> {
                 syn::Data::Union(..) => {
                     span_err(
                         span,
-                        "`#[derive(SessionSubdiagnostic)]` can only be used on structs and enums",
+                        "`#[derive(Subdiagnostic)]` can only be used on structs and enums",
                     );
                 }
             }
@@ -146,7 +65,7 @@ impl<'a> SessionSubdiagnosticDerive<'a> {
                     }
                 }
 
-                let mut builder = SessionSubdiagnosticDeriveBuilder {
+                let mut builder = SubdiagnosticDeriveBuilder {
                     diag: &diag,
                     variant,
                     span,
@@ -166,7 +85,7 @@ impl<'a> SessionSubdiagnosticDerive<'a> {
         };
 
         let ret = structure.gen_impl(quote! {
-            gen impl rustc_errors::AddSubdiagnostic for @Self {
+            gen impl rustc_errors::AddToDiagnostic for @Self {
                 fn add_to_diagnostic(self, #diag: &mut rustc_errors::Diagnostic) {
                     use rustc_errors::{Applicability, IntoDiagnosticArg};
                     #implementation
@@ -178,10 +97,10 @@ impl<'a> SessionSubdiagnosticDerive<'a> {
 }
 
 /// Tracks persistent information required for building up the call to add to the diagnostic
-/// for the final generated method. This is a separate struct to `SessionSubdiagnosticDerive`
+/// for the final generated method. This is a separate struct to `SubdiagnosticDerive`
 /// only to be able to destructure and split `self.builder` and the `self.structure` up to avoid a
 /// double mut borrow later on.
-struct SessionSubdiagnosticDeriveBuilder<'a> {
+struct SubdiagnosticDeriveBuilder<'a> {
     /// The identifier to use for the generated `DiagnosticBuilder` instance.
     diag: &'a syn::Ident,
 
@@ -195,152 +114,73 @@ struct SessionSubdiagnosticDeriveBuilder<'a> {
     fields: HashMap<String, TokenStream>,
 
     /// Identifier for the binding to the `#[primary_span]` field.
-    span_field: Option<(proc_macro2::Ident, proc_macro::Span)>,
-    /// If a suggestion, the identifier for the binding to the `#[applicability]` field or a
-    /// `rustc_errors::Applicability::*` variant directly.
-    applicability: Option<(TokenStream, proc_macro::Span)>,
+    span_field: SpannedOption<proc_macro2::Ident>,
+
+    /// The binding to the `#[applicability]` field, if present.
+    applicability: SpannedOption<TokenStream>,
 
     /// Set to true when a `#[suggestion_part]` field is encountered, used to generate an error
     /// during finalization if still `false`.
     has_suggestion_parts: bool,
 }
 
-impl<'a> HasFieldMap for SessionSubdiagnosticDeriveBuilder<'a> {
+impl<'a> HasFieldMap for SubdiagnosticDeriveBuilder<'a> {
     fn get_field_binding(&self, field: &String) -> Option<&TokenStream> {
         self.fields.get(field)
     }
 }
 
-impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
-    fn identify_kind(
-        &mut self,
-    ) -> Result<Option<(SubdiagnosticKind, Path)>, DiagnosticDeriveError> {
-        let mut kind_slug = None;
+/// Provides frequently-needed information about the diagnostic kinds being derived for this type.
+#[derive(Clone, Copy, Debug)]
+struct KindsStatistics {
+    has_multipart_suggestion: bool,
+    all_multipart_suggestions: bool,
+    has_normal_suggestion: bool,
+    all_applicabilities_static: bool,
+}
+
+impl<'a> FromIterator<&'a SubdiagnosticKind> for KindsStatistics {
+    fn from_iter<T: IntoIterator<Item = &'a SubdiagnosticKind>>(kinds: T) -> Self {
+        let mut ret = Self {
+            has_multipart_suggestion: false,
+            all_multipart_suggestions: true,
+            has_normal_suggestion: false,
+            all_applicabilities_static: true,
+        };
+
+        for kind in kinds {
+            if let SubdiagnosticKind::MultipartSuggestion { applicability: None, .. }
+            | SubdiagnosticKind::Suggestion { applicability: None, .. } = kind
+            {
+                ret.all_applicabilities_static = false;
+            }
+            if let SubdiagnosticKind::MultipartSuggestion { .. } = kind {
+                ret.has_multipart_suggestion = true;
+            } else {
+                ret.all_multipart_suggestions = false;
+            }
+
+            if let SubdiagnosticKind::Suggestion { .. } = kind {
+                ret.has_normal_suggestion = true;
+            }
+        }
+        ret
+    }
+}
+
+impl<'a> SubdiagnosticDeriveBuilder<'a> {
+    fn identify_kind(&mut self) -> Result<Vec<(SubdiagnosticKind, Path)>, DiagnosticDeriveError> {
+        let mut kind_slugs = vec![];
 
         for attr in self.variant.ast().attrs {
-            let span = attr.span().unwrap();
+            let (kind, slug) = SubdiagnosticKind::from_attr(attr, self)?;
 
-            let name = attr.path.segments.last().unwrap().ident.to_string();
-            let name = name.as_str();
+            let Some(slug) = slug else {
+                let name = attr.path.segments.last().unwrap().ident.to_string();
+                let name = name.as_str();
 
-            let meta = attr.parse_meta()?;
-            let Meta::List(MetaList { ref nested, .. }) = meta else {
-                throw_invalid_attr!(attr, &meta);
-            };
-
-            let mut kind = match name {
-                "label" => SubdiagnosticKind::Label,
-                "note" => SubdiagnosticKind::Note,
-                "help" => SubdiagnosticKind::Help,
-                "warning" => SubdiagnosticKind::Warn,
-                _ => {
-                    if let Some(suggestion_kind) =
-                        name.strip_prefix("suggestion").and_then(|s| s.parse().ok())
-                    {
-                        SubdiagnosticKind::Suggestion { suggestion_kind, code: TokenStream::new() }
-                    } else if let Some(suggestion_kind) =
-                        name.strip_prefix("multipart_suggestion").and_then(|s| s.parse().ok())
-                    {
-                        SubdiagnosticKind::MultipartSuggestion { suggestion_kind }
-                    } else {
-                        throw_invalid_attr!(attr, &meta);
-                    }
-                }
-            };
-
-            let mut slug = None;
-            let mut code = None;
-
-            let mut nested_iter = nested.into_iter();
-            if let Some(nested_attr) = nested_iter.next() {
-                match nested_attr {
-                    NestedMeta::Meta(Meta::Path(path)) => {
-                        slug.set_once((path.clone(), span));
-                    }
-                    NestedMeta::Meta(meta @ Meta::NameValue(_))
-                        if matches!(
-                            meta.path().segments.last().unwrap().ident.to_string().as_str(),
-                            "code" | "applicability"
-                        ) =>
-                    {
-                        // Don't error for valid follow-up attributes.
-                    }
-                    nested_attr => {
-                        throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                            diag.help(
-                                "first argument of the attribute should be the diagnostic \
-                                 slug",
-                            )
-                        })
-                    }
-                };
-            }
-
-            for nested_attr in nested_iter {
-                let meta = match nested_attr {
-                    NestedMeta::Meta(ref meta) => meta,
-                    _ => throw_invalid_nested_attr!(attr, &nested_attr),
-                };
-
-                let span = meta.span().unwrap();
-                let nested_name = meta.path().segments.last().unwrap().ident.to_string();
-                let nested_name = nested_name.as_str();
-
-                let value = match meta {
-                    Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(value), .. }) => value,
-                    Meta::Path(_) => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                        diag.help("a diagnostic slug must be the first argument to the attribute")
-                    }),
-                    _ => throw_invalid_nested_attr!(attr, &nested_attr),
-                };
-
-                match nested_name {
-                    "code" => {
-                        if matches!(kind, SubdiagnosticKind::Suggestion { .. }) {
-                            let formatted_str = self.build_format(&value.value(), value.span());
-                            code.set_once((formatted_str, span));
-                        } else {
-                            span_err(
-                                span,
-                                &format!(
-                                    "`code` is not a valid nested attribute of a `{}` attribute",
-                                    name
-                                ),
-                            )
-                            .emit();
-                        }
-                    }
-                    "applicability" => {
-                        if matches!(
-                            kind,
-                            SubdiagnosticKind::Suggestion { .. }
-                                | SubdiagnosticKind::MultipartSuggestion { .. }
-                        ) {
-                            let value =
-                                Applicability::from_str(&value.value()).unwrap_or_else(|()| {
-                                    span_err(span, "invalid applicability").emit();
-                                    Applicability::Unspecified
-                                });
-                            self.applicability.set_once((quote! { #value }, span));
-                        } else {
-                            span_err(
-                                span,
-                                &format!(
-                                    "`applicability` is not a valid nested attribute of a `{}` attribute",
-                                    name
-                                )
-                            ).emit();
-                        }
-                    }
-                    _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                        diag.help("only `code` and `applicability` are valid nested attributes")
-                    }),
-                }
-            }
-
-            let Some((slug, _)) = slug else {
                 throw_span_err!(
-                    span,
+                    attr.span().unwrap(),
                     &format!(
                         "diagnostic slug must be first argument of a `#[{}(...)]` attribute",
                         name
@@ -348,24 +188,10 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
                 );
             };
 
-            match kind {
-                SubdiagnosticKind::Suggestion { code: ref mut code_field, .. } => {
-                    let Some((code, _)) = code else {
-                        throw_span_err!(span, "suggestion without `code = \"...\"`");
-                    };
-                    *code_field = code;
-                }
-                SubdiagnosticKind::Label
-                | SubdiagnosticKind::Note
-                | SubdiagnosticKind::Help
-                | SubdiagnosticKind::Warn
-                | SubdiagnosticKind::MultipartSuggestion { .. } => {}
-            }
-
-            kind_slug.set_once(((kind, slug), span))
+            kind_slugs.push((kind, slug));
         }
 
-        Ok(kind_slug.map(|(kind_slug, _)| kind_slug))
+        Ok(kind_slugs)
     }
 
     /// Generates the code for a field with no attributes.
@@ -387,7 +213,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
     fn generate_field_attr_code(
         &mut self,
         binding: &BindingInfo<'_>,
-        kind: &SubdiagnosticKind,
+        kind_stats: KindsStatistics,
     ) -> TokenStream {
         let ast = binding.ast();
         assert!(ast.attrs.len() > 0, "field without attributes generating attr code");
@@ -405,7 +231,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
                 };
 
                 let generated = self
-                    .generate_field_code_inner(kind, attr, info)
+                    .generate_field_code_inner(kind_stats, attr, info)
                     .unwrap_or_else(|v| v.to_compile_error());
 
                 inner_ty.with(binding, generated)
@@ -415,15 +241,15 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
 
     fn generate_field_code_inner(
         &mut self,
-        kind: &SubdiagnosticKind,
+        kind_stats: KindsStatistics,
         attr: &Attribute,
         info: FieldInfo<'_>,
     ) -> Result<TokenStream, DiagnosticDeriveError> {
         let meta = attr.parse_meta()?;
         match meta {
-            Meta::Path(path) => self.generate_field_code_inner_path(kind, attr, info, path),
+            Meta::Path(path) => self.generate_field_code_inner_path(kind_stats, attr, info, path),
             Meta::List(list @ MetaList { .. }) => {
-                self.generate_field_code_inner_list(kind, attr, info, list)
+                self.generate_field_code_inner_list(kind_stats, attr, info, list)
             }
             _ => throw_invalid_attr!(attr, &meta),
         }
@@ -432,7 +258,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
     /// Generates the code for a `[Meta::Path]`-like attribute on a field (e.g. `#[primary_span]`).
     fn generate_field_code_inner_path(
         &mut self,
-        kind: &SubdiagnosticKind,
+        kind_stats: KindsStatistics,
         attr: &Attribute,
         info: FieldInfo<'_>,
         path: Path,
@@ -445,71 +271,78 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
         match name {
             "skip_arg" => Ok(quote! {}),
             "primary_span" => {
-                if matches!(kind, SubdiagnosticKind::MultipartSuggestion { .. }) {
-                    throw_invalid_attr!(attr, &Meta::Path(path), |diag| {
-                        diag.help(
+                if kind_stats.has_multipart_suggestion {
+                    invalid_attr(attr, &Meta::Path(path))
+                        .help(
                             "multipart suggestions use one or more `#[suggestion_part]`s rather \
                             than one `#[primary_span]`",
                         )
-                    })
+                        .emit();
+                } else {
+                    report_error_if_not_applied_to_span(attr, &info)?;
+
+                    let binding = info.binding.binding.clone();
+                    self.span_field.set_once(binding, span);
                 }
 
-                report_error_if_not_applied_to_span(attr, &info)?;
-
-                let binding = info.binding.binding.clone();
-                self.span_field.set_once((binding, span));
-
                 Ok(quote! {})
             }
             "suggestion_part" => {
                 self.has_suggestion_parts = true;
 
-                match kind {
-                    SubdiagnosticKind::MultipartSuggestion { .. } => {
-                        span_err(
-                            span,
-                            "`#[suggestion_part(...)]` attribute without `code = \"...\"`",
+                if kind_stats.has_multipart_suggestion {
+                    span_err(span, "`#[suggestion_part(...)]` attribute without `code = \"...\"`")
+                        .emit();
+                } else {
+                    invalid_attr(attr, &Meta::Path(path))
+                        .help(
+                            "`#[suggestion_part(...)]` is only valid in multipart suggestions, \
+                             use `#[primary_span]` instead",
                         )
                         .emit();
-                        Ok(quote! {})
-                    }
-                    SubdiagnosticKind::Label
-                    | SubdiagnosticKind::Note
-                    | SubdiagnosticKind::Help
-                    | SubdiagnosticKind::Warn
-                    | SubdiagnosticKind::Suggestion { .. } => {
-                        throw_invalid_attr!(attr, &Meta::Path(path), |diag| {
-                            diag.help(
-                                "`#[suggestion_part(...)]` is only valid in multipart suggestions, use `#[primary_span]` instead",
-                            )
-                        });
-                    }
                 }
+
+                Ok(quote! {})
             }
             "applicability" => {
-                if let SubdiagnosticKind::Suggestion { .. }
-                | SubdiagnosticKind::MultipartSuggestion { .. } = kind
-                {
+                if kind_stats.has_multipart_suggestion || kind_stats.has_normal_suggestion {
                     report_error_if_not_applied_to_applicability(attr, &info)?;
 
+                    if kind_stats.all_applicabilities_static {
+                        span_err(
+                            span,
+                            "`#[applicability]` has no effect if all `#[suggestion]`/\
+                             `#[multipart_suggestion]` attributes have a static \
+                             `applicability = \"...\"`",
+                        )
+                        .emit();
+                    }
                     let binding = info.binding.binding.clone();
-                    self.applicability.set_once((quote! { #binding }, span));
+                    self.applicability.set_once(quote! { #binding }, span);
                 } else {
                     span_err(span, "`#[applicability]` is only valid on suggestions").emit();
                 }
 
                 Ok(quote! {})
             }
-            _ => throw_invalid_attr!(attr, &Meta::Path(path), |diag| {
-                let span_attr = if let SubdiagnosticKind::MultipartSuggestion { .. } = kind {
-                    "suggestion_part"
-                } else {
-                    "primary_span"
-                };
-                diag.help(format!(
-                    "only `{span_attr}`, `applicability` and `skip_arg` are valid field attributes",
-                ))
-            }),
+            _ => {
+                let mut span_attrs = vec![];
+                if kind_stats.has_multipart_suggestion {
+                    span_attrs.push("suggestion_part");
+                }
+                if !kind_stats.all_multipart_suggestions {
+                    span_attrs.push("primary_span")
+                }
+
+                invalid_attr(attr, &Meta::Path(path))
+                    .help(format!(
+                        "only `{}`, `applicability` and `skip_arg` are valid field attributes",
+                        span_attrs.join(", ")
+                    ))
+                    .emit();
+
+                Ok(quote! {})
+            }
         }
     }
 
@@ -517,7 +350,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
     /// `#[suggestion_part(code = "...")]`).
     fn generate_field_code_inner_list(
         &mut self,
-        kind: &SubdiagnosticKind,
+        kind_stats: KindsStatistics,
         attr: &Attribute,
         info: FieldInfo<'_>,
         list: MetaList,
@@ -529,7 +362,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
 
         match name {
             "suggestion_part" => {
-                if !matches!(kind, SubdiagnosticKind::MultipartSuggestion { .. }) {
+                if !kind_stats.has_multipart_suggestion {
                     throw_invalid_attr!(attr, &Meta::List(list), |diag| {
                         diag.help(
                             "`#[suggestion_part(...)]` is only valid in multipart suggestions",
@@ -558,7 +391,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
                     match nested_name {
                         "code" => {
                             let formatted_str = self.build_format(&value.value(), value.span());
-                            code.set_once((formatted_str, span));
+                            code.set_once(formatted_str, span);
                         }
                         _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
                             diag.help("`code` is the only valid nested attribute")
@@ -576,35 +409,36 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
                 Ok(quote! { suggestions.push((#binding, #code)); })
             }
             _ => throw_invalid_attr!(attr, &Meta::List(list), |diag| {
-                let span_attr = if let SubdiagnosticKind::MultipartSuggestion { .. } = kind {
-                    "suggestion_part"
-                } else {
-                    "primary_span"
-                };
+                let mut span_attrs = vec![];
+                if kind_stats.has_multipart_suggestion {
+                    span_attrs.push("suggestion_part");
+                }
+                if !kind_stats.all_multipart_suggestions {
+                    span_attrs.push("primary_span")
+                }
                 diag.help(format!(
-                    "only `{span_attr}`, `applicability` and `skip_arg` are valid field attributes",
+                    "only `{}`, `applicability` and `skip_arg` are valid field attributes",
+                    span_attrs.join(", ")
                 ))
             }),
         }
     }
 
     pub fn into_tokens(&mut self) -> Result<TokenStream, DiagnosticDeriveError> {
-        let Some((kind, slug)) = self.identify_kind()? else {
+        let kind_slugs = self.identify_kind()?;
+        if kind_slugs.is_empty() {
             throw_span_err!(
                 self.variant.ast().ident.span().unwrap(),
                 "subdiagnostic kind not specified"
             );
         };
 
-        let init = match &kind {
-            SubdiagnosticKind::Label
-            | SubdiagnosticKind::Note
-            | SubdiagnosticKind::Help
-            | SubdiagnosticKind::Warn
-            | SubdiagnosticKind::Suggestion { .. } => quote! {},
-            SubdiagnosticKind::MultipartSuggestion { .. } => {
-                quote! { let mut suggestions = Vec::new(); }
-            }
+        let kind_stats: KindsStatistics = kind_slugs.iter().map(|(kind, _slug)| kind).collect();
+
+        let init = if kind_stats.has_multipart_suggestion {
+            quote! { let mut suggestions = Vec::new(); }
+        } else {
+            quote! {}
         };
 
         let attr_args: TokenStream = self
@@ -612,58 +446,70 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
             .bindings()
             .iter()
             .filter(|binding| !binding.ast().attrs.is_empty())
-            .map(|binding| self.generate_field_attr_code(binding, &kind))
+            .map(|binding| self.generate_field_attr_code(binding, kind_stats))
             .collect();
 
-        let span_field = self.span_field.as_ref().map(|(span, _)| span);
-        let applicability = self.applicability.take().map_or_else(
-            || quote! { rustc_errors::Applicability::Unspecified },
-            |(applicability, _)| applicability,
-        );
+        let span_field = self.span_field.value_ref();
 
         let diag = &self.diag;
-        let name = format_ident!("{}{}", if span_field.is_some() { "span_" } else { "" }, kind);
-        let message = quote! { rustc_errors::fluent::#slug };
-        let call = match kind {
-            SubdiagnosticKind::Suggestion { suggestion_kind, code } => {
-                if let Some(span) = span_field {
+        let mut calls = TokenStream::new();
+        for (kind, slug) in kind_slugs {
+            let name = format_ident!("{}{}", if span_field.is_some() { "span_" } else { "" }, kind);
+            let message = quote! { rustc_errors::fluent::#slug };
+            let call = match kind {
+                SubdiagnosticKind::Suggestion { suggestion_kind, applicability, code } => {
+                    let applicability = applicability
+                        .value()
+                        .map(|a| quote! { #a })
+                        .or_else(|| self.applicability.take().value())
+                        .unwrap_or_else(|| quote! { rustc_errors::Applicability::Unspecified });
+
+                    if let Some(span) = span_field {
+                        let style = suggestion_kind.to_suggestion_style();
+
+                        quote! { #diag.#name(#span, #message, #code, #applicability, #style); }
+                    } else {
+                        span_err(self.span, "suggestion without `#[primary_span]` field").emit();
+                        quote! { unreachable!(); }
+                    }
+                }
+                SubdiagnosticKind::MultipartSuggestion { suggestion_kind, applicability } => {
+                    let applicability = applicability
+                        .value()
+                        .map(|a| quote! { #a })
+                        .or_else(|| self.applicability.take().value())
+                        .unwrap_or_else(|| quote! { rustc_errors::Applicability::Unspecified });
+
+                    if !self.has_suggestion_parts {
+                        span_err(
+                            self.span,
+                            "multipart suggestion without any `#[suggestion_part(...)]` fields",
+                        )
+                        .emit();
+                    }
+
                     let style = suggestion_kind.to_suggestion_style();
 
-                    quote! { #diag.#name(#span, #message, #code, #applicability, #style); }
-                } else {
-                    span_err(self.span, "suggestion without `#[primary_span]` field").emit();
-                    quote! { unreachable!(); }
+                    quote! { #diag.#name(#message, suggestions, #applicability, #style); }
                 }
-            }
-            SubdiagnosticKind::MultipartSuggestion { suggestion_kind } => {
-                if !self.has_suggestion_parts {
-                    span_err(
-                        self.span,
-                        "multipart suggestion without any `#[suggestion_part(...)]` fields",
-                    )
-                    .emit();
+                SubdiagnosticKind::Label => {
+                    if let Some(span) = span_field {
+                        quote! { #diag.#name(#span, #message); }
+                    } else {
+                        span_err(self.span, "label without `#[primary_span]` field").emit();
+                        quote! { unreachable!(); }
+                    }
                 }
-
-                let style = suggestion_kind.to_suggestion_style();
-
-                quote! { #diag.#name(#message, suggestions, #applicability, #style); }
-            }
-            SubdiagnosticKind::Label => {
-                if let Some(span) = span_field {
-                    quote! { #diag.#name(#span, #message); }
-                } else {
-                    span_err(self.span, "label without `#[primary_span]` field").emit();
-                    quote! { unreachable!(); }
+                _ => {
+                    if let Some(span) = span_field {
+                        quote! { #diag.#name(#span, #message); }
+                    } else {
+                        quote! { #diag.#name(#message); }
+                    }
                 }
-            }
-            _ => {
-                if let Some(span) = span_field {
-                    quote! { #diag.#name(#span, #message); }
-                } else {
-                    quote! { #diag.#name(#message); }
-                }
-            }
-        };
+            };
+            calls.extend(call);
+        }
 
         let plain_args: TokenStream = self
             .variant
@@ -676,7 +522,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
         Ok(quote! {
             #init
             #attr_args
-            #call
+            #calls
             #plain_args
         })
     }
diff --git a/compiler/rustc_macros/src/diagnostics/utils.rs b/compiler/rustc_macros/src/diagnostics/utils.rs
index ad9ecd39b9e8..a31bda9ca0de 100644
--- a/compiler/rustc_macros/src/diagnostics/utils.rs
+++ b/compiler/rustc_macros/src/diagnostics/utils.rs
@@ -1,12 +1,18 @@
-use crate::diagnostics::error::{span_err, throw_span_err, DiagnosticDeriveError};
+use crate::diagnostics::error::{
+    span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err, DiagnosticDeriveError,
+};
 use proc_macro::Span;
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote, ToTokens};
 use std::collections::{BTreeSet, HashMap};
+use std::fmt;
 use std::str::FromStr;
 use syn::{spanned::Spanned, Attribute, Meta, Type, TypeTuple};
+use syn::{MetaList, MetaNameValue, NestedMeta, Path};
 use synstructure::{BindingInfo, Structure};
 
+use super::error::invalid_nested_attr;
+
 /// Checks whether the type name of `ty` matches `name`.
 ///
 /// Given some struct at `a::b::c::Foo`, this will return true for `c::Foo`, `b::c::Foo`, or
@@ -172,13 +178,17 @@ pub(crate) struct FieldInfo<'a> {
 /// Small helper trait for abstracting over `Option` fields that contain a value and a `Span`
 /// for error reporting if they are set more than once.
 pub(crate) trait SetOnce<T> {
-    fn set_once(&mut self, _: (T, Span));
+    fn set_once(&mut self, value: T, span: Span);
 
     fn value(self) -> Option<T>;
+    fn value_ref(&self) -> Option<&T>;
 }
 
-impl<T> SetOnce<T> for Option<(T, Span)> {
-    fn set_once(&mut self, (value, span): (T, Span)) {
+/// An [`Option<T>`] that keeps track of the span that caused it to be set; used with [`SetOnce`].
+pub(super) type SpannedOption<T> = Option<(T, Span)>;
+
+impl<T> SetOnce<T> for SpannedOption<T> {
+    fn set_once(&mut self, value: T, span: Span) {
         match self {
             None => {
                 *self = Some((value, span));
@@ -194,6 +204,10 @@ impl<T> SetOnce<T> for Option<(T, Span)> {
     fn value(self) -> Option<T> {
         self.map(|(v, _)| v)
     }
+
+    fn value_ref(&self) -> Option<&T> {
+        self.as_ref().map(|(v, _)| v)
+    }
 }
 
 pub(crate) trait HasFieldMap {
@@ -303,6 +317,7 @@ pub(crate) trait HasFieldMap {
 
 /// `Applicability` of a suggestion - mirrors `rustc_errors::Applicability` - and used to represent
 /// the user's selection of applicability if specified in an attribute.
+#[derive(Clone, Copy)]
 pub(crate) enum Applicability {
     MachineApplicable,
     MaybeIncorrect,
@@ -359,3 +374,250 @@ pub(crate) fn build_field_mapping<'a>(structure: &Structure<'a>) -> HashMap<Stri
 
     fields_map
 }
+
+/// Possible styles for suggestion subdiagnostics.
+#[derive(Clone, Copy)]
+pub(super) enum SuggestionKind {
+    /// `#[suggestion]`
+    Normal,
+    /// `#[suggestion_short]`
+    Short,
+    /// `#[suggestion_hidden]`
+    Hidden,
+    /// `#[suggestion_verbose]`
+    Verbose,
+}
+
+impl FromStr for SuggestionKind {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "" => Ok(SuggestionKind::Normal),
+            "_short" => Ok(SuggestionKind::Short),
+            "_hidden" => Ok(SuggestionKind::Hidden),
+            "_verbose" => Ok(SuggestionKind::Verbose),
+            _ => Err(()),
+        }
+    }
+}
+
+impl SuggestionKind {
+    pub fn to_suggestion_style(&self) -> TokenStream {
+        match self {
+            SuggestionKind::Normal => {
+                quote! { rustc_errors::SuggestionStyle::ShowCode }
+            }
+            SuggestionKind::Short => {
+                quote! { rustc_errors::SuggestionStyle::HideCodeInline }
+            }
+            SuggestionKind::Hidden => {
+                quote! { rustc_errors::SuggestionStyle::HideCodeAlways }
+            }
+            SuggestionKind::Verbose => {
+                quote! { rustc_errors::SuggestionStyle::ShowAlways }
+            }
+        }
+    }
+}
+
+/// Types of subdiagnostics that can be created using attributes
+#[derive(Clone)]
+pub(super) enum SubdiagnosticKind {
+    /// `#[label(...)]`
+    Label,
+    /// `#[note(...)]`
+    Note,
+    /// `#[help(...)]`
+    Help,
+    /// `#[warning(...)]`
+    Warn,
+    /// `#[suggestion{,_short,_hidden,_verbose}]`
+    Suggestion {
+        suggestion_kind: SuggestionKind,
+        applicability: SpannedOption<Applicability>,
+        code: TokenStream,
+    },
+    /// `#[multipart_suggestion{,_short,_hidden,_verbose}]`
+    MultipartSuggestion {
+        suggestion_kind: SuggestionKind,
+        applicability: SpannedOption<Applicability>,
+    },
+}
+
+impl SubdiagnosticKind {
+    /// Constructs a `SubdiagnosticKind` from a field or type attribute such as `#[note]`,
+    /// `#[error(parser::add_paren)]` or `#[suggestion(code = "...")]`. Returns the
+    /// `SubdiagnosticKind` and the diagnostic slug, if specified.
+    pub(super) fn from_attr(
+        attr: &Attribute,
+        fields: &impl HasFieldMap,
+    ) -> Result<(SubdiagnosticKind, Option<Path>), DiagnosticDeriveError> {
+        let span = attr.span().unwrap();
+
+        let name = attr.path.segments.last().unwrap().ident.to_string();
+        let name = name.as_str();
+
+        let meta = attr.parse_meta()?;
+        let mut kind = match name {
+            "label" => SubdiagnosticKind::Label,
+            "note" => SubdiagnosticKind::Note,
+            "help" => SubdiagnosticKind::Help,
+            "warning" => SubdiagnosticKind::Warn,
+            _ => {
+                if let Some(suggestion_kind) =
+                    name.strip_prefix("suggestion").and_then(|s| s.parse().ok())
+                {
+                    SubdiagnosticKind::Suggestion {
+                        suggestion_kind,
+                        applicability: None,
+                        code: TokenStream::new(),
+                    }
+                } else if let Some(suggestion_kind) =
+                    name.strip_prefix("multipart_suggestion").and_then(|s| s.parse().ok())
+                {
+                    SubdiagnosticKind::MultipartSuggestion { suggestion_kind, applicability: None }
+                } else {
+                    throw_invalid_attr!(attr, &meta);
+                }
+            }
+        };
+
+        let nested = match meta {
+            Meta::List(MetaList { ref nested, .. }) => {
+                // An attribute with properties, such as `#[suggestion(code = "...")]` or
+                // `#[error(some::slug)]`
+                nested
+            }
+            Meta::Path(_) => {
+                // An attribute without a slug or other properties, such as `#[note]` - return
+                // without further processing.
+                //
+                // Only allow this if there are no mandatory properties, such as `code = "..."` in
+                // `#[suggestion(...)]`
+                match kind {
+                    SubdiagnosticKind::Label
+                    | SubdiagnosticKind::Note
+                    | SubdiagnosticKind::Help
+                    | SubdiagnosticKind::Warn
+                    | SubdiagnosticKind::MultipartSuggestion { .. } => return Ok((kind, None)),
+                    SubdiagnosticKind::Suggestion { .. } => {
+                        throw_span_err!(span, "suggestion without `code = \"...\"`")
+                    }
+                }
+            }
+            _ => {
+                throw_invalid_attr!(attr, &meta)
+            }
+        };
+
+        let mut code = None;
+
+        let mut nested_iter = nested.into_iter().peekable();
+
+        // Peek at the first nested attribute: if it's a slug path, consume it.
+        let slug = if let Some(NestedMeta::Meta(Meta::Path(path))) = nested_iter.peek() {
+            let path = path.clone();
+            // Advance the iterator.
+            nested_iter.next();
+            Some(path)
+        } else {
+            None
+        };
+
+        for nested_attr in nested_iter {
+            let meta = match nested_attr {
+                NestedMeta::Meta(ref meta) => meta,
+                NestedMeta::Lit(_) => {
+                    invalid_nested_attr(attr, &nested_attr).emit();
+                    continue;
+                }
+            };
+
+            let span = meta.span().unwrap();
+            let nested_name = meta.path().segments.last().unwrap().ident.to_string();
+            let nested_name = nested_name.as_str();
+
+            let value = match meta {
+                Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(value), .. }) => value,
+                Meta::Path(_) => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                    diag.help("a diagnostic slug must be the first argument to the attribute")
+                }),
+                _ => {
+                    invalid_nested_attr(attr, &nested_attr).emit();
+                    continue;
+                }
+            };
+
+            match (nested_name, &mut kind) {
+                ("code", SubdiagnosticKind::Suggestion { .. }) => {
+                    let formatted_str = fields.build_format(&value.value(), value.span());
+                    code.set_once(formatted_str, span);
+                }
+                (
+                    "applicability",
+                    SubdiagnosticKind::Suggestion { ref mut applicability, .. }
+                    | SubdiagnosticKind::MultipartSuggestion { ref mut applicability, .. },
+                ) => {
+                    let value = Applicability::from_str(&value.value()).unwrap_or_else(|()| {
+                        span_err(span, "invalid applicability").emit();
+                        Applicability::Unspecified
+                    });
+                    applicability.set_once(value, span);
+                }
+
+                // Invalid nested attribute
+                (_, SubdiagnosticKind::Suggestion { .. }) => {
+                    invalid_nested_attr(attr, &nested_attr)
+                        .help("only `code` and `applicability` are valid nested attributes")
+                        .emit();
+                }
+                (_, SubdiagnosticKind::MultipartSuggestion { .. }) => {
+                    invalid_nested_attr(attr, &nested_attr)
+                        .help("only `applicability` is a valid nested attributes")
+                        .emit()
+                }
+                _ => {
+                    invalid_nested_attr(attr, &nested_attr).emit();
+                }
+            }
+        }
+
+        match kind {
+            SubdiagnosticKind::Suggestion { code: ref mut code_field, .. } => {
+                *code_field = if let Some((code, _)) = code {
+                    code
+                } else {
+                    span_err(span, "suggestion without `code = \"...\"`").emit();
+                    quote! { "" }
+                }
+            }
+            SubdiagnosticKind::Label
+            | SubdiagnosticKind::Note
+            | SubdiagnosticKind::Help
+            | SubdiagnosticKind::Warn
+            | SubdiagnosticKind::MultipartSuggestion { .. } => {}
+        }
+
+        Ok((kind, slug))
+    }
+}
+
+impl quote::IdentFragment for SubdiagnosticKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            SubdiagnosticKind::Label => write!(f, "label"),
+            SubdiagnosticKind::Note => write!(f, "note"),
+            SubdiagnosticKind::Help => write!(f, "help"),
+            SubdiagnosticKind::Warn => write!(f, "warn"),
+            SubdiagnosticKind::Suggestion { .. } => write!(f, "suggestion_with_style"),
+            SubdiagnosticKind::MultipartSuggestion { .. } => {
+                write!(f, "multipart_suggestion_with_style")
+            }
+        }
+    }
+
+    fn span(&self) -> Option<proc_macro2::Span> {
+        None
+    }
+}
diff --git a/compiler/rustc_macros/src/lib.rs b/compiler/rustc_macros/src/lib.rs
index 20ee5dfc7279..36bda3e0f6bb 100644
--- a/compiler/rustc_macros/src/lib.rs
+++ b/compiler/rustc_macros/src/lib.rs
@@ -1,5 +1,4 @@
 #![feature(allow_internal_unstable)]
-#![feature(let_else)]
 #![feature(never_type)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_span)]
@@ -127,7 +126,7 @@ decl_derive!([TypeFoldable, attributes(type_foldable)] => type_foldable::type_fo
 decl_derive!([TypeVisitable, attributes(type_visitable)] => type_visitable::type_visitable_derive);
 decl_derive!([Lift, attributes(lift)] => lift::lift_derive);
 decl_derive!(
-    [SessionDiagnostic, attributes(
+    [Diagnostic, attributes(
         // struct attributes
         diag,
         help,
@@ -161,7 +160,7 @@ decl_derive!(
         suggestion_verbose)] => diagnostics::lint_diagnostic_derive
 );
 decl_derive!(
-    [SessionSubdiagnostic, attributes(
+    [Subdiagnostic, attributes(
         // struct/variant attributes
         label,
         help,
diff --git a/compiler/rustc_macros/src/query.rs b/compiler/rustc_macros/src/query.rs
index f93fe2d51950..d49926c90ca9 100644
--- a/compiler/rustc_macros/src/query.rs
+++ b/compiler/rustc_macros/src/query.rs
@@ -86,14 +86,11 @@ struct QueryModifiers {
     desc: (Option<Ident>, Punctuated<Expr, Token![,]>),
 
     /// Use this type for the in-memory cache.
-    storage: Option<Type>,
+    arena_cache: Option<Ident>,
 
     /// Cache the query to disk if the `Block` returns true.
     cache: Option<(Option<Pat>, Block)>,
 
-    /// Custom code to load the query from disk.
-    load_cached: Option<(Ident, Ident, Block)>,
-
     /// A cycle error for this query aborting the compilation with a fatal error.
     fatal_cycle: Option<Ident>,
 
@@ -120,8 +117,7 @@ struct QueryModifiers {
 }
 
 fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
-    let mut load_cached = None;
-    let mut storage = None;
+    let mut arena_cache = None;
     let mut cache = None;
     let mut desc = None;
     let mut fatal_cycle = None;
@@ -173,21 +169,8 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
             };
             let block = input.parse()?;
             try_insert!(cache = (args, block));
-        } else if modifier == "load_cached" {
-            // Parse a load_cached modifier like:
-            // `load_cached(tcx, id) { tcx.on_disk_cache.try_load_query_result(tcx, id) }`
-            let args;
-            parenthesized!(args in input);
-            let tcx = args.parse()?;
-            args.parse::<Token![,]>()?;
-            let id = args.parse()?;
-            let block = input.parse()?;
-            try_insert!(load_cached = (tcx, id, block));
-        } else if modifier == "storage" {
-            let args;
-            parenthesized!(args in input);
-            let ty = args.parse()?;
-            try_insert!(storage = ty);
+        } else if modifier == "arena_cache" {
+            try_insert!(arena_cache = modifier);
         } else if modifier == "fatal_cycle" {
             try_insert!(fatal_cycle = modifier);
         } else if modifier == "cycle_delay_bug" {
@@ -212,8 +195,7 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
         return Err(input.error("no description provided"));
     };
     Ok(QueryModifiers {
-        load_cached,
-        storage,
+        arena_cache,
         cache,
         desc,
         fatal_cycle,
@@ -262,20 +244,6 @@ fn add_query_description_impl(query: &Query, impls: &mut proc_macro2::TokenStrea
 
     // Find out if we should cache the query on disk
     let cache = if let Some((args, expr)) = modifiers.cache.as_ref() {
-        let try_load_from_disk = if let Some((tcx, id, block)) = modifiers.load_cached.as_ref() {
-            // Use custom code to load the query from disk
-            quote! {
-                const TRY_LOAD_FROM_DISK: Option<fn(QueryCtxt<'tcx>, SerializedDepNodeIndex) -> Option<Self::Value>>
-                    = Some(|#tcx, #id| { #block });
-            }
-        } else {
-            // Use the default code to load the query from disk
-            quote! {
-                const TRY_LOAD_FROM_DISK: Option<fn(QueryCtxt<'tcx>, SerializedDepNodeIndex) -> Option<Self::Value>>
-                    = Some(|tcx, id| tcx.on_disk_cache().as_ref()?.try_load_query_result(*tcx, id));
-            }
-        };
-
         let tcx = args.as_ref().map(|t| quote! { #t }).unwrap_or_else(|| quote! { _ });
         // expr is a `Block`, meaning that `{ #expr }` gets expanded
         // to `{ { stmts... } }`, which triggers the `unused_braces` lint.
@@ -285,20 +253,13 @@ fn add_query_description_impl(query: &Query, impls: &mut proc_macro2::TokenStrea
             fn cache_on_disk(#tcx: TyCtxt<'tcx>, #key: &Self::Key) -> bool {
                 #expr
             }
-
-            #try_load_from_disk
         }
     } else {
-        if modifiers.load_cached.is_some() {
-            panic!("load_cached modifier on query `{}` without a cache modifier", name);
-        }
         quote! {
             #[inline]
             fn cache_on_disk(_: TyCtxt<'tcx>, _: &Self::Key) -> bool {
                 false
             }
-
-            const TRY_LOAD_FROM_DISK: Option<fn(QueryCtxt<'tcx>, SerializedDepNodeIndex) -> Option<Self::Value>> = None;
         }
     };
 
@@ -328,7 +289,6 @@ pub fn rustc_queries(input: TokenStream) -> TokenStream {
 
     let mut query_stream = quote! {};
     let mut query_description_stream = quote! {};
-    let mut dep_node_def_stream = quote! {};
     let mut cached_queries = quote! {};
 
     for query in queries.0 {
@@ -347,42 +307,32 @@ pub fn rustc_queries(input: TokenStream) -> TokenStream {
 
         let mut attributes = Vec::new();
 
-        // Pass on the fatal_cycle modifier
-        if let Some(fatal_cycle) = &modifiers.fatal_cycle {
-            attributes.push(quote! { (#fatal_cycle) });
-        };
-        // Pass on the storage modifier
-        if let Some(ref ty) = modifiers.storage {
-            let span = ty.span();
-            attributes.push(quote_spanned! {span=> (storage #ty) });
-        };
-        // Pass on the cycle_delay_bug modifier
-        if let Some(cycle_delay_bug) = &modifiers.cycle_delay_bug {
-            attributes.push(quote! { (#cycle_delay_bug) });
-        };
-        // Pass on the no_hash modifier
-        if let Some(no_hash) = &modifiers.no_hash {
-            attributes.push(quote! { (#no_hash) });
-        };
-        // Pass on the anon modifier
-        if let Some(anon) = &modifiers.anon {
-            attributes.push(quote! { (#anon) });
-        };
-        // Pass on the eval_always modifier
-        if let Some(eval_always) = &modifiers.eval_always {
-            attributes.push(quote! { (#eval_always) });
-        };
-        // Pass on the depth_limit modifier
-        if let Some(depth_limit) = &modifiers.depth_limit {
-            attributes.push(quote! { (#depth_limit) });
-        };
-        // Pass on the separate_provide_extern modifier
-        if let Some(separate_provide_extern) = &modifiers.separate_provide_extern {
-            attributes.push(quote! { (#separate_provide_extern) });
+        macro_rules! passthrough {
+            ( $( $modifier:ident ),+ $(,)? ) => {
+                $( if let Some($modifier) = &modifiers.$modifier {
+                    attributes.push(quote! { (#$modifier) });
+                }; )+
+            }
         }
-        // Pass on the remap_env_constness modifier
-        if let Some(remap_env_constness) = &modifiers.remap_env_constness {
-            attributes.push(quote! { (#remap_env_constness) });
+
+        passthrough!(
+            fatal_cycle,
+            arena_cache,
+            cycle_delay_bug,
+            no_hash,
+            anon,
+            eval_always,
+            depth_limit,
+            separate_provide_extern,
+            remap_env_constness,
+        );
+
+        if modifiers.cache.is_some() {
+            attributes.push(quote! { (cache) });
+        }
+        // Pass on the cache modifier
+        if modifiers.cache.is_some() {
+            attributes.push(quote! { (cache) });
         }
 
         // This uses the span of the query definition for the commas,
@@ -393,45 +343,27 @@ pub fn rustc_queries(input: TokenStream) -> TokenStream {
         // be very useful.
         let span = name.span();
         let attribute_stream = quote_spanned! {span=> #(#attributes),*};
-        let doc_comments = query.doc_comments.iter();
+        let doc_comments = &query.doc_comments;
         // Add the query to the group
         query_stream.extend(quote! {
             #(#doc_comments)*
             [#attribute_stream] fn #name(#arg) #result,
         });
 
-        // Create a dep node for the query
-        dep_node_def_stream.extend(quote! {
-            [#attribute_stream] #name(#arg),
-        });
-
         add_query_description_impl(&query, &mut query_description_stream);
     }
 
     TokenStream::from(quote! {
         #[macro_export]
         macro_rules! rustc_query_append {
-            ($macro:ident !) => {
+            ($macro:ident! $( [$($other:tt)*] )?) => {
                 $macro! {
+                    $( $($other)* )?
                     #query_stream
                 }
             }
         }
-        macro_rules! rustc_dep_node_append {
-            ($macro:ident! [$($other:tt)*]) => {
-                $macro!(
-                    $($other)*
 
-                    #dep_node_def_stream
-                );
-            }
-        }
-        #[macro_export]
-        macro_rules! rustc_cached_queries {
-            ( $macro:ident! ) => {
-                $macro!(#cached_queries);
-            }
-        }
         #[macro_export]
         macro_rules! rustc_query_description {
             #query_description_stream
diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index 708d0b1fd8a3..cfcceecbef40 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -1,5 +1,9 @@
 //! Validates all used crates and extern libraries and loads their metadata
 
+use crate::errors::{
+    ConflictingGlobalAlloc, CrateNotPanicRuntime, GlobalAllocRequired, NoMultipleGlobalAlloc,
+    NoPanicStrategy, NoTransitiveNeedsDep, NotProfilerRuntime, ProfilerBuiltinsNeedsCore,
+};
 use crate::locator::{CrateError, CrateLocator, CratePaths};
 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
 
@@ -29,7 +33,6 @@ use proc_macro::bridge::client::ProcMacro;
 use std::ops::Fn;
 use std::path::Path;
 use std::{cmp, env};
-use tracing::{debug, info};
 
 #[derive(Clone)]
 pub struct CStore {
@@ -263,7 +266,7 @@ impl<'a> CrateLoader<'a> {
     fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
         for (cnum, data) in self.cstore.iter_crate_data() {
             if data.name() != name {
-                tracing::trace!("{} did not match {}", data.name(), name);
+                trace!("{} did not match {}", data.name(), name);
                 continue;
             }
 
@@ -746,15 +749,10 @@ impl<'a> CrateLoader<'a> {
         // Sanity check the loaded crate to ensure it is indeed a panic runtime
         // and the panic strategy is indeed what we thought it was.
         if !data.is_panic_runtime() {
-            self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
+            self.sess.emit_err(CrateNotPanicRuntime { crate_name: name });
         }
         if data.required_panic_strategy() != Some(desired_strategy) {
-            self.sess.err(&format!(
-                "the crate `{}` does not have the panic \
-                                    strategy `{}`",
-                name,
-                desired_strategy.desc()
-            ));
+            self.sess.emit_err(NoPanicStrategy { crate_name: name, strategy: desired_strategy });
         }
 
         self.cstore.injected_panic_runtime = Some(cnum);
@@ -774,10 +772,7 @@ impl<'a> CrateLoader<'a> {
 
         let name = Symbol::intern(&self.sess.opts.unstable_opts.profiler_runtime);
         if name == sym::profiler_builtins && self.sess.contains_name(&krate.attrs, sym::no_core) {
-            self.sess.err(
-                "`profiler_builtins` crate (required by compiler options) \
-                        is not compatible with crate attribute `#![no_core]`",
-            );
+            self.sess.emit_err(ProfilerBuiltinsNeedsCore);
         }
 
         let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else { return; };
@@ -785,18 +780,14 @@ impl<'a> CrateLoader<'a> {
 
         // Sanity check the loaded crate to ensure it is indeed a profiler runtime
         if !data.is_profiler_runtime() {
-            self.sess.err(&format!("the crate `{}` is not a profiler runtime", name));
+            self.sess.emit_err(NotProfilerRuntime { crate_name: name });
         }
     }
 
     fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
         self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
             [span1, span2, ..] => {
-                self.sess
-                    .struct_span_err(*span2, "cannot define multiple global allocators")
-                    .span_label(*span2, "cannot define a new global allocator")
-                    .span_label(*span1, "previous global allocator defined here")
-                    .emit();
+                self.sess.emit_err(NoMultipleGlobalAlloc { span2: *span2, span1: *span1 });
                 true
             }
             spans => !spans.is_empty(),
@@ -832,11 +823,10 @@ impl<'a> CrateLoader<'a> {
             if data.has_global_allocator() {
                 match global_allocator {
                     Some(other_crate) => {
-                        self.sess.err(&format!(
-                        "the `#[global_allocator]` in {} conflicts with global allocator in: {}",
-                        other_crate,
-                        data.name()
-                    ));
+                        self.sess.emit_err(ConflictingGlobalAlloc {
+                            crate_name: data.name(),
+                            other_crate_name: other_crate,
+                        });
                     }
                     None => global_allocator = Some(data.name()),
                 }
@@ -855,10 +845,7 @@ impl<'a> CrateLoader<'a> {
         if !self.sess.contains_name(&krate.attrs, sym::default_lib_allocator)
             && !self.cstore.iter_crate_data().any(|(_, data)| data.has_default_lib_allocator())
         {
-            self.sess.err(
-                "no global memory allocator found but one is required; link to std or add \
-                 `#[global_allocator]` to a static item that implements the GlobalAlloc trait",
-            );
+            self.sess.emit_err(GlobalAllocRequired);
         }
         self.cstore.allocator_kind = Some(AllocatorKind::Default);
     }
@@ -882,14 +869,11 @@ impl<'a> CrateLoader<'a> {
         for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
             let data = self.cstore.get_crate_data(dep);
             if needs_dep(&data) {
-                self.sess.err(&format!(
-                    "the crate `{}` cannot depend \
-                                        on a crate that needs {}, but \
-                                        it depends on `{}`",
-                    self.cstore.get_crate_data(krate).name(),
-                    what,
-                    data.name()
-                ));
+                self.sess.emit_err(NoTransitiveNeedsDep {
+                    crate_name: self.cstore.get_crate_data(krate).name(),
+                    needs_crate_name: what,
+                    deps_crate_name: data.name(),
+                });
             }
         }
 
diff --git a/compiler/rustc_metadata/src/dependency_format.rs b/compiler/rustc_metadata/src/dependency_format.rs
index b765c34f8e36..6112ec9e4e94 100644
--- a/compiler/rustc_metadata/src/dependency_format.rs
+++ b/compiler/rustc_metadata/src/dependency_format.rs
@@ -52,6 +52,10 @@
 //! than finding a number of solutions (there are normally quite a few).
 
 use crate::creader::CStore;
+use crate::errors::{
+    BadPanicStrategy, CrateDepMultiple, IncompatiblePanicInDropStrategy, LibRequired,
+    RequiredPanicStrategy, RlibRequired, TwoPanicRuntimes,
+};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::CrateNum;
@@ -136,11 +140,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
                 if src.rlib.is_some() {
                     continue;
                 }
-                sess.err(&format!(
-                    "crate `{}` required to be available in rlib format, \
-                                   but was not found in this form",
-                    tcx.crate_name(cnum)
-                ));
+                sess.emit_err(RlibRequired { crate_name: tcx.crate_name(cnum) });
             }
             return Vec::new();
         }
@@ -158,11 +158,11 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
         let name = tcx.crate_name(cnum);
         let src = tcx.used_crate_source(cnum);
         if src.dylib.is_some() {
-            tracing::info!("adding dylib: {}", name);
+            info!("adding dylib: {}", name);
             add_library(tcx, cnum, RequireDynamic, &mut formats);
             let deps = tcx.dylib_dependency_formats(cnum);
             for &(depnum, style) in deps.iter() {
-                tracing::info!("adding {:?}: {}", style, tcx.crate_name(depnum));
+                info!("adding {:?}: {}", style, tcx.crate_name(depnum));
                 add_library(tcx, depnum, style, &mut formats);
             }
         }
@@ -190,7 +190,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
             && tcx.dep_kind(cnum) == CrateDepKind::Explicit
         {
             assert!(src.rlib.is_some() || src.rmeta.is_some());
-            tracing::info!("adding staticlib: {}", tcx.crate_name(cnum));
+            info!("adding staticlib: {}", tcx.crate_name(cnum));
             add_library(tcx, cnum, RequireStatic, &mut formats);
             ret[cnum.as_usize() - 1] = Linkage::Static;
         }
@@ -224,12 +224,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
                     Linkage::Static => "rlib",
                     _ => "dylib",
                 };
-                sess.err(&format!(
-                    "crate `{}` required to be available in {} format, \
-                                   but was not found in this form",
-                    tcx.crate_name(cnum),
-                    kind
-                ));
+                sess.emit_err(LibRequired { crate_name: tcx.crate_name(cnum), kind: kind });
             }
         }
     }
@@ -253,17 +248,7 @@ fn add_library(
             // This error is probably a little obscure, but I imagine that it
             // can be refined over time.
             if link2 != link || link == RequireStatic {
-                tcx.sess
-                    .struct_err(&format!(
-                        "cannot satisfy dependencies so `{}` only \
-                                              shows up once",
-                        tcx.crate_name(cnum)
-                    ))
-                    .help(
-                        "having upstream crates all available in one format \
-                           will likely make this go away",
-                    )
-                    .emit();
+                tcx.sess.emit_err(CrateDepMultiple { crate_name: tcx.crate_name(cnum) });
             }
         }
         None => {
@@ -360,11 +345,7 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
             if let Some((prev, _)) = panic_runtime {
                 let prev_name = tcx.crate_name(prev);
                 let cur_name = tcx.crate_name(cnum);
-                sess.err(&format!(
-                    "cannot link together two \
-                                   panic runtimes: {} and {}",
-                    prev_name, cur_name
-                ));
+                sess.emit_err(TwoPanicRuntimes { prev_name, cur_name });
             }
             panic_runtime = Some((
                 cnum,
@@ -384,13 +365,10 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
         // First up, validate that our selected panic runtime is indeed exactly
         // our same strategy.
         if found_strategy != desired_strategy {
-            sess.err(&format!(
-                "the linked panic runtime `{}` is \
-                               not compiled with this crate's \
-                               panic strategy `{}`",
-                tcx.crate_name(runtime_cnum),
-                desired_strategy.desc()
-            ));
+            sess.emit_err(BadPanicStrategy {
+                runtime: tcx.crate_name(runtime_cnum),
+                strategy: desired_strategy,
+            });
         }
 
         // Next up, verify that all other crates are compatible with this panic
@@ -407,28 +385,19 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
             }
 
             if let Some(found_strategy) = tcx.required_panic_strategy(cnum) && desired_strategy != found_strategy {
-                sess.err(&format!(
-                    "the crate `{}` requires \
-                               panic strategy `{}` which is \
-                               incompatible with this crate's \
-                               strategy of `{}`",
-                    tcx.crate_name(cnum),
-                    found_strategy.desc(),
-                    desired_strategy.desc()
-                ));
+                sess.emit_err(RequiredPanicStrategy {
+                    crate_name: tcx.crate_name(cnum),
+                    found_strategy,
+                    desired_strategy});
             }
 
             let found_drop_strategy = tcx.panic_in_drop_strategy(cnum);
             if tcx.sess.opts.unstable_opts.panic_in_drop != found_drop_strategy {
-                sess.err(&format!(
-                    "the crate `{}` is compiled with the \
-                               panic-in-drop strategy `{}` which is \
-                               incompatible with this crate's \
-                               strategy of `{}`",
-                    tcx.crate_name(cnum),
-                    found_drop_strategy.desc(),
-                    tcx.sess.opts.unstable_opts.panic_in_drop.desc()
-                ));
+                sess.emit_err(IncompatiblePanicInDropStrategy {
+                    crate_name: tcx.crate_name(cnum),
+                    found_strategy: found_drop_strategy,
+                    desired_strategy: tcx.sess.opts.unstable_opts.panic_in_drop,
+                });
             }
         }
     }
diff --git a/compiler/rustc_metadata/src/errors.rs b/compiler/rustc_metadata/src/errors.rs
new file mode 100644
index 000000000000..1cd550644bf4
--- /dev/null
+++ b/compiler/rustc_metadata/src/errors.rs
@@ -0,0 +1,679 @@
+use std::{
+    io::Error,
+    path::{Path, PathBuf},
+};
+
+use rustc_errors::{error_code, ErrorGuaranteed, IntoDiagnostic};
+use rustc_macros::Diagnostic;
+use rustc_session::config;
+use rustc_span::{sym, Span, Symbol};
+use rustc_target::spec::{PanicStrategy, TargetTriple};
+
+use crate::locator::CrateFlavor;
+
+#[derive(Diagnostic)]
+#[diag(metadata::rlib_required)]
+pub struct RlibRequired {
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::lib_required)]
+pub struct LibRequired<'a> {
+    pub crate_name: Symbol,
+    pub kind: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::crate_dep_multiple)]
+#[help]
+pub struct CrateDepMultiple {
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::two_panic_runtimes)]
+pub struct TwoPanicRuntimes {
+    pub prev_name: Symbol,
+    pub cur_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::bad_panic_strategy)]
+pub struct BadPanicStrategy {
+    pub runtime: Symbol,
+    pub strategy: PanicStrategy,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::required_panic_strategy)]
+pub struct RequiredPanicStrategy {
+    pub crate_name: Symbol,
+    pub found_strategy: PanicStrategy,
+    pub desired_strategy: PanicStrategy,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::incompatible_panic_in_drop_strategy)]
+pub struct IncompatiblePanicInDropStrategy {
+    pub crate_name: Symbol,
+    pub found_strategy: PanicStrategy,
+    pub desired_strategy: PanicStrategy,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_names_in_link)]
+pub struct MultipleNamesInLink {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_kinds_in_link)]
+pub struct MultipleKindsInLink {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_name_form)]
+pub struct LinkNameForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_kind_form)]
+pub struct LinkKindForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_modifiers_form)]
+pub struct LinkModifiersForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_cfg_form)]
+pub struct LinkCfgForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::wasm_import_form)]
+pub struct WasmImportForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::empty_link_name, code = "E0454")]
+pub struct EmptyLinkName {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_framework_apple, code = "E0455")]
+pub struct LinkFrameworkApple {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::framework_only_windows, code = "E0455")]
+pub struct FrameworkOnlyWindows {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::unknown_link_kind, code = "E0458")]
+pub struct UnknownLinkKind<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub kind: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_link_modifiers)]
+pub struct MultipleLinkModifiers {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_cfgs)]
+pub struct MultipleCfgs {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_cfg_single_predicate)]
+pub struct LinkCfgSinglePredicate {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_wasm_import)]
+pub struct MultipleWasmImport {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::unexpected_link_arg)]
+pub struct UnexpectedLinkArg {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::invalid_link_modifier)]
+pub struct InvalidLinkModifier {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_modifiers)]
+pub struct MultipleModifiers<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub modifier: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::bundle_needs_static)]
+pub struct BundleNeedsStatic {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::whole_archive_needs_static)]
+pub struct WholeArchiveNeedsStatic {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::as_needed_compatibility)]
+pub struct AsNeededCompatibility {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::unknown_link_modifier)]
+pub struct UnknownLinkModifier<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub modifier: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::incompatible_wasm_link)]
+pub struct IncompatibleWasmLink {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_requires_name, code = "E0459")]
+pub struct LinkRequiresName {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::raw_dylib_no_nul)]
+pub struct RawDylibNoNul {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::link_ordinal_raw_dylib)]
+pub struct LinkOrdinalRawDylib {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::lib_framework_apple)]
+pub struct LibFrameworkApple;
+
+#[derive(Diagnostic)]
+#[diag(metadata::empty_renaming_target)]
+pub struct EmptyRenamingTarget<'a> {
+    pub lib_name: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::renaming_no_link)]
+pub struct RenamingNoLink<'a> {
+    pub lib_name: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_renamings)]
+pub struct MultipleRenamings<'a> {
+    pub lib_name: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::no_link_mod_override)]
+pub struct NoLinkModOverride {
+    #[primary_span]
+    pub span: Option<Span>,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::unsupported_abi_i686)]
+pub struct UnsupportedAbiI686 {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::unsupported_abi)]
+pub struct UnsupportedAbi {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::fail_create_file_encoder)]
+pub struct FailCreateFileEncoder {
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::fail_seek_file)]
+pub struct FailSeekFile {
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::fail_write_file)]
+pub struct FailWriteFile {
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::crate_not_panic_runtime)]
+pub struct CrateNotPanicRuntime {
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::no_panic_strategy)]
+pub struct NoPanicStrategy {
+    pub crate_name: Symbol,
+    pub strategy: PanicStrategy,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::profiler_builtins_needs_core)]
+pub struct ProfilerBuiltinsNeedsCore;
+
+#[derive(Diagnostic)]
+#[diag(metadata::not_profiler_runtime)]
+pub struct NotProfilerRuntime {
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::no_multiple_global_alloc)]
+pub struct NoMultipleGlobalAlloc {
+    #[primary_span]
+    #[label]
+    pub span2: Span,
+    #[label(metadata::prev_global_alloc)]
+    pub span1: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::conflicting_global_alloc)]
+pub struct ConflictingGlobalAlloc {
+    pub crate_name: Symbol,
+    pub other_crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::global_alloc_required)]
+pub struct GlobalAllocRequired;
+
+#[derive(Diagnostic)]
+#[diag(metadata::no_transitive_needs_dep)]
+pub struct NoTransitiveNeedsDep<'a> {
+    pub crate_name: Symbol,
+    pub needs_crate_name: &'a str,
+    pub deps_crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::failed_write_error)]
+pub struct FailedWriteError {
+    pub filename: PathBuf,
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::missing_native_library)]
+pub struct MissingNativeLibrary<'a> {
+    pub libname: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::failed_create_tempdir)]
+pub struct FailedCreateTempdir {
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::failed_create_file)]
+pub struct FailedCreateFile<'a> {
+    pub filename: &'a Path,
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::failed_create_encoded_metadata)]
+pub struct FailedCreateEncodedMetadata {
+    pub err: Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::non_ascii_name)]
+pub struct NonAsciiName {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::extern_location_not_exist)]
+pub struct ExternLocationNotExist<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub location: &'a Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::extern_location_not_file)]
+pub struct ExternLocationNotFile<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub location: &'a Path,
+}
+
+pub(crate) struct MultipleCandidates {
+    pub span: Span,
+    pub flavor: CrateFlavor,
+    pub crate_name: Symbol,
+    pub candidates: Vec<PathBuf>,
+}
+
+impl IntoDiagnostic<'_> for MultipleCandidates {
+    fn into_diagnostic(
+        self,
+        handler: &'_ rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(rustc_errors::fluent::metadata::multiple_candidates);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("flavor", self.flavor);
+        diag.code(error_code!(E0465));
+        diag.set_span(self.span);
+        for (i, candidate) in self.candidates.iter().enumerate() {
+            diag.span_note(self.span, &format!("candidate #{}: {}", i + 1, candidate.display()));
+        }
+        diag
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_matching_crates, code = "E0464")]
+#[note]
+pub struct MultipleMatchingCrates {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub candidates: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::symbol_conflicts_current, code = "E0519")]
+pub struct SymbolConflictsCurrent {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::symbol_conflicts_others, code = "E0523")]
+pub struct SymbolConflictsOthers {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::stable_crate_id_collision)]
+pub struct StableCrateIdCollision {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name0: Symbol,
+    pub crate_name1: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::dl_error)]
+pub struct DlError {
+    #[primary_span]
+    pub span: Span,
+    pub err: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::newer_crate_version, code = "E0460")]
+#[note]
+#[note(metadata::found_crate_versions)]
+pub struct NewerCrateVersion {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub found_crates: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::no_crate_with_triple, code = "E0461")]
+#[note(metadata::found_crate_versions)]
+pub struct NoCrateWithTriple<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub locator_triple: &'a str,
+    pub add_info: String,
+    pub found_crates: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::found_staticlib, code = "E0462")]
+#[note(metadata::found_crate_versions)]
+#[help]
+pub struct FoundStaticlib {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub found_crates: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::incompatible_rustc, code = "E0514")]
+#[note(metadata::found_crate_versions)]
+#[help]
+pub struct IncompatibleRustc {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub found_crates: String,
+    pub rustc_version: String,
+}
+
+pub struct InvalidMetadataFiles {
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub crate_rejections: Vec<String>,
+}
+
+impl IntoDiagnostic<'_> for InvalidMetadataFiles {
+    fn into_diagnostic(
+        self,
+        handler: &'_ rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(rustc_errors::fluent::metadata::invalid_meta_files);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("add_info", self.add_info);
+        diag.code(error_code!(E0786));
+        diag.set_span(self.span);
+        for crate_rejection in self.crate_rejections {
+            diag.note(crate_rejection);
+        }
+        diag
+    }
+}
+
+pub struct CannotFindCrate {
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub missing_core: bool,
+    pub current_crate: String,
+    pub is_nightly_build: bool,
+    pub profiler_runtime: Symbol,
+    pub locator_triple: TargetTriple,
+}
+
+impl IntoDiagnostic<'_> for CannotFindCrate {
+    fn into_diagnostic(
+        self,
+        handler: &'_ rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(rustc_errors::fluent::metadata::cannot_find_crate);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("current_crate", self.current_crate);
+        diag.set_arg("add_info", self.add_info);
+        diag.set_arg("locator_triple", self.locator_triple.triple());
+        diag.code(error_code!(E0463));
+        diag.set_span(self.span);
+        if (self.crate_name == sym::std || self.crate_name == sym::core)
+            && self.locator_triple != TargetTriple::from_triple(config::host_triple())
+        {
+            if self.missing_core {
+                diag.note(rustc_errors::fluent::metadata::target_not_installed);
+            } else {
+                diag.note(rustc_errors::fluent::metadata::target_no_std_support);
+            }
+            // NOTE: this suggests using rustup, even though the user may not have it installed.
+            // That's because they could choose to install it; or this may give them a hint which
+            // target they need to install from their distro.
+            if self.missing_core {
+                diag.help(rustc_errors::fluent::metadata::consider_downloading_target);
+            }
+            // Suggest using #![no_std]. #[no_core] is unstable and not really supported anyway.
+            // NOTE: this is a dummy span if `extern crate std` was injected by the compiler.
+            // If it's not a dummy, that means someone added `extern crate std` explicitly and
+            // `#![no_std]` won't help.
+            if !self.missing_core && self.span.is_dummy() {
+                diag.note(rustc_errors::fluent::metadata::std_required);
+            }
+            if self.is_nightly_build {
+                diag.help(rustc_errors::fluent::metadata::consider_building_std);
+            }
+        } else if self.crate_name == self.profiler_runtime {
+            diag.note(rustc_errors::fluent::metadata::compiler_missing_profiler);
+        } else if self.crate_name.as_str().starts_with("rustc_") {
+            diag.help(rustc_errors::fluent::metadata::install_missing_components);
+        }
+        diag.span_label(self.span, rustc_errors::fluent::metadata::cant_find_crate);
+        diag
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::no_dylib_plugin, code = "E0457")]
+pub struct NoDylibPlugin {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::crate_location_unknown_type)]
+pub struct CrateLocationUnknownType<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub path: &'a Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::lib_filename_form)]
+pub struct LibFilenameForm<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub dll_prefix: &'a str,
+    pub dll_suffix: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::multiple_import_name_type)]
+pub struct MultipleImportNameType {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::import_name_type_form)]
+pub struct ImportNameTypeForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::import_name_type_x86)]
+pub struct ImportNameTypeX86 {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::unknown_import_name_type)]
+pub struct UnknownImportNameType<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub import_name_type: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(metadata::import_name_type_raw)]
+pub struct ImportNameTypeRaw {
+    #[primary_span]
+    pub span: Span,
+}
diff --git a/compiler/rustc_metadata/src/fs.rs b/compiler/rustc_metadata/src/fs.rs
index e6072901aaa4..f360a586476e 100644
--- a/compiler/rustc_metadata/src/fs.rs
+++ b/compiler/rustc_metadata/src/fs.rs
@@ -1,3 +1,6 @@
+use crate::errors::{
+    FailedCreateEncodedMetadata, FailedCreateFile, FailedCreateTempdir, FailedWriteError,
+};
 use crate::{encode_metadata, EncodedMetadata};
 
 use rustc_data_structures::temp_dir::MaybeTempDir;
@@ -23,8 +26,8 @@ pub fn emit_metadata(sess: &Session, metadata: &[u8], tmpdir: &MaybeTempDir) ->
     let out_filename = tmpdir.as_ref().join(METADATA_FILENAME);
     let result = fs::write(&out_filename, metadata);
 
-    if let Err(e) = result {
-        sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
+    if let Err(err) = result {
+        sess.emit_fatal(FailedWriteError { filename: out_filename, err });
     }
 
     out_filename
@@ -65,7 +68,7 @@ pub fn encode_and_write_metadata(
     let metadata_tmpdir = TempFileBuilder::new()
         .prefix("rmeta")
         .tempdir_in(out_filename.parent().unwrap_or_else(|| Path::new("")))
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("couldn't create a temp dir: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailedCreateTempdir { err }));
     let metadata_tmpdir = MaybeTempDir::new(metadata_tmpdir, tcx.sess.opts.cg.save_temps);
     let metadata_filename = metadata_tmpdir.as_ref().join(METADATA_FILENAME);
 
@@ -73,12 +76,8 @@ pub fn encode_and_write_metadata(
     // This simplifies the creation of the output `out_filename` when requested.
     match metadata_kind {
         MetadataKind::None => {
-            std::fs::File::create(&metadata_filename).unwrap_or_else(|e| {
-                tcx.sess.fatal(&format!(
-                    "failed to create the file {}: {}",
-                    metadata_filename.display(),
-                    e
-                ))
+            std::fs::File::create(&metadata_filename).unwrap_or_else(|err| {
+                tcx.sess.emit_fatal(FailedCreateFile { filename: &metadata_filename, err });
             });
         }
         MetadataKind::Uncompressed | MetadataKind::Compressed => {
@@ -93,8 +92,8 @@ pub fn encode_and_write_metadata(
     // this file always exists.
     let need_metadata_file = tcx.sess.opts.output_types.contains_key(&OutputType::Metadata);
     let (metadata_filename, metadata_tmpdir) = if need_metadata_file {
-        if let Err(e) = non_durable_rename(&metadata_filename, &out_filename) {
-            tcx.sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
+        if let Err(err) = non_durable_rename(&metadata_filename, &out_filename) {
+            tcx.sess.emit_fatal(FailedWriteError { filename: out_filename, err });
         }
         if tcx.sess.opts.json_artifact_notifications {
             tcx.sess
@@ -109,8 +108,8 @@ pub fn encode_and_write_metadata(
 
     // Load metadata back to memory: codegen may need to include it in object files.
     let metadata =
-        EncodedMetadata::from_path(metadata_filename, metadata_tmpdir).unwrap_or_else(|e| {
-            tcx.sess.fatal(&format!("failed to create encoded metadata from file: {}", e))
+        EncodedMetadata::from_path(metadata_filename, metadata_tmpdir).unwrap_or_else(|err| {
+            tcx.sess.emit_fatal(FailedCreateEncodedMetadata { err });
         });
 
     let need_metadata_module = metadata_kind == MetadataKind::Compressed;
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index 6440f3e390cf..98cf6fef54a8 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -2,10 +2,8 @@
 #![feature(decl_macro)]
 #![feature(drain_filter)]
 #![feature(generators)]
-#![feature(generic_associated_types)]
 #![feature(iter_from_generator)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(once_cell)]
 #![feature(proc_macro_internals)]
 #![feature(macro_metavar_expr)]
@@ -16,6 +14,8 @@
 #![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 extern crate proc_macro;
 
@@ -26,6 +26,9 @@ extern crate rustc_middle;
 #[macro_use]
 extern crate rustc_data_structures;
 
+#[macro_use]
+extern crate tracing;
+
 pub use rmeta::{provide, provide_extern};
 
 mod dependency_format;
@@ -34,8 +37,10 @@ mod native_libs;
 mod rmeta;
 
 pub mod creader;
+pub mod errors;
 pub mod fs;
 pub mod locator;
 
 pub use fs::{emit_metadata, METADATA_FILENAME};
+pub use native_libs::find_native_static_library;
 pub use rmeta::{encode_metadata, EncodedMetadata, METADATA_HEADER};
diff --git a/compiler/rustc_metadata/src/locator.rs b/compiler/rustc_metadata/src/locator.rs
index 2c1c84b0be26..35f9ef92a1c4 100644
--- a/compiler/rustc_metadata/src/locator.rs
+++ b/compiler/rustc_metadata/src/locator.rs
@@ -213,6 +213,13 @@
 //! metadata::locator or metadata::creader for all the juicy details!
 
 use crate::creader::Library;
+use crate::errors::{
+    CannotFindCrate, CrateLocationUnknownType, DlError, ExternLocationNotExist,
+    ExternLocationNotFile, FoundStaticlib, IncompatibleRustc, InvalidMetadataFiles,
+    LibFilenameForm, MultipleCandidates, MultipleMatchingCrates, NewerCrateVersion,
+    NoCrateWithTriple, NoDylibPlugin, NonAsciiName, StableCrateIdCollision, SymbolConflictsCurrent,
+    SymbolConflictsOthers,
+};
 use crate::rmeta::{rustc_version, MetadataBlob, METADATA_HEADER};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -220,23 +227,23 @@ use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::owning_ref::OwningRef;
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::MetadataRef;
-use rustc_errors::{struct_span_err, FatalError};
+use rustc_errors::{DiagnosticArgValue, FatalError, IntoDiagnosticArg};
 use rustc_session::config::{self, CrateType};
 use rustc_session::cstore::{CrateSource, MetadataLoader};
 use rustc_session::filesearch::FileSearch;
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::CanonicalizedPath;
 use rustc_session::Session;
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_target::spec::{Target, TargetTriple};
 
 use snap::read::FrameDecoder;
+use std::borrow::Cow;
 use std::fmt::Write as _;
 use std::io::{Read, Result as IoResult, Write};
 use std::path::{Path, PathBuf};
 use std::{cmp, fmt, fs};
-use tracing::{debug, info};
 
 #[derive(Clone)]
 pub(crate) struct CrateLocator<'a> {
@@ -288,6 +295,16 @@ impl fmt::Display for CrateFlavor {
     }
 }
 
+impl IntoDiagnosticArg for CrateFlavor {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        match self {
+            CrateFlavor::Rlib => DiagnosticArgValue::Str(Cow::Borrowed("rlib")),
+            CrateFlavor::Rmeta => DiagnosticArgValue::Str(Cow::Borrowed("rmeta")),
+            CrateFlavor::Dylib => DiagnosticArgValue::Str(Cow::Borrowed("dylib")),
+        }
+    }
+}
+
 impl<'a> CrateLocator<'a> {
     pub(crate) fn new(
         sess: &'a Session,
@@ -938,41 +955,20 @@ impl fmt::Display for MetadataError<'_> {
 
 impl CrateError {
     pub(crate) fn report(self, sess: &Session, span: Span, missing_core: bool) {
-        let mut diag = match self {
-            CrateError::NonAsciiName(crate_name) => sess.struct_span_err(
-                span,
-                &format!("cannot load a crate with a non-ascii name `{}`", crate_name),
-            ),
-            CrateError::ExternLocationNotExist(crate_name, loc) => sess.struct_span_err(
-                span,
-                &format!("extern location for {} does not exist: {}", crate_name, loc.display()),
-            ),
-            CrateError::ExternLocationNotFile(crate_name, loc) => sess.struct_span_err(
-                span,
-                &format!("extern location for {} is not a file: {}", crate_name, loc.display()),
-            ),
+        match self {
+            CrateError::NonAsciiName(crate_name) => {
+                sess.emit_err(NonAsciiName { span, crate_name });
+            }
+            CrateError::ExternLocationNotExist(crate_name, loc) => {
+                sess.emit_err(ExternLocationNotExist { span, crate_name, location: &loc });
+            }
+            CrateError::ExternLocationNotFile(crate_name, loc) => {
+                sess.emit_err(ExternLocationNotFile { span, crate_name, location: &loc });
+            }
             CrateError::MultipleCandidates(crate_name, flavor, candidates) => {
-                let mut err = struct_span_err!(
-                    sess,
-                    span,
-                    E0465,
-                    "multiple {} candidates for `{}` found",
-                    flavor,
-                    crate_name,
-                );
-                for (i, candidate) in candidates.iter().enumerate() {
-                    err.span_note(span, &format!("candidate #{}: {}", i + 1, candidate.display()));
-                }
-                err
+                sess.emit_err(MultipleCandidates { span, flavor: flavor, crate_name, candidates });
             }
             CrateError::MultipleMatchingCrates(crate_name, libraries) => {
-                let mut err = struct_span_err!(
-                    sess,
-                    span,
-                    E0464,
-                    "multiple matching crates for `{}`",
-                    crate_name
-                );
                 let mut libraries: Vec<_> = libraries.into_values().collect();
                 // Make ordering of candidates deterministic.
                 // This has to `clone()` to work around lifetime restrictions with `sort_by_key()`.
@@ -1000,223 +996,142 @@ impl CrateError {
                         s
                     })
                     .collect::<String>();
-                err.note(&format!("candidates:{}", candidates));
-                err
+                sess.emit_err(MultipleMatchingCrates { span, crate_name, candidates });
+            }
+            CrateError::SymbolConflictsCurrent(root_name) => {
+                sess.emit_err(SymbolConflictsCurrent { span, crate_name: root_name });
+            }
+            CrateError::SymbolConflictsOthers(root_name) => {
+                sess.emit_err(SymbolConflictsOthers { span, crate_name: root_name });
             }
-            CrateError::SymbolConflictsCurrent(root_name) => struct_span_err!(
-                sess,
-                span,
-                E0519,
-                "the current crate is indistinguishable from one of its dependencies: it has the \
-                 same crate-name `{}` and was compiled with the same `-C metadata` arguments. \
-                 This will result in symbol conflicts between the two.",
-                root_name,
-            ),
-            CrateError::SymbolConflictsOthers(root_name) => struct_span_err!(
-                sess,
-                span,
-                E0523,
-                "found two different crates with name `{}` that are not distinguished by differing \
-                 `-C metadata`. This will result in symbol conflicts between the two.",
-                root_name,
-            ),
             CrateError::StableCrateIdCollision(crate_name0, crate_name1) => {
-                let msg = format!(
-                    "found crates (`{}` and `{}`) with colliding StableCrateId values.",
-                    crate_name0, crate_name1
-                );
-                sess.struct_span_err(span, &msg)
+                sess.emit_err(StableCrateIdCollision {
+                    span,
+                    crate_name0: crate_name0,
+                    crate_name1: crate_name1,
+                });
+            }
+            CrateError::DlOpen(s) | CrateError::DlSym(s) => {
+                sess.emit_err(DlError { span, err: s });
             }
-            CrateError::DlOpen(s) | CrateError::DlSym(s) => sess.struct_span_err(span, &s),
             CrateError::LocatorCombined(locator) => {
                 let crate_name = locator.crate_name;
-                let add = match &locator.root {
+                let add_info = match &locator.root {
                     None => String::new(),
                     Some(r) => format!(" which `{}` depends on", r.name),
                 };
-                let mut msg = "the following crate versions were found:".to_string();
-                let mut err = if !locator.crate_rejections.via_hash.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
-                        span,
-                        E0460,
-                        "found possibly newer version of crate `{}`{}",
-                        crate_name,
-                        add,
-                    );
-                    err.note("perhaps that crate needs to be recompiled?");
+                // FIXME: There are no tests for CrateLocationUnknownType or LibFilenameForm
+                if !locator.crate_rejections.via_filename.is_empty() {
+                    let mismatches = locator.crate_rejections.via_filename.iter();
+                    for CrateMismatch { path, .. } in mismatches {
+                        sess.emit_err(CrateLocationUnknownType { span, path: &path });
+                        sess.emit_err(LibFilenameForm {
+                            span,
+                            dll_prefix: &locator.dll_prefix,
+                            dll_suffix: &locator.dll_suffix,
+                        });
+                    }
+                }
+                let mut found_crates = String::new();
+                if !locator.crate_rejections.via_hash.is_empty() {
                     let mismatches = locator.crate_rejections.via_hash.iter();
                     for CrateMismatch { path, .. } in mismatches {
-                        msg.push_str(&format!("\ncrate `{}`: {}", crate_name, path.display()));
+                        found_crates.push_str(&format!(
+                            "\ncrate `{}`: {}",
+                            crate_name,
+                            path.display()
+                        ));
                     }
                     if let Some(r) = locator.root {
                         for path in r.source.paths() {
-                            msg.push_str(&format!("\ncrate `{}`: {}", r.name, path.display()));
+                            found_crates.push_str(&format!(
+                                "\ncrate `{}`: {}",
+                                r.name,
+                                path.display()
+                            ));
                         }
                     }
-                    err.note(&msg);
-                    err
-                } else if !locator.crate_rejections.via_triple.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(NewerCrateVersion {
                         span,
-                        E0461,
-                        "couldn't find crate `{}` with expected target triple {}{}",
-                        crate_name,
-                        locator.triple,
-                        add,
-                    );
+                        crate_name: crate_name,
+                        add_info,
+                        found_crates,
+                    });
+                } else if !locator.crate_rejections.via_triple.is_empty() {
                     let mismatches = locator.crate_rejections.via_triple.iter();
                     for CrateMismatch { path, got } in mismatches {
-                        msg.push_str(&format!(
+                        found_crates.push_str(&format!(
                             "\ncrate `{}`, target triple {}: {}",
                             crate_name,
                             got,
                             path.display(),
                         ));
                     }
-                    err.note(&msg);
-                    err
-                } else if !locator.crate_rejections.via_kind.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(NoCrateWithTriple {
                         span,
-                        E0462,
-                        "found staticlib `{}` instead of rlib or dylib{}",
-                        crate_name,
-                        add,
-                    );
-                    err.help("please recompile that crate using --crate-type lib");
+                        crate_name: crate_name,
+                        locator_triple: locator.triple.triple(),
+                        add_info,
+                        found_crates,
+                    });
+                } else if !locator.crate_rejections.via_kind.is_empty() {
                     let mismatches = locator.crate_rejections.via_kind.iter();
                     for CrateMismatch { path, .. } in mismatches {
-                        msg.push_str(&format!("\ncrate `{}`: {}", crate_name, path.display()));
+                        found_crates.push_str(&format!(
+                            "\ncrate `{}`: {}",
+                            crate_name,
+                            path.display()
+                        ));
                     }
-                    err.note(&msg);
-                    err
+                    sess.emit_err(FoundStaticlib { span, crate_name, add_info, found_crates });
                 } else if !locator.crate_rejections.via_version.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
-                        span,
-                        E0514,
-                        "found crate `{}` compiled by an incompatible version of rustc{}",
-                        crate_name,
-                        add,
-                    );
-                    err.help(&format!(
-                        "please recompile that crate using this compiler ({}) \
-                         (consider running `cargo clean` first)",
-                        rustc_version(),
-                    ));
                     let mismatches = locator.crate_rejections.via_version.iter();
                     for CrateMismatch { path, got } in mismatches {
-                        msg.push_str(&format!(
+                        found_crates.push_str(&format!(
                             "\ncrate `{}` compiled by {}: {}",
                             crate_name,
                             got,
                             path.display(),
                         ));
                     }
-                    err.note(&msg);
-                    err
+                    sess.emit_err(IncompatibleRustc {
+                        span,
+                        crate_name,
+                        add_info,
+                        found_crates,
+                        rustc_version: rustc_version(),
+                    });
                 } else if !locator.crate_rejections.via_invalid.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
-                        span,
-                        E0786,
-                        "found invalid metadata files for crate `{}`{}",
-                        crate_name,
-                        add,
-                    );
+                    let mut crate_rejections = Vec::new();
                     for CrateMismatch { path: _, got } in locator.crate_rejections.via_invalid {
-                        err.note(&got);
+                        crate_rejections.push(got);
                     }
-                    err
-                } else {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(InvalidMetadataFiles {
                         span,
-                        E0463,
-                        "can't find crate for `{}`{}",
                         crate_name,
-                        add,
-                    );
-
-                    if (crate_name == sym::std || crate_name == sym::core)
-                        && locator.triple != TargetTriple::from_triple(config::host_triple())
-                    {
-                        if missing_core {
-                            err.note(&format!(
-                                "the `{}` target may not be installed",
-                                locator.triple
-                            ));
-                        } else {
-                            err.note(&format!(
-                                "the `{}` target may not support the standard library",
-                                locator.triple
-                            ));
-                        }
-                        // NOTE: this suggests using rustup, even though the user may not have it installed.
-                        // That's because they could choose to install it; or this may give them a hint which
-                        // target they need to install from their distro.
-                        if missing_core {
-                            err.help(&format!(
-                                "consider downloading the target with `rustup target add {}`",
-                                locator.triple
-                            ));
-                        }
-                        // Suggest using #![no_std]. #[no_core] is unstable and not really supported anyway.
-                        // NOTE: this is a dummy span if `extern crate std` was injected by the compiler.
-                        // If it's not a dummy, that means someone added `extern crate std` explicitly and `#![no_std]` won't help.
-                        if !missing_core && span.is_dummy() {
-                            let current_crate =
-                                sess.opts.crate_name.as_deref().unwrap_or("<unknown>");
-                            err.note(&format!(
-                                "`std` is required by `{}` because it does not declare `#![no_std]`",
-                                current_crate
-                            ));
-                        }
-                        if sess.is_nightly_build() {
-                            err.help("consider building the standard library from source with `cargo build -Zbuild-std`");
-                        }
-                    } else if crate_name
-                        == Symbol::intern(&sess.opts.unstable_opts.profiler_runtime)
-                    {
-                        err.note("the compiler may have been built without the profiler runtime");
-                    } else if crate_name.as_str().starts_with("rustc_") {
-                        err.help(
-                            "maybe you need to install the missing components with: \
-                             `rustup component add rust-src rustc-dev llvm-tools-preview`",
-                        );
-                    }
-                    err.span_label(span, "can't find crate");
-                    err
-                };
-
-                if !locator.crate_rejections.via_filename.is_empty() {
-                    let mismatches = locator.crate_rejections.via_filename.iter();
-                    for CrateMismatch { path, .. } in mismatches {
-                        err.note(&format!(
-                            "extern location for {} is of an unknown type: {}",
-                            crate_name,
-                            path.display(),
-                        ))
-                        .help(&format!(
-                            "file name should be lib*.rlib or {}*.{}",
-                            locator.dll_prefix, locator.dll_suffix
-                        ));
-                    }
+                        add_info,
+                        crate_rejections,
+                    });
+                } else {
+                    sess.emit_err(CannotFindCrate {
+                        span,
+                        crate_name,
+                        add_info,
+                        missing_core,
+                        current_crate: sess
+                            .opts
+                            .crate_name
+                            .clone()
+                            .unwrap_or("<unknown>".to_string()),
+                        is_nightly_build: sess.is_nightly_build(),
+                        profiler_runtime: Symbol::intern(&sess.opts.unstable_opts.profiler_runtime),
+                        locator_triple: locator.triple,
+                    });
                 }
-                err
             }
-            CrateError::NonDylibPlugin(crate_name) => struct_span_err!(
-                sess,
-                span,
-                E0457,
-                "plugin `{}` only found in rlib format, but must be available in dylib format",
-                crate_name,
-            ),
-        };
-
-        diag.emit();
+            CrateError::NonDylibPlugin(crate_name) => {
+                sess.emit_err(NoDylibPlugin { span, crate_name });
+            }
+        }
     }
 }
diff --git a/compiler/rustc_metadata/src/native_libs.rs b/compiler/rustc_metadata/src/native_libs.rs
index 8bafe203748f..9abb5c74895d 100644
--- a/compiler/rustc_metadata/src/native_libs.rs
+++ b/compiler/rustc_metadata/src/native_libs.rs
@@ -1,17 +1,80 @@
 use rustc_ast::{NestedMetaItem, CRATE_NODE_ID};
 use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_middle::ty::{List, ParamEnv, ParamEnvAnd, Ty, TyCtxt};
+use rustc_session::config::CrateType;
 use rustc_session::cstore::{DllCallingConvention, DllImport, NativeLib, PeImportNameType};
 use rustc_session::parse::feature_err;
+use rustc_session::search_paths::PathKind;
 use rustc_session::utils::NativeLibKind;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_target::spec::abi::Abi;
 
+use crate::errors::{
+    AsNeededCompatibility, BundleNeedsStatic, EmptyLinkName, EmptyRenamingTarget,
+    FrameworkOnlyWindows, ImportNameTypeForm, ImportNameTypeRaw, ImportNameTypeX86,
+    IncompatibleWasmLink, InvalidLinkModifier, LibFrameworkApple, LinkCfgForm,
+    LinkCfgSinglePredicate, LinkFrameworkApple, LinkKindForm, LinkModifiersForm, LinkNameForm,
+    LinkOrdinalRawDylib, LinkRequiresName, MissingNativeLibrary, MultipleCfgs,
+    MultipleImportNameType, MultipleKindsInLink, MultipleLinkModifiers, MultipleModifiers,
+    MultipleNamesInLink, MultipleRenamings, MultipleWasmImport, NoLinkModOverride, RawDylibNoNul,
+    RenamingNoLink, UnexpectedLinkArg, UnknownImportNameType, UnknownLinkKind, UnknownLinkModifier,
+    UnsupportedAbi, UnsupportedAbiI686, WasmImportForm, WholeArchiveNeedsStatic,
+};
+
+use std::path::PathBuf;
+
+pub fn find_native_static_library(
+    name: &str,
+    verbatim: Option<bool>,
+    search_paths: &[PathBuf],
+    sess: &Session,
+) -> PathBuf {
+    let formats = if verbatim.unwrap_or(false) {
+        vec![("".into(), "".into())]
+    } else {
+        let os = (sess.target.staticlib_prefix.clone(), sess.target.staticlib_suffix.clone());
+        // On Windows, static libraries sometimes show up as libfoo.a and other
+        // times show up as foo.lib
+        let unix = ("lib".into(), ".a".into());
+        if os == unix { vec![os] } else { vec![os, unix] }
+    };
+
+    for path in search_paths {
+        for (prefix, suffix) in &formats {
+            let test = path.join(format!("{}{}{}", prefix, name, suffix));
+            if test.exists() {
+                return test;
+            }
+        }
+    }
+
+    sess.emit_fatal(MissingNativeLibrary { libname: name });
+}
+
+fn find_bundled_library(
+    name: Option<Symbol>,
+    verbatim: Option<bool>,
+    kind: NativeLibKind,
+    sess: &Session,
+) -> Option<Symbol> {
+    if sess.opts.unstable_opts.packed_bundled_libs &&
+            sess.crate_types().iter().any(|ct| ct == &CrateType::Rlib || ct == &CrateType::Staticlib) &&
+            let NativeLibKind::Static { bundle: Some(true) | None, .. } = kind {
+        find_native_static_library(
+            name.unwrap().as_str(),
+            verbatim,
+            &sess.target_filesearch(PathKind::Native).search_path_dirs(),
+            sess,
+        ).file_name().and_then(|s| s.to_str()).map(Symbol::intern)
+    } else {
+        None
+    }
+}
+
 pub(crate) fn collect(tcx: TyCtxt<'_>) -> Vec<NativeLib> {
     let mut collector = Collector { tcx, libs: Vec::new() };
     for id in tcx.hir().items() {
@@ -66,32 +129,26 @@ impl<'tcx> Collector<'tcx> {
                 match item.name_or_empty() {
                     sym::name => {
                         if name.is_some() {
-                            let msg = "multiple `name` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleNamesInLink { span: item.span() });
                             continue;
                         }
                         let Some(link_name) = item.value_str() else {
-                            let msg = "link name must be of the form `name = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkNameForm { span: item.span() });
                             continue;
                         };
                         let span = item.name_value_literal_span().unwrap();
                         if link_name.is_empty() {
-                            struct_span_err!(sess, span, E0454, "link name must not be empty")
-                                .span_label(span, "empty link name")
-                                .emit();
+                            sess.emit_err(EmptyLinkName { span });
                         }
                         name = Some((link_name, span));
                     }
                     sym::kind => {
                         if kind.is_some() {
-                            let msg = "multiple `kind` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleKindsInLink { span: item.span() });
                             continue;
                         }
                         let Some(link_kind) = item.value_str() else {
-                            let msg = "link kind must be of the form `kind = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkKindForm { span: item.span() });
                             continue;
                         };
 
@@ -101,44 +158,26 @@ impl<'tcx> Collector<'tcx> {
                             "dylib" => NativeLibKind::Dylib { as_needed: None },
                             "framework" => {
                                 if !sess.target.is_like_osx {
-                                    struct_span_err!(
-                                        sess,
-                                        span,
-                                        E0455,
-                                        "link kind `framework` is only supported on Apple targets"
-                                    )
-                                    .emit();
+                                    sess.emit_err(LinkFrameworkApple { span });
                                 }
                                 NativeLibKind::Framework { as_needed: None }
                             }
                             "raw-dylib" => {
                                 if !sess.target.is_like_windows {
-                                    struct_span_err!(
-                                        sess,
-                                        span,
-                                        E0455,
-                                        "link kind `raw-dylib` is only supported on Windows targets"
-                                    )
-                                    .emit();
-                                } else if !features.raw_dylib {
+                                    sess.emit_err(FrameworkOnlyWindows { span });
+                                } else if !features.raw_dylib && sess.target.arch == "x86" {
                                     feature_err(
                                         &sess.parse_sess,
                                         sym::raw_dylib,
                                         span,
-                                        "link kind `raw-dylib` is unstable",
+                                        "link kind `raw-dylib` is unstable on x86",
                                     )
                                     .emit();
                                 }
                                 NativeLibKind::RawDylib
                             }
                             kind => {
-                                let msg = format!(
-                                    "unknown link kind `{kind}`, expected one of: \
-                                     static, dylib, framework, raw-dylib"
-                                );
-                                struct_span_err!(sess, span, E0458, "{}", msg)
-                                    .span_label(span, "unknown link kind")
-                                    .emit();
+                                sess.emit_err(UnknownLinkKind { span, kind });
                                 continue;
                             }
                         };
@@ -146,32 +185,26 @@ impl<'tcx> Collector<'tcx> {
                     }
                     sym::modifiers => {
                         if modifiers.is_some() {
-                            let msg =
-                                "multiple `modifiers` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleLinkModifiers { span: item.span() });
                             continue;
                         }
                         let Some(link_modifiers) = item.value_str() else {
-                            let msg = "link modifiers must be of the form `modifiers = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkModifiersForm { span: item.span() });
                             continue;
                         };
                         modifiers = Some((link_modifiers, item.name_value_literal_span().unwrap()));
                     }
                     sym::cfg => {
                         if cfg.is_some() {
-                            let msg = "multiple `cfg` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleCfgs { span: item.span() });
                             continue;
                         }
                         let Some(link_cfg) = item.meta_item_list() else {
-                            let msg = "link cfg must be of the form `cfg(/* predicate */)`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkCfgForm { span: item.span() });
                             continue;
                         };
                         let [NestedMetaItem::MetaItem(link_cfg)] = link_cfg else {
-                            let msg = "link cfg must have a single predicate argument";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkCfgSinglePredicate { span: item.span() });
                             continue;
                         };
                         if !features.link_cfg {
@@ -187,33 +220,26 @@ impl<'tcx> Collector<'tcx> {
                     }
                     sym::wasm_import_module => {
                         if wasm_import_module.is_some() {
-                            let msg = "multiple `wasm_import_module` arguments \
-                                       in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleWasmImport { span: item.span() });
                             continue;
                         }
                         let Some(link_wasm_import_module) = item.value_str() else {
-                            let msg = "wasm import module must be of the form \
-                                       `wasm_import_module = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(WasmImportForm { span: item.span() });
                             continue;
                         };
                         wasm_import_module = Some((link_wasm_import_module, item.span()));
                     }
                     sym::import_name_type => {
                         if import_name_type.is_some() {
-                            let msg = "multiple `import_name_type` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleImportNameType { span: item.span() });
                             continue;
                         }
                         let Some(link_import_name_type) = item.value_str() else {
-                            let msg = "import name type must be of the form `import_name_type = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(ImportNameTypeForm { span: item.span() });
                             continue;
                         };
                         if self.tcx.sess.target.arch != "x86" {
-                            let msg = "import name type is only supported on x86";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(ImportNameTypeX86 { span: item.span() });
                             continue;
                         }
 
@@ -222,11 +248,10 @@ impl<'tcx> Collector<'tcx> {
                             "noprefix" => PeImportNameType::NoPrefix,
                             "undecorated" => PeImportNameType::Undecorated,
                             import_name_type => {
-                                let msg = format!(
-                                    "unknown import name type `{import_name_type}`, expected one of: \
-                                     decorated, noprefix, undecorated"
-                                );
-                                sess.span_err(item.span(), msg);
+                                sess.emit_err(UnknownImportNameType {
+                                    span: item.span(),
+                                    import_name_type,
+                                });
                                 continue;
                             }
                         };
@@ -243,9 +268,7 @@ impl<'tcx> Collector<'tcx> {
                         import_name_type = Some((link_import_name_type, item.span()));
                     }
                     _ => {
-                        let msg = "unexpected `#[link]` argument, expected one of: \
-                                   name, kind, modifiers, cfg, wasm_import_module, import_name_type";
-                        sess.span_err(item.span(), msg);
+                        sess.emit_err(UnexpectedLinkArg { span: item.span() });
                     }
                 }
             }
@@ -257,11 +280,7 @@ impl<'tcx> Collector<'tcx> {
                     let (modifier, value) = match modifier.strip_prefix(&['+', '-']) {
                         Some(m) => (m, modifier.starts_with('+')),
                         None => {
-                            sess.span_err(
-                                span,
-                                "invalid linking modifier syntax, expected '+' or '-' prefix \
-                                before one of: bundle, verbatim, whole-archive, as-needed",
-                            );
+                            sess.emit_err(InvalidLinkModifier { span });
                             continue;
                         }
                     };
@@ -279,10 +298,7 @@ impl<'tcx> Collector<'tcx> {
                     }
                     let assign_modifier = |dst: &mut Option<bool>| {
                         if dst.is_some() {
-                            let msg = format!(
-                                "multiple `{modifier}` modifiers in a single `modifiers` argument"
-                            );
-                            sess.span_err(span, &msg);
+                            sess.emit_err(MultipleModifiers { span, modifier });
                         } else {
                             *dst = Some(value);
                         }
@@ -292,11 +308,7 @@ impl<'tcx> Collector<'tcx> {
                             assign_modifier(bundle)
                         }
                         ("bundle", _) => {
-                            sess.span_err(
-                                span,
-                                "linking modifier `bundle` is only compatible with \
-                                 `static` linking kind",
-                            );
+                            sess.emit_err(BundleNeedsStatic { span });
                         }
 
                         ("verbatim", _) => {
@@ -308,11 +320,7 @@ impl<'tcx> Collector<'tcx> {
                             assign_modifier(whole_archive)
                         }
                         ("whole-archive", _) => {
-                            sess.span_err(
-                                span,
-                                "linking modifier `whole-archive` is only compatible with \
-                                 `static` linking kind",
-                            );
+                            sess.emit_err(WholeArchiveNeedsStatic { span });
                         }
 
                         ("as-needed", Some(NativeLibKind::Dylib { as_needed }))
@@ -321,21 +329,11 @@ impl<'tcx> Collector<'tcx> {
                             assign_modifier(as_needed)
                         }
                         ("as-needed", _) => {
-                            sess.span_err(
-                                span,
-                                "linking modifier `as-needed` is only compatible with \
-                                 `dylib` and `framework` linking kinds",
-                            );
+                            sess.emit_err(AsNeededCompatibility { span });
                         }
 
                         _ => {
-                            sess.span_err(
-                                span,
-                                format!(
-                                    "unknown linking modifier `{modifier}`, expected one of: \
-                                     bundle, verbatim, whole-archive, as-needed"
-                                ),
-                            );
+                            sess.emit_err(UnknownLinkModifier { span, modifier });
                         }
                     }
                 }
@@ -343,36 +341,23 @@ impl<'tcx> Collector<'tcx> {
 
             if let Some((_, span)) = wasm_import_module {
                 if name.is_some() || kind.is_some() || modifiers.is_some() || cfg.is_some() {
-                    let msg = "`wasm_import_module` is incompatible with \
-                               other arguments in `#[link]` attributes";
-                    sess.span_err(span, msg);
+                    sess.emit_err(IncompatibleWasmLink { span });
                 }
             } else if name.is_none() {
-                struct_span_err!(
-                    sess,
-                    m.span,
-                    E0459,
-                    "`#[link]` attribute requires a `name = \"string\"` argument"
-                )
-                .span_label(m.span, "missing `name` argument")
-                .emit();
+                sess.emit_err(LinkRequiresName { span: m.span });
             }
 
             // Do this outside of the loop so that `import_name_type` can be specified before `kind`.
             if let Some((_, span)) = import_name_type {
                 if kind != Some(NativeLibKind::RawDylib) {
-                    let msg = "import name type can only be used with link kind `raw-dylib`";
-                    sess.span_err(span, msg);
+                    sess.emit_err(ImportNameTypeRaw { span });
                 }
             }
 
             let dll_imports = match kind {
                 Some(NativeLibKind::RawDylib) => {
                     if let Some((name, span)) = name && name.as_str().contains('\0') {
-                        sess.span_err(
-                            span,
-                            "link name must not contain NUL characters if link kind is `raw-dylib`",
-                        );
+                        sess.emit_err(RawDylibNoNul { span });
                     }
                     foreign_mod_items
                         .iter()
@@ -397,23 +382,25 @@ impl<'tcx> Collector<'tcx> {
                             let link_ordinal_attr = self
                                 .tcx
                                 .hir()
-                                .attrs(self.tcx.hir().local_def_id_to_hir_id(child_item.id.def_id))
+                                .attrs(child_item.id.def_id.into())
                                 .iter()
                                 .find(|a| a.has_name(sym::link_ordinal))
                                 .unwrap();
-                            sess.span_err(
-                                link_ordinal_attr.span,
-                                "`#[link_ordinal]` is only supported if link kind is `raw-dylib`",
-                            );
+                            sess.emit_err(LinkOrdinalRawDylib { span: link_ordinal_attr.span });
                         }
                     }
 
                     Vec::new()
                 }
             };
+
+            let name = name.map(|(name, _)| name);
+            let kind = kind.unwrap_or(NativeLibKind::Unspecified);
+            let filename = find_bundled_library(name, verbatim, kind, sess);
             self.libs.push(NativeLib {
-                name: name.map(|(name, _)| name),
-                kind: kind.unwrap_or(NativeLibKind::Unspecified),
+                name,
+                filename,
+                kind,
                 cfg,
                 foreign_module: Some(it.def_id.to_def_id()),
                 wasm_import_module: wasm_import_module.map(|(name, _)| name),
@@ -430,7 +417,7 @@ impl<'tcx> Collector<'tcx> {
         for lib in &self.tcx.sess.opts.libs {
             if let NativeLibKind::Framework { .. } = lib.kind && !self.tcx.sess.target.is_like_osx {
                 // Cannot check this when parsing options because the target is not yet available.
-                self.tcx.sess.err("library kind `framework` is only supported on Apple targets");
+                self.tcx.sess.emit_err(LibFrameworkApple);
             }
             if let Some(ref new_name) = lib.new_name {
                 let any_duplicate = self
@@ -439,23 +426,11 @@ impl<'tcx> Collector<'tcx> {
                     .filter_map(|lib| lib.name.as_ref())
                     .any(|n| n.as_str() == lib.name);
                 if new_name.is_empty() {
-                    self.tcx.sess.err(format!(
-                        "an empty renaming target was specified for library `{}`",
-                        lib.name
-                    ));
+                    self.tcx.sess.emit_err(EmptyRenamingTarget { lib_name: &lib.name });
                 } else if !any_duplicate {
-                    self.tcx.sess.err(format!(
-                        "renaming of the library `{}` was specified, \
-                                                however this crate contains no `#[link(...)]` \
-                                                attributes referencing this library",
-                        lib.name
-                    ));
+                    self.tcx.sess.emit_err(RenamingNoLink { lib_name: &lib.name });
                 } else if !renames.insert(&lib.name) {
-                    self.tcx.sess.err(format!(
-                        "multiple renamings were \
-                                                specified for library `{}`",
-                        lib.name
-                    ));
+                    self.tcx.sess.emit_err(MultipleRenamings { lib_name: &lib.name });
                 }
             }
         }
@@ -480,10 +455,13 @@ impl<'tcx> Collector<'tcx> {
                             // involved or not, library reordering and kind overriding without
                             // explicit `:rename` in particular.
                             if lib.has_modifiers() || passed_lib.has_modifiers() {
-                                let msg = "overriding linking modifiers from command line is not supported";
                                 match lib.foreign_module {
-                                    Some(def_id) => self.tcx.sess.span_err(self.tcx.def_span(def_id), msg),
-                                    None => self.tcx.sess.err(msg),
+                                    Some(def_id) => self.tcx.sess.emit_err(NoLinkModOverride {
+                                        span: Some(self.tcx.def_span(def_id)),
+                                    }),
+                                    None => {
+                                        self.tcx.sess.emit_err(NoLinkModOverride { span: None })
+                                    }
                                 };
                             }
                             if passed_lib.kind != NativeLibKind::Unspecified {
@@ -502,8 +480,13 @@ impl<'tcx> Collector<'tcx> {
             if existing.is_empty() {
                 // Add if not found
                 let new_name: Option<&str> = passed_lib.new_name.as_deref();
+                let name = Some(Symbol::intern(new_name.unwrap_or(&passed_lib.name)));
+                let sess = self.tcx.sess;
+                let filename =
+                    find_bundled_library(name, passed_lib.verbatim, passed_lib.kind, sess);
                 self.libs.push(NativeLib {
-                    name: Some(Symbol::intern(new_name.unwrap_or(&passed_lib.name))),
+                    name,
+                    filename,
                     kind: passed_lib.kind,
                     cfg: None,
                     foreign_module: None,
@@ -562,32 +545,25 @@ impl<'tcx> Collector<'tcx> {
                     DllCallingConvention::Vectorcall(self.i686_arg_list_size(item))
                 }
                 _ => {
-                    self.tcx.sess.span_fatal(
-                        item.span,
-                        r#"ABI not supported by `#[link(kind = "raw-dylib")]` on i686"#,
-                    );
+                    self.tcx.sess.emit_fatal(UnsupportedAbiI686 { span: item.span });
                 }
             }
         } else {
             match abi {
                 Abi::C { .. } | Abi::Win64 { .. } | Abi::System { .. } => DllCallingConvention::C,
                 _ => {
-                    self.tcx.sess.span_fatal(
-                        item.span,
-                        r#"ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture"#,
-                    );
+                    self.tcx.sess.emit_fatal(UnsupportedAbi { span: item.span });
                 }
             }
         };
 
-        let import_name_type = self
-            .tcx
-            .codegen_fn_attrs(item.id.def_id)
+        let codegen_fn_attrs = self.tcx.codegen_fn_attrs(item.id.def_id);
+        let import_name_type = codegen_fn_attrs
             .link_ordinal
             .map_or(import_name_type, |ord| Some(PeImportNameType::Ordinal(ord)));
 
         DllImport {
-            name: item.ident.name,
+            name: codegen_fn_attrs.link_name.unwrap_or(item.ident.name),
             import_name_type,
             calling_convention,
             span: item.span,
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index d0e0aa91480c..830417eea1a0 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -4,7 +4,6 @@ use crate::creader::{CStore, CrateMetadataRef};
 use crate::rmeta::*;
 
 use rustc_ast as ast;
-use rustc_ast::ptr::P;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::svh::Svh;
@@ -33,7 +32,7 @@ use rustc_session::cstore::{
 use rustc_session::Session;
 use rustc_span::hygiene::{ExpnIndex, MacroKind};
 use rustc_span::source_map::{respan, Spanned};
-use rustc_span::symbol::{sym, Ident, Symbol};
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{self, BytePos, ExpnId, Pos, Span, SyntaxContext, DUMMY_SP};
 
 use proc_macro::bridge::client::ProcMacro;
@@ -42,7 +41,6 @@ use std::iter::TrustedLen;
 use std::mem;
 use std::num::NonZeroUsize;
 use std::path::Path;
-use tracing::debug;
 
 pub(super) use cstore_impl::provide;
 pub use cstore_impl::provide_extern;
@@ -452,6 +450,13 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ExpnIndex {
     }
 }
 
+impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ast::AttrId {
+    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> ast::AttrId {
+        let sess = d.sess.expect("can't decode AttrId without Session");
+        sess.parse_sess.attr_id_generator.mk_attr_id()
+    }
+}
+
 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for SyntaxContext {
     fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> SyntaxContext {
         let cdata = decoder.cdata();
@@ -786,26 +791,11 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.opt_item_ident(item_index, sess).expect("no encoded ident for item")
     }
 
-    fn maybe_kind(self, item_id: DefIndex) -> Option<EntryKind> {
-        self.root.tables.kind.get(self, item_id).map(|k| k.decode(self))
-    }
-
     #[inline]
     pub(super) fn map_encoded_cnum_to_current(self, cnum: CrateNum) -> CrateNum {
         if cnum == LOCAL_CRATE { self.cnum } else { self.cnum_map[cnum] }
     }
 
-    fn kind(self, item_id: DefIndex) -> EntryKind {
-        self.maybe_kind(item_id).unwrap_or_else(|| {
-            bug!(
-                "CrateMetadata::kind({:?}): id not found, in crate {:?} with number {}",
-                item_id,
-                self.root.name,
-                self.cnum,
-            )
-        })
-    }
-
     fn def_kind(self, item_id: DefIndex) -> DefKind {
         self.root.tables.opt_def_kind.get(self, item_id).unwrap_or_else(|| {
             bug!(
@@ -857,20 +847,15 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         )
     }
 
-    fn get_variant(self, kind: &EntryKind, index: DefIndex, parent_did: DefId) -> ty::VariantDef {
-        let data = match kind {
-            EntryKind::Variant(data) | EntryKind::Struct(data) | EntryKind::Union(data) => {
-                data.decode(self)
-            }
+    fn get_variant(self, kind: &DefKind, index: DefIndex, parent_did: DefId) -> ty::VariantDef {
+        let adt_kind = match kind {
+            DefKind::Variant => ty::AdtKind::Enum,
+            DefKind::Struct => ty::AdtKind::Struct,
+            DefKind::Union => ty::AdtKind::Union,
             _ => bug!(),
         };
 
-        let adt_kind = match kind {
-            EntryKind::Variant(_) => ty::AdtKind::Enum,
-            EntryKind::Struct(..) => ty::AdtKind::Struct,
-            EntryKind::Union(..) => ty::AdtKind::Union,
-            _ => bug!(),
-        };
+        let data = self.root.tables.variant_data.get(self, index).unwrap().decode(self);
 
         let variant_did =
             if adt_kind == ty::AdtKind::Enum { Some(self.local_def_id(index)) } else { None };
@@ -902,13 +887,13 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_adt_def(self, item_id: DefIndex, tcx: TyCtxt<'tcx>) -> ty::AdtDef<'tcx> {
-        let kind = self.kind(item_id);
+        let kind = self.def_kind(item_id);
         let did = self.local_def_id(item_id);
 
         let adt_kind = match kind {
-            EntryKind::Enum => ty::AdtKind::Enum,
-            EntryKind::Struct(_) => ty::AdtKind::Struct,
-            EntryKind::Union(_) => ty::AdtKind::Union,
+            DefKind::Enum => ty::AdtKind::Enum,
+            DefKind::Struct => ty::AdtKind::Struct,
+            DefKind::Union => ty::AdtKind::Union,
             _ => bug!("get_adt_def called on a non-ADT {:?}", did),
         };
         let repr = self.root.tables.repr_options.get(self, item_id).unwrap().decode(self);
@@ -920,7 +905,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                 .get(self, item_id)
                 .unwrap_or_else(LazyArray::empty)
                 .decode(self)
-                .map(|index| self.get_variant(&self.kind(index), index, did))
+                .map(|index| self.get_variant(&self.def_kind(index), index, did))
                 .collect()
         } else {
             std::iter::once(self.get_variant(&kind, item_id, did)).collect()
@@ -933,8 +918,14 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.root.tables.generics_of.get(self, item_id).unwrap().decode((self, sess))
     }
 
-    fn get_visibility(self, id: DefIndex) -> ty::Visibility {
-        self.root.tables.visibility.get(self, id).unwrap().decode(self)
+    fn get_visibility(self, id: DefIndex) -> ty::Visibility<DefId> {
+        self.root
+            .tables
+            .visibility
+            .get(self, id)
+            .unwrap()
+            .decode(self)
+            .map_id(|index| self.local_def_id(index))
     }
 
     fn get_trait_item_def_id(self, id: DefIndex) -> Option<DefId> {
@@ -1030,10 +1021,9 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                 let vis = self.get_visibility(child_index);
                 let span = self.get_span(child_index, sess);
                 let macro_rules = match kind {
-                    DefKind::Macro(..) => match self.kind(child_index) {
-                        EntryKind::MacroDef(_, macro_rules) => macro_rules,
-                        _ => unreachable!(),
-                    },
+                    DefKind::Macro(..) => {
+                        self.root.tables.macro_rules.get(self, child_index).is_some()
+                    }
                     _ => false,
                 };
 
@@ -1087,14 +1077,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             }
         }
 
-        match self.kind(id) {
-            EntryKind::Mod(exports) => {
-                for exp in exports.decode((self, sess)) {
-                    callback(exp);
-                }
+        if let Some(exports) = self.root.tables.module_reexports.get(self, id) {
+            for exp in exports.decode((self, sess)) {
+                callback(exp);
             }
-            EntryKind::Enum | EntryKind::Trait => {}
-            _ => bug!("`for_each_module_child` is called on a non-module: {:?}", self.def_kind(id)),
         }
     }
 
@@ -1107,19 +1093,21 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn module_expansion(self, id: DefIndex, sess: &Session) -> ExpnId {
-        match self.kind(id) {
-            EntryKind::Mod(_) | EntryKind::Enum | EntryKind::Trait => {
-                self.get_expn_that_defined(id, sess)
-            }
+        match self.def_kind(id) {
+            DefKind::Mod | DefKind::Enum | DefKind::Trait => self.get_expn_that_defined(id, sess),
             _ => panic!("Expected module, found {:?}", self.local_def_id(id)),
         }
     }
 
-    fn get_fn_has_self_parameter(self, id: DefIndex) -> bool {
-        match self.kind(id) {
-            EntryKind::AssocFn { has_self, .. } => has_self,
-            _ => false,
-        }
+    fn get_fn_has_self_parameter(self, id: DefIndex, sess: &'a Session) -> bool {
+        self.root
+            .tables
+            .fn_arg_names
+            .get(self, id)
+            .unwrap_or_else(LazyArray::empty)
+            .decode((self, sess))
+            .nth(0)
+            .map_or(false, |ident| ident.name == kw::SelfLower)
     }
 
     fn get_associated_item_def_ids(
@@ -1136,15 +1124,17 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .map(move |child_index| self.local_def_id(child_index))
     }
 
-    fn get_associated_item(self, id: DefIndex) -> ty::AssocItem {
+    fn get_associated_item(self, id: DefIndex, sess: &'a Session) -> ty::AssocItem {
         let name = self.item_name(id);
 
-        let (kind, container, has_self) = match self.kind(id) {
-            EntryKind::AssocConst(container) => (ty::AssocKind::Const, container, false),
-            EntryKind::AssocFn { container, has_self } => (ty::AssocKind::Fn, container, has_self),
-            EntryKind::AssocType(container) => (ty::AssocKind::Type, container, false),
-            _ => bug!("cannot get associated-item of `{:?}`", id),
+        let kind = match self.def_kind(id) {
+            DefKind::AssocConst => ty::AssocKind::Const,
+            DefKind::AssocFn => ty::AssocKind::Fn,
+            DefKind::AssocTy => ty::AssocKind::Type,
+            _ => bug!("cannot get associated-item of `{:?}`", self.def_key(id)),
         };
+        let has_self = self.get_fn_has_self_parameter(id, sess);
+        let container = self.root.tables.assoc_container.get(self, id).unwrap();
 
         ty::AssocItem {
             name,
@@ -1157,9 +1147,9 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_ctor_def_id_and_kind(self, node_id: DefIndex) -> Option<(DefId, CtorKind)> {
-        match self.kind(node_id) {
-            EntryKind::Struct(data) | EntryKind::Variant(data) => {
-                let vdata = data.decode(self);
+        match self.def_kind(node_id) {
+            DefKind::Struct | DefKind::Variant => {
+                let vdata = self.root.tables.variant_data.get(self, node_id).unwrap().decode(self);
                 vdata.ctor.map(|index| (self.local_def_id(index), vdata.ctor_kind))
             }
             _ => None,
@@ -1205,7 +1195,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .map(move |index| respan(self.get_span(index, sess), self.item_name(index)))
     }
 
-    fn get_struct_field_visibilities(self, id: DefIndex) -> impl Iterator<Item = Visibility> + 'a {
+    fn get_struct_field_visibilities(
+        self,
+        id: DefIndex,
+    ) -> impl Iterator<Item = Visibility<DefId>> + 'a {
         self.root
             .tables
             .children
@@ -1347,18 +1340,22 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_macro(self, id: DefIndex, sess: &Session) -> ast::MacroDef {
-        match self.kind(id) {
-            EntryKind::MacroDef(mac_args, macro_rules) => {
-                ast::MacroDef { body: P(mac_args.decode((self, sess))), macro_rules }
+        match self.def_kind(id) {
+            DefKind::Macro(_) => {
+                let macro_rules = self.root.tables.macro_rules.get(self, id).is_some();
+                let body =
+                    self.root.tables.macro_definition.get(self, id).unwrap().decode((self, sess));
+                ast::MacroDef { macro_rules, body: ast::ptr::P(body) }
             }
             _ => bug!(),
         }
     }
 
     fn is_foreign_item(self, id: DefIndex) -> bool {
-        match self.kind(id) {
-            EntryKind::ForeignStatic | EntryKind::ForeignFn => true,
-            _ => false,
+        if let Some(parent) = self.def_key(id).parent {
+            matches!(self.def_kind(parent), DefKind::ForeignMod)
+        } else {
+            false
         }
     }
 
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 9d201a0c7999..dede1b2122a3 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -210,7 +210,6 @@ provide! { tcx, def_id, other, cdata,
     lookup_const_stability => { table }
     lookup_default_body_stability => { table }
     lookup_deprecation_entry => { table }
-    visibility => { table }
     unused_generic_params => { table }
     opt_def_kind => { table_direct }
     impl_parent => { table }
@@ -225,6 +224,7 @@ provide! { tcx, def_id, other, cdata,
     generator_kind => { table }
     trait_def => { table }
 
+    visibility => { cdata.get_visibility(def_id.index) }
     adt_def => { cdata.get_adt_def(def_id.index, tcx) }
     adt_destructor => {
         let _ = cdata;
@@ -233,7 +233,7 @@ provide! { tcx, def_id, other, cdata,
     associated_item_def_ids => {
         tcx.arena.alloc_from_iter(cdata.get_associated_item_def_ids(def_id.index, tcx.sess))
     }
-    associated_item => { cdata.get_associated_item(def_id.index) }
+    associated_item => { cdata.get_associated_item(def_id.index, tcx.sess) }
     inherent_impls => { cdata.get_inherent_implementations_for_type(tcx, def_id.index) }
     is_foreign_item => { cdata.is_foreign_item(def_id.index) }
     item_attrs => { tcx.arena.alloc_from_iter(cdata.get_item_attrs(def_id.index, tcx.sess)) }
@@ -485,7 +485,7 @@ impl CStore {
     pub fn struct_field_visibilities_untracked(
         &self,
         def: DefId,
-    ) -> impl Iterator<Item = Visibility> + '_ {
+    ) -> impl Iterator<Item = Visibility<DefId>> + '_ {
         self.get_crate_data(def.krate).get_struct_field_visibilities(def.index)
     }
 
@@ -493,7 +493,7 @@ impl CStore {
         self.get_crate_data(def.krate).get_ctor_def_id_and_kind(def.index)
     }
 
-    pub fn visibility_untracked(&self, def: DefId) -> Visibility {
+    pub fn visibility_untracked(&self, def: DefId) -> Visibility<DefId> {
         self.get_crate_data(def.krate).get_visibility(def.index)
     }
 
@@ -535,8 +535,8 @@ impl CStore {
         )
     }
 
-    pub fn fn_has_self_parameter_untracked(&self, def: DefId) -> bool {
-        self.get_crate_data(def.krate).get_fn_has_self_parameter(def.index)
+    pub fn fn_has_self_parameter_untracked(&self, def: DefId, sess: &Session) -> bool {
+        self.get_crate_data(def.krate).get_fn_has_self_parameter(def.index, sess)
     }
 
     pub fn crate_source_untracked(&self, cnum: CrateNum) -> Lrc<CrateSource> {
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 3482d9f04514..7cf00ca41fef 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1,3 +1,4 @@
+use crate::errors::{FailCreateFileEncoder, FailSeekFile, FailWriteFile};
 use crate::rmeta::def_path_hash_map::DefPathHashMapRef;
 use crate::rmeta::table::TableBuilder;
 use crate::rmeta::*;
@@ -16,7 +17,6 @@ use rustc_hir::def_id::{
 use rustc_hir::definitions::DefPathData;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::lang_items;
-use rustc_hir::{AnonConst, GenericParamKind};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::{
@@ -28,6 +28,7 @@ use rustc_middle::ty::codec::TyEncoder;
 use rustc_middle::ty::fast_reject::{self, SimplifiedType, TreatParams};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, SymbolName, Ty, TyCtxt};
+use rustc_middle::util::common::to_readable_str;
 use rustc_serialize::{opaque, Decodable, Decoder, Encodable, Encoder};
 use rustc_session::config::CrateType;
 use rustc_session::cstore::{ForeignModule, LinkagePreference, NativeLib};
@@ -44,7 +45,6 @@ use std::io::{Read, Seek, Write};
 use std::iter;
 use std::num::NonZeroUsize;
 use std::path::{Path, PathBuf};
-use tracing::{debug, trace};
 
 pub(super) struct EncodeContext<'a, 'tcx> {
     opaque: opaque::FileEncoder,
@@ -262,10 +262,10 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
         // This allows us to avoid loading the dependencies of proc-macro crates: all of
         // the information we need to decode `Span`s is stored in the proc-macro crate.
         let (tag, metadata_index) = if source_file.is_imported() && !s.is_proc_macro {
-            // To simplify deserialization, we 'rebase' this span onto the crate it originally came from
-            // (the crate that 'owns' the file it references. These rebased 'lo' and 'hi' values
-            // are relative to the source map information for the 'foreign' crate whose CrateNum
-            // we write into the metadata. This allows `imported_source_files` to binary
+            // To simplify deserialization, we 'rebase' this span onto the crate it originally came
+            // from (the crate that 'owns' the file it references. These rebased 'lo' and 'hi'
+            // values are relative to the source map information for the 'foreign' crate whose
+            // CrateNum we write into the metadata. This allows `imported_source_files` to binary
             // search through the 'foreign' crate's source map information, using the
             // deserialized 'lo' and 'hi' values directly.
             //
@@ -555,78 +555,56 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
     fn encode_crate_root(&mut self) -> LazyValue<CrateRoot> {
         let tcx = self.tcx;
-        let mut i = 0;
-        let preamble_bytes = self.position() - i;
+        let mut stats: Vec<(&'static str, usize)> = Vec::with_capacity(32);
 
-        // Encode the crate deps
-        i = self.position();
-        let crate_deps = self.encode_crate_deps();
-        let dylib_dependency_formats = self.encode_dylib_dependency_formats();
-        let dep_bytes = self.position() - i;
+        macro_rules! stat {
+            ($label:literal, $f:expr) => {{
+                let orig_pos = self.position();
+                let res = $f();
+                stats.push(($label, self.position() - orig_pos));
+                res
+            }};
+        }
 
-        // Encode the lib features.
-        i = self.position();
-        let lib_features = self.encode_lib_features();
-        let lib_feature_bytes = self.position() - i;
+        // We have already encoded some things. Get their combined size from the current position.
+        stats.push(("preamble", self.position()));
 
-        // Encode the stability implications.
-        i = self.position();
-        let stability_implications = self.encode_stability_implications();
-        let stability_implications_bytes = self.position() - i;
+        let (crate_deps, dylib_dependency_formats) =
+            stat!("dep", || (self.encode_crate_deps(), self.encode_dylib_dependency_formats()));
 
-        // Encode the language items.
-        i = self.position();
-        let lang_items = self.encode_lang_items();
-        let lang_items_missing = self.encode_lang_items_missing();
-        let lang_item_bytes = self.position() - i;
+        let lib_features = stat!("lib-features", || self.encode_lib_features());
 
-        // Encode the diagnostic items.
-        i = self.position();
-        let diagnostic_items = self.encode_diagnostic_items();
-        let diagnostic_item_bytes = self.position() - i;
+        let stability_implications =
+            stat!("stability-implications", || self.encode_stability_implications());
 
-        // Encode the native libraries used
-        i = self.position();
-        let native_libraries = self.encode_native_libraries();
-        let native_lib_bytes = self.position() - i;
+        let (lang_items, lang_items_missing) = stat!("lang-items", || {
+            (self.encode_lang_items(), self.encode_lang_items_missing())
+        });
 
-        i = self.position();
-        let foreign_modules = self.encode_foreign_modules();
-        let foreign_modules_bytes = self.position() - i;
+        let diagnostic_items = stat!("diagnostic-items", || self.encode_diagnostic_items());
 
-        // Encode DefPathTable
-        i = self.position();
-        self.encode_def_path_table();
-        let def_path_table_bytes = self.position() - i;
+        let native_libraries = stat!("native-libs", || self.encode_native_libraries());
+
+        let foreign_modules = stat!("foreign-modules", || self.encode_foreign_modules());
+
+        _ = stat!("def-path-table", || self.encode_def_path_table());
 
         // Encode the def IDs of traits, for rustdoc and diagnostics.
-        i = self.position();
-        let traits = self.encode_traits();
-        let traits_bytes = self.position() - i;
+        let traits = stat!("traits", || self.encode_traits());
 
         // Encode the def IDs of impls, for coherence checking.
-        i = self.position();
-        let impls = self.encode_impls();
-        let impls_bytes = self.position() - i;
+        let impls = stat!("impls", || self.encode_impls());
 
-        i = self.position();
-        let incoherent_impls = self.encode_incoherent_impls();
-        let incoherent_impls_bytes = self.position() - i;
+        let incoherent_impls = stat!("incoherent-impls", || self.encode_incoherent_impls());
 
-        // Encode MIR.
-        i = self.position();
-        self.encode_mir();
-        let mir_bytes = self.position() - i;
+        _ = stat!("mir", || self.encode_mir());
 
-        // Encode the items.
-        i = self.position();
-        self.encode_def_ids();
-        self.encode_info_for_items();
-        let item_bytes = self.position() - i;
+        _ = stat!("items", || {
+            self.encode_def_ids();
+            self.encode_info_for_items();
+        });
 
-        // Encode the allocation index
-        i = self.position();
-        let interpret_alloc_index = {
+        let interpret_alloc_index = stat!("interpret-alloc-index", || {
             let mut interpret_alloc_index = Vec::new();
             let mut n = 0;
             trace!("beginning to encode alloc ids");
@@ -647,126 +625,90 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 n = new_n;
             }
             self.lazy_array(interpret_alloc_index)
-        };
-        let interpret_alloc_index_bytes = self.position() - i;
+        });
 
-        // Encode the proc macro data. This affects 'tables',
-        // so we need to do this before we encode the tables.
-        // This overwrites def_keys, so it must happen after encode_def_path_table.
-        i = self.position();
-        let proc_macro_data = self.encode_proc_macros();
-        let proc_macro_data_bytes = self.position() - i;
+        // Encode the proc macro data. This affects `tables`, so we need to do this before we
+        // encode the tables. This overwrites def_keys, so it must happen after
+        // encode_def_path_table.
+        let proc_macro_data = stat!("proc-macro-data", || self.encode_proc_macros());
 
-        i = self.position();
-        let tables = self.tables.encode(&mut self.opaque);
-        let tables_bytes = self.position() - i;
+        let tables = stat!("tables", || self.tables.encode(&mut self.opaque));
 
-        i = self.position();
-        let debugger_visualizers = self.encode_debugger_visualizers();
-        let debugger_visualizers_bytes = self.position() - i;
+        let debugger_visualizers =
+            stat!("debugger-visualizers", || self.encode_debugger_visualizers());
 
         // Encode exported symbols info. This is prefetched in `encode_metadata` so we encode
         // this as late as possible to give the prefetching as much time as possible to complete.
-        i = self.position();
-        let exported_symbols = tcx.exported_symbols(LOCAL_CRATE);
-        let exported_symbols = self.encode_exported_symbols(&exported_symbols);
-        let exported_symbols_bytes = self.position() - i;
-
-        // Encode the hygiene data,
-        // IMPORTANT: this *must* be the last thing that we encode (other than `SourceMap`). The process
-        // of encoding other items (e.g. `optimized_mir`) may cause us to load
-        // data from the incremental cache. If this causes us to deserialize a `Span`,
-        // then we may load additional `SyntaxContext`s into the global `HygieneData`.
-        // Therefore, we need to encode the hygiene data last to ensure that we encode
-        // any `SyntaxContext`s that might be used.
-        i = self.position();
-        let (syntax_contexts, expn_data, expn_hashes) = self.encode_hygiene();
-        let hygiene_bytes = self.position() - i;
-
-        i = self.position();
-        let def_path_hash_map = self.encode_def_path_hash_map();
-        let def_path_hash_map_bytes = self.position() - i;
-
-        // Encode source_map. This needs to be done last,
-        // since encoding `Span`s tells us which `SourceFiles` we actually
-        // need to encode.
-        i = self.position();
-        let source_map = self.encode_source_map();
-        let source_map_bytes = self.position() - i;
-
-        i = self.position();
-        let attrs = tcx.hir().krate_attrs();
-        let has_default_lib_allocator = tcx.sess.contains_name(&attrs, sym::default_lib_allocator);
-        let root = self.lazy(CrateRoot {
-            name: tcx.crate_name(LOCAL_CRATE),
-            extra_filename: tcx.sess.opts.cg.extra_filename.clone(),
-            triple: tcx.sess.opts.target_triple.clone(),
-            hash: tcx.crate_hash(LOCAL_CRATE),
-            stable_crate_id: tcx.def_path_hash(LOCAL_CRATE.as_def_id()).stable_crate_id(),
-            required_panic_strategy: tcx.required_panic_strategy(LOCAL_CRATE),
-            panic_in_drop_strategy: tcx.sess.opts.unstable_opts.panic_in_drop,
-            edition: tcx.sess.edition(),
-            has_global_allocator: tcx.has_global_allocator(LOCAL_CRATE),
-            has_panic_handler: tcx.has_panic_handler(LOCAL_CRATE),
-            has_default_lib_allocator,
-            proc_macro_data,
-            debugger_visualizers,
-            compiler_builtins: tcx.sess.contains_name(&attrs, sym::compiler_builtins),
-            needs_allocator: tcx.sess.contains_name(&attrs, sym::needs_allocator),
-            needs_panic_runtime: tcx.sess.contains_name(&attrs, sym::needs_panic_runtime),
-            no_builtins: tcx.sess.contains_name(&attrs, sym::no_builtins),
-            panic_runtime: tcx.sess.contains_name(&attrs, sym::panic_runtime),
-            profiler_runtime: tcx.sess.contains_name(&attrs, sym::profiler_runtime),
-            symbol_mangling_version: tcx.sess.opts.get_symbol_mangling_version(),
-
-            crate_deps,
-            dylib_dependency_formats,
-            lib_features,
-            stability_implications,
-            lang_items,
-            diagnostic_items,
-            lang_items_missing,
-            native_libraries,
-            foreign_modules,
-            source_map,
-            traits,
-            impls,
-            incoherent_impls,
-            exported_symbols,
-            interpret_alloc_index,
-            tables,
-            syntax_contexts,
-            expn_data,
-            expn_hashes,
-            def_path_hash_map,
+        let exported_symbols = stat!("exported-symbols", || {
+            self.encode_exported_symbols(&tcx.exported_symbols(LOCAL_CRATE))
+        });
+
+        // Encode the hygiene data.
+        // IMPORTANT: this *must* be the last thing that we encode (other than `SourceMap`). The
+        // process of encoding other items (e.g. `optimized_mir`) may cause us to load data from
+        // the incremental cache. If this causes us to deserialize a `Span`, then we may load
+        // additional `SyntaxContext`s into the global `HygieneData`. Therefore, we need to encode
+        // the hygiene data last to ensure that we encode any `SyntaxContext`s that might be used.
+        let (syntax_contexts, expn_data, expn_hashes) = stat!("hygiene", || self.encode_hygiene());
+
+        let def_path_hash_map = stat!("def-path-hash-map", || self.encode_def_path_hash_map());
+
+        // Encode source_map. This needs to be done last, because encoding `Span`s tells us which
+        // `SourceFiles` we actually need to encode.
+        let source_map = stat!("source-map", || self.encode_source_map());
+
+        let root = stat!("final", || {
+            let attrs = tcx.hir().krate_attrs();
+            self.lazy(CrateRoot {
+                name: tcx.crate_name(LOCAL_CRATE),
+                extra_filename: tcx.sess.opts.cg.extra_filename.clone(),
+                triple: tcx.sess.opts.target_triple.clone(),
+                hash: tcx.crate_hash(LOCAL_CRATE),
+                stable_crate_id: tcx.def_path_hash(LOCAL_CRATE.as_def_id()).stable_crate_id(),
+                required_panic_strategy: tcx.required_panic_strategy(LOCAL_CRATE),
+                panic_in_drop_strategy: tcx.sess.opts.unstable_opts.panic_in_drop,
+                edition: tcx.sess.edition(),
+                has_global_allocator: tcx.has_global_allocator(LOCAL_CRATE),
+                has_panic_handler: tcx.has_panic_handler(LOCAL_CRATE),
+                has_default_lib_allocator: tcx
+                    .sess
+                    .contains_name(&attrs, sym::default_lib_allocator),
+                proc_macro_data,
+                debugger_visualizers,
+                compiler_builtins: tcx.sess.contains_name(&attrs, sym::compiler_builtins),
+                needs_allocator: tcx.sess.contains_name(&attrs, sym::needs_allocator),
+                needs_panic_runtime: tcx.sess.contains_name(&attrs, sym::needs_panic_runtime),
+                no_builtins: tcx.sess.contains_name(&attrs, sym::no_builtins),
+                panic_runtime: tcx.sess.contains_name(&attrs, sym::panic_runtime),
+                profiler_runtime: tcx.sess.contains_name(&attrs, sym::profiler_runtime),
+                symbol_mangling_version: tcx.sess.opts.get_symbol_mangling_version(),
+
+                crate_deps,
+                dylib_dependency_formats,
+                lib_features,
+                stability_implications,
+                lang_items,
+                diagnostic_items,
+                lang_items_missing,
+                native_libraries,
+                foreign_modules,
+                source_map,
+                traits,
+                impls,
+                incoherent_impls,
+                exported_symbols,
+                interpret_alloc_index,
+                tables,
+                syntax_contexts,
+                expn_data,
+                expn_hashes,
+                def_path_hash_map,
+            })
         });
-        let final_bytes = self.position() - i;
 
         let total_bytes = self.position();
 
-        let computed_total_bytes = preamble_bytes
-            + dep_bytes
-            + lib_feature_bytes
-            + stability_implications_bytes
-            + lang_item_bytes
-            + diagnostic_item_bytes
-            + native_lib_bytes
-            + foreign_modules_bytes
-            + def_path_table_bytes
-            + traits_bytes
-            + impls_bytes
-            + incoherent_impls_bytes
-            + mir_bytes
-            + item_bytes
-            + interpret_alloc_index_bytes
-            + proc_macro_data_bytes
-            + tables_bytes
-            + debugger_visualizers_bytes
-            + exported_symbols_bytes
-            + hygiene_bytes
-            + def_path_hash_map_bytes
-            + source_map_bytes
-            + final_bytes;
+        let computed_total_bytes: usize = stats.iter().map(|(_, size)| size).sum();
         assert_eq!(total_bytes, computed_total_bytes);
 
         if tcx.sess.meta_stats() {
@@ -784,42 +726,38 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             }
             assert_eq!(self.opaque.file().stream_position().unwrap(), pos_before_rewind);
 
-            let perc = |bytes| (bytes * 100) as f64 / total_bytes as f64;
-            let p = |label, bytes| {
-                eprintln!("{:>21}: {:>8} bytes ({:4.1}%)", label, bytes, perc(bytes));
-            };
+            stats.sort_by_key(|&(_, usize)| usize);
 
-            eprintln!("");
+            let prefix = "meta-stats";
+            let perc = |bytes| (bytes * 100) as f64 / total_bytes as f64;
+
+            eprintln!("{} METADATA STATS", prefix);
+            eprintln!("{} {:<23}{:>10}", prefix, "Section", "Size");
             eprintln!(
-                "{} metadata bytes, of which {} bytes ({:.1}%) are zero",
-                total_bytes,
-                zero_bytes,
+                "{} ----------------------------------------------------------------",
+                prefix
+            );
+            for (label, size) in stats {
+                eprintln!(
+                    "{} {:<23}{:>10} ({:4.1}%)",
+                    prefix,
+                    label,
+                    to_readable_str(size),
+                    perc(size)
+                );
+            }
+            eprintln!(
+                "{} ----------------------------------------------------------------",
+                prefix
+            );
+            eprintln!(
+                "{} {:<23}{:>10} (of which {:.1}% are zero bytes)",
+                prefix,
+                "Total",
+                to_readable_str(total_bytes),
                 perc(zero_bytes)
             );
-            p("preamble", preamble_bytes);
-            p("dep", dep_bytes);
-            p("lib feature", lib_feature_bytes);
-            p("stability_implications", stability_implications_bytes);
-            p("lang item", lang_item_bytes);
-            p("diagnostic item", diagnostic_item_bytes);
-            p("native lib", native_lib_bytes);
-            p("foreign modules", foreign_modules_bytes);
-            p("def-path table", def_path_table_bytes);
-            p("traits", traits_bytes);
-            p("impls", impls_bytes);
-            p("incoherent_impls", incoherent_impls_bytes);
-            p("mir", mir_bytes);
-            p("item", item_bytes);
-            p("interpret_alloc_index", interpret_alloc_index_bytes);
-            p("proc-macro-data", proc_macro_data_bytes);
-            p("tables", tables_bytes);
-            p("debugger visualizers", debugger_visualizers_bytes);
-            p("exported symbols", exported_symbols_bytes);
-            p("hygiene", hygiene_bytes);
-            p("def-path hashes", def_path_hash_map_bytes);
-            p("source_map", source_map_bytes);
-            p("final", final_bytes);
-            eprintln!("");
+            eprintln!("{}", prefix);
         }
 
         root
@@ -848,6 +786,7 @@ fn should_encode_visibility(def_kind: DefKind) -> bool {
         | DefKind::Use
         | DefKind::ForeignMod
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Impl
         | DefKind::Field => true,
         DefKind::TyParam
@@ -880,6 +819,7 @@ fn should_encode_stability(def_kind: DefKind) -> bool {
         | DefKind::ForeignMod
         | DefKind::TyAlias
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Enum
         | DefKind::Union
         | DefKind::Impl
@@ -968,6 +908,7 @@ fn should_encode_variances(def_kind: DefKind) -> bool {
         | DefKind::ForeignMod
         | DefKind::TyAlias
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Impl
         | DefKind::Trait
         | DefKind::TraitAlias
@@ -1004,6 +945,7 @@ fn should_encode_generics(def_kind: DefKind) -> bool {
         | DefKind::AnonConst
         | DefKind::InlineConst
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Impl
         | DefKind::Field
         | DefKind::TyParam
@@ -1020,6 +962,103 @@ fn should_encode_generics(def_kind: DefKind) -> bool {
     }
 }
 
+fn should_encode_type(tcx: TyCtxt<'_>, def_id: LocalDefId, def_kind: DefKind) -> bool {
+    match def_kind {
+        DefKind::Struct
+        | DefKind::Union
+        | DefKind::Enum
+        | DefKind::Variant
+        | DefKind::Ctor(..)
+        | DefKind::Field
+        | DefKind::Fn
+        | DefKind::Const
+        | DefKind::Static(..)
+        | DefKind::TyAlias
+        | DefKind::OpaqueTy
+        | DefKind::ForeignTy
+        | DefKind::Impl
+        | DefKind::AssocFn
+        | DefKind::AssocConst
+        | DefKind::Closure
+        | DefKind::Generator
+        | DefKind::ConstParam
+        | DefKind::AnonConst
+        | DefKind::InlineConst => true,
+
+        DefKind::ImplTraitPlaceholder => {
+            let parent_def_id = tcx.impl_trait_in_trait_parent(def_id.to_def_id());
+            let assoc_item = tcx.associated_item(parent_def_id);
+            match assoc_item.container {
+                // Always encode an RPIT in an impl fn, since it always has a body
+                ty::AssocItemContainer::ImplContainer => true,
+                ty::AssocItemContainer::TraitContainer => {
+                    // Encode an RPIT for a trait only if the trait has a default body
+                    assoc_item.defaultness(tcx).has_value()
+                }
+            }
+        }
+
+        DefKind::AssocTy => {
+            let assoc_item = tcx.associated_item(def_id);
+            match assoc_item.container {
+                ty::AssocItemContainer::ImplContainer => true,
+                ty::AssocItemContainer::TraitContainer => assoc_item.defaultness(tcx).has_value(),
+            }
+        }
+        DefKind::TyParam => {
+            let hir::Node::GenericParam(param) = tcx.hir().get_by_def_id(def_id) else { bug!() };
+            let hir::GenericParamKind::Type { default, .. } = param.kind else { bug!() };
+            default.is_some()
+        }
+
+        DefKind::Trait
+        | DefKind::TraitAlias
+        | DefKind::Mod
+        | DefKind::ForeignMod
+        | DefKind::Macro(..)
+        | DefKind::Use
+        | DefKind::LifetimeParam
+        | DefKind::GlobalAsm
+        | DefKind::ExternCrate => false,
+    }
+}
+
+fn should_encode_const(def_kind: DefKind) -> bool {
+    match def_kind {
+        DefKind::Const | DefKind::AssocConst | DefKind::AnonConst => true,
+
+        DefKind::Struct
+        | DefKind::Union
+        | DefKind::Enum
+        | DefKind::Variant
+        | DefKind::Ctor(..)
+        | DefKind::Field
+        | DefKind::Fn
+        | DefKind::Static(..)
+        | DefKind::TyAlias
+        | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
+        | DefKind::ForeignTy
+        | DefKind::Impl
+        | DefKind::AssocFn
+        | DefKind::Closure
+        | DefKind::Generator
+        | DefKind::ConstParam
+        | DefKind::InlineConst
+        | DefKind::AssocTy
+        | DefKind::TyParam
+        | DefKind::Trait
+        | DefKind::TraitAlias
+        | DefKind::Mod
+        | DefKind::ForeignMod
+        | DefKind::Macro(..)
+        | DefKind::Use
+        | DefKind::LifetimeParam
+        | DefKind::GlobalAsm
+        | DefKind::ExternCrate => false,
+    }
+}
+
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     fn encode_attrs(&mut self, def_id: LocalDefId) {
         let mut attrs = self
@@ -1045,7 +1084,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             let def_kind = tcx.opt_def_kind(local_id);
             let Some(def_kind) = def_kind else { continue };
             self.tables.opt_def_kind.set(def_id.index, def_kind);
-            record!(self.tables.def_span[def_id] <- tcx.def_span(def_id));
+            let def_span = tcx.def_span(local_id);
+            record!(self.tables.def_span[def_id] <- def_span);
             self.encode_attrs(local_id);
             record!(self.tables.expn_that_defined[def_id] <- self.tcx.expn_that_defined(def_id));
             if let Some(ident_span) = tcx.def_ident_span(def_id) {
@@ -1055,7 +1095,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.codegen_fn_attrs[def_id] <- self.tcx.codegen_fn_attrs(def_id));
             }
             if should_encode_visibility(def_kind) {
-                record!(self.tables.visibility[def_id] <- self.tcx.visibility(def_id));
+                let vis =
+                    self.tcx.local_visibility(local_id).map_id(|def_id| def_id.local_def_index);
+                record!(self.tables.visibility[def_id] <- vis);
             }
             if should_encode_stability(def_kind) {
                 self.encode_stability(def_id);
@@ -1076,10 +1118,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     record_array!(self.tables.inferred_outlives_of[def_id] <- inferred_outlives);
                 }
             }
-            if let DefKind::TyParam | DefKind::ConstParam = def_kind {
-                if let Some(default) = self.tcx.object_lifetime_default(def_id) {
-                    record!(self.tables.object_lifetime_default[def_id] <- default);
-                }
+            if should_encode_type(tcx, local_id, def_kind) {
+                record!(self.tables.type_of[def_id] <- self.tcx.type_of(def_id));
+            }
+            if let DefKind::TyParam = def_kind {
+                let default = self.tcx.object_lifetime_default(def_id);
+                record!(self.tables.object_lifetime_default[def_id] <- default);
             }
             if let DefKind::Trait | DefKind::TraitAlias = def_kind {
                 record!(self.tables.super_predicates_of[def_id] <- self.tcx.super_predicates_of(def_id));
@@ -1097,11 +1141,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
     }
 
-    fn encode_item_type(&mut self, def_id: DefId) {
-        debug!("EncodeContext::encode_item_type({:?})", def_id);
-        record!(self.tables.type_of[def_id] <- self.tcx.type_of(def_id));
-    }
-
     fn encode_enum_variant_info(&mut self, def: ty::AdtDef<'tcx>, index: VariantIdx) {
         let tcx = self.tcx;
         let variant = &def.variant(index);
@@ -1115,13 +1154,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             is_non_exhaustive: variant.is_field_list_non_exhaustive(),
         };
 
-        record!(self.tables.kind[def_id] <- EntryKind::Variant(self.lazy(data)));
+        record!(self.tables.variant_data[def_id] <- data);
         self.tables.constness.set(def_id.index, hir::Constness::Const);
         record_array!(self.tables.children[def_id] <- variant.fields.iter().map(|f| {
             assert!(f.did.is_local());
             f.did.index
         }));
-        self.encode_item_type(def_id);
         if variant.ctor_kind == CtorKind::Fn {
             // FIXME(eddyb) encode signature only in `encode_enum_variant_ctor`.
             if let Some(ctor_def_id) = variant.ctor_def_id {
@@ -1144,9 +1182,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             is_non_exhaustive: variant.is_field_list_non_exhaustive(),
         };
 
-        record!(self.tables.kind[def_id] <- EntryKind::Variant(self.lazy(data)));
+        record!(self.tables.variant_data[def_id] <- data);
         self.tables.constness.set(def_id.index, hir::Constness::Const);
-        self.encode_item_type(def_id);
         if variant.ctor_kind == CtorKind::Fn {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
         }
@@ -1163,15 +1200,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         // code uses it). However, we skip encoding anything relating to child
         // items - we encode information about proc-macros later on.
         let reexports = if !self.is_proc_macro {
-            match tcx.module_reexports(local_def_id) {
-                Some(exports) => self.lazy_array(exports),
-                _ => LazyArray::empty(),
-            }
+            tcx.module_reexports(local_def_id).unwrap_or(&[])
         } else {
-            LazyArray::empty()
+            &[]
         };
 
-        record!(self.tables.kind[def_id] <- EntryKind::Mod(reexports));
+        record_array!(self.tables.module_reexports[def_id] <- reexports);
         if self.is_proc_macro {
             // Encode this here because we don't do it in encode_def_ids.
             record!(self.tables.expn_that_defined[def_id] <- tcx.expn_that_defined(local_def_id));
@@ -1183,14 +1217,14 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                         // from name resolution point of view.
                         hir::ItemKind::ForeignMod { items, .. } => {
                             for foreign_item in items {
-                                yield foreign_item.id.def_id.local_def_index;
+                                yield foreign_item.id.def_id.def_id.local_def_index;
                             }
                         }
                         // Only encode named non-reexport children, reexports are encoded
                         // separately and unnamed items are not used by name resolution.
                         hir::ItemKind::ExternCrate(..) => continue,
                         _ if tcx.def_key(item_id.def_id.to_def_id()).get_opt_name().is_some() => {
-                            yield item_id.def_id.local_def_index;
+                            yield item_id.def_id.def_id.local_def_index;
                         }
                         _ => continue,
                     }
@@ -1199,22 +1233,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
     }
 
-    fn encode_field(
-        &mut self,
-        adt_def: ty::AdtDef<'tcx>,
-        variant_index: VariantIdx,
-        field_index: usize,
-    ) {
-        let variant = &adt_def.variant(variant_index);
-        let field = &variant.fields[field_index];
-
-        let def_id = field.did;
-        debug!("EncodeContext::encode_field({:?})", def_id);
-
-        record!(self.tables.kind[def_id] <- EntryKind::Field);
-        self.encode_item_type(def_id);
-    }
-
     fn encode_struct_ctor(&mut self, adt_def: ty::AdtDef<'tcx>, def_id: DefId) {
         debug!("EncodeContext::encode_struct_ctor({:?})", def_id);
         let tcx = self.tcx;
@@ -1228,9 +1246,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         };
 
         record!(self.tables.repr_options[def_id] <- adt_def.repr());
+        record!(self.tables.variant_data[def_id] <- data);
         self.tables.constness.set(def_id.index, hir::Constness::Const);
-        record!(self.tables.kind[def_id] <- EntryKind::Struct(self.lazy(data)));
-        self.encode_item_type(def_id);
         if variant.ctor_kind == CtorKind::Fn {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
         }
@@ -1251,18 +1268,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         let ast_item = tcx.hir().expect_trait_item(def_id.expect_local());
         self.tables.impl_defaultness.set(def_id.index, ast_item.defaultness);
         let trait_item = tcx.associated_item(def_id);
+        self.tables.assoc_container.set(def_id.index, trait_item.container);
 
         match trait_item.kind {
-            ty::AssocKind::Const => {
-                let rendered = rustc_hir_pretty::to_string(
-                    &(&self.tcx.hir() as &dyn intravisit::Map<'_>),
-                    |s| s.print_trait_item(ast_item),
-                );
-
-                record!(self.tables.kind[def_id] <- EntryKind::AssocConst(ty::AssocItemContainer::TraitContainer));
-                record!(self.tables.mir_const_qualif[def_id] <- mir::ConstQualifs::default());
-                record!(self.tables.rendered_const[def_id] <- rendered);
-            }
+            ty::AssocKind::Const => {}
             ty::AssocKind::Fn => {
                 let hir::TraitItemKind::Fn(m_sig, m) = &ast_item.kind else { bug!() };
                 match *m {
@@ -1275,24 +1284,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 };
                 self.tables.asyncness.set(def_id.index, m_sig.header.asyncness);
                 self.tables.constness.set(def_id.index, hir::Constness::NotConst);
-                record!(self.tables.kind[def_id] <- EntryKind::AssocFn {
-                    container: ty::AssocItemContainer::TraitContainer,
-                    has_self: trait_item.fn_has_self_parameter,
-                });
             }
             ty::AssocKind::Type => {
                 self.encode_explicit_item_bounds(def_id);
-                record!(self.tables.kind[def_id] <- EntryKind::AssocType(ty::AssocItemContainer::TraitContainer));
-            }
-        }
-        match trait_item.kind {
-            ty::AssocKind::Const | ty::AssocKind::Fn => {
-                self.encode_item_type(def_id);
-            }
-            ty::AssocKind::Type => {
-                if ast_item.defaultness.has_value() {
-                    self.encode_item_type(def_id);
-                }
             }
         }
         if trait_item.kind == ty::AssocKind::Fn {
@@ -1307,20 +1301,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         let ast_item = self.tcx.hir().expect_impl_item(def_id.expect_local());
         self.tables.impl_defaultness.set(def_id.index, ast_item.defaultness);
         let impl_item = self.tcx.associated_item(def_id);
+        self.tables.assoc_container.set(def_id.index, impl_item.container);
 
         match impl_item.kind {
-            ty::AssocKind::Const => {
-                if let hir::ImplItemKind::Const(_, body_id) = ast_item.kind {
-                    let qualifs = self.tcx.at(ast_item.span).mir_const_qualif(def_id);
-                    let const_data = self.encode_rendered_const_for_body(body_id);
-
-                    record!(self.tables.kind[def_id] <- EntryKind::AssocConst(ty::AssocItemContainer::ImplContainer));
-                    record!(self.tables.mir_const_qualif[def_id] <- qualifs);
-                    record!(self.tables.rendered_const[def_id] <- const_data);
-                } else {
-                    bug!()
-                }
-            }
             ty::AssocKind::Fn => {
                 let hir::ImplItemKind::Fn(ref sig, body) = ast_item.kind else { bug!() };
                 self.tables.asyncness.set(def_id.index, sig.header.asyncness);
@@ -1332,16 +1315,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     hir::Constness::NotConst
                 };
                 self.tables.constness.set(def_id.index, constness);
-                record!(self.tables.kind[def_id] <- EntryKind::AssocFn {
-                    container: ty::AssocItemContainer::ImplContainer,
-                    has_self: impl_item.fn_has_self_parameter,
-                });
-            }
-            ty::AssocKind::Type => {
-                record!(self.tables.kind[def_id] <- EntryKind::AssocType(ty::AssocItemContainer::ImplContainer));
             }
+            ty::AssocKind::Const | ty::AssocKind::Type => {}
         }
-        self.encode_item_type(def_id);
         if let Some(trait_item_def_id) = impl_item.trait_item_def_id {
             self.tables.trait_item_def_id.set(def_id.index, trait_item_def_id.into());
         }
@@ -1358,40 +1334,43 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             return;
         }
 
-        let keys_and_jobs = self
-            .tcx
-            .mir_keys(())
-            .iter()
-            .filter_map(|&def_id| {
-                let (encode_const, encode_opt) = should_encode_mir(self.tcx, def_id);
-                if encode_const || encode_opt {
-                    Some((def_id, encode_const, encode_opt))
-                } else {
-                    None
-                }
-            })
-            .collect::<Vec<_>>();
-        for (def_id, encode_const, encode_opt) in keys_and_jobs.into_iter() {
+        let tcx = self.tcx;
+
+        let keys_and_jobs = tcx.mir_keys(()).iter().filter_map(|&def_id| {
+            let (encode_const, encode_opt) = should_encode_mir(tcx, def_id);
+            if encode_const || encode_opt { Some((def_id, encode_const, encode_opt)) } else { None }
+        });
+        for (def_id, encode_const, encode_opt) in keys_and_jobs {
             debug_assert!(encode_const || encode_opt);
 
             debug!("EntryBuilder::encode_mir({:?})", def_id);
             if encode_opt {
-                record!(self.tables.optimized_mir[def_id.to_def_id()] <- self.tcx.optimized_mir(def_id));
+                record!(self.tables.optimized_mir[def_id.to_def_id()] <- tcx.optimized_mir(def_id));
             }
             if encode_const {
-                record!(self.tables.mir_for_ctfe[def_id.to_def_id()] <- self.tcx.mir_for_ctfe(def_id));
+                record!(self.tables.mir_for_ctfe[def_id.to_def_id()] <- tcx.mir_for_ctfe(def_id));
 
                 // FIXME(generic_const_exprs): this feels wrong to have in `encode_mir`
-                let abstract_const = self.tcx.thir_abstract_const(def_id);
+                let abstract_const = tcx.thir_abstract_const(def_id);
                 if let Ok(Some(abstract_const)) = abstract_const {
                     record!(self.tables.thir_abstract_const[def_id.to_def_id()] <- abstract_const);
                 }
+
+                if should_encode_const(tcx.def_kind(def_id)) {
+                    let qualifs = tcx.mir_const_qualif(def_id);
+                    record!(self.tables.mir_const_qualif[def_id.to_def_id()] <- qualifs);
+                    let body_id = tcx.hir().maybe_body_owned_by(def_id);
+                    if let Some(body_id) = body_id {
+                        let const_data = self.encode_rendered_const_for_body(body_id);
+                        record!(self.tables.rendered_const[def_id.to_def_id()] <- const_data);
+                    }
+                }
             }
-            record!(self.tables.promoted_mir[def_id.to_def_id()] <- self.tcx.promoted_mir(def_id));
+            record!(self.tables.promoted_mir[def_id.to_def_id()] <- tcx.promoted_mir(def_id));
 
             let instance =
                 ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id.to_def_id()));
-            let unused = self.tcx.unused_generic_params(instance);
+            let unused = tcx.unused_generic_params(instance);
             if !unused.is_empty() {
                 record!(self.tables.unused_generic_params[def_id.to_def_id()] <- unused);
             }
@@ -1454,38 +1433,27 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
         debug!("EncodeContext::encode_info_for_item({:?})", def_id);
 
-        let entry_kind = match item.kind {
-            hir::ItemKind::Static(..) => EntryKind::Static,
-            hir::ItemKind::Const(_, body_id) => {
-                let qualifs = self.tcx.at(item.span).mir_const_qualif(def_id);
-                let const_data = self.encode_rendered_const_for_body(body_id);
-                record!(self.tables.mir_const_qualif[def_id] <- qualifs);
-                record!(self.tables.rendered_const[def_id] <- const_data);
-                EntryKind::Const
-            }
+        match item.kind {
             hir::ItemKind::Fn(ref sig, .., body) => {
                 self.tables.asyncness.set(def_id.index, sig.header.asyncness);
                 record_array!(self.tables.fn_arg_names[def_id] <- self.tcx.hir().body_param_names(body));
                 self.tables.constness.set(def_id.index, sig.header.constness);
-                EntryKind::Fn
             }
             hir::ItemKind::Macro(ref macro_def, _) => {
-                EntryKind::MacroDef(self.lazy(&*macro_def.body), macro_def.macro_rules)
+                if macro_def.macro_rules {
+                    self.tables.macro_rules.set(def_id.index, ());
+                }
+                record!(self.tables.macro_definition[def_id] <- &*macro_def.body);
             }
             hir::ItemKind::Mod(ref m) => {
-                return self.encode_info_for_mod(item.def_id, m);
+                return self.encode_info_for_mod(item.def_id.def_id, m);
             }
-            hir::ItemKind::ForeignMod { .. } => EntryKind::ForeignMod,
-            hir::ItemKind::GlobalAsm(..) => EntryKind::GlobalAsm,
-            hir::ItemKind::TyAlias(..) => EntryKind::Type,
             hir::ItemKind::OpaqueTy(..) => {
                 self.encode_explicit_item_bounds(def_id);
-                EntryKind::OpaqueTy
             }
             hir::ItemKind::Enum(..) => {
                 let adt_def = self.tcx.adt_def(def_id);
                 record!(self.tables.repr_options[def_id] <- adt_def.repr());
-                EntryKind::Enum
             }
             hir::ItemKind::Struct(ref struct_def, _) => {
                 let adt_def = self.tcx.adt_def(def_id);
@@ -1500,24 +1468,24 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     .map(|ctor_hir_id| self.tcx.hir().local_def_id(ctor_hir_id).local_def_index);
 
                 let variant = adt_def.non_enum_variant();
-                EntryKind::Struct(self.lazy(VariantData {
+                record!(self.tables.variant_data[def_id] <- VariantData {
                     ctor_kind: variant.ctor_kind,
                     discr: variant.discr,
                     ctor,
                     is_non_exhaustive: variant.is_field_list_non_exhaustive(),
-                }))
+                });
             }
             hir::ItemKind::Union(..) => {
                 let adt_def = self.tcx.adt_def(def_id);
                 record!(self.tables.repr_options[def_id] <- adt_def.repr());
 
                 let variant = adt_def.non_enum_variant();
-                EntryKind::Union(self.lazy(VariantData {
+                record!(self.tables.variant_data[def_id] <- VariantData {
                     ctor_kind: variant.ctor_kind,
                     discr: variant.discr,
                     ctor: None,
                     is_non_exhaustive: variant.is_field_list_non_exhaustive(),
-                }))
+                });
             }
             hir::ItemKind::Impl(hir::Impl { defaultness, constness, .. }) => {
                 self.tables.impl_defaultness.set(def_id.index, *defaultness);
@@ -1543,26 +1511,24 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
                 let polarity = self.tcx.impl_polarity(def_id);
                 self.tables.impl_polarity.set(def_id.index, polarity);
-
-                EntryKind::Impl
             }
             hir::ItemKind::Trait(..) => {
                 let trait_def = self.tcx.trait_def(def_id);
                 record!(self.tables.trait_def[def_id] <- trait_def);
-
-                EntryKind::Trait
             }
             hir::ItemKind::TraitAlias(..) => {
                 let trait_def = self.tcx.trait_def(def_id);
                 record!(self.tables.trait_def[def_id] <- trait_def);
-
-                EntryKind::TraitAlias
             }
             hir::ItemKind::ExternCrate(_) | hir::ItemKind::Use(..) => {
                 bug!("cannot encode info for item {:?}", item)
             }
+            hir::ItemKind::Static(..)
+            | hir::ItemKind::Const(..)
+            | hir::ItemKind::ForeignMod { .. }
+            | hir::ItemKind::GlobalAsm(..)
+            | hir::ItemKind::TyAlias(..) => {}
         };
-        record!(self.tables.kind[def_id] <- entry_kind);
         // FIXME(eddyb) there should be a nicer way to do this.
         match item.kind {
             hir::ItemKind::Enum(..) => record_array!(self.tables.children[def_id] <-
@@ -1590,18 +1556,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             }
             _ => {}
         }
-        match item.kind {
-            hir::ItemKind::Static(..)
-            | hir::ItemKind::Const(..)
-            | hir::ItemKind::Fn(..)
-            | hir::ItemKind::TyAlias(..)
-            | hir::ItemKind::OpaqueTy(..)
-            | hir::ItemKind::Enum(..)
-            | hir::ItemKind::Struct(..)
-            | hir::ItemKind::Union(..)
-            | hir::ItemKind::Impl { .. } => self.encode_item_type(def_id),
-            _ => {}
-        }
         if let hir::ItemKind::Fn(..) = item.kind {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
             if tcx.is_intrinsic(def_id) {
@@ -1613,12 +1567,43 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.impl_trait_ref[def_id] <- trait_ref);
             }
         }
-    }
+        // In some cases, along with the item itself, we also
+        // encode some sub-items. Usually we want some info from the item
+        // so it's easier to do that here then to wait until we would encounter
+        // normally in the visitor walk.
+        match item.kind {
+            hir::ItemKind::Enum(..) => {
+                let def = self.tcx.adt_def(item.def_id.to_def_id());
+                for (i, variant) in def.variants().iter_enumerated() {
+                    self.encode_enum_variant_info(def, i);
 
-    fn encode_info_for_generic_param(&mut self, def_id: DefId, kind: EntryKind, encode_type: bool) {
-        record!(self.tables.kind[def_id] <- kind);
-        if encode_type {
-            self.encode_item_type(def_id);
+                    if let Some(_ctor_def_id) = variant.ctor_def_id {
+                        self.encode_enum_variant_ctor(def, i);
+                    }
+                }
+            }
+            hir::ItemKind::Struct(ref struct_def, _) => {
+                let def = self.tcx.adt_def(item.def_id.to_def_id());
+                // If the struct has a constructor, encode it.
+                if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
+                    let ctor_def_id = self.tcx.hir().local_def_id(ctor_hir_id);
+                    self.encode_struct_ctor(def, ctor_def_id.to_def_id());
+                }
+            }
+            hir::ItemKind::Impl { .. } => {
+                for &trait_item_def_id in
+                    self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
+                {
+                    self.encode_info_for_impl_item(trait_item_def_id);
+                }
+            }
+            hir::ItemKind::Trait(..) => {
+                for &item_def_id in self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
+                {
+                    self.encode_info_for_trait_item(item_def_id);
+                }
+            }
+            _ => {}
         }
     }
 
@@ -1633,34 +1618,16 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             ty::Generator(..) => {
                 let data = self.tcx.generator_kind(def_id).unwrap();
                 let generator_diagnostic_data = typeck_result.get_generator_diagnostic_data();
-                record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::Generator);
                 record!(self.tables.generator_kind[def_id.to_def_id()] <- data);
                 record!(self.tables.generator_diagnostic_data[def_id.to_def_id()]  <- generator_diagnostic_data);
             }
 
-            ty::Closure(..) => {
-                record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::Closure);
+            ty::Closure(_, substs) => {
+                record!(self.tables.fn_sig[def_id.to_def_id()] <- substs.as_closure().sig());
             }
 
             _ => bug!("closure that is neither generator nor closure"),
         }
-        self.encode_item_type(def_id.to_def_id());
-        if let ty::Closure(def_id, substs) = *ty.kind() {
-            record!(self.tables.fn_sig[def_id] <- substs.as_closure().sig());
-        }
-    }
-
-    fn encode_info_for_anon_const(&mut self, id: hir::HirId) {
-        let def_id = self.tcx.hir().local_def_id(id);
-        debug!("EncodeContext::encode_info_for_anon_const({:?})", def_id);
-        let body_id = self.tcx.hir().body_owned_by(def_id);
-        let const_data = self.encode_rendered_const_for_body(body_id);
-        let qualifs = self.tcx.mir_const_qualif(def_id);
-
-        record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::AnonConst);
-        record!(self.tables.mir_const_qualif[def_id.to_def_id()] <- qualifs);
-        record!(self.tables.rendered_const[def_id.to_def_id()] <- const_data);
-        self.encode_item_type(def_id.to_def_id());
     }
 
     fn encode_native_libraries(&mut self) -> LazyArray<NativeLib> {
@@ -1719,7 +1686,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             self.tables.opt_def_kind.set(LOCAL_CRATE.as_def_id().index, DefKind::Mod);
             record!(self.tables.def_span[LOCAL_CRATE.as_def_id()] <- tcx.def_span(LOCAL_CRATE.as_def_id()));
             self.encode_attrs(LOCAL_CRATE.as_def_id().expect_local());
-            record!(self.tables.visibility[LOCAL_CRATE.as_def_id()] <- tcx.visibility(LOCAL_CRATE.as_def_id()));
+            let vis = tcx.local_visibility(CRATE_DEF_ID).map_id(|def_id| def_id.local_def_index);
+            record!(self.tables.visibility[LOCAL_CRATE.as_def_id()] <- vis);
             if let Some(stability) = stability {
                 record!(self.tables.lookup_stability[LOCAL_CRATE.as_def_id()] <- stability);
             }
@@ -1758,7 +1726,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
                 let def_id = id.to_def_id();
                 self.tables.opt_def_kind.set(def_id.index, DefKind::Macro(macro_kind));
-                record!(self.tables.kind[def_id] <- EntryKind::ProcMacro(macro_kind));
+                self.tables.proc_macro.set(def_id.index, macro_kind);
                 self.encode_attrs(id);
                 record!(self.tables.def_keys[def_id] <- def_key);
                 record!(self.tables.def_ident_span[def_id] <- span);
@@ -1872,7 +1840,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
         for id in tcx.hir().items() {
             if matches!(tcx.def_kind(id.def_id), DefKind::Impl) {
-                if let Some(trait_ref) = tcx.impl_trait_ref(id.def_id.to_def_id()) {
+                if let Some(trait_ref) = tcx.impl_trait_ref(id.def_id) {
                     let simplified_self_ty = fast_reject::simplify_type(
                         self.tcx,
                         trait_ref.self_ty(),
@@ -1882,7 +1850,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     fx_hash_map
                         .entry(trait_ref.def_id)
                         .or_default()
-                        .push((id.def_id.local_def_index, simplified_self_ty));
+                        .push((id.def_id.def_id.local_def_index, simplified_self_ty));
                 }
             }
         }
@@ -1996,18 +1964,11 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     hir::Constness::NotConst
                 };
                 self.tables.constness.set(def_id.index, constness);
-                record!(self.tables.kind[def_id] <- EntryKind::ForeignFn);
-            }
-            hir::ForeignItemKind::Static(..) => {
-                record!(self.tables.kind[def_id] <- EntryKind::ForeignStatic);
-            }
-            hir::ForeignItemKind::Type => {
-                record!(self.tables.kind[def_id] <- EntryKind::ForeignType);
+                record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
             }
+            hir::ForeignItemKind::Static(..) | hir::ForeignItemKind::Type => {}
         }
-        self.encode_item_type(def_id);
         if let hir::ForeignItemKind::Fn(..) = nitem.kind {
-            record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
             if tcx.is_intrinsic(def_id) {
                 self.tables.is_intrinsic.set(def_id.index, ());
             }
@@ -2026,17 +1987,12 @@ impl<'a, 'tcx> Visitor<'tcx> for EncodeContext<'a, 'tcx> {
         intravisit::walk_expr(self, ex);
         self.encode_info_for_expr(ex);
     }
-    fn visit_anon_const(&mut self, c: &'tcx AnonConst) {
-        intravisit::walk_anon_const(self, c);
-        self.encode_info_for_anon_const(c.hir_id);
-    }
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
         intravisit::walk_item(self, item);
         match item.kind {
             hir::ItemKind::ExternCrate(_) | hir::ItemKind::Use(..) => {} // ignore these
             _ => self.encode_info_for_item(item.def_id.to_def_id(), item),
         }
-        self.encode_addl_info_for_item(item);
     }
     fn visit_foreign_item(&mut self, ni: &'tcx hir::ForeignItem<'tcx>) {
         intravisit::walk_foreign_item(self, ni);
@@ -2049,29 +2005,13 @@ impl<'a, 'tcx> Visitor<'tcx> for EncodeContext<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
-    fn encode_fields(&mut self, adt_def: ty::AdtDef<'tcx>) {
-        for (variant_index, variant) in adt_def.variants().iter_enumerated() {
-            for (field_index, _field) in variant.fields.iter().enumerate() {
-                self.encode_field(adt_def, variant_index, field_index);
-            }
-        }
-    }
-
     fn encode_info_for_generics(&mut self, generics: &hir::Generics<'tcx>) {
         for param in generics.params {
             let def_id = self.tcx.hir().local_def_id(param.hir_id);
             match param.kind {
-                GenericParamKind::Lifetime { .. } => continue,
-                GenericParamKind::Type { default, .. } => {
-                    self.encode_info_for_generic_param(
-                        def_id.to_def_id(),
-                        EntryKind::TypeParam,
-                        default.is_some(),
-                    );
-                }
-                GenericParamKind::Const { ref default, .. } => {
+                hir::GenericParamKind::Lifetime { .. } | hir::GenericParamKind::Type { .. } => {}
+                hir::GenericParamKind::Const { ref default, .. } => {
                     let def_id = def_id.to_def_id();
-                    self.encode_info_for_generic_param(def_id, EntryKind::ConstParam, true);
                     if default.is_some() {
                         record!(self.tables.const_param_default[def_id] <- self.tcx.const_param_default(def_id))
                     }
@@ -2085,68 +2025,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             self.encode_info_for_closure(expr.hir_id);
         }
     }
-
-    /// In some cases, along with the item itself, we also
-    /// encode some sub-items. Usually we want some info from the item
-    /// so it's easier to do that here then to wait until we would encounter
-    /// normally in the visitor walk.
-    fn encode_addl_info_for_item(&mut self, item: &hir::Item<'_>) {
-        match item.kind {
-            hir::ItemKind::Static(..)
-            | hir::ItemKind::Const(..)
-            | hir::ItemKind::Fn(..)
-            | hir::ItemKind::Macro(..)
-            | hir::ItemKind::Mod(..)
-            | hir::ItemKind::ForeignMod { .. }
-            | hir::ItemKind::GlobalAsm(..)
-            | hir::ItemKind::ExternCrate(..)
-            | hir::ItemKind::Use(..)
-            | hir::ItemKind::TyAlias(..)
-            | hir::ItemKind::OpaqueTy(..)
-            | hir::ItemKind::TraitAlias(..) => {
-                // no sub-item recording needed in these cases
-            }
-            hir::ItemKind::Enum(..) => {
-                let def = self.tcx.adt_def(item.def_id.to_def_id());
-                self.encode_fields(def);
-
-                for (i, variant) in def.variants().iter_enumerated() {
-                    self.encode_enum_variant_info(def, i);
-
-                    if let Some(_ctor_def_id) = variant.ctor_def_id {
-                        self.encode_enum_variant_ctor(def, i);
-                    }
-                }
-            }
-            hir::ItemKind::Struct(ref struct_def, _) => {
-                let def = self.tcx.adt_def(item.def_id.to_def_id());
-                self.encode_fields(def);
-
-                // If the struct has a constructor, encode it.
-                if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
-                    let ctor_def_id = self.tcx.hir().local_def_id(ctor_hir_id);
-                    self.encode_struct_ctor(def, ctor_def_id.to_def_id());
-                }
-            }
-            hir::ItemKind::Union(..) => {
-                let def = self.tcx.adt_def(item.def_id.to_def_id());
-                self.encode_fields(def);
-            }
-            hir::ItemKind::Impl { .. } => {
-                for &trait_item_def_id in
-                    self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
-                {
-                    self.encode_info_for_impl_item(trait_item_def_id);
-                }
-            }
-            hir::ItemKind::Trait(..) => {
-                for &item_def_id in self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
-                {
-                    self.encode_info_for_trait_item(item_def_id);
-                }
-            }
-        }
-    }
 }
 
 /// Used to prefetch queries which will be needed later by metadata encoding.
@@ -2269,7 +2147,7 @@ pub fn encode_metadata(tcx: TyCtxt<'_>, path: &Path) {
 
 fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
     let mut encoder = opaque::FileEncoder::new(path)
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to create file encoder: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailCreateFileEncoder { err }));
     encoder.emit_raw_bytes(METADATA_HEADER);
 
     // Will be filled with the root position after encoding everything.
@@ -2314,10 +2192,10 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
     // Encode the root position.
     let header = METADATA_HEADER.len();
     file.seek(std::io::SeekFrom::Start(header as u64))
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to seek the file: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailSeekFile { err }));
     let pos = root.position.get();
     file.write_all(&[(pos >> 24) as u8, (pos >> 16) as u8, (pos >> 8) as u8, (pos >> 0) as u8])
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to write to the file: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailWriteFile { err }));
 
     // Return to the position where we are before writing the root position.
     file.seek(std::io::SeekFrom::Start(pos_before_seek)).unwrap();
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index aeffc85b5075..748b3afec37c 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -334,12 +334,11 @@ macro_rules! define_tables {
 }
 
 define_tables! {
-    kind: Table<DefIndex, LazyValue<EntryKind>>,
     attributes: Table<DefIndex, LazyArray<ast::Attribute>>,
     children: Table<DefIndex, LazyArray<DefIndex>>,
 
     opt_def_kind: Table<DefIndex, DefKind>,
-    visibility: Table<DefIndex, LazyValue<ty::Visibility>>,
+    visibility: Table<DefIndex, LazyValue<ty::Visibility<DefIndex>>>,
     def_span: Table<DefIndex, LazyValue<Span>>,
     def_ident_span: Table<DefIndex, LazyValue<Span>>,
     lookup_stability: Table<DefIndex, LazyValue<attr::Stability>>,
@@ -393,39 +392,13 @@ define_tables! {
     proc_macro_quoted_spans: Table<usize, LazyValue<Span>>,
     generator_diagnostic_data: Table<DefIndex, LazyValue<GeneratorDiagnosticData<'static>>>,
     may_have_doc_links: Table<DefIndex, ()>,
-}
-
-#[derive(Copy, Clone, MetadataEncodable, MetadataDecodable)]
-enum EntryKind {
-    AnonConst,
-    Const,
-    Static,
-    ForeignStatic,
-    ForeignMod,
-    ForeignType,
-    GlobalAsm,
-    Type,
-    TypeParam,
-    ConstParam,
-    OpaqueTy,
-    Enum,
-    Field,
-    Variant(LazyValue<VariantData>),
-    Struct(LazyValue<VariantData>),
-    Union(LazyValue<VariantData>),
-    Fn,
-    ForeignFn,
-    Mod(LazyArray<ModChild>),
-    MacroDef(LazyValue<ast::MacArgs>, /*macro_rules*/ bool),
-    ProcMacro(MacroKind),
-    Closure,
-    Generator,
-    Trait,
-    Impl,
-    AssocFn { container: ty::AssocItemContainer, has_self: bool },
-    AssocType(ty::AssocItemContainer),
-    AssocConst(ty::AssocItemContainer),
-    TraitAlias,
+    variant_data: Table<DefIndex, LazyValue<VariantData>>,
+    assoc_container: Table<DefIndex, ty::AssocItemContainer>,
+    // Slot is full when macro is macro_rules.
+    macro_rules: Table<DefIndex, ()>,
+    macro_definition: Table<DefIndex, LazyValue<ast::MacArgs>>,
+    proc_macro: Table<DefIndex, MacroKind>,
+    module_reexports: Table<DefIndex, LazyArray<ModChild>>,
 }
 
 #[derive(TyEncodable, TyDecodable)]
@@ -459,7 +432,6 @@ pub fn provide(providers: &mut Providers) {
 
 trivially_parameterized_over_tcx! {
     VariantData,
-    EntryKind,
     RawDefId,
     TraitImpls,
     IncoherentImpls,
diff --git a/compiler/rustc_metadata/src/rmeta/table.rs b/compiler/rustc_metadata/src/rmeta/table.rs
index 21841ae2532a..e7c1abd126e0 100644
--- a/compiler/rustc_metadata/src/rmeta/table.rs
+++ b/compiler/rustc_metadata/src/rmeta/table.rs
@@ -10,7 +10,6 @@ use rustc_span::hygiene::MacroKind;
 use std::convert::TryInto;
 use std::marker::PhantomData;
 use std::num::NonZeroUsize;
-use tracing::debug;
 
 /// Helper trait, for encoding to, and decoding from, a fixed number of bytes.
 /// Used mainly for Lazy positions and lengths.
@@ -51,7 +50,7 @@ macro_rules! fixed_size_enum {
                 }
                 match b[0] - 1 {
                     $(${index()} => Some($($pat)*),)*
-                    _ => panic!("Unexpected ImplPolarity code: {:?}", b[0]),
+                    _ => panic!("Unexpected {} code: {:?}", stringify!($ty), b[0]),
                 }
             }
 
@@ -91,6 +90,7 @@ fixed_size_enum! {
         ( AnonConst                                )
         ( InlineConst                              )
         ( OpaqueTy                                 )
+        ( ImplTraitPlaceholder                     )
         ( Field                                    )
         ( LifetimeParam                            )
         ( GlobalAsm                                )
@@ -141,6 +141,21 @@ fixed_size_enum! {
     }
 }
 
+fixed_size_enum! {
+    ty::AssocItemContainer {
+        ( TraitContainer )
+        ( ImplContainer  )
+    }
+}
+
+fixed_size_enum! {
+    MacroKind {
+        ( Attr   )
+        ( Bang   )
+        ( Derive )
+    }
+}
+
 // We directly encode `DefPathHash` because a `LazyValue` would incur a 25% cost.
 impl FixedSizeEncoding for Option<DefPathHash> {
     type ByteArray = [u8; 16];
diff --git a/compiler/rustc_middle/Cargo.toml b/compiler/rustc_middle/Cargo.toml
index 008d2c7091c1..cca17a4eccd3 100644
--- a/compiler/rustc_middle/Cargo.toml
+++ b/compiler/rustc_middle/Cargo.toml
@@ -7,34 +7,35 @@ edition = "2021"
 doctest = false
 
 [dependencies]
-rustc_arena = { path = "../rustc_arena" }
 bitflags = "1.2.1"
+chalk-ir = "0.80.0"
 either = "1.5.0"
 gsgdt = "0.1.2"
-tracing = "0.1"
-rustc-rayon = { version = "0.4.0", optional = true }
-rustc-rayon-core = { version = "0.4.0", optional = true }
 polonius-engine = "0.13.0"
-rustc_apfloat = { path = "../rustc_apfloat" }
-rustc_attr = { path = "../rustc_attr" }
-rustc_feature = { path = "../rustc_feature" }
-rustc_hir = { path = "../rustc_hir" }
-rustc_target = { path = "../rustc_target" }
-rustc_macros = { path = "../rustc_macros" }
-rustc_data_structures = { path = "../rustc_data_structures" }
-rustc_query_system = { path = "../rustc_query_system" }
-rustc_errors = { path = "../rustc_errors" }
-rustc_graphviz = { path = "../rustc_graphviz" }
-rustc_index = { path = "../rustc_index" }
-rustc_serialize = { path = "../rustc_serialize" }
-rustc_ast = { path = "../rustc_ast" }
-rustc_span = { path = "../rustc_span" }
-chalk-ir = "0.80.0"
-smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
-rustc_session = { path = "../rustc_session" }
-rustc_type_ir = { path = "../rustc_type_ir" }
 rand = "0.8.4"
 rand_xoshiro = "0.6.0"
+rustc_apfloat = { path = "../rustc_apfloat" }
+rustc_arena = { path = "../rustc_arena" }
+rustc_ast = { path = "../rustc_ast" }
+rustc_attr = { path = "../rustc_attr" }
+rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_errors = { path = "../rustc_errors" }
+rustc_feature = { path = "../rustc_feature" }
+rustc_graphviz = { path = "../rustc_graphviz" }
+rustc_hir = { path = "../rustc_hir" }
+rustc_index = { path = "../rustc_index" }
+rustc_macros = { path = "../rustc_macros" }
+rustc_query_system = { path = "../rustc_query_system" }
+rustc-rayon-core = { version = "0.4.0", optional = true }
+rustc-rayon = { version = "0.4.0", optional = true }
+rustc_serialize = { path = "../rustc_serialize" }
+rustc_session = { path = "../rustc_session" }
+rustc_span = { path = "../rustc_span" }
+rustc_target = { path = "../rustc_target" }
+rustc_type_ir = { path = "../rustc_type_ir" }
+smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+thin-vec = "0.2.8"
+tracing = "0.1"
 
 [features]
 rustc_use_parallel_compiler = ["rustc-rayon", "rustc-rayon-core"]
diff --git a/compiler/rustc_middle/benches/lib.rs b/compiler/rustc_middle/benches/lib.rs
deleted file mode 100644
index 237751bcbd78..000000000000
--- a/compiler/rustc_middle/benches/lib.rs
+++ /dev/null
@@ -1,54 +0,0 @@
-#![feature(test)]
-
-extern crate test;
-
-use test::Bencher;
-
-// Static/dynamic method dispatch
-
-struct Struct {
-    field: isize,
-}
-
-trait Trait {
-    fn method(&self) -> isize;
-}
-
-impl Trait for Struct {
-    fn method(&self) -> isize {
-        self.field
-    }
-}
-
-#[bench]
-fn trait_vtable_method_call(b: &mut Bencher) {
-    let s = Struct { field: 10 };
-    let t = &s as &dyn Trait;
-    b.iter(|| t.method());
-}
-
-#[bench]
-fn trait_static_method_call(b: &mut Bencher) {
-    let s = Struct { field: 10 };
-    b.iter(|| s.method());
-}
-
-// Overhead of various match forms
-
-#[bench]
-fn option_some(b: &mut Bencher) {
-    let x = Some(10);
-    b.iter(|| match x {
-        Some(y) => y,
-        None => 11,
-    });
-}
-
-#[bench]
-fn vec_pattern(b: &mut Bencher) {
-    let x = [1, 2, 3, 4, 5, 6];
-    b.iter(|| match x {
-        [1, 2, 3, ..] => 10,
-        _ => 11,
-    });
-}
diff --git a/compiler/rustc_middle/src/arena.rs b/compiler/rustc_middle/src/arena.rs
index b94de537dc81..6bdf5a023b6c 100644
--- a/compiler/rustc_middle/src/arena.rs
+++ b/compiler/rustc_middle/src/arena.rs
@@ -100,7 +100,9 @@ macro_rules! arena_types {
             [decode] is_late_bound_map: rustc_data_structures::fx::FxIndexSet<rustc_hir::def_id::LocalDefId>,
             [decode] impl_source: rustc_middle::traits::ImplSource<'tcx, ()>,
 
-            [] dep_kind: rustc_middle::dep_graph::DepKindStruct,
+            [] dep_kind: rustc_middle::dep_graph::DepKindStruct<'tcx>,
+
+            [decode] trait_impl_trait_tys: rustc_data_structures::fx::FxHashMap<rustc_hir::def_id::DefId, rustc_middle::ty::Ty<'tcx>>,
         ]);
     )
 }
diff --git a/compiler/rustc_middle/src/dep_graph/dep_node.rs b/compiler/rustc_middle/src/dep_graph/dep_node.rs
index 65fc8a2e9cf5..40b9d73db94c 100644
--- a/compiler/rustc_middle/src/dep_graph/dep_node.rs
+++ b/compiler/rustc_middle/src/dep_graph/dep_node.rs
@@ -62,93 +62,18 @@ use crate::ty::TyCtxt;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_hir::definitions::DefPathHash;
-use rustc_hir::HirId;
+use rustc_hir::{HirId, OwnerId};
 use rustc_query_system::dep_graph::FingerprintStyle;
 use rustc_span::symbol::Symbol;
 use std::hash::Hash;
 
 pub use rustc_query_system::dep_graph::{DepContext, DepNodeParams};
 
-/// This struct stores metadata about each DepKind.
-///
-/// Information is retrieved by indexing the `DEP_KINDS` array using the integer value
-/// of the `DepKind`. Overall, this allows to implement `DepContext` using this manual
-/// jump table instead of large matches.
-pub struct DepKindStruct {
-    /// Anonymous queries cannot be replayed from one compiler invocation to the next.
-    /// When their result is needed, it is recomputed. They are useful for fine-grained
-    /// dependency tracking, and caching within one compiler invocation.
-    pub is_anon: bool,
-
-    /// Eval-always queries do not track their dependencies, and are always recomputed, even if
-    /// their inputs have not changed since the last compiler invocation. The result is still
-    /// cached within one compiler invocation.
-    pub is_eval_always: bool,
-
-    /// Whether the query key can be recovered from the hashed fingerprint.
-    /// See [DepNodeParams] trait for the behaviour of each key type.
-    pub fingerprint_style: FingerprintStyle,
-
-    /// The red/green evaluation system will try to mark a specific DepNode in the
-    /// dependency graph as green by recursively trying to mark the dependencies of
-    /// that `DepNode` as green. While doing so, it will sometimes encounter a `DepNode`
-    /// where we don't know if it is red or green and we therefore actually have
-    /// to recompute its value in order to find out. Since the only piece of
-    /// information that we have at that point is the `DepNode` we are trying to
-    /// re-evaluate, we need some way to re-run a query from just that. This is what
-    /// `force_from_dep_node()` implements.
-    ///
-    /// In the general case, a `DepNode` consists of a `DepKind` and an opaque
-    /// GUID/fingerprint that will uniquely identify the node. This GUID/fingerprint
-    /// is usually constructed by computing a stable hash of the query-key that the
-    /// `DepNode` corresponds to. Consequently, it is not in general possible to go
-    /// back from hash to query-key (since hash functions are not reversible). For
-    /// this reason `force_from_dep_node()` is expected to fail from time to time
-    /// because we just cannot find out, from the `DepNode` alone, what the
-    /// corresponding query-key is and therefore cannot re-run the query.
-    ///
-    /// The system deals with this case letting `try_mark_green` fail which forces
-    /// the root query to be re-evaluated.
-    ///
-    /// Now, if `force_from_dep_node()` would always fail, it would be pretty useless.
-    /// Fortunately, we can use some contextual information that will allow us to
-    /// reconstruct query-keys for certain kinds of `DepNode`s. In particular, we
-    /// enforce by construction that the GUID/fingerprint of certain `DepNode`s is a
-    /// valid `DefPathHash`. Since we also always build a huge table that maps every
-    /// `DefPathHash` in the current codebase to the corresponding `DefId`, we have
-    /// everything we need to re-run the query.
-    ///
-    /// Take the `mir_promoted` query as an example. Like many other queries, it
-    /// just has a single parameter: the `DefId` of the item it will compute the
-    /// validated MIR for. Now, when we call `force_from_dep_node()` on a `DepNode`
-    /// with kind `MirValidated`, we know that the GUID/fingerprint of the `DepNode`
-    /// is actually a `DefPathHash`, and can therefore just look up the corresponding
-    /// `DefId` in `tcx.def_path_hash_to_def_id`.
-    pub force_from_dep_node: Option<fn(tcx: TyCtxt<'_>, dep_node: DepNode) -> bool>,
-
-    /// Invoke a query to put the on-disk cached value in memory.
-    pub try_load_from_on_disk_cache: Option<fn(TyCtxt<'_>, DepNode)>,
-}
-
-impl DepKind {
-    #[inline(always)]
-    pub fn fingerprint_style(self, tcx: TyCtxt<'_>) -> FingerprintStyle {
-        // Only fetch the DepKindStruct once.
-        let data = tcx.query_kind(self);
-        if data.is_anon {
-            return FingerprintStyle::Opaque;
-        }
-        data.fingerprint_style
-    }
-}
-
 macro_rules! define_dep_nodes {
     (
-    $(
-        [$($attrs:tt)*]
-        $variant:ident $(( $tuple_arg_ty:ty $(,)? ))*
-      ,)*
-    ) => (
+     $($(#[$attr:meta])*
+        [$($modifiers:tt)*] fn $variant:ident($($K:tt)*) -> $V:ty,)*) => {
+
         #[macro_export]
         macro_rules! make_dep_kind_array {
             ($mod:ident) => {[ $($mod::$variant()),* ]};
@@ -158,10 +83,10 @@ macro_rules! define_dep_nodes {
         #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Encodable, Decodable)]
         #[allow(non_camel_case_types)]
         pub enum DepKind {
-            $($variant),*
+            $( $( #[$attr] )* $variant),*
         }
 
-        fn dep_kind_from_label_string(label: &str) -> Result<DepKind, ()> {
+        pub(super) fn dep_kind_from_label_string(label: &str) -> Result<DepKind, ()> {
             match label {
                 $(stringify!($variant) => Ok(DepKind::$variant),)*
                 _ => Err(()),
@@ -176,24 +101,17 @@ macro_rules! define_dep_nodes {
                 pub const $variant: &str = stringify!($variant);
             )*
         }
-    );
+    };
 }
 
-rustc_dep_node_append!(define_dep_nodes![
-    // We use this for most things when incr. comp. is turned off.
-    [] Null,
-
-    // We use this to create a forever-red node.
-    [] Red,
-
-    [anon] TraitSelect,
-
-    // WARNING: if `Symbol` is changed, make sure you update `make_compile_codegen_unit` below.
-    [] CompileCodegenUnit(Symbol),
-
-    // WARNING: if `MonoItem` is changed, make sure you update `make_compile_mono_item` below.
-    // Only used by rustc_codegen_cranelift
-    [] CompileMonoItem(MonoItem),
+rustc_query_append!(define_dep_nodes![
+    /// We use this for most things when incr. comp. is turned off.
+    [] fn Null() -> (),
+    /// We use this to create a forever-red node.
+    [] fn Red() -> (),
+    [] fn TraitSelect() -> (),
+    [] fn CompileCodegenUnit() -> (),
+    [] fn CompileMonoItem() -> (),
 ]);
 
 // WARNING: `construct` is generic and does not know that `CompileCodegenUnit` takes `Symbol`s as keys.
@@ -223,11 +141,6 @@ static_assert_size!(DepNode, 18);
 static_assert_size!(DepNode, 24);
 
 pub trait DepNodeExt: Sized {
-    /// Construct a DepNode from the given DepKind and DefPathHash. This
-    /// method will assert that the given DepKind actually requires a
-    /// single DefId/DefPathHash parameter.
-    fn from_def_path_hash(tcx: TyCtxt<'_>, def_path_hash: DefPathHash, kind: DepKind) -> Self;
-
     /// Extracts the DefId corresponding to this DepNode. This will work
     /// if two conditions are met:
     ///
@@ -252,14 +165,6 @@ pub trait DepNodeExt: Sized {
 }
 
 impl DepNodeExt for DepNode {
-    /// Construct a DepNode from the given DepKind and DefPathHash. This
-    /// method will assert that the given DepKind actually requires a
-    /// single DefId/DefPathHash parameter.
-    fn from_def_path_hash(tcx: TyCtxt<'_>, def_path_hash: DefPathHash, kind: DepKind) -> DepNode {
-        debug_assert!(kind.fingerprint_style(tcx) == FingerprintStyle::DefPathHash);
-        DepNode { kind, hash: def_path_hash.0.into() }
-    }
-
     /// Extracts the DefId corresponding to this DepNode. This will work
     /// if two conditions are met:
     ///
@@ -271,7 +176,7 @@ impl DepNodeExt for DepNode {
     /// refers to something from the previous compilation session that
     /// has been removed.
     fn extract_def_id<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Option<DefId> {
-        if self.kind.fingerprint_style(tcx) == FingerprintStyle::DefPathHash {
+        if tcx.fingerprint_style(self.kind) == FingerprintStyle::DefPathHash {
             Some(tcx.def_path_hash_to_def_id(DefPathHash(self.hash.into()), &mut || {
                 panic!("Failed to extract DefId: {:?} {}", self.kind, self.hash)
             }))
@@ -288,7 +193,7 @@ impl DepNodeExt for DepNode {
     ) -> Result<DepNode, ()> {
         let kind = dep_kind_from_label_string(label)?;
 
-        match kind.fingerprint_style(tcx) {
+        match tcx.fingerprint_style(kind) {
             FingerprintStyle::Opaque => Err(()),
             FingerprintStyle::Unit => Ok(DepNode::new_no_params(tcx, kind)),
             FingerprintStyle::DefPathHash => {
@@ -364,6 +269,28 @@ impl<'tcx> DepNodeParams<TyCtxt<'tcx>> for LocalDefId {
     }
 }
 
+impl<'tcx> DepNodeParams<TyCtxt<'tcx>> for OwnerId {
+    #[inline(always)]
+    fn fingerprint_style() -> FingerprintStyle {
+        FingerprintStyle::DefPathHash
+    }
+
+    #[inline(always)]
+    fn to_fingerprint(&self, tcx: TyCtxt<'tcx>) -> Fingerprint {
+        self.to_def_id().to_fingerprint(tcx)
+    }
+
+    #[inline(always)]
+    fn to_debug_str(&self, tcx: TyCtxt<'tcx>) -> String {
+        self.to_def_id().to_debug_str(tcx)
+    }
+
+    #[inline(always)]
+    fn recover(tcx: TyCtxt<'tcx>, dep_node: &DepNode) -> Option<Self> {
+        dep_node.extract_def_id(tcx).map(|id| OwnerId { def_id: id.expect_local() })
+    }
+}
+
 impl<'tcx> DepNodeParams<TyCtxt<'tcx>> for CrateNum {
     #[inline(always)]
     fn fingerprint_style() -> FingerprintStyle {
diff --git a/compiler/rustc_middle/src/dep_graph/mod.rs b/compiler/rustc_middle/src/dep_graph/mod.rs
index c8b3b52b0fb2..2e62bebc8525 100644
--- a/compiler/rustc_middle/src/dep_graph/mod.rs
+++ b/compiler/rustc_middle/src/dep_graph/mod.rs
@@ -11,15 +11,17 @@ pub use rustc_query_system::dep_graph::{
     SerializedDepNodeIndex, WorkProduct, WorkProductId,
 };
 
-pub use dep_node::{label_strs, DepKind, DepKindStruct, DepNode, DepNodeExt};
+pub use dep_node::{label_strs, DepKind, DepNode, DepNodeExt};
 pub(crate) use dep_node::{make_compile_codegen_unit, make_compile_mono_item};
 
 pub type DepGraph = rustc_query_system::dep_graph::DepGraph<DepKind>;
+
 pub type TaskDeps = rustc_query_system::dep_graph::TaskDeps<DepKind>;
 pub type TaskDepsRef<'a> = rustc_query_system::dep_graph::TaskDepsRef<'a, DepKind>;
 pub type DepGraphQuery = rustc_query_system::dep_graph::DepGraphQuery<DepKind>;
 pub type SerializedDepGraph = rustc_query_system::dep_graph::SerializedDepGraph<DepKind>;
 pub type EdgeFilter = rustc_query_system::dep_graph::debug::EdgeFilter<DepKind>;
+pub type DepKindStruct<'tcx> = rustc_query_system::dep_graph::DepKindStruct<TyCtxt<'tcx>>;
 
 impl rustc_query_system::dep_graph::DepKind for DepKind {
     const NULL: Self = DepKind::Null;
@@ -91,50 +93,8 @@ impl<'tcx> DepContext for TyCtxt<'tcx> {
         self.sess
     }
 
-    #[inline(always)]
-    fn fingerprint_style(&self, kind: DepKind) -> rustc_query_system::dep_graph::FingerprintStyle {
-        kind.fingerprint_style(*self)
-    }
-
-    #[inline(always)]
-    fn is_eval_always(&self, kind: DepKind) -> bool {
-        self.query_kind(kind).is_eval_always
-    }
-
-    fn try_force_from_dep_node(&self, dep_node: DepNode) -> bool {
-        debug!("try_force_from_dep_node({:?}) --- trying to force", dep_node);
-
-        // We must avoid ever having to call `force_from_dep_node()` for a
-        // `DepNode::codegen_unit`:
-        // Since we cannot reconstruct the query key of a `DepNode::codegen_unit`, we
-        // would always end up having to evaluate the first caller of the
-        // `codegen_unit` query that *is* reconstructible. This might very well be
-        // the `compile_codegen_unit` query, thus re-codegenning the whole CGU just
-        // to re-trigger calling the `codegen_unit` query with the right key. At
-        // that point we would already have re-done all the work we are trying to
-        // avoid doing in the first place.
-        // The solution is simple: Just explicitly call the `codegen_unit` query for
-        // each CGU, right after partitioning. This way `try_mark_green` will always
-        // hit the cache instead of having to go through `force_from_dep_node`.
-        // This assertion makes sure, we actually keep applying the solution above.
-        debug_assert!(
-            dep_node.kind != DepKind::codegen_unit,
-            "calling force_from_dep_node() on DepKind::codegen_unit"
-        );
-
-        let cb = self.query_kind(dep_node.kind);
-        if let Some(f) = cb.force_from_dep_node {
-            f(*self, dep_node);
-            true
-        } else {
-            false
-        }
-    }
-
-    fn try_load_from_on_disk_cache(&self, dep_node: DepNode) {
-        let cb = self.query_kind(dep_node.kind);
-        if let Some(f) = cb.try_load_from_on_disk_cache {
-            f(*self, dep_node)
-        }
+    #[inline]
+    fn dep_kind_info(&self, dep_kind: DepKind) -> &DepKindStruct<'tcx> {
+        &self.query_kinds[dep_kind as usize]
     }
 }
diff --git a/compiler/rustc_middle/src/error.rs b/compiler/rustc_middle/src/error.rs
new file mode 100644
index 000000000000..a4ceb494569b
--- /dev/null
+++ b/compiler/rustc_middle/src/error.rs
@@ -0,0 +1,50 @@
+use rustc_macros::Diagnostic;
+use rustc_span::Span;
+
+use crate::ty::Ty;
+
+#[derive(Diagnostic)]
+#[diag(middle::drop_check_overflow, code = "E0320")]
+#[note]
+pub struct DropCheckOverflow<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub ty: Ty<'tcx>,
+    pub overflow_ty: Ty<'tcx>,
+}
+
+#[derive(Diagnostic)]
+#[diag(middle::opaque_hidden_type_mismatch)]
+pub struct OpaqueHiddenTypeMismatch<'tcx> {
+    pub self_ty: Ty<'tcx>,
+    pub other_ty: Ty<'tcx>,
+    #[primary_span]
+    #[label]
+    pub other_span: Span,
+    #[subdiagnostic]
+    pub sub: TypeMismatchReason,
+}
+
+#[derive(Subdiagnostic)]
+pub enum TypeMismatchReason {
+    #[label(middle::conflict_types)]
+    ConflictType {
+        #[primary_span]
+        span: Span,
+    },
+    #[note(middle::previous_use_here)]
+    PreviousUse {
+        #[primary_span]
+        span: Span,
+    },
+}
+
+#[derive(Diagnostic)]
+#[diag(middle::limit_invalid)]
+pub struct LimitInvalid<'a> {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub value_span: Span,
+    pub error_str: &'a str,
+}
diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 8f7877392483..b5f7b26ea7ab 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -93,7 +93,7 @@ pub struct ParentOwnerIterator<'hir> {
 }
 
 impl<'hir> Iterator for ParentOwnerIterator<'hir> {
-    type Item = (LocalDefId, OwnerNode<'hir>);
+    type Item = (OwnerId, OwnerNode<'hir>);
 
     fn next(&mut self) -> Option<Self::Item> {
         if self.current_id.local_id.index() != 0 {
@@ -107,13 +107,13 @@ impl<'hir> Iterator for ParentOwnerIterator<'hir> {
         }
         loop {
             // There are nodes that do not have entries, so we need to skip them.
-            let parent_id = self.map.def_key(self.current_id.owner).parent;
+            let parent_id = self.map.def_key(self.current_id.owner.def_id).parent;
 
-            let parent_id = parent_id.map_or(CRATE_HIR_ID.owner, |local_def_index| {
+            let parent_id = parent_id.map_or(CRATE_OWNER_ID, |local_def_index| {
                 let def_id = LocalDefId { local_def_index };
                 self.map.local_def_id_to_hir_id(def_id).owner
             });
-            self.current_id = HirId::make_owner(parent_id);
+            self.current_id = HirId::make_owner(parent_id.def_id);
 
             // If this `HirId` doesn't have an entry, skip it and look for its `parent_id`.
             if let Some(node) = self.map.tcx.hir_owner(self.current_id.owner) {
@@ -131,7 +131,7 @@ impl<'hir> Map<'hir> {
 
     #[inline]
     pub fn root_module(self) -> &'hir Mod<'hir> {
-        match self.tcx.hir_owner(CRATE_DEF_ID).map(|o| o.node) {
+        match self.tcx.hir_owner(CRATE_OWNER_ID).map(|o| o.node) {
             Some(OwnerNode::Crate(item)) => item,
             _ => bug!(),
         }
@@ -186,7 +186,7 @@ impl<'hir> Map<'hir> {
     #[inline]
     pub fn opt_local_def_id(self, hir_id: HirId) -> Option<LocalDefId> {
         if hir_id.local_id == ItemLocalId::new(0) {
-            Some(hir_id.owner)
+            Some(hir_id.owner.def_id)
         } else {
             self.tcx
                 .hir_owner_nodes(hir_id.owner)
@@ -212,7 +212,13 @@ impl<'hir> Map<'hir> {
                 ItemKind::Fn(..) => DefKind::Fn,
                 ItemKind::Macro(_, macro_kind) => DefKind::Macro(macro_kind),
                 ItemKind::Mod(..) => DefKind::Mod,
-                ItemKind::OpaqueTy(..) => DefKind::OpaqueTy,
+                ItemKind::OpaqueTy(ref opaque) => {
+                    if opaque.in_trait {
+                        DefKind::ImplTraitPlaceholder
+                    } else {
+                        DefKind::OpaqueTy
+                    }
+                }
                 ItemKind::TyAlias(..) => DefKind::TyAlias,
                 ItemKind::Enum(..) => DefKind::Enum,
                 ItemKind::Struct(..) => DefKind::Struct,
@@ -291,6 +297,9 @@ impl<'hir> Map<'hir> {
         Some(def_kind)
     }
 
+    /// Finds the id of the parent node to this one.
+    ///
+    /// If calling repeatedly and iterating over parents, prefer [`Map::parent_iter`].
     pub fn find_parent_node(self, id: HirId) -> Option<HirId> {
         if id.local_id == ItemLocalId::from_u32(0) {
             Some(self.tcx.hir_owner_parent(id.owner))
@@ -298,6 +307,8 @@ impl<'hir> Map<'hir> {
             let owner = self.tcx.hir_owner_nodes(id.owner).as_owner()?;
             let node = owner.nodes[id.local_id].as_ref()?;
             let hir_id = HirId { owner: id.owner, local_id: node.parent };
+            // HIR indexing should have checked that.
+            debug_assert_ne!(id.local_id, node.parent);
             Some(hir_id)
         }
     }
@@ -341,7 +352,7 @@ impl<'hir> Map<'hir> {
     }
 
     pub fn get_generics(self, id: LocalDefId) -> Option<&'hir Generics<'hir>> {
-        let node = self.tcx.hir_owner(id)?;
+        let node = self.tcx.hir_owner(OwnerId { def_id: id })?;
         node.node.generics()
     }
 
@@ -521,7 +532,7 @@ impl<'hir> Map<'hir> {
 
     pub fn get_module(self, module: LocalDefId) -> (&'hir Mod<'hir>, Span, HirId) {
         let hir_id = HirId::make_owner(module);
-        match self.tcx.hir_owner(module).map(|o| o.node) {
+        match self.tcx.hir_owner(hir_id.owner).map(|o| o.node) {
             Some(OwnerNode::Item(&Item { span, kind: ItemKind::Mod(ref m), .. })) => {
                 (m, span, hir_id)
             }
@@ -611,14 +622,14 @@ impl<'hir> Map<'hir> {
     pub fn for_each_module(self, mut f: impl FnMut(LocalDefId)) {
         let crate_items = self.tcx.hir_crate_items(());
         for module in crate_items.submodules.iter() {
-            f(*module)
+            f(module.def_id)
         }
     }
 
     #[inline]
     pub fn par_for_each_module(self, f: impl Fn(LocalDefId) + Sync + Send) {
         let crate_items = self.tcx.hir_crate_items(());
-        par_for_each_in(&crate_items.submodules[..], |module| f(*module))
+        par_for_each_in(&crate_items.submodules[..], |module| f(module.def_id))
     }
 
     /// Returns an iterator for the nodes in the ancestor tree of the `current_id`
@@ -710,27 +721,27 @@ impl<'hir> Map<'hir> {
         None
     }
 
-    /// Retrieves the `HirId` for `id`'s parent item, or `id` itself if no
+    /// Retrieves the `OwnerId` for `id`'s parent item, or `id` itself if no
     /// parent item is in this map. The "parent item" is the closest parent node
     /// in the HIR which is recorded by the map and is an item, either an item
     /// in a module, trait, or impl.
-    pub fn get_parent_item(self, hir_id: HirId) -> LocalDefId {
+    pub fn get_parent_item(self, hir_id: HirId) -> OwnerId {
         if let Some((def_id, _node)) = self.parent_owner_iter(hir_id).next() {
             def_id
         } else {
-            CRATE_DEF_ID
+            CRATE_OWNER_ID
         }
     }
 
-    /// Returns the `HirId` of `id`'s nearest module parent, or `id` itself if no
+    /// Returns the `OwnerId` of `id`'s nearest module parent, or `id` itself if no
     /// module parent is in this map.
-    pub(super) fn get_module_parent_node(self, hir_id: HirId) -> LocalDefId {
+    pub(super) fn get_module_parent_node(self, hir_id: HirId) -> OwnerId {
         for (def_id, node) in self.parent_owner_iter(hir_id) {
             if let OwnerNode::Item(&Item { kind: ItemKind::Mod(_), .. }) = node {
                 return def_id;
             }
         }
-        CRATE_DEF_ID
+        CRATE_OWNER_ID
     }
 
     /// When on an if expression, a match arm tail expression or a match arm, give back
@@ -803,30 +814,30 @@ impl<'hir> Map<'hir> {
         }
         bug!(
             "expected foreign mod or inlined parent, found {}",
-            self.node_to_string(HirId::make_owner(parent))
+            self.node_to_string(HirId::make_owner(parent.def_id))
         )
     }
 
-    pub fn expect_owner(self, id: LocalDefId) -> OwnerNode<'hir> {
+    pub fn expect_owner(self, id: OwnerId) -> OwnerNode<'hir> {
         self.tcx.hir_owner(id).unwrap_or_else(|| bug!("expected owner for {:?}", id)).node
     }
 
     pub fn expect_item(self, id: LocalDefId) -> &'hir Item<'hir> {
-        match self.tcx.hir_owner(id) {
+        match self.tcx.hir_owner(OwnerId { def_id: id }) {
             Some(Owner { node: OwnerNode::Item(item), .. }) => item,
             _ => bug!("expected item, found {}", self.node_to_string(HirId::make_owner(id))),
         }
     }
 
     pub fn expect_impl_item(self, id: LocalDefId) -> &'hir ImplItem<'hir> {
-        match self.tcx.hir_owner(id) {
+        match self.tcx.hir_owner(OwnerId { def_id: id }) {
             Some(Owner { node: OwnerNode::ImplItem(item), .. }) => item,
             _ => bug!("expected impl item, found {}", self.node_to_string(HirId::make_owner(id))),
         }
     }
 
     pub fn expect_trait_item(self, id: LocalDefId) -> &'hir TraitItem<'hir> {
-        match self.tcx.hir_owner(id) {
+        match self.tcx.hir_owner(OwnerId { def_id: id }) {
             Some(Owner { node: OwnerNode::TraitItem(item), .. }) => item,
             _ => bug!("expected trait item, found {}", self.node_to_string(HirId::make_owner(id))),
         }
@@ -839,11 +850,14 @@ impl<'hir> Map<'hir> {
         }
     }
 
-    pub fn expect_foreign_item(self, id: LocalDefId) -> &'hir ForeignItem<'hir> {
+    pub fn expect_foreign_item(self, id: OwnerId) -> &'hir ForeignItem<'hir> {
         match self.tcx.hir_owner(id) {
             Some(Owner { node: OwnerNode::ForeignItem(item), .. }) => item,
             _ => {
-                bug!("expected foreign item, found {}", self.node_to_string(HirId::make_owner(id)))
+                bug!(
+                    "expected foreign item, found {}",
+                    self.node_to_string(HirId::make_owner(id.def_id))
+                )
             }
         }
     }
@@ -1184,7 +1198,13 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
                 ItemKind::ForeignMod { .. } => "foreign mod",
                 ItemKind::GlobalAsm(..) => "global asm",
                 ItemKind::TyAlias(..) => "ty",
-                ItemKind::OpaqueTy(..) => "opaque type",
+                ItemKind::OpaqueTy(ref opaque) => {
+                    if opaque.in_trait {
+                        "opaque type in trait"
+                    } else {
+                        "opaque type"
+                    }
+                }
                 ItemKind::Enum(..) => "enum",
                 ItemKind::Struct(..) => "struct",
                 ItemKind::Union(..) => "union",
@@ -1273,7 +1293,7 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
     // A "crate collector" and "module collector" start at a
     // module item (the former starts at the crate root) but only
     // the former needs to collect it. ItemCollector does not do this for us.
-    collector.submodules.push(CRATE_DEF_ID);
+    collector.submodules.push(CRATE_OWNER_ID);
     tcx.hir().walk_toplevel_module(&mut collector);
 
     let ItemCollector {
@@ -1301,7 +1321,7 @@ struct ItemCollector<'tcx> {
     // otherwise it collects items in some module.
     crate_collector: bool,
     tcx: TyCtxt<'tcx>,
-    submodules: Vec<LocalDefId>,
+    submodules: Vec<OwnerId>,
     items: Vec<ItemId>,
     trait_items: Vec<TraitItemId>,
     impl_items: Vec<ImplItemId>,
@@ -1333,7 +1353,7 @@ impl<'hir> Visitor<'hir> for ItemCollector<'hir> {
 
     fn visit_item(&mut self, item: &'hir Item<'hir>) {
         if associated_body(Node::Item(item)).is_some() {
-            self.body_owners.push(item.def_id);
+            self.body_owners.push(item.def_id.def_id);
         }
 
         self.items.push(item.item_id());
@@ -1369,7 +1389,7 @@ impl<'hir> Visitor<'hir> for ItemCollector<'hir> {
 
     fn visit_trait_item(&mut self, item: &'hir TraitItem<'hir>) {
         if associated_body(Node::TraitItem(item)).is_some() {
-            self.body_owners.push(item.def_id);
+            self.body_owners.push(item.def_id.def_id);
         }
 
         self.trait_items.push(item.trait_item_id());
@@ -1378,7 +1398,7 @@ impl<'hir> Visitor<'hir> for ItemCollector<'hir> {
 
     fn visit_impl_item(&mut self, item: &'hir ImplItem<'hir>) {
         if associated_body(Node::ImplItem(item)).is_some() {
-            self.body_owners.push(item.def_id);
+            self.body_owners.push(item.def_id.def_id);
         }
 
         self.impl_items.push(item.impl_item_id());
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
index 211a614717f8..1ce98a03c8a6 100644
--- a/compiler/rustc_middle/src/hir/mod.rs
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -39,7 +39,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Owner<'tcx> {
 /// bodies.  The Ids are in visitor order.  This is used to partition a pass between modules.
 #[derive(Debug, HashStable, Encodable, Decodable)]
 pub struct ModuleItems {
-    submodules: Box<[LocalDefId]>,
+    submodules: Box<[OwnerId]>,
     items: Box<[ItemId]>,
     trait_items: Box<[TraitItemId]>,
     impl_items: Box<[ImplItemId]>,
@@ -67,10 +67,10 @@ impl ModuleItems {
     pub fn definitions(&self) -> impl Iterator<Item = LocalDefId> + '_ {
         self.items
             .iter()
-            .map(|id| id.def_id)
-            .chain(self.trait_items.iter().map(|id| id.def_id))
-            .chain(self.impl_items.iter().map(|id| id.def_id))
-            .chain(self.foreign_items.iter().map(|id| id.def_id))
+            .map(|id| id.def_id.def_id)
+            .chain(self.trait_items.iter().map(|id| id.def_id.def_id))
+            .chain(self.impl_items.iter().map(|id| id.def_id.def_id))
+            .chain(self.foreign_items.iter().map(|id| id.def_id.def_id))
     }
 
     pub fn par_items(&self, f: impl Fn(ItemId) + Send + Sync) {
@@ -97,7 +97,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn parent_module(self, id: HirId) -> LocalDefId {
-        self.parent_module_from_def_id(id.owner)
+        self.parent_module_from_def_id(id.owner.def_id)
     }
 
     pub fn impl_subject(self, def_id: DefId) -> ImplSubject<'tcx> {
@@ -110,13 +110,13 @@ impl<'tcx> TyCtxt<'tcx> {
 pub fn provide(providers: &mut Providers) {
     providers.parent_module_from_def_id = |tcx, id| {
         let hir = tcx.hir();
-        hir.get_module_parent_node(hir.local_def_id_to_hir_id(id))
+        hir.get_module_parent_node(hir.local_def_id_to_hir_id(id)).def_id
     };
     providers.hir_crate_items = map::hir_crate_items;
     providers.crate_hash = map::crate_hash;
     providers.hir_module_items = map::hir_module_items;
     providers.hir_owner = |tcx, id| {
-        let owner = tcx.hir_crate(()).owners.get(id)?.as_owner()?;
+        let owner = tcx.hir_crate(()).owners.get(id.def_id)?.as_owner()?;
         let node = owner.node();
         Some(Owner { node, hash_without_bodies: owner.nodes.hash_without_bodies })
     };
@@ -128,21 +128,24 @@ pub fn provide(providers: &mut Providers) {
             MaybeOwner::NonOwner(hir_id) => hir_id,
         }
     };
-    providers.hir_owner_nodes = |tcx, id| tcx.hir_crate(()).owners[id].map(|i| &i.nodes);
+    providers.hir_owner_nodes = |tcx, id| tcx.hir_crate(()).owners[id.def_id].map(|i| &i.nodes);
     providers.hir_owner_parent = |tcx, id| {
         // Accessing the local_parent is ok since its value is hashed as part of `id`'s DefPathHash.
-        tcx.opt_local_parent(id).map_or(CRATE_HIR_ID, |parent| {
+        tcx.opt_local_parent(id.def_id).map_or(CRATE_HIR_ID, |parent| {
             let mut parent_hir_id = tcx.hir().local_def_id_to_hir_id(parent);
-            if let Some(local_id) =
-                tcx.hir_crate(()).owners[parent_hir_id.owner].unwrap().parenting.get(&id)
+            if let Some(local_id) = tcx.hir_crate(()).owners[parent_hir_id.owner.def_id]
+                .unwrap()
+                .parenting
+                .get(&id.def_id)
             {
                 parent_hir_id.local_id = *local_id;
             }
             parent_hir_id
         })
     };
-    providers.hir_attrs =
-        |tcx, id| tcx.hir_crate(()).owners[id].as_owner().map_or(AttributeMap::EMPTY, |o| &o.attrs);
+    providers.hir_attrs = |tcx, id| {
+        tcx.hir_crate(()).owners[id.def_id].as_owner().map_or(AttributeMap::EMPTY, |o| &o.attrs)
+    };
     providers.source_span =
         |tcx, def_id| tcx.resolutions(()).source_span.get(def_id).copied().unwrap_or(DUMMY_SP);
     providers.def_span = |tcx, def_id| {
@@ -177,6 +180,7 @@ pub fn provide(providers: &mut Providers) {
         let id = id.expect_local();
         tcx.resolutions(()).expn_that_defined.get(&id).copied().unwrap_or(ExpnId::root())
     };
-    providers.in_scope_traits_map =
-        |tcx, id| tcx.hir_crate(()).owners[id].as_owner().map(|owner_info| &owner_info.trait_map);
+    providers.in_scope_traits_map = |tcx, id| {
+        tcx.hir_crate(()).owners[id.def_id].as_owner().map(|owner_info| &owner_info.trait_map)
+    };
 }
diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index 200de9079c21..d3cf519b633c 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -22,6 +22,7 @@
 //! [c]: https://rust-lang.github.io/chalk/book/canonical_queries/canonicalization.html
 
 use crate::infer::MemberConstraint;
+use crate::mir::ConstraintCategory;
 use crate::ty::subst::GenericArg;
 use crate::ty::{self, BoundVar, List, Region, Ty, TyCtxt};
 use rustc_index::vec::IndexVec;
@@ -43,6 +44,15 @@ pub struct Canonical<'tcx, V> {
 
 pub type CanonicalVarInfos<'tcx> = &'tcx List<CanonicalVarInfo<'tcx>>;
 
+impl<'tcx> ty::TypeFoldable<'tcx> for CanonicalVarInfos<'tcx> {
+    fn try_fold_with<F: ty::FallibleTypeFolder<'tcx>>(
+        self,
+        folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        ty::util::fold_list(self, folder, |tcx, v| tcx.intern_canonical_var_infos(v))
+    }
+}
+
 /// A set of values corresponding to the canonical variables from some
 /// `Canonical`. You can give these values to
 /// `canonical_value.substitute` to substitute them into the canonical
@@ -89,6 +99,7 @@ impl<'tcx> Default for OriginalQueryValues<'tcx> {
 /// a copy of the canonical value in some other inference context,
 /// with fresh inference variables replacing the canonical values.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub struct CanonicalVarInfo<'tcx> {
     pub kind: CanonicalVarKind<'tcx>,
 }
@@ -114,6 +125,7 @@ impl<'tcx> CanonicalVarInfo<'tcx> {
 /// in the type-theory sense of the term -- i.e., a "meta" type system
 /// that analyzes type-like values.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub enum CanonicalVarKind<'tcx> {
     /// Some kind of type inference variable.
     Ty(CanonicalTyVarKind),
@@ -290,20 +302,15 @@ impl<'tcx, V> Canonical<'tcx, V> {
     }
 }
 
-pub type QueryOutlivesConstraint<'tcx> =
-    ty::Binder<'tcx, ty::OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>>;
+pub type QueryOutlivesConstraint<'tcx> = (
+    ty::Binder<'tcx, ty::OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>>,
+    ConstraintCategory<'tcx>,
+);
 
 TrivialTypeTraversalAndLiftImpls! {
     for <'tcx> {
         crate::infer::canonical::Certainty,
-        crate::infer::canonical::CanonicalVarInfo<'tcx>,
-        crate::infer::canonical::CanonicalVarKind<'tcx>,
-    }
-}
-
-TrivialTypeTraversalImpls! {
-    for <'tcx> {
-        crate::infer::canonical::CanonicalVarInfos<'tcx>,
+        crate::infer::canonical::CanonicalTyVarKind,
     }
 }
 
diff --git a/compiler/rustc_middle/src/infer/unify_key.rs b/compiler/rustc_middle/src/infer/unify_key.rs
index f2627885d030..41d8c7ffdb94 100644
--- a/compiler/rustc_middle/src/infer/unify_key.rs
+++ b/compiler/rustc_middle/src/infer/unify_key.rs
@@ -129,7 +129,7 @@ impl<'tcx> UnifyKey for ty::ConstVid<'tcx> {
 }
 
 impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
-    type Error = (ty::Const<'tcx>, ty::Const<'tcx>);
+    type Error = NoError;
 
     fn unify_values(&value1: &Self, &value2: &Self) -> Result<Self, Self::Error> {
         Ok(match (value1.val, value2.val) {
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index be9e5865e541..a180706e1cf0 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -31,7 +31,6 @@
 #![feature(discriminant_kind)]
 #![feature(exhaustive_patterns)]
 #![feature(get_mut_unchecked)]
-#![feature(generic_associated_types)]
 #![feature(if_let_guard)]
 #![feature(map_first_last)]
 #![feature(negative_impls)]
@@ -40,7 +39,6 @@
 #![feature(new_uninit)]
 #![feature(once_cell)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(trusted_len)]
 #![feature(type_alias_impl_trait)]
@@ -86,6 +84,7 @@ pub mod query;
 pub mod arena;
 #[macro_use]
 pub mod dep_graph;
+pub(crate) mod error;
 pub mod hir;
 pub mod infer;
 pub mod lint;
@@ -95,6 +94,7 @@ pub mod mir;
 pub mod thir;
 pub mod traits;
 pub mod ty;
+mod values;
 
 pub mod util {
     pub mod bug;
diff --git a/compiler/rustc_middle/src/metadata.rs b/compiler/rustc_middle/src/metadata.rs
index c8e78747d8e7..5ff014c7815a 100644
--- a/compiler/rustc_middle/src/metadata.rs
+++ b/compiler/rustc_middle/src/metadata.rs
@@ -2,6 +2,7 @@ use crate::ty;
 
 use rustc_hir::def::Res;
 use rustc_macros::HashStable;
+use rustc_span::def_id::DefId;
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 
@@ -18,7 +19,7 @@ pub struct ModChild {
     /// Local variables cannot be exported, so this `Res` doesn't need the ID parameter.
     pub res: Res<!>,
     /// Visibility of the item.
-    pub vis: ty::Visibility,
+    pub vis: ty::Visibility<DefId>,
     /// Span of the item.
     pub span: Span,
     /// A proper `macro_rules` item (not a reexport).
diff --git a/compiler/rustc_middle/src/middle/limits.rs b/compiler/rustc_middle/src/middle/limits.rs
index acced0492efe..53c4d9267849 100644
--- a/compiler/rustc_middle/src/middle/limits.rs
+++ b/compiler/rustc_middle/src/middle/limits.rs
@@ -10,6 +10,7 @@
 //! just peeks and looks for that attribute.
 
 use crate::bug;
+use crate::error::LimitInvalid;
 use crate::ty;
 use rustc_ast::Attribute;
 use rustc_session::Session;
@@ -56,9 +57,6 @@ fn get_limit(krate_attrs: &[Attribute], sess: &Session, name: Symbol, default: u
             match s.as_str().parse() {
                 Ok(n) => return Limit::new(n),
                 Err(e) => {
-                    let mut err =
-                        sess.struct_span_err(attr.span, "`limit` must be a non-negative integer");
-
                     let value_span = attr
                         .meta()
                         .and_then(|meta| meta.name_value_literal_span())
@@ -74,9 +72,7 @@ fn get_limit(krate_attrs: &[Attribute], sess: &Session, name: Symbol, default: u
                         IntErrorKind::Zero => bug!("zero is a valid `limit`"),
                         kind => bug!("unimplemented IntErrorKind variant: {:?}", kind),
                     };
-
-                    err.span_label(value_span, error_str);
-                    err.emit();
+                    sess.emit_err(LimitInvalid { span: attr.span, value_span, error_str });
                 }
             }
         }
diff --git a/compiler/rustc_middle/src/middle/privacy.rs b/compiler/rustc_middle/src/middle/privacy.rs
index 751c7f464822..c595fbec0dd5 100644
--- a/compiler/rustc_middle/src/middle/privacy.rs
+++ b/compiler/rustc_middle/src/middle/privacy.rs
@@ -1,7 +1,7 @@
 //! A pass that checks to make sure private fields and methods aren't used
 //! outside their scopes. This pass will also generate a set of exported items
 //! which are available for use externally when compiled as a library.
-
+use crate::ty::Visibility;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_macros::HashStable;
@@ -27,26 +27,107 @@ pub enum AccessLevel {
     Public,
 }
 
+#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable, Default)]
+pub struct EffectiveVisibility {
+    public: Option<Visibility>,
+    exported: Option<Visibility>,
+    reachable: Option<Visibility>,
+    reachable_from_impl_trait: Option<Visibility>,
+}
+
+impl EffectiveVisibility {
+    pub fn get(&self, tag: AccessLevel) -> Option<&Visibility> {
+        match tag {
+            AccessLevel::Public => &self.public,
+            AccessLevel::Exported => &self.exported,
+            AccessLevel::Reachable => &self.reachable,
+            AccessLevel::ReachableFromImplTrait => &self.reachable_from_impl_trait,
+        }
+        .as_ref()
+    }
+
+    fn get_mut(&mut self, tag: AccessLevel) -> &mut Option<Visibility> {
+        match tag {
+            AccessLevel::Public => &mut self.public,
+            AccessLevel::Exported => &mut self.exported,
+            AccessLevel::Reachable => &mut self.reachable,
+            AccessLevel::ReachableFromImplTrait => &mut self.reachable_from_impl_trait,
+        }
+    }
+
+    pub fn is_public_at_level(&self, tag: AccessLevel) -> bool {
+        self.get(tag).map_or(false, |vis| vis.is_public())
+    }
+}
+
 /// Holds a map of accessibility levels for reachable HIR nodes.
 #[derive(Debug, Clone)]
 pub struct AccessLevels<Id = LocalDefId> {
-    pub map: FxHashMap<Id, AccessLevel>,
+    map: FxHashMap<Id, EffectiveVisibility>,
 }
 
-impl<Id: Hash + Eq> AccessLevels<Id> {
+impl<Id: Hash + Eq + Copy> AccessLevels<Id> {
+    pub fn is_public_at_level(&self, id: Id, tag: AccessLevel) -> bool {
+        self.get_effective_vis(id)
+            .map_or(false, |effective_vis| effective_vis.is_public_at_level(tag))
+    }
+
     /// See `AccessLevel::Reachable`.
     pub fn is_reachable(&self, id: Id) -> bool {
-        self.map.get(&id) >= Some(&AccessLevel::Reachable)
+        self.is_public_at_level(id, AccessLevel::Reachable)
     }
 
     /// See `AccessLevel::Exported`.
     pub fn is_exported(&self, id: Id) -> bool {
-        self.map.get(&id) >= Some(&AccessLevel::Exported)
+        self.is_public_at_level(id, AccessLevel::Exported)
     }
 
     /// See `AccessLevel::Public`.
     pub fn is_public(&self, id: Id) -> bool {
-        self.map.get(&id) >= Some(&AccessLevel::Public)
+        self.is_public_at_level(id, AccessLevel::Public)
+    }
+
+    pub fn get_access_level(&self, id: Id) -> Option<AccessLevel> {
+        self.get_effective_vis(id).and_then(|effective_vis| {
+            for level in [
+                AccessLevel::Public,
+                AccessLevel::Exported,
+                AccessLevel::Reachable,
+                AccessLevel::ReachableFromImplTrait,
+            ] {
+                if effective_vis.is_public_at_level(level) {
+                    return Some(level);
+                }
+            }
+            None
+        })
+    }
+
+    pub fn set_access_level(&mut self, id: Id, tag: AccessLevel) {
+        let mut effective_vis = self.get_effective_vis(id).copied().unwrap_or_default();
+        for level in [
+            AccessLevel::Public,
+            AccessLevel::Exported,
+            AccessLevel::Reachable,
+            AccessLevel::ReachableFromImplTrait,
+        ] {
+            if level <= tag {
+                *effective_vis.get_mut(level) = Some(Visibility::Public);
+            }
+        }
+        self.map.insert(id, effective_vis);
+    }
+
+    pub fn get_effective_vis(&self, id: Id) -> Option<&EffectiveVisibility> {
+        self.map.get(&id)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (&Id, &EffectiveVisibility)> {
+        self.map.iter()
+    }
+
+    pub fn map_id<OutId: Hash + Eq + Copy>(&self, f: impl Fn(Id) -> OutId) -> AccessLevels<OutId> {
+        AccessLevels { map: self.map.iter().map(|(k, v)| (f(*k), *v)).collect() }
     }
 }
 
diff --git a/compiler/rustc_middle/src/middle/resolve_lifetime.rs b/compiler/rustc_middle/src/middle/resolve_lifetime.rs
index a171f5711dcf..c3bf1c717d9a 100644
--- a/compiler/rustc_middle/src/middle/resolve_lifetime.rs
+++ b/compiler/rustc_middle/src/middle/resolve_lifetime.rs
@@ -2,9 +2,9 @@
 
 use crate::ty;
 
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::ItemLocalId;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::def_id::DefId;
+use rustc_hir::{ItemLocalId, OwnerId};
 use rustc_macros::HashStable;
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, HashStable)]
@@ -49,12 +49,7 @@ pub enum ObjectLifetimeDefault {
 pub struct ResolveLifetimes {
     /// Maps from every use of a named (not anonymous) lifetime to a
     /// `Region` describing how that region is bound
-    pub defs: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Region>>,
+    pub defs: FxHashMap<OwnerId, FxHashMap<ItemLocalId, Region>>,
 
-    /// Set of lifetime def ids that are late-bound; a region can
-    /// be late-bound if (a) it does NOT appear in a where-clause and
-    /// (b) it DOES appear in the arguments.
-    pub late_bound: FxHashMap<LocalDefId, FxHashSet<LocalDefId>>,
-
-    pub late_bound_vars: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Vec<ty::BoundVariableKind>>>,
+    pub late_bound_vars: FxHashMap<OwnerId, FxHashMap<ItemLocalId, Vec<ty::BoundVariableKind>>>,
 }
diff --git a/compiler/rustc_middle/src/mir/basic_blocks.rs b/compiler/rustc_middle/src/mir/basic_blocks.rs
index 78080fcd581f..752cbdeae6b2 100644
--- a/compiler/rustc_middle/src/mir/basic_blocks.rs
+++ b/compiler/rustc_middle/src/mir/basic_blocks.rs
@@ -86,7 +86,7 @@ impl<'tcx> BasicBlocks<'tcx> {
     ///
     /// You will only ever need this if you have also called [`BasicBlocks::as_mut_preserves_cfg`].
     /// All other methods that allow you to mutate the basic blocks also call this method
-    /// themselves, thereby avoiding any risk of accidentaly cache invalidation.
+    /// themselves, thereby avoiding any risk of accidentally cache invalidation.
     pub fn invalidate_cfg_cache(&mut self) {
         self.predecessor_cache.invalidate();
         self.switch_source_cache.invalidate();
diff --git a/compiler/rustc_middle/src/mir/interpret/mod.rs b/compiler/rustc_middle/src/mir/interpret/mod.rs
index 0fc1217d5719..5e3dfcbcc496 100644
--- a/compiler/rustc_middle/src/mir/interpret/mod.rs
+++ b/compiler/rustc_middle/src/mir/interpret/mod.rs
@@ -137,7 +137,7 @@ pub use self::pointer::{Pointer, PointerArithmetic, Provenance};
 /// - A constant
 /// - A static
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, Lift)]
+#[derive(HashStable, Lift, TypeFoldable, TypeVisitable)]
 pub struct GlobalId<'tcx> {
     /// For a constant or static, the `Instance` of the item itself.
     /// For a promoted global, the `Instance` of the function they belong to.
diff --git a/compiler/rustc_middle/src/mir/interpret/queries.rs b/compiler/rustc_middle/src/mir/interpret/queries.rs
index 786927e2dad7..734c31192c7c 100644
--- a/compiler/rustc_middle/src/mir/interpret/queries.rs
+++ b/compiler/rustc_middle/src/mir/interpret/queries.rs
@@ -36,7 +36,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn const_eval_resolve(
         self,
         param_env: ty::ParamEnv<'tcx>,
-        ct: ty::Unevaluated<'tcx>,
+        ct: mir::UnevaluatedConst<'tcx>,
         span: Option<Span>,
     ) -> EvalToConstValueResult<'tcx> {
         // Cannot resolve `Unevaluated` constants that contain inference
@@ -49,7 +49,11 @@ impl<'tcx> TyCtxt<'tcx> {
             bug!("did not expect inference variables here");
         }
 
-        match ty::Instance::resolve_opt_const_arg(self, param_env, ct.def, ct.substs) {
+        match ty::Instance::resolve_opt_const_arg(
+            self, param_env,
+            // FIXME: maybe have a seperate version for resolving mir::UnevaluatedConst?
+            ct.def, ct.substs,
+        ) {
             Ok(Some(instance)) => {
                 let cid = GlobalId { instance, promoted: ct.promoted };
                 self.const_eval_global_id(param_env, cid, span)
@@ -63,7 +67,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn const_eval_resolve_for_typeck(
         self,
         param_env: ty::ParamEnv<'tcx>,
-        ct: ty::Unevaluated<'tcx>,
+        ct: ty::UnevaluatedConst<'tcx>,
         span: Option<Span>,
     ) -> EvalToValTreeResult<'tcx> {
         // Cannot resolve `Unevaluated` constants that contain inference
@@ -78,7 +82,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
         match ty::Instance::resolve_opt_const_arg(self, param_env, ct.def, ct.substs) {
             Ok(Some(instance)) => {
-                let cid = GlobalId { instance, promoted: ct.promoted };
+                let cid = GlobalId { instance, promoted: None };
                 self.const_eval_global_id_for_typeck(param_env, cid, span)
             }
             Ok(None) => Err(ErrorHandled::TooGeneric),
@@ -211,7 +215,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         param_env: ty::ParamEnv<'tcx>,
         constant: mir::ConstantKind<'tcx>,
-    ) -> mir::DestructuredMirConstant<'tcx> {
+    ) -> mir::DestructuredConstant<'tcx> {
         self.try_destructure_mir_constant(param_env.and(constant)).unwrap()
     }
 }
diff --git a/compiler/rustc_middle/src/mir/interpret/value.rs b/compiler/rustc_middle/src/mir/interpret/value.rs
index d4fad7f1ecdd..ac5fddb7ad1e 100644
--- a/compiler/rustc_middle/src/mir/interpret/value.rs
+++ b/compiler/rustc_middle/src/mir/interpret/value.rs
@@ -8,7 +8,7 @@ use rustc_apfloat::{
 use rustc_macros::HashStable;
 use rustc_target::abi::{HasDataLayout, Size};
 
-use crate::ty::{Lift, ParamEnv, ScalarInt, Ty, TyCtxt};
+use crate::ty::{ParamEnv, ScalarInt, Ty, TyCtxt};
 
 use super::{
     AllocId, AllocRange, ConstAllocation, InterpResult, Pointer, PointerArithmetic, Provenance,
@@ -27,7 +27,7 @@ pub struct ConstAlloc<'tcx> {
 /// Represents a constant value in Rust. `Scalar` and `Slice` are optimizations for
 /// array length computations, enum discriminants and the pattern matching logic.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Hash)]
-#[derive(HashStable)]
+#[derive(HashStable, Lift)]
 pub enum ConstValue<'tcx> {
     /// Used only for types with `layout::abi::Scalar` ABI.
     ///
@@ -53,22 +53,6 @@ pub enum ConstValue<'tcx> {
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 static_assert_size!(ConstValue<'_>, 32);
 
-impl<'a, 'tcx> Lift<'tcx> for ConstValue<'a> {
-    type Lifted = ConstValue<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ConstValue<'tcx>> {
-        Some(match self {
-            ConstValue::Scalar(s) => ConstValue::Scalar(s),
-            ConstValue::ZeroSized => ConstValue::ZeroSized,
-            ConstValue::Slice { data, start, end } => {
-                ConstValue::Slice { data: tcx.lift(data)?, start, end }
-            }
-            ConstValue::ByRef { alloc, offset } => {
-                ConstValue::ByRef { alloc: tcx.lift(alloc)?, offset }
-            }
-        })
-    }
-}
-
 impl<'tcx> ConstValue<'tcx> {
     #[inline]
     pub fn try_to_scalar(&self) -> Option<Scalar<AllocId>> {
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 7784449d605e..78a167888158 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -3,22 +3,22 @@
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/mir/index.html
 
 use crate::mir::interpret::{
-    AllocRange, ConstAllocation, ConstValue, GlobalAlloc, LitToConstInput, Scalar,
+    AllocRange, ConstAllocation, ConstValue, ErrorHandled, GlobalAlloc, LitToConstInput, Scalar,
 };
 use crate::mir::visit::MirVisitable;
 use crate::ty::codec::{TyDecoder, TyEncoder};
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{FmtPrinter, Printer};
-use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
 use crate::ty::{self, List, Ty, TyCtxt};
 use crate::ty::{AdtDef, InstanceDef, ScalarInt, UserTypeAnnotationIndex};
+use crate::ty::{GenericArg, InternalSubsts, SubstsRef};
 
 use rustc_data_structures::captures::Captures;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::{CtorKind, Namespace};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
-use rustc_hir::{self, GeneratorKind};
+use rustc_hir::{self, GeneratorKind, ImplicitSelfKind};
 use rustc_hir::{self as hir, HirId};
 use rustc_session::Session;
 use rustc_target::abi::{Size, VariantIdx};
@@ -653,22 +653,6 @@ pub enum BindingForm<'tcx> {
     RefForGuard,
 }
 
-/// Represents what type of implicit self a function has, if any.
-#[derive(Clone, Copy, PartialEq, Debug, TyEncodable, TyDecodable, HashStable)]
-pub enum ImplicitSelfKind {
-    /// Represents a `fn x(self);`.
-    Imm,
-    /// Represents a `fn x(mut self);`.
-    Mut,
-    /// Represents a `fn x(&self);`.
-    ImmRef,
-    /// Represents a `fn x(&mut self);`.
-    MutRef,
-    /// Represents when a function does not have a self argument or
-    /// when a function has a `self: X` argument.
-    None,
-}
-
 TrivialTypeTraversalAndLiftImpls! { BindingForm<'tcx>, }
 
 mod binding_form_impl {
@@ -839,10 +823,6 @@ pub struct LocalDecl<'tcx> {
     pub source_info: SourceInfo,
 }
 
-// `LocalDecl` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(LocalDecl<'_>, 56);
-
 /// Extra information about a some locals that's used for diagnostics and for
 /// classifying variables into local variables, statics, etc, which is needed e.g.
 /// for unsafety checking.
@@ -1317,10 +1297,6 @@ pub struct Statement<'tcx> {
     pub kind: StatementKind<'tcx>,
 }
 
-// `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(Statement<'_>, 32);
-
 impl Statement<'_> {
     /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
     /// invalidating statement indices in `Location`s.
@@ -1370,13 +1346,7 @@ impl Debug for Statement<'_> {
                 write!(fmt, "Coverage::{:?} for {:?}", kind, rgn)
             }
             Coverage(box ref coverage) => write!(fmt, "Coverage::{:?}", coverage.kind),
-            CopyNonOverlapping(box crate::mir::CopyNonOverlapping {
-                ref src,
-                ref dst,
-                ref count,
-            }) => {
-                write!(fmt, "copy_nonoverlapping(src={:?}, dst={:?}, count={:?})", src, dst, count)
-            }
+            Intrinsic(box ref intrinsic) => write!(fmt, "{intrinsic}"),
             Nop => write!(fmt, "nop"),
         }
     }
@@ -1410,6 +1380,7 @@ impl<V, T> ProjectionElem<V, T> {
 
             Self::Field(_, _)
             | Self::Index(_)
+            | Self::OpaqueCast(_)
             | Self::ConstantIndex { .. }
             | Self::Subslice { .. }
             | Self::Downcast(_, _) => false,
@@ -1457,7 +1428,7 @@ pub struct PlaceRef<'tcx> {
 // Once we stop implementing `Ord` for `DefId`,
 // this impl will be unnecessary. Until then, we'll
 // leave this impl in place to prevent re-adding a
-// dependnecy on the `Ord` impl for `DefId`
+// dependency on the `Ord` impl for `DefId`
 impl<'tcx> !PartialOrd for PlaceRef<'tcx> {}
 
 impl<'tcx> Place<'tcx> {
@@ -1478,7 +1449,9 @@ impl<'tcx> Place<'tcx> {
     /// It's guaranteed to be in the first place
     pub fn has_deref(&self) -> bool {
         // To make sure this is not accidently used in wrong mir phase
-        debug_assert!(!self.projection[1..].contains(&PlaceElem::Deref));
+        debug_assert!(
+            self.projection.is_empty() || !self.projection[1..].contains(&PlaceElem::Deref)
+        );
         self.projection.first() == Some(&PlaceElem::Deref)
     }
 
@@ -1602,7 +1575,9 @@ impl Debug for Place<'_> {
     fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
         for elem in self.projection.iter().rev() {
             match elem {
-                ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
+                ProjectionElem::OpaqueCast(_)
+                | ProjectionElem::Downcast(_, _)
+                | ProjectionElem::Field(_, _) => {
                     write!(fmt, "(").unwrap();
                 }
                 ProjectionElem::Deref => {
@@ -1618,6 +1593,9 @@ impl Debug for Place<'_> {
 
         for elem in self.projection.iter() {
             match elem {
+                ProjectionElem::OpaqueCast(ty) => {
+                    write!(fmt, " as {})", ty)?;
+                }
                 ProjectionElem::Downcast(Some(name), _index) => {
                     write!(fmt, " as {})", name)?;
                 }
@@ -1846,6 +1824,7 @@ impl<'tcx> Rvalue<'tcx> {
             // While the model is undecided, we should be conservative. See
             // <https://www.ralfj.de/blog/2022/04/11/provenance-exposed.html>
             Rvalue::Cast(CastKind::PointerExposeAddress, _, _) => false,
+            Rvalue::Cast(CastKind::DynStar, _, _) => false,
 
             Rvalue::Use(_)
             | Rvalue::CopyForDeref(_)
@@ -2055,6 +2034,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
 /// particular, one must be wary of `NaN`!
 
 #[derive(Clone, Copy, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub struct Constant<'tcx> {
     pub span: Span,
 
@@ -2073,6 +2053,10 @@ pub struct Constant<'tcx> {
 pub enum ConstantKind<'tcx> {
     /// This constant came from the type system
     Ty(ty::Const<'tcx>),
+
+    /// An unevaluated mir constant which is not part of the type system.
+    Unevaluated(UnevaluatedConst<'tcx>, Ty<'tcx>),
+
     /// This constant cannot go back into the type system, as it represents
     /// something the type system cannot handle (e.g. pointers).
     Val(interpret::ConstValue<'tcx>, Ty<'tcx>),
@@ -2098,20 +2082,11 @@ impl<'tcx> Constant<'tcx> {
 }
 
 impl<'tcx> ConstantKind<'tcx> {
-    /// Returns `None` if the constant is not trivially safe for use in the type system.
-    #[inline]
-    pub fn const_for_ty(&self) -> Option<ty::Const<'tcx>> {
-        match self {
-            ConstantKind::Ty(c) => Some(*c),
-            ConstantKind::Val(..) => None,
-        }
-    }
-
     #[inline(always)]
     pub fn ty(&self) -> Ty<'tcx> {
         match self {
             ConstantKind::Ty(c) => c.ty(),
-            ConstantKind::Val(_, ty) => *ty,
+            ConstantKind::Val(_, ty) | ConstantKind::Unevaluated(_, ty) => *ty,
         }
     }
 
@@ -2123,6 +2098,7 @@ impl<'tcx> ConstantKind<'tcx> {
                 _ => None,
             },
             ConstantKind::Val(val, _) => Some(val),
+            ConstantKind::Unevaluated(..) => None,
         }
     }
 
@@ -2137,6 +2113,7 @@ impl<'tcx> ConstantKind<'tcx> {
                 _ => None,
             },
             ConstantKind::Val(val, _) => val.try_to_scalar(),
+            ConstantKind::Unevaluated(..) => None,
         }
     }
 
@@ -2169,6 +2146,14 @@ impl<'tcx> ConstantKind<'tcx> {
                 }
             }
             Self::Val(_, _) => self,
+            Self::Unevaluated(uneval, ty) => {
+                // FIXME: We might want to have a `try_eval`-like function on `Unevaluated`
+                match tcx.const_eval_resolve(param_env, uneval, None) {
+                    Ok(val) => Self::Val(val, ty),
+                    Err(ErrorHandled::TooGeneric | ErrorHandled::Linted) => self,
+                    Err(_) => Self::Ty(tcx.const_error(ty)),
+                }
+            }
         }
     }
 
@@ -2194,6 +2179,18 @@ impl<'tcx> ConstantKind<'tcx> {
                     tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(ty)).ok()?.size;
                 val.try_to_bits(size)
             }
+            Self::Unevaluated(uneval, ty) => {
+                match tcx.const_eval_resolve(param_env, *uneval, None) {
+                    Ok(val) => {
+                        let size = tcx
+                            .layout_of(param_env.with_reveal_all_normalized(tcx).and(*ty))
+                            .ok()?
+                            .size;
+                        val.try_to_bits(size)
+                    }
+                    Err(_) => None,
+                }
+            }
         }
     }
 
@@ -2202,6 +2199,12 @@ impl<'tcx> ConstantKind<'tcx> {
         match self {
             Self::Ty(ct) => ct.try_eval_bool(tcx, param_env),
             Self::Val(val, _) => val.try_to_bool(),
+            Self::Unevaluated(uneval, _) => {
+                match tcx.const_eval_resolve(param_env, *uneval, None) {
+                    Ok(val) => val.try_to_bool(),
+                    Err(_) => None,
+                }
+            }
         }
     }
 
@@ -2210,6 +2213,12 @@ impl<'tcx> ConstantKind<'tcx> {
         match self {
             Self::Ty(ct) => ct.try_eval_usize(tcx, param_env),
             Self::Val(val, _) => val.try_to_machine_usize(tcx),
+            Self::Unevaluated(uneval, _) => {
+                match tcx.const_eval_resolve(param_env, *uneval, None) {
+                    Ok(val) => val.try_to_machine_usize(tcx),
+                    Err(_) => None,
+                }
+            }
         }
     }
 
@@ -2267,7 +2276,7 @@ impl<'tcx> ConstantKind<'tcx> {
         Self::from_opt_const_arg_anon_const(tcx, ty::WithOptConstParam::unknown(def_id), param_env)
     }
 
-    #[instrument(skip(tcx), level = "debug")]
+    #[instrument(skip(tcx), level = "debug", ret)]
     pub fn from_inline_const(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
         let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
         let body_id = match tcx.hir().get(hir_id) {
@@ -2305,21 +2314,18 @@ impl<'tcx> ConstantKind<'tcx> {
         let substs =
             ty::InlineConstSubsts::new(tcx, ty::InlineConstSubstsParts { parent_substs, ty })
                 .substs;
-        let uneval_const = tcx.mk_const(ty::ConstS {
-            kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                def: ty::WithOptConstParam::unknown(def_id).to_global(),
-                substs,
-                promoted: None,
-            }),
-            ty,
-        });
-        debug!(?uneval_const);
-        debug_assert!(!uneval_const.has_free_regions());
 
-        Self::Ty(uneval_const)
+        let uneval = UnevaluatedConst {
+            def: ty::WithOptConstParam::unknown(def_id).to_global(),
+            substs,
+            promoted: None,
+        };
+        debug_assert!(!uneval.has_free_regions());
+
+        Self::Unevaluated(uneval, ty)
     }
 
-    #[instrument(skip(tcx), level = "debug")]
+    #[instrument(skip(tcx), level = "debug", ret)]
     fn from_opt_const_arg_anon_const(
         tcx: TyCtxt<'tcx>,
         def: ty::WithOptConstParam<LocalDefId>,
@@ -2397,29 +2403,26 @@ impl<'tcx> ConstantKind<'tcx> {
 
         let hir_id = tcx.hir().local_def_id_to_hir_id(def.did);
         let span = tcx.hir().span(hir_id);
-        let uneval = ty::Unevaluated::new(def.to_global(), substs);
+        let uneval = UnevaluatedConst::new(def.to_global(), substs);
         debug!(?span, ?param_env);
 
         match tcx.const_eval_resolve(param_env, uneval, Some(span)) {
             Ok(val) => {
-                debug!("evaluated const value: {:?}", val);
+                debug!("evaluated const value");
                 Self::Val(val, ty)
             }
             Err(_) => {
                 debug!("error encountered during evaluation");
                 // Error was handled in `const_eval_resolve`. Here we just create a
                 // new unevaluated const and error hard later in codegen
-                let ty_const = tcx.mk_const(ty::ConstS {
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
+                Self::Unevaluated(
+                    UnevaluatedConst {
                         def: def.to_global(),
                         substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
                         promoted: None,
-                    }),
+                    },
                     ty,
-                });
-                debug!(?ty_const);
-
-                Self::Ty(ty_const)
+                )
             }
         }
     }
@@ -2430,11 +2433,40 @@ impl<'tcx> ConstantKind<'tcx> {
                 let const_val = tcx.valtree_to_const_val((c.ty(), valtree));
                 Self::Val(const_val, c.ty())
             }
+            ty::ConstKind::Unevaluated(uv) => Self::Unevaluated(uv.expand(), c.ty()),
             _ => Self::Ty(c),
         }
     }
 }
 
+/// An unevaluated (potentially generic) constant used in MIR.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Lift)]
+#[derive(Hash, HashStable)]
+pub struct UnevaluatedConst<'tcx> {
+    pub def: ty::WithOptConstParam<DefId>,
+    pub substs: SubstsRef<'tcx>,
+    pub promoted: Option<Promoted>,
+}
+
+impl<'tcx> UnevaluatedConst<'tcx> {
+    // FIXME: probably should get rid of this method. It's also wrong to
+    // shrink and then later expand a promoted.
+    #[inline]
+    pub fn shrink(self) -> ty::UnevaluatedConst<'tcx> {
+        ty::UnevaluatedConst { def: self.def, substs: self.substs }
+    }
+}
+
+impl<'tcx> UnevaluatedConst<'tcx> {
+    #[inline]
+    pub fn new(
+        def: ty::WithOptConstParam<DefId>,
+        substs: SubstsRef<'tcx>,
+    ) -> UnevaluatedConst<'tcx> {
+        UnevaluatedConst { def, substs, promoted: Default::default() }
+    }
+}
+
 /// A collection of projections into user types.
 ///
 /// They are projections because a binding can occur a part of a
@@ -2584,8 +2616,6 @@ impl UserTypeProjection {
     }
 }
 
-TrivialTypeTraversalAndLiftImpls! { ProjectionKind, }
-
 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         Ok(UserTypeProjection {
@@ -2630,6 +2660,11 @@ impl<'tcx> Display for ConstantKind<'tcx> {
         match *self {
             ConstantKind::Ty(c) => pretty_print_const(c, fmt, true),
             ConstantKind::Val(val, ty) => pretty_print_const_value(val, ty, fmt, true),
+            // FIXME(valtrees): Correctly print mir constants.
+            ConstantKind::Unevaluated(..) => {
+                fmt.write_str("_")?;
+                Ok(())
+            }
         }
     }
 }
@@ -2651,15 +2686,7 @@ fn pretty_print_const<'tcx>(
 }
 
 fn pretty_print_byte_str(fmt: &mut Formatter<'_>, byte_str: &[u8]) -> fmt::Result {
-    fmt.write_str("b\"")?;
-    for &c in byte_str {
-        for e in std::ascii::escape_default(c) {
-            fmt.write_char(e as char)?;
-        }
-    }
-    fmt.write_str("\"")?;
-
-    Ok(())
+    write!(fmt, "b\"{}\"", byte_str.escape_ascii())
 }
 
 fn comma_sep<'tcx>(fmt: &mut Formatter<'_>, elems: Vec<ConstantKind<'tcx>>) -> fmt::Result {
@@ -2906,3 +2933,17 @@ impl Location {
         }
     }
 }
+
+// Some nodes are used a lot. Make sure they don't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+mod size_asserts {
+    use super::*;
+    use rustc_data_structures::static_assert_size;
+    // These are in alphabetical order, which is easy to maintain.
+    static_assert_size!(BasicBlockData<'_>, 144);
+    static_assert_size!(LocalDecl<'_>, 56);
+    static_assert_size!(Statement<'_>, 32);
+    static_assert_size!(StatementKind<'_>, 16);
+    static_assert_size!(Terminator<'_>, 112);
+    static_assert_size!(TerminatorKind<'_>, 96);
+}
diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index 21ae121e1ce6..fdda62719ee1 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -182,7 +182,7 @@ impl<'tcx> MonoItem<'tcx> {
         match *self {
             MonoItem::Fn(Instance { def, .. }) => def.def_id().as_local(),
             MonoItem::Static(def_id) => def_id.as_local(),
-            MonoItem::GlobalAsm(item_id) => Some(item_id.def_id),
+            MonoItem::GlobalAsm(item_id) => Some(item_id.def_id.def_id),
         }
         .map(|def_id| tcx.def_span(def_id))
     }
@@ -373,7 +373,7 @@ impl<'tcx> CodegenUnit<'tcx> {
                         }
                     }
                     MonoItem::Static(def_id) => def_id.as_local().map(Idx::index),
-                    MonoItem::GlobalAsm(item_id) => Some(item_id.def_id.index()),
+                    MonoItem::GlobalAsm(item_id) => Some(item_id.def_id.def_id.index()),
                 },
                 item.symbol_name(tcx),
             )
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 88c16189f1dc..05dcfba77b23 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -464,12 +464,13 @@ impl<'tcx> Visitor<'tcx> for ExtraComments<'tcx> {
             let val = match literal {
                 ConstantKind::Ty(ct) => match ct.kind() {
                     ty::ConstKind::Param(p) => format!("Param({})", p),
-                    ty::ConstKind::Unevaluated(uv) => format!(
-                        "Unevaluated({}, {:?}, {:?})",
-                        self.tcx.def_path_str(uv.def.did),
-                        uv.substs,
-                        uv.promoted,
-                    ),
+                    ty::ConstKind::Unevaluated(uv) => {
+                        format!(
+                            "Unevaluated({}, {:?})",
+                            self.tcx.def_path_str(uv.def.did),
+                            uv.substs,
+                        )
+                    }
                     ty::ConstKind::Value(val) => format!("Value({})", fmt_valtree(&val)),
                     ty::ConstKind::Error(_) => "Error".to_string(),
                     // These variants shouldn't exist in the MIR.
@@ -477,6 +478,14 @@ impl<'tcx> Visitor<'tcx> for ExtraComments<'tcx> {
                     | ty::ConstKind::Infer(_)
                     | ty::ConstKind::Bound(..) => bug!("unexpected MIR constant: {:?}", literal),
                 },
+                ConstantKind::Unevaluated(uv, _) => {
+                    format!(
+                        "Unevaluated({}, {:?}, {:?})",
+                        self.tcx.def_path_str(uv.def.did),
+                        uv.substs,
+                        uv.promoted,
+                    )
+                }
                 // To keep the diffs small, we render this like we render `ty::Const::Value`.
                 //
                 // This changes once `ty::Const::Value` is represented using valtrees.
@@ -696,9 +705,9 @@ pub fn write_allocations<'tcx>(
     struct CollectAllocIds(BTreeSet<AllocId>);
 
     impl<'tcx> Visitor<'tcx> for CollectAllocIds {
-        fn visit_constant(&mut self, c: &Constant<'tcx>, loc: Location) {
+        fn visit_constant(&mut self, c: &Constant<'tcx>, _: Location) {
             match c.literal {
-                ConstantKind::Ty(c) => self.visit_const(c, loc),
+                ConstantKind::Ty(_) | ConstantKind::Unevaluated(..) => {}
                 ConstantKind::Val(val, _) => {
                     self.0.extend(alloc_ids_from_const_val(val));
                 }
diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs
index 594c14a642de..efd7357afc46 100644
--- a/compiler/rustc_middle/src/mir/query.rs
+++ b/compiler/rustc_middle/src/mir/query.rs
@@ -327,7 +327,7 @@ rustc_data_structures::static_assert_size!(ConstraintCategory<'_>, 16);
 ///
 /// See also `rustc_const_eval::borrow_check::constraints`.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
-#[derive(TyEncodable, TyDecodable, HashStable)]
+#[derive(TyEncodable, TyDecodable, HashStable, Lift, TypeVisitable, TypeFoldable)]
 pub enum ConstraintCategory<'tcx> {
     Return(ReturnConstraint),
     Yield,
@@ -369,7 +369,7 @@ pub enum ConstraintCategory<'tcx> {
 }
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
-#[derive(TyEncodable, TyDecodable, HashStable)]
+#[derive(TyEncodable, TyDecodable, HashStable, TypeVisitable, TypeFoldable)]
 pub enum ReturnConstraint {
     Normal,
     ClosureUpvar(Field),
@@ -392,16 +392,9 @@ pub enum ClosureOutlivesSubject<'tcx> {
     Region(ty::RegionVid),
 }
 
-/// The constituent parts of a type level constant of kind ADT or array.
-#[derive(Copy, Clone, Debug, HashStable)]
-pub struct DestructuredConst<'tcx> {
-    pub variant: Option<VariantIdx>,
-    pub fields: &'tcx [ty::Const<'tcx>],
-}
-
 /// The constituent parts of a mir constant of kind ADT or array.
 #[derive(Copy, Clone, Debug, HashStable)]
-pub struct DestructuredMirConstant<'tcx> {
+pub struct DestructuredConstant<'tcx> {
     pub variant: Option<VariantIdx>,
     pub fields: &'tcx [ConstantKind<'tcx>],
 }
diff --git a/compiler/rustc_middle/src/mir/spanview.rs b/compiler/rustc_middle/src/mir/spanview.rs
index 6e64a3b80c1f..4e06d91012c0 100644
--- a/compiler/rustc_middle/src/mir/spanview.rs
+++ b/compiler/rustc_middle/src/mir/spanview.rs
@@ -249,7 +249,7 @@ pub fn statement_kind_name(statement: &Statement<'_>) -> &'static str {
         Retag(..) => "Retag",
         AscribeUserType(..) => "AscribeUserType",
         Coverage(..) => "Coverage",
-        CopyNonOverlapping(..) => "CopyNonOverlapping",
+        Intrinsic(..) => "Intrinsic",
         Nop => "Nop",
     }
 }
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index 3426f5f43f0b..ee8377d1987c 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -82,9 +82,10 @@ pub enum MirPhase {
     ///    access to. This occurs in generator bodies. Such locals do not behave like other locals,
     ///    because they eg may be aliased in surprising ways. Runtime MIR has no such special locals -
     ///    all generator bodies are lowered and so all places that look like locals really are locals.
-    ///  - Const prop lints: The lint pass which reports eg `200_u8 + 200_u8` as an error is run as a
-    ///    part of analysis to runtime MIR lowering. This means that transformations which may supress
-    ///    such errors may not run on analysis MIR.
+    ///
+    /// Also note that the lint pass which reports eg `200_u8 + 200_u8` as an error is run as a part
+    /// of analysis to runtime MIR lowering. To ensure lints are reported reliably, this means that
+    /// transformations which may supress such errors should not run on analysis MIR.
     Runtime(RuntimePhase),
 }
 
@@ -327,12 +328,40 @@ pub enum StatementKind<'tcx> {
     /// executed.
     Coverage(Box<Coverage>),
 
+    /// Denotes a call to an intrinsic that does not require an unwind path and always returns.
+    /// This avoids adding a new block and a terminator for simple intrinsics.
+    Intrinsic(Box<NonDivergingIntrinsic<'tcx>>),
+
+    /// No-op. Useful for deleting instructions without affecting statement indices.
+    Nop,
+}
+
+#[derive(
+    Clone,
+    TyEncodable,
+    TyDecodable,
+    Debug,
+    PartialEq,
+    Hash,
+    HashStable,
+    TypeFoldable,
+    TypeVisitable
+)]
+pub enum NonDivergingIntrinsic<'tcx> {
+    /// Denotes a call to the intrinsic function `assume`.
+    ///
+    /// The operand must be a boolean. Optimizers may use the value of the boolean to backtrack its
+    /// computation to infer information about other variables. So if the boolean came from a
+    /// `x < y` operation, subsequent operations on `x` and `y` could elide various bound checks.
+    /// If the argument is `false`, this operation is equivalent to `TerminatorKind::Unreachable`.
+    Assume(Operand<'tcx>),
+
     /// Denotes a call to the intrinsic function `copy_nonoverlapping`.
     ///
     /// First, all three operands are evaluated. `src` and `dest` must each be a reference, pointer,
     /// or `Box` pointing to the same type `T`. `count` must evaluate to a `usize`. Then, `src` and
     /// `dest` are dereferenced, and `count * size_of::<T>()` bytes beginning with the first byte of
-    /// the `src` place are copied to the continguous range of bytes beginning with the first byte
+    /// the `src` place are copied to the contiguous range of bytes beginning with the first byte
     /// of `dest`.
     ///
     /// **Needs clarification**: In what order are operands computed and dereferenced? It should
@@ -340,10 +369,18 @@ pub enum StatementKind<'tcx> {
     ///
     /// **Needs clarification**: Is this typed or not, ie is there a typed load and store involved?
     /// I vaguely remember Ralf saying somewhere that he thought it should not be.
-    CopyNonOverlapping(Box<CopyNonOverlapping<'tcx>>),
+    CopyNonOverlapping(CopyNonOverlapping<'tcx>),
+}
 
-    /// No-op. Useful for deleting instructions without affecting statement indices.
-    Nop,
+impl std::fmt::Display for NonDivergingIntrinsic<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Assume(op) => write!(f, "assume({op:?})"),
+            Self::CopyNonOverlapping(CopyNonOverlapping { src, dst, count }) => {
+                write!(f, "copy_nonoverlapping(dst = {dst:?}, src = {src:?}, count = {count:?})")
+            }
+        }
+    }
 }
 
 /// Describes what kind of retag is to be performed.
@@ -378,7 +415,7 @@ pub enum FakeReadCause {
     /// Some(closure_def_id).
     /// Otherwise, the value of the optional LocalDefId will be None.
     //
-    // We can use LocaDefId here since fake read statements are removed
+    // We can use LocalDefId here since fake read statements are removed
     // before codegen in the `CleanupNonCodegenStatements` pass.
     ForMatchedPlace(Option<LocalDefId>),
 
@@ -452,7 +489,7 @@ pub struct CopyNonOverlapping<'tcx> {
 ///     must also be `cleanup`. This is a part of the type system and checked statically, so it is
 ///     still an error to have such an edge in the CFG even if it's known that it won't be taken at
 ///     runtime.
-#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq)]
+#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, TypeFoldable, TypeVisitable)]
 pub enum TerminatorKind<'tcx> {
     /// Block has one successor; we continue execution there.
     Goto { target: BasicBlock },
@@ -705,7 +742,7 @@ pub enum TerminatorKind<'tcx> {
 }
 
 /// Information about an assertion failure.
-#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, PartialOrd)]
+#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, TypeFoldable, TypeVisitable)]
 pub enum AssertKind<O> {
     BoundsCheck { len: O, index: O },
     Overflow(BinOp, O, O),
@@ -793,6 +830,9 @@ pub type AssertMessage<'tcx> = AssertKind<Operand<'tcx>>;
 ///    generator has more than one variant, the parent place's variant index must be set, indicating
 ///    which variant is being used. If it has just one variant, the variant index may or may not be
 ///    included - the single possible variant is inferred if it is not included.
+///  - [`OpaqueCast`](ProjectionElem::OpaqueCast): This projection changes the place's type to the
+///    given one, and makes no other changes. A `OpaqueCast` projection on any type other than an
+///    opaque type from the current crate is not well-formed.
 ///  - [`ConstantIndex`](ProjectionElem::ConstantIndex): Computes an offset in units of `T` into the
 ///    place as described in the documentation for the `ProjectionElem`. The resulting address is
 ///    the parent's address plus that offset, and the type is `T`. This is only legal if the parent
@@ -827,7 +867,7 @@ pub type AssertMessage<'tcx> = AssertKind<Operand<'tcx>>;
 ///
 /// Rust currently requires that every place obey those two rules. This is checked by MIRI and taken
 /// advantage of by codegen (via `gep inbounds`). That is possibly subject to change.
-#[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, HashStable)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Place<'tcx> {
     pub local: Local,
 
@@ -836,7 +876,7 @@ pub struct Place<'tcx> {
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-#[derive(TyEncodable, TyDecodable, HashStable)]
+#[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
 pub enum ProjectionElem<V, T> {
     Deref,
     Field(Field, T),
@@ -892,6 +932,10 @@ pub enum ProjectionElem<V, T> {
     ///
     /// The included Symbol is the name of the variant, used for printing MIR.
     Downcast(Option<Symbol>, VariantIdx),
+
+    /// Like an explicit cast from an opaque type to a concrete type, but without
+    /// requiring an intermediate variable.
+    OpaqueCast(T),
 }
 
 /// Alias for projections as they appear in places, where the base is a place
@@ -919,7 +963,7 @@ pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
 /// **Needs clarifiation:** Is loading a place that has its variant index set well-formed? Miri
 /// currently implements it, but it seems like this may be something to check against in the
 /// validator.
-#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
+#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum Operand<'tcx> {
     /// Creates a value by loading the given place.
     ///
@@ -950,7 +994,7 @@ pub enum Operand<'tcx> {
 /// Computing any rvalue begins by evaluating the places and operands in some order (**Needs
 /// clarification**: Which order?). These are then used to produce a "value" - the same kind of
 /// value that an [`Operand`] produces.
-#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq)]
+#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, TypeFoldable, TypeVisitable)]
 pub enum Rvalue<'tcx> {
     /// Yields the operand unchanged
     Use(Operand<'tcx>),
@@ -1103,11 +1147,14 @@ pub enum CastKind {
     /// All sorts of pointer-to-pointer casts. Note that reference-to-raw-ptr casts are
     /// translated into `&raw mut/const *r`, i.e., they are not actually casts.
     Pointer(PointerCast),
+    /// Cast into a dyn* object.
+    DynStar,
     /// Remaining unclassified casts.
     Misc,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
 pub enum AggregateKind<'tcx> {
     /// The type is of the element
     Array(Ty<'tcx>),
@@ -1195,7 +1242,7 @@ pub enum BinOp {
 mod size_asserts {
     use super::*;
     // These are in alphabetical order, which is easy to maintain.
-    static_assert_size!(AggregateKind<'_>, 48);
+    static_assert_size!(AggregateKind<'_>, 40);
     static_assert_size!(Operand<'_>, 24);
     static_assert_size!(Place<'_>, 16);
     static_assert_size!(PlaceElem<'_>, 24);
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index 405003156c40..fa3adafd4b85 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -4,7 +4,6 @@
  */
 
 use crate::mir::*;
-use crate::ty::subst::Subst;
 use crate::ty::{self, Ty, TyCtxt};
 use rustc_hir as hir;
 use rustc_target::abi::VariantIdx;
@@ -57,7 +56,7 @@ impl<'tcx> PlaceTy<'tcx> {
     /// `PlaceElem`, where we can just use the `Ty` that is already
     /// stored inline on field projection elems.
     pub fn projection_ty(self, tcx: TyCtxt<'tcx>, elem: PlaceElem<'tcx>) -> PlaceTy<'tcx> {
-        self.projection_ty_core(tcx, ty::ParamEnv::empty(), &elem, |_, _, ty| ty)
+        self.projection_ty_core(tcx, ty::ParamEnv::empty(), &elem, |_, _, ty| ty, |_, ty| ty)
     }
 
     /// `place_ty.projection_ty_core(tcx, elem, |...| { ... })`
@@ -71,6 +70,7 @@ impl<'tcx> PlaceTy<'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         elem: &ProjectionElem<V, T>,
         mut handle_field: impl FnMut(&Self, Field, T) -> Ty<'tcx>,
+        mut handle_opaque_cast: impl FnMut(&Self, T) -> Ty<'tcx>,
     ) -> PlaceTy<'tcx>
     where
         V: ::std::fmt::Debug,
@@ -109,6 +109,7 @@ impl<'tcx> PlaceTy<'tcx> {
                 PlaceTy { ty: self.ty, variant_index: Some(index) }
             }
             ProjectionElem::Field(f, fty) => PlaceTy::from_ty(handle_field(&self, f, fty)),
+            ProjectionElem::OpaqueCast(ty) => PlaceTy::from_ty(handle_opaque_cast(&self, ty)),
         };
         debug!("projection_ty self: {:?} elem: {:?} yields: {:?}", self, elem, answer);
         answer
diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs
index 9ccf5aea63ca..4ea333cff7d9 100644
--- a/compiler/rustc_middle/src/mir/terminator.rs
+++ b/compiler/rustc_middle/src/mir/terminator.rs
@@ -14,7 +14,7 @@ use std::slice;
 
 pub use super::query::*;
 
-#[derive(Debug, Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, PartialOrd)]
+#[derive(Debug, Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq)]
 pub struct SwitchTargets {
     /// Possible values. The locations to branch to in each case
     /// are found in the corresponding indices from the `targets` vector.
@@ -102,7 +102,7 @@ impl<'a> Iterator for SwitchTargetsIter<'a> {
 
 impl<'a> ExactSizeIterator for SwitchTargetsIter<'a> {}
 
-#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
+#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Terminator<'tcx> {
     pub source_info: SourceInfo,
     pub kind: TerminatorKind<'tcx>,
diff --git a/compiler/rustc_middle/src/mir/type_foldable.rs b/compiler/rustc_middle/src/mir/type_foldable.rs
index 82a6b0c506f5..8e18cad442ed 100644
--- a/compiler/rustc_middle/src/mir/type_foldable.rs
+++ b/compiler/rustc_middle/src/mir/type_foldable.rs
@@ -1,8 +1,10 @@
 //! `TypeFoldable` implementations for MIR types
 
+use rustc_ast::InlineAsmTemplatePiece;
+
 use super::*;
+use crate::mir;
 use crate::ty;
-use rustc_data_structures::functor::IdFunctor;
 
 TrivialTypeTraversalAndLiftImpls! {
     BlockTailInfo,
@@ -13,96 +15,27 @@ TrivialTypeTraversalAndLiftImpls! {
     SourceScope,
     SourceScopeLocalData,
     UserTypeAnnotationIndex,
+    BorrowKind,
+    CastKind,
+    BinOp,
+    NullOp,
+    UnOp,
+    hir::Movability,
+    BasicBlock,
+    SwitchTargets,
+    GeneratorKind,
+    GeneratorSavedLocal,
 }
 
-impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        use crate::mir::TerminatorKind::*;
-
-        let kind = match self.kind {
-            Goto { target } => Goto { target },
-            SwitchInt { discr, switch_ty, targets } => SwitchInt {
-                discr: discr.try_fold_with(folder)?,
-                switch_ty: switch_ty.try_fold_with(folder)?,
-                targets,
-            },
-            Drop { place, target, unwind } => {
-                Drop { place: place.try_fold_with(folder)?, target, unwind }
-            }
-            DropAndReplace { place, value, target, unwind } => DropAndReplace {
-                place: place.try_fold_with(folder)?,
-                value: value.try_fold_with(folder)?,
-                target,
-                unwind,
-            },
-            Yield { value, resume, resume_arg, drop } => Yield {
-                value: value.try_fold_with(folder)?,
-                resume,
-                resume_arg: resume_arg.try_fold_with(folder)?,
-                drop,
-            },
-            Call { func, args, destination, target, cleanup, from_hir_call, fn_span } => Call {
-                func: func.try_fold_with(folder)?,
-                args: args.try_fold_with(folder)?,
-                destination: destination.try_fold_with(folder)?,
-                target,
-                cleanup,
-                from_hir_call,
-                fn_span,
-            },
-            Assert { cond, expected, msg, target, cleanup } => {
-                use AssertKind::*;
-                let msg = match msg {
-                    BoundsCheck { len, index } => BoundsCheck {
-                        len: len.try_fold_with(folder)?,
-                        index: index.try_fold_with(folder)?,
-                    },
-                    Overflow(op, l, r) => {
-                        Overflow(op, l.try_fold_with(folder)?, r.try_fold_with(folder)?)
-                    }
-                    OverflowNeg(op) => OverflowNeg(op.try_fold_with(folder)?),
-                    DivisionByZero(op) => DivisionByZero(op.try_fold_with(folder)?),
-                    RemainderByZero(op) => RemainderByZero(op.try_fold_with(folder)?),
-                    ResumedAfterReturn(_) | ResumedAfterPanic(_) => msg,
-                };
-                Assert { cond: cond.try_fold_with(folder)?, expected, msg, target, cleanup }
-            }
-            GeneratorDrop => GeneratorDrop,
-            Resume => Resume,
-            Abort => Abort,
-            Return => Return,
-            Unreachable => Unreachable,
-            FalseEdge { real_target, imaginary_target } => {
-                FalseEdge { real_target, imaginary_target }
-            }
-            FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
-            InlineAsm { template, operands, options, line_spans, destination, cleanup } => {
-                InlineAsm {
-                    template,
-                    operands: operands.try_fold_with(folder)?,
-                    options,
-                    line_spans,
-                    destination,
-                    cleanup,
-                }
-            }
-        };
-        Ok(Terminator { source_info: self.source_info, kind })
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for GeneratorKind {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _: &mut F) -> Result<Self, F::Error> {
+impl<'tcx> TypeFoldable<'tcx> for &'tcx [InlineAsmTemplatePiece] {
+    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _folder: &mut F) -> Result<Self, F::Error> {
         Ok(self)
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(Place {
-            local: self.local.try_fold_with(folder)?,
-            projection: self.projection.try_fold_with(folder)?,
-        })
+impl<'tcx> TypeFoldable<'tcx> for &'tcx [Span] {
+    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _folder: &mut F) -> Result<Self, F::Error> {
+        Ok(self)
     }
 }
 
@@ -112,110 +45,27 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        use crate::mir::Rvalue::*;
-        Ok(match self {
-            Use(op) => Use(op.try_fold_with(folder)?),
-            Repeat(op, len) => Repeat(op.try_fold_with(folder)?, len.try_fold_with(folder)?),
-            ThreadLocalRef(did) => ThreadLocalRef(did.try_fold_with(folder)?),
-            Ref(region, bk, place) => {
-                Ref(region.try_fold_with(folder)?, bk, place.try_fold_with(folder)?)
-            }
-            CopyForDeref(place) => CopyForDeref(place.try_fold_with(folder)?),
-            AddressOf(mutability, place) => AddressOf(mutability, place.try_fold_with(folder)?),
-            Len(place) => Len(place.try_fold_with(folder)?),
-            Cast(kind, op, ty) => Cast(kind, op.try_fold_with(folder)?, ty.try_fold_with(folder)?),
-            BinaryOp(op, box (rhs, lhs)) => {
-                BinaryOp(op, Box::new((rhs.try_fold_with(folder)?, lhs.try_fold_with(folder)?)))
-            }
-            CheckedBinaryOp(op, box (rhs, lhs)) => CheckedBinaryOp(
-                op,
-                Box::new((rhs.try_fold_with(folder)?, lhs.try_fold_with(folder)?)),
-            ),
-            UnaryOp(op, val) => UnaryOp(op, val.try_fold_with(folder)?),
-            Discriminant(place) => Discriminant(place.try_fold_with(folder)?),
-            NullaryOp(op, ty) => NullaryOp(op, ty.try_fold_with(folder)?),
-            Aggregate(kind, fields) => {
-                let kind = kind.try_map_id(|kind| {
-                    Ok(match kind {
-                        AggregateKind::Array(ty) => AggregateKind::Array(ty.try_fold_with(folder)?),
-                        AggregateKind::Tuple => AggregateKind::Tuple,
-                        AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
-                            def,
-                            v,
-                            substs.try_fold_with(folder)?,
-                            user_ty.try_fold_with(folder)?,
-                            n,
-                        ),
-                        AggregateKind::Closure(id, substs) => {
-                            AggregateKind::Closure(id, substs.try_fold_with(folder)?)
-                        }
-                        AggregateKind::Generator(id, substs, movablity) => {
-                            AggregateKind::Generator(id, substs.try_fold_with(folder)?, movablity)
-                        }
-                    })
-                })?;
-                Aggregate(kind, fields.try_fold_with(folder)?)
-            }
-            ShallowInitBox(op, ty) => {
-                ShallowInitBox(op.try_fold_with(folder)?, ty.try_fold_with(folder)?)
-            }
-        })
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(match self {
-            Operand::Copy(place) => Operand::Copy(place.try_fold_with(folder)?),
-            Operand::Move(place) => Operand::Move(place.try_fold_with(folder)?),
-            Operand::Constant(c) => Operand::Constant(c.try_fold_with(folder)?),
-        })
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        use crate::mir::ProjectionElem::*;
-
-        Ok(match self {
-            Deref => Deref,
-            Field(f, ty) => Field(f, ty.try_fold_with(folder)?),
-            Index(v) => Index(v.try_fold_with(folder)?),
-            Downcast(symbol, variantidx) => Downcast(symbol, variantidx),
-            ConstantIndex { offset, min_length, from_end } => {
-                ConstantIndex { offset, min_length, from_end }
-            }
-            Subslice { from, to, from_end } => Subslice { from, to, from_end },
-        })
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for Field {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _: &mut F) -> Result<Self, F::Error> {
-        Ok(self)
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _: &mut F) -> Result<Self, F::Error> {
-        Ok(self)
-    }
-}
-
 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _: &mut F) -> Result<Self, F::Error> {
         Ok(self)
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
+impl<'tcx> TypeFoldable<'tcx> for mir::UnevaluatedConst<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(Constant {
-            span: self.span,
-            user_ty: self.user_ty.try_fold_with(folder)?,
-            literal: self.literal.try_fold_with(folder)?,
+        folder.try_fold_mir_unevaluated(self)
+    }
+}
+
+impl<'tcx> TypeSuperFoldable<'tcx> for mir::UnevaluatedConst<'tcx> {
+    fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
+        self,
+        folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        Ok(mir::UnevaluatedConst {
+            def: self.def,
+            substs: self.substs.try_fold_with(folder)?,
+            promoted: self.promoted,
         })
     }
 }
@@ -235,6 +85,9 @@ impl<'tcx> TypeSuperFoldable<'tcx> for ConstantKind<'tcx> {
         match self {
             ConstantKind::Ty(c) => Ok(ConstantKind::Ty(c.try_fold_with(folder)?)),
             ConstantKind::Val(v, t) => Ok(ConstantKind::Val(v, t.try_fold_with(folder)?)),
+            ConstantKind::Unevaluated(uv, t) => {
+                Ok(ConstantKind::Unevaluated(uv.try_fold_with(folder)?, t.try_fold_with(folder)?))
+            }
         }
     }
 }
diff --git a/compiler/rustc_middle/src/mir/type_visitable.rs b/compiler/rustc_middle/src/mir/type_visitable.rs
index 6a0801cb0dd2..a136ca4d8c37 100644
--- a/compiler/rustc_middle/src/mir/type_visitable.rs
+++ b/compiler/rustc_middle/src/mir/type_visitable.rs
@@ -1,165 +1,7 @@
 //! `TypeVisitable` implementations for MIR types
 
 use super::*;
-use crate::ty;
-
-impl<'tcx> TypeVisitable<'tcx> for Terminator<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        use crate::mir::TerminatorKind::*;
-
-        match self.kind {
-            SwitchInt { ref discr, switch_ty, .. } => {
-                discr.visit_with(visitor)?;
-                switch_ty.visit_with(visitor)
-            }
-            Drop { ref place, .. } => place.visit_with(visitor),
-            DropAndReplace { ref place, ref value, .. } => {
-                place.visit_with(visitor)?;
-                value.visit_with(visitor)
-            }
-            Yield { ref value, .. } => value.visit_with(visitor),
-            Call { ref func, ref args, ref destination, .. } => {
-                destination.visit_with(visitor)?;
-                func.visit_with(visitor)?;
-                args.visit_with(visitor)
-            }
-            Assert { ref cond, ref msg, .. } => {
-                cond.visit_with(visitor)?;
-                use AssertKind::*;
-                match msg {
-                    BoundsCheck { ref len, ref index } => {
-                        len.visit_with(visitor)?;
-                        index.visit_with(visitor)
-                    }
-                    Overflow(_, l, r) => {
-                        l.visit_with(visitor)?;
-                        r.visit_with(visitor)
-                    }
-                    OverflowNeg(op) | DivisionByZero(op) | RemainderByZero(op) => {
-                        op.visit_with(visitor)
-                    }
-                    ResumedAfterReturn(_) | ResumedAfterPanic(_) => ControlFlow::CONTINUE,
-                }
-            }
-            InlineAsm { ref operands, .. } => operands.visit_with(visitor),
-            Goto { .. }
-            | Resume
-            | Abort
-            | Return
-            | GeneratorDrop
-            | Unreachable
-            | FalseEdge { .. }
-            | FalseUnwind { .. } => ControlFlow::CONTINUE,
-        }
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for GeneratorKind {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for Place<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.local.visit_with(visitor)?;
-        self.projection.visit_with(visitor)
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.iter().try_for_each(|t| t.visit_with(visitor))
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for Rvalue<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        use crate::mir::Rvalue::*;
-        match *self {
-            Use(ref op) => op.visit_with(visitor),
-            CopyForDeref(ref place) => {
-                let op = &Operand::Copy(*place);
-                op.visit_with(visitor)
-            }
-            Repeat(ref op, _) => op.visit_with(visitor),
-            ThreadLocalRef(did) => did.visit_with(visitor),
-            Ref(region, _, ref place) => {
-                region.visit_with(visitor)?;
-                place.visit_with(visitor)
-            }
-            AddressOf(_, ref place) => place.visit_with(visitor),
-            Len(ref place) => place.visit_with(visitor),
-            Cast(_, ref op, ty) => {
-                op.visit_with(visitor)?;
-                ty.visit_with(visitor)
-            }
-            BinaryOp(_, box (ref rhs, ref lhs)) | CheckedBinaryOp(_, box (ref rhs, ref lhs)) => {
-                rhs.visit_with(visitor)?;
-                lhs.visit_with(visitor)
-            }
-            UnaryOp(_, ref val) => val.visit_with(visitor),
-            Discriminant(ref place) => place.visit_with(visitor),
-            NullaryOp(_, ty) => ty.visit_with(visitor),
-            Aggregate(ref kind, ref fields) => {
-                match **kind {
-                    AggregateKind::Array(ty) => {
-                        ty.visit_with(visitor)?;
-                    }
-                    AggregateKind::Tuple => {}
-                    AggregateKind::Adt(_, _, substs, user_ty, _) => {
-                        substs.visit_with(visitor)?;
-                        user_ty.visit_with(visitor)?;
-                    }
-                    AggregateKind::Closure(_, substs) => {
-                        substs.visit_with(visitor)?;
-                    }
-                    AggregateKind::Generator(_, substs, _) => {
-                        substs.visit_with(visitor)?;
-                    }
-                }
-                fields.visit_with(visitor)
-            }
-            ShallowInitBox(ref op, ty) => {
-                op.visit_with(visitor)?;
-                ty.visit_with(visitor)
-            }
-        }
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for Operand<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        match *self {
-            Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
-            Operand::Constant(ref c) => c.visit_with(visitor),
-        }
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for PlaceElem<'tcx> {
-    fn visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> ControlFlow<Vs::BreakTy> {
-        use crate::mir::ProjectionElem::*;
-
-        match self {
-            Field(_, ty) => ty.visit_with(visitor),
-            Index(v) => v.visit_with(visitor),
-            _ => ControlFlow::CONTINUE,
-        }
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for Field {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for GeneratorSavedLocal {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
-    }
-}
+use crate::mir;
 
 impl<'tcx, R: Idx, C: Idx> TypeVisitable<'tcx> for BitMatrix<R, C> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
@@ -167,10 +9,15 @@ impl<'tcx, R: Idx, C: Idx> TypeVisitable<'tcx> for BitMatrix<R, C> {
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for Constant<'tcx> {
+impl<'tcx> TypeVisitable<'tcx> for mir::UnevaluatedConst<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.literal.visit_with(visitor)?;
-        self.user_ty.visit_with(visitor)
+        visitor.visit_mir_unevaluated(*self)
+    }
+}
+
+impl<'tcx> TypeSuperVisitable<'tcx> for mir::UnevaluatedConst<'tcx> {
+    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.substs.visit_with(visitor)
     }
 }
 
@@ -185,6 +32,10 @@ impl<'tcx> TypeSuperVisitable<'tcx> for ConstantKind<'tcx> {
         match *self {
             ConstantKind::Ty(c) => c.visit_with(visitor),
             ConstantKind::Val(_, t) => t.visit_with(visitor),
+            ConstantKind::Unevaluated(uv, t) => {
+                uv.visit_with(visitor)?;
+                t.visit_with(visitor)
+            }
         }
     }
 }
diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs
index 7bd65f42e3f9..ddcf3711bfc9 100644
--- a/compiler/rustc_middle/src/mir/visit.rs
+++ b/compiler/rustc_middle/src/mir/visit.rs
@@ -237,14 +237,6 @@ macro_rules! make_mir_visitor {
                 self.super_region(region);
             }
 
-            fn visit_const(
-                &mut self,
-                constant: $(& $mutability)? ty::Const<'tcx>,
-                _: Location,
-            ) {
-                self.super_const(constant);
-            }
-
             fn visit_substs(
                 &mut self,
                 substs: & $($mutability)? SubstsRef<'tcx>,
@@ -425,14 +417,15 @@ macro_rules! make_mir_visitor {
                             location
                         )
                     }
-                    StatementKind::CopyNonOverlapping(box crate::mir::CopyNonOverlapping{
-                        src,
-                        dst,
-                        count,
-                    }) => {
-                      self.visit_operand(src, location);
-                      self.visit_operand(dst, location);
-                      self.visit_operand(count, location)
+                    StatementKind::Intrinsic(box ref $($mutability)? intrinsic) => {
+                        match intrinsic {
+                            NonDivergingIntrinsic::Assume(op) => self.visit_operand(op, location),
+                            NonDivergingIntrinsic::CopyNonOverlapping(CopyNonOverlapping { src, dst, count }) => {
+                                self.visit_operand(src, location);
+                                self.visit_operand(dst, location);
+                                self.visit_operand(count, location);
+                            }
+                        }
                     }
                     StatementKind::Nop => {}
                 }
@@ -876,8 +869,9 @@ macro_rules! make_mir_visitor {
                 self.visit_span($(& $mutability)? *span);
                 drop(user_ty); // no visit method for this
                 match literal {
-                    ConstantKind::Ty(ct) => self.visit_const($(& $mutability)? *ct, location),
+                    ConstantKind::Ty(_) => {}
                     ConstantKind::Val(_, ty) => self.visit_ty($(& $mutability)? *ty, TyContext::Location(location)),
+                    ConstantKind::Unevaluated(_, ty) => self.visit_ty($(& $mutability)? *ty, TyContext::Location(location)),
                 }
             }
 
@@ -915,9 +909,6 @@ macro_rules! make_mir_visitor {
             fn super_region(&mut self, _region: $(& $mutability)? ty::Region<'tcx>) {
             }
 
-            fn super_const(&mut self, _const: $(& $mutability)? ty::Const<'tcx>) {
-            }
-
             fn super_substs(&mut self, _substs: & $($mutability)? SubstsRef<'tcx>) {
             }
 
@@ -1093,6 +1084,11 @@ macro_rules! visit_place_fns {
                     self.visit_ty(&mut new_ty, TyContext::Location(location));
                     if ty != new_ty { Some(PlaceElem::Field(field, new_ty)) } else { None }
                 }
+                PlaceElem::OpaqueCast(ty) => {
+                    let mut new_ty = ty;
+                    self.visit_ty(&mut new_ty, TyContext::Location(location));
+                    if ty != new_ty { Some(PlaceElem::OpaqueCast(new_ty)) } else { None }
+                }
                 PlaceElem::Deref
                 | PlaceElem::ConstantIndex { .. }
                 | PlaceElem::Subslice { .. }
@@ -1162,7 +1158,7 @@ macro_rules! visit_place_fns {
             location: Location,
         ) {
             match elem {
-                ProjectionElem::Field(_field, ty) => {
+                ProjectionElem::OpaqueCast(ty) | ProjectionElem::Field(_, ty) => {
                     self.visit_ty(ty, TyContext::Location(location));
                 }
                 ProjectionElem::Index(local) => {
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index ddca9820da1a..eed44240f835 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -47,14 +47,14 @@ rustc_queries! {
     /// To avoid this fate, do not call `tcx.hir().krate()`; instead,
     /// prefer wrappers like `tcx.visit_all_items_in_krate()`.
     query hir_crate(key: ()) -> Crate<'tcx> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "get the crate HIR" }
     }
 
     /// All items in the crate.
     query hir_crate_items(_: ()) -> rustc_middle::hir::ModuleItems {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "get HIR crate items" }
     }
@@ -64,7 +64,7 @@ rustc_queries! {
     /// This can be conveniently accessed by `tcx.hir().visit_item_likes_in_module`.
     /// Avoid calling this query directly.
     query hir_module_items(key: LocalDefId) -> rustc_middle::hir::ModuleItems {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "HIR module items in `{}`", tcx.def_path_str(key.to_def_id()) }
         cache_on_disk_if { true }
     }
@@ -73,7 +73,7 @@ rustc_queries! {
     ///
     /// This can be conveniently accessed by methods on `tcx.hir()`.
     /// Avoid calling this query directly.
-    query hir_owner(key: LocalDefId) -> Option<crate::hir::Owner<'tcx>> {
+    query hir_owner(key: hir::OwnerId) -> Option<crate::hir::Owner<'tcx>> {
         desc { |tcx| "HIR owner of `{}`", tcx.def_path_str(key.to_def_id()) }
     }
 
@@ -89,7 +89,7 @@ rustc_queries! {
     ///
     /// This can be conveniently accessed by methods on `tcx.hir()`.
     /// Avoid calling this query directly.
-    query hir_owner_parent(key: LocalDefId) -> hir::HirId {
+    query hir_owner_parent(key: hir::OwnerId) -> hir::HirId {
         desc { |tcx| "HIR parent of `{}`", tcx.def_path_str(key.to_def_id()) }
     }
 
@@ -97,7 +97,7 @@ rustc_queries! {
     ///
     /// This can be conveniently accessed by methods on `tcx.hir()`.
     /// Avoid calling this query directly.
-    query hir_owner_nodes(key: LocalDefId) -> hir::MaybeOwner<&'tcx hir::OwnerNodes<'tcx>> {
+    query hir_owner_nodes(key: hir::OwnerId) -> hir::MaybeOwner<&'tcx hir::OwnerNodes<'tcx>> {
         desc { |tcx| "HIR owner items in `{}`", tcx.def_path_str(key.to_def_id()) }
     }
 
@@ -105,7 +105,7 @@ rustc_queries! {
     ///
     /// This can be conveniently accessed by methods on `tcx.hir()`.
     /// Avoid calling this query directly.
-    query hir_attrs(key: LocalDefId) -> &'tcx hir::AttributeMap<'tcx> {
+    query hir_attrs(key: hir::OwnerId) -> &'tcx hir::AttributeMap<'tcx> {
         desc { |tcx| "HIR owner attributes in `{}`", tcx.def_path_str(key.to_def_id()) }
     }
 
@@ -161,6 +161,14 @@ rustc_queries! {
         separate_provide_extern
     }
 
+    query collect_trait_impl_trait_tys(key: DefId)
+        -> Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed>
+    {
+        desc { "compare an impl and trait method signature, inferring any hidden `impl Trait` types in the process" }
+        cache_on_disk_if { key.is_local() }
+        separate_provide_extern
+    }
+
     query analysis(key: ()) -> Result<(), ErrorGuaranteed> {
         eval_always
         desc { "running analysis passes on this crate" }
@@ -189,7 +197,7 @@ rustc_queries! {
     /// associated generics.
     query generics_of(key: DefId) -> ty::Generics {
         desc { |tcx| "computing generics of `{}`", tcx.def_path_str(key) }
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
@@ -261,13 +269,13 @@ rustc_queries! {
     }
 
     query native_libraries(_: CrateNum) -> Vec<NativeLib> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "looking up the native libraries of a linked crate" }
         separate_provide_extern
     }
 
     query lint_levels(_: ()) -> LintLevelMap {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "computing the lint levels for items in this crate" }
     }
@@ -300,7 +308,7 @@ rustc_queries! {
     /// Create a THIR tree for debugging.
     query thir_tree(key: ty::WithOptConstParam<LocalDefId>) -> String {
         no_hash
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "constructing THIR tree for `{}`", tcx.def_path_str(key.did.to_def_id()) }
     }
 
@@ -308,7 +316,7 @@ rustc_queries! {
     /// them. This includes all the body owners, but also things like struct
     /// constructors.
     query mir_keys(_: ()) -> rustc_data_structures::fx::FxIndexSet<LocalDefId> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "getting a list of all mir_keys" }
     }
 
@@ -369,7 +377,7 @@ rustc_queries! {
     }
 
     query try_unify_abstract_consts(key:
-        ty::ParamEnvAnd<'tcx, (ty::Unevaluated<'tcx, ()>, ty::Unevaluated<'tcx, ()>
+        ty::ParamEnvAnd<'tcx, (ty::UnevaluatedConst<'tcx>, ty::UnevaluatedConst<'tcx>
     )>) -> bool {
         desc {
             |tcx| "trying to unify the generic constants {} and {}",
@@ -415,7 +423,7 @@ rustc_queries! {
     query symbols_for_closure_captures(
         key: (LocalDefId, LocalDefId)
     ) -> Vec<rustc_span::Symbol> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc {
             |tcx| "symbols for captures of closure `{}` in `{}`",
             tcx.def_path_str(key.1.to_def_id()),
@@ -435,7 +443,7 @@ rustc_queries! {
     /// MIR pass (assuming the -Cinstrument-coverage option is enabled).
     query coverageinfo(key: ty::InstanceDef<'tcx>) -> mir::CoverageInfo {
         desc { |tcx| "retrieving coverage info from MIR for `{}`", tcx.def_path_str(key.def_id()) }
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
     }
 
     /// Returns the `CodeRegions` for a function that has instrumented coverage, in case the
@@ -445,7 +453,7 @@ rustc_queries! {
             |tcx| "retrieving the covered `CodeRegion`s, if instrumented, for `{}`",
             tcx.def_path_str(key)
         }
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         cache_on_disk_if { key.is_local() }
     }
 
@@ -483,7 +491,7 @@ rustc_queries! {
     }
 
     query wasm_import_module_map(_: CrateNum) -> FxHashMap<DefId, String> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "wasm import module map" }
     }
 
@@ -559,7 +567,7 @@ rustc_queries! {
 
     query trait_def(key: DefId) -> ty::TraitDef {
         desc { |tcx| "computing trait definition for `{}`", tcx.def_path_str(key) }
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
@@ -637,7 +645,7 @@ rustc_queries! {
 
     /// Gets a map with the variance of every item; use `item_variance` instead.
     query crate_variances(_: ()) -> ty::CrateVariancesMap<'tcx> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "computing the variances for items in this crate" }
     }
 
@@ -650,7 +658,7 @@ rustc_queries! {
 
     /// Maps from thee `DefId` of a type to its (inferred) outlives.
     query inferred_outlives_crate(_: ()) -> ty::CratePredicatesMap<'tcx> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "computing the inferred outlives predicates for items in this crate" }
     }
 
@@ -664,14 +672,14 @@ rustc_queries! {
     /// Maps from a trait item to the trait item "descriptor".
     query associated_item(key: DefId) -> ty::AssocItem {
         desc { |tcx| "computing associated item data for `{}`", tcx.def_path_str(key) }
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
 
     /// Collects the associated items defined on a trait or impl.
     query associated_items(key: DefId) -> ty::AssocItems<'tcx> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "collecting associated items of {}", tcx.def_path_str(key) }
     }
 
@@ -697,7 +705,7 @@ rustc_queries! {
     /// The map returned for `tcx.impl_item_implementor_ids(impl_id)` would be
     ///`{ trait_f: impl_f, trait_g: impl_g }`
     query impl_item_implementor_ids(impl_id: DefId) -> FxHashMap<DefId, DefId> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "comparing impl items against trait for {}", tcx.def_path_str(impl_id) }
     }
 
@@ -830,7 +838,7 @@ rustc_queries! {
         FxHashSet<LocalDefId>,
         FxHashMap<LocalDefId, Vec<(DefId, DefId)>>
     ) {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "find live symbols in crate" }
     }
 
@@ -876,13 +884,6 @@ rustc_queries! {
     query diagnostic_only_typeck(key: LocalDefId) -> &'tcx ty::TypeckResults<'tcx> {
         desc { |tcx| "type-checking `{}`", tcx.def_path_str(key.to_def_id()) }
         cache_on_disk_if { true }
-        load_cached(tcx, id) {
-            let typeck_results: Option<ty::TypeckResults<'tcx>> = tcx
-                .on_disk_cache().as_ref()
-                .and_then(|c| c.try_load_query_result(*tcx, id));
-
-            typeck_results.map(|x| &*tcx.arena.alloc(x))
-        }
     }
 
     query used_trait_imports(key: LocalDefId) -> &'tcx FxHashSet<LocalDefId> {
@@ -914,7 +915,7 @@ rustc_queries! {
     /// Gets a complete map from all types to their inherent impls.
     /// Not meant to be used directly outside of coherence.
     query crate_inherent_impls(k: ()) -> CrateInherentImpls {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "all inherent impls defined in crate" }
     }
 
@@ -1002,7 +1003,9 @@ rustc_queries! {
 
     /// Tries to destructure an `mir::ConstantKind` ADT or array into its variant index
     /// and its field values.
-    query try_destructure_mir_constant(key: ty::ParamEnvAnd<'tcx, mir::ConstantKind<'tcx>>) -> Option<mir::DestructuredMirConstant<'tcx>> {
+    query try_destructure_mir_constant(
+        key: ty::ParamEnvAnd<'tcx, mir::ConstantKind<'tcx>>
+    ) -> Option<mir::DestructuredConstant<'tcx>> {
         desc { "destructuring mir constant"}
         remap_env_constness
     }
@@ -1047,7 +1050,7 @@ rustc_queries! {
     }
 
     query reachable_set(_: ()) -> FxHashSet<LocalDefId> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "reachability" }
     }
 
@@ -1059,7 +1062,7 @@ rustc_queries! {
 
     /// Generates a MIR body for the shim.
     query mir_shims(key: ty::InstanceDef<'tcx>) -> mir::Body<'tcx> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "generating MIR shim for `{}`", tcx.def_path_str(key.def_id()) }
     }
 
@@ -1133,7 +1136,7 @@ rustc_queries! {
 
     query codegen_fn_attrs(def_id: DefId) -> CodegenFnAttrs {
         desc { |tcx| "computing codegen attributes of `{}`", tcx.def_path_str(def_id) }
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         cache_on_disk_if { def_id.is_local() }
         separate_provide_extern
     }
@@ -1150,8 +1153,8 @@ rustc_queries! {
     /// Gets the rendered value of the specified constant or associated constant.
     /// Used by rustdoc.
     query rendered_const(def_id: DefId) -> String {
-        storage(ArenaCacheSelector<'tcx>)
-        desc { |tcx| "rendering constant intializer of `{}`", tcx.def_path_str(def_id) }
+        arena_cache
+        desc { |tcx| "rendering constant initializer of `{}`", tcx.def_path_str(def_id) }
         cache_on_disk_if { def_id.is_local() }
         separate_provide_extern
     }
@@ -1195,14 +1198,11 @@ rustc_queries! {
         }
     }
 
-    query codegen_fulfill_obligation(
+    query codegen_select_candidate(
         key: (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>)
     ) -> Result<&'tcx ImplSource<'tcx, ()>, traits::CodegenObligationError> {
         cache_on_disk_if { true }
-        desc { |tcx|
-            "checking if `{}` fulfills its obligations",
-            tcx.def_path_str(key.1.def_id())
-        }
+        desc { |tcx| "computing candidate for `{}`", key.1 }
     }
 
     /// Return all `impl` blocks in the current crate.
@@ -1212,12 +1212,12 @@ rustc_queries! {
 
     /// Given a trait `trait_id`, return all known `impl` blocks.
     query trait_impls_of(trait_id: DefId) -> ty::trait_def::TraitImpls {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "trait impls of `{}`", tcx.def_path_str(trait_id) }
     }
 
     query specialization_graph_of(trait_id: DefId) -> specialization_graph::Graph {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "building specialization graph of trait `{}`", tcx.def_path_str(trait_id) }
         cache_on_disk_if { true }
     }
@@ -1344,7 +1344,7 @@ rustc_queries! {
     }
 
     query dependency_formats(_: ()) -> Lrc<crate::middle::dependency_format::Dependencies> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "get the linkage format of all dependencies" }
     }
 
@@ -1404,7 +1404,7 @@ rustc_queries! {
     query specializes(_: (DefId, DefId)) -> bool {
         desc { "computing whether impls specialize one another" }
     }
-    query in_scope_traits_map(_: LocalDefId)
+    query in_scope_traits_map(_: hir::OwnerId)
         -> Option<&'tcx FxHashMap<ItemLocalId, Box<[TraitCandidate]>>> {
         desc { "traits in scope at a block" }
     }
@@ -1419,7 +1419,7 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    query check_well_formed(key: LocalDefId) -> () {
+    query check_well_formed(key: hir::OwnerId) -> () {
         desc { |tcx| "checking that `{}` is well-formed", tcx.def_path_str(key.to_def_id()) }
     }
 
@@ -1437,7 +1437,7 @@ rustc_queries! {
     // like the compiler-generated `main` function and so on.
     query reachable_non_generics(_: CrateNum)
         -> DefIdMap<SymbolExportInfo> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "looking up the exported symbols of a crate" }
         separate_provide_extern
     }
@@ -1460,7 +1460,7 @@ rustc_queries! {
     /// `upstream_monomorphizations_for`, `upstream_drop_glue_for`, or, even
     /// better, `Instance::upstream_monomorphization()`.
     query upstream_monomorphizations(_: ()) -> DefIdMap<FxHashMap<SubstsRef<'tcx>, CrateNum>> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "collecting available upstream monomorphizations" }
     }
 
@@ -1474,7 +1474,7 @@ rustc_queries! {
     query upstream_monomorphizations_for(def_id: DefId)
         -> Option<&'tcx FxHashMap<SubstsRef<'tcx>, CrateNum>>
     {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx|
             "collecting available upstream monomorphizations for `{}`",
             tcx.def_path_str(def_id),
@@ -1502,7 +1502,7 @@ rustc_queries! {
     }
 
     query foreign_modules(_: CrateNum) -> FxHashMap<DefId, ForeignModule> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "looking up the foreign modules of a linked crate" }
         separate_provide_extern
     }
@@ -1528,13 +1528,13 @@ rustc_queries! {
         separate_provide_extern
     }
     query extra_filename(_: CrateNum) -> String {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "looking up the extra filename for a crate" }
         separate_provide_extern
     }
     query crate_extern_paths(_: CrateNum) -> Vec<PathBuf> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "looking up the paths for extern crates" }
         separate_provide_extern
@@ -1576,37 +1576,48 @@ rustc_queries! {
     /// the same lifetimes and is responsible for diagnostics.
     /// See `rustc_resolve::late::lifetimes for details.
     query resolve_lifetimes_trait_definition(_: LocalDefId) -> ResolveLifetimes {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "resolving lifetimes for a trait definition" }
     }
     /// Does lifetime resolution on items. Importantly, we can't resolve
     /// lifetimes directly on things like trait methods, because of trait params.
     /// See `rustc_resolve::late::lifetimes for details.
     query resolve_lifetimes(_: LocalDefId) -> ResolveLifetimes {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "resolving lifetimes" }
     }
-    query named_region_map(_: LocalDefId) ->
+    query named_region_map(_: hir::OwnerId) ->
         Option<&'tcx FxHashMap<ItemLocalId, Region>> {
         desc { "looking up a named region" }
     }
     query is_late_bound_map(_: LocalDefId) -> Option<&'tcx FxIndexSet<LocalDefId>> {
         desc { "testing if a region is late bound" }
     }
-    /// For a given item (like a struct), gets the default lifetimes to be used
+    /// For a given item's generic parameter, gets the default lifetimes to be used
     /// for each parameter if a trait object were to be passed for that parameter.
-    /// For example, for `struct Foo<'a, T, U>`, this would be `['static, 'static]`.
-    /// For `struct Foo<'a, T: 'a, U>`, this would instead be `['a, 'static]`.
-    query object_lifetime_default(key: DefId) -> Option<ObjectLifetimeDefault> {
-        desc { "looking up lifetime defaults for generic parameter `{:?}`", key }
+    /// For example, for `T` in `struct Foo<'a, T>`, this would be `'static`.
+    /// For `T` in `struct Foo<'a, T: 'a>`, this would instead be `'a`.
+    /// This query will panic if passed something that is not a type parameter.
+    query object_lifetime_default(key: DefId) -> ObjectLifetimeDefault {
+        desc { "looking up lifetime defaults for generic parameter `{}`", tcx.def_path_str(key) }
         separate_provide_extern
     }
-    query late_bound_vars_map(_: LocalDefId)
+    query late_bound_vars_map(_: hir::OwnerId)
         -> Option<&'tcx FxHashMap<ItemLocalId, Vec<ty::BoundVariableKind>>> {
         desc { "looking up late bound vars" }
     }
 
-    query visibility(def_id: DefId) -> ty::Visibility {
+    /// Computes the visibility of the provided `def_id`.
+    ///
+    /// If the item from the `def_id` doesn't have a visibility, it will panic. For example
+    /// a generic type parameter will panic if you call this method on it:
+    ///
+    /// ```
+    /// pub trait Foo<T: Debug> {}
+    /// ```
+    ///
+    /// In here, if you call `visibility` on `T`, it'll panic.
+    query visibility(def_id: DefId) -> ty::Visibility<DefId> {
         desc { |tcx| "computing visibility of `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern
     }
@@ -1642,7 +1653,7 @@ rustc_queries! {
     }
 
     query lib_features(_: ()) -> LibFeatures {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "calculating the lib features map" }
     }
     query defined_lib_features(_: CrateNum) -> &'tcx [(Symbol, Option<Symbol>)] {
@@ -1650,7 +1661,7 @@ rustc_queries! {
         separate_provide_extern
     }
     query stability_implications(_: CrateNum) -> FxHashMap<Symbol, Symbol> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "calculating the implications between `#[unstable]` features defined in a crate" }
         separate_provide_extern
     }
@@ -1661,14 +1672,14 @@ rustc_queries! {
     }
     /// Returns the lang items defined in another crate by loading it from metadata.
     query get_lang_items(_: ()) -> LanguageItems {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "calculating the lang items map" }
     }
 
     /// Returns all diagnostic items defined in all crates.
     query all_diagnostic_items(_: ()) -> rustc_hir::diagnostic_items::DiagnosticItems {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "calculating the diagnostic items map" }
     }
@@ -1681,7 +1692,7 @@ rustc_queries! {
 
     /// Returns the diagnostic items defined in a crate.
     query diagnostic_items(_: CrateNum) -> rustc_hir::diagnostic_items::DiagnosticItems {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "calculating the diagnostic items map in a crate" }
         separate_provide_extern
     }
@@ -1691,11 +1702,11 @@ rustc_queries! {
         separate_provide_extern
     }
     query visible_parent_map(_: ()) -> DefIdMap<DefId> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "calculating the visible parent map" }
     }
     query trimmed_def_paths(_: ()) -> FxHashMap<DefId, Symbol> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "calculating trimmed def paths" }
     }
     query missing_extern_crate_item(_: CrateNum) -> bool {
@@ -1704,14 +1715,14 @@ rustc_queries! {
         separate_provide_extern
     }
     query used_crate_source(_: CrateNum) -> Lrc<CrateSource> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "looking at the source for a crate" }
         separate_provide_extern
     }
     /// Returns the debugger visualizers defined for this crate.
     query debugger_visualizers(_: CrateNum) -> Vec<rustc_span::DebuggerVisualizerFile> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { "looking up the debugger visualizers for this crate" }
         separate_provide_extern
     }
@@ -1745,7 +1756,7 @@ rustc_queries! {
     }
 
     query stability_index(_: ()) -> stability::Index {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "calculating the stability index for the local crate" }
     }
@@ -1986,7 +1997,7 @@ rustc_queries! {
     }
 
     query supported_target_features(_: CrateNum) -> FxHashMap<String, Option<Symbol>> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "looking up supported target features" }
     }
@@ -2056,7 +2067,7 @@ rustc_queries! {
     /// all of the cases that the normal `ty::Ty`-based wfcheck does. This is fine,
     /// because the `ty::Ty`-based wfcheck is always run.
     query diagnostic_hir_wf_check(key: (ty::Predicate<'tcx>, traits::WellFormedLoc)) -> Option<traits::ObligationCause<'tcx>> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         no_hash
         desc { "performing HIR wf-checking for predicate {:?} at item {:?}", key.0, key.1 }
@@ -2066,13 +2077,13 @@ rustc_queries! {
     /// The list of backend features computed from CLI flags (`-Ctarget-cpu`, `-Ctarget-feature`,
     /// `--target` and similar).
     query global_backend_features(_: ()) -> Vec<String> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         eval_always
         desc { "computing the backend features for CLI flags" }
     }
 
     query generator_diagnostic_data(key: DefId) -> Option<GeneratorDiagnosticData<'tcx>> {
-        storage(ArenaCacheSelector<'tcx>)
+        arena_cache
         desc { |tcx| "looking up generator diagnostic data of `{}`", tcx.def_path_str(key) }
         separate_provide_extern
     }
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index 0f2504e3d9af..84374a25ed85 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -23,7 +23,7 @@ use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, AdtDef, Ty, UpvarSubsts};
 use rustc_middle::ty::{CanonicalUserType, CanonicalUserTypeAnnotation};
 use rustc_span::def_id::LocalDefId;
-use rustc_span::{Span, Symbol, DUMMY_SP};
+use rustc_span::{sym, Span, Symbol, DUMMY_SP};
 use rustc_target::abi::VariantIdx;
 use rustc_target::asm::InlineAsmRegOrRegClass;
 use std::fmt;
@@ -73,11 +73,29 @@ macro_rules! thir_with_elements {
     }
 }
 
+pub const UPVAR_ENV_PARAM: ParamId = ParamId::from_u32(0);
+
 thir_with_elements! {
     arms: ArmId => Arm<'tcx> => "a{}",
     blocks: BlockId => Block => "b{}",
     exprs: ExprId => Expr<'tcx> => "e{}",
     stmts: StmtId => Stmt<'tcx> => "s{}",
+    params: ParamId => Param<'tcx> => "p{}",
+}
+
+/// Description of a type-checked function parameter.
+#[derive(Clone, Debug, HashStable)]
+pub struct Param<'tcx> {
+    /// The pattern that appears in the parameter list, or None for implicit parameters.
+    pub pat: Option<Box<Pat<'tcx>>>,
+    /// The possibly inferred type.
+    pub ty: Ty<'tcx>,
+    /// Span of the explicitly provided type, or None if inferred for closures.
+    pub ty_span: Option<Span>,
+    /// Whether this param is `self`, and how it is bound.
+    pub self_kind: Option<hir::ImplicitSelfKind>,
+    /// HirId for lints.
+    pub hir_id: Option<hir::HirId>,
 }
 
 #[derive(Copy, Clone, Debug, HashStable)]
@@ -180,7 +198,7 @@ pub enum StmtKind<'tcx> {
         /// `let <PAT> = ...`
         ///
         /// If a type annotation is included, it is added as an ascription pattern.
-        pattern: Pat<'tcx>,
+        pattern: Box<Pat<'tcx>>,
 
         /// `let pat: ty = <INIT>`
         initializer: Option<ExprId>,
@@ -301,7 +319,7 @@ pub enum ExprKind<'tcx> {
     },
     Let {
         expr: ExprId,
-        pat: Pat<'tcx>,
+        pat: Box<Pat<'tcx>>,
     },
     /// A `match` expression.
     Match {
@@ -467,7 +485,7 @@ pub struct FruInfo<'tcx> {
 /// A `match` arm.
 #[derive(Clone, Debug, HashStable)]
 pub struct Arm<'tcx> {
-    pub pattern: Pat<'tcx>,
+    pub pattern: Box<Pat<'tcx>>,
     pub guard: Option<Guard<'tcx>>,
     pub body: ExprId,
     pub lint_level: LintLevel,
@@ -479,7 +497,7 @@ pub struct Arm<'tcx> {
 #[derive(Clone, Debug, HashStable)]
 pub enum Guard<'tcx> {
     If(ExprId),
-    IfLet(Pat<'tcx>, ExprId),
+    IfLet(Box<Pat<'tcx>>, ExprId),
 }
 
 #[derive(Copy, Clone, Debug, HashStable)]
@@ -534,19 +552,28 @@ pub enum BindingMode {
 #[derive(Clone, Debug, HashStable)]
 pub struct FieldPat<'tcx> {
     pub field: Field,
-    pub pattern: Pat<'tcx>,
+    pub pattern: Box<Pat<'tcx>>,
 }
 
 #[derive(Clone, Debug, HashStable)]
 pub struct Pat<'tcx> {
     pub ty: Ty<'tcx>,
     pub span: Span,
-    pub kind: Box<PatKind<'tcx>>,
+    pub kind: PatKind<'tcx>,
 }
 
 impl<'tcx> Pat<'tcx> {
     pub fn wildcard_from_ty(ty: Ty<'tcx>) -> Self {
-        Pat { ty, span: DUMMY_SP, kind: Box::new(PatKind::Wild) }
+        Pat { ty, span: DUMMY_SP, kind: PatKind::Wild }
+    }
+
+    pub fn simple_ident(&self) -> Option<Symbol> {
+        match self.kind {
+            PatKind::Binding { name, mode: BindingMode::ByValue, subpattern: None, .. } => {
+                Some(name)
+            }
+            _ => None,
+        }
     }
 }
 
@@ -581,7 +608,7 @@ pub enum PatKind<'tcx> {
 
     AscribeUserType {
         ascription: Ascription<'tcx>,
-        subpattern: Pat<'tcx>,
+        subpattern: Box<Pat<'tcx>>,
     },
 
     /// `x`, `ref x`, `x @ P`, etc.
@@ -591,7 +618,7 @@ pub enum PatKind<'tcx> {
         mode: BindingMode,
         var: LocalVarId,
         ty: Ty<'tcx>,
-        subpattern: Option<Pat<'tcx>>,
+        subpattern: Option<Box<Pat<'tcx>>>,
         /// Is this the leftmost occurrence of the binding, i.e., is `var` the
         /// `HirId` of this pattern?
         is_primary: bool,
@@ -614,7 +641,7 @@ pub enum PatKind<'tcx> {
 
     /// `box P`, `&P`, `&mut P`, etc.
     Deref {
-        subpattern: Pat<'tcx>,
+        subpattern: Box<Pat<'tcx>>,
     },
 
     /// One of the following:
@@ -628,32 +655,32 @@ pub enum PatKind<'tcx> {
         value: mir::ConstantKind<'tcx>,
     },
 
-    Range(PatRange<'tcx>),
+    Range(Box<PatRange<'tcx>>),
 
     /// Matches against a slice, checking the length and extracting elements.
     /// irrefutable when there is a slice pattern and both `prefix` and `suffix` are empty.
     /// e.g., `&[ref xs @ ..]`.
     Slice {
-        prefix: Vec<Pat<'tcx>>,
-        slice: Option<Pat<'tcx>>,
-        suffix: Vec<Pat<'tcx>>,
+        prefix: Box<[Box<Pat<'tcx>>]>,
+        slice: Option<Box<Pat<'tcx>>>,
+        suffix: Box<[Box<Pat<'tcx>>]>,
     },
 
     /// Fixed match against an array; irrefutable.
     Array {
-        prefix: Vec<Pat<'tcx>>,
-        slice: Option<Pat<'tcx>>,
-        suffix: Vec<Pat<'tcx>>,
+        prefix: Box<[Box<Pat<'tcx>>]>,
+        slice: Option<Box<Pat<'tcx>>>,
+        suffix: Box<[Box<Pat<'tcx>>]>,
     },
 
     /// An or-pattern, e.g. `p | q`.
     /// Invariant: `pats.len() >= 2`.
     Or {
-        pats: Vec<Pat<'tcx>>,
+        pats: Box<[Box<Pat<'tcx>>]>,
     },
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, HashStable)]
+#[derive(Clone, Debug, PartialEq, HashStable)]
 pub struct PatRange<'tcx> {
     pub lo: mir::ConstantKind<'tcx>,
     pub hi: mir::ConstantKind<'tcx>,
@@ -674,7 +701,7 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
         };
         let mut start_or_comma = || start_or_continue(", ");
 
-        match *self.kind {
+        match self.kind {
             PatKind::Wild => write!(f, "_"),
             PatKind::AscribeUserType { ref subpattern, .. } => write!(f, "{}: _", subpattern),
             PatKind::Binding { mutability, name, mode, ref subpattern, .. } => {
@@ -695,17 +722,32 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
                 Ok(())
             }
             PatKind::Variant { ref subpatterns, .. } | PatKind::Leaf { ref subpatterns } => {
-                let variant = match *self.kind {
-                    PatKind::Variant { adt_def, variant_index, .. } => {
-                        Some(adt_def.variant(variant_index))
-                    }
-                    _ => self.ty.ty_adt_def().and_then(|adt| {
-                        if !adt.is_enum() { Some(adt.non_enum_variant()) } else { None }
+                let variant_and_name = match self.kind {
+                    PatKind::Variant { adt_def, variant_index, .. } => ty::tls::with(|tcx| {
+                        let variant = adt_def.variant(variant_index);
+                        let adt_did = adt_def.did();
+                        let name = if tcx.get_diagnostic_item(sym::Option) == Some(adt_did)
+                            || tcx.get_diagnostic_item(sym::Result) == Some(adt_did)
+                        {
+                            variant.name.to_string()
+                        } else {
+                            format!("{}::{}", tcx.def_path_str(adt_def.did()), variant.name)
+                        };
+                        Some((variant, name))
+                    }),
+                    _ => self.ty.ty_adt_def().and_then(|adt_def| {
+                        if !adt_def.is_enum() {
+                            ty::tls::with(|tcx| {
+                                Some((adt_def.non_enum_variant(), tcx.def_path_str(adt_def.did())))
+                            })
+                        } else {
+                            None
+                        }
                     }),
                 };
 
-                if let Some(variant) = variant {
-                    write!(f, "{}", variant.name)?;
+                if let Some((variant, name)) = &variant_and_name {
+                    write!(f, "{}", name)?;
 
                     // Only for Adt we can have `S {...}`,
                     // which we handle separately here.
@@ -714,7 +756,7 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
 
                         let mut printed = 0;
                         for p in subpatterns {
-                            if let PatKind::Wild = *p.pattern.kind {
+                            if let PatKind::Wild = p.pattern.kind {
                                 continue;
                             }
                             let name = variant.fields[p.field.index()].name;
@@ -730,8 +772,9 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
                     }
                 }
 
-                let num_fields = variant.map_or(subpatterns.len(), |v| v.fields.len());
-                if num_fields != 0 || variant.is_none() {
+                let num_fields =
+                    variant_and_name.as_ref().map_or(subpatterns.len(), |(v, _)| v.fields.len());
+                if num_fields != 0 || variant_and_name.is_none() {
                     write!(f, "(")?;
                     for i in 0..num_fields {
                         write!(f, "{}", start_or_comma())?;
@@ -767,7 +810,7 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
                 write!(f, "{}", subpattern)
             }
             PatKind::Constant { value } => write!(f, "{}", value),
-            PatKind::Range(PatRange { lo, hi, end }) => {
+            PatKind::Range(box PatRange { lo, hi, end }) => {
                 write!(f, "{}", lo)?;
                 write!(f, "{}", end)?;
                 write!(f, "{}", hi)
@@ -775,24 +818,24 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
             PatKind::Slice { ref prefix, ref slice, ref suffix }
             | PatKind::Array { ref prefix, ref slice, ref suffix } => {
                 write!(f, "[")?;
-                for p in prefix {
+                for p in prefix.iter() {
                     write!(f, "{}{}", start_or_comma(), p)?;
                 }
                 if let Some(ref slice) = *slice {
                     write!(f, "{}", start_or_comma())?;
-                    match *slice.kind {
+                    match slice.kind {
                         PatKind::Wild => {}
                         _ => write!(f, "{}", slice)?,
                     }
                     write!(f, "..")?;
                 }
-                for p in suffix {
+                for p in suffix.iter() {
                     write!(f, "{}{}", start_or_comma(), p)?;
                 }
                 write!(f, "]")
             }
             PatKind::Or { ref pats } => {
-                for pat in pats {
+                for pat in pats.iter() {
                     write!(f, "{}{}", start_or_continue(" | "), pat)?;
                 }
                 Ok(())
@@ -809,8 +852,8 @@ mod size_asserts {
     static_assert_size!(Block, 56);
     static_assert_size!(Expr<'_>, 64);
     static_assert_size!(ExprKind<'_>, 40);
-    static_assert_size!(Pat<'_>, 24);
-    static_assert_size!(PatKind<'_>, 112);
-    static_assert_size!(Stmt<'_>, 72);
-    static_assert_size!(StmtKind<'_>, 64);
+    static_assert_size!(Pat<'_>, 72);
+    static_assert_size!(PatKind<'_>, 56);
+    static_assert_size!(Stmt<'_>, 48);
+    static_assert_size!(StmtKind<'_>, 40);
 }
diff --git a/compiler/rustc_middle/src/thir/visit.rs b/compiler/rustc_middle/src/thir/visit.rs
index c5c48a636092..79a0e75aa7c7 100644
--- a/compiler/rustc_middle/src/thir/visit.rs
+++ b/compiler/rustc_middle/src/thir/visit.rs
@@ -211,7 +211,7 @@ pub fn walk_arm<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, arm: &Arm<'
 
 pub fn walk_pat<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, pat: &Pat<'tcx>) {
     use PatKind::*;
-    match pat.kind.as_ref() {
+    match &pat.kind {
         AscribeUserType { subpattern, ascription: _ }
         | Deref { subpattern }
         | Binding {
@@ -232,18 +232,18 @@ pub fn walk_pat<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, pat: &Pat<'
         Constant { value: _ } => {}
         Range(_) => {}
         Slice { prefix, slice, suffix } | Array { prefix, slice, suffix } => {
-            for subpattern in prefix {
+            for subpattern in prefix.iter() {
                 visitor.visit_pat(&subpattern);
             }
             if let Some(pat) = slice {
-                visitor.visit_pat(pat);
+                visitor.visit_pat(&pat);
             }
-            for subpattern in suffix {
+            for subpattern in suffix.iter() {
                 visitor.visit_pat(&subpattern);
             }
         }
         Or { pats } => {
-            for pat in pats {
+            for pat in pats.iter() {
                 visitor.visit_pat(&pat);
             }
         }
diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index ab7e5ba3a106..68a7af0b8c8d 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -10,9 +10,10 @@ mod structural_impls;
 pub mod util;
 
 use crate::infer::canonical::Canonical;
+use crate::mir::ConstraintCategory;
 use crate::ty::abstract_const::NotConstEvaluatable;
 use crate::ty::subst::SubstsRef;
-use crate::ty::{self, AdtKind, Predicate, Ty, TyCtxt};
+use crate::ty::{self, AdtKind, Ty, TyCtxt};
 
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{Applicability, Diagnostic};
@@ -183,6 +184,16 @@ impl<'tcx> ObligationCause<'tcx> {
             variant(DerivedObligationCause { parent_trait_pred, parent_code: self.code }).into();
         self
     }
+
+    pub fn to_constraint_category(&self) -> ConstraintCategory<'tcx> {
+        match self.code() {
+            MatchImpl(cause, _) => cause.to_constraint_category(),
+            AscribeUserTypeProvePredicate(predicate_span) => {
+                ConstraintCategory::Predicate(*predicate_span)
+            }
+            _ => ConstraintCategory::BoringNoLocation,
+        }
+    }
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Lift)]
@@ -416,8 +427,10 @@ pub enum ObligationCauseCode<'tcx> {
     BinOp {
         rhs_span: Option<Span>,
         is_lit: bool,
-        output_pred: Option<Predicate<'tcx>>,
+        output_ty: Option<Ty<'tcx>>,
     },
+
+    AscribeUserTypeProvePredicate(Span),
 }
 
 /// The 'location' at which we try to perform HIR-based wf checking.
@@ -651,6 +664,10 @@ pub enum ImplSource<'tcx, N> {
 
     /// ImplSource for a `const Drop` implementation.
     ConstDestruct(ImplSourceConstDestructData<N>),
+
+    /// ImplSource for a `std::marker::Tuple` implementation.
+    /// This has no nested predicates ever, so no data.
+    Tuple,
 }
 
 impl<'tcx, N> ImplSource<'tcx, N> {
@@ -665,7 +682,8 @@ impl<'tcx, N> ImplSource<'tcx, N> {
             ImplSource::Object(d) => d.nested,
             ImplSource::FnPointer(d) => d.nested,
             ImplSource::DiscriminantKind(ImplSourceDiscriminantKindData)
-            | ImplSource::Pointee(ImplSourcePointeeData) => Vec::new(),
+            | ImplSource::Pointee(ImplSourcePointeeData)
+            | ImplSource::Tuple => Vec::new(),
             ImplSource::TraitAlias(d) => d.nested,
             ImplSource::TraitUpcasting(d) => d.nested,
             ImplSource::ConstDestruct(i) => i.nested,
@@ -683,7 +701,8 @@ impl<'tcx, N> ImplSource<'tcx, N> {
             ImplSource::Object(d) => &d.nested,
             ImplSource::FnPointer(d) => &d.nested,
             ImplSource::DiscriminantKind(ImplSourceDiscriminantKindData)
-            | ImplSource::Pointee(ImplSourcePointeeData) => &[],
+            | ImplSource::Pointee(ImplSourcePointeeData)
+            | ImplSource::Tuple => &[],
             ImplSource::TraitAlias(d) => &d.nested,
             ImplSource::TraitUpcasting(d) => &d.nested,
             ImplSource::ConstDestruct(i) => &i.nested,
@@ -750,6 +769,7 @@ impl<'tcx, N> ImplSource<'tcx, N> {
                     nested: i.nested.into_iter().map(f).collect(),
                 })
             }
+            ImplSource::Tuple => ImplSource::Tuple,
         }
     }
 }
@@ -908,6 +928,12 @@ impl ObjectSafetyViolation {
             ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelfOutput, _) => {
                 format!("method `{}` references the `Self` type in its return type", name).into()
             }
+            ObjectSafetyViolation::Method(
+                name,
+                MethodViolationCode::ReferencesImplTraitInTrait,
+                _,
+            ) => format!("method `{}` references an `impl Trait` type in its return type", name)
+                .into(),
             ObjectSafetyViolation::Method(
                 name,
                 MethodViolationCode::WhereClauseReferencesSelf,
@@ -1014,6 +1040,9 @@ pub enum MethodViolationCode {
     /// e.g., `fn foo(&self) -> Self`
     ReferencesSelfOutput,
 
+    /// e.g., `fn foo(&self) -> impl Sized`
+    ReferencesImplTraitInTrait,
+
     /// e.g., `fn foo(&self) where Self: Clone`
     WhereClauseReferencesSelf,
 
@@ -1024,7 +1053,7 @@ pub enum MethodViolationCode {
     UndispatchableReceiver(Option<Span>),
 }
 
-/// These are the error cases for `codegen_fulfill_obligation`.
+/// These are the error cases for `codegen_select_candidate`.
 #[derive(Copy, Clone, Debug, Hash, HashStable, Encodable, Decodable)]
 pub enum CodegenObligationError {
     /// Ambiguity can happen when monomorphizing during trans
diff --git a/compiler/rustc_middle/src/traits/query.rs b/compiler/rustc_middle/src/traits/query.rs
index 1f9b474ade12..fb152b63f634 100644
--- a/compiler/rustc_middle/src/traits/query.rs
+++ b/compiler/rustc_middle/src/traits/query.rs
@@ -5,11 +5,12 @@
 //! The providers for the queries defined here can be found in
 //! `rustc_traits`.
 
+use crate::error::DropCheckOverflow;
 use crate::infer::canonical::{Canonical, QueryResponse};
 use crate::ty::error::TypeError;
-use crate::ty::subst::GenericArg;
+use crate::ty::subst::{GenericArg, SubstsRef};
 use crate::ty::{self, Ty, TyCtxt};
-use rustc_errors::struct_span_err;
+use rustc_hir::def_id::DefId;
 use rustc_span::source_map::Span;
 use std::iter::FromIterator;
 
@@ -117,15 +118,7 @@ pub struct DropckOutlivesResult<'tcx> {
 impl<'tcx> DropckOutlivesResult<'tcx> {
     pub fn report_overflows(&self, tcx: TyCtxt<'tcx>, span: Span, ty: Ty<'tcx>) {
         if let Some(overflow_ty) = self.overflows.get(0) {
-            let mut err = struct_span_err!(
-                tcx.sess,
-                span,
-                E0320,
-                "overflow while adding drop-check rules for {}",
-                ty,
-            );
-            err.note(&format!("overflowed on {}", overflow_ty));
-            err.emit();
+            tcx.sess.emit_err(DropCheckOverflow { span, ty, overflow_ty: *overflow_ty });
         }
     }
 
@@ -227,4 +220,5 @@ pub enum OutlivesBound<'tcx> {
     RegionSubRegion(ty::Region<'tcx>, ty::Region<'tcx>),
     RegionSubParam(ty::Region<'tcx>, ty::ParamTy),
     RegionSubProjection(ty::Region<'tcx>, ty::ProjectionTy<'tcx>),
+    RegionSubOpaque(ty::Region<'tcx>, DefId, SubstsRef<'tcx>),
 }
diff --git a/compiler/rustc_middle/src/traits/select.rs b/compiler/rustc_middle/src/traits/select.rs
index e836ba47eed7..6bcdfd6394a9 100644
--- a/compiler/rustc_middle/src/traits/select.rs
+++ b/compiler/rustc_middle/src/traits/select.rs
@@ -119,8 +119,9 @@ pub enum SelectionCandidate<'tcx> {
 
     /// This is a trait matching with a projected type as `Self`, and we found
     /// an applicable bound in the trait definition. The `usize` is an index
-    /// into the list returned by `tcx.item_bounds`.
-    ProjectionCandidate(usize),
+    /// into the list returned by `tcx.item_bounds`. The constness is the
+    /// constness of the bound in the trait.
+    ProjectionCandidate(usize, ty::BoundConstness),
 
     /// Implementation of a `Fn`-family trait by one of the anonymous types
     /// generated for an `||` expression.
@@ -160,6 +161,9 @@ pub enum SelectionCandidate<'tcx> {
 
     /// Implementation of `const Destruct`, optionally from a custom `impl const Drop`.
     ConstDestructCandidate(Option<DefId>),
+
+    /// Witnesses the fact that a type is a tuple.
+    TupleCandidate,
 }
 
 /// The result of trait evaluation. The order is important
diff --git a/compiler/rustc_middle/src/traits/specialization_graph.rs b/compiler/rustc_middle/src/traits/specialization_graph.rs
index 2465f8e2533e..0a2819feecf0 100644
--- a/compiler/rustc_middle/src/traits/specialization_graph.rs
+++ b/compiler/rustc_middle/src/traits/specialization_graph.rs
@@ -115,7 +115,7 @@ impl Node {
         matches!(self, Node::Trait(..))
     }
 
-    /// Trys to find the associated item that implements `trait_item_def_id`
+    /// Tries to find the associated item that implements `trait_item_def_id`
     /// defined in this node.
     ///
     /// If this returns `None`, the item can potentially still be found in
diff --git a/compiler/rustc_middle/src/traits/structural_impls.rs b/compiler/rustc_middle/src/traits/structural_impls.rs
index 7fbd57ac7354..c526344e1f26 100644
--- a/compiler/rustc_middle/src/traits/structural_impls.rs
+++ b/compiler/rustc_middle/src/traits/structural_impls.rs
@@ -34,6 +34,8 @@ impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSource<'tcx, N> {
             super::ImplSource::TraitUpcasting(ref d) => write!(f, "{:?}", d),
 
             super::ImplSource::ConstDestruct(ref d) => write!(f, "{:?}", d),
+
+            super::ImplSource::Tuple => write!(f, "ImplSource::Tuple"),
         }
     }
 }
diff --git a/compiler/rustc_middle/src/ty/abstract_const.rs b/compiler/rustc_middle/src/ty/abstract_const.rs
index bed809930da6..641e53f2a154 100644
--- a/compiler/rustc_middle/src/ty/abstract_const.rs
+++ b/compiler/rustc_middle/src/ty/abstract_const.rs
@@ -1,7 +1,7 @@
 //! A subset of a mir body used for const evaluatability checking.
 use crate::mir;
 use crate::ty::visit::TypeVisitable;
-use crate::ty::{self, subst::Subst, DelaySpanBugEmitted, EarlyBinder, SubstsRef, Ty, TyCtxt};
+use crate::ty::{self, DelaySpanBugEmitted, EarlyBinder, SubstsRef, Ty, TyCtxt};
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def_id::DefId;
 use std::cmp;
@@ -30,7 +30,7 @@ pub struct AbstractConst<'tcx> {
 impl<'tcx> AbstractConst<'tcx> {
     pub fn new(
         tcx: TyCtxt<'tcx>,
-        uv: ty::Unevaluated<'tcx, ()>,
+        uv: ty::UnevaluatedConst<'tcx>,
     ) -> Result<Option<AbstractConst<'tcx>>, ErrorGuaranteed> {
         let inner = tcx.thir_abstract_const_opt_const_arg(uv.def)?;
         debug!("AbstractConst::new({:?}) = {:?}", uv, inner);
@@ -42,7 +42,7 @@ impl<'tcx> AbstractConst<'tcx> {
         ct: ty::Const<'tcx>,
     ) -> Result<Option<AbstractConst<'tcx>>, ErrorGuaranteed> {
         match ct.kind() {
-            ty::ConstKind::Unevaluated(uv) => AbstractConst::new(tcx, uv.shrink()),
+            ty::ConstKind::Unevaluated(uv) => AbstractConst::new(tcx, uv),
             ty::ConstKind::Error(DelaySpanBugEmitted { reported, .. }) => Err(reported),
             _ => Ok(None),
         }
diff --git a/compiler/rustc_middle/src/ty/adjustment.rs b/compiler/rustc_middle/src/ty/adjustment.rs
index d36cf2fe3f8d..b809f176760d 100644
--- a/compiler/rustc_middle/src/ty/adjustment.rs
+++ b/compiler/rustc_middle/src/ty/adjustment.rs
@@ -77,7 +77,7 @@ pub enum PointerCast {
 ///    At some point, of course, `Box` should move out of the compiler, in which
 ///    case this is analogous to transforming a struct. E.g., `Box<[i32; 4]>` ->
 ///    `Box<[i32]>` is an `Adjust::Unsize` with the target `Box<[i32]>`.
-#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct Adjustment<'tcx> {
     pub kind: Adjust<'tcx>,
     pub target: Ty<'tcx>,
@@ -89,7 +89,7 @@ impl<'tcx> Adjustment<'tcx> {
     }
 }
 
-#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub enum Adjust<'tcx> {
     /// Go from ! to any type.
     NeverToAny,
@@ -108,7 +108,7 @@ pub enum Adjust<'tcx> {
 /// The target type is `U` in both cases, with the region and mutability
 /// being those shared by both the receiver and the returned reference.
 #[derive(Copy, Clone, PartialEq, Debug, TyEncodable, TyDecodable, HashStable)]
-#[derive(TypeFoldable, TypeVisitable)]
+#[derive(TypeFoldable, TypeVisitable, Lift)]
 pub struct OverloadedDeref<'tcx> {
     pub region: ty::Region<'tcx>,
     pub mutbl: hir::Mutability,
@@ -167,7 +167,7 @@ impl From<AutoBorrowMutability> for hir::Mutability {
 }
 
 #[derive(Copy, Clone, PartialEq, Debug, TyEncodable, TyDecodable, HashStable)]
-#[derive(TypeFoldable, TypeVisitable)]
+#[derive(TypeFoldable, TypeVisitable, Lift)]
 pub enum AutoBorrow<'tcx> {
     /// Converts from T to &T.
     Ref(ty::Region<'tcx>, AutoBorrowMutability),
diff --git a/compiler/rustc_middle/src/ty/assoc.rs b/compiler/rustc_middle/src/ty/assoc.rs
index c97156ac17ff..55ee5bd2f810 100644
--- a/compiler/rustc_middle/src/ty/assoc.rs
+++ b/compiler/rustc_middle/src/ty/assoc.rs
@@ -42,7 +42,7 @@ impl AssocItem {
     }
 
     #[inline]
-    pub fn visibility(&self, tcx: TyCtxt<'_>) -> Visibility {
+    pub fn visibility(&self, tcx: TyCtxt<'_>) -> Visibility<DefId> {
         tcx.visibility(self.def_id)
     }
 
diff --git a/compiler/rustc_middle/src/ty/binding.rs b/compiler/rustc_middle/src/ty/binding.rs
index 3d65429f2e53..a5b05a4f9b52 100644
--- a/compiler/rustc_middle/src/ty/binding.rs
+++ b/compiler/rustc_middle/src/ty/binding.rs
@@ -1,6 +1,4 @@
-use rustc_hir::BindingAnnotation;
-use rustc_hir::BindingAnnotation::*;
-use rustc_hir::Mutability;
+use rustc_hir::{BindingAnnotation, ByRef, Mutability};
 
 #[derive(Clone, PartialEq, TyEncodable, TyDecodable, Debug, Copy, HashStable)]
 pub enum BindingMode {
@@ -11,12 +9,10 @@ pub enum BindingMode {
 TrivialTypeTraversalAndLiftImpls! { BindingMode, }
 
 impl BindingMode {
-    pub fn convert(ba: BindingAnnotation) -> BindingMode {
-        match ba {
-            Unannotated => BindingMode::BindByValue(Mutability::Not),
-            Mutable => BindingMode::BindByValue(Mutability::Mut),
-            Ref => BindingMode::BindByReference(Mutability::Not),
-            RefMut => BindingMode::BindByReference(Mutability::Mut),
+    pub fn convert(BindingAnnotation(by_ref, mutbl): BindingAnnotation) -> BindingMode {
+        match by_ref {
+            ByRef::No => BindingMode::BindByValue(mutbl),
+            ByRef::Yes => BindingMode::BindByReference(mutbl),
         }
     }
 }
diff --git a/compiler/rustc_middle/src/ty/cast.rs b/compiler/rustc_middle/src/ty/cast.rs
index c4b743dd4670..981e2d3b6d2d 100644
--- a/compiler/rustc_middle/src/ty/cast.rs
+++ b/compiler/rustc_middle/src/ty/cast.rs
@@ -33,6 +33,8 @@ pub enum CastTy<'tcx> {
     FnPtr,
     /// Raw pointers.
     Ptr(ty::TypeAndMut<'tcx>),
+    /// Casting into a `dyn*` value.
+    DynStar,
 }
 
 /// Cast Kind. See [RFC 401](https://rust-lang.github.io/rfcs/0401-coercions.html)
@@ -50,6 +52,7 @@ pub enum CastKind {
     ArrayPtrCast,
     FnPtrPtrCast,
     FnPtrAddrCast,
+    DynStarCast,
 }
 
 impl<'tcx> CastTy<'tcx> {
@@ -67,6 +70,7 @@ impl<'tcx> CastTy<'tcx> {
             ty::Adt(d, _) if d.is_enum() && d.is_payloadfree() => Some(CastTy::Int(IntTy::CEnum)),
             ty::RawPtr(mt) => Some(CastTy::Ptr(mt)),
             ty::FnPtr(..) => Some(CastTy::FnPtr),
+            ty::Dynamic(_, _, ty::DynStar) => Some(CastTy::DynStar),
             _ => None,
         }
     }
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index f8792edc017b..315e3794f15e 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -1,9 +1,6 @@
 use crate::mir::interpret::LitToConstInput;
 use crate::mir::ConstantKind;
-use crate::ty::{
-    self, InlineConstSubsts, InlineConstSubstsParts, InternalSubsts, ParamEnv, ParamEnvAnd, Ty,
-    TyCtxt, TypeVisitable,
-};
+use crate::ty::{self, InternalSubsts, ParamEnv, ParamEnvAnd, Ty, TyCtxt};
 use rustc_data_structures::intern::Interned;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
@@ -41,7 +38,7 @@ pub struct ConstS<'tcx> {
 }
 
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(ConstS<'_>, 48);
+static_assert_size!(ConstS<'_>, 40);
 
 impl<'tcx> Const<'tcx> {
     #[inline]
@@ -65,8 +62,6 @@ impl<'tcx> Const<'tcx> {
         tcx: TyCtxt<'tcx>,
         def: ty::WithOptConstParam<LocalDefId>,
     ) -> Self {
-        debug!("Const::from_anon_const(def={:?})", def);
-
         let body_id = match tcx.hir().get_by_def_id(def.did) {
             hir::Node::AnonConst(ac) => ac.body,
             _ => span_bug!(
@@ -83,10 +78,9 @@ impl<'tcx> Const<'tcx> {
         match Self::try_eval_lit_or_param(tcx, ty, expr) {
             Some(v) => v,
             None => tcx.mk_const(ty::ConstS {
-                kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
+                kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst {
                     def: def.to_global(),
                     substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
-                    promoted: None,
                 }),
                 ty,
             }),
@@ -153,46 +147,6 @@ impl<'tcx> Const<'tcx> {
         }
     }
 
-    pub fn from_inline_const(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
-        debug!("Const::from_inline_const(def_id={:?})", def_id);
-
-        let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-
-        let body_id = match tcx.hir().get(hir_id) {
-            hir::Node::AnonConst(ac) => ac.body,
-            _ => span_bug!(
-                tcx.def_span(def_id.to_def_id()),
-                "from_inline_const can only process anonymous constants"
-            ),
-        };
-
-        let expr = &tcx.hir().body(body_id).value;
-
-        let ty = tcx.typeck(def_id).node_type(hir_id);
-
-        let ret = match Self::try_eval_lit_or_param(tcx, ty, expr) {
-            Some(v) => v,
-            None => {
-                let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id());
-                let parent_substs =
-                    tcx.erase_regions(InternalSubsts::identity_for_item(tcx, typeck_root_def_id));
-                let substs =
-                    InlineConstSubsts::new(tcx, InlineConstSubstsParts { parent_substs, ty })
-                        .substs;
-                tcx.mk_const(ty::ConstS {
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                        def: ty::WithOptConstParam::unknown(def_id).to_global(),
-                        substs,
-                        promoted: None,
-                    }),
-                    ty,
-                })
-            }
-        };
-        debug_assert!(!ret.has_free_regions());
-        ret
-    }
-
     /// Interns the given value as a constant.
     #[inline]
     pub fn from_value(tcx: TyCtxt<'tcx>, val: ty::ValTree<'tcx>, ty: Ty<'tcx>) -> Self {
diff --git a/compiler/rustc_middle/src/ty/consts/kind.rs b/compiler/rustc_middle/src/ty/consts/kind.rs
index cb0137d2e5e0..c444ec23563c 100644
--- a/compiler/rustc_middle/src/ty/consts/kind.rs
+++ b/compiler/rustc_middle/src/ty/consts/kind.rs
@@ -1,7 +1,7 @@
 use std::convert::TryInto;
 
+use crate::mir;
 use crate::mir::interpret::{AllocId, ConstValue, Scalar};
-use crate::mir::Promoted;
 use crate::ty::subst::{InternalSubsts, SubstsRef};
 use crate::ty::ParamEnv;
 use crate::ty::{self, TyCtxt, TypeVisitable};
@@ -11,40 +11,41 @@ use rustc_macros::HashStable;
 use rustc_target::abi::Size;
 
 use super::ScalarInt;
-/// An unevaluated, potentially generic, constant.
+
+/// An unevaluated (potentially generic) constant used in the type-system.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Lift)]
 #[derive(Hash, HashStable)]
-pub struct Unevaluated<'tcx, P = Option<Promoted>> {
+pub struct UnevaluatedConst<'tcx> {
     pub def: ty::WithOptConstParam<DefId>,
     pub substs: SubstsRef<'tcx>,
-    pub promoted: P,
 }
 
-impl<'tcx> Unevaluated<'tcx> {
-    #[inline]
-    pub fn shrink(self) -> Unevaluated<'tcx, ()> {
-        debug_assert_eq!(self.promoted, None);
-        Unevaluated { def: self.def, substs: self.substs, promoted: () }
+impl rustc_errors::IntoDiagnosticArg for UnevaluatedConst<'_> {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        format!("{:?}", self).into_diagnostic_arg()
     }
 }
 
-impl<'tcx> Unevaluated<'tcx, ()> {
+impl<'tcx> UnevaluatedConst<'tcx> {
     #[inline]
-    pub fn expand(self) -> Unevaluated<'tcx> {
-        Unevaluated { def: self.def, substs: self.substs, promoted: None }
+    pub fn expand(self) -> mir::UnevaluatedConst<'tcx> {
+        mir::UnevaluatedConst { def: self.def, substs: self.substs, promoted: None }
     }
 }
 
-impl<'tcx, P: Default> Unevaluated<'tcx, P> {
+impl<'tcx> UnevaluatedConst<'tcx> {
     #[inline]
-    pub fn new(def: ty::WithOptConstParam<DefId>, substs: SubstsRef<'tcx>) -> Unevaluated<'tcx, P> {
-        Unevaluated { def, substs, promoted: Default::default() }
+    pub fn new(
+        def: ty::WithOptConstParam<DefId>,
+        substs: SubstsRef<'tcx>,
+    ) -> UnevaluatedConst<'tcx> {
+        UnevaluatedConst { def, substs }
     }
 }
 
 /// Represents a constant in Rust.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
-#[derive(Hash, HashStable)]
+#[derive(Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum ConstKind<'tcx> {
     /// A const generic parameter.
     Param(ty::ParamConst),
@@ -60,7 +61,7 @@ pub enum ConstKind<'tcx> {
 
     /// Used in the HIR by using `Unevaluated` everywhere and later normalizing to one of the other
     /// variants when the code is monomorphic enough for that.
-    Unevaluated(Unevaluated<'tcx>),
+    Unevaluated(UnevaluatedConst<'tcx>),
 
     /// Used to hold computed value.
     Value(ty::ValTree<'tcx>),
@@ -71,7 +72,7 @@ pub enum ConstKind<'tcx> {
 }
 
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(ConstKind<'_>, 40);
+static_assert_size!(ConstKind<'_>, 32);
 
 impl<'tcx> ConstKind<'tcx> {
     #[inline]
@@ -174,6 +175,7 @@ impl<'tcx> ConstKind<'tcx> {
         param_env: ParamEnv<'tcx>,
         eval_mode: EvalMode,
     ) -> Option<Result<EvalResult<'tcx>, ErrorGuaranteed>> {
+        assert!(!self.has_escaping_bound_vars(), "escaping vars in {self:?}");
         if let ConstKind::Unevaluated(unevaluated) = self {
             use crate::mir::interpret::ErrorHandled;
 
@@ -194,10 +196,9 @@ impl<'tcx> ConstKind<'tcx> {
             // FIXME(eddyb, skinny121) pass `InferCtxt` into here when it's available, so that
             // we can call `infcx.const_eval_resolve` which handles inference variables.
             let param_env_and = if param_env_and.needs_infer() {
-                tcx.param_env(unevaluated.def.did).and(ty::Unevaluated {
+                tcx.param_env(unevaluated.def.did).and(ty::UnevaluatedConst {
                     def: unevaluated.def,
                     substs: InternalSubsts::identity_for_item(tcx, unevaluated.def.did),
-                    promoted: unevaluated.promoted,
                 })
             } else {
                 param_env_and
@@ -221,7 +222,7 @@ impl<'tcx> ConstKind<'tcx> {
                     }
                 }
                 EvalMode::Mir => {
-                    match tcx.const_eval_resolve(param_env, unevaluated, None) {
+                    match tcx.const_eval_resolve(param_env, unevaluated.expand(), None) {
                         // NOTE(eddyb) `val` contains no lifetimes/types/consts,
                         // and we use the original type, so nothing from `substs`
                         // (which may be identity substs, see above),
diff --git a/compiler/rustc_middle/src/ty/consts/valtree.rs b/compiler/rustc_middle/src/ty/consts/valtree.rs
index 93707bb18cee..a803fca0d5b8 100644
--- a/compiler/rustc_middle/src/ty/consts/valtree.rs
+++ b/compiler/rustc_middle/src/ty/consts/valtree.rs
@@ -18,7 +18,7 @@ use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 /// `ValTree` does not have this problem with representation, as it only contains integers or
 /// lists of (nested) `ValTree`.
 pub enum ValTree<'tcx> {
-    /// ZSTs, integers, `bool`, `char` are represented as scalars.
+    /// integers, `bool`, `char` are represented as scalars.
     /// See the `ScalarInt` documentation for how `ScalarInt` guarantees that equal values
     /// of these types have the same representation.
     Leaf(ScalarInt),
@@ -27,8 +27,11 @@ pub enum ValTree<'tcx> {
     // dont use SliceOrStr for now
     /// The fields of any kind of aggregate. Structs, tuples and arrays are represented by
     /// listing their fields' values in order.
+    ///
     /// Enums are represented by storing their discriminant as a field, followed by all
     /// the fields of the variant.
+    ///
+    /// ZST types are represented as an empty slice.
     Branch(&'tcx [ValTree<'tcx>]),
 }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 0f34aa10a125..e430c327efe7 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1,7 +1,7 @@
 //! Type context book-keeping.
 
 use crate::arena::Arena;
-use crate::dep_graph::{DepGraph, DepKind, DepKindStruct};
+use crate::dep_graph::{DepGraph, DepKindStruct};
 use crate::hir::place::Place as HirPlace;
 use crate::infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
 use crate::lint::{struct_lint_level, LintLevelSource};
@@ -15,14 +15,15 @@ use crate::mir::{
 use crate::thir::Thir;
 use crate::traits;
 use crate::ty::query::{self, TyCtxtAt};
-use crate::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef, UserSubsts};
 use crate::ty::{
     self, AdtDef, AdtDefData, AdtKind, Binder, BindingMode, BoundVar, CanonicalPolyFnSig,
     ClosureSizeProfileData, Const, ConstS, ConstVid, DefIdTree, ExistentialPredicate, FloatTy,
     FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy, IntTy, IntVar, IntVid, List,
     ParamConst, ParamTy, PolyFnSig, Predicate, PredicateKind, PredicateS, ProjectionTy, Region,
     RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar, TyVid, TypeAndMut, UintTy,
+    Visibility,
 };
+use crate::ty::{GenericArg, GenericArgKind, InternalSubsts, SubstsRef, UserSubsts};
 use rustc_ast as ast;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -39,6 +40,7 @@ use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LOCAL_CRATE};
 use rustc_hir::definitions::Definitions;
+use rustc_hir::hir_id::OwnerId;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{
@@ -52,6 +54,7 @@ use rustc_query_system::ich::StableHashingContext;
 use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
 use rustc_session::config::{CrateType, OutputFilenames};
 use rustc_session::cstore::CrateStoreDyn;
+use rustc_session::errors::TargetDataLayoutErrorsWrapper;
 use rustc_session::lint::{Level, Lint};
 use rustc_session::Limit;
 use rustc_session::Session;
@@ -62,7 +65,7 @@ use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::{Layout, LayoutS, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
 use rustc_type_ir::sty::TyKind::*;
-use rustc_type_ir::{InternAs, InternIteratorElement, Interner, TypeFlags};
+use rustc_type_ir::{DynKind, InternAs, InternIteratorElement, Interner, TypeFlags};
 
 use std::any::Any;
 use std::borrow::Borrow;
@@ -275,9 +278,6 @@ pub struct CommonTypes<'tcx> {
 }
 
 pub struct CommonLifetimes<'tcx> {
-    /// `ReEmpty` in the root universe.
-    pub re_root_empty: Region<'tcx>,
-
     /// `ReStatic`
     pub re_static: Region<'tcx>,
 
@@ -290,7 +290,7 @@ pub struct CommonConsts<'tcx> {
 }
 
 pub struct LocalTableInContext<'a, V> {
-    hir_owner: LocalDefId,
+    hir_owner: OwnerId,
     data: &'a ItemLocalMap<V>,
 }
 
@@ -302,7 +302,7 @@ pub struct LocalTableInContext<'a, V> {
 /// would result in lookup errors, or worse, in silently wrong data being
 /// stored/returned.
 #[inline]
-fn validate_hir_id_for_typeck_results(hir_owner: LocalDefId, hir_id: hir::HirId) {
+fn validate_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
     if hir_id.owner != hir_owner {
         invalid_hir_id_for_typeck_results(hir_owner, hir_id);
     }
@@ -310,7 +310,7 @@ fn validate_hir_id_for_typeck_results(hir_owner: LocalDefId, hir_id: hir::HirId)
 
 #[cold]
 #[inline(never)]
-fn invalid_hir_id_for_typeck_results(hir_owner: LocalDefId, hir_id: hir::HirId) {
+fn invalid_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
     ty::tls::with(|tcx| {
         bug!(
             "node {} with HirId::owner {:?} cannot be placed in TypeckResults with hir_owner {:?}",
@@ -346,7 +346,7 @@ impl<'a, V> ::std::ops::Index<hir::HirId> for LocalTableInContext<'a, V> {
 }
 
 pub struct LocalTableInContextMut<'a, V> {
-    hir_owner: LocalDefId,
+    hir_owner: OwnerId,
     data: &'a mut ItemLocalMap<V>,
 }
 
@@ -418,7 +418,7 @@ pub struct GeneratorDiagnosticData<'tcx> {
 #[derive(TyEncodable, TyDecodable, Debug, HashStable)]
 pub struct TypeckResults<'tcx> {
     /// The `HirId::owner` all `ItemLocalId`s in this table are relative to.
-    pub hir_owner: LocalDefId,
+    pub hir_owner: OwnerId,
 
     /// Resolved definitions for `<T>::X` associated paths and
     /// method calls, including those of overloaded operators.
@@ -593,7 +593,7 @@ pub struct TypeckResults<'tcx> {
 }
 
 impl<'tcx> TypeckResults<'tcx> {
-    pub fn new(hir_owner: LocalDefId) -> TypeckResults<'tcx> {
+    pub fn new(hir_owner: OwnerId) -> TypeckResults<'tcx> {
         TypeckResults {
             hir_owner,
             type_dependent_defs: Default::default(),
@@ -874,7 +874,7 @@ pub type CanonicalUserTypeAnnotations<'tcx> =
 
 #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct CanonicalUserTypeAnnotation<'tcx> {
-    pub user_ty: CanonicalUserType<'tcx>,
+    pub user_ty: Box<CanonicalUserType<'tcx>>,
     pub span: Span,
     pub inferred_ty: Ty<'tcx>,
 }
@@ -986,11 +986,7 @@ impl<'tcx> CommonLifetimes<'tcx> {
             ))
         };
 
-        CommonLifetimes {
-            re_root_empty: mk(ty::ReEmpty(ty::UniverseIndex::ROOT)),
-            re_static: mk(ty::ReStatic),
-            re_erased: mk(ty::ReErased),
-        }
+        CommonLifetimes { re_static: mk(ty::ReStatic), re_erased: mk(ty::ReErased) }
     }
 }
 
@@ -1089,7 +1085,7 @@ pub struct GlobalCtxt<'tcx> {
 
     pub queries: &'tcx dyn query::QueryEngine<'tcx>,
     pub query_caches: query::QueryCaches<'tcx>,
-    query_kinds: &'tcx [DepKindStruct],
+    pub(crate) query_kinds: &'tcx [DepKindStruct<'tcx>],
 
     // Internal caches for metadata decoding. No need to track deps on this.
     pub ty_rcache: Lock<FxHashMap<ty::CReaderCacheKey, Ty<'tcx>>>,
@@ -1246,12 +1242,12 @@ impl<'tcx> TyCtxt<'tcx> {
         dep_graph: DepGraph,
         on_disk_cache: Option<&'tcx dyn OnDiskCache<'tcx>>,
         queries: &'tcx dyn query::QueryEngine<'tcx>,
-        query_kinds: &'tcx [DepKindStruct],
+        query_kinds: &'tcx [DepKindStruct<'tcx>],
         crate_name: &str,
         output_filenames: OutputFilenames,
     ) -> GlobalCtxt<'tcx> {
         let data_layout = TargetDataLayout::parse(&s.target).unwrap_or_else(|err| {
-            s.fatal(&err);
+            s.emit_fatal(TargetDataLayoutErrorsWrapper(err));
         });
         let interners = CtxtInterners::new(arena);
         let common_types = CommonTypes::new(
@@ -1296,10 +1292,6 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    pub(crate) fn query_kind(self, k: DepKind) -> &'tcx DepKindStruct {
-        &self.query_kinds[k as usize]
-    }
-
     /// Constructs a `TyKind::Error` type and registers a `delay_span_bug` to ensure it gets used.
     #[track_caller]
     pub fn ty_error(self) -> Ty<'tcx> {
@@ -1498,17 +1490,17 @@ impl<'tcx> TyCtxt<'tcx> {
         // Create a dependency to the crate to be sure we re-execute this when the amount of
         // definitions change.
         self.ensure().hir_crate(());
-        // Leak a read lock once we start iterating on definitions, to prevent adding new onces
+        // Leak a read lock once we start iterating on definitions, to prevent adding new ones
         // while iterating.  If some query needs to add definitions, it should be `ensure`d above.
         let definitions = self.definitions.leak();
         definitions.iter_local_def_id()
     }
 
     pub fn def_path_table(self) -> &'tcx rustc_hir::definitions::DefPathTable {
-        // Create a dependency to the crate to be sure we reexcute this when the amount of
+        // Create a dependency to the crate to be sure we re-execute this when the amount of
         // definitions change.
         self.ensure().hir_crate(());
-        // Leak a read lock once we start iterating on definitions, to prevent adding new onces
+        // Leak a read lock once we start iterating on definitions, to prevent adding new ones
         // while iterating.  If some query needs to add definitions, it should be `ensure`d above.
         let definitions = self.definitions.leak();
         definitions.def_path_table()
@@ -1517,10 +1509,10 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn def_path_hash_to_def_index_map(
         self,
     ) -> &'tcx rustc_hir::def_path_hash_map::DefPathHashMap {
-        // Create a dependency to the crate to be sure we reexcute this when the amount of
+        // Create a dependency to the crate to be sure we re-execute this when the amount of
         // definitions change.
         self.ensure().hir_crate(());
-        // Leak a read lock once we start iterating on definitions, to prevent adding new onces
+        // Leak a read lock once we start iterating on definitions, to prevent adding new ones
         // while iterating.  If some query needs to add definitions, it should be `ensure`d above.
         let definitions = self.definitions.leak();
         definitions.def_path_hash_to_def_index_map()
@@ -1596,7 +1588,7 @@ impl<'tcx> TyCtxt<'tcx> {
         })
     }
 
-    // Returns the `DefId` and the `BoundRegionKind` corresponding to the given region.
+    /// Returns the `DefId` and the `BoundRegionKind` corresponding to the given region.
     pub fn is_suitable_region(self, region: Region<'tcx>) -> Option<FreeRegionInfo> {
         let (suitable_region_binding_scope, bound_region) = match *region {
             ty::ReFree(ref free_region) => {
@@ -1728,6 +1720,11 @@ impl<'tcx> TyCtxt<'tcx> {
             .chain(self.crates(()).iter().copied())
             .flat_map(move |cnum| self.traits_in_crate(cnum).iter().copied())
     }
+
+    #[inline]
+    pub fn local_visibility(self, def_id: LocalDefId) -> Visibility {
+        self.visibility(def_id).expect_local()
+    }
 }
 
 /// A trait implemented for all `X<'a>` types that can be safely and
@@ -1821,7 +1818,9 @@ nop_list_lift! {bound_variable_kinds; ty::BoundVariableKind => ty::BoundVariable
 // This is the impl for `&'a InternalSubsts<'a>`.
 nop_list_lift! {substs; GenericArg<'a> => GenericArg<'tcx>}
 
-CloneLiftImpls! { for<'tcx> { Constness, traits::WellFormedLoc, } }
+CloneLiftImpls! { for<'tcx> {
+    Constness, traits::WellFormedLoc, ImplPolarity, crate::mir::ReturnConstraint,
+} }
 
 pub mod tls {
     use super::{ptr_eq, GlobalCtxt, TyCtxt};
@@ -1829,9 +1828,9 @@ pub mod tls {
     use crate::dep_graph::TaskDepsRef;
     use crate::ty::query;
     use rustc_data_structures::sync::{self, Lock};
-    use rustc_data_structures::thin_vec::ThinVec;
     use rustc_errors::Diagnostic;
     use std::mem;
+    use thin_vec::ThinVec;
 
     #[cfg(not(parallel_compiler))]
     use std::cell::Cell;
@@ -2546,8 +2545,9 @@ impl<'tcx> TyCtxt<'tcx> {
         self,
         obj: &'tcx List<ty::Binder<'tcx, ExistentialPredicate<'tcx>>>,
         reg: ty::Region<'tcx>,
+        repr: DynKind,
     ) -> Ty<'tcx> {
-        self.mk_ty(Dynamic(obj, reg))
+        self.mk_ty(Dynamic(obj, reg, repr))
     }
 
     #[inline]
@@ -2904,7 +2904,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn is_late_bound(self, id: HirId) -> bool {
-        self.is_late_bound_map(id.owner).map_or(false, |set| {
+        self.is_late_bound_map(id.owner.def_id).map_or(false, |set| {
             let def_id = self.hir().local_def_id(id);
             set.contains(&def_id)
         })
diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs
index dd2f43210603..855917fb8286 100644
--- a/compiler/rustc_middle/src/ty/diagnostics.rs
+++ b/compiler/rustc_middle/src/ty/diagnostics.rs
@@ -102,13 +102,25 @@ pub fn suggest_arbitrary_trait_bound<'tcx>(
     generics: &hir::Generics<'_>,
     err: &mut Diagnostic,
     trait_pred: PolyTraitPredicate<'tcx>,
+    associated_ty: Option<(&'static str, Ty<'tcx>)>,
 ) -> bool {
     if !trait_pred.is_suggestable(tcx, false) {
         return false;
     }
 
     let param_name = trait_pred.skip_binder().self_ty().to_string();
-    let constraint = trait_pred.print_modifiers_and_trait_path().to_string();
+    let mut constraint = trait_pred.print_modifiers_and_trait_path().to_string();
+
+    if let Some((name, term)) = associated_ty {
+        // FIXME: this case overlaps with code in TyCtxt::note_and_explain_type_err.
+        // That should be extracted into a helper function.
+        if constraint.ends_with('>') {
+            constraint = format!("{}, {} = {}>", &constraint[..constraint.len() - 1], name, term);
+        } else {
+            constraint.push_str(&format!("<{} = {}>", name, term));
+        }
+    }
+
     let param = generics.params.iter().find(|p| p.name.ident().as_str() == param_name);
 
     // Skip, there is a param named Self
@@ -396,7 +408,7 @@ impl<'v> hir::intravisit::Visitor<'v> for TraitObjectVisitor<'v> {
             ) => {
                 self.0.push(ty);
             }
-            hir::TyKind::OpaqueDef(item_id, _) => {
+            hir::TyKind::OpaqueDef(item_id, _, _) => {
                 self.0.push(ty);
                 let item = self.1.item(item_id);
                 hir::intravisit::walk_item(self, item);
@@ -455,7 +467,7 @@ impl<'tcx> TypeVisitor<'tcx> for IsSuggestableVisitor<'tcx> {
                 }
             }
 
-            Dynamic(dty, _) => {
+            Dynamic(dty, _, _) => {
                 for pred in *dty {
                     match pred.skip_binder() {
                         ExistentialPredicate::Trait(_) | ExistentialPredicate::Projection(_) => {
diff --git a/compiler/rustc_middle/src/ty/error.rs b/compiler/rustc_middle/src/ty/error.rs
index da564c66a70e..52f16ad88f69 100644
--- a/compiler/rustc_middle/src/ty/error.rs
+++ b/compiler/rustc_middle/src/ty/error.rs
@@ -2,6 +2,7 @@ use crate::traits::{ObligationCause, ObligationCauseCode};
 use crate::ty::diagnostics::suggest_constraining_type_param;
 use crate::ty::print::{FmtPrinter, Printer};
 use crate::ty::{self, BoundRegionKind, Region, Ty, TyCtxt};
+use hir::def::DefKind;
 use rustc_errors::Applicability::{MachineApplicable, MaybeIncorrect};
 use rustc_errors::{pluralize, Diagnostic, MultiSpan};
 use rustc_hir as hir;
@@ -13,7 +14,7 @@ use rustc_target::spec::abi;
 use std::borrow::Cow;
 use std::fmt;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable, Lift)]
 pub struct ExpectedFound<T> {
     pub expected: T,
     pub found: T,
@@ -30,7 +31,7 @@ impl<T> ExpectedFound<T> {
 }
 
 // Data structures used in type unification
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
 #[rustc_pass_by_value]
 pub enum TypeError<'tcx> {
     Mismatch,
@@ -538,7 +539,7 @@ impl<T> Trait<T> for X {
                             diag.span_label(p_span, "this type parameter");
                         }
                     }
-                    (ty::Projection(proj_ty), _) => {
+                    (ty::Projection(proj_ty), _) if self.def_kind(proj_ty.item_def_id) != DefKind::ImplTraitPlaceholder => {
                         self.expected_projection(
                             diag,
                             proj_ty,
@@ -547,7 +548,7 @@ impl<T> Trait<T> for X {
                             cause.code(),
                         );
                     }
-                    (_, ty::Projection(proj_ty)) => {
+                    (_, ty::Projection(proj_ty)) if self.def_kind(proj_ty.item_def_id) != DefKind::ImplTraitPlaceholder => {
                         let msg = format!(
                             "consider constraining the associated type `{}` to `{}`",
                             values.found, values.expected,
@@ -860,7 +861,7 @@ fn foo(&self) -> Self::T { String::new() }
         // When `body_owner` is an `impl` or `trait` item, look in its associated types for
         // `expected` and point at it.
         let parent_id = self.hir().get_parent_item(hir_id);
-        let item = self.hir().find_by_def_id(parent_id);
+        let item = self.hir().find_by_def_id(parent_id.def_id);
         debug!("expected_projection parent item {:?}", item);
         match item {
             Some(hir::Node::Item(hir::Item { kind: hir::ItemKind::Trait(.., items), .. })) => {
diff --git a/compiler/rustc_middle/src/ty/fast_reject.rs b/compiler/rustc_middle/src/ty/fast_reject.rs
index 8d019a3bad8c..41bb3c714017 100644
--- a/compiler/rustc_middle/src/ty/fast_reject.rs
+++ b/compiler/rustc_middle/src/ty/fast_reject.rs
@@ -384,14 +384,7 @@ impl DeepRejectCtxt {
             // they might unify with any value.
             ty::ConstKind::Unevaluated(_) | ty::ConstKind::Error(_) => true,
             ty::ConstKind::Value(obl) => match k {
-                ty::ConstKind::Value(imp) => {
-                    // FIXME(valtrees): Once we have valtrees, we can just
-                    // compare them directly here.
-                    match (obl.try_to_scalar_int(), imp.try_to_scalar_int()) {
-                        (Some(obl), Some(imp)) => obl == imp,
-                        _ => true,
-                    }
-                }
+                ty::ConstKind::Value(imp) => obl == imp,
                 _ => true,
             },
 
diff --git a/compiler/rustc_middle/src/ty/flags.rs b/compiler/rustc_middle/src/ty/flags.rs
index ea6bb8a7abd4..a6d0678e99d6 100644
--- a/compiler/rustc_middle/src/ty/flags.rs
+++ b/compiler/rustc_middle/src/ty/flags.rs
@@ -1,5 +1,5 @@
 use crate::ty::subst::{GenericArg, GenericArgKind};
-use crate::ty::{self, InferConst, Term, Ty, TypeFlags};
+use crate::ty::{self, InferConst, Ty, TypeFlags};
 use std::slice;
 
 #[derive(Debug)]
@@ -34,7 +34,7 @@ impl FlagComputation {
         result.flags
     }
 
-    pub fn for_unevaluated_const(uv: ty::Unevaluated<'_>) -> TypeFlags {
+    pub fn for_unevaluated_const(uv: ty::UnevaluatedConst<'_>) -> TypeFlags {
         let mut result = FlagComputation::new();
         result.add_unevaluated_const(uv);
         result.flags
@@ -171,7 +171,7 @@ impl FlagComputation {
                 self.add_substs(substs);
             }
 
-            &ty::Dynamic(obj, r) => {
+            &ty::Dynamic(obj, r, _) => {
                 for predicate in obj.iter() {
                     self.bound_computation(predicate, |computation, predicate| match predicate {
                         ty::ExistentialPredicate::Trait(tr) => computation.add_substs(tr.substs),
@@ -243,9 +243,9 @@ impl FlagComputation {
             }
             ty::PredicateKind::Projection(ty::ProjectionPredicate { projection_ty, term }) => {
                 self.add_projection_ty(projection_ty);
-                match term {
-                    Term::Ty(ty) => self.add_ty(ty),
-                    Term::Const(c) => self.add_const(c),
+                match term.unpack() {
+                    ty::TermKind::Ty(ty) => self.add_ty(ty),
+                    ty::TermKind::Const(c) => self.add_const(c),
                 }
             }
             ty::PredicateKind::WellFormed(arg) => {
@@ -313,16 +313,16 @@ impl FlagComputation {
         }
     }
 
-    fn add_unevaluated_const<P>(&mut self, ct: ty::Unevaluated<'_, P>) {
+    fn add_unevaluated_const(&mut self, ct: ty::UnevaluatedConst<'_>) {
         self.add_substs(ct.substs);
         self.add_flags(TypeFlags::HAS_CT_PROJECTION);
     }
 
     fn add_existential_projection(&mut self, projection: &ty::ExistentialProjection<'_>) {
         self.add_substs(projection.substs);
-        match projection.term {
-            ty::Term::Ty(ty) => self.add_ty(ty),
-            ty::Term::Const(ct) => self.add_const(ct),
+        match projection.term.unpack() {
+            ty::TermKind::Ty(ty) => self.add_ty(ty),
+            ty::TermKind::Const(ct) => self.add_const(ct),
         }
     }
 
diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index 5e96e278b9ca..e4234442faef 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -128,7 +128,17 @@ pub trait TypeFolder<'tcx>: FallibleTypeFolder<'tcx, Error = !> {
         c.super_fold_with(self)
     }
 
-    fn fold_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ty::Unevaluated<'tcx> {
+    fn fold_ty_unevaluated(
+        &mut self,
+        uv: ty::UnevaluatedConst<'tcx>,
+    ) -> ty::UnevaluatedConst<'tcx> {
+        uv.super_fold_with(self)
+    }
+
+    fn fold_mir_unevaluated(
+        &mut self,
+        uv: mir::UnevaluatedConst<'tcx>,
+    ) -> mir::UnevaluatedConst<'tcx> {
         uv.super_fold_with(self)
     }
 
@@ -172,10 +182,17 @@ pub trait FallibleTypeFolder<'tcx>: Sized {
         c.try_super_fold_with(self)
     }
 
-    fn try_fold_unevaluated(
+    fn try_fold_ty_unevaluated(
         &mut self,
-        c: ty::Unevaluated<'tcx>,
-    ) -> Result<ty::Unevaluated<'tcx>, Self::Error> {
+        c: ty::UnevaluatedConst<'tcx>,
+    ) -> Result<ty::UnevaluatedConst<'tcx>, Self::Error> {
+        c.try_super_fold_with(self)
+    }
+
+    fn try_fold_mir_unevaluated(
+        &mut self,
+        c: mir::UnevaluatedConst<'tcx>,
+    ) -> Result<mir::UnevaluatedConst<'tcx>, Self::Error> {
         c.try_super_fold_with(self)
     }
 
@@ -225,11 +242,18 @@ where
         Ok(self.fold_const(c))
     }
 
-    fn try_fold_unevaluated(
+    fn try_fold_ty_unevaluated(
         &mut self,
-        c: ty::Unevaluated<'tcx>,
-    ) -> Result<ty::Unevaluated<'tcx>, !> {
-        Ok(self.fold_unevaluated(c))
+        c: ty::UnevaluatedConst<'tcx>,
+    ) -> Result<ty::UnevaluatedConst<'tcx>, !> {
+        Ok(self.fold_ty_unevaluated(c))
+    }
+
+    fn try_fold_mir_unevaluated(
+        &mut self,
+        c: mir::UnevaluatedConst<'tcx>,
+    ) -> Result<mir::UnevaluatedConst<'tcx>, !> {
+        Ok(self.fold_mir_unevaluated(c))
     }
 
     fn try_fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> Result<ty::Predicate<'tcx>, !> {
@@ -302,6 +326,17 @@ impl<'tcx> TyCtxt<'tcx> {
     {
         value.fold_with(&mut RegionFolder::new(self, &mut f))
     }
+
+    pub fn super_fold_regions<T>(
+        self,
+        value: T,
+        mut f: impl FnMut(ty::Region<'tcx>, ty::DebruijnIndex) -> ty::Region<'tcx>,
+    ) -> T
+    where
+        T: TypeSuperFoldable<'tcx>,
+    {
+        value.super_fold_with(&mut RegionFolder::new(self, &mut f))
+    }
 }
 
 /// Folds over the substructure of a type, visiting its component
@@ -353,7 +388,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for RegionFolder<'a, 'tcx> {
         t
     }
 
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "debug", ret)]
     fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
         match *r {
             ty::ReLateBound(debruijn, _) if debruijn < self.current_index => {
@@ -377,17 +412,13 @@ pub trait BoundVarReplacerDelegate<'tcx> {
     fn replace_const(&mut self, bv: ty::BoundVar, ty: Ty<'tcx>) -> ty::Const<'tcx>;
 }
 
-pub struct FnMutDelegate<R, T, C> {
-    pub regions: R,
-    pub types: T,
-    pub consts: C,
+pub struct FnMutDelegate<'a, 'tcx> {
+    pub regions: &'a mut (dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx> + 'a),
+    pub types: &'a mut (dyn FnMut(ty::BoundTy) -> Ty<'tcx> + 'a),
+    pub consts: &'a mut (dyn FnMut(ty::BoundVar, Ty<'tcx>) -> ty::Const<'tcx> + 'a),
 }
-impl<'tcx, R, T, C> BoundVarReplacerDelegate<'tcx> for FnMutDelegate<R, T, C>
-where
-    R: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
-    T: FnMut(ty::BoundTy) -> Ty<'tcx>,
-    C: FnMut(ty::BoundVar, Ty<'tcx>) -> ty::Const<'tcx>,
-{
+
+impl<'a, 'tcx> BoundVarReplacerDelegate<'tcx> for FnMutDelegate<'a, 'tcx> {
     fn replace_region(&mut self, br: ty::BoundRegion) -> ty::Region<'tcx> {
         (self.regions)(br)
     }
@@ -511,7 +542,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn replace_late_bound_regions_uncached<T, F>(
         self,
         value: Binder<'tcx, T>,
-        replace_regions: F,
+        mut replace_regions: F,
     ) -> T
     where
         F: FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
@@ -522,9 +553,9 @@ impl<'tcx> TyCtxt<'tcx> {
             value
         } else {
             let delegate = FnMutDelegate {
-                regions: replace_regions,
-                types: |b| bug!("unexpected bound ty in binder: {b:?}"),
-                consts: |b, ty| bug!("unexpected bound ct in binder: {b:?} {ty}"),
+                regions: &mut replace_regions,
+                types: &mut |b| bug!("unexpected bound ty in binder: {b:?}"),
+                consts: &mut |b, ty| bug!("unexpected bound ct in binder: {b:?} {ty}"),
             };
             let mut replacer = BoundVarReplacer::new(self, delegate);
             value.fold_with(&mut replacer)
@@ -584,19 +615,19 @@ impl<'tcx> TyCtxt<'tcx> {
         self.replace_escaping_bound_vars_uncached(
             value,
             FnMutDelegate {
-                regions: |r: ty::BoundRegion| {
+                regions: &mut |r: ty::BoundRegion| {
                     self.mk_region(ty::ReLateBound(
                         ty::INNERMOST,
                         ty::BoundRegion { var: shift_bv(r.var), kind: r.kind },
                     ))
                 },
-                types: |t: ty::BoundTy| {
+                types: &mut |t: ty::BoundTy| {
                     self.mk_ty(ty::Bound(
                         ty::INNERMOST,
                         ty::BoundTy { var: shift_bv(t.var), kind: t.kind },
                     ))
                 },
-                consts: |c, ty: Ty<'tcx>| {
+                consts: &mut |c, ty: Ty<'tcx>| {
                     self.mk_const(ty::ConstS {
                         kind: ty::ConstKind::Bound(ty::INNERMOST, shift_bv(c)),
                         ty,
diff --git a/compiler/rustc_middle/src/ty/generics.rs b/compiler/rustc_middle/src/ty/generics.rs
index 42b5d5a6efd7..19754d1453f8 100644
--- a/compiler/rustc_middle/src/ty/generics.rs
+++ b/compiler/rustc_middle/src/ty/generics.rs
@@ -1,6 +1,5 @@
 use crate::ty;
-use crate::ty::subst::{Subst, SubstsRef};
-use crate::ty::EarlyBinder;
+use crate::ty::{EarlyBinder, SubstsRef};
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::DefId;
@@ -27,8 +26,9 @@ impl GenericParamDefKind {
     pub fn to_ord(&self) -> ast::ParamKindOrd {
         match self {
             GenericParamDefKind::Lifetime => ast::ParamKindOrd::Lifetime,
-            GenericParamDefKind::Type { .. } => ast::ParamKindOrd::Type,
-            GenericParamDefKind::Const { .. } => ast::ParamKindOrd::Const,
+            GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
+                ast::ParamKindOrd::TypeOrConst
+            }
         }
     }
 
@@ -266,7 +266,7 @@ impl<'tcx> Generics {
         // Filter the default arguments.
         //
         // This currently uses structural equality instead
-        // of semantic equivalance. While not ideal, that's
+        // of semantic equivalence. While not ideal, that's
         // good enough for now as this should only be used
         // for diagnostics anyways.
         own_params.end -= self
@@ -328,6 +328,7 @@ impl<'tcx> GenericPredicates<'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self, tcx))]
     fn instantiate_into(
         &self,
         tcx: TyCtxt<'tcx>,
diff --git a/compiler/rustc_middle/src/ty/instance.rs b/compiler/rustc_middle/src/ty/instance.rs
index 53218225d53b..6c1414f7b8ac 100644
--- a/compiler/rustc_middle/src/ty/instance.rs
+++ b/compiler/rustc_middle/src/ty/instance.rs
@@ -1,9 +1,7 @@
 use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use crate::ty::print::{FmtPrinter, Printer};
-use crate::ty::subst::{InternalSubsts, Subst};
-use crate::ty::{
-    self, EarlyBinder, SubstsRef, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitable,
-};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitable};
+use crate::ty::{EarlyBinder, InternalSubsts, SubstsRef};
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::Namespace;
 use rustc_hir::def_id::{CrateNum, DefId};
@@ -20,14 +18,14 @@ use std::fmt;
 /// simply couples a potentially generic `InstanceDef` with some substs, and codegen and const eval
 /// will do all required substitution as they run.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
-#[derive(HashStable, Lift)]
+#[derive(HashStable, Lift, TypeFoldable, TypeVisitable)]
 pub struct Instance<'tcx> {
     pub def: InstanceDef<'tcx>,
     pub substs: SubstsRef<'tcx>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-#[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub enum InstanceDef<'tcx> {
     /// A user-defined callable item.
     ///
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 980bb8e86155..cc820d9eb2d9 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -1,7 +1,6 @@
 use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use crate::mir::{GeneratorLayout, GeneratorSavedLocal};
 use crate::ty::normalize_erasing_regions::NormalizationError;
-use crate::ty::subst::Subst;
 use crate::ty::{
     self, layout_sanity_check::sanity_check_layout, subst::SubstsRef, EarlyBinder, ReprOptions, Ty,
     TyCtxt, TypeVisitable,
@@ -22,7 +21,7 @@ use rustc_target::abi::call::{
 use rustc_target::abi::*;
 use rustc_target::spec::{abi::Abi as SpecAbi, HasTargetSpec, PanicStrategy, Target};
 
-use std::cmp;
+use std::cmp::{self, Ordering};
 use std::fmt;
 use std::iter;
 use std::num::NonZeroUsize;
@@ -263,6 +262,7 @@ fn layout_of<'tcx>(
     Ok(layout)
 }
 
+#[derive(Clone, Copy)]
 pub struct LayoutCx<'tcx, C> {
     pub tcx: C,
     pub param_env: ty::ParamEnv<'tcx>,
@@ -624,6 +624,14 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                 tcx.intern_layout(self.scalar_pair(data_ptr, metadata))
             }
 
+            ty::Dynamic(_, _, ty::DynStar) => {
+                let mut data = scalar_unit(Int(dl.ptr_sized_integer(), false));
+                data.valid_range_mut().start = 0;
+                let mut vtable = scalar_unit(Pointer);
+                vtable.valid_range_mut().start = 1;
+                tcx.intern_layout(self.scalar_pair(data, vtable))
+            }
+
             // Arrays and slices.
             ty::Array(element, mut count) => {
                 if count.has_projections() {
@@ -678,7 +686,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
 
             // Odd unit types.
             ty::FnDef(..) => univariant(&[], &ReprOptions::default(), StructKind::AlwaysSized)?,
-            ty::Dynamic(..) | ty::Foreign(..) => {
+            ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => {
                 let mut unit = self.univariant_uninterned(
                     ty,
                     &[],
@@ -756,7 +764,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                 // * the element type and length of the single array field, if
                 // the first field is of array type, or
                 //
-                // * the homogenous field type and the number of fields.
+                // * the homogeneous field type and the number of fields.
                 let (e_ty, e_len, is_array) = if let ty::Array(e_ty, _) = f0_ty.kind() {
                     // First ADT field is an array:
 
@@ -1045,131 +1053,191 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                 // that allow representation optimization.)
                 assert!(def.is_enum());
 
-                // The current code for niche-filling relies on variant indices
-                // instead of actual discriminants, so dataful enums with
-                // explicit discriminants (RFC #2363) would misbehave.
-                let no_explicit_discriminants = def
-                    .variants()
-                    .iter_enumerated()
-                    .all(|(i, v)| v.discr == ty::VariantDiscr::Relative(i.as_u32()));
+                // Until we've decided whether to use the tagged or
+                // niche filling LayoutS, we don't want to intern the
+                // variant layouts, so we can't store them in the
+                // overall LayoutS. Store the overall LayoutS
+                // and the variant LayoutSs here until then.
+                struct TmpLayout<'tcx> {
+                    layout: LayoutS<'tcx>,
+                    variants: IndexVec<VariantIdx, LayoutS<'tcx>>,
+                }
 
-                let mut niche_filling_layout = None;
-
-                // Niche-filling enum optimization.
-                if !def.repr().inhibit_enum_layout_opt() && no_explicit_discriminants {
-                    let mut dataful_variant = None;
-                    let mut niche_variants = VariantIdx::MAX..=VariantIdx::new(0);
-
-                    // Find one non-ZST variant.
-                    'variants: for (v, fields) in variants.iter_enumerated() {
-                        if absent(fields) {
-                            continue 'variants;
+                let calculate_niche_filling_layout =
+                    || -> Result<Option<TmpLayout<'tcx>>, LayoutError<'tcx>> {
+                        // The current code for niche-filling relies on variant indices
+                        // instead of actual discriminants, so enums with
+                        // explicit discriminants (RFC #2363) would misbehave.
+                        if def.repr().inhibit_enum_layout_opt()
+                            || def
+                                .variants()
+                                .iter_enumerated()
+                                .any(|(i, v)| v.discr != ty::VariantDiscr::Relative(i.as_u32()))
+                        {
+                            return Ok(None);
                         }
-                        for f in fields {
-                            if !f.is_zst() {
-                                if dataful_variant.is_none() {
-                                    dataful_variant = Some(v);
-                                    continue 'variants;
-                                } else {
-                                    dataful_variant = None;
-                                    break 'variants;
-                                }
-                            }
+
+                        if variants.len() < 2 {
+                            return Ok(None);
                         }
-                        niche_variants = *niche_variants.start().min(&v)..=v;
-                    }
 
-                    if niche_variants.start() > niche_variants.end() {
-                        dataful_variant = None;
-                    }
+                        let mut align = dl.aggregate_align;
+                        let mut variant_layouts = variants
+                            .iter_enumerated()
+                            .map(|(j, v)| {
+                                let mut st = self.univariant_uninterned(
+                                    ty,
+                                    v,
+                                    &def.repr(),
+                                    StructKind::AlwaysSized,
+                                )?;
+                                st.variants = Variants::Single { index: j };
 
-                    if let Some(i) = dataful_variant {
-                        let count = (niche_variants.end().as_u32()
-                            - niche_variants.start().as_u32()
-                            + 1) as u128;
+                                align = align.max(st.align);
+
+                                Ok(st)
+                            })
+                            .collect::<Result<IndexVec<VariantIdx, _>, _>>()?;
+
+                        let largest_variant_index = match variant_layouts
+                            .iter_enumerated()
+                            .max_by_key(|(_i, layout)| layout.size.bytes())
+                            .map(|(i, _layout)| i)
+                        {
+                            None => return Ok(None),
+                            Some(i) => i,
+                        };
+
+                        let all_indices = VariantIdx::new(0)..=VariantIdx::new(variants.len() - 1);
+                        let needs_disc = |index: VariantIdx| {
+                            index != largest_variant_index && !absent(&variants[index])
+                        };
+                        let niche_variants = all_indices.clone().find(|v| needs_disc(*v)).unwrap()
+                            ..=all_indices.rev().find(|v| needs_disc(*v)).unwrap();
+
+                        let count = niche_variants.size_hint().1.unwrap() as u128;
 
                         // Find the field with the largest niche
-                        let niche_candidate = variants[i]
+                        let (field_index, niche, (niche_start, niche_scalar)) = match variants
+                            [largest_variant_index]
                             .iter()
                             .enumerate()
                             .filter_map(|(j, field)| Some((j, field.largest_niche?)))
-                            .max_by_key(|(_, niche)| niche.available(dl));
-
-                        if let Some((field_index, niche, (niche_start, niche_scalar))) =
-                            niche_candidate.and_then(|(field_index, niche)| {
-                                Some((field_index, niche, niche.reserve(self, count)?))
-                            })
+                            .max_by_key(|(_, niche)| niche.available(dl))
+                            .and_then(|(j, niche)| Some((j, niche, niche.reserve(self, count)?)))
                         {
-                            let mut align = dl.aggregate_align;
-                            let st = variants
-                                .iter_enumerated()
-                                .map(|(j, v)| {
-                                    let mut st = self.univariant_uninterned(
-                                        ty,
-                                        v,
-                                        &def.repr(),
-                                        StructKind::AlwaysSized,
-                                    )?;
-                                    st.variants = Variants::Single { index: j };
+                            None => return Ok(None),
+                            Some(x) => x,
+                        };
 
-                                    align = align.max(st.align);
+                        let niche_offset = niche.offset
+                            + variant_layouts[largest_variant_index].fields.offset(field_index);
+                        let niche_size = niche.value.size(dl);
+                        let size = variant_layouts[largest_variant_index].size.align_to(align.abi);
 
-                                    Ok(tcx.intern_layout(st))
-                                })
-                                .collect::<Result<IndexVec<VariantIdx, _>, _>>()?;
+                        let all_variants_fit =
+                            variant_layouts.iter_enumerated_mut().all(|(i, layout)| {
+                                if i == largest_variant_index {
+                                    return true;
+                                }
 
-                            let offset = st[i].fields().offset(field_index) + niche.offset;
+                                layout.largest_niche = None;
 
-                            // Align the total size to the largest alignment.
-                            let size = st[i].size().align_to(align.abi);
+                                if layout.size <= niche_offset {
+                                    // This variant will fit before the niche.
+                                    return true;
+                                }
 
-                            let abi = if st.iter().all(|v| v.abi().is_uninhabited()) {
-                                Abi::Uninhabited
-                            } else if align == st[i].align() && size == st[i].size() {
-                                // When the total alignment and size match, we can use the
-                                // same ABI as the scalar variant with the reserved niche.
-                                match st[i].abi() {
-                                    Abi::Scalar(_) => Abi::Scalar(niche_scalar),
-                                    Abi::ScalarPair(first, second) => {
-                                        // Only the niche is guaranteed to be initialised,
-                                        // so use union layout for the other primitive.
-                                        if offset.bytes() == 0 {
-                                            Abi::ScalarPair(niche_scalar, second.to_union())
-                                        } else {
-                                            Abi::ScalarPair(first.to_union(), niche_scalar)
+                                // Determine if it'll fit after the niche.
+                                let this_align = layout.align.abi;
+                                let this_offset = (niche_offset + niche_size).align_to(this_align);
+
+                                if this_offset + layout.size > size {
+                                    return false;
+                                }
+
+                                // It'll fit, but we need to make some adjustments.
+                                match layout.fields {
+                                    FieldsShape::Arbitrary { ref mut offsets, .. } => {
+                                        for (j, offset) in offsets.iter_mut().enumerate() {
+                                            if !variants[i][j].is_zst() {
+                                                *offset += this_offset;
+                                            }
                                         }
                                     }
-                                    _ => Abi::Aggregate { sized: true },
+                                    _ => {
+                                        panic!("Layout of fields should be Arbitrary for variants")
+                                    }
                                 }
-                            } else {
-                                Abi::Aggregate { sized: true }
-                            };
 
-                            let largest_niche = Niche::from_scalar(dl, offset, niche_scalar);
+                                // It can't be a Scalar or ScalarPair because the offset isn't 0.
+                                if !layout.abi.is_uninhabited() {
+                                    layout.abi = Abi::Aggregate { sized: true };
+                                }
+                                layout.size += this_offset;
 
-                            niche_filling_layout = Some(LayoutS {
-                                variants: Variants::Multiple {
-                                    tag: niche_scalar,
-                                    tag_encoding: TagEncoding::Niche {
-                                        dataful_variant: i,
-                                        niche_variants,
-                                        niche_start,
-                                    },
-                                    tag_field: 0,
-                                    variants: st,
-                                },
-                                fields: FieldsShape::Arbitrary {
-                                    offsets: vec![offset],
-                                    memory_index: vec![0],
-                                },
-                                abi,
-                                largest_niche,
-                                size,
-                                align,
+                                true
                             });
+
+                        if !all_variants_fit {
+                            return Ok(None);
                         }
-                    }
-                }
+
+                        let largest_niche = Niche::from_scalar(dl, niche_offset, niche_scalar);
+
+                        let others_zst = variant_layouts.iter_enumerated().all(|(i, layout)| {
+                            i == largest_variant_index || layout.size == Size::ZERO
+                        });
+                        let same_size = size == variant_layouts[largest_variant_index].size;
+                        let same_align = align == variant_layouts[largest_variant_index].align;
+
+                        let abi = if variant_layouts.iter().all(|v| v.abi.is_uninhabited()) {
+                            Abi::Uninhabited
+                        } else if same_size && same_align && others_zst {
+                            match variant_layouts[largest_variant_index].abi {
+                                // When the total alignment and size match, we can use the
+                                // same ABI as the scalar variant with the reserved niche.
+                                Abi::Scalar(_) => Abi::Scalar(niche_scalar),
+                                Abi::ScalarPair(first, second) => {
+                                    // Only the niche is guaranteed to be initialised,
+                                    // so use union layouts for the other primitive.
+                                    if niche_offset == Size::ZERO {
+                                        Abi::ScalarPair(niche_scalar, second.to_union())
+                                    } else {
+                                        Abi::ScalarPair(first.to_union(), niche_scalar)
+                                    }
+                                }
+                                _ => Abi::Aggregate { sized: true },
+                            }
+                        } else {
+                            Abi::Aggregate { sized: true }
+                        };
+
+                        let layout = LayoutS {
+                            variants: Variants::Multiple {
+                                tag: niche_scalar,
+                                tag_encoding: TagEncoding::Niche {
+                                    untagged_variant: largest_variant_index,
+                                    niche_variants,
+                                    niche_start,
+                                },
+                                tag_field: 0,
+                                variants: IndexVec::new(),
+                            },
+                            fields: FieldsShape::Arbitrary {
+                                offsets: vec![niche_offset],
+                                memory_index: vec![0],
+                            },
+                            abi,
+                            largest_niche,
+                            size,
+                            align,
+                        };
+
+                        Ok(Some(TmpLayout { layout, variants: variant_layouts }))
+                    };
+
+                let niche_filling_layout = calculate_niche_filling_layout()?;
 
                 let (mut min, mut max) = (i128::MAX, i128::MIN);
                 let discr_type = def.repr().discr_type();
@@ -1424,15 +1492,12 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
 
                 let largest_niche = Niche::from_scalar(dl, Size::ZERO, tag);
 
-                let layout_variants =
-                    layout_variants.into_iter().map(|v| tcx.intern_layout(v)).collect();
-
                 let tagged_layout = LayoutS {
                     variants: Variants::Multiple {
                         tag,
                         tag_encoding: TagEncoding::Direct,
                         tag_field: 0,
-                        variants: layout_variants,
+                        variants: IndexVec::new(),
                     },
                     fields: FieldsShape::Arbitrary {
                         offsets: vec![Size::ZERO],
@@ -1444,20 +1509,45 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                     size,
                 };
 
-                let best_layout = match (tagged_layout, niche_filling_layout) {
-                    (tagged_layout, Some(niche_filling_layout)) => {
+                let tagged_layout = TmpLayout { layout: tagged_layout, variants: layout_variants };
+
+                let mut best_layout = match (tagged_layout, niche_filling_layout) {
+                    (tl, Some(nl)) => {
                         // Pick the smaller layout; otherwise,
                         // pick the layout with the larger niche; otherwise,
                         // pick tagged as it has simpler codegen.
-                        cmp::min_by_key(tagged_layout, niche_filling_layout, |layout| {
-                            let niche_size = layout.largest_niche.map_or(0, |n| n.available(dl));
-                            (layout.size, cmp::Reverse(niche_size))
-                        })
+                        use Ordering::*;
+                        let niche_size = |tmp_l: &TmpLayout<'_>| {
+                            tmp_l.layout.largest_niche.map_or(0, |n| n.available(dl))
+                        };
+                        match (
+                            tl.layout.size.cmp(&nl.layout.size),
+                            niche_size(&tl).cmp(&niche_size(&nl)),
+                        ) {
+                            (Greater, _) => nl,
+                            (Equal, Less) => nl,
+                            _ => tl,
+                        }
                     }
-                    (tagged_layout, None) => tagged_layout,
+                    (tl, None) => tl,
                 };
 
-                tcx.intern_layout(best_layout)
+                // Now we can intern the variant layouts and store them in the enum layout.
+                best_layout.layout.variants = match best_layout.layout.variants {
+                    Variants::Multiple { tag, tag_encoding, tag_field, .. } => Variants::Multiple {
+                        tag,
+                        tag_encoding,
+                        tag_field,
+                        variants: best_layout
+                            .variants
+                            .into_iter()
+                            .map(|layout| tcx.intern_layout(layout))
+                            .collect(),
+                    },
+                    _ => bug!(),
+                };
+
+                tcx.intern_layout(best_layout.layout)
             }
 
             // Types with no meaningful known layout.
@@ -2352,7 +2442,9 @@ where
                 | ty::FnDef(..)
                 | ty::GeneratorWitness(..)
                 | ty::Foreign(..)
-                | ty::Dynamic(..) => bug!("TyAndLayout::field({:?}): not applicable", this),
+                | ty::Dynamic(_, _, ty::Dyn) => {
+                    bug!("TyAndLayout::field({:?}): not applicable", this)
+                }
 
                 // Potentially-fat pointers.
                 ty::Ref(_, pointee, _) | ty::RawPtr(ty::TypeAndMut { ty: pointee, .. }) => {
@@ -2381,7 +2473,7 @@ where
 
                     match tcx.struct_tail_erasing_lifetimes(pointee, cx.param_env()).kind() {
                         ty::Slice(_) | ty::Str => TyMaybeWithLayout::Ty(tcx.types.usize),
-                        ty::Dynamic(_, _) => {
+                        ty::Dynamic(_, _, ty::Dyn) => {
                             TyMaybeWithLayout::Ty(tcx.mk_imm_ref(
                                 tcx.lifetimes.re_static,
                                 tcx.mk_array(tcx.types.usize, 3),
@@ -2450,6 +2542,22 @@ where
                     }
                 }
 
+                ty::Dynamic(_, _, ty::DynStar) => {
+                    if i == 0 {
+                        TyMaybeWithLayout::Ty(tcx.types.usize)
+                    } else if i == 1 {
+                        // FIXME(dyn-star) same FIXME as above applies here too
+                        TyMaybeWithLayout::Ty(
+                            tcx.mk_imm_ref(
+                                tcx.lifetimes.re_static,
+                                tcx.mk_array(tcx.types.usize, 3),
+                            ),
+                        )
+                    } else {
+                        bug!("no field {i} on dyn*")
+                    }
+                }
+
                 ty::Projection(_)
                 | ty::Bound(..)
                 | ty::Placeholder(..)
@@ -2558,11 +2666,11 @@ where
                     // using more niches than just null (e.g., the first page of
                     // the address space, or unaligned pointers).
                     Variants::Multiple {
-                        tag_encoding: TagEncoding::Niche { dataful_variant, .. },
+                        tag_encoding: TagEncoding::Niche { untagged_variant, .. },
                         tag_field,
                         ..
                     } if this.fields.offset(tag_field) == offset => {
-                        Some(this.for_variant(cx, dataful_variant))
+                        Some(this.for_variant(cx, untagged_variant))
                     }
                     _ => Some(this),
                 };
@@ -2645,6 +2753,7 @@ impl<'tcx> ty::Instance<'tcx> {
     // for `Instance` (e.g. typeck would use `Ty::fn_sig` instead),
     // or should go through `FnAbi` instead, to avoid losing any
     // adjustments `fn_abi_of_instance` might be performing.
+    #[tracing::instrument(level = "debug", skip(tcx, param_env))]
     fn fn_sig_for_fn_abi(
         &self,
         tcx: TyCtxt<'tcx>,
@@ -2658,9 +2767,14 @@ impl<'tcx> ty::Instance<'tcx> {
                 // (i.e. due to being inside a projection that got normalized, see
                 // `src/test/ui/polymorphization/normalized_sig_types.rs`), and codegen not keeping
                 // track of a polymorphization `ParamEnv` to allow normalizing later.
+                //
+                // We normalize the `fn_sig` again after substituting at a later point.
                 let mut sig = match *ty.kind() {
                     ty::FnDef(def_id, substs) => tcx
-                        .normalize_erasing_regions(tcx.param_env(def_id), tcx.bound_fn_sig(def_id))
+                        .bound_fn_sig(def_id)
+                        .map_bound(|fn_sig| {
+                            tcx.normalize_erasing_regions(tcx.param_env(def_id), fn_sig)
+                        })
                         .subst(tcx, substs),
                     _ => unreachable!(),
                 };
@@ -2791,6 +2905,7 @@ impl<'tcx> ty::Instance<'tcx> {
 /// with `-Cpanic=abort` will look like they can't unwind when in fact they
 /// might (from a foreign exception or similar).
 #[inline]
+#[tracing::instrument(level = "debug", skip(tcx))]
 pub fn fn_can_unwind<'tcx>(tcx: TyCtxt<'tcx>, fn_def_id: Option<DefId>, abi: SpecAbi) -> bool {
     if let Some(did) = fn_def_id {
         // Special attribute for functions which can't unwind.
@@ -3007,6 +3122,7 @@ pub trait FnAbiOf<'tcx>: FnAbiOfHelpers<'tcx> {
     /// NB: that includes virtual calls, which are represented by "direct calls"
     /// to an `InstanceDef::Virtual` instance (of `<dyn Trait as Trait>::fn`).
     #[inline]
+    #[tracing::instrument(level = "debug", skip(self))]
     fn fn_abi_of_instance(
         &self,
         instance: ty::Instance<'tcx>,
@@ -3063,9 +3179,100 @@ fn fn_abi_of_instance<'tcx>(
     )
 }
 
+// Handle safe Rust thin and fat pointers.
+pub fn adjust_for_rust_scalar<'tcx>(
+    cx: LayoutCx<'tcx, TyCtxt<'tcx>>,
+    attrs: &mut ArgAttributes,
+    scalar: Scalar,
+    layout: TyAndLayout<'tcx>,
+    offset: Size,
+    is_return: bool,
+) {
+    // Booleans are always a noundef i1 that needs to be zero-extended.
+    if scalar.is_bool() {
+        attrs.ext(ArgExtension::Zext);
+        attrs.set(ArgAttribute::NoUndef);
+        return;
+    }
+
+    // Scalars which have invalid values cannot be undef.
+    if !scalar.is_always_valid(&cx) {
+        attrs.set(ArgAttribute::NoUndef);
+    }
+
+    // Only pointer types handled below.
+    let Scalar::Initialized { value: Pointer, valid_range} = scalar else { return };
+
+    if !valid_range.contains(0) {
+        attrs.set(ArgAttribute::NonNull);
+    }
+
+    if let Some(pointee) = layout.pointee_info_at(&cx, offset) {
+        if let Some(kind) = pointee.safe {
+            attrs.pointee_align = Some(pointee.align);
+
+            // `Box` (`UniqueBorrowed`) are not necessarily dereferenceable
+            // for the entire duration of the function as they can be deallocated
+            // at any time. Same for shared mutable references. If LLVM had a
+            // way to say "dereferenceable on entry" we could use it here.
+            attrs.pointee_size = match kind {
+                PointerKind::UniqueBorrowed
+                | PointerKind::UniqueBorrowedPinned
+                | PointerKind::Frozen => pointee.size,
+                PointerKind::SharedMutable | PointerKind::UniqueOwned => Size::ZERO,
+            };
+
+            // `Box`, `&T`, and `&mut T` cannot be undef.
+            // Note that this only applies to the value of the pointer itself;
+            // this attribute doesn't make it UB for the pointed-to data to be undef.
+            attrs.set(ArgAttribute::NoUndef);
+
+            // The aliasing rules for `Box<T>` are still not decided, but currently we emit
+            // `noalias` for it. This can be turned off using an unstable flag.
+            // See https://github.com/rust-lang/unsafe-code-guidelines/issues/326
+            let noalias_for_box = cx.tcx.sess.opts.unstable_opts.box_noalias.unwrap_or(true);
+
+            // `&mut` pointer parameters never alias other parameters,
+            // or mutable global data
+            //
+            // `&T` where `T` contains no `UnsafeCell<U>` is immutable,
+            // and can be marked as both `readonly` and `noalias`, as
+            // LLVM's definition of `noalias` is based solely on memory
+            // dependencies rather than pointer equality
+            //
+            // Due to past miscompiles in LLVM, we apply a separate NoAliasMutRef attribute
+            // for UniqueBorrowed arguments, so that the codegen backend can decide whether
+            // or not to actually emit the attribute. It can also be controlled with the
+            // `-Zmutable-noalias` debugging option.
+            let no_alias = match kind {
+                PointerKind::SharedMutable
+                | PointerKind::UniqueBorrowed
+                | PointerKind::UniqueBorrowedPinned => false,
+                PointerKind::UniqueOwned => noalias_for_box,
+                PointerKind::Frozen => !is_return,
+            };
+            if no_alias {
+                attrs.set(ArgAttribute::NoAlias);
+            }
+
+            if kind == PointerKind::Frozen && !is_return {
+                attrs.set(ArgAttribute::ReadOnly);
+            }
+
+            if kind == PointerKind::UniqueBorrowed && !is_return {
+                attrs.set(ArgAttribute::NoAliasMutRef);
+            }
+        }
+    }
+}
+
 impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
     // FIXME(eddyb) perhaps group the signature/type-containing (or all of them?)
     // arguments of this method, into a separate `struct`.
+    #[tracing::instrument(
+        level = "debug",
+        skip(self, caller_location, fn_def_id, force_thin_self_ptr)
+    )]
     fn fn_abi_new_uncached(
         &self,
         sig: ty::PolyFnSig<'tcx>,
@@ -3075,8 +3282,6 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
         // FIXME(eddyb) replace this with something typed, like an `enum`.
         force_thin_self_ptr: bool,
     ) -> Result<&'tcx FnAbi<'tcx, Ty<'tcx>>, FnAbiError<'tcx>> {
-        debug!("fn_abi_new_uncached({:?}, {:?})", sig, extra_args);
-
         let sig = self.tcx.normalize_erasing_late_bound_regions(self.param_env, sig);
 
         let conv = conv_from_spec_abi(self.tcx(), sig.abi);
@@ -3118,92 +3323,9 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
         use SpecAbi::*;
         let rust_abi = matches!(sig.abi, RustIntrinsic | PlatformIntrinsic | Rust | RustCall);
 
-        // Handle safe Rust thin and fat pointers.
-        let adjust_for_rust_scalar = |attrs: &mut ArgAttributes,
-                                      scalar: Scalar,
-                                      layout: TyAndLayout<'tcx>,
-                                      offset: Size,
-                                      is_return: bool| {
-            // Booleans are always a noundef i1 that needs to be zero-extended.
-            if scalar.is_bool() {
-                attrs.ext(ArgExtension::Zext);
-                attrs.set(ArgAttribute::NoUndef);
-                return;
-            }
-
-            // Scalars which have invalid values cannot be undef.
-            if !scalar.is_always_valid(self) {
-                attrs.set(ArgAttribute::NoUndef);
-            }
-
-            // Only pointer types handled below.
-            let Scalar::Initialized { value: Pointer, valid_range} = scalar else { return };
-
-            if !valid_range.contains(0) {
-                attrs.set(ArgAttribute::NonNull);
-            }
-
-            if let Some(pointee) = layout.pointee_info_at(self, offset) {
-                if let Some(kind) = pointee.safe {
-                    attrs.pointee_align = Some(pointee.align);
-
-                    // `Box` (`UniqueBorrowed`) are not necessarily dereferenceable
-                    // for the entire duration of the function as they can be deallocated
-                    // at any time. Same for shared mutable references. If LLVM had a
-                    // way to say "dereferenceable on entry" we could use it here.
-                    attrs.pointee_size = match kind {
-                        PointerKind::UniqueBorrowed
-                        | PointerKind::UniqueBorrowedPinned
-                        | PointerKind::Frozen => pointee.size,
-                        PointerKind::SharedMutable | PointerKind::UniqueOwned => Size::ZERO,
-                    };
-
-                    // `Box`, `&T`, and `&mut T` cannot be undef.
-                    // Note that this only applies to the value of the pointer itself;
-                    // this attribute doesn't make it UB for the pointed-to data to be undef.
-                    attrs.set(ArgAttribute::NoUndef);
-
-                    // The aliasing rules for `Box<T>` are still not decided, but currently we emit
-                    // `noalias` for it. This can be turned off using an unstable flag.
-                    // See https://github.com/rust-lang/unsafe-code-guidelines/issues/326
-                    let noalias_for_box =
-                        self.tcx().sess.opts.unstable_opts.box_noalias.unwrap_or(true);
-
-                    // `&mut` pointer parameters never alias other parameters,
-                    // or mutable global data
-                    //
-                    // `&T` where `T` contains no `UnsafeCell<U>` is immutable,
-                    // and can be marked as both `readonly` and `noalias`, as
-                    // LLVM's definition of `noalias` is based solely on memory
-                    // dependencies rather than pointer equality
-                    //
-                    // Due to past miscompiles in LLVM, we apply a separate NoAliasMutRef attribute
-                    // for UniqueBorrowed arguments, so that the codegen backend can decide whether
-                    // or not to actually emit the attribute. It can also be controlled with the
-                    // `-Zmutable-noalias` debugging option.
-                    let no_alias = match kind {
-                        PointerKind::SharedMutable
-                        | PointerKind::UniqueBorrowed
-                        | PointerKind::UniqueBorrowedPinned => false,
-                        PointerKind::UniqueOwned => noalias_for_box,
-                        PointerKind::Frozen => !is_return,
-                    };
-                    if no_alias {
-                        attrs.set(ArgAttribute::NoAlias);
-                    }
-
-                    if kind == PointerKind::Frozen && !is_return {
-                        attrs.set(ArgAttribute::ReadOnly);
-                    }
-
-                    if kind == PointerKind::UniqueBorrowed && !is_return {
-                        attrs.set(ArgAttribute::NoAliasMutRef);
-                    }
-                }
-            }
-        };
-
         let arg_of = |ty: Ty<'tcx>, arg_idx: Option<usize>| -> Result<_, FnAbiError<'tcx>> {
+            let span = tracing::debug_span!("arg_of");
+            let _entered = span.enter();
             let is_return = arg_idx.is_none();
 
             let layout = self.layout_of(ty)?;
@@ -3218,7 +3340,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
 
             let mut arg = ArgAbi::new(self, layout, |layout, scalar, offset| {
                 let mut attrs = ArgAttributes::new();
-                adjust_for_rust_scalar(&mut attrs, scalar, *layout, offset, is_return);
+                adjust_for_rust_scalar(*self, &mut attrs, scalar, *layout, offset, is_return);
                 attrs
             });
 
@@ -3260,6 +3382,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
         Ok(self.tcx.arena.alloc(fn_abi))
     }
 
+    #[tracing::instrument(level = "trace", skip(self))]
     fn fn_abi_adjust_for_abi(
         &self,
         fn_abi: &mut FnAbi<'tcx, Ty<'tcx>>,
@@ -3334,6 +3457,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
     }
 }
 
+#[tracing::instrument(level = "debug", skip(cx))]
 fn make_thin_self_ptr<'tcx>(
     cx: &(impl HasTyCtxt<'tcx> + HasParamEnv<'tcx>),
     layout: TyAndLayout<'tcx>,
@@ -3345,7 +3469,7 @@ fn make_thin_self_ptr<'tcx>(
         tcx.mk_mut_ptr(layout.ty)
     } else {
         match layout.abi {
-            Abi::ScalarPair(..) => (),
+            Abi::ScalarPair(..) | Abi::Scalar(..) => (),
             _ => bug!("receiver type has unsupported layout: {:?}", layout),
         }
 
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index ed04e7660339..63dd213a0854 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -15,6 +15,7 @@ pub use self::AssocItemContainer::*;
 pub use self::BorrowKind::*;
 pub use self::IntVarValue::*;
 pub use self::Variance::*;
+use crate::error::{OpaqueHiddenTypeMismatch, TypeMismatchReason};
 use crate::metadata::ModChild;
 use crate::middle::privacy::AccessLevels;
 use crate::mir::{Body, GeneratorLayout};
@@ -40,6 +41,7 @@ use rustc_hir::Node;
 use rustc_index::vec::IndexVec;
 use rustc_macros::HashStable;
 use rustc_query_system::ich::StableHashingContext;
+use rustc_serialize::{Decodable, Encodable};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{ExpnId, Span};
@@ -49,10 +51,14 @@ pub use vtable::*;
 
 use std::fmt::Debug;
 use std::hash::{Hash, Hasher};
+use std::marker::PhantomData;
+use std::mem;
+use std::num::NonZeroUsize;
 use std::ops::ControlFlow;
 use std::{fmt, str};
 
 pub use crate::ty::diagnostics::*;
+pub use rustc_type_ir::DynKind::*;
 pub use rustc_type_ir::InferTy::*;
 pub use rustc_type_ir::RegionKind::*;
 pub use rustc_type_ir::TyKind::*;
@@ -67,7 +73,7 @@ pub use self::closure::{
     CAPTURE_STRUCT_LOCAL,
 };
 pub use self::consts::{
-    Const, ConstInt, ConstKind, ConstS, InferConst, ScalarInt, Unevaluated, ValTree,
+    Const, ConstInt, ConstKind, ConstS, InferConst, ScalarInt, UnevaluatedConst, ValTree,
 };
 pub use self::context::{
     tls, CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
@@ -83,9 +89,9 @@ pub use self::sty::BoundRegionKind::*;
 pub use self::sty::{
     Article, Binder, BoundRegion, BoundRegionKind, BoundTy, BoundTyKind, BoundVar,
     BoundVariableKind, CanonicalPolyFnSig, ClosureSubsts, ClosureSubstsParts, ConstVid,
-    EarlyBinder, EarlyBoundRegion, ExistentialPredicate, ExistentialProjection,
-    ExistentialTraitRef, FnSig, FreeRegion, GenSig, GeneratorSubsts, GeneratorSubstsParts,
-    InlineConstSubsts, InlineConstSubstsParts, ParamConst, ParamTy, PolyExistentialProjection,
+    EarlyBoundRegion, ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FnSig,
+    FreeRegion, GenSig, GeneratorSubsts, GeneratorSubstsParts, InlineConstSubsts,
+    InlineConstSubstsParts, ParamConst, ParamTy, PolyExistentialProjection,
     PolyExistentialTraitRef, PolyFnSig, PolyGenSig, PolyTraitRef, ProjectionTy, Region, RegionKind,
     RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts, VarianceDiagInfo,
 };
@@ -178,11 +184,6 @@ pub struct ResolverAstLowering {
     pub label_res_map: NodeMap<ast::NodeId>,
     /// Resolutions for lifetimes.
     pub lifetimes_res_map: NodeMap<LifetimeRes>,
-    /// Mapping from generics `def_id`s to TAIT generics `def_id`s.
-    /// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
-    /// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
-    /// field from the original parameter 'a to the new parameter 'a1.
-    pub generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
     /// Lifetime parameters that lowering will have to introduce.
     pub extra_lifetime_params_map: NodeMap<Vec<(Ident, ast::NodeId, LifetimeRes)>>,
 
@@ -263,11 +264,11 @@ impl fmt::Display for ImplPolarity {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, Encodable, Decodable, HashStable)]
-pub enum Visibility {
+pub enum Visibility<Id = LocalDefId> {
     /// Visible everywhere (including in other crates).
     Public,
     /// Visible only in the given crate-local module.
-    Restricted(DefId),
+    Restricted(Id),
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
@@ -358,28 +359,45 @@ impl<'tcx> DefIdTree for TyCtxt<'tcx> {
     }
 }
 
-impl Visibility {
-    /// Returns `true` if an item with this visibility is accessible from the given block.
-    pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
-        let restriction = match self {
-            // Public items are visible everywhere.
-            Visibility::Public => return true,
-            // Restricted items are visible in an arbitrary local module.
-            Visibility::Restricted(other) if other.krate != module.krate => return false,
-            Visibility::Restricted(module) => module,
-        };
+impl<Id> Visibility<Id> {
+    pub fn is_public(self) -> bool {
+        matches!(self, Visibility::Public)
+    }
 
-        tree.is_descendant_of(module, restriction)
+    pub fn map_id<OutId>(self, f: impl FnOnce(Id) -> OutId) -> Visibility<OutId> {
+        match self {
+            Visibility::Public => Visibility::Public,
+            Visibility::Restricted(id) => Visibility::Restricted(f(id)),
+        }
+    }
+}
+
+impl<Id: Into<DefId>> Visibility<Id> {
+    pub fn to_def_id(self) -> Visibility<DefId> {
+        self.map_id(Into::into)
+    }
+
+    /// Returns `true` if an item with this visibility is accessible from the given module.
+    pub fn is_accessible_from(self, module: impl Into<DefId>, tree: impl DefIdTree) -> bool {
+        match self {
+            // Public items are visible everywhere.
+            Visibility::Public => true,
+            Visibility::Restricted(id) => tree.is_descendant_of(module.into(), id.into()),
+        }
     }
 
     /// Returns `true` if this visibility is at least as accessible as the given visibility
-    pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
-        let vis_restriction = match vis {
-            Visibility::Public => return self == Visibility::Public,
-            Visibility::Restricted(module) => module,
-        };
+    pub fn is_at_least(self, vis: Visibility<impl Into<DefId>>, tree: impl DefIdTree) -> bool {
+        match vis {
+            Visibility::Public => self.is_public(),
+            Visibility::Restricted(id) => self.is_accessible_from(id, tree),
+        }
+    }
+}
 
-        self.is_accessible_from(vis_restriction, tree)
+impl Visibility<DefId> {
+    pub fn expect_local(self) -> Visibility {
+        self.map_id(|id| id.expect_local())
     }
 
     // Returns `true` if this item is visible anywhere in the local crate.
@@ -389,10 +407,6 @@ impl Visibility {
             Visibility::Restricted(def_id) => def_id.is_local(),
         }
     }
-
-    pub fn is_public(self) -> bool {
-        matches!(self, Visibility::Public)
-    }
 }
 
 /// The crate variances map is computed during typeck and contains the
@@ -463,15 +477,6 @@ pub(crate) struct TyS<'tcx> {
     outer_exclusive_binder: ty::DebruijnIndex,
 }
 
-// `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(TyS<'_>, 40);
-
-// We are actually storing a stable hash cache next to the type, so let's
-// also check the full size
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(WithStableHash<TyS<'_>>, 56);
-
 /// Use this rather than `TyS`, whenever possible.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
 #[rustc_diagnostic_item = "Ty"]
@@ -528,10 +533,6 @@ pub(crate) struct PredicateS<'tcx> {
     outer_exclusive_binder: ty::DebruijnIndex,
 }
 
-// This type is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-static_assert_size!(PredicateS<'_>, 56);
-
 /// Use this rather than `PredicateS`, whenever possible.
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
 #[rustc_pass_by_value]
@@ -635,7 +636,7 @@ impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub enum PredicateKind<'tcx> {
     /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
     /// the `Self` type of the trait reference and `A`, `B`, and `C`
@@ -681,7 +682,7 @@ pub enum PredicateKind<'tcx> {
     Coerce(CoercePredicate<'tcx>),
 
     /// Constant initializer must evaluate successfully.
-    ConstEvaluatable(ty::Unevaluated<'tcx, ()>),
+    ConstEvaluatable(ty::UnevaluatedConst<'tcx>),
 
     /// Constants must be equal. The first component is the const that is expected.
     ConstEquate(Const<'tcx>, Const<'tcx>),
@@ -807,7 +808,7 @@ impl<'tcx> Predicate<'tcx> {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct TraitPredicate<'tcx> {
     pub trait_ref: TraitRef<'tcx>,
 
@@ -860,6 +861,11 @@ impl<'tcx> TraitPredicate<'tcx> {
             (BoundConstness::ConstIfConst, hir::Constness::NotConst) => false,
         }
     }
+
+    pub fn without_const(mut self) -> Self {
+        self.constness = BoundConstness::NotConst;
+        self
+    }
 }
 
 impl<'tcx> PolyTraitPredicate<'tcx> {
@@ -887,7 +893,7 @@ impl<'tcx> PolyTraitPredicate<'tcx> {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct OutlivesPredicate<A, B>(pub A, pub B); // `A: B`
 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>;
 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
@@ -898,7 +904,7 @@ pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<'tcx, TypeOutlivesPredicat
 /// whether the `a` type is the type that we should label as "expected" when
 /// presenting user diagnostics.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct SubtypePredicate<'tcx> {
     pub a_is_expected: bool,
     pub a: Ty<'tcx>,
@@ -908,49 +914,142 @@ pub type PolySubtypePredicate<'tcx> = ty::Binder<'tcx, SubtypePredicate<'tcx>>;
 
 /// Encodes that we have to coerce *from* the `a` type to the `b` type.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct CoercePredicate<'tcx> {
     pub a: Ty<'tcx>,
     pub b: Ty<'tcx>,
 }
 pub type PolyCoercePredicate<'tcx> = ty::Binder<'tcx, CoercePredicate<'tcx>>;
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
-pub enum Term<'tcx> {
-    Ty(Ty<'tcx>),
-    Const(Const<'tcx>),
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Term<'tcx> {
+    ptr: NonZeroUsize,
+    marker: PhantomData<(Ty<'tcx>, Const<'tcx>)>,
+}
+
+impl Debug for Term<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let data = if let Some(ty) = self.ty() {
+            format!("Term::Ty({:?})", ty)
+        } else if let Some(ct) = self.ct() {
+            format!("Term::Ct({:?})", ct)
+        } else {
+            unreachable!()
+        };
+        f.write_str(&data)
+    }
 }
 
 impl<'tcx> From<Ty<'tcx>> for Term<'tcx> {
     fn from(ty: Ty<'tcx>) -> Self {
-        Term::Ty(ty)
+        TermKind::Ty(ty).pack()
     }
 }
 
 impl<'tcx> From<Const<'tcx>> for Term<'tcx> {
     fn from(c: Const<'tcx>) -> Self {
-        Term::Const(c)
+        TermKind::Const(c).pack()
+    }
+}
+
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Term<'tcx> {
+    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
+        self.unpack().hash_stable(hcx, hasher);
+    }
+}
+
+impl<'tcx> TypeFoldable<'tcx> for Term<'tcx> {
+    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
+        Ok(self.unpack().try_fold_with(folder)?.pack())
+    }
+}
+
+impl<'tcx> TypeVisitable<'tcx> for Term<'tcx> {
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.unpack().visit_with(visitor)
+    }
+}
+
+impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Term<'tcx> {
+    fn encode(&self, e: &mut E) {
+        self.unpack().encode(e)
+    }
+}
+
+impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Term<'tcx> {
+    fn decode(d: &mut D) -> Self {
+        let res: TermKind<'tcx> = Decodable::decode(d);
+        res.pack()
     }
 }
 
 impl<'tcx> Term<'tcx> {
+    #[inline]
+    pub fn unpack(self) -> TermKind<'tcx> {
+        let ptr = self.ptr.get();
+        // SAFETY: use of `Interned::new_unchecked` here is ok because these
+        // pointers were originally created from `Interned` types in `pack()`,
+        // and this is just going in the other direction.
+        unsafe {
+            match ptr & TAG_MASK {
+                TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
+                    &*((ptr & !TAG_MASK) as *const WithStableHash<ty::TyS<'tcx>>),
+                ))),
+                CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
+                    &*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),
+                ))),
+                _ => core::intrinsics::unreachable(),
+            }
+        }
+    }
+
     pub fn ty(&self) -> Option<Ty<'tcx>> {
-        if let Term::Ty(ty) = self { Some(*ty) } else { None }
+        if let TermKind::Ty(ty) = self.unpack() { Some(ty) } else { None }
     }
 
     pub fn ct(&self) -> Option<Const<'tcx>> {
-        if let Term::Const(c) = self { Some(*c) } else { None }
+        if let TermKind::Const(c) = self.unpack() { Some(c) } else { None }
     }
 
     pub fn into_arg(self) -> GenericArg<'tcx> {
-        match self {
-            Term::Ty(ty) => ty.into(),
-            Term::Const(c) => c.into(),
+        match self.unpack() {
+            TermKind::Ty(ty) => ty.into(),
+            TermKind::Const(c) => c.into(),
         }
     }
 }
 
+const TAG_MASK: usize = 0b11;
+const TYPE_TAG: usize = 0b00;
+const CONST_TAG: usize = 0b01;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable)]
+pub enum TermKind<'tcx> {
+    Ty(Ty<'tcx>),
+    Const(Const<'tcx>),
+}
+
+impl<'tcx> TermKind<'tcx> {
+    #[inline]
+    fn pack(self) -> Term<'tcx> {
+        let (tag, ptr) = match self {
+            TermKind::Ty(ty) => {
+                // Ensure we can use the tag bits.
+                assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
+                (TYPE_TAG, ty.0.0 as *const WithStableHash<ty::TyS<'tcx>> as usize)
+            }
+            TermKind::Const(ct) => {
+                // Ensure we can use the tag bits.
+                assert_eq!(mem::align_of_val(&*ct.0.0) & TAG_MASK, 0);
+                (CONST_TAG, ct.0.0 as *const ty::ConstS<'tcx> as usize)
+            }
+        };
+
+        Term { ptr: unsafe { NonZeroUsize::new_unchecked(ptr | tag) }, marker: PhantomData }
+    }
+}
+
 /// This kind of predicate has no *direct* correspondent in the
 /// syntax, but it roughly corresponds to the syntactic forms:
 ///
@@ -964,7 +1063,7 @@ impl<'tcx> Term<'tcx> {
 /// Form #2 eventually yields one of these `ProjectionPredicate`
 /// instances to normalize the LHS.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct ProjectionPredicate<'tcx> {
     pub projection_ty: ProjectionTy<'tcx>,
     pub term: Term<'tcx>,
@@ -1020,6 +1119,12 @@ pub trait ToPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx>;
 }
 
+impl<'tcx> ToPredicate<'tcx> for Predicate<'tcx> {
+    fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
+        self
+    }
+}
+
 impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
     #[inline(always)]
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
@@ -1184,20 +1289,17 @@ pub struct OpaqueHiddenType<'tcx> {
 impl<'tcx> OpaqueHiddenType<'tcx> {
     pub fn report_mismatch(&self, other: &Self, tcx: TyCtxt<'tcx>) {
         // Found different concrete types for the opaque type.
-        let mut err = tcx.sess.struct_span_err(
-            other.span,
-            "concrete type differs from previous defining opaque type use",
-        );
-        err.span_label(other.span, format!("expected `{}`, got `{}`", self.ty, other.ty));
-        if self.span == other.span {
-            err.span_label(
-                self.span,
-                "this expression supplies two conflicting concrete types for the same opaque type",
-            );
+        let sub_diag = if self.span == other.span {
+            TypeMismatchReason::ConflictType { span: self.span }
         } else {
-            err.span_note(self.span, "previous use here");
-        }
-        err.emit();
+            TypeMismatchReason::PreviousUse { span: self.span }
+        };
+        tcx.sess.emit_err(OpaqueHiddenTypeMismatch {
+            self_ty: self.ty,
+            other_ty: other.ty,
+            other_span: other.span,
+            sub: sub_diag,
+        });
     }
 }
 
@@ -1429,7 +1531,7 @@ impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
         Ok(ParamEnv::new(
             self.caller_bounds().try_fold_with(folder)?,
             self.reveal().try_fold_with(folder)?,
-            self.constness().try_fold_with(folder)?,
+            self.constness(),
         ))
     }
 }
@@ -1437,8 +1539,7 @@ impl<'tcx> TypeFoldable<'tcx> for ParamEnv<'tcx> {
 impl<'tcx> TypeVisitable<'tcx> for ParamEnv<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         self.caller_bounds().visit_with(visitor)?;
-        self.reveal().visit_with(visitor)?;
-        self.constness().visit_with(visitor)
+        self.reveal().visit_with(visitor)
     }
 }
 
@@ -1595,7 +1696,7 @@ impl<'tcx> PolyTraitRef<'tcx> {
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
-#[derive(HashStable)]
+#[derive(HashStable, Lift)]
 pub struct ParamEnvAnd<'tcx, T> {
     pub param_env: ParamEnv<'tcx>,
     pub value: T,
@@ -1797,7 +1898,7 @@ pub enum VariantDiscr {
 pub struct FieldDef {
     pub did: DefId,
     pub name: Symbol,
-    pub vis: Visibility,
+    pub vis: Visibility<DefId>,
 }
 
 impl PartialEq for FieldDef {
@@ -2274,7 +2375,11 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn get_attr(self, did: DefId, attr: Symbol) -> Option<&'tcx ast::Attribute> {
-        self.get_attrs(did, attr).next()
+        if cfg!(debug_assertions) && !rustc_feature::is_valid_for_get_attr(attr) {
+            bug!("get_attr: unexpected called with DefId `{:?}`, attr `{:?}`", did, attr);
+        } else {
+            self.get_attrs(did, attr).next()
+        }
     }
 
     /// Determines whether an item is annotated with an attribute.
@@ -2376,6 +2481,23 @@ impl<'tcx> TyCtxt<'tcx> {
         (ident, scope)
     }
 
+    /// Returns `true` if the debuginfo for `span` should be collapsed to the outermost expansion
+    /// site. Only applies when `Span` is the result of macro expansion.
+    ///
+    /// - If the `collapse_debuginfo` feature is enabled then debuginfo is not collapsed by default
+    ///   and only when a macro definition is annotated with `#[collapse_debuginfo]`.
+    /// - If `collapse_debuginfo` is not enabled, then debuginfo is collapsed by default.
+    ///
+    /// When `-Zdebug-macros` is provided then debuginfo will never be collapsed.
+    pub fn should_collapse_debuginfo(self, span: Span) -> bool {
+        !self.sess.opts.unstable_opts.debug_macros
+            && if self.features().collapse_debuginfo {
+                span.in_macro_expansion_with_collapse_debuginfo()
+            } else {
+                span.from_expansion()
+            }
+    }
+
     pub fn is_object_safe(self, key: DefId) -> bool {
         self.object_safety_violations(key).is_empty()
     }
@@ -2390,6 +2512,14 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn is_const_default_method(self, def_id: DefId) -> bool {
         matches!(self.trait_of_item(def_id), Some(trait_id) if self.has_attr(trait_id, sym::const_trait))
     }
+
+    pub fn impl_trait_in_trait_parent(self, mut def_id: DefId) -> DefId {
+        while let def_kind = self.def_kind(def_id) && def_kind != DefKind::AssocFn {
+            debug_assert_eq!(def_kind, DefKind::ImplTraitPlaceholder);
+            def_id = self.parent(def_id);
+        }
+        def_id
+    }
 }
 
 /// Yields the parent function's `LocalDefId` if `def_id` is an `impl Trait` definition.
@@ -2534,3 +2664,14 @@ pub struct DestructuredConst<'tcx> {
     pub variant: Option<VariantIdx>,
     pub fields: &'tcx [ty::Const<'tcx>],
 }
+
+// Some types are used a lot. Make sure they don't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+mod size_asserts {
+    use super::*;
+    use rustc_data_structures::static_assert_size;
+    // These are in alphabetical order, which is easy to maintain.
+    static_assert_size!(PredicateS<'_>, 48);
+    static_assert_size!(TyS<'_>, 40);
+    static_assert_size!(WithStableHash<TyS<'_>>, 56);
+}
diff --git a/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs b/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
index 9d8a81165943..fe303e21b658 100644
--- a/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
+++ b/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
@@ -10,8 +10,7 @@
 use crate::mir;
 use crate::traits::query::NoSolution;
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder};
-use crate::ty::subst::{Subst, SubstsRef};
-use crate::ty::{self, EarlyBinder, Ty, TyCtxt};
+use crate::ty::{self, EarlyBinder, SubstsRef, Ty, TyCtxt};
 
 #[derive(Debug, Copy, Clone, HashStable, TyEncodable, TyDecodable)]
 pub enum NormalizationError<'tcx> {
@@ -36,6 +35,7 @@ impl<'tcx> TyCtxt<'tcx> {
     ///
     /// This should only be used outside of type inference. For example,
     /// it assumes that normalization will succeed.
+    #[tracing::instrument(level = "debug", skip(self, param_env))]
     pub fn normalize_erasing_regions<T>(self, param_env: ty::ParamEnv<'tcx>, value: T) -> T
     where
         T: TypeFoldable<'tcx>,
@@ -100,6 +100,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// N.B., currently, higher-ranked type bounds inhibit
     /// normalization. Therefore, each time we erase them in
     /// codegen, we need to normalize the contents.
+    #[tracing::instrument(level = "debug", skip(self, param_env))]
     pub fn normalize_erasing_late_bound_regions<T>(
         self,
         param_env: ty::ParamEnv<'tcx>,
@@ -188,13 +189,11 @@ struct NormalizeAfterErasingRegionsFolder<'tcx> {
 }
 
 impl<'tcx> NormalizeAfterErasingRegionsFolder<'tcx> {
-    #[instrument(skip(self), level = "debug")]
     fn normalize_generic_arg_after_erasing_regions(
         &self,
         arg: ty::GenericArg<'tcx>,
     ) -> ty::GenericArg<'tcx> {
         let arg = self.param_env.and(arg);
-        debug!(?arg);
 
         self.tcx.try_normalize_generic_arg_after_erasing_regions(arg).unwrap_or_else(|_| bug!(
                 "Failed to normalize {:?}, maybe try to call `try_normalize_erasing_regions` instead",
diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
index 19b8f27bc95c..9c8dc30e2db3 100644
--- a/compiler/rustc_middle/src/ty/parameterized.rs
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -1,4 +1,4 @@
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, DefIndex};
 use rustc_index::vec::{Idx, IndexVec};
 
 use crate::middle::exported_symbols::ExportedSymbol;
@@ -55,11 +55,12 @@ trivially_parameterized_over_tcx! {
     crate::middle::exported_symbols::SymbolExportInfo,
     crate::middle::resolve_lifetime::ObjectLifetimeDefault,
     crate::mir::ConstQualifs,
+    ty::AssocItemContainer,
     ty::Generics,
     ty::ImplPolarity,
     ty::ReprOptions,
     ty::TraitDef,
-    ty::Visibility,
+    ty::Visibility<DefIndex>,
     ty::adjustment::CoerceUnsizedInfo,
     ty::fast_reject::SimplifiedTypeGen<DefId>,
     rustc_ast::Attribute,
diff --git a/compiler/rustc_middle/src/ty/print/mod.rs b/compiler/rustc_middle/src/ty/print/mod.rs
index d57cf8f01491..e0a8d58f8a7f 100644
--- a/compiler/rustc_middle/src/ty/print/mod.rs
+++ b/compiler/rustc_middle/src/ty/print/mod.rs
@@ -1,4 +1,4 @@
-use crate::ty::subst::{GenericArg, Subst};
+use crate::ty::GenericArg;
 use crate::ty::{self, DefIdTree, Ty, TyCtxt};
 
 use rustc_data_structures::fx::FxHashSet;
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 329478f27b73..70efa748846a 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -1,9 +1,9 @@
 use crate::mir::interpret::{AllocRange, GlobalAlloc, Pointer, Provenance, Scalar};
-use crate::ty::subst::{GenericArg, GenericArgKind, Subst};
 use crate::ty::{
-    self, ConstInt, DefIdTree, ParamConst, ScalarInt, Term, Ty, TyCtxt, TypeFoldable,
+    self, ConstInt, DefIdTree, ParamConst, ScalarInt, Term, TermKind, Ty, TyCtxt, TypeFoldable,
     TypeSuperFoldable, TypeSuperVisitable, TypeVisitable,
 };
+use crate::ty::{GenericArg, GenericArgKind};
 use rustc_apfloat::ieee::{Double, Single};
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::sso::SsoHashSet;
@@ -619,12 +619,16 @@ pub trait PrettyPrinter<'tcx>:
             ty::Adt(def, substs) => {
                 p!(print_def_path(def.did(), substs));
             }
-            ty::Dynamic(data, r) => {
+            ty::Dynamic(data, r, repr) => {
                 let print_r = self.should_print_region(r);
                 if print_r {
                     p!("(");
                 }
-                p!("dyn ", print(data));
+                match repr {
+                    ty::Dyn => p!("dyn "),
+                    ty::DynStar => p!("dyn* "),
+                }
+                p!(print(data));
                 if print_r {
                     p!(" + ", print(r), ")");
                 }
@@ -632,7 +636,13 @@ pub trait PrettyPrinter<'tcx>:
             ty::Foreign(def_id) => {
                 p!(print_def_path(def_id, &[]));
             }
-            ty::Projection(ref data) => p!(print(data)),
+            ty::Projection(ref data) => {
+                if self.tcx().def_kind(data.item_def_id) == DefKind::ImplTraitPlaceholder {
+                    return self.pretty_print_opaque_impl_type(data.item_def_id, data.substs);
+                } else {
+                    p!(print(data))
+                }
+            }
             ty::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)),
             ty::Opaque(def_id, substs) => {
                 // FIXME(eddyb) print this with `print_def_path`.
@@ -855,7 +865,7 @@ pub trait PrettyPrinter<'tcx>:
                         }
 
                         p!(")");
-                        if let Term::Ty(ty) = return_ty.skip_binder() {
+                        if let Some(ty) = return_ty.skip_binder().ty() {
                             if !ty.is_unit() {
                                 p!(" -> ", print(return_ty));
                             }
@@ -916,12 +926,14 @@ pub trait PrettyPrinter<'tcx>:
                         // Skip printing `<[generator@] as Generator<_>>::Return` from async blocks,
                         // unless we can find out what generator return type it comes from.
                         let term = if let Some(ty) = term.skip_binder().ty()
-                            && let ty::Projection(ty::ProjectionTy { item_def_id, substs }) = ty.kind()
-                            && Some(*item_def_id) == tcx.lang_items().generator_return()
+                            && let ty::Projection(proj) = ty.kind()
+                            && let assoc = tcx.associated_item(proj.item_def_id)
+                            && assoc.trait_container(tcx) == tcx.lang_items().gen_trait()
+                            && assoc.name == rustc_span::sym::Return
                         {
                             if let ty::Generator(_, substs, _) = substs.type_at(0).kind() {
                                 let return_ty = substs.as_generator().return_ty();
-                                if !return_ty.is_ty_infer() {
+                                if !return_ty.is_ty_var() {
                                     return_ty.into()
                                 } else {
                                     continue;
@@ -942,13 +954,9 @@ pub trait PrettyPrinter<'tcx>:
 
                         p!(write("{} = ", tcx.associated_item(assoc_item_def_id).name));
 
-                        match term {
-                            Term::Ty(ty) => {
-                                p!(print(ty))
-                            }
-                            Term::Const(c) => {
-                                p!(print(c));
-                            }
+                        match term.unpack() {
+                            TermKind::Ty(ty) => p!(print(ty)),
+                            TermKind::Const(c) => p!(print(c)),
                         };
                     }
 
@@ -1080,17 +1088,9 @@ pub trait PrettyPrinter<'tcx>:
                         .generics_of(principal.def_id)
                         .own_substs_no_defaults(cx.tcx(), principal.substs);
 
-                    // Don't print `'_` if there's no unerased regions.
-                    let print_regions = args.iter().any(|arg| match arg.unpack() {
-                        GenericArgKind::Lifetime(r) => !r.is_erased(),
-                        _ => false,
-                    });
-                    let mut args = args.iter().cloned().filter(|arg| match arg.unpack() {
-                        GenericArgKind::Lifetime(_) => print_regions,
-                        _ => true,
-                    });
                     let mut projections = predicates.projection_bounds();
 
+                    let mut args = args.iter().cloned();
                     let arg0 = args.next();
                     let projection0 = projections.next();
                     if arg0.is_some() || projection0.is_some() {
@@ -1193,15 +1193,7 @@ pub trait PrettyPrinter<'tcx>:
         }
 
         match ct.kind() {
-            ty::ConstKind::Unevaluated(ty::Unevaluated {
-                def,
-                substs,
-                promoted: Some(promoted),
-            }) => {
-                p!(print_value_path(def.did, substs));
-                p!(write("::{:?}", promoted));
-            }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted: None }) => {
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 match self.tcx().def_kind(def.did) {
                     DefKind::Static(..) | DefKind::Const | DefKind::AssocConst => {
                         p!(print_value_path(def.did, substs))
@@ -1401,14 +1393,7 @@ pub trait PrettyPrinter<'tcx>:
     }
 
     fn pretty_print_byte_str(mut self, byte_str: &'tcx [u8]) -> Result<Self::Const, Self::Error> {
-        define_scoped_cx!(self);
-        p!("b\"");
-        for &c in byte_str {
-            for e in std::ascii::escape_default(c) {
-                self.write_char(e as char)?;
-            }
-        }
-        p!("\"");
+        write!(self, "b\"{}\"", byte_str.escape_ascii())?;
         Ok(self)
     }
 
@@ -1577,7 +1562,9 @@ pub struct FmtPrinterData<'a, 'tcx> {
     in_value: bool,
     pub print_alloc_ids: bool,
 
+    // set of all named (non-anonymous) region names
     used_region_names: FxHashSet<Symbol>,
+
     region_index: usize,
     binder_depth: usize,
     printed_type_count: usize,
@@ -1852,22 +1839,11 @@ impl<'tcx> Printer<'tcx> for FmtPrinter<'_, 'tcx> {
     ) -> Result<Self::Path, Self::Error> {
         self = print_prefix(self)?;
 
-        // Don't print `'_` if there's no unerased regions.
-        let print_regions = self.tcx.sess.verbose()
-            || args.iter().any(|arg| match arg.unpack() {
-                GenericArgKind::Lifetime(r) => !r.is_erased(),
-                _ => false,
-            });
-        let args = args.iter().cloned().filter(|arg| match arg.unpack() {
-            GenericArgKind::Lifetime(_) => print_regions,
-            _ => true,
-        });
-
-        if args.clone().next().is_some() {
+        if args.first().is_some() {
             if self.in_value {
                 write!(self, "::")?;
             }
-            self.generic_delimiters(|cx| cx.comma_sep(args))
+            self.generic_delimiters(|cx| cx.comma_sep(args.iter().cloned()))
         } else {
             Ok(self)
         }
@@ -1982,7 +1958,7 @@ impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {
 
             ty::ReVar(_) | ty::ReErased => false,
 
-            ty::ReStatic | ty::ReEmpty(_) => true,
+            ty::ReStatic => true,
         }
     }
 
@@ -2066,14 +2042,6 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
                 p!("'static");
                 return Ok(self);
             }
-            ty::ReEmpty(ty::UniverseIndex::ROOT) => {
-                p!("'<empty>");
-                return Ok(self);
-            }
-            ty::ReEmpty(ui) => {
-                p!(write("'<empty:{:?}>", ui));
-                return Ok(self);
-            }
         }
 
         p!("'_");
@@ -2152,23 +2120,31 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
     where
         T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>,
     {
-        fn name_by_region_index(index: usize) -> Symbol {
-            match index {
-                0 => Symbol::intern("'r"),
-                1 => Symbol::intern("'s"),
-                i => Symbol::intern(&format!("'t{}", i - 2)),
+        fn name_by_region_index(
+            index: usize,
+            available_names: &mut Vec<Symbol>,
+            num_available: usize,
+        ) -> Symbol {
+            if let Some(name) = available_names.pop() {
+                name
+            } else {
+                Symbol::intern(&format!("'z{}", index - num_available))
             }
         }
 
+        debug!("name_all_regions");
+
         // Replace any anonymous late-bound regions with named
         // variants, using new unique identifiers, so that we can
         // clearly differentiate between named and unnamed regions in
         // the output. We'll probably want to tweak this over time to
         // decide just how much information to give.
         if self.binder_depth == 0 {
-            self.prepare_late_bound_region_info(value);
+            self.prepare_region_info(value);
         }
 
+        debug!("self.used_region_names: {:?}", &self.used_region_names);
+
         let mut empty = true;
         let mut start_or_continue = |cx: &mut Self, start: &str, cont: &str| {
             let w = if empty {
@@ -2185,13 +2161,24 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
 
         define_scoped_cx!(self);
 
+        let possible_names =
+            ('a'..='z').rev().map(|s| Symbol::intern(&format!("'{s}"))).collect::<Vec<_>>();
+
+        let mut available_names = possible_names
+            .into_iter()
+            .filter(|name| !self.used_region_names.contains(&name))
+            .collect::<Vec<_>>();
+        debug!(?available_names);
+        let num_available = available_names.len();
+
         let mut region_index = self.region_index;
-        let mut next_name = |this: &Self| loop {
-            let name = name_by_region_index(region_index);
+        let mut next_name = |this: &Self| {
+            let name = name_by_region_index(region_index, &mut available_names, num_available);
+            debug!(?name);
             region_index += 1;
-            if !this.used_region_names.contains(&name) {
-                break name;
-            }
+            assert!(!this.used_region_names.contains(&name));
+
+            name
         };
 
         // If we want to print verbosely, then print *all* binders, even if they
@@ -2212,6 +2199,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
                         ty::BrAnon(_) | ty::BrEnv => {
                             start_or_continue(&mut self, "for<", ", ");
                             let name = next_name(&self);
+                            debug!(?name);
                             do_continue(&mut self, name);
                             ty::BrNamed(CRATE_DEF_ID.to_def_id(), name)
                         }
@@ -2305,29 +2293,37 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
         Ok(inner)
     }
 
-    fn prepare_late_bound_region_info<T>(&mut self, value: &ty::Binder<'tcx, T>)
+    fn prepare_region_info<T>(&mut self, value: &ty::Binder<'tcx, T>)
     where
         T: TypeVisitable<'tcx>,
     {
-        struct LateBoundRegionNameCollector<'a, 'tcx> {
-            used_region_names: &'a mut FxHashSet<Symbol>,
+        struct RegionNameCollector<'tcx> {
+            used_region_names: FxHashSet<Symbol>,
             type_collector: SsoHashSet<Ty<'tcx>>,
         }
 
-        impl<'tcx> ty::visit::TypeVisitor<'tcx> for LateBoundRegionNameCollector<'_, 'tcx> {
+        impl<'tcx> RegionNameCollector<'tcx> {
+            fn new() -> Self {
+                RegionNameCollector {
+                    used_region_names: Default::default(),
+                    type_collector: SsoHashSet::new(),
+                }
+            }
+        }
+
+        impl<'tcx> ty::visit::TypeVisitor<'tcx> for RegionNameCollector<'tcx> {
             type BreakTy = ();
 
             fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
                 trace!("address: {:p}", r.0.0);
-                if let ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name), .. }) = *r {
-                    self.used_region_names.insert(name);
-                } else if let ty::RePlaceholder(ty::PlaceholderRegion {
-                    name: ty::BrNamed(_, name),
-                    ..
-                }) = *r
-                {
+
+                // Collect all named lifetimes. These allow us to prevent duplication
+                // of already existing lifetime names when introducing names for
+                // anonymous late-bound regions.
+                if let Some(name) = r.get_name() {
                     self.used_region_names.insert(name);
                 }
+
                 r.super_visit_with(self)
             }
 
@@ -2343,12 +2339,9 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
             }
         }
 
-        self.used_region_names.clear();
-        let mut collector = LateBoundRegionNameCollector {
-            used_region_names: &mut self.used_region_names,
-            type_collector: SsoHashSet::new(),
-        };
+        let mut collector = RegionNameCollector::new();
         value.visit_with(&mut collector);
+        self.used_region_names = collector.used_region_names;
         self.region_index = 0;
     }
 }
@@ -2608,9 +2601,9 @@ define_print_and_forward_display! {
     }
 
     ty::Term<'tcx> {
-      match self {
-        ty::Term::Ty(ty) => p!(print(ty)),
-        ty::Term::Const(c) => p!(print(c)),
+      match self.unpack() {
+        ty::TermKind::Ty(ty) => p!(print(ty)),
+        ty::TermKind::Const(c) => p!(print(c)),
       }
     }
 
diff --git a/compiler/rustc_middle/src/ty/query.rs b/compiler/rustc_middle/src/ty/query.rs
index 5665bb866d46..169da348a293 100644
--- a/compiler/rustc_middle/src/ty/query.rs
+++ b/compiler/rustc_middle/src/ty/query.rs
@@ -44,6 +44,7 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId};
+use rustc_hir::hir_id::OwnerId;
 use rustc_hir::lang_items::{LangItem, LanguageItems};
 use rustc_hir::{Crate, ItemLocalId, TraitCandidate};
 use rustc_index::{bit_set::FiniteBitSet, vec::IndexVec};
@@ -121,8 +122,8 @@ macro_rules! query_storage {
     ([][$K:ty, $V:ty]) => {
         <DefaultCacheSelector as CacheSelector<$K, $V>>::Cache
     };
-    ([(storage $ty:ty) $($rest:tt)*][$K:ty, $V:ty]) => {
-        <$ty as CacheSelector<$K, $V>>::Cache
+    ([(arena_cache) $($rest:tt)*][$K:ty, $V:ty]) => {
+        <ArenaCacheSelector<'tcx> as CacheSelector<$K, $V>>::Cache
     };
     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
         query_storage!([$($modifiers)*][$($args)*])
@@ -275,8 +276,9 @@ macro_rules! define_callbacks {
             fn default() -> Self {
                 Providers {
                     $($name: |_, key| bug!(
-                        "`tcx.{}({:?})` unsupported by its crate; \
-                         perhaps the `{}` query was never assigned a provider function",
+                        "`tcx.{}({:?})` is not supported for external or local crate;\n
+                        hint: Queries can be either made to the local crate, or the external crate. This error means you tried to use it for one that's not supported (likely the local crate).\n
+                        If that's not the case, {} was likely never assigned to a provider function.\n",
                         stringify!($name),
                         key,
                         stringify!($name),
@@ -335,7 +337,7 @@ macro_rules! define_callbacks {
 rustc_query_append! { define_callbacks! }
 
 mod sealed {
-    use super::{DefId, LocalDefId};
+    use super::{DefId, LocalDefId, OwnerId};
 
     /// An analogue of the `Into` trait that's intended only for query parameters.
     ///
@@ -365,6 +367,13 @@ mod sealed {
             self.to_def_id()
         }
     }
+
+    impl IntoQueryParam<DefId> for OwnerId {
+        #[inline(always)]
+        fn into_query_param(self) -> DefId {
+            self.to_def_id()
+        }
+    }
 }
 
 use sealed::IntoQueryParam;
diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 818affa7113a..cdb618e030af 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -5,8 +5,8 @@
 //! subtyping, type equality, etc.
 
 use crate::ty::error::{ExpectedFound, TypeError};
-use crate::ty::subst::{GenericArg, GenericArgKind, Subst, SubstsRef};
-use crate::ty::{self, ImplSubject, Term, Ty, TyCtxt, TypeFoldable};
+use crate::ty::{self, ImplSubject, Term, TermKind, Ty, TyCtxt, TypeFoldable};
+use crate::ty::{GenericArg, GenericArgKind, SubstsRef};
 use rustc_hir as ast;
 use rustc_hir::def_id::DefId;
 use rustc_span::DUMMY_SP;
@@ -441,7 +441,9 @@ pub fn super_relate_tys<'tcx, R: TypeRelation<'tcx>>(
 
         (&ty::Foreign(a_id), &ty::Foreign(b_id)) if a_id == b_id => Ok(tcx.mk_foreign(a_id)),
 
-        (&ty::Dynamic(a_obj, a_region), &ty::Dynamic(b_obj, b_region)) => {
+        (&ty::Dynamic(a_obj, a_region, a_repr), &ty::Dynamic(b_obj, b_region, b_repr))
+            if a_repr == b_repr =>
+        {
             let region_bound = relation.with_cause(Cause::ExistentialRegionBound, |relation| {
                 relation.relate_with_variance(
                     ty::Contravariant,
@@ -450,7 +452,7 @@ pub fn super_relate_tys<'tcx, R: TypeRelation<'tcx>>(
                     b_region,
                 )
             })?;
-            Ok(tcx.mk_dynamic(relation.relate(a_obj, b_obj)?, region_bound))
+            Ok(tcx.mk_dynamic(relation.relate(a_obj, b_obj)?, region_bound, a_repr))
         }
 
         (&ty::Generator(a_id, a_substs, movability), &ty::Generator(b_id, b_substs, _))
@@ -594,10 +596,6 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
         );
     }
 
-    let eagerly_eval = |x: ty::Const<'tcx>| x.eval(tcx, relation.param_env());
-    let a = eagerly_eval(a);
-    let b = eagerly_eval(b);
-
     // Currently, the values that can be unified are primitive types,
     // and those that derive both `PartialEq` and `Eq`, corresponding
     // to structural-match types.
@@ -617,15 +615,13 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
         (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
             if tcx.features().generic_const_exprs =>
         {
-            tcx.try_unify_abstract_consts(relation.param_env().and((au.shrink(), bu.shrink())))
+            tcx.try_unify_abstract_consts(relation.param_env().and((au, bu)))
         }
 
         // While this is slightly incorrect, it shouldn't matter for `min_const_generics`
         // and is the better alternative to waiting until `generic_const_exprs` can
         // be stabilized.
-        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
-            if au.def == bu.def && au.promoted == bu.promoted =>
-        {
+        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu)) if au.def == bu.def => {
             let substs = relation.relate_with_variance(
                 ty::Variance::Invariant,
                 ty::VarianceDiagInfo::default(),
@@ -633,11 +629,7 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
                 bu.substs,
             )?;
             return Ok(tcx.mk_const(ty::ConstS {
-                kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                    def: au.def,
-                    substs,
-                    promoted: au.promoted,
-                }),
+                kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def: au.def, substs }),
                 ty: a.ty(),
             }));
         }
@@ -803,15 +795,15 @@ impl<'tcx> Relate<'tcx> for ty::TraitPredicate<'tcx> {
     }
 }
 
-impl<'tcx> Relate<'tcx> for ty::Term<'tcx> {
+impl<'tcx> Relate<'tcx> for Term<'tcx> {
     fn relate<R: TypeRelation<'tcx>>(
         relation: &mut R,
         a: Self,
         b: Self,
     ) -> RelateResult<'tcx, Self> {
-        Ok(match (a, b) {
-            (Term::Ty(a), Term::Ty(b)) => relation.relate(a, b)?.into(),
-            (Term::Const(a), Term::Const(b)) => relation.relate(a, b)?.into(),
+        Ok(match (a.unpack(), b.unpack()) {
+            (TermKind::Ty(a), TermKind::Ty(b)) => relation.relate(a, b)?.into(),
+            (TermKind::Const(a), TermKind::Const(b)) => relation.relate(a, b)?.into(),
             _ => return Err(TypeError::Mismatch),
         })
     }
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 57555433f55b..1164cf3e01aa 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -3,13 +3,12 @@
 //! hand, though we've recently added some macros and proc-macros to help with the tedium.
 
 use crate::mir::interpret;
-use crate::mir::ProjectionKind;
+use crate::mir::{Field, ProjectionKind};
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{with_no_trimmed_paths, FmtPrinter, Printer};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
-use crate::ty::{self, InferConst, Lift, Term, Ty, TyCtxt};
+use crate::ty::{self, InferConst, Lift, Term, TermKind, Ty, TyCtxt};
 use rustc_data_structures::functor::IdFunctor;
-use rustc_hir as hir;
 use rustc_hir::def::Namespace;
 use rustc_index::vec::{Idx, IndexVec};
 
@@ -238,12 +237,24 @@ TrivialTypeTraversalAndLiftImpls! {
     crate::ty::Variance,
     ::rustc_span::Span,
     ::rustc_errors::ErrorGuaranteed,
+    Field,
+    interpret::Scalar,
+    rustc_target::abi::Size,
+    ty::DelaySpanBugEmitted,
+    rustc_type_ir::DebruijnIndex,
+    ty::BoundVar,
+    ty::Placeholder<ty::BoundVar>,
+}
+
+TrivialTypeTraversalAndLiftImpls! {
+    for<'tcx> {
+        ty::ValTree<'tcx>,
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////
 // Lift implementations
 
-// FIXME(eddyb) replace all the uses of `Option::map` with `?`.
 impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>> Lift<'tcx> for (A, B) {
     type Lifted = (A::Lifted, B::Lifted);
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
@@ -261,10 +272,10 @@ impl<'tcx, A: Lift<'tcx>, B: Lift<'tcx>, C: Lift<'tcx>> Lift<'tcx> for (A, B, C)
 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Option<T> {
     type Lifted = Option<T::Lifted>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            Some(x) => tcx.lift(x).map(Some),
-            None => Some(None),
-        }
+        Some(match self {
+            Some(x) => Some(tcx.lift(x)?),
+            None => None,
+        })
     }
 }
 
@@ -281,21 +292,21 @@ impl<'tcx, T: Lift<'tcx>, E: Lift<'tcx>> Lift<'tcx> for Result<T, E> {
 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Box<T> {
     type Lifted = Box<T::Lifted>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(*self).map(Box::new)
+        Some(Box::new(tcx.lift(*self)?))
     }
 }
 
 impl<'tcx, T: Lift<'tcx> + Clone> Lift<'tcx> for Rc<T> {
     type Lifted = Rc<T::Lifted>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.as_ref().clone()).map(Rc::new)
+        Some(Rc::new(tcx.lift(self.as_ref().clone())?))
     }
 }
 
 impl<'tcx, T: Lift<'tcx> + Clone> Lift<'tcx> for Arc<T> {
     type Lifted = Arc<T::Lifted>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.as_ref().clone()).map(Arc::new)
+        Some(Arc::new(tcx.lift(self.as_ref().clone())?))
     }
 }
 impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for Vec<T> {
@@ -312,159 +323,18 @@ impl<'tcx, I: Idx, T: Lift<'tcx>> Lift<'tcx> for IndexVec<I, T> {
     }
 }
 
-impl<'a, 'tcx> Lift<'tcx> for ty::TraitRef<'a> {
-    type Lifted = ty::TraitRef<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.substs).map(|substs| ty::TraitRef { def_id: self.def_id, substs })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialTraitRef<'a> {
-    type Lifted = ty::ExistentialTraitRef<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.substs).map(|substs| ty::ExistentialTraitRef { def_id: self.def_id, substs })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialPredicate<'a> {
-    type Lifted = ty::ExistentialPredicate<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            ty::ExistentialPredicate::Trait(x) => tcx.lift(x).map(ty::ExistentialPredicate::Trait),
-            ty::ExistentialPredicate::Projection(x) => {
-                tcx.lift(x).map(ty::ExistentialPredicate::Projection)
-            }
-            ty::ExistentialPredicate::AutoTrait(def_id) => {
-                Some(ty::ExistentialPredicate::AutoTrait(def_id))
-            }
-        }
-    }
-}
-
 impl<'a, 'tcx> Lift<'tcx> for Term<'a> {
     type Lifted = ty::Term<'tcx>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        Some(match self {
-            Term::Ty(ty) => Term::Ty(tcx.lift(ty)?),
-            Term::Const(c) => Term::Const(tcx.lift(c)?),
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::TraitPredicate<'a> {
-    type Lifted = ty::TraitPredicate<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ty::TraitPredicate<'tcx>> {
-        tcx.lift(self.trait_ref).map(|trait_ref| ty::TraitPredicate {
-            trait_ref,
-            constness: self.constness,
-            polarity: self.polarity,
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::SubtypePredicate<'a> {
-    type Lifted = ty::SubtypePredicate<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ty::SubtypePredicate<'tcx>> {
-        tcx.lift((self.a, self.b)).map(|(a, b)| ty::SubtypePredicate {
-            a_is_expected: self.a_is_expected,
-            a,
-            b,
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::CoercePredicate<'a> {
-    type Lifted = ty::CoercePredicate<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ty::CoercePredicate<'tcx>> {
-        tcx.lift((self.a, self.b)).map(|(a, b)| ty::CoercePredicate { a, b })
-    }
-}
-
-impl<'tcx, A: Copy + Lift<'tcx>, B: Copy + Lift<'tcx>> Lift<'tcx> for ty::OutlivesPredicate<A, B> {
-    type Lifted = ty::OutlivesPredicate<A::Lifted, B::Lifted>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift((self.0, self.1)).map(|(a, b)| ty::OutlivesPredicate(a, b))
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionTy<'a> {
-    type Lifted = ty::ProjectionTy<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ty::ProjectionTy<'tcx>> {
-        tcx.lift(self.substs)
-            .map(|substs| ty::ProjectionTy { item_def_id: self.item_def_id, substs })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::ProjectionPredicate<'a> {
-    type Lifted = ty::ProjectionPredicate<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ty::ProjectionPredicate<'tcx>> {
-        tcx.lift((self.projection_ty, self.term))
-            .map(|(projection_ty, term)| ty::ProjectionPredicate { projection_ty, term })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialProjection<'a> {
-    type Lifted = ty::ExistentialProjection<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.substs).map(|substs| ty::ExistentialProjection {
-            substs,
-            term: tcx.lift(self.term).expect("type must lift when substs do"),
-            item_def_id: self.item_def_id,
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::PredicateKind<'a> {
-    type Lifted = ty::PredicateKind<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            ty::PredicateKind::Trait(data) => tcx.lift(data).map(ty::PredicateKind::Trait),
-            ty::PredicateKind::Subtype(data) => tcx.lift(data).map(ty::PredicateKind::Subtype),
-            ty::PredicateKind::Coerce(data) => tcx.lift(data).map(ty::PredicateKind::Coerce),
-            ty::PredicateKind::RegionOutlives(data) => {
-                tcx.lift(data).map(ty::PredicateKind::RegionOutlives)
+        Some(
+            match self.unpack() {
+                TermKind::Ty(ty) => TermKind::Ty(tcx.lift(ty)?),
+                TermKind::Const(c) => TermKind::Const(tcx.lift(c)?),
             }
-            ty::PredicateKind::TypeOutlives(data) => {
-                tcx.lift(data).map(ty::PredicateKind::TypeOutlives)
-            }
-            ty::PredicateKind::Projection(data) => {
-                tcx.lift(data).map(ty::PredicateKind::Projection)
-            }
-            ty::PredicateKind::WellFormed(ty) => tcx.lift(ty).map(ty::PredicateKind::WellFormed),
-            ty::PredicateKind::ClosureKind(closure_def_id, closure_substs, kind) => {
-                tcx.lift(closure_substs).map(|closure_substs| {
-                    ty::PredicateKind::ClosureKind(closure_def_id, closure_substs, kind)
-                })
-            }
-            ty::PredicateKind::ObjectSafe(trait_def_id) => {
-                Some(ty::PredicateKind::ObjectSafe(trait_def_id))
-            }
-            ty::PredicateKind::ConstEvaluatable(uv) => {
-                tcx.lift(uv).map(|uv| ty::PredicateKind::ConstEvaluatable(uv))
-            }
-            ty::PredicateKind::ConstEquate(c1, c2) => {
-                tcx.lift((c1, c2)).map(|(c1, c2)| ty::PredicateKind::ConstEquate(c1, c2))
-            }
-            ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
-                tcx.lift(ty).map(ty::PredicateKind::TypeWellFormedFromEnv)
-            }
-        }
+            .pack(),
+        )
     }
 }
-
-impl<'a, 'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::Binder<'a, T>
-where
-    <T as Lift<'tcx>>::Lifted: TypeVisitable<'tcx>,
-{
-    type Lifted = ty::Binder<'tcx, T::Lifted>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        let bound_vars = tcx.lift(self.bound_vars());
-        tcx.lift(self.skip_binder())
-            .zip(bound_vars)
-            .map(|(value, vars)| ty::Binder::bind_with_vars(value, vars))
-    }
-}
-
 impl<'a, 'tcx> Lift<'tcx> for ty::ParamEnv<'a> {
     type Lifted = ty::ParamEnv<'tcx>;
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
@@ -473,178 +343,6 @@ impl<'a, 'tcx> Lift<'tcx> for ty::ParamEnv<'a> {
     }
 }
 
-impl<'a, 'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::ParamEnvAnd<'a, T> {
-    type Lifted = ty::ParamEnvAnd<'tcx, T::Lifted>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.param_env).and_then(|param_env| {
-            tcx.lift(self.value).map(|value| ty::ParamEnvAnd { param_env, value })
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::ClosureSubsts<'a> {
-    type Lifted = ty::ClosureSubsts<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.substs).map(|substs| ty::ClosureSubsts { substs })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::GeneratorSubsts<'a> {
-    type Lifted = ty::GeneratorSubsts<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.substs).map(|substs| ty::GeneratorSubsts { substs })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjustment<'a> {
-    type Lifted = ty::adjustment::Adjustment<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        let ty::adjustment::Adjustment { kind, target } = self;
-        tcx.lift(kind).and_then(|kind| {
-            tcx.lift(target).map(|target| ty::adjustment::Adjustment { kind, target })
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::Adjust<'a> {
-    type Lifted = ty::adjustment::Adjust<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            ty::adjustment::Adjust::NeverToAny => Some(ty::adjustment::Adjust::NeverToAny),
-            ty::adjustment::Adjust::Pointer(ptr) => Some(ty::adjustment::Adjust::Pointer(ptr)),
-            ty::adjustment::Adjust::Deref(overloaded) => {
-                tcx.lift(overloaded).map(ty::adjustment::Adjust::Deref)
-            }
-            ty::adjustment::Adjust::Borrow(autoref) => {
-                tcx.lift(autoref).map(ty::adjustment::Adjust::Borrow)
-            }
-        }
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::OverloadedDeref<'a> {
-    type Lifted = ty::adjustment::OverloadedDeref<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.region).map(|region| ty::adjustment::OverloadedDeref {
-            region,
-            mutbl: self.mutbl,
-            span: self.span,
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::AutoBorrow<'a> {
-    type Lifted = ty::adjustment::AutoBorrow<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            ty::adjustment::AutoBorrow::Ref(r, m) => {
-                tcx.lift(r).map(|r| ty::adjustment::AutoBorrow::Ref(r, m))
-            }
-            ty::adjustment::AutoBorrow::RawPtr(m) => Some(ty::adjustment::AutoBorrow::RawPtr(m)),
-        }
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::GenSig<'a> {
-    type Lifted = ty::GenSig<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift((self.resume_ty, self.yield_ty, self.return_ty))
-            .map(|(resume_ty, yield_ty, return_ty)| ty::GenSig { resume_ty, yield_ty, return_ty })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::FnSig<'a> {
-    type Lifted = ty::FnSig<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(self.inputs_and_output).map(|x| ty::FnSig {
-            inputs_and_output: x,
-            c_variadic: self.c_variadic,
-            unsafety: self.unsafety,
-            abi: self.abi,
-        })
-    }
-}
-
-impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::error::ExpectedFound<T> {
-    type Lifted = ty::error::ExpectedFound<T::Lifted>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        let ty::error::ExpectedFound { expected, found } = self;
-        tcx.lift(expected).and_then(|expected| {
-            tcx.lift(found).map(|found| ty::error::ExpectedFound { expected, found })
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
-    type Lifted = ty::error::TypeError<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        use crate::ty::error::TypeError::*;
-
-        Some(match self {
-            Mismatch => Mismatch,
-            ConstnessMismatch(x) => ConstnessMismatch(x),
-            PolarityMismatch(x) => PolarityMismatch(x),
-            UnsafetyMismatch(x) => UnsafetyMismatch(x),
-            AbiMismatch(x) => AbiMismatch(x),
-            Mutability => Mutability,
-            ArgumentMutability(i) => ArgumentMutability(i),
-            TupleSize(x) => TupleSize(x),
-            FixedArraySize(x) => FixedArraySize(x),
-            ArgCount => ArgCount,
-            FieldMisMatch(x, y) => FieldMisMatch(x, y),
-            RegionsDoesNotOutlive(a, b) => {
-                return tcx.lift((a, b)).map(|(a, b)| RegionsDoesNotOutlive(a, b));
-            }
-            RegionsInsufficientlyPolymorphic(a, b) => {
-                return tcx.lift(b).map(|b| RegionsInsufficientlyPolymorphic(a, b));
-            }
-            RegionsOverlyPolymorphic(a, b) => {
-                return tcx.lift(b).map(|b| RegionsOverlyPolymorphic(a, b));
-            }
-            RegionsPlaceholderMismatch => RegionsPlaceholderMismatch,
-            IntMismatch(x) => IntMismatch(x),
-            FloatMismatch(x) => FloatMismatch(x),
-            Traits(x) => Traits(x),
-            VariadicMismatch(x) => VariadicMismatch(x),
-            CyclicTy(t) => return tcx.lift(t).map(|t| CyclicTy(t)),
-            CyclicConst(ct) => return tcx.lift(ct).map(|ct| CyclicConst(ct)),
-            ProjectionMismatched(x) => ProjectionMismatched(x),
-            ArgumentSorts(x, i) => return tcx.lift(x).map(|x| ArgumentSorts(x, i)),
-            Sorts(x) => return tcx.lift(x).map(Sorts),
-            ExistentialMismatch(x) => return tcx.lift(x).map(ExistentialMismatch),
-            ConstMismatch(x) => return tcx.lift(x).map(ConstMismatch),
-            IntrinsicCast => IntrinsicCast,
-            TargetFeatureCast(x) => TargetFeatureCast(x),
-            ObjectUnsafeCoercion(x) => return tcx.lift(x).map(ObjectUnsafeCoercion),
-        })
-    }
-}
-
-impl<'a, 'tcx> Lift<'tcx> for ty::InstanceDef<'a> {
-    type Lifted = ty::InstanceDef<'tcx>;
-    fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        match self {
-            ty::InstanceDef::Item(def_id) => Some(ty::InstanceDef::Item(def_id)),
-            ty::InstanceDef::VTableShim(def_id) => Some(ty::InstanceDef::VTableShim(def_id)),
-            ty::InstanceDef::ReifyShim(def_id) => Some(ty::InstanceDef::ReifyShim(def_id)),
-            ty::InstanceDef::Intrinsic(def_id) => Some(ty::InstanceDef::Intrinsic(def_id)),
-            ty::InstanceDef::FnPtrShim(def_id, ty) => {
-                Some(ty::InstanceDef::FnPtrShim(def_id, tcx.lift(ty)?))
-            }
-            ty::InstanceDef::Virtual(def_id, n) => Some(ty::InstanceDef::Virtual(def_id, n)),
-            ty::InstanceDef::ClosureOnceShim { call_once, track_caller } => {
-                Some(ty::InstanceDef::ClosureOnceShim { call_once, track_caller })
-            }
-            ty::InstanceDef::DropGlue(def_id, ty) => {
-                Some(ty::InstanceDef::DropGlue(def_id, tcx.lift(ty)?))
-            }
-            ty::InstanceDef::CloneShim(def_id, ty) => {
-                Some(ty::InstanceDef::CloneShim(def_id, tcx.lift(ty)?))
-            }
-        }
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////
 // TypeFoldable implementations.
 
@@ -862,18 +560,6 @@ impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for Box<[T]> {
     }
 }
 
-impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::EarlyBinder<T> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        self.try_map_bound(|ty| ty.try_fold_with(folder))
-    }
-}
-
-impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for ty::EarlyBinder<T> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.as_ref().0.visit_with(visitor)
-    }
-}
-
 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<'tcx, T> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         folder.try_fold_binder(self)
@@ -907,88 +593,12 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::Binder<'tcx, ty::Existentia
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx>
-    for &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>
-{
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.iter().try_for_each(|p| p.visit_with(visitor))
-    }
-}
-
 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ProjectionKind> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         ty::util::fold_list(self, folder, |tcx, v| tcx.intern_projs(v))
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<ProjectionKind> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.iter().try_for_each(|t| t.visit_with(visitor))
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for ty::instance::Instance<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        use crate::ty::InstanceDef::*;
-        Ok(Self {
-            substs: self.substs.try_fold_with(folder)?,
-            def: match self.def {
-                Item(def) => Item(def.try_fold_with(folder)?),
-                VTableShim(did) => VTableShim(did.try_fold_with(folder)?),
-                ReifyShim(did) => ReifyShim(did.try_fold_with(folder)?),
-                Intrinsic(did) => Intrinsic(did.try_fold_with(folder)?),
-                FnPtrShim(did, ty) => {
-                    FnPtrShim(did.try_fold_with(folder)?, ty.try_fold_with(folder)?)
-                }
-                Virtual(did, i) => Virtual(did.try_fold_with(folder)?, i),
-                ClosureOnceShim { call_once, track_caller } => {
-                    ClosureOnceShim { call_once: call_once.try_fold_with(folder)?, track_caller }
-                }
-                DropGlue(did, ty) => {
-                    DropGlue(did.try_fold_with(folder)?, ty.try_fold_with(folder)?)
-                }
-                CloneShim(did, ty) => {
-                    CloneShim(did.try_fold_with(folder)?, ty.try_fold_with(folder)?)
-                }
-            },
-        })
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for ty::instance::Instance<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        use crate::ty::InstanceDef::*;
-        self.substs.visit_with(visitor)?;
-        match self.def {
-            Item(def) => def.visit_with(visitor),
-            VTableShim(did) | ReifyShim(did) | Intrinsic(did) | Virtual(did, _) => {
-                did.visit_with(visitor)
-            }
-            FnPtrShim(did, ty) | CloneShim(did, ty) => {
-                did.visit_with(visitor)?;
-                ty.visit_with(visitor)
-            }
-            DropGlue(did, ty) => {
-                did.visit_with(visitor)?;
-                ty.visit_with(visitor)
-            }
-            ClosureOnceShim { call_once, track_caller: _ } => call_once.visit_with(visitor),
-        }
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for interpret::GlobalId<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(Self { instance: self.instance.try_fold_with(folder)?, promoted: self.promoted })
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for interpret::GlobalId<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.instance.visit_with(visitor)
-    }
-}
-
 impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         folder.try_fold_ty(self)
@@ -1011,9 +621,11 @@ impl<'tcx> TypeSuperFoldable<'tcx> for Ty<'tcx> {
             ty::Array(typ, sz) => ty::Array(typ.try_fold_with(folder)?, sz.try_fold_with(folder)?),
             ty::Slice(typ) => ty::Slice(typ.try_fold_with(folder)?),
             ty::Adt(tid, substs) => ty::Adt(tid, substs.try_fold_with(folder)?),
-            ty::Dynamic(trait_ty, region) => {
-                ty::Dynamic(trait_ty.try_fold_with(folder)?, region.try_fold_with(folder)?)
-            }
+            ty::Dynamic(trait_ty, region, representation) => ty::Dynamic(
+                trait_ty.try_fold_with(folder)?,
+                region.try_fold_with(folder)?,
+                representation,
+            ),
             ty::Tuple(ts) => ty::Tuple(ts.try_fold_with(folder)?),
             ty::FnDef(def_id, substs) => ty::FnDef(def_id, substs.try_fold_with(folder)?),
             ty::FnPtr(f) => ty::FnPtr(f.try_fold_with(folder)?),
@@ -1057,7 +669,7 @@ impl<'tcx> TypeSuperVisitable<'tcx> for Ty<'tcx> {
             }
             ty::Slice(typ) => typ.visit_with(visitor),
             ty::Adt(_, substs) => substs.visit_with(visitor),
-            ty::Dynamic(ref trait_ty, ref reg) => {
+            ty::Dynamic(ref trait_ty, ref reg, _) => {
                 trait_ty.visit_with(visitor)?;
                 reg.visit_with(visitor)
             }
@@ -1162,12 +774,6 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::Predicate<'tcx>> {
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<ty::Predicate<'tcx>> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.iter().try_for_each(|p| p.visit_with(visitor))
-    }
-}
-
 impl<'tcx, T: TypeFoldable<'tcx>, I: Idx> TypeFoldable<'tcx> for IndexVec<I, T> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         self.try_map_id(|x| x.try_fold_with(folder))
@@ -1214,34 +820,6 @@ impl<'tcx> TypeSuperVisitable<'tcx> for ty::Const<'tcx> {
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for ty::ConstKind<'tcx> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(match self {
-            ty::ConstKind::Infer(ic) => ty::ConstKind::Infer(ic.try_fold_with(folder)?),
-            ty::ConstKind::Param(p) => ty::ConstKind::Param(p.try_fold_with(folder)?),
-            ty::ConstKind::Unevaluated(uv) => ty::ConstKind::Unevaluated(uv.try_fold_with(folder)?),
-            ty::ConstKind::Value(_)
-            | ty::ConstKind::Bound(..)
-            | ty::ConstKind::Placeholder(..)
-            | ty::ConstKind::Error(_) => self,
-        })
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for ty::ConstKind<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        match *self {
-            ty::ConstKind::Infer(ic) => ic.visit_with(visitor),
-            ty::ConstKind::Param(p) => p.visit_with(visitor),
-            ty::ConstKind::Unevaluated(uv) => uv.visit_with(visitor),
-            ty::ConstKind::Value(_)
-            | ty::ConstKind::Bound(..)
-            | ty::ConstKind::Placeholder(_)
-            | ty::ConstKind::Error(_) => ControlFlow::CONTINUE,
-        }
-    }
-}
-
 impl<'tcx> TypeFoldable<'tcx> for InferConst<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _folder: &mut F) -> Result<Self, F::Error> {
         Ok(self)
@@ -1254,57 +832,29 @@ impl<'tcx> TypeVisitable<'tcx> for InferConst<'tcx> {
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeFoldable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        folder.try_fold_unevaluated(self)
+        folder.try_fold_ty_unevaluated(self)
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeVisitable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        visitor.visit_unevaluated(*self)
+        visitor.visit_ty_unevaluated(*self)
     }
 }
 
-impl<'tcx> TypeSuperFoldable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeSuperFoldable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
         self,
         folder: &mut F,
     ) -> Result<Self, F::Error> {
-        Ok(ty::Unevaluated {
-            def: self.def,
-            substs: self.substs.try_fold_with(folder)?,
-            promoted: self.promoted,
-        })
+        Ok(ty::UnevaluatedConst { def: self.def, substs: self.substs.try_fold_with(folder)? })
     }
 }
 
-impl<'tcx> TypeSuperVisitable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeSuperVisitable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         self.substs.visit_with(visitor)
     }
 }
-
-impl<'tcx> TypeFoldable<'tcx> for ty::Unevaluated<'tcx, ()> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(self.expand().try_fold_with(folder)?.shrink())
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for ty::Unevaluated<'tcx, ()> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.expand().visit_with(visitor)
-    }
-}
-
-impl<'tcx> TypeFoldable<'tcx> for hir::Constness {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, _: &mut F) -> Result<Self, F::Error> {
-        Ok(self)
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for hir::Constness {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
-    }
-}
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 80354a3f8a22..f4f4bb37c1ac 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -3,7 +3,7 @@
 #![allow(rustc::usage_of_ty_tykind)]
 
 use crate::infer::canonical::Canonical;
-use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
+use crate::ty::subst::{GenericArg, InternalSubsts, SubstsRef};
 use crate::ty::visit::ValidateBoundVars;
 use crate::ty::InferTy::*;
 use crate::ty::{
@@ -11,6 +11,7 @@ use crate::ty::{
     TypeVisitor,
 };
 use crate::ty::{List, ParamEnv};
+use hir::def::DefKind;
 use polonius_engine::Atom;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::intern::Interned;
@@ -18,7 +19,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_index::vec::Idx;
 use rustc_macros::HashStable;
-use rustc_span::symbol::{kw, Symbol};
+use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_target::abi::VariantIdx;
 use rustc_target::spec::abi;
 use std::borrow::Cow;
@@ -84,6 +85,17 @@ impl BoundRegionKind {
             _ => false,
         }
     }
+
+    pub fn get_name(&self) -> Option<Symbol> {
+        if self.is_named() {
+            match *self {
+                BoundRegionKind::BrNamed(_, name) => return Some(name),
+                _ => unreachable!(),
+            }
+        }
+
+        None
+    }
 }
 
 pub trait Article {
@@ -201,7 +213,7 @@ static_assert_size!(TyKind<'_>, 32);
 /// * `GR`: The "return type", which is the type of value returned upon
 ///   completion of the generator.
 /// * `GW`: The "generator witness".
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
 pub struct ClosureSubsts<'tcx> {
     /// Lifetime and type parameters from the enclosing function,
     /// concatenated with a tuple containing the types of the upvars.
@@ -332,7 +344,7 @@ impl<'tcx> ClosureSubsts<'tcx> {
 }
 
 /// Similar to `ClosureSubsts`; see the above documentation for more.
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
 pub struct GeneratorSubsts<'tcx> {
     pub substs: SubstsRef<'tcx>,
 }
@@ -550,7 +562,7 @@ impl<'tcx> GeneratorSubsts<'tcx> {
         layout.variant_fields.iter().map(move |variant| {
             variant
                 .iter()
-                .map(move |field| EarlyBinder(layout.field_tys[*field]).subst(tcx, self.substs))
+                .map(move |field| ty::EarlyBinder(layout.field_tys[*field]).subst(tcx, self.substs))
         })
     }
 
@@ -659,7 +671,7 @@ impl<'tcx> InlineConstSubsts<'tcx> {
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Ord, Eq, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub enum ExistentialPredicate<'tcx> {
     /// E.g., `Iterator`.
     Trait(ExistentialTraitRef<'tcx>),
@@ -691,6 +703,9 @@ impl<'tcx> ExistentialPredicate<'tcx> {
 }
 
 impl<'tcx> Binder<'tcx, ExistentialPredicate<'tcx>> {
+    /// Given an existential predicate like `?Self: PartialEq<u32>` (e.g., derived from `dyn PartialEq<u32>`),
+    /// and a concrete type `self_ty`, returns a full predicate where the existentially quantified variable `?Self`
+    /// has been replaced with `self_ty` (e.g., `self_ty: PartialEq<u32>`, in our example).
     pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::Predicate<'tcx> {
         use crate::ty::ToPredicate;
         match self.skip_binder() {
@@ -785,7 +800,7 @@ impl<'tcx> List<ty::Binder<'tcx, ExistentialPredicate<'tcx>>> {
 /// Trait references also appear in object types like `Foo<U>`, but in
 /// that case the `Self` parameter is absent from the substitutions.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct TraitRef<'tcx> {
     pub def_id: DefId,
     pub substs: SubstsRef<'tcx>,
@@ -849,6 +864,12 @@ impl<'tcx> PolyTraitRef<'tcx> {
     }
 }
 
+impl rustc_errors::IntoDiagnosticArg for PolyTraitRef<'_> {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        self.to_string().into_diagnostic_arg()
+    }
+}
+
 /// An existential reference to a trait, where `Self` is erased.
 /// For example, the trait object `Trait<'a, 'b, X, Y>` is:
 /// ```ignore (illustrative)
@@ -857,7 +878,7 @@ impl<'tcx> PolyTraitRef<'tcx> {
 /// The substitutions don't include the erased `Self`, only trait
 /// type and lifetime parameters (`[X, Y]` and `['a, 'b]` above).
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct ExistentialTraitRef<'tcx> {
     pub def_id: DefId,
     pub substs: SubstsRef<'tcx>,
@@ -905,73 +926,6 @@ impl<'tcx> PolyExistentialTraitRef<'tcx> {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-#[derive(Encodable, Decodable, HashStable)]
-pub struct EarlyBinder<T>(pub T);
-
-impl<T> EarlyBinder<T> {
-    pub fn as_ref(&self) -> EarlyBinder<&T> {
-        EarlyBinder(&self.0)
-    }
-
-    pub fn map_bound_ref<F, U>(&self, f: F) -> EarlyBinder<U>
-    where
-        F: FnOnce(&T) -> U,
-    {
-        self.as_ref().map_bound(f)
-    }
-
-    pub fn map_bound<F, U>(self, f: F) -> EarlyBinder<U>
-    where
-        F: FnOnce(T) -> U,
-    {
-        let value = f(self.0);
-        EarlyBinder(value)
-    }
-
-    pub fn try_map_bound<F, U, E>(self, f: F) -> Result<EarlyBinder<U>, E>
-    where
-        F: FnOnce(T) -> Result<U, E>,
-    {
-        let value = f(self.0)?;
-        Ok(EarlyBinder(value))
-    }
-
-    pub fn rebind<U>(&self, value: U) -> EarlyBinder<U> {
-        EarlyBinder(value)
-    }
-}
-
-impl<T> EarlyBinder<Option<T>> {
-    pub fn transpose(self) -> Option<EarlyBinder<T>> {
-        self.0.map(|v| EarlyBinder(v))
-    }
-}
-
-impl<T, U> EarlyBinder<(T, U)> {
-    pub fn transpose_tuple2(self) -> (EarlyBinder<T>, EarlyBinder<U>) {
-        (EarlyBinder(self.0.0), EarlyBinder(self.0.1))
-    }
-}
-
-pub struct EarlyBinderIter<T> {
-    t: T,
-}
-
-impl<T: IntoIterator> EarlyBinder<T> {
-    pub fn transpose_iter(self) -> EarlyBinderIter<T::IntoIter> {
-        EarlyBinderIter { t: self.0.into_iter() }
-    }
-}
-
-impl<T: Iterator> Iterator for EarlyBinderIter<T> {
-    type Item = EarlyBinder<T::Item>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.t.next().map(|i| EarlyBinder(i))
-    }
-}
-
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
 #[derive(HashStable)]
 pub enum BoundVariableKind {
@@ -1013,7 +967,7 @@ impl BoundVariableKind {
 ///
 /// `Decodable` and `Encodable` are implemented for `Binder<T>` using the `impl_binder_encode_decode!` macro.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-#[derive(HashStable)]
+#[derive(HashStable, Lift)]
 pub struct Binder<'tcx, T>(T, &'tcx List<BoundVariableKind>);
 
 impl<'tcx, T> Binder<'tcx, T>
@@ -1175,7 +1129,7 @@ impl<'tcx, T> Binder<'tcx, Option<T>> {
 /// Represents the projection of an associated type. In explicit UFCS
 /// form this would be written `<T as Trait<..>>::N`.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct ProjectionTy<'tcx> {
     /// The parameters of the associated item.
     pub substs: SubstsRef<'tcx>,
@@ -1190,7 +1144,13 @@ pub struct ProjectionTy<'tcx> {
 
 impl<'tcx> ProjectionTy<'tcx> {
     pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
-        tcx.parent(self.item_def_id)
+        match tcx.def_kind(self.item_def_id) {
+            DefKind::AssocTy | DefKind::AssocConst => tcx.parent(self.item_def_id),
+            DefKind::ImplTraitPlaceholder => {
+                tcx.parent(tcx.impl_trait_in_trait_parent(self.item_def_id))
+            }
+            kind => bug!("unexpected DefKind in ProjectionTy: {kind:?}"),
+        }
     }
 
     /// Extracts the underlying trait reference and own substs from this projection.
@@ -1225,7 +1185,7 @@ impl<'tcx> ProjectionTy<'tcx> {
     }
 }
 
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
 pub struct GenSig<'tcx> {
     pub resume_ty: Ty<'tcx>,
     pub yield_ty: Ty<'tcx>,
@@ -1241,7 +1201,7 @@ pub type PolyGenSig<'tcx> = Binder<'tcx, GenSig<'tcx>>;
 /// - `output`: is the return type.
 /// - `c_variadic`: indicates whether this is a C-variadic function.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct FnSig<'tcx> {
     pub inputs_and_output: &'tcx List<Ty<'tcx>>,
     pub c_variadic: bool,
@@ -1423,7 +1383,7 @@ impl From<BoundVar> for BoundTy {
 
 /// A `ProjectionPredicate` for an `ExistentialTraitRef`.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct ExistentialProjection<'tcx> {
     pub item_def_id: DefId,
     pub substs: SubstsRef<'tcx>,
@@ -1496,6 +1456,23 @@ impl<'tcx> Region<'tcx> {
         *self.0.0
     }
 
+    pub fn get_name(self) -> Option<Symbol> {
+        if self.has_name() {
+            let name = match *self {
+                ty::ReEarlyBound(ebr) => Some(ebr.name),
+                ty::ReLateBound(_, br) => br.kind.get_name(),
+                ty::ReFree(fr) => fr.bound_region.get_name(),
+                ty::ReStatic => Some(kw::StaticLifetime),
+                ty::RePlaceholder(placeholder) => placeholder.name.get_name(),
+                _ => None,
+            };
+
+            return name;
+        }
+
+        None
+    }
+
     /// Is this region named by the user?
     pub fn has_name(self) -> bool {
         match *self {
@@ -1505,7 +1482,6 @@ impl<'tcx> Region<'tcx> {
             ty::ReStatic => true,
             ty::ReVar(..) => false,
             ty::RePlaceholder(placeholder) => placeholder.name.is_named(),
-            ty::ReEmpty(_) => false,
             ty::ReErased => false,
         }
     }
@@ -1530,11 +1506,6 @@ impl<'tcx> Region<'tcx> {
         matches!(*self, ty::RePlaceholder(..))
     }
 
-    #[inline]
-    pub fn is_empty(self) -> bool {
-        matches!(*self, ty::ReEmpty(..))
-    }
-
     #[inline]
     pub fn bound_at_or_above_binder(self, index: ty::DebruijnIndex) -> bool {
         match *self {
@@ -1566,7 +1537,7 @@ impl<'tcx> Region<'tcx> {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
                 flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS;
             }
-            ty::ReEmpty(_) | ty::ReStatic => {
+            ty::ReStatic => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
             }
             ty::ReLateBound(..) => {
@@ -1846,7 +1817,12 @@ impl<'tcx> Ty<'tcx> {
 
     #[inline]
     pub fn is_trait(self) -> bool {
-        matches!(self.kind(), Dynamic(..))
+        matches!(self.kind(), Dynamic(_, _, ty::Dyn))
+    }
+
+    #[inline]
+    pub fn is_dyn_star(self) -> bool {
+        matches!(self.kind(), Dynamic(_, _, ty::DynStar))
     }
 
     #[inline]
@@ -2263,6 +2239,35 @@ impl<'tcx> Ty<'tcx> {
             }
         }
     }
+
+    // If `self` is a primitive, return its [`Symbol`].
+    pub fn primitive_symbol(self) -> Option<Symbol> {
+        match self.kind() {
+            ty::Bool => Some(sym::bool),
+            ty::Char => Some(sym::char),
+            ty::Float(f) => match f {
+                ty::FloatTy::F32 => Some(sym::f32),
+                ty::FloatTy::F64 => Some(sym::f64),
+            },
+            ty::Int(f) => match f {
+                ty::IntTy::Isize => Some(sym::isize),
+                ty::IntTy::I8 => Some(sym::i8),
+                ty::IntTy::I16 => Some(sym::i16),
+                ty::IntTy::I32 => Some(sym::i32),
+                ty::IntTy::I64 => Some(sym::i64),
+                ty::IntTy::I128 => Some(sym::i128),
+            },
+            ty::Uint(f) => match f {
+                ty::UintTy::Usize => Some(sym::usize),
+                ty::UintTy::U8 => Some(sym::u8),
+                ty::UintTy::U16 => Some(sym::u16),
+                ty::UintTy::U32 => Some(sym::u32),
+                ty::UintTy::U64 => Some(sym::u64),
+                ty::UintTy::U128 => Some(sym::u128),
+            },
+            _ => None,
+        }
+    }
 }
 
 /// Extra information about why we ended up with a particular variance.
diff --git a/compiler/rustc_middle/src/ty/subst.rs b/compiler/rustc_middle/src/ty/subst.rs
index 6262aa180757..a939be32fff3 100644
--- a/compiler/rustc_middle/src/ty/subst.rs
+++ b/compiler/rustc_middle/src/ty/subst.rs
@@ -459,12 +459,6 @@ impl<'tcx> TypeFoldable<'tcx> for SubstsRef<'tcx> {
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for SubstsRef<'tcx> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.iter().try_for_each(|t| t.visit_with(visitor))
-    }
-}
-
 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<Ty<'tcx>> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         // This code is fairly hot, though not as hot as `SubstsRef`.
@@ -497,24 +491,85 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<Ty<'tcx>> {
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<Ty<'tcx>> {
+impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for &'tcx ty::List<T> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         self.iter().try_for_each(|t| t.visit_with(visitor))
     }
 }
 
-// Just call `foo.subst(tcx, substs)` to perform a substitution across `foo`.
-#[rustc_on_unimplemented(message = "Calling `subst` must now be done through an `EarlyBinder`")]
-pub trait Subst<'tcx>: Sized {
-    type Inner;
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Encodable, Decodable, HashStable)]
+pub struct EarlyBinder<T>(pub T);
 
-    fn subst(self, tcx: TyCtxt<'tcx>, substs: &[GenericArg<'tcx>]) -> Self::Inner;
+/// For early binders, you should first call `subst` before using any visitors.
+impl<'tcx, T> !TypeFoldable<'tcx> for ty::EarlyBinder<T> {}
+impl<'tcx, T> !TypeVisitable<'tcx> for ty::EarlyBinder<T> {}
+
+impl<T> EarlyBinder<T> {
+    pub fn as_ref(&self) -> EarlyBinder<&T> {
+        EarlyBinder(&self.0)
+    }
+
+    pub fn map_bound_ref<F, U>(&self, f: F) -> EarlyBinder<U>
+    where
+        F: FnOnce(&T) -> U,
+    {
+        self.as_ref().map_bound(f)
+    }
+
+    pub fn map_bound<F, U>(self, f: F) -> EarlyBinder<U>
+    where
+        F: FnOnce(T) -> U,
+    {
+        let value = f(self.0);
+        EarlyBinder(value)
+    }
+
+    pub fn try_map_bound<F, U, E>(self, f: F) -> Result<EarlyBinder<U>, E>
+    where
+        F: FnOnce(T) -> Result<U, E>,
+    {
+        let value = f(self.0)?;
+        Ok(EarlyBinder(value))
+    }
+
+    pub fn rebind<U>(&self, value: U) -> EarlyBinder<U> {
+        EarlyBinder(value)
+    }
 }
 
-impl<'tcx, T: TypeFoldable<'tcx>> Subst<'tcx> for ty::EarlyBinder<T> {
-    type Inner = T;
+impl<T> EarlyBinder<Option<T>> {
+    pub fn transpose(self) -> Option<EarlyBinder<T>> {
+        self.0.map(|v| EarlyBinder(v))
+    }
+}
 
-    fn subst(self, tcx: TyCtxt<'tcx>, substs: &[GenericArg<'tcx>]) -> Self::Inner {
+impl<T, U> EarlyBinder<(T, U)> {
+    pub fn transpose_tuple2(self) -> (EarlyBinder<T>, EarlyBinder<U>) {
+        (EarlyBinder(self.0.0), EarlyBinder(self.0.1))
+    }
+}
+
+pub struct EarlyBinderIter<T> {
+    t: T,
+}
+
+impl<T: IntoIterator> EarlyBinder<T> {
+    pub fn transpose_iter(self) -> EarlyBinderIter<T::IntoIter> {
+        EarlyBinderIter { t: self.0.into_iter() }
+    }
+}
+
+impl<T: Iterator> Iterator for EarlyBinderIter<T> {
+    type Item = EarlyBinder<T::Item>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.t.next().map(|i| EarlyBinder(i))
+    }
+}
+
+impl<'tcx, T: TypeFoldable<'tcx>> ty::EarlyBinder<T> {
+    pub fn subst(self, tcx: TyCtxt<'tcx>, substs: &[GenericArg<'tcx>]) -> T {
         let mut folder = SubstFolder { tcx, substs, binders_passed: 0 };
         self.0.fold_with(&mut folder)
     }
diff --git a/compiler/rustc_middle/src/ty/trait_def.rs b/compiler/rustc_middle/src/ty/trait_def.rs
index 541dace5cc2b..ac79949fca5c 100644
--- a/compiler/rustc_middle/src/ty/trait_def.rs
+++ b/compiler/rustc_middle/src/ty/trait_def.rs
@@ -256,7 +256,6 @@ pub(super) fn trait_impls_of_provider(tcx: TyCtxt<'_>, trait_id: DefId) -> Trait
 }
 
 // Query provider for `incoherent_impls`.
-#[instrument(level = "debug", skip(tcx))]
 pub(super) fn incoherent_impls_provider(tcx: TyCtxt<'_>, simp: SimplifiedType) -> &[DefId] {
     let mut impls = Vec::new();
 
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
index 591bb7831b5b..d93aab04e992 100644
--- a/compiler/rustc_middle/src/ty/util.rs
+++ b/compiler/rustc_middle/src/ty/util.rs
@@ -3,11 +3,11 @@
 use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use crate::ty::layout::IntegerExt;
 use crate::ty::query::TyCtxtAt;
-use crate::ty::subst::{GenericArgKind, Subst, SubstsRef};
 use crate::ty::{
     self, DefIdTree, FallibleTypeFolder, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
     TypeVisitable,
 };
+use crate::ty::{GenericArgKind, SubstsRef};
 use rustc_apfloat::Float as _;
 use rustc_ast as ast;
 use rustc_attr::{self as attr, SignedInt, UnsignedInt};
@@ -627,7 +627,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     /// Expands the given impl trait type, stopping if the type is recursive.
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "debug", ret)]
     pub fn try_expand_impl_trait_type(
         self,
         def_id: DefId,
@@ -644,7 +644,6 @@ impl<'tcx> TyCtxt<'tcx> {
         };
 
         let expanded_type = visitor.expand_opaque_ty(def_id, substs).unwrap();
-        trace!(?expanded_type);
         if visitor.found_recursion { Err(expanded_type) } else { Ok(expanded_type) }
     }
 
@@ -652,6 +651,13 @@ impl<'tcx> TyCtxt<'tcx> {
         ty::EarlyBinder(self.type_of(def_id))
     }
 
+    pub fn bound_trait_impl_trait_tys(
+        self,
+        def_id: DefId,
+    ) -> ty::EarlyBinder<Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed>> {
+        ty::EarlyBinder(self.collect_trait_impl_trait_tys(def_id))
+    }
+
     pub fn bound_fn_sig(self, def_id: DefId) -> ty::EarlyBinder<ty::PolyFnSig<'tcx>> {
         ty::EarlyBinder(self.fn_sig(def_id))
     }
diff --git a/compiler/rustc_middle/src/ty/visit.rs b/compiler/rustc_middle/src/ty/visit.rs
index 5365067209af..9c3b6a794e19 100644
--- a/compiler/rustc_middle/src/ty/visit.rs
+++ b/compiler/rustc_middle/src/ty/visit.rs
@@ -84,7 +84,7 @@ pub trait TypeVisitable<'tcx>: fmt::Debug + Clone {
         self.has_vars_bound_at_or_above(ty::INNERMOST)
     }
 
-    #[instrument(level = "trace")]
+    #[instrument(level = "trace", ret)]
     fn has_type_flags(&self, flags: TypeFlags) -> bool {
         self.visit_with(&mut HasTypeFlagsVisitor { flags }).break_value() == Some(FoundFlags)
     }
@@ -199,7 +199,17 @@ pub trait TypeVisitor<'tcx>: Sized {
         c.super_visit_with(self)
     }
 
-    fn visit_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty_unevaluated(
+        &mut self,
+        uv: ty::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
+        uv.super_visit_with(self)
+    }
+
+    fn visit_mir_unevaluated(
+        &mut self,
+        uv: mir::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
         uv.super_visit_with(self)
     }
 
@@ -560,7 +570,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
     type BreakTy = FoundFlags;
 
     #[inline]
-    #[instrument(skip(self), level = "trace")]
+    #[instrument(skip(self), level = "trace", ret)]
     fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
         let flags = t.flags();
         trace!(t.flags=?t.flags());
@@ -572,7 +582,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
     }
 
     #[inline]
-    #[instrument(skip(self), level = "trace")]
+    #[instrument(skip(self), level = "trace", ret)]
     fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
         let flags = r.type_flags();
         trace!(r.flags=?flags);
@@ -584,7 +594,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
     }
 
     #[inline]
-    #[instrument(level = "trace")]
+    #[instrument(level = "trace", ret)]
     fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
         let flags = FlagComputation::for_const(c);
         trace!(r.flags=?flags);
@@ -596,8 +606,11 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
     }
 
     #[inline]
-    #[instrument(level = "trace")]
-    fn visit_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ControlFlow<Self::BreakTy> {
+    #[instrument(level = "trace", ret)]
+    fn visit_ty_unevaluated(
+        &mut self,
+        uv: ty::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
         let flags = FlagComputation::for_unevaluated_const(uv);
         trace!(r.flags=?flags);
         if flags.intersects(self.flags) {
@@ -607,8 +620,21 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
         }
     }
 
+    fn visit_mir_unevaluated(
+        &mut self,
+        uv: mir::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
+        let flags = FlagComputation::for_unevaluated_const(uv.shrink());
+        trace!(r.flags=?flags);
+        if flags.intersects(self.flags) {
+            ControlFlow::Break(FoundFlags)
+        } else {
+            ControlFlow::CONTINUE
+        }
+    }
+
     #[inline]
-    #[instrument(level = "trace")]
+    #[instrument(level = "trace", ret)]
     fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> ControlFlow<Self::BreakTy> {
         debug!(
             "HasTypeFlagsVisitor: predicate={:?} predicate.flags={:?} self.flags={:?}",
@@ -666,7 +692,7 @@ impl<'tcx> TypeVisitor<'tcx> for LateBoundRegionsCollector {
         // ignore the inputs to a projection, as they may not appear
         // in the normalized form
         if self.just_constrained {
-            if let ty::Projection(..) = t.kind() {
+            if let ty::Projection(..) | ty::Opaque(..) = t.kind() {
                 return ControlFlow::CONTINUE;
             }
         }
diff --git a/compiler/rustc_middle/src/ty/walk.rs b/compiler/rustc_middle/src/ty/walk.rs
index 02fe1f3a7bde..a3e11bbf056b 100644
--- a/compiler/rustc_middle/src/ty/walk.rs
+++ b/compiler/rustc_middle/src/ty/walk.rs
@@ -152,7 +152,7 @@ fn push_inner<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent: GenericArg<'tcx>)
             ty::Projection(data) => {
                 stack.extend(data.substs.iter().rev());
             }
-            ty::Dynamic(obj, lt) => {
+            ty::Dynamic(obj, lt, _) => {
                 stack.push(lt.into());
                 stack.extend(obj.iter().rev().flat_map(|predicate| {
                     let (substs, opt_ty) = match predicate.skip_binder() {
@@ -165,9 +165,9 @@ fn push_inner<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent: GenericArg<'tcx>)
                         }
                     };
 
-                    substs.iter().rev().chain(opt_ty.map(|term| match term {
-                        ty::Term::Ty(ty) => ty.into(),
-                        ty::Term::Const(ct) => ct.into(),
+                    substs.iter().rev().chain(opt_ty.map(|term| match term.unpack() {
+                        ty::TermKind::Ty(ty) => ty.into(),
+                        ty::TermKind::Const(ct) => ct.into(),
                     }))
                 }));
             }
diff --git a/compiler/rustc_query_impl/src/values.rs b/compiler/rustc_middle/src/values.rs
similarity index 65%
rename from compiler/rustc_query_impl/src/values.rs
rename to compiler/rustc_middle/src/values.rs
index 0ed48f8d4a05..7fbe9ae2a841 100644
--- a/compiler/rustc_query_impl/src/values.rs
+++ b/compiler/rustc_middle/src/values.rs
@@ -1,39 +1,28 @@
-use super::QueryCtxt;
-use rustc_middle::ty::{self, AdtSizedConstraint, Ty};
+use rustc_middle::ty::{self, AdtSizedConstraint, Ty, TyCtxt};
+use rustc_query_system::Value;
 
-pub(super) trait Value<'tcx>: Sized {
-    fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self;
-}
-
-impl<'tcx, T> Value<'tcx> for T {
-    default fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> T {
-        tcx.sess.abort_if_errors();
-        bug!("Value::from_cycle_error called without errors");
-    }
-}
-
-impl<'tcx> Value<'tcx> for Ty<'_> {
-    fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
+impl<'tcx> Value<TyCtxt<'tcx>> for Ty<'_> {
+    fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
         // SAFETY: This is never called when `Self` is not `Ty<'tcx>`.
         // FIXME: Represent the above fact in the trait system somehow.
         unsafe { std::mem::transmute::<Ty<'tcx>, Ty<'_>>(tcx.ty_error()) }
     }
 }
 
-impl<'tcx> Value<'tcx> for ty::SymbolName<'_> {
-    fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
+impl<'tcx> Value<TyCtxt<'tcx>> for ty::SymbolName<'_> {
+    fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
         // SAFETY: This is never called when `Self` is not `SymbolName<'tcx>`.
         // FIXME: Represent the above fact in the trait system somehow.
         unsafe {
             std::mem::transmute::<ty::SymbolName<'tcx>, ty::SymbolName<'_>>(ty::SymbolName::new(
-                *tcx, "<error>",
+                tcx, "<error>",
             ))
         }
     }
 }
 
-impl<'tcx> Value<'tcx> for AdtSizedConstraint<'_> {
-    fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
+impl<'tcx> Value<TyCtxt<'tcx>> for AdtSizedConstraint<'_> {
+    fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
         // SAFETY: This is never called when `Self` is not `AdtSizedConstraint<'tcx>`.
         // FIXME: Represent the above fact in the trait system somehow.
         unsafe {
@@ -44,8 +33,8 @@ impl<'tcx> Value<'tcx> for AdtSizedConstraint<'_> {
     }
 }
 
-impl<'tcx> Value<'tcx> for ty::Binder<'_, ty::FnSig<'_>> {
-    fn from_cycle_error(tcx: QueryCtxt<'tcx>) -> Self {
+impl<'tcx> Value<TyCtxt<'tcx>> for ty::Binder<'_, ty::FnSig<'_>> {
+    fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
         let err = tcx.ty_error();
         // FIXME(compiler-errors): It would be nice if we could get the
         // query key, so we could at least generate a fn signature that
diff --git a/compiler/rustc_mir_build/src/build/block.rs b/compiler/rustc_mir_build/src/build/block.rs
index d5213dc0e046..fc1b301402b7 100644
--- a/compiler/rustc_mir_build/src/build/block.rs
+++ b/compiler/rustc_mir_build/src/build/block.rs
@@ -109,15 +109,183 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         )
                     );
                 }
+                StmtKind::Let {
+                    remainder_scope,
+                    init_scope,
+                    pattern,
+                    initializer: Some(initializer),
+                    lint_level,
+                    else_block: Some(else_block),
+                } => {
+                    // When lowering the statement `let <pat> = <expr> else { <else> };`,
+                    // the `<else>` block is nested in the parent scope enclosing this statment.
+                    // That scope is usually either the enclosing block scope,
+                    // or the remainder scope of the last statement.
+                    // This is to make sure that temporaries instantiated in `<expr>` are dropped
+                    // as well.
+                    // In addition, even though bindings in `<pat>` only come into scope if
+                    // the pattern matching passes, in the MIR building the storages for them
+                    // are declared as live any way.
+                    // This is similar to `let x;` statements without an initializer expression,
+                    // where the value of `x` in this example may or may be assigned,
+                    // because the storage for their values may not be live after all due to
+                    // failure in pattern matching.
+                    // For this reason, we declare those storages as live but we do not schedule
+                    // any drop yet- they are scheduled later after the pattern matching.
+                    // The generated MIR will have `StorageDead` whenever the control flow breaks out
+                    // of the parent scope, regardless of the result of the pattern matching.
+                    // However, the drops are inserted in MIR only when the control flow breaks out of
+                    // the scope of the remainder scope associated with this `let .. else` statement.
+                    // Pictorial explanation of the scope structure:
+                    // ┌─────────────────────────────────┐
+                    // │  Scope of the enclosing block,  │
+                    // │  or the last remainder scope    │
+                    // │  ┌───────────────────────────┐  │
+                    // │  │  Scope for <else> block   │  │
+                    // │  └───────────────────────────┘  │
+                    // │  ┌───────────────────────────┐  │
+                    // │  │  Remainder scope of       │  │
+                    // │  │  this let-else statement  │  │
+                    // │  │  ┌─────────────────────┐  │  │
+                    // │  │  │ <expr> scope        │  │  │
+                    // │  │  └─────────────────────┘  │  │
+                    // │  │  extended temporaries in  │  │
+                    // │  │  <expr> lives in this     │  │
+                    // │  │  scope                    │  │
+                    // │  │  ┌─────────────────────┐  │  │
+                    // │  │  │ Scopes for the rest │  │  │
+                    // │  │  └─────────────────────┘  │  │
+                    // │  └───────────────────────────┘  │
+                    // └─────────────────────────────────┘
+                    // Generated control flow:
+                    //          │ let Some(x) = y() else { return; }
+                    //          │
+                    // ┌────────▼───────┐
+                    // │ evaluate y()   │
+                    // └────────┬───────┘
+                    //          │              ┌────────────────┐
+                    // ┌────────▼───────┐      │Drop temporaries│
+                    // │Test the pattern├──────►in y()          │
+                    // └────────┬───────┘      │because breaking│
+                    //          │              │out of <expr>   │
+                    // ┌────────▼───────┐      │scope           │
+                    // │Move value into │      └───────┬────────┘
+                    // │binding x       │              │
+                    // └────────┬───────┘      ┌───────▼────────┐
+                    //          │              │Drop extended   │
+                    // ┌────────▼───────┐      │temporaries in  │
+                    // │Drop temporaries│      │<expr> because  │
+                    // │in y()          │      │breaking out of │
+                    // │because breaking│      │remainder scope │
+                    // │out of <expr>   │      └───────┬────────┘
+                    // │scope           │              │
+                    // └────────┬───────┘      ┌───────▼────────┐
+                    //          │              │Enter <else>    ├────────►
+                    // ┌────────▼───────┐      │block           │ return;
+                    // │Continue...     │      └────────────────┘
+                    // └────────────────┘
+
+                    let ignores_expr_result = matches!(pattern.kind, PatKind::Wild);
+                    this.block_context.push(BlockFrame::Statement { ignores_expr_result });
+
+                    // Lower the `else` block first because its parent scope is actually
+                    // enclosing the rest of the `let .. else ..` parts.
+                    let else_block_span = this.thir[*else_block].span;
+                    // This place is not really used because this destination place
+                    // should never be used to take values at the end of the failure
+                    // block.
+                    let dummy_place = this.temp(this.tcx.types.never, else_block_span);
+                    let failure_entry = this.cfg.start_new_block();
+                    let failure_block;
+                    unpack!(
+                        failure_block = this.ast_block(
+                            dummy_place,
+                            failure_entry,
+                            *else_block,
+                            this.source_info(else_block_span),
+                        )
+                    );
+                    this.cfg.terminate(
+                        failure_block,
+                        this.source_info(else_block_span),
+                        TerminatorKind::Unreachable,
+                    );
+
+                    // Declare the bindings, which may create a source scope.
+                    let remainder_span = remainder_scope.span(this.tcx, this.region_scope_tree);
+                    this.push_scope((*remainder_scope, source_info));
+                    let_scope_stack.push(remainder_scope);
+
+                    let visibility_scope =
+                        Some(this.new_source_scope(remainder_span, LintLevel::Inherited, None));
+
+                    let init = &this.thir[*initializer];
+                    let initializer_span = init.span;
+                    let failure = unpack!(
+                        block = this.in_opt_scope(
+                            opt_destruction_scope.map(|de| (de, source_info)),
+                            |this| {
+                                let scope = (*init_scope, source_info);
+                                this.in_scope(scope, *lint_level, |this| {
+                                    this.declare_bindings(
+                                        visibility_scope,
+                                        remainder_span,
+                                        pattern,
+                                        ArmHasGuard(false),
+                                        Some((None, initializer_span)),
+                                    );
+                                    this.visit_primary_bindings(
+                                        pattern,
+                                        UserTypeProjections::none(),
+                                        &mut |this, _, _, _, node, span, _, _| {
+                                            this.storage_live_binding(
+                                                block,
+                                                node,
+                                                span,
+                                                OutsideGuard,
+                                                true,
+                                            );
+                                            this.schedule_drop_for_binding(
+                                                node,
+                                                span,
+                                                OutsideGuard,
+                                            );
+                                        },
+                                    );
+                                    this.ast_let_else(
+                                        block,
+                                        init,
+                                        initializer_span,
+                                        *else_block,
+                                        &last_remainder_scope,
+                                        pattern,
+                                    )
+                                })
+                            }
+                        )
+                    );
+                    this.cfg.goto(failure, source_info, failure_entry);
+
+                    if let Some(source_scope) = visibility_scope {
+                        this.source_scope = source_scope;
+                    }
+                    last_remainder_scope = *remainder_scope;
+                }
+                StmtKind::Let { init_scope, initializer: None, else_block: Some(_), .. } => {
+                    span_bug!(
+                        init_scope.span(this.tcx, this.region_scope_tree),
+                        "initializer is missing, but else block is present in this let binding",
+                    )
+                }
                 StmtKind::Let {
                     remainder_scope,
                     init_scope,
                     ref pattern,
                     initializer,
                     lint_level,
-                    else_block,
+                    else_block: None,
                 } => {
-                    let ignores_expr_result = matches!(*pattern.kind, PatKind::Wild);
+                    let ignores_expr_result = matches!(pattern.kind, PatKind::Wild);
                     this.block_context.push(BlockFrame::Statement { ignores_expr_result });
 
                     // Enter the remainder scope, i.e., the bindings' destruction scope.
@@ -141,27 +309,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                 |this| {
                                     let scope = (*init_scope, source_info);
                                     this.in_scope(scope, *lint_level, |this| {
-                                        if let Some(else_block) = else_block {
-                                            this.ast_let_else(
-                                                block,
-                                                init,
-                                                initializer_span,
-                                                *else_block,
-                                                visibility_scope,
-                                                last_remainder_scope,
-                                                remainder_span,
-                                                pattern,
-                                            )
-                                        } else {
-                                            this.declare_bindings(
-                                                visibility_scope,
-                                                remainder_span,
-                                                pattern,
-                                                ArmHasGuard(false),
-                                                Some((None, initializer_span)),
-                                            );
-                                            this.expr_into_pattern(block, pattern.clone(), init) // irrefutable pattern
-                                        }
+                                        this.declare_bindings(
+                                            visibility_scope,
+                                            remainder_span,
+                                            pattern,
+                                            ArmHasGuard(false),
+                                            Some((None, initializer_span)),
+                                        );
+                                        this.expr_into_pattern(block, &pattern, init)
+                                        // irrefutable pattern
                                     })
                                 },
                             )
diff --git a/compiler/rustc_mir_build/src/build/expr/as_constant.rs b/compiler/rustc_mir_build/src/build/expr/as_constant.rs
index b316a6eeac1c..37dc1ad9f0d4 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_constant.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_constant.rs
@@ -2,26 +2,19 @@
 
 use crate::build::{parse_float_into_constval, Builder};
 use rustc_ast as ast;
-use rustc_hir::def_id::DefId;
+use rustc_middle::mir;
 use rustc_middle::mir::interpret::{
     Allocation, ConstValue, LitToConstError, LitToConstInput, Scalar,
 };
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
-use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty, TyCtxt};
+use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, TyCtxt};
 use rustc_target::abi::Size;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// Compile `expr`, yielding a compile-time constant. Assumes that
     /// `expr` is a valid compile-time constant!
     pub(crate) fn as_constant(&mut self, expr: &Expr<'tcx>) -> Constant<'tcx> {
-        let create_uneval_from_def_id =
-            |tcx: TyCtxt<'tcx>, def_id: DefId, ty: Ty<'tcx>, substs: SubstsRef<'tcx>| {
-                let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
-                tcx.mk_const(ty::ConstS { kind: ty::ConstKind::Unevaluated(uneval), ty })
-            };
-
         let this = self;
         let tcx = this.tcx;
         let Expr { ty, temp_lifetime: _, span, ref kind } = *expr;
@@ -42,10 +35,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Constant { span, user_ty: None, literal }
             }
             ExprKind::NonHirLiteral { lit, ref user_ty } => {
-                let user_ty = user_ty.as_ref().map(|box user_ty| {
+                let user_ty = user_ty.as_ref().map(|user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span,
-                        user_ty: *user_ty,
+                        user_ty: user_ty.clone(),
                         inferred_ty: ty,
                     })
                 });
@@ -54,10 +47,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Constant { span, user_ty: user_ty, literal }
             }
             ExprKind::ZstLiteral { ref user_ty } => {
-                let user_ty = user_ty.as_ref().map(|box user_ty| {
+                let user_ty = user_ty.as_ref().map(|user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span,
-                        user_ty: *user_ty,
+                        user_ty: user_ty.clone(),
                         inferred_ty: ty,
                     })
                 });
@@ -66,14 +59,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Constant { span, user_ty: user_ty, literal }
             }
             ExprKind::NamedConst { def_id, substs, ref user_ty } => {
-                let user_ty = user_ty.as_ref().map(|box user_ty| {
+                let user_ty = user_ty.as_ref().map(|user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span,
-                        user_ty: *user_ty,
+                        user_ty: user_ty.clone(),
                         inferred_ty: ty,
                     })
                 });
-                let literal = ConstantKind::Ty(create_uneval_from_def_id(tcx, def_id, ty, substs));
+
+                let uneval =
+                    mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
+                let literal = ConstantKind::Unevaluated(uneval, ty);
 
                 Constant { user_ty, span, literal }
             }
@@ -85,7 +81,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Constant { user_ty: None, span, literal }
             }
             ExprKind::ConstBlock { did: def_id, substs } => {
-                let literal = ConstantKind::Ty(create_uneval_from_def_id(tcx, def_id, ty, substs));
+                let uneval =
+                    mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
+                let literal = ConstantKind::Unevaluated(uneval, ty);
 
                 Constant { user_ty: None, span, literal }
             }
diff --git a/compiler/rustc_mir_build/src/build/expr/as_place.rs b/compiler/rustc_mir_build/src/build/expr/as_place.rs
index b8277f28cdc4..4d9e9b7c4738 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_place.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_place.rs
@@ -2,7 +2,7 @@
 
 use crate::build::expr::category::Category;
 use crate::build::ForGuard::{OutsideGuard, RefWithinGuard};
-use crate::build::{BlockAnd, BlockAndExtension, Builder};
+use crate::build::{BlockAnd, BlockAndExtension, Builder, Capture, CaptureMap};
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::hir::place::Projection as HirProjection;
 use rustc_middle::hir::place::ProjectionKind as HirProjectionKind;
@@ -59,8 +59,6 @@ pub(crate) enum PlaceBase {
         var_hir_id: LocalVarId,
         /// DefId of the closure
         closure_def_id: LocalDefId,
-        /// The trait closure implements, `Fn`, `FnMut`, `FnOnce`
-        closure_kind: ty::ClosureKind,
     },
 }
 
@@ -71,7 +69,7 @@ pub(crate) enum PlaceBase {
 /// This is used internally when building a place for an expression like `a.b.c`. The fields `b`
 /// and `c` can be progressively pushed onto the place builder that is created when converting `a`.
 #[derive(Clone, Debug, PartialEq)]
-pub(crate) struct PlaceBuilder<'tcx> {
+pub(in crate::build) struct PlaceBuilder<'tcx> {
     base: PlaceBase,
     projection: Vec<PlaceElem<'tcx>>,
 }
@@ -104,6 +102,8 @@ fn convert_to_hir_projections_and_truncate_for_capture<'tcx>(
                 variant = Some(*idx);
                 continue;
             }
+            // These do not affect anything, they just make sure we know the right type.
+            ProjectionElem::OpaqueCast(_) => continue,
             ProjectionElem::Index(..)
             | ProjectionElem::ConstantIndex { .. }
             | ProjectionElem::Subslice { .. } => {
@@ -145,27 +145,6 @@ fn is_ancestor_or_same_capture(
     iter::zip(proj_possible_ancestor, proj_capture).all(|(a, b)| a == b)
 }
 
-/// Computes the index of a capture within the desugared closure provided the closure's
-/// `closure_min_captures` and the capture's index of the capture in the
-/// `ty::MinCaptureList` of the root variable `var_hir_id`.
-fn compute_capture_idx<'tcx>(
-    closure_min_captures: &ty::RootVariableMinCaptureList<'tcx>,
-    var_hir_id: LocalVarId,
-    root_var_idx: usize,
-) -> usize {
-    let mut res = 0;
-    for (var_id, capture_list) in closure_min_captures {
-        if *var_id == var_hir_id.0 {
-            res += root_var_idx;
-            break;
-        } else {
-            res += capture_list.len();
-        }
-    }
-
-    res
-}
-
 /// Given a closure, returns the index of a capture within the desugared closure struct and the
 /// `ty::CapturedPlace` which is the ancestor of the Place represented using the `var_hir_id`
 /// and `projection`.
@@ -174,58 +153,39 @@ fn compute_capture_idx<'tcx>(
 ///
 /// Returns None, when the ancestor is not found.
 fn find_capture_matching_projections<'a, 'tcx>(
-    typeck_results: &'a ty::TypeckResults<'tcx>,
+    upvars: &'a CaptureMap<'tcx>,
     var_hir_id: LocalVarId,
-    closure_def_id: LocalDefId,
     projections: &[PlaceElem<'tcx>],
-) -> Option<(usize, &'a ty::CapturedPlace<'tcx>)> {
-    let closure_min_captures = typeck_results.closure_min_captures.get(&closure_def_id)?;
-    let root_variable_min_captures = closure_min_captures.get(&var_hir_id.0)?;
-
+) -> Option<(usize, &'a Capture<'tcx>)> {
     let hir_projections = convert_to_hir_projections_and_truncate_for_capture(projections);
 
-    // If an ancestor is found, `idx` is the index within the list of captured places
-    // for root variable `var_hir_id` and `capture` is the `ty::CapturedPlace` itself.
-    let (idx, capture) = root_variable_min_captures.iter().enumerate().find(|(_, capture)| {
+    upvars.get_by_key_enumerated(var_hir_id.0).find(|(_, capture)| {
         let possible_ancestor_proj_kinds: Vec<_> =
-            capture.place.projections.iter().map(|proj| proj.kind).collect();
+            capture.captured_place.place.projections.iter().map(|proj| proj.kind).collect();
         is_ancestor_or_same_capture(&possible_ancestor_proj_kinds, &hir_projections)
-    })?;
-
-    // Convert index to be from the perspective of the entire closure_min_captures map
-    // instead of just the root variable capture list
-    Some((compute_capture_idx(closure_min_captures, var_hir_id, idx), capture))
+    })
 }
 
 /// Takes a PlaceBuilder and resolves the upvar (if any) within it, so that the
 /// `PlaceBuilder` now starts from `PlaceBase::Local`.
 ///
 /// Returns a Result with the error being the PlaceBuilder (`from_builder`) that was not found.
-fn to_upvars_resolved_place_builder<'a, 'tcx>(
+#[instrument(level = "trace", skip(cx), ret)]
+fn to_upvars_resolved_place_builder<'tcx>(
     from_builder: PlaceBuilder<'tcx>,
-    tcx: TyCtxt<'tcx>,
-    typeck_results: &'a ty::TypeckResults<'tcx>,
+    cx: &Builder<'_, 'tcx>,
 ) -> Result<PlaceBuilder<'tcx>, PlaceBuilder<'tcx>> {
     match from_builder.base {
         PlaceBase::Local(_) => Ok(from_builder),
-        PlaceBase::Upvar { var_hir_id, closure_def_id, closure_kind } => {
-            let mut upvar_resolved_place_builder = PlaceBuilder::from(ty::CAPTURE_STRUCT_LOCAL);
-            match closure_kind {
-                ty::ClosureKind::Fn | ty::ClosureKind::FnMut => {
-                    upvar_resolved_place_builder = upvar_resolved_place_builder.deref();
-                }
-                ty::ClosureKind::FnOnce => {}
-            }
-
+        PlaceBase::Upvar { var_hir_id, closure_def_id } => {
             let Some((capture_index, capture)) =
                 find_capture_matching_projections(
-                    typeck_results,
+                    &cx.upvars,
                     var_hir_id,
-                    closure_def_id,
                     &from_builder.projection,
                 ) else {
-                let closure_span = tcx.def_span(closure_def_id);
-                if !enable_precise_capture(tcx, closure_span) {
+                let closure_span = cx.tcx.def_span(closure_def_id);
+                if !enable_precise_capture(cx.tcx, closure_span) {
                     bug!(
                         "No associated capture found for {:?}[{:#?}] even though \
                             capture_disjoint_fields isn't enabled",
@@ -241,39 +201,18 @@ fn to_upvars_resolved_place_builder<'a, 'tcx>(
                 return Err(from_builder);
             };
 
-            // We won't be building MIR if the closure wasn't local
-            let closure_hir_id = tcx.hir().local_def_id_to_hir_id(closure_def_id);
-            let closure_ty = typeck_results.node_type(closure_hir_id);
-
-            let substs = match closure_ty.kind() {
-                ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
-                ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
-                _ => bug!("Lowering capture for non-closure type {:?}", closure_ty),
-            };
-
             // Access the capture by accessing the field within the Closure struct.
-            //
-            // We must have inferred the capture types since we are building MIR, therefore
-            // it's safe to call `tuple_element_ty` and we can unwrap here because
-            // we know that the capture exists and is the `capture_index`-th capture.
-            let var_ty = substs.tupled_upvars_ty().tuple_fields()[capture_index];
+            let capture_info = &cx.upvars[capture_index];
 
-            upvar_resolved_place_builder =
-                upvar_resolved_place_builder.field(Field::new(capture_index), var_ty);
-
-            // If the variable is captured via ByRef(Immutable/Mutable) Borrow,
-            // we need to deref it
-            upvar_resolved_place_builder = match capture.info.capture_kind {
-                ty::UpvarCapture::ByRef(_) => upvar_resolved_place_builder.deref(),
-                ty::UpvarCapture::ByValue => upvar_resolved_place_builder,
-            };
+            let mut upvar_resolved_place_builder = PlaceBuilder::from(capture_info.use_place);
 
             // We used some of the projections to build the capture itself,
             // now we apply the remaining to the upvar resolved place.
+            trace!(?capture.captured_place, ?from_builder.projection);
             let remaining_projections = strip_prefix(
-                capture.place.base_ty,
+                capture.captured_place.place.base_ty,
                 from_builder.projection,
-                &capture.place.projections,
+                &capture.captured_place.place.projections,
             );
             upvar_resolved_place_builder.projection.extend(remaining_projections);
 
@@ -294,16 +233,21 @@ fn strip_prefix<'tcx>(
     prefix_projections: &[HirProjection<'tcx>],
 ) -> impl Iterator<Item = PlaceElem<'tcx>> {
     let mut iter = projections.into_iter();
+    let mut next = || match iter.next()? {
+        // Filter out opaque casts, they are unnecessary in the prefix.
+        ProjectionElem::OpaqueCast(..) => iter.next(),
+        other => Some(other),
+    };
     for projection in prefix_projections {
         match projection.kind {
             HirProjectionKind::Deref => {
-                assert!(matches!(iter.next(), Some(ProjectionElem::Deref)));
+                assert!(matches!(next(), Some(ProjectionElem::Deref)));
             }
             HirProjectionKind::Field(..) => {
                 if base_ty.is_enum() {
-                    assert!(matches!(iter.next(), Some(ProjectionElem::Downcast(..))));
+                    assert!(matches!(next(), Some(ProjectionElem::Downcast(..))));
                 }
-                assert!(matches!(iter.next(), Some(ProjectionElem::Field(..))));
+                assert!(matches!(next(), Some(ProjectionElem::Field(..))));
             }
             HirProjectionKind::Index | HirProjectionKind::Subslice => {
                 bug!("unexpected projection kind: {:?}", projection);
@@ -315,24 +259,16 @@ fn strip_prefix<'tcx>(
 }
 
 impl<'tcx> PlaceBuilder<'tcx> {
-    pub(crate) fn into_place<'a>(
-        self,
-        tcx: TyCtxt<'tcx>,
-        typeck_results: &'a ty::TypeckResults<'tcx>,
-    ) -> Place<'tcx> {
+    pub(in crate::build) fn into_place(self, cx: &Builder<'_, 'tcx>) -> Place<'tcx> {
         if let PlaceBase::Local(local) = self.base {
-            Place { local, projection: tcx.intern_place_elems(&self.projection) }
+            Place { local, projection: cx.tcx.intern_place_elems(&self.projection) }
         } else {
-            self.expect_upvars_resolved(tcx, typeck_results).into_place(tcx, typeck_results)
+            self.expect_upvars_resolved(cx).into_place(cx)
         }
     }
 
-    fn expect_upvars_resolved<'a>(
-        self,
-        tcx: TyCtxt<'tcx>,
-        typeck_results: &'a ty::TypeckResults<'tcx>,
-    ) -> PlaceBuilder<'tcx> {
-        to_upvars_resolved_place_builder(self, tcx, typeck_results).unwrap()
+    fn expect_upvars_resolved(self, cx: &Builder<'_, 'tcx>) -> PlaceBuilder<'tcx> {
+        to_upvars_resolved_place_builder(self, cx).unwrap()
     }
 
     /// Attempts to resolve the `PlaceBuilder`.
@@ -346,18 +282,21 @@ impl<'tcx> PlaceBuilder<'tcx> {
     /// not captured. This can happen because the final mir that will be
     /// generated doesn't require a read for this place. Failures will only
     /// happen inside closures.
-    pub(crate) fn try_upvars_resolved<'a>(
+    pub(in crate::build) fn try_upvars_resolved(
         self,
-        tcx: TyCtxt<'tcx>,
-        typeck_results: &'a ty::TypeckResults<'tcx>,
+        cx: &Builder<'_, 'tcx>,
     ) -> Result<PlaceBuilder<'tcx>, PlaceBuilder<'tcx>> {
-        to_upvars_resolved_place_builder(self, tcx, typeck_results)
+        to_upvars_resolved_place_builder(self, cx)
     }
 
     pub(crate) fn base(&self) -> PlaceBase {
         self.base
     }
 
+    pub(crate) fn projection(&self) -> &[PlaceElem<'tcx>] {
+        &self.projection
+    }
+
     pub(crate) fn field(self, f: Field, ty: Ty<'tcx>) -> Self {
         self.project(PlaceElem::Field(f, ty))
     }
@@ -392,6 +331,12 @@ impl<'tcx> From<PlaceBase> for PlaceBuilder<'tcx> {
     }
 }
 
+impl<'tcx> From<Place<'tcx>> for PlaceBuilder<'tcx> {
+    fn from(p: Place<'tcx>) -> Self {
+        Self { base: PlaceBase::Local(p.local), projection: p.projection.to_vec() }
+    }
+}
+
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// Compile `expr`, yielding a place that we can move from etc.
     ///
@@ -411,7 +356,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         expr: &Expr<'tcx>,
     ) -> BlockAnd<Place<'tcx>> {
         let place_builder = unpack!(block = self.as_place_builder(block, expr));
-        block.and(place_builder.into_place(self.tcx, self.typeck_results))
+        block.and(place_builder.into_place(self))
     }
 
     /// This is used when constructing a compound `Place`, so that we can avoid creating
@@ -435,7 +380,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         expr: &Expr<'tcx>,
     ) -> BlockAnd<Place<'tcx>> {
         let place_builder = unpack!(block = self.as_read_only_place_builder(block, expr));
-        block.and(place_builder.into_place(self.tcx, self.typeck_results))
+        block.and(place_builder.into_place(self))
     }
 
     /// This is used when constructing a compound `Place`, so that we can avoid creating
@@ -522,15 +467,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         fake_borrow_temps,
                     )
                 );
-                if let Some(box user_ty) = user_ty {
+                if let Some(user_ty) = user_ty {
                     let annotation_index =
                         this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                             span: source_info.span,
-                            user_ty: *user_ty,
+                            user_ty: user_ty.clone(),
                             inferred_ty: expr.ty,
                         });
 
-                    let place = place_builder.clone().into_place(this.tcx, this.typeck_results);
+                    let place = place_builder.clone().into_place(this);
                     this.cfg.push(
                         block,
                         Statement {
@@ -551,11 +496,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let source = &this.thir[source];
                 let temp =
                     unpack!(block = this.as_temp(block, source.temp_lifetime, source, mutability));
-                if let Some(box user_ty) = user_ty {
+                if let Some(user_ty) = user_ty {
                     let annotation_index =
                         this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                             span: source_info.span,
-                            user_ty: *user_ty,
+                            user_ty: user_ty.clone(),
                             inferred_ty: expr.ty,
                         });
                     this.cfg.push(
@@ -629,17 +574,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         closure_def_id: LocalDefId,
         var_hir_id: LocalVarId,
     ) -> BlockAnd<PlaceBuilder<'tcx>> {
-        let closure_ty =
-            self.typeck_results.node_type(self.tcx.hir().local_def_id_to_hir_id(closure_def_id));
-
-        let closure_kind = if let ty::Closure(_, closure_substs) = closure_ty.kind() {
-            self.infcx.closure_kind(closure_substs).unwrap()
-        } else {
-            // Generators are considered FnOnce.
-            ty::ClosureKind::FnOnce
-        };
-
-        block.and(PlaceBuilder::from(PlaceBase::Upvar { var_hir_id, closure_def_id, closure_kind }))
+        block.and(PlaceBuilder::from(PlaceBase::Upvar { var_hir_id, closure_def_id }))
     }
 
     /// Lower an index expression
@@ -678,7 +613,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         if is_outermost_index {
             self.read_fake_borrows(block, fake_borrow_temps, source_info)
         } else {
-            base_place = base_place.expect_upvars_resolved(self.tcx, self.typeck_results);
+            base_place = base_place.expect_upvars_resolved(self);
             self.add_fake_borrows_of_base(
                 &base_place,
                 block,
@@ -706,12 +641,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let lt = self.temp(bool_ty, expr_span);
 
         // len = len(slice)
-        self.cfg.push_assign(
-            block,
-            source_info,
-            len,
-            Rvalue::Len(slice.into_place(self.tcx, self.typeck_results)),
-        );
+        self.cfg.push_assign(block, source_info, len, Rvalue::Len(slice.into_place(self)));
         // lt = idx < len
         self.cfg.push_assign(
             block,
@@ -791,6 +721,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     }
                     ProjectionElem::Field(..)
                     | ProjectionElem::Downcast(..)
+                    | ProjectionElem::OpaqueCast(..)
                     | ProjectionElem::ConstantIndex { .. }
                     | ProjectionElem::Subslice { .. } => (),
                 }
diff --git a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
index 4b232a1b5153..16295b1b19a1 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
@@ -216,6 +216,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 };
                 let from_ty = CastTy::from_ty(ty);
                 let cast_ty = CastTy::from_ty(expr.ty);
+                debug!("ExprKind::Cast from_ty={from_ty:?}, cast_ty={:?}/{cast_ty:?}", expr.ty,);
                 let cast_kind = match (from_ty, cast_ty) {
                     (Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Int(_))) => {
                         CastKind::PointerExposeAddress
@@ -223,6 +224,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     (Some(CastTy::Int(_)), Some(CastTy::Ptr(_))) => {
                         CastKind::PointerFromExposedAddress
                     }
+                    (_, Some(CastTy::DynStar)) => CastKind::DynStar,
                     (_, _) => CastKind::Misc,
                 };
                 block.and(Rvalue::Cast(cast_kind, source, expr.ty))
@@ -327,11 +329,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     let place_builder =
                         unpack!(block = this.as_place_builder(block, &this.thir[*thir_place]));
 
-                    if let Ok(place_builder_resolved) =
-                        place_builder.try_upvars_resolved(this.tcx, this.typeck_results)
-                    {
-                        let mir_place =
-                            place_builder_resolved.into_place(this.tcx, this.typeck_results);
+                    if let Ok(place_builder_resolved) = place_builder.try_upvars_resolved(this) {
+                        let mir_place = place_builder_resolved.into_place(this);
                         this.cfg.push_fake_read(
                             block,
                             this.source_info(this.tcx.hir().span(*hir_id)),
@@ -622,8 +621,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // by the parent itself. The mutability of the current capture
             // is same as that of the capture in the parent closure.
             PlaceBase::Upvar { .. } => {
-                let enclosing_upvars_resolved =
-                    arg_place_builder.clone().into_place(this.tcx, this.typeck_results);
+                let enclosing_upvars_resolved = arg_place_builder.clone().into_place(this);
 
                 match enclosing_upvars_resolved.as_ref() {
                     PlaceRef {
@@ -643,12 +641,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         );
                         // Not in a closure
                         debug_assert!(
-                            this.upvar_mutbls.len() > upvar_index.index(),
-                            "Unexpected capture place, upvar_mutbls={:#?}, upvar_index={:?}",
-                            this.upvar_mutbls,
+                            this.upvars.len() > upvar_index.index(),
+                            "Unexpected capture place, upvars={:#?}, upvar_index={:?}",
+                            this.upvars,
                             upvar_index
                         );
-                        this.upvar_mutbls[upvar_index.index()]
+                        this.upvars[upvar_index.index()].mutability
                     }
                     _ => bug!("Unexpected capture place"),
                 }
@@ -660,7 +658,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             Mutability::Mut => BorrowKind::Mut { allow_two_phase_borrow: false },
         };
 
-        let arg_place = arg_place_builder.into_place(this.tcx, this.typeck_results);
+        let arg_place = arg_place_builder.into_place(this);
 
         this.cfg.push_assign(
             block,
diff --git a/compiler/rustc_mir_build/src/build/expr/as_temp.rs b/compiler/rustc_mir_build/src/build/expr/as_temp.rs
index e5dafb820bf8..0ca4e3745199 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_temp.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_temp.rs
@@ -23,6 +23,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         ensure_sufficient_stack(|| self.as_temp_inner(block, temp_lifetime, expr, mutability))
     }
 
+    #[instrument(skip(self), level = "debug")]
     fn as_temp_inner(
         &mut self,
         mut block: BasicBlock,
@@ -30,10 +31,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         expr: &Expr<'tcx>,
         mutability: Mutability,
     ) -> BlockAnd<Local> {
-        debug!(
-            "as_temp(block={:?}, temp_lifetime={:?}, expr={:?}, mutability={:?})",
-            block, temp_lifetime, expr, mutability
-        );
         let this = self;
 
         let expr_span = expr.span;
diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs
index 48ec7a06724a..4b8c134b9d0a 100644
--- a/compiler/rustc_mir_build/src/build/expr/into.rs
+++ b/compiler/rustc_mir_build/src/build/expr/into.rs
@@ -15,14 +15,13 @@ use std::iter;
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// Compile `expr`, storing the result into `destination`, which
     /// is assumed to be uninitialized.
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn expr_into_dest(
         &mut self,
         destination: Place<'tcx>,
         mut block: BasicBlock,
         expr: &Expr<'tcx>,
     ) -> BlockAnd<()> {
-        debug!("expr_into_dest(destination={:?}, block={:?}, expr={:?})", destination, block, expr);
-
         // since we frequently have to reference `self` from within a
         // closure, where `self` would be shadowed, it's easier to
         // just use the name `this` uniformly
@@ -366,9 +365,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             None => {
                                 let place_builder = place_builder.clone();
                                 this.consume_by_copy_or_move(
-                                    place_builder
-                                        .field(n, *ty)
-                                        .into_place(this.tcx, this.typeck_results),
+                                    place_builder.field(n, *ty).into_place(this),
                                 )
                             }
                         })
@@ -378,10 +375,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 };
 
                 let inferred_ty = expr.ty;
-                let user_ty = user_ty.as_ref().map(|box user_ty| {
+                let user_ty = user_ty.as_ref().map(|user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span: source_info.span,
-                        user_ty: *user_ty,
+                        user_ty: user_ty.clone(),
                         inferred_ty,
                     })
                 });
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index 080dab030316..4fddc24301ab 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -155,7 +155,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     ///
     /// * From each pre-binding block to the next pre-binding block.
     /// * From each otherwise block to the next pre-binding block.
-    #[tracing::instrument(level = "debug", skip(self, arms))]
+    #[instrument(level = "debug", skip(self, arms))]
     pub(crate) fn match_expr(
         &mut self,
         destination: Place<'tcx>,
@@ -220,10 +220,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let cause_matched_place = FakeReadCause::ForMatchedPlace(None);
         let source_info = self.source_info(scrutinee_span);
 
-        if let Ok(scrutinee_builder) =
-            scrutinee_place_builder.clone().try_upvars_resolved(self.tcx, self.typeck_results)
-        {
-            let scrutinee_place = scrutinee_builder.into_place(self.tcx, self.typeck_results);
+        if let Ok(scrutinee_builder) = scrutinee_place_builder.clone().try_upvars_resolved(self) {
+            let scrutinee_place = scrutinee_builder.into_place(self);
             self.cfg.push_fake_read(block, source_info, cause_matched_place, scrutinee_place);
         }
 
@@ -246,7 +244,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             .map(|arm| {
                 let arm = &self.thir[arm];
                 let arm_has_guard = arm.guard.is_some();
-                let arm_candidate = Candidate::new(scrutinee.clone(), &arm.pattern, arm_has_guard);
+                let arm_candidate =
+                    Candidate::new(scrutinee.clone(), &arm.pattern, arm_has_guard, self);
                 (arm, arm_candidate)
             })
             .collect()
@@ -348,12 +347,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     // ```
                     let mut opt_scrutinee_place: Option<(Option<&Place<'tcx>>, Span)> = None;
                     let scrutinee_place: Place<'tcx>;
-                    if let Ok(scrutinee_builder) = scrutinee_place_builder
-                        .clone()
-                        .try_upvars_resolved(this.tcx, this.typeck_results)
+                    if let Ok(scrutinee_builder) =
+                        scrutinee_place_builder.clone().try_upvars_resolved(this)
                     {
-                        scrutinee_place =
-                            scrutinee_builder.into_place(this.tcx, this.typeck_results);
+                        scrutinee_place = scrutinee_builder.into_place(this);
                         opt_scrutinee_place = Some((Some(&scrutinee_place), scrutinee_span));
                     }
                     let scope = this.declare_bindings(
@@ -373,6 +370,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         Some(arm.span),
                         Some(arm.scope),
                         Some(match_scope),
+                        false,
                     );
 
                     if let Some(source_scope) = scope {
@@ -418,6 +416,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         arm_span: Option<Span>,
         arm_scope: Option<region::Scope>,
         match_scope: Option<region::Scope>,
+        storages_alive: bool,
     ) -> BasicBlock {
         if candidate.subcandidates.is_empty() {
             // Avoid generating another `BasicBlock` when we only have one
@@ -431,6 +430,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 arm_span,
                 match_scope,
                 true,
+                storages_alive,
             )
         } else {
             // It's helpful to avoid scheduling drops multiple times to save
@@ -468,6 +468,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         arm_span,
                         match_scope,
                         schedule_drops,
+                        storages_alive,
                     );
                     if arm_scope.is_none() {
                         schedule_drops = false;
@@ -490,10 +491,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     pub(super) fn expr_into_pattern(
         &mut self,
         mut block: BasicBlock,
-        irrefutable_pat: Pat<'tcx>,
+        irrefutable_pat: &Pat<'tcx>,
         initializer: &Expr<'tcx>,
     ) -> BlockAnd<()> {
-        match *irrefutable_pat.kind {
+        match irrefutable_pat.kind {
             // Optimize the case of `let x = ...` to write directly into `x`
             PatKind::Binding { mode: BindingMode::ByValue, var, subpattern: None, .. } => {
                 let place =
@@ -518,17 +519,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // broken.
             PatKind::AscribeUserType {
                 subpattern:
-                    Pat {
+                    box Pat {
                         kind:
-                            box PatKind::Binding {
-                                mode: BindingMode::ByValue,
-                                var,
-                                subpattern: None,
-                                ..
+                            PatKind::Binding {
+                                mode: BindingMode::ByValue, var, subpattern: None, ..
                             },
                         ..
                     },
-                ascription: thir::Ascription { annotation, variance: _ },
+                ascription: thir::Ascription { ref annotation, variance: _ },
             } => {
                 let place =
                     self.storage_live_binding(block, var, irrefutable_pat.span, OutsideGuard, true);
@@ -541,7 +539,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
                 let ty_source_info = self.source_info(annotation.span);
 
-                let base = self.canonical_user_type_annotations.push(annotation);
+                let base = self.canonical_user_type_annotations.push(annotation.clone());
                 self.cfg.push(
                     block,
                     Statement {
@@ -573,7 +571,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
             _ => {
                 let place_builder = unpack!(block = self.as_place_builder(block, initializer));
-                self.place_into_pattern(block, irrefutable_pat, place_builder, true)
+                self.place_into_pattern(block, &irrefutable_pat, place_builder, true)
             }
         }
     }
@@ -581,11 +579,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     pub(crate) fn place_into_pattern(
         &mut self,
         block: BasicBlock,
-        irrefutable_pat: Pat<'tcx>,
+        irrefutable_pat: &Pat<'tcx>,
         initializer: PlaceBuilder<'tcx>,
         set_match_place: bool,
     ) -> BlockAnd<()> {
-        let mut candidate = Candidate::new(initializer.clone(), &irrefutable_pat, false);
+        let mut candidate = Candidate::new(initializer.clone(), &irrefutable_pat, false, self);
         let fake_borrow_temps = self.lower_match_tree(
             block,
             irrefutable_pat.span,
@@ -602,12 +600,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             while let Some(next) = {
                 for binding in &candidate_ref.bindings {
                     let local = self.var_local_id(binding.var_id, OutsideGuard);
-
-                    let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
-                        VarBindingForm { opt_match_place: Some((ref mut match_place, _)), .. },
-                    )))) = self.local_decls[local].local_info else {
-                        bug!("Let binding to non-user variable.")
-                    };
                     // `try_upvars_resolved` may fail if it is unable to resolve the given
                     // `PlaceBuilder` inside a closure. In this case, we don't want to include
                     // a scrutinee place. `scrutinee_place_builder` will fail for destructured
@@ -622,10 +614,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     //    let (v1, v2) = foo;
                     // };
                     // ```
-                    if let Ok(match_pair_resolved) =
-                        initializer.clone().try_upvars_resolved(self.tcx, self.typeck_results)
-                    {
-                        let place = match_pair_resolved.into_place(self.tcx, self.typeck_results);
+                    if let Ok(match_pair_resolved) = initializer.clone().try_upvars_resolved(self) {
+                        let place = match_pair_resolved.into_place(self);
+
+                        let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
+                            VarBindingForm { opt_match_place: Some((ref mut match_place, _)), .. },
+                        )))) = self.local_decls[local].local_info else {
+                            bug!("Let binding to non-user variable.")
+                        };
                         *match_place = Some(place);
                     }
                 }
@@ -646,6 +642,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             None,
             None,
             None,
+            false,
         )
         .unit()
     }
@@ -654,6 +651,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// scope for the bindings in these patterns, if such a scope had to be
     /// created. NOTE: Declaring the bindings should always be done in their
     /// drop scope.
+    #[instrument(skip(self), level = "debug")]
     pub(crate) fn declare_bindings(
         &mut self,
         mut visibility_scope: Option<SourceScope>,
@@ -662,7 +660,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         has_guard: ArmHasGuard,
         opt_match_place: Option<(Option<&Place<'tcx>>, Span)>,
     ) -> Option<SourceScope> {
-        debug!("declare_bindings: pattern={:?}", pattern);
         self.visit_primary_bindings(
             &pattern,
             UserTypeProjections::none(),
@@ -702,9 +699,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let local_id = self.var_local_id(var, for_guard);
         let source_info = self.source_info(span);
         self.cfg.push(block, Statement { source_info, kind: StatementKind::StorageLive(local_id) });
-        // Altough there is almost always scope for given variable in corner cases
+        // Although there is almost always scope for given variable in corner cases
         // like #92893 we might get variable with no scope.
-        if let Some(region_scope) = self.region_scope_tree.var_scope(var.0.local_id) && schedule_drop{
+        if let Some(region_scope) = self.region_scope_tree.var_scope(var.0.local_id) && schedule_drop {
             self.schedule_drop(span, region_scope, local_id, DropKind::Storage);
         }
         Place::from(local_id)
@@ -744,7 +741,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             "visit_primary_bindings: pattern={:?} pattern_user_ty={:?}",
             pattern, pattern_user_ty
         );
-        match *pattern.kind {
+        match pattern.kind {
             PatKind::Binding {
                 mutability,
                 name,
@@ -767,7 +764,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             | PatKind::Slice { ref prefix, ref slice, ref suffix } => {
                 let from = u64::try_from(prefix.len()).unwrap();
                 let to = u64::try_from(suffix.len()).unwrap();
-                for subpattern in prefix {
+                for subpattern in prefix.iter() {
                     self.visit_primary_bindings(subpattern, pattern_user_ty.clone().index(), f);
                 }
                 for subpattern in slice {
@@ -777,7 +774,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         f,
                     );
                 }
-                for subpattern in suffix {
+                for subpattern in suffix.iter() {
                     self.visit_primary_bindings(subpattern, pattern_user_ty.clone().index(), f);
                 }
             }
@@ -830,7 +827,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // may not all be in the leftmost subpattern. For example in
                 // `let (x | y) = ...`, the primary binding of `y` occurs in
                 // the right subpattern
-                for subpattern in pats {
+                for subpattern in pats.iter() {
                     self.visit_primary_bindings(subpattern, pattern_user_ty.clone(), f);
                 }
             }
@@ -868,11 +865,16 @@ struct Candidate<'pat, 'tcx> {
 }
 
 impl<'tcx, 'pat> Candidate<'pat, 'tcx> {
-    fn new(place: PlaceBuilder<'tcx>, pattern: &'pat Pat<'tcx>, has_guard: bool) -> Self {
+    fn new(
+        place: PlaceBuilder<'tcx>,
+        pattern: &'pat Pat<'tcx>,
+        has_guard: bool,
+        cx: &Builder<'_, 'tcx>,
+    ) -> Self {
         Candidate {
             span: pattern.span,
             has_guard,
-            match_pairs: smallvec![MatchPair { place, pattern }],
+            match_pairs: smallvec![MatchPair::new(place, pattern, cx)],
             bindings: Vec::new(),
             ascriptions: Vec::new(),
             subcandidates: Vec::new(),
@@ -982,7 +984,7 @@ enum TestKind<'tcx> {
     },
 
     /// Test whether the value falls within an inclusive or exclusive range
-    Range(PatRange<'tcx>),
+    Range(Box<PatRange<'tcx>>),
 
     /// Test that the length of the slice is equal to `len`.
     Len { len: u64, op: BinOp },
@@ -1048,6 +1050,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// if `x.0` matches `false` (for the third arm). In the (impossible at
     /// runtime) case when `x.0` is now `true`, we branch to
     /// `otherwise_block`.
+    #[instrument(skip(self, fake_borrows), level = "debug")]
     fn match_candidates<'pat>(
         &mut self,
         span: Span,
@@ -1057,11 +1060,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         candidates: &mut [&mut Candidate<'pat, 'tcx>],
         fake_borrows: &mut Option<FxIndexSet<Place<'tcx>>>,
     ) {
-        debug!(
-            "matched_candidate(span={:?}, candidates={:?}, start_block={:?}, otherwise_block={:?})",
-            span, candidates, start_block, otherwise_block,
-        );
-
         // Start by simplifying candidates. Once this process is complete, all
         // the match pairs which remain require some form of test, whether it
         // be a switch or pattern comparison.
@@ -1330,7 +1328,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
         // All of the or-patterns have been sorted to the end, so if the first
         // pattern is an or-pattern we only have or-patterns.
-        match *first_candidate.match_pairs[0].pattern.kind {
+        match first_candidate.match_pairs[0].pattern.kind {
             PatKind::Or { .. } => (),
             _ => {
                 self.test_candidates(
@@ -1350,7 +1348,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
         let mut otherwise = None;
         for match_pair in match_pairs {
-            let PatKind::Or { ref pats } = &*match_pair.pattern.kind else {
+            let PatKind::Or { ref pats } = &match_pair.pattern.kind else {
                 bug!("Or-patterns should have been sorted to the end");
             };
             let or_span = match_pair.pattern.span;
@@ -1380,19 +1378,23 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         )
     }
 
+    #[instrument(
+        skip(self, otherwise, or_span, place, fake_borrows, candidate, pats),
+        level = "debug"
+    )]
     fn test_or_pattern<'pat>(
         &mut self,
         candidate: &mut Candidate<'pat, 'tcx>,
         otherwise: &mut Option<BasicBlock>,
-        pats: &'pat [Pat<'tcx>],
+        pats: &'pat [Box<Pat<'tcx>>],
         or_span: Span,
         place: PlaceBuilder<'tcx>,
         fake_borrows: &mut Option<FxIndexSet<Place<'tcx>>>,
     ) {
-        debug!("test_or_pattern:\ncandidate={:#?}\npats={:#?}", candidate, pats);
+        debug!("candidate={:#?}\npats={:#?}", candidate, pats);
         let mut or_candidates: Vec<_> = pats
             .iter()
-            .map(|pat| Candidate::new(place.clone(), pat, candidate.has_guard))
+            .map(|pat| Candidate::new(place.clone(), pat, candidate.has_guard, self))
             .collect();
         let mut or_candidate_refs: Vec<_> = or_candidates.iter_mut().collect();
         let otherwise = if candidate.otherwise_block.is_some() {
@@ -1605,9 +1607,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
         // Insert a Shallow borrow of any places that is switched on.
         if let Some(fb) = fake_borrows && let Ok(match_place_resolved) =
-            match_place.clone().try_upvars_resolved(self.tcx, self.typeck_results)
+            match_place.clone().try_upvars_resolved(self)
         {
-            let resolved_place = match_place_resolved.into_place(self.tcx, self.typeck_results);
+            let resolved_place = match_place_resolved.into_place(self);
             fb.insert(resolved_place);
         }
 
@@ -1634,9 +1636,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             candidates = rest;
         }
         // at least the first candidate ought to be tested
-        assert!(total_candidate_count > candidates.len());
-        debug!("test_candidates: tested_candidates: {}", total_candidate_count - candidates.len());
-        debug!("test_candidates: untested_candidates: {}", candidates.len());
+        assert!(
+            total_candidate_count > candidates.len(),
+            "{}, {:#?}",
+            total_candidate_count,
+            candidates
+        );
+        debug!("tested_candidates: {}", total_candidate_count - candidates.len());
+        debug!("untested_candidates: {}", candidates.len());
 
         // HACK(matthewjasper) This is a closure so that we can let the test
         // create its blocks before the rest of the match. This currently
@@ -1783,8 +1790,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let expr_span = expr.span;
         let expr_place_builder = unpack!(block = self.lower_scrutinee(block, expr, expr_span));
         let wildcard = Pat::wildcard_from_ty(pat.ty);
-        let mut guard_candidate = Candidate::new(expr_place_builder.clone(), &pat, false);
-        let mut otherwise_candidate = Candidate::new(expr_place_builder.clone(), &wildcard, false);
+        let mut guard_candidate = Candidate::new(expr_place_builder.clone(), &pat, false, self);
+        let mut otherwise_candidate =
+            Candidate::new(expr_place_builder.clone(), &wildcard, false, self);
         let fake_borrow_temps = self.lower_match_tree(
             block,
             pat.span,
@@ -1794,10 +1802,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         );
         let mut opt_expr_place: Option<(Option<&Place<'tcx>>, Span)> = None;
         let expr_place: Place<'tcx>;
-        if let Ok(expr_builder) =
-            expr_place_builder.try_upvars_resolved(self.tcx, self.typeck_results)
-        {
-            expr_place = expr_builder.into_place(self.tcx, self.typeck_results);
+        if let Ok(expr_builder) = expr_place_builder.try_upvars_resolved(self) {
+            expr_place = expr_builder.into_place(self);
             opt_expr_place = Some((Some(&expr_place), expr_span));
         }
         let otherwise_post_guard_block = otherwise_candidate.pre_binding_block.unwrap();
@@ -1820,6 +1826,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             None,
             None,
             None,
+            false,
         );
 
         post_guard_block.unit()
@@ -1843,6 +1850,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         arm_span: Option<Span>,
         match_scope: Option<region::Scope>,
         schedule_drops: bool,
+        storages_alive: bool,
     ) -> BasicBlock {
         debug!("bind_and_guard_matched_candidate(candidate={:?})", candidate);
 
@@ -2058,7 +2066,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 self.cfg.push_fake_read(post_guard_block, guard_end, cause, Place::from(local_id));
             }
             assert!(schedule_drops, "patterns with guards must schedule drops");
-            self.bind_matched_candidate_for_arm_body(post_guard_block, true, by_value_bindings);
+            self.bind_matched_candidate_for_arm_body(
+                post_guard_block,
+                true,
+                by_value_bindings,
+                storages_alive,
+            );
 
             post_guard_block
         } else {
@@ -2072,6 +2085,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     .iter()
                     .flat_map(|(bindings, _)| bindings)
                     .chain(&candidate.bindings),
+                storages_alive,
             );
             block
         }
@@ -2161,6 +2175,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         block: BasicBlock,
         schedule_drops: bool,
         bindings: impl IntoIterator<Item = &'b Binding<'tcx>>,
+        storages_alive: bool,
     ) where
         'tcx: 'b,
     {
@@ -2170,13 +2185,20 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // Assign each of the bindings. This may trigger moves out of the candidate.
         for binding in bindings {
             let source_info = self.source_info(binding.span);
-            let local = self.storage_live_binding(
-                block,
-                binding.var_id,
-                binding.span,
-                OutsideGuard,
-                schedule_drops,
-            );
+            let local = if storages_alive {
+                // Here storages are already alive, probably because this is a binding
+                // from let-else.
+                // We just need to schedule drop for the value.
+                self.var_local_id(binding.var_id, OutsideGuard).into()
+            } else {
+                self.storage_live_binding(
+                    block,
+                    binding.var_id,
+                    binding.span,
+                    OutsideGuard,
+                    schedule_drops,
+                )
+            };
             if schedule_drops {
                 self.schedule_drop_for_binding(binding.var_id, binding.span, OutsideGuard);
             }
@@ -2195,6 +2217,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// first local is a binding for occurrences of `var` in the guard, which
     /// will have type `&T`. The second local is a binding for occurrences of
     /// `var` in the arm body, which will have type `T`.
+    #[instrument(skip(self), level = "debug")]
     fn declare_binding(
         &mut self,
         source_info: SourceInfo,
@@ -2209,19 +2232,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
         pat_span: Span,
     ) {
-        debug!(
-            "declare_binding(var_id={:?}, name={:?}, mode={:?}, var_ty={:?}, \
-             visibility_scope={:?}, source_info={:?})",
-            var_id, name, mode, var_ty, visibility_scope, source_info
-        );
-
         let tcx = self.tcx;
         let debug_source_info = SourceInfo { span: source_info.span, scope: visibility_scope };
         let binding_mode = match mode {
             BindingMode::ByValue => ty::BindingMode::BindByValue(mutability),
             BindingMode::ByRef(_) => ty::BindingMode::BindByReference(mutability),
         };
-        debug!("declare_binding: user_ty={:?}", user_ty);
         let local = LocalDecl::<'tcx> {
             mutability,
             ty: var_ty,
@@ -2271,7 +2287,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         } else {
             LocalsForNode::One(for_arm_body)
         };
-        debug!("declare_binding: vars={:?}", locals);
+        debug!(?locals);
         self.var_indices.insert(var_id, locals);
     }
 
@@ -2281,24 +2297,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         init: &Expr<'tcx>,
         initializer_span: Span,
         else_block: BlockId,
-        visibility_scope: Option<SourceScope>,
-        remainder_scope: region::Scope,
-        remainder_span: Span,
+        let_else_scope: &region::Scope,
         pattern: &Pat<'tcx>,
-    ) -> BlockAnd<()> {
+    ) -> BlockAnd<BasicBlock> {
         let else_block_span = self.thir[else_block].span;
-        let (matching, failure) = self.in_if_then_scope(remainder_scope, |this| {
+        let (matching, failure) = self.in_if_then_scope(*let_else_scope, |this| {
             let scrutinee = unpack!(block = this.lower_scrutinee(block, init, initializer_span));
-            let pat = Pat { ty: init.ty, span: else_block_span, kind: Box::new(PatKind::Wild) };
-            let mut wildcard = Candidate::new(scrutinee.clone(), &pat, false);
-            this.declare_bindings(
-                visibility_scope,
-                remainder_span,
-                pattern,
-                ArmHasGuard(false),
-                Some((None, initializer_span)),
-            );
-            let mut candidate = Candidate::new(scrutinee.clone(), pattern, false);
+            let pat = Pat { ty: init.ty, span: else_block_span, kind: PatKind::Wild };
+            let mut wildcard = Candidate::new(scrutinee.clone(), &pat, false, this);
+            let mut candidate = Candidate::new(scrutinee.clone(), pattern, false, this);
             let fake_borrow_temps = this.lower_match_tree(
                 block,
                 initializer_span,
@@ -2316,6 +2323,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 None,
                 None,
                 None,
+                true,
             );
             // This block is for the failure case
             let failure = this.bind_pattern(
@@ -2327,29 +2335,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 None,
                 None,
                 None,
+                true,
             );
-            this.break_for_else(failure, remainder_scope, this.source_info(initializer_span));
+            this.break_for_else(failure, *let_else_scope, this.source_info(initializer_span));
             matching.unit()
         });
-
-        // This place is not really used because this destination place
-        // should never be used to take values at the end of the failure
-        // block.
-        let dummy_place = self.temp(self.tcx.types.never, else_block_span);
-        let failure_block;
-        unpack!(
-            failure_block = self.ast_block(
-                dummy_place,
-                failure,
-                else_block,
-                self.source_info(else_block_span),
-            )
-        );
-        self.cfg.terminate(
-            failure_block,
-            self.source_info(else_block_span),
-            TerminatorKind::Unreachable,
-        );
-        matching.unit()
+        matching.and(failure)
     }
 }
diff --git a/compiler/rustc_mir_build/src/build/matches/simplify.rs b/compiler/rustc_mir_build/src/build/matches/simplify.rs
index c6298904140c..828f32db3618 100644
--- a/compiler/rustc_mir_build/src/build/matches/simplify.rs
+++ b/compiler/rustc_mir_build/src/build/matches/simplify.rs
@@ -37,12 +37,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     ///
     /// only generates a single switch. If this happens this method returns
     /// `true`.
+    #[instrument(skip(self, candidate), level = "debug")]
     pub(super) fn simplify_candidate<'pat>(
         &mut self,
         candidate: &mut Candidate<'pat, 'tcx>,
     ) -> bool {
         // repeatedly simplify match pairs until fixed point is reached
-        debug!(?candidate, "simplify_candidate");
+        debug!("{candidate:#?}");
 
         // existing_bindings and new_bindings exists to keep the semantics in order.
         // Reversing the binding order for bindings after `@` changes the binding order in places
@@ -67,7 +68,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         loop {
             let match_pairs = mem::take(&mut candidate.match_pairs);
 
-            if let [MatchPair { pattern: Pat { kind: box PatKind::Or { pats }, .. }, place }] =
+            if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place }] =
                 &*match_pairs
             {
                 existing_bindings.extend_from_slice(&new_bindings);
@@ -113,7 +114,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // late as possible.
                 candidate
                     .match_pairs
-                    .sort_by_key(|pair| matches!(*pair.pattern.kind, PatKind::Or { .. }));
+                    .sort_by_key(|pair| matches!(pair.pattern.kind, PatKind::Or { .. }));
                 debug!(simplified = ?candidate, "simplify_candidate");
                 return false; // if we were not able to simplify any, done.
             }
@@ -127,11 +128,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         candidate: &Candidate<'pat, 'tcx>,
         place: PlaceBuilder<'tcx>,
-        pats: &'pat [Pat<'tcx>],
+        pats: &'pat [Box<Pat<'tcx>>],
     ) -> Vec<Candidate<'pat, 'tcx>> {
         pats.iter()
-            .map(|pat| {
-                let mut candidate = Candidate::new(place.clone(), pat, candidate.has_guard);
+            .map(|box pat| {
+                let mut candidate = Candidate::new(place.clone(), pat, candidate.has_guard, self);
                 self.simplify_candidate(&mut candidate);
                 candidate
             })
@@ -149,23 +150,21 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         candidate: &mut Candidate<'pat, 'tcx>,
     ) -> Result<(), MatchPair<'pat, 'tcx>> {
         let tcx = self.tcx;
-        match *match_pair.pattern.kind {
+        match match_pair.pattern.kind {
             PatKind::AscribeUserType {
                 ref subpattern,
                 ascription: thir::Ascription { ref annotation, variance },
             } => {
                 // Apply the type ascription to the value at `match_pair.place`, which is the
-                if let Ok(place_resolved) =
-                    match_pair.place.clone().try_upvars_resolved(self.tcx, self.typeck_results)
-                {
+                if let Ok(place_resolved) = match_pair.place.clone().try_upvars_resolved(self) {
                     candidate.ascriptions.push(Ascription {
                         annotation: annotation.clone(),
-                        source: place_resolved.into_place(self.tcx, self.typeck_results),
+                        source: place_resolved.into_place(self),
                         variance,
                     });
                 }
 
-                candidate.match_pairs.push(MatchPair::new(match_pair.place, subpattern));
+                candidate.match_pairs.push(MatchPair::new(match_pair.place, subpattern, self));
 
                 Ok(())
             }
@@ -184,12 +183,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 ref subpattern,
                 is_primary: _,
             } => {
-                if let Ok(place_resolved) =
-                    match_pair.place.clone().try_upvars_resolved(self.tcx, self.typeck_results)
-                {
+                if let Ok(place_resolved) = match_pair.place.clone().try_upvars_resolved(self) {
                     candidate.bindings.push(Binding {
                         span: match_pair.pattern.span,
-                        source: place_resolved.into_place(self.tcx, self.typeck_results),
+                        source: place_resolved.into_place(self),
                         var_id: var,
                         binding_mode: mode,
                     });
@@ -197,7 +194,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
                 if let Some(subpattern) = subpattern.as_ref() {
                     // this is the `x @ P` case; have to keep matching against `P` now
-                    candidate.match_pairs.push(MatchPair::new(match_pair.place, subpattern));
+                    candidate.match_pairs.push(MatchPair::new(match_pair.place, subpattern, self));
                 }
 
                 Ok(())
@@ -208,7 +205,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Err(match_pair)
             }
 
-            PatKind::Range(PatRange { lo, hi, end }) => {
+            PatKind::Range(box PatRange { lo, hi, end }) => {
                 let (range, bias) = match *lo.ty().kind() {
                     ty::Char => {
                         (Some(('\u{0000}' as u128, '\u{10FFFF}' as u128, Size::from_bits(32))), 0)
@@ -254,7 +251,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         &mut candidate.match_pairs,
                         &match_pair.place,
                         prefix,
-                        slice.as_ref(),
+                        slice,
                         suffix,
                     );
                     Ok(())
@@ -294,7 +291,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     &mut candidate.match_pairs,
                     &match_pair.place,
                     prefix,
-                    slice.as_ref(),
+                    slice,
                     suffix,
                 );
                 Ok(())
@@ -308,7 +305,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
             PatKind::Deref { ref subpattern } => {
                 let place_builder = match_pair.place.deref();
-                candidate.match_pairs.push(MatchPair::new(place_builder, subpattern));
+                candidate.match_pairs.push(MatchPair::new(place_builder, subpattern, self));
                 Ok(())
             }
 
diff --git a/compiler/rustc_mir_build/src/build/matches/test.rs b/compiler/rustc_mir_build/src/build/matches/test.rs
index 598da80c574a..b597ecfaa4d6 100644
--- a/compiler/rustc_mir_build/src/build/matches/test.rs
+++ b/compiler/rustc_mir_build/src/build/matches/test.rs
@@ -14,8 +14,8 @@ use rustc_hir::{LangItem, RangeEnd};
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
-use rustc_middle::ty::subst::{GenericArg, Subst};
 use rustc_middle::ty::util::IntTypeExt;
+use rustc_middle::ty::GenericArg;
 use rustc_middle::ty::{self, adjustment::PointerCast, Ty, TyCtxt};
 use rustc_span::def_id::DefId;
 use rustc_span::symbol::{sym, Symbol};
@@ -29,7 +29,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     ///
     /// It is a bug to call this with a not-fully-simplified pattern.
     pub(super) fn test<'pat>(&mut self, match_pair: &MatchPair<'pat, 'tcx>) -> Test<'tcx> {
-        match *match_pair.pattern.kind {
+        match match_pair.pattern.kind {
             PatKind::Variant { adt_def, substs: _, variant_index: _, subpatterns: _ } => Test {
                 span: match_pair.pattern.span,
                 kind: TestKind::Switch {
@@ -58,10 +58,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 kind: TestKind::Eq { value, ty: match_pair.pattern.ty },
             },
 
-            PatKind::Range(range) => {
+            PatKind::Range(ref range) => {
                 assert_eq!(range.lo.ty(), match_pair.pattern.ty);
                 assert_eq!(range.hi.ty(), match_pair.pattern.ty);
-                Test { span: match_pair.pattern.span, kind: TestKind::Range(range) }
+                Test { span: match_pair.pattern.span, kind: TestKind::Range(range.clone()) }
             }
 
             PatKind::Slice { ref prefix, ref slice, ref suffix } => {
@@ -92,7 +92,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             return false;
         };
 
-        match *match_pair.pattern.kind {
+        match match_pair.pattern.kind {
             PatKind::Constant { value } => {
                 options
                     .entry(value)
@@ -102,9 +102,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             PatKind::Variant { .. } => {
                 panic!("you should have called add_variants_to_switch instead!");
             }
-            PatKind::Range(range) => {
+            PatKind::Range(ref range) => {
                 // Check that none of the switch values are in the range.
-                self.values_not_contained_in_range(range, options).unwrap_or(false)
+                self.values_not_contained_in_range(&*range, options).unwrap_or(false)
             }
             PatKind::Slice { .. }
             | PatKind::Array { .. }
@@ -130,7 +130,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             return false;
         };
 
-        match *match_pair.pattern.kind {
+        match match_pair.pattern.kind {
             PatKind::Variant { adt_def: _, variant_index, .. } => {
                 // We have a pattern testing for variant `variant_index`
                 // set the corresponding index to true
@@ -144,6 +144,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         }
     }
 
+    #[instrument(skip(self, make_target_blocks, place_builder), level = "debug")]
     pub(super) fn perform_test(
         &mut self,
         match_start_span: Span,
@@ -153,21 +154,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         test: &Test<'tcx>,
         make_target_blocks: impl FnOnce(&mut Self) -> Vec<BasicBlock>,
     ) {
-        let place: Place<'tcx>;
-        if let Ok(test_place_builder) =
-            place_builder.try_upvars_resolved(self.tcx, self.typeck_results)
-        {
-            place = test_place_builder.into_place(self.tcx, self.typeck_results);
-        } else {
-            return;
-        }
-        debug!(
-            "perform_test({:?}, {:?}: {:?}, {:?})",
-            block,
-            place,
-            place.ty(&self.local_decls, self.tcx),
-            test
-        );
+        let place = place_builder.into_place(self);
+        let place_ty = place.ty(&self.local_decls, self.tcx);
+        debug!(?place, ?place_ty,);
 
         let source_info = self.source_info(test.span);
         match test.kind {
@@ -272,7 +261,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            TestKind::Range(PatRange { lo, hi, ref end }) => {
+            TestKind::Range(box PatRange { lo, hi, ref end }) => {
                 let lower_bound_success = self.cfg.start_new_block();
                 let target_blocks = make_target_blocks(self);
 
@@ -506,7 +495,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let (match_pair_index, match_pair) =
             candidate.match_pairs.iter().enumerate().find(|&(_, mp)| mp.place == *test_place)?;
 
-        match (&test.kind, &*match_pair.pattern.kind) {
+        match (&test.kind, &match_pair.pattern.kind) {
             // If we are performing a variant switch, then this
             // informs variant patterns, but nothing else.
             (
@@ -540,9 +529,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Some(index)
             }
 
-            (&TestKind::SwitchInt { switch_ty: _, ref options }, &PatKind::Range(range)) => {
+            (&TestKind::SwitchInt { switch_ty: _, ref options }, &PatKind::Range(ref range)) => {
                 let not_contained =
-                    self.values_not_contained_in_range(range, options).unwrap_or(false);
+                    self.values_not_contained_in_range(&*range, options).unwrap_or(false);
 
                 if not_contained {
                     // No switch values are contained in the pattern range,
@@ -569,7 +558,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             match_pair_index,
                             candidate,
                             prefix,
-                            slice.as_ref(),
+                            slice,
                             suffix,
                         );
                         Some(0)
@@ -607,7 +596,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             match_pair_index,
                             candidate,
                             prefix,
-                            slice.as_ref(),
+                            slice,
                             suffix,
                         );
                         Some(0)
@@ -631,7 +620,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            (&TestKind::Range(test), &PatKind::Range(pat)) => {
+            (&TestKind::Range(ref test), &PatKind::Range(ref pat)) => {
                 use std::cmp::Ordering::*;
 
                 if test == pat {
@@ -658,8 +647,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 no_overlap
             }
 
-            (&TestKind::Range(range), &PatKind::Constant { value }) => {
-                if let Some(false) = self.const_range_contains(range, value) {
+            (&TestKind::Range(ref range), &PatKind::Constant { value }) => {
+                if let Some(false) = self.const_range_contains(&*range, value) {
                     // `value` is not contained in the testing range,
                     // so `value` can be matched only if this test fails.
                     Some(1)
@@ -678,7 +667,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // However, at this point we can still encounter or-patterns that were extracted
                 // from previous calls to `sort_candidate`, so we need to manually address that
                 // case to avoid panicking in `self.test()`.
-                if let PatKind::Or { .. } = &*match_pair.pattern.kind {
+                if let PatKind::Or { .. } = &match_pair.pattern.kind {
                     return None;
                 }
 
@@ -708,9 +697,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         match_pair_index: usize,
         candidate: &mut Candidate<'pat, 'tcx>,
-        prefix: &'pat [Pat<'tcx>],
-        opt_slice: Option<&'pat Pat<'tcx>>,
-        suffix: &'pat [Pat<'tcx>],
+        prefix: &'pat [Box<Pat<'tcx>>],
+        opt_slice: &'pat Option<Box<Pat<'tcx>>>,
+        suffix: &'pat [Box<Pat<'tcx>>],
     ) {
         let removed_place = candidate.match_pairs.remove(match_pair_index).place;
         self.prefix_slice_suffix(
@@ -735,14 +724,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // So, if we have a match-pattern like `x @ Enum::Variant(P1, P2)`,
         // we want to create a set of derived match-patterns like
         // `(x as Variant).0 @ P1` and `(x as Variant).1 @ P1`.
-        let elem =
-            ProjectionElem::Downcast(Some(adt_def.variant(variant_index).name), variant_index);
-        let downcast_place = match_pair.place.project(elem); // `(x as Variant)`
+        let downcast_place = match_pair.place.downcast(adt_def, variant_index); // `(x as Variant)`
         let consequent_match_pairs = subpatterns.iter().map(|subpattern| {
             // e.g., `(x as Variant).0`
             let place = downcast_place.clone().field(subpattern.field, subpattern.pattern.ty);
             // e.g., `(x as Variant).0 @ P1`
-            MatchPair::new(place, &subpattern.pattern)
+            MatchPair::new(place, &subpattern.pattern, self)
         });
 
         candidate.match_pairs.extend(consequent_match_pairs);
@@ -754,7 +741,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
     fn const_range_contains(
         &self,
-        range: PatRange<'tcx>,
+        range: &PatRange<'tcx>,
         value: ConstantKind<'tcx>,
     ) -> Option<bool> {
         use std::cmp::Ordering::*;
@@ -772,7 +759,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
     fn values_not_contained_in_range(
         &self,
-        range: PatRange<'tcx>,
+        range: &PatRange<'tcx>,
         options: &FxIndexMap<ConstantKind<'tcx>, u128>,
     ) -> Option<bool> {
         for &val in options.keys() {
diff --git a/compiler/rustc_mir_build/src/build/matches/util.rs b/compiler/rustc_mir_build/src/build/matches/util.rs
index 9a1e98d3bb18..b854ba47f8f6 100644
--- a/compiler/rustc_mir_build/src/build/matches/util.rs
+++ b/compiler/rustc_mir_build/src/build/matches/util.rs
@@ -1,9 +1,11 @@
+use crate::build::expr::as_place::PlaceBase;
 use crate::build::expr::as_place::PlaceBuilder;
 use crate::build::matches::MatchPair;
 use crate::build::Builder;
 use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty;
+use rustc_middle::ty::TypeVisitable;
 use smallvec::SmallVec;
 use std::convert::TryInto;
 
@@ -17,7 +19,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             .iter()
             .map(|fieldpat| {
                 let place = place.clone().field(fieldpat.field, fieldpat.pattern.ty);
-                MatchPair::new(place, &fieldpat.pattern)
+                MatchPair::new(place, &fieldpat.pattern, self)
             })
             .collect()
     }
@@ -26,32 +28,26 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         match_pairs: &mut SmallVec<[MatchPair<'pat, 'tcx>; 1]>,
         place: &PlaceBuilder<'tcx>,
-        prefix: &'pat [Pat<'tcx>],
-        opt_slice: Option<&'pat Pat<'tcx>>,
-        suffix: &'pat [Pat<'tcx>],
+        prefix: &'pat [Box<Pat<'tcx>>],
+        opt_slice: &'pat Option<Box<Pat<'tcx>>>,
+        suffix: &'pat [Box<Pat<'tcx>>],
     ) {
         let tcx = self.tcx;
-        let (min_length, exact_size) = if let Ok(place_resolved) =
-            place.clone().try_upvars_resolved(tcx, self.typeck_results)
-        {
-            match place_resolved
-                .into_place(tcx, self.typeck_results)
-                .ty(&self.local_decls, tcx)
-                .ty
-                .kind()
-            {
-                ty::Array(_, length) => (length.eval_usize(tcx, self.param_env), true),
-                _ => ((prefix.len() + suffix.len()).try_into().unwrap(), false),
-            }
-        } else {
-            ((prefix.len() + suffix.len()).try_into().unwrap(), false)
-        };
+        let (min_length, exact_size) =
+            if let Ok(place_resolved) = place.clone().try_upvars_resolved(self) {
+                match place_resolved.into_place(self).ty(&self.local_decls, tcx).ty.kind() {
+                    ty::Array(_, length) => (length.eval_usize(tcx, self.param_env), true),
+                    _ => ((prefix.len() + suffix.len()).try_into().unwrap(), false),
+                }
+            } else {
+                ((prefix.len() + suffix.len()).try_into().unwrap(), false)
+            };
 
         match_pairs.extend(prefix.iter().enumerate().map(|(idx, subpattern)| {
             let elem =
                 ProjectionElem::ConstantIndex { offset: idx as u64, min_length, from_end: false };
             let place = place.clone().project(elem);
-            MatchPair::new(place, subpattern)
+            MatchPair::new(place, subpattern, self)
         }));
 
         if let Some(subslice_pat) = opt_slice {
@@ -61,7 +57,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 to: if exact_size { min_length - suffix_len } else { suffix_len },
                 from_end: !exact_size,
             });
-            match_pairs.push(MatchPair::new(subslice, subslice_pat));
+            match_pairs.push(MatchPair::new(subslice, subslice_pat, self));
         }
 
         match_pairs.extend(suffix.iter().rev().enumerate().map(|(idx, subpattern)| {
@@ -72,7 +68,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 from_end: !exact_size,
             };
             let place = place.clone().project(elem);
-            MatchPair::new(place, subpattern)
+            MatchPair::new(place, subpattern, self)
         }));
     }
 
@@ -100,10 +96,29 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 }
 
 impl<'pat, 'tcx> MatchPair<'pat, 'tcx> {
-    pub(crate) fn new(
+    pub(in crate::build) fn new(
         place: PlaceBuilder<'tcx>,
         pattern: &'pat Pat<'tcx>,
+        cx: &Builder<'_, 'tcx>,
     ) -> MatchPair<'pat, 'tcx> {
+        // Force the place type to the pattern's type.
+        // FIXME(oli-obk): can we use this to simplify slice/array pattern hacks?
+        let mut place = match place.try_upvars_resolved(cx) {
+            Ok(val) | Err(val) => val,
+        };
+
+        // Only add the OpaqueCast projection if the given place is an opaque type and the
+        // expected type from the pattern is not.
+        let may_need_cast = match place.base() {
+            PlaceBase::Local(local) => {
+                let ty = Place::ty_from(local, place.projection(), &cx.local_decls, cx.tcx).ty;
+                ty != pattern.ty && ty.has_opaque_types()
+            }
+            _ => true,
+        };
+        if may_need_cast {
+            place = place.project(ProjectionElem::OpaqueCast(pattern.ty));
+        }
         MatchPair { place, pattern }
     }
 }
diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index 684b228e87fa..25c4e51cb925 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -1,15 +1,14 @@
-use crate::build;
 pub(crate) use crate::build::expr::as_constant::lit_to_mir_constant;
 use crate::build::expr::as_place::PlaceBuilder;
 use crate::build::scope::DropKind;
-use crate::thir::pattern::pat_from_hir;
 use rustc_apfloat::ieee::{Double, Single};
 use rustc_apfloat::Float;
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::sorted_map::SortedIndexMultiMap;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::lang_items::LangItem;
 use rustc_hir::{GeneratorKind, Node};
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
@@ -18,8 +17,9 @@ use rustc_middle::middle::region;
 use rustc_middle::mir::interpret::ConstValue;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::*;
-use rustc_middle::thir::{BindingMode, Expr, ExprId, LintLevel, LocalVarId, PatKind, Thir};
-use rustc_middle::ty::subst::Subst;
+use rustc_middle::thir::{
+    self, BindingMode, Expr, ExprId, LintLevel, LocalVarId, Param, ParamId, PatKind, Thir,
+};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable, TypeckResults};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
@@ -47,9 +47,7 @@ pub(crate) fn mir_built<'tcx>(
 
 /// Construct the MIR for a given `DefId`.
 fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
-    let id = tcx.hir().local_def_id_to_hir_id(def.did);
     let body_owner_kind = tcx.hir().body_owner_kind(def.did);
-    let typeck_results = tcx.typeck_opt_const_arg(def);
 
     // Ensure unsafeck and abstract const building is ran before we steal the THIR.
     // We can't use `ensure()` for `thir_abstract_const` as it doesn't compute the query
@@ -66,246 +64,42 @@ fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_
         }
     }
 
-    // Figure out what primary body this item has.
-    let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
-        Node::Expr(hir::Expr {
-            kind: hir::ExprKind::Closure(hir::Closure { fn_decl, body, .. }),
-            ..
-        }) => (*body, fn_decl.output.span(), None),
-        Node::Item(hir::Item {
-            kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
-            span,
-            ..
-        })
-        | Node::ImplItem(hir::ImplItem {
-            kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id),
-            span,
-            ..
-        })
-        | Node::TraitItem(hir::TraitItem {
-            kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)),
-            span,
-            ..
-        }) => {
-            // Use the `Span` of the `Item/ImplItem/TraitItem` as the body span,
-            // since the def span of a function does not include the body
-            (*body_id, decl.output.span(), Some(*span))
-        }
-        Node::Item(hir::Item {
-            kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id),
-            ..
-        })
-        | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
-        | Node::TraitItem(hir::TraitItem {
-            kind: hir::TraitItemKind::Const(ty, Some(body_id)),
-            ..
-        }) => (*body_id, ty.span, None),
-        Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
-            (*body, tcx.hir().span(*hir_id), None)
-        }
+    let body = match tcx.thir_body(def) {
+        Err(error_reported) => construct_error(tcx, def.did, body_owner_kind, error_reported),
+        Ok((thir, expr)) => {
+            // We ran all queries that depended on THIR at the beginning
+            // of `mir_build`, so now we can steal it
+            let thir = thir.steal();
 
-        _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did),
+            if body_owner_kind.is_fn_or_closure() {
+                construct_fn(tcx, def, &thir, expr)
+            } else {
+                construct_const(tcx, def, &thir, expr)
+            }
+        }
     };
 
-    // If we don't have a specialized span for the body, just use the
-    // normal def span.
-    let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
+    lints::check(tcx, &body);
 
-    tcx.infer_ctxt().enter(|infcx| {
-        let body = if let Some(error_reported) = typeck_results.tainted_by_errors {
-            build::construct_error(&infcx, def, id, body_id, body_owner_kind, error_reported)
-        } else if body_owner_kind.is_fn_or_closure() {
-            // fetch the fully liberated fn signature (that is, all bound
-            // types/lifetimes replaced)
-            let fn_sig = typeck_results.liberated_fn_sigs()[id];
-            let fn_def_id = tcx.hir().local_def_id(id);
+    // The borrow checker will replace all the regions here with its own
+    // inference variables. There's no point having non-erased regions here.
+    // The exception is `body.user_type_annotations`, which is used unmodified
+    // by borrow checking.
+    debug_assert!(
+        !(body.local_decls.has_free_regions()
+            || body.basic_blocks.has_free_regions()
+            || body.var_debug_info.has_free_regions()
+            || body.yield_ty().has_free_regions()),
+        "Unexpected free regions in MIR: {:?}",
+        body,
+    );
 
-            let safety = match fn_sig.unsafety {
-                hir::Unsafety::Normal => Safety::Safe,
-                hir::Unsafety::Unsafe => Safety::FnUnsafe,
-            };
-
-            let body = tcx.hir().body(body_id);
-            let (thir, expr) = tcx
-                .thir_body(def)
-                .unwrap_or_else(|_| (tcx.alloc_steal_thir(Thir::new()), ExprId::from_u32(0)));
-            // We ran all queries that depended on THIR at the beginning
-            // of `mir_build`, so now we can steal it
-            let thir = thir.steal();
-            let ty = tcx.type_of(fn_def_id);
-            let mut abi = fn_sig.abi;
-            let implicit_argument = match ty.kind() {
-                ty::Closure(..) => {
-                    // HACK(eddyb) Avoid having RustCall on closures,
-                    // as it adds unnecessary (and wrong) auto-tupling.
-                    abi = Abi::Rust;
-                    vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
-                }
-                ty::Generator(..) => {
-                    let gen_ty = tcx.typeck_body(body_id).node_type(id);
-
-                    // The resume argument may be missing, in that case we need to provide it here.
-                    // It will always be `()` in this case.
-                    if body.params.is_empty() {
-                        vec![
-                            ArgInfo(gen_ty, None, None, None),
-                            ArgInfo(tcx.mk_unit(), None, None, None),
-                        ]
-                    } else {
-                        vec![ArgInfo(gen_ty, None, None, None)]
-                    }
-                }
-                _ => vec![],
-            };
-
-            let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
-                let owner_id = tcx.hir().body_owner(body_id);
-                let opt_ty_info;
-                let self_arg;
-                if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
-                    opt_ty_info = fn_decl
-                        .inputs
-                        .get(index)
-                        // Make sure that inferred closure args have no type span
-                        .and_then(|ty| if arg.pat.span != ty.span { Some(ty.span) } else { None });
-                    self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
-                        match fn_decl.implicit_self {
-                            hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
-                            hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
-                            hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
-                            hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
-                            _ => None,
-                        }
-                    } else {
-                        None
-                    };
-                } else {
-                    opt_ty_info = None;
-                    self_arg = None;
-                }
-
-                // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
-                // (as it's created inside the body itself, not passed in from outside).
-                let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
-                    let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span));
-
-                    tcx.bound_type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()])
-                } else {
-                    fn_sig.inputs()[index]
-                };
-
-                ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
-            });
-
-            let arguments = implicit_argument.into_iter().chain(explicit_arguments);
-
-            let (yield_ty, return_ty) = if body.generator_kind.is_some() {
-                let gen_ty = tcx.typeck_body(body_id).node_type(id);
-                let gen_sig = match gen_ty.kind() {
-                    ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
-                    _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
-                };
-                (Some(gen_sig.yield_ty), gen_sig.return_ty)
-            } else {
-                (None, fn_sig.output())
-            };
-
-            let mut mir = build::construct_fn(
-                &thir,
-                &infcx,
-                def,
-                id,
-                arguments,
-                safety,
-                abi,
-                return_ty,
-                return_ty_span,
-                body,
-                expr,
-                span_with_body,
-            );
-            if yield_ty.is_some() {
-                mir.generator.as_mut().unwrap().yield_ty = yield_ty;
-            }
-            mir
-        } else {
-            // Get the revealed type of this const. This is *not* the adjusted
-            // type of its body, which may be a subtype of this type. For
-            // example:
-            //
-            // fn foo(_: &()) {}
-            // static X: fn(&'static ()) = foo;
-            //
-            // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
-            // is not the same as the type of X. We need the type of the return
-            // place to be the type of the constant because NLL typeck will
-            // equate them.
-
-            let return_ty = typeck_results.node_type(id);
-
-            let (thir, expr) = tcx
-                .thir_body(def)
-                .unwrap_or_else(|_| (tcx.alloc_steal_thir(Thir::new()), ExprId::from_u32(0)));
-            // We ran all queries that depended on THIR at the beginning
-            // of `mir_build`, so now we can steal it
-            let thir = thir.steal();
-
-            let span_with_body = span_with_body.to(tcx.hir().span(body_id.hir_id));
-
-            build::construct_const(
-                &thir,
-                &infcx,
-                expr,
-                def,
-                id,
-                return_ty,
-                return_ty_span,
-                span_with_body,
-            )
-        };
-
-        lints::check(tcx, &body);
-
-        // The borrow checker will replace all the regions here with its own
-        // inference variables. There's no point having non-erased regions here.
-        // The exception is `body.user_type_annotations`, which is used unmodified
-        // by borrow checking.
-        debug_assert!(
-            !(body.local_decls.has_free_regions()
-                || body.basic_blocks.has_free_regions()
-                || body.var_debug_info.has_free_regions()
-                || body.yield_ty().has_free_regions()),
-            "Unexpected free regions in MIR: {:?}",
-            body,
-        );
-
-        body
-    })
+    body
 }
 
 ///////////////////////////////////////////////////////////////////////////
 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
 
-fn liberated_closure_env_ty(
-    tcx: TyCtxt<'_>,
-    closure_expr_id: hir::HirId,
-    body_id: hir::BodyId,
-) -> Ty<'_> {
-    let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id);
-
-    let ty::Closure(closure_def_id, closure_substs) = *closure_ty.kind() else {
-        bug!("closure expr does not have closure type: {:?}", closure_ty);
-    };
-
-    let bound_vars =
-        tcx.mk_bound_variable_kinds(std::iter::once(ty::BoundVariableKind::Region(ty::BrEnv)));
-    let br =
-        ty::BoundRegion { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind: ty::BrEnv };
-    let env_region = ty::ReLateBound(ty::INNERMOST, br);
-    let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs, env_region).unwrap();
-    tcx.erase_late_bound_regions(ty::Binder::bind_with_vars(closure_env_ty, bound_vars))
-}
-
 #[derive(Debug, PartialEq, Eq)]
 enum BlockFrame {
     /// Evaluation is currently within a statement.
@@ -363,7 +157,7 @@ struct BlockContext(Vec<BlockFrame>);
 
 struct Builder<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    infcx: &'a InferCtxt<'a, 'tcx>,
+    infcx: InferCtxt<'a, 'tcx>,
     typeck_results: &'tcx TypeckResults<'tcx>,
     region_scope_tree: &'tcx region::ScopeTree,
     param_env: ty::ParamEnv<'tcx>,
@@ -415,12 +209,21 @@ struct Builder<'a, 'tcx> {
     var_indices: FxHashMap<LocalVarId, LocalsForNode>,
     local_decls: IndexVec<Local, LocalDecl<'tcx>>,
     canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
-    upvar_mutbls: Vec<Mutability>,
+    upvars: CaptureMap<'tcx>,
     unit_temp: Option<Place<'tcx>>,
 
     var_debug_info: Vec<VarDebugInfo<'tcx>>,
 }
 
+type CaptureMap<'tcx> = SortedIndexMultiMap<usize, hir::HirId, Capture<'tcx>>;
+
+#[derive(Debug)]
+struct Capture<'tcx> {
+    captured_place: &'tcx ty::CapturedPlace<'tcx>,
+    use_place: Place<'tcx>,
+    mutability: Mutability,
+}
+
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     fn is_bound_var_in_guard(&self, id: LocalVarId) -> bool {
         self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
@@ -626,148 +429,212 @@ macro_rules! unpack {
 ///////////////////////////////////////////////////////////////////////////
 /// the main entry point for building MIR for a function
 
-struct ArgInfo<'tcx>(
-    Ty<'tcx>,
-    Option<Span>,
-    Option<&'tcx hir::Param<'tcx>>,
-    Option<ImplicitSelfKind>,
-);
-
-fn construct_fn<'tcx, A>(
-    thir: &Thir<'tcx>,
-    infcx: &InferCtxt<'_, 'tcx>,
+fn construct_fn<'tcx>(
+    tcx: TyCtxt<'tcx>,
     fn_def: ty::WithOptConstParam<LocalDefId>,
-    fn_id: hir::HirId,
-    arguments: A,
-    safety: Safety,
-    abi: Abi,
-    return_ty: Ty<'tcx>,
-    return_ty_span: Span,
-    body: &'tcx hir::Body<'tcx>,
+    thir: &Thir<'tcx>,
     expr: ExprId,
-    span_with_body: Span,
-) -> Body<'tcx>
-where
-    A: Iterator<Item = ArgInfo<'tcx>>,
-{
-    let arguments: Vec<_> = arguments.collect();
+) -> Body<'tcx> {
+    let span = tcx.def_span(fn_def.did);
+    let fn_id = tcx.hir().local_def_id_to_hir_id(fn_def.did);
+    let generator_kind = tcx.generator_kind(fn_def.did);
 
-    let tcx = infcx.tcx;
-    let span = tcx.hir().span(fn_id);
+    // Figure out what primary body this item has.
+    let body_id = tcx.hir().body_owned_by(fn_def.did);
+    let span_with_body = tcx.hir().span_with_body(fn_id);
+    let return_ty_span = tcx
+        .hir()
+        .fn_decl_by_hir_id(fn_id)
+        .unwrap_or_else(|| span_bug!(span, "can't build MIR for {:?}", fn_def.did))
+        .output
+        .span();
 
-    let mut builder = Builder::new(
-        thir,
-        infcx,
-        fn_def,
-        fn_id,
-        span_with_body,
-        arguments.len(),
-        safety,
-        return_ty,
-        return_ty_span,
-        body.generator_kind,
-    );
+    // fetch the fully liberated fn signature (that is, all bound
+    // types/lifetimes replaced)
+    let typeck_results = tcx.typeck_opt_const_arg(fn_def);
+    let fn_sig = typeck_results.liberated_fn_sigs()[fn_id];
 
-    let call_site_scope =
-        region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
-    let arg_scope =
-        region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
-    let source_info = builder.source_info(span);
-    let call_site_s = (call_site_scope, source_info);
-    unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
-        let arg_scope_s = (arg_scope, source_info);
-        // Attribute epilogue to function's closing brace
-        let fn_end = span_with_body.shrink_to_hi();
-        let return_block =
-            unpack!(builder.in_breakable_scope(None, Place::return_place(), fn_end, |builder| {
-                Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
-                    builder.args_and_body(
-                        START_BLOCK,
-                        fn_def.did,
-                        &arguments,
-                        arg_scope,
-                        &thir[expr],
-                    )
-                }))
-            }));
-        let source_info = builder.source_info(fn_end);
-        builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
-        builder.build_drop_trees();
-        return_block.unit()
-    }));
+    let safety = match fn_sig.unsafety {
+        hir::Unsafety::Normal => Safety::Safe,
+        hir::Unsafety::Unsafe => Safety::FnUnsafe,
+    };
 
-    let spread_arg = if abi == Abi::RustCall {
+    let mut abi = fn_sig.abi;
+    if let DefKind::Closure = tcx.def_kind(fn_def.did) {
+        // HACK(eddyb) Avoid having RustCall on closures,
+        // as it adds unnecessary (and wrong) auto-tupling.
+        abi = Abi::Rust;
+    }
+
+    let arguments = &thir.params;
+
+    let (yield_ty, return_ty) = if generator_kind.is_some() {
+        let gen_ty = arguments[thir::UPVAR_ENV_PARAM].ty;
+        let gen_sig = match gen_ty.kind() {
+            ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
+            _ => {
+                span_bug!(span, "generator w/o generator type: {:?}", gen_ty)
+            }
+        };
+        (Some(gen_sig.yield_ty), gen_sig.return_ty)
+    } else {
+        (None, fn_sig.output())
+    };
+
+    let mut body = tcx.infer_ctxt().enter(|infcx| {
+        let mut builder = Builder::new(
+            thir,
+            infcx,
+            fn_def,
+            fn_id,
+            span_with_body,
+            arguments.len(),
+            safety,
+            return_ty,
+            return_ty_span,
+            generator_kind,
+        );
+
+        let call_site_scope =
+            region::Scope { id: body_id.hir_id.local_id, data: region::ScopeData::CallSite };
+        let arg_scope =
+            region::Scope { id: body_id.hir_id.local_id, data: region::ScopeData::Arguments };
+        let source_info = builder.source_info(span);
+        let call_site_s = (call_site_scope, source_info);
+        unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
+            let arg_scope_s = (arg_scope, source_info);
+            // Attribute epilogue to function's closing brace
+            let fn_end = span_with_body.shrink_to_hi();
+            let return_block = unpack!(builder.in_breakable_scope(
+                None,
+                Place::return_place(),
+                fn_end,
+                |builder| {
+                    Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
+                        builder.args_and_body(
+                            START_BLOCK,
+                            fn_def.did,
+                            arguments,
+                            arg_scope,
+                            &thir[expr],
+                        )
+                    }))
+                }
+            ));
+            let source_info = builder.source_info(fn_end);
+            builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
+            builder.build_drop_trees();
+            return_block.unit()
+        }));
+
+        builder.finish()
+    });
+
+    body.spread_arg = if abi == Abi::RustCall {
         // RustCall pseudo-ABI untuples the last argument.
         Some(Local::new(arguments.len()))
     } else {
         None
     };
-
-    let mut body = builder.finish();
-    body.spread_arg = spread_arg;
+    if yield_ty.is_some() {
+        body.generator.as_mut().unwrap().yield_ty = yield_ty;
+    }
     body
 }
 
 fn construct_const<'a, 'tcx>(
-    thir: &'a Thir<'tcx>,
-    infcx: &'a InferCtxt<'a, 'tcx>,
-    expr: ExprId,
+    tcx: TyCtxt<'tcx>,
     def: ty::WithOptConstParam<LocalDefId>,
-    hir_id: hir::HirId,
-    const_ty: Ty<'tcx>,
-    const_ty_span: Span,
-    span: Span,
+    thir: &'a Thir<'tcx>,
+    expr: ExprId,
 ) -> Body<'tcx> {
-    let mut builder = Builder::new(
-        thir,
-        infcx,
-        def,
-        hir_id,
-        span,
-        0,
-        Safety::Safe,
-        const_ty,
-        const_ty_span,
-        None,
-    );
+    let hir_id = tcx.hir().local_def_id_to_hir_id(def.did);
 
-    let mut block = START_BLOCK;
-    unpack!(block = builder.expr_into_dest(Place::return_place(), block, &thir[expr]));
+    // Figure out what primary body this item has.
+    let (span, const_ty_span) = match tcx.hir().get(hir_id) {
+        Node::Item(hir::Item {
+            kind: hir::ItemKind::Static(ty, _, _) | hir::ItemKind::Const(ty, _),
+            span,
+            ..
+        })
+        | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, _), span, .. })
+        | Node::TraitItem(hir::TraitItem {
+            kind: hir::TraitItemKind::Const(ty, Some(_)),
+            span,
+            ..
+        }) => (*span, ty.span),
+        Node::AnonConst(_) => {
+            let span = tcx.def_span(def.did);
+            (span, span)
+        }
+        _ => span_bug!(tcx.def_span(def.did), "can't build MIR for {:?}", def.did),
+    };
 
-    let source_info = builder.source_info(span);
-    builder.cfg.terminate(block, source_info, TerminatorKind::Return);
+    // Get the revealed type of this const. This is *not* the adjusted
+    // type of its body, which may be a subtype of this type. For
+    // example:
+    //
+    // fn foo(_: &()) {}
+    // static X: fn(&'static ()) = foo;
+    //
+    // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
+    // is not the same as the type of X. We need the type of the return
+    // place to be the type of the constant because NLL typeck will
+    // equate them.
+    let typeck_results = tcx.typeck_opt_const_arg(def);
+    let const_ty = typeck_results.node_type(hir_id);
 
-    builder.build_drop_trees();
+    tcx.infer_ctxt().enter(|infcx| {
+        let mut builder = Builder::new(
+            thir,
+            infcx,
+            def,
+            hir_id,
+            span,
+            0,
+            Safety::Safe,
+            const_ty,
+            const_ty_span,
+            None,
+        );
 
-    builder.finish()
+        let mut block = START_BLOCK;
+        unpack!(block = builder.expr_into_dest(Place::return_place(), block, &thir[expr]));
+
+        let source_info = builder.source_info(span);
+        builder.cfg.terminate(block, source_info, TerminatorKind::Return);
+
+        builder.build_drop_trees();
+
+        builder.finish()
+    })
 }
 
 /// Construct MIR for an item that has had errors in type checking.
 ///
 /// This is required because we may still want to run MIR passes on an item
 /// with type errors, but normal MIR construction can't handle that in general.
-fn construct_error<'a, 'tcx>(
-    infcx: &'a InferCtxt<'a, 'tcx>,
-    def: ty::WithOptConstParam<LocalDefId>,
-    hir_id: hir::HirId,
-    body_id: hir::BodyId,
+fn construct_error<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    def: LocalDefId,
     body_owner_kind: hir::BodyOwnerKind,
     err: ErrorGuaranteed,
 ) -> Body<'tcx> {
-    let tcx = infcx.tcx;
-    let span = tcx.hir().span(hir_id);
+    let span = tcx.def_span(def);
+    let hir_id = tcx.hir().local_def_id_to_hir_id(def);
+    let generator_kind = tcx.generator_kind(def);
+
     let ty = tcx.ty_error();
-    let generator_kind = tcx.hir().body(body_id).generator_kind;
     let num_params = match body_owner_kind {
-        hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len(),
+        hir::BodyOwnerKind::Fn => tcx.fn_sig(def).inputs().skip_binder().len(),
         hir::BodyOwnerKind::Closure => {
-            if generator_kind.is_some() {
-                // Generators have an implicit `self` parameter *and* a possibly
-                // implicit resume parameter.
-                2
-            } else {
-                // The implicit self parameter adds another local in MIR.
-                1 + tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len()
+            let ty = tcx.type_of(def);
+            match ty.kind() {
+                ty::Closure(_, substs) => {
+                    1 + substs.as_closure().sig().inputs().skip_binder().len()
+                }
+                ty::Generator(..) => 2,
+                _ => bug!("expected closure or generator, found {ty:?}"),
             }
         }
         hir::BodyOwnerKind::Const => 0,
@@ -798,7 +665,7 @@ fn construct_error<'a, 'tcx>(
     cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
 
     let mut body = Body::new(
-        MirSource::item(def.did.to_def_id()),
+        MirSource::item(def.to_def_id()),
         cfg.basic_blocks,
         source_scopes,
         local_decls,
@@ -816,7 +683,7 @@ fn construct_error<'a, 'tcx>(
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     fn new(
         thir: &'a Thir<'tcx>,
-        infcx: &'a InferCtxt<'a, 'tcx>,
+        infcx: InferCtxt<'a, 'tcx>,
         def: ty::WithOptConstParam<LocalDefId>,
         hir_id: hir::HirId,
         span: Span,
@@ -865,7 +732,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             in_scope_unsafe: safety,
             local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1),
             canonical_user_type_annotations: IndexVec::new(),
-            upvar_mutbls: vec![],
+            upvars: CaptureMap::new(),
             var_indices: Default::default(),
             unit_temp: None,
             var_debug_info: vec![],
@@ -906,20 +773,21 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         mut block: BasicBlock,
         fn_def_id: LocalDefId,
-        arguments: &[ArgInfo<'tcx>],
+        arguments: &IndexVec<ParamId, Param<'tcx>>,
         argument_scope: region::Scope,
         expr: &Expr<'tcx>,
     ) -> BlockAnd<()> {
         // Allocate locals for the function arguments
-        for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
+        for param in arguments.iter() {
             let source_info =
-                SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span));
-            let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info));
+                SourceInfo::outermost(param.pat.as_ref().map_or(self.fn_span, |pat| pat.span));
+            let arg_local =
+                self.local_decls.push(LocalDecl::with_source_info(param.ty, source_info));
 
             // If this is a simple binding pattern, give debuginfo a nice name.
-            if let Some(arg) = arg_opt && let Some(ident) = arg.pat.simple_ident() {
+            if let Some(ref pat) = param.pat && let Some(name) = pat.simple_ident() {
                 self.var_debug_info.push(VarDebugInfo {
-                    name: ident.name,
+                    name,
                     source_info,
                     value: VarDebugInfoContents::Place(arg_local.into()),
                 });
@@ -934,7 +802,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         // indexed closure and we stored in a map called closure_min_captures in TypeckResults
         // with the closure's DefId. Here, we run through that vec of UpvarIds for
         // the given closure and use the necessary information to create upvar
-        // debuginfo and to fill `self.upvar_mutbls`.
+        // debuginfo and to fill `self.upvars`.
         if hir_typeck_results.closure_min_captures.get(&fn_def_id).is_some() {
             let mut closure_env_projs = vec![];
             let mut closure_ty = self.local_decls[ty::CAPTURE_STRUCT_LOCAL].ty;
@@ -954,7 +822,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 .closure_min_captures_flattened(fn_def_id)
                 .zip(capture_tys.zip(capture_syms));
 
-            self.upvar_mutbls = captures_with_tys
+            self.upvars = captures_with_tys
                 .enumerate()
                 .map(|(i, (captured_place, (ty, sym)))| {
                     let capture = captured_place.info.capture_kind;
@@ -974,48 +842,46 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         }
                     };
 
+                    let use_place = Place {
+                        local: ty::CAPTURE_STRUCT_LOCAL,
+                        projection: tcx.intern_place_elems(&projs),
+                    };
                     self.var_debug_info.push(VarDebugInfo {
                         name: *sym,
                         source_info: SourceInfo::outermost(tcx_hir.span(var_id)),
-                        value: VarDebugInfoContents::Place(Place {
-                            local: ty::CAPTURE_STRUCT_LOCAL,
-                            projection: tcx.intern_place_elems(&projs),
-                        }),
+                        value: VarDebugInfoContents::Place(use_place),
                     });
 
-                    mutability
+                    let capture = Capture { captured_place, use_place, mutability };
+                    (var_id, capture)
                 })
                 .collect();
         }
 
         let mut scope = None;
         // Bind the argument patterns
-        for (index, arg_info) in arguments.iter().enumerate() {
+        for (index, param) in arguments.iter().enumerate() {
             // Function arguments always get the first Local indices after the return place
             let local = Local::new(index + 1);
             let place = Place::from(local);
-            let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
 
             // Make sure we drop (parts of) the argument even when not matched on.
             self.schedule_drop(
-                arg_opt.as_ref().map_or(expr.span, |arg| arg.pat.span),
+                param.pat.as_ref().map_or(expr.span, |pat| pat.span),
                 argument_scope,
                 local,
                 DropKind::Value,
             );
 
-            let Some(arg) = arg_opt else {
+            let Some(ref pat) = param.pat else {
                 continue;
             };
-            let pat = match tcx.hir().get(arg.pat.hir_id) {
-                Node::Pat(pat) => pat,
-                node => bug!("pattern became {:?}", node),
-            };
-            let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat);
             let original_source_scope = self.source_scope;
-            let span = pattern.span;
-            self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
-            match *pattern.kind {
+            let span = pat.span;
+            if let Some(arg_hir_id) = param.hir_id {
+                self.set_correct_source_scope_for_arg(arg_hir_id, original_source_scope, span);
+            }
+            match pat.kind {
                 // Don't introduce extra copies for simple bindings
                 PatKind::Binding {
                     mutability,
@@ -1026,17 +892,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 } => {
                     self.local_decls[local].mutability = mutability;
                     self.local_decls[local].source_info.scope = self.source_scope;
-                    self.local_decls[local].local_info = if let Some(kind) = self_binding {
+                    self.local_decls[local].local_info = if let Some(kind) = param.self_kind {
                         Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(
-                            BindingForm::ImplicitSelf(*kind),
+                            BindingForm::ImplicitSelf(kind),
                         ))))
                     } else {
                         let binding_mode = ty::BindingMode::BindByValue(mutability);
                         Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
                             VarBindingForm {
                                 binding_mode,
-                                opt_ty_info,
-                                opt_match_place: Some((Some(place), span)),
+                                opt_ty_info: param.ty_span,
+                                opt_match_place: Some((None, span)),
                                 pat_span: span,
                             },
                         )))))
@@ -1047,12 +913,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     scope = self.declare_bindings(
                         scope,
                         expr.span,
-                        &pattern,
+                        &pat,
                         matches::ArmHasGuard(false),
                         Some((Some(&place), span)),
                     );
                     let place_builder = PlaceBuilder::from(local);
-                    unpack!(block = self.place_into_pattern(block, pattern, place_builder, false));
+                    unpack!(block = self.place_into_pattern(block, &pat, place_builder, false));
                 }
             }
             self.source_scope = original_source_scope;
diff --git a/compiler/rustc_mir_build/src/build/scope.rs b/compiler/rustc_mir_build/src/build/scope.rs
index b2fd9f25bdde..2c7d6a572f45 100644
--- a/compiler/rustc_mir_build/src/build/scope.rs
+++ b/compiler/rustc_mir_build/src/build/scope.rs
@@ -553,6 +553,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
     /// Convenience wrapper that pushes a scope and then executes `f`
     /// to build its contents, popping the scope afterwards.
+    #[instrument(skip(self, f), level = "debug")]
     pub(crate) fn in_scope<F, R>(
         &mut self,
         region_scope: (region::Scope, SourceInfo),
@@ -562,7 +563,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     where
         F: FnOnce(&mut Builder<'a, 'tcx>) -> BlockAnd<R>,
     {
-        debug!("in_scope(region_scope={:?})", region_scope);
         let source_scope = self.source_scope;
         let tcx = self.tcx;
         if let LintLevel::Explicit(current_hir_id) = lint_level {
@@ -589,7 +589,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let rv = unpack!(block = f(self));
         unpack!(block = self.pop_scope(region_scope, block));
         self.source_scope = source_scope;
-        debug!("in_scope: exiting region_scope={:?} block={:?}", region_scope, block);
+        debug!(?block);
         block.and(rv)
     }
 
diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs
index bf5a2e7c73fa..495738ebe1c7 100644
--- a/compiler/rustc_mir_build/src/check_unsafety.rs
+++ b/compiler/rustc_mir_build/src/check_unsafety.rs
@@ -214,7 +214,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
 
     fn visit_pat(&mut self, pat: &Pat<'tcx>) {
         if self.in_union_destructure {
-            match *pat.kind {
+            match pat.kind {
                 // binding to a variable allows getting stuff out of variable
                 PatKind::Binding { .. }
                 // match is conditional on having this value
@@ -236,7 +236,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             }
         };
 
-        match &*pat.kind {
+        match &pat.kind {
             PatKind::Leaf { .. } => {
                 if let ty::Adt(adt_def, ..) = pat.ty.kind() {
                     if adt_def.is_union() {
diff --git a/compiler/rustc_mir_build/src/lib.rs b/compiler/rustc_mir_build/src/lib.rs
index 11cd2a9aa4de..8236b1528c0e 100644
--- a/compiler/rustc_mir_build/src/lib.rs
+++ b/compiler/rustc_mir_build/src/lib.rs
@@ -6,7 +6,6 @@
 #![feature(control_flow_enum)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_mir_build/src/thir/cx/block.rs b/compiler/rustc_mir_build/src/thir/cx/block.rs
index 54c4b9eda70d..321353ca20ba 100644
--- a/compiler/rustc_mir_build/src/thir/cx/block.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/block.rs
@@ -87,21 +87,21 @@ impl<'tcx> Cx<'tcx> {
                             {
                                 debug!("mirror_stmts: user_ty={:?}", user_ty);
                                 let annotation = CanonicalUserTypeAnnotation {
-                                    user_ty,
+                                    user_ty: Box::new(user_ty),
                                     span: ty.span,
                                     inferred_ty: self.typeck_results.node_type(ty.hir_id),
                                 };
-                                pattern = Pat {
+                                pattern = Box::new(Pat {
                                     ty: pattern.ty,
                                     span: pattern.span,
-                                    kind: Box::new(PatKind::AscribeUserType {
+                                    kind: PatKind::AscribeUserType {
                                         ascription: Ascription {
                                             annotation,
                                             variance: ty::Variance::Covariant,
                                         },
                                         subpattern: pattern,
-                                    }),
-                                };
+                                    },
+                                });
                             }
                         }
 
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index 0c2b117453fe..3f8a9d21cd8d 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -48,6 +48,8 @@ impl<'tcx> Cx<'tcx> {
             _ => None,
         };
 
+        trace!(?expr.ty);
+
         // Now apply adjustments, if any.
         for adjustment in self.typeck_results.expr_adjustments(hir_expr) {
             trace!(?expr, ?adjustment);
@@ -56,6 +58,8 @@ impl<'tcx> Cx<'tcx> {
                 self.apply_adjustment(hir_expr, expr, adjustment, adjustment_span.unwrap_or(span));
         }
 
+        trace!(?expr.ty, "after adjustments");
+
         // Next, wrap this up in the expr's scope.
         expr = Expr {
             temp_lifetime,
@@ -261,15 +265,19 @@ impl<'tcx> Cx<'tcx> {
 
         let kind = match expr.kind {
             // Here comes the interesting stuff:
-            hir::ExprKind::MethodCall(segment, ref args, fn_span) => {
+            hir::ExprKind::MethodCall(segment, receiver, ref args, fn_span) => {
                 // Rewrite a.b(c) into UFCS form like Trait::b(a, c)
                 let expr = self.method_callee(expr, segment.ident.span, None);
                 // When we apply adjustments to the receiver, use the span of
                 // the overall method call for better diagnostics. args[0]
                 // is guaranteed to exist, since a method call always has a receiver.
-                let old_adjustment_span = self.adjustment_span.replace((args[0].hir_id, expr_span));
-                tracing::info!("Using method span: {:?}", expr.span);
-                let args = self.mirror_exprs(args);
+                let old_adjustment_span =
+                    self.adjustment_span.replace((receiver.hir_id, expr_span));
+                info!("Using method span: {:?}", expr.span);
+                let args = std::iter::once(receiver)
+                    .chain(args.iter())
+                    .map(|expr| self.mirror_expr(expr))
+                    .collect();
                 self.adjustment_span = old_adjustment_span;
                 ExprKind::Call {
                     ty: expr.ty,
diff --git a/compiler/rustc_mir_build/src/thir/cx/mod.rs b/compiler/rustc_mir_build/src/thir/cx/mod.rs
index f7351a4caa95..1d95d6b53fbe 100644
--- a/compiler/rustc_mir_build/src/thir/cx/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/mod.rs
@@ -8,7 +8,9 @@ use crate::thir::util::UserAnnotatedTyHelpers;
 use rustc_data_structures::steal::Steal;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::lang_items::LangItem;
 use rustc_hir::HirId;
 use rustc_hir::Node;
 use rustc_middle::middle::region;
@@ -27,6 +29,26 @@ pub(crate) fn thir_body<'tcx>(
         return Err(reported);
     }
     let expr = cx.mirror_expr(&body.value);
+
+    let owner_id = hir.local_def_id_to_hir_id(owner_def.did);
+    if let Some(ref fn_decl) = hir.fn_decl_by_hir_id(owner_id) {
+        let closure_env_param = cx.closure_env_param(owner_def.did, owner_id);
+        let explicit_params = cx.explicit_params(owner_id, fn_decl, body);
+        cx.thir.params = closure_env_param.into_iter().chain(explicit_params).collect();
+
+        // The resume argument may be missing, in that case we need to provide it here.
+        // It will always be `()` in this case.
+        if tcx.def_kind(owner_def.did) == DefKind::Generator && body.params.is_empty() {
+            cx.thir.params.push(Param {
+                ty: tcx.mk_unit(),
+                pat: None,
+                ty_span: None,
+                self_kind: None,
+                hir_id: None,
+            });
+        }
+    }
+
     Ok((tcx.alloc_steal_thir(cx.thir), expr))
 }
 
@@ -44,11 +66,11 @@ struct Cx<'tcx> {
     tcx: TyCtxt<'tcx>,
     thir: Thir<'tcx>,
 
-    pub(crate) param_env: ty::ParamEnv<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
 
-    pub(crate) region_scope_tree: &'tcx region::ScopeTree,
-    pub(crate) typeck_results: &'tcx ty::TypeckResults<'tcx>,
-    pub(crate) rvalue_scopes: &'tcx RvalueScopes,
+    region_scope_tree: &'tcx region::ScopeTree,
+    typeck_results: &'tcx ty::TypeckResults<'tcx>,
+    rvalue_scopes: &'tcx RvalueScopes,
 
     /// When applying adjustments to the expression
     /// with the given `HirId`, use the given `Span`,
@@ -77,14 +99,94 @@ impl<'tcx> Cx<'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
-    pub(crate) fn pattern_from_hir(&mut self, p: &hir::Pat<'_>) -> Pat<'tcx> {
+    #[instrument(level = "debug", skip(self))]
+    fn pattern_from_hir(&mut self, p: &hir::Pat<'_>) -> Box<Pat<'tcx>> {
         let p = match self.tcx.hir().get(p.hir_id) {
             Node::Pat(p) => p,
             node => bug!("pattern became {:?}", node),
         };
         pat_from_hir(self.tcx, self.param_env, self.typeck_results(), p)
     }
+
+    fn closure_env_param(&self, owner_def: LocalDefId, owner_id: HirId) -> Option<Param<'tcx>> {
+        match self.tcx.def_kind(owner_def) {
+            DefKind::Closure => {
+                let closure_ty = self.typeck_results.node_type(owner_id);
+
+                let ty::Closure(closure_def_id, closure_substs) = *closure_ty.kind() else {
+                    bug!("closure expr does not have closure type: {:?}", closure_ty);
+                };
+
+                let bound_vars = self.tcx.mk_bound_variable_kinds(std::iter::once(
+                    ty::BoundVariableKind::Region(ty::BrEnv),
+                ));
+                let br = ty::BoundRegion {
+                    var: ty::BoundVar::from_usize(bound_vars.len() - 1),
+                    kind: ty::BrEnv,
+                };
+                let env_region = ty::ReLateBound(ty::INNERMOST, br);
+                let closure_env_ty =
+                    self.tcx.closure_env_ty(closure_def_id, closure_substs, env_region).unwrap();
+                let liberated_closure_env_ty = self.tcx.erase_late_bound_regions(
+                    ty::Binder::bind_with_vars(closure_env_ty, bound_vars),
+                );
+                let env_param = Param {
+                    ty: liberated_closure_env_ty,
+                    pat: None,
+                    ty_span: None,
+                    self_kind: None,
+                    hir_id: None,
+                };
+
+                Some(env_param)
+            }
+            DefKind::Generator => {
+                let gen_ty = self.typeck_results.node_type(owner_id);
+                let gen_param =
+                    Param { ty: gen_ty, pat: None, ty_span: None, self_kind: None, hir_id: None };
+                Some(gen_param)
+            }
+            _ => None,
+        }
+    }
+
+    fn explicit_params<'a>(
+        &'a mut self,
+        owner_id: HirId,
+        fn_decl: &'tcx hir::FnDecl<'tcx>,
+        body: &'tcx hir::Body<'tcx>,
+    ) -> impl Iterator<Item = Param<'tcx>> + 'a {
+        let fn_sig = self.typeck_results.liberated_fn_sigs()[owner_id];
+
+        body.params.iter().enumerate().map(move |(index, param)| {
+            let ty_span = fn_decl
+                .inputs
+                .get(index)
+                // Make sure that inferred closure args have no type span
+                .and_then(|ty| if param.pat.span != ty.span { Some(ty.span) } else { None });
+
+            let self_kind = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
+                Some(fn_decl.implicit_self)
+            } else {
+                None
+            };
+
+            // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
+            // (as it's created inside the body itself, not passed in from outside).
+            let ty = if fn_decl.c_variadic && index == fn_decl.inputs.len() {
+                let va_list_did = self.tcx.require_lang_item(LangItem::VaList, Some(param.span));
+
+                self.tcx
+                    .bound_type_of(va_list_did)
+                    .subst(self.tcx, &[self.tcx.lifetimes.re_erased.into()])
+            } else {
+                fn_sig.inputs()[index]
+            };
+
+            let pat = self.pattern_from_hir(param.pat);
+            Param { pat: Some(pat), ty, ty_span, self_kind, hir_id: Some(param.hir_id) }
+        })
+    }
 }
 
 impl<'tcx> UserAnnotatedTyHelpers<'tcx> for Cx<'tcx> {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index 69a8c98b27a3..d45b886903bb 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -491,8 +491,8 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
                     err.span_suggestion_verbose(
                         semi_span.shrink_to_lo(),
                         &format!(
-                            "alternatively, on nightly, you might want to use \
-                             `#![feature(let_else)]` to handle the variant{} that {} matched",
+                            "alternatively, you might want to use \
+                             let else to handle the variant{} that {} matched",
                             pluralize!(witnesses.len()),
                             match witnesses.len() {
                                 1 => "isn't",
diff --git a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
index f2045ac19cac..b58685e89580 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
@@ -19,21 +19,18 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
     /// Converts an evaluated constant to a pattern (if possible).
     /// This means aggregate values (like structs and enums) are converted
     /// to a pattern that matches the value (as if you'd compared via structural equality).
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     pub(super) fn const_to_pat(
         &self,
         cv: mir::ConstantKind<'tcx>,
         id: hir::HirId,
         span: Span,
         mir_structural_match_violation: bool,
-    ) -> Pat<'tcx> {
-        let pat = self.tcx.infer_ctxt().enter(|infcx| {
+    ) -> Box<Pat<'tcx>> {
+        self.tcx.infer_ctxt().enter(|infcx| {
             let mut convert = ConstToPat::new(self, id, span, infcx);
             convert.to_pat(cv, mir_structural_match_violation)
-        });
-
-        debug!(?pat);
-        pat
+        })
     }
 }
 
@@ -159,7 +156,7 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
         &mut self,
         cv: mir::ConstantKind<'tcx>,
         mir_structural_match_violation: bool,
-    ) -> Pat<'tcx> {
+    ) -> Box<Pat<'tcx>> {
         trace!(self.treat_byte_string_as_slice);
         // This method is just a wrapper handling a validity check; the heavy lifting is
         // performed by the recursive `recur` method, which is not meant to be
@@ -169,10 +166,12 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
         // level of indirection can be eliminated
 
         let inlined_const_as_pat =
-            self.recur(cv, mir_structural_match_violation).unwrap_or_else(|_| Pat {
-                span: self.span,
-                ty: cv.ty(),
-                kind: Box::new(PatKind::Constant { value: cv }),
+            self.recur(cv, mir_structural_match_violation).unwrap_or_else(|_| {
+                Box::new(Pat {
+                    span: self.span,
+                    ty: cv.ty(),
+                    kind: PatKind::Constant { value: cv },
+                })
             });
 
         if self.include_lint_checks && !self.saw_const_match_error.get() {
@@ -274,7 +273,7 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
         &self,
         cv: mir::ConstantKind<'tcx>,
         mir_structural_match_violation: bool,
-    ) -> Result<Pat<'tcx>, FallbackToConstRef> {
+    ) -> Result<Box<Pat<'tcx>>, FallbackToConstRef> {
         let id = self.id;
         let span = self.span;
         let tcx = self.tcx();
@@ -401,7 +400,7 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
                     .map(|val| self.recur(*val, false))
                     .collect::<Result<_, _>>()?,
                 slice: None,
-                suffix: Vec::new(),
+                suffix: Box::new([]),
             },
             ty::Ref(_, pointee_ty, ..) => match *pointee_ty.kind() {
                 // These are not allowed and will error elsewhere anyway.
@@ -428,8 +427,8 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
                     let old = self.behind_reference.replace(true);
                     let array = tcx.deref_mir_constant(self.param_env.and(cv));
                     let val = PatKind::Deref {
-                        subpattern: Pat {
-                            kind: Box::new(PatKind::Array {
+                        subpattern: Box::new(Pat {
+                            kind: PatKind::Array {
                                 prefix: tcx
                                     .destructure_mir_constant(param_env, array)
                                     .fields
@@ -437,11 +436,11 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
                                     .map(|val| self.recur(*val, false))
                                     .collect::<Result<_, _>>()?,
                                 slice: None,
-                                suffix: vec![],
-                            }),
+                                suffix: Box::new([]),
+                            },
                             span,
                             ty: *pointee_ty,
-                        },
+                        }),
                     };
                     self.behind_reference.set(old);
                     val
@@ -454,8 +453,8 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
                     let old = self.behind_reference.replace(true);
                     let array = tcx.deref_mir_constant(self.param_env.and(cv));
                     let val = PatKind::Deref {
-                        subpattern: Pat {
-                            kind: Box::new(PatKind::Slice {
+                        subpattern: Box::new(Pat {
+                            kind: PatKind::Slice {
                                 prefix: tcx
                                     .destructure_mir_constant(param_env, array)
                                     .fields
@@ -463,11 +462,11 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
                                     .map(|val| self.recur(*val, false))
                                     .collect::<Result<_, _>>()?,
                                 slice: None,
-                                suffix: vec![],
-                            }),
+                                suffix: Box::new([]),
+                            },
                             span,
                             ty: tcx.mk_slice(elem_ty),
-                        },
+                        }),
                     };
                     self.behind_reference.set(old);
                     val
@@ -601,6 +600,6 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
             );
         }
 
-        Ok(Pat { span, ty: cv.ty(), kind: Box::new(kind) })
+        Ok(Box::new(Pat { span, ty: cv.ty(), kind }))
     }
 }
diff --git a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
index 8d6f8efb6003..5105f059f9b6 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
@@ -71,9 +71,9 @@ use std::ops::RangeInclusive;
 /// Recursively expand this pattern into its subpatterns. Only useful for or-patterns.
 fn expand_or_pat<'p, 'tcx>(pat: &'p Pat<'tcx>) -> Vec<&'p Pat<'tcx>> {
     fn expand<'p, 'tcx>(pat: &'p Pat<'tcx>, vec: &mut Vec<&'p Pat<'tcx>>) {
-        if let PatKind::Or { pats } = pat.kind.as_ref() {
-            for pat in pats {
-                expand(pat, vec);
+        if let PatKind::Or { pats } = &pat.kind {
+            for pat in pats.iter() {
+                expand(&pat, vec);
             }
         } else {
             vec.push(pat)
@@ -252,10 +252,14 @@ impl IntRange {
         let kind = if lo == hi {
             PatKind::Constant { value: lo_const }
         } else {
-            PatKind::Range(PatRange { lo: lo_const, hi: hi_const, end: RangeEnd::Included })
+            PatKind::Range(Box::new(PatRange {
+                lo: lo_const,
+                hi: hi_const,
+                end: RangeEnd::Included,
+            }))
         };
 
-        Pat { ty, span: DUMMY_SP, kind: Box::new(kind) }
+        Pat { ty, span: DUMMY_SP, kind }
     }
 
     /// Lint on likely incorrect range patterns (#63987)
@@ -1297,7 +1301,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
         let mkpat = |pat| DeconstructedPat::from_pat(cx, pat);
         let ctor;
         let fields;
-        match pat.kind.as_ref() {
+        match &pat.kind {
             PatKind::AscribeUserType { subpattern, .. } => return mkpat(subpattern),
             PatKind::Binding { subpattern: Some(subpat), .. } => return mkpat(subpat),
             PatKind::Binding { subpattern: None, .. } | PatKind::Wild => {
@@ -1342,9 +1346,9 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                         fields = Fields::singleton(cx, pat);
                     }
                     ty::Adt(adt, _) => {
-                        ctor = match pat.kind.as_ref() {
+                        ctor = match pat.kind {
                             PatKind::Leaf { .. } => Single,
-                            PatKind::Variant { variant_index, .. } => Variant(*variant_index),
+                            PatKind::Variant { variant_index, .. } => Variant(variant_index),
                             _ => bug!(),
                         };
                         let variant = &adt.variant(ctor.variant_index_for_adt(*adt));
@@ -1402,7 +1406,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                     }
                 }
             }
-            &PatKind::Range(PatRange { lo, hi, end }) => {
+            &PatKind::Range(box PatRange { lo, hi, end }) => {
                 let ty = lo.ty();
                 ctor = if let Some(int_range) = IntRange::from_range(
                     cx.tcx,
@@ -1429,7 +1433,8 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                     FixedLen(prefix.len() + suffix.len())
                 };
                 ctor = Slice(Slice::new(array_len, kind));
-                fields = Fields::from_iter(cx, prefix.iter().chain(suffix).map(mkpat));
+                fields =
+                    Fields::from_iter(cx, prefix.iter().chain(suffix.iter()).map(|p| mkpat(&*p)));
             }
             PatKind::Or { .. } => {
                 ctor = Or;
@@ -1442,15 +1447,15 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
 
     pub(crate) fn to_pat(&self, cx: &MatchCheckCtxt<'p, 'tcx>) -> Pat<'tcx> {
         let is_wildcard = |pat: &Pat<'_>| {
-            matches!(*pat.kind, PatKind::Binding { subpattern: None, .. } | PatKind::Wild)
+            matches!(pat.kind, PatKind::Binding { subpattern: None, .. } | PatKind::Wild)
         };
-        let mut subpatterns = self.iter_fields().map(|p| p.to_pat(cx));
-        let pat = match &self.ctor {
+        let mut subpatterns = self.iter_fields().map(|p| Box::new(p.to_pat(cx)));
+        let kind = match &self.ctor {
             Single | Variant(_) => match self.ty.kind() {
                 ty::Tuple(..) => PatKind::Leaf {
                     subpatterns: subpatterns
                         .enumerate()
-                        .map(|(i, p)| FieldPat { field: Field::new(i), pattern: p })
+                        .map(|(i, pattern)| FieldPat { field: Field::new(i), pattern })
                         .collect(),
                 },
                 ty::Adt(adt_def, _) if adt_def.is_box() => {
@@ -1485,7 +1490,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                     FixedLen(_) => PatKind::Slice {
                         prefix: subpatterns.collect(),
                         slice: None,
-                        suffix: vec![],
+                        suffix: Box::new([]),
                     },
                     VarLen(prefix, _) => {
                         let mut subpatterns = subpatterns.peekable();
@@ -1504,14 +1509,18 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
                                 subpatterns.next();
                             }
                         }
-                        let suffix: Vec<_> = subpatterns.collect();
+                        let suffix: Box<[_]> = subpatterns.collect();
                         let wild = Pat::wildcard_from_ty(self.ty);
-                        PatKind::Slice { prefix, slice: Some(wild), suffix }
+                        PatKind::Slice {
+                            prefix: prefix.into_boxed_slice(),
+                            slice: Some(Box::new(wild)),
+                            suffix,
+                        }
                     }
                 }
             }
             &Str(value) => PatKind::Constant { value },
-            &FloatRange(lo, hi, end) => PatKind::Range(PatRange { lo, hi, end }),
+            &FloatRange(lo, hi, end) => PatKind::Range(Box::new(PatRange { lo, hi, end })),
             IntRange(range) => return range.to_pat(cx.tcx, self.ty),
             Wildcard | NonExhaustive => PatKind::Wild,
             Missing { .. } => bug!(
@@ -1523,7 +1532,7 @@ impl<'p, 'tcx> DeconstructedPat<'p, 'tcx> {
             }
         };
 
-        Pat { ty: self.ty, span: DUMMY_SP, kind: Box::new(pat) }
+        Pat { ty: self.ty, span: DUMMY_SP, kind }
     }
 
     pub(super) fn is_or_pat(&self) -> bool {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index a13748a2d474..11645f840c13 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -29,27 +29,27 @@ use rustc_span::{Span, Symbol};
 use std::cmp::Ordering;
 
 #[derive(Clone, Debug)]
-pub(crate) enum PatternError {
+enum PatternError {
     AssocConstInPattern(Span),
     ConstParamInPattern(Span),
     StaticInPattern(Span),
     NonConstPath(Span),
 }
 
-pub(crate) struct PatCtxt<'a, 'tcx> {
-    pub(crate) tcx: TyCtxt<'tcx>,
-    pub(crate) param_env: ty::ParamEnv<'tcx>,
-    pub(crate) typeck_results: &'a ty::TypeckResults<'tcx>,
-    pub(crate) errors: Vec<PatternError>,
+struct PatCtxt<'a, 'tcx> {
+    tcx: TyCtxt<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
+    typeck_results: &'a ty::TypeckResults<'tcx>,
+    errors: Vec<PatternError>,
     include_lint_checks: bool,
 }
 
-pub(crate) fn pat_from_hir<'a, 'tcx>(
+pub(super) fn pat_from_hir<'a, 'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     typeck_results: &'a ty::TypeckResults<'tcx>,
     pat: &'tcx hir::Pat<'tcx>,
-) -> Pat<'tcx> {
+) -> Box<Pat<'tcx>> {
     let mut pcx = PatCtxt::new(tcx, param_env, typeck_results);
     let result = pcx.lower_pattern(pat);
     if !pcx.errors.is_empty() {
@@ -61,7 +61,7 @@ pub(crate) fn pat_from_hir<'a, 'tcx>(
 }
 
 impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
-    pub(crate) fn new(
+    fn new(
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         typeck_results: &'a ty::TypeckResults<'tcx>,
@@ -69,12 +69,12 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         PatCtxt { tcx, param_env, typeck_results, errors: vec![], include_lint_checks: false }
     }
 
-    pub(crate) fn include_lint_checks(&mut self) -> &mut Self {
+    fn include_lint_checks(&mut self) -> &mut Self {
         self.include_lint_checks = true;
         self
     }
 
-    pub(crate) fn lower_pattern(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Pat<'tcx> {
+    fn lower_pattern(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Box<Pat<'tcx>> {
         // When implicit dereferences have been inserted in this pattern, the unadjusted lowered
         // pattern has the type that results *after* dereferencing. For example, in this code:
         //
@@ -97,13 +97,13 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         let unadjusted_pat = self.lower_pattern_unadjusted(pat);
         self.typeck_results.pat_adjustments().get(pat.hir_id).unwrap_or(&vec![]).iter().rev().fold(
             unadjusted_pat,
-            |pat, ref_ty| {
+            |pat: Box<_>, ref_ty| {
                 debug!("{:?}: wrapping pattern with type {:?}", pat, ref_ty);
-                Pat {
+                Box::new(Pat {
                     span: pat.span,
                     ty: *ref_ty,
-                    kind: Box::new(PatKind::Deref { subpattern: pat }),
-                }
+                    kind: PatKind::Deref { subpattern: pat },
+                })
             },
         )
     }
@@ -113,7 +113,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         expr: &'tcx hir::Expr<'tcx>,
     ) -> (PatKind<'tcx>, Option<Ascription<'tcx>>) {
         match self.lower_lit(expr) {
-            PatKind::AscribeUserType { ascription, subpattern: Pat { kind: box kind, .. } } => {
+            PatKind::AscribeUserType { ascription, subpattern: box Pat { kind, .. } } => {
                 (kind, Some(ascription))
             }
             kind => (kind, None),
@@ -134,7 +134,9 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         match (end, cmp) {
             // `x..y` where `x < y`.
             // Non-empty because the range includes at least `x`.
-            (RangeEnd::Excluded, Some(Ordering::Less)) => PatKind::Range(PatRange { lo, hi, end }),
+            (RangeEnd::Excluded, Some(Ordering::Less)) => {
+                PatKind::Range(Box::new(PatRange { lo, hi, end }))
+            }
             // `x..y` where `x >= y`. The range is empty => error.
             (RangeEnd::Excluded, _) => {
                 struct_span_err!(
@@ -149,7 +151,9 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
             // `x..=y` where `x == y`.
             (RangeEnd::Included, Some(Ordering::Equal)) => PatKind::Constant { value: lo },
             // `x..=y` where `x < y`.
-            (RangeEnd::Included, Some(Ordering::Less)) => PatKind::Range(PatRange { lo, hi, end }),
+            (RangeEnd::Included, Some(Ordering::Less)) => {
+                PatKind::Range(Box::new(PatRange { lo, hi, end }))
+            }
             // `x..=y` where `x > y` hence the range is empty => error.
             (RangeEnd::Included, _) => {
                 let mut err = struct_span_err!(
@@ -196,8 +200,10 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         }
     }
 
-    fn lower_pattern_unadjusted(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Pat<'tcx> {
+    #[instrument(skip(self), level = "debug")]
+    fn lower_pattern_unadjusted(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Box<Pat<'tcx>> {
         let mut ty = self.typeck_results.node_type(pat.hir_id);
+        let mut span = pat.span;
 
         let kind = match pat.kind {
             hir::PatKind::Wild => PatKind::Wild,
@@ -228,7 +234,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 // constants somewhere. Have them on the range pattern.
                 for end in &[lo, hi] {
                     if let Some((_, Some(ascription))) = end {
-                        let subpattern = Pat { span: pat.span, ty, kind: Box::new(kind) };
+                        let subpattern = Box::new(Pat { span: pat.span, ty, kind });
                         kind =
                             PatKind::AscribeUserType { ascription: ascription.clone(), subpattern };
                     }
@@ -258,6 +264,10 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
             }
 
             hir::PatKind::Binding(_, id, ident, ref sub) => {
+                if let Some(ident_span) = ident.span.find_ancestor_inside(span) {
+                    span = span.with_hi(ident_span.hi());
+                }
+
                 let bm = *self
                     .typeck_results
                     .pat_binding_modes()
@@ -322,14 +332,14 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
             hir::PatKind::Or(ref pats) => PatKind::Or { pats: self.lower_patterns(pats) },
         };
 
-        Pat { span: pat.span, ty, kind: Box::new(kind) }
+        Box::new(Pat { span, ty, kind })
     }
 
     fn lower_tuple_subpats(
         &mut self,
         pats: &'tcx [hir::Pat<'tcx>],
         expected_len: usize,
-        gap_pos: Option<usize>,
+        gap_pos: hir::DotDotPos,
     ) -> Vec<FieldPat<'tcx>> {
         pats.iter()
             .enumerate_and_adjust(expected_len, gap_pos)
@@ -340,11 +350,14 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
             .collect()
     }
 
-    fn lower_patterns(&mut self, pats: &'tcx [hir::Pat<'tcx>]) -> Vec<Pat<'tcx>> {
+    fn lower_patterns(&mut self, pats: &'tcx [hir::Pat<'tcx>]) -> Box<[Box<Pat<'tcx>>]> {
         pats.iter().map(|p| self.lower_pattern(p)).collect()
     }
 
-    fn lower_opt_pattern(&mut self, pat: &'tcx Option<&'tcx hir::Pat<'tcx>>) -> Option<Pat<'tcx>> {
+    fn lower_opt_pattern(
+        &mut self,
+        pat: &'tcx Option<&'tcx hir::Pat<'tcx>>,
+    ) -> Option<Box<Pat<'tcx>>> {
         pat.as_ref().map(|p| self.lower_pattern(p))
     }
 
@@ -436,12 +449,12 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         if let Some(user_ty) = self.user_substs_applied_to_ty_of_hir_id(hir_id) {
             debug!("lower_variant_or_leaf: kind={:?} user_ty={:?} span={:?}", kind, user_ty, span);
             let annotation = CanonicalUserTypeAnnotation {
-                user_ty,
+                user_ty: Box::new(user_ty),
                 span,
                 inferred_ty: self.typeck_results.node_type(hir_id),
             };
             kind = PatKind::AscribeUserType {
-                subpattern: Pat { span, ty, kind: Box::new(kind) },
+                subpattern: Box::new(Pat { span, ty, kind }),
                 ascription: Ascription { annotation, variance: ty::Variance::Covariant },
             };
         }
@@ -453,11 +466,11 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
     /// it to `const_to_pat`. Any other path (like enum variants without fields)
     /// is converted to the corresponding pattern via `lower_variant_or_leaf`.
     #[instrument(skip(self), level = "debug")]
-    fn lower_path(&mut self, qpath: &hir::QPath<'_>, id: hir::HirId, span: Span) -> Pat<'tcx> {
+    fn lower_path(&mut self, qpath: &hir::QPath<'_>, id: hir::HirId, span: Span) -> Box<Pat<'tcx>> {
         let ty = self.typeck_results.node_type(id);
         let res = self.typeck_results.qpath_res(qpath, id);
 
-        let pat_from_kind = |kind| Pat { span, ty, kind: Box::new(kind) };
+        let pat_from_kind = |kind| Box::new(Pat { span, ty, kind });
 
         let (def_id, is_associated_const) = match res {
             Res::Def(DefKind::Const, def_id) => (def_id, false),
@@ -505,13 +518,13 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 let user_provided_types = self.typeck_results().user_provided_types();
                 if let Some(&user_ty) = user_provided_types.get(id) {
                     let annotation = CanonicalUserTypeAnnotation {
-                        user_ty,
+                        user_ty: Box::new(user_ty),
                         span,
                         inferred_ty: self.typeck_results().node_type(id),
                     };
-                    Pat {
+                    Box::new(Pat {
                         span,
-                        kind: Box::new(PatKind::AscribeUserType {
+                        kind: PatKind::AscribeUserType {
                             subpattern: pattern,
                             ascription: Ascription {
                                 annotation,
@@ -519,9 +532,9 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                                 /// `variance` field documentation for details.
                                 variance: ty::Variance::Contravariant,
                             },
-                        }),
+                        },
                         ty: const_.ty(),
-                    }
+                    })
                 } else {
                     pattern
                 }
@@ -553,23 +566,19 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         let value = value.eval(self.tcx, self.param_env);
 
         match value {
-            mir::ConstantKind::Ty(c) => {
-                match c.kind() {
-                    ConstKind::Param(_) => {
-                        self.errors.push(PatternError::ConstParamInPattern(span));
-                        return PatKind::Wild;
-                    }
-                    ConstKind::Unevaluated(_) => {
-                        // If we land here it means the const can't be evaluated because it's `TooGeneric`.
-                        self.tcx
-                            .sess
-                            .span_err(span, "constant pattern depends on a generic parameter");
-                        return PatKind::Wild;
-                    }
-                    _ => bug!("Expected either ConstKind::Param or ConstKind::Unevaluated"),
+            mir::ConstantKind::Ty(c) => match c.kind() {
+                ConstKind::Param(_) => {
+                    self.errors.push(PatternError::ConstParamInPattern(span));
+                    return PatKind::Wild;
                 }
+                _ => bug!("Expected ConstKind::Param"),
+            },
+            mir::ConstantKind::Val(_, _) => self.const_to_pat(value, id, span, false).kind,
+            mir::ConstantKind::Unevaluated(..) => {
+                // If we land here it means the const can't be evaluated because it's `TooGeneric`.
+                self.tcx.sess.span_err(span, "constant pattern depends on a generic parameter");
+                return PatKind::Wild;
             }
-            mir::ConstantKind::Val(_, _) => *self.const_to_pat(value, id, span, false).kind,
         }
     }
 
@@ -580,7 +589,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
     fn lower_lit(&mut self, expr: &'tcx hir::Expr<'tcx>) -> PatKind<'tcx> {
         let (lit, neg) = match expr.kind {
             hir::ExprKind::Path(ref qpath) => {
-                return *self.lower_path(qpath, expr.hir_id, expr.span).kind;
+                return self.lower_path(qpath, expr.hir_id, expr.span).kind;
             }
             hir::ExprKind::ConstBlock(ref anon_const) => {
                 return self.lower_inline_const(anon_const, expr.hir_id, expr.span);
@@ -598,7 +607,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
         let lit_input =
             LitToConstInput { lit: &lit.node, ty: self.typeck_results.expr_ty(expr), neg };
         match self.tcx.at(expr.span).lit_to_mir_constant(lit_input) {
-            Ok(constant) => *self.const_to_pat(constant, expr.hir_id, lit.span, false).kind,
+            Ok(constant) => self.const_to_pat(constant, expr.hir_id, lit.span, false).kind,
             Err(LitToConstError::Reported) => PatKind::Wild,
             Err(LitToConstError::TypeError) => bug!("lower_lit: had type error"),
         }
@@ -615,7 +624,7 @@ impl<'tcx> UserAnnotatedTyHelpers<'tcx> for PatCtxt<'_, 'tcx> {
     }
 }
 
-pub(crate) trait PatternFoldable<'tcx>: Sized {
+trait PatternFoldable<'tcx>: Sized {
     fn fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
         self.super_fold_with(folder)
     }
@@ -623,7 +632,7 @@ pub(crate) trait PatternFoldable<'tcx>: Sized {
     fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self;
 }
 
-pub(crate) trait PatternFolder<'tcx>: Sized {
+trait PatternFolder<'tcx>: Sized {
     fn fold_pattern(&mut self, pattern: &Pat<'tcx>) -> Pat<'tcx> {
         pattern.super_fold_with(self)
     }
@@ -646,6 +655,12 @@ impl<'tcx, T: PatternFoldable<'tcx>> PatternFoldable<'tcx> for Vec<T> {
     }
 }
 
+impl<'tcx, T: PatternFoldable<'tcx>> PatternFoldable<'tcx> for Box<[T]> {
+    fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
+        self.iter().map(|t| t.fold_with(folder)).collect()
+    }
+}
+
 impl<'tcx, T: PatternFoldable<'tcx>> PatternFoldable<'tcx> for Option<T> {
     fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
         self.as_ref().map(|t| t.fold_with(folder))
@@ -665,7 +680,7 @@ macro_rules! ClonePatternFoldableImpls {
 }
 
 ClonePatternFoldableImpls! { <'tcx>
-    Span, Field, Mutability, Symbol, LocalVarId, usize, ty::Const<'tcx>,
+    Span, Field, Mutability, Symbol, LocalVarId, usize,
     Region<'tcx>, Ty<'tcx>, BindingMode, AdtDef<'tcx>,
     SubstsRef<'tcx>, &'tcx GenericArg<'tcx>, UserType<'tcx>,
     UserTypeProjection, CanonicalUserTypeAnnotation<'tcx>
@@ -732,7 +747,7 @@ impl<'tcx> PatternFoldable<'tcx> for PatKind<'tcx> {
                 PatKind::Deref { subpattern: subpattern.fold_with(folder) }
             }
             PatKind::Constant { value } => PatKind::Constant { value },
-            PatKind::Range(range) => PatKind::Range(range),
+            PatKind::Range(ref range) => PatKind::Range(range.clone()),
             PatKind::Slice { ref prefix, ref slice, ref suffix } => PatKind::Slice {
                 prefix: prefix.fold_with(folder),
                 slice: slice.fold_with(folder),
diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
index 443626d14b9f..02e047afaf31 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
@@ -754,8 +754,8 @@ fn lint_non_exhaustive_omitted_patterns<'p, 'tcx>(
     hir_id: HirId,
     witnesses: Vec<DeconstructedPat<'p, 'tcx>>,
 ) {
-    let joined_patterns = joined_uncovered_patterns(cx, &witnesses);
     cx.tcx.struct_span_lint_hir(NON_EXHAUSTIVE_OMITTED_PATTERNS, hir_id, sp, |build| {
+        let joined_patterns = joined_uncovered_patterns(cx, &witnesses);
         let mut lint = build.build("some variants are not matched explicitly");
         lint.span_label(sp, pattern_not_covered_label(&witnesses, &joined_patterns));
         lint.help(
@@ -791,7 +791,7 @@ fn lint_non_exhaustive_omitted_patterns<'p, 'tcx>(
 /// `is_under_guard` is used to inform if the pattern has a guard. If it
 /// has one it must not be inserted into the matrix. This shouldn't be
 /// relied on for soundness.
-#[instrument(level = "debug", skip(cx, matrix, hir_id))]
+#[instrument(level = "debug", skip(cx, matrix, hir_id), ret)]
 fn is_useful<'p, 'tcx>(
     cx: &MatchCheckCtxt<'p, 'tcx>,
     matrix: &Matrix<'p, 'tcx>,
@@ -842,7 +842,15 @@ fn is_useful<'p, 'tcx>(
             }
         }
     } else {
-        let ty = v.head().ty();
+        let mut ty = v.head().ty();
+
+        // Opaque types can't get destructured/split, but the patterns can
+        // actually hint at hidden types, so we use the patterns' types instead.
+        if let ty::Opaque(..) = ty.kind() {
+            if let Some(row) = rows.first() {
+                ty = row.head().ty();
+            }
+        }
         let is_non_exhaustive = cx.is_foreign_non_exhaustive_enum(ty);
         debug!("v.head: {:?}, v.span: {:?}", v.head(), v.head().span());
         let pcx = &PatCtxt { cx, ty, span: v.head().span(), is_top_level, is_non_exhaustive };
@@ -917,7 +925,6 @@ fn is_useful<'p, 'tcx>(
         v.head().set_reachable();
     }
 
-    debug!(?ret);
     ret
 }
 
diff --git a/compiler/rustc_mir_dataflow/src/elaborate_drops.rs b/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
index c0b0cc3c591b..702ca2eaf5c4 100644
--- a/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
@@ -893,7 +893,7 @@ where
             }
             ty::Slice(ety) => self.open_drop_for_array(*ety, None),
 
-            _ => bug!("open drop from non-ADT `{:?}`", ty),
+            _ => span_bug!(self.source_info.span, "open drop from non-ADT `{:?}`", ty),
         }
     }
 
diff --git a/compiler/rustc_mir_dataflow/src/errors.rs b/compiler/rustc_mir_dataflow/src/errors.rs
index cc14257876c5..5b1a88cb2845 100644
--- a/compiler/rustc_mir_dataflow/src/errors.rs
+++ b/compiler/rustc_mir_dataflow/src/errors.rs
@@ -1,21 +1,21 @@
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::path_must_end_in_filename)]
 pub(crate) struct PathMustEndInFilename {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::unknown_formatter)]
 pub(crate) struct UnknownFormatter {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::duplicate_values_for)]
 pub(crate) struct DuplicateValuesFor {
     #[primary_span]
@@ -23,7 +23,7 @@ pub(crate) struct DuplicateValuesFor {
     pub name: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::requires_an_argument)]
 pub(crate) struct RequiresAnArgument {
     #[primary_span]
@@ -31,39 +31,39 @@ pub(crate) struct RequiresAnArgument {
     pub name: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::stop_after_dataflow_ended_compilation)]
 pub(crate) struct StopAfterDataFlowEndedCompilation;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::peek_must_be_place_or_ref_place)]
 pub(crate) struct PeekMustBePlaceOrRefPlace {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::peek_must_be_not_temporary)]
 pub(crate) struct PeekMustBeNotTemporary {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::peek_bit_not_set)]
 pub(crate) struct PeekBitNotSet {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::peek_argument_not_a_local)]
 pub(crate) struct PeekArgumentNotALocal {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_dataflow::peek_argument_untracked)]
 pub(crate) struct PeekArgumentUntracked {
     #[primary_span]
diff --git a/compiler/rustc_mir_dataflow/src/impls/liveness.rs b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
index 483c1e274aa7..3e08a8799ef9 100644
--- a/compiler/rustc_mir_dataflow/src/impls/liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
@@ -270,7 +270,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
             | StatementKind::Retag(..)
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
-            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Intrinsic(..)
             | StatementKind::Nop => None,
         };
         if let Some(destination) = destination {
diff --git a/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs b/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
index f6b5af90a85c..18760b6c6fa5 100644
--- a/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
@@ -142,7 +142,7 @@ impl<'mir, 'tcx> crate::GenKillAnalysis<'tcx> for MaybeRequiresStorage<'mir, 'tc
             | StatementKind::FakeRead(..)
             | StatementKind::Nop
             | StatementKind::Retag(..)
-            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Intrinsic(..)
             | StatementKind::StorageLive(..) => {}
         }
     }
diff --git a/compiler/rustc_mir_dataflow/src/lib.rs b/compiler/rustc_mir_dataflow/src/lib.rs
index 62b712f7b8db..b471d04fd606 100644
--- a/compiler/rustc_mir_dataflow/src/lib.rs
+++ b/compiler/rustc_mir_dataflow/src/lib.rs
@@ -1,7 +1,6 @@
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(exact_size_is_empty)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(once_cell)]
 #![feature(stmt_expr_attributes)]
diff --git a/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs b/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs
index 28936274baaf..7806e8f45d3a 100644
--- a/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs
+++ b/compiler/rustc_mir_dataflow/src/move_paths/abs_domain.rs
@@ -48,6 +48,7 @@ impl<'tcx> Lift for PlaceElem<'tcx> {
         match *self {
             ProjectionElem::Deref => ProjectionElem::Deref,
             ProjectionElem::Field(f, ty) => ProjectionElem::Field(f, ty.lift()),
+            ProjectionElem::OpaqueCast(ty) => ProjectionElem::OpaqueCast(ty.lift()),
             ProjectionElem::Index(ref i) => ProjectionElem::Index(i.lift()),
             ProjectionElem::Subslice { from, to, from_end } => {
                 ProjectionElem::Subslice { from, to, from_end }
diff --git a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
index c32583862239..f46fd118bde5 100644
--- a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
+++ b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
@@ -330,7 +330,7 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
             StatementKind::Retag { .. }
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
-            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Intrinsic(..)
             | StatementKind::Nop => {}
         }
     }
diff --git a/compiler/rustc_mir_transform/src/check_unsafety.rs b/compiler/rustc_mir_transform/src/check_unsafety.rs
index 0f5fd77f7ab1..beff19a3ab2e 100644
--- a/compiler/rustc_mir_transform/src/check_unsafety.rs
+++ b/compiler/rustc_mir_transform/src/check_unsafety.rs
@@ -105,7 +105,8 @@ impl<'tcx> Visitor<'tcx> for UnsafetyChecker<'_, 'tcx> {
                 // safe (at least as emitted during MIR construction)
             }
 
-            StatementKind::CopyNonOverlapping(..) => unreachable!(),
+            // Move to above list once mir construction uses it.
+            StatementKind::Intrinsic(..) => unreachable!(),
         }
         self.super_statement(statement, location);
     }
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 53f33a7a0bad..4a9bd9df327f 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -17,7 +17,7 @@ use rustc_middle::mir::{
     RETURN_PLACE,
 };
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
+use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, ConstKind, Instance, ParamEnv, Ty, TyCtxt, TypeVisitable};
 use rustc_span::{def_id::DefId, Span};
 use rustc_target::abi::{self, HasDataLayout, Size, TargetDataLayout};
@@ -471,7 +471,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        self.ecx.mir_const_to_op(&c.literal, None).ok()
+        self.ecx.const_to_op(&c.literal, None).ok()
     }
 
     /// Returns the value, if any, of evaluating `place`.
@@ -1066,32 +1066,32 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> {
         let source_info = terminator.source_info;
         self.source_info = Some(source_info);
         self.super_terminator(terminator, location);
+        // Do NOT early return in this function, it does some crucial fixup of the state at the end!
         match &mut terminator.kind {
             TerminatorKind::Assert { expected, ref mut cond, .. } => {
                 if let Some(ref value) = self.eval_operand(&cond) {
                     trace!("assertion on {:?} should be {:?}", value, expected);
                     let expected = Scalar::from_bool(*expected);
-                    let Ok(value_const) = self.ecx.read_scalar(&value) else {
-                        // FIXME should be used use_ecx rather than a local match... but we have
-                        // quite a few of these read_scalar/read_immediate that need fixing.
-                        return
-                    };
-                    if expected != value_const {
-                        // Poison all places this operand references so that further code
-                        // doesn't use the invalid value
-                        match cond {
-                            Operand::Move(ref place) | Operand::Copy(ref place) => {
-                                Self::remove_const(&mut self.ecx, place.local);
+                    // FIXME should be used use_ecx rather than a local match... but we have
+                    // quite a few of these read_scalar/read_immediate that need fixing.
+                    if let Ok(value_const) = self.ecx.read_scalar(&value) {
+                        if expected != value_const {
+                            // Poison all places this operand references so that further code
+                            // doesn't use the invalid value
+                            match cond {
+                                Operand::Move(ref place) | Operand::Copy(ref place) => {
+                                    Self::remove_const(&mut self.ecx, place.local);
+                                }
+                                Operand::Constant(_) => {}
+                            }
+                        } else {
+                            if self.should_const_prop(value) {
+                                *cond = self.operand_from_scalar(
+                                    value_const,
+                                    self.tcx.types.bool,
+                                    source_info.span,
+                                );
                             }
-                            Operand::Constant(_) => {}
-                        }
-                    } else {
-                        if self.should_const_prop(value) {
-                            *cond = self.operand_from_scalar(
-                                value_const,
-                                self.tcx.types.bool,
-                                source_info.span,
-                            );
                         }
                     }
                 }
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 082d6c9f07e5..973f55437eeb 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -16,15 +16,13 @@ use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{
-    AssertKind, BinOp, Body, Constant, ConstantKind, Local, LocalDecl, Location, Operand, Place,
-    Rvalue, SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator,
+    self, AssertKind, BinOp, Body, Constant, ConstantKind, Local, LocalDecl, Location, Operand,
+    Place, Rvalue, SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator,
     TerminatorKind, UnOp, RETURN_PLACE,
 };
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
-use rustc_middle::ty::{
-    self, ConstInt, ConstKind, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeVisitable,
-};
+use rustc_middle::ty::InternalSubsts;
+use rustc_middle::ty::{self, ConstInt, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeVisitable};
 use rustc_session::lint;
 use rustc_span::Span;
 use rustc_target::abi::{HasDataLayout, Size, TargetDataLayout};
@@ -294,25 +292,22 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        match self.ecx.mir_const_to_op(&c.literal, None) {
+        match self.ecx.const_to_op(&c.literal, None) {
             Ok(op) => Some(op),
             Err(error) => {
                 let tcx = self.ecx.tcx.at(c.span);
                 let err = ConstEvalErr::new(&self.ecx, error, Some(c.span));
                 if let Some(lint_root) = self.lint_root(source_info) {
                     let lint_only = match c.literal {
-                        ConstantKind::Ty(ct) => match ct.kind() {
+                        ConstantKind::Ty(ct) => ct.needs_subst(),
+                        ConstantKind::Unevaluated(
+                            mir::UnevaluatedConst { def: _, substs: _, promoted: Some(_) },
+                            _,
+                        ) => {
                             // Promoteds must lint and not error as the user didn't ask for them
-                            ConstKind::Unevaluated(ty::Unevaluated {
-                                def: _,
-                                substs: _,
-                                promoted: Some(_),
-                            }) => true,
-                            // Out of backwards compatibility we cannot report hard errors in unused
-                            // generic functions using associated constants of the generic parameters.
-                            _ => c.literal.needs_subst(),
-                        },
-                        ConstantKind::Val(_, ty) => ty.needs_subst(),
+                            true
+                        }
+                        ConstantKind::Unevaluated(..) | ConstantKind::Val(..) => c.needs_subst(),
                     };
                     if lint_only {
                         // Out of backwards compatibility we cannot report hard errors in unused
diff --git a/compiler/rustc_mir_transform/src/coverage/spans.rs b/compiler/rustc_mir_transform/src/coverage/spans.rs
index 423e78317aad..9f842c929dc2 100644
--- a/compiler/rustc_mir_transform/src/coverage/spans.rs
+++ b/compiler/rustc_mir_transform/src/coverage/spans.rs
@@ -825,7 +825,7 @@ pub(super) fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span>
 
         // Retain spans from all other statements
         StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding`
-        | StatementKind::CopyNonOverlapping(..)
+        | StatementKind::Intrinsic(..)
         | StatementKind::Assign(_)
         | StatementKind::SetDiscriminant { .. }
         | StatementKind::Deinit(..)
diff --git a/compiler/rustc_mir_transform/src/dead_store_elimination.rs b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
index 9163672f5703..3f3870cc7bad 100644
--- a/compiler/rustc_mir_transform/src/dead_store_elimination.rs
+++ b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
@@ -52,7 +52,7 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS
                 | StatementKind::StorageLive(_)
                 | StatementKind::StorageDead(_)
                 | StatementKind::Coverage(_)
-                | StatementKind::CopyNonOverlapping(_)
+                | StatementKind::Intrinsic(_)
                 | StatementKind::Nop => (),
 
                 StatementKind::FakeRead(_) | StatementKind::AscribeUserType(_, _) => {
diff --git a/compiler/rustc_mir_transform/src/dest_prop.rs b/compiler/rustc_mir_transform/src/dest_prop.rs
index da55510920e1..9bc47613e4c6 100644
--- a/compiler/rustc_mir_transform/src/dest_prop.rs
+++ b/compiler/rustc_mir_transform/src/dest_prop.rs
@@ -537,7 +537,7 @@ impl<'a> Conflicts<'a> {
             | StatementKind::FakeRead(..)
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
-            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Intrinsic(..)
             | StatementKind::Nop => {}
         }
     }
diff --git a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
index 294af2455d06..ef8d6bb65590 100644
--- a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
@@ -8,7 +8,6 @@ use rustc_index::vec::Idx;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{Ty, TyCtxt};
 
 /// Constructs the types used when accessing a Box's pointer
diff --git a/compiler/rustc_mir_transform/src/function_item_references.rs b/compiler/rustc_mir_transform/src/function_item_references.rs
index 2e4fe1e3e5dd..0568eb2ffa60 100644
--- a/compiler/rustc_mir_transform/src/function_item_references.rs
+++ b/compiler/rustc_mir_transform/src/function_item_references.rs
@@ -3,11 +3,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::*;
-use rustc_middle::ty::{
-    self,
-    subst::{GenericArgKind, Subst, SubstsRef},
-    EarlyBinder, PredicateKind, Ty, TyCtxt,
-};
+use rustc_middle::ty::{self, EarlyBinder, GenericArgKind, PredicateKind, SubstsRef, Ty, TyCtxt};
 use rustc_session::lint::builtin::FUNCTION_ITEM_REFERENCES;
 use rustc_span::{symbol::sym, Span};
 use rustc_target::spec::abi::Abi;
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index dbff4a6bd696..c833de3a8a75 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -61,9 +61,8 @@ use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::mir::dump_mir;
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::ty::subst::{Subst, SubstsRef};
-use rustc_middle::ty::GeneratorSubsts;
 use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
+use rustc_middle::ty::{GeneratorSubsts, SubstsRef};
 use rustc_mir_dataflow::impls::{
     MaybeBorrowedLocals, MaybeLiveLocals, MaybeRequiresStorage, MaybeStorageLive,
 };
@@ -1452,7 +1451,7 @@ impl<'tcx> Visitor<'tcx> for EnsureGeneratorFieldAssignmentsNeverAlias<'_> {
             | StatementKind::Retag(..)
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
-            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Intrinsic(..)
             | StatementKind::Nop => {}
         }
     }
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index ba00f16308ea..852557ba7969 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -7,8 +7,7 @@ use rustc_index::vec::Idx;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
-use rustc_middle::ty::subst::Subst;
-use rustc_middle::ty::{self, ConstKind, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
+use rustc_middle::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
 use rustc_session::config::OptLevel;
 use rustc_span::def_id::DefId;
 use rustc_span::{hygiene::ExpnKind, ExpnData, LocalExpnId, Span};
@@ -604,11 +603,11 @@ impl<'tcx> Inliner<'tcx> {
                 // `required_consts`, here we may not only have `ConstKind::Unevaluated`
                 // because we are calling `subst_and_normalize_erasing_regions`.
                 caller_body.required_consts.extend(
-                    callee_body.required_consts.iter().copied().filter(|&ct| {
-                        match ct.literal.const_for_ty() {
-                            Some(ct) => matches!(ct.kind(), ConstKind::Unevaluated(_)),
-                            None => true,
+                    callee_body.required_consts.iter().copied().filter(|&ct| match ct.literal {
+                        ConstantKind::Ty(_) => {
+                            bug!("should never encounter ty::UnevaluatedConst in `required_consts`")
                         }
+                        ConstantKind::Val(..) | ConstantKind::Unevaluated(..) => true,
                     }),
                 );
             }
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 0b674b38f328..2230c3399f0f 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -1,7 +1,6 @@
 #![allow(rustc::potential_query_instability)]
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(never_type)]
@@ -10,6 +9,7 @@
 #![feature(trusted_step)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
+#![feature(if_let_guard)]
 #![recursion_limit = "256"]
 
 #[macro_use]
@@ -27,10 +27,13 @@ use rustc_hir::intravisit::{self, Visitor};
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir::visit::Visitor as _;
 use rustc_middle::mir::{
-    traversal, AnalysisPhase, Body, ConstQualifs, MirPass, MirPhase, Promoted, RuntimePhase,
+    traversal, AnalysisPhase, Body, ConstQualifs, Constant, LocalDecl, MirPass, MirPhase, Operand,
+    Place, ProjectionElem, Promoted, RuntimePhase, Rvalue, SourceInfo, Statement, StatementKind,
+    TerminatorKind,
 };
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, TypeVisitable};
+use rustc_span::sym;
 
 #[macro_use]
 mod pass_manager;
@@ -140,6 +143,64 @@ pub fn provide(providers: &mut Providers) {
     };
 }
 
+fn remap_mir_for_const_eval_select<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    mut body: Body<'tcx>,
+    context: hir::Constness,
+) -> Body<'tcx> {
+    for bb in body.basic_blocks.as_mut().iter_mut() {
+        let terminator = bb.terminator.as_mut().expect("invalid terminator");
+        match terminator.kind {
+            TerminatorKind::Call {
+                func: Operand::Constant(box Constant { ref literal, .. }),
+                ref mut args,
+                destination,
+                target,
+                cleanup,
+                fn_span,
+                ..
+            } if let ty::FnDef(def_id, _) = *literal.ty().kind()
+                && tcx.item_name(def_id) == sym::const_eval_select
+                && tcx.is_intrinsic(def_id) =>
+            {
+                let [tupled_args, called_in_const, called_at_rt]: [_; 3] = std::mem::take(args).try_into().unwrap();
+                let ty = tupled_args.ty(&body.local_decls, tcx);
+                let fields = ty.tuple_fields();
+                let num_args = fields.len();
+                let func = if context == hir::Constness::Const { called_in_const } else { called_at_rt };
+                let (method, place): (fn(Place<'tcx>) -> Operand<'tcx>, Place<'tcx>) = match tupled_args {
+                    Operand::Constant(_) => {
+                        // there is no good way of extracting a tuple arg from a constant (const generic stuff)
+                        // so we just create a temporary and deconstruct that.
+                        let local = body.local_decls.push(LocalDecl::new(ty, fn_span));
+                        bb.statements.push(Statement {
+                            source_info: SourceInfo::outermost(fn_span),
+                            kind: StatementKind::Assign(Box::new((local.into(), Rvalue::Use(tupled_args.clone())))),
+                        });
+                        (Operand::Move, local.into())
+                    }
+                    Operand::Move(place) => (Operand::Move, place),
+                    Operand::Copy(place) => (Operand::Copy, place),
+                };
+                let place_elems = place.projection;
+                let arguments = (0..num_args).map(|x| {
+                    let mut place_elems = place_elems.to_vec();
+                    place_elems.push(ProjectionElem::Field(x.into(), fields[x]));
+                    let projection = tcx.intern_place_elems(&place_elems);
+                    let place = Place {
+                        local: place.local,
+                        projection,
+                    };
+                    method(place)
+                }).collect();
+                terminator.kind = TerminatorKind::Call { func, args: arguments, destination, target, cleanup, from_hir_call: false, fn_span };
+            }
+            _ => {}
+        }
+    }
+    body
+}
+
 fn is_mir_available(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     let def_id = def_id.expect_local();
     tcx.mir_keys(()).contains(&def_id)
@@ -325,7 +386,9 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -
         .body_const_context(def.did)
         .expect("mir_for_ctfe should not be used for runtime functions");
 
-    let mut body = tcx.mir_drops_elaborated_and_const_checked(def).borrow().clone();
+    let body = tcx.mir_drops_elaborated_and_const_checked(def).borrow().clone();
+
+    let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::Const);
 
     match context {
         // Do not const prop functions, either they get executed at runtime or exported to metadata,
@@ -558,8 +621,9 @@ fn inner_optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> Body<'_> {
         Some(other) => panic!("do not use `optimized_mir` for constants: {:?}", other),
     }
     debug!("about to call mir_drops_elaborated...");
-    let mut body =
+    let body =
         tcx.mir_drops_elaborated_and_const_checked(ty::WithOptConstParam::unknown(did)).steal();
+    let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::NotConst);
     debug!("body: {:#?}", body);
     run_optimization_passes(tcx, &mut body);
 
diff --git a/compiler/rustc_mir_transform/src/lower_intrinsics.rs b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
index b7ba616510c2..9892580e63dc 100644
--- a/compiler/rustc_mir_transform/src/lower_intrinsics.rs
+++ b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
@@ -46,12 +46,31 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
                         let mut args = args.drain(..);
                         block.statements.push(Statement {
                             source_info: terminator.source_info,
-                            kind: StatementKind::CopyNonOverlapping(Box::new(
-                                rustc_middle::mir::CopyNonOverlapping {
-                                    src: args.next().unwrap(),
-                                    dst: args.next().unwrap(),
-                                    count: args.next().unwrap(),
-                                },
+                            kind: StatementKind::Intrinsic(Box::new(
+                                NonDivergingIntrinsic::CopyNonOverlapping(
+                                    rustc_middle::mir::CopyNonOverlapping {
+                                        src: args.next().unwrap(),
+                                        dst: args.next().unwrap(),
+                                        count: args.next().unwrap(),
+                                    },
+                                ),
+                            )),
+                        });
+                        assert_eq!(
+                            args.next(),
+                            None,
+                            "Extra argument for copy_non_overlapping intrinsic"
+                        );
+                        drop(args);
+                        terminator.kind = TerminatorKind::Goto { target };
+                    }
+                    sym::assume => {
+                        let target = target.unwrap();
+                        let mut args = args.drain(..);
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::Intrinsic(Box::new(
+                                NonDivergingIntrinsic::Assume(args.next().unwrap()),
                             )),
                         });
                         assert_eq!(
diff --git a/compiler/rustc_mir_transform/src/pass_manager.rs b/compiler/rustc_mir_transform/src/pass_manager.rs
index 67ea5cfdb3c0..67dae71468f9 100644
--- a/compiler/rustc_mir_transform/src/pass_manager.rs
+++ b/compiler/rustc_mir_transform/src/pass_manager.rs
@@ -103,7 +103,7 @@ fn run_passes_inner<'tcx>(
         let name = pass.name();
 
         // Gather information about what we should be doing for this pass
-        let overriden =
+        let overridden =
             overridden_passes.iter().rev().find(|(s, _)| s == &*name).map(|(_name, polarity)| {
                 trace!(
                     pass = %name,
@@ -112,7 +112,7 @@ fn run_passes_inner<'tcx>(
                 );
                 *polarity
             });
-        let is_enabled = overriden.unwrap_or_else(|| pass.is_enabled(&tcx.sess));
+        let is_enabled = overridden.unwrap_or_else(|| pass.is_enabled(&tcx.sess));
         let new_phase = pass.phase_change();
         let dump_enabled = (is_enabled && pass.is_mir_dump_enabled()) || new_phase.is_some();
         let validate = (validate && is_enabled)
diff --git a/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs b/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
index 41a0bfac41ae..f1bbf2ea7e8e 100644
--- a/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
+++ b/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
@@ -51,7 +51,7 @@ impl RemoveNoopLandingPads {
                 StatementKind::Assign { .. }
                 | StatementKind::SetDiscriminant { .. }
                 | StatementKind::Deinit(..)
-                | StatementKind::CopyNonOverlapping(..)
+                | StatementKind::Intrinsic(..)
                 | StatementKind::Retag { .. } => {
                     return false;
                 }
diff --git a/compiler/rustc_mir_transform/src/required_consts.rs b/compiler/rustc_mir_transform/src/required_consts.rs
index 827ce0c02ac4..cc75947d9dda 100644
--- a/compiler/rustc_mir_transform/src/required_consts.rs
+++ b/compiler/rustc_mir_transform/src/required_consts.rs
@@ -1,5 +1,5 @@
 use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{Constant, Location};
+use rustc_middle::mir::{Constant, ConstantKind, Location};
 use rustc_middle::ty::ConstKind;
 
 pub struct RequiredConstsVisitor<'a, 'tcx> {
@@ -15,8 +15,13 @@ impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
 impl<'tcx> Visitor<'tcx> for RequiredConstsVisitor<'_, 'tcx> {
     fn visit_constant(&mut self, constant: &Constant<'tcx>, _: Location) {
         let literal = constant.literal;
-        if let Some(ct) = literal.const_for_ty() && let ConstKind::Unevaluated(_) = ct.kind() {
-            self.required_consts.push(*constant);
+        match literal {
+            ConstantKind::Ty(c) => match c.kind() {
+                ConstKind::Param(_) => {}
+                _ => bug!("only ConstKind::Param should be encountered here, got {:#?}", c),
+            },
+            ConstantKind::Unevaluated(..) => self.required_consts.push(*constant),
+            ConstantKind::Val(..) => {}
         }
     }
 }
diff --git a/compiler/rustc_mir_transform/src/separate_const_switch.rs b/compiler/rustc_mir_transform/src/separate_const_switch.rs
index 190f9c1ac158..2f116aaa9584 100644
--- a/compiler/rustc_mir_transform/src/separate_const_switch.rs
+++ b/compiler/rustc_mir_transform/src/separate_const_switch.rs
@@ -249,7 +249,7 @@ fn is_likely_const<'tcx>(mut tracked_place: Place<'tcx>, block: &BasicBlockData<
             | StatementKind::AscribeUserType(_, _)
             | StatementKind::Coverage(_)
             | StatementKind::StorageDead(_)
-            | StatementKind::CopyNonOverlapping(_)
+            | StatementKind::Intrinsic(_)
             | StatementKind::Nop => {}
         }
     }
@@ -317,7 +317,7 @@ fn find_determining_place<'tcx>(
             | StatementKind::Retag(_, _)
             | StatementKind::AscribeUserType(_, _)
             | StatementKind::Coverage(_)
-            | StatementKind::CopyNonOverlapping(_)
+            | StatementKind::Intrinsic(_)
             | StatementKind::Nop => {}
 
             // If the discriminant is set, it is always set
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index 2b21fbe0a617..6ca58ee458c5 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -3,8 +3,8 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::mir::*;
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
-use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt};
+use rustc_middle::ty::InternalSubsts;
+use rustc_middle::ty::{self, EarlyBinder, GeneratorSubsts, Ty, TyCtxt};
 use rustc_target::abi::VariantIdx;
 
 use rustc_index::vec::{Idx, IndexVec};
@@ -323,6 +323,9 @@ fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -
             builder.tuple_like_shim(dest, src, substs.as_closure().upvar_tys())
         }
         ty::Tuple(..) => builder.tuple_like_shim(dest, src, self_ty.tuple_fields()),
+        ty::Generator(gen_def_id, substs, hir::Movability::Movable) => {
+            builder.generator_shim(dest, src, *gen_def_id, substs.as_generator())
+        }
         _ => bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty),
     };
 
@@ -388,7 +391,7 @@ impl<'tcx> CloneShimBuilder<'tcx> {
     /// offset=0 will give you the index of the next BasicBlock,
     /// offset=1 will give the index of the next-to-next block,
     /// offset=-1 will give you the index of the last-created block
-    fn block_index_offset(&mut self, offset: usize) -> BasicBlock {
+    fn block_index_offset(&self, offset: usize) -> BasicBlock {
         BasicBlock::new(self.blocks.len() + offset)
     }
 
@@ -461,49 +464,106 @@ impl<'tcx> CloneShimBuilder<'tcx> {
         );
     }
 
-    fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, src: Place<'tcx>, tys: I)
+    fn clone_fields<I>(
+        &mut self,
+        dest: Place<'tcx>,
+        src: Place<'tcx>,
+        target: BasicBlock,
+        mut unwind: BasicBlock,
+        tys: I,
+    ) -> BasicBlock
     where
         I: IntoIterator<Item = Ty<'tcx>>,
     {
-        let mut previous_field = None;
+        // For an iterator of length n, create 2*n + 1 blocks.
         for (i, ity) in tys.into_iter().enumerate() {
+            // Each iteration creates two blocks, referred to here as block 2*i and block 2*i + 1.
+            //
+            // Block 2*i attempts to clone the field. If successful it branches to 2*i + 2 (the
+            // next clone block). If unsuccessful it branches to the previous unwind block, which
+            // is initially the `unwind` argument passed to this function.
+            //
+            // Block 2*i + 1 is the unwind block for this iteration. It drops the cloned value
+            // created by block 2*i. We store this block in `unwind` so that the next clone block
+            // will unwind to it if cloning fails.
+
             let field = Field::new(i);
             let src_field = self.tcx.mk_place_field(src, field, ity);
 
             let dest_field = self.tcx.mk_place_field(dest, field, ity);
 
-            // #(2i + 1) is the cleanup block for the previous clone operation
-            let cleanup_block = self.block_index_offset(1);
-            // #(2i + 2) is the next cloning block
-            // (or the Return terminator if this is the last block)
+            let next_unwind = self.block_index_offset(1);
             let next_block = self.block_index_offset(2);
-
-            // BB #(2i)
-            // `dest.i = Clone::clone(&src.i);`
-            // Goto #(2i + 2) if ok, #(2i + 1) if unwinding happens.
-            self.make_clone_call(dest_field, src_field, ity, next_block, cleanup_block);
-
-            // BB #(2i + 1) (cleanup)
-            if let Some((previous_field, previous_cleanup)) = previous_field.take() {
-                // Drop previous field and goto previous cleanup block.
-                self.block(
-                    vec![],
-                    TerminatorKind::Drop {
-                        place: previous_field,
-                        target: previous_cleanup,
-                        unwind: None,
-                    },
-                    true,
-                );
-            } else {
-                // Nothing to drop, just resume.
-                self.block(vec![], TerminatorKind::Resume, true);
-            }
-
-            previous_field = Some((dest_field, cleanup_block));
+            self.make_clone_call(dest_field, src_field, ity, next_block, unwind);
+            self.block(
+                vec![],
+                TerminatorKind::Drop { place: dest_field, target: unwind, unwind: None },
+                true,
+            );
+            unwind = next_unwind;
         }
+        // If all clones succeed then we end up here.
+        self.block(vec![], TerminatorKind::Goto { target }, false);
+        unwind
+    }
 
-        self.block(vec![], TerminatorKind::Return, false);
+    fn tuple_like_shim<I>(&mut self, dest: Place<'tcx>, src: Place<'tcx>, tys: I)
+    where
+        I: IntoIterator<Item = Ty<'tcx>>,
+    {
+        self.block(vec![], TerminatorKind::Goto { target: self.block_index_offset(3) }, false);
+        let unwind = self.block(vec![], TerminatorKind::Resume, true);
+        let target = self.block(vec![], TerminatorKind::Return, false);
+
+        let _final_cleanup_block = self.clone_fields(dest, src, target, unwind, tys);
+    }
+
+    fn generator_shim(
+        &mut self,
+        dest: Place<'tcx>,
+        src: Place<'tcx>,
+        gen_def_id: DefId,
+        substs: GeneratorSubsts<'tcx>,
+    ) {
+        self.block(vec![], TerminatorKind::Goto { target: self.block_index_offset(3) }, false);
+        let unwind = self.block(vec![], TerminatorKind::Resume, true);
+        // This will get overwritten with a switch once we know the target blocks
+        let switch = self.block(vec![], TerminatorKind::Unreachable, false);
+        let unwind = self.clone_fields(dest, src, switch, unwind, substs.upvar_tys());
+        let target = self.block(vec![], TerminatorKind::Return, false);
+        let unreachable = self.block(vec![], TerminatorKind::Unreachable, false);
+        let mut cases = Vec::with_capacity(substs.state_tys(gen_def_id, self.tcx).count());
+        for (index, state_tys) in substs.state_tys(gen_def_id, self.tcx).enumerate() {
+            let variant_index = VariantIdx::new(index);
+            let dest = self.tcx.mk_place_downcast_unnamed(dest, variant_index);
+            let src = self.tcx.mk_place_downcast_unnamed(src, variant_index);
+            let clone_block = self.block_index_offset(1);
+            let start_block = self.block(
+                vec![self.make_statement(StatementKind::SetDiscriminant {
+                    place: Box::new(Place::return_place()),
+                    variant_index,
+                })],
+                TerminatorKind::Goto { target: clone_block },
+                false,
+            );
+            cases.push((index as u128, start_block));
+            let _final_cleanup_block = self.clone_fields(dest, src, target, unwind, state_tys);
+        }
+        let discr_ty = substs.discr_ty(self.tcx);
+        let temp = self.make_place(Mutability::Mut, discr_ty);
+        let rvalue = Rvalue::Discriminant(src);
+        let statement = self.make_statement(StatementKind::Assign(Box::new((temp, rvalue))));
+        match &mut self.blocks[switch] {
+            BasicBlockData { statements, terminator: Some(Terminator { kind, .. }), .. } => {
+                statements.push(statement);
+                *kind = TerminatorKind::SwitchInt {
+                    discr: Operand::Move(temp),
+                    switch_ty: discr_ty,
+                    targets: SwitchTargets::new(cases.into_iter(), unreachable),
+                };
+            }
+            BasicBlockData { terminator: None, .. } => unreachable!(),
+        }
     }
 }
 
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index bed48db959a5..57d372fda569 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -499,7 +499,7 @@ impl UsedLocals {
 impl<'tcx> Visitor<'tcx> for UsedLocals {
     fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
         match statement.kind {
-            StatementKind::CopyNonOverlapping(..)
+            StatementKind::Intrinsic(..)
             | StatementKind::Retag(..)
             | StatementKind::Coverage(..)
             | StatementKind::FakeRead(..)
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 170616d4b42c..5cd7a7f760f5 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -112,12 +112,6 @@
 //! method in operand position, we treat it as a neighbor of the current
 //! mono item. Calls are just a special case of that.
 //!
-//! #### Closures
-//! In a way, closures are a simple case. Since every closure object needs to be
-//! constructed somewhere, we can reliably discover them by observing
-//! `RValue::Aggregate` expressions with `AggregateKind::Closure`. This is also
-//! true for closures inlined from other crates.
-//!
 //! #### Drop glue
 //! Drop glue mono items are introduced by MIR drop-statements. The
 //! generated mono item will again have drop-glue item neighbors if the
@@ -419,7 +413,6 @@ fn collect_items_rec<'tcx>(
         // We've been here already, no need to search again.
         return;
     }
-    debug!("BEGIN collect_items_rec({})", starting_point.node);
 
     let mut neighbors = MonoItems { compute_inlining: true, tcx, items: Vec::new() };
     let recursion_depth_reset;
@@ -545,8 +538,6 @@ fn collect_items_rec<'tcx>(
     if let Some((def_id, depth)) = recursion_depth_reset {
         recursion_depths.insert(def_id, depth);
     }
-
-    debug!("END collect_items_rec({})", starting_point.node);
 }
 
 /// Format instance name that is already known to be too long for rustc.
@@ -698,7 +689,8 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 mir::CastKind::Pointer(PointerCast::Unsize),
                 ref operand,
                 target_ty,
-            ) => {
+            )
+            | mir::Rvalue::Cast(mir::CastKind::DynStar, ref operand, target_ty) => {
                 let target_ty = self.monomorphize(target_ty);
                 let source_ty = operand.ty(self.body, self.tcx);
                 let source_ty = self.monomorphize(source_ty);
@@ -707,7 +699,9 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 // This could also be a different Unsize instruction, like
                 // from a fixed sized array to a slice. But we are only
                 // interested in things that produce a vtable.
-                if target_ty.is_trait() && !source_ty.is_trait() {
+                if (target_ty.is_trait() && !source_ty.is_trait())
+                    || (target_ty.is_dyn_star() && !source_ty.is_dyn_star())
+                {
                     create_mono_items_for_vtable_methods(
                         self.tcx,
                         target_ty,
@@ -776,7 +770,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 ty::ConstKind::Unevaluated(ct) => {
                     debug!(?ct);
                     let param_env = ty::ParamEnv::reveal_all();
-                    match self.tcx.const_eval_resolve(param_env, ct, None) {
+                    match self.tcx.const_eval_resolve(param_env, ct.expand(), None) {
                         // The `monomorphize` call should have evaluated that constant already.
                         Ok(val) => val,
                         Err(ErrorHandled::Reported(_) | ErrorHandled::Linted) => return,
@@ -789,44 +783,22 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                 }
                 _ => return,
             },
-        };
-        collect_const_value(self.tcx, val, self.output);
-        self.visit_ty(literal.ty(), TyContext::Location(location));
-    }
-
-    #[instrument(skip(self), level = "debug")]
-    fn visit_const(&mut self, constant: ty::Const<'tcx>, location: Location) {
-        debug!("visiting const {:?} @ {:?}", constant, location);
-
-        let substituted_constant = self.monomorphize(constant);
-        let param_env = ty::ParamEnv::reveal_all();
-
-        match substituted_constant.kind() {
-            ty::ConstKind::Value(val) => {
-                let const_val = self.tcx.valtree_to_const_val((constant.ty(), val));
-                collect_const_value(self.tcx, const_val, self.output)
-            }
-            ty::ConstKind::Unevaluated(unevaluated) => {
-                match self.tcx.const_eval_resolve(param_env, unevaluated, None) {
+            mir::ConstantKind::Unevaluated(uv, _) => {
+                let param_env = ty::ParamEnv::reveal_all();
+                match self.tcx.const_eval_resolve(param_env, uv, None) {
                     // The `monomorphize` call should have evaluated that constant already.
-                    Ok(val) => span_bug!(
-                        self.body.source_info(location).span,
-                        "collection encountered the unevaluated constant {} which evaluated to {:?}",
-                        substituted_constant,
-                        val
-                    ),
-                    Err(ErrorHandled::Reported(_) | ErrorHandled::Linted) => {}
+                    Ok(val) => val,
+                    Err(ErrorHandled::Reported(_) | ErrorHandled::Linted) => return,
                     Err(ErrorHandled::TooGeneric) => span_bug!(
                         self.body.source_info(location).span,
-                        "collection encountered polymorphic constant: {}",
-                        substituted_constant
+                        "collection encountered polymorphic constant: {:?}",
+                        literal
                     ),
                 }
             }
-            _ => {}
-        }
-
-        self.super_const(constant);
+        };
+        collect_const_value(self.tcx, val, self.output);
+        MirVisitor::visit_ty(self, literal.ty(), TyContext::Location(location));
     }
 
     fn visit_terminator(&mut self, terminator: &mir::Terminator<'tcx>, location: Location) {
@@ -838,7 +810,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
             mir::TerminatorKind::Call { ref func, .. } => {
                 let callee_ty = func.ty(self.body, tcx);
                 let callee_ty = self.monomorphize(callee_ty);
-                visit_fn_use(self.tcx, callee_ty, true, source, &mut self.output);
+                visit_fn_use(self.tcx, callee_ty, true, source, &mut self.output)
             }
             mir::TerminatorKind::Drop { ref place, .. }
             | mir::TerminatorKind::DropAndReplace { ref place, .. } => {
@@ -1121,6 +1093,9 @@ fn find_vtable_types_for_unsizing<'tcx>(
             ptr_vtable(source_ty.boxed_ty(), target_ty.boxed_ty())
         }
 
+        // T as dyn* Trait
+        (_, &ty::Dynamic(_, _, ty::DynStar)) => ptr_vtable(source_ty, target_ty),
+
         (&ty::Adt(source_adt_def, source_substs), &ty::Adt(target_adt_def, target_substs)) => {
             assert_eq!(source_adt_def, target_adt_def);
 
@@ -1148,23 +1123,18 @@ fn find_vtable_types_for_unsizing<'tcx>(
     }
 }
 
-#[instrument(skip(tcx), level = "debug")]
+#[instrument(skip(tcx), level = "debug", ret)]
 fn create_fn_mono_item<'tcx>(
     tcx: TyCtxt<'tcx>,
     instance: Instance<'tcx>,
     source: Span,
 ) -> Spanned<MonoItem<'tcx>> {
-    debug!("create_fn_mono_item(instance={})", instance);
-
     let def_id = instance.def_id();
     if tcx.sess.opts.unstable_opts.profile_closures && def_id.is_local() && tcx.is_closure(def_id) {
         crate::util::dump_closure_profile(tcx, instance);
     }
 
-    let respanned = respan(source, MonoItem::Fn(instance.polymorphize(tcx)));
-    debug!(?respanned);
-
-    respanned
+    respan(source, MonoItem::Fn(instance.polymorphize(tcx)))
 }
 
 /// Creates a `MonoItem` for each method that is referenced by the vtable for
@@ -1276,7 +1246,7 @@ impl<'v> RootCollector<'_, 'v> {
                 }
             }
             DefKind::Fn => {
-                self.push_if_root(id.def_id);
+                self.push_if_root(id.def_id.def_id);
             }
             _ => {}
         }
@@ -1284,7 +1254,7 @@ impl<'v> RootCollector<'_, 'v> {
 
     fn process_impl_item(&mut self, id: hir::ImplItemId) {
         if matches!(self.tcx.def_kind(id.def_id), DefKind::AssocFn) {
-            self.push_if_root(id.def_id);
+            self.push_if_root(id.def_id.def_id);
         }
     }
 
@@ -1309,7 +1279,7 @@ impl<'v> RootCollector<'_, 'v> {
     #[instrument(skip(self), level = "debug")]
     fn push_if_root(&mut self, def_id: LocalDefId) {
         if self.is_root(def_id) {
-            debug!("RootCollector::push_if_root: found root def_id={:?}", def_id);
+            debug!("found root");
 
             let instance = Instance::mono(self.tcx, def_id.to_def_id());
             self.output.push(create_fn_mono_item(self.tcx, instance, DUMMY_SP));
@@ -1322,7 +1292,7 @@ impl<'v> RootCollector<'_, 'v> {
     /// the return type of `main`. This is not needed when
     /// the user writes their own `start` manually.
     fn push_extra_entry_roots(&mut self) {
-        let Some((main_def_id, EntryFnType::Main)) = self.entry_fn else {
+        let Some((main_def_id, EntryFnType::Main { .. })) = self.entry_fn else {
             return;
         };
 
diff --git a/compiler/rustc_monomorphize/src/errors.rs b/compiler/rustc_monomorphize/src/errors.rs
index 77b6cfa1f69f..cf6e18c013be 100644
--- a/compiler/rustc_monomorphize/src/errors.rs
+++ b/compiler/rustc_monomorphize/src/errors.rs
@@ -1,11 +1,11 @@
 use std::path::PathBuf;
 
 use rustc_errors::ErrorGuaranteed;
-use rustc_macros::{LintDiagnostic, SessionDiagnostic};
-use rustc_session::SessionDiagnostic;
+use rustc_errors::IntoDiagnostic;
+use rustc_macros::{Diagnostic, LintDiagnostic};
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize::recursion_limit)]
 pub struct RecursionLimit {
     #[primary_span]
@@ -19,7 +19,7 @@ pub struct RecursionLimit {
     pub path: PathBuf,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize::type_length_limit)]
 #[help(monomorphize::consider_type_length_limit)]
 pub struct TypeLengthLimit {
@@ -32,7 +32,7 @@ pub struct TypeLengthLimit {
     pub type_length: usize,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize::requires_lang_item)]
 pub struct RequiresLangItem {
     pub lang_item: String,
@@ -44,12 +44,13 @@ pub struct UnusedGenericParams {
     pub param_names: Vec<String>,
 }
 
-impl SessionDiagnostic<'_> for UnusedGenericParams {
+impl IntoDiagnostic<'_> for UnusedGenericParams {
     fn into_diagnostic(
         self,
-        sess: &'_ rustc_session::parse::ParseSess,
+        handler: &'_ rustc_errors::Handler,
     ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = sess.struct_err(rustc_errors::fluent::monomorphize::unused_generic_params);
+        let mut diag =
+            handler.struct_err(rustc_errors::fluent::monomorphize::unused_generic_params);
         diag.set_span(self.span);
         for (span, name) in self.param_spans.into_iter().zip(self.param_names) {
             // FIXME: I can figure out how to do a label with a fluent string with a fixed message,
@@ -71,11 +72,11 @@ pub struct LargeAssignmentsLint {
     pub limit: u64,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize::unknown_partition_strategy)]
 pub struct UnknownPartitionStrategy;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize::symbol_already_defined)]
 pub struct SymbolAlreadyDefined {
     #[primary_span]
diff --git a/compiler/rustc_monomorphize/src/lib.rs b/compiler/rustc_monomorphize/src/lib.rs
index d64de44705bb..42781bd25f05 100644
--- a/compiler/rustc_monomorphize/src/lib.rs
+++ b/compiler/rustc_monomorphize/src/lib.rs
@@ -1,6 +1,5 @@
 #![feature(array_windows)]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
@@ -35,7 +34,7 @@ fn custom_coerce_unsize_info<'tcx>(
         substs: tcx.mk_substs_trait(source_ty, &[target_ty.into()]),
     });
 
-    match tcx.codegen_fulfill_obligation((ty::ParamEnv::reveal_all(), trait_ref)) {
+    match tcx.codegen_select_candidate((ty::ParamEnv::reveal_all(), trait_ref)) {
         Ok(traits::ImplSource::UserDefined(traits::ImplSourceUserDefinedData {
             impl_def_id,
             ..
diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs
index 6e4ab2a35c33..b7e3ca571e10 100644
--- a/compiler/rustc_monomorphize/src/polymorphize.rs
+++ b/compiler/rustc_monomorphize/src/polymorphize.rs
@@ -8,8 +8,9 @@
 use rustc_hir::{def::DefKind, def_id::DefId, ConstContext};
 use rustc_index::bit_set::FiniteBitSet;
 use rustc_middle::mir::{
+    self,
     visit::{TyContext, Visitor},
-    Local, LocalDecl, Location,
+    Constant, ConstantKind, Local, LocalDecl, Location,
 };
 use rustc_middle::ty::{
     self,
@@ -33,7 +34,6 @@ pub fn provide(providers: &mut Providers) {
 ///
 /// Returns a bitset where bits representing unused parameters are set (`is_empty` indicates all
 /// parameters are used).
-#[instrument(level = "debug", skip(tcx))]
 fn unused_generic_params<'tcx>(
     tcx: TyCtxt<'tcx>,
     instance: ty::InstanceDef<'tcx>,
@@ -171,6 +171,7 @@ fn mark_used_by_default_parameters<'tcx>(
         | DefKind::AnonConst
         | DefKind::InlineConst
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Field
         | DefKind::LifetimeParam
         | DefKind::GlobalAsm
@@ -270,8 +271,15 @@ impl<'a, 'tcx> Visitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
         self.super_local_decl(local, local_decl);
     }
 
-    fn visit_const(&mut self, c: Const<'tcx>, _: Location) {
-        c.visit_with(self);
+    fn visit_constant(&mut self, ct: &Constant<'tcx>, location: Location) {
+        match ct.literal {
+            ConstantKind::Ty(c) => {
+                c.visit_with(self);
+            }
+            ConstantKind::Val(_, ty) | ConstantKind::Unevaluated(_, ty) => {
+                Visitor::visit_ty(self, ty, TyContext::Location(location))
+            }
+        }
     }
 
     fn visit_ty(&mut self, ty: Ty<'tcx>, _: TyContext) {
@@ -292,7 +300,24 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.unused_parameters.clear(param.index);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted: Some(p)})
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs })
+                if matches!(self.tcx.def_kind(def.did), DefKind::AnonConst) =>
+            {
+                self.visit_child_body(def.did, substs);
+                ControlFlow::CONTINUE
+            }
+            _ => c.super_visit_with(self),
+        }
+    }
+
+    fn visit_mir_const(&mut self, constant: ConstantKind<'tcx>) -> ControlFlow<Self::BreakTy> {
+        if !constant.has_param_types_or_consts() {
+            return ControlFlow::CONTINUE;
+        }
+
+        match constant {
+            ConstantKind::Ty(ct) => ct.visit_with(self),
+            ConstantKind::Unevaluated(mir::UnevaluatedConst { def, substs: _, promoted: Some(p) }, _)
                 // Avoid considering `T` unused when constants are of the form:
                 //   `<Self as Foo<T>>::foo::promoted[p]`
                 if self.def_id == def.did && !self.tcx.generics_of(def.did).has_self =>
@@ -303,13 +328,9 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.visit_body(&promoted[p]);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(uv)
-                if matches!(self.tcx.def_kind(uv.def.did), DefKind::AnonConst | DefKind::InlineConst) =>
-            {
-                self.visit_child_body(uv.def.did, uv.substs);
-                ControlFlow::CONTINUE
+            ConstantKind::Val(..) | ConstantKind::Unevaluated(..) => {
+                constant.super_visit_with(self)
             }
-            _ => c.super_visit_with(self),
         }
     }
 
diff --git a/compiler/rustc_monomorphize/src/util.rs b/compiler/rustc_monomorphize/src/util.rs
index 847e64dc2a2f..6a4d2df1ead1 100644
--- a/compiler/rustc_monomorphize/src/util.rs
+++ b/compiler/rustc_monomorphize/src/util.rs
@@ -13,7 +13,7 @@ pub(crate) fn dump_closure_profile<'tcx>(tcx: TyCtxt<'tcx>, closure_instance: In
         .append(true)
         .open(&format!("closure_profile_{}.csv", std::process::id()))
     else {
-        eprintln!("Cound't open file for writing closure profile");
+        eprintln!("Couldn't open file for writing closure profile");
         return;
     };
 
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 848e142e59ce..63819a2f98df 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -14,8 +14,6 @@ use rustc_session::parse::ParseSess;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{edition::Edition, BytePos, Pos, Span};
 
-use tracing::debug;
-
 mod tokentrees;
 mod unescape_error_reporting;
 mod unicode_chars;
diff --git a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
index 273827864f1a..77c4fadab45e 100644
--- a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
+++ b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
@@ -20,13 +20,9 @@ pub(crate) fn emit_unescape_error(
     range: Range<usize>,
     error: EscapeError,
 ) {
-    tracing::debug!(
+    debug!(
         "emit_unescape_error: {:?}, {:?}, {:?}, {:?}, {:?}",
-        lit,
-        span_with_quotes,
-        mode,
-        range,
-        error
+        lit, span_with_quotes, mode, range, error
     );
     let last_char = || {
         let c = lit[range.clone()].chars().rev().next().unwrap();
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index 3c88e1ef377e..06245380927c 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -4,7 +4,6 @@
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index 72ab96b5ca67..5fd69b15ecc0 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -7,8 +7,6 @@ use rustc_errors::{error_code, Diagnostic, PResult};
 use rustc_span::{sym, BytePos, Span};
 use std::convert::TryInto;
 
-use tracing::debug;
-
 // Public for rustfmt usage
 #[derive(Debug)]
 pub enum InnerAttrPolicy<'a> {
@@ -89,6 +87,7 @@ impl<'a> Parser<'a> {
                 // Always make an outer attribute - this allows us to recover from a misplaced
                 // inner attribute.
                 Some(attr::mk_doc_comment(
+                    &self.sess.attr_id_generator,
                     comment_kind,
                     ast::AttrStyle::Outer,
                     data,
@@ -140,7 +139,13 @@ impl<'a> Parser<'a> {
                     this.error_on_forbidden_inner_attr(attr_sp, inner_parse_policy);
                 }
 
-                Ok(attr::mk_attr_from_item(item, None, style, attr_sp))
+                Ok(attr::mk_attr_from_item(
+                    &self.sess.attr_id_generator,
+                    item,
+                    None,
+                    style,
+                    attr_sp,
+                ))
             } else {
                 let token_str = pprust::token_to_string(&this.token);
                 let msg = &format!("expected `#`, found `{token_str}`");
@@ -293,7 +298,13 @@ impl<'a> Parser<'a> {
             } else if let token::DocComment(comment_kind, attr_style, data) = self.token.kind {
                 if attr_style == ast::AttrStyle::Inner {
                     self.bump();
-                    Some(attr::mk_doc_comment(comment_kind, attr_style, data, self.prev_token.span))
+                    Some(attr::mk_doc_comment(
+                        &self.sess.attr_id_generator,
+                        comment_kind,
+                        attr_style,
+                        data,
+                        self.prev_token.span,
+                    ))
                 } else {
                     None
                 }
@@ -303,9 +314,9 @@ impl<'a> Parser<'a> {
             if let Some(attr) = attr {
                 let end_pos: u32 = self.token_cursor.num_next_calls.try_into().unwrap();
                 // If we are currently capturing tokens, mark the location of this inner attribute.
-                // If capturing ends up creating a `LazyTokenStream`, we will include
+                // If capturing ends up creating a `LazyAttrTokenStream`, we will include
                 // this replace range with it, removing the inner attribute from the final
-                // `AttrAnnotatedTokenStream`. Inner attributes are stored in the parsed AST note.
+                // `AttrTokenStream`. Inner attributes are stored in the parsed AST note.
                 // During macro expansion, they are selectively inserted back into the
                 // token stream (the first inner attribute is removed each time we invoke the
                 // corresponding macro).
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index b564f4ad92cf..86c386b94c83 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -1,7 +1,7 @@
 use super::{Capturing, FlatToken, ForceCollect, Parser, ReplaceRange, TokenCursor, TrailingToken};
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
-use rustc_ast::tokenstream::{AttrAnnotatedTokenStream, AttributesData, CreateTokenStream};
-use rustc_ast::tokenstream::{AttrAnnotatedTokenTree, DelimSpan, LazyTokenStream, Spacing};
+use rustc_ast::tokenstream::{AttrTokenStream, AttributesData, ToAttrTokenStream};
+use rustc_ast::tokenstream::{AttrTokenTree, DelimSpan, LazyAttrTokenStream, Spacing};
 use rustc_ast::{self as ast};
 use rustc_ast::{AttrVec, Attribute, HasAttrs, HasTokens};
 use rustc_errors::PResult;
@@ -52,7 +52,7 @@ impl AttrWrapper {
     // Prepend `self.attrs` to `attrs`.
     // FIXME: require passing an NT to prevent misuse of this method
     pub(crate) fn prepend_to_nt_inner(self, attrs: &mut AttrVec) {
-        let mut self_attrs = self.attrs.clone();
+        let mut self_attrs = self.attrs;
         std::mem::swap(attrs, &mut self_attrs);
         attrs.extend(self_attrs);
     }
@@ -88,7 +88,7 @@ fn has_cfg_or_cfg_attr(attrs: &[Attribute]) -> bool {
 // This also makes `Parser` very cheap to clone, since
 // there is no intermediate collection buffer to clone.
 #[derive(Clone)]
-struct LazyTokenStreamImpl {
+struct LazyAttrTokenStreamImpl {
     start_token: (Token, Spacing),
     cursor_snapshot: TokenCursor,
     num_calls: usize,
@@ -97,10 +97,10 @@ struct LazyTokenStreamImpl {
 }
 
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(LazyTokenStreamImpl, 144);
+rustc_data_structures::static_assert_size!(LazyAttrTokenStreamImpl, 144);
 
-impl CreateTokenStream for LazyTokenStreamImpl {
-    fn create_token_stream(&self) -> AttrAnnotatedTokenStream {
+impl ToAttrTokenStream for LazyAttrTokenStreamImpl {
+    fn to_attr_token_stream(&self) -> AttrTokenStream {
         // The token produced by the final call to `{,inlined_}next` was not
         // actually consumed by the callback. The combination of chaining the
         // initial token and using `take` produces the desired result - we
@@ -179,7 +179,7 @@ impl CreateTokenStream for LazyTokenStreamImpl {
 impl<'a> Parser<'a> {
     /// Records all tokens consumed by the provided callback,
     /// including the current token. These tokens are collected
-    /// into a `LazyTokenStream`, and returned along with the result
+    /// into a `LazyAttrTokenStream`, and returned along with the result
     /// of the callback.
     ///
     /// Note: If your callback consumes an opening delimiter
@@ -297,8 +297,8 @@ impl<'a> Parser<'a> {
 
         // If we 'broke' the last token (e.g. breaking a '>>' token to two '>' tokens),
         // then extend the range of captured tokens to include it, since the parser
-        // was not actually bumped past it. When the `LazyTokenStream` gets converted
-        // into an `AttrAnnotatedTokenStream`, we will create the proper token.
+        // was not actually bumped past it. When the `LazyAttrTokenStream` gets converted
+        // into an `AttrTokenStream`, we will create the proper token.
         if self.token_cursor.break_last_token {
             assert_eq!(
                 trailing,
@@ -316,8 +316,8 @@ impl<'a> Parser<'a> {
             Box::new([])
         } else {
             // Grab any replace ranges that occur *inside* the current AST node.
-            // We will perform the actual replacement when we convert the `LazyTokenStream`
-            // to an `AttrAnnotatedTokenStream`
+            // We will perform the actual replacement when we convert the `LazyAttrTokenStream`
+            // to an `AttrTokenStream`.
             let start_calls: u32 = cursor_snapshot_next_calls.try_into().unwrap();
             self.capture_state.replace_ranges[replace_ranges_start..replace_ranges_end]
                 .iter()
@@ -329,7 +329,7 @@ impl<'a> Parser<'a> {
                 .collect()
         };
 
-        let tokens = LazyTokenStream::new(LazyTokenStreamImpl {
+        let tokens = LazyAttrTokenStream::new(LazyAttrTokenStreamImpl {
             start_token,
             num_calls,
             cursor_snapshot,
@@ -355,7 +355,7 @@ impl<'a> Parser<'a> {
             && matches!(self.capture_state.capturing, Capturing::Yes)
             && has_cfg_or_cfg_attr(final_attrs)
         {
-            let attr_data = AttributesData { attrs: final_attrs.to_vec().into(), tokens };
+            let attr_data = AttributesData { attrs: final_attrs.iter().cloned().collect(), tokens };
 
             // Replace the entire AST node that we just parsed, including attributes,
             // with a `FlatToken::AttrTarget`. If this AST node is inside an item
@@ -392,12 +392,12 @@ impl<'a> Parser<'a> {
 fn make_token_stream(
     mut iter: impl Iterator<Item = (FlatToken, Spacing)>,
     break_last_token: bool,
-) -> AttrAnnotatedTokenStream {
+) -> AttrTokenStream {
     #[derive(Debug)]
     struct FrameData {
         // This is `None` for the first frame, `Some` for all others.
         open_delim_sp: Option<(Delimiter, Span)>,
-        inner: Vec<(AttrAnnotatedTokenTree, Spacing)>,
+        inner: Vec<AttrTokenTree>,
     }
     let mut stack = vec![FrameData { open_delim_sp: None, inner: vec![] }];
     let mut token_and_spacing = iter.next();
@@ -418,48 +418,46 @@ fn make_token_stream(
                     open_delim, span
                 );
                 let dspan = DelimSpan::from_pair(open_sp, span);
-                let stream = AttrAnnotatedTokenStream::new(frame_data.inner);
-                let delimited = AttrAnnotatedTokenTree::Delimited(dspan, delim, stream);
+                let stream = AttrTokenStream::new(frame_data.inner);
+                let delimited = AttrTokenTree::Delimited(dspan, delim, stream);
                 stack
                     .last_mut()
                     .unwrap_or_else(|| {
                         panic!("Bottom token frame is missing for token: {:?}", token)
                     })
                     .inner
-                    .push((delimited, Spacing::Alone));
+                    .push(delimited);
             }
             FlatToken::Token(token) => stack
                 .last_mut()
                 .expect("Bottom token frame is missing!")
                 .inner
-                .push((AttrAnnotatedTokenTree::Token(token), spacing)),
+                .push(AttrTokenTree::Token(token, spacing)),
             FlatToken::AttrTarget(data) => stack
                 .last_mut()
                 .expect("Bottom token frame is missing!")
                 .inner
-                .push((AttrAnnotatedTokenTree::Attributes(data), spacing)),
+                .push(AttrTokenTree::Attributes(data)),
             FlatToken::Empty => {}
         }
         token_and_spacing = iter.next();
     }
     let mut final_buf = stack.pop().expect("Missing final buf!");
     if break_last_token {
-        let (last_token, spacing) = final_buf.inner.pop().unwrap();
-        if let AttrAnnotatedTokenTree::Token(last_token) = last_token {
+        let last_token = final_buf.inner.pop().unwrap();
+        if let AttrTokenTree::Token(last_token, spacing) = last_token {
             let unglued_first = last_token.kind.break_two_token_op().unwrap().0;
 
             // An 'unglued' token is always two ASCII characters
             let mut first_span = last_token.span.shrink_to_lo();
             first_span = first_span.with_hi(first_span.lo() + rustc_span::BytePos(1));
 
-            final_buf.inner.push((
-                AttrAnnotatedTokenTree::Token(Token::new(unglued_first, first_span)),
-                spacing,
-            ));
+            final_buf
+                .inner
+                .push(AttrTokenTree::Token(Token::new(unglued_first, first_span), spacing));
         } else {
             panic!("Unexpected last token {:?}", last_token)
         }
     }
-    assert!(stack.is_empty(), "Stack should be empty: final_buf={:?} stack={:?}", final_buf, stack);
-    AttrAnnotatedTokenStream::new(final_buf.inner)
+    AttrTokenStream::new(final_buf.inner)
 }
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index f0ea1dfe297f..ccdffb8ce07b 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -10,9 +10,9 @@ use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, Lit, LitKind, TokenKind};
 use rustc_ast::util::parser::AssocOp;
 use rustc_ast::{
-    AngleBracketedArg, AngleBracketedArgs, AnonConst, AttrVec, BinOpKind, BindingMode, Block,
-    BlockCheckMode, Expr, ExprKind, GenericArg, Generics, Item, ItemKind, Mutability, Param, Pat,
-    PatKind, Path, PathSegment, QSelf, Ty, TyKind,
+    AngleBracketedArg, AngleBracketedArgs, AnonConst, AttrVec, BinOpKind, BindingAnnotation, Block,
+    BlockCheckMode, Expr, ExprKind, GenericArg, Generics, Item, ItemKind, Param, Pat, PatKind,
+    Path, PathSegment, QSelf, Ty, TyKind,
 };
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
@@ -20,7 +20,7 @@ use rustc_errors::{
     fluent, Applicability, DiagnosticBuilder, DiagnosticMessage, Handler, MultiSpan, PResult,
 };
 use rustc_errors::{pluralize, struct_span_err, Diagnostic, ErrorGuaranteed};
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
+use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{Span, SpanSnippetError, DUMMY_SP};
@@ -29,7 +29,6 @@ use std::ops::{Deref, DerefMut};
 use std::mem::take;
 
 use crate::parser;
-use tracing::{debug, trace};
 
 const TURBOFISH_SUGGESTION_STR: &str =
     "use `::<...>` instead of `<...>` to specify lifetime, type, or const arguments";
@@ -38,7 +37,7 @@ const TURBOFISH_SUGGESTION_STR: &str =
 pub(super) fn dummy_arg(ident: Ident) -> Param {
     let pat = P(Pat {
         id: ast::DUMMY_NODE_ID,
-        kind: PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None),
+        kind: PatKind::Ident(BindingAnnotation::NONE, ident, None),
         span: ident.span,
         tokens: None,
     });
@@ -243,7 +242,7 @@ impl MultiSugg {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::maybe_report_ambiguous_plus)]
 struct AmbiguousPlus {
     pub sum_ty: String,
@@ -252,7 +251,7 @@ struct AmbiguousPlus {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::maybe_recover_from_bad_type_plus, code = "E0178")]
 struct BadTypePlus {
     pub ty: String,
@@ -262,7 +261,7 @@ struct BadTypePlus {
     pub sub: BadTypePlusSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum BadTypePlusSub {
     #[suggestion(
         parser::add_paren,
@@ -286,35 +285,35 @@ pub enum BadTypePlusSub {
     },
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::maybe_recover_from_bad_qpath_stage_2)]
 struct BadQPathStage2 {
     #[primary_span]
-    #[suggestion(applicability = "maybe-incorrect")]
+    #[suggestion(code = "", applicability = "maybe-incorrect")]
     span: Span,
     ty: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::incorrect_semicolon)]
 struct IncorrectSemicolon<'a> {
     #[primary_span]
-    #[suggestion_short(applicability = "machine-applicable")]
+    #[suggestion_short(code = "", applicability = "machine-applicable")]
     span: Span,
     #[help]
     opt_help: Option<()>,
     name: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::incorrect_use_of_await)]
 struct IncorrectUseOfAwait {
     #[primary_span]
-    #[suggestion(parser::parentheses_suggestion, applicability = "machine-applicable")]
+    #[suggestion(parser::parentheses_suggestion, code = "", applicability = "machine-applicable")]
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::incorrect_use_of_await)]
 struct IncorrectAwait {
     #[primary_span]
@@ -325,16 +324,16 @@ struct IncorrectAwait {
     question_mark: &'static str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::in_in_typo)]
 struct InInTypo {
     #[primary_span]
     span: Span,
-    #[suggestion(applicability = "machine-applicable")]
+    #[suggestion(code = "", applicability = "machine-applicable")]
     sugg_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_variable_declaration)]
 pub struct InvalidVariableDeclaration {
     #[primary_span]
@@ -343,7 +342,7 @@ pub struct InvalidVariableDeclaration {
     pub sub: InvalidVariableDeclarationSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum InvalidVariableDeclarationSub {
     #[suggestion(
         parser::switch_mut_let_order,
@@ -363,7 +362,7 @@ pub enum InvalidVariableDeclarationSub {
     UseLetNotVar(#[primary_span] Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_comparison_operator)]
 pub(crate) struct InvalidComparisonOperator {
     #[primary_span]
@@ -373,7 +372,7 @@ pub(crate) struct InvalidComparisonOperator {
     pub sub: InvalidComparisonOperatorSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum InvalidComparisonOperatorSub {
     #[suggestion_short(
         parser::use_instead,
@@ -390,7 +389,7 @@ pub(crate) enum InvalidComparisonOperatorSub {
     Spaceship(#[primary_span] Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_logical_operator)]
 #[note]
 pub(crate) struct InvalidLogicalOperator {
@@ -401,7 +400,7 @@ pub(crate) struct InvalidLogicalOperator {
     pub sub: InvalidLogicalOperatorSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum InvalidLogicalOperatorSub {
     #[suggestion_short(
         parser::use_amp_amp_for_conjunction,
@@ -417,7 +416,7 @@ pub(crate) enum InvalidLogicalOperatorSub {
     Disjunction(#[primary_span] Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::tilde_is_not_unary_operator)]
 pub(crate) struct TildeAsUnaryOperator(
     #[primary_span]
@@ -425,17 +424,41 @@ pub(crate) struct TildeAsUnaryOperator(
     pub Span,
 );
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::unexpected_token_after_not)]
 pub(crate) struct NotAsNegationOperator {
     #[primary_span]
     pub negated: Span,
     pub negated_desc: String,
-    #[suggestion_short(applicability = "machine-applicable", code = "!")]
-    pub not: Span,
+    #[subdiagnostic]
+    pub sub: NotAsNegationOperatorSub,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Subdiagnostic)]
+pub enum NotAsNegationOperatorSub {
+    #[suggestion_short(
+        parser::unexpected_token_after_not_default,
+        applicability = "machine-applicable",
+        code = "!"
+    )]
+    SuggestNotDefault(#[primary_span] Span),
+
+    #[suggestion_short(
+        parser::unexpected_token_after_not_bitwise,
+        applicability = "machine-applicable",
+        code = "!"
+    )]
+    SuggestNotBitwise(#[primary_span] Span),
+
+    #[suggestion_short(
+        parser::unexpected_token_after_not_logical,
+        applicability = "machine-applicable",
+        code = "!"
+    )]
+    SuggestNotLogical(#[primary_span] Span),
+}
+
+#[derive(Diagnostic)]
 #[diag(parser::malformed_loop_label)]
 pub(crate) struct MalformedLoopLabel {
     #[primary_span]
@@ -444,7 +467,7 @@ pub(crate) struct MalformedLoopLabel {
     pub correct_label: Ident,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::lifetime_in_borrow_expression)]
 pub(crate) struct LifetimeInBorrowExpression {
     #[primary_span]
@@ -454,15 +477,15 @@ pub(crate) struct LifetimeInBorrowExpression {
     pub lifetime_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::field_expression_with_generic)]
 pub(crate) struct FieldExpressionWithGeneric(#[primary_span] pub Span);
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::macro_invocation_with_qualified_path)]
 pub(crate) struct MacroInvocationWithQualifiedPath(#[primary_span] pub Span);
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::unexpected_token_after_label)]
 pub(crate) struct UnexpectedTokenAfterLabel(
     #[primary_span]
@@ -470,7 +493,7 @@ pub(crate) struct UnexpectedTokenAfterLabel(
     pub Span,
 );
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::require_colon_after_labeled_expression)]
 #[note]
 pub(crate) struct RequireColonAfterLabeledExpression {
@@ -482,7 +505,7 @@ pub(crate) struct RequireColonAfterLabeledExpression {
     pub label_end: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::do_catch_syntax_removed)]
 #[note]
 pub(crate) struct DoCatchSyntaxRemoved {
@@ -491,7 +514,7 @@ pub(crate) struct DoCatchSyntaxRemoved {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::float_literal_requires_integer_part)]
 pub(crate) struct FloatLiteralRequiresIntegerPart {
     #[primary_span]
@@ -500,7 +523,7 @@ pub(crate) struct FloatLiteralRequiresIntegerPart {
     pub correct: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_int_literal_width)]
 #[help]
 pub(crate) struct InvalidIntLiteralWidth {
@@ -509,7 +532,7 @@ pub(crate) struct InvalidIntLiteralWidth {
     pub width: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_num_literal_base_prefix)]
 #[note]
 pub(crate) struct InvalidNumLiteralBasePrefix {
@@ -519,7 +542,7 @@ pub(crate) struct InvalidNumLiteralBasePrefix {
     pub fixed: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_num_literal_suffix)]
 #[help]
 pub(crate) struct InvalidNumLiteralSuffix {
@@ -529,7 +552,7 @@ pub(crate) struct InvalidNumLiteralSuffix {
     pub suffix: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_float_literal_width)]
 #[help]
 pub(crate) struct InvalidFloatLiteralWidth {
@@ -538,7 +561,7 @@ pub(crate) struct InvalidFloatLiteralWidth {
     pub width: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_float_literal_suffix)]
 #[help]
 pub(crate) struct InvalidFloatLiteralSuffix {
@@ -548,14 +571,14 @@ pub(crate) struct InvalidFloatLiteralSuffix {
     pub suffix: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::int_literal_too_large)]
 pub(crate) struct IntLiteralTooLarge {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::missing_semicolon_before_array)]
 pub(crate) struct MissingSemicolonBeforeArray {
     #[primary_span]
@@ -564,7 +587,7 @@ pub(crate) struct MissingSemicolonBeforeArray {
     pub semicolon: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::invalid_block_macro_segment)]
 pub(crate) struct InvalidBlockMacroSegment {
     #[primary_span]
@@ -573,7 +596,7 @@ pub(crate) struct InvalidBlockMacroSegment {
     pub context: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::if_expression_missing_then_block)]
 pub(crate) struct IfExpressionMissingThenBlock {
     #[primary_span]
@@ -582,7 +605,7 @@ pub(crate) struct IfExpressionMissingThenBlock {
     pub sub: IfExpressionMissingThenBlockSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum IfExpressionMissingThenBlockSub {
     #[help(parser::condition_possibly_unfinished)]
     UnfinishedCondition(#[primary_span] Span),
@@ -590,7 +613,7 @@ pub(crate) enum IfExpressionMissingThenBlockSub {
     AddThenBlock(#[primary_span] Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::if_expression_missing_condition)]
 pub(crate) struct IfExpressionMissingCondition {
     #[primary_span]
@@ -600,14 +623,14 @@ pub(crate) struct IfExpressionMissingCondition {
     pub block_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::expected_expression_found_let)]
 pub(crate) struct ExpectedExpressionFoundLet {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::expected_else_block)]
 pub(crate) struct ExpectedElseBlock {
     #[primary_span]
@@ -619,7 +642,7 @@ pub(crate) struct ExpectedElseBlock {
     pub condition_start: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::outer_attribute_not_allowed_on_if_else)]
 pub(crate) struct OuterAttributeNotAllowedOnIfElse {
     #[primary_span]
@@ -636,7 +659,7 @@ pub(crate) struct OuterAttributeNotAllowedOnIfElse {
     pub attributes: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::missing_in_in_for_loop)]
 pub(crate) struct MissingInInForLoop {
     #[primary_span]
@@ -645,7 +668,7 @@ pub(crate) struct MissingInInForLoop {
     pub sub: MissingInInForLoopSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub(crate) enum MissingInInForLoopSub {
     // Has been misleading, at least in the past (closed Issue #48492), thus maybe-incorrect
     #[suggestion_short(parser::use_in_not_of, applicability = "maybe-incorrect", code = "in")]
@@ -654,7 +677,7 @@ pub(crate) enum MissingInInForLoopSub {
     AddIn(#[primary_span] Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::missing_comma_after_match_arm)]
 pub(crate) struct MissingCommaAfterMatchArm {
     #[primary_span]
@@ -662,7 +685,7 @@ pub(crate) struct MissingCommaAfterMatchArm {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::catch_after_try)]
 #[help]
 pub(crate) struct CatchAfterTry {
@@ -670,7 +693,7 @@ pub(crate) struct CatchAfterTry {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::comma_after_base_struct)]
 #[note]
 pub(crate) struct CommaAfterBaseStruct {
@@ -680,7 +703,7 @@ pub(crate) struct CommaAfterBaseStruct {
     pub comma: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::eq_field_init)]
 pub(crate) struct EqFieldInit {
     #[primary_span]
@@ -689,7 +712,7 @@ pub(crate) struct EqFieldInit {
     pub eq: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::dotdotdot)]
 pub(crate) struct DotDotDot {
     #[primary_span]
@@ -698,7 +721,7 @@ pub(crate) struct DotDotDot {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::left_arrow_operator)]
 pub(crate) struct LeftArrowOperator {
     #[primary_span]
@@ -706,6 +729,30 @@ pub(crate) struct LeftArrowOperator {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(parser::remove_let)]
+pub(crate) struct RemoveLet {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = "")]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(parser::use_eq_instead)]
+pub(crate) struct UseEqInstead {
+    #[primary_span]
+    #[suggestion_short(applicability = "machine-applicable", code = "=")]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(parser::use_empty_block_not_semi)]
+pub(crate) struct UseEmptyBlockNotSemi {
+    #[primary_span]
+    #[suggestion_hidden(applicability = "machine-applicable", code = "{{}}")]
+    pub span: Span,
+}
+
 // SnapshotParser is used to create a snapshot of the parser
 // without causing duplicate errors being emitted when the `Parser`
 // is dropped.
@@ -950,6 +997,14 @@ impl<'a> Parser<'a> {
             }
         }
 
+        if self.token.kind == TokenKind::EqEq
+            && self.prev_token.is_ident()
+            && expected.iter().any(|tok| matches!(tok, TokenType::Token(TokenKind::Eq)))
+        {
+            // Likely typo: `=` → `==` in let expr or enum item
+            return Err(self.sess.create_err(UseEqInstead { span: self.token.span }));
+        }
+
         let expect = tokens_to_string(&expected);
         let actual = super::token_descr(&self.token);
         let (msg_exp, (label_sp, label_exp)) = if expected.len() > 1 {
@@ -2962,7 +3017,7 @@ impl<'a> Parser<'a> {
                                 }
                                 _ => {}
                             },
-                            PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
+                            PatKind::Ident(BindingAnnotation::NONE, ident, None) => {
                                 match &first_pat.kind {
                                     PatKind::Ident(_, old_ident, _) => {
                                         let path = PatKind::Path(
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index c85416095144..ae77961b7bc2 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -6,8 +6,9 @@ use super::diagnostics::{
     InvalidComparisonOperatorSub, InvalidLogicalOperator, InvalidLogicalOperatorSub,
     LeftArrowOperator, LifetimeInBorrowExpression, MacroInvocationWithQualifiedPath,
     MalformedLoopLabel, MissingInInForLoop, MissingInInForLoopSub, MissingSemicolonBeforeArray,
-    NotAsNegationOperator, OuterAttributeNotAllowedOnIfElse, RequireColonAfterLabeledExpression,
-    SnapshotParser, TildeAsUnaryOperator, UnexpectedTokenAfterLabel,
+    NotAsNegationOperator, NotAsNegationOperatorSub, OuterAttributeNotAllowedOnIfElse,
+    RequireColonAfterLabeledExpression, SnapshotParser, TildeAsUnaryOperator,
+    UnexpectedTokenAfterLabel,
 };
 use super::pat::{CommaRecoveryMode, RecoverColon, RecoverComma, PARAM_EXPECTED};
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
@@ -35,10 +36,10 @@ use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty
 use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
 use rustc_ast::{ClosureBinder, StmtKind};
 use rustc_ast_pretty::pprust;
+use rustc_errors::IntoDiagnostic;
 use rustc_errors::{Applicability, Diagnostic, PResult};
 use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
 use rustc_session::lint::BuiltinLintDiagnostics;
-use rustc_session::SessionDiagnostic;
 use rustc_span::source_map::{self, Span, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Pos};
@@ -660,12 +661,23 @@ impl<'a> Parser<'a> {
     fn recover_not_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
         // Emit the error...
         let negated_token = self.look_ahead(1, |t| t.clone());
+
+        let sub_diag = if negated_token.is_numeric_lit() {
+            NotAsNegationOperatorSub::SuggestNotBitwise
+        } else if negated_token.is_bool_lit() {
+            NotAsNegationOperatorSub::SuggestNotLogical
+        } else {
+            NotAsNegationOperatorSub::SuggestNotDefault
+        };
+
         self.sess.emit_err(NotAsNegationOperator {
             negated: negated_token.span,
             negated_desc: super::token_descr(&negated_token),
             // Span the `not` plus trailing whitespace to avoid
             // trailing whitespace after the `!` in our suggestion
-            not: self.sess.source_map().span_until_non_whitespace(lo.to(negated_token.span)),
+            sub: sub_diag(
+                self.sess.source_map().span_until_non_whitespace(lo.to(negated_token.span)),
+            ),
         });
 
         // ...and recover!
@@ -944,13 +956,18 @@ impl<'a> Parser<'a> {
         // Stitch the list of outer attributes onto the return value.
         // A little bit ugly, but the best way given the current code
         // structure
-        self.parse_dot_or_call_expr_with_(e0, lo).map(|expr| {
-            expr.map(|mut expr| {
-                attrs.extend(expr.attrs);
-                expr.attrs = attrs;
-                expr
+        let res = self.parse_dot_or_call_expr_with_(e0, lo);
+        if attrs.is_empty() {
+            res
+        } else {
+            res.map(|expr| {
+                expr.map(|mut expr| {
+                    attrs.extend(expr.attrs);
+                    expr.attrs = attrs;
+                    expr
+                })
             })
-        })
+        }
     }
 
     fn parse_dot_or_call_expr_with_(&mut self, mut e: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
@@ -1578,7 +1595,7 @@ impl<'a> Parser<'a> {
                     Applicability::MachineApplicable,
                 );
 
-                // Replace `'label: non_block_expr` with `'label: {non_block_expr}` in order to supress future errors about `break 'label`.
+                // Replace `'label: non_block_expr` with `'label: {non_block_expr}` in order to suppress future errors about `break 'label`.
                 let stmt = self.mk_stmt(span, StmtKind::Expr(expr));
                 let blk = self.mk_block(vec![stmt], BlockCheckMode::Default, span);
                 self.mk_expr(span, ExprKind::Block(blk, label))
@@ -1972,6 +1989,9 @@ impl<'a> Parser<'a> {
         open_delim_span: Span,
     ) -> PResult<'a, ()> {
         if self.token.kind == token::Comma {
+            if !self.sess.source_map().is_multiline(prev_span.until(self.token.span)) {
+                return Ok(());
+            }
             let mut snapshot = self.create_snapshot_for_diagnostic();
             snapshot.bump();
             match snapshot.parse_seq_to_before_end(
@@ -1992,7 +2012,7 @@ impl<'a> Parser<'a> {
                     return Err(MissingSemicolonBeforeArray {
                         open_delim: open_delim_span,
                         semicolon: prev_span.shrink_to_hi(),
-                    }.into_diagnostic(self.sess));
+                    }.into_diagnostic(&self.sess.span_diagnostic));
                 }
                 Ok(_) => (),
                 Err(err) => err.cancel(),
@@ -2578,7 +2598,7 @@ impl<'a> Parser<'a> {
     }
 
     pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
-        // Used to check the `let_chains` and `if_let_guard` features mostly by scaning
+        // Used to check the `let_chains` and `if_let_guard` features mostly by scanning
         // `&&` tokens.
         fn check_let_expr(expr: &Expr) -> (bool, bool) {
             match expr.kind {
@@ -2740,7 +2760,8 @@ impl<'a> Parser<'a> {
     fn parse_try_block(&mut self, span_lo: Span) -> PResult<'a, P<Expr>> {
         let (attrs, body) = self.parse_inner_attrs_and_block()?;
         if self.eat_keyword(kw::Catch) {
-            Err(CatchAfterTry { span: self.prev_token.span }.into_diagnostic(self.sess))
+            Err(CatchAfterTry { span: self.prev_token.span }
+                .into_diagnostic(&self.sess.span_diagnostic))
         } else {
             let span = span_lo.to(body.span);
             self.sess.gated_spans.gate(sym::try_blocks, span);
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index b743162a7e4d..34f25bd0716a 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -1,4 +1,4 @@
-use super::diagnostics::{dummy_arg, ConsumeClosingDelim, Error};
+use super::diagnostics::{dummy_arg, ConsumeClosingDelim, Error, UseEmptyBlockNotSemi};
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{AttrWrapper, FollowedByType, ForceCollect, Parser, PathStyle, TrailingToken};
 
@@ -8,7 +8,7 @@ use rustc_ast::token::{self, Delimiter, TokenKind};
 use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree};
 use rustc_ast::{self as ast, AttrVec, Attribute, DUMMY_NODE_ID};
 use rustc_ast::{Async, Const, Defaultness, IsAuto, Mutability, Unsafe, UseTree, UseTreeKind};
-use rustc_ast::{BindingMode, Block, FnDecl, FnSig, Param, SelfKind};
+use rustc_ast::{BindingAnnotation, Block, FnDecl, FnSig, Param, SelfKind};
 use rustc_ast::{EnumDef, FieldDef, Generics, TraitRef, Ty, TyKind, Variant, VariantData};
 use rustc_ast::{FnHeader, ForeignItem, Path, PathSegment, Visibility, VisibilityKind};
 use rustc_ast::{MacArgs, MacCall, MacDelimiter};
@@ -22,7 +22,6 @@ use rustc_span::DUMMY_SP;
 
 use std::convert::TryFrom;
 use std::mem;
-use tracing::debug;
 
 impl<'a> Parser<'a> {
     /// Parses a source module as a crate. This is the main entry point for the parser.
@@ -665,6 +664,14 @@ impl<'a> Parser<'a> {
         mut parse_item: impl FnMut(&mut Parser<'a>) -> PResult<'a, Option<Option<T>>>,
     ) -> PResult<'a, Vec<T>> {
         let open_brace_span = self.token.span;
+
+        // Recover `impl Ty;` instead of `impl Ty {}`
+        if self.token == TokenKind::Semi {
+            self.sess.emit_err(UseEmptyBlockNotSemi { span: self.token.span });
+            self.bump();
+            return Ok(vec![]);
+        }
+
         self.expect(&token::OpenDelim(Delimiter::Brace))?;
         attrs.extend(self.parse_inner_attributes()?);
 
@@ -699,11 +706,22 @@ impl<'a> Parser<'a> {
                     let semicolon_span = self.token.span;
                     // We have to bail or we'll potentially never make progress.
                     let non_item_span = self.token.span;
-                    self.consume_block(Delimiter::Brace, ConsumeClosingDelim::Yes);
+                    let is_let = self.token.is_keyword(kw::Let);
+
                     let mut err = self.struct_span_err(non_item_span, "non-item in item list");
-                    err.span_label(open_brace_span, "item list starts here")
-                        .span_label(non_item_span, "non-item starts here")
-                        .span_label(self.prev_token.span, "item list ends here");
+                    self.consume_block(Delimiter::Brace, ConsumeClosingDelim::Yes);
+                    if is_let {
+                        err.span_suggestion(
+                            non_item_span,
+                            "consider using `const` instead of `let` for associated const",
+                            "const",
+                            Applicability::MachineApplicable,
+                        );
+                    } else {
+                        err.span_label(open_brace_span, "item list starts here")
+                            .span_label(non_item_span, "non-item starts here")
+                            .span_label(self.prev_token.span, "item list ends here");
+                    }
                     if is_unnecessary_semicolon {
                         err.span_suggestion(
                             semicolon_span,
@@ -1295,12 +1313,19 @@ impl<'a> Parser<'a> {
         let mut generics = self.parse_generics()?;
         generics.where_clause = self.parse_where_clause()?;
 
-        let (variants, _) = self
-            .parse_delim_comma_seq(Delimiter::Brace, |p| p.parse_enum_variant())
-            .map_err(|e| {
-                self.recover_stmt();
-                e
-            })?;
+        // Possibly recover `enum Foo;` instead of `enum Foo {}`
+        let (variants, _) = if self.token == TokenKind::Semi {
+            self.sess.emit_err(UseEmptyBlockNotSemi { span: self.token.span });
+            self.bump();
+            (vec![], false)
+        } else {
+            self.parse_delim_comma_seq(Delimiter::Brace, |p| p.parse_enum_variant()).map_err(
+                |e| {
+                    self.recover_stmt();
+                    e
+                },
+            )?
+        };
 
         let enum_definition = EnumDef { variants: variants.into_iter().flatten().collect() };
         Ok((id, ItemKind::Enum(enum_definition, generics)))
@@ -1527,6 +1552,17 @@ impl<'a> Parser<'a> {
         if self.token == token::Comma {
             seen_comma = true;
         }
+        if self.eat(&token::Semi) {
+            let sp = self.prev_token.span;
+            let mut err = self.struct_span_err(sp, format!("{adt_ty} fields are separated by `,`"));
+            err.span_suggestion_short(
+                sp,
+                "replace `;` with `,`",
+                ",",
+                Applicability::MachineApplicable,
+            );
+            return Err(err);
+        }
         match self.token.kind {
             token::Comma => {
                 self.bump();
@@ -1694,6 +1730,7 @@ impl<'a> Parser<'a> {
     fn parse_field_ident(&mut self, adt_ty: &str, lo: Span) -> PResult<'a, Ident> {
         let (ident, is_raw) = self.ident_or_err()?;
         if !is_raw && ident.is_reserved() {
+            let snapshot = self.create_snapshot_for_diagnostic();
             let err = if self.check_fn_front_matter(false) {
                 let inherited_vis = Visibility {
                     span: rustc_span::DUMMY_SP,
@@ -1714,6 +1751,22 @@ impl<'a> Parser<'a> {
                 err.help("unlike in C++, Java, and C#, functions are declared in `impl` blocks");
                 err.help("see https://doc.rust-lang.org/book/ch05-03-method-syntax.html for more information");
                 err
+            } else if self.eat_keyword(kw::Struct) {
+                match self.parse_item_struct() {
+                    Ok((ident, _)) => {
+                        let mut err = self.struct_span_err(
+                            lo.with_hi(ident.span.hi()),
+                            &format!("structs are not allowed in {adt_ty} definitions"),
+                        );
+                        err.help("consider creating a new `struct` definition instead of nesting");
+                        err
+                    }
+                    Err(err) => {
+                        err.cancel();
+                        self.restore_snapshot(snapshot);
+                        self.expected_ident_found()
+                    }
+                }
             } else {
                 self.expected_ident_found()
             };
@@ -2323,7 +2376,7 @@ impl<'a> Parser<'a> {
                 match ty {
                     Ok(ty) => {
                         let ident = Ident::new(kw::Empty, this.prev_token.span);
-                        let bm = BindingMode::ByValue(Mutability::Not);
+                        let bm = BindingAnnotation::NONE;
                         let pat = this.mk_pat_ident(ty.span, bm, ident);
                         (pat, ty)
                     }
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index f6516d3bd454..4cb198561e0a 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -37,7 +37,6 @@ use rustc_errors::{
 use rustc_session::parse::ParseSess;
 use rustc_span::source_map::{Span, DUMMY_SP};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use tracing::debug;
 
 use std::ops::Range;
 use std::{cmp, mem, slice};
@@ -171,7 +170,7 @@ pub struct ClosureSpans {
 /// attribute, we parse a nested AST node that has `#[cfg]` or `#[cfg_attr]`
 /// In this case, we use a `ReplaceRange` to replace the entire inner AST node
 /// with `FlatToken::AttrTarget`, allowing us to perform eager cfg-expansion
-/// on an `AttrAnnotatedTokenStream`
+/// on an `AttrTokenStream`.
 ///
 /// 2. When we parse an inner attribute while collecting tokens. We
 /// remove inner attributes from the token stream entirely, and
@@ -184,7 +183,7 @@ pub type ReplaceRange = (Range<u32>, Vec<(FlatToken, Spacing)>);
 
 /// Controls how we capture tokens. Capturing can be expensive,
 /// so we try to avoid performing capturing in cases where
-/// we will never need an `AttrAnnotatedTokenStream`
+/// we will never need an `AttrTokenStream`.
 #[derive(Copy, Clone)]
 pub enum Capturing {
     /// We aren't performing any capturing - this is the default mode.
@@ -238,7 +237,7 @@ struct TokenCursor {
     // the trailing `>>` token. The `break_last_token`
     // field is used to track this token - it gets
     // appended to the captured stream when
-    // we evaluate a `LazyTokenStream`
+    // we evaluate a `LazyAttrTokenStream`.
     break_last_token: bool,
 }
 
@@ -281,7 +280,7 @@ impl TokenCursor {
                         if delim != Delimiter::Invisible {
                             return (Token::new(token::OpenDelim(delim), sp.open), Spacing::Alone);
                         }
-                        // No open delimeter to return; continue on to the next iteration.
+                        // No open delimiter to return; continue on to the next iteration.
                     }
                 };
             } else if let Some(frame) = self.stack.pop() {
@@ -1465,11 +1464,11 @@ pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, sess: &Pa
     }
 }
 
-/// A helper struct used when building an `AttrAnnotatedTokenStream` from
-/// a `LazyTokenStream`. Both delimiter and non-delimited tokens
+/// A helper struct used when building an `AttrTokenStream` from
+/// a `LazyAttrTokenStream`. Both delimiter and non-delimited tokens
 /// are stored as `FlatToken::Token`. A vector of `FlatToken`s
-/// is then 'parsed' to build up an `AttrAnnotatedTokenStream` with nested
-/// `AttrAnnotatedTokenTree::Delimited` tokens
+/// is then 'parsed' to build up an `AttrTokenStream` with nested
+/// `AttrTokenTree::Delimited` tokens.
 #[derive(Debug, Clone)]
 pub enum FlatToken {
     /// A token - this holds both delimiter (e.g. '{' and '}')
@@ -1477,11 +1476,11 @@ pub enum FlatToken {
     Token(Token),
     /// Holds the `AttributesData` for an AST node. The
     /// `AttributesData` is inserted directly into the
-    /// constructed `AttrAnnotatedTokenStream` as
-    /// an `AttrAnnotatedTokenTree::Attributes`
+    /// constructed `AttrTokenStream` as
+    /// an `AttrTokenTree::Attributes`.
     AttrTarget(AttributesData),
     /// A special 'empty' token that is ignored during the conversion
-    /// to an `AttrAnnotatedTokenStream`. This is used to simplify the
+    /// to an `AttrTokenStream`. This is used to simplify the
     /// handling of replace ranges.
     Empty,
 }
diff --git a/compiler/rustc_parse/src/parser/nonterminal.rs b/compiler/rustc_parse/src/parser/nonterminal.rs
index e215b6872bff..103dd801257a 100644
--- a/compiler/rustc_parse/src/parser/nonterminal.rs
+++ b/compiler/rustc_parse/src/parser/nonterminal.rs
@@ -66,18 +66,18 @@ impl<'a> Parser<'a> {
             },
             NonterminalKind::PatParam { .. } | NonterminalKind::PatWithOr { .. } => {
                 match token.kind {
-                token::Ident(..) |                  // box, ref, mut, and other identifiers (can stricten)
-                token::OpenDelim(Delimiter::Parenthesis) |    // tuple pattern
-                token::OpenDelim(Delimiter::Bracket) |  // slice pattern
-                token::BinOp(token::And) |          // reference
-                token::BinOp(token::Minus) |        // negative literal
-                token::AndAnd |                     // double reference
-                token::Literal(..) |                // literal
-                token::DotDot |                     // range pattern (future compat)
-                token::DotDotDot |                  // range pattern (future compat)
-                token::ModSep |                     // path
-                token::Lt |                         // path (UFCS constant)
-                token::BinOp(token::Shl) => true,   // path (double UFCS)
+                token::Ident(..) |                          // box, ref, mut, and other identifiers (can stricten)
+                token::OpenDelim(Delimiter::Parenthesis) |  // tuple pattern
+                token::OpenDelim(Delimiter::Bracket) |      // slice pattern
+                token::BinOp(token::And) |                  // reference
+                token::BinOp(token::Minus) |                // negative literal
+                token::AndAnd |                             // double reference
+                token::Literal(..) |                        // literal
+                token::DotDot |                             // range pattern (future compat)
+                token::DotDotDot |                          // range pattern (future compat)
+                token::ModSep |                             // path
+                token::Lt |                                 // path (UFCS constant)
+                token::BinOp(token::Shl) => true,           // path (double UFCS)
                 // leading vert `|` or-pattern
                 token::BinOp(token::Or) =>  matches!(kind, NonterminalKind::PatWithOr {..}),
                 token::Interpolated(ref nt) => may_be_ident(nt),
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 8b3200d45fcc..120a3c267f10 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -1,11 +1,12 @@
 use super::{ForceCollect, Parser, PathStyle, TrailingToken};
+use crate::parser::diagnostics::RemoveLet;
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 use rustc_ast::mut_visit::{noop_visit_pat, MutVisitor};
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter};
 use rustc_ast::{
-    self as ast, AttrVec, BindingMode, Expr, ExprKind, MacCall, Mutability, Pat, PatField, PatKind,
-    Path, QSelf, RangeEnd, RangeSyntax,
+    self as ast, AttrVec, BindingAnnotation, ByRef, Expr, ExprKind, MacCall, Mutability, Pat,
+    PatField, PatKind, Path, QSelf, RangeEnd, RangeSyntax,
 };
 use rustc_ast_pretty::pprust;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
@@ -320,7 +321,13 @@ impl<'a> Parser<'a> {
         maybe_recover_from_interpolated_ty_qpath!(self, true);
         maybe_whole!(self, NtPat, |x| x);
 
-        let lo = self.token.span;
+        let mut lo = self.token.span;
+
+        if self.token.is_keyword(kw::Let) && self.look_ahead(1, |tok| tok.can_begin_pattern()) {
+            self.bump();
+            self.sess.emit_err(RemoveLet { span: lo });
+            lo = self.token.span;
+        }
 
         let pat = if self.check(&token::BinOp(token::And)) || self.token.kind == token::AndAnd {
             self.parse_pat_deref(expected)?
@@ -353,7 +360,7 @@ impl<'a> Parser<'a> {
         } else if self.eat_keyword(kw::Ref) {
             // Parse ref ident @ pat / ref mut ident @ pat
             let mutbl = self.parse_mutability();
-            self.parse_pat_ident(BindingMode::ByRef(mutbl))?
+            self.parse_pat_ident(BindingAnnotation(ByRef::Yes, mutbl))?
         } else if self.eat_keyword(kw::Box) {
             self.parse_pat_box()?
         } else if self.check_inline_const(0) {
@@ -369,7 +376,7 @@ impl<'a> Parser<'a> {
             // Parse `ident @ pat`
             // This can give false positives and parse nullary enums,
             // they are dealt with later in resolve.
-            self.parse_pat_ident(BindingMode::ByValue(Mutability::Not))?
+            self.parse_pat_ident(BindingAnnotation::NONE)?
         } else if self.is_start_of_pat_with_path() {
             // Parse pattern starting with a path
             let (qself, path) = if self.eat_lt() {
@@ -578,7 +585,8 @@ impl<'a> Parser<'a> {
         let mut pat = self.parse_pat_no_top_alt(Some("identifier"))?;
 
         // If we don't have `mut $ident (@ pat)?`, error.
-        if let PatKind::Ident(BindingMode::ByValue(m @ Mutability::Not), ..) = &mut pat.kind {
+        if let PatKind::Ident(BindingAnnotation(ByRef::No, m @ Mutability::Not), ..) = &mut pat.kind
+        {
             // Don't recurse into the subpattern.
             // `mut` on the outer binding doesn't affect the inner bindings.
             *m = Mutability::Mut;
@@ -604,7 +612,7 @@ impl<'a> Parser<'a> {
             )
             .emit();
 
-        self.parse_pat_ident(BindingMode::ByRef(Mutability::Mut))
+        self.parse_pat_ident(BindingAnnotation::REF_MUT)
     }
 
     /// Turn all by-value immutable bindings in a pattern into mutable bindings.
@@ -613,7 +621,8 @@ impl<'a> Parser<'a> {
         struct AddMut(bool);
         impl MutVisitor for AddMut {
             fn visit_pat(&mut self, pat: &mut P<Pat>) {
-                if let PatKind::Ident(BindingMode::ByValue(m @ Mutability::Not), ..) = &mut pat.kind
+                if let PatKind::Ident(BindingAnnotation(ByRef::No, m @ Mutability::Not), ..) =
+                    &mut pat.kind
                 {
                     self.0 = true;
                     *m = Mutability::Mut;
@@ -838,7 +847,7 @@ impl<'a> Parser<'a> {
     /// Parses `ident` or `ident @ pat`.
     /// Used by the copy foo and ref foo patterns to give a good
     /// error message when parsing mistakes like `ref foo(a, b)`.
-    fn parse_pat_ident(&mut self, binding_mode: BindingMode) -> PResult<'a, PatKind> {
+    fn parse_pat_ident(&mut self, binding_annotation: BindingAnnotation) -> PResult<'a, PatKind> {
         let ident = self.parse_ident()?;
         let sub = if self.eat(&token::At) {
             Some(self.parse_pat_no_top_alt(Some("binding pattern"))?)
@@ -856,7 +865,7 @@ impl<'a> Parser<'a> {
                 .struct_span_err(self.prev_token.span, "expected identifier, found enum pattern"));
         }
 
-        Ok(PatKind::Ident(binding_mode, ident, sub))
+        Ok(PatKind::Ident(binding_annotation, ident, sub))
     }
 
     /// Parse a struct ("record") pattern (e.g. `Foo { ... }` or `Foo::Bar { ... }`).
@@ -936,11 +945,7 @@ impl<'a> Parser<'a> {
                 None
             };
 
-            Ok(PatKind::Ident(
-                BindingMode::ByValue(Mutability::Not),
-                Ident::new(kw::Box, box_span),
-                sub,
-            ))
+            Ok(PatKind::Ident(BindingAnnotation::NONE, Ident::new(kw::Box, box_span), sub))
         } else {
             let pat = self.parse_pat_with_range_pat(false, None)?;
             self.sess.gated_spans.gate(sym::box_patterns, box_span.to(self.prev_token.span));
@@ -1117,14 +1122,12 @@ impl<'a> Parser<'a> {
             let fieldname = self.parse_field_name()?;
             hi = self.prev_token.span;
 
-            let bind_type = match (is_ref, is_mut) {
-                (true, true) => BindingMode::ByRef(Mutability::Mut),
-                (true, false) => BindingMode::ByRef(Mutability::Not),
-                (false, true) => BindingMode::ByValue(Mutability::Mut),
-                (false, false) => BindingMode::ByValue(Mutability::Not),
+            let mutability = match is_mut {
+                false => Mutability::Not,
+                true => Mutability::Mut,
             };
-
-            let fieldpat = self.mk_pat_ident(boxed_span.to(hi), bind_type, fieldname);
+            let ann = BindingAnnotation(ByRef::from(is_ref), mutability);
+            let fieldpat = self.mk_pat_ident(boxed_span.to(hi), ann, fieldname);
             let subpat =
                 if is_box { self.mk_pat(lo.to(hi), PatKind::Box(fieldpat)) } else { fieldpat };
             (subpat, fieldname, true)
@@ -1141,8 +1144,8 @@ impl<'a> Parser<'a> {
         })
     }
 
-    pub(super) fn mk_pat_ident(&self, span: Span, bm: BindingMode, ident: Ident) -> P<Pat> {
-        self.mk_pat(span, PatKind::Ident(bm, ident, None))
+    pub(super) fn mk_pat_ident(&self, span: Span, ann: BindingAnnotation, ident: Ident) -> P<Pat> {
+        self.mk_pat(span, PatKind::Ident(ann, ident, None))
     }
 
     pub(super) fn mk_pat(&self, span: Span, kind: PatKind) -> P<Pat> {
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index fc7fb866f110..fdc1af27f82e 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -13,7 +13,6 @@ use rustc_span::source_map::{BytePos, Span};
 use rustc_span::symbol::{kw, sym, Ident};
 
 use std::mem;
-use tracing::debug;
 
 /// Specifies how to parse a path.
 #[derive(Copy, Clone, PartialEq)]
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 4a2cf74905bf..b47f0c097838 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -567,7 +567,8 @@ impl<'a> Parser<'a> {
         self.check_keyword(kw::Dyn)
             && (!self.token.uninterpolated_span().rust_2015()
                 || self.look_ahead(1, |t| {
-                    t.can_begin_bound() && !can_continue_type_after_non_fn_ident(t)
+                    (t.can_begin_bound() || t.kind == TokenKind::BinOp(token::Star))
+                        && !can_continue_type_after_non_fn_ident(t)
                 }))
     }
 
@@ -576,10 +577,18 @@ impl<'a> Parser<'a> {
     /// Note that this does *not* parse bare trait objects.
     fn parse_dyn_ty(&mut self, impl_dyn_multi: &mut bool) -> PResult<'a, TyKind> {
         self.bump(); // `dyn`
+
+        // parse dyn* types
+        let syntax = if self.eat(&TokenKind::BinOp(token::Star)) {
+            TraitObjectSyntax::DynStar
+        } else {
+            TraitObjectSyntax::Dyn
+        };
+
         // Always parse bounds greedily for better error recovery.
         let bounds = self.parse_generic_bounds(None)?;
         *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus);
-        Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn))
+        Ok(TyKind::TraitObject(bounds, syntax))
     }
 
     /// Parses a type starting with a path.
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index f376da29bd91..a21521ff68b1 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -11,9 +11,11 @@ use rustc_errors::{fluent, struct_span_err, Applicability, MultiSpan};
 use rustc_expand::base::resolve_path;
 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
 use rustc_hir as hir;
-use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
+use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::{self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID};
+use rustc_hir::{
+    self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID, CRATE_OWNER_ID,
+};
 use rustc_hir::{MethodKind, Target};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::resolve_lifetime::ObjectLifetimeDefault;
@@ -35,8 +37,8 @@ pub(crate) fn target_from_impl_item<'tcx>(
     match impl_item.kind {
         hir::ImplItemKind::Const(..) => Target::AssocConst,
         hir::ImplItemKind::Fn(..) => {
-            let parent_hir_id = tcx.hir().get_parent_item(impl_item.hir_id());
-            let containing_item = tcx.hir().expect_item(parent_hir_id);
+            let parent_def_id = tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
+            let containing_item = tcx.hir().expect_item(parent_def_id);
             let containing_impl_is_for_trait = match &containing_item.kind {
                 hir::ItemKind::Impl(impl_) => impl_.of_trait.is_some(),
                 _ => bug!("parent of an ImplItem must be an Impl"),
@@ -131,6 +133,7 @@ impl CheckAttrVisitor<'_> {
                 | sym::rustc_if_this_changed
                 | sym::rustc_then_this_would_need => self.check_rustc_dirty_clean(&attr),
                 sym::cmse_nonsecure_entry => self.check_cmse_nonsecure_entry(attr, span, target),
+                sym::collapse_debuginfo => self.check_collapse_debuginfo(attr, span, target),
                 sym::const_trait => self.check_const_trait(attr, span, target),
                 sym::must_not_suspend => self.check_must_not_suspend(&attr, span, target),
                 sym::must_use => self.check_must_use(hir_id, &attr, span, target),
@@ -173,9 +176,7 @@ impl CheckAttrVisitor<'_> {
                 sym::no_implicit_prelude => {
                     self.check_generic_attr(hir_id, attr, target, &[Target::Mod])
                 }
-                sym::rustc_object_lifetime_default => {
-                    self.check_object_lifetime_default(hir_id, span)
-                }
+                sym::rustc_object_lifetime_default => self.check_object_lifetime_default(hir_id),
                 _ => {}
             }
 
@@ -415,26 +416,34 @@ impl CheckAttrVisitor<'_> {
     }
 
     /// Debugging aid for `object_lifetime_default` query.
-    fn check_object_lifetime_default(&self, hir_id: HirId, span: Span) {
+    fn check_object_lifetime_default(&self, hir_id: HirId) {
         let tcx = self.tcx;
         if let Some(generics) = tcx.hir().get_generics(tcx.hir().local_def_id(hir_id)) {
-            let object_lifetime_default_reprs: String = generics
-                .params
-                .iter()
-                .filter_map(|p| {
-                    let param_id = tcx.hir().local_def_id(p.hir_id);
-                    let default = tcx.object_lifetime_default(param_id)?;
-                    Some(match default {
-                        ObjectLifetimeDefault::Empty => "BaseDefault".to_owned(),
-                        ObjectLifetimeDefault::Static => "'static".to_owned(),
-                        ObjectLifetimeDefault::Param(def_id) => tcx.item_name(def_id).to_string(),
-                        ObjectLifetimeDefault::Ambiguous => "Ambiguous".to_owned(),
-                    })
-                })
-                .collect::<Vec<String>>()
-                .join(",");
+            for p in generics.params {
+                let hir::GenericParamKind::Type { .. } = p.kind else { continue };
+                let param_id = tcx.hir().local_def_id(p.hir_id);
+                let default = tcx.object_lifetime_default(param_id);
+                let repr = match default {
+                    ObjectLifetimeDefault::Empty => "BaseDefault".to_owned(),
+                    ObjectLifetimeDefault::Static => "'static".to_owned(),
+                    ObjectLifetimeDefault::Param(def_id) => tcx.item_name(def_id).to_string(),
+                    ObjectLifetimeDefault::Ambiguous => "Ambiguous".to_owned(),
+                };
+                tcx.sess.span_err(p.span, &repr);
+            }
+        }
+    }
 
-            tcx.sess.span_err(span, &object_lifetime_default_reprs);
+    /// Checks if `#[collapse_debuginfo]` is applied to a macro.
+    fn check_collapse_debuginfo(&self, attr: &Attribute, span: Span, target: Target) -> bool {
+        match target {
+            Target::MacroDef => true,
+            _ => {
+                self.tcx
+                    .sess
+                    .emit_err(errors::CollapseDebuginfo { attr_span: attr.span, defn_span: span });
+                false
+            }
         }
     }
 
@@ -633,8 +642,8 @@ impl CheckAttrVisitor<'_> {
         let span = meta.span();
         if let Some(location) = match target {
             Target::AssocTy => {
-                let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
-                let containing_item = self.tcx.hir().expect_item(parent_hir_id);
+                let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
+                let containing_item = self.tcx.hir().expect_item(parent_def_id);
                 if Target::from_item(containing_item) == Target::Impl {
                     Some("type alias in implementation block")
                 } else {
@@ -642,8 +651,8 @@ impl CheckAttrVisitor<'_> {
                 }
             }
             Target::AssocConst => {
-                let parent_hir_id = self.tcx.hir().get_parent_item(hir_id);
-                let containing_item = self.tcx.hir().expect_item(parent_hir_id);
+                let parent_def_id = self.tcx.hir().get_parent_item(hir_id).def_id;
+                let containing_item = self.tcx.hir().expect_item(parent_def_id);
                 // We can't link to trait impl's consts.
                 let err = "associated constant in trait implementation block";
                 match containing_item.kind {
@@ -668,6 +677,7 @@ impl CheckAttrVisitor<'_> {
             | Target::GlobalAsm
             | Target::TyAlias
             | Target::OpaqueTy
+            | Target::ImplTraitPlaceholder
             | Target::Enum
             | Target::Variant
             | Target::Struct
@@ -870,7 +880,7 @@ impl CheckAttrVisitor<'_> {
             self.tcx.struct_span_lint_hir(INVALID_DOC_ATTRIBUTES, hir_id, meta.span(), |lint| {
                 let mut err = lint.build(fluent::passes::attr_crate_level);
                 if attr.style == AttrStyle::Outer
-                    && self.tcx.hir().get_parent_item(hir_id) == CRATE_DEF_ID
+                    && self.tcx.hir().get_parent_item(hir_id) == CRATE_OWNER_ID
                 {
                     if let Ok(mut src) = self.tcx.sess.source_map().span_to_snippet(attr.span) {
                         src.insert(1, '!');
@@ -1658,6 +1668,8 @@ impl CheckAttrVisitor<'_> {
                         E0552,
                         "unrecognized representation hint"
                     )
+                    .help("valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, \
+                          `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`")
                     .emit();
 
                     continue;
@@ -2145,6 +2157,7 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
         sym::automatically_derived,
         sym::start,
         sym::rustc_main,
+        sym::unix_sigpipe,
         sym::derive,
         sym::test,
         sym::test_case,
diff --git a/compiler/rustc_passes/src/check_const.rs b/compiler/rustc_passes/src/check_const.rs
index 70518284cf91..4062862ad747 100644
--- a/compiler/rustc_passes/src/check_const.rs
+++ b/compiler/rustc_passes/src/check_const.rs
@@ -192,6 +192,28 @@ impl<'tcx> Visitor<'tcx> for CheckConstVisitor<'tcx> {
     }
 
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
+        let tcx = self.tcx;
+        if let hir::ItemKind::Impl(hir::Impl {
+            constness: hir::Constness::Const,
+            of_trait: Some(trait_ref),
+            ..
+        }) = item.kind
+        {
+            let def_id = trait_ref.trait_def_id().unwrap();
+            let source_map = tcx.sess.source_map();
+            if !tcx.has_attr(def_id, sym::const_trait) {
+                tcx.sess
+                    .struct_span_err(
+                        source_map.guess_head_span(item.span),
+                        "const `impl`s must be for traits marked with `#[const_trait]`",
+                    )
+                    .span_note(
+                        source_map.guess_head_span(tcx.def_span(def_id)),
+                        "this trait must be annotated with `#[const_trait]`",
+                    )
+                    .emit();
+            }
+        }
         intravisit::walk_item(self, item);
     }
 
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index 625c854ea77a..e9d71bc93ac1 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -11,7 +11,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{Node, PatKind, TyKind};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
-use rustc_middle::middle::privacy;
+use rustc_middle::middle::privacy::AccessLevel;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_session::lint;
@@ -226,19 +226,16 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
         lhs: &hir::Pat<'_>,
         res: Res,
         pats: &[hir::Pat<'_>],
-        dotdot: Option<usize>,
+        dotdot: hir::DotDotPos,
     ) {
         let variant = match self.typeck_results().node_type(lhs.hir_id).kind() {
             ty::Adt(adt, _) => adt.variant_of_res(res),
             _ => span_bug!(lhs.span, "non-ADT in tuple struct pattern"),
         };
-        let first_n = pats.iter().enumerate().take(dotdot.unwrap_or(pats.len()));
+        let dotdot = dotdot.as_opt_usize().unwrap_or(pats.len());
+        let first_n = pats.iter().enumerate().take(dotdot);
         let missing = variant.fields.len() - pats.len();
-        let last_n = pats
-            .iter()
-            .enumerate()
-            .skip(dotdot.unwrap_or(pats.len()))
-            .map(|(idx, pat)| (idx + missing, pat));
+        let last_n = pats.iter().enumerate().skip(dotdot).map(|(idx, pat)| (idx + missing, pat));
         for (idx, pat) in first_n.chain(last_n) {
             if let PatKind::Wild = pat.kind {
                 continue;
@@ -320,7 +317,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                 intravisit::walk_trait_item(self, trait_item);
             }
             Node::ImplItem(impl_item) => {
-                let item = self.tcx.local_parent(impl_item.def_id);
+                let item = self.tcx.local_parent(impl_item.def_id.def_id);
                 if self.tcx.impl_trait_ref(item).is_none() {
                     //// If it's a type whose items are live, then it's live, too.
                     //// This is done to handle the case where, for example, the static
@@ -377,7 +374,7 @@ impl<'tcx> Visitor<'tcx> for MarkSymbolVisitor<'tcx> {
             if has_repr_c || (f.is_positional() && has_repr_simd) {
                 return Some(def_id);
             }
-            if !tcx.visibility(f.hir_id.owner).is_public() {
+            if !tcx.visibility(f.hir_id.owner.def_id).is_public() {
                 return None;
             }
             if tcx.visibility(def_id).is_public() { Some(def_id) } else { None }
@@ -450,7 +447,7 @@ impl<'tcx> Visitor<'tcx> for MarkSymbolVisitor<'tcx> {
     }
 
     fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
-        if let TyKind::OpaqueDef(item_id, _) = ty.kind {
+        if let TyKind::OpaqueDef(item_id, _, _) = ty.kind {
             let item = self.tcx.hir().item(item_id);
             intravisit::walk_item(self, item);
         }
@@ -531,7 +528,7 @@ fn check_item<'tcx>(
 ) {
     let allow_dead_code = has_allow_dead_code_or_lang_attr(tcx, id.hir_id());
     if allow_dead_code {
-        worklist.push(id.def_id);
+        worklist.push(id.def_id.def_id);
     }
 
     match tcx.def_kind(id.def_id) {
@@ -557,7 +554,7 @@ fn check_item<'tcx>(
             let of_trait = tcx.impl_trait_ref(id.def_id);
 
             if of_trait.is_some() {
-                worklist.push(id.def_id);
+                worklist.push(id.def_id.def_id);
             }
 
             // get DefIds from another query
@@ -580,12 +577,12 @@ fn check_item<'tcx>(
             if let hir::ItemKind::Struct(ref variant_data, _) = item.kind
                 && let Some(ctor_hir_id) = variant_data.ctor_hir_id()
             {
-                struct_constructors.insert(tcx.hir().local_def_id(ctor_hir_id), item.def_id);
+                struct_constructors.insert(tcx.hir().local_def_id(ctor_hir_id), item.def_id.def_id);
             }
         }
         DefKind::GlobalAsm => {
             // global_asm! is always live.
-            worklist.push(id.def_id);
+            worklist.push(id.def_id.def_id);
         }
         _ => {}
     }
@@ -598,7 +595,7 @@ fn check_trait_item<'tcx>(tcx: TyCtxt<'tcx>, worklist: &mut Vec<LocalDefId>, id:
         if matches!(trait_item.kind, Const(_, Some(_)) | Fn(_, hir::TraitFn::Provided(_)))
             && has_allow_dead_code_or_lang_attr(tcx, trait_item.hir_id())
         {
-            worklist.push(trait_item.def_id);
+            worklist.push(trait_item.def_id.def_id);
         }
     }
 }
@@ -611,7 +608,7 @@ fn check_foreign_item<'tcx>(
     if matches!(tcx.def_kind(id.def_id), DefKind::Static(_) | DefKind::Fn)
         && has_allow_dead_code_or_lang_attr(tcx, id.hir_id())
     {
-        worklist.push(id.def_id);
+        worklist.push(id.def_id.def_id);
     }
 }
 
@@ -622,13 +619,10 @@ fn create_and_seed_worklist<'tcx>(
     // see `MarkSymbolVisitor::struct_constructors`
     let mut struct_constructors = Default::default();
     let mut worklist = access_levels
-        .map
         .iter()
-        .filter_map(
-            |(&id, &level)| {
-                if level >= privacy::AccessLevel::Reachable { Some(id) } else { None }
-            },
-        )
+        .filter_map(|(&id, effective_vis)| {
+            effective_vis.is_public_at_level(AccessLevel::Reachable).then_some(id)
+        })
         // Seed entry point
         .chain(tcx.entry_fn(()).and_then(|(def_id, _)| def_id.as_local()))
         .collect::<Vec<_>>();
@@ -877,13 +871,13 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalDefId) {
     let module_items = tcx.hir_module_items(module);
 
     for item in module_items.items() {
-        if !live_symbols.contains(&item.def_id) {
-            let parent = tcx.local_parent(item.def_id);
+        if !live_symbols.contains(&item.def_id.def_id) {
+            let parent = tcx.local_parent(item.def_id.def_id);
             if parent != module && !live_symbols.contains(&parent) {
                 // We already have diagnosed something.
                 continue;
             }
-            visitor.check_definition(item.def_id);
+            visitor.check_definition(item.def_id.def_id);
             continue;
         }
 
@@ -932,16 +926,21 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalDefId) {
                 visitor.warn_dead_fields_and_variants(def_id, "read", dead_fields, is_positional)
             }
 
-            visitor.warn_dead_fields_and_variants(item.def_id, "constructed", dead_variants, false);
+            visitor.warn_dead_fields_and_variants(
+                item.def_id.def_id,
+                "constructed",
+                dead_variants,
+                false,
+            );
         }
     }
 
     for impl_item in module_items.impl_items() {
-        visitor.check_definition(impl_item.def_id);
+        visitor.check_definition(impl_item.def_id.def_id);
     }
 
     for foreign_item in module_items.foreign_items() {
-        visitor.check_definition(foreign_item.def_id);
+        visitor.check_definition(foreign_item.def_id.def_id);
     }
 
     // We do not warn trait items.
diff --git a/compiler/rustc_passes/src/diagnostic_items.rs b/compiler/rustc_passes/src/diagnostic_items.rs
index e6b69d8986cf..e428d9293db1 100644
--- a/compiler/rustc_passes/src/diagnostic_items.rs
+++ b/compiler/rustc_passes/src/diagnostic_items.rs
@@ -74,19 +74,19 @@ fn diagnostic_items<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> DiagnosticItems
     let crate_items = tcx.hir_crate_items(());
 
     for id in crate_items.items() {
-        observe_item(tcx, &mut diagnostic_items, id.def_id);
+        observe_item(tcx, &mut diagnostic_items, id.def_id.def_id);
     }
 
     for id in crate_items.trait_items() {
-        observe_item(tcx, &mut diagnostic_items, id.def_id);
+        observe_item(tcx, &mut diagnostic_items, id.def_id.def_id);
     }
 
     for id in crate_items.impl_items() {
-        observe_item(tcx, &mut diagnostic_items, id.def_id);
+        observe_item(tcx, &mut diagnostic_items, id.def_id.def_id);
     }
 
     for id in crate_items.foreign_items() {
-        observe_item(tcx, &mut diagnostic_items, id.def_id);
+        observe_item(tcx, &mut diagnostic_items, id.def_id.def_id);
     }
 
     diagnostic_items
diff --git a/compiler/rustc_passes/src/entry.rs b/compiler/rustc_passes/src/entry.rs
index 7381019a6201..eec37d19a883 100644
--- a/compiler/rustc_passes/src/entry.rs
+++ b/compiler/rustc_passes/src/entry.rs
@@ -1,11 +1,11 @@
-use rustc_ast::{entry::EntryPointType, Attribute};
+use rustc_ast::entry::EntryPointType;
 use rustc_errors::struct_span_err;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::{ItemId, Node, CRATE_HIR_ID};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{DefIdTree, TyCtxt};
-use rustc_session::config::{CrateType, EntryFnType};
+use rustc_session::config::{sigpipe, CrateType, EntryFnType};
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol, DUMMY_SP};
@@ -71,35 +71,35 @@ fn entry_point_type(ctxt: &EntryContext<'_>, id: ItemId, at_root: bool) -> Entry
     }
 }
 
-fn err_if_attr_found(ctxt: &EntryContext<'_>, attrs: &[Attribute], sym: Symbol) {
+fn err_if_attr_found(ctxt: &EntryContext<'_>, id: ItemId, sym: Symbol, details: &str) {
+    let attrs = ctxt.tcx.hir().attrs(id.hir_id());
     if let Some(attr) = ctxt.tcx.sess.find_by_name(attrs, sym) {
         ctxt.tcx
             .sess
-            .struct_span_err(
-                attr.span,
-                &format!("`{}` attribute can only be used on functions", sym),
-            )
+            .struct_span_err(attr.span, &format!("`{}` attribute {}", sym, details))
             .emit();
     }
 }
 
 fn find_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
-    let at_root = ctxt.tcx.opt_local_parent(id.def_id) == Some(CRATE_DEF_ID);
+    let at_root = ctxt.tcx.opt_local_parent(id.def_id.def_id) == Some(CRATE_DEF_ID);
 
     match entry_point_type(ctxt, id, at_root) {
-        EntryPointType::None => (),
+        EntryPointType::None => {
+            err_if_attr_found(ctxt, id, sym::unix_sigpipe, "can only be used on `fn main()`");
+        }
         _ if !matches!(ctxt.tcx.def_kind(id.def_id), DefKind::Fn) => {
-            let attrs = ctxt.tcx.hir().attrs(id.hir_id());
-            err_if_attr_found(ctxt, attrs, sym::start);
-            err_if_attr_found(ctxt, attrs, sym::rustc_main);
+            err_if_attr_found(ctxt, id, sym::start, "can only be used on functions");
+            err_if_attr_found(ctxt, id, sym::rustc_main, "can only be used on functions");
         }
         EntryPointType::MainNamed => (),
         EntryPointType::OtherMain => {
+            err_if_attr_found(ctxt, id, sym::unix_sigpipe, "can only be used on root `fn main()`");
             ctxt.non_main_fns.push(ctxt.tcx.def_span(id.def_id));
         }
         EntryPointType::RustcMainAttr => {
             if ctxt.attr_main_fn.is_none() {
-                ctxt.attr_main_fn = Some((id.def_id, ctxt.tcx.def_span(id.def_id.to_def_id())));
+                ctxt.attr_main_fn = Some((id.def_id.def_id, ctxt.tcx.def_span(id.def_id)));
             } else {
                 struct_span_err!(
                     ctxt.tcx.sess,
@@ -116,12 +116,13 @@ fn find_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
             }
         }
         EntryPointType::Start => {
+            err_if_attr_found(ctxt, id, sym::unix_sigpipe, "can only be used on `fn main()`");
             if ctxt.start_fn.is_none() {
-                ctxt.start_fn = Some((id.def_id, ctxt.tcx.def_span(id.def_id.to_def_id())));
+                ctxt.start_fn = Some((id.def_id.def_id, ctxt.tcx.def_span(id.def_id)));
             } else {
                 struct_span_err!(
                     ctxt.tcx.sess,
-                    ctxt.tcx.def_span(id.def_id.to_def_id()),
+                    ctxt.tcx.def_span(id.def_id),
                     E0138,
                     "multiple `start` functions"
                 )
@@ -136,8 +137,9 @@ fn find_item(id: ItemId, ctxt: &mut EntryContext<'_>) {
 fn configure_main(tcx: TyCtxt<'_>, visitor: &EntryContext<'_>) -> Option<(DefId, EntryFnType)> {
     if let Some((def_id, _)) = visitor.start_fn {
         Some((def_id.to_def_id(), EntryFnType::Start))
-    } else if let Some((def_id, _)) = visitor.attr_main_fn {
-        Some((def_id.to_def_id(), EntryFnType::Main))
+    } else if let Some((local_def_id, _)) = visitor.attr_main_fn {
+        let def_id = local_def_id.to_def_id();
+        Some((def_id, EntryFnType::Main { sigpipe: sigpipe(tcx, def_id) }))
     } else {
         if let Some(main_def) = tcx.resolutions(()).main_def && let Some(def_id) = main_def.opt_fn_def_id() {
             // non-local main imports are handled below
@@ -161,13 +163,39 @@ fn configure_main(tcx: TyCtxt<'_>, visitor: &EntryContext<'_>) -> Option<(DefId,
                 )
                 .emit();
             }
-            return Some((def_id, EntryFnType::Main));
+            return Some((def_id, EntryFnType::Main { sigpipe: sigpipe(tcx, def_id) }));
         }
         no_main_err(tcx, visitor);
         None
     }
 }
 
+fn sigpipe(tcx: TyCtxt<'_>, def_id: DefId) -> u8 {
+    if let Some(attr) = tcx.get_attr(def_id, sym::unix_sigpipe) {
+        match (attr.value_str(), attr.meta_item_list()) {
+            (Some(sym::inherit), None) => sigpipe::INHERIT,
+            (Some(sym::sig_ign), None) => sigpipe::SIG_IGN,
+            (Some(sym::sig_dfl), None) => sigpipe::SIG_DFL,
+            (_, Some(_)) => {
+                // Keep going so that `fn emit_malformed_attribute()` can print
+                // an excellent error message
+                sigpipe::DEFAULT
+            }
+            _ => {
+                tcx.sess
+                    .struct_span_err(
+                        attr.span,
+                        "valid values for `#[unix_sigpipe = \"...\"]` are `inherit`, `sig_ign`, or `sig_dfl`",
+                    )
+                    .emit();
+                sigpipe::DEFAULT
+            }
+        }
+    } else {
+        sigpipe::DEFAULT
+    }
+}
+
 fn no_main_err(tcx: TyCtxt<'_>, visitor: &EntryContext<'_>) {
     let sp = tcx.def_span(CRATE_DEF_ID);
     if *tcx.sess.parse_sess.reached_eof.borrow() {
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 901f56ad96d1..cc231af71a27 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1,5 +1,5 @@
 use rustc_errors::{Applicability, MultiSpan};
-use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
 #[derive(LintDiagnostic)]
@@ -32,7 +32,7 @@ pub struct IgnoredInlineAttrFnProto;
 #[note]
 pub struct IgnoredInlineAttrConstants;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::inline_not_fn_or_closure, code = "E0518")]
 pub struct InlineNotFnOrClosure {
     #[primary_span]
@@ -53,7 +53,7 @@ pub struct IgnoredNoCoveragePropagate;
 #[diag(passes::no_coverage_fn_defn)]
 pub struct IgnoredNoCoverageFnDefn;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::no_coverage_not_coverable, code = "E0788")]
 pub struct IgnoredNoCoverageNotCoverable {
     #[primary_span]
@@ -62,7 +62,7 @@ pub struct IgnoredNoCoverageNotCoverable {
     pub defn_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::should_be_applied_to_fn)]
 pub struct AttrShouldBeAppliedToFn {
     #[primary_span]
@@ -71,14 +71,14 @@ pub struct AttrShouldBeAppliedToFn {
     pub defn_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::naked_tracked_caller, code = "E0736")]
 pub struct NakedTrackedCaller {
     #[primary_span]
     pub attr_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::should_be_applied_to_fn, code = "E0739")]
 pub struct TrackedCallerWrongLocation {
     #[primary_span]
@@ -87,7 +87,7 @@ pub struct TrackedCallerWrongLocation {
     pub defn_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::should_be_applied_to_struct_enum, code = "E0701")]
 pub struct NonExhaustiveWrongLocation {
     #[primary_span]
@@ -96,7 +96,7 @@ pub struct NonExhaustiveWrongLocation {
     pub defn_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::should_be_applied_to_trait)]
 pub struct AttrShouldBeAppliedToTrait {
     #[primary_span]
@@ -109,7 +109,7 @@ pub struct AttrShouldBeAppliedToTrait {
 #[diag(passes::target_feature_on_statement)]
 pub struct TargetFeatureOnStatement;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::should_be_applied_to_static)]
 pub struct AttrShouldBeAppliedToStatic {
     #[primary_span]
@@ -118,7 +118,7 @@ pub struct AttrShouldBeAppliedToStatic {
     pub defn_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_expect_str)]
 pub struct DocExpectStr<'a> {
     #[primary_span]
@@ -126,7 +126,7 @@ pub struct DocExpectStr<'a> {
     pub attr_name: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_empty)]
 pub struct DocAliasEmpty<'a> {
     #[primary_span]
@@ -134,7 +134,7 @@ pub struct DocAliasEmpty<'a> {
     pub attr_str: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_bad_char)]
 pub struct DocAliasBadChar<'a> {
     #[primary_span]
@@ -143,7 +143,7 @@ pub struct DocAliasBadChar<'a> {
     pub char_: char,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_start_end)]
 pub struct DocAliasStartEnd<'a> {
     #[primary_span]
@@ -151,7 +151,7 @@ pub struct DocAliasStartEnd<'a> {
     pub attr_str: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_bad_location)]
 pub struct DocAliasBadLocation<'a> {
     #[primary_span]
@@ -160,7 +160,7 @@ pub struct DocAliasBadLocation<'a> {
     pub location: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_not_an_alias)]
 pub struct DocAliasNotAnAlias<'a> {
     #[primary_span]
@@ -175,35 +175,35 @@ pub struct DocAliasDuplicated {
     pub first_defn: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_not_string_literal)]
 pub struct DocAliasNotStringLiteral {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_alias_malformed)]
 pub struct DocAliasMalformed {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_keyword_empty_mod)]
 pub struct DocKeywordEmptyMod {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_keyword_not_mod)]
 pub struct DocKeywordNotMod {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_keyword_invalid_ident)]
 pub struct DocKeywordInvalidIdent {
     #[primary_span]
@@ -211,21 +211,21 @@ pub struct DocKeywordInvalidIdent {
     pub doc_keyword: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_fake_variadic_not_valid)]
 pub struct DocFakeVariadicNotValid {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_keyword_only_impl)]
 pub struct DocKeywordOnlyImpl {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_inline_conflict)]
 #[help]
 pub struct DocKeywordConflict {
@@ -243,7 +243,7 @@ pub struct DocInlineOnlyUse {
     pub item_span: Option<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::doc_attr_not_crate_level)]
 pub struct DocAttrNotCrateLevel<'a> {
     #[primary_span]
@@ -295,7 +295,7 @@ pub struct DocTestUnknownInclude {
 #[diag(passes::doc_invalid)]
 pub struct DocInvalid;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::pass_by_value)]
 pub struct PassByValue {
     #[primary_span]
@@ -304,7 +304,7 @@ pub struct PassByValue {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::allow_incoherent_impl)]
 pub struct AllowIncoherentImpl {
     #[primary_span]
@@ -313,7 +313,7 @@ pub struct AllowIncoherentImpl {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::has_incoherent_inherent_impl)]
 pub struct HasIncoherentInherentImpl {
     #[primary_span]
@@ -336,7 +336,7 @@ pub struct MustUseNoEffect {
     pub target: rustc_hir::Target,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::must_not_suspend)]
 pub struct MustNotSuspend {
     #[primary_span]
@@ -372,7 +372,7 @@ pub struct LinkName<'a> {
     pub value: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::no_link)]
 pub struct NoLink {
     #[primary_span]
@@ -381,7 +381,7 @@ pub struct NoLink {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::export_name)]
 pub struct ExportName {
     #[primary_span]
@@ -390,7 +390,7 @@ pub struct ExportName {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_layout_scalar_valid_range_not_struct)]
 pub struct RustcLayoutScalarValidRangeNotStruct {
     #[primary_span]
@@ -399,14 +399,14 @@ pub struct RustcLayoutScalarValidRangeNotStruct {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_layout_scalar_valid_range_arg)]
 pub struct RustcLayoutScalarValidRangeArg {
     #[primary_span]
     pub attr_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_legacy_const_generics_only)]
 pub struct RustcLegacyConstGenericsOnly {
     #[primary_span]
@@ -415,7 +415,7 @@ pub struct RustcLegacyConstGenericsOnly {
     pub param_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_legacy_const_generics_index)]
 pub struct RustcLegacyConstGenericsIndex {
     #[primary_span]
@@ -424,7 +424,7 @@ pub struct RustcLegacyConstGenericsIndex {
     pub generics_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_legacy_const_generics_index_exceed)]
 pub struct RustcLegacyConstGenericsIndexExceed {
     #[primary_span]
@@ -433,14 +433,14 @@ pub struct RustcLegacyConstGenericsIndexExceed {
     pub arg_count: usize,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_legacy_const_generics_index_negative)]
 pub struct RustcLegacyConstGenericsIndexNegative {
     #[primary_span]
     pub invalid_args: Vec<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_dirty_clean)]
 pub struct RustcDirtyClean {
     #[primary_span]
@@ -462,7 +462,7 @@ pub struct LinkSection {
 pub struct NoMangleForeign {
     #[label]
     pub span: Span,
-    #[suggestion(applicability = "machine-applicable")]
+    #[suggestion(code = "", applicability = "machine-applicable")]
     pub attr_span: Span,
     pub foreign_item_kind: &'static str,
 }
@@ -475,7 +475,7 @@ pub struct NoMangle {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::repr_ident, code = "E0565")]
 pub struct ReprIdent {
     #[primary_span]
@@ -486,21 +486,21 @@ pub struct ReprIdent {
 #[diag(passes::repr_conflicting, code = "E0566")]
 pub struct ReprConflicting;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::used_static)]
 pub struct UsedStatic {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::used_compiler_linker)]
 pub struct UsedCompilerLinker {
     #[primary_span]
     pub spans: Vec<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::allow_internal_unstable)]
 pub struct AllowInternalUnstable {
     #[primary_span]
@@ -509,14 +509,14 @@ pub struct AllowInternalUnstable {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::debug_visualizer_placement)]
 pub struct DebugVisualizerPlacement {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::debug_visualizer_invalid)]
 #[note(passes::note_1)]
 #[note(passes::note_2)]
@@ -526,7 +526,7 @@ pub struct DebugVisualizerInvalid {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_allow_const_fn_unstable)]
 pub struct RustcAllowConstFnUnstable {
     #[primary_span]
@@ -535,7 +535,7 @@ pub struct RustcAllowConstFnUnstable {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_std_internal_symbol)]
 pub struct RustcStdInternalSymbol {
     #[primary_span]
@@ -544,21 +544,21 @@ pub struct RustcStdInternalSymbol {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::const_trait)]
 pub struct ConstTrait {
     #[primary_span]
     pub attr_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::link_ordinal)]
 pub struct LinkOrdinal {
     #[primary_span]
     pub attr_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::stability_promotable)]
 pub struct StabilityPromotable {
     #[primary_span]
@@ -583,7 +583,7 @@ pub struct MacroExport;
 #[diag(passes::plugin_registrar)]
 pub struct PluginRegistrar;
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum UnusedNote {
     #[note(passes::unused_empty_lints_note)]
     EmptyList { name: Symbol },
@@ -596,13 +596,13 @@ pub enum UnusedNote {
 #[derive(LintDiagnostic)]
 #[diag(passes::unused)]
 pub struct Unused {
-    #[suggestion(applicability = "machine-applicable")]
+    #[suggestion(code = "", applicability = "machine-applicable")]
     pub attr_span: Span,
     #[subdiagnostic]
     pub note: UnusedNote,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::non_exported_macro_invalid_attrs, code = "E0518")]
 pub struct NonExportedMacroInvalidAttrs {
     #[primary_span]
@@ -621,7 +621,7 @@ pub struct UnusedDuplicate {
     pub warning: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::unused_multiple)]
 pub struct UnusedMultiple {
     #[primary_span]
@@ -632,7 +632,7 @@ pub struct UnusedMultiple {
     pub name: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_lint_opt_ty)]
 pub struct RustcLintOptTy {
     #[primary_span]
@@ -641,7 +641,7 @@ pub struct RustcLintOptTy {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(passes::rustc_lint_opt_deny_field_access)]
 pub struct RustcLintOptDenyFieldAccess {
     #[primary_span]
@@ -649,3 +649,19 @@ pub struct RustcLintOptDenyFieldAccess {
     #[label]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(passes::collapse_debuginfo)]
+pub struct CollapseDebuginfo {
+    #[primary_span]
+    pub attr_span: Span,
+    #[label]
+    pub defn_span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(passes::deprecated_annotation_has_no_effect)]
+pub struct DeprecatedAnnotationHasNoEffect {
+    #[suggestion(applicability = "machine-applicable", code = "")]
+    pub span: Span,
+}
diff --git a/compiler/rustc_passes/src/hir_id_validator.rs b/compiler/rustc_passes/src/hir_id_validator.rs
index 212ea9e57a37..3ee8c8bcb1de 100644
--- a/compiler/rustc_passes/src/hir_id_validator.rs
+++ b/compiler/rustc_passes/src/hir_id_validator.rs
@@ -1,6 +1,5 @@
 use rustc_data_structures::sync::Lock;
 use rustc_hir as hir;
-use rustc_hir::def_id::{LocalDefId, CRATE_DEF_ID};
 use rustc_hir::intravisit;
 use rustc_hir::{HirId, ItemLocalId};
 use rustc_index::bit_set::GrowableBitSet;
@@ -42,7 +41,7 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
 
 struct HirIdValidator<'a, 'hir> {
     hir_map: Map<'hir>,
-    owner: Option<LocalDefId>,
+    owner: Option<hir::OwnerId>,
     hir_ids_seen: GrowableBitSet<ItemLocalId>,
     errors: &'a Lock<Vec<String>>,
 }
@@ -63,12 +62,12 @@ impl<'a, 'hir> HirIdValidator<'a, 'hir> {
         self.errors.lock().push(f());
     }
 
-    fn check<F: FnOnce(&mut HirIdValidator<'a, 'hir>)>(&mut self, owner: LocalDefId, walk: F) {
+    fn check<F: FnOnce(&mut HirIdValidator<'a, 'hir>)>(&mut self, owner: hir::OwnerId, walk: F) {
         assert!(self.owner.is_none());
         self.owner = Some(owner);
         walk(self);
 
-        if owner == CRATE_DEF_ID {
+        if owner == hir::CRATE_OWNER_ID {
             return;
         }
 
@@ -97,14 +96,14 @@ impl<'a, 'hir> HirIdValidator<'a, 'hir> {
                 missing_items.push(format!(
                     "[local_id: {}, owner: {}]",
                     local_id,
-                    self.hir_map.def_path(owner).to_string_no_crate_verbose()
+                    self.hir_map.def_path(owner.def_id).to_string_no_crate_verbose()
                 ));
             }
             self.error(|| {
                 format!(
                     "ItemLocalIds not assigned densely in {}. \
-                Max ItemLocalId = {}, missing IDs = {:?}; seens IDs = {:?}",
-                    self.hir_map.def_path(owner).to_string_no_crate_verbose(),
+                Max ItemLocalId = {}, missing IDs = {:#?}; seens IDs = {:#?}",
+                    self.hir_map.def_path(owner.def_id).to_string_no_crate_verbose(),
                     max,
                     missing_items,
                     self.hir_ids_seen
@@ -138,8 +137,8 @@ impl<'a, 'hir> intravisit::Visitor<'hir> for HirIdValidator<'a, 'hir> {
                 format!(
                     "HirIdValidator: The recorded owner of {} is {} instead of {}",
                     self.hir_map.node_to_string(hir_id),
-                    self.hir_map.def_path(hir_id.owner).to_string_no_crate_verbose(),
-                    self.hir_map.def_path(owner).to_string_no_crate_verbose()
+                    self.hir_map.def_path(hir_id.owner.def_id).to_string_no_crate_verbose(),
+                    self.hir_map.def_path(owner.def_id).to_string_no_crate_verbose()
                 )
             });
         }
diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
index 399d00b403a6..0be2fc053446 100644
--- a/compiler/rustc_passes/src/hir_stats.rs
+++ b/compiler/rustc_passes/src/hir_stats.rs
@@ -49,7 +49,7 @@ impl Node {
 ///
 /// For example, `ast::Visitor` has `visit_ident`, but `Ident`s are always
 /// stored inline within other AST nodes, so we don't implement `visit_ident`
-/// here. In constrast, we do implement `visit_expr` because `ast::Expr` is
+/// here. In contrast, we do implement `visit_expr` because `ast::Expr` is
 /// always stored as `P<ast::Expr>`, and every such expression should be
 /// measured separately.
 ///
@@ -74,16 +74,16 @@ pub fn print_hir_stats(tcx: TyCtxt<'_>) {
     };
     tcx.hir().walk_toplevel_module(&mut collector);
     tcx.hir().walk_attributes(&mut collector);
-    collector.print("HIR STATS");
+    collector.print("HIR STATS", "hir-stats");
 }
 
-pub fn print_ast_stats(krate: &ast::Crate, title: &str) {
+pub fn print_ast_stats(krate: &ast::Crate, title: &str, prefix: &str) {
     use rustc_ast::visit::Visitor;
 
     let mut collector =
         StatCollector { krate: None, nodes: FxHashMap::default(), seen: FxHashSet::default() };
     collector.visit_crate(krate);
-    collector.print(title);
+    collector.print(title, prefix);
 }
 
 impl<'k> StatCollector<'k> {
@@ -119,23 +119,26 @@ impl<'k> StatCollector<'k> {
         }
     }
 
-    fn print(&self, title: &str) {
+    fn print(&self, title: &str, prefix: &str) {
         let mut nodes: Vec<_> = self.nodes.iter().collect();
         nodes.sort_by_key(|&(_, ref node)| node.stats.count * node.stats.size);
 
         let total_size = nodes.iter().map(|(_, node)| node.stats.count * node.stats.size).sum();
 
-        eprintln!("\n{}\n", title);
-
-        eprintln!("{:<18}{:>18}{:>14}{:>14}", "Name", "Accumulated Size", "Count", "Item Size");
-        eprintln!("----------------------------------------------------------------");
+        eprintln!("{} {}", prefix, title);
+        eprintln!(
+            "{} {:<18}{:>18}{:>14}{:>14}",
+            prefix, "Name", "Accumulated Size", "Count", "Item Size"
+        );
+        eprintln!("{} ----------------------------------------------------------------", prefix);
 
         let percent = |m, n| (m * 100) as f64 / n as f64;
 
         for (label, node) in nodes {
             let size = node.stats.count * node.stats.size;
             eprintln!(
-                "{:<18}{:>10} ({:4.1}%){:>14}{:>14}",
+                "{} {:<18}{:>10} ({:4.1}%){:>14}{:>14}",
+                prefix,
                 label,
                 to_readable_str(size),
                 percent(size, total_size),
@@ -149,7 +152,8 @@ impl<'k> StatCollector<'k> {
                 for (label, subnode) in subnodes {
                     let size = subnode.count * subnode.size;
                     eprintln!(
-                        "- {:<18}{:>10} ({:4.1}%){:>14}",
+                        "{} - {:<18}{:>10} ({:4.1}%){:>14}",
+                        prefix,
                         label,
                         to_readable_str(size),
                         percent(size, total_size),
@@ -158,11 +162,28 @@ impl<'k> StatCollector<'k> {
                 }
             }
         }
-        eprintln!("----------------------------------------------------------------");
-        eprintln!("{:<18}{:>10}\n", "Total", to_readable_str(total_size));
+        eprintln!("{} ----------------------------------------------------------------", prefix);
+        eprintln!("{} {:<18}{:>10}", prefix, "Total", to_readable_str(total_size));
+        eprintln!("{}", prefix);
     }
 }
 
+// Used to avoid boilerplate for types with many variants.
+macro_rules! record_variants {
+    (
+        ($self:ident, $val:expr, $kind:expr, $id:expr, $mod:ident, $ty:ty, $tykind:ident),
+        [$($variant:ident),*]
+    ) => {
+        match $kind {
+            $(
+                $mod::$tykind::$variant { .. } => {
+                    $self.record_variant(stringify!($ty), stringify!($variant), $id, $val)
+                }
+            )*
+        }
+    };
+}
+
 impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
     fn visit_param(&mut self, param: &'v hir::Param<'v>) {
         self.record("Param", Id::Node(param.hir_id), param);
@@ -195,12 +216,46 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
     }
 
     fn visit_item(&mut self, i: &'v hir::Item<'v>) {
-        self.record("Item", Id::Node(i.hir_id()), i);
+        record_variants!(
+            (self, i, i.kind, Id::Node(i.hir_id()), hir, Item, ItemKind),
+            [
+                ExternCrate,
+                Use,
+                Static,
+                Const,
+                Fn,
+                Macro,
+                Mod,
+                ForeignMod,
+                GlobalAsm,
+                TyAlias,
+                OpaqueTy,
+                Enum,
+                Struct,
+                Union,
+                Trait,
+                TraitAlias,
+                Impl
+            ]
+        );
         hir_visit::walk_item(self, i)
     }
 
+    fn visit_body(&mut self, b: &'v hir::Body<'v>) {
+        self.record("Body", Id::None, b);
+        hir_visit::walk_body(self, b);
+    }
+
+    fn visit_mod(&mut self, m: &'v hir::Mod<'v>, _s: Span, n: HirId) {
+        self.record("Mod", Id::None, m);
+        hir_visit::walk_mod(self, m, n)
+    }
+
     fn visit_foreign_item(&mut self, i: &'v hir::ForeignItem<'v>) {
-        self.record("ForeignItem", Id::Node(i.hir_id()), i);
+        record_variants!(
+            (self, i, i.kind, Id::Node(i.hir_id()), hir, ForeignItem, ForeignItemKind),
+            [Fn, Static, Type]
+        );
         hir_visit::walk_foreign_item(self, i)
     }
 
@@ -215,7 +270,10 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
     }
 
     fn visit_stmt(&mut self, s: &'v hir::Stmt<'v>) {
-        self.record("Stmt", Id::Node(s.hir_id), s);
+        record_variants!(
+            (self, s, s.kind, Id::Node(s.hir_id), hir, Stmt, StmtKind),
+            [Local, Item, Expr, Semi]
+        );
         hir_visit::walk_stmt(self, s)
     }
 
@@ -225,50 +283,135 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
     }
 
     fn visit_pat(&mut self, p: &'v hir::Pat<'v>) {
-        self.record("Pat", Id::Node(p.hir_id), p);
+        record_variants!(
+            (self, p, p.kind, Id::Node(p.hir_id), hir, Pat, PatKind),
+            [Wild, Binding, Struct, TupleStruct, Or, Path, Tuple, Box, Ref, Lit, Range, Slice]
+        );
         hir_visit::walk_pat(self, p)
     }
 
-    fn visit_expr(&mut self, ex: &'v hir::Expr<'v>) {
-        self.record("Expr", Id::Node(ex.hir_id), ex);
-        hir_visit::walk_expr(self, ex)
+    fn visit_pat_field(&mut self, f: &'v hir::PatField<'v>) {
+        self.record("PatField", Id::Node(f.hir_id), f);
+        hir_visit::walk_pat_field(self, f)
+    }
+
+    fn visit_expr(&mut self, e: &'v hir::Expr<'v>) {
+        record_variants!(
+            (self, e, e.kind, Id::Node(e.hir_id), hir, Expr, ExprKind),
+            [
+                Box, ConstBlock, Array, Call, MethodCall, Tup, Binary, Unary, Lit, Cast, Type,
+                DropTemps, Let, If, Loop, Match, Closure, Block, Assign, AssignOp, Field, Index,
+                Path, AddrOf, Break, Continue, Ret, InlineAsm, Struct, Repeat, Yield, Err
+            ]
+        );
+        hir_visit::walk_expr(self, e)
+    }
+
+    fn visit_let_expr(&mut self, lex: &'v hir::Let<'v>) {
+        self.record("Let", Id::Node(lex.hir_id), lex);
+        hir_visit::walk_let_expr(self, lex)
+    }
+
+    fn visit_expr_field(&mut self, f: &'v hir::ExprField<'v>) {
+        self.record("ExprField", Id::Node(f.hir_id), f);
+        hir_visit::walk_expr_field(self, f)
     }
 
     fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
-        self.record("Ty", Id::Node(t.hir_id), t);
+        record_variants!(
+            (self, t, t.kind, Id::Node(t.hir_id), hir, Ty, TyKind),
+            [
+                Slice,
+                Array,
+                Ptr,
+                Rptr,
+                BareFn,
+                Never,
+                Tup,
+                Path,
+                OpaqueDef,
+                TraitObject,
+                Typeof,
+                Infer,
+                Err
+            ]
+        );
         hir_visit::walk_ty(self, t)
     }
 
+    fn visit_generic_param(&mut self, p: &'v hir::GenericParam<'v>) {
+        self.record("GenericParam", Id::Node(p.hir_id), p);
+        hir_visit::walk_generic_param(self, p)
+    }
+
+    fn visit_generics(&mut self, g: &'v hir::Generics<'v>) {
+        self.record("Generics", Id::None, g);
+        hir_visit::walk_generics(self, g)
+    }
+
+    fn visit_where_predicate(&mut self, p: &'v hir::WherePredicate<'v>) {
+        record_variants!(
+            (self, p, p, Id::None, hir, WherePredicate, WherePredicate),
+            [BoundPredicate, RegionPredicate, EqPredicate]
+        );
+        hir_visit::walk_where_predicate(self, p)
+    }
+
     fn visit_fn(
         &mut self,
         fk: hir_visit::FnKind<'v>,
         fd: &'v hir::FnDecl<'v>,
         b: hir::BodyId,
-        s: Span,
+        _: Span,
         id: hir::HirId,
     ) {
         self.record("FnDecl", Id::None, fd);
-        hir_visit::walk_fn(self, fk, fd, b, s, id)
+        hir_visit::walk_fn(self, fk, fd, b, id)
     }
 
-    fn visit_where_predicate(&mut self, predicate: &'v hir::WherePredicate<'v>) {
-        self.record("WherePredicate", Id::None, predicate);
-        hir_visit::walk_where_predicate(self, predicate)
+    fn visit_use(&mut self, p: &'v hir::Path<'v>, hir_id: hir::HirId) {
+        // This is `visit_use`, but the type is `Path` so record it that way.
+        self.record("Path", Id::None, p);
+        hir_visit::walk_use(self, p, hir_id)
     }
 
     fn visit_trait_item(&mut self, ti: &'v hir::TraitItem<'v>) {
-        self.record("TraitItem", Id::Node(ti.hir_id()), ti);
+        record_variants!(
+            (self, ti, ti.kind, Id::Node(ti.hir_id()), hir, TraitItem, TraitItemKind),
+            [Const, Fn, Type]
+        );
         hir_visit::walk_trait_item(self, ti)
     }
 
+    fn visit_trait_item_ref(&mut self, ti: &'v hir::TraitItemRef) {
+        self.record("TraitItemRef", Id::Node(ti.id.hir_id()), ti);
+        hir_visit::walk_trait_item_ref(self, ti)
+    }
+
     fn visit_impl_item(&mut self, ii: &'v hir::ImplItem<'v>) {
-        self.record("ImplItem", Id::Node(ii.hir_id()), ii);
+        record_variants!(
+            (self, ii, ii.kind, Id::Node(ii.hir_id()), hir, ImplItem, ImplItemKind),
+            [Const, Fn, TyAlias]
+        );
         hir_visit::walk_impl_item(self, ii)
     }
 
-    fn visit_param_bound(&mut self, bounds: &'v hir::GenericBound<'v>) {
-        self.record("GenericBound", Id::None, bounds);
-        hir_visit::walk_param_bound(self, bounds)
+    fn visit_foreign_item_ref(&mut self, fi: &'v hir::ForeignItemRef) {
+        self.record("ForeignItemRef", Id::Node(fi.id.hir_id()), fi);
+        hir_visit::walk_foreign_item_ref(self, fi)
+    }
+
+    fn visit_impl_item_ref(&mut self, ii: &'v hir::ImplItemRef) {
+        self.record("ImplItemRef", Id::Node(ii.id.hir_id()), ii);
+        hir_visit::walk_impl_item_ref(self, ii)
+    }
+
+    fn visit_param_bound(&mut self, b: &'v hir::GenericBound<'v>) {
+        record_variants!(
+            (self, b, b, Id::None, hir, GenericBound, GenericBound),
+            [Trait, LangItemTrait, Outlives]
+        );
+        hir_visit::walk_param_bound(self, b)
     }
 
     fn visit_field_def(&mut self, s: &'v hir::FieldDef<'v>) {
@@ -281,28 +424,37 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
         hir_visit::walk_variant(self, v)
     }
 
+    fn visit_generic_arg(&mut self, ga: &'v hir::GenericArg<'v>) {
+        record_variants!(
+            (self, ga, ga, Id::Node(ga.hir_id()), hir, GenericArg, GenericArg),
+            [Lifetime, Type, Const, Infer]
+        );
+        match ga {
+            hir::GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
+            hir::GenericArg::Type(ty) => self.visit_ty(ty),
+            hir::GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
+            hir::GenericArg::Infer(inf) => self.visit_infer(inf),
+        }
+    }
+
     fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) {
         self.record("Lifetime", Id::Node(lifetime.hir_id), lifetime);
         hir_visit::walk_lifetime(self, lifetime)
     }
 
-    fn visit_qpath(&mut self, qpath: &'v hir::QPath<'v>, id: hir::HirId, span: Span) {
-        self.record("QPath", Id::None, qpath);
-        hir_visit::walk_qpath(self, qpath, id, span)
-    }
-
     fn visit_path(&mut self, path: &'v hir::Path<'v>, _id: hir::HirId) {
         self.record("Path", Id::None, path);
         hir_visit::walk_path(self, path)
     }
 
-    // `PathSegment` has one inline use (in `ast::ExprKind::MethodCall`) and
-    // one non-inline use (in `Path::segments`). The latter case is more common
-    // than the former case, so we implement this visitor and tolerate the
-    // double counting in the former case.
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v hir::PathSegment<'v>) {
+    fn visit_path_segment(&mut self, path_segment: &'v hir::PathSegment<'v>) {
         self.record("PathSegment", Id::None, path_segment);
-        hir_visit::walk_path_segment(self, path_span, path_segment)
+        hir_visit::walk_path_segment(self, path_segment)
+    }
+
+    fn visit_generic_args(&mut self, ga: &'v hir::GenericArgs<'v>) {
+        self.record("GenericArgs", Id::None, ga);
+        hir_visit::walk_generic_args(self, ga)
     }
 
     fn visit_assoc_type_binding(&mut self, type_binding: &'v hir::TypeBinding<'v>) {
@@ -313,28 +465,17 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
     fn visit_attribute(&mut self, attr: &'v ast::Attribute) {
         self.record("Attribute", Id::Attr(attr.id), attr);
     }
-}
 
-// Used to avoid boilerplate for types with many variants.
-macro_rules! record_variants {
-    (
-        ($self:ident, $val:expr, $kind:expr, $ty:ty, $tykind:ident), // mandatory pieces
-        [$($variant:ident),*]
-    ) => {
-        match $kind {
-            $(
-                ast::$tykind::$variant { .. } => {
-                    $self.record_variant(stringify!($ty), stringify!($variant), Id::None, $val)
-                }
-            )*
-        }
-    };
+    fn visit_inline_asm(&mut self, asm: &'v hir::InlineAsm<'v>, id: HirId) {
+        self.record("InlineAsm", Id::None, asm);
+        hir_visit::walk_inline_asm(self, asm, id);
+    }
 }
 
 impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
     fn visit_foreign_item(&mut self, i: &'v ast::ForeignItem) {
         record_variants!(
-            (self, i, i.kind, ForeignItem, ForeignItemKind),
+            (self, i, i.kind, Id::None, ast, ForeignItem, ForeignItemKind),
             [Static, Fn, TyAlias, MacCall]
         );
         ast_visit::walk_foreign_item(self, i)
@@ -342,7 +483,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_item(&mut self, i: &'v ast::Item) {
         record_variants!(
-            (self, i, i.kind, Item, ItemKind),
+            (self, i, i.kind, Id::None, ast, Item, ItemKind),
             [
                 ExternCrate,
                 Use,
@@ -378,7 +519,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_stmt(&mut self, s: &'v ast::Stmt) {
         record_variants!(
-            (self, s, s.kind, Stmt, StmtKind),
+            (self, s, s.kind, Id::None, ast, Stmt, StmtKind),
             [Local, Item, Expr, Semi, Empty, MacCall]
         );
         ast_visit::walk_stmt(self, s)
@@ -396,7 +537,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_pat(&mut self, p: &'v ast::Pat) {
         record_variants!(
-            (self, p, p.kind, Pat, PatKind),
+            (self, p, p.kind, Id::None, ast, Pat, PatKind),
             [
                 Wild,
                 Ident,
@@ -420,7 +561,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_expr(&mut self, e: &'v ast::Expr) {
         record_variants!(
-            (self, e, e.kind, Expr, ExprKind),
+            (self, e, e.kind, Id::None, ast, Expr, ExprKind),
             [
                 Box, Array, ConstBlock, Call, MethodCall, Tup, Binary, Unary, Lit, Cast, Type, Let,
                 If, While, ForLoop, Loop, Match, Closure, Block, Async, Await, TryBlock, Assign,
@@ -433,7 +574,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_ty(&mut self, t: &'v ast::Ty) {
         record_variants!(
-            (self, t, t.kind, Ty, TyKind),
+            (self, t, t.kind, Id::None, ast, Ty, TyKind),
             [
                 Slice,
                 Array,
@@ -465,27 +606,30 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_where_predicate(&mut self, p: &'v ast::WherePredicate) {
         record_variants!(
-            (self, p, p, WherePredicate, WherePredicate),
+            (self, p, p, Id::None, ast, WherePredicate, WherePredicate),
             [BoundPredicate, RegionPredicate, EqPredicate]
         );
         ast_visit::walk_where_predicate(self, p)
     }
 
-    fn visit_fn(&mut self, fk: ast_visit::FnKind<'v>, s: Span, _: NodeId) {
+    fn visit_fn(&mut self, fk: ast_visit::FnKind<'v>, _: Span, _: NodeId) {
         self.record("FnDecl", Id::None, fk.decl());
-        ast_visit::walk_fn(self, fk, s)
+        ast_visit::walk_fn(self, fk)
     }
 
     fn visit_assoc_item(&mut self, i: &'v ast::AssocItem, ctxt: ast_visit::AssocCtxt) {
         record_variants!(
-            (self, i, i.kind, AssocItem, AssocItemKind),
+            (self, i, i.kind, Id::None, ast, AssocItem, AssocItemKind),
             [Const, Fn, TyAlias, MacCall]
         );
         ast_visit::walk_assoc_item(self, i, ctxt);
     }
 
     fn visit_param_bound(&mut self, b: &'v ast::GenericBound, _ctxt: BoundKind) {
-        record_variants!((self, b, b, GenericBound, GenericBound), [Trait, Outlives]);
+        record_variants!(
+            (self, b, b, Id::None, ast, GenericBound, GenericBound),
+            [Trait, Outlives]
+        );
         ast_visit::walk_param_bound(self, b)
     }
 
@@ -504,22 +648,32 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
     // common, so we don't implement `visit_use_tree` and tolerate the missed
     // coverage in the latter case.
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v ast::PathSegment) {
+    // `PathSegment` has one inline use (in `ast::ExprKind::MethodCall`) and
+    // one non-inline use (in `ast::Path::segments`). The latter case is more
+    // common than the former case, so we implement this visitor and tolerate
+    // the double counting in the former case.
+    fn visit_path_segment(&mut self, path_segment: &'v ast::PathSegment) {
         self.record("PathSegment", Id::None, path_segment);
-        ast_visit::walk_path_segment(self, path_span, path_segment)
+        ast_visit::walk_path_segment(self, path_segment)
     }
 
     // `GenericArgs` has one inline use (in `ast::AssocConstraint::gen_args`) and one
     // non-inline use (in `ast::PathSegment::args`). The latter case is more
     // common, so we implement `visit_generic_args` and tolerate the double
     // counting in the former case.
-    fn visit_generic_args(&mut self, sp: Span, g: &'v ast::GenericArgs) {
-        record_variants!((self, g, g, GenericArgs, GenericArgs), [AngleBracketed, Parenthesized]);
-        ast_visit::walk_generic_args(self, sp, g)
+    fn visit_generic_args(&mut self, g: &'v ast::GenericArgs) {
+        record_variants!(
+            (self, g, g, Id::None, ast, GenericArgs, GenericArgs),
+            [AngleBracketed, Parenthesized]
+        );
+        ast_visit::walk_generic_args(self, g)
     }
 
     fn visit_attribute(&mut self, attr: &'v ast::Attribute) {
-        record_variants!((self, attr, attr.kind, Attribute, AttrKind), [Normal, DocComment]);
+        record_variants!(
+            (self, attr, attr.kind, Id::None, ast, Attribute, AttrKind),
+            [Normal, DocComment]
+        );
         ast_visit::walk_attribute(self, attr)
     }
 
diff --git a/compiler/rustc_passes/src/layout_test.rs b/compiler/rustc_passes/src/layout_test.rs
index fd03f657111d..46c4a702fde9 100644
--- a/compiler/rustc_passes/src/layout_test.rs
+++ b/compiler/rustc_passes/src/layout_test.rs
@@ -16,7 +16,7 @@ pub fn test_layout(tcx: TyCtxt<'_>) {
                 DefKind::TyAlias | DefKind::Enum | DefKind::Struct | DefKind::Union
             ) {
                 for attr in tcx.get_attrs(id.def_id.to_def_id(), sym::rustc_layout) {
-                    dump_layout_of(tcx, id.def_id, attr);
+                    dump_layout_of(tcx, id.def_id.def_id, attr);
                 }
             }
         }
diff --git a/compiler/rustc_passes/src/lib.rs b/compiler/rustc_passes/src/lib.rs
index 7b2f83958af8..6e621b7eb5eb 100644
--- a/compiler/rustc_passes/src/lib.rs
+++ b/compiler/rustc_passes/src/lib.rs
@@ -8,7 +8,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(try_blocks)]
diff --git a/compiler/rustc_passes/src/lib_features.rs b/compiler/rustc_passes/src/lib_features.rs
index 70b6bfd1e582..04173c792a97 100644
--- a/compiler/rustc_passes/src/lib_features.rs
+++ b/compiler/rustc_passes/src/lib_features.rs
@@ -5,6 +5,7 @@
 //! collect them instead.
 
 use rustc_ast::{Attribute, MetaItemKind};
+use rustc_attr::{rust_version_symbol, VERSION_PLACEHOLDER};
 use rustc_errors::struct_span_err;
 use rustc_hir::intravisit::Visitor;
 use rustc_middle::hir::nested_filter;
@@ -54,12 +55,9 @@ impl<'tcx> LibFeatureCollector<'tcx> {
                         }
                     }
                 }
-                const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION";
 
                 if let Some(s) = since && s.as_str() == VERSION_PLACEHOLDER {
-                    let version = option_env!("CFG_VERSION").unwrap_or("<current>");
-                    let version = version.split(' ').next().unwrap();
-                    since = Some(Symbol::intern(&version));
+                    since = Some(rust_version_symbol());
                 }
 
                 if let Some(feature) = feature {
diff --git a/compiler/rustc_passes/src/liveness.rs b/compiler/rustc_passes/src/liveness.rs
index 5b79dd3d3ef2..6a4cd79cde71 100644
--- a/compiler/rustc_passes/src/liveness.rs
+++ b/compiler/rustc_passes/src/liveness.rs
@@ -1039,9 +1039,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                 self.propagate_through_expr(&f, succ)
             }
 
-            hir::ExprKind::MethodCall(.., ref args, _) => {
+            hir::ExprKind::MethodCall(.., receiver, ref args, _) => {
                 let succ = self.check_is_ty_uninhabited(expr, succ);
-                self.propagate_through_exprs(args, succ)
+                let succ = self.propagate_through_exprs(args, succ);
+                self.propagate_through_expr(receiver, succ)
             }
 
             hir::ExprKind::Tup(ref exprs) => self.propagate_through_exprs(exprs, succ),
@@ -1573,7 +1574,7 @@ impl<'tcx> Liveness<'_, 'tcx> {
         }
     }
 
-    #[tracing::instrument(skip(self), level = "INFO")]
+    #[instrument(skip(self), level = "INFO")]
     fn report_unused(
         &self,
         hir_ids_and_spans: Vec<(HirId, Span, Span)>,
diff --git a/compiler/rustc_passes/src/naked_functions.rs b/compiler/rustc_passes/src/naked_functions.rs
index 296b6ed5d99a..607973446fc1 100644
--- a/compiler/rustc_passes/src/naked_functions.rs
+++ b/compiler/rustc_passes/src/naked_functions.rs
@@ -76,7 +76,7 @@ fn check_no_patterns(tcx: TyCtxt<'_>, params: &[hir::Param<'_>]) {
     for param in params {
         match param.pat.kind {
             hir::PatKind::Wild
-            | hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, _, None) => {}
+            | hir::PatKind::Binding(hir::BindingAnnotation::NONE, _, _, None) => {}
             _ => {
                 tcx.sess
                     .struct_span_err(
diff --git a/compiler/rustc_passes/src/reachable.rs b/compiler/rustc_passes/src/reachable.rs
index f7e3fac6b2e2..16055641aca9 100644
--- a/compiler/rustc_passes/src/reachable.rs
+++ b/compiler/rustc_passes/src/reachable.rs
@@ -12,7 +12,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::Node;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
-use rustc_middle::middle::privacy;
+use rustc_middle::middle::privacy::{self, AccessLevel};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_session::config::CrateType;
@@ -153,7 +153,7 @@ impl<'tcx> ReachableContext<'tcx> {
                 hir::ImplItemKind::Fn(..) => {
                     let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
                     let impl_did = self.tcx.hir().get_parent_item(hir_id);
-                    method_might_be_inlined(self.tcx, impl_item, impl_did)
+                    method_might_be_inlined(self.tcx, impl_item, impl_did.def_id)
                 }
                 hir::ImplItemKind::TyAlias(_) => false,
             },
@@ -305,8 +305,8 @@ fn check_item<'tcx>(
     worklist: &mut Vec<LocalDefId>,
     access_levels: &privacy::AccessLevels,
 ) {
-    if has_custom_linkage(tcx, id.def_id) {
-        worklist.push(id.def_id);
+    if has_custom_linkage(tcx, id.def_id.def_id) {
+        worklist.push(id.def_id.def_id);
     }
 
     if !matches!(tcx.def_kind(id.def_id), DefKind::Impl) {
@@ -318,8 +318,8 @@ fn check_item<'tcx>(
     if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(ref trait_ref), ref items, .. }) =
         item.kind
     {
-        if !access_levels.is_reachable(item.def_id) {
-            worklist.extend(items.iter().map(|ii_ref| ii_ref.id.def_id));
+        if !access_levels.is_reachable(item.def_id.def_id) {
+            worklist.extend(items.iter().map(|ii_ref| ii_ref.id.def_id.def_id));
 
             let Res::Def(DefKind::Trait, trait_def_id) = trait_ref.path.res else {
                 unreachable!();
@@ -373,7 +373,13 @@ fn reachable_set<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> FxHashSet<LocalDefId> {
     //         If other crates link to us, they're going to expect to be able to
     //         use the lang items, so we need to be sure to mark them as
     //         exported.
-    reachable_context.worklist.extend(access_levels.map.keys());
+    reachable_context.worklist = access_levels
+        .iter()
+        .filter_map(|(&id, effective_vis)| {
+            effective_vis.is_public_at_level(AccessLevel::ReachableFromImplTrait).then_some(id)
+        })
+        .collect::<Vec<_>>();
+
     for item in tcx.lang_items().items().iter() {
         if let Some(def_id) = *item {
             if let Some(def_id) = def_id.as_local() {
@@ -397,8 +403,8 @@ fn reachable_set<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> FxHashSet<LocalDefId> {
         }
 
         for id in crate_items.impl_items() {
-            if has_custom_linkage(tcx, id.def_id) {
-                reachable_context.worklist.push(id.def_id);
+            if has_custom_linkage(tcx, id.def_id.def_id) {
+                reachable_context.worklist.push(id.def_id.def_id);
             }
         }
     }
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index f884e04a9511..e50beb27d2a8 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -1,8 +1,10 @@
 //! A pass that annotates every item and method with its stability level,
 //! propagating default levels lexically from parent to children ast nodes.
 
+use crate::errors;
 use rustc_attr::{
-    self as attr, ConstStability, Stability, StabilityLevel, Unstable, UnstableReason,
+    self as attr, rust_version_symbol, ConstStability, Stability, StabilityLevel, Unstable,
+    UnstableReason, VERSION_PLACEHOLDER,
 };
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_errors::{struct_span_err, Applicability};
@@ -121,16 +123,12 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
 
             if kind == AnnotationKind::Prohibited || kind == AnnotationKind::DeprecationProhibited {
                 let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
-                self.tcx.struct_span_lint_hir(USELESS_DEPRECATED, hir_id, *span, |lint| {
-                    lint.build("this `#[deprecated]` annotation has no effect")
-                        .span_suggestion_short(
-                            *span,
-                            "remove the unnecessary deprecation attribute",
-                            "",
-                            rustc_errors::Applicability::MachineApplicable,
-                        )
-                        .emit();
-                });
+                self.tcx.emit_spanned_lint(
+                    USELESS_DEPRECATED,
+                    hir_id,
+                    *span,
+                    errors::DeprecatedAnnotationHasNoEffect { span: *span },
+                );
             }
 
             // `Deprecation` is just two pointers, no need to intern it
@@ -387,7 +385,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
         }
 
         self.annotate(
-            i.def_id,
+            i.def_id.def_id,
             i.span,
             fn_sig,
             kind,
@@ -406,7 +404,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
         };
 
         self.annotate(
-            ti.def_id,
+            ti.def_id.def_id,
             ti.span,
             fn_sig,
             AnnotationKind::Required,
@@ -429,7 +427,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
         };
 
         self.annotate(
-            ii.def_id,
+            ii.def_id.def_id,
             ii.span,
             fn_sig,
             kind,
@@ -487,7 +485,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
 
     fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem<'tcx>) {
         self.annotate(
-            i.def_id,
+            i.def_id.def_id,
             i.span,
             None,
             AnnotationKind::Required,
@@ -575,25 +573,25 @@ impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> {
             hir::ItemKind::Impl(hir::Impl { of_trait: None, .. })
                 | hir::ItemKind::ForeignMod { .. }
         ) {
-            self.check_missing_stability(i.def_id, i.span);
+            self.check_missing_stability(i.def_id.def_id, i.span);
         }
 
         // Ensure stable `const fn` have a const stability attribute.
-        self.check_missing_const_stability(i.def_id, i.span);
+        self.check_missing_const_stability(i.def_id.def_id, i.span);
 
         intravisit::walk_item(self, i)
     }
 
     fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem<'tcx>) {
-        self.check_missing_stability(ti.def_id, ti.span);
+        self.check_missing_stability(ti.def_id.def_id, ti.span);
         intravisit::walk_trait_item(self, ti);
     }
 
     fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem<'tcx>) {
         let impl_def_id = self.tcx.hir().get_parent_item(ii.hir_id());
         if self.tcx.impl_trait_ref(impl_def_id).is_none() {
-            self.check_missing_stability(ii.def_id, ii.span);
-            self.check_missing_const_stability(ii.def_id, ii.span);
+            self.check_missing_stability(ii.def_id.def_id, ii.span);
+            self.check_missing_const_stability(ii.def_id.def_id, ii.span);
         }
         intravisit::walk_impl_item(self, ii);
     }
@@ -612,7 +610,7 @@ impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> {
     }
 
     fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem<'tcx>) {
-        self.check_missing_stability(i.def_id, i.span);
+        self.check_missing_stability(i.def_id.def_id, i.span);
         intravisit::walk_foreign_item(self, i);
     }
     // Note that we don't need to `check_missing_stability` for default generic parameters,
@@ -718,7 +716,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
                     return;
                 }
 
-                let Some(cnum) = self.tcx.extern_mod_stmt_cnum(item.def_id) else {
+                let Some(cnum) = self.tcx.extern_mod_stmt_cnum(item.def_id.def_id) else {
                     return;
                 };
                 let def_id = cnum.as_def_id();
@@ -832,7 +830,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
                 // added, such as `core::intrinsics::transmute`
                 let parents = path.segments.iter().rev().skip(1);
                 for path_segment in parents {
-                    if let Some(def_id) = path_segment.res.as_ref().and_then(Res::opt_def_id) {
+                    if let Some(def_id) = path_segment.res.opt_def_id() {
                         // use `None` for id to prevent deprecation check
                         self.tcx.check_stability_allow_unstable(
                             def_id,
@@ -871,7 +869,7 @@ fn is_unstable_reexport<'tcx>(tcx: TyCtxt<'tcx>, id: hir::HirId) -> bool {
     }
 
     // If this is a path that isn't a use, we don't need to do anything special
-    if !matches!(tcx.hir().item(hir::ItemId { def_id }).kind, ItemKind::Use(..)) {
+    if !matches!(tcx.hir().expect_item(def_id).kind, ItemKind::Use(..)) {
         return false;
     }
 
@@ -1106,7 +1104,15 @@ fn unnecessary_partially_stable_feature_lint(
     });
 }
 
-fn unnecessary_stable_feature_lint(tcx: TyCtxt<'_>, span: Span, feature: Symbol, since: Symbol) {
+fn unnecessary_stable_feature_lint(
+    tcx: TyCtxt<'_>,
+    span: Span,
+    feature: Symbol,
+    mut since: Symbol,
+) {
+    if since.as_str() == VERSION_PLACEHOLDER {
+        since = rust_version_symbol();
+    }
     tcx.struct_span_lint_hir(lint::builtin::STABLE_FEATURES, hir::CRATE_HIR_ID, span, |lint| {
         lint.build(&format!(
             "the feature `{feature}` has been stable since {since} and no longer requires an \
diff --git a/compiler/rustc_plugin_impl/src/errors.rs b/compiler/rustc_plugin_impl/src/errors.rs
index 2bdb6e4feca9..07ce92a9b261 100644
--- a/compiler/rustc_plugin_impl/src/errors.rs
+++ b/compiler/rustc_plugin_impl/src/errors.rs
@@ -1,9 +1,9 @@
 //! Errors emitted by plugin_impl
 
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(plugin_impl::load_plugin_error)]
 pub struct LoadPluginError {
     #[primary_span]
@@ -11,7 +11,7 @@ pub struct LoadPluginError {
     pub msg: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(plugin_impl::malformed_plugin_attribute, code = "E0498")]
 pub struct MalformedPluginAttribute {
     #[primary_span]
diff --git a/compiler/rustc_privacy/src/errors.rs b/compiler/rustc_privacy/src/errors.rs
index 1e423ddb7102..f3a617c2f0fa 100644
--- a/compiler/rustc_privacy/src/errors.rs
+++ b/compiler/rustc_privacy/src/errors.rs
@@ -1,8 +1,8 @@
 use rustc_errors::DiagnosticArgFromDisplay;
-use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(privacy::field_is_private, code = "E0451")]
 pub struct FieldIsPrivate {
     #[primary_span]
@@ -14,7 +14,7 @@ pub struct FieldIsPrivate {
     pub label: FieldIsPrivateLabel,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum FieldIsPrivateLabel {
     #[label(privacy::field_is_private_is_update_syntax_label)]
     IsUpdateSyntax {
@@ -29,7 +29,7 @@ pub enum FieldIsPrivateLabel {
     },
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(privacy::item_is_private)]
 pub struct ItemIsPrivate<'a> {
     #[primary_span]
@@ -39,7 +39,7 @@ pub struct ItemIsPrivate<'a> {
     pub descr: DiagnosticArgFromDisplay<'a>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(privacy::unnamed_item_is_private)]
 pub struct UnnamedItemIsPrivate {
     #[primary_span]
@@ -48,7 +48,7 @@ pub struct UnnamedItemIsPrivate {
 }
 
 // Duplicate of `InPublicInterface` but with a different error code, shares the same slug.
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(privacy::in_public_interface, code = "E0445")]
 pub struct InPublicInterfaceTraits<'a> {
     #[primary_span]
@@ -62,7 +62,7 @@ pub struct InPublicInterfaceTraits<'a> {
 }
 
 // Duplicate of `InPublicInterfaceTraits` but with a different error code, shares the same slug.
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(privacy::in_public_interface, code = "E0446")]
 pub struct InPublicInterface<'a> {
     #[primary_span]
@@ -75,6 +75,14 @@ pub struct InPublicInterface<'a> {
     pub vis_span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(privacy::report_effective_visibility)]
+pub struct ReportEffectiveVisibility {
+    #[primary_span]
+    pub span: Span,
+    pub descr: String,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(privacy::from_private_dep_in_public_interface)]
 pub struct FromPrivateDependencyInPublicInterface<'a> {
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 5d562f18a815..41d5f54b3664 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -4,10 +4,12 @@
 #![feature(rustc_private)]
 #![feature(try_blocks)]
 #![recursion_limit = "256"]
-#![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
+#[macro_use]
+extern crate tracing;
+
 mod errors;
 
 use rustc_ast::MacroDef;
@@ -30,7 +32,7 @@ use rustc_middle::ty::{self, Const, DefIdTree, GenericParamDefKind};
 use rustc_middle::ty::{TraitRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor};
 use rustc_session::lint;
 use rustc_span::hygiene::Transparency;
-use rustc_span::symbol::{kw, Ident};
+use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Span;
 
 use std::marker::PhantomData;
@@ -39,7 +41,8 @@ use std::{cmp, fmt, mem};
 
 use errors::{
     FieldIsPrivate, FieldIsPrivateLabel, FromPrivateDependencyInPublicInterface, InPublicInterface,
-    InPublicInterfaceTraits, ItemIsPrivate, PrivateInPublicLint, UnnamedItemIsPrivate,
+    InPublicInterfaceTraits, ItemIsPrivate, PrivateInPublicLint, ReportEffectiveVisibility,
+    UnnamedItemIsPrivate,
 };
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -330,7 +333,9 @@ impl<'a, 'tcx, VL: VisibilityLike> DefIdVisitor<'tcx> for FindMin<'a, 'tcx, VL>
         _kind: &str,
         _descr: &dyn fmt::Display,
     ) -> ControlFlow<Self::BreakTy> {
-        self.min = VL::new_min(self, def_id);
+        if let Some(def_id) = def_id.as_local() {
+            self.min = VL::new_min(self, def_id);
+        }
         ControlFlow::CONTINUE
     }
 }
@@ -338,7 +343,7 @@ impl<'a, 'tcx, VL: VisibilityLike> DefIdVisitor<'tcx> for FindMin<'a, 'tcx, VL>
 trait VisibilityLike: Sized {
     const MAX: Self;
     const SHALLOW: bool = false;
-    fn new_min(find: &FindMin<'_, '_, Self>, def_id: DefId) -> Self;
+    fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self;
 
     // Returns an over-approximation (`skip_assoc_tys` = true) of visibility due to
     // associated types for which we can't determine visibility precisely.
@@ -353,8 +358,8 @@ trait VisibilityLike: Sized {
 }
 impl VisibilityLike for ty::Visibility {
     const MAX: Self = ty::Visibility::Public;
-    fn new_min(find: &FindMin<'_, '_, Self>, def_id: DefId) -> Self {
-        min(find.tcx.visibility(def_id), find.min, find.tcx)
+    fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self {
+        min(find.tcx.local_visibility(def_id), find.min, find.tcx)
     }
 }
 impl VisibilityLike for Option<AccessLevel> {
@@ -369,15 +374,8 @@ impl VisibilityLike for Option<AccessLevel> {
     // both "shallow" version of its self type and "shallow" version of its trait if it exists
     // (which require reaching the `DefId`s in them).
     const SHALLOW: bool = true;
-    fn new_min(find: &FindMin<'_, '_, Self>, def_id: DefId) -> Self {
-        cmp::min(
-            if let Some(def_id) = def_id.as_local() {
-                find.access_levels.map.get(&def_id).copied()
-            } else {
-                Self::MAX
-            },
-            find.min,
-        )
+    fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self {
+        cmp::min(find.access_levels.get_access_level(def_id), find.min)
     }
 }
 
@@ -417,7 +415,7 @@ struct ReachEverythingInTheInterfaceVisitor<'a, 'tcx> {
 
 impl<'tcx> EmbargoVisitor<'tcx> {
     fn get(&self, def_id: LocalDefId) -> Option<AccessLevel> {
-        self.access_levels.map.get(&def_id).copied()
+        self.access_levels.get_access_level(def_id)
     }
 
     fn update_with_hir_id(
@@ -434,7 +432,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         let old_level = self.get(def_id);
         // Accessibility levels can only grow.
         if level > old_level {
-            self.access_levels.map.insert(def_id, level.unwrap());
+            self.access_levels.set_access_level(def_id, level.unwrap());
             self.changed = true;
             level
         } else {
@@ -507,15 +505,15 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         let module = self.tcx.hir().get_module(module_def_id).0;
         for item_id in module.item_ids {
             let def_kind = self.tcx.def_kind(item_id.def_id);
-            let vis = self.tcx.visibility(item_id.def_id);
-            self.update_macro_reachable_def(item_id.def_id, def_kind, vis, defining_mod);
+            let vis = self.tcx.local_visibility(item_id.def_id.def_id);
+            self.update_macro_reachable_def(item_id.def_id.def_id, def_kind, vis, defining_mod);
         }
         if let Some(exports) = self.tcx.module_reexports(module_def_id) {
             for export in exports {
-                if export.vis.is_accessible_from(defining_mod.to_def_id(), self.tcx) {
+                if export.vis.is_accessible_from(defining_mod, self.tcx) {
                     if let Res::Def(def_kind, def_id) = export.res {
                         if let Some(def_id) = def_id.as_local() {
-                            let vis = self.tcx.visibility(def_id.to_def_id());
+                            let vis = self.tcx.local_visibility(def_id);
                             self.update_macro_reachable_def(def_id, def_kind, vis, defining_mod);
                         }
                     }
@@ -538,7 +536,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         match def_kind {
             // No type privacy, so can be directly marked as reachable.
             DefKind::Const | DefKind::Static(_) | DefKind::TraitAlias | DefKind::TyAlias => {
-                if vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                if vis.is_accessible_from(module, self.tcx) {
                     self.update(def_id, level);
                 }
             }
@@ -550,7 +548,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             DefKind::Macro(_) => {
                 let item = self.tcx.hir().expect_item(def_id);
                 if let hir::ItemKind::Macro(MacroDef { macro_rules: false, .. }, _) = item.kind {
-                    if vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                    if vis.is_accessible_from(module, self.tcx) {
                         self.update(def_id, level);
                     }
                 }
@@ -561,7 +559,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             // hygiene these don't need to be marked reachable. The contents of
             // the module, however may be reachable.
             DefKind::Mod => {
-                if vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                if vis.is_accessible_from(module, self.tcx) {
                     self.update_macro_reachable(def_id, module);
                 }
             }
@@ -575,8 +573,8 @@ impl<'tcx> EmbargoVisitor<'tcx> {
                     {
                         for field in struct_def.fields() {
                             let def_id = self.tcx.hir().local_def_id(field.hir_id);
-                            let field_vis = self.tcx.visibility(def_id);
-                            if field_vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                            let field_vis = self.tcx.local_visibility(def_id);
+                            if field_vis.is_accessible_from(module, self.tcx) {
                                 self.reach(def_id, level).ty();
                             }
                         }
@@ -596,6 +594,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             | DefKind::ForeignTy
             | DefKind::Fn
             | DefKind::OpaqueTy
+            | DefKind::ImplTraitPlaceholder
             | DefKind::AssocFn
             | DefKind::Trait
             | DefKind::TyParam
@@ -627,11 +626,14 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
         let item_level = match item.kind {
             hir::ItemKind::Impl { .. } => {
-                let impl_level =
-                    Option::<AccessLevel>::of_impl(item.def_id, self.tcx, &self.access_levels);
-                self.update(item.def_id, impl_level)
+                let impl_level = Option::<AccessLevel>::of_impl(
+                    item.def_id.def_id,
+                    self.tcx,
+                    &self.access_levels,
+                );
+                self.update(item.def_id.def_id, impl_level)
             }
-            _ => self.get(item.def_id),
+            _ => self.get(item.def_id.def_id),
         };
 
         // Update levels of nested things.
@@ -650,15 +652,15 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             hir::ItemKind::Impl(ref impl_) => {
                 for impl_item_ref in impl_.items {
                     if impl_.of_trait.is_some()
-                        || self.tcx.visibility(impl_item_ref.id.def_id) == ty::Visibility::Public
+                        || self.tcx.visibility(impl_item_ref.id.def_id).is_public()
                     {
-                        self.update(impl_item_ref.id.def_id, item_level);
+                        self.update(impl_item_ref.id.def_id.def_id, item_level);
                     }
                 }
             }
             hir::ItemKind::Trait(.., trait_item_refs) => {
                 for trait_item_ref in trait_item_refs {
-                    self.update(trait_item_ref.id.def_id, item_level);
+                    self.update(trait_item_ref.id.def_id.def_id, item_level);
                 }
             }
             hir::ItemKind::Struct(ref def, _) | hir::ItemKind::Union(ref def, _) => {
@@ -674,12 +676,12 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
                 }
             }
             hir::ItemKind::Macro(ref macro_def, _) => {
-                self.update_reachability_from_macro(item.def_id, macro_def);
+                self.update_reachability_from_macro(item.def_id.def_id, macro_def);
             }
             hir::ItemKind::ForeignMod { items, .. } => {
                 for foreign_item in items {
-                    if self.tcx.visibility(foreign_item.id.def_id) == ty::Visibility::Public {
-                        self.update(foreign_item.id.def_id, item_level);
+                    if self.tcx.visibility(foreign_item.id.def_id).is_public() {
+                        self.update(foreign_item.id.def_id.def_id, item_level);
                     }
                 }
             }
@@ -706,18 +708,18 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             hir::ItemKind::Use(..) => {}
             // The interface is empty.
             hir::ItemKind::GlobalAsm(..) => {}
-            hir::ItemKind::OpaqueTy(..) => {
+            hir::ItemKind::OpaqueTy(ref opaque) => {
                 // HACK(jynelson): trying to infer the type of `impl trait` breaks `async-std` (and `pub async fn` in general)
                 // Since rustdoc never needs to do codegen and doesn't care about link-time reachability,
                 // mark this as unreachable.
                 // See https://github.com/rust-lang/rust/issues/75100
-                if !self.tcx.sess.opts.actually_rustdoc {
+                if !opaque.in_trait && !self.tcx.sess.opts.actually_rustdoc {
                     // FIXME: This is some serious pessimization intended to workaround deficiencies
                     // in the reachability pass (`middle/reachable.rs`). Types are marked as link-time
                     // reachable if they are returned via `impl Trait`, even from private functions.
                     let exist_level =
                         cmp::max(item_level, Some(AccessLevel::ReachableFromImplTrait));
-                    self.reach(item.def_id, exist_level).generics().predicates().ty();
+                    self.reach(item.def_id.def_id, exist_level).generics().predicates().ty();
                 }
             }
             // Visit everything.
@@ -726,16 +728,16 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             | hir::ItemKind::Fn(..)
             | hir::ItemKind::TyAlias(..) => {
                 if item_level.is_some() {
-                    self.reach(item.def_id, item_level).generics().predicates().ty();
+                    self.reach(item.def_id.def_id, item_level).generics().predicates().ty();
                 }
             }
             hir::ItemKind::Trait(.., trait_item_refs) => {
                 if item_level.is_some() {
-                    self.reach(item.def_id, item_level).generics().predicates();
+                    self.reach(item.def_id.def_id, item_level).generics().predicates();
 
                     for trait_item_ref in trait_item_refs {
                         let tcx = self.tcx;
-                        let mut reach = self.reach(trait_item_ref.id.def_id, item_level);
+                        let mut reach = self.reach(trait_item_ref.id.def_id.def_id, item_level);
                         reach.generics().predicates();
 
                         if trait_item_ref.kind == AssocItemKind::Type
@@ -750,18 +752,22 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             }
             hir::ItemKind::TraitAlias(..) => {
                 if item_level.is_some() {
-                    self.reach(item.def_id, item_level).generics().predicates();
+                    self.reach(item.def_id.def_id, item_level).generics().predicates();
                 }
             }
             // Visit everything except for private impl items.
             hir::ItemKind::Impl(ref impl_) => {
                 if item_level.is_some() {
-                    self.reach(item.def_id, item_level).generics().predicates().ty().trait_ref();
+                    self.reach(item.def_id.def_id, item_level)
+                        .generics()
+                        .predicates()
+                        .ty()
+                        .trait_ref();
 
                     for impl_item_ref in impl_.items {
-                        let impl_item_level = self.get(impl_item_ref.id.def_id);
+                        let impl_item_level = self.get(impl_item_ref.id.def_id.def_id);
                         if impl_item_level.is_some() {
-                            self.reach(impl_item_ref.id.def_id, impl_item_level)
+                            self.reach(impl_item_ref.id.def_id.def_id, impl_item_level)
                                 .generics()
                                 .predicates()
                                 .ty();
@@ -773,7 +779,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             // Visit everything, but enum variants have their own levels.
             hir::ItemKind::Enum(ref def, _) => {
                 if item_level.is_some() {
-                    self.reach(item.def_id, item_level).generics().predicates();
+                    self.reach(item.def_id.def_id, item_level).generics().predicates();
                 }
                 for variant in def.variants {
                     let variant_level = self.get(self.tcx.hir().local_def_id(variant.id));
@@ -784,13 +790,13 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
                         }
                         // Corner case: if the variant is reachable, but its
                         // enum is not, make the enum reachable as well.
-                        self.reach(item.def_id, variant_level).ty();
+                        self.reach(item.def_id.def_id, variant_level).ty();
                     }
                     if let Some(hir_id) = variant.data.ctor_hir_id() {
                         let ctor_def_id = self.tcx.hir().local_def_id(hir_id);
                         let ctor_level = self.get(ctor_def_id);
                         if ctor_level.is_some() {
-                            self.reach(item.def_id, ctor_level).ty();
+                            self.reach(item.def_id.def_id, ctor_level).ty();
                         }
                     }
                 }
@@ -798,9 +804,9 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             // Visit everything, but foreign items have their own levels.
             hir::ItemKind::ForeignMod { items, .. } => {
                 for foreign_item in items {
-                    let foreign_item_level = self.get(foreign_item.id.def_id);
+                    let foreign_item_level = self.get(foreign_item.id.def_id.def_id);
                     if foreign_item_level.is_some() {
-                        self.reach(foreign_item.id.def_id, foreign_item_level)
+                        self.reach(foreign_item.id.def_id.def_id, foreign_item_level)
                             .generics()
                             .predicates()
                             .ty();
@@ -810,7 +816,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             // Visit everything except for private fields.
             hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
                 if item_level.is_some() {
-                    self.reach(item.def_id, item_level).generics().predicates();
+                    self.reach(item.def_id.def_id, item_level).generics().predicates();
                     for field in struct_def.fields() {
                         let def_id = self.tcx.hir().local_def_id(field.hir_id);
                         let field_level = self.get(def_id);
@@ -823,7 +829,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
                     let ctor_def_id = self.tcx.hir().local_def_id(hir_id);
                     let ctor_level = self.get(ctor_def_id);
                     if ctor_level.is_some() {
-                        self.reach(item.def_id, ctor_level).ty();
+                        self.reach(item.def_id.def_id, ctor_level).ty();
                     }
                 }
             }
@@ -904,6 +910,81 @@ impl<'tcx> DefIdVisitor<'tcx> for ReachEverythingInTheInterfaceVisitor<'_, 'tcx>
     }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Visitor, used for AccessLevels table checking
+////////////////////////////////////////////////////////////////////////////////
+pub struct TestReachabilityVisitor<'tcx, 'a> {
+    tcx: TyCtxt<'tcx>,
+    access_levels: &'a AccessLevels,
+}
+
+impl<'tcx, 'a> TestReachabilityVisitor<'tcx, 'a> {
+    fn access_level_diagnostic(&mut self, def_id: LocalDefId) {
+        let span = self.tcx.def_span(def_id.to_def_id());
+        if self.tcx.has_attr(def_id.to_def_id(), sym::rustc_effective_visibility) {
+            let mut error_msg = String::new();
+
+            let effective_vis =
+                self.access_levels.get_effective_vis(def_id).copied().unwrap_or_default();
+            for level in [
+                AccessLevel::Public,
+                AccessLevel::Exported,
+                AccessLevel::Reachable,
+                AccessLevel::ReachableFromImplTrait,
+            ] {
+                let vis_str = match effective_vis.get(level) {
+                    Some(ty::Visibility::Restricted(restricted_id)) => {
+                        format!("pub({})", self.tcx.item_name(restricted_id.to_def_id()))
+                    }
+                    Some(ty::Visibility::Public) => "pub".to_string(),
+                    None => "pub(self)".to_string(),
+                };
+                if level != AccessLevel::Public {
+                    error_msg.push_str(", ");
+                }
+                error_msg.push_str(&format!("{:?}: {}", level, vis_str));
+            }
+            self.tcx.sess.emit_err(ReportEffectiveVisibility { span, descr: error_msg });
+        }
+    }
+}
+
+impl<'tcx, 'a> Visitor<'tcx> for TestReachabilityVisitor<'tcx, 'a> {
+    fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
+        self.access_level_diagnostic(item.def_id.def_id);
+
+        match item.kind {
+            hir::ItemKind::Enum(ref def, _) => {
+                for variant in def.variants.iter() {
+                    let variant_id = self.tcx.hir().local_def_id(variant.id);
+                    self.access_level_diagnostic(variant_id);
+                    for field in variant.data.fields() {
+                        let def_id = self.tcx.hir().local_def_id(field.hir_id);
+                        self.access_level_diagnostic(def_id);
+                    }
+                }
+            }
+            hir::ItemKind::Struct(ref def, _) | hir::ItemKind::Union(ref def, _) => {
+                for field in def.fields() {
+                    let def_id = self.tcx.hir().local_def_id(field.hir_id);
+                    self.access_level_diagnostic(def_id);
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn visit_trait_item(&mut self, item: &'tcx hir::TraitItem<'tcx>) {
+        self.access_level_diagnostic(item.def_id.def_id);
+    }
+    fn visit_impl_item(&mut self, item: &'tcx hir::ImplItem<'tcx>) {
+        self.access_level_diagnostic(item.def_id.def_id);
+    }
+    fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem<'tcx>) {
+        self.access_level_diagnostic(item.def_id.def_id);
+    }
+}
+
 //////////////////////////////////////////////////////////////////////////////////////
 /// Name privacy visitor, checks privacy and reports violations.
 /// Most of name privacy checks are performed during the main resolution phase,
@@ -983,7 +1064,7 @@ impl<'tcx> Visitor<'tcx> for NamePrivacyVisitor<'tcx> {
     }
 
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
-        let orig_current_item = mem::replace(&mut self.current_item, item.def_id);
+        let orig_current_item = mem::replace(&mut self.current_item, item.def_id.def_id);
         intravisit::walk_item(self, item);
         self.current_item = orig_current_item;
     }
@@ -1059,7 +1140,7 @@ impl<'tcx> TypePrivacyVisitor<'tcx> {
     }
 
     fn item_is_accessible(&self, did: DefId) -> bool {
-        self.tcx.visibility(did).is_accessible_from(self.current_item.to_def_id(), self.tcx)
+        self.tcx.visibility(did).is_accessible_from(self.current_item, self.tcx)
     }
 
     // Take node-id of an expression or pattern and check its type for privacy.
@@ -1260,7 +1341,7 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
             }
         }
 
-        intravisit::walk_qpath(self, qpath, id, span);
+        intravisit::walk_qpath(self, qpath, id);
     }
 
     // Check types of patterns.
@@ -1286,7 +1367,7 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
 
     // Check types in item interfaces.
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
-        let orig_current_item = mem::replace(&mut self.current_item, item.def_id);
+        let orig_current_item = mem::replace(&mut self.current_item, item.def_id.def_id);
         let old_maybe_typeck_results = self.maybe_typeck_results.take();
         intravisit::walk_item(self, item);
         self.maybe_typeck_results = old_maybe_typeck_results;
@@ -1428,7 +1509,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
             hir::ItemKind::ForeignMod { .. } => {}
 
             hir::ItemKind::Trait(.., bounds, _) => {
-                if !self.trait_is_public(item.def_id) {
+                if !self.trait_is_public(item.def_id.def_id) {
                     return;
                 }
 
@@ -1489,7 +1570,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
                         let impl_item = self.tcx.hir().impl_item(impl_item_ref.id);
                         match impl_item.kind {
                             hir::ImplItemKind::Const(..) | hir::ImplItemKind::Fn(..) => {
-                                self.access_levels.is_reachable(impl_item_ref.id.def_id)
+                                self.access_levels.is_reachable(impl_item_ref.id.def_id.def_id)
                             }
                             hir::ImplItemKind::TyAlias(_) => false,
                         }
@@ -1509,7 +1590,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
                                 let impl_item = self.tcx.hir().impl_item(impl_item_ref.id);
                                 match impl_item.kind {
                                     hir::ImplItemKind::Const(..) | hir::ImplItemKind::Fn(..)
-                                        if self.item_is_public(impl_item.def_id) =>
+                                        if self.item_is_public(impl_item.def_id.def_id) =>
                                     {
                                         intravisit::walk_impl_item(self, impl_item)
                                     }
@@ -1550,9 +1631,8 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
                     // methods will be visible as `Public::foo`.
                     let mut found_pub_static = false;
                     for impl_item_ref in impl_.items {
-                        if self.access_levels.is_reachable(impl_item_ref.id.def_id)
-                            || self.tcx.visibility(impl_item_ref.id.def_id)
-                                == ty::Visibility::Public
+                        if self.access_levels.is_reachable(impl_item_ref.id.def_id.def_id)
+                            || self.tcx.visibility(impl_item_ref.id.def_id).is_public()
                         {
                             let impl_item = self.tcx.hir().impl_item(impl_item_ref.id);
                             match impl_item_ref.kind {
@@ -1580,7 +1660,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
             hir::ItemKind::TyAlias(..) => return,
 
             // Not at all public, so we don't care.
-            _ if !self.item_is_public(item.def_id) => {
+            _ if !self.item_is_public(item.def_id.def_id) => {
                 return;
             }
 
@@ -1611,7 +1691,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
     }
 
     fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem<'tcx>) {
-        if self.access_levels.is_reachable(item.def_id) {
+        if self.access_levels.is_reachable(item.def_id.def_id) {
             intravisit::walk_foreign_item(self, item)
         }
     }
@@ -1722,17 +1802,17 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
             );
         }
 
-        let hir_id = match def_id.as_local() {
-            Some(def_id) => self.tcx.hir().local_def_id_to_hir_id(def_id),
-            None => return false,
+        let Some(local_def_id) = def_id.as_local() else {
+            return false;
         };
 
-        let vis = self.tcx.visibility(def_id);
+        let vis = self.tcx.local_visibility(local_def_id);
         if !vis.is_at_least(self.required_visibility, self.tcx) {
+            let hir_id = self.tcx.hir().local_def_id_to_hir_id(local_def_id);
             let vis_descr = match vis {
                 ty::Visibility::Public => "public",
                 ty::Visibility::Restricted(vis_def_id) => {
-                    if vis_def_id == self.tcx.parent_module(hir_id).to_def_id() {
+                    if vis_def_id == self.tcx.parent_module(hir_id) {
                         "private"
                     } else if vis_def_id.is_top_level_module() {
                         "crate-private"
@@ -1784,7 +1864,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
     fn leaks_private_dep(&self, item_id: DefId) -> bool {
         let ret = self.required_visibility.is_public() && self.tcx.is_private_dep(item_id.krate);
 
-        tracing::debug!("leaks_private_dep(item_id={:?})={}", item_id, ret);
+        debug!("leaks_private_dep(item_id={:?})={}", item_id, ret);
         ret
     }
 }
@@ -1848,43 +1928,44 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
 
     pub fn check_item(&mut self, id: ItemId) {
         let tcx = self.tcx;
-        let item_visibility = tcx.visibility(id.def_id);
-        let def_kind = tcx.def_kind(id.def_id);
+        let def_id = id.def_id.def_id;
+        let item_visibility = tcx.local_visibility(def_id);
+        let def_kind = tcx.def_kind(def_id);
 
         match def_kind {
             DefKind::Const | DefKind::Static(_) | DefKind::Fn | DefKind::TyAlias => {
-                self.check(id.def_id, item_visibility).generics().predicates().ty();
+                self.check(def_id, item_visibility).generics().predicates().ty();
             }
             DefKind::OpaqueTy => {
                 // `ty()` for opaque types is the underlying type,
                 // it's not a part of interface, so we skip it.
-                self.check(id.def_id, item_visibility).generics().bounds();
+                self.check(def_id, item_visibility).generics().bounds();
             }
             DefKind::Trait => {
                 let item = tcx.hir().item(id);
                 if let hir::ItemKind::Trait(.., trait_item_refs) = item.kind {
-                    self.check(item.def_id, item_visibility).generics().predicates();
+                    self.check(item.def_id.def_id, item_visibility).generics().predicates();
 
                     for trait_item_ref in trait_item_refs {
                         self.check_assoc_item(
-                            trait_item_ref.id.def_id,
+                            trait_item_ref.id.def_id.def_id,
                             trait_item_ref.kind,
                             item_visibility,
                         );
 
                         if let AssocItemKind::Type = trait_item_ref.kind {
-                            self.check(trait_item_ref.id.def_id, item_visibility).bounds();
+                            self.check(trait_item_ref.id.def_id.def_id, item_visibility).bounds();
                         }
                     }
                 }
             }
             DefKind::TraitAlias => {
-                self.check(id.def_id, item_visibility).generics().predicates();
+                self.check(def_id, item_visibility).generics().predicates();
             }
             DefKind::Enum => {
                 let item = tcx.hir().item(id);
                 if let hir::ItemKind::Enum(ref def, _) = item.kind {
-                    self.check(item.def_id, item_visibility).generics().predicates();
+                    self.check(item.def_id.def_id, item_visibility).generics().predicates();
 
                     for variant in def.variants {
                         for field in variant.data.fields() {
@@ -1899,8 +1980,8 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
                 let item = tcx.hir().item(id);
                 if let hir::ItemKind::ForeignMod { items, .. } = item.kind {
                     for foreign_item in items {
-                        let vis = tcx.visibility(foreign_item.id.def_id);
-                        self.check(foreign_item.id.def_id, vis).generics().predicates().ty();
+                        let vis = tcx.local_visibility(foreign_item.id.def_id.def_id);
+                        self.check(foreign_item.id.def_id.def_id, vis).generics().predicates().ty();
                     }
                 }
             }
@@ -1910,11 +1991,11 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
                 if let hir::ItemKind::Struct(ref struct_def, _)
                 | hir::ItemKind::Union(ref struct_def, _) = item.kind
                 {
-                    self.check(item.def_id, item_visibility).generics().predicates();
+                    self.check(item.def_id.def_id, item_visibility).generics().predicates();
 
                     for field in struct_def.fields() {
                         let def_id = tcx.hir().local_def_id(field.hir_id);
-                        let field_visibility = tcx.visibility(def_id);
+                        let field_visibility = tcx.local_visibility(def_id);
                         self.check(def_id, min(item_visibility, field_visibility, tcx)).ty();
                     }
                 }
@@ -1926,20 +2007,21 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
             DefKind::Impl => {
                 let item = tcx.hir().item(id);
                 if let hir::ItemKind::Impl(ref impl_) = item.kind {
-                    let impl_vis = ty::Visibility::of_impl(item.def_id, tcx, &Default::default());
+                    let impl_vis =
+                        ty::Visibility::of_impl(item.def_id.def_id, tcx, &Default::default());
                     // check that private components do not appear in the generics or predicates of inherent impls
                     // this check is intentionally NOT performed for impls of traits, per #90586
                     if impl_.of_trait.is_none() {
-                        self.check(item.def_id, impl_vis).generics().predicates();
+                        self.check(item.def_id.def_id, impl_vis).generics().predicates();
                     }
                     for impl_item_ref in impl_.items {
                         let impl_item_vis = if impl_.of_trait.is_none() {
-                            min(tcx.visibility(impl_item_ref.id.def_id), impl_vis, tcx)
+                            min(tcx.local_visibility(impl_item_ref.id.def_id.def_id), impl_vis, tcx)
                         } else {
                             impl_vis
                         };
                         self.check_assoc_item(
-                            impl_item_ref.id.def_id,
+                            impl_item_ref.id.def_id.def_id,
                             impl_item_ref.kind,
                             impl_item_vis,
                         );
@@ -1961,8 +2043,11 @@ pub fn provide(providers: &mut Providers) {
     };
 }
 
-fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility {
-    let def_id = def_id.expect_local();
+fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility<DefId> {
+    local_visibility(tcx, def_id.expect_local()).to_def_id()
+}
+
+fn local_visibility(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Visibility {
     match tcx.resolutions(()).visibilities.get(&def_id) {
         Some(vis) => *vis,
         None => {
@@ -1977,13 +2062,14 @@ fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility {
                 //   Visibility on them should have no effect, but to avoid the visibility
                 //   query failing on some items, we provide it for opaque types as well.
                 | Node::Item(hir::Item {
-                    kind: hir::ItemKind::Use(_, hir::UseKind::ListStem) | hir::ItemKind::OpaqueTy(..),
+                    kind: hir::ItemKind::Use(_, hir::UseKind::ListStem)
+                        | hir::ItemKind::OpaqueTy(..),
                     ..
-                }) => ty::Visibility::Restricted(tcx.parent_module(hir_id).to_def_id()),
+                }) => ty::Visibility::Restricted(tcx.parent_module(hir_id)),
                 // Visibilities of trait impl items are inherited from their traits
                 // and are not filled in resolve.
                 Node::ImplItem(impl_item) => {
-                    match tcx.hir().get_by_def_id(tcx.hir().get_parent_item(hir_id)) {
+                    match tcx.hir().get_by_def_id(tcx.hir().get_parent_item(hir_id).def_id) {
                         Node::Item(hir::Item {
                             kind: hir::ItemKind::Impl(hir::Impl { of_trait: Some(tr), .. }),
                             ..
@@ -1992,7 +2078,7 @@ fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility {
                                 tcx.sess.delay_span_bug(tr.path.span, "trait without a def-id");
                                 ty::Visibility::Public
                             },
-                            |def_id| tcx.visibility(def_id),
+                            |def_id| tcx.visibility(def_id).expect_local(),
                         ),
                         _ => span_bug!(impl_item.span, "the parent is not a trait impl"),
                     }
@@ -2042,6 +2128,9 @@ fn privacy_access_levels(tcx: TyCtxt<'_>, (): ()) -> &AccessLevels {
         }
     }
 
+    let mut check_visitor = TestReachabilityVisitor { tcx, access_levels: &visitor.access_levels };
+    tcx.hir().visit_all_item_likes_in_crate(&mut check_visitor);
+
     tcx.arena.alloc(visitor.access_levels)
 }
 
diff --git a/compiler/rustc_query_impl/Cargo.toml b/compiler/rustc_query_impl/Cargo.toml
index c37ae4f32536..e7f12caaf33e 100644
--- a/compiler/rustc_query_impl/Cargo.toml
+++ b/compiler/rustc_query_impl/Cargo.toml
@@ -8,7 +8,6 @@ doctest = false
 
 [dependencies]
 measureme = "10.0.0"
-rustc-rayon-core = { version = "0.4.0", optional = true }
 rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
@@ -17,10 +16,12 @@ rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_query_system = { path = "../rustc_query_system" }
+rustc-rayon-core = { version = "0.4.0", optional = true }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
+thin-vec = "0.2.8"
 tracing = "0.1"
 
 [features]
diff --git a/compiler/rustc_query_impl/src/keys.rs b/compiler/rustc_query_impl/src/keys.rs
index 49175e97f417..47762440e290 100644
--- a/compiler/rustc_query_impl/src/keys.rs
+++ b/compiler/rustc_query_impl/src/keys.rs
@@ -1,6 +1,7 @@
 //! Defines the set of legal keys that can be used in queries.
 
 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
+use rustc_hir::hir_id::OwnerId;
 use rustc_middle::infer::canonical::Canonical;
 use rustc_middle::mir;
 use rustc_middle::traits;
@@ -104,6 +105,19 @@ impl Key for CrateNum {
     }
 }
 
+impl Key for OwnerId {
+    #[inline(always)]
+    fn query_crate_is_local(&self) -> bool {
+        true
+    }
+    fn default_span(&self, tcx: TyCtxt<'_>) -> Span {
+        self.to_def_id().default_span(tcx)
+    }
+    fn key_as_def_id(&self) -> Option<DefId> {
+        Some(self.to_def_id())
+    }
+}
+
 impl Key for LocalDefId {
     #[inline(always)]
     fn query_crate_is_local(&self) -> bool {
@@ -275,7 +289,7 @@ impl<'tcx> Key for (DefId, SubstsRef<'tcx>) {
     }
 }
 
-impl<'tcx> Key for (ty::Unevaluated<'tcx, ()>, ty::Unevaluated<'tcx, ()>) {
+impl<'tcx> Key for (ty::UnevaluatedConst<'tcx>, ty::UnevaluatedConst<'tcx>) {
     #[inline(always)]
     fn query_crate_is_local(&self) -> bool {
         (self.0).def.did.krate == LOCAL_CRATE
diff --git a/compiler/rustc_query_impl/src/lib.rs b/compiler/rustc_query_impl/src/lib.rs
index 8ea09880694e..8e018d3e4a4b 100644
--- a/compiler/rustc_query_impl/src/lib.rs
+++ b/compiler/rustc_query_impl/src/lib.rs
@@ -1,6 +1,8 @@
 //! Support for serializing the dep-graph and reloading it.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+// this shouldn't be necessary, but the check for `&mut _` is too naive and denies returning a function pointer that takes a mut ref
+#![feature(const_mut_refs)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(once_cell)]
@@ -17,7 +19,7 @@ extern crate rustc_middle;
 
 use rustc_data_structures::sync::AtomicU64;
 use rustc_middle::arena::Arena;
-use rustc_middle::dep_graph::{self, DepKindStruct, SerializedDepNodeIndex};
+use rustc_middle::dep_graph::{self, DepKindStruct};
 use rustc_middle::ty::query::{query_keys, query_storage, query_stored, query_values};
 use rustc_middle::ty::query::{ExternProviders, Providers, QueryEngine};
 use rustc_middle::ty::{self, TyCtxt};
@@ -34,9 +36,6 @@ pub use rustc_query_system::query::{deadlock, QueryContext};
 mod keys;
 use keys::Key;
 
-mod values;
-use self::values::Value;
-
 pub use rustc_query_system::query::QueryConfig;
 pub(crate) use rustc_query_system::query::{QueryDescription, QueryVTable};
 
diff --git a/compiler/rustc_query_impl/src/on_disk_cache.rs b/compiler/rustc_query_impl/src/on_disk_cache.rs
index 5ef95911f562..0e93f3ce1d64 100644
--- a/compiler/rustc_query_impl/src/on_disk_cache.rs
+++ b/compiler/rustc_query_impl/src/on_disk_cache.rs
@@ -798,6 +798,12 @@ impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx FxHashSet<LocalDefId>
     }
 }
 
+impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx FxHashMap<DefId, Ty<'tcx>> {
+    fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
+        RefDecodable::decode(d)
+    }
+}
+
 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>>
     for &'tcx IndexVec<mir::Promoted, mir::Body<'tcx>>
 {
diff --git a/compiler/rustc_query_impl/src/plumbing.rs b/compiler/rustc_query_impl/src/plumbing.rs
index eab627c5d4c2..2b3850bc0dfb 100644
--- a/compiler/rustc_query_impl/src/plumbing.rs
+++ b/compiler/rustc_query_impl/src/plumbing.rs
@@ -3,23 +3,30 @@
 //! manage the caches, and so forth.
 
 use crate::keys::Key;
+use crate::on_disk_cache::{CacheDecoder, CacheEncoder, EncodedDepNodeIndex};
+use crate::profiling_support::QueryKeyStringCache;
 use crate::{on_disk_cache, Queries};
-use rustc_middle::dep_graph::{self, DepKind, DepNodeIndex, SerializedDepNodeIndex};
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::sync::{AtomicU64, Lock};
+use rustc_errors::{Diagnostic, Handler};
+use rustc_middle::dep_graph::{
+    self, DepKind, DepKindStruct, DepNode, DepNodeIndex, SerializedDepNodeIndex,
+};
 use rustc_middle::ty::tls::{self, ImplicitCtxt};
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_query_system::dep_graph::HasDepContext;
+use rustc_query_system::dep_graph::{DepNodeParams, HasDepContext};
 use rustc_query_system::ich::StableHashingContext;
 use rustc_query_system::query::{
-    QueryContext, QueryJobId, QueryMap, QuerySideEffects, QueryStackFrame,
+    force_query, QueryConfig, QueryContext, QueryDescription, QueryJobId, QueryMap,
+    QuerySideEffects, QueryStackFrame,
 };
-
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_data_structures::sync::Lock;
-use rustc_data_structures::thin_vec::ThinVec;
-use rustc_errors::{Diagnostic, Handler};
-
+use rustc_query_system::{LayoutOfDepth, QueryOverflow, Value};
+use rustc_serialize::Decodable;
+use rustc_session::Limit;
+use rustc_span::def_id::LOCAL_CRATE;
 use std::any::Any;
 use std::num::NonZeroU64;
+use thin_vec::ThinVec;
 
 #[derive(Copy, Clone)]
 pub struct QueryCtxt<'tcx> {
@@ -105,7 +112,7 @@ impl QueryContext for QueryCtxt<'_> {
         // when accessing the `ImplicitCtxt`.
         tls::with_related_context(**self, move |current_icx| {
             if depth_limit && !self.recursion_limit().value_within_limit(current_icx.query_depth) {
-                self.depth_limit_error();
+                self.depth_limit_error(token);
             }
 
             // Update the `ImplicitCtxt` to point to our new query job.
@@ -123,6 +130,29 @@ impl QueryContext for QueryCtxt<'_> {
             })
         })
     }
+
+    fn depth_limit_error(&self, job: QueryJobId) {
+        let mut span = None;
+        let mut layout_of_depth = None;
+        if let Some(map) = self.try_collect_active_jobs() {
+            if let Some((info, depth)) = job.try_find_layout_root(map) {
+                span = Some(info.job.span);
+                layout_of_depth = Some(LayoutOfDepth { desc: info.query.description, depth });
+            }
+        }
+
+        let suggested_limit = match self.recursion_limit() {
+            Limit(0) => Limit(2),
+            limit => limit * 2,
+        };
+
+        self.sess.emit_fatal(QueryOverflow {
+            span,
+            layout_of_depth,
+            suggested_limit,
+            crate_name: self.crate_name(LOCAL_CRATE),
+        });
+    }
 }
 
 impl<'tcx> QueryCtxt<'tcx> {
@@ -144,22 +174,14 @@ impl<'tcx> QueryCtxt<'tcx> {
 
     pub(super) fn encode_query_results(
         self,
-        encoder: &mut on_disk_cache::CacheEncoder<'_, 'tcx>,
-        query_result_index: &mut on_disk_cache::EncodedDepNodeIndex,
+        encoder: &mut CacheEncoder<'_, 'tcx>,
+        query_result_index: &mut EncodedDepNodeIndex,
     ) {
-        macro_rules! encode_queries {
-            ($($query:ident,)*) => {
-                $(
-                    on_disk_cache::encode_query_results::<_, super::queries::$query<'_>>(
-                        self,
-                        encoder,
-                        query_result_index
-                    );
-                )*
+        for query in &self.queries.query_structs {
+            if let Some(encode) = query.encode_query_results {
+                encode(self, encoder, query_result_index);
             }
         }
-
-        rustc_cached_queries!(encode_queries!);
     }
 
     pub fn try_print_query_stack(
@@ -172,22 +194,26 @@ impl<'tcx> QueryCtxt<'tcx> {
     }
 }
 
+#[derive(Clone, Copy)]
+pub(crate) struct QueryStruct<'tcx> {
+    pub try_collect_active_jobs: fn(QueryCtxt<'tcx>, &mut QueryMap) -> Option<()>,
+    pub alloc_self_profile_query_strings: fn(TyCtxt<'tcx>, &mut QueryKeyStringCache),
+    pub encode_query_results:
+        Option<fn(QueryCtxt<'tcx>, &mut CacheEncoder<'_, 'tcx>, &mut EncodedDepNodeIndex)>,
+}
+
 macro_rules! handle_cycle_error {
-    ([][$tcx: expr, $error:expr]) => {{
-        $error.emit();
-        Value::from_cycle_error($tcx)
+    ([]) => {{
+        rustc_query_system::HandleCycleError::Error
     }};
-    ([(fatal_cycle) $($rest:tt)*][$tcx:expr, $error:expr]) => {{
-        $error.emit();
-        $tcx.sess.abort_if_errors();
-        unreachable!()
+    ([(fatal_cycle) $($rest:tt)*]) => {{
+        rustc_query_system::HandleCycleError::Fatal
     }};
-    ([(cycle_delay_bug) $($rest:tt)*][$tcx:expr, $error:expr]) => {{
-        $error.delay_as_bug();
-        Value::from_cycle_error($tcx)
+    ([(cycle_delay_bug) $($rest:tt)*]) => {{
+        rustc_query_system::HandleCycleError::DelayBug
     }};
-    ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
-        handle_cycle_error!([$($modifiers)*][$($args)*])
+    ([$other:tt $($modifiers:tt)*]) => {
+        handle_cycle_error!([$($modifiers)*])
     };
 }
 
@@ -255,6 +281,18 @@ macro_rules! get_provider {
     };
 }
 
+macro_rules! should_ever_cache_on_disk {
+    ([]) => {{
+        None
+    }};
+    ([(cache) $($rest:tt)*]) => {{
+        Some($crate::plumbing::try_load_from_disk::<Self::Value>)
+    }};
+    ([$other:tt $($modifiers:tt)*]) => {
+        should_ever_cache_on_disk!([$($modifiers)*])
+    };
+}
+
 pub(crate) fn create_query_frame<
     'tcx,
     K: Copy + Key + for<'a> HashStable<StableHashingContext<'a>>,
@@ -300,6 +338,107 @@ pub(crate) fn create_query_frame<
     QueryStackFrame::new(name, description, span, def_kind, hash)
 }
 
+fn try_load_from_on_disk_cache<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode)
+where
+    Q: QueryDescription<QueryCtxt<'tcx>>,
+    Q::Key: DepNodeParams<TyCtxt<'tcx>>,
+{
+    debug_assert!(tcx.dep_graph.is_green(&dep_node));
+
+    let key = Q::Key::recover(tcx, &dep_node).unwrap_or_else(|| {
+        panic!("Failed to recover key for {:?} with hash {}", dep_node, dep_node.hash)
+    });
+    if Q::cache_on_disk(tcx, &key) {
+        let _ = Q::execute_query(tcx, key);
+    }
+}
+
+pub(crate) fn try_load_from_disk<'tcx, V>(
+    tcx: QueryCtxt<'tcx>,
+    id: SerializedDepNodeIndex,
+) -> Option<V>
+where
+    V: for<'a> Decodable<CacheDecoder<'a, 'tcx>>,
+{
+    tcx.on_disk_cache().as_ref()?.try_load_query_result(*tcx, id)
+}
+
+fn force_from_dep_node<'tcx, Q>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> bool
+where
+    Q: QueryDescription<QueryCtxt<'tcx>>,
+    Q::Key: DepNodeParams<TyCtxt<'tcx>>,
+    Q::Value: Value<TyCtxt<'tcx>>,
+{
+    // We must avoid ever having to call `force_from_dep_node()` for a
+    // `DepNode::codegen_unit`:
+    // Since we cannot reconstruct the query key of a `DepNode::codegen_unit`, we
+    // would always end up having to evaluate the first caller of the
+    // `codegen_unit` query that *is* reconstructible. This might very well be
+    // the `compile_codegen_unit` query, thus re-codegenning the whole CGU just
+    // to re-trigger calling the `codegen_unit` query with the right key. At
+    // that point we would already have re-done all the work we are trying to
+    // avoid doing in the first place.
+    // The solution is simple: Just explicitly call the `codegen_unit` query for
+    // each CGU, right after partitioning. This way `try_mark_green` will always
+    // hit the cache instead of having to go through `force_from_dep_node`.
+    // This assertion makes sure, we actually keep applying the solution above.
+    debug_assert!(
+        dep_node.kind != DepKind::codegen_unit,
+        "calling force_from_dep_node() on DepKind::codegen_unit"
+    );
+
+    if let Some(key) = Q::Key::recover(tcx, &dep_node) {
+        #[cfg(debug_assertions)]
+        let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered();
+        let tcx = QueryCtxt::from_tcx(tcx);
+        force_query::<Q, _>(tcx, key, dep_node);
+        true
+    } else {
+        false
+    }
+}
+
+pub(crate) fn query_callback<'tcx, Q: QueryConfig>(
+    is_anon: bool,
+    is_eval_always: bool,
+) -> DepKindStruct<'tcx>
+where
+    Q: QueryDescription<QueryCtxt<'tcx>>,
+    Q::Key: DepNodeParams<TyCtxt<'tcx>>,
+{
+    let fingerprint_style = Q::Key::fingerprint_style();
+
+    if is_anon || !fingerprint_style.reconstructible() {
+        return DepKindStruct {
+            is_anon,
+            is_eval_always,
+            fingerprint_style,
+            force_from_dep_node: None,
+            try_load_from_on_disk_cache: None,
+        };
+    }
+
+    DepKindStruct {
+        is_anon,
+        is_eval_always,
+        fingerprint_style,
+        force_from_dep_node: Some(force_from_dep_node::<Q>),
+        try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache::<Q>),
+    }
+}
+
+macro_rules! expand_if_cached {
+    ([], $tokens:expr) => {{
+        None
+    }};
+    ([(cache) $($rest:tt)*], $tokens:expr) => {{
+        Some($tokens)
+    }};
+    ([$other:tt $($modifiers:tt)*], $tokens:expr) => {
+        expand_if_cached!([$($modifiers)*], $tokens)
+    };
+}
+
 // NOTE: `$V` isn't used here, but we still need to match on it so it can be passed to other macros
 // invoked by `rustc_query_append`.
 macro_rules! define_queries {
@@ -310,18 +449,6 @@ macro_rules! define_queries {
             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
         }
 
-        mod make_query {
-            use super::*;
-
-            // Create an eponymous constructor for each query.
-            $(#[allow(nonstandard_style)] $(#[$attr])*
-            pub fn $name<'tcx>(tcx: QueryCtxt<'tcx>, key: <queries::$name<'tcx> as QueryConfig>::Key) -> QueryStackFrame {
-                let kind = dep_graph::DepKind::$name;
-                let name = stringify!($name);
-                $crate::plumbing::create_query_frame(tcx, queries::$name::describe, key, kind, name)
-            })*
-        }
-
         #[allow(nonstandard_style)]
         mod queries {
             use std::marker::PhantomData;
@@ -369,24 +496,24 @@ macro_rules! define_queries {
                     depth_limit: depth_limit!([$($modifiers)*]),
                     dep_kind: dep_graph::DepKind::$name,
                     hash_result: hash_result!([$($modifiers)*]),
-                    handle_cycle_error: |tcx, mut error| handle_cycle_error!([$($modifiers)*][tcx, error]),
+                    handle_cycle_error: handle_cycle_error!([$($modifiers)*]),
                     compute,
-                    cache_on_disk,
-                    try_load_from_disk: Self::TRY_LOAD_FROM_DISK,
+                    try_load_from_disk: if cache_on_disk { should_ever_cache_on_disk!([$($modifiers)*]) } else { None },
                 }
             }
+
+            fn execute_query(tcx: TyCtxt<'tcx>, k: Self::Key) -> Self::Stored {
+                tcx.$name(k)
+            }
         })*
 
         #[allow(nonstandard_style)]
         mod query_callbacks {
             use super::*;
-            use rustc_middle::dep_graph::DepNode;
-            use rustc_query_system::dep_graph::DepNodeParams;
-            use rustc_query_system::query::{force_query, QueryDescription};
             use rustc_query_system::dep_graph::FingerprintStyle;
 
             // We use this for most things when incr. comp. is turned off.
-            pub fn Null() -> DepKindStruct {
+            pub fn Null<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -397,7 +524,7 @@ macro_rules! define_queries {
             }
 
             // We use this for the forever-red node.
-            pub fn Red() -> DepKindStruct {
+            pub fn Red<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -407,7 +534,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub fn TraitSelect() -> DepKindStruct {
+            pub fn TraitSelect<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: true,
                     is_eval_always: false,
@@ -417,7 +544,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub fn CompileCodegenUnit() -> DepKindStruct {
+            pub fn CompileCodegenUnit<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -427,7 +554,7 @@ macro_rules! define_queries {
                 }
             }
 
-            pub fn CompileMonoItem() -> DepKindStruct {
+            pub fn CompileMonoItem<'tcx>() -> DepKindStruct<'tcx> {
                 DepKindStruct {
                     is_anon: false,
                     is_eval_always: false,
@@ -437,71 +564,101 @@ macro_rules! define_queries {
                 }
             }
 
-            $(pub(crate) fn $name()-> DepKindStruct {
-                let is_anon = is_anon!([$($modifiers)*]);
-                let is_eval_always = is_eval_always!([$($modifiers)*]);
-
-                let fingerprint_style =
-                    <<queries::$name<'_> as QueryConfig>::Key as DepNodeParams<TyCtxt<'_>>>::fingerprint_style();
-
-                if is_anon || !fingerprint_style.reconstructible() {
-                    return DepKindStruct {
-                        is_anon,
-                        is_eval_always,
-                        fingerprint_style,
-                        force_from_dep_node: None,
-                        try_load_from_on_disk_cache: None,
-                    }
-                }
-
-                #[inline(always)]
-                fn recover<'tcx>(tcx: TyCtxt<'tcx>, dep_node: DepNode) -> Option<<queries::$name<'tcx> as QueryConfig>::Key> {
-                    <<queries::$name<'_> as QueryConfig>::Key as DepNodeParams<TyCtxt<'_>>>::recover(tcx, &dep_node)
-                }
-
-                fn force_from_dep_node(tcx: TyCtxt<'_>, dep_node: DepNode) -> bool {
-                    if let Some(key) = recover(tcx, dep_node) {
-                        #[cfg(debug_assertions)]
-                        let _guard = tracing::span!(tracing::Level::TRACE, stringify!($name), ?key).entered();
-                        let tcx = QueryCtxt::from_tcx(tcx);
-                        force_query::<queries::$name<'_>, _>(tcx, key, dep_node);
-                        true
-                    } else {
-                        false
-                    }
-                }
-
-                fn try_load_from_on_disk_cache(tcx: TyCtxt<'_>, dep_node: DepNode) {
-                    debug_assert!(tcx.dep_graph.is_green(&dep_node));
-
-                    let key = recover(tcx, dep_node).unwrap_or_else(|| panic!("Failed to recover key for {:?} with hash {}", dep_node, dep_node.hash));
-                    if queries::$name::cache_on_disk(tcx, &key) {
-                        let _ = tcx.$name(key);
-                    }
-                }
-
-                DepKindStruct {
-                    is_anon,
-                    is_eval_always,
-                    fingerprint_style,
-                    force_from_dep_node: Some(force_from_dep_node),
-                    try_load_from_on_disk_cache: Some(try_load_from_on_disk_cache),
-                }
+            $(pub(crate) fn $name<'tcx>()-> DepKindStruct<'tcx> {
+                $crate::plumbing::query_callback::<queries::$name<'tcx>>(
+                    is_anon!([$($modifiers)*]),
+                    is_eval_always!([$($modifiers)*]),
+                )
             })*
         }
 
-        pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct] {
+        mod query_structs {
+            use rustc_middle::ty::TyCtxt;
+            use $crate::plumbing::{QueryStruct, QueryCtxt};
+            use $crate::profiling_support::QueryKeyStringCache;
+            use rustc_query_system::query::{QueryDescription, QueryMap};
+
+            pub(super) const fn dummy_query_struct<'tcx>() -> QueryStruct<'tcx> {
+                fn noop_try_collect_active_jobs(_: QueryCtxt<'_>, _: &mut QueryMap) -> Option<()> {
+                    None
+                }
+                fn noop_alloc_self_profile_query_strings(_: TyCtxt<'_>, _: &mut QueryKeyStringCache) {}
+
+                QueryStruct {
+                    try_collect_active_jobs: noop_try_collect_active_jobs,
+                    alloc_self_profile_query_strings: noop_alloc_self_profile_query_strings,
+                    encode_query_results: None,
+                }
+            }
+
+            pub(super) use dummy_query_struct as Null;
+            pub(super) use dummy_query_struct as Red;
+            pub(super) use dummy_query_struct as TraitSelect;
+            pub(super) use dummy_query_struct as CompileCodegenUnit;
+            pub(super) use dummy_query_struct as CompileMonoItem;
+
+            $(
+            pub(super) const fn $name<'tcx>() -> QueryStruct<'tcx> { QueryStruct {
+                try_collect_active_jobs: |tcx, qmap| {
+                    let make_query = |tcx, key| {
+                        let kind = rustc_middle::dep_graph::DepKind::$name;
+                        let name = stringify!($name);
+                        $crate::plumbing::create_query_frame(tcx, super::queries::$name::describe, key, kind, name)
+                    };
+                    tcx.queries.$name.try_collect_active_jobs(
+                        tcx,
+                        make_query,
+                        qmap,
+                    )
+                },
+                alloc_self_profile_query_strings: |tcx, string_cache| {
+                    $crate::profiling_support::alloc_self_profile_query_strings_for_query_cache(
+                        tcx,
+                        stringify!($name),
+                        &tcx.query_caches.$name,
+                        string_cache,
+                    )
+                },
+                encode_query_results: expand_if_cached!([$($modifiers)*], |tcx, encoder, query_result_index|
+                    $crate::on_disk_cache::encode_query_results::<_, super::queries::$name<'_>>(tcx, encoder, query_result_index)
+                ),
+            }})*
+        }
+
+        pub fn query_callbacks<'tcx>(arena: &'tcx Arena<'tcx>) -> &'tcx [DepKindStruct<'tcx>] {
             arena.alloc_from_iter(make_dep_kind_array!(query_callbacks))
         }
     }
 }
 
+use crate::{ExternProviders, OnDiskCache, Providers};
+
+impl<'tcx> Queries<'tcx> {
+    pub fn new(
+        local_providers: Providers,
+        extern_providers: ExternProviders,
+        on_disk_cache: Option<OnDiskCache<'tcx>>,
+    ) -> Self {
+        use crate::query_structs;
+        Queries {
+            local_providers: Box::new(local_providers),
+            extern_providers: Box::new(extern_providers),
+            query_structs: make_dep_kind_array!(query_structs).to_vec(),
+            on_disk_cache,
+            jobs: AtomicU64::new(1),
+            ..Queries::default()
+        }
+    }
+}
+
 macro_rules! define_queries_struct {
     (
      input: ($(([$($modifiers:tt)*] [$($attr:tt)*] [$name:ident]))*)) => {
+        #[derive(Default)]
         pub struct Queries<'tcx> {
             local_providers: Box<Providers>,
             extern_providers: Box<ExternProviders>,
+            query_structs: Vec<$crate::plumbing::QueryStruct<'tcx>>,
 
             pub on_disk_cache: Option<OnDiskCache<'tcx>>,
 
@@ -511,20 +668,6 @@ macro_rules! define_queries_struct {
         }
 
         impl<'tcx> Queries<'tcx> {
-            pub fn new(
-                local_providers: Providers,
-                extern_providers: ExternProviders,
-                on_disk_cache: Option<OnDiskCache<'tcx>>,
-            ) -> Self {
-                Queries {
-                    local_providers: Box::new(local_providers),
-                    extern_providers: Box::new(extern_providers),
-                    on_disk_cache,
-                    jobs: AtomicU64::new(1),
-                    $($name: Default::default()),*
-                }
-            }
-
             pub(crate) fn try_collect_active_jobs(
                 &'tcx self,
                 tcx: TyCtxt<'tcx>,
@@ -532,13 +675,9 @@ macro_rules! define_queries_struct {
                 let tcx = QueryCtxt { tcx, queries: self };
                 let mut jobs = QueryMap::default();
 
-                $(
-                    self.$name.try_collect_active_jobs(
-                        tcx,
-                        make_query::$name,
-                        &mut jobs,
-                    )?;
-                )*
+                for query in &self.query_structs {
+                    (query.try_collect_active_jobs)(tcx, &mut jobs);
+                }
 
                 Some(jobs)
             }
@@ -557,7 +696,7 @@ macro_rules! define_queries_struct {
 
             $($(#[$attr])*
             #[inline(always)]
-            #[tracing::instrument(level = "trace", skip(self, tcx))]
+            #[tracing::instrument(level = "trace", skip(self, tcx), ret)]
             fn $name(
                 &'tcx self,
                 tcx: TyCtxt<'tcx>,
diff --git a/compiler/rustc_query_impl/src/profiling_support.rs b/compiler/rustc_query_impl/src/profiling_support.rs
index 260af0d54081..2cc311d48c8f 100644
--- a/compiler/rustc_query_impl/src/profiling_support.rs
+++ b/compiler/rustc_query_impl/src/profiling_support.rs
@@ -1,3 +1,4 @@
+use crate::QueryCtxt;
 use measureme::{StringComponent, StringId};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::profiling::SelfProfiler;
@@ -8,7 +9,7 @@ use rustc_query_system::query::QueryCache;
 use std::fmt::Debug;
 use std::io::Write;
 
-struct QueryKeyStringCache {
+pub(crate) struct QueryKeyStringCache {
     def_id_cache: FxHashMap<DefId, StringId>,
 }
 
@@ -226,7 +227,7 @@ where
 /// Allocate the self-profiling query strings for a single query cache. This
 /// method is called from `alloc_self_profile_query_strings` which knows all
 /// the queries via macro magic.
-fn alloc_self_profile_query_strings_for_query_cache<'tcx, C>(
+pub(crate) fn alloc_self_profile_query_strings_for_query_cache<'tcx, C>(
     tcx: TyCtxt<'tcx>,
     query_name: &'static str,
     query_cache: &C,
@@ -298,27 +299,15 @@ fn alloc_self_profile_query_strings_for_query_cache<'tcx, C>(
 /// If we are recording only summary data, the ids will point to
 /// just the query names. If we are recording query keys too, we
 /// allocate the corresponding strings here.
-pub fn alloc_self_profile_query_strings(tcx: TyCtxt<'_>) {
+pub fn alloc_self_profile_query_strings<'tcx>(tcx: TyCtxt<'tcx>) {
     if !tcx.prof.enabled() {
         return;
     }
 
     let mut string_cache = QueryKeyStringCache::new();
+    let queries = QueryCtxt::from_tcx(tcx);
 
-    macro_rules! alloc_once {
-        (
-            $($(#[$attr:meta])* [$($modifiers:tt)*] fn $name:ident($K:ty) -> $V:ty,)*
-        ) => {
-            $({
-                alloc_self_profile_query_strings_for_query_cache(
-                    tcx,
-                    stringify!($name),
-                    &tcx.query_caches.$name,
-                    &mut string_cache,
-                );
-            })*
-        }
+    for query in &queries.queries.query_structs {
+        (query.alloc_self_profile_query_strings)(tcx, &mut string_cache);
     }
-
-    rustc_query_append! { alloc_once! }
 }
diff --git a/compiler/rustc_query_system/Cargo.toml b/compiler/rustc_query_system/Cargo.toml
index b7787aeb8f76..d7599a56c0b6 100644
--- a/compiler/rustc_query_system/Cargo.toml
+++ b/compiler/rustc_query_system/Cargo.toml
@@ -7,9 +7,8 @@ edition = "2021"
 doctest = false
 
 [dependencies]
+parking_lot = "0.11"
 rustc_arena = { path = "../rustc_arena" }
-tracing = "0.1"
-rustc-rayon-core = { version = "0.4.0", optional = true }
 rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
@@ -17,12 +16,15 @@ rustc_feature = { path = "../rustc_feature" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
+rustc-rayon-core = { version = "0.4.0", optional = true }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
-parking_lot = "0.11"
+rustc_type_ir = { path = "../rustc_type_ir" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+thin-vec = "0.2.8"
+tracing = "0.1"
 
 [features]
 rustc_use_parallel_compiler = ["rustc-rayon-core"]
diff --git a/compiler/rustc_query_system/src/dep_graph/dep_node.rs b/compiler/rustc_query_system/src/dep_graph/dep_node.rs
index 162c274d8a29..5c6ce0556eb8 100644
--- a/compiler/rustc_query_system/src/dep_graph/dep_node.rs
+++ b/compiler/rustc_query_system/src/dep_graph/dep_node.rs
@@ -47,6 +47,7 @@ use crate::ich::StableHashingContext;
 
 use rustc_data_structures::fingerprint::{Fingerprint, PackedFingerprint};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_hir::definitions::DefPathHash;
 use std::fmt;
 use std::hash::Hash;
 
@@ -88,6 +89,17 @@ impl<K: DepKind> DepNode<K> {
 
         dep_node
     }
+
+    /// Construct a DepNode from the given DepKind and DefPathHash. This
+    /// method will assert that the given DepKind actually requires a
+    /// single DefId/DefPathHash parameter.
+    pub fn from_def_path_hash<Ctxt>(tcx: Ctxt, def_path_hash: DefPathHash, kind: K) -> Self
+    where
+        Ctxt: super::DepContext<DepKind = K>,
+    {
+        debug_assert!(tcx.fingerprint_style(kind) == FingerprintStyle::DefPathHash);
+        DepNode { kind, hash: def_path_hash.0.into() }
+    }
 }
 
 impl<K: DepKind> fmt::Debug for DepNode<K> {
@@ -149,6 +161,67 @@ where
     }
 }
 
+/// This struct stores metadata about each DepKind.
+///
+/// Information is retrieved by indexing the `DEP_KINDS` array using the integer value
+/// of the `DepKind`. Overall, this allows to implement `DepContext` using this manual
+/// jump table instead of large matches.
+pub struct DepKindStruct<CTX: DepContext> {
+    /// Anonymous queries cannot be replayed from one compiler invocation to the next.
+    /// When their result is needed, it is recomputed. They are useful for fine-grained
+    /// dependency tracking, and caching within one compiler invocation.
+    pub is_anon: bool,
+
+    /// Eval-always queries do not track their dependencies, and are always recomputed, even if
+    /// their inputs have not changed since the last compiler invocation. The result is still
+    /// cached within one compiler invocation.
+    pub is_eval_always: bool,
+
+    /// Whether the query key can be recovered from the hashed fingerprint.
+    /// See [DepNodeParams] trait for the behaviour of each key type.
+    pub fingerprint_style: FingerprintStyle,
+
+    /// The red/green evaluation system will try to mark a specific DepNode in the
+    /// dependency graph as green by recursively trying to mark the dependencies of
+    /// that `DepNode` as green. While doing so, it will sometimes encounter a `DepNode`
+    /// where we don't know if it is red or green and we therefore actually have
+    /// to recompute its value in order to find out. Since the only piece of
+    /// information that we have at that point is the `DepNode` we are trying to
+    /// re-evaluate, we need some way to re-run a query from just that. This is what
+    /// `force_from_dep_node()` implements.
+    ///
+    /// In the general case, a `DepNode` consists of a `DepKind` and an opaque
+    /// GUID/fingerprint that will uniquely identify the node. This GUID/fingerprint
+    /// is usually constructed by computing a stable hash of the query-key that the
+    /// `DepNode` corresponds to. Consequently, it is not in general possible to go
+    /// back from hash to query-key (since hash functions are not reversible). For
+    /// this reason `force_from_dep_node()` is expected to fail from time to time
+    /// because we just cannot find out, from the `DepNode` alone, what the
+    /// corresponding query-key is and therefore cannot re-run the query.
+    ///
+    /// The system deals with this case letting `try_mark_green` fail which forces
+    /// the root query to be re-evaluated.
+    ///
+    /// Now, if `force_from_dep_node()` would always fail, it would be pretty useless.
+    /// Fortunately, we can use some contextual information that will allow us to
+    /// reconstruct query-keys for certain kinds of `DepNode`s. In particular, we
+    /// enforce by construction that the GUID/fingerprint of certain `DepNode`s is a
+    /// valid `DefPathHash`. Since we also always build a huge table that maps every
+    /// `DefPathHash` in the current codebase to the corresponding `DefId`, we have
+    /// everything we need to re-run the query.
+    ///
+    /// Take the `mir_promoted` query as an example. Like many other queries, it
+    /// just has a single parameter: the `DefId` of the item it will compute the
+    /// validated MIR for. Now, when we call `force_from_dep_node()` on a `DepNode`
+    /// with kind `MirValidated`, we know that the GUID/fingerprint of the `DepNode`
+    /// is actually a `DefPathHash`, and can therefore just look up the corresponding
+    /// `DefId` in `tcx.def_path_hash_to_def_id`.
+    pub force_from_dep_node: Option<fn(tcx: CTX, dep_node: DepNode<CTX::DepKind>) -> bool>,
+
+    /// Invoke a query to put the on-disk cached value in memory.
+    pub try_load_from_on_disk_cache: Option<fn(CTX, DepNode<CTX::DepKind>)>,
+}
+
 /// A "work product" corresponds to a `.o` (or other) file that we
 /// save in between runs. These IDs do not have a `DefId` but rather
 /// some independent path or string that persists between runs without
diff --git a/compiler/rustc_query_system/src/dep_graph/mod.rs b/compiler/rustc_query_system/src/dep_graph/mod.rs
index 342d95ca490e..5003a14b9108 100644
--- a/compiler/rustc_query_system/src/dep_graph/mod.rs
+++ b/compiler/rustc_query_system/src/dep_graph/mod.rs
@@ -4,7 +4,7 @@ mod graph;
 mod query;
 mod serialized;
 
-pub use dep_node::{DepNode, DepNodeParams, WorkProductId};
+pub use dep_node::{DepKindStruct, DepNode, DepNodeParams, WorkProductId};
 pub use graph::{
     hash_result, DepGraph, DepNodeColor, DepNodeIndex, TaskDeps, TaskDepsRef, WorkProduct,
 };
@@ -34,16 +34,43 @@ pub trait DepContext: Copy {
     /// Access the compiler session.
     fn sess(&self) -> &Session;
 
-    /// Return whether this kind always require evaluation.
-    fn is_eval_always(&self, kind: Self::DepKind) -> bool;
+    fn dep_kind_info(&self, dep_node: Self::DepKind) -> &DepKindStruct<Self>;
 
-    fn fingerprint_style(&self, kind: Self::DepKind) -> FingerprintStyle;
+    #[inline(always)]
+    fn fingerprint_style(&self, kind: Self::DepKind) -> FingerprintStyle {
+        let data = self.dep_kind_info(kind);
+        if data.is_anon {
+            return FingerprintStyle::Opaque;
+        }
+        data.fingerprint_style
+    }
+
+    #[inline(always)]
+    /// Return whether this kind always require evaluation.
+    fn is_eval_always(&self, kind: Self::DepKind) -> bool {
+        self.dep_kind_info(kind).is_eval_always
+    }
 
     /// Try to force a dep node to execute and see if it's green.
-    fn try_force_from_dep_node(&self, dep_node: DepNode<Self::DepKind>) -> bool;
+    fn try_force_from_dep_node(self, dep_node: DepNode<Self::DepKind>) -> bool {
+        debug!("try_force_from_dep_node({:?}) --- trying to force", dep_node);
+
+        let cb = self.dep_kind_info(dep_node.kind);
+        if let Some(f) = cb.force_from_dep_node {
+            f(self, dep_node);
+            true
+        } else {
+            false
+        }
+    }
 
     /// Load data from the on-disk cache.
-    fn try_load_from_on_disk_cache(&self, dep_node: DepNode<Self::DepKind>);
+    fn try_load_from_on_disk_cache(self, dep_node: DepNode<Self::DepKind>) {
+        let cb = self.dep_kind_info(dep_node.kind);
+        if let Some(f) = cb.try_load_from_on_disk_cache {
+            f(self, dep_node)
+        }
+    }
 }
 
 pub trait HasDepContext: Copy {
diff --git a/compiler/rustc_query_system/src/error.rs b/compiler/rustc_query_system/src/error.rs
new file mode 100644
index 000000000000..8602a4cf5aef
--- /dev/null
+++ b/compiler/rustc_query_system/src/error.rs
@@ -0,0 +1,97 @@
+use rustc_errors::AddToDiagnostic;
+use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_session::Limit;
+use rustc_span::{Span, Symbol};
+
+pub struct CycleStack {
+    pub span: Span,
+    pub desc: String,
+}
+
+impl AddToDiagnostic for CycleStack {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        diag.span_note(self.span, &format!("...which requires {}...", self.desc));
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum HandleCycleError {
+    Error,
+    Fatal,
+    DelayBug,
+}
+
+#[derive(Subdiagnostic)]
+pub enum StackCount {
+    #[note(query_system::cycle_stack_single)]
+    Single,
+    #[note(query_system::cycle_stack_multiple)]
+    Multiple,
+}
+
+#[derive(Subdiagnostic)]
+pub enum Alias {
+    #[note(query_system::cycle_recursive_ty_alias)]
+    #[help(query_system::cycle_recursive_ty_alias_help1)]
+    #[help(query_system::cycle_recursive_ty_alias_help2)]
+    Ty,
+    #[note(query_system::cycle_recursive_trait_alias)]
+    Trait,
+}
+
+#[derive(Subdiagnostic)]
+#[note(query_system::cycle_usage)]
+pub struct CycleUsage {
+    #[primary_span]
+    pub span: Span,
+    pub usage: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(query_system::cycle, code = "E0391")]
+pub struct Cycle {
+    #[primary_span]
+    pub span: Span,
+    pub stack_bottom: String,
+    #[subdiagnostic]
+    pub cycle_stack: Vec<CycleStack>,
+    #[subdiagnostic]
+    pub stack_count: StackCount,
+    #[subdiagnostic]
+    pub alias: Option<Alias>,
+    #[subdiagnostic]
+    pub cycle_usage: Option<CycleUsage>,
+}
+
+#[derive(Diagnostic)]
+#[diag(query_system::reentrant)]
+pub struct Reentrant;
+
+#[derive(Diagnostic)]
+#[diag(query_system::increment_compilation)]
+#[help]
+#[note(query_system::increment_compilation_note1)]
+#[note(query_system::increment_compilation_note2)]
+pub struct IncrementCompilation {
+    pub run_cmd: String,
+    pub dep_node: String,
+}
+
+#[derive(Diagnostic)]
+#[help]
+#[diag(query_system::query_overflow)]
+pub struct QueryOverflow {
+    #[primary_span]
+    pub span: Option<Span>,
+    #[subdiagnostic]
+    pub layout_of_depth: Option<LayoutOfDepth>,
+    pub suggested_limit: Limit,
+    pub crate_name: Symbol,
+}
+
+#[derive(Subdiagnostic)]
+#[note(query_system::layout_of_depth)]
+pub struct LayoutOfDepth {
+    pub desc: String,
+    pub depth: usize,
+}
diff --git a/compiler/rustc_query_system/src/ich/hcx.rs b/compiler/rustc_query_system/src/ich/hcx.rs
index a09b8ca30e13..8140c243453b 100644
--- a/compiler/rustc_query_system/src/ich/hcx.rs
+++ b/compiler/rustc_query_system/src/ich/hcx.rs
@@ -41,7 +41,10 @@ pub struct StableHashingContext<'a> {
 pub(super) enum BodyResolver<'tcx> {
     Forbidden,
     Ignore,
-    Traverse { owner: LocalDefId, bodies: &'tcx SortedMap<hir::ItemLocalId, &'tcx hir::Body<'tcx>> },
+    Traverse {
+        owner: hir::OwnerId,
+        bodies: &'tcx SortedMap<hir::ItemLocalId, &'tcx hir::Body<'tcx>>,
+    },
 }
 
 impl<'a> StableHashingContext<'a> {
@@ -103,7 +106,7 @@ impl<'a> StableHashingContext<'a> {
     #[inline]
     pub fn with_hir_bodies(
         &mut self,
-        owner: LocalDefId,
+        owner: hir::OwnerId,
         bodies: &SortedMap<hir::ItemLocalId, &hir::Body<'_>>,
         f: impl FnOnce(&mut StableHashingContext<'_>),
     ) {
diff --git a/compiler/rustc_query_system/src/ich/impls_syntax.rs b/compiler/rustc_query_system/src/ich/impls_syntax.rs
index d7732cb1825b..0bc811eb0441 100644
--- a/compiler/rustc_query_system/src/ich/impls_syntax.rs
+++ b/compiler/rustc_query_system/src/ich/impls_syntax.rs
@@ -148,3 +148,5 @@ impl<'tcx> HashStable<StableHashingContext<'tcx>> for rustc_feature::Features {
         });
     }
 }
+
+impl<'ctx> rustc_type_ir::HashStableContext for StableHashingContext<'ctx> {}
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index 68284dcaa0be..8f6da73d1f2d 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -1,10 +1,11 @@
 #![feature(assert_matches)]
 #![feature(core_intrinsics)]
 #![feature(hash_raw_entry)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(extern_types)]
 #![allow(rustc::potential_query_instability)]
+// #![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 #[macro_use]
 extern crate tracing;
@@ -15,5 +16,12 @@ extern crate rustc_macros;
 
 pub mod cache;
 pub mod dep_graph;
+mod error;
 pub mod ich;
 pub mod query;
+mod values;
+
+pub use error::HandleCycleError;
+pub use error::LayoutOfDepth;
+pub use error::QueryOverflow;
+pub use values::Value;
diff --git a/compiler/rustc_query_system/src/query/config.rs b/compiler/rustc_query_system/src/query/config.rs
index bd0fd7ac3503..c4549cc9eb41 100644
--- a/compiler/rustc_query_system/src/query/config.rs
+++ b/compiler/rustc_query_system/src/query/config.rs
@@ -2,12 +2,12 @@
 
 use crate::dep_graph::DepNode;
 use crate::dep_graph::SerializedDepNodeIndex;
+use crate::error::HandleCycleError;
 use crate::ich::StableHashingContext;
 use crate::query::caches::QueryCache;
 use crate::query::{QueryContext, QueryState};
 
 use rustc_data_structures::fingerprint::Fingerprint;
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
 use std::fmt::Debug;
 use std::hash::Hash;
 
@@ -19,16 +19,17 @@ pub trait QueryConfig {
     type Stored: Clone;
 }
 
+#[derive(Copy, Clone)]
 pub struct QueryVTable<CTX: QueryContext, K, V> {
     pub anon: bool,
     pub dep_kind: CTX::DepKind,
     pub eval_always: bool,
     pub depth_limit: bool,
-    pub cache_on_disk: bool,
 
     pub compute: fn(CTX::DepContext, K) -> V,
     pub hash_result: Option<fn(&mut StableHashingContext<'_>, &V) -> Fingerprint>,
-    pub handle_cycle_error: fn(CTX, DiagnosticBuilder<'_, ErrorGuaranteed>) -> V,
+    pub handle_cycle_error: HandleCycleError,
+    // NOTE: this is also `None` if `cache_on_disk()` returns false, not just if it's unsupported by the query
     pub try_load_from_disk: Option<fn(CTX, SerializedDepNodeIndex) -> Option<V>>,
 }
 
@@ -43,18 +44,9 @@ impl<CTX: QueryContext, K, V> QueryVTable<CTX, K, V> {
     pub(crate) fn compute(&self, tcx: CTX::DepContext, key: K) -> V {
         (self.compute)(tcx, key)
     }
-
-    pub(crate) fn try_load_from_disk(&self, tcx: CTX, index: SerializedDepNodeIndex) -> Option<V> {
-        self.try_load_from_disk
-            .expect("QueryDescription::load_from_disk() called for an unsupported query.")(
-            tcx, index,
-        )
-    }
 }
 
 pub trait QueryDescription<CTX: QueryContext>: QueryConfig {
-    const TRY_LOAD_FROM_DISK: Option<fn(CTX, SerializedDepNodeIndex) -> Option<Self::Value>>;
-
     type Cache: QueryCache<Key = Self::Key, Stored = Self::Stored, Value = Self::Value>;
 
     fn describe(tcx: CTX, key: Self::Key) -> String;
@@ -73,4 +65,7 @@ pub trait QueryDescription<CTX: QueryContext>: QueryConfig {
     fn make_vtable(tcx: CTX, key: &Self::Key) -> QueryVTable<CTX, Self::Key, Self::Value>;
 
     fn cache_on_disk(tcx: CTX::DepContext, key: &Self::Key) -> bool;
+
+    // Don't use this method to compute query results, instead use the methods on TyCtxt
+    fn execute_query(tcx: CTX::DepContext, k: Self::Key) -> Self::Stored;
 }
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 6d2aff38172f..64aba4703ca3 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -1,11 +1,12 @@
+use crate::error::CycleStack;
 use crate::query::plumbing::CycleError;
 use crate::query::{QueryContext, QueryStackFrame};
-use rustc_hir::def::DefKind;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{
-    struct_span_err, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, Handler, Level,
+    Diagnostic, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, Level,
 };
+use rustc_hir::def::DefKind;
 use rustc_session::Session;
 use rustc_span::Span;
 
@@ -60,6 +61,7 @@ impl QueryJobId {
     }
 }
 
+#[derive(Clone)]
 pub struct QueryJobInfo {
     pub query: QueryStackFrame,
     pub job: QueryJob,
@@ -117,10 +119,10 @@ impl QueryJob {
     }
 }
 
-#[cfg(not(parallel_compiler))]
 impl QueryJobId {
     #[cold]
     #[inline(never)]
+    #[cfg(not(parallel_compiler))]
     pub(super) fn find_cycle_in_stack(
         &self,
         query_map: QueryMap,
@@ -157,6 +159,24 @@ impl QueryJobId {
 
         panic!("did not find a cycle")
     }
+
+    #[cold]
+    #[inline(never)]
+    pub fn try_find_layout_root(&self, query_map: QueryMap) -> Option<(QueryJobInfo, usize)> {
+        let mut last_layout = None;
+        let mut current_id = Some(*self);
+        let mut depth = 0;
+
+        while let Some(id) = current_id {
+            let info = query_map.get(&id).unwrap();
+            if info.query.name == "layout_of" {
+                depth += 1;
+                last_layout = Some((info.clone(), depth));
+            }
+            current_id = info.job.parent;
+        }
+        last_layout
+    }
 }
 
 #[cfg(parallel_compiler)]
@@ -536,46 +556,44 @@ pub(crate) fn report_cycle<'a>(
     assert!(!stack.is_empty());
 
     let span = stack[0].query.default_span(stack[1 % stack.len()].span);
-    let mut err =
-        struct_span_err!(sess, span, E0391, "cycle detected when {}", stack[0].query.description);
+
+    let mut cycle_stack = Vec::new();
+
+    use crate::error::StackCount;
+    let stack_count = if stack.len() == 1 { StackCount::Single } else { StackCount::Multiple };
 
     for i in 1..stack.len() {
         let query = &stack[i].query;
         let span = query.default_span(stack[(i + 1) % stack.len()].span);
-        err.span_note(span, &format!("...which requires {}...", query.description));
-    }
-
-    if stack.len() == 1 {
-        err.note(&format!("...which immediately requires {} again", stack[0].query.description));
-    } else {
-        err.note(&format!(
-            "...which again requires {}, completing the cycle",
-            stack[0].query.description
-        ));
-    }
-
-    if stack.iter().all(|entry| {
-        entry
-            .query
-            .def_kind
-            .map_or(false, |def_kind| matches!(def_kind, DefKind::TyAlias | DefKind::TraitAlias))
-    }) {
-        if stack.iter().all(|entry| {
-            entry.query.def_kind.map_or(false, |def_kind| matches!(def_kind, DefKind::TyAlias))
-        }) {
-            err.note("type aliases cannot be recursive");
-            err.help("consider using a struct, enum, or union instead to break the cycle");
-            err.help("see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information");
-        } else {
-            err.note("trait aliases cannot be recursive");
-        }
+        cycle_stack.push(CycleStack { span, desc: query.description.to_owned() });
     }
 
+    let mut cycle_usage = None;
     if let Some((span, query)) = usage {
-        err.span_note(query.default_span(span), &format!("cycle used when {}", query.description));
+        cycle_usage = Some(crate::error::CycleUsage {
+            span: query.default_span(span),
+            usage: query.description,
+        });
     }
 
-    err
+    let alias = if stack.iter().all(|entry| entry.query.def_kind == Some(DefKind::TyAlias)) {
+        Some(crate::error::Alias::Ty)
+    } else if stack.iter().all(|entry| entry.query.def_kind == Some(DefKind::TraitAlias)) {
+        Some(crate::error::Alias::Trait)
+    } else {
+        None
+    };
+
+    let cycle_diag = crate::error::Cycle {
+        span,
+        cycle_stack,
+        stack_bottom: stack[0].query.description.to_owned(),
+        alias,
+        cycle_usage: cycle_usage,
+        stack_count,
+    };
+
+    cycle_diag.into_diagnostic(&sess.parse_sess.span_diagnostic)
 }
 
 pub fn print_query_stack<CTX: QueryContext>(
diff --git a/compiler/rustc_query_system/src/query/mod.rs b/compiler/rustc_query_system/src/query/mod.rs
index a1f2b081d434..7a96c53b6048 100644
--- a/compiler/rustc_query_system/src/query/mod.rs
+++ b/compiler/rustc_query_system/src/query/mod.rs
@@ -14,13 +14,12 @@ pub use self::caches::{
 mod config;
 pub use self::config::{QueryConfig, QueryDescription, QueryVTable};
 
-use crate::dep_graph::{DepContext, DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
-
+use crate::dep_graph::{DepNodeIndex, HasDepContext, SerializedDepNodeIndex};
 use rustc_data_structures::sync::Lock;
-use rustc_data_structures::thin_vec::ThinVec;
 use rustc_errors::Diagnostic;
 use rustc_hir::def::DefKind;
 use rustc_span::Span;
+use thin_vec::ThinVec;
 
 /// Description of a frame in the query stack.
 ///
@@ -124,7 +123,5 @@ pub trait QueryContext: HasDepContext {
         compute: impl FnOnce() -> R,
     ) -> R;
 
-    fn depth_limit_error(&self) {
-        self.dep_context().sess().fatal("queries overflow the depth limit!");
-    }
+    fn depth_limit_error(&self, job: QueryJobId);
 }
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index 6ae9147ff774..8179a674afae 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -7,6 +7,8 @@ use crate::query::caches::QueryCache;
 use crate::query::config::{QueryDescription, QueryVTable};
 use crate::query::job::{report_cycle, QueryInfo, QueryJob, QueryJobId, QueryJobInfo};
 use crate::query::{QueryContext, QueryMap, QuerySideEffects, QueryStackFrame};
+use crate::values::Value;
+use crate::HandleCycleError;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 #[cfg(parallel_compiler)]
@@ -14,7 +16,6 @@ use rustc_data_structures::profiling::TimingGuard;
 #[cfg(parallel_compiler)]
 use rustc_data_structures::sharded::Sharded;
 use rustc_data_structures::sync::Lock;
-use rustc_data_structures::thin_vec::ThinVec;
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, FatalError};
 use rustc_session::Session;
 use rustc_span::{Span, DUMMY_SP};
@@ -24,6 +25,7 @@ use std::fmt::Debug;
 use std::hash::Hash;
 use std::mem;
 use std::ptr;
+use thin_vec::ThinVec;
 
 pub struct QueryState<K> {
     #[cfg(parallel_compiler)]
@@ -118,19 +120,46 @@ where
 fn mk_cycle<CTX, V, R>(
     tcx: CTX,
     error: CycleError,
-    handle_cycle_error: fn(CTX, DiagnosticBuilder<'_, ErrorGuaranteed>) -> V,
+    handler: HandleCycleError,
     cache: &dyn crate::query::QueryStorage<Value = V, Stored = R>,
 ) -> R
 where
     CTX: QueryContext,
-    V: std::fmt::Debug,
+    V: std::fmt::Debug + Value<CTX::DepContext>,
     R: Clone,
 {
     let error = report_cycle(tcx.dep_context().sess(), error);
-    let value = handle_cycle_error(tcx, error);
+    let value = handle_cycle_error(*tcx.dep_context(), error, handler);
     cache.store_nocache(value)
 }
 
+fn handle_cycle_error<CTX, V>(
+    tcx: CTX,
+    mut error: DiagnosticBuilder<'_, ErrorGuaranteed>,
+    handler: HandleCycleError,
+) -> V
+where
+    CTX: DepContext,
+    V: Value<CTX>,
+{
+    use HandleCycleError::*;
+    match handler {
+        Error => {
+            error.emit();
+            Value::from_cycle_error(tcx)
+        }
+        Fatal => {
+            error.emit();
+            tcx.sess().abort_if_errors();
+            unreachable!()
+        }
+        DelayBug => {
+            error.delay_as_bug();
+            Value::from_cycle_error(tcx)
+        }
+    }
+}
+
 impl<'tcx, K> JobOwner<'tcx, K>
 where
     K: Eq + Hash + Clone,
@@ -336,6 +365,7 @@ fn try_execute_query<CTX, C>(
 where
     C: QueryCache,
     C::Key: Clone + DepNodeParams<CTX::DepContext>,
+    C::Value: Value<CTX::DepContext>,
     CTX: QueryContext,
 {
     match JobOwner::<'_, C::Key>::try_start(&tcx, state, span, key.clone()) {
@@ -458,14 +488,14 @@ where
 
     // First we try to load the result from the on-disk cache.
     // Some things are never cached on disk.
-    if query.cache_on_disk {
+    if let Some(try_load_from_disk) = query.try_load_from_disk {
         let prof_timer = tcx.dep_context().profiler().incr_cache_loading();
 
         // The call to `with_query_deserialization` enforces that no new `DepNodes`
         // are created during deserialization. See the docs of that method for more
         // details.
-        let result = dep_graph
-            .with_query_deserialization(|| query.try_load_from_disk(tcx, prev_dep_node_index));
+        let result =
+            dep_graph.with_query_deserialization(|| try_load_from_disk(tcx, prev_dep_node_index));
 
         prof_timer.finish_with_query_invocation_id(dep_node_index.into());
 
@@ -618,16 +648,12 @@ fn incremental_verify_ich_cold(sess: &Session, dep_node: DebugArg<'_>, result: D
     let old_in_panic = INSIDE_VERIFY_PANIC.with(|in_panic| in_panic.replace(true));
 
     if old_in_panic {
-        sess.struct_err(
-            "internal compiler error: re-entrant incremental verify failure, suppressing message",
-        )
-        .emit();
+        sess.emit_err(crate::error::Reentrant);
     } else {
-        sess.struct_err(&format!("internal compiler error: encountered incremental compilation error with {:?}", dep_node))
-                .help(&format!("This is a known issue with the compiler. Run {} to allow your project to compile", run_cmd))
-                .note("Please follow the instructions below to create a bug report with the provided information")
-                .note("See <https://github.com/rust-lang/rust/issues/84970> for more information")
-                .emit();
+        sess.emit_err(crate::error::IncrementCompilation {
+            run_cmd,
+            dep_node: format!("{:?}", dep_node),
+        });
         panic!("Found unstable fingerprints for {:?}: {:?}", dep_node, result);
     }
 
@@ -690,6 +716,7 @@ pub fn get_query<Q, CTX>(tcx: CTX, span: Span, key: Q::Key, mode: QueryMode) ->
 where
     Q: QueryDescription<CTX>,
     Q::Key: DepNodeParams<CTX::DepContext>,
+    Q::Value: Value<CTX::DepContext>,
     CTX: QueryContext,
 {
     let query = Q::make_vtable(tcx, &key);
@@ -722,6 +749,7 @@ pub fn force_query<Q, CTX>(tcx: CTX, key: Q::Key, dep_node: DepNode<CTX::DepKind
 where
     Q: QueryDescription<CTX>,
     Q::Key: DepNodeParams<CTX::DepContext>,
+    Q::Value: Value<CTX::DepContext>,
     CTX: QueryContext,
 {
     // We may be concurrently trying both execute and force a query.
diff --git a/compiler/rustc_query_system/src/values.rs b/compiler/rustc_query_system/src/values.rs
new file mode 100644
index 000000000000..aeef66f86dac
--- /dev/null
+++ b/compiler/rustc_query_system/src/values.rs
@@ -0,0 +1,14 @@
+use crate::dep_graph::DepContext;
+
+pub trait Value<CTX: DepContext>: Sized {
+    fn from_cycle_error(tcx: CTX) -> Self;
+}
+
+impl<CTX: DepContext, T> Value<CTX> for T {
+    default fn from_cycle_error(tcx: CTX) -> T {
+        tcx.sess().abort_if_errors();
+        // Ideally we would use `bug!` here. But bug! is only defined in rustc_middle, and it's
+        // non-trivial to define it earlier.
+        panic!("Value::from_cycle_error called without errors");
+    }
+}
diff --git a/compiler/rustc_resolve/src/access_levels.rs b/compiler/rustc_resolve/src/access_levels.rs
index 3fba923d9fdf..d806441716fd 100644
--- a/compiler/rustc_resolve/src/access_levels.rs
+++ b/compiler/rustc_resolve/src/access_levels.rs
@@ -1,25 +1,20 @@
+use crate::NameBinding;
+use crate::NameBindingKind;
+use crate::Resolver;
 use rustc_ast::ast;
 use rustc_ast::visit;
 use rustc_ast::visit::Visitor;
 use rustc_ast::Crate;
 use rustc_ast::EnumDef;
-use rustc_ast::ForeignMod;
 use rustc_ast::NodeId;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::def_id::CRATE_DEF_ID;
 use rustc_middle::middle::privacy::AccessLevel;
-use rustc_middle::ty::Visibility;
+use rustc_middle::ty::DefIdTree;
 use rustc_span::sym;
 
-use crate::imports::ImportKind;
-use crate::BindingKey;
-use crate::NameBinding;
-use crate::NameBindingKind;
-use crate::Resolver;
-
 pub struct AccessLevelsVisitor<'r, 'a> {
     r: &'r mut Resolver<'a>,
-    prev_level: Option<AccessLevel>,
     changed: bool,
 }
 
@@ -28,72 +23,61 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
     /// For now, this doesn't resolve macros (FIXME) and cannot resolve Impl, as we
     /// need access to a TyCtxt for that.
     pub fn compute_access_levels<'c>(r: &'r mut Resolver<'a>, krate: &'c Crate) {
-        let mut visitor =
-            AccessLevelsVisitor { r, changed: false, prev_level: Some(AccessLevel::Public) };
+        let mut visitor = AccessLevelsVisitor { r, changed: false };
 
         visitor.set_access_level_def_id(CRATE_DEF_ID, Some(AccessLevel::Public));
-        visitor.set_exports_access_level(CRATE_DEF_ID);
+        visitor.set_bindings_access_level(CRATE_DEF_ID);
 
         while visitor.changed {
             visitor.reset();
             visit::walk_crate(&mut visitor, krate);
         }
 
-        tracing::info!("resolve::access_levels: {:#?}", r.access_levels);
+        info!("resolve::access_levels: {:#?}", r.access_levels);
     }
 
     fn reset(&mut self) {
         self.changed = false;
-        self.prev_level = Some(AccessLevel::Public);
     }
 
-    /// Update the access level of the exports of the given module accordingly. The module access
+    /// Update the access level of the bindings in the given module accordingly. The module access
     /// level has to be Exported or Public.
     /// This will also follow `use` chains (see PrivacyVisitor::set_import_binding_access_level).
-    fn set_exports_access_level(&mut self, module_id: LocalDefId) {
+    fn set_bindings_access_level(&mut self, module_id: LocalDefId) {
         assert!(self.r.module_map.contains_key(&&module_id.to_def_id()));
-
+        let module_level = self.r.access_levels.get_access_level(module_id);
+        if !module_level.is_some() {
+            return;
+        }
         // Set the given binding access level to `AccessLevel::Public` and
         // sets the rest of the `use` chain to `AccessLevel::Exported` until
         // we hit the actual exported item.
         let set_import_binding_access_level =
-            |this: &mut Self, mut binding: &NameBinding<'a>, mut access_level| {
+            |this: &mut Self, mut binding: &NameBinding<'a>, mut access_level, ns| {
                 while let NameBindingKind::Import { binding: nested_binding, import, .. } =
                     binding.kind
                 {
-                    this.set_access_level(import.id, access_level);
-                    if let ImportKind::Single { additional_ids, .. } = import.kind {
-                        this.set_access_level(additional_ids.0, access_level);
-                        this.set_access_level(additional_ids.1, access_level);
-                    }
+                    this.set_access_level(this.r.import_id_for_ns(import, ns), access_level);
 
                     access_level = Some(AccessLevel::Exported);
                     binding = nested_binding;
                 }
             };
 
-        let module_level = self.r.access_levels.map.get(&module_id).copied();
-        assert!(module_level >= Some(AccessLevel::Exported));
+        let module = self.r.get_module(module_id.to_def_id()).unwrap();
+        let resolutions = self.r.resolutions(module);
 
-        if let Some(exports) = self.r.reexport_map.get(&module_id) {
-            let pub_exports = exports
-                .iter()
-                .filter(|ex| ex.vis == Visibility::Public)
-                .cloned()
-                .collect::<Vec<_>>();
-
-            let module = self.r.get_module(module_id.to_def_id()).unwrap();
-            for export in pub_exports.into_iter() {
-                if let Some(export_def_id) = export.res.opt_def_id().and_then(|id| id.as_local()) {
-                    self.set_access_level_def_id(export_def_id, Some(AccessLevel::Exported));
-                }
-
-                if let Some(ns) = export.res.ns() {
-                    let key = BindingKey { ident: export.ident, ns, disambiguator: 0 };
-                    let name_res = self.r.resolution(module, key);
-                    if let Some(binding) = name_res.borrow().binding() {
-                        set_import_binding_access_level(self, binding, module_level)
-                    }
+        for (key, name_resolution) in resolutions.borrow().iter() {
+            if let Some(binding) = name_resolution.borrow().binding() && binding.vis.is_public() && !binding.is_ambiguity() {
+                let access_level = match binding.is_import() {
+                    true => {
+                        set_import_binding_access_level(self, binding, module_level, key.ns);
+                        Some(AccessLevel::Exported)
+                    },
+                    false => module_level,
+                };
+                if let Some(def_id) = binding.res().opt_def_id().and_then(|id| id.as_local()) {
+                    self.set_access_level_def_id(def_id, access_level);
                 }
             }
         }
@@ -114,9 +98,9 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
         def_id: LocalDefId,
         access_level: Option<AccessLevel>,
     ) -> Option<AccessLevel> {
-        let old_level = self.r.access_levels.map.get(&def_id).copied();
+        let old_level = self.r.access_levels.get_access_level(def_id);
         if old_level < access_level {
-            self.r.access_levels.map.insert(def_id, access_level.unwrap());
+            self.r.access_levels.set_access_level(def_id, access_level.unwrap());
             self.changed = true;
             access_level
         } else {
@@ -127,97 +111,59 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
 
 impl<'r, 'ast> Visitor<'ast> for AccessLevelsVisitor<'ast, 'r> {
     fn visit_item(&mut self, item: &'ast ast::Item) {
-        let inherited_item_level = match item.kind {
+        let def_id = self.r.local_def_id(item.id);
+        // Set access level of nested items.
+        // If it's a mod, also make the visitor walk all of its items
+        match item.kind {
             // Resolved in rustc_privacy when types are available
             ast::ItemKind::Impl(..) => return,
 
-            // Only exported `macro_rules!` items are public, but they always are
-            ast::ItemKind::MacroDef(ref macro_def) if macro_def.macro_rules => {
-                let is_macro_export =
-                    item.attrs.iter().any(|attr| attr.has_name(sym::macro_export));
-                if is_macro_export { Some(AccessLevel::Public) } else { None }
-            }
-
-            // Foreign modules inherit level from parents.
-            ast::ItemKind::ForeignMod(..) => self.prev_level,
-
-            // Other `pub` items inherit levels from parents.
-            ast::ItemKind::ExternCrate(..)
-            | ast::ItemKind::Use(..)
-            | ast::ItemKind::Static(..)
-            | ast::ItemKind::Const(..)
-            | ast::ItemKind::Fn(..)
-            | ast::ItemKind::Mod(..)
-            | ast::ItemKind::GlobalAsm(..)
-            | ast::ItemKind::TyAlias(..)
-            | ast::ItemKind::Enum(..)
-            | ast::ItemKind::Struct(..)
-            | ast::ItemKind::Union(..)
-            | ast::ItemKind::Trait(..)
-            | ast::ItemKind::TraitAlias(..)
-            | ast::ItemKind::MacroDef(..) => {
-                if item.vis.kind.is_pub() {
-                    self.prev_level
-                } else {
-                    None
-                }
-            }
-
             // Should be unreachable at this stage
             ast::ItemKind::MacCall(..) => panic!(
                 "ast::ItemKind::MacCall encountered, this should not anymore appear at this stage"
             ),
-        };
 
-        let access_level = self.set_access_level(item.id, inherited_item_level);
+            // Foreign modules inherit level from parents.
+            ast::ItemKind::ForeignMod(..) => {
+                let parent_level =
+                    self.r.access_levels.get_access_level(self.r.local_parent(def_id));
+                self.set_access_level(item.id, parent_level);
+            }
+
+            // Only exported `macro_rules!` items are public, but they always are
+            ast::ItemKind::MacroDef(ref macro_def) if macro_def.macro_rules => {
+                if item.attrs.iter().any(|attr| attr.has_name(sym::macro_export)) {
+                    self.set_access_level(item.id, Some(AccessLevel::Public));
+                }
+            }
 
-        // Set access level of nested items.
-        // If it's a mod, also make the visitor walk all of its items
-        match item.kind {
             ast::ItemKind::Mod(..) => {
-                if access_level.is_some() {
-                    self.set_exports_access_level(self.r.local_def_id(item.id));
-                }
-
-                let orig_level = std::mem::replace(&mut self.prev_level, access_level);
+                self.set_bindings_access_level(def_id);
                 visit::walk_item(self, item);
-                self.prev_level = orig_level;
             }
 
-            ast::ItemKind::ForeignMod(ForeignMod { ref items, .. }) => {
-                for nested in items {
-                    if nested.vis.kind.is_pub() {
-                        self.set_access_level(nested.id, access_level);
-                    }
-                }
-            }
             ast::ItemKind::Enum(EnumDef { ref variants }, _) => {
+                self.set_bindings_access_level(def_id);
                 for variant in variants {
-                    let variant_level = self.set_access_level(variant.id, access_level);
-                    if let Some(ctor_id) = variant.data.ctor_id() {
-                        self.set_access_level(ctor_id, access_level);
-                    }
-
+                    let variant_def_id = self.r.local_def_id(variant.id);
+                    let variant_level = self.r.access_levels.get_access_level(variant_def_id);
                     for field in variant.data.fields() {
                         self.set_access_level(field.id, variant_level);
                     }
                 }
             }
-            ast::ItemKind::Struct(ref def, _) | ast::ItemKind::Union(ref def, _) => {
-                if let Some(ctor_id) = def.ctor_id() {
-                    self.set_access_level(ctor_id, access_level);
-                }
 
+            ast::ItemKind::Struct(ref def, _) | ast::ItemKind::Union(ref def, _) => {
+                let inherited_level = self.r.access_levels.get_access_level(def_id);
                 for field in def.fields() {
                     if field.vis.kind.is_pub() {
-                        self.set_access_level(field.id, access_level);
+                        self.set_access_level(field.id, inherited_level);
                     }
                 }
             }
-            ast::ItemKind::Trait(ref trait_kind) => {
-                for nested in trait_kind.items.iter() {
-                    self.set_access_level(nested.id, access_level);
-                }
+
+            ast::ItemKind::Trait(..) => {
+                self.set_bindings_access_level(def_id);
             }
 
             ast::ItemKind::ExternCrate(..)
@@ -229,9 +175,6 @@ impl<'r, 'ast> Visitor<'ast> for AccessLevelsVisitor<'ast, 'r> {
             | ast::ItemKind::TraitAlias(..)
             | ast::ItemKind::MacroDef(..)
             | ast::ItemKind::Fn(..) => return,
-
-            // Unreachable kinds
-            ast::ItemKind::Impl(..) | ast::ItemKind::MacCall(..) => unreachable!(),
         }
     }
 }
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index 8f3b6009bd6e..81b67b758f7e 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -36,28 +36,29 @@ use rustc_span::Span;
 
 use std::cell::Cell;
 use std::ptr;
-use tracing::debug;
 
 type Res = def::Res<NodeId>;
 
-impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, LocalExpnId) {
+impl<'a, Id: Into<DefId>> ToNameBinding<'a>
+    for (Module<'a>, ty::Visibility<Id>, Span, LocalExpnId)
+{
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
         arenas.alloc_name_binding(NameBinding {
             kind: NameBindingKind::Module(self.0),
             ambiguity: None,
-            vis: self.1,
+            vis: self.1.to_def_id(),
             span: self.2,
             expansion: self.3,
         })
     }
 }
 
-impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, LocalExpnId) {
+impl<'a, Id: Into<DefId>> ToNameBinding<'a> for (Res, ty::Visibility<Id>, Span, LocalExpnId) {
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
         arenas.alloc_name_binding(NameBinding {
             kind: NameBindingKind::Res(self.0, false),
             ambiguity: None,
-            vis: self.1,
+            vis: self.1.to_def_id(),
             span: self.2,
             expansion: self.3,
         })
@@ -71,7 +72,7 @@ impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, LocalExpnId, IsMacroE
         arenas.alloc_name_binding(NameBinding {
             kind: NameBindingKind::Res(self.0, true),
             ambiguity: None,
-            vis: self.1,
+            vis: self.1.to_def_id(),
             span: self.2,
             expansion: self.3,
         })
@@ -261,7 +262,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         self.r.visibilities[&def_id.expect_local()]
                     }
                     // Otherwise, the visibility is restricted to the nearest parent `mod` item.
-                    _ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
+                    _ => ty::Visibility::Restricted(
+                        self.parent_scope.module.nearest_parent_mod().expect_local(),
+                    ),
                 })
             }
             ast::VisibilityKind::Restricted { ref path, id, .. } => {
@@ -312,7 +315,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                             } else {
                                 let vis = ty::Visibility::Restricted(res.def_id());
                                 if self.r.is_accessible_from(vis, parent_scope.module) {
-                                    Ok(vis)
+                                    Ok(vis.expect_local())
                                 } else {
                                     Err(VisResolutionError::AncestorOnly(path.span))
                                 }
@@ -650,7 +653,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         true,
                         // The whole `use` item
                         item,
-                        ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
+                        ty::Visibility::Restricted(
+                            self.parent_scope.module.nearest_parent_mod().expect_local(),
+                        ),
                         root_span,
                     );
                 }
@@ -766,10 +771,10 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 if let Some(ctor_node_id) = vdata.ctor_id() {
                     // If the structure is marked as non_exhaustive then lower the visibility
                     // to within the crate.
-                    let mut ctor_vis = if vis == ty::Visibility::Public
+                    let mut ctor_vis = if vis.is_public()
                         && self.r.session.contains_name(&item.attrs, sym::non_exhaustive)
                     {
-                        ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
+                        ty::Visibility::Restricted(CRATE_DEF_ID)
                     } else {
                         vis
                     };
@@ -786,7 +791,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         if ctor_vis.is_at_least(field_vis, &*self.r) {
                             ctor_vis = field_vis;
                         }
-                        ret_fields.push(field_vis);
+                        ret_fields.push(field_vis.to_def_id());
                     }
                     let ctor_def_id = self.r.local_def_id(ctor_node_id);
                     let ctor_res = Res::Def(
@@ -796,7 +801,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
                     self.r.visibilities.insert(ctor_def_id, ctor_vis);
 
-                    self.r.struct_constructors.insert(def_id, (ctor_res, ctor_vis, ret_fields));
+                    self.r
+                        .struct_constructors
+                        .insert(def_id, (ctor_res, ctor_vis.to_def_id(), ret_fields));
                 }
             }
 
@@ -868,8 +875,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         }
         .map(|module| {
             let used = self.process_macro_use_imports(item, module);
-            let binding =
-                (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
+            let vis = ty::Visibility::<LocalDefId>::Public;
+            let binding = (module, vis, sp, expansion).to_name_binding(self.r.arenas);
             (used, Some(ModuleOrUniformRoot::Module(module)), binding)
         })
         .unwrap_or((true, None, self.r.dummy_binding));
@@ -965,6 +972,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 | DefKind::TyAlias
                 | DefKind::ForeignTy
                 | DefKind::OpaqueTy
+                | DefKind::ImplTraitPlaceholder
                 | DefKind::TraitAlias
                 | DefKind::AssocTy,
                 _,
@@ -1030,7 +1038,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 self.insert_field_names(def_id, field_names);
             }
             Res::Def(DefKind::AssocFn, def_id) => {
-                if cstore.fn_has_self_parameter_untracked(def_id) {
+                if cstore.fn_has_self_parameter_untracked(def_id, self.r.session) {
                     self.r.has_self.insert(def_id);
                 }
             }
@@ -1118,7 +1126,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 root_span: span,
                 span,
                 module_path: Vec::new(),
-                vis: Cell::new(Some(ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id()))),
+                vis: Cell::new(Some(ty::Visibility::Restricted(CRATE_DEF_ID))),
                 used: Cell::new(false),
             })
         };
@@ -1264,7 +1272,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             let vis = if is_macro_export {
                 ty::Visibility::Public
             } else {
-                ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
+                ty::Visibility::Restricted(CRATE_DEF_ID)
             };
             let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
             self.r.set_binding_parent_module(binding, parent_scope.module);
@@ -1295,7 +1303,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 }
                 _ => self.resolve_visibility(&item.vis),
             };
-            if vis != ty::Visibility::Public {
+            if !vis.is_public() {
                 self.insert_unused_macro(ident, def_id, item.id, &rule_spans);
             }
             self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
@@ -1508,10 +1516,10 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
         self.r.visibilities.insert(def_id, vis);
 
         // If the variant is marked as non_exhaustive then lower the visibility to within the crate.
-        let ctor_vis = if vis == ty::Visibility::Public
+        let ctor_vis = if vis.is_public()
             && self.r.session.contains_name(&variant.attrs, sym::non_exhaustive)
         {
-            ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
+            ty::Visibility::Restricted(CRATE_DEF_ID)
         } else {
             vis
         };
diff --git a/compiler/rustc_resolve/src/def_collector.rs b/compiler/rustc_resolve/src/def_collector.rs
index 66641fb2cb24..7e83f2a72210 100644
--- a/compiler/rustc_resolve/src/def_collector.rs
+++ b/compiler/rustc_resolve/src/def_collector.rs
@@ -1,6 +1,5 @@
 use crate::{ImplTraitContext, Resolver};
 use rustc_ast::visit::{self, FnKind};
-use rustc_ast::walk_list;
 use rustc_ast::*;
 use rustc_expand::expand::AstFragment;
 use rustc_hir::def_id::LocalDefId;
@@ -8,7 +7,6 @@ use rustc_hir::definitions::*;
 use rustc_span::hygiene::LocalExpnId;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
-use tracing::debug;
 
 pub(crate) fn collect_definitions(
     resolver: &mut Resolver<'_>,
@@ -149,13 +147,18 @@ impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
                 self.with_parent(return_impl_trait_id, |this| {
                     this.visit_fn_ret_ty(&sig.decl.output)
                 });
-                let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
-                self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
+                // If this async fn has no body (i.e. it's an async fn signature in a trait)
+                // then the closure_def will never be used, and we should avoid generating a
+                // def-id for it.
+                if let Some(body) = body {
+                    let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
+                    self.with_parent(closure_def, |this| this.visit_block(body));
+                }
                 return;
             }
         }
 
-        visit::walk_fn(self, fn_kind, span);
+        visit::walk_fn(self, fn_kind);
     }
 
     fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 2d15b1b0a1b9..ab71fa0bc1d4 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -25,7 +25,6 @@ use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Span};
-use tracing::debug;
 
 use crate::imports::{Import, ImportKind, ImportResolver};
 use crate::late::{PatternSource, Rib};
@@ -1394,7 +1393,7 @@ impl<'a> Resolver<'a> {
 
         // If only some candidates are accessible, take just them
         if !candidates.iter().all(|v: &ImportSuggestion| !v.accessible) {
-            candidates = candidates.into_iter().filter(|x| x.accessible).collect();
+            candidates.retain(|x| x.accessible)
         }
 
         candidates
diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index 2afba94d793a..2287aa1eb256 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -6,6 +6,7 @@ use rustc_middle::bug;
 use rustc_middle::ty;
 use rustc_session::lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK;
 use rustc_session::lint::BuiltinLintDiagnostics;
+use rustc_span::def_id::LocalDefId;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext};
 use rustc_span::symbol::{kw, Ident};
@@ -26,6 +27,8 @@ use Determinacy::*;
 use Namespace::*;
 use RibKind::*;
 
+type Visibility = ty::Visibility<LocalDefId>;
+
 impl<'a> Resolver<'a> {
     /// A generic scope visitor.
     /// Visits scopes in order to resolve some identifier in them or perform other actions.
@@ -273,7 +276,7 @@ impl<'a> Resolver<'a> {
     ///
     /// Invariant: This must only be called during main resolution, not during
     /// import resolution.
-    #[tracing::instrument(level = "debug", skip(self, ribs))]
+    #[instrument(level = "debug", skip(self, ribs))]
     pub(crate) fn resolve_ident_in_lexical_scope(
         &mut self,
         mut ident: Ident,
@@ -367,7 +370,7 @@ impl<'a> Resolver<'a> {
     /// expansion and import resolution (perhaps they can be merged in the future).
     /// The function is used for resolving initial segments of macro paths (e.g., `foo` in
     /// `foo::bar!(); or `foo!();`) and also for import paths on 2018 edition.
-    #[tracing::instrument(level = "debug", skip(self, scope_set))]
+    #[instrument(level = "debug", skip(self, scope_set))]
     pub(crate) fn early_resolve_ident_in_lexical_scope(
         &mut self,
         orig_ident: Ident,
@@ -424,8 +427,7 @@ impl<'a> Resolver<'a> {
                 let ident = Ident::new(orig_ident.name, orig_ident.span.with_ctxt(ctxt));
                 let ok = |res, span, arenas| {
                     Ok((
-                        (res, ty::Visibility::Public, span, LocalExpnId::ROOT)
-                            .to_name_binding(arenas),
+                        (res, Visibility::Public, span, LocalExpnId::ROOT).to_name_binding(arenas),
                         Flags::empty(),
                     ))
                 };
@@ -438,7 +440,7 @@ impl<'a> Resolver<'a> {
                         {
                             let binding = (
                                 Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper),
-                                ty::Visibility::Public,
+                                Visibility::Public,
                                 attr.span,
                                 expn_id,
                             )
@@ -708,7 +710,7 @@ impl<'a> Resolver<'a> {
         Err(Determinacy::determined(determinacy == Determinacy::Determined || force))
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn maybe_resolve_ident_in_module(
         &mut self,
         module: ModuleOrUniformRoot<'a>,
@@ -720,7 +722,7 @@ impl<'a> Resolver<'a> {
             .map_err(|(determinacy, _)| determinacy)
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn resolve_ident_in_module(
         &mut self,
         module: ModuleOrUniformRoot<'a>,
@@ -734,7 +736,7 @@ impl<'a> Resolver<'a> {
             .map_err(|(determinacy, _)| determinacy)
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_ident_in_module_ext(
         &mut self,
         module: ModuleOrUniformRoot<'a>,
@@ -772,7 +774,7 @@ impl<'a> Resolver<'a> {
         )
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_ident_in_module_unadjusted(
         &mut self,
         module: ModuleOrUniformRoot<'a>,
@@ -796,7 +798,7 @@ impl<'a> Resolver<'a> {
 
     /// Attempts to resolve `ident` in namespaces `ns` of `module`.
     /// Invariant: if `finalize` is `Some`, expansion and import resolution must be complete.
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_ident_in_module_unadjusted_ext(
         &mut self,
         module: ModuleOrUniformRoot<'a>,
@@ -841,9 +843,8 @@ impl<'a> Resolver<'a> {
                 if ns == TypeNS {
                     if ident.name == kw::Crate || ident.name == kw::DollarCrate {
                         let module = self.resolve_crate_root(ident);
-                        let binding =
-                            (module, ty::Visibility::Public, module.span, LocalExpnId::ROOT)
-                                .to_name_binding(self.arenas);
+                        let binding = (module, Visibility::Public, module.span, LocalExpnId::ROOT)
+                            .to_name_binding(self.arenas);
                         return Ok(binding);
                     } else if ident.name == kw::Super || ident.name == kw::SelfLower {
                         // FIXME: Implement these with renaming requirements so that e.g.
@@ -1059,7 +1060,7 @@ impl<'a> Resolver<'a> {
     }
 
     /// Validate a local resolution (from ribs).
-    #[tracing::instrument(level = "debug", skip(self, all_ribs))]
+    #[instrument(level = "debug", skip(self, all_ribs))]
     fn validate_res_from_ribs(
         &mut self,
         rib_index: usize,
@@ -1294,7 +1295,7 @@ impl<'a> Resolver<'a> {
         res
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn maybe_resolve_path(
         &mut self,
         path: &[Segment],
@@ -1304,7 +1305,7 @@ impl<'a> Resolver<'a> {
         self.resolve_path_with_ribs(path, opt_ns, parent_scope, None, None, None)
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn resolve_path(
         &mut self,
         path: &[Segment],
diff --git a/compiler/rustc_resolve/src/imports.rs b/compiler/rustc_resolve/src/imports.rs
index c2491c6ebdec..5bdb42747819 100644
--- a/compiler/rustc_resolve/src/imports.rs
+++ b/compiler/rustc_resolve/src/imports.rs
@@ -2,7 +2,7 @@
 
 use crate::diagnostics::Suggestion;
 use crate::Determinacy::{self, *};
-use crate::Namespace::{MacroNS, TypeNS};
+use crate::Namespace::{self, *};
 use crate::{module_to_string, names_to_string};
 use crate::{AmbiguityKind, BindingKey, ModuleKind, ResolutionError, Resolver, Segment};
 use crate::{Finalize, Module, ModuleOrUniformRoot, ParentScope, PerNS, ScopeSet};
@@ -23,8 +23,6 @@ use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::symbol::{kw, Ident, Symbol};
 use rustc_span::Span;
 
-use tracing::*;
-
 use std::cell::Cell;
 use std::{mem, ptr};
 
@@ -216,7 +214,7 @@ impl<'a> Resolver<'a> {
         binding: &'a NameBinding<'a>,
         import: &'a Import<'a>,
     ) -> &'a NameBinding<'a> {
-        let import_vis = import.expect_vis();
+        let import_vis = import.expect_vis().to_def_id();
         let vis = if binding.vis.is_at_least(import_vis, self)
             || pub_use_of_private_extern_crate_hack(import, binding)
         {
@@ -229,7 +227,7 @@ impl<'a> Resolver<'a> {
             if vis == import_vis
                 || max_vis.get().map_or(true, |max_vis| vis.is_at_least(max_vis, self))
             {
-                max_vis.set(Some(vis))
+                max_vis.set(Some(vis.expect_local()))
             }
         }
 
@@ -373,6 +371,31 @@ impl<'a> Resolver<'a> {
             self.used_imports.insert(import.id);
         }
     }
+
+    /// Take primary and additional node IDs from an import and select one that corresponds to the
+    /// given namespace. The logic must match the corresponding logic from `fn lower_use_tree` that
+    /// assigns resolutons to IDs.
+    pub(crate) fn import_id_for_ns(&self, import: &Import<'_>, ns: Namespace) -> NodeId {
+        if let ImportKind::Single { additional_ids: (id1, id2), .. } = import.kind {
+            if let Some(resolutions) = self.import_res_map.get(&import.id) {
+                assert!(resolutions[ns].is_some(), "incorrectly finalized import");
+                return match ns {
+                    TypeNS => import.id,
+                    ValueNS => match resolutions.type_ns {
+                        Some(_) => id1,
+                        None => import.id,
+                    },
+                    MacroNS => match (resolutions.type_ns, resolutions.value_ns) {
+                        (Some(_), Some(_)) => id2,
+                        (Some(_), None) | (None, Some(_)) => id1,
+                        (None, None) => import.id,
+                    },
+                };
+            }
+        }
+
+        import.id
+    }
 }
 
 /// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved
@@ -1135,24 +1158,15 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         if let Some(def_id) = module.opt_def_id() {
             let mut reexports = Vec::new();
 
-            module.for_each_child(self.r, |_, ident, _, binding| {
-                // FIXME: Consider changing the binding inserted by `#[macro_export] macro_rules`
-                // into the crate root to actual `NameBindingKind::Import`.
-                if binding.is_import()
-                    || matches!(binding.kind, NameBindingKind::Res(_, _is_macro_export @ true))
-                {
-                    let res = binding.res().expect_non_local();
-                    // Ambiguous imports are treated as errors at this point and are
-                    // not exposed to other crates (see #36837 for more details).
-                    if res != def::Res::Err && !binding.is_ambiguity() {
-                        reexports.push(ModChild {
-                            ident,
-                            res,
-                            vis: binding.vis,
-                            span: binding.span,
-                            macro_rules: false,
-                        });
-                    }
+            module.for_each_child(self.r, |this, ident, _, binding| {
+                if let Some(res) = this.is_reexport(binding) {
+                    reexports.push(ModChild {
+                        ident,
+                        res,
+                        vis: binding.vis,
+                        span: binding.span,
+                        macro_rules: false,
+                    });
                 }
             });
 
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 693ec86616ee..558db003867d 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -20,7 +20,7 @@ use rustc_errors::DiagnosticId;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, PartialRes, PerNS};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
-use rustc_hir::{PrimTy, TraitCandidate};
+use rustc_hir::{BindingAnnotation, PrimTy, TraitCandidate};
 use rustc_middle::middle::resolve_lifetime::Set1;
 use rustc_middle::ty::DefIdTree;
 use rustc_middle::{bug, span_bug};
@@ -32,7 +32,6 @@ use smallvec::{smallvec, SmallVec};
 use rustc_span::source_map::{respan, Spanned};
 use std::collections::{hash_map::Entry, BTreeSet};
 use std::mem::{replace, take};
-use tracing::debug;
 
 mod diagnostics;
 pub(crate) mod lifetimes;
@@ -51,7 +50,7 @@ use diagnostics::{
 #[derive(Copy, Clone, Debug)]
 struct BindingInfo {
     span: Span,
-    binding_mode: BindingMode,
+    annotation: BindingAnnotation,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
@@ -806,7 +805,12 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
                             sig.decl.has_self(),
                             sig.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
                             &sig.decl.output,
-                        )
+                        );
+
+                        this.record_lifetime_params_for_async(
+                            fn_id,
+                            sig.header.asyncness.opt_return_id(),
+                        );
                     },
                 );
                 return;
@@ -848,41 +852,7 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
                             },
                         );
 
-                        // Construct the list of in-scope lifetime parameters for async lowering.
-                        // We include all lifetime parameters, either named or "Fresh".
-                        // The order of those parameters does not matter, as long as it is
-                        // deterministic.
-                        if let Some(async_node_id) = async_node_id {
-                            let mut extra_lifetime_params = this
-                                .r
-                                .extra_lifetime_params_map
-                                .get(&fn_id)
-                                .cloned()
-                                .unwrap_or_default();
-                            for rib in this.lifetime_ribs.iter().rev() {
-                                extra_lifetime_params.extend(
-                                    rib.bindings
-                                        .iter()
-                                        .map(|(&ident, &(node_id, res))| (ident, node_id, res)),
-                                );
-                                match rib.kind {
-                                    LifetimeRibKind::Item => break,
-                                    LifetimeRibKind::AnonymousCreateParameter {
-                                        binder, ..
-                                    } => {
-                                        if let Some(earlier_fresh) =
-                                            this.r.extra_lifetime_params_map.get(&binder)
-                                        {
-                                            extra_lifetime_params.extend(earlier_fresh);
-                                        }
-                                    }
-                                    _ => {}
-                                }
-                            }
-                            this.r
-                                .extra_lifetime_params_map
-                                .insert(async_node_id, extra_lifetime_params);
-                        }
+                        this.record_lifetime_params_for_async(fn_id, async_node_id);
 
                         if let Some(body) = body {
                             // Ignore errors in function bodies if this is rustdoc
@@ -1031,7 +1001,7 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         if let Some(ref gen_args) = constraint.gen_args {
             // Forbid anonymous lifetimes in GAT parameters until proper semantics are decided.
             self.with_lifetime_rib(LifetimeRibKind::AnonymousReportError, |this| {
-                this.visit_generic_args(gen_args.span(), gen_args)
+                this.visit_generic_args(gen_args)
             });
         }
         match constraint.kind {
@@ -1045,10 +1015,10 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         }
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
+    fn visit_path_segment(&mut self, path_segment: &'ast PathSegment) {
         if let Some(ref args) = path_segment.args {
             match &**args {
-                GenericArgs::AngleBracketed(..) => visit::walk_generic_args(self, path_span, args),
+                GenericArgs::AngleBracketed(..) => visit::walk_generic_args(self, args),
                 GenericArgs::Parenthesized(p_args) => {
                     // Probe the lifetime ribs to know how to behave.
                     for rib in self.lifetime_ribs.iter().rev() {
@@ -1079,7 +1049,7 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
                             // We have nowhere to introduce generics.  Code is malformed,
                             // so use regular lifetime resolution to avoid spurious errors.
                             LifetimeRibKind::Item | LifetimeRibKind::Generics { .. } => {
-                                visit::walk_generic_args(self, path_span, args);
+                                visit::walk_generic_args(self, args);
                                 break;
                             }
                             LifetimeRibKind::AnonymousCreateParameter { .. }
@@ -1390,7 +1360,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         })
     }
 
-    #[tracing::instrument(level = "debug", skip(self, work))]
+    #[instrument(level = "debug", skip(self, work))]
     fn with_lifetime_rib<T>(
         &mut self,
         kind: LifetimeRibKind,
@@ -1404,7 +1374,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         ret
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_lifetime(&mut self, lifetime: &'ast Lifetime, use_ctxt: visit::LifetimeCtxt) {
         let ident = lifetime.ident;
 
@@ -1508,7 +1478,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         self.record_lifetime_res(lifetime.id, LifetimeRes::Error, LifetimeElisionCandidate::Named);
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_anonymous_lifetime(&mut self, lifetime: &Lifetime, elided: bool) {
         debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
 
@@ -1573,7 +1543,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         self.report_missing_lifetime_specifiers(vec![missing_lifetime], None);
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_elided_lifetime(&mut self, anchor_id: NodeId, span: Span) {
         let id = self.r.next_node_id();
         let lt = Lifetime { id, ident: Ident::new(kw::UnderscoreLifetime, span) };
@@ -1586,7 +1556,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         self.resolve_anonymous_lifetime(&lt, true);
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn create_fresh_lifetime(&mut self, id: NodeId, ident: Ident, binder: NodeId) -> LifetimeRes {
         debug_assert_eq!(ident.name, kw::UnderscoreLifetime);
         debug!(?ident.span);
@@ -1604,7 +1574,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         res
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_elided_lifetimes_in_path(
         &mut self,
         path_id: NodeId,
@@ -1804,7 +1774,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn record_lifetime_res(
         &mut self,
         id: NodeId,
@@ -1827,7 +1797,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn record_lifetime_param(&mut self, id: NodeId, res: LifetimeRes) {
         if let Some(prev_res) = self.r.lifetimes_res_map.insert(id, res) {
             panic!(
@@ -1838,7 +1808,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     }
 
     /// Perform resolution of a function signature, accounting for lifetime elision.
-    #[tracing::instrument(level = "debug", skip(self, inputs))]
+    #[instrument(level = "debug", skip(self, inputs))]
     fn resolve_fn_signature(
         &mut self,
         fn_id: NodeId,
@@ -2866,10 +2836,10 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
         pat.walk(&mut |pat| {
             match pat.kind {
-                PatKind::Ident(binding_mode, ident, ref sub_pat)
+                PatKind::Ident(annotation, ident, ref sub_pat)
                     if sub_pat.is_some() || self.is_base_res_local(pat.id) =>
                 {
-                    binding_map.insert(ident, BindingInfo { span: ident.span, binding_mode });
+                    binding_map.insert(ident, BindingInfo { span: ident.span, annotation });
                 }
                 PatKind::Or(ref ps) => {
                     // Check the consistency of this or-pattern and
@@ -2926,7 +2896,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                         binding_error.target.insert(pat_outer.span);
                     }
                     Some(binding_outer) => {
-                        if binding_outer.binding_mode != binding_inner.binding_mode {
+                        if binding_outer.annotation != binding_inner.annotation {
                             // The binding modes in the outer and inner bindings differ.
                             inconsistent_vars
                                 .entry(name)
@@ -3147,14 +3117,14 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     fn try_resolve_as_non_binding(
         &mut self,
         pat_src: PatternSource,
-        bm: BindingMode,
+        ann: BindingAnnotation,
         ident: Ident,
         has_sub: bool,
     ) -> Option<Res> {
         // An immutable (no `mut`) by-value (no `ref`) binding pattern without
         // a sub pattern (no `@ $pat`) is syntactically ambiguous as it could
         // also be interpreted as a path to e.g. a constant, variant, etc.
-        let is_syntactic_ambiguity = !has_sub && bm == BindingMode::ByValue(Mutability::Not);
+        let is_syntactic_ambiguity = !has_sub && ann == BindingAnnotation::NONE;
 
         let ls_binding = self.maybe_resolve_ident_in_lexical_scope(ident, ValueNS)?;
         let (res, binding) = match ls_binding {
@@ -3268,11 +3238,9 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         source: PathSource<'ast>,
         finalize: Finalize,
     ) -> PartialRes {
-        tracing::debug!(
+        debug!(
             "smart_resolve_path_fragment(qself={:?}, path={:?}, finalize={:?})",
-            qself,
-            path,
-            finalize,
+            qself, path, finalize,
         );
         let ns = source.namespace();
 
@@ -3801,7 +3769,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 for argument in arguments {
                     self.resolve_expr(argument, None);
                 }
-                self.visit_path_segment(expr.span, segment);
+                self.visit_path_segment(segment);
             }
 
             ExprKind::Call(ref callee, ref arguments) => {
@@ -3929,6 +3897,36 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             Some((ident.name, ns)),
         )
     }
+
+    /// Construct the list of in-scope lifetime parameters for async lowering.
+    /// We include all lifetime parameters, either named or "Fresh".
+    /// The order of those parameters does not matter, as long as it is
+    /// deterministic.
+    fn record_lifetime_params_for_async(
+        &mut self,
+        fn_id: NodeId,
+        async_node_id: Option<(NodeId, Span)>,
+    ) {
+        if let Some((async_node_id, _)) = async_node_id {
+            let mut extra_lifetime_params =
+                self.r.extra_lifetime_params_map.get(&fn_id).cloned().unwrap_or_default();
+            for rib in self.lifetime_ribs.iter().rev() {
+                extra_lifetime_params.extend(
+                    rib.bindings.iter().map(|(&ident, &(node_id, res))| (ident, node_id, res)),
+                );
+                match rib.kind {
+                    LifetimeRibKind::Item => break,
+                    LifetimeRibKind::AnonymousCreateParameter { binder, .. } => {
+                        if let Some(earlier_fresh) = self.r.extra_lifetime_params_map.get(&binder) {
+                            extra_lifetime_params.extend(earlier_fresh);
+                        }
+                    }
+                    _ => {}
+                }
+            }
+            self.r.extra_lifetime_params_map.insert(async_node_id, extra_lifetime_params);
+        }
+    }
 }
 
 struct LifetimeCountVisitor<'a, 'b> {
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index d41edea6a256..3c276a9ada97 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -33,8 +33,6 @@ use rustc_span::{BytePos, Span};
 use std::iter;
 use std::ops::Deref;
 
-use tracing::debug;
-
 type Res = def::Res<ast::NodeId>;
 
 /// A field or associated item from self type suggested in case of resolution failure.
@@ -175,7 +173,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 span,
                 span_label: match res {
                     Res::Def(kind, def_id) if kind == DefKind::TyParam => {
-                        self.def_span(def_id).map(|span| (span, "found this type pararmeter"))
+                        self.def_span(def_id).map(|span| (span, "found this type parameter"))
                     }
                     _ => None,
                 },
@@ -619,9 +617,9 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                         .filter(|&sp| sp != base_error.span)
                         .collect();
 
-                    let start_span = bounds.iter().map(|bound| bound.span()).next().unwrap();
+                    let start_span = bounds[0].span();
                     // `end_span` is the end of the poly trait ref (Foo + 'baz + Bar><)
-                    let end_span = bounds.iter().map(|bound| bound.span()).last().unwrap();
+                    let end_span = bounds.last().unwrap().span();
                     // `last_bound_span` is the last bound of the poly trait ref (Foo + >'baz< + Bar)
                     let last_bound_span = spans.last().cloned().unwrap();
                     let mut multi_span: MultiSpan = spans.clone().into();
@@ -1792,7 +1790,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 }
             };
 
-            let mut suggestable_variants = variants
+            let suggestable_variants = variants
                 .iter()
                 .filter(|(_, def_id, kind)| !needs_placeholder(*def_id, *kind))
                 .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
@@ -1802,8 +1800,9 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     CtorKind::Fictive => format!("({} {{}})", variant),
                 })
                 .collect::<Vec<_>>();
+            let no_suggestable_variant = suggestable_variants.is_empty();
 
-            if !suggestable_variants.is_empty() {
+            if !no_suggestable_variant {
                 let msg = if suggestable_variants.len() == 1 {
                     "you might have meant to use the following enum variant"
                 } else {
@@ -1813,7 +1812,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 err.span_suggestions(
                     span,
                     msg,
-                    suggestable_variants.drain(..),
+                    suggestable_variants.into_iter(),
                     Applicability::MaybeIncorrect,
                 );
             }
@@ -1830,15 +1829,15 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 .collect::<Vec<_>>();
 
             if !suggestable_variants_with_placeholders.is_empty() {
-                let msg = match (
-                    suggestable_variants.is_empty(),
-                    suggestable_variants_with_placeholders.len(),
-                ) {
-                    (true, 1) => "the following enum variant is available",
-                    (true, _) => "the following enum variants are available",
-                    (false, 1) => "alternatively, the following enum variant is available",
-                    (false, _) => "alternatively, the following enum variants are also available",
-                };
+                let msg =
+                    match (no_suggestable_variant, suggestable_variants_with_placeholders.len()) {
+                        (true, 1) => "the following enum variant is available",
+                        (true, _) => "the following enum variants are available",
+                        (false, 1) => "alternatively, the following enum variant is available",
+                        (false, _) => {
+                            "alternatively, the following enum variants are also available"
+                        }
+                    };
 
                 err.span_suggestions(
                     span,
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 6ea976a59006..9fb1af20ac97 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -278,7 +278,7 @@ pub fn provide(providers: &mut ty::query::Providers) {
 /// lifetimes into a single binder.) This requires us to resolve the
 /// *trait definition* of `Sub`; basically just enough lifetime information
 /// to look at the supertraits.
-#[tracing::instrument(level = "debug", skip(tcx))]
+#[instrument(level = "debug", skip(tcx))]
 fn resolve_lifetimes_trait_definition(
     tcx: TyCtxt<'_>,
     local_def_id: LocalDefId,
@@ -289,7 +289,7 @@ fn resolve_lifetimes_trait_definition(
 /// Computes the `ResolveLifetimes` map that contains data for an entire `Item`.
 /// You should not read the result of this query directly, but rather use
 /// `named_region_map`, `is_late_bound_map`, etc.
-#[tracing::instrument(level = "debug", skip(tcx))]
+#[instrument(level = "debug", skip(tcx))]
 fn resolve_lifetimes(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> ResolveLifetimes {
     convert_named_region_map(do_resolve(tcx, local_def_id, false))
 }
@@ -339,24 +339,25 @@ fn convert_named_region_map(named_region_map: NamedRegionMap) -> ResolveLifetime
 /// This allows us to avoid cycles. Importantly, if we ask for lifetimes for lifetimes that have an owner
 /// other than the trait itself (like the trait methods or associated types), then we just use the regular
 /// `resolve_lifetimes`.
-fn resolve_lifetimes_for<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &'tcx ResolveLifetimes {
-    let item_id = item_for(tcx, def_id);
-    if item_id == def_id {
-        let item = tcx.hir().item(hir::ItemId { def_id: item_id });
+fn resolve_lifetimes_for<'tcx>(tcx: TyCtxt<'tcx>, def_id: hir::OwnerId) -> &'tcx ResolveLifetimes {
+    let item_id = item_for(tcx, def_id.def_id);
+    let local_def_id = item_id.def_id.def_id;
+    if item_id.def_id == def_id {
+        let item = tcx.hir().item(item_id);
         match item.kind {
-            hir::ItemKind::Trait(..) => tcx.resolve_lifetimes_trait_definition(item_id),
-            _ => tcx.resolve_lifetimes(item_id),
+            hir::ItemKind::Trait(..) => tcx.resolve_lifetimes_trait_definition(local_def_id),
+            _ => tcx.resolve_lifetimes(local_def_id),
         }
     } else {
-        tcx.resolve_lifetimes(item_id)
+        tcx.resolve_lifetimes(local_def_id)
     }
 }
 
 /// Finds the `Item` that contains the given `LocalDefId`
-fn item_for(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> LocalDefId {
+fn item_for(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> hir::ItemId {
     match tcx.hir().find_by_def_id(local_def_id) {
         Some(Node::Item(item)) => {
-            return item.def_id;
+            return item.item_id();
         }
         _ => {}
     }
@@ -366,7 +367,7 @@ fn item_for(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> LocalDefId {
         loop {
             let node = parent_iter.next().map(|n| n.1);
             match node {
-                Some(hir::Node::Item(item)) => break item.def_id,
+                Some(hir::Node::Item(item)) => break item.item_id(),
                 Some(hir::Node::Crate(_)) | None => bug!("Called `item_for` on an Item."),
                 _ => {}
             }
@@ -525,6 +526,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
         match &item.kind {
             hir::ItemKind::Impl(hir::Impl { of_trait, .. }) => {
@@ -565,13 +567,12 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 // their owner, we can keep going until we find the Item that owns that. We then
                 // conservatively add all resolved lifetimes. Otherwise we run into problems in
                 // cases like `type Foo<'a> = impl Bar<As = impl Baz + 'a>`.
-                for (_hir_id, node) in
-                    self.tcx.hir().parent_iter(self.tcx.hir().local_def_id_to_hir_id(item.def_id))
-                {
+                for (_hir_id, node) in self.tcx.hir().parent_iter(item.def_id.into()) {
                     match node {
                         hir::Node::Item(parent_item) => {
-                            let resolved_lifetimes: &ResolveLifetimes =
-                                self.tcx.resolve_lifetimes(item_for(self.tcx, parent_item.def_id));
+                            let resolved_lifetimes: &ResolveLifetimes = self.tcx.resolve_lifetimes(
+                                item_for(self.tcx, parent_item.def_id.def_id).def_id.def_id,
+                            );
                             // We need to add *all* deps, since opaque tys may want them from *us*
                             for (&owner, defs) in resolved_lifetimes.defs.iter() {
                                 defs.iter().for_each(|(&local_id, region)| {
@@ -647,7 +648,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
         match ty.kind {
             hir::TyKind::BareFn(ref c) => {
@@ -681,7 +682,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 let scope = Scope::TraitRefBoundary { s: self.scope };
                 self.with(scope, |this| {
                     for bound in bounds {
-                        this.visit_poly_trait_ref(bound, hir::TraitBoundModifier::None);
+                        this.visit_poly_trait_ref(bound);
                     }
                 });
                 match lifetime.name {
@@ -714,7 +715,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 };
                 self.with(scope, |this| this.visit_ty(&mt.ty));
             }
-            hir::TyKind::OpaqueDef(item_id, lifetimes) => {
+            hir::TyKind::OpaqueDef(item_id, lifetimes, _in_trait) => {
                 // Resolve the lifetimes in the bounds to the lifetime defs in the generics.
                 // `fn foo<'a>() -> impl MyTrait<'a> { ... }` desugars to
                 // `type MyAnonTy<'b> = impl MyTrait<'b>;`
@@ -839,6 +840,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
         use self::hir::TraitItemKind::*;
         match trait_item.kind {
@@ -888,6 +890,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
         use self::hir::ImplItemKind::*;
         match impl_item.kind {
@@ -930,7 +933,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime) {
         match lifetime_ref.name {
             hir::LifetimeName::Static => self.insert_lifetime(lifetime_ref, Region::Static),
@@ -1102,11 +1105,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         }
     }
 
-    fn visit_poly_trait_ref(
-        &mut self,
-        trait_ref: &'tcx hir::PolyTraitRef<'tcx>,
-        _modifier: hir::TraitBoundModifier,
-    ) {
+    fn visit_poly_trait_ref(&mut self, trait_ref: &'tcx hir::PolyTraitRef<'tcx>) {
         debug!("visit_poly_trait_ref(trait_ref={:?})", trait_ref);
 
         let (mut binders, scope_type) = self.poly_trait_ref_binder_info();
@@ -1148,21 +1147,18 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     }
 }
 
-fn object_lifetime_default<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    param_def_id: DefId,
-) -> Option<ObjectLifetimeDefault> {
+fn object_lifetime_default<'tcx>(tcx: TyCtxt<'tcx>, param_def_id: DefId) -> ObjectLifetimeDefault {
+    debug_assert_eq!(tcx.def_kind(param_def_id), DefKind::TyParam);
     let param_def_id = param_def_id.expect_local();
     let parent_def_id = tcx.local_parent(param_def_id);
-    let generics = tcx.hir().get_generics(parent_def_id)?;
+    let generics = tcx.hir().get_generics(parent_def_id).unwrap();
     let param_hir_id = tcx.local_def_id_to_hir_id(param_def_id);
-    let param = generics.params.iter().find(|p| p.hir_id == param_hir_id)?;
+    let param = generics.params.iter().find(|p| p.hir_id == param_hir_id).unwrap();
 
     // Scan the bounds and where-clauses on parameters to extract bounds
     // of the form `T:'a` so as to determine the `ObjectLifetimeDefault`
     // for each type parameter.
     match param.kind {
-        GenericParamKind::Lifetime { .. } => None,
         GenericParamKind::Type { .. } => {
             let mut set = Set1::Empty;
 
@@ -1181,21 +1177,17 @@ fn object_lifetime_default<'tcx>(
                 }
             }
 
-            Some(match set {
+            match set {
                 Set1::Empty => ObjectLifetimeDefault::Empty,
                 Set1::One(hir::LifetimeName::Static) => ObjectLifetimeDefault::Static,
                 Set1::One(hir::LifetimeName::Param(param_def_id, _)) => {
                     ObjectLifetimeDefault::Param(param_def_id.to_def_id())
                 }
                 _ => ObjectLifetimeDefault::Ambiguous,
-            })
+            }
         }
-        GenericParamKind::Const { .. } => {
-            // Generic consts don't impose any constraints.
-            //
-            // We still store a dummy value here to allow generic parameters
-            // in an arbitrary order.
-            Some(ObjectLifetimeDefault::Empty)
+        _ => {
+            bug!("object_lifetime_default_raw must only be called on a type parameter")
         }
     }
 }
@@ -1212,7 +1204,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             scope: &wrap_scope,
             trait_definition_only: self.trait_definition_only,
         };
-        let span = tracing::debug_span!("scope", scope = ?TruncatedScopeDebug(&this.scope));
+        let span = debug_span!("scope", scope = ?TruncatedScopeDebug(&this.scope));
         {
             let _enter = span.enter();
             f(&mut this);
@@ -1287,7 +1279,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         self.with(scope, walk);
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn resolve_lifetime_ref(
         &mut self,
         region_def_id: LocalDefId,
@@ -1323,7 +1315,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                     // regular fns.
                     if let Some(hir::PredicateOrigin::ImplTrait) = where_bound_origin
                         && let hir::LifetimeName::Param(_, hir::ParamName::Fresh) = lifetime_ref.name
-                        && let hir::IsAsync::NotAsync = self.tcx.asyncness(lifetime_ref.hir_id.owner)
+                        && let hir::IsAsync::NotAsync = self.tcx.asyncness(lifetime_ref.hir_id.owner.def_id)
                         && !self.tcx.features().anonymous_lifetime_in_impl_trait
                     {
                         rustc_session::parse::feature_err(
@@ -1368,7 +1360,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             return;
         }
 
-        // We may fail to resolve higher-ranked lifetimes that are mentionned by APIT.
+        // We may fail to resolve higher-ranked lifetimes that are mentioned by APIT.
         // AST-based resolution does not care for impl-trait desugaring, which are the
         // responibility of lowering.  This may create a mismatch between the resolution
         // AST found (`region_def_id`) which points to HRTB, and what HIR allows.
@@ -1409,7 +1401,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         );
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_segment_args(
         &mut self,
         res: Res,
@@ -1512,7 +1504,20 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             generics
                 .params
                 .iter()
-                .filter_map(|param| self.tcx.object_lifetime_default(param.def_id))
+                .filter_map(|param| {
+                    match self.tcx.def_kind(param.def_id) {
+                        // Generic consts don't impose any constraints.
+                        //
+                        // We still store a dummy value here to allow generic parameters
+                        // in an arbitrary order.
+                        DefKind::ConstParam => Some(ObjectLifetimeDefault::Empty),
+                        DefKind::TyParam => Some(self.tcx.object_lifetime_default(param.def_id)),
+                        // We may also get a `Trait` or `TraitAlias` because of how generics `Self` parameter
+                        // works.  Ignore it because it can't have a meaningful lifetime default.
+                        DefKind::LifetimeParam | DefKind::Trait | DefKind::TraitAlias => None,
+                        dk => bug!("unexpected def_kind {:?}", dk),
+                    }
+                })
                 .map(set_to_region)
                 .collect()
         });
@@ -1659,7 +1664,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn visit_fn_like_elision(
         &mut self,
         inputs: &'tcx [hir::Ty<'tcx>],
@@ -1707,7 +1712,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         self.insert_lifetime(lifetime_ref, lifetime.shifted(late_depth));
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self))]
     fn insert_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime, def: Region) {
         debug!(
             node = ?self.tcx.hir().node_to_string(lifetime_ref.hir_id),
@@ -1818,7 +1823,7 @@ fn is_late_bound_map(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<&FxIndexSet<
                     // is, those would be potentially inputs to
                     // projections
                     if let Some(last_segment) = path.segments.last() {
-                        self.visit_path_segment(path.span, last_segment);
+                        self.visit_path_segment(last_segment);
                     }
                 }
 
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 66090c96d1ee..583030b0e504 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -12,7 +12,6 @@
 #![feature(if_let_guard)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustdoc::private_intra_doc_links)]
@@ -57,8 +56,7 @@ use rustc_span::{Span, DUMMY_SP};
 use smallvec::{smallvec, SmallVec};
 use std::cell::{Cell, RefCell};
 use std::collections::BTreeSet;
-use std::{cmp, fmt, ptr};
-use tracing::debug;
+use std::{fmt, ptr};
 
 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
 use imports::{Import, ImportKind, ImportResolver, NameResolution};
@@ -164,7 +162,6 @@ enum ImplTraitContext {
     Universal(LocalDefId),
 }
 
-#[derive(Eq)]
 struct BindingError {
     name: Symbol,
     origin: BTreeSet<Span>,
@@ -172,24 +169,6 @@ struct BindingError {
     could_be_path: bool,
 }
 
-impl PartialOrd for BindingError {
-    fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-impl PartialEq for BindingError {
-    fn eq(&self, other: &BindingError) -> bool {
-        self.name == other.name
-    }
-}
-
-impl Ord for BindingError {
-    fn cmp(&self, other: &BindingError) -> cmp::Ordering {
-        self.name.cmp(&other.name)
-    }
-}
-
 enum ResolutionError<'a> {
     /// Error E0401: can't use type or const parameters from outer function.
     GenericParamsFromOuterFunction(Res, HasGenericParams),
@@ -649,7 +628,7 @@ pub struct NameBinding<'a> {
     ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
     expansion: LocalExpnId,
     span: Span,
-    vis: ty::Visibility,
+    vis: ty::Visibility<DefId>,
 }
 
 pub trait ToNameBinding<'a> {
@@ -846,7 +825,7 @@ impl<'a> NameBinding<'a> {
     }
 }
 
-#[derive(Debug, Default, Clone)]
+#[derive(Default, Clone)]
 pub struct ExternPreludeEntry<'a> {
     extern_crate_item: Option<&'a NameBinding<'a>>,
     pub introduced_by_item: bool,
@@ -912,11 +891,6 @@ pub struct Resolver<'a> {
     label_res_map: NodeMap<NodeId>,
     /// Resolutions for lifetimes.
     lifetimes_res_map: NodeMap<LifetimeRes>,
-    /// Mapping from generics `def_id`s to TAIT generics `def_id`s.
-    /// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
-    /// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
-    /// field from the original parameter 'a to the new parameter 'a1.
-    generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
     /// Lifetime parameters that lowering will have to introduce.
     extra_lifetime_params_map: NodeMap<Vec<(Ident, NodeId, LifetimeRes)>>,
 
@@ -1018,7 +992,7 @@ pub struct Resolver<'a> {
     /// Table for mapping struct IDs into struct constructor IDs,
     /// it's not used during normal resolution, only for better error reporting.
     /// Also includes of list of each fields visibility
-    struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
+    struct_constructors: DefIdMap<(Res, ty::Visibility<DefId>, Vec<ty::Visibility<DefId>>)>,
 
     /// Features enabled for this crate.
     active_features: FxHashSet<Symbol>,
@@ -1279,7 +1253,6 @@ impl<'a> Resolver<'a> {
             import_res_map: Default::default(),
             label_res_map: Default::default(),
             lifetimes_res_map: Default::default(),
-            generics_def_id_map: Vec::new(),
             extra_lifetime_params_map: Default::default(),
             extern_crate_map: Default::default(),
             reexport_map: FxHashMap::default(),
@@ -1446,7 +1419,6 @@ impl<'a> Resolver<'a> {
             import_res_map: self.import_res_map,
             label_res_map: self.label_res_map,
             lifetimes_res_map: self.lifetimes_res_map,
-            generics_def_id_map: self.generics_def_id_map,
             extra_lifetime_params_map: self.extra_lifetime_params_map,
             next_node_id: self.next_node_id,
             node_id_to_def_id: self.node_id_to_def_id,
@@ -1491,7 +1463,6 @@ impl<'a> Resolver<'a> {
             import_res_map: self.import_res_map.clone(),
             label_res_map: self.label_res_map.clone(),
             lifetimes_res_map: self.lifetimes_res_map.clone(),
-            generics_def_id_map: self.generics_def_id_map.clone(),
             extra_lifetime_params_map: self.extra_lifetime_params_map.clone(),
             next_node_id: self.next_node_id.clone(),
             node_id_to_def_id: self.node_id_to_def_id.clone(),
@@ -1817,7 +1788,11 @@ impl<'a> Resolver<'a> {
         self.pat_span_map.insert(node, span);
     }
 
-    fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
+    fn is_accessible_from(
+        &self,
+        vis: ty::Visibility<impl Into<DefId>>,
+        module: Module<'a>,
+    ) -> bool {
         vis.is_accessible_from(module.nearest_parent_mod(), self)
     }
 
@@ -1871,10 +1846,8 @@ impl<'a> Resolver<'a> {
                     self.crate_loader.maybe_process_path_extern(ident.name)?
                 };
                 let crate_root = self.expect_module(crate_id.as_def_id());
-                Some(
-                    (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
-                        .to_name_binding(self.arenas),
-                )
+                let vis = ty::Visibility::<LocalDefId>::Public;
+                Some((crate_root, vis, DUMMY_SP, LocalExpnId::ROOT).to_name_binding(self.arenas))
             }
         })
     }
@@ -1991,7 +1964,7 @@ impl<'a> Resolver<'a> {
                         _ => panic!("invalid arg index"),
                     }
                 }
-                // Cache the lookup to avoid parsing attributes for an iterm multiple times.
+                // Cache the lookup to avoid parsing attributes for an item multiple times.
                 self.legacy_const_generic_args.insert(def_id, Some(ret.clone()));
                 return Some(ret);
             }
@@ -2021,6 +1994,24 @@ impl<'a> Resolver<'a> {
         }
         self.main_def = Some(MainDefinition { res, is_import, span });
     }
+
+    // Items that go to reexport table encoded to metadata and visible through it to other crates.
+    fn is_reexport(&self, binding: &NameBinding<'a>) -> Option<def::Res<!>> {
+        // FIXME: Consider changing the binding inserted by `#[macro_export] macro_rules`
+        // into the crate root to actual `NameBindingKind::Import`.
+        if binding.is_import()
+            || matches!(binding.kind, NameBindingKind::Res(_, _is_macro_export @ true))
+        {
+            let res = binding.res().expect_non_local();
+            // Ambiguous imports are treated as errors at this point and are
+            // not exposed to other crates (see #36837 for more details).
+            if res != def::Res::Err && !binding.is_ambiguity() {
+                return Some(res);
+            }
+        }
+
+        return None;
+    }
 }
 
 fn names_to_string(names: &[Symbol]) -> String {
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 0c428aa6cc05..dafa10e9e002 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -441,7 +441,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
                 }
                 PathResult::Indeterminate => indeterminate = true,
                 // We can only be sure that a path doesn't exist after having tested all the
-                // posibilities, only at that time we can return false.
+                // possibilities, only at that time we can return false.
                 PathResult::Failed { .. } => {}
                 PathResult::Module(_) => panic!("unexpected path resolution"),
             }
diff --git a/compiler/rustc_save_analysis/src/dump_visitor.rs b/compiler/rustc_save_analysis/src/dump_visitor.rs
index e2e0e1f5b300..adbc119387db 100644
--- a/compiler/rustc_save_analysis/src/dump_visitor.rs
+++ b/compiler/rustc_save_analysis/src/dump_visitor.rs
@@ -44,8 +44,6 @@ use rls_data::{
     RefKind, Relation, RelationKind, SpanData,
 };
 
-use tracing::{debug, error};
-
 #[rustfmt::skip] // https://github.com/rust-lang/rustfmt/issues/5213
 macro_rules! down_cast_data {
     ($id:ident, $kind:ident, $sp:expr) => {
@@ -347,14 +345,14 @@ impl<'tcx> DumpVisitor<'tcx> {
         body: hir::BodyId,
     ) {
         let map = self.tcx.hir();
-        self.nest_typeck_results(item.def_id, |v| {
+        self.nest_typeck_results(item.def_id.def_id, |v| {
             let body = map.body(body);
             if let Some(fn_data) = v.save_ctxt.get_item_data(item) {
                 down_cast_data!(fn_data, DefData, item.span);
                 v.process_formals(body.params, &fn_data.qualname);
                 v.process_generic_params(ty_params, &fn_data.qualname, item.hir_id());
 
-                v.dumper.dump_def(&access_from!(v.save_ctxt, item.def_id), fn_data);
+                v.dumper.dump_def(&access_from!(v.save_ctxt, item.def_id.def_id), fn_data);
             }
 
             for arg in decl.inputs {
@@ -375,10 +373,10 @@ impl<'tcx> DumpVisitor<'tcx> {
         typ: &'tcx hir::Ty<'tcx>,
         expr: &'tcx hir::Expr<'tcx>,
     ) {
-        self.nest_typeck_results(item.def_id, |v| {
+        self.nest_typeck_results(item.def_id.def_id, |v| {
             if let Some(var_data) = v.save_ctxt.get_item_data(item) {
                 down_cast_data!(var_data, DefData, item.span);
-                v.dumper.dump_def(&access_from!(v.save_ctxt, item.def_id), var_data);
+                v.dumper.dump_def(&access_from!(v.save_ctxt, item.def_id.def_id), var_data);
             }
             v.visit_ty(&typ);
             v.visit_expr(expr);
@@ -475,7 +473,7 @@ impl<'tcx> DumpVisitor<'tcx> {
             let span = self.span_from_span(item.ident.span);
             let attrs = self.tcx.hir().attrs(item.hir_id());
             self.dumper.dump_def(
-                &access_from!(self.save_ctxt, item.def_id),
+                &access_from!(self.save_ctxt, item.def_id.def_id),
                 Def {
                     kind,
                     id: id_from_def_id(item.def_id.to_def_id()),
@@ -493,7 +491,7 @@ impl<'tcx> DumpVisitor<'tcx> {
             );
         }
 
-        self.nest_typeck_results(item.def_id, |v| {
+        self.nest_typeck_results(item.def_id.def_id, |v| {
             for field in def.fields() {
                 v.process_struct_field_def(field, item.hir_id());
                 v.visit_ty(&field.ty);
@@ -515,7 +513,7 @@ impl<'tcx> DumpVisitor<'tcx> {
         };
         down_cast_data!(enum_data, DefData, item.span);
 
-        let access = access_from!(self.save_ctxt, item.def_id);
+        let access = access_from!(self.save_ctxt, item.def_id.def_id);
 
         for variant in enum_definition.variants {
             let name = variant.ident.name.to_string();
@@ -614,7 +612,7 @@ impl<'tcx> DumpVisitor<'tcx> {
         }
 
         let map = self.tcx.hir();
-        self.nest_typeck_results(item.def_id, |v| {
+        self.nest_typeck_results(item.def_id.def_id, |v| {
             v.visit_ty(&impl_.self_ty);
             if let Some(trait_ref) = &impl_.of_trait {
                 v.process_path(trait_ref.hir_ref_id, &hir::QPath::Resolved(None, &trait_ref.path));
@@ -650,7 +648,7 @@ impl<'tcx> DumpVisitor<'tcx> {
                 methods.iter().map(|i| id_from_def_id(i.id.def_id.to_def_id())).collect();
             let attrs = self.tcx.hir().attrs(item.hir_id());
             self.dumper.dump_def(
-                &access_from!(self.save_ctxt, item.def_id),
+                &access_from!(self.save_ctxt, item.def_id.def_id),
                 Def {
                     kind: DefKind::Trait,
                     id,
@@ -712,7 +710,7 @@ impl<'tcx> DumpVisitor<'tcx> {
     fn process_mod(&mut self, item: &'tcx hir::Item<'tcx>) {
         if let Some(mod_data) = self.save_ctxt.get_item_data(item) {
             down_cast_data!(mod_data, DefData, item.span);
-            self.dumper.dump_def(&access_from!(self.save_ctxt, item.def_id), mod_data);
+            self.dumper.dump_def(&access_from!(self.save_ctxt, item.def_id.def_id), mod_data);
         }
     }
 
@@ -805,6 +803,7 @@ impl<'tcx> DumpVisitor<'tcx> {
         &mut self,
         ex: &'tcx hir::Expr<'tcx>,
         seg: &'tcx hir::PathSegment<'tcx>,
+        receiver: &'tcx hir::Expr<'tcx>,
         args: &'tcx [hir::Expr<'tcx>],
     ) {
         debug!("process_method_call {:?} {:?}", ex, ex.span);
@@ -825,6 +824,7 @@ impl<'tcx> DumpVisitor<'tcx> {
         }
 
         // walk receiver and args
+        self.visit_expr(receiver);
         walk_list!(self, visit_expr, args);
     }
 
@@ -914,7 +914,10 @@ impl<'tcx> DumpVisitor<'tcx> {
                     _,
                 )
                 | Res::SelfTy { .. } => {
-                    self.dump_path_segment_ref(id, &hir::PathSegment::from_ident(ident));
+                    self.dump_path_segment_ref(
+                        id,
+                        &hir::PathSegment::new(ident, hir::HirId::INVALID, Res::Err),
+                    );
                 }
                 def => {
                     error!("unexpected definition kind when processing collected idents: {:?}", def)
@@ -974,10 +977,10 @@ impl<'tcx> DumpVisitor<'tcx> {
         self.process_macro_use(trait_item.span);
         match trait_item.kind {
             hir::TraitItemKind::Const(ref ty, body) => {
-                let body = body.map(|b| &self.tcx.hir().body(b).value);
+                let body = body.map(|b| self.tcx.hir().body(b).value);
                 let attrs = self.tcx.hir().attrs(trait_item.hir_id());
                 self.process_assoc_const(
-                    trait_item.def_id,
+                    trait_item.def_id.def_id,
                     trait_item.ident,
                     &ty,
                     body,
@@ -991,7 +994,7 @@ impl<'tcx> DumpVisitor<'tcx> {
                 self.process_method(
                     sig,
                     body,
-                    trait_item.def_id,
+                    trait_item.def_id.def_id,
                     trait_item.ident,
                     &trait_item.generics,
                     trait_item.span,
@@ -1047,7 +1050,7 @@ impl<'tcx> DumpVisitor<'tcx> {
                 let body = self.tcx.hir().body(body);
                 let attrs = self.tcx.hir().attrs(impl_item.hir_id());
                 self.process_assoc_const(
-                    impl_item.def_id,
+                    impl_item.def_id.def_id,
                     impl_item.ident,
                     &ty,
                     Some(&body.value),
@@ -1059,7 +1062,7 @@ impl<'tcx> DumpVisitor<'tcx> {
                 self.process_method(
                     sig,
                     Some(body),
-                    impl_item.def_id,
+                    impl_item.def_id.def_id,
                     impl_item.ident,
                     &impl_item.generics,
                     impl_item.span,
@@ -1133,10 +1136,10 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
             hir::ItemKind::Use(path, hir::UseKind::Single) => {
                 let sub_span = path.segments.last().unwrap().ident.span;
                 if !self.span.filter_generated(sub_span) {
-                    let access = access_from!(self.save_ctxt, item.def_id);
+                    let access = access_from!(self.save_ctxt, item.def_id.def_id);
                     let ref_id = self.lookup_def_id(item.hir_id()).map(id_from_def_id);
                     let span = self.span_from_span(sub_span);
-                    let parent = self.save_ctxt.tcx.local_parent(item.def_id);
+                    let parent = self.save_ctxt.tcx.local_parent(item.def_id.def_id);
                     self.dumper.import(
                         &access,
                         Import {
@@ -1154,16 +1157,16 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
             }
             hir::ItemKind::Use(path, hir::UseKind::Glob) => {
                 // Make a comma-separated list of names of imported modules.
-                let names = self.tcx.names_imported_by_glob_use(item.def_id);
+                let names = self.tcx.names_imported_by_glob_use(item.def_id.def_id);
                 let names: Vec<_> = names.iter().map(|n| n.to_string()).collect();
 
                 // Otherwise it's a span with wrong macro expansion info, which
                 // we don't want to track anyway, since it's probably macro-internal `use`
                 if let Some(sub_span) = self.span.sub_span_of_star(item.span) {
                     if !self.span.filter_generated(item.span) {
-                        let access = access_from!(self.save_ctxt, item.def_id);
+                        let access = access_from!(self.save_ctxt, item.def_id.def_id);
                         let span = self.span_from_span(sub_span);
-                        let parent = self.save_ctxt.tcx.local_parent(item.def_id);
+                        let parent = self.save_ctxt.tcx.local_parent(item.def_id.def_id);
                         self.dumper.import(
                             &access,
                             Import {
@@ -1184,7 +1187,7 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
                 let name_span = item.ident.span;
                 if !self.span.filter_generated(name_span) {
                     let span = self.span_from_span(name_span);
-                    let parent = self.save_ctxt.tcx.local_parent(item.def_id);
+                    let parent = self.save_ctxt.tcx.local_parent(item.def_id.def_id);
                     self.dumper.import(
                         &Access { public: false, reachable: false },
                         Import {
@@ -1232,7 +1235,7 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
                     let attrs = self.tcx.hir().attrs(item.hir_id());
 
                     self.dumper.dump_def(
-                        &access_from!(self.save_ctxt, item.def_id),
+                        &access_from!(self.save_ctxt, item.def_id.def_id),
                         Def {
                             kind: DefKind::Type,
                             id,
@@ -1303,7 +1306,7 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
                 if let hir::QPath::Resolved(_, path) = path {
                     self.write_sub_paths_truncated(path);
                 }
-                intravisit::walk_qpath(self, path, t.hir_id, t.span);
+                intravisit::walk_qpath(self, path, t.hir_id);
             }
             hir::TyKind::Array(ref ty, ref length) => {
                 self.visit_ty(ty);
@@ -1318,9 +1321,9 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
                         }),
                 }
             }
-            hir::TyKind::OpaqueDef(item_id, _) => {
+            hir::TyKind::OpaqueDef(item_id, _, _) => {
                 let item = self.tcx.hir().item(item_id);
-                self.nest_typeck_results(item_id.def_id, |v| v.visit_item(item));
+                self.nest_typeck_results(item_id.def_id.def_id, |v| v.visit_item(item));
             }
             _ => intravisit::walk_ty(self, t),
         }
@@ -1342,7 +1345,9 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
                 let res = self.save_ctxt.get_path_res(hir_expr.hir_id);
                 self.process_struct_lit(ex, path, fields, adt.variant_of_res(res), *rest)
             }
-            hir::ExprKind::MethodCall(ref seg, args, _) => self.process_method_call(ex, seg, args),
+            hir::ExprKind::MethodCall(ref seg, receiver, args, _) => {
+                self.process_method_call(ex, seg, receiver, args)
+            }
             hir::ExprKind::Field(ref sub_ex, _) => {
                 self.visit_expr(&sub_ex);
 
@@ -1425,7 +1430,7 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
     }
 
     fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem<'tcx>) {
-        let access = access_from!(self.save_ctxt, item.def_id);
+        let access = access_from!(self.save_ctxt, item.def_id.def_id);
 
         match item.kind {
             hir::ForeignItemKind::Fn(decl, _, ref generics) => {
diff --git a/compiler/rustc_save_analysis/src/errors.rs b/compiler/rustc_save_analysis/src/errors.rs
index f0ce41d02a6f..8a15ba63661b 100644
--- a/compiler/rustc_save_analysis/src/errors.rs
+++ b/compiler/rustc_save_analysis/src/errors.rs
@@ -1,8 +1,8 @@
-use rustc_macros::SessionDiagnostic;
+use rustc_macros::Diagnostic;
 
 use std::path::Path;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(save_analysis::could_not_open)]
 pub(crate) struct CouldNotOpen<'a> {
     pub file_name: &'a Path,
diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
index 619e083d89ad..ad7aca3cb949 100644
--- a/compiler/rustc_save_analysis/src/lib.rs
+++ b/compiler/rustc_save_analysis/src/lib.rs
@@ -1,12 +1,14 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(if_let_guard)]
-#![feature(let_else)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![feature(never_type)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
+#[macro_use]
+extern crate tracing;
+
 mod dump_visitor;
 mod dumper;
 #[macro_use]
@@ -49,8 +51,6 @@ use rls_data::{
     RefKind, Relation, RelationKind, SpanData,
 };
 
-use tracing::{debug, error, info};
-
 pub struct SaveContext<'tcx> {
     tcx: TyCtxt<'tcx>,
     maybe_typeck_results: Option<&'tcx ty::TypeckResults<'tcx>>,
@@ -595,13 +595,14 @@ impl<'tcx> SaveContext<'tcx> {
             Node::TraitRef(tr) => tr.path.res,
 
             Node::Item(&hir::Item { kind: hir::ItemKind::Use(path, _), .. }) => path.res,
-            Node::PathSegment(seg) => match seg.res {
-                Some(res) if res != Res::Err => res,
-                _ => {
+            Node::PathSegment(seg) => {
+                if seg.res != Res::Err {
+                    seg.res
+                } else {
                     let parent_node = self.tcx.hir().get_parent_node(hir_id);
                     self.get_path_res(parent_node)
                 }
-            },
+            }
 
             Node::Expr(&hir::Expr { kind: hir::ExprKind::Struct(ref qpath, ..), .. }) => {
                 self.typeck_results().qpath_res(qpath, hir_id)
@@ -620,7 +621,7 @@ impl<'tcx> SaveContext<'tcx> {
                 hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => {
                     // #75962: `self.typeck_results` may be different from the `hir_id`'s result.
                     if self.tcx.has_typeck_results(hir_id.owner.to_def_id()) {
-                        self.tcx.typeck(hir_id.owner).qpath_res(qpath, hir_id)
+                        self.tcx.typeck(hir_id.owner.def_id).qpath_res(qpath, hir_id)
                     } else {
                         Res::Err
                     }
@@ -647,7 +648,7 @@ impl<'tcx> SaveContext<'tcx> {
     }
 
     pub fn get_path_segment_data(&self, path_seg: &hir::PathSegment<'_>) -> Option<Ref> {
-        self.get_path_segment_data_with_id(path_seg, path_seg.hir_id?)
+        self.get_path_segment_data_with_id(path_seg, path_seg.hir_id)
     }
 
     pub fn get_path_segment_data_with_id(
@@ -683,6 +684,7 @@ impl<'tcx> SaveContext<'tcx> {
                 | HirDefKind::AssocTy
                 | HirDefKind::Trait
                 | HirDefKind::OpaqueTy
+                | HirDefKind::ImplTraitPlaceholder
                 | HirDefKind::TyParam,
                 def_id,
             ) => Some(Ref { kind: RefKind::Type, span, ref_id: id_from_def_id(def_id) }),
@@ -864,23 +866,12 @@ impl<'l> Visitor<'l> for PathCollector<'l> {
             hir::PatKind::TupleStruct(ref path, ..) | hir::PatKind::Path(ref path) => {
                 self.collected_paths.push((p.hir_id, path));
             }
-            hir::PatKind::Binding(bm, _, ident, _) => {
+            hir::PatKind::Binding(hir::BindingAnnotation(_, mutbl), _, ident, _) => {
                 debug!(
                     "PathCollector, visit ident in pat {}: {:?} {:?}",
                     ident, p.span, ident.span
                 );
-                let immut = match bm {
-                    // Even if the ref is mut, you can't change the ref, only
-                    // the data pointed at, so showing the initialising expression
-                    // is still worthwhile.
-                    hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Ref => {
-                        hir::Mutability::Not
-                    }
-                    hir::BindingAnnotation::Mutable | hir::BindingAnnotation::RefMut => {
-                        hir::Mutability::Mut
-                    }
-                };
-                self.collected_idents.push((p.hir_id, ident, immut));
+                self.collected_idents.push((p.hir_id, ident, mutbl));
             }
             _ => {}
         }
@@ -1049,7 +1040,7 @@ fn id_from_hir_id(id: hir::HirId, scx: &SaveContext<'_>) -> rls_data::Id {
         // crate (very unlikely to actually happen).
         rls_data::Id {
             krate: LOCAL_CRATE.as_u32(),
-            index: id.owner.local_def_index.as_u32() | id.local_id.as_u32().reverse_bits(),
+            index: id.owner.def_id.local_def_index.as_u32() | id.local_id.as_u32().reverse_bits(),
         }
     })
 }
diff --git a/compiler/rustc_save_analysis/src/sig.rs b/compiler/rustc_save_analysis/src/sig.rs
index d1286c9b8b0d..bae1828cd182 100644
--- a/compiler/rustc_save_analysis/src/sig.rs
+++ b/compiler/rustc_save_analysis/src/sig.rs
@@ -316,7 +316,7 @@ impl<'hir> Sig for hir::Ty<'hir> {
                 let text = format!("[{}; {}]", nested_ty.text, expr);
                 Ok(replace_text(nested_ty, text))
             }
-            hir::TyKind::OpaqueDef(item_id, _) => {
+            hir::TyKind::OpaqueDef(item_id, _, _) => {
                 let item = scx.tcx.hir().item(item_id);
                 item.make(offset, Some(item_id.hir_id()), scx)
             }
@@ -561,7 +561,13 @@ impl<'hir> Sig for hir::Item<'hir> {
             hir::ItemKind::ForeignMod { .. } => Err("extern mod"),
             hir::ItemKind::GlobalAsm(_) => Err("global asm"),
             hir::ItemKind::ExternCrate(_) => Err("extern crate"),
-            hir::ItemKind::OpaqueTy(..) => Err("opaque type"),
+            hir::ItemKind::OpaqueTy(ref opaque) => {
+                if opaque.in_trait {
+                    Err("opaque type in trait")
+                } else {
+                    Err("opaque type")
+                }
+            }
             // FIXME should implement this (e.g., pub use).
             hir::ItemKind::Use(..) => Err("import"),
         }
diff --git a/compiler/rustc_serialize/Cargo.toml b/compiler/rustc_serialize/Cargo.toml
index dbc5c15195c8..3b0b3144f2cd 100644
--- a/compiler/rustc_serialize/Cargo.toml
+++ b/compiler/rustc_serialize/Cargo.toml
@@ -6,6 +6,7 @@ edition = "2021"
 [dependencies]
 indexmap = "1.9.1"
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
+thin-vec = "0.2.8"
 
 [dev-dependencies]
 rustc_macros = { path = "../rustc_macros" }
diff --git a/compiler/rustc_serialize/src/collection_impls.rs b/compiler/rustc_serialize/src/collection_impls.rs
index 5e53f0b104df..8f8c504117cc 100644
--- a/compiler/rustc_serialize/src/collection_impls.rs
+++ b/compiler/rustc_serialize/src/collection_impls.rs
@@ -1,13 +1,12 @@
 //! Implementations of serialization for structures found in liballoc
 
-use std::hash::{BuildHasher, Hash};
-
 use crate::{Decodable, Decoder, Encodable, Encoder};
+use smallvec::{Array, SmallVec};
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, LinkedList, VecDeque};
+use std::hash::{BuildHasher, Hash};
 use std::rc::Rc;
 use std::sync::Arc;
-
-use smallvec::{Array, SmallVec};
+use thin_vec::ThinVec;
 
 impl<S: Encoder, A: Array<Item: Encodable<S>>> Encodable<S> for SmallVec<A> {
     fn encode(&self, s: &mut S) {
@@ -23,6 +22,19 @@ impl<D: Decoder, A: Array<Item: Decodable<D>>> Decodable<D> for SmallVec<A> {
     }
 }
 
+impl<S: Encoder, T: Encodable<S>> Encodable<S> for ThinVec<T> {
+    fn encode(&self, s: &mut S) {
+        self.as_slice().encode(s);
+    }
+}
+
+impl<D: Decoder, T: Decodable<D>> Decodable<D> for ThinVec<T> {
+    fn decode(d: &mut D) -> ThinVec<T> {
+        let len = d.read_usize();
+        (0..len).map(|_| Decodable::decode(d)).collect()
+    }
+}
+
 impl<S: Encoder, T: Encodable<S>> Encodable<S> for LinkedList<T> {
     fn encode(&self, s: &mut S) {
         s.emit_usize(self.len());
diff --git a/compiler/rustc_serialize/src/lib.rs b/compiler/rustc_serialize/src/lib.rs
index 91f4cfaf5aca..1f8d2336c4e5 100644
--- a/compiler/rustc_serialize/src/lib.rs
+++ b/compiler/rustc_serialize/src/lib.rs
@@ -14,7 +14,6 @@ Core encoding and decoding interfaces.
 #![feature(min_specialization)]
 #![feature(core_intrinsics)]
 #![feature(maybe_uninit_slice)]
-#![feature(let_else)]
 #![feature(new_uninit)]
 #![feature(allocator_api)]
 #![cfg_attr(test, feature(test))]
diff --git a/compiler/rustc_serialize/src/opaque.rs b/compiler/rustc_serialize/src/opaque.rs
index 5c17ef6ace2d..f35cc08f4fbf 100644
--- a/compiler/rustc_serialize/src/opaque.rs
+++ b/compiler/rustc_serialize/src/opaque.rs
@@ -193,7 +193,9 @@ impl FileEncoder {
         // shaves an instruction off those code paths (on x86 at least).
         assert!(capacity <= usize::MAX - max_leb128_len());
 
-        let file = File::create(path)?;
+        // Create the file for reading and writing, because some encoders do both
+        // (e.g. the metadata encoder when -Zmeta-stats is enabled)
+        let file = File::options().read(true).write(true).create(true).truncate(true).open(path)?;
 
         Ok(FileEncoder {
             buf: Box::new_uninit_slice(capacity),
diff --git a/compiler/rustc_session/src/cgu_reuse_tracker.rs b/compiler/rustc_session/src/cgu_reuse_tracker.rs
index 2a4a772f6108..2336d99363fd 100644
--- a/compiler/rustc_session/src/cgu_reuse_tracker.rs
+++ b/compiler/rustc_session/src/cgu_reuse_tracker.rs
@@ -10,7 +10,6 @@ use rustc_span::{Span, Symbol};
 use std::borrow::Cow;
 use std::fmt::{self};
 use std::sync::{Arc, Mutex};
-use tracing::debug;
 
 #[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
 pub enum CguReuse {
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 162fc9aa0a6e..70b470f3811d 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -3,6 +3,7 @@
 
 pub use crate::options::*;
 
+use crate::errors::TargetDataLayoutErrorsWrapper;
 use crate::search_paths::SearchPath;
 use crate::utils::{CanonicalizedPath, NativeLib, NativeLibKind};
 use crate::{early_error, early_warn, Session};
@@ -12,8 +13,8 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 
 use rustc_data_structures::stable_hasher::ToStableHashKey;
 use rustc_target::abi::{Align, TargetDataLayout};
-use rustc_target::spec::{LinkerFlavor, SplitDebuginfo, Target, TargetTriple, TargetWarnings};
-use rustc_target::spec::{PanicStrategy, SanitizerSet, TARGETS};
+use rustc_target::spec::{PanicStrategy, SanitizerSet, SplitDebuginfo};
+use rustc_target::spec::{Target, TargetTriple, TargetWarnings, TARGETS};
 
 use crate::parse::{CrateCheckConfig, CrateConfig};
 use rustc_feature::UnstableFeatures;
@@ -36,6 +37,8 @@ use std::iter::{self, FromIterator};
 use std::path::{Path, PathBuf};
 use std::str::{self, FromStr};
 
+pub mod sigpipe;
+
 /// The different settings that the `-C strip` flag can have.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum Strip {
@@ -535,6 +538,7 @@ pub enum PrintRequest {
     TargetLibdir,
     CrateName,
     Cfg,
+    CallingConventions,
     TargetList,
     TargetCPUs,
     TargetFeatures,
@@ -798,7 +802,15 @@ impl UnstableOptions {
 // The type of entry function, so users can have their own entry functions
 #[derive(Copy, Clone, PartialEq, Hash, Debug, HashStable_Generic)]
 pub enum EntryFnType {
-    Main,
+    Main {
+        /// Specifies what to do with `SIGPIPE` before calling `fn main()`.
+        ///
+        /// What values that are valid and what they mean must be in sync
+        /// across rustc and libstd, but we don't want it public in libstd,
+        /// so we take a bit of an unusual approach with simple constants
+        /// and an `include!()`.
+        sigpipe: u8,
+    },
     Start,
 }
 
@@ -888,10 +900,10 @@ fn default_configuration(sess: &Session) -> CrateConfig {
     let max_atomic_width = sess.target.max_atomic_width();
     let atomic_cas = sess.target.atomic_cas;
     let layout = TargetDataLayout::parse(&sess.target).unwrap_or_else(|err| {
-        sess.fatal(&err);
+        sess.emit_fatal(TargetDataLayoutErrorsWrapper(err));
     });
 
-    let mut ret = FxHashSet::default();
+    let mut ret = CrateConfig::default();
     ret.reserve(7); // the minimum number of insertions
     // Target bindings.
     ret.insert((sym::target_os, Some(Symbol::intern(os))));
@@ -1343,8 +1355,8 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
             "",
             "print",
             "Compiler information to print on stdout",
-            "[crate-name|file-names|sysroot|target-libdir|cfg|target-list|\
-             target-cpus|target-features|relocation-models|code-models|\
+            "[crate-name|file-names|sysroot|target-libdir|cfg|calling-conventions|\
+             target-list|target-cpus|target-features|relocation-models|code-models|\
              tls-models|target-spec-json|native-static-libs|stack-protector-strategies|\
              link-args]",
         ),
@@ -1783,6 +1795,7 @@ fn collect_print_requests(
         "sysroot" => PrintRequest::Sysroot,
         "target-libdir" => PrintRequest::TargetLibdir,
         "cfg" => PrintRequest::Cfg,
+        "calling-conventions" => PrintRequest::CallingConventions,
         "target-list" => PrintRequest::TargetList,
         "target-cpus" => PrintRequest::TargetCPUs,
         "target-features" => PrintRequest::TargetFeatures,
@@ -2379,16 +2392,6 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         }
     }
 
-    if cg.linker_flavor == Some(LinkerFlavor::L4Bender)
-        && !nightly_options::is_unstable_enabled(matches)
-    {
-        early_error(
-            error_format,
-            "`l4-bender` linker flavor is unstable, `-Z unstable-options` \
-             flag must also be passed to explicitly use it",
-        );
-    }
-
     let prints = collect_print_requests(&mut cg, &mut unstable_opts, matches, error_format);
 
     let cg = cg;
@@ -2530,7 +2533,7 @@ fn parse_pretty(unstable_opts: &UnstableOptions, efmt: ErrorOutputType) -> Optio
             ),
         ),
     };
-    tracing::debug!("got unpretty option: {first:?}");
+    debug!("got unpretty option: {first:?}");
     Some(first)
 }
 
diff --git a/compiler/rustc_session/src/config/sigpipe.rs b/compiler/rustc_session/src/config/sigpipe.rs
new file mode 100644
index 000000000000..a5c94118a47e
--- /dev/null
+++ b/compiler/rustc_session/src/config/sigpipe.rs
@@ -0,0 +1,22 @@
+//! NOTE: Keep these constants in sync with `library/std/src/sys/unix/mod.rs`!
+
+/// Do not touch `SIGPIPE`. Use whatever the parent process uses.
+#[allow(dead_code)]
+pub const INHERIT: u8 = 1;
+
+/// Change `SIGPIPE` to `SIG_IGN` so that failed writes results in `EPIPE`
+/// that are eventually converted to `ErrorKind::BrokenPipe`.
+#[allow(dead_code)]
+pub const SIG_IGN: u8 = 2;
+
+/// Change `SIGPIPE` to `SIG_DFL` so that the process is killed when trying
+/// to write to a closed pipe. This is usually the desired behavior for CLI
+/// apps that produce textual output that you want to pipe to other programs
+/// such as `head -n 1`.
+#[allow(dead_code)]
+pub const SIG_DFL: u8 = 3;
+
+/// `SIG_IGN` has been the Rust default since 2014. See
+/// <https://github.com/rust-lang/rust/issues/62569>.
+#[allow(dead_code)]
+pub const DEFAULT: u8 = SIG_IGN;
diff --git a/compiler/rustc_session/src/cstore.rs b/compiler/rustc_session/src/cstore.rs
index 11ef75bb2d4a..7d4a1e212a41 100644
--- a/compiler/rustc_session/src/cstore.rs
+++ b/compiler/rustc_session/src/cstore.rs
@@ -68,6 +68,8 @@ pub enum LinkagePreference {
 pub struct NativeLib {
     pub kind: NativeLibKind,
     pub name: Option<Symbol>,
+    /// If packed_bundled_libs enabled, actual filename of library is stored.
+    pub filename: Option<Symbol>,
     pub cfg: Option<ast::MetaItem>,
     pub foreign_module: Option<DefId>,
     pub wasm_import_module: Option<Symbol>,
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 7252f1799dac..e01dafe2102b 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -1,12 +1,15 @@
 use std::num::NonZeroU32;
 
-use crate as rustc_session;
 use crate::cgu_reuse_tracker::CguReuse;
-use rustc_errors::MultiSpan;
-use rustc_macros::SessionDiagnostic;
+use rustc_errors::{
+    fluent, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, MultiSpan,
+};
+use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
+use rustc_target::abi::TargetDataLayoutErrors;
+use rustc_target::spec::{SplitDebuginfo, StackProtector, TargetTriple};
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(session::incorrect_cgu_reuse_type)]
 pub struct IncorrectCguReuseType<'a> {
     #[primary_span]
@@ -17,14 +20,14 @@ pub struct IncorrectCguReuseType<'a> {
     pub at_least: u8,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(session::cgu_not_recorded)]
 pub struct CguNotRecorded<'a> {
     pub cgu_user_name: &'a str,
     pub cgu_name: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(session::feature_gate_error, code = "E0658")]
 pub struct FeatureGateError<'a> {
     #[primary_span]
@@ -32,14 +35,187 @@ pub struct FeatureGateError<'a> {
     pub explain: &'a str,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[note(session::feature_diagnostic_for_issue)]
 pub struct FeatureDiagnosticForIssue {
     pub n: NonZeroU32,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[help(session::feature_diagnostic_help)]
 pub struct FeatureDiagnosticHelp {
     pub feature: Symbol,
 }
+
+pub struct TargetDataLayoutErrorsWrapper<'a>(pub TargetDataLayoutErrors<'a>);
+
+impl IntoDiagnostic<'_, !> for TargetDataLayoutErrorsWrapper<'_> {
+    fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, !> {
+        let mut diag;
+        match self.0 {
+            TargetDataLayoutErrors::InvalidAddressSpace { addr_space, err, cause } => {
+                diag = handler.struct_fatal(fluent::session::target_invalid_address_space);
+                diag.set_arg("addr_space", addr_space);
+                diag.set_arg("cause", cause);
+                diag.set_arg("err", err);
+                diag
+            }
+            TargetDataLayoutErrors::InvalidBits { kind, bit, cause, err } => {
+                diag = handler.struct_fatal(fluent::session::target_invalid_bits);
+                diag.set_arg("kind", kind);
+                diag.set_arg("bit", bit);
+                diag.set_arg("cause", cause);
+                diag.set_arg("err", err);
+                diag
+            }
+            TargetDataLayoutErrors::MissingAlignment { cause } => {
+                diag = handler.struct_fatal(fluent::session::target_missing_alignment);
+                diag.set_arg("cause", cause);
+                diag
+            }
+            TargetDataLayoutErrors::InvalidAlignment { cause, err } => {
+                diag = handler.struct_fatal(fluent::session::target_invalid_alignment);
+                diag.set_arg("cause", cause);
+                diag.set_arg("err", err);
+                diag
+            }
+            TargetDataLayoutErrors::InconsistentTargetArchitecture { dl, target } => {
+                diag = handler.struct_fatal(fluent::session::target_inconsistent_architecture);
+                diag.set_arg("dl", dl);
+                diag.set_arg("target", target);
+                diag
+            }
+            TargetDataLayoutErrors::InconsistentTargetPointerWidth { pointer_size, target } => {
+                diag = handler.struct_fatal(fluent::session::target_inconsistent_pointer_width);
+                diag.set_arg("pointer_size", pointer_size);
+                diag.set_arg("target", target);
+                diag
+            }
+            TargetDataLayoutErrors::InvalidBitsSize { err } => {
+                diag = handler.struct_fatal(fluent::session::target_invalid_bits_size);
+                diag.set_arg("err", err);
+                diag
+            }
+        }
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(session::not_circumvent_feature)]
+pub struct NotCircumventFeature;
+
+#[derive(Diagnostic)]
+#[diag(session::linker_plugin_lto_windows_not_supported)]
+pub struct LinkerPluginToWindowsNotSupported;
+
+#[derive(Diagnostic)]
+#[diag(session::profile_use_file_does_not_exist)]
+pub struct ProfileUseFileDoesNotExist<'a> {
+    pub path: &'a std::path::Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::profile_sample_use_file_does_not_exist)]
+pub struct ProfileSampleUseFileDoesNotExist<'a> {
+    pub path: &'a std::path::Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::target_requires_unwind_tables)]
+pub struct TargetRequiresUnwindTables;
+
+#[derive(Diagnostic)]
+#[diag(session::sanitizer_not_supported)]
+pub struct SanitizerNotSupported {
+    pub us: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::sanitizers_not_supported)]
+pub struct SanitizersNotSupported {
+    pub us: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::cannot_mix_and_match_sanitizers)]
+pub struct CannotMixAndMatchSanitizers {
+    pub first: String,
+    pub second: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::cannot_enable_crt_static_linux)]
+pub struct CannotEnableCrtStaticLinux;
+
+#[derive(Diagnostic)]
+#[diag(session::sanitizer_cfi_enabled)]
+pub struct SanitizerCfiEnabled;
+
+#[derive(Diagnostic)]
+#[diag(session::unstable_virtual_function_elimination)]
+pub struct UnstableVirtualFunctionElimination;
+
+#[derive(Diagnostic)]
+#[diag(session::unsupported_dwarf_version)]
+pub struct UnsupportedDwarfVersion {
+    pub dwarf_version: u32,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::target_stack_protector_not_supported)]
+pub struct StackProtectorNotSupportedForTarget<'a> {
+    pub stack_protector: StackProtector,
+    pub target_triple: &'a TargetTriple,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::split_debuginfo_unstable_platform)]
+pub struct SplitDebugInfoUnstablePlatform {
+    pub debuginfo: SplitDebuginfo,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::file_is_not_writeable)]
+pub struct FileIsNotWriteable<'a> {
+    pub file: &'a std::path::Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::crate_name_does_not_match)]
+pub struct CrateNameDoesNotMatch<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub s: &'a str,
+    pub name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::crate_name_invalid)]
+pub struct CrateNameInvalid<'a> {
+    pub s: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(session::crate_name_empty)]
+pub struct CrateNameEmpty {
+    #[primary_span]
+    pub span: Option<Span>,
+}
+
+pub struct InvalidCharacterInCrateName<'a> {
+    pub span: Option<Span>,
+    pub character: char,
+    pub crate_name: &'a str,
+}
+
+impl IntoDiagnostic<'_> for InvalidCharacterInCrateName<'_> {
+    fn into_diagnostic(self, sess: &Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = sess.struct_err(fluent::session::invalid_character_in_create_name);
+        if let Some(sp) = self.span {
+            diag.set_span(sp);
+        }
+        diag.set_arg("character", self.character);
+        diag.set_arg("crate_name", self.crate_name);
+        diag
+    }
+}
diff --git a/compiler/rustc_session/src/filesearch.rs b/compiler/rustc_session/src/filesearch.rs
index c973e3140cef..e8edb38f5038 100644
--- a/compiler/rustc_session/src/filesearch.rs
+++ b/compiler/rustc_session/src/filesearch.rs
@@ -7,7 +7,6 @@ use std::path::{Path, PathBuf};
 
 use crate::search_paths::{PathKind, SearchPath};
 use rustc_fs_util::fix_windows_verbatim_for_gcc;
-use tracing::debug;
 
 #[derive(Copy, Clone)]
 pub enum FileMatch {
diff --git a/compiler/rustc_session/src/lib.rs b/compiler/rustc_session/src/lib.rs
index 429475c573c8..39e871f532c4 100644
--- a/compiler/rustc_session/src/lib.rs
+++ b/compiler/rustc_session/src/lib.rs
@@ -1,6 +1,5 @@
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(once_cell)]
@@ -9,11 +8,16 @@
 #![feature(map_many_mut)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 #[macro_use]
 extern crate rustc_macros;
 pub mod errors;
 
+#[macro_use]
+extern crate tracing;
+
 pub mod cgu_reuse_tracker;
 pub mod utils;
 pub use lint::{declare_lint, declare_lint_pass, declare_tool_lint, impl_lint_pass};
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 46bba02537dc..486c514a4f5c 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -5,7 +5,7 @@ use crate::lint;
 use crate::search_paths::SearchPath;
 use crate::utils::NativeLib;
 use rustc_errors::LanguageIdentifier;
-use rustc_target::spec::{CodeModel, LinkerFlavor, MergeFunctions, PanicStrategy, SanitizerSet};
+use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, SanitizerSet};
 use rustc_target::spec::{
     RelocModel, RelroLevel, SplitDebuginfo, StackProtector, TargetTriple, TlsModel,
 };
@@ -382,7 +382,7 @@ mod desc {
         "either a boolean (`yes`, `no`, `on`, `off`, etc), `checks`, or `nochecks`";
     pub const parse_cfprotection: &str = "`none`|`no`|`n` (default), `branch`, `return`, or `full`|`yes`|`y` (equivalent to `branch` and `return`)";
     pub const parse_strip: &str = "either `none`, `debuginfo`, or `symbols`";
-    pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavor::one_of();
+    pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavorCli::one_of();
     pub const parse_optimization_fuel: &str = "crate=integer";
     pub const parse_mir_spanview: &str = "`statement` (default), `terminator`, or `block`";
     pub const parse_instrument_coverage: &str =
@@ -763,8 +763,8 @@ mod parse {
         true
     }
 
-    pub(crate) fn parse_linker_flavor(slot: &mut Option<LinkerFlavor>, v: Option<&str>) -> bool {
-        match v.and_then(LinkerFlavor::from_str) {
+    pub(crate) fn parse_linker_flavor(slot: &mut Option<LinkerFlavorCli>, v: Option<&str>) -> bool {
+        match v.and_then(LinkerFlavorCli::from_str) {
             Some(lf) => *slot = Some(lf),
             _ => return false,
         }
@@ -1139,7 +1139,7 @@ options! {
         on C toolchain installed in the system"),
     linker: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
         "system linker to link outputs with"),
-    linker_flavor: Option<LinkerFlavor> = (None, parse_linker_flavor, [UNTRACKED],
+    linker_flavor: Option<LinkerFlavorCli> = (None, parse_linker_flavor, [UNTRACKED],
         "linker flavor"),
     linker_plugin_lto: LinkerPluginLto = (LinkerPluginLto::Disabled,
         parse_linker_plugin_lto, [TRACKED],
@@ -1345,6 +1345,8 @@ options! {
         "hash spans relative to their parent item for incr. comp. (default: no)"),
     incremental_verify_ich: bool = (false, parse_bool, [UNTRACKED],
         "verify incr. comp. hashes of green query instances (default: no)"),
+    inline_llvm: bool = (true, parse_bool, [TRACKED],
+        "enable LLVM inlining (default: yes)"),
     inline_mir: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "enable MIR inlining (default: no)"),
     inline_mir_threshold: Option<usize> = (None, parse_opt_number, [TRACKED],
@@ -1407,8 +1409,6 @@ options! {
         "the size at which the `large_assignments` lint starts to be emitted"),
     mutable_noalias: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "emit noalias metadata for mutable references (default: yes)"),
-    new_llvm_pass_manager: Option<bool> = (None, parse_opt_bool, [TRACKED],
-        "use new LLVM pass manager (default: no)"),
     nll_facts: bool = (false, parse_bool, [UNTRACKED],
         "dump facts from NLL analysis into side files (default: no)"),
     nll_facts_dir: String = ("nll-facts".to_string(), parse_string, [UNTRACKED],
@@ -1439,6 +1439,8 @@ options! {
         "pass `-install_name @rpath/...` to the macOS linker (default: no)"),
     diagnostic_width: Option<usize> = (None, parse_opt_number, [UNTRACKED],
         "set the current output width for diagnostic truncation"),
+    packed_bundled_libs: bool = (false, parse_bool, [TRACKED],
+        "change rlib format to store native libraries as archives"),
     panic_abort_tests: bool = (false, parse_bool, [TRACKED],
         "support compiling tests with panic=abort (default: no)"),
     panic_in_drop: PanicStrategy = (PanicStrategy::Unwind, parse_panic_strategy, [TRACKED],
diff --git a/compiler/rustc_session/src/output.rs b/compiler/rustc_session/src/output.rs
index e5e6579d75b1..2511bee46afe 100644
--- a/compiler/rustc_session/src/output.rs
+++ b/compiler/rustc_session/src/output.rs
@@ -1,5 +1,9 @@
 //! Related to out filenames of compilation (e.g. save analysis, binaries).
 use crate::config::{CrateType, Input, OutputFilenames, OutputType};
+use crate::errors::{
+    CrateNameDoesNotMatch, CrateNameEmpty, CrateNameInvalid, FileIsNotWriteable,
+    InvalidCharacterInCrateName,
+};
 use crate::Session;
 use rustc_ast as ast;
 use rustc_span::symbol::sym;
@@ -30,11 +34,7 @@ pub fn out_filename(
 /// read-only file.  We should be consistent.
 pub fn check_file_is_writeable(file: &Path, sess: &Session) {
     if !is_writeable(file) {
-        sess.fatal(&format!(
-            "output file {} is not writeable -- check its \
-                            permissions",
-            file.display()
-        ));
+        sess.emit_fatal(FileIsNotWriteable { file });
     }
 }
 
@@ -61,11 +61,7 @@ pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input)
     if let Some(ref s) = sess.opts.crate_name {
         if let Some((attr, name)) = attr_crate_name {
             if name.as_str() != s {
-                let msg = format!(
-                    "`--crate-name` and `#[crate_name]` are \
-                                   required to match, but `{s}` != `{name}`"
-                );
-                sess.span_err(attr.span, &msg);
+                sess.emit_err(CrateNameDoesNotMatch { span: attr.span, s, name });
             }
         }
         return validate(s.clone(), None);
@@ -77,11 +73,7 @@ pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input)
     if let Input::File(ref path) = *input {
         if let Some(s) = path.file_stem().and_then(|s| s.to_str()) {
             if s.starts_with('-') {
-                let msg = format!(
-                    "crate names cannot start with a `-`, but \
-                                   `{s}` has a leading hyphen"
-                );
-                sess.err(&msg);
+                sess.emit_err(CrateNameInvalid { s });
             } else {
                 return validate(s.replace('-', "_"), None);
             }
@@ -94,15 +86,9 @@ pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input)
 pub fn validate_crate_name(sess: &Session, s: &str, sp: Option<Span>) {
     let mut err_count = 0;
     {
-        let mut say = |s: &str| {
-            match sp {
-                Some(sp) => sess.span_err(sp, s),
-                None => sess.err(s),
-            };
-            err_count += 1;
-        };
         if s.is_empty() {
-            say("crate name must not be empty");
+            err_count += 1;
+            sess.emit_err(CrateNameEmpty { span: sp });
         }
         for c in s.chars() {
             if c.is_alphanumeric() {
@@ -111,7 +97,8 @@ pub fn validate_crate_name(sess: &Session, s: &str, sp: Option<Span>) {
             if c == '_' {
                 continue;
             }
-            say(&format!("invalid character `{c}` in crate name: `{s}`"));
+            err_count += 1;
+            sess.emit_err(InvalidCharacterInCrateName { span: sp, character: c, crate_name: s });
         }
     }
 
diff --git a/compiler/rustc_session/src/parse.rs b/compiler/rustc_session/src/parse.rs
index ebec754dcffb..b9202af2a676 100644
--- a/compiler/rustc_session/src/parse.rs
+++ b/compiler/rustc_session/src/parse.rs
@@ -6,14 +6,13 @@ use crate::errors::{FeatureDiagnosticForIssue, FeatureDiagnosticHelp, FeatureGat
 use crate::lint::{
     builtin::UNSTABLE_SYNTAX_PRE_EXPANSION, BufferedEarlyLint, BuiltinLintDiagnostics, Lint, LintId,
 };
-use crate::SessionDiagnostic;
 use rustc_ast::node_id::NodeId;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_data_structures::sync::{Lock, Lrc};
 use rustc_errors::{emitter::SilentEmitter, ColorConfig, Handler};
 use rustc_errors::{
     fallback_fluent_bundle, Applicability, Diagnostic, DiagnosticBuilder, DiagnosticId,
-    DiagnosticMessage, EmissionGuarantee, ErrorGuaranteed, MultiSpan, StashKey,
+    DiagnosticMessage, EmissionGuarantee, ErrorGuaranteed, IntoDiagnostic, MultiSpan, StashKey,
 };
 use rustc_feature::{find_feature_issue, GateIssue, UnstableFeatures};
 use rustc_span::edition::Edition;
@@ -21,11 +20,12 @@ use rustc_span::hygiene::ExpnId;
 use rustc_span::source_map::{FilePathMapping, SourceMap};
 use rustc_span::{Span, Symbol};
 
+use rustc_ast::attr::AttrIdGenerator;
 use std::str;
 
 /// The set of keys (and, optionally, values) that define the compilation
 /// environment of the crate, used to drive conditional compilation.
-pub type CrateConfig = FxHashSet<(Symbol, Option<Symbol>)>;
+pub type CrateConfig = FxIndexSet<(Symbol, Option<Symbol>)>;
 pub type CrateCheckConfig = CheckCfg<Symbol>;
 
 /// Collected spans during parsing for places where a certain feature was
@@ -219,6 +219,8 @@ pub struct ParseSess {
     /// Spans passed to `proc_macro::quote_span`. Each span has a numerical
     /// identifier represented by its position in the vector.
     pub proc_macro_quoted_spans: Lock<Vec<Span>>,
+    /// Used to generate new `AttrId`s. Every `AttrId` is unique.
+    pub attr_id_generator: AttrIdGenerator,
 }
 
 impl ParseSess {
@@ -241,7 +243,7 @@ impl ParseSess {
         Self {
             span_diagnostic: handler,
             unstable_features: UnstableFeatures::from_environment(None),
-            config: FxHashSet::default(),
+            config: FxIndexSet::default(),
             check_config: CrateCheckConfig::default(),
             edition: ExpnId::root().expn_data().edition,
             raw_identifier_spans: Lock::new(Vec::new()),
@@ -257,6 +259,7 @@ impl ParseSess {
             type_ascription_path_suggestions: Default::default(),
             assume_incomplete_release: false,
             proc_macro_quoted_spans: Default::default(),
+            attr_id_generator: AttrIdGenerator::new(),
         }
     }
 
@@ -341,34 +344,34 @@ impl ParseSess {
 
     pub fn create_err<'a>(
         &'a self,
-        err: impl SessionDiagnostic<'a>,
+        err: impl IntoDiagnostic<'a>,
     ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        err.into_diagnostic(self)
+        err.into_diagnostic(&self.span_diagnostic)
     }
 
-    pub fn emit_err<'a>(&'a self, err: impl SessionDiagnostic<'a>) -> ErrorGuaranteed {
+    pub fn emit_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> ErrorGuaranteed {
         self.create_err(err).emit()
     }
 
     pub fn create_warning<'a>(
         &'a self,
-        warning: impl SessionDiagnostic<'a, ()>,
+        warning: impl IntoDiagnostic<'a, ()>,
     ) -> DiagnosticBuilder<'a, ()> {
-        warning.into_diagnostic(self)
+        warning.into_diagnostic(&self.span_diagnostic)
     }
 
-    pub fn emit_warning<'a>(&'a self, warning: impl SessionDiagnostic<'a, ()>) {
+    pub fn emit_warning<'a>(&'a self, warning: impl IntoDiagnostic<'a, ()>) {
         self.create_warning(warning).emit()
     }
 
     pub fn create_fatal<'a>(
         &'a self,
-        fatal: impl SessionDiagnostic<'a, !>,
+        fatal: impl IntoDiagnostic<'a, !>,
     ) -> DiagnosticBuilder<'a, !> {
-        fatal.into_diagnostic(self)
+        fatal.into_diagnostic(&self.span_diagnostic)
     }
 
-    pub fn emit_fatal<'a>(&'a self, fatal: impl SessionDiagnostic<'a, !>) -> ! {
+    pub fn emit_fatal<'a>(&'a self, fatal: impl IntoDiagnostic<'a, !>) -> ! {
         self.create_fatal(fatal).emit()
     }
 
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index ec5e5170d359..0142e9817663 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -2,6 +2,13 @@ use crate::cgu_reuse_tracker::CguReuseTracker;
 use crate::code_stats::CodeStats;
 pub use crate::code_stats::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
 use crate::config::{self, CrateType, InstrumentCoverage, OptLevel, OutputType, SwitchWithOptPath};
+use crate::errors::{
+    CannotEnableCrtStaticLinux, CannotMixAndMatchSanitizers, LinkerPluginToWindowsNotSupported,
+    NotCircumventFeature, ProfileSampleUseFileDoesNotExist, ProfileUseFileDoesNotExist,
+    SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported,
+    SplitDebugInfoUnstablePlatform, StackProtectorNotSupportedForTarget,
+    TargetRequiresUnwindTables, UnstableVirtualFunctionElimination, UnsupportedDwarfVersion,
+};
 use crate::parse::{add_feature_diagnostics, ParseSess};
 use crate::search_paths::{PathKind, SearchPath};
 use crate::{filesearch, lint};
@@ -21,7 +28,7 @@ use rustc_errors::json::JsonEmitter;
 use rustc_errors::registry::Registry;
 use rustc_errors::{
     error_code, fallback_fluent_bundle, DiagnosticBuilder, DiagnosticId, DiagnosticMessage,
-    EmissionGuarantee, ErrorGuaranteed, FluentBundle, LazyFallbackBundle, MultiSpan,
+    ErrorGuaranteed, FluentBundle, IntoDiagnostic, LazyFallbackBundle, MultiSpan,
 };
 use rustc_macros::HashStable_Generic;
 pub use rustc_span::def_id::StableCrateId;
@@ -110,6 +117,12 @@ impl Mul<usize> for Limit {
     }
 }
 
+impl rustc_errors::IntoDiagnosticArg for Limit {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        self.to_string().into_diagnostic_arg()
+    }
+}
+
 #[derive(Clone, Copy, Debug, HashStable_Generic)]
 pub struct Limits {
     /// The maximum recursion limit for potentially infinitely recursive
@@ -210,15 +223,6 @@ pub struct PerfStats {
     pub normalize_projection_ty: AtomicUsize,
 }
 
-/// Trait implemented by error types. This should not be implemented manually. Instead, use
-/// `#[derive(SessionDiagnostic)]` -- see [rustc_macros::SessionDiagnostic].
-#[rustc_diagnostic_item = "SessionDiagnostic"]
-pub trait SessionDiagnostic<'a, T: EmissionGuarantee = ErrorGuaranteed> {
-    /// Write out as a diagnostic out of `sess`.
-    #[must_use]
-    fn into_diagnostic(self, sess: &'a ParseSess) -> DiagnosticBuilder<'a, T>;
-}
-
 impl Session {
     pub fn miri_unleashed_feature(&self, span: Span, feature_gate: Option<Symbol>) {
         self.miri_unleashed_features.lock().push((span, feature_gate));
@@ -229,6 +233,9 @@ impl Session {
         if !unleashed_features.is_empty() {
             let mut must_err = false;
             // Create a diagnostic pointing at where things got unleashed.
+            // FIXME(#100717): needs eager translation/lists
+            #[allow(rustc::untranslatable_diagnostic)]
+            #[allow(rustc::diagnostic_outside_of_impl)]
             let mut diag = self.struct_warn("skipping const checks");
             for &(span, feature_gate) in unleashed_features.iter() {
                 // FIXME: `span_label` doesn't do anything, so we use "help" as a hack.
@@ -244,10 +251,7 @@ impl Session {
             // If we should err, make sure we did.
             if must_err && self.has_errors().is_none() {
                 // We have skipped a feature gate, and not run into other errors... reject.
-                self.err(
-                    "`-Zunleash-the-miri-inside-of-you` may not be used to circumvent feature \
-                     gates, except when testing error paths in the CTFE engine",
-                );
+                self.emit_err(NotCircumventFeature);
             }
         }
     }
@@ -284,6 +288,8 @@ impl Session {
     }
 
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_warn<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -292,6 +298,8 @@ impl Session {
         self.diagnostic().struct_span_warn(sp, msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_warn_with_expectation<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -301,6 +309,8 @@ impl Session {
         self.diagnostic().struct_span_warn_with_expectation(sp, msg, id)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_warn_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -310,10 +320,14 @@ impl Session {
         self.diagnostic().struct_span_warn_with_code(sp, msg, code)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_warn(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
         self.diagnostic().struct_warn(msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_warn_with_expectation(
         &self,
         msg: impl Into<DiagnosticMessage>,
@@ -322,6 +336,8 @@ impl Session {
         self.diagnostic().struct_warn_with_expectation(msg, id)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_allow<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -330,10 +346,14 @@ impl Session {
         self.diagnostic().struct_span_allow(sp, msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_allow(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
         self.diagnostic().struct_allow(msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_expect(
         &self,
         msg: impl Into<DiagnosticMessage>,
@@ -342,6 +362,8 @@ impl Session {
         self.diagnostic().struct_expect(msg, id)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_err<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -350,6 +372,8 @@ impl Session {
         self.diagnostic().struct_span_err(sp, msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_err_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -360,6 +384,8 @@ impl Session {
     }
     // FIXME: This method should be removed (every error should have an associated error code).
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_err(
         &self,
         msg: impl Into<DiagnosticMessage>,
@@ -367,6 +393,8 @@ impl Session {
         self.parse_sess.struct_err(msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_err_with_code(
         &self,
         msg: impl Into<DiagnosticMessage>,
@@ -375,6 +403,8 @@ impl Session {
         self.diagnostic().struct_err_with_code(msg, code)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_warn_with_code(
         &self,
         msg: impl Into<DiagnosticMessage>,
@@ -383,6 +413,8 @@ impl Session {
         self.diagnostic().struct_warn_with_code(msg, code)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_fatal<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -391,6 +423,8 @@ impl Session {
         self.diagnostic().struct_span_fatal(sp, msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_span_fatal_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -400,15 +434,21 @@ impl Session {
         self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_fatal(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, !> {
         self.diagnostic().struct_fatal(msg)
     }
 
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: impl Into<DiagnosticMessage>) -> ! {
         self.diagnostic().span_fatal(sp, msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_fatal_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -418,10 +458,14 @@ impl Session {
         self.diagnostic().span_fatal_with_code(sp, msg, code)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn fatal(&self, msg: impl Into<DiagnosticMessage>) -> ! {
         self.diagnostic().fatal(msg).raise()
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_err_or_warn<S: Into<MultiSpan>>(
         &self,
         is_warning: bool,
@@ -435,6 +479,8 @@ impl Session {
         }
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_err<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -443,6 +489,8 @@ impl Session {
         self.diagnostic().span_err(sp, msg)
     }
     #[rustc_lint_diagnostics]
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_err_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -457,13 +505,13 @@ impl Session {
     }
     pub fn create_err<'a>(
         &'a self,
-        err: impl SessionDiagnostic<'a>,
+        err: impl IntoDiagnostic<'a>,
     ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         self.parse_sess.create_err(err)
     }
     pub fn create_feature_err<'a>(
         &'a self,
-        err: impl SessionDiagnostic<'a>,
+        err: impl IntoDiagnostic<'a>,
         feature: Symbol,
     ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         let mut err = self.parse_sess.create_err(err);
@@ -473,25 +521,25 @@ impl Session {
         add_feature_diagnostics(&mut err, &self.parse_sess, feature);
         err
     }
-    pub fn emit_err<'a>(&'a self, err: impl SessionDiagnostic<'a>) -> ErrorGuaranteed {
+    pub fn emit_err<'a>(&'a self, err: impl IntoDiagnostic<'a>) -> ErrorGuaranteed {
         self.parse_sess.emit_err(err)
     }
     pub fn create_warning<'a>(
         &'a self,
-        err: impl SessionDiagnostic<'a, ()>,
+        err: impl IntoDiagnostic<'a, ()>,
     ) -> DiagnosticBuilder<'a, ()> {
         self.parse_sess.create_warning(err)
     }
-    pub fn emit_warning<'a>(&'a self, warning: impl SessionDiagnostic<'a, ()>) {
+    pub fn emit_warning<'a>(&'a self, warning: impl IntoDiagnostic<'a, ()>) {
         self.parse_sess.emit_warning(warning)
     }
     pub fn create_fatal<'a>(
         &'a self,
-        fatal: impl SessionDiagnostic<'a, !>,
+        fatal: impl IntoDiagnostic<'a, !>,
     ) -> DiagnosticBuilder<'a, !> {
         self.parse_sess.create_fatal(fatal)
     }
-    pub fn emit_fatal<'a>(&'a self, fatal: impl SessionDiagnostic<'a, !>) -> ! {
+    pub fn emit_fatal<'a>(&'a self, fatal: impl IntoDiagnostic<'a, !>) -> ! {
         self.parse_sess.emit_fatal(fatal)
     }
     #[inline]
@@ -528,9 +576,13 @@ impl Session {
             Err(ErrorGuaranteed::unchecked_claim_error_was_emitted())
         }
     }
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: impl Into<DiagnosticMessage>) {
         self.diagnostic().span_warn(sp, msg)
     }
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn span_warn_with_code<S: Into<MultiSpan>>(
         &self,
         sp: S,
@@ -579,6 +631,8 @@ impl Session {
     ) {
         self.diagnostic().span_note_without_error(sp, msg)
     }
+    #[allow(rustc::untranslatable_diagnostic)]
+    #[allow(rustc::diagnostic_outside_of_impl)]
     pub fn struct_note_without_error(
         &self,
         msg: impl Into<DiagnosticMessage>,
@@ -1290,10 +1344,8 @@ pub fn build_session(
     let warnings_allow = sopts
         .lint_opts
         .iter()
-        .filter(|&&(ref key, _)| *key == "warnings")
-        .map(|&(_, ref level)| *level == lint::Allow)
-        .last()
-        .unwrap_or(false);
+        .rfind(|&&(ref key, _)| *key == "warnings")
+        .map_or(false, |&(_, level)| level == lint::Allow);
     let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
     let can_emit_warnings = !(warnings_allow || cap_lints_allow);
 
@@ -1463,40 +1515,28 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
         && sess.opts.cg.prefer_dynamic
         && sess.target.is_like_windows
     {
-        sess.err(
-            "Linker plugin based LTO is not supported together with \
-                  `-C prefer-dynamic` when targeting Windows-like targets",
-        );
+        sess.emit_err(LinkerPluginToWindowsNotSupported);
     }
 
     // Make sure that any given profiling data actually exists so LLVM can't
     // decide to silently skip PGO.
     if let Some(ref path) = sess.opts.cg.profile_use {
         if !path.exists() {
-            sess.err(&format!(
-                "File `{}` passed to `-C profile-use` does not exist.",
-                path.display()
-            ));
+            sess.emit_err(ProfileUseFileDoesNotExist { path });
         }
     }
 
     // Do the same for sample profile data.
     if let Some(ref path) = sess.opts.unstable_opts.profile_sample_use {
         if !path.exists() {
-            sess.err(&format!(
-                "File `{}` passed to `-C profile-sample-use` does not exist.",
-                path.display()
-            ));
+            sess.emit_err(ProfileSampleUseFileDoesNotExist { path });
         }
     }
 
     // Unwind tables cannot be disabled if the target requires them.
     if let Some(include_uwtables) = sess.opts.cg.force_unwind_tables {
         if sess.target.requires_uwtable && !include_uwtables {
-            sess.err(
-                "target requires unwind tables, they cannot be disabled with \
-                     `-C force-unwind-tables=no`.",
-            );
+            sess.emit_err(TargetRequiresUnwindTables);
         }
     }
 
@@ -1506,64 +1546,55 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
     match unsupported_sanitizers.into_iter().count() {
         0 => {}
         1 => {
-            sess.err(&format!(
-                "{} sanitizer is not supported for this target",
-                unsupported_sanitizers
-            ));
+            sess.emit_err(SanitizerNotSupported { us: unsupported_sanitizers.to_string() });
         }
         _ => {
-            sess.err(&format!(
-                "{} sanitizers are not supported for this target",
-                unsupported_sanitizers
-            ));
+            sess.emit_err(SanitizersNotSupported { us: unsupported_sanitizers.to_string() });
         }
     }
     // Cannot mix and match sanitizers.
     let mut sanitizer_iter = sess.opts.unstable_opts.sanitizer.into_iter();
     if let (Some(first), Some(second)) = (sanitizer_iter.next(), sanitizer_iter.next()) {
-        sess.err(&format!("`-Zsanitizer={first}` is incompatible with `-Zsanitizer={second}`"));
+        sess.emit_err(CannotMixAndMatchSanitizers {
+            first: first.to_string(),
+            second: second.to_string(),
+        });
     }
 
     // Cannot enable crt-static with sanitizers on Linux
     if sess.crt_static(None) && !sess.opts.unstable_opts.sanitizer.is_empty() {
-        sess.err(
-            "sanitizer is incompatible with statically linked libc, \
-                                disable it using `-C target-feature=-crt-static`",
-        );
+        sess.emit_err(CannotEnableCrtStaticLinux);
     }
 
     // LLVM CFI and VFE both require LTO.
     if sess.lto() != config::Lto::Fat {
         if sess.is_sanitizer_cfi_enabled() {
-            sess.err("`-Zsanitizer=cfi` requires `-Clto`");
+            sess.emit_err(SanitizerCfiEnabled);
         }
         if sess.opts.unstable_opts.virtual_function_elimination {
-            sess.err("`-Zvirtual-function-elimination` requires `-Clto`");
+            sess.emit_err(UnstableVirtualFunctionElimination);
         }
     }
 
     if sess.opts.unstable_opts.stack_protector != StackProtector::None {
         if !sess.target.options.supports_stack_protector {
-            sess.warn(&format!(
-                "`-Z stack-protector={}` is not supported for target {} and will be ignored",
-                sess.opts.unstable_opts.stack_protector, sess.opts.target_triple
-            ))
+            sess.emit_warning(StackProtectorNotSupportedForTarget {
+                stack_protector: sess.opts.unstable_opts.stack_protector,
+                target_triple: &sess.opts.target_triple,
+            });
         }
     }
 
     if let Some(dwarf_version) = sess.opts.unstable_opts.dwarf_version {
         if dwarf_version > 5 {
-            sess.err(&format!("requested DWARF version {} is greater than 5", dwarf_version));
+            sess.emit_err(UnsupportedDwarfVersion { dwarf_version });
         }
     }
 
     if !sess.target.options.supported_split_debuginfo.contains(&sess.split_debuginfo())
         && !sess.opts.unstable_opts.unstable_options
     {
-        sess.err(&format!(
-            "`-Csplit-debuginfo={}` is unstable on this platform",
-            sess.split_debuginfo()
-        ));
+        sess.emit_err(SplitDebugInfoUnstablePlatform { debuginfo: sess.split_debuginfo() });
     }
 }
 
@@ -1608,14 +1639,20 @@ fn early_error_handler(output: config::ErrorOutputType) -> rustc_errors::Handler
     rustc_errors::Handler::with_emitter(true, None, emitter)
 }
 
+#[allow(rustc::untranslatable_diagnostic)]
+#[allow(rustc::diagnostic_outside_of_impl)]
 pub fn early_error_no_abort(output: config::ErrorOutputType, msg: &str) -> ErrorGuaranteed {
     early_error_handler(output).struct_err(msg).emit()
 }
 
+#[allow(rustc::untranslatable_diagnostic)]
+#[allow(rustc::diagnostic_outside_of_impl)]
 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
     early_error_handler(output).struct_fatal(msg).emit()
 }
 
+#[allow(rustc::untranslatable_diagnostic)]
+#[allow(rustc::diagnostic_outside_of_impl)]
 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
     early_error_handler(output).struct_warn(msg).emit()
 }
diff --git a/compiler/rustc_smir/src/mir.rs b/compiler/rustc_smir/src/mir.rs
index 855605b1a4f9..887e65729306 100644
--- a/compiler/rustc_smir/src/mir.rs
+++ b/compiler/rustc_smir/src/mir.rs
@@ -1,10 +1,10 @@
+pub use crate::very_unstable::hir::ImplicitSelfKind;
 pub use crate::very_unstable::middle::mir::{
     visit::MutVisitor, AggregateKind, AssertKind, BasicBlock, BasicBlockData, BinOp, BindingForm,
     BlockTailInfo, Body, BorrowKind, CastKind, ClearCrossCrate, Constant, ConstantKind,
-    CopyNonOverlapping, Coverage, FakeReadCause, Field, GeneratorInfo, ImplicitSelfKind,
-    InlineAsmOperand, Local, LocalDecl, LocalInfo, LocalKind, Location, MirPhase, MirSource,
-    NullOp, Operand, Place, PlaceRef, ProjectionElem, ProjectionKind, Promoted, RetagKind, Rvalue,
-    Safety, SourceInfo, SourceScope, SourceScopeData, SourceScopeLocalData, Statement,
-    StatementKind, UnOp, UserTypeProjection, UserTypeProjections, VarBindingForm, VarDebugInfo,
-    VarDebugInfoContents,
+    CopyNonOverlapping, Coverage, FakeReadCause, Field, GeneratorInfo, InlineAsmOperand, Local,
+    LocalDecl, LocalInfo, LocalKind, Location, MirPhase, MirSource, NullOp, Operand, Place,
+    PlaceRef, ProjectionElem, ProjectionKind, Promoted, RetagKind, Rvalue, Safety, SourceInfo,
+    SourceScope, SourceScopeData, SourceScopeLocalData, Statement, StatementKind, UnOp,
+    UserTypeProjection, UserTypeProjections, VarBindingForm, VarDebugInfo, VarDebugInfoContents,
 };
diff --git a/compiler/rustc_span/src/def_id.rs b/compiler/rustc_span/src/def_id.rs
index a1533fe46b3e..37b8371a8fe2 100644
--- a/compiler/rustc_span/src/def_id.rs
+++ b/compiler/rustc_span/src/def_id.rs
@@ -305,6 +305,12 @@ impl DefId {
     }
 }
 
+impl From<LocalDefId> for DefId {
+    fn from(local: LocalDefId) -> DefId {
+        local.to_def_id()
+    }
+}
+
 impl<E: Encoder> Encodable<E> for DefId {
     default fn encode(&self, s: &mut E) {
         self.krate.encode(s);
@@ -331,7 +337,7 @@ impl fmt::Debug for DefId {
     }
 }
 
-rustc_data_structures::define_id_collections!(DefIdMap, DefIdSet, DefId);
+rustc_data_structures::define_id_collections!(DefIdMap, DefIdSet, DefIdMapEntry, DefId);
 
 /// A `LocalDefId` is equivalent to a `DefId` with `krate == LOCAL_CRATE`. Since
 /// we encode this information in the type, we can ensure at compile time that
@@ -393,7 +399,12 @@ impl<D: Decoder> Decodable<D> for LocalDefId {
     }
 }
 
-rustc_data_structures::define_id_collections!(LocalDefIdMap, LocalDefIdSet, LocalDefId);
+rustc_data_structures::define_id_collections!(
+    LocalDefIdMap,
+    LocalDefIdSet,
+    LocalDefIdMapEntry,
+    LocalDefId
+);
 
 impl<CTX: HashStableContext> HashStable<CTX> for DefId {
     #[inline]
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index e169d3c7cfb7..191186af6fa0 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -41,7 +41,6 @@ use rustc_macros::HashStable_Generic;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use std::fmt;
 use std::hash::Hash;
-use tracing::*;
 
 /// A `SyntaxContext` represents a chain of pairs `(ExpnId, Transparency)` named "marks".
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -945,12 +944,6 @@ pub struct ExpnData {
     /// internally without forcing the whole crate to opt-in
     /// to them.
     pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
-    /// Whether the macro is allowed to use `unsafe` internally
-    /// even if the user crate has `#![forbid(unsafe_code)]`.
-    pub allow_internal_unsafe: bool,
-    /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`)
-    /// for a given macro.
-    pub local_inner_macros: bool,
     /// Edition of the crate in which the macro is defined.
     pub edition: Edition,
     /// The `DefId` of the macro being invoked,
@@ -958,6 +951,13 @@ pub struct ExpnData {
     pub macro_def_id: Option<DefId>,
     /// The normal module (`mod`) in which the expanded macro was defined.
     pub parent_module: Option<DefId>,
+    /// Suppresses the `unsafe_code` lint for code produced by this macro.
+    pub allow_internal_unsafe: bool,
+    /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
+    pub local_inner_macros: bool,
+    /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
+    /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
+    pub collapse_debuginfo: bool,
 }
 
 impl !PartialEq for ExpnData {}
@@ -970,11 +970,12 @@ impl ExpnData {
         call_site: Span,
         def_site: Span,
         allow_internal_unstable: Option<Lrc<[Symbol]>>,
-        allow_internal_unsafe: bool,
-        local_inner_macros: bool,
         edition: Edition,
         macro_def_id: Option<DefId>,
         parent_module: Option<DefId>,
+        allow_internal_unsafe: bool,
+        local_inner_macros: bool,
+        collapse_debuginfo: bool,
     ) -> ExpnData {
         ExpnData {
             kind,
@@ -982,12 +983,13 @@ impl ExpnData {
             call_site,
             def_site,
             allow_internal_unstable,
-            allow_internal_unsafe,
-            local_inner_macros,
             edition,
             macro_def_id,
             parent_module,
             disambiguator: 0,
+            allow_internal_unsafe,
+            local_inner_macros,
+            collapse_debuginfo,
         }
     }
 
@@ -1005,12 +1007,13 @@ impl ExpnData {
             call_site,
             def_site: DUMMY_SP,
             allow_internal_unstable: None,
-            allow_internal_unsafe: false,
-            local_inner_macros: false,
             edition,
             macro_def_id,
             parent_module,
             disambiguator: 0,
+            allow_internal_unsafe: false,
+            local_inner_macros: false,
+            collapse_debuginfo: false,
         }
     }
 
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 860af7fe93a0..f8df41697159 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -15,7 +15,6 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
-#![feature(let_else)]
 #![feature(if_let_guard)]
 #![feature(negative_impls)]
 #![feature(min_specialization)]
@@ -76,8 +75,6 @@ use md5::Md5;
 use sha1::Sha1;
 use sha2::Sha256;
 
-use tracing::debug;
-
 #[cfg(test)]
 mod tests;
 
@@ -535,9 +532,6 @@ impl Span {
         self.data().with_hi(hi)
     }
     #[inline]
-    pub fn ctxt(self) -> SyntaxContext {
-        self.data_untracked().ctxt
-    }
     pub fn eq_ctxt(self, other: Span) -> bool {
         self.data_untracked().ctxt == other.data_untracked().ctxt
     }
@@ -566,6 +560,13 @@ impl Span {
         self.ctxt() != SyntaxContext::root()
     }
 
+    /// Returns `true` if `span` originates in a macro's expansion where debuginfo should be
+    /// collapsed.
+    pub fn in_macro_expansion_with_collapse_debuginfo(self) -> bool {
+        let outer_expn = self.ctxt().outer_expn_data();
+        matches!(outer_expn.kind, ExpnKind::Macro(..)) && outer_expn.collapse_debuginfo
+    }
+
     /// Returns `true` if `span` originates in a derive-macro's expansion.
     pub fn in_derive_expansion(self) -> bool {
         matches!(self.ctxt().outer_expn_data().kind, ExpnKind::Macro(MacroKind::Derive, _))
@@ -1626,10 +1627,9 @@ impl SourceFile {
     /// number. If the source_file is empty or the position is located before the
     /// first line, `None` is returned.
     pub fn lookup_line(&self, pos: BytePos) -> Option<usize> {
-        self.lines(|lines| match lines.binary_search(&pos) {
-            Ok(idx) => Some(idx),
-            Err(0) => None,
-            Err(idx) => Some(idx - 1),
+        self.lines(|lines| match lines.partition_point(|x| x <= &pos) {
+            0 => None,
+            i => Some(i - 1),
         })
     }
 
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index a32cabab4c40..4d94c92d3f2b 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -23,7 +23,6 @@ use std::{convert::TryFrom, unreachable};
 
 use std::fs;
 use std::io;
-use tracing::debug;
 
 #[cfg(test)]
 mod tests;
@@ -1060,13 +1059,13 @@ impl FilePathMapping {
 
         return remap_path_prefix(&self.mapping, path);
 
-        #[instrument(level = "debug", skip(mapping))]
+        #[instrument(level = "debug", skip(mapping), ret)]
         fn remap_path_prefix(mapping: &[(PathBuf, PathBuf)], path: PathBuf) -> (PathBuf, bool) {
             // NOTE: We are iterating over the mapping entries from last to first
             //       because entries specified later on the command line should
             //       take precedence.
             for &(ref from, ref to) in mapping.iter().rev() {
-                debug!("Trying to apply {:?} => {:?}", from, to);
+                debug!("Trying to apply {from:?} => {to:?}");
 
                 if let Ok(rest) = path.strip_prefix(from) {
                     let remapped = if rest.as_os_str().is_empty() {
@@ -1080,15 +1079,15 @@ impl FilePathMapping {
                     } else {
                         to.join(rest)
                     };
-                    debug!("Match - remapped {:?} => {:?}", path, remapped);
+                    debug!("Match - remapped");
 
                     return (remapped, true);
                 } else {
-                    debug!("No match - prefix {:?} does not match {:?}", from, path);
+                    debug!("No match - prefix {from:?} does not match");
                 }
             }
 
-            debug!("Path {:?} was not remapped", path);
+            debug!("not remapped");
             (path, false)
         }
     }
diff --git a/compiler/rustc_span/src/span_encoding.rs b/compiler/rustc_span/src/span_encoding.rs
index 3ee329e9736f..b3de67415940 100644
--- a/compiler/rustc_span/src/span_encoding.rs
+++ b/compiler/rustc_span/src/span_encoding.rs
@@ -28,12 +28,17 @@ use rustc_data_structures::fx::FxIndexSet;
 /// Inline (compressed) format:
 /// - `span.base_or_index == span_data.lo`
 /// - `span.len_or_tag == len == span_data.hi - span_data.lo` (must be `<= MAX_LEN`)
-/// - `span.ctxt == span_data.ctxt` (must be `<= MAX_CTXT`)
+/// - `span.ctxt_or_tag == span_data.ctxt` (must be `<= MAX_CTXT`)
+///
+/// Interned format with inline `SyntaxContext`:
+/// - `span.base_or_index == index` (indexes into the interner table)
+/// - `span.len_or_tag == LEN_TAG` (high bit set, all other bits are zero)
+/// - `span.ctxt_or_tag == span_data.ctxt` (must be `<= MAX_CTXT`)
 ///
 /// Interned format:
 /// - `span.base_or_index == index` (indexes into the interner table)
 /// - `span.len_or_tag == LEN_TAG` (high bit set, all other bits are zero)
-/// - `span.ctxt == 0`
+/// - `span.ctxt_or_tag == CTXT_TAG`
 ///
 /// The inline form uses 0 for the tag value (rather than 1) so that we don't
 /// need to mask out the tag bit when getting the length, and so that the
@@ -50,10 +55,10 @@ use rustc_data_structures::fx::FxIndexSet;
 ///   at 3 or 4, and then it drops off quickly from 8 onwards. 15 bits is enough
 ///   for 99.99%+ of cases, but larger values (sometimes 20+ bits) might occur
 ///   dozens of times in a typical crate.
-/// - `ctxt` is 16 bits in `Span` and 32 bits in `SpanData`, which means that
+/// - `ctxt_or_tag` is 16 bits in `Span` and 32 bits in `SpanData`, which means that
 ///   large `ctxt` values will cause interning. The number of bits needed for
 ///   `ctxt` values depend partly on the crate size and partly on the form of
-///   the code. No crates in `rustc-perf` need more than 15 bits for `ctxt`,
+///   the code. No crates in `rustc-perf` need more than 15 bits for `ctxt_or_tag`,
 ///   but larger crates might need more than 16 bits.
 ///
 /// In order to reliably use parented spans in incremental compilation,
@@ -65,15 +70,16 @@ use rustc_data_structures::fx::FxIndexSet;
 pub struct Span {
     base_or_index: u32,
     len_or_tag: u16,
-    ctxt_or_zero: u16,
+    ctxt_or_tag: u16,
 }
 
 const LEN_TAG: u16 = 0b1000_0000_0000_0000;
 const MAX_LEN: u32 = 0b0111_1111_1111_1111;
-const MAX_CTXT: u32 = 0b1111_1111_1111_1111;
+const CTXT_TAG: u32 = 0b1111_1111_1111_1111;
+const MAX_CTXT: u32 = CTXT_TAG - 1;
 
 /// Dummy span, both position and length are zero, syntax context is zero as well.
-pub const DUMMY_SP: Span = Span { base_or_index: 0, len_or_tag: 0, ctxt_or_zero: 0 };
+pub const DUMMY_SP: Span = Span { base_or_index: 0, len_or_tag: 0, ctxt_or_tag: 0 };
 
 impl Span {
     #[inline]
@@ -91,12 +97,13 @@ impl Span {
 
         if len <= MAX_LEN && ctxt2 <= MAX_CTXT && parent.is_none() {
             // Inline format.
-            Span { base_or_index: base, len_or_tag: len as u16, ctxt_or_zero: ctxt2 as u16 }
+            Span { base_or_index: base, len_or_tag: len as u16, ctxt_or_tag: ctxt2 as u16 }
         } else {
             // Interned format.
             let index =
                 with_span_interner(|interner| interner.intern(&SpanData { lo, hi, ctxt, parent }));
-            Span { base_or_index: index, len_or_tag: LEN_TAG, ctxt_or_zero: 0 }
+            let ctxt_or_tag = if ctxt2 <= MAX_CTXT { ctxt2 } else { CTXT_TAG } as u16;
+            Span { base_or_index: index, len_or_tag: LEN_TAG, ctxt_or_tag }
         }
     }
 
@@ -119,16 +126,29 @@ impl Span {
             SpanData {
                 lo: BytePos(self.base_or_index),
                 hi: BytePos(self.base_or_index + self.len_or_tag as u32),
-                ctxt: SyntaxContext::from_u32(self.ctxt_or_zero as u32),
+                ctxt: SyntaxContext::from_u32(self.ctxt_or_tag as u32),
                 parent: None,
             }
         } else {
             // Interned format.
-            debug_assert!(self.ctxt_or_zero == 0);
             let index = self.base_or_index;
             with_span_interner(|interner| interner.spans[index as usize])
         }
     }
+
+    /// This function is used as a fast path when decoding the full `SpanData` is not necessary.
+    #[inline]
+    pub fn ctxt(self) -> SyntaxContext {
+        let ctxt_or_tag = self.ctxt_or_tag as u32;
+        if ctxt_or_tag <= MAX_CTXT {
+            // Inline format or interned format with inline ctxt.
+            SyntaxContext::from_u32(ctxt_or_tag)
+        } else {
+            // Interned format.
+            let index = self.base_or_index;
+            with_span_interner(|interner| interner.spans[index as usize].ctxt)
+        }
+    }
 }
 
 #[derive(Default)]
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 6eca7dc52b26..502ef67fc676 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -125,7 +125,7 @@ symbols! {
     Symbols {
         AcqRel,
         Acquire,
-        AddSubdiagnostic,
+        AddToDiagnostic,
         Alignment,
         Any,
         Arc,
@@ -210,10 +210,12 @@ symbols! {
         Implied,
         Input,
         Into,
+        IntoDiagnostic,
         IntoFuture,
         IntoIterator,
         IoRead,
         IoWrite,
+        IpAddr,
         IrTyKind,
         Is,
         ItemContext,
@@ -223,6 +225,7 @@ symbols! {
         LinkedList,
         LintPass,
         Mutex,
+        MutexGuard,
         N,
         NonZeroI128,
         NonZeroI16,
@@ -271,9 +274,10 @@ symbols! {
         Rust,
         RustcDecodable,
         RustcEncodable,
+        RwLockReadGuard,
+        RwLockWriteGuard,
         Send,
         SeqCst,
-        SessionDiagnostic,
         SliceIndex,
         Some,
         String,
@@ -336,6 +340,7 @@ symbols! {
         alias,
         align,
         align_offset,
+        alignment,
         alignstack,
         all,
         alloc,
@@ -391,6 +396,7 @@ symbols! {
         assume_init,
         async_await,
         async_closure,
+        async_fn_in_trait,
         atomic,
         atomic_mod,
         atomics,
@@ -483,6 +489,7 @@ symbols! {
         cmse_nonsecure_entry,
         coerce_unsized,
         cold,
+        collapse_debuginfo,
         column,
         column_macro,
         compare_and_swap,
@@ -506,7 +513,6 @@ symbols! {
         const_deallocate,
         const_eval_limit,
         const_eval_select,
-        const_eval_select_ct,
         const_evaluatable_checked,
         const_extern_fn,
         const_fn,
@@ -646,6 +652,7 @@ symbols! {
         dropck_parametricity,
         dylib,
         dyn_metadata,
+        dyn_star,
         dyn_trait,
         e,
         edition_macro_pats,
@@ -658,7 +665,6 @@ symbols! {
         emit_struct,
         emit_struct_field,
         enable,
-        enclosing_scope,
         encode,
         end,
         env,
@@ -761,7 +767,7 @@ symbols! {
         gen_future,
         gen_kill,
         generator,
-        generator_return,
+        generator_clone,
         generator_state,
         generators,
         generic_arg_infer,
@@ -820,6 +826,7 @@ symbols! {
         infer_outlives_requirements,
         infer_static_outlives_requirements,
         inherent_associated_types,
+        inherit,
         inlateout,
         inline,
         inline_const,
@@ -862,6 +869,7 @@ symbols! {
         lib,
         libc,
         lifetime,
+        lifetimes,
         likely,
         line,
         line_macro,
@@ -1059,6 +1067,7 @@ symbols! {
         panic_unwind,
         panicking,
         param_attrs,
+        parent_label,
         partial_cmp,
         partial_ord,
         passes,
@@ -1113,8 +1122,7 @@ symbols! {
         profiler_builtins,
         profiler_runtime,
         ptr,
-        ptr_guaranteed_eq,
-        ptr_guaranteed_ne,
+        ptr_guaranteed_cmp,
         ptr_mask,
         ptr_null,
         ptr_null_mut,
@@ -1178,6 +1186,7 @@ symbols! {
         require,
         residual,
         result,
+        return_position_impl_trait_in_trait,
         rhs,
         rintf32,
         rintf64,
@@ -1233,6 +1242,7 @@ symbols! {
         rustc_dump_program_clauses,
         rustc_dump_user_substs,
         rustc_dump_vtable,
+        rustc_effective_visibility,
         rustc_error,
         rustc_evaluate_where_clauses,
         rustc_expected_cgu_reuse,
@@ -1286,9 +1296,11 @@ symbols! {
         rustc_variance,
         rustdoc,
         rustdoc_internals,
+        rustdoc_missing_doc_code_examples,
         rustfmt,
         rvalue_static_promotion,
         s,
+        safety,
         sanitize,
         sanitizer_runtime,
         saturating_add,
@@ -1302,6 +1314,8 @@ symbols! {
         should_panic,
         shr,
         shr_assign,
+        sig_dfl,
+        sig_ign,
         simd,
         simd_add,
         simd_and,
@@ -1309,9 +1323,11 @@ symbols! {
         simd_as,
         simd_bitmask,
         simd_cast,
+        simd_cast_ptr,
         simd_ceil,
         simd_div,
         simd_eq,
+        simd_expose_addr,
         simd_extract,
         simd_fabs,
         simd_fcos,
@@ -1327,6 +1343,7 @@ symbols! {
         simd_fmin,
         simd_fpow,
         simd_fpowi,
+        simd_from_exposed_addr,
         simd_fsin,
         simd_fsqrt,
         simd_gather,
@@ -1471,6 +1488,7 @@ symbols! {
         trait_alias,
         trait_upcasting,
         transmute,
+        transmute_opts,
         transmute_trait,
         transparent,
         transparent_enums,
@@ -1487,6 +1505,7 @@ symbols! {
         tuple,
         tuple_from_req,
         tuple_indexing,
+        tuple_trait,
         two_phase,
         ty,
         type_alias_enum_variants,
@@ -1520,6 +1539,7 @@ symbols! {
         unit,
         universal_impl_trait,
         unix,
+        unix_sigpipe,
         unlikely,
         unmarked_api,
         unpin,
@@ -1565,6 +1585,7 @@ symbols! {
         va_list,
         va_start,
         val,
+        validity,
         values,
         var,
         variant_count,
diff --git a/compiler/rustc_symbol_mangling/src/errors.rs b/compiler/rustc_symbol_mangling/src/errors.rs
index 242997365a89..eb487a03c93a 100644
--- a/compiler/rustc_symbol_mangling/src/errors.rs
+++ b/compiler/rustc_symbol_mangling/src/errors.rs
@@ -1,36 +1,34 @@
 //! Errors emitted by symbol_mangling.
 
-use rustc_macros::SessionDiagnostic;
+use rustc_errors::{DiagnosticArgValue, IntoDiagnosticArg};
+use rustc_macros::Diagnostic;
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
-#[diag(symbol_mangling::invalid_symbol_name)]
-pub struct InvalidSymbolName {
+#[derive(Diagnostic)]
+#[diag(symbol_mangling::test_output)]
+pub struct TestOutput {
     #[primary_span]
     pub span: Span,
-    pub mangled_formatted: String,
+    pub kind: Kind,
+    pub content: String,
 }
 
-#[derive(SessionDiagnostic)]
-#[diag(symbol_mangling::invalid_trait_item)]
-pub struct InvalidTraitItem {
-    #[primary_span]
-    pub span: Span,
-    pub demangling_formatted: String,
+pub enum Kind {
+    SymbolName,
+    Demangling,
+    DemanglingAlt,
+    DefPath,
 }
 
-#[derive(SessionDiagnostic)]
-#[diag(symbol_mangling::alt_invalid_trait_item)]
-pub struct AltInvalidTraitItem {
-    #[primary_span]
-    pub span: Span,
-    pub alt_demangling_formatted: String,
-}
-
-#[derive(SessionDiagnostic)]
-#[diag(symbol_mangling::invalid_def_path)]
-pub struct InvalidDefPath {
-    #[primary_span]
-    pub span: Span,
-    pub def_path: String,
+impl IntoDiagnosticArg for Kind {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        let kind = match self {
+            Kind::SymbolName => "symbol-name",
+            Kind::Demangling => "demangling",
+            Kind::DemanglingAlt => "demangling-alt",
+            Kind::DefPath => "def-path",
+        }
+        .into();
+        DiagnosticArgValue::Str(kind)
+    }
 }
diff --git a/compiler/rustc_symbol_mangling/src/legacy.rs b/compiler/rustc_symbol_mangling/src/legacy.rs
index 9241fd82c745..46c5fe78ffbf 100644
--- a/compiler/rustc_symbol_mangling/src/legacy.rs
+++ b/compiler/rustc_symbol_mangling/src/legacy.rs
@@ -6,8 +6,6 @@ use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeVisitable};
 use rustc_middle::util::common::record_time;
 
-use tracing::debug;
-
 use std::fmt::{self, Write};
 use std::mem::{self, discriminant};
 
diff --git a/compiler/rustc_symbol_mangling/src/lib.rs b/compiler/rustc_symbol_mangling/src/lib.rs
index 0c6489acb348..62f44a48032e 100644
--- a/compiler/rustc_symbol_mangling/src/lib.rs
+++ b/compiler/rustc_symbol_mangling/src/lib.rs
@@ -97,6 +97,9 @@
 #[macro_use]
 extern crate rustc_middle;
 
+#[macro_use]
+extern crate tracing;
+
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
@@ -107,8 +110,6 @@ use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, Instance, TyCtxt};
 use rustc_session::config::SymbolManglingVersion;
 
-use tracing::debug;
-
 mod legacy;
 mod v0;
 
diff --git a/compiler/rustc_symbol_mangling/src/test.rs b/compiler/rustc_symbol_mangling/src/test.rs
index b1c4cab11eb8..c8c6fe2bf852 100644
--- a/compiler/rustc_symbol_mangling/src/test.rs
+++ b/compiler/rustc_symbol_mangling/src/test.rs
@@ -4,7 +4,7 @@
 //! def-path. This is used for unit testing the code that generates
 //! paths etc in all kinds of annoying scenarios.
 
-use crate::errors::{AltInvalidTraitItem, InvalidDefPath, InvalidSymbolName, InvalidTraitItem};
+use crate::errors::{Kind, TestOutput};
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{subst::InternalSubsts, Instance, TyCtxt};
@@ -26,19 +26,19 @@ pub fn report_symbol_names(tcx: TyCtxt<'_>) {
         let crate_items = tcx.hir_crate_items(());
 
         for id in crate_items.items() {
-            symbol_names.process_attrs(id.def_id);
+            symbol_names.process_attrs(id.def_id.def_id);
         }
 
         for id in crate_items.trait_items() {
-            symbol_names.process_attrs(id.def_id);
+            symbol_names.process_attrs(id.def_id.def_id);
         }
 
         for id in crate_items.impl_items() {
-            symbol_names.process_attrs(id.def_id);
+            symbol_names.process_attrs(id.def_id.def_id);
         }
 
         for id in crate_items.foreign_items() {
-            symbol_names.process_attrs(id.def_id);
+            symbol_names.process_attrs(id.def_id.def_id);
         }
     })
 }
@@ -60,26 +60,30 @@ impl SymbolNamesTest<'_> {
                 tcx.erase_regions(InternalSubsts::identity_for_item(tcx, def_id)),
             );
             let mangled = tcx.symbol_name(instance);
-            tcx.sess.emit_err(InvalidSymbolName {
+            tcx.sess.emit_err(TestOutput {
                 span: attr.span,
-                mangled_formatted: format!("{mangled}"),
+                kind: Kind::SymbolName,
+                content: format!("{mangled}"),
             });
             if let Ok(demangling) = rustc_demangle::try_demangle(mangled.name) {
-                tcx.sess.emit_err(InvalidTraitItem {
+                tcx.sess.emit_err(TestOutput {
                     span: attr.span,
-                    demangling_formatted: format!("{demangling}"),
+                    kind: Kind::Demangling,
+                    content: format!("{demangling}"),
                 });
-                tcx.sess.emit_err(AltInvalidTraitItem {
+                tcx.sess.emit_err(TestOutput {
                     span: attr.span,
-                    alt_demangling_formatted: format!("{:#}", demangling),
+                    kind: Kind::DemanglingAlt,
+                    content: format!("{:#}", demangling),
                 });
             }
         }
 
         for attr in tcx.get_attrs(def_id.to_def_id(), DEF_PATH) {
-            tcx.sess.emit_err(InvalidDefPath {
+            tcx.sess.emit_err(TestOutput {
                 span: attr.span,
-                def_path: with_no_trimmed_paths!(tcx.def_path_str(def_id.to_def_id())),
+                kind: Kind::DefPath,
+                content: with_no_trimmed_paths!(tcx.def_path_str(def_id.to_def_id())),
             });
         }
     }
diff --git a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
index cb61f76af1d7..aa65a72ab646 100644
--- a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
+++ b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
@@ -13,7 +13,7 @@ use rustc_hir as hir;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
 use rustc_middle::ty::{
     self, Binder, Const, ExistentialPredicate, FloatTy, FnSig, IntTy, List, Region, RegionKind,
-    Term, Ty, TyCtxt, UintTy,
+    TermKind, Ty, TyCtxt, UintTy,
 };
 use rustc_span::def_id::DefId;
 use rustc_span::symbol::sym;
@@ -243,13 +243,9 @@ fn encode_predicate<'tcx>(
             let name = encode_ty_name(tcx, projection.item_def_id);
             let _ = write!(s, "u{}{}", name.len(), &name);
             s.push_str(&encode_substs(tcx, projection.substs, dict, options));
-            match projection.term {
-                Term::Ty(ty) => {
-                    s.push_str(&encode_ty(tcx, ty, dict, options));
-                }
-                Term::Const(c) => {
-                    s.push_str(&encode_const(tcx, c, dict, options));
-                }
+            match projection.term.unpack() {
+                TermKind::Ty(ty) => s.push_str(&encode_ty(tcx, ty, dict, options)),
+                TermKind::Const(c) => s.push_str(&encode_const(tcx, c, dict, options)),
             }
         }
         ty::ExistentialPredicate::AutoTrait(def_id) => {
@@ -309,8 +305,7 @@ fn encode_region<'tcx>(
         | RegionKind::ReFree(..)
         | RegionKind::ReStatic
         | RegionKind::ReVar(..)
-        | RegionKind::RePlaceholder(..)
-        | RegionKind::ReEmpty(..) => {
+        | RegionKind::RePlaceholder(..) => {
             bug!("encode_region: unexpected `{:?}`", region.kind());
         }
     }
@@ -632,10 +627,13 @@ fn encode_ty<'tcx>(
         }
 
         // Trait types
-        ty::Dynamic(predicates, region) => {
+        ty::Dynamic(predicates, region, kind) => {
             // u3dynI<element-type1[..element-typeN]>E, where <element-type> is <predicate>, as
             // vendor extended type.
-            let mut s = String::from("u3dynI");
+            let mut s = String::from(match kind {
+                ty::Dyn => "u3dynI",
+                ty::DynStar => "u7dynstarI",
+            });
             s.push_str(&encode_predicates(tcx, predicates, dict, options));
             s.push_str(&encode_region(tcx, *region, dict, options));
             s.push('E');
diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs
index 71fa5a448870..18e7e74741af 100644
--- a/compiler/rustc_symbol_mangling/src/v0.rs
+++ b/compiler/rustc_symbol_mangling/src/v0.rs
@@ -7,10 +7,10 @@ use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
 use rustc_middle::ty::layout::IntegerExt;
 use rustc_middle::ty::print::{Print, Printer};
-use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst};
 use rustc_middle::ty::{
     self, EarlyBinder, FloatTy, Instance, IntTy, Ty, TyCtxt, TypeVisitable, UintTy,
 };
+use rustc_middle::ty::{GenericArg, GenericArgKind};
 use rustc_span::symbol::kw;
 use rustc_target::abi::Integer;
 use rustc_target::spec::abi::Abi;
@@ -479,8 +479,12 @@ impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
                 })?;
             }
 
-            ty::Dynamic(predicates, r) => {
-                self.push("D");
+            ty::Dynamic(predicates, r, kind) => {
+                self.push(match kind {
+                    ty::Dyn => "D",
+                    // FIXME(dyn-star): need to update v0 mangling docs
+                    ty::DynStar => "D*",
+                });
                 self = self.print_dyn_existential(predicates)?;
                 self = r.print(self)?;
             }
@@ -543,9 +547,9 @@ impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
                         let name = cx.tcx.associated_item(projection.item_def_id).name;
                         cx.push("p");
                         cx.push_ident(name.as_str());
-                        cx = match projection.term {
-                            ty::Term::Ty(ty) => ty.print(cx),
-                            ty::Term::Const(c) => c.print(cx),
+                        cx = match projection.term.unpack() {
+                            ty::TermKind::Ty(ty) => ty.print(cx),
+                            ty::TermKind::Const(c) => c.print(cx),
                         }?;
                     }
                     ty::ExistentialPredicate::AutoTrait(def_id) => {
diff --git a/compiler/rustc_target/Cargo.toml b/compiler/rustc_target/Cargo.toml
index 162376af45f1..fc37fdb1c43c 100644
--- a/compiler/rustc_target/Cargo.toml
+++ b/compiler/rustc_target/Cargo.toml
@@ -8,7 +8,8 @@ bitflags = "1.2.1"
 tracing = "0.1"
 serde_json = "1.0.59"
 rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_feature = { path = "../rustc_feature" }
+rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
-rustc_index = { path = "../rustc_index" }
diff --git a/compiler/rustc_target/src/abi/call/aarch64.rs b/compiler/rustc_target/src/abi/call/aarch64.rs
index 8a5ad90db71f..a84988fa75c6 100644
--- a/compiler/rustc_target/src/abi/call/aarch64.rs
+++ b/compiler/rustc_target/src/abi/call/aarch64.rs
@@ -1,6 +1,27 @@
 use crate::abi::call::{ArgAbi, FnAbi, Reg, RegKind, Uniform};
 use crate::abi::{HasDataLayout, TyAbiInterface};
 
+/// Given integer-types M and register width N (e.g. M=u16 and N=32 bits), the
+/// `ParamExtension` policy specifies how a uM value should be treated when
+/// passed via register or stack-slot of width N. See also rust-lang/rust#97463.
+#[derive(Copy, Clone, PartialEq)]
+pub enum ParamExtension {
+    /// Indicates that when passing an i8/i16, either as a function argument or
+    /// as a return value, it must be sign-extended to 32 bits, and likewise a
+    /// u8/u16 must be zero-extended to 32-bits. (This variant is here to
+    /// accommodate Apple's deviation from the usual AArch64 ABI as defined by
+    /// ARM.)
+    ///
+    /// See also: <https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Pass-Arguments-to-Functions-Correctly>
+    ExtendTo32Bits,
+
+    /// Indicates that no sign- nor zero-extension is performed: if a value of
+    /// type with bitwidth M is passed as function argument or return value,
+    /// then M bits are copied into the least significant M bits, and the
+    /// remaining bits of the register (or word of memory) are untouched.
+    NoExtension,
+}
+
 fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>) -> Option<Uniform>
 where
     Ty: TyAbiInterface<'a, C> + Copy,
@@ -24,13 +45,16 @@ where
     })
 }
 
-fn classify_ret<'a, Ty, C>(cx: &C, ret: &mut ArgAbi<'a, Ty>)
+fn classify_ret<'a, Ty, C>(cx: &C, ret: &mut ArgAbi<'a, Ty>, param_policy: ParamExtension)
 where
     Ty: TyAbiInterface<'a, C> + Copy,
     C: HasDataLayout,
 {
     if !ret.layout.is_aggregate() {
-        ret.extend_integer_width_to(32);
+        match param_policy {
+            ParamExtension::ExtendTo32Bits => ret.extend_integer_width_to(32),
+            ParamExtension::NoExtension => {}
+        }
         return;
     }
     if let Some(uniform) = is_homogeneous_aggregate(cx, ret) {
@@ -46,13 +70,16 @@ where
     ret.make_indirect();
 }
 
-fn classify_arg<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>)
+fn classify_arg<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>, param_policy: ParamExtension)
 where
     Ty: TyAbiInterface<'a, C> + Copy,
     C: HasDataLayout,
 {
     if !arg.layout.is_aggregate() {
-        arg.extend_integer_width_to(32);
+        match param_policy {
+            ParamExtension::ExtendTo32Bits => arg.extend_integer_width_to(32),
+            ParamExtension::NoExtension => {}
+        }
         return;
     }
     if let Some(uniform) = is_homogeneous_aggregate(cx, arg) {
@@ -68,19 +95,19 @@ where
     arg.make_indirect();
 }
 
-pub fn compute_abi_info<'a, Ty, C>(cx: &C, fn_abi: &mut FnAbi<'a, Ty>)
+pub fn compute_abi_info<'a, Ty, C>(cx: &C, fn_abi: &mut FnAbi<'a, Ty>, param_policy: ParamExtension)
 where
     Ty: TyAbiInterface<'a, C> + Copy,
     C: HasDataLayout,
 {
     if !fn_abi.ret.is_ignore() {
-        classify_ret(cx, &mut fn_abi.ret);
+        classify_ret(cx, &mut fn_abi.ret, param_policy);
     }
 
     for arg in fn_abi.args.iter_mut() {
         if arg.is_ignore() {
             continue;
         }
-        classify_arg(cx, arg);
+        classify_arg(cx, arg, param_policy);
     }
 }
diff --git a/compiler/rustc_target/src/abi/call/mod.rs b/compiler/rustc_target/src/abi/call/mod.rs
index d2eb804d0048..d2fb8c32ffd2 100644
--- a/compiler/rustc_target/src/abi/call/mod.rs
+++ b/compiler/rustc_target/src/abi/call/mod.rs
@@ -685,7 +685,14 @@ impl<'a, Ty> FnAbi<'a, Ty> {
                     }
                 }
             },
-            "aarch64" => aarch64::compute_abi_info(cx, self),
+            "aarch64" => {
+                let param_policy = if cx.target_spec().is_like_osx {
+                    aarch64::ParamExtension::ExtendTo32Bits
+                } else {
+                    aarch64::ParamExtension::NoExtension
+                };
+                aarch64::compute_abi_info(cx, self, param_policy)
+            }
             "amdgpu" => amdgpu::compute_abi_info(cx, self),
             "arm" => arm::compute_abi_info(cx, self),
             "avr" => avr::compute_abi_info(self),
diff --git a/compiler/rustc_target/src/abi/mod.rs b/compiler/rustc_target/src/abi/mod.rs
index 92ce4d91d84d..ec334e5887ab 100644
--- a/compiler/rustc_target/src/abi/mod.rs
+++ b/compiler/rustc_target/src/abi/mod.rs
@@ -7,7 +7,7 @@ use crate::spec::Target;
 use std::convert::{TryFrom, TryInto};
 use std::fmt;
 use std::iter::Step;
-use std::num::NonZeroUsize;
+use std::num::{NonZeroUsize, ParseIntError};
 use std::ops::{Add, AddAssign, Deref, Mul, RangeInclusive, Sub};
 use std::str::FromStr;
 
@@ -69,34 +69,46 @@ impl Default for TargetDataLayout {
     }
 }
 
+pub enum TargetDataLayoutErrors<'a> {
+    InvalidAddressSpace { addr_space: &'a str, cause: &'a str, err: ParseIntError },
+    InvalidBits { kind: &'a str, bit: &'a str, cause: &'a str, err: ParseIntError },
+    MissingAlignment { cause: &'a str },
+    InvalidAlignment { cause: &'a str, err: String },
+    InconsistentTargetArchitecture { dl: &'a str, target: &'a str },
+    InconsistentTargetPointerWidth { pointer_size: u64, target: u32 },
+    InvalidBitsSize { err: String },
+}
+
 impl TargetDataLayout {
-    pub fn parse(target: &Target) -> Result<TargetDataLayout, String> {
+    pub fn parse<'a>(target: &'a Target) -> Result<TargetDataLayout, TargetDataLayoutErrors<'a>> {
         // Parse an address space index from a string.
-        let parse_address_space = |s: &str, cause: &str| {
+        let parse_address_space = |s: &'a str, cause: &'a str| {
             s.parse::<u32>().map(AddressSpace).map_err(|err| {
-                format!("invalid address space `{}` for `{}` in \"data-layout\": {}", s, cause, err)
+                TargetDataLayoutErrors::InvalidAddressSpace { addr_space: s, cause, err }
             })
         };
 
         // Parse a bit count from a string.
-        let parse_bits = |s: &str, kind: &str, cause: &str| {
-            s.parse::<u64>().map_err(|err| {
-                format!("invalid {} `{}` for `{}` in \"data-layout\": {}", kind, s, cause, err)
+        let parse_bits = |s: &'a str, kind: &'a str, cause: &'a str| {
+            s.parse::<u64>().map_err(|err| TargetDataLayoutErrors::InvalidBits {
+                kind,
+                bit: s,
+                cause,
+                err,
             })
         };
 
         // Parse a size string.
-        let size = |s: &str, cause: &str| parse_bits(s, "size", cause).map(Size::from_bits);
+        let size = |s: &'a str, cause: &'a str| parse_bits(s, "size", cause).map(Size::from_bits);
 
         // Parse an alignment string.
-        let align = |s: &[&str], cause: &str| {
+        let align = |s: &[&'a str], cause: &'a str| {
             if s.is_empty() {
-                return Err(format!("missing alignment for `{}` in \"data-layout\"", cause));
+                return Err(TargetDataLayoutErrors::MissingAlignment { cause });
             }
             let align_from_bits = |bits| {
-                Align::from_bits(bits).map_err(|err| {
-                    format!("invalid alignment for `{}` in \"data-layout\": {}", cause, err)
-                })
+                Align::from_bits(bits)
+                    .map_err(|err| TargetDataLayoutErrors::InvalidAlignment { cause, err })
             };
             let abi = parse_bits(s[0], "alignment", cause)?;
             let pref = s.get(1).map_or(Ok(abi), |pref| parse_bits(pref, "alignment", cause))?;
@@ -158,25 +170,24 @@ impl TargetDataLayout {
 
         // Perform consistency checks against the Target information.
         if dl.endian != target.endian {
-            return Err(format!(
-                "inconsistent target specification: \"data-layout\" claims \
-                 architecture is {}-endian, while \"target-endian\" is `{}`",
-                dl.endian.as_str(),
-                target.endian.as_str(),
-            ));
+            return Err(TargetDataLayoutErrors::InconsistentTargetArchitecture {
+                dl: dl.endian.as_str(),
+                target: target.endian.as_str(),
+            });
         }
 
         let target_pointer_width: u64 = target.pointer_width.into();
         if dl.pointer_size.bits() != target_pointer_width {
-            return Err(format!(
-                "inconsistent target specification: \"data-layout\" claims \
-                 pointers are {}-bit, while \"target-pointer-width\" is `{}`",
-                dl.pointer_size.bits(),
-                target.pointer_width
-            ));
+            return Err(TargetDataLayoutErrors::InconsistentTargetPointerWidth {
+                pointer_size: dl.pointer_size.bits(),
+                target: target.pointer_width,
+            });
         }
 
-        dl.c_enum_min_size = Integer::from_size(Size::from_bits(target.c_enum_min_bits))?;
+        dl.c_enum_min_size = match Integer::from_size(Size::from_bits(target.c_enum_min_bits)) {
+            Ok(bits) => bits,
+            Err(err) => return Err(TargetDataLayoutErrors::InvalidBitsSize { err }),
+        };
 
         Ok(dl)
     }
@@ -1130,7 +1141,7 @@ pub enum TagEncoding {
 
     /// Niche (values invalid for a type) encoding the discriminant:
     /// Discriminant and variant index coincide.
-    /// The variant `dataful_variant` contains a niche at an arbitrary
+    /// The variant `untagged_variant` contains a niche at an arbitrary
     /// offset (field `tag_field` of the enum), which for a variant with
     /// discriminant `d` is set to
     /// `(d - niche_variants.start).wrapping_add(niche_start)`.
@@ -1139,7 +1150,7 @@ pub enum TagEncoding {
     /// `None` has a null pointer for the second tuple field, and
     /// `Some` is the identity function (with a non-null reference).
     Niche {
-        dataful_variant: VariantIdx,
+        untagged_variant: VariantIdx,
         niche_variants: RangeInclusive<VariantIdx>,
         niche_start: u128,
     },
diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index 9c9e297849ed..aaba0d7f093a 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -11,7 +11,6 @@
 #![feature(assert_matches)]
 #![feature(associated_type_bounds)]
 #![feature(exhaustive_patterns)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
diff --git a/compiler/rustc_target/src/spec/aarch64_nintendo_switch_freestanding.rs b/compiler/rustc_target/src/spec/aarch64_nintendo_switch_freestanding.rs
index 1b7161fbb85c..b301ce68a1ce 100644
--- a/compiler/rustc_target/src/spec/aarch64_nintendo_switch_freestanding.rs
+++ b/compiler/rustc_target/src/spec/aarch64_nintendo_switch_freestanding.rs
@@ -18,7 +18,6 @@ pub fn target() -> Target {
             panic_strategy: PanicStrategy::Abort,
             position_independent_executables: true,
             dynamic_linking: true,
-            executables: true,
             relro_level: RelroLevel::Off,
             ..Default::default()
         },
diff --git a/compiler/rustc_target/src/spec/abi.rs b/compiler/rustc_target/src/spec/abi.rs
index 337554dc96e8..c915124434b2 100644
--- a/compiler/rustc_target/src/spec/abi.rs
+++ b/compiler/rustc_target/src/spec/abi.rs
@@ -1,6 +1,8 @@
 use std::fmt;
 
 use rustc_macros::HashStable_Generic;
+use rustc_span::symbol::sym;
+use rustc_span::{Span, Symbol};
 
 #[cfg(test)]
 mod tests;
@@ -94,6 +96,192 @@ pub fn all_names() -> Vec<&'static str> {
     AbiDatas.iter().map(|d| d.name).collect()
 }
 
+pub fn enabled_names(features: &rustc_feature::Features, span: Span) -> Vec<&'static str> {
+    AbiDatas
+        .iter()
+        .map(|d| d.name)
+        .filter(|name| is_enabled(features, span, name).is_ok())
+        .collect()
+}
+
+pub enum AbiDisabled {
+    Unstable { feature: Symbol, explain: &'static str },
+    Unrecognized,
+}
+
+fn gate_feature_post(
+    features: &rustc_feature::Features,
+    feature: Symbol,
+    span: Span,
+    explain: &'static str,
+) -> Result<(), AbiDisabled> {
+    if !features.enabled(feature) && !span.allows_unstable(feature) {
+        Err(AbiDisabled::Unstable { feature, explain })
+    } else {
+        Ok(())
+    }
+}
+
+pub fn is_enabled(
+    features: &rustc_feature::Features,
+    span: Span,
+    name: &str,
+) -> Result<(), AbiDisabled> {
+    match name {
+        // Stable
+        "Rust" | "C" | "cdecl" | "stdcall" | "fastcall" | "aapcs" | "win64" | "sysv64"
+        | "system" => Ok(()),
+        "rust-intrinsic" => {
+            gate_feature_post(features, sym::intrinsics, span, "intrinsics are subject to change")
+        }
+        "platform-intrinsic" => gate_feature_post(
+            features,
+            sym::platform_intrinsics,
+            span,
+            "platform intrinsics are experimental and possibly buggy",
+        ),
+        "vectorcall" => gate_feature_post(
+            features,
+            sym::abi_vectorcall,
+            span,
+            "vectorcall is experimental and subject to change",
+        ),
+        "thiscall" => gate_feature_post(
+            features,
+            sym::abi_thiscall,
+            span,
+            "thiscall is experimental and subject to change",
+        ),
+        "rust-call" => gate_feature_post(
+            features,
+            sym::unboxed_closures,
+            span,
+            "rust-call ABI is subject to change",
+        ),
+        "rust-cold" => gate_feature_post(
+            features,
+            sym::rust_cold_cc,
+            span,
+            "rust-cold is experimental and subject to change",
+        ),
+        "ptx-kernel" => gate_feature_post(
+            features,
+            sym::abi_ptx,
+            span,
+            "PTX ABIs are experimental and subject to change",
+        ),
+        "unadjusted" => gate_feature_post(
+            features,
+            sym::abi_unadjusted,
+            span,
+            "unadjusted ABI is an implementation detail and perma-unstable",
+        ),
+        "msp430-interrupt" => gate_feature_post(
+            features,
+            sym::abi_msp430_interrupt,
+            span,
+            "msp430-interrupt ABI is experimental and subject to change",
+        ),
+        "x86-interrupt" => gate_feature_post(
+            features,
+            sym::abi_x86_interrupt,
+            span,
+            "x86-interrupt ABI is experimental and subject to change",
+        ),
+        "amdgpu-kernel" => gate_feature_post(
+            features,
+            sym::abi_amdgpu_kernel,
+            span,
+            "amdgpu-kernel ABI is experimental and subject to change",
+        ),
+        "avr-interrupt" | "avr-non-blocking-interrupt" => gate_feature_post(
+            features,
+            sym::abi_avr_interrupt,
+            span,
+            "avr-interrupt and avr-non-blocking-interrupt ABIs are experimental and subject to change",
+        ),
+        "efiapi" => gate_feature_post(
+            features,
+            sym::abi_efiapi,
+            span,
+            "efiapi ABI is experimental and subject to change",
+        ),
+        "C-cmse-nonsecure-call" => gate_feature_post(
+            features,
+            sym::abi_c_cmse_nonsecure_call,
+            span,
+            "C-cmse-nonsecure-call ABI is experimental and subject to change",
+        ),
+        "C-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "C-unwind ABI is experimental and subject to change",
+        ),
+        "stdcall-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "stdcall-unwind ABI is experimental and subject to change",
+        ),
+        "system-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "system-unwind ABI is experimental and subject to change",
+        ),
+        "thiscall-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "thiscall-unwind ABI is experimental and subject to change",
+        ),
+        "cdecl-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "cdecl-unwind ABI is experimental and subject to change",
+        ),
+        "fastcall-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "fastcall-unwind ABI is experimental and subject to change",
+        ),
+        "vectorcall-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "vectorcall-unwind ABI is experimental and subject to change",
+        ),
+        "aapcs-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "aapcs-unwind ABI is experimental and subject to change",
+        ),
+        "win64-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "win64-unwind ABI is experimental and subject to change",
+        ),
+        "sysv64-unwind" => gate_feature_post(
+            features,
+            sym::c_unwind,
+            span,
+            "sysv64-unwind ABI is experimental and subject to change",
+        ),
+        "wasm" => gate_feature_post(
+            features,
+            sym::wasm_abi,
+            span,
+            "wasm ABI is experimental and subject to change",
+        ),
+        _ => Err(AbiDisabled::Unrecognized),
+    }
+}
+
 impl Abi {
     /// Default ABI chosen for `extern fn` declarations without an explicit ABI.
     pub const FALLBACK: Abi = Abi::C { unwind: false };
diff --git a/compiler/rustc_target/src/spec/android_base.rs b/compiler/rustc_target/src/spec/android_base.rs
index 2bf83a8782a1..9c1df1a06778 100644
--- a/compiler/rustc_target/src/spec/android_base.rs
+++ b/compiler/rustc_target/src/spec/android_base.rs
@@ -1,11 +1,12 @@
-use crate::spec::TargetOptions;
+use crate::spec::{SanitizerSet, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let mut base = super::linux_base::opts();
     base.os = "android".into();
+    base.is_like_android = true;
     base.default_dwarf_version = 2;
-    base.position_independent_executables = true;
     base.has_thread_local = false;
+    base.supported_sanitizers = SanitizerSet::ADDRESS;
     // This is for backward compatibility, see https://github.com/rust-lang/rust/issues/49867
     // for context. (At that time, there was no `-C force-unwind-tables`, so the only solution
     // was to always emit `uwtable`).
diff --git a/compiler/rustc_target/src/spec/apple_base.rs b/compiler/rustc_target/src/spec/apple_base.rs
index 9bbee88a894c..2c72bf88a41e 100644
--- a/compiler/rustc_target/src/spec/apple_base.rs
+++ b/compiler/rustc_target/src/spec/apple_base.rs
@@ -1,40 +1,37 @@
 use std::{borrow::Cow, env};
 
-use crate::spec::{cvs, DebuginfoKind, FramePointer, SplitDebuginfo, TargetOptions};
+use crate::spec::{cvs, DebuginfoKind, FramePointer, SplitDebuginfo, StaticCow, TargetOptions};
 use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor};
 
 fn pre_link_args(os: &'static str, arch: &'static str, abi: &'static str) -> LinkArgs {
-    let mut args = LinkArgs::new();
-
-    let platform_name = match abi {
-        "sim" => format!("{}-simulator", os),
-        "macabi" => "mac-catalyst".to_string(),
-        _ => os.to_string(),
+    let platform_name: StaticCow<str> = match abi {
+        "sim" => format!("{}-simulator", os).into(),
+        "macabi" => "mac-catalyst".into(),
+        _ => os.into(),
     };
 
-    let platform_version = match os.as_ref() {
+    let platform_version: StaticCow<str> = match os.as_ref() {
         "ios" => ios_lld_platform_version(),
         "tvos" => tvos_lld_platform_version(),
         "watchos" => watchos_lld_platform_version(),
         "macos" => macos_lld_platform_version(arch),
         _ => unreachable!(),
-    };
-
-    if abi != "macabi" {
-        args.insert(LinkerFlavor::Gcc, vec!["-arch".into(), arch.into()]);
     }
+    .into();
 
-    args.insert(
+    let mut args = TargetOptions::link_args(
         LinkerFlavor::Lld(LldFlavor::Ld64),
-        vec![
-            "-arch".into(),
-            arch.into(),
-            "-platform_version".into(),
-            platform_name.into(),
-            platform_version.clone().into(),
-            platform_version.into(),
-        ],
+        &["-arch", arch, "-platform_version"],
     );
+    // Manually add owned args unsupported by link arg building helpers.
+    args.entry(LinkerFlavor::Lld(LldFlavor::Ld64)).or_default().extend([
+        platform_name,
+        platform_version.clone(),
+        platform_version,
+    ]);
+    if abi != "macabi" {
+        super::add_link_args(&mut args, LinkerFlavor::Gcc, &["-arch", arch]);
+    }
 
     args
 }
@@ -127,7 +124,7 @@ pub fn macos_llvm_target(arch: &str) -> String {
     format!("{}-apple-macosx{}.{}.0", arch, major, minor)
 }
 
-pub fn macos_link_env_remove() -> Vec<Cow<'static, str>> {
+pub fn macos_link_env_remove() -> Vec<StaticCow<str>> {
     let mut env_remove = Vec::with_capacity(2);
     // Remove the `SDKROOT` environment variable if it's clearly set for the wrong platform, which
     // may occur when we're linking a custom build script while targeting iOS for example.
diff --git a/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs b/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs
new file mode 100644
index 000000000000..4836f3cf7202
--- /dev/null
+++ b/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs
@@ -0,0 +1,19 @@
+use crate::abi::Endian;
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "armeb-unknown-linux-gnueabi".into(),
+        pointer_width: 32,
+        data_layout: "E-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".into(),
+        arch: "arm".into(),
+        options: TargetOptions {
+            abi: "eabi".into(),
+            features: "+strict-align,+v8,+crc".into(),
+            endian: Endian::Big,
+            max_atomic_width: Some(64),
+            mcount: "\u{1}__gnu_mcount_nc".into(),
+            ..super::linux_gnu_base::opts()
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/spec/armv5te_none_eabi.rs b/compiler/rustc_target/src/spec/armv5te_none_eabi.rs
new file mode 100644
index 000000000000..dfd27b654746
--- /dev/null
+++ b/compiler/rustc_target/src/spec/armv5te_none_eabi.rs
@@ -0,0 +1,41 @@
+//! Targets the ARMv5TE, with code as `a32` code by default.
+
+use crate::spec::{cvs, FramePointer, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "armv5te-none-eabi".into(),
+        pointer_width: 32,
+        arch: "arm".into(),
+        /* Data layout args are '-' separated:
+         * little endian
+         * stack is 64-bit aligned (EABI)
+         * pointers are 32-bit
+         * i64 must be 64-bit aligned (EABI)
+         * mangle names with ELF style
+         * native integers are 32-bit
+         * All other elements are default
+         */
+        data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".into(),
+
+        options: TargetOptions {
+            abi: "eabi".into(),
+            // extra args passed to the external assembler (assuming `arm-none-eabi-as`):
+            // * activate t32/a32 interworking
+            // * use arch ARMv5TE
+            // * use little-endian
+            asm_args: cvs!["-mthumb-interwork", "-march=armv5te", "-mlittle-endian",],
+            // minimum extra features, these cannot be disabled via -C
+            // Also force-enable 32-bit atomics, which allows the use of atomic load/store only.
+            // The resulting atomics are ABI incompatible with atomics backed by libatomic.
+            features: "+soft-float,+strict-align,+atomics-32".into(),
+            frame_pointer: FramePointer::MayOmit,
+            main_needs_argc_argv: false,
+            // don't have atomic compare-and-swap
+            atomic_cas: false,
+            has_thumb_interworking: true,
+
+            ..super::thumb_base::opts()
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/spec/asmjs_unknown_emscripten.rs b/compiler/rustc_target/src/spec/asmjs_unknown_emscripten.rs
index b4cf2c5ee229..f492c3451a41 100644
--- a/compiler/rustc_target/src/spec/asmjs_unknown_emscripten.rs
+++ b/compiler/rustc_target/src/spec/asmjs_unknown_emscripten.rs
@@ -2,6 +2,6 @@ use super::{wasm32_unknown_emscripten, LinkerFlavor, Target};
 
 pub fn target() -> Target {
     let mut target = wasm32_unknown_emscripten::target();
-    target.add_post_link_args(LinkerFlavor::Em, &["-sWASM=0", "--memory-init-file", "0"]);
+    target.add_post_link_args(LinkerFlavor::EmCc, &["-sWASM=0", "--memory-init-file", "0"]);
     target
 }
diff --git a/compiler/rustc_target/src/spec/avr_gnu_base.rs b/compiler/rustc_target/src/spec/avr_gnu_base.rs
index 1d441e558ddc..8cca33cc43b3 100644
--- a/compiler/rustc_target/src/spec/avr_gnu_base.rs
+++ b/compiler/rustc_target/src/spec/avr_gnu_base.rs
@@ -1,4 +1,4 @@
-use crate::spec::{LinkerFlavor, Target, TargetOptions};
+use crate::spec::{LinkerFlavor, RelocModel, Target, TargetOptions};
 
 /// A base target for AVR devices using the GNU toolchain.
 ///
@@ -21,6 +21,7 @@ pub fn target(target_cpu: &'static str, mmcu: &'static str) -> Target {
             late_link_args: TargetOptions::link_args(LinkerFlavor::Gcc, &["-lgcc"]),
             max_atomic_width: Some(0),
             atomic_cas: false,
+            relocation_model: RelocModel::Static,
             ..TargetOptions::default()
         },
     }
diff --git a/compiler/rustc_target/src/spec/bpf_base.rs b/compiler/rustc_target/src/spec/bpf_base.rs
index 3c4da6f883d9..baf36587147a 100644
--- a/compiler/rustc_target/src/spec/bpf_base.rs
+++ b/compiler/rustc_target/src/spec/bpf_base.rs
@@ -5,7 +5,7 @@ pub fn opts(endian: Endian) -> TargetOptions {
     TargetOptions {
         allow_asm: true,
         endian,
-        linker_flavor: LinkerFlavor::BpfLinker,
+        linker_flavor: LinkerFlavor::Bpf,
         atomic_cas: false,
         dynamic_linking: true,
         no_builtins: true,
diff --git a/compiler/rustc_target/src/spec/hexagon_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/hexagon_unknown_linux_musl.rs
index cc2c78c69fe1..2a24e4459c55 100644
--- a/compiler/rustc_target/src/spec/hexagon_unknown_linux_musl.rs
+++ b/compiler/rustc_target/src/spec/hexagon_unknown_linux_musl.rs
@@ -10,7 +10,6 @@ pub fn target() -> Target {
     base.crt_static_default = false;
     base.has_rpath = true;
     base.linker_is_gnu = false;
-    base.dynamic_linking = true;
 
     base.c_enum_min_bits = 8;
 
diff --git a/compiler/rustc_target/src/spec/i686_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/i686_unknown_linux_gnu.rs
index 765803d16928..f62029c90673 100644
--- a/compiler/rustc_target/src/spec/i686_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/i686_unknown_linux_gnu.rs
@@ -1,9 +1,10 @@
-use crate::spec::{LinkerFlavor, StackProbeType, Target};
+use crate::spec::{LinkerFlavor, SanitizerSet, StackProbeType, Target};
 
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
+    base.supported_sanitizers = SanitizerSet::ADDRESS;
     base.add_pre_link_args(LinkerFlavor::Gcc, &["-m32"]);
     // don't use probe-stack=inline-asm until rust#83139 and rust#84667 are resolved
     base.stack_probes = StackProbeType::Call;
diff --git a/compiler/rustc_target/src/spec/l4re_base.rs b/compiler/rustc_target/src/spec/l4re_base.rs
index a08756861e5b..b7bc1072bf32 100644
--- a/compiler/rustc_target/src/spec/l4re_base.rs
+++ b/compiler/rustc_target/src/spec/l4re_base.rs
@@ -1,14 +1,15 @@
-use crate::spec::{cvs, LinkerFlavor, PanicStrategy, TargetOptions};
+use crate::spec::{cvs, LinkerFlavor, PanicStrategy, RelocModel, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "l4re".into(),
         env: "uclibc".into(),
-        linker_flavor: LinkerFlavor::L4Bender,
+        linker_flavor: LinkerFlavor::Ld,
         panic_strategy: PanicStrategy::Abort,
         linker: Some("l4-bender".into()),
         linker_is_gnu: false,
         families: cvs!["unix"],
+        relocation_model: RelocModel::Static,
         ..Default::default()
     }
 }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index aa73625ff810..35b4cce50a02 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -92,14 +92,24 @@ mod windows_uwp_msvc_base;
 
 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
 pub enum LinkerFlavor {
-    Em,
     Gcc,
-    L4Bender,
     Ld,
-    Msvc,
     Lld(LldFlavor),
-    PtxLinker,
+    Msvc,
+    EmCc,
+    Bpf,
+    Ptx,
+}
+
+#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub enum LinkerFlavorCli {
+    Gcc,
+    Ld,
+    Lld(LldFlavor),
+    Msvc,
+    Em,
     BpfLinker,
+    PtxLinker,
 }
 
 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
@@ -137,19 +147,40 @@ impl ToJson for LldFlavor {
     }
 }
 
-impl ToJson for LinkerFlavor {
-    fn to_json(&self) -> Json {
-        self.desc().to_json()
+impl LinkerFlavor {
+    pub fn from_cli(cli: LinkerFlavorCli) -> LinkerFlavor {
+        match cli {
+            LinkerFlavorCli::Gcc => LinkerFlavor::Gcc,
+            LinkerFlavorCli::Ld => LinkerFlavor::Ld,
+            LinkerFlavorCli::Lld(lld_flavor) => LinkerFlavor::Lld(lld_flavor),
+            LinkerFlavorCli::Msvc => LinkerFlavor::Msvc,
+            LinkerFlavorCli::Em => LinkerFlavor::EmCc,
+            LinkerFlavorCli::BpfLinker => LinkerFlavor::Bpf,
+            LinkerFlavorCli::PtxLinker => LinkerFlavor::Ptx,
+        }
+    }
+
+    fn to_cli(self) -> LinkerFlavorCli {
+        match self {
+            LinkerFlavor::Gcc => LinkerFlavorCli::Gcc,
+            LinkerFlavor::Ld => LinkerFlavorCli::Ld,
+            LinkerFlavor::Lld(lld_flavor) => LinkerFlavorCli::Lld(lld_flavor),
+            LinkerFlavor::Msvc => LinkerFlavorCli::Msvc,
+            LinkerFlavor::EmCc => LinkerFlavorCli::Em,
+            LinkerFlavor::Bpf => LinkerFlavorCli::BpfLinker,
+            LinkerFlavor::Ptx => LinkerFlavorCli::PtxLinker,
+        }
     }
 }
-macro_rules! flavor_mappings {
-    ($((($($flavor:tt)*), $string:expr),)*) => (
-        impl LinkerFlavor {
+
+macro_rules! linker_flavor_cli_impls {
+    ($(($($flavor:tt)*) $string:literal)*) => (
+        impl LinkerFlavorCli {
             pub const fn one_of() -> &'static str {
                 concat!("one of: ", $($string, " ",)*)
             }
 
-            pub fn from_str(s: &str) -> Option<Self> {
+            pub fn from_str(s: &str) -> Option<LinkerFlavorCli> {
                 Some(match s {
                     $($string => $($flavor)*,)*
                     _ => return None,
@@ -165,18 +196,23 @@ macro_rules! flavor_mappings {
     )
 }
 
-flavor_mappings! {
-    ((LinkerFlavor::Em), "em"),
-    ((LinkerFlavor::Gcc), "gcc"),
-    ((LinkerFlavor::L4Bender), "l4-bender"),
-    ((LinkerFlavor::Ld), "ld"),
-    ((LinkerFlavor::Msvc), "msvc"),
-    ((LinkerFlavor::PtxLinker), "ptx-linker"),
-    ((LinkerFlavor::BpfLinker), "bpf-linker"),
-    ((LinkerFlavor::Lld(LldFlavor::Wasm)), "wasm-ld"),
-    ((LinkerFlavor::Lld(LldFlavor::Ld64)), "ld64.lld"),
-    ((LinkerFlavor::Lld(LldFlavor::Ld)), "ld.lld"),
-    ((LinkerFlavor::Lld(LldFlavor::Link)), "lld-link"),
+linker_flavor_cli_impls! {
+    (LinkerFlavorCli::Gcc) "gcc"
+    (LinkerFlavorCli::Ld) "ld"
+    (LinkerFlavorCli::Lld(LldFlavor::Ld)) "ld.lld"
+    (LinkerFlavorCli::Lld(LldFlavor::Ld64)) "ld64.lld"
+    (LinkerFlavorCli::Lld(LldFlavor::Link)) "lld-link"
+    (LinkerFlavorCli::Lld(LldFlavor::Wasm)) "wasm-ld"
+    (LinkerFlavorCli::Msvc) "msvc"
+    (LinkerFlavorCli::Em) "em"
+    (LinkerFlavorCli::BpfLinker) "bpf-linker"
+    (LinkerFlavorCli::PtxLinker) "ptx-linker"
+}
+
+impl ToJson for LinkerFlavorCli {
+    fn to_json(&self) -> Json {
+        self.desc().to_json()
+    }
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Hash, Encodable, Decodable, HashStable_Generic)]
@@ -467,6 +503,7 @@ impl fmt::Display for LinkOutputKind {
 }
 
 pub type LinkArgs = BTreeMap<LinkerFlavor, Vec<StaticCow<str>>>;
+pub type LinkArgsCli = BTreeMap<LinkerFlavorCli, Vec<StaticCow<str>>>;
 
 /// Which kind of debuginfo does the target use?
 ///
@@ -837,15 +874,15 @@ impl fmt::Display for StackProtector {
 }
 
 macro_rules! supported_targets {
-    ( $(($( $triple:literal, )+ $module:ident ),)+ ) => {
+    ( $(($triple:literal, $module:ident ),)+ ) => {
         $(mod $module;)+
 
         /// List of supported targets
-        pub const TARGETS: &[&str] = &[$($($triple),+),+];
+        pub const TARGETS: &[&str] = &[$($triple),+];
 
         fn load_builtin(target: &str) -> Option<Target> {
             let mut t = match target {
-                $( $($triple)|+ => $module::target(), )+
+                $( $triple => $module::target(), )+
                 _ => return None,
             };
             t.is_builtin = true;
@@ -861,7 +898,7 @@ macro_rules! supported_targets {
             $(
                 #[test] // `#[test]`
                 fn $module() {
-                    tests_impl::test_target(super::$module::target());
+                    tests_impl::test_target(super::$module::target(), $triple);
                 }
             )+
         }
@@ -895,6 +932,7 @@ supported_targets! {
     ("sparc64-unknown-linux-gnu", sparc64_unknown_linux_gnu),
     ("arm-unknown-linux-gnueabi", arm_unknown_linux_gnueabi),
     ("arm-unknown-linux-gnueabihf", arm_unknown_linux_gnueabihf),
+    ("armeb-unknown-linux-gnueabi", armeb_unknown_linux_gnueabi),
     ("arm-unknown-linux-musleabi", arm_unknown_linux_musleabi),
     ("arm-unknown-linux-musleabihf", arm_unknown_linux_musleabihf),
     ("armv4t-unknown-linux-gnueabi", armv4t_unknown_linux_gnueabi),
@@ -1082,6 +1120,8 @@ supported_targets! {
     ("mipsel-unknown-none", mipsel_unknown_none),
     ("thumbv4t-none-eabi", thumbv4t_none_eabi),
     ("armv4t-none-eabi", armv4t_none_eabi),
+    ("thumbv5te-none-eabi", thumbv5te_none_eabi),
+    ("armv5te-none-eabi", armv5te_none_eabi),
 
     ("aarch64_be-unknown-linux-gnu", aarch64_be_unknown_linux_gnu),
     ("aarch64-unknown-linux-gnu_ilp32", aarch64_unknown_linux_gnu_ilp32),
@@ -1210,19 +1250,21 @@ pub struct TargetOptions {
     pub abi: StaticCow<str>,
     /// Vendor name to use for conditional compilation (`target_vendor`). Defaults to "unknown".
     pub vendor: StaticCow<str>,
-    /// Default linker flavor used if `-C linker-flavor` or `-C linker` are not passed
-    /// on the command line. Defaults to `LinkerFlavor::Gcc`.
-    pub linker_flavor: LinkerFlavor,
 
     /// Linker to invoke
     pub linker: Option<StaticCow<str>>,
-
+    /// Default linker flavor used if `-C linker-flavor` or `-C linker` are not passed
+    /// on the command line. Defaults to `LinkerFlavor::Gcc`.
+    pub linker_flavor: LinkerFlavor,
+    linker_flavor_json: LinkerFlavorCli,
     /// LLD flavor used if `lld` (or `rust-lld`) is specified as a linker
     /// without clarifying its flavor in any way.
+    /// FIXME: Merge this into `LinkerFlavor`.
     pub lld_flavor: LldFlavor,
+    /// Whether the linker support GNU-like arguments such as -O. Defaults to true.
+    /// FIXME: Merge this into `LinkerFlavor`.
+    pub linker_is_gnu: bool,
 
-    /// Linker arguments that are passed *before* any user-defined libraries.
-    pub pre_link_args: LinkArgs,
     /// Objects to link before and after all other object code.
     pub pre_link_objects: CrtObjects,
     pub post_link_objects: CrtObjects,
@@ -1231,24 +1273,31 @@ pub struct TargetOptions {
     pub post_link_objects_self_contained: CrtObjects,
     pub link_self_contained: LinkSelfContainedDefault,
 
+    /// Linker arguments that are passed *before* any user-defined libraries.
+    pub pre_link_args: LinkArgs,
+    pre_link_args_json: LinkArgsCli,
     /// Linker arguments that are unconditionally passed after any
     /// user-defined but before post-link objects. Standard platform
     /// libraries that should be always be linked to, usually go here.
     pub late_link_args: LinkArgs,
+    late_link_args_json: LinkArgsCli,
     /// Linker arguments used in addition to `late_link_args` if at least one
     /// Rust dependency is dynamically linked.
     pub late_link_args_dynamic: LinkArgs,
+    late_link_args_dynamic_json: LinkArgsCli,
     /// Linker arguments used in addition to `late_link_args` if all Rust
     /// dependencies are statically linked.
     pub late_link_args_static: LinkArgs,
+    late_link_args_static_json: LinkArgsCli,
     /// Linker arguments that are unconditionally passed *after* any
     /// user-defined libraries.
     pub post_link_args: LinkArgs,
+    post_link_args_json: LinkArgsCli,
+
     /// Optional link script applied to `dylib` and `executable` crate types.
     /// This is a string containing the script, not a path. Can only be applied
     /// to linkers where `linker_is_gnu` is true.
     pub link_script: Option<StaticCow<str>>,
-
     /// Environment variables to be set for the linker invocation.
     pub link_env: StaticCow<[(StaticCow<str>, StaticCow<str>)]>,
     /// Environment variables to be removed for the linker invocation.
@@ -1305,6 +1354,8 @@ pub struct TargetOptions {
     pub abi_return_struct_as_int: bool,
     /// Whether the target toolchain is like macOS's. Only useful for compiling against iOS/macOS,
     /// in particular running dsymutil and some other stuff like `-dead_strip`. Defaults to false.
+    /// Also indiates whether to use Apple-specific ABI changes, such as extending function
+    /// parameters to 32-bits.
     pub is_like_osx: bool,
     /// Whether the target toolchain is like Solaris's.
     /// Only useful for compiling against Illumos/Solaris,
@@ -1330,11 +1381,11 @@ pub struct TargetOptions {
     pub is_like_msvc: bool,
     /// Whether a target toolchain is like WASM.
     pub is_like_wasm: bool,
+    /// Whether a target toolchain is like Android, implying a Linux kernel and a Bionic libc
+    pub is_like_android: bool,
     /// Default supported version of DWARF on this platform.
     /// Useful because some platforms (osx, bsd) only want up to DWARF2.
     pub default_dwarf_version: u32,
-    /// Whether the linker support GNU-like arguments such as -O. Defaults to true.
-    pub linker_is_gnu: bool,
     /// The MinGW toolchain has a known issue that prevents it from correctly
     /// handling COFF object files with more than 2<sup>15</sup> sections. Since each weak
     /// symbol needs its own COMDAT section, weak linkage implies a large
@@ -1528,15 +1579,11 @@ fn add_link_args(link_args: &mut LinkArgs, flavor: LinkerFlavor, args: &[&'stati
     match flavor {
         LinkerFlavor::Ld => insert(LinkerFlavor::Lld(LldFlavor::Ld)),
         LinkerFlavor::Msvc => insert(LinkerFlavor::Lld(LldFlavor::Link)),
-        LinkerFlavor::Lld(LldFlavor::Wasm) => {}
+        LinkerFlavor::Lld(LldFlavor::Ld64) | LinkerFlavor::Lld(LldFlavor::Wasm) => {}
         LinkerFlavor::Lld(lld_flavor) => {
             panic!("add_link_args: use non-LLD flavor for {:?}", lld_flavor)
         }
-        LinkerFlavor::Gcc
-        | LinkerFlavor::Em
-        | LinkerFlavor::L4Bender
-        | LinkerFlavor::BpfLinker
-        | LinkerFlavor::PtxLinker => {}
+        LinkerFlavor::Gcc | LinkerFlavor::EmCc | LinkerFlavor::Bpf | LinkerFlavor::Ptx => {}
     }
 }
 
@@ -1554,6 +1601,36 @@ impl TargetOptions {
     fn add_post_link_args(&mut self, flavor: LinkerFlavor, args: &[&'static str]) {
         add_link_args(&mut self.post_link_args, flavor, args);
     }
+
+    fn update_from_cli(&mut self) {
+        self.linker_flavor = LinkerFlavor::from_cli(self.linker_flavor_json);
+        for (args, args_json) in [
+            (&mut self.pre_link_args, &self.pre_link_args_json),
+            (&mut self.late_link_args, &self.late_link_args_json),
+            (&mut self.late_link_args_dynamic, &self.late_link_args_dynamic_json),
+            (&mut self.late_link_args_static, &self.late_link_args_static_json),
+            (&mut self.post_link_args, &self.post_link_args_json),
+        ] {
+            *args = args_json
+                .iter()
+                .map(|(flavor, args)| (LinkerFlavor::from_cli(*flavor), args.clone()))
+                .collect();
+        }
+    }
+
+    fn update_to_cli(&mut self) {
+        self.linker_flavor_json = self.linker_flavor.to_cli();
+        for (args, args_json) in [
+            (&self.pre_link_args, &mut self.pre_link_args_json),
+            (&self.late_link_args, &mut self.late_link_args_json),
+            (&self.late_link_args_dynamic, &mut self.late_link_args_dynamic_json),
+            (&self.late_link_args_static, &mut self.late_link_args_static_json),
+            (&self.post_link_args, &mut self.post_link_args_json),
+        ] {
+            *args_json =
+                args.iter().map(|(flavor, args)| (flavor.to_cli(), args.clone())).collect();
+        }
+    }
 }
 
 impl Default for TargetOptions {
@@ -1568,11 +1645,11 @@ impl Default for TargetOptions {
             env: "".into(),
             abi: "".into(),
             vendor: "unknown".into(),
-            linker_flavor: LinkerFlavor::Gcc,
             linker: option_env!("CFG_DEFAULT_LINKER").map(|s| s.into()),
+            linker_flavor: LinkerFlavor::Gcc,
+            linker_flavor_json: LinkerFlavorCli::Gcc,
             lld_flavor: LldFlavor::Ld,
-            pre_link_args: LinkArgs::new(),
-            post_link_args: LinkArgs::new(),
+            linker_is_gnu: true,
             link_script: None,
             asm_args: cvs![],
             cpu: "generic".into(),
@@ -1598,8 +1675,8 @@ impl Default for TargetOptions {
             is_like_windows: false,
             is_like_msvc: false,
             is_like_wasm: false,
+            is_like_android: false,
             default_dwarf_version: 4,
-            linker_is_gnu: true,
             allows_weak_linkage: true,
             has_rpath: false,
             no_default_libraries: true,
@@ -1612,9 +1689,16 @@ impl Default for TargetOptions {
             pre_link_objects_self_contained: Default::default(),
             post_link_objects_self_contained: Default::default(),
             link_self_contained: LinkSelfContainedDefault::False,
+            pre_link_args: LinkArgs::new(),
+            pre_link_args_json: LinkArgsCli::new(),
             late_link_args: LinkArgs::new(),
+            late_link_args_json: LinkArgsCli::new(),
             late_link_args_dynamic: LinkArgs::new(),
+            late_link_args_dynamic_json: LinkArgsCli::new(),
             late_link_args_static: LinkArgs::new(),
+            late_link_args_static_json: LinkArgsCli::new(),
+            post_link_args: LinkArgs::new(),
+            post_link_args_json: LinkArgsCli::new(),
             link_env: cvs![],
             link_env_remove: cvs![],
             archive_format: "gnu".into(),
@@ -2019,13 +2103,13 @@ impl Target {
                     Some(Ok(()))
                 })).unwrap_or(Ok(()))
             } );
-            ($key_name:ident, LinkerFlavor) => ( {
-                let name = (stringify!($key_name)).replace("_", "-");
-                obj.remove(&name).and_then(|o| o.as_str().and_then(|s| {
-                    match LinkerFlavor::from_str(s) {
+            ($key_name:ident = $json_name:expr, LinkerFlavor) => ( {
+                let name = $json_name;
+                obj.remove(name).and_then(|o| o.as_str().and_then(|s| {
+                    match LinkerFlavorCli::from_str(s) {
                         Some(linker_flavor) => base.$key_name = linker_flavor,
                         _ => return Some(Err(format!("'{}' is not a valid value for linker-flavor. \
-                                                      Use {}", s, LinkerFlavor::one_of()))),
+                                                      Use {}", s, LinkerFlavorCli::one_of()))),
                     }
                     Some(Ok(()))
                 })).unwrap_or(Ok(()))
@@ -2106,14 +2190,14 @@ impl Target {
                     base.$key_name = args;
                 }
             } );
-            ($key_name:ident, link_args) => ( {
-                let name = (stringify!($key_name)).replace("_", "-");
-                if let Some(val) = obj.remove(&name) {
+            ($key_name:ident = $json_name:expr, link_args) => ( {
+                let name = $json_name;
+                if let Some(val) = obj.remove(name) {
                     let obj = val.as_object().ok_or_else(|| format!("{}: expected a \
                         JSON object with fields per linker-flavor.", name))?;
-                    let mut args = LinkArgs::new();
+                    let mut args = LinkArgsCli::new();
                     for (k, v) in obj {
-                        let flavor = LinkerFlavor::from_str(&k).ok_or_else(|| {
+                        let flavor = LinkerFlavorCli::from_str(&k).ok_or_else(|| {
                             format!("{}: '{}' is not a valid value for linker-flavor. \
                                      Use 'em', 'gcc', 'ld' or 'msvc'", name, k)
                         })?;
@@ -2199,19 +2283,20 @@ impl Target {
         key!(env);
         key!(abi);
         key!(vendor);
-        key!(linker_flavor, LinkerFlavor)?;
         key!(linker, optional);
+        key!(linker_flavor_json = "linker-flavor", LinkerFlavor)?;
         key!(lld_flavor, LldFlavor)?;
+        key!(linker_is_gnu, bool);
         key!(pre_link_objects = "pre-link-objects", link_objects);
         key!(post_link_objects = "post-link-objects", link_objects);
         key!(pre_link_objects_self_contained = "pre-link-objects-fallback", link_objects);
         key!(post_link_objects_self_contained = "post-link-objects-fallback", link_objects);
         key!(link_self_contained = "crt-objects-fallback", link_self_contained)?;
-        key!(pre_link_args, link_args);
-        key!(late_link_args, link_args);
-        key!(late_link_args_dynamic, link_args);
-        key!(late_link_args_static, link_args);
-        key!(post_link_args, link_args);
+        key!(pre_link_args_json = "pre-link-args", link_args);
+        key!(late_link_args_json = "late-link-args", link_args);
+        key!(late_link_args_dynamic_json = "late-link-args-dynamic", link_args);
+        key!(late_link_args_static_json = "late-link-args-static", link_args);
+        key!(post_link_args_json = "post-link-args", link_args);
         key!(link_script, optional);
         key!(link_env, env);
         key!(link_env_remove, list);
@@ -2238,8 +2323,8 @@ impl Target {
         key!(is_like_windows, bool);
         key!(is_like_msvc, bool);
         key!(is_like_wasm, bool);
+        key!(is_like_android, bool);
         key!(default_dwarf_version, u32);
-        key!(linker_is_gnu, bool);
         key!(allows_weak_linkage, bool);
         key!(has_rpath, bool);
         key!(no_default_libraries, bool);
@@ -2296,6 +2381,8 @@ impl Target {
             // This can cause unfortunate ICEs later down the line.
             return Err("may not set is_builtin for targets not built-in".into());
         }
+        base.update_from_cli();
+
         // Each field should have been read using `Json::remove` so any keys remaining are unused.
         let remaining_keys = obj.keys();
         Ok((
@@ -2311,7 +2398,7 @@ impl Target {
                 load_builtin(target_triple).expect("built-in target")
             }
             TargetTriple::TargetJson { .. } => {
-                panic!("built-in targets doens't support target-paths")
+                panic!("built-in targets doesn't support target-paths")
             }
         }
     }
@@ -2387,42 +2474,44 @@ impl ToJson for Target {
     fn to_json(&self) -> Json {
         let mut d = serde_json::Map::new();
         let default: TargetOptions = Default::default();
+        let mut target = self.clone();
+        target.update_to_cli();
 
         macro_rules! target_val {
             ($attr:ident) => {{
                 let name = (stringify!($attr)).replace("_", "-");
-                d.insert(name, self.$attr.to_json());
+                d.insert(name, target.$attr.to_json());
             }};
         }
 
         macro_rules! target_option_val {
             ($attr:ident) => {{
                 let name = (stringify!($attr)).replace("_", "-");
-                if default.$attr != self.$attr {
-                    d.insert(name, self.$attr.to_json());
+                if default.$attr != target.$attr {
+                    d.insert(name, target.$attr.to_json());
                 }
             }};
-            ($attr:ident, $key_name:expr) => {{
-                let name = $key_name;
-                if default.$attr != self.$attr {
-                    d.insert(name.into(), self.$attr.to_json());
+            ($attr:ident, $json_name:expr) => {{
+                let name = $json_name;
+                if default.$attr != target.$attr {
+                    d.insert(name.into(), target.$attr.to_json());
                 }
             }};
-            (link_args - $attr:ident) => {{
-                let name = (stringify!($attr)).replace("_", "-");
-                if default.$attr != self.$attr {
-                    let obj = self
+            (link_args - $attr:ident, $json_name:expr) => {{
+                let name = $json_name;
+                if default.$attr != target.$attr {
+                    let obj = target
                         .$attr
                         .iter()
                         .map(|(k, v)| (k.desc().to_string(), v.clone()))
                         .collect::<BTreeMap<_, _>>();
-                    d.insert(name, obj.to_json());
+                    d.insert(name.to_string(), obj.to_json());
                 }
             }};
             (env - $attr:ident) => {{
                 let name = (stringify!($attr)).replace("_", "-");
-                if default.$attr != self.$attr {
-                    let obj = self
+                if default.$attr != target.$attr {
+                    let obj = target
                         .$attr
                         .iter()
                         .map(|&(ref k, ref v)| format!("{k}={v}"))
@@ -2444,19 +2533,20 @@ impl ToJson for Target {
         target_option_val!(env);
         target_option_val!(abi);
         target_option_val!(vendor);
-        target_option_val!(linker_flavor);
         target_option_val!(linker);
+        target_option_val!(linker_flavor_json, "linker-flavor");
         target_option_val!(lld_flavor);
+        target_option_val!(linker_is_gnu);
         target_option_val!(pre_link_objects);
         target_option_val!(post_link_objects);
         target_option_val!(pre_link_objects_self_contained, "pre-link-objects-fallback");
         target_option_val!(post_link_objects_self_contained, "post-link-objects-fallback");
         target_option_val!(link_self_contained, "crt-objects-fallback");
-        target_option_val!(link_args - pre_link_args);
-        target_option_val!(link_args - late_link_args);
-        target_option_val!(link_args - late_link_args_dynamic);
-        target_option_val!(link_args - late_link_args_static);
-        target_option_val!(link_args - post_link_args);
+        target_option_val!(link_args - pre_link_args_json, "pre-link-args");
+        target_option_val!(link_args - late_link_args_json, "late-link-args");
+        target_option_val!(link_args - late_link_args_dynamic_json, "late-link-args-dynamic");
+        target_option_val!(link_args - late_link_args_static_json, "late-link-args-static");
+        target_option_val!(link_args - post_link_args_json, "post-link-args");
         target_option_val!(link_script);
         target_option_val!(env - link_env);
         target_option_val!(link_env_remove);
@@ -2484,8 +2574,8 @@ impl ToJson for Target {
         target_option_val!(is_like_windows);
         target_option_val!(is_like_msvc);
         target_option_val!(is_like_wasm);
+        target_option_val!(is_like_android);
         target_option_val!(default_dwarf_version);
-        target_option_val!(linker_is_gnu);
         target_option_val!(allows_weak_linkage);
         target_option_val!(has_rpath);
         target_option_val!(no_default_libraries);
diff --git a/compiler/rustc_target/src/spec/nvptx64_nvidia_cuda.rs b/compiler/rustc_target/src/spec/nvptx64_nvidia_cuda.rs
index 1c5b68001b95..6ab3a8b7eb5a 100644
--- a/compiler/rustc_target/src/spec/nvptx64_nvidia_cuda.rs
+++ b/compiler/rustc_target/src/spec/nvptx64_nvidia_cuda.rs
@@ -10,7 +10,7 @@ pub fn target() -> Target {
         options: TargetOptions {
             os: "cuda".into(),
             vendor: "nvidia".into(),
-            linker_flavor: LinkerFlavor::PtxLinker,
+            linker_flavor: LinkerFlavor::Ptx,
             // The linker can be installed from `crates.io`.
             linker: Some("rust-ptx-linker".into()),
             linker_is_gnu: false,
diff --git a/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs
index 5413c4f33ff6..1cb9ce40cb1e 100644
--- a/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs
@@ -1,5 +1,5 @@
 use crate::abi::Endian;
-use crate::spec::{LinkerFlavor, RelroLevel, Target, TargetOptions};
+use crate::spec::{LinkerFlavor, Target, TargetOptions};
 
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
@@ -7,10 +7,6 @@ pub fn target() -> Target {
     base.add_pre_link_args(LinkerFlavor::Gcc, &["-m64"]);
     base.max_atomic_width = Some(64);
 
-    // ld.so in at least RHEL6 on ppc64 has a bug related to BIND_NOW, so only enable partial RELRO
-    // for now. https://github.com/rust-lang/rust/pull/43170#issuecomment-315411474
-    base.relro_level = RelroLevel::Partial;
-
     Target {
         llvm_target: "powerpc64-unknown-linux-gnu".into(),
         pointer_width: 64,
diff --git a/compiler/rustc_target/src/spec/powerpc_unknown_freebsd.rs b/compiler/rustc_target/src/spec/powerpc_unknown_freebsd.rs
index 516b2de37eaa..75ac66c276d5 100644
--- a/compiler/rustc_target/src/spec/powerpc_unknown_freebsd.rs
+++ b/compiler/rustc_target/src/spec/powerpc_unknown_freebsd.rs
@@ -1,5 +1,5 @@
 use crate::abi::Endian;
-use crate::spec::{LinkerFlavor, RelocModel, Target, TargetOptions};
+use crate::spec::{LinkerFlavor, Target, TargetOptions};
 
 pub fn target() -> Target {
     let mut base = super::freebsd_base::opts();
@@ -15,7 +15,6 @@ pub fn target() -> Target {
         options: TargetOptions {
             endian: Endian::Big,
             features: "+secure-plt".into(),
-            relocation_model: RelocModel::Pic,
             mcount: "_mcount".into(),
             ..base
         },
diff --git a/compiler/rustc_target/src/spec/tests/tests_impl.rs b/compiler/rustc_target/src/spec/tests/tests_impl.rs
index 03e579aee0a9..0af599916a99 100644
--- a/compiler/rustc_target/src/spec/tests/tests_impl.rs
+++ b/compiler/rustc_target/src/spec/tests/tests_impl.rs
@@ -2,28 +2,31 @@ use super::super::*;
 use std::assert_matches::assert_matches;
 
 // Test target self-consistency and JSON encoding/decoding roundtrip.
-pub(super) fn test_target(target: Target) {
-    target.check_consistency();
-    assert_eq!(Target::from_json(target.to_json()).map(|(j, _)| j), Ok(target));
+pub(super) fn test_target(mut target: Target, triple: &str) {
+    let recycled_target = Target::from_json(target.to_json()).map(|(j, _)| j);
+    target.update_to_cli();
+    target.check_consistency(triple);
+    assert_eq!(recycled_target, Ok(target));
 }
 
 impl Target {
-    fn check_consistency(&self) {
+    fn check_consistency(&self, triple: &str) {
         assert_eq!(self.is_like_osx, self.vendor == "apple");
         assert_eq!(self.is_like_solaris, self.os == "solaris" || self.os == "illumos");
         assert_eq!(self.is_like_windows, self.os == "windows" || self.os == "uefi");
         assert_eq!(self.is_like_wasm, self.arch == "wasm32" || self.arch == "wasm64");
-        assert!(self.is_like_windows || !self.is_like_msvc);
+        if self.is_like_msvc {
+            assert!(self.is_like_windows);
+        }
 
         // Check that default linker flavor and lld flavor are compatible
         // with some other key properties.
         assert_eq!(self.is_like_osx, matches!(self.lld_flavor, LldFlavor::Ld64));
         assert_eq!(self.is_like_msvc, matches!(self.lld_flavor, LldFlavor::Link));
         assert_eq!(self.is_like_wasm, matches!(self.lld_flavor, LldFlavor::Wasm));
-        assert_eq!(self.os == "l4re", matches!(self.linker_flavor, LinkerFlavor::L4Bender));
-        assert_eq!(self.os == "emscripten", matches!(self.linker_flavor, LinkerFlavor::Em));
-        assert_eq!(self.arch == "bpf", matches!(self.linker_flavor, LinkerFlavor::BpfLinker));
-        assert_eq!(self.arch == "nvptx64", matches!(self.linker_flavor, LinkerFlavor::PtxLinker));
+        assert_eq!(self.os == "emscripten", matches!(self.linker_flavor, LinkerFlavor::EmCc));
+        assert_eq!(self.arch == "bpf", matches!(self.linker_flavor, LinkerFlavor::Bpf));
+        assert_eq!(self.arch == "nvptx64", matches!(self.linker_flavor, LinkerFlavor::Ptx));
 
         for args in [
             &self.pre_link_args,
@@ -63,17 +66,14 @@ impl Target {
                             LinkerFlavor::Lld(LldFlavor::Wasm) | LinkerFlavor::Gcc
                         )
                     }
-                    (LinkerFlavor::L4Bender, LldFlavor::Ld) => {
-                        assert_matches!(flavor, LinkerFlavor::L4Bender)
+                    (LinkerFlavor::EmCc, LldFlavor::Wasm) => {
+                        assert_matches!(flavor, LinkerFlavor::EmCc)
                     }
-                    (LinkerFlavor::Em, LldFlavor::Wasm) => {
-                        assert_matches!(flavor, LinkerFlavor::Em)
+                    (LinkerFlavor::Bpf, LldFlavor::Ld) => {
+                        assert_matches!(flavor, LinkerFlavor::Bpf)
                     }
-                    (LinkerFlavor::BpfLinker, LldFlavor::Ld) => {
-                        assert_matches!(flavor, LinkerFlavor::BpfLinker)
-                    }
-                    (LinkerFlavor::PtxLinker, LldFlavor::Ld) => {
-                        assert_matches!(flavor, LinkerFlavor::PtxLinker)
+                    (LinkerFlavor::Ptx, LldFlavor::Ld) => {
+                        assert_matches!(flavor, LinkerFlavor::Ptx)
                     }
                     flavors => unreachable!("unexpected flavor combination: {:?}", flavors),
                 }
@@ -94,8 +94,9 @@ impl Target {
                             check_noncc(LinkerFlavor::Ld);
                             check_noncc(LinkerFlavor::Lld(LldFlavor::Ld));
                         }
+                        LldFlavor::Ld64 => check_noncc(LinkerFlavor::Lld(LldFlavor::Ld64)),
                         LldFlavor::Wasm => check_noncc(LinkerFlavor::Lld(LldFlavor::Wasm)),
-                        LldFlavor::Ld64 | LldFlavor::Link => {}
+                        LldFlavor::Link => {}
                     },
                     _ => {}
                 }
@@ -109,20 +110,57 @@ impl Target {
             );
         }
 
-        assert!(
-            (self.pre_link_objects_self_contained.is_empty()
-                && self.post_link_objects_self_contained.is_empty())
-                || self.link_self_contained != LinkSelfContainedDefault::False
-        );
+        if self.link_self_contained == LinkSelfContainedDefault::False {
+            assert!(
+                self.pre_link_objects_self_contained.is_empty()
+                    && self.post_link_objects_self_contained.is_empty()
+            );
+        }
 
         // If your target really needs to deviate from the rules below,
         // except it and document the reasons.
         // Keep the default "unknown" vendor instead.
         assert_ne!(self.vendor, "");
+        assert_ne!(self.os, "");
         if !self.can_use_os_unknown() {
             // Keep the default "none" for bare metal targets instead.
             assert_ne!(self.os, "unknown");
         }
+
+        // Check dynamic linking stuff
+        // BPF: when targeting user space vms (like rbpf), those can load dynamic libraries.
+        if self.os == "none" && self.arch != "bpf" {
+            assert!(!self.dynamic_linking);
+        }
+        if self.only_cdylib
+            || self.crt_static_allows_dylibs
+            || !self.late_link_args_dynamic.is_empty()
+        {
+            assert!(self.dynamic_linking);
+        }
+        // Apparently PIC was slow on wasm at some point, see comments in wasm_base.rs
+        if self.dynamic_linking && !(self.is_like_wasm && self.os != "emscripten") {
+            assert_eq!(self.relocation_model, RelocModel::Pic);
+        }
+        // PIEs are supported but not enabled by default with linuxkernel target.
+        if self.position_independent_executables && !triple.ends_with("-linuxkernel") {
+            assert_eq!(self.relocation_model, RelocModel::Pic);
+        }
+        // The UEFI targets do not support dynamic linking but still require PIC (#101377).
+        if self.relocation_model == RelocModel::Pic && self.os != "uefi" {
+            assert!(self.dynamic_linking || self.position_independent_executables);
+        }
+        if self.static_position_independent_executables {
+            assert!(self.position_independent_executables);
+        }
+        if self.position_independent_executables {
+            assert!(self.executables);
+        }
+
+        // Check crt static stuff
+        if self.crt_static_default || self.crt_static_allows_dylibs {
+            assert!(self.crt_static_respected);
+        }
     }
 
     // Add your target to the whitelist if it has `std` library
diff --git a/compiler/rustc_target/src/spec/thumbv5te_none_eabi.rs b/compiler/rustc_target/src/spec/thumbv5te_none_eabi.rs
new file mode 100644
index 000000000000..021b0e0eb622
--- /dev/null
+++ b/compiler/rustc_target/src/spec/thumbv5te_none_eabi.rs
@@ -0,0 +1,41 @@
+//! Targets the ARMv5TE, with code as `t32` code by default.
+
+use crate::spec::{cvs, FramePointer, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "thumbv5te-none-eabi".into(),
+        pointer_width: 32,
+        arch: "arm".into(),
+        /* Data layout args are '-' separated:
+         * little endian
+         * stack is 64-bit aligned (EABI)
+         * pointers are 32-bit
+         * i64 must be 64-bit aligned (EABI)
+         * mangle names with ELF style
+         * native integers are 32-bit
+         * All other elements are default
+         */
+        data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".into(),
+
+        options: TargetOptions {
+            abi: "eabi".into(),
+            // extra args passed to the external assembler (assuming `arm-none-eabi-as`):
+            // * activate t32/a32 interworking
+            // * use arch ARMv5TE
+            // * use little-endian
+            asm_args: cvs!["-mthumb-interwork", "-march=armv5te", "-mlittle-endian",],
+            // minimum extra features, these cannot be disabled via -C
+            // Also force-enable 32-bit atomics, which allows the use of atomic load/store only.
+            // The resulting atomics are ABI incompatible with atomics backed by libatomic.
+            features: "+soft-float,+strict-align,+atomics-32".into(),
+            frame_pointer: FramePointer::MayOmit,
+            main_needs_argc_argv: false,
+            // don't have atomic compare-and-swap
+            atomic_cas: false,
+            has_thumb_interworking: true,
+
+            ..super::thumb_base::opts()
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/spec/uefi_msvc_base.rs b/compiler/rustc_target/src/spec/uefi_msvc_base.rs
index aee8eb2e31c7..99af7d85e1d0 100644
--- a/compiler/rustc_target/src/spec/uefi_msvc_base.rs
+++ b/compiler/rustc_target/src/spec/uefi_msvc_base.rs
@@ -9,7 +9,8 @@
 // the timer-interrupt. Device-drivers are required to use polling-based models. Furthermore, all
 // code runs in the same environment, no process separation is supported.
 
-use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, StackProbeType, TargetOptions};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy};
+use crate::spec::{StackProbeType, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let mut base = super::msvc_base::opts();
diff --git a/compiler/rustc_target/src/spec/wasm32_unknown_emscripten.rs b/compiler/rustc_target/src/spec/wasm32_unknown_emscripten.rs
index c7e7d2210865..6f77ef98c015 100644
--- a/compiler/rustc_target/src/spec/wasm32_unknown_emscripten.rs
+++ b/compiler/rustc_target/src/spec/wasm32_unknown_emscripten.rs
@@ -5,13 +5,13 @@ pub fn target() -> Target {
     // Reset flags for non-Em flavors back to empty to satisfy sanity checking tests.
     let pre_link_args = LinkArgs::new();
     let post_link_args = TargetOptions::link_args(
-        LinkerFlavor::Em,
+        LinkerFlavor::EmCc,
         &["-sABORTING_MALLOC=0", "-Wl,--fatal-warnings"],
     );
 
     let opts = TargetOptions {
         os: "emscripten".into(),
-        linker_flavor: LinkerFlavor::Em,
+        linker_flavor: LinkerFlavor::EmCc,
         // emcc emits two files - a .js file to instantiate the wasm and supply platform
         // functionality, and a .wasm file.
         exe_suffix: ".js".into(),
diff --git a/compiler/rustc_target/src/spec/windows_gnullvm_base.rs b/compiler/rustc_target/src/spec/windows_gnullvm_base.rs
index bae007dc9f3b..f30be25497d8 100644
--- a/compiler/rustc_target/src/spec/windows_gnullvm_base.rs
+++ b/compiler/rustc_target/src/spec/windows_gnullvm_base.rs
@@ -3,7 +3,7 @@ use crate::spec::{cvs, LinkerFlavor, TargetOptions};
 pub fn opts() -> TargetOptions {
     // We cannot use `-nodefaultlibs` because compiler-rt has to be passed
     // as a path since it's not added to linker search path by the default.
-    // There were attemts to make it behave like libgcc (so one can just use -l<name>)
+    // There were attempts to make it behave like libgcc (so one can just use -l<name>)
     // but LLVM maintainers rejected it: https://reviews.llvm.org/D51440
     let pre_link_args =
         TargetOptions::link_args(LinkerFlavor::Gcc, &["-nolibc", "--unwindlib=none"]);
diff --git a/compiler/rustc_target/src/spec/x86_64_unknown_l4re_uclibc.rs b/compiler/rustc_target/src/spec/x86_64_unknown_l4re_uclibc.rs
index 78189a0c0969..26da7e800114 100644
--- a/compiler/rustc_target/src/spec/x86_64_unknown_l4re_uclibc.rs
+++ b/compiler/rustc_target/src/spec/x86_64_unknown_l4re_uclibc.rs
@@ -4,8 +4,6 @@ pub fn target() -> Target {
     let mut base = super::l4re_base::opts();
     base.cpu = "x86-64".into();
     base.max_atomic_width = Some(64);
-    base.crt_static_allows_dylibs = false;
-    base.dynamic_linking = false;
     base.panic_strategy = PanicStrategy::Abort;
 
     Target {
diff --git a/compiler/rustc_target/src/spec/x86_64_unknown_none.rs b/compiler/rustc_target/src/spec/x86_64_unknown_none.rs
index 809fd642d411..b9a345127e37 100644
--- a/compiler/rustc_target/src/spec/x86_64_unknown_none.rs
+++ b/compiler/rustc_target/src/spec/x86_64_unknown_none.rs
@@ -4,10 +4,8 @@
 // `target-cpu` compiler flags to opt-in more hardware-specific
 // features.
 
-use super::{
-    CodeModel, LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, RelroLevel, StackProbeType,
-    Target, TargetOptions,
-};
+use super::{CodeModel, LinkerFlavor, LldFlavor, PanicStrategy};
+use super::{RelroLevel, StackProbeType, Target, TargetOptions};
 
 pub fn target() -> Target {
     let opts = TargetOptions {
@@ -18,7 +16,6 @@ pub fn target() -> Target {
         position_independent_executables: true,
         static_position_independent_executables: true,
         relro_level: RelroLevel::Full,
-        relocation_model: RelocModel::Pic,
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".into()),
         features:
diff --git a/compiler/rustc_trait_selection/src/autoderef.rs b/compiler/rustc_trait_selection/src/autoderef.rs
index 8b7e8984a8ad..36ab8f3bd884 100644
--- a/compiler/rustc_trait_selection/src/autoderef.rs
+++ b/compiler/rustc_trait_selection/src/autoderef.rs
@@ -1,6 +1,6 @@
+use crate::errors::AutoDerefReachedRecursionLimit;
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::{self, TraitEngine};
-use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_infer::infer::InferCtxt;
 use rustc_middle::ty::{self, TraitRef, Ty, TyCtxt};
@@ -222,19 +222,10 @@ pub fn report_autoderef_recursion_limit_error<'tcx>(tcx: TyCtxt<'tcx>, span: Spa
         Limit(0) => Limit(2),
         limit => limit * 2,
     };
-    struct_span_err!(
-        tcx.sess,
+    tcx.sess.emit_err(AutoDerefReachedRecursionLimit {
         span,
-        E0055,
-        "reached the recursion limit while auto-dereferencing `{:?}`",
-        ty
-    )
-    .span_label(span, "deref recursion limit reached")
-    .help(&format!(
-        "consider increasing the recursion limit by adding a \
-             `#![recursion_limit = \"{}\"]` attribute to your crate (`{}`)",
+        ty,
         suggested_limit,
-        tcx.crate_name(LOCAL_CRATE),
-    ))
-    .emit();
+        crate_name: tcx.crate_name(LOCAL_CRATE),
+    });
 }
diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs
new file mode 100644
index 000000000000..617934685949
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/errors.rs
@@ -0,0 +1,102 @@
+use rustc_errors::{fluent, ErrorGuaranteed, Handler, IntoDiagnostic};
+use rustc_macros::Diagnostic;
+use rustc_middle::ty::{self, PolyTraitRef, Ty};
+use rustc_session::Limit;
+use rustc_span::{Span, Symbol};
+
+#[derive(Diagnostic)]
+#[diag(trait_selection::dump_vtable_entries)]
+pub struct DumpVTableEntries<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_ref: PolyTraitRef<'a>,
+    pub entries: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(trait_selection::unable_to_construct_constant_value)]
+pub struct UnableToConstructConstantValue<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub unevaluated: ty::UnevaluatedConst<'a>,
+}
+
+#[derive(Diagnostic)]
+#[help]
+#[diag(trait_selection::auto_deref_reached_recursion_limit, code = "E0055")]
+pub struct AutoDerefReachedRecursionLimit<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub ty: Ty<'a>,
+    pub suggested_limit: Limit,
+    pub crate_name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(trait_selection::empty_on_clause_in_rustc_on_unimplemented, code = "E0232")]
+pub struct EmptyOnClauseInOnUnimplemented {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(trait_selection::invalid_on_clause_in_rustc_on_unimplemented, code = "E0232")]
+pub struct InvalidOnClauseInOnUnimplemented {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(trait_selection::no_value_in_rustc_on_unimplemented, code = "E0232")]
+#[note]
+pub struct NoValueInOnUnimplemented {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+pub struct NegativePositiveConflict<'a> {
+    pub impl_span: Span,
+    pub trait_desc: &'a str,
+    pub self_desc: &'a Option<String>,
+    pub negative_impl_span: Result<Span, Symbol>,
+    pub positive_impl_span: Result<Span, Symbol>,
+}
+
+impl IntoDiagnostic<'_> for NegativePositiveConflict<'_> {
+    fn into_diagnostic(
+        self,
+        handler: &Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(fluent::trait_selection::negative_positive_conflict);
+        diag.set_arg("trait_desc", self.trait_desc);
+        diag.set_arg(
+            "self_desc",
+            self.self_desc.clone().map_or_else(|| String::from("none"), |ty| ty),
+        );
+        diag.set_span(self.impl_span);
+        diag.code(rustc_errors::error_code!(E0751));
+        match self.negative_impl_span {
+            Ok(span) => {
+                diag.span_label(span, fluent::trait_selection::negative_implementation_here);
+            }
+            Err(cname) => {
+                diag.note(fluent::trait_selection::negative_implementation_in_crate);
+                diag.set_arg("negative_impl_cname", cname.to_string());
+            }
+        }
+        match self.positive_impl_span {
+            Ok(span) => {
+                diag.span_label(span, fluent::trait_selection::positive_implementation_here);
+            }
+            Err(cname) => {
+                diag.note(fluent::trait_selection::positive_implementation_in_crate);
+                diag.set_arg("positive_impl_cname", cname.to_string());
+            }
+        }
+        diag
+    }
+}
diff --git a/compiler/rustc_trait_selection/src/infer.rs b/compiler/rustc_trait_selection/src/infer.rs
index 9d30374f8b8a..ba403ab2da2b 100644
--- a/compiler/rustc_trait_selection/src/infer.rs
+++ b/compiler/rustc_trait_selection/src/infer.rs
@@ -24,6 +24,13 @@ pub trait InferCtxtExt<'tcx> {
         span: Span,
     ) -> bool;
 
+    fn type_is_sized_modulo_regions(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        ty: Ty<'tcx>,
+        span: Span,
+    ) -> bool;
+
     fn partially_normalize_associated_types_in<T>(
         &self,
         cause: ObligationCause<'tcx>,
@@ -74,6 +81,16 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'cx, 'tcx> {
         traits::type_known_to_meet_bound_modulo_regions(self, param_env, ty, copy_def_id, span)
     }
 
+    fn type_is_sized_modulo_regions(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        ty: Ty<'tcx>,
+        span: Span,
+    ) -> bool {
+        let lang_item = self.tcx.require_lang_item(LangItem::Sized, None);
+        traits::type_known_to_meet_bound_modulo_regions(self, param_env, ty, lang_item, span)
+    }
+
     /// Normalizes associated types in `value`, potentially returning
     /// new obligations that must further be processed.
     fn partially_normalize_associated_types_in<T>(
diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
index 77cc2c164c34..5d52aa075230 100644
--- a/compiler/rustc_trait_selection/src/lib.rs
+++ b/compiler/rustc_trait_selection/src/lib.rs
@@ -16,9 +16,7 @@
 #![feature(control_flow_enum)]
 #![feature(drain_filter)]
 #![feature(hash_drain_filter)]
-#![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(if_let_guard)]
 #![feature(never_type)]
 #![feature(type_alias_impl_trait)]
@@ -37,5 +35,6 @@ extern crate rustc_middle;
 extern crate smallvec;
 
 pub mod autoderef;
+pub mod errors;
 pub mod infer;
 pub mod traits;
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index 4bab99355012..6ed4f1b8c498 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -3,13 +3,14 @@
 
 use super::*;
 
+use crate::errors::UnableToConstructConstantValue;
 use crate::infer::region_constraints::{Constraint, RegionConstraintData};
 use crate::infer::InferCtxt;
 use crate::traits::project::ProjectAndUnifyResult;
 use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::visit::TypeVisitable;
-use rustc_middle::ty::{Region, RegionVid, Term};
+use rustc_middle::ty::{Region, RegionVid};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 
@@ -611,7 +612,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
     }
 
     fn is_self_referential_projection(&self, p: ty::PolyProjectionPredicate<'_>) -> bool {
-        if let Term::Ty(ty) = p.term().skip_binder() {
+        if let Some(ty) = p.term().skip_binder().ty() {
             matches!(ty.kind(), ty::Projection(proj) if proj == &p.skip_binder().projection_ty)
         } else {
             false
@@ -830,8 +831,11 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                                 Ok(None) => {
                                     let tcx = self.tcx;
                                     let def_id = unevaluated.def.did;
-                                    let reported = tcx.sess.struct_span_err(tcx.def_span(def_id), &format!("unable to construct a constant value for the unevaluated constant {:?}", unevaluated)).emit();
-
+                                    let reported =
+                                        tcx.sess.emit_err(UnableToConstructConstantValue {
+                                            span: tcx.def_span(def_id),
+                                            unevaluated: unevaluated,
+                                        });
                                     Err(ErrorHandled::Reported(reported))
                                 }
                                 Err(err) => Err(err),
diff --git a/compiler/rustc_trait_selection/src/traits/codegen.rs b/compiler/rustc_trait_selection/src/traits/codegen.rs
index c0700748c79f..0155798c8b6d 100644
--- a/compiler/rustc_trait_selection/src/traits/codegen.rs
+++ b/compiler/rustc_trait_selection/src/traits/codegen.rs
@@ -4,10 +4,12 @@
 // general routines.
 
 use crate::infer::{DefiningAnchor, TyCtxtInferExt};
+use crate::traits::error_reporting::InferCtxtExt;
 use crate::traits::{
     ImplSource, Obligation, ObligationCause, SelectionContext, TraitEngine, TraitEngineExt,
     Unimplemented,
 };
+use rustc_infer::traits::FulfillmentErrorCode;
 use rustc_middle::traits::CodegenObligationError;
 use rustc_middle::ty::{self, TyCtxt};
 
@@ -18,8 +20,7 @@ use rustc_middle::ty::{self, TyCtxt};
 /// obligations *could be* resolved if we wanted to.
 ///
 /// This also expects that `trait_ref` is fully normalized.
-#[instrument(level = "debug", skip(tcx))]
-pub fn codegen_fulfill_obligation<'tcx>(
+pub fn codegen_select_candidate<'tcx>(
     tcx: TyCtxt<'tcx>,
     (param_env, trait_ref): (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>),
 ) -> Result<&'tcx ImplSource<'tcx, ()>, CodegenObligationError> {
@@ -63,6 +64,14 @@ pub fn codegen_fulfill_obligation<'tcx>(
         // optimization to stop iterating early.
         let errors = fulfill_cx.select_all_or_error(&infcx);
         if !errors.is_empty() {
+            // `rustc_monomorphize::collector` assumes there are no type errors.
+            // Cycle errors are the only post-monomorphization errors possible; emit them now so
+            // `rustc_ty_utils::resolve_associated_item` doesn't return `None` post-monomorphization.
+            for err in errors {
+                if let FulfillmentErrorCode::CodeCycle(cycle) = err.code {
+                    infcx.report_overflow_error_cycle(&cycle);
+                }
+            }
             return Err(CodegenObligationError::FulfillmentError);
         }
 
@@ -74,7 +83,6 @@ pub fn codegen_fulfill_obligation<'tcx>(
         // (ouz-a) This is required for `type-alias-impl-trait/assoc-projection-ice.rs` to pass
         let _ = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
 
-        debug!("Cache miss: {trait_ref:?} => {impl_source:?}");
         Ok(&*tcx.arena.alloc(impl_source))
     })
 }
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index 292787d4dbb2..94de8abce192 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -22,7 +22,6 @@ use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::util;
 use rustc_middle::traits::specialization_graph::OverlapMode;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, ImplSubject, Ty, TyCtxt, TypeVisitor};
 use rustc_span::symbol::sym;
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index 254bc4ab6638..dc585fca34f8 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -138,7 +138,7 @@ impl<'tcx> ConstUnifyCtxt<'tcx> {
 #[instrument(skip(tcx), level = "debug")]
 pub fn try_unify_abstract_consts<'tcx>(
     tcx: TyCtxt<'tcx>,
-    (a, b): (ty::Unevaluated<'tcx, ()>, ty::Unevaluated<'tcx, ()>),
+    (a, b): (ty::UnevaluatedConst<'tcx>, ty::UnevaluatedConst<'tcx>),
     param_env: ty::ParamEnv<'tcx>,
 ) -> bool {
     (|| {
@@ -161,7 +161,7 @@ pub fn try_unify_abstract_consts<'tcx>(
 #[instrument(skip(infcx), level = "debug")]
 pub fn is_const_evaluatable<'cx, 'tcx>(
     infcx: &InferCtxt<'cx, 'tcx>,
-    uv: ty::Unevaluated<'tcx, ()>,
+    uv: ty::UnevaluatedConst<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     span: Span,
 ) -> Result<(), NotConstEvaluatable> {
@@ -183,7 +183,7 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
                 FailureKind::Concrete => {}
             }
         }
-        let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span));
+        let concrete = infcx.const_eval_resolve(param_env, uv, Some(span));
         match concrete {
             Err(ErrorHandled::TooGeneric) => {
                 Err(NotConstEvaluatable::Error(infcx.tcx.sess.delay_span_bug(
@@ -210,7 +210,7 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
         // and hopefully soon change this to an error.
         //
         // See #74595 for more details about this.
-        let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span));
+        let concrete = infcx.const_eval_resolve(param_env, uv, Some(span));
 
         match concrete {
           // If we're evaluating a foreign constant, under a nightly compiler without generic
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index e4af7022239b..b0cabc6275f5 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -349,7 +349,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             message,
                             label,
                             note,
-                            enclosing_scope,
+                            parent_label,
                             append_const_msg,
                         } = self.on_unimplemented_note(trait_ref, &obligation);
                         let have_alt_message = message.is_some() || label.is_some();
@@ -450,12 +450,27 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                         {
                             "consider using `()`, or a `Result`".to_owned()
                         } else {
-                            format!(
-                                "{}the trait `{}` is not implemented for `{}`",
-                                pre_message,
-                                trait_predicate.print_modifiers_and_trait_path(),
-                                trait_ref.skip_binder().self_ty(),
-                            )
+                            let ty_desc = match trait_ref.skip_binder().self_ty().kind() {
+                                ty::FnDef(_, _) => Some("fn item"),
+                                ty::Closure(_, _) => Some("closure"),
+                                _ => None,
+                            };
+
+                            match ty_desc {
+                                Some(desc) => format!(
+                                    "{}the trait `{}` is not implemented for {} `{}`",
+                                    pre_message,
+                                    trait_predicate.print_modifiers_and_trait_path(),
+                                    desc,
+                                    trait_ref.skip_binder().self_ty(),
+                                ),
+                                None => format!(
+                                    "{}the trait `{}` is not implemented for `{}`",
+                                    pre_message,
+                                    trait_predicate.print_modifiers_and_trait_path(),
+                                    trait_ref.skip_binder().self_ty(),
+                                ),
+                            }
                         };
 
                         if self.suggest_add_reference_to_arg(
@@ -515,7 +530,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                             // If it has a custom `#[rustc_on_unimplemented]` note, let's display it
                             err.note(s.as_str());
                         }
-                        if let Some(ref s) = enclosing_scope {
+                        if let Some(ref s) = parent_label {
                             let body = tcx
                                 .hir()
                                 .opt_local_def_id(obligation.cause.body_id)
@@ -524,11 +539,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                                         hir_id: obligation.cause.body_id,
                                     })
                                 });
-
-                            let enclosing_scope_span =
-                                tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(body));
-
-                            err.span_label(enclosing_scope_span, s);
+                            err.span_label(tcx.def_span(body), s);
                         }
 
                         self.suggest_floating_point_literal(&obligation, &mut err, &trait_ref);
@@ -1529,6 +1540,9 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                 }
                 diag.emit();
             }
+            FulfillmentErrorCode::CodeCycle(ref cycle) => {
+                self.report_overflow_error_cycle(cycle);
+            }
         }
     }
 
@@ -1805,13 +1819,21 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                 return false;
             }
             if candidates.len() == 1 {
+                let ty_desc = match candidates[0].self_ty().kind() {
+                    ty::FnPtr(_) => Some("fn pointer"),
+                    _ => None,
+                };
+                let the_desc = match ty_desc {
+                    Some(desc) => format!(" implemented for {} `", desc),
+                    None => " implemented for `".to_string(),
+                };
                 err.highlighted_help(vec![
                     (
                         format!("the trait `{}` ", candidates[0].print_only_trait_path()),
                         Style::NoStyle,
                     ),
                     ("is".to_string(), Style::Highlight),
-                    (" implemented for `".to_string(), Style::NoStyle),
+                    (the_desc, Style::NoStyle),
                     (candidates[0].self_ty().to_string(), Style::Highlight),
                     ("`".to_string(), Style::NoStyle),
                 ]);
@@ -1878,7 +1900,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                         // types, too.
                         self.tcx
                             .visibility(def.did())
-                            .is_accessible_from(body_id.owner.to_def_id(), self.tcx)
+                            .is_accessible_from(body_id.owner.def_id, self.tcx)
                     } else {
                         true
                     }
@@ -2014,7 +2036,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
         let predicate = self.resolve_vars_if_possible(obligation.predicate);
         let span = obligation.cause.span;
 
-        debug!(?predicate, obligation.cause.code = tracing::field::debug(&obligation.cause.code()));
+        debug!(?predicate, obligation.cause.code = ?obligation.cause.code());
 
         // Ambiguity errors are often caused as fallout from earlier errors.
         // We ignore them if this `infcx` is tainted in some cases below.
@@ -2191,12 +2213,12 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                         && let [
                             ..,
                             trait_path_segment @ hir::PathSegment {
-                                res: Some(rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id)),
+                                res: rustc_hir::def::Res::Def(rustc_hir::def::DefKind::Trait, trait_id),
                                 ..
                             },
                             hir::PathSegment {
                                 ident: assoc_item_name,
-                                res: Some(rustc_hir::def::Res::Def(_, item_id)),
+                                res: rustc_hir::def::Res::Def(_, item_id),
                                 ..
                             }
                         ] = path.segments
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
index 6b03555bc698..07e470dc2ae5 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
@@ -4,7 +4,7 @@ use super::{
 use crate::infer::InferCtxt;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::subst::{Subst, SubstsRef};
+use rustc_middle::ty::SubstsRef;
 use rustc_middle::ty::{self, GenericParamDefKind};
 use rustc_span::symbol::sym;
 use std::iter;
@@ -256,7 +256,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     }
                 }
             }
-            if let ty::Dynamic(traits, _) = self_ty.kind() {
+            if let ty::Dynamic(traits, _, _) = self_ty.kind() {
                 for t in traits.iter() {
                     if let ty::ExistentialPredicate::Trait(trait_ref) = t.skip_binder() {
                         flags.push((sym::_Self, Some(self.tcx.def_path_str(trait_ref.def_id))))
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 02adae5bde15..fff26547be07 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -25,8 +25,7 @@ use rustc_middle::hir::map;
 use rustc_middle::ty::{
     self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree,
     GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, IsSuggestable,
-    ProjectionPredicate, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
-    TypeVisitable,
+    ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable,
 };
 use rustc_middle::ty::{TypeAndMut, TypeckResults};
 use rustc_session::Limit;
@@ -174,7 +173,7 @@ pub trait InferCtxtExt<'tcx> {
         &self,
         err: &mut Diagnostic,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
-        proj_pred: Option<ty::PolyProjectionPredicate<'tcx>>,
+        associated_item: Option<(&'static str, Ty<'tcx>)>,
         body_id: hir::HirId,
     );
 
@@ -467,7 +466,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         &self,
         mut err: &mut Diagnostic,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
-        proj_pred: Option<ty::PolyProjectionPredicate<'tcx>>,
+        associated_ty: Option<(&'static str, Ty<'tcx>)>,
         body_id: hir::HirId,
     ) {
         let trait_pred = self.resolve_numeric_literals_with_default(trait_pred);
@@ -604,21 +603,18 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                         trait_pred.print_modifiers_and_trait_path().to_string()
                     );
 
-                    if let Some(proj_pred) = proj_pred {
-                        let ProjectionPredicate { projection_ty, term } = proj_pred.skip_binder();
-                        let item = self.tcx.associated_item(projection_ty.item_def_id);
-
+                    if let Some((name, term)) = associated_ty {
                         // FIXME: this case overlaps with code in TyCtxt::note_and_explain_type_err.
                         // That should be extracted into a helper function.
                         if constraint.ends_with('>') {
                             constraint = format!(
-                                "{}, {}={}>",
+                                "{}, {} = {}>",
                                 &constraint[..constraint.len() - 1],
-                                item.name,
+                                name,
                                 term
                             );
                         } else {
-                            constraint.push_str(&format!("<{}={}>", item.name, term));
+                            constraint.push_str(&format!("<{} = {}>", name, term));
                         }
                     }
 
@@ -648,7 +644,13 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     ..
                 }) if !param_ty => {
                     // Missing generic type parameter bound.
-                    if suggest_arbitrary_trait_bound(self.tcx, generics, &mut err, trait_pred) {
+                    if suggest_arbitrary_trait_bound(
+                        self.tcx,
+                        generics,
+                        &mut err,
+                        trait_pred,
+                        associated_ty,
+                    ) {
                         return;
                     }
                 }
@@ -657,7 +659,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                 _ => {}
             }
 
-            hir_id = self.tcx.hir().local_def_id_to_hir_id(self.tcx.hir().get_parent_item(hir_id));
+            hir_id = self.tcx.hir().get_parent_item(hir_id).into();
         }
     }
 
@@ -774,7 +776,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             // Get the local name of this closure. This can be inaccurate because
             // of the possibility of reassignment, but this should be good enough.
             match &kind {
-                hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, ident, None) => {
+                hir::PatKind::Binding(hir::BindingAnnotation::NONE, _, ident, None) => {
                     Some(ident.name)
                 }
                 _ => {
@@ -1065,7 +1067,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         self_ty: Ty<'tcx>,
         object_ty: Ty<'tcx>,
     ) {
-        let ty::Dynamic(predicates, _) = object_ty.kind() else { return; };
+        let ty::Dynamic(predicates, _, ty::Dyn) = object_ty.kind() else { return; };
         let self_ref_ty = self.tcx.mk_imm_ref(self.tcx.lifetimes.re_erased, self_ty);
 
         for predicate in predicates.iter() {
@@ -1158,8 +1160,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     // and if not maybe suggest doing something else? If we kept the expression around we
                     // could also check if it is an fn call (very likely) and suggest changing *that*, if
                     // it is from the local crate.
-                    err.span_suggestion_verbose(
-                        expr.span.shrink_to_hi().with_hi(span.hi()),
+                    err.span_suggestion(
+                        span,
                         "remove the `.await`",
                         "",
                         Applicability::MachineApplicable,
@@ -1363,7 +1365,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         let trait_pred = self.resolve_vars_if_possible(trait_pred);
         let ty = trait_pred.skip_binder().self_ty();
         let is_object_safe = match ty.kind() {
-            ty::Dynamic(predicates, _) => {
+            ty::Dynamic(predicates, _, ty::Dyn) => {
                 // If the `dyn Trait` is not object safe, do not suggest `Box<dyn Trait>`.
                 predicates
                     .principal_def_id()
@@ -1423,7 +1425,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         let mut spans_and_needs_box = vec![];
 
         match liberated_sig.output().kind() {
-            ty::Dynamic(predicates, _) => {
+            ty::Dynamic(predicates, _, _) => {
                 let cause = ObligationCause::misc(ret_ty.span, fn_hir_id);
                 let param_env = ty::ParamEnv::empty();
 
@@ -2254,7 +2256,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             | ObligationCauseCode::QuestionMark
             | ObligationCauseCode::CheckAssociatedTypeBounds { .. }
             | ObligationCauseCode::LetElse
-            | ObligationCauseCode::BinOp { .. } => {}
+            | ObligationCauseCode::BinOp { .. }
+            | ObligationCauseCode::AscribeUserTypeProvePredicate(..) => {}
             ObligationCauseCode::SliceOrArrayElem => {
                 err.note("slice and array elements must have `Sized` type");
             }
@@ -2709,14 +2712,15 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     let parent_id = hir.get_parent_item(arg_hir_id);
                     let typeck_results: &TypeckResults<'tcx> = match &in_progress_typeck_results {
                         Some(t) if t.hir_owner == parent_id => t,
-                        _ => self.tcx.typeck(parent_id),
+                        _ => self.tcx.typeck(parent_id.def_id),
                     };
-                    let ty = typeck_results.expr_ty_adjusted(expr);
-                    let span = expr.peel_blocks().span;
+                    let expr = expr.peel_blocks();
+                    let ty = typeck_results.expr_ty_adjusted_opt(expr).unwrap_or(tcx.ty_error());
+                    let span = expr.span;
                     if Some(span) != err.span.primary_span() {
                         err.span_label(
                             span,
-                            &if ty.references_error() {
+                            if ty.references_error() {
                                 String::new()
                             } else {
                                 format!("this tail expression is of type `{:?}`", ty)
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index d840677f1ca8..6f3a9412dde7 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -25,10 +25,9 @@ use super::Unimplemented;
 use super::{FulfillmentError, FulfillmentErrorCode};
 use super::{ObligationCause, PredicateObligation};
 
-use crate::traits::error_reporting::InferCtxtExt as _;
 use crate::traits::project::PolyProjectionObligation;
 use crate::traits::project::ProjectionCacheKeyExt as _;
-use crate::traits::query::evaluate_obligation::InferCtxtExt as _;
+use crate::traits::query::evaluate_obligation::InferCtxtExt;
 
 impl<'tcx> ForestObligation for PendingPredicateObligation<'tcx> {
     /// Note that we include both the `ParamEnv` and the `Predicate`,
@@ -135,7 +134,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
     /// `SomeTrait` or a where-clause that lets us unify `$0` with
     /// something concrete. If this fails, we'll unify `$0` with
     /// `projection_ty` again.
-    #[tracing::instrument(level = "debug", skip(self, infcx, param_env, cause))]
+    #[instrument(level = "debug", skip(self, infcx, param_env, cause))]
     fn normalize_projection_type(
         &mut self,
         infcx: &InferCtxt<'_, 'tcx>,
@@ -224,6 +223,7 @@ fn mk_pending(os: Vec<PredicateObligation<'_>>) -> Vec<PendingPredicateObligatio
 impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
     type Obligation = PendingPredicateObligation<'tcx>;
     type Error = FulfillmentErrorCode<'tcx>;
+    type OUT = Outcome<Self::Obligation, Self::Error>;
 
     /// Identifies whether a predicate obligation needs processing.
     ///
@@ -427,16 +427,14 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
                         obligation.param_env,
                         Binder::dummy(subtype),
                     ) {
-                        None => {
+                        Err((a, b)) => {
                             // None means that both are unresolved.
-                            pending_obligation.stalled_on = vec![
-                                TyOrConstInferVar::maybe_from_ty(subtype.a).unwrap(),
-                                TyOrConstInferVar::maybe_from_ty(subtype.b).unwrap(),
-                            ];
+                            pending_obligation.stalled_on =
+                                vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)];
                             ProcessResult::Unchanged
                         }
-                        Some(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
-                        Some(Err(err)) => {
+                        Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
+                        Ok(Err(err)) => {
                             let expected_found =
                                 ExpectedFound::new(subtype.a_is_expected, subtype.a, subtype.b);
                             ProcessResult::Error(FulfillmentErrorCode::CodeSubtypeError(
@@ -453,16 +451,14 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
                         obligation.param_env,
                         Binder::dummy(coerce),
                     ) {
-                        None => {
+                        Err((a, b)) => {
                             // None means that both are unresolved.
-                            pending_obligation.stalled_on = vec![
-                                TyOrConstInferVar::maybe_from_ty(coerce.a).unwrap(),
-                                TyOrConstInferVar::maybe_from_ty(coerce.b).unwrap(),
-                            ];
+                            pending_obligation.stalled_on =
+                                vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)];
                             ProcessResult::Unchanged
                         }
-                        Some(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
-                        Some(Err(err)) => {
+                        Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
+                        Ok(Err(err)) => {
                             let expected_found = ExpectedFound::new(false, coerce.a, coerce.b);
                             ProcessResult::Error(FulfillmentErrorCode::CodeSubtypeError(
                                 expected_found,
@@ -509,11 +505,7 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
                         if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) =
                             (c1.kind(), c2.kind())
                         {
-                            if infcx.try_unify_abstract_consts(
-                                a.shrink(),
-                                b.shrink(),
-                                obligation.param_env,
-                            ) {
+                            if infcx.try_unify_abstract_consts(a, b, obligation.param_env) {
                                 return ProcessResult::Changed(vec![]);
                             }
                         }
@@ -602,14 +594,16 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
         &mut self,
         cycle: I,
         _marker: PhantomData<&'c PendingPredicateObligation<'tcx>>,
-    ) where
+    ) -> Result<(), FulfillmentErrorCode<'tcx>>
+    where
         I: Clone + Iterator<Item = &'c PendingPredicateObligation<'tcx>>,
     {
         if self.selcx.coinductive_match(cycle.clone().map(|s| s.obligation.predicate)) {
             debug!("process_child_obligations: coinductive match");
+            Ok(())
         } else {
             let cycle: Vec<_> = cycle.map(|c| c.obligation.clone()).collect();
-            self.selcx.infcx().report_overflow_error_cycle(&cycle);
+            Err(FulfillmentErrorCode::CodeCycle(cycle))
         }
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index e11ea7751aa7..8da68c225d8e 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -23,6 +23,7 @@ mod structural_match;
 mod util;
 pub mod wf;
 
+use crate::errors::DumpVTableEntries;
 use crate::infer::outlives::env::OutlivesEnvironment;
 use crate::infer::{InferCtxt, TyCtxtInferExt};
 use crate::traits::error_reporting::InferCtxtExt as _;
@@ -33,12 +34,11 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_infer::traits::TraitEngineExt as _;
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{
-    self, DefIdTree, GenericParamDefKind, Subst, ToPredicate, Ty, TyCtxt, TypeSuperVisitable,
-    VtblEntry,
+    self, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TyCtxt, TypeSuperVisitable, VtblEntry,
 };
+use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_span::{sym, Span};
 use smallvec::SmallVec;
 
@@ -129,7 +129,7 @@ pub fn predicates_for_generics<'tcx>(
         move |(idx, (predicate, span))| Obligation {
             cause: cause(idx, span),
             recursion_depth: 0,
-            param_env: param_env,
+            param_env,
             predicate,
         },
     )
@@ -763,8 +763,11 @@ fn dump_vtable_entries<'tcx>(
     trait_ref: ty::PolyTraitRef<'tcx>,
     entries: &[VtblEntry<'tcx>],
 ) {
-    let msg = format!("vtable entries for `{}`: {:#?}", trait_ref, entries);
-    tcx.sess.struct_span_err(sp, &msg).emit();
+    tcx.sess.emit_err(DumpVTableEntries {
+        span: sp,
+        trait_ref,
+        entries: format!("{:#?}", entries),
+    });
 }
 
 fn own_existential_vtable_entries<'tcx>(
@@ -967,7 +970,7 @@ pub fn provide(providers: &mut ty::query::Providers) {
     *providers = ty::query::Providers {
         specialization_graph_of: specialize::specialization_graph_provider,
         specializes: specialize::specializes,
-        codegen_fulfill_obligation: codegen::codegen_fulfill_obligation,
+        codegen_select_candidate: codegen::codegen_select_candidate,
         own_existential_vtable_entries,
         vtable_entries,
         vtable_trait_upcasting_coercion_new_vptr_slot,
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 612f51309088..2773b61e9ba6 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -13,14 +13,15 @@ use super::elaborate_predicates;
 use crate::infer::TyCtxtInferExt;
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::{self, Obligation, ObligationCause};
+use hir::def::DefKind;
 use rustc_errors::{FatalError, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::abstract_const::{walk_abstract_const, AbstractConst};
-use rustc_middle::ty::subst::{GenericArg, InternalSubsts, Subst};
 use rustc_middle::ty::{
     self, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
+use rustc_middle::ty::{GenericArg, InternalSubsts};
 use rustc_middle::ty::{Predicate, ToPredicate};
 use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY;
 use rustc_span::symbol::Symbol;
@@ -431,6 +432,9 @@ fn virtual_call_violation_for_method<'tcx>(
     if contains_illegal_self_type_reference(tcx, trait_def_id, sig.output()) {
         return Some(MethodViolationCode::ReferencesSelfOutput);
     }
+    if contains_illegal_impl_trait_in_trait(tcx, sig.output()) {
+        return Some(MethodViolationCode::ReferencesImplTraitInTrait);
+    }
 
     // We can't monomorphize things like `fn foo<A>(...)`.
     let own_counts = tcx.generics_of(method.def_id).own_counts();
@@ -596,7 +600,7 @@ fn object_ty_for_trait<'tcx>(
     let existential_predicates = tcx
         .mk_poly_existential_predicates(iter::once(trait_predicate).chain(projection_predicates));
 
-    let object_ty = tcx.mk_dynamic(existential_predicates, lifetime);
+    let object_ty = tcx.mk_dynamic(existential_predicates, lifetime, ty::Dyn);
 
     debug!("object_ty_for_trait: object_ty=`{}`", object_ty);
 
@@ -793,6 +797,12 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
                         ControlFlow::CONTINUE
                     }
                 }
+                ty::Projection(ref data)
+                    if self.tcx.def_kind(data.item_def_id) == DefKind::ImplTraitPlaceholder =>
+                {
+                    // We'll deny these later in their own pass
+                    ControlFlow::CONTINUE
+                }
                 ty::Projection(ref data) => {
                     // This is a projected type `<Foo as SomeTrait>::X`.
 
@@ -828,7 +838,10 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
             }
         }
 
-        fn visit_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_ty_unevaluated(
+            &mut self,
+            uv: ty::UnevaluatedConst<'tcx>,
+        ) -> ControlFlow<Self::BreakTy> {
             // Constants can only influence object safety if they reference `Self`.
             // This is only possible for unevaluated constants, so we walk these here.
             //
@@ -842,7 +855,7 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
             // This shouldn't really matter though as we can't really use any
             // constants which are not considered const evaluatable.
             use rustc_middle::ty::abstract_const::Node;
-            if let Ok(Some(ct)) = AbstractConst::new(self.tcx, uv.shrink()) {
+            if let Ok(Some(ct)) = AbstractConst::new(self.tcx, uv) {
                 walk_abstract_const(self.tcx, ct, |node| match node.root(self.tcx) {
                     Node::Leaf(leaf) => self.visit_const(leaf),
                     Node::Cast(_, _, ty) => self.visit_ty(ty),
@@ -861,6 +874,22 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
         .is_break()
 }
 
+pub fn contains_illegal_impl_trait_in_trait<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    ty: ty::Binder<'tcx, Ty<'tcx>>,
+) -> bool {
+    // FIXME(RPITIT): Perhaps we should use a visitor here?
+    ty.skip_binder().walk().any(|arg| {
+        if let ty::GenericArgKind::Type(ty) = arg.unpack()
+            && let ty::Projection(proj) = ty.kind()
+        {
+            tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
+        } else {
+            false
+        }
+    })
+}
+
 pub fn provide(providers: &mut ty::query::Providers) {
     *providers = ty::query::Providers { object_safety_violations, ..*providers };
 }
diff --git a/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
index 9227bbf011db..4a4f34b76805 100644
--- a/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
@@ -8,6 +8,10 @@ use rustc_parse_format::{ParseMode, Parser, Piece, Position};
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 
+use crate::errors::{
+    EmptyOnClauseInOnUnimplemented, InvalidOnClauseInOnUnimplemented, NoValueInOnUnimplemented,
+};
+
 #[derive(Clone, Debug)]
 pub struct OnUnimplementedFormatString(Symbol);
 
@@ -18,7 +22,7 @@ pub struct OnUnimplementedDirective {
     pub message: Option<OnUnimplementedFormatString>,
     pub label: Option<OnUnimplementedFormatString>,
     pub note: Option<OnUnimplementedFormatString>,
-    pub enclosing_scope: Option<OnUnimplementedFormatString>,
+    pub parent_label: Option<OnUnimplementedFormatString>,
     pub append_const_msg: Option<Option<Symbol>>,
 }
 
@@ -27,7 +31,7 @@ pub struct OnUnimplementedNote {
     pub message: Option<String>,
     pub label: Option<String>,
     pub note: Option<String>,
-    pub enclosing_scope: Option<String>,
+    pub parent_label: Option<String>,
     /// Append a message for `~const Trait` errors. `None` means not requested and
     /// should fallback to a generic message, `Some(None)` suggests using the default
     /// appended message, `Some(Some(s))` suggests use the `s` message instead of the
@@ -35,21 +39,6 @@ pub struct OnUnimplementedNote {
     pub append_const_msg: Option<Option<Symbol>>,
 }
 
-fn parse_error(
-    tcx: TyCtxt<'_>,
-    span: Span,
-    message: &str,
-    label: &str,
-    note: Option<&str>,
-) -> ErrorGuaranteed {
-    let mut diag = struct_span_err!(tcx.sess, span, E0232, "{}", message);
-    diag.span_label(span, label);
-    if let Some(note) = note {
-        diag.note(note);
-    }
-    diag.emit()
-}
-
 impl<'tcx> OnUnimplementedDirective {
     fn parse(
         tcx: TyCtxt<'tcx>,
@@ -70,25 +59,9 @@ impl<'tcx> OnUnimplementedDirective {
         } else {
             let cond = item_iter
                 .next()
-                .ok_or_else(|| {
-                    parse_error(
-                        tcx,
-                        span,
-                        "empty `on`-clause in `#[rustc_on_unimplemented]`",
-                        "empty on-clause here",
-                        None,
-                    )
-                })?
+                .ok_or_else(|| tcx.sess.emit_err(EmptyOnClauseInOnUnimplemented { span }))?
                 .meta_item()
-                .ok_or_else(|| {
-                    parse_error(
-                        tcx,
-                        span,
-                        "invalid `on`-clause in `#[rustc_on_unimplemented]`",
-                        "invalid on-clause here",
-                        None,
-                    )
-                })?;
+                .ok_or_else(|| tcx.sess.emit_err(InvalidOnClauseInOnUnimplemented { span }))?;
             attr::eval_condition(cond, &tcx.sess.parse_sess, Some(tcx.features()), &mut |cfg| {
                 if let Some(value) = cfg.value && let Err(guar) = parse_value(value) {
                     errored = Some(guar);
@@ -101,7 +74,7 @@ impl<'tcx> OnUnimplementedDirective {
         let mut message = None;
         let mut label = None;
         let mut note = None;
-        let mut enclosing_scope = None;
+        let mut parent_label = None;
         let mut subcommands = vec![];
         let mut append_const_msg = None;
 
@@ -121,9 +94,9 @@ impl<'tcx> OnUnimplementedDirective {
                     note = parse_value(note_)?;
                     continue;
                 }
-            } else if item.has_name(sym::enclosing_scope) && enclosing_scope.is_none() {
-                if let Some(enclosing_scope_) = item.value_str() {
-                    enclosing_scope = parse_value(enclosing_scope_)?;
+            } else if item.has_name(sym::parent_label) && parent_label.is_none() {
+                if let Some(parent_label_) = item.value_str() {
+                    parent_label = parse_value(parent_label_)?;
                     continue;
                 }
             } else if item.has_name(sym::on)
@@ -150,13 +123,7 @@ impl<'tcx> OnUnimplementedDirective {
             }
 
             // nothing found
-            parse_error(
-                tcx,
-                item.span(),
-                "this attribute must have a valid value",
-                "expected value here",
-                Some(r#"eg `#[rustc_on_unimplemented(message="foo")]`"#),
-            );
+            tcx.sess.emit_err(NoValueInOnUnimplemented { span: item.span() });
         }
 
         if let Some(reported) = errored {
@@ -168,7 +135,7 @@ impl<'tcx> OnUnimplementedDirective {
                 message,
                 label,
                 note,
-                enclosing_scope,
+                parent_label,
                 append_const_msg,
             })
         }
@@ -193,7 +160,7 @@ impl<'tcx> OnUnimplementedDirective {
                     attr.span,
                 )?),
                 note: None,
-                enclosing_scope: None,
+                parent_label: None,
                 append_const_msg: None,
             }))
         } else {
@@ -214,7 +181,7 @@ impl<'tcx> OnUnimplementedDirective {
         let mut message = None;
         let mut label = None;
         let mut note = None;
-        let mut enclosing_scope = None;
+        let mut parent_label = None;
         let mut append_const_msg = None;
         info!("evaluate({:?}, trait_ref={:?}, options={:?})", self, trait_ref, options);
 
@@ -250,8 +217,8 @@ impl<'tcx> OnUnimplementedDirective {
                 note = Some(note_.clone());
             }
 
-            if let Some(ref enclosing_scope_) = command.enclosing_scope {
-                enclosing_scope = Some(enclosing_scope_.clone());
+            if let Some(ref parent_label_) = command.parent_label {
+                parent_label = Some(parent_label_.clone());
             }
 
             append_const_msg = command.append_const_msg;
@@ -261,7 +228,7 @@ impl<'tcx> OnUnimplementedDirective {
             label: label.map(|l| l.format(tcx, trait_ref, &options_map)),
             message: message.map(|m| m.format(tcx, trait_ref, &options_map)),
             note: note.map(|n| n.format(tcx, trait_ref, &options_map)),
-            enclosing_scope: enclosing_scope.map(|e_s| e_s.format(tcx, trait_ref, &options_map)),
+            parent_label: parent_label.map(|e_s| e_s.format(tcx, trait_ref, &options_map)),
             append_const_msg,
         }
     }
diff --git a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
index a4b540182280..3008dfcadde9 100644
--- a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
+++ b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
@@ -46,7 +46,7 @@ impl<'a, 'cx, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'cx, 'tcx> {
     ///   Note that this may cause outlives obligations to be injected
     ///   into the inference context with this body-id.
     /// - `ty`, the type that we are supposed to assume is WF.
-    #[instrument(level = "debug", skip(self, param_env, body_id))]
+    #[instrument(level = "debug", skip(self, param_env, body_id), ret)]
     fn implied_outlives_bounds(
         &self,
         param_env: ty::ParamEnv<'tcx>,
@@ -71,6 +71,7 @@ impl<'a, 'cx, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'cx, 'tcx> {
         let TypeOpOutput { output, constraints, .. } = result;
 
         if let Some(constraints) = constraints {
+            debug!(?constraints);
             // Instantiation may have produced new inference variables and constraints on those
             // variables. Process these constraints.
             let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(self.tcx);
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 444ca6471e2e..07b65a9748d7 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -30,8 +30,8 @@ use rustc_hir::lang_items::LangItem;
 use rustc_infer::infer::resolve::OpportunisticRegionResolver;
 use rustc_middle::traits::select::OverflowError;
 use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable};
+use rustc_middle::ty::DefIdTree;
 use rustc_middle::ty::{self, Term, ToPredicate, Ty, TyCtxt};
 use rustc_span::symbol::sym;
 
@@ -70,6 +70,8 @@ enum ProjectionCandidate<'tcx> {
 
     /// From an "impl" (or a "pseudo-impl" returned by select)
     Select(Selection<'tcx>),
+
+    ImplTraitInTrait(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>),
 }
 
 enum ProjectionCandidateSet<'tcx> {
@@ -231,7 +233,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>(
 /// If successful, this may result in additional obligations.
 ///
 /// See [poly_project_and_unify_type] for an explanation of the return value.
-#[tracing::instrument(level = "debug", skip(selcx))]
+#[instrument(level = "debug", skip(selcx))]
 fn project_and_unify_type<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionObligation<'tcx>,
@@ -497,7 +499,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
             // This is really important. While we *can* handle this, this has
             // severe performance implications for large opaque types with
             // late-bound regions. See `issue-88862` benchmark.
-            ty::Opaque(def_id, substs) if !substs.has_escaping_bound_vars() => {
+            ty::Opaque(def_id, substs) => {
                 // Only normalize `impl Trait` outside of type inference, usually in codegen.
                 match self.param_env.reveal() {
                     Reveal::UserFacing => ty.super_fold_with(self),
@@ -552,7 +554,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
                     )
                     .ok()
                     .flatten()
-                    .unwrap_or_else(|| ty::Term::Ty(ty.super_fold_with(self)))
+                    .unwrap_or_else(|| ty.super_fold_with(self).into())
                 };
                 // For cases like #95134 we would like to catch overflows early
                 // otherwise they slip away away and cause ICE.
@@ -635,13 +637,18 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
 
     #[instrument(skip(self), level = "debug")]
     fn fold_const(&mut self, constant: ty::Const<'tcx>) -> ty::Const<'tcx> {
-        if self.selcx.tcx().lazy_normalization() || !self.eager_inference_replacement {
+        let tcx = self.selcx.tcx();
+        if tcx.lazy_normalization() {
             constant
         } else {
             let constant = constant.super_fold_with(self);
-            debug!(?constant);
-            debug!("self.param_env: {:?}", self.param_env);
-            constant.eval(self.selcx.tcx(), self.param_env)
+            debug!(?constant, ?self.param_env);
+            with_replaced_escaping_bound_vars(
+                self.selcx.infcx(),
+                &mut self.universes,
+                constant,
+                |constant| constant.eval(tcx, self.param_env),
+            )
         }
     }
 
@@ -671,6 +678,41 @@ pub struct BoundVarReplacer<'me, 'tcx> {
     universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>,
 }
 
+/// Executes `f` on `value` after replacing all escaping bound variables with placeholders
+/// and then replaces these placeholders with the original bound variables in the result.
+///
+/// In most places, bound variables should be replaced right when entering a binder, making
+/// this function unnecessary. However, normalization currently does not do that, so we have
+/// to do this lazily.
+///
+/// You should not add any additional uses of this function, at least not without first
+/// discussing it with t-types.
+///
+/// FIXME(@lcnr): We may even consider experimenting with eagerly replacing bound vars during
+/// normalization as well, at which point this function will be unnecessary and can be removed.
+pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: TypeFoldable<'tcx>>(
+    infcx: &'a InferCtxt<'a, 'tcx>,
+    universe_indices: &'a mut Vec<Option<ty::UniverseIndex>>,
+    value: T,
+    f: impl FnOnce(T) -> R,
+) -> R {
+    if value.has_escaping_bound_vars() {
+        let (value, mapped_regions, mapped_types, mapped_consts) =
+            BoundVarReplacer::replace_bound_vars(infcx, universe_indices, value);
+        let result = f(value);
+        PlaceholderReplacer::replace_placeholders(
+            infcx,
+            mapped_regions,
+            mapped_types,
+            mapped_consts,
+            universe_indices,
+            result,
+        )
+    } else {
+        f(value)
+    }
+}
+
 impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
     /// Returns `Some` if we *were* able to replace bound vars. If there are any bound vars that
     /// use a binding level above `universe_indices.len()`, we fail.
@@ -1206,7 +1248,7 @@ impl<'tcx> Progress<'tcx> {
 ///
 /// IMPORTANT:
 /// - `obligation` must be fully normalized
-#[tracing::instrument(level = "info", skip(selcx))]
+#[instrument(level = "info", skip(selcx))]
 fn project<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
@@ -1225,6 +1267,8 @@ fn project<'cx, 'tcx>(
 
     let mut candidates = ProjectionCandidateSet::None;
 
+    assemble_candidate_for_impl_trait_in_trait(selcx, obligation, &mut candidates);
+
     // Make sure that the following procedures are kept in order. ParamEnv
     // needs to be first because it has highest priority, and Select checks
     // the return value of push_candidate which assumes it's ran at last.
@@ -1263,6 +1307,48 @@ fn project<'cx, 'tcx>(
     }
 }
 
+/// If the predicate's item is an `ImplTraitPlaceholder`, we do a select on the
+/// corresponding trait ref. If this yields an `impl`, then we're able to project
+/// to a concrete type, since we have an `impl`'s method  to provide the RPITIT.
+fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
+    obligation: &ProjectionTyObligation<'tcx>,
+    candidate_set: &mut ProjectionCandidateSet<'tcx>,
+) {
+    let tcx = selcx.tcx();
+    if tcx.def_kind(obligation.predicate.item_def_id) == DefKind::ImplTraitPlaceholder {
+        let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.item_def_id);
+        let trait_def_id = tcx.parent(trait_fn_def_id);
+        let trait_substs =
+            obligation.predicate.substs.truncate_to(tcx, tcx.generics_of(trait_def_id));
+        // FIXME(named-returns): Binders
+        let trait_predicate =
+            ty::Binder::dummy(ty::TraitRef { def_id: trait_def_id, substs: trait_substs })
+                .to_poly_trait_predicate();
+
+        let _ =
+            selcx.infcx().commit_if_ok(|_| match selcx.select(&obligation.with(trait_predicate)) {
+                Ok(Some(super::ImplSource::UserDefined(data))) => {
+                    candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data));
+                    Ok(())
+                }
+                Ok(None) => {
+                    candidate_set.mark_ambiguous();
+                    return Err(());
+                }
+                Ok(Some(_)) => {
+                    // Don't know enough about the impl to provide a useful signature
+                    return Err(());
+                }
+                Err(e) => {
+                    debug!(error = ?e, "selection error");
+                    candidate_set.mark_error(e);
+                    return Err(());
+                }
+            });
+    }
+}
+
 /// The first thing we have to do is scan through the parameter
 /// environment to see whether there are any projection predicates
 /// there that can answer this question.
@@ -1368,7 +1454,7 @@ fn assemble_candidates_from_object_ty<'cx, 'tcx>(
     );
 }
 
-#[tracing::instrument(
+#[instrument(
     level = "debug",
     skip(selcx, candidate_set, ctor, env_predicates, potentially_unnormalized_candidates)
 )]
@@ -1419,12 +1505,17 @@ fn assemble_candidates_from_predicates<'cx, 'tcx>(
     }
 }
 
-#[tracing::instrument(level = "debug", skip(selcx, obligation, candidate_set))]
+#[instrument(level = "debug", skip(selcx, obligation, candidate_set))]
 fn assemble_candidates_from_impls<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
     candidate_set: &mut ProjectionCandidateSet<'tcx>,
 ) {
+    // Can't assemble candidate from impl for RPITIT
+    if selcx.tcx().def_kind(obligation.predicate.item_def_id) == DefKind::ImplTraitPlaceholder {
+        return;
+    }
+
     // If we are resolving `<T as TraitRef<...>>::Item == Type`,
     // start out by selecting the predicate `T as TraitRef<...>`:
     let poly_trait_ref = ty::Binder::dummy(obligation.predicate.trait_ref(selcx.tcx()));
@@ -1659,7 +1750,8 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
             super::ImplSource::AutoImpl(..)
             | super::ImplSource::Builtin(..)
             | super::ImplSource::TraitUpcasting(_)
-            | super::ImplSource::ConstDestruct(_) => {
+            | super::ImplSource::ConstDestruct(_)
+            | super::ImplSource::Tuple => {
                 // These traits have no associated types.
                 selcx.tcx().sess.delay_span_bug(
                     obligation.cause.span,
@@ -1700,6 +1792,9 @@ fn confirm_candidate<'cx, 'tcx>(
         ProjectionCandidate::Select(impl_source) => {
             confirm_select_candidate(selcx, obligation, impl_source)
         }
+        ProjectionCandidate::ImplTraitInTrait(data) => {
+            confirm_impl_trait_in_trait_candidate(selcx, obligation, data)
+        }
     };
 
     // When checking for cycle during evaluation, we compare predicates with
@@ -1734,7 +1829,8 @@ fn confirm_select_candidate<'cx, 'tcx>(
         | super::ImplSource::Builtin(..)
         | super::ImplSource::TraitUpcasting(_)
         | super::ImplSource::TraitAlias(..)
-        | super::ImplSource::ConstDestruct(_) => {
+        | super::ImplSource::ConstDestruct(_)
+        | super::ImplSource::Tuple => {
             // we don't create Select candidates with this kind of resolution
             span_bug!(
                 obligation.cause.span,
@@ -2045,7 +2141,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
         let identity_substs =
             crate::traits::InternalSubsts::identity_for_item(tcx, assoc_ty.item.def_id);
         let did = ty::WithOptConstParam::unknown(assoc_ty.item.def_id);
-        let kind = ty::ConstKind::Unevaluated(ty::Unevaluated::new(did, identity_substs));
+        let kind = ty::ConstKind::Unevaluated(ty::UnevaluatedConst::new(did, identity_substs));
         ty.map_bound(|ty| tcx.mk_const(ty::ConstS { ty, kind }).into())
     } else {
         ty.map_bound(|ty| ty.into())
@@ -2062,10 +2158,74 @@ fn confirm_impl_candidate<'cx, 'tcx>(
     }
 }
 
+fn confirm_impl_trait_in_trait_candidate<'tcx>(
+    selcx: &mut SelectionContext<'_, 'tcx>,
+    obligation: &ProjectionTyObligation<'tcx>,
+    data: ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>,
+) -> Progress<'tcx> {
+    let tcx = selcx.tcx();
+    let mut obligations = data.nested;
+
+    let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.item_def_id);
+    let Ok(leaf_def) = assoc_def(selcx, data.impl_def_id, trait_fn_def_id) else {
+        return Progress { term: tcx.ty_error().into(), obligations };
+    };
+    if !leaf_def.item.defaultness(tcx).has_value() {
+        return Progress { term: tcx.ty_error().into(), obligations };
+    }
+
+    let impl_fn_def_id = leaf_def.item.def_id;
+    let impl_fn_substs = obligation.predicate.substs.rebase_onto(tcx, trait_fn_def_id, data.substs);
+
+    let cause = ObligationCause::new(
+        obligation.cause.span,
+        obligation.cause.body_id,
+        super::ItemObligation(impl_fn_def_id),
+    );
+    let predicates = normalize_with_depth_to(
+        selcx,
+        obligation.param_env,
+        cause.clone(),
+        obligation.recursion_depth + 1,
+        tcx.predicates_of(impl_fn_def_id).instantiate(tcx, impl_fn_substs),
+        &mut obligations,
+    );
+    obligations.extend(std::iter::zip(predicates.predicates, predicates.spans).map(
+        |(pred, span)| {
+            Obligation::with_depth(
+                ObligationCause::new(
+                    obligation.cause.span,
+                    obligation.cause.body_id,
+                    if span.is_dummy() {
+                        super::ItemObligation(impl_fn_def_id)
+                    } else {
+                        super::BindingObligation(impl_fn_def_id, span)
+                    },
+                ),
+                obligation.recursion_depth + 1,
+                obligation.param_env,
+                pred,
+            )
+        },
+    ));
+
+    let ty = super::normalize_to(
+        selcx,
+        obligation.param_env,
+        cause.clone(),
+        tcx.bound_trait_impl_trait_tys(impl_fn_def_id)
+            .map_bound(|tys| {
+                tys.map_or_else(|_| tcx.ty_error(), |tys| tys[&obligation.predicate.item_def_id])
+            })
+            .subst(tcx, impl_fn_substs),
+        &mut obligations,
+    );
+
+    Progress { term: ty.into(), obligations }
+}
+
 // Get obligations corresponding to the predicates from the where-clause of the
 // associated type itself.
-// Note: `feature(generic_associated_types)` is required to write such
-// predicates, even for non-generic associated types.
 fn assoc_ty_own_obligations<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
index 61c556b726d6..31e7fb67f0ef 100644
--- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
@@ -6,14 +6,13 @@ use crate::infer::at::At;
 use crate::infer::canonical::OriginalQueryValues;
 use crate::infer::{InferCtxt, InferOk};
 use crate::traits::error_reporting::InferCtxtExt;
-use crate::traits::project::needs_normalization;
+use crate::traits::project::{needs_normalization, BoundVarReplacer, PlaceholderReplacer};
 use crate::traits::{Obligation, ObligationCause, PredicateObligation, Reveal};
 use rustc_data_structures::sso::SsoHashMap;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_infer::traits::Normalized;
 use rustc_middle::mir;
 use rustc_middle::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitor};
 
@@ -48,10 +47,11 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
         T: TypeFoldable<'tcx>,
     {
         debug!(
-            "normalize::<{}>(value={:?}, param_env={:?})",
+            "normalize::<{}>(value={:?}, param_env={:?}, cause={:?})",
             std::any::type_name::<T>(),
             value,
             self.param_env,
+            self.cause,
         );
         if !needs_normalization(&value, self.param_env.reveal()) {
             return Ok(Normalized { value, obligations: vec![] });
@@ -198,7 +198,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
             // This is really important. While we *can* handle this, this has
             // severe performance implications for large opaque types with
             // late-bound regions. See `issue-88862` benchmark.
-            ty::Opaque(def_id, substs) if !substs.has_escaping_bound_vars() => {
+            ty::Opaque(def_id, substs) => {
                 // Only normalize `impl Trait` outside of type inference, usually in codegen.
                 match self.param_env.reveal() {
                     Reveal::UserFacing => ty.try_super_fold_with(self),
@@ -283,11 +283,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                 let tcx = self.infcx.tcx;
                 let infcx = self.infcx;
                 let (data, mapped_regions, mapped_types, mapped_consts) =
-                    crate::traits::project::BoundVarReplacer::replace_bound_vars(
-                        infcx,
-                        &mut self.universes,
-                        data,
-                    );
+                    BoundVarReplacer::replace_bound_vars(infcx, &mut self.universes, data);
                 let data = data.try_fold_with(self)?;
 
                 let mut orig_values = OriginalQueryValues::default();
@@ -313,8 +309,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                 debug!("QueryNormalizer: result = {:#?}", result);
                 debug!("QueryNormalizer: obligations = {:#?}", obligations);
                 self.obligations.extend(obligations);
-
-                let res = crate::traits::project::PlaceholderReplacer::replace_placeholders(
+                let res = PlaceholderReplacer::replace_placeholders(
                     infcx,
                     mapped_regions,
                     mapped_types,
@@ -343,30 +338,20 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
         constant: ty::Const<'tcx>,
     ) -> Result<ty::Const<'tcx>, Self::Error> {
         let constant = constant.try_super_fold_with(self)?;
-        Ok(constant.eval(self.infcx.tcx, self.param_env))
+        debug!(?constant, ?self.param_env);
+        Ok(crate::traits::project::with_replaced_escaping_bound_vars(
+            self.infcx,
+            &mut self.universes,
+            constant,
+            |constant| constant.eval(self.infcx.tcx, self.param_env),
+        ))
     }
 
     fn try_fold_mir_const(
         &mut self,
         constant: mir::ConstantKind<'tcx>,
     ) -> Result<mir::ConstantKind<'tcx>, Self::Error> {
-        Ok(match constant {
-            mir::ConstantKind::Ty(c) => {
-                let const_folded = c.try_super_fold_with(self)?;
-                match const_folded.kind() {
-                    ty::ConstKind::Value(valtree) => {
-                        let tcx = self.infcx.tcx;
-                        let ty = const_folded.ty();
-                        let const_val = tcx.valtree_to_const_val((ty, valtree));
-                        debug!(?ty, ?valtree, ?const_val);
-
-                        mir::ConstantKind::Val(const_val, ty)
-                    }
-                    _ => mir::ConstantKind::Ty(const_folded),
-                }
-            }
-            mir::ConstantKind::Val(_, _) => constant.try_super_fold_with(self)?,
-        })
+        constant.try_super_fold_with(self)
     }
 
     #[inline]
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
index f6e196e31414..18988861add1 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
@@ -23,7 +23,7 @@ impl<F, G> CustomTypeOp<F, G> {
     }
 }
 
-impl<'tcx, F, R, G> super::TypeOp<'tcx> for CustomTypeOp<F, G>
+impl<'tcx, F, R: fmt::Debug, G> super::TypeOp<'tcx> for CustomTypeOp<F, G>
 where
     F: for<'a, 'cx> FnOnce(&'a InferCtxt<'cx, 'tcx>) -> Fallible<InferOk<'tcx, R>>,
     G: Fn() -> String,
@@ -89,8 +89,8 @@ pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>(
         infcx.tcx,
         region_obligations
             .iter()
-            .map(|r_o| (r_o.sup_type, r_o.sub_region))
-            .map(|(ty, r)| (infcx.resolve_vars_if_possible(ty), r)),
+            .map(|r_o| (r_o.sup_type, r_o.sub_region, r_o.origin.to_constraint_category()))
+            .map(|(ty, r, cc)| (infcx.resolve_vars_if_possible(ty), r, cc)),
         &region_constraint_data,
     );
 
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
index 578e1d00cf9e..8a79165702ca 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
@@ -26,7 +26,7 @@ pub use rustc_middle::traits::query::type_op::*;
 /// extract out the resulting region constraints (or an error if it
 /// cannot be completed).
 pub trait TypeOp<'tcx>: Sized + fmt::Debug {
-    type Output;
+    type Output: fmt::Debug;
     type ErrorInfo;
 
     /// Processes the operation and all resulting obligations,
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index d67bd6292b43..451427a69807 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -28,7 +28,7 @@ use super::SelectionCandidate::{self, *};
 use super::{EvaluatedCandidate, SelectionCandidateSet, SelectionContext, TraitObligationStack};
 
 impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     pub(super) fn candidate_from_obligation<'o>(
         &mut self,
         stack: &TraitObligationStack<'o, 'tcx>,
@@ -48,7 +48,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         if let Some(c) =
             self.check_candidate_cache(stack.obligation.param_env, cache_fresh_trait_pred)
         {
-            debug!(candidate = ?c, "CACHE HIT");
+            debug!("CACHE HIT");
             return c;
         }
 
@@ -61,7 +61,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let (candidate, dep_node) =
             self.in_task(|this| this.candidate_from_obligation_no_cache(stack));
 
-        debug!(?candidate, "CACHE MISS");
+        debug!("CACHE MISS");
         self.insert_candidate_cache(
             stack.obligation.param_env,
             cache_fresh_trait_pred,
@@ -309,6 +309,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 // User-defined transmutability impls are permitted.
                 self.assemble_candidates_from_impls(obligation, &mut candidates);
                 self.assemble_candidates_for_transmutability(obligation, &mut candidates);
+            } else if lang_items.tuple_trait() == Some(def_id) {
+                self.assemble_candidate_for_tuple(obligation, &mut candidates);
             } else {
                 if lang_items.clone_trait() == Some(def_id) {
                     // Same builtin conditions as `Copy`, i.e., every type which has builtin support
@@ -337,7 +339,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         Ok(candidates)
     }
 
-    #[tracing::instrument(level = "debug", skip(self, candidates))]
+    #[instrument(level = "debug", skip(self, candidates))]
     fn assemble_candidates_from_projected_tys(
         &mut self,
         obligation: &TraitObligation<'tcx>,
@@ -360,14 +362,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .infcx
             .probe(|_| self.match_projection_obligation_against_definition_bounds(obligation));
 
-        candidates.vec.extend(result.into_iter().map(ProjectionCandidate));
+        candidates
+            .vec
+            .extend(result.into_iter().map(|(idx, constness)| ProjectionCandidate(idx, constness)));
     }
 
     /// Given an obligation like `<SomeTrait for T>`, searches the obligations that the caller
     /// supplied to find out whether it is listed among them.
     ///
     /// Never affects the inference environment.
-    #[tracing::instrument(level = "debug", skip(self, stack, candidates))]
+    #[instrument(level = "debug", skip(self, stack, candidates))]
     fn assemble_candidates_from_caller_bounds<'o>(
         &mut self,
         stack: &TraitObligationStack<'o, 'tcx>,
@@ -880,7 +884,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         };
     }
 
-    #[tracing::instrument(level = "debug", skip(self, obligation, candidates))]
+    #[instrument(level = "debug", skip(self, obligation, candidates))]
     fn assemble_candidates_for_transmutability(
         &mut self,
         obligation: &TraitObligation<'tcx>,
@@ -898,7 +902,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         candidates.vec.push(TransmutabilityCandidate);
     }
 
-    #[tracing::instrument(level = "debug", skip(self, obligation, candidates))]
+    #[instrument(level = "debug", skip(self, obligation, candidates))]
     fn assemble_candidates_for_trait_alias(
         &mut self,
         obligation: &TraitObligation<'tcx>,
@@ -917,7 +921,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
     /// Assembles the trait which are built-in to the language itself:
     /// `Copy`, `Clone` and `Sized`.
-    #[tracing::instrument(level = "debug", skip(self, candidates))]
+    #[instrument(level = "debug", skip(self, candidates))]
     fn assemble_builtin_bound_candidates(
         &mut self,
         conditions: BuiltinImplConditions<'tcx>,
@@ -1009,4 +1013,46 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             }
         }
     }
+
+    fn assemble_candidate_for_tuple(
+        &mut self,
+        obligation: &TraitObligation<'tcx>,
+        candidates: &mut SelectionCandidateSet<'tcx>,
+    ) {
+        let self_ty = self.infcx().shallow_resolve(obligation.self_ty().skip_binder());
+        match self_ty.kind() {
+            ty::Tuple(_) => {
+                candidates.vec.push(TupleCandidate);
+            }
+            ty::Infer(ty::TyVar(_)) => {
+                candidates.ambiguous = true;
+            }
+            ty::Bool
+            | ty::Char
+            | ty::Int(_)
+            | ty::Uint(_)
+            | ty::Float(_)
+            | ty::Adt(_, _)
+            | ty::Foreign(_)
+            | ty::Str
+            | ty::Array(_, _)
+            | ty::Slice(_)
+            | ty::RawPtr(_)
+            | ty::Ref(_, _, _)
+            | ty::FnDef(_, _)
+            | ty::FnPtr(_)
+            | ty::Dynamic(_, _, _)
+            | ty::Closure(_, _)
+            | ty::Generator(_, _, _)
+            | ty::GeneratorWitness(_)
+            | ty::Never
+            | ty::Projection(_)
+            | ty::Opaque(_, _)
+            | ty::Param(_)
+            | ty::Bound(_, _)
+            | ty::Error(_)
+            | ty::Infer(_)
+            | ty::Placeholder(_) => {}
+        }
+    }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 2a1099fc82ab..27fbfb6dd21f 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -11,8 +11,8 @@ use rustc_hir::lang_items::LangItem;
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_infer::infer::InferOk;
 use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType;
-use rustc_middle::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::{self, GenericParamDefKind, Ty, TyCtxt};
+use rustc_middle::ty::{GenericArg, GenericArgKind, InternalSubsts, SubstsRef};
 use rustc_middle::ty::{ToPolyTraitRef, ToPredicate};
 use rustc_span::def_id::DefId;
 
@@ -68,10 +68,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 ImplSource::AutoImpl(data)
             }
 
-            ProjectionCandidate(idx) => {
+            ProjectionCandidate(idx, constness) => {
                 let obligations = self.confirm_projection_candidate(obligation, idx)?;
-                // FIXME(jschievink): constness
-                ImplSource::Param(obligations, ty::BoundConstness::NotConst)
+                ImplSource::Param(obligations, constness)
             }
 
             ObjectCandidate(idx) => {
@@ -126,6 +125,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 let data = self.confirm_const_destruct_candidate(obligation, def_id)?;
                 ImplSource::ConstDestruct(data)
             }
+
+            TupleCandidate => ImplSource::Tuple,
         };
 
         if !obligation.predicate.is_const_if_const() {
@@ -279,29 +280,17 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let predicate = obligation.predicate;
 
         let type_at = |i| predicate.map_bound(|p| p.trait_ref.substs.type_at(i));
-        let bool_at = |i| {
-            predicate
-                .skip_binder()
-                .trait_ref
-                .substs
-                .const_at(i)
-                .try_eval_bool(self.tcx(), obligation.param_env)
-                .unwrap_or(true)
-        };
+        let const_at = |i| predicate.skip_binder().trait_ref.substs.const_at(i);
 
         let src_and_dst = predicate.map_bound(|p| rustc_transmute::Types {
-            src: p.trait_ref.substs.type_at(1),
             dst: p.trait_ref.substs.type_at(0),
+            src: p.trait_ref.substs.type_at(1),
         });
 
         let scope = type_at(2).skip_binder();
 
-        let assume = rustc_transmute::Assume {
-            alignment: bool_at(3),
-            lifetimes: bool_at(4),
-            validity: bool_at(5),
-            visibility: bool_at(6),
-        };
+        let assume =
+            rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, const_at(3));
 
         let cause = obligation.cause.clone();
 
@@ -629,7 +618,36 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         )
         .map_bound(|(trait_ref, _)| trait_ref);
 
-        let nested = self.confirm_poly_trait_refs(obligation, trait_ref)?;
+        let mut nested = self.confirm_poly_trait_refs(obligation, trait_ref)?;
+
+        // Confirm the `type Output: Sized;` bound that is present on `FnOnce`
+        let cause = obligation.derived_cause(BuiltinDerivedObligation);
+        // The binder on the Fn obligation is "less" important than the one on
+        // the signature, as evidenced by how we treat it during projection.
+        // The safe thing to do here is to liberate it, though, which should
+        // have no worse effect than skipping the binder here.
+        let liberated_fn_ty = self.infcx.replace_bound_vars_with_placeholders(obligation.self_ty());
+        let output_ty = self
+            .infcx
+            .replace_bound_vars_with_placeholders(liberated_fn_ty.fn_sig(self.tcx()).output());
+        let output_ty = normalize_with_depth_to(
+            self,
+            obligation.param_env,
+            cause.clone(),
+            obligation.recursion_depth,
+            output_ty,
+            &mut nested,
+        );
+        let tr = ty::Binder::dummy(ty::TraitRef::new(
+            self.tcx().require_lang_item(LangItem::Sized, None),
+            self.tcx().mk_substs_trait(output_ty, &[]),
+        ));
+        nested.push(Obligation::new(
+            cause,
+            obligation.param_env,
+            tr.to_poly_trait_predicate().to_predicate(self.tcx()),
+        ));
+
         Ok(ImplSourceFnPointerData { fn_ty: self_ty, nested })
     }
 
@@ -794,7 +812,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let upcast_trait_ref;
         match (source.kind(), target.kind()) {
             // TraitA+Kx+'a -> TraitB+Ky+'b (trait upcasting coercion).
-            (&ty::Dynamic(ref data_a, r_a), &ty::Dynamic(ref data_b, r_b)) => {
+            (&ty::Dynamic(ref data_a, r_a, repr_a), &ty::Dynamic(ref data_b, r_b, repr_b))
+                if repr_a == repr_b =>
+            {
                 // See `assemble_candidates_for_unsizing` for more info.
                 // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`.
                 let principal_a = data_a.principal().unwrap();
@@ -820,7 +840,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                             .map(ty::Binder::dummy),
                     );
                 let existential_predicates = tcx.mk_poly_existential_predicates(iter);
-                let source_trait = tcx.mk_dynamic(existential_predicates, r_b);
+                let source_trait = tcx.mk_dynamic(existential_predicates, r_b, repr_b);
 
                 // Require that the traits involved in this upcast are **equal**;
                 // only the **lifetime bound** is changed.
@@ -898,7 +918,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let mut nested = vec![];
         match (source.kind(), target.kind()) {
             // Trait+Kx+'a -> Trait+Ky+'b (auto traits and lifetime subtyping).
-            (&ty::Dynamic(ref data_a, r_a), &ty::Dynamic(ref data_b, r_b)) => {
+            (&ty::Dynamic(ref data_a, r_a, ty::Dyn), &ty::Dynamic(ref data_b, r_b, ty::Dyn)) => {
                 // See `assemble_candidates_for_unsizing` for more info.
                 // We already checked the compatibility of auto traits within `assemble_candidates_for_unsizing`.
                 let iter = data_a
@@ -917,7 +937,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                             .map(ty::Binder::dummy),
                     );
                 let existential_predicates = tcx.mk_poly_existential_predicates(iter);
-                let source_trait = tcx.mk_dynamic(existential_predicates, r_b);
+                let source_trait = tcx.mk_dynamic(existential_predicates, r_b, ty::Dyn);
 
                 // Require that the traits involved in this upcast are **equal**;
                 // only the **lifetime bound** is changed.
@@ -944,7 +964,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             }
 
             // `T` -> `Trait`
-            (_, &ty::Dynamic(ref data, r)) => {
+            (_, &ty::Dynamic(ref data, r, ty::Dyn)) => {
                 let mut object_dids = data.auto_traits().chain(data.principal_def_id());
                 if let Some(did) = object_dids.find(|did| !tcx.is_object_safe(*did)) {
                     return Err(TraitNotObjectSafe(did));
@@ -1047,9 +1067,25 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     return Err(Unimplemented);
                 }
 
-                // Extract `TailField<T>` and `TailField<U>` from `Struct<T>` and `Struct<U>`.
-                let source_tail = tail_field_ty.subst(tcx, substs_a);
-                let target_tail = tail_field_ty.subst(tcx, substs_b);
+                // Extract `TailField<T>` and `TailField<U>` from `Struct<T>` and `Struct<U>`,
+                // normalizing in the process, since `type_of` returns something directly from
+                // astconv (which means it's un-normalized).
+                let source_tail = normalize_with_depth_to(
+                    self,
+                    obligation.param_env,
+                    obligation.cause.clone(),
+                    obligation.recursion_depth + 1,
+                    tail_field_ty.subst(tcx, substs_a),
+                    &mut nested,
+                );
+                let target_tail = normalize_with_depth_to(
+                    self,
+                    obligation.param_env,
+                    obligation.cause.clone(),
+                    obligation.recursion_depth + 1,
+                    tail_field_ty.subst(tcx, substs_b),
+                    &mut nested,
+                );
 
                 // Check that the source struct with the target's
                 // unsizing parameters is equal to the target.
@@ -1188,6 +1224,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | ty::Never
                 | ty::Foreign(_) => {}
 
+                // `ManuallyDrop` is trivially drop
+                ty::Adt(def, _) if Some(def.did()) == tcx.lang_items().manually_drop() => {}
+
                 // These types are built-in, so we can fast-track by registering
                 // nested predicates for their constituent type(s)
                 ty::Array(ty, _) | ty::Slice(ty) => {
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 46b50dd92f1e..5e32a27cdb1d 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -37,7 +37,7 @@ use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
 use rustc_middle::ty::fold::BottomUpFolder;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::relate::TypeRelation;
-use rustc_middle::ty::subst::{Subst, SubstsRef};
+use rustc_middle::ty::SubstsRef;
 use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
 use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, TypeVisitable};
 use rustc_span::symbol::sym;
@@ -226,13 +226,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     }
 
     pub fn intercrate(infcx: &'cx InferCtxt<'cx, 'tcx>) -> SelectionContext<'cx, 'tcx> {
-        SelectionContext {
-            infcx,
-            freshener: infcx.freshener_keep_static(),
-            intercrate: true,
-            intercrate_ambiguity_causes: None,
-            query_mode: TraitQueryMode::Standard,
-        }
+        SelectionContext { intercrate: true, ..SelectionContext::new(infcx) }
     }
 
     pub fn with_query_mode(
@@ -240,13 +234,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         query_mode: TraitQueryMode,
     ) -> SelectionContext<'cx, 'tcx> {
         debug!(?query_mode, "with_query_mode");
-        SelectionContext {
-            infcx,
-            freshener: infcx.freshener_keep_static(),
-            intercrate: false,
-            intercrate_ambiguity_causes: None,
-            query_mode,
-        }
+        SelectionContext { query_mode, ..SelectionContext::new(infcx) }
     }
 
     /// Enables tracking of intercrate ambiguity causes. See
@@ -295,7 +283,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
     /// Attempts to satisfy the obligation. If successful, this will affect the surrounding
     /// type environment by performing unification.
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     pub fn select(
         &mut self,
         obligation: &TraitObligation<'tcx>,
@@ -325,10 +313,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 Err(SelectionError::Overflow(OverflowError::Canonical))
             }
             Err(e) => Err(e),
-            Ok(candidate) => {
-                debug!(?candidate, "confirmed");
-                Ok(Some(candidate))
-            }
+            Ok(candidate) => Ok(Some(candidate)),
         }
     }
 
@@ -435,6 +420,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         level = "debug",
         skip(self, previous_stack),
         fields(previous_stack = ?previous_stack.head())
+        ret,
     )]
     fn evaluate_predicate_recursively<'o>(
         &mut self,
@@ -450,7 +436,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             None => self.check_recursion_limit(&obligation, &obligation)?,
         }
 
-        let result = ensure_sufficient_stack(|| {
+        ensure_sufficient_stack(|| {
             let bound_predicate = obligation.predicate.kind();
             match bound_predicate.skip_binder() {
                 ty::PredicateKind::Trait(t) => {
@@ -464,15 +450,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     let p = bound_predicate.rebind(p);
                     // Does this code ever run?
                     match self.infcx.subtype_predicate(&obligation.cause, obligation.param_env, p) {
-                        Some(Ok(InferOk { mut obligations, .. })) => {
+                        Ok(Ok(InferOk { mut obligations, .. })) => {
                             self.add_depth(obligations.iter_mut(), obligation.recursion_depth);
                             self.evaluate_predicates_recursively(
                                 previous_stack,
                                 obligations.into_iter(),
                             )
                         }
-                        Some(Err(_)) => Ok(EvaluatedToErr),
-                        None => Ok(EvaluatedToAmbig),
+                        Ok(Err(_)) => Ok(EvaluatedToErr),
+                        Err(..) => Ok(EvaluatedToAmbig),
                     }
                 }
 
@@ -480,15 +466,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     let p = bound_predicate.rebind(p);
                     // Does this code ever run?
                     match self.infcx.coerce_predicate(&obligation.cause, obligation.param_env, p) {
-                        Some(Ok(InferOk { mut obligations, .. })) => {
+                        Ok(Ok(InferOk { mut obligations, .. })) => {
                             self.add_depth(obligations.iter_mut(), obligation.recursion_depth);
                             self.evaluate_predicates_recursively(
                                 previous_stack,
                                 obligations.into_iter(),
                             )
                         }
-                        Some(Err(_)) => Ok(EvaluatedToErr),
-                        None => Ok(EvaluatedToAmbig),
+                        Ok(Err(_)) => Ok(EvaluatedToErr),
+                        Err(..) => Ok(EvaluatedToAmbig),
                     }
                 }
 
@@ -701,11 +687,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) =
                             (c1.kind(), c2.kind())
                         {
-                            if self.infcx.try_unify_abstract_consts(
-                                a.shrink(),
-                                b.shrink(),
-                                obligation.param_env,
-                            ) {
+                            if self.infcx.try_unify_abstract_consts(a, b, obligation.param_env) {
                                 return Ok(EvaluatedToOk);
                             }
                         }
@@ -760,14 +742,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     bug!("TypeWellFormedFromEnv is only used for chalk")
                 }
             }
-        });
-
-        debug!("finished: {:?} from {:?}", result, obligation);
-
-        result
+        })
     }
 
-    #[instrument(skip(self, previous_stack), level = "debug")]
+    #[instrument(skip(self, previous_stack), level = "debug", ret)]
     fn evaluate_trait_predicate_recursively<'o>(
         &mut self,
         previous_stack: TraitObligationStackList<'o, 'tcx>,
@@ -798,12 +776,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // If a trait predicate is in the (local or global) evaluation cache,
         // then we know it holds without cycles.
         if let Some(result) = self.check_evaluation_cache(param_env, fresh_trait_pred) {
-            debug!(?result, "CACHE HIT");
+            debug!("CACHE HIT");
             return Ok(result);
         }
 
         if let Some(result) = stack.cache().get_provisional(fresh_trait_pred) {
-            debug!(?result, "PROVISIONAL CACHE HIT");
+            debug!("PROVISIONAL CACHE HIT");
             stack.update_reached_depth(result.reached_depth);
             return Ok(result.result);
         }
@@ -826,11 +804,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let reached_depth = stack.reached_depth.get();
         if reached_depth >= stack.depth {
-            debug!(?result, "CACHE MISS");
+            debug!("CACHE MISS");
             self.insert_evaluation_cache(param_env, fresh_trait_pred, dep_node, result);
             stack.cache().on_completion(stack.dfn);
         } else {
-            debug!(?result, "PROVISIONAL");
+            debug!("PROVISIONAL");
             debug!(
                 "caching provisionally because {:?} \
                  is a cycle participant (at depth {}, reached depth {})",
@@ -1023,7 +1001,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     #[instrument(
         level = "debug",
         skip(self, stack),
-        fields(depth = stack.obligation.recursion_depth)
+        fields(depth = stack.obligation.recursion_depth),
+        ret
     )]
     fn evaluate_candidate<'o>(
         &mut self,
@@ -1056,7 +1035,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             result = result.max(EvaluatedToOkModuloRegions);
         }
 
-        debug!(?result);
         Ok(result)
     }
 
@@ -1202,6 +1180,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     ImplCandidate(def_id) if tcx.constness(def_id) == hir::Constness::Const => {}
                     // const param
                     ParamCandidate(trait_pred) if trait_pred.is_const_if_const() => {}
+                    // const projection
+                    ProjectionCandidate(_, ty::BoundConstness::ConstIfConst) => {}
                     // auto trait impl
                     AutoImplCandidate(..) => {}
                     // generator, this will raise error in other places
@@ -1405,11 +1385,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     /// a projection, look at the bounds of `T::Bar`, see if we can find a
     /// `Baz` bound. We return indexes into the list returned by
     /// `tcx.item_bounds` for any applicable bounds.
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     fn match_projection_obligation_against_definition_bounds(
         &mut self,
         obligation: &TraitObligation<'tcx>,
-    ) -> smallvec::SmallVec<[usize; 2]> {
+    ) -> smallvec::SmallVec<[(usize, ty::BoundConstness); 2]> {
         let poly_trait_predicate = self.infcx().resolve_vars_if_possible(obligation.predicate);
         let placeholder_trait_predicate =
             self.infcx().replace_bound_vars_with_placeholders(poly_trait_predicate);
@@ -1435,7 +1415,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // unnecessary ambiguity.
         let mut distinct_normalized_bounds = FxHashSet::default();
 
-        let matching_bounds = bounds
+        bounds
             .iter()
             .enumerate()
             .filter_map(|(idx, bound)| {
@@ -1457,15 +1437,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                             _ => false,
                         }
                     }) {
-                        return Some(idx);
+                        return Some((idx, pred.constness));
                     }
                 }
                 None
             })
-            .collect();
-
-        debug!(?matching_bounds);
-        matching_bounds
+            .collect()
     }
 
     /// Equates the trait in `obligation` with trait bound. If the two traits
@@ -1618,7 +1595,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         };
 
         // (*) Prefer `BuiltinCandidate { has_nested: false }`, `PointeeCandidate`,
-        // `DiscriminantKindCandidate`, and `ConstDestructCandidate` to anything else.
+        // `DiscriminantKindCandidate`, `ConstDestructCandidate`, and `TupleCandidate`
+        // to anything else.
         //
         // This is a fix for #53123 and prevents winnowing from accidentally extending the
         // lifetime of a variable.
@@ -1638,7 +1616,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 BuiltinCandidate { has_nested: false }
                 | DiscriminantKindCandidate
                 | PointeeCandidate
-                | ConstDestructCandidate(_),
+                | ConstDestructCandidate(_)
+                | TupleCandidate,
                 _,
             ) => true,
             (
@@ -1646,7 +1625,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 BuiltinCandidate { has_nested: false }
                 | DiscriminantKindCandidate
                 | PointeeCandidate
-                | ConstDestructCandidate(_),
+                | ConstDestructCandidate(_)
+                | TupleCandidate,
             ) => false,
 
             (ParamCandidate(other), ParamCandidate(victim)) => {
@@ -1693,9 +1673,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinCandidate { .. }
                 | TraitAliasCandidate(..)
                 | ObjectCandidate(_)
-                | ProjectionCandidate(_),
+                | ProjectionCandidate(..),
             ) => !is_global(cand),
-            (ObjectCandidate(_) | ProjectionCandidate(_), ParamCandidate(ref cand)) => {
+            (ObjectCandidate(_) | ProjectionCandidate(..), ParamCandidate(ref cand)) => {
                 // Prefer these to a global where-clause bound
                 // (see issue #50825).
                 is_global(cand)
@@ -1717,20 +1697,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 is_global(cand) && other.evaluation.must_apply_modulo_regions()
             }
 
-            (ProjectionCandidate(i), ProjectionCandidate(j))
+            (ProjectionCandidate(i, _), ProjectionCandidate(j, _))
             | (ObjectCandidate(i), ObjectCandidate(j)) => {
                 // Arbitrarily pick the lower numbered candidate for backwards
                 // compatibility reasons. Don't let this affect inference.
                 i < j && !needs_infer
             }
-            (ObjectCandidate(_), ProjectionCandidate(_))
-            | (ProjectionCandidate(_), ObjectCandidate(_)) => {
+            (ObjectCandidate(_), ProjectionCandidate(..))
+            | (ProjectionCandidate(..), ObjectCandidate(_)) => {
                 bug!("Have both object and projection candidate")
             }
 
             // Arbitrarily give projection and object candidates priority.
             (
-                ObjectCandidate(_) | ProjectionCandidate(_),
+                ObjectCandidate(_) | ProjectionCandidate(..),
                 ImplCandidate(..)
                 | ClosureCandidate
                 | GeneratorCandidate
@@ -1752,7 +1732,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { .. }
                 | TraitAliasCandidate(..),
-                ObjectCandidate(_) | ProjectionCandidate(_),
+                ObjectCandidate(_) | ProjectionCandidate(..),
             ) => false,
 
             (&ImplCandidate(other_def), &ImplCandidate(victim_def)) => {
@@ -1871,6 +1851,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::Array(..)
             | ty::Closure(..)
             | ty::Never
+            | ty::Dynamic(_, _, ty::DynStar)
             | ty::Error(_) => {
                 // safe for everything
                 Where(ty::Binder::dummy(Vec::new()))
@@ -1937,8 +1918,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             ty::Dynamic(..)
             | ty::Str
             | ty::Slice(..)
-            | ty::Generator(..)
-            | ty::GeneratorWitness(..)
+            | ty::Generator(_, _, hir::Movability::Static)
             | ty::Foreign(..)
             | ty::Ref(_, _, hir::Mutability::Mut) => None,
 
@@ -1947,6 +1927,43 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 Where(obligation.predicate.rebind(tys.iter().collect()))
             }
 
+            ty::Generator(_, substs, hir::Movability::Movable) => {
+                if self.tcx().features().generator_clone {
+                    let resolved_upvars =
+                        self.infcx.shallow_resolve(substs.as_generator().tupled_upvars_ty());
+                    let resolved_witness =
+                        self.infcx.shallow_resolve(substs.as_generator().witness());
+                    if resolved_upvars.is_ty_var() || resolved_witness.is_ty_var() {
+                        // Not yet resolved.
+                        Ambiguous
+                    } else {
+                        let all = substs
+                            .as_generator()
+                            .upvar_tys()
+                            .chain(iter::once(substs.as_generator().witness()))
+                            .collect::<Vec<_>>();
+                        Where(obligation.predicate.rebind(all))
+                    }
+                } else {
+                    None
+                }
+            }
+
+            ty::GeneratorWitness(binder) => {
+                let witness_tys = binder.skip_binder();
+                for witness_ty in witness_tys.iter() {
+                    let resolved = self.infcx.shallow_resolve(witness_ty);
+                    if resolved.is_ty_var() {
+                        return Ambiguous;
+                    }
+                }
+                // (*) binder moved here
+                let all_vars = self.tcx().mk_bound_variable_kinds(
+                    obligation.predicate.bound_vars().iter().chain(binder.bound_vars().iter()),
+                );
+                Where(ty::Binder::bind_with_vars(witness_tys.to_vec(), all_vars))
+            }
+
             ty::Closure(_, substs) => {
                 // (*) binder moved here
                 let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
@@ -2153,7 +2170,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
     }
 
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     fn match_impl(
         &mut self,
         impl_def_id: DefId,
@@ -2194,17 +2211,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .at(&cause, obligation.param_env)
             .define_opaque_types(false)
             .eq(placeholder_obligation_trait_ref, impl_trait_ref)
-            .map_err(|e| debug!("match_impl: failed eq_trait_refs due to `{}`", e))?;
+            .map_err(|e| debug!("match_impl: failed eq_trait_refs due to `{e}`"))?;
         nested_obligations.extend(obligations);
 
         if !self.intercrate
             && self.tcx().impl_polarity(impl_def_id) == ty::ImplPolarity::Reservation
         {
-            debug!("match_impl: reservation impls only apply in intercrate mode");
+            debug!("reservation impls only apply in intercrate mode");
             return Err(());
         }
 
-        debug!(?impl_substs, ?nested_obligations, "match_impl: success");
         Ok(Normalized { value: impl_substs, obligations: nested_obligations })
     }
 
@@ -2335,7 +2351,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     /// impl or trait. The obligations are substituted and fully
     /// normalized. This is used when confirming an impl or default
     /// impl.
-    #[tracing::instrument(level = "debug", skip(self, cause, param_env))]
+    #[instrument(level = "debug", skip(self, cause, param_env))]
     fn impl_or_trait_obligations(
         &mut self,
         cause: &ObligationCause<'tcx>,
diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
index 0f76fef0eee2..56a88749c46a 100644
--- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
@@ -12,14 +12,15 @@
 pub mod specialization_graph;
 use specialization_graph::GraphExt;
 
+use crate::errors::NegativePositiveConflict;
 use crate::infer::{InferCtxt, InferOk, TyCtxtInferExt};
 use crate::traits::select::IntercrateAmbiguityCause;
 use crate::traits::{self, coherence, FutureCompatOverlapErrorKind, ObligationCause};
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_errors::{struct_span_err, EmissionGuarantee, LintDiagnosticBuilder};
 use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::{self, ImplSubject, TyCtxt};
+use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_session::lint::builtin::COHERENCE_LEAK_CHECK;
 use rustc_session::lint::builtin::ORDER_DEPENDENT_TRAIT_OBJECTS;
 use rustc_span::{Span, DUMMY_SP};
@@ -327,35 +328,13 @@ fn report_negative_positive_conflict(
     positive_impl_def_id: DefId,
     sg: &mut specialization_graph::Graph,
 ) {
-    let impl_span = tcx.def_span(local_impl_def_id);
-
-    let mut err = struct_span_err!(
-        tcx.sess,
-        impl_span,
-        E0751,
-        "found both positive and negative implementation of trait `{}`{}:",
-        overlap.trait_desc,
-        overlap.self_desc.clone().map_or_else(String::new, |ty| format!(" for type `{}`", ty))
-    );
-
-    match tcx.span_of_impl(negative_impl_def_id) {
-        Ok(span) => {
-            err.span_label(span, "negative implementation here");
-        }
-        Err(cname) => {
-            err.note(&format!("negative implementation in crate `{}`", cname));
-        }
-    }
-
-    match tcx.span_of_impl(positive_impl_def_id) {
-        Ok(span) => {
-            err.span_label(span, "positive implementation here");
-        }
-        Err(cname) => {
-            err.note(&format!("positive implementation in crate `{}`", cname));
-        }
-    }
-
+    let mut err = tcx.sess.create_err(NegativePositiveConflict {
+        impl_span: tcx.def_span(local_impl_def_id),
+        trait_desc: &overlap.trait_desc,
+        self_desc: &overlap.self_desc,
+        negative_impl_span: tcx.span_of_impl(negative_impl_def_id),
+        positive_impl_span: tcx.span_of_impl(positive_impl_def_id),
+    });
     sg.has_errored = Some(err.emit());
 }
 
diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs
index 0f5dff01c662..5206e9f649bb 100644
--- a/compiler/rustc_trait_selection/src/traits/util.rs
+++ b/compiler/rustc_trait_selection/src/traits/util.rs
@@ -5,8 +5,8 @@ use smallvec::SmallVec;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::subst::{GenericArg, Subst, SubstsRef};
 use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{GenericArg, SubstsRef};
 
 use super::{Normalized, Obligation, ObligationCause, PredicateObligation, SelectionContext};
 pub use rustc_infer::traits::{self, util::*};
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index 4bd179d23913..9722b48a68ab 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -101,6 +101,7 @@ pub fn trait_obligations<'a, 'tcx>(
     wf.normalize(infcx)
 }
 
+#[instrument(skip(infcx), ret)]
 pub fn predicate_obligations<'a, 'tcx>(
     infcx: &InferCtxt<'a, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -129,9 +130,9 @@ pub fn predicate_obligations<'a, 'tcx>(
         }
         ty::PredicateKind::Projection(t) => {
             wf.compute_projection(t.projection_ty);
-            wf.compute(match t.term {
-                ty::Term::Ty(ty) => ty.into(),
-                ty::Term::Const(c) => c.into(),
+            wf.compute(match t.term.unpack() {
+                ty::TermKind::Ty(ty) => ty.into(),
+                ty::TermKind::Const(c) => c.into(),
             })
         }
         ty::PredicateKind::WellFormed(arg) => {
@@ -391,7 +392,8 @@ impl<'tcx> WfPredicates<'tcx> {
         //     `i32: Clone`
         //     `i32: Copy`
         // ]
-        let obligations = self.nominal_obligations(data.item_def_id, data.substs);
+        // Projection types do not require const predicates.
+        let obligations = self.nominal_obligations_without_const(data.item_def_id, data.substs);
         self.out.extend(obligations);
 
         let tcx = self.tcx();
@@ -434,11 +436,13 @@ impl<'tcx> WfPredicates<'tcx> {
     }
 
     /// Pushes all the predicates needed to validate that `ty` is WF into `out`.
+    #[instrument(level = "debug", skip(self))]
     fn compute(&mut self, arg: GenericArg<'tcx>) {
         let mut walker = arg.walk();
         let param_env = self.param_env;
         let depth = self.recursion_depth;
         while let Some(arg) = walker.next() {
+            debug!(?arg, ?self.out);
             let ty = match arg.unpack() {
                 GenericArgKind::Type(ty) => ty,
 
@@ -453,7 +457,7 @@ impl<'tcx> WfPredicates<'tcx> {
                             self.out.extend(obligations);
 
                             let predicate =
-                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv.shrink()))
+                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv))
                                     .to_predicate(self.tcx());
                             let cause = self.cause(traits::WellFormed(None));
                             self.out.push(traits::Obligation::with_depth(
@@ -488,6 +492,8 @@ impl<'tcx> WfPredicates<'tcx> {
                 }
             };
 
+            debug!("wf bounds for ty={:?} ty.kind={:#?}", ty, ty.kind());
+
             match *ty.kind() {
                 ty::Bool
                 | ty::Char
@@ -634,7 +640,7 @@ impl<'tcx> WfPredicates<'tcx> {
                     }
                 }
 
-                ty::Dynamic(data, r) => {
+                ty::Dynamic(data, r, _) => {
                     // WfObject
                     //
                     // Here, we defer WF checking due to higher-ranked
@@ -686,6 +692,8 @@ impl<'tcx> WfPredicates<'tcx> {
                     ));
                 }
             }
+
+            debug!(?self.out);
         }
     }
 
@@ -841,7 +849,7 @@ pub fn object_region_bounds<'tcx>(
 ///
 /// Requires that trait definitions have been processed so that we can
 /// elaborate predicates and walk supertraits.
-#[instrument(skip(tcx, predicates), level = "debug")]
+#[instrument(skip(tcx, predicates), level = "debug", ret)]
 pub(crate) fn required_region_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
     erased_self_ty: Ty<'tcx>,
diff --git a/compiler/rustc_traits/src/chalk/db.rs b/compiler/rustc_traits/src/chalk/db.rs
index ff5ca0cbcb7b..0de28b826616 100644
--- a/compiler/rustc_traits/src/chalk/db.rs
+++ b/compiler/rustc_traits/src/chalk/db.rs
@@ -7,8 +7,8 @@
 //! `crate::chalk::lowering` (to lower rustc types into Chalk types).
 
 use rustc_middle::traits::ChalkRustInterner as RustInterner;
-use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::{self, AssocKind, EarlyBinder, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable};
+use rustc_middle::ty::{InternalSubsts, SubstsRef};
 
 use rustc_ast::ast;
 use rustc_attr as attr;
diff --git a/compiler/rustc_traits/src/chalk/lowering.rs b/compiler/rustc_traits/src/chalk/lowering.rs
index c7c604e14e3e..45d5ea93d547 100644
--- a/compiler/rustc_traits/src/chalk/lowering.rs
+++ b/compiler/rustc_traits/src/chalk/lowering.rs
@@ -191,7 +191,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> for ty::Predi
                 GenericArgKind::Const(..) => {
                     chalk_ir::GoalData::All(chalk_ir::Goals::empty(interner))
                 }
-                GenericArgKind::Lifetime(lt) => bug!("unexpect well formed predicate: {:?}", lt),
+                GenericArgKind::Lifetime(lt) => bug!("unexpected well formed predicate: {:?}", lt),
             },
 
             ty::PredicateKind::ObjectSafe(t) => chalk_ir::GoalData::DomainGoal(
@@ -326,7 +326,8 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::Ty<RustInterner<'tcx>>> for Ty<'tcx> {
                     )),
                 })
             }
-            ty::Dynamic(predicates, region) => chalk_ir::TyKind::Dyn(chalk_ir::DynTy {
+            // FIXME(dyn-star): handle the dynamic kind (dyn or dyn*)
+            ty::Dynamic(predicates, region, _kind) => chalk_ir::TyKind::Dyn(chalk_ir::DynTy {
                 bounds: predicates.lower_into(interner),
                 lifetime: region.lower_into(interner),
             }),
@@ -485,10 +486,6 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::Lifetime<RustInterner<'tcx>>> for Region<'t
                 })
                 .intern(interner)
             }
-            ty::ReEmpty(ui) => {
-                chalk_ir::LifetimeData::Empty(chalk_ir::UniverseIndex { counter: ui.index() })
-                    .intern(interner)
-            }
             ty::ReErased => chalk_ir::LifetimeData::Erased.intern(interner),
         }
     }
@@ -510,8 +507,8 @@ impl<'tcx> LowerInto<'tcx, Region<'tcx>> for &chalk_ir::Lifetime<RustInterner<'t
                 name: ty::BoundRegionKind::BrAnon(p.idx as u32),
             }),
             chalk_ir::LifetimeData::Static => return interner.tcx.lifetimes.re_static,
-            chalk_ir::LifetimeData::Empty(ui) => {
-                ty::ReEmpty(ty::UniverseIndex::from_usize(ui.counter))
+            chalk_ir::LifetimeData::Empty(_) => {
+                bug!("Chalk should not have been passed an empty lifetime.")
             }
             chalk_ir::LifetimeData::Erased => return interner.tcx.lifetimes.re_erased,
             chalk_ir::LifetimeData::Phantom(void, _) => match *void {},
diff --git a/compiler/rustc_traits/src/dropck_outlives.rs b/compiler/rustc_traits/src/dropck_outlives.rs
index a20de08b4eff..7fb7c689550d 100644
--- a/compiler/rustc_traits/src/dropck_outlives.rs
+++ b/compiler/rustc_traits/src/dropck_outlives.rs
@@ -4,7 +4,7 @@ use rustc_infer::infer::canonical::{Canonical, QueryResponse};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::TraitEngineExt as _;
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
+use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, EarlyBinder, ParamEnvAnd, Ty, TyCtxt};
 use rustc_span::source_map::{Span, DUMMY_SP};
 use rustc_trait_selection::traits::query::dropck_outlives::trivial_dropck_outlives;
diff --git a/compiler/rustc_traits/src/implied_outlives_bounds.rs b/compiler/rustc_traits/src/implied_outlives_bounds.rs
index e3e78f70b15e..32aca4a8a3f9 100644
--- a/compiler/rustc_traits/src/implied_outlives_bounds.rs
+++ b/compiler/rustc_traits/src/implied_outlives_bounds.rs
@@ -49,7 +49,8 @@ fn compute_implied_outlives_bounds<'tcx>(
     let mut checked_wf_args = rustc_data_structures::fx::FxHashSet::default();
     let mut wf_args = vec![ty.into()];
 
-    let mut implied_bounds = vec![];
+    let mut outlives_bounds: Vec<ty::OutlivesPredicate<ty::GenericArg<'tcx>, ty::Region<'tcx>>> =
+        vec![];
 
     let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new(tcx);
 
@@ -65,30 +66,17 @@ fn compute_implied_outlives_bounds<'tcx>(
         // than the ultimate set. (Note: normally there won't be
         // unresolved inference variables here anyway, but there might be
         // during typeck under some circumstances.)
+        //
+        // FIXME(@lcnr): It's not really "always fine", having fewer implied
+        // bounds can be backward incompatible, e.g. #101951 was caused by
+        // us not dealing with inference vars in `TypeOutlives` predicates.
         let obligations = wf::obligations(infcx, param_env, hir::CRATE_HIR_ID, 0, arg, DUMMY_SP)
             .unwrap_or_default();
 
-        // N.B., all of these predicates *ought* to be easily proven
-        // true. In fact, their correctness is (mostly) implied by
-        // other parts of the program. However, in #42552, we had
-        // an annoying scenario where:
-        //
-        // - Some `T::Foo` gets normalized, resulting in a
-        //   variable `_1` and a `T: Trait<Foo=_1>` constraint
-        //   (not sure why it couldn't immediately get
-        //   solved). This result of `_1` got cached.
-        // - These obligations were dropped on the floor here,
-        //   rather than being registered.
-        // - Then later we would get a request to normalize
-        //   `T::Foo` which would result in `_1` being used from
-        //   the cache, but hence without the `T: Trait<Foo=_1>`
-        //   constraint. As a result, `_1` never gets resolved,
-        //   and we get an ICE (in dropck).
-        //
-        // Therefore, we register any predicates involving
-        // inference variables. We restrict ourselves to those
-        // involving inference variables both for efficiency and
-        // to avoids duplicate errors that otherwise show up.
+        // While these predicates should all be implied by other parts of
+        // the program, they are still relevant as they may constrain
+        // inference variables, which is necessary to add the correct
+        // implied bounds in some cases, mostly when dealing with projections.
         fulfill_cx.register_predicate_obligations(
             infcx,
             obligations.iter().filter(|o| o.predicate.has_infer_types_or_consts()).cloned(),
@@ -96,10 +84,10 @@ fn compute_implied_outlives_bounds<'tcx>(
 
         // From the full set of obligations, just filter down to the
         // region relationships.
-        implied_bounds.extend(obligations.into_iter().flat_map(|obligation| {
+        outlives_bounds.extend(obligations.into_iter().filter_map(|obligation| {
             assert!(!obligation.has_escaping_bound_vars());
             match obligation.predicate.kind().no_bound_vars() {
-                None => vec![],
+                None => None,
                 Some(pred) => match pred {
                     ty::PredicateKind::Trait(..)
                     | ty::PredicateKind::Subtype(..)
@@ -109,21 +97,18 @@ fn compute_implied_outlives_bounds<'tcx>(
                     | ty::PredicateKind::ObjectSafe(..)
                     | ty::PredicateKind::ConstEvaluatable(..)
                     | ty::PredicateKind::ConstEquate(..)
-                    | ty::PredicateKind::TypeWellFormedFromEnv(..) => vec![],
+                    | ty::PredicateKind::TypeWellFormedFromEnv(..) => None,
                     ty::PredicateKind::WellFormed(arg) => {
                         wf_args.push(arg);
-                        vec![]
+                        None
                     }
 
                     ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(r_a, r_b)) => {
-                        vec![OutlivesBound::RegionSubRegion(r_b, r_a)]
+                        Some(ty::OutlivesPredicate(r_a.into(), r_b))
                     }
 
                     ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_a, r_b)) => {
-                        let ty_a = infcx.resolve_vars_if_possible(ty_a);
-                        let mut components = smallvec![];
-                        push_outlives_components(tcx, ty_a, &mut components);
-                        implied_bounds_from_components(r_b, components)
+                        Some(ty::OutlivesPredicate(ty_a.into(), r_b))
                     }
                 },
             }
@@ -133,9 +118,27 @@ fn compute_implied_outlives_bounds<'tcx>(
     // Ensure that those obligations that we had to solve
     // get solved *here*.
     match fulfill_cx.select_all_or_error(infcx).as_slice() {
-        [] => Ok(implied_bounds),
-        _ => Err(NoSolution),
+        [] => (),
+        _ => return Err(NoSolution),
     }
+
+    // We lazily compute the outlives components as
+    // `select_all_or_error` constrains inference variables.
+    let implied_bounds = outlives_bounds
+        .into_iter()
+        .flat_map(|ty::OutlivesPredicate(a, r_b)| match a.unpack() {
+            ty::GenericArgKind::Lifetime(r_a) => vec![OutlivesBound::RegionSubRegion(r_b, r_a)],
+            ty::GenericArgKind::Type(ty_a) => {
+                let ty_a = infcx.resolve_vars_if_possible(ty_a);
+                let mut components = smallvec![];
+                push_outlives_components(tcx, ty_a, &mut components);
+                implied_bounds_from_components(r_b, components)
+            }
+            ty::GenericArgKind::Const(_) => unreachable!(),
+        })
+        .collect();
+
+    Ok(implied_bounds)
 }
 
 /// When we have an implied bound that `T: 'a`, we can further break
@@ -153,6 +156,9 @@ fn implied_bounds_from_components<'tcx>(
                 Component::Region(r) => Some(OutlivesBound::RegionSubRegion(sub_region, r)),
                 Component::Param(p) => Some(OutlivesBound::RegionSubParam(sub_region, p)),
                 Component::Projection(p) => Some(OutlivesBound::RegionSubProjection(sub_region, p)),
+                Component::Opaque(def_id, substs) => {
+                    Some(OutlivesBound::RegionSubOpaque(sub_region, def_id, substs))
+                }
                 Component::EscapingProjection(_) =>
                 // If the projection has escaping regions, don't
                 // try to infer any implied bounds even for its
diff --git a/compiler/rustc_traits/src/lib.rs b/compiler/rustc_traits/src/lib.rs
index 318e76c79f18..0da28737f69b 100644
--- a/compiler/rustc_traits/src/lib.rs
+++ b/compiler/rustc_traits/src/lib.rs
@@ -3,7 +3,6 @@
 
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
-#![feature(let_else)]
 #![recursion_limit = "256"]
 
 #[macro_use]
diff --git a/compiler/rustc_traits/src/type_op.rs b/compiler/rustc_traits/src/type_op.rs
index 60e9b88107dd..ff7d1ef00ccf 100644
--- a/compiler/rustc_traits/src/type_op.rs
+++ b/compiler/rustc_traits/src/type_op.rs
@@ -3,12 +3,12 @@ use rustc_hir::def_id::DefId;
 use rustc_infer::infer::at::ToTrace;
 use rustc_infer::infer::canonical::{Canonical, QueryResponse};
 use rustc_infer::infer::{DefiningAnchor, InferCtxt, TyCtxtInferExt};
-use rustc_infer::traits::TraitEngineExt as _;
+use rustc_infer::traits::{ObligationCauseCode, TraitEngineExt as _};
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::{GenericArg, Subst, UserSelfTy, UserSubsts};
 use rustc_middle::ty::{
     self, EarlyBinder, FnSig, Lift, PolyFnSig, Ty, TyCtxt, TypeFoldable, Variance,
 };
+use rustc_middle::ty::{GenericArg, UserSelfTy, UserSubsts};
 use rustc_middle::ty::{ParamEnv, ParamEnvAnd, Predicate, ToPredicate};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_trait_selection::infer::InferCtxtBuilderExt;
@@ -22,6 +22,7 @@ use rustc_trait_selection::traits::query::type_op::subtype::Subtype;
 use rustc_trait_selection::traits::query::{Fallible, NoSolution};
 use rustc_trait_selection::traits::{Normalized, Obligation, ObligationCause, TraitEngine};
 use std::fmt;
+use std::iter::zip;
 
 pub(crate) fn provide(p: &mut Providers) {
     *p = Providers {
@@ -61,28 +62,32 @@ pub fn type_op_ascribe_user_type_with_span<'a, 'tcx: 'a>(
         mir_ty, def_id, user_substs
     );
 
-    let mut cx = AscribeUserTypeCx { infcx, param_env, fulfill_cx };
-    cx.relate_mir_and_user_ty(mir_ty, def_id, user_substs, span)?;
+    let mut cx = AscribeUserTypeCx { infcx, param_env, span: span.unwrap_or(DUMMY_SP), fulfill_cx };
+    cx.relate_mir_and_user_ty(mir_ty, def_id, user_substs)?;
     Ok(())
 }
 
 struct AscribeUserTypeCx<'me, 'tcx> {
     infcx: &'me InferCtxt<'me, 'tcx>,
     param_env: ParamEnv<'tcx>,
+    span: Span,
     fulfill_cx: &'me mut dyn TraitEngine<'tcx>,
 }
 
 impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
     fn normalize<T>(&mut self, value: T) -> T
+    where
+        T: TypeFoldable<'tcx>,
+    {
+        self.normalize_with_cause(value, ObligationCause::misc(self.span, hir::CRATE_HIR_ID))
+    }
+
+    fn normalize_with_cause<T>(&mut self, value: T, cause: ObligationCause<'tcx>) -> T
     where
         T: TypeFoldable<'tcx>,
     {
         self.infcx
-            .partially_normalize_associated_types_in(
-                ObligationCause::misc(DUMMY_SP, hir::CRATE_HIR_ID),
-                self.param_env,
-                value,
-            )
+            .partially_normalize_associated_types_in(cause, self.param_env, value)
             .into_value_registering_obligations(self.infcx, self.fulfill_cx)
     }
 
@@ -91,18 +96,13 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
         T: ToTrace<'tcx>,
     {
         self.infcx
-            .at(&ObligationCause::dummy(), self.param_env)
+            .at(&ObligationCause::dummy_with_span(self.span), self.param_env)
             .relate(a, variance, b)?
             .into_value_registering_obligations(self.infcx, self.fulfill_cx);
         Ok(())
     }
 
-    fn prove_predicate(&mut self, predicate: Predicate<'tcx>, span: Option<Span>) {
-        let cause = if let Some(span) = span {
-            ObligationCause::dummy_with_span(span)
-        } else {
-            ObligationCause::dummy()
-        };
+    fn prove_predicate(&mut self, predicate: Predicate<'tcx>, cause: ObligationCause<'tcx>) {
         self.fulfill_cx.register_predicate_obligation(
             self.infcx,
             Obligation::new(cause, self.param_env, predicate),
@@ -126,7 +126,6 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
         mir_ty: Ty<'tcx>,
         def_id: DefId,
         user_substs: UserSubsts<'tcx>,
-        span: Option<Span>,
     ) -> Result<(), NoSolution> {
         let UserSubsts { user_self_ty, substs } = user_substs;
         let tcx = self.tcx();
@@ -145,10 +144,22 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
         // outlives" error messages.
         let instantiated_predicates =
             self.tcx().predicates_of(def_id).instantiate(self.tcx(), substs);
+
+        let cause = ObligationCause::dummy_with_span(self.span);
+
         debug!(?instantiated_predicates);
-        for instantiated_predicate in instantiated_predicates.predicates {
-            let instantiated_predicate = self.normalize(instantiated_predicate);
-            self.prove_predicate(instantiated_predicate, span);
+        for (instantiated_predicate, predicate_span) in
+            zip(instantiated_predicates.predicates, instantiated_predicates.spans)
+        {
+            let span = if self.span == DUMMY_SP { predicate_span } else { self.span };
+            let cause = ObligationCause::new(
+                span,
+                hir::CRATE_HIR_ID,
+                ObligationCauseCode::AscribeUserTypeProvePredicate(predicate_span),
+            );
+            let instantiated_predicate =
+                self.normalize_with_cause(instantiated_predicate, cause.clone());
+            self.prove_predicate(instantiated_predicate, cause);
         }
 
         if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
@@ -161,7 +172,7 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
             self.prove_predicate(
                 ty::Binder::dummy(ty::PredicateKind::WellFormed(impl_self_ty.into()))
                     .to_predicate(self.tcx()),
-                span,
+                cause.clone(),
             );
         }
 
@@ -178,7 +189,7 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
         // which...could happen with normalization...
         self.prove_predicate(
             ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into())).to_predicate(self.tcx()),
-            span,
+            cause,
         );
         Ok(())
     }
diff --git a/compiler/rustc_transmute/Cargo.toml b/compiler/rustc_transmute/Cargo.toml
index 9dc96e08a8e2..aa6fe7d24196 100644
--- a/compiler/rustc_transmute/Cargo.toml
+++ b/compiler/rustc_transmute/Cargo.toml
@@ -7,7 +7,8 @@ edition = "2021"
 
 [dependencies]
 tracing = "0.1"
-rustc_data_structures = { path = "../rustc_data_structures", optional = true}
+rustc_data_structures = { path = "../rustc_data_structures"}
+rustc_hir = { path = "../rustc_hir", optional = true}
 rustc_infer = { path = "../rustc_infer", optional = true}
 rustc_macros = { path = "../rustc_macros", optional = true}
 rustc_middle = { path = "../rustc_middle", optional = true}
@@ -17,7 +18,7 @@ rustc_target = { path = "../rustc_target", optional = true}
 [features]
 rustc = [
     "rustc_middle",
-    "rustc_data_structures",
+    "rustc_hir",
     "rustc_infer",
     "rustc_macros",
     "rustc_span",
diff --git a/compiler/rustc_transmute/src/layout/dfa.rs b/compiler/rustc_transmute/src/layout/dfa.rs
index b60ea6e7a24f..b8922696e306 100644
--- a/compiler/rustc_transmute/src/layout/dfa.rs
+++ b/compiler/rustc_transmute/src/layout/dfa.rs
@@ -104,7 +104,6 @@ where
     }
 
     #[instrument(level = "debug")]
-    #[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
     pub(crate) fn from_nfa(nfa: Nfa<R>) -> Self {
         let Nfa { transitions: nfa_transitions, start: nfa_start, accepting: nfa_accepting } = nfa;
 
diff --git a/compiler/rustc_transmute/src/layout/nfa.rs b/compiler/rustc_transmute/src/layout/nfa.rs
index f25e3c1fd8a3..c2bc47bc043a 100644
--- a/compiler/rustc_transmute/src/layout/nfa.rs
+++ b/compiler/rustc_transmute/src/layout/nfa.rs
@@ -119,8 +119,6 @@ where
 
         let mut transitions: Map<State, Map<Transition<R>, Set<State>>> = self.transitions;
 
-        // the iteration order doesn't matter
-        #[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
         for (source, transition) in other.transitions {
             let fix_state = |state| if state == other.start { self.accepting } else { state };
             let entry = transitions.entry(fix_state(source)).or_default();
@@ -142,8 +140,6 @@ where
 
         let mut transitions: Map<State, Map<Transition<R>, Set<State>>> = self.transitions.clone();
 
-        // the iteration order doesn't matter
-        #[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
         for (&(mut source), transition) in other.transitions.iter() {
             // if source is starting state of `other`, replace with starting state of `self`
             if source == other.start {
@@ -152,8 +148,6 @@ where
             let entry = transitions.entry(source).or_default();
             for (edge, destinations) in transition {
                 let entry = entry.entry(edge.clone()).or_default();
-                // the iteration order doesn't matter
-                #[cfg_attr(feature = "rustc", allow(rustc::potential_query_instability))]
                 for &(mut destination) in destinations {
                     // if dest is accepting state of `other`, replace with accepting state of `self`
                     if destination == other.accepting {
diff --git a/compiler/rustc_transmute/src/layout/tree.rs b/compiler/rustc_transmute/src/layout/tree.rs
index 93cab7ca5339..acd4fa63d782 100644
--- a/compiler/rustc_transmute/src/layout/tree.rs
+++ b/compiler/rustc_transmute/src/layout/tree.rs
@@ -317,7 +317,7 @@ pub(crate) mod rustc {
                             tcx,
                         )?,
                         AdtKind::Enum => {
-                            tracing::trace!(?adt_def, "treeifying enum");
+                            trace!(?adt_def, "treeifying enum");
                             let mut tree = Tree::uninhabited();
 
                             for (idx, discr) in adt_def.discriminants(tcx) {
@@ -381,7 +381,7 @@ pub(crate) mod rustc {
             let clamp =
                 |align: Align| align.clamp(min_align, max_align).bytes().try_into().unwrap();
 
-            let variant_span = tracing::trace_span!(
+            let variant_span = trace_span!(
                 "treeifying variant",
                 min_align = ?min_align,
                 max_align = ?max_align,
@@ -396,27 +396,27 @@ pub(crate) mod rustc {
 
             // The layout of the variant is prefixed by the discriminant, if any.
             if let Some(discr) = discr {
-                tracing::trace!(?discr, "treeifying discriminant");
+                trace!(?discr, "treeifying discriminant");
                 let discr_layout = alloc::Layout::from_size_align(
                     layout_summary.discriminant_size,
                     clamp(layout_summary.discriminant_align),
                 )
                 .unwrap();
-                tracing::trace!(?discr_layout, "computed discriminant layout");
+                trace!(?discr_layout, "computed discriminant layout");
                 variant_layout = variant_layout.extend(discr_layout).unwrap().0;
-                tree = tree.then(Self::from_disr(discr, tcx, layout_summary.discriminant_size));
+                tree = tree.then(Self::from_discr(discr, tcx, layout_summary.discriminant_size));
             }
 
             // Next come fields.
-            let fields_span = tracing::trace_span!("treeifying fields").entered();
+            let fields_span = trace_span!("treeifying fields").entered();
             for field_def in variant_def.fields.iter() {
                 let field_ty = field_def.ty(tcx, substs_ref);
-                let _span = tracing::trace_span!("treeifying field", field = ?field_ty).entered();
+                let _span = trace_span!("treeifying field", field = ?field_ty).entered();
 
                 // begin with the field's visibility
                 tree = tree.then(Self::def(Def::Field(field_def)));
 
-                // compute the field's layout charactaristics
+                // compute the field's layout characteristics
                 let field_layout = layout_of(tcx, field_ty)?.clamp_align(min_align, max_align);
 
                 // next comes the field's padding
@@ -434,7 +434,7 @@ pub(crate) mod rustc {
             drop(fields_span);
 
             // finally: padding
-            let padding_span = tracing::trace_span!("adding trailing padding").entered();
+            let padding_span = trace_span!("adding trailing padding").entered();
             let padding_needed = layout_summary.total_size - variant_layout.size();
             if padding_needed > 0 {
                 tree = tree.then(Self::padding(padding_needed));
@@ -444,11 +444,21 @@ pub(crate) mod rustc {
             Ok(tree)
         }
 
-        pub fn from_disr(discr: Discr<'tcx>, tcx: TyCtxt<'tcx>, size: usize) -> Self {
-            // FIXME(@jswrenn): I'm certain this is missing needed endian nuance.
-            let bytes = discr.val.to_ne_bytes();
-            let bytes = &bytes[..size];
-            Self::Seq(bytes.into_iter().copied().map(|b| Self::from_bits(b)).collect())
+        pub fn from_discr(discr: Discr<'tcx>, tcx: TyCtxt<'tcx>, size: usize) -> Self {
+            use rustc_target::abi::Endian;
+
+            let bytes: [u8; 16];
+            let bytes = match tcx.data_layout.endian {
+                Endian::Little => {
+                    bytes = discr.val.to_le_bytes();
+                    &bytes[..size]
+                }
+                Endian::Big => {
+                    bytes = discr.val.to_be_bytes();
+                    &bytes[bytes.len() - size..]
+                }
+            };
+            Self::Seq(bytes.iter().map(|&b| Self::from_bits(b)).collect())
         }
     }
 
@@ -467,7 +477,7 @@ pub(crate) mod rustc {
             layout.align().abi.bytes().try_into().unwrap(),
         )
         .unwrap();
-        tracing::trace!(?ty, ?layout, "computed layout for type");
+        trace!(?ty, ?layout, "computed layout for type");
         Ok(layout)
     }
 }
diff --git a/compiler/rustc_transmute/src/lib.rs b/compiler/rustc_transmute/src/lib.rs
index 89b1ce5abe9e..64cd70d36787 100644
--- a/compiler/rustc_transmute/src/lib.rs
+++ b/compiler/rustc_transmute/src/lib.rs
@@ -6,11 +6,7 @@
 #[macro_use]
 extern crate tracing;
 
-#[cfg(feature = "rustc")]
-pub(crate) use rustc_data_structures::fx::{FxHashMap as Map, FxHashSet as Set};
-
-#[cfg(not(feature = "rustc"))]
-pub(crate) use std::collections::{HashMap as Map, HashSet as Set};
+pub(crate) use rustc_data_structures::fx::{FxIndexMap as Map, FxIndexSet as Set};
 
 pub(crate) mod layout;
 pub(crate) mod maybe_transmutable;
@@ -19,8 +15,8 @@ pub(crate) mod maybe_transmutable;
 pub struct Assume {
     pub alignment: bool,
     pub lifetimes: bool,
+    pub safety: bool,
     pub validity: bool,
-    pub visibility: bool,
 }
 
 /// The type encodes answers to the question: "Are these types transmutable?"
@@ -62,11 +58,17 @@ pub enum Reason {
 
 #[cfg(feature = "rustc")]
 mod rustc {
+    use super::*;
+
+    use rustc_hir::lang_items::LangItem;
     use rustc_infer::infer::InferCtxt;
     use rustc_macros::{TypeFoldable, TypeVisitable};
     use rustc_middle::traits::ObligationCause;
     use rustc_middle::ty::Binder;
+    use rustc_middle::ty::Const;
+    use rustc_middle::ty::ParamEnv;
     use rustc_middle::ty::Ty;
+    use rustc_middle::ty::TyCtxt;
 
     /// The source and destination types of a transmutation.
     #[derive(TypeFoldable, TypeVisitable, Debug, Clone, Copy)]
@@ -106,6 +108,54 @@ mod rustc {
             .answer()
         }
     }
+
+    impl Assume {
+        /// Constructs an `Assume` from a given const-`Assume`.
+        pub fn from_const<'tcx>(
+            tcx: TyCtxt<'tcx>,
+            param_env: ParamEnv<'tcx>,
+            c: Const<'tcx>,
+        ) -> Self {
+            use rustc_middle::ty::ScalarInt;
+            use rustc_middle::ty::TypeVisitable;
+            use rustc_span::symbol::sym;
+
+            let c = c.eval(tcx, param_env);
+
+            if let Some(err) = c.error_reported() {
+                return Self { alignment: true, lifetimes: true, safety: true, validity: true };
+            }
+
+            let adt_def = c.ty().ty_adt_def().expect("The given `Const` must be an ADT.");
+
+            assert_eq!(
+                tcx.require_lang_item(LangItem::TransmuteOpts, None),
+                adt_def.did(),
+                "The given `Const` was not marked with the `{}` lang item.",
+                LangItem::TransmuteOpts.name(),
+            );
+
+            let variant = adt_def.non_enum_variant();
+            let fields = c.to_valtree().unwrap_branch();
+
+            let get_field = |name| {
+                let (field_idx, _) = variant
+                    .fields
+                    .iter()
+                    .enumerate()
+                    .find(|(_, field_def)| name == field_def.name)
+                    .expect(&format!("There were no fields named `{name}`."));
+                fields[field_idx].unwrap_leaf() == ScalarInt::TRUE
+            };
+
+            Self {
+                alignment: get_field(sym::alignment),
+                lifetimes: get_field(sym::lifetimes),
+                safety: get_field(sym::safety),
+                validity: get_field(sym::validity),
+            }
+        }
+    }
 }
 
 #[cfg(feature = "rustc")]
diff --git a/compiler/rustc_transmute/src/maybe_transmutable/mod.rs b/compiler/rustc_transmute/src/maybe_transmutable/mod.rs
index 076d922d1b72..1186eac37abd 100644
--- a/compiler/rustc_transmute/src/maybe_transmutable/mod.rs
+++ b/compiler/rustc_transmute/src/maybe_transmutable/mod.rs
@@ -105,12 +105,12 @@ where
     #[inline(always)]
     #[instrument(level = "debug", skip(self), fields(src = ?self.src, dst = ?self.dst))]
     pub(crate) fn answer(self) -> Answer<<C as QueryContext>::Ref> {
-        let assume_visibility = self.assume.visibility;
+        let assume_visibility = self.assume.safety;
         let query_or_answer = self.map_layouts(|src, dst, scope, context| {
             // Remove all `Def` nodes from `src`, without checking their visibility.
             let src = src.prune(&|def| true);
 
-            tracing::trace!(?src, "pruned src");
+            trace!(?src, "pruned src");
 
             // Remove all `Def` nodes from `dst`, additionally...
             let dst = if assume_visibility {
@@ -121,7 +121,7 @@ where
                 dst.prune(&|def| context.is_accessible_from(def, scope))
             };
 
-            tracing::trace!(?dst, "pruned dst");
+            trace!(?dst, "pruned dst");
 
             // Convert `src` from a tree-based representation to an NFA-based representation.
             // If the conversion fails because `src` is uninhabited, conclude that the transmutation
diff --git a/compiler/rustc_transmute/src/maybe_transmutable/query_context.rs b/compiler/rustc_transmute/src/maybe_transmutable/query_context.rs
index 9c2cf4c9a923..adab343ac98a 100644
--- a/compiler/rustc_transmute/src/maybe_transmutable/query_context.rs
+++ b/compiler/rustc_transmute/src/maybe_transmutable/query_context.rs
@@ -82,7 +82,7 @@ mod rustc {
                 false
             };
 
-            tracing::trace!(?ret, "ret");
+            trace!(?ret, "ret");
             ret
         }
 
diff --git a/compiler/rustc_transmute/src/maybe_transmutable/tests.rs b/compiler/rustc_transmute/src/maybe_transmutable/tests.rs
index d9d125687f65..4d5772a4f2ea 100644
--- a/compiler/rustc_transmute/src/maybe_transmutable/tests.rs
+++ b/compiler/rustc_transmute/src/maybe_transmutable/tests.rs
@@ -13,7 +13,7 @@ mod bool {
             layout::Tree::<Def, !>::bool(),
             layout::Tree::<Def, !>::bool(),
             (),
-            crate::Assume { alignment: false, lifetimes: false, validity: true, visibility: false },
+            crate::Assume { alignment: false, lifetimes: false, validity: true, safety: false },
             UltraMinimal,
         )
         .answer();
@@ -26,7 +26,7 @@ mod bool {
             layout::Dfa::<!>::bool(),
             layout::Dfa::<!>::bool(),
             (),
-            crate::Assume { alignment: false, lifetimes: false, validity: true, visibility: false },
+            crate::Assume { alignment: false, lifetimes: false, validity: true, safety: false },
             UltraMinimal,
         )
         .answer();
diff --git a/compiler/rustc_ty_utils/src/assoc.rs b/compiler/rustc_ty_utils/src/assoc.rs
index 515a73ead777..3e2553c425ed 100644
--- a/compiler/rustc_ty_utils/src/assoc.rs
+++ b/compiler/rustc_ty_utils/src/assoc.rs
@@ -42,7 +42,7 @@ fn impl_item_implementor_ids(tcx: TyCtxt<'_>, impl_id: DefId) -> FxHashMap<DefId
 fn associated_item(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AssocItem {
     let id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
     let parent_def_id = tcx.hir().get_parent_item(id);
-    let parent_item = tcx.hir().expect_item(parent_def_id);
+    let parent_item = tcx.hir().expect_item(parent_def_id.def_id);
     match parent_item.kind {
         hir::ItemKind::Impl(ref impl_) => {
             if let Some(impl_item_ref) =
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs
index 16c4d429129a..493ef3351135 100644
--- a/compiler/rustc_ty_utils/src/consts.rs
+++ b/compiler/rustc_ty_utils/src/consts.rs
@@ -155,9 +155,9 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                     return true;
                 }
 
-                match pat.kind.as_ref() {
+                match pat.kind {
                     thir::PatKind::Constant { value } => value.has_param_types_or_consts(),
-                    thir::PatKind::Range(thir::PatRange { lo, hi, .. }) => {
+                    thir::PatKind::Range(box thir::PatRange { lo, hi, .. }) => {
                         lo.has_param_types_or_consts() || hi.has_param_types_or_consts()
                     }
                     _ => false,
@@ -222,17 +222,6 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
         debug!("AbstractConstBuilder::build: body={:?}", &*self.body);
         self.recurse_build(self.body_id)?;
 
-        for n in self.nodes.iter() {
-            if let Node::Leaf(ct) = n {
-                if let ty::ConstKind::Unevaluated(ct) = ct.kind() {
-                    // `AbstractConst`s should not contain any promoteds as they require references which
-                    // are not allowed.
-                    assert_eq!(ct.promoted, None);
-                    assert_eq!(ct, self.tcx.erase_regions(ct));
-                }
-            }
-        }
-
         Ok(self.tcx.arena.alloc_from_iter(self.nodes.into_iter()))
     }
 
@@ -269,7 +258,8 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                 self.nodes.push(Node::Leaf(ty::Const::from_value(self.tcx, val, node.ty)))
             }
             &ExprKind::NamedConst { def_id, substs, user_ty: _ } => {
-                let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
+                let uneval =
+                    ty::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
 
                 let constant = self
                     .tcx
diff --git a/compiler/rustc_ty_utils/src/errors.rs b/compiler/rustc_ty_utils/src/errors.rs
index 3a8ef96c991f..753c474a34bc 100644
--- a/compiler/rustc_ty_utils/src/errors.rs
+++ b/compiler/rustc_ty_utils/src/errors.rs
@@ -1,16 +1,16 @@
 //! Errors emitted by ty_utils
 
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
+use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_middle::ty::Ty;
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ty_utils::needs_drop_overflow)]
 pub struct NeedsDropOverflow<'tcx> {
     pub query_ty: Ty<'tcx>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(ty_utils::generic_constant_too_complex)]
 #[help]
 pub struct GenericConstantTooComplex {
@@ -22,7 +22,7 @@ pub struct GenericConstantTooComplex {
     pub sub: GenericConstantTooComplexSub,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum GenericConstantTooComplexSub {
     #[label(ty_utils::borrow_not_supported)]
     BorrowNotSupported(#[primary_span] Span),
diff --git a/compiler/rustc_ty_utils/src/implied_bounds.rs b/compiler/rustc_ty_utils/src/implied_bounds.rs
index a77ea440aaae..f0d8c240ea58 100644
--- a/compiler/rustc_ty_utils/src/implied_bounds.rs
+++ b/compiler/rustc_ty_utils/src/implied_bounds.rs
@@ -51,6 +51,7 @@ fn assumed_wf_types<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ty::List<Ty
         | DefKind::AnonConst
         | DefKind::InlineConst
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Field
         | DefKind::LifetimeParam
         | DefKind::GlobalAsm
diff --git a/compiler/rustc_ty_utils/src/instance.rs b/compiler/rustc_ty_utils/src/instance.rs
index bd1d568cd9a0..05738b6c48ae 100644
--- a/compiler/rustc_ty_utils/src/instance.rs
+++ b/compiler/rustc_ty_utils/src/instance.rs
@@ -3,115 +3,11 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::traits::CodegenObligationError;
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{
-    self, Binder, Instance, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
-};
+use rustc_middle::ty::{self, Instance, TyCtxt, TypeVisitable};
 use rustc_span::{sym, DUMMY_SP};
 use rustc_trait_selection::traits;
 use traits::{translate_substs, Reveal};
 
-use rustc_data_structures::sso::SsoHashSet;
-use std::collections::btree_map::Entry;
-use std::collections::BTreeMap;
-use std::ops::ControlFlow;
-
-use tracing::debug;
-
-// FIXME(#86795): `BoundVarsCollector` here should **NOT** be used
-// outside of `resolve_associated_item`. It's just to address #64494,
-// #83765, and #85848 which are creating bound types/regions that lose
-// their `Binder` *unintentionally*.
-// It's ideal to remove `BoundVarsCollector` and just use
-// `ty::Binder::*` methods but we use this stopgap until we figure out
-// the "real" fix.
-struct BoundVarsCollector<'tcx> {
-    binder_index: ty::DebruijnIndex,
-    vars: BTreeMap<u32, ty::BoundVariableKind>,
-    // We may encounter the same variable at different levels of binding, so
-    // this can't just be `Ty`
-    visited: SsoHashSet<(ty::DebruijnIndex, Ty<'tcx>)>,
-}
-
-impl<'tcx> BoundVarsCollector<'tcx> {
-    fn new() -> Self {
-        BoundVarsCollector {
-            binder_index: ty::INNERMOST,
-            vars: BTreeMap::new(),
-            visited: SsoHashSet::default(),
-        }
-    }
-
-    fn into_vars(self, tcx: TyCtxt<'tcx>) -> &'tcx ty::List<ty::BoundVariableKind> {
-        let max = self.vars.iter().map(|(k, _)| *k).max().unwrap_or(0);
-        for i in 0..max {
-            if let None = self.vars.get(&i) {
-                panic!("Unknown variable: {:?}", i);
-            }
-        }
-
-        tcx.mk_bound_variable_kinds(self.vars.into_iter().map(|(_, v)| v))
-    }
-}
-
-impl<'tcx> TypeVisitor<'tcx> for BoundVarsCollector<'tcx> {
-    type BreakTy = ();
-
-    fn visit_binder<T: TypeVisitable<'tcx>>(
-        &mut self,
-        t: &Binder<'tcx, T>,
-    ) -> ControlFlow<Self::BreakTy> {
-        self.binder_index.shift_in(1);
-        let result = t.super_visit_with(self);
-        self.binder_index.shift_out(1);
-        result
-    }
-
-    fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-        if t.outer_exclusive_binder() < self.binder_index
-            || !self.visited.insert((self.binder_index, t))
-        {
-            return ControlFlow::CONTINUE;
-        }
-        match *t.kind() {
-            ty::Bound(debruijn, bound_ty) if debruijn == self.binder_index => {
-                match self.vars.entry(bound_ty.var.as_u32()) {
-                    Entry::Vacant(entry) => {
-                        entry.insert(ty::BoundVariableKind::Ty(bound_ty.kind));
-                    }
-                    Entry::Occupied(entry) => match entry.get() {
-                        ty::BoundVariableKind::Ty(_) => {}
-                        _ => bug!("Conflicting bound vars"),
-                    },
-                }
-            }
-
-            _ => (),
-        };
-
-        t.super_visit_with(self)
-    }
-
-    fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
-        match *r {
-            ty::ReLateBound(index, br) if index == self.binder_index => {
-                match self.vars.entry(br.var.as_u32()) {
-                    Entry::Vacant(entry) => {
-                        entry.insert(ty::BoundVariableKind::Region(br.kind));
-                    }
-                    Entry::Occupied(entry) => match entry.get() {
-                        ty::BoundVariableKind::Region(_) => {}
-                        _ => bug!("Conflicting bound vars"),
-                    },
-                }
-            }
-
-            _ => (),
-        };
-
-        r.super_visit_with(self)
-    }
-}
-
 fn resolve_instance<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: ty::ParamEnvAnd<'tcx, (DefId, SubstsRef<'tcx>)>,
@@ -203,19 +99,14 @@ fn resolve_associated_item<'tcx>(
 
     let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs);
 
-    // See FIXME on `BoundVarsCollector`.
-    let mut bound_vars_collector = BoundVarsCollector::new();
-    trait_ref.visit_with(&mut bound_vars_collector);
-    let trait_binder = ty::Binder::bind_with_vars(trait_ref, bound_vars_collector.into_vars(tcx));
-    let vtbl = match tcx.codegen_fulfill_obligation((param_env, trait_binder)) {
+    let vtbl = match tcx.codegen_select_candidate((param_env, ty::Binder::dummy(trait_ref))) {
         Ok(vtbl) => vtbl,
         Err(CodegenObligationError::Ambiguity) => {
             let reported = tcx.sess.delay_span_bug(
                 tcx.def_span(trait_item_id),
                 &format!(
-                    "encountered ambiguity selecting `{:?}` during codegen, presuming due to \
+                    "encountered ambiguity selecting `{trait_ref:?}` during codegen, presuming due to \
                      overflow or prior type error",
-                    trait_binder
                 ),
             );
             return Err(reported);
@@ -372,7 +263,10 @@ fn resolve_associated_item<'tcx>(
                     let is_copy = self_ty.is_copy_modulo_regions(tcx.at(DUMMY_SP), param_env);
                     match self_ty.kind() {
                         _ if is_copy => (),
-                        ty::Closure(..) | ty::Tuple(..) => {}
+                        ty::Generator(..)
+                        | ty::GeneratorWitness(..)
+                        | ty::Closure(..)
+                        | ty::Tuple(..) => {}
                         _ => return Ok(None),
                     };
 
@@ -397,7 +291,8 @@ fn resolve_associated_item<'tcx>(
         | traits::ImplSource::DiscriminantKind(..)
         | traits::ImplSource::Pointee(..)
         | traits::ImplSource::TraitUpcasting(_)
-        | traits::ImplSource::ConstDestruct(_) => None,
+        | traits::ImplSource::ConstDestruct(_)
+        | traits::ImplSource::Tuple => None,
     })
 }
 
diff --git a/compiler/rustc_ty_utils/src/lib.rs b/compiler/rustc_ty_utils/src/lib.rs
index 6931b15b1ba5..10c18789f747 100644
--- a/compiler/rustc_ty_utils/src/lib.rs
+++ b/compiler/rustc_ty_utils/src/lib.rs
@@ -6,7 +6,6 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
 #![feature(never_type)]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_ty_utils/src/needs_drop.rs b/compiler/rustc_ty_utils/src/needs_drop.rs
index ab5a3d8ae489..ba987c6f7631 100644
--- a/compiler/rustc_ty_utils/src/needs_drop.rs
+++ b/compiler/rustc_ty_utils/src/needs_drop.rs
@@ -2,7 +2,6 @@
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::util::{needs_drop_components, AlwaysRequiresDrop};
 use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt};
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index acfeefb4d12d..f7db39dfec3b 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -1,7 +1,6 @@
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, Binder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt};
 use rustc_trait_selection::traits;
 
@@ -104,7 +103,6 @@ fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AdtSizedConstrain
 }
 
 /// See `ParamEnv` struct definition for details.
-#[instrument(level = "debug", skip(tcx))]
 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
     // The param_env of an impl Trait type is its defining function's param_env
     if let Some(parent) = ty::is_impl_trait_defn(tcx, def_id) {
@@ -390,7 +388,7 @@ fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
 
     let self_ty = trait_ref.self_ty();
     let self_ty_matches = match self_ty.kind() {
-        ty::Dynamic(ref data, re) if re.is_static() => data.principal().is_none(),
+        ty::Dynamic(ref data, re, _) if re.is_static() => data.principal().is_none(),
         _ => false,
     };
 
@@ -410,7 +408,6 @@ fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
 }
 
 /// Don't call this directly: use ``tcx.conservative_is_privately_uninhabited`` instead.
-#[instrument(level = "debug", skip(tcx))]
 pub fn conservative_is_privately_uninhabited_raw<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env_and: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,
diff --git a/compiler/rustc_type_ir/src/lib.rs b/compiler/rustc_type_ir/src/lib.rs
index 5488bca8f471..da30344ef7ec 100644
--- a/compiler/rustc_type_ir/src/lib.rs
+++ b/compiler/rustc_type_ir/src/lib.rs
@@ -23,6 +23,9 @@ pub mod sty;
 pub use codec::*;
 pub use sty::*;
 
+/// Needed so we can use #[derive(HashStable_Generic)]
+pub trait HashStableContext {}
+
 pub trait Interner {
     type AdtDef: Clone + Debug + Hash + PartialEq + Eq + PartialOrd + Ord;
     type SubstsRef: Clone + Debug + Hash + PartialEq + Eq + PartialOrd + Ord;
@@ -295,6 +298,7 @@ rustc_index::newtype_index! {
     /// is the outer fn.
     ///
     /// [dbi]: https://en.wikipedia.org/wiki/De_Bruijn_index
+    #[derive(HashStable_Generic)]
     pub struct DebruijnIndex {
         DEBUG_FORMAT = "DebruijnIndex({})",
         const INNERMOST = 0,
@@ -366,7 +370,7 @@ impl DebruijnIndex {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-#[derive(Encodable, Decodable)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
 pub enum IntTy {
     Isize,
     I8,
@@ -413,7 +417,7 @@ impl IntTy {
 }
 
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Debug)]
-#[derive(Encodable, Decodable)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
 pub enum UintTy {
     Usize,
     U8,
@@ -460,7 +464,7 @@ impl UintTy {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
-#[derive(Encodable, Decodable)]
+#[derive(Encodable, Decodable, HashStable_Generic)]
 pub enum FloatTy {
     F32,
     F64,
@@ -597,7 +601,7 @@ impl UnifyKey for FloatVid {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Decodable, Encodable, Hash)]
+#[derive(Copy, Clone, PartialEq, Decodable, Encodable, Hash, HashStable_Generic)]
 #[rustc_pass_by_value]
 pub enum Variance {
     Covariant,     // T<A> <: T<B> iff A <: B -- e.g., function return type
@@ -666,30 +670,6 @@ impl Variance {
     }
 }
 
-impl<CTX> HashStable<CTX> for DebruijnIndex {
-    fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        self.as_u32().hash_stable(ctx, hasher);
-    }
-}
-
-impl<CTX> HashStable<CTX> for IntTy {
-    fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        discriminant(self).hash_stable(ctx, hasher);
-    }
-}
-
-impl<CTX> HashStable<CTX> for UintTy {
-    fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        discriminant(self).hash_stable(ctx, hasher);
-    }
-}
-
-impl<CTX> HashStable<CTX> for FloatTy {
-    fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        discriminant(self).hash_stable(ctx, hasher);
-    }
-}
-
 impl<CTX> HashStable<CTX> for InferTy {
     fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
         use InferTy::*;
@@ -703,12 +683,6 @@ impl<CTX> HashStable<CTX> for InferTy {
     }
 }
 
-impl<CTX> HashStable<CTX> for Variance {
-    fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        discriminant(self).hash_stable(ctx, hasher);
-    }
-}
-
 impl fmt::Debug for IntVarValue {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
@@ -811,6 +785,7 @@ rustc_index::newtype_index! {
     /// declared, but a type name in a non-zero universe is a placeholder
     /// type -- an idealized representative of "types in general" that we
     /// use for checking generic functions.
+    #[derive(HashStable_Generic)]
     pub struct UniverseIndex {
         DEBUG_FORMAT = "U{}",
     }
@@ -850,9 +825,3 @@ impl UniverseIndex {
         self.private < other.private
     }
 }
-
-impl<CTX> HashStable<CTX> for UniverseIndex {
-    fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
-        self.private.hash_stable(ctx, hasher);
-    }
-}
diff --git a/compiler/rustc_type_ir/src/sty.rs b/compiler/rustc_type_ir/src/sty.rs
index 74737e30bb4d..6d54924e515f 100644
--- a/compiler/rustc_type_ir/src/sty.rs
+++ b/compiler/rustc_type_ir/src/sty.rs
@@ -5,12 +5,12 @@ use std::{fmt, hash};
 
 use crate::DebruijnIndex;
 use crate::FloatTy;
+use crate::HashStableContext;
 use crate::IntTy;
 use crate::Interner;
 use crate::TyDecoder;
 use crate::TyEncoder;
 use crate::UintTy;
-use crate::UniverseIndex;
 
 use self::RegionKind::*;
 use self::TyKind::*;
@@ -18,6 +18,34 @@ use self::TyKind::*;
 use rustc_data_structures::stable_hasher::HashStable;
 use rustc_serialize::{Decodable, Decoder, Encodable};
 
+/// Specifies how a trait object is represented.
+#[derive(
+    Clone,
+    Copy,
+    PartialEq,
+    Eq,
+    PartialOrd,
+    Ord,
+    Hash,
+    Debug,
+    Encodable,
+    Decodable,
+    HashStable_Generic
+)]
+pub enum DynKind {
+    /// An unsized `dyn Trait` object
+    Dyn,
+    /// A sized `dyn* Trait` object
+    ///
+    /// These objects are represented as a `(data, vtable)` pair where `data` is a ptr-sized value
+    /// (often a pointer to the real object, but not necessarily) and `vtable` is a pointer to
+    /// the vtable for `dyn* Trait`. The representation is essentially the same as `&dyn Trait`
+    /// or similar, but the drop function included in the vtable is responsible for freeing the
+    /// underlying storage if needed. This allows a `dyn*` object to be treated agnostically with
+    /// respect to whether it points to a `Box<T>`, `Rc<T>`, etc.
+    DynStar,
+}
+
 /// Defines the kinds of types used by the type system.
 ///
 /// Types written by the user start out as `hir::TyKind` and get
@@ -95,7 +123,7 @@ pub enum TyKind<I: Interner> {
     FnPtr(I::PolyFnSig),
 
     /// A trait object. Written as `dyn for<'b> Trait<'b, Assoc = u32> + Send + 'a`.
-    Dynamic(I::ListBinderExistentialPredicate, I::Region),
+    Dynamic(I::ListBinderExistentialPredicate, I::Region, DynKind),
 
     /// The anonymous type of a closure. Used to represent the type of `|a| a`.
     ///
@@ -218,7 +246,7 @@ const fn tykind_discriminant<I: Interner>(value: &TyKind<I>) -> usize {
         Ref(_, _, _) => 11,
         FnDef(_, _) => 12,
         FnPtr(_) => 13,
-        Dynamic(_, _) => 14,
+        Dynamic(..) => 14,
         Closure(_, _) => 15,
         Generator(_, _, _) => 16,
         GeneratorWitness(_) => 17,
@@ -252,7 +280,7 @@ impl<I: Interner> Clone for TyKind<I> {
             Ref(r, t, m) => Ref(r.clone(), t.clone(), m.clone()),
             FnDef(d, s) => FnDef(d.clone(), s.clone()),
             FnPtr(s) => FnPtr(s.clone()),
-            Dynamic(p, r) => Dynamic(p.clone(), r.clone()),
+            Dynamic(p, r, repr) => Dynamic(p.clone(), r.clone(), repr.clone()),
             Closure(d, s) => Closure(d.clone(), s.clone()),
             Generator(d, s, m) => Generator(d.clone(), s.clone(), m.clone()),
             GeneratorWitness(g) => GeneratorWitness(g.clone()),
@@ -297,9 +325,10 @@ impl<I: Interner> PartialEq for TyKind<I> {
                     __self_0 == __arg_1_0 && __self_1 == __arg_1_1
                 }
                 (&FnPtr(ref __self_0), &FnPtr(ref __arg_1_0)) => __self_0 == __arg_1_0,
-                (&Dynamic(ref __self_0, ref __self_1), &Dynamic(ref __arg_1_0, ref __arg_1_1)) => {
-                    __self_0 == __arg_1_0 && __self_1 == __arg_1_1
-                }
+                (
+                    &Dynamic(ref __self_0, ref __self_1, ref self_repr),
+                    &Dynamic(ref __arg_1_0, ref __arg_1_1, ref arg_repr),
+                ) => __self_0 == __arg_1_0 && __self_1 == __arg_1_1 && self_repr == arg_repr,
                 (&Closure(ref __self_0, ref __self_1), &Closure(ref __arg_1_0, ref __arg_1_1)) => {
                     __self_0 == __arg_1_0 && __self_1 == __arg_1_1
                 }
@@ -384,12 +413,16 @@ impl<I: Interner> Ord for TyKind<I> {
                     }
                 }
                 (&FnPtr(ref __self_0), &FnPtr(ref __arg_1_0)) => Ord::cmp(__self_0, __arg_1_0),
-                (&Dynamic(ref __self_0, ref __self_1), &Dynamic(ref __arg_1_0, ref __arg_1_1)) => {
-                    match Ord::cmp(__self_0, __arg_1_0) {
-                        Ordering::Equal => Ord::cmp(__self_1, __arg_1_1),
+                (
+                    &Dynamic(ref __self_0, ref __self_1, ref self_repr),
+                    &Dynamic(ref __arg_1_0, ref __arg_1_1, ref arg_repr),
+                ) => match Ord::cmp(__self_0, __arg_1_0) {
+                    Ordering::Equal => match Ord::cmp(__self_1, __arg_1_1) {
+                        Ordering::Equal => Ord::cmp(self_repr, arg_repr),
                         cmp => cmp,
-                    }
-                }
+                    },
+                    cmp => cmp,
+                },
                 (&Closure(ref __self_0, ref __self_1), &Closure(ref __arg_1_0, ref __arg_1_1)) => {
                     match Ord::cmp(__self_0, __arg_1_0) {
                         Ordering::Equal => Ord::cmp(__self_1, __arg_1_1),
@@ -492,10 +525,11 @@ impl<I: Interner> hash::Hash for TyKind<I> {
                 hash::Hash::hash(&tykind_discriminant(self), state);
                 hash::Hash::hash(__self_0, state)
             }
-            (&Dynamic(ref __self_0, ref __self_1),) => {
+            (&Dynamic(ref __self_0, ref __self_1, ref repr),) => {
                 hash::Hash::hash(&tykind_discriminant(self), state);
                 hash::Hash::hash(__self_0, state);
-                hash::Hash::hash(__self_1, state)
+                hash::Hash::hash(__self_1, state);
+                hash::Hash::hash(repr, state)
             }
             (&Closure(ref __self_0, ref __self_1),) => {
                 hash::Hash::hash(&tykind_discriminant(self), state);
@@ -570,7 +604,7 @@ impl<I: Interner> fmt::Debug for TyKind<I> {
             Ref(f0, f1, f2) => Formatter::debug_tuple_field3_finish(f, "Ref", f0, f1, f2),
             FnDef(f0, f1) => Formatter::debug_tuple_field2_finish(f, "FnDef", f0, f1),
             FnPtr(f0) => Formatter::debug_tuple_field1_finish(f, "FnPtr", f0),
-            Dynamic(f0, f1) => Formatter::debug_tuple_field2_finish(f, "Dynamic", f0, f1),
+            Dynamic(f0, f1, f2) => Formatter::debug_tuple_field3_finish(f, "Dynamic", f0, f1, f2),
             Closure(f0, f1) => Formatter::debug_tuple_field2_finish(f, "Closure", f0, f1),
             Generator(f0, f1, f2) => {
                 Formatter::debug_tuple_field3_finish(f, "Generator", f0, f1, f2)
@@ -659,9 +693,10 @@ where
             FnPtr(polyfnsig) => e.emit_enum_variant(disc, |e| {
                 polyfnsig.encode(e);
             }),
-            Dynamic(l, r) => e.emit_enum_variant(disc, |e| {
+            Dynamic(l, r, repr) => e.emit_enum_variant(disc, |e| {
                 l.encode(e);
                 r.encode(e);
+                repr.encode(e);
             }),
             Closure(def_id, substs) => e.emit_enum_variant(disc, |e| {
                 def_id.encode(e);
@@ -748,7 +783,7 @@ where
             11 => Ref(Decodable::decode(d), Decodable::decode(d), Decodable::decode(d)),
             12 => FnDef(Decodable::decode(d), Decodable::decode(d)),
             13 => FnPtr(Decodable::decode(d)),
-            14 => Dynamic(Decodable::decode(d), Decodable::decode(d)),
+            14 => Dynamic(Decodable::decode(d), Decodable::decode(d), Decodable::decode(d)),
             15 => Closure(Decodable::decode(d), Decodable::decode(d)),
             16 => Generator(Decodable::decode(d), Decodable::decode(d), Decodable::decode(d)),
             17 => GeneratorWitness(Decodable::decode(d)),
@@ -774,7 +809,7 @@ where
 
 // This is not a derived impl because a derive would require `I: HashStable`
 #[allow(rustc::usage_of_ty_tykind)]
-impl<CTX, I: Interner> HashStable<CTX> for TyKind<I>
+impl<CTX: HashStableContext, I: Interner> HashStable<CTX> for TyKind<I>
 where
     I::AdtDef: HashStable<CTX>,
     I::DefId: HashStable<CTX>,
@@ -845,9 +880,10 @@ where
             FnPtr(polyfnsig) => {
                 polyfnsig.hash_stable(__hcx, __hasher);
             }
-            Dynamic(l, r) => {
+            Dynamic(l, r, repr) => {
                 l.hash_stable(__hcx, __hasher);
                 r.hash_stable(__hcx, __hasher);
+                repr.hash_stable(__hcx, __hasher);
             }
             Closure(def_id, substs) => {
                 def_id.hash_stable(__hcx, __hasher);
@@ -1023,14 +1059,6 @@ pub enum RegionKind<I: Interner> {
     /// Should not exist outside of type inference.
     RePlaceholder(I::PlaceholderRegion),
 
-    /// Empty lifetime is for data that is never accessed.  We tag the
-    /// empty lifetime with a universe -- the idea is that we don't
-    /// want `exists<'a> { forall<'b> { 'b: 'a } }` to be satisfiable.
-    /// Therefore, the `'empty` in a universe `U` is less than all
-    /// regions visible from `U`, but not less than regions not visible
-    /// from `U`.
-    ReEmpty(UniverseIndex),
-
     /// Erased region, used by trait selection, in MIR and during codegen.
     ReErased,
 }
@@ -1046,8 +1074,7 @@ const fn regionkind_discriminant<I: Interner>(value: &RegionKind<I>) -> usize {
         ReStatic => 3,
         ReVar(_) => 4,
         RePlaceholder(_) => 5,
-        ReEmpty(_) => 6,
-        ReErased => 7,
+        ReErased => 6,
     }
 }
 
@@ -1072,7 +1099,6 @@ impl<I: Interner> Clone for RegionKind<I> {
             ReStatic => ReStatic,
             ReVar(a) => ReVar(a.clone()),
             RePlaceholder(a) => RePlaceholder(a.clone()),
-            ReEmpty(a) => ReEmpty(a.clone()),
             ReErased => ReErased,
         }
     }
@@ -1099,7 +1125,6 @@ impl<I: Interner> PartialEq for RegionKind<I> {
                 (&RePlaceholder(ref __self_0), &RePlaceholder(ref __arg_1_0)) => {
                     __self_0 == __arg_1_0
                 }
-                (&ReEmpty(ref __self_0), &ReEmpty(ref __arg_1_0)) => __self_0 == __arg_1_0,
                 (&ReErased, &ReErased) => true,
                 _ => true,
             }
@@ -1144,7 +1169,6 @@ impl<I: Interner> Ord for RegionKind<I> {
                 (&RePlaceholder(ref __self_0), &RePlaceholder(ref __arg_1_0)) => {
                     Ord::cmp(__self_0, __arg_1_0)
                 }
-                (&ReEmpty(ref __self_0), &ReEmpty(ref __arg_1_0)) => Ord::cmp(__self_0, __arg_1_0),
                 (&ReErased, &ReErased) => Ordering::Equal,
                 _ => Ordering::Equal,
             }
@@ -1182,10 +1206,6 @@ impl<I: Interner> hash::Hash for RegionKind<I> {
                 hash::Hash::hash(&regionkind_discriminant(self), state);
                 hash::Hash::hash(__self_0, state)
             }
-            (&ReEmpty(ref __self_0),) => {
-                hash::Hash::hash(&regionkind_discriminant(self), state);
-                hash::Hash::hash(__self_0, state)
-            }
             (&ReErased,) => {
                 hash::Hash::hash(&regionkind_discriminant(self), state);
             }
@@ -1211,8 +1231,6 @@ impl<I: Interner> fmt::Debug for RegionKind<I> {
 
             RePlaceholder(placeholder) => write!(f, "RePlaceholder({:?})", placeholder),
 
-            ReEmpty(ui) => write!(f, "ReEmpty({:?})", ui),
-
             ReErased => write!(f, "ReErased"),
         }
     }
@@ -1247,9 +1265,6 @@ where
             RePlaceholder(a) => e.emit_enum_variant(disc, |e| {
                 a.encode(e);
             }),
-            ReEmpty(a) => e.emit_enum_variant(disc, |e| {
-                a.encode(e);
-            }),
             ReErased => e.emit_enum_variant(disc, |_| {}),
         }
     }
@@ -1272,8 +1287,7 @@ where
             3 => ReStatic,
             4 => ReVar(Decodable::decode(d)),
             5 => RePlaceholder(Decodable::decode(d)),
-            6 => ReEmpty(Decodable::decode(d)),
-            7 => ReErased,
+            6 => ReErased,
             _ => panic!(
                 "{}",
                 format!(
@@ -1286,7 +1300,7 @@ where
 }
 
 // This is not a derived impl because a derive would require `I: HashStable`
-impl<CTX, I: Interner> HashStable<CTX> for RegionKind<I>
+impl<CTX: HashStableContext, I: Interner> HashStable<CTX> for RegionKind<I>
 where
     I::EarlyBoundRegion: HashStable<CTX>,
     I::BoundRegion: HashStable<CTX>,
@@ -1305,9 +1319,6 @@ where
             ReErased | ReStatic => {
                 // No variant fields to hash for these ...
             }
-            ReEmpty(universe) => {
-                universe.hash_stable(hcx, hasher);
-            }
             ReLateBound(db, br) => {
                 db.hash_stable(hcx, hasher);
                 br.hash_stable(hcx, hasher);
diff --git a/compiler/rustc_typeck/src/astconv/errors.rs b/compiler/rustc_typeck/src/astconv/errors.rs
index ff39bf36129b..a9152bdc5978 100644
--- a/compiler/rustc_typeck/src/astconv/errors.rs
+++ b/compiler/rustc_typeck/src/astconv/errors.rs
@@ -29,6 +29,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         self.tcx().sess.emit_err(MissingTypeParams {
             span,
             def_span: self.tcx().def_span(def_id),
+            span_snippet: self.tcx().sess.source_map().span_to_snippet(span).ok(),
             missing_type_params,
             empty_generic_args,
         });
diff --git a/compiler/rustc_typeck/src/astconv/generics.rs b/compiler/rustc_typeck/src/astconv/generics.rs
index ad0da4bed457..afac75de2d96 100644
--- a/compiler/rustc_typeck/src/astconv/generics.rs
+++ b/compiler/rustc_typeck/src/astconv/generics.rs
@@ -647,7 +647,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 multispan.push_span_label(span_late, note);
                 tcx.struct_span_lint_hir(
                     LATE_BOUND_LIFETIME_ARGUMENTS,
-                    args.args[0].id(),
+                    args.args[0].hir_id(),
                     multispan,
                     |lint| {
                         lint.build(msg).emit();
diff --git a/compiler/rustc_typeck/src/astconv/mod.rs b/compiler/rustc_typeck/src/astconv/mod.rs
index 5c96f1c4623a..b3cbb606c728 100644
--- a/compiler/rustc_typeck/src/astconv/mod.rs
+++ b/compiler/rustc_typeck/src/astconv/mod.rs
@@ -26,7 +26,8 @@ use rustc_hir::intravisit::{walk_generics, Visitor as _};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin};
 use rustc_middle::middle::stability::AllowUnstable;
-use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, Subst, SubstsRef};
+use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
+use rustc_middle::ty::DynKind;
 use rustc_middle::ty::GenericParamDefKind;
 use rustc_middle::ty::{
     self, Const, DefIdTree, EarlyBinder, IsSuggestable, Ty, TyCtxt, TypeVisitable,
@@ -144,7 +145,7 @@ enum ConvertedBindingKind<'a, 'tcx> {
 /// instantiated with some generic arguments providing `'a` explicitly,
 /// we taint those arguments with `ExplicitLateBound::Yes` so that we
 /// can provide an appropriate diagnostic later.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, Debug)]
 pub enum ExplicitLateBound {
     Yes,
     No,
@@ -167,7 +168,7 @@ pub(crate) enum GenericArgPosition {
 
 /// A marker denoting that the generic arguments that were
 /// provided did not match the respective generic parameters.
-#[derive(Clone, Default)]
+#[derive(Clone, Default, Debug)]
 pub struct GenericArgCountMismatch {
     /// Indicates whether a fatal error was reported (`Some`), or just a lint (`None`).
     pub reported: Option<ErrorGuaranteed>,
@@ -177,7 +178,7 @@ pub struct GenericArgCountMismatch {
 
 /// Decorates the result of a generic argument count mismatch
 /// check with whether explicit late bounds were provided.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct GenericArgCountResult {
     pub explicit_late_bound: ExplicitLateBound,
     pub correct: Result<(), GenericArgCountMismatch>,
@@ -201,7 +202,7 @@ pub trait CreateSubstsForGenericArgsCtxt<'a, 'tcx> {
 }
 
 impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     pub fn ast_region_to_region(
         &self,
         lifetime: &hir::Lifetime,
@@ -210,7 +211,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let tcx = self.tcx();
         let lifetime_name = |def_id| tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id));
 
-        let r = match tcx.named_region(lifetime.hir_id) {
+        match tcx.named_region(lifetime.hir_id) {
             Some(rl::Region::Static) => tcx.lifetimes.re_static,
 
             Some(rl::Region::LateBound(debruijn, index, def_id)) => {
@@ -255,9 +256,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     tcx.lifetimes.re_static
                 })
             }
-        };
-        debug!("ast_region_to_region(lifetime={:?}) yields {:?}", lifetime, r);
-        r
+        }
     }
 
     /// Given a path `path` that refers to an item `I` with the declared generics `decl_generics`,
@@ -317,7 +316,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     /// `[Vec<u8>, u8]` and `generic_args` are the arguments for the associated
     /// type itself: `['a]`. The returned `SubstsRef` concatenates these two
     /// lists: `[Vec<u8>, u8, 'a]`.
-    #[tracing::instrument(level = "debug", skip(self, span))]
+    #[instrument(level = "debug", skip(self, span), ret)]
     fn create_substs_for_ast_path<'a>(
         &self,
         span: Span,
@@ -366,7 +365,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         // here and so associated type bindings will be handled regardless of whether there are any
         // non-`Self` generic parameters.
         if generics.params.is_empty() {
-            return (tcx.intern_substs(&[]), arg_count);
+            return (tcx.intern_substs(parent_substs), arg_count);
         }
 
         struct SubstsForAstPathCtxt<'a, 'tcx> {
@@ -399,7 +398,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     if has_default {
                         tcx.check_optional_stability(
                             param.def_id,
-                            Some(arg.id()),
+                            Some(arg.hir_id()),
                             arg.span(),
                             None,
                             AllowUnstable::No,
@@ -537,11 +536,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             &mut substs_ctx,
         );
 
-        debug!(
-            "create_substs_for_ast_path(generic_params={:?}, self_ty={:?}) -> {:?}",
-            generics, self_ty, substs
-        );
-
         (substs, arg_count)
     }
 
@@ -592,7 +586,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
     pub(crate) fn create_substs_for_associated_item(
         &self,
-        tcx: TyCtxt<'tcx>,
         span: Span,
         item_def_id: DefId,
         item_segment: &hir::PathSegment<'_>,
@@ -602,22 +595,16 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             "create_substs_for_associated_item(span: {:?}, item_def_id: {:?}, item_segment: {:?}",
             span, item_def_id, item_segment
         );
-        if tcx.generics_of(item_def_id).params.is_empty() {
-            self.prohibit_generics(slice::from_ref(item_segment).iter(), |_| {});
-
-            parent_substs
-        } else {
-            self.create_substs_for_ast_path(
-                span,
-                item_def_id,
-                parent_substs,
-                item_segment,
-                item_segment.args(),
-                item_segment.infer_args,
-                None,
-            )
-            .0
-        }
+        self.create_substs_for_ast_path(
+            span,
+            item_def_id,
+            parent_substs,
+            item_segment,
+            item_segment.args(),
+            item_segment.infer_args,
+            None,
+        )
+        .0
     }
 
     /// Instantiates the path for the given trait reference, assuming that it's
@@ -716,7 +703,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     /// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be
     /// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly,
     /// however.
-    #[tracing::instrument(level = "debug", skip(self, span, constness, bounds, speculative))]
+    #[instrument(level = "debug", skip(self, span, constness, bounds, speculative))]
     pub(crate) fn instantiate_poly_trait_ref(
         &self,
         trait_ref: &hir::TraitRef<'_>,
@@ -808,7 +795,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         ty::TraitRef::new(trait_def_id, substs)
     }
 
-    #[tracing::instrument(level = "debug", skip(self, span))]
+    #[instrument(level = "debug", skip(self, span))]
     fn create_substs_for_ast_trait_ref<'a>(
         &self,
         span: Span,
@@ -922,7 +909,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     /// **A note on binders:** there is an implied binder around
     /// `param_ty` and `ast_bounds`. See `instantiate_poly_trait_ref`
     /// for more details.
-    #[tracing::instrument(level = "debug", skip(self, ast_bounds, bounds))]
+    #[instrument(level = "debug", skip(self, ast_bounds, bounds))]
     pub(crate) fn add_bounds<'hir, I: Iterator<Item = &'hir hir::GenericBound<'hir>>>(
         &self,
         param_ty: Ty<'tcx>,
@@ -1028,10 +1015,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     /// **A note on binders:** given something like `T: for<'a> Iterator<Item = &'a u32>`, the
     /// `trait_ref` here will be `for<'a> T: Iterator`. The `binding` data however is from *inside*
     /// the binder (e.g., `&'a u32`) and hence may reference bound regions.
-    #[tracing::instrument(
-        level = "debug",
-        skip(self, bounds, speculative, dup_bindings, path_span)
-    )]
+    #[instrument(level = "debug", skip(self, bounds, speculative, dup_bindings, path_span))]
     fn add_predicates_for_ast_type_binding(
         &self,
         hir_ref_id: hir::HirId,
@@ -1123,14 +1107,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             let ident = Ident::new(assoc_item.name, binding.item_name.span);
             let item_segment = hir::PathSegment {
                 ident,
-                hir_id: Some(binding.hir_id),
-                res: None,
+                hir_id: binding.hir_id,
+                res: Res::Err,
                 args: Some(binding.gen_args),
                 infer_args: false,
             };
 
             let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item(
-                tcx,
                 path_span,
                 assoc_item.def_id,
                 &item_segment,
@@ -1193,11 +1176,11 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 // `<T as Iterator>::Item = u32`
                 let assoc_item_def_id = projection_ty.skip_binder().item_def_id;
                 let def_kind = tcx.def_kind(assoc_item_def_id);
-                match (def_kind, term) {
-                    (hir::def::DefKind::AssocTy, ty::Term::Ty(_))
-                    | (hir::def::DefKind::AssocConst, ty::Term::Const(_)) => (),
+                match (def_kind, term.unpack()) {
+                    (hir::def::DefKind::AssocTy, ty::TermKind::Ty(_))
+                    | (hir::def::DefKind::AssocConst, ty::TermKind::Const(_)) => (),
                     (_, _) => {
-                        let got = if let ty::Term::Ty(_) = term { "type" } else { "constant" };
+                        let got = if let Some(_) = term.ty() { "type" } else { "constant" };
                         let expected = def_kind.descr(assoc_item_def_id);
                         tcx.sess
                             .struct_span_err(
@@ -1262,6 +1245,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         trait_bounds: &[hir::PolyTraitRef<'_>],
         lifetime: &hir::Lifetime,
         borrowed: bool,
+        representation: DynKind,
     ) -> Ty<'tcx> {
         let tcx = self.tcx();
 
@@ -1385,9 +1369,11 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         let pred = bound_predicate.rebind(pred);
                         // A `Self` within the original bound will be substituted with a
                         // `trait_object_dummy_self`, so check for that.
-                        let references_self = match pred.skip_binder().term {
-                            ty::Term::Ty(ty) => ty.walk().any(|arg| arg == dummy_self.into()),
-                            ty::Term::Const(c) => c.ty().walk().any(|arg| arg == dummy_self.into()),
+                        let references_self = match pred.skip_binder().term.unpack() {
+                            ty::TermKind::Ty(ty) => ty.walk().any(|arg| arg == dummy_self.into()),
+                            ty::TermKind::Const(c) => {
+                                c.ty().walk().any(|arg| arg == dummy_self.into())
+                            }
                         };
 
                         // If the projection output contains `Self`, force the user to
@@ -1580,7 +1566,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         };
         debug!("region_bound: {:?}", region_bound);
 
-        let ty = tcx.mk_dynamic(existential_predicates, region_bound);
+        let ty = tcx.mk_dynamic(existential_predicates, region_bound, representation);
         debug!("trait_object_type: {:?}", ty);
         ty
     }
@@ -1855,7 +1841,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                     [.., hir::PathSegment {
                                         ident,
                                         args,
-                                        res: Some(Res::Def(DefKind::Enum, _)),
+                                        res: Res::Def(DefKind::Enum, _),
                                         ..
                                     }, _] => (
                                         // We need to include the `::` in `Type::Variant::<Args>`
@@ -2106,7 +2092,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             self.ast_path_to_mono_trait_ref(span, trait_def_id, self_ty, trait_segment, false);
 
         let item_substs = self.create_substs_for_associated_item(
-            tcx,
             span,
             item_def_id,
             item_segment,
@@ -2137,24 +2122,22 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             let types_and_spans: Vec<_> = segments
                 .clone()
                 .flat_map(|segment| {
-                    segment.res.and_then(|res| {
-                        if segment.args().args.is_empty() {
-                            None
-                        } else {
-                            Some((
-                            match res {
-                                Res::PrimTy(ty) => format!("{} `{}`", res.descr(), ty.name()),
+                    if segment.args().args.is_empty() {
+                        None
+                    } else {
+                        Some((
+                            match segment.res {
+                                Res::PrimTy(ty) => format!("{} `{}`", segment.res.descr(), ty.name()),
                                 Res::Def(_, def_id)
                                 if let Some(name) = self.tcx().opt_item_name(def_id) => {
-                                    format!("{} `{name}`", res.descr())
+                                    format!("{} `{name}`", segment.res.descr())
                                 }
                                 Res::Err => "this type".to_string(),
-                                _ => res.descr().to_string(),
+                                _ => segment.res.descr().to_string(),
                             },
                             segment.ident.span,
                         ))
-                        }
-                    })
+                    }
                 })
                 .collect();
             let this_type = match &types_and_spans[..] {
@@ -2370,7 +2353,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
         let span = path.span;
         match path.res {
-            Res::Def(DefKind::OpaqueTy, did) => {
+            Res::Def(DefKind::OpaqueTy | DefKind::ImplTraitPlaceholder, did) => {
                 // Check for desugared `impl Trait`.
                 assert!(ty::is_impl_trait_defn(tcx, did).is_none());
                 let item_segment = path.segments.split_last().unwrap();
@@ -2599,7 +2582,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
     /// Turns a `hir::Ty` into a `Ty`. For diagnostics' purposes we keep track of whether trait
     /// objects are borrowed like `&dyn Trait` to avoid emitting redundant errors.
-    #[tracing::instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     fn ast_ty_to_ty_inner(&self, ast_ty: &hir::Ty<'_>, borrowed: bool, in_path: bool) -> Ty<'tcx> {
         let tcx = self.tcx();
 
@@ -2628,22 +2611,26 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     Some(ast_ty),
                 ))
             }
-            hir::TyKind::TraitObject(bounds, ref lifetime, _) => {
+            hir::TyKind::TraitObject(bounds, ref lifetime, repr) => {
                 self.maybe_lint_bare_trait(ast_ty, in_path);
-                self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed)
+                let repr = match repr {
+                    TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
+                    TraitObjectSyntax::DynStar => ty::DynStar,
+                };
+                self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed, repr)
             }
             hir::TyKind::Path(hir::QPath::Resolved(ref maybe_qself, ref path)) => {
                 debug!(?maybe_qself, ?path);
                 let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself));
                 self.res_to_ty(opt_self_ty, path, false)
             }
-            hir::TyKind::OpaqueDef(item_id, lifetimes) => {
+            hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => {
                 let opaque_ty = tcx.hir().item(item_id);
                 let def_id = item_id.def_id.to_def_id();
 
                 match opaque_ty.kind {
                     hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
-                        self.impl_trait_ty_to_ty(def_id, lifetimes, origin)
+                        self.impl_trait_ty_to_ty(def_id, lifetimes, origin, in_trait)
                     }
                     ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i),
                 }
@@ -2682,7 +2669,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 self.normalize_ty(ast_ty.span, array_ty)
             }
             hir::TyKind::Typeof(ref e) => {
-                let ty = tcx.type_of(tcx.hir().local_def_id(e.hir_id));
+                let ty_erased = tcx.type_of(tcx.hir().local_def_id(e.hir_id));
+                let ty = tcx.fold_regions(ty_erased, |r, _| {
+                    if r.is_erased() { tcx.lifetimes.re_static } else { r }
+                });
                 let span = ast_ty.span;
                 tcx.sess.emit_err(TypeofReservedKeywordUsed {
                     span,
@@ -2703,17 +2693,17 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             hir::TyKind::Err => tcx.ty_error(),
         };
 
-        debug!(?result_ty);
-
         self.record_ty(ast_ty.hir_id, result_ty, ast_ty.span);
         result_ty
     }
 
+    #[instrument(level = "debug", skip(self), ret)]
     fn impl_trait_ty_to_ty(
         &self,
         def_id: DefId,
         lifetimes: &[hir::GenericArg<'_>],
         origin: OpaqueTyOrigin,
+        in_trait: bool,
     ) -> Ty<'tcx> {
         debug!("impl_trait_ty_to_ty(def_id={:?}, lifetimes={:?})", def_id, lifetimes);
         let tcx = self.tcx();
@@ -2757,9 +2747,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         });
         debug!("impl_trait_ty_to_ty: substs={:?}", substs);
 
-        let ty = tcx.mk_opaque(def_id, substs);
-        debug!("impl_trait_ty_to_ty: {}", ty);
-        ty
+        if in_trait { tcx.mk_projection(def_id, substs) } else { tcx.mk_opaque(def_id, substs) }
     }
 
     pub fn ty_of_arg(&self, ty: &hir::Ty<'_>, expected_ty: Option<Ty<'tcx>>) -> Ty<'tcx> {
@@ -2953,8 +2941,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 // though we can easily give a hint that ought to be
                 // relevant.
                 err.note(
-                    "lifetimes appearing in an associated type are not considered constrained",
+                    "lifetimes appearing in an associated or opaque type are not considered constrained",
                 );
+                err.note("consider introducing a named lifetime parameter");
             }
 
             err.emit();
@@ -3005,7 +2994,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     /// Make sure that we are in the condition to suggest the blanket implementation.
     fn maybe_lint_blanket_trait_impl(&self, self_ty: &hir::Ty<'_>, diag: &mut Diagnostic) {
         let tcx = self.tcx();
-        let parent_id = tcx.hir().get_parent_item(self_ty.hir_id);
+        let parent_id = tcx.hir().get_parent_item(self_ty.hir_id).def_id;
         if let hir::Node::Item(hir::Item {
             kind:
                 hir::ItemKind::Impl(hir::Impl {
diff --git a/compiler/rustc_typeck/src/check/_match.rs b/compiler/rustc_typeck/src/check/_match.rs
index 2d50412007d9..201927091a60 100644
--- a/compiler/rustc_typeck/src/check/_match.rs
+++ b/compiler/rustc_typeck/src/check/_match.rs
@@ -12,7 +12,7 @@ use rustc_trait_selection::traits::{
 };
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "debug", ret)]
     pub fn check_match(
         &self,
         expr: &'tcx hir::Expr<'tcx>,
@@ -137,9 +137,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Some(&arm.body),
                 arm_ty,
                 Some(&mut |err| {
-                    let Some(ret) = self.ret_type_span else {
-                        return;
-                    };
+                    let Some(ret) = self
+                        .tcx
+                        .hir()
+                        .find_by_def_id(self.body_id.owner.def_id)
+                        .and_then(|owner| owner.fn_decl())
+                        .map(|decl| decl.output.span())
+                    else { return; };
                     let Expectation::IsLast(stmt) = orig_expected else {
                         return
                     };
@@ -212,9 +216,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // We won't diverge unless the scrutinee or all arms diverge.
         self.diverges.set(scrut_diverges | all_arms_diverge);
 
-        let match_ty = coercion.complete(self);
-        debug!(?match_ty);
-        match_ty
+        coercion.complete(self)
     }
 
     /// When the previously checked expression (the scrutinee) diverges,
@@ -470,58 +472,77 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    // When we have a `match` as a tail expression in a `fn` with a returned `impl Trait`
-    // we check if the different arms would work with boxed trait objects instead and
-    // provide a structured suggestion in that case.
+    /// When we have a `match` as a tail expression in a `fn` with a returned `impl Trait`
+    /// we check if the different arms would work with boxed trait objects instead and
+    /// provide a structured suggestion in that case.
     pub(crate) fn opt_suggest_box_span(
         &self,
         first_ty: Ty<'tcx>,
         second_ty: Ty<'tcx>,
         orig_expected: Expectation<'tcx>,
     ) -> Option<Span> {
+        // FIXME(compiler-errors): This really shouldn't need to be done during the
+        // "good" path of typeck, but here we are.
         match orig_expected {
-            Expectation::ExpectHasType(expected)
-                if self.in_tail_expr
-                    && self.return_type_has_opaque
-                    && self.can_coerce(first_ty, expected)
-                    && self.can_coerce(second_ty, expected) =>
-            {
-                let obligations = self.fulfillment_cx.borrow().pending_obligations();
-                let mut suggest_box = !obligations.is_empty();
-                'outer: for o in obligations {
-                    for outer_ty in &[first_ty, second_ty] {
-                        match o.predicate.kind().skip_binder() {
-                            ty::PredicateKind::Trait(t) => {
-                                let pred = ty::Binder::dummy(ty::PredicateKind::Trait(
-                                    ty::TraitPredicate {
-                                        trait_ref: ty::TraitRef {
-                                            def_id: t.def_id(),
-                                            substs: self.tcx.mk_substs_trait(*outer_ty, &[]),
-                                        },
-                                        constness: t.constness,
-                                        polarity: t.polarity,
-                                    },
-                                ));
-                                let obl = Obligation::new(
-                                    o.cause.clone(),
-                                    self.param_env,
-                                    pred.to_predicate(self.tcx),
-                                );
-                                suggest_box &= self.predicate_must_hold_modulo_regions(&obl);
-                                if !suggest_box {
-                                    // We've encountered some obligation that didn't hold, so the
-                                    // return expression can't just be boxed. We don't need to
-                                    // evaluate the rest of the obligations.
-                                    break 'outer;
-                                }
+            Expectation::ExpectHasType(expected) => {
+                let TypeVariableOrigin {
+                    span,
+                    kind: TypeVariableOriginKind::OpaqueTypeInference(rpit_def_id),
+                    ..
+                } = self.type_var_origin(expected)? else { return None; };
+
+                let sig = *self
+                    .typeck_results
+                    .borrow()
+                    .liberated_fn_sigs()
+                    .get(hir::HirId::make_owner(self.body_id.owner.def_id))?;
+
+                let substs = sig.output().walk().find_map(|arg| {
+                    if let ty::GenericArgKind::Type(ty) = arg.unpack()
+                        && let ty::Opaque(def_id, substs) = *ty.kind()
+                        && def_id == rpit_def_id
+                    {
+                        Some(substs)
+                    } else {
+                        None
+                    }
+                })?;
+                let opaque_ty = self.tcx.mk_opaque(rpit_def_id, substs);
+
+                if !self.can_coerce(first_ty, expected) || !self.can_coerce(second_ty, expected) {
+                    return None;
+                }
+
+                for ty in [first_ty, second_ty] {
+                    for pred in self.tcx.bound_explicit_item_bounds(rpit_def_id).transpose_iter() {
+                        let pred = pred.map_bound(|(pred, _)| *pred).subst(self.tcx, substs);
+                        let pred = match pred.kind().skip_binder() {
+                            ty::PredicateKind::Trait(mut trait_pred) => {
+                                assert_eq!(trait_pred.trait_ref.self_ty(), opaque_ty);
+                                trait_pred.trait_ref.substs =
+                                    self.tcx.mk_substs_trait(ty, &trait_pred.trait_ref.substs[1..]);
+                                pred.kind().rebind(trait_pred).to_predicate(self.tcx)
                             }
-                            _ => {}
+                            ty::PredicateKind::Projection(mut proj_pred) => {
+                                assert_eq!(proj_pred.projection_ty.self_ty(), opaque_ty);
+                                proj_pred.projection_ty.substs = self
+                                    .tcx
+                                    .mk_substs_trait(ty, &proj_pred.projection_ty.substs[1..]);
+                                pred.kind().rebind(proj_pred).to_predicate(self.tcx)
+                            }
+                            _ => continue,
+                        };
+                        if !self.predicate_must_hold_modulo_regions(&Obligation::new(
+                            ObligationCause::misc(span, self.body_id),
+                            self.param_env,
+                            pred,
+                        )) {
+                            return None;
                         }
                     }
                 }
-                // If all the obligations hold (or there are no obligations) the tail expression
-                // we can suggest to return a boxed trait object instead of an opaque type.
-                if suggest_box { self.ret_type_span } else { None }
+
+                Some(span)
             }
             _ => None,
         }
diff --git a/compiler/rustc_typeck/src/check/callee.rs b/compiler/rustc_typeck/src/check/callee.rs
index 75f5aced8557..c82a31e65cf1 100644
--- a/compiler/rustc_typeck/src/check/callee.rs
+++ b/compiler/rustc_typeck/src/check/callee.rs
@@ -1,5 +1,5 @@
 use super::method::MethodCallee;
-use super::{Expectation, FnCtxt, TupleArgumentsFlag};
+use super::{DefIdOrName, Expectation, FnCtxt, TupleArgumentsFlag};
 use crate::type_error_struct;
 
 use rustc_errors::{struct_span_err, Applicability, Diagnostic};
@@ -17,14 +17,15 @@ use rustc_infer::{
 use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability,
 };
-use rustc_middle::ty::subst::{Subst, SubstsRef};
+use rustc_middle::ty::SubstsRef;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
 use rustc_target::spec::abi;
 use rustc_trait_selection::autoderef::Autoderef;
-use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
+use rustc_trait_selection::infer::InferCtxtExt as _;
+use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 
 use std::iter;
 
@@ -471,7 +472,25 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 };
 
                 if !self.maybe_suggest_bad_array_definition(&mut err, call_expr, callee_expr) {
-                    err.span_label(call_expr.span, "call expression requires function");
+                    if let Some((maybe_def, output_ty, _)) = self.extract_callable_info(callee_expr, callee_ty)
+                        && !self.type_is_sized_modulo_regions(self.param_env, output_ty, callee_expr.span)
+                    {
+                        let descr = match maybe_def {
+                            DefIdOrName::DefId(def_id) => self.tcx.def_kind(def_id).descr(def_id),
+                            DefIdOrName::Name(name) => name,
+                        };
+                        err.span_label(
+                            callee_expr.span,
+                            format!("this {descr} returns an unsized value `{output_ty}`, so it cannot be called")
+                        );
+                        if let DefIdOrName::DefId(def_id) = maybe_def
+                            && let Some(def_span) = self.tcx.hir().span_if_local(def_id)
+                        {
+                            err.span_label(def_span, "the callable type is defined here");
+                        }
+                    } else {
+                        err.span_label(call_expr.span, "call expression requires function");
+                    }
                 }
 
                 if let Some(span) = self.tcx.hir().res_span(def) {
diff --git a/compiler/rustc_typeck/src/check/cast.rs b/compiler/rustc_typeck/src/check/cast.rs
index 6c7b2a2889fa..81a979865acc 100644
--- a/compiler/rustc_typeck/src/check/cast.rs
+++ b/compiler/rustc_typeck/src/check/cast.rs
@@ -35,28 +35,30 @@ use crate::type_error_struct;
 use hir::def_id::LOCAL_CRATE;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
 use rustc_hir as hir;
-use rustc_hir::lang_items::LangItem;
+use rustc_infer::traits::{Obligation, ObligationCause, ObligationCauseCode};
 use rustc_middle::mir::Mutability;
 use rustc_middle::ty::adjustment::AllowTwoPhase;
 use rustc_middle::ty::cast::{CastKind, CastTy};
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{self, Ty, TypeAndMut, TypeVisitable, VariantDef};
+use rustc_middle::ty::{self, Binder, Ty, TypeAndMut, TypeVisitable, VariantDef};
 use rustc_session::lint;
 use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_trait_selection::infer::InferCtxtExt;
-use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::error_reporting::report_object_safety_error;
 
 /// Reifies a cast check to be checked once we have full type information for
 /// a function context.
 #[derive(Debug)]
 pub struct CastCheck<'tcx> {
+    /// The expression whose value is being casted
     expr: &'tcx hir::Expr<'tcx>,
+    /// The source type for the cast expression
     expr_ty: Ty<'tcx>,
     expr_span: Span,
+    /// The target type. That is, the type we are casting to.
     cast_ty: Ty<'tcx>,
     cast_span: Span,
     span: Span,
@@ -97,13 +99,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return Err(reported);
         }
 
-        if self.type_is_known_to_be_sized_modulo_regions(t, span) {
+        if self.type_is_sized_modulo_regions(self.param_env, t, span) {
             return Ok(Some(PointerKind::Thin));
         }
 
         Ok(match *t.kind() {
             ty::Slice(_) | ty::Str => Some(PointerKind::Length),
-            ty::Dynamic(ref tty, ..) => Some(PointerKind::VTable(tty.principal_def_id())),
+            ty::Dynamic(ref tty, _, ty::Dyn) => Some(PointerKind::VTable(tty.principal_def_id())),
             ty::Adt(def, substs) if def.is_struct() => match def.non_enum_variant().fields.last() {
                 None => Some(PointerKind::Thin),
                 Some(f) => {
@@ -140,6 +142,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             | ty::Generator(..)
             | ty::Adt(..)
             | ty::Never
+            | ty::Dynamic(_, _, ty::DynStar)
             | ty::Error(_) => {
                 let reported = self
                     .tcx
@@ -201,8 +204,76 @@ fn make_invalid_casting_error<'a, 'tcx>(
     )
 }
 
+pub enum CastCheckResult<'tcx> {
+    Ok,
+    Deferred(CastCheck<'tcx>),
+    Err(ErrorGuaranteed),
+}
+
+pub fn check_cast<'tcx>(
+    fcx: &FnCtxt<'_, 'tcx>,
+    expr: &'tcx hir::Expr<'tcx>,
+    expr_ty: Ty<'tcx>,
+    cast_ty: Ty<'tcx>,
+    cast_span: Span,
+    span: Span,
+) -> CastCheckResult<'tcx> {
+    if cast_ty.is_dyn_star() {
+        check_dyn_star_cast(fcx, expr, expr_ty, cast_ty)
+    } else {
+        match CastCheck::new(fcx, expr, expr_ty, cast_ty, cast_span, span) {
+            Ok(check) => CastCheckResult::Deferred(check),
+            Err(e) => CastCheckResult::Err(e),
+        }
+    }
+}
+
+fn check_dyn_star_cast<'tcx>(
+    fcx: &FnCtxt<'_, 'tcx>,
+    expr: &'tcx hir::Expr<'tcx>,
+    expr_ty: Ty<'tcx>,
+    cast_ty: Ty<'tcx>,
+) -> CastCheckResult<'tcx> {
+    // Find the bounds in the dyn*. For eaxmple, if we have
+    //
+    //    let x = 22_usize as dyn* (Clone + Debug + 'static)
+    //
+    // this would return `existential_predicates = [?Self: Clone, ?Self: Debug]` and `region = 'static`.
+    let (existential_predicates, region) = match cast_ty.kind() {
+        ty::Dynamic(predicates, region, ty::DynStar) => (predicates, region),
+        _ => panic!("Invalid dyn* cast_ty"),
+    };
+
+    let cause = ObligationCause::new(
+        expr.span,
+        fcx.body_id,
+        // FIXME(dyn-star): Use a better obligation cause code
+        ObligationCauseCode::MiscObligation,
+    );
+
+    // For each existential predicate (e.g., `?Self: Clone`) substitute
+    // the type of the expression (e.g., `usize` in our example above)
+    // and then require that the resulting predicate (e.g., `usize: Clone`)
+    // holds (it does).
+    for existential_predicate in existential_predicates.iter() {
+        let predicate = existential_predicate.with_self_ty(fcx.tcx, expr_ty);
+        fcx.register_predicate(Obligation::new(cause.clone(), fcx.param_env, predicate));
+    }
+
+    // Enforce the region bound `'static` (e.g., `usize: 'static`, in our example).
+    fcx.register_predicate(Obligation::new(
+        cause,
+        fcx.param_env,
+        fcx.tcx.mk_predicate(Binder::dummy(ty::PredicateKind::TypeOutlives(
+            ty::OutlivesPredicate(expr_ty, *region),
+        ))),
+    ));
+
+    CastCheckResult::Ok
+}
+
 impl<'a, 'tcx> CastCheck<'tcx> {
-    pub fn new(
+    fn new(
         fcx: &FnCtxt<'a, 'tcx>,
         expr: &'tcx hir::Expr<'tcx>,
         expr_ty: Ty<'tcx>,
@@ -217,7 +288,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
         // cases now. We do a more thorough check at the end, once
         // inference is more completely known.
         match cast_ty.kind() {
-            ty::Dynamic(..) | ty::Slice(..) => {
+            ty::Dynamic(_, _, ty::Dyn) | ty::Slice(..) => {
                 let reported = check.report_cast_to_unsized_type(fcx);
                 Err(reported)
             }
@@ -705,7 +776,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
 
         debug!("check_cast({}, {:?} as {:?})", self.expr.hir_id, self.expr_ty, self.cast_ty);
 
-        if !fcx.type_is_known_to_be_sized_modulo_regions(self.cast_ty, self.span)
+        if !fcx.type_is_sized_modulo_regions(fcx.param_env, self.cast_ty, self.span)
             && !self.cast_ty.has_infer_types()
         {
             self.report_cast_to_unsized_type(fcx);
@@ -856,6 +927,12 @@ impl<'a, 'tcx> CastCheck<'tcx> {
             (Int(Char) | Int(Bool), Int(_)) => Ok(CastKind::PrimIntCast),
 
             (Int(_) | Float, Int(_) | Float) => Ok(CastKind::NumericCast),
+
+            // FIXME(dyn-star): this needs more conditions...
+            (_, DynStar) => Ok(CastKind::DynStarCast),
+
+            // FIXME(dyn-star): do we want to allow dyn* upcasting or other casts?
+            (DynStar, _) => Err(CastError::IllegalCast),
         }
     }
 
@@ -1084,10 +1161,3 @@ impl<'a, 'tcx> CastCheck<'tcx> {
         );
     }
 }
-
-impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
-    fn type_is_known_to_be_sized_modulo_regions(&self, ty: Ty<'tcx>, span: Span) -> bool {
-        let lang_item = self.tcx.require_lang_item(LangItem::Sized, None);
-        traits::type_known_to_meet_bound_modulo_regions(self, self.param_env, ty, lang_item, span)
-    }
-}
diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs
index 5cdb2acd9f3c..d82ee8f48c52 100644
--- a/compiler/rustc_typeck/src/check/check.rs
+++ b/compiler/rustc_typeck/src/check/check.rs
@@ -101,12 +101,11 @@ pub(super) fn check_fn<'a, 'tcx>(
             decl.output.span(),
             param_env,
         ));
-    // If we replaced declared_ret_ty with infer vars, then we must be infering
+    // If we replaced declared_ret_ty with infer vars, then we must be inferring
     // an opaque type, so set a flag so we can improve diagnostics.
     fcx.return_type_has_opaque = ret_ty != declared_ret_ty;
 
     fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty)));
-    fcx.ret_type_span = Some(decl.output.span());
 
     let span = body.value.span;
 
@@ -610,12 +609,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes<'tcx>(
         fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) {
             match arg.kind {
                 hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments {
-                    [
-                        PathSegment {
-                            res: Some(Res::SelfTy { trait_: _, alias_to: impl_ref }),
-                            ..
-                        },
-                    ] => {
+                    [PathSegment { res: Res::SelfTy { trait_: _, alias_to: impl_ref }, .. }] => {
                         let impl_ty_name =
                             impl_ref.map(|(def_id, _)| self.tcx.def_path_str(def_id));
                         self.selftys.push((path.span, impl_ty_name));
@@ -788,19 +782,19 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
     let _indenter = indenter();
     match tcx.def_kind(id.def_id) {
         DefKind::Static(..) => {
-            tcx.ensure().typeck(id.def_id);
-            maybe_check_static_with_link_section(tcx, id.def_id);
-            check_static_inhabited(tcx, id.def_id);
+            tcx.ensure().typeck(id.def_id.def_id);
+            maybe_check_static_with_link_section(tcx, id.def_id.def_id);
+            check_static_inhabited(tcx, id.def_id.def_id);
         }
         DefKind::Const => {
-            tcx.ensure().typeck(id.def_id);
+            tcx.ensure().typeck(id.def_id.def_id);
         }
         DefKind::Enum => {
             let item = tcx.hir().item(id);
             let hir::ItemKind::Enum(ref enum_definition, _) = item.kind else {
                 return;
             };
-            check_enum(tcx, &enum_definition.variants, item.def_id);
+            check_enum(tcx, &enum_definition.variants, item.def_id.def_id);
         }
         DefKind::Fn => {} // entirely within check_item_body
         DefKind::Impl => {
@@ -813,7 +807,7 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
                 check_impl_items_against_trait(
                     tcx,
                     it.span,
-                    it.def_id,
+                    it.def_id.def_id,
                     impl_trait_ref,
                     &impl_.items,
                 );
@@ -851,10 +845,10 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
             }
         }
         DefKind::Struct => {
-            check_struct(tcx, id.def_id);
+            check_struct(tcx, id.def_id.def_id);
         }
         DefKind::Union => {
-            check_union(tcx, id.def_id);
+            check_union(tcx, id.def_id.def_id);
         }
         DefKind::OpaqueTy => {
             let item = tcx.hir().item(id);
@@ -867,7 +861,7 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
             // See https://github.com/rust-lang/rust/issues/75100
             if !tcx.sess.opts.actually_rustdoc {
                 let substs = InternalSubsts::identity_for_item(tcx, item.def_id.to_def_id());
-                check_opaque(tcx, item.def_id, substs, &origin);
+                check_opaque(tcx, item.def_id.def_id, substs, &origin);
             }
         }
         DefKind::TyAlias => {
@@ -894,7 +888,7 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
                 }
             } else {
                 for item in items {
-                    let def_id = item.id.def_id;
+                    let def_id = item.id.def_id.def_id;
                     let generics = tcx.generics_of(def_id);
                     let own_counts = generics.own_counts();
                     if generics.params.len() - own_counts.lifetimes != 0 {
@@ -1464,7 +1458,7 @@ fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: L
     def.destructor(tcx); // force the destructor to be evaluated
 
     if vs.is_empty() {
-        if let Some(attr) = tcx.get_attr(def_id.to_def_id(), sym::repr) {
+        if let Some(attr) = tcx.get_attrs(def_id.to_def_id(), sym::repr).next() {
             struct_span_err!(
                 tcx.sess,
                 attr.span,
@@ -1543,7 +1537,7 @@ fn detect_discriminant_duplicate<'tcx>(
             None => {
                 // At this point we know this discriminant is a duplicate, and was not explicitly
                 // assigned by the user. Here we iterate backwards to fetch the HIR for the last
-                // explictly assigned discriminant, and letting the user know that this was the
+                // explicitly assigned discriminant, and letting the user know that this was the
                 // increment startpoint, and how many steps from there leading to the duplicate
                 if let Some((n, hir::Variant { span, ident, .. })) =
                     vs[..idx].iter().rev().enumerate().find(|v| v.1.disr_expr.is_some())
@@ -1566,7 +1560,7 @@ fn detect_discriminant_duplicate<'tcx>(
     };
 
     // Here we loop through the discriminants, comparing each discriminant to another.
-    // When a duplicate is detected, we instatiate an error and point to both
+    // When a duplicate is detected, we instantiate an error and point to both
     // initial and duplicate value. The duplicate discriminant is then discarded by swapping
     // it with the last element and decrementing the `vec.len` (which is why we have to evaluate
     // `discrs.len()` anew every iteration, and why this could be tricky to do in a functional
diff --git a/compiler/rustc_typeck/src/check/closure.rs b/compiler/rustc_typeck/src/check/closure.rs
index fee872155f5b..84ea06a460bb 100644
--- a/compiler/rustc_typeck/src/check/closure.rs
+++ b/compiler/rustc_typeck/src/check/closure.rs
@@ -3,7 +3,7 @@
 use super::{check_fn, Expectation, FnCtxt, GeneratorTypes};
 
 use crate::astconv::AstConv;
-use crate::rustc_middle::ty::subst::Subst;
+use hir::def::DefKind;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
@@ -29,7 +29,12 @@ struct ExpectedSig<'tcx> {
 }
 
 struct ClosureSignatures<'tcx> {
+    /// The signature users of the closure see.
     bound_sig: ty::PolyFnSig<'tcx>,
+    /// The signature within the function body.
+    /// This mostly differs in the sense that lifetimes are now early bound and any
+    /// opaque types from the signature expectation are overriden in case there are
+    /// explicit hidden types written by the user in the closure signature.
     liberated_sig: ty::FnSig<'tcx>,
 }
 
@@ -58,7 +63,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.check_closure(expr, expected_kind, decl, body, gen, expected_sig)
     }
 
-    #[instrument(skip(self, expr, body, decl), level = "debug")]
+    #[instrument(skip(self, expr, body, decl), level = "debug", ret)]
     fn check_closure(
         &self,
         expr: &hir::Expr<'_>,
@@ -158,11 +163,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             },
         );
 
-        let closure_type = self.tcx.mk_closure(expr_def_id.to_def_id(), closure_substs.substs);
-
-        debug!(?expr.hir_id, ?closure_type);
-
-        closure_type
+        self.tcx.mk_closure(expr_def_id.to_def_id(), closure_substs.substs)
     }
 
     /// Given the expected type, figures out what it can about this closure we
@@ -262,7 +263,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// The `cause_span` should be the span that caused us to
     /// have this expected signature, or `None` if we can't readily
     /// know that.
-    #[instrument(level = "debug", skip(self, cause_span))]
+    #[instrument(level = "debug", skip(self, cause_span), ret)]
     fn deduce_sig_from_projection(
         &self,
         cause_span: Option<Span>,
@@ -317,7 +318,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             hir::Unsafety::Normal,
             Abi::Rust,
         ));
-        debug!(?sig);
 
         Some(ExpectedSig { cause_span, sig })
     }
@@ -448,18 +448,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Along the way, it also writes out entries for types that the user
         // wrote into our typeck results, which are then later used by the privacy
         // check.
-        match self.check_supplied_sig_against_expectation(
+        match self.merge_supplied_sig_with_expectation(
             hir_id,
             expr_def_id,
             decl,
             body,
-            &closure_sigs,
+            closure_sigs,
         ) {
             Ok(infer_ok) => self.register_infer_ok_obligations(infer_ok),
-            Err(_) => return self.sig_of_closure_no_expectation(hir_id, expr_def_id, decl, body),
+            Err(_) => self.sig_of_closure_no_expectation(hir_id, expr_def_id, decl, body),
         }
-
-        closure_sigs
     }
 
     fn sig_of_closure_with_mismatched_number_of_arguments(
@@ -501,21 +499,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Enforce the user's types against the expectation. See
     /// `sig_of_closure_with_expectation` for details on the overall
     /// strategy.
-    fn check_supplied_sig_against_expectation(
+    #[instrument(level = "debug", skip(self, hir_id, expr_def_id, decl, body, expected_sigs))]
+    fn merge_supplied_sig_with_expectation(
         &self,
         hir_id: hir::HirId,
         expr_def_id: DefId,
         decl: &hir::FnDecl<'_>,
         body: &hir::Body<'_>,
-        expected_sigs: &ClosureSignatures<'tcx>,
-    ) -> InferResult<'tcx, ()> {
+        mut expected_sigs: ClosureSignatures<'tcx>,
+    ) -> InferResult<'tcx, ClosureSignatures<'tcx>> {
         // Get the signature S that the user gave.
         //
         // (See comment on `sig_of_closure_with_expectation` for the
         // meaning of these letters.)
         let supplied_sig = self.supplied_sig_of_closure(hir_id, expr_def_id, decl, body);
 
-        debug!("check_supplied_sig_against_expectation: supplied_sig={:?}", supplied_sig);
+        debug!(?supplied_sig);
 
         // FIXME(#45727): As discussed in [this comment][c1], naively
         // forcing equality here actually results in suboptimal error
@@ -533,23 +532,27 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // [c2]: https://github.com/rust-lang/rust/pull/45072#issuecomment-341096796
         self.commit_if_ok(|_| {
             let mut all_obligations = vec![];
+            let inputs: Vec<_> = iter::zip(
+                decl.inputs,
+                supplied_sig.inputs().skip_binder(), // binder moved to (*) below
+            )
+            .map(|(hir_ty, &supplied_ty)| {
+                // Instantiate (this part of..) S to S', i.e., with fresh variables.
+                self.replace_bound_vars_with_fresh_vars(
+                    hir_ty.span,
+                    LateBoundRegionConversionTime::FnCall,
+                    // (*) binder moved to here
+                    supplied_sig.inputs().rebind(supplied_ty),
+                )
+            })
+            .collect();
 
             // The liberated version of this signature should be a subtype
             // of the liberated form of the expectation.
             for ((hir_ty, &supplied_ty), expected_ty) in iter::zip(
-                iter::zip(
-                    decl.inputs,
-                    supplied_sig.inputs().skip_binder(), // binder moved to (*) below
-                ),
+                iter::zip(decl.inputs, &inputs),
                 expected_sigs.liberated_sig.inputs(), // `liberated_sig` is E'.
             ) {
-                // Instantiate (this part of..) S to S', i.e., with fresh variables.
-                let supplied_ty = self.replace_bound_vars_with_fresh_vars(
-                    hir_ty.span,
-                    LateBoundRegionConversionTime::FnCall,
-                    supplied_sig.inputs().rebind(supplied_ty),
-                ); // recreated from (*) above
-
                 // Check that E' = S'.
                 let cause = self.misc(hir_ty.span);
                 let InferOk { value: (), obligations } =
@@ -568,7 +571,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .eq(expected_sigs.liberated_sig.output(), supplied_output_ty)?;
             all_obligations.extend(obligations);
 
-            Ok(InferOk { value: (), obligations: all_obligations })
+            let inputs = inputs.into_iter().map(|ty| self.resolve_vars_if_possible(ty));
+
+            expected_sigs.liberated_sig = self.tcx.mk_fn_sig(
+                inputs,
+                supplied_output_ty,
+                expected_sigs.liberated_sig.c_variadic,
+                hir::Unsafety::Normal,
+                Abi::RustCall,
+            );
+
+            Ok(InferOk { value: expected_sigs, obligations: all_obligations })
         })
     }
 
@@ -576,7 +589,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// types that the user gave into a signature.
     ///
     /// Also, record this closure signature for later.
-    #[instrument(skip(self, decl, body), level = "debug")]
+    #[instrument(skip(self, decl, body), level = "debug", ret)]
     fn supplied_sig_of_closure(
         &self,
         hir_id: hir::HirId,
@@ -628,8 +641,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ),
             bound_vars,
         );
-
-        debug!(?result);
+        // Astconv can't normalize inputs or outputs with escaping bound vars,
+        // so normalize them here, after we've wrapped them in a binder.
+        let result = self.normalize_associated_types_in(self.tcx.hir().span(hir_id), result);
 
         let c_result = self.inh.infcx.canonicalize_response(result);
         self.typeck_results.borrow_mut().user_provided_sigs.insert(expr_def_id, c_result);
@@ -643,7 +657,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// user specified. The "desugared" return type is an `impl
     /// Future<Output = T>`, so we do this by searching through the
     /// obligations to extract the `T`.
-    #[instrument(skip(self), level = "debug")]
+    #[instrument(skip(self), level = "debug", ret)]
     fn deduce_future_output_from_obligations(
         &self,
         expr_def_id: DefId,
@@ -687,9 +701,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .map(|e| e.map_bound(|e| *e).transpose_tuple2())
                 .find_map(|(p, s)| get_future_output(p.subst(self.tcx, substs), s.0))?,
             ty::Error(_) => return None,
+            ty::Projection(proj)
+                if self.tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder =>
+            {
+                self.tcx
+                    .bound_explicit_item_bounds(proj.item_def_id)
+                    .transpose_iter()
+                    .map(|e| e.map_bound(|e| *e).transpose_tuple2())
+                    .find_map(|(p, s)| get_future_output(p.subst(self.tcx, proj.substs), s.0))?
+            }
             _ => span_bug!(
                 self.tcx.def_span(expr_def_id),
-                "async fn generator return type not an inference variable"
+                "async fn generator return type not an inference variable: {ret_ty}"
             ),
         };
 
@@ -704,7 +727,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             );
         self.register_predicates(obligations);
 
-        debug!("deduce_future_output_from_obligations: output_ty={:?}", output_ty);
         Some(output_ty)
     }
 
diff --git a/compiler/rustc_typeck/src/check/coercion.rs b/compiler/rustc_typeck/src/check/coercion.rs
index def592c46c2e..d738e5632561 100644
--- a/compiler/rustc_typeck/src/check/coercion.rs
+++ b/compiler/rustc_typeck/src/check/coercion.rs
@@ -1683,7 +1683,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                     expected,
                     found,
                     can_suggest,
-                    fcx.tcx.hir().local_def_id_to_hir_id(fcx.tcx.hir().get_parent_item(id)),
+                    fcx.tcx.hir().get_parent_item(id).into(),
                 );
             }
             if !pointing_at_return_type {
@@ -1692,7 +1692,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         }
 
         let parent_id = fcx.tcx.hir().get_parent_item(id);
-        let parent_item = fcx.tcx.hir().get_by_def_id(parent_id);
+        let parent_item = fcx.tcx.hir().get_by_def_id(parent_id.def_id);
 
         if let (Some(expr), Some(_), Some((fn_decl, _, _))) =
             (expression, blk_id, fcx.get_node_fn_decl(parent_item))
@@ -1704,7 +1704,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                 expected,
                 found,
                 id,
-                fcx.tcx.hir().local_def_id_to_hir_id(parent_id),
+                parent_id.into(),
             );
         }
 
diff --git a/compiler/rustc_typeck/src/check/compare_method.rs b/compiler/rustc_typeck/src/check/compare_method.rs
index 804306814a24..ae98a8f6209d 100644
--- a/compiler/rustc_typeck/src/check/compare_method.rs
+++ b/compiler/rustc_typeck/src/check/compare_method.rs
@@ -1,18 +1,22 @@
 use super::potentially_plural_count;
 use crate::errors::LifetimesOrBoundsMismatchOnTrait;
-use rustc_data_structures::fx::FxHashSet;
+use hir::def_id::DefId;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit;
 use rustc_hir::{GenericParamKind, ImplItemKind, TraitItemKind};
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
+use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{self, TyCtxtInferExt};
 use rustc_infer::traits::util;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
 use rustc_middle::ty::util::ExplicitSelf;
-use rustc_middle::ty::{self, DefIdTree};
+use rustc_middle::ty::InternalSubsts;
+use rustc_middle::ty::{
+    self, AssocItem, DefIdTree, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable,
+};
 use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt};
 use rustc_span::Span;
 use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
@@ -136,11 +140,12 @@ pub(crate) fn compare_impl_method<'tcx>(
 ///
 /// Finally we register each of these predicates as an obligation and check that
 /// they hold.
+#[instrument(level = "debug", skip(tcx, impl_m_span, impl_trait_ref))]
 fn compare_predicate_entailment<'tcx>(
     tcx: TyCtxt<'tcx>,
-    impl_m: &ty::AssocItem,
+    impl_m: &AssocItem,
     impl_m_span: Span,
-    trait_m: &ty::AssocItem,
+    trait_m: &AssocItem,
     impl_trait_ref: ty::TraitRef<'tcx>,
 ) -> Result<(), ErrorGuaranteed> {
     let trait_to_impl_substs = impl_trait_ref.substs;
@@ -266,6 +271,7 @@ fn compare_predicate_entailment<'tcx>(
 
         let trait_sig = tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs);
         let trait_sig = tcx.liberate_late_bound_regions(impl_m.def_id, trait_sig);
+
         // Next, add all inputs and output as well-formed tys. Importantly,
         // we have to do this before normalization, since the normalized ty may
         // not contain the input parameters. See issue #87748.
@@ -284,12 +290,26 @@ fn compare_predicate_entailment<'tcx>(
         // type would be more appropriate. In other places we have a `Vec<Span>`
         // corresponding to their `Vec<Predicate>`, but we don't have that here.
         // Fixing this would improve the output of test `issue-83765.rs`.
-        let sub_result = infcx
+        let mut result = infcx
             .at(&cause, param_env)
             .sup(trait_fty, impl_fty)
             .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok));
 
-        if let Err(terr) = sub_result {
+        // HACK(RPITIT): #101614. When we are trying to infer the hidden types for
+        // RPITITs, we need to equate the output tys instead of just subtyping. If
+        // we just use `sup` above, we'll end up `&'static str <: _#1t`, which causes
+        // us to infer `_#1t = #'_#2r str`, where `'_#2r` is unconstrained, which gets
+        // fixed up to `ReEmpty`, and which is certainly not what we want.
+        if trait_fty.has_infer_types() {
+            result = result.and_then(|()| {
+                infcx
+                    .at(&cause, param_env)
+                    .eq(trait_sig.output(), impl_sig.output())
+                    .map(|infer_ok| ocx.register_infer_ok_obligations(infer_ok))
+            });
+        }
+
+        if let Err(terr) = result {
             debug!("sub_types failed: impl ty {:?}, trait ty {:?}", impl_fty, trait_fty);
 
             let (impl_err_span, trait_err_span) =
@@ -415,6 +435,227 @@ fn compare_predicate_entailment<'tcx>(
     })
 }
 
+pub fn collect_trait_impl_trait_tys<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    def_id: DefId,
+) -> Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed> {
+    let impl_m = tcx.opt_associated_item(def_id).unwrap();
+    let trait_m = tcx.opt_associated_item(impl_m.trait_item_def_id.unwrap()).unwrap();
+    let impl_trait_ref = tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap();
+    let param_env = tcx.param_env(def_id);
+
+    let trait_to_impl_substs = impl_trait_ref.substs;
+
+    let impl_m_hir_id = tcx.hir().local_def_id_to_hir_id(impl_m.def_id.expect_local());
+    let return_span = tcx.hir().fn_decl_by_hir_id(impl_m_hir_id).unwrap().output.span();
+    let cause = ObligationCause::new(
+        return_span,
+        impl_m_hir_id,
+        ObligationCauseCode::CompareImplItemObligation {
+            impl_item_def_id: impl_m.def_id.expect_local(),
+            trait_item_def_id: trait_m.def_id,
+            kind: impl_m.kind,
+        },
+    );
+
+    // Create mapping from impl to placeholder.
+    let impl_to_placeholder_substs = InternalSubsts::identity_for_item(tcx, impl_m.def_id);
+
+    // Create mapping from trait to placeholder.
+    let trait_to_placeholder_substs =
+        impl_to_placeholder_substs.rebase_onto(tcx, impl_m.container_id(tcx), trait_to_impl_substs);
+
+    tcx.infer_ctxt().enter(|ref infcx| {
+        let ocx = ObligationCtxt::new(infcx);
+
+        let norm_cause = ObligationCause::misc(return_span, impl_m_hir_id);
+        let impl_return_ty = ocx.normalize(
+            norm_cause.clone(),
+            param_env,
+            infcx
+                .replace_bound_vars_with_fresh_vars(
+                    return_span,
+                    infer::HigherRankedType,
+                    tcx.fn_sig(impl_m.def_id),
+                )
+                .output(),
+        );
+
+        let mut collector =
+            ImplTraitInTraitCollector::new(&ocx, return_span, param_env, impl_m_hir_id);
+        let unnormalized_trait_return_ty = tcx
+            .liberate_late_bound_regions(
+                impl_m.def_id,
+                tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs),
+            )
+            .output()
+            .fold_with(&mut collector);
+        let trait_return_ty =
+            ocx.normalize(norm_cause.clone(), param_env, unnormalized_trait_return_ty);
+
+        let wf_tys = FxHashSet::from_iter([unnormalized_trait_return_ty, trait_return_ty]);
+
+        match infcx.at(&cause, param_env).eq(trait_return_ty, impl_return_ty) {
+            Ok(infer::InferOk { value: (), obligations }) => {
+                ocx.register_obligations(obligations);
+            }
+            Err(terr) => {
+                let mut diag = struct_span_err!(
+                    tcx.sess,
+                    cause.span(),
+                    E0053,
+                    "method `{}` has an incompatible return type for trait",
+                    trait_m.name
+                );
+                let hir = tcx.hir();
+                infcx.note_type_err(
+                    &mut diag,
+                    &cause,
+                    hir.get_if_local(impl_m.def_id)
+                        .and_then(|node| node.fn_decl())
+                        .map(|decl| (decl.output.span(), "return type in trait".to_owned())),
+                    Some(infer::ValuePairs::Terms(ExpectedFound {
+                        expected: trait_return_ty.into(),
+                        found: impl_return_ty.into(),
+                    })),
+                    terr,
+                    false,
+                    false,
+                );
+                return Err(diag.emit());
+            }
+        }
+
+        // Check that all obligations are satisfied by the implementation's
+        // RPITs.
+        let errors = ocx.select_all_or_error();
+        if !errors.is_empty() {
+            let reported = infcx.report_fulfillment_errors(&errors, None, false);
+            return Err(reported);
+        }
+
+        // Finally, resolve all regions. This catches wily misuses of
+        // lifetime parameters.
+        let outlives_environment = OutlivesEnvironment::with_bounds(
+            param_env,
+            Some(infcx),
+            infcx.implied_bounds_tys(param_env, impl_m_hir_id, wf_tys),
+        );
+        infcx.check_region_obligations_and_report_errors(
+            impl_m.def_id.expect_local(),
+            &outlives_environment,
+        );
+
+        let mut collected_tys = FxHashMap::default();
+        for (def_id, (ty, substs)) in collector.types {
+            match infcx.fully_resolve(ty) {
+                Ok(ty) => {
+                    // `ty` contains free regions that we created earlier while liberating the
+                    // trait fn signature.  However, projection normalization expects `ty` to
+                    // contains `def_id`'s early-bound regions.
+                    let id_substs = InternalSubsts::identity_for_item(tcx, def_id);
+                    debug!(?id_substs, ?substs);
+                    let map: FxHashMap<ty::GenericArg<'tcx>, ty::GenericArg<'tcx>> = substs
+                        .iter()
+                        .enumerate()
+                        .map(|(index, arg)| (arg, id_substs[index]))
+                        .collect();
+                    debug!(?map);
+
+                    let ty = tcx.fold_regions(ty, |region, _| {
+                        if let ty::ReFree(_) = region.kind() {
+                            map[&region.into()].expect_region()
+                        } else {
+                            region
+                        }
+                    });
+                    debug!(%ty);
+                    collected_tys.insert(def_id, ty);
+                }
+                Err(err) => {
+                    tcx.sess.delay_span_bug(
+                        return_span,
+                        format!("could not fully resolve: {ty} => {err:?}"),
+                    );
+                    collected_tys.insert(def_id, tcx.ty_error());
+                }
+            }
+        }
+
+        Ok(&*tcx.arena.alloc(collected_tys))
+    })
+}
+
+struct ImplTraitInTraitCollector<'a, 'tcx> {
+    ocx: &'a ObligationCtxt<'a, 'tcx>,
+    types: FxHashMap<DefId, (Ty<'tcx>, ty::SubstsRef<'tcx>)>,
+    span: Span,
+    param_env: ty::ParamEnv<'tcx>,
+    body_id: hir::HirId,
+}
+
+impl<'a, 'tcx> ImplTraitInTraitCollector<'a, 'tcx> {
+    fn new(
+        ocx: &'a ObligationCtxt<'a, 'tcx>,
+        span: Span,
+        param_env: ty::ParamEnv<'tcx>,
+        body_id: hir::HirId,
+    ) -> Self {
+        ImplTraitInTraitCollector { ocx, types: FxHashMap::default(), span, param_env, body_id }
+    }
+}
+
+impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> {
+    fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
+        self.ocx.infcx.tcx
+    }
+
+    fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
+        if let ty::Projection(proj) = ty.kind()
+            && self.tcx().def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
+        {
+            if let Some((ty, _)) = self.types.get(&proj.item_def_id) {
+                return *ty;
+            }
+            //FIXME(RPITIT): Deny nested RPITIT in substs too
+            if proj.substs.has_escaping_bound_vars() {
+                bug!("FIXME(RPITIT): error here");
+            }
+            // Replace with infer var
+            let infer_ty = self.ocx.infcx.next_ty_var(TypeVariableOrigin {
+                span: self.span,
+                kind: TypeVariableOriginKind::MiscVariable,
+            });
+            self.types.insert(proj.item_def_id, (infer_ty, proj.substs));
+            // Recurse into bounds
+            for pred in self.tcx().bound_explicit_item_bounds(proj.item_def_id).transpose_iter() {
+                let pred_span = pred.0.1;
+
+                let pred = pred.map_bound(|(pred, _)| *pred).subst(self.tcx(), proj.substs);
+                let pred = pred.fold_with(self);
+                let pred = self.ocx.normalize(
+                    ObligationCause::misc(self.span, self.body_id),
+                    self.param_env,
+                    pred,
+                );
+
+                self.ocx.register_obligation(traits::Obligation::new(
+                    ObligationCause::new(
+                        self.span,
+                        self.body_id,
+                        ObligationCauseCode::BindingObligation(proj.item_def_id, pred_span),
+                    ),
+                    self.param_env,
+                    pred,
+                ));
+            }
+            infer_ty
+        } else {
+            ty.super_fold_with(self)
+        }
+    }
+}
+
 fn check_region_bounds_on_impl_item<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_m: &ty::AssocItem,
@@ -1308,7 +1549,7 @@ fn compare_type_predicate_entailment<'tcx>(
 /// For default associated types the normalization is not possible (the value
 /// from the impl could be overridden). We also can't normalize generic
 /// associated types (yet) because they contain bound parameters.
-#[tracing::instrument(level = "debug", skip(tcx))]
+#[instrument(level = "debug", skip(tcx))]
 pub fn check_type_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
     trait_ty: &ty::AssocItem,
diff --git a/compiler/rustc_typeck/src/check/demand.rs b/compiler/rustc_typeck/src/check/demand.rs
index 07046f3f0326..264df8b914b0 100644
--- a/compiler/rustc_typeck/src/check/demand.rs
+++ b/compiler/rustc_typeck/src/check/demand.rs
@@ -42,6 +42,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.suggest_boxing_when_appropriate(err, expr, expected, expr_ty);
         self.suggest_missing_parentheses(err, expr);
         self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected);
+        self.suggest_copied_or_cloned(err, expr, expr_ty, expected);
         self.note_type_is_not_clone(err, expected, expr_ty, expr);
         self.note_need_for_fn_pointer(err, expected, expr_ty);
         self.note_internal_mutation_in_method(err, expr, expected, expr_ty);
@@ -130,7 +131,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ///
     /// N.B., this code relies on `self.diverges` to be accurate. In particular, assignments to `!`
     /// will be permitted if the diverges flag is currently "always".
-    #[tracing::instrument(level = "debug", skip(self, expr, expected_ty_expr, allow_two_phase))]
+    #[instrument(level = "debug", skip(self, expr, expected_ty_expr, allow_two_phase))]
     pub fn demand_coerce_diag(
         &self,
         expr: &hir::Expr<'tcx>,
@@ -374,7 +375,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                     let field_is_local = sole_field.did.is_local();
                     let field_is_accessible =
-                        sole_field.vis.is_accessible_from(expr.hir_id.owner.to_def_id(), self.tcx)
+                        sole_field.vis.is_accessible_from(expr.hir_id.owner.def_id, self.tcx)
                         // Skip suggestions for unstable public fields (for example `Pin::pointer`)
                         && matches!(self.tcx.eval_stability(sole_field.did, None, expr.span, None), EvalResult::Allow | EvalResult::Unmarked);
 
@@ -416,6 +417,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     hir::def::CtorKind::Const => unreachable!(),
                 };
 
+                // Suggest constructor as deep into the block tree as possible.
+                // This fixes https://github.com/rust-lang/rust/issues/101065,
+                // and also just helps make the most minimal suggestions.
+                let mut expr = expr;
+                while let hir::ExprKind::Block(block, _) = &expr.kind
+                    && let Some(expr_) = &block.expr
+                {
+                    expr = expr_
+                }
+
                 vec![
                     (expr.span.shrink_to_lo(), format!("{prefix}{variant}{open}")),
                     (expr.span.shrink_to_hi(), close.to_owned()),
@@ -589,7 +600,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let closure_params_len = closure_fn_decl.inputs.len();
         let (
             Some(Node::Expr(hir::Expr {
-                kind: hir::ExprKind::MethodCall(method_path, method_expr, _),
+                kind: hir::ExprKind::MethodCall(method_path, receiver, ..),
                 ..
             })),
             1,
@@ -597,7 +608,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return None;
         };
 
-        let self_ty = self.typeck_results.borrow().expr_ty(&method_expr[0]);
+        let self_ty = self.typeck_results.borrow().expr_ty(receiver);
         let name = method_path.ident.name;
         let is_as_ref_able = match self_ty.peel_refs().kind() {
             ty::Adt(def, _) => {
@@ -766,22 +777,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 };
                 if self.can_coerce(ref_ty, expected) {
                     let mut sugg_sp = sp;
-                    if let hir::ExprKind::MethodCall(ref segment, ref args, _) = expr.kind {
+                    if let hir::ExprKind::MethodCall(ref segment, receiver, args, _) = expr.kind {
                         let clone_trait =
                             self.tcx.require_lang_item(LangItem::Clone, Some(segment.ident.span));
-                        if let ([arg], Some(true), sym::clone) = (
-                            &args[..],
-                            self.typeck_results.borrow().type_dependent_def_id(expr.hir_id).map(
+                        if args.is_empty()
+                            && self.typeck_results.borrow().type_dependent_def_id(expr.hir_id).map(
                                 |did| {
                                     let ai = self.tcx.associated_item(did);
                                     ai.trait_container(self.tcx) == Some(clone_trait)
                                 },
-                            ),
-                            segment.ident.name,
-                        ) {
+                            ) == Some(true)
+                            && segment.ident.name == sym::clone
+                        {
                             // If this expression had a clone call when suggesting borrowing
                             // we want to suggest removing it because it'd now be unnecessary.
-                            sugg_sp = arg.span;
+                            sugg_sp = receiver.span;
                         }
                     }
                     if let Ok(src) = sm.span_to_snippet(sugg_sp) {
diff --git a/compiler/rustc_typeck/src/check/dropck.rs b/compiler/rustc_typeck/src/check/dropck.rs
index 321064ec0fc9..ab143c059820 100644
--- a/compiler/rustc_typeck/src/check/dropck.rs
+++ b/compiler/rustc_typeck/src/check/dropck.rs
@@ -144,6 +144,8 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
     let assumptions_in_impl_context = generic_assumptions.instantiate(tcx, &self_to_impl_substs);
     let assumptions_in_impl_context = assumptions_in_impl_context.predicates;
 
+    debug!(?assumptions_in_impl_context, ?dtor_predicates.predicates);
+
     let self_param_env = tcx.param_env(self_type_did);
 
     // An earlier version of this code attempted to do this checking
diff --git a/compiler/rustc_typeck/src/check/expr.rs b/compiler/rustc_typeck/src/check/expr.rs
index f6596950c2a0..48a4f40780bf 100644
--- a/compiler/rustc_typeck/src/check/expr.rs
+++ b/compiler/rustc_typeck/src/check/expr.rs
@@ -3,18 +3,15 @@
 //! See `mod.rs` for more context on type checking in general.
 
 use crate::astconv::AstConv as _;
-use crate::check::cast;
+use crate::check::cast::{self, CastCheckResult};
 use crate::check::coercion::CoerceMany;
 use crate::check::fatally_break_rust;
 use crate::check::method::SelfSource;
-use crate::check::report_unexpected_variant_res;
-use crate::check::BreakableCtxt;
-use crate::check::Diverges;
-use crate::check::DynamicCoerceMany;
 use crate::check::Expectation::{self, ExpectCastableToType, ExpectHasType, NoExpectation};
-use crate::check::FnCtxt;
-use crate::check::Needs;
-use crate::check::TupleArgumentsFlag::DontTupleArguments;
+use crate::check::{
+    report_unexpected_variant_res, BreakableCtxt, Diverges, DynamicCoerceMany, FnCtxt, Needs,
+    TupleArgumentsFlag::DontTupleArguments,
+};
 use crate::errors::{
     FieldMultiplySpecifiedInInitializer, FunctionalRecordUpdateOnNonStruct,
     YieldExprOutsideOfGenerator,
@@ -324,8 +321,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             ExprKind::Block(body, _) => self.check_block_with_expected(&body, expected),
             ExprKind::Call(callee, args) => self.check_call(expr, &callee, args, expected),
-            ExprKind::MethodCall(segment, args, _) => {
-                self.check_method_call(expr, segment, args, expected)
+            ExprKind::MethodCall(segment, receiver, args, _) => {
+                self.check_method_call(expr, segment, receiver, args, expected)
             }
             ExprKind::Cast(e, t) => self.check_expr_cast(e, t, expr),
             ExprKind::Type(e, t) => {
@@ -560,17 +557,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // We just want to check sizedness, so instead of introducing
                     // placeholder lifetimes with probing, we just replace higher lifetimes
                     // with fresh vars.
-                    let arg_span = args.get(i).map(|a| a.span);
-                    let span = arg_span.unwrap_or(expr.span);
+                    let span = args.get(i).map(|a| a.span).unwrap_or(expr.span);
                     let input = self.replace_bound_vars_with_fresh_vars(
                         span,
                         infer::LateBoundRegionConversionTime::FnCall,
                         fn_sig.input(i),
                     );
-                    self.require_type_is_sized(
-                        self.normalize_associated_types_in(span, input),
+                    self.require_type_is_sized_deferred(
+                        input,
                         span,
-                        traits::SizedArgumentType(arg_span),
+                        traits::SizedArgumentType(None),
                     );
                 }
             }
@@ -585,11 +581,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 infer::LateBoundRegionConversionTime::FnCall,
                 fn_sig.output(),
             );
-            self.require_type_is_sized(
-                self.normalize_associated_types_in(expr.span, output),
-                expr.span,
-                traits::SizedReturnType,
-            );
+            self.require_type_is_sized_deferred(output, expr.span, traits::SizedReturnType);
         }
 
         // We always require that the type provided as the value for
@@ -760,7 +752,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 kind: hir::ImplItemKind::Fn(..),
                 span: encl_fn_span,
                 ..
-            })) = self.tcx.hir().find_by_def_id(encl_item_id)
+            })) = self.tcx.hir().find_by_def_id(encl_item_id.def_id)
             {
                 // We are inside a function body, so reporting "return statement
                 // outside of function body" needs an explanation.
@@ -769,7 +761,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                 // If this didn't hold, we would not have to report an error in
                 // the first place.
-                assert_ne!(encl_item_id, encl_body_owner_id);
+                assert_ne!(encl_item_id.def_id, encl_body_owner_id);
 
                 let encl_body_id = self.tcx.hir().body_owned_by(encl_body_owner_id);
                 let encl_body = self.tcx.hir().body(encl_body_id);
@@ -889,7 +881,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return;
         }
 
-        // FIXME: Make this use SessionDiagnostic once error codes can be dynamically set.
+        // FIXME: Make this use Diagnostic once error codes can be dynamically set.
         let mut err = self.tcx.sess.struct_span_err_with_code(
             op_span,
             "invalid left-hand side of assignment",
@@ -1200,13 +1192,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         expr: &'tcx hir::Expr<'tcx>,
         segment: &hir::PathSegment<'_>,
+        rcvr: &'tcx hir::Expr<'tcx>,
         args: &'tcx [hir::Expr<'tcx>],
         expected: Expectation<'tcx>,
     ) -> Ty<'tcx> {
-        let rcvr = &args[0];
         let rcvr_t = self.check_expr(&rcvr);
         // no need to check for bot/err -- callee does that
-        let rcvr_t = self.structurally_resolved_type(args[0].span, rcvr_t);
+        let rcvr_t = self.structurally_resolved_type(rcvr.span, rcvr_t);
         let span = segment.ident.span;
 
         let method = match self.lookup_method(rcvr_t, segment, span, expr, rcvr, args) {
@@ -1223,9 +1215,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         span,
                         rcvr_t,
                         segment.ident,
-                        SelfSource::MethodCall(&args[0]),
+                        SelfSource::MethodCall(rcvr),
                         error,
-                        Some(args),
+                        Some((rcvr, args)),
                     ) {
                         err.emit();
                     }
@@ -1235,14 +1227,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         // Call the generic checker.
-        self.check_method_argument_types(
-            span,
-            expr,
-            method,
-            &args[1..],
-            DontTupleArguments,
-            expected,
-        )
+        self.check_method_argument_types(span, expr, method, &args, DontTupleArguments, expected)
     }
 
     fn check_expr_cast(
@@ -1264,8 +1249,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         } else {
             // Defer other checks until we're done type checking.
             let mut deferred_cast_checks = self.deferred_cast_checks.borrow_mut();
-            match cast::CastCheck::new(self, e, t_expr, t_cast, t.span, expr.span) {
-                Ok(cast_check) => {
+            match cast::check_cast(self, e, t_expr, t_cast, t.span, expr.span) {
+                CastCheckResult::Ok => t_cast,
+                CastCheckResult::Deferred(cast_check) => {
                     debug!(
                         "check_expr_cast: deferring cast from {:?} to {:?}: {:?}",
                         t_cast, t_expr, cast_check,
@@ -1273,7 +1259,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     deferred_cast_checks.push(cast_check);
                     t_cast
                 }
-                Err(_) => self.tcx.ty_error(),
+                CastCheckResult::Err(ErrorGuaranteed { .. }) => self.tcx.ty_error(),
             }
         }
     }
@@ -1317,31 +1303,30 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     fn suggest_array_len(&self, expr: &'tcx hir::Expr<'tcx>, array_len: u64) {
-        if let Some(parent_hir_id) = self.tcx.hir().find_parent_node(expr.hir_id) {
-            let ty = match self.tcx.hir().find(parent_hir_id) {
-                Some(
-                    hir::Node::Local(hir::Local { ty: Some(ty), .. })
-                    | hir::Node::Item(hir::Item { kind: hir::ItemKind::Const(ty, _), .. }),
-                ) => Some(ty),
-                _ => None,
-            };
-            if let Some(ty) = ty
-                && let hir::TyKind::Array(_, length) = ty.kind
-                && let hir::ArrayLen::Body(hir::AnonConst { hir_id, .. }) = length
-                && let Some(span) = self.tcx.hir().opt_span(hir_id)
-            {
-                match self.tcx.sess.diagnostic().steal_diagnostic(span, StashKey::UnderscoreForArrayLengths) {
-                    Some(mut err) => {
-                        err.span_suggestion(
-                            span,
-                            "consider specifying the array length",
-                            array_len,
-                            Applicability::MaybeIncorrect,
-                        );
-                        err.emit();
-                    }
-                    None => ()
+        let parent_node = self.tcx.hir().parent_iter(expr.hir_id).find(|(_, node)| {
+            !matches!(node, hir::Node::Expr(hir::Expr { kind: hir::ExprKind::AddrOf(..), .. }))
+        });
+        let Some((_,
+            hir::Node::Local(hir::Local { ty: Some(ty), .. })
+            | hir::Node::Item(hir::Item { kind: hir::ItemKind::Const(ty, _), .. }))
+        ) = parent_node else {
+            return
+        };
+        if let hir::TyKind::Array(_, length) = ty.peel_refs().kind
+            && let hir::ArrayLen::Body(hir::AnonConst { hir_id, .. }) = length
+            && let Some(span) = self.tcx.hir().opt_span(hir_id)
+        {
+            match self.tcx.sess.diagnostic().steal_diagnostic(span, StashKey::UnderscoreForArrayLengths) {
+                Some(mut err) => {
+                    err.span_suggestion(
+                        span,
+                        "consider specifying the array length",
+                        array_len,
+                        Applicability::MaybeIncorrect,
+                    );
+                    err.emit();
                 }
+                None => ()
             }
         }
     }
@@ -1741,9 +1726,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let private_fields: Vec<&ty::FieldDef> = variant
                 .fields
                 .iter()
-                .filter(|field| {
-                    !field.vis.is_accessible_from(tcx.parent_module(expr_id).to_def_id(), tcx)
-                })
+                .filter(|field| !field.vis.is_accessible_from(tcx.parent_module(expr_id), tcx))
                 .collect();
 
             if !private_fields.is_empty() {
@@ -2355,7 +2338,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if let ty::Adt(def, _) = output_ty.kind() && !def.is_enum() {
                 def.non_enum_variant().fields.iter().any(|field| {
                     field.ident(self.tcx) == ident
-                        && field.vis.is_accessible_from(expr.hir_id.owner.to_def_id(), self.tcx)
+                        && field.vis.is_accessible_from(expr.hir_id.owner.def_id, self.tcx)
                 })
             } else if let ty::Tuple(tys) = output_ty.kind()
                 && let Ok(idx) = ident.as_str().parse::<usize>()
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs b/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
index 20d25d508d22..4522678802ba 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
@@ -20,14 +20,12 @@ use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
 use rustc_infer::infer::{InferOk, InferResult};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::subst::{
-    self, GenericArgKind, InternalSubsts, Subst, SubstsRef, UserSelfTy, UserSubsts,
-};
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{
     self, AdtKind, CanonicalUserType, DefIdTree, EarlyBinder, GenericParamDefKind, ToPolyTraitRef,
     ToPredicate, Ty, UserType,
 };
+use rustc_middle::ty::{GenericArgKind, InternalSubsts, SubstsRef, UserSelfTy, UserSubsts};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
@@ -83,7 +81,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.resolve_vars_with_obligations_and_mutate_fulfillment(ty, |_| {})
     }
 
-    #[instrument(skip(self, mutate_fulfillment_errors), level = "debug")]
+    #[instrument(skip(self, mutate_fulfillment_errors), level = "debug", ret)]
     pub(in super::super) fn resolve_vars_with_obligations_and_mutate_fulfillment(
         &self,
         mut ty: Ty<'tcx>,
@@ -107,10 +105,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // indirect dependencies that don't seem worth tracking
         // precisely.
         self.select_obligations_where_possible(false, mutate_fulfillment_errors);
-        ty = self.resolve_vars_if_possible(ty);
-
-        debug!(?ty);
-        ty
+        self.resolve_vars_if_possible(ty)
     }
 
     pub(in super::super) fn record_deferred_call_resolution(
@@ -412,7 +407,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     rhs_span: opt_input_expr.map(|expr| expr.span),
                     is_lit: opt_input_expr
                         .map_or(false, |expr| matches!(expr.kind, ExprKind::Lit(_))),
-                    output_pred: None,
+                    output_ty: None,
                 },
             ),
             self.param_env,
@@ -442,6 +437,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub fn require_type_is_sized_deferred(
+        &self,
+        ty: Ty<'tcx>,
+        span: Span,
+        code: traits::ObligationCauseCode<'tcx>,
+    ) {
+        if !ty.references_error() {
+            self.deferred_sized_obligations.borrow_mut().push((ty, span, code));
+        }
+    }
+
     pub fn register_bound(
         &self,
         ty: Ty<'tcx>,
@@ -481,21 +487,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn array_length_to_const(&self, length: &hir::ArrayLen) -> ty::Const<'tcx> {
         match length {
             &hir::ArrayLen::Infer(_, span) => self.ct_infer(self.tcx.types.usize, None, span),
-            hir::ArrayLen::Body(anon_const) => self.to_const(anon_const),
+            hir::ArrayLen::Body(anon_const) => {
+                let const_def_id = self.tcx.hir().local_def_id(anon_const.hir_id);
+                let span = self.tcx.hir().span(anon_const.hir_id);
+                let c = ty::Const::from_anon_const(self.tcx, const_def_id);
+                self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
+                self.normalize_associated_types_in(span, c)
+            }
         }
     }
 
-    pub fn to_const(&self, ast_c: &hir::AnonConst) -> ty::Const<'tcx> {
-        let const_def_id = self.tcx.hir().local_def_id(ast_c.hir_id);
-        let c = ty::Const::from_anon_const(self.tcx, const_def_id);
-        self.register_wf_obligation(
-            c.into(),
-            self.tcx.hir().span(ast_c.hir_id),
-            ObligationCauseCode::WellFormed(None),
-        );
-        c
-    }
-
     pub fn const_arg_to_const(
         &self,
         ast_c: &hir::AnonConst,
@@ -554,7 +555,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Registers an obligation for checking later, during regionck, that `arg` is well-formed.
     pub fn register_wf_obligation(
         &self,
-        arg: subst::GenericArg<'tcx>,
+        arg: ty::GenericArg<'tcx>,
         span: Span,
         code: traits::ObligationCauseCode<'tcx>,
     ) {
@@ -979,7 +980,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if found != self.tcx.types.unit {
             return;
         }
-        if let ExprKind::MethodCall(path_segment, [rcvr, ..], _) = expr.kind {
+        if let ExprKind::MethodCall(path_segment, rcvr, ..) = expr.kind {
             if self
                 .typeck_results
                 .borrow()
@@ -1266,7 +1267,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 &mut self,
                 param: &ty::GenericParamDef,
                 arg: &GenericArg<'_>,
-            ) -> subst::GenericArg<'tcx> {
+            ) -> ty::GenericArg<'tcx> {
                 match (&param.kind, arg) {
                     (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => {
                         <dyn AstConv<'_>>::ast_region_to_region(self.fcx, lt, Some(param)).into()
@@ -1290,10 +1291,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
             fn inferred_kind(
                 &mut self,
-                substs: Option<&[subst::GenericArg<'tcx>]>,
+                substs: Option<&[ty::GenericArg<'tcx>]>,
                 param: &ty::GenericParamDef,
                 infer_args: bool,
-            ) -> subst::GenericArg<'tcx> {
+            ) -> ty::GenericArg<'tcx> {
                 let tcx = self.fcx.tcx();
                 match param.kind {
                     GenericParamDefKind::Lifetime => {
@@ -1405,7 +1406,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         })
     }
 
-    #[tracing::instrument(level = "debug", skip(self, code, span, def_id, substs))]
+    #[instrument(level = "debug", skip(self, code, span, substs))]
     fn add_required_obligations_with_code(
         &self,
         span: Span,
@@ -1413,15 +1414,42 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         substs: SubstsRef<'tcx>,
         code: impl Fn(usize, Span) -> ObligationCauseCode<'tcx>,
     ) {
+        let param_env = self.param_env;
+
+        let remap = match self.tcx.def_kind(def_id) {
+            // Associated consts have `Self: ~const Trait` bounds that should be satisfiable when
+            // `Self: Trait` is satisfied because it does not matter whether the impl is `const`.
+            // Therefore we have to remap the param env here to be non-const.
+            hir::def::DefKind::AssocConst => true,
+            hir::def::DefKind::AssocFn
+                if self.tcx.def_kind(self.tcx.parent(def_id)) == hir::def::DefKind::Trait =>
+            {
+                // N.B.: All callsites to this function involve checking a path expression.
+                //
+                // When instantiating a trait method as a function item, it does not actually matter whether
+                // the trait is `const` or not, or whether `where T: ~const Tr` needs to be satisfied as
+                // `const`. If we were to introduce instantiating trait methods as `const fn`s, we would
+                // check that after this, either via a bound `where F: ~const FnOnce` or when coercing to a
+                // `const fn` pointer.
+                //
+                // FIXME(fee1-dead) FIXME(const_trait_impl): update this doc when trait methods can satisfy
+                // `~const FnOnce` or can be coerced to `const fn` pointer.
+                true
+            }
+            _ => false,
+        };
         let (bounds, _) = self.instantiate_bounds(span, def_id, &substs);
 
-        for obligation in traits::predicates_for_generics(
+        for mut obligation in traits::predicates_for_generics(
             |idx, predicate_span| {
                 traits::ObligationCause::new(span, self.body_id, code(idx, predicate_span))
             },
-            self.param_env,
+            param_env,
             bounds,
         ) {
+            if remap {
+                obligation = obligation.without_const(self.tcx);
+            }
             self.register_predicate(obligation);
         }
     }
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/arg_matrix.rs b/compiler/rustc_typeck/src/check/fn_ctxt/arg_matrix.rs
index 7602f2550e85..fc83994caf53 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/arg_matrix.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/arg_matrix.rs
@@ -130,14 +130,17 @@ impl<'tcx> ArgMatrix<'tcx> {
         let ai = &self.expected_indices;
         let ii = &self.provided_indices;
 
+        // Issue: 100478, when we end the iteration,
+        // `next_unmatched_idx` will point to the index of the first unmatched
+        let mut next_unmatched_idx = 0;
         for i in 0..cmp::max(ai.len(), ii.len()) {
-            // If we eliminate the last row, any left-over inputs are considered missing
+            // If we eliminate the last row, any left-over arguments are considered missing
             if i >= mat.len() {
-                return Some(Issue::Missing(i));
+                return Some(Issue::Missing(next_unmatched_idx));
             }
-            // If we eliminate the last column, any left-over arguments are extra
+            // If we eliminate the last column, any left-over inputs are extra
             if mat[i].len() == 0 {
-                return Some(Issue::Extra(i));
+                return Some(Issue::Extra(next_unmatched_idx));
             }
 
             // Make sure we don't pass the bounds of our matrix
@@ -145,6 +148,7 @@ impl<'tcx> ArgMatrix<'tcx> {
             let is_input = i < ii.len();
             if is_arg && is_input && matches!(mat[i][i], Compatibility::Compatible) {
                 // This is a satisfied input, so move along
+                next_unmatched_idx += 1;
                 continue;
             }
 
@@ -163,7 +167,7 @@ impl<'tcx> ArgMatrix<'tcx> {
             if is_input {
                 for j in 0..ai.len() {
                     // If we find at least one argument that could satisfy this input
-                    // this argument isn't useless
+                    // this input isn't useless
                     if matches!(mat[i][j], Compatibility::Compatible) {
                         useless = false;
                         break;
@@ -232,8 +236,8 @@ impl<'tcx> ArgMatrix<'tcx> {
                             if matches!(c, Compatibility::Compatible) { Some(i) } else { None }
                         })
                         .collect();
-                if compat.len() != 1 {
-                    // this could go into multiple slots, don't bother exploring both
+                if compat.len() < 1 {
+                    // try to find a cycle even when this could go into multiple slots, see #101097
                     is_cycle = false;
                     break;
                 }
@@ -309,7 +313,8 @@ impl<'tcx> ArgMatrix<'tcx> {
         }
 
         while !self.provided_indices.is_empty() || !self.expected_indices.is_empty() {
-            match self.find_issue() {
+            let res = self.find_issue();
+            match res {
                 Some(Issue::Invalid(idx)) => {
                     let compatibility = self.compatibility_matrix[idx][idx].clone();
                     let input_idx = self.provided_indices[idx];
@@ -364,7 +369,9 @@ impl<'tcx> ArgMatrix<'tcx> {
                 None => {
                     // We didn't find any issues, so we need to push the algorithm forward
                     // First, eliminate any arguments that currently satisfy their inputs
-                    for (inp, arg) in self.eliminate_satisfied() {
+                    let eliminated = self.eliminate_satisfied();
+                    assert!(!eliminated.is_empty(), "didn't eliminated any indice in this round");
+                    for (inp, arg) in eliminated {
                         matched_inputs[arg] = Some(inp);
                     }
                 }
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
index 03bd485096a9..64e7fa1a42bf 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
@@ -31,7 +31,7 @@ use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, DefIdTree, IsSuggestable, Ty, TypeSuperVisitable, TypeVisitor};
 use rustc_session::Session;
 use rustc_span::symbol::Ident;
-use rustc_span::{self, Span};
+use rustc_span::{self, sym, Span};
 use rustc_trait_selection::traits::{self, ObligationCauseCode, SelectionContext};
 
 use std::iter;
@@ -153,7 +153,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) {
         let tcx = self.tcx;
 
-        // Conceptually, we've got some number of expected inputs, and some number of provided aguments
+        // Conceptually, we've got some number of expected inputs, and some number of provided arguments
         // and we can form a grid of whether each argument could satisfy a given input:
         //      in1 | in2 | in3 | ...
         // arg1  ?  |     |     |
@@ -224,6 +224,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let minimum_input_count = expected_input_tys.len();
         let provided_arg_count = provided_args.len();
 
+        let is_const_eval_select = matches!(fn_def_id, Some(def_id) if
+            self.tcx.def_kind(def_id) == hir::def::DefKind::Fn
+            && self.tcx.is_intrinsic(def_id)
+            && self.tcx.item_name(def_id) == sym::const_eval_select);
+
         // We introduce a helper function to demand that a given argument satisfy a given input
         // This is more complicated than just checking type equality, as arguments could be coerced
         // This version writes those types back so further type checking uses the narrowed types
@@ -259,6 +264,32 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return Compatibility::Incompatible(coerce_error);
             }
 
+            // Check that second and third argument of `const_eval_select` must be `FnDef`, and additionally that
+            // the second argument must be `const fn`. The first argument must be a tuple, but this is already expressed
+            // in the function signature (`F: FnOnce<ARG>`), so I did not bother to add another check here.
+            //
+            // This check is here because there is currently no way to express a trait bound for `FnDef` types only.
+            if is_const_eval_select && (1..=2).contains(&idx) {
+                if let ty::FnDef(def_id, _) = checked_ty.kind() {
+                    if idx == 1 && !self.tcx.is_const_fn_raw(*def_id) {
+                        self.tcx
+                            .sess
+                            .struct_span_err(provided_arg.span, "this argument must be a `const fn`")
+                            .help("consult the documentation on `const_eval_select` for more information")
+                            .emit();
+                    }
+                } else {
+                    self.tcx
+                        .sess
+                        .struct_span_err(provided_arg.span, "this argument must be a function item")
+                        .note(format!("expected a function item, found {checked_ty}"))
+                        .help(
+                            "consult the documentation on `const_eval_select` for more information",
+                        )
+                        .emit();
+                }
+            }
+
             // 3. Check if the formal type is a supertype of the checked one
             //    and register any such obligations for future type checks
             let supertype_error = self
@@ -447,7 +478,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
             hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None, false),
-            hir::ExprKind::MethodCall(path_segment, _, span) => {
+            hir::ExprKind::MethodCall(path_segment, _, _, span) => {
                 let ident_span = path_segment.ident.span;
                 let ident_span = if let Some(args) = path_segment.args {
                     ident_span.with_hi(args.span_ext.hi())
@@ -499,13 +530,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .collect();
         let callee_expr = match &call_expr.peel_blocks().kind {
             hir::ExprKind::Call(callee, _) => Some(*callee),
-            hir::ExprKind::MethodCall(_, callee, _) => {
+            hir::ExprKind::MethodCall(_, receiver, ..) => {
                 if let Some((DefKind::AssocFn, def_id)) =
                     self.typeck_results.borrow().type_dependent_def(call_expr.hir_id)
                     && let Some(assoc) = tcx.opt_associated_item(def_id)
                     && assoc.fn_has_self_parameter
                 {
-                    Some(&callee[0])
+                    Some(*receiver)
                 } else {
                     None
                 }
@@ -1056,11 +1087,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
         if let Some(suggestion_text) = suggestion_text {
             let source_map = self.sess().source_map();
-            let mut suggestion = format!(
-                "{}(",
-                source_map.span_to_snippet(full_call_span).unwrap_or_else(|_| fn_def_id
-                    .map_or("".to_string(), |fn_def_id| tcx.item_name(fn_def_id).to_string()))
-            );
+            let (mut suggestion, suggestion_span) =
+                if let Some(call_span) = full_call_span.find_ancestor_inside(error_span) {
+                    ("(".to_string(), call_span.shrink_to_hi().to(error_span.shrink_to_hi()))
+                } else {
+                    (
+                        format!(
+                            "{}(",
+                            source_map.span_to_snippet(full_call_span).unwrap_or_else(|_| {
+                                fn_def_id.map_or("".to_string(), |fn_def_id| {
+                                    tcx.item_name(fn_def_id).to_string()
+                                })
+                            })
+                        ),
+                        error_span,
+                    )
+                };
             let mut needs_comma = false;
             for (expected_idx, provided_idx) in matched_inputs.iter_enumerated() {
                 if needs_comma {
@@ -1088,7 +1130,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             suggestion += ")";
             err.span_suggestion_verbose(
-                error_span,
+                suggestion_span,
                 &suggestion_text,
                 suggestion,
                 Applicability::HasPlaceholders,
@@ -1501,7 +1543,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     fn parent_item_span(&self, id: hir::HirId) -> Option<Span> {
-        let node = self.tcx.hir().get_by_def_id(self.tcx.hir().get_parent_item(id));
+        let node = self.tcx.hir().get_by_def_id(self.tcx.hir().get_parent_item(id).def_id);
         match node {
             Node::Item(&hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. })
             | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Fn(_, body_id), .. }) => {
@@ -1517,7 +1559,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     /// Given a function block's `HirId`, returns its `FnDecl` if it exists, or `None` otherwise.
     fn get_parent_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl<'tcx>, Ident)> {
-        let parent = self.tcx.hir().get_by_def_id(self.tcx.hir().get_parent_item(blk_id));
+        let parent = self.tcx.hir().get_by_def_id(self.tcx.hir().get_parent_item(blk_id).def_id);
         self.get_node_fn_decl(parent).map(|(fn_decl, ident, _)| (fn_decl, ident))
     }
 
@@ -1763,25 +1805,26 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 param,
                                 *call_hir_id,
                                 callee.span,
+                                None,
                                 args,
                             )
                         {
                             return true;
                         }
                     }
-                    // Notably, we only point to params that are local to the
-                    // item we're checking, since those are the ones we are able
-                    // to look in the final `hir::PathSegment` for. Everything else
-                    // would require a deeper search into the `qpath` than I think
-                    // is worthwhile.
-                    if let Some(param_to_point_at) = param_to_point_at
-                        && self.point_at_path_if_possible(error, def_id, param_to_point_at, qpath)
-                    {
-                        return true;
-                    }
+                }
+                // Notably, we only point to params that are local to the
+                // item we're checking, since those are the ones we are able
+                // to look in the final `hir::PathSegment` for. Everything else
+                // would require a deeper search into the `qpath` than I think
+                // is worthwhile.
+                if let Some(param_to_point_at) = param_to_point_at
+                    && self.point_at_path_if_possible(error, def_id, param_to_point_at, qpath)
+                {
+                    return true;
                 }
             }
-            hir::ExprKind::MethodCall(segment, args, ..) => {
+            hir::ExprKind::MethodCall(segment, receiver, args, ..) => {
                 for param in [param_to_point_at, fallback_param_to_point_at, self_param_to_point_at]
                     .into_iter()
                     .flatten()
@@ -1792,6 +1835,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         param,
                         hir_id,
                         segment.ident.span,
+                        Some(receiver),
                         args,
                     ) {
                         return true;
@@ -1859,7 +1903,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         param_to_point_at: ty::GenericArg<'tcx>,
         call_hir_id: hir::HirId,
         callee_span: Span,
-        args: &[hir::Expr<'tcx>],
+        receiver: Option<&'tcx hir::Expr<'tcx>>,
+        args: &'tcx [hir::Expr<'tcx>],
     ) -> bool {
         let sig = self.tcx.fn_sig(def_id).skip_binder();
         let args_referencing_param: Vec<_> = sig
@@ -1868,9 +1913,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .enumerate()
             .filter(|(_, ty)| find_param_in_ty(**ty, param_to_point_at))
             .collect();
-
         // If there's one field that references the given generic, great!
-        if let [(idx, _)] = args_referencing_param.as_slice() && let Some(arg) = args.get(*idx) {
+        if let [(idx, _)] = args_referencing_param.as_slice()
+            && let Some(arg) = receiver
+                .map_or(args.get(*idx), |rcvr| if *idx == 0 { Some(rcvr) } else { args.get(*idx - 1) }) {
             error.obligation.cause.span = arg.span.find_ancestor_in_same_ctxt(error.obligation.cause.span).unwrap_or(arg.span);
             error.obligation.cause.map_code(|parent_code| {
                 ObligationCauseCode::FunctionArgumentObligation {
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/mod.rs b/compiler/rustc_typeck/src/check/fn_ctxt/mod.rs
index e008d50aa514..d929a3e6548f 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/mod.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/mod.rs
@@ -68,8 +68,6 @@ pub struct FnCtxt<'a, 'tcx> {
     /// any).
     pub(super) ret_coercion: Option<RefCell<DynamicCoerceMany<'tcx>>>,
 
-    pub(super) ret_type_span: Option<Span>,
-
     /// Used exclusively to reduce cost of advanced evaluation used for
     /// more helpful diagnostics.
     pub(super) in_tail_expr: bool,
@@ -142,7 +140,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             param_env,
             err_count_on_creation: inh.tcx.sess.err_count(),
             ret_coercion: None,
-            ret_type_span: None,
             in_tail_expr: false,
             ret_coercion_span: Cell::new(None),
             resume_yield_tys: None,
@@ -279,7 +276,6 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
 
         let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
             self,
-            self.tcx,
             span,
             item_def_id,
             item_segment,
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs b/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs
index 939f4612d44e..c32d13090311 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs
@@ -14,9 +14,10 @@ use rustc_hir::{
 use rustc_infer::infer::{self, TyCtxtInferExt};
 use rustc_infer::traits::{self, StatementAsExpression};
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{self, Binder, IsSuggestable, Subst, ToPredicate, Ty};
+use rustc_middle::ty::{self, Binder, IsSuggestable, ToPredicate, Ty};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
+use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
@@ -143,7 +144,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         false
     }
 
-    fn extract_callable_info(
+    /// Extracts information about a callable type for diagnostics. This is a
+    /// heuristic -- it doesn't necessarily mean that a type is always callable,
+    /// because the callable type must also be well-formed to be called.
+    pub(in super::super) fn extract_callable_info(
         &self,
         expr: &Expr<'_>,
         found: Ty<'tcx>,
@@ -178,7 +182,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         }
                     })
                 }
-                ty::Dynamic(data, _) => {
+                ty::Dynamic(data, _, ty::Dyn) => {
                     data.iter().find_map(|pred| {
                         if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
                         && Some(proj.item_def_id) == self.tcx.lang_items().fn_once_output()
@@ -925,6 +929,69 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub(crate) fn suggest_copied_or_cloned(
+        &self,
+        diag: &mut Diagnostic,
+        expr: &hir::Expr<'_>,
+        expr_ty: Ty<'tcx>,
+        expected_ty: Ty<'tcx>,
+    ) {
+        let ty::Adt(adt_def, substs) = expr_ty.kind() else { return; };
+        let ty::Adt(expected_adt_def, expected_substs) = expected_ty.kind() else { return; };
+        if adt_def != expected_adt_def {
+            return;
+        }
+
+        let mut suggest_copied_or_cloned = || {
+            let expr_inner_ty = substs.type_at(0);
+            let expected_inner_ty = expected_substs.type_at(0);
+            if let ty::Ref(_, ty, hir::Mutability::Not) = expr_inner_ty.kind()
+                && self.can_eq(self.param_env, *ty, expected_inner_ty).is_ok()
+            {
+                let def_path = self.tcx.def_path_str(adt_def.did());
+                if self.type_is_copy_modulo_regions(self.param_env, *ty, expr.span) {
+                    diag.span_suggestion_verbose(
+                        expr.span.shrink_to_hi(),
+                        format!(
+                            "use `{def_path}::copied` to copy the value inside the `{def_path}`"
+                        ),
+                        ".copied()",
+                        Applicability::MachineApplicable,
+                    );
+                } else if let Some(clone_did) = self.tcx.lang_items().clone_trait()
+                    && rustc_trait_selection::traits::type_known_to_meet_bound_modulo_regions(
+                        self,
+                        self.param_env,
+                        *ty,
+                        clone_did,
+                        expr.span
+                    )
+                {
+                    diag.span_suggestion_verbose(
+                        expr.span.shrink_to_hi(),
+                        format!(
+                            "use `{def_path}::cloned` to clone the value inside the `{def_path}`"
+                        ),
+                        ".cloned()",
+                        Applicability::MachineApplicable,
+                    );
+                }
+            }
+        };
+
+        if let Some(result_did) = self.tcx.get_diagnostic_item(sym::Result)
+            && adt_def.did() == result_did
+            // Check that the error types are equal
+            && self.can_eq(self.param_env, substs.type_at(1), expected_substs.type_at(1)).is_ok()
+        {
+            suggest_copied_or_cloned();
+        } else if let Some(option_did) = self.tcx.get_diagnostic_item(sym::Option)
+            && adt_def.did() == option_did
+        {
+            suggest_copied_or_cloned();
+        }
+    }
+
     /// Suggest wrapping the block in square brackets instead of curly braces
     /// in case the block was mistaken array syntax, e.g. `{ 1 }` -> `[ 1 ]`.
     pub(crate) fn suggest_block_to_brackets(
@@ -985,7 +1052,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         found_ty: Ty<'tcx>,
         expr: &hir::Expr<'_>,
     ) {
-        let hir::ExprKind::MethodCall(segment, &[ref callee_expr], _) = expr.kind else { return; };
+        let hir::ExprKind::MethodCall(segment, callee_expr, &[], _) = expr.kind else { return; };
         let Some(clone_trait_did) = self.tcx.lang_items().clone_trait() else { return; };
         let ty::Ref(_, pointee_ty, _) = found_ty.kind() else { return };
         let results = self.typeck_results.borrow();
@@ -1066,7 +1133,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 }
 
-enum DefIdOrName {
+pub enum DefIdOrName {
     DefId(DefId),
     Name(&'static str),
 }
diff --git a/compiler/rustc_typeck/src/check/generator_interior.rs b/compiler/rustc_typeck/src/check/generator_interior.rs
index 85a0d4e44990..254a19368bfe 100644
--- a/compiler/rustc_typeck/src/check/generator_interior.rs
+++ b/compiler/rustc_typeck/src/check/generator_interior.rs
@@ -17,7 +17,6 @@ use rustc_middle::middle::region::{self, Scope, ScopeData, YieldData};
 use rustc_middle::ty::{self, RvalueScopes, Ty, TyCtxt, TypeVisitable};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
-use tracing::debug;
 
 mod drop_ranges;
 
@@ -219,7 +218,8 @@ pub fn resolve_interior<'a, 'tcx>(
         .filter_map(|mut cause| {
             // Erase regions and canonicalize late-bound regions to deduplicate as many types as we
             // can.
-            let erased = fcx.tcx.erase_regions(cause.ty);
+            let ty = fcx.normalize_associated_types_in(cause.span, cause.ty);
+            let erased = fcx.tcx.erase_regions(ty);
             if captured_tys.insert(erased) {
                 // Replace all regions inside the generator interior with late bound regions.
                 // Note that each region slot in the types gets a new fresh late bound region,
@@ -264,7 +264,7 @@ pub fn resolve_interior<'a, 'tcx>(
     // Unify the type variable inside the generator with the new witness
     match fcx.at(&fcx.misc(body.value.span), fcx.param_env).eq(interior, witness) {
         Ok(ok) => fcx.register_infer_ok_obligations(ok),
-        _ => bug!(),
+        _ => bug!("failed to relate {interior} and {witness}"),
     }
 }
 
@@ -409,8 +409,15 @@ impl<'a, 'tcx> Visitor<'tcx> for InteriorVisitor<'a, 'tcx> {
             }) {
             self.rvalue_scopes.temporary_scope(self.region_scope_tree, expr.hir_id.local_id)
         } else {
-            debug!("parent_node: {:?}", self.fcx.tcx.hir().find_parent_node(expr.hir_id));
-            match self.fcx.tcx.hir().find_parent_node(expr.hir_id) {
+            let parent_expr = self
+                .fcx
+                .tcx
+                .hir()
+                .parent_iter(expr.hir_id)
+                .find(|(_, node)| matches!(node, hir::Node::Expr(_)))
+                .map(|(id, _)| id);
+            debug!("parent_expr: {:?}", parent_expr);
+            match parent_expr {
                 Some(parent) => Some(Scope { id: parent.local_id, data: ScopeData::Node }),
                 None => {
                     self.rvalue_scopes.temporary_scope(self.region_scope_tree, expr.hir_id.local_id)
@@ -521,7 +528,7 @@ fn check_must_not_suspend_ty<'tcx>(
             }
             has_emitted
         }
-        ty::Dynamic(binder, _) => {
+        ty::Dynamic(binder, _, _) => {
             let mut has_emitted = false;
             for predicate in binder.iter() {
                 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
diff --git a/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/cfg_build.rs b/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/cfg_build.rs
index 3e96b3ffb094..016f4056bd90 100644
--- a/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/cfg_build.rs
+++ b/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/cfg_build.rs
@@ -434,7 +434,8 @@ impl<'a, 'tcx> Visitor<'tcx> for DropRangeVisitor<'a, 'tcx> {
 
                 self.handle_uninhabited_return(expr);
             }
-            ExprKind::MethodCall(_, exprs, _) => {
+            ExprKind::MethodCall(_, receiver, exprs, _) => {
+                self.visit_expr(receiver);
                 for expr in exprs {
                     self.visit_expr(expr);
                 }
diff --git a/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/record_consumed_borrow.rs b/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/record_consumed_borrow.rs
index ded0888c33e1..e22675e9d5f4 100644
--- a/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/record_consumed_borrow.rs
+++ b/compiler/rustc_typeck/src/check/generator_interior/drop_ranges/record_consumed_borrow.rs
@@ -159,8 +159,8 @@ impl<'tcx> expr_use_visitor::Delegate<'tcx> for ExprUseDelegate<'tcx> {
         bk: rustc_middle::ty::BorrowKind,
     ) {
         debug!(
-            "borrow: place_with_id = {place_with_id:?}, diag_expr_id={diag_expr_id:?}, \
-            borrow_kind={bk:?}"
+            "borrow: place_with_id = {place_with_id:#?}, diag_expr_id={diag_expr_id:#?}, \
+            borrow_kind={bk:#?}"
         );
 
         self.borrow_place(place_with_id);
diff --git a/compiler/rustc_typeck/src/check/inherited.rs b/compiler/rustc_typeck/src/check/inherited.rs
index 1439baf54406..37c830d4e385 100644
--- a/compiler/rustc_typeck/src/check/inherited.rs
+++ b/compiler/rustc_typeck/src/check/inherited.rs
@@ -38,6 +38,12 @@ pub struct Inherited<'a, 'tcx> {
 
     pub(super) fulfillment_cx: RefCell<Box<dyn TraitEngine<'tcx>>>,
 
+    // Some additional `Sized` obligations badly affect type inference.
+    // These obligations are added in a later stage of typeck.
+    // Removing these may also cause additional complications, see #101066.
+    pub(super) deferred_sized_obligations:
+        RefCell<Vec<(Ty<'tcx>, Span, traits::ObligationCauseCode<'tcx>)>>,
+
     // When we process a call like `c()` where `c` is a closure type,
     // we may not have decided yet whether `c` is a `Fn`, `FnMut`, or
     // `FnOnce` closure. In that case, we defer full resolution of the
@@ -137,6 +143,7 @@ impl<'a, 'tcx> Inherited<'a, 'tcx> {
             infcx,
             fulfillment_cx: RefCell::new(<dyn TraitEngine<'_>>::new(tcx)),
             locals: RefCell::new(Default::default()),
+            deferred_sized_obligations: RefCell::new(Vec::new()),
             deferred_call_resolutions: RefCell::new(Default::default()),
             deferred_cast_checks: RefCell::new(Vec::new()),
             deferred_transmute_checks: RefCell::new(Vec::new()),
diff --git a/compiler/rustc_typeck/src/check/intrinsic.rs b/compiler/rustc_typeck/src/check/intrinsic.rs
index 73dd7122e269..ae484b4fedaf 100644
--- a/compiler/rustc_typeck/src/check/intrinsic.rs
+++ b/compiler/rustc_typeck/src/check/intrinsic.rs
@@ -10,7 +10,6 @@ use crate::require_same_types;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_middle::traits::{ObligationCause, ObligationCauseCode};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_target::spec::abi::Abi;
@@ -95,8 +94,7 @@ pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety {
         | sym::type_id
         | sym::likely
         | sym::unlikely
-        | sym::ptr_guaranteed_eq
-        | sym::ptr_guaranteed_ne
+        | sym::ptr_guaranteed_cmp
         | sym::minnumf32
         | sym::minnumf64
         | sym::maxnumf32
@@ -302,8 +300,8 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
                 (1, vec![param(0), param(0)], tcx.intern_tup(&[param(0), tcx.types.bool]))
             }
 
-            sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {
-                (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.bool)
+            sym::ptr_guaranteed_cmp => {
+                (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.u8)
             }
 
             sym::const_allocate => {
@@ -478,7 +476,11 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         sym::simd_scatter => (3, vec![param(0), param(1), param(2)], tcx.mk_unit()),
         sym::simd_insert => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
         sym::simd_extract => (2, vec![param(0), tcx.types.u32], param(1)),
-        sym::simd_cast | sym::simd_as => (2, vec![param(0)], param(1)),
+        sym::simd_cast
+        | sym::simd_as
+        | sym::simd_cast_ptr
+        | sym::simd_expose_addr
+        | sym::simd_from_exposed_addr => (2, vec![param(0)], param(1)),
         sym::simd_bitmask => (2, vec![param(0)], param(1)),
         sym::simd_select | sym::simd_select_bitmask => {
             (2, vec![param(0), param(1), param(1)], param(1))
diff --git a/compiler/rustc_typeck/src/check/intrinsicck.rs b/compiler/rustc_typeck/src/check/intrinsicck.rs
index 721ebba65147..d8fe63dbf084 100644
--- a/compiler/rustc_typeck/src/check/intrinsicck.rs
+++ b/compiler/rustc_typeck/src/check/intrinsicck.rs
@@ -333,10 +333,10 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
                         let mut err = lint.build(msg);
                         err.span_label(expr.span, "for this argument");
                         err.help(&format!(
-                            "use the `{suggested_modifier}` modifier to have the register formatted as `{suggested_result}`",
+                            "use `{{{idx}:{suggested_modifier}}}` to have the register formatted as `{suggested_result}`",
                         ));
                         err.help(&format!(
-                            "or use the `{default_modifier}` modifier to keep the default formatting of `{default_result}`",
+                            "or use `{{{idx}:{default_modifier}}}` to keep the default formatting of `{default_result}`",
                         ));
                         err.emit();
                     },
diff --git a/compiler/rustc_typeck/src/check/method/confirm.rs b/compiler/rustc_typeck/src/check/method/confirm.rs
index 59fd5c315ae6..30731cbd03d3 100644
--- a/compiler/rustc_typeck/src/check/method/confirm.rs
+++ b/compiler/rustc_typeck/src/check/method/confirm.rs
@@ -10,7 +10,7 @@ use rustc_middle::traits::{ObligationCauseCode, UnifyReceiverContext};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, PointerCast};
 use rustc_middle::ty::adjustment::{AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::subst::{self, Subst, SubstsRef};
+use rustc_middle::ty::subst::{self, SubstsRef};
 use rustc_middle::ty::{self, GenericParamDefKind, Ty};
 use rustc_span::Span;
 use rustc_trait_selection::traits;
diff --git a/compiler/rustc_typeck/src/check/method/mod.rs b/compiler/rustc_typeck/src/check/method/mod.rs
index de26a9e56e2d..3fe9bea2299d 100644
--- a/compiler/rustc_typeck/src/check/method/mod.rs
+++ b/compiler/rustc_typeck/src/check/method/mod.rs
@@ -18,12 +18,8 @@ use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Namespace};
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::{self, InferOk};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
-use rustc_middle::ty::{
-    self, AssocKind, DefIdTree, GenericParamDefKind, ProjectionPredicate, ProjectionTy, Term,
-    ToPredicate, Ty, TypeVisitable,
-};
+use rustc_middle::ty::{self, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TypeVisitable};
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
@@ -168,7 +164,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// * `call_expr`:             the complete method call: (`foo.bar::<T1,...Tn>(...)`)
     /// * `self_expr`:             the self expression (`foo`)
     /// * `args`:                  the expressions of the arguments (`a, b + 1, ...`)
-    #[instrument(level = "debug", skip(self, call_expr, self_expr))]
+    #[instrument(level = "debug", skip(self))]
     pub fn lookup_method(
         &self,
         self_ty: Ty<'tcx>,
@@ -178,11 +174,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self_expr: &'tcx hir::Expr<'tcx>,
         args: &'tcx [hir::Expr<'tcx>],
     ) -> Result<MethodCallee<'tcx>, MethodError<'tcx>> {
-        debug!(
-            "lookup(method_name={}, self_ty={:?}, call_expr={:?}, self_expr={:?})",
-            segment.ident, self_ty, call_expr, self_expr
-        );
-
         let pick =
             self.lookup_probe(span, segment.ident, self_ty, call_expr, ProbeScope::TraitsInScope)?;
 
@@ -342,22 +333,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Construct an obligation
         let poly_trait_ref = ty::Binder::dummy(trait_ref);
-        let opt_output_ty =
-            expected.only_has_type(self).and_then(|ty| (!ty.needs_infer()).then(|| ty));
-        let opt_output_assoc_item = self.tcx.associated_items(trait_def_id).find_by_name_and_kind(
-            self.tcx,
-            Ident::from_str("Output"),
-            AssocKind::Type,
-            trait_def_id,
-        );
-        let output_pred =
-            opt_output_ty.zip(opt_output_assoc_item).map(|(output_ty, output_assoc_item)| {
-                ty::Binder::dummy(ty::PredicateKind::Projection(ProjectionPredicate {
-                    projection_ty: ProjectionTy { substs, item_def_id: output_assoc_item.def_id },
-                    term: Term::Ty(output_ty),
-                }))
-                .to_predicate(self.tcx)
-            });
+        let output_ty = expected.only_has_type(self).and_then(|ty| (!ty.needs_infer()).then(|| ty));
 
         (
             traits::Obligation::new(
@@ -368,7 +344,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         rhs_span: opt_input_expr.map(|expr| expr.span),
                         is_lit: opt_input_expr
                             .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
-                        output_pred,
+                        output_ty,
                     },
                 ),
                 self.param_env,
@@ -383,7 +359,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// In particular, it doesn't really do any probing: it simply constructs
     /// an obligation for a particular trait with the given self type and checks
     /// whether that trait is implemented.
-    #[instrument(level = "debug", skip(self, span, opt_input_types))]
+    #[instrument(level = "debug", skip(self, span))]
     pub(super) fn lookup_method_in_trait(
         &self,
         span: Span,
@@ -392,11 +368,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self_ty: Ty<'tcx>,
         opt_input_types: Option<&[Ty<'tcx>]>,
     ) -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
-        debug!(
-            "lookup_in_trait_adjusted(self_ty={:?}, m_name={}, trait_def_id={:?}, opt_input_types={:?})",
-            self_ty, m_name, trait_def_id, opt_input_types
-        );
-
         let (obligation, substs) =
             self.obligation_for_method(span, trait_def_id, self_ty, opt_input_types);
         self.construct_obligation_for_trait(
@@ -528,7 +499,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     rhs_span: opt_input_expr.map(|expr| expr.span),
                     is_lit: opt_input_expr
                         .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
-                    output_pred: None,
+                    output_ty: None,
                 },
             )
         } else {
@@ -576,7 +547,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// * `self_ty`:               the type to search within (`Foo`)
     /// * `self_ty_span`           the span for the type being searched within (span of `Foo`)
     /// * `expr_id`:               the [`hir::HirId`] of the expression composing the entire call
-    #[instrument(level = "debug", skip(self))]
+    #[instrument(level = "debug", skip(self), ret)]
     pub fn resolve_fully_qualified_call(
         &self,
         span: Span,
@@ -585,11 +556,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self_ty_span: Span,
         expr_id: hir::HirId,
     ) -> Result<(DefKind, DefId), MethodError<'tcx>> {
-        debug!(
-            "resolve_fully_qualified_call: method_name={:?} self_ty={:?} expr_id={:?}",
-            method_name, self_ty, expr_id,
-        );
-
         let tcx = self.tcx;
 
         // Check if we have an enum variant.
@@ -633,21 +599,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             &pick,
         );
 
-        debug!("resolve_fully_qualified_call: pick={:?}", pick);
+        debug!(?pick);
         {
             let mut typeck_results = self.typeck_results.borrow_mut();
             let used_trait_imports = Lrc::get_mut(&mut typeck_results.used_trait_imports).unwrap();
             for import_id in pick.import_ids {
-                debug!("resolve_fully_qualified_call: used_trait_import: {:?}", import_id);
+                debug!(used_trait_import=?import_id);
                 used_trait_imports.insert(import_id);
             }
         }
 
         let def_kind = pick.item.kind.as_def_kind();
-        debug!(
-            "resolve_fully_qualified_call: def_kind={:?}, def_id={:?}",
-            def_kind, pick.item.def_id
-        );
         tcx.check_stability(pick.item.def_id, Some(expr_id), span, Some(method_name.span));
         Ok((def_kind, pick.item.def_id))
     }
diff --git a/compiler/rustc_typeck/src/check/method/prelude2021.rs b/compiler/rustc_typeck/src/check/method/prelude2021.rs
index 7c68d9304055..392695cca684 100644
--- a/compiler/rustc_typeck/src/check/method/prelude2021.rs
+++ b/compiler/rustc_typeck/src/check/method/prelude2021.rs
@@ -160,7 +160,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     if precise {
                         let args = args
                             .iter()
-                            .skip(1)
                             .map(|arg| {
                                 let span = arg.span.find_ancestor_inside(sp).unwrap_or_default();
                                 format!(
diff --git a/compiler/rustc_typeck/src/check/method/probe.rs b/compiler/rustc_typeck/src/check/method/probe.rs
index d9870060a40b..6cd7ced01a3b 100644
--- a/compiler/rustc_typeck/src/check/method/probe.rs
+++ b/compiler/rustc_typeck/src/check/method/probe.rs
@@ -19,9 +19,9 @@ use rustc_infer::infer::{self, InferOk, TyCtxtInferExt};
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
 use rustc_middle::middle::stability;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
-use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::GenericParamDefKind;
 use rustc_middle::ty::{self, ParamEnvAnd, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeVisitable};
+use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::lev_distance::{
@@ -253,7 +253,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// would result in an error (basically, the same criteria we
     /// would use to decide if a method is a plausible fit for
     /// ambiguity purposes).
-    #[instrument(level = "debug", skip(self, scope_expr_id))]
+    #[instrument(level = "debug", skip(self))]
     pub fn probe_for_return_type(
         &self,
         span: Span,
@@ -262,10 +262,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self_ty: Ty<'tcx>,
         scope_expr_id: hir::HirId,
     ) -> Vec<ty::AssocItem> {
-        debug!(
-            "probe(self_ty={:?}, return_type={}, scope_expr_id={})",
-            self_ty, return_type, scope_expr_id
-        );
         let method_names = self
             .probe_op(
                 span,
@@ -299,7 +295,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .collect()
     }
 
-    #[instrument(level = "debug", skip(self, scope_expr_id))]
+    #[instrument(level = "debug", skip(self))]
     pub fn probe_for_name(
         &self,
         span: Span,
@@ -310,10 +306,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         scope_expr_id: hir::HirId,
         scope: ProbeScope,
     ) -> PickResult<'tcx> {
-        debug!(
-            "probe(self_ty={:?}, item_name={}, scope_expr_id={})",
-            self_ty, item_name, scope_expr_id
-        );
         self.probe_op(
             span,
             mode,
diff --git a/compiler/rustc_typeck/src/check/method/suggest.rs b/compiler/rustc_typeck/src/check/method/suggest.rs
index e99782fdc652..0e77ed0a4fe2 100644
--- a/compiler/rustc_typeck/src/check/method/suggest.rs
+++ b/compiler/rustc_typeck/src/check/method/suggest.rs
@@ -16,8 +16,8 @@ use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKi
 use rustc_middle::traits::util::supertraits;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::print::with_crate_prefix;
-use rustc_middle::ty::ToPolyTraitRef;
 use rustc_middle::ty::{self, DefIdTree, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{IsSuggestable, ToPolyTraitRef};
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Symbol;
 use rustc_span::{lev_distance, source_map, ExpnKind, FileName, MacroKind, Span};
@@ -30,7 +30,7 @@ use rustc_trait_selection::traits::{
 use std::cmp::Ordering;
 use std::iter;
 
-use super::probe::{Mode, ProbeScope};
+use super::probe::{IsSuggestion, Mode, ProbeScope};
 use super::{CandidateSource, MethodError, NoMatchData};
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
@@ -95,7 +95,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         item_name: Ident,
         source: SelfSource<'tcx>,
         error: MethodError<'tcx>,
-        args: Option<&'tcx [hir::Expr<'tcx>]>,
+        args: Option<(&'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>])>,
     ) -> Option<DiagnosticBuilder<'_, ErrorGuaranteed>> {
         // Avoid suggestions when we don't know what's going on.
         if rcvr_ty.references_error() {
@@ -537,7 +537,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 bound_spans.push((self.tcx.def_span(def.did()), msg))
                             }
                             // Point at the trait object that couldn't satisfy the bound.
-                            ty::Dynamic(preds, _) => {
+                            ty::Dynamic(preds, _, _) => {
                                 for pred in preds.iter() {
                                     match pred.skip_binder() {
                                         ty::ExistentialPredicate::Trait(tr) => bound_spans
@@ -998,7 +998,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         span,
                         rcvr_ty,
                         item_name,
-                        args.map(|args| args.len()),
+                        args.map(|(_, args)| args.len() + 1),
                         source,
                         out_of_scope_traits,
                         &unsatisfied_predicates,
@@ -1069,6 +1069,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                 }
 
+                self.check_for_deref_method(&mut err, source, rcvr_ty, item_name);
+
                 return Some(err);
             }
 
@@ -1159,7 +1161,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             _ => None,
         });
         if let Some((field, field_ty)) = field_receiver {
-            let scope = tcx.parent_module(self.body_id).to_def_id();
+            let scope = tcx.parent_module(self.body_id);
             let is_accessible = field.vis.is_accessible_from(scope, tcx);
 
             if is_accessible {
@@ -1651,6 +1653,62 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    fn check_for_deref_method(
+        &self,
+        err: &mut Diagnostic,
+        self_source: SelfSource<'tcx>,
+        rcvr_ty: Ty<'tcx>,
+        item_name: Ident,
+    ) {
+        let SelfSource::QPath(ty) = self_source else { return; };
+        for (deref_ty, _) in self.autoderef(rustc_span::DUMMY_SP, rcvr_ty).skip(1) {
+            if let Ok(pick) = self.probe_for_name(
+                ty.span,
+                Mode::Path,
+                item_name,
+                IsSuggestion(true),
+                deref_ty,
+                ty.hir_id,
+                ProbeScope::TraitsInScope,
+            ) {
+                if deref_ty.is_suggestable(self.tcx, true)
+                    // If this method receives `&self`, then the provided
+                    // argument _should_ coerce, so it's valid to suggest
+                    // just changing the path.
+                    && pick.item.fn_has_self_parameter
+                    && let Some(self_ty) =
+                        self.tcx.fn_sig(pick.item.def_id).inputs().skip_binder().get(0)
+                    && self_ty.is_ref()
+                {
+                    let suggested_path = match deref_ty.kind() {
+                        ty::Bool
+                        | ty::Char
+                        | ty::Int(_)
+                        | ty::Uint(_)
+                        | ty::Float(_)
+                        | ty::Adt(_, _)
+                        | ty::Str
+                        | ty::Projection(_)
+                        | ty::Param(_) => format!("{deref_ty}"),
+                        _ => format!("<{deref_ty}>"),
+                    };
+                    err.span_suggestion_verbose(
+                        ty.span,
+                        format!("the function `{item_name}` is implemented on `{deref_ty}`"),
+                        suggested_path,
+                        Applicability::MaybeIncorrect,
+                    );
+                } else {
+                    err.span_note(
+                        ty.span,
+                        format!("the function `{item_name}` is implemented on `{deref_ty}`"),
+                    );
+                }
+                return;
+            }
+        }
+    }
+
     /// Print out the type for use in value namespace.
     fn ty_to_value_string(&self, ty: Ty<'tcx>) -> String {
         match ty.kind() {
@@ -2019,7 +2077,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 Colon,
                                 Nothing,
                             }
-                            let ast_generics = hir.get_generics(id.owner).unwrap();
+                            let ast_generics = hir.get_generics(id.owner.def_id).unwrap();
                             let (sp, mut introducer) = if let Some(span) =
                                 ast_generics.bounds_span_for_suggestions(def_id)
                             {
@@ -2252,7 +2310,7 @@ pub fn all_traits(tcx: TyCtxt<'_>) -> Vec<TraitInfo> {
 
 fn print_disambiguation_help<'tcx>(
     item_name: Ident,
-    args: Option<&'tcx [hir::Expr<'tcx>]>,
+    args: Option<(&'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>])>,
     err: &mut Diagnostic,
     trait_name: String,
     rcvr_ty: Ty<'_>,
@@ -2264,7 +2322,7 @@ fn print_disambiguation_help<'tcx>(
     fn_has_self_parameter: bool,
 ) {
     let mut applicability = Applicability::MachineApplicable;
-    let (span, sugg) = if let (ty::AssocKind::Fn, Some(args)) = (kind, args) {
+    let (span, sugg) = if let (ty::AssocKind::Fn, Some((receiver, args))) = (kind, args) {
         let args = format!(
             "({}{})",
             if rcvr_ty.is_region_ptr() {
@@ -2272,7 +2330,8 @@ fn print_disambiguation_help<'tcx>(
             } else {
                 ""
             },
-            args.iter()
+            std::iter::once(receiver)
+                .chain(args.iter())
                 .map(|arg| source_map.span_to_snippet(arg.span).unwrap_or_else(|_| {
                     applicability = Applicability::HasPlaceholders;
                     "_".to_owned()
diff --git a/compiler/rustc_typeck/src/check/mod.rs b/compiler/rustc_typeck/src/check/mod.rs
index 3281dd8298bc..593a9776bde3 100644
--- a/compiler/rustc_typeck/src/check/mod.rs
+++ b/compiler/rustc_typeck/src/check/mod.rs
@@ -112,8 +112,8 @@ use rustc_hir::{HirIdMap, ImplicitSelfKind, Node};
 use rustc_index::bit_set::BitSet;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::{self, Ty, TyCtxt, UserType};
+use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_session::config;
 use rustc_session::parse::feature_err;
 use rustc_session::Session;
@@ -132,6 +132,7 @@ use crate::require_c_abi_if_c_variadic;
 use crate::util::common::indenter;
 
 use self::coercion::DynamicCoerceMany;
+use self::compare_method::collect_trait_impl_trait_tys;
 use self::region::region_scope_tree;
 pub use self::Expectation::*;
 
@@ -249,6 +250,7 @@ pub fn provide(providers: &mut Providers) {
         used_trait_imports,
         check_mod_item_types,
         region_scope_tree,
+        collect_trait_impl_trait_tys,
         ..*providers
     };
 }
@@ -341,7 +343,6 @@ fn diagnostic_only_typeck<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::T
     typeck_with_fallback(tcx, def_id, fallback)
 }
 
-#[instrument(skip(tcx, fallback))]
 fn typeck_with_fallback<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: LocalDefId,
@@ -365,7 +366,7 @@ fn typeck_with_fallback<'tcx>(
 
     let typeck_results = Inherited::build(tcx, def_id).enter(|inh| {
         let param_env = tcx.param_env(def_id);
-        let fcx = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
+        let mut fcx = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
             let fn_sig = if crate::collect::get_infer_ret_ty(&decl.output).is_some() {
                 let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
                 <dyn AstConv<'_>>::ty_of_fn(&fcx, id, header.unsafety, header.abi, decl, None, None)
@@ -458,13 +459,22 @@ fn typeck_with_fallback<'tcx>(
 
         // Closure and generator analysis may run after fallback
         // because they don't constrain other type variables.
+        // Closure analysis only runs on closures. Therefore they only need to fulfill non-const predicates (as of now)
+        let prev_constness = fcx.param_env.constness();
+        fcx.param_env = fcx.param_env.without_const();
         fcx.closure_analyze(body);
+        fcx.param_env = fcx.param_env.with_constness(prev_constness);
         assert!(fcx.deferred_call_resolutions.borrow().is_empty());
         // Before the generator analysis, temporary scopes shall be marked to provide more
         // precise information on types to be captured.
         fcx.resolve_rvalue_scopes(def_id.to_def_id());
         fcx.resolve_generator_interiors(def_id.to_def_id());
 
+        for (ty, span, code) in fcx.deferred_sized_obligations.borrow_mut().drain(..) {
+            let ty = fcx.normalize_ty(span, ty);
+            fcx.require_type_is_sized(ty, span, code);
+        }
+
         fcx.select_all_obligations_or_error();
 
         if !fcx.infcx.is_tainted_by_errors() {
@@ -509,7 +519,7 @@ fn get_owner_return_paths<'tcx>(
     def_id: LocalDefId,
 ) -> Option<(LocalDefId, ReturnsVisitor<'tcx>)> {
     let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-    let parent_id = tcx.hir().get_parent_item(hir_id);
+    let parent_id = tcx.hir().get_parent_item(hir_id).def_id;
     tcx.hir().find_by_def_id(parent_id).and_then(|node| node.body_id()).map(|body_id| {
         let body = tcx.hir().body(body_id);
         let mut visitor = ReturnsVisitor::default();
diff --git a/compiler/rustc_typeck/src/check/op.rs b/compiler/rustc_typeck/src/check/op.rs
index 952086e898fc..4754717c29ab 100644
--- a/compiler/rustc_typeck/src/check/op.rs
+++ b/compiler/rustc_typeck/src/check/op.rs
@@ -11,9 +11,8 @@ use rustc_infer::traits::ObligationCauseCode;
 use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability,
 };
-use rustc_middle::ty::{
-    self, Ty, TyCtxt, TypeFolder, TypeSuperFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitor,
-};
+use rustc_middle::ty::print::with_no_trimmed_paths;
+use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt, TypeFolder, TypeSuperFoldable, TypeVisitable};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
@@ -22,8 +21,6 @@ use rustc_trait_selection::traits::error_reporting::suggestions::InferCtxtExt as
 use rustc_trait_selection::traits::{FulfillmentError, TraitEngine, TraitEngineExt};
 use rustc_type_ir::sty::TyKind::*;
 
-use std::ops::ControlFlow;
-
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Checks a `a <op>= b`
     pub fn check_binop_assign(
@@ -57,9 +54,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     )
                     .is_ok()
                 {
-                    // Suppress this error, since we already emitted
-                    // a deref suggestion in check_overloaded_binop
-                    err.downgrade_to_delayed_bug();
+                    // If LHS += RHS is an error, but *LHS += RHS is successful, then we will have
+                    // emitted a better suggestion during error handling in check_overloaded_binop.
+                    if self
+                        .lookup_op_method(
+                            lhs_ty,
+                            Some(rhs_ty),
+                            Some(rhs),
+                            Op::Binary(op, IsAssign::Yes),
+                            expected,
+                        )
+                        .is_err()
+                    {
+                        err.downgrade_to_delayed_bug();
+                    } else {
+                        // Otherwise, it's valid to suggest dereferencing the LHS here.
+                        err.span_suggestion_verbose(
+                            lhs.span.shrink_to_lo(),
+                            "consider dereferencing the left-hand side of this operation",
+                            "*",
+                            Applicability::MaybeIncorrect,
+                        );
+                    }
                 }
             }
         });
@@ -294,8 +310,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // error types are considered "builtin"
             Err(_) if lhs_ty.references_error() || rhs_ty.references_error() => self.tcx.ty_error(),
             Err(errors) => {
-                let source_map = self.tcx.sess.source_map();
-                let (mut err, missing_trait, use_output) = match is_assign {
+                let (_, trait_def_id) =
+                    lang_item_for_op(self.tcx, Op::Binary(op, is_assign), op.span);
+                let missing_trait = trait_def_id
+                    .map(|def_id| with_no_trimmed_paths!(self.tcx.def_path_str(def_id)));
+                let (mut err, output_def_id) = match is_assign {
                     IsAssign::Yes => {
                         let mut err = struct_span_err!(
                             self.tcx.sess,
@@ -309,112 +328,63 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             lhs_expr.span,
                             format!("cannot use `{}=` on type `{}`", op.node.as_str(), lhs_ty),
                         );
-                        let missing_trait = match op.node {
-                            hir::BinOpKind::Add => Some("std::ops::AddAssign"),
-                            hir::BinOpKind::Sub => Some("std::ops::SubAssign"),
-                            hir::BinOpKind::Mul => Some("std::ops::MulAssign"),
-                            hir::BinOpKind::Div => Some("std::ops::DivAssign"),
-                            hir::BinOpKind::Rem => Some("std::ops::RemAssign"),
-                            hir::BinOpKind::BitAnd => Some("std::ops::BitAndAssign"),
-                            hir::BinOpKind::BitXor => Some("std::ops::BitXorAssign"),
-                            hir::BinOpKind::BitOr => Some("std::ops::BitOrAssign"),
-                            hir::BinOpKind::Shl => Some("std::ops::ShlAssign"),
-                            hir::BinOpKind::Shr => Some("std::ops::ShrAssign"),
-                            _ => None,
-                        };
                         self.note_unmet_impls_on_type(&mut err, errors);
-                        (err, missing_trait, false)
+                        (err, None)
                     }
                     IsAssign::No => {
-                        let (message, missing_trait, use_output) = match op.node {
-                            hir::BinOpKind::Add => (
-                                format!("cannot add `{rhs_ty}` to `{lhs_ty}`"),
-                                Some("std::ops::Add"),
-                                true,
-                            ),
-                            hir::BinOpKind::Sub => (
-                                format!("cannot subtract `{rhs_ty}` from `{lhs_ty}`"),
-                                Some("std::ops::Sub"),
-                                true,
-                            ),
-                            hir::BinOpKind::Mul => (
-                                format!("cannot multiply `{lhs_ty}` by `{rhs_ty}`"),
-                                Some("std::ops::Mul"),
-                                true,
-                            ),
-                            hir::BinOpKind::Div => (
-                                format!("cannot divide `{lhs_ty}` by `{rhs_ty}`"),
-                                Some("std::ops::Div"),
-                                true,
-                            ),
-                            hir::BinOpKind::Rem => (
-                                format!("cannot mod `{lhs_ty}` by `{rhs_ty}`"),
-                                Some("std::ops::Rem"),
-                                true,
-                            ),
-                            hir::BinOpKind::BitAnd => (
-                                format!("no implementation for `{lhs_ty} & {rhs_ty}`"),
-                                Some("std::ops::BitAnd"),
-                                true,
-                            ),
-                            hir::BinOpKind::BitXor => (
-                                format!("no implementation for `{lhs_ty} ^ {rhs_ty}`"),
-                                Some("std::ops::BitXor"),
-                                true,
-                            ),
-                            hir::BinOpKind::BitOr => (
-                                format!("no implementation for `{lhs_ty} | {rhs_ty}`"),
-                                Some("std::ops::BitOr"),
-                                true,
-                            ),
-                            hir::BinOpKind::Shl => (
-                                format!("no implementation for `{lhs_ty} << {rhs_ty}`"),
-                                Some("std::ops::Shl"),
-                                true,
-                            ),
-                            hir::BinOpKind::Shr => (
-                                format!("no implementation for `{lhs_ty} >> {rhs_ty}`"),
-                                Some("std::ops::Shr"),
-                                true,
-                            ),
-                            hir::BinOpKind::Eq | hir::BinOpKind::Ne => (
-                                format!(
-                                    "binary operation `{}` cannot be applied to type `{}`",
-                                    op.node.as_str(),
-                                    lhs_ty
-                                ),
-                                Some("std::cmp::PartialEq"),
-                                false,
-                            ),
-                            hir::BinOpKind::Lt
-                            | hir::BinOpKind::Le
-                            | hir::BinOpKind::Gt
-                            | hir::BinOpKind::Ge => (
-                                format!(
-                                    "binary operation `{}` cannot be applied to type `{}`",
-                                    op.node.as_str(),
-                                    lhs_ty
-                                ),
-                                Some("std::cmp::PartialOrd"),
-                                false,
-                            ),
-                            _ => (
-                                format!(
-                                    "binary operation `{}` cannot be applied to type `{}`",
-                                    op.node.as_str(),
-                                    lhs_ty
-                                ),
-                                None,
-                                false,
+                        let message = match op.node {
+                            hir::BinOpKind::Add => {
+                                format!("cannot add `{rhs_ty}` to `{lhs_ty}`")
+                            }
+                            hir::BinOpKind::Sub => {
+                                format!("cannot subtract `{rhs_ty}` from `{lhs_ty}`")
+                            }
+                            hir::BinOpKind::Mul => {
+                                format!("cannot multiply `{lhs_ty}` by `{rhs_ty}`")
+                            }
+                            hir::BinOpKind::Div => {
+                                format!("cannot divide `{lhs_ty}` by `{rhs_ty}`")
+                            }
+                            hir::BinOpKind::Rem => {
+                                format!("cannot mod `{lhs_ty}` by `{rhs_ty}`")
+                            }
+                            hir::BinOpKind::BitAnd => {
+                                format!("no implementation for `{lhs_ty} & {rhs_ty}`")
+                            }
+                            hir::BinOpKind::BitXor => {
+                                format!("no implementation for `{lhs_ty} ^ {rhs_ty}`")
+                            }
+                            hir::BinOpKind::BitOr => {
+                                format!("no implementation for `{lhs_ty} | {rhs_ty}`")
+                            }
+                            hir::BinOpKind::Shl => {
+                                format!("no implementation for `{lhs_ty} << {rhs_ty}`")
+                            }
+                            hir::BinOpKind::Shr => {
+                                format!("no implementation for `{lhs_ty} >> {rhs_ty}`")
+                            }
+                            _ => format!(
+                                "binary operation `{}` cannot be applied to type `{}`",
+                                op.node.as_str(),
+                                lhs_ty
                             ),
                         };
+                        let output_def_id = trait_def_id.and_then(|def_id| {
+                            self.tcx
+                                .associated_item_def_ids(def_id)
+                                .iter()
+                                .find(|item_def_id| {
+                                    self.tcx.associated_item(*item_def_id).name == sym::Output
+                                })
+                                .cloned()
+                        });
                         let mut err = struct_span_err!(self.tcx.sess, op.span, E0369, "{message}");
                         if !lhs_expr.span.eq(&rhs_expr.span) {
                             err.span_label(lhs_expr.span, lhs_ty.to_string());
                             err.span_label(rhs_expr.span, rhs_ty.to_string());
                         }
                         self.note_unmet_impls_on_type(&mut err, errors);
-                        (err, missing_trait, use_output)
+                        (err, output_def_id)
                     }
                 };
 
@@ -429,24 +399,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         )
                         .is_ok()
                     {
-                        if let Ok(lstring) = source_map.span_to_snippet(lhs_expr.span) {
-                            let msg = &format!(
-                                "`{}{}` can be used on `{}`, you can dereference `{}`",
-                                op.node.as_str(),
-                                match is_assign {
-                                    IsAssign::Yes => "=",
-                                    IsAssign::No => "",
-                                },
-                                lhs_deref_ty.peel_refs(),
-                                lstring,
-                            );
-                            err.span_suggestion_verbose(
-                                lhs_expr.span.shrink_to_lo(),
-                                msg,
-                                "*",
-                                rustc_errors::Applicability::MachineApplicable,
-                            );
-                        }
+                        let msg = &format!(
+                            "`{}{}` can be used on `{}` if you dereference the left-hand side",
+                            op.node.as_str(),
+                            match is_assign {
+                                IsAssign::Yes => "=",
+                                IsAssign::No => "",
+                            },
+                            lhs_deref_ty,
+                        );
+                        err.span_suggestion_verbose(
+                            lhs_expr.span.shrink_to_lo(),
+                            msg,
+                            "*",
+                            rustc_errors::Applicability::MachineApplicable,
+                        );
                     }
                 };
 
@@ -495,9 +462,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
 
                 if let Some(missing_trait) = missing_trait {
-                    let mut visitor = TypeParamVisitor(vec![]);
-                    visitor.visit_ty(lhs_ty);
-
                     if op.node == hir::BinOpKind::Add
                         && self.check_str_addition(
                             lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, is_assign, op,
@@ -506,7 +470,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         // This has nothing here because it means we did string
                         // concatenation (e.g., "Hello " + "World!"). This means
                         // we don't want the note in the else clause to be emitted
-                    } else if let [ty] = &visitor.0[..] {
+                    } else if lhs_ty.has_param_types_or_consts() {
                         // Look for a TraitPredicate in the Fulfillment errors,
                         // and use it to generate a suggestion.
                         //
@@ -528,12 +492,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 if let Some(trait_pred) =
                                     error.obligation.predicate.to_opt_poly_trait_pred()
                                 {
-                                    let proj_pred = match error.obligation.cause.code() {
+                                    let output_associated_item = match error.obligation.cause.code()
+                                    {
                                         ObligationCauseCode::BinOp {
-                                            output_pred: Some(output_pred),
+                                            output_ty: Some(output_ty),
                                             ..
-                                        } if use_output => {
-                                            output_pred.to_opt_poly_projection_pred()
+                                        } => {
+                                            // Make sure that we're attaching `Output = ..` to the right trait predicate
+                                            if let Some(output_def_id) = output_def_id
+                                                && let Some(trait_def_id) = trait_def_id
+                                                && self.tcx.parent(output_def_id) == trait_def_id
+                                            {
+                                                Some(("Output", *output_ty))
+                                            } else {
+                                                None
+                                            }
                                         }
                                         _ => None,
                                     };
@@ -541,12 +514,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                     self.suggest_restricting_param_bound(
                                         &mut err,
                                         trait_pred,
-                                        proj_pred,
+                                        output_associated_item,
                                         self.body_id,
                                     );
                                 }
                             }
-                        } else if *ty != lhs_ty {
+                        } else {
                             // When we know that a missing bound is responsible, we don't show
                             // this note as it is redundant.
                             err.note(&format!(
@@ -683,14 +656,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         format!("cannot apply unary operator `{}`", op.as_str()),
                     );
 
-                    let mut visitor = TypeParamVisitor(vec![]);
-                    visitor.visit_ty(operand_ty);
-                    if let [_] = &visitor.0[..] && let ty::Param(_) = *operand_ty.kind() {
-                        let predicates = errors
-                            .iter()
-                            .filter_map(|error| {
-                                error.obligation.predicate.to_opt_poly_trait_pred()
-                            });
+                    if operand_ty.has_param_types_or_consts() {
+                        let predicates = errors.iter().filter_map(|error| {
+                            error.obligation.predicate.to_opt_poly_trait_pred()
+                        });
                         for pred in predicates {
                             self.suggest_restricting_param_bound(
                                 &mut err,
@@ -758,64 +727,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         op: Op,
         expected: Expectation<'tcx>,
     ) -> Result<MethodCallee<'tcx>, Vec<FulfillmentError<'tcx>>> {
-        let lang = self.tcx.lang_items();
-
         let span = match op {
             Op::Binary(op, _) => op.span,
             Op::Unary(_, span) => span,
         };
-        let (opname, trait_did) = if let Op::Binary(op, IsAssign::Yes) = op {
-            match op.node {
-                hir::BinOpKind::Add => (sym::add_assign, lang.add_assign_trait()),
-                hir::BinOpKind::Sub => (sym::sub_assign, lang.sub_assign_trait()),
-                hir::BinOpKind::Mul => (sym::mul_assign, lang.mul_assign_trait()),
-                hir::BinOpKind::Div => (sym::div_assign, lang.div_assign_trait()),
-                hir::BinOpKind::Rem => (sym::rem_assign, lang.rem_assign_trait()),
-                hir::BinOpKind::BitXor => (sym::bitxor_assign, lang.bitxor_assign_trait()),
-                hir::BinOpKind::BitAnd => (sym::bitand_assign, lang.bitand_assign_trait()),
-                hir::BinOpKind::BitOr => (sym::bitor_assign, lang.bitor_assign_trait()),
-                hir::BinOpKind::Shl => (sym::shl_assign, lang.shl_assign_trait()),
-                hir::BinOpKind::Shr => (sym::shr_assign, lang.shr_assign_trait()),
-                hir::BinOpKind::Lt
-                | hir::BinOpKind::Le
-                | hir::BinOpKind::Ge
-                | hir::BinOpKind::Gt
-                | hir::BinOpKind::Eq
-                | hir::BinOpKind::Ne
-                | hir::BinOpKind::And
-                | hir::BinOpKind::Or => {
-                    span_bug!(span, "impossible assignment operation: {}=", op.node.as_str())
-                }
-            }
-        } else if let Op::Binary(op, IsAssign::No) = op {
-            match op.node {
-                hir::BinOpKind::Add => (sym::add, lang.add_trait()),
-                hir::BinOpKind::Sub => (sym::sub, lang.sub_trait()),
-                hir::BinOpKind::Mul => (sym::mul, lang.mul_trait()),
-                hir::BinOpKind::Div => (sym::div, lang.div_trait()),
-                hir::BinOpKind::Rem => (sym::rem, lang.rem_trait()),
-                hir::BinOpKind::BitXor => (sym::bitxor, lang.bitxor_trait()),
-                hir::BinOpKind::BitAnd => (sym::bitand, lang.bitand_trait()),
-                hir::BinOpKind::BitOr => (sym::bitor, lang.bitor_trait()),
-                hir::BinOpKind::Shl => (sym::shl, lang.shl_trait()),
-                hir::BinOpKind::Shr => (sym::shr, lang.shr_trait()),
-                hir::BinOpKind::Lt => (sym::lt, lang.partial_ord_trait()),
-                hir::BinOpKind::Le => (sym::le, lang.partial_ord_trait()),
-                hir::BinOpKind::Ge => (sym::ge, lang.partial_ord_trait()),
-                hir::BinOpKind::Gt => (sym::gt, lang.partial_ord_trait()),
-                hir::BinOpKind::Eq => (sym::eq, lang.eq_trait()),
-                hir::BinOpKind::Ne => (sym::ne, lang.eq_trait()),
-                hir::BinOpKind::And | hir::BinOpKind::Or => {
-                    span_bug!(span, "&& and || are not overloadable")
-                }
-            }
-        } else if let Op::Unary(hir::UnOp::Not, _) = op {
-            (sym::not, lang.not_trait())
-        } else if let Op::Unary(hir::UnOp::Neg, _) = op {
-            (sym::neg, lang.neg_trait())
-        } else {
-            bug!("lookup_op_method: op not supported: {:?}", op)
-        };
+        let (opname, trait_did) = lang_item_for_op(self.tcx, op, span);
 
         debug!(
             "lookup_op_method(lhs_ty={:?}, op={:?}, opname={:?}, trait_did={:?})",
@@ -876,6 +792,66 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 }
 
+fn lang_item_for_op(
+    tcx: TyCtxt<'_>,
+    op: Op,
+    span: Span,
+) -> (rustc_span::Symbol, Option<hir::def_id::DefId>) {
+    let lang = tcx.lang_items();
+    if let Op::Binary(op, IsAssign::Yes) = op {
+        match op.node {
+            hir::BinOpKind::Add => (sym::add_assign, lang.add_assign_trait()),
+            hir::BinOpKind::Sub => (sym::sub_assign, lang.sub_assign_trait()),
+            hir::BinOpKind::Mul => (sym::mul_assign, lang.mul_assign_trait()),
+            hir::BinOpKind::Div => (sym::div_assign, lang.div_assign_trait()),
+            hir::BinOpKind::Rem => (sym::rem_assign, lang.rem_assign_trait()),
+            hir::BinOpKind::BitXor => (sym::bitxor_assign, lang.bitxor_assign_trait()),
+            hir::BinOpKind::BitAnd => (sym::bitand_assign, lang.bitand_assign_trait()),
+            hir::BinOpKind::BitOr => (sym::bitor_assign, lang.bitor_assign_trait()),
+            hir::BinOpKind::Shl => (sym::shl_assign, lang.shl_assign_trait()),
+            hir::BinOpKind::Shr => (sym::shr_assign, lang.shr_assign_trait()),
+            hir::BinOpKind::Lt
+            | hir::BinOpKind::Le
+            | hir::BinOpKind::Ge
+            | hir::BinOpKind::Gt
+            | hir::BinOpKind::Eq
+            | hir::BinOpKind::Ne
+            | hir::BinOpKind::And
+            | hir::BinOpKind::Or => {
+                span_bug!(span, "impossible assignment operation: {}=", op.node.as_str())
+            }
+        }
+    } else if let Op::Binary(op, IsAssign::No) = op {
+        match op.node {
+            hir::BinOpKind::Add => (sym::add, lang.add_trait()),
+            hir::BinOpKind::Sub => (sym::sub, lang.sub_trait()),
+            hir::BinOpKind::Mul => (sym::mul, lang.mul_trait()),
+            hir::BinOpKind::Div => (sym::div, lang.div_trait()),
+            hir::BinOpKind::Rem => (sym::rem, lang.rem_trait()),
+            hir::BinOpKind::BitXor => (sym::bitxor, lang.bitxor_trait()),
+            hir::BinOpKind::BitAnd => (sym::bitand, lang.bitand_trait()),
+            hir::BinOpKind::BitOr => (sym::bitor, lang.bitor_trait()),
+            hir::BinOpKind::Shl => (sym::shl, lang.shl_trait()),
+            hir::BinOpKind::Shr => (sym::shr, lang.shr_trait()),
+            hir::BinOpKind::Lt => (sym::lt, lang.partial_ord_trait()),
+            hir::BinOpKind::Le => (sym::le, lang.partial_ord_trait()),
+            hir::BinOpKind::Ge => (sym::ge, lang.partial_ord_trait()),
+            hir::BinOpKind::Gt => (sym::gt, lang.partial_ord_trait()),
+            hir::BinOpKind::Eq => (sym::eq, lang.eq_trait()),
+            hir::BinOpKind::Ne => (sym::ne, lang.eq_trait()),
+            hir::BinOpKind::And | hir::BinOpKind::Or => {
+                span_bug!(span, "&& and || are not overloadable")
+            }
+        }
+    } else if let Op::Unary(hir::UnOp::Not, _) = op {
+        (sym::not, lang.not_trait())
+    } else if let Op::Unary(hir::UnOp::Neg, _) = op {
+        (sym::neg, lang.neg_trait())
+    } else {
+        bug!("lookup_op_method: op not supported: {:?}", op)
+    }
+}
+
 // Binary operator categories. These categories summarize the behavior
 // with respect to the builtin operations supported.
 enum BinOpCategory {
@@ -998,17 +974,6 @@ fn is_builtin_binop<'tcx>(lhs: Ty<'tcx>, rhs: Ty<'tcx>, op: hir::BinOp) -> bool
     }
 }
 
-struct TypeParamVisitor<'tcx>(Vec<Ty<'tcx>>);
-
-impl<'tcx> TypeVisitor<'tcx> for TypeParamVisitor<'tcx> {
-    fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-        if let ty::Param(_) = ty.kind() {
-            self.0.push(ty);
-        }
-        ty.super_visit_with(self)
-    }
-}
-
 struct TypeParamEraser<'a, 'tcx>(&'a FnCtxt<'a, 'tcx>, Span);
 
 impl<'tcx> TypeFolder<'tcx> for TypeParamEraser<'_, 'tcx> {
diff --git a/compiler/rustc_typeck/src/check/pat.rs b/compiler/rustc_typeck/src/check/pat.rs
index 6dcc364bb50f..8906b622b68e 100644
--- a/compiler/rustc_typeck/src/check/pat.rs
+++ b/compiler/rustc_typeck/src/check/pat.rs
@@ -569,7 +569,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) -> Ty<'tcx> {
         // Determine the binding mode...
         let bm = match ba {
-            hir::BindingAnnotation::Unannotated => def_bm,
+            hir::BindingAnnotation::NONE => def_bm,
             _ => BindingMode::convert(ba),
         };
         // ...and store it in a side table:
@@ -655,7 +655,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         ba: hir::BindingAnnotation,
     ) {
         match (expected.kind(), actual.kind(), ba) {
-            (ty::Ref(_, inner_ty, _), _, hir::BindingAnnotation::Unannotated)
+            (ty::Ref(_, inner_ty, _), _, hir::BindingAnnotation::NONE)
                 if self.can_eq(self.param_env, *inner_ty, actual).is_ok() =>
             {
                 err.span_suggestion_verbose(
@@ -665,7 +665,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     Applicability::MaybeIncorrect,
                 );
             }
-            (_, ty::Ref(_, inner_ty, _), hir::BindingAnnotation::Ref)
+            (_, ty::Ref(_, inner_ty, _), hir::BindingAnnotation::REF)
                 if self.can_eq(self.param_env, expected, *inner_ty).is_ok() =>
             {
                 err.span_suggestion_verbose(
@@ -981,7 +981,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         pat: &'tcx Pat<'tcx>,
         qpath: &'tcx hir::QPath<'tcx>,
         subpats: &'tcx [Pat<'tcx>],
-        ddpos: Option<usize>,
+        ddpos: hir::DotDotPos,
         expected: Ty<'tcx>,
         def_bm: BindingMode,
         ti: TopInfo<'tcx>,
@@ -1066,7 +1066,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Type-check subpatterns.
         if subpats.len() == variant.fields.len()
-            || subpats.len() < variant.fields.len() && ddpos.is_some()
+            || subpats.len() < variant.fields.len() && ddpos.as_opt_usize().is_some()
         {
             let ty::Adt(_, substs) = pat_ty.kind() else {
                 bug!("unexpected pattern type {:?}", pat_ty);
@@ -1254,14 +1254,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         span: Span,
         elements: &'tcx [Pat<'tcx>],
-        ddpos: Option<usize>,
+        ddpos: hir::DotDotPos,
         expected: Ty<'tcx>,
         def_bm: BindingMode,
         ti: TopInfo<'tcx>,
     ) -> Ty<'tcx> {
         let tcx = self.tcx;
         let mut expected_len = elements.len();
-        if ddpos.is_some() {
+        if ddpos.as_opt_usize().is_some() {
             // Require known type only when `..` is present.
             if let ty::Tuple(tys) = self.structurally_resolved_type(span, expected).kind() {
                 expected_len = tys.len();
@@ -1397,7 +1397,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .iter()
                 .copied()
                 .filter(|(field, _)| {
-                    field.vis.is_accessible_from(tcx.parent_module(pat.hir_id).to_def_id(), tcx)
+                    field.vis.is_accessible_from(tcx.parent_module(pat.hir_id), tcx)
                         && !matches!(
                             tcx.eval_stability(field.did, None, DUMMY_SP, None),
                             EvalResult::Deny { .. }
diff --git a/compiler/rustc_typeck/src/check/region.rs b/compiler/rustc_typeck/src/check/region.rs
index 0081e9049eec..b89db79bef8d 100644
--- a/compiler/rustc_typeck/src/check/region.rs
+++ b/compiler/rustc_typeck/src/check/region.rs
@@ -126,6 +126,29 @@ fn resolve_block<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, blk: &'tcx h
 
         for (i, statement) in blk.stmts.iter().enumerate() {
             match statement.kind {
+                hir::StmtKind::Local(hir::Local { els: Some(els), .. }) => {
+                    // Let-else has a special lexical structure for variables.
+                    // First we take a checkpoint of the current scope context here.
+                    let mut prev_cx = visitor.cx;
+
+                    visitor.enter_scope(Scope {
+                        id: blk.hir_id.local_id,
+                        data: ScopeData::Remainder(FirstStatementIndex::new(i)),
+                    });
+                    visitor.cx.var_parent = visitor.cx.parent;
+                    visitor.visit_stmt(statement);
+                    // We need to back out temporarily to the last enclosing scope
+                    // for the `else` block, so that even the temporaries receiving
+                    // extended lifetime will be dropped inside this block.
+                    // We are visiting the `else` block in this order so that
+                    // the sequence of visits agree with the order in the default
+                    // `hir::intravisit` visitor.
+                    mem::swap(&mut prev_cx, &mut visitor.cx);
+                    visitor.terminating_scopes.insert(els.hir_id.local_id);
+                    visitor.visit_block(els);
+                    // From now on, we continue normally.
+                    visitor.cx = prev_cx;
+                }
                 hir::StmtKind::Local(..) | hir::StmtKind::Item(..) => {
                     // Each declaration introduces a subscope for bindings
                     // introduced by the declaration; this subscope covers a
@@ -138,10 +161,10 @@ fn resolve_block<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, blk: &'tcx h
                         data: ScopeData::Remainder(FirstStatementIndex::new(i)),
                     });
                     visitor.cx.var_parent = visitor.cx.parent;
+                    visitor.visit_stmt(statement)
                 }
-                hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => {}
+                hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => visitor.visit_stmt(statement),
             }
-            visitor.visit_stmt(statement)
         }
         walk_list!(visitor, visit_expr, &blk.expr);
     }
@@ -460,7 +483,6 @@ fn resolve_local<'tcx>(
     visitor: &mut RegionResolutionVisitor<'tcx>,
     pat: Option<&'tcx hir::Pat<'tcx>>,
     init: Option<&'tcx hir::Expr<'tcx>>,
-    els: Option<&'tcx hir::Block<'tcx>>,
 ) {
     debug!("resolve_local(pat={:?}, init={:?})", pat, init);
 
@@ -547,9 +569,6 @@ fn resolve_local<'tcx>(
     if let Some(pat) = pat {
         visitor.visit_pat(pat);
     }
-    if let Some(els) = els {
-        visitor.visit_block(els);
-    }
 
     /// Returns `true` if `pat` match the `P&` non-terminal.
     ///
@@ -587,8 +606,7 @@ fn resolve_local<'tcx>(
         // & expression, and its lifetime would be extended to the end of the block (due
         // to a different rule, not the below code).
         match pat.kind {
-            PatKind::Binding(hir::BindingAnnotation::Ref, ..)
-            | PatKind::Binding(hir::BindingAnnotation::RefMut, ..) => true,
+            PatKind::Binding(hir::BindingAnnotation(hir::ByRef::Yes, _), ..) => true,
 
             PatKind::Struct(_, ref field_pats, _) => {
                 field_pats.iter().any(|fp| is_binding_pat(&fp.pat))
@@ -607,10 +625,7 @@ fn resolve_local<'tcx>(
             PatKind::Box(ref subpat) => is_binding_pat(&subpat),
 
             PatKind::Ref(_, _)
-            | PatKind::Binding(
-                hir::BindingAnnotation::Unannotated | hir::BindingAnnotation::Mutable,
-                ..,
-            )
+            | PatKind::Binding(hir::BindingAnnotation(hir::ByRef::No, _), ..)
             | PatKind::Wild
             | PatKind::Path(_)
             | PatKind::Lit(_)
@@ -770,7 +785,7 @@ impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> {
             // (i.e., `'static`), which means that after `g` returns, it drops,
             // and all the associated destruction scope rules apply.
             self.cx.var_parent = None;
-            resolve_local(self, None, Some(&body.value), None);
+            resolve_local(self, None, Some(&body.value));
         }
 
         if body.generator_kind.is_some() {
@@ -797,7 +812,7 @@ impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> {
         resolve_expr(self, ex);
     }
     fn visit_local(&mut self, l: &'tcx Local<'tcx>) {
-        resolve_local(self, Some(&l.pat), l.init, l.els)
+        resolve_local(self, Some(&l.pat), l.init)
     }
 }
 
diff --git a/compiler/rustc_typeck/src/check/upvar.rs b/compiler/rustc_typeck/src/check/upvar.rs
index 0afc153300bf..0b207a6c0bee 100644
--- a/compiler/rustc_typeck/src/check/upvar.rs
+++ b/compiler/rustc_typeck/src/check/upvar.rs
@@ -2024,6 +2024,10 @@ fn should_do_rust_2021_incompatible_closure_captures_analysis(
     tcx: TyCtxt<'_>,
     closure_id: hir::HirId,
 ) -> bool {
+    if tcx.sess.rust_2021() {
+        return false;
+    }
+
     let (level, _) =
         tcx.lint_level_at_node(lint::builtin::RUST_2021_INCOMPATIBLE_CLOSURE_CAPTURES, closure_id);
 
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
index ba42453bd60e..7965ec1b43f4 100644
--- a/compiler/rustc_typeck/src/check/wfcheck.rs
+++ b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -1,4 +1,5 @@
 use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter};
+use hir::def::DefKind;
 use rustc_ast as ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
@@ -9,13 +10,14 @@ use rustc_hir::ItemKind;
 use rustc_infer::infer::outlives::env::{OutlivesEnvironment, RegionBoundPairs};
 use rustc_infer::infer::outlives::obligations::TypeOutlives;
 use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt};
+use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts, Subst};
 use rustc_middle::ty::trait_def::TraitSpecializationKind;
 use rustc_middle::ty::{
     self, AdtKind, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TyCtxt, TypeFoldable,
     TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
+use rustc_middle::ty::{GenericArgKind, InternalSubsts};
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
@@ -114,7 +116,7 @@ pub(super) fn enter_wf_checking_ctxt<'tcx, F>(
     })
 }
 
-fn check_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
+fn check_well_formed(tcx: TyCtxt<'_>, def_id: hir::OwnerId) {
     let node = tcx.hir().expect_owner(def_id);
     match node {
         hir::OwnerNode::Crate(_) => {}
@@ -146,7 +148,7 @@ fn check_well_formed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
 /// the types first.
 #[instrument(skip(tcx), level = "debug")]
 fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
-    let def_id = item.def_id;
+    let def_id = item.def_id.def_id;
 
     debug!(
         ?item.def_id,
@@ -173,7 +175,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
         // for `T`
         hir::ItemKind::Impl(ref impl_) => {
             let is_auto = tcx
-                .impl_trait_ref(item.def_id)
+                .impl_trait_ref(def_id)
                 .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.def_id));
             if let (hir::Defaultness::Default { .. }, true) = (impl_.defaultness, is_auto) {
                 let sp = impl_.of_trait.as_ref().map_or(item.span, |t| t.path.span);
@@ -209,13 +211,13 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
             }
         }
         hir::ItemKind::Fn(ref sig, ..) => {
-            check_item_fn(tcx, item.def_id, item.ident, item.span, sig.decl);
+            check_item_fn(tcx, def_id, item.ident, item.span, sig.decl);
         }
         hir::ItemKind::Static(ty, ..) => {
-            check_item_type(tcx, item.def_id, ty.span, false);
+            check_item_type(tcx, def_id, ty.span, false);
         }
         hir::ItemKind::Const(ty, ..) => {
-            check_item_type(tcx, item.def_id, ty.span, false);
+            check_item_type(tcx, def_id, ty.span, false);
         }
         hir::ItemKind::Struct(ref struct_def, ref ast_generics) => {
             check_type_defn(tcx, item, false, |wfcx| vec![wfcx.non_enum_variant(struct_def)]);
@@ -245,7 +247,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
 }
 
 fn check_foreign_item(tcx: TyCtxt<'_>, item: &hir::ForeignItem<'_>) {
-    let def_id = item.def_id;
+    let def_id = item.def_id.def_id;
 
     debug!(
         ?item.def_id,
@@ -254,15 +256,15 @@ fn check_foreign_item(tcx: TyCtxt<'_>, item: &hir::ForeignItem<'_>) {
 
     match item.kind {
         hir::ForeignItemKind::Fn(decl, ..) => {
-            check_item_fn(tcx, item.def_id, item.ident, item.span, decl)
+            check_item_fn(tcx, def_id, item.ident, item.span, decl)
         }
-        hir::ForeignItemKind::Static(ty, ..) => check_item_type(tcx, item.def_id, ty.span, true),
+        hir::ForeignItemKind::Static(ty, ..) => check_item_type(tcx, def_id, ty.span, true),
         hir::ForeignItemKind::Type => (),
     }
 }
 
 fn check_trait_item(tcx: TyCtxt<'_>, trait_item: &hir::TraitItem<'_>) {
-    let def_id = trait_item.def_id;
+    let def_id = trait_item.def_id.def_id;
 
     let (method_sig, span) = match trait_item.kind {
         hir::TraitItemKind::Fn(ref sig, _) => (Some(sig), trait_item.span),
@@ -270,7 +272,7 @@ fn check_trait_item(tcx: TyCtxt<'_>, trait_item: &hir::TraitItem<'_>) {
         _ => (None, trait_item.span),
     };
     check_object_unsafe_self_trait_by_name(tcx, trait_item);
-    check_associated_item(tcx, trait_item.def_id, span, method_sig);
+    check_associated_item(tcx, def_id, span, method_sig);
 
     let encl_trait_def_id = tcx.local_parent(def_id);
     let encl_trait = tcx.hir().expect_item(encl_trait_def_id);
@@ -391,7 +393,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe
                             // We also assume that all of the function signature's parameter types
                             // are well formed.
                             &sig.inputs().iter().copied().collect(),
-                            gat_def_id,
+                            gat_def_id.def_id,
                             gat_generics,
                         )
                     }
@@ -414,7 +416,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe
                                 .copied()
                                 .collect::<Vec<_>>(),
                             &FxHashSet::default(),
-                            gat_def_id,
+                            gat_def_id.def_id,
                             gat_generics,
                         )
                     }
@@ -454,7 +456,7 @@ fn check_gat_where_clauses(tcx: TyCtxt<'_>, associated_items: &[hir::TraitItemRe
     }
 
     for (gat_def_id, required_bounds) in required_bounds_by_item {
-        let gat_item_hir = tcx.hir().expect_trait_item(gat_def_id);
+        let gat_item_hir = tcx.hir().expect_trait_item(gat_def_id.def_id);
         debug!(?required_bounds);
         let param_env = tcx.param_env(gat_def_id);
         let gat_hir = gat_item_hir.hir_id();
@@ -662,7 +664,7 @@ fn ty_known_to_outlive<'tcx>(
     resolve_regions_with_wf_tys(tcx, id, param_env, &wf_tys, |infcx, region_bound_pairs| {
         let origin = infer::RelateParamBound(DUMMY_SP, ty, None);
         let outlives = &mut TypeOutlives::new(infcx, tcx, region_bound_pairs, None, param_env);
-        outlives.type_must_outlive(origin, ty, region);
+        outlives.type_must_outlive(origin, ty, region, ConstraintCategory::BoringNoLocation);
     })
 }
 
@@ -680,7 +682,12 @@ fn region_known_to_outlive<'tcx>(
         use rustc_infer::infer::outlives::obligations::TypeOutlivesDelegate;
         let origin = infer::RelateRegionParamBound(DUMMY_SP);
         // `region_a: region_b` -> `region_b <= region_a`
-        infcx.push_sub_region_constraint(origin, region_b, region_a);
+        infcx.push_sub_region_constraint(
+            origin,
+            region_b,
+            region_a,
+            ConstraintCategory::BoringNoLocation,
+        );
     })
 }
 
@@ -768,7 +775,7 @@ impl<'tcx> TypeVisitor<'tcx> for GATSubstCollector<'tcx> {
 fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool {
     match ty.kind {
         hir::TyKind::TraitObject([trait_ref], ..) => match trait_ref.trait_ref.path.segments {
-            [s] => s.res.and_then(|r| r.opt_def_id()) == Some(trait_def_id.to_def_id()),
+            [s] => s.res.opt_def_id() == Some(trait_def_id.to_def_id()),
             _ => false,
         },
         _ => false,
@@ -779,7 +786,7 @@ fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool {
 /// When this is done, suggest using `Self` instead.
 fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem<'_>) {
     let (trait_name, trait_def_id) =
-        match tcx.hir().get_by_def_id(tcx.hir().get_parent_item(item.hir_id())) {
+        match tcx.hir().get_by_def_id(tcx.hir().get_parent_item(item.hir_id()).def_id) {
             hir::Node::Item(item) => match item.kind {
                 hir::ItemKind::Trait(..) => (item.ident, item.def_id),
                 _ => return,
@@ -789,18 +796,18 @@ fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem
     let mut trait_should_be_self = vec![];
     match &item.kind {
         hir::TraitItemKind::Const(ty, _) | hir::TraitItemKind::Type(_, Some(ty))
-            if could_be_self(trait_def_id, ty) =>
+            if could_be_self(trait_def_id.def_id, ty) =>
         {
             trait_should_be_self.push(ty.span)
         }
         hir::TraitItemKind::Fn(sig, _) => {
             for ty in sig.decl.inputs {
-                if could_be_self(trait_def_id, ty) {
+                if could_be_self(trait_def_id.def_id, ty) {
                     trait_should_be_self.push(ty.span);
                 }
             }
             match sig.decl.output {
-                hir::FnRetTy::Return(ty) if could_be_self(trait_def_id, ty) => {
+                hir::FnRetTy::Return(ty) if could_be_self(trait_def_id.def_id, ty) => {
                     trait_should_be_self.push(ty.span);
                 }
                 _ => {}
@@ -829,8 +836,6 @@ fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem
 }
 
 fn check_impl_item(tcx: TyCtxt<'_>, impl_item: &hir::ImplItem<'_>) {
-    let def_id = impl_item.def_id;
-
     let (method_sig, span) = match impl_item.kind {
         hir::ImplItemKind::Fn(ref sig, _) => (Some(sig), impl_item.span),
         // Constrain binding and overflow error spans to `<Ty>` in `type foo = <Ty>`.
@@ -838,7 +843,7 @@ fn check_impl_item(tcx: TyCtxt<'_>, impl_item: &hir::ImplItem<'_>) {
         _ => (None, impl_item.span),
     };
 
-    check_associated_item(tcx, def_id, span, method_sig);
+    check_associated_item(tcx, impl_item.def_id.def_id, span, method_sig);
 }
 
 fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) {
@@ -972,7 +977,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) {
     }
 }
 
-#[tracing::instrument(level = "debug", skip(tcx, span, sig_if_method))]
+#[instrument(level = "debug", skip(tcx, span, sig_if_method))]
 fn check_associated_item(
     tcx: TyCtxt<'_>,
     item_id: LocalDefId,
@@ -1038,7 +1043,7 @@ fn check_type_defn<'tcx, F>(
 ) where
     F: FnMut(&WfCheckingCtxt<'_, 'tcx>) -> Vec<AdtVariant<'tcx>>,
 {
-    enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| {
+    enter_wf_checking_ctxt(tcx, item.span, item.def_id.def_id, |wfcx| {
         let variants = lookup_fields(wfcx);
         let packed = tcx.adt_def(item.def_id).repr().packed();
 
@@ -1106,16 +1111,18 @@ fn check_type_defn<'tcx, F>(
                 wfcx.register_obligation(traits::Obligation::new(
                     cause,
                     wfcx.param_env,
-                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ty::Unevaluated::new(
-                        ty::WithOptConstParam::unknown(discr_def_id.to_def_id()),
-                        discr_substs,
-                    )))
+                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(
+                        ty::UnevaluatedConst::new(
+                            ty::WithOptConstParam::unknown(discr_def_id.to_def_id()),
+                            discr_substs,
+                        ),
+                    ))
                     .to_predicate(tcx),
                 ));
             }
         }
 
-        check_where_clauses(wfcx, item.span, item.def_id);
+        check_where_clauses(wfcx, item.span, item.def_id.def_id);
     });
 }
 
@@ -1123,11 +1130,12 @@ fn check_type_defn<'tcx, F>(
 fn check_trait(tcx: TyCtxt<'_>, item: &hir::Item<'_>) {
     debug!(?item.def_id);
 
-    let trait_def = tcx.trait_def(item.def_id);
+    let def_id = item.def_id.def_id;
+    let trait_def = tcx.trait_def(def_id);
     if trait_def.is_marker
         || matches!(trait_def.specialization_kind, TraitSpecializationKind::Marker)
     {
-        for associated_def_id in &*tcx.associated_item_def_ids(item.def_id) {
+        for associated_def_id in &*tcx.associated_item_def_ids(def_id) {
             struct_span_err!(
                 tcx.sess,
                 tcx.def_span(*associated_def_id),
@@ -1138,8 +1146,8 @@ fn check_trait(tcx: TyCtxt<'_>, item: &hir::Item<'_>) {
         }
     }
 
-    enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| {
-        check_where_clauses(wfcx, item.span, item.def_id)
+    enter_wf_checking_ctxt(tcx, item.span, def_id, |wfcx| {
+        check_where_clauses(wfcx, item.span, def_id)
     });
 
     // Only check traits, don't check trait aliases
@@ -1225,7 +1233,7 @@ fn check_item_type(tcx: TyCtxt<'_>, item_id: LocalDefId, ty_span: Span, allow_fo
     });
 }
 
-#[tracing::instrument(level = "debug", skip(tcx, ast_self_ty, ast_trait_ref))]
+#[instrument(level = "debug", skip(tcx, ast_self_ty, ast_trait_ref))]
 fn check_impl<'tcx>(
     tcx: TyCtxt<'tcx>,
     item: &'tcx hir::Item<'tcx>,
@@ -1233,7 +1241,7 @@ fn check_impl<'tcx>(
     ast_trait_ref: &Option<hir::TraitRef<'_>>,
     constness: hir::Constness,
 ) {
-    enter_wf_checking_ctxt(tcx, item.span, item.def_id, |wfcx| {
+    enter_wf_checking_ctxt(tcx, item.span, item.def_id.def_id, |wfcx| {
         match *ast_trait_ref {
             Some(ref ast_trait_ref) => {
                 // `#[rustc_reservation_impl]` impls are not real impls and
@@ -1264,18 +1272,18 @@ fn check_impl<'tcx>(
                 let self_ty = tcx.type_of(item.def_id);
                 let self_ty = wfcx.normalize(
                     item.span,
-                    Some(WellFormedLoc::Ty(item.hir_id().expect_owner())),
+                    Some(WellFormedLoc::Ty(item.hir_id().expect_owner().def_id)),
                     self_ty,
                 );
                 wfcx.register_wf_obligation(
                     ast_self_ty.span,
-                    Some(WellFormedLoc::Ty(item.hir_id().expect_owner())),
+                    Some(WellFormedLoc::Ty(item.hir_id().expect_owner().def_id)),
                     self_ty.into(),
                 );
             }
         }
 
-        check_where_clauses(wfcx, item.span, item.def_id);
+        check_where_clauses(wfcx, item.span, item.def_id.def_id);
     });
 }
 
@@ -1472,7 +1480,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
     wfcx.register_obligations(obligations);
 }
 
-#[tracing::instrument(level = "debug", skip(wfcx, span, hir_decl))]
+#[instrument(level = "debug", skip(wfcx, span, hir_decl))]
 fn check_fn_or_method<'tcx>(
     wfcx: &WfCheckingCtxt<'_, 'tcx>,
     span: Span,
@@ -1530,13 +1538,56 @@ fn check_fn_or_method<'tcx>(
     );
 
     check_where_clauses(wfcx, span, def_id);
+
+    check_return_position_impl_trait_in_trait_bounds(
+        tcx,
+        wfcx,
+        def_id,
+        sig.output(),
+        hir_decl.output.span(),
+    );
+}
+
+/// Basically `check_associated_type_bounds`, but separated for now and should be
+/// deduplicated when RPITITs get lowered into real associated items.
+fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    wfcx: &WfCheckingCtxt<'_, 'tcx>,
+    fn_def_id: LocalDefId,
+    fn_output: Ty<'tcx>,
+    span: Span,
+) {
+    if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id())
+        && assoc_item.container == ty::AssocItemContainer::TraitContainer
+    {
+        for arg in fn_output.walk() {
+            if let ty::GenericArgKind::Type(ty) = arg.unpack()
+                && let ty::Projection(proj) = ty.kind()
+                && tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
+                && tcx.impl_trait_in_trait_parent(proj.item_def_id) == fn_def_id.to_def_id()
+            {
+                let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id);
+                let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| {
+                    let normalized_bound = wfcx.normalize(span, None, bound);
+                    traits::wf::predicate_obligations(
+                        wfcx.infcx,
+                        wfcx.param_env,
+                        wfcx.body_id,
+                        normalized_bound,
+                        bound_span,
+                    )
+                });
+                wfcx.register_obligations(wf_obligations);
+            }
+        }
+    }
 }
 
 const HELP_FOR_SELF_TYPE: &str = "consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, \
      `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one \
      of the previous types except `Self`)";
 
-#[tracing::instrument(level = "debug", skip(wfcx))]
+#[instrument(level = "debug", skip(wfcx))]
 fn check_method_receiver<'tcx>(
     wfcx: &WfCheckingCtxt<'_, 'tcx>,
     fn_sig: &hir::FnSig<'_>,
@@ -1816,6 +1867,7 @@ fn report_bivariance(
 impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
     /// Feature gates RFC 2056 -- trivial bounds, checking for global bounds that
     /// aren't true.
+    #[instrument(level = "debug", skip(self))]
     fn check_false_global_bounds(&mut self) {
         let tcx = self.ocx.infcx.tcx;
         let mut span = self.span;
diff --git a/compiler/rustc_typeck/src/check/writeback.rs b/compiler/rustc_typeck/src/check/writeback.rs
index ba687bc4da4c..680dbf7037fa 100644
--- a/compiler/rustc_typeck/src/check/writeback.rs
+++ b/compiler/rustc_typeck/src/check/writeback.rs
@@ -501,7 +501,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
 
         if !errors_buffer.is_empty() {
             errors_buffer.sort_by_key(|diag| diag.span.primary_span());
-            for mut diag in errors_buffer.drain(..) {
+            for mut diag in errors_buffer {
                 self.tcx().sess.diagnostic().emit_diagnostic(&mut diag);
             }
         }
@@ -717,27 +717,13 @@ impl<'cx, 'tcx> Resolver<'cx, 'tcx> {
         Resolver { tcx: fcx.tcx, infcx: fcx, span, body, replaced_with_error: false }
     }
 
-    fn report_type_error(&self, t: Ty<'tcx>) {
+    fn report_error(&self, p: impl Into<ty::GenericArg<'tcx>>) {
         if !self.tcx.sess.has_errors().is_some() {
             self.infcx
                 .emit_inference_failure_err(
                     Some(self.body.id()),
                     self.span.to_span(self.tcx),
-                    t.into(),
-                    E0282,
-                    false,
-                )
-                .emit();
-        }
-    }
-
-    fn report_const_error(&self, c: ty::Const<'tcx>) {
-        if self.tcx.sess.has_errors().is_none() {
-            self.infcx
-                .emit_inference_failure_err(
-                    Some(self.body.id()),
-                    self.span.to_span(self.tcx),
-                    c.into(),
+                    p.into(),
                     E0282,
                     false,
                 )
@@ -782,7 +768,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> {
             }
             Err(_) => {
                 debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t);
-                self.report_type_error(t);
+                self.report_error(t);
                 self.replaced_with_error = true;
                 self.tcx().ty_error()
             }
@@ -799,7 +785,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> {
             Ok(ct) => self.tcx.erase_regions(ct),
             Err(_) => {
                 debug!("Resolver::fold_const: input const `{:?}` not fully resolvable", ct);
-                self.report_const_error(ct);
+                self.report_error(ct);
                 self.replaced_with_error = true;
                 self.tcx().const_error(ct.ty())
             }
diff --git a/compiler/rustc_typeck/src/coherence/builtin.rs b/compiler/rustc_typeck/src/coherence/builtin.rs
index d08c0d4dbb72..d4eb826f0b4d 100644
--- a/compiler/rustc_typeck/src/coherence/builtin.rs
+++ b/compiler/rustc_typeck/src/coherence/builtin.rs
@@ -70,23 +70,21 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
     let self_type = tcx.type_of(impl_did);
     debug!("visit_implementation_of_copy: self_type={:?} (bound)", self_type);
 
-    let span = tcx.hir().span(impl_hir_id);
     let param_env = tcx.param_env(impl_did);
     assert!(!self_type.has_escaping_bound_vars());
 
     debug!("visit_implementation_of_copy: self_type={:?} (free)", self_type);
 
+    let span = match tcx.hir().expect_item(impl_did).kind {
+        ItemKind::Impl(hir::Impl { polarity: hir::ImplPolarity::Negative(_), .. }) => return,
+        ItemKind::Impl(impl_) => impl_.self_ty.span,
+        _ => bug!("expected Copy impl item"),
+    };
+
     let cause = traits::ObligationCause::misc(span, impl_hir_id);
     match can_type_implement_copy(tcx, param_env, self_type, cause) {
         Ok(()) => {}
         Err(CopyImplementationError::InfrigingFields(fields)) => {
-            let item = tcx.hir().expect_item(impl_did);
-            let span = if let ItemKind::Impl(hir::Impl { of_trait: Some(ref tr), .. }) = item.kind {
-                tr.path.span
-            } else {
-                span
-            };
-
             let mut err = struct_span_err!(
                 tcx.sess,
                 span,
@@ -166,10 +164,6 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
             err.emit();
         }
         Err(CopyImplementationError::NotAnAdt) => {
-            let item = tcx.hir().expect_item(impl_did);
-            let span =
-                if let ItemKind::Impl(ref impl_) = item.kind { impl_.self_ty.span } else { span };
-
             tcx.sess.emit_err(CopyImplOnNonAdt { span });
         }
         Err(CopyImplementationError::HasDestructor) => {
diff --git a/compiler/rustc_typeck/src/coherence/inherent_impls.rs b/compiler/rustc_typeck/src/coherence/inherent_impls.rs
index 52aad636fd88..308ad5d5fc2c 100644
--- a/compiler/rustc_typeck/src/coherence/inherent_impls.rs
+++ b/compiler/rustc_typeck/src/coherence/inherent_impls.rs
@@ -105,7 +105,7 @@ impl<'tcx> InherentCollect<'tcx> {
             }
 
             if let Some(simp) = simplify_type(self.tcx, self_ty, TreatParams::AsInfer) {
-                self.impls_map.incoherent_impls.entry(simp).or_default().push(impl_def_id);
+                self.impls_map.incoherent_impls.entry(simp).or_default().push(impl_def_id.def_id);
             } else {
                 bug!("unexpected self type: {:?}", self_ty);
             }
@@ -220,7 +220,9 @@ impl<'tcx> InherentCollect<'tcx> {
             | ty::Ref(..)
             | ty::Never
             | ty::FnPtr(_)
-            | ty::Tuple(..) => self.check_primitive_impl(item.def_id, self_ty, items, ty.span),
+            | ty::Tuple(..) => {
+                self.check_primitive_impl(item.def_id.def_id, self_ty, items, ty.span)
+            }
             ty::Projection(..) | ty::Opaque(..) | ty::Param(_) => {
                 let mut err = struct_span_err!(
                     self.tcx.sess,
diff --git a/compiler/rustc_typeck/src/coherence/orphan.rs b/compiler/rustc_typeck/src/coherence/orphan.rs
index 1608550aa6ae..7d15e5a7f3c2 100644
--- a/compiler/rustc_typeck/src/coherence/orphan.rs
+++ b/compiler/rustc_typeck/src/coherence/orphan.rs
@@ -5,7 +5,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_errors::{Diagnostic, ErrorGuaranteed};
 use rustc_hir as hir;
-use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::util::IgnoreRegions;
@@ -43,7 +42,7 @@ fn do_orphan_check_impl<'tcx>(
 ) -> Result<(), ErrorGuaranteed> {
     let trait_def_id = trait_ref.def_id;
 
-    let item = tcx.hir().item(hir::ItemId { def_id });
+    let item = tcx.hir().expect_item(def_id);
     let hir::ItemKind::Impl(ref impl_) = item.kind else {
         bug!("{:?} is not an impl: {:?}", def_id, item);
     };
@@ -229,12 +228,8 @@ fn emit_orphan_check_error<'tcx>(
                 "only traits defined in the current crate {msg}"
             );
             err.span_label(sp, "impl doesn't use only types from inside the current crate");
-            for (ty, is_target_ty) in &tys {
-                let mut ty = *ty;
-                tcx.infer_ctxt().enter(|infcx| {
-                    // Remove the lifetimes unnecessary for this error.
-                    ty = infcx.freshen(ty);
-                });
+            for &(mut ty, is_target_ty) in &tys {
+                ty = tcx.erase_regions(ty);
                 ty = match ty.kind() {
                     // Remove the type arguments from the output, as they are not relevant.
                     // You can think of this as the reverse of `resolve_vars_if_possible`.
@@ -264,7 +259,7 @@ fn emit_orphan_check_error<'tcx>(
                 };
 
                 let msg = format!("{} is not defined in the current crate{}", ty, postfix);
-                if *is_target_ty {
+                if is_target_ty {
                     // Point at `D<A>` in `impl<A, B> for C<B> in D<A>`
                     err.span_label(self_ty_span, &msg);
                 } else {
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index 6236ad370df6..e7deae2b557c 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -25,10 +25,10 @@ use rustc_ast::{MetaItemKind, NestedMetaItem};
 use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
-use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
+use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::weak_lang_items;
 use rustc_hir::{GenericParamKind, HirId, Node};
@@ -430,7 +430,6 @@ impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
         if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
             let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
                 self,
-                self.tcx,
                 span,
                 item_def_id,
                 item_segment,
@@ -449,8 +448,10 @@ impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
 
             match self.node() {
                 hir::Node::Field(_) | hir::Node::Ctor(_) | hir::Node::Variant(_) => {
-                    let item =
-                        self.tcx.hir().expect_item(self.tcx.hir().get_parent_item(self.hir_id()));
+                    let item = self
+                        .tcx
+                        .hir()
+                        .expect_item(self.tcx.hir().get_parent_item(self.hir_id()).def_id);
                     match &item.kind {
                         hir::ItemKind::Enum(_, generics)
                         | hir::ItemKind::Struct(_, generics)
@@ -573,6 +574,7 @@ fn get_new_lifetime_name<'tcx>(
 
 /// Returns the predicates defined on `item_def_id` of the form
 /// `X: Foo` where `X` is the type parameter `def_id`.
+#[instrument(level = "trace", skip(tcx))]
 fn type_param_predicates(
     tcx: TyCtxt<'_>,
     (item_def_id, def_id, assoc_name): (DefId, LocalDefId, Ident),
@@ -679,7 +681,7 @@ impl<'tcx> ItemCtxt<'tcx> {
         assoc_name: Option<Ident>,
     ) -> Vec<(ty::Predicate<'tcx>, Span)> {
         let param_def_id = self.tcx.hir().local_def_id(param_id).to_def_id();
-        debug!(?param_def_id);
+        trace!(?param_def_id);
         ast_generics
             .predicates
             .iter()
@@ -708,9 +710,8 @@ impl<'tcx> ItemCtxt<'tcx> {
             .collect()
     }
 
+    #[instrument(level = "trace", skip(self))]
     fn bound_defines_assoc_item(&self, b: &hir::GenericBound<'_>, assoc_name: Ident) -> bool {
-        debug!("bound_defines_assoc_item(b={:?}, assoc_name={:?})", b, assoc_name);
-
         match b {
             hir::GenericBound::Trait(poly_trait_ref, _) => {
                 let trait_ref = &poly_trait_ref.trait_ref;
@@ -728,7 +729,7 @@ impl<'tcx> ItemCtxt<'tcx> {
 fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
     let it = tcx.hir().item(item_id);
     debug!("convert: item {} with id {}", it.ident, it.hir_id());
-    let def_id = item_id.def_id;
+    let def_id = item_id.def_id.def_id;
 
     match it.kind {
         // These don't define types.
@@ -840,29 +841,32 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
 
 fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
     let trait_item = tcx.hir().trait_item(trait_item_id);
-    tcx.ensure().generics_of(trait_item_id.def_id);
+    let def_id = trait_item_id.def_id;
+    tcx.ensure().generics_of(def_id);
 
     match trait_item.kind {
         hir::TraitItemKind::Fn(..) => {
-            tcx.ensure().type_of(trait_item_id.def_id);
-            tcx.ensure().fn_sig(trait_item_id.def_id);
+            tcx.ensure().type_of(def_id);
+            tcx.ensure().fn_sig(def_id);
         }
 
         hir::TraitItemKind::Const(.., Some(_)) => {
-            tcx.ensure().type_of(trait_item_id.def_id);
+            tcx.ensure().type_of(def_id);
         }
 
-        hir::TraitItemKind::Const(..) => {
-            tcx.ensure().type_of(trait_item_id.def_id);
+        hir::TraitItemKind::Const(hir_ty, _) => {
+            tcx.ensure().type_of(def_id);
             // Account for `const C: _;`.
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_trait_item(trait_item);
-            placeholder_type_error(tcx, None, visitor.0, false, None, "constant");
+            if !tcx.sess.diagnostic().has_stashed_diagnostic(hir_ty.span, StashKey::ItemNoType) {
+                placeholder_type_error(tcx, None, visitor.0, false, None, "constant");
+            }
         }
 
         hir::TraitItemKind::Type(_, Some(_)) => {
-            tcx.ensure().item_bounds(trait_item_id.def_id);
-            tcx.ensure().type_of(trait_item_id.def_id);
+            tcx.ensure().item_bounds(def_id);
+            tcx.ensure().type_of(def_id);
             // Account for `type T = _;`.
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_trait_item(trait_item);
@@ -870,7 +874,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
         }
 
         hir::TraitItemKind::Type(_, None) => {
-            tcx.ensure().item_bounds(trait_item_id.def_id);
+            tcx.ensure().item_bounds(def_id);
             // #74612: Visit and try to find bad placeholders
             // even if there is no concrete type.
             let mut visitor = HirPlaceholderCollector::default();
@@ -880,7 +884,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
         }
     };
 
-    tcx.ensure().predicates_of(trait_item_id.def_id);
+    tcx.ensure().predicates_of(def_id);
 }
 
 fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
@@ -1346,16 +1350,12 @@ fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<S
             }
         }
 
-        fn visit_poly_trait_ref(
-            &mut self,
-            tr: &'tcx hir::PolyTraitRef<'tcx>,
-            m: hir::TraitBoundModifier,
-        ) {
+        fn visit_poly_trait_ref(&mut self, tr: &'tcx hir::PolyTraitRef<'tcx>) {
             if self.has_late_bound_regions.is_some() {
                 return;
             }
             self.outer_index.shift_in(1);
-            intravisit::walk_poly_trait_ref(self, tr, m);
+            intravisit::walk_poly_trait_ref(self, tr);
             self.outer_index.shift_out(1);
         }
 
@@ -1585,11 +1585,19 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
             ItemKind::OpaqueTy(hir::OpaqueTy {
                 origin:
                     hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
+                in_trait,
                 ..
-            }) => Some(fn_def_id.to_def_id()),
+            }) => {
+                if in_trait {
+                    assert!(matches!(tcx.def_kind(fn_def_id), DefKind::AssocFn))
+                } else {
+                    assert!(matches!(tcx.def_kind(fn_def_id), DefKind::AssocFn | DefKind::Fn))
+                }
+                Some(fn_def_id.to_def_id())
+            }
             ItemKind::OpaqueTy(hir::OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
                 let parent_id = tcx.hir().get_parent_item(hir_id);
-                assert_ne!(parent_id, CRATE_DEF_ID);
+                assert_ne!(parent_id, hir::CRATE_OWNER_ID);
                 debug!("generics_of: parent of opaque ty {:?} is {:?}", def_id, parent_id);
                 // Opaque types are always nested within another item, and
                 // inherit the generics of the item.
@@ -1600,6 +1608,13 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
         _ => None,
     };
 
+    enum Defaults {
+        Allowed,
+        // See #36887
+        FutureCompatDisallowed,
+        Deny,
+    }
+
     let no_generics = hir::Generics::empty();
     let ast_generics = node.generics().unwrap_or(&no_generics);
     let (opt_self, allow_defaults) = match node {
@@ -1621,17 +1636,26 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
                         },
                     });
 
-                    (opt_self, true)
+                    (opt_self, Defaults::Allowed)
                 }
                 ItemKind::TyAlias(..)
                 | ItemKind::Enum(..)
                 | ItemKind::Struct(..)
                 | ItemKind::OpaqueTy(..)
-                | ItemKind::Union(..) => (None, true),
-                _ => (None, false),
+                | ItemKind::Union(..) => (None, Defaults::Allowed),
+                _ => (None, Defaults::FutureCompatDisallowed),
             }
         }
-        _ => (None, false),
+
+        // GATs
+        Node::TraitItem(item) if matches!(item.kind, TraitItemKind::Type(..)) => {
+            (None, Defaults::Deny)
+        }
+        Node::ImplItem(item) if matches!(item.kind, ImplItemKind::TyAlias(..)) => {
+            (None, Defaults::Deny)
+        }
+
+        _ => (None, Defaults::FutureCompatDisallowed),
     };
 
     let has_self = opt_self.is_some();
@@ -1664,23 +1688,30 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
     let type_start = own_start - has_self as u32 + params.len() as u32;
     let mut i = 0;
 
+    const TYPE_DEFAULT_NOT_ALLOWED: &'static str = "defaults for type parameters are only allowed in \
+    `struct`, `enum`, `type`, or `trait` definitions";
+
     params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
         GenericParamKind::Lifetime { .. } => None,
         GenericParamKind::Type { ref default, synthetic, .. } => {
-            if !allow_defaults && default.is_some() {
-                if !tcx.features().default_type_parameter_fallback {
-                    tcx.struct_span_lint_hir(
-                        lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
-                        param.hir_id,
-                        param.span,
-                        |lint| {
-                            lint.build(
-                                "defaults for type parameters are only allowed in \
-                                 `struct`, `enum`, `type`, or `trait` definitions",
-                            )
-                            .emit();
-                        },
-                    );
+            if default.is_some() {
+                match allow_defaults {
+                    Defaults::Allowed => {}
+                    Defaults::FutureCompatDisallowed
+                        if tcx.features().default_type_parameter_fallback => {}
+                    Defaults::FutureCompatDisallowed => {
+                        tcx.struct_span_lint_hir(
+                            lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
+                            param.hir_id,
+                            param.span,
+                            |lint| {
+                                lint.build(TYPE_DEFAULT_NOT_ALLOWED).emit();
+                            },
+                        );
+                    }
+                    Defaults::Deny => {
+                        tcx.sess.span_err(param.span, TYPE_DEFAULT_NOT_ALLOWED);
+                    }
                 }
             }
 
@@ -1697,7 +1728,7 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
             Some(param_def)
         }
         GenericParamKind::Const { default, .. } => {
-            if !allow_defaults && default.is_some() {
+            if !matches!(allow_defaults, Defaults::Allowed) && default.is_some() {
                 tcx.sess.span_err(
                     param.span,
                     "defaults for const parameters are only allowed in \
@@ -1787,7 +1818,7 @@ fn is_suggestable_infer_ty(ty: &hir::Ty<'_>) -> bool {
         }
         Tup(tys) => tys.iter().any(is_suggestable_infer_ty),
         Ptr(mut_ty) | Rptr(_, mut_ty) => is_suggestable_infer_ty(mut_ty.ty),
-        OpaqueDef(_, generic_args) => are_suggestable_generic_args(generic_args),
+        OpaqueDef(_, generic_args, _) => are_suggestable_generic_args(generic_args),
         Path(hir::QPath::TypeRelative(ty, segment)) => {
             is_suggestable_infer_ty(ty) || are_suggestable_generic_args(segment.args().args)
         }
@@ -1808,6 +1839,7 @@ pub fn get_infer_ret_ty<'hir>(output: &'hir hir::FnRetTy<'hir>) -> Option<&'hir
     None
 }
 
+#[instrument(level = "debug", skip(tcx))]
 fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
     use rustc_hir::Node::*;
     use rustc_hir::*;
@@ -2038,8 +2070,8 @@ fn early_bound_lifetimes_from_generics<'a, 'tcx: 'a>(
 /// Returns a list of type predicates for the definition with ID `def_id`, including inferred
 /// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
 /// inferred constraints concerning which regions outlive other regions.
+#[instrument(level = "debug", skip(tcx))]
 fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
-    debug!("predicates_defined_on({:?})", def_id);
     let mut result = tcx.explicit_predicates_of(def_id);
     debug!("predicates_defined_on: explicit_predicates_of({:?}) = {:?}", def_id, result,);
     let inferred_outlives = tcx.inferred_outlives_of(def_id);
@@ -2105,11 +2137,10 @@ fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
 
 /// Returns a list of user-specified type predicates for the definition with ID `def_id`.
 /// N.B., this does not include any implied/inferred constraints.
+#[instrument(level = "trace", skip(tcx), ret)]
 fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicates<'_> {
     use rustc_hir::*;
 
-    debug!("explicit_predicates_of(def_id={:?})", def_id);
-
     let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
     let node = tcx.hir().get(hir_id);
 
@@ -2224,6 +2255,9 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
         + has_own_self as u32
         + early_bound_lifetimes_from_generics(tcx, ast_generics).count() as u32;
 
+    trace!(?predicates);
+    trace!(?ast_generics);
+
     // Collect the predicates that were written inline by the user on each
     // type parameter (e.g., `<T: Foo>`).
     for param in ast_generics.params {
@@ -2244,7 +2278,9 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
                     Some((param.hir_id, ast_generics.predicates)),
                     param.span,
                 );
+                trace!(?bounds);
                 predicates.extend(bounds.predicates(tcx, param_ty));
+                trace!(?predicates);
             }
             GenericParamKind::Const { .. } => {
                 // Bounds on const parameters are currently not possible.
@@ -2253,6 +2289,7 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
         }
     }
 
+    trace!(?predicates);
     // Add in the bounds that appear in the where-clause.
     for predicate in ast_generics.predicates {
         match predicate {
@@ -2338,12 +2375,10 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
         );
     }
 
-    let result = ty::GenericPredicates {
+    ty::GenericPredicates {
         parent: generics.parent,
         predicates: tcx.arena.alloc_from_iter(predicates),
-    };
-    debug!("explicit_predicates_of(def_id={:?}) = {:?}", def_id, result);
-    result
+    }
 }
 
 fn const_evaluatable_predicates_of<'tcx>(
@@ -2360,10 +2395,9 @@ fn const_evaluatable_predicates_of<'tcx>(
             let def_id = self.tcx.hir().local_def_id(c.hir_id);
             let ct = ty::Const::from_anon_const(self.tcx, def_id);
             if let ty::ConstKind::Unevaluated(uv) = ct.kind() {
-                assert_eq!(uv.promoted, None);
                 let span = self.tcx.hir().span(c.hir_id);
                 self.preds.insert((
-                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv.shrink()))
+                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv))
                         .to_predicate(self.tcx),
                     span,
                 ));
@@ -3121,6 +3155,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
                         E0535,
                         "invalid argument"
                     )
+                    .help("valid inline arguments are `always` and `never`")
                     .emit();
 
                     InlineAttr::None
@@ -3276,6 +3311,15 @@ fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
 
 fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<u16> {
     use rustc_ast::{Lit, LitIntType, LitKind};
+    if !tcx.features().raw_dylib && tcx.sess.target.arch == "x86" {
+        feature_err(
+            &tcx.sess.parse_sess,
+            sym::raw_dylib,
+            attr.span,
+            "`#[link_ordinal]` is unstable on x86",
+        )
+        .emit();
+    }
     let meta_item_list = attr.meta_item_list();
     let meta_item_list: Option<&[ast::NestedMetaItem]> = meta_item_list.as_ref().map(Vec::as_ref);
     let sole_meta_list = match meta_item_list {
@@ -3344,7 +3388,7 @@ fn check_target_feature_trait_unsafe(tcx: TyCtxt<'_>, id: LocalDefId, attr_span:
     let node = tcx.hir().get(hir_id);
     if let Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) = node {
         let parent_id = tcx.hir().get_parent_item(hir_id);
-        let parent_item = tcx.hir().expect_item(parent_id);
+        let parent_item = tcx.hir().expect_item(parent_id.def_id);
         if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = parent_item.kind {
             tcx.sess
                 .struct_span_err(
diff --git a/compiler/rustc_typeck/src/collect/item_bounds.rs b/compiler/rustc_typeck/src/collect/item_bounds.rs
index 0d2b75d3328f..0d34a8bfee33 100644
--- a/compiler/rustc_typeck/src/collect/item_bounds.rs
+++ b/compiler/rustc_typeck/src/collect/item_bounds.rs
@@ -53,20 +53,28 @@ fn associated_type_bounds<'tcx>(
 /// impl trait it isn't possible to write a suitable predicate on the
 /// containing function and for type-alias impl trait we don't have a backwards
 /// compatibility issue.
+#[instrument(level = "trace", skip(tcx), ret)]
 fn opaque_type_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
     opaque_def_id: DefId,
     ast_bounds: &'tcx [hir::GenericBound<'tcx>],
     span: Span,
+    in_trait: bool,
 ) -> &'tcx [(ty::Predicate<'tcx>, Span)] {
     ty::print::with_no_queries!({
-        let item_ty =
-            tcx.mk_opaque(opaque_def_id, InternalSubsts::identity_for_item(tcx, opaque_def_id));
+        let substs = InternalSubsts::identity_for_item(tcx, opaque_def_id);
+        let item_ty = if in_trait {
+            tcx.mk_projection(opaque_def_id, substs)
+        } else {
+            tcx.mk_opaque(opaque_def_id, substs)
+        };
 
         let icx = ItemCtxt::new(tcx, opaque_def_id);
         let mut bounds = <dyn AstConv<'_>>::compute_bounds(&icx, item_ty, ast_bounds);
         // Opaque types are implicitly sized unless a `?Sized` bound is found
         <dyn AstConv<'_>>::add_implicitly_sized(&icx, &mut bounds, ast_bounds, None, span);
+        debug!(?bounds);
+
         tcx.arena.alloc_from_iter(bounds.predicates(tcx, item_ty))
     })
 }
@@ -83,10 +91,10 @@ pub(super) fn explicit_item_bounds(
             ..
         }) => associated_type_bounds(tcx, def_id, bounds, *span),
         hir::Node::Item(hir::Item {
-            kind: hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds, .. }),
+            kind: hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds, in_trait, .. }),
             span,
             ..
-        }) => opaque_type_bounds(tcx, def_id, bounds, *span),
+        }) => opaque_type_bounds(tcx, def_id, bounds, *span, *in_trait),
         _ => bug!("item_bounds called on {:?}", def_id),
     }
 }
diff --git a/compiler/rustc_typeck/src/collect/type_of.rs b/compiler/rustc_typeck/src/collect/type_of.rs
index f1dbe64f13ab..24fb0b1fd26b 100644
--- a/compiler/rustc_typeck/src/collect/type_of.rs
+++ b/compiler/rustc_typeck/src/collect/type_of.rs
@@ -1,6 +1,5 @@
 use rustc_errors::{Applicability, StashKey};
 use rustc_hir as hir;
-use rustc_hir::def::Res;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit;
 use rustc_hir::intravisit::Visitor;
@@ -19,7 +18,6 @@ use crate::errors::UnconstrainedOpaqueType;
 /// Computes the relevant generic parameter for a potential generic const argument.
 ///
 /// This should be called using the query `tcx.opt_const_param_of`.
-#[instrument(level = "debug", skip(tcx))]
 pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<DefId> {
     use hir::*;
     let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
@@ -67,8 +65,8 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
             let ty = item_ctxt.ast_ty_to_ty(hir_ty);
 
             // Iterate through the generics of the projection to find the one that corresponds to
-            // the def_id that this query was called with. We filter to only const args here as a
-            // precaution for if it's ever allowed to elide lifetimes in GAT's. It currently isn't
+            // the def_id that this query was called with. We filter to only type and const args here
+            // as a precaution for if it's ever allowed to elide lifetimes in GAT's. It currently isn't
             // but it can't hurt to be safe ^^
             if let ty::Projection(projection) = ty.kind() {
                 let generics = tcx.generics_of(projection.item_def_id);
@@ -79,7 +77,7 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
                         args.args
                             .iter()
                             .filter(|arg| arg.is_ty_or_const())
-                            .position(|arg| arg.id() == hir_id)
+                            .position(|arg| arg.hir_id() == hir_id)
                     })
                     .unwrap_or_else(|| {
                         bug!("no arg matching AnonConst in segment");
@@ -112,7 +110,7 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
                     args.args
                         .iter()
                         .filter(|arg| arg.is_ty_or_const())
-                        .position(|arg| arg.id() == hir_id)
+                        .position(|arg| arg.hir_id() == hir_id)
                 })
                 .unwrap_or_else(|| {
                     bug!("no arg matching AnonConst in segment");
@@ -166,7 +164,7 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
                 args.args
                 .iter()
                 .filter(|arg| arg.is_ty_or_const())
-                .position(|arg| arg.id() == hir_id)
+                .position(|arg| arg.hir_id() == hir_id)
                 .map(|index| (index, seg)).or_else(|| args.bindings
                     .iter()
                     .filter_map(TypeBinding::opt_const)
@@ -180,15 +178,12 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
                 return None;
             };
 
-            // Try to use the segment resolution if it is valid, otherwise we
-            // default to the path resolution.
-            let res = segment.res.filter(|&r| r != Res::Err).unwrap_or(path.res);
-            let generics = match tcx.res_generics_def_id(res) {
+            let generics = match tcx.res_generics_def_id(segment.res) {
                 Some(def_id) => tcx.generics_of(def_id),
                 None => {
                     tcx.sess.delay_span_bug(
                         tcx.def_span(def_id),
-                        &format!("unexpected anon const res {:?} in path: {:?}", res, path),
+                        &format!("unexpected anon const res {:?} in path: {:?}", segment.res, path),
                     );
                     return None;
                 }
@@ -229,7 +224,7 @@ fn get_path_containing_arg_in_pat<'hir>(
             .iter()
             .filter_map(|seg| seg.args)
             .flat_map(|args| args.args)
-            .any(|arg| arg.id() == arg_id)
+            .any(|arg| arg.hir_id() == arg_id)
     };
     let mut arg_path = None;
     pat.walk(|pat| match pat.kind {
@@ -338,8 +333,12 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                     find_opaque_ty_constraints_for_tait(tcx, def_id)
                 }
                 // Opaque types desugared from `impl Trait`.
-                ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::FnReturn(owner) | hir::OpaqueTyOrigin::AsyncFn(owner), .. }) => {
-                    find_opaque_ty_constraints_for_rpit(tcx, def_id, owner)
+                ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::FnReturn(owner) | hir::OpaqueTyOrigin::AsyncFn(owner), in_trait, .. }) => {
+                    if in_trait {
+                        span_bug!(item.span, "impl-trait in trait has no default")
+                    } else {
+                        find_opaque_ty_constraints_for_rpit(tcx, def_id, owner)
+                    }
                 }
                 ItemKind::Trait(..)
                 | ItemKind::TraitAlias(..)
@@ -570,22 +569,22 @@ fn find_opaque_ty_constraints_for_tait(tcx: TyCtxt<'_>, def_id: LocalDefId) -> T
         fn visit_item(&mut self, it: &'tcx Item<'tcx>) {
             trace!(?it.def_id);
             // The opaque type itself or its children are not within its reveal scope.
-            if it.def_id != self.def_id {
-                self.check(it.def_id);
+            if it.def_id.def_id != self.def_id {
+                self.check(it.def_id.def_id);
                 intravisit::walk_item(self, it);
             }
         }
         fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) {
             trace!(?it.def_id);
             // The opaque type itself or its children are not within its reveal scope.
-            if it.def_id != self.def_id {
-                self.check(it.def_id);
+            if it.def_id.def_id != self.def_id {
+                self.check(it.def_id.def_id);
                 intravisit::walk_impl_item(self, it);
             }
         }
         fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) {
             trace!(?it.def_id);
-            self.check(it.def_id);
+            self.check(it.def_id.def_id);
             intravisit::walk_trait_item(self, it);
         }
     }
@@ -689,22 +688,22 @@ fn find_opaque_ty_constraints_for_rpit(
         fn visit_item(&mut self, it: &'tcx Item<'tcx>) {
             trace!(?it.def_id);
             // The opaque type itself or its children are not within its reveal scope.
-            if it.def_id != self.def_id {
-                self.check(it.def_id);
+            if it.def_id.def_id != self.def_id {
+                self.check(it.def_id.def_id);
                 intravisit::walk_item(self, it);
             }
         }
         fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) {
             trace!(?it.def_id);
             // The opaque type itself or its children are not within its reveal scope.
-            if it.def_id != self.def_id {
-                self.check(it.def_id);
+            if it.def_id.def_id != self.def_id {
+                self.check(it.def_id.def_id);
                 intravisit::walk_impl_item(self, it);
             }
         }
         fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) {
             trace!(?it.def_id);
-            self.check(it.def_id);
+            self.check(it.def_id.def_id);
             intravisit::walk_trait_item(self, it);
         }
     }
diff --git a/compiler/rustc_typeck/src/errors.rs b/compiler/rustc_typeck/src/errors.rs
index 14c0558cdde9..44df47e2fa00 100644
--- a/compiler/rustc_typeck/src/errors.rs
+++ b/compiler/rustc_typeck/src/errors.rs
@@ -1,11 +1,11 @@
 //! Errors emitted by typeck.
-use rustc_errors::{error_code, Applicability, DiagnosticBuilder, ErrorGuaranteed};
-use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
+use rustc_errors::IntoDiagnostic;
+use rustc_errors::{error_code, Applicability, DiagnosticBuilder, ErrorGuaranteed, Handler};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::Ty;
-use rustc_session::{parse::ParseSess, SessionDiagnostic};
 use rustc_span::{symbol::Ident, Span, Symbol};
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::field_multiply_specified_in_initializer, code = "E0062")]
 pub struct FieldMultiplySpecifiedInInitializer {
     #[primary_span]
@@ -16,7 +16,7 @@ pub struct FieldMultiplySpecifiedInInitializer {
     pub ident: Ident,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::unrecognized_atomic_operation, code = "E0092")]
 pub struct UnrecognizedAtomicOperation<'a> {
     #[primary_span]
@@ -25,7 +25,7 @@ pub struct UnrecognizedAtomicOperation<'a> {
     pub op: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::wrong_number_of_generic_arguments_to_intrinsic, code = "E0094")]
 pub struct WrongNumberOfGenericArgumentsToIntrinsic<'a> {
     #[primary_span]
@@ -36,7 +36,7 @@ pub struct WrongNumberOfGenericArgumentsToIntrinsic<'a> {
     pub descr: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::unrecognized_intrinsic_function, code = "E0093")]
 pub struct UnrecognizedIntrinsicFunction {
     #[primary_span]
@@ -45,7 +45,7 @@ pub struct UnrecognizedIntrinsicFunction {
     pub name: Symbol,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::lifetimes_or_bounds_mismatch_on_trait, code = "E0195")]
 pub struct LifetimesOrBoundsMismatchOnTrait {
     #[primary_span]
@@ -57,7 +57,7 @@ pub struct LifetimesOrBoundsMismatchOnTrait {
     pub ident: Ident,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::drop_impl_on_wrong_item, code = "E0120")]
 pub struct DropImplOnWrongItem {
     #[primary_span]
@@ -65,7 +65,7 @@ pub struct DropImplOnWrongItem {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::field_already_declared, code = "E0124")]
 pub struct FieldAlreadyDeclared {
     pub field_name: Ident,
@@ -76,7 +76,7 @@ pub struct FieldAlreadyDeclared {
     pub prev_span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::copy_impl_on_type_with_dtor, code = "E0184")]
 pub struct CopyImplOnTypeWithDtor {
     #[primary_span]
@@ -84,14 +84,14 @@ pub struct CopyImplOnTypeWithDtor {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::multiple_relaxed_default_bounds, code = "E0203")]
 pub struct MultipleRelaxedDefaultBounds {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::copy_impl_on_non_adt, code = "E0206")]
 pub struct CopyImplOnNonAdt {
     #[primary_span]
@@ -99,7 +99,7 @@ pub struct CopyImplOnNonAdt {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::trait_object_declared_with_no_traits, code = "E0224")]
 pub struct TraitObjectDeclaredWithNoTraits {
     #[primary_span]
@@ -108,14 +108,14 @@ pub struct TraitObjectDeclaredWithNoTraits {
     pub trait_alias_span: Option<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0227")]
 pub struct AmbiguousLifetimeBound {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::assoc_type_binding_not_allowed, code = "E0229")]
 pub struct AssocTypeBindingNotAllowed {
     #[primary_span]
@@ -123,14 +123,14 @@ pub struct AssocTypeBindingNotAllowed {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::functional_record_update_on_non_struct, code = "E0436")]
 pub struct FunctionalRecordUpdateOnNonStruct {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::typeof_reserved_keyword_used, code = "E0516")]
 pub struct TypeofReservedKeywordUsed<'tcx> {
     pub ty: Ty<'tcx>,
@@ -141,7 +141,7 @@ pub struct TypeofReservedKeywordUsed<'tcx> {
     pub opt_sugg: Option<(Span, Applicability)>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::return_stmt_outside_of_fn_body, code = "E0572")]
 pub struct ReturnStmtOutsideOfFnBody {
     #[primary_span]
@@ -152,14 +152,14 @@ pub struct ReturnStmtOutsideOfFnBody {
     pub encl_fn_span: Option<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::yield_expr_outside_of_generator, code = "E0627")]
 pub struct YieldExprOutsideOfGenerator {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::struct_expr_non_exhaustive, code = "E0639")]
 pub struct StructExprNonExhaustive {
     #[primary_span]
@@ -167,14 +167,14 @@ pub struct StructExprNonExhaustive {
     pub what: &'static str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::method_call_on_unknown_type, code = "E0699")]
 pub struct MethodCallOnUnknownType {
     #[primary_span]
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::value_of_associated_struct_already_specified, code = "E0719")]
 pub struct ValueOfAssociatedStructAlreadySpecified {
     #[primary_span]
@@ -186,7 +186,7 @@ pub struct ValueOfAssociatedStructAlreadySpecified {
     pub def_path: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::address_of_temporary_taken, code = "E0745")]
 pub struct AddressOfTemporaryTaken {
     #[primary_span]
@@ -194,7 +194,7 @@ pub struct AddressOfTemporaryTaken {
     pub span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum AddReturnTypeSuggestion {
     #[suggestion(
         typeck::add_return_type_add,
@@ -217,7 +217,7 @@ pub enum AddReturnTypeSuggestion {
     },
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 pub enum ExpectedReturnTypeLabel<'tcx> {
     #[label(typeck::expected_default_return_type)]
     Unit {
@@ -232,7 +232,7 @@ pub enum ExpectedReturnTypeLabel<'tcx> {
     },
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::unconstrained_opaque_type)]
 #[note]
 pub struct UnconstrainedOpaqueType {
@@ -244,14 +244,15 @@ pub struct UnconstrainedOpaqueType {
 pub struct MissingTypeParams {
     pub span: Span,
     pub def_span: Span,
+    pub span_snippet: Option<String>,
     pub missing_type_params: Vec<Symbol>,
     pub empty_generic_args: bool,
 }
 
-// Manual implementation of `SessionDiagnostic` to be able to call `span_to_snippet`.
-impl<'a> SessionDiagnostic<'a> for MissingTypeParams {
-    fn into_diagnostic(self, sess: &'a ParseSess) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        let mut err = sess.span_diagnostic.struct_span_err_with_code(
+// Manual implementation of `IntoDiagnostic` to be able to call `span_to_snippet`.
+impl<'a> IntoDiagnostic<'a> for MissingTypeParams {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+        let mut err = handler.struct_span_err_with_code(
             self.span,
             rustc_errors::fluent::typeck::missing_type_params,
             error_code!(E0393),
@@ -269,12 +270,9 @@ impl<'a> SessionDiagnostic<'a> for MissingTypeParams {
         err.span_label(self.def_span, rustc_errors::fluent::typeck::label);
 
         let mut suggested = false;
-        if let (Ok(snippet), true) = (
-            sess.source_map().span_to_snippet(self.span),
-            // Don't suggest setting the type params if there are some already: the order is
-            // tricky to get right and the user will already know what the syntax is.
-            self.empty_generic_args,
-        ) {
+        // Don't suggest setting the type params if there are some already: the order is
+        // tricky to get right and the user will already know what the syntax is.
+        if let Some(snippet) = self.span_snippet && self.empty_generic_args {
             if snippet.ends_with('>') {
                 // The user wrote `Trait<'a, T>` or similar. To provide an accurate suggestion
                 // we would have to preserve the right order. For now, as clearly the user is
@@ -308,7 +306,7 @@ impl<'a> SessionDiagnostic<'a> for MissingTypeParams {
     }
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::manual_implementation, code = "E0183")]
 #[help]
 pub struct ManualImplementation {
@@ -318,7 +316,7 @@ pub struct ManualImplementation {
     pub trait_name: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::substs_on_overridden_impl)]
 pub struct SubstsOnOverriddenImpl {
     #[primary_span]
@@ -341,7 +339,7 @@ pub struct ExternCrateNotIdiomatic {
     pub suggestion_code: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::expected_used_symbol)]
 pub struct ExpectedUsedSymbol {
     #[primary_span]
diff --git a/compiler/rustc_typeck/src/expr_use_visitor.rs b/compiler/rustc_typeck/src/expr_use_visitor.rs
index 74a5b6e42c30..f483342b445f 100644
--- a/compiler/rustc_typeck/src/expr_use_visitor.rs
+++ b/compiler/rustc_typeck/src/expr_use_visitor.rs
@@ -233,8 +233,9 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                 self.consume_exprs(args);
             }
 
-            hir::ExprKind::MethodCall(.., args, _) => {
+            hir::ExprKind::MethodCall(.., receiver, args, _) => {
                 // callee.m(args)
+                self.consume_expr(receiver);
                 self.consume_exprs(args);
             }
 
@@ -497,7 +498,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
         let expr_place = return_if_err!(self.mc.cat_expr(expr));
         f(self);
         if let Some(els) = els {
-            // borrowing because we need to test the descriminant
+            // borrowing because we need to test the discriminant
             self.maybe_read_scrutinee(expr, expr_place.clone(), from_ref(pat).iter());
             self.walk_block(els)
         }
diff --git a/compiler/rustc_typeck/src/impl_wf_check.rs b/compiler/rustc_typeck/src/impl_wf_check.rs
index 9fee1eaaec98..c499364056ff 100644
--- a/compiler/rustc_typeck/src/impl_wf_check.rs
+++ b/compiler/rustc_typeck/src/impl_wf_check.rs
@@ -58,10 +58,10 @@ fn check_mod_impl_wf(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
     let module = tcx.hir_module_items(module_def_id);
     for id in module.items() {
         if matches!(tcx.def_kind(id.def_id), DefKind::Impl) {
-            enforce_impl_params_are_constrained(tcx, id.def_id);
-            enforce_impl_items_are_distinct(tcx, id.def_id);
+            enforce_impl_params_are_constrained(tcx, id.def_id.def_id);
+            enforce_impl_items_are_distinct(tcx, id.def_id.def_id);
             if min_specialization {
-                check_min_specialization(tcx, id.def_id);
+                check_min_specialization(tcx, id.def_id.def_id);
             }
         }
     }
diff --git a/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs b/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
index 2741d9f776ce..5bebd7dee09b 100644
--- a/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
+++ b/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
@@ -423,13 +423,10 @@ fn trait_predicate_kind<'tcx>(
     predicate: ty::Predicate<'tcx>,
 ) -> Option<TraitSpecializationKind> {
     match predicate.kind().skip_binder() {
-        ty::PredicateKind::Trait(ty::TraitPredicate {
-            trait_ref,
-            constness: ty::BoundConstness::NotConst,
-            polarity: _,
-        }) => Some(tcx.trait_def(trait_ref.def_id).specialization_kind),
-        ty::PredicateKind::Trait(_)
-        | ty::PredicateKind::RegionOutlives(_)
+        ty::PredicateKind::Trait(ty::TraitPredicate { trait_ref, constness: _, polarity: _ }) => {
+            Some(tcx.trait_def(trait_ref.def_id).specialization_kind)
+        }
+        ty::PredicateKind::RegionOutlives(_)
         | ty::PredicateKind::TypeOutlives(_)
         | ty::PredicateKind::Projection(_)
         | ty::PredicateKind::WellFormed(_)
diff --git a/compiler/rustc_typeck/src/lib.rs b/compiler/rustc_typeck/src/lib.rs
index 8e910441a5d9..1859473166a7 100644
--- a/compiler/rustc_typeck/src/lib.rs
+++ b/compiler/rustc_typeck/src/lib.rs
@@ -64,9 +64,7 @@ This API is completely unstable and subject to change.
 #![feature(if_let_guard)]
 #![feature(is_sorted)]
 #![feature(iter_intersperse)]
-#![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(once_cell)]
@@ -444,7 +442,7 @@ fn check_start_fn_ty(tcx: TyCtxt<'_>, start_def_id: DefId) {
 
 fn check_for_entry_fn(tcx: TyCtxt<'_>) {
     match tcx.entry_fn(()) {
-        Some((def_id, EntryFnType::Main)) => check_main_fn_ty(tcx, def_id),
+        Some((def_id, EntryFnType::Main { .. })) => check_main_fn_ty(tcx, def_id),
         Some((def_id, EntryFnType::Start)) => check_start_fn_ty(tcx, def_id),
         _ => {}
     }
diff --git a/compiler/rustc_typeck/src/mem_categorization.rs b/compiler/rustc_typeck/src/mem_categorization.rs
index ced919f66db4..39610e3ae380 100644
--- a/compiler/rustc_typeck/src/mem_categorization.rs
+++ b/compiler/rustc_typeck/src/mem_categorization.rs
@@ -265,6 +265,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         self.cat_expr_adjusted_with(expr, || Ok(previous), adjustment)
     }
 
+    #[instrument(level = "debug", skip(self, previous))]
     fn cat_expr_adjusted_with<F>(
         &self,
         expr: &hir::Expr<'_>,
@@ -274,7 +275,6 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
     where
         F: FnOnce() -> McResult<PlaceWithHirId<'tcx>>,
     {
-        debug!("cat_expr_adjusted_with({:?}): {:?}", adjustment, expr);
         let target = self.resolve_vars_if_possible(adjustment.target);
         match adjustment.kind {
             adjustment::Adjust::Deref(overloaded) => {
@@ -299,6 +299,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn cat_expr_unadjusted(
         &self,
         expr: &hir::Expr<'_>,
@@ -387,6 +388,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self, span))]
     pub(crate) fn cat_res(
         &self,
         hir_id: hir::HirId,
@@ -394,8 +396,6 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         expr_ty: Ty<'tcx>,
         res: Res,
     ) -> McResult<PlaceWithHirId<'tcx>> {
-        debug!("cat_res: id={:?} expr={:?} def={:?}", hir_id, expr_ty, res);
-
         match res {
             Res::Def(
                 DefKind::Ctor(..)
@@ -475,13 +475,12 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         ret
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn cat_overloaded_place(
         &self,
         expr: &hir::Expr<'_>,
         base: &hir::Expr<'_>,
     ) -> McResult<PlaceWithHirId<'tcx>> {
-        debug!("cat_overloaded_place(expr={:?}, base={:?})", expr, base);
-
         // Reconstruct the output assuming it's a reference with the
         // same region and mutability as the receiver. This holds for
         // `Deref(Mut)::Deref(_mut)` and `Index(Mut)::index(_mut)`.
@@ -497,13 +496,12 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         self.cat_deref(expr, base)
     }
 
+    #[instrument(level = "debug", skip(self, node))]
     fn cat_deref(
         &self,
         node: &impl HirNode,
         base_place: PlaceWithHirId<'tcx>,
     ) -> McResult<PlaceWithHirId<'tcx>> {
-        debug!("cat_deref: base_place={:?}", base_place);
-
         let base_curr_ty = base_place.place.ty();
         let deref_ty = match base_curr_ty.builtin_deref(true) {
             Some(mt) => mt.ty,
diff --git a/compiler/rustc_typeck/src/outlives/implicit_infer.rs b/compiler/rustc_typeck/src/outlives/implicit_infer.rs
index 3b779280eda6..064a70107fe8 100644
--- a/compiler/rustc_typeck/src/outlives/implicit_infer.rs
+++ b/compiler/rustc_typeck/src/outlives/implicit_infer.rs
@@ -1,8 +1,8 @@
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst};
 use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt};
+use rustc_middle::ty::{GenericArg, GenericArgKind};
 use rustc_span::Span;
 
 use super::explicit::ExplicitPredicatesMap;
diff --git a/compiler/rustc_typeck/src/outlives/utils.rs b/compiler/rustc_typeck/src/outlives/utils.rs
index b718ca942133..0409c7081dc4 100644
--- a/compiler/rustc_typeck/src/outlives/utils.rs
+++ b/compiler/rustc_typeck/src/outlives/utils.rs
@@ -96,6 +96,23 @@ pub(crate) fn insert_outlives_predicate<'tcx>(
                             .or_insert(span);
                     }
 
+                    Component::Opaque(def_id, substs) => {
+                        // This would arise from something like:
+                        //
+                        // ```rust
+                        // type Opaque<T> = impl Sized;
+                        // fn defining<T>() -> Opaque<T> {}
+                        // struct Ss<'a, T>(&'a Opaque<T>);
+                        // ```
+                        //
+                        // Here we want to have an implied bound `Opaque<T>: 'a`
+
+                        let ty = tcx.mk_opaque(def_id, substs);
+                        required_predicates
+                            .entry(ty::OutlivesPredicate(ty.into(), outlived_region))
+                            .or_insert(span);
+                    }
+
                     Component::EscapingProjection(_) => {
                         // As above, but the projection involves
                         // late-bound regions.  Therefore, the WF
@@ -161,12 +178,6 @@ fn is_free_region(region: Region<'_>) -> bool {
         // ignore it.  We can't put it on the struct header anyway.
         ty::ReLateBound(..) => false,
 
-        // This can appear in `where Self: ` bounds (#64855):
-        //
-        //     struct Bar<T>(<Self as Foo>::Type) where Self: ;
-        //     struct Baz<'a>(&'a Self) where Self: ;
-        ty::ReEmpty(_) => false,
-
         // These regions don't appear in types from type declarations:
         ty::ReErased | ty::ReVar(..) | ty::RePlaceholder(..) | ty::ReFree(..) => {
             bug!("unexpected region in outlives inference: {:?}", region);
diff --git a/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs b/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs
index 6aa1c915542e..4359124646df 100644
--- a/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs
+++ b/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs
@@ -291,62 +291,60 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
     // Creates lifetime name suggestions from the lifetime parameter names
     fn get_lifetime_args_suggestions_from_param_names(
         &self,
-        path_hir_id: Option<hir::HirId>,
+        path_hir_id: hir::HirId,
         num_params_to_take: usize,
     ) -> String {
         debug!(?path_hir_id);
 
-        if let Some(path_hir_id) = path_hir_id {
-            let mut ret = Vec::new();
-            for (id, node) in self.tcx.hir().parent_iter(path_hir_id) {
-                debug!(?id);
-                let params = if let Some(generics) = node.generics() {
-                    generics.params
-                } else if let hir::Node::Ty(ty) = node
-                    && let hir::TyKind::BareFn(bare_fn) = ty.kind
-                {
-                    bare_fn.generic_params
-                } else {
-                    &[]
-                };
-                ret.extend(params.iter().filter_map(|p| {
-                    let hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }
-                        = p.kind
-                    else { return None };
-                    let hir::ParamName::Plain(name) = p.name else { return None };
-                    Some(name.to_string())
-                }));
-                // Suggest `'static` when in const/static item-like.
-                if let hir::Node::Item(hir::Item {
-                    kind: hir::ItemKind::Static { .. } | hir::ItemKind::Const { .. },
-                    ..
-                })
-                | hir::Node::TraitItem(hir::TraitItem {
-                    kind: hir::TraitItemKind::Const { .. },
-                    ..
-                })
-                | hir::Node::ImplItem(hir::ImplItem {
-                    kind: hir::ImplItemKind::Const { .. },
-                    ..
-                })
-                | hir::Node::ForeignItem(hir::ForeignItem {
-                    kind: hir::ForeignItemKind::Static { .. },
-                    ..
-                })
-                | hir::Node::AnonConst(..) = node
-                {
-                    ret.extend(
-                        std::iter::repeat("'static".to_owned())
-                            .take(num_params_to_take.saturating_sub(ret.len())),
-                    );
-                }
-                if ret.len() >= num_params_to_take {
-                    return ret[..num_params_to_take].join(", ");
-                }
-                // We cannot refer to lifetimes defined in an outer function.
-                if let hir::Node::Item(_) = node {
-                    break;
-                }
+        let mut ret = Vec::new();
+        for (id, node) in self.tcx.hir().parent_iter(path_hir_id) {
+            debug!(?id);
+            let params = if let Some(generics) = node.generics() {
+                generics.params
+            } else if let hir::Node::Ty(ty) = node
+                && let hir::TyKind::BareFn(bare_fn) = ty.kind
+            {
+                bare_fn.generic_params
+            } else {
+                &[]
+            };
+            ret.extend(params.iter().filter_map(|p| {
+                let hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }
+                    = p.kind
+                else { return None };
+                let hir::ParamName::Plain(name) = p.name else { return None };
+                Some(name.to_string())
+            }));
+            // Suggest `'static` when in const/static item-like.
+            if let hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Static { .. } | hir::ItemKind::Const { .. },
+                ..
+            })
+            | hir::Node::TraitItem(hir::TraitItem {
+                kind: hir::TraitItemKind::Const { .. },
+                ..
+            })
+            | hir::Node::ImplItem(hir::ImplItem {
+                kind: hir::ImplItemKind::Const { .. },
+                ..
+            })
+            | hir::Node::ForeignItem(hir::ForeignItem {
+                kind: hir::ForeignItemKind::Static { .. },
+                ..
+            })
+            | hir::Node::AnonConst(..) = node
+            {
+                ret.extend(
+                    std::iter::repeat("'static".to_owned())
+                        .take(num_params_to_take.saturating_sub(ret.len())),
+                );
+            }
+            if ret.len() >= num_params_to_take {
+                return ret[..num_params_to_take].join(", ");
+            }
+            // We cannot refer to lifetimes defined in an outer function.
+            if let hir::Node::Item(_) = node {
+                break;
             }
         }
 
@@ -523,6 +521,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
                 if self.not_enough_args_provided() {
                     self.suggest_adding_args(err);
                 } else if self.too_many_args_provided() {
+                    self.suggest_moving_args_from_assoc_fn_to_trait(err);
                     self.suggest_removing_args_or_generics(err);
                 } else {
                     unreachable!();
@@ -653,6 +652,144 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
         }
     }
 
+    /// Suggests moving redundant argument(s) of an associate function to the
+    /// trait it belongs to.
+    ///
+    /// ```compile_fail
+    /// Into::into::<Option<_>>(42) // suggests considering `Into::<Option<_>>::into(42)`
+    /// ```
+    fn suggest_moving_args_from_assoc_fn_to_trait(&self, err: &mut Diagnostic) {
+        let trait_ = match self.tcx.trait_of_item(self.def_id) {
+            Some(def_id) => def_id,
+            None => return,
+        };
+
+        // Skip suggestion when the associated function is itself generic, it is unclear
+        // how to split the provided parameters between those to suggest to the trait and
+        // those to remain on the associated type.
+        let num_assoc_fn_expected_args =
+            self.num_expected_type_or_const_args() + self.num_expected_lifetime_args();
+        if num_assoc_fn_expected_args > 0 {
+            return;
+        }
+
+        let num_assoc_fn_excess_args =
+            self.num_excess_type_or_const_args() + self.num_excess_lifetime_args();
+
+        let trait_generics = self.tcx.generics_of(trait_);
+        let num_trait_generics_except_self =
+            trait_generics.count() - if trait_generics.has_self { 1 } else { 0 };
+
+        let msg = format!(
+            "consider moving {these} generic argument{s} to the `{name}` trait, which takes up to {num} argument{s}",
+            these = pluralize!("this", num_assoc_fn_excess_args),
+            s = pluralize!(num_assoc_fn_excess_args),
+            name = self.tcx.item_name(trait_),
+            num = num_trait_generics_except_self,
+        );
+
+        if let Some(parent_node) = self.tcx.hir().find_parent_node(self.path_segment.hir_id)
+        && let Some(parent_node) = self.tcx.hir().find(parent_node)
+        && let hir::Node::Expr(expr) = parent_node {
+            match expr.kind {
+                hir::ExprKind::Path(ref qpath) => {
+                    self.suggest_moving_args_from_assoc_fn_to_trait_for_qualified_path(
+                        err,
+                        qpath,
+                        msg,
+                        num_assoc_fn_excess_args,
+                        num_trait_generics_except_self
+                    )
+                },
+                hir::ExprKind::MethodCall(..) => {
+                    self.suggest_moving_args_from_assoc_fn_to_trait_for_method_call(
+                        err,
+                        trait_,
+                        expr,
+                        msg,
+                        num_assoc_fn_excess_args,
+                        num_trait_generics_except_self
+                    )
+                },
+                _ => return,
+            }
+        }
+    }
+
+    fn suggest_moving_args_from_assoc_fn_to_trait_for_qualified_path(
+        &self,
+        err: &mut Diagnostic,
+        qpath: &'tcx hir::QPath<'tcx>,
+        msg: String,
+        num_assoc_fn_excess_args: usize,
+        num_trait_generics_except_self: usize,
+    ) {
+        if let hir::QPath::Resolved(_, path) = qpath
+        && let Some(trait_path_segment) = path.segments.get(0) {
+            let num_generic_args_supplied_to_trait = trait_path_segment.args().num_generic_params();
+
+            if num_assoc_fn_excess_args == num_trait_generics_except_self - num_generic_args_supplied_to_trait {
+                if let Some(span) = self.gen_args.span_ext()
+                && let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
+                    let sugg = vec![
+                        (self.path_segment.ident.span, format!("{}::{}", snippet, self.path_segment.ident)),
+                        (span.with_lo(self.path_segment.ident.span.hi()), "".to_owned())
+                    ];
+
+                    err.multipart_suggestion(
+                        msg,
+                        sugg,
+                        Applicability::MaybeIncorrect
+                    );
+                }
+            }
+        }
+    }
+
+    fn suggest_moving_args_from_assoc_fn_to_trait_for_method_call(
+        &self,
+        err: &mut Diagnostic,
+        trait_def_id: DefId,
+        expr: &'tcx hir::Expr<'tcx>,
+        msg: String,
+        num_assoc_fn_excess_args: usize,
+        num_trait_generics_except_self: usize,
+    ) {
+        let sm = self.tcx.sess.source_map();
+        let hir::ExprKind::MethodCall(_, rcvr, args, _) = expr.kind else { return; };
+        if num_assoc_fn_excess_args != num_trait_generics_except_self {
+            return;
+        }
+        let Some(gen_args) = self.gen_args.span_ext() else { return; };
+        let Ok(generics) = sm.span_to_snippet(gen_args) else { return; };
+        let Ok(rcvr) = sm.span_to_snippet(
+            rcvr.span.find_ancestor_inside(expr.span).unwrap_or(rcvr.span)
+        ) else { return; };
+        let Ok(rest) =
+            (match args {
+                [] => Ok(String::new()),
+                [arg] => sm.span_to_snippet(
+                    arg.span.find_ancestor_inside(expr.span).unwrap_or(arg.span),
+                ),
+                [first, .., last] => {
+                    let first_span =
+                        first.span.find_ancestor_inside(expr.span).unwrap_or(first.span);
+                    let last_span =
+                        last.span.find_ancestor_inside(expr.span).unwrap_or(last.span);
+                    sm.span_to_snippet(first_span.to(last_span))
+                }
+            }) else { return; };
+        let comma = if args.len() > 0 { ", " } else { "" };
+        let trait_path = self.tcx.def_path_str(trait_def_id);
+        let method_name = self.tcx.item_name(self.def_id);
+        err.span_suggestion(
+            expr.span,
+            msg,
+            format!("{trait_path}::{generics}::{method_name}({rcvr}{comma}{rest})"),
+            Applicability::MaybeIncorrect,
+        );
+    }
+
     /// Suggests to remove redundant argument(s):
     ///
     /// ```text
diff --git a/compiler/rustc_typeck/src/variance/constraints.rs b/compiler/rustc_typeck/src/variance/constraints.rs
index d79450e1ae70..eaf0310d57ae 100644
--- a/compiler/rustc_typeck/src/variance/constraints.rs
+++ b/compiler/rustc_typeck/src/variance/constraints.rs
@@ -257,7 +257,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 self.add_constraints_from_invariant_substs(current, substs, variance);
             }
 
-            ty::Dynamic(data, r) => {
+            ty::Dynamic(data, r, _) => {
                 // The type `Foo<T+'a>` is contravariant w/r/t `'a`:
                 let contra = self.contravariant(variance);
                 self.add_constraints_from_region(current, r, contra);
@@ -271,11 +271,11 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 }
 
                 for projection in data.projection_bounds() {
-                    match projection.skip_binder().term {
-                        ty::Term::Ty(ty) => {
+                    match projection.skip_binder().term.unpack() {
+                        ty::TermKind::Ty(ty) => {
                             self.add_constraints_from_ty(current, ty, self.invariant);
                         }
-                        ty::Term::Const(c) => {
+                        ty::TermKind::Const(c) => {
                             self.add_constraints_from_const(current, c, self.invariant)
                         }
                     }
@@ -411,11 +411,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 // way early-bound regions do, so we skip them here.
             }
 
-            ty::ReFree(..)
-            | ty::ReVar(..)
-            | ty::RePlaceholder(..)
-            | ty::ReEmpty(_)
-            | ty::ReErased => {
+            ty::ReFree(..) | ty::ReVar(..) | ty::RePlaceholder(..) | ty::ReErased => {
                 // We don't expect to see anything but 'static or bound
                 // regions when visiting member types or method types.
                 bug!(
diff --git a/config.toml.example b/config.toml.example
index b320cdcc109d..a967d881b029 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -666,6 +666,10 @@ changelog-seen = 2
 # target.
 #llvm-config = <none> (path)
 
+# Override detection of whether this is a Rust-patched LLVM. This would be used
+# in conjunction with either an llvm-config or build.submodules = false.
+#llvm-has-rust-patches = if llvm-config { false } else { true }
+
 # Normally the build system can find LLVM's FileCheck utility, but if
 # not, you can specify an explicit file name for it.
 #llvm-filecheck = "/path/to/llvm-version/bin/FileCheck"
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index 65e323c9e00c..f651cb021769 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -151,7 +151,6 @@ use core::async_iter::AsyncIterator;
 use core::borrow;
 use core::cmp::Ordering;
 use core::convert::{From, TryFrom};
-#[cfg(not(bootstrap))]
 use core::error::Error;
 use core::fmt;
 use core::future::Future;
@@ -176,7 +175,6 @@ use crate::borrow::Cow;
 use crate::raw_vec::RawVec;
 #[cfg(not(no_global_oom_handling))]
 use crate::str::from_boxed_utf8_unchecked;
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 use crate::string::String;
 #[cfg(not(no_global_oom_handling))]
@@ -2037,8 +2035,7 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for Box<T, A> {
  *  could have a method to project a Pin<T> from it.
  */
 #[stable(feature = "pin", since = "1.33.0")]
-#[rustc_const_unstable(feature = "const_box", issue = "92521")]
-impl<T: ?Sized, A: Allocator> const Unpin for Box<T, A> where A: 'static {}
+impl<T: ?Sized, A: Allocator> Unpin for Box<T, A> where A: 'static {}
 
 #[unstable(feature = "generator_trait", issue = "43122")]
 impl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>
@@ -2091,7 +2088,6 @@ impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S> {
     }
 }
 
-#[cfg(not(bootstrap))]
 impl dyn Error {
     #[inline]
     #[stable(feature = "error_downcast", since = "1.3.0")]
@@ -2109,7 +2105,6 @@ impl dyn Error {
     }
 }
 
-#[cfg(not(bootstrap))]
 impl dyn Error + Send {
     #[inline]
     #[stable(feature = "error_downcast", since = "1.3.0")]
@@ -2124,7 +2119,6 @@ impl dyn Error + Send {
     }
 }
 
-#[cfg(not(bootstrap))]
 impl dyn Error + Send + Sync {
     #[inline]
     #[stable(feature = "error_downcast", since = "1.3.0")]
@@ -2139,7 +2133,6 @@ impl dyn Error + Send + Sync {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
@@ -2173,7 +2166,6 @@ impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> {
@@ -2213,7 +2205,6 @@ impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync +
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl From<String> for Box<dyn Error + Send + Sync> {
@@ -2258,7 +2249,6 @@ impl From<String> for Box<dyn Error + Send + Sync> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "string_box_error", since = "1.6.0")]
 impl From<String> for Box<dyn Error> {
@@ -2281,7 +2271,6 @@ impl From<String> for Box<dyn Error> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
@@ -2306,7 +2295,6 @@ impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "string_box_error", since = "1.6.0")]
 impl From<&str> for Box<dyn Error> {
@@ -2329,7 +2317,6 @@ impl From<&str> for Box<dyn Error> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "cow_box_error", since = "1.22.0")]
 impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
@@ -2352,7 +2339,6 @@ impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "cow_box_error", since = "1.22.0")]
 impl<'a> From<Cow<'a, str>> for Box<dyn Error> {
@@ -2374,7 +2360,6 @@ impl<'a> From<Cow<'a, str>> for Box<dyn Error> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "box_error", since = "1.8.0")]
 impl<T: core::error::Error> core::error::Error for Box<T> {
     #[allow(deprecated, deprecated_in_future)]
diff --git a/library/alloc/src/boxed/thin.rs b/library/alloc/src/boxed/thin.rs
index 0a20c74b00fd..c477c44906c9 100644
--- a/library/alloc/src/boxed/thin.rs
+++ b/library/alloc/src/boxed/thin.rs
@@ -2,7 +2,6 @@
 // https://github.com/matthieu-m/rfc2580/blob/b58d1d3cba0d4b5e859d3617ea2d0943aaa31329/examples/thin.rs
 // by matthieu-m
 use crate::alloc::{self, Layout, LayoutError};
-#[cfg(not(bootstrap))]
 use core::error::Error;
 use core::fmt::{self, Debug, Display, Formatter};
 use core::marker::PhantomData;
@@ -274,7 +273,6 @@ impl<H> WithHeader<H> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[unstable(feature = "thin_box", issue = "92791")]
 impl<T: ?Sized + Error> Error for ThinBox<T> {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
diff --git a/library/alloc/src/collections/btree/dedup_sorted_iter.rs b/library/alloc/src/collections/btree/dedup_sorted_iter.rs
index 60bf83b8387c..17ee78045a9b 100644
--- a/library/alloc/src/collections/btree/dedup_sorted_iter.rs
+++ b/library/alloc/src/collections/btree/dedup_sorted_iter.rs
@@ -3,7 +3,9 @@ use core::iter::Peekable;
 /// A iterator for deduping the key of a sorted iterator.
 /// When encountering the duplicated key, only the last key-value pair is yielded.
 ///
-/// Used by [`BTreeMap::bulk_build_from_sorted_iter`].
+/// Used by [`BTreeMap::bulk_build_from_sorted_iter`][1].
+///
+/// [1]: crate::collections::BTreeMap::bulk_build_from_sorted_iter
 pub struct DedupSortedIter<K, V, I>
 where
     I: Iterator<Item = (K, V)>,
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index cacbd54b6c24..3018d1c9125b 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -580,7 +580,7 @@ impl<K, V> BTreeMap<K, V> {
     /// map.insert(1, "a");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    #[rustc_const_stable(feature = "const_btree_new", since = "CURRENT_RUSTC_VERSION")]
     #[must_use]
     pub const fn new() -> BTreeMap<K, V> {
         BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(Global), _marker: PhantomData }
@@ -2392,7 +2392,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
     /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    #[rustc_const_unstable(feature = "const_btree_len", issue = "71835")]
     pub const fn len(&self) -> usize {
         self.length
     }
@@ -2413,7 +2413,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
     /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    #[rustc_const_unstable(feature = "const_btree_len", issue = "71835")]
     pub const fn is_empty(&self) -> bool {
         self.len() == 0
     }
diff --git a/library/alloc/src/collections/btree/map/entry.rs b/library/alloc/src/collections/btree/map/entry.rs
index cd7cdc192071..370b58864af8 100644
--- a/library/alloc/src/collections/btree/map/entry.rs
+++ b/library/alloc/src/collections/btree/map/entry.rs
@@ -133,7 +133,6 @@ impl<'a, K: Debug + Ord, V: Debug, A: Allocator + Clone> fmt::Display
     }
 }
 
-#[cfg(not(bootstrap))]
 #[unstable(feature = "map_try_insert", issue = "82766")]
 impl<'a, K: core::fmt::Debug + Ord, V: core::fmt::Debug> core::error::Error
     for crate::collections::btree_map::OccupiedError<'a, K, V>
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index 2cfc08074092..3caaf521240d 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -343,7 +343,7 @@ impl<T> BTreeSet<T> {
     /// let mut set: BTreeSet<i32> = BTreeSet::new();
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    #[rustc_const_stable(feature = "const_btree_new", since = "CURRENT_RUSTC_VERSION")]
     #[must_use]
     pub const fn new() -> BTreeSet<T> {
         BTreeSet { map: BTreeMap::new() }
@@ -1174,7 +1174,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    #[rustc_const_unstable(feature = "const_btree_len", issue = "71835")]
     pub const fn len(&self) -> usize {
         self.map.len()
     }
@@ -1193,7 +1193,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    #[rustc_const_unstable(feature = "const_btree_len", issue = "71835")]
     pub const fn is_empty(&self) -> bool {
         self.len() == 0
     }
diff --git a/library/alloc/src/collections/linked_list.rs b/library/alloc/src/collections/linked_list.rs
index e21c8aa3bd53..6480fcaf93d4 100644
--- a/library/alloc/src/collections/linked_list.rs
+++ b/library/alloc/src/collections/linked_list.rs
@@ -1570,7 +1570,7 @@ impl<'a, T> CursorMut<'a, T> {
     /// that the cursor points to is unchanged, even if it is the "ghost" node.
     ///
     /// This operation should compute in *O*(1) time.
-    // `push_front` continues to point to "ghost" when it addes a node to mimic
+    // `push_front` continues to point to "ghost" when it adds a node to mimic
     // the behavior of `insert_before` on an empty list.
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
     pub fn push_front(&mut self, elt: T) {
diff --git a/library/alloc/src/collections/mod.rs b/library/alloc/src/collections/mod.rs
index 21d0def0866e..161a375736c6 100644
--- a/library/alloc/src/collections/mod.rs
+++ b/library/alloc/src/collections/mod.rs
@@ -153,6 +153,5 @@ trait SpecExtend<I: IntoIterator> {
     fn spec_extend(&mut self, iter: I);
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "try_reserve", since = "1.57.0")]
 impl core::error::Error for TryReserveError {}
diff --git a/library/alloc/src/collections/vec_deque/drain.rs b/library/alloc/src/collections/vec_deque/drain.rs
index 05f94da6de70..41baa7102cdc 100644
--- a/library/alloc/src/collections/vec_deque/drain.rs
+++ b/library/alloc/src/collections/vec_deque/drain.rs
@@ -1,10 +1,12 @@
+use core::fmt;
 use core::iter::FusedIterator;
+use core::marker::PhantomData;
+use core::mem::{self, MaybeUninit};
 use core::ptr::{self, NonNull};
-use core::{fmt, mem};
 
 use crate::alloc::{Allocator, Global};
 
-use super::{count, Iter, VecDeque};
+use super::{count, wrap_index, VecDeque};
 
 /// A draining iterator over the elements of a `VecDeque`.
 ///
@@ -20,18 +22,24 @@ pub struct Drain<
 > {
     after_tail: usize,
     after_head: usize,
-    iter: Iter<'a, T>,
+    ring: NonNull<[T]>,
+    tail: usize,
+    head: usize,
     deque: NonNull<VecDeque<T, A>>,
+    _phantom: PhantomData<&'a T>,
 }
 
 impl<'a, T, A: Allocator> Drain<'a, T, A> {
     pub(super) unsafe fn new(
         after_tail: usize,
         after_head: usize,
-        iter: Iter<'a, T>,
+        ring: &'a [MaybeUninit<T>],
+        tail: usize,
+        head: usize,
         deque: NonNull<VecDeque<T, A>>,
     ) -> Self {
-        Drain { after_tail, after_head, iter, deque }
+        let ring = unsafe { NonNull::new_unchecked(ring as *const [MaybeUninit<T>] as *mut _) };
+        Drain { after_tail, after_head, ring, tail, head, deque, _phantom: PhantomData }
     }
 }
 
@@ -41,7 +49,9 @@ impl<T: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, T, A> {
         f.debug_tuple("Drain")
             .field(&self.after_tail)
             .field(&self.after_head)
-            .field(&self.iter)
+            .field(&self.ring)
+            .field(&self.tail)
+            .field(&self.head)
             .finish()
     }
 }
@@ -118,12 +128,21 @@ impl<T, A: Allocator> Iterator for Drain<'_, T, A> {
 
     #[inline]
     fn next(&mut self) -> Option<T> {
-        self.iter.next().map(|elt| unsafe { ptr::read(elt) })
+        if self.tail == self.head {
+            return None;
+        }
+        let tail = self.tail;
+        self.tail = wrap_index(self.tail.wrapping_add(1), self.ring.len());
+        // Safety:
+        // - `self.tail` in a ring buffer is always a valid index.
+        // - `self.head` and `self.tail` equality is checked above.
+        unsafe { Some(ptr::read(self.ring.as_ptr().get_unchecked_mut(tail))) }
     }
 
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
+        let len = count(self.tail, self.head, self.ring.len());
+        (len, Some(len))
     }
 }
 
@@ -131,7 +150,14 @@ impl<T, A: Allocator> Iterator for Drain<'_, T, A> {
 impl<T, A: Allocator> DoubleEndedIterator for Drain<'_, T, A> {
     #[inline]
     fn next_back(&mut self) -> Option<T> {
-        self.iter.next_back().map(|elt| unsafe { ptr::read(elt) })
+        if self.tail == self.head {
+            return None;
+        }
+        self.head = wrap_index(self.head.wrapping_sub(1), self.ring.len());
+        // Safety:
+        // - `self.head` in a ring buffer is always a valid index.
+        // - `self.head` and `self.tail` equality is checked above.
+        unsafe { Some(ptr::read(self.ring.as_ptr().get_unchecked_mut(self.head))) }
     }
 }
 
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index 347a938fd0c5..2a57dad89a77 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -12,11 +12,17 @@ use core::fmt;
 use core::hash::{Hash, Hasher};
 use core::iter::{repeat_with, FromIterator};
 use core::marker::PhantomData;
-use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::mem::{ManuallyDrop, MaybeUninit, SizedTypeProperties};
 use core::ops::{Index, IndexMut, Range, RangeBounds};
 use core::ptr::{self, NonNull};
 use core::slice;
 
+// This is used in a bunch of intra-doc links.
+// FIXME: For some reason, `#[cfg(doc)]` wasn't sufficient, resulting in
+// failures in linkchecker even though rustdoc built the docs just fine.
+#[allow(unused_imports)]
+use core::mem;
+
 use crate::alloc::{Allocator, Global};
 use crate::collections::TryReserveError;
 use crate::collections::TryReserveErrorKind;
@@ -177,7 +183,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// Marginally more convenient
     #[inline]
     fn cap(&self) -> usize {
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // For zero sized types, we are always at maximum capacity
             MAXIMUM_ZST_CAPACITY
         } else {
@@ -1334,9 +1340,8 @@ impl<T, A: Allocator> VecDeque<T, A> {
             // it.  We do not write to `self` nor reborrow to a mutable reference.
             // Hence the raw pointer we created above, for `deque`, remains valid.
             let ring = self.buffer_as_slice();
-            let iter = Iter::new(ring, drain_tail, drain_head);
 
-            Drain::new(drain_head, head, iter, deque)
+            Drain::new(drain_head, head, ring, drain_tail, drain_head, deque)
         }
     }
 
@@ -3039,7 +3044,7 @@ impl<T, A: Allocator> From<Vec<T, A>> for VecDeque<T, A> {
     /// `Vec<T>` came from `From<VecDeque<T>>` and hasn't been reallocated.
     fn from(mut other: Vec<T, A>) -> Self {
         let len = other.len();
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // There's no actual allocation for ZSTs to worry about capacity,
             // but `VecDeque` can't handle as much length as `Vec`.
             assert!(len < MAXIMUM_ZST_CAPACITY, "capacity overflow");
@@ -3125,7 +3130,7 @@ impl<T, const N: usize> From<[T; N]> for VecDeque<T> {
     fn from(arr: [T; N]) -> Self {
         let mut deq = VecDeque::with_capacity(N);
         let arr = ManuallyDrop::new(arr);
-        if mem::size_of::<T>() != 0 {
+        if !<T>::IS_ZST {
             // SAFETY: VecDeque::with_capacity ensures that there is enough capacity.
             unsafe {
                 ptr::copy_nonoverlapping(arr.as_ptr(), deq.ptr(), N);
diff --git a/library/alloc/src/ffi/c_str.rs b/library/alloc/src/ffi/c_str.rs
index aede6d54c6c1..11bd4c4dc1ba 100644
--- a/library/alloc/src/ffi/c_str.rs
+++ b/library/alloc/src/ffi/c_str.rs
@@ -1122,7 +1122,6 @@ impl CStr {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl core::error::Error for NulError {
     #[allow(deprecated)]
@@ -1131,11 +1130,9 @@ impl core::error::Error for NulError {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
 impl core::error::Error for FromVecWithNulError {}
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "cstring_into", since = "1.7.0")]
 impl core::error::Error for IntoStringError {
     #[allow(deprecated)]
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index ad6d19bbc687..7fde8f670a23 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -69,6 +69,8 @@
     any(not(feature = "miri-test-libstd"), test, doctest),
     no_global_oom_handling,
     not(no_global_oom_handling),
+    not(no_rc),
+    not(no_sync),
     target_has_atomic = "ptr"
 ))]
 #![no_std]
@@ -97,7 +99,7 @@
 #![feature(coerce_unsized)]
 #![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))]
 #![feature(const_box)]
-#![cfg_attr(not(no_global_oom_handling), feature(const_btree_new))]
+#![cfg_attr(not(no_global_oom_handling), feature(const_btree_len))]
 #![feature(const_cow_is_borrowed)]
 #![feature(const_convert)]
 #![feature(const_size_of_val)]
@@ -109,10 +111,11 @@
 #![feature(core_intrinsics)]
 #![feature(const_eval_select)]
 #![feature(const_pin)]
+#![feature(const_waker)]
 #![feature(cstr_from_bytes_until_nul)]
 #![feature(dispatch_from_dyn)]
-#![cfg_attr(not(bootstrap), feature(error_generic_member_access))]
-#![cfg_attr(not(bootstrap), feature(error_in_core))]
+#![feature(error_generic_member_access)]
+#![feature(error_in_core)]
 #![feature(exact_size_is_empty)]
 #![feature(extend_one)]
 #![feature(fmt_internals)]
@@ -129,12 +132,14 @@
 #![feature(nonnull_slice_from_raw_parts)]
 #![feature(pattern)]
 #![feature(pointer_byte_offsets)]
-#![cfg_attr(not(bootstrap), feature(provide_any))]
+#![feature(provide_any)]
 #![feature(ptr_internals)]
 #![feature(ptr_metadata)]
 #![feature(ptr_sub_ptr)]
 #![feature(receiver_trait)]
+#![feature(saturating_int_impl)]
 #![feature(set_ptr_value)]
+#![feature(sized_type_properties)]
 #![feature(slice_from_ptr_range)]
 #![feature(slice_group_by)]
 #![feature(slice_ptr_get)]
@@ -168,7 +173,6 @@
 #![cfg_attr(not(test), feature(generator_trait))]
 #![feature(hashmap_internals)]
 #![feature(lang_items)]
-#![feature(let_else)]
 #![feature(min_specialization)]
 #![feature(negative_impls)]
 #![feature(never_type)]
@@ -223,16 +227,17 @@ mod boxed {
 }
 pub mod borrow;
 pub mod collections;
-#[cfg(not(no_global_oom_handling))]
+#[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
 pub mod ffi;
 pub mod fmt;
+#[cfg(not(no_rc))]
 pub mod rc;
 pub mod slice;
 pub mod str;
 pub mod string;
-#[cfg(target_has_atomic = "ptr")]
+#[cfg(all(not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
 pub mod sync;
-#[cfg(all(not(no_global_oom_handling), target_has_atomic = "ptr"))]
+#[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
 pub mod task;
 #[cfg(test)]
 mod tests;
diff --git a/library/alloc/src/raw_vec.rs b/library/alloc/src/raw_vec.rs
index b0f4529abdfa..5a10121bbbe4 100644
--- a/library/alloc/src/raw_vec.rs
+++ b/library/alloc/src/raw_vec.rs
@@ -3,7 +3,7 @@
 use core::alloc::LayoutError;
 use core::cmp;
 use core::intrinsics;
-use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
 use core::ops::Drop;
 use core::ptr::{self, NonNull, Unique};
 use core::slice;
@@ -168,7 +168,7 @@ impl<T, A: Allocator> RawVec<T, A> {
     #[cfg(not(no_global_oom_handling))]
     fn allocate_in(capacity: usize, init: AllocInit, alloc: A) -> Self {
         // Don't allocate here because `Drop` will not deallocate when `capacity` is 0.
-        if mem::size_of::<T>() == 0 || capacity == 0 {
+        if T::IS_ZST || capacity == 0 {
             Self::new_in(alloc)
         } else {
             // We avoid `unwrap_or_else` here because it bloats the amount of
@@ -229,7 +229,7 @@ impl<T, A: Allocator> RawVec<T, A> {
     /// This will always be `usize::MAX` if `T` is zero-sized.
     #[inline(always)]
     pub fn capacity(&self) -> usize {
-        if mem::size_of::<T>() == 0 { usize::MAX } else { self.cap }
+        if T::IS_ZST { usize::MAX } else { self.cap }
     }
 
     /// Returns a shared reference to the allocator backing this `RawVec`.
@@ -238,7 +238,7 @@ impl<T, A: Allocator> RawVec<T, A> {
     }
 
     fn current_memory(&self) -> Option<(NonNull<u8>, Layout)> {
-        if mem::size_of::<T>() == 0 || self.cap == 0 {
+        if T::IS_ZST || self.cap == 0 {
             None
         } else {
             // We have an allocated chunk of memory, so we can bypass runtime
@@ -380,7 +380,7 @@ impl<T, A: Allocator> RawVec<T, A> {
         // This is ensured by the calling contexts.
         debug_assert!(additional > 0);
 
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // Since we return a capacity of `usize::MAX` when `elem_size` is
             // 0, getting to here necessarily means the `RawVec` is overfull.
             return Err(CapacityOverflow.into());
@@ -406,7 +406,7 @@ impl<T, A: Allocator> RawVec<T, A> {
     // `grow_amortized`, but this method is usually instantiated less often so
     // it's less critical.
     fn grow_exact(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // Since we return a capacity of `usize::MAX` when the type size is
             // 0, getting to here necessarily means the `RawVec` is overfull.
             return Err(CapacityOverflow.into());
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index b89b03683bae..6d247681c666 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -1142,7 +1142,7 @@ impl<T: Clone> Rc<T> {
     /// be cloned.
     ///
     /// See also [`get_mut`], which will fail rather than cloning the inner value
-    /// or diassociating [`Weak`] pointers.
+    /// or disassociating [`Weak`] pointers.
     ///
     /// [`clone`]: Clone::clone
     /// [`get_mut`]: Rc::get_mut
diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs
index bcd3f49e2089..a5e7bf2a1a9f 100644
--- a/library/alloc/src/slice.rs
+++ b/library/alloc/src/slice.rs
@@ -16,9 +16,7 @@ use core::borrow::{Borrow, BorrowMut};
 #[cfg(not(no_global_oom_handling))]
 use core::cmp::Ordering::{self, Less};
 #[cfg(not(no_global_oom_handling))]
-use core::mem;
-#[cfg(not(no_global_oom_handling))]
-use core::mem::size_of;
+use core::mem::{self, SizedTypeProperties};
 #[cfg(not(no_global_oom_handling))]
 use core::ptr;
 
@@ -205,7 +203,7 @@ impl<T> [T] {
     where
         T: Ord,
     {
-        merge_sort(self, |a, b| a.lt(b));
+        merge_sort(self, T::lt);
     }
 
     /// Sorts the slice with a comparator function.
@@ -1018,7 +1016,7 @@ where
     const MIN_RUN: usize = 10;
 
     // Sorting has no meaningful behavior on zero-sized types.
-    if size_of::<T>() == 0 {
+    if T::IS_ZST {
         return;
     }
 
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index f2448396ce8d..983376a282be 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -44,7 +44,6 @@
 
 #[cfg(not(no_global_oom_handling))]
 use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
-#[cfg(not(bootstrap))]
 use core::error::Error;
 use core::fmt;
 use core::hash;
@@ -1941,7 +1940,6 @@ impl fmt::Display for FromUtf16Error {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Error for FromUtf8Error {
     #[allow(deprecated)]
@@ -1950,7 +1948,6 @@ impl Error for FromUtf8Error {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Error for FromUtf16Error {
     #[allow(deprecated)]
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 4377edeee871..a5322953d492 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -2764,7 +2764,6 @@ fn data_offset_align(align: usize) -> usize {
     layout.size() + layout.padding_needed_for(align)
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "arc_error", since = "1.52.0")]
 impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> {
     #[allow(deprecated, deprecated_in_future)]
diff --git a/library/alloc/src/vec/drain.rs b/library/alloc/src/vec/drain.rs
index 5b73906a1c97..541f99bcfaba 100644
--- a/library/alloc/src/vec/drain.rs
+++ b/library/alloc/src/vec/drain.rs
@@ -1,7 +1,7 @@
 use crate::alloc::{Allocator, Global};
 use core::fmt;
 use core::iter::{FusedIterator, TrustedLen};
-use core::mem::{self, ManuallyDrop};
+use core::mem::{self, ManuallyDrop, SizedTypeProperties};
 use core::ptr::{self, NonNull};
 use core::slice::{self};
 
@@ -202,7 +202,7 @@ impl<T, A: Allocator> Drop for Drain<'_, T, A> {
 
         let mut vec = self.vec;
 
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // ZSTs have no identity, so we don't need to move them around, we only need to drop the correct amount.
             // this can be achieved by manipulating the Vec length instead of moving values out from `iter`.
             unsafe {
diff --git a/library/alloc/src/vec/in_place_collect.rs b/library/alloc/src/vec/in_place_collect.rs
index b211421b2027..a3f8fe40fd5c 100644
--- a/library/alloc/src/vec/in_place_collect.rs
+++ b/library/alloc/src/vec/in_place_collect.rs
@@ -135,7 +135,7 @@
 //! vec.truncate(write_idx);
 //! ```
 use core::iter::{InPlaceIterable, SourceIter, TrustedRandomAccessNoCoerce};
-use core::mem::{self, ManuallyDrop};
+use core::mem::{self, ManuallyDrop, SizedTypeProperties};
 use core::ptr::{self};
 
 use super::{InPlaceDrop, SpecFromIter, SpecFromIterNested, Vec};
@@ -154,7 +154,7 @@ where
     default fn from_iter(mut iterator: I) -> Self {
         // See "Layout constraints" section in the module documentation. We rely on const
         // optimization here since these conditions currently cannot be expressed as trait bounds
-        if mem::size_of::<T>() == 0
+        if T::IS_ZST
             || mem::size_of::<T>()
                 != mem::size_of::<<<I as SourceIter>::Source as AsVecIntoIter>::Item>()
             || mem::align_of::<T>()
diff --git a/library/alloc/src/vec/into_iter.rs b/library/alloc/src/vec/into_iter.rs
index b4157fd58954..d74e77637bdc 100644
--- a/library/alloc/src/vec/into_iter.rs
+++ b/library/alloc/src/vec/into_iter.rs
@@ -8,7 +8,7 @@ use core::iter::{
     FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce,
 };
 use core::marker::PhantomData;
-use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
 #[cfg(not(no_global_oom_handling))]
 use core::ops::Deref;
 use core::ptr::{self, NonNull};
@@ -149,7 +149,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
     fn next(&mut self) -> Option<T> {
         if self.ptr == self.end {
             None
-        } else if mem::size_of::<T>() == 0 {
+        } else if T::IS_ZST {
             // purposefully don't use 'ptr.offset' because for
             // vectors with 0-size elements this would return the
             // same pointer.
@@ -167,7 +167,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
 
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
-        let exact = if mem::size_of::<T>() == 0 {
+        let exact = if T::IS_ZST {
             self.end.addr().wrapping_sub(self.ptr.addr())
         } else {
             unsafe { self.end.sub_ptr(self.ptr) }
@@ -179,7 +179,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
     fn advance_by(&mut self, n: usize) -> Result<(), usize> {
         let step_size = self.len().min(n);
         let to_drop = ptr::slice_from_raw_parts_mut(self.ptr as *mut T, step_size);
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // SAFETY: due to unchecked casts of unsigned amounts to signed offsets the wraparound
             // effectively results in unsigned pointers representing positions 0..usize::MAX,
             // which is valid for ZSTs.
@@ -209,7 +209,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
 
         let len = self.len();
 
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             if len < N {
                 self.forget_remaining_elements();
                 // Safety: ZSTs can be conjured ex nihilo, only the amount has to be correct
@@ -253,7 +253,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
         // that `T: Copy` so reading elements from the buffer doesn't invalidate
         // them for `Drop`.
         unsafe {
-            if mem::size_of::<T>() == 0 { mem::zeroed() } else { ptr::read(self.ptr.add(i)) }
+            if T::IS_ZST { mem::zeroed() } else { ptr::read(self.ptr.add(i)) }
         }
     }
 }
@@ -264,7 +264,7 @@ impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
     fn next_back(&mut self) -> Option<T> {
         if self.end == self.ptr {
             None
-        } else if mem::size_of::<T>() == 0 {
+        } else if T::IS_ZST {
             // See above for why 'ptr.offset' isn't used
             self.end = self.end.wrapping_byte_sub(1);
 
@@ -280,7 +280,7 @@ impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
     #[inline]
     fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
         let step_size = self.len().min(n);
-        if mem::size_of::<T>() == 0 {
+        if T::IS_ZST {
             // SAFETY: same as for advance_by()
             self.end = self.end.wrapping_byte_sub(step_size);
         } else {
diff --git a/library/alloc/src/vec/is_zero.rs b/library/alloc/src/vec/is_zero.rs
index 92a32779b8e6..2e025c8a4a5d 100644
--- a/library/alloc/src/vec/is_zero.rs
+++ b/library/alloc/src/vec/is_zero.rs
@@ -1,3 +1,5 @@
+use core::num::{Saturating, Wrapping};
+
 use crate::boxed::Box;
 
 #[rustc_specialization_trait]
@@ -144,3 +146,17 @@ impl_is_zero_option_of_nonzero!(
     NonZeroUsize,
     NonZeroIsize,
 );
+
+unsafe impl<T: IsZero> IsZero for Wrapping<T> {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        self.0.is_zero()
+    }
+}
+
+unsafe impl<T: IsZero> IsZero for Saturating<T> {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        self.0.is_zero()
+    }
+}
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 1f19b9e59454..d6d986905e6c 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -64,7 +64,7 @@ use core::iter;
 #[cfg(not(no_global_oom_handling))]
 use core::iter::FromIterator;
 use core::marker::PhantomData;
-use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
 use core::ops::{self, Index, IndexMut, Range, RangeBounds};
 use core::ptr::{self, NonNull};
 use core::slice::{self, SliceIndex};
@@ -436,7 +436,7 @@ impl<T> Vec<T> {
     /// an explanation of the difference between length and capacity, see
     /// *[Capacity and reallocation]*.
     ///
-    /// If it is imporant to know the exact allocated capacity of a `Vec`,
+    /// If it is important to know the exact allocated capacity of a `Vec`,
     /// always use the [`capacity`] method after construction.
     ///
     /// For `Vec<T>` where `T` is a zero-sized type, there will be no allocation
@@ -591,7 +591,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// an explanation of the difference between length and capacity, see
     /// *[Capacity and reallocation]*.
     ///
-    /// If it is imporant to know the exact allocated capacity of a `Vec`,
+    /// If it is important to know the exact allocated capacity of a `Vec`,
     /// always use the [`capacity`] method after construction.
     ///
     /// For `Vec<T, A>` where `T` is a zero-sized type, there will be no allocation
@@ -2347,7 +2347,7 @@ impl<T, A: Allocator, const N: usize> Vec<[T; N], A> {
     #[unstable(feature = "slice_flatten", issue = "95629")]
     pub fn into_flattened(self) -> Vec<T, A> {
         let (ptr, len, cap, alloc) = self.into_raw_parts_with_alloc();
-        let (new_len, new_cap) = if mem::size_of::<T>() == 0 {
+        let (new_len, new_cap) = if T::IS_ZST {
             (len.checked_mul(N).expect("vec len overflow"), usize::MAX)
         } else {
             // SAFETY:
@@ -2677,7 +2677,7 @@ impl<T, A: Allocator> IntoIterator for Vec<T, A> {
             let mut me = ManuallyDrop::new(self);
             let alloc = ManuallyDrop::new(ptr::read(me.allocator()));
             let begin = me.as_mut_ptr();
-            let end = if mem::size_of::<T>() == 0 {
+            let end = if T::IS_ZST {
                 begin.wrapping_byte_add(me.len())
             } else {
                 begin.add(me.len()) as *const T
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 490c0d8f76cd..55aced5106c9 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -32,7 +32,7 @@
 #![feature(slice_group_by)]
 #![feature(slice_partition_dedup)]
 #![feature(string_remove_matches)]
-#![feature(const_btree_new)]
+#![feature(const_btree_len)]
 #![feature(const_default_impls)]
 #![feature(const_trait_impl)]
 #![feature(const_str_from_utf8)]
diff --git a/library/backtrace b/library/backtrace
index 4e5a3f72929f..07872f28cd8a 160000
--- a/library/backtrace
+++ b/library/backtrace
@@ -1 +1 @@
-Subproject commit 4e5a3f72929f152752d5659e95bb15c8f6b41eff
+Subproject commit 07872f28cd8a65c3c7428811548dc85f1f2fb05b
diff --git a/library/core/benches/iter.rs b/library/core/benches/iter.rs
index 0abe20e4ca3b..4b40485d207c 100644
--- a/library/core/benches/iter.rs
+++ b/library/core/benches/iter.rs
@@ -363,6 +363,13 @@ fn bench_partial_cmp(b: &mut Bencher) {
     b.iter(|| (0..100000).map(black_box).partial_cmp((0..100000).map(black_box)))
 }
 
+#[bench]
+fn bench_chain_partial_cmp(b: &mut Bencher) {
+    b.iter(|| {
+        (0..50000).chain(50000..100000).map(black_box).partial_cmp((0..100000).map(black_box))
+    })
+}
+
 #[bench]
 fn bench_lt(b: &mut Bencher) {
     b.iter(|| (0..100000).map(black_box).lt((0..100000).map(black_box)))
diff --git a/library/core/src/alloc/layout.rs b/library/core/src/alloc/layout.rs
index f03502429ab2..5bb44b408596 100644
--- a/library/core/src/alloc/layout.rs
+++ b/library/core/src/alloc/layout.rs
@@ -5,7 +5,6 @@
 // Your performance intuition is useless. Run perf.
 
 use crate::cmp;
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 use crate::mem::{self, ValidAlign};
@@ -463,7 +462,6 @@ pub type LayoutErr = LayoutError;
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct LayoutError;
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "alloc_layout", since = "1.28.0")]
 impl Error for LayoutError {}
 
diff --git a/library/core/src/alloc/mod.rs b/library/core/src/alloc/mod.rs
index 94efa76664f6..a4bf6a853a65 100644
--- a/library/core/src/alloc/mod.rs
+++ b/library/core/src/alloc/mod.rs
@@ -21,7 +21,6 @@ pub use self::layout::LayoutErr;
 #[stable(feature = "alloc_layout_error", since = "1.50.0")]
 pub use self::layout::LayoutError;
 
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 use crate::ptr::{self, NonNull};
@@ -34,7 +33,6 @@ use crate::ptr::{self, NonNull};
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct AllocError;
 
-#[cfg(not(bootstrap))]
 #[unstable(
     feature = "allocator_api",
     reason = "the precise API and guarantees it provides may be tweaked.",
@@ -107,6 +105,7 @@ impl fmt::Display for AllocError {
 ///
 /// [*currently allocated*]: #currently-allocated-memory
 #[unstable(feature = "allocator_api", issue = "32838")]
+#[const_trait]
 pub unsafe trait Allocator {
     /// Attempts to allocate a block of memory.
     ///
diff --git a/library/core/src/any.rs b/library/core/src/any.rs
index e54f6c912d59..1a379ecc11c0 100644
--- a/library/core/src/any.rs
+++ b/library/core/src/any.rs
@@ -796,7 +796,7 @@ pub trait Provider {
     /// impl Provider for SomeConcreteType {
     ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
     ///         demand.provide_ref::<str>(&self.field)
-    ///             .provide_value::<i32>(|| self.num_field);
+    ///             .provide_value::<i32>(self.num_field);
     ///     }
     /// }
     /// ```
@@ -881,28 +881,55 @@ impl<'a> Demand<'a> {
     ///
     /// # Examples
     ///
+    /// Provides an `u8`.
+    ///
+    /// ```rust
+    /// #![feature(provide_any)]
+    ///
+    /// use std::any::{Provider, Demand};
+    /// # struct SomeConcreteType { field: u8 }
+    ///
+    /// impl Provider for SomeConcreteType {
+    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
+    ///         demand.provide_value::<u8>(self.field);
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "provide_any", issue = "96024")]
+    pub fn provide_value<T>(&mut self, value: T) -> &mut Self
+    where
+        T: 'static,
+    {
+        self.provide::<tags::Value<T>>(value)
+    }
+
+    /// Provide a value or other type with only static lifetimes computed using a closure.
+    ///
+    /// # Examples
+    ///
     /// Provides a `String` by cloning.
     ///
     /// ```rust
-    /// # #![feature(provide_any)]
+    /// #![feature(provide_any)]
+    ///
     /// use std::any::{Provider, Demand};
     /// # struct SomeConcreteType { field: String }
     ///
     /// impl Provider for SomeConcreteType {
     ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
-    ///         demand.provide_value::<String>(|| self.field.clone());
+    ///         demand.provide_value_with::<String>(|| self.field.clone());
     ///     }
     /// }
     /// ```
     #[unstable(feature = "provide_any", issue = "96024")]
-    pub fn provide_value<T>(&mut self, fulfil: impl FnOnce() -> T) -> &mut Self
+    pub fn provide_value_with<T>(&mut self, fulfil: impl FnOnce() -> T) -> &mut Self
     where
         T: 'static,
     {
         self.provide_with::<tags::Value<T>>(fulfil)
     }
 
-    /// Provide a reference, note that the referee type must be bounded by `'static`,
+    /// Provide a reference. The referee type must be bounded by `'static`,
     /// but may be unsized.
     ///
     /// # Examples
@@ -910,7 +937,8 @@ impl<'a> Demand<'a> {
     /// Provides a reference to a field as a `&str`.
     ///
     /// ```rust
-    /// # #![feature(provide_any)]
+    /// #![feature(provide_any)]
+    ///
     /// use std::any::{Provider, Demand};
     /// # struct SomeConcreteType { field: String }
     ///
@@ -925,6 +953,40 @@ impl<'a> Demand<'a> {
         self.provide::<tags::Ref<tags::MaybeSizedValue<T>>>(value)
     }
 
+    /// Provide a reference computed using a closure. The referee type
+    /// must be bounded by `'static`, but may be unsized.
+    ///
+    /// # Examples
+    ///
+    /// Provides a reference to a field as a `&str`.
+    ///
+    /// ```rust
+    /// #![feature(provide_any)]
+    ///
+    /// use std::any::{Provider, Demand};
+    /// # struct SomeConcreteType { business: String, party: String }
+    /// # fn today_is_a_weekday() -> bool { true }
+    ///
+    /// impl Provider for SomeConcreteType {
+    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
+    ///         demand.provide_ref_with::<str>(|| {
+    ///             if today_is_a_weekday() {
+    ///                 &self.business
+    ///             } else {
+    ///                 &self.party
+    ///             }
+    ///         });
+    ///     }
+    /// }
+    /// ```
+    #[unstable(feature = "provide_any", issue = "96024")]
+    pub fn provide_ref_with<T: ?Sized + 'static>(
+        &mut self,
+        fulfil: impl FnOnce() -> &'a T,
+    ) -> &mut Self {
+        self.provide_with::<tags::Ref<tags::MaybeSizedValue<T>>>(fulfil)
+    }
+
     /// Provide a value with the given `Type` tag.
     fn provide<I>(&mut self, value: I::Reified) -> &mut Self
     where
@@ -946,6 +1008,156 @@ impl<'a> Demand<'a> {
         }
         self
     }
+
+    /// Check if the `Demand` would be satisfied if provided with a
+    /// value of the specified type. If the type does not match or has
+    /// already been provided, returns false.
+    ///
+    /// # Examples
+    ///
+    /// Check if an `u8` still needs to be provided and then provides
+    /// it.
+    ///
+    /// ```rust
+    /// #![feature(provide_any)]
+    ///
+    /// use std::any::{Provider, Demand};
+    ///
+    /// struct Parent(Option<u8>);
+    ///
+    /// impl Provider for Parent {
+    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
+    ///         if let Some(v) = self.0 {
+    ///             demand.provide_value::<u8>(v);
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// struct Child {
+    ///     parent: Parent,
+    /// }
+    ///
+    /// impl Child {
+    ///     // Pretend that this takes a lot of resources to evaluate.
+    ///     fn an_expensive_computation(&self) -> Option<u8> {
+    ///         Some(99)
+    ///     }
+    /// }
+    ///
+    /// impl Provider for Child {
+    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
+    ///         // In general, we don't know if this call will provide
+    ///         // an `u8` value or not...
+    ///         self.parent.provide(demand);
+    ///
+    ///         // ...so we check to see if the `u8` is needed before
+    ///         // we run our expensive computation.
+    ///         if demand.would_be_satisfied_by_value_of::<u8>() {
+    ///             if let Some(v) = self.an_expensive_computation() {
+    ///                 demand.provide_value::<u8>(v);
+    ///             }
+    ///         }
+    ///
+    ///         // The demand will be satisfied now, regardless of if
+    ///         // the parent provided the value or we did.
+    ///         assert!(!demand.would_be_satisfied_by_value_of::<u8>());
+    ///     }
+    /// }
+    ///
+    /// let parent = Parent(Some(42));
+    /// let child = Child { parent };
+    /// assert_eq!(Some(42), std::any::request_value::<u8>(&child));
+    ///
+    /// let parent = Parent(None);
+    /// let child = Child { parent };
+    /// assert_eq!(Some(99), std::any::request_value::<u8>(&child));
+    /// ```
+    #[unstable(feature = "provide_any", issue = "96024")]
+    pub fn would_be_satisfied_by_value_of<T>(&self) -> bool
+    where
+        T: 'static,
+    {
+        self.would_be_satisfied_by::<tags::Value<T>>()
+    }
+
+    /// Check if the `Demand` would be satisfied if provided with a
+    /// reference to a value of the specified type. If the type does
+    /// not match or has already been provided, returns false.
+    ///
+    /// # Examples
+    ///
+    /// Check if a `&str` still needs to be provided and then provides
+    /// it.
+    ///
+    /// ```rust
+    /// #![feature(provide_any)]
+    ///
+    /// use std::any::{Provider, Demand};
+    ///
+    /// struct Parent(Option<String>);
+    ///
+    /// impl Provider for Parent {
+    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
+    ///         if let Some(v) = &self.0 {
+    ///             demand.provide_ref::<str>(v);
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// struct Child {
+    ///     parent: Parent,
+    ///     name: String,
+    /// }
+    ///
+    /// impl Child {
+    ///     // Pretend that this takes a lot of resources to evaluate.
+    ///     fn an_expensive_computation(&self) -> Option<&str> {
+    ///         Some(&self.name)
+    ///     }
+    /// }
+    ///
+    /// impl Provider for Child {
+    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
+    ///         // In general, we don't know if this call will provide
+    ///         // a `str` reference or not...
+    ///         self.parent.provide(demand);
+    ///
+    ///         // ...so we check to see if the `&str` is needed before
+    ///         // we run our expensive computation.
+    ///         if demand.would_be_satisfied_by_ref_of::<str>() {
+    ///             if let Some(v) = self.an_expensive_computation() {
+    ///                 demand.provide_ref::<str>(v);
+    ///             }
+    ///         }
+    ///
+    ///         // The demand will be satisfied now, regardless of if
+    ///         // the parent provided the reference or we did.
+    ///         assert!(!demand.would_be_satisfied_by_ref_of::<str>());
+    ///     }
+    /// }
+    ///
+    /// let parent = Parent(Some("parent".into()));
+    /// let child = Child { parent, name: "child".into() };
+    /// assert_eq!(Some("parent"), std::any::request_ref::<str>(&child));
+    ///
+    /// let parent = Parent(None);
+    /// let child = Child { parent, name: "child".into() };
+    /// assert_eq!(Some("child"), std::any::request_ref::<str>(&child));
+    /// ```
+    #[unstable(feature = "provide_any", issue = "96024")]
+    pub fn would_be_satisfied_by_ref_of<T>(&self) -> bool
+    where
+        T: ?Sized + 'static,
+    {
+        self.would_be_satisfied_by::<tags::Ref<tags::MaybeSizedValue<T>>>()
+    }
+
+    fn would_be_satisfied_by<I>(&self) -> bool
+    where
+        I: tags::Type<'a>,
+    {
+        matches!(self.0.downcast::<I>(), Some(TaggedOption(None)))
+    }
 }
 
 #[unstable(feature = "provide_any", issue = "96024")]
@@ -1050,6 +1262,21 @@ impl<'a> dyn Erased<'a> + 'a {
     /// Returns some reference to the dynamic value if it is tagged with `I`,
     /// or `None` otherwise.
     #[inline]
+    fn downcast<I>(&self) -> Option<&TaggedOption<'a, I>>
+    where
+        I: tags::Type<'a>,
+    {
+        if self.tag_id() == TypeId::of::<I>() {
+            // SAFETY: Just checked whether we're pointing to an I.
+            Some(unsafe { &*(self as *const Self).cast::<TaggedOption<'a, I>>() })
+        } else {
+            None
+        }
+    }
+
+    /// Returns some mutable reference to the dynamic value if it is tagged with `I`,
+    /// or `None` otherwise.
+    #[inline]
     fn downcast_mut<I>(&mut self) -> Option<&mut TaggedOption<'a, I>>
     where
         I: tags::Type<'a>,
diff --git a/library/core/src/array/iter.rs b/library/core/src/array/iter.rs
index f4885ed9ffbb..b3b260400671 100644
--- a/library/core/src/array/iter.rs
+++ b/library/core/src/array/iter.rs
@@ -1,10 +1,10 @@
 //! Defines the `IntoIter` owned iterator for arrays.
 
 use crate::{
-    cmp, fmt,
+    fmt,
     iter::{self, ExactSizeIterator, FusedIterator, TrustedLen},
     mem::{self, MaybeUninit},
-    ops::Range,
+    ops::{IndexRange, Range},
     ptr,
 };
 
@@ -29,9 +29,10 @@ pub struct IntoIter<T, const N: usize> {
     /// The elements in `data` that have not been yielded yet.
     ///
     /// Invariants:
-    /// - `alive.start <= alive.end`
     /// - `alive.end <= N`
-    alive: Range<usize>,
+    ///
+    /// (And the `IndexRange` type requires `alive.start <= alive.end`.)
+    alive: IndexRange,
 }
 
 // Note: the `#[rustc_skip_array_during_method_dispatch]` on `trait IntoIterator`
@@ -69,7 +70,7 @@ impl<T, const N: usize> IntoIterator for [T; N] {
         // Until then, we can use `mem::transmute_copy` to create a bitwise copy
         // as a different type, then forget `array` so that it is not dropped.
         unsafe {
-            let iter = IntoIter { data: mem::transmute_copy(&self), alive: 0..N };
+            let iter = IntoIter { data: mem::transmute_copy(&self), alive: IndexRange::zero_to(N) };
             mem::forget(self);
             iter
         }
@@ -147,7 +148,9 @@ impl<T, const N: usize> IntoIter<T, N> {
         buffer: [MaybeUninit<T>; N],
         initialized: Range<usize>,
     ) -> Self {
-        Self { data: buffer, alive: initialized }
+        // SAFETY: one of our safety conditions is that the range is canonical.
+        let alive = unsafe { IndexRange::new_unchecked(initialized.start, initialized.end) };
+        Self { data: buffer, alive }
     }
 
     /// Creates an iterator over `T` which returns no elements.
@@ -283,16 +286,11 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> {
     }
 
     fn advance_by(&mut self, n: usize) -> Result<(), usize> {
-        let len = self.len();
+        let original_len = self.len();
 
-        // The number of elements to drop.  Always in-bounds by construction.
-        let delta = cmp::min(n, len);
-
-        let range_to_drop = self.alive.start..(self.alive.start + delta);
-
-        // Moving the start marks them as conceptually "dropped", so if anything
-        // goes bad then our drop impl won't double-free them.
-        self.alive.start += delta;
+        // This also moves the start, which marks them as conceptually "dropped",
+        // so if anything goes bad then our drop impl won't double-free them.
+        let range_to_drop = self.alive.take_prefix(n);
 
         // SAFETY: These elements are currently initialized, so it's fine to drop them.
         unsafe {
@@ -300,7 +298,7 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> {
             ptr::drop_in_place(MaybeUninit::slice_assume_init_mut(slice));
         }
 
-        if n > len { Err(len) } else { Ok(()) }
+        if n > original_len { Err(original_len) } else { Ok(()) }
     }
 }
 
@@ -338,16 +336,11 @@ impl<T, const N: usize> DoubleEndedIterator for IntoIter<T, N> {
     }
 
     fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
-        let len = self.len();
+        let original_len = self.len();
 
-        // The number of elements to drop.  Always in-bounds by construction.
-        let delta = cmp::min(n, len);
-
-        let range_to_drop = (self.alive.end - delta)..self.alive.end;
-
-        // Moving the end marks them as conceptually "dropped", so if anything
-        // goes bad then our drop impl won't double-free them.
-        self.alive.end -= delta;
+        // This also moves the end, which marks them as conceptually "dropped",
+        // so if anything goes bad then our drop impl won't double-free them.
+        let range_to_drop = self.alive.take_suffix(n);
 
         // SAFETY: These elements are currently initialized, so it's fine to drop them.
         unsafe {
@@ -355,7 +348,7 @@ impl<T, const N: usize> DoubleEndedIterator for IntoIter<T, N> {
             ptr::drop_in_place(MaybeUninit::slice_assume_init_mut(slice));
         }
 
-        if n > len { Err(len) } else { Ok(()) }
+        if n > original_len { Err(original_len) } else { Ok(()) }
     }
 }
 
@@ -372,9 +365,7 @@ impl<T, const N: usize> Drop for IntoIter<T, N> {
 #[stable(feature = "array_value_iter_impls", since = "1.40.0")]
 impl<T, const N: usize> ExactSizeIterator for IntoIter<T, N> {
     fn len(&self) -> usize {
-        // Will never underflow due to the invariant `alive.start <=
-        // alive.end`.
-        self.alive.end - self.alive.start
+        self.alive.len()
     }
     fn is_empty(&self) -> bool {
         self.alive.is_empty()
@@ -396,14 +387,15 @@ impl<T: Clone, const N: usize> Clone for IntoIter<T, N> {
     fn clone(&self) -> Self {
         // Note, we don't really need to match the exact same alive range, so
         // we can just clone into offset 0 regardless of where `self` is.
-        let mut new = Self { data: MaybeUninit::uninit_array(), alive: 0..0 };
+        let mut new = Self { data: MaybeUninit::uninit_array(), alive: IndexRange::zero_to(0) };
 
         // Clone all alive elements.
         for (src, dst) in iter::zip(self.as_slice(), &mut new.data) {
             // Write a clone into the new array, then update its alive range.
             // If cloning panics, we'll correctly drop the previous items.
             dst.write(src.clone());
-            new.alive.end += 1;
+            // This addition cannot overflow as we're iterating a slice
+            new.alive = IndexRange::zero_to(new.alive.end() + 1);
         }
 
         new
diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index 9effb3790160..b82bbf2267a9 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -7,7 +7,6 @@
 use crate::borrow::{Borrow, BorrowMut};
 use crate::cmp::Ordering;
 use crate::convert::{Infallible, TryFrom};
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 use crate::hash::{self, Hash};
@@ -121,7 +120,6 @@ impl fmt::Display for TryFromSliceError {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "try_from", since = "1.34.0")]
 impl Error for TryFromSliceError {
     #[allow(deprecated)]
@@ -184,6 +182,18 @@ impl<T, const N: usize> const BorrowMut<[T]> for [T; N] {
     }
 }
 
+/// Tries to create an array `[T; N]` by copying from a slice `&[T]`. Succeeds if
+/// `slice.len() == N`.
+///
+/// ```
+/// let bytes: [u8; 3] = [1, 0, 2];
+///
+/// let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&bytes[0..2]).unwrap();
+/// assert_eq!(1, u16::from_le_bytes(bytes_head));
+///
+/// let bytes_tail: [u8; 2] = bytes[1..3].try_into().unwrap();
+/// assert_eq!(512, u16::from_le_bytes(bytes_tail));
+/// ```
 #[stable(feature = "try_from", since = "1.34.0")]
 impl<T, const N: usize> TryFrom<&[T]> for [T; N]
 where
@@ -196,6 +206,18 @@ where
     }
 }
 
+/// Tries to create an array `[T; N]` by copying from a mutable slice `&mut [T]`.
+/// Succeeds if `slice.len() == N`.
+///
+/// ```
+/// let mut bytes: [u8; 3] = [1, 0, 2];
+///
+/// let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
+/// assert_eq!(1, u16::from_le_bytes(bytes_head));
+///
+/// let bytes_tail: [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
+/// assert_eq!(512, u16::from_le_bytes(bytes_tail));
+/// ```
 #[stable(feature = "try_from_mut_slice_to_array", since = "1.59.0")]
 impl<T, const N: usize> TryFrom<&mut [T]> for [T; N]
 where
@@ -208,6 +230,18 @@ where
     }
 }
 
+/// Tries to create an array ref `&[T; N]` from a slice ref `&[T]`. Succeeds if
+/// `slice.len() == N`.
+///
+/// ```
+/// let bytes: [u8; 3] = [1, 0, 2];
+///
+/// let bytes_head: &[u8; 2] = <&[u8; 2]>::try_from(&bytes[0..2]).unwrap();
+/// assert_eq!(1, u16::from_le_bytes(*bytes_head));
+///
+/// let bytes_tail: &[u8; 2] = bytes[1..3].try_into().unwrap();
+/// assert_eq!(512, u16::from_le_bytes(*bytes_tail));
+/// ```
 #[stable(feature = "try_from", since = "1.34.0")]
 impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N] {
     type Error = TryFromSliceError;
@@ -223,6 +257,18 @@ impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N] {
     }
 }
 
+/// Tries to create a mutable array ref `&mut [T; N]` from a mutable slice ref
+/// `&mut [T]`. Succeeds if `slice.len() == N`.
+///
+/// ```
+/// let mut bytes: [u8; 3] = [1, 0, 2];
+///
+/// let bytes_head: &mut [u8; 2] = <&mut [u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
+/// assert_eq!(1, u16::from_le_bytes(*bytes_head));
+///
+/// let bytes_tail: &mut [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
+/// assert_eq!(512, u16::from_le_bytes(*bytes_tail));
+/// ```
 #[stable(feature = "try_from", since = "1.34.0")]
 impl<'a, T, const N: usize> TryFrom<&'a mut [T]> for &'a mut [T; N] {
     type Error = TryFromSliceError;
@@ -386,7 +432,8 @@ impl<T: Copy> SpecArrayClone for T {
 macro_rules! array_impl_default {
     {$n:expr, $t:ident $($ts:ident)*} => {
         #[stable(since = "1.4.0", feature = "array_default")]
-        impl<T> Default for [T; $n] where T: Default {
+        #[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+        impl<T> const Default for [T; $n] where T: ~const Default {
             fn default() -> [T; $n] {
                 [$t::default(), $($ts::default()),*]
             }
diff --git a/library/core/src/bool.rs b/library/core/src/bool.rs
index f7a8aa0d9215..db1c505ba385 100644
--- a/library/core/src/bool.rs
+++ b/library/core/src/bool.rs
@@ -6,12 +6,30 @@ impl bool {
     /// Returns `Some(t)` if the `bool` is [`true`](../std/keyword.true.html),
     /// or `None` otherwise.
     ///
+    /// Arguments passed to `then_some` are eagerly evaluated; if you are
+    /// passing the result of a function call, it is recommended to use
+    /// [`then`], which is lazily evaluated.
+    ///
+    /// [`then`]: bool::then
+    ///
     /// # Examples
     ///
     /// ```
     /// assert_eq!(false.then_some(0), None);
     /// assert_eq!(true.then_some(0), Some(0));
     /// ```
+    ///
+    /// ```
+    /// let mut a = 0;
+    /// let mut function_with_side_effects = || { a += 1; };
+    ///
+    /// true.then_some(function_with_side_effects());
+    /// false.then_some(function_with_side_effects());
+    ///
+    /// // `a` is incremented twice because the value passed to `then_some` is
+    /// // evaluated eagerly.
+    /// assert_eq!(a, 2);
+    /// ```
     #[stable(feature = "bool_to_option", since = "1.62.0")]
     #[rustc_const_unstable(feature = "const_bool_to_option", issue = "91917")]
     #[inline]
@@ -31,6 +49,17 @@ impl bool {
     /// assert_eq!(false.then(|| 0), None);
     /// assert_eq!(true.then(|| 0), Some(0));
     /// ```
+    ///
+    /// ```
+    /// let mut a = 0;
+    ///
+    /// true.then(|| { a += 1; });
+    /// false.then(|| { a += 1; });
+    ///
+    /// // `a` is incremented once because the closure is evaluated lazily by
+    /// // `then`.
+    /// assert_eq!(a, 1);
+    /// ```
     #[stable(feature = "lazy_bool_to_option", since = "1.50.0")]
     #[rustc_const_unstable(feature = "const_bool_to_option", issue = "91917")]
     #[inline]
diff --git a/library/core/src/borrow.rs b/library/core/src/borrow.rs
index 8378611eb18c..fdd56cb4eaa8 100644
--- a/library/core/src/borrow.rs
+++ b/library/core/src/borrow.rs
@@ -154,6 +154,7 @@
 /// [`String`]: ../../std/string/struct.String.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Borrow"]
+#[const_trait]
 pub trait Borrow<Borrowed: ?Sized> {
     /// Immutably borrows from an owned value.
     ///
@@ -184,6 +185,7 @@ pub trait Borrow<Borrowed: ?Sized> {
 /// an underlying type by providing a mutable reference. See [`Borrow<T>`]
 /// for more information on borrowing as another type.
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait BorrowMut<Borrowed: ?Sized>: Borrow<Borrowed> {
     /// Mutably borrows from an owned value.
     ///
diff --git a/library/core/src/cell.rs b/library/core/src/cell.rs
index fb4454c94cb3..1abbb39497a0 100644
--- a/library/core/src/cell.rs
+++ b/library/core/src/cell.rs
@@ -1021,15 +1021,18 @@ impl<T: ?Sized> RefCell<T> {
 
     /// Returns a mutable reference to the underlying data.
     ///
-    /// This call borrows `RefCell` mutably (at compile-time) so there is no
-    /// need for dynamic checks.
+    /// Since this method borrows `RefCell` mutably, it is statically guaranteed
+    /// that no borrows to the underlying data exist. The dynamic checks inherent
+    /// in [`borrow_mut`] and most other methods of `RefCell` are therefor
+    /// unnecessary.
     ///
-    /// However be cautious: this method expects `self` to be mutable, which is
-    /// generally not the case when using a `RefCell`. Take a look at the
-    /// [`borrow_mut`] method instead if `self` isn't mutable.
+    /// This method can only be called if `RefCell` can be mutably borrowed,
+    /// which in general is only the case directly after the `RefCell` has
+    /// been created. In these situations, skipping the aforementioned dynamic
+    /// borrowing checks may yield better ergonomics and runtime-performance.
     ///
-    /// Also, please be aware that this method is only for special circumstances and is usually
-    /// not what you want. In case of doubt, use [`borrow_mut`] instead.
+    /// In most situations where `RefCell` is used, it can't be borrowed mutably.
+    /// Use [`borrow_mut`] to get mutable access to the underlying data then.
     ///
     /// [`borrow_mut`]: RefCell::borrow_mut()
     ///
diff --git a/library/core/src/char/decode.rs b/library/core/src/char/decode.rs
index dc8ea66cc6d0..11f1c30f6d55 100644
--- a/library/core/src/char/decode.rs
+++ b/library/core/src/char/decode.rs
@@ -1,6 +1,5 @@
 //! UTF-8 and UTF-16 decoding iterators
 
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 
@@ -124,7 +123,6 @@ impl fmt::Display for DecodeUtf16Error {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "decode_utf16", since = "1.9.0")]
 impl Error for DecodeUtf16Error {
     #[allow(deprecated)]
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs
index 2433139a592b..b7a63b7c6756 100644
--- a/library/core/src/char/methods.rs
+++ b/library/core/src/char/methods.rs
@@ -746,10 +746,19 @@ impl char {
     /// assert!(!'中'.is_lowercase());
     /// assert!(!' '.is_lowercase());
     /// ```
+    ///
+    /// In a const context:
+    ///
+    /// ```
+    /// #![feature(const_unicode_case_lookup)]
+    /// const CAPITAL_DELTA_IS_LOWERCASE: bool = 'Δ'.is_lowercase();
+    /// assert!(!CAPITAL_DELTA_IS_LOWERCASE);
+    /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]
     #[inline]
-    pub fn is_lowercase(self) -> bool {
+    pub const fn is_lowercase(self) -> bool {
         match self {
             'a'..='z' => true,
             c => c > '\x7f' && unicode::Lowercase(c),
@@ -779,10 +788,19 @@ impl char {
     /// assert!(!'中'.is_uppercase());
     /// assert!(!' '.is_uppercase());
     /// ```
+    ///
+    /// In a const context:
+    ///
+    /// ```
+    /// #![feature(const_unicode_case_lookup)]
+    /// const CAPITAL_DELTA_IS_UPPERCASE: bool = 'Δ'.is_uppercase();
+    /// assert!(CAPITAL_DELTA_IS_UPPERCASE);
+    /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]
     #[inline]
-    pub fn is_uppercase(self) -> bool {
+    pub const fn is_uppercase(self) -> bool {
         match self {
             'A'..='Z' => true,
             c => c > '\x7f' && unicode::Uppercase(c),
diff --git a/library/core/src/char/mod.rs b/library/core/src/char/mod.rs
index 72d63ac4b4b4..b34a7121631c 100644
--- a/library/core/src/char/mod.rs
+++ b/library/core/src/char/mod.rs
@@ -38,7 +38,6 @@ pub use self::methods::encode_utf16_raw;
 #[unstable(feature = "char_internals", reason = "exposed only for libstd", issue = "none")]
 pub use self::methods::encode_utf8_raw;
 
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt::{self, Write};
 use crate::iter::FusedIterator;
@@ -587,6 +586,5 @@ impl fmt::Display for TryFromCharError {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "u8_from_char", since = "1.59.0")]
 impl Error for TryFromCharError {}
diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index 8a30bb674506..f0fa2e1d2c19 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -22,7 +22,9 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
+use crate::const_closure::ConstFnMutClosure;
 use crate::marker::Destruct;
+use crate::marker::StructuralPartialEq;
 
 use self::Ordering::*;
 
@@ -203,20 +205,10 @@ use self::Ordering::*;
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "==")]
 #[doc(alias = "!=")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} == {Rhs}`"
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} == {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    message = "can't compare `{Self}` with `{Rhs}`",
+    label = "no implementation for `{Self} == {Rhs}`",
+    append_const_msg
 )]
 #[const_trait]
 #[rustc_diagnostic_item = "PartialEq"]
@@ -338,7 +330,7 @@ pub struct AssertParamIsEq<T: Eq + ?Sized> {
 /// let result = 2.cmp(&1);
 /// assert_eq!(Ordering::Greater, result);
 /// ```
-#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+#[derive(Clone, Copy, Eq, Debug, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[repr(i8)]
 pub enum Ordering {
@@ -884,6 +876,18 @@ pub macro Ord($item:item) {
     /* compiler built-in */
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl StructuralPartialEq for Ordering {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+impl const PartialEq for Ordering {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        (*self as i32).eq(&(*other as i32))
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
 impl const Ord for Ordering {
@@ -1063,20 +1067,10 @@ impl const PartialOrd for Ordering {
 #[doc(alias = "<")]
 #[doc(alias = "<=")]
 #[doc(alias = ">=")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    message = "can't compare `{Self}` with `{Rhs}`",
+    label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
+    append_const_msg
 )]
 #[const_trait]
 #[rustc_diagnostic_item = "PartialOrd"]
@@ -1229,7 +1223,12 @@ pub const fn min<T: ~const Ord + ~const Destruct>(v1: T, v2: T) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn min_by<T, F: ~const FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+{
     match compare(&v1, &v2) {
         Ordering::Less | Ordering::Equal => v1,
         Ordering::Greater => v2,
@@ -1251,8 +1250,24 @@ pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn min_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
-    min_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2)))
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn min_by_key<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(v1: T, v2: T, mut f: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+    K: ~const Destruct,
+{
+    const fn imp<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(
+        f: &mut F,
+        (v1, v2): (&T, &T),
+    ) -> Ordering
+    where
+        T: ~const Destruct,
+        K: ~const Destruct,
+    {
+        f(v1).cmp(&f(v2))
+    }
+    min_by(v1, v2, ConstFnMutClosure::new(&mut f, imp))
 }
 
 /// Compares and returns the maximum of two values.
@@ -1293,7 +1308,12 @@ pub const fn max<T: ~const Ord + ~const Destruct>(v1: T, v2: T) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn max_by<T, F: ~const FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+{
     match compare(&v1, &v2) {
         Ordering::Less | Ordering::Equal => v2,
         Ordering::Greater => v1,
@@ -1315,8 +1335,24 @@ pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn max_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
-    max_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2)))
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn max_by_key<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(v1: T, v2: T, mut f: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+    K: ~const Destruct,
+{
+    const fn imp<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(
+        f: &mut F,
+        (v1, v2): (&T, &T),
+    ) -> Ordering
+    where
+        T: ~const Destruct,
+        K: ~const Destruct,
+    {
+        f(v1).cmp(&f(v2))
+    }
+    max_by(v1, v2, ConstFnMutClosure::new(&mut f, imp))
 }
 
 // Implementation of PartialEq, Eq, PartialOrd and Ord for primitive types
diff --git a/library/core/src/const_closure.rs b/library/core/src/const_closure.rs
new file mode 100644
index 000000000000..d2e80e8e7e5d
--- /dev/null
+++ b/library/core/src/const_closure.rs
@@ -0,0 +1,63 @@
+use crate::marker::Destruct;
+
+/// Struct representing a closure with mutably borrowed data.
+///
+/// Example:
+/// ```no_build
+/// #![feature(const_mut_refs)]
+/// use crate::const_closure::ConstFnMutClosure;
+/// const fn imp(state: &mut i32, (arg,): (i32,)) -> i32 {
+///   *state += arg;
+///   *state
+/// }
+/// let mut i = 5;
+/// let mut cl = ConstFnMutClosure::new(&mut i, imp);
+///
+/// assert!(7 == cl(2));
+/// assert!(8 == cl(1));
+/// ```
+pub(crate) struct ConstFnMutClosure<'a, CapturedData: ?Sized, Function> {
+    data: &'a mut CapturedData,
+    func: Function,
+}
+
+impl<'a, CapturedData: ?Sized, Function> ConstFnMutClosure<'a, CapturedData, Function> {
+    /// Function for creating a new closure.
+    ///
+    /// `data` is the a mutable borrow of data that is captured from the environment.
+    ///
+    /// `func` is the function of the closure, it gets the data and a tuple of the arguments closure
+    ///   and return the return value of the closure.
+    pub(crate) const fn new<ClosureArguments, ClosureReturnValue>(
+        data: &'a mut CapturedData,
+        func: Function,
+    ) -> Self
+    where
+        Function: ~const Fn(&mut CapturedData, ClosureArguments) -> ClosureReturnValue,
+    {
+        Self { data, func }
+    }
+}
+
+impl<'a, CapturedData: ?Sized, ClosureArguments, Function, ClosureReturnValue> const
+    FnOnce<ClosureArguments> for ConstFnMutClosure<'a, CapturedData, Function>
+where
+    Function:
+        ~const Fn(&mut CapturedData, ClosureArguments) -> ClosureReturnValue + ~const Destruct,
+{
+    type Output = ClosureReturnValue;
+
+    extern "rust-call" fn call_once(mut self, args: ClosureArguments) -> Self::Output {
+        self.call_mut(args)
+    }
+}
+
+impl<'a, CapturedData: ?Sized, ClosureArguments, Function, ClosureReturnValue> const
+    FnMut<ClosureArguments> for ConstFnMutClosure<'a, CapturedData, Function>
+where
+    Function: ~const Fn(&mut CapturedData, ClosureArguments) -> ClosureReturnValue,
+{
+    extern "rust-call" fn call_mut(&mut self, args: ClosureArguments) -> Self::Output {
+        (self.func)(self.data, args)
+    }
+}
diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index 5bddfd1a413e..c42adda8da54 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -34,7 +34,6 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 use crate::hash::{Hash, Hasher};
@@ -155,6 +154,7 @@ pub const fn identity<T>(x: T) -> T {
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "AsRef")]
+#[const_trait]
 pub trait AsRef<T: ?Sized> {
     /// Converts this type into a shared reference of the (usually inferred) input type.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -197,6 +197,7 @@ pub trait AsRef<T: ?Sized> {
 /// [`Box<T>`]: ../../std/boxed/struct.Box.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "AsMut")]
+#[const_trait]
 pub trait AsMut<T: ?Sized> {
     /// Converts this type into a mutable reference of the (usually inferred) input type.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -273,6 +274,7 @@ pub trait AsMut<T: ?Sized> {
 /// [`Vec`]: ../../std/vec/struct.Vec.html
 #[rustc_diagnostic_item = "Into"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait Into<T>: Sized {
     /// Converts this type into the (usually inferred) input type.
     #[must_use]
@@ -368,6 +370,7 @@ pub trait Into<T>: Sized {
     all(_Self = "&str", T = "std::string::String"),
     note = "to coerce a `{T}` into a `{Self}`, use `&*` as a prefix",
 ))]
+#[const_trait]
 pub trait From<T>: Sized {
     /// Converts to this type from the input type.
     #[lang = "from"]
@@ -392,6 +395,7 @@ pub trait From<T>: Sized {
 /// [`Into`], see there for details.
 #[rustc_diagnostic_item = "TryInto"]
 #[stable(feature = "try_from", since = "1.34.0")]
+#[const_trait]
 pub trait TryInto<T>: Sized {
     /// The type returned in the event of a conversion error.
     #[stable(feature = "try_from", since = "1.34.0")]
@@ -468,6 +472,7 @@ pub trait TryInto<T>: Sized {
 /// [`try_from`]: TryFrom::try_from
 #[rustc_diagnostic_item = "TryFrom"]
 #[stable(feature = "try_from", since = "1.34.0")]
+#[const_trait]
 pub trait TryFrom<T>: Sized {
     /// The type returned in the event of a conversion error.
     #[stable(feature = "try_from", since = "1.34.0")]
@@ -558,6 +563,7 @@ where
 #[rustc_const_unstable(feature = "const_convert", issue = "88674")]
 impl<T> const From<T> for T {
     /// Returns the argument unchanged.
+    #[inline(always)]
     fn from(t: T) -> T {
         t
     }
@@ -717,7 +723,6 @@ impl fmt::Display for Infallible {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "str_parse_error2", since = "1.8.0")]
 impl Error for Infallible {
     fn description(&self) -> &str {
diff --git a/library/core/src/default.rs b/library/core/src/default.rs
index b53cd6074b53..a5b4e965552c 100644
--- a/library/core/src/default.rs
+++ b/library/core/src/default.rs
@@ -99,6 +99,7 @@
 /// ```
 #[cfg_attr(not(test), rustc_diagnostic_item = "Default")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait Default: Sized {
     /// Returns the "default value" for a type.
     ///
diff --git a/library/core/src/ffi/c_double.md b/library/core/src/ffi/c_double.md
index 57f4534829ec..d49e29b6e6e7 100644
--- a/library/core/src/ffi/c_double.md
+++ b/library/core/src/ffi/c_double.md
@@ -1,6 +1,6 @@
 Equivalent to C's `double` type.
 
-This type will almost always be [`f64`], which is guaranteed to be an [IEEE-754 double-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number with at least the precision of a [`float`], and it may be `f32` or something entirely different from the IEEE-754 standard.
+This type will almost always be [`f64`], which is guaranteed to be an [IEEE 754 double-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number with at least the precision of a [`float`], and it may be `f32` or something entirely different from the IEEE-754 standard.
 
-[IEEE-754 double-precision float]: https://en.wikipedia.org/wiki/IEEE_754
+[IEEE 754 double-precision float]: https://en.wikipedia.org/wiki/IEEE_754
 [`float`]: c_float
diff --git a/library/core/src/ffi/c_float.md b/library/core/src/ffi/c_float.md
index 61e2abc05189..36374ef43618 100644
--- a/library/core/src/ffi/c_float.md
+++ b/library/core/src/ffi/c_float.md
@@ -1,5 +1,5 @@
 Equivalent to C's `float` type.
 
-This type will almost always be [`f32`], which is guaranteed to be an [IEEE-754 single-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number, and it may have less precision than `f32` or not follow the IEEE-754 standard at all.
+This type will almost always be [`f32`], which is guaranteed to be an [IEEE 754 single-precision float] in Rust. That said, the standard technically only guarantees that it be a floating-point number, and it may have less precision than `f32` or not follow the IEEE-754 standard at all.
 
-[IEEE-754 single-precision float]: https://en.wikipedia.org/wiki/IEEE_754
+[IEEE 754 single-precision float]: https://en.wikipedia.org/wiki/IEEE_754
diff --git a/library/core/src/ffi/c_str.rs b/library/core/src/ffi/c_str.rs
index d8b8ac4d8710..21f80ec025a8 100644
--- a/library/core/src/ffi/c_str.rs
+++ b/library/core/src/ffi/c_str.rs
@@ -1,7 +1,6 @@
-use crate::ascii;
 use crate::cmp::Ordering;
 use crate::ffi::c_char;
-use crate::fmt::{self, Write};
+use crate::fmt;
 use crate::intrinsics;
 use crate::ops;
 use crate::slice;
@@ -121,10 +120,10 @@ enum FromBytesWithNulErrorKind {
 }
 
 impl FromBytesWithNulError {
-    fn interior_nul(pos: usize) -> FromBytesWithNulError {
+    const fn interior_nul(pos: usize) -> FromBytesWithNulError {
         FromBytesWithNulError { kind: FromBytesWithNulErrorKind::InteriorNul(pos) }
     }
-    fn not_nul_terminated() -> FromBytesWithNulError {
+    const fn not_nul_terminated() -> FromBytesWithNulError {
         FromBytesWithNulError { kind: FromBytesWithNulErrorKind::NotNulTerminated }
     }
 
@@ -161,11 +160,7 @@ impl fmt::Display for FromBytesUntilNulError {
 #[stable(feature = "cstr_debug", since = "1.3.0")]
 impl fmt::Debug for CStr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "\"")?;
-        for byte in self.to_bytes().iter().flat_map(|&b| ascii::escape_default(b)) {
-            f.write_char(byte as char)?;
-        }
-        write!(f, "\"")
+        write!(f, "\"{}\"", self.to_bytes().escape_ascii())
     }
 }
 
@@ -299,7 +294,8 @@ impl CStr {
     /// ```
     ///
     #[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")]
-    pub fn from_bytes_until_nul(bytes: &[u8]) -> Result<&CStr, FromBytesUntilNulError> {
+    #[rustc_const_unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")]
+    pub const fn from_bytes_until_nul(bytes: &[u8]) -> Result<&CStr, FromBytesUntilNulError> {
         let nul_pos = memchr::memchr(0, bytes);
         match nul_pos {
             Some(nul_pos) => {
@@ -348,7 +344,8 @@ impl CStr {
     /// assert!(cstr.is_err());
     /// ```
     #[stable(feature = "cstr_from_bytes", since = "1.10.0")]
-    pub fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, FromBytesWithNulError> {
+    #[rustc_const_unstable(feature = "const_cstr_methods", issue = "101719")]
+    pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, FromBytesWithNulError> {
         let nul_pos = memchr::memchr(0, bytes);
         match nul_pos {
             Some(nul_pos) if nul_pos + 1 == bytes.len() => {
@@ -498,7 +495,8 @@ impl CStr {
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn to_bytes(&self) -> &[u8] {
+    #[rustc_const_unstable(feature = "const_cstr_methods", issue = "101719")]
+    pub const fn to_bytes(&self) -> &[u8] {
         let bytes = self.to_bytes_with_nul();
         // SAFETY: to_bytes_with_nul returns slice with length at least 1
         unsafe { bytes.get_unchecked(..bytes.len() - 1) }
@@ -525,7 +523,8 @@ impl CStr {
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn to_bytes_with_nul(&self) -> &[u8] {
+    #[rustc_const_unstable(feature = "const_cstr_methods", issue = "101719")]
+    pub const fn to_bytes_with_nul(&self) -> &[u8] {
         // SAFETY: Transmuting a slice of `c_char`s to a slice of `u8`s
         // is safe on all supported targets.
         unsafe { &*(&self.inner as *const [c_char] as *const [u8]) }
@@ -548,7 +547,8 @@ impl CStr {
     /// assert_eq!(cstr.to_str(), Ok("foo"));
     /// ```
     #[stable(feature = "cstr_to_str", since = "1.4.0")]
-    pub fn to_str(&self) -> Result<&str, str::Utf8Error> {
+    #[rustc_const_unstable(feature = "const_cstr_methods", issue = "101719")]
+    pub const fn to_str(&self) -> Result<&str, str::Utf8Error> {
         // N.B., when `CStr` is changed to perform the length check in `.to_bytes()`
         // instead of in `from_ptr()`, it may be worth considering if this should
         // be rewritten to do the UTF-8 check inline with the length calculation
diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index 9d3e9abf5577..905212eb372b 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -1819,7 +1819,7 @@ impl<'a> Formatter<'a> {
     ///             write!(formatter,
     ///                    "Foo({}{})",
     ///                    if self.0 < 0 { '-' } else { '+' },
-    ///                    self.0)
+    ///                    self.0.abs())
     ///         } else {
     ///             write!(formatter, "Foo({})", self.0)
     ///         }
@@ -1827,6 +1827,7 @@ impl<'a> Formatter<'a> {
     /// }
     ///
     /// assert_eq!(&format!("{:+}", Foo(23)), "Foo(+23)");
+    /// assert_eq!(&format!("{:+}", Foo(-23)), "Foo(-23)");
     /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
     /// ```
     #[must_use]
diff --git a/library/core/src/fmt/num.rs b/library/core/src/fmt/num.rs
index 25789d37c269..d8365ae9bf92 100644
--- a/library/core/src/fmt/num.rs
+++ b/library/core/src/fmt/num.rs
@@ -211,7 +211,7 @@ macro_rules! impl_Display {
         fn $name(mut n: $u, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
             // 2^128 is about 3*10^38, so 39 gives an extra byte of space
             let mut buf = [MaybeUninit::<u8>::uninit(); 39];
-            let mut curr = buf.len() as isize;
+            let mut curr = buf.len();
             let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf);
             let lut_ptr = DEC_DIGITS_LUT.as_ptr();
 
@@ -228,7 +228,7 @@ macro_rules! impl_Display {
 
                 // eagerly decode 4 characters at a time
                 while n >= 10000 {
-                    let rem = (n % 10000) as isize;
+                    let rem = (n % 10000) as usize;
                     n /= 10000;
 
                     let d1 = (rem / 100) << 1;
@@ -238,29 +238,29 @@ macro_rules! impl_Display {
                     // We are allowed to copy to `buf_ptr[curr..curr + 3]` here since
                     // otherwise `curr < 0`. But then `n` was originally at least `10000^10`
                     // which is `10^40 > 2^128 > n`.
-                    ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
-                    ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.add(d1), buf_ptr.add(curr), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.add(d2), buf_ptr.add(curr + 2), 2);
                 }
 
                 // if we reach here numbers are <= 9999, so at most 4 chars long
-                let mut n = n as isize; // possibly reduce 64bit math
+                let mut n = n as usize; // possibly reduce 64bit math
 
                 // decode 2 more chars, if > 2 chars
                 if n >= 100 {
                     let d1 = (n % 100) << 1;
                     n /= 100;
                     curr -= 2;
-                    ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.add(d1), buf_ptr.add(curr), 2);
                 }
 
                 // decode last 1 or 2 chars
                 if n < 10 {
                     curr -= 1;
-                    *buf_ptr.offset(curr) = (n as u8) + b'0';
+                    *buf_ptr.add(curr) = (n as u8) + b'0';
                 } else {
                     let d1 = n << 1;
                     curr -= 2;
-                    ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.add(d1), buf_ptr.add(curr), 2);
                 }
             }
 
@@ -268,7 +268,7 @@ macro_rules! impl_Display {
             // UTF-8 since `DEC_DIGITS_LUT` is
             let buf_slice = unsafe {
                 str::from_utf8_unchecked(
-                    slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize))
+                    slice::from_raw_parts(buf_ptr.add(curr), buf.len() - curr))
             };
             f.pad_integral(is_nonnegative, "", buf_slice)
         }
@@ -339,18 +339,18 @@ macro_rules! impl_Exp {
             // Since `curr` always decreases by the number of digits copied, this means
             // that `curr >= 0`.
             let mut buf = [MaybeUninit::<u8>::uninit(); 40];
-            let mut curr = buf.len() as isize; //index for buf
+            let mut curr = buf.len(); //index for buf
             let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf);
             let lut_ptr = DEC_DIGITS_LUT.as_ptr();
 
             // decode 2 chars at a time
             while n >= 100 {
-                let d1 = ((n % 100) as isize) << 1;
+                let d1 = ((n % 100) as usize) << 1;
                 curr -= 2;
                 // SAFETY: `d1 <= 198`, so we can copy from `lut_ptr[d1..d1 + 2]` since
                 // `DEC_DIGITS_LUT` has a length of 200.
                 unsafe {
-                    ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.add(d1), buf_ptr.add(curr), 2);
                 }
                 n /= 100;
                 exponent += 2;
@@ -362,7 +362,7 @@ macro_rules! impl_Exp {
                 curr -= 1;
                 // SAFETY: Safe since `40 > curr >= 0` (see comment)
                 unsafe {
-                    *buf_ptr.offset(curr) = (n as u8 % 10_u8) + b'0';
+                    *buf_ptr.add(curr) = (n as u8 % 10_u8) + b'0';
                 }
                 n /= 10;
                 exponent += 1;
@@ -372,7 +372,7 @@ macro_rules! impl_Exp {
                 curr -= 1;
                 // SAFETY: Safe since `40 > curr >= 0`
                 unsafe {
-                    *buf_ptr.offset(curr) = b'.';
+                    *buf_ptr.add(curr) = b'.';
                 }
             }
 
@@ -380,10 +380,10 @@ macro_rules! impl_Exp {
             let buf_slice = unsafe {
                 // decode last character
                 curr -= 1;
-                *buf_ptr.offset(curr) = (n as u8) + b'0';
+                *buf_ptr.add(curr) = (n as u8) + b'0';
 
                 let len = buf.len() - curr as usize;
-                slice::from_raw_parts(buf_ptr.offset(curr), len)
+                slice::from_raw_parts(buf_ptr.add(curr), len)
             };
 
             // stores 'e' (or 'E') and the up to 2-digit exponent
@@ -392,13 +392,13 @@ macro_rules! impl_Exp {
             // SAFETY: In either case, `exp_buf` is written within bounds and `exp_ptr[..len]`
             // is contained within `exp_buf` since `len <= 3`.
             let exp_slice = unsafe {
-                *exp_ptr.offset(0) = if upper { b'E' } else { b'e' };
+                *exp_ptr.add(0) = if upper { b'E' } else { b'e' };
                 let len = if exponent < 10 {
-                    *exp_ptr.offset(1) = (exponent as u8) + b'0';
+                    *exp_ptr.add(1) = (exponent as u8) + b'0';
                     2
                 } else {
                     let off = exponent << 1;
-                    ptr::copy_nonoverlapping(lut_ptr.offset(off), exp_ptr.offset(1), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.add(off), exp_ptr.add(1), 2);
                     3
                 };
                 slice::from_raw_parts(exp_ptr, len)
@@ -479,7 +479,7 @@ mod imp {
 impl_Exp!(i128, u128 as u128 via to_u128 named exp_u128);
 
 /// Helper function for writing a u64 into `buf` going from last to first, with `curr`.
-fn parse_u64_into<const N: usize>(mut n: u64, buf: &mut [MaybeUninit<u8>; N], curr: &mut isize) {
+fn parse_u64_into<const N: usize>(mut n: u64, buf: &mut [MaybeUninit<u8>; N], curr: &mut usize) {
     let buf_ptr = MaybeUninit::slice_as_mut_ptr(buf);
     let lut_ptr = DEC_DIGITS_LUT.as_ptr();
     assert!(*curr > 19);
@@ -505,14 +505,14 @@ fn parse_u64_into<const N: usize>(mut n: u64, buf: &mut [MaybeUninit<u8>; N], cu
 
             *curr -= 16;
 
-            ptr::copy_nonoverlapping(lut_ptr.offset(d1 as isize), buf_ptr.offset(*curr + 0), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d2 as isize), buf_ptr.offset(*curr + 2), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d3 as isize), buf_ptr.offset(*curr + 4), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d4 as isize), buf_ptr.offset(*curr + 6), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d5 as isize), buf_ptr.offset(*curr + 8), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d6 as isize), buf_ptr.offset(*curr + 10), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d7 as isize), buf_ptr.offset(*curr + 12), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d8 as isize), buf_ptr.offset(*curr + 14), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d1 as usize), buf_ptr.add(*curr + 0), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d2 as usize), buf_ptr.add(*curr + 2), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d3 as usize), buf_ptr.add(*curr + 4), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d4 as usize), buf_ptr.add(*curr + 6), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d5 as usize), buf_ptr.add(*curr + 8), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d6 as usize), buf_ptr.add(*curr + 10), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d7 as usize), buf_ptr.add(*curr + 12), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d8 as usize), buf_ptr.add(*curr + 14), 2);
         }
         if n >= 1e8 as u64 {
             let to_parse = n % 1e8 as u64;
@@ -525,10 +525,10 @@ fn parse_u64_into<const N: usize>(mut n: u64, buf: &mut [MaybeUninit<u8>; N], cu
             let d4 = ((to_parse / 1e0 as u64) % 100) << 1;
             *curr -= 8;
 
-            ptr::copy_nonoverlapping(lut_ptr.offset(d1 as isize), buf_ptr.offset(*curr + 0), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d2 as isize), buf_ptr.offset(*curr + 2), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d3 as isize), buf_ptr.offset(*curr + 4), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d4 as isize), buf_ptr.offset(*curr + 6), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d1 as usize), buf_ptr.add(*curr + 0), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d2 as usize), buf_ptr.add(*curr + 2), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d3 as usize), buf_ptr.add(*curr + 4), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d4 as usize), buf_ptr.add(*curr + 6), 2);
         }
         // `n` < 1e8 < (1 << 32)
         let mut n = n as u32;
@@ -540,8 +540,8 @@ fn parse_u64_into<const N: usize>(mut n: u64, buf: &mut [MaybeUninit<u8>; N], cu
             let d2 = (to_parse % 100) << 1;
             *curr -= 4;
 
-            ptr::copy_nonoverlapping(lut_ptr.offset(d1 as isize), buf_ptr.offset(*curr + 0), 2);
-            ptr::copy_nonoverlapping(lut_ptr.offset(d2 as isize), buf_ptr.offset(*curr + 2), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d1 as usize), buf_ptr.add(*curr + 0), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d2 as usize), buf_ptr.add(*curr + 2), 2);
         }
 
         // `n` < 1e4 < (1 << 16)
@@ -550,17 +550,17 @@ fn parse_u64_into<const N: usize>(mut n: u64, buf: &mut [MaybeUninit<u8>; N], cu
             let d1 = (n % 100) << 1;
             n /= 100;
             *curr -= 2;
-            ptr::copy_nonoverlapping(lut_ptr.offset(d1 as isize), buf_ptr.offset(*curr), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d1 as usize), buf_ptr.add(*curr), 2);
         }
 
         // decode last 1 or 2 chars
         if n < 10 {
             *curr -= 1;
-            *buf_ptr.offset(*curr) = (n as u8) + b'0';
+            *buf_ptr.add(*curr) = (n as u8) + b'0';
         } else {
             let d1 = n << 1;
             *curr -= 2;
-            ptr::copy_nonoverlapping(lut_ptr.offset(d1 as isize), buf_ptr.offset(*curr), 2);
+            ptr::copy_nonoverlapping(lut_ptr.add(d1 as usize), buf_ptr.add(*curr), 2);
         }
     }
 }
@@ -593,21 +593,21 @@ impl fmt::Display for i128 {
 fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     // 2^128 is about 3*10^38, so 39 gives an extra byte of space
     let mut buf = [MaybeUninit::<u8>::uninit(); 39];
-    let mut curr = buf.len() as isize;
+    let mut curr = buf.len();
 
     let (n, rem) = udiv_1e19(n);
     parse_u64_into(rem, &mut buf, &mut curr);
 
     if n != 0 {
         // 0 pad up to point
-        let target = (buf.len() - 19) as isize;
+        let target = buf.len() - 19;
         // SAFETY: Guaranteed that we wrote at most 19 bytes, and there must be space
         // remaining since it has length 39
         unsafe {
             ptr::write_bytes(
-                MaybeUninit::slice_as_mut_ptr(&mut buf).offset(target),
+                MaybeUninit::slice_as_mut_ptr(&mut buf).add(target),
                 b'0',
-                (curr - target) as usize,
+                curr - target,
             );
         }
         curr = target;
@@ -616,16 +616,16 @@ fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::R
         parse_u64_into(rem, &mut buf, &mut curr);
         // Should this following branch be annotated with unlikely?
         if n != 0 {
-            let target = (buf.len() - 38) as isize;
+            let target = buf.len() - 38;
             // The raw `buf_ptr` pointer is only valid until `buf` is used the next time,
             // buf `buf` is not used in this scope so we are good.
             let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf);
             // SAFETY: At this point we wrote at most 38 bytes, pad up to that point,
             // There can only be at most 1 digit remaining.
             unsafe {
-                ptr::write_bytes(buf_ptr.offset(target), b'0', (curr - target) as usize);
+                ptr::write_bytes(buf_ptr.add(target), b'0', curr - target);
                 curr = target - 1;
-                *buf_ptr.offset(curr) = (n as u8) + b'0';
+                *buf_ptr.add(curr) = (n as u8) + b'0';
             }
         }
     }
@@ -634,8 +634,8 @@ fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::R
     // UTF-8 since `DEC_DIGITS_LUT` is
     let buf_slice = unsafe {
         str::from_utf8_unchecked(slice::from_raw_parts(
-            MaybeUninit::slice_as_mut_ptr(&mut buf).offset(curr),
-            buf.len() - curr as usize,
+            MaybeUninit::slice_as_mut_ptr(&mut buf).add(curr),
+            buf.len() - curr,
         ))
     };
     f.pad_integral(is_nonnegative, "", buf_slice)
diff --git a/library/core/src/hint.rs b/library/core/src/hint.rs
index 81b6d5737ea7..764e2796202c 100644
--- a/library/core/src/hint.rs
+++ b/library/core/src/hint.rs
@@ -31,7 +31,7 @@ use crate::intrinsics;
 ///
 /// `unreachable_unchecked()` can be used in situations where the compiler
 /// can't prove invariants that were previously established. Such situations
-/// have a higher chance of occuring if those invariants are upheld by
+/// have a higher chance of occurring if those invariants are upheld by
 /// external code that the compiler can't analyze.
 /// ```
 /// fn prepare_inputs(divisors: &mut Vec<u32>) {
@@ -160,19 +160,16 @@ pub const unsafe fn unreachable_unchecked() -> ! {
 #[inline]
 #[stable(feature = "renamed_spin_loop", since = "1.49.0")]
 pub fn spin_loop() {
-    #[cfg(all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "sse2"))]
+    #[cfg(target_arch = "x86")]
     {
-        #[cfg(target_arch = "x86")]
-        {
-            // SAFETY: the `cfg` attr ensures that we only execute this on x86 targets.
-            unsafe { crate::arch::x86::_mm_pause() };
-        }
+        // SAFETY: the `cfg` attr ensures that we only execute this on x86 targets.
+        unsafe { crate::arch::x86::_mm_pause() };
+    }
 
-        #[cfg(target_arch = "x86_64")]
-        {
-            // SAFETY: the `cfg` attr ensures that we only execute this on x86_64 targets.
-            unsafe { crate::arch::x86_64::_mm_pause() };
-        }
+    #[cfg(target_arch = "x86_64")]
+    {
+        // SAFETY: the `cfg` attr ensures that we only execute this on x86_64 targets.
+        unsafe { crate::arch::x86_64::_mm_pause() };
     }
 
     // RISC-V platform spin loop hint implementation
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 5f8e6efa0cf5..12b43da5a428 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -54,7 +54,7 @@
 )]
 #![allow(missing_docs)]
 
-use crate::marker::{Destruct, DiscriminantKind};
+use crate::marker::DiscriminantKind;
 use crate::mem;
 
 // These imports are used for simplifying intra-doc links
@@ -1082,7 +1082,7 @@ extern "rust-intrinsic" {
     /// Note that using `transmute` to turn a pointer to a `usize` is (as noted above) [undefined
     /// behavior][ub] in `const` contexts. Also outside of consts, this operation might not behave
     /// as expected -- this is touching on many unspecified aspects of the Rust memory model.
-    /// Depending on what the code is doing, the following alternatives are preferrable to
+    /// Depending on what the code is doing, the following alternatives are preferable to
     /// pointer-to-integer transmutation:
     /// - If the code just wants to store data of arbitrary type in some buffer and needs to pick a
     ///   type for that buffer, it can use [`MaybeUninit`][mem::MaybeUninit].
@@ -1295,7 +1295,6 @@ extern "rust-intrinsic" {
     /// any safety invariants.
     ///
     /// Consider using [`pointer::mask`] instead.
-    #[cfg(not(bootstrap))]
     pub fn ptr_mask<T>(ptr: *const T, mask: usize) -> *const T;
 
     /// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with
@@ -2011,22 +2010,16 @@ extern "rust-intrinsic" {
     pub fn ptr_offset_from_unsigned<T>(ptr: *const T, base: *const T) -> usize;
 
     /// See documentation of `<*const T>::guaranteed_eq` for details.
+    /// Returns `2` if the result is unknown.
+    /// Returns `1` if the pointers are guaranteed equal
+    /// Returns `0` if the pointers are guaranteed inequal
     ///
     /// Note that, unlike most intrinsics, this is safe to call;
     /// it does not require an `unsafe` block.
     /// Therefore, implementations must not require the user to uphold
     /// any safety invariants.
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
-    pub fn ptr_guaranteed_eq<T>(ptr: *const T, other: *const T) -> bool;
-
-    /// See documentation of `<*const T>::guaranteed_ne` for details.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
-    pub fn ptr_guaranteed_ne<T>(ptr: *const T, other: *const T) -> bool;
+    pub fn ptr_guaranteed_cmp<T>(ptr: *const T, other: *const T) -> u8;
 
     /// Allocates a block of memory at compile time.
     /// At runtime, just returns a null pointer.
@@ -2085,6 +2078,64 @@ extern "rust-intrinsic" {
     /// `ptr` must point to a vtable.
     /// The intrinsic will return the alignment stored in that vtable.
     pub fn vtable_align(ptr: *const ()) -> usize;
+
+    /// Selects which function to call depending on the context.
+    ///
+    /// If this function is evaluated at compile-time, then a call to this
+    /// intrinsic will be replaced with a call to `called_in_const`. It gets
+    /// replaced with a call to `called_at_rt` otherwise.
+    ///
+    /// # Type Requirements
+    ///
+    /// The two functions must be both function items. They cannot be function
+    /// pointers or closures. The first function must be a `const fn`.
+    ///
+    /// `arg` will be the tupled arguments that will be passed to either one of
+    /// the two functions, therefore, both functions must accept the same type of
+    /// arguments. Both functions must return RET.
+    ///
+    /// # Safety
+    ///
+    /// The two functions must behave observably equivalent. Safe code in other
+    /// crates may assume that calling a `const fn` at compile-time and at run-time
+    /// produces the same result. A function that produces a different result when
+    /// evaluated at run-time, or has any other observable side-effects, is
+    /// *unsound*.
+    ///
+    /// Here is an example of how this could cause a problem:
+    /// ```no_run
+    /// #![feature(const_eval_select)]
+    /// #![feature(core_intrinsics)]
+    /// use std::hint::unreachable_unchecked;
+    /// use std::intrinsics::const_eval_select;
+    ///
+    /// // Crate A
+    /// pub const fn inconsistent() -> i32 {
+    ///     fn runtime() -> i32 { 1 }
+    ///     const fn compiletime() -> i32 { 2 }
+    ///
+    ///     unsafe {
+    //          // ⚠ This code violates the required equivalence of `compiletime`
+    ///         // and `runtime`.
+    ///         const_eval_select((), compiletime, runtime)
+    ///     }
+    /// }
+    ///
+    /// // Crate B
+    /// const X: i32 = inconsistent();
+    /// let x = inconsistent();
+    /// if x != X { unsafe { unreachable_unchecked(); }}
+    /// ```
+    ///
+    /// This code causes Undefined Behavior when being run, since the
+    /// `unreachable_unchecked` is actually being reached. The bug is in *crate A*,
+    /// which violates the principle that a `const fn` must behave the same at
+    /// compile-time and at run-time. The unsafe code in crate B is fine.
+    #[rustc_const_unstable(feature = "const_eval_select", issue = "none")]
+    pub fn const_eval_select<ARG, F, G, RET>(arg: ARG, called_in_const: F, called_at_rt: G) -> RET
+    where
+        G: FnOnce<ARG, Output = RET>,
+        F: FnOnce<ARG, Output = RET>;
 }
 
 // Some functions are defined here because they accidentally got made
@@ -2095,6 +2146,11 @@ extern "rust-intrinsic" {
 /// Check that the preconditions of an unsafe function are followed, if debug_assertions are on,
 /// and only at runtime.
 ///
+/// This macro should be called as `assert_unsafe_precondition!([Generics](name: Type) => Expression)`
+/// where the names specified will be moved into the macro as captured variables, and defines an item
+/// to call `const_eval_select` on. The tokens inside the square brackets are used to denote generics
+/// for the function declaractions and can be omitted if there is no generics.
+///
 /// # Safety
 ///
 /// Invoking this macro is only sound if the following code is already UB when the passed
@@ -2109,18 +2165,21 @@ extern "rust-intrinsic" {
 /// the occasional mistake, and this check should help them figure things out.
 #[allow_internal_unstable(const_eval_select)] // permit this to be called in stably-const fn
 macro_rules! assert_unsafe_precondition {
-    ($e:expr) => {
+    ($([$($tt:tt)*])?($($i:ident:$ty:ty),*$(,)?) => $e:expr) => {
         if cfg!(debug_assertions) {
-            // Use a closure so that we can capture arbitrary expressions from the invocation
-            let runtime = || {
+            // allow non_snake_case to allow capturing const generics
+            #[allow(non_snake_case)]
+            #[inline(always)]
+            fn runtime$(<$($tt)*>)?($($i:$ty),*) {
                 if !$e {
                     // abort instead of panicking to reduce impact on code size
                     ::core::intrinsics::abort();
                 }
-            };
-            const fn comptime() {}
+            }
+            #[allow(non_snake_case)]
+            const fn comptime$(<$($tt)*>)?($(_:$ty),*) {}
 
-            ::core::intrinsics::const_eval_select((), comptime, runtime);
+            ::core::intrinsics::const_eval_select(($($i,)*), comptime, runtime);
         }
     };
 }
@@ -2243,7 +2302,7 @@ pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: us
     // SAFETY: the safety contract for `copy_nonoverlapping` must be
     // upheld by the caller.
     unsafe {
-        assert_unsafe_precondition!(
+        assert_unsafe_precondition!([T](src: *const T, dst: *mut T, count: usize) =>
             is_aligned_and_not_null(src)
                 && is_aligned_and_not_null(dst)
                 && is_nonoverlapping(src, dst, count)
@@ -2329,7 +2388,8 @@ pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) {
 
     // SAFETY: the safety contract for `copy` must be upheld by the caller.
     unsafe {
-        assert_unsafe_precondition!(is_aligned_and_not_null(src) && is_aligned_and_not_null(dst));
+        assert_unsafe_precondition!([T](src: *const T, dst: *mut T) =>
+            is_aligned_and_not_null(src) && is_aligned_and_not_null(dst));
         copy(src, dst, count)
     }
 }
@@ -2397,99 +2457,7 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
 
     // SAFETY: the safety contract for `write_bytes` must be upheld by the caller.
     unsafe {
-        assert_unsafe_precondition!(is_aligned_and_not_null(dst));
+        assert_unsafe_precondition!([T](dst: *mut T) => is_aligned_and_not_null(dst));
         write_bytes(dst, val, count)
     }
 }
-
-/// Selects which function to call depending on the context.
-///
-/// If this function is evaluated at compile-time, then a call to this
-/// intrinsic will be replaced with a call to `called_in_const`. It gets
-/// replaced with a call to `called_at_rt` otherwise.
-///
-/// # Type Requirements
-///
-/// The two functions must be both function items. They cannot be function
-/// pointers or closures.
-///
-/// `arg` will be the arguments that will be passed to either one of the
-/// two functions, therefore, both functions must accept the same type of
-/// arguments. Both functions must return RET.
-///
-/// # Safety
-///
-/// The two functions must behave observably equivalent. Safe code in other
-/// crates may assume that calling a `const fn` at compile-time and at run-time
-/// produces the same result. A function that produces a different result when
-/// evaluated at run-time, or has any other observable side-effects, is
-/// *unsound*.
-///
-/// Here is an example of how this could cause a problem:
-/// ```no_run
-/// #![feature(const_eval_select)]
-/// #![feature(core_intrinsics)]
-/// use std::hint::unreachable_unchecked;
-/// use std::intrinsics::const_eval_select;
-///
-/// // Crate A
-/// pub const fn inconsistent() -> i32 {
-///     fn runtime() -> i32 { 1 }
-///     const fn compiletime() -> i32 { 2 }
-///
-///     unsafe {
-//          // ⚠ This code violates the required equivalence of `compiletime`
-///         // and `runtime`.
-///         const_eval_select((), compiletime, runtime)
-///     }
-/// }
-///
-/// // Crate B
-/// const X: i32 = inconsistent();
-/// let x = inconsistent();
-/// if x != X { unsafe { unreachable_unchecked(); }}
-/// ```
-///
-/// This code causes Undefined Behavior when being run, since the
-/// `unreachable_unchecked` is actually being reached. The bug is in *crate A*,
-/// which violates the principle that a `const fn` must behave the same at
-/// compile-time and at run-time. The unsafe code in crate B is fine.
-#[unstable(
-    feature = "const_eval_select",
-    issue = "none",
-    reason = "const_eval_select will never be stable"
-)]
-#[rustc_const_unstable(feature = "const_eval_select", issue = "none")]
-#[lang = "const_eval_select"]
-#[rustc_do_not_const_check]
-#[inline]
-pub const unsafe fn const_eval_select<ARG, F, G, RET>(
-    arg: ARG,
-    _called_in_const: F,
-    called_at_rt: G,
-) -> RET
-where
-    F: ~const FnOnce<ARG, Output = RET>,
-    G: FnOnce<ARG, Output = RET> + ~const Destruct,
-{
-    called_at_rt.call_once(arg)
-}
-
-#[unstable(
-    feature = "const_eval_select",
-    issue = "none",
-    reason = "const_eval_select will never be stable"
-)]
-#[rustc_const_unstable(feature = "const_eval_select", issue = "none")]
-#[lang = "const_eval_select_ct"]
-pub const unsafe fn const_eval_select_ct<ARG, F, G, RET>(
-    arg: ARG,
-    called_in_const: F,
-    _called_at_rt: G,
-) -> RET
-where
-    F: ~const FnOnce<ARG, Output = RET>,
-    G: FnOnce<ARG, Output = RET> + ~const Destruct,
-{
-    called_in_const.call_once(arg)
-}
diff --git a/library/core/src/iter/adapters/array_chunks.rs b/library/core/src/iter/adapters/array_chunks.rs
index 9b479a9f8adf..489fb13c0dc9 100644
--- a/library/core/src/iter/adapters/array_chunks.rs
+++ b/library/core/src/iter/adapters/array_chunks.rs
@@ -1,4 +1,5 @@
 use crate::array;
+use crate::const_closure::ConstFnMutClosure;
 use crate::iter::{ByRefSized, FusedIterator, Iterator};
 use crate::ops::{ControlFlow, NeverShortCircuit, Try};
 
@@ -82,12 +83,12 @@ where
         }
     }
 
-    fn fold<B, F>(mut self, init: B, f: F) -> B
+    fn fold<B, F>(mut self, init: B, mut f: F) -> B
     where
         Self: Sized,
         F: FnMut(B, Self::Item) -> B,
     {
-        self.try_fold(init, NeverShortCircuit::wrap_mut_2(f)).0
+        self.try_fold(init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp)).0
     }
 }
 
@@ -126,12 +127,12 @@ where
         try { acc }
     }
 
-    fn rfold<B, F>(mut self, init: B, f: F) -> B
+    fn rfold<B, F>(mut self, init: B, mut f: F) -> B
     where
         Self: Sized,
         F: FnMut(B, Self::Item) -> B,
     {
-        self.try_rfold(init, NeverShortCircuit::wrap_mut_2(f)).0
+        self.try_rfold(init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp)).0
     }
 }
 
diff --git a/library/core/src/iter/adapters/by_ref_sized.rs b/library/core/src/iter/adapters/by_ref_sized.rs
index 477e7117c3ea..1945e402ff50 100644
--- a/library/core/src/iter/adapters/by_ref_sized.rs
+++ b/library/core/src/iter/adapters/by_ref_sized.rs
@@ -1,4 +1,7 @@
-use crate::ops::{NeverShortCircuit, Try};
+use crate::{
+    const_closure::ConstFnMutClosure,
+    ops::{NeverShortCircuit, Try},
+};
 
 /// Like `Iterator::by_ref`, but requiring `Sized` so it can forward generics.
 ///
@@ -36,12 +39,13 @@ impl<I: Iterator> Iterator for ByRefSized<'_, I> {
     }
 
     #[inline]
-    fn fold<B, F>(self, init: B, f: F) -> B
+    fn fold<B, F>(self, init: B, mut f: F) -> B
     where
         F: FnMut(B, Self::Item) -> B,
     {
         // `fold` needs ownership, so this can't forward directly.
-        I::try_fold(self.0, init, NeverShortCircuit::wrap_mut_2(f)).0
+        I::try_fold(self.0, init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp))
+            .0
     }
 
     #[inline]
@@ -72,12 +76,17 @@ impl<I: DoubleEndedIterator> DoubleEndedIterator for ByRefSized<'_, I> {
     }
 
     #[inline]
-    fn rfold<B, F>(self, init: B, f: F) -> B
+    fn rfold<B, F>(self, init: B, mut f: F) -> B
     where
         F: FnMut(B, Self::Item) -> B,
     {
         // `rfold` needs ownership, so this can't forward directly.
-        I::try_rfold(self.0, init, NeverShortCircuit::wrap_mut_2(f)).0
+        I::try_rfold(
+            self.0,
+            init,
+            ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp),
+        )
+        .0
     }
 
     #[inline]
diff --git a/library/core/src/iter/adapters/mod.rs b/library/core/src/iter/adapters/mod.rs
index bf4fabad32a3..de3a534f81b8 100644
--- a/library/core/src/iter/adapters/mod.rs
+++ b/library/core/src/iter/adapters/mod.rs
@@ -1,3 +1,4 @@
+use crate::const_closure::ConstFnMutClosure;
 use crate::iter::{InPlaceIterable, Iterator};
 use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, NeverShortCircuit, Residual, Try};
 
@@ -203,12 +204,12 @@ where
             .into_try()
     }
 
-    fn fold<B, F>(mut self, init: B, fold: F) -> B
+    fn fold<B, F>(mut self, init: B, mut fold: F) -> B
     where
         Self: Sized,
         F: FnMut(B, Self::Item) -> B,
     {
-        self.try_fold(init, NeverShortCircuit::wrap_mut_2(fold)).0
+        self.try_fold(init, ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp)).0
     }
 }
 
diff --git a/library/core/src/iter/traits/collect.rs b/library/core/src/iter/traits/collect.rs
index 12ca508bed2b..e598a54b4f15 100644
--- a/library/core/src/iter/traits/collect.rs
+++ b/library/core/src/iter/traits/collect.rs
@@ -228,6 +228,7 @@ pub trait FromIterator<A>: Sized {
 #[rustc_diagnostic_item = "IntoIterator"]
 #[rustc_skip_array_during_method_dispatch]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait IntoIterator {
     /// The type of the elements being iterated over.
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index b2d08f4b0f67..e26920b25ccf 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -2906,14 +2906,14 @@ pub trait Iterator {
     /// Stopping at the first `true`:
     ///
     /// ```
-    /// let a = [1, 2, 3];
+    /// let a = [-1, 2, 3, 4];
     ///
     /// let mut iter = a.iter();
     ///
-    /// assert_eq!(iter.rposition(|&x| x == 2), Some(1));
+    /// assert_eq!(iter.rposition(|&x| x >= 2), Some(3));
     ///
     /// // we can still use `iter`, as there are more elements.
-    /// assert_eq!(iter.next(), Some(&1));
+    /// assert_eq!(iter.next(), Some(&-1));
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -3461,36 +3461,27 @@ pub trait Iterator {
     /// assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (2 * x).cmp(&y)), Ordering::Greater);
     /// ```
     #[unstable(feature = "iter_order_by", issue = "64295")]
-    fn cmp_by<I, F>(mut self, other: I, mut cmp: F) -> Ordering
+    fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering
     where
         Self: Sized,
         I: IntoIterator,
         F: FnMut(Self::Item, I::Item) -> Ordering,
     {
-        let mut other = other.into_iter();
-
-        loop {
-            let x = match self.next() {
-                None => {
-                    if other.next().is_none() {
-                        return Ordering::Equal;
-                    } else {
-                        return Ordering::Less;
-                    }
-                }
-                Some(val) => val,
-            };
-
-            let y = match other.next() {
-                None => return Ordering::Greater,
-                Some(val) => val,
-            };
-
-            match cmp(x, y) {
-                Ordering::Equal => (),
-                non_eq => return non_eq,
+        #[inline]
+        fn compare<X, Y, F>(mut cmp: F) -> impl FnMut(X, Y) -> ControlFlow<Ordering>
+        where
+            F: FnMut(X, Y) -> Ordering,
+        {
+            move |x, y| match cmp(x, y) {
+                Ordering::Equal => ControlFlow::CONTINUE,
+                non_eq => ControlFlow::Break(non_eq),
             }
         }
+
+        match iter_compare(self, other.into_iter(), compare(cmp)) {
+            ControlFlow::Continue(ord) => ord,
+            ControlFlow::Break(ord) => ord,
+        }
     }
 
     /// [Lexicographically](Ord#lexicographical-comparison) compares the elements of this [`Iterator`] with those
@@ -3546,36 +3537,27 @@ pub trait Iterator {
     /// );
     /// ```
     #[unstable(feature = "iter_order_by", issue = "64295")]
-    fn partial_cmp_by<I, F>(mut self, other: I, mut partial_cmp: F) -> Option<Ordering>
+    fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>
     where
         Self: Sized,
         I: IntoIterator,
         F: FnMut(Self::Item, I::Item) -> Option<Ordering>,
     {
-        let mut other = other.into_iter();
-
-        loop {
-            let x = match self.next() {
-                None => {
-                    if other.next().is_none() {
-                        return Some(Ordering::Equal);
-                    } else {
-                        return Some(Ordering::Less);
-                    }
-                }
-                Some(val) => val,
-            };
-
-            let y = match other.next() {
-                None => return Some(Ordering::Greater),
-                Some(val) => val,
-            };
-
-            match partial_cmp(x, y) {
-                Some(Ordering::Equal) => (),
-                non_eq => return non_eq,
+        #[inline]
+        fn compare<X, Y, F>(mut partial_cmp: F) -> impl FnMut(X, Y) -> ControlFlow<Option<Ordering>>
+        where
+            F: FnMut(X, Y) -> Option<Ordering>,
+        {
+            move |x, y| match partial_cmp(x, y) {
+                Some(Ordering::Equal) => ControlFlow::CONTINUE,
+                non_eq => ControlFlow::Break(non_eq),
             }
         }
+
+        match iter_compare(self, other.into_iter(), compare(partial_cmp)) {
+            ControlFlow::Continue(ord) => Some(ord),
+            ControlFlow::Break(ord) => ord,
+        }
     }
 
     /// Determines if the elements of this [`Iterator`] are equal to those of
@@ -3613,29 +3595,26 @@ pub trait Iterator {
     /// assert!(xs.iter().eq_by(&ys, |&x, &y| x * x == y));
     /// ```
     #[unstable(feature = "iter_order_by", issue = "64295")]
-    fn eq_by<I, F>(mut self, other: I, mut eq: F) -> bool
+    fn eq_by<I, F>(self, other: I, eq: F) -> bool
     where
         Self: Sized,
         I: IntoIterator,
         F: FnMut(Self::Item, I::Item) -> bool,
     {
-        let mut other = other.into_iter();
-
-        loop {
-            let x = match self.next() {
-                None => return other.next().is_none(),
-                Some(val) => val,
-            };
-
-            let y = match other.next() {
-                None => return false,
-                Some(val) => val,
-            };
-
-            if !eq(x, y) {
-                return false;
+        #[inline]
+        fn compare<X, Y, F>(mut eq: F) -> impl FnMut(X, Y) -> ControlFlow<()>
+        where
+            F: FnMut(X, Y) -> bool,
+        {
+            move |x, y| {
+                if eq(x, y) { ControlFlow::CONTINUE } else { ControlFlow::BREAK }
             }
         }
+
+        match iter_compare(self, other.into_iter(), compare(eq)) {
+            ControlFlow::Continue(ord) => ord == Ordering::Equal,
+            ControlFlow::Break(()) => false,
+        }
     }
 
     /// Determines if the elements of this [`Iterator`] are unequal to those of
@@ -3860,6 +3839,46 @@ pub trait Iterator {
     }
 }
 
+/// Compares two iterators element-wise using the given function.
+///
+/// If `ControlFlow::CONTINUE` is returned from the function, the comparison moves on to the next
+/// elements of both iterators. Returning `ControlFlow::Break(x)` short-circuits the iteration and
+/// returns `ControlFlow::Break(x)`. If one of the iterators runs out of elements,
+/// `ControlFlow::Continue(ord)` is returned where `ord` is the result of comparing the lengths of
+/// the iterators.
+///
+/// Isolates the logic shared by ['cmp_by'](Iterator::cmp_by),
+/// ['partial_cmp_by'](Iterator::partial_cmp_by), and ['eq_by'](Iterator::eq_by).
+#[inline]
+fn iter_compare<A, B, F, T>(mut a: A, mut b: B, f: F) -> ControlFlow<T, Ordering>
+where
+    A: Iterator,
+    B: Iterator,
+    F: FnMut(A::Item, B::Item) -> ControlFlow<T>,
+{
+    #[inline]
+    fn compare<'a, B, X, T>(
+        b: &'a mut B,
+        mut f: impl FnMut(X, B::Item) -> ControlFlow<T> + 'a,
+    ) -> impl FnMut(X) -> ControlFlow<ControlFlow<T, Ordering>> + 'a
+    where
+        B: Iterator,
+    {
+        move |x| match b.next() {
+            None => ControlFlow::Break(ControlFlow::Continue(Ordering::Greater)),
+            Some(y) => f(x, y).map_break(ControlFlow::Break),
+        }
+    }
+
+    match a.try_for_each(compare(&mut b, f)) {
+        ControlFlow::Continue(()) => ControlFlow::Continue(match b.next() {
+            None => Ordering::Equal,
+            Some(_) => Ordering::Less,
+        }),
+        ControlFlow::Break(x) => x,
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<I: Iterator + ?Sized> Iterator for &mut I {
     type Item = I::Item;
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index bf75796f1fcb..5690b5256e88 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -93,6 +93,7 @@
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]
 #![allow(explicit_outlives_requirements)]
+#![allow(incomplete_features)]
 //
 // Library features:
 #![feature(const_align_offset)]
@@ -113,6 +114,7 @@
 #![feature(const_fmt_arguments_new)]
 #![feature(const_heap)]
 #![feature(const_convert)]
+#![feature(const_index_range_slice_index)]
 #![feature(const_inherent_unchecked_arith)]
 #![feature(const_int_unchecked_arith)]
 #![feature(const_intrinsic_forget)]
@@ -136,13 +138,17 @@
 #![feature(const_size_of_val)]
 #![feature(const_slice_from_raw_parts_mut)]
 #![feature(const_slice_ptr_len)]
+#![feature(const_slice_split_at_mut)]
 #![feature(const_str_from_utf8_unchecked_mut)]
 #![feature(const_swap)]
 #![feature(const_trait_impl)]
+#![feature(const_try)]
 #![feature(const_type_id)]
 #![feature(const_type_name)]
 #![feature(const_default_impls)]
+#![feature(const_unicode_case_lookup)]
 #![feature(const_unsafecell_get_mut)]
+#![feature(const_waker)]
 #![feature(core_panic)]
 #![feature(duration_consts_float)]
 #![feature(maybe_uninit_uninit_array)]
@@ -157,9 +163,11 @@
 #![feature(const_slice_from_ref)]
 #![feature(const_slice_index)]
 #![feature(const_is_char_boundary)]
+#![feature(const_cstr_methods)]
 //
 // Language features:
 #![feature(abi_unadjusted)]
+#![feature(adt_const_params)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
 #![feature(associated_type_bounds)]
@@ -302,7 +310,6 @@ pub mod clone;
 pub mod cmp;
 pub mod convert;
 pub mod default;
-#[cfg(not(bootstrap))]
 pub mod error;
 pub mod marker;
 pub mod ops;
@@ -349,6 +356,8 @@ mod bool;
 mod tuple;
 mod unit;
 
+mod const_closure;
+
 #[stable(feature = "core_primitive", since = "1.43.0")]
 pub mod primitive;
 
diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs
index 0bd9c8e9acfc..fd96e1ff77d5 100644
--- a/library/core/src/macros/mod.rs
+++ b/library/core/src/macros/mod.rs
@@ -350,10 +350,12 @@ macro_rules! matches {
 
 /// Unwraps a result or propagates its error.
 ///
-/// The `?` operator was added to replace `try!` and should be used instead.
-/// Furthermore, `try` is a reserved word in Rust 2018, so if you must use
-/// it, you will need to use the [raw-identifier syntax][ris]: `r#try`.
+/// The [`?` operator][propagating-errors] was added to replace `try!`
+/// and should be used instead. Furthermore, `try` is a reserved word
+/// in Rust 2018, so if you must use it, you will need to use the
+/// [raw-identifier syntax][ris]: `r#try`.
 ///
+/// [propagating-errors]: https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
 /// [ris]: https://doc.rust-lang.org/nightly/rust-by-example/compatibility/raw_identifiers.html
 ///
 /// `try!` matches the given [`Result`]. In case of the `Ok` variant, the
@@ -1014,7 +1016,7 @@ pub(crate) mod builtin {
     /// Concatenates literals into a byte slice.
     ///
     /// This macro takes any number of comma-separated literals, and concatenates them all into
-    /// one, yielding an expression of type `&[u8, _]`, which represents all of the literals
+    /// one, yielding an expression of type `&[u8; _]`, which represents all of the literals
     /// concatenated left-to-right. The literals passed can be any combination of:
     ///
     /// - byte literals (`b'r'`)
diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs
index ab673c623b5d..5cb5e4458cc6 100644
--- a/library/core/src/marker.rs
+++ b/library/core/src/marker.rs
@@ -81,6 +81,7 @@ impl<T: ?Sized> !Send for *mut T {}
 /// ```
 ///
 /// [trait object]: ../../book/ch17-02-trait-objects.html
+#[doc(alias = "?", alias = "?Sized")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[lang = "sized"]
 #[rustc_on_unimplemented(
@@ -800,6 +801,15 @@ impl<T: ?Sized> Unpin for *mut T {}
 #[rustc_on_unimplemented(message = "can't drop `{Self}`", append_const_msg)]
 pub trait Destruct {}
 
+/// A marker for tuple types.
+///
+/// The implementation of this trait is built-in and cannot be implemented
+/// for any user type.
+#[unstable(feature = "tuple_trait", issue = "none")]
+#[lang = "tuple_trait"]
+#[rustc_on_unimplemented(message = "`{Self}` is not a tuple")]
+pub trait Tuple {}
+
 /// Implementations of `Copy` for primitive types.
 ///
 /// Implementations that cannot be described in Rust
diff --git a/library/core/src/mem/mod.rs b/library/core/src/mem/mod.rs
index d2dd2941d590..66fca2fd2814 100644
--- a/library/core/src/mem/mod.rs
+++ b/library/core/src/mem/mod.rs
@@ -1178,3 +1178,44 @@ pub const fn discriminant<T>(v: &T) -> Discriminant<T> {
 pub const fn variant_count<T>() -> usize {
     intrinsics::variant_count::<T>()
 }
+
+/// Provides associated constants for various useful properties of types,
+/// to give them a canonical form in our code and make them easier to read.
+///
+/// This is here only to simplify all the ZST checks we need in the library.
+/// It's not on a stabilization track right now.
+#[doc(hidden)]
+#[unstable(feature = "sized_type_properties", issue = "none")]
+pub trait SizedTypeProperties: Sized {
+    /// `true` if this type requires no storage.
+    /// `false` if its [size](size_of) is greater than zero.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(sized_type_properties)]
+    /// use core::mem::SizedTypeProperties;
+    ///
+    /// fn do_something_with<T>() {
+    ///     if T::IS_ZST {
+    ///         // ... special approach ...
+    ///     } else {
+    ///         // ... the normal thing ...
+    ///     }
+    /// }
+    ///
+    /// struct MyUnit;
+    /// assert!(MyUnit::IS_ZST);
+    ///
+    /// // For negative checks, consider using UFCS to emphasize the negation
+    /// assert!(!<i32>::IS_ZST);
+    /// // As it can sometimes hide in the type otherwise
+    /// assert!(!String::IS_ZST);
+    /// ```
+    #[doc(hidden)]
+    #[unstable(feature = "sized_type_properties", issue = "none")]
+    const IS_ZST: bool = size_of::<Self>() == 0;
+}
+#[doc(hidden)]
+#[unstable(feature = "sized_type_properties", issue = "none")]
+impl<T> SizedTypeProperties for T {}
diff --git a/library/core/src/mem/transmutability.rs b/library/core/src/mem/transmutability.rs
index b4fabedad782..3b98efff2938 100644
--- a/library/core/src/mem/transmutability.rs
+++ b/library/core/src/mem/transmutability.rs
@@ -9,20 +9,15 @@
     message = "`{Src}` cannot be safely transmuted into `{Self}` in the defining scope of `{Context}`.",
     label = "`{Src}` cannot be safely transmuted into `{Self}` in the defining scope of `{Context}`."
 )]
-pub unsafe trait BikeshedIntrinsicFrom<
-    Src,
-    Context,
-    const ASSUME_ALIGNMENT: bool,
-    const ASSUME_LIFETIMES: bool,
-    const ASSUME_VALIDITY: bool,
-    const ASSUME_VISIBILITY: bool,
-> where
+pub unsafe trait BikeshedIntrinsicFrom<Src, Context, const ASSUME: Assume = { Assume::NOTHING }>
+where
     Src: ?Sized,
 {
 }
 
 /// What transmutation safety conditions shall the compiler assume that *you* are checking?
 #[unstable(feature = "transmutability", issue = "99571")]
+#[lang = "transmute_opts"]
 #[derive(PartialEq, Eq, Clone, Copy, Debug)]
 pub struct Assume {
     /// When `true`, the compiler assumes that *you* are ensuring (either dynamically or statically) that
@@ -33,11 +28,80 @@ pub struct Assume {
     /// that violates Rust's memory model.
     pub lifetimes: bool,
 
+    /// When `true`, the compiler assumes that *you* have ensured that it is safe for you to violate the
+    /// type and field privacy of the destination type (and sometimes of the source type, too).
+    pub safety: bool,
+
     /// When `true`, the compiler assumes that *you* are ensuring that the source type is actually a valid
     /// instance of the destination type.
     pub validity: bool,
-
-    /// When `true`, the compiler assumes that *you* have ensured that it is safe for you to violate the
-    /// type and field privacy of the destination type (and sometimes of the source type, too).
-    pub visibility: bool,
+}
+
+impl Assume {
+    /// Do not assume that *you* have ensured any safety properties are met.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const NOTHING: Self =
+        Self { alignment: false, lifetimes: false, safety: false, validity: false };
+
+    /// Assume only that alignment conditions are met.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const ALIGNMENT: Self = Self { alignment: true, ..Self::NOTHING };
+
+    /// Assume only that lifetime conditions are met.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const LIFETIMES: Self = Self { lifetimes: true, ..Self::NOTHING };
+
+    /// Assume only that safety conditions are met.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const SAFETY: Self = Self { safety: true, ..Self::NOTHING };
+
+    /// Assume only that dynamically-satisfiable validity conditions are met.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const VALIDITY: Self = Self { validity: true, ..Self::NOTHING };
+
+    /// Assume both `self` and `other_assumptions`.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const fn and(self, other_assumptions: Self) -> Self {
+        Self {
+            alignment: self.alignment || other_assumptions.alignment,
+            lifetimes: self.lifetimes || other_assumptions.lifetimes,
+            safety: self.safety || other_assumptions.safety,
+            validity: self.validity || other_assumptions.validity,
+        }
+    }
+
+    /// Assume `self`, excepting `other_assumptions`.
+    #[unstable(feature = "transmutability", issue = "99571")]
+    pub const fn but_not(self, other_assumptions: Self) -> Self {
+        Self {
+            alignment: self.alignment && !other_assumptions.alignment,
+            lifetimes: self.lifetimes && !other_assumptions.lifetimes,
+            safety: self.safety && !other_assumptions.safety,
+            validity: self.validity && !other_assumptions.validity,
+        }
+    }
+}
+
+// FIXME(jswrenn): This const op is not actually usable. Why?
+// https://github.com/rust-lang/rust/pull/100726#issuecomment-1219928926
+#[unstable(feature = "transmutability", issue = "99571")]
+#[rustc_const_unstable(feature = "transmutability", issue = "99571")]
+impl const core::ops::Add for Assume {
+    type Output = Assume;
+
+    fn add(self, other_assumptions: Assume) -> Assume {
+        self.and(other_assumptions)
+    }
+}
+
+// FIXME(jswrenn): This const op is not actually usable. Why?
+// https://github.com/rust-lang/rust/pull/100726#issuecomment-1219928926
+#[unstable(feature = "transmutability", issue = "99571")]
+#[rustc_const_unstable(feature = "transmutability", issue = "99571")]
+impl const core::ops::Sub for Assume {
+    type Output = Assume;
+
+    fn sub(self, other_assumptions: Assume) -> Assume {
+        self.but_not(other_assumptions)
+    }
 }
diff --git a/library/core/src/mem/valid_align.rs b/library/core/src/mem/valid_align.rs
index b9ccc0b4c799..32b2afb72b0d 100644
--- a/library/core/src/mem/valid_align.rs
+++ b/library/core/src/mem/valid_align.rs
@@ -28,7 +28,7 @@ impl ValidAlign {
     #[inline]
     pub(crate) const unsafe fn new_unchecked(align: usize) -> Self {
         // SAFETY: Precondition passed to the caller.
-        unsafe { assert_unsafe_precondition!(align.is_power_of_two()) };
+        unsafe { assert_unsafe_precondition!((align: usize) => align.is_power_of_two()) };
 
         // SAFETY: By precondition, this must be a power of two, and
         // our variants encompass all possible powers of two.
diff --git a/library/core/src/num/dec2flt/decimal.rs b/library/core/src/num/dec2flt/decimal.rs
index f8edc3625e0a..2019f71e69b8 100644
--- a/library/core/src/num/dec2flt/decimal.rs
+++ b/library/core/src/num/dec2flt/decimal.rs
@@ -32,7 +32,7 @@ impl Default for Decimal {
 impl Decimal {
     /// The maximum number of digits required to unambiguously round a float.
     ///
-    /// For a double-precision IEEE-754 float, this required 767 digits,
+    /// For a double-precision IEEE 754 float, this required 767 digits,
     /// so we store the max digits + 1.
     ///
     /// We can exactly represent a float in radix `b` from radix 2 if
diff --git a/library/core/src/num/dec2flt/lemire.rs b/library/core/src/num/dec2flt/lemire.rs
index 75405f471541..b8b0a1d3d7e2 100644
--- a/library/core/src/num/dec2flt/lemire.rs
+++ b/library/core/src/num/dec2flt/lemire.rs
@@ -6,7 +6,7 @@ use crate::num::dec2flt::table::{
     LARGEST_POWER_OF_FIVE, POWER_OF_FIVE_128, SMALLEST_POWER_OF_FIVE,
 };
 
-/// Compute a float using an extended-precision representation.
+/// Compute w * 10^q using an extended-precision float representation.
 ///
 /// Fast conversion of a the significant digits and decimal exponent
 /// a float to an extended representation with a binary float. This
diff --git a/library/core/src/num/error.rs b/library/core/src/num/error.rs
index 1f6b40e5df55..768dd87816df 100644
--- a/library/core/src/num/error.rs
+++ b/library/core/src/num/error.rs
@@ -1,7 +1,6 @@
 //! Error types for conversion to integral types.
 
 use crate::convert::Infallible;
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 
@@ -147,7 +146,6 @@ impl fmt::Display for ParseIntError {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Error for ParseIntError {
     #[allow(deprecated)]
@@ -156,7 +154,6 @@ impl Error for ParseIntError {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "try_from", since = "1.34.0")]
 impl Error for TryFromIntError {
     #[allow(deprecated)]
diff --git a/library/core/src/num/f32.rs b/library/core/src/num/f32.rs
index da41ea536357..2c6a0ba64f26 100644
--- a/library/core/src/num/f32.rs
+++ b/library/core/src/num/f32.rs
@@ -394,7 +394,7 @@ impl f32 {
 
     /// Not a Number (NaN).
     ///
-    /// Note that IEEE-754 doesn't define just a single NaN value;
+    /// Note that IEEE 754 doesn't define just a single NaN value;
     /// a plethora of bit patterns are considered to be NaN.
     /// Furthermore, the standard makes a difference
     /// between a "signaling" and a "quiet" NaN,
@@ -632,7 +632,7 @@ impl f32 {
     }
 
     /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
-    /// positive sign bit and positive infinity. Note that IEEE-754 doesn't assign any
+    /// positive sign bit and positive infinity. Note that IEEE 754 doesn't assign any
     /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that
     /// the bit pattern of NaNs are conserved over arithmetic operations, the result of
     /// `is_sign_positive` on a NaN might produce an unexpected result in some cases.
@@ -654,7 +654,7 @@ impl f32 {
     }
 
     /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
-    /// negative sign bit and negative infinity. Note that IEEE-754 doesn't assign any
+    /// negative sign bit and negative infinity. Note that IEEE 754 doesn't assign any
     /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that
     /// the bit pattern of NaNs are conserved over arithmetic operations, the result of
     /// `is_sign_negative` on a NaN might produce an unexpected result in some cases.
@@ -833,7 +833,7 @@ impl f32 {
     /// Returns the maximum of the two numbers, ignoring NaN.
     ///
     /// If one of the arguments is NaN, then the other argument is returned.
-    /// This follows the IEEE-754 2008 semantics for maxNum, except for handling of signaling NaNs;
+    /// This follows the IEEE 754-2008 semantics for maxNum, except for handling of signaling NaNs;
     /// this function handles all NaNs the same way and avoids maxNum's problems with associativity.
     /// This also matches the behavior of libm’s fmax.
     ///
@@ -853,7 +853,7 @@ impl f32 {
     /// Returns the minimum of the two numbers, ignoring NaN.
     ///
     /// If one of the arguments is NaN, then the other argument is returned.
-    /// This follows the IEEE-754 2008 semantics for minNum, except for handling of signaling NaNs;
+    /// This follows the IEEE 754-2008 semantics for minNum, except for handling of signaling NaNs;
     /// this function handles all NaNs the same way and avoids minNum's problems with associativity.
     /// This also matches the behavior of libm’s fmin.
     ///
@@ -1033,10 +1033,14 @@ impl f32 {
                 }
             }
         }
-        // SAFETY: `u32` is a plain old datatype so we can always... uh...
-        // ...look, just pretend you forgot what you just read.
-        // Stability concerns.
-        let rt_f32_to_u32 = |rt| unsafe { mem::transmute::<f32, u32>(rt) };
+
+        #[inline(always)] // See https://github.com/rust-lang/compiler-builtins/issues/491
+        fn rt_f32_to_u32(x: f32) -> u32 {
+            // SAFETY: `u32` is a plain old datatype so we can always... uh...
+            // ...look, just pretend you forgot what you just read.
+            // Stability concerns.
+            unsafe { mem::transmute(x) }
+        }
         // SAFETY: We use internal implementations that either always work or fail at compile time.
         unsafe { intrinsics::const_eval_select((self,), ct_f32_to_u32, rt_f32_to_u32) }
     }
@@ -1047,9 +1051,9 @@ impl f32 {
     /// It turns out this is incredibly portable, for two reasons:
     ///
     /// * Floats and Ints have the same endianness on all supported platforms.
-    /// * IEEE-754 very precisely specifies the bit layout of floats.
+    /// * IEEE 754 very precisely specifies the bit layout of floats.
     ///
-    /// However there is one caveat: prior to the 2008 version of IEEE-754, how
+    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
     /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
     /// (notably x86 and ARM) picked the interpretation that was ultimately
     /// standardized in 2008, but some didn't (notably MIPS). As a result, all
@@ -1121,10 +1125,14 @@ impl f32 {
                 }
             }
         }
-        // SAFETY: `u32` is a plain old datatype so we can always... uh...
-        // ...look, just pretend you forgot what you just read.
-        // Stability concerns.
-        let rt_u32_to_f32 = |rt| unsafe { mem::transmute::<u32, f32>(rt) };
+
+        #[inline(always)] // See https://github.com/rust-lang/compiler-builtins/issues/491
+        fn rt_u32_to_f32(x: u32) -> f32 {
+            // SAFETY: `u32` is a plain old datatype so we can always... uh...
+            // ...look, just pretend you forgot what you just read.
+            // Stability concerns.
+            unsafe { mem::transmute(x) }
+        }
         // SAFETY: We use internal implementations that either always work or fail at compile time.
         unsafe { intrinsics::const_eval_select((v,), ct_u32_to_f32, rt_u32_to_f32) }
     }
diff --git a/library/core/src/num/f64.rs b/library/core/src/num/f64.rs
index 631d559df5f7..fd3c18ce29bd 100644
--- a/library/core/src/num/f64.rs
+++ b/library/core/src/num/f64.rs
@@ -393,7 +393,7 @@ impl f64 {
 
     /// Not a Number (NaN).
     ///
-    /// Note that IEEE-754 doesn't define just a single NaN value;
+    /// Note that IEEE 754 doesn't define just a single NaN value;
     /// a plethora of bit patterns are considered to be NaN.
     /// Furthermore, the standard makes a difference
     /// between a "signaling" and a "quiet" NaN,
@@ -624,7 +624,7 @@ impl f64 {
     }
 
     /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
-    /// positive sign bit and positive infinity. Note that IEEE-754 doesn't assign any
+    /// positive sign bit and positive infinity. Note that IEEE 754 doesn't assign any
     /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that
     /// the bit pattern of NaNs are conserved over arithmetic operations, the result of
     /// `is_sign_positive` on a NaN might produce an unexpected result in some cases.
@@ -655,7 +655,7 @@ impl f64 {
     }
 
     /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
-    /// negative sign bit and negative infinity. Note that IEEE-754 doesn't assign any
+    /// negative sign bit and negative infinity. Note that IEEE 754 doesn't assign any
     /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that
     /// the bit pattern of NaNs are conserved over arithmetic operations, the result of
     /// `is_sign_negative` on a NaN might produce an unexpected result in some cases.
@@ -844,7 +844,7 @@ impl f64 {
     /// Returns the maximum of the two numbers, ignoring NaN.
     ///
     /// If one of the arguments is NaN, then the other argument is returned.
-    /// This follows the IEEE-754 2008 semantics for maxNum, except for handling of signaling NaNs;
+    /// This follows the IEEE 754-2008 semantics for maxNum, except for handling of signaling NaNs;
     /// this function handles all NaNs the same way and avoids maxNum's problems with associativity.
     /// This also matches the behavior of libm’s fmax.
     ///
@@ -864,7 +864,7 @@ impl f64 {
     /// Returns the minimum of the two numbers, ignoring NaN.
     ///
     /// If one of the arguments is NaN, then the other argument is returned.
-    /// This follows the IEEE-754 2008 semantics for minNum, except for handling of signaling NaNs;
+    /// This follows the IEEE 754-2008 semantics for minNum, except for handling of signaling NaNs;
     /// this function handles all NaNs the same way and avoids minNum's problems with associativity.
     /// This also matches the behavior of libm’s fmin.
     ///
@@ -1026,10 +1026,14 @@ impl f64 {
                 }
             }
         }
-        // SAFETY: `u64` is a plain old datatype so we can always... uh...
-        // ...look, just pretend you forgot what you just read.
-        // Stability concerns.
-        let rt_f64_to_u64 = |rt| unsafe { mem::transmute::<f64, u64>(rt) };
+
+        #[inline(always)] // See https://github.com/rust-lang/compiler-builtins/issues/491
+        fn rt_f64_to_u64(rt: f64) -> u64 {
+            // SAFETY: `u64` is a plain old datatype so we can always... uh...
+            // ...look, just pretend you forgot what you just read.
+            // Stability concerns.
+            unsafe { mem::transmute::<f64, u64>(rt) }
+        }
         // SAFETY: We use internal implementations that either always work or fail at compile time.
         unsafe { intrinsics::const_eval_select((self,), ct_f64_to_u64, rt_f64_to_u64) }
     }
@@ -1040,9 +1044,9 @@ impl f64 {
     /// It turns out this is incredibly portable, for two reasons:
     ///
     /// * Floats and Ints have the same endianness on all supported platforms.
-    /// * IEEE-754 very precisely specifies the bit layout of floats.
+    /// * IEEE 754 very precisely specifies the bit layout of floats.
     ///
-    /// However there is one caveat: prior to the 2008 version of IEEE-754, how
+    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
     /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
     /// (notably x86 and ARM) picked the interpretation that was ultimately
     /// standardized in 2008, but some didn't (notably MIPS). As a result, all
@@ -1119,10 +1123,14 @@ impl f64 {
                 }
             }
         }
-        // SAFETY: `u64` is a plain old datatype so we can always... uh...
-        // ...look, just pretend you forgot what you just read.
-        // Stability concerns.
-        let rt_u64_to_f64 = |rt| unsafe { mem::transmute::<u64, f64>(rt) };
+
+        #[inline(always)] // See https://github.com/rust-lang/compiler-builtins/issues/491
+        fn rt_u64_to_f64(rt: u64) -> f64 {
+            // SAFETY: `u64` is a plain old datatype so we can always... uh...
+            // ...look, just pretend you forgot what you just read.
+            // Stability concerns.
+            unsafe { mem::transmute::<u64, f64>(rt) }
+        }
         // SAFETY: We use internal implementations that either always work or fail at compile time.
         unsafe { intrinsics::const_eval_select((v,), ct_u64_to_f64, rt_u64_to_f64) }
     }
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index 92b12ed33528..e7deb728d15d 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -1518,6 +1518,51 @@ macro_rules! int_impl {
             (a as Self, b)
         }
 
+        /// Calculates `self + rhs + carry` without the ability to overflow.
+        ///
+        /// Performs "signed ternary addition" which takes in an extra bit to add, and may return an
+        /// additional bit of overflow. This signed function is used only on the highest-ordered data,
+        /// for which the signed overflow result indicates whether the big integer overflowed or not.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// #![feature(bigint_helper_methods)]
+        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, false), (7, false));")]
+        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, true), (8, false));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, false), (", stringify!($SelfT), "::MIN, true));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(0, true), (", stringify!($SelfT), "::MIN, true));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, true), (", stringify!($SelfT), "::MIN + 1, true));")]
+        #[doc = concat!("assert_eq!(",
+            stringify!($SelfT), "::MAX.carrying_add(", stringify!($SelfT), "::MAX, true), ",
+            "(-1, true));"
+        )]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.carrying_add(-1, true), (", stringify!($SelfT), "::MIN, false));")]
+        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".carrying_add(", stringify!($SelfT), "::MAX, true), (", stringify!($SelfT), "::MIN, true));")]
+        /// ```
+        ///
+        /// If `carry` is false, this method is equivalent to [`overflowing_add`](Self::overflowing_add):
+        ///
+        /// ```
+        /// #![feature(bigint_helper_methods)]
+        #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".carrying_add(2, false), 5_", stringify!($SelfT), ".overflowing_add(2));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, false), ", stringify!($SelfT), "::MAX.overflowing_add(1));")]
+        /// ```
+        #[unstable(feature = "bigint_helper_methods", issue = "85532")]
+        #[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
+            // note: longer-term this should be done via an intrinsic.
+            // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
+            let (a, b) = self.overflowing_add(rhs);
+            let (c, d) = a.overflowing_add(carry as $SelfT);
+            (c, b != d)
+        }
+
         /// Calculates `self` + `rhs` with an unsigned `rhs`
         ///
         /// Returns a tuple of the addition along with a boolean indicating
@@ -1569,6 +1614,39 @@ macro_rules! int_impl {
             (a as Self, b)
         }
 
+        /// Calculates `self - rhs - borrow` without the ability to overflow.
+        ///
+        /// Performs "signed ternary subtraction" which takes in an extra bit to subtract, and may return an
+        /// additional bit of overflow. This signed function is used only on the highest-ordered data,
+        /// for which the signed overflow result indicates whether the big integer overflowed or not.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        ///
+        /// ```
+        /// #![feature(bigint_helper_methods)]
+        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, false), (3, false));")]
+        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, true), (2, false));")]
+        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".borrowing_sub(1, false), (-1, false));")]
+        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".borrowing_sub(1, true), (-2, false));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.borrowing_sub(1, true), (", stringify!($SelfT), "::MAX - 1, true));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.borrowing_sub(-1, false), (", stringify!($SelfT), "::MIN, true));")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.borrowing_sub(-1, true), (", stringify!($SelfT), "::MAX, false));")]
+        /// ```
+        #[unstable(feature = "bigint_helper_methods", issue = "85532")]
+        #[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
+            // note: longer-term this should be done via an intrinsic.
+            // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
+            let (a, b) = self.overflowing_sub(rhs);
+            let (c, d) = a.overflowing_sub(borrow as $SelfT);
+            (c, b != d)
+        }
+
         /// Calculates `self` - `rhs` with an unsigned `rhs`
         ///
         /// Returns a tuple of the subtraction along with a boolean indicating
diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
index ab17aa0c8303..c0be235c120b 100644
--- a/library/core/src/num/mod.rs
+++ b/library/core/src/num/mod.rs
@@ -3,7 +3,6 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 use crate::ascii;
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::intrinsics;
 use crate::mem;
@@ -59,7 +58,6 @@ pub use wrapping::Wrapping;
 #[cfg(not(no_fp_fmt_parse))]
 pub use dec2flt::ParseFloatError;
 
-#[cfg(not(bootstrap))]
 #[cfg(not(no_fp_fmt_parse))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Error for ParseFloatError {
@@ -113,6 +111,9 @@ macro_rules! widening_impl {
         /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
         /// of the result as two separate values, in that order.
         ///
+        /// If you also need to add a carry to the wide result, then you want
+        /// [`Self::carrying_mul`] instead.
+        ///
         /// # Examples
         ///
         /// Basic usage:
@@ -148,6 +149,8 @@ macro_rules! widening_impl {
         /// additional amount of overflow. This allows for chaining together multiple
         /// multiplications to create "big integers" which represent larger values.
         ///
+        /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead.
+        ///
         /// # Examples
         ///
         /// Basic usage:
@@ -167,6 +170,31 @@ macro_rules! widening_impl {
         )]
         /// ```
         ///
+        /// This is the core operation needed for scalar multiplication when
+        /// implementing it for wider-than-native types.
+        ///
+        /// ```
+        /// #![feature(bigint_helper_methods)]
+        /// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) {
+        ///     let mut carry = 0;
+        ///     for d in little_endian_digits.iter_mut() {
+        ///         (*d, carry) = d.carrying_mul(multiplicand, carry);
+        ///     }
+        ///     if carry != 0 {
+        ///         little_endian_digits.push(carry);
+        ///     }
+        /// }
+        ///
+        /// let mut v = vec![10, 20];
+        /// scalar_mul_eq(&mut v, 3);
+        /// assert_eq!(v, [30, 60]);
+        ///
+        /// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D);
+        /// let mut v = vec![0x4321, 0x8765];
+        /// scalar_mul_eq(&mut v, 0xFEED);
+        /// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]);
+        /// ```
+        ///
         /// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul),
         /// except that it gives the value of the overflow instead of just whether one happened:
         ///
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 6196c4da4e32..532a09736a7a 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -56,7 +56,7 @@ macro_rules! nonzero_integers {
                 pub const unsafe fn new_unchecked(n: $Int) -> Self {
                     // SAFETY: this is guaranteed to be safe by the caller.
                     unsafe {
-                        core::intrinsics::assert_unsafe_precondition!(n != 0);
+                        core::intrinsics::assert_unsafe_precondition!((n: $Int) => n != 0);
                         Self(n)
                     }
                 }
@@ -309,8 +309,8 @@ macro_rules! nonzero_unsigned_operations {
     ( $( $Ty: ident($Int: ident); )+ ) => {
         $(
             impl $Ty {
-                /// Add an unsigned integer to a non-zero value.
-                /// Check for overflow and return [`None`] on overflow
+                /// Adds an unsigned integer to a non-zero value.
+                /// Checks for overflow and returns [`None`] on overflow.
                 /// As a consequence, the result cannot wrap to zero.
                 ///
                 ///
@@ -346,7 +346,7 @@ macro_rules! nonzero_unsigned_operations {
                     }
                 }
 
-                /// Add an unsigned integer to a non-zero value.
+                /// Adds an unsigned integer to a non-zero value.
                 #[doc = concat!("Return [`", stringify!($Int), "::MAX`] on overflow.")]
                 ///
                 /// # Examples
@@ -377,7 +377,7 @@ macro_rules! nonzero_unsigned_operations {
                     unsafe { $Ty::new_unchecked(self.get().saturating_add(other)) }
                 }
 
-                /// Add an unsigned integer to a non-zero value,
+                /// Adds an unsigned integer to a non-zero value,
                 /// assuming overflow cannot occur.
                 /// Overflow is unchecked, and it is undefined behaviour to overflow
                 /// *even if the result would wrap to a non-zero value*.
@@ -409,7 +409,7 @@ macro_rules! nonzero_unsigned_operations {
                 }
 
                 /// Returns the smallest power of two greater than or equal to n.
-                /// Check for overflow and return [`None`]
+                /// Checks for overflow and returns [`None`]
                 /// if the next power of two is greater than the type’s maximum value.
                 /// As a consequence, the result cannot wrap to zero.
                 ///
@@ -545,7 +545,7 @@ macro_rules! nonzero_signed_operations {
                 }
 
                 /// Checked absolute value.
-                /// Check for overflow and returns [`None`] if
+                /// Checks for overflow and returns [`None`] if
                 #[doc = concat!("`self == ", stringify!($Int), "::MIN`.")]
                 /// The result cannot be zero.
                 ///
@@ -740,8 +740,8 @@ macro_rules! nonzero_unsigned_signed_operations {
     ( $( $signedness:ident $Ty: ident($Int: ty); )+ ) => {
         $(
             impl $Ty {
-                /// Multiply two non-zero integers together.
-                /// Check for overflow and return [`None`] on overflow.
+                /// Multiplies two non-zero integers together.
+                /// Checks for overflow and returns [`None`] on overflow.
                 /// As a consequence, the result cannot wrap to zero.
                 ///
                 /// # Examples
@@ -777,7 +777,7 @@ macro_rules! nonzero_unsigned_signed_operations {
                     }
                 }
 
-                /// Multiply two non-zero integers together.
+                /// Multiplies two non-zero integers together.
                 #[doc = concat!("Return [`", stringify!($Int), "::MAX`] on overflow.")]
                 ///
                 /// # Examples
@@ -809,7 +809,7 @@ macro_rules! nonzero_unsigned_signed_operations {
                     unsafe { $Ty::new_unchecked(self.get().saturating_mul(other.get())) }
                 }
 
-                /// Multiply two non-zero integers together,
+                /// Multiplies two non-zero integers together,
                 /// assuming overflow cannot occur.
                 /// Overflow is unchecked, and it is undefined behaviour to overflow
                 /// *even if the result would wrap to a non-zero value*.
@@ -849,8 +849,8 @@ macro_rules! nonzero_unsigned_signed_operations {
                     unsafe { $Ty::new_unchecked(self.get().unchecked_mul(other.get())) }
                 }
 
-                /// Raise non-zero value to an integer power.
-                /// Check for overflow and return [`None`] on overflow.
+                /// Raises non-zero value to an integer power.
+                /// Checks for overflow and returns [`None`] on overflow.
                 /// As a consequence, the result cannot wrap to zero.
                 ///
                 /// # Examples
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index aa3e8b9974ec..46fd7f2d0e49 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -688,7 +688,7 @@ macro_rules! uint_impl {
         /// rounded down.
         ///
         /// This method might not be optimized owing to implementation details;
-        /// `log2` can produce results more efficiently for base 2, and `log10`
+        /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
         /// can produce results more efficiently for base 10.
         ///
         /// # Panics
diff --git a/library/core/src/ops/arith.rs b/library/core/src/ops/arith.rs
index e367be8c167c..75c52d3ecfc8 100644
--- a/library/core/src/ops/arith.rs
+++ b/library/core/src/ops/arith.rs
@@ -65,38 +65,15 @@
 /// ```
 #[lang = "add"]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        on(
-            all(_Self = "{integer}", Rhs = "{float}"),
-            message = "cannot add a float to an integer",
-        ),
-        on(
-            all(_Self = "{float}", Rhs = "{integer}"),
-            message = "cannot add an integer to a float",
-        ),
-        message = "cannot add `{Rhs}` to `{Self}`",
-        label = "no implementation for `{Self} + {Rhs}`"
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        on(
-            all(_Self = "{integer}", Rhs = "{float}"),
-            message = "cannot add a float to an integer",
-        ),
-        on(
-            all(_Self = "{float}", Rhs = "{integer}"),
-            message = "cannot add an integer to a float",
-        ),
-        message = "cannot add `{Rhs}` to `{Self}`",
-        label = "no implementation for `{Self} + {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    on(all(_Self = "{integer}", Rhs = "{float}"), message = "cannot add a float to an integer",),
+    on(all(_Self = "{float}", Rhs = "{integer}"), message = "cannot add an integer to a float",),
+    message = "cannot add `{Rhs}` to `{Self}`",
+    label = "no implementation for `{Self} + {Rhs}`",
+    append_const_msg
 )]
 #[doc(alias = "+")]
+#[const_trait]
 pub trait Add<Rhs = Self> {
     /// The resulting type after applying the `+` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -201,9 +178,11 @@ add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(
     message = "cannot subtract `{Rhs}` from `{Self}`",
-    label = "no implementation for `{Self} - {Rhs}`"
+    label = "no implementation for `{Self} - {Rhs}`",
+    append_const_msg
 )]
 #[doc(alias = "-")]
+#[const_trait]
 pub trait Sub<Rhs = Self> {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -333,6 +312,7 @@ sub_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
     label = "no implementation for `{Self} * {Rhs}`"
 )]
 #[doc(alias = "*")]
+#[const_trait]
 pub trait Mul<Rhs = Self> {
     /// The resulting type after applying the `*` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -466,6 +446,7 @@ mul_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
     label = "no implementation for `{Self} / {Rhs}`"
 )]
 #[doc(alias = "/")]
+#[const_trait]
 pub trait Div<Rhs = Self> {
     /// The resulting type after applying the `/` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -568,6 +549,7 @@ div_impl_float! { f32 f64 }
     label = "no implementation for `{Self} % {Rhs}`"
 )]
 #[doc(alias = "%")]
+#[const_trait]
 pub trait Rem<Rhs = Self> {
     /// The resulting type after applying the `%` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -682,6 +664,7 @@ rem_impl_float! { f32 f64 }
 #[lang = "neg"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "-")]
+#[const_trait]
 pub trait Neg {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -755,6 +738,7 @@ neg_impl! { isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "+")]
 #[doc(alias = "+=")]
+#[const_trait]
 pub trait AddAssign<Rhs = Self> {
     /// Performs the `+=` operation.
     ///
@@ -822,6 +806,7 @@ add_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "-")]
 #[doc(alias = "-=")]
+#[const_trait]
 pub trait SubAssign<Rhs = Self> {
     /// Performs the `-=` operation.
     ///
@@ -880,6 +865,7 @@ sub_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "*")]
 #[doc(alias = "*=")]
+#[const_trait]
 pub trait MulAssign<Rhs = Self> {
     /// Performs the `*=` operation.
     ///
@@ -938,6 +924,7 @@ mul_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "/")]
 #[doc(alias = "/=")]
+#[const_trait]
 pub trait DivAssign<Rhs = Self> {
     /// Performs the `/=` operation.
     ///
@@ -999,6 +986,7 @@ div_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "%")]
 #[doc(alias = "%=")]
+#[const_trait]
 pub trait RemAssign<Rhs = Self> {
     /// Performs the `%=` operation.
     ///
diff --git a/library/core/src/ops/bit.rs b/library/core/src/ops/bit.rs
index 7c664226fc25..327009801d1b 100644
--- a/library/core/src/ops/bit.rs
+++ b/library/core/src/ops/bit.rs
@@ -31,6 +31,7 @@
 #[lang = "not"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "!")]
+#[const_trait]
 pub trait Not {
     /// The resulting type after applying the `!` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -143,6 +144,7 @@ impl const Not for ! {
     message = "no implementation for `{Self} & {Rhs}`",
     label = "no implementation for `{Self} & {Rhs}`"
 )]
+#[const_trait]
 pub trait BitAnd<Rhs = Self> {
     /// The resulting type after applying the `&` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -244,6 +246,7 @@ bitand_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} | {Rhs}`",
     label = "no implementation for `{Self} | {Rhs}`"
 )]
+#[const_trait]
 pub trait BitOr<Rhs = Self> {
     /// The resulting type after applying the `|` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -345,6 +348,7 @@ bitor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} ^ {Rhs}`",
     label = "no implementation for `{Self} ^ {Rhs}`"
 )]
+#[const_trait]
 pub trait BitXor<Rhs = Self> {
     /// The resulting type after applying the `^` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -445,6 +449,7 @@ bitxor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} << {Rhs}`",
     label = "no implementation for `{Self} << {Rhs}`"
 )]
+#[const_trait]
 pub trait Shl<Rhs = Self> {
     /// The resulting type after applying the `<<` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -564,6 +569,7 @@ shl_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 isize i128 }
     message = "no implementation for `{Self} >> {Rhs}`",
     label = "no implementation for `{Self} >> {Rhs}`"
 )]
+#[const_trait]
 pub trait Shr<Rhs = Self> {
     /// The resulting type after applying the `>>` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -692,6 +698,7 @@ shr_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} &= {Rhs}`",
     label = "no implementation for `{Self} &= {Rhs}`"
 )]
+#[const_trait]
 pub trait BitAndAssign<Rhs = Self> {
     /// Performs the `&=` operation.
     ///
@@ -764,6 +771,7 @@ bitand_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} |= {Rhs}`",
     label = "no implementation for `{Self} |= {Rhs}`"
 )]
+#[const_trait]
 pub trait BitOrAssign<Rhs = Self> {
     /// Performs the `|=` operation.
     ///
@@ -836,6 +844,7 @@ bitor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} ^= {Rhs}`",
     label = "no implementation for `{Self} ^= {Rhs}`"
 )]
+#[const_trait]
 pub trait BitXorAssign<Rhs = Self> {
     /// Performs the `^=` operation.
     ///
@@ -906,6 +915,7 @@ bitxor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} <<= {Rhs}`",
     label = "no implementation for `{Self} <<= {Rhs}`"
 )]
+#[const_trait]
 pub trait ShlAssign<Rhs = Self> {
     /// Performs the `<<=` operation.
     ///
@@ -989,6 +999,7 @@ shl_assign_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} >>= {Rhs}`",
     label = "no implementation for `{Self} >>= {Rhs}`"
 )]
+#[const_trait]
 pub trait ShrAssign<Rhs = Self> {
     /// Performs the `>>=` operation.
     ///
diff --git a/library/core/src/ops/control_flow.rs b/library/core/src/ops/control_flow.rs
index b1f5559dcfc1..72ebe653caff 100644
--- a/library/core/src/ops/control_flow.rs
+++ b/library/core/src/ops/control_flow.rs
@@ -95,7 +95,8 @@ pub enum ControlFlow<B, C = ()> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277")]
-impl<B, C> ops::Try for ControlFlow<B, C> {
+#[rustc_const_unstable(feature = "const_convert", issue = "88674")]
+impl<B, C> const ops::Try for ControlFlow<B, C> {
     type Output = C;
     type Residual = ControlFlow<B, convert::Infallible>;
 
@@ -114,7 +115,8 @@ impl<B, C> ops::Try for ControlFlow<B, C> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277")]
-impl<B, C> ops::FromResidual for ControlFlow<B, C> {
+#[rustc_const_unstable(feature = "const_convert", issue = "88674")]
+impl<B, C> const ops::FromResidual for ControlFlow<B, C> {
     #[inline]
     fn from_residual(residual: ControlFlow<B, convert::Infallible>) -> Self {
         match residual {
@@ -124,7 +126,8 @@ impl<B, C> ops::FromResidual for ControlFlow<B, C> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<B, C> ops::Residual<C> for ControlFlow<B, convert::Infallible> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<B, C> const ops::Residual<C> for ControlFlow<B, convert::Infallible> {
     type TryType = ControlFlow<B, C>;
 }
 
diff --git a/library/core/src/ops/deref.rs b/library/core/src/ops/deref.rs
index d68932402a41..4f4c99c4ad97 100644
--- a/library/core/src/ops/deref.rs
+++ b/library/core/src/ops/deref.rs
@@ -61,6 +61,7 @@
 #[doc(alias = "&*")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Deref"]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait Deref {
     /// The resulting type after dereferencing.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -169,6 +170,7 @@ impl<T: ?Sized> const Deref for &mut T {
 #[lang = "deref_mut"]
 #[doc(alias = "*")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait DerefMut: Deref {
     /// Mutably dereferences the value.
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/src/ops/drop.rs b/library/core/src/ops/drop.rs
index de9ddb852df3..a2c3d978cc4f 100644
--- a/library/core/src/ops/drop.rs
+++ b/library/core/src/ops/drop.rs
@@ -134,6 +134,7 @@
 /// these types cannot have destructors.
 #[lang = "drop"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait Drop {
     /// Executes the destructor for this type.
     ///
diff --git a/library/core/src/ops/function.rs b/library/core/src/ops/function.rs
index c5a194b7d0a4..2e0a752c815d 100644
--- a/library/core/src/ops/function.rs
+++ b/library/core/src/ops/function.rs
@@ -71,6 +71,7 @@
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
 #[must_use = "closures are lazy and do nothing unless called"]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait Fn<Args>: FnMut<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
@@ -158,6 +159,7 @@ pub trait Fn<Args>: FnMut<Args> {
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
 #[must_use = "closures are lazy and do nothing unless called"]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait FnMut<Args>: FnOnce<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
@@ -237,6 +239,7 @@ pub trait FnMut<Args>: FnOnce<Args> {
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
 #[must_use = "closures are lazy and do nothing unless called"]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait FnOnce<Args> {
     /// The returned type after the call operator is used.
     #[lang = "fn_once_output"]
@@ -250,9 +253,10 @@ pub trait FnOnce<Args> {
 
 mod impls {
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl<A, F: ?Sized> Fn<A> for &F
+    #[rustc_const_unstable(feature = "const_fn_trait_ref_impls", issue = "101803")]
+    impl<A, F: ?Sized> const Fn<A> for &F
     where
-        F: Fn<A>,
+        F: ~const Fn<A>,
     {
         extern "rust-call" fn call(&self, args: A) -> F::Output {
             (**self).call(args)
@@ -260,9 +264,10 @@ mod impls {
     }
 
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl<A, F: ?Sized> FnMut<A> for &F
+    #[rustc_const_unstable(feature = "const_fn_trait_ref_impls", issue = "101803")]
+    impl<A, F: ?Sized> const FnMut<A> for &F
     where
-        F: Fn<A>,
+        F: ~const Fn<A>,
     {
         extern "rust-call" fn call_mut(&mut self, args: A) -> F::Output {
             (**self).call(args)
@@ -270,9 +275,10 @@ mod impls {
     }
 
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl<A, F: ?Sized> FnOnce<A> for &F
+    #[rustc_const_unstable(feature = "const_fn_trait_ref_impls", issue = "101803")]
+    impl<A, F: ?Sized> const FnOnce<A> for &F
     where
-        F: Fn<A>,
+        F: ~const Fn<A>,
     {
         type Output = F::Output;
 
@@ -282,9 +288,10 @@ mod impls {
     }
 
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl<A, F: ?Sized> FnMut<A> for &mut F
+    #[rustc_const_unstable(feature = "const_fn_trait_ref_impls", issue = "101803")]
+    impl<A, F: ?Sized> const FnMut<A> for &mut F
     where
-        F: FnMut<A>,
+        F: ~const FnMut<A>,
     {
         extern "rust-call" fn call_mut(&mut self, args: A) -> F::Output {
             (*self).call_mut(args)
@@ -292,9 +299,10 @@ mod impls {
     }
 
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl<A, F: ?Sized> FnOnce<A> for &mut F
+    #[rustc_const_unstable(feature = "const_fn_trait_ref_impls", issue = "101803")]
+    impl<A, F: ?Sized> const FnOnce<A> for &mut F
     where
-        F: FnMut<A>,
+        F: ~const FnMut<A>,
     {
         type Output = F::Output;
         extern "rust-call" fn call_once(self, args: A) -> F::Output {
diff --git a/library/core/src/ops/generator.rs b/library/core/src/ops/generator.rs
index b651b7b233ed..fee4beb1e84b 100644
--- a/library/core/src/ops/generator.rs
+++ b/library/core/src/ops/generator.rs
@@ -83,7 +83,6 @@ pub trait Generator<R = ()> {
     /// `return` statement or implicitly as the last expression of a generator
     /// literal. For example futures would use this as `Result<T, E>` as it
     /// represents a completed future.
-    #[lang = "generator_return"]
     type Return;
 
     /// Resumes the execution of this generator.
diff --git a/library/core/src/ops/index.rs b/library/core/src/ops/index.rs
index e2e569cb7ea8..dd4e3ac1c2fe 100644
--- a/library/core/src/ops/index.rs
+++ b/library/core/src/ops/index.rs
@@ -55,6 +55,7 @@
 #[doc(alias = "]")]
 #[doc(alias = "[")]
 #[doc(alias = "[]")]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait Index<Idx: ?Sized> {
     /// The returned type after indexing.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -163,6 +164,7 @@ see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#ind
 #[doc(alias = "[")]
 #[doc(alias = "]")]
 #[doc(alias = "[]")]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
     /// Performs the mutable indexing (`container[index]`) operation.
     ///
diff --git a/library/core/src/ops/index_range.rs b/library/core/src/ops/index_range.rs
new file mode 100644
index 000000000000..41ffe11f610d
--- /dev/null
+++ b/library/core/src/ops/index_range.rs
@@ -0,0 +1,166 @@
+use crate::intrinsics::{assert_unsafe_precondition, unchecked_add, unchecked_sub};
+use crate::iter::{FusedIterator, TrustedLen};
+
+/// Like a `Range<usize>`, but with a safety invariant that `start <= end`.
+///
+/// This means that `end - start` cannot overflow, allowing some μoptimizations.
+///
+/// (Normal `Range` code needs to handle degenerate ranges like `10..0`,
+///  which takes extra checks compared to only handling the canonical form.)
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub(crate) struct IndexRange {
+    start: usize,
+    end: usize,
+}
+
+impl IndexRange {
+    /// # Safety
+    /// - `start <= end`
+    #[inline]
+    pub const unsafe fn new_unchecked(start: usize, end: usize) -> Self {
+        // SAFETY: comparisons on usize are pure
+        unsafe { assert_unsafe_precondition!((start: usize, end: usize) => start <= end) };
+        IndexRange { start, end }
+    }
+
+    #[inline]
+    pub const fn zero_to(end: usize) -> Self {
+        IndexRange { start: 0, end }
+    }
+
+    #[inline]
+    pub const fn start(&self) -> usize {
+        self.start
+    }
+
+    #[inline]
+    pub const fn end(&self) -> usize {
+        self.end
+    }
+
+    #[inline]
+    pub const fn len(&self) -> usize {
+        // SAFETY: By invariant, this cannot wrap
+        unsafe { unchecked_sub(self.end, self.start) }
+    }
+
+    /// # Safety
+    /// - Can only be called when `start < end`, aka when `len > 0`.
+    #[inline]
+    unsafe fn next_unchecked(&mut self) -> usize {
+        debug_assert!(self.start < self.end);
+
+        let value = self.start;
+        // SAFETY: The range isn't empty, so this cannot overflow
+        self.start = unsafe { unchecked_add(value, 1) };
+        value
+    }
+
+    /// # Safety
+    /// - Can only be called when `start < end`, aka when `len > 0`.
+    #[inline]
+    unsafe fn next_back_unchecked(&mut self) -> usize {
+        debug_assert!(self.start < self.end);
+
+        // SAFETY: The range isn't empty, so this cannot overflow
+        let value = unsafe { unchecked_sub(self.end, 1) };
+        self.end = value;
+        value
+    }
+
+    /// Removes the first `n` items from this range, returning them as an `IndexRange`.
+    /// If there are fewer than `n`, then the whole range is returned and
+    /// `self` is left empty.
+    ///
+    /// This is designed to help implement `Iterator::advance_by`.
+    #[inline]
+    pub fn take_prefix(&mut self, n: usize) -> Self {
+        let mid = if n <= self.len() {
+            // SAFETY: We just checked that this will be between start and end,
+            // and thus the addition cannot overflow.
+            unsafe { unchecked_add(self.start, n) }
+        } else {
+            self.end
+        };
+        let prefix = Self { start: self.start, end: mid };
+        self.start = mid;
+        prefix
+    }
+
+    /// Removes the last `n` items from this range, returning them as an `IndexRange`.
+    /// If there are fewer than `n`, then the whole range is returned and
+    /// `self` is left empty.
+    ///
+    /// This is designed to help implement `Iterator::advance_back_by`.
+    #[inline]
+    pub fn take_suffix(&mut self, n: usize) -> Self {
+        let mid = if n <= self.len() {
+            // SAFETY: We just checked that this will be between start and end,
+            // and thus the addition cannot overflow.
+            unsafe { unchecked_sub(self.end, n) }
+        } else {
+            self.start
+        };
+        let suffix = Self { start: mid, end: self.end };
+        self.end = mid;
+        suffix
+    }
+}
+
+impl Iterator for IndexRange {
+    type Item = usize;
+
+    #[inline]
+    fn next(&mut self) -> Option<usize> {
+        if self.len() > 0 {
+            // SAFETY: We just checked that the range is non-empty
+            unsafe { Some(self.next_unchecked()) }
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len();
+        (len, Some(len))
+    }
+
+    #[inline]
+    fn advance_by(&mut self, n: usize) -> Result<(), usize> {
+        let original_len = self.len();
+        self.take_prefix(n);
+        if n > original_len { Err(original_len) } else { Ok(()) }
+    }
+}
+
+impl DoubleEndedIterator for IndexRange {
+    #[inline]
+    fn next_back(&mut self) -> Option<usize> {
+        if self.len() > 0 {
+            // SAFETY: We just checked that the range is non-empty
+            unsafe { Some(self.next_back_unchecked()) }
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
+        let original_len = self.len();
+        self.take_suffix(n);
+        if n > original_len { Err(original_len) } else { Ok(()) }
+    }
+}
+
+impl ExactSizeIterator for IndexRange {
+    #[inline]
+    fn len(&self) -> usize {
+        self.len()
+    }
+}
+
+// SAFETY: Because we only deal in `usize`, our `len` is always perfect.
+unsafe impl TrustedLen for IndexRange {}
+
+impl FusedIterator for IndexRange {}
diff --git a/library/core/src/ops/mod.rs b/library/core/src/ops/mod.rs
index 31c1a1d099dc..a5e5b13b3367 100644
--- a/library/core/src/ops/mod.rs
+++ b/library/core/src/ops/mod.rs
@@ -146,6 +146,7 @@ mod drop;
 mod function;
 mod generator;
 mod index;
+mod index_range;
 mod range;
 mod try_trait;
 mod unsize;
@@ -178,6 +179,8 @@ pub use self::index::{Index, IndexMut};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::range::{Range, RangeFrom, RangeFull, RangeTo};
 
+pub(crate) use self::index_range::IndexRange;
+
 #[stable(feature = "inclusive_range", since = "1.26.0")]
 pub use self::range::{Bound, RangeBounds, RangeInclusive, RangeToInclusive};
 
diff --git a/library/core/src/ops/range.rs b/library/core/src/ops/range.rs
index a3b14847342c..d29ae35614c1 100644
--- a/library/core/src/ops/range.rs
+++ b/library/core/src/ops/range.rs
@@ -677,7 +677,7 @@ pub enum Bound<T> {
 impl<T> Bound<T> {
     /// Converts from `&Bound<T>` to `Bound<&T>`.
     #[inline]
-    #[unstable(feature = "bound_as_ref", issue = "80996")]
+    #[stable(feature = "bound_as_ref_shared", since = "1.65.0")]
     pub fn as_ref(&self) -> Bound<&T> {
         match *self {
             Included(ref x) => Included(x),
diff --git a/library/core/src/ops/try_trait.rs b/library/core/src/ops/try_trait.rs
index 02f7f62bfe22..33df9e6c5cd4 100644
--- a/library/core/src/ops/try_trait.rs
+++ b/library/core/src/ops/try_trait.rs
@@ -128,7 +128,8 @@ use crate::ops::ControlFlow;
 )]
 #[doc(alias = "?")]
 #[lang = "Try"]
-pub trait Try: FromResidual {
+#[const_trait]
+pub trait Try: ~const FromResidual {
     /// The type of the value produced by `?` when *not* short-circuiting.
     #[unstable(feature = "try_trait_v2", issue = "84277")]
     type Output;
@@ -232,7 +233,7 @@ pub trait Try: FromResidual {
         message = "the `?` operator can only be used on `Result`s, not `Option`s, \
             in {ItemContext} that returns `Result`",
         label = "use `.ok_or(...)?` to provide an error compatible with `{Self}`",
-        enclosing_scope = "this function returns a `Result`"
+        parent_label = "this function returns a `Result`"
     ),
     on(
         all(
@@ -245,7 +246,7 @@ pub trait Try: FromResidual {
         message = "the `?` operator can only be used on `Result`s \
             in {ItemContext} that returns `Result`",
         label = "this `?` produces `{R}`, which is incompatible with `{Self}`",
-        enclosing_scope = "this function returns a `Result`"
+        parent_label = "this function returns a `Result`"
     ),
     on(
         all(
@@ -256,7 +257,7 @@ pub trait Try: FromResidual {
         message = "the `?` operator can only be used on `Option`s, not `Result`s, \
             in {ItemContext} that returns `Option`",
         label = "use `.ok()?` if you want to discard the `{R}` error information",
-        enclosing_scope = "this function returns an `Option`"
+        parent_label = "this function returns an `Option`"
     ),
     on(
         all(
@@ -268,7 +269,7 @@ pub trait Try: FromResidual {
         message = "the `?` operator can only be used on `Option`s \
             in {ItemContext} that returns `Option`",
         label = "this `?` produces `{R}`, which is incompatible with `{Self}`",
-        enclosing_scope = "this function returns an `Option`"
+        parent_label = "this function returns an `Option`"
     ),
     on(
         all(
@@ -279,7 +280,7 @@ pub trait Try: FromResidual {
         message = "the `?` operator in {ItemContext} that returns `ControlFlow<B, _>` \
             can only be used on other `ControlFlow<B, _>`s (with the same Break type)",
         label = "this `?` produces `{R}`, which is incompatible with `{Self}`",
-        enclosing_scope = "this function returns a `ControlFlow`",
+        parent_label = "this function returns a `ControlFlow`",
         note = "unlike `Result`, there's no `From`-conversion performed for `ControlFlow`"
     ),
     on(
@@ -291,7 +292,7 @@ pub trait Try: FromResidual {
         message = "the `?` operator can only be used on `ControlFlow`s \
             in {ItemContext} that returns `ControlFlow`",
         label = "this `?` produces `{R}`, which is incompatible with `{Self}`",
-        enclosing_scope = "this function returns a `ControlFlow`",
+        parent_label = "this function returns a `ControlFlow`",
     ),
     on(
         all(from_desugaring = "QuestionMark"),
@@ -299,11 +300,12 @@ pub trait Try: FromResidual {
                     that returns `Result` or `Option` \
                     (or another type that implements `{FromResidual}`)",
         label = "cannot use the `?` operator in {ItemContext} that returns `{Self}`",
-        enclosing_scope = "this function should return `Result` or `Option` to accept `?`"
+        parent_label = "this function should return `Result` or `Option` to accept `?`"
     ),
 )]
 #[rustc_diagnostic_item = "FromResidual"]
 #[unstable(feature = "try_trait_v2", issue = "84277")]
+#[const_trait]
 pub trait FromResidual<R = <Self as Try>::Residual> {
     /// Constructs the type from a compatible `Residual` type.
     ///
@@ -356,10 +358,11 @@ where
 /// and in the other direction,
 /// `<Result<Infallible, E> as Residual<T>>::TryType = Result<T, E>`.
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
+#[const_trait]
 pub trait Residual<O> {
     /// The "return" type of this meta-function.
     #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-    type TryType: Try<Output = O, Residual = Self>;
+    type TryType: ~const Try<Output = O, Residual = Self>;
 }
 
 #[unstable(feature = "pub_crate_should_not_need_unstable_attr", issue = "none")]
@@ -378,14 +381,17 @@ pub(crate) struct NeverShortCircuit<T>(pub T);
 impl<T> NeverShortCircuit<T> {
     /// Wrap a binary `FnMut` to return its result wrapped in a `NeverShortCircuit`.
     #[inline]
-    pub fn wrap_mut_2<A, B>(mut f: impl FnMut(A, B) -> T) -> impl FnMut(A, B) -> Self {
-        move |a, b| NeverShortCircuit(f(a, b))
+    pub const fn wrap_mut_2_imp<A, B, F: ~const FnMut(A, B) -> T>(
+        f: &mut F,
+        (a, b): (A, B),
+    ) -> NeverShortCircuit<T> {
+        NeverShortCircuit(f(a, b))
     }
 }
 
 pub(crate) enum NeverShortCircuitResidual {}
 
-impl<T> Try for NeverShortCircuit<T> {
+impl<T> const Try for NeverShortCircuit<T> {
     type Output = T;
     type Residual = NeverShortCircuitResidual;
 
@@ -400,14 +406,14 @@ impl<T> Try for NeverShortCircuit<T> {
     }
 }
 
-impl<T> FromResidual for NeverShortCircuit<T> {
+impl<T> const FromResidual for NeverShortCircuit<T> {
     #[inline]
     fn from_residual(never: NeverShortCircuitResidual) -> Self {
         match never {}
     }
 }
 
-impl<T> Residual<T> for NeverShortCircuitResidual {
+impl<T> const Residual<T> for NeverShortCircuitResidual {
     type TryType = NeverShortCircuit<T>;
 }
 
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 934175863630..ed7703befcfa 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -842,6 +842,7 @@ impl<T> Option<T> {
     /// ```
     /// let good_year_from_input = "1909";
     /// let bad_year_from_input = "190blarg";
+    /// // Result::ok() converts a Result<T> to an Option<T>
     /// let good_year = good_year_from_input.parse().ok().unwrap_or_default();
     /// let bad_year = bad_year_from_input.parse().ok().unwrap_or_default();
     ///
@@ -2321,7 +2322,8 @@ impl<T> ops::FromResidual<ops::Yeet<()>> for Option<T> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<T> ops::Residual<T> for Option<convert::Infallible> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const ops::Residual<T> for Option<convert::Infallible> {
     type TryType = Option<T>;
 }
 
diff --git a/library/core/src/primitive_docs.rs b/library/core/src/primitive_docs.rs
index 242f44ade8a2..331714a993c6 100644
--- a/library/core/src/primitive_docs.rs
+++ b/library/core/src/primitive_docs.rs
@@ -611,7 +611,19 @@ mod prim_pointer {}
 ///
 /// Arrays coerce to [slices (`[T]`)][slice], so a slice method may be called on
 /// an array. Indeed, this provides most of the API for working with arrays.
-/// Slices have a dynamic size and do not coerce to arrays.
+///
+/// Slices have a dynamic size and do not coerce to arrays. Instead, use
+/// `slice.try_into().unwrap()` or `<ArrayType>::try_from(slice).unwrap()`.
+///
+/// Array's `try_from(slice)` implementations (and the corresponding `slice.try_into()`
+/// array implementations) succeed if the input slice length is the same as the result
+/// array length. They optimize especially well when the optimizer can easily determine
+/// the slice length, e.g. `<[u8; 4]>::try_from(&slice[4..8]).unwrap()`. Array implements
+/// [TryFrom](crate::convert::TryFrom) returning:
+///
+/// - `[T; N]` copies from the slice's elements
+/// - `&[T; N]` references the original slice's elements
+/// - `&mut [T; N]` references the original slice's elements
 ///
 /// You can move elements out of an array with a [slice pattern]. If you want
 /// one element, see [`mem::replace`].
@@ -640,6 +652,15 @@ mod prim_pointer {}
 /// for x in &array { }
 /// ```
 ///
+/// You can use `<ArrayType>::try_from(slice)` or `slice.try_into()` to get an array from
+/// a slice:
+///
+/// ```
+/// let bytes: [u8; 3] = [1, 0, 2];
+/// assert_eq!(1, u16::from_le_bytes(<[u8; 2]>::try_from(&bytes[0..2]).unwrap()));
+/// assert_eq!(512, u16::from_le_bytes(bytes[1..3].try_into().unwrap()));
+/// ```
+///
 /// You can use a [slice pattern] to move elements out of an array:
 ///
 /// ```
diff --git a/library/core/src/ptr/const_ptr.rs b/library/core/src/ptr/const_ptr.rs
index ef7b3b1d1470..d898108be580 100644
--- a/library/core/src/ptr/const_ptr.rs
+++ b/library/core/src/ptr/const_ptr.rs
@@ -36,7 +36,10 @@ impl<T: ?Sized> *const T {
     pub const fn is_null(self) -> bool {
         // Compare via a cast to a thin pointer, so fat pointers are only
         // considering their "data" part for null-ness.
-        (self as *const u8).guaranteed_eq(null())
+        match (self as *const u8).guaranteed_eq(null()) {
+            None => false,
+            Some(res) => res,
+        }
     }
 
     /// Casts to a pointer of another type.
@@ -95,8 +98,8 @@ impl<T: ?Sized> *const T {
     ///
     /// This is a bit safer than `as` because it wouldn't silently change the type if the code is
     /// refactored.
-    #[stable(feature = "ptr_const_cast", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "ptr_const_cast", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "ptr_const_cast", since = "1.65.0")]
+    #[rustc_const_stable(feature = "ptr_const_cast", since = "1.65.0")]
     pub const fn cast_mut(self) -> *mut T {
         self as _
     }
@@ -154,7 +157,7 @@ impl<T: ?Sized> *const T {
     /// This is similar to `self as usize`, which semantically discards *provenance* and
     /// *address-space* information. However, unlike `self as usize`, casting the returned address
     /// back to a pointer yields [`invalid`][], which is undefined behavior to dereference. To
-    /// properly restore the lost information and obtain a dereferencable pointer, use
+    /// properly restore the lost information and obtain a dereferenceable pointer, use
     /// [`with_addr`][pointer::with_addr] or [`map_addr`][pointer::map_addr].
     ///
     /// If using those APIs is not possible because there is no way to preserve a pointer with the
@@ -565,7 +568,6 @@ impl<T: ?Sized> *const T {
     ///
     /// For non-`Sized` pointees this operation changes only the data pointer,
     /// leaving the metadata untouched.
-    #[cfg(not(bootstrap))]
     #[unstable(feature = "ptr_mask", issue = "98290")]
     #[must_use = "returns a new pointer rather than modifying its argument"]
     #[inline(always)]
@@ -755,9 +757,12 @@ impl<T: ?Sized> *const T {
     where
         T: Sized,
     {
+        let this = self;
         // SAFETY: The comparison has no side-effects, and the intrinsic
         // does this check internally in the CTFE implementation.
-        unsafe { assert_unsafe_precondition!(self >= origin) };
+        unsafe {
+            assert_unsafe_precondition!([T](this: *const T, origin: *const T) => this >= origin)
+        };
 
         let pointee_size = mem::size_of::<T>();
         assert!(0 < pointee_size && pointee_size <= isize::MAX as usize);
@@ -767,20 +772,16 @@ impl<T: ?Sized> *const T {
 
     /// Returns whether two pointers are guaranteed to be equal.
     ///
-    /// At runtime this function behaves like `self == other`.
+    /// At runtime this function behaves like `Some(self == other)`.
     /// However, in some contexts (e.g., compile-time evaluation),
     /// it is not always possible to determine equality of two pointers, so this function may
-    /// spuriously return `false` for pointers that later actually turn out to be equal.
-    /// But when it returns `true`, the pointers are guaranteed to be equal.
+    /// spuriously return `None` for pointers that later actually turn out to have its equality known.
+    /// But when it returns `Some`, the pointers' equality is guaranteed to be known.
     ///
-    /// This function is the mirror of [`guaranteed_ne`], but not its inverse. There are pointer
-    /// comparisons for which both functions return `false`.
-    ///
-    /// [`guaranteed_ne`]: #method.guaranteed_ne
-    ///
-    /// The return value may change depending on the compiler version and unsafe code must not
+    /// The return value may change from `Some` to `None` and vice versa depending on the compiler
+    /// version and unsafe code must not
     /// rely on the result of this function for soundness. It is suggested to only use this function
-    /// for performance optimizations where spurious `false` return values by this function do not
+    /// for performance optimizations where spurious `None` return values by this function do not
     /// affect the outcome, but just the performance.
     /// The consequences of using this method to make runtime and compile-time code behave
     /// differently have not been explored. This method should not be used to introduce such
@@ -789,29 +790,28 @@ impl<T: ?Sized> *const T {
     #[unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[inline]
-    pub const fn guaranteed_eq(self, other: *const T) -> bool
+    pub const fn guaranteed_eq(self, other: *const T) -> Option<bool>
     where
         T: Sized,
     {
-        intrinsics::ptr_guaranteed_eq(self, other)
+        match intrinsics::ptr_guaranteed_cmp(self as _, other as _) {
+            2 => None,
+            other => Some(other == 1),
+        }
     }
 
-    /// Returns whether two pointers are guaranteed to be unequal.
+    /// Returns whether two pointers are guaranteed to be inequal.
     ///
-    /// At runtime this function behaves like `self != other`.
+    /// At runtime this function behaves like `Some(self == other)`.
     /// However, in some contexts (e.g., compile-time evaluation),
-    /// it is not always possible to determine the inequality of two pointers, so this function may
-    /// spuriously return `false` for pointers that later actually turn out to be unequal.
-    /// But when it returns `true`, the pointers are guaranteed to be unequal.
+    /// it is not always possible to determine inequality of two pointers, so this function may
+    /// spuriously return `None` for pointers that later actually turn out to have its inequality known.
+    /// But when it returns `Some`, the pointers' inequality is guaranteed to be known.
     ///
-    /// This function is the mirror of [`guaranteed_eq`], but not its inverse. There are pointer
-    /// comparisons for which both functions return `false`.
-    ///
-    /// [`guaranteed_eq`]: #method.guaranteed_eq
-    ///
-    /// The return value may change depending on the compiler version and unsafe code must not
+    /// The return value may change from `Some` to `None` and vice versa depending on the compiler
+    /// version and unsafe code must not
     /// rely on the result of this function for soundness. It is suggested to only use this function
-    /// for performance optimizations where spurious `false` return values by this function do not
+    /// for performance optimizations where spurious `None` return values by this function do not
     /// affect the outcome, but just the performance.
     /// The consequences of using this method to make runtime and compile-time code behave
     /// differently have not been explored. This method should not be used to introduce such
@@ -820,11 +820,14 @@ impl<T: ?Sized> *const T {
     #[unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[inline]
-    pub const fn guaranteed_ne(self, other: *const T) -> bool
+    pub const fn guaranteed_ne(self, other: *const T) -> Option<bool>
     where
         T: Sized,
     {
-        intrinsics::ptr_guaranteed_ne(self, other)
+        match self.guaranteed_eq(other) {
+            None => None,
+            Some(eq) => Some(!eq),
+        }
     }
 
     /// Calculates the offset from a pointer (convenience for `.offset(count as isize)`).
diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs
index 203531f66aa3..e976abed774b 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -90,7 +90,7 @@
 //! isn't *pointer*-sized but address-space/offset/allocation-sized (we'll probably continue
 //! to conflate these notions). This would potentially make it possible to more efficiently
 //! target platforms where pointers are larger than offsets, such as CHERI and maybe some
-//! segmented architecures.
+//! segmented architectures.
 //!
 //! ## Provenance
 //!
@@ -172,7 +172,7 @@
 //! a pointer to a usize is generally an operation which *only* extracts the address. It is
 //! therefore *impossible* to construct a valid pointer from a usize because there is no way
 //! to restore the address-space and provenance. In other words, pointer-integer-pointer
-//! roundtrips are not possible (in the sense that the resulting pointer is not dereferencable).
+//! roundtrips are not possible (in the sense that the resulting pointer is not dereferenceable).
 //!
 //! The key insight to making this model *at all* viable is the [`with_addr`][] method:
 //!
@@ -272,7 +272,7 @@
 //!
 //! * Create an invalid pointer from just an address (see [`ptr::invalid`][]). This can
 //!   be used for sentinel values like `null` *or* to represent a tagged pointer that will
-//!   never be dereferencable. In general, it is always sound for an integer to pretend
+//!   never be dereferenceable. In general, it is always sound for an integer to pretend
 //!   to be a pointer "for fun" as long as you don't use operations on it which require
 //!   it to be valid (offset, read, write, etc).
 //!
@@ -886,7 +886,7 @@ pub const unsafe fn swap_nonoverlapping<T>(x: *mut T, y: *mut T, count: usize) {
     // SAFETY: the caller must guarantee that `x` and `y` are
     // valid for writes and properly aligned.
     unsafe {
-        assert_unsafe_precondition!(
+        assert_unsafe_precondition!([T](x: *mut T, y: *mut T, count: usize) =>
             is_aligned_and_not_null(x)
                 && is_aligned_and_not_null(y)
                 && is_nonoverlapping(x, y, count)
@@ -983,7 +983,7 @@ pub const unsafe fn replace<T>(dst: *mut T, mut src: T) -> T {
     // and cannot overlap `src` since `dst` must point to a distinct
     // allocated object.
     unsafe {
-        assert_unsafe_precondition!(is_aligned_and_not_null(dst));
+        assert_unsafe_precondition!([T](dst: *mut T) => is_aligned_and_not_null(dst));
         mem::swap(&mut *dst, &mut src); // cannot overlap
     }
     src
@@ -1470,7 +1470,7 @@ pub const unsafe fn write_unaligned<T>(dst: *mut T, src: T) {
 pub unsafe fn read_volatile<T>(src: *const T) -> T {
     // SAFETY: the caller must uphold the safety contract for `volatile_load`.
     unsafe {
-        assert_unsafe_precondition!(is_aligned_and_not_null(src));
+        assert_unsafe_precondition!([T](src: *const T) => is_aligned_and_not_null(src));
         intrinsics::volatile_load(src)
     }
 }
@@ -1541,7 +1541,7 @@ pub unsafe fn read_volatile<T>(src: *const T) -> T {
 pub unsafe fn write_volatile<T>(dst: *mut T, src: T) {
     // SAFETY: the caller must uphold the safety contract for `volatile_store`.
     unsafe {
-        assert_unsafe_precondition!(is_aligned_and_not_null(dst));
+        assert_unsafe_precondition!([T](dst: *mut T) => is_aligned_and_not_null(dst));
         intrinsics::volatile_store(dst, src);
     }
 }
diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs
index 6a3b9ee9a7da..543ab826c4eb 100644
--- a/library/core/src/ptr/mut_ptr.rs
+++ b/library/core/src/ptr/mut_ptr.rs
@@ -35,7 +35,10 @@ impl<T: ?Sized> *mut T {
     pub const fn is_null(self) -> bool {
         // Compare via a cast to a thin pointer, so fat pointers are only
         // considering their "data" part for null-ness.
-        (self as *mut u8).guaranteed_eq(null_mut())
+        match (self as *mut u8).guaranteed_eq(null_mut()) {
+            None => false,
+            Some(res) => res,
+        }
     }
 
     /// Casts to a pointer of another type.
@@ -100,8 +103,8 @@ impl<T: ?Sized> *mut T {
     /// coercion.
     ///
     /// [`cast_mut`]: #method.cast_mut
-    #[stable(feature = "ptr_const_cast", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "ptr_const_cast", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "ptr_const_cast", since = "1.65.0")]
+    #[rustc_const_stable(feature = "ptr_const_cast", since = "1.65.0")]
     pub const fn cast_const(self) -> *const T {
         self as _
     }
@@ -160,7 +163,7 @@ impl<T: ?Sized> *mut T {
     /// This is similar to `self as usize`, which semantically discards *provenance* and
     /// *address-space* information. However, unlike `self as usize`, casting the returned address
     /// back to a pointer yields [`invalid`][], which is undefined behavior to dereference. To
-    /// properly restore the lost information and obtain a dereferencable pointer, use
+    /// properly restore the lost information and obtain a dereferenceable pointer, use
     /// [`with_addr`][pointer::with_addr] or [`map_addr`][pointer::map_addr].
     ///
     /// If using those APIs is not possible because there is no way to preserve a pointer with the
@@ -581,7 +584,6 @@ impl<T: ?Sized> *mut T {
     ///
     /// For non-`Sized` pointees this operation changes only the data pointer,
     /// leaving the metadata untouched.
-    #[cfg(not(bootstrap))]
     #[unstable(feature = "ptr_mask", issue = "98290")]
     #[must_use = "returns a new pointer rather than modifying its argument"]
     #[inline(always)]
@@ -697,20 +699,16 @@ impl<T: ?Sized> *mut T {
 
     /// Returns whether two pointers are guaranteed to be equal.
     ///
-    /// At runtime this function behaves like `self == other`.
+    /// At runtime this function behaves like `Some(self == other)`.
     /// However, in some contexts (e.g., compile-time evaluation),
     /// it is not always possible to determine equality of two pointers, so this function may
-    /// spuriously return `false` for pointers that later actually turn out to be equal.
-    /// But when it returns `true`, the pointers are guaranteed to be equal.
+    /// spuriously return `None` for pointers that later actually turn out to have its equality known.
+    /// But when it returns `Some`, the pointers' equality is guaranteed to be known.
     ///
-    /// This function is the mirror of [`guaranteed_ne`], but not its inverse. There are pointer
-    /// comparisons for which both functions return `false`.
-    ///
-    /// [`guaranteed_ne`]: #method.guaranteed_ne
-    ///
-    /// The return value may change depending on the compiler version and unsafe code might not
+    /// The return value may change from `Some` to `None` and vice versa depending on the compiler
+    /// version and unsafe code must not
     /// rely on the result of this function for soundness. It is suggested to only use this function
-    /// for performance optimizations where spurious `false` return values by this function do not
+    /// for performance optimizations where spurious `None` return values by this function do not
     /// affect the outcome, but just the performance.
     /// The consequences of using this method to make runtime and compile-time code behave
     /// differently have not been explored. This method should not be used to introduce such
@@ -719,29 +717,25 @@ impl<T: ?Sized> *mut T {
     #[unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[inline]
-    pub const fn guaranteed_eq(self, other: *mut T) -> bool
+    pub const fn guaranteed_eq(self, other: *mut T) -> Option<bool>
     where
         T: Sized,
     {
-        intrinsics::ptr_guaranteed_eq(self as *const _, other as *const _)
+        (self as *const T).guaranteed_eq(other as _)
     }
 
-    /// Returns whether two pointers are guaranteed to be unequal.
+    /// Returns whether two pointers are guaranteed to be inequal.
     ///
-    /// At runtime this function behaves like `self != other`.
+    /// At runtime this function behaves like `Some(self == other)`.
     /// However, in some contexts (e.g., compile-time evaluation),
-    /// it is not always possible to determine the inequality of two pointers, so this function may
-    /// spuriously return `false` for pointers that later actually turn out to be unequal.
-    /// But when it returns `true`, the pointers are guaranteed to be unequal.
+    /// it is not always possible to determine inequality of two pointers, so this function may
+    /// spuriously return `None` for pointers that later actually turn out to have its inequality known.
+    /// But when it returns `Some`, the pointers' inequality is guaranteed to be known.
     ///
-    /// This function is the mirror of [`guaranteed_eq`], but not its inverse. There are pointer
-    /// comparisons for which both functions return `false`.
-    ///
-    /// [`guaranteed_eq`]: #method.guaranteed_eq
-    ///
-    /// The return value may change depending on the compiler version and unsafe code might not
+    /// The return value may change from `Some` to `None` and vice versa depending on the compiler
+    /// version and unsafe code must not
     /// rely on the result of this function for soundness. It is suggested to only use this function
-    /// for performance optimizations where spurious `false` return values by this function do not
+    /// for performance optimizations where spurious `None` return values by this function do not
     /// affect the outcome, but just the performance.
     /// The consequences of using this method to make runtime and compile-time code behave
     /// differently have not been explored. This method should not be used to introduce such
@@ -750,11 +744,11 @@ impl<T: ?Sized> *mut T {
     #[unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     #[inline]
-    pub const unsafe fn guaranteed_ne(self, other: *mut T) -> bool
+    pub const fn guaranteed_ne(self, other: *mut T) -> Option<bool>
     where
         T: Sized,
     {
-        intrinsics::ptr_guaranteed_ne(self as *const _, other as *const _)
+        (self as *const T).guaranteed_ne(other as _)
     }
 
     /// Calculates the distance between two pointers. The returned value is in
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 76eaa191f781..dc90e90402c8 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -2116,6 +2116,7 @@ impl<T, E, F: From<E>> ops::FromResidual<ops::Yeet<E>> for Result<T, F> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<T, E> ops::Residual<T> for Result<convert::Infallible, E> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T, E> const ops::Residual<T> for Result<convert::Infallible, E> {
     type TryType = Result<T, E>;
 }
diff --git a/library/core/src/slice/index.rs b/library/core/src/slice/index.rs
index fd7ecf3daf31..916d0262dedb 100644
--- a/library/core/src/slice/index.rs
+++ b/library/core/src/slice/index.rs
@@ -48,10 +48,12 @@ const fn slice_start_index_len_fail(index: usize, len: usize) -> ! {
 }
 
 // FIXME const-hack
+#[track_caller]
 fn slice_start_index_len_fail_rt(index: usize, len: usize) -> ! {
     panic!("range start index {index} out of range for slice of length {len}");
 }
 
+#[track_caller]
 const fn slice_start_index_len_fail_ct(_: usize, _: usize) -> ! {
     panic!("slice start index is out of range for slice");
 }
@@ -69,10 +71,12 @@ const fn slice_end_index_len_fail(index: usize, len: usize) -> ! {
 }
 
 // FIXME const-hack
+#[track_caller]
 fn slice_end_index_len_fail_rt(index: usize, len: usize) -> ! {
     panic!("range end index {index} out of range for slice of length {len}");
 }
 
+#[track_caller]
 const fn slice_end_index_len_fail_ct(_: usize, _: usize) -> ! {
     panic!("slice end index is out of range for slice");
 }
@@ -88,10 +92,12 @@ const fn slice_index_order_fail(index: usize, end: usize) -> ! {
 }
 
 // FIXME const-hack
+#[track_caller]
 fn slice_index_order_fail_rt(index: usize, end: usize) -> ! {
     panic!("slice index starts at {index} but ends at {end}");
 }
 
+#[track_caller]
 const fn slice_index_order_fail_ct(_: usize, _: usize) -> ! {
     panic!("slice index start is larger than end");
 }
@@ -133,6 +139,8 @@ mod private_slice_index {
     impl Sealed for ops::RangeToInclusive<usize> {}
     #[stable(feature = "slice_index_with_ops_bound_pair", since = "1.53.0")]
     impl Sealed for (ops::Bound<usize>, ops::Bound<usize>) {}
+
+    impl Sealed for ops::IndexRange {}
 }
 
 /// A helper trait used for indexing operations.
@@ -152,6 +160,7 @@ mod private_slice_index {
     message = "the type `{T}` cannot be indexed by `{Self}`",
     label = "slice indices are of type `usize` or ranges of `usize`"
 )]
+#[const_trait]
 pub unsafe trait SliceIndex<T: ?Sized>: private_slice_index::Sealed {
     /// The output type returned by methods.
     #[stable(feature = "slice_get_slice", since = "1.28.0")]
@@ -217,21 +226,23 @@ unsafe impl<T> const SliceIndex<[T]> for usize {
 
     #[inline]
     unsafe fn get_unchecked(self, slice: *const [T]) -> *const T {
+        let this = self;
         // SAFETY: the caller guarantees that `slice` is not dangling, so it
         // cannot be longer than `isize::MAX`. They also guarantee that
         // `self` is in bounds of `slice` so `self` cannot overflow an `isize`,
         // so the call to `add` is safe.
         unsafe {
-            assert_unsafe_precondition!(self < slice.len());
+            assert_unsafe_precondition!([T](this: usize, slice: *const [T]) => this < slice.len());
             slice.as_ptr().add(self)
         }
     }
 
     #[inline]
     unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut T {
+        let this = self;
         // SAFETY: see comments for `get_unchecked` above.
         unsafe {
-            assert_unsafe_precondition!(self < slice.len());
+            assert_unsafe_precondition!([T](this: usize, slice: *mut [T]) => this < slice.len());
             slice.as_mut_ptr().add(self)
         }
     }
@@ -249,6 +260,79 @@ unsafe impl<T> const SliceIndex<[T]> for usize {
     }
 }
 
+/// Because `IndexRange` guarantees `start <= end`, fewer checks are needed here
+/// than there are for a general `Range<usize>` (which might be `100..3`).
+#[rustc_const_unstable(feature = "const_index_range_slice_index", issue = "none")]
+unsafe impl<T> const SliceIndex<[T]> for ops::IndexRange {
+    type Output = [T];
+
+    #[inline]
+    fn get(self, slice: &[T]) -> Option<&[T]> {
+        if self.end() <= slice.len() {
+            // SAFETY: `self` is checked to be valid and in bounds above.
+            unsafe { Some(&*self.get_unchecked(slice)) }
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> {
+        if self.end() <= slice.len() {
+            // SAFETY: `self` is checked to be valid and in bounds above.
+            unsafe { Some(&mut *self.get_unchecked_mut(slice)) }
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T] {
+        let end = self.end();
+        // SAFETY: the caller guarantees that `slice` is not dangling, so it
+        // cannot be longer than `isize::MAX`. They also guarantee that
+        // `self` is in bounds of `slice` so `self` cannot overflow an `isize`,
+        // so the call to `add` is safe.
+
+        unsafe {
+            assert_unsafe_precondition!([T](end: usize, slice: *const [T]) =>
+                end <= slice.len());
+            ptr::slice_from_raw_parts(slice.as_ptr().add(self.start()), self.len())
+        }
+    }
+
+    #[inline]
+    unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T] {
+        let end = self.end();
+        // SAFETY: see comments for `get_unchecked` above.
+        unsafe {
+            assert_unsafe_precondition!([T](end: usize, slice: *mut [T]) =>
+                end <= slice.len());
+            ptr::slice_from_raw_parts_mut(slice.as_mut_ptr().add(self.start()), self.len())
+        }
+    }
+
+    #[inline]
+    fn index(self, slice: &[T]) -> &[T] {
+        if self.end() <= slice.len() {
+            // SAFETY: `self` is checked to be valid and in bounds above.
+            unsafe { &*self.get_unchecked(slice) }
+        } else {
+            slice_end_index_len_fail(self.end(), slice.len())
+        }
+    }
+
+    #[inline]
+    fn index_mut(self, slice: &mut [T]) -> &mut [T] {
+        if self.end() <= slice.len() {
+            // SAFETY: `self` is checked to be valid and in bounds above.
+            unsafe { &mut *self.get_unchecked_mut(slice) }
+        } else {
+            slice_end_index_len_fail(self.end(), slice.len())
+        }
+    }
+}
+
 #[stable(feature = "slice_get_slice_impls", since = "1.15.0")]
 #[rustc_const_unstable(feature = "const_slice_index", issue = "none")]
 unsafe impl<T> const SliceIndex<[T]> for ops::Range<usize> {
@@ -276,22 +360,26 @@ unsafe impl<T> const SliceIndex<[T]> for ops::Range<usize> {
 
     #[inline]
     unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T] {
+        let this = ops::Range { start: self.start, end: self.end };
         // SAFETY: the caller guarantees that `slice` is not dangling, so it
         // cannot be longer than `isize::MAX`. They also guarantee that
         // `self` is in bounds of `slice` so `self` cannot overflow an `isize`,
         // so the call to `add` is safe.
 
         unsafe {
-            assert_unsafe_precondition!(self.end >= self.start && self.end <= slice.len());
+            assert_unsafe_precondition!([T](this: ops::Range<usize>, slice: *const [T]) =>
+            this.end >= this.start && this.end <= slice.len());
             ptr::slice_from_raw_parts(slice.as_ptr().add(self.start), self.end - self.start)
         }
     }
 
     #[inline]
     unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T] {
+        let this = ops::Range { start: self.start, end: self.end };
         // SAFETY: see comments for `get_unchecked` above.
         unsafe {
-            assert_unsafe_precondition!(self.end >= self.start && self.end <= slice.len());
+            assert_unsafe_precondition!([T](this: ops::Range<usize>, slice: *mut [T]) =>
+                this.end >= this.start && this.end <= slice.len());
             ptr::slice_from_raw_parts_mut(slice.as_mut_ptr().add(self.start), self.end - self.start)
         }
     }
diff --git a/library/core/src/slice/iter.rs b/library/core/src/slice/iter.rs
index f43b780ec9a9..ad39ce38319d 100644
--- a/library/core/src/slice/iter.rs
+++ b/library/core/src/slice/iter.rs
@@ -9,7 +9,7 @@ use crate::fmt;
 use crate::intrinsics::{assume, exact_div, unchecked_sub};
 use crate::iter::{FusedIterator, TrustedLen, TrustedRandomAccess, TrustedRandomAccessNoCoerce};
 use crate::marker::{PhantomData, Send, Sized, Sync};
-use crate::mem;
+use crate::mem::{self, SizedTypeProperties};
 use crate::num::NonZeroUsize;
 use crate::ptr::NonNull;
 
@@ -91,11 +91,8 @@ impl<'a, T> Iter<'a, T> {
         unsafe {
             assume(!ptr.is_null());
 
-            let end = if mem::size_of::<T>() == 0 {
-                ptr.wrapping_byte_add(slice.len())
-            } else {
-                ptr.add(slice.len())
-            };
+            let end =
+                if T::IS_ZST { ptr.wrapping_byte_add(slice.len()) } else { ptr.add(slice.len()) };
 
             Self { ptr: NonNull::new_unchecked(ptr as *mut T), end, _marker: PhantomData }
         }
@@ -227,11 +224,8 @@ impl<'a, T> IterMut<'a, T> {
         unsafe {
             assume(!ptr.is_null());
 
-            let end = if mem::size_of::<T>() == 0 {
-                ptr.wrapping_byte_add(slice.len())
-            } else {
-                ptr.add(slice.len())
-            };
+            let end =
+                if T::IS_ZST { ptr.wrapping_byte_add(slice.len()) } else { ptr.add(slice.len()) };
 
             Self { ptr: NonNull::new_unchecked(ptr), end, _marker: PhantomData }
         }
@@ -2754,10 +2748,10 @@ impl<'a, T> Iterator for RChunksMut<'a, T> {
                 None => 0,
             };
             // SAFETY: This type ensures that self.v is a valid pointer with a correct len.
-            // Therefore the bounds check in split_at_mut guarantess the split point is inbounds.
+            // Therefore the bounds check in split_at_mut guarantees the split point is inbounds.
             let (head, tail) = unsafe { self.v.split_at_mut(start) };
             // SAFETY: This type ensures that self.v is a valid pointer with a correct len.
-            // Therefore the bounds check in split_at_mut guarantess the split point is inbounds.
+            // Therefore the bounds check in split_at_mut guarantees the split point is inbounds.
             let (nth, _) = unsafe { tail.split_at_mut(end - start) };
             self.v = head;
             // SAFETY: Nothing else points to or will point to the contents of this slice.
diff --git a/library/core/src/slice/iter/macros.rs b/library/core/src/slice/iter/macros.rs
index 47455760a4bd..ce51d48e3e55 100644
--- a/library/core/src/slice/iter/macros.rs
+++ b/library/core/src/slice/iter/macros.rs
@@ -64,7 +64,7 @@ macro_rules! iterator {
         // backwards by `n`. `n` must not exceed `self.len()`.
         macro_rules! zst_shrink {
             ($self: ident, $n: ident) => {
-                $self.end = $self.end.wrapping_byte_offset(-$n);
+                $self.end = $self.end.wrapping_byte_sub($n);
             }
         }
 
@@ -82,7 +82,7 @@ macro_rules! iterator {
             // returning the old start.
             // Unsafe because the offset must not exceed `self.len()`.
             #[inline(always)]
-            unsafe fn post_inc_start(&mut self, offset: isize) -> * $raw_mut T {
+            unsafe fn post_inc_start(&mut self, offset: usize) -> * $raw_mut T {
                 if mem::size_of::<T>() == 0 {
                     zst_shrink!(self, offset);
                     self.ptr.as_ptr()
@@ -90,7 +90,7 @@ macro_rules! iterator {
                     let old = self.ptr.as_ptr();
                     // SAFETY: the caller guarantees that `offset` doesn't exceed `self.len()`,
                     // so this new pointer is inside `self` and thus guaranteed to be non-null.
-                    self.ptr = unsafe { NonNull::new_unchecked(self.ptr.as_ptr().offset(offset)) };
+                    self.ptr = unsafe { NonNull::new_unchecked(self.ptr.as_ptr().add(offset)) };
                     old
                 }
             }
@@ -99,15 +99,15 @@ macro_rules! iterator {
             // returning the new end.
             // Unsafe because the offset must not exceed `self.len()`.
             #[inline(always)]
-            unsafe fn pre_dec_end(&mut self, offset: isize) -> * $raw_mut T {
-                if mem::size_of::<T>() == 0 {
+            unsafe fn pre_dec_end(&mut self, offset: usize) -> * $raw_mut T {
+                if T::IS_ZST {
                     zst_shrink!(self, offset);
                     self.ptr.as_ptr()
                 } else {
                     // SAFETY: the caller guarantees that `offset` doesn't exceed `self.len()`,
                     // which is guaranteed to not overflow an `isize`. Also, the resulting pointer
                     // is in bounds of `slice`, which fulfills the other requirements for `offset`.
-                    self.end = unsafe { self.end.offset(-offset) };
+                    self.end = unsafe { self.end.sub(offset) };
                     self.end
                 }
             }
@@ -140,7 +140,7 @@ macro_rules! iterator {
                 // since we check if the iterator is empty first.
                 unsafe {
                     assume(!self.ptr.as_ptr().is_null());
-                    if mem::size_of::<T>() != 0 {
+                    if !<T>::IS_ZST {
                         assume(!self.end.is_null());
                     }
                     if is_empty!(self) {
@@ -166,7 +166,7 @@ macro_rules! iterator {
             fn nth(&mut self, n: usize) -> Option<$elem> {
                 if n >= len!(self) {
                     // This iterator is now empty.
-                    if mem::size_of::<T>() == 0 {
+                    if T::IS_ZST {
                         // We have to do it this way as `ptr` may never be 0, but `end`
                         // could be (due to wrapping).
                         self.end = self.ptr.as_ptr();
@@ -180,7 +180,7 @@ macro_rules! iterator {
                 }
                 // SAFETY: We are in bounds. `post_inc_start` does the right thing even for ZSTs.
                 unsafe {
-                    self.post_inc_start(n as isize);
+                    self.post_inc_start(n);
                     Some(next_unchecked!(self))
                 }
             }
@@ -189,7 +189,7 @@ macro_rules! iterator {
             fn advance_by(&mut self, n: usize) -> Result<(), usize> {
                 let advance = cmp::min(len!(self), n);
                 // SAFETY: By construction, `advance` does not exceed `self.len()`.
-                unsafe { self.post_inc_start(advance as isize) };
+                unsafe { self.post_inc_start(advance) };
                 if advance == n { Ok(()) } else { Err(advance) }
             }
 
@@ -355,7 +355,7 @@ macro_rules! iterator {
                 // empty first.
                 unsafe {
                     assume(!self.ptr.as_ptr().is_null());
-                    if mem::size_of::<T>() != 0 {
+                    if !<T>::IS_ZST {
                         assume(!self.end.is_null());
                     }
                     if is_empty!(self) {
@@ -375,7 +375,7 @@ macro_rules! iterator {
                 }
                 // SAFETY: We are in bounds. `pre_dec_end` does the right thing even for ZSTs.
                 unsafe {
-                    self.pre_dec_end(n as isize);
+                    self.pre_dec_end(n);
                     Some(next_back_unchecked!(self))
                 }
             }
@@ -384,7 +384,7 @@ macro_rules! iterator {
             fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
                 let advance = cmp::min(len!(self), n);
                 // SAFETY: By construction, `advance` does not exceed `self.len()`.
-                unsafe { self.pre_dec_end(advance as isize) };
+                unsafe { self.pre_dec_end(advance) };
                 if advance == n { Ok(()) } else { Err(advance) }
             }
         }
diff --git a/library/core/src/slice/memchr.rs b/library/core/src/slice/memchr.rs
index dffeaf6a834e..c848c2e18e9b 100644
--- a/library/core/src/slice/memchr.rs
+++ b/library/core/src/slice/memchr.rs
@@ -16,35 +16,51 @@ const USIZE_BYTES: usize = mem::size_of::<usize>();
 /// bytes where the borrow propagated all the way to the most significant
 /// bit."
 #[inline]
-fn contains_zero_byte(x: usize) -> bool {
+const fn contains_zero_byte(x: usize) -> bool {
     x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
 }
 
 #[cfg(target_pointer_width = "16")]
 #[inline]
-fn repeat_byte(b: u8) -> usize {
+const fn repeat_byte(b: u8) -> usize {
     (b as usize) << 8 | b as usize
 }
 
 #[cfg(not(target_pointer_width = "16"))]
 #[inline]
-fn repeat_byte(b: u8) -> usize {
+const fn repeat_byte(b: u8) -> usize {
     (b as usize) * (usize::MAX / 255)
 }
 
 /// Returns the first index matching the byte `x` in `text`.
 #[must_use]
 #[inline]
-pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
-    // Fast path for small slices
+pub const fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+    // Fast path for small slices.
     if text.len() < 2 * USIZE_BYTES {
-        return text.iter().position(|elt| *elt == x);
+        return memchr_naive(x, text);
     }
 
-    memchr_general_case(x, text)
+    memchr_aligned(x, text)
 }
 
-fn memchr_general_case(x: u8, text: &[u8]) -> Option<usize> {
+#[inline]
+const fn memchr_naive(x: u8, text: &[u8]) -> Option<usize> {
+    let mut i = 0;
+
+    // FIXME(const-hack): Replace with `text.iter().pos(|c| *c == x)`.
+    while i < text.len() {
+        if text[i] == x {
+            return Some(i);
+        }
+
+        i += 1;
+    }
+
+    None
+}
+
+const fn memchr_aligned(x: u8, text: &[u8]) -> Option<usize> {
     // Scan for a single byte value by reading two `usize` words at a time.
     //
     // Split `text` in three parts
@@ -59,7 +75,7 @@ fn memchr_general_case(x: u8, text: &[u8]) -> Option<usize> {
 
     if offset > 0 {
         offset = cmp::min(offset, len);
-        if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+        if let Some(index) = memchr_naive(x, &text[..offset]) {
             return Some(index);
         }
     }
@@ -84,7 +100,8 @@ fn memchr_general_case(x: u8, text: &[u8]) -> Option<usize> {
     }
 
     // Find the byte after the point the body loop stopped.
-    text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    // FIXME(const-hack): Use `?` instead.
+    if let Some(i) = memchr_naive(x, &text[offset..]) { Some(offset + i) } else { None }
 }
 
 /// Returns the last index matching the byte `x` in `text`.
@@ -124,8 +141,8 @@ pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
         // SAFETY: offset starts at len - suffix.len(), as long as it is greater than
         // min_aligned_offset (prefix.len()) the remaining distance is at least 2 * chunk_bytes.
         unsafe {
-            let u = *(ptr.offset(offset as isize - 2 * chunk_bytes as isize) as *const Chunk);
-            let v = *(ptr.offset(offset as isize - chunk_bytes as isize) as *const Chunk);
+            let u = *(ptr.add(offset - 2 * chunk_bytes) as *const Chunk);
+            let v = *(ptr.add(offset - chunk_bytes) as *const Chunk);
 
             // Break if there is a matching byte.
             let zu = contains_zero_byte(u ^ repeated_x);
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index d5706c388f00..cd04fa004424 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -9,7 +9,7 @@
 use crate::cmp::Ordering::{self, Greater, Less};
 use crate::intrinsics::{assert_unsafe_precondition, exact_div};
 use crate::marker::Copy;
-use crate::mem;
+use crate::mem::{self, SizedTypeProperties};
 use crate::num::NonZeroUsize;
 use crate::ops::{Bound, FnMut, OneSidedRange, Range, RangeBounds};
 use crate::option::Option;
@@ -656,10 +656,11 @@ impl<T> [T] {
     #[unstable(feature = "slice_swap_unchecked", issue = "88539")]
     #[rustc_const_unstable(feature = "const_swap", issue = "83163")]
     pub const unsafe fn swap_unchecked(&mut self, a: usize, b: usize) {
-        let ptr = self.as_mut_ptr();
+        let this = self;
+        let ptr = this.as_mut_ptr();
         // SAFETY: caller has to guarantee that `a < self.len()` and `b < self.len()`
         unsafe {
-            assert_unsafe_precondition!(a < self.len() && b < self.len());
+            assert_unsafe_precondition!([T](a: usize, b: usize, this: &mut [T]) => a < this.len() && b < this.len());
             ptr::swap(ptr.add(a), ptr.add(b));
         }
     }
@@ -972,9 +973,10 @@ impl<T> [T] {
     #[inline]
     #[must_use]
     pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]] {
+        let this = self;
         // SAFETY: Caller must guarantee that `N` is nonzero and exactly divides the slice length
         let new_len = unsafe {
-            assert_unsafe_precondition!(N != 0 && self.len() % N == 0);
+            assert_unsafe_precondition!([T](this: &[T], N: usize) => N != 0 && this.len() % N == 0);
             exact_div(self.len(), N)
         };
         // SAFETY: We cast a slice of `new_len * N` elements into
@@ -1111,10 +1113,11 @@ impl<T> [T] {
     #[inline]
     #[must_use]
     pub unsafe fn as_chunks_unchecked_mut<const N: usize>(&mut self) -> &mut [[T; N]] {
+        let this = &*self;
         // SAFETY: Caller must guarantee that `N` is nonzero and exactly divides the slice length
         let new_len = unsafe {
-            assert_unsafe_precondition!(N != 0 && self.len() % N == 0);
-            exact_div(self.len(), N)
+            assert_unsafe_precondition!([T](this: &[T], N: usize) => N != 0 && this.len() % N == 0);
+            exact_div(this.len(), N)
         };
         // SAFETY: We cast a slice of `new_len * N` elements into
         // a slice of `new_len` many `N` elements chunks.
@@ -1577,7 +1580,8 @@ impl<T> [T] {
     #[inline]
     #[track_caller]
     #[must_use]
-    pub fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T]) {
+    #[rustc_const_unstable(feature = "const_slice_split_at_mut", issue = "101804")]
+    pub const fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T]) {
         assert!(mid <= self.len());
         // SAFETY: `[ptr; mid]` and `[mid; len]` are inside `self`, which
         // fulfills the requirements of `from_raw_parts_mut`.
@@ -1676,9 +1680,10 @@ impl<T> [T] {
     /// assert_eq!(v, [1, 2, 3, 4, 5, 6]);
     /// ```
     #[unstable(feature = "slice_split_at_unchecked", reason = "new API", issue = "76014")]
+    #[rustc_const_unstable(feature = "const_slice_split_at_mut", issue = "101804")]
     #[inline]
     #[must_use]
-    pub unsafe fn split_at_mut_unchecked(&mut self, mid: usize) -> (&mut [T], &mut [T]) {
+    pub const unsafe fn split_at_mut_unchecked(&mut self, mid: usize) -> (&mut [T], &mut [T]) {
         let len = self.len();
         let ptr = self.as_mut_ptr();
 
@@ -1687,7 +1692,7 @@ impl<T> [T] {
         // `[ptr; mid]` and `[mid; len]` are not overlapping, so returning a mutable reference
         // is fine.
         unsafe {
-            assert_unsafe_precondition!(mid <= len);
+            assert_unsafe_precondition!((mid: usize, len: usize) => mid <= len);
             (from_raw_parts_mut(ptr, mid), from_raw_parts_mut(ptr.add(mid), len - mid))
         }
     }
@@ -2321,7 +2326,7 @@ impl<T> [T] {
     }
 
     /// Binary searches this slice for a given element.
-    /// This behaves similary to [`contains`] if this slice is sorted.
+    /// This behaves similarly to [`contains`] if this slice is sorted.
     ///
     /// If the value is found then [`Result::Ok`] is returned, containing the
     /// index of the matching element. If there are multiple matches, then any
@@ -2537,7 +2542,7 @@ impl<T> [T] {
     where
         T: Ord,
     {
-        sort::quicksort(self, |a, b| a.lt(b));
+        sort::quicksort(self, T::lt);
     }
 
     /// Sorts the slice with a comparator function, but might not preserve the order of equal
@@ -2640,9 +2645,10 @@ impl<T> [T] {
     /// less than or equal to any value at a position `j > index`. Additionally, this reordering is
     /// unstable (i.e. any number of equal elements may end up at position `index`), in-place
     /// (i.e. does not allocate), and *O*(*n*) worst-case. This function is also/ known as "kth
-    /// element" in other libraries. It returns a triplet of the following values: all elements less
-    /// than the one at the given index, the value at the given index, and all elements greater than
-    /// the one at the given index.
+    /// element" in other libraries. It returns a triplet of the following from the reordered slice:
+    /// the subslice prior to `index`, the element at `index`, and the subslice after `index`;
+    /// accordingly, the values in those two subslices will respectively all be less-than-or-equal-to
+    /// and greater-than-or-equal-to the value of the element at `index`.
     ///
     /// # Current implementation
     ///
@@ -2676,8 +2682,7 @@ impl<T> [T] {
     where
         T: Ord,
     {
-        let mut f = |a: &T, b: &T| a.lt(b);
-        sort::partition_at_index(self, index, &mut f)
+        sort::partition_at_index(self, index, T::lt)
     }
 
     /// Reorder the slice with a comparator function such that the element at `index` is at its
@@ -2687,10 +2692,11 @@ impl<T> [T] {
     /// less than or equal to any value at a position `j > index` using the comparator function.
     /// Additionally, this reordering is unstable (i.e. any number of equal elements may end up at
     /// position `index`), in-place (i.e. does not allocate), and *O*(*n*) worst-case. This function
-    /// is also known as "kth element" in other libraries. It returns a triplet of the following
-    /// values: all elements less than the one at the given index, the value at the given index,
-    /// and all elements greater than the one at the given index, using the provided comparator
-    /// function.
+    /// is also known as "kth element" in other libraries. It returns a triplet of the following from
+    /// the slice reordered according to the provided comparator function: the subslice prior to
+    /// `index`, the element at `index`, and the subslice after `index`; accordingly, the values in
+    /// those two subslices will respectively all be less-than-or-equal-to and greater-than-or-equal-to
+    /// the value of the element at `index`.
     ///
     /// # Current implementation
     ///
@@ -2728,8 +2734,7 @@ impl<T> [T] {
     where
         F: FnMut(&T, &T) -> Ordering,
     {
-        let mut f = |a: &T, b: &T| compare(a, b) == Less;
-        sort::partition_at_index(self, index, &mut f)
+        sort::partition_at_index(self, index, |a: &T, b: &T| compare(a, b) == Less)
     }
 
     /// Reorder the slice with a key extraction function such that the element at `index` is at its
@@ -2739,10 +2744,11 @@ impl<T> [T] {
     /// less than or equal to any value at a position `j > index` using the key extraction function.
     /// Additionally, this reordering is unstable (i.e. any number of equal elements may end up at
     /// position `index`), in-place (i.e. does not allocate), and *O*(*n*) worst-case. This function
-    /// is also known as "kth element" in other libraries. It returns a triplet of the following
-    /// values: all elements less than the one at the given index, the value at the given index, and
-    /// all elements greater than the one at the given index, using the provided key extraction
-    /// function.
+    /// is also known as "kth element" in other libraries. It returns a triplet of the following from
+    /// the slice reordered according to the provided key extraction function: the subslice prior to
+    /// `index`, the element at `index`, and the subslice after `index`; accordingly, the values in
+    /// those two subslices will respectively all be less-than-or-equal-to and greater-than-or-equal-to
+    /// the value of the element at `index`.
     ///
     /// # Current implementation
     ///
@@ -2781,8 +2787,7 @@ impl<T> [T] {
         F: FnMut(&T) -> K,
         K: Ord,
     {
-        let mut g = |a: &T, b: &T| f(a).lt(&f(b));
-        sort::partition_at_index(self, index, &mut g)
+        sort::partition_at_index(self, index, |a: &T, b: &T| f(a).lt(&f(b)))
     }
 
     /// Moves all consecutive repeated elements to the end of the slice according to the
@@ -3456,7 +3461,7 @@ impl<T> [T] {
     #[must_use]
     pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T]) {
         // Note that most of this function will be constant-evaluated,
-        if mem::size_of::<U>() == 0 || mem::size_of::<T>() == 0 {
+        if U::IS_ZST || T::IS_ZST {
             // handle ZSTs specially, which is – don't handle them at all.
             return (self, &[], &[]);
         }
@@ -3517,7 +3522,7 @@ impl<T> [T] {
     #[must_use]
     pub unsafe fn align_to_mut<U>(&mut self) -> (&mut [T], &mut [U], &mut [T]) {
         // Note that most of this function will be constant-evaluated,
-        if mem::size_of::<U>() == 0 || mem::size_of::<T>() == 0 {
+        if U::IS_ZST || T::IS_ZST {
             // handle ZSTs specially, which is – don't handle them at all.
             return (self, &mut [], &mut []);
         }
@@ -3530,7 +3535,7 @@ impl<T> [T] {
         // alignment targeted for U.
         // `crate::ptr::align_offset` is called with a correctly aligned and
         // valid pointer `ptr` (it comes from a reference to `self`) and with
-        // a size that is a power of two (since it comes from the alignement for U),
+        // a size that is a power of two (since it comes from the alignment for U),
         // satisfying its safety constraints.
         let offset = unsafe { crate::ptr::align_offset(ptr, mem::align_of::<U>()) };
         if offset > self.len() {
@@ -4063,7 +4068,7 @@ impl<T, const N: usize> [[T; N]] {
     /// ```
     #[unstable(feature = "slice_flatten", issue = "95629")]
     pub fn flatten(&self) -> &[T] {
-        let len = if crate::mem::size_of::<T>() == 0 {
+        let len = if T::IS_ZST {
             self.len().checked_mul(N).expect("slice len overflow")
         } else {
             // SAFETY: `self.len() * N` cannot overflow because `self` is
@@ -4101,7 +4106,7 @@ impl<T, const N: usize> [[T; N]] {
     /// ```
     #[unstable(feature = "slice_flatten", issue = "95629")]
     pub fn flatten_mut(&mut self) -> &mut [T] {
-        let len = if crate::mem::size_of::<T>() == 0 {
+        let len = if T::IS_ZST {
             self.len().checked_mul(N).expect("slice len overflow")
         } else {
             // SAFETY: `self.len() * N` cannot overflow because `self` is
diff --git a/library/core/src/slice/raw.rs b/library/core/src/slice/raw.rs
index 107e71ab68b0..f1e8bc79bf4a 100644
--- a/library/core/src/slice/raw.rs
+++ b/library/core/src/slice/raw.rs
@@ -90,7 +90,7 @@ use crate::ptr;
 pub const unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T] {
     // SAFETY: the caller must uphold the safety contract for `from_raw_parts`.
     unsafe {
-        assert_unsafe_precondition!(
+        assert_unsafe_precondition!([T](data: *const T, len: usize) =>
             is_aligned_and_not_null(data)
                 && crate::mem::size_of::<T>().saturating_mul(len) <= isize::MAX as usize
         );
@@ -134,7 +134,7 @@ pub const unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T]
 pub const unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a mut [T] {
     // SAFETY: the caller must uphold the safety contract for `from_raw_parts_mut`.
     unsafe {
-        assert_unsafe_precondition!(
+        assert_unsafe_precondition!([T](data: *mut T, len: usize) =>
             is_aligned_and_not_null(data)
                 && crate::mem::size_of::<T>().saturating_mul(len) <= isize::MAX as usize
         );
diff --git a/library/core/src/slice/rotate.rs b/library/core/src/slice/rotate.rs
index 4589c6c0f04a..fa8c238f8e7a 100644
--- a/library/core/src/slice/rotate.rs
+++ b/library/core/src/slice/rotate.rs
@@ -1,5 +1,5 @@
 use crate::cmp;
-use crate::mem::{self, MaybeUninit};
+use crate::mem::{self, MaybeUninit, SizedTypeProperties};
 use crate::ptr;
 
 /// Rotates the range `[mid-left, mid+right)` such that the element at `mid` becomes the first
@@ -63,7 +63,7 @@ use crate::ptr;
 /// when `left < right` the swapping happens from the left instead.
 pub unsafe fn ptr_rotate<T>(mut left: usize, mut mid: *mut T, mut right: usize) {
     type BufType = [usize; 32];
-    if mem::size_of::<T>() == 0 {
+    if T::IS_ZST {
         return;
     }
     loop {
diff --git a/library/core/src/slice/sort.rs b/library/core/src/slice/sort.rs
index 8b025da2a46e..87f77b7f21d6 100644
--- a/library/core/src/slice/sort.rs
+++ b/library/core/src/slice/sort.rs
@@ -7,7 +7,7 @@
 //! stable sorting implementation.
 
 use crate::cmp;
-use crate::mem::{self, MaybeUninit};
+use crate::mem::{self, MaybeUninit, SizedTypeProperties};
 use crate::ptr;
 
 /// When dropped, copies from `src` into `dest`.
@@ -365,12 +365,12 @@ where
         if count > 0 {
             macro_rules! left {
                 () => {
-                    l.add(*start_l as usize)
+                    l.add(usize::from(*start_l))
                 };
             }
             macro_rules! right {
                 () => {
-                    r.sub((*start_r as usize) + 1)
+                    r.sub(usize::from(*start_r) + 1)
                 };
             }
 
@@ -458,7 +458,7 @@ where
             //    the last block, so the `l.offset` calls are valid.
             unsafe {
                 end_l = end_l.sub(1);
-                ptr::swap(l.add(*end_l as usize), r.sub(1));
+                ptr::swap(l.add(usize::from(*end_l)), r.sub(1));
                 r = r.sub(1);
             }
         }
@@ -471,7 +471,7 @@ where
             // SAFETY: See the reasoning in [remaining-elements-safety].
             unsafe {
                 end_r = end_r.sub(1);
-                ptr::swap(l, r.sub((*end_r as usize) + 1));
+                ptr::swap(l, r.sub(usize::from(*end_r) + 1));
                 l = l.add(1);
             }
         }
@@ -813,7 +813,7 @@ where
     F: FnMut(&T, &T) -> bool,
 {
     // Sorting has no meaningful behavior on zero-sized types.
-    if mem::size_of::<T>() == 0 {
+    if T::IS_ZST {
         return;
     }
 
@@ -898,7 +898,7 @@ where
         panic!("partition_at_index index {} greater than length of slice {}", index, v.len());
     }
 
-    if mem::size_of::<T>() == 0 {
+    if T::IS_ZST {
         // Sorting has no meaningful behavior on zero-sized types. Do nothing.
     } else if index == v.len() - 1 {
         // Find max element and place it in the last position of the array. We're free to use
diff --git a/library/core/src/str/error.rs b/library/core/src/str/error.rs
index 343889b6999f..a11b5add42eb 100644
--- a/library/core/src/str/error.rs
+++ b/library/core/src/str/error.rs
@@ -1,6 +1,5 @@
 //! Defines utf8 error type.
 
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt;
 
@@ -124,7 +123,6 @@ impl fmt::Display for Utf8Error {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Error for Utf8Error {
     #[allow(deprecated)]
@@ -148,7 +146,6 @@ impl fmt::Display for ParseBoolError {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Error for ParseBoolError {
     #[allow(deprecated)]
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index 2120bf61d759..fbc0fc397a5d 100644
--- a/library/core/src/str/mod.rs
+++ b/library/core/src/str/mod.rs
@@ -91,10 +91,12 @@ const fn slice_error_fail(s: &str, begin: usize, end: usize) -> ! {
     }
 }
 
+#[track_caller]
 const fn slice_error_fail_ct(_: &str, _: usize, _: usize) -> ! {
     panic!("failed to slice string");
 }
 
+#[track_caller]
 fn slice_error_fail_rt(s: &str, begin: usize, end: usize) -> ! {
     const MAX_DISPLAY_LENGTH: usize = 256;
     let trunc_len = s.floor_char_boundary(MAX_DISPLAY_LENGTH);
@@ -2640,5 +2642,4 @@ impl_fn_for_zst! {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[cfg(not(bootstrap))]
 impl !crate::error::Error for &str {}
diff --git a/library/core/src/str/traits.rs b/library/core/src/str/traits.rs
index e9649fc91fa0..18f2ce6edc72 100644
--- a/library/core/src/str/traits.rs
+++ b/library/core/src/str/traits.rs
@@ -573,8 +573,8 @@ impl FromStr for bool {
 
     /// Parse a `bool` from a string.
     ///
-    /// Yields a `Result<bool, ParseBoolError>`, because `s` may or may not
-    /// actually be parseable.
+    /// The only accepted values are `"true"` and `"false"`. Any other input
+    /// will return an error.
     ///
     /// # Examples
     ///
diff --git a/library/core/src/sync/exclusive.rs b/library/core/src/sync/exclusive.rs
index a7519ab5ab63..c65c275000ce 100644
--- a/library/core/src/sync/exclusive.rs
+++ b/library/core/src/sync/exclusive.rs
@@ -100,6 +100,7 @@ impl<T: Sized> Exclusive<T> {
     /// Wrap a value in an `Exclusive`
     #[unstable(feature = "exclusive_wrapper", issue = "98407")]
     #[must_use]
+    #[inline]
     pub const fn new(t: T) -> Self {
         Self { inner: t }
     }
@@ -107,6 +108,7 @@ impl<T: Sized> Exclusive<T> {
     /// Unwrap the value contained in the `Exclusive`
     #[unstable(feature = "exclusive_wrapper", issue = "98407")]
     #[must_use]
+    #[inline]
     pub const fn into_inner(self) -> T {
         self.inner
     }
@@ -116,6 +118,7 @@ impl<T: ?Sized> Exclusive<T> {
     /// Get exclusive access to the underlying value.
     #[unstable(feature = "exclusive_wrapper", issue = "98407")]
     #[must_use]
+    #[inline]
     pub const fn get_mut(&mut self) -> &mut T {
         &mut self.inner
     }
@@ -128,6 +131,7 @@ impl<T: ?Sized> Exclusive<T> {
     /// produce _pinned_ access to the underlying value.
     #[unstable(feature = "exclusive_wrapper", issue = "98407")]
     #[must_use]
+    #[inline]
     pub const fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
         // SAFETY: `Exclusive` can only produce `&mut T` if itself is unpinned
         // `Pin::map_unchecked_mut` is not const, so we do this conversion manually
@@ -139,6 +143,7 @@ impl<T: ?Sized> Exclusive<T> {
     /// building an `Exclusive` with [`Exclusive::new`].
     #[unstable(feature = "exclusive_wrapper", issue = "98407")]
     #[must_use]
+    #[inline]
     pub const fn from_mut(r: &'_ mut T) -> &'_ mut Exclusive<T> {
         // SAFETY: repr is ≥ C, so refs have the same layout; and `Exclusive` properties are `&mut`-agnostic
         unsafe { &mut *(r as *mut T as *mut Exclusive<T>) }
@@ -149,6 +154,7 @@ impl<T: ?Sized> Exclusive<T> {
     /// building an `Exclusive` with [`Exclusive::new`].
     #[unstable(feature = "exclusive_wrapper", issue = "98407")]
     #[must_use]
+    #[inline]
     pub const fn from_pin_mut(r: Pin<&'_ mut T>) -> Pin<&'_ mut Exclusive<T>> {
         // SAFETY: `Exclusive` can only produce `&mut T` if itself is unpinned
         // `Pin::map_unchecked_mut` is not const, so we do this conversion manually
@@ -158,6 +164,7 @@ impl<T: ?Sized> Exclusive<T> {
 
 #[unstable(feature = "exclusive_wrapper", issue = "98407")]
 impl<T> From<T> for Exclusive<T> {
+    #[inline]
     fn from(t: T) -> Self {
         Self::new(t)
     }
@@ -166,7 +173,7 @@ impl<T> From<T> for Exclusive<T> {
 #[unstable(feature = "exclusive_wrapper", issue = "98407")]
 impl<T: Future + ?Sized> Future for Exclusive<T> {
     type Output = T::Output;
-
+    #[inline]
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         self.get_pin_mut().poll(cx)
     }
diff --git a/library/core/src/task/wake.rs b/library/core/src/task/wake.rs
index 60ecc9c0bdb1..0cff972df3a5 100644
--- a/library/core/src/task/wake.rs
+++ b/library/core/src/task/wake.rs
@@ -186,17 +186,19 @@ pub struct Context<'a> {
 impl<'a> Context<'a> {
     /// Create a new `Context` from a [`&Waker`](Waker).
     #[stable(feature = "futures_api", since = "1.36.0")]
+    #[rustc_const_unstable(feature = "const_waker", issue = "102012")]
     #[must_use]
     #[inline]
-    pub fn from_waker(waker: &'a Waker) -> Self {
+    pub const fn from_waker(waker: &'a Waker) -> Self {
         Context { waker, _marker: PhantomData }
     }
 
     /// Returns a reference to the [`Waker`] for the current task.
     #[stable(feature = "futures_api", since = "1.36.0")]
+    #[rustc_const_unstable(feature = "const_waker", issue = "102012")]
     #[must_use]
     #[inline]
-    pub fn waker(&self) -> &'a Waker {
+    pub const fn waker(&self) -> &'a Waker {
         &self.waker
     }
 }
@@ -311,7 +313,8 @@ impl Waker {
     #[inline]
     #[must_use]
     #[stable(feature = "futures_api", since = "1.36.0")]
-    pub unsafe fn from_raw(waker: RawWaker) -> Waker {
+    #[rustc_const_unstable(feature = "const_waker", issue = "102012")]
+    pub const unsafe fn from_raw(waker: RawWaker) -> Waker {
         Waker { waker }
     }
 
diff --git a/library/core/src/time.rs b/library/core/src/time.rs
index 153dc4dbb083..4f29ecc0fba8 100644
--- a/library/core/src/time.rs
+++ b/library/core/src/time.rs
@@ -1280,7 +1280,7 @@ macro_rules! try_from_secs {
             let rem_msb = nanos_tmp & rem_msb_mask == 0;
             let add_ns = !(rem_msb || (is_even && is_tie));
 
-            // f32 does not have enough presicion to trigger the second branch
+            // f32 does not have enough precision to trigger the second branch
             // since it can not represent numbers between 0.999_999_940_395 and 1.0.
             let nanos = nanos + add_ns as u32;
             if ($mant_bits == 23) || (nanos != NANOS_PER_SEC) { (0, nanos) } else { (1, 0) }
@@ -1299,9 +1299,9 @@ macro_rules! try_from_secs {
             let rem_msb = nanos_tmp & rem_msb_mask == 0;
             let add_ns = !(rem_msb || (is_even && is_tie));
 
-            // f32 does not have enough presicion to trigger the second branch.
+            // f32 does not have enough precision to trigger the second branch.
             // For example, it can not represent numbers between 1.999_999_880...
-            // and 2.0. Bigger values result in even smaller presicion of the
+            // and 2.0. Bigger values result in even smaller precision of the
             // fractional part.
             let nanos = nanos + add_ns as u32;
             if ($mant_bits == 23) || (nanos != NANOS_PER_SEC) {
diff --git a/library/core/src/tuple.rs b/library/core/src/tuple.rs
index aa8a2425bf41..fc91fe468cc2 100644
--- a/library/core/src/tuple.rs
+++ b/library/core/src/tuple.rs
@@ -93,7 +93,8 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($T:Default),+> Default for ($($T,)+) {
+            #[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+            impl<$($T: ~const Default),+> const Default for ($($T,)+) {
                 #[inline]
                 fn default() -> ($($T,)+) {
                     ($({ let x: $T = Default::default(); x},)+)
diff --git a/library/core/src/unicode/printable.rs b/library/core/src/unicode/printable.rs
index 31cf88a41497..ffb18a5ba8b3 100644
--- a/library/core/src/unicode/printable.rs
+++ b/library/core/src/unicode/printable.rs
@@ -54,7 +54,7 @@ pub(crate) fn is_printable(x: char) -> bool {
         if 0x2a6e0 <= x && x < 0x2a700 {
             return false;
         }
-        if 0x2b739 <= x && x < 0x2b740 {
+        if 0x2b73a <= x && x < 0x2b740 {
             return false;
         }
         if 0x2b81e <= x && x < 0x2b820 {
@@ -69,7 +69,10 @@ pub(crate) fn is_printable(x: char) -> bool {
         if 0x2fa1e <= x && x < 0x30000 {
             return false;
         }
-        if 0x3134b <= x && x < 0xe0100 {
+        if 0x3134b <= x && x < 0x31350 {
+            return false;
+        }
+        if 0x323b0 <= x && x < 0xe0100 {
             return false;
         }
         if 0xe01f0 <= x && x < 0x110000 {
@@ -92,7 +95,7 @@ const SINGLETONS0U: &[(u8, u8)] = &[
     (0x0b, 25),
     (0x0c, 26),
     (0x0d, 16),
-    (0x0e, 13),
+    (0x0e, 12),
     (0x0f, 4),
     (0x10, 3),
     (0x12, 18),
@@ -142,24 +145,24 @@ const SINGLETONS0L: &[u8] = &[
     0xe4, 0xe5, 0xf0, 0x0d, 0x11, 0x45, 0x49, 0x64,
     0x65, 0x80, 0x84, 0xb2, 0xbc, 0xbe, 0xbf, 0xd5,
     0xd7, 0xf0, 0xf1, 0x83, 0x85, 0x8b, 0xa4, 0xa6,
-    0xbe, 0xbf, 0xc5, 0xc7, 0xce, 0xcf, 0xda, 0xdb,
-    0x48, 0x98, 0xbd, 0xcd, 0xc6, 0xce, 0xcf, 0x49,
-    0x4e, 0x4f, 0x57, 0x59, 0x5e, 0x5f, 0x89, 0x8e,
-    0x8f, 0xb1, 0xb6, 0xb7, 0xbf, 0xc1, 0xc6, 0xc7,
-    0xd7, 0x11, 0x16, 0x17, 0x5b, 0x5c, 0xf6, 0xf7,
-    0xfe, 0xff, 0x80, 0x6d, 0x71, 0xde, 0xdf, 0x0e,
-    0x1f, 0x6e, 0x6f, 0x1c, 0x1d, 0x5f, 0x7d, 0x7e,
-    0xae, 0xaf, 0x7f, 0xbb, 0xbc, 0x16, 0x17, 0x1e,
-    0x1f, 0x46, 0x47, 0x4e, 0x4f, 0x58, 0x5a, 0x5c,
-    0x5e, 0x7e, 0x7f, 0xb5, 0xc5, 0xd4, 0xd5, 0xdc,
-    0xf0, 0xf1, 0xf5, 0x72, 0x73, 0x8f, 0x74, 0x75,
-    0x96, 0x26, 0x2e, 0x2f, 0xa7, 0xaf, 0xb7, 0xbf,
-    0xc7, 0xcf, 0xd7, 0xdf, 0x9a, 0x40, 0x97, 0x98,
-    0x30, 0x8f, 0x1f, 0xd2, 0xd4, 0xce, 0xff, 0x4e,
-    0x4f, 0x5a, 0x5b, 0x07, 0x08, 0x0f, 0x10, 0x27,
-    0x2f, 0xee, 0xef, 0x6e, 0x6f, 0x37, 0x3d, 0x3f,
-    0x42, 0x45, 0x90, 0x91, 0x53, 0x67, 0x75, 0xc8,
-    0xc9, 0xd0, 0xd1, 0xd8, 0xd9, 0xe7, 0xfe, 0xff,
+    0xbe, 0xbf, 0xc5, 0xc7, 0xcf, 0xda, 0xdb, 0x48,
+    0x98, 0xbd, 0xcd, 0xc6, 0xce, 0xcf, 0x49, 0x4e,
+    0x4f, 0x57, 0x59, 0x5e, 0x5f, 0x89, 0x8e, 0x8f,
+    0xb1, 0xb6, 0xb7, 0xbf, 0xc1, 0xc6, 0xc7, 0xd7,
+    0x11, 0x16, 0x17, 0x5b, 0x5c, 0xf6, 0xf7, 0xfe,
+    0xff, 0x80, 0x6d, 0x71, 0xde, 0xdf, 0x0e, 0x1f,
+    0x6e, 0x6f, 0x1c, 0x1d, 0x5f, 0x7d, 0x7e, 0xae,
+    0xaf, 0x7f, 0xbb, 0xbc, 0x16, 0x17, 0x1e, 0x1f,
+    0x46, 0x47, 0x4e, 0x4f, 0x58, 0x5a, 0x5c, 0x5e,
+    0x7e, 0x7f, 0xb5, 0xc5, 0xd4, 0xd5, 0xdc, 0xf0,
+    0xf1, 0xf5, 0x72, 0x73, 0x8f, 0x74, 0x75, 0x96,
+    0x26, 0x2e, 0x2f, 0xa7, 0xaf, 0xb7, 0xbf, 0xc7,
+    0xcf, 0xd7, 0xdf, 0x9a, 0x40, 0x97, 0x98, 0x30,
+    0x8f, 0x1f, 0xd2, 0xd4, 0xce, 0xff, 0x4e, 0x4f,
+    0x5a, 0x5b, 0x07, 0x08, 0x0f, 0x10, 0x27, 0x2f,
+    0xee, 0xef, 0x6e, 0x6f, 0x37, 0x3d, 0x3f, 0x42,
+    0x45, 0x90, 0x91, 0x53, 0x67, 0x75, 0xc8, 0xc9,
+    0xd0, 0xd1, 0xd8, 0xd9, 0xe7, 0xfe, 0xff,
 ];
 #[rustfmt::skip]
 const SINGLETONS1U: &[(u8, u8)] = &[
@@ -184,10 +187,12 @@ const SINGLETONS1U: &[(u8, u8)] = &[
     (0x19, 13),
     (0x1c, 5),
     (0x1d, 8),
+    (0x1f, 1),
     (0x24, 1),
     (0x6a, 4),
     (0x6b, 2),
     (0xaf, 3),
+    (0xb1, 2),
     (0xbc, 2),
     (0xcf, 2),
     (0xd1, 2),
@@ -203,7 +208,7 @@ const SINGLETONS1U: &[(u8, u8)] = &[
     (0xee, 32),
     (0xf0, 4),
     (0xf8, 2),
-    (0xfa, 2),
+    (0xfa, 3),
     (0xfb, 1),
 ];
 #[rustfmt::skip]
@@ -220,18 +225,19 @@ const SINGLETONS1L: &[u8] = &[
     0x0a, 0x0b, 0x14, 0x17, 0x36, 0x39, 0x3a, 0xa8,
     0xa9, 0xd8, 0xd9, 0x09, 0x37, 0x90, 0x91, 0xa8,
     0x07, 0x0a, 0x3b, 0x3e, 0x66, 0x69, 0x8f, 0x92,
-    0x6f, 0x5f, 0xbf, 0xee, 0xef, 0x5a, 0x62, 0xf4,
-    0xfc, 0xff, 0x9a, 0x9b, 0x2e, 0x2f, 0x27, 0x28,
-    0x55, 0x9d, 0xa0, 0xa1, 0xa3, 0xa4, 0xa7, 0xa8,
-    0xad, 0xba, 0xbc, 0xc4, 0x06, 0x0b, 0x0c, 0x15,
-    0x1d, 0x3a, 0x3f, 0x45, 0x51, 0xa6, 0xa7, 0xcc,
-    0xcd, 0xa0, 0x07, 0x19, 0x1a, 0x22, 0x25, 0x3e,
-    0x3f, 0xe7, 0xec, 0xef, 0xff, 0xc5, 0xc6, 0x04,
-    0x20, 0x23, 0x25, 0x26, 0x28, 0x33, 0x38, 0x3a,
-    0x48, 0x4a, 0x4c, 0x50, 0x53, 0x55, 0x56, 0x58,
-    0x5a, 0x5c, 0x5e, 0x60, 0x63, 0x65, 0x66, 0x6b,
-    0x73, 0x78, 0x7d, 0x7f, 0x8a, 0xa4, 0xaa, 0xaf,
-    0xb0, 0xc0, 0xd0, 0xae, 0xaf, 0x6e, 0x6f, 0x93,
+    0x11, 0x6f, 0x5f, 0xbf, 0xee, 0xef, 0x5a, 0x62,
+    0xf4, 0xfc, 0xff, 0x53, 0x54, 0x9a, 0x9b, 0x2e,
+    0x2f, 0x27, 0x28, 0x55, 0x9d, 0xa0, 0xa1, 0xa3,
+    0xa4, 0xa7, 0xa8, 0xad, 0xba, 0xbc, 0xc4, 0x06,
+    0x0b, 0x0c, 0x15, 0x1d, 0x3a, 0x3f, 0x45, 0x51,
+    0xa6, 0xa7, 0xcc, 0xcd, 0xa0, 0x07, 0x19, 0x1a,
+    0x22, 0x25, 0x3e, 0x3f, 0xe7, 0xec, 0xef, 0xff,
+    0xc5, 0xc6, 0x04, 0x20, 0x23, 0x25, 0x26, 0x28,
+    0x33, 0x38, 0x3a, 0x48, 0x4a, 0x4c, 0x50, 0x53,
+    0x55, 0x56, 0x58, 0x5a, 0x5c, 0x5e, 0x60, 0x63,
+    0x65, 0x66, 0x6b, 0x73, 0x78, 0x7d, 0x7f, 0x8a,
+    0xa4, 0xaa, 0xaf, 0xb0, 0xc0, 0xd0, 0xae, 0xaf,
+    0x6e, 0x6f, 0xbe, 0x93,
 ];
 #[rustfmt::skip]
 const NORMAL0: &[u8] = &[
@@ -272,7 +278,7 @@ const NORMAL0: &[u8] = &[
     0x1b, 0x07,
     0x57, 0x07,
     0x02, 0x06,
-    0x16, 0x0d,
+    0x17, 0x0c,
     0x50, 0x04,
     0x43, 0x03,
     0x2d, 0x03,
@@ -424,8 +430,8 @@ const NORMAL1: &[u8] = &[
     0x33, 0x07,
     0x2e, 0x08,
     0x0a, 0x81, 0x26,
-    0x52, 0x4e,
-    0x28, 0x08,
+    0x52, 0x4b,
+    0x2b, 0x08,
     0x2a, 0x16,
     0x1a, 0x26,
     0x1c, 0x14,
@@ -438,7 +444,7 @@ const NORMAL1: &[u8] = &[
     0x48, 0x08,
     0x27, 0x09,
     0x75, 0x0b,
-    0x3f, 0x41,
+    0x42, 0x3e,
     0x2a, 0x06,
     0x3b, 0x05,
     0x0a, 0x06,
@@ -464,7 +470,8 @@ const NORMAL1: &[u8] = &[
     0x45, 0x1b,
     0x48, 0x08,
     0x53, 0x0d,
-    0x49, 0x81, 0x07,
+    0x49, 0x07,
+    0x0a, 0x80, 0xf6,
     0x46, 0x0a,
     0x1d, 0x03,
     0x47, 0x49,
@@ -473,14 +480,17 @@ const NORMAL1: &[u8] = &[
     0x0a, 0x06,
     0x39, 0x07,
     0x0a, 0x81, 0x36,
-    0x19, 0x80, 0xb7,
+    0x19, 0x07,
+    0x3b, 0x03,
+    0x1c, 0x56,
     0x01, 0x0f,
     0x32, 0x0d,
     0x83, 0x9b, 0x66,
     0x75, 0x0b,
     0x80, 0xc4, 0x8a, 0x4c,
     0x63, 0x0d,
-    0x84, 0x2f, 0x8f, 0xd1,
+    0x84, 0x30, 0x10,
+    0x16, 0x8f, 0xaa,
     0x82, 0x47, 0xa1, 0xb9,
     0x82, 0x39, 0x07,
     0x2a, 0x04,
@@ -498,8 +508,9 @@ const NORMAL1: &[u8] = &[
     0x97, 0xf8, 0x08,
     0x84, 0xd6, 0x2a,
     0x09, 0xa2, 0xe7,
-    0x81, 0x33, 0x2d,
-    0x03, 0x11,
+    0x81, 0x33, 0x0f,
+    0x01, 0x1d,
+    0x06, 0x0e,
     0x04, 0x08,
     0x81, 0x8c, 0x89, 0x04,
     0x6b, 0x05,
@@ -511,21 +522,26 @@ const NORMAL1: &[u8] = &[
     0x80, 0xf6, 0x0a,
     0x73, 0x08,
     0x70, 0x15,
-    0x46, 0x80, 0x9a,
+    0x46, 0x7a,
+    0x14, 0x0c,
     0x14, 0x0c,
     0x57, 0x09,
     0x19, 0x80, 0x87,
     0x81, 0x47, 0x03,
     0x85, 0x42, 0x0f,
     0x15, 0x84, 0x50,
-    0x1f, 0x80, 0xe1,
-    0x2b, 0x80, 0xd5,
+    0x1f, 0x06,
+    0x06, 0x80, 0xd5,
+    0x2b, 0x05,
+    0x3e, 0x21,
+    0x01, 0x70,
     0x2d, 0x03,
     0x1a, 0x04,
     0x02, 0x81, 0x40,
     0x1f, 0x11,
     0x3a, 0x05,
-    0x01, 0x84, 0xe0,
+    0x01, 0x81, 0xd0,
+    0x2a, 0x82, 0xe6,
     0x80, 0xf7, 0x29,
     0x4c, 0x04,
     0x0a, 0x04,
@@ -546,11 +562,11 @@ const NORMAL1: &[u8] = &[
     0x09, 0x07,
     0x02, 0x0e,
     0x06, 0x80, 0x9a,
-    0x83, 0xd8, 0x05,
-    0x10, 0x03,
+    0x83, 0xd8, 0x04,
+    0x11, 0x03,
     0x0d, 0x03,
-    0x74, 0x0c,
-    0x59, 0x07,
+    0x77, 0x04,
+    0x5f, 0x06,
     0x0c, 0x04,
     0x01, 0x0f,
     0x0c, 0x04,
@@ -559,15 +575,12 @@ const NORMAL1: &[u8] = &[
     0x28, 0x08,
     0x22, 0x4e,
     0x81, 0x54, 0x0c,
-    0x15, 0x03,
-    0x05, 0x03,
-    0x07, 0x09,
     0x1d, 0x03,
-    0x0b, 0x05,
-    0x06, 0x0a,
-    0x0a, 0x06,
-    0x08, 0x08,
-    0x07, 0x09,
+    0x09, 0x07,
+    0x36, 0x08,
+    0x0e, 0x04,
+    0x09, 0x07,
+    0x09, 0x07,
     0x80, 0xcb, 0x25,
     0x0a, 0x84, 0x06,
 ];
diff --git a/library/core/src/unicode/unicode_data.rs b/library/core/src/unicode/unicode_data.rs
index c1eff3a36e6e..bd69ca520c2e 100644
--- a/library/core/src/unicode/unicode_data.rs
+++ b/library/core/src/unicode/unicode_data.rs
@@ -1,7 +1,8 @@
 ///! This file is generated by src/tools/unicode-table-generator; do not edit manually!
 
+#[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]
 #[inline(always)]
-fn bitset_search<
+const fn bitset_search<
     const N: usize,
     const CHUNK_SIZE: usize,
     const N1: usize,
@@ -17,14 +18,18 @@ fn bitset_search<
     let bucket_idx = (needle / 64) as usize;
     let chunk_map_idx = bucket_idx / CHUNK_SIZE;
     let chunk_piece = bucket_idx % CHUNK_SIZE;
-    let chunk_idx = if let Some(&v) = chunk_idx_map.get(chunk_map_idx) {
-        v
+    // FIXME: const-hack: Revert to `slice::get` after `const_slice_index`
+    // feature stabilizes.
+    let chunk_idx = if chunk_map_idx < chunk_idx_map.len() {
+        chunk_idx_map[chunk_map_idx]
     } else {
         return false;
     };
     let idx = bitset_chunk_idx[chunk_idx as usize][chunk_piece] as usize;
-    let word = if let Some(word) = bitset_canonical.get(idx) {
-        *word
+    // FIXME: const-hack: Revert to `slice::get` after `const_slice_index`
+    // feature stabilizes.
+    let word = if idx < bitset_canonical.len() {
+        bitset_canonical[idx]
     } else {
         let (real_idx, mapping) = bitset_canonicalized[idx - bitset_canonical.len()];
         let mut word = bitset_canonical[real_idx as usize];
@@ -94,21 +99,21 @@ fn skip_search<const SOR: usize, const OFFSETS: usize>(
     offset_idx % 2 == 1
 }
 
-pub const UNICODE_VERSION: (u8, u8, u8) = (14, 0, 0);
+pub const UNICODE_VERSION: (u8, u8, u8) = (15, 0, 0);
 
 #[rustfmt::skip]
 pub mod alphabetic {
-    static SHORT_OFFSET_RUNS: [u32; 51] = [
-        706, 33559113, 876615277, 956309270, 1166025910, 1314925568, 1319120901, 1398813696,
-        1449151936, 1451271309, 1455465997, 1463867300, 1652619520, 1663105646, 1665203518,
-        1711342208, 1797326647, 1891700352, 2044795904, 2397118176, 2485199770, 2495688592,
-        2506175535, 2512471040, 2514568775, 2516674560, 2518772281, 2520870464, 2552334328,
-        2583792854, 2587996144, 2594287907, 2608968444, 2621553664, 2623656960, 2644629158,
-        2722225920, 2770461328, 2808211424, 2816601600, 2850156848, 2988572672, 3001198304,
-        3003299641, 3007499938, 3015896033, 3020093440, 3022191134, 3024289792, 3026391883,
-        3029603147,
+    static SHORT_OFFSET_RUNS: [u32; 53] = [
+        706, 33559113, 872420973, 952114966, 1161831606, 1310731264, 1314926597, 1394619392,
+        1444957632, 1447077005, 1451271693, 1459672996, 1648425216, 1658911342, 1661009214,
+        1707147904, 1793132343, 1887506048, 2040601600, 2392923872, 2481005466, 2504077200,
+        2514564144, 2520859648, 2527151687, 2529257472, 2531355193, 2533453376, 2564917240,
+        2596375766, 2600579056, 2606870819, 2621551356, 2642525184, 2644628480, 2665600678,
+        2743197440, 2791432848, 2841765072, 2850154464, 2854350336, 2887905584, 3026321408,
+        3038947040, 3041048378, 3045248674, 3053644769, 3057842176, 3059939870, 3062038528,
+        3064140619, 3066241968, 3071550384,
     ];
-    static OFFSETS: [u8; 1445] = [
+    static OFFSETS: [u8; 1465] = [
         65, 26, 6, 26, 47, 1, 10, 1, 4, 1, 5, 23, 1, 31, 1, 0, 4, 12, 14, 5, 7, 1, 1, 1, 86, 1, 42,
         5, 1, 2, 2, 4, 1, 1, 6, 1, 1, 3, 1, 1, 1, 20, 1, 83, 1, 139, 8, 166, 1, 38, 2, 1, 6, 41, 39,
         14, 1, 1, 1, 2, 1, 2, 1, 1, 8, 27, 4, 4, 29, 11, 5, 56, 1, 7, 14, 102, 1, 8, 4, 8, 4, 3, 10,
@@ -118,50 +123,51 @@ pub mod alphabetic {
         2, 1, 2, 4, 5, 4, 2, 2, 2, 4, 1, 7, 4, 1, 1, 17, 6, 11, 3, 1, 9, 1, 3, 1, 22, 1, 7, 1, 2, 1,
         5, 3, 9, 1, 3, 1, 2, 3, 1, 15, 4, 21, 4, 4, 3, 1, 8, 2, 2, 2, 22, 1, 7, 1, 2, 1, 5, 3, 8, 2,
         2, 2, 2, 9, 2, 4, 2, 1, 5, 13, 1, 16, 2, 1, 6, 3, 3, 1, 4, 3, 2, 1, 1, 1, 2, 3, 2, 3, 3, 3,
-        12, 4, 5, 3, 3, 1, 3, 3, 1, 6, 1, 40, 4, 1, 8, 1, 3, 1, 23, 1, 16, 3, 8, 1, 3, 1, 3, 8, 2,
-        1, 3, 2, 1, 2, 4, 28, 4, 1, 8, 1, 3, 1, 23, 1, 10, 1, 5, 3, 8, 1, 3, 1, 3, 8, 2, 6, 2, 1, 4,
-        13, 2, 13, 13, 1, 3, 1, 41, 2, 8, 1, 3, 1, 3, 1, 1, 5, 4, 7, 5, 22, 6, 1, 3, 1, 18, 3, 24,
-        1, 9, 1, 1, 2, 7, 8, 6, 1, 1, 1, 8, 18, 2, 13, 58, 5, 7, 6, 1, 51, 2, 1, 1, 1, 5, 1, 24, 1,
-        1, 1, 19, 1, 3, 2, 5, 1, 1, 6, 1, 14, 4, 32, 1, 63, 8, 1, 36, 4, 17, 6, 16, 1, 36, 67, 55,
-        1, 1, 2, 5, 16, 64, 10, 4, 2, 38, 1, 1, 5, 1, 2, 43, 1, 0, 1, 4, 2, 7, 1, 1, 1, 4, 2, 41, 1,
-        4, 2, 33, 1, 4, 2, 7, 1, 1, 1, 4, 2, 15, 1, 57, 1, 4, 2, 67, 37, 16, 16, 86, 2, 6, 3, 0, 2,
-        17, 1, 26, 5, 75, 3, 11, 7, 20, 11, 21, 12, 20, 12, 13, 1, 3, 1, 2, 12, 52, 2, 19, 14, 1, 4,
-        1, 67, 89, 7, 43, 5, 70, 10, 31, 1, 12, 4, 9, 23, 30, 2, 5, 11, 44, 4, 26, 54, 28, 4, 63, 2,
-        20, 50, 1, 23, 2, 11, 3, 49, 52, 1, 15, 1, 8, 51, 42, 2, 4, 10, 44, 1, 11, 14, 55, 22, 3,
-        10, 36, 2, 9, 7, 43, 2, 3, 41, 4, 1, 6, 1, 2, 3, 1, 5, 192, 39, 14, 11, 0, 2, 6, 2, 38, 2,
-        6, 2, 8, 1, 1, 1, 1, 1, 1, 1, 31, 2, 53, 1, 7, 1, 1, 3, 3, 1, 7, 3, 4, 2, 6, 4, 13, 5, 3, 1,
-        7, 116, 1, 13, 1, 16, 13, 101, 1, 4, 1, 2, 10, 1, 1, 3, 5, 6, 1, 1, 1, 1, 1, 1, 4, 1, 11, 2,
-        4, 5, 5, 4, 1, 17, 41, 0, 52, 0, 229, 6, 4, 3, 2, 12, 38, 1, 1, 5, 1, 2, 56, 7, 1, 16, 23,
-        9, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 32, 47, 1, 0, 3, 25, 9, 7, 5, 2, 5, 4,
-        86, 6, 3, 1, 90, 1, 4, 5, 43, 1, 94, 17, 32, 48, 16, 0, 0, 64, 0, 67, 46, 2, 0, 3, 16, 10,
-        2, 20, 47, 5, 8, 3, 113, 39, 9, 2, 103, 2, 64, 5, 2, 1, 1, 1, 5, 24, 20, 1, 33, 24, 52, 12,
-        68, 1, 1, 44, 6, 3, 1, 1, 3, 10, 33, 5, 35, 13, 29, 3, 51, 1, 12, 15, 1, 16, 16, 10, 5, 1,
-        55, 9, 14, 18, 23, 3, 69, 1, 1, 1, 1, 24, 3, 2, 16, 2, 4, 11, 6, 2, 6, 2, 6, 9, 7, 1, 7, 1,
-        43, 1, 14, 6, 123, 21, 0, 12, 23, 4, 49, 0, 0, 2, 106, 38, 7, 12, 5, 5, 12, 1, 13, 1, 5, 1,
-        1, 1, 2, 1, 2, 1, 108, 33, 0, 18, 64, 2, 54, 40, 12, 116, 5, 1, 135, 36, 26, 6, 26, 11, 89,
-        3, 6, 2, 6, 2, 6, 2, 3, 35, 12, 1, 26, 1, 19, 1, 2, 1, 15, 2, 14, 34, 123, 69, 53, 0, 29, 3,
+        12, 4, 5, 3, 3, 1, 3, 3, 1, 6, 1, 40, 13, 1, 3, 1, 23, 1, 16, 3, 8, 1, 3, 1, 3, 8, 2, 1, 3,
+        2, 1, 2, 4, 28, 4, 1, 8, 1, 3, 1, 23, 1, 10, 1, 5, 3, 8, 1, 3, 1, 3, 8, 2, 6, 2, 1, 4, 13,
+        3, 12, 13, 1, 3, 1, 41, 2, 8, 1, 3, 1, 3, 1, 1, 5, 4, 7, 5, 22, 6, 1, 3, 1, 18, 3, 24, 1, 9,
+        1, 1, 2, 7, 8, 6, 1, 1, 1, 8, 18, 2, 13, 58, 5, 7, 6, 1, 51, 2, 1, 1, 1, 5, 1, 24, 1, 1, 1,
+        19, 1, 3, 2, 5, 1, 1, 6, 1, 14, 4, 32, 1, 63, 8, 1, 36, 4, 19, 4, 16, 1, 36, 67, 55, 1, 1,
+        2, 5, 16, 64, 10, 4, 2, 38, 1, 1, 5, 1, 2, 43, 1, 0, 1, 4, 2, 7, 1, 1, 1, 4, 2, 41, 1, 4, 2,
+        33, 1, 4, 2, 7, 1, 1, 1, 4, 2, 15, 1, 57, 1, 4, 2, 67, 37, 16, 16, 86, 2, 6, 3, 0, 2, 17, 1,
+        26, 5, 75, 3, 11, 7, 20, 11, 21, 12, 20, 12, 13, 1, 3, 1, 2, 12, 52, 2, 19, 14, 1, 4, 1, 67,
+        89, 7, 43, 5, 70, 10, 31, 1, 12, 4, 9, 23, 30, 2, 5, 11, 44, 4, 26, 54, 28, 4, 63, 2, 20,
+        50, 1, 23, 2, 11, 3, 49, 52, 1, 15, 1, 8, 51, 42, 2, 4, 10, 44, 1, 11, 14, 55, 22, 3, 10,
+        36, 2, 9, 7, 43, 2, 3, 41, 4, 1, 6, 1, 2, 3, 1, 5, 192, 39, 14, 11, 0, 2, 6, 2, 38, 2, 6, 2,
+        8, 1, 1, 1, 1, 1, 1, 1, 31, 2, 53, 1, 7, 1, 1, 3, 3, 1, 7, 3, 4, 2, 6, 4, 13, 5, 3, 1, 7,
+        116, 1, 13, 1, 16, 13, 101, 1, 4, 1, 2, 10, 1, 1, 3, 5, 6, 1, 1, 1, 1, 1, 1, 4, 1, 11, 2, 4,
+        5, 5, 4, 1, 17, 41, 0, 52, 0, 229, 6, 4, 3, 2, 12, 38, 1, 1, 5, 1, 2, 56, 7, 1, 16, 23, 9,
+        7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 32, 47, 1, 0, 3, 25, 9, 7, 5, 2, 5, 4, 86,
+        6, 3, 1, 90, 1, 4, 5, 43, 1, 94, 17, 32, 48, 16, 0, 0, 64, 0, 67, 46, 2, 0, 3, 16, 10, 2,
+        20, 47, 5, 8, 3, 113, 39, 9, 2, 103, 2, 64, 5, 2, 1, 1, 1, 5, 24, 20, 1, 33, 24, 52, 12, 68,
+        1, 1, 44, 6, 3, 1, 1, 3, 10, 33, 5, 35, 13, 29, 3, 51, 1, 12, 15, 1, 16, 16, 10, 5, 1, 55,
+        9, 14, 18, 23, 3, 69, 1, 1, 1, 1, 24, 3, 2, 16, 2, 4, 11, 6, 2, 6, 2, 6, 9, 7, 1, 7, 1, 43,
+        1, 14, 6, 123, 21, 0, 12, 23, 4, 49, 0, 0, 2, 106, 38, 7, 12, 5, 5, 12, 1, 13, 1, 5, 1, 1,
+        1, 2, 1, 2, 1, 108, 33, 0, 18, 64, 2, 54, 40, 12, 116, 5, 1, 135, 36, 26, 6, 26, 11, 89, 3,
+        6, 2, 6, 2, 6, 2, 3, 35, 12, 1, 26, 1, 19, 1, 2, 1, 15, 2, 14, 34, 123, 69, 53, 0, 29, 3,
         49, 47, 32, 13, 30, 5, 43, 5, 30, 2, 36, 4, 8, 1, 5, 42, 158, 18, 36, 4, 36, 4, 40, 8, 52,
         12, 11, 1, 15, 1, 7, 1, 2, 1, 11, 1, 15, 1, 7, 1, 2, 67, 0, 9, 22, 10, 8, 24, 6, 1, 42, 1,
         9, 69, 6, 2, 1, 1, 44, 1, 2, 3, 1, 2, 23, 10, 23, 9, 31, 65, 19, 1, 2, 10, 22, 10, 26, 70,
         56, 6, 2, 64, 4, 1, 2, 5, 8, 1, 3, 1, 29, 42, 29, 3, 29, 35, 8, 1, 28, 27, 54, 10, 22, 10,
         19, 13, 18, 110, 73, 55, 51, 13, 51, 13, 40, 0, 42, 1, 2, 3, 2, 78, 29, 10, 1, 8, 22, 42,
-        18, 46, 21, 27, 23, 9, 70, 43, 5, 12, 55, 9, 1, 13, 25, 23, 51, 17, 4, 8, 35, 3, 1, 9, 64,
-        1, 4, 9, 2, 10, 1, 1, 1, 35, 18, 1, 34, 2, 1, 6, 1, 65, 7, 1, 1, 1, 4, 1, 15, 1, 10, 7, 57,
+        18, 46, 21, 27, 23, 9, 70, 43, 5, 10, 57, 9, 1, 13, 25, 23, 51, 17, 4, 8, 35, 3, 1, 9, 64,
+        1, 4, 9, 2, 10, 1, 1, 1, 35, 18, 1, 34, 2, 1, 6, 4, 62, 7, 1, 1, 1, 4, 1, 15, 1, 10, 7, 57,
         23, 4, 1, 8, 2, 2, 2, 22, 1, 7, 1, 2, 1, 5, 3, 8, 2, 2, 2, 2, 3, 1, 6, 1, 5, 7, 156, 66, 1,
         3, 1, 4, 20, 3, 30, 66, 2, 2, 1, 1, 184, 54, 2, 7, 25, 6, 34, 63, 1, 1, 3, 1, 59, 54, 2, 1,
         71, 27, 2, 14, 21, 7, 185, 57, 103, 64, 31, 8, 2, 1, 2, 8, 1, 2, 1, 30, 1, 2, 2, 2, 2, 4,
         93, 8, 2, 46, 2, 6, 1, 1, 1, 2, 27, 51, 2, 10, 17, 72, 5, 1, 18, 73, 0, 9, 1, 45, 1, 7, 1,
         1, 49, 30, 2, 22, 1, 14, 73, 7, 1, 2, 1, 44, 3, 1, 1, 2, 1, 3, 1, 1, 2, 2, 24, 6, 1, 2, 1,
-        37, 1, 2, 1, 4, 1, 1, 0, 23, 185, 1, 79, 0, 102, 111, 17, 196, 0, 97, 15, 0, 0, 0, 0, 0, 7,
-        31, 17, 79, 17, 30, 18, 48, 16, 4, 31, 21, 5, 19, 0, 64, 128, 75, 4, 57, 7, 17, 64, 2, 1, 1,
-        12, 2, 14, 0, 8, 0, 42, 9, 0, 4, 1, 7, 1, 2, 1, 0, 45, 3, 17, 4, 8, 0, 0, 107, 5, 13, 3, 9,
-        7, 10, 4, 1, 0, 85, 1, 71, 1, 2, 2, 1, 2, 2, 2, 4, 1, 12, 1, 1, 1, 7, 1, 65, 1, 4, 2, 8, 1,
-        7, 1, 28, 1, 4, 1, 5, 1, 1, 3, 7, 1, 0, 2, 25, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1,
-        25, 1, 31, 1, 25, 1, 8, 0, 31, 225, 7, 1, 17, 2, 7, 1, 2, 1, 5, 213, 45, 10, 7, 16, 1, 0,
-        30, 18, 44, 0, 7, 1, 4, 1, 2, 1, 15, 1, 197, 59, 68, 3, 1, 3, 1, 0, 4, 1, 27, 1, 2, 1, 1, 2,
-        1, 1, 10, 1, 4, 1, 1, 1, 1, 6, 1, 4, 1, 1, 1, 1, 1, 1, 3, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1,
-        1, 1, 1, 1, 2, 1, 1, 2, 4, 1, 7, 1, 4, 1, 4, 1, 1, 1, 10, 1, 17, 5, 3, 1, 5, 1, 17, 0, 26,
-        6, 26, 6, 26, 0, 0, 32, 0, 7, 222, 2, 0, 14, 0, 0, 0, 0, 0, 0,
+        37, 1, 2, 1, 4, 1, 1, 0, 23, 9, 17, 1, 41, 3, 3, 111, 1, 79, 0, 102, 111, 17, 196, 0, 97,
+        15, 0, 17, 6, 0, 0, 0, 0, 7, 31, 17, 79, 17, 30, 18, 48, 16, 4, 31, 21, 5, 19, 0, 64, 128,
+        75, 4, 57, 7, 17, 64, 2, 1, 1, 12, 2, 14, 0, 8, 0, 42, 9, 0, 4, 1, 7, 1, 2, 1, 0, 15, 1, 29,
+        3, 2, 1, 14, 4, 8, 0, 0, 107, 5, 13, 3, 9, 7, 10, 4, 1, 0, 85, 1, 71, 1, 2, 2, 1, 2, 2, 2,
+        4, 1, 12, 1, 1, 1, 7, 1, 65, 1, 4, 2, 8, 1, 7, 1, 28, 1, 4, 1, 5, 1, 1, 3, 7, 1, 0, 2, 25,
+        1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 8, 0, 31, 6, 6, 213, 7, 1,
+        17, 2, 7, 1, 2, 1, 5, 5, 62, 33, 1, 112, 45, 10, 7, 16, 1, 0, 30, 18, 44, 0, 28, 0, 7, 1, 4,
+        1, 2, 1, 15, 1, 197, 59, 68, 3, 1, 3, 1, 0, 4, 1, 27, 1, 2, 1, 1, 2, 1, 1, 10, 1, 4, 1, 1,
+        1, 1, 6, 1, 4, 1, 1, 1, 1, 1, 1, 3, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2,
+        4, 1, 7, 1, 4, 1, 4, 1, 1, 1, 10, 1, 17, 5, 3, 1, 5, 1, 17, 0, 26, 6, 26, 6, 26, 0, 0, 32,
+        0, 6, 222, 2, 0, 14, 0, 0, 0, 0, 0, 5, 0, 0,
     ];
     pub fn lookup(c: char) -> bool {
         super::skip_search(
@@ -177,11 +183,11 @@ pub mod case_ignorable {
     static SHORT_OFFSET_RUNS: [u32; 35] = [
         688, 44045149, 572528402, 576724925, 807414908, 878718981, 903913493, 929080568, 933275148,
         937491230, 1138818560, 1147208189, 1210124160, 1222707713, 1235291428, 1260457643,
-        1264654383, 1491147067, 1499536432, 1558257395, 1621177392, 1625385712, 1629581135,
-        1642180592, 1658961053, 1671548672, 1679937895, 1688328704, 1709301760, 1734467888,
-        1755439790, 1759635664, 1768027131, 1777205249, 1782514160,
+        1264654383, 1499535675, 1507925040, 1566646003, 1629566000, 1650551536, 1658941263,
+        1671540720, 1688321181, 1700908800, 1709298023, 1717688832, 1738661888, 1763828398,
+        1797383403, 1805773008, 1809970171, 1819148289, 1824457200,
     ];
-    static OFFSETS: [u8; 855] = [
+    static OFFSETS: [u8; 875] = [
         39, 1, 6, 1, 11, 1, 35, 1, 1, 1, 71, 1, 4, 1, 1, 1, 4, 1, 2, 2, 0, 192, 4, 2, 4, 1, 9, 2,
         1, 1, 251, 7, 207, 1, 5, 1, 49, 45, 1, 1, 1, 2, 1, 2, 1, 1, 44, 1, 11, 6, 10, 11, 1, 1, 35,
         1, 10, 21, 16, 1, 101, 8, 1, 10, 1, 4, 33, 1, 1, 1, 30, 27, 91, 11, 58, 11, 4, 1, 2, 1, 24,
@@ -190,7 +196,7 @@ pub mod case_ignorable {
         57, 1, 4, 5, 1, 2, 4, 1, 20, 2, 22, 6, 1, 1, 58, 1, 2, 1, 1, 4, 8, 1, 7, 2, 11, 2, 30, 1,
         61, 1, 12, 1, 50, 1, 3, 1, 55, 1, 1, 3, 5, 3, 1, 4, 7, 2, 11, 2, 29, 1, 58, 1, 2, 1, 6, 1,
         5, 2, 20, 2, 28, 2, 57, 2, 4, 4, 8, 1, 20, 2, 29, 1, 72, 1, 7, 3, 1, 1, 90, 1, 2, 7, 11, 9,
-        98, 1, 2, 9, 9, 1, 1, 6, 74, 2, 27, 1, 1, 1, 1, 1, 55, 14, 1, 5, 1, 2, 5, 11, 1, 36, 9, 1,
+        98, 1, 2, 9, 9, 1, 1, 7, 73, 2, 27, 1, 1, 1, 1, 1, 55, 14, 1, 5, 1, 2, 5, 11, 1, 36, 9, 1,
         102, 4, 1, 6, 1, 2, 2, 2, 25, 2, 4, 3, 16, 4, 13, 1, 2, 2, 6, 1, 15, 1, 94, 1, 0, 3, 0, 3,
         29, 2, 30, 2, 30, 2, 64, 2, 1, 7, 8, 1, 2, 11, 3, 1, 5, 1, 45, 5, 51, 1, 65, 2, 34, 1, 118,
         3, 4, 2, 9, 1, 6, 3, 219, 2, 2, 1, 58, 1, 1, 7, 1, 1, 1, 1, 2, 8, 6, 10, 2, 1, 39, 1, 8, 31,
@@ -204,15 +210,16 @@ pub mod case_ignorable {
         1, 1, 27, 1, 14, 2, 5, 2, 1, 1, 100, 5, 9, 3, 121, 1, 2, 1, 4, 1, 0, 1, 147, 17, 0, 16, 3,
         1, 12, 16, 34, 1, 2, 1, 169, 1, 7, 1, 6, 1, 11, 1, 35, 1, 1, 1, 47, 1, 45, 2, 67, 1, 21, 3,
         0, 1, 226, 1, 149, 5, 0, 6, 1, 42, 1, 9, 0, 3, 1, 2, 5, 4, 40, 3, 4, 1, 165, 2, 0, 4, 0, 2,
-        153, 11, 49, 4, 123, 1, 54, 15, 41, 1, 2, 2, 10, 3, 49, 4, 2, 2, 2, 1, 4, 1, 10, 1, 50, 3,
-        36, 5, 1, 8, 62, 1, 12, 2, 52, 9, 10, 4, 2, 1, 95, 3, 2, 1, 1, 2, 6, 1, 160, 1, 3, 8, 21, 2,
-        57, 2, 3, 1, 37, 7, 3, 5, 195, 8, 2, 3, 1, 1, 23, 1, 84, 6, 1, 1, 4, 2, 1, 2, 238, 4, 6, 2,
-        1, 2, 27, 2, 85, 8, 2, 1, 1, 2, 106, 1, 1, 1, 2, 6, 1, 1, 101, 3, 2, 4, 1, 5, 0, 9, 1, 2, 0,
-        2, 1, 1, 4, 1, 144, 4, 2, 2, 4, 1, 32, 10, 40, 6, 2, 4, 8, 1, 9, 6, 2, 3, 46, 13, 1, 2, 0,
-        7, 1, 6, 1, 1, 82, 22, 2, 7, 1, 2, 1, 2, 122, 6, 3, 1, 1, 2, 1, 7, 1, 1, 72, 2, 3, 1, 1, 1,
-        0, 2, 0, 9, 0, 5, 59, 7, 9, 4, 0, 1, 63, 17, 64, 2, 1, 2, 0, 4, 1, 7, 1, 2, 0, 2, 1, 4, 0,
-        46, 2, 23, 0, 3, 9, 16, 2, 7, 30, 4, 148, 3, 0, 55, 4, 50, 8, 1, 14, 1, 22, 5, 1, 15, 0, 7,
-        1, 17, 2, 7, 1, 2, 1, 5, 0, 14, 0, 1, 61, 4, 0, 7, 109, 8, 0, 5, 0, 1, 30, 96, 128, 240, 0,
+        80, 3, 70, 11, 49, 4, 123, 1, 54, 15, 41, 1, 2, 2, 10, 3, 49, 4, 2, 2, 2, 1, 4, 1, 10, 1,
+        50, 3, 36, 5, 1, 8, 62, 1, 12, 2, 52, 9, 10, 4, 2, 1, 95, 3, 2, 1, 1, 2, 6, 1, 2, 1, 157, 1,
+        3, 8, 21, 2, 57, 2, 3, 1, 37, 7, 3, 5, 195, 8, 2, 3, 1, 1, 23, 1, 84, 6, 1, 1, 4, 2, 1, 2,
+        238, 4, 6, 2, 1, 2, 27, 2, 85, 8, 2, 1, 1, 2, 106, 1, 1, 1, 2, 6, 1, 1, 101, 3, 2, 4, 1, 5,
+        0, 9, 1, 2, 0, 2, 1, 1, 4, 1, 144, 4, 2, 2, 4, 1, 32, 10, 40, 6, 2, 4, 8, 1, 9, 6, 2, 3, 46,
+        13, 1, 2, 0, 7, 1, 6, 1, 1, 82, 22, 2, 7, 1, 2, 1, 2, 122, 6, 3, 1, 1, 2, 1, 7, 1, 1, 72, 2,
+        3, 1, 1, 1, 0, 2, 11, 2, 52, 5, 5, 1, 1, 1, 0, 17, 6, 15, 0, 5, 59, 7, 9, 4, 0, 1, 63, 17,
+        64, 2, 1, 2, 0, 4, 1, 7, 1, 2, 0, 2, 1, 4, 0, 46, 2, 23, 0, 3, 9, 16, 2, 7, 30, 4, 148, 3,
+        0, 55, 4, 50, 8, 1, 14, 1, 22, 5, 1, 15, 0, 7, 1, 17, 2, 7, 1, 2, 1, 5, 5, 62, 33, 1, 160,
+        14, 0, 1, 61, 4, 0, 5, 0, 7, 109, 8, 0, 5, 0, 1, 30, 96, 128, 240, 0,
     ];
     pub fn lookup(c: char) -> bool {
         super::skip_search(
@@ -225,24 +232,24 @@ pub mod case_ignorable {
 
 #[rustfmt::skip]
 pub mod cased {
-    static SHORT_OFFSET_RUNS: [u32; 21] = [
+    static SHORT_OFFSET_RUNS: [u32; 22] = [
         4256, 115348384, 136322176, 144711446, 163587254, 320875520, 325101120, 350268208,
         392231680, 404815649, 413205504, 421595008, 467733632, 484513952, 492924480, 497144832,
-        501339814, 578936576, 627173632, 635564336, 640872842,
+        501339814, 578936576, 627171376, 639756544, 643952944, 649261450,
     ];
-    static OFFSETS: [u8; 311] = [
+    static OFFSETS: [u8; 315] = [
         65, 26, 6, 26, 47, 1, 10, 1, 4, 1, 5, 23, 1, 31, 1, 195, 1, 4, 4, 208, 1, 36, 7, 2, 30, 5,
         96, 1, 42, 4, 2, 2, 2, 4, 1, 1, 6, 1, 1, 3, 1, 1, 1, 20, 1, 83, 1, 139, 8, 166, 1, 38, 9,
-        41, 0, 38, 1, 1, 5, 1, 2, 43, 2, 3, 0, 86, 2, 6, 0, 9, 7, 43, 2, 3, 64, 192, 64, 0, 2, 6, 2,
+        41, 0, 38, 1, 1, 5, 1, 2, 43, 1, 4, 0, 86, 2, 6, 0, 9, 7, 43, 2, 3, 64, 192, 64, 0, 2, 6, 2,
         38, 2, 6, 2, 8, 1, 1, 1, 1, 1, 1, 1, 31, 2, 53, 1, 7, 1, 1, 3, 3, 1, 7, 3, 4, 2, 6, 4, 13,
         5, 3, 1, 7, 116, 1, 13, 1, 16, 13, 101, 1, 4, 1, 2, 10, 1, 1, 3, 5, 6, 1, 1, 1, 1, 1, 1, 4,
         1, 6, 4, 1, 2, 4, 5, 5, 4, 1, 17, 32, 3, 2, 0, 52, 0, 229, 6, 4, 3, 2, 12, 38, 1, 1, 5, 1,
-        0, 46, 18, 30, 132, 102, 3, 4, 1, 59, 5, 2, 1, 1, 1, 5, 27, 2, 1, 3, 0, 43, 1, 13, 7, 80, 0,
+        0, 46, 18, 30, 132, 102, 3, 4, 1, 59, 5, 2, 1, 1, 1, 5, 24, 5, 1, 3, 0, 43, 1, 14, 6, 80, 0,
         7, 12, 5, 0, 26, 6, 26, 0, 80, 96, 36, 4, 36, 116, 11, 1, 15, 1, 7, 1, 2, 1, 11, 1, 15, 1,
         7, 1, 2, 0, 1, 2, 3, 1, 42, 1, 9, 0, 51, 13, 51, 0, 64, 0, 64, 0, 85, 1, 71, 1, 2, 2, 1, 2,
         2, 2, 4, 1, 12, 1, 1, 1, 7, 1, 65, 1, 4, 2, 8, 1, 7, 1, 28, 1, 4, 1, 5, 1, 1, 3, 7, 1, 0, 2,
-        25, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 8, 0, 10, 1, 20, 0,
-        68, 0, 26, 6, 26, 6, 26, 0,
+        25, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 31, 1, 25, 1, 8, 0, 10, 1, 20, 6, 6,
+        0, 62, 0, 68, 0, 26, 6, 26, 6, 26, 0,
     ];
     pub fn lookup(c: char) -> bool {
         super::skip_search(
@@ -272,14 +279,14 @@ pub mod cc {
 
 #[rustfmt::skip]
 pub mod grapheme_extend {
-    static SHORT_OFFSET_RUNS: [u32; 32] = [
+    static SHORT_OFFSET_RUNS: [u32; 33] = [
         768, 2098307, 6292881, 10490717, 522196754, 526393356, 731917551, 740306986, 752920175,
         761309186, 778107678, 908131840, 912326558, 920715773, 924912129, 937495844, 962662059,
-        966858799, 1205935152, 1277239027, 1340173040, 1344368463, 1352776861, 1365364480,
-        1369559397, 1377950208, 1407311872, 1432478000, 1453449902, 1457645776, 1466826784,
-        1476329968,
+        966858799, 1214323760, 1285627635, 1348547648, 1369533168, 1377922895, 1386331293,
+        1398918912, 1403113829, 1411504640, 1440866304, 1466032814, 1495393516, 1503783120,
+        1508769824, 1518273008,
     ];
-    static OFFSETS: [u8; 707] = [
+    static OFFSETS: [u8; 727] = [
         0, 112, 0, 7, 0, 45, 1, 1, 1, 2, 1, 2, 1, 1, 72, 11, 48, 21, 16, 1, 101, 7, 2, 6, 2, 2, 1,
         4, 35, 1, 30, 27, 91, 11, 58, 9, 9, 1, 24, 4, 1, 9, 1, 3, 1, 5, 43, 3, 60, 8, 42, 24, 1, 32,
         55, 1, 1, 1, 4, 8, 4, 1, 3, 7, 10, 2, 29, 1, 58, 1, 1, 1, 2, 4, 8, 1, 9, 1, 10, 2, 26, 1, 2,
@@ -287,7 +294,7 @@ pub mod grapheme_extend {
         1, 1, 58, 1, 1, 2, 1, 4, 8, 1, 7, 3, 10, 2, 30, 1, 59, 1, 1, 1, 12, 1, 9, 1, 40, 1, 3, 1,
         55, 1, 1, 3, 5, 3, 1, 4, 7, 2, 11, 2, 29, 1, 58, 1, 2, 1, 2, 1, 3, 1, 5, 2, 7, 2, 11, 2, 28,
         2, 57, 2, 1, 1, 2, 4, 8, 1, 9, 1, 10, 2, 29, 1, 72, 1, 4, 1, 2, 3, 1, 1, 8, 1, 81, 1, 2, 7,
-        12, 8, 98, 1, 2, 9, 11, 6, 74, 2, 27, 1, 1, 1, 1, 1, 55, 14, 1, 5, 1, 2, 5, 11, 1, 36, 9, 1,
+        12, 8, 98, 1, 2, 9, 11, 7, 73, 2, 27, 1, 1, 1, 1, 1, 55, 14, 1, 5, 1, 2, 5, 11, 1, 36, 9, 1,
         102, 4, 1, 6, 1, 2, 2, 2, 25, 2, 4, 3, 16, 4, 13, 1, 2, 2, 6, 1, 15, 1, 0, 3, 0, 3, 29, 2,
         30, 2, 30, 2, 64, 2, 1, 7, 8, 1, 2, 11, 9, 1, 45, 3, 1, 1, 117, 2, 34, 1, 118, 3, 4, 2, 9,
         1, 6, 3, 219, 2, 2, 1, 58, 1, 1, 7, 1, 1, 1, 1, 2, 8, 6, 10, 2, 1, 48, 31, 49, 4, 48, 7, 1,
@@ -296,16 +303,17 @@ pub mod grapheme_extend {
         4, 1, 10, 32, 2, 80, 2, 0, 1, 3, 1, 4, 1, 25, 2, 5, 1, 151, 2, 26, 18, 13, 1, 38, 8, 25, 11,
         46, 3, 48, 1, 2, 4, 2, 2, 39, 1, 67, 6, 2, 2, 2, 2, 12, 1, 8, 1, 47, 1, 51, 1, 1, 3, 2, 2,
         5, 2, 1, 1, 42, 2, 8, 1, 238, 1, 2, 1, 4, 1, 0, 1, 0, 16, 16, 16, 0, 2, 0, 1, 226, 1, 149,
-        5, 0, 3, 1, 2, 5, 4, 40, 3, 4, 1, 165, 2, 0, 4, 0, 2, 153, 11, 49, 4, 123, 1, 54, 15, 41, 1,
-        2, 2, 10, 3, 49, 4, 2, 2, 7, 1, 61, 3, 36, 5, 1, 8, 62, 1, 12, 2, 52, 9, 10, 4, 2, 1, 95, 3,
-        2, 1, 1, 2, 6, 1, 160, 1, 3, 8, 21, 2, 57, 2, 1, 1, 1, 1, 22, 1, 14, 7, 3, 5, 195, 8, 2, 3,
-        1, 1, 23, 1, 81, 1, 2, 6, 1, 1, 2, 1, 1, 2, 1, 2, 235, 1, 2, 4, 6, 2, 1, 2, 27, 2, 85, 8, 2,
-        1, 1, 2, 106, 1, 1, 1, 2, 6, 1, 1, 101, 3, 2, 4, 1, 5, 0, 9, 1, 2, 245, 1, 10, 2, 1, 1, 4,
-        1, 144, 4, 2, 2, 4, 1, 32, 10, 40, 6, 2, 4, 8, 1, 9, 6, 2, 3, 46, 13, 1, 2, 0, 7, 1, 6, 1,
-        1, 82, 22, 2, 7, 1, 2, 1, 2, 122, 6, 3, 1, 1, 2, 1, 7, 1, 1, 72, 2, 3, 1, 1, 1, 0, 2, 0, 5,
-        59, 7, 0, 1, 63, 4, 81, 1, 0, 2, 0, 46, 2, 23, 0, 1, 1, 3, 4, 5, 8, 8, 2, 7, 30, 4, 148, 3,
-        0, 55, 4, 50, 8, 1, 14, 1, 22, 5, 1, 15, 0, 7, 1, 17, 2, 7, 1, 2, 1, 5, 0, 7, 0, 1, 61, 4,
-        0, 7, 109, 7, 0, 96, 128, 240, 0,
+        5, 0, 3, 1, 2, 5, 4, 40, 3, 4, 1, 165, 2, 0, 4, 0, 2, 80, 3, 70, 11, 49, 4, 123, 1, 54, 15,
+        41, 1, 2, 2, 10, 3, 49, 4, 2, 2, 7, 1, 61, 3, 36, 5, 1, 8, 62, 1, 12, 2, 52, 9, 10, 4, 2, 1,
+        95, 3, 2, 1, 1, 2, 6, 1, 2, 1, 157, 1, 3, 8, 21, 2, 57, 2, 1, 1, 1, 1, 22, 1, 14, 7, 3, 5,
+        195, 8, 2, 3, 1, 1, 23, 1, 81, 1, 2, 6, 1, 1, 2, 1, 1, 2, 1, 2, 235, 1, 2, 4, 6, 2, 1, 2,
+        27, 2, 85, 8, 2, 1, 1, 2, 106, 1, 1, 1, 2, 6, 1, 1, 101, 3, 2, 4, 1, 5, 0, 9, 1, 2, 245, 1,
+        10, 2, 1, 1, 4, 1, 144, 4, 2, 2, 4, 1, 32, 10, 40, 6, 2, 4, 8, 1, 9, 6, 2, 3, 46, 13, 1, 2,
+        0, 7, 1, 6, 1, 1, 82, 22, 2, 7, 1, 2, 1, 2, 122, 6, 3, 1, 1, 2, 1, 7, 1, 1, 72, 2, 3, 1, 1,
+        1, 0, 2, 11, 2, 52, 5, 5, 1, 1, 1, 0, 1, 6, 15, 0, 5, 59, 7, 0, 1, 63, 4, 81, 1, 0, 2, 0,
+        46, 2, 23, 0, 1, 1, 3, 4, 5, 8, 8, 2, 7, 30, 4, 148, 3, 0, 55, 4, 50, 8, 1, 14, 1, 22, 5, 1,
+        15, 0, 7, 1, 17, 2, 7, 1, 2, 1, 5, 100, 1, 160, 7, 0, 1, 61, 4, 0, 4, 0, 7, 109, 7, 0, 96,
+        128, 240, 0,
     ];
     pub fn lookup(c: char) -> bool {
         super::skip_search(
@@ -318,54 +326,56 @@ pub mod grapheme_extend {
 
 #[rustfmt::skip]
 pub mod lowercase {
-    static BITSET_CHUNKS_MAP: [u8; 123] = [
+    const BITSET_CHUNKS_MAP: &'static [u8; 123] = &[
         14, 17, 0, 0, 9, 0, 0, 12, 13, 10, 0, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         0, 0, 0, 4, 1, 0, 15, 0, 8, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-        0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 18, 0,
-        3, 0, 0, 7,
+        0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 19, 0,
+        3, 18, 0, 7,
     ];
-    static BITSET_INDEX_CHUNKS: [[u8; 16]; 19] = [
+    const BITSET_INDEX_CHUNKS: &'static [[u8; 16]; 20] = &[
         [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
         [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 59, 0, 0],
         [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 14, 55, 0],
-        [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 41, 0, 0, 0],
-        [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 43, 0, 0, 0],
+        [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0],
+        [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 44, 0, 0, 0],
         [0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0, 0],
-        [0, 0, 0, 0, 0, 0, 0, 0, 0, 65, 42, 0, 50, 46, 48, 32],
+        [0, 0, 0, 0, 0, 0, 0, 0, 0, 65, 43, 0, 51, 47, 49, 33],
         [0, 0, 0, 0, 10, 56, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [0, 0, 0, 53, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 26],
+        [0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+        [0, 0, 0, 19, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 27],
         [0, 0, 0, 60, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [0, 0, 0, 70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [0, 0, 57, 0, 55, 55, 55, 0, 21, 21, 67, 21, 35, 24, 23, 36],
-        [0, 5, 74, 0, 28, 15, 72, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [0, 64, 33, 17, 22, 51, 52, 47, 45, 8, 34, 40, 0, 27, 13, 30],
-        [11, 58, 0, 4, 0, 0, 29, 0, 0, 0, 0, 0, 0, 0, 31, 0],
-        [16, 25, 21, 37, 38, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [16, 49, 2, 20, 66, 9, 57, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        [63, 39, 54, 12, 73, 61, 18, 1, 6, 62, 71, 19, 68, 69, 3, 44],
+        [0, 0, 0, 69, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+        [0, 0, 57, 0, 55, 55, 55, 0, 22, 22, 67, 22, 36, 25, 24, 37],
+        [0, 5, 68, 0, 29, 15, 73, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+        [0, 64, 34, 17, 23, 52, 53, 48, 46, 8, 35, 42, 0, 28, 13, 31],
+        [11, 58, 0, 6, 0, 0, 30, 0, 0, 0, 0, 0, 0, 0, 32, 0],
+        [16, 26, 22, 38, 39, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+        [16, 50, 2, 21, 66, 9, 57, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+        [16, 70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+        [63, 41, 54, 12, 75, 61, 18, 1, 7, 62, 74, 20, 71, 72, 4, 45],
     ];
-    static BITSET_CANONICAL: [u64; 55] = [
+    const BITSET_CANONICAL: &'static [u64; 55] = &[
         0b0000000000000000000000000000000000000000000000000000000000000000,
         0b1111111111111111110000000000000000000000000011111111111111111111,
         0b1010101010101010101010101010101010101010101010101010100000000010,
-        0b1111111111111111111111000000000000000000000000001111110111111111,
-        0b0000111111111111111111111111111111111111000000000000000000000000,
-        0b1000000000000010000000000000000000000000000000000000000000000000,
-        0b0000111111111111111111111111110000000000000000000000000011111111,
         0b0000000000000111111111111111111111111111111111111111111111111111,
+        0b1111111111111111111111000000000000000000000000001111110111111111,
+        0b1000000000000010000000000000000000000000000000000000000000000000,
+        0b0000111111111111111111111111111111111111000000000000000000000000,
+        0b0000111111111111111111111111110000000000000000000000000011111111,
         0b1111111111111111111111111111111111111111111111111010101010000101,
         0b1111111111111111111111111111111100000000000000000000000000000000,
         0b1111111111111111111111111111110000000000000000000000000000000000,
         0b1111111111111111111111110000000000000000000000000000000000000000,
         0b1111111111111111111111000000000000000000000000001111111111101111,
         0b1111111111111111111100000000000000000000000000010000000000000000,
-        0b1111111111111111000000011111111111110111111111111111111111111111,
+        0b1111111111111111000000111111111111110111111111111111111111111111,
         0b1111111111111111000000000000000000000000000000000100001111000000,
         0b1111111111111111000000000000000000000000000000000000000000000000,
         0b1111111101111111111111111111111110000000000000000000000000000000,
         0b1111110000000000000000000000000011111111111111111111111111000000,
+        0b1111011111111111111111111111111111111111111111110000000000000000,
         0b1111000000000000000000000000001111110111111111111111111111111100,
         0b1010101010101010101010101010101010101010101010101101010101010100,
         0b1010101010101010101010101010101010101010101010101010101010101010,
@@ -379,16 +389,16 @@ pub mod lowercase {
         0b0001101111111011111111111111101111111111100000000000000000000000,
         0b0001100100101111101010101010101010101010111000110111111111111111,
         0b0000011111111101111111111111111111111111111111111111111110111001,
-        0b0000011101000000000000000000000000000010101010100000010100001010,
+        0b0000011101011100000000000000000000000010101010100000010100001010,
         0b0000010000100000000001000000000000000000000000000000000000000000,
         0b0000000111111111111111111111111111111111111011111111111111111111,
         0b0000000011111111000000001111111100000000001111110000000011111111,
         0b0000000011011100000000001111111100000000110011110000000011011100,
         0b0000000000001000010100000001101010101010101010101010101010101010,
         0b0000000000000000001000001011111111111111111111111111111111111111,
+        0b0000000000000000000001111110000001111111111111111111101111111111,
         0b0000000000000000000000001111111111111111110111111100000000000000,
         0b0000000000000000000000000001111100000000000000000000000000000011,
-        0b0000000000000000000000000000000001111111111111111111101111111111,
         0b0000000000000000000000000000000000111010101010101010101010101010,
         0b0000000000000000000000000000000000000000111110000000000001111111,
         0b0000000000000000000000000000000000000000000000000000101111110111,
@@ -400,16 +410,16 @@ pub mod lowercase {
         0b1010101010101011101010101010100000000000000000000000000000000000,
         0b1101010010101010101010101010101010101010101010101010101101010101,
         0b1110011001010001001011010010101001001110001001000011000100101001,
-        0b1110011111111111111111111111111111111111111111110000000000000000,
         0b1110101111000000000000000000000000001111111111111111111111111100,
     ];
-    static BITSET_MAPPING: [(u8, u8); 20] = [
+    const BITSET_MAPPING: &'static [(u8, u8); 21] = &[
         (0, 64), (1, 188), (1, 183), (1, 176), (1, 109), (1, 124), (1, 126), (1, 66), (1, 70),
-        (1, 77), (2, 146), (2, 144), (2, 83), (3, 12), (3, 6), (4, 156), (4, 78), (5, 187),
-        (6, 132), (7, 93),
+        (1, 77), (2, 146), (2, 144), (2, 83), (3, 93), (3, 147), (3, 133), (4, 12), (4, 6),
+        (5, 187), (6, 78), (7, 132),
     ];
 
-    pub fn lookup(c: char) -> bool {
+    #[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]
+    pub const fn lookup(c: char) -> bool {
         super::bitset_search(
             c as u32,
             &BITSET_CHUNKS_MAP,
@@ -422,14 +432,14 @@ pub mod lowercase {
 
 #[rustfmt::skip]
 pub mod n {
-    static SHORT_OFFSET_RUNS: [u32; 38] = [
+    static SHORT_OFFSET_RUNS: [u32; 39] = [
         1632, 18876774, 31461440, 102765417, 111154926, 115349830, 132128880, 165684320, 186656630,
         195046653, 199241735, 203436434, 216049184, 241215536, 249605104, 274792208, 278987015,
         283181793, 295766104, 320933114, 383848032, 392238160, 434181712, 442570976, 455154768,
-        463544256, 476128256, 480340576, 484535936, 501338848, 505534414, 513925440, 518120176,
-        522315975, 526511217, 534900992, 555875312, 561183738,
+        463544144, 476128256, 484534880, 488730240, 505533120, 509728718, 522314048, 526508784,
+        530703600, 534898887, 539094129, 547483904, 568458224, 573766650,
     ];
-    static OFFSETS: [u8; 269] = [
+    static OFFSETS: [u8; 275] = [
         48, 10, 120, 2, 5, 1, 2, 3, 0, 10, 134, 10, 198, 10, 0, 10, 118, 10, 4, 6, 108, 10, 118,
         10, 118, 10, 2, 6, 110, 13, 115, 10, 8, 7, 103, 10, 104, 7, 7, 19, 109, 10, 96, 10, 118, 10,
         70, 20, 0, 10, 70, 10, 0, 20, 0, 3, 239, 10, 6, 10, 22, 10, 0, 10, 128, 11, 165, 10, 6, 10,
@@ -439,9 +449,9 @@ pub mod n {
         29, 1, 8, 1, 134, 5, 202, 10, 0, 8, 25, 7, 39, 9, 75, 5, 22, 6, 160, 2, 2, 16, 2, 46, 64, 9,
         52, 2, 30, 3, 75, 5, 104, 8, 24, 8, 41, 7, 0, 6, 48, 10, 0, 31, 158, 10, 42, 4, 112, 7, 134,
         30, 128, 10, 60, 10, 144, 10, 7, 20, 251, 10, 0, 10, 118, 10, 0, 10, 102, 10, 102, 12, 0,
-        19, 93, 10, 0, 29, 227, 10, 70, 10, 0, 21, 0, 111, 0, 10, 86, 10, 134, 10, 1, 7, 0, 23, 0,
-        20, 108, 25, 0, 50, 0, 10, 0, 10, 0, 9, 128, 10, 0, 59, 1, 3, 1, 4, 76, 45, 1, 15, 0, 13, 0,
-        10, 0,
+        19, 93, 10, 0, 29, 227, 10, 70, 10, 0, 10, 102, 21, 0, 111, 0, 10, 86, 10, 134, 10, 1, 7, 0,
+        23, 0, 20, 12, 20, 108, 25, 0, 50, 0, 10, 0, 10, 0, 10, 0, 9, 128, 10, 0, 59, 1, 3, 1, 4,
+        76, 45, 1, 15, 0, 13, 0, 10, 0,
     ];
     pub fn lookup(c: char) -> bool {
         super::skip_search(
@@ -454,14 +464,14 @@ pub mod n {
 
 #[rustfmt::skip]
 pub mod uppercase {
-    static BITSET_CHUNKS_MAP: [u8; 125] = [
+    const BITSET_CHUNKS_MAP: &'static [u8; 125] = &[
         12, 15, 6, 6, 0, 6, 6, 2, 4, 11, 6, 16, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
         6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 8, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
         6, 6, 6, 5, 6, 14, 6, 10, 6, 6, 1, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
         6, 7, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 13, 6, 6,
         6, 6, 9, 6, 3,
     ];
-    static BITSET_INDEX_CHUNKS: [[u8; 16]; 17] = [
+    const BITSET_INDEX_CHUNKS: &'static [[u8; 16]; 17] = &[
         [43, 43, 5, 34, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 5, 1],
         [43, 43, 5, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43],
         [43, 43, 39, 43, 43, 43, 43, 43, 17, 17, 62, 17, 42, 29, 24, 23],
@@ -480,7 +490,7 @@ pub mod uppercase {
         [57, 19, 2, 18, 10, 47, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43],
         [57, 37, 17, 27, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43],
     ];
-    static BITSET_CANONICAL: [u64; 43] = [
+    const BITSET_CANONICAL: &'static [u64; 43] = &[
         0b0000011111111111111111111111111000000000000000000000000000000000,
         0b0000000000111111111111111111111111111111111111111111111111111111,
         0b0101010101010101010101010101010101010101010101010101010000000001,
@@ -525,13 +535,14 @@ pub mod uppercase {
         0b1111011111111111000000000000000000000000000000000000000000000000,
         0b1111111100000000111111110000000000111111000000001111111100000000,
     ];
-    static BITSET_MAPPING: [(u8, u8); 25] = [
+    const BITSET_MAPPING: &'static [(u8, u8); 25] = &[
         (0, 187), (0, 177), (0, 171), (0, 167), (0, 164), (0, 32), (0, 47), (0, 51), (0, 121),
         (0, 117), (0, 109), (1, 150), (1, 148), (1, 142), (1, 134), (1, 131), (1, 64), (2, 164),
         (2, 146), (2, 20), (3, 146), (3, 140), (3, 134), (4, 178), (4, 171),
     ];
 
-    pub fn lookup(c: char) -> bool {
+    #[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]
+    pub const fn lookup(c: char) -> bool {
         super::bitset_search(
             c as u32,
             &BITSET_CHUNKS_MAP,
diff --git a/library/core/tests/any.rs b/library/core/tests/any.rs
index 8ed0c88808fe..9538b8139495 100644
--- a/library/core/tests/any.rs
+++ b/library/core/tests/any.rs
@@ -142,7 +142,7 @@ impl Provider for SomeConcreteType {
         demand
             .provide_ref::<String>(&self.some_string)
             .provide_ref::<str>(&self.some_string)
-            .provide_value::<String>(|| "bye".to_owned());
+            .provide_value_with::<String>(|| "bye".to_owned());
     }
 }
 
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index c315f3a79751..46f603eaebac 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -3,6 +3,7 @@
 #![feature(array_methods)]
 #![feature(array_windows)]
 #![feature(bench_black_box)]
+#![feature(bigint_helper_methods)]
 #![feature(cell_update)]
 #![feature(const_assume)]
 #![feature(const_black_box)]
@@ -73,6 +74,7 @@
 #![feature(iterator_try_reduce)]
 #![feature(const_mut_refs)]
 #![feature(const_pin)]
+#![feature(const_waker)]
 #![feature(never_type)]
 #![feature(unwrap_infallible)]
 #![feature(pointer_byte_offsets)]
diff --git a/library/core/tests/num/int_macros.rs b/library/core/tests/num/int_macros.rs
index 8b84a78e6be0..18c55e43aac8 100644
--- a/library/core/tests/num/int_macros.rs
+++ b/library/core/tests/num/int_macros.rs
@@ -338,6 +338,32 @@ macro_rules! int_module {
                 assert_eq!(MIN.checked_next_multiple_of(-3), None);
                 assert_eq!(MIN.checked_next_multiple_of(-1), Some(MIN));
             }
+
+            #[test]
+            fn test_carrying_add() {
+                assert_eq!($T::MAX.carrying_add(1, false), ($T::MIN, true));
+                assert_eq!($T::MAX.carrying_add(0, true), ($T::MIN, true));
+                assert_eq!($T::MAX.carrying_add(1, true), ($T::MIN + 1, true));
+                assert_eq!($T::MAX.carrying_add(-1, false), ($T::MAX - 1, false));
+                assert_eq!($T::MAX.carrying_add(-1, true), ($T::MAX, false)); // no intermediate overflow
+                assert_eq!($T::MIN.carrying_add(-1, false), ($T::MAX, true));
+                assert_eq!($T::MIN.carrying_add(-1, true), ($T::MIN, false)); // no intermediate overflow
+                assert_eq!((0 as $T).carrying_add($T::MAX, true), ($T::MIN, true));
+                assert_eq!((0 as $T).carrying_add($T::MIN, true), ($T::MIN + 1, false));
+            }
+
+            #[test]
+            fn test_borrowing_sub() {
+                assert_eq!($T::MIN.borrowing_sub(1, false), ($T::MAX, true));
+                assert_eq!($T::MIN.borrowing_sub(0, true), ($T::MAX, true));
+                assert_eq!($T::MIN.borrowing_sub(1, true), ($T::MAX - 1, true));
+                assert_eq!($T::MIN.borrowing_sub(-1, false), ($T::MIN + 1, false));
+                assert_eq!($T::MIN.borrowing_sub(-1, true), ($T::MIN, false)); // no intermediate overflow
+                assert_eq!($T::MAX.borrowing_sub(-1, false), ($T::MIN, true));
+                assert_eq!($T::MAX.borrowing_sub(-1, true), ($T::MAX, false)); // no intermediate overflow
+                assert_eq!((0 as $T).borrowing_sub($T::MIN, false), ($T::MIN, true));
+                assert_eq!((0 as $T).borrowing_sub($T::MIN, true), ($T::MAX, false));
+            }
         }
     };
 }
diff --git a/library/core/tests/num/uint_macros.rs b/library/core/tests/num/uint_macros.rs
index 93ae620c2330..15ae9f2324f6 100644
--- a/library/core/tests/num/uint_macros.rs
+++ b/library/core/tests/num/uint_macros.rs
@@ -230,6 +230,28 @@ macro_rules! uint_module {
                 assert_eq!((1 as $T).checked_next_multiple_of(0), None);
                 assert_eq!(MAX.checked_next_multiple_of(2), None);
             }
+
+            #[test]
+            fn test_carrying_add() {
+                assert_eq!($T::MAX.carrying_add(1, false), (0, true));
+                assert_eq!($T::MAX.carrying_add(0, true), (0, true));
+                assert_eq!($T::MAX.carrying_add(1, true), (1, true));
+
+                assert_eq!($T::MIN.carrying_add($T::MAX, false), ($T::MAX, false));
+                assert_eq!($T::MIN.carrying_add(0, true), (1, false));
+                assert_eq!($T::MIN.carrying_add($T::MAX, true), (0, true));
+            }
+
+            #[test]
+            fn test_borrowing_sub() {
+                assert_eq!($T::MIN.borrowing_sub(1, false), ($T::MAX, true));
+                assert_eq!($T::MIN.borrowing_sub(0, true), ($T::MAX, true));
+                assert_eq!($T::MIN.borrowing_sub(1, true), ($T::MAX - 1, true));
+
+                assert_eq!($T::MAX.borrowing_sub($T::MAX, false), (0, false));
+                assert_eq!($T::MAX.borrowing_sub(0, true), ($T::MAX - 1, false));
+                assert_eq!($T::MAX.borrowing_sub($T::MAX, true), ($T::MAX, true));
+            }
         }
     };
 }
diff --git a/library/core/tests/task.rs b/library/core/tests/task.rs
index d71fef9e5c87..56be30e92824 100644
--- a/library/core/tests/task.rs
+++ b/library/core/tests/task.rs
@@ -1,4 +1,4 @@
-use core::task::Poll;
+use core::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
 
 #[test]
 fn poll_const() {
@@ -12,3 +12,18 @@ fn poll_const() {
     const IS_PENDING: bool = POLL.is_pending();
     assert!(IS_PENDING);
 }
+
+#[test]
+fn waker_const() {
+    const VOID_TABLE: RawWakerVTable = RawWakerVTable::new(|_| VOID_WAKER, |_| {}, |_| {}, |_| {});
+
+    const VOID_WAKER: RawWaker = RawWaker::new(&(), &VOID_TABLE);
+
+    static WAKER: Waker = unsafe { Waker::from_raw(VOID_WAKER) };
+
+    static CONTEXT: Context<'static> = Context::from_waker(&WAKER);
+
+    static WAKER_REF: &'static Waker = CONTEXT.waker();
+
+    WAKER_REF.wake_by_ref();
+}
diff --git a/library/portable-simd/crates/core_simd/src/masks/to_bitmask.rs b/library/portable-simd/crates/core_simd/src/masks/to_bitmask.rs
index 65d3ce9be65e..2235f016c714 100644
--- a/library/portable-simd/crates/core_simd/src/masks/to_bitmask.rs
+++ b/library/portable-simd/crates/core_simd/src/masks/to_bitmask.rs
@@ -70,7 +70,7 @@ impl_integer_intrinsic! {
     impl ToBitMask<BitMask=u64> for Mask<_, 64>
 }
 
-/// Returns the minimum numnber of bytes in a bitmask with `lanes` lanes.
+/// Returns the minimum number of bytes in a bitmask with `lanes` lanes.
 #[cfg(feature = "generic_const_exprs")]
 pub const fn bitmask_len(lanes: usize) -> usize {
     (lanes + 7) / 8
diff --git a/library/portable-simd/crates/std_float/src/lib.rs b/library/portable-simd/crates/std_float/src/lib.rs
index 4bd4d4c05e3b..4ac60b10c92e 100644
--- a/library/portable-simd/crates/std_float/src/lib.rs
+++ b/library/portable-simd/crates/std_float/src/lib.rs
@@ -1,9 +1,5 @@
 #![cfg_attr(feature = "as_crate", no_std)] // We are std!
-#![cfg_attr(
-    feature = "as_crate",
-    feature(platform_intrinsics),
-    feature(portable_simd)
-)]
+#![cfg_attr(feature = "as_crate", feature(platform_intrinsics), feature(portable_simd))]
 #[cfg(not(feature = "as_crate"))]
 use core::simd;
 #[cfg(feature = "as_crate")]
diff --git a/library/proc_macro/src/bridge/client.rs b/library/proc_macro/src/bridge/client.rs
index 1516f084ab8b..4461b21802ad 100644
--- a/library/proc_macro/src/bridge/client.rs
+++ b/library/proc_macro/src/bridge/client.rs
@@ -176,8 +176,6 @@ define_handles! {
     FreeFunctions,
     TokenStream,
     SourceFile,
-    MultiSpan,
-    Diagnostic,
 
     'interned:
     Span,
diff --git a/library/proc_macro/src/bridge/mod.rs b/library/proc_macro/src/bridge/mod.rs
index 5cde966bf173..4c1e196b5ad1 100644
--- a/library/proc_macro/src/bridge/mod.rs
+++ b/library/proc_macro/src/bridge/mod.rs
@@ -57,6 +57,7 @@ macro_rules! with_api {
                 fn track_env_var(var: &str, value: Option<&str>);
                 fn track_path(path: &str);
                 fn literal_from_str(s: &str) -> Result<Literal<$S::Span, $S::Symbol>, ()>;
+                fn emit_diagnostic(diagnostic: Diagnostic<$S::Span>);
             },
             TokenStream {
                 fn drop($self: $S::TokenStream);
@@ -87,22 +88,6 @@ macro_rules! with_api {
                 fn path($self: &$S::SourceFile) -> String;
                 fn is_real($self: &$S::SourceFile) -> bool;
             },
-            MultiSpan {
-                fn drop($self: $S::MultiSpan);
-                fn new() -> $S::MultiSpan;
-                fn push($self: &mut $S::MultiSpan, span: $S::Span);
-            },
-            Diagnostic {
-                fn drop($self: $S::Diagnostic);
-                fn new(level: Level, msg: &str, span: $S::MultiSpan) -> $S::Diagnostic;
-                fn sub(
-                    $self: &mut $S::Diagnostic,
-                    level: Level,
-                    msg: &str,
-                    span: $S::MultiSpan,
-                );
-                fn emit($self: $S::Diagnostic);
-            },
             Span {
                 fn debug($self: $S::Span) -> String;
                 fn source_file($self: $S::Span) -> $S::SourceFile;
@@ -510,6 +495,18 @@ compound_traits!(
     }
 );
 
+#[derive(Clone, Debug)]
+pub struct Diagnostic<Span> {
+    pub level: Level,
+    pub message: String,
+    pub spans: Vec<Span>,
+    pub children: Vec<Diagnostic<Span>>,
+}
+
+compound_traits!(
+    struct Diagnostic<Span> { level, message, spans, children }
+);
+
 /// Globals provided alongside the initial inputs for a macro expansion.
 /// Provides values such as spans which are used frequently to avoid RPC.
 #[derive(Clone)]
diff --git a/library/proc_macro/src/bridge/server.rs b/library/proc_macro/src/bridge/server.rs
index e068ec60b6af..8202c40d6317 100644
--- a/library/proc_macro/src/bridge/server.rs
+++ b/library/proc_macro/src/bridge/server.rs
@@ -2,6 +2,7 @@
 
 use super::*;
 
+use std::cell::Cell;
 use std::marker::PhantomData;
 
 // FIXME(eddyb) generate the definition of `HandleStore` in `server.rs`.
@@ -11,8 +12,6 @@ pub trait Types {
     type FreeFunctions: 'static;
     type TokenStream: 'static + Clone;
     type SourceFile: 'static + Clone;
-    type MultiSpan: 'static;
-    type Diagnostic: 'static;
     type Span: 'static + Copy + Eq + Hash;
     type Symbol: 'static;
 }
@@ -145,6 +144,38 @@ pub trait ExecutionStrategy {
     ) -> Buffer;
 }
 
+thread_local! {
+    /// While running a proc-macro with the same-thread executor, this flag will
+    /// be set, forcing nested proc-macro invocations (e.g. due to
+    /// `TokenStream::expand_expr`) to be run using a cross-thread executor.
+    ///
+    /// This is required as the thread-local state in the proc_macro client does
+    /// not handle being re-entered, and will invalidate all `Symbol`s when
+    /// entering a nested macro.
+    static ALREADY_RUNNING_SAME_THREAD: Cell<bool> = Cell::new(false);
+}
+
+/// Keep `ALREADY_RUNNING_SAME_THREAD` (see also its documentation)
+/// set to `true`, preventing same-thread reentrance.
+struct RunningSameThreadGuard(());
+
+impl RunningSameThreadGuard {
+    fn new() -> Self {
+        let already_running = ALREADY_RUNNING_SAME_THREAD.replace(true);
+        assert!(
+            !already_running,
+            "same-thread nesting (\"reentrance\") of proc macro executions is not supported"
+        );
+        RunningSameThreadGuard(())
+    }
+}
+
+impl Drop for RunningSameThreadGuard {
+    fn drop(&mut self) {
+        ALREADY_RUNNING_SAME_THREAD.set(false);
+    }
+}
+
 pub struct MaybeCrossThread<P> {
     cross_thread: bool,
     marker: PhantomData<P>,
@@ -167,7 +198,7 @@ where
         run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
         force_show_panics: bool,
     ) -> Buffer {
-        if self.cross_thread {
+        if self.cross_thread || ALREADY_RUNNING_SAME_THREAD.get() {
             <CrossThread<P>>::new().run_bridge_and_client(
                 dispatcher,
                 input,
@@ -190,6 +221,8 @@ impl ExecutionStrategy for SameThread {
         run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
         force_show_panics: bool,
     ) -> Buffer {
+        let _guard = RunningSameThreadGuard::new();
+
         let mut dispatch = |buf| dispatcher.dispatch(buf);
 
         run_client(BridgeConfig {
diff --git a/library/proc_macro/src/diagnostic.rs b/library/proc_macro/src/diagnostic.rs
index 6e46dc0367d0..5a209f7c7aa1 100644
--- a/library/proc_macro/src/diagnostic.rs
+++ b/library/proc_macro/src/diagnostic.rs
@@ -161,22 +161,15 @@ impl Diagnostic {
     /// Emit the diagnostic.
     #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
     pub fn emit(self) {
-        fn to_internal(spans: Vec<Span>) -> crate::bridge::client::MultiSpan {
-            let mut multi_span = crate::bridge::client::MultiSpan::new();
-            for span in spans {
-                multi_span.push(span.0);
+        fn to_internal(diag: Diagnostic) -> crate::bridge::Diagnostic<crate::bridge::client::Span> {
+            crate::bridge::Diagnostic {
+                level: diag.level,
+                message: diag.message,
+                spans: diag.spans.into_iter().map(|s| s.0).collect(),
+                children: diag.children.into_iter().map(to_internal).collect(),
             }
-            multi_span
         }
 
-        let mut diag = crate::bridge::client::Diagnostic::new(
-            self.level,
-            &self.message[..],
-            to_internal(self.spans),
-        );
-        for c in self.children {
-            diag.sub(c.level, &c.message[..], to_internal(c.spans));
-        }
-        diag.emit();
+        crate::bridge::client::FreeFunctions::emit_diagnostic(to_internal(self));
     }
 }
diff --git a/library/proc_macro/src/lib.rs b/library/proc_macro/src/lib.rs
index 8e478cd7bc8a..f9c7d3e172cb 100644
--- a/library/proc_macro/src/lib.rs
+++ b/library/proc_macro/src/lib.rs
@@ -533,7 +533,7 @@ impl Span {
         other.resolved_at(*self)
     }
 
-    /// Compares to spans to see if they're equal.
+    /// Compares two spans to see if they're equal.
     #[unstable(feature = "proc_macro_span", issue = "54725")]
     pub fn eq(&self, other: &Span) -> bool {
         self.0 == other.0
@@ -1353,12 +1353,7 @@ impl Literal {
     /// Byte string literal.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn byte_string(bytes: &[u8]) -> Literal {
-        let string = bytes
-            .iter()
-            .cloned()
-            .flat_map(std::ascii::escape_default)
-            .map(Into::<char>::into)
-            .collect::<String>();
+        let string = bytes.escape_ascii().to_string();
         Literal::new(bridge::LitKind::ByteStr, &string, None)
     }
 
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
index 3da9565a86d7..b8c35ecd3493 100644
--- a/library/std/Cargo.toml
+++ b/library/std/Cargo.toml
@@ -11,7 +11,7 @@ crate-type = ["dylib", "rlib"]
 
 [dependencies]
 alloc = { path = "../alloc" }
-cfg-if = { version = "0.1.8", features = ['rustc-dep-of-std'] }
+cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core" }
@@ -42,7 +42,7 @@ dlmalloc = { version = "0.2.3", features = ['rustc-dep-of-std'] }
 fortanix-sgx-abi = { version = "0.5.0", features = ['rustc-dep-of-std'] }
 
 [target.'cfg(target_os = "hermit")'.dependencies]
-hermit-abi = { version = "0.2.0", features = ['rustc-dep-of-std'] }
+hermit-abi = { version = "0.2.6", features = ['rustc-dep-of-std'] }
 
 [target.wasm32-wasi.dependencies]
 wasi = { version = "0.11.0", features = ['rustc-dep-of-std'], default-features = false }
diff --git a/library/std/src/alloc.rs b/library/std/src/alloc.rs
index a05e0db3af71..61c1ff578b2c 100644
--- a/library/std/src/alloc.rs
+++ b/library/std/src/alloc.rs
@@ -68,7 +68,10 @@ pub use alloc_crate::alloc::*;
 /// The default memory allocator provided by the operating system.
 ///
 /// This is based on `malloc` on Unix platforms and `HeapAlloc` on Windows,
-/// plus related functions.
+/// plus related functions. However, it is not valid to mix use of the backing
+/// system allocator with `System`, as this implementation may include extra
+/// work, such as to serve alignment requests greater than the alignment
+/// provided directly by the backing system allocator.
 ///
 /// This type implements the `GlobalAlloc` trait and Rust programs by default
 /// work as if they had this definition:
diff --git a/library/std/src/backtrace.rs b/library/std/src/backtrace.rs
index 354200d4c95e..5cf6ec817892 100644
--- a/library/std/src/backtrace.rs
+++ b/library/std/src/backtrace.rs
@@ -58,7 +58,7 @@
 //! `RUST_LIB_BACKTRACE` or `RUST_BACKTRACE` at runtime might not actually change
 //! how backtraces are captured.
 
-#![stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+#![stable(feature = "backtrace", since = "1.65.0")]
 
 #[cfg(test)]
 mod tests;
@@ -104,7 +104,7 @@ use crate::vec::Vec;
 /// previous point in time. In some instances the `Backtrace` type may
 /// internally be empty due to configuration. For more information see
 /// `Backtrace::capture`.
-#[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "backtrace", since = "1.65.0")]
 #[must_use]
 pub struct Backtrace {
     inner: Inner,
@@ -112,21 +112,21 @@ pub struct Backtrace {
 
 /// The current status of a backtrace, indicating whether it was captured or
 /// whether it is empty for some other reason.
-#[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "backtrace", since = "1.65.0")]
 #[non_exhaustive]
 #[derive(Debug, PartialEq, Eq)]
 pub enum BacktraceStatus {
     /// Capturing a backtrace is not supported, likely because it's not
     /// implemented for the current platform.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
     Unsupported,
     /// Capturing a backtrace has been disabled through either the
     /// `RUST_LIB_BACKTRACE` or `RUST_BACKTRACE` environment variables.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
     Disabled,
     /// A backtrace has been captured and the `Backtrace` should print
     /// reasonable information when rendered.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
     Captured,
 }
 
@@ -173,7 +173,7 @@ enum BytesOrWide {
     Wide(Vec<u16>),
 }
 
-#[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "backtrace", since = "1.65.0")]
 impl fmt::Debug for Backtrace {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         let capture = match &self.inner {
@@ -289,7 +289,7 @@ impl Backtrace {
     ///
     /// To forcibly capture a backtrace regardless of environment variables, use
     /// the `Backtrace::force_capture` function.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
     #[inline(never)] // want to make sure there's a frame here to remove
     pub fn capture() -> Backtrace {
         if !Backtrace::enabled() {
@@ -308,7 +308,7 @@ impl Backtrace {
     /// Note that capturing a backtrace can be an expensive operation on some
     /// platforms, so this should be used with caution in performance-sensitive
     /// parts of code.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
     #[inline(never)] // want to make sure there's a frame here to remove
     pub fn force_capture() -> Backtrace {
         Backtrace::create(Backtrace::force_capture as usize)
@@ -316,8 +316,8 @@ impl Backtrace {
 
     /// Forcibly captures a disabled backtrace, regardless of environment
     /// variable configuration.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
+    #[rustc_const_stable(feature = "backtrace", since = "1.65.0")]
     pub const fn disabled() -> Backtrace {
         Backtrace { inner: Inner::Disabled }
     }
@@ -361,7 +361,7 @@ impl Backtrace {
     /// Returns the status of this backtrace, indicating whether this backtrace
     /// request was unsupported, disabled, or a stack trace was actually
     /// captured.
-    #[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+    #[stable(feature = "backtrace", since = "1.65.0")]
     #[must_use]
     pub fn status(&self) -> BacktraceStatus {
         match self.inner {
@@ -381,7 +381,7 @@ impl<'a> Backtrace {
     }
 }
 
-#[stable(feature = "backtrace", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "backtrace", since = "1.65.0")]
 impl fmt::Display for Backtrace {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         let capture = match &self.inner {
diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index 9845d1faf9aa..d2db4bb7a46f 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -9,7 +9,6 @@ use crate::borrow::Borrow;
 use crate::cell::Cell;
 use crate::collections::TryReserveError;
 use crate::collections::TryReserveErrorKind;
-#[cfg(not(bootstrap))]
 use crate::error::Error;
 use crate::fmt::{self, Debug};
 #[allow(deprecated)]
@@ -2160,7 +2159,6 @@ impl<'a, K: Debug, V: Debug> fmt::Display for OccupiedError<'a, K, V> {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[unstable(feature = "map_try_insert", issue = "82766")]
 impl<'a, K: fmt::Debug, V: fmt::Debug> Error for OccupiedError<'a, K, V> {
     #[allow(deprecated)]
diff --git a/library/std/src/collections/hash/set.rs b/library/std/src/collections/hash/set.rs
index abff82788a38..5b6a415fadc1 100644
--- a/library/std/src/collections/hash/set.rs
+++ b/library/std/src/collections/hash/set.rs
@@ -239,7 +239,7 @@ impl<T, S> HashSet<T, S> {
     ///
     /// If the returned iterator is dropped before being fully consumed, it
     /// drops the remaining elements. The returned iterator keeps a mutable
-    /// borrow on the vector to optimize its implementation.
+    /// borrow on the set to optimize its implementation.
     ///
     /// # Examples
     ///
diff --git a/library/std/src/error.rs b/library/std/src/error.rs
index e45059595362..05f8fd8de327 100644
--- a/library/std/src/error.rs
+++ b/library/std/src/error.rs
@@ -4,242 +4,12 @@
 #[cfg(test)]
 mod tests;
 
-#[cfg(bootstrap)]
-use core::array;
-#[cfg(bootstrap)]
-use core::convert::Infallible;
-
-#[cfg(bootstrap)]
-use crate::alloc::{AllocError, LayoutError};
-#[cfg(bootstrap)]
-use crate::any::Demand;
-#[cfg(bootstrap)]
-use crate::any::{Provider, TypeId};
 use crate::backtrace::Backtrace;
-#[cfg(bootstrap)]
-use crate::borrow::Cow;
-#[cfg(bootstrap)]
-use crate::cell;
-#[cfg(bootstrap)]
-use crate::char;
-#[cfg(bootstrap)]
-use crate::fmt::Debug;
-#[cfg(bootstrap)]
-use crate::fmt::Display;
 use crate::fmt::{self, Write};
-#[cfg(bootstrap)]
-use crate::io;
-#[cfg(bootstrap)]
-use crate::mem::transmute;
-#[cfg(bootstrap)]
-use crate::num;
-#[cfg(bootstrap)]
-use crate::str;
-#[cfg(bootstrap)]
-use crate::string;
-#[cfg(bootstrap)]
-use crate::sync::Arc;
-#[cfg(bootstrap)]
-use crate::time;
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::error::Error;
 
-/// `Error` is a trait representing the basic expectations for error values,
-/// i.e., values of type `E` in [`Result<T, E>`].
-///
-/// Errors must describe themselves through the [`Display`] and [`Debug`]
-/// traits. Error messages are typically concise lowercase sentences without
-/// trailing punctuation:
-///
-/// ```
-/// let err = "NaN".parse::<u32>().unwrap_err();
-/// assert_eq!(err.to_string(), "invalid digit found in string");
-/// ```
-///
-/// Errors may provide cause information. [`Error::source()`] is generally
-/// used when errors cross "abstraction boundaries". If one module must report
-/// an error that is caused by an error from a lower-level module, it can allow
-/// accessing that error via [`Error::source()`]. This makes it possible for the
-/// high-level module to provide its own errors while also revealing some of the
-/// implementation for debugging.
-#[stable(feature = "rust1", since = "1.0.0")]
-#[cfg_attr(not(test), rustc_diagnostic_item = "Error")]
-#[cfg(bootstrap)]
-pub trait Error: Debug + Display {
-    /// The lower-level source of this error, if any.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::fmt;
-    ///
-    /// #[derive(Debug)]
-    /// struct SuperError {
-    ///     source: SuperErrorSideKick,
-    /// }
-    ///
-    /// impl fmt::Display for SuperError {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "SuperError is here!")
-    ///     }
-    /// }
-    ///
-    /// impl Error for SuperError {
-    ///     fn source(&self) -> Option<&(dyn Error + 'static)> {
-    ///         Some(&self.source)
-    ///     }
-    /// }
-    ///
-    /// #[derive(Debug)]
-    /// struct SuperErrorSideKick;
-    ///
-    /// impl fmt::Display for SuperErrorSideKick {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "SuperErrorSideKick is here!")
-    ///     }
-    /// }
-    ///
-    /// impl Error for SuperErrorSideKick {}
-    ///
-    /// fn get_super_error() -> Result<(), SuperError> {
-    ///     Err(SuperError { source: SuperErrorSideKick })
-    /// }
-    ///
-    /// fn main() {
-    ///     match get_super_error() {
-    ///         Err(e) => {
-    ///             println!("Error: {e}");
-    ///             println!("Caused by: {}", e.source().unwrap());
-    ///         }
-    ///         _ => println!("No error"),
-    ///     }
-    /// }
-    /// ```
-    #[stable(feature = "error_source", since = "1.30.0")]
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        None
-    }
-
-    /// Gets the `TypeId` of `self`.
-    #[doc(hidden)]
-    #[unstable(
-        feature = "error_type_id",
-        reason = "this is memory-unsafe to override in user code",
-        issue = "60784"
-    )]
-    fn type_id(&self, _: private::Internal) -> TypeId
-    where
-        Self: 'static,
-    {
-        TypeId::of::<Self>()
-    }
-
-    /// ```
-    /// if let Err(e) = "xc".parse::<u32>() {
-    ///     // Print `e` itself, no need for description().
-    ///     eprintln!("Error: {e}");
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    #[deprecated(since = "1.42.0", note = "use the Display impl or to_string()")]
-    fn description(&self) -> &str {
-        "description() is deprecated; use Display"
-    }
-
-    #[stable(feature = "rust1", since = "1.0.0")]
-    #[deprecated(
-        since = "1.33.0",
-        note = "replaced by Error::source, which can support downcasting"
-    )]
-    #[allow(missing_docs)]
-    fn cause(&self) -> Option<&dyn Error> {
-        self.source()
-    }
-
-    /// Provides type based access to context intended for error reports.
-    ///
-    /// Used in conjunction with [`Demand::provide_value`] and [`Demand::provide_ref`] to extract
-    /// references to member variables from `dyn Error` trait objects.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// #![feature(provide_any)]
-    /// #![feature(error_generic_member_access)]
-    /// use core::fmt;
-    /// use core::any::Demand;
-    ///
-    /// #[derive(Debug)]
-    /// struct MyBacktrace {
-    ///     // ...
-    /// }
-    ///
-    /// impl MyBacktrace {
-    ///     fn new() -> MyBacktrace {
-    ///         // ...
-    ///         # MyBacktrace {}
-    ///     }
-    /// }
-    ///
-    /// #[derive(Debug)]
-    /// struct SourceError {
-    ///     // ...
-    /// }
-    ///
-    /// impl fmt::Display for SourceError {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "Example Source Error")
-    ///     }
-    /// }
-    ///
-    /// impl std::error::Error for SourceError {}
-    ///
-    /// #[derive(Debug)]
-    /// struct Error {
-    ///     source: SourceError,
-    ///     backtrace: MyBacktrace,
-    /// }
-    ///
-    /// impl fmt::Display for Error {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "Example Error")
-    ///     }
-    /// }
-    ///
-    /// impl std::error::Error for Error {
-    ///     fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
-    ///         demand
-    ///             .provide_ref::<MyBacktrace>(&self.backtrace)
-    ///             .provide_ref::<dyn std::error::Error + 'static>(&self.source);
-    ///     }
-    /// }
-    ///
-    /// fn main() {
-    ///     let backtrace = MyBacktrace::new();
-    ///     let source = SourceError {};
-    ///     let error = Error { source, backtrace };
-    ///     let dyn_error = &error as &dyn std::error::Error;
-    ///     let backtrace_ref = dyn_error.request_ref::<MyBacktrace>().unwrap();
-    ///
-    ///     assert!(core::ptr::eq(&error.backtrace, backtrace_ref));
-    /// }
-    /// ```
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    #[allow(unused_variables)]
-    fn provide<'a>(&'a self, demand: &mut Demand<'a>) {}
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "error_generic_member_access", issue = "99301")]
-impl<'b> Provider for dyn Error + 'b {
-    fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
-        self.provide(demand)
-    }
-}
-
 mod private {
     // This is a hack to prevent `type_id` from being overridden by `Error`
     // implementations, since that can enable unsound downcasting.
@@ -248,799 +18,6 @@ mod private {
     pub struct Internal;
 }
 
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
-    /// Converts a type of [`Error`] into a box of dyn [`Error`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::fmt;
-    /// use std::mem;
-    ///
-    /// #[derive(Debug)]
-    /// struct AnError;
-    ///
-    /// impl fmt::Display for AnError {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "An error")
-    ///     }
-    /// }
-    ///
-    /// impl Error for AnError {}
-    ///
-    /// let an_error = AnError;
-    /// assert!(0 == mem::size_of_val(&an_error));
-    /// let a_boxed_error = Box::<dyn Error>::from(an_error);
-    /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    fn from(err: E) -> Box<dyn Error + 'a> {
-        Box::new(err)
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> {
-    /// Converts a type of [`Error`] + [`Send`] + [`Sync`] into a box of
-    /// dyn [`Error`] + [`Send`] + [`Sync`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::fmt;
-    /// use std::mem;
-    ///
-    /// #[derive(Debug)]
-    /// struct AnError;
-    ///
-    /// impl fmt::Display for AnError {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "An error")
-    ///     }
-    /// }
-    ///
-    /// impl Error for AnError {}
-    ///
-    /// unsafe impl Send for AnError {}
-    ///
-    /// unsafe impl Sync for AnError {}
-    ///
-    /// let an_error = AnError;
-    /// assert!(0 == mem::size_of_val(&an_error));
-    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
-    /// assert!(
-    ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    fn from(err: E) -> Box<dyn Error + Send + Sync + 'a> {
-        Box::new(err)
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl From<String> for Box<dyn Error + Send + Sync> {
-    /// Converts a [`String`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::mem;
-    ///
-    /// let a_string_error = "a string error".to_string();
-    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
-    /// assert!(
-    ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    #[inline]
-    fn from(err: String) -> Box<dyn Error + Send + Sync> {
-        struct StringError(String);
-
-        impl Error for StringError {
-            #[allow(deprecated)]
-            fn description(&self) -> &str {
-                &self.0
-            }
-        }
-
-        impl Display for StringError {
-            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                Display::fmt(&self.0, f)
-            }
-        }
-
-        // Purposefully skip printing "StringError(..)"
-        impl Debug for StringError {
-            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                Debug::fmt(&self.0, f)
-            }
-        }
-
-        Box::new(StringError(err))
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "string_box_error", since = "1.6.0")]
-impl From<String> for Box<dyn Error> {
-    /// Converts a [`String`] into a box of dyn [`Error`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::mem;
-    ///
-    /// let a_string_error = "a string error".to_string();
-    /// let a_boxed_error = Box::<dyn Error>::from(a_string_error);
-    /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    fn from(str_err: String) -> Box<dyn Error> {
-        let err1: Box<dyn Error + Send + Sync> = From::from(str_err);
-        let err2: Box<dyn Error> = err1;
-        err2
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
-    /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
-    ///
-    /// [`str`]: prim@str
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::mem;
-    ///
-    /// let a_str_error = "a str error";
-    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
-    /// assert!(
-    ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    #[inline]
-    fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a> {
-        From::from(String::from(err))
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "string_box_error", since = "1.6.0")]
-impl From<&str> for Box<dyn Error> {
-    /// Converts a [`str`] into a box of dyn [`Error`].
-    ///
-    /// [`str`]: prim@str
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::mem;
-    ///
-    /// let a_str_error = "a str error";
-    /// let a_boxed_error = Box::<dyn Error>::from(a_str_error);
-    /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    fn from(err: &str) -> Box<dyn Error> {
-        From::from(String::from(err))
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cow_box_error", since = "1.22.0")]
-impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
-    /// Converts a [`Cow`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::mem;
-    /// use std::borrow::Cow;
-    ///
-    /// let a_cow_str_error = Cow::from("a str error");
-    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
-    /// assert!(
-    ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a> {
-        From::from(String::from(err))
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cow_box_error", since = "1.22.0")]
-impl<'a> From<Cow<'a, str>> for Box<dyn Error> {
-    /// Converts a [`Cow`] into a box of dyn [`Error`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::error::Error;
-    /// use std::mem;
-    /// use std::borrow::Cow;
-    ///
-    /// let a_cow_str_error = Cow::from("a str error");
-    /// let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
-    /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
-    /// ```
-    fn from(err: Cow<'a, str>) -> Box<dyn Error> {
-        From::from(String::from(err))
-    }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "never_type", issue = "35121")]
-impl Error for ! {}
-
-#[cfg(bootstrap)]
-#[unstable(
-    feature = "allocator_api",
-    reason = "the precise API and guarantees it provides may be tweaked.",
-    issue = "32838"
-)]
-impl Error for AllocError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "alloc_layout", since = "1.28.0")]
-impl Error for LayoutError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for str::ParseBoolError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "failed to parse bool"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for str::Utf8Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "invalid utf-8: corrupt contents"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for num::ParseIntError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        self.__description()
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_from", since = "1.34.0")]
-impl Error for num::TryFromIntError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        self.__description()
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_from", since = "1.34.0")]
-impl Error for array::TryFromSliceError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        self.__description()
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for num::ParseFloatError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        self.__description()
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for string::FromUtf8Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "invalid utf-8"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for string::FromUtf16Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "invalid utf-16"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "str_parse_error2", since = "1.8.0")]
-impl Error for Infallible {
-    fn description(&self) -> &str {
-        match *self {}
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "decode_utf16", since = "1.9.0")]
-impl Error for char::DecodeUtf16Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "unpaired surrogate found"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "u8_from_char", since = "1.59.0")]
-impl Error for char::TryFromCharError {}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "map_try_insert", issue = "82766")]
-impl<'a, K: Debug + Ord, V: Debug> Error
-    for crate::collections::btree_map::OccupiedError<'a, K, V>
-{
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "key already exists"
-    }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "map_try_insert", issue = "82766")]
-impl<'a, K: Debug, V: Debug> Error for crate::collections::hash_map::OccupiedError<'a, K, V> {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "key already exists"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "box_error", since = "1.8.0")]
-impl<T: Error> Error for Box<T> {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        Error::description(&**self)
-    }
-
-    #[allow(deprecated)]
-    fn cause(&self) -> Option<&dyn Error> {
-        Error::cause(&**self)
-    }
-
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        Error::source(&**self)
-    }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "thin_box", issue = "92791")]
-impl<T: ?Sized + crate::error::Error> crate::error::Error for crate::boxed::ThinBox<T> {
-    fn source(&self) -> Option<&(dyn crate::error::Error + 'static)> {
-        use core::ops::Deref;
-        self.deref().source()
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "error_by_ref", since = "1.51.0")]
-impl<'a, T: Error + ?Sized> Error for &'a T {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        Error::description(&**self)
-    }
-
-    #[allow(deprecated)]
-    fn cause(&self) -> Option<&dyn Error> {
-        Error::cause(&**self)
-    }
-
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        Error::source(&**self)
-    }
-
-    fn provide<'b>(&'b self, demand: &mut Demand<'b>) {
-        Error::provide(&**self, demand);
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "arc_error", since = "1.52.0")]
-impl<T: Error + ?Sized> Error for Arc<T> {
-    #[allow(deprecated, deprecated_in_future)]
-    fn description(&self) -> &str {
-        Error::description(&**self)
-    }
-
-    #[allow(deprecated)]
-    fn cause(&self) -> Option<&dyn Error> {
-        Error::cause(&**self)
-    }
-
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        Error::source(&**self)
-    }
-
-    fn provide<'a>(&'a self, demand: &mut Demand<'a>) {
-        Error::provide(&**self, demand);
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "fmt_error", since = "1.11.0")]
-impl Error for fmt::Error {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "an error occurred when formatting an argument"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_borrow", since = "1.13.0")]
-impl Error for cell::BorrowError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "already mutably borrowed"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_borrow", since = "1.13.0")]
-impl Error for cell::BorrowMutError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "already borrowed"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_from", since = "1.34.0")]
-impl Error for char::CharTryFromError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "converted integer out of range for `char`"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "char_from_str", since = "1.20.0")]
-impl Error for char::ParseCharError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        self.__description()
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "try_reserve", since = "1.57.0")]
-impl Error for alloc::collections::TryReserveError {}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "duration_checked_float", issue = "83400")]
-impl Error for time::FromFloatSecsError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Error for alloc::ffi::NulError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "nul byte found in data"
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl From<alloc::ffi::NulError> for io::Error {
-    /// Converts a [`alloc::ffi::NulError`] into a [`io::Error`].
-    fn from(_: alloc::ffi::NulError) -> io::Error {
-        io::const_io_error!(io::ErrorKind::InvalidInput, "data provided contains a nul byte")
-    }
-}
-
-#[cfg(bootstrap)]
-#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")]
-impl Error for core::ffi::FromBytesWithNulError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        self.__description()
-    }
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")]
-impl Error for core::ffi::FromBytesUntilNulError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
-impl Error for alloc::ffi::FromVecWithNulError {}
-
-#[cfg(bootstrap)]
-#[stable(feature = "cstring_into", since = "1.7.0")]
-impl Error for alloc::ffi::IntoStringError {
-    #[allow(deprecated)]
-    fn description(&self) -> &str {
-        "C string contained non-utf8 bytes"
-    }
-
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        Some(self.__source())
-    }
-}
-
-#[cfg(bootstrap)]
-impl<'a> dyn Error + 'a {
-    /// Request a reference of type `T` as context about this error.
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    pub fn request_ref<T: ?Sized + 'static>(&'a self) -> Option<&'a T> {
-        core::any::request_ref(self)
-    }
-
-    /// Request a value of type `T` as context about this error.
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    pub fn request_value<T: 'static>(&'a self) -> Option<T> {
-        core::any::request_value(self)
-    }
-}
-
-// Copied from `any.rs`.
-#[cfg(bootstrap)]
-impl dyn Error + 'static {
-    /// Returns `true` if the inner type is the same as `T`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn is<T: Error + 'static>(&self) -> bool {
-        // Get `TypeId` of the type this function is instantiated with.
-        let t = TypeId::of::<T>();
-
-        // Get `TypeId` of the type in the trait object (`self`).
-        let concrete = self.type_id(private::Internal);
-
-        // Compare both `TypeId`s on equality.
-        t == concrete
-    }
-
-    /// Returns some reference to the inner value if it is of type `T`, or
-    /// `None` if it isn't.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
-        if self.is::<T>() {
-            unsafe { Some(&*(self as *const dyn Error as *const T)) }
-        } else {
-            None
-        }
-    }
-
-    /// Returns some mutable reference to the inner value if it is of type `T`, or
-    /// `None` if it isn't.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
-        if self.is::<T>() {
-            unsafe { Some(&mut *(self as *mut dyn Error as *mut T)) }
-        } else {
-            None
-        }
-    }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + 'static + Send {
-    /// Forwards to the method defined on the type `dyn Error`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn is<T: Error + 'static>(&self) -> bool {
-        <dyn Error + 'static>::is::<T>(self)
-    }
-
-    /// Forwards to the method defined on the type `dyn Error`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
-        <dyn Error + 'static>::downcast_ref::<T>(self)
-    }
-
-    /// Forwards to the method defined on the type `dyn Error`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
-        <dyn Error + 'static>::downcast_mut::<T>(self)
-    }
-
-    /// Request a reference of type `T` as context about this error.
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    pub fn request_ref<T: ?Sized + 'static>(&self) -> Option<&T> {
-        <dyn Error>::request_ref(self)
-    }
-
-    /// Request a value of type `T` as context about this error.
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    pub fn request_value<T: 'static>(&self) -> Option<T> {
-        <dyn Error>::request_value(self)
-    }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + 'static + Send + Sync {
-    /// Forwards to the method defined on the type `dyn Error`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn is<T: Error + 'static>(&self) -> bool {
-        <dyn Error + 'static>::is::<T>(self)
-    }
-
-    /// Forwards to the method defined on the type `dyn Error`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
-        <dyn Error + 'static>::downcast_ref::<T>(self)
-    }
-
-    /// Forwards to the method defined on the type `dyn Error`.
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    #[inline]
-    pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> {
-        <dyn Error + 'static>::downcast_mut::<T>(self)
-    }
-
-    /// Request a reference of type `T` as context about this error.
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    pub fn request_ref<T: ?Sized + 'static>(&self) -> Option<&T> {
-        <dyn Error>::request_ref(self)
-    }
-
-    /// Request a value of type `T` as context about this error.
-    #[unstable(feature = "error_generic_member_access", issue = "99301")]
-    pub fn request_value<T: 'static>(&self) -> Option<T> {
-        <dyn Error>::request_value(self)
-    }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error {
-    #[inline]
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    /// Attempts to downcast the box to a concrete type.
-    pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error>> {
-        if self.is::<T>() {
-            unsafe {
-                let raw: *mut dyn Error = Box::into_raw(self);
-                Ok(Box::from_raw(raw as *mut T))
-            }
-        } else {
-            Err(self)
-        }
-    }
-
-    /// Returns an iterator starting with the current error and continuing with
-    /// recursively calling [`Error::source`].
-    ///
-    /// If you want to omit the current error and only use its sources,
-    /// use `skip(1)`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(error_iter)]
-    /// use std::error::Error;
-    /// use std::fmt;
-    ///
-    /// #[derive(Debug)]
-    /// struct A;
-    ///
-    /// #[derive(Debug)]
-    /// struct B(Option<Box<dyn Error + 'static>>);
-    ///
-    /// impl fmt::Display for A {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "A")
-    ///     }
-    /// }
-    ///
-    /// impl fmt::Display for B {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "B")
-    ///     }
-    /// }
-    ///
-    /// impl Error for A {}
-    ///
-    /// impl Error for B {
-    ///     fn source(&self) -> Option<&(dyn Error + 'static)> {
-    ///         self.0.as_ref().map(|e| e.as_ref())
-    ///     }
-    /// }
-    ///
-    /// let b = B(Some(Box::new(A)));
-    ///
-    /// // let err : Box<Error> = b.into(); // or
-    /// let err = &b as &(dyn Error);
-    ///
-    /// let mut iter = err.sources();
-    ///
-    /// assert_eq!("B".to_string(), iter.next().unwrap().to_string());
-    /// assert_eq!("A".to_string(), iter.next().unwrap().to_string());
-    /// assert!(iter.next().is_none());
-    /// assert!(iter.next().is_none());
-    /// ```
-    #[unstable(feature = "error_iter", issue = "58520")]
-    #[inline]
-    pub fn sources(&self) -> Sources<'_> {
-        // You may think this method would be better in the Error trait, and you'd be right.
-        // Unfortunately that doesn't work, not because of the object safety rules but because we
-        // save a reference to self in Sources below as a trait object. If this method was
-        // declared in Error, then self would have the type &T where T is some concrete type which
-        // implements Error. We would need to coerce self to have type &dyn Error, but that requires
-        // that Self has a known size (i.e., Self: Sized). We can't put that bound on Error
-        // since that would forbid Error trait objects, and we can't put that bound on the method
-        // because that means the method can't be called on trait objects (we'd also need the
-        // 'static bound, but that isn't allowed because methods with bounds on Self other than
-        // Sized are not object-safe). Requiring an Unsize bound is not backwards compatible.
-
-        Sources { current: Some(self) }
-    }
-}
-
-/// An iterator over an [`Error`] and its sources.
-///
-/// If you want to omit the initial error and only process
-/// its sources, use `skip(1)`.
-#[unstable(feature = "error_iter", issue = "58520")]
-#[derive(Clone, Debug)]
-#[cfg(bootstrap)]
-pub struct Sources<'a> {
-    current: Option<&'a (dyn Error + 'static)>,
-}
-
-#[cfg(bootstrap)]
-#[unstable(feature = "error_iter", issue = "58520")]
-impl<'a> Iterator for Sources<'a> {
-    type Item = &'a (dyn Error + 'static);
-
-    fn next(&mut self) -> Option<Self::Item> {
-        let current = self.current;
-        self.current = self.current.and_then(Error::source);
-        current
-    }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + Send {
-    #[inline]
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    /// Attempts to downcast the box to a concrete type.
-    pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error + Send>> {
-        let err: Box<dyn Error> = self;
-        <dyn Error>::downcast(err).map_err(|s| unsafe {
-            // Reapply the `Send` marker.
-            transmute::<Box<dyn Error>, Box<dyn Error + Send>>(s)
-        })
-    }
-}
-
-#[cfg(bootstrap)]
-impl dyn Error + Send + Sync {
-    #[inline]
-    #[stable(feature = "error_downcast", since = "1.3.0")]
-    /// Attempts to downcast the box to a concrete type.
-    pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
-        let err: Box<dyn Error> = self;
-        <dyn Error>::downcast(err).map_err(|s| unsafe {
-            // Reapply the `Send + Sync` marker.
-            transmute::<Box<dyn Error>, Box<dyn Error + Send + Sync>>(s)
-        })
-    }
-}
-
 /// An error reporter that prints an error and its sources.
 ///
 /// Report also exposes configuration options for formatting the error sources, either entirely on a
diff --git a/library/std/src/fs.rs b/library/std/src/fs.rs
index 28a2c99f7e5e..c6c78dc3939e 100644
--- a/library/std/src/fs.rs
+++ b/library/std/src/fs.rs
@@ -19,7 +19,7 @@ use crate::sys::fs as fs_imp;
 use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
 use crate::time::SystemTime;
 
-/// A reference to an open file on the filesystem.
+/// An object providing access to an open file on the filesystem.
 ///
 /// An instance of a `File` can be read and/or written depending on what options
 /// it was opened with. Files also implement [`Seek`] to alter the logical cursor
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 29b09fcc5274..feb3fb989a7a 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -76,7 +76,6 @@ impl fmt::Debug for Error {
     }
 }
 
-#[cfg(not(bootstrap))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl From<alloc::ffi::NulError> for Error {
     /// Converts a [`alloc::ffi::NulError`] into a [`Error`].
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 01a3873c75ce..eeace2c43c4a 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -1045,7 +1045,7 @@ pub trait Read {
 ///     Ok(())
 /// }
 /// ```
-#[stable(feature = "io_read_to_string", since = "CURRENT_RUSTC_VERSION")]
+#[stable(feature = "io_read_to_string", since = "1.65.0")]
 pub fn read_to_string<R: Read>(mut reader: R) -> Result<String> {
     let mut buf = String::new();
     reader.read_to_string(&mut buf)?;
diff --git a/library/std/src/io/stdio.rs b/library/std/src/io/stdio.rs
index 4d3736f79146..2dc12a18a8a6 100644
--- a/library/std/src/io/stdio.rs
+++ b/library/std/src/io/stdio.rs
@@ -8,7 +8,6 @@ use crate::io::prelude::*;
 use crate::cell::{Cell, RefCell};
 use crate::fmt;
 use crate::io::{self, BufReader, IoSlice, IoSliceMut, LineWriter, Lines};
-use crate::pin::Pin;
 use crate::sync::atomic::{AtomicBool, Ordering};
 use crate::sync::{Arc, Mutex, MutexGuard, OnceLock};
 use crate::sys::stdio;
@@ -526,7 +525,7 @@ pub struct Stdout {
     // FIXME: this should be LineWriter or BufWriter depending on the state of
     //        stdout (tty or not). Note that if this is not line buffered it
     //        should also flush-on-panic or some form of flush-on-abort.
-    inner: Pin<&'static ReentrantMutex<RefCell<LineWriter<StdoutRaw>>>>,
+    inner: &'static ReentrantMutex<RefCell<LineWriter<StdoutRaw>>>,
 }
 
 /// A locked reference to the [`Stdout`] handle.
@@ -603,22 +602,27 @@ static STDOUT: OnceLock<ReentrantMutex<RefCell<LineWriter<StdoutRaw>>>> = OnceLo
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn stdout() -> Stdout {
     Stdout {
-        inner: Pin::static_ref(&STDOUT).get_or_init_pin(
-            || unsafe { ReentrantMutex::new(RefCell::new(LineWriter::new(stdout_raw()))) },
-            |mutex| unsafe { mutex.init() },
-        ),
+        inner: STDOUT
+            .get_or_init(|| ReentrantMutex::new(RefCell::new(LineWriter::new(stdout_raw())))),
     }
 }
 
+// Flush the data and disable buffering during shutdown
+// by replacing the line writer by one with zero
+// buffering capacity.
 pub fn cleanup() {
-    if let Some(instance) = STDOUT.get() {
-        // Flush the data and disable buffering during shutdown
-        // by replacing the line writer by one with zero
-        // buffering capacity.
+    let mut initialized = false;
+    let stdout = STDOUT.get_or_init(|| {
+        initialized = true;
+        ReentrantMutex::new(RefCell::new(LineWriter::with_capacity(0, stdout_raw())))
+    });
+
+    if !initialized {
+        // The buffer was previously initialized, overwrite it here.
         // We use try_lock() instead of lock(), because someone
         // might have leaked a StdoutLock, which would
         // otherwise cause a deadlock here.
-        if let Some(lock) = Pin::static_ref(instance).try_lock() {
+        if let Some(lock) = stdout.try_lock() {
             *lock.borrow_mut() = LineWriter::with_capacity(0, stdout_raw());
         }
     }
@@ -761,7 +765,7 @@ impl fmt::Debug for StdoutLock<'_> {
 /// standard library or via raw Windows API calls, will fail.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Stderr {
-    inner: Pin<&'static ReentrantMutex<RefCell<StderrRaw>>>,
+    inner: &'static ReentrantMutex<RefCell<StderrRaw>>,
 }
 
 /// A locked reference to the [`Stderr`] handle.
@@ -834,16 +838,12 @@ pub struct StderrLock<'a> {
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn stderr() -> Stderr {
     // Note that unlike `stdout()` we don't use `at_exit` here to register a
-    // destructor. Stderr is not buffered , so there's no need to run a
+    // destructor. Stderr is not buffered, so there's no need to run a
     // destructor for flushing the buffer
-    static INSTANCE: OnceLock<ReentrantMutex<RefCell<StderrRaw>>> = OnceLock::new();
+    static INSTANCE: ReentrantMutex<RefCell<StderrRaw>> =
+        ReentrantMutex::new(RefCell::new(stderr_raw()));
 
-    Stderr {
-        inner: Pin::static_ref(&INSTANCE).get_or_init_pin(
-            || unsafe { ReentrantMutex::new(RefCell::new(stderr_raw())) },
-            |mutex| unsafe { mutex.init() },
-        ),
-    }
+    Stderr { inner: &INSTANCE }
 }
 
 impl Stderr {
@@ -986,12 +986,15 @@ pub fn set_output_capture(sink: Option<LocalStream>) -> Option<LocalStream> {
 /// otherwise. `label` identifies the stream in a panic message.
 ///
 /// This function is used to print error messages, so it takes extra
-/// care to avoid causing a panic when `local_s` is unusable.
-/// For instance, if the TLS key for the local stream is
-/// already destroyed, or if the local stream is locked by another
-/// thread, it will just fall back to the global stream.
+/// care to avoid causing a panic when `OUTPUT_CAPTURE` is unusable.
+/// For instance, if the TLS key for output capturing is already destroyed, or
+/// if the local stream is in use by another thread, it will just fall back to
+/// the global stream.
 ///
 /// However, if the actual I/O causes an error, this function does panic.
+///
+/// Writing to non-blocking stdout/stderr can cause an error, which will lead
+/// this function to panic.
 fn print_to<T>(args: fmt::Arguments<'_>, global_s: fn() -> T, label: &str)
 where
     T: Write,
diff --git a/library/std/src/keyword_docs.rs b/library/std/src/keyword_docs.rs
index 7157b5af00cf..a4b0522b0502 100644
--- a/library/std/src/keyword_docs.rs
+++ b/library/std/src/keyword_docs.rs
@@ -1921,7 +1921,7 @@ mod type_keyword {}
 /// and [proposal]s exist to use `unsafe {}` blocks inside such functions when
 /// making `unsafe` operations.
 ///
-/// See the [Rustnomicon] and the [Reference] for more informations.
+/// See the [Rustnomicon] and the [Reference] for more information.
 ///
 /// # Examples
 ///
@@ -2113,7 +2113,7 @@ mod use_keyword {}
 /// Add constraints that must be upheld to use an item.
 ///
 /// `where` allows specifying constraints on lifetime and generic parameters.
-/// The [RFC] introducing `where` contains detailed informations about the
+/// The [RFC] introducing `where` contains detailed information about the
 /// keyword.
 ///
 /// # Examples
@@ -2355,7 +2355,7 @@ mod dyn_keyword {}
 /// println!("f = {f} and i = {i}");
 /// ```
 ///
-/// See the [Reference][union] for more informations on `union`s.
+/// See the [Reference][union] for more information on `union`s.
 ///
 /// [`struct`]: keyword.struct.html
 /// [union]: ../reference/items/unions.html
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index f13500de0143..c2b7a4d8648d 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -145,8 +145,8 @@
 //! abstracting over differences in common platforms, most notably Windows and
 //! Unix derivatives.
 //!
-//! Common types of I/O, including [files], [TCP], [UDP], are defined in the
-//! [`io`], [`fs`], and [`net`] modules.
+//! Common types of I/O, including [files], [TCP], and [UDP], are defined in
+//! the [`io`], [`fs`], and [`net`] modules.
 //!
 //! The [`thread`] module contains Rust's threading abstractions. [`sync`]
 //! contains further primitive shared memory types, including [`atomic`] and
@@ -252,10 +252,8 @@
 #![feature(dropck_eyepatch)]
 #![feature(exhaustive_patterns)]
 #![feature(intra_doc_pointers)]
-#![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(lang_items)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(linkage)]
 #![feature(link_cfg)]
 #![feature(min_specialization)]
@@ -282,9 +280,9 @@
 #![feature(cstr_internals)]
 #![feature(duration_checked_float)]
 #![feature(duration_constants)]
-#![cfg_attr(not(bootstrap), feature(error_generic_member_access))]
-#![cfg_attr(not(bootstrap), feature(error_in_core))]
-#![cfg_attr(not(bootstrap), feature(error_iter))]
+#![feature(error_generic_member_access)]
+#![feature(error_in_core)]
+#![feature(error_iter)]
 #![feature(exact_size_is_empty)]
 #![feature(exclusive_wrapper)]
 #![feature(extend_one)]
@@ -315,6 +313,7 @@
 #![feature(strict_provenance)]
 #![feature(maybe_uninit_uninit_array)]
 #![feature(const_maybe_uninit_uninit_array)]
+#![feature(const_waker)]
 //
 // Library features (alloc):
 #![feature(alloc_layout_extra)]
diff --git a/library/std/src/macros.rs b/library/std/src/macros.rs
index a5003c66fcad..6e4ba1404e55 100644
--- a/library/std/src/macros.rs
+++ b/library/std/src/macros.rs
@@ -49,6 +49,9 @@ macro_rules! panic {
 ///
 /// Panics if writing to `io::stdout()` fails.
 ///
+/// Writing to non-blocking stdout can cause an error, which will lead
+/// this macro to panic.
+///
 /// # Examples
 ///
 /// ```
@@ -107,6 +110,9 @@ macro_rules! print {
 ///
 /// Panics if writing to [`io::stdout`] fails.
 ///
+/// Writing to non-blocking stdout can cause an error, which will lead
+/// this macro to panic.
+///
 /// [`io::stdout`]: crate::io::stdout
 ///
 /// # Examples
@@ -147,6 +153,9 @@ macro_rules! println {
 ///
 /// Panics if writing to `io::stderr` fails.
 ///
+/// Writing to non-blocking stdout can cause an error, which will lead
+/// this macro to panic.
+///
 /// # Examples
 ///
 /// ```
@@ -179,6 +188,9 @@ macro_rules! eprint {
 ///
 /// Panics if writing to `io::stderr` fails.
 ///
+/// Writing to non-blocking stdout can cause an error, which will lead
+/// this macro to panic.
+///
 /// # Examples
 ///
 /// ```
diff --git a/library/std/src/net/ip/display_buffer.rs b/library/std/src/net/display_buffer.rs
similarity index 86%
rename from library/std/src/net/ip/display_buffer.rs
rename to library/std/src/net/display_buffer.rs
index bd852d5da8ec..7aadf06e92fc 100644
--- a/library/std/src/net/ip/display_buffer.rs
+++ b/library/std/src/net/display_buffer.rs
@@ -3,12 +3,12 @@ use crate::mem::MaybeUninit;
 use crate::str;
 
 /// Used for slow path in `Display` implementations when alignment is required.
-pub struct IpDisplayBuffer<const SIZE: usize> {
+pub struct DisplayBuffer<const SIZE: usize> {
     buf: [MaybeUninit<u8>; SIZE],
     len: usize,
 }
 
-impl<const SIZE: usize> IpDisplayBuffer<SIZE> {
+impl<const SIZE: usize> DisplayBuffer<SIZE> {
     #[inline]
     pub const fn new() -> Self {
         Self { buf: MaybeUninit::uninit_array(), len: 0 }
@@ -25,7 +25,7 @@ impl<const SIZE: usize> IpDisplayBuffer<SIZE> {
     }
 }
 
-impl<const SIZE: usize> fmt::Write for IpDisplayBuffer<SIZE> {
+impl<const SIZE: usize> fmt::Write for DisplayBuffer<SIZE> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         let bytes = s.as_bytes();
 
diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip_addr.rs
similarity index 99%
rename from library/std/src/net/ip.rs
rename to library/std/src/net/ip_addr.rs
index 6004810655eb..4f14fc28038a 100644
--- a/library/std/src/net/ip.rs
+++ b/library/std/src/net/ip_addr.rs
@@ -8,8 +8,7 @@ use crate::mem::transmute;
 use crate::sys::net::netc as c;
 use crate::sys_common::{FromInner, IntoInner};
 
-mod display_buffer;
-use display_buffer::IpDisplayBuffer;
+use super::display_buffer::DisplayBuffer;
 
 /// An IP address, either IPv4 or IPv6.
 ///
@@ -30,6 +29,7 @@ use display_buffer::IpDisplayBuffer;
 /// assert_eq!(localhost_v4.is_ipv6(), false);
 /// assert_eq!(localhost_v4.is_ipv4(), true);
 /// ```
+#[cfg_attr(not(test), rustc_diagnostic_item = "IpAddr")]
 #[stable(feature = "ip_addr", since = "1.7.0")]
 #[derive(Copy, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
 pub enum IpAddr {
@@ -73,6 +73,7 @@ pub enum IpAddr {
 /// assert!("0xcb.0x0.0x71.0x00".parse::<Ipv4Addr>().is_err()); // all octets are in hex
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Ipv4Addr")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Ipv4Addr {
     octets: [u8; 4],
@@ -155,6 +156,7 @@ pub struct Ipv4Addr {
 /// assert_eq!(localhost.is_loopback(), true);
 /// ```
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Ipv6Addr")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Ipv6Addr {
     octets: [u8; 16],
@@ -997,7 +999,7 @@ impl fmt::Display for Ipv4Addr {
         } else {
             const LONGEST_IPV4_ADDR: &str = "255.255.255.255";
 
-            let mut buf = IpDisplayBuffer::<{ LONGEST_IPV4_ADDR.len() }>::new();
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV4_ADDR.len() }>::new();
             // Buffer is long enough for the longest possible IPv4 address, so this should never fail.
             write!(buf, "{}.{}.{}.{}", octets[0], octets[1], octets[2], octets[3]).unwrap();
 
@@ -1844,7 +1846,7 @@ impl fmt::Display for Ipv6Addr {
         } else {
             const LONGEST_IPV6_ADDR: &str = "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff";
 
-            let mut buf = IpDisplayBuffer::<{ LONGEST_IPV6_ADDR.len() }>::new();
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV6_ADDR.len() }>::new();
             // Buffer is long enough for the longest possible IPv6 address, so this should never fail.
             write!(buf, "{}", self).unwrap();
 
diff --git a/library/std/src/net/ip/tests.rs b/library/std/src/net/ip_addr/tests.rs
similarity index 100%
rename from library/std/src/net/ip/tests.rs
rename to library/std/src/net/ip_addr/tests.rs
diff --git a/library/std/src/net/mod.rs b/library/std/src/net/mod.rs
index 6f9743f3a0eb..01e3db9de51c 100644
--- a/library/std/src/net/mod.rs
+++ b/library/std/src/net/mod.rs
@@ -24,11 +24,11 @@
 use crate::io::{self, ErrorKind};
 
 #[stable(feature = "rust1", since = "1.0.0")]
-pub use self::addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
-#[stable(feature = "rust1", since = "1.0.0")]
-pub use self::ip::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
+pub use self::ip_addr::{IpAddr, Ipv4Addr, Ipv6Addr, Ipv6MulticastScope};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::parser::AddrParseError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::socket_addr::{SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
 #[unstable(feature = "tcplistener_into_incoming", issue = "88339")]
 pub use self::tcp::IntoIncoming;
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -36,9 +36,10 @@ pub use self::tcp::{Incoming, TcpListener, TcpStream};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::udp::UdpSocket;
 
-mod addr;
-mod ip;
+mod display_buffer;
+mod ip_addr;
 mod parser;
+mod socket_addr;
 mod tcp;
 #[cfg(test)]
 pub(crate) mod test;
diff --git a/library/std/src/net/addr.rs b/library/std/src/net/socket_addr.rs
similarity index 94%
rename from library/std/src/net/addr.rs
rename to library/std/src/net/socket_addr.rs
index 53fee952a7a7..33b0dfa03e0e 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/socket_addr.rs
@@ -2,9 +2,9 @@
 mod tests;
 
 use crate::cmp::Ordering;
-use crate::fmt;
+use crate::fmt::{self, Write};
 use crate::hash;
-use crate::io::{self, Write};
+use crate::io;
 use crate::iter;
 use crate::mem;
 use crate::net::{IpAddr, Ipv4Addr, Ipv6Addr};
@@ -15,6 +15,8 @@ use crate::sys_common::net::LookupHost;
 use crate::sys_common::{FromInner, IntoInner};
 use crate::vec;
 
+use super::display_buffer::DisplayBuffer;
+
 /// An internet socket address, either IPv4 or IPv6.
 ///
 /// Internet socket addresses consist of an [IP address], a 16-bit port number, as well
@@ -616,25 +618,18 @@ impl fmt::Debug for SocketAddr {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddrV4 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // Fast path: if there's no alignment stuff, write to the output buffer
-        // directly
+        // If there are no alignment requirements, write the socket address directly to `f`.
+        // Otherwise, write it to a local buffer and then use `f.pad`.
         if f.precision().is_none() && f.width().is_none() {
             write!(f, "{}:{}", self.ip(), self.port())
         } else {
-            const IPV4_SOCKET_BUF_LEN: usize = (3 * 4)  // the segments
-                + 3  // the separators
-                + 1 + 5; // the port
-            let mut buf = [0; IPV4_SOCKET_BUF_LEN];
-            let mut buf_slice = &mut buf[..];
+            const LONGEST_IPV4_SOCKET_ADDR: &str = "255.255.255.255:65536";
 
-            // Unwrap is fine because writing to a sufficiently-sized
-            // buffer is infallible
-            write!(buf_slice, "{}:{}", self.ip(), self.port()).unwrap();
-            let len = IPV4_SOCKET_BUF_LEN - buf_slice.len();
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV4_SOCKET_ADDR.len() }>::new();
+            // Buffer is long enough for the longest possible IPv4 socket address, so this should never fail.
+            write!(buf, "{}:{}", self.ip(), self.port()).unwrap();
 
-            // This unsafe is OK because we know what is being written to the buffer
-            let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
-            f.pad(buf)
+            f.pad(buf.as_str())
         }
     }
 }
@@ -649,35 +644,26 @@ impl fmt::Debug for SocketAddrV4 {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddrV6 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // Fast path: if there's no alignment stuff, write to the output
-        // buffer directly
+        // If there are no alignment requirements, write the socket address directly to `f`.
+        // Otherwise, write it to a local buffer and then use `f.pad`.
         if f.precision().is_none() && f.width().is_none() {
             match self.scope_id() {
                 0 => write!(f, "[{}]:{}", self.ip(), self.port()),
                 scope_id => write!(f, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
             }
         } else {
-            const IPV6_SOCKET_BUF_LEN: usize = (4 * 8)  // The address
-            + 7  // The colon separators
-            + 2  // The brackets
-            + 1 + 10 // The scope id
-            + 1 + 5; // The port
-
-            let mut buf = [0; IPV6_SOCKET_BUF_LEN];
-            let mut buf_slice = &mut buf[..];
+            const LONGEST_IPV6_SOCKET_ADDR: &str =
+                "[ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff%4294967296]:65536";
 
+            let mut buf = DisplayBuffer::<{ LONGEST_IPV6_SOCKET_ADDR.len() }>::new();
             match self.scope_id() {
-                0 => write!(buf_slice, "[{}]:{}", self.ip(), self.port()),
-                scope_id => write!(buf_slice, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
+                0 => write!(buf, "[{}]:{}", self.ip(), self.port()),
+                scope_id => write!(buf, "[{}%{}]:{}", self.ip(), scope_id, self.port()),
             }
-            // Unwrap is fine because writing to a sufficiently-sized
-            // buffer is infallible
+            // Buffer is long enough for the longest possible IPv6 socket address, so this should never fail.
             .unwrap();
-            let len = IPV6_SOCKET_BUF_LEN - buf_slice.len();
 
-            // This unsafe is OK because we know what is being written to the buffer
-            let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
-            f.pad(buf)
+            f.pad(buf.as_str())
         }
     }
 }
diff --git a/library/std/src/net/addr/tests.rs b/library/std/src/net/socket_addr/tests.rs
similarity index 79%
rename from library/std/src/net/addr/tests.rs
rename to library/std/src/net/socket_addr/tests.rs
index 585a17451a0b..15211f81981b 100644
--- a/library/std/src/net/addr/tests.rs
+++ b/library/std/src/net/socket_addr/tests.rs
@@ -51,6 +51,75 @@ fn to_socket_addr_string() {
     // s has been moved into the tsa call
 }
 
+#[test]
+fn ipv4_socket_addr_to_string() {
+    // Shortest possible IPv4 length.
+    assert_eq!(SocketAddrV4::new(Ipv4Addr::new(0, 0, 0, 0), 0).to_string(), "0.0.0.0:0");
+
+    // Longest possible IPv4 length.
+    assert_eq!(
+        SocketAddrV4::new(Ipv4Addr::new(255, 255, 255, 255), u16::MAX).to_string(),
+        "255.255.255.255:65535"
+    );
+
+    // Test padding.
+    assert_eq!(
+        &format!("{:16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
+        "1.1.1.1:53      "
+    );
+    assert_eq!(
+        &format!("{:>16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
+        "      1.1.1.1:53"
+    );
+}
+
+#[test]
+fn ipv6_socket_addr_to_string() {
+    // IPv4-mapped address.
+    assert_eq!(
+        SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc000, 0x280), 8080, 0, 0)
+            .to_string(),
+        "[::ffff:192.0.2.128]:8080"
+    );
+
+    // IPv4-compatible address.
+    assert_eq!(
+        SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0xc000, 0x280), 8080, 0, 0).to_string(),
+        "[::192.0.2.128]:8080"
+    );
+
+    // IPv6 address with no zero segments.
+    assert_eq!(
+        SocketAddrV6::new(Ipv6Addr::new(8, 9, 10, 11, 12, 13, 14, 15), 80, 0, 0).to_string(),
+        "[8:9:a:b:c:d:e:f]:80"
+    );
+
+    // Shortest possible IPv6 length.
+    assert_eq!(SocketAddrV6::new(Ipv6Addr::UNSPECIFIED, 0, 0, 0).to_string(), "[::]:0");
+
+    // Longest possible IPv6 length.
+    assert_eq!(
+        SocketAddrV6::new(
+            Ipv6Addr::new(0x1111, 0x2222, 0x3333, 0x4444, 0x5555, 0x6666, 0x7777, 0x8888),
+            u16::MAX,
+            u32::MAX,
+            u32::MAX,
+        )
+        .to_string(),
+        "[1111:2222:3333:4444:5555:6666:7777:8888%4294967295]:65535"
+    );
+
+    // Test padding.
+    assert_eq!(
+        &format!("{:22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
+        "[1:2:3:4:5:6:7:8]:9   "
+    );
+    assert_eq!(
+        &format!("{:>22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
+        "   [1:2:3:4:5:6:7:8]:9"
+    );
+}
+
 #[test]
 fn bind_udp_socket_bad() {
     // rust-lang/rust#53957: This is a regression test for a parsing problem
diff --git a/library/std/src/os/fd/owned.rs b/library/std/src/os/fd/owned.rs
index a463bc41db7a..71e33fb9ed86 100644
--- a/library/std/src/os/fd/owned.rs
+++ b/library/std/src/os/fd/owned.rs
@@ -104,7 +104,8 @@ impl BorrowedFd<'_> {
         #[cfg(target_os = "espidf")]
         let cmd = libc::F_DUPFD;
 
-        let fd = cvt(unsafe { libc::fcntl(self.as_raw_fd(), cmd, 0) })?;
+        // Avoid using file descriptors below 3 as they are used for stdio
+        let fd = cvt(unsafe { libc::fcntl(self.as_raw_fd(), cmd, 3) })?;
         Ok(unsafe { OwnedFd::from_raw_fd(fd) })
     }
 
diff --git a/library/std/src/os/unix/net/addr.rs b/library/std/src/os/unix/net/addr.rs
index bb313c7597b6..094085e19428 100644
--- a/library/std/src/os/unix/net/addr.rs
+++ b/library/std/src/os/unix/net/addr.rs
@@ -2,7 +2,7 @@ use crate::ffi::OsStr;
 use crate::os::unix::ffi::OsStrExt;
 use crate::path::Path;
 use crate::sys::cvt;
-use crate::{ascii, fmt, io, mem, ptr};
+use crate::{fmt, io, mem, ptr};
 
 // FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here?
 #[cfg(not(unix))]
@@ -64,18 +64,6 @@ enum AddressKind<'a> {
     Abstract(&'a [u8]),
 }
 
-struct AsciiEscaped<'a>(&'a [u8]);
-
-impl<'a> fmt::Display for AsciiEscaped<'a> {
-    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(fmt, "\"")?;
-        for byte in self.0.iter().cloned().flat_map(ascii::escape_default) {
-            write!(fmt, "{}", byte as char)?;
-        }
-        write!(fmt, "\"")
-    }
-}
-
 /// An address associated with a Unix socket.
 ///
 /// # Examples
@@ -343,7 +331,7 @@ impl fmt::Debug for SocketAddr {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.address() {
             AddressKind::Unnamed => write!(fmt, "(unnamed)"),
-            AddressKind::Abstract(name) => write!(fmt, "{} (abstract)", AsciiEscaped(name)),
+            AddressKind::Abstract(name) => write!(fmt, "\"{}\" (abstract)", name.escape_ascii()),
             AddressKind::Pathname(path) => write!(fmt, "{path:?} (pathname)"),
         }
     }
diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs
index 45bc56efb3b9..c4f022de021e 100644
--- a/library/std/src/panic.rs
+++ b/library/std/src/panic.rs
@@ -295,23 +295,22 @@ pub fn get_backtrace_style() -> Option<BacktraceStyle> {
         return Some(style);
     }
 
-    // Setting environment variables for Fuchsia components isn't a standard
-    // or easily supported workflow. For now, display backtraces by default.
-    let format = if cfg!(target_os = "fuchsia") {
-        BacktraceStyle::Full
-    } else {
-        crate::env::var_os("RUST_BACKTRACE")
-            .map(|x| {
-                if &x == "0" {
-                    BacktraceStyle::Off
-                } else if &x == "full" {
-                    BacktraceStyle::Full
-                } else {
-                    BacktraceStyle::Short
-                }
-            })
-            .unwrap_or(BacktraceStyle::Off)
-    };
+    let format = crate::env::var_os("RUST_BACKTRACE")
+        .map(|x| {
+            if &x == "0" {
+                BacktraceStyle::Off
+            } else if &x == "full" {
+                BacktraceStyle::Full
+            } else {
+                BacktraceStyle::Short
+            }
+        })
+        .unwrap_or(if cfg!(target_os = "fuchsia") {
+            // Fuchsia components default to full backtrace.
+            BacktraceStyle::Full
+        } else {
+            BacktraceStyle::Off
+        });
     set_backtrace_style(format);
     Some(format)
 }
diff --git a/library/std/src/panicking.rs b/library/std/src/panicking.rs
index 25c9201f2ed3..4b07b393a2f5 100644
--- a/library/std/src/panicking.rs
+++ b/library/std/src/panicking.rs
@@ -18,9 +18,9 @@ use crate::intrinsics;
 use crate::mem::{self, ManuallyDrop};
 use crate::process;
 use crate::sync::atomic::{AtomicBool, Ordering};
+use crate::sync::{PoisonError, RwLock};
 use crate::sys::stdio::panic_output;
 use crate::sys_common::backtrace;
-use crate::sys_common::rwlock::StaticRwLock;
 use crate::sys_common::thread_info;
 use crate::thread;
 
@@ -71,20 +71,29 @@ extern "C" fn __rust_foreign_exception() -> ! {
     rtabort!("Rust cannot catch foreign exceptions");
 }
 
-#[derive(Copy, Clone)]
 enum Hook {
     Default,
-    Custom(*mut (dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send)),
+    Custom(Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send>),
 }
 
 impl Hook {
-    fn custom(f: impl Fn(&PanicInfo<'_>) + 'static + Sync + Send) -> Self {
-        Self::Custom(Box::into_raw(Box::new(f)))
+    #[inline]
+    fn into_box(self) -> Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send> {
+        match self {
+            Hook::Default => Box::new(default_hook),
+            Hook::Custom(hook) => hook,
+        }
     }
 }
 
-static HOOK_LOCK: StaticRwLock = StaticRwLock::new();
-static mut HOOK: Hook = Hook::Default;
+impl Default for Hook {
+    #[inline]
+    fn default() -> Hook {
+        Hook::Default
+    }
+}
+
+static HOOK: RwLock<Hook> = RwLock::new(Hook::Default);
 
 /// Registers a custom panic hook, replacing any that was previously registered.
 ///
@@ -125,24 +134,13 @@ pub fn set_hook(hook: Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send>) {
         panic!("cannot modify the panic hook from a panicking thread");
     }
 
-    // SAFETY:
-    //
-    // - `HOOK` can only be modified while holding write access to `HOOK_LOCK`.
-    // - The argument of `Box::from_raw` is always a valid pointer that was created using
-    // `Box::into_raw`.
-    unsafe {
-        let guard = HOOK_LOCK.write();
-        let old_hook = HOOK;
-        HOOK = Hook::Custom(Box::into_raw(hook));
-        drop(guard);
-
-        if let Hook::Custom(ptr) = old_hook {
-            #[allow(unused_must_use)]
-            {
-                Box::from_raw(ptr);
-            }
-        }
-    }
+    let new = Hook::Custom(hook);
+    let mut hook = HOOK.write().unwrap_or_else(PoisonError::into_inner);
+    let old = mem::replace(&mut *hook, new);
+    drop(hook);
+    // Only drop the old hook after releasing the lock to avoid deadlocking
+    // if its destructor panics.
+    drop(old);
 }
 
 /// Unregisters the current panic hook, returning it.
@@ -179,22 +177,11 @@ pub fn take_hook() -> Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send> {
         panic!("cannot modify the panic hook from a panicking thread");
     }
 
-    // SAFETY:
-    //
-    // - `HOOK` can only be modified while holding write access to `HOOK_LOCK`.
-    // - The argument of `Box::from_raw` is always a valid pointer that was created using
-    // `Box::into_raw`.
-    unsafe {
-        let guard = HOOK_LOCK.write();
-        let hook = HOOK;
-        HOOK = Hook::Default;
-        drop(guard);
+    let mut hook = HOOK.write().unwrap_or_else(PoisonError::into_inner);
+    let old_hook = mem::take(&mut *hook);
+    drop(hook);
 
-        match hook {
-            Hook::Default => Box::new(default_hook),
-            Hook::Custom(ptr) => Box::from_raw(ptr),
-        }
-    }
+    old_hook.into_box()
 }
 
 /// Atomic combination of [`take_hook`] and [`set_hook`]. Use this to replace the panic handler with
@@ -240,24 +227,9 @@ where
         panic!("cannot modify the panic hook from a panicking thread");
     }
 
-    // SAFETY:
-    //
-    // - `HOOK` can only be modified while holding write access to `HOOK_LOCK`.
-    // - The argument of `Box::from_raw` is always a valid pointer that was created using
-    // `Box::into_raw`.
-    unsafe {
-        let guard = HOOK_LOCK.write();
-        let old_hook = HOOK;
-        HOOK = Hook::Default;
-
-        let prev = match old_hook {
-            Hook::Default => Box::new(default_hook),
-            Hook::Custom(ptr) => Box::from_raw(ptr),
-        };
-
-        HOOK = Hook::custom(move |info| hook_fn(&prev, info));
-        drop(guard);
-    }
+    let mut hook = HOOK.write().unwrap_or_else(PoisonError::into_inner);
+    let prev = mem::take(&mut *hook).into_box();
+    *hook = Hook::Custom(Box::new(move |info| hook_fn(&prev, info)));
 }
 
 fn default_hook(info: &PanicInfo<'_>) {
@@ -328,7 +300,7 @@ pub mod panic_count {
     thread_local! { static LOCAL_PANIC_COUNT: Cell<usize> = const { Cell::new(0) } }
 
     // Sum of panic counts from all threads. The purpose of this is to have
-    // a fast path in `is_zero` (which is used by `panicking`). In any particular
+    // a fast path in `count_is_zero` (which is used by `panicking`). In any particular
     // thread, if that thread currently views `GLOBAL_PANIC_COUNT` as being zero,
     // then `LOCAL_PANIC_COUNT` in that thread is zero. This invariant holds before
     // and after increase and decrease, but not necessarily during their execution.
@@ -397,7 +369,7 @@ pub mod panic_count {
     }
 
     // Slow path is in a separate function to reduce the amount of code
-    // inlined from `is_zero`.
+    // inlined from `count_is_zero`.
     #[inline(never)]
     #[cold]
     fn is_zero_slow_path() -> bool {
@@ -682,27 +654,26 @@ fn rust_panic_with_hook(
         crate::sys::abort_internal();
     }
 
-    unsafe {
-        let mut info = PanicInfo::internal_constructor(message, location, can_unwind);
-        let _guard = HOOK_LOCK.read();
-        match HOOK {
-            // Some platforms (like wasm) know that printing to stderr won't ever actually
-            // print anything, and if that's the case we can skip the default
-            // hook. Since string formatting happens lazily when calling `payload`
-            // methods, this means we avoid formatting the string at all!
-            // (The panic runtime might still call `payload.take_box()` though and trigger
-            // formatting.)
-            Hook::Default if panic_output().is_none() => {}
-            Hook::Default => {
-                info.set_payload(payload.get());
-                default_hook(&info);
-            }
-            Hook::Custom(ptr) => {
-                info.set_payload(payload.get());
-                (*ptr)(&info);
-            }
-        };
-    }
+    let mut info = PanicInfo::internal_constructor(message, location, can_unwind);
+    let hook = HOOK.read().unwrap_or_else(PoisonError::into_inner);
+    match *hook {
+        // Some platforms (like wasm) know that printing to stderr won't ever actually
+        // print anything, and if that's the case we can skip the default
+        // hook. Since string formatting happens lazily when calling `payload`
+        // methods, this means we avoid formatting the string at all!
+        // (The panic runtime might still call `payload.take_box()` though and trigger
+        // formatting.)
+        Hook::Default if panic_output().is_none() => {}
+        Hook::Default => {
+            info.set_payload(payload.get());
+            default_hook(&info);
+        }
+        Hook::Custom(ref hook) => {
+            info.set_payload(payload.get());
+            hook(&info);
+        }
+    };
+    drop(hook);
 
     if panics > 1 || !can_unwind {
         // If a thread panics while it's already unwinding then we
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 5dfeb517a199..4f9dff1ef035 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -2401,7 +2401,7 @@ impl Path {
         self.file_name().map(split_file_at_dot).and_then(|(before, _after)| Some(before))
     }
 
-    /// Extracts the extension of [`self.file_name`], if possible.
+    /// Extracts the extension (without the leading dot) of [`self.file_name`], if possible.
     ///
     /// The extension is:
     ///
diff --git a/library/std/src/primitive_docs.rs b/library/std/src/primitive_docs.rs
index 242f44ade8a2..331714a993c6 100644
--- a/library/std/src/primitive_docs.rs
+++ b/library/std/src/primitive_docs.rs
@@ -611,7 +611,19 @@ mod prim_pointer {}
 ///
 /// Arrays coerce to [slices (`[T]`)][slice], so a slice method may be called on
 /// an array. Indeed, this provides most of the API for working with arrays.
-/// Slices have a dynamic size and do not coerce to arrays.
+///
+/// Slices have a dynamic size and do not coerce to arrays. Instead, use
+/// `slice.try_into().unwrap()` or `<ArrayType>::try_from(slice).unwrap()`.
+///
+/// Array's `try_from(slice)` implementations (and the corresponding `slice.try_into()`
+/// array implementations) succeed if the input slice length is the same as the result
+/// array length. They optimize especially well when the optimizer can easily determine
+/// the slice length, e.g. `<[u8; 4]>::try_from(&slice[4..8]).unwrap()`. Array implements
+/// [TryFrom](crate::convert::TryFrom) returning:
+///
+/// - `[T; N]` copies from the slice's elements
+/// - `&[T; N]` references the original slice's elements
+/// - `&mut [T; N]` references the original slice's elements
 ///
 /// You can move elements out of an array with a [slice pattern]. If you want
 /// one element, see [`mem::replace`].
@@ -640,6 +652,15 @@ mod prim_pointer {}
 /// for x in &array { }
 /// ```
 ///
+/// You can use `<ArrayType>::try_from(slice)` or `slice.try_into()` to get an array from
+/// a slice:
+///
+/// ```
+/// let bytes: [u8; 3] = [1, 0, 2];
+/// assert_eq!(1, u16::from_le_bytes(<[u8; 2]>::try_from(&bytes[0..2]).unwrap()));
+/// assert_eq!(512, u16::from_le_bytes(bytes[1..3].try_into().unwrap()));
+/// ```
+///
 /// You can use a [slice pattern] to move elements out of an array:
 ///
 /// ```
diff --git a/library/std/src/rt.rs b/library/std/src/rt.rs
index 663537a05fa3..b8bcdbece0af 100644
--- a/library/std/src/rt.rs
+++ b/library/std/src/rt.rs
@@ -72,10 +72,29 @@ macro_rules! rtunwrap {
 // Runs before `main`.
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
+//
+// # The `sigpipe` parameter
+//
+// Since 2014, the Rust runtime on Unix has set the `SIGPIPE` handler to
+// `SIG_IGN`. Applications have good reasons to want a different behavior
+// though, so there is a `#[unix_sigpipe = "..."]` attribute on `fn main()` that
+// can be used to select how `SIGPIPE` shall be setup (if changed at all) before
+// `fn main()` is called. See <https://github.com/rust-lang/rust/issues/97889>
+// for more info.
+//
+// The `sigpipe` parameter to this function gets its value via the code that
+// rustc generates to invoke `fn lang_start()`. The reason we have `sigpipe` for
+// all platforms and not only Unix, is because std is not allowed to have `cfg`
+// directives as this high level. See the module docs in
+// `src/tools/tidy/src/pal.rs` for more info. On all other platforms, `sigpipe`
+// has a value, but its value is ignored.
+//
+// Even though it is an `u8`, it only ever has 3 values. These are documented in
+// `compiler/rustc_session/src/config/sigpipe.rs`.
 #[cfg_attr(test, allow(dead_code))]
-unsafe fn init(argc: isize, argv: *const *const u8) {
+unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
     unsafe {
-        sys::init(argc, argv);
+        sys::init(argc, argv, sigpipe);
 
         let main_guard = sys::thread::guard::init();
         // Next, set up the current Thread with the guard information we just
@@ -107,6 +126,7 @@ fn lang_start_internal(
     main: &(dyn Fn() -> i32 + Sync + crate::panic::RefUnwindSafe),
     argc: isize,
     argv: *const *const u8,
+    sigpipe: u8,
 ) -> Result<isize, !> {
     use crate::{mem, panic};
     let rt_abort = move |e| {
@@ -124,7 +144,7 @@ fn lang_start_internal(
     // prevent libstd from accidentally introducing a panic to these functions. Another is from
     // user code from `main` or, more nefariously, as described in e.g. issue #86030.
     // SAFETY: Only called once during runtime initialization.
-    panic::catch_unwind(move || unsafe { init(argc, argv) }).map_err(rt_abort)?;
+    panic::catch_unwind(move || unsafe { init(argc, argv, sigpipe) }).map_err(rt_abort)?;
     let ret_code = panic::catch_unwind(move || panic::catch_unwind(main).unwrap_or(101) as isize)
         .map_err(move |e| {
             mem::forget(e);
@@ -140,11 +160,13 @@ fn lang_start<T: crate::process::Termination + 'static>(
     main: fn() -> T,
     argc: isize,
     argv: *const *const u8,
+    sigpipe: u8,
 ) -> isize {
     let Ok(v) = lang_start_internal(
         &move || crate::sys_common::backtrace::__rust_begin_short_backtrace(main).report().to_i32(),
         argc,
         argv,
+        sigpipe,
     );
     v
 }
diff --git a/library/std/src/sync/mutex.rs b/library/std/src/sync/mutex.rs
index e0d13cd648c6..de851c8fbbed 100644
--- a/library/std/src/sync/mutex.rs
+++ b/library/std/src/sync/mutex.rs
@@ -192,6 +192,7 @@ unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
                       and cause Futures to not implement `Send`"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[clippy::has_significant_drop]
+#[cfg_attr(not(test), rustc_diagnostic_item = "MutexGuard")]
 pub struct MutexGuard<'a, T: ?Sized + 'a> {
     lock: &'a Mutex<T>,
     poison: poison::Guard,
diff --git a/library/std/src/sync/once_lock.rs b/library/std/src/sync/once_lock.rs
index 813516040cdb..37413ec62a71 100644
--- a/library/std/src/sync/once_lock.rs
+++ b/library/std/src/sync/once_lock.rs
@@ -3,7 +3,6 @@ use crate::fmt;
 use crate::marker::PhantomData;
 use crate::mem::MaybeUninit;
 use crate::panic::{RefUnwindSafe, UnwindSafe};
-use crate::pin::Pin;
 use crate::sync::Once;
 
 /// A synchronization primitive which can be written to only once.
@@ -223,60 +222,6 @@ impl<T> OnceLock<T> {
         Ok(unsafe { self.get_unchecked() })
     }
 
-    /// Internal-only API that gets the contents of the cell, initializing it
-    /// in two steps with `f` and `g` if the cell was empty.
-    ///
-    /// `f` is called to construct the value, which is then moved into the cell
-    /// and given as a (pinned) mutable reference to `g` to finish
-    /// initialization.
-    ///
-    /// This allows `g` to inspect an manipulate the value after it has been
-    /// moved into its final place in the cell, but before the cell is
-    /// considered initialized.
-    ///
-    /// # Panics
-    ///
-    /// If `f` or `g` panics, the panic is propagated to the caller, and the
-    /// cell remains uninitialized.
-    ///
-    /// With the current implementation, if `g` panics, the value from `f` will
-    /// not be dropped. This should probably be fixed if this is ever used for
-    /// a type where this matters.
-    ///
-    /// It is an error to reentrantly initialize the cell from `f`. The exact
-    /// outcome is unspecified. Current implementation deadlocks, but this may
-    /// be changed to a panic in the future.
-    pub(crate) fn get_or_init_pin<F, G>(self: Pin<&Self>, f: F, g: G) -> Pin<&T>
-    where
-        F: FnOnce() -> T,
-        G: FnOnce(Pin<&mut T>),
-    {
-        if let Some(value) = self.get_ref().get() {
-            // SAFETY: The inner value was already initialized, and will not be
-            // moved anymore.
-            return unsafe { Pin::new_unchecked(value) };
-        }
-
-        let slot = &self.value;
-
-        // Ignore poisoning from other threads
-        // If another thread panics, then we'll be able to run our closure
-        self.once.call_once_force(|_| {
-            let value = f();
-            // SAFETY: We use the Once (self.once) to guarantee unique access
-            // to the UnsafeCell (slot).
-            let value: &mut T = unsafe { (&mut *slot.get()).write(value) };
-            // SAFETY: The value has been written to its final place in
-            // self.value. We do not to move it anymore, which we promise here
-            // with a Pin<&mut T>.
-            g(unsafe { Pin::new_unchecked(value) });
-        });
-
-        // SAFETY: The inner value has been initialized, and will not be moved
-        // anymore.
-        unsafe { Pin::new_unchecked(self.get_ref().get_unchecked()) }
-    }
-
     /// Consumes the `OnceLock`, returning the wrapped value. Returns
     /// `None` if the cell was empty.
     ///
diff --git a/library/std/src/sync/rwlock.rs b/library/std/src/sync/rwlock.rs
index 6e4a2cfc82af..9ab781561e9b 100644
--- a/library/std/src/sync/rwlock.rs
+++ b/library/std/src/sync/rwlock.rs
@@ -101,6 +101,7 @@ unsafe impl<T: ?Sized + Send + Sync> Sync for RwLock<T> {}
                       and cause Futures to not implement `Send`"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[clippy::has_significant_drop]
+#[cfg_attr(not(test), rustc_diagnostic_item = "RwLockReadGuard")]
 pub struct RwLockReadGuard<'a, T: ?Sized + 'a> {
     // NB: we use a pointer instead of `&'a T` to avoid `noalias` violations, because a
     // `Ref` argument doesn't hold immutability for its whole scope, only until it drops.
@@ -130,6 +131,7 @@ unsafe impl<T: ?Sized + Sync> Sync for RwLockReadGuard<'_, T> {}
                       and cause Future's to not implement `Send`"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[clippy::has_significant_drop]
+#[cfg_attr(not(test), rustc_diagnostic_item = "RwLockWriteGuard")]
 pub struct RwLockWriteGuard<'a, T: ?Sized + 'a> {
     lock: &'a RwLock<T>,
     poison: poison::Guard,
diff --git a/library/std/src/sys/hermit/condvar.rs b/library/std/src/sys/hermit/condvar.rs
deleted file mode 100644
index 22059ca0dbe1..000000000000
--- a/library/std/src/sys/hermit/condvar.rs
+++ /dev/null
@@ -1,90 +0,0 @@
-use crate::ffi::c_void;
-use crate::ptr;
-use crate::sync::atomic::{AtomicUsize, Ordering::SeqCst};
-use crate::sys::hermit::abi;
-use crate::sys::locks::Mutex;
-use crate::sys_common::lazy_box::{LazyBox, LazyInit};
-use crate::time::Duration;
-
-// The implementation is inspired by Andrew D. Birrell's paper
-// "Implementing Condition Variables with Semaphores"
-
-pub struct Condvar {
-    counter: AtomicUsize,
-    sem1: *const c_void,
-    sem2: *const c_void,
-}
-
-pub(crate) type MovableCondvar = LazyBox<Condvar>;
-
-impl LazyInit for Condvar {
-    fn init() -> Box<Self> {
-        Box::new(Self::new())
-    }
-}
-
-unsafe impl Send for Condvar {}
-unsafe impl Sync for Condvar {}
-
-impl Condvar {
-    pub fn new() -> Self {
-        let mut condvar =
-            Self { counter: AtomicUsize::new(0), sem1: ptr::null(), sem2: ptr::null() };
-        unsafe {
-            let _ = abi::sem_init(&mut condvar.sem1, 0);
-            let _ = abi::sem_init(&mut condvar.sem2, 0);
-        }
-        condvar
-    }
-
-    pub unsafe fn notify_one(&self) {
-        if self.counter.load(SeqCst) > 0 {
-            self.counter.fetch_sub(1, SeqCst);
-            abi::sem_post(self.sem1);
-            abi::sem_timedwait(self.sem2, 0);
-        }
-    }
-
-    pub unsafe fn notify_all(&self) {
-        let counter = self.counter.swap(0, SeqCst);
-        for _ in 0..counter {
-            abi::sem_post(self.sem1);
-        }
-        for _ in 0..counter {
-            abi::sem_timedwait(self.sem2, 0);
-        }
-    }
-
-    pub unsafe fn wait(&self, mutex: &Mutex) {
-        self.counter.fetch_add(1, SeqCst);
-        mutex.unlock();
-        abi::sem_timedwait(self.sem1, 0);
-        abi::sem_post(self.sem2);
-        mutex.lock();
-    }
-
-    pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
-        self.counter.fetch_add(1, SeqCst);
-        mutex.unlock();
-        let millis = dur.as_millis().min(u32::MAX as u128) as u32;
-
-        let res = if millis > 0 {
-            abi::sem_timedwait(self.sem1, millis)
-        } else {
-            abi::sem_trywait(self.sem1)
-        };
-
-        abi::sem_post(self.sem2);
-        mutex.lock();
-        res == 0
-    }
-}
-
-impl Drop for Condvar {
-    fn drop(&mut self) {
-        unsafe {
-            let _ = abi::sem_destroy(self.sem1);
-            let _ = abi::sem_destroy(self.sem2);
-        }
-    }
-}
diff --git a/library/std/src/sys/hermit/fs.rs b/library/std/src/sys/hermit/fs.rs
index 1c5efa94bd36..f921839cf529 100644
--- a/library/std/src/sys/hermit/fs.rs
+++ b/library/std/src/sys/hermit/fs.rs
@@ -41,6 +41,9 @@ pub struct OpenOptions {
     mode: i32,
 }
 
+#[derive(Copy, Clone, Debug, Default)]
+pub struct FileTimes {}
+
 pub struct FilePermissions(!);
 
 pub struct FileType(!);
@@ -110,6 +113,11 @@ impl fmt::Debug for FilePermissions {
     }
 }
 
+impl FileTimes {
+    pub fn set_accessed(&mut self, _t: SystemTime) {}
+    pub fn set_modified(&mut self, _t: SystemTime) {}
+}
+
 impl FileType {
     pub fn is_dir(&self) -> bool {
         self.0
@@ -344,6 +352,10 @@ impl File {
     pub fn set_permissions(&self, _perm: FilePermissions) -> io::Result<()> {
         Err(Error::from_raw_os_error(22))
     }
+
+    pub fn set_times(&self, _times: FileTimes) -> io::Result<()> {
+        Err(Error::from_raw_os_error(22))
+    }
 }
 
 impl DirBuilder {
diff --git a/library/std/src/sys/hermit/futex.rs b/library/std/src/sys/hermit/futex.rs
new file mode 100644
index 000000000000..b64c174b06c6
--- /dev/null
+++ b/library/std/src/sys/hermit/futex.rs
@@ -0,0 +1,39 @@
+use super::abi;
+use crate::ptr::null;
+use crate::sync::atomic::AtomicU32;
+use crate::time::Duration;
+
+pub fn futex_wait(futex: &AtomicU32, expected: u32, timeout: Option<Duration>) -> bool {
+    // Calculate the timeout as a relative timespec.
+    //
+    // Overflows are rounded up to an infinite timeout (None).
+    let timespec = timeout.and_then(|dur| {
+        Some(abi::timespec {
+            tv_sec: dur.as_secs().try_into().ok()?,
+            tv_nsec: dur.subsec_nanos().into(),
+        })
+    });
+
+    let r = unsafe {
+        abi::futex_wait(
+            futex.as_mut_ptr(),
+            expected,
+            timespec.as_ref().map_or(null(), |t| t as *const abi::timespec),
+            abi::FUTEX_RELATIVE_TIMEOUT,
+        )
+    };
+
+    r != -abi::errno::ETIMEDOUT
+}
+
+#[inline]
+pub fn futex_wake(futex: &AtomicU32) -> bool {
+    unsafe { abi::futex_wake(futex.as_mut_ptr(), 1) > 0 }
+}
+
+#[inline]
+pub fn futex_wake_all(futex: &AtomicU32) {
+    unsafe {
+        abi::futex_wake(futex.as_mut_ptr(), i32::MAX);
+    }
+}
diff --git a/library/std/src/sys/hermit/mod.rs b/library/std/src/sys/hermit/mod.rs
index 60b7a973cc2c..827d82900eae 100644
--- a/library/std/src/sys/hermit/mod.rs
+++ b/library/std/src/sys/hermit/mod.rs
@@ -25,6 +25,7 @@ pub mod cmath;
 pub mod env;
 pub mod fd;
 pub mod fs;
+pub mod futex;
 #[path = "../unsupported/io.rs"]
 pub mod io;
 pub mod memchr;
@@ -45,14 +46,14 @@ pub mod thread_local_dtor;
 pub mod thread_local_key;
 pub mod time;
 
-mod condvar;
-mod mutex;
-mod rwlock;
-
+#[path = "../unix/locks"]
 pub mod locks {
-    pub use super::condvar::*;
-    pub use super::mutex::*;
-    pub use super::rwlock::*;
+    mod futex_condvar;
+    mod futex_mutex;
+    mod futex_rwlock;
+    pub(crate) use futex_condvar::MovableCondvar;
+    pub(crate) use futex_mutex::{MovableMutex, Mutex};
+    pub(crate) use futex_rwlock::{MovableRwLock, RwLock};
 }
 
 use crate::io::ErrorKind;
@@ -98,7 +99,7 @@ pub extern "C" fn __rust_abort() {
 
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
-pub unsafe fn init(argc: isize, argv: *const *const u8) {
+pub unsafe fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) {
     let _ = net::init();
     args::init(argc, argv);
 }
diff --git a/library/std/src/sys/hermit/mutex.rs b/library/std/src/sys/hermit/mutex.rs
deleted file mode 100644
index eb15a04ffcff..000000000000
--- a/library/std/src/sys/hermit/mutex.rs
+++ /dev/null
@@ -1,216 +0,0 @@
-use crate::cell::UnsafeCell;
-use crate::collections::VecDeque;
-use crate::hint;
-use crate::ops::{Deref, DerefMut, Drop};
-use crate::ptr;
-use crate::sync::atomic::{AtomicUsize, Ordering};
-use crate::sys::hermit::abi;
-
-/// This type provides a lock based on busy waiting to realize mutual exclusion
-///
-/// # Description
-///
-/// This structure behaves a lot like a common mutex. There are some differences:
-///
-/// - By using busy waiting, it can be used outside the runtime.
-/// - It is a so called ticket lock and is completely fair.
-#[cfg_attr(target_arch = "x86_64", repr(align(128)))]
-#[cfg_attr(not(target_arch = "x86_64"), repr(align(64)))]
-struct Spinlock<T: ?Sized> {
-    queue: AtomicUsize,
-    dequeue: AtomicUsize,
-    data: UnsafeCell<T>,
-}
-
-unsafe impl<T: ?Sized + Send> Sync for Spinlock<T> {}
-unsafe impl<T: ?Sized + Send> Send for Spinlock<T> {}
-
-/// A guard to which the protected data can be accessed
-///
-/// When the guard falls out of scope it will release the lock.
-struct SpinlockGuard<'a, T: ?Sized + 'a> {
-    dequeue: &'a AtomicUsize,
-    data: &'a mut T,
-}
-
-impl<T> Spinlock<T> {
-    pub const fn new(user_data: T) -> Spinlock<T> {
-        Spinlock {
-            queue: AtomicUsize::new(0),
-            dequeue: AtomicUsize::new(1),
-            data: UnsafeCell::new(user_data),
-        }
-    }
-
-    #[inline]
-    fn obtain_lock(&self) {
-        let ticket = self.queue.fetch_add(1, Ordering::SeqCst) + 1;
-        let mut counter: u16 = 0;
-        while self.dequeue.load(Ordering::SeqCst) != ticket {
-            counter += 1;
-            if counter < 100 {
-                hint::spin_loop();
-            } else {
-                counter = 0;
-                unsafe {
-                    abi::yield_now();
-                }
-            }
-        }
-    }
-
-    #[inline]
-    pub unsafe fn lock(&self) -> SpinlockGuard<'_, T> {
-        self.obtain_lock();
-        SpinlockGuard { dequeue: &self.dequeue, data: &mut *self.data.get() }
-    }
-}
-
-impl<T: ?Sized + Default> Default for Spinlock<T> {
-    fn default() -> Spinlock<T> {
-        Spinlock::new(Default::default())
-    }
-}
-
-impl<'a, T: ?Sized> Deref for SpinlockGuard<'a, T> {
-    type Target = T;
-    fn deref(&self) -> &T {
-        &*self.data
-    }
-}
-
-impl<'a, T: ?Sized> DerefMut for SpinlockGuard<'a, T> {
-    fn deref_mut(&mut self) -> &mut T {
-        &mut *self.data
-    }
-}
-
-impl<'a, T: ?Sized> Drop for SpinlockGuard<'a, T> {
-    /// The dropping of the SpinlockGuard will release the lock it was created from.
-    fn drop(&mut self) {
-        self.dequeue.fetch_add(1, Ordering::SeqCst);
-    }
-}
-
-/// Realize a priority queue for tasks
-struct PriorityQueue {
-    queues: [Option<VecDeque<abi::Tid>>; abi::NO_PRIORITIES],
-    prio_bitmap: u64,
-}
-
-impl PriorityQueue {
-    pub const fn new() -> PriorityQueue {
-        PriorityQueue {
-            queues: [
-                None, None, None, None, None, None, None, None, None, None, None, None, None, None,
-                None, None, None, None, None, None, None, None, None, None, None, None, None, None,
-                None, None, None,
-            ],
-            prio_bitmap: 0,
-        }
-    }
-
-    /// Add a task id by its priority to the queue
-    pub fn push(&mut self, prio: abi::Priority, id: abi::Tid) {
-        let i: usize = prio.into().into();
-        self.prio_bitmap |= (1 << i) as u64;
-        if let Some(queue) = &mut self.queues[i] {
-            queue.push_back(id);
-        } else {
-            let mut queue = VecDeque::new();
-            queue.push_back(id);
-            self.queues[i] = Some(queue);
-        }
-    }
-
-    fn pop_from_queue(&mut self, queue_index: usize) -> Option<abi::Tid> {
-        if let Some(queue) = &mut self.queues[queue_index] {
-            let id = queue.pop_front();
-
-            if queue.is_empty() {
-                self.prio_bitmap &= !(1 << queue_index as u64);
-            }
-
-            id
-        } else {
-            None
-        }
-    }
-
-    /// Pop the task handle with the highest priority from the queue
-    pub fn pop(&mut self) -> Option<abi::Tid> {
-        for i in 0..abi::NO_PRIORITIES {
-            if self.prio_bitmap & (1 << i) != 0 {
-                return self.pop_from_queue(i);
-            }
-        }
-
-        None
-    }
-}
-
-struct MutexInner {
-    locked: bool,
-    blocked_task: PriorityQueue,
-}
-
-impl MutexInner {
-    pub const fn new() -> MutexInner {
-        MutexInner { locked: false, blocked_task: PriorityQueue::new() }
-    }
-}
-
-pub struct Mutex {
-    inner: Spinlock<MutexInner>,
-}
-
-pub type MovableMutex = Mutex;
-
-unsafe impl Send for Mutex {}
-unsafe impl Sync for Mutex {}
-
-impl Mutex {
-    pub const fn new() -> Mutex {
-        Mutex { inner: Spinlock::new(MutexInner::new()) }
-    }
-
-    #[inline]
-    pub unsafe fn init(&mut self) {}
-
-    #[inline]
-    pub unsafe fn lock(&self) {
-        loop {
-            let mut guard = self.inner.lock();
-            if guard.locked == false {
-                guard.locked = true;
-                return;
-            } else {
-                let prio = abi::get_priority();
-                let id = abi::getpid();
-
-                guard.blocked_task.push(prio, id);
-                abi::block_current_task();
-                drop(guard);
-                abi::yield_now();
-            }
-        }
-    }
-
-    #[inline]
-    pub unsafe fn unlock(&self) {
-        let mut guard = self.inner.lock();
-        guard.locked = false;
-        if let Some(tid) = guard.blocked_task.pop() {
-            abi::wakeup_task(tid);
-        }
-    }
-
-    #[inline]
-    pub unsafe fn try_lock(&self) -> bool {
-        let mut guard = self.inner.lock();
-        if guard.locked == false {
-            guard.locked = true;
-        }
-        guard.locked
-    }
-}
diff --git a/library/std/src/sys/hermit/net.rs b/library/std/src/sys/hermit/net.rs
index 74547617150b..8a13879d8cc8 100644
--- a/library/std/src/sys/hermit/net.rs
+++ b/library/std/src/sys/hermit/net.rs
@@ -487,6 +487,4 @@ pub mod netc {
 
     #[derive(Copy, Clone)]
     pub struct sockaddr {}
-
-    pub type socklen_t = usize;
 }
diff --git a/library/std/src/sys/hermit/rwlock.rs b/library/std/src/sys/hermit/rwlock.rs
deleted file mode 100644
index 9701bab1f660..000000000000
--- a/library/std/src/sys/hermit/rwlock.rs
+++ /dev/null
@@ -1,144 +0,0 @@
-use crate::cell::UnsafeCell;
-use crate::sys::locks::{MovableCondvar, Mutex};
-use crate::sys_common::lazy_box::{LazyBox, LazyInit};
-
-pub struct RwLock {
-    lock: Mutex,
-    cond: MovableCondvar,
-    state: UnsafeCell<State>,
-}
-
-pub type MovableRwLock = RwLock;
-
-enum State {
-    Unlocked,
-    Reading(usize),
-    Writing,
-}
-
-unsafe impl Send for RwLock {}
-unsafe impl Sync for RwLock {}
-
-// This rwlock implementation is a relatively simple implementation which has a
-// condition variable for readers/writers as well as a mutex protecting the
-// internal state of the lock. A current downside of the implementation is that
-// unlocking the lock will notify *all* waiters rather than just readers or just
-// writers. This can cause lots of "thundering stampede" problems. While
-// hopefully correct this implementation is very likely to want to be changed in
-// the future.
-
-impl RwLock {
-    pub const fn new() -> RwLock {
-        RwLock {
-            lock: Mutex::new(),
-            cond: MovableCondvar::new(),
-            state: UnsafeCell::new(State::Unlocked),
-        }
-    }
-
-    #[inline]
-    pub unsafe fn read(&self) {
-        self.lock.lock();
-        while !(*self.state.get()).inc_readers() {
-            self.cond.wait(&self.lock);
-        }
-        self.lock.unlock();
-    }
-
-    #[inline]
-    pub unsafe fn try_read(&self) -> bool {
-        self.lock.lock();
-        let ok = (*self.state.get()).inc_readers();
-        self.lock.unlock();
-        return ok;
-    }
-
-    #[inline]
-    pub unsafe fn write(&self) {
-        self.lock.lock();
-        while !(*self.state.get()).inc_writers() {
-            self.cond.wait(&self.lock);
-        }
-        self.lock.unlock();
-    }
-
-    #[inline]
-    pub unsafe fn try_write(&self) -> bool {
-        self.lock.lock();
-        let ok = (*self.state.get()).inc_writers();
-        self.lock.unlock();
-        return ok;
-    }
-
-    #[inline]
-    pub unsafe fn read_unlock(&self) {
-        self.lock.lock();
-        let notify = (*self.state.get()).dec_readers();
-        self.lock.unlock();
-        if notify {
-            // FIXME: should only wake up one of these some of the time
-            self.cond.notify_all();
-        }
-    }
-
-    #[inline]
-    pub unsafe fn write_unlock(&self) {
-        self.lock.lock();
-        (*self.state.get()).dec_writers();
-        self.lock.unlock();
-        // FIXME: should only wake up one of these some of the time
-        self.cond.notify_all();
-    }
-}
-
-impl State {
-    fn inc_readers(&mut self) -> bool {
-        match *self {
-            State::Unlocked => {
-                *self = State::Reading(1);
-                true
-            }
-            State::Reading(ref mut cnt) => {
-                *cnt += 1;
-                true
-            }
-            State::Writing => false,
-        }
-    }
-
-    fn inc_writers(&mut self) -> bool {
-        match *self {
-            State::Unlocked => {
-                *self = State::Writing;
-                true
-            }
-            State::Reading(_) | State::Writing => false,
-        }
-    }
-
-    fn dec_readers(&mut self) -> bool {
-        let zero = match *self {
-            State::Reading(ref mut cnt) => {
-                *cnt -= 1;
-                *cnt == 0
-            }
-            State::Unlocked | State::Writing => invalid(),
-        };
-        if zero {
-            *self = State::Unlocked;
-        }
-        zero
-    }
-
-    fn dec_writers(&mut self) {
-        match *self {
-            State::Writing => {}
-            State::Unlocked | State::Reading(_) => invalid(),
-        }
-        *self = State::Unlocked;
-    }
-}
-
-fn invalid() -> ! {
-    panic!("inconsistent rwlock");
-}
diff --git a/library/std/src/sys/itron/mutex.rs b/library/std/src/sys/itron/mutex.rs
index 715e94c3b3d6..085662e6d44b 100644
--- a/library/std/src/sys/itron/mutex.rs
+++ b/library/std/src/sys/itron/mutex.rs
@@ -31,12 +31,6 @@ impl Mutex {
         Mutex { mtx: SpinIdOnceCell::new() }
     }
 
-    pub unsafe fn init(&mut self) {
-        // Initialize `self.mtx` eagerly
-        let id = new_mtx().unwrap_or_else(|e| fail(e, &"acre_mtx"));
-        unsafe { self.mtx.set_unchecked((id, ())) };
-    }
-
     /// Get the inner mutex's ID, which is lazily created.
     fn raw(&self) -> abi::ID {
         match self.mtx.get_or_try_init(|| new_mtx().map(|id| (id, ()))) {
diff --git a/library/std/src/sys/sgx/abi/thread.rs b/library/std/src/sys/sgx/abi/thread.rs
index ef55b821a2b6..2b23e368cc31 100644
--- a/library/std/src/sys/sgx/abi/thread.rs
+++ b/library/std/src/sys/sgx/abi/thread.rs
@@ -7,7 +7,11 @@ use fortanix_sgx_abi::Tcs;
 #[unstable(feature = "sgx_platform", issue = "56975")]
 pub fn current() -> Tcs {
     extern "C" {
-        fn get_tcs_addr() -> Tcs;
+        fn get_tcs_addr() -> *mut u8;
+    }
+    let addr = unsafe { get_tcs_addr() };
+    match Tcs::new(addr) {
+        Some(tcs) => tcs,
+        None => rtabort!("TCS must not be placed at address zero (this is a linker error)"),
     }
-    unsafe { get_tcs_addr() }
 }
diff --git a/library/std/src/sys/sgx/abi/usercalls/alloc.rs b/library/std/src/sys/sgx/abi/usercalls/alloc.rs
index 5409bd1777c2..0d934318c22a 100644
--- a/library/std/src/sys/sgx/abi/usercalls/alloc.rs
+++ b/library/std/src/sys/sgx/abi/usercalls/alloc.rs
@@ -316,9 +316,9 @@ where
 //   | small1 | Chunk smaller than 8 bytes
 //   +--------+
 fn region_as_aligned_chunks(ptr: *const u8, len: usize) -> (usize, usize, usize) {
-    let small0_size = if ptr as usize % 8 == 0 { 0 } else { 8 - ptr as usize % 8 };
-    let small1_size = (len - small0_size as usize) % 8;
-    let big_size = len - small0_size as usize - small1_size as usize;
+    let small0_size = if ptr.is_aligned_to(8) { 0 } else { 8 - ptr.addr() % 8 };
+    let small1_size = (len - small0_size) % 8;
+    let big_size = len - small0_size - small1_size;
 
     (small0_size, big_size, small1_size)
 }
@@ -364,8 +364,8 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize)
                     mfence
                     lfence
                     ",
-                    val = in(reg_byte) *src.offset(off as isize),
-                    dst = in(reg) dst.offset(off as isize),
+                    val = in(reg_byte) *src.add(off),
+                    dst = in(reg) dst.add(off),
                     seg_sel = in(reg) &mut seg_sel,
                     options(nostack, att_syntax)
                 );
@@ -378,8 +378,8 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize)
     assert!(is_enclave_range(src, len));
     assert!(is_user_range(dst, len));
     assert!(len < isize::MAX as usize);
-    assert!(!(src as usize).overflowing_add(len).1);
-    assert!(!(dst as usize).overflowing_add(len).1);
+    assert!(!src.addr().overflowing_add(len).1);
+    assert!(!dst.addr().overflowing_add(len).1);
 
     if len < 8 {
         // Can't align on 8 byte boundary: copy safely byte per byte
@@ -404,17 +404,17 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize)
 
         unsafe {
             // Copy small0
-            copy_bytewise_to_userspace(src, dst, small0_size as _);
+            copy_bytewise_to_userspace(src, dst, small0_size);
 
             // Copy big
-            let big_src = src.offset(small0_size as _);
-            let big_dst = dst.offset(small0_size as _);
-            copy_quadwords(big_src as _, big_dst, big_size);
+            let big_src = src.add(small0_size);
+            let big_dst = dst.add(small0_size);
+            copy_quadwords(big_src, big_dst, big_size);
 
             // Copy small1
-            let small1_src = src.offset(big_size as isize + small0_size as isize);
-            let small1_dst = dst.offset(big_size as isize + small0_size as isize);
-            copy_bytewise_to_userspace(small1_src, small1_dst, small1_size as _);
+            let small1_src = src.add(big_size + small0_size);
+            let small1_dst = dst.add(big_size + small0_size);
+            copy_bytewise_to_userspace(small1_src, small1_dst, small1_size);
         }
     }
 }
diff --git a/library/std/src/sys/sgx/mod.rs b/library/std/src/sys/sgx/mod.rs
index 696400670e04..b1d32929ecfd 100644
--- a/library/std/src/sys/sgx/mod.rs
+++ b/library/std/src/sys/sgx/mod.rs
@@ -47,7 +47,7 @@ pub mod locks {
 
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
-pub unsafe fn init(argc: isize, argv: *const *const u8) {
+pub unsafe fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) {
     unsafe {
         args::init(argc, argv);
     }
diff --git a/library/std/src/sys/sgx/mutex.rs b/library/std/src/sys/sgx/mutex.rs
index 513cd77fd2aa..aa747d56b0d3 100644
--- a/library/std/src/sys/sgx/mutex.rs
+++ b/library/std/src/sys/sgx/mutex.rs
@@ -20,9 +20,6 @@ impl Mutex {
         Mutex { inner: SpinMutex::new(WaitVariable::new(false)) }
     }
 
-    #[inline]
-    pub unsafe fn init(&mut self) {}
-
     #[inline]
     pub unsafe fn lock(&self) {
         let mut guard = self.inner.lock();
diff --git a/library/std/src/sys/solid/mod.rs b/library/std/src/sys/solid/mod.rs
index 778a589d1b72..5867979a2a72 100644
--- a/library/std/src/sys/solid/mod.rs
+++ b/library/std/src/sys/solid/mod.rs
@@ -56,7 +56,7 @@ pub mod locks {
 
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
-pub unsafe fn init(_argc: isize, _argv: *const *const u8) {}
+pub unsafe fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {}
 
 // SAFETY: must be called only once during runtime cleanup.
 pub unsafe fn cleanup() {}
diff --git a/library/std/src/sys/solid/os.rs b/library/std/src/sys/solid/os.rs
index b5649d6e0ffb..eecb347e599e 100644
--- a/library/std/src/sys/solid/os.rs
+++ b/library/std/src/sys/solid/os.rs
@@ -8,7 +8,7 @@ use crate::os::{
     solid::ffi::{OsStrExt, OsStringExt},
 };
 use crate::path::{self, PathBuf};
-use crate::sys_common::rwlock::StaticRwLock;
+use crate::sync::RwLock;
 use crate::vec;
 
 use super::{error, itron, memchr};
@@ -78,7 +78,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
 }
 
-static ENV_LOCK: StaticRwLock = StaticRwLock::new();
+static ENV_LOCK: RwLock<()> = RwLock::new(());
 
 pub struct Env {
     iter: vec::IntoIter<(OsString, OsString)>,
diff --git a/library/std/src/sys/unix/locks/fuchsia_mutex.rs b/library/std/src/sys/unix/locks/fuchsia_mutex.rs
index ce427599c3bd..117611ce43f2 100644
--- a/library/std/src/sys/unix/locks/fuchsia_mutex.rs
+++ b/library/std/src/sys/unix/locks/fuchsia_mutex.rs
@@ -85,9 +85,6 @@ impl Mutex {
         Mutex { futex: AtomicU32::new(UNLOCKED) }
     }
 
-    #[inline]
-    pub unsafe fn init(&mut self) {}
-
     #[inline]
     pub unsafe fn try_lock(&self) -> bool {
         let thread_self = zx_thread_self();
@@ -138,7 +135,7 @@ impl Mutex {
                 }
             }
 
-            // The state has changed or a wakeup occured, try to lock the mutex.
+            // The state has changed or a wakeup occurred, try to lock the mutex.
             match self.futex.compare_exchange(UNLOCKED, owned_state, Acquire, Relaxed) {
                 Ok(_) => return,
                 Err(updated) => state = updated,
diff --git a/library/std/src/sys/unix/locks/futex_mutex.rs b/library/std/src/sys/unix/locks/futex_mutex.rs
index 99ba86e5f996..33b13dad4d65 100644
--- a/library/std/src/sys/unix/locks/futex_mutex.rs
+++ b/library/std/src/sys/unix/locks/futex_mutex.rs
@@ -19,9 +19,6 @@ impl Mutex {
         Self { futex: AtomicU32::new(0) }
     }
 
-    #[inline]
-    pub unsafe fn init(&mut self) {}
-
     #[inline]
     pub unsafe fn try_lock(&self) -> bool {
         self.futex.compare_exchange(0, 1, Acquire, Relaxed).is_ok()
@@ -53,7 +50,7 @@ impl Mutex {
             // We avoid an unnecessary write if it as already set to 2,
             // to be friendlier for the caches.
             if state != 2 && self.futex.swap(2, Acquire) == 0 {
-                // We changed it from 0 to 2, so we just succesfully locked it.
+                // We changed it from 0 to 2, so we just successfully locked it.
                 return;
             }
 
diff --git a/library/std/src/sys/unix/locks/futex_rwlock.rs b/library/std/src/sys/unix/locks/futex_rwlock.rs
index b3bbbf743f84..0cc92244ecad 100644
--- a/library/std/src/sys/unix/locks/futex_rwlock.rs
+++ b/library/std/src/sys/unix/locks/futex_rwlock.rs
@@ -54,7 +54,7 @@ fn is_read_lockable(state: u32) -> bool {
     // We don't allow read-locking if there's readers waiting, even if the lock is unlocked
     // and there's no writers waiting. The only situation when this happens is after unlocking,
     // at which point the unlocking thread might be waking up writers, which have priority over readers.
-    // The unlocking thread will clear the readers waiting bit and wake up readers, if necssary.
+    // The unlocking thread will clear the readers waiting bit and wake up readers, if necessary.
     state & MASK < MAX_READERS && !has_readers_waiting(state) && !has_writers_waiting(state)
 }
 
diff --git a/library/std/src/sys/unix/locks/mod.rs b/library/std/src/sys/unix/locks/mod.rs
index f5f92f693583..9bb314b7010a 100644
--- a/library/std/src/sys/unix/locks/mod.rs
+++ b/library/std/src/sys/unix/locks/mod.rs
@@ -11,21 +11,21 @@ cfg_if::cfg_if! {
         mod futex_rwlock;
         mod futex_condvar;
         pub(crate) use futex_mutex::{Mutex, MovableMutex};
-        pub(crate) use futex_rwlock::{RwLock, MovableRwLock};
+        pub(crate) use futex_rwlock::MovableRwLock;
         pub(crate) use futex_condvar::MovableCondvar;
     } else if #[cfg(target_os = "fuchsia")] {
         mod fuchsia_mutex;
         mod futex_rwlock;
         mod futex_condvar;
         pub(crate) use fuchsia_mutex::{Mutex, MovableMutex};
-        pub(crate) use futex_rwlock::{RwLock, MovableRwLock};
+        pub(crate) use futex_rwlock::MovableRwLock;
         pub(crate) use futex_condvar::MovableCondvar;
     } else {
         mod pthread_mutex;
         mod pthread_rwlock;
         mod pthread_condvar;
         pub(crate) use pthread_mutex::{Mutex, MovableMutex};
-        pub(crate) use pthread_rwlock::{RwLock, MovableRwLock};
+        pub(crate) use pthread_rwlock::MovableRwLock;
         pub(crate) use pthread_condvar::MovableCondvar;
     }
 }
diff --git a/library/std/src/sys/unix/locks/pthread_mutex.rs b/library/std/src/sys/unix/locks/pthread_mutex.rs
index 98afee69ba62..5964935ddb54 100644
--- a/library/std/src/sys/unix/locks/pthread_mutex.rs
+++ b/library/std/src/sys/unix/locks/pthread_mutex.rs
@@ -52,7 +52,7 @@ impl Mutex {
         Mutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
     #[inline]
-    pub unsafe fn init(&mut self) {
+    unsafe fn init(&mut self) {
         // Issue #33770
         //
         // A pthread mutex initialized with PTHREAD_MUTEX_INITIALIZER will have
diff --git a/library/std/src/sys/unix/mod.rs b/library/std/src/sys/unix/mod.rs
index 3a3750930998..c84e292eac15 100644
--- a/library/std/src/sys/unix/mod.rs
+++ b/library/std/src/sys/unix/mod.rs
@@ -44,12 +44,13 @@ pub mod thread_parker;
 pub mod time;
 
 #[cfg(target_os = "espidf")]
-pub fn init(argc: isize, argv: *const *const u8) {}
+pub fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) {}
 
 #[cfg(not(target_os = "espidf"))]
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
-pub unsafe fn init(argc: isize, argv: *const *const u8) {
+// See `fn init()` in `library/std/src/rt.rs` for docs on `sigpipe`.
+pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
     // The standard streams might be closed on application startup. To prevent
     // std::io::{stdin, stdout,stderr} objects from using other unrelated file
     // resources opened later, we reopen standards streams when they are closed.
@@ -61,8 +62,9 @@ pub unsafe fn init(argc: isize, argv: *const *const u8) {
     // want!
     //
     // Hence, we set SIGPIPE to ignore when the program starts up in order
-    // to prevent this problem.
-    reset_sigpipe();
+    // to prevent this problem. Add `#[unix_sigpipe = "..."]` above `fn main()` to
+    // alter this behavior.
+    reset_sigpipe(sigpipe);
 
     stack_overflow::init();
     args::init(argc, argv);
@@ -151,9 +153,31 @@ pub unsafe fn init(argc: isize, argv: *const *const u8) {
         }
     }
 
-    unsafe fn reset_sigpipe() {
+    unsafe fn reset_sigpipe(#[allow(unused_variables)] sigpipe: u8) {
         #[cfg(not(any(target_os = "emscripten", target_os = "fuchsia", target_os = "horizon")))]
-        rtassert!(signal(libc::SIGPIPE, libc::SIG_IGN) != libc::SIG_ERR);
+        {
+            // We don't want to add this as a public type to libstd, nor do we
+            // want to `include!` a file from the compiler (which would break
+            // Miri and xargo for example), so we choose to duplicate these
+            // constants from `compiler/rustc_session/src/config/sigpipe.rs`.
+            // See the other file for docs. NOTE: Make sure to keep them in
+            // sync!
+            mod sigpipe {
+                pub const INHERIT: u8 = 1;
+                pub const SIG_IGN: u8 = 2;
+                pub const SIG_DFL: u8 = 3;
+            }
+
+            let handler = match sigpipe {
+                sigpipe::INHERIT => None,
+                sigpipe::SIG_IGN => Some(libc::SIG_IGN),
+                sigpipe::SIG_DFL => Some(libc::SIG_DFL),
+                _ => unreachable!(),
+            };
+            if let Some(handler) = handler {
+                rtassert!(signal(libc::SIGPIPE, handler) != libc::SIG_ERR);
+            }
+        }
     }
 }
 
diff --git a/library/std/src/sys/unix/os.rs b/library/std/src/sys/unix/os.rs
index 46545a0839fe..7c70ddbd9b98 100644
--- a/library/std/src/sys/unix/os.rs
+++ b/library/std/src/sys/unix/os.rs
@@ -17,10 +17,10 @@ use crate::path::{self, PathBuf};
 use crate::ptr;
 use crate::slice;
 use crate::str;
+use crate::sync::{PoisonError, RwLock};
 use crate::sys::cvt;
 use crate::sys::fd;
 use crate::sys::memchr;
-use crate::sys_common::rwlock::{StaticRwLock, StaticRwLockReadGuard};
 use crate::vec;
 
 #[cfg(all(target_env = "gnu", not(target_os = "vxworks")))]
@@ -125,7 +125,9 @@ pub fn error_string(errno: i32) -> String {
         }
 
         let p = p as *const _;
-        str::from_utf8(CStr::from_ptr(p).to_bytes()).unwrap().to_owned()
+        // We can't always expect a UTF-8 environment. When we don't get that luxury,
+        // it's better to give a low-quality error message than none at all.
+        String::from_utf8_lossy(CStr::from_ptr(p).to_bytes()).into()
     }
 }
 
@@ -501,10 +503,10 @@ pub unsafe fn environ() -> *mut *const *const c_char {
     ptr::addr_of_mut!(environ)
 }
 
-static ENV_LOCK: StaticRwLock = StaticRwLock::new();
+static ENV_LOCK: RwLock<()> = RwLock::new(());
 
-pub fn env_read_lock() -> StaticRwLockReadGuard {
-    ENV_LOCK.read()
+pub fn env_read_lock() -> impl Drop {
+    ENV_LOCK.read().unwrap_or_else(PoisonError::into_inner)
 }
 
 /// Returns a vector of (variable, value) byte-vector pairs for all the
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index 26ae62817713..2ff8e600f7c5 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -822,14 +822,14 @@ impl crate::os::linux::process::ChildExt for crate::process::Child {
         self.handle
             .pidfd
             .as_ref()
-            .ok_or_else(|| Error::new(ErrorKind::Other, "No pidfd was created."))
+            .ok_or_else(|| Error::new(ErrorKind::Uncategorized, "No pidfd was created."))
     }
 
     fn take_pidfd(&mut self) -> io::Result<PidFd> {
         self.handle
             .pidfd
             .take()
-            .ok_or_else(|| Error::new(ErrorKind::Other, "No pidfd was created."))
+            .ok_or_else(|| Error::new(ErrorKind::Uncategorized, "No pidfd was created."))
     }
 }
 
diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index 7db3065dee08..56bb71b5dcbd 100644
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -429,7 +429,7 @@ mod cgroups {
                         Some(b"") => Cgroup::V2,
                         Some(controllers)
                             if from_utf8(controllers)
-                                .is_ok_and(|c| c.split(",").any(|c| c == "cpu")) =>
+                                .is_ok_and(|c| c.split(',').any(|c| c == "cpu")) =>
                         {
                             Cgroup::V1
                         }
diff --git a/library/std/src/sys/unix/thread_parker/mod.rs b/library/std/src/sys/unix/thread_parker/mod.rs
new file mode 100644
index 000000000000..e2453580dc72
--- /dev/null
+++ b/library/std/src/sys/unix/thread_parker/mod.rs
@@ -0,0 +1,21 @@
+//! Thread parking on systems without futex support.
+
+#![cfg(not(any(
+    target_os = "linux",
+    target_os = "android",
+    all(target_os = "emscripten", target_feature = "atomics"),
+    target_os = "freebsd",
+    target_os = "openbsd",
+    target_os = "dragonfly",
+    target_os = "fuchsia",
+)))]
+
+cfg_if::cfg_if! {
+    if #[cfg(target_os = "netbsd")] {
+        mod netbsd;
+        pub use netbsd::Parker;
+    } else {
+        mod pthread;
+        pub use pthread::Parker;
+    }
+}
diff --git a/library/std/src/sys/unix/thread_parker/netbsd.rs b/library/std/src/sys/unix/thread_parker/netbsd.rs
new file mode 100644
index 000000000000..7657605b52f0
--- /dev/null
+++ b/library/std/src/sys/unix/thread_parker/netbsd.rs
@@ -0,0 +1,113 @@
+use crate::ffi::{c_int, c_void};
+use crate::pin::Pin;
+use crate::ptr::{null, null_mut};
+use crate::sync::atomic::{
+    AtomicU64,
+    Ordering::{Acquire, Relaxed, Release},
+};
+use crate::time::Duration;
+use libc::{_lwp_self, clockid_t, lwpid_t, time_t, timespec, CLOCK_MONOTONIC};
+
+extern "C" {
+    fn ___lwp_park60(
+        clock_id: clockid_t,
+        flags: c_int,
+        ts: *mut timespec,
+        unpark: lwpid_t,
+        hint: *const c_void,
+        unparkhint: *const c_void,
+    ) -> c_int;
+    fn _lwp_unpark(lwp: lwpid_t, hint: *const c_void) -> c_int;
+}
+
+/// The thread is not parked and the token is not available.
+///
+/// Zero cannot be a valid LWP id, since it is used as empty value for the unpark
+/// argument in _lwp_park.
+const EMPTY: u64 = 0;
+/// The token is available. Do not park anymore.
+const NOTIFIED: u64 = u64::MAX;
+
+pub struct Parker {
+    /// The parker state. Contains either one of the two state values above or the LWP
+    /// id of the parked thread.
+    state: AtomicU64,
+}
+
+impl Parker {
+    pub unsafe fn new(parker: *mut Parker) {
+        parker.write(Parker { state: AtomicU64::new(EMPTY) })
+    }
+
+    // Does not actually need `unsafe` or `Pin`, but the pthread implementation does.
+    pub unsafe fn park(self: Pin<&Self>) {
+        // If the token has already been made available, we can skip
+        // a bit of work, so check for it here.
+        if self.state.load(Acquire) != NOTIFIED {
+            let parked = _lwp_self() as u64;
+            let hint = self.state.as_mut_ptr().cast();
+            if self.state.compare_exchange(EMPTY, parked, Relaxed, Acquire).is_ok() {
+                // Loop to guard against spurious wakeups.
+                loop {
+                    ___lwp_park60(0, 0, null_mut(), 0, hint, null());
+                    if self.state.load(Acquire) == NOTIFIED {
+                        break;
+                    }
+                }
+            }
+        }
+
+        // At this point, the change to NOTIFIED has always been observed with acquire
+        // ordering, so we can just use a relaxed store here (instead of a swap).
+        self.state.store(EMPTY, Relaxed);
+    }
+
+    // Does not actually need `unsafe` or `Pin`, but the pthread implementation does.
+    pub unsafe fn park_timeout(self: Pin<&Self>, dur: Duration) {
+        if self.state.load(Acquire) != NOTIFIED {
+            let parked = _lwp_self() as u64;
+            let hint = self.state.as_mut_ptr().cast();
+            let mut timeout = timespec {
+                // Saturate so that the operation will definitely time out
+                // (even if it is after the heat death of the universe).
+                tv_sec: dur.as_secs().try_into().ok().unwrap_or(time_t::MAX),
+                tv_nsec: dur.subsec_nanos().into(),
+            };
+
+            if self.state.compare_exchange(EMPTY, parked, Relaxed, Acquire).is_ok() {
+                // Timeout needs to be mutable since it is modified on NetBSD 9.0 and
+                // above.
+                ___lwp_park60(CLOCK_MONOTONIC, 0, &mut timeout, 0, hint, null());
+                // Use a swap to get acquire ordering even if the token was set after
+                // the timeout occurred.
+                self.state.swap(EMPTY, Acquire);
+                return;
+            }
+        }
+
+        self.state.store(EMPTY, Relaxed);
+    }
+
+    // Does not actually need `Pin`, but the pthread implementation does.
+    pub fn unpark(self: Pin<&Self>) {
+        let state = self.state.swap(NOTIFIED, Release);
+        if !matches!(state, EMPTY | NOTIFIED) {
+            let lwp = state as lwpid_t;
+            let hint = self.state.as_mut_ptr().cast();
+
+            // If the parking thread terminated and did not actually park, this will
+            // probably return an error, which is OK. In the worst case, another
+            // thread has received the same LWP id. It will then receive a spurious
+            // wakeup, but those are allowable per the API contract. The same reasoning
+            // applies if a timeout occurred before this call, but the state was not
+            // yet reset.
+
+            // SAFETY:
+            // The syscall has no invariants to hold. Only unsafe because it is an
+            // extern function.
+            unsafe {
+                _lwp_unpark(lwp, hint);
+            }
+        }
+    }
+}
diff --git a/library/std/src/sys/unix/thread_parker.rs b/library/std/src/sys/unix/thread_parker/pthread.rs
similarity index 97%
rename from library/std/src/sys/unix/thread_parker.rs
rename to library/std/src/sys/unix/thread_parker/pthread.rs
index ca1a7138fded..3dfc0026ed1a 100644
--- a/library/std/src/sys/unix/thread_parker.rs
+++ b/library/std/src/sys/unix/thread_parker/pthread.rs
@@ -1,15 +1,5 @@
 //! Thread parking without `futex` using the `pthread` synchronization primitives.
 
-#![cfg(not(any(
-    target_os = "linux",
-    target_os = "android",
-    all(target_os = "emscripten", target_feature = "atomics"),
-    target_os = "freebsd",
-    target_os = "openbsd",
-    target_os = "dragonfly",
-    target_os = "fuchsia",
-)))]
-
 use crate::cell::UnsafeCell;
 use crate::marker::PhantomPinned;
 use crate::pin::Pin;
@@ -59,8 +49,8 @@ unsafe fn wait_timeout(
         target_os = "espidf"
     ))]
     let (now, dur) = {
-        use super::time::SystemTime;
         use crate::cmp::min;
+        use crate::sys::time::SystemTime;
 
         // OSX implementation of `pthread_cond_timedwait` is buggy
         // with super long durations. When duration is greater than
@@ -85,7 +75,7 @@ unsafe fn wait_timeout(
         target_os = "espidf"
     )))]
     let (now, dur) = {
-        use super::time::Timespec;
+        use crate::sys::time::Timespec;
 
         (Timespec::now(libc::CLOCK_MONOTONIC), dur)
     };
diff --git a/library/std/src/sys/unsupported/common.rs b/library/std/src/sys/unsupported/common.rs
index 4c9ade4a8c79..5cd9e57de19e 100644
--- a/library/std/src/sys/unsupported/common.rs
+++ b/library/std/src/sys/unsupported/common.rs
@@ -6,7 +6,7 @@ pub mod memchr {
 
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
-pub unsafe fn init(_argc: isize, _argv: *const *const u8) {}
+pub unsafe fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {}
 
 // SAFETY: must be called only once during runtime cleanup.
 // NOTE: this is not guaranteed to run, for example when the program aborts.
diff --git a/library/std/src/sys/unsupported/locks/condvar.rs b/library/std/src/sys/unsupported/locks/condvar.rs
index e703fd0d2699..527a26a12bce 100644
--- a/library/std/src/sys/unsupported/locks/condvar.rs
+++ b/library/std/src/sys/unsupported/locks/condvar.rs
@@ -7,6 +7,7 @@ pub type MovableCondvar = Condvar;
 
 impl Condvar {
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Condvar {
         Condvar {}
     }
diff --git a/library/std/src/sys/unsupported/locks/mod.rs b/library/std/src/sys/unsupported/locks/mod.rs
index d412ff152a04..602a2d6231a2 100644
--- a/library/std/src/sys/unsupported/locks/mod.rs
+++ b/library/std/src/sys/unsupported/locks/mod.rs
@@ -3,4 +3,4 @@ mod mutex;
 mod rwlock;
 pub use condvar::{Condvar, MovableCondvar};
 pub use mutex::{MovableMutex, Mutex};
-pub use rwlock::{MovableRwLock, RwLock};
+pub use rwlock::MovableRwLock;
diff --git a/library/std/src/sys/unsupported/locks/mutex.rs b/library/std/src/sys/unsupported/locks/mutex.rs
index d7cb12e0cf9a..87ea475c6e3e 100644
--- a/library/std/src/sys/unsupported/locks/mutex.rs
+++ b/library/std/src/sys/unsupported/locks/mutex.rs
@@ -12,13 +12,11 @@ unsafe impl Sync for Mutex {} // no threads on this platform
 
 impl Mutex {
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Mutex {
         Mutex { locked: Cell::new(false) }
     }
 
-    #[inline]
-    pub unsafe fn init(&mut self) {}
-
     #[inline]
     pub unsafe fn lock(&self) {
         assert_eq!(self.locked.replace(true), false, "cannot recursively acquire mutex");
diff --git a/library/std/src/sys/unsupported/locks/rwlock.rs b/library/std/src/sys/unsupported/locks/rwlock.rs
index aca5fb7152c9..5292691b9555 100644
--- a/library/std/src/sys/unsupported/locks/rwlock.rs
+++ b/library/std/src/sys/unsupported/locks/rwlock.rs
@@ -12,6 +12,7 @@ unsafe impl Sync for RwLock {} // no threads on this platform
 
 impl RwLock {
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> RwLock {
         RwLock { mode: Cell::new(0) }
     }
diff --git a/library/std/src/sys/wasm/mod.rs b/library/std/src/sys/wasm/mod.rs
index 4159efe2a052..93838390bee6 100644
--- a/library/std/src/sys/wasm/mod.rs
+++ b/library/std/src/sys/wasm/mod.rs
@@ -57,7 +57,7 @@ cfg_if::cfg_if! {
             mod futex_rwlock;
             pub(crate) use futex_condvar::{Condvar, MovableCondvar};
             pub(crate) use futex_mutex::{Mutex, MovableMutex};
-            pub(crate) use futex_rwlock::{RwLock, MovableRwLock};
+            pub(crate) use futex_rwlock::MovableRwLock;
         }
         #[path = "atomics/futex.rs"]
         pub mod futex;
diff --git a/library/std/src/sys/windows/alloc.rs b/library/std/src/sys/windows/alloc.rs
index fe00c08aa6a9..d53ea16005fa 100644
--- a/library/std/src/sys/windows/alloc.rs
+++ b/library/std/src/sys/windows/alloc.rs
@@ -16,6 +16,7 @@ mod tests;
 // Flag to indicate that the memory returned by `HeapAlloc` should be zeroed.
 const HEAP_ZERO_MEMORY: c::DWORD = 0x00000008;
 
+#[link(name = "kernel32")]
 extern "system" {
     // Get a handle to the default heap of the current process, or null if the operation fails.
     //
diff --git a/library/std/src/sys/windows/c.rs b/library/std/src/sys/windows/c.rs
index c99c8efe4367..c61a7e7d1e4a 100644
--- a/library/std/src/sys/windows/c.rs
+++ b/library/std/src/sys/windows/c.rs
@@ -66,6 +66,7 @@ pub type LPSYSTEM_INFO = *mut SYSTEM_INFO;
 pub type LPWSABUF = *mut WSABUF;
 pub type LPWSAOVERLAPPED = *mut c_void;
 pub type LPWSAOVERLAPPED_COMPLETION_ROUTINE = *mut c_void;
+pub type BCRYPT_ALG_HANDLE = LPVOID;
 
 pub type PCONDITION_VARIABLE = *mut CONDITION_VARIABLE;
 pub type PLARGE_INTEGER = *mut c_longlong;
@@ -285,6 +286,8 @@ pub fn nt_success(status: NTSTATUS) -> bool {
     status >= 0
 }
 
+// "RNG\0"
+pub const BCRYPT_RNG_ALGORITHM: &[u16] = &[b'R' as u16, b'N' as u16, b'G' as u16, 0];
 pub const BCRYPT_USE_SYSTEM_PREFERRED_RNG: DWORD = 0x00000002;
 
 #[repr(C)]
@@ -454,6 +457,12 @@ pub enum FILE_INFO_BY_HANDLE_CLASS {
     MaximumFileInfoByHandlesClass,
 }
 
+#[repr(C)]
+pub struct FILE_ATTRIBUTE_TAG_INFO {
+    pub FileAttributes: DWORD,
+    pub ReparseTag: DWORD,
+}
+
 #[repr(C)]
 pub struct FILE_DISPOSITION_INFO {
     pub DeleteFile: BOOLEAN,
@@ -808,10 +817,6 @@ if #[cfg(not(target_vendor = "uwp"))] {
 
     #[link(name = "advapi32")]
     extern "system" {
-        // Forbidden when targeting UWP
-        #[link_name = "SystemFunction036"]
-        pub fn RtlGenRandom(RandomBuffer: *mut u8, RandomBufferLength: ULONG) -> BOOLEAN;
-
         // Allowed but unused by UWP
         pub fn OpenProcessToken(
             ProcessHandle: HANDLE,
@@ -1223,11 +1228,18 @@ extern "system" {
     // >= Vista / Server 2008
     // https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom
     pub fn BCryptGenRandom(
-        hAlgorithm: LPVOID,
+        hAlgorithm: BCRYPT_ALG_HANDLE,
         pBuffer: *mut u8,
         cbBuffer: ULONG,
         dwFlags: ULONG,
     ) -> NTSTATUS;
+    pub fn BCryptOpenAlgorithmProvider(
+        phalgorithm: *mut BCRYPT_ALG_HANDLE,
+        pszAlgId: LPCWSTR,
+        pszimplementation: LPCWSTR,
+        dwflags: ULONG,
+    ) -> NTSTATUS;
+    pub fn BCryptCloseAlgorithmProvider(hAlgorithm: BCRYPT_ALG_HANDLE, dwFlags: ULONG) -> NTSTATUS;
 }
 
 // Functions that aren't available on every version of Windows that we support,
diff --git a/library/std/src/sys/windows/cmath.rs b/library/std/src/sys/windows/cmath.rs
index 1a5421facd0c..43ab8c7ee659 100644
--- a/library/std/src/sys/windows/cmath.rs
+++ b/library/std/src/sys/windows/cmath.rs
@@ -44,7 +44,7 @@ mod shims {
 }
 
 // On 32-bit x86 MSVC these functions aren't defined, so we just define shims
-// which promote everything fo f64, perform the calculation, and then demote
+// which promote everything to f64, perform the calculation, and then demote
 // back to f32. While not precisely correct should be "correct enough" for now.
 #[cfg(all(target_env = "msvc", target_arch = "x86"))]
 mod shims {
diff --git a/library/std/src/sys/windows/fs.rs b/library/std/src/sys/windows/fs.rs
index 0aa7c50ded1c..155d0297e49a 100644
--- a/library/std/src/sys/windows/fs.rs
+++ b/library/std/src/sys/windows/fs.rs
@@ -3,7 +3,7 @@ use crate::os::windows::prelude::*;
 use crate::ffi::OsString;
 use crate::fmt;
 use crate::io::{self, BorrowedCursor, Error, IoSlice, IoSliceMut, SeekFrom};
-use crate::mem;
+use crate::mem::{self, MaybeUninit};
 use crate::os::windows::io::{AsHandle, BorrowedHandle};
 use crate::path::{Path, PathBuf};
 use crate::ptr;
@@ -326,9 +326,15 @@ impl File {
             cvt(c::GetFileInformationByHandle(self.handle.as_raw_handle(), &mut info))?;
             let mut reparse_tag = 0;
             if info.dwFileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
-                let mut b = Align8([0u8; c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
-                if let Ok((_, buf)) = self.reparse_point(&mut b) {
-                    reparse_tag = (*buf).ReparseTag;
+                let mut attr_tag: c::FILE_ATTRIBUTE_TAG_INFO = mem::zeroed();
+                cvt(c::GetFileInformationByHandleEx(
+                    self.handle.as_raw_handle(),
+                    c::FileAttributeTagInfo,
+                    ptr::addr_of_mut!(attr_tag).cast(),
+                    mem::size_of::<c::FILE_ATTRIBUTE_TAG_INFO>().try_into().unwrap(),
+                ))?;
+                if attr_tag.FileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
+                    reparse_tag = attr_tag.ReparseTag;
                 }
             }
             Ok(FileAttr {
@@ -389,9 +395,15 @@ impl File {
             attr.file_size = info.AllocationSize as u64;
             attr.number_of_links = Some(info.NumberOfLinks);
             if attr.file_type().is_reparse_point() {
-                let mut b = Align8([0; c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
-                if let Ok((_, buf)) = self.reparse_point(&mut b) {
-                    attr.reparse_tag = (*buf).ReparseTag;
+                let mut attr_tag: c::FILE_ATTRIBUTE_TAG_INFO = mem::zeroed();
+                cvt(c::GetFileInformationByHandleEx(
+                    self.handle.as_raw_handle(),
+                    c::FileAttributeTagInfo,
+                    ptr::addr_of_mut!(attr_tag).cast(),
+                    mem::size_of::<c::FILE_ATTRIBUTE_TAG_INFO>().try_into().unwrap(),
+                ))?;
+                if attr_tag.FileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
+                    attr.reparse_tag = attr_tag.ReparseTag;
                 }
             }
             Ok(attr)
@@ -463,7 +475,7 @@ impl File {
     // avoid narrowing provenance to the actual `REPARSE_DATA_BUFFER`.
     fn reparse_point(
         &self,
-        space: &mut Align8<[u8]>,
+        space: &mut Align8<[MaybeUninit<u8>]>,
     ) -> io::Result<(c::DWORD, *const c::REPARSE_DATA_BUFFER)> {
         unsafe {
             let mut bytes = 0;
@@ -488,7 +500,7 @@ impl File {
     }
 
     fn readlink(&self) -> io::Result<PathBuf> {
-        let mut space = Align8([0u8; c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
+        let mut space = Align8([MaybeUninit::<u8>::uninit(); c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
         let (_bytes, buf) = self.reparse_point(&mut space)?;
         unsafe {
             let (path_buffer, subst_off, subst_len, relative) = match (*buf).ReparseTag {
@@ -658,12 +670,16 @@ impl File {
 
 /// A buffer for holding directory entries.
 struct DirBuff {
-    buffer: Box<Align8<[u8; Self::BUFFER_SIZE]>>,
+    buffer: Box<Align8<[MaybeUninit<u8>; Self::BUFFER_SIZE]>>,
 }
 impl DirBuff {
     const BUFFER_SIZE: usize = 1024;
     fn new() -> Self {
-        Self { buffer: Box::new(Align8([0u8; Self::BUFFER_SIZE])) }
+        Self {
+            // Safety: `Align8<[MaybeUninit<u8>; N]>` does not need
+            // initialization.
+            buffer: unsafe { Box::new_uninit().assume_init() },
+        }
     }
     fn capacity(&self) -> usize {
         self.buffer.0.len()
@@ -676,8 +692,8 @@ impl DirBuff {
         DirBuffIter::new(self)
     }
 }
-impl AsRef<[u8]> for DirBuff {
-    fn as_ref(&self) -> &[u8] {
+impl AsRef<[MaybeUninit<u8>]> for DirBuff {
+    fn as_ref(&self) -> &[MaybeUninit<u8>] {
         &self.buffer.0
     }
 }
@@ -686,7 +702,7 @@ impl AsRef<[u8]> for DirBuff {
 ///
 /// Currently only returns file names (UTF-16 encoded).
 struct DirBuffIter<'a> {
-    buffer: Option<&'a [u8]>,
+    buffer: Option<&'a [MaybeUninit<u8>]>,
     cursor: usize,
 }
 impl<'a> DirBuffIter<'a> {
@@ -701,9 +717,13 @@ impl<'a> Iterator for DirBuffIter<'a> {
         let buffer = &self.buffer?[self.cursor..];
 
         // Get the name and next entry from the buffer.
-        // SAFETY: The buffer contains a `FILE_ID_BOTH_DIR_INFO` struct but the
-        // last field (the file name) is unsized. So an offset has to be
-        // used to get the file name slice.
+        // SAFETY:
+        // - The buffer contains a `FILE_ID_BOTH_DIR_INFO` struct but the last
+        //   field (the file name) is unsized. So an offset has to be used to
+        //   get the file name slice.
+        // - The OS has guaranteed initialization of the fields of
+        //   `FILE_ID_BOTH_DIR_INFO` and the trailing filename (for at least
+        //   `FileNameLength` bytes)
         let (name, is_directory, next_entry) = unsafe {
             let info = buffer.as_ptr().cast::<c::FILE_ID_BOTH_DIR_INFO>();
             // Guaranteed to be aligned in documentation for
@@ -1349,7 +1369,7 @@ fn symlink_junction_inner(original: &Path, junction: &Path) -> io::Result<()> {
     let h = f.as_inner().as_raw_handle();
 
     unsafe {
-        let mut data = Align8([0u8; c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
+        let mut data = Align8([MaybeUninit::<u8>::uninit(); c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
         let data_ptr = data.0.as_mut_ptr();
         let db = data_ptr.cast::<c::REPARSE_MOUNTPOINT_DATA_BUFFER>();
         let buf = ptr::addr_of_mut!((*db).ReparseTarget).cast::<c::WCHAR>();
diff --git a/library/std/src/sys/windows/locks/mod.rs b/library/std/src/sys/windows/locks/mod.rs
index d412ff152a04..602a2d6231a2 100644
--- a/library/std/src/sys/windows/locks/mod.rs
+++ b/library/std/src/sys/windows/locks/mod.rs
@@ -3,4 +3,4 @@ mod mutex;
 mod rwlock;
 pub use condvar::{Condvar, MovableCondvar};
 pub use mutex::{MovableMutex, Mutex};
-pub use rwlock::{MovableRwLock, RwLock};
+pub use rwlock::MovableRwLock;
diff --git a/library/std/src/sys/windows/locks/mutex.rs b/library/std/src/sys/windows/locks/mutex.rs
index f91e8f9f59a1..91207f5f4665 100644
--- a/library/std/src/sys/windows/locks/mutex.rs
+++ b/library/std/src/sys/windows/locks/mutex.rs
@@ -37,8 +37,6 @@ impl Mutex {
     pub const fn new() -> Mutex {
         Mutex { srwlock: UnsafeCell::new(c::SRWLOCK_INIT) }
     }
-    #[inline]
-    pub unsafe fn init(&mut self) {}
 
     #[inline]
     pub unsafe fn lock(&self) {
diff --git a/library/std/src/sys/windows/mod.rs b/library/std/src/sys/windows/mod.rs
index 340cae4066bf..eab9b961279c 100644
--- a/library/std/src/sys/windows/mod.rs
+++ b/library/std/src/sys/windows/mod.rs
@@ -48,7 +48,7 @@ cfg_if::cfg_if! {
 
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
-pub unsafe fn init(_argc: isize, _argv: *const *const u8) {
+pub unsafe fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {
     stack_overflow::init();
 
     // Normally, `thread::spawn` will call `Thread::set_name` but since this thread already
diff --git a/library/std/src/sys/windows/path.rs b/library/std/src/sys/windows/path.rs
index a0f822070992..beeca1917a9a 100644
--- a/library/std/src/sys/windows/path.rs
+++ b/library/std/src/sys/windows/path.rs
@@ -198,14 +198,7 @@ fn parse_next_component(path: &OsStr, verbatim: bool) -> (&OsStr, &OsStr) {
 
     match path.bytes().iter().position(|&x| separator(x)) {
         Some(separator_start) => {
-            let mut separator_end = separator_start + 1;
-
-            // a series of multiple separator characters is treated as a single separator,
-            // except in verbatim paths
-            while !verbatim && separator_end < path.len() && separator(path.bytes()[separator_end])
-            {
-                separator_end += 1;
-            }
+            let separator_end = separator_start + 1;
 
             let component = &path.bytes()[..separator_start];
 
diff --git a/library/std/src/sys/windows/path/tests.rs b/library/std/src/sys/windows/path/tests.rs
index 2f7ec433bf26..623c6236166d 100644
--- a/library/std/src/sys/windows/path/tests.rs
+++ b/library/std/src/sys/windows/path/tests.rs
@@ -31,16 +31,6 @@ fn test_parse_next_component() {
         parse_next_component(OsStr::new(r"servershare"), false),
         (OsStr::new(r"servershare"), OsStr::new(""))
     );
-
-    assert_eq!(
-        parse_next_component(OsStr::new(r"server/\//\/\\\\/////\/share"), false),
-        (OsStr::new(r"server"), OsStr::new(r"share"))
-    );
-
-    assert_eq!(
-        parse_next_component(OsStr::new(r"server\\\\\\\\\\\\\\share"), true),
-        (OsStr::new(r"server"), OsStr::new(r"\\\\\\\\\\\\\share"))
-    );
 }
 
 #[test]
@@ -115,7 +105,7 @@ fn test_parse_prefix_verbatim_device() {
     assert_eq!(prefix, parse_prefix(r"\\?/C:\windows\system32\notepad.exe"));
 }
 
-// See #93586 for more infomation.
+// See #93586 for more information.
 #[test]
 fn test_windows_prefix_components() {
     use crate::path::Path;
@@ -126,3 +116,22 @@ fn test_windows_prefix_components() {
     assert_eq!(drive.as_os_str(), OsStr::new("C:"));
     assert_eq!(components.as_path(), Path::new(""));
 }
+
+/// See #101358.
+///
+/// Note that the exact behaviour here may change in the future.
+/// In which case this test will need to adjusted.
+#[test]
+fn broken_unc_path() {
+    use crate::path::Component;
+
+    let mut components = Path::new(r"\\foo\\bar\\").components();
+    assert_eq!(components.next(), Some(Component::RootDir));
+    assert_eq!(components.next(), Some(Component::Normal("foo".as_ref())));
+    assert_eq!(components.next(), Some(Component::Normal("bar".as_ref())));
+
+    let mut components = Path::new("//foo//bar//").components();
+    assert_eq!(components.next(), Some(Component::RootDir));
+    assert_eq!(components.next(), Some(Component::Normal("foo".as_ref())));
+    assert_eq!(components.next(), Some(Component::Normal("bar".as_ref())));
+}
diff --git a/library/std/src/sys/windows/rand.rs b/library/std/src/sys/windows/rand.rs
index f8fd93a7398e..b5a49489d3fb 100644
--- a/library/std/src/sys/windows/rand.rs
+++ b/library/std/src/sys/windows/rand.rs
@@ -1,35 +1,106 @@
-use crate::io;
+//! # Random key generation
+//!
+//! This module wraps the RNG provided by the OS. There are a few different
+//! ways to interface with the OS RNG so it's worth exploring each of the options.
+//! Note that at the time of writing these all go through the (undocumented)
+//! `bcryptPrimitives.dll` but they use different route to get there.
+//!
+//! Originally we were using [`RtlGenRandom`], however that function is
+//! deprecated and warns it "may be altered or unavailable in subsequent versions".
+//!
+//! So we switched to [`BCryptGenRandom`] with the `BCRYPT_USE_SYSTEM_PREFERRED_RNG`
+//! flag to query and find the system configured RNG. However, this change caused a small
+//! but significant number of users to experience panics caused by a failure of
+//! this function. See [#94098].
+//!
+//! The current version falls back to using `BCryptOpenAlgorithmProvider` if
+//! `BCRYPT_USE_SYSTEM_PREFERRED_RNG` fails for any reason.
+//!
+//! [#94098]: https://github.com/rust-lang/rust/issues/94098
+//! [`RtlGenRandom`]: https://docs.microsoft.com/en-us/windows/win32/api/ntsecapi/nf-ntsecapi-rtlgenrandom
+//! [`BCryptGenRandom`]: https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom
 use crate::mem;
 use crate::ptr;
 use crate::sys::c;
 
+/// Generates high quality secure random keys for use by [`HashMap`].
+///
+/// This is used to seed the default [`RandomState`].
+///
+/// [`HashMap`]: crate::collections::HashMap
+/// [`RandomState`]: crate::collections::hash_map::RandomState
 pub fn hashmap_random_keys() -> (u64, u64) {
-    let mut v = (0, 0);
-    let ret = unsafe {
-        c::BCryptGenRandom(
-            ptr::null_mut(),
-            &mut v as *mut _ as *mut u8,
-            mem::size_of_val(&v) as c::ULONG,
-            c::BCRYPT_USE_SYSTEM_PREFERRED_RNG,
-        )
-    };
-    if ret != 0 { fallback_rng() } else { v }
+    Rng::SYSTEM.gen_random_keys().unwrap_or_else(fallback_rng)
 }
 
-/// Generate random numbers using the fallback RNG function (RtlGenRandom)
-#[cfg(not(target_vendor = "uwp"))]
+struct Rng {
+    algorithm: c::BCRYPT_ALG_HANDLE,
+    flags: u32,
+}
+impl Rng {
+    const SYSTEM: Self = unsafe { Self::new(ptr::null_mut(), c::BCRYPT_USE_SYSTEM_PREFERRED_RNG) };
+
+    /// Create the RNG from an existing algorithm handle.
+    ///
+    /// # Safety
+    ///
+    /// The handle must either be null or a valid algorithm handle.
+    const unsafe fn new(algorithm: c::BCRYPT_ALG_HANDLE, flags: u32) -> Self {
+        Self { algorithm, flags }
+    }
+
+    /// Open a handle to the RNG algorithm.
+    fn open() -> Result<Self, c::NTSTATUS> {
+        use crate::sync::atomic::AtomicPtr;
+        use crate::sync::atomic::Ordering::{Acquire, Release};
+
+        // An atomic is used so we don't need to reopen the handle every time.
+        static HANDLE: AtomicPtr<crate::ffi::c_void> = AtomicPtr::new(ptr::null_mut());
+
+        let mut handle = HANDLE.load(Acquire);
+        if handle.is_null() {
+            let status = unsafe {
+                c::BCryptOpenAlgorithmProvider(
+                    &mut handle,
+                    c::BCRYPT_RNG_ALGORITHM.as_ptr(),
+                    ptr::null(),
+                    0,
+                )
+            };
+            if c::nt_success(status) {
+                // If another thread opens a handle first then use that handle instead.
+                let result = HANDLE.compare_exchange(ptr::null_mut(), handle, Release, Acquire);
+                if let Err(previous_handle) = result {
+                    // Close our handle and return the previous one.
+                    unsafe { c::BCryptCloseAlgorithmProvider(handle, 0) };
+                    handle = previous_handle;
+                }
+                Ok(unsafe { Self::new(handle, 0) })
+            } else {
+                Err(status)
+            }
+        } else {
+            Ok(unsafe { Self::new(handle, 0) })
+        }
+    }
+
+    fn gen_random_keys(self) -> Result<(u64, u64), c::NTSTATUS> {
+        let mut v = (0, 0);
+        let status = unsafe {
+            let size = mem::size_of_val(&v).try_into().unwrap();
+            c::BCryptGenRandom(self.algorithm, ptr::addr_of_mut!(v).cast(), size, self.flags)
+        };
+        if c::nt_success(status) { Ok(v) } else { Err(status) }
+    }
+}
+
+/// Generate random numbers using the fallback RNG function
 #[inline(never)]
-fn fallback_rng() -> (u64, u64) {
-    let mut v = (0, 0);
-    let ret =
-        unsafe { c::RtlGenRandom(&mut v as *mut _ as *mut u8, mem::size_of_val(&v) as c::ULONG) };
-
-    if ret != 0 { v } else { panic!("fallback RNG broken: {}", io::Error::last_os_error()) }
-}
-
-/// We can't use RtlGenRandom with UWP, so there is no fallback
-#[cfg(target_vendor = "uwp")]
-#[inline(never)]
-fn fallback_rng() -> (u64, u64) {
-    panic!("fallback RNG broken: RtlGenRandom() not supported on UWP");
+fn fallback_rng(rng_status: c::NTSTATUS) -> (u64, u64) {
+    match Rng::open().and_then(|rng| rng.gen_random_keys()) {
+        Ok(keys) => keys,
+        Err(status) => {
+            panic!("RNG broken: {rng_status:#x}, fallback RNG broken: {status:#x}")
+        }
+    }
 }
diff --git a/library/std/src/sys_common/condvar.rs b/library/std/src/sys_common/condvar.rs
index f3ac1061b893..8bc5b24115d1 100644
--- a/library/std/src/sys_common/condvar.rs
+++ b/library/std/src/sys_common/condvar.rs
@@ -15,6 +15,7 @@ pub struct Condvar {
 impl Condvar {
     /// Creates a new condition variable for use.
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self { inner: imp::MovableCondvar::new(), check: CondvarCheck::new() }
     }
diff --git a/library/std/src/sys_common/condvar/check.rs b/library/std/src/sys_common/condvar/check.rs
index ce8f36704877..4ac9e62bf869 100644
--- a/library/std/src/sys_common/condvar/check.rs
+++ b/library/std/src/sys_common/condvar/check.rs
@@ -50,6 +50,7 @@ pub struct NoCheck;
 
 #[allow(dead_code)]
 impl NoCheck {
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self
     }
diff --git a/library/std/src/sys_common/mutex.rs b/library/std/src/sys_common/mutex.rs
index 48479f5bdb3f..7b9f7ef54878 100644
--- a/library/std/src/sys_common/mutex.rs
+++ b/library/std/src/sys_common/mutex.rs
@@ -61,6 +61,7 @@ unsafe impl Sync for MovableMutex {}
 impl MovableMutex {
     /// Creates a new mutex.
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self(imp::MovableMutex::new())
     }
diff --git a/library/std/src/sys_common/remutex.rs b/library/std/src/sys_common/remutex.rs
index 8921af311d41..b448ae3a9977 100644
--- a/library/std/src/sys_common/remutex.rs
+++ b/library/std/src/sys_common/remutex.rs
@@ -1,13 +1,11 @@
 #[cfg(all(test, not(target_os = "emscripten")))]
 mod tests;
 
+use super::mutex as sys;
 use crate::cell::UnsafeCell;
-use crate::marker::PhantomPinned;
 use crate::ops::Deref;
 use crate::panic::{RefUnwindSafe, UnwindSafe};
-use crate::pin::Pin;
 use crate::sync::atomic::{AtomicUsize, Ordering::Relaxed};
-use crate::sys::locks as sys;
 
 /// A re-entrant mutual exclusion
 ///
@@ -41,11 +39,10 @@ use crate::sys::locks as sys;
 /// synchronization is left to the mutex, making relaxed memory ordering for
 /// the `owner` field fine in all cases.
 pub struct ReentrantMutex<T> {
-    mutex: sys::Mutex,
+    mutex: sys::MovableMutex,
     owner: AtomicUsize,
     lock_count: UnsafeCell<u32>,
     data: T,
-    _pinned: PhantomPinned,
 }
 
 unsafe impl<T: Send> Send for ReentrantMutex<T> {}
@@ -68,39 +65,22 @@ impl<T> RefUnwindSafe for ReentrantMutex<T> {}
 /// guarded data.
 #[must_use = "if unused the ReentrantMutex will immediately unlock"]
 pub struct ReentrantMutexGuard<'a, T: 'a> {
-    lock: Pin<&'a ReentrantMutex<T>>,
+    lock: &'a ReentrantMutex<T>,
 }
 
 impl<T> !Send for ReentrantMutexGuard<'_, T> {}
 
 impl<T> ReentrantMutex<T> {
     /// Creates a new reentrant mutex in an unlocked state.
-    ///
-    /// # Unsafety
-    ///
-    /// This function is unsafe because it is required that `init` is called
-    /// once this mutex is in its final resting place, and only then are the
-    /// lock/unlock methods safe.
-    pub const unsafe fn new(t: T) -> ReentrantMutex<T> {
+    pub const fn new(t: T) -> ReentrantMutex<T> {
         ReentrantMutex {
-            mutex: sys::Mutex::new(),
+            mutex: sys::MovableMutex::new(),
             owner: AtomicUsize::new(0),
             lock_count: UnsafeCell::new(0),
             data: t,
-            _pinned: PhantomPinned,
         }
     }
 
-    /// Initializes this mutex so it's ready for use.
-    ///
-    /// # Unsafety
-    ///
-    /// Unsafe to call more than once, and must be called after this will no
-    /// longer move in memory.
-    pub unsafe fn init(self: Pin<&mut Self>) {
-        self.get_unchecked_mut().mutex.init()
-    }
-
     /// Acquires a mutex, blocking the current thread until it is able to do so.
     ///
     /// This function will block the caller until it is available to acquire the mutex.
@@ -113,15 +93,14 @@ impl<T> ReentrantMutex<T> {
     /// If another user of this mutex panicked while holding the mutex, then
     /// this call will return failure if the mutex would otherwise be
     /// acquired.
-    pub fn lock(self: Pin<&Self>) -> ReentrantMutexGuard<'_, T> {
+    pub fn lock(&self) -> ReentrantMutexGuard<'_, T> {
         let this_thread = current_thread_unique_ptr();
-        // Safety: We only touch lock_count when we own the lock,
-        // and since self is pinned we can safely call the lock() on the mutex.
+        // Safety: We only touch lock_count when we own the lock.
         unsafe {
             if self.owner.load(Relaxed) == this_thread {
                 self.increment_lock_count();
             } else {
-                self.mutex.lock();
+                self.mutex.raw_lock();
                 self.owner.store(this_thread, Relaxed);
                 debug_assert_eq!(*self.lock_count.get(), 0);
                 *self.lock_count.get() = 1;
@@ -142,10 +121,9 @@ impl<T> ReentrantMutex<T> {
     /// If another user of this mutex panicked while holding the mutex, then
     /// this call will return failure if the mutex would otherwise be
     /// acquired.
-    pub fn try_lock(self: Pin<&Self>) -> Option<ReentrantMutexGuard<'_, T>> {
+    pub fn try_lock(&self) -> Option<ReentrantMutexGuard<'_, T>> {
         let this_thread = current_thread_unique_ptr();
-        // Safety: We only touch lock_count when we own the lock,
-        // and since self is pinned we can safely call the try_lock on the mutex.
+        // Safety: We only touch lock_count when we own the lock.
         unsafe {
             if self.owner.load(Relaxed) == this_thread {
                 self.increment_lock_count();
@@ -179,12 +157,12 @@ impl<T> Deref for ReentrantMutexGuard<'_, T> {
 impl<T> Drop for ReentrantMutexGuard<'_, T> {
     #[inline]
     fn drop(&mut self) {
-        // Safety: We own the lock, and the lock is pinned.
+        // Safety: We own the lock.
         unsafe {
             *self.lock.lock_count.get() -= 1;
             if *self.lock.lock_count.get() == 0 {
                 self.lock.owner.store(0, Relaxed);
-                self.lock.mutex.unlock();
+                self.lock.mutex.raw_unlock();
             }
         }
     }
diff --git a/library/std/src/sys_common/remutex/tests.rs b/library/std/src/sys_common/remutex/tests.rs
index 64873b850d3f..8e97ce11c34f 100644
--- a/library/std/src/sys_common/remutex/tests.rs
+++ b/library/std/src/sys_common/remutex/tests.rs
@@ -1,18 +1,11 @@
-use crate::boxed::Box;
 use crate::cell::RefCell;
-use crate::pin::Pin;
 use crate::sync::Arc;
 use crate::sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
 use crate::thread;
 
 #[test]
 fn smoke() {
-    let m = unsafe {
-        let mut m = Box::pin(ReentrantMutex::new(()));
-        m.as_mut().init();
-        m
-    };
-    let m = m.as_ref();
+    let m = ReentrantMutex::new(());
     {
         let a = m.lock();
         {
@@ -29,20 +22,15 @@ fn smoke() {
 
 #[test]
 fn is_mutex() {
-    let m = unsafe {
-        // FIXME: Simplify this if Arc gets an Arc::get_pin_mut.
-        let mut m = Arc::new(ReentrantMutex::new(RefCell::new(0)));
-        Pin::new_unchecked(Arc::get_mut_unchecked(&mut m)).init();
-        Pin::new_unchecked(m)
-    };
+    let m = Arc::new(ReentrantMutex::new(RefCell::new(0)));
     let m2 = m.clone();
-    let lock = m.as_ref().lock();
+    let lock = m.lock();
     let child = thread::spawn(move || {
-        let lock = m2.as_ref().lock();
+        let lock = m2.lock();
         assert_eq!(*lock.borrow(), 4950);
     });
     for i in 0..100 {
-        let lock = m.as_ref().lock();
+        let lock = m.lock();
         *lock.borrow_mut() += i;
     }
     drop(lock);
@@ -51,22 +39,17 @@ fn is_mutex() {
 
 #[test]
 fn trylock_works() {
-    let m = unsafe {
-        // FIXME: Simplify this if Arc gets an Arc::get_pin_mut.
-        let mut m = Arc::new(ReentrantMutex::new(()));
-        Pin::new_unchecked(Arc::get_mut_unchecked(&mut m)).init();
-        Pin::new_unchecked(m)
-    };
+    let m = Arc::new(ReentrantMutex::new(()));
     let m2 = m.clone();
-    let _lock = m.as_ref().try_lock();
-    let _lock2 = m.as_ref().try_lock();
+    let _lock = m.try_lock();
+    let _lock2 = m.try_lock();
     thread::spawn(move || {
-        let lock = m2.as_ref().try_lock();
+        let lock = m2.try_lock();
         assert!(lock.is_none());
     })
     .join()
     .unwrap();
-    let _lock3 = m.as_ref().try_lock();
+    let _lock3 = m.try_lock();
 }
 
 pub struct Answer<'a>(pub ReentrantMutexGuard<'a, RefCell<u32>>);
diff --git a/library/std/src/sys_common/rwlock.rs b/library/std/src/sys_common/rwlock.rs
index ba56f3a8f1b5..042981dac60b 100644
--- a/library/std/src/sys_common/rwlock.rs
+++ b/library/std/src/sys_common/rwlock.rs
@@ -1,65 +1,5 @@
 use crate::sys::locks as imp;
 
-/// An OS-based reader-writer lock, meant for use in static variables.
-///
-/// This rwlock does not implement poisoning.
-///
-/// This rwlock has a const constructor ([`StaticRwLock::new`]), does not
-/// implement `Drop` to cleanup resources.
-pub struct StaticRwLock(imp::RwLock);
-
-impl StaticRwLock {
-    /// Creates a new rwlock for use.
-    #[inline]
-    pub const fn new() -> Self {
-        Self(imp::RwLock::new())
-    }
-
-    /// Acquires shared access to the underlying lock, blocking the current
-    /// thread to do so.
-    ///
-    /// The lock is automatically unlocked when the returned guard is dropped.
-    #[inline]
-    pub fn read(&'static self) -> StaticRwLockReadGuard {
-        unsafe { self.0.read() };
-        StaticRwLockReadGuard(&self.0)
-    }
-
-    /// Acquires write access to the underlying lock, blocking the current thread
-    /// to do so.
-    ///
-    /// The lock is automatically unlocked when the returned guard is dropped.
-    #[inline]
-    pub fn write(&'static self) -> StaticRwLockWriteGuard {
-        unsafe { self.0.write() };
-        StaticRwLockWriteGuard(&self.0)
-    }
-}
-
-#[must_use]
-pub struct StaticRwLockReadGuard(&'static imp::RwLock);
-
-impl Drop for StaticRwLockReadGuard {
-    #[inline]
-    fn drop(&mut self) {
-        unsafe {
-            self.0.read_unlock();
-        }
-    }
-}
-
-#[must_use]
-pub struct StaticRwLockWriteGuard(&'static imp::RwLock);
-
-impl Drop for StaticRwLockWriteGuard {
-    #[inline]
-    fn drop(&mut self) {
-        unsafe {
-            self.0.write_unlock();
-        }
-    }
-}
-
 /// An OS-based reader-writer lock.
 ///
 /// This rwlock cleans up its resources in its `Drop` implementation and may
@@ -75,6 +15,7 @@ pub struct MovableRwLock(imp::MovableRwLock);
 impl MovableRwLock {
     /// Creates a new reader-writer lock for use.
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self(imp::MovableRwLock::new())
     }
diff --git a/library/std/src/sys_common/thread_parker/mod.rs b/library/std/src/sys_common/thread_parker/mod.rs
index cbd7832eb7a4..f86a9a555d32 100644
--- a/library/std/src/sys_common/thread_parker/mod.rs
+++ b/library/std/src/sys_common/thread_parker/mod.rs
@@ -7,6 +7,7 @@ cfg_if::cfg_if! {
         target_os = "openbsd",
         target_os = "dragonfly",
         target_os = "fuchsia",
+        target_os = "hermit",
     ))] {
         mod futex;
         pub use futex::Parker;
diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs
index a17185b6f707..ceea6986e333 100644
--- a/library/std/src/thread/mod.rs
+++ b/library/std/src/thread/mod.rs
@@ -116,7 +116,7 @@
 //! Threads are able to have associated names for identification purposes. By default, spawned
 //! threads are unnamed. To specify a name for a thread, build the thread with [`Builder`] and pass
 //! the desired thread name to [`Builder::name`]. To retrieve the thread name from within the
-//! thread, use [`Thread::name`]. A couple examples of where the name of a thread gets used:
+//! thread, use [`Thread::name`]. A couple of examples where the name of a thread gets used:
 //!
 //! * If a panic occurs in a named thread, the thread name will be printed in the panic message.
 //! * The thread name is provided to the OS where applicable (e.g., `pthread_setname_np` in
diff --git a/library/stdarch b/library/stdarch
index 42df7394d38b..699c093a4228 160000
--- a/library/stdarch
+++ b/library/stdarch
@@ -1 +1 @@
-Subproject commit 42df7394d38bc7b945116ea3ad8a7cbcd1db50a9
+Subproject commit 699c093a42283c07e9763b4c19439a900ae2d321
diff --git a/library/test/src/stats.rs b/library/test/src/stats.rs
index 40b05704b40c..b33b08012613 100644
--- a/library/test/src/stats.rs
+++ b/library/test/src/stats.rs
@@ -14,7 +14,7 @@ pub trait Stats {
     /// Sum of the samples.
     ///
     /// Note: this method sacrifices performance at the altar of accuracy
-    /// Depends on IEEE-754 arithmetic guarantees. See proof of correctness at:
+    /// Depends on IEEE 754 arithmetic guarantees. See proof of correctness at:
     /// ["Adaptive Precision Floating-Point Arithmetic and Fast Robust Geometric
     /// Predicates"][paper]
     ///
diff --git a/src/README.md b/src/README.md
index 3d2e6acd5764..90ab80269708 100644
--- a/src/README.md
+++ b/src/README.md
@@ -2,7 +2,7 @@ This directory contains the source code of the rust project, including:
 
 - The test suite
 - The bootstrapping build system
-- Various submodules for tools, like cargo, miri, etc.
+- Various submodules for tools, like cargo, etc.
 
 For more information on how various parts of the compiler work, see the [rustc dev guide].
 
diff --git a/src/bootstrap/Cargo.toml b/src/bootstrap/Cargo.toml
index 2dad41bb18fc..95e711737738 100644
--- a/src/bootstrap/Cargo.toml
+++ b/src/bootstrap/Cargo.toml
@@ -67,6 +67,7 @@ features = [
     "psapi",
     "impl-default",
     "timezoneapi",
+    "winbase",
 ]
 
 [dev-dependencies]
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index bd5790d2ea88..e96f8b0d3125 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -139,10 +139,8 @@ fn main() {
         // Cargo doesn't pass RUSTFLAGS to proc_macros:
         // https://github.com/rust-lang/cargo/issues/4423
         // Thus, if we are on stage 0, we explicitly set `--cfg=bootstrap`.
-        // We also declare that the flag is expected, which is mainly needed for
-        // later stages so that they don't warn about #[cfg(bootstrap)],
-        // but enabling it for stage 0 too lets any warnings, if they occur,
-        // occur more early on, e.g. about #[cfg(bootstrap = "foo")].
+        // We also declare that the flag is expected, which we need to do to not
+        // get warnings about it being unexpected.
         if stage == "0" {
             cmd.arg("--cfg=bootstrap");
         }
diff --git a/src/bootstrap/bin/rustdoc.rs b/src/bootstrap/bin/rustdoc.rs
index 87c1d22e7714..e69cab956c50 100644
--- a/src/bootstrap/bin/rustdoc.rs
+++ b/src/bootstrap/bin/rustdoc.rs
@@ -11,6 +11,7 @@ include!("../dylib_util.rs");
 
 fn main() {
     let args = env::args_os().skip(1).collect::<Vec<_>>();
+    let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
     let rustdoc = env::var_os("RUSTDOC_REAL").expect("RUSTDOC_REAL was not set");
     let libdir = env::var_os("RUSTDOC_LIBDIR").expect("RUSTDOC_LIBDIR was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
@@ -62,6 +63,16 @@ fn main() {
             cmd.arg("-Clink-arg=-Wl,--threads=1");
         }
     }
+    // Cargo doesn't pass RUSTDOCFLAGS to proc_macros:
+    // https://github.com/rust-lang/cargo/issues/4423
+    // Thus, if we are on stage 0, we explicitly set `--cfg=bootstrap`.
+    // We also declare that the flag is expected, which we need to do to not
+    // get warnings about it being unexpected.
+    if stage == "0" {
+        cmd.arg("--cfg=bootstrap");
+    }
+    cmd.arg("-Zunstable-options");
+    cmd.arg("--check-cfg=values(bootstrap)");
 
     if verbose > 1 {
         eprintln!(
diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index 9301c5a2ff30..57128685d911 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -85,7 +85,7 @@ def _download(path, url, probably_big, verbose, exception):
             option = "-#"
         else:
             option = "-s"
-        # If curl is not present on Win32, we shoud not sys.exit
+        # If curl is not present on Win32, we should not sys.exit
         #   but raise `CalledProcessError` or `OSError` instead
         require(["curl", "--version"], exception=platform_is_win32)
         run(["curl", option,
@@ -732,9 +732,19 @@ class RustBuild(object):
             (os.pathsep + env["LIBRARY_PATH"]) \
             if "LIBRARY_PATH" in env else ""
 
+        # Export Stage0 snapshot compiler related env variables
+        build_section = "target.{}".format(self.build)
+        host_triple_sanitized = self.build.replace("-", "_")
+        var_data = {
+            "CC": "cc", "CXX": "cxx", "LD": "linker", "AR": "ar", "RANLIB": "ranlib"
+        }
+        for var_name, toml_key in var_data.items():
+            toml_val = self.get_toml(toml_key, build_section)
+            if toml_val != None:
+                env["{}_{}".format(var_name, host_triple_sanitized)] = toml_val
+
         # preserve existing RUSTFLAGS
         env.setdefault("RUSTFLAGS", "")
-        build_section = "target.{}".format(self.build)
         target_features = []
         if self.get_toml("crt-static", build_section) == "true":
             target_features += ["+crt-static"]
@@ -742,9 +752,6 @@ class RustBuild(object):
             target_features += ["-crt-static"]
         if target_features:
             env["RUSTFLAGS"] += " -C target-feature=" + (",".join(target_features))
-        target_linker = self.get_toml("linker", build_section)
-        if target_linker is not None:
-            env["RUSTFLAGS"] += " -C linker=" + target_linker
         env["RUSTFLAGS"] += " -Wrust_2018_idioms -Wunused_lifetimes"
         env["RUSTFLAGS"] += " -Wsemicolon_in_expressions_from_macros"
         if self.get_toml("deny-warnings", "rust") != "false":
@@ -771,7 +778,8 @@ class RustBuild(object):
         elif color == "never":
             args.append("--color=never")
 
-        run(args, env=env, verbose=self.verbose)
+        # Run this from the source directory so cargo finds .cargo/config
+        run(args, env=env, verbose=self.verbose, cwd=self.rust_root)
 
     def build_triple(self):
         """Build triple as in LLVM
@@ -793,6 +801,8 @@ class RustBuild(object):
 
     def check_vendored_status(self):
         """Check that vendoring is configured properly"""
+        # keep this consistent with the equivalent check in rustbuild:
+        # https://github.com/rust-lang/rust/blob/a8a33cf27166d3eabaffc58ed3799e054af3b0c6/src/bootstrap/lib.rs#L399-L405
         if 'SUDO_USER' in os.environ and not self.use_vendored_sources:
             if os.getuid() == 0:
                 self.use_vendored_sources = True
diff --git a/src/bootstrap/build.rs b/src/bootstrap/build.rs
index ab34d5c1e550..cd1f418028c6 100644
--- a/src/bootstrap/build.rs
+++ b/src/bootstrap/build.rs
@@ -1,43 +1,7 @@
-use env::consts::{EXE_EXTENSION, EXE_SUFFIX};
 use std::env;
-use std::ffi::OsString;
-use std::path::PathBuf;
-
-/// Given an executable called `name`, return the filename for the
-/// executable for a particular target.
-pub fn exe(name: &PathBuf) -> PathBuf {
-    if EXE_EXTENSION != "" && name.extension() != Some(EXE_EXTENSION.as_ref()) {
-        let mut name: OsString = name.clone().into();
-        name.push(EXE_SUFFIX);
-        name.into()
-    } else {
-        name.clone()
-    }
-}
 
 fn main() {
     let host = env::var("HOST").unwrap();
     println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=RUSTC");
     println!("cargo:rustc-env=BUILD_TRIPLE={}", host);
-
-    // This may not be a canonicalized path.
-    let mut rustc = PathBuf::from(env::var_os("RUSTC").unwrap());
-
-    if rustc.is_relative() {
-        println!("cargo:rerun-if-env-changed=PATH");
-        for dir in env::split_paths(&env::var_os("PATH").unwrap_or_default()) {
-            let absolute = dir.join(&exe(&rustc));
-            if absolute.exists() {
-                rustc = absolute;
-                break;
-            }
-        }
-    }
-    assert!(rustc.is_absolute());
-
-    // FIXME: if the path is not utf-8, this is going to break. Unfortunately
-    // Cargo doesn't have a way for us to specify non-utf-8 paths easily, so
-    // we'll need to invent some encoding scheme if this becomes a problem.
-    println!("cargo:rustc-env=RUSTC={}", rustc.to_str().unwrap());
 }
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 1e764811ea79..415774d7255d 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -708,6 +708,7 @@ impl<'a> Builder<'a> {
             Kind::Dist => describe!(
                 dist::Docs,
                 dist::RustcDocs,
+                dist::JsonDocs,
                 dist::Mingw,
                 dist::Rustc,
                 dist::Std,
@@ -723,6 +724,7 @@ impl<'a> Builder<'a> {
                 dist::Miri,
                 dist::LlvmTools,
                 dist::RustDev,
+                dist::Bootstrap,
                 dist::Extended,
                 // It seems that PlainSourceTarball somehow changes how some of the tools
                 // perceive their dependencies (see #93033) which would invalidate fingerprints
@@ -946,7 +948,7 @@ impl<'a> Builder<'a> {
         };
         patchelf.args(&[OsString::from("--set-rpath"), rpath_entries]);
         if !fname.extension().map_or(false, |ext| ext == "so") {
-            // Finally, set the corret .interp for binaries
+            // Finally, set the correct .interp for binaries
             let dynamic_linker_path = nix_deps_dir.join("nix-support/dynamic-linker");
             // FIXME: can we support utf8 here? `args` doesn't accept Vec<u8>, only OsString ...
             let dynamic_linker = t!(String::from_utf8(t!(fs::read(dynamic_linker_path))));
@@ -962,7 +964,7 @@ impl<'a> Builder<'a> {
         let tempfile = self.tempdir().join(dest_path.file_name().unwrap());
         // While bootstrap itself only supports http and https downloads, downstream forks might
         // need to download components from other protocols. The match allows them adding more
-        // protocols without worrying about merge conficts if we change the HTTP implementation.
+        // protocols without worrying about merge conflicts if we change the HTTP implementation.
         match url.split_once("://").map(|(proto, _)| proto) {
             Some("http") | Some("https") => {
                 self.download_http_with_retries(&tempfile, url, help_on_error)
@@ -1325,6 +1327,9 @@ impl<'a> Builder<'a> {
     ) -> Cargo {
         let mut cargo = Command::new(&self.initial_cargo);
         let out_dir = self.stage_out(compiler, mode);
+        // Run cargo from the source root so it can find .cargo/config.
+        // This matters when using vendoring and the working directory is outside the repository.
+        cargo.current_dir(&self.src);
 
         // Codegen backends are not yet tracked by -Zbinary-dep-depinfo,
         // so we need to explicitly clear out if they've been updated.
@@ -1552,13 +1557,12 @@ impl<'a> Builder<'a> {
         match mode {
             Mode::ToolBootstrap => {
                 // Restrict the allowed features to those passed by rustbuild, so we don't depend on nightly accidentally.
-                // HACK: because anyhow does feature detection in build.rs, we need to allow the backtrace feature too.
-                rustflags.arg("-Zallow-features=binary-dep-depinfo,backtrace");
+                rustflags.arg("-Zallow-features=binary-dep-depinfo");
             }
             Mode::ToolStd => {
                 // Right now this is just compiletest and a few other tools that build on stable.
                 // Allow them to use `feature(test)`, but nothing else.
-                rustflags.arg("-Zallow-features=binary-dep-depinfo,test,backtrace,proc_macro_internals,proc_macro_diagnostic,proc_macro_span");
+                rustflags.arg("-Zallow-features=binary-dep-depinfo,test,proc_macro_internals,proc_macro_diagnostic,proc_macro_span");
             }
             Mode::Std | Mode::Rustc | Mode::Codegen | Mode::ToolRustc => {}
         }
@@ -1940,25 +1944,26 @@ impl<'a> Builder<'a> {
                     _ => s.display().to_string(),
                 }
             };
+            let triple_underscored = target.triple.replace("-", "_");
             let cc = ccacheify(&self.cc(target));
-            cargo.env(format!("CC_{}", target.triple), &cc);
+            cargo.env(format!("CC_{}", triple_underscored), &cc);
 
             let cflags = self.cflags(target, GitRepo::Rustc, CLang::C).join(" ");
-            cargo.env(format!("CFLAGS_{}", target.triple), &cflags);
+            cargo.env(format!("CFLAGS_{}", triple_underscored), &cflags);
 
             if let Some(ar) = self.ar(target) {
                 let ranlib = format!("{} s", ar.display());
                 cargo
-                    .env(format!("AR_{}", target.triple), ar)
-                    .env(format!("RANLIB_{}", target.triple), ranlib);
+                    .env(format!("AR_{}", triple_underscored), ar)
+                    .env(format!("RANLIB_{}", triple_underscored), ranlib);
             }
 
             if let Ok(cxx) = self.cxx(target) {
                 let cxx = ccacheify(&cxx);
                 let cxxflags = self.cflags(target, GitRepo::Rustc, CLang::Cxx).join(" ");
                 cargo
-                    .env(format!("CXX_{}", target.triple), &cxx)
-                    .env(format!("CXXFLAGS_{}", target.triple), cxxflags);
+                    .env(format!("CXX_{}", triple_underscored), &cxx)
+                    .env(format!("CXXFLAGS_{}", triple_underscored), cxxflags);
             }
         }
 
diff --git a/src/bootstrap/builder/tests.rs b/src/bootstrap/builder/tests.rs
index 280eba75f0c1..88bbcc93d072 100644
--- a/src/bootstrap/builder/tests.rs
+++ b/src/bootstrap/builder/tests.rs
@@ -236,7 +236,7 @@ mod defaults {
     fn doc_default() {
         let mut config = configure("doc", &["A"], &["A"]);
         config.compiler_docs = true;
-        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false };
+        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false, json: false };
         let mut cache = run_build(&[], config);
         let a = TargetSelection::from_user("A");
 
@@ -587,7 +587,7 @@ mod dist {
     fn doc_ci() {
         let mut config = configure(&["A"], &["A"]);
         config.compiler_docs = true;
-        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false };
+        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false, json: false };
         let build = Build::new(config);
         let mut builder = Builder::new(&build);
         builder.run_step_descriptions(&Builder::get_step_descriptions(Kind::Doc), &[]);
diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index 5c085bedf0ee..229851238f1d 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -456,6 +456,8 @@ tool_check_step!(Rustdoc, "src/tools/rustdoc", "src/librustdoc", SourceType::InT
 // behavior, treat it as in-tree so that any new warnings in clippy will be
 // rejected.
 tool_check_step!(Clippy, "src/tools/clippy", SourceType::InTree);
+// Miri on the other hand is treated as out of tree, since InTree also causes it to
+// be run as part of `check`, which can fail on platforms which libffi-sys has no support for.
 tool_check_step!(Miri, "src/tools/miri", SourceType::Submodule);
 tool_check_step!(Rls, "src/tools/rls", SourceType::InTree);
 tool_check_step!(Rustfmt, "src/tools/rustfmt", SourceType::InTree);
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index c3aabb16a9b9..c13e83f6c861 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -1281,7 +1281,9 @@ impl Step for Assemble {
                 compiler: build_compiler,
                 target: target_compiler.host,
             });
-            builder.copy(&lld_wrapper_exe, &gcc_ld_dir.join(exe("ld", target_compiler.host)));
+            for name in crate::LLD_FILE_NAMES {
+                builder.copy(&lld_wrapper_exe, &gcc_ld_dir.join(exe(name, target_compiler.host)));
+            }
         }
 
         if builder.config.rust_codegen_backends.contains(&INTERNER.intern_str("llvm")) {
diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index 13e3049f2c81..74530dec97b7 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -388,6 +388,7 @@ impl PartialEq<&str> for TargetSelection {
 pub struct Target {
     /// Some(path to llvm-config) if using an external LLVM.
     pub llvm_config: Option<PathBuf>,
+    pub llvm_has_rust_patches: Option<bool>,
     /// Some(path to FileCheck) if one was specified.
     pub llvm_filecheck: Option<PathBuf>,
     pub llvm_libunwind: Option<LlvmLibunwind>,
@@ -733,6 +734,7 @@ define_config! {
         default_linker: Option<PathBuf> = "default-linker",
         linker: Option<String> = "linker",
         llvm_config: Option<String> = "llvm-config",
+        llvm_has_rust_patches: Option<bool> = "llvm-has-rust-patches",
         llvm_filecheck: Option<String> = "llvm-filecheck",
         llvm_libunwind: Option<String> = "llvm-libunwind",
         android_ndk: Option<String> = "android-ndk",
@@ -770,21 +772,20 @@ impl Config {
 
         // set by build.rs
         config.build = TargetSelection::from_user(&env!("BUILD_TRIPLE"));
+
         let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
         // Undo `src/bootstrap`
         config.src = manifest_dir.parent().unwrap().parent().unwrap().to_owned();
         config.out = PathBuf::from("build");
 
-        config.initial_cargo = PathBuf::from(env!("CARGO"));
-        config.initial_rustc = PathBuf::from(env!("RUSTC"));
-
         config
     }
 
     pub fn parse(args: &[String]) -> Config {
         let flags = Flags::parse(&args);
-
         let mut config = Config::default_opts();
+
+        // Set flags.
         config.exclude = flags.exclude.into_iter().map(|path| TaskPath::parse(path)).collect();
         config.include_default_paths = flags.include_default_paths;
         config.rustc_error_format = flags.rustc_error_format;
@@ -803,7 +804,49 @@ impl Config {
         config.llvm_profile_use = flags.llvm_profile_use;
         config.llvm_profile_generate = flags.llvm_profile_generate;
 
+        // Infer the rest of the configuration.
+
+        // Infer the source directory. This is non-trivial because we want to support a downloaded bootstrap binary,
+        // running on a completely machine from where it was compiled.
+        let mut cmd = Command::new("git");
+        // NOTE: we cannot support running from outside the repository because the only path we have available
+        // is set at compile time, which can be wrong if bootstrap was downloaded from source.
+        // We still support running outside the repository if we find we aren't in a git directory.
+        cmd.arg("rev-parse").arg("--show-toplevel");
+        // Discard stderr because we expect this to fail when building from a tarball.
+        let output = cmd
+            .stderr(std::process::Stdio::null())
+            .output()
+            .ok()
+            .and_then(|output| if output.status.success() { Some(output) } else { None });
+        if let Some(output) = output {
+            let git_root = String::from_utf8(output.stdout).unwrap();
+            // We need to canonicalize this path to make sure it uses backslashes instead of forward slashes.
+            let git_root = PathBuf::from(git_root.trim()).canonicalize().unwrap();
+            let s = git_root.to_str().unwrap();
+
+            // Bootstrap is quite bad at handling /? in front of paths
+            config.src = match s.strip_prefix("\\\\?\\") {
+                Some(p) => PathBuf::from(p),
+                None => PathBuf::from(git_root),
+            };
+        } else {
+            // We're building from a tarball, not git sources.
+            // We don't support pre-downloaded bootstrap in this case.
+        }
+
+        if cfg!(test) {
+            // Use the build directory of the original x.py invocation, so that we can set `initial_rustc` properly.
+            config.out = Path::new(
+                &env::var_os("CARGO_TARGET_DIR").expect("cargo test directly is not supported"),
+            )
+            .parent()
+            .unwrap()
+            .to_path_buf();
+        }
+
         let stage0_json = t!(std::fs::read(&config.src.join("src").join("stage0.json")));
+
         config.stage0_metadata = t!(serde_json::from_slice::<Stage0Metadata>(&stage0_json));
 
         #[cfg(test)]
@@ -859,7 +902,6 @@ impl Config {
 
         let build = toml.build.unwrap_or_default();
 
-        set(&mut config.initial_rustc, build.rustc.map(PathBuf::from));
         set(&mut config.out, flags.build_dir.or_else(|| build.build_dir.map(PathBuf::from)));
         // NOTE: Bootstrap spawns various commands with different working directories.
         // To avoid writing to random places on the file system, `config.out` needs to be an absolute path.
@@ -868,6 +910,16 @@ impl Config {
             config.out = crate::util::absolute(&config.out);
         }
 
+        config.initial_rustc = build
+            .rustc
+            .map(PathBuf::from)
+            .unwrap_or_else(|| config.out.join(config.build.triple).join("stage0/bin/rustc"));
+        config.initial_cargo = build
+            .cargo
+            .map(PathBuf::from)
+            .unwrap_or_else(|| config.out.join(config.build.triple).join("stage0/bin/cargo"));
+
+        // NOTE: it's important this comes *after* we set `initial_rustc` just above.
         if config.dry_run {
             let dir = config.out.join("tmp-dry-run");
             t!(fs::create_dir_all(&dir));
@@ -1109,6 +1161,7 @@ impl Config {
                 if let Some(ref s) = cfg.llvm_config {
                     target.llvm_config = Some(config.src.join(s));
                 }
+                target.llvm_has_rust_patches = cfg.llvm_has_rust_patches;
                 if let Some(ref s) = cfg.llvm_filecheck {
                     target.llvm_filecheck = Some(config.src.join(s));
                 }
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index c01afa1fd3b7..f387496883bb 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -35,18 +35,6 @@ pub fn tmpdir(builder: &Builder<'_>) -> PathBuf {
     builder.out.join("tmp/dist")
 }
 
-fn missing_tool(tool_name: &str, skip: bool) {
-    if skip {
-        println!("Unable to build {}, skipping dist", tool_name)
-    } else {
-        let help = "note: not all tools are available on all nightlies\nhelp: see https://forge.rust-lang.org/infra/toolstate.html for more information";
-        panic!(
-            "Unable to build submodule tool {} (use `missing-tools = true` to ignore this failure)\n{}",
-            tool_name, help
-        )
-    }
-}
-
 fn should_build_extended_tool(builder: &Builder<'_>, tool: &str) -> bool {
     if !builder.config.extended {
         return false;
@@ -87,6 +75,39 @@ impl Step for Docs {
     }
 }
 
+#[derive(Debug, PartialOrd, Ord, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct JsonDocs {
+    pub host: TargetSelection,
+}
+
+impl Step for JsonDocs {
+    type Output = Option<GeneratedTarball>;
+    const DEFAULT: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        let default = run.builder.config.docs;
+        run.alias("rust-docs-json").default_condition(default)
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(JsonDocs { host: run.target });
+    }
+
+    /// Builds the `rust-docs-json` installer component.
+    fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
+        let host = self.host;
+        builder.ensure(crate::doc::JsonStd { stage: builder.top_stage, target: host });
+
+        let dest = "share/doc/rust/json";
+
+        let mut tarball = Tarball::new(builder, "rust-docs-json", &host.triple);
+        tarball.set_product_name("Rust Documentation In JSON Format");
+        tarball.is_preview(true);
+        tarball.add_bulk_dir(&builder.json_doc_out(host), dest);
+        Some(tarball.generate())
+    }
+}
+
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct RustcDocs {
     pub host: TargetSelection,
@@ -423,8 +444,11 @@ impl Step for Rustc {
                 let gcc_lld_src_dir = src_dir.join("gcc-ld");
                 let gcc_lld_dst_dir = dst_dir.join("gcc-ld");
                 t!(fs::create_dir(&gcc_lld_dst_dir));
-                let exe_name = exe("ld", compiler.host);
-                builder.copy(&gcc_lld_src_dir.join(&exe_name), &gcc_lld_dst_dir.join(&exe_name));
+                for name in crate::LLD_FILE_NAMES {
+                    let exe_name = exe(name, compiler.host);
+                    builder
+                        .copy(&gcc_lld_src_dir.join(&exe_name), &gcc_lld_dst_dir.join(&exe_name));
+                }
             }
 
             // Man pages
@@ -1167,18 +1191,9 @@ impl Step for Miri {
         let compiler = self.compiler;
         let target = self.target;
 
-        let miri = builder
-            .ensure(tool::Miri { compiler, target, extra_features: Vec::new() })
-            .or_else(|| {
-                missing_tool("miri", builder.build.config.missing_tools);
-                None
-            })?;
-        let cargomiri = builder
-            .ensure(tool::CargoMiri { compiler, target, extra_features: Vec::new() })
-            .or_else(|| {
-                missing_tool("cargo miri", builder.build.config.missing_tools);
-                None
-            })?;
+        let miri = builder.ensure(tool::Miri { compiler, target, extra_features: Vec::new() })?;
+        let cargomiri =
+            builder.ensure(tool::CargoMiri { compiler, target, extra_features: Vec::new() })?;
 
         let mut tarball = Tarball::new(builder, "miri", &target.triple);
         tarball.set_overlay(OverlayKind::Miri);
@@ -1409,7 +1424,7 @@ impl Step for Extended {
 
         let xform = |p: &Path| {
             let mut contents = t!(fs::read_to_string(p));
-            for tool in &["rust-demangler", "rust-analyzer", "miri", "rustfmt"] {
+            for tool in &["rust-demangler"] {
                 if !built_tools.contains(tool) {
                     contents = filter(&contents, tool);
                 }
@@ -1449,7 +1464,9 @@ impl Step for Extended {
             prepare("rust-std");
             prepare("rust-analysis");
             prepare("clippy");
-            for tool in &["rust-docs", "rust-demangler", "rust-analyzer", "miri"] {
+            prepare("miri");
+            prepare("rust-analyzer");
+            for tool in &["rust-docs", "rust-demangler"] {
                 if built_tools.contains(tool) {
                     prepare(tool);
                 }
@@ -1508,7 +1525,9 @@ impl Step for Extended {
             prepare("rust-docs");
             prepare("rust-std");
             prepare("clippy");
-            for tool in &["rust-demangler", "rust-analyzer", "miri"] {
+            prepare("miri");
+            prepare("rust-analyzer");
+            for tool in &["rust-demangler"] {
                 if built_tools.contains(tool) {
                     prepare(tool);
                 }
@@ -1592,25 +1611,23 @@ impl Step for Extended {
                     .arg("-out")
                     .arg(exe.join("StdGroup.wxs")),
             );
-            if built_tools.contains("rust-analyzer") {
-                builder.run(
-                    Command::new(&heat)
-                        .current_dir(&exe)
-                        .arg("dir")
-                        .arg("rust-analyzer")
-                        .args(&heat_flags)
-                        .arg("-cg")
-                        .arg("RustAnalyzerGroup")
-                        .arg("-dr")
-                        .arg("RustAnalyzer")
-                        .arg("-var")
-                        .arg("var.RustAnalyzerDir")
-                        .arg("-out")
-                        .arg(exe.join("RustAnalyzerGroup.wxs"))
-                        .arg("-t")
-                        .arg(etc.join("msi/remove-duplicates.xsl")),
-                );
-            }
+            builder.run(
+                Command::new(&heat)
+                    .current_dir(&exe)
+                    .arg("dir")
+                    .arg("rust-analyzer")
+                    .args(&heat_flags)
+                    .arg("-cg")
+                    .arg("RustAnalyzerGroup")
+                    .arg("-dr")
+                    .arg("RustAnalyzer")
+                    .arg("-var")
+                    .arg("var.RustAnalyzerDir")
+                    .arg("-out")
+                    .arg(exe.join("RustAnalyzerGroup.wxs"))
+                    .arg("-t")
+                    .arg(etc.join("msi/remove-duplicates.xsl")),
+            );
             builder.run(
                 Command::new(&heat)
                     .current_dir(&exe)
@@ -1647,25 +1664,23 @@ impl Step for Extended {
                         .arg(etc.join("msi/remove-duplicates.xsl")),
                 );
             }
-            if built_tools.contains("miri") {
-                builder.run(
-                    Command::new(&heat)
-                        .current_dir(&exe)
-                        .arg("dir")
-                        .arg("miri")
-                        .args(&heat_flags)
-                        .arg("-cg")
-                        .arg("MiriGroup")
-                        .arg("-dr")
-                        .arg("Miri")
-                        .arg("-var")
-                        .arg("var.MiriDir")
-                        .arg("-out")
-                        .arg(exe.join("MiriGroup.wxs"))
-                        .arg("-t")
-                        .arg(etc.join("msi/remove-duplicates.xsl")),
-                );
-            }
+            builder.run(
+                Command::new(&heat)
+                    .current_dir(&exe)
+                    .arg("dir")
+                    .arg("miri")
+                    .args(&heat_flags)
+                    .arg("-cg")
+                    .arg("MiriGroup")
+                    .arg("-dr")
+                    .arg("Miri")
+                    .arg("-var")
+                    .arg("var.MiriDir")
+                    .arg("-out")
+                    .arg(exe.join("MiriGroup.wxs"))
+                    .arg("-t")
+                    .arg(etc.join("msi/remove-duplicates.xsl")),
+            );
             builder.run(
                 Command::new(&heat)
                     .current_dir(&exe)
@@ -1713,6 +1728,7 @@ impl Step for Extended {
                     .arg("-dStdDir=rust-std")
                     .arg("-dAnalysisDir=rust-analysis")
                     .arg("-dClippyDir=clippy")
+                    .arg("-dMiriDir=miri")
                     .arg("-arch")
                     .arg(&arch)
                     .arg("-out")
@@ -1726,9 +1742,6 @@ impl Step for Extended {
                 if built_tools.contains("rust-analyzer") {
                     cmd.arg("-dRustAnalyzerDir=rust-analyzer");
                 }
-                if built_tools.contains("miri") {
-                    cmd.arg("-dMiriDir=miri");
-                }
                 if target.ends_with("windows-gnu") {
                     cmd.arg("-dGccDir=rust-mingw");
                 }
@@ -1742,15 +1755,13 @@ impl Step for Extended {
             candle("CargoGroup.wxs".as_ref());
             candle("StdGroup.wxs".as_ref());
             candle("ClippyGroup.wxs".as_ref());
+            candle("MiriGroup.wxs".as_ref());
             if built_tools.contains("rust-demangler") {
                 candle("RustDemanglerGroup.wxs".as_ref());
             }
             if built_tools.contains("rust-analyzer") {
                 candle("RustAnalyzerGroup.wxs".as_ref());
             }
-            if built_tools.contains("miri") {
-                candle("MiriGroup.wxs".as_ref());
-            }
             candle("AnalysisGroup.wxs".as_ref());
 
             if target.ends_with("windows-gnu") {
@@ -1780,6 +1791,7 @@ impl Step for Extended {
                 .arg("StdGroup.wixobj")
                 .arg("AnalysisGroup.wixobj")
                 .arg("ClippyGroup.wixobj")
+                .arg("MiriGroup.wixobj")
                 .current_dir(&exe);
 
             if built_tools.contains("rust-analyzer") {
@@ -1788,9 +1800,6 @@ impl Step for Extended {
             if built_tools.contains("rust-demangler") {
                 cmd.arg("RustDemanglerGroup.wixobj");
             }
-            if built_tools.contains("miri") {
-                cmd.arg("MiriGroup.wixobj");
-            }
 
             if target.ends_with("windows-gnu") {
                 cmd.arg("GccGroup.wixobj");
@@ -1870,7 +1879,7 @@ fn maybe_install_llvm(builder: &Builder<'_>, target: TargetSelection, dst_libdir
         let mut cmd = Command::new(llvm_config);
         cmd.arg("--libfiles");
         builder.verbose(&format!("running {:?}", cmd));
-        let files = output(&mut cmd);
+        let files = if builder.config.dry_run { "".into() } else { output(&mut cmd) };
         let build_llvm_out = &builder.llvm_out(builder.config.build);
         let target_llvm_out = &builder.llvm_out(target);
         for file in files.trim_end().split(' ') {
@@ -2017,6 +2026,7 @@ impl Step for RustDev {
             "llvm-dwp",
             "llvm-nm",
             "llvm-dwarfdump",
+            "llvm-dis",
         ] {
             tarball.add_file(src_bindir.join(exe(bin, target)), "bin", 0o755);
         }
@@ -2047,6 +2057,41 @@ impl Step for RustDev {
     }
 }
 
+// Tarball intended for internal consumption to ease rustc/std development.
+//
+// Should not be considered stable by end users.
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub struct Bootstrap {
+    pub target: TargetSelection,
+}
+
+impl Step for Bootstrap {
+    type Output = Option<GeneratedTarball>;
+    const DEFAULT: bool = false;
+    const ONLY_HOSTS: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.alias("bootstrap")
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(Bootstrap { target: run.target });
+    }
+
+    fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
+        let target = self.target;
+
+        let tarball = Tarball::new(builder, "bootstrap", &target.triple);
+
+        let bootstrap_outdir = &builder.bootstrap_out;
+        for file in &["bootstrap", "llvm-config-wrapper", "rustc", "rustdoc", "sccache-plus-cl"] {
+            tarball.add_file(bootstrap_outdir.join(exe(file, target)), "bootstrap/bin", 0o755);
+        }
+
+        Some(tarball.generate())
+    }
+}
+
 /// Tarball containing a prebuilt version of the build-manifest tool, intended to be used by the
 /// release process to avoid cloning the monorepo and building stuff.
 ///
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 2852442d0be6..819af6587484 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -7,6 +7,7 @@
 //! Everything here is basically just a shim around calling either `rustbook` or
 //! `rustdoc`.
 
+use std::ffi::OsStr;
 use std::fs;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -383,15 +384,9 @@ impl Step for Standalone {
             }
 
             if filename == "not_found.md" {
-                cmd.arg("--markdown-css")
-                    .arg(format!("https://doc.rust-lang.org/rustdoc{}.css", &builder.version))
-                    .arg("--markdown-css")
-                    .arg("https://doc.rust-lang.org/rust.css");
+                cmd.arg("--markdown-css").arg("https://doc.rust-lang.org/rust.css");
             } else {
-                cmd.arg("--markdown-css")
-                    .arg(format!("rustdoc{}.css", &builder.version))
-                    .arg("--markdown-css")
-                    .arg("rust.css");
+                cmd.arg("--markdown-css").arg("rust.css");
             }
             builder.run(&mut cmd);
         }
@@ -431,49 +426,24 @@ impl Step for Std {
     fn run(self, builder: &Builder<'_>) {
         let stage = self.stage;
         let target = self.target;
-        builder.info(&format!("Documenting stage{} std ({})", stage, target));
-        if builder.no_std(target) == Some(true) {
-            panic!(
-                "building std documentation for no_std target {target} is not supported\n\
-                 Set `docs = false` in the config to disable documentation."
-            );
-        }
         let out = builder.doc_out(target);
         t!(fs::create_dir_all(&out));
-        let compiler = builder.compiler(stage, builder.config.build);
-
-        let out_dir = builder.stage_out(compiler, Mode::Std).join(target.triple).join("doc");
-
         t!(fs::copy(builder.src.join("src/doc/rust.css"), out.join("rust.css")));
 
-        let run_cargo_rustdoc_for = |package: &str| {
-            let mut cargo =
-                builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "rustdoc");
-            compile::std_cargo(builder, target, compiler.stage, &mut cargo);
+        let index_page = builder.src.join("src/doc/index.md").into_os_string();
+        let mut extra_args = vec![
+            OsStr::new("--markdown-css"),
+            OsStr::new("rust.css"),
+            OsStr::new("--markdown-no-toc"),
+            OsStr::new("--index-page"),
+            &index_page,
+        ];
 
-            cargo
-                .arg("-p")
-                .arg(package)
-                .arg("-Zskip-rustdoc-fingerprint")
-                .arg("--")
-                .arg("--markdown-css")
-                .arg("rust.css")
-                .arg("--markdown-no-toc")
-                .arg("-Z")
-                .arg("unstable-options")
-                .arg("--resource-suffix")
-                .arg(&builder.version)
-                .arg("--index-page")
-                .arg(&builder.src.join("src/doc/index.md"));
+        if !builder.config.docs_minification {
+            extra_args.push(OsStr::new("--disable-minification"));
+        }
 
-            if !builder.config.docs_minification {
-                cargo.arg("--disable-minification");
-            }
-
-            builder.run(&mut cargo.into());
-        };
-
-        let paths = builder
+        let requested_crates = builder
             .paths
             .iter()
             .map(components_simplified)
@@ -491,30 +461,20 @@ impl Step for Std {
             })
             .collect::<Vec<_>>();
 
-        // Only build the following crates. While we could just iterate over the
-        // folder structure, that would also build internal crates that we do
-        // not want to show in documentation. These crates will later be visited
-        // by the rustc step, so internal documentation will show them.
-        //
-        // Note that the order here is important! The crates need to be
-        // processed starting from the leaves, otherwise rustdoc will not
-        // create correct links between crates because rustdoc depends on the
-        // existence of the output directories to know if it should be a local
-        // or remote link.
-        let krates = ["core", "alloc", "std", "proc_macro", "test"];
-        for krate in &krates {
-            run_cargo_rustdoc_for(krate);
-            if paths.iter().any(|p| p == krate) {
-                // No need to document more of the libraries if we have the one we want.
-                break;
-            }
-        }
-        builder.cp_r(&out_dir, &out);
+        doc_std(
+            builder,
+            DocumentationFormat::HTML,
+            stage,
+            target,
+            &out,
+            &extra_args,
+            &requested_crates,
+        );
 
         // Look for library/std, library/core etc in the `x.py doc` arguments and
         // open the corresponding rendered docs.
-        for requested_crate in paths {
-            if krates.iter().any(|k| *k == requested_crate.as_str()) {
+        for requested_crate in requested_crates {
+            if STD_PUBLIC_CRATES.iter().any(|k| *k == requested_crate.as_str()) {
                 let index = out.join(requested_crate).join("index.html");
                 open(builder, &index);
             }
@@ -522,6 +482,134 @@ impl Step for Std {
     }
 }
 
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct JsonStd {
+    pub stage: u32,
+    pub target: TargetSelection,
+}
+
+impl Step for JsonStd {
+    type Output = ();
+    const DEFAULT: bool = false;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        let default = run.builder.config.docs && run.builder.config.cmd.json();
+        run.all_krates("test").path("library").default_condition(default)
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(Std { stage: run.builder.top_stage, target: run.target });
+    }
+
+    /// Build JSON documentation for the standard library crates.
+    ///
+    /// This is largely just a wrapper around `cargo doc`.
+    fn run(self, builder: &Builder<'_>) {
+        let stage = self.stage;
+        let target = self.target;
+        let out = builder.json_doc_out(target);
+        t!(fs::create_dir_all(&out));
+        let extra_args = [OsStr::new("--output-format"), OsStr::new("json")];
+        doc_std(builder, DocumentationFormat::JSON, stage, target, &out, &extra_args, &[])
+    }
+}
+
+/// Name of the crates that are visible to consumers of the standard library.
+/// Documentation for internal crates is handled by the rustc step, so internal crates will show
+/// up there.
+///
+/// Order here is important!
+/// Crates need to be processed starting from the leaves, otherwise rustdoc will not
+/// create correct links between crates because rustdoc depends on the
+/// existence of the output directories to know if it should be a local
+/// or remote link.
+const STD_PUBLIC_CRATES: [&str; 5] = ["core", "alloc", "std", "proc_macro", "test"];
+
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+enum DocumentationFormat {
+    HTML,
+    JSON,
+}
+
+impl DocumentationFormat {
+    fn as_str(&self) -> &str {
+        match self {
+            DocumentationFormat::HTML => "HTML",
+            DocumentationFormat::JSON => "JSON",
+        }
+    }
+}
+
+/// Build the documentation for public standard library crates.
+///
+/// `requested_crates` can be used to build only a subset of the crates. If empty, all crates will
+/// be built.
+fn doc_std(
+    builder: &Builder<'_>,
+    format: DocumentationFormat,
+    stage: u32,
+    target: TargetSelection,
+    out: &Path,
+    extra_args: &[&OsStr],
+    requested_crates: &[String],
+) {
+    builder.info(&format!(
+        "Documenting stage{} std ({}) in {} format",
+        stage,
+        target,
+        format.as_str()
+    ));
+    if builder.no_std(target) == Some(true) {
+        panic!(
+            "building std documentation for no_std target {target} is not supported\n\
+             Set `docs = false` in the config to disable documentation."
+        );
+    }
+    let compiler = builder.compiler(stage, builder.config.build);
+    // This is directory where the compiler will place the output of the command.
+    // We will then copy the files from this directory into the final `out` directory, the specified
+    // as a function parameter.
+    let out_dir = builder.stage_out(compiler, Mode::Std).join(target.triple).join("doc");
+    // `cargo` uses the same directory for both JSON docs and HTML docs.
+    // This could lead to cross-contamination when copying files into the specified `out` directory.
+    // For example:
+    // ```bash
+    // x doc std
+    // x doc std --json
+    // ```
+    // could lead to HTML docs being copied into the JSON docs output directory.
+    // To avoid this issue, we clean the doc folder before invoking `cargo`.
+    if out_dir.exists() {
+        builder.remove_dir(&out_dir);
+    }
+
+    let run_cargo_rustdoc_for = |package: &str| {
+        let mut cargo = builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "rustdoc");
+        compile::std_cargo(builder, target, compiler.stage, &mut cargo);
+        cargo
+            .arg("-p")
+            .arg(package)
+            .arg("-Zskip-rustdoc-fingerprint")
+            .arg("--")
+            .arg("-Z")
+            .arg("unstable-options")
+            .arg("--resource-suffix")
+            .arg(&builder.version)
+            .args(extra_args);
+        builder.run(&mut cargo.into());
+    };
+
+    for krate in STD_PUBLIC_CRATES {
+        run_cargo_rustdoc_for(krate);
+        if requested_crates.iter().any(|p| p == krate) {
+            // No need to document more of the libraries if we have the one we want.
+            break;
+        }
+    }
+
+    builder.cp_r(&out_dir, &out);
+}
+
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Rustc {
     pub stage: u32,
@@ -793,7 +881,7 @@ impl Step for ErrorIndex {
         t!(fs::create_dir_all(&out));
         let mut index = tool::ErrorIndex::command(builder);
         index.arg("html");
-        index.arg(out.join("error-index.html"));
+        index.arg(out);
         index.arg(&builder.version);
 
         builder.run(&mut index);
diff --git a/src/bootstrap/download-ci-llvm-stamp b/src/bootstrap/download-ci-llvm-stamp
index 19504a51a584..2e11cf19c3f6 100644
--- a/src/bootstrap/download-ci-llvm-stamp
+++ b/src/bootstrap/download-ci-llvm-stamp
@@ -1,4 +1,4 @@
 Change this file to make users of the `download-ci-llvm` configuration download
 a new version of LLVM from CI, even if the LLVM submodule hasn’t changed.
 
-Last change is for: https://github.com/rust-lang/rust/pull/96867
+Last change is for: https://github.com/rust-lang/rust/pull/97550
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index 789da7481003..802b49d748ac 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -107,6 +107,7 @@ pub enum Subcommand {
     Doc {
         paths: Vec<PathBuf>,
         open: bool,
+        json: bool,
     },
     Test {
         paths: Vec<PathBuf>,
@@ -325,6 +326,11 @@ To learn more about a subcommand, run `./x.py <subcommand> -h`",
             }
             Kind::Doc => {
                 opts.optflag("", "open", "open the docs in a browser");
+                opts.optflag(
+                    "",
+                    "json",
+                    "render the documentation in JSON format in addition to the usual HTML format",
+                );
             }
             Kind::Clean => {
                 opts.optflag("", "all", "clean all build artifacts");
@@ -493,6 +499,7 @@ Arguments:
         ./x.py doc src/doc/book
         ./x.py doc src/doc/nomicon
         ./x.py doc src/doc/book library/std
+        ./x.py doc library/std --json
         ./x.py doc library/std --open
 
     If no arguments are passed then everything is documented:
@@ -581,7 +588,11 @@ Arguments:
                 },
             },
             Kind::Bench => Subcommand::Bench { paths, test_args: matches.opt_strs("test-args") },
-            Kind::Doc => Subcommand::Doc { paths, open: matches.opt_present("open") },
+            Kind::Doc => Subcommand::Doc {
+                paths,
+                open: matches.opt_present("open"),
+                json: matches.opt_present("json"),
+            },
             Kind::Clean => {
                 if !paths.is_empty() {
                     println!("\nclean does not take a path argument\n");
@@ -787,6 +798,13 @@ impl Subcommand {
             _ => false,
         }
     }
+
+    pub fn json(&self) -> bool {
+        match *self {
+            Subcommand::Doc { json, .. } => json,
+            _ => false,
+        }
+    }
 }
 
 fn split(s: &[String]) -> Vec<String> {
diff --git a/src/bootstrap/install.rs b/src/bootstrap/install.rs
index d34aa15c5153..7672b7c91359 100644
--- a/src/bootstrap/install.rs
+++ b/src/bootstrap/install.rs
@@ -200,13 +200,10 @@ install!((self, builder, _config),
         install_sh(builder, "clippy", self.compiler.stage, Some(self.target), &tarball);
     };
     Miri, alias = "miri", Self::should_build(_config), only_hosts: true, {
-        if let Some(tarball) = builder.ensure(dist::Miri { compiler: self.compiler, target: self.target }) {
-            install_sh(builder, "miri", self.compiler.stage, Some(self.target), &tarball);
-        } else {
-            builder.info(
-                &format!("skipping Install miri stage{} ({})", self.compiler.stage, self.target),
-            );
-        }
+        let tarball = builder
+            .ensure(dist::Miri { compiler: self.compiler, target: self.target })
+            .expect("missing miri");
+        install_sh(builder, "miri", self.compiler.stage, Some(self.target), &tarball);
     };
     Rustfmt, alias = "rustfmt", Self::should_build(_config), only_hosts: true, {
         if let Some(tarball) = builder.ensure(dist::Rustfmt {
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 952943b78c6a..c83490316b65 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -112,6 +112,7 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::str;
 
+use config::Target;
 use filetime::FileTime;
 use once_cell::sync::OnceCell;
 
@@ -186,6 +187,9 @@ const LLVM_TOOLS: &[&str] = &[
     "opt",           // used to optimize LLVM bytecode
 ];
 
+/// LLD file names for all flavors.
+const LLD_FILE_NAMES: &[&str] = &["ld.lld", "ld64.lld", "lld-link", "wasm-ld"];
+
 pub const VERSION: usize = 2;
 
 /// Extra --check-cfg to add when building
@@ -194,9 +198,12 @@ const EXTRA_CHECK_CFGS: &[(Option<Mode>, &'static str, Option<&[&'static str]>)]
     (None, "bootstrap", None),
     (Some(Mode::Rustc), "parallel_compiler", None),
     (Some(Mode::ToolRustc), "parallel_compiler", None),
+    (Some(Mode::Codegen), "parallel_compiler", None),
     (Some(Mode::Std), "stdarch_intel_sde", None),
     (Some(Mode::Std), "no_fp_fmt_parse", None),
     (Some(Mode::Std), "no_global_oom_handling", None),
+    (Some(Mode::Std), "no_rc", None),
+    (Some(Mode::Std), "no_sync", None),
     (Some(Mode::Std), "freebsd12", None),
     (Some(Mode::Std), "backtrace_in_libstd", None),
     /* Extra values not defined in the built-in targets yet, but used in std */
@@ -395,13 +402,18 @@ impl Build {
         let src = config.src.clone();
         let out = config.out.clone();
 
+        #[cfg(unix)]
+        // keep this consistent with the equivalent check in x.py:
+        // https://github.com/rust-lang/rust/blob/a8a33cf27166d3eabaffc58ed3799e054af3b0c6/src/bootstrap/bootstrap.py#L796-L797
         let is_sudo = match env::var_os("SUDO_USER") {
-            Some(sudo_user) => match env::var_os("USER") {
-                Some(user) => user != sudo_user,
-                None => false,
-            },
+            Some(_sudo_user) => {
+                let uid = unsafe { libc::getuid() };
+                uid == 0
+            }
             None => false,
         };
+        #[cfg(not(unix))]
+        let is_sudo = false;
 
         let ignore_git = config.ignore_git;
         let rust_info = channel::GitInfo::new(ignore_git, &src);
@@ -447,19 +459,18 @@ impl Build {
             .expect("failed to read src/version");
         let version = version.trim();
 
-        let bootstrap_out = if std::env::var("BOOTSTRAP_PYTHON").is_ok() {
-            out.join("bootstrap").join("debug")
-        } else {
-            let workspace_target_dir = std::env::var("CARGO_TARGET_DIR")
-                .map(PathBuf::from)
-                .unwrap_or_else(|_| src.join("target"));
-            let bootstrap_out = workspace_target_dir.join("debug");
-            if !bootstrap_out.join("rustc").exists() && !cfg!(test) {
-                // this restriction can be lifted whenever https://github.com/rust-lang/rfcs/pull/3028 is implemented
-                panic!("run `cargo build --bins` before `cargo run`")
-            }
-            bootstrap_out
-        };
+        let bootstrap_out = std::env::current_exe()
+            .expect("could not determine path to running process")
+            .parent()
+            .unwrap()
+            .to_path_buf();
+        if !bootstrap_out.join(exe("rustc", config.build)).exists() && !cfg!(test) {
+            // this restriction can be lifted whenever https://github.com/rust-lang/rfcs/pull/3028 is implemented
+            panic!(
+                "`rustc` not found in {}, run `cargo build --bins` before `cargo run`",
+                bootstrap_out.display()
+            )
+        }
 
         let mut build = Build {
             initial_rustc: config.initial_rustc.clone(),
@@ -531,13 +542,8 @@ impl Build {
 
         // Make sure we update these before gathering metadata so we don't get an error about missing
         // Cargo.toml files.
-        let rust_submodules = [
-            "src/tools/rust-installer",
-            "src/tools/cargo",
-            "src/tools/miri",
-            "library/backtrace",
-            "library/stdarch",
-        ];
+        let rust_submodules =
+            ["src/tools/rust-installer", "src/tools/cargo", "library/backtrace", "library/stdarch"];
         for s in rust_submodules {
             build.update_submodule(Path::new(s));
         }
@@ -816,6 +822,11 @@ impl Build {
         self.out.join(&*target.triple).join("doc")
     }
 
+    /// Output directory for all JSON-formatted documentation for a target
+    fn json_doc_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("json-doc")
+    }
+
     fn test_out(&self, target: TargetSelection) -> PathBuf {
         self.out.join(&*target.triple).join("test")
     }
@@ -834,12 +845,13 @@ impl Build {
     ///
     /// If no custom `llvm-config` was specified then Rust's llvm will be used.
     fn is_rust_llvm(&self, target: TargetSelection) -> bool {
-        if self.config.llvm_from_ci && target == self.config.build {
-            return true;
-        }
-
         match self.config.target_config.get(&target) {
-            Some(ref c) => c.llvm_config.is_none(),
+            Some(Target { llvm_has_rust_patches: Some(patched), .. }) => *patched,
+            Some(Target { llvm_config, .. }) => {
+                // If the user set llvm-config we assume Rust is not patched,
+                // but first check to see if it was configured by llvm-from-ci.
+                (self.config.llvm_from_ci && target == self.config.build) || llvm_config.is_none()
+            }
             None => true,
         }
     }
@@ -1297,10 +1309,6 @@ impl Build {
         self.package_vers(&self.version)
     }
 
-    fn llvm_link_tools_dynamically(&self, target: TargetSelection) -> bool {
-        target.contains("linux-gnu") || target.contains("apple-darwin")
-    }
-
     /// Returns the `version` string associated with this compiler for Rust
     /// itself.
     ///
@@ -1629,7 +1637,7 @@ fn chmod(_path: &Path, _perms: u32) {}
 /// If code is not 0 (successful exit status), exit status is 101 (rust's default error code.)
 /// If the test is running and code is an error code, it will cause a panic.
 fn detail_exit(code: i32) -> ! {
-    // if in test and code is an error code, panic with staus code provided
+    // if in test and code is an error code, panic with status code provided
     if cfg!(test) && code != 0 {
         panic!("status code: {}", code);
     } else {
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index e1cc8d671d7f..d6ee6d489cf0 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -423,12 +423,7 @@ impl Step for Llvm {
         // which saves both memory during parallel links and overall disk space
         // for the tools. We don't do this on every platform as it doesn't work
         // equally well everywhere.
-        //
-        // If we're not linking rustc to a dynamic LLVM, though, then don't link
-        // tools to it.
-        let llvm_link_shared =
-            builder.llvm_link_tools_dynamically(target) && builder.llvm_link_shared();
-        if llvm_link_shared {
+        if builder.llvm_link_shared() {
             cfg.define("LLVM_LINK_LLVM_DYLIB", "ON");
         }
 
@@ -553,7 +548,7 @@ impl Step for Llvm {
         // libLLVM.dylib will be built. However, llvm-config will still look
         // for a versioned path like libLLVM-14.dylib. Manually create a symbolic
         // link to make llvm-config happy.
-        if llvm_link_shared && target.contains("apple-darwin") {
+        if builder.llvm_link_shared() && target.contains("apple-darwin") {
             let mut cmd = Command::new(&build_llvm_config);
             let version = output(cmd.arg("--version"));
             let major = version.split('.').next().unwrap();
@@ -638,7 +633,7 @@ fn configure_cmake(
 
         if target.contains("darwin") {
             // Make sure that CMake does not build universal binaries on macOS.
-            // Explicitly specifiy the one single target architecture.
+            // Explicitly specify the one single target architecture.
             if target.starts_with("aarch64") {
                 // macOS uses a different name for building arm64
                 cfg.define("CMAKE_OSX_ARCHITECTURES", "arm64");
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index f1c2a21de59f..01f4cacd771f 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -484,116 +484,103 @@ impl Step for Miri {
         // Except if we are at stage 2, the bootstrap loop is complete and we can stick with our current stage.
         let compiler_std = builder.compiler(if stage < 2 { stage + 1 } else { stage }, host);
 
-        let miri =
-            builder.ensure(tool::Miri { compiler, target: self.host, extra_features: Vec::new() });
-        let cargo_miri = builder.ensure(tool::CargoMiri {
-            compiler,
-            target: self.host,
-            extra_features: Vec::new(),
-        });
+        let miri = builder
+            .ensure(tool::Miri { compiler, target: self.host, extra_features: Vec::new() })
+            .expect("in-tree tool");
+        let _cargo_miri = builder
+            .ensure(tool::CargoMiri { compiler, target: self.host, extra_features: Vec::new() })
+            .expect("in-tree tool");
         // The stdlib we need might be at a different stage. And just asking for the
         // sysroot does not seem to populate it, so we do that first.
         builder.ensure(compile::Std::new(compiler_std, host));
         let sysroot = builder.sysroot(compiler_std);
-        if let (Some(miri), Some(_cargo_miri)) = (miri, cargo_miri) {
-            let mut cargo =
-                builder.cargo(compiler, Mode::ToolRustc, SourceType::Submodule, host, "install");
-            cargo.arg("xargo");
-            // Configure `cargo install` path. cargo adds a `bin/`.
-            cargo.env("CARGO_INSTALL_ROOT", &builder.out);
+        let mut cargo =
+            builder.cargo(compiler, Mode::ToolRustc, SourceType::Submodule, host, "install");
+        cargo.arg("xargo");
+        // Configure `cargo install` path. cargo adds a `bin/`.
+        cargo.env("CARGO_INSTALL_ROOT", &builder.out);
 
-            let mut cargo = Command::from(cargo);
-            if !try_run(builder, &mut cargo) {
-                return;
-            }
-
-            // # Run `cargo miri setup`.
-            let mut cargo = tool::prepare_tool_cargo(
-                builder,
-                compiler,
-                Mode::ToolRustc,
-                host,
-                "run",
-                "src/tools/miri/cargo-miri",
-                SourceType::Submodule,
-                &[],
-            );
-            cargo.add_rustc_lib_path(builder, compiler);
-            cargo.arg("--").arg("miri").arg("setup");
-
-            // Tell `cargo miri setup` where to find the sources.
-            cargo.env("XARGO_RUST_SRC", builder.src.join("library"));
-            // Tell it where to find Miri.
-            cargo.env("MIRI", &miri);
-            // Debug things.
-            cargo.env("RUST_BACKTRACE", "1");
-            // Let cargo-miri know where xargo ended up.
-            cargo.env("XARGO_CHECK", builder.out.join("bin").join("xargo-check"));
-
-            let mut cargo = Command::from(cargo);
-            if !try_run(builder, &mut cargo) {
-                return;
-            }
-
-            // # Determine where Miri put its sysroot.
-            // To this end, we run `cargo miri setup --print-sysroot` and capture the output.
-            // (We do this separately from the above so that when the setup actually
-            // happens we get some output.)
-            // We re-use the `cargo` from above.
-            cargo.arg("--print-sysroot");
-
-            // FIXME: Is there a way in which we can re-use the usual `run` helpers?
-            let miri_sysroot = if builder.config.dry_run {
-                String::new()
-            } else {
-                builder.verbose(&format!("running: {:?}", cargo));
-                let out = cargo
-                    .output()
-                    .expect("We already ran `cargo miri setup` before and that worked");
-                assert!(out.status.success(), "`cargo miri setup` returned with non-0 exit code");
-                // Output is "<sysroot>\n".
-                let stdout = String::from_utf8(out.stdout)
-                    .expect("`cargo miri setup` stdout is not valid UTF-8");
-                let sysroot = stdout.trim_end();
-                builder.verbose(&format!("`cargo miri setup --print-sysroot` said: {:?}", sysroot));
-                sysroot.to_owned()
-            };
-
-            // # Run `cargo test`.
-            let mut cargo = tool::prepare_tool_cargo(
-                builder,
-                compiler,
-                Mode::ToolRustc,
-                host,
-                "test",
-                "src/tools/miri",
-                SourceType::Submodule,
-                &[],
-            );
-            cargo.add_rustc_lib_path(builder, compiler);
-
-            // miri tests need to know about the stage sysroot
-            cargo.env("MIRI_SYSROOT", miri_sysroot);
-            cargo.env("MIRI_HOST_SYSROOT", sysroot);
-            cargo.env("RUSTC_LIB_PATH", builder.rustc_libdir(compiler));
-            cargo.env("MIRI", miri);
-            // propagate --bless
-            if builder.config.cmd.bless() {
-                cargo.env("MIRI_BLESS", "Gesundheit");
-            }
-
-            cargo.arg("--").args(builder.config.cmd.test_args());
-
-            let mut cargo = Command::from(cargo);
-            if !try_run(builder, &mut cargo) {
-                return;
-            }
-
-            // # Done!
-            builder.save_toolstate("miri", ToolState::TestPass);
-        } else {
-            eprintln!("failed to test miri: could not build");
+        let mut cargo = Command::from(cargo);
+        if !try_run(builder, &mut cargo) {
+            return;
         }
+
+        // # Run `cargo miri setup`.
+        let mut cargo = tool::prepare_tool_cargo(
+            builder,
+            compiler,
+            Mode::ToolRustc,
+            host,
+            "run",
+            "src/tools/miri/cargo-miri",
+            SourceType::Submodule,
+            &[],
+        );
+        cargo.add_rustc_lib_path(builder, compiler);
+        cargo.arg("--").arg("miri").arg("setup");
+
+        // Tell `cargo miri setup` where to find the sources.
+        cargo.env("MIRI_LIB_SRC", builder.src.join("library"));
+        // Tell it where to find Miri.
+        cargo.env("MIRI", &miri);
+        // Debug things.
+        cargo.env("RUST_BACKTRACE", "1");
+        // Let cargo-miri know where xargo ended up.
+        cargo.env("XARGO_CHECK", builder.out.join("bin").join("xargo-check"));
+
+        let mut cargo = Command::from(cargo);
+        builder.run(&mut cargo);
+
+        // # Determine where Miri put its sysroot.
+        // To this end, we run `cargo miri setup --print-sysroot` and capture the output.
+        // (We do this separately from the above so that when the setup actually
+        // happens we get some output.)
+        // We re-use the `cargo` from above.
+        cargo.arg("--print-sysroot");
+
+        // FIXME: Is there a way in which we can re-use the usual `run` helpers?
+        let miri_sysroot = if builder.config.dry_run {
+            String::new()
+        } else {
+            builder.verbose(&format!("running: {:?}", cargo));
+            let out =
+                cargo.output().expect("We already ran `cargo miri setup` before and that worked");
+            assert!(out.status.success(), "`cargo miri setup` returned with non-0 exit code");
+            // Output is "<sysroot>\n".
+            let stdout = String::from_utf8(out.stdout)
+                .expect("`cargo miri setup` stdout is not valid UTF-8");
+            let sysroot = stdout.trim_end();
+            builder.verbose(&format!("`cargo miri setup --print-sysroot` said: {:?}", sysroot));
+            sysroot.to_owned()
+        };
+
+        // # Run `cargo test`.
+        let mut cargo = tool::prepare_tool_cargo(
+            builder,
+            compiler,
+            Mode::ToolRustc,
+            host,
+            "test",
+            "src/tools/miri",
+            SourceType::Submodule,
+            &[],
+        );
+        cargo.add_rustc_lib_path(builder, compiler);
+
+        // miri tests need to know about the stage sysroot
+        cargo.env("MIRI_SYSROOT", miri_sysroot);
+        cargo.env("MIRI_HOST_SYSROOT", sysroot);
+        cargo.env("RUSTC_LIB_PATH", builder.rustc_libdir(compiler));
+        cargo.env("MIRI", miri);
+        // propagate --bless
+        if builder.config.cmd.bless() {
+            cargo.env("MIRI_BLESS", "Gesundheit");
+        }
+
+        cargo.arg("--").args(builder.config.cmd.test_args());
+
+        let mut cargo = Command::from(cargo);
+        builder.run(&mut cargo);
     }
 }
 
@@ -854,7 +841,10 @@ fn get_browser_ui_test_version_inner(npm: &Path, global: bool) -> Option<String>
         .output()
         .map(|output| String::from_utf8_lossy(&output.stdout).into_owned())
         .unwrap_or(String::new());
-    lines.lines().find_map(|l| l.split(":browser-ui-test@").skip(1).next()).map(|v| v.to_owned())
+    lines
+        .lines()
+        .find_map(|l| l.split(':').nth(1)?.strip_prefix("browser-ui-test@"))
+        .map(|v| v.to_owned())
 }
 
 fn get_browser_ui_test_version(npm: &Path) -> Option<String> {
@@ -1338,6 +1328,8 @@ note: if you're sure you want to do this, please open an issue as to why. In the
             let json_compiler = compiler.with_stage(0);
             cmd.arg("--jsondocck-path")
                 .arg(builder.ensure(tool::JsonDocCk { compiler: json_compiler, target }));
+            cmd.arg("--jsondoclint-path")
+                .arg(builder.ensure(tool::JsonDocLint { compiler: json_compiler, target }));
         }
 
         if mode == "run-make" {
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index c3b04a9bbce3..ff6f7909a5a3 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -376,6 +376,7 @@ bootstrap_tool!(
     ExpandYamlAnchors, "src/tools/expand-yaml-anchors", "expand-yaml-anchors";
     LintDocs, "src/tools/lint-docs", "lint-docs";
     JsonDocCk, "src/tools/jsondocck", "jsondocck";
+    JsonDocLint, "src/tools/jsondoclint", "jsondoclint";
     HtmlChecker, "src/tools/html-checker", "html-checker";
     BumpStage0, "src/tools/bump-stage0", "bump-stage0";
     ReplaceVersionPlaceholder, "src/tools/replace-version-placeholder", "replace-version-placeholder";
@@ -745,14 +746,18 @@ impl Step for RustAnalyzerProcMacroSrv {
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
         let builder = run.builder;
-        run.path("src/tools/rust-analyzer").default_condition(
-            builder.config.extended
-                && builder
-                    .config
-                    .tools
-                    .as_ref()
-                    .map_or(true, |tools| tools.iter().any(|tool| tool == "rust-analyzer")),
-        )
+
+        // Allow building `rust-analyzer-proc-macro-srv` both as part of the `rust-analyzer` and as a stand-alone tool.
+        run.path("src/tools/rust-analyzer")
+            .path("src/tools/rust-analyzer/crates/proc-macro-srv-cli")
+            .default_condition(
+                builder.config.extended
+                    && builder.config.tools.as_ref().map_or(true, |tools| {
+                        tools.iter().any(|tool| {
+                            tool == "rust-analyzer" || tool == "rust-analyzer-proc-macro-srv"
+                        })
+                    }),
+            )
     }
 
     fn make_run(run: RunConfig<'_>) {
@@ -763,7 +768,7 @@ impl Step for RustAnalyzerProcMacroSrv {
     }
 
     fn run(self, builder: &Builder<'_>) -> Option<PathBuf> {
-        builder.ensure(ToolBuild {
+        let path = builder.ensure(ToolBuild {
             compiler: self.compiler,
             target: self.target,
             tool: "rust-analyzer-proc-macro-srv",
@@ -772,7 +777,15 @@ impl Step for RustAnalyzerProcMacroSrv {
             extra_features: vec!["proc-macro-srv/sysroot-abi".to_owned()],
             is_optional_tool: false,
             source_type: SourceType::InTree,
-        })
+        })?;
+
+        // Copy `rust-analyzer-proc-macro-srv` to `<sysroot>/libexec/`
+        // so that r-a can use it.
+        let libexec_path = builder.sysroot(self.compiler).join("libexec");
+        t!(fs::create_dir_all(&libexec_path));
+        builder.copy(&path, &libexec_path.join("rust-analyzer-proc-macro-srv"));
+
+        Some(path)
     }
 }
 
@@ -855,8 +868,8 @@ tool_extended!((self, builder),
     Cargofmt, "src/tools/rustfmt", "cargo-fmt", stable=true, in_tree=true, {};
     CargoClippy, "src/tools/clippy", "cargo-clippy", stable=true, in_tree=true, {};
     Clippy, "src/tools/clippy", "clippy-driver", stable=true, in_tree=true, {};
-    Miri, "src/tools/miri", "miri", stable=false, {};
-    CargoMiri, "src/tools/miri/cargo-miri", "cargo-miri", stable=false, {};
+    Miri, "src/tools/miri", "miri", stable=false, in_tree=true, {};
+    CargoMiri, "src/tools/miri/cargo-miri", "cargo-miri", stable=false, in_tree=true, {};
     Rls, "src/tools/rls", "rls", stable=true, {};
     // FIXME: tool_std is not quite right, we shouldn't allow nightly features.
     // But `builder.cargo` doesn't know how to handle ToolBootstrap in stages other than 0,
diff --git a/src/bootstrap/toolstate.rs b/src/bootstrap/toolstate.rs
index f3a6759ab846..1a1774432275 100644
--- a/src/bootstrap/toolstate.rs
+++ b/src/bootstrap/toolstate.rs
@@ -77,7 +77,6 @@ static STABLE_TOOLS: &[(&str, &str)] = &[
 // though, as otherwise we will be unable to file an issue if they start
 // failing.
 static NIGHTLY_TOOLS: &[(&str, &str)] = &[
-    ("miri", "src/tools/miri"),
     ("embedded-book", "src/doc/embedded-book"),
     // ("rustc-dev-guide", "src/doc/rustc-dev-guide"),
 ];
diff --git a/src/bootstrap/util.rs b/src/bootstrap/util.rs
index 3a00e258e00e..0ebabbd5ca5c 100644
--- a/src/bootstrap/util.rs
+++ b/src/bootstrap/util.rs
@@ -197,9 +197,11 @@ pub fn symlink_dir(config: &Config, src: &Path, dest: &Path) -> io::Result<()> {
                 ptr::null_mut(),
             );
 
-            let mut data = [0u8; MAXIMUM_REPARSE_DATA_BUFFER_SIZE as usize];
-            let db = data.as_mut_ptr() as *mut REPARSE_MOUNTPOINT_DATA_BUFFER;
-            let buf = &mut (*db).ReparseTarget as *mut u16;
+            #[repr(C, align(8))]
+            struct Align8<T>(T);
+            let mut data = Align8([0u8; MAXIMUM_REPARSE_DATA_BUFFER_SIZE as usize]);
+            let db = data.0.as_mut_ptr() as *mut REPARSE_MOUNTPOINT_DATA_BUFFER;
+            let buf = core::ptr::addr_of_mut!((*db).ReparseTarget) as *mut u16;
             let mut i = 0;
             // FIXME: this conversion is very hacky
             let v = br"\??\";
@@ -219,7 +221,7 @@ pub fn symlink_dir(config: &Config, src: &Path, dest: &Path) -> io::Result<()> {
             let res = DeviceIoControl(
                 h as *mut _,
                 FSCTL_SET_REPARSE_POINT,
-                data.as_ptr() as *mut _,
+                db.cast(),
                 (*db).ReparseDataLength + 8,
                 ptr::null_mut(),
                 0,
diff --git a/src/ci/docker/host-x86_64/arm-android/Dockerfile b/src/ci/docker/host-x86_64/arm-android/Dockerfile
index d0d367b39b49..7a875c960e13 100644
--- a/src/ci/docker/host-x86_64/arm-android/Dockerfile
+++ b/src/ci/docker/host-x86_64/arm-android/Dockerfile
@@ -1,5 +1,6 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 COPY scripts/android-base-apt-get.sh /scripts/
 RUN sh /scripts/android-base-apt-get.sh
 
@@ -13,7 +14,7 @@ RUN dpkg --add-architecture i386 && \
   libgl1-mesa-glx \
   libpulse0 \
   libstdc++6:i386 \
-  openjdk-9-jre-headless \
+  openjdk-8-jre-headless \
   tzdata \
   wget \
   python3
@@ -29,20 +30,12 @@ ENV PATH=$PATH:/android/sdk/platform-tools
 
 ENV TARGETS=arm-linux-androideabi
 
-# We are intentionally allowing an old toolchain on this builder (and that's
-# incompatible with LLVM downloads today).
-ENV NO_DOWNLOAD_CI_LLVM 1
-
-ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/arm-14 \
-    --set llvm.allow-old-toolchain
+ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/arm-14
 
 ENV SCRIPT python3 ../x.py --stage 2 test --host='' --target $TARGETS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
 COPY scripts/android-start-emulator.sh /scripts/
 ENTRYPOINT ["/scripts/android-start-emulator.sh"]
diff --git a/src/ci/docker/host-x86_64/dist-android/Dockerfile b/src/ci/docker/host-x86_64/dist-android/Dockerfile
index c98fa496d486..2328db4ab8b1 100644
--- a/src/ci/docker/host-x86_64/dist-android/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-android/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
 COPY scripts/android-base-apt-get.sh /scripts/
 RUN sh /scripts/android-base-apt-get.sh
@@ -32,13 +32,9 @@ ENV RUST_CONFIGURE_ARGS \
       --i686-linux-android-ndk=/android/ndk/x86-14 \
       --aarch64-linux-android-ndk=/android/ndk/arm64-21 \
       --x86_64-linux-android-ndk=/android/ndk/x86_64-21 \
-      --disable-docs \
-      --set llvm.allow-old-toolchain
+      --disable-docs
 
 ENV SCRIPT python3 ../x.py dist --host='' --target $TARGETS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
-
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
index 973c43072bf4..b960239807af 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
@@ -82,7 +82,7 @@ ENV RUST_CONFIGURE_ARGS \
 ENV SCRIPT ../src/ci/pgo.sh python3 ../x.py dist \
     --host $HOSTS --target $HOSTS \
     --include-default-paths \
-    build-manifest
+    build-manifest bootstrap
 ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=clang
 
 # This is the only builder which will create source tarballs
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh b/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
index 1025f5bce802..fa780e1e45ea 100755
--- a/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
+++ b/src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
@@ -4,7 +4,7 @@ set -ex
 
 source shared.sh
 
-LLVM=llvmorg-14.0.5
+LLVM=llvmorg-15.0.0
 
 mkdir llvm-project
 cd llvm-project
diff --git a/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile b/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile
index 71ea13071bd1..dd74726f8569 100644
--- a/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile
+++ b/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile
@@ -1,5 +1,6 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++-multilib \
   make \
@@ -20,18 +21,10 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
 RUN mkdir -p /config
 RUN echo "[rust]" > /config/nopt-std-config.toml
 RUN echo "optimize = false" >> /config/nopt-std-config.toml
 
-# We are intentionally allowing an old toolchain on this builder (and that's
-# incompatible with LLVM downloads today).
-ENV NO_DOWNLOAD_CI_LLVM 1
-
-ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu --disable-optimize-tests \
-    --set llvm.allow-old-toolchain
+ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu --disable-optimize-tests
 ENV SCRIPT python3 ../x.py test --stage 0 --config /config/nopt-std-config.toml library/std \
   && python3 ../x.py --stage 2 test
diff --git a/src/ci/docker/host-x86_64/i686-gnu/Dockerfile b/src/ci/docker/host-x86_64/i686-gnu/Dockerfile
index ebeab3dbdb79..0c36cfd66bde 100644
--- a/src/ci/docker/host-x86_64/i686-gnu/Dockerfile
+++ b/src/ci/docker/host-x86_64/i686-gnu/Dockerfile
@@ -1,5 +1,6 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++-multilib \
   make \
@@ -20,14 +21,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
-# We are intentionally allowing an old toolchain on this builder (and that's
-# incompatible with LLVM downloads today).
-ENV NO_DOWNLOAD_CI_LLVM 1
-ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu \
-    --set llvm.allow-old-toolchain
+ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu
 # Exclude some tests that are unlikely to be platform specific, to speed up
 # this slow job.
 ENV SCRIPT python3 ../x.py --stage 2 test \
diff --git a/src/ci/docker/host-x86_64/mingw-check/Dockerfile b/src/ci/docker/host-x86_64/mingw-check/Dockerfile
index c6723d91c8bb..52a7776153da 100644
--- a/src/ci/docker/host-x86_64/mingw-check/Dockerfile
+++ b/src/ci/docker/host-x86_64/mingw-check/Dockerfile
@@ -45,7 +45,8 @@ ENV SCRIPT python3 ../x.py --stage 2 test src/tools/expand-yaml-anchors && \
            python3 ../x.py test --stage 0 src/tools/compiletest && \
            python3 ../x.py test --stage 2 src/tools/tidy && \
            python3 ../x.py test --stage 0 core alloc std test proc_macro && \
-           python3 ../x.py doc --stage 0 library/test && \
+           # Build both public and internal documentation.
+           RUSTDOCFLAGS="--document-private-items" python3 ../x.py doc --stage 0 library/test && \
            /scripts/validate-toolstate.sh && \
            /scripts/validate-error-codes.sh && \
            reuse lint && \
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile
index 321b3d6ace48..d55d5b56ad3f 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile
@@ -1,5 +1,6 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
   make \
@@ -23,13 +24,5 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
-# We are intentionally allowing an old toolchain on this builder (and that's
-# incompatible with LLVM downloads today).
-ENV NO_DOWNLOAD_CI_LLVM 1
-
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu \
-    --set llvm.allow-old-toolchain
+ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu
 ENV RUST_CHECK_TARGET check-aux
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
index be4def85f14c..80a004501a81 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
@@ -1,5 +1,6 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
   make \
@@ -19,14 +20,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
-# We are intentionally allowing an old toolchain on this builder (and that's
-# incompatible with LLVM downloads today).
+# We are disabling CI LLVM since distcheck is an offline build.
 ENV NO_DOWNLOAD_CI_LLVM 1
 
-ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --set rust.ignore-git=false \
-    --set llvm.allow-old-toolchain
+ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --set rust.ignore-git=false
 ENV SCRIPT python3 ../x.py --stage 2 test distcheck
 ENV DIST_SRC 1
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile
index e2ec4f275001..4350ca205862 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile
@@ -1,5 +1,6 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
   make \
@@ -27,6 +28,7 @@ RUN apt-get install -y \
   libdbus-1-3 \
   libexpat1 \
   libfontconfig1 \
+  libgbm1 \
   libgcc1 \
   libgconf-2-4 \
   libgdk-pixbuf2.0-0 \
@@ -59,13 +61,10 @@ RUN apt-get install -y \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
 COPY host-x86_64/x86_64-gnu-tools/checktools.sh /tmp/
 
-RUN curl -sL https://nodejs.org/dist/v14.4.0/node-v14.4.0-linux-x64.tar.xz | tar -xJ
-ENV NODE_FOLDER=/node-v14.4.0-linux-x64/bin
+RUN curl -sL https://nodejs.org/dist/v14.20.0/node-v14.20.0-linux-x64.tar.xz | tar -xJ
+ENV NODE_FOLDER=/node-v14.20.0-linux-x64/bin
 ENV PATH="$NODE_FOLDER:${PATH}"
 
 COPY host-x86_64/x86_64-gnu-tools/browser-ui-test.version /tmp/
@@ -80,14 +79,10 @@ COPY host-x86_64/x86_64-gnu-tools/browser-ui-test.version /tmp/
 # the local version of the package is different than the one used by the CI.
 RUN npm install -g browser-ui-test@$(head -n 1 /tmp/browser-ui-test.version) --unsafe-perm=true
 
-# We are intentionally allowing an old toolchain on this builder (and that's
-# incompatible with LLVM downloads today).
-ENV NO_DOWNLOAD_CI_LLVM 1
-
 ENV RUST_CONFIGURE_ARGS \
-  --set llvm.allow-old-toolchain \
   --build=x86_64-unknown-linux-gnu \
   --save-toolstates=/tmp/toolstate/toolstates.json
 
 ENV SCRIPT /tmp/checktools.sh ../x.py && \
-  NODE_PATH=`npm root -g` python3 ../x.py test src/test/rustdoc-gui --stage 2
+  NODE_PATH=`npm root -g` python3 ../x.py test src/test/rustdoc-gui --stage 2 \
+    --test-args "'--no-sandbox --jobs 1'"
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version b/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version
index bae256fd5b38..142464bf22b4 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-tools/browser-ui-test.version
@@ -1 +1 @@
-0.9.7
\ No newline at end of file
+0.11.0
\ No newline at end of file
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh b/src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh
index 0fb8f41a7ec6..cf00c285b0a6 100755
--- a/src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh
@@ -14,7 +14,6 @@ python3 "$X_PY" test --stage 2 --no-fail-fast \
     src/doc/rust-by-example \
     src/doc/embedded-book \
     src/doc/edition-guide \
-    src/tools/miri \
 
 set -e
 
@@ -23,3 +22,4 @@ cat /tmp/toolstate/toolstates.json
 python3 "$X_PY" test --stage 2 check-tools
 python3 "$X_PY" test --stage 2 src/tools/clippy
 python3 "$X_PY" test --stage 2 src/tools/rustfmt
+python3 "$X_PY" test --stage 2 src/tools/miri
diff --git a/src/ci/docker/scripts/android-base-apt-get.sh b/src/ci/docker/scripts/android-base-apt-get.sh
index f1761f80643b..22e2e243e430 100644
--- a/src/ci/docker/scripts/android-base-apt-get.sh
+++ b/src/ci/docker/scripts/android-base-apt-get.sh
@@ -10,6 +10,7 @@ apt-get install -y --no-install-recommends \
   g++ \
   git \
   libssl-dev \
+  libncurses5 \
   make \
   ninja-build \
   pkg-config \
diff --git a/src/ci/github-actions/ci.yml b/src/ci/github-actions/ci.yml
index 6e4b0b0c2c3f..9f4017799008 100644
--- a/src/ci/github-actions/ci.yml
+++ b/src/ci/github-actions/ci.yml
@@ -264,6 +264,9 @@ on:
     branches:
       - "**"
 
+permissions:
+  contents: read
+
 defaults:
   run:
     # On Linux, macOS, and Windows, use the system-provided bash as the default
@@ -273,6 +276,8 @@ defaults:
 
 jobs:
   pr:
+    permissions:
+      actions: write # for rust-lang/simpleinfra/github-actions/cancel-outdated-builds
     <<: *base-ci-job
     name: PR
     env:
@@ -286,13 +291,15 @@ jobs:
 
           - name: x86_64-gnu-llvm-13
             <<: *job-linux-xl
-            
+
           - name: x86_64-gnu-tools
             env:
               CI_ONLY_WHEN_SUBMODULES_CHANGED: 1
             <<: *job-linux-xl
 
   auto:
+    permissions:
+      actions: write # for rust-lang/simpleinfra/github-actions/cancel-outdated-builds
     <<: *base-ci-job
     name: auto
     env:
@@ -455,7 +462,7 @@ jobs:
 
           - name: dist-x86_64-apple
             env:
-              SCRIPT: ./x.py dist --host=x86_64-apple-darwin --target=x86_64-apple-darwin
+              SCRIPT: ./x.py dist bootstrap --include-default-paths --host=x86_64-apple-darwin --target=x86_64-apple-darwin
               RUST_CONFIGURE_ARGS: --enable-full-tools --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               MACOSX_DEPLOYMENT_TARGET: 10.7
@@ -467,7 +474,7 @@ jobs:
 
           - name: dist-apple-various
             env:
-              SCRIPT: ./x.py dist --host='' --target=aarch64-apple-ios,x86_64-apple-ios,aarch64-apple-ios-sim
+              SCRIPT: ./x.py dist bootstrap --include-default-paths --host='' --target=aarch64-apple-ios,x86_64-apple-ios,aarch64-apple-ios-sim
               RUST_CONFIGURE_ARGS: --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               MACOSX_DEPLOYMENT_TARGET: 10.7
@@ -478,7 +485,7 @@ jobs:
 
           - name: dist-x86_64-apple-alt
             env:
-              SCRIPT: ./x.py dist
+              SCRIPT: ./x.py dist bootstrap --include-default-paths
               RUST_CONFIGURE_ARGS: --enable-extended --enable-profiler --set rust.jemalloc --set llvm.ninja=false
               RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
               MACOSX_DEPLOYMENT_TARGET: 10.7
@@ -508,7 +515,7 @@ jobs:
           # This target only needs to support 11.0 and up as nothing else supports the hardware
           - name: dist-aarch64-apple
             env:
-              SCRIPT: ./x.py dist --stage 2
+              SCRIPT: ./x.py dist bootstrap --include-default-paths --stage 2
               RUST_CONFIGURE_ARGS: >-
                 --build=x86_64-apple-darwin
                 --host=aarch64-apple-darwin
@@ -652,7 +659,7 @@ jobs:
                 --target=x86_64-pc-windows-msvc
                 --enable-full-tools
                 --enable-profiler
-              SCRIPT: PGO_HOST=x86_64-pc-windows-msvc src/ci/pgo.sh python x.py dist
+              SCRIPT: PGO_HOST=x86_64-pc-windows-msvc src/ci/pgo.sh python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             <<: *job-windows-xl
 
@@ -664,7 +671,7 @@ jobs:
                 --target=i686-pc-windows-msvc,i586-pc-windows-msvc
                 --enable-full-tools
                 --enable-profiler
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             <<: *job-windows-xl
 
@@ -675,7 +682,7 @@ jobs:
                 --host=aarch64-pc-windows-msvc
                 --enable-full-tools
                 --enable-profiler
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
               # Hack around this SDK version, because it doesn't work with clang.
               # See https://github.com/rust-lang/rust/issues/88796
@@ -692,14 +699,14 @@ jobs:
               # We are intentionally allowing an old toolchain on this builder (and that's
               # incompatible with LLVM downloads today).
               NO_DOWNLOAD_CI_LLVM: 1
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               CUSTOM_MINGW: 1
               DIST_REQUIRE_ALL_TOOLS: 1
             <<: *job-windows-xl
 
           - name: dist-x86_64-mingw
             env:
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
               RUST_CONFIGURE_ARGS: >-
                 --build=x86_64-pc-windows-gnu
                 --enable-full-tools
@@ -715,10 +722,12 @@ jobs:
           - name: dist-x86_64-msvc-alt
             env:
               RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-extended --enable-profiler
-              SCRIPT: python x.py dist
+              SCRIPT: python x.py dist bootstrap --include-default-paths
             <<: *job-windows-xl
 
   try:
+    permissions:
+      actions: write # for rust-lang/simpleinfra/github-actions/cancel-outdated-builds
     <<: *base-ci-job
     name: try
     env:
diff --git a/src/doc/book b/src/doc/book
index 0a5421ceb238..f1e5ad844d0c 160000
--- a/src/doc/book
+++ b/src/doc/book
@@ -1 +1 @@
-Subproject commit 0a5421ceb238357b3634fb75234eba4d1dad643c
+Subproject commit f1e5ad844d0c61738006cdef26227beeb136948e
diff --git a/src/doc/embedded-book b/src/doc/embedded-book
index befe68408743..4ce51cb7441a 160000
--- a/src/doc/embedded-book
+++ b/src/doc/embedded-book
@@ -1 +1 @@
-Subproject commit befe6840874311635c417cf731377f07234ee373
+Subproject commit 4ce51cb7441a6f02b5bf9b07b2eb755c21ab7954
diff --git a/src/doc/index.md b/src/doc/index.md
index b77790e33b70..744c7f709a6d 100644
--- a/src/doc/index.md
+++ b/src/doc/index.md
@@ -101,7 +101,7 @@ accomplishing various tasks.
 
 Many of Rust's errors come with error codes, and you can request extended
 diagnostics from the compiler on those errors. You can also [read them
-here](error-index.html), if you prefer to read them that way.
+here](error_codes/index.html), if you prefer to read them that way.
 
 # Master Rust
 
diff --git a/src/doc/nomicon b/src/doc/nomicon
index d880e6ac2acf..f53bfa056929 160000
--- a/src/doc/nomicon
+++ b/src/doc/nomicon
@@ -1 +1 @@
-Subproject commit d880e6ac2acf133dce640da24b9fb692844f02d4
+Subproject commit f53bfa056929217870a5d2df1366d2e7ba35096d
diff --git a/src/doc/reference b/src/doc/reference
index f62e93c28323..a7cdac33ca73 160000
--- a/src/doc/reference
+++ b/src/doc/reference
@@ -1 +1 @@
-Subproject commit f62e93c28323ed9637d0a205a0c256498674a509
+Subproject commit a7cdac33ca7356ad49d5c2b5e2c5010889b33eee
diff --git a/src/doc/rust-by-example b/src/doc/rust-by-example
index 03301f8ae55f..767a6bd9727a 160000
--- a/src/doc/rust-by-example
+++ b/src/doc/rust-by-example
@@ -1 +1 @@
-Subproject commit 03301f8ae55fa6f20f7ea152a517598e6db2cdb7
+Subproject commit 767a6bd9727a596d7cfdbaeee475e65b2670ea3a
diff --git a/src/doc/rustc-dev-guide b/src/doc/rustc-dev-guide
index 04892c1a6fc1..f587d6e7cdde 160000
--- a/src/doc/rustc-dev-guide
+++ b/src/doc/rustc-dev-guide
@@ -1 +1 @@
-Subproject commit 04892c1a6fc145602ac7367945fda9d4ee83c9fb
+Subproject commit f587d6e7cddeaa3cf0a33ec1e368df1a408fa0aa
diff --git a/src/doc/rustc/src/SUMMARY.md b/src/doc/rustc/src/SUMMARY.md
index 4e6bc41daa71..06883ddd58bc 100644
--- a/src/doc/rustc/src/SUMMARY.md
+++ b/src/doc/rustc/src/SUMMARY.md
@@ -18,10 +18,13 @@
     - [aarch64-apple-ios-sim](platform-support/aarch64-apple-ios-sim.md)
     - [\*-apple-watchos\*](platform-support/apple-watchos.md)
     - [aarch64-nintendo-switch-freestanding](platform-support/aarch64-nintendo-switch-freestanding.md)
+    - [armeb-unknown-linux-gnueabi](platform-support/armeb-unknown-linux-gnueabi.md)
     - [armv4t-none-eabi](platform-support/armv4t-none-eabi.md)
+    - [armv5te-none-eabi](platform-support/armv5te-none-eabi.md)
     - [armv6k-nintendo-3ds](platform-support/armv6k-nintendo-3ds.md)
     - [armv7-unknown-linux-uclibceabi](platform-support/armv7-unknown-linux-uclibceabi.md)
     - [armv7-unknown-linux-uclibceabihf](platform-support/armv7-unknown-linux-uclibceabihf.md)
+    - [\*-android and \*-androideabi](platform-support/android.md)
     - [\*-fuchsia](platform-support/fuchsia.md)
     - [\*-kmc-solid_\*](platform-support/kmc-solid.md)
     - [m68k-unknown-linux-gnu](platform-support/m68k-unknown-linux-gnu.md)
@@ -32,6 +35,7 @@
     - [*-unknown-openbsd](platform-support/openbsd.md)
     - [\*-unknown-uefi](platform-support/unknown-uefi.md)
     - [wasm64-unknown-unknown](platform-support/wasm64-unknown-unknown.md)
+    - [x86_64-fortanix-unknown-sgx](platform-support/x86_64-fortanix-unknown-sgx.md)
     - [x86_64-unknown-none](platform-support/x86_64-unknown-none.md)
 - [Targets](targets/index.md)
     - [Built-in Targets](targets/built-in.md)
diff --git a/src/doc/rustc/src/command-line-arguments.md b/src/doc/rustc/src/command-line-arguments.md
index f05ff3f1b6b4..79cdfb82e417 100644
--- a/src/doc/rustc/src/command-line-arguments.md
+++ b/src/doc/rustc/src/command-line-arguments.md
@@ -270,6 +270,11 @@ This flag will set which lints should be set to the [warn level](lints/levels.md
 
 _Note:_ The order of these lint level arguments is taken into account, see [lint level via compiler flag](lints/levels.md#via-compiler-flag) for more information.
 
+<a id="option-force-warn"></a>
+## `--force-warn`: force a lint to warn
+
+This flag sets the given lint to the [forced warn level](lints/levels.md#force-warn) and the level cannot be overridden, even ignoring the [lint caps](lints/levels.md#capping-lints).
+
 <a id="option-a-allow"></a>
 ## `-A`: set lint allowed
 
@@ -381,6 +386,12 @@ are:
 - `always` — Always use colors.
 - `never` — Never colorize output.
 
+<a id="option-diagnostic-width"></a>
+## `--diagnostic-width`: specify the terminal width for diagnostics
+
+This flag takes a number that specifies the width of the terminal in characters.
+Formatting of diagnostics will take the width into consideration to make them better fit on the screen.
+
 <a id="option-remap-path-prefix"></a>
 ## `--remap-path-prefix`: remap source names in output
 
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 742fbe11d9c6..ea2792c218bb 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -125,17 +125,17 @@ target | std | notes
 `aarch64-apple-ios` | ✓ | ARM64 iOS
 [`aarch64-apple-ios-sim`](platform-support/aarch64-apple-ios-sim.md) | ✓ | Apple iOS Simulator on ARM64
 `aarch64-fuchsia` | ✓ | ARM64 Fuchsia
-`aarch64-linux-android` | ✓ | ARM64 Android
+[`aarch64-linux-android`](platform-support/android.md) | ✓ | ARM64 Android
 `aarch64-unknown-none-softfloat` | * | Bare ARM64, softfloat
 `aarch64-unknown-none` | * | Bare ARM64, hardfloat
-`arm-linux-androideabi` | ✓ | ARMv7 Android
+[`arm-linux-androideabi`](platform-support/android.md) | ✓ | ARMv7 Android
 `arm-unknown-linux-musleabi` | ✓ | ARMv6 Linux with MUSL
 `arm-unknown-linux-musleabihf` | ✓ | ARMv6 Linux with MUSL, hardfloat
 `armebv7r-none-eabi` | * | Bare ARMv7-R, Big Endian
 `armebv7r-none-eabihf` | * | Bare ARMv7-R, Big Endian, hardfloat
 `armv5te-unknown-linux-gnueabi` | ✓ | ARMv5TE Linux (kernel 4.4, glibc 2.23)
 `armv5te-unknown-linux-musleabi` | ✓ | ARMv5TE Linux with MUSL
-`armv7-linux-androideabi` | ✓ | ARMv7a Android
+[`armv7-linux-androideabi`](platform-support/android.md) | ✓ | ARMv7a Android
 `armv7-unknown-linux-gnueabi` | ✓ |ARMv7 Linux (kernel 4.15, glibc 2.27)
 `armv7-unknown-linux-musleabi` | ✓ |ARMv7 Linux with MUSL
 `armv7-unknown-linux-musleabihf` | ✓ | ARMv7 Linux with MUSL, hardfloat
@@ -146,7 +146,7 @@ target | std | notes
 `i586-pc-windows-msvc` | * | 32-bit Windows w/o SSE
 `i586-unknown-linux-gnu` | ✓ | 32-bit Linux w/o SSE (kernel 4.4, glibc 2.23)
 `i586-unknown-linux-musl` | ✓ | 32-bit Linux w/o SSE, MUSL
-`i686-linux-android` | ✓ | 32-bit x86 Android
+[`i686-linux-android`](platform-support/android.md) | ✓ | 32-bit x86 Android
 `i686-unknown-freebsd` | ✓ | 32-bit FreeBSD
 `i686-unknown-linux-musl` | ✓ | 32-bit Linux with MUSL
 `mips-unknown-linux-musl` | ✓ | MIPS Linux with MUSL
@@ -165,7 +165,7 @@ target | std | notes
 `thumbv7em-none-eabi` | * | Bare Cortex-M4, M7
 `thumbv7em-none-eabihf` | * | Bare Cortex-M4F, M7F, FPU, hardfloat
 `thumbv7m-none-eabi` | * | Bare Cortex-M3
-`thumbv7neon-linux-androideabi` | ✓ | Thumb2-mode ARMv7a Android with NEON
+[`thumbv7neon-linux-androideabi`](platform-support/android.md) | ✓ | Thumb2-mode ARMv7a Android with NEON
 `thumbv7neon-unknown-linux-gnueabihf` | ✓ | Thumb2-mode ARMv7a Linux with NEON (kernel 4.4, glibc 2.23)
 `thumbv8m.base-none-eabi` | * | ARMv8-M Baseline
 `thumbv8m.main-none-eabi` | * | ARMv8-M Mainline
@@ -174,9 +174,9 @@ target | std | notes
 `wasm32-unknown-unknown` | ✓ | WebAssembly
 `wasm32-wasi` | ✓ | WebAssembly with WASI
 `x86_64-apple-ios` | ✓ | 64-bit x86 iOS
-`x86_64-fortanix-unknown-sgx` | ✓ | [Fortanix ABI] for 64-bit Intel SGX
+[`x86_64-fortanix-unknown-sgx`](platform-support/x86_64-fortanix-unknown-sgx.md) | ✓ | [Fortanix ABI] for 64-bit Intel SGX
 `x86_64-fuchsia` | ✓ | 64-bit Fuchsia
-`x86_64-linux-android` | ✓ | 64-bit x86 Android
+[`x86_64-linux-android`](platform-support/android.md) | ✓ | 64-bit x86 Android
 `x86_64-pc-solaris` | ✓ | 64-bit Solaris 10/11, illumos
 `x86_64-unknown-linux-gnux32` | ✓ | 64-bit Linux (x32 ABI) (kernel 4.15, glibc 2.27)
 [`x86_64-unknown-none`](platform-support/x86_64-unknown-none.md) | * | Freestanding/bare-metal x86_64, softfloat
@@ -213,7 +213,7 @@ target | std | host | notes
 [`aarch64-pc-windows-gnullvm`](platform-support/pc-windows-gnullvm.md) | ✓ | ✓ |
 `aarch64-unknown-freebsd` | ✓ | ✓ | ARM64 FreeBSD
 `aarch64-unknown-hermit` | ✓ |  | ARM64 HermitCore
-`aarch64-unknown-uefi` | * |  | ARM64 UEFI
+[`aarch64-unknown-uefi`](platform-support/unknown-uefi.md) | * |  | ARM64 UEFI
 `aarch64-unknown-linux-gnu_ilp32` | ✓ | ✓ | ARM64 Linux (ILP32 ABI)
 `aarch64-unknown-netbsd` | ✓ | ✓ |
 [`aarch64-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | ARM64 OpenBSD
@@ -223,8 +223,10 @@ target | std | host | notes
 `aarch64_be-unknown-linux-gnu_ilp32` | ✓ | ✓ | ARM64 Linux (big-endian, ILP32 ABI)
 `aarch64_be-unknown-linux-gnu` | ✓ | ✓ | ARM64 Linux (big-endian)
 [`arm64_32-apple-watchos`](platform-support/apple-watchos.md) | ✓ | | ARM Apple WatchOS 64-bit with 32-bit pointers
+[`armeb-unknown-linux-gnueabi`](platform-support/armeb-unknown-linux-gnueabi.md) | ✓ | ? | ARM BE8 the default ARM big-endian architecture since [ARMv6](https://developer.arm.com/documentation/101754/0616/armlink-Reference/armlink-Command-line-Options/--be8?lang=en).
 `armv4t-none-eabi` | * |  | ARMv4T A32
 `armv4t-unknown-linux-gnueabi` | ? |  |
+[`armv5te-none-eabi`](platform-support/armv5te-none-eabi.md) | * | | ARMv5TE A32
 `armv5te-unknown-linux-uclibceabi` | ? |  | ARMv5TE Linux with uClibc
 `armv6-unknown-freebsd` | ✓ | ✓ | ARMv6 FreeBSD
 `armv6-unknown-netbsd-eabihf` | ? |  |
@@ -250,7 +252,7 @@ target | std | host | notes
 `i686-unknown-haiku` | ✓ | ✓ | 32-bit Haiku
 `i686-unknown-netbsd` | ✓ | ✓ | NetBSD/i386 with SSE2
 [`i686-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 32-bit OpenBSD
-`i686-unknown-uefi` | * |  | 32-bit UEFI
+[`i686-unknown-uefi`](platform-support/unknown-uefi.md) | * |  | 32-bit UEFI
 `i686-uwp-windows-gnu` | ? |  |
 `i686-uwp-windows-msvc` | ? |  |
 `i686-wrs-vxworks` | ? |  |
@@ -291,6 +293,7 @@ target | std | host | notes
 `sparc64-unknown-netbsd` | ✓ | ✓ | NetBSD/sparc64
 [`sparc64-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | OpenBSD/sparc64
 `thumbv4t-none-eabi` | * |  | ARMv4T T32
+[`thumbv5te-none-eabi`](platform-support/armv5te-none-eabi.md) | * | | ARMv5TE T32
 `thumbv7a-pc-windows-msvc` | ? |  |
 `thumbv7a-uwp-windows-msvc` | ✓ |  |
 `thumbv7neon-unknown-linux-musleabihf` | ? |  | Thumb2-mode ARMv7a Linux with NEON, MUSL
@@ -307,7 +310,7 @@ target | std | host | notes
 `x86_64-unknown-l4re-uclibc` | ? |  |
 `x86_64-unknown-none-linuxkernel` | * |  | Linux kernel modules
 [`x86_64-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 64-bit OpenBSD
-`x86_64-unknown-uefi` | * |  | 64-bit UEFI
+[`x86_64-unknown-uefi`](platform-support/unknown-uefi.md) | * |  | 64-bit UEFI
 `x86_64-uwp-windows-gnu` | ✓ |  |
 `x86_64-uwp-windows-msvc` | ✓ |  |
 `x86_64-wrs-vxworks` | ? |  |
diff --git a/src/doc/rustc/src/platform-support/android.md b/src/doc/rustc/src/platform-support/android.md
new file mode 100644
index 000000000000..b2c8e5d4df73
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/android.md
@@ -0,0 +1,45 @@
+# *-linux-android and *-linux-androideabi
+
+**Tier: 2**
+
+[Android] is a mobile operating system built on top of the Linux kernel.
+
+[Android]: https://source.android.com/
+
+## Target maintainers
+
+- Chris Wailes ([@chriswailes](https://github.com/chriswailes))
+- Matthew Maurer ([@maurer](https://github.com/maurer))
+- Martin Geisler ([@mgeisler](https://github.com/mgeisler))
+
+## Requirements
+
+This target is cross-compiled from a host environment. Development may be done
+from the [source tree] or using the Android NDK.
+
+[source tree]: https://source.android.com/docs/setup/build/downloading
+
+Android targets support std. Generated binaries use the ELF file format.
+
+## NDK/API Update Policy
+
+Rust will support the most recent Long Term Support (LTS) Android Native
+Development Kit (NDK).  By default Rust will support all API levels supported
+by the NDK, but a higher minimum API level may be required if deemed necessary.
+
+## Building the target
+
+To build Rust binaries for Android you'll need a copy of the most recent LTS
+edition of the [Android NDK].  Supported Android targets are:
+
+* aarch64-linux-android
+* arm-linux-androideabi
+* armv7-linux-androideabi
+* i686-linux-android
+* thumbv7neon-linux-androideabi
+* x86_64-linux-android
+
+[Android NDK]: https://developer.android.com/ndk/downloads
+
+A list of all supported targets can be found
+[here](https://doc.rust-lang.org/rustc/platform-support.html)
diff --git a/src/doc/rustc/src/platform-support/armeb-unknown-linux-gnueabi.md b/src/doc/rustc/src/platform-support/armeb-unknown-linux-gnueabi.md
new file mode 100644
index 000000000000..507631cdc540
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/armeb-unknown-linux-gnueabi.md
@@ -0,0 +1,74 @@
+# armeb-unknown-linux-gnueabi
+**Tier: 3**
+
+Target for cross-compiling Linux user-mode applications targetting the ARM BE8 architecture.
+
+## Overview
+BE8 architecture retains the same little-endian ordered code-stream used by conventional little endian ARM systems, however the data accesses are in big-endian. BE8 is used primarily in high-performance networking applications where the ability to read packets in their native "Network Byte Order" is important (many network protocols transmit data in big-endian byte order for their wire formats).
+
+## History
+BE8 architecture is the default big-endian architecture for ARM since [ARMv6](https://developer.arm.com/documentation/101754/0616/armlink-Reference/armlink-Command-line-Options/--be8?lang=en). It's predecessor, used for ARMv4 and ARMv5 devices was [BE32](https://developer.arm.com/documentation/dui0474/j/linker-command-line-options/--be32). On ARMv6 architecture, endianness can be configured via [system registers](https://developer.arm.com/documentation/ddi0290/g/unaligned-and-mixed-endian-data-access-support/mixed-endian-access-support/interaction-between-the-bus-protocol-and-the-core-endianness). However, BE32 was withdrawn for [ARMv7](https://developer.arm.com/documentation/ddi0406/cb/Appendixes/Deprecated-and-Obsolete-Features/Obsolete-features/Support-for-BE-32-endianness-model) onwards.
+
+## Target Maintainers
+* [@WorksButNotTested](https://github.com/WorksButNotTested)
+
+## Requirements
+The target is cross-compiled. This target supports `std` in the normal way (indeed only nominal changes are required from the standard ARM configuration).
+
+## Target definition
+The target definition can be seen [here](https://github.com/rust-lang/rust/tree/master/compiler/rustc_target/src/spec/armeb_unknown_linux_gnueabi.rs). In particular, it should be noted that the `features` specify that this target is built for the ARMv8 core. Though this can likely be modified as required.
+
+## Building the target
+Because it is Tier 3, rust does not yet ship pre-compiled artifacts for this target.
+
+Therefore, you can build Rust with support for the target by adding it to the target list in config.toml, a sample configuration is shown below. It is expected that the user already have a working GNU compiler toolchain and update the paths accordingly.
+
+```toml
+[llvm]
+download-ci-llvm = false
+skip-rebuild = true
+optimize = true
+ninja = true
+targets = "ARM;X86"
+clang = false
+
+[build]
+target = ["x86_64-unknown-linux-gnu", "armeb-unknown-linux-gnueabi"]
+docs = false
+docs-minification = false
+compiler-docs = false
+[install]
+prefix = "/home/user/x-tools/rust/"
+
+[rust]
+debug-logging=true
+backtrace = true
+incremental = true
+
+[target.x86_64-unknown-linux-gnu]
+
+[dist]
+
+[target.armeb-unknown-linux-gnueabi]
+cc = "/home/user/x-tools/armeb-unknown-linux-gnueabi/bin/armeb-unknown-linux-gnueabi-gcc"
+cxx = "/home/user/x-tools/armeb-unknown-linux-gnueabi/bin/armeb-unknown-linux-gnueabi-g++"
+ar = "/home/user/x-tools/armeb-unknown-linux-gnueabi/bin/armeb-unknown-linux-gnueabi-ar"
+ranlib = "/home/user/x-tools/armeb-unknown-linux-gnueabi/bin/armeb-unknown-linux-gnueabi-ranlib"
+linker = "/home/user/x-tools/armeb-unknown-linux-gnueabi/bin/armeb-unknown-linux-gnueabi-gcc"
+llvm-config = "/home/user/x-tools/clang/bin/llvm-config"
+llvm-filecheck = "/home/user/x-tools/clang/bin/FileCheck"
+```
+
+## Building Rust programs
+
+The following `.cargo/config` is needed inside any project directory to build for the BE8 target:
+
+```toml
+[build]
+target = "armeb-unknown-linux-gnueabi"
+
+[target.armeb-unknown-linux-gnueabi]
+linker = "armeb-unknown-linux-gnueabi-gcc"
+```
+
+Note that it is expected that the user has a suitable linker from the GNU toolchain.
diff --git a/src/doc/rustc/src/platform-support/armv4t_none_eabi.md b/src/doc/rustc/src/platform-support/armv4t-none-eabi.md
similarity index 100%
rename from src/doc/rustc/src/platform-support/armv4t_none_eabi.md
rename to src/doc/rustc/src/platform-support/armv4t-none-eabi.md
diff --git a/src/doc/rustc/src/platform-support/armv5te-none-eabi.md b/src/doc/rustc/src/platform-support/armv5te-none-eabi.md
new file mode 100644
index 000000000000..f469dab1c42f
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/armv5te-none-eabi.md
@@ -0,0 +1,66 @@
+# `armv5te-none-eabi`
+
+**Tier: 3**
+
+Bare-metal target for any cpu in the ARMv5TE architecture family, supporting
+ARM/Thumb code interworking (aka `a32`/`t32`), with `a32` code as the default code
+generation.
+
+The `thumbv5te-none-eabi` target is the same as this one, but the instruction set defaults to `t32`.
+
+## Target Maintainers
+
+* [@QuinnPainter](https://github.com/QuinnPainter)
+
+## Requirements
+
+The target is cross-compiled, and uses static linking.
+
+By default, the `lld` linker included with Rust will be used.
+
+However, you may want to use the `arm-none-eabi-ld` linker instead. This can be obtained for Windows/Mac/Linux from the [ARM
+Developer Website][arm-dev], or possibly from your OS's package manager. To use it, add the following to your `.cargo/config.toml`:
+
+```toml
+[target.armv5te-none-eabi]
+linker = "arm-none-eabi-ld"
+```
+
+[arm-dev]: https://developer.arm.com/Tools%20and%20Software/GNU%20Toolchain
+
+This target doesn't provide a linker script, you'll need to bring your own
+according to the specific device you want to target. Pass
+`-Clink-arg=-Tyour_script.ld` as a rustc argument to make the linker use
+`your_script.ld` during linking.
+
+## Building Rust Programs
+
+Because it is Tier 3, rust does not yet ship pre-compiled artifacts for this target.
+
+Just use the `build-std` nightly cargo feature to build the `core` library. You
+can pass this as a command line argument to cargo, or your `.cargo/config.toml`
+file might include the following lines:
+
+```toml
+[unstable]
+build-std = ["core"]
+```
+
+Most of `core` should work as expected, with the following notes:
+* the target is "soft float", so `f32` and `f64` operations are emulated in
+  software.
+* integer division is also emulated in software.
+* the target is old enough that it doesn't have atomic instructions.
+
+`alloc` is also supported, as long as you provide your own global allocator.
+
+Rust programs are output as ELF files.
+
+## Testing
+
+This is a cross-compiled target that you will need to emulate during testing.
+
+Because this is a device-agnostic target, and the exact emulator that you'll
+need depends on the specific device you want to run your code on.
+
+For example, when programming for the DS, you can use one of the several available DS emulators, such as [melonDS](https://melonds.kuribo64.net/).
diff --git a/src/doc/rustc/src/platform-support/fuchsia.md b/src/doc/rustc/src/platform-support/fuchsia.md
index c2a1613f288c..1ff6003c121c 100644
--- a/src/doc/rustc/src/platform-support/fuchsia.md
+++ b/src/doc/rustc/src/platform-support/fuchsia.md
@@ -42,6 +42,11 @@ authoritative if this occurs. Instead of pinging individual members, use
 1. [Testing](#testing)
     1. [Running unit tests](#running-unit-tests)
     1. [Running the compiler test suite](#running-the-compiler-test-suite)
+1. [Debugging](#debugging)
+    1. [`zxdb`](#zxdb)
+    1. [Attaching `zxdb`](#attaching-zxdb)
+    1. [Using `zxdb`](#using-zxdb)
+    1. [Displaying source code in `zxdb`](#displaying-source-code-in-zxdb)
 
 ## Requirements
 
@@ -79,7 +84,7 @@ the following commands:
 
 ```sh
 rustup target add x86_64-fuchsia
-rustup target add aarch_64-fuchsia
+rustup target add aarch64-fuchsia
 ```
 
 After installing our Fuchsia targets, we can now compile a Rust binary that targets
@@ -125,13 +130,20 @@ during compilation:
 [target.x86_64-fuchsia]
 
 rustflags = [
-    "-Lnative", "<SDK_PATH>/arch/x64/sysroot/lib",
-    "-Lnative", "<SDK_PATH>/arch/x64/lib"
+    "-Lnative=<SDK_PATH>/arch/x64/lib",
+    "-Lnative=<SDK_PATH>/arch/x64/sysroot/lib"
 ]
 ```
 
 *Note: Make sure to fill out `<SDK_PATH>` with the path to the downloaded [Fuchsia SDK].*
 
+These options configure the following:
+
+* `-Lnative=${SDK_PATH}/arch/${ARCH}/lib`: Link against Fuchsia libraries from
+  the SDK
+* `-Lnative=${SDK_PATH}/arch/${ARCH}/sysroot/lib`: Link against Fuchsia sysroot
+  libraries from the SDK
+
 In total, our new project will look like:
 
 **Current directory structure**
@@ -246,7 +258,7 @@ the following options:
   platform of your choice
 * `-Lnative ${SDK_PATH}/arch/${ARCH}/lib`: Link against Fuchsia libraries from
   the SDK
-* `-Lnative ${SDK_PATH}/arch/${ARCH}/sysroot/lib`: Link against Fuchsia kernel
+* `-Lnative ${SDK_PATH}/arch/${ARCH}/sysroot/lib`: Link against Fuchsia sysroot
   libraries from the SDK
 
 Putting it all together:
@@ -323,10 +335,18 @@ Now, create the following files inside:
 The `package` file describes our package's name and version number. Every
 package must contain one.
 
-**`pkg/hello_fuchsia.manifest`**
+**`pkg/hello_fuchsia.manifest` if using cargo**
 ```txt
-bin/hello_fuchsia=target/x86_64-fuchsia/debug/hello_fuchsia     # If using cargo...
-bin/hello_fuchsia=bin/hello_fuchsia                             # If using rustc...
+bin/hello_fuchsia=target/x86_64-fuchsia/debug/hello_fuchsia
+lib/ld.so.1=<SDK_PATH>/arch/x64/sysroot/dist/lib/ld.so.1
+lib/libfdio.so=<SDK_PATH>/arch/x64/dist/libfdio.so
+meta/package=pkg/meta/package
+meta/hello_fuchsia.cm=pkg/meta/hello_fuchsia.cm
+```
+
+**`pkg/hello_fuchsia.manifest` if using rustc**
+```txt
+bin/hello_fuchsia=bin/hello_fuchsia
 lib/ld.so.1=<SDK_PATH>/arch/x64/sysroot/dist/lib/ld.so.1
 lib/libfdio.so=<SDK_PATH>/arch/x64/dist/libfdio.so
 meta/package=pkg/meta/package
@@ -368,6 +388,7 @@ language called CML. The Fuchsia devsite contains an [overview of CML] and a
 }
 ```
 
+**Current directory structure**
 ```txt
 hello_fuchsia/
 ┗━ pkg/
@@ -386,6 +407,9 @@ ${SDK_PATH}/tools/${ARCH}/cmc compile \
     -o pkg/meta/hello_fuchsia.cm
 ```
 
+*Note: `--includepath` tells the compiler where to look for `include`s from our CML.
+In our case, we're only using `syslog/client.shard.cml`.*
+
 **Current directory structure**
 ```txt
 hello_fuchsia/
@@ -397,19 +421,17 @@ hello_fuchsia/
    ┗━ hello_fuchsia.cml
 ```
 
-*Note: `--includepath` tells the compiler where to look for `include`s from our CML.
-In our case, we're only using `syslog/client.shard.cml`.*
-
 ### Building a Fuchsia package
 
 Next, we'll build a package manifest as defined by our manifest:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/pm \
-    -o hello_fuchsia_manifest \
+    -api-level $(${SDK_PATH}/tools/${ARCH}/ffx version -v | grep "api-level" | head -1 |  awk -F ' ' '{print $2}') \
+    -o pkg/hello_fuchsia_manifest \
     -m pkg/hello_fuchsia.manifest \
     build \
-    -output-package-manifest hello_fuchsia_package_manifest
+    -output-package-manifest pkg/hello_fuchsia_package_manifest
 ```
 
 This will produce `pkg/hello_fuchsia_manifest/` which is a package manifest we can
@@ -469,15 +491,15 @@ We can publish our new package to that repository with:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/pm publish \
-    -repo repo \
-    -lp -f <(echo "hello_fuchsia_package_manifest")
+    -repo pkg/repo \
+    -lp -f <(echo "pkg/hello_fuchsia_package_manifest")
 ```
 
 Then we can add the repository to `ffx`'s package server as `hello-fuchsia` using:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/ffx repository add-from-pm \
-    repo \
+    pkg/repo \
     -r hello-fuchsia
 ```
 
@@ -554,6 +576,7 @@ Finally, run the component:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/ffx component run \
+    /core/ffx-laboratory:hello_fuchsia \
     fuchsia-pkg://hello-fuchsia/hello_fuchsia_manifest#meta/hello_fuchsia.cm
 ```
 
@@ -563,6 +586,7 @@ passed.
 ```sh
 ${SDK_PATH}/tools/${ARCH}/ffx component run \
     --recreate \
+    /core/ffx-laboratory:hello_fuchsia \
     fuchsia-pkg://hello-fuchsia/hello_fuchsia_manifest#meta/hello_fuchsia.cm
 ```
 
@@ -620,6 +644,130 @@ available on the [Fuchsia devsite].
 Running the Rust test suite on Fuchsia is [not currently supported], but work is
 underway to enable it.
 
+## Debugging
+
+### `zxdb`
+
+Debugging components running on a Fuchsia emulator can be done using the
+console-mode debugger: [zxdb]. We will demonstrate attaching necessary symbol
+paths to debug our `hello-fuchsia` component.
+
+### Attaching `zxdb`
+
+In a separate terminal, issue the following command from our `hello_fuchsia`
+directory to launch `zxdb`:
+
+**In separate terminal**
+```sh
+${SDK_PATH}/tools/${ARCH}/ffx debug connect -- \
+    --symbol-path target/x86_64-fuchsia/debug
+```
+
+* `--symbol-path` gets required symbol paths, which are
+necessary for stepping through your program.
+
+The "[displaying source code in `zxdb`](#displaying-source-code-in-zxdb)" section describes how you can
+display Rust and/or Fuchsia source code in your debugging session.
+
+### Using `zxdb`
+
+Once launched, you will be presented with the window:
+
+```sh
+Connecting (use "disconnect" to cancel)...
+Connected successfully.
+👉 To get started, try "status" or "help".
+[zxdb]
+```
+
+To attach to our program, we can run:
+
+```sh
+[zxdb] attach hello_fuchsia
+```
+
+**Expected output**
+```sh
+Waiting for process matching "hello_fuchsia".
+Type "filter" to see the current filters.
+```
+
+Next, we can create a breakpoint at main using "b main":
+
+```sh
+[zxdb] b main
+```
+
+**Expected output**
+```sh
+Created Breakpoint 1 @ main
+```
+
+Finally, we can re-run the "hello_fuchsia" component from our original
+terminal:
+
+```sh
+${SDK_PATH}/tools/${ARCH}/ffx component run \
+    --recreate \
+    fuchsia-pkg://hello-fuchsia/hello_fuchsia_manifest#meta/hello_fuchsia.cm
+```
+
+Once our component is running, our `zxdb` window will stop execution
+in our main as desired:
+
+**Expected output**
+```txt
+Breakpoint 1 now matching 1 addrs for main
+🛑 on bp 1 hello_fuchsia::main() • main.rs:2
+   1 fn main() {
+ ▶ 2     println!("Hello Fuchsia!");
+   3 }
+   4
+[zxdb]
+```
+
+`zxdb` has similar commands to other debuggers like [gdb].
+To list the available commands, run "help" in the
+`zxdb` window or visit [the zxdb documentation].
+
+```sh
+[zxdb] help
+```
+
+**Expected output**
+```sh
+Help!
+
+  Type "help <command>" for command-specific help.
+
+Other help topics (see "help <topic>")
+...
+```
+
+### Displaying source code in `zxdb`
+
+By default, the debugger will not be able to display
+source code while debugging. For our user code, we displayed
+source code by pointing our debugger to our debug binary via
+the `--symbol-path` arg. To display library source code in
+the debugger, you must provide paths to the source using
+`--build-dir`. For example, to display the Rust and Fuchsia
+source code:
+
+```sh
+${SDK_PATH}/tools/${ARCH}/ffx debug connect -- \
+    --symbol-path target/x86_64-fuchsia/debug \
+    --build-dir ${RUST_SRC_PATH}/rust \
+    --build-dir ${FUCHSIA_SRC_PATH}/fuchsia/out/default
+```
+
+ * `--build-dir` links against source code paths, which
+ are not strictly necessary for debugging, but is a nice-to-have
+ for displaying source code in `zxdb`.
+
+ Linking to a Fuchsia checkout can help with debugging Fuchsia libraries,
+ such as [fdio].
+
 [Fuchsia team]: https://team-api.infra.rust-lang.org/v1/teams/fuchsia.json
 [Fuchsia]: https://fuchsia.dev/
 [source tree]: https://fuchsia.dev/fuchsia-src/get-started/learn/build
@@ -630,3 +778,7 @@ underway to enable it.
 [reference for the file format]: https://fuchsia.dev/reference/cml
 [Fuchsia devsite]: https://fuchsia.dev/reference/cml
 [not currently supported]: https://fxbug.dev/105393
+[zxdb]: https://fuchsia.dev/fuchsia-src/development/debugger
+[gdb]: https://www.sourceware.org/gdb/
+[the zxdb documentation]: https://fuchsia.dev/fuchsia-src/development/debugger
+[fdio]: https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/lib/fdio/
diff --git a/src/doc/rustc/src/platform-support/m68k-unknown-linux-gnu.md b/src/doc/rustc/src/platform-support/m68k-unknown-linux-gnu.md
index d325ba3346ab..b18a125f3b09 100644
--- a/src/doc/rustc/src/platform-support/m68k-unknown-linux-gnu.md
+++ b/src/doc/rustc/src/platform-support/m68k-unknown-linux-gnu.md
@@ -87,7 +87,7 @@ Rust programs can be built for that target:
 rustc --target m68k-unknown-linux-gnu your-code.rs
 ```
 
-Very simple progams can be run using the `qemu-m68k-static` program:
+Very simple programs can be run using the `qemu-m68k-static` program:
 
 ```text
 $ qemu-m68k-static your-code
diff --git a/src/doc/rustc/src/platform-support/pc-windows-gnullvm.md b/src/doc/rustc/src/platform-support/pc-windows-gnullvm.md
index 721c234c6e60..fb0cea05d440 100644
--- a/src/doc/rustc/src/platform-support/pc-windows-gnullvm.md
+++ b/src/doc/rustc/src/platform-support/pc-windows-gnullvm.md
@@ -25,7 +25,7 @@ Like with any other Windows target created binaries are in PE format.
 
 ## Building the target
 
-For cross-compilation I recommend using [llvm-mingw](https://github.com/mstorsjo/llvm-mingw) toolchain, one change that seems necessary beside configuring corss compilers is disabling experimental `m86k` target. Otherwise LLVM build fails with `multiple definition ...` errors.
+For cross-compilation I recommend using [llvm-mingw](https://github.com/mstorsjo/llvm-mingw) toolchain, one change that seems necessary beside configuring cross compilers is disabling experimental `m86k` target. Otherwise LLVM build fails with `multiple definition ...` errors.
 Native bootstrapping builds require rather fragile hacks until host artifacts are available so I won't describe them here.
 
 ## Building Rust programs
diff --git a/src/doc/rustc/src/platform-support/unknown-uefi.md b/src/doc/rustc/src/platform-support/unknown-uefi.md
index 8f90d9c7453d..295dec0f0e48 100644
--- a/src/doc/rustc/src/platform-support/unknown-uefi.md
+++ b/src/doc/rustc/src/platform-support/unknown-uefi.md
@@ -133,7 +133,7 @@ There are 3 common ways to compile native C code for UEFI targets:
 - Use native Windows targets. This means compiling your C code for the Windows
   platform as if it was the UEFI platform. This works for static libraries, but
   needs adjustments when linking into an UEFI executable. You can, however,
-  link such static libraries seemlessly into rust code compiled for UEFI
+  link such static libraries seamlessly into rust code compiled for UEFI
   targets. Be wary of any includes that are not specifically suitable for UEFI
   targets (especially the C standard library includes are not always
   compatible). Freestanding compilations are recommended to avoid
diff --git a/src/doc/rustc/src/platform-support/wasm64-unknown-unknown.md b/src/doc/rustc/src/platform-support/wasm64-unknown-unknown.md
index 021b904debd8..6932e6a5764b 100644
--- a/src/doc/rustc/src/platform-support/wasm64-unknown-unknown.md
+++ b/src/doc/rustc/src/platform-support/wasm64-unknown-unknown.md
@@ -30,7 +30,7 @@ is 8-bytes large as well as pointers. The tradeoff, though, is that the maximum
 memory size is now the full 64-bit address space instead of the 4GB as limited
 by the 32-bit address space for `wasm32-unknown-unknown`.
 
-This target is not a stable target. The [memory64] WebAssembly proposal is stil
+This target is not a stable target. The [memory64] WebAssembly proposal is still
 in-progress and not standardized. This means that there are not many engines
 which implement the `memory64` feature and if they do they're likely behind a
 flag, for example:
diff --git a/src/doc/rustc/src/platform-support/x86_64-fortanix-unknown-sgx.md b/src/doc/rustc/src/platform-support/x86_64-fortanix-unknown-sgx.md
new file mode 100644
index 000000000000..97b5827c1443
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/x86_64-fortanix-unknown-sgx.md
@@ -0,0 +1,72 @@
+# `x86_64-fortanix-unknown-sgx`
+
+**Tier: 2**
+
+Secure enclaves using [Intel Software Guard Extensions
+(SGX)](https://www.intel.com/content/www/us/en/developer/tools/software-guard-extensions/overview.html)
+based on the ABI defined by Fortanix for the [Enclave Development Platform
+(EDP)](https://edp.fortanix.com/).
+
+## Target maintainers
+
+The [EDP team](mailto:edp.maintainers@fortanix.com) at Fortanix.
+
+- Jethro Beekman [@jethrogb](https://github.com/jethrogb)
+- Raoul Strackx [@raoulstrackx](https://github.com/raoulstrackx)
+- Mohsen Zohrevandi [@mzohreva](https://github.com/mzohreva)
+
+## Requirements
+
+The target supports `std` with a default allocator. Only cross compilation is
+supported.
+
+Binaries support all CPUs that include Intel SGX. Only 64-bit mode is supported.
+
+Not all `std` features are supported, see [Using Rust's
+std](https://edp.fortanix.com/docs/concepts/rust-std/) for details.
+
+The `extern "C"` calling convention is the System V AMD64 ABI.
+
+The supported ABI is the
+[fortanix-sgx-abi](https://edp.fortanix.com/docs/api/fortanix_sgx_abi/index.html).
+
+The compiler output is ELF, but the native format for the platform is the SGX
+stream (SGXS) format. A converter like
+[ftxsgx-elf2sgxs](https://crates.io/crates/fortanix-sgx-tools) is needed.
+
+Programs in SGXS format adhering to the Fortanix SGX ABI can be run with any
+compatible runner, such as
+[ftxsgx-runner](https://crates.io/crates/fortanix-sgx-tools).
+
+See the [EDP installation
+guide](https://edp.fortanix.com/docs/installation/guide/) for recommendations
+on how to setup a development and runtime environment.
+
+## Building the target
+
+As a tier 2 target, the target is built by the Rust project.
+
+You can configure rustbuild like so:
+
+```toml
+[build]
+build-stage = 1
+target = ["x86_64-fortanix-unknown-sgx"]
+```
+
+## Building Rust programs
+
+Standard build flows using `cargo` or `rustc` should work.
+
+## Testing
+
+The Rust test suite as well as custom unit and integration tests will run on
+hardware that has Intel SGX enabled if a cargo runner is configured correctly,
+see the requirements section.
+
+## Cross-compilation toolchains and C code
+
+C code is not generally supported, as there is no libc. C code compiled for
+x86-64 in freestanding mode using the System V AMD64 ABI may work. The
+[rs-libc](https://crates.io/crates/rs-libc) crate contains a subset of libc
+that's known to work with this target.
diff --git a/src/doc/unstable-book/src/compiler-flags/check-cfg.md b/src/doc/unstable-book/src/compiler-flags/check-cfg.md
index bfa92e7d32a8..321992f7b0d7 100644
--- a/src/doc/unstable-book/src/compiler-flags/check-cfg.md
+++ b/src/doc/unstable-book/src/compiler-flags/check-cfg.md
@@ -143,7 +143,7 @@ fn do_features() {}
 
 #[cfg(has_feathers = "zapping")] // This is expected as "has_feathers" was provided in names()
                                  // and because no value checking was enable for "has_feathers"
-                                 // no warning is emited for the value "zapping"
+                                 // no warning is emitted for the value "zapping"
 fn do_zapping() {}
 
 #[cfg(has_mumble_frotz)]    // This is UNEXPECTED because names checking is enable and
diff --git a/src/doc/unstable-book/src/compiler-flags/remap-cwd-prefix.md b/src/doc/unstable-book/src/compiler-flags/remap-cwd-prefix.md
index 977d258529f8..3890a12b7e68 100644
--- a/src/doc/unstable-book/src/compiler-flags/remap-cwd-prefix.md
+++ b/src/doc/unstable-book/src/compiler-flags/remap-cwd-prefix.md
@@ -8,7 +8,7 @@ This flag will rewrite absolute paths under the current working directory,
 replacing the current working directory prefix with a specified value.
 
 The given value may be absolute or relative, or empty. This switch takes
-precidence over `--remap-path-prefix` in case they would both match a given
+precedence over `--remap-path-prefix` in case they would both match a given
 path.
 
 This flag helps to produce deterministic output, by removing the current working
diff --git a/src/doc/unstable-book/src/compiler-flags/self-profile-events.md b/src/doc/unstable-book/src/compiler-flags/self-profile-events.md
index 3ce18743be50..3e644f786f67 100644
--- a/src/doc/unstable-book/src/compiler-flags/self-profile-events.md
+++ b/src/doc/unstable-book/src/compiler-flags/self-profile-events.md
@@ -41,7 +41,7 @@ $ rustc -Zself-profile -Zself-profile-events=default,args
 
 - `llvm`
   - Adds tracing information about LLVM passes and codegeneration.
-  - Disabled by default because this only works when `-Znew-llvm-pass-manager` is enabled.
+  - Disabled by default because this significantly increases the trace file size.
 
 ## Event synonyms
 
diff --git a/src/doc/unstable-book/src/language-features/raw-dylib.md b/src/doc/unstable-book/src/language-features/raw-dylib.md
index 23fc5b3052d8..5fd208ae7571 100644
--- a/src/doc/unstable-book/src/language-features/raw-dylib.md
+++ b/src/doc/unstable-book/src/language-features/raw-dylib.md
@@ -26,9 +26,9 @@ fn main() {
 
 ## Limitations
 
-Currently, this feature is only supported on `-windows-msvc` targets.  Non-Windows platforms don't have import
-libraries, and an incompatibility between LLVM and the BFD linker means that it is not currently supported on
-`-windows-gnu` targets.
+This feature is unstable for the `x86` architecture, and stable for all other architectures.
 
-On the `i686-pc-windows-msvc` target, this feature supports only the `cdecl`, `stdcall`, `system`, and `fastcall`
-calling conventions.
+This feature is only supported on Windows.
+
+On the `x86` architecture, this feature supports only the `cdecl`, `stdcall`, `system`, `fastcall`, and
+`vectorcall` calling conventions.
diff --git a/src/doc/unstable-book/src/language-features/unix-sigpipe.md b/src/doc/unstable-book/src/language-features/unix-sigpipe.md
new file mode 100644
index 000000000000..aa39b6eb2886
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/unix-sigpipe.md
@@ -0,0 +1,54 @@
+# `unix_sigpipe`
+
+The tracking issue for this feature is: [#97889]
+
+[#97889]: https://github.com/rust-lang/rust/issues/97889
+
+---
+
+The `#[unix_sigpipe = "..."]` attribute on `fn main()` can be used to specify how libstd shall setup `SIGPIPE` on Unix platforms before invoking `fn main()`. This attribute is ignored on non-Unix targets. There are three variants:
+* `#[unix_sigpipe = "inherit"]`
+* `#[unix_sigpipe = "sig_dfl"]`
+* `#[unix_sigpipe = "sig_ign"]`
+
+## `#[unix_sigpipe = "inherit"]`
+
+Leave `SIGPIPE` untouched before entering `fn main()`. Unless the parent process has changed the default `SIGPIPE` handler from `SIG_DFL` to something else, this will behave the same as `#[unix_sigpipe = "sig_dfl"]`.
+
+## `#[unix_sigpipe = "sig_dfl"]`
+
+Set the `SIGPIPE` handler to `SIG_DFL`. This will result in your program getting killed if it tries to write to a closed pipe. This is normally what you want if your program produces textual output.
+
+### Example
+
+```rust,no_run
+#![feature(unix_sigpipe)]
+#[unix_sigpipe = "sig_dfl"]
+fn main() { loop { println!("hello world"); } }
+```
+
+```bash
+% ./main | head -n 1
+hello world
+```
+
+## `#[unix_sigpipe = "sig_ign"]`
+
+Set the `SIGPIPE` handler to `SIG_IGN` before invoking `fn main()`. This will result in `ErrorKind::BrokenPipe` errors if you program tries to write to a closed pipe. This is normally what you want if you for example write socket servers, socket clients, or pipe peers.
+
+This is what libstd has done by default since 2014. Omitting `#[unix_sigpipe = "..."]` is the same as having `#[unix_sigpipe = "sig_ign"]`.
+
+### Example
+
+```rust,no_run
+#![feature(unix_sigpipe)]
+#[unix_sigpipe = "sig_ign"]
+fn main() { loop { println!("hello world"); } }
+```
+
+```bash
+% ./main | head -n 1
+hello world
+thread 'main' panicked at 'failed printing to stdout: Broken pipe (os error 32)', library/std/src/io/stdio.rs:1016:9
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+```
diff --git a/src/etc/check_missing_items.py b/src/etc/check_missing_items.py
deleted file mode 100644
index 025f320e3a10..000000000000
--- a/src/etc/check_missing_items.py
+++ /dev/null
@@ -1,195 +0,0 @@
-#!/usr/bin/env python
-
-# This test ensures that every ID in the produced json actually resolves to an item either in
-# `index` or `paths`. It DOES NOT check that the structure of the produced json is actually in
-# any way correct, for example an empty map would pass.
-
-# FIXME: Better error output
-
-import sys
-import json
-
-crate = json.load(open(sys.argv[1], encoding="utf-8"))
-
-
-def get_local_item(item_id):
-    if item_id in crate["index"]:
-        return crate["index"][item_id]
-    print("Missing local ID:", item_id)
-    sys.exit(1)
-
-
-# local IDs have to be in `index`, external ones can sometimes be in `index` but otherwise have
-# to be in `paths`
-def valid_id(item_id):
-    return item_id in crate["index"] or item_id[0] != "0" and item_id in crate["paths"]
-
-
-def check_generics(generics):
-    for param in generics["params"]:
-        check_generic_param(param)
-    for where_predicate in generics["where_predicates"]:
-        if "bound_predicate" in where_predicate:
-            pred = where_predicate["bound_predicate"]
-            check_type(pred["type"])
-            for bound in pred["bounds"]:
-                check_generic_bound(bound)
-        elif "region_predicate" in where_predicate:
-            pred = where_predicate["region_predicate"]
-            for bound in pred["bounds"]:
-                check_generic_bound(bound)
-        elif "eq_predicate" in where_predicate:
-            pred = where_predicate["eq_predicate"]
-            check_type(pred["rhs"])
-            check_type(pred["lhs"])
-
-
-def check_generic_param(param):
-    if "type" in param["kind"]:
-        ty = param["kind"]["type"]
-        if ty["default"]:
-            check_type(ty["default"])
-    elif "const" in param["kind"]:
-        check_type(param["kind"]["const"])
-
-
-def check_generic_bound(bound):
-    if "trait_bound" in bound:
-        for param in bound["trait_bound"]["generic_params"]:
-            check_generic_param(param)
-        check_path(bound["trait_bound"]["trait"])
-
-
-def check_decl(decl):
-    for (_name, ty) in decl["inputs"]:
-        check_type(ty)
-    if decl["output"]:
-        check_type(decl["output"])
-
-def check_path(path):
-    args = path["args"]
-    if args:
-        if "angle_bracketed" in args:
-            for arg in args["angle_bracketed"]["args"]:
-                if "type" in arg:
-                    check_type(arg["type"])
-                elif "const" in arg:
-                    check_type(arg["const"]["type"])
-            for binding in args["angle_bracketed"]["bindings"]:
-                if "equality" in binding["binding"]:
-                    term = binding["binding"]["equality"]
-                    if "type" in term: check_type(term["type"])
-                    elif "const" in term: check_type(term["const"])
-                elif "constraint" in binding["binding"]:
-                    for bound in binding["binding"]["constraint"]:
-                        check_generic_bound(bound)
-        elif "parenthesized" in args:
-            for input_ty in args["parenthesized"]["inputs"]:
-                check_type(input_ty)
-            if args["parenthesized"]["output"]:
-                check_type(args["parenthesized"]["output"])
-    if not valid_id(path["id"]):
-        print("Type contained an invalid ID:", path["id"])
-        sys.exit(1)
-
-def check_type(ty):
-    if ty["kind"] == "resolved_path":
-        check_path(ty["inner"])
-    elif ty["kind"] == "tuple":
-        for ty in ty["inner"]:
-            check_type(ty)
-    elif ty["kind"] == "slice":
-        check_type(ty["inner"])
-    elif ty["kind"] == "impl_trait":
-        for bound in ty["inner"]:
-            check_generic_bound(bound)
-    elif ty["kind"] in ("raw_pointer", "borrowed_ref", "array"):
-        check_type(ty["inner"]["type"])
-    elif ty["kind"] == "function_pointer":
-        for param in ty["inner"]["generic_params"]:
-            check_generic_param(param)
-        check_decl(ty["inner"]["decl"])
-    elif ty["kind"] == "qualified_path":
-        check_type(ty["inner"]["self_type"])
-        check_path(ty["inner"]["trait"])
-
-
-work_list = set([crate["root"]])
-visited = work_list.copy()
-
-while work_list:
-    current = work_list.pop()
-    visited.add(current)
-    item = get_local_item(current)
-    # check intradoc links
-    for (_name, link) in item["links"].items():
-        if not valid_id(link):
-            print("Intra-doc link contains invalid ID:", link)
-
-    # check all fields that reference types such as generics as well as nested items
-    # (modules, structs, traits, and enums)
-    if item["kind"] == "module":
-        work_list |= set(item["inner"]["items"]) - visited
-    elif item["kind"] == "struct":
-        check_generics(item["inner"]["generics"])
-        work_list |= (
-            set(item["inner"]["fields"]) | set(item["inner"]["impls"])
-        ) - visited
-    elif item["kind"] == "struct_field":
-        check_type(item["inner"])
-    elif item["kind"] == "enum":
-        check_generics(item["inner"]["generics"])
-        work_list |= (
-            set(item["inner"]["variants"]) | set(item["inner"]["impls"])
-        ) - visited
-    elif item["kind"] == "variant":
-        if item["inner"]["variant_kind"] == "tuple":
-            for ty in item["inner"]["variant_inner"]:
-                check_type(ty)
-        elif item["inner"]["variant_kind"] == "struct":
-            work_list |= set(item["inner"]["variant_inner"]) - visited
-    elif item["kind"] in ("function", "method"):
-        check_generics(item["inner"]["generics"])
-        check_decl(item["inner"]["decl"])
-    elif item["kind"] in ("static", "constant", "assoc_const"):
-        check_type(item["inner"]["type"])
-    elif item["kind"] == "typedef":
-        check_type(item["inner"]["type"])
-        check_generics(item["inner"]["generics"])
-    elif item["kind"] == "opaque_ty":
-        check_generics(item["inner"]["generics"])
-        for bound in item["inner"]["bounds"]:
-            check_generic_bound(bound)
-    elif item["kind"] == "trait_alias":
-        check_generics(item["inner"]["params"])
-        for bound in item["inner"]["bounds"]:
-            check_generic_bound(bound)
-    elif item["kind"] == "trait":
-        check_generics(item["inner"]["generics"])
-        for bound in item["inner"]["bounds"]:
-            check_generic_bound(bound)
-        work_list |= (
-            set(item["inner"]["items"]) | set(item["inner"]["implementations"])
-        ) - visited
-    elif item["kind"] == "impl":
-        check_generics(item["inner"]["generics"])
-        if item["inner"]["trait"]:
-            check_path(item["inner"]["trait"])
-        if item["inner"]["blanket_impl"]:
-            check_type(item["inner"]["blanket_impl"])
-        check_type(item["inner"]["for"])
-        for assoc_item in item["inner"]["items"]:
-            if not valid_id(assoc_item):
-                print("Impl block referenced a missing ID:", assoc_item)
-                sys.exit(1)
-    elif item["kind"] == "assoc_type":
-        for bound in item["inner"]["bounds"]:
-            check_generic_bound(bound)
-        if item["inner"]["default"]:
-            check_type(item["inner"]["default"])
-    elif item["kind"] == "import":
-        if item["inner"]["id"]:
-            inner_id = item["inner"]["id"]
-            assert valid_id(inner_id)
-            if inner_id in crate["index"] and inner_id not in visited:
-                work_list.add(inner_id)
diff --git a/src/etc/cpu-usage-over-time-plot.sh b/src/etc/cpu-usage-over-time-plot.sh
index 1c3425591943..2617378ba5fd 100755
--- a/src/etc/cpu-usage-over-time-plot.sh
+++ b/src/etc/cpu-usage-over-time-plot.sh
@@ -15,7 +15,7 @@
 # Improvements to this script are greatly appreciated!
 
 if [[ $# != 2 ]]; then
-    echo "expected 2 arguments, recieved $#"
+    echo "expected 2 arguments, received $#"
     echo "example usage: './src/etc/cpu-usage-over-time-plot.sh \
 7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c \
 x86_64-gnu'"
diff --git a/src/etc/htmldocck.py b/src/etc/htmldocck.py
index baf95627c702..c97fb4b80547 100644
--- a/src/etc/htmldocck.py
+++ b/src/etc/htmldocck.py
@@ -386,7 +386,7 @@ def check_tree_attr(tree, path, attr, pat, regexp):
     return ret
 
 
-# Returns the number of occurences matching the regex (`regexp`) and the text (`pat`).
+# Returns the number of occurrences matching the regex (`regexp`) and the text (`pat`).
 def check_tree_text(tree, path, pat, regexp, stop_at_first):
     path = normalize_xpath(path)
     match_count = 0
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
index cbdfea89efb8..7bc35c7d5516 100644
--- a/src/librustdoc/Cargo.toml
+++ b/src/librustdoc/Cargo.toml
@@ -10,18 +10,19 @@ path = "lib.rs"
 arrayvec = { version = "0.7", default-features = false }
 askama = { version = "0.11", default-features = false, features = ["config"] }
 atty = "0.2"
-pulldown-cmark = { version = "0.9.2", default-features = false }
-minifier = "0.2.2"
-serde = { version = "1.0", features = ["derive"] }
-serde_json = "1.0"
-smallvec = "1.8.1"
-tempfile = "3"
 itertools = "0.10.1"
+minifier = "0.2.2"
+once_cell = "1.10.0"
+pulldown-cmark = { version = "0.9.2", default-features = false }
 regex = "1"
 rustdoc-json-types = { path = "../rustdoc-json-types" }
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+smallvec = "1.8.1"
+tempfile = "3"
+thin-vec = "0.2.8"
 tracing = "0.1"
 tracing-tree = "0.2.0"
-once_cell = "1.10.0"
 
 [dependencies.tracing-subscriber]
 version = "0.3.3"
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index 756e4f3b127e..175472797cb4 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -123,7 +123,7 @@ where
             kind: Box::new(ImplItem(Box::new(Impl {
                 unsafety: hir::Unsafety::Normal,
                 generics: new_generics,
-                trait_: Some(clean_trait_ref_with_bindings(self.cx, trait_ref, &[])),
+                trait_: Some(clean_trait_ref_with_bindings(self.cx, trait_ref, ThinVec::new())),
                 for_: clean_middle_ty(ty, self.cx, None),
                 items: Vec::new(),
                 polarity,
diff --git a/src/librustdoc/clean/blanket_impl.rs b/src/librustdoc/clean/blanket_impl.rs
index da15c3c2b1fa..fd169f64885c 100644
--- a/src/librustdoc/clean/blanket_impl.rs
+++ b/src/librustdoc/clean/blanket_impl.rs
@@ -2,7 +2,6 @@ use crate::rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtE
 use rustc_hir as hir;
 use rustc_infer::infer::{InferOk, TyCtxtInferExt};
 use rustc_infer::traits;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::ToPredicate;
 use rustc_span::DUMMY_SP;
 
@@ -115,7 +114,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                             ),
                             // FIXME(eddyb) compute both `trait_` and `for_` from
                             // the post-inference `trait_ref`, as it's more accurate.
-                            trait_: Some(clean_trait_ref_with_bindings(cx, trait_ref.0, &[])),
+                            trait_: Some(clean_trait_ref_with_bindings(cx, trait_ref.0, ThinVec::new())),
                             for_: clean_middle_ty(ty.0, cx, None),
                             items: cx.tcx
                                 .associated_items(impl_def_id)
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 31b805f2ed7e..c8aa51c3a49a 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -3,9 +3,10 @@
 use std::iter::once;
 use std::sync::Arc;
 
+use thin_vec::ThinVec;
+
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_data_structures::thin_vec::ThinVec;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::DefId;
@@ -459,7 +460,7 @@ pub(crate) fn build_impl(
         ),
     };
     let polarity = tcx.impl_polarity(did);
-    let trait_ = associated_trait.map(|t| clean_trait_ref_with_bindings(cx, t, &[]));
+    let trait_ = associated_trait.map(|t| clean_trait_ref_with_bindings(cx, t, ThinVec::new()));
     if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
         super::build_deref_target_impls(cx, &trait_items, ret);
     }
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 41f9eb3cdf6b..bd68dffb823d 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -20,7 +20,7 @@ use rustc_hir::PredicateOrigin;
 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
 use rustc_middle::middle::resolve_lifetime as rl;
 use rustc_middle::ty::fold::TypeFolder;
-use rustc_middle::ty::subst::{InternalSubsts, Subst};
+use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, AdtKind, DefIdTree, EarlyBinder, Lift, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_span::hygiene::{AstPass, MacroKind};
@@ -33,7 +33,8 @@ use std::collections::hash_map::Entry;
 use std::collections::BTreeMap;
 use std::default::Default;
 use std::hash::Hash;
-use std::{mem, vec};
+use std::mem;
+use thin_vec::ThinVec;
 
 use crate::core::{self, DocContext, ImplTraitParam};
 use crate::formats::item_type::ItemType;
@@ -49,14 +50,23 @@ pub(crate) fn clean_doc_module<'tcx>(doc: &DocModule<'tcx>, cx: &mut DocContext<
     let mut inserted = FxHashSet::default();
     items.extend(doc.foreigns.iter().map(|(item, renamed)| {
         let item = clean_maybe_renamed_foreign_item(cx, item, *renamed);
-        if let Some(name) = item.name {
+        if let Some(name) = item.name && !item.attrs.lists(sym::doc).has_word(sym::hidden) {
             inserted.insert((item.type_(), name));
         }
         item
     }));
-    items.extend(doc.mods.iter().map(|x| {
-        inserted.insert((ItemType::Module, x.name));
-        clean_doc_module(x, cx)
+    items.extend(doc.mods.iter().filter_map(|x| {
+        if !inserted.insert((ItemType::Module, x.name)) {
+            return None;
+        }
+        let item = clean_doc_module(x, cx);
+        if item.attrs.lists(sym::doc).has_word(sym::hidden) {
+            // Hidden modules are stripped at a later stage.
+            // If a hidden module has the same name as a visible one, we want
+            // to keep both of them around.
+            inserted.remove(&(ItemType::Module, x.name));
+        }
+        Some(item)
     }));
 
     // Split up imports from all other items.
@@ -71,7 +81,7 @@ pub(crate) fn clean_doc_module<'tcx>(doc: &DocModule<'tcx>, cx: &mut DocContext<
         }
         let v = clean_maybe_renamed_item(cx, item, *renamed);
         for item in &v {
-            if let Some(name) = item.name {
+            if let Some(name) = item.name && !item.attrs.lists(sym::doc).has_word(sym::hidden) {
                 inserted.insert((item.type_(), name));
             }
         }
@@ -125,7 +135,7 @@ fn clean_generic_bound<'tcx>(
                 bug!("clean: parenthesized `GenericBound::LangItemTrait`");
             };
 
-            let trait_ = clean_trait_ref_with_bindings(cx, trait_ref, &bindings);
+            let trait_ = clean_trait_ref_with_bindings(cx, trait_ref, bindings);
             GenericBound::TraitBound(
                 PolyTrait { trait_, generic_params: vec![] },
                 hir::TraitBoundModifier::None,
@@ -147,14 +157,14 @@ fn clean_generic_bound<'tcx>(
 pub(crate) fn clean_trait_ref_with_bindings<'tcx>(
     cx: &mut DocContext<'tcx>,
     trait_ref: ty::TraitRef<'tcx>,
-    bindings: &[TypeBinding],
+    bindings: ThinVec<TypeBinding>,
 ) -> Path {
     let kind = cx.tcx.def_kind(trait_ref.def_id).into();
     if !matches!(kind, ItemType::Trait | ItemType::TraitAlias) {
         span_bug!(cx.tcx.def_span(trait_ref.def_id), "`TraitRef` had unexpected kind {:?}", kind);
     }
     inline::record_extern_fqn(cx, trait_ref.def_id, kind);
-    let path = external_path(cx, trait_ref.def_id, true, bindings.to_vec(), trait_ref.substs);
+    let path = external_path(cx, trait_ref.def_id, true, bindings, trait_ref.substs);
 
     debug!("ty::TraitRef\n  subst: {:?}\n", trait_ref.substs);
 
@@ -164,7 +174,7 @@ pub(crate) fn clean_trait_ref_with_bindings<'tcx>(
 fn clean_poly_trait_ref_with_bindings<'tcx>(
     cx: &mut DocContext<'tcx>,
     poly_trait_ref: ty::PolyTraitRef<'tcx>,
-    bindings: &[TypeBinding],
+    bindings: ThinVec<TypeBinding>,
 ) -> GenericBound {
     let poly_trait_ref = poly_trait_ref.lift_to_tcx(cx.tcx).unwrap();
 
@@ -189,7 +199,7 @@ fn clean_poly_trait_ref_with_bindings<'tcx>(
     )
 }
 
-fn clean_lifetime<'tcx>(lifetime: hir::Lifetime, cx: &mut DocContext<'tcx>) -> Lifetime {
+fn clean_lifetime<'tcx>(lifetime: &hir::Lifetime, cx: &mut DocContext<'tcx>) -> Lifetime {
     let def = cx.tcx.named_region(lifetime.hir_id);
     if let Some(
         rl::Region::EarlyBound(node_id)
@@ -240,7 +250,6 @@ pub(crate) fn clean_middle_region<'tcx>(region: ty::Region<'tcx>) -> Option<Life
         | ty::ReFree(..)
         | ty::ReVar(..)
         | ty::RePlaceholder(..)
-        | ty::ReEmpty(_)
         | ty::ReErased => {
             debug!("cannot clean region {:?}", region);
             None
@@ -327,7 +336,7 @@ fn clean_poly_trait_predicate<'tcx>(
     let poly_trait_ref = pred.map_bound(|pred| pred.trait_ref);
     Some(WherePredicate::BoundPredicate {
         ty: clean_middle_ty(poly_trait_ref.skip_binder().self_ty(), cx, None),
-        bounds: vec![clean_poly_trait_ref_with_bindings(cx, poly_trait_ref, &[])],
+        bounds: vec![clean_poly_trait_ref_with_bindings(cx, poly_trait_ref, ThinVec::new())],
         bound_params: Vec::new(),
     })
 }
@@ -337,10 +346,6 @@ fn clean_region_outlives_predicate<'tcx>(
 ) -> Option<WherePredicate> {
     let ty::OutlivesPredicate(a, b) = pred;
 
-    if a.is_empty() && b.is_empty() {
-        return None;
-    }
-
     Some(WherePredicate::RegionPredicate {
         lifetime: clean_middle_region(a).expect("failed to clean lifetime"),
         bounds: vec![GenericBound::Outlives(
@@ -355,10 +360,6 @@ fn clean_type_outlives_predicate<'tcx>(
 ) -> Option<WherePredicate> {
     let ty::OutlivesPredicate(ty, lt) = pred;
 
-    if lt.is_empty() {
-        return None;
-    }
-
     Some(WherePredicate::BoundPredicate {
         ty: clean_middle_ty(ty, cx, None),
         bounds: vec![GenericBound::Outlives(
@@ -369,9 +370,9 @@ fn clean_type_outlives_predicate<'tcx>(
 }
 
 fn clean_middle_term<'tcx>(term: ty::Term<'tcx>, cx: &mut DocContext<'tcx>) -> Term {
-    match term {
-        ty::Term::Ty(ty) => Term::Type(clean_middle_ty(ty, cx, None)),
-        ty::Term::Const(c) => Term::Constant(clean_middle_const(c, cx)),
+    match term.unpack() {
+        ty::TermKind::Ty(ty) => Term::Type(clean_middle_ty(ty, cx, None)),
+        ty::TermKind::Const(c) => Term::Constant(clean_middle_const(c, cx)),
     }
 }
 
@@ -402,7 +403,7 @@ fn clean_projection<'tcx>(
     def_id: Option<DefId>,
 ) -> Type {
     let lifted = ty.lift_to_tcx(cx.tcx).unwrap();
-    let trait_ = clean_trait_ref_with_bindings(cx, lifted.trait_ref(cx.tcx), &[]);
+    let trait_ = clean_trait_ref_with_bindings(cx, lifted.trait_ref(cx.tcx), ThinVec::new());
     let self_type = clean_middle_ty(ty.self_ty(), cx, None);
     let self_def_id = if let Some(def_id) = def_id {
         cx.tcx.opt_parent(def_id).or(Some(def_id))
@@ -494,7 +495,7 @@ fn clean_generic_param<'tcx>(
                     .filter(|bp| !bp.in_where_clause)
                     .flat_map(|bp| bp.bounds)
                     .map(|bound| match bound {
-                        hir::GenericBound::Outlives(lt) => clean_lifetime(*lt, cx),
+                        hir::GenericBound::Outlives(lt) => clean_lifetime(lt, cx),
                         _ => panic!(),
                     })
                     .collect()
@@ -1079,7 +1080,7 @@ pub(crate) fn clean_impl_item<'tcx>(
         let mut what_rustc_thinks =
             Item::from_def_id_and_parts(local_did, Some(impl_.ident.name), inner, cx);
 
-        let impl_ref = cx.tcx.impl_trait_ref(cx.tcx.local_parent(impl_.def_id));
+        let impl_ref = cx.tcx.impl_trait_ref(cx.tcx.local_parent(impl_.def_id.def_id));
 
         // Trait impl items always inherit the impl's visibility --
         // we don't want to show `pub`.
@@ -1324,7 +1325,7 @@ fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type
                 segments: trait_segments.iter().map(|x| clean_path_segment(x, cx)).collect(),
             };
             register_res(cx, trait_.res);
-            let self_def_id = DefId::local(qself.hir_id.owner.local_def_index);
+            let self_def_id = DefId::local(qself.hir_id.owner.def_id.local_def_index);
             let self_type = clean_ty(qself, cx);
             let should_show_cast = compute_should_show_cast(Some(self_def_id), &trait_, &self_type);
             Type::QPath(Box::new(QPathData {
@@ -1391,7 +1392,7 @@ fn maybe_expand_private_type_alias<'tcx>(
                     }
                     _ => None,
                 });
-                if let Some(lt) = lifetime.cloned() {
+                if let Some(lt) = lifetime {
                     let lt_def_id = cx.tcx.hir().local_def_id(param.hir_id);
                     let cleaned =
                         if !lt.is_elided() { clean_lifetime(lt, cx) } else { Lifetime::elided() };
@@ -1491,7 +1492,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
             Array(Box::new(clean_ty(ty, cx)), length)
         }
         TyKind::Tup(tys) => Tuple(tys.iter().map(|ty| clean_ty(ty, cx)).collect()),
-        TyKind::OpaqueDef(item_id, _) => {
+        TyKind::OpaqueDef(item_id, _, _) => {
             let item = cx.tcx.hir().item(item_id);
             if let hir::ItemKind::OpaqueTy(ref ty) = item.kind {
                 ImplTrait(ty.bounds.iter().filter_map(|x| clean_generic_bound(x, cx)).collect())
@@ -1591,15 +1592,15 @@ pub(crate) fn clean_middle_ty<'tcx>(
                 AdtKind::Enum => ItemType::Enum,
             };
             inline::record_extern_fqn(cx, did, kind);
-            let path = external_path(cx, did, false, vec![], substs);
+            let path = external_path(cx, did, false, ThinVec::new(), substs);
             Type::Path { path }
         }
         ty::Foreign(did) => {
             inline::record_extern_fqn(cx, did, ItemType::ForeignType);
-            let path = external_path(cx, did, false, vec![], InternalSubsts::empty());
+            let path = external_path(cx, did, false, ThinVec::new(), InternalSubsts::empty());
             Type::Path { path }
         }
-        ty::Dynamic(obj, ref reg) => {
+        ty::Dynamic(obj, ref reg, _) => {
             // HACK: pick the first `did` as the `did` of the trait object. Someone
             // might want to implement "native" support for marker-trait-only
             // trait objects.
@@ -1620,7 +1621,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
             let mut bounds = dids
                 .map(|did| {
                     let empty = cx.tcx.intern_substs(&[]);
-                    let path = external_path(cx, did, false, vec![], empty);
+                    let path = external_path(cx, did, false, ThinVec::new(), empty);
                     inline::record_extern_fqn(cx, did, ItemType::Trait);
                     PolyTrait { trait_: path, generic_params: Vec::new() }
                 })
@@ -1696,7 +1697,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
                         }
                     }
 
-                    let bindings: Vec<_> = bounds
+                    let bindings: ThinVec<_> = bounds
                         .iter()
                         .filter_map(|bound| {
                             if let ty::PredicateKind::Projection(proj) = bound.kind().skip_binder()
@@ -1717,7 +1718,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
                         })
                         .collect();
 
-                    Some(clean_poly_trait_ref_with_bindings(cx, trait_ref, &bindings))
+                    Some(clean_poly_trait_ref_with_bindings(cx, trait_ref, bindings))
                 })
                 .collect::<Vec<_>>();
             bounds.extend(regions);
@@ -1776,7 +1777,7 @@ fn is_field_vis_inherited(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     }
 }
 
-pub(crate) fn clean_visibility(vis: ty::Visibility) -> Visibility {
+pub(crate) fn clean_visibility(vis: ty::Visibility<DefId>) -> Visibility {
     match vis {
         ty::Visibility::Public => Visibility::Public,
         ty::Visibility::Restricted(module) => Visibility::Restricted(module),
@@ -1785,7 +1786,10 @@ pub(crate) fn clean_visibility(vis: ty::Visibility) -> Visibility {
 
 pub(crate) fn clean_variant_def<'tcx>(variant: &ty::VariantDef, cx: &mut DocContext<'tcx>) -> Item {
     let kind = match variant.ctor_kind {
-        CtorKind::Const => Variant::CLike,
+        CtorKind::Const => Variant::CLike(match variant.discr {
+            ty::VariantDiscr::Explicit(def_id) => Some(Discriminant { expr: None, value: def_id }),
+            ty::VariantDiscr::Relative(_) => None,
+        }),
         CtorKind::Fn => Variant::Tuple(
             variant.fields.iter().map(|field| clean_middle_field(field, cx)).collect(),
         ),
@@ -1802,6 +1806,7 @@ pub(crate) fn clean_variant_def<'tcx>(variant: &ty::VariantDef, cx: &mut DocCont
 
 fn clean_variant_data<'tcx>(
     variant: &hir::VariantData<'tcx>,
+    disr_expr: &Option<hir::AnonConst>,
     cx: &mut DocContext<'tcx>,
 ) -> Variant {
     match variant {
@@ -1812,7 +1817,10 @@ fn clean_variant_data<'tcx>(
         hir::VariantData::Tuple(..) => {
             Variant::Tuple(variant.fields().iter().map(|x| clean_field(x, cx)).collect())
         }
-        hir::VariantData::Unit(..) => Variant::CLike,
+        hir::VariantData::Unit(..) => Variant::CLike(disr_expr.map(|disr| Discriminant {
+            expr: Some(disr.body),
+            value: cx.tcx.hir().local_def_id(disr.hir_id).to_def_id(),
+        })),
     }
 }
 
@@ -1848,12 +1856,8 @@ fn clean_generic_args<'tcx>(
             })
             .collect::<Vec<_>>()
             .into();
-        let bindings = generic_args
-            .bindings
-            .iter()
-            .map(|x| clean_type_binding(x, cx))
-            .collect::<Vec<_>>()
-            .into();
+        let bindings =
+            generic_args.bindings.iter().map(|x| clean_type_binding(x, cx)).collect::<ThinVec<_>>();
         GenericArgs::AngleBracketed { args, bindings }
     }
 }
@@ -1970,7 +1974,7 @@ fn clean_maybe_renamed_item<'tcx>(
 }
 
 fn clean_variant<'tcx>(variant: &hir::Variant<'tcx>, cx: &mut DocContext<'tcx>) -> Item {
-    let kind = VariantItem(clean_variant_data(&variant.data, cx));
+    let kind = VariantItem(clean_variant_data(&variant.data, &variant.disr_expr, cx));
     let what_rustc_thinks =
         Item::from_hir_id_and_parts(variant.id, Some(variant.ident.name), kind, cx);
     // don't show `pub` for variants, which are always public
@@ -2033,7 +2037,7 @@ fn clean_extern_crate<'tcx>(
     cx: &mut DocContext<'tcx>,
 ) -> Vec<Item> {
     // this is the ID of the `extern crate` statement
-    let cnum = cx.tcx.extern_mod_stmt_cnum(krate.def_id).unwrap_or(LOCAL_CRATE);
+    let cnum = cx.tcx.extern_mod_stmt_cnum(krate.def_id.def_id).unwrap_or(LOCAL_CRATE);
     // this is the ID of the crate itself
     let crate_def_id = cnum.as_def_id();
     let attrs = cx.tcx.hir().attrs(krate.hir_id());
@@ -2095,7 +2099,7 @@ fn clean_use_statement<'tcx>(
     let attrs = cx.tcx.hir().attrs(import.hir_id());
     let inline_attr = attrs.lists(sym::doc).get_word_attr(sym::inline);
     let pub_underscore = visibility.is_public() && name == kw::Underscore;
-    let current_mod = cx.tcx.parent_module_from_def_id(import.def_id);
+    let current_mod = cx.tcx.parent_module_from_def_id(import.def_id.def_id);
 
     // The parent of the module in which this import resides. This
     // is the same as `current_mod` if that's already the top
@@ -2107,8 +2111,8 @@ fn clean_use_statement<'tcx>(
     // `pub(super)` or higher. If the current module is the top level
     // module, there isn't really a parent module, which makes the results
     // meaningless. In this case, we make sure the answer is `false`.
-    let is_visible_from_parent_mod = visibility.is_accessible_from(parent_mod.to_def_id(), cx.tcx)
-        && !current_mod.is_top_level_module();
+    let is_visible_from_parent_mod =
+        visibility.is_accessible_from(parent_mod, cx.tcx) && !current_mod.is_top_level_module();
 
     if pub_underscore {
         if let Some(ref inline) = inline_attr {
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 909a47d07b16..f06d2cf108de 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -8,6 +8,7 @@ use std::sync::OnceLock as OnceCell;
 use std::{cmp, fmt, iter};
 
 use arrayvec::ArrayVec;
+use thin_vec::ThinVec;
 
 use rustc_ast::attr;
 use rustc_ast::util::comments::beautify_doc_string;
@@ -15,7 +16,6 @@ use rustc_ast::{self as ast, AttrStyle};
 use rustc_attr::{ConstStability, Deprecation, Stability, StabilityLevel};
 use rustc_const_eval::const_eval::is_unstable_const_fn;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_data_structures::thin_vec::ThinVec;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
@@ -510,7 +510,7 @@ impl Item {
             .get(&self.item_id)
             .map_or(&[][..], |v| v.as_slice())
             .iter()
-            .filter_map(|ItemLink { link: s, link_text, did, ref fragment }| {
+            .filter_map(|ItemLink { link: s, link_text, page_id: did, ref fragment }| {
                 debug!(?did);
                 if let Ok((mut href, ..)) = href(*did, cx) {
                     debug!(?href);
@@ -1134,7 +1134,10 @@ pub(crate) struct ItemLink {
     /// This may not be the same as `link` if there was a disambiguator
     /// in an intra-doc link (e.g. \[`fn@f`\])
     pub(crate) link_text: String,
-    pub(crate) did: DefId,
+    /// The `DefId` of the Item whose **HTML Page** contains the item being
+    /// linked to. This will be different to `item_id` on item's that don't
+    /// have their own page, such as struct fields and enum variants.
+    pub(crate) page_id: DefId,
     /// The url fragment to append to the link
     pub(crate) fragment: Option<UrlFragment>,
 }
@@ -1303,7 +1306,7 @@ impl GenericBound {
     pub(crate) fn maybe_sized(cx: &mut DocContext<'_>) -> GenericBound {
         let did = cx.tcx.require_lang_item(LangItem::Sized, None);
         let empty = cx.tcx.intern_substs(&[]);
-        let path = external_path(cx, did, false, vec![], empty);
+        let path = external_path(cx, did, false, ThinVec::new(), empty);
         inline::record_extern_fqn(cx, did, ItemType::Trait);
         GenericBound::TraitBound(
             PolyTrait { trait_: path, generic_params: Vec::new() },
@@ -2098,7 +2101,7 @@ impl Enum {
 
 #[derive(Clone, Debug)]
 pub(crate) enum Variant {
-    CLike,
+    CLike(Option<Discriminant>),
     Tuple(Vec<Item>),
     Struct(VariantStruct),
 }
@@ -2107,11 +2110,31 @@ impl Variant {
     pub(crate) fn has_stripped_entries(&self) -> Option<bool> {
         match *self {
             Self::Struct(ref struct_) => Some(struct_.has_stripped_entries()),
-            Self::CLike | Self::Tuple(_) => None,
+            Self::CLike(..) | Self::Tuple(_) => None,
         }
     }
 }
 
+#[derive(Clone, Debug)]
+pub(crate) struct Discriminant {
+    // In the case of cross crate re-exports, we don't have the nessesary information
+    // to reconstruct the expression of the discriminant, only the value.
+    pub(super) expr: Option<BodyId>,
+    pub(super) value: DefId,
+}
+
+impl Discriminant {
+    /// Will be `None` in the case of cross-crate reexports, and may be
+    /// simplified
+    pub(crate) fn expr(&self, tcx: TyCtxt<'_>) -> Option<String> {
+        self.expr.map(|body| print_const_expr(tcx, body))
+    }
+    /// Will always be a machine readable number, without underscores or suffixes.
+    pub(crate) fn value(&self, tcx: TyCtxt<'_>) -> String {
+        print_evaluated_const(tcx, self.value, false).unwrap()
+    }
+}
+
 /// Small wrapper around [`rustc_span::Span`] that adds helper methods
 /// and enforces calling [`rustc_span::Span::source_callsite()`].
 #[derive(Copy, Clone, Debug)]
@@ -2338,7 +2361,7 @@ impl ConstantKind {
         match *self {
             ConstantKind::TyConst { .. } | ConstantKind::Anonymous { .. } => None,
             ConstantKind::Extern { def_id } | ConstantKind::Local { def_id, .. } => {
-                print_evaluated_const(tcx, def_id)
+                print_evaluated_const(tcx, def_id, true)
             }
         }
     }
@@ -2512,7 +2535,7 @@ mod size_asserts {
     // These are in alphabetical order, which is easy to maintain.
     static_assert_size!(Crate, 72); // frequently moved by-value
     static_assert_size!(DocFragment, 32);
-    static_assert_size!(GenericArg, 64);
+    static_assert_size!(GenericArg, 56);
     static_assert_size!(GenericArgs, 32);
     static_assert_size!(GenericParamDef, 56);
     static_assert_size!(Item, 56);
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index 718cbbd2b837..edcd81061f83 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -12,7 +12,6 @@ use crate::visit_lib::LibEmbargoVisitor;
 
 use rustc_ast as ast;
 use rustc_ast::tokenstream::TokenTree;
-use rustc_data_structures::thin_vec::ThinVec;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
@@ -23,6 +22,7 @@ use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_span::symbol::{kw, sym, Symbol};
 use std::fmt::Write as _;
 use std::mem;
+use thin_vec::ThinVec;
 
 #[cfg(test)]
 mod tests;
@@ -102,7 +102,7 @@ fn external_generic_args<'tcx>(
     cx: &mut DocContext<'tcx>,
     did: DefId,
     has_self: bool,
-    bindings: Vec<TypeBinding>,
+    bindings: ThinVec<TypeBinding>,
     substs: SubstsRef<'tcx>,
 ) -> GenericArgs {
     let args = substs_to_args(cx, substs, has_self);
@@ -112,7 +112,7 @@ fn external_generic_args<'tcx>(
             // The trait's first substitution is the one after self, if there is one.
             match substs.iter().nth(if has_self { 1 } else { 0 }).unwrap().expect_ty().kind() {
                 ty::Tuple(tys) => tys.iter().map(|t| clean_middle_ty(t, cx, None)).collect::<Vec<_>>().into(),
-                _ => return GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() },
+                _ => return GenericArgs::AngleBracketed { args: args.into(), bindings },
             };
         let output = None;
         // FIXME(#20299) return type comes from a projection now
@@ -130,7 +130,7 @@ pub(super) fn external_path<'tcx>(
     cx: &mut DocContext<'tcx>,
     did: DefId,
     has_self: bool,
-    bindings: Vec<TypeBinding>,
+    bindings: ThinVec<TypeBinding>,
     substs: SubstsRef<'tcx>,
 ) -> Path {
     let def_kind = cx.tcx.def_kind(did);
@@ -234,15 +234,13 @@ pub(crate) fn name_from_pat(p: &hir::Pat<'_>) -> Symbol {
 
 pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
     match n.kind() {
-        ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) => {
-            let mut s = if let Some(def) = def.as_local() {
+        ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs: _ }) => {
+            let s = if let Some(def) = def.as_local() {
                 print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(def.did))
             } else {
                 inline::print_inlined_const(cx.tcx, def.did)
             };
-            if let Some(promoted) = promoted {
-                s.push_str(&format!("::{:?}", promoted))
-            }
+
             s
         }
         _ => {
@@ -261,7 +259,11 @@ pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
     }
 }
 
-pub(crate) fn print_evaluated_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<String> {
+pub(crate) fn print_evaluated_const(
+    tcx: TyCtxt<'_>,
+    def_id: DefId,
+    underscores_and_type: bool,
+) -> Option<String> {
     tcx.const_eval_poly(def_id).ok().and_then(|val| {
         let ty = tcx.type_of(def_id);
         match (val, ty.kind()) {
@@ -269,7 +271,7 @@ pub(crate) fn print_evaluated_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<St
             (ConstValue::Scalar(_), &ty::Adt(_, _)) => None,
             (ConstValue::Scalar(_), _) => {
                 let const_ = mir::ConstantKind::from_value(val, ty);
-                Some(print_const_with_custom_print_scalar(tcx, const_))
+                Some(print_const_with_custom_print_scalar(tcx, const_, underscores_and_type))
             }
             _ => None,
         }
@@ -302,23 +304,35 @@ fn format_integer_with_underscore_sep(num: &str) -> String {
         .collect()
 }
 
-fn print_const_with_custom_print_scalar(tcx: TyCtxt<'_>, ct: mir::ConstantKind<'_>) -> String {
+fn print_const_with_custom_print_scalar(
+    tcx: TyCtxt<'_>,
+    ct: mir::ConstantKind<'_>,
+    underscores_and_type: bool,
+) -> String {
     // Use a slightly different format for integer types which always shows the actual value.
     // For all other types, fallback to the original `pretty_print_const`.
     match (ct, ct.ty().kind()) {
         (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Uint(ui)) => {
-            format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
+            if underscores_and_type {
+                format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
+            } else {
+                int.to_string()
+            }
         }
         (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Int(i)) => {
             let ty = tcx.lift(ct.ty()).unwrap();
             let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size;
             let data = int.assert_bits(size);
             let sign_extended_data = size.sign_extend(data) as i128;
-            format!(
-                "{}{}",
-                format_integer_with_underscore_sep(&sign_extended_data.to_string()),
-                i.name_str()
-            )
+            if underscores_and_type {
+                format!(
+                    "{}{}",
+                    format_integer_with_underscore_sep(&sign_extended_data.to_string()),
+                    i.name_str()
+                )
+            } else {
+                sign_extended_data.to_string()
+            }
         }
         _ => ct.to_string(),
     }
@@ -475,30 +489,14 @@ pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
     use DefKind::*;
     debug!("register_res({:?})", res);
 
-    let (did, kind) = match res {
-        // These should be added to the cache using `record_extern_fqn`.
+    let (kind, did) = match res {
         Res::Def(
             kind @ (AssocTy | AssocFn | AssocConst | Variant | Fn | TyAlias | Enum | Trait | Struct
             | Union | Mod | ForeignTy | Const | Static(_) | Macro(..) | TraitAlias),
-            i,
-        ) => (i, kind.into()),
-        // This is part of a trait definition or trait impl; document the trait.
-        Res::SelfTy { trait_: Some(trait_def_id), alias_to: _ } => (trait_def_id, ItemType::Trait),
-        // This is an inherent impl or a type definition; it doesn't have its own page.
-        Res::SelfTy { trait_: None, alias_to: Some((item_def_id, _)) } => return item_def_id,
-        Res::SelfTy { trait_: None, alias_to: None }
-        | Res::PrimTy(_)
-        | Res::ToolMod
-        | Res::SelfCtor(_)
-        | Res::Local(_)
-        | Res::NonMacroAttr(_)
-        | Res::Err => return res.def_id(),
-        Res::Def(
-            TyParam | ConstParam | Ctor(..) | ExternCrate | Use | ForeignMod | AnonConst
-            | InlineConst | OpaqueTy | Field | LifetimeParam | GlobalAsm | Impl | Closure
-            | Generator,
-            id,
-        ) => return id,
+            did,
+        ) => (kind.into(), did),
+
+        _ => panic!("register_res: unexpected {:?}", res),
     };
     if did.is_local() {
         return did;
diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index 8a8cc272e819..932533db05c1 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -412,7 +412,13 @@ impl Options {
 
         let to_check = matches.opt_strs("check-theme");
         if !to_check.is_empty() {
-            let paths = theme::load_css_paths(static_files::themes::LIGHT.as_bytes());
+            let paths = match theme::load_css_paths(static_files::themes::LIGHT) {
+                Ok(p) => p,
+                Err(e) => {
+                    diag.struct_err(&e.to_string()).emit();
+                    return Err(1);
+                }
+            };
             let mut errors = 0;
 
             println!("rustdoc: [check-theme] Starting tests! (Ignoring all other arguments)");
@@ -547,7 +553,13 @@ impl Options {
 
         let mut themes = Vec::new();
         if matches.opt_present("theme") {
-            let paths = theme::load_css_paths(static_files::themes::LIGHT.as_bytes());
+            let paths = match theme::load_css_paths(static_files::themes::LIGHT) {
+                Ok(p) => p,
+                Err(e) => {
+                    diag.struct_err(&e.to_string()).emit();
+                    return Err(1);
+                }
+            };
 
             for (theme_file, theme_s) in
                 matches.opt_strs("theme").iter().map(|s| (PathBuf::from(&s), s.to_owned()))
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index c48b25aea4a3..76562d26a550 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -10,7 +10,6 @@ use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{HirId, Path, TraitCandidate};
 use rustc_interface::interface;
 use rustc_middle::hir::nested_filter;
-use rustc_middle::middle::privacy::AccessLevels;
 use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
 use rustc_resolve as resolve;
 use rustc_session::config::{self, CrateType, ErrorOutputType};
@@ -364,9 +363,7 @@ pub(crate) fn run_global_ctxt(
         .copied()
         .filter(|&trait_def_id| tcx.trait_is_auto(trait_def_id))
         .collect();
-    let access_levels = AccessLevels {
-        map: tcx.privacy_access_levels(()).map.iter().map(|(k, v)| (k.to_def_id(), *v)).collect(),
-    };
+    let access_levels = tcx.privacy_access_levels(()).map_id(Into::into);
 
     let mut ctxt = DocContext {
         tcx,
diff --git a/src/librustdoc/fold.rs b/src/librustdoc/fold.rs
index 6b7e67e2ce34..ed702f5c4a9c 100644
--- a/src/librustdoc/fold.rs
+++ b/src/librustdoc/fold.rs
@@ -46,7 +46,7 @@ pub(crate) trait DocFolder: Sized {
                     let fields = fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
                     VariantItem(Variant::Tuple(fields))
                 }
-                Variant::CLike => VariantItem(Variant::CLike),
+                Variant::CLike(disr) => VariantItem(Variant::CLike(disr)),
             },
             ExternCrateItem { src: _ }
             | ImportItem(_)
diff --git a/src/librustdoc/formats/item_type.rs b/src/librustdoc/formats/item_type.rs
index 0a7ee2005915..f21e60a64e00 100644
--- a/src/librustdoc/formats/item_type.rs
+++ b/src/librustdoc/formats/item_type.rs
@@ -135,6 +135,7 @@ impl From<DefKind> for ItemType {
             | DefKind::AnonConst
             | DefKind::InlineConst
             | DefKind::OpaqueTy
+            | DefKind::ImplTraitPlaceholder
             | DefKind::Field
             | DefKind::LifetimeParam
             | DefKind::GlobalAsm
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 6f49f00f93e5..b499e186cc04 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -349,8 +349,7 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
         let where_preds = comma_sep(where_predicates, false);
         let clause = if f.alternate() {
             if ending == Ending::Newline {
-                // add a space so stripping <br> tags and breaking spaces still renders properly
-                format!(" where{where_preds}, ")
+                format!(" where{where_preds},")
             } else {
                 format!(" where{where_preds}")
             }
@@ -364,20 +363,16 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
 
             if ending == Ending::Newline {
                 let mut clause = "&nbsp;".repeat(indent.saturating_sub(1));
-                // add a space so stripping <br> tags and breaking spaces still renders properly
-                write!(
-                    clause,
-                    " <span class=\"where fmt-newline\">where{where_preds},&nbsp;</span>"
-                )?;
+                write!(clause, "<span class=\"where fmt-newline\">where{where_preds},</span>")?;
                 clause
             } else {
                 // insert a <br> tag after a single space but before multiple spaces at the start
                 if indent == 0 {
-                    format!(" <br><span class=\"where\">where{where_preds}</span>")
+                    format!("<br><span class=\"where\">where{where_preds}</span>")
                 } else {
                     let mut clause = br_with_padding;
-                    clause.truncate(clause.len() - 5 * "&nbsp;".len());
-                    write!(clause, " <span class=\"where\">where{where_preds}</span>")?;
+                    clause.truncate(clause.len() - 4 * "&nbsp;".len());
+                    write!(clause, "<span class=\"where\">where{where_preds}</span>")?;
                     clause
                 }
             }
@@ -592,7 +587,7 @@ fn generate_macro_def_id_path(
             }
         })
         .collect();
-    let relative = fqp.iter().map(|elem| elem.to_string());
+    let mut relative = fqp.iter().map(|elem| elem.to_string());
     let cstore = CStore::from_tcx(tcx);
     // We need this to prevent a `panic` when this function is used from intra doc links...
     if !cstore.has_crate_data(def_id.krate) {
@@ -612,7 +607,7 @@ fn generate_macro_def_id_path(
     let mut path = if is_macro_2 {
         once(crate_name.clone()).chain(relative).collect()
     } else {
-        vec![crate_name.clone(), relative.last().unwrap()]
+        vec![crate_name.clone(), relative.next_back().unwrap()]
     };
     if path.len() < 2 {
         // The minimum we can have is the crate name followed by the macro name. If shorter, then
diff --git a/src/librustdoc/html/highlight.rs b/src/librustdoc/html/highlight.rs
index 4a12d74ddef5..8922bf377858 100644
--- a/src/librustdoc/html/highlight.rs
+++ b/src/librustdoc/html/highlight.rs
@@ -29,6 +29,8 @@ pub(crate) struct HrefContext<'a, 'b, 'c> {
     /// This field is used to know "how far" from the top of the directory we are to link to either
     /// documentation pages or other source pages.
     pub(crate) root_path: &'c str,
+    /// This field is used to calculate precise local URLs.
+    pub(crate) current_href: &'c str,
 }
 
 /// Decorations are represented as a map from CSS class to vector of character ranges.
@@ -52,35 +54,14 @@ pub(crate) fn render_example_with_highlighting(
     tooltip: Tooltip,
     playground_button: Option<&str>,
 ) {
-    let class = match tooltip {
-        Tooltip::Ignore => " ignore",
-        Tooltip::CompileFail => " compile_fail",
-        Tooltip::ShouldPanic => " should_panic",
-        Tooltip::Edition(_) => " edition",
-        Tooltip::None => "",
-    };
-
-    if tooltip != Tooltip::None {
-        write!(
-            out,
-            "<div class='information'><div class='tooltip{}'{}>ⓘ</div></div>",
-            class,
-            if let Tooltip::Edition(edition_info) = tooltip {
-                format!(" data-edition=\"{}\"", edition_info)
-            } else {
-                String::new()
-            },
-        );
-    }
-
-    write_header(out, &format!("rust-example-rendered{}", class), None);
+    write_header(out, "rust-example-rendered", None, tooltip);
     write_code(out, src, None, None);
     write_footer(out, playground_button);
 }
 
 /// Highlights `src` as a macro, returning the HTML output.
 pub(crate) fn render_macro_with_highlighting(src: &str, out: &mut Buffer) {
-    write_header(out, "macro", None);
+    write_header(out, "macro", None, Tooltip::None);
     write_code(out, src, None, None);
     write_footer(out, None);
 }
@@ -93,20 +74,43 @@ pub(crate) fn render_source_with_highlighting(
     href_context: HrefContext<'_, '_, '_>,
     decoration_info: DecorationInfo,
 ) {
-    write_header(out, "", Some(line_numbers));
+    write_header(out, "", Some(line_numbers), Tooltip::None);
     write_code(out, src, Some(href_context), Some(decoration_info));
     write_footer(out, None);
 }
 
-fn write_header(out: &mut Buffer, class: &str, extra_content: Option<Buffer>) {
-    write!(out, "<div class=\"example-wrap\">");
+fn write_header(out: &mut Buffer, class: &str, extra_content: Option<Buffer>, tooltip: Tooltip) {
+    write!(
+        out,
+        "<div class=\"example-wrap{}\">",
+        match tooltip {
+            Tooltip::Ignore => " ignore",
+            Tooltip::CompileFail => " compile_fail",
+            Tooltip::ShouldPanic => " should_panic",
+            Tooltip::Edition(_) => " edition",
+            Tooltip::None => "",
+        },
+    );
+
+    if tooltip != Tooltip::None {
+        write!(
+            out,
+            "<div class='tooltip'{}>ⓘ</div>",
+            if let Tooltip::Edition(edition_info) = tooltip {
+                format!(" data-edition=\"{}\"", edition_info)
+            } else {
+                String::new()
+            },
+        );
+    }
+
     if let Some(extra) = extra_content {
         out.push_buffer(extra);
     }
     if class.is_empty() {
         write!(out, "<pre class=\"rust\">");
     } else {
-        write!(out, "<pre class=\"rust {}\">", class);
+        write!(out, "<pre class=\"rust {class}\">");
     }
     write!(out, "<code>");
 }
@@ -450,7 +454,7 @@ impl<'a> PeekIter<'a> {
     fn new(iter: TokenIter<'a>) -> Self {
         Self { stored: VecDeque::new(), peek_pos: 0, iter }
     }
-    /// Returns the next item after the current one. It doesn't interfer with `peek_next` output.
+    /// Returns the next item after the current one. It doesn't interfere with `peek_next` output.
     fn peek(&mut self) -> Option<&(TokenKind, &'a str)> {
         if self.stored.is_empty() {
             if let Some(next) = self.iter.next() {
@@ -459,7 +463,7 @@ impl<'a> PeekIter<'a> {
         }
         self.stored.front()
     }
-    /// Returns the next item after the last one peeked. It doesn't interfer with `peek` output.
+    /// Returns the next item after the last one peeked. It doesn't interfere with `peek` output.
     fn peek_next(&mut self) -> Option<&(TokenKind, &'a str)> {
         self.peek_pos += 1;
         if self.peek_pos - 1 < self.stored.len() {
@@ -975,9 +979,9 @@ fn string_without_closing_tag<T: Display>(
                 // a link to their definition can be generated using this:
                 // https://github.com/rust-lang/rust/blob/60f1a2fc4b535ead9c85ce085fdce49b1b097531/src/librustdoc/html/render/context.rs#L315-L338
                 match href {
-                    LinkFromSrc::Local(span) => context
-                        .href_from_span(*span, true)
-                        .map(|s| format!("{}{}", href_context.root_path, s)),
+                    LinkFromSrc::Local(span) => {
+                        context.href_from_span_relative(*span, href_context.current_href)
+                    }
                     LinkFromSrc::External(def_id) => {
                         format::href_with_root_path(*def_id, context, Some(href_context.root_path))
                             .ok()
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index ec2e129c364e..8e53fbbcd197 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -111,14 +111,9 @@ pub(crate) struct MarkdownWithToc<'a>(
     pub(crate) Edition,
     pub(crate) &'a Option<Playground>,
 );
-/// A tuple struct like `Markdown` that renders the markdown escaping HTML tags.
-pub(crate) struct MarkdownHtml<'a>(
-    pub(crate) &'a str,
-    pub(crate) &'a mut IdMap,
-    pub(crate) ErrorCodes,
-    pub(crate) Edition,
-    pub(crate) &'a Option<Playground>,
-);
+/// A tuple struct like `Markdown` that renders the markdown escaping HTML tags
+/// and includes no paragraph tags.
+pub(crate) struct MarkdownItemInfo<'a>(pub(crate) &'a str, pub(crate) &'a mut IdMap);
 /// A tuple struct like `Markdown` that renders only the first paragraph.
 pub(crate) struct MarkdownSummaryLine<'a>(pub &'a str, pub &'a [RenderedLink]);
 
@@ -1072,9 +1067,9 @@ impl MarkdownWithToc<'_> {
     }
 }
 
-impl MarkdownHtml<'_> {
+impl MarkdownItemInfo<'_> {
     pub(crate) fn into_string(self) -> String {
-        let MarkdownHtml(md, ids, codes, edition, playground) = self;
+        let MarkdownItemInfo(md, ids) = self;
 
         // This is actually common enough to special-case
         if md.is_empty() {
@@ -1093,7 +1088,9 @@ impl MarkdownHtml<'_> {
         let p = HeadingLinks::new(p, None, ids, HeadingOffset::H1);
         let p = Footnotes::new(p);
         let p = TableWrapper::new(p.map(|(ev, _)| ev));
-        let p = CodeBlocks::new(p, codes, edition, playground);
+        let p = p.filter(|event| {
+            !matches!(event, Event::Start(Tag::Paragraph) | Event::End(Tag::Paragraph))
+        });
         html::push_html(&mut s, p);
 
         s
@@ -1119,7 +1116,11 @@ impl MarkdownSummaryLine<'_> {
 
         let mut s = String::new();
 
-        html::push_html(&mut s, LinkReplacer::new(SummaryLine::new(p), links));
+        let without_paragraphs = LinkReplacer::new(SummaryLine::new(p), links).filter(|event| {
+            !matches!(event, Event::Start(Tag::Paragraph) | Event::End(Tag::Paragraph))
+        });
+
+        html::push_html(&mut s, without_paragraphs);
 
         s
     }
diff --git a/src/librustdoc/html/markdown/tests.rs b/src/librustdoc/html/markdown/tests.rs
index 5c0bf0ed942f..e4f72a057892 100644
--- a/src/librustdoc/html/markdown/tests.rs
+++ b/src/librustdoc/html/markdown/tests.rs
@@ -1,5 +1,5 @@
 use super::{find_testable_code, plain_text_summary, short_markdown_summary};
-use super::{ErrorCodes, HeadingOffset, IdMap, Ignore, LangString, Markdown, MarkdownHtml};
+use super::{ErrorCodes, HeadingOffset, IdMap, Ignore, LangString, Markdown, MarkdownItemInfo};
 use rustc_span::edition::{Edition, DEFAULT_EDITION};
 
 #[test]
@@ -279,14 +279,13 @@ fn test_plain_text_summary() {
 fn test_markdown_html_escape() {
     fn t(input: &str, expect: &str) {
         let mut idmap = IdMap::new();
-        let output =
-            MarkdownHtml(input, &mut idmap, ErrorCodes::Yes, DEFAULT_EDITION, &None).into_string();
+        let output = MarkdownItemInfo(input, &mut idmap).into_string();
         assert_eq!(output, expect, "original: {}", input);
     }
 
-    t("`Struct<'a, T>`", "<p><code>Struct&lt;'a, T&gt;</code></p>\n");
-    t("Struct<'a, T>", "<p>Struct&lt;’a, T&gt;</p>\n");
-    t("Struct<br>", "<p>Struct&lt;br&gt;</p>\n");
+    t("`Struct<'a, T>`", "<code>Struct&lt;'a, T&gt;</code>");
+    t("Struct<'a, T>", "Struct&lt;’a, T&gt;");
+    t("Struct<br>", "Struct&lt;br&gt;");
 }
 
 #[test]
diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
index 01b96dc72155..22a6fcd316aa 100644
--- a/src/librustdoc/html/render/context.rs
+++ b/src/librustdoc/html/render/context.rs
@@ -17,8 +17,8 @@ use super::print_item::{full_path, item_path, print_item};
 use super::search_index::build_index;
 use super::write_shared::write_shared;
 use super::{
-    collect_spans_and_sources, print_sidebar, scrape_examples_help, AllTypes, LinkFromSrc, NameDoc,
-    StylePath, BASIC_KEYWORDS,
+    collect_spans_and_sources, print_sidebar, scrape_examples_help, sidebar_module_like, AllTypes,
+    LinkFromSrc, NameDoc, StylePath, BASIC_KEYWORDS,
 };
 
 use crate::clean::{self, types::ExternalLocation, ExternalCrate};
@@ -31,6 +31,7 @@ use crate::formats::FormatRenderer;
 use crate::html::escape::Escape;
 use crate::html::format::{join_with_double_colon, Buffer};
 use crate::html::markdown::{self, plain_text_summary, ErrorCodes, IdMap};
+use crate::html::url_parts_builder::UrlPartsBuilder;
 use crate::html::{layout, sources};
 use crate::scrape_examples::AllCallLocations;
 use crate::try_err;
@@ -370,6 +371,35 @@ impl<'tcx> Context<'tcx> {
             anchor = anchor
         ))
     }
+
+    pub(crate) fn href_from_span_relative(
+        &self,
+        span: clean::Span,
+        relative_to: &str,
+    ) -> Option<String> {
+        self.href_from_span(span, false).map(|s| {
+            let mut url = UrlPartsBuilder::new();
+            let mut dest_href_parts = s.split('/');
+            let mut cur_href_parts = relative_to.split('/');
+            for (cur_href_part, dest_href_part) in (&mut cur_href_parts).zip(&mut dest_href_parts) {
+                if cur_href_part != dest_href_part {
+                    url.push(dest_href_part);
+                    break;
+                }
+            }
+            for dest_href_part in dest_href_parts {
+                url.push(dest_href_part);
+            }
+            let loline = span.lo(self.sess()).line;
+            let hiline = span.hi(self.sess()).line;
+            format!(
+                "{}{}#{}",
+                "../".repeat(cur_href_parts.count()),
+                url.finish(),
+                if loline == hiline { loline.to_string() } else { format!("{loline}-{hiline}") }
+            )
+        })
+    }
 }
 
 /// Generates the documentation for `crate` into the directory `dst`
@@ -567,16 +597,24 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             keywords: BASIC_KEYWORDS,
             resource_suffix: &shared.resource_suffix,
         };
-        let sidebar = if shared.cache.crate_version.is_some() {
-            format!("<h2 class=\"location\">Crate {}</h2>", crate_name)
-        } else {
-            String::new()
-        };
         let all = shared.all.replace(AllTypes::new());
+        let mut sidebar = Buffer::html();
+        if shared.cache.crate_version.is_some() {
+            write!(sidebar, "<h2 class=\"location\">Crate {}</h2>", crate_name)
+        };
+
+        let mut items = Buffer::html();
+        sidebar_module_like(&mut items, all.item_sections());
+        if !items.is_empty() {
+            sidebar.push_str("<div class=\"sidebar-elems\">");
+            sidebar.push_buffer(items);
+            sidebar.push_str("</div>");
+        }
+
         let v = layout::render(
             &shared.layout,
             &page,
-            sidebar,
+            sidebar.into_inner(),
             |buf: &mut Buffer| all.print(buf),
             &shared.style_files,
         );
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index eff34047e3c8..75ac11a3a886 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -74,7 +74,9 @@ use crate::html::format::{
     PrintWithSpace,
 };
 use crate::html::highlight;
-use crate::html::markdown::{HeadingOffset, IdMap, Markdown, MarkdownHtml, MarkdownSummaryLine};
+use crate::html::markdown::{
+    HeadingOffset, IdMap, Markdown, MarkdownItemInfo, MarkdownSummaryLine,
+};
 use crate::html::sources;
 use crate::html::static_files::SCRAPE_EXAMPLES_HELP_MD;
 use crate::scrape_examples::{CallData, CallLocation};
@@ -239,8 +241,8 @@ struct AllTypes {
     opaque_tys: FxHashSet<ItemEntry>,
     statics: FxHashSet<ItemEntry>,
     constants: FxHashSet<ItemEntry>,
-    attributes: FxHashSet<ItemEntry>,
-    derives: FxHashSet<ItemEntry>,
+    attribute_macros: FxHashSet<ItemEntry>,
+    derive_macros: FxHashSet<ItemEntry>,
     trait_aliases: FxHashSet<ItemEntry>,
 }
 
@@ -259,8 +261,8 @@ impl AllTypes {
             opaque_tys: new_set(100),
             statics: new_set(100),
             constants: new_set(100),
-            attributes: new_set(100),
-            derives: new_set(100),
+            attribute_macros: new_set(100),
+            derive_macros: new_set(100),
             trait_aliases: new_set(100),
         }
     }
@@ -283,27 +285,75 @@ impl AllTypes {
                 ItemType::OpaqueTy => self.opaque_tys.insert(ItemEntry::new(new_url, name)),
                 ItemType::Static => self.statics.insert(ItemEntry::new(new_url, name)),
                 ItemType::Constant => self.constants.insert(ItemEntry::new(new_url, name)),
-                ItemType::ProcAttribute => self.attributes.insert(ItemEntry::new(new_url, name)),
-                ItemType::ProcDerive => self.derives.insert(ItemEntry::new(new_url, name)),
+                ItemType::ProcAttribute => {
+                    self.attribute_macros.insert(ItemEntry::new(new_url, name))
+                }
+                ItemType::ProcDerive => self.derive_macros.insert(ItemEntry::new(new_url, name)),
                 ItemType::TraitAlias => self.trait_aliases.insert(ItemEntry::new(new_url, name)),
                 _ => true,
             };
         }
     }
-}
 
-impl AllTypes {
+    fn item_sections(&self) -> FxHashSet<ItemSection> {
+        let mut sections = FxHashSet::default();
+
+        if !self.structs.is_empty() {
+            sections.insert(ItemSection::Structs);
+        }
+        if !self.enums.is_empty() {
+            sections.insert(ItemSection::Enums);
+        }
+        if !self.unions.is_empty() {
+            sections.insert(ItemSection::Unions);
+        }
+        if !self.primitives.is_empty() {
+            sections.insert(ItemSection::PrimitiveTypes);
+        }
+        if !self.traits.is_empty() {
+            sections.insert(ItemSection::Traits);
+        }
+        if !self.macros.is_empty() {
+            sections.insert(ItemSection::Macros);
+        }
+        if !self.functions.is_empty() {
+            sections.insert(ItemSection::Functions);
+        }
+        if !self.typedefs.is_empty() {
+            sections.insert(ItemSection::TypeDefinitions);
+        }
+        if !self.opaque_tys.is_empty() {
+            sections.insert(ItemSection::OpaqueTypes);
+        }
+        if !self.statics.is_empty() {
+            sections.insert(ItemSection::Statics);
+        }
+        if !self.constants.is_empty() {
+            sections.insert(ItemSection::Constants);
+        }
+        if !self.attribute_macros.is_empty() {
+            sections.insert(ItemSection::AttributeMacros);
+        }
+        if !self.derive_macros.is_empty() {
+            sections.insert(ItemSection::DeriveMacros);
+        }
+        if !self.trait_aliases.is_empty() {
+            sections.insert(ItemSection::TraitAliases);
+        }
+
+        sections
+    }
+
     fn print(self, f: &mut Buffer) {
-        fn print_entries(f: &mut Buffer, e: &FxHashSet<ItemEntry>, title: &str, class: &str) {
+        fn print_entries(f: &mut Buffer, e: &FxHashSet<ItemEntry>, kind: ItemSection) {
             if !e.is_empty() {
                 let mut e: Vec<&ItemEntry> = e.iter().collect();
                 e.sort();
                 write!(
                     f,
-                    "<h3 id=\"{}\">{}</h3><ul class=\"{} docblock\">",
-                    title.replace(' ', "-"), // IDs cannot contain whitespaces.
-                    title,
-                    class
+                    "<h3 id=\"{id}\">{title}</h3><ul class=\"all-items\">",
+                    id = kind.id(),
+                    title = kind.name(),
                 );
 
                 for s in e.iter() {
@@ -321,20 +371,20 @@ impl AllTypes {
         );
         // Note: print_entries does not escape the title, because we know the current set of titles
         // doesn't require escaping.
-        print_entries(f, &self.structs, "Structs", "structs");
-        print_entries(f, &self.enums, "Enums", "enums");
-        print_entries(f, &self.unions, "Unions", "unions");
-        print_entries(f, &self.primitives, "Primitives", "primitives");
-        print_entries(f, &self.traits, "Traits", "traits");
-        print_entries(f, &self.macros, "Macros", "macros");
-        print_entries(f, &self.attributes, "Attribute Macros", "attributes");
-        print_entries(f, &self.derives, "Derive Macros", "derives");
-        print_entries(f, &self.functions, "Functions", "functions");
-        print_entries(f, &self.typedefs, "Typedefs", "typedefs");
-        print_entries(f, &self.trait_aliases, "Trait Aliases", "trait-aliases");
-        print_entries(f, &self.opaque_tys, "Opaque Types", "opaque-types");
-        print_entries(f, &self.statics, "Statics", "statics");
-        print_entries(f, &self.constants, "Constants", "constants")
+        print_entries(f, &self.structs, ItemSection::Structs);
+        print_entries(f, &self.enums, ItemSection::Enums);
+        print_entries(f, &self.unions, ItemSection::Unions);
+        print_entries(f, &self.primitives, ItemSection::PrimitiveTypes);
+        print_entries(f, &self.traits, ItemSection::Traits);
+        print_entries(f, &self.macros, ItemSection::Macros);
+        print_entries(f, &self.attribute_macros, ItemSection::AttributeMacros);
+        print_entries(f, &self.derive_macros, ItemSection::DeriveMacros);
+        print_entries(f, &self.functions, ItemSection::Functions);
+        print_entries(f, &self.typedefs, ItemSection::TypeDefinitions);
+        print_entries(f, &self.trait_aliases, ItemSection::TraitAliases);
+        print_entries(f, &self.opaque_tys, ItemSection::OpaqueTypes);
+        print_entries(f, &self.statics, ItemSection::Statics);
+        print_entries(f, &self.constants, ItemSection::Constants);
     }
 }
 
@@ -536,7 +586,6 @@ fn short_item_info(
     parent: Option<&clean::Item>,
 ) -> Vec<String> {
     let mut extra_info = vec![];
-    let error_codes = cx.shared.codes;
 
     if let Some(depr @ Deprecation { note, since, is_since_rustc_version: _, suggestion: _ }) =
         item.deprecation(cx.tcx())
@@ -560,13 +609,7 @@ fn short_item_info(
 
         if let Some(note) = note {
             let note = note.as_str();
-            let html = MarkdownHtml(
-                note,
-                &mut cx.id_map,
-                error_codes,
-                cx.shared.edition(),
-                &cx.shared.playground,
-            );
+            let html = MarkdownItemInfo(note, &mut cx.id_map);
             message.push_str(&format!(": {}", html.into_string()));
         }
         extra_info.push(format!(
@@ -1737,8 +1780,8 @@ pub(crate) fn render_impl_summary(
     // in documentation pages for trait with automatic implementations like "Send" and "Sync".
     aliases: &[String],
 ) {
-    let id =
-        cx.derive_id(get_id_for_impl(&i.inner_impl().for_, i.inner_impl().trait_.as_ref(), cx));
+    let inner_impl = i.inner_impl();
+    let id = cx.derive_id(get_id_for_impl(&inner_impl.for_, inner_impl.trait_.as_ref(), cx));
     let aliases = if aliases.is_empty() {
         String::new()
     } else {
@@ -1747,12 +1790,12 @@ pub(crate) fn render_impl_summary(
     write!(w, "<section id=\"{}\" class=\"impl has-srclink\"{}>", id, aliases);
     render_rightside(w, cx, &i.impl_item, containing_item, RenderMode::Normal);
     write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
-    write!(w, "<h3 class=\"code-header in-band\">");
+    write!(w, "<h3 class=\"code-header\">");
 
     if let Some(use_absolute) = use_absolute {
-        write!(w, "{}", i.inner_impl().print(use_absolute, cx));
+        write!(w, "{}", inner_impl.print(use_absolute, cx));
         if show_def_docs {
-            for it in &i.inner_impl().items {
+            for it in &inner_impl.items {
                 if let clean::AssocTypeItem(ref tydef, ref _bounds) = *it.kind {
                     w.write_str("<span class=\"where fmt-newline\">  ");
                     assoc_type(
@@ -1770,11 +1813,11 @@ pub(crate) fn render_impl_summary(
             }
         }
     } else {
-        write!(w, "{}", i.inner_impl().print(false, cx));
+        write!(w, "{}", inner_impl.print(false, cx));
     }
     write!(w, "</h3>");
 
-    let is_trait = i.inner_impl().trait_.is_some();
+    let is_trait = inner_impl.trait_.is_some();
     if is_trait {
         if let Some(portability) = portability(&i.impl_item, Some(parent)) {
             write!(w, "<span class=\"item-info\">{}</span>", portability);
@@ -2367,9 +2410,9 @@ pub(crate) fn get_filtered_impls_for_reference<'a>(
     let Some(v) = shared.cache.impls.get(&def_id) else { return (Vec::new(), Vec::new(), Vec::new()) };
     // Since there is no "direct implementation" on the reference primitive type, we filter out
     // every implementation which isn't a trait implementation.
-    let traits: Vec<_> = v.iter().filter(|i| i.inner_impl().trait_.is_some()).collect();
+    let traits = v.iter().filter(|i| i.inner_impl().trait_.is_some());
     let (synthetic, concrete): (Vec<&Impl>, Vec<&Impl>) =
-        traits.into_iter().partition(|t| t.inner_impl().kind.is_auto());
+        traits.partition(|t| t.inner_impl().kind.is_auto());
 
     let (blanket_impl, concrete): (Vec<&Impl>, _) =
         concrete.into_iter().partition(|t| t.inner_impl().kind.is_blanket());
@@ -2469,7 +2512,7 @@ fn sidebar_enum(cx: &Context<'_>, buf: &mut Buffer, it: &clean::Item, e: &clean:
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
-enum ItemSection {
+pub(crate) enum ItemSection {
     Reexports,
     PrimitiveTypes,
     Modules,
@@ -2621,25 +2664,11 @@ fn item_ty_to_section(ty: ItemType) -> ItemSection {
     }
 }
 
-fn sidebar_module(buf: &mut Buffer, items: &[clean::Item]) {
+pub(crate) fn sidebar_module_like(buf: &mut Buffer, item_sections_in_use: FxHashSet<ItemSection>) {
     use std::fmt::Write as _;
 
     let mut sidebar = String::new();
 
-    let item_sections_in_use: FxHashSet<_> = items
-        .iter()
-        .filter(|it| {
-            !it.is_stripped()
-                && it
-                    .name
-                    .or_else(|| {
-                        if let clean::ImportItem(ref i) = *it.kind &&
-                            let clean::ImportKind::Simple(s) = i.kind { Some(s) } else { None }
-                    })
-                    .is_some()
-        })
-        .map(|it| item_ty_to_section(it.type_()))
-        .collect();
     for &sec in ItemSection::ALL.iter().filter(|sec| item_sections_in_use.contains(sec)) {
         let _ = write!(sidebar, "<li><a href=\"#{}\">{}</a></li>", sec.id(), sec.name());
     }
@@ -2657,6 +2686,25 @@ fn sidebar_module(buf: &mut Buffer, items: &[clean::Item]) {
     }
 }
 
+fn sidebar_module(buf: &mut Buffer, items: &[clean::Item]) {
+    let item_sections_in_use: FxHashSet<_> = items
+        .iter()
+        .filter(|it| {
+            !it.is_stripped()
+                && it
+                    .name
+                    .or_else(|| {
+                        if let clean::ImportItem(ref i) = *it.kind &&
+                            let clean::ImportKind::Simple(s) = i.kind { Some(s) } else { None }
+                    })
+                    .is_some()
+        })
+        .map(|it| item_ty_to_section(it.type_()))
+        .collect();
+
+    sidebar_module_like(buf, item_sections_in_use);
+}
+
 fn sidebar_foreign_type(cx: &Context<'_>, buf: &mut Buffer, it: &clean::Item) {
     let mut sidebar = Buffer::new();
     sidebar_assoc_items(cx, &mut sidebar, it);
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index d63d4c2d159b..3e324bbb069c 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -514,7 +514,7 @@ fn item_function(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, f: &cle
         + name.as_str().len()
         + generics_len;
 
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "fn", |w| {
             render_attributes_in_pre(w, it, "");
             w.reserve(header_len);
@@ -553,7 +553,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
         cx.tcx().trait_def(t.def_id).must_implement_one_of.clone();
 
     // Output the trait definition
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "trait", |w| {
             render_attributes_in_pre(w, it, "");
             write!(
@@ -1033,7 +1033,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
 }
 
 fn item_trait_alias(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::TraitAlias) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "trait-alias", |w| {
             render_attributes_in_pre(w, it, "");
             write!(
@@ -1057,7 +1057,7 @@ fn item_trait_alias(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &
 }
 
 fn item_opaque_ty(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::OpaqueTy) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "opaque", |w| {
             render_attributes_in_pre(w, it, "");
             write!(
@@ -1096,7 +1096,7 @@ fn item_typedef(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clea
         });
     }
 
-    wrap_into_docblock(w, |w| write_content(w, cx, it, t));
+    wrap_into_item_decl(w, |w| write_content(w, cx, it, t));
 
     document(w, cx, it, None, HeadingOffset::H2);
 
@@ -1110,7 +1110,7 @@ fn item_typedef(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clea
 }
 
 fn item_union(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Union) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "union", |w| {
             render_attributes_in_pre(w, it, "");
             render_union(w, it, Some(&s.generics), &s.fields, "", cx);
@@ -1174,7 +1174,7 @@ fn print_tuple_struct_fields(w: &mut Buffer, cx: &Context<'_>, s: &[clean::Item]
 
 fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::Enum) {
     let count_variants = e.variants().count();
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "enum", |w| {
             render_attributes_in_pre(w, it, "");
             write!(
@@ -1203,7 +1203,8 @@ fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::
                     let name = v.name.unwrap();
                     match *v.kind {
                         clean::VariantItem(ref var) => match var {
-                            clean::Variant::CLike => write!(w, "{}", name),
+                            // FIXME(#101337): Show discriminant
+                            clean::Variant::CLike(..) => write!(w, "{}", name),
                             clean::Variant::Tuple(ref s) => {
                                 write!(w, "{}(", name);
                                 print_tuple_struct_fields(w, cx, s);
@@ -1332,14 +1333,14 @@ fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::
 }
 
 fn item_macro(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::Macro) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         highlight::render_macro_with_highlighting(&t.source, w);
     });
     document(w, cx, it, None, HeadingOffset::H2)
 }
 
 fn item_proc_macro(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, m: &clean::ProcMacro) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         let name = it.name.expect("proc-macros always have names");
         match m.kind {
             MacroKind::Bang => {
@@ -1386,7 +1387,7 @@ fn item_primitive(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
 }
 
 fn item_constant(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, c: &clean::Constant) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "const", |w| {
             render_attributes_in_code(w, it);
 
@@ -1435,7 +1436,7 @@ fn item_constant(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, c: &cle
 }
 
 fn item_struct(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Struct) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "struct", |w| {
             render_attributes_in_code(w, it);
             render_struct(w, it, Some(&s.generics), s.struct_type, &s.fields, "", true, cx);
@@ -1488,7 +1489,7 @@ fn item_struct(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean
 }
 
 fn item_static(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Static) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "static", |w| {
             render_attributes_in_code(w, it);
             write!(
@@ -1505,7 +1506,7 @@ fn item_static(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean
 }
 
 fn item_foreign_type(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
-    wrap_into_docblock(w, |w| {
+    wrap_into_item_decl(w, |w| {
         wrap_item(w, "foreigntype", |w| {
             w.write_str("extern {\n");
             render_attributes_in_code(w, it);
@@ -1594,11 +1595,11 @@ fn bounds(t_bounds: &[clean::GenericBound], trait_alias: bool, cx: &Context<'_>)
     bounds
 }
 
-fn wrap_into_docblock<F>(w: &mut Buffer, f: F)
+fn wrap_into_item_decl<F>(w: &mut Buffer, f: F)
 where
     F: FnOnce(&mut Buffer),
 {
-    w.write_str("<div class=\"docblock item-decl\">");
+    w.write_str("<div class=\"item-decl\">");
     f(w);
     w.write_str("</div>")
 }
diff --git a/src/librustdoc/html/render/span_map.rs b/src/librustdoc/html/render/span_map.rs
index 34d590fb2448..151ec2b28adc 100644
--- a/src/librustdoc/html/render/span_map.rs
+++ b/src/librustdoc/html/render/span_map.rs
@@ -166,25 +166,23 @@ impl<'tcx> Visitor<'tcx> for SpanMapVisitor<'tcx> {
 
     fn visit_expr(&mut self, expr: &'tcx rustc_hir::Expr<'tcx>) {
         if let ExprKind::MethodCall(segment, ..) = expr.kind {
-            if let Some(hir_id) = segment.hir_id {
-                let hir = self.tcx.hir();
-                let body_id = hir.enclosing_body_owner(hir_id);
-                // FIXME: this is showing error messages for parts of the code that are not
-                // compiled (because of cfg)!
-                //
-                // See discussion in https://github.com/rust-lang/rust/issues/69426#issuecomment-1019412352
-                let typeck_results = self.tcx.typeck_body(
-                    hir.maybe_body_owned_by(body_id).expect("a body which isn't a body"),
+            let hir = self.tcx.hir();
+            let body_id = hir.enclosing_body_owner(segment.hir_id);
+            // FIXME: this is showing error messages for parts of the code that are not
+            // compiled (because of cfg)!
+            //
+            // See discussion in https://github.com/rust-lang/rust/issues/69426#issuecomment-1019412352
+            let typeck_results = self
+                .tcx
+                .typeck_body(hir.maybe_body_owned_by(body_id).expect("a body which isn't a body"));
+            if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
+                self.matches.insert(
+                    segment.ident.span,
+                    match hir.span_if_local(def_id) {
+                        Some(span) => LinkFromSrc::Local(clean::Span::new(span)),
+                        None => LinkFromSrc::External(def_id),
+                    },
                 );
-                if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
-                    self.matches.insert(
-                        segment.ident.span,
-                        match hir.span_if_local(def_id) {
-                            Some(span) => LinkFromSrc::Local(clean::Span::new(span)),
-                            None => LinkFromSrc::External(def_id),
-                        },
-                    );
-                }
             }
         } else if self.handle_macro(expr.span) {
             // We don't want to go deeper into the macro.
diff --git a/src/librustdoc/html/render/write_shared.rs b/src/librustdoc/html/render/write_shared.rs
index f9abb46207d7..1c88528aa20a 100644
--- a/src/librustdoc/html/render/write_shared.rs
+++ b/src/librustdoc/html/render/write_shared.rs
@@ -312,7 +312,7 @@ pub(super) fn write_shared(
                 if line.starts_with(&prefix) {
                     continue;
                 }
-                if line.ends_with(",") {
+                if line.ends_with(',') {
                     ret.push(line[..line.len() - 1].to_string());
                 } else {
                     // No comma (it's the case for the last added crate line)
@@ -519,12 +519,12 @@ if (typeof exports !== 'undefined') {exports.searchIndex = searchIndex};
             let content = format!(
                 "<h1 class=\"fqn\">\
                      <span class=\"in-band\">List of all crates</span>\
-                </h1><ul class=\"crate mod\">{}</ul>",
+                </h1><ul class=\"all-items\">{}</ul>",
                 krates
                     .iter()
                     .map(|s| {
                         format!(
-                            "<li><a class=\"crate mod\" href=\"{}index.html\">{}</a></li>",
+                            "<li><a href=\"{}index.html\">{}</a></li>",
                             ensure_trailing_slash(s),
                             s
                         )
diff --git a/src/librustdoc/html/sources.rs b/src/librustdoc/html/sources.rs
index f37c54e42983..2e2bee78b95f 100644
--- a/src/librustdoc/html/sources.rs
+++ b/src/librustdoc/html/sources.rs
@@ -288,11 +288,14 @@ pub(crate) fn print_src(
         }
     }
     line_numbers.write_str("</pre>");
+    let current_href = &context
+        .href_from_span(clean::Span::new(file_span), false)
+        .expect("only local crates should have sources emitted");
     highlight::render_source_with_highlighting(
         s,
         buf,
         line_numbers,
-        highlight::HrefContext { context, file_span, root_path },
+        highlight::HrefContext { context, file_span, root_path, current_href },
         decoration_info,
     );
 }
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index c117e3ac40da..28dc4bf30108 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -141,10 +141,6 @@ h1, h2, h3, h4 {
 h1.fqn {
 	margin: 0;
 	padding: 0;
-	border-bottom-color: var(--headings-border-bottom-color);
-}
-h2, h3, h4 {
-	border-bottom-color: var(--headings-border-bottom-color);
 }
 .main-heading {
 	display: flex;
@@ -180,8 +176,8 @@ h4.code-header {
 	border-bottom-style: none;
 	margin: 0;
 	padding: 0;
-	margin-top: 0.6em;
-	margin-bottom: 0.4em;
+	margin-top: 0.6rem;
+	margin-bottom: 0.4rem;
 }
 .impl,
 .impl-items .method,
@@ -197,26 +193,17 @@ h4.code-header {
 	position: relative;
 }
 
-div.impl-items > div {
-	padding-left: 0;
-}
-
 h1, h2, h3, h4, h5, h6,
 .sidebar,
 .mobile-topbar,
 a.source,
 .search-input,
 .search-results .result-name,
-.content table td:first-child > a,
 .item-left > a,
 .out-of-band,
 span.since,
-#source-sidebar, #sidebar-toggle,
 details.rustdoc-toggle > summary::before,
-div.impl-items > div:not(.docblock):not(.item-info),
-.content ul.crate a.crate,
 a.srclink,
-#main-content > .since,
 #help-button > button,
 details.rustdoc-toggle.top-doc > summary,
 details.rustdoc-toggle.top-doc > summary::before,
@@ -226,11 +213,10 @@ details.rustdoc-toggle.non-exhaustive > summary::before,
 .more-examples-toggle summary, .more-examples-toggle .hide-more,
 .example-links a,
 /* This selector is for the items listed in the "all items" page. */
-#main-content > ul.docblock > li > a {
+ul.all-items {
 	font-family: "Fira Sans", Arial, NanumBarunGothic, sans-serif;
 }
 
-h1, h2, h3, h4,
 a#toggle-all-docs,
 a.anchor,
 .small-section-header a,
@@ -250,6 +236,49 @@ pre.rust a,
 	color: var(--main-color);
 }
 
+.content span.enum, .content a.enum,
+.content span.struct, .content a.struct,
+.content span.union, .content a.union,
+.content span.primitive, .content a.primitive,
+.content span.type, .content a.type,
+.content span.foreigntype, .content a.foreigntype {
+	color: var(--type-link-color);
+}
+
+.content span.trait, .content a.trait,
+.content span.traitalias, .content a.traitalias {
+	color: var(--trait-link-color);
+}
+
+.content span.associatedtype, .content a.associatedtype,
+.content span.constant, .content a.constant,
+.content span.static, .content a.static {
+	color: var(--assoc-item-link-color);
+}
+
+.content span.fn, .content a.fn,
+.content .fnname {
+	color: var(--function-link-color);
+}
+
+.content span.attr, .content a.attr,
+.content span.derive, .content a.derive,
+.content span.macro, .content a.macro {
+	color: var(--macro-link-color);
+}
+
+.content span.mod, .content a.mod, .block a.current.mod {
+	color: var(--mod-link-color);
+}
+
+.content span.keyword, .content a.keyword {
+	color: var(--keyword-link-color);
+}
+
+a {
+	color: var(--link-color);
+}
+
 ol, ul {
 	padding-left: 24px;
 }
@@ -339,9 +368,6 @@ code, pre, a.test-arrow, .code-header {
 pre {
 	padding: 14px;
 }
-.docblock.item-decl {
-	margin-left: 0;
-}
 .item-decl pre {
 	overflow-x: auto;
 }
@@ -354,14 +380,8 @@ img {
 	max-width: 100%;
 }
 
-li {
-	position: relative;
-}
-
 .source .content {
-	max-width: none;
 	overflow: visible;
-	margin-left: 0px;
 }
 
 .sub-container {
@@ -391,7 +411,7 @@ li {
 
 .sidebar {
 	font-size: 0.875rem;
-	width: 250px;
+	width: 200px;
 	min-width: 200px;
 	overflow-y: scroll;
 	position: sticky;
@@ -502,17 +522,6 @@ li {
 	width: 100px;
 }
 
-.location:empty {
-	border: none;
-}
-
-.location a:first-of-type {
-	font-weight: 500;
-}
-
-.block {
-	padding: 0;
-}
 .block ul, .block li {
 	padding: 0;
 	margin: 0;
@@ -564,13 +573,9 @@ h2.location a {
 }
 
 .rustdoc .example-wrap {
-	display: inline-flex;
+	display: flex;
 	margin-bottom: 10px;
-}
-
-.example-wrap {
 	position: relative;
-	width: 100%;
 }
 
 .example-wrap > pre.line-number {
@@ -603,19 +608,10 @@ h2.location a {
 	margin: 0;
 }
 
-#search {
-	position: relative;
-}
-
 .search-loading {
 	text-align: center;
 }
 
-#results > table {
-	width: 100%;
-	table-layout: fixed;
-}
-
 .content > .example-wrap pre.line-numbers {
 	position: relative;
 	-webkit-user-select: none;
@@ -630,16 +626,12 @@ h2.location a {
 .docblock-short {
 	overflow-wrap: break-word;
 	overflow-wrap: anywhere;
-}
-.docblock-short p {
-	display: inline;
 	overflow: hidden;
 	text-overflow: ellipsis;
-	margin: 0;
 }
 /* Wrap non-pre code blocks (`text`) but not (```text```). */
 .docblock > :not(pre) > code,
-.docblock-short > :not(pre) > code {
+.docblock-short > code {
 	white-space: pre-wrap;
 }
 
@@ -655,33 +647,28 @@ h2.location a {
 
 .docblock h5 { font-size: 1rem; }
 .docblock h6 { font-size: 0.875rem; }
-.docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5, .docblock h6 {
-	border-bottom-color: var(--headings-border-bottom-color);
-}
 
 .docblock {
 	margin-left: 24px;
 	position: relative;
 }
 
-.docblock > :not(.information):not(.more-examples-toggle) {
+.docblock > :not(.more-examples-toggle):not(.example-wrap) {
 	max-width: 100%;
 	overflow-x: auto;
 }
 
-.content .out-of-band {
+.out-of-band {
 	flex-grow: 0;
 	font-size: 1.125rem;
 	font-weight: normal;
-	float: right;
 }
 
 .method > .code-header, .trait-impl > .code-header {
-	max-width: calc(100% - 41px);
 	display: block;
 }
 
-.content .in-band {
+.in-band {
 	flex-grow: 1;
 	margin: 0px;
 	padding: 0px;
@@ -694,10 +681,6 @@ h2.location a {
 	background-color: var(--main-background-color);
 }
 
-.in-band > code, .in-band > .code-header {
-	display: inline-block;
-}
-
 .docblock code, .docblock-short code,
 pre, .rustdoc.source .example-wrap {
 	background-color: var(--code-block-background-color);
@@ -706,18 +689,6 @@ pre, .rustdoc.source .example-wrap {
 #main-content {
 	position: relative;
 }
-#main-content > .since {
-	top: inherit;
-}
-
-.content table {
-	border-spacing: 0 5px;
-}
-.content td { vertical-align: top; }
-.content td:first-child { padding-right: 20px; }
-.content td p:first-child { margin-top: 0; }
-.content td h1, .content td h2 { margin-left: 0; font-size: 1.125rem; }
-.content tr:first-child td { border-top: 0; }
 
 .docblock table {
 	margin: .5em 0;
@@ -729,6 +700,7 @@ pre, .rustdoc.source .example-wrap {
 .docblock table td {
 	padding: .5em;
 	border: 1px dashed var(--border-color);
+	vertical-align: top;
 }
 
 .docblock table th {
@@ -742,10 +714,6 @@ pre, .rustdoc.source .example-wrap {
 	padding: 0;
 }
 
-.content > .methods > .method {
-	font-size: 1rem;
-	position: relative;
-}
 /* Shift "where ..." part of method or fn definition down a line */
 .content .method .where,
 .content .fn .where,
@@ -754,19 +722,6 @@ pre, .rustdoc.source .example-wrap {
 	font-size: 0.875rem;
 }
 
-.content .methods > div:not(.notable-traits):not(.method) {
-	margin-left: 40px;
-	margin-bottom: 15px;
-}
-
-.content .docblock > .impl-items {
-	margin-left: 20px;
-	margin-top: -34px;
-}
-.content .docblock >.impl-items table td {
-	padding: 0;
-}
-
 .item-info {
 	display: block;
 }
@@ -776,30 +731,13 @@ pre, .rustdoc.source .example-wrap {
 }
 
 .content .item-info {
-	position: relative;
 	margin-left: 24px;
 }
 
-.sub-variant > div > .item-info {
-	margin-top: initial;
-}
-
 .content .impl-items .docblock, .content .impl-items .item-info {
 	margin-bottom: .6em;
 }
 
-.content .impl-items > .item-info {
-	margin-left: 40px;
-}
-
-.methods > .item-info, .content .impl-items > .item-info {
-	margin-top: -8px;
-}
-
-.impl-items {
-	flex-basis: 100%;
-}
-
 #main-content > .item-info {
 	margin-top: 0;
 	margin-left: 0;
@@ -819,7 +757,6 @@ nav.sub form { display: inline; }
 
 a {
 	text-decoration: none;
-	background: transparent;
 }
 
 .small-section-header {
@@ -858,6 +795,7 @@ h2.small-section-header > .anchor {
 	content: '§';
 }
 
+.all-items a:hover,
 .docblock a:not(.srclink):not(.test-arrow):not(.scrape-help):hover,
 .docblock-short a:not(.srclink):not(.test-arrow):not(.scrape-help):hover, .item-info a {
 	text-decoration: underline;
@@ -997,6 +935,9 @@ so that we can apply CSS-filters to change the arrow color in themes */
 	width: 100%;
 	background-color: var(--button-background-color);
 }
+.search-input:focus {
+	border-color: var(--search-input-focused-border-color);
+}
 
 .search-results {
 	display: none;
@@ -1018,7 +959,6 @@ so that we can apply CSS-filters to change the arrow color in themes */
 
 .search-results > a {
 	display: block;
-	width: 100%;
 	/* A little margin ensures the browser's outlining of focused links has room to display. */
 	margin-left: 2px;
 	margin-right: 2px;
@@ -1037,12 +977,6 @@ so that we can apply CSS-filters to change the arrow color in themes */
 	padding-right: 1em;
 }
 
-.search-results .result-name > span {
-	display: inline-block;
-	margin: 0;
-	font-weight: normal;
-}
-
 .popover {
 	font-size: 1rem;
 	position: absolute;
@@ -1129,16 +1063,18 @@ so that we can apply CSS-filters to change the arrow color in themes */
 	font-size: 0.875rem;
 	font-weight: normal;
 }
-.stab p {
-	display: inline;
-	margin: 0;
-}
 
 .stab .emoji {
 	font-size: 1.25rem;
 	margin-right: 0.3rem;
 }
 
+/* This is to prevent the `.stab` elements to overflow the .docblock elements. */
+.docblock .stab {
+	padding: 0 0.125em;
+	margin-bottom: 0;
+}
+
 /* Black one-pixel outline around emoji shapes */
 .emoji {
 	text-shadow:
@@ -1177,24 +1113,116 @@ so that we can apply CSS-filters to change the arrow color in themes */
 	float: right;
 }
 
+.rightside:not(a),
+.out-of-band {
+	color: var(--right-side-color);
+}
+
+
 .impl-items .srclink, .impl .srclink, .methods .srclink {
 	/* Override header settings otherwise it's too bold */
 	font-weight: normal;
 	font-size: 1rem;
 }
 
-td.summary-column {
-	width: 100%;
-}
-
-.summary {
-	padding-right: 0px;
-}
-
 pre.rust .question-mark {
 	font-weight: bold;
 }
 
+.example-wrap.compile_fail,
+.example-wrap.should_panic {
+	border-left: 2px solid var(--codeblock-error-color);
+}
+
+.ignore.example-wrap {
+	border-left: 2px solid var(--codeblock-ignore-color);
+}
+
+.example-wrap.compile_fail:hover,
+.example-wrap.should_panic:hover {
+	border-left: 2px solid var(--codeblock-error-hover-color);
+}
+
+.example-wrap.ignore:hover {
+	border-left: 2px solid var(--codeblock-ignore-hover-color);
+}
+
+.example-wrap.compile_fail .tooltip,
+.example-wrap.should_panic .tooltip {
+	color: var(--codeblock-error-color);
+}
+
+.example-wrap.ignore .tooltip {
+	color:  var(--codeblock-ignore-color);
+}
+
+.example-wrap.compile_fail:hover .tooltip,
+.example-wrap.should_panic:hover .tooltip {
+	color: var(--codeblock-error-hover-color);
+}
+
+.example-wrap.ignore:hover .tooltip {
+	color: var(--codeblock-ignore-hover-color);
+}
+
+.example-wrap .tooltip {
+	position: absolute;
+	display: block;
+	cursor: pointer;
+	left: -25px;
+	top: 5px;
+}
+
+.example-wrap .tooltip::after {
+	display: none;
+	text-align: center;
+	padding: 5px 3px 3px 3px;
+	border-radius: 6px;
+	margin-left: 5px;
+	font-size: 1rem;
+	border: 1px solid var(--border-color);
+	position: absolute;
+	width: max-content;
+	top: -2px;
+	z-index: 1;
+}
+
+.example-wrap .tooltip::before {
+	content: " ";
+	position: absolute;
+	top: 50%;
+	left: 16px;
+	margin-top: -5px;
+	border-width: 5px;
+	border-style: solid;
+	display: none;
+	z-index: 1;
+}
+
+.example-wrap.ignore .tooltip::after {
+	content: "This example is not tested";
+}
+.example-wrap.compile_fail .tooltip::after {
+	content: "This example deliberately fails to compile";
+}
+.example-wrap.should_panic .tooltip::after {
+	content: "This example panics";
+}
+.example-wrap.edition .tooltip::after {
+	content: "This code runs with edition " attr(data-edition);
+}
+
+.example-wrap .tooltip:hover::before, .example-wrap .tooltip:hover::after {
+	display: inline;
+}
+
+.example-wrap.compile_fail .tooltip,
+.example-wrap.should_panic .tooltip,
+.example-wrap.ignore .tooltip {
+	font-weight: bold;
+	font-size: 1.25rem;
+}
+
 a.test-arrow {
 	display: inline-block;
 	visibility: hidden;
@@ -1215,6 +1243,7 @@ a.test-arrow:hover {
 
 .code-attribute {
 	font-weight: 300;
+	color: var(--code-attribute-color);
 }
 
 .item-spacer {
@@ -1223,7 +1252,6 @@ a.test-arrow:hover {
 }
 
 .out-of-band > span.since {
-	position: initial;
 	font-size: 1.25rem;
 }
 
@@ -1251,12 +1279,6 @@ h3.variant {
 	margin-left: 24px;
 }
 
-.toggle-label {
-	display: inline-block;
-	margin-left: 4px;
-	margin-top: 3px;
-}
-
 :target > code, :target > .code-header {
 	opacity: 1;
 }
@@ -1265,62 +1287,6 @@ h3.variant {
 	padding-right: 3px;
 }
 
-.information {
-	position: absolute;
-	left: -25px;
-	margin-top: 7px;
-	z-index: 1;
-}
-
-.tooltip {
-	position: relative;
-	display: inline-block;
-	cursor: pointer;
-}
-
-.tooltip::after {
-	display: none;
-	text-align: center;
-	padding: 5px 3px 3px 3px;
-	border-radius: 6px;
-	margin-left: 5px;
-	font-size: 1rem;
-	border: 1px solid var(--border-color);
-}
-
-.tooltip.ignore::after {
-	content: "This example is not tested";
-}
-.tooltip.compile_fail::after {
-	content: "This example deliberately fails to compile";
-}
-.tooltip.should_panic::after {
-	content: "This example panics";
-}
-.tooltip.edition::after {
-	content: "This code runs with edition " attr(data-edition);
-}
-
-.tooltip::before {
-	content: " ";
-	position: absolute;
-	top: 50%;
-	left: 16px;
-	margin-top: -5px;
-	border-width: 5px;
-	border-style: solid;
-	display: none;
-}
-
-.tooltip:hover::before, .tooltip:hover::after {
-	display: inline;
-}
-
-.tooltip.compile_fail, .tooltip.should_panic, .tooltip.ignore {
-	font-weight: bold;
-	font-size: 1.25rem;
-}
-
 .notable-traits-tooltip {
 	display: inline-block;
 	cursor: pointer;
@@ -1362,7 +1328,7 @@ h3.variant {
 	display: block;
 }
 
-.notable-traits .docblock code.content{
+.notable-traits .docblock code.content {
 	margin: 0;
 	padding: 0;
 	font-size: 1.25rem;
@@ -1396,27 +1362,19 @@ pre.rust {
 }
 
 #titles {
-	height: 35px;
+	display: flex;
+	flex-direction: row;
+	gap: 1px;
+	margin-bottom: 4px;
 }
 
 #titles > button {
-	float: left;
-	width: 33.3%;
 	text-align: center;
 	font-size: 1.125rem;
 	cursor: pointer;
 	border: 0;
 	border-top: 2px solid;
-}
-
-#titles > button:first-child:last-child {
-	margin-right: 1px;
-	width: calc(100% - 1px);
-}
-
-#titles > button:not(:last-child) {
-	margin-right: 1px;
-	width: calc(33.3% - 1px);
+	flex: 1;
 }
 
 #titles > button > div.count {
@@ -1445,7 +1403,6 @@ pre.rust {
 }
 #source-sidebar {
 	width: 100%;
-	z-index: 1;
 	overflow: auto;
 }
 #source-sidebar > .title {
@@ -1484,9 +1441,7 @@ pre.rust {
 	border-radius: 2px;
 	cursor: pointer;
 }
-#settings-menu {
-	padding: 0;
-}
+
 #settings-menu > a, #help-button > button {
 	padding: 5px;
 	height: 100%;
@@ -1494,6 +1449,16 @@ pre.rust {
 	background-color: var(--button-background-color);
 }
 
+#copy-path {
+	color: var(--copy-path-button-color);
+}
+#copy-path > img {
+	filter: var(--copy-path-img-filter);
+}
+#copy-path:hover > img {
+	filter: var(--copy-path-img-hover-filter);
+}
+
 @keyframes rotating {
 	from {
 		transform: rotate(0deg);
@@ -1553,21 +1518,10 @@ kbd {
 	cursor: default;
 }
 
-#implementations-list > h3 > span.in-band {
-	width: 100%;
-}
-
-#main-content > ul {
-	padding-left: 10px;
-}
-#main-content > ul > li {
+ul.all-items > li {
 	list-style: none;
 }
 
-.non-exhaustive {
-	margin-bottom: 1em;
-}
-
 details.dir-entry {
 	padding-left: 4px;
 }
@@ -1617,6 +1571,12 @@ details.rustdoc-toggle > summary::before {
 	opacity: .5;
 }
 
+details.rustdoc-toggle > summary.hideme > span,
+details.rustdoc-toggle > summary::before,
+.more-examples-toggle summary, .more-examples-toggle .hide-more {
+	color: var(--toggles-color);
+}
+
 /* Screen readers see the text version at the end the line.
 	Visual readers see the icon at the start of the line, but small and transparent. */
 details.rustdoc-toggle > summary::after {
@@ -1721,7 +1681,7 @@ in storage.js plus the media query with (max-width: 700px)
 	to prevent an overlay between the "collapse toggle" and the information tooltip.
 	However, it's not needed with smaller screen width because the doc/code block is always put
 	"one line" below. */
-	.docblock > .information:first-child > .tooltip {
+	.docblock > .example-wrap:first-child .tooltip {
 		margin-top: 16px;
 	}
 
@@ -1762,18 +1722,17 @@ in storage.js plus the media query with (min-width: 701px)
 		padding-top: 0px;
 	}
 
-	.rustdoc,
 	.main-heading {
 		flex-direction: column;
 	}
 
-	.content .out-of-band {
+	.out-of-band {
 		text-align: left;
 		margin-left: initial;
 		padding: initial;
 	}
 
-	.content .out-of-band .since::before {
+	.out-of-band .since::before {
 		content: "Since ";
 	}
 
@@ -1885,10 +1844,6 @@ in storage.js plus the media query with (min-width: 701px)
 		background-color: var(--sidebar-background-color);
 	}
 
-	.source nav:not(.sidebar).sub {
-		margin-left: 32px;
-	}
-
 	.content {
 		margin-left: 0px;
 	}
@@ -1897,28 +1852,12 @@ in storage.js plus the media query with (min-width: 701px)
 		margin-top: 10px;
 	}
 
-	#search {
-		margin-left: 0;
-		padding: 0;
-	}
-
 	.anchor {
 		display: none !important;
 	}
 
-	.notable-traits {
-		position: absolute;
-		left: -22px;
-		top: 24px;
-	}
-
 	#titles > button > div.count {
-		float: left;
-		width: 100%;
-	}
-
-	#titles {
-		height: 50px;
+		display: block;
 	}
 
 	/* Because of ios, we need to actually have a full height sidebar title so the
@@ -1969,14 +1908,6 @@ in storage.js plus the media query with (min-width: 701px)
 		border-bottom: 1px solid;
 	}
 
-	#source-sidebar {
-		z-index: 11;
-	}
-
-	#main-content > .line-numbers {
-		margin-top: 0;
-	}
-
 	.notable-traits .notable-traits-tooltiptext {
 		left: 0;
 		top: 100%;
@@ -2025,10 +1956,15 @@ in storage.js plus the media query with (min-width: 701px)
 	#main-content > div > details.rustdoc-toggle > summary::before {
 		left: -11px;
 	}
+
+	/* Align summary-nested and unnested item-info gizmos. */
+	.content .impl-items > .item-info {
+		margin-left: 34px;
+	}
 }
 
 @media print {
-	nav.sidebar, nav.sub, .content .out-of-band, a.srclink, #copy-path,
+	nav.sidebar, nav.sub, .out-of-band, a.srclink, #copy-path,
 	details.rustdoc-toggle[open] > summary::before, details.rustdoc-toggle > summary::before,
 	details.rustdoc-toggle.top-doc > summary {
 		display: none;
@@ -2044,15 +1980,6 @@ in storage.js plus the media query with (min-width: 701px)
 }
 
 @media (max-width: 464px) {
-	#titles, #titles > button {
-		height: 73px;
-	}
-
-	#main-content > table td {
-		word-break: break-word;
-		width: 50%;
-	}
-
 	#crate-search {
 		border-radius: 4px;
 	}
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index e301a793282e..e7a898e9fa62 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -16,6 +16,25 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--headings-border-bottom-color: #5c6773;
 	--border-color: #5c6773;
 	--button-background-color: #141920;
+	--right-side-color: grey;
+	--code-attribute-color: #999;
+	--toggles-color: #999;
+	--search-input-focused-border-color: #5c6773; /* Same as `--border-color`. */
+	--copy-path-button-color: #fff;
+	--copy-path-img-filter: invert(70%);
+	--copy-path-img-hover-filter: invert(100%);
+	--codeblock-error-hover-color: rgb(255, 0, 0);
+	--codeblock-error-color: rgba(255, 0, 0, .5);
+	--codeblock-ignore-hover-color: rgb(255, 142, 0);
+	--codeblock-ignore-color: rgba(255, 142, 0, .6);
+	--type-link-color: #ffa0a5;
+	--trait-link-color: #39afd7;
+	--assoc-item-link-color: #39afd7;
+	--function-link-color: #fdd687;
+	--macro-link-color: #a37acc;
+	--keyword-link-color: #39afd7;
+	--mod-link-color: #39afd7;
+	--link-color: #39afd7;
 }
 
 .slider {
@@ -100,56 +119,12 @@ pre, .rustdoc.source .example-wrap {
 
 .content .item-info::before { color: #ccc; }
 
-.content span.foreigntype, .content a.foreigntype { color: #ffa0a5; }
-.content span.union, .content a.union { color: #ffa0a5; }
-.content span.constant, .content a.constant,
-.content span.static, .content a.static { color: #39AFD7; }
-.content span.primitive, .content a.primitive { color: #ffa0a5; }
-.content span.traitalias, .content a.traitalias { color: #39AFD7; }
-.content span.keyword, .content a.keyword { color: #39AFD7; }
-
-.content span.externcrate, .content span.mod, .content a.mod {
-	color: #39AFD7;
-}
-.content span.struct, .content a.struct {
-	color: #ffa0a5;
-}
-.content span.enum, .content a.enum {
-	color: #ffa0a5;
-}
-.content span.trait, .content a.trait {
-	color: #39AFD7;
-}
-.content span.type, .content a.type {
-	color: #39AFD7;
-}
-.content span.type,
-.content a.type,
-.block a.current.type { color: #39AFD7; }
-.content span.associatedtype,
-.content a.associatedtype,
-.block a.current.associatedtype { color: #39AFD7; }
-.content span.fn, .content a.fn, .content span.method,
-.content a.method, .content span.tymethod,
-.content a.tymethod, .content .fnname {
-	color: #fdd687;
-}
-.content span.attr, .content a.attr, .content span.derive,
-.content a.derive, .content span.macro, .content a.macro {
-	color: #a37acc;
-}
-
 .sidebar a { color: #53b1db; }
 .sidebar a.current.type { color: #53b1db; }
-.sidebar a.current.associatedtype { color: #53b1db; }
 
 pre.rust .comment { color: #788797; }
 pre.rust .doccomment { color: #a1ac88; }
 
-a {
-	color: #39AFD7;
-}
-
 .sidebar h2 a,
 .sidebar h3 a {
 	color: white;
@@ -158,11 +133,6 @@ body.source .example-wrap pre.rust a {
 	background: #333;
 }
 
-details.rustdoc-toggle > summary.hideme > span,
-details.rustdoc-toggle > summary::before {
-	color: #999;
-}
-
 details.rustdoc-toggle > summary::before {
 	filter: invert(100%);
 }
@@ -197,11 +167,6 @@ details.rustdoc-toggle > summary::before {
 	background: none;
 }
 
-.rightside:not(a),
-.out-of-band {
-	color: grey;
-}
-
 .result-name .primitive > i, .result-name .keyword > i {
 	color: #788797;
 }
@@ -242,64 +207,11 @@ a.test-arrow:hover {
 	color: #c5c5c5;
 }
 
-.toggle-label,
-.code-attribute {
-	color: #999;
-}
-
 :target {
 	background: rgba(255, 236, 164, 0.06);
 	border-right: 3px solid rgba(255, 180, 76, 0.85);
 }
 
-pre.compile_fail {
-	border-left: 2px solid rgba(255,0,0,.4);
-}
-
-pre.compile_fail:hover, .information:hover + pre.compile_fail {
-	border-left: 2px solid #f00;
-}
-
-pre.should_panic {
-	border-left: 2px solid rgba(255,0,0,.4);
-}
-
-pre.should_panic:hover, .information:hover + pre.should_panic {
-	border-left: 2px solid #f00;
-}
-
-pre.ignore {
-	border-left: 2px solid rgba(255,142,0,.6);
-}
-
-pre.ignore:hover, .information:hover + pre.ignore {
-	border-left: 2px solid #ff9200;
-}
-
-.tooltip.compile_fail {
-	color: rgba(255,0,0,.5);
-}
-
-.information > .compile_fail:hover {
-	color: #f00;
-}
-
-.tooltip.should_panic {
-	color: rgba(255,0,0,.5);
-}
-
-.information > .should_panic:hover {
-	color: #f00;
-}
-
-.tooltip.ignore {
-	color: rgba(255,142,0,.6);
-}
-
-.information > .ignore:hover {
-	color: #ff9200;
-}
-
 .search-failed a {
 	color: #39AFD7;
 }
@@ -342,35 +254,11 @@ individually rather than as a group) */
 /* FIXME: these rules should be at the bottom of the file but currently must be
 above the `@media (max-width: 700px)` rules due to a bug in the css checker */
 /* see https://github.com/rust-lang/rust/pull/71237#issuecomment-618170143 */
-.search-input:focus {}
-.content span.attr,.content a.attr,.block a.current.attr,.content span.derive,.content a.derive,
-.block a.current.derive,.content span.macro,.content a.macro,.block a.current.macro {}
-.content span.struct,.content a.struct,.block a.current.struct {}
-#titles>button:hover,#titles>button.selected {}
-.content span.typedef,.content a.typedef,.block a.current.typedef {}
-.content span.union,.content a.union,.block a.current.union {}
 pre.rust .lifetime {}
-.stab.unstable {}
-h2,
-h3:not(.impl):not(.method):not(.type):not(.tymethod), h4:not(.method):not(.type):not(.tymethod) {}
-.content span.enum,.content a.enum,.block a.current.enum {}
-.content span.constant,.content a.constant,.block a.current.constant,.content span.static,
-.content a.static, .block a.current.static {}
-.content span.keyword,.content a.keyword,.block a.current.keyword {}
-.content span.traitalias,.content a.traitalias,.block a.current.traitalias {}
-.content span.fn,.content a.fn,.block a.current.fn,.content span.method,.content a.method,
-.block a.current.method,.content span.tymethod,.content a.tymethod,.block a.current.tymethod,
-.content .fnname {}
 pre.rust .kw {}
-pre.rust .self,pre.rust .bool-val,pre.rust .prelude-val,pre.rust .attribute {}
-.content span.foreigntype,.content a.foreigntype,.block a.current.foreigntype {}
-.stab.deprecated {}
-.content a.attr,.content a.derive,.content a.macro {}
-.stab.portability {}
-.content span.primitive,.content a.primitive,.block a.current.primitive {}
-.content span.externcrate,.content span.mod,.content a.mod,.block a.current.mod {}
-pre.rust .kw-2,pre.rust .prelude-ty {}
-.content span.trait,.content a.trait,.block a.current.trait {}
+#titles > button:hover, #titles > button.selected {}
+pre.rust .self, pre.rust .bool-val, pre.rust .prelude-val, pre.rust .attribute {}
+pre.rust .kw-2, pre.rust .prelude-ty {}
 
 .search-results a:focus span {}
 a.result-trait:focus {}
@@ -406,13 +294,9 @@ a.result-keyword:focus {}
 .sidebar a.current.constant
 .sidebar a.current.static {}
 .sidebar a.current.primitive {}
-.sidebar a.current.externcrate
-.sidebar a.current.mod {}
 .sidebar a.current.trait {}
 .sidebar a.current.traitalias {}
-.sidebar a.current.fn,
-.sidebar a.current.method,
-.sidebar a.current.tymethod {}
+.sidebar a.current.fn {}
 .sidebar a.current.keyword {}
 
 kbd {
@@ -429,16 +313,6 @@ kbd {
 	filter: invert(100);
 }
 
-#copy-path {
-	color: #fff;
-}
-#copy-path > img {
-	filter: invert(70%);
-}
-#copy-path:hover > img {
-	filter: invert(100%);
-}
-
 #settings-menu > a:hover, #settings-menu > a:focus,
 #help-button > button:hover, #help-button > button:focus {
 	border-color: #e0e0e0;
@@ -472,9 +346,6 @@ kbd {
 	border-color: white;
 	color: white;
 }
-.more-examples-toggle summary, .more-examples-toggle .hide-more {
-	color: #999;
-}
 .scraped-example .example-wrap .rust span.highlight {
 	background: rgb(91, 59, 1);
 }
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index d5cd47c3e19d..07a1ed8b7db7 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -11,6 +11,25 @@
 	--headings-border-bottom-color: #d2d2d2;
 	--border-color: #e0e0e0;
 	--button-background-color: #f0f0f0;
+	--right-side-color: grey;
+	--code-attribute-color: #999;
+	--toggles-color: #999;
+	--search-input-focused-border-color: #008dfd;
+	--copy-path-button-color: #999;
+	--copy-path-img-filter: invert(50%);
+	--copy-path-img-hover-filter: invert(65%);
+	--codeblock-error-hover-color: rgb(255, 0, 0);
+	--codeblock-error-color: rgba(255, 0, 0, .5);
+	--codeblock-ignore-hover-color: rgb(255, 142, 0);
+	--codeblock-ignore-color: rgba(255, 142, 0, .6);
+	--type-link-color: #2dbfb8;
+	--trait-link-color: #b78cf2;
+	--assoc-item-link-color: #d2991d;
+	--function-link-color: #2bab63;
+	--macro-link-color: #09bd00;
+	--keyword-link-color: #d2991d;
+	--mod-link-color:  #d2991d;
+	--link-color: #d2991d;
 }
 
 .slider {
@@ -72,35 +91,10 @@ a.result-keyword:focus { background-color: #884719; }
 
 .content .item-info::before { color: #ccc; }
 
-.content span.enum, .content a.enum, .block a.current.enum { color: #2dbfb8; }
-.content span.struct, .content a.struct, .block a.current.struct { color: #2dbfb8; }
-.content span.type, .content a.type, .block a.current.type { color: #2dbfb8; }
-.content span.associatedtype,
-.content a.associatedtype,
-.block a.current.associatedtype { color: #D2991D; }
-.content span.foreigntype, .content a.foreigntype, .block a.current.foreigntype { color: #2dbfb8; }
-.content span.attr, .content a.attr, .block a.current.attr,
-.content span.derive, .content a.derive, .block a.current.derive,
-.content span.macro, .content a.macro, .block a.current.macro { color: #09bd00; }
-.content span.union, .content a.union, .block a.current.union { color: #2dbfb8; }
-.content span.constant, .content a.constant, .block a.current.constant,
-.content span.static, .content a.static, .block a.current.static { color: #D2991D; }
-.content span.primitive, .content a.primitive, .block a.current.primitive { color: #2dbfb8; }
-.content span.externcrate,
-.content span.mod, .content a.mod, .block a.current.mod { color: #D2991D; }
-.content span.trait, .content a.trait, .block a.current.trait { color: #b78cf2; }
-.content span.traitalias, .content a.traitalias, .block a.current.traitalias { color: #b78cf2; }
-.content span.fn, .content a.fn, .block a.current.fn,
-.content span.method, .content a.method, .block a.current.method,
-.content span.tymethod, .content a.tymethod, .block a.current.tymethod,
-.content .fnname{ color: #2BAB63; }
-.content span.keyword, .content a.keyword, .block a.current.keyword { color: #D2991D; }
-
 .sidebar a { color: #fdbf35; }
 .sidebar a.current.enum { color: #12ece2; }
 .sidebar a.current.struct { color: #12ece2; }
 .sidebar a.current.type { color: #12ece2; }
-.sidebar a.current.associatedtype { color: #fdbf35; }
 .sidebar a.current.foreigntype { color: #12ece2; }
 .sidebar a.current.attr,
 .sidebar a.current.derive,
@@ -109,38 +103,24 @@ a.result-keyword:focus { background-color: #884719; }
 .sidebar a.current.constant
 .sidebar a.current.static { color: #fdbf35; }
 .sidebar a.current.primitive { color: #12ece2; }
-.sidebar a.current.externcrate
-.sidebar a.current.mod { color: #fdbf35; }
 .sidebar a.current.trait { color: #cca7ff; }
 .sidebar a.current.traitalias { color: #cca7ff; }
-.sidebar a.current.fn,
-.sidebar a.current.method,
-.sidebar a.current.tymethod { color: #32d479; }
+.sidebar a.current.fn { color: #32d479; }
 .sidebar a.current.keyword { color: #fdbf35; }
 
 pre.rust .comment { color: #8d8d8b; }
 pre.rust .doccomment { color: #8ca375; }
 
-a {
-	color: #D2991D;
-}
-
 body.source .example-wrap pre.rust a {
 	background: #333;
 }
 
-details.rustdoc-toggle > summary.hideme > span,
-details.rustdoc-toggle > summary::before {
-	color: #999;
-}
-
 details.rustdoc-toggle > summary::before {
 	filter: invert(100%);
 }
 
 .search-input {
 	color: #111;
-	border-color: #f0f0f0;
 }
 
 #crate-search-div::after {
@@ -154,10 +134,6 @@ details.rustdoc-toggle > summary::before {
 	filter: invert(69%) sepia(60%) saturate(6613%) hue-rotate(184deg) brightness(100%) contrast(91%);
 }
 
-.search-input:focus {
-	border-color: #008dfd;
-}
-
 .stab { background: #314559; }
 
 .stab.portability > code {
@@ -165,11 +141,6 @@ details.rustdoc-toggle > summary::before {
 	background: none;
 }
 
-.rightside:not(a),
-.out-of-band {
-	color: grey;
-}
-
 .line-numbers :target { background-color: transparent; }
 
 /* Code highlighting */
@@ -197,64 +168,11 @@ a.test-arrow:hover{
 	background-color: #4e8bca;
 }
 
-.toggle-label,
-.code-attribute {
-	color: #999;
-}
-
 :target {
 	background-color: #494a3d;
 	border-right: 3px solid #bb7410;
 }
 
-pre.compile_fail {
-	border-left: 2px solid rgba(255,0,0,.8);
-}
-
-pre.compile_fail:hover, .information:hover + pre.compile_fail {
-	border-left: 2px solid #f00;
-}
-
-pre.should_panic {
-	border-left: 2px solid rgba(255,0,0,.8);
-}
-
-pre.should_panic:hover, .information:hover + pre.should_panic {
-	border-left: 2px solid #f00;
-}
-
-pre.ignore {
-	border-left: 2px solid rgba(255,142,0,.6);
-}
-
-pre.ignore:hover, .information:hover + pre.ignore {
-	border-left: 2px solid #ff9200;
-}
-
-.tooltip.compile_fail {
-	color: rgba(255,0,0,.8);
-}
-
-.information > .compile_fail:hover {
-	color: #f00;
-}
-
-.tooltip.should_panic {
-	color: rgba(255,0,0,.8);
-}
-
-.information > .should_panic:hover {
-	color: #f00;
-}
-
-.tooltip.ignore {
-	color: rgba(255,142,0,.6);
-}
-
-.information > .ignore:hover {
-	color: #ff9200;
-}
-
 .search-failed a {
 	color: #0089ff;
 }
@@ -302,16 +220,6 @@ kbd {
 	border-color: #ffb900;
 }
 
-#copy-path {
-	color: #999;
-}
-#copy-path > img {
-	filter: invert(50%);
-}
-#copy-path:hover > img {
-	filter: invert(65%);
-}
-
 .search-results .result-name span.alias {
 	color: #fff;
 }
@@ -335,9 +243,6 @@ kbd {
 	border-color: white;
 	color: white;
 }
-.more-examples-toggle summary, .more-examples-toggle .hide-more {
-	color: #999;
-}
 .scraped-example .example-wrap .rust span.highlight {
 	background: rgb(91, 59, 1);
 }
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index cff70268144f..64335f629280 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -11,6 +11,25 @@
 	--headings-border-bottom-color: #ddd;
 	--border-color: #e0e0e0;
 	--button-background-color: #fff;
+	--right-side-color: grey;
+	--code-attribute-color: #999;
+	--toggles-color: #999;
+	--search-input-focused-border-color: #66afe9;
+	--copy-path-button-color: #999;
+	--copy-path-img-filter: invert(50%);
+	--copy-path-img-hover-filter: invert(35%);
+	--codeblock-error-hover-color: rgb(255, 0, 0);
+	--codeblock-error-color: rgba(255, 0, 0, .5);
+	--codeblock-ignore-hover-color: rgb(255, 142, 0);
+	--codeblock-ignore-color: rgba(255, 142, 0, .6);
+	--type-link-color: #ad378a;
+	--trait-link-color: #6e4fc9;
+	--assoc-item-link-color: #3873ad;
+	--function-link-color: #ad7c37;
+	--macro-link-color: #068000;
+	--keyword-link-color: #3873ad;
+	--mod-link-color: #3873ad;
+	--link-color: #3873ad;
 }
 
 .slider {
@@ -71,35 +90,10 @@ a.result-keyword:focus { background-color: #afc6e4; }
 
 .content .item-info::before { color: #ccc; }
 
-.content span.enum, .content a.enum, .block a.current.enum { color: #AD378A; }
-.content span.struct, .content a.struct, .block a.current.struct { color: #AD378A; }
-.content span.type, .content a.type, .block a.current.type { color:  #AD378A; }
-.content span.foreigntype, .content a.foreigntype, .block a.current.foreigntype { color: #3873AD; }
-.content span.associatedtype,
-.content a.associatedtype,
-.block a.current.associatedtype { color: #3873AD; }
-.content span.attr, .content a.attr, .block a.current.attr,
-.content span.derive, .content a.derive, .block a.current.derive,
-.content span.macro, .content a.macro, .block a.current.macro { color: #068000; }
-.content span.union, .content a.union, .block a.current.union { color: #AD378A; }
-.content span.constant, .content a.constant, .block a.current.constant,
-.content span.static, .content a.static, .block a.current.static { color: #3873AD; }
-.content span.primitive, .content a.primitive, .block a.current.primitive { color: #AD378A; }
-.content span.externcrate,
-.content span.mod, .content a.mod, .block a.current.mod { color: #3873AD; }
-.content span.trait, .content a.trait, .block a.current.trait { color: #6E4FC9; }
-.content span.traitalias, .content a.traitalias, .block a.current.traitalias { color: #5137AD; }
-.content span.fn, .content a.fn, .block a.current.fn,
-.content span.method, .content a.method, .block a.current.method,
-.content span.tymethod, .content a.tymethod, .block a.current.tymethod,
-.content .fnname { color: #AD7C37; }
-.content span.keyword, .content a.keyword, .block a.current.keyword { color: #3873AD; }
-
 .sidebar a { color: #356da4; }
 .sidebar a.current.enum { color: #a63283; }
 .sidebar a.current.struct { color: #a63283; }
 .sidebar a.current.type { color: #a63283; }
-.sidebar a.current.associatedtype { color: #356da4; }
 .sidebar a.current.foreigntype { color: #356da4; }
 .sidebar a.current.attr,
 .sidebar a.current.derive,
@@ -108,28 +102,15 @@ a.result-keyword:focus { background-color: #afc6e4; }
 .sidebar a.current.constant
 .sidebar a.current.static { color: #356da4; }
 .sidebar a.current.primitive { color: #a63283; }
-.sidebar a.current.externcrate
-.sidebar a.current.mod { color: #356da4; }
 .sidebar a.current.trait { color: #6849c3; }
 .sidebar a.current.traitalias { color: #4b349e; }
-.sidebar a.current.fn,
-.sidebar a.current.method,
-.sidebar a.current.tymethod { color: #a67736; }
+.sidebar a.current.fn { color: #a67736; }
 .sidebar a.current.keyword { color: #356da4; }
 
-a {
-	color: #3873AD;
-}
-
 body.source .example-wrap pre.rust a {
 	background: #eee;
 }
 
-details.rustdoc-toggle > summary.hideme > span,
-details.rustdoc-toggle > summary::before {
-	color: #999;
-}
-
 #crate-search-div::after {
 	/* match border-color; uses https://codepen.io/sosuke/pen/Pjoqqp */
 	filter: invert(100%) sepia(0%) saturate(4223%) hue-rotate(289deg) brightness(114%) contrast(76%);
@@ -141,18 +122,9 @@ details.rustdoc-toggle > summary::before {
 	filter: invert(44%) sepia(18%) saturate(23%) hue-rotate(317deg) brightness(96%) contrast(93%);
 }
 
-.search-input:focus {
-	border-color: #66afe9;
-}
-
 .stab { background: #FFF5D6; border-color: #FFC600; }
 .stab.portability > code { background: none; }
 
-.rightside:not(a),
-.out-of-band {
-	color: grey;
-}
-
 .line-numbers :target { background-color: transparent; }
 
 /* Code highlighting */
@@ -182,64 +154,11 @@ a.test-arrow:hover{
 	background-color: #4e8bca;
 }
 
-.toggle-label,
-.code-attribute {
-	color: #999;
-}
-
 :target {
 	background: #FDFFD3;
 	border-right: 3px solid #AD7C37;
 }
 
-pre.compile_fail {
-	border-left: 2px solid rgba(255,0,0,.5);
-}
-
-pre.compile_fail:hover, .information:hover + pre.compile_fail {
-	border-left: 2px solid #f00;
-}
-
-pre.should_panic {
-	border-left: 2px solid rgba(255,0,0,.5);
-}
-
-pre.should_panic:hover, .information:hover + pre.should_panic {
-	border-left: 2px solid #f00;
-}
-
-pre.ignore {
-	border-left: 2px solid rgba(255,142,0,.6);
-}
-
-pre.ignore:hover, .information:hover + pre.ignore {
-	border-left: 2px solid #ff9200;
-}
-
-.tooltip.compile_fail {
-	color: rgba(255,0,0,.5);
-}
-
-.information > .compile_fail:hover {
-	color: #f00;
-}
-
-.tooltip.should_panic {
-	color: rgba(255,0,0,.5);
-}
-
-.information > .should_panic:hover {
-	color: #f00;
-}
-
-.tooltip.ignore {
-	color: rgba(255,142,0,.6);
-}
-
-.information > .ignore:hover {
-	color: #ff9200;
-}
-
 .search-failed a {
 	color: #3873AD;
 }
@@ -282,16 +201,6 @@ kbd {
 	border-color: #717171;
 }
 
-#copy-path {
-	color: #999;
-}
-#copy-path > img {
-	filter: invert(50%);
-}
-#copy-path:hover > img {
-	filter: invert(35%);
-}
-
 .search-results .result-name span.alias {
 	color: #000;
 }
@@ -314,9 +223,6 @@ kbd {
 	border-color: black;
 	color: black;
 }
-.more-examples-toggle summary, .more-examples-toggle .hide-more {
-	color: #999;
-}
 .scraped-example .example-wrap .rust span.highlight {
 	background: #fcffd6;
 }
diff --git a/src/librustdoc/html/static/js/main.js b/src/librustdoc/html/static/js/main.js
index 7f61c95e794b..c9674f11a5ec 100644
--- a/src/librustdoc/html/static/js/main.js
+++ b/src/librustdoc/html/static/js/main.js
@@ -555,7 +555,6 @@ function loadCss(cssFileName) {
                 const code = document.createElement("h3");
                 code.innerHTML = struct[TEXT_IDX];
                 addClass(code, "code-header");
-                addClass(code, "in-band");
 
                 onEachLazy(code.getElementsByTagName("a"), elem => {
                     const href = elem.getAttribute("href");
@@ -697,40 +696,40 @@ function loadCss(cssFileName) {
         }
     }());
 
+    window.rustdoc_add_line_numbers_to_examples = () => {
+        onEachLazy(document.getElementsByClassName("rust-example-rendered"), x => {
+            const parent = x.parentNode;
+            const line_numbers = parent.querySelectorAll(".line-number");
+            if (line_numbers.length > 0) {
+                return;
+            }
+            const count = x.textContent.split("\n").length;
+            const elems = [];
+            for (let i = 0; i < count; ++i) {
+                elems.push(i + 1);
+            }
+            const node = document.createElement("pre");
+            addClass(node, "line-number");
+            node.innerHTML = elems.join("\n");
+            parent.insertBefore(node, x);
+        });
+    };
+
+    window.rustdoc_remove_line_numbers_from_examples = () => {
+        onEachLazy(document.getElementsByClassName("rust-example-rendered"), x => {
+            const parent = x.parentNode;
+            const line_numbers = parent.querySelectorAll(".line-number");
+            for (const node of line_numbers) {
+                parent.removeChild(node);
+            }
+        });
+    };
+
     (function() {
         // To avoid checking on "rustdoc-line-numbers" value on every loop...
-        let lineNumbersFunc = () => {};
         if (getSettingValue("line-numbers") === "true") {
-            lineNumbersFunc = x => {
-                const count = x.textContent.split("\n").length;
-                const elems = [];
-                for (let i = 0; i < count; ++i) {
-                    elems.push(i + 1);
-                }
-                const node = document.createElement("pre");
-                addClass(node, "line-number");
-                node.innerHTML = elems.join("\n");
-                x.parentNode.insertBefore(node, x);
-            };
+            window.rustdoc_add_line_numbers_to_examples();
         }
-        onEachLazy(document.getElementsByClassName("rust-example-rendered"), e => {
-            if (hasClass(e, "compile_fail")) {
-                e.addEventListener("mouseover", function() {
-                    this.parentElement.previousElementSibling.childNodes[0].style.color = "#f00";
-                });
-                e.addEventListener("mouseout", function() {
-                    this.parentElement.previousElementSibling.childNodes[0].style.color = "";
-                });
-            } else if (hasClass(e, "ignore")) {
-                e.addEventListener("mouseover", function() {
-                    this.parentElement.previousElementSibling.childNodes[0].style.color = "#ff9200";
-                });
-                e.addEventListener("mouseout", function() {
-                    this.parentElement.previousElementSibling.childNodes[0].style.color = "";
-                });
-            }
-            lineNumbersFunc(e);
-        });
     }());
 
     let oldSidebarScrollPosition = null;
diff --git a/src/librustdoc/html/static/js/settings.js b/src/librustdoc/html/static/js/settings.js
index 797b931afc64..1c5d33e21275 100644
--- a/src/librustdoc/html/static/js/settings.js
+++ b/src/librustdoc/html/static/js/settings.js
@@ -19,6 +19,13 @@
                 updateSystemTheme();
                 updateLightAndDark();
                 break;
+            case "line-numbers":
+                if (value === true) {
+                    window.rustdoc_add_line_numbers_to_examples();
+                } else {
+                    window.rustdoc_remove_line_numbers_from_examples();
+                }
+                break;
         }
     }
 
diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs
index 20b9eb1c27e9..49a31f5f1da1 100644
--- a/src/librustdoc/json/conversions.rs
+++ b/src/librustdoc/json/conversions.rs
@@ -19,6 +19,7 @@ use crate::clean::utils::print_const_expr;
 use crate::clean::{self, ItemId};
 use crate::formats::item_type::ItemType;
 use crate::json::JsonRenderer;
+use crate::passes::collect_intra_doc_links::UrlFragment;
 
 impl JsonRenderer<'_> {
     pub(super) fn convert_item(&self, item: clean::Item) -> Option<Item> {
@@ -29,8 +30,14 @@ impl JsonRenderer<'_> {
             .get(&item.item_id)
             .into_iter()
             .flatten()
-            .map(|clean::ItemLink { link, did, .. }| {
-                (link.clone(), from_item_id((*did).into(), self.tcx))
+            .map(|clean::ItemLink { link, page_id, fragment, .. }| {
+                let id = match fragment {
+                    Some(UrlFragment::Item(frag_id)) => *frag_id,
+                    // FIXME: Pass the `UserWritten` segment to JSON consumer.
+                    Some(UrlFragment::UserWritten(_)) | None => *page_id,
+                };
+
+                (link.clone(), from_item_id(id.into(), self.tcx))
             })
             .collect();
         let docs = item.attrs.collapsed_doc_value();
@@ -304,11 +311,19 @@ impl FromWithTcx<clean::Struct> for Struct {
     fn from_tcx(struct_: clean::Struct, tcx: TyCtxt<'_>) -> Self {
         let fields_stripped = struct_.has_stripped_entries();
         let clean::Struct { struct_type, generics, fields } = struct_;
+
+        let kind = match struct_type {
+            CtorKind::Fn => StructKind::Tuple(ids_keeping_stripped(fields, tcx)),
+            CtorKind::Const => {
+                assert!(fields.is_empty());
+                StructKind::Unit
+            }
+            CtorKind::Fictive => StructKind::Plain { fields: ids(fields, tcx), fields_stripped },
+        };
+
         Struct {
-            struct_type: from_ctor_kind(struct_type),
+            kind,
             generics: generics.into_tcx(tcx),
-            fields_stripped,
-            fields: ids(fields, tcx),
             impls: Vec::new(), // Added in JsonRenderer::item
         }
     }
@@ -327,14 +342,6 @@ impl FromWithTcx<clean::Union> for Union {
     }
 }
 
-pub(crate) fn from_ctor_kind(struct_type: CtorKind) -> StructType {
-    match struct_type {
-        CtorKind::Fictive => StructType::Plain,
-        CtorKind::Fn => StructType::Tuple,
-        CtorKind::Const => StructType::Unit,
-    }
-}
-
 pub(crate) fn from_fn_header(header: &rustc_hir::FnHeader) -> Header {
     Header {
         async_: header.is_async(),
@@ -486,7 +493,7 @@ impl FromWithTcx<clean::Type> for Type {
             },
             QPath(box clean::QPathData { assoc, self_type, trait_, .. }) => Type::QualifiedPath {
                 name: assoc.name.to_string(),
-                args: Box::new(assoc.args.clone().into_tcx(tcx)),
+                args: Box::new(assoc.args.into_tcx(tcx)),
                 self_type: Box::new(self_type.into_tcx(tcx)),
                 trait_: trait_.into_tcx(tcx),
             },
@@ -644,36 +651,28 @@ impl FromWithTcx<clean::Enum> for Enum {
     }
 }
 
-impl FromWithTcx<clean::VariantStruct> for Struct {
-    fn from_tcx(struct_: clean::VariantStruct, tcx: TyCtxt<'_>) -> Self {
-        let fields_stripped = struct_.has_stripped_entries();
-        let clean::VariantStruct { struct_type, fields } = struct_;
-        Struct {
-            struct_type: from_ctor_kind(struct_type),
-            generics: Generics { params: vec![], where_predicates: vec![] },
-            fields_stripped,
-            fields: ids(fields, tcx),
-            impls: Vec::new(),
-        }
-    }
-}
-
 impl FromWithTcx<clean::Variant> for Variant {
     fn from_tcx(variant: clean::Variant, tcx: TyCtxt<'_>) -> Self {
         use clean::Variant::*;
         match variant {
-            CLike => Variant::Plain,
-            Tuple(fields) => Variant::Tuple(
-                fields
-                    .into_iter()
-                    .filter_map(|f| match *f.kind {
-                        clean::StructFieldItem(ty) => Some(ty.into_tcx(tcx)),
-                        clean::StrippedItem(_) => None,
-                        _ => unreachable!(),
-                    })
-                    .collect(),
-            ),
-            Struct(s) => Variant::Struct(ids(s.fields, tcx)),
+            CLike(disr) => Variant::Plain(disr.map(|disr| disr.into_tcx(tcx))),
+            Tuple(fields) => Variant::Tuple(ids_keeping_stripped(fields, tcx)),
+            Struct(s) => Variant::Struct {
+                fields_stripped: s.has_stripped_entries(),
+                fields: ids(s.fields, tcx),
+            },
+        }
+    }
+}
+
+impl FromWithTcx<clean::Discriminant> for Discriminant {
+    fn from_tcx(disr: clean::Discriminant, tcx: TyCtxt<'_>) -> Self {
+        Discriminant {
+            // expr is only none if going throught the inlineing path, which gets
+            // `rustc_middle` types, not `rustc_hir`, but because JSON never inlines
+            // the expr is always some.
+            expr: disr.expr(tcx).unwrap(),
+            value: disr.value(tcx),
         }
     }
 }
@@ -784,3 +783,19 @@ fn ids(items: impl IntoIterator<Item = clean::Item>, tcx: TyCtxt<'_>) -> Vec<Id>
         .map(|i| from_item_id_with_name(i.item_id, tcx, i.name))
         .collect()
 }
+
+fn ids_keeping_stripped(
+    items: impl IntoIterator<Item = clean::Item>,
+    tcx: TyCtxt<'_>,
+) -> Vec<Option<Id>> {
+    items
+        .into_iter()
+        .map(|i| {
+            if !i.is_stripped() && !i.is_keyword() {
+                Some(from_item_id_with_name(i.item_id, tcx, i.name))
+            } else {
+                None
+            }
+        })
+        .collect()
+}
diff --git a/src/librustdoc/json/mod.rs b/src/librustdoc/json/mod.rs
index 6a1409c73942..5e8f5f6fe3eb 100644
--- a/src/librustdoc/json/mod.rs
+++ b/src/librustdoc/json/mod.rs
@@ -101,6 +101,7 @@ impl<'tcx> JsonRenderer<'tcx> {
     }
 
     fn get_trait_items(&mut self) -> Vec<(types::Id, types::Item)> {
+        debug!("Adding foreign trait items");
         Rc::clone(&self.cache)
             .traits
             .iter()
@@ -109,6 +110,7 @@ impl<'tcx> JsonRenderer<'tcx> {
                 if !id.is_local() {
                     let trait_item = &trait_item.trait_;
                     for item in &trait_item.items {
+                        trace!("Adding subitem to {id:?}: {:?}", item.item_id);
                         self.item(item.clone()).unwrap();
                     }
                     let item_id = from_item_id(id.into(), self.tcx);
@@ -184,7 +186,9 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
     /// the hashmap because certain items (traits and types) need to have their mappings for trait
     /// implementations filled out before they're inserted.
     fn item(&mut self, item: clean::Item) -> Result<(), Error> {
-        trace!("rendering {} {:?}", item.type_(), item.name);
+        let item_type = item.type_();
+        let item_name = item.name;
+        trace!("rendering {} {:?}", item_type, item_name);
 
         // Flatten items that recursively store other items. We include orphaned items from
         // stripped modules and etc that are otherwise reachable.
@@ -253,6 +257,7 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
             }
         }
 
+        trace!("done rendering {} {:?}", item_type, item_name);
         Ok(())
     }
 
@@ -263,14 +268,20 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
     fn after_krate(&mut self) -> Result<(), Error> {
         debug!("Done with crate");
 
+        debug!("Adding Primitve impls");
         for primitive in Rc::clone(&self.cache).primitive_locations.values() {
             self.get_impls(*primitive);
         }
 
         let e = ExternalCrate { crate_num: LOCAL_CRATE };
 
+        // FIXME(adotinthevoid): Remove this, as it's not consistant with not
+        // inlining foreign items.
+        let foreign_trait_items = self.get_trait_items();
         let mut index = (*self.index).clone().into_inner();
-        index.extend(self.get_trait_items());
+        index.extend(foreign_trait_items);
+
+        debug!("Constructing Output");
         // This needs to be the default HashMap for compatibility with the public interface for
         // rustdoc-json-types
         #[allow(rustc::default_hash_types)]
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 92380d124292..23e3de45fa51 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -9,14 +9,12 @@
 #![feature(control_flow_enum)]
 #![feature(drain_filter)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(test)]
 #![feature(never_type)]
 #![feature(once_cell)]
 #![feature(type_ascription)]
 #![feature(iter_intersperse)]
 #![feature(type_alias_impl_trait)]
-#![feature(generic_associated_types)]
 #![recursion_limit = "256"]
 #![warn(rustc::internal)]
 #![allow(clippy::collapsible_if, clippy::collapsible_else_if)]
@@ -461,7 +459,7 @@ fn opts() -> Vec<RustcOptGroup> {
                 "human|json|short",
             )
         }),
-        unstable("diagnostic-width", |o| {
+        stable("diagnostic-width", |o| {
             o.optopt(
                 "",
                 "diagnostic-width",
diff --git a/src/librustdoc/lint.rs b/src/librustdoc/lint.rs
index 240aec52cff0..e76c19a61c54 100644
--- a/src/librustdoc/lint.rs
+++ b/src/librustdoc/lint.rs
@@ -64,9 +64,13 @@ where
 }
 
 macro_rules! declare_rustdoc_lint {
-    ($(#[$attr:meta])* $name: ident, $level: ident, $descr: literal $(,)?) => {
+    (
+        $(#[$attr:meta])* $name: ident, $level: ident, $descr: literal $(,)?
+        $(@feature_gate = $gate:expr;)?
+    ) => {
         declare_tool_lint! {
             $(#[$attr])* pub rustdoc::$name, $level, $descr
+            $(, @feature_gate = $gate;)?
         }
     }
 }
@@ -123,7 +127,8 @@ declare_rustdoc_lint! {
     /// [rustdoc book]: ../../../rustdoc/lints.html#missing_doc_code_examples
     MISSING_DOC_CODE_EXAMPLES,
     Allow,
-    "detects publicly-exported items without code samples in their documentation"
+    "detects publicly-exported items without code samples in their documentation",
+    @feature_gate = rustc_span::symbol::sym::rustdoc_missing_doc_code_examples;
 }
 
 declare_rustdoc_lint! {
diff --git a/src/librustdoc/passes/check_doc_test_visibility.rs b/src/librustdoc/passes/check_doc_test_visibility.rs
index e86f9083394c..55d5f303d345 100644
--- a/src/librustdoc/passes/check_doc_test_visibility.rs
+++ b/src/librustdoc/passes/check_doc_test_visibility.rs
@@ -117,7 +117,7 @@ pub(crate) fn look_for_tests<'tcx>(cx: &DocContext<'tcx>, dox: &str, item: &Item
 
     find_testable_code(dox, &mut tests, ErrorCodes::No, false, None);
 
-    if tests.found_tests == 0 && cx.tcx.sess.is_nightly_build() {
+    if tests.found_tests == 0 && cx.tcx.features().rustdoc_missing_doc_code_examples {
         if should_have_doc_example(cx, item) {
             debug!("reporting error for {:?} (hir_id={:?})", item, hir_id);
             let sp = item.attr_span(cx.tcx);
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 7d7a63c53847..677c980f63cc 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -223,6 +223,9 @@ enum MalformedGenerics {
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub(crate) enum UrlFragment {
     Item(DefId),
+    /// A part of a page that isn't a rust item.
+    ///
+    /// Eg: `[Vector Examples](std::vec::Vec#examples)`
     UserWritten(String),
 }
 
@@ -477,7 +480,7 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
             // If there's no `::`, it's not an associated item.
             // So we can be sure that `rustc_resolve` was accurate when it said it wasn't resolved.
             .ok_or_else(|| {
-                debug!("found no `::`, assumming {} was correctly not in scope", item_name);
+                debug!("found no `::`, assuming {} was correctly not in scope", item_name);
                 UnresolvedPath {
                     item_id,
                     module_id,
@@ -750,7 +753,7 @@ fn resolve_associated_trait_item<'a>(
 ///
 /// This is just a wrapper around [`TyCtxt::impl_item_implementor_ids()`] and
 /// [`TyCtxt::associated_item()`] (with some helpful logging added).
-#[instrument(level = "debug", skip(tcx))]
+#[instrument(level = "debug", skip(tcx), ret)]
 fn trait_assoc_to_impl_assoc_item<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_id: DefId,
@@ -760,9 +763,7 @@ fn trait_assoc_to_impl_assoc_item<'tcx>(
     debug!(?trait_to_impl_assoc_map);
     let impl_assoc_id = *trait_to_impl_assoc_map.get(&trait_assoc_id)?;
     debug!(?impl_assoc_id);
-    let impl_assoc = tcx.associated_item(impl_assoc_id);
-    debug!(?impl_assoc);
-    Some(impl_assoc)
+    Some(tcx.associated_item(impl_assoc_id))
 }
 
 /// Given a type, return all trait impls in scope in `module` for that type.
@@ -1129,7 +1130,7 @@ impl LinkCollector<'_, '_> {
                 Some(ItemLink {
                     link: ori_link.link.clone(),
                     link_text: link_text.clone(),
-                    did: res.def_id(self.cx.tcx),
+                    page_id: res.def_id(self.cx.tcx),
                     fragment,
                 })
             }
@@ -1148,11 +1149,12 @@ impl LinkCollector<'_, '_> {
                     item,
                     &diag_info,
                 )?;
-                let id = clean::register_res(self.cx, rustc_hir::def::Res::Def(kind, id));
+
+                let page_id = clean::register_res(self.cx, rustc_hir::def::Res::Def(kind, id));
                 Some(ItemLink {
                     link: ori_link.link.clone(),
                     link_text: link_text.clone(),
-                    did: id,
+                    page_id,
                     fragment,
                 })
             }
@@ -1256,7 +1258,7 @@ impl LinkCollector<'_, '_> {
         &mut self,
         key: ResolutionInfo,
         diag: DiagnosticInfo<'_>,
-        // If errors are cached then they are only reported on first ocurrence
+        // If errors are cached then they are only reported on first occurrence
         // which we want in some cases but not in others.
         cache_errors: bool,
     ) -> Option<(Res, Option<UrlFragment>)> {
@@ -1807,8 +1809,8 @@ fn resolution_failure(
                                 }
                                 return;
                             }
-                            Trait | TyAlias | ForeignTy | OpaqueTy | TraitAlias | TyParam
-                            | Static(_) => "associated item",
+                            Trait | TyAlias | ForeignTy | OpaqueTy | ImplTraitPlaceholder
+                            | TraitAlias | TyParam | Static(_) => "associated item",
                             Impl | GlobalAsm => unreachable!("not a path"),
                         }
                     } else {
diff --git a/src/librustdoc/passes/html_tags.rs b/src/librustdoc/passes/html_tags.rs
index f3a3c853caca..885dadb32a8a 100644
--- a/src/librustdoc/passes/html_tags.rs
+++ b/src/librustdoc/passes/html_tags.rs
@@ -94,6 +94,34 @@ fn extract_path_backwards(text: &str, end_pos: usize) -> Option<usize> {
     if current_pos == end_pos { None } else { Some(current_pos) }
 }
 
+fn extract_path_forward(text: &str, start_pos: usize) -> Option<usize> {
+    use rustc_lexer::{is_id_continue, is_id_start};
+    let mut current_pos = start_pos;
+    loop {
+        if current_pos < text.len() && text[current_pos..].starts_with("::") {
+            current_pos += 2;
+        } else {
+            break;
+        }
+        let mut chars = text[current_pos..].chars();
+        if let Some(c) = chars.next() {
+            if is_id_start(c) {
+                current_pos += c.len_utf8();
+            } else {
+                break;
+            }
+        }
+        while let Some(c) = chars.next() {
+            if is_id_continue(c) {
+                current_pos += c.len_utf8();
+            } else {
+                break;
+            }
+        }
+    }
+    if current_pos == start_pos { None } else { Some(current_pos) }
+}
+
 fn is_valid_for_html_tag_name(c: char, is_empty: bool) -> bool {
     // https://spec.commonmark.org/0.30/#raw-html
     //
@@ -218,19 +246,68 @@ impl<'a, 'tcx> DocVisitor for InvalidHtmlTagsLinter<'a, 'tcx> {
                     // If a tag looks like `<this>`, it might actually be a generic.
                     // We don't try to detect stuff `<like, this>` because that's not valid HTML,
                     // and we don't try to detect stuff `<like this>` because that's not valid Rust.
-                    if let Some(Some(generics_start)) = (is_open_tag
-                        && dox[..range.end].ends_with('>'))
+                    let mut generics_end = range.end;
+                    if let Some(Some(mut generics_start)) = (is_open_tag
+                        && dox[..generics_end].ends_with('>'))
                     .then(|| extract_path_backwards(&dox, range.start))
                     {
+                        while generics_start != 0
+                            && generics_end < dox.len()
+                            && dox.as_bytes()[generics_start - 1] == b'<'
+                            && dox.as_bytes()[generics_end] == b'>'
+                        {
+                            generics_end += 1;
+                            generics_start -= 1;
+                            if let Some(new_start) = extract_path_backwards(&dox, generics_start) {
+                                generics_start = new_start;
+                            }
+                            if let Some(new_end) = extract_path_forward(&dox, generics_end) {
+                                generics_end = new_end;
+                            }
+                        }
+                        if let Some(new_end) = extract_path_forward(&dox, generics_end) {
+                            generics_end = new_end;
+                        }
                         let generics_sp = match super::source_span_for_markdown_range(
                             tcx,
                             &dox,
-                            &(generics_start..range.end),
+                            &(generics_start..generics_end),
                             &item.attrs,
                         ) {
                             Some(sp) => sp,
                             None => item.attr_span(tcx),
                         };
+                        // Sometimes, we only extract part of a path. For example, consider this:
+                        //
+                        //     <[u32] as IntoIter<u32>>::Item
+                        //                       ^^^^^ unclosed HTML tag `u32`
+                        //
+                        // We don't have any code for parsing fully-qualified trait paths.
+                        // In theory, we could add it, but doing it correctly would require
+                        // parsing the entire path grammar, which is problematic because of
+                        // overlap between the path grammar and Markdown.
+                        //
+                        // The example above shows that ambiguity. Is `[u32]` intended to be an
+                        // intra-doc link to the u32 primitive, or is it intended to be a slice?
+                        //
+                        // If the below conditional were removed, we would suggest this, which is
+                        // not what the user probably wants.
+                        //
+                        //     <[u32] as `IntoIter<u32>`>::Item
+                        //
+                        // We know that the user actually wants to wrap the whole thing in a code
+                        // block, but the only reason we know that is because `u32` does not, in
+                        // fact, implement IntoIter. If the example looks like this:
+                        //
+                        //     <[Vec<i32>] as IntoIter<i32>::Item
+                        //
+                        // The ideal fix would be significantly different.
+                        if (generics_start > 0 && dox.as_bytes()[generics_start - 1] == b'<')
+                            || (generics_end < dox.len() && dox.as_bytes()[generics_end] == b'>')
+                        {
+                            diag.emit();
+                            return;
+                        }
                         // multipart form is chosen here because ``Vec<i32>`` would be confusing.
                         diag.multipart_suggestion(
                             "try marking as source code",
@@ -278,7 +355,7 @@ impl<'a, 'tcx> DocVisitor for InvalidHtmlTagsLinter<'a, 'tcx> {
             for (event, range) in p {
                 match event {
                     Event::Start(Tag::CodeBlock(_)) => in_code_block = true,
-                    Event::Html(text) | Event::Text(text) if !in_code_block => {
+                    Event::Html(text) if !in_code_block => {
                         extract_tags(&mut tags, &text, range, &mut is_in_comment, &report_diag)
                     }
                     Event::End(Tag::CodeBlock(_)) => in_code_block = false,
diff --git a/src/librustdoc/passes/propagate_doc_cfg.rs b/src/librustdoc/passes/propagate_doc_cfg.rs
index 2b12d118bca0..de3a4b339059 100644
--- a/src/librustdoc/passes/propagate_doc_cfg.rs
+++ b/src/librustdoc/passes/propagate_doc_cfg.rs
@@ -3,7 +3,7 @@ use std::sync::Arc;
 
 use crate::clean::cfg::Cfg;
 use crate::clean::inline::{load_attrs, merge_attrs};
-use crate::clean::{Crate, Item};
+use crate::clean::{Crate, Item, ItemKind};
 use crate::core::DocContext;
 use crate::fold::DocFolder;
 use crate::passes::Pass;
@@ -26,30 +26,50 @@ struct CfgPropagator<'a, 'tcx> {
     cx: &'a mut DocContext<'tcx>,
 }
 
+impl<'a, 'tcx> CfgPropagator<'a, 'tcx> {
+    // Some items need to merge their attributes with their parents' otherwise a few of them
+    // (mostly `cfg` ones) will be missing.
+    fn merge_with_parent_attributes(&mut self, item: &mut Item) {
+        let check_parent = match &*item.kind {
+            // impl blocks can be in different modules with different cfg and we need to get them
+            // as well.
+            ItemKind::ImplItem(_) => false,
+            kind if kind.is_non_assoc() => true,
+            _ => return,
+        };
+
+        let Some(def_id) = item.item_id.as_def_id().and_then(|def_id| def_id.as_local())
+            else { return };
+
+        let hir = self.cx.tcx.hir();
+        let hir_id = hir.local_def_id_to_hir_id(def_id);
+
+        if check_parent {
+            let expected_parent = hir.get_parent_item(hir_id);
+            // If parents are different, it means that `item` is a reexport and we need
+            // to compute the actual `cfg` by iterating through its "real" parents.
+            if self.parent == Some(expected_parent.def_id) {
+                return;
+            }
+        }
+
+        let mut attrs = Vec::new();
+        for (parent_hir_id, _) in hir.parent_iter(hir_id) {
+            if let Some(def_id) = hir.opt_local_def_id(parent_hir_id) {
+                attrs.extend_from_slice(load_attrs(self.cx, def_id.to_def_id()));
+            }
+        }
+        let (_, cfg) = merge_attrs(self.cx, None, item.attrs.other_attrs.as_slice(), Some(&attrs));
+        item.cfg = cfg;
+    }
+}
+
 impl<'a, 'tcx> DocFolder for CfgPropagator<'a, 'tcx> {
     fn fold_item(&mut self, mut item: Item) -> Option<Item> {
         let old_parent_cfg = self.parent_cfg.clone();
 
-        if item.kind.is_non_assoc() &&
-            let Some(def_id) = item.item_id.as_def_id().and_then(|def_id| def_id.as_local()) {
-            let hir = self.cx.tcx.hir();
-            let hir_id = hir.local_def_id_to_hir_id(def_id);
-            let expected_parent = hir.get_parent_item(hir_id);
+        self.merge_with_parent_attributes(&mut item);
 
-            // If parents are different, it means that `item` is a reexport and we need to compute
-            // the actual `cfg` by iterating through its "real" parents.
-            if self.parent != Some(expected_parent) {
-                let mut attrs = Vec::new();
-                for (parent_hir_id, _) in hir.parent_iter(hir_id) {
-                    if let Some(def_id) = hir.opt_local_def_id(parent_hir_id) {
-                        attrs.extend_from_slice(load_attrs(self.cx, def_id.to_def_id()));
-                    }
-                }
-                let (_, cfg) =
-                    merge_attrs(self.cx, None, item.attrs.other_attrs.as_slice(), Some(&attrs));
-                item.cfg = cfg;
-            }
-        }
         let new_cfg = match (self.parent_cfg.take(), item.cfg.take()) {
             (None, None) => None,
             (Some(rc), None) | (None, Some(rc)) => Some(rc),
diff --git a/src/librustdoc/passes/stripper.rs b/src/librustdoc/passes/stripper.rs
index 83ed3752a824..a9d768f0149d 100644
--- a/src/librustdoc/passes/stripper.rs
+++ b/src/librustdoc/passes/stripper.rs
@@ -91,7 +91,7 @@ impl<'a> DocFolder for Stripper<'a> {
             clean::ExternCrateItem { .. } => {}
             clean::ImportItem(ref imp) => {
                 // Because json doesn't inline imports from private modules, we need to mark
-                // the imported item as retained so it's impls won't be stripped.i
+                // the imported item as retained so it's impls won't be stripped.
                 //
                 // FIXME: Is it necessary to check for json output here: See
                 // https://github.com/rust-lang/rust/pull/100325#discussion_r941495215
diff --git a/src/librustdoc/scrape_examples.rs b/src/librustdoc/scrape_examples.rs
index 0d9684025033..dfa6ba38b883 100644
--- a/src/librustdoc/scrape_examples.rs
+++ b/src/librustdoc/scrape_examples.rs
@@ -143,14 +143,14 @@ where
         // then we need to exit before calling typeck (which will panic). See
         // test/run-make/rustdoc-scrape-examples-invalid-expr for an example.
         let hir = tcx.hir();
-        if hir.maybe_body_owned_by(ex.hir_id.owner).is_none() {
+        if hir.maybe_body_owned_by(ex.hir_id.owner.def_id).is_none() {
             return;
         }
 
         // Get type of function if expression is a function call
         let (ty, call_span, ident_span) = match ex.kind {
             hir::ExprKind::Call(f, _) => {
-                let types = tcx.typeck(ex.hir_id.owner);
+                let types = tcx.typeck(ex.hir_id.owner.def_id);
 
                 if let Some(ty) = types.node_type_opt(f.hir_id) {
                     (ty, ex.span, f.span)
@@ -159,8 +159,8 @@ where
                     return;
                 }
             }
-            hir::ExprKind::MethodCall(path, _, call_span) => {
-                let types = tcx.typeck(ex.hir_id.owner);
+            hir::ExprKind::MethodCall(path, _, _, call_span) => {
+                let types = tcx.typeck(ex.hir_id.owner.def_id);
                 let Some(def_id) = types.type_dependent_def_id(ex.hir_id) else {
                     trace!("type_dependent_def_id({}) = None", ex.hir_id);
                     return;
@@ -183,9 +183,8 @@ where
 
         // If the enclosing item has a span coming from a proc macro, then we also don't want to include
         // the example.
-        let enclosing_item_span = tcx
-            .hir()
-            .span_with_body(tcx.hir().local_def_id_to_hir_id(tcx.hir().get_parent_item(ex.hir_id)));
+        let enclosing_item_span =
+            tcx.hir().span_with_body(tcx.hir().get_parent_item(ex.hir_id).into());
         if enclosing_item_span.from_expansion() {
             trace!("Rejecting expr ({call_span:?}) from macro item: {enclosing_item_span:?}");
             return;
diff --git a/src/librustdoc/theme.rs b/src/librustdoc/theme.rs
index 0118d7dd2072..e7a26cb346ee 100644
--- a/src/librustdoc/theme.rs
+++ b/src/librustdoc/theme.rs
@@ -1,271 +1,252 @@
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxHashMap;
+use std::collections::hash_map::Entry;
 use std::fs;
-use std::hash::{Hash, Hasher};
+use std::iter::Peekable;
 use std::path::Path;
+use std::str::Chars;
 
 use rustc_errors::Handler;
 
 #[cfg(test)]
 mod tests;
 
-#[derive(Debug, Clone, Eq)]
+#[derive(Debug)]
 pub(crate) struct CssPath {
-    pub(crate) name: String,
-    pub(crate) children: FxHashSet<CssPath>,
+    pub(crate) rules: FxHashMap<String, String>,
+    pub(crate) children: FxHashMap<String, CssPath>,
 }
 
-// This PartialEq implementation IS NOT COMMUTATIVE!!!
-//
-// The order is very important: the second object must have all first's rules.
-// However, the first is not required to have all of the second's rules.
-impl PartialEq for CssPath {
-    fn eq(&self, other: &CssPath) -> bool {
-        if self.name != other.name {
-            false
-        } else {
-            for child in &self.children {
-                if !other.children.iter().any(|c| child == c) {
-                    return false;
-                }
-            }
-            true
+/// When encountering a `"` or a `'`, returns the whole string, including the quote characters.
+fn get_string(iter: &mut Peekable<Chars<'_>>, string_start: char, buffer: &mut String) {
+    buffer.push(string_start);
+    while let Some(c) = iter.next() {
+        buffer.push(c);
+        if c == '\\' {
+            iter.next();
+        } else if c == string_start {
+            break;
         }
     }
 }
 
-impl Hash for CssPath {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        self.name.hash(state);
-        for x in &self.children {
-            x.hash(state);
+fn get_inside_paren(
+    iter: &mut Peekable<Chars<'_>>,
+    paren_start: char,
+    paren_end: char,
+    buffer: &mut String,
+) {
+    buffer.push(paren_start);
+    while let Some(c) = iter.next() {
+        handle_common_chars(c, buffer, iter);
+        if c == paren_end {
+            break;
         }
     }
 }
 
-impl CssPath {
-    fn new(name: String) -> CssPath {
-        CssPath { name, children: FxHashSet::default() }
-    }
-}
-
-/// All variants contain the position they occur.
-#[derive(Debug, Clone, Copy)]
-enum Events {
-    StartLineComment(usize),
-    StartComment(usize),
-    EndComment(usize),
-    InBlock(usize),
-    OutBlock(usize),
-}
-
-impl Events {
-    fn get_pos(&self) -> usize {
-        match *self {
-            Events::StartLineComment(p)
-            | Events::StartComment(p)
-            | Events::EndComment(p)
-            | Events::InBlock(p)
-            | Events::OutBlock(p) => p,
+/// Skips a `/*` comment.
+fn skip_comment(iter: &mut Peekable<Chars<'_>>) {
+    while let Some(c) = iter.next() {
+        if c == '*' && iter.next() == Some('/') {
+            break;
         }
     }
-
-    fn is_comment(&self) -> bool {
-        matches!(
-            self,
-            Events::StartLineComment(_) | Events::StartComment(_) | Events::EndComment(_)
-        )
-    }
 }
 
-fn previous_is_line_comment(events: &[Events]) -> bool {
-    matches!(events.last(), Some(&Events::StartLineComment(_)))
-}
-
-fn is_line_comment(pos: usize, v: &[u8], events: &[Events]) -> bool {
-    if let Some(&Events::StartComment(_)) = events.last() {
-        return false;
-    }
-    v[pos + 1] == b'/'
-}
-
-fn load_css_events(v: &[u8]) -> Vec<Events> {
-    let mut pos = 0;
-    let mut events = Vec::with_capacity(100);
-
-    while pos + 1 < v.len() {
-        match v[pos] {
-            b'/' if v[pos + 1] == b'*' => {
-                events.push(Events::StartComment(pos));
-                pos += 1;
-            }
-            b'/' if is_line_comment(pos, v, &events) => {
-                events.push(Events::StartLineComment(pos));
-                pos += 1;
-            }
-            b'\n' if previous_is_line_comment(&events) => {
-                events.push(Events::EndComment(pos));
-            }
-            b'*' if v[pos + 1] == b'/' => {
-                events.push(Events::EndComment(pos + 2));
-                pos += 1;
-            }
-            b'{' if !previous_is_line_comment(&events) => {
-                if let Some(&Events::StartComment(_)) = events.last() {
-                    pos += 1;
-                    continue;
-                }
-                events.push(Events::InBlock(pos + 1));
-            }
-            b'}' if !previous_is_line_comment(&events) => {
-                if let Some(&Events::StartComment(_)) = events.last() {
-                    pos += 1;
-                    continue;
-                }
-                events.push(Events::OutBlock(pos + 1));
-            }
-            _ => {}
+/// Skips a line comment (`//`).
+fn skip_line_comment(iter: &mut Peekable<Chars<'_>>) {
+    while let Some(c) = iter.next() {
+        if c == '\n' {
+            break;
         }
-        pos += 1;
     }
-    events
 }
 
-fn get_useful_next(events: &[Events], pos: &mut usize) -> Option<Events> {
-    while *pos < events.len() {
-        if !events[*pos].is_comment() {
-            return Some(events[*pos]);
+fn handle_common_chars(c: char, buffer: &mut String, iter: &mut Peekable<Chars<'_>>) {
+    match c {
+        '"' | '\'' => get_string(iter, c, buffer),
+        '/' if iter.peek() == Some(&'*') => skip_comment(iter),
+        '/' if iter.peek() == Some(&'/') => skip_line_comment(iter),
+        '(' => get_inside_paren(iter, c, ')', buffer),
+        '[' => get_inside_paren(iter, c, ']', buffer),
+        _ => buffer.push(c),
+    }
+}
+
+/// Returns a CSS property name. Ends when encountering a `:` character.
+///
+/// If the `:` character isn't found, returns `None`.
+///
+/// If a `{` character is encountered, returns an error.
+fn parse_property_name(iter: &mut Peekable<Chars<'_>>) -> Result<Option<String>, String> {
+    let mut content = String::new();
+
+    while let Some(c) = iter.next() {
+        match c {
+            ':' => return Ok(Some(content.trim().to_owned())),
+            '{' => return Err("Unexpected `{` in a `{}` block".to_owned()),
+            '}' => break,
+            _ => handle_common_chars(c, &mut content, iter),
         }
-        *pos += 1;
     }
-    None
+    Ok(None)
 }
 
-fn get_previous_positions(events: &[Events], mut pos: usize) -> Vec<usize> {
-    let mut ret = Vec::with_capacity(3);
+/// Try to get the value of a CSS property (the `#fff` in `color: #fff`). It'll stop when it
+/// encounters a `{` or a `;` character.
+///
+/// It returns the value string and a boolean set to `true` if the value is ended with a `}` because
+/// it means that the parent block is done and that we should notify the parent caller.
+fn parse_property_value(iter: &mut Peekable<Chars<'_>>) -> (String, bool) {
+    let mut value = String::new();
+    let mut out_block = false;
 
-    ret.push(events[pos].get_pos());
-    if pos > 0 {
-        pos -= 1;
+    while let Some(c) = iter.next() {
+        match c {
+            ';' => break,
+            '}' => {
+                out_block = true;
+                break;
+            }
+            _ => handle_common_chars(c, &mut value, iter),
+        }
     }
+    (value.trim().to_owned(), out_block)
+}
+
+/// This is used to parse inside a CSS `{}` block. If we encounter a new `{` inside it, we consider
+/// it as a new block and therefore recurse into `parse_rules`.
+fn parse_rules(
+    content: &str,
+    selector: String,
+    iter: &mut Peekable<Chars<'_>>,
+    paths: &mut FxHashMap<String, CssPath>,
+) -> Result<(), String> {
+    let mut rules = FxHashMap::default();
+    let mut children = FxHashMap::default();
+
     loop {
-        if pos < 1 || !events[pos].is_comment() {
-            let x = events[pos].get_pos();
-            if *ret.last().unwrap() != x {
-                ret.push(x);
-            } else {
-                ret.push(0);
-            }
+        // If the parent isn't a "normal" CSS selector, we only expect sub-selectors and not CSS
+        // properties.
+        if selector.starts_with('@') {
+            parse_selectors(content, iter, &mut children)?;
             break;
         }
-        ret.push(events[pos].get_pos());
-        pos -= 1;
-    }
-    if ret.len() & 1 != 0 && events[pos].is_comment() {
-        ret.push(0);
-    }
-    ret.iter().rev().cloned().collect()
-}
-
-fn build_rule(v: &[u8], positions: &[usize]) -> String {
-    minifier::css::minify(
-        &positions
-            .chunks(2)
-            .map(|x| ::std::str::from_utf8(&v[x[0]..x[1]]).unwrap_or(""))
-            .collect::<String>()
-            .trim()
-            .chars()
-            .filter_map(|c| match c {
-                '\n' | '\t' => Some(' '),
-                '/' | '{' | '}' => None,
-                c => Some(c),
-            })
-            .collect::<String>()
-            .split(' ')
-            .filter(|s| !s.is_empty())
-            .intersperse(" ")
-            .collect::<String>(),
-    )
-    .map(|css| css.to_string())
-    .unwrap_or_else(|_| String::new())
-}
-
-fn inner(v: &[u8], events: &[Events], pos: &mut usize) -> FxHashSet<CssPath> {
-    let mut paths = Vec::with_capacity(50);
-
-    while *pos < events.len() {
-        if let Some(Events::OutBlock(_)) = get_useful_next(events, pos) {
-            *pos += 1;
-            break;
-        }
-        if let Some(Events::InBlock(_)) = get_useful_next(events, pos) {
-            paths.push(CssPath::new(build_rule(v, &get_previous_positions(events, *pos))));
-            *pos += 1;
-        }
-        while let Some(Events::InBlock(_)) = get_useful_next(events, pos) {
-            if let Some(ref mut path) = paths.last_mut() {
-                for entry in inner(v, events, pos).iter() {
-                    path.children.insert(entry.clone());
+        let rule = match parse_property_name(iter)? {
+            Some(r) => {
+                if r.is_empty() {
+                    return Err(format!("Found empty rule in selector `{selector}`"));
                 }
+                r
+            }
+            None => break,
+        };
+        let (value, out_block) = parse_property_value(iter);
+        if value.is_empty() {
+            return Err(format!("Found empty value for rule `{rule}` in selector `{selector}`"));
+        }
+        match rules.entry(rule) {
+            Entry::Occupied(mut o) => {
+                *o.get_mut() = value;
+            }
+            Entry::Vacant(v) => {
+                v.insert(value);
             }
         }
-        if let Some(Events::OutBlock(_)) = get_useful_next(events, pos) {
-            *pos += 1;
+        if out_block {
+            break;
         }
     }
-    paths.iter().cloned().collect()
+
+    match paths.entry(selector) {
+        Entry::Occupied(mut o) => {
+            let v = o.get_mut();
+            for (key, value) in rules.into_iter() {
+                v.rules.insert(key, value);
+            }
+            for (sel, child) in children.into_iter() {
+                v.children.insert(sel, child);
+            }
+        }
+        Entry::Vacant(v) => {
+            v.insert(CssPath { rules, children });
+        }
+    }
+    Ok(())
 }
 
-pub(crate) fn load_css_paths(v: &[u8]) -> CssPath {
-    let events = load_css_events(v);
-    let mut pos = 0;
+pub(crate) fn parse_selectors(
+    content: &str,
+    iter: &mut Peekable<Chars<'_>>,
+    paths: &mut FxHashMap<String, CssPath>,
+) -> Result<(), String> {
+    let mut selector = String::new();
 
-    let mut parent = CssPath::new("parent".to_owned());
-    parent.children = inner(v, &events, &mut pos);
-    parent
+    while let Some(c) = iter.next() {
+        match c {
+            '{' => {
+                let s = minifier::css::minify(selector.trim()).map(|s| s.to_string())?;
+                parse_rules(content, s, iter, paths)?;
+                selector.clear();
+            }
+            '}' => break,
+            ';' => selector.clear(), // We don't handle inline selectors like `@import`.
+            _ => handle_common_chars(c, &mut selector, iter),
+        }
+    }
+    Ok(())
 }
 
-pub(crate) fn get_differences(against: &CssPath, other: &CssPath, v: &mut Vec<String>) {
-    if against.name == other.name {
-        for child in &against.children {
-            let mut found = false;
-            let mut found_working = false;
-            let mut tmp = Vec::new();
+/// The entry point to parse the CSS rules. Every time we encounter a `{`, we then parse the rules
+/// inside it.
+pub(crate) fn load_css_paths(content: &str) -> Result<FxHashMap<String, CssPath>, String> {
+    let mut iter = content.chars().peekable();
+    let mut paths = FxHashMap::default();
 
-            for other_child in &other.children {
-                if child.name == other_child.name {
-                    if child != other_child {
-                        get_differences(child, other_child, &mut tmp);
-                    } else {
-                        found_working = true;
+    parse_selectors(content, &mut iter, &mut paths)?;
+    Ok(paths)
+}
+
+pub(crate) fn get_differences(
+    origin: &FxHashMap<String, CssPath>,
+    against: &FxHashMap<String, CssPath>,
+    v: &mut Vec<String>,
+) {
+    for (selector, entry) in origin.iter() {
+        match against.get(selector) {
+            Some(a) => {
+                get_differences(&entry.children, &a.children, v);
+                if selector == ":root" {
+                    // We need to check that all variables have been set.
+                    for rule in entry.rules.keys() {
+                        if !a.rules.contains_key(rule) {
+                            v.push(format!("  Missing CSS variable `{rule}` in `:root`"));
+                        }
                     }
-                    found = true;
-                    break;
                 }
             }
-            if !found {
-                v.push(format!("  Missing \"{}\" rule", child.name));
-            } else if !found_working {
-                v.extend(tmp.iter().cloned());
-            }
+            None => v.push(format!("  Missing rule `{selector}`")),
         }
     }
 }
 
 pub(crate) fn test_theme_against<P: AsRef<Path>>(
     f: &P,
-    against: &CssPath,
+    origin: &FxHashMap<String, CssPath>,
     diag: &Handler,
 ) -> (bool, Vec<String>) {
-    let data = match fs::read(f) {
+    let against = match fs::read_to_string(f)
+        .map_err(|e| e.to_string())
+        .and_then(|data| load_css_paths(&data))
+    {
         Ok(c) => c,
         Err(e) => {
-            diag.struct_err(&e.to_string()).emit();
+            diag.struct_err(&e).emit();
             return (false, vec![]);
         }
     };
 
-    let paths = load_css_paths(&data);
     let mut ret = vec![];
-    get_differences(against, &paths, &mut ret);
+    get_differences(origin, &against, &mut ret);
     (true, ret)
 }
diff --git a/src/librustdoc/theme/tests.rs b/src/librustdoc/theme/tests.rs
index ae8f43c6d55b..08a174d27d35 100644
--- a/src/librustdoc/theme/tests.rs
+++ b/src/librustdoc/theme/tests.rs
@@ -44,11 +44,7 @@ rule j end {}
 "#;
 
     let mut ret = Vec::new();
-    get_differences(
-        &load_css_paths(against.as_bytes()),
-        &load_css_paths(text.as_bytes()),
-        &mut ret,
-    );
+    get_differences(&load_css_paths(against).unwrap(), &load_css_paths(text).unwrap(), &mut ret);
     assert!(ret.is_empty());
 }
 
@@ -61,46 +57,45 @@ a
 c // sdf
 d {}
 "#;
-    let paths = load_css_paths(text.as_bytes());
-    assert!(paths.children.contains(&CssPath::new("a b c d".to_owned())));
+    let paths = load_css_paths(text).unwrap();
+    assert!(paths.contains_key(&"a b c d".to_owned()));
 }
 
 #[test]
 fn test_comparison() {
-    let x = r#"
-a {
-    b {
-        c {}
-    }
+    let origin = r#"
+@a {
+    b {}
+    c {}
 }
 "#;
 
-    let y = r#"
-a {
+    let against = r#"
+@a {
     b {}
 }
 "#;
 
-    let against = load_css_paths(y.as_bytes());
-    let other = load_css_paths(x.as_bytes());
+    let origin = load_css_paths(origin).unwrap();
+    let against = load_css_paths(against).unwrap();
 
     let mut ret = Vec::new();
-    get_differences(&against, &other, &mut ret);
+    get_differences(&against, &origin, &mut ret);
     assert!(ret.is_empty());
-    get_differences(&other, &against, &mut ret);
-    assert_eq!(ret, vec!["  Missing \"c\" rule".to_owned()]);
+    get_differences(&origin, &against, &mut ret);
+    assert_eq!(ret, vec!["  Missing rule `c`".to_owned()]);
 }
 
 #[test]
 fn check_empty_css() {
-    let events = load_css_events(&[]);
-    assert_eq!(events.len(), 0);
+    let paths = load_css_paths("").unwrap();
+    assert_eq!(paths.len(), 0);
 }
 
 #[test]
 fn check_invalid_css() {
-    let events = load_css_events(b"*");
-    assert_eq!(events.len(), 0);
+    let paths = load_css_paths("*").unwrap();
+    assert_eq!(paths.len(), 0);
 }
 
 #[test]
@@ -108,10 +103,85 @@ fn test_with_minification() {
     let text = include_str!("../html/static/css/themes/dark.css");
     let minified = minifier::css::minify(&text).expect("CSS minification failed").to_string();
 
-    let against = load_css_paths(text.as_bytes());
-    let other = load_css_paths(minified.as_bytes());
+    let against = load_css_paths(text).unwrap();
+    let other = load_css_paths(&minified).unwrap();
 
     let mut ret = Vec::new();
     get_differences(&against, &other, &mut ret);
     assert!(ret.is_empty());
 }
+
+#[test]
+fn test_media() {
+    let text = r#"
+@media (min-width: 701px) {
+    a:hover {
+        color: #fff;
+    }
+
+    b {
+        x: y;
+    }
+}
+
+@media (max-width: 1001px) {
+    b {
+        x: y;
+    }
+}
+"#;
+
+    let paths = load_css_paths(text).unwrap();
+    let p = paths.get("@media (min-width:701px)");
+    assert!(p.is_some());
+    let p = p.unwrap();
+    assert!(p.children.get("a:hover").is_some());
+    assert!(p.children.get("b").is_some());
+
+    let p = paths.get("@media (max-width:1001px)");
+    assert!(p.is_some());
+    let p = p.unwrap();
+    assert!(p.children.get("b").is_some());
+}
+
+#[test]
+fn test_css_variables() {
+    let x = r#"
+:root {
+    --a: #fff;
+}
+"#;
+
+    let y = r#"
+:root {
+    --a: #fff;
+    --b: #fff;
+}
+"#;
+
+    let against = load_css_paths(x).unwrap();
+    let other = load_css_paths(y).unwrap();
+
+    let mut ret = Vec::new();
+    get_differences(&against, &other, &mut ret);
+    assert!(ret.is_empty());
+    get_differences(&other, &against, &mut ret);
+    assert_eq!(ret, vec!["  Missing CSS variable `--b` in `:root`".to_owned()]);
+}
+
+#[test]
+fn test_weird_rule_value() {
+    let x = r#"
+a[text=("a")] {
+    b: url({;}.png);
+    c: #fff
+}
+"#;
+
+    let paths = load_css_paths(&x).unwrap();
+    let p = paths.get("a[text=(\"a\")]");
+    assert!(p.is_some());
+    let p = p.unwrap();
+    assert_eq!(p.rules.get("b"), Some(&"url({;}.png)".to_owned()));
+    assert_eq!(p.rules.get("c"), Some(&"#fff".to_owned()));
+}
diff --git a/src/librustdoc/visit.rs b/src/librustdoc/visit.rs
index 0bb41977c97c..c40274394f34 100644
--- a/src/librustdoc/visit.rs
+++ b/src/librustdoc/visit.rs
@@ -20,7 +20,7 @@ pub(crate) trait DocVisitor: Sized {
             VariantItem(i) => match i {
                 Variant::Struct(j) => j.fields.iter().for_each(|x| self.visit_item(x)),
                 Variant::Tuple(fields) => fields.iter().for_each(|x| self.visit_item(x)),
-                Variant::CLike => {}
+                Variant::CLike(_) => {}
             },
             ExternCrateItem { src: _ }
             | ImportItem(_)
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index ca7a20bf3688..e6cef4a326ac 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -164,8 +164,20 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         self.inside_public_path &= self.cx.tcx.visibility(def_id).is_public();
         for &i in m.item_ids {
             let item = self.cx.tcx.hir().item(i);
+            if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
+                continue;
+            }
             self.visit_item(item, None, &mut om);
         }
+        for &i in m.item_ids {
+            let item = self.cx.tcx.hir().item(i);
+            // To match the way import precedence works, visit glob imports last.
+            // Later passes in rustdoc will de-duplicate by name and kind, so if glob-
+            // imported items appear last, then they'll be the ones that get discarded.
+            if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
+                self.visit_item(item, None, &mut om);
+            }
+        }
         self.inside_public_path = orig_inside_public_path;
         om
     }
@@ -218,7 +230,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                     } else {
                         // All items need to be handled here in case someone wishes to link
                         // to them with intra-doc links
-                        self.cx.cache.access_levels.map.insert(did, AccessLevel::Public);
+                        self.cx.cache.access_levels.set_access_level(did, AccessLevel::Public);
                     }
                 }
             }
diff --git a/src/librustdoc/visit_lib.rs b/src/librustdoc/visit_lib.rs
index f01ec38665c0..8221e0998d79 100644
--- a/src/librustdoc/visit_lib.rs
+++ b/src/librustdoc/visit_lib.rs
@@ -38,10 +38,10 @@ impl<'a, 'tcx> LibEmbargoVisitor<'a, 'tcx> {
     fn update(&mut self, did: DefId, level: Option<AccessLevel>) -> Option<AccessLevel> {
         let is_hidden = self.tcx.is_doc_hidden(did);
 
-        let old_level = self.access_levels.map.get(&did).cloned();
+        let old_level = self.access_levels.get_access_level(did);
         // Accessibility levels can only grow
         if level > old_level && !is_hidden {
-            self.access_levels.map.insert(did, level.unwrap());
+            self.access_levels.set_access_level(did, level.unwrap());
             level
         } else {
             old_level
diff --git a/src/llvm-project b/src/llvm-project
index e3be3f64ecac..670e5f673acb 160000
--- a/src/llvm-project
+++ b/src/llvm-project
@@ -1 +1 @@
-Subproject commit e3be3f64ecac101d14ceda759ba078ad0aaf3747
+Subproject commit 670e5f673acb736acbfce65e0ffe2c8cd115b93f
diff --git a/src/rustdoc-json-types/lib.rs b/src/rustdoc-json-types/lib.rs
index 7dcad66b1f99..fb183042670e 100644
--- a/src/rustdoc-json-types/lib.rs
+++ b/src/rustdoc-json-types/lib.rs
@@ -9,7 +9,7 @@ use std::path::PathBuf;
 use serde::{Deserialize, Serialize};
 
 /// rustdoc format-version.
-pub const FORMAT_VERSION: u32 = 18;
+pub const FORMAT_VERSION: u32 = 21;
 
 /// A `Crate` is the root of the emitted JSON blob. It contains all type/documentation information
 /// about the language items in the local crate, as well as info about external items to allow
@@ -289,13 +289,39 @@ pub struct Union {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub struct Struct {
-    pub struct_type: StructType,
+    pub kind: StructKind,
     pub generics: Generics,
-    pub fields_stripped: bool,
-    pub fields: Vec<Id>,
     pub impls: Vec<Id>,
 }
 
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum StructKind {
+    /// A struct with no fields and no parentheses.
+    ///
+    /// ```rust
+    /// pub struct Unit;
+    /// ```
+    Unit,
+    /// A struct with unnamed fields.
+    ///
+    /// ```rust
+    /// pub struct TupleStruct(i32);
+    /// pub struct EmptyTupleStruct();
+    /// ```
+    ///
+    /// All [`Id`]'s will point to [`ItemEnum::StructField`]. Private and
+    /// `#[doc(hidden)]` fields will be given as `None`
+    Tuple(Vec<Option<Id>>),
+    /// A struct with nammed fields.
+    ///
+    /// ```rust
+    /// pub struct PlainStruct { x: i32 }
+    /// pub struct EmptyPlainStruct {}
+    /// ```
+    Plain { fields: Vec<Id>, fields_stripped: bool },
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub struct Enum {
     pub generics: Generics,
@@ -308,17 +334,53 @@ pub struct Enum {
 #[serde(rename_all = "snake_case")]
 #[serde(tag = "variant_kind", content = "variant_inner")]
 pub enum Variant {
-    Plain,
-    Tuple(Vec<Type>),
-    Struct(Vec<Id>),
+    /// A variant with no parentheses, and possible discriminant.
+    ///
+    /// ```rust
+    /// enum Demo {
+    ///     PlainVariant,
+    ///     PlainWithDiscriminant = 1,
+    /// }
+    /// ```
+    Plain(Option<Discriminant>),
+    /// A variant with unnamed fields.
+    ///
+    /// Unlike most of json, `#[doc(hidden)]` fields will be given as `None`
+    /// instead of being ommited, because order matters.
+    ///
+    /// ```rust
+    /// enum Demo {
+    ///     TupleVariant(i32),
+    ///     EmptyTupleVariant(),
+    /// }
+    /// ```
+    Tuple(Vec<Option<Id>>),
+    /// A variant with named fields.
+    ///
+    /// ```rust
+    /// enum Demo {
+    ///     StructVariant { x: i32 },
+    ///     EmptyStructVariant {},
+    /// }
+    /// ```
+    Struct { fields: Vec<Id>, fields_stripped: bool },
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
-#[serde(rename_all = "snake_case")]
-pub enum StructType {
-    Plain,
-    Tuple,
-    Unit,
+pub struct Discriminant {
+    /// The expression that produced the discriminant.
+    ///
+    /// Unlike `value`, this preserves the original formatting (eg suffixes,
+    /// hexadecimal, and underscores), making it unsuitable to be machine
+    /// interpreted.
+    ///
+    /// In some cases, when the value is to complex, this may be `"{ _ }"`.
+    /// When this occurs is unstable, and may change without notice.
+    pub expr: String,
+    /// The numerical value of the discriminant. Stored as a string due to
+    /// JSON's poor support for large integers, and the fact that it would need
+    /// to store from [`i128::MIN`] to [`u128::MAX`].
+    pub value: String,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
@@ -480,12 +542,12 @@ pub enum Term {
 #[serde(rename_all = "snake_case")]
 #[serde(tag = "kind", content = "inner")]
 pub enum Type {
-    /// Structs, enums, and traits
+    /// Structs, enums, and unions
     ResolvedPath(Path),
     DynTrait(DynTrait),
     /// Parameterized types
     Generic(String),
-    /// Fixed-size numeric types (plus int/usize/float), char, arrays, slices, and tuples
+    /// Built in numberic (i*, u*, f*) types, bool, and char
     Primitive(String),
     /// `extern "ABI" fn`
     FunctionPointer(Box<FunctionPointer>),
diff --git a/src/rustdoc-json-types/tests.rs b/src/rustdoc-json-types/tests.rs
index e7f6447ed875..399ff54b2949 100644
--- a/src/rustdoc-json-types/tests.rs
+++ b/src/rustdoc-json-types/tests.rs
@@ -3,10 +3,8 @@ use super::*;
 #[test]
 fn test_struct_info_roundtrip() {
     let s = ItemEnum::Struct(Struct {
-        struct_type: StructType::Plain,
         generics: Generics { params: vec![], where_predicates: vec![] },
-        fields_stripped: false,
-        fields: vec![],
+        kind: StructKind::Plain { fields: vec![], fields_stripped: false },
         impls: vec![],
     });
 
diff --git a/src/stage0.json b/src/stage0.json
index c4891a9858bf..72308d50c8eb 100644
--- a/src/stage0.json
+++ b/src/stage0.json
@@ -17,349 +17,349 @@
     "tool is executed."
   ],
   "compiler": {
-    "date": "2022-08-19",
+    "date": "2022-09-20",
     "version": "beta"
   },
   "rustfmt": {
-    "date": "2022-08-20",
+    "date": "2022-09-20",
     "version": "nightly"
   },
   "checksums_sha256": {
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+    "dist/2022-09-20/rustfmt-nightly-mipsel-unknown-linux-gnu.tar.xz": "bd71382043ea4e934640a60660169d8785af453415d88945066bd6b8a42b0099",
+    "dist/2022-09-20/rustfmt-nightly-powerpc-unknown-linux-gnu.tar.gz": "86feeca2cb543476419583bc1b10dbf8d91afd25ac77a9f04f789aff4f34e3e6",
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+    "dist/2022-09-20/rustfmt-nightly-powerpc64-unknown-linux-gnu.tar.gz": "ed7e14c85bb1dd2900991775e812c56a76891a70dbea013bff06f73e7d1beaba",
+    "dist/2022-09-20/rustfmt-nightly-powerpc64-unknown-linux-gnu.tar.xz": "09710d4622fd7a9695d3907be6433c69f2ff590415fab776a05ba74ea5be63a9",
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+    "dist/2022-09-20/rustfmt-nightly-powerpc64le-unknown-linux-gnu.tar.xz": "1f4465079a5493ec23f433cae4af3f633885b38f6ba7693387ccd355010b955e",
+    "dist/2022-09-20/rustfmt-nightly-riscv64gc-unknown-linux-gnu.tar.gz": "a9a3bdba43897b0ab44c54537ce80fc969c378480348af715e293403b55b83be",
+    "dist/2022-09-20/rustfmt-nightly-riscv64gc-unknown-linux-gnu.tar.xz": "2d58863182dac199cde47e12d3d92a64b5d068afc7e97e1047ae8b369fbe6df9",
+    "dist/2022-09-20/rustfmt-nightly-s390x-unknown-linux-gnu.tar.gz": "002667d802f1ff1224318c2090caaa3eefd18dabd1bcd40ad957b0c09acd047a",
+    "dist/2022-09-20/rustfmt-nightly-s390x-unknown-linux-gnu.tar.xz": "a34aa6451cf5faf985967ec5df78a41b21ae317bba7f8836e09f87571a7f9c16",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-apple-darwin.tar.gz": "8950773a8433fcc68f16c1e07210c3cf07c9e9240df92b0a90c67ca285d932f8",
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+    "dist/2022-09-20/rustfmt-nightly-x86_64-pc-windows-gnu.tar.gz": "cdbef502285d5eec5788299354f391a2263858d630466cd1cc6d48748aefb1af",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-pc-windows-gnu.tar.xz": "d5e04d0abda5e8ec429794a58f6404a6b95cc66cb218a52299c3bfaf1ec35485",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-pc-windows-msvc.tar.gz": "d1ec51e70918e4f50463839eb86528582424d69eecc6af5cd07987621acc713e",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-pc-windows-msvc.tar.xz": "64a108e60c1ff0e1c004d63e13a8180e5b266382e8434aa94eaff3c654158e51",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-freebsd.tar.gz": "d439ce2780177b3123de9a4c6727ea19831a215d19363d12b0bcc3bc19fc5074",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-freebsd.tar.xz": "851adf8da102068b4195a78ba587e168b7c4471b5a2e66451385a503362d091d",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-illumos.tar.gz": "7bad988696f60f49c0ab1929f8cfe843effaa455ab1d20b002dadd1e10bc4ded",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-illumos.tar.xz": "8bee32774f9af0b6f382640592b65d4187401a59bd3bea4a139e2dc43471bc0c",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-linux-gnu.tar.gz": "16a3ff01a6bc471da2195c7e8d0a6623b911d956db388b66e39096a7c81ae1d4",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-linux-gnu.tar.xz": "721115ea0ec7902f74d203eaadc71c79c4489caf9a23b0a81c513fddce5fb9b2",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-linux-musl.tar.gz": "9042aba5f18ef575cff2e106c34b707d8fe013f4140e4a066ce80f2103563809",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-linux-musl.tar.xz": "9106ee07a9f173ae845ae2b5ce30798e15deffd46149430ec5aacceaed7848b8",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-netbsd.tar.gz": "9acb78526c40efdfa0087373d802b30b75238e4c46e0bb18262e16416be49b4b",
+    "dist/2022-09-20/rustfmt-nightly-x86_64-unknown-netbsd.tar.xz": "c7a73c5b9034417998800dabb08ba71e12713a299457381a4437ea454cead1bd"
   }
 }
diff --git a/src/test/auxiliary/rust_test_helpers.c b/src/test/auxiliary/rust_test_helpers.c
index 92b7dd4b7c51..977ea487a980 100644
--- a/src/test/auxiliary/rust_test_helpers.c
+++ b/src/test/auxiliary/rust_test_helpers.c
@@ -1,6 +1,7 @@
 // Helper functions used only in tests
 
 #include <stdint.h>
+#include <stdlib.h>
 #include <assert.h>
 #include <stdarg.h>
 
@@ -415,3 +416,14 @@ rust_dbg_unpack_option_u64u64(struct U8TaggedEnumOptionU64U64 o, uint64_t *a, ui
         return 0;
     }
 }
+
+uint16_t issue_97463_leak_uninit_data(uint32_t a, uint32_t b, uint32_t c) {
+    struct bloc { uint16_t a; uint16_t b; uint16_t c; };
+    struct bloc *data = malloc(sizeof(struct bloc));
+
+    data->a = a & 0xFFFF;
+    data->b = b & 0xFFFF;
+    data->c = c & 0xFFFF;
+
+    return data->b; /* leak data */
+}
diff --git a/src/test/codegen-units/item-collection/generic-impl.rs b/src/test/codegen-units/item-collection/generic-impl.rs
index dd5367ef0380..4260230c2c67 100644
--- a/src/test/codegen-units/item-collection/generic-impl.rs
+++ b/src/test/codegen-units/item-collection/generic-impl.rs
@@ -30,11 +30,11 @@ pub struct LifeTimeOnly<'a> {
 
 impl<'a> LifeTimeOnly<'a> {
 
-    //~ MONO_ITEM fn LifeTimeOnly::foo
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::foo
     pub fn foo(&self) {}
-    //~ MONO_ITEM fn LifeTimeOnly::bar
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::bar
     pub fn bar(&'a self) {}
-    //~ MONO_ITEM fn LifeTimeOnly::baz
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::baz
     pub fn baz<'b>(&'b self) {}
 
     pub fn non_instantiated<T>(&self) {}
diff --git a/src/test/codegen/abi-repr-ext.rs b/src/test/codegen/abi-repr-ext.rs
index 2b34eaf94172..23ade3c7216d 100644
--- a/src/test/codegen/abi-repr-ext.rs
+++ b/src/test/codegen/abi-repr-ext.rs
@@ -1,6 +1,32 @@
 // compile-flags: -O
 
-#![crate_type="lib"]
+// revisions:x86_64 i686 aarch64-apple aarch64-windows aarch64-linux arm riscv
+
+//[x86_64] compile-flags: --target x86_64-unknown-uefi
+//[x86_64] needs-llvm-components: x86
+//[i686] compile-flags: --target i686-unknown-linux-musl
+//[i686] needs-llvm-components: x86
+//[aarch64-windows] compile-flags: --target aarch64-pc-windows-msvc
+//[aarch64-windows] needs-llvm-components: aarch64
+//[aarch64-linux] compile-flags: --target aarch64-unknown-linux-gnu
+//[aarch64-linux] needs-llvm-components: aarch64
+//[aarch64-apple] compile-flags: --target aarch64-apple-darwin
+//[aarch64-apple] needs-llvm-components: aarch64
+//[arm] compile-flags: --target armv7r-none-eabi
+//[arm] needs-llvm-components: arm
+//[riscv] compile-flags: --target riscv64gc-unknown-none-elf
+//[riscv] needs-llvm-components: riscv
+
+// See bottom of file for a corresponding C source file that is meant to yield
+// equivalent declarations.
+#![feature(no_core, lang_items)]
+#![crate_type = "lib"]
+#![no_std]
+#![no_core]
+
+#[lang="sized"] trait Sized { }
+#[lang="freeze"] trait Freeze { }
+#[lang="copy"] trait Copy { }
 
 #[repr(i8)]
 pub enum Type {
@@ -8,7 +34,23 @@ pub enum Type {
     Type2 = 1
 }
 
-// CHECK: define{{( dso_local)?}} noundef signext i8 @test()
+// To accommodate rust#97800, one might consider writing the below as:
+//
+// `define{{( dso_local)?}} noundef{{( signext)?}} i8 @test()`
+//
+// but based on rust#80556, it seems important to actually check for the
+// presence of the `signext` for those targets where we expect it.
+
+// CHECK: define{{( dso_local)?}} noundef
+// x86_64-SAME:                 signext
+// aarch64-apple-SAME:          signext
+// aarch64-windows-NOT: signext
+// aarch64-linux-NOT:   signext
+// arm-SAME:                    signext
+// riscv-SAME:                  signext
+// CHECK-SAME: i8 @test()
+
+
 #[no_mangle]
 pub extern "C" fn test() -> Type {
     Type::Type1
diff --git a/src/test/codegen/avr/avr-func-addrspace.rs b/src/test/codegen/avr/avr-func-addrspace.rs
index 530164edd468..a038dfe76f70 100644
--- a/src/test/codegen/avr/avr-func-addrspace.rs
+++ b/src/test/codegen/avr/avr-func-addrspace.rs
@@ -77,7 +77,7 @@ fn update_bar_value() {
     }
 }
 
-// CHECK: define void @test(){{.+}}addrspace(1)
+// CHECK: define dso_local void @test(){{.+}}addrspace(1)
 #[no_mangle]
 pub extern "C" fn test() {
     let mut buf = 7;
diff --git a/src/test/codegen/generator-debug-msvc.rs b/src/test/codegen/generator-debug-msvc.rs
index b712068bf27f..9d70ccdef032 100644
--- a/src/test/codegen/generator-debug-msvc.rs
+++ b/src/test/codegen/generator-debug-msvc.rs
@@ -27,11 +27,11 @@ fn generator_test() -> impl Generator<Yield = i32, Return = ()> {
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: )
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant1", scope: [[GEN]],
-// CHECK-SAME: file: [[FILE]], line: 14,
+// CHECK-SAME: file: [[FILE]], line: 18,
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: )
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant2", scope: [[GEN]],
-// CHECK-SAME: file: [[FILE]], line: 14,
+// CHECK-SAME: file: [[FILE]], line: 18,
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: )
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant3", scope: [[GEN]],
diff --git a/src/test/codegen/generator-debug.rs b/src/test/codegen/generator-debug.rs
index 9c9f5518b664..3ec860f2cbc0 100644
--- a/src/test/codegen/generator-debug.rs
+++ b/src/test/codegen/generator-debug.rs
@@ -33,11 +33,11 @@ fn generator_test() -> impl Generator<Yield = i32, Return = ()> {
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: )
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "1", scope: [[VARIANT]],
-// CHECK-SAME: file: [[FILE]], line: 14,
+// CHECK-SAME: file: [[FILE]], line: 18,
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: )
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "2", scope: [[VARIANT]],
-// CHECK-SAME: file: [[FILE]], line: 14,
+// CHECK-SAME: file: [[FILE]], line: 18,
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: )
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "3", scope: [[VARIANT]],
diff --git a/src/test/codegen/issue-34634.rs b/src/test/codegen/issue-34634.rs
index 6c18adbcb3c9..f53fa240cd1a 100644
--- a/src/test/codegen/issue-34634.rs
+++ b/src/test/codegen/issue-34634.rs
@@ -1,5 +1,5 @@
 // Test that `wrapping_div` only checks divisor once.
-// This test checks that there is only a single compare agains -1 and -1 is not present as a
+// This test checks that there is only a single compare against -1 and -1 is not present as a
 // switch case (the second check present until rustc 1.12).
 // This test also verifies that a single panic call is generated (for the division by zero case).
 
diff --git a/src/test/codegen/issue-98294-get-mut-copy-from-slice-opt.rs b/src/test/codegen/issue-98294-get-mut-copy-from-slice-opt.rs
new file mode 100644
index 000000000000..7da29cd79529
--- /dev/null
+++ b/src/test/codegen/issue-98294-get-mut-copy-from-slice-opt.rs
@@ -0,0 +1,19 @@
+// min-llvm-version: 15.0.0
+// ignore-debug: The debug assertions get in the way
+// compile-flags: -O
+
+#![crate_type = "lib"]
+
+// There should be no calls to panic / len_mismatch_fail.
+
+#[no_mangle]
+pub fn test(a: &mut [u8], offset: usize, bytes: &[u8]) {
+    // CHECK-LABEL: @test(
+    // CHECK-NOT: call
+    // CHECK: call void @llvm.memcpy
+    // CHECK-NOT: call
+    // CHECK: }
+    if let Some(dst) = a.get_mut(offset..offset + bytes.len()) {
+        dst.copy_from_slice(bytes);
+    }
+}
diff --git a/src/test/codegen/pic-relocation-model.rs b/src/test/codegen/pic-relocation-model.rs
index bcfe2f9af50b..602a08067bae 100644
--- a/src/test/codegen/pic-relocation-model.rs
+++ b/src/test/codegen/pic-relocation-model.rs
@@ -10,7 +10,10 @@ pub fn call_foreign_fn() -> u8 {
     }
 }
 
-// CHECK: declare zeroext i8 @foreign_fn()
+// (Allow but do not require `zeroext` here, because it is not worth effort to
+// spell out which targets have it and which ones do not; see rust#97800.)
+
+// CHECK: declare{{( zeroext)?}} i8 @foreign_fn()
 extern "C" {fn foreign_fn() -> u8;}
 
 // CHECK: !{i32 {{[78]}}, !"PIC Level", i32 2}
diff --git a/src/test/codegen/slice-iter-len-eq-zero.rs b/src/test/codegen/slice-iter-len-eq-zero.rs
index fd19e624cddd..1124028253de 100644
--- a/src/test/codegen/slice-iter-len-eq-zero.rs
+++ b/src/test/codegen/slice-iter-len-eq-zero.rs
@@ -1,5 +1,6 @@
 // no-system-llvm
 // compile-flags: -O
+// ignore-debug: the debug assertions add extra comparisons
 #![crate_type = "lib"]
 
 type Demo = [u8; 3];
@@ -12,3 +13,16 @@ pub fn slice_iter_len_eq_zero(y: std::slice::Iter<'_, Demo>) -> bool {
     // CHECK: ret i1 %2
     y.len() == 0
 }
+
+// CHECK-LABEL: @array_into_iter_len_eq_zero
+#[no_mangle]
+pub fn array_into_iter_len_eq_zero(y: std::array::IntoIter<Demo, 123>) -> bool {
+    // This should be able to just check that the indexes are equal, and not
+    // need any subtractions or comparisons to handle `start > end`.
+
+    // CHECK-NOT: icmp
+    // CHECK-NOT: sub
+    // CHECK: %1 = icmp eq {{i16|i32|i64}}
+    // CHECK: ret i1 %1
+    y.len() == 0
+}
diff --git a/src/test/codegen/slice_as_from_ptr_range.rs b/src/test/codegen/slice_as_from_ptr_range.rs
new file mode 100644
index 000000000000..0e3fefd9728d
--- /dev/null
+++ b/src/test/codegen/slice_as_from_ptr_range.rs
@@ -0,0 +1,23 @@
+// compile-flags: -O
+// only-64bit (because we're using [ui]size)
+// ignore-debug (because the assertions get in the way)
+// min-llvm-version: 15.0 (because this is a relatively new instcombine)
+
+#![crate_type = "lib"]
+#![feature(slice_from_ptr_range)]
+
+// This is intentionally using a non-power-of-two array length,
+// as that's where the optimization differences show up
+
+// CHECK-LABEL: @flatten_via_ptr_range
+#[no_mangle]
+pub fn flatten_via_ptr_range(slice_of_arrays: &[[i32; 13]]) -> &[i32] {
+    // CHECK-NOT: lshr
+    // CHECK-NOT: udiv
+    // CHECK: mul nuw nsw i64 %{{.+}}, 13
+    // CHECK-NOT: lshr
+    // CHECK-NOT: udiv
+    let r = slice_of_arrays.as_ptr_range();
+    let r = r.start.cast()..r.end.cast();
+    unsafe { core::slice::from_ptr_range(r) }
+}
diff --git a/src/test/codegen/some-abis-do-extend-params-to-32-bits.rs b/src/test/codegen/some-abis-do-extend-params-to-32-bits.rs
new file mode 100644
index 000000000000..7fc34af3da72
--- /dev/null
+++ b/src/test/codegen/some-abis-do-extend-params-to-32-bits.rs
@@ -0,0 +1,204 @@
+// compile-flags: -Cno-prepopulate-passes
+
+// revisions:x86_64 i686 aarch64-apple aarch64-windows aarch64-linux arm riscv
+
+//[x86_64] compile-flags: --target x86_64-unknown-uefi
+//[x86_64] needs-llvm-components: x86
+//[i686] compile-flags: --target i686-unknown-linux-musl
+//[i686] needs-llvm-components: x86
+//[aarch64-windows] compile-flags: --target aarch64-pc-windows-msvc
+//[aarch64-windows] needs-llvm-components: aarch64
+//[aarch64-linux] compile-flags: --target aarch64-unknown-linux-gnu
+//[aarch64-linux] needs-llvm-components: aarch64
+//[aarch64-apple] compile-flags: --target aarch64-apple-darwin
+//[aarch64-apple] needs-llvm-components: aarch64
+//[arm] compile-flags: --target armv7r-none-eabi
+//[arm] needs-llvm-components: arm
+//[riscv] compile-flags: --target riscv64gc-unknown-none-elf
+//[riscv] needs-llvm-components: riscv
+
+// See bottom of file for a corresponding C source file that is meant to yield
+// equivalent declarations.
+#![feature(no_core, lang_items)]
+#![crate_type = "lib"]
+#![no_std]
+#![no_core]
+
+#[lang="sized"] trait Sized { }
+#[lang="freeze"] trait Freeze { }
+#[lang="copy"] trait Copy { }
+
+// The patterns in this file are written in the style of a table to make the
+// uniformities and distinctions more apparent.
+//
+//                  ZERO/SIGN-EXTENDING TO 32 BITS            NON-EXTENDING
+//                  ==============================  =======================
+// x86_64:          void @c_arg_u8(i8 zeroext %_a)
+// i686:            void @c_arg_u8(i8 zeroext %_a)
+// aarch64-apple:   void @c_arg_u8(i8 zeroext %_a)
+// aarch64-windows:                                  void @c_arg_u8(i8 %_a)
+// aarch64-linux:                                    void @c_arg_u8(i8 %_a)
+// arm:             void @c_arg_u8(i8 zeroext %_a)
+// riscv:           void @c_arg_u8(i8 zeroext %_a)
+#[no_mangle] pub extern "C" fn c_arg_u8(_a: u8) { }
+
+// x86_64:          void @c_arg_u16(i16 zeroext %_a)
+// i686:            void @c_arg_u16(i16 zeroext %_a)
+// aarch64-apple:   void @c_arg_u16(i16 zeroext %_a)
+// aarch64-windows:                                 void @c_arg_u16(i16 %_a)
+// aarch64-linux:                                   void @c_arg_u16(i16 %_a)
+// arm:             void @c_arg_u16(i16 zeroext %_a)
+// riscv:           void @c_arg_u16(i16 zeroext %_a)
+#[no_mangle] pub extern "C" fn c_arg_u16(_a: u16) { }
+
+// x86_64:          void @c_arg_u32(i32 %_a)
+// i686:            void @c_arg_u32(i32 %_a)
+// aarch64-apple:   void @c_arg_u32(i32 %_a)
+// aarch64-windows:                                 void @c_arg_u32(i32 %_a)
+// aarch64-linux:                                   void @c_arg_u32(i32 %_a)
+// arm:             void @c_arg_u32(i32 %_a)
+// riscv:           void @c_arg_u32(i32 signext %_a)
+#[no_mangle] pub extern "C" fn c_arg_u32(_a: u32) { }
+
+// x86_64:          void @c_arg_u64(i64 %_a)
+// i686:            void @c_arg_u64(i64 %_a)
+// aarch64-apple:   void @c_arg_u64(i64 %_a)
+// aarch64-windows:                                 void @c_arg_u64(i64 %_a)
+// aarch64-linux:                                   void @c_arg_u64(i64 %_a)
+// arm:             void @c_arg_u64(i64 %_a)
+// riscv:           void @c_arg_u64(i64 %_a)
+#[no_mangle] pub extern "C" fn c_arg_u64(_a: u64) { }
+
+// x86_64:          void @c_arg_i8(i8 signext %_a)
+// i686:            void @c_arg_i8(i8 signext %_a)
+// aarch64-apple:   void @c_arg_i8(i8 signext %_a)
+// aarch64-windows:                                  void @c_arg_i8(i8 %_a)
+// aarch64-linux:                                    void @c_arg_i8(i8 %_a)
+// arm:             void @c_arg_i8(i8 signext %_a)
+// riscv:           void @c_arg_i8(i8 signext %_a)
+#[no_mangle] pub extern "C" fn c_arg_i8(_a: i8) { }
+
+// x86_64:          void @c_arg_i16(i16 signext %_a)
+// i686:            void @c_arg_i16(i16 signext %_a)
+// aarch64-apple:   void @c_arg_i16(i16 signext %_a)
+// aarch64-windows:                                 void @c_arg_i16(i16 %_a)
+// aarch64-linux:                                   void @c_arg_i16(i16 %_a)
+// arm:             void @c_arg_i16(i16 signext %_a)
+// riscv:           void @c_arg_i16(i16 signext %_a)
+#[no_mangle] pub extern "C" fn c_arg_i16(_a: i16) { }
+
+// x86_64:          void @c_arg_i32(i32 %_a)
+// i686:            void @c_arg_i32(i32 %_a)
+// aarch64-apple:   void @c_arg_i32(i32 %_a)
+// aarch64-windows:                                 void @c_arg_i32(i32 %_a)
+// aarch64-linux:                                   void @c_arg_i32(i32 %_a)
+// arm:             void @c_arg_i32(i32 %_a)
+// riscv:           void @c_arg_i32(i32 signext %_a)
+#[no_mangle] pub extern "C" fn c_arg_i32(_a: i32) { }
+
+// x86_64:          void @c_arg_i64(i64 %_a)
+// i686:            void @c_arg_i64(i64 %_a)
+// aarch64-apple:   void @c_arg_i64(i64 %_a)
+// aarch64-windows:                                 void @c_arg_i64(i64 %_a)
+// aarch64-linux:                                   void @c_arg_i64(i64 %_a)
+// arm:             void @c_arg_i64(i64 %_a)
+// riscv:           void @c_arg_i64(i64 %_a)
+#[no_mangle] pub extern "C" fn c_arg_i64(_a: i64) { }
+
+// x86_64:          zeroext i8 @c_ret_u8()
+// i686:            zeroext i8 @c_ret_u8()
+// aarch64-apple:   zeroext i8 @c_ret_u8()
+// aarch64-windows:                                 i8 @c_ret_u8()
+// aarch64-linux:                                   i8 @c_ret_u8()
+// arm:             zeroext i8 @c_ret_u8()
+// riscv:           zeroext i8 @c_ret_u8()
+#[no_mangle] pub extern "C" fn c_ret_u8() -> u8 { 0 }
+
+// x86_64:          zeroext i16 @c_ret_u16()
+// i686:            zeroext i16 @c_ret_u16()
+// aarch64-apple:   zeroext i16 @c_ret_u16()
+// aarch64-windows:                                 i16 @c_ret_u16()
+// aarch64-linux:                                   i16 @c_ret_u16()
+// arm:             zeroext i16 @c_ret_u16()
+// riscv:           zeroext i16 @c_ret_u16()
+#[no_mangle] pub extern "C" fn c_ret_u16() -> u16 { 0 }
+
+// x86_64:          i32 @c_ret_u32()
+// i686:            i32 @c_ret_u32()
+// aarch64-apple:   i32 @c_ret_u32()
+// aarch64-windows:                                 i32 @c_ret_u32()
+// aarch64-linux:                                   i32 @c_ret_u32()
+// arm:             i32 @c_ret_u32()
+// riscv:           signext i32 @c_ret_u32()
+#[no_mangle] pub extern "C" fn c_ret_u32() -> u32 { 0 }
+
+// x86_64:          i64 @c_ret_u64()
+// i686:            i64 @c_ret_u64()
+// aarch64-apple:   i64 @c_ret_u64()
+// aarch64-windows:                                 i64 @c_ret_u64()
+// aarch64-linux:                                   i64 @c_ret_u64()
+// arm:             i64 @c_ret_u64()
+// riscv:           i64 @c_ret_u64()
+#[no_mangle] pub extern "C" fn c_ret_u64() -> u64 { 0 }
+
+// x86_64:          signext i8 @c_ret_i8()
+// i686:            signext i8 @c_ret_i8()
+// aarch64-apple:   signext i8 @c_ret_i8()
+// aarch64-windows:                                 i8 @c_ret_i8()
+// aarch64-linux:                                   i8 @c_ret_i8()
+// arm:             signext i8 @c_ret_i8()
+// riscv:           signext i8 @c_ret_i8()
+#[no_mangle] pub extern "C" fn c_ret_i8() -> i8 { 0 }
+
+// x86_64:          signext i16 @c_ret_i16()
+// i686:            signext i16 @c_ret_i16()
+// aarch64-apple:   signext i16 @c_ret_i16()
+// aarch64-windows:                                 i16 @c_ret_i16()
+// aarch64-linux:                                   i16 @c_ret_i16()
+// arm:             signext i16 @c_ret_i16()
+// riscv:           signext i16 @c_ret_i16()
+#[no_mangle] pub extern "C" fn c_ret_i16() -> i16 { 0 }
+
+// x86_64:          i32 @c_ret_i32()
+// i686:            i32 @c_ret_i32()
+// aarch64-apple:   i32 @c_ret_i32()
+// aarch64-windows:                                 i32 @c_ret_i32()
+// aarch64-linux:                                   i32 @c_ret_i32()
+// arm:             i32 @c_ret_i32()
+// riscv:           signext i32 @c_ret_i32()
+#[no_mangle] pub extern "C" fn c_ret_i32() -> i32 { 0 }
+
+// x86_64:          i64 @c_ret_i64()
+// i686:            i64 @c_ret_i64()
+// aarch64-apple:   i64 @c_ret_i64()
+// aarch64-windows:                                 i64 @c_ret_i64()
+// aarch64-linux:                                   i64 @c_ret_i64()
+// arm:             i64 @c_ret_i64()
+// riscv:           i64 @c_ret_i64()
+#[no_mangle] pub extern "C" fn c_ret_i64() -> i64 { 0 }
+
+const C_SOURCE_FILE: &'static str = r##"
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+
+void c_arg_u8(uint8_t _a) { }
+void c_arg_u16(uint16_t _a) { }
+void c_arg_u32(uint32_t _a) { }
+void c_arg_u64(uint64_t _a) { }
+
+void c_arg_i8(int8_t _a) { }
+void c_arg_i16(int16_t _a) { }
+void c_arg_i32(int32_t _a) { }
+void c_arg_i64(int64_t _a) { }
+
+uint8_t  c_ret_u8()  { return 0; }
+uint16_t c_ret_u16() { return 0; }
+uint32_t c_ret_u32() { return 0; }
+uint64_t c_ret_u64() { return 0; }
+
+int8_t   c_ret_i8()  { return 0; }
+int16_t  c_ret_i16() { return 0; }
+int32_t  c_ret_i32() { return 0; }
+int64_t  c_ret_i64() { return 0; }
+"##;
diff --git a/src/test/codegen/unwind-abis/aapcs-unwind-abi.rs b/src/test/codegen/unwind-abis/aapcs-unwind-abi.rs
index 1fe048068601..c092e28a05ac 100644
--- a/src/test/codegen/unwind-abis/aapcs-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/aapcs-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `aapcs` and
+// Test that `nounwind` attributes are correctly applied to exported `aapcs` and
 // `aapcs-unwind` extern functions. `aapcs-unwind` functions MUST NOT have this attribute. We
 // disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs b/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs
index e817d5715a18..8447bbeb1ed2 100644
--- a/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs
+++ b/src/test/codegen/unwind-abis/c-unwind-abi-panic-abort.rs
@@ -1,6 +1,6 @@
 // compile-flags: -C panic=abort
 
-// Test that `nounwind` atributes are also applied to extern `C-unwind` Rust functions
+// Test that `nounwind` attributes are also applied to extern `C-unwind` Rust functions
 // when the code is compiled with `panic=abort`.
 
 #![crate_type = "lib"]
diff --git a/src/test/codegen/unwind-abis/c-unwind-abi.rs b/src/test/codegen/unwind-abis/c-unwind-abi.rs
index f15765367532..e258dbcacd22 100644
--- a/src/test/codegen/unwind-abis/c-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/c-unwind-abi.rs
@@ -1,6 +1,6 @@
 // compile-flags: -C opt-level=0
 
-// Test that `nounwind` atributes are correctly applied to exported `C` and `C-unwind` extern
+// Test that `nounwind` attributes are correctly applied to exported `C` and `C-unwind` extern
 // functions. `C-unwind` functions MUST NOT have this attribute. We disable optimizations above
 // to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/cdecl-unwind-abi.rs b/src/test/codegen/unwind-abis/cdecl-unwind-abi.rs
index 52e0d2d6e025..19a7228839ab 100644
--- a/src/test/codegen/unwind-abis/cdecl-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/cdecl-unwind-abi.rs
@@ -1,6 +1,6 @@
 // compile-flags: -C opt-level=0
 
-// Test that `nounwind` atributes are correctly applied to exported `cdecl` and
+// Test that `nounwind` attributes are correctly applied to exported `cdecl` and
 // `cdecl-unwind` extern functions. `cdecl-unwind` functions MUST NOT have this attribute. We
 // disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/fastcall-unwind-abi.rs b/src/test/codegen/unwind-abis/fastcall-unwind-abi.rs
index ed23235ebfa8..b74099a5d965 100644
--- a/src/test/codegen/unwind-abis/fastcall-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/fastcall-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `fastcall` and
+// Test that `nounwind` attributes are correctly applied to exported `fastcall` and
 // `fastcall-unwind` extern functions. `fastcall-unwind` functions MUST NOT have this attribute. We
 // disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/nounwind-on-stable-panic-abort.rs b/src/test/codegen/unwind-abis/nounwind-on-stable-panic-abort.rs
index 9a4b3d3b4848..106d593b21de 100644
--- a/src/test/codegen/unwind-abis/nounwind-on-stable-panic-abort.rs
+++ b/src/test/codegen/unwind-abis/nounwind-on-stable-panic-abort.rs
@@ -3,7 +3,7 @@
 
 #![crate_type = "lib"]
 
-// We disable optimizations to prevent LLVM from infering the attribute.
+// We disable optimizations to prevent LLVM from inferring the attribute.
 
 // CHECK: Function Attrs:{{.*}}nounwind
 // CHECK-NEXT: @foo
diff --git a/src/test/codegen/unwind-abis/nounwind-on-stable-panic-unwind.rs b/src/test/codegen/unwind-abis/nounwind-on-stable-panic-unwind.rs
index 2783c83d3efe..c1c5bbdda345 100644
--- a/src/test/codegen/unwind-abis/nounwind-on-stable-panic-unwind.rs
+++ b/src/test/codegen/unwind-abis/nounwind-on-stable-panic-unwind.rs
@@ -3,7 +3,7 @@
 
 #![crate_type = "lib"]
 
-// We disable optimizations to prevent LLVM from infering the attribute.
+// We disable optimizations to prevent LLVM from inferring the attribute.
 
 extern "C" {
     fn bar();
diff --git a/src/test/codegen/unwind-abis/nounwind.rs b/src/test/codegen/unwind-abis/nounwind.rs
index cfc140361f62..c46d717331b4 100644
--- a/src/test/codegen/unwind-abis/nounwind.rs
+++ b/src/test/codegen/unwind-abis/nounwind.rs
@@ -4,7 +4,7 @@
 #![crate_type = "lib"]
 #![feature(c_unwind)]
 
-// We disable optimizations to prevent LLVM from infering the attribute.
+// We disable optimizations to prevent LLVM from inferring the attribute.
 
 // CHECK: Function Attrs:{{.*}}nounwind
 // CHECK-NEXT: @foo
diff --git a/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs b/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs
index f1dff27ad67b..8eff0719f8fa 100644
--- a/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/stdcall-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `stdcall` and `stdcall-unwind`
+// Test that `nounwind` attributes are correctly applied to exported `stdcall` and `stdcall-unwind`
 // extern functions. `stdcall-unwind` functions MUST NOT have this attribute. We disable
 // optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/system-unwind-abi.rs b/src/test/codegen/unwind-abis/system-unwind-abi.rs
index c4d51328352c..2591c1d48143 100644
--- a/src/test/codegen/unwind-abis/system-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/system-unwind-abi.rs
@@ -1,6 +1,6 @@
 // compile-flags: -C opt-level=0
 
-// Test that `nounwind` atributes are correctly applied to exported `system` and `system-unwind`
+// Test that `nounwind` attributes are correctly applied to exported `system` and `system-unwind`
 // extern functions. `system-unwind` functions MUST NOT have this attribute. We disable
 // optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/sysv64-unwind-abi.rs b/src/test/codegen/unwind-abis/sysv64-unwind-abi.rs
index a38736f2a1f9..694fde17c3cb 100644
--- a/src/test/codegen/unwind-abis/sysv64-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/sysv64-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `sysv64` and
+// Test that `nounwind` attributes are correctly applied to exported `sysv64` and
 // `sysv64-unwind` extern functions. `sysv64-unwind` functions MUST NOT have this attribute. We
 // disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs b/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs
index d2cf041b72d2..7e81367fc5b7 100644
--- a/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/thiscall-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `thiscall` and
+// Test that `nounwind` attributes are correctly applied to exported `thiscall` and
 // `thiscall-unwind` extern functions. `thiscall-unwind` functions MUST NOT have this attribute. We
 // disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/vectorcall-unwind-abi.rs b/src/test/codegen/unwind-abis/vectorcall-unwind-abi.rs
index 0fb9612a5e4e..d7eca2a97000 100644
--- a/src/test/codegen/unwind-abis/vectorcall-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/vectorcall-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `vectorcall` and
+// Test that `nounwind` attributes are correctly applied to exported `vectorcall` and
 // `vectorcall-unwind` extern functions. `vectorcall-unwind` functions MUST NOT have this attribute.
 // We disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-abis/win64-unwind-abi.rs b/src/test/codegen/unwind-abis/win64-unwind-abi.rs
index 5d8482da6305..6591348c35d3 100644
--- a/src/test/codegen/unwind-abis/win64-unwind-abi.rs
+++ b/src/test/codegen/unwind-abis/win64-unwind-abi.rs
@@ -5,7 +5,7 @@
 #[lang="sized"]
 trait Sized { }
 
-// Test that `nounwind` atributes are correctly applied to exported `win64` and
+// Test that `nounwind` attributes are correctly applied to exported `win64` and
 // `win64-unwind` extern functions. `win64-unwind` functions MUST NOT have this attribute. We
 // disable optimizations above to prevent LLVM from inferring the attribute.
 
diff --git a/src/test/codegen/unwind-extern-exports.rs b/src/test/codegen/unwind-extern-exports.rs
index c939235fb500..6ac3c079f81b 100644
--- a/src/test/codegen/unwind-extern-exports.rs
+++ b/src/test/codegen/unwind-extern-exports.rs
@@ -5,7 +5,7 @@
 #![feature(c_unwind)]
 
 // Make sure these all do *not* get the attribute.
-// We disable optimizations to prevent LLVM from infering the attribute.
+// We disable optimizations to prevent LLVM from inferring the attribute.
 // CHECK-NOT: nounwind
 
 // "C" ABI
diff --git a/src/test/debuginfo/collapse-debuginfo-no-attr-flag.rs b/src/test/debuginfo/collapse-debuginfo-no-attr-flag.rs
new file mode 100644
index 000000000000..413f6120105e
--- /dev/null
+++ b/src/test/debuginfo/collapse-debuginfo-no-attr-flag.rs
@@ -0,0 +1,61 @@
+// ignore-lldb
+#![feature(collapse_debuginfo)]
+
+// Test that line numbers are not replaced with those of the outermost expansion site when the
+// `collapse_debuginfo` is active, `-Zdebug-macros` is provided and `#[collapse_debuginfo]` not
+// being used.
+
+// compile-flags:-g -Zdebug-macros
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc1[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc2[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc3[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc4[...]
+// gdb-command:continue
+
+fn one() {
+    println!("one");
+}
+fn two() {
+    println!("two");
+}
+fn three() {
+    println!("three");
+}
+fn four() {
+    println!("four");
+}
+
+macro_rules! outer {
+    ($b:block) => {
+        one(); // #loc1
+        inner!();
+        $b
+    };
+}
+
+macro_rules! inner {
+    () => {
+        two(); // #loc2
+    };
+}
+
+fn main() {
+    let ret = 0; // #break
+    outer!({
+        three(); // #loc3
+        four(); // #loc4
+    });
+    std::process::exit(ret);
+}
diff --git a/src/test/debuginfo/collapse-debuginfo-no-attr.rs b/src/test/debuginfo/collapse-debuginfo-no-attr.rs
new file mode 100644
index 000000000000..230c8795be36
--- /dev/null
+++ b/src/test/debuginfo/collapse-debuginfo-no-attr.rs
@@ -0,0 +1,60 @@
+// ignore-lldb
+#![feature(collapse_debuginfo)]
+
+// Test that line numbers are not replaced with those of the outermost expansion site when the
+// `collapse_debuginfo` feature is active and the attribute is not provided.
+
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc1[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc2[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc3[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc4[...]
+// gdb-command:continue
+
+fn one() {
+    println!("one");
+}
+fn two() {
+    println!("two");
+}
+fn three() {
+    println!("three");
+}
+fn four() {
+    println!("four");
+}
+
+macro_rules! outer {
+    ($b:block) => {
+        one(); // #loc1
+        inner!();
+        $b
+    };
+}
+
+macro_rules! inner {
+    () => {
+        two(); // #loc2
+    };
+}
+
+fn main() {
+    let ret = 0; // #break
+    outer!({
+        three(); // #loc3
+        four(); // #loc4
+    });
+    std::process::exit(ret);
+}
diff --git a/src/test/debuginfo/collapse-debuginfo-with-attr-flag.rs b/src/test/debuginfo/collapse-debuginfo-with-attr-flag.rs
new file mode 100644
index 000000000000..183cf537e85d
--- /dev/null
+++ b/src/test/debuginfo/collapse-debuginfo-with-attr-flag.rs
@@ -0,0 +1,63 @@
+// ignore-lldb
+#![feature(collapse_debuginfo)]
+
+// Test that line numbers are not replaced with those of the outermost expansion site when the
+// `collapse_debuginfo` is active and `-Zdebug-macros` is provided, despite `#[collapse_debuginfo]`
+// being used.
+
+// compile-flags:-g -Zdebug-macros
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc1[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc2[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc3[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc4[...]
+// gdb-command:continue
+
+fn one() {
+    println!("one");
+}
+fn two() {
+    println!("two");
+}
+fn three() {
+    println!("three");
+}
+fn four() {
+    println!("four");
+}
+
+#[collapse_debuginfo]
+macro_rules! outer {
+    ($b:block) => {
+        one(); // #loc1
+        inner!();
+        $b
+    };
+}
+
+#[collapse_debuginfo]
+macro_rules! inner {
+    () => {
+        two(); // #loc2
+    };
+}
+
+fn main() {
+    let ret = 0; // #break
+    outer!({
+        three(); // #loc3
+        four(); // #loc4
+    });
+    std::process::exit(ret);
+}
diff --git a/src/test/debuginfo/collapse-debuginfo-with-attr.rs b/src/test/debuginfo/collapse-debuginfo-with-attr.rs
new file mode 100644
index 000000000000..34d03c18bc72
--- /dev/null
+++ b/src/test/debuginfo/collapse-debuginfo-with-attr.rs
@@ -0,0 +1,59 @@
+// ignore-lldb
+#![feature(collapse_debuginfo)]
+
+// Test that line numbers are replaced with those of the outermost expansion site when the
+// `collapse_debuginfo` feature is active and the attribute is provided.
+
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc1[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc2[...]
+// gdb-command:next
+// gdb-command:frame
+// gdb-check:[...]#loc3[...]
+// gdb-command:continue
+
+fn one() {
+    println!("one");
+}
+fn two() {
+    println!("two");
+}
+fn three() {
+    println!("three");
+}
+fn four() {
+    println!("four");
+}
+
+#[collapse_debuginfo]
+macro_rules! outer {
+    ($b:block) => {
+        one();
+        inner!();
+        $b
+    };
+}
+
+#[collapse_debuginfo]
+macro_rules! inner {
+    () => {
+        two();
+    };
+}
+
+fn main() {
+    let ret = 0; // #break
+    outer!({ // #loc1
+        three(); // #loc2
+        four(); // #loc3
+    });
+    std::process::exit(ret);
+}
diff --git a/src/test/debuginfo/msvc-pretty-enums.rs b/src/test/debuginfo/msvc-pretty-enums.rs
index 45d5ddf5c0eb..7f1be6f27847 100644
--- a/src/test/debuginfo/msvc-pretty-enums.rs
+++ b/src/test/debuginfo/msvc-pretty-enums.rs
@@ -53,8 +53,8 @@
 // cdb-command: dx niche128_none
 // cdb-check: niche128_none    : None [Type: enum2$<core::option::Option<core::num::nonzero::NonZeroI128> >]
 
-// cdb-command: dx wrapping_niche128_dataful
-// cdb-check: wrapping_niche128_dataful : X [Type: enum2$<msvc_pretty_enums::Wrapping128Niche>]
+// cdb-command: dx wrapping_niche128_untagged
+// cdb-check: wrapping_niche128_untagged : X [Type: enum2$<msvc_pretty_enums::Wrapping128Niche>]
 // cdb-check:    [+0x[...]] __0              [Type: msvc_pretty_enums::Wrapping128]
 
 // cdb-command: dx wrapping_niche128_none1
@@ -213,7 +213,7 @@ fn main() {
     let niche128_some = Some(NonZeroI128::new(123456).unwrap());
     let niche128_none: Option<NonZeroI128> = None;
 
-    let wrapping_niche128_dataful =
+    let wrapping_niche128_untagged =
         unsafe { Wrapping128Niche::X(Wrapping128(340282366920938463463374607431768211454)) };
     let wrapping_niche128_none1 = Wrapping128Niche::Y;
     let wrapping_niche128_none2 = Wrapping128Niche::Z;
diff --git a/src/test/incremental/const-generics/hash-tyvid-regression-1.rs b/src/test/incremental/const-generics/hash-tyvid-regression-1.rs
index 53358b183cbf..5ff7b19d8945 100644
--- a/src/test/incremental/const-generics/hash-tyvid-regression-1.rs
+++ b/src/test/incremental/const-generics/hash-tyvid-regression-1.rs
@@ -9,6 +9,7 @@ where
     use std::convert::TryFrom;
     <[T; N.get()]>::try_from(())
     //~^ error: the trait bound
+    //~| error: the trait bound
     //~| error: mismatched types
 }
 
diff --git a/src/test/incremental/hygiene/load_cached_hygiene.rs b/src/test/incremental/hygiene/load_cached_hygiene.rs
index 8124141418bc..355d33458524 100644
--- a/src/test/incremental/hygiene/load_cached_hygiene.rs
+++ b/src/test/incremental/hygiene/load_cached_hygiene.rs
@@ -2,7 +2,7 @@
 // compile-flags: -Z query-dep-graph
 // aux-build:cached_hygiene.rs
 
-// This tests the folllowing scenario
+// This tests the following scenario
 // 1. A foreign crate is compiled with incremental compilation.
 //    This causes hygiene information to be saved to the incr cache.
 // 2. One function is the foreign crate is modified. This causes the
diff --git a/src/test/incremental/issue-100521-change-struct-name-assocty.rs b/src/test/incremental/issue-100521-change-struct-name-assocty.rs
new file mode 100644
index 000000000000..7f8d1e608819
--- /dev/null
+++ b/src/test/incremental/issue-100521-change-struct-name-assocty.rs
@@ -0,0 +1,65 @@
+// revisions: rpass1 rpass2
+
+pub fn foo() {
+    bar();
+    baz::<()>();
+}
+
+fn bar()
+where
+    <() as Table>::AllColumns:,
+{
+}
+
+fn baz<W>()
+where
+    W: AsQuery,
+    <W as AsQuery>::Query:,
+{
+}
+
+trait AsQuery {
+    type Query;
+}
+
+trait UnimplementedTrait {}
+
+impl<T> AsQuery for T
+where
+    T: UnimplementedTrait,
+{
+    type Query = ();
+}
+
+struct Wrapper<Expr>(Expr);
+
+impl<Ret> AsQuery for Wrapper<Ret> {
+    type Query = ();
+}
+
+impl AsQuery for ()
+where
+    Wrapper<<() as Table>::AllColumns>: AsQuery,
+{
+    type Query = ();
+}
+
+trait Table {
+    type AllColumns;
+}
+
+#[cfg(rpass1)]
+impl Table for () {
+    type AllColumns = Checksum1;
+}
+#[cfg(rpass1)]
+struct Checksum1;
+
+#[cfg(rpass2)]
+impl Table for () {
+    type AllColumns = Checksum2;
+}
+#[cfg(rpass2)]
+struct Checksum2;
+
+fn main() {}
diff --git a/src/test/incremental/issue-49043.rs b/src/test/incremental/issue-49043.rs
index 50d8fb869307..8d13718b8d84 100644
--- a/src/test/incremental/issue-49043.rs
+++ b/src/test/incremental/issue-49043.rs
@@ -1,5 +1,5 @@
 // Regression test for hashing involving canonical variables.  In this
-// test -- which has an intensional error -- the type of the value
+// test -- which has an intentional error -- the type of the value
 // being dropped winds up including a type variable. Canonicalization
 // would then produce a `?0` which -- in turn -- triggered an ICE in
 // hashing.
diff --git a/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs b/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs
index 4d48a5f0ac52..95f3b8ae4d98 100644
--- a/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs
+++ b/src/test/incremental/thinlto/cgu_invalidated_when_export_added.rs
@@ -3,7 +3,7 @@
 
 // rust-lang/rust#69798:
 //
-// This is analgous to cgu_invalidated_when_import_added, but it covers a
+// This is analogous to cgu_invalidated_when_import_added, but it covers a
 // problem uncovered where a change to the *export* set caused a link failure
 // when reusing post-LTO optimized object code.
 
diff --git a/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs b/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs
index e85b4856f3a9..e86ebd354b1a 100644
--- a/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs
+++ b/src/test/incremental/thinlto/cgu_invalidated_when_export_removed.rs
@@ -3,7 +3,7 @@
 
 // rust-lang/rust#69798:
 //
-// This is analgous to cgu_invalidated_when_export_added, but it covers the
+// This is analogous to cgu_invalidated_when_export_added, but it covers the
 // other direction. This is analogous to cgu_invalidated_when_import_added: we
 // include it, because it may uncover bugs in variant implementation strategies.
 
diff --git a/src/test/mir-opt/array-index-is-temporary.rs b/src/test/mir-opt/array-index-is-temporary.rs
index 0e4c486e4640..e7bde81d4ca3 100644
--- a/src/test/mir-opt/array-index-is-temporary.rs
+++ b/src/test/mir-opt/array-index-is-temporary.rs
@@ -7,7 +7,7 @@ unsafe fn foo(z: *mut usize) -> u32 {
     99
 }
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.mir
 fn main() {
     let mut x = [42, 43, 44];
diff --git a/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.64bit.mir b/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.64bit.mir
deleted file mode 100644
index 27f883ed321a..000000000000
--- a/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.64bit.mir
+++ /dev/null
@@ -1,64 +0,0 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
-
-fn main() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/array-index-is-temporary.rs:+0:11: +0:11
-    let mut _1: [u32; 3];                // in scope 0 at $DIR/array-index-is-temporary.rs:+1:9: +1:14
-    let mut _4: &mut usize;              // in scope 0 at $DIR/array-index-is-temporary.rs:+3:25: +3:31
-    let mut _5: u32;                     // in scope 0 at $DIR/array-index-is-temporary.rs:+4:12: +4:29
-    let mut _6: *mut usize;              // in scope 0 at $DIR/array-index-is-temporary.rs:+4:25: +4:26
-    let _7: usize;                       // in scope 0 at $DIR/array-index-is-temporary.rs:+4:7: +4:8
-    let mut _8: usize;                   // in scope 0 at $DIR/array-index-is-temporary.rs:+4:5: +4:9
-    let mut _9: bool;                    // in scope 0 at $DIR/array-index-is-temporary.rs:+4:5: +4:9
-    scope 1 {
-        debug x => _1;                   // in scope 1 at $DIR/array-index-is-temporary.rs:+1:9: +1:14
-        let mut _2: usize;               // in scope 1 at $DIR/array-index-is-temporary.rs:+2:9: +2:14
-        scope 2 {
-            debug y => _2;               // in scope 2 at $DIR/array-index-is-temporary.rs:+2:9: +2:14
-            let _3: *mut usize;          // in scope 2 at $DIR/array-index-is-temporary.rs:+3:9: +3:10
-            scope 3 {
-                debug z => _3;           // in scope 3 at $DIR/array-index-is-temporary.rs:+3:9: +3:10
-                scope 4 {
-                }
-            }
-        }
-    }
-
-    bb0: {
-        StorageLive(_1);                 // scope 0 at $DIR/array-index-is-temporary.rs:+1:9: +1:14
-        _1 = [const 42_u32, const 43_u32, const 44_u32]; // scope 0 at $DIR/array-index-is-temporary.rs:+1:17: +1:29
-        StorageLive(_2);                 // scope 1 at $DIR/array-index-is-temporary.rs:+2:9: +2:14
-        _2 = const 1_usize;              // scope 1 at $DIR/array-index-is-temporary.rs:+2:17: +2:18
-        StorageLive(_3);                 // scope 2 at $DIR/array-index-is-temporary.rs:+3:9: +3:10
-        StorageLive(_4);                 // scope 2 at $DIR/array-index-is-temporary.rs:+3:25: +3:31
-        _4 = &mut _2;                    // scope 2 at $DIR/array-index-is-temporary.rs:+3:25: +3:31
-        _3 = &raw mut (*_4);             // scope 2 at $DIR/array-index-is-temporary.rs:+3:25: +3:31
-        StorageDead(_4);                 // scope 2 at $DIR/array-index-is-temporary.rs:+3:31: +3:32
-        StorageLive(_5);                 // scope 3 at $DIR/array-index-is-temporary.rs:+4:12: +4:29
-        StorageLive(_6);                 // scope 4 at $DIR/array-index-is-temporary.rs:+4:25: +4:26
-        _6 = _3;                         // scope 4 at $DIR/array-index-is-temporary.rs:+4:25: +4:26
-        _5 = foo(move _6) -> bb1;        // scope 4 at $DIR/array-index-is-temporary.rs:+4:21: +4:27
-                                         // mir::Constant
-                                         // + span: $DIR/array-index-is-temporary.rs:16:21: 16:24
-                                         // + literal: Const { ty: unsafe fn(*mut usize) -> u32 {foo}, val: Value(<ZST>) }
-    }
-
-    bb1: {
-        StorageDead(_6);                 // scope 4 at $DIR/array-index-is-temporary.rs:+4:26: +4:27
-        StorageLive(_7);                 // scope 3 at $DIR/array-index-is-temporary.rs:+4:7: +4:8
-        _7 = _2;                         // scope 3 at $DIR/array-index-is-temporary.rs:+4:7: +4:8
-        _8 = Len(_1);                    // scope 3 at $DIR/array-index-is-temporary.rs:+4:5: +4:9
-        _9 = Lt(_7, _8);                 // scope 3 at $DIR/array-index-is-temporary.rs:+4:5: +4:9
-        assert(move _9, "index out of bounds: the length is {} but the index is {}", move _8, _7) -> bb2; // scope 3 at $DIR/array-index-is-temporary.rs:+4:5: +4:9
-    }
-
-    bb2: {
-        _1[_7] = move _5;                // scope 3 at $DIR/array-index-is-temporary.rs:+4:5: +4:29
-        StorageDead(_5);                 // scope 3 at $DIR/array-index-is-temporary.rs:+4:28: +4:29
-        StorageDead(_7);                 // scope 3 at $DIR/array-index-is-temporary.rs:+4:29: +4:30
-        _0 = const ();                   // scope 0 at $DIR/array-index-is-temporary.rs:+0:11: +5:2
-        StorageDead(_3);                 // scope 2 at $DIR/array-index-is-temporary.rs:+5:1: +5:2
-        StorageDead(_2);                 // scope 1 at $DIR/array-index-is-temporary.rs:+5:1: +5:2
-        StorageDead(_1);                 // scope 0 at $DIR/array-index-is-temporary.rs:+5:1: +5:2
-        return;                          // scope 0 at $DIR/array-index-is-temporary.rs:+5:2: +5:2
-    }
-}
diff --git a/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.32bit.mir b/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.mir
similarity index 100%
rename from src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.32bit.mir
rename to src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.mir
diff --git a/src/test/mir-opt/combine_clone_of_primitives.{impl#0}-clone.InstCombine.diff b/src/test/mir-opt/combine_clone_of_primitives.{impl#0}-clone.InstCombine.diff
index bde2f04fac9f..6f01553eef6d 100644
--- a/src/test/mir-opt/combine_clone_of_primitives.{impl#0}-clone.InstCombine.diff
+++ b/src/test/mir-opt/combine_clone_of_primitives.{impl#0}-clone.InstCombine.diff
@@ -24,7 +24,7 @@
           _2 = <T as Clone>::clone(move _3) -> bb1; // scope 0 at $DIR/combine_clone_of_primitives.rs:8:5: 8:9
                                            // mir::Constant
                                            // + span: $DIR/combine_clone_of_primitives.rs:8:5: 8:9
-                                           // + literal: Const { ty: for<'r> fn(&'r T) -> T {<T as Clone>::clone}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a T) -> T {<T as Clone>::clone}, val: Value(<ZST>) }
       }
   
       bb1: {
@@ -37,7 +37,7 @@
 -         _5 = <u64 as Clone>::clone(move _6) -> [return: bb2, unwind: bb4]; // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
 -                                          // mir::Constant
 -                                          // + span: $DIR/combine_clone_of_primitives.rs:9:5: 9:11
--                                          // + literal: Const { ty: for<'r> fn(&'r u64) -> u64 {<u64 as Clone>::clone}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(&'a u64) -> u64 {<u64 as Clone>::clone}, val: Value(<ZST>) }
 +         _6 = _7;                         // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
 +         _5 = (*_6);                      // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
 +         goto -> bb2;                     // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
@@ -53,7 +53,7 @@
 -         _8 = <[f32; 3] as Clone>::clone(move _9) -> [return: bb3, unwind: bb4]; // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
 -                                          // mir::Constant
 -                                          // + span: $DIR/combine_clone_of_primitives.rs:10:5: 10:16
--                                          // + literal: Const { ty: for<'r> fn(&'r [f32; 3]) -> [f32; 3] {<[f32; 3] as Clone>::clone}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(&'a [f32; 3]) -> [f32; 3] {<[f32; 3] as Clone>::clone}, val: Value(<ZST>) }
 +         _9 = _10;                        // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
 +         _8 = (*_9);                      // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
 +         goto -> bb3;                     // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
diff --git a/src/test/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff b/src/test/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff
index b5439d9d2393..f8a7c687e124 100644
--- a/src/test/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff
+++ b/src/test/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff
@@ -17,7 +17,7 @@
 -         StorageLive(_4);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:32: +0:34
 -         StorageLive(_5);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:33: +0:34
 -         _5 = const {alloc1: &i32};       // scope 0 at $DIR/const-promotion-extern-static.rs:+0:33: +0:34
-+         _6 = const BAR::promoted[0];     // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:44
++         _6 = const _;                    // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:44
                                            // mir::Constant
 -                                          // + span: $DIR/const-promotion-extern-static.rs:9:33: 9:34
 -                                          // + literal: Const { ty: &i32, val: Value(Scalar(alloc1)) }
@@ -33,18 +33,18 @@
           _0 = core::slice::<impl [&i32]>::as_ptr(move _1) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:44
                                            // mir::Constant
                                            // + span: $DIR/const-promotion-extern-static.rs:9:36: 9:42
-                                           // + literal: Const { ty: for<'r> fn(&'r [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
       }
   
       bb1: {
 -         StorageDead(_5);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:43: +0:44
 -         StorageDead(_3);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:43: +0:44
           StorageDead(_1);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:43: +0:44
-          return;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:44
+          return;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:45
       }
   
       bb2 (cleanup): {
-          resume;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:44
+          resume;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:45
       }
 - }
 - 
diff --git a/src/test/mir-opt/const_promotion_extern_static.BOP.mir_map.0.mir b/src/test/mir-opt/const_promotion_extern_static.BOP.mir_map.0.mir
index 20d73afda271..90920fbe7f80 100644
--- a/src/test/mir-opt/const_promotion_extern_static.BOP.mir_map.0.mir
+++ b/src/test/mir-opt/const_promotion_extern_static.BOP.mir_map.0.mir
@@ -12,6 +12,6 @@ static BOP: &i32 = {
         _1 = &_2;                        // scope 0 at $DIR/const-promotion-extern-static.rs:+0:20: +0:23
         _0 = &(*_1);                     // scope 0 at $DIR/const-promotion-extern-static.rs:+0:20: +0:23
         StorageDead(_1);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:22: +0:23
-        return;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:23
+        return;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:24
     }
 }
diff --git a/src/test/mir-opt/const_promotion_extern_static.FOO.PromoteTemps.diff b/src/test/mir-opt/const_promotion_extern_static.FOO.PromoteTemps.diff
index 4df4c9636a54..e938ca28af5d 100644
--- a/src/test/mir-opt/const_promotion_extern_static.FOO.PromoteTemps.diff
+++ b/src/test/mir-opt/const_promotion_extern_static.FOO.PromoteTemps.diff
@@ -19,7 +19,7 @@
 -         StorageLive(_4);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:32: +0:45
 -         StorageLive(_5);                 // scope 1 at $DIR/const-promotion-extern-static.rs:+0:42: +0:43
 -         _5 = const {alloc3: *const i32}; // scope 1 at $DIR/const-promotion-extern-static.rs:+0:42: +0:43
-+         _6 = const FOO::promoted[0];     // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:55
++         _6 = const _;                    // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:55
                                            // mir::Constant
 -                                          // + span: $DIR/const-promotion-extern-static.rs:13:42: 13:43
 -                                          // + literal: Const { ty: *const i32, val: Value(Scalar(alloc3)) }
@@ -35,18 +35,18 @@
           _0 = core::slice::<impl [&i32]>::as_ptr(move _1) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:55
                                            // mir::Constant
                                            // + span: $DIR/const-promotion-extern-static.rs:13:47: 13:53
-                                           // + literal: Const { ty: for<'r> fn(&'r [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
       }
   
       bb1: {
 -         StorageDead(_5);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:54: +0:55
 -         StorageDead(_3);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:54: +0:55
           StorageDead(_1);                 // scope 0 at $DIR/const-promotion-extern-static.rs:+0:54: +0:55
-          return;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:55
+          return;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:56
       }
   
       bb2 (cleanup): {
-          resume;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:55
+          resume;                          // scope 0 at $DIR/const-promotion-extern-static.rs:+0:1: +0:56
       }
   }
 - 
diff --git a/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.32bit.diff b/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.32bit.diff
index 55348883810f..c27b19679a83 100644
--- a/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.32bit.diff
+++ b/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.32bit.diff
@@ -25,7 +25,7 @@
           StorageLive(_1);                 // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:9: +1:10
           StorageLive(_2);                 // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
           StorageLive(_3);                 // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
-          _9 = const main::promoted[0];    // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
+          _9 = const _;                    // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
                                            // mir::Constant
                                            // + span: $DIR/bad_op_unsafe_oob_for_slices.rs:5:25: 5:35
                                            // + literal: Const { ty: &[i32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.64bit.diff b/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.64bit.diff
index 55348883810f..c27b19679a83 100644
--- a/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.64bit.diff
+++ b/src/test/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.ConstProp.64bit.diff
@@ -25,7 +25,7 @@
           StorageLive(_1);                 // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:9: +1:10
           StorageLive(_2);                 // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
           StorageLive(_3);                 // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
-          _9 = const main::promoted[0];    // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
+          _9 = const _;                    // scope 0 at $DIR/bad_op_unsafe_oob_for_slices.rs:+1:25: +1:35
                                            // mir::Constant
                                            // + span: $DIR/bad_op_unsafe_oob_for_slices.rs:5:25: 5:35
                                            // + literal: Const { ty: &[i32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/const_prop_fails_gracefully.main.ConstProp.diff b/src/test/mir-opt/const_prop/const_prop_fails_gracefully.main.ConstProp.diff
index 2cb071deab13..bea7114c7df3 100644
--- a/src/test/mir-opt/const_prop/const_prop_fails_gracefully.main.ConstProp.diff
+++ b/src/test/mir-opt/const_prop/const_prop_fails_gracefully.main.ConstProp.diff
@@ -16,7 +16,7 @@
           StorageLive(_1);                 // scope 0 at $DIR/const_prop_fails_gracefully.rs:+2:9: +2:10
           StorageLive(_2);                 // scope 0 at $DIR/const_prop_fails_gracefully.rs:+2:13: +2:30
           StorageLive(_3);                 // scope 0 at $DIR/const_prop_fails_gracefully.rs:+2:13: +2:16
-          _3 = const FOO;                  // scope 0 at $DIR/const_prop_fails_gracefully.rs:+2:13: +2:16
+          _3 = const _;                    // scope 0 at $DIR/const_prop_fails_gracefully.rs:+2:13: +2:16
                                            // mir::Constant
                                            // + span: $DIR/const_prop_fails_gracefully.rs:8:13: 8:16
                                            // + literal: Const { ty: &i32, val: Unevaluated(FOO, [], None) }
diff --git a/src/test/mir-opt/const_prop/control_flow_simplification.hello.ConstProp.diff b/src/test/mir-opt/const_prop/control_flow_simplification.hello.ConstProp.diff
index 5f4df0d883bc..a07bdd99825d 100644
--- a/src/test/mir-opt/const_prop/control_flow_simplification.hello.ConstProp.diff
+++ b/src/test/mir-opt/const_prop/control_flow_simplification.hello.ConstProp.diff
@@ -8,9 +8,8 @@
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/control-flow-simplification.rs:+1:8: +1:21
--         _1 = const <bool as NeedsDrop>::NEEDS; // scope 0 at $DIR/control-flow-simplification.rs:+1:8: +1:21
+          _1 = const _;                    // scope 0 at $DIR/control-flow-simplification.rs:+1:8: +1:21
 -         switchInt(move _1) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/control-flow-simplification.rs:+1:8: +1:21
-+         _1 = const false;                // scope 0 at $DIR/control-flow-simplification.rs:+1:8: +1:21
 +         switchInt(const false) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/control-flow-simplification.rs:+1:8: +1:21
       }
   
diff --git a/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff b/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff
index c8b09220f1e4..09ce67ff15dd 100644
--- a/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff
+++ b/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff
@@ -11,7 +11,7 @@
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/ref_deref.rs:+1:5: +1:10
           StorageLive(_2);                 // scope 0 at $DIR/ref_deref.rs:+1:6: +1:10
-          _4 = const main::promoted[0];    // scope 0 at $DIR/ref_deref.rs:+1:6: +1:10
+          _4 = const _;                    // scope 0 at $DIR/ref_deref.rs:+1:6: +1:10
                                            // mir::Constant
                                            // + span: $DIR/ref_deref.rs:5:6: 5:10
                                            // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/ref_deref.main.PromoteTemps.diff b/src/test/mir-opt/const_prop/ref_deref.main.PromoteTemps.diff
index d141d2cf87bb..902cd7850311 100644
--- a/src/test/mir-opt/const_prop/ref_deref.main.PromoteTemps.diff
+++ b/src/test/mir-opt/const_prop/ref_deref.main.PromoteTemps.diff
@@ -14,7 +14,7 @@
 -         StorageLive(_3);                 // scope 0 at $DIR/ref_deref.rs:+1:8: +1:9
 -         _3 = const 4_i32;                // scope 0 at $DIR/ref_deref.rs:+1:8: +1:9
 -         _2 = &_3;                        // scope 0 at $DIR/ref_deref.rs:+1:6: +1:10
-+         _4 = const main::promoted[0];    // scope 0 at $DIR/ref_deref.rs:+1:6: +1:10
++         _4 = const _;                    // scope 0 at $DIR/ref_deref.rs:+1:6: +1:10
 +                                          // mir::Constant
 +                                          // + span: $DIR/ref_deref.rs:5:6: 5:10
 +                                          // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff b/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff
index 84ec5c8bb1db..ec3d90433159 100644
--- a/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff
+++ b/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff
@@ -11,7 +11,7 @@
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/ref_deref_project.rs:+1:5: +1:17
           StorageLive(_2);                 // scope 0 at $DIR/ref_deref_project.rs:+1:6: +1:17
-          _4 = const main::promoted[0];    // scope 0 at $DIR/ref_deref_project.rs:+1:6: +1:17
+          _4 = const _;                    // scope 0 at $DIR/ref_deref_project.rs:+1:6: +1:17
                                            // mir::Constant
                                            // + span: $DIR/ref_deref_project.rs:6:6: 6:17
                                            // + literal: Const { ty: &(i32, i32), val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/ref_deref_project.main.PromoteTemps.diff b/src/test/mir-opt/const_prop/ref_deref_project.main.PromoteTemps.diff
index 6f3a060a1260..cd0616e65baf 100644
--- a/src/test/mir-opt/const_prop/ref_deref_project.main.PromoteTemps.diff
+++ b/src/test/mir-opt/const_prop/ref_deref_project.main.PromoteTemps.diff
@@ -14,7 +14,7 @@
 -         StorageLive(_3);                 // scope 0 at $DIR/ref_deref_project.rs:+1:8: +1:14
 -         _3 = (const 4_i32, const 5_i32); // scope 0 at $DIR/ref_deref_project.rs:+1:8: +1:14
 -         _2 = &(_3.1: i32);               // scope 0 at $DIR/ref_deref_project.rs:+1:6: +1:17
-+         _4 = const main::promoted[0];    // scope 0 at $DIR/ref_deref_project.rs:+1:6: +1:17
++         _4 = const _;                    // scope 0 at $DIR/ref_deref_project.rs:+1:6: +1:17
 +                                          // mir::Constant
 +                                          // + span: $DIR/ref_deref_project.rs:6:6: 6:17
 +                                          // + literal: Const { ty: &(i32, i32), val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/slice_len.main.ConstProp.32bit.diff b/src/test/mir-opt/const_prop/slice_len.main.ConstProp.32bit.diff
index 0ebfbca21391..624376769b70 100644
--- a/src/test/mir-opt/const_prop/slice_len.main.ConstProp.32bit.diff
+++ b/src/test/mir-opt/const_prop/slice_len.main.ConstProp.32bit.diff
@@ -19,7 +19,7 @@
           StorageLive(_2);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:30
           StorageLive(_3);                 // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           StorageLive(_4);                 // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          _9 = const main::promoted[0];    // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
+          _9 = const _;                    // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
                                            // mir::Constant
                                            // + span: $DIR/slice_len.rs:5:6: 5:19
                                            // + literal: Const { ty: &[u32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/const_prop/slice_len.main.ConstProp.64bit.diff b/src/test/mir-opt/const_prop/slice_len.main.ConstProp.64bit.diff
index 0ebfbca21391..624376769b70 100644
--- a/src/test/mir-opt/const_prop/slice_len.main.ConstProp.64bit.diff
+++ b/src/test/mir-opt/const_prop/slice_len.main.ConstProp.64bit.diff
@@ -19,7 +19,7 @@
           StorageLive(_2);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:30
           StorageLive(_3);                 // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           StorageLive(_4);                 // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          _9 = const main::promoted[0];    // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
+          _9 = const _;                    // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
                                            // mir::Constant
                                            // + span: $DIR/slice_len.rs:5:6: 5:19
                                            // + literal: Const { ty: &[u32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff b/src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff
index 53f977de5d6a..995611f0e966 100644
--- a/src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff
+++ b/src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff
@@ -20,7 +20,7 @@
           _2 = core::str::<impl str>::as_bytes(move _3) -> bb1; // scope 0 at $DIR/deduplicate_blocks.rs:+1:11: +1:23
                                            // mir::Constant
                                            // + span: $DIR/deduplicate_blocks.rs:5:13: 5:21
-                                           // + literal: Const { ty: for<'r> fn(&'r str) -> &'r [u8] {core::str::<impl str>::as_bytes}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a str) -> &'a [u8] {core::str::<impl str>::as_bytes}, val: Value(<ZST>) }
       }
   
       bb1: {
diff --git a/src/test/mir-opt/derefer_complex_case.main.Derefer.diff b/src/test/mir-opt/derefer_complex_case.main.Derefer.diff
index 297836798cbc..713d56c38361 100644
--- a/src/test/mir-opt/derefer_complex_case.main.Derefer.diff
+++ b/src/test/mir-opt/derefer_complex_case.main.Derefer.diff
@@ -3,15 +3,15 @@
   
   fn main() -> () {
       let mut _0: ();                      // return place in scope 0 at $DIR/derefer_complex_case.rs:+0:11: +0:11
-      let mut _1: std::slice::Iter<i32>;   // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
+      let mut _1: std::slice::Iter<'_, i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
       let mut _2: &[i32; 2];               // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
       let _3: [i32; 2];                    // in scope 0 at $DIR/derefer_complex_case.rs:+1:18: +1:26
-      let mut _4: std::slice::Iter<i32>;   // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
+      let mut _4: std::slice::Iter<'_, i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
       let mut _5: ();                      // in scope 0 at $DIR/derefer_complex_case.rs:+0:1: +2:2
       let _6: ();                          // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
       let mut _7: std::option::Option<&i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
-      let mut _8: &mut std::slice::Iter<i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
-      let mut _9: &mut std::slice::Iter<i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
+      let mut _8: &mut std::slice::Iter<'_, i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
+      let mut _9: &mut std::slice::Iter<'_, i32>; // in scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
       let mut _10: isize;                  // in scope 0 at $DIR/derefer_complex_case.rs:+1:5: +1:40
       let mut _11: !;                      // in scope 0 at $DIR/derefer_complex_case.rs:+1:5: +1:40
       let mut _13: i32;                    // in scope 0 at $DIR/derefer_complex_case.rs:+1:34: +1:37
@@ -28,7 +28,7 @@
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
           StorageLive(_2);                 // scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
-          _14 = const main::promoted[0];   // scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
+          _14 = const _;                   // scope 0 at $DIR/derefer_complex_case.rs:+1:17: +1:26
                                            // mir::Constant
                                            // + span: $DIR/derefer_complex_case.rs:6:17: 6:26
                                            // + literal: Const { ty: &[i32; 2], val: Unevaluated(main, [], Some(promoted[0])) }
@@ -53,10 +53,10 @@
           StorageLive(_9);                 // scope 1 at $DIR/derefer_complex_case.rs:+1:17: +1:26
           _9 = &mut _4;                    // scope 1 at $DIR/derefer_complex_case.rs:+1:17: +1:26
           _8 = &mut (*_9);                 // scope 1 at $DIR/derefer_complex_case.rs:+1:17: +1:26
-          _7 = <std::slice::Iter<i32> as Iterator>::next(move _8) -> bb3; // scope 1 at $DIR/derefer_complex_case.rs:+1:17: +1:26
+          _7 = <std::slice::Iter<'_, i32> as Iterator>::next(move _8) -> bb3; // scope 1 at $DIR/derefer_complex_case.rs:+1:17: +1:26
                                            // mir::Constant
                                            // + span: $DIR/derefer_complex_case.rs:6:17: 6:26
-                                           // + literal: Const { ty: for<'r> fn(&'r mut std::slice::Iter<i32>) -> Option<<std::slice::Iter<i32> as Iterator>::Item> {<std::slice::Iter<i32> as Iterator>::next}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a mut std::slice::Iter<'_, i32>) -> Option<<std::slice::Iter<'_, i32> as Iterator>::Item> {<std::slice::Iter<'_, i32> as Iterator>::next}, val: Value(<ZST>) }
       }
   
       bb3: {
diff --git a/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
index a20a172af1bb..80b09ed5f8d3 100644
--- a/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
@@ -1,12 +1,12 @@
 - // MIR for `nrvo` before DestinationPropagation
 + // MIR for `nrvo` after DestinationPropagation
   
-  fn nrvo(_1: for<'r> fn(&'r mut [u8; 1024])) -> [u8; 1024] {
+  fn nrvo(_1: for<'a> fn(&'a mut [u8; 1024])) -> [u8; 1024] {
       debug init => _1;                    // in scope 0 at $DIR/simple.rs:+0:9: +0:13
       let mut _0: [u8; 1024];              // return place in scope 0 at $DIR/simple.rs:+0:39: +0:49
       let mut _2: [u8; 1024];              // in scope 0 at $DIR/simple.rs:+1:9: +1:16
       let _3: ();                          // in scope 0 at $DIR/simple.rs:+2:5: +2:19
-      let mut _4: for<'r> fn(&'r mut [u8; 1024]); // in scope 0 at $DIR/simple.rs:+2:5: +2:9
+      let mut _4: for<'a> fn(&'a mut [u8; 1024]); // in scope 0 at $DIR/simple.rs:+2:5: +2:9
       let mut _5: &mut [u8; 1024];         // in scope 0 at $DIR/simple.rs:+2:10: +2:18
       let mut _6: &mut [u8; 1024];         // in scope 0 at $DIR/simple.rs:+2:10: +2:18
       scope 1 {
diff --git a/src/test/mir-opt/dest-prop/union.rs b/src/test/mir-opt/dest-prop/union.rs
index 68c834dfbbf2..eb6cb09fc455 100644
--- a/src/test/mir-opt/dest-prop/union.rs
+++ b/src/test/mir-opt/dest-prop/union.rs
@@ -1,4 +1,4 @@
-//! Tests that we can propogate into places that are projections into unions
+//! Tests that we can propagate into places that are projections into unions
 // compile-flags: -Zunsound-mir-opts
 fn val() -> u32 {
     1
diff --git a/src/test/mir-opt/early_otherwise_branch_68867.rs b/src/test/mir-opt/early_otherwise_branch_68867.rs
index ca298e9211d4..a6a56f3a95d1 100644
--- a/src/test/mir-opt/early_otherwise_branch_68867.rs
+++ b/src/test/mir-opt/early_otherwise_branch_68867.rs
@@ -1,4 +1,6 @@
-// compile-flags: -Z mir-opt-level=4 -Zunsound-mir-opts
+// unit-test: EarlyOtherwiseBranch
+
+// FIXME: This test was broken by the derefer change.
 
 // example from #68867
 type CSSFloat = f32;
@@ -11,7 +13,6 @@ pub enum ViewportPercentageLength {
 }
 
 // EMIT_MIR early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
-// EMIT_MIR early_otherwise_branch_68867.try_sum EarlyOtherwiseBranch.before SimplifyConstCondition-final.after
 #[no_mangle]
 pub extern "C" fn try_sum(
     x: &ViewportPercentageLength,
diff --git a/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.before-SimplifyConstCondition-final.after.diff b/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.before-SimplifyConstCondition-final.after.diff
deleted file mode 100644
index 8b37fb79f411..000000000000
--- a/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.before-SimplifyConstCondition-final.after.diff
+++ /dev/null
@@ -1,322 +0,0 @@
-- // MIR for `try_sum` before EarlyOtherwiseBranch
-+ // MIR for `try_sum` after SimplifyConstCondition-final
-  
-  fn try_sum(_1: &ViewportPercentageLength, _2: &ViewportPercentageLength) -> Result<ViewportPercentageLength, ()> {
-      debug x => _1;                       // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+1:5: +1:6
-      debug other => _2;                   // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+2:5: +2:10
-      let mut _0: std::result::Result<ViewportPercentageLength, ()>; // return place in scope 0 at $DIR/early_otherwise_branch_68867.rs:+3:6: +3:42
-      let mut _3: ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +11:6
-      let mut _4: (&ViewportPercentageLength, &ViewportPercentageLength); // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _5: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:15: +5:16
-      let mut _6: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:18: +5:23
-      let mut _7: isize;                   // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:21: +6:30
-      let mut _8: isize;                   // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:21: +7:30
-      let mut _9: isize;                   // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:23: +8:34
-      let mut _10: isize;                  // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:23: +9:34
-      let mut _11: isize;                  // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:11: +6:18
-      let _12: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
-      let _13: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
-      let mut _14: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:49
-      let mut _15: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:41
-      let mut _16: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:44: +6:49
-      let _17: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
-      let _18: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
-      let mut _19: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:49
-      let mut _20: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:41
-      let mut _21: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:44: +7:49
-      let _22: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
-      let _23: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
-      let mut _24: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:55
-      let mut _25: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:47
-      let mut _26: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:50: +8:55
-      let _27: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
-      let _28: f32;                        // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
-      let mut _29: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:55
-      let mut _30: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:47
-      let mut _31: f32;                    // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:50: +9:55
-      let mut _32: !;                      // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:14: +10:28
-      let mut _33: ();                     // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:25: +10:27
-      let mut _34: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _35: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _36: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _37: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _38: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _39: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _40: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _41: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _42: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _43: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _44: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _45: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      let mut _46: &ViewportPercentageLength; // in scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-      scope 1 {
--         debug one => _12;                // in scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
--         debug other => _13;              // in scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
-+         debug one => _15;                // in scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
-+         debug other => _16;              // in scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
-      }
-      scope 2 {
--         debug one => _17;                // in scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
--         debug other => _18;              // in scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
-+         debug one => _20;                // in scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
-+         debug other => _21;              // in scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
-      }
-      scope 3 {
--         debug one => _22;                // in scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
--         debug other => _23;              // in scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
-+         debug one => _25;                // in scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
-+         debug other => _26;              // in scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
-      }
-      scope 4 {
--         debug one => _27;                // in scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
--         debug other => _28;              // in scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
-+         debug one => _30;                // in scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
-+         debug other => _31;              // in scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
-      }
-  
-      bb0: {
--         StorageLive(_3);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +11:6
--         StorageLive(_4);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
--         StorageLive(_5);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:15: +5:16
--         _5 = _1;                         // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:15: +5:16
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +11:6
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:15: +5:16
-+         (_4.0: &ViewportPercentageLength) = _1; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:15: +5:16
-          StorageLive(_6);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:18: +5:23
-          _6 = _2;                         // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:18: +5:23
-          Deinit(_4);                      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
--         (_4.0: &ViewportPercentageLength) = move _5; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          (_4.1: &ViewportPercentageLength) = move _6; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          StorageDead(_6);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:23: +5:24
--         StorageDead(_5);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:23: +5:24
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:23: +5:24
-          _34 = deref_copy (_4.0: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          _11 = discriminant((*_34));      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          switchInt(move _11) -> [0_isize: bb1, 1_isize: bb3, 2_isize: bb4, 3_isize: bb5, otherwise: bb11]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
-      }
-  
-      bb1: {
-          _35 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          _7 = discriminant((*_35));       // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          switchInt(move _7) -> [0_isize: bb6, otherwise: bb2]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
-      }
-  
-      bb2: {
-          StorageLive(_33);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:25: +10:27
-          nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:25: +10:27
-          Deinit(_0);                      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
-          nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
-          discriminant(_0) = 1;            // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
-          StorageDead(_33);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:27: +10:28
--         StorageDead(_3);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+11:6: +11:7
--         StorageDead(_4);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:1: +12:2
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+11:6: +11:7
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:1: +12:2
-          return;                          // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
-      }
-  
-      bb3: {
-          _36 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          _8 = discriminant((*_36));       // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          switchInt(move _8) -> [1_isize: bb7, otherwise: bb2]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
-      }
-  
-      bb4: {
-          _37 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          _9 = discriminant((*_37));       // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          switchInt(move _9) -> [2_isize: bb8, otherwise: bb2]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
-      }
-  
-      bb5: {
-          _38 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          _10 = discriminant((*_38));      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          switchInt(move _10) -> [3_isize: bb9, otherwise: bb2]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
-      }
-  
-      bb6: {
--         StorageLive(_12);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
-          _39 = deref_copy (_4.0: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
--         _12 = (((*_39) as Vw).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
--         StorageLive(_13);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
-+         _15 = (((*_39) as Vw).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:14: +6:17
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
-          _40 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
--         _13 = (((*_40) as Vw).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
--         StorageLive(_14);                // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:49
--         StorageLive(_15);                // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:41
--         _15 = _12;                       // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:41
--         StorageLive(_16);                // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:44: +6:49
--         _16 = _13;                       // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:44: +6:49
--         _14 = Add(move _15, move _16);   // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:49
--         StorageDead(_16);                // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:48: +6:49
--         StorageDead(_15);                // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:48: +6:49
--         Deinit(_3);                      // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:35: +6:50
--         ((_3 as Vw).0: f32) = move _14;  // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:35: +6:50
--         discriminant(_3) = 0;            // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:35: +6:50
--         StorageDead(_14);                // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
--         StorageDead(_13);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
--         StorageDead(_12);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
-+         _16 = (((*_40) as Vw).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:24: +6:29
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:49
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:41
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:41
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:44: +6:49
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:44: +6:49
-+         ((((_0 as Ok).0: ViewportPercentageLength) as Vw).0: f32) = Add(move _15, move _16); // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:38: +6:49
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:48: +6:49
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:48: +6:49
-+         Deinit(((_0 as Ok).0: ViewportPercentageLength)); // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:35: +6:50
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:35: +6:50
-+         discriminant(((_0 as Ok).0: ViewportPercentageLength)) = 0; // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:35: +6:50
-+         nop;                             // scope 1 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
-          goto -> bb10;                    // scope 0 at $DIR/early_otherwise_branch_68867.rs:+6:49: +6:50
-      }
-  
-      bb7: {
--         StorageLive(_17);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
-          _41 = deref_copy (_4.0: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
--         _17 = (((*_41) as Vh).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
--         StorageLive(_18);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
-+         _20 = (((*_41) as Vh).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:14: +7:17
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
-          _42 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
--         _18 = (((*_42) as Vh).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
--         StorageLive(_19);                // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:49
--         StorageLive(_20);                // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:41
--         _20 = _17;                       // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:41
--         StorageLive(_21);                // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:44: +7:49
--         _21 = _18;                       // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:44: +7:49
--         _19 = Add(move _20, move _21);   // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:49
--         StorageDead(_21);                // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:48: +7:49
--         StorageDead(_20);                // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:48: +7:49
--         Deinit(_3);                      // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:35: +7:50
--         ((_3 as Vh).0: f32) = move _19;  // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:35: +7:50
--         discriminant(_3) = 1;            // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:35: +7:50
--         StorageDead(_19);                // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
--         StorageDead(_18);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
--         StorageDead(_17);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
-+         _21 = (((*_42) as Vh).0: f32);   // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:24: +7:29
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:49
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:41
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:41
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:44: +7:49
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:44: +7:49
-+         ((((_0 as Ok).0: ViewportPercentageLength) as Vh).0: f32) = Add(move _20, move _21); // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:38: +7:49
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:48: +7:49
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:48: +7:49
-+         Deinit(((_0 as Ok).0: ViewportPercentageLength)); // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:35: +7:50
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:35: +7:50
-+         discriminant(((_0 as Ok).0: ViewportPercentageLength)) = 1; // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:35: +7:50
-+         nop;                             // scope 2 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
-          goto -> bb10;                    // scope 0 at $DIR/early_otherwise_branch_68867.rs:+7:49: +7:50
-      }
-  
-      bb8: {
--         StorageLive(_22);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
-          _43 = deref_copy (_4.0: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
--         _22 = (((*_43) as Vmin).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
--         StorageLive(_23);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
-+         _25 = (((*_43) as Vmin).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:16: +8:19
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
-          _44 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
--         _23 = (((*_44) as Vmin).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
--         StorageLive(_24);                // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:55
--         StorageLive(_25);                // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:47
--         _25 = _22;                       // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:47
--         StorageLive(_26);                // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:50: +8:55
--         _26 = _23;                       // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:50: +8:55
--         _24 = Add(move _25, move _26);   // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:55
--         StorageDead(_26);                // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:54: +8:55
--         StorageDead(_25);                // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:54: +8:55
--         Deinit(_3);                      // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:39: +8:56
--         ((_3 as Vmin).0: f32) = move _24; // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:39: +8:56
--         discriminant(_3) = 2;            // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:39: +8:56
--         StorageDead(_24);                // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
--         StorageDead(_23);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
--         StorageDead(_22);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
-+         _26 = (((*_44) as Vmin).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:28: +8:33
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:55
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:47
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:47
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:50: +8:55
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:50: +8:55
-+         ((((_0 as Ok).0: ViewportPercentageLength) as Vmin).0: f32) = Add(move _25, move _26); // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:44: +8:55
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:54: +8:55
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:54: +8:55
-+         Deinit(((_0 as Ok).0: ViewportPercentageLength)); // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:39: +8:56
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:39: +8:56
-+         discriminant(((_0 as Ok).0: ViewportPercentageLength)) = 2; // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:39: +8:56
-+         nop;                             // scope 3 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
-          goto -> bb10;                    // scope 0 at $DIR/early_otherwise_branch_68867.rs:+8:55: +8:56
-      }
-  
-      bb9: {
--         StorageLive(_27);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
-          _45 = deref_copy (_4.0: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
--         _27 = (((*_45) as Vmax).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
--         StorageLive(_28);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
-+         _30 = (((*_45) as Vmax).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:16: +9:19
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
-          _46 = deref_copy (_4.1: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
--         _28 = (((*_46) as Vmax).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
--         StorageLive(_29);                // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:55
--         StorageLive(_30);                // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:47
--         _30 = _27;                       // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:47
--         StorageLive(_31);                // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:50: +9:55
--         _31 = _28;                       // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:50: +9:55
--         _29 = Add(move _30, move _31);   // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:55
--         StorageDead(_31);                // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:54: +9:55
--         StorageDead(_30);                // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:54: +9:55
--         Deinit(_3);                      // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:39: +9:56
--         ((_3 as Vmax).0: f32) = move _29; // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:39: +9:56
--         discriminant(_3) = 3;            // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:39: +9:56
--         StorageDead(_29);                // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
--         StorageDead(_28);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
--         StorageDead(_27);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
-+         _31 = (((*_46) as Vmax).0: f32); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:28: +9:33
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:55
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:47
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:47
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:50: +9:55
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:50: +9:55
-+         ((((_0 as Ok).0: ViewportPercentageLength) as Vmax).0: f32) = Add(move _30, move _31); // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:44: +9:55
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:54: +9:55
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:54: +9:55
-+         Deinit(((_0 as Ok).0: ViewportPercentageLength)); // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:39: +9:56
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:39: +9:56
-+         discriminant(((_0 as Ok).0: ViewportPercentageLength)) = 3; // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:39: +9:56
-+         nop;                             // scope 4 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
-          goto -> bb10;                    // scope 0 at $DIR/early_otherwise_branch_68867.rs:+9:55: +9:56
-      }
-  
-      bb10: {
-          Deinit(_0);                      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:5: +11:7
--         ((_0 as Ok).0: ViewportPercentageLength) = move _3; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:5: +11:7
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:5: +11:7
-          discriminant(_0) = 0;            // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:5: +11:7
--         StorageDead(_3);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+11:6: +11:7
--         StorageDead(_4);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:1: +12:2
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+11:6: +11:7
-+         nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:1: +12:2
-          return;                          // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
-      }
-  
-      bb11: {
-          unreachable;                     // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff b/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
index 50a58d4792a8..6bc025bb5b20 100644
--- a/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
+++ b/src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
@@ -80,7 +80,7 @@
           StorageDead(_5);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:23: +5:24
           _34 = deref_copy (_4.0: &ViewportPercentageLength); // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
           _11 = discriminant((*_34));      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:14: +5:24
-          switchInt(move _11) -> [0_isize: bb1, 1_isize: bb3, 2_isize: bb4, 3_isize: bb5, otherwise: bb11]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
+          switchInt(move _11) -> [0_isize: bb1, 1_isize: bb3, 2_isize: bb4, 3_isize: bb5, otherwise: bb2]; // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:8: +5:24
       }
   
       bb1: {
@@ -91,14 +91,14 @@
   
       bb2: {
           StorageLive(_33);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:25: +10:27
-          nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:25: +10:27
+          Deinit(_33);                     // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:25: +10:27
           Deinit(_0);                      // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
-          nop;                             // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
+          ((_0 as Err).0: ()) = move _33;  // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
           discriminant(_0) = 1;            // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:21: +10:28
           StorageDead(_33);                // scope 0 at $DIR/early_otherwise_branch_68867.rs:+10:27: +10:28
           StorageDead(_3);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+11:6: +11:7
           StorageDead(_4);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:1: +12:2
-          return;                          // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
+          goto -> bb11;                    // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
       }
   
       bb3: {
@@ -221,11 +221,11 @@
           discriminant(_0) = 0;            // scope 0 at $DIR/early_otherwise_branch_68867.rs:+5:5: +11:7
           StorageDead(_3);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+11:6: +11:7
           StorageDead(_4);                 // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:1: +12:2
-          return;                          // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
+          goto -> bb11;                    // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
       }
   
       bb11: {
-          unreachable;                     // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
+          return;                          // scope 0 at $DIR/early_otherwise_branch_68867.rs:+12:2: +12:2
       }
   }
   
diff --git a/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff b/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
index 9e089b01b0f3..659aed18f043 100644
--- a/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
+++ b/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
@@ -1,12 +1,12 @@
 - // MIR for `no_downcast` before EarlyOtherwiseBranch
 + // MIR for `no_downcast` after EarlyOtherwiseBranch
   
-  fn no_downcast(_1: &E) -> u32 {
+  fn no_downcast(_1: &E<'_>) -> u32 {
       debug e => _1;                       // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:+0:16: +0:17
       let mut _0: u32;                     // return place in scope 0 at $DIR/early_otherwise_branch_soundness.rs:+0:26: +0:29
       let mut _2: isize;                   // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:+1:20: +1:30
       let mut _3: isize;                   // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:+1:12: +1:31
-      let mut _4: &E;                      // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:+0:16: +0:17
+      let mut _4: &E<'_>;                  // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:+0:16: +0:17
       scope 1 {
       }
   
@@ -16,7 +16,7 @@
       }
   
       bb1: {
-          _4 = deref_copy (((*_1) as Some).0: &E); // scope 1 at $DIR/early_otherwise_branch_soundness.rs:+1:12: +1:31
+          _4 = deref_copy (((*_1) as Some).0: &E<'_>); // scope 1 at $DIR/early_otherwise_branch_soundness.rs:+1:12: +1:31
           _2 = discriminant((*_4));        // scope 1 at $DIR/early_otherwise_branch_soundness.rs:+1:12: +1:31
           switchInt(move _2) -> [1_isize: bb2, otherwise: bb3]; // scope 1 at $DIR/early_otherwise_branch_soundness.rs:+1:12: +1:31
       }
diff --git a/src/test/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir b/src/test/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
index d39145973624..96716a39a2bf 100644
--- a/src/test/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
+++ b/src/test/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
@@ -8,13 +8,13 @@ fn match_tuple(_1: (u32, bool, Option<i32>, u32)) -> u32 {
     let mut _4: bool;                    // in scope 0 at $DIR/exponential-or.rs:+2:70: +2:77
     let mut _5: bool;                    // in scope 0 at $DIR/exponential-or.rs:+2:62: +2:67
     let mut _6: bool;                    // in scope 0 at $DIR/exponential-or.rs:+2:62: +2:67
-    let _7: u32;                         // in scope 0 at $DIR/exponential-or.rs:+2:10: +2:21
-    let _8: u32;                         // in scope 0 at $DIR/exponential-or.rs:+2:57: +2:78
+    let _7: u32;                         // in scope 0 at $DIR/exponential-or.rs:+2:10: +2:11
+    let _8: u32;                         // in scope 0 at $DIR/exponential-or.rs:+2:57: +2:58
     let mut _9: u32;                     // in scope 0 at $DIR/exponential-or.rs:+2:83: +2:84
     let mut _10: u32;                    // in scope 0 at $DIR/exponential-or.rs:+2:87: +2:88
     scope 1 {
-        debug y => _7;                   // in scope 1 at $DIR/exponential-or.rs:+2:10: +2:21
-        debug z => _8;                   // in scope 1 at $DIR/exponential-or.rs:+2:57: +2:78
+        debug y => _7;                   // in scope 1 at $DIR/exponential-or.rs:+2:10: +2:11
+        debug z => _8;                   // in scope 1 at $DIR/exponential-or.rs:+2:57: +2:58
     }
 
     bb0: {
@@ -61,10 +61,10 @@ fn match_tuple(_1: (u32, bool, Option<i32>, u32)) -> u32 {
     }
 
     bb9: {
-        StorageLive(_7);                 // scope 0 at $DIR/exponential-or.rs:+2:10: +2:21
-        _7 = (_1.0: u32);                // scope 0 at $DIR/exponential-or.rs:+2:10: +2:21
-        StorageLive(_8);                 // scope 0 at $DIR/exponential-or.rs:+2:57: +2:78
-        _8 = (_1.3: u32);                // scope 0 at $DIR/exponential-or.rs:+2:57: +2:78
+        StorageLive(_7);                 // scope 0 at $DIR/exponential-or.rs:+2:10: +2:11
+        _7 = (_1.0: u32);                // scope 0 at $DIR/exponential-or.rs:+2:10: +2:11
+        StorageLive(_8);                 // scope 0 at $DIR/exponential-or.rs:+2:57: +2:58
+        _8 = (_1.3: u32);                // scope 0 at $DIR/exponential-or.rs:+2:57: +2:58
         StorageLive(_9);                 // scope 1 at $DIR/exponential-or.rs:+2:83: +2:84
         _9 = _7;                         // scope 1 at $DIR/exponential-or.rs:+2:83: +2:84
         StorageLive(_10);                // scope 1 at $DIR/exponential-or.rs:+2:87: +2:88
diff --git a/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff b/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
index dca36b1a76d0..e83a358b7258 100644
--- a/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
+++ b/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
@@ -1,24 +1,24 @@
 - // MIR for `float_to_exponential_common` before ConstProp
 + // MIR for `float_to_exponential_common` after ConstProp
   
-  fn float_to_exponential_common(_1: &mut Formatter, _2: &T, _3: bool) -> Result<(), std::fmt::Error> {
+  fn float_to_exponential_common(_1: &mut Formatter<'_>, _2: &T, _3: bool) -> Result<(), std::fmt::Error> {
       debug fmt => _1;                     // in scope 0 at $DIR/funky_arms.rs:+0:35: +0:38
       debug num => _2;                     // in scope 0 at $DIR/funky_arms.rs:+0:60: +0:63
       debug upper => _3;                   // in scope 0 at $DIR/funky_arms.rs:+0:69: +0:74
       let mut _0: std::result::Result<(), std::fmt::Error>; // return place in scope 0 at $DIR/funky_arms.rs:+0:85: +0:91
       let _4: bool;                        // in scope 0 at $DIR/funky_arms.rs:+4:9: +4:19
-      let mut _5: &std::fmt::Formatter;    // in scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
+      let mut _5: &std::fmt::Formatter<'_>; // in scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
       let mut _7: std::option::Option<usize>; // in scope 0 at $DIR/funky_arms.rs:+13:30: +13:45
-      let mut _8: &std::fmt::Formatter;    // in scope 0 at $DIR/funky_arms.rs:+13:30: +13:45
+      let mut _8: &std::fmt::Formatter<'_>; // in scope 0 at $DIR/funky_arms.rs:+13:30: +13:45
       let mut _9: isize;                   // in scope 0 at $DIR/funky_arms.rs:+13:12: +13:27
-      let mut _11: &mut std::fmt::Formatter; // in scope 0 at $DIR/funky_arms.rs:+15:43: +15:46
+      let mut _11: &mut std::fmt::Formatter<'_>; // in scope 0 at $DIR/funky_arms.rs:+15:43: +15:46
       let mut _12: &T;                     // in scope 0 at $DIR/funky_arms.rs:+15:48: +15:51
       let mut _13: core::num::flt2dec::Sign; // in scope 0 at $DIR/funky_arms.rs:+15:53: +15:57
       let mut _14: u32;                    // in scope 0 at $DIR/funky_arms.rs:+15:59: +15:79
       let mut _15: u32;                    // in scope 0 at $DIR/funky_arms.rs:+15:59: +15:75
       let mut _16: usize;                  // in scope 0 at $DIR/funky_arms.rs:+15:59: +15:68
       let mut _17: bool;                   // in scope 0 at $DIR/funky_arms.rs:+15:81: +15:86
-      let mut _18: &mut std::fmt::Formatter; // in scope 0 at $DIR/funky_arms.rs:+17:46: +17:49
+      let mut _18: &mut std::fmt::Formatter<'_>; // in scope 0 at $DIR/funky_arms.rs:+17:46: +17:49
       let mut _19: &T;                     // in scope 0 at $DIR/funky_arms.rs:+17:51: +17:54
       let mut _20: core::num::flt2dec::Sign; // in scope 0 at $DIR/funky_arms.rs:+17:56: +17:60
       let mut _21: bool;                   // in scope 0 at $DIR/funky_arms.rs:+17:62: +17:67
@@ -38,10 +38,10 @@
           StorageLive(_4);                 // scope 0 at $DIR/funky_arms.rs:+4:9: +4:19
           StorageLive(_5);                 // scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
           _5 = &(*_1);                     // scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
-          _4 = Formatter::sign_plus(move _5) -> bb1; // scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
+          _4 = Formatter::<'_>::sign_plus(move _5) -> bb1; // scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
                                            // mir::Constant
                                            // + span: $DIR/funky_arms.rs:15:26: 15:35
-                                           // + literal: Const { ty: for<'r> fn(&'r Formatter) -> bool {Formatter::sign_plus}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a Formatter<'_>) -> bool {Formatter::<'_>::sign_plus}, val: Value(<ZST>) }
       }
   
       bb1: {
@@ -66,10 +66,10 @@
           StorageLive(_7);                 // scope 3 at $DIR/funky_arms.rs:+13:30: +13:45
           StorageLive(_8);                 // scope 3 at $DIR/funky_arms.rs:+13:30: +13:45
           _8 = &(*_1);                     // scope 3 at $DIR/funky_arms.rs:+13:30: +13:45
-          _7 = Formatter::precision(move _8) -> bb5; // scope 3 at $DIR/funky_arms.rs:+13:30: +13:45
+          _7 = Formatter::<'_>::precision(move _8) -> bb5; // scope 3 at $DIR/funky_arms.rs:+13:30: +13:45
                                            // mir::Constant
                                            // + span: $DIR/funky_arms.rs:24:34: 24:43
-                                           // + literal: Const { ty: for<'r> fn(&'r Formatter) -> Option<usize> {Formatter::precision}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a Formatter<'_>) -> Option<usize> {Formatter::<'_>::precision}, val: Value(<ZST>) }
       }
   
       bb5: {
@@ -100,7 +100,7 @@
           _0 = float_to_exponential_common_exact::<T>(move _11, move _12, move _13, move _14, move _17) -> bb7; // scope 3 at $DIR/funky_arms.rs:+15:9: +15:87
                                            // mir::Constant
                                            // + span: $DIR/funky_arms.rs:26:9: 26:42
-                                           // + literal: Const { ty: for<'r, 's, 't0> fn(&'r mut Formatter<'s>, &'t0 T, Sign, u32, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_exact::<T>}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a, 'b, 'c> fn(&'a mut Formatter<'b>, &'c T, Sign, u32, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_exact::<T>}, val: Value(<ZST>) }
       }
   
       bb7: {
@@ -125,7 +125,7 @@
           _0 = float_to_exponential_common_shortest::<T>(move _18, move _19, move _20, move _21) -> bb9; // scope 2 at $DIR/funky_arms.rs:+17:9: +17:68
                                            // mir::Constant
                                            // + span: $DIR/funky_arms.rs:28:9: 28:45
-                                           // + literal: Const { ty: for<'r, 's, 't0> fn(&'r mut Formatter<'s>, &'t0 T, Sign, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_shortest::<T>}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a, 'b, 'c> fn(&'a mut Formatter<'b>, &'c T, Sign, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_shortest::<T>}, val: Value(<ZST>) }
       }
   
       bb9: {
diff --git a/src/test/mir-opt/generator_drop_cleanup.main-{closure#0}.generator_drop.0.mir b/src/test/mir-opt/generator_drop_cleanup.main-{closure#0}.generator_drop.0.mir
index 0d10f9b5ffb4..c718138b6b37 100644
--- a/src/test/mir-opt/generator_drop_cleanup.main-{closure#0}.generator_drop.0.mir
+++ b/src/test/mir-opt/generator_drop_cleanup.main-{closure#0}.generator_drop.0.mir
@@ -15,70 +15,70 @@
 } */
 
 fn main::{closure#0}(_1: *mut [generator@$DIR/generator-drop-cleanup.rs:10:15: 10:17]) -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
-    let mut _2: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
-    let _3: std::string::String;         // in scope 0 at $DIR/generator-drop-cleanup.rs:11:13: 11:15
-    let _4: ();                          // in scope 0 at $DIR/generator-drop-cleanup.rs:12:9: 12:14
-    let mut _5: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:12:9: 12:14
-    let mut _6: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:10:18: 10:18
-    let mut _7: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
-    let mut _8: u32;                     // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+    let mut _0: ();                      // return place in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
+    let mut _2: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
+    let _3: std::string::String;         // in scope 0 at $DIR/generator-drop-cleanup.rs:+1:13: +1:15
+    let _4: ();                          // in scope 0 at $DIR/generator-drop-cleanup.rs:+2:9: +2:14
+    let mut _5: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:+2:9: +2:14
+    let mut _6: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:18: +0:18
+    let mut _7: ();                      // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
+    let mut _8: u32;                     // in scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     scope 1 {
-        debug _s => (((*_1) as variant#3).0: std::string::String); // in scope 1 at $DIR/generator-drop-cleanup.rs:11:13: 11:15
+        debug _s => (((*_1) as variant#3).0: std::string::String); // in scope 1 at $DIR/generator-drop-cleanup.rs:+1:13: +1:15
     }
 
     bb0: {
-        _8 = discriminant((*_1));        // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
-        switchInt(move _8) -> [0_u32: bb7, 3_u32: bb10, otherwise: bb11]; // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        _8 = discriminant((*_1));        // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
+        switchInt(move _8) -> [0_u32: bb7, 3_u32: bb10, otherwise: bb11]; // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb1: {
-        StorageDead(_5);                 // scope 1 at $DIR/generator-drop-cleanup.rs:12:13: 12:14
-        StorageDead(_4);                 // scope 1 at $DIR/generator-drop-cleanup.rs:12:14: 12:15
-        drop((((*_1) as variant#3).0: std::string::String)) -> [return: bb2, unwind: bb5]; // scope 0 at $DIR/generator-drop-cleanup.rs:13:5: 13:6
+        StorageDead(_5);                 // scope 1 at $DIR/generator-drop-cleanup.rs:+2:13: +2:14
+        StorageDead(_4);                 // scope 1 at $DIR/generator-drop-cleanup.rs:+2:14: +2:15
+        drop((((*_1) as variant#3).0: std::string::String)) -> [return: bb2, unwind: bb5]; // scope 0 at $DIR/generator-drop-cleanup.rs:+3:5: +3:6
     }
 
     bb2: {
-        nop;                             // scope 0 at $DIR/generator-drop-cleanup.rs:13:5: 13:6
-        goto -> bb8;                     // scope 0 at $DIR/generator-drop-cleanup.rs:13:5: 13:6
+        nop;                             // scope 0 at $DIR/generator-drop-cleanup.rs:+3:5: +3:6
+        goto -> bb8;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+3:5: +3:6
     }
 
     bb3: {
-        return;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        return;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb4 (cleanup): {
-        resume;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        resume;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb5 (cleanup): {
-        nop;                             // scope 0 at $DIR/generator-drop-cleanup.rs:13:5: 13:6
-        goto -> bb4;                     // scope 0 at $DIR/generator-drop-cleanup.rs:13:5: 13:6
+        nop;                             // scope 0 at $DIR/generator-drop-cleanup.rs:+3:5: +3:6
+        goto -> bb4;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+3:5: +3:6
     }
 
     bb6: {
-        return;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        return;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb7: {
-        goto -> bb9;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        goto -> bb9;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb8: {
-        goto -> bb3;                     // scope 0 at $DIR/generator-drop-cleanup.rs:13:5: 13:6
+        goto -> bb3;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+3:5: +3:6
     }
 
     bb9: {
-        goto -> bb6;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        goto -> bb6;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb10: {
-        StorageLive(_4);                 // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
-        StorageLive(_5);                 // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
-        goto -> bb1;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        StorageLive(_4);                 // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
+        StorageLive(_5);                 // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
+        goto -> bb1;                     // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 
     bb11: {
-        return;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +0:17
+        return;                          // scope 0 at $DIR/generator-drop-cleanup.rs:+0:15: +3:6
     }
 }
diff --git a/src/test/mir-opt/generator_storage_dead_unwind.main-{closure#0}.StateTransform.before.mir b/src/test/mir-opt/generator_storage_dead_unwind.main-{closure#0}.StateTransform.before.mir
index 94f4a5a63178..3184343f207b 100644
--- a/src/test/mir-opt/generator_storage_dead_unwind.main-{closure#0}.StateTransform.before.mir
+++ b/src/test/mir-opt/generator_storage_dead_unwind.main-{closure#0}.StateTransform.before.mir
@@ -3,122 +3,122 @@
 fn main::{closure#0}(_1: [generator@$DIR/generator-storage-dead-unwind.rs:22:16: 22:18], _2: ()) -> ()
 yields ()
  {
-    let mut _0: ();                      // return place in scope 0 at $DIR/generator-storage-dead-unwind.rs:22:19: 22:19
-    let _3: Foo;                         // in scope 0 at $DIR/generator-storage-dead-unwind.rs:23:13: 23:14
-    let _5: ();                          // in scope 0 at $DIR/generator-storage-dead-unwind.rs:25:9: 25:14
-    let mut _6: ();                      // in scope 0 at $DIR/generator-storage-dead-unwind.rs:25:9: 25:14
-    let _7: ();                          // in scope 0 at $DIR/generator-storage-dead-unwind.rs:26:9: 26:16
-    let mut _8: Foo;                     // in scope 0 at $DIR/generator-storage-dead-unwind.rs:26:14: 26:15
-    let _9: ();                          // in scope 0 at $DIR/generator-storage-dead-unwind.rs:27:9: 27:16
-    let mut _10: Bar;                    // in scope 0 at $DIR/generator-storage-dead-unwind.rs:27:14: 27:15
+    let mut _0: ();                      // return place in scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:19: +0:19
+    let _3: Foo;                         // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+1:13: +1:14
+    let _5: ();                          // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+3:9: +3:14
+    let mut _6: ();                      // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+3:9: +3:14
+    let _7: ();                          // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+4:9: +4:16
+    let mut _8: Foo;                     // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+4:14: +4:15
+    let _9: ();                          // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+5:9: +5:16
+    let mut _10: Bar;                    // in scope 0 at $DIR/generator-storage-dead-unwind.rs:+5:14: +5:15
     scope 1 {
-        debug a => _3;                   // in scope 1 at $DIR/generator-storage-dead-unwind.rs:23:13: 23:14
-        let _4: Bar;                     // in scope 1 at $DIR/generator-storage-dead-unwind.rs:24:13: 24:14
+        debug a => _3;                   // in scope 1 at $DIR/generator-storage-dead-unwind.rs:+1:13: +1:14
+        let _4: Bar;                     // in scope 1 at $DIR/generator-storage-dead-unwind.rs:+2:13: +2:14
         scope 2 {
-            debug b => _4;               // in scope 2 at $DIR/generator-storage-dead-unwind.rs:24:13: 24:14
+            debug b => _4;               // in scope 2 at $DIR/generator-storage-dead-unwind.rs:+2:13: +2:14
         }
     }
 
     bb0: {
-        StorageLive(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:23:13: 23:14
-        _3 = Foo(const 5_i32);           // scope 0 at $DIR/generator-storage-dead-unwind.rs:23:17: 23:23
-        StorageLive(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:24:13: 24:14
-        _4 = Bar(const 6_i32);           // scope 1 at $DIR/generator-storage-dead-unwind.rs:24:17: 24:23
-        StorageLive(_5);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:9: 25:14
-        StorageLive(_6);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:9: 25:14
-        _6 = ();                         // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:9: 25:14
-        _5 = yield(move _6) -> [resume: bb1, drop: bb6]; // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:9: 25:14
+        StorageLive(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:+1:13: +1:14
+        _3 = Foo(const 5_i32);           // scope 0 at $DIR/generator-storage-dead-unwind.rs:+1:17: +1:23
+        StorageLive(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:+2:13: +2:14
+        _4 = Bar(const 6_i32);           // scope 1 at $DIR/generator-storage-dead-unwind.rs:+2:17: +2:23
+        StorageLive(_5);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:9: +3:14
+        StorageLive(_6);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:9: +3:14
+        _6 = ();                         // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:9: +3:14
+        _5 = yield(move _6) -> [resume: bb1, drop: bb6]; // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:9: +3:14
     }
 
     bb1: {
-        StorageDead(_6);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:13: 25:14
-        StorageDead(_5);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:14: 25:15
-        StorageLive(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:9: 26:16
-        StorageLive(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:14: 26:15
-        _8 = move _3;                    // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:14: 26:15
-        _7 = take::<Foo>(move _8) -> [return: bb2, unwind: bb10]; // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:9: 26:16
+        StorageDead(_6);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:13: +3:14
+        StorageDead(_5);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:14: +3:15
+        StorageLive(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:9: +4:16
+        StorageLive(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:14: +4:15
+        _8 = move _3;                    // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:14: +4:15
+        _7 = take::<Foo>(move _8) -> [return: bb2, unwind: bb10]; // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:9: +4:16
                                          // mir::Constant
                                          // + span: $DIR/generator-storage-dead-unwind.rs:26:9: 26:13
                                          // + literal: Const { ty: fn(Foo) {take::<Foo>}, val: Value(<ZST>) }
     }
 
     bb2: {
-        StorageDead(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:15: 26:16
-        StorageDead(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:16: 26:17
-        StorageLive(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:9: 27:16
-        StorageLive(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:14: 27:15
-        _10 = move _4;                   // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:14: 27:15
-        _9 = take::<Bar>(move _10) -> [return: bb3, unwind: bb9]; // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:9: 27:16
+        StorageDead(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:15: +4:16
+        StorageDead(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:16: +4:17
+        StorageLive(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:9: +5:16
+        StorageLive(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:14: +5:15
+        _10 = move _4;                   // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:14: +5:15
+        _9 = take::<Bar>(move _10) -> [return: bb3, unwind: bb9]; // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:9: +5:16
                                          // mir::Constant
                                          // + span: $DIR/generator-storage-dead-unwind.rs:27:9: 27:13
                                          // + literal: Const { ty: fn(Bar) {take::<Bar>}, val: Value(<ZST>) }
     }
 
     bb3: {
-        StorageDead(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:15: 27:16
-        StorageDead(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:16: 27:17
-        _0 = const ();                   // scope 0 at $DIR/generator-storage-dead-unwind.rs:22:19: 28:6
-        StorageDead(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        goto -> bb4;                     // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:15: +5:16
+        StorageDead(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:16: +5:17
+        _0 = const ();                   // scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:19: +6:6
+        StorageDead(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        goto -> bb4;                     // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 
     bb4: {
-        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        drop(_1) -> [return: bb5, unwind: bb14]; // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        drop(_1) -> [return: bb5, unwind: bb14]; // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 
     bb5: {
-        return;                          // scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:18: +0:18
+        return;                          // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:6: +6:6
     }
 
     bb6: {
-        StorageDead(_6);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:13: 25:14
-        StorageDead(_5);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:25:14: 25:15
-        StorageDead(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        drop(_3) -> [return: bb7, unwind: bb15]; // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_6);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:13: +3:14
+        StorageDead(_5);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+3:14: +3:15
+        StorageDead(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        drop(_3) -> [return: bb7, unwind: bb15]; // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 
     bb7: {
-        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        drop(_1) -> [return: bb8, unwind: bb14]; // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        drop(_1) -> [return: bb8, unwind: bb14]; // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 
     bb8: {
-        generator_drop;                  // scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:16: +0:18
+        generator_drop;                  // scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:16: +6:6
     }
 
     bb9 (cleanup): {
-        StorageDead(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:15: 27:16
-        StorageDead(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:27:16: 27:17
+        StorageDead(_10);                // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:15: +5:16
+        StorageDead(_9);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+5:16: +5:17
         goto -> bb12;                    // scope 2 at no-location
     }
 
     bb10 (cleanup): {
-        goto -> bb11;                    // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:15: 26:16
+        goto -> bb11;                    // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:15: +4:16
     }
 
     bb11 (cleanup): {
-        StorageDead(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:15: 26:16
-        StorageDead(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:26:16: 26:17
+        StorageDead(_8);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:15: +4:16
+        StorageDead(_7);                 // scope 2 at $DIR/generator-storage-dead-unwind.rs:+4:16: +4:17
         goto -> bb12;                    // scope 2 at no-location
     }
 
     bb12 (cleanup): {
-        StorageDead(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        goto -> bb13;                    // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_4);                 // scope 1 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        goto -> bb13;                    // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 
     bb13 (cleanup): {
-        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        drop(_1) -> bb14;                // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        drop(_1) -> bb14;                // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 
     bb14 (cleanup): {
-        resume;                          // scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:16: +0:18
+        resume;                          // scope 0 at $DIR/generator-storage-dead-unwind.rs:+0:16: +6:6
     }
 
     bb15 (cleanup): {
-        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
-        drop(_1) -> bb14;                // scope 0 at $DIR/generator-storage-dead-unwind.rs:28:5: 28:6
+        StorageDead(_3);                 // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
+        drop(_1) -> bb14;                // scope 0 at $DIR/generator-storage-dead-unwind.rs:+6:5: +6:6
     }
 }
diff --git a/src/test/mir-opt/generator_tiny.main-{closure#0}.generator_resume.0.mir b/src/test/mir-opt/generator_tiny.main-{closure#0}.generator_resume.0.mir
index 927f10242d2f..07aeeaae012c 100644
--- a/src/test/mir-opt/generator_tiny.main-{closure#0}.generator_resume.0.mir
+++ b/src/test/mir-opt/generator_tiny.main-{closure#0}.generator_resume.0.mir
@@ -16,69 +16,69 @@
 
 fn main::{closure#0}(_1: Pin<&mut [generator@$DIR/generator-tiny.rs:19:16: 19:24]>, _2: u8) -> GeneratorState<(), ()> {
     debug _x => _10;                     // in scope 0 at $DIR/generator-tiny.rs:+0:17: +0:19
-    let mut _0: std::ops::GeneratorState<(), ()>; // return place in scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-    let _3: HasDrop;                     // in scope 0 at $DIR/generator-tiny.rs:20:13: 20:15
-    let mut _4: !;                       // in scope 0 at $DIR/generator-tiny.rs:21:9: 24:10
-    let mut _5: ();                      // in scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-    let _6: u8;                          // in scope 0 at $DIR/generator-tiny.rs:22:13: 22:18
-    let mut _7: ();                      // in scope 0 at $DIR/generator-tiny.rs:22:13: 22:18
-    let _8: ();                          // in scope 0 at $DIR/generator-tiny.rs:23:13: 23:21
-    let mut _9: ();                      // in scope 0 at $DIR/generator-tiny.rs:19:25: 19:25
+    let mut _0: std::ops::GeneratorState<(), ()>; // return place in scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+    let _3: HasDrop;                     // in scope 0 at $DIR/generator-tiny.rs:+1:13: +1:15
+    let mut _4: !;                       // in scope 0 at $DIR/generator-tiny.rs:+2:9: +5:10
+    let mut _5: ();                      // in scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+    let _6: u8;                          // in scope 0 at $DIR/generator-tiny.rs:+3:13: +3:18
+    let mut _7: ();                      // in scope 0 at $DIR/generator-tiny.rs:+3:13: +3:18
+    let _8: ();                          // in scope 0 at $DIR/generator-tiny.rs:+4:13: +4:21
+    let mut _9: ();                      // in scope 0 at $DIR/generator-tiny.rs:+0:25: +0:25
     let _10: u8;                         // in scope 0 at $DIR/generator-tiny.rs:+0:17: +0:19
-    let mut _11: u32;                    // in scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
+    let mut _11: u32;                    // in scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
     scope 1 {
-        debug _d => (((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24])) as variant#3).0: HasDrop); // in scope 1 at $DIR/generator-tiny.rs:20:13: 20:15
+        debug _d => (((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24])) as variant#3).0: HasDrop); // in scope 1 at $DIR/generator-tiny.rs:+1:13: +1:15
     }
 
     bb0: {
-        _11 = discriminant((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24]))); // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-        switchInt(move _11) -> [0_u32: bb1, 3_u32: bb5, otherwise: bb6]; // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
+        _11 = discriminant((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24]))); // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+        switchInt(move _11) -> [0_u32: bb1, 3_u32: bb5, otherwise: bb6]; // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
     }
 
     bb1: {
-        _10 = move _2;                   // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-        nop;                             // scope 0 at $DIR/generator-tiny.rs:20:13: 20:15
-        (((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24])) as variant#3).0: HasDrop) = HasDrop; // scope 0 at $DIR/generator-tiny.rs:20:18: 20:25
-        StorageLive(_4);                 // scope 1 at $DIR/generator-tiny.rs:21:9: 24:10
-        goto -> bb2;                     // scope 1 at $DIR/generator-tiny.rs:21:9: 24:10
+        _10 = move _2;                   // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+        nop;                             // scope 0 at $DIR/generator-tiny.rs:+1:13: +1:15
+        (((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24])) as variant#3).0: HasDrop) = HasDrop; // scope 0 at $DIR/generator-tiny.rs:+1:18: +1:25
+        StorageLive(_4);                 // scope 1 at $DIR/generator-tiny.rs:+2:9: +5:10
+        goto -> bb2;                     // scope 1 at $DIR/generator-tiny.rs:+2:9: +5:10
     }
 
     bb2: {
-        StorageLive(_6);                 // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        StorageLive(_7);                 // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        _7 = ();                         // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        Deinit(_0);                      // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        ((_0 as Yielded).0: ()) = move _7; // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        discriminant(_0) = 0;            // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        discriminant((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24]))) = 3; // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
-        return;                          // scope 1 at $DIR/generator-tiny.rs:22:13: 22:18
+        StorageLive(_6);                 // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        StorageLive(_7);                 // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        _7 = ();                         // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        Deinit(_0);                      // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        ((_0 as Yielded).0: ()) = move _7; // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        discriminant(_0) = 0;            // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        discriminant((*(_1.0: &mut [generator@$DIR/generator-tiny.rs:19:16: 19:24]))) = 3; // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
+        return;                          // scope 1 at $DIR/generator-tiny.rs:+3:13: +3:18
     }
 
     bb3: {
-        StorageDead(_7);                 // scope 1 at $DIR/generator-tiny.rs:22:17: 22:18
-        StorageDead(_6);                 // scope 1 at $DIR/generator-tiny.rs:22:18: 22:19
-        StorageLive(_8);                 // scope 1 at $DIR/generator-tiny.rs:23:13: 23:21
-        _8 = callee() -> bb4;            // scope 1 at $DIR/generator-tiny.rs:23:13: 23:21
+        StorageDead(_7);                 // scope 1 at $DIR/generator-tiny.rs:+3:17: +3:18
+        StorageDead(_6);                 // scope 1 at $DIR/generator-tiny.rs:+3:18: +3:19
+        StorageLive(_8);                 // scope 1 at $DIR/generator-tiny.rs:+4:13: +4:21
+        _8 = callee() -> bb4;            // scope 1 at $DIR/generator-tiny.rs:+4:13: +4:21
                                          // mir::Constant
                                          // + span: $DIR/generator-tiny.rs:23:13: 23:19
                                          // + literal: Const { ty: fn() {callee}, val: Value(<ZST>) }
     }
 
     bb4: {
-        StorageDead(_8);                 // scope 1 at $DIR/generator-tiny.rs:23:21: 23:22
-        _5 = const ();                   // scope 1 at $DIR/generator-tiny.rs:21:14: 24:10
-        goto -> bb2;                     // scope 1 at $DIR/generator-tiny.rs:21:9: 24:10
+        StorageDead(_8);                 // scope 1 at $DIR/generator-tiny.rs:+4:21: +4:22
+        _5 = const ();                   // scope 1 at $DIR/generator-tiny.rs:+2:14: +5:10
+        goto -> bb2;                     // scope 1 at $DIR/generator-tiny.rs:+2:9: +5:10
     }
 
     bb5: {
-        StorageLive(_4);                 // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-        StorageLive(_6);                 // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-        StorageLive(_7);                 // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-        _6 = move _2;                    // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
-        goto -> bb3;                     // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
+        StorageLive(_4);                 // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+        StorageLive(_6);                 // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+        StorageLive(_7);                 // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+        _6 = move _2;                    // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
+        goto -> bb3;                     // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
     }
 
     bb6: {
-        unreachable;                     // scope 0 at $DIR/generator-tiny.rs:+0:16: +0:24
+        unreachable;                     // scope 0 at $DIR/generator-tiny.rs:+0:16: +6:6
     }
 }
diff --git a/src/test/mir-opt/inline/cycle.f.Inline.diff b/src/test/mir-opt/inline/cycle.f.Inline.diff
index 40fdd1cdb19c..75ea69a42eb5 100644
--- a/src/test/mir-opt/inline/cycle.f.Inline.diff
+++ b/src/test/mir-opt/inline/cycle.f.Inline.diff
@@ -17,7 +17,7 @@
           _2 = <impl Fn() as Fn<()>>::call(move _3, move _4) -> [return: bb1, unwind: bb3]; // scope 0 at $DIR/cycle.rs:+1:5: +1:8
                                            // mir::Constant
                                            // + span: $DIR/cycle.rs:6:5: 6:6
-                                           // + literal: Const { ty: for<'r> extern "rust-call" fn(&'r impl Fn(), ()) -> <impl Fn() as FnOnce<()>>::Output {<impl Fn() as Fn<()>>::call}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a impl Fn(), ()) -> <impl Fn() as FnOnce<()>>::Output {<impl Fn() as Fn<()>>::call}, val: Value(<ZST>) }
       }
   
       bb1: {
diff --git a/src/test/mir-opt/inline/dyn_trait.get_query.Inline.diff b/src/test/mir-opt/inline/dyn_trait.get_query.Inline.diff
index 4b50ba9501c1..1e95b5b29ff4 100644
--- a/src/test/mir-opt/inline/dyn_trait.get_query.Inline.diff
+++ b/src/test/mir-opt/inline/dyn_trait.get_query.Inline.diff
@@ -28,7 +28,7 @@
                                            // mir::Constant
                                            // + span: $DIR/dyn-trait.rs:33:13: 33:21
                                            // + user_ty: UserType(0)
-                                           // + literal: Const { ty: for<'r> fn(&'r T) -> &'r <Q as Query>::C {<Q as Query>::cache::<T>}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a T) -> &'a <Q as Query>::C {<Q as Query>::cache::<T>}, val: Value(<ZST>) }
       }
   
       bb1: {
@@ -46,9 +46,9 @@
 +         _0 = <dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache(move _7) -> bb2; // scope 3 at $DIR/dyn-trait.rs:21:5: 21:22
                                            // mir::Constant
 -                                          // + span: $DIR/dyn-trait.rs:34:5: 34:22
--                                          // + literal: Const { ty: for<'r> fn(&'r <Q as Query>::C) {try_execute_query::<<Q as Query>::C>}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(&'a <Q as Query>::C) {try_execute_query::<<Q as Query>::C>}, val: Value(<ZST>) }
 +                                          // + span: $DIR/dyn-trait.rs:21:7: 21:20
-+                                          // + literal: Const { ty: for<'r> fn(&'r dyn Cache<V = <Q as Query>::V>) {<dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
++                                          // + literal: Const { ty: for<'a> fn(&'a dyn Cache<V = <Q as Query>::V>) {<dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
       }
   
       bb2: {
diff --git a/src/test/mir-opt/inline/dyn_trait.mk_cycle.Inline.diff b/src/test/mir-opt/inline/dyn_trait.mk_cycle.Inline.diff
index 994930ef4cf6..7421db4d063a 100644
--- a/src/test/mir-opt/inline/dyn_trait.mk_cycle.Inline.diff
+++ b/src/test/mir-opt/inline/dyn_trait.mk_cycle.Inline.diff
@@ -12,7 +12,7 @@
           _0 = <dyn Cache<V = V> as Cache>::store_nocache(move _2) -> bb1; // scope 0 at $DIR/dyn-trait.rs:+1:5: +1:22
                                            // mir::Constant
                                            // + span: $DIR/dyn-trait.rs:21:7: 21:20
-                                           // + literal: Const { ty: for<'r> fn(&'r dyn Cache<V = V>) {<dyn Cache<V = V> as Cache>::store_nocache}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a dyn Cache<V = V>) {<dyn Cache<V = V> as Cache>::store_nocache}, val: Value(<ZST>) }
       }
   
       bb1: {
diff --git a/src/test/mir-opt/inline/dyn_trait.try_execute_query.Inline.diff b/src/test/mir-opt/inline/dyn_trait.try_execute_query.Inline.diff
index 58c05b9f564d..e6e783744227 100644
--- a/src/test/mir-opt/inline/dyn_trait.try_execute_query.Inline.diff
+++ b/src/test/mir-opt/inline/dyn_trait.try_execute_query.Inline.diff
@@ -23,9 +23,9 @@
 +         _0 = <dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache(move _4) -> bb1; // scope 1 at $DIR/dyn-trait.rs:21:5: 21:22
                                            // mir::Constant
 -                                          // + span: $DIR/dyn-trait.rs:27:5: 27:13
--                                          // + literal: Const { ty: for<'r> fn(&'r (dyn Cache<V = <C as Cache>::V> + 'r)) {mk_cycle::<<C as Cache>::V>}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(&'a (dyn Cache<V = <C as Cache>::V> + 'a)) {mk_cycle::<<C as Cache>::V>}, val: Value(<ZST>) }
 +                                          // + span: $DIR/dyn-trait.rs:21:7: 21:20
-+                                          // + literal: Const { ty: for<'r> fn(&'r dyn Cache<V = <C as Cache>::V>) {<dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
++                                          // + literal: Const { ty: for<'a> fn(&'a dyn Cache<V = <C as Cache>::V>) {<dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
       }
   
       bb1: {
diff --git a/src/test/mir-opt/inline/inline-into-box-place.rs b/src/test/mir-opt/inline/inline-into-box-place.rs
index 049a97816f68..232bcc7b27d4 100644
--- a/src/test/mir-opt/inline/inline-into-box-place.rs
+++ b/src/test/mir-opt/inline/inline-into-box-place.rs
@@ -1,7 +1,7 @@
 // ignore-endian-big
 // ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -Z mir-opt-level=4
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 #![feature(box_syntax)]
 // EMIT_MIR inline_into_box_place.main.Inline.diff
 fn main() {
diff --git a/src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir b/src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir
index 4b075a8163bf..a2234e7c1eff 100644
--- a/src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir
+++ b/src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir
@@ -19,8 +19,8 @@ fn foo(_1: T, _2: i32) -> (i32, T) {
             debug t => (*((*_6).1: &T)); // in scope 2 at $DIR/inline-closure-captures.rs:+0:17: +0:18
             let mut _10: i32;            // in scope 2 at $DIR/inline-closure-captures.rs:+1:19: +1:20
             let mut _11: T;              // in scope 2 at $DIR/inline-closure-captures.rs:+1:22: +1:23
-            let mut _12: &i32;           // in scope 2 at $DIR/inline-closure-captures.rs:+1:13: +1:17
-            let mut _13: &T;             // in scope 2 at $DIR/inline-closure-captures.rs:+1:13: +1:17
+            let mut _12: &i32;           // in scope 2 at $DIR/inline-closure-captures.rs:+1:13: +1:24
+            let mut _13: &T;             // in scope 2 at $DIR/inline-closure-captures.rs:+1:13: +1:24
         }
     }
 
diff --git a/src/test/mir-opt/inline/inline_generator.main.Inline.diff b/src/test/mir-opt/inline/inline_generator.main.Inline.diff
index 669a787ae58f..3fd8aad72388 100644
--- a/src/test/mir-opt/inline/inline_generator.main.Inline.diff
+++ b/src/test/mir-opt/inline/inline_generator.main.Inline.diff
@@ -29,10 +29,10 @@
 +         let mut _9: bool;                // in scope 6 at $DIR/inline-generator.rs:15:20: 15:21
 +         let mut _10: bool;               // in scope 6 at $DIR/inline-generator.rs:15:9: 15:9
 +         let _11: bool;                   // in scope 6 at $DIR/inline-generator.rs:15:6: 15:7
-+         let mut _12: u32;                // in scope 6 at $DIR/inline-generator.rs:15:5: 15:8
-+         let mut _13: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:8
-+         let mut _14: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:8
-+         let mut _15: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:8
++         let mut _12: u32;                // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
++         let mut _13: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
++         let mut _14: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
++         let mut _15: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
 +     }
   
       bb0: {
@@ -70,14 +70,14 @@
 -         _1 = <[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::resume(move _2, const false) -> [return: bb3, unwind: bb4]; // scope 0 at $DIR/inline-generator.rs:+1:14: +1:46
 -                                          // mir::Constant
 -                                          // + span: $DIR/inline-generator.rs:9:33: 9:39
--                                          // + literal: Const { ty: for<'r> fn(Pin<&'r mut [generator@$DIR/inline-generator.rs:15:5: 15:8]>, bool) -> GeneratorState<<[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::Yield, <[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::Return> {<[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::resume}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(Pin<&'a mut [generator@$DIR/inline-generator.rs:15:5: 15:8]>, bool) -> GeneratorState<<[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::Yield, <[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::Return> {<[generator@$DIR/inline-generator.rs:15:5: 15:8] as Generator<bool>>::resume}, val: Value(<ZST>) }
 +         StorageLive(_7);                 // scope 0 at $DIR/inline-generator.rs:+1:14: +1:46
 +         _7 = const false;                // scope 0 at $DIR/inline-generator.rs:+1:14: +1:46
 +         StorageLive(_10);                // scope 0 at $DIR/inline-generator.rs:+1:14: +1:46
 +         StorageLive(_11);                // scope 0 at $DIR/inline-generator.rs:+1:14: +1:46
-+         _13 = deref_copy (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]); // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
-+         _12 = discriminant((*_13));      // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
-+         switchInt(move _12) -> [0_u32: bb3, 1_u32: bb8, 3_u32: bb7, otherwise: bb9]; // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
++         _13 = deref_copy (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]); // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
++         _12 = discriminant((*_13));      // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
++         switchInt(move _12) -> [0_u32: bb3, 1_u32: bb8, 3_u32: bb7, otherwise: bb9]; // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
       }
   
 -     bb3: {
@@ -98,7 +98,7 @@
 +     }
 + 
 +     bb3: {
-+         _11 = move _7;                   // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
++         _11 = move _7;                   // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
 +         StorageLive(_8);                 // scope 6 at $DIR/inline-generator.rs:15:17: 15:39
 +         StorageLive(_9);                 // scope 6 at $DIR/inline-generator.rs:15:20: 15:21
 +         _9 = _11;                        // scope 6 at $DIR/inline-generator.rs:15:20: 15:21
@@ -126,23 +126,23 @@
 +     }
 + 
 +     bb7: {
-+         StorageLive(_8);                 // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
-+         _10 = move _7;                   // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
++         StorageLive(_8);                 // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
++         _10 = move _7;                   // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
 +         StorageDead(_8);                 // scope 6 at $DIR/inline-generator.rs:15:38: 15:39
-+         Deinit(_1);                      // scope 6 at $DIR/inline-generator.rs:15:8: 15:8
-+         ((_1 as Complete).0: bool) = move _10; // scope 6 at $DIR/inline-generator.rs:15:8: 15:8
-+         discriminant(_1) = 1;            // scope 6 at $DIR/inline-generator.rs:15:8: 15:8
-+         _15 = deref_copy (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]); // scope 6 at $DIR/inline-generator.rs:15:8: 15:8
-+         discriminant((*_15)) = 1;        // scope 6 at $DIR/inline-generator.rs:15:8: 15:8
-+         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:8: 15:8
++         Deinit(_1);                      // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
++         ((_1 as Complete).0: bool) = move _10; // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
++         discriminant(_1) = 1;            // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
++         _15 = deref_copy (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:8]); // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
++         discriminant((*_15)) = 1;        // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
++         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:41: 15:41
 +     }
 + 
 +     bb8: {
-+         assert(const false, "generator resumed after completion") -> [success: bb8, unwind: bb2]; // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
++         assert(const false, "generator resumed after completion") -> [success: bb8, unwind: bb2]; // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
 +     }
 + 
 +     bb9: {
-+         unreachable;                     // scope 6 at $DIR/inline-generator.rs:15:5: 15:8
++         unreachable;                     // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
       }
   }
   
diff --git a/src/test/mir-opt/inline/inline_into_box_place.main.Inline.64bit.diff b/src/test/mir-opt/inline/inline_into_box_place.main.Inline.64bit.diff
deleted file mode 100644
index 7017413ad38a..000000000000
--- a/src/test/mir-opt/inline/inline_into_box_place.main.Inline.64bit.diff
+++ /dev/null
@@ -1,82 +0,0 @@
-- // MIR for `main` before Inline
-+ // MIR for `main` after Inline
-  
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/inline-into-box-place.rs:+0:11: +0:11
-      let _1: std::boxed::Box<std::vec::Vec<u32>>; // in scope 0 at $DIR/inline-into-box-place.rs:+1:9: +1:11
-      let mut _2: usize;                   // in scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-      let mut _3: usize;                   // in scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-      let mut _4: *mut u8;                 // in scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-      let mut _5: std::boxed::Box<std::vec::Vec<u32>>; // in scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-      let mut _6: ();                      // in scope 0 at $DIR/inline-into-box-place.rs:+1:42: +1:43
-      let mut _7: *const std::vec::Vec<u32>; // in scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-+     let mut _8: &mut std::vec::Vec<u32>; // in scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
-      scope 1 {
-          debug _x => _1;                  // in scope 1 at $DIR/inline-into-box-place.rs:+1:9: +1:11
-      }
-      scope 2 {
-      }
-+     scope 3 (inlined Vec::<u32>::new) {  // at $DIR/inline-into-box-place.rs:8:33: 8:43
-+         let mut _9: alloc::raw_vec::RawVec<u32>; // in scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+     }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:9: +1:11
-          _2 = SizeOf(std::vec::Vec<u32>); // scope 2 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-          _3 = AlignOf(std::vec::Vec<u32>); // scope 2 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-          _4 = alloc::alloc::exchange_malloc(move _2, move _3) -> bb1; // scope 2 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-                                           // mir::Constant
-                                           // + span: $DIR/inline-into-box-place.rs:8:29: 8:43
-                                           // + literal: Const { ty: unsafe fn(usize, usize) -> *mut u8 {alloc::alloc::exchange_malloc}, val: Value(<ZST>) }
-      }
-  
-      bb1: {
-          StorageLive(_5);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-          _5 = ShallowInitBox(move _4, std::vec::Vec<u32>); // scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-          _7 = (((_5.0: std::ptr::Unique<std::vec::Vec<u32>>).0: std::ptr::NonNull<std::vec::Vec<u32>>).0: *const std::vec::Vec<u32>); // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
--         (*_7) = Vec::<u32>::new() -> [return: bb2, unwind: bb5]; // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
-+         StorageLive(_8);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
-+         _8 = &mut (*_7);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
-+         StorageLive(_9);                 // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         _9 = const alloc::raw_vec::RawVec::<u32>::NEW; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-                                           // mir::Constant
--                                          // + span: $DIR/inline-into-box-place.rs:8:33: 8:41
--                                          // + user_ty: UserType(1)
--                                          // + literal: Const { ty: fn() -> Vec<u32> {Vec::<u32>::new}, val: Value(<ZST>) }
--     }
-- 
--     bb2: {
-+                                          // + span: $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+                                          // + user_ty: UserType(0)
-+                                          // + literal: Const { ty: alloc::raw_vec::RawVec<u32>, val: Unevaluated(alloc::raw_vec::RawVec::<T>::NEW, [u32], None) }
-+         Deinit((*_8));                   // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         ((*_8).0: alloc::raw_vec::RawVec<u32>) = move _9; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         ((*_8).1: usize) = const 0_usize; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         StorageDead(_9);                 // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         StorageDead(_8);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
-          _1 = move _5;                    // scope 0 at $DIR/inline-into-box-place.rs:+1:29: +1:43
-          StorageDead(_5);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:42: +1:43
-          _0 = const ();                   // scope 0 at $DIR/inline-into-box-place.rs:+0:11: +2:2
--         drop(_1) -> [return: bb3, unwind: bb4]; // scope 0 at $DIR/inline-into-box-place.rs:+2:1: +2:2
-+         drop(_1) -> [return: bb2, unwind: bb3]; // scope 0 at $DIR/inline-into-box-place.rs:+2:1: +2:2
-      }
-  
--     bb3: {
-+     bb2: {
-          StorageDead(_1);                 // scope 0 at $DIR/inline-into-box-place.rs:+2:1: +2:2
-          return;                          // scope 0 at $DIR/inline-into-box-place.rs:+2:2: +2:2
-      }
-  
--     bb4 (cleanup): {
-+     bb3 (cleanup): {
-          resume;                          // scope 0 at $DIR/inline-into-box-place.rs:+0:1: +2:2
--     }
-- 
--     bb5 (cleanup): {
--         _6 = alloc::alloc::box_free::<Vec<u32>, std::alloc::Global>(move (_5.0: std::ptr::Unique<std::vec::Vec<u32>>), move (_5.1: std::alloc::Global)) -> bb4; // scope 0 at $DIR/inline-into-box-place.rs:+1:42: +1:43
--                                          // mir::Constant
--                                          // + span: $DIR/inline-into-box-place.rs:8:42: 8:43
--                                          // + literal: Const { ty: unsafe fn(Unique<Vec<u32>>, std::alloc::Global) {alloc::alloc::box_free::<Vec<u32>, std::alloc::Global>}, val: Value(<ZST>) }
-      }
-  }
-  
diff --git a/src/test/mir-opt/inline/inline_into_box_place.main.Inline.32bit.diff b/src/test/mir-opt/inline/inline_into_box_place.main.Inline.diff
similarity index 98%
rename from src/test/mir-opt/inline/inline_into_box_place.main.Inline.32bit.diff
rename to src/test/mir-opt/inline/inline_into_box_place.main.Inline.diff
index 7017413ad38a..7e017373b441 100644
--- a/src/test/mir-opt/inline/inline_into_box_place.main.Inline.32bit.diff
+++ b/src/test/mir-opt/inline/inline_into_box_place.main.Inline.diff
@@ -38,7 +38,7 @@
 +         StorageLive(_8);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
 +         _8 = &mut (*_7);                 // scope 0 at $DIR/inline-into-box-place.rs:+1:33: +1:43
 +         StorageLive(_9);                 // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         _9 = const alloc::raw_vec::RawVec::<u32>::NEW; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         _9 = const _;                    // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
                                            // mir::Constant
 -                                          // + span: $DIR/inline-into-box-place.rs:8:33: 8:41
 -                                          // + user_ty: UserType(1)
diff --git a/src/test/mir-opt/inline/inline_retag.bar.Inline.after.mir b/src/test/mir-opt/inline/inline_retag.bar.Inline.after.mir
index d5410d3afd4a..169e7f5c5d93 100644
--- a/src/test/mir-opt/inline/inline_retag.bar.Inline.after.mir
+++ b/src/test/mir-opt/inline/inline_retag.bar.Inline.after.mir
@@ -2,8 +2,8 @@
 
 fn bar() -> bool {
     let mut _0: bool;                    // return place in scope 0 at $DIR/inline-retag.rs:+0:13: +0:17
-    let _1: for<'r, 's> fn(&'r i32, &'s i32) -> bool {foo}; // in scope 0 at $DIR/inline-retag.rs:+1:9: +1:10
-    let mut _2: for<'r, 's> fn(&'r i32, &'s i32) -> bool {foo}; // in scope 0 at $DIR/inline-retag.rs:+2:5: +2:6
+    let _1: for<'a, 'b> fn(&'a i32, &'b i32) -> bool {foo}; // in scope 0 at $DIR/inline-retag.rs:+1:9: +1:10
+    let mut _2: for<'a, 'b> fn(&'a i32, &'b i32) -> bool {foo}; // in scope 0 at $DIR/inline-retag.rs:+2:5: +2:6
     let mut _3: &i32;                    // in scope 0 at $DIR/inline-retag.rs:+2:7: +2:9
     let _4: &i32;                        // in scope 0 at $DIR/inline-retag.rs:+2:7: +2:9
     let _5: i32;                         // in scope 0 at $DIR/inline-retag.rs:+2:8: +2:9
@@ -27,12 +27,12 @@ fn bar() -> bool {
         _1 = foo;                        // scope 0 at $DIR/inline-retag.rs:+1:13: +1:16
                                          // mir::Constant
                                          // + span: $DIR/inline-retag.rs:11:13: 11:16
-                                         // + literal: Const { ty: for<'r, 's> fn(&'r i32, &'s i32) -> bool {foo}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b> fn(&'a i32, &'b i32) -> bool {foo}, val: Value(<ZST>) }
         StorageLive(_2);                 // scope 1 at $DIR/inline-retag.rs:+2:5: +2:6
         _2 = _1;                         // scope 1 at $DIR/inline-retag.rs:+2:5: +2:6
         StorageLive(_3);                 // scope 1 at $DIR/inline-retag.rs:+2:7: +2:9
         StorageLive(_4);                 // scope 1 at $DIR/inline-retag.rs:+2:7: +2:9
-        _10 = const bar::promoted[1];    // scope 1 at $DIR/inline-retag.rs:+2:7: +2:9
+        _10 = const _;                   // scope 1 at $DIR/inline-retag.rs:+2:7: +2:9
                                          // mir::Constant
                                          // + span: $DIR/inline-retag.rs:12:7: 12:9
                                          // + literal: Const { ty: &i32, val: Unevaluated(bar, [], Some(promoted[1])) }
@@ -43,7 +43,7 @@ fn bar() -> bool {
         Retag(_3);                       // scope 1 at $DIR/inline-retag.rs:+2:7: +2:9
         StorageLive(_6);                 // scope 1 at $DIR/inline-retag.rs:+2:11: +2:14
         StorageLive(_7);                 // scope 1 at $DIR/inline-retag.rs:+2:11: +2:14
-        _9 = const bar::promoted[0];     // scope 1 at $DIR/inline-retag.rs:+2:11: +2:14
+        _9 = const _;                    // scope 1 at $DIR/inline-retag.rs:+2:11: +2:14
                                          // mir::Constant
                                          // + span: $DIR/inline-retag.rs:12:11: 12:14
                                          // + literal: Const { ty: &i32, val: Unevaluated(bar, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/inline/inline_shims.clone.Inline.diff b/src/test/mir-opt/inline/inline_shims.clone.Inline.diff
index 25ca05893b2e..d691e90b7dac 100644
--- a/src/test/mir-opt/inline/inline_shims.clone.Inline.diff
+++ b/src/test/mir-opt/inline/inline_shims.clone.Inline.diff
@@ -14,7 +14,7 @@
 -         _0 = <fn(A, B) as Clone>::clone(move _2) -> bb1; // scope 0 at $DIR/inline-shims.rs:+1:5: +1:14
 -                                          // mir::Constant
 -                                          // + span: $DIR/inline-shims.rs:6:7: 6:12
--                                          // + literal: Const { ty: for<'r> fn(&'r fn(A, B)) -> fn(A, B) {<fn(A, B) as Clone>::clone}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(&'a fn(A, B)) -> fn(A, B) {<fn(A, B) as Clone>::clone}, val: Value(<ZST>) }
 -     }
 - 
 -     bb1: {
diff --git a/src/test/mir-opt/inline/inline_trait_method.test.Inline.after.mir b/src/test/mir-opt/inline/inline_trait_method.test.Inline.after.mir
index ed95edd16ce7..89eefc292691 100644
--- a/src/test/mir-opt/inline/inline_trait_method.test.Inline.after.mir
+++ b/src/test/mir-opt/inline/inline_trait_method.test.Inline.after.mir
@@ -11,7 +11,7 @@ fn test(_1: &dyn X) -> u32 {
         _0 = <dyn X as X>::y(move _2) -> bb1; // scope 0 at $DIR/inline-trait-method.rs:+1:5: +1:10
                                          // mir::Constant
                                          // + span: $DIR/inline-trait-method.rs:9:7: 9:8
-                                         // + literal: Const { ty: for<'r> fn(&'r dyn X) -> u32 {<dyn X as X>::y}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a dyn X) -> u32 {<dyn X as X>::y}, val: Value(<ZST>) }
     }
 
     bb1: {
diff --git a/src/test/mir-opt/inline/inline_trait_method_2.test2.Inline.after.mir b/src/test/mir-opt/inline/inline_trait_method_2.test2.Inline.after.mir
index b8896430d221..3d05869fa513 100644
--- a/src/test/mir-opt/inline/inline_trait_method_2.test2.Inline.after.mir
+++ b/src/test/mir-opt/inline/inline_trait_method_2.test2.Inline.after.mir
@@ -21,7 +21,7 @@ fn test2(_1: &dyn X) -> bool {
         _0 = <dyn X as X>::y(move _4) -> bb1; // scope 1 at $DIR/inline-trait-method_2.rs:10:5: 10:10
                                          // mir::Constant
                                          // + span: $DIR/inline-trait-method_2.rs:10:7: 10:8
-                                         // + literal: Const { ty: for<'r> fn(&'r dyn X) -> bool {<dyn X as X>::y}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a dyn X) -> bool {<dyn X as X>::y}, val: Value(<ZST>) }
     }
 
     bb1: {
diff --git a/src/test/mir-opt/inline/issue_78442.bar.Inline.diff b/src/test/mir-opt/inline/issue_78442.bar.Inline.diff
index c16dfdf395ec..4186650dfabe 100644
--- a/src/test/mir-opt/inline/issue_78442.bar.Inline.diff
+++ b/src/test/mir-opt/inline/issue_78442.bar.Inline.diff
@@ -29,7 +29,7 @@
 -         _2 = <fn() {foo} as Fn<()>>::call(move _3, move _5) -> [return: bb2, unwind: bb4]; // scope 0 at $DIR/issue-78442.rs:+4:5: +4:17
 -                                          // mir::Constant
 -                                          // + span: $DIR/issue-78442.rs:11:5: 11:15
--                                          // + literal: Const { ty: for<'r> extern "rust-call" fn(&'r fn() {foo}, ()) -> <fn() {foo} as FnOnce<()>>::Output {<fn() {foo} as Fn<()>>::call}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a fn() {foo}, ()) -> <fn() {foo} as FnOnce<()>>::Output {<fn() {foo} as Fn<()>>::call}, val: Value(<ZST>) }
 +         _2 = move (*_3)() -> [return: bb5, unwind: bb3]; // scope 1 at $SRC_DIR/core/src/ops/function.rs:LL:COL
       }
   
diff --git a/src/test/mir-opt/inline/issue_78442.bar.RevealAll.diff b/src/test/mir-opt/inline/issue_78442.bar.RevealAll.diff
index 0faa522cbaa9..24e9a3df15ac 100644
--- a/src/test/mir-opt/inline/issue_78442.bar.RevealAll.diff
+++ b/src/test/mir-opt/inline/issue_78442.bar.RevealAll.diff
@@ -29,8 +29,8 @@
 +         _2 = <fn() {foo} as Fn<()>>::call(move _3, move _5) -> [return: bb2, unwind: bb4]; // scope 0 at $DIR/issue-78442.rs:+4:5: +4:17
                                            // mir::Constant
                                            // + span: $DIR/issue-78442.rs:11:5: 11:15
--                                          // + literal: Const { ty: for<'r> extern "rust-call" fn(&'r impl Fn(), ()) -> <impl Fn() as FnOnce<()>>::Output {<impl Fn() as Fn<()>>::call}, val: Value(<ZST>) }
-+                                          // + literal: Const { ty: for<'r> extern "rust-call" fn(&'r fn() {foo}, ()) -> <fn() {foo} as FnOnce<()>>::Output {<fn() {foo} as Fn<()>>::call}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a impl Fn(), ()) -> <impl Fn() as FnOnce<()>>::Output {<impl Fn() as Fn<()>>::call}, val: Value(<ZST>) }
++                                          // + literal: Const { ty: for<'a> extern "rust-call" fn(&'a fn() {foo}, ()) -> <fn() {foo} as FnOnce<()>>::Output {<fn() {foo} as Fn<()>>::call}, val: Value(<ZST>) }
       }
   
       bb2: {
diff --git a/src/test/mir-opt/issue-101867.rs b/src/test/mir-opt/issue-101867.rs
new file mode 100644
index 000000000000..8a357eb79951
--- /dev/null
+++ b/src/test/mir-opt/issue-101867.rs
@@ -0,0 +1,7 @@
+// EMIT_MIR issue_101867.main.mir_map.0.mir
+fn main() {
+    let x: Option<u8> = Some(1);
+    let Some(y) = x else {
+        panic!();
+    };
+}
diff --git a/src/test/mir-opt/issue-101973.rs b/src/test/mir-opt/issue-101973.rs
new file mode 100644
index 000000000000..216659a235ef
--- /dev/null
+++ b/src/test/mir-opt/issue-101973.rs
@@ -0,0 +1,20 @@
+// compile-flags: -O -C debug-assertions=on
+// This needs inlining followed by ConstProp to reproduce, so we cannot use "unit-test".
+
+#[inline]
+pub fn imm8(x: u32) -> u32 {
+    let mut out = 0u32;
+    out |= (x >> 0) & 0xff;
+    out
+}
+
+// EMIT_MIR issue_101973.inner.ConstProp.diff
+#[inline(never)]
+pub fn inner(fields: u32) -> i64 {
+    imm8(fields).rotate_right(((fields >> 8) & 0xf) << 1) as i32 as i64
+}
+
+fn main() {
+    let val = inner(0xe32cf20f);
+    assert_eq!(val as u64, 0xfffffffff0000000);
+}
diff --git a/src/test/mir-opt/issue-41697.rs b/src/test/mir-opt/issue-41697.rs
index 5c34d8e68d0c..cbd8633a345c 100644
--- a/src/test/mir-opt/issue-41697.rs
+++ b/src/test/mir-opt/issue-41697.rs
@@ -13,7 +13,7 @@ trait Foo {
     fn get(&self) -> [u8; 2];
 }
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.mir
 impl Foo for [u8; 1+1] {
     fn get(&self) -> [u8; 2] {
diff --git a/src/test/mir-opt/issue-72181.rs b/src/test/mir-opt/issue-72181.rs
index 844d53a4b2bc..ebb5f5042fcc 100644
--- a/src/test/mir-opt/issue-72181.rs
+++ b/src/test/mir-opt/issue-72181.rs
@@ -11,14 +11,14 @@ union Foo {
     b: Never
 }
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR issue_72181.foo.mir_map.0.mir
 fn foo(xs: [(Never, u32); 1]) -> u32 { xs[0].1 }
 
 // EMIT_MIR issue_72181.bar.mir_map.0.mir
 fn bar([(_, x)]: [(Never, u32); 1]) -> u32 { x }
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR issue_72181.main.mir_map.0.mir
 fn main() {
     let _ = mem::size_of::<Foo>();
diff --git a/src/test/mir-opt/issue-73223.rs b/src/test/mir-opt/issue-73223.rs
index 703b87612313..be114cab719c 100644
--- a/src/test/mir-opt/issue-73223.rs
+++ b/src/test/mir-opt/issue-73223.rs
@@ -8,6 +8,5 @@ fn main() {
     assert_eq!(split, 1);
 }
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR issue_73223.main.SimplifyArmIdentity.diff
-// EMIT_MIR issue_73223.main.PreCodegen.diff
diff --git a/src/test/mir-opt/issue_101867.main.mir_map.0.mir b/src/test/mir-opt/issue_101867.main.mir_map.0.mir
new file mode 100644
index 000000000000..42a9e5587603
--- /dev/null
+++ b/src/test/mir-opt/issue_101867.main.mir_map.0.mir
@@ -0,0 +1,75 @@
+// MIR for `main` 0 mir_map
+
+| User Type Annotations
+| 0: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<u8>) }, span: $DIR/issue-101867.rs:3:12: 3:22, inferred_ty: std::option::Option<u8>
+| 1: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<u8>) }, span: $DIR/issue-101867.rs:3:12: 3:22, inferred_ty: std::option::Option<u8>
+|
+fn main() -> () {
+    let mut _0: ();                      // return place in scope 0 at $DIR/issue-101867.rs:+0:11: +0:11
+    let _1: std::option::Option<u8> as UserTypeProjection { base: UserType(0), projs: [] }; // in scope 0 at $DIR/issue-101867.rs:+1:9: +1:10
+    let mut _2: !;                       // in scope 0 at $DIR/issue-101867.rs:+2:26: +4:6
+    let _3: ();                          // in scope 0 at $SRC_DIR/std/src/panic.rs:LL:COL
+    let mut _4: !;                       // in scope 0 at $SRC_DIR/std/src/panic.rs:LL:COL
+    let mut _6: isize;                   // in scope 0 at $DIR/issue-101867.rs:+2:9: +2:16
+    scope 1 {
+        debug x => _1;                   // in scope 1 at $DIR/issue-101867.rs:+1:9: +1:10
+        let _5: u8;                      // in scope 1 at $DIR/issue-101867.rs:+2:14: +2:15
+        scope 2 {
+            debug y => _5;               // in scope 2 at $DIR/issue-101867.rs:+2:14: +2:15
+        }
+    }
+
+    bb0: {
+        StorageLive(_1);                 // scope 0 at $DIR/issue-101867.rs:+1:9: +1:10
+        _1 = Option::<u8>::Some(const 1_u8); // scope 0 at $DIR/issue-101867.rs:+1:25: +1:32
+        FakeRead(ForLet(None), _1);      // scope 0 at $DIR/issue-101867.rs:+1:9: +1:10
+        AscribeUserType(_1, o, UserTypeProjection { base: UserType(1), projs: [] }); // scope 0 at $DIR/issue-101867.rs:+1:12: +1:22
+        StorageLive(_5);                 // scope 1 at $DIR/issue-101867.rs:+2:14: +2:15
+        FakeRead(ForMatchedPlace(None), _1); // scope 1 at $DIR/issue-101867.rs:+2:19: +2:20
+        _6 = discriminant(_1);           // scope 1 at $DIR/issue-101867.rs:+2:19: +2:20
+        switchInt(move _6) -> [1_isize: bb4, otherwise: bb3]; // scope 1 at $DIR/issue-101867.rs:+2:9: +2:16
+    }
+
+    bb1: {
+        StorageLive(_3);                 // scope 1 at $SRC_DIR/std/src/panic.rs:LL:COL
+        StorageLive(_4);                 // scope 1 at $SRC_DIR/std/src/panic.rs:LL:COL
+        _4 = begin_panic::<&str>(const "explicit panic") -> bb7; // scope 1 at $SRC_DIR/std/src/panic.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/std/src/panic.rs:LL:COL
+                                         // + literal: Const { ty: fn(&str) -> ! {begin_panic::<&str>}, val: Value(<ZST>) }
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/std/src/panic.rs:LL:COL
+                                         // + literal: Const { ty: &str, val: Value(Slice(..)) }
+    }
+
+    bb2: {
+        StorageDead(_4);                 // scope 1 at $SRC_DIR/std/src/panic.rs:LL:COL
+        StorageDead(_3);                 // scope 1 at $DIR/issue-101867.rs:+3:16: +3:17
+        unreachable;                     // scope 1 at $DIR/issue-101867.rs:+2:26: +4:6
+    }
+
+    bb3: {
+        goto -> bb6;                     // scope 1 at $DIR/issue-101867.rs:+2:19: +2:20
+    }
+
+    bb4: {
+        falseEdge -> [real: bb5, imaginary: bb3]; // scope 1 at $DIR/issue-101867.rs:+2:9: +2:16
+    }
+
+    bb5: {
+        _5 = ((_1 as Some).0: u8);       // scope 1 at $DIR/issue-101867.rs:+2:14: +2:15
+        _0 = const ();                   // scope 0 at $DIR/issue-101867.rs:+0:11: +5:2
+        StorageDead(_5);                 // scope 1 at $DIR/issue-101867.rs:+5:1: +5:2
+        StorageDead(_1);                 // scope 0 at $DIR/issue-101867.rs:+5:1: +5:2
+        return;                          // scope 0 at $DIR/issue-101867.rs:+5:2: +5:2
+    }
+
+    bb6: {
+        StorageDead(_5);                 // scope 1 at $DIR/issue-101867.rs:+5:1: +5:2
+        goto -> bb1;                     // scope 0 at $DIR/issue-101867.rs:+0:11: +5:2
+    }
+
+    bb7 (cleanup): {
+        resume;                          // scope 0 at $DIR/issue-101867.rs:+0:1: +5:2
+    }
+}
diff --git a/src/test/mir-opt/issue_101973.inner.ConstProp.diff b/src/test/mir-opt/issue_101973.inner.ConstProp.diff
new file mode 100644
index 000000000000..89733a9a2cb7
--- /dev/null
+++ b/src/test/mir-opt/issue_101973.inner.ConstProp.diff
@@ -0,0 +1,100 @@
+- // MIR for `inner` before ConstProp
++ // MIR for `inner` after ConstProp
+  
+  fn inner(_1: u32) -> i64 {
+      debug fields => _1;                  // in scope 0 at $DIR/issue-101973.rs:+0:14: +0:20
+      let mut _0: i64;                     // return place in scope 0 at $DIR/issue-101973.rs:+0:30: +0:33
+      let mut _2: i32;                     // in scope 0 at $DIR/issue-101973.rs:+1:5: +1:65
+      let mut _3: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:5: +1:58
+      let mut _4: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:5: +1:17
+      let mut _5: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:10: +1:16
+      let mut _6: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:31: +1:57
+      let mut _7: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:31: +1:52
+      let mut _8: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:32: +1:45
+      let mut _9: u32;                     // in scope 0 at $DIR/issue-101973.rs:+1:33: +1:39
+      let mut _10: (u32, bool);            // in scope 0 at $DIR/issue-101973.rs:+1:32: +1:45
+      let mut _11: (u32, bool);            // in scope 0 at $DIR/issue-101973.rs:+1:31: +1:57
+      scope 1 (inlined imm8) {             // at $DIR/issue-101973.rs:14:5: 14:17
+          debug x => _5;                   // in scope 1 at $DIR/issue-101973.rs:5:13: 5:14
+          let mut _12: u32;                // in scope 1 at $DIR/issue-101973.rs:7:12: 7:27
+          let mut _13: u32;                // in scope 1 at $DIR/issue-101973.rs:7:12: 7:20
+          let mut _14: u32;                // in scope 1 at $DIR/issue-101973.rs:7:13: 7:14
+          let mut _15: (u32, bool);        // in scope 1 at $DIR/issue-101973.rs:7:12: 7:20
+          scope 2 {
+              debug out => _4;             // in scope 2 at $DIR/issue-101973.rs:6:9: 6:16
+          }
+      }
+      scope 3 (inlined core::num::<impl u32>::rotate_right) { // at $DIR/issue-101973.rs:14:5: 14:58
+          debug self => _4;                // in scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          debug n => _6;                   // in scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          let mut _16: u32;                // in scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          let mut _17: u32;                // in scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+      }
+  
+      bb0: {
+          StorageLive(_2);                 // scope 0 at $DIR/issue-101973.rs:+1:5: +1:65
+          StorageLive(_3);                 // scope 0 at $DIR/issue-101973.rs:+1:5: +1:58
+          StorageLive(_4);                 // scope 0 at $DIR/issue-101973.rs:+1:5: +1:17
+          StorageLive(_5);                 // scope 0 at $DIR/issue-101973.rs:+1:10: +1:16
+          _5 = _1;                         // scope 0 at $DIR/issue-101973.rs:+1:10: +1:16
+          _4 = const 0_u32;                // scope 1 at $DIR/issue-101973.rs:6:19: 6:23
+          StorageLive(_12);                // scope 2 at $DIR/issue-101973.rs:7:12: 7:27
+          StorageLive(_13);                // scope 2 at $DIR/issue-101973.rs:7:12: 7:20
+          StorageLive(_14);                // scope 2 at $DIR/issue-101973.rs:7:13: 7:14
+          _14 = _5;                        // scope 2 at $DIR/issue-101973.rs:7:13: 7:14
+          _15 = CheckedShr(_14, const 0_i32); // scope 2 at $DIR/issue-101973.rs:7:12: 7:20
+          assert(!move (_15.1: bool), "attempt to shift right by `{}`, which would overflow", const 0_i32) -> bb3; // scope 2 at $DIR/issue-101973.rs:7:12: 7:20
+      }
+  
+      bb1: {
+          _8 = move (_10.0: u32);          // scope 0 at $DIR/issue-101973.rs:+1:32: +1:45
+          StorageDead(_9);                 // scope 0 at $DIR/issue-101973.rs:+1:44: +1:45
+          _7 = BitAnd(move _8, const 15_u32); // scope 0 at $DIR/issue-101973.rs:+1:31: +1:52
+          StorageDead(_8);                 // scope 0 at $DIR/issue-101973.rs:+1:51: +1:52
+          _11 = CheckedShl(_7, const 1_i32); // scope 0 at $DIR/issue-101973.rs:+1:31: +1:57
+          assert(!move (_11.1: bool), "attempt to shift left by `{}`, which would overflow", const 1_i32) -> bb2; // scope 0 at $DIR/issue-101973.rs:+1:31: +1:57
+      }
+  
+      bb2: {
+          _6 = move (_11.0: u32);          // scope 0 at $DIR/issue-101973.rs:+1:31: +1:57
+          StorageDead(_7);                 // scope 0 at $DIR/issue-101973.rs:+1:56: +1:57
+          StorageLive(_16);                // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          _16 = _4;                        // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          StorageLive(_17);                // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          _17 = _6;                        // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          _3 = rotate_right::<u32>(move _16, move _17) -> bb4; // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+                                           // mir::Constant
+                                           // + span: $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+                                           // + literal: Const { ty: extern "rust-intrinsic" fn(u32, u32) -> u32 {rotate_right::<u32>}, val: Value(<ZST>) }
+      }
+  
+      bb3: {
+          _13 = move (_15.0: u32);         // scope 2 at $DIR/issue-101973.rs:7:12: 7:20
+          StorageDead(_14);                // scope 2 at $DIR/issue-101973.rs:7:19: 7:20
+          _12 = BitAnd(move _13, const 255_u32); // scope 2 at $DIR/issue-101973.rs:7:12: 7:27
+          StorageDead(_13);                // scope 2 at $DIR/issue-101973.rs:7:26: 7:27
+          _4 = BitOr(_4, move _12);        // scope 2 at $DIR/issue-101973.rs:7:5: 7:27
+          StorageDead(_12);                // scope 2 at $DIR/issue-101973.rs:7:26: 7:27
+          StorageDead(_5);                 // scope 0 at $DIR/issue-101973.rs:+1:16: +1:17
+          StorageLive(_6);                 // scope 0 at $DIR/issue-101973.rs:+1:31: +1:57
+          StorageLive(_7);                 // scope 0 at $DIR/issue-101973.rs:+1:31: +1:52
+          StorageLive(_8);                 // scope 0 at $DIR/issue-101973.rs:+1:32: +1:45
+          StorageLive(_9);                 // scope 0 at $DIR/issue-101973.rs:+1:33: +1:39
+          _9 = _1;                         // scope 0 at $DIR/issue-101973.rs:+1:33: +1:39
+          _10 = CheckedShr(_9, const 8_i32); // scope 0 at $DIR/issue-101973.rs:+1:32: +1:45
+          assert(!move (_10.1: bool), "attempt to shift right by `{}`, which would overflow", const 8_i32) -> bb1; // scope 0 at $DIR/issue-101973.rs:+1:32: +1:45
+      }
+  
+      bb4: {
+          StorageDead(_17);                // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          StorageDead(_16);                // scope 3 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+          StorageDead(_6);                 // scope 0 at $DIR/issue-101973.rs:+1:57: +1:58
+          StorageDead(_4);                 // scope 0 at $DIR/issue-101973.rs:+1:57: +1:58
+          _2 = move _3 as i32 (Misc);      // scope 0 at $DIR/issue-101973.rs:+1:5: +1:65
+          StorageDead(_3);                 // scope 0 at $DIR/issue-101973.rs:+1:64: +1:65
+          _0 = move _2 as i64 (Misc);      // scope 0 at $DIR/issue-101973.rs:+1:5: +1:72
+          StorageDead(_2);                 // scope 0 at $DIR/issue-101973.rs:+1:71: +1:72
+          return;                          // scope 0 at $DIR/issue-101973.rs:+2:2: +2:2
+      }
+  }
+  
diff --git a/src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.64bit.mir b/src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.64bit.mir
deleted file mode 100644
index 047b24db4664..000000000000
--- a/src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.64bit.mir
+++ /dev/null
@@ -1,20 +0,0 @@
-// MIR for `<impl at $DIR/issue-41697.rs:18:1: 18:23>::{constant#0}` after SimplifyCfg-promote-consts
-
-<impl at $DIR/issue-41697.rs:18:1: 18:23>::{constant#0}: usize = {
-    let mut _0: usize;                   // return place in scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-    let mut _1: (usize, bool);           // in scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-
-    bb0: {
-        _1 = CheckedAdd(const 1_usize, const 1_usize); // scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-        assert(!move (_1.1: bool), "attempt to compute `{} + {}`, which would overflow", const 1_usize, const 1_usize) -> [success: bb1, unwind: bb2]; // scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-    }
-
-    bb1: {
-        _0 = move (_1.0: usize);         // scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-        return;                          // scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-    }
-
-    bb2 (cleanup): {
-        resume;                          // scope 0 at $DIR/issue-41697.rs:+0:19: +0:22
-    }
-}
diff --git a/src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.32bit.mir b/src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.mir
similarity index 100%
rename from src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.32bit.mir
rename to src/test/mir-opt/issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.mir
diff --git a/src/test/mir-opt/issue_72181.bar.mir_map.0.64bit.mir b/src/test/mir-opt/issue_72181.bar.mir_map.0.64bit.mir
deleted file mode 100644
index 972ce1d50785..000000000000
--- a/src/test/mir-opt/issue_72181.bar.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,17 +0,0 @@
-// MIR for `bar` 0 mir_map
-
-fn bar(_1: [(Never, u32); 1]) -> u32 {
-    let mut _0: u32;                     // return place in scope 0 at $DIR/issue-72181.rs:+0:40: +0:43
-    let _2: u32;                         // in scope 0 at $DIR/issue-72181.rs:+0:13: +0:14
-    scope 1 {
-        debug x => _2;                   // in scope 1 at $DIR/issue-72181.rs:+0:13: +0:14
-    }
-
-    bb0: {
-        StorageLive(_2);                 // scope 0 at $DIR/issue-72181.rs:+0:13: +0:14
-        _2 = (_1[0 of 1].1: u32);        // scope 0 at $DIR/issue-72181.rs:+0:13: +0:14
-        _0 = _2;                         // scope 1 at $DIR/issue-72181.rs:+0:46: +0:47
-        StorageDead(_2);                 // scope 0 at $DIR/issue-72181.rs:+0:48: +0:49
-        return;                          // scope 0 at $DIR/issue-72181.rs:+0:49: +0:49
-    }
-}
diff --git a/src/test/mir-opt/issue_72181.bar.mir_map.0.32bit.mir b/src/test/mir-opt/issue_72181.bar.mir_map.0.mir
similarity index 100%
rename from src/test/mir-opt/issue_72181.bar.mir_map.0.32bit.mir
rename to src/test/mir-opt/issue_72181.bar.mir_map.0.mir
diff --git a/src/test/mir-opt/issue_72181.foo.mir_map.0.64bit.mir b/src/test/mir-opt/issue_72181.foo.mir_map.0.64bit.mir
deleted file mode 100644
index 534f131ea936..000000000000
--- a/src/test/mir-opt/issue_72181.foo.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,27 +0,0 @@
-// MIR for `foo` 0 mir_map
-
-fn foo(_1: [(Never, u32); 1]) -> u32 {
-    debug xs => _1;                      // in scope 0 at $DIR/issue-72181.rs:+0:8: +0:10
-    let mut _0: u32;                     // return place in scope 0 at $DIR/issue-72181.rs:+0:34: +0:37
-    let _2: usize;                       // in scope 0 at $DIR/issue-72181.rs:+0:43: +0:44
-    let mut _3: usize;                   // in scope 0 at $DIR/issue-72181.rs:+0:40: +0:45
-    let mut _4: bool;                    // in scope 0 at $DIR/issue-72181.rs:+0:40: +0:45
-
-    bb0: {
-        StorageLive(_2);                 // scope 0 at $DIR/issue-72181.rs:+0:43: +0:44
-        _2 = const 0_usize;              // scope 0 at $DIR/issue-72181.rs:+0:43: +0:44
-        _3 = Len(_1);                    // scope 0 at $DIR/issue-72181.rs:+0:40: +0:45
-        _4 = Lt(_2, _3);                 // scope 0 at $DIR/issue-72181.rs:+0:40: +0:45
-        assert(move _4, "index out of bounds: the length is {} but the index is {}", move _3, _2) -> [success: bb1, unwind: bb2]; // scope 0 at $DIR/issue-72181.rs:+0:40: +0:45
-    }
-
-    bb1: {
-        _0 = (_1[_2].1: u32);            // scope 0 at $DIR/issue-72181.rs:+0:40: +0:47
-        StorageDead(_2);                 // scope 0 at $DIR/issue-72181.rs:+0:48: +0:49
-        return;                          // scope 0 at $DIR/issue-72181.rs:+0:49: +0:49
-    }
-
-    bb2 (cleanup): {
-        resume;                          // scope 0 at $DIR/issue-72181.rs:+0:1: +0:49
-    }
-}
diff --git a/src/test/mir-opt/issue_72181.foo.mir_map.0.32bit.mir b/src/test/mir-opt/issue_72181.foo.mir_map.0.mir
similarity index 100%
rename from src/test/mir-opt/issue_72181.foo.mir_map.0.32bit.mir
rename to src/test/mir-opt/issue_72181.foo.mir_map.0.mir
diff --git a/src/test/mir-opt/issue_72181.main.mir_map.0.64bit.mir b/src/test/mir-opt/issue_72181.main.mir_map.0.64bit.mir
deleted file mode 100644
index 425906f84fcd..000000000000
--- a/src/test/mir-opt/issue_72181.main.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,62 +0,0 @@
-// MIR for `main` 0 mir_map
-
-fn main() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/issue-72181.rs:+0:11: +0:11
-    let mut _1: usize;                   // in scope 0 at $DIR/issue-72181.rs:+1:13: +1:34
-    let mut _3: Foo;                     // in scope 0 at $DIR/issue-72181.rs:+3:14: +3:27
-    let mut _4: Foo;                     // in scope 0 at $DIR/issue-72181.rs:+3:29: +3:42
-    let mut _5: u64;                     // in scope 0 at $DIR/issue-72181.rs:+4:13: +4:30
-    let _6: usize;                       // in scope 0 at $DIR/issue-72181.rs:+4:24: +4:25
-    let mut _7: usize;                   // in scope 0 at $DIR/issue-72181.rs:+4:22: +4:26
-    let mut _8: bool;                    // in scope 0 at $DIR/issue-72181.rs:+4:22: +4:26
-    scope 1 {
-        let _2: [Foo; 2];                // in scope 1 at $DIR/issue-72181.rs:+3:9: +3:10
-        scope 2 {
-            debug f => _2;               // in scope 2 at $DIR/issue-72181.rs:+3:9: +3:10
-            scope 3 {
-            }
-            scope 4 {
-            }
-        }
-    }
-
-    bb0: {
-        StorageLive(_1);                 // scope 0 at $DIR/issue-72181.rs:+1:13: +1:34
-        _1 = std::mem::size_of::<Foo>() -> [return: bb1, unwind: bb3]; // scope 0 at $DIR/issue-72181.rs:+1:13: +1:34
-                                         // mir::Constant
-                                         // + span: $DIR/issue-72181.rs:24:13: 24:32
-                                         // + literal: Const { ty: fn() -> usize {std::mem::size_of::<Foo>}, val: Value(<ZST>) }
-    }
-
-    bb1: {
-        StorageDead(_1);                 // scope 0 at $DIR/issue-72181.rs:+1:34: +1:35
-        StorageLive(_2);                 // scope 1 at $DIR/issue-72181.rs:+3:9: +3:10
-        StorageLive(_3);                 // scope 1 at $DIR/issue-72181.rs:+3:14: +3:27
-        _3 = Foo { a: const 42_u64 };    // scope 1 at $DIR/issue-72181.rs:+3:14: +3:27
-        StorageLive(_4);                 // scope 1 at $DIR/issue-72181.rs:+3:29: +3:42
-        _4 = Foo { a: const 10_u64 };    // scope 1 at $DIR/issue-72181.rs:+3:29: +3:42
-        _2 = [move _3, move _4];         // scope 1 at $DIR/issue-72181.rs:+3:13: +3:43
-        StorageDead(_4);                 // scope 1 at $DIR/issue-72181.rs:+3:42: +3:43
-        StorageDead(_3);                 // scope 1 at $DIR/issue-72181.rs:+3:42: +3:43
-        FakeRead(ForLet(None), _2);      // scope 1 at $DIR/issue-72181.rs:+3:9: +3:10
-        StorageLive(_5);                 // scope 2 at $DIR/issue-72181.rs:+4:13: +4:30
-        StorageLive(_6);                 // scope 4 at $DIR/issue-72181.rs:+4:24: +4:25
-        _6 = const 0_usize;              // scope 4 at $DIR/issue-72181.rs:+4:24: +4:25
-        _7 = Len(_2);                    // scope 4 at $DIR/issue-72181.rs:+4:22: +4:26
-        _8 = Lt(_6, _7);                 // scope 4 at $DIR/issue-72181.rs:+4:22: +4:26
-        assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> [success: bb2, unwind: bb3]; // scope 4 at $DIR/issue-72181.rs:+4:22: +4:26
-    }
-
-    bb2: {
-        _5 = (_2[_6].0: u64);            // scope 4 at $DIR/issue-72181.rs:+4:22: +4:28
-        StorageDead(_6);                 // scope 2 at $DIR/issue-72181.rs:+4:30: +4:31
-        StorageDead(_5);                 // scope 2 at $DIR/issue-72181.rs:+4:30: +4:31
-        _0 = const ();                   // scope 0 at $DIR/issue-72181.rs:+0:11: +5:2
-        StorageDead(_2);                 // scope 1 at $DIR/issue-72181.rs:+5:1: +5:2
-        return;                          // scope 0 at $DIR/issue-72181.rs:+5:2: +5:2
-    }
-
-    bb3 (cleanup): {
-        resume;                          // scope 0 at $DIR/issue-72181.rs:+0:1: +5:2
-    }
-}
diff --git a/src/test/mir-opt/issue_72181.main.mir_map.0.32bit.mir b/src/test/mir-opt/issue_72181.main.mir_map.0.mir
similarity index 100%
rename from src/test/mir-opt/issue_72181.main.mir_map.0.32bit.mir
rename to src/test/mir-opt/issue_72181.main.mir_map.0.mir
diff --git a/src/test/mir-opt/issue_73223.main.PreCodegen.32bit.diff b/src/test/mir-opt/issue_73223.main.PreCodegen.32bit.diff
deleted file mode 100644
index be8e86a832cb..000000000000
--- a/src/test/mir-opt/issue_73223.main.PreCodegen.32bit.diff
+++ /dev/null
@@ -1,117 +0,0 @@
-- // MIR for `main` before PreCodegen
-+ // MIR for `main` after PreCodegen
-  
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/issue-73223.rs:+0:11: +0:11
-      let _1: i32;                         // in scope 0 at $DIR/issue-73223.rs:+1:9: +1:14
-      let mut _2: std::option::Option<i32>; // in scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-      let _3: i32;                         // in scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-      let mut _5: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _6: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _7: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _10: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _11: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _12: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _14: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _15: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _16: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _17: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _18: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _19: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      scope 1 {
-          debug split => _1;               // in scope 1 at $DIR/issue-73223.rs:+1:9: +1:14
-          let _4: std::option::Option<i32>; // in scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
-          scope 3 {
-              debug _prev => _4;           // in scope 3 at $DIR/issue-73223.rs:+6:9: +6:14
-              let _8: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let _9: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let mut _20: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              scope 4 {
-                  debug left_val => _8;    // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  debug right_val => _9;   // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  let _13: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  scope 5 {
-                      debug kind => _13;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  }
-              }
-          }
-      }
-      scope 2 {
-          debug v => _3;                   // in scope 2 at $DIR/issue-73223.rs:+2:14: +2:15
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/issue-73223.rs:+1:9: +1:14
-          StorageLive(_2);                 // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          Deinit(_2);                      // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          ((_2 as Some).0: i32) = const 1_i32; // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          discriminant(_2) = 1;            // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          StorageLive(_3);                 // scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-          _3 = ((_2 as Some).0: i32);      // scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-          _1 = _3;                         // scope 2 at $DIR/issue-73223.rs:+2:20: +2:21
-          StorageDead(_3);                 // scope 0 at $DIR/issue-73223.rs:+2:20: +2:21
-          StorageDead(_2);                 // scope 0 at $DIR/issue-73223.rs:+4:6: +4:7
-          StorageLive(_4);                 // scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
-          StorageLive(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _6 = &_1;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _20 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
-          _7 = _20;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_5);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_5.0: &i32) = move _6;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_5.1: &i32) = move _7;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _8 = (_5.0: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _9 = (_5.1: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _12 = (*_8);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _11 = Eq(move _12, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _10 = Not(move _11);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          switchInt(move _10) -> [false: bb2, otherwise: bb1]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      }
-  
-      bb1: {
-          StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_14);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_15);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_16);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _16 = _8;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _15 = _16;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_17);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_18);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _18 = _9;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _17 = _18;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_19);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_19);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_19) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _14 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _15, move _17, move _19); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r i32, &'s i32, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(<ZST>) }
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: core::panicking::AssertKind, val: Value(Scalar(0x00)) }
-      }
-  
-      bb2: {
-          StorageDead(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_4);                 // scope 1 at $DIR/issue-73223.rs:+8:1: +8:2
-          StorageDead(_1);                 // scope 0 at $DIR/issue-73223.rs:+8:1: +8:2
-          return;                          // scope 0 at $DIR/issue-73223.rs:+8:2: +8:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/issue_73223.main.PreCodegen.64bit.diff b/src/test/mir-opt/issue_73223.main.PreCodegen.64bit.diff
deleted file mode 100644
index be8e86a832cb..000000000000
--- a/src/test/mir-opt/issue_73223.main.PreCodegen.64bit.diff
+++ /dev/null
@@ -1,117 +0,0 @@
-- // MIR for `main` before PreCodegen
-+ // MIR for `main` after PreCodegen
-  
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/issue-73223.rs:+0:11: +0:11
-      let _1: i32;                         // in scope 0 at $DIR/issue-73223.rs:+1:9: +1:14
-      let mut _2: std::option::Option<i32>; // in scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-      let _3: i32;                         // in scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-      let mut _5: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _6: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _7: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _10: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _11: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _12: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _14: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _15: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _16: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _17: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _18: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _19: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      scope 1 {
-          debug split => _1;               // in scope 1 at $DIR/issue-73223.rs:+1:9: +1:14
-          let _4: std::option::Option<i32>; // in scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
-          scope 3 {
-              debug _prev => _4;           // in scope 3 at $DIR/issue-73223.rs:+6:9: +6:14
-              let _8: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let _9: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let mut _20: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              scope 4 {
-                  debug left_val => _8;    // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  debug right_val => _9;   // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  let _13: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  scope 5 {
-                      debug kind => _13;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  }
-              }
-          }
-      }
-      scope 2 {
-          debug v => _3;                   // in scope 2 at $DIR/issue-73223.rs:+2:14: +2:15
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/issue-73223.rs:+1:9: +1:14
-          StorageLive(_2);                 // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          Deinit(_2);                      // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          ((_2 as Some).0: i32) = const 1_i32; // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          discriminant(_2) = 1;            // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          StorageLive(_3);                 // scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-          _3 = ((_2 as Some).0: i32);      // scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-          _1 = _3;                         // scope 2 at $DIR/issue-73223.rs:+2:20: +2:21
-          StorageDead(_3);                 // scope 0 at $DIR/issue-73223.rs:+2:20: +2:21
-          StorageDead(_2);                 // scope 0 at $DIR/issue-73223.rs:+4:6: +4:7
-          StorageLive(_4);                 // scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
-          StorageLive(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _6 = &_1;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _20 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
-          _7 = _20;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_5);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_5.0: &i32) = move _6;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_5.1: &i32) = move _7;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _8 = (_5.0: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _9 = (_5.1: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _12 = (*_8);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _11 = Eq(move _12, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _10 = Not(move _11);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          switchInt(move _10) -> [false: bb2, otherwise: bb1]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      }
-  
-      bb1: {
-          StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_14);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_15);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_16);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _16 = _8;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _15 = _16;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_17);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_18);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _18 = _9;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _17 = _18;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_19);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_19);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_19) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _14 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _15, move _17, move _19); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r i32, &'s i32, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(<ZST>) }
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: core::panicking::AssertKind, val: Value(Scalar(0x00)) }
-      }
-  
-      bb2: {
-          StorageDead(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_4);                 // scope 1 at $DIR/issue-73223.rs:+8:1: +8:2
-          StorageDead(_1);                 // scope 0 at $DIR/issue-73223.rs:+8:1: +8:2
-          return;                          // scope 0 at $DIR/issue-73223.rs:+8:2: +8:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.32bit.diff b/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.32bit.diff
deleted file mode 100644
index ac7fe31f3b39..000000000000
--- a/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.32bit.diff
+++ /dev/null
@@ -1,161 +0,0 @@
-- // MIR for `main` before SimplifyArmIdentity
-+ // MIR for `main` after SimplifyArmIdentity
-  
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/issue-73223.rs:+0:11: +0:11
-      let _1: i32;                         // in scope 0 at $DIR/issue-73223.rs:+1:9: +1:14
-      let mut _2: std::option::Option<i32>; // in scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-      let mut _3: isize;                   // in scope 0 at $DIR/issue-73223.rs:+2:9: +2:16
-      let _4: i32;                         // in scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-      let mut _5: !;                       // in scope 0 at $DIR/issue-73223.rs:+3:17: +3:23
-      let mut _7: i32;                     // in scope 0 at $DIR/issue-73223.rs:+6:22: +6:27
-      let _8: ();                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _9: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _10: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _11: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _12: i32;                        // in scope 0 at $DIR/issue-73223.rs:+7:23: +7:24
-      let mut _15: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _16: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _17: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _18: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _19: !;                      // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _21: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _22: core::panicking::AssertKind; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _23: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _24: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _25: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _26: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _27: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      scope 1 {
-          debug split => _1;               // in scope 1 at $DIR/issue-73223.rs:+1:9: +1:14
-          let _6: std::option::Option<i32>; // in scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
-          scope 3 {
-              debug _prev => _6;           // in scope 3 at $DIR/issue-73223.rs:+6:9: +6:14
-              let _13: &i32;               // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let _14: &i32;               // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let mut _28: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              scope 4 {
-                  debug left_val => _13;   // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  debug right_val => _14;  // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  let _20: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  scope 5 {
-                      debug kind => _20;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  }
-              }
-          }
-      }
-      scope 2 {
-          debug v => _4;                   // in scope 2 at $DIR/issue-73223.rs:+2:14: +2:15
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/issue-73223.rs:+1:9: +1:14
-          StorageLive(_2);                 // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          Deinit(_2);                      // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          ((_2 as Some).0: i32) = const 1_i32; // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          discriminant(_2) = 1;            // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          _3 = const 1_isize;              // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-          goto -> bb3;                     // scope 0 at $DIR/issue-73223.rs:+1:17: +1:30
-      }
-  
-      bb1: {
-          nop;                             // scope 0 at $DIR/issue-73223.rs:+3:17: +3:23
-          StorageDead(_2);                 // scope 0 at $DIR/issue-73223.rs:+4:6: +4:7
-          StorageDead(_1);                 // scope 0 at $DIR/issue-73223.rs:+8:1: +8:2
-          return;                          // scope 0 at $DIR/issue-73223.rs:+8:2: +8:2
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/issue-73223.rs:+1:23: +1:30
-      }
-  
-      bb3: {
-          StorageLive(_4);                 // scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-          _4 = ((_2 as Some).0: i32);      // scope 0 at $DIR/issue-73223.rs:+2:14: +2:15
-          _1 = _4;                         // scope 2 at $DIR/issue-73223.rs:+2:20: +2:21
-          StorageDead(_4);                 // scope 0 at $DIR/issue-73223.rs:+2:20: +2:21
-          StorageDead(_2);                 // scope 0 at $DIR/issue-73223.rs:+4:6: +4:7
-          StorageLive(_6);                 // scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
-          StorageLive(_7);                 // scope 1 at $DIR/issue-73223.rs:+6:22: +6:27
-          _7 = _1;                         // scope 1 at $DIR/issue-73223.rs:+6:22: +6:27
-          Deinit(_6);                      // scope 1 at $DIR/issue-73223.rs:+6:17: +6:28
-          ((_6 as Some).0: i32) = move _7; // scope 1 at $DIR/issue-73223.rs:+6:17: +6:28
-          discriminant(_6) = 1;            // scope 1 at $DIR/issue-73223.rs:+6:17: +6:28
-          StorageDead(_7);                 // scope 1 at $DIR/issue-73223.rs:+6:27: +6:28
-          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _10 = &_1;                       // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_11);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _28 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
-          _11 = _28;                       // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_9);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_9.0: &i32) = move _10;         // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_9.1: &i32) = move _11;         // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_11);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_13);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _13 = (_9.0: &i32);              // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_14);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _14 = (_9.1: &i32);              // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_15);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_16);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_17);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _17 = (*_13);                    // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_18);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _18 = const 1_i32;               // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _16 = Eq(move _17, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_18);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_17);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _15 = Not(move _16);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_16);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          switchInt(move _15) -> [false: bb5, otherwise: bb4]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      }
-  
-      bb4: {
-          StorageLive(_20);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_20);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_20) = 0;           // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_21);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_22);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _22 = const core::panicking::AssertKind::Eq; // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: core::panicking::AssertKind, val: Value(Scalar(0x00)) }
-          StorageLive(_23);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_24);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _24 = _13;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _23 = _24;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_25);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_26);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _26 = _14;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _25 = _26;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_27);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_27);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_27) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _21 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _23, move _25, move _27); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r i32, &'s i32, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(<ZST>) }
-                                           // mir::Constant
-                                           // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: core::panicking::AssertKind, val: Value(Scalar(0x00)) }
-      }
-  
-      bb5: {
-          nop;                             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_15);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_14);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_13);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          nop;                             // scope 0 at $DIR/issue-73223.rs:+0:11: +8:2
-          StorageDead(_6);                 // scope 1 at $DIR/issue-73223.rs:+8:1: +8:2
-          StorageDead(_1);                 // scope 0 at $DIR/issue-73223.rs:+8:1: +8:2
-          return;                          // scope 0 at $DIR/issue-73223.rs:+8:2: +8:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.64bit.diff b/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.diff
similarity index 97%
rename from src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.64bit.diff
rename to src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.diff
index ac7fe31f3b39..269e4e326175 100644
--- a/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.64bit.diff
+++ b/src/test/mir-opt/issue_73223.main.SimplifyArmIdentity.diff
@@ -25,7 +25,7 @@
       let _24: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       let mut _25: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       let _26: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _27: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _27: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       scope 1 {
           debug split => _1;               // in scope 1 at $DIR/issue-73223.rs:+1:9: +1:14
           let _6: std::option::Option<i32>; // in scope 1 at $DIR/issue-73223.rs:+6:9: +6:14
@@ -87,7 +87,7 @@
           StorageLive(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           _10 = &_1;                       // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_11);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _28 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _28 = const _;                   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
@@ -139,7 +139,7 @@
           _21 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _23, move _25, move _27); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                           // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r i32, &'s i32, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a i32, &'b i32, Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(<ZST>) }
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // + literal: Const { ty: core::panicking::AssertKind, val: Value(Scalar(0x00)) }
diff --git a/src/test/mir-opt/issue_91633.bar.mir_map.0.mir b/src/test/mir-opt/issue_91633.bar.mir_map.0.mir
index f5092d2ac923..625f6c7361ac 100644
--- a/src/test/mir-opt/issue_91633.bar.mir_map.0.mir
+++ b/src/test/mir-opt/issue_91633.bar.mir_map.0.mir
@@ -15,7 +15,7 @@ fn bar(_1: Box<[T]>) -> () {
         _2 = <[T] as Index<usize>>::index(move _3, const 0_usize) -> [return: bb1, unwind: bb3]; // scope 0 at $DIR/issue-91633.rs:+4:14: +4:19
                                          // mir::Constant
                                          // + span: $DIR/issue-91633.rs:15:14: 15:19
-                                         // + literal: Const { ty: for<'r> fn(&'r [T], usize) -> &'r <[T] as Index<usize>>::Output {<[T] as Index<usize>>::index}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a [T], usize) -> &'a <[T] as Index<usize>>::Output {<[T] as Index<usize>>::index}, val: Value(<ZST>) }
     }
 
     bb1: {
diff --git a/src/test/mir-opt/issue_91633.foo.mir_map.0.mir b/src/test/mir-opt/issue_91633.foo.mir_map.0.mir
index 2e8b0feedd3f..9903e203a231 100644
--- a/src/test/mir-opt/issue_91633.foo.mir_map.0.mir
+++ b/src/test/mir-opt/issue_91633.foo.mir_map.0.mir
@@ -27,7 +27,7 @@ fn foo(_1: Box<[T]>) -> T {
         _2 = <T as Clone>::clone(move _3) -> [return: bb2, unwind: bb5]; // scope 0 at $DIR/issue-91633.rs:+2:14: +2:27
                                          // mir::Constant
                                          // + span: $DIR/issue-91633.rs:28:20: 28:25
-                                         // + literal: Const { ty: for<'r> fn(&'r T) -> T {<T as Clone>::clone}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a T) -> T {<T as Clone>::clone}, val: Value(<ZST>) }
     }
 
     bb2: {
diff --git a/src/test/mir-opt/issue_91633.hey.mir_map.0.mir b/src/test/mir-opt/issue_91633.hey.mir_map.0.mir
index 74f4a5a97611..37c3b3fcacaf 100644
--- a/src/test/mir-opt/issue_91633.hey.mir_map.0.mir
+++ b/src/test/mir-opt/issue_91633.hey.mir_map.0.mir
@@ -17,7 +17,7 @@ fn hey(_1: &[T]) -> () {
         _3 = <[T] as Index<usize>>::index(move _4, const 0_usize) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/issue-91633.rs:+4:15: +4:20
                                          // mir::Constant
                                          // + span: $DIR/issue-91633.rs:7:15: 7:20
-                                         // + literal: Const { ty: for<'r> fn(&'r [T], usize) -> &'r <[T] as Index<usize>>::Output {<[T] as Index<usize>>::index}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a [T], usize) -> &'a <[T] as Index<usize>>::Output {<[T] as Index<usize>>::index}, val: Value(<ZST>) }
     }
 
     bb1: {
diff --git a/src/test/mir-opt/issue_99325.main.mir_map.0.mir b/src/test/mir-opt/issue_99325.main.mir_map.0.mir
index 5bca9f0ea989..165efa9df411 100644
--- a/src/test/mir-opt/issue_99325.main.mir_map.0.mir
+++ b/src/test/mir-opt/issue_99325.main.mir_map.0.mir
@@ -2,7 +2,7 @@
 
 | User Type Annotations
 | 0: user_ty: Canonical { max_universe: U0, variables: [], value: TypeOf(DefId(0:3 ~ issue_99325[8f58]::function_with_bytes), UserSubsts { substs: [Const { ty: &'static [u8; 4], kind: Value(Branch([Leaf(0x41), Leaf(0x41), Leaf(0x41), Leaf(0x41)])) }], user_self_ty: None }) }, span: $DIR/issue-99325.rs:10:16: 10:46, inferred_ty: fn() -> &'static [u8] {function_with_bytes::<&*b"AAAA">}
-| 1: user_ty: Canonical { max_universe: U0, variables: [], value: TypeOf(DefId(0:3 ~ issue_99325[8f58]::function_with_bytes), UserSubsts { substs: [Const { ty: &'static [u8; 4], kind: Unevaluated(Unevaluated { def: WithOptConstParam { did: DefId(0:8 ~ issue_99325[8f58]::main::{constant#1}), const_param_did: Some(DefId(0:4 ~ issue_99325[8f58]::function_with_bytes::BYTES)) }, substs: [], promoted: None }) }], user_self_ty: None }) }, span: $DIR/issue-99325.rs:11:16: 11:68, inferred_ty: fn() -> &'static [u8] {function_with_bytes::<&*b"AAAA">}
+| 1: user_ty: Canonical { max_universe: U0, variables: [], value: TypeOf(DefId(0:3 ~ issue_99325[8f58]::function_with_bytes), UserSubsts { substs: [Const { ty: &'static [u8; 4], kind: Unevaluated(UnevaluatedConst { def: WithOptConstParam { did: DefId(0:8 ~ issue_99325[8f58]::main::{constant#1}), const_param_did: Some(DefId(0:4 ~ issue_99325[8f58]::function_with_bytes::BYTES)) }, substs: [] }) }], user_self_ty: None }) }, span: $DIR/issue-99325.rs:11:16: 11:68, inferred_ty: fn() -> &'static [u8] {function_with_bytes::<&*b"AAAA">}
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/issue-99325.rs:+0:15: +0:15
@@ -26,7 +26,7 @@ fn main() -> () {
     let _19: &&[u8];                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _20: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let _21: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _22: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _22: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let _23: ();                         // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _24: (&&[u8], &&[u8; 4]);    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _25: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
@@ -46,7 +46,7 @@ fn main() -> () {
     let _40: &&[u8];                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _41: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let _42: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _43: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _43: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     scope 1 {
         debug left_val => _8;            // in scope 1 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         debug right_val => _9;           // in scope 1 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
@@ -101,7 +101,7 @@ fn main() -> () {
         _11 = <&[u8] as PartialEq<&[u8; 4]>>::eq(move _12, move _13) -> [return: bb2, unwind: bb19]; // scope 1 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r, 's> fn(&'r &[u8], &'s &[u8; 4]) -> bool {<&[u8] as PartialEq<&[u8; 4]>>::eq}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b> fn(&'a &[u8], &'b &[u8; 4]) -> bool {<&[u8] as PartialEq<&[u8; 4]>>::eq}, val: Value(<ZST>) }
     }
 
     bb2: {
@@ -128,11 +128,11 @@ fn main() -> () {
         _21 = &(*_9);                    // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _20 = &(*_21);                   // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_22);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _22 = Option::<Arguments>::None; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _22 = Option::<Arguments<'_>>::None; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _16 = core::panicking::assert_failed::<&[u8], &[u8; 4]>(move _17, move _18, move _20, move _22) -> bb19; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r &[u8], &'s &[u8; 4], Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a &[u8], &'b &[u8; 4], Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
     }
 
     bb4: {
@@ -210,7 +210,7 @@ fn main() -> () {
         _32 = <&[u8] as PartialEq<&[u8; 4]>>::eq(move _33, move _34) -> [return: bb11, unwind: bb19]; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r, 's> fn(&'r &[u8], &'s &[u8; 4]) -> bool {<&[u8] as PartialEq<&[u8; 4]>>::eq}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b> fn(&'a &[u8], &'b &[u8; 4]) -> bool {<&[u8] as PartialEq<&[u8; 4]>>::eq}, val: Value(<ZST>) }
     }
 
     bb11: {
@@ -237,11 +237,11 @@ fn main() -> () {
         _42 = &(*_30);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _41 = &(*_42);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_43);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _43 = Option::<Arguments>::None; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _43 = Option::<Arguments<'_>>::None; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _37 = core::panicking::assert_failed::<&[u8], &[u8; 4]>(move _38, move _39, move _41, move _43) -> bb19; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r &[u8], &'s &[u8; 4], Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a &[u8], &'b &[u8; 4], Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
     }
 
     bb13: {
diff --git a/src/test/mir-opt/lower_array_len.array_bound.InstCombine.diff b/src/test/mir-opt/lower_array_len.array_bound.InstCombine.diff
deleted file mode 100644
index 2589c9f282f3..000000000000
--- a/src/test/mir-opt/lower_array_len.array_bound.InstCombine.diff
+++ /dev/null
@@ -1,66 +0,0 @@
-- // MIR for `array_bound` before InstCombine
-+ // MIR for `array_bound` after InstCombine
-  
-  fn array_bound(_1: usize, _2: &[u8; N]) -> u8 {
-      debug index => _1;                   // in scope 0 at $DIR/lower_array_len.rs:+0:36: +0:41
-      debug slice => _2;                   // in scope 0 at $DIR/lower_array_len.rs:+0:50: +0:55
-      let mut _0: u8;                      // return place in scope 0 at $DIR/lower_array_len.rs:+0:70: +0:72
-      let mut _3: bool;                    // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      let mut _4: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-      let mut _5: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-      let mut _6: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-      let mut _7: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-      let _8: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-      let mut _9: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      let mut _10: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      let mut _11: &[u8; N];               // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-  
-      bb0: {
-          StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          _4 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          StorageLive(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageLive(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         _7 = &(*_2);                     // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-+         _7 = _2;                         // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageLive(_11);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          _11 = _7;                        // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          _6 = move _7 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageDead(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:20: +1:21
--         _5 = Len((*_11));                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-+         _5 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageDead(_11);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageDead(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          _3 = Lt(move _4, move _5);       // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageDead(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          switchInt(move _3) -> [false: bb3, otherwise: bb1]; // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      }
-  
-      bb1: {
-          StorageLive(_8);                 // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-          _8 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--         _9 = Len((*_2));                 // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         _9 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-          _10 = Lt(_8, _9);                // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-          assert(move _10, "index out of bounds: the length is {} but the index is {}", move _9, _8) -> bb2; // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      }
-  
-      bb2: {
-          _0 = (*_2)[_8];                  // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-          StorageDead(_8);                 // scope 0 at $DIR/lower_array_len.rs:+3:5: +3:6
-          goto -> bb4;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +5:6
-      }
-  
-      bb3: {
-          _0 = const 42_u8;                // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:11
-          goto -> bb4;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +5:6
-      }
-  
-      bb4: {
-          StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+5:5: +5:6
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+6:2: +6:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_bound.SimplifyLocals.diff b/src/test/mir-opt/lower_array_len.array_bound.SimplifyLocals.diff
deleted file mode 100644
index 8312db6b37b3..000000000000
--- a/src/test/mir-opt/lower_array_len.array_bound.SimplifyLocals.diff
+++ /dev/null
@@ -1,70 +0,0 @@
-- // MIR for `array_bound` before SimplifyLocals
-+ // MIR for `array_bound` after SimplifyLocals
-  
-  fn array_bound(_1: usize, _2: &[u8; N]) -> u8 {
-      debug index => _1;                   // in scope 0 at $DIR/lower_array_len.rs:+0:36: +0:41
-      debug slice => _2;                   // in scope 0 at $DIR/lower_array_len.rs:+0:50: +0:55
-      let mut _0: u8;                      // return place in scope 0 at $DIR/lower_array_len.rs:+0:70: +0:72
-      let mut _3: bool;                    // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      let mut _4: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-      let mut _5: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--     let mut _6: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--     let mut _7: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--     let _8: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--     let mut _9: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--     let mut _10: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--     let mut _11: &[u8; N];               // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-+     let _6: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-+     let mut _7: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+     let mut _8: bool;                    // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-  
-      bb0: {
-          StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          _4 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          StorageLive(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageLive(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageLive(_11);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageDead(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:20: +1:21
-          _5 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageDead(_11);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageDead(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          _3 = Lt(move _4, move _5);       // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageDead(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          switchInt(move _3) -> [false: bb3, otherwise: bb1]; // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      }
-  
-      bb1: {
--         StorageLive(_8);                 // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--         _8 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--         _9 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--         _10 = Lt(_8, _9);                // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--         assert(move _10, "index out of bounds: the length is {} but the index is {}", move _9, _8) -> bb2; // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-+         _6 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-+         _7 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         _8 = Lt(_6, _7);                 // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb2; // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      }
-  
-      bb2: {
--         _0 = (*_2)[_8];                  // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--         StorageDead(_8);                 // scope 0 at $DIR/lower_array_len.rs:+3:5: +3:6
-+         _0 = (*_2)[_6];                  // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         StorageDead(_6);                 // scope 0 at $DIR/lower_array_len.rs:+3:5: +3:6
-          goto -> bb4;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +5:6
-      }
-  
-      bb3: {
-          _0 = const 42_u8;                // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:11
-          goto -> bb4;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +5:6
-      }
-  
-      bb4: {
-          StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+5:5: +5:6
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+6:2: +6:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_bound_mut.InstCombine.diff b/src/test/mir-opt/lower_array_len.array_bound_mut.InstCombine.diff
deleted file mode 100644
index 401d4bac61e0..000000000000
--- a/src/test/mir-opt/lower_array_len.array_bound_mut.InstCombine.diff
+++ /dev/null
@@ -1,79 +0,0 @@
-- // MIR for `array_bound_mut` before InstCombine
-+ // MIR for `array_bound_mut` after InstCombine
-  
-  fn array_bound_mut(_1: usize, _2: &mut [u8; N]) -> u8 {
-      debug index => _1;                   // in scope 0 at $DIR/lower_array_len.rs:+0:40: +0:45
-      debug slice => _2;                   // in scope 0 at $DIR/lower_array_len.rs:+0:54: +0:59
-      let mut _0: u8;                      // return place in scope 0 at $DIR/lower_array_len.rs:+0:78: +0:80
-      let mut _3: bool;                    // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      let mut _4: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-      let mut _5: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-      let mut _6: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-      let mut _7: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-      let _8: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-      let mut _9: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      let mut _10: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      let _11: usize;                      // in scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
-      let mut _12: usize;                  // in scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-      let mut _13: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-      let mut _14: &[u8; N];               // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-  
-      bb0: {
-          StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          _4 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          StorageLive(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageLive(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          _7 = &(*_2);                     // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageLive(_14);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          _14 = _7;                        // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          _6 = move _7 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageDead(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:20: +1:21
--         _5 = Len((*_14));                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-+         _5 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageDead(_14);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-          StorageDead(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          _3 = Lt(move _4, move _5);       // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageDead(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          switchInt(move _3) -> [false: bb3, otherwise: bb1]; // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      }
-  
-      bb1: {
-          StorageLive(_8);                 // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-          _8 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--         _9 = Len((*_2));                 // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         _9 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-          _10 = Lt(_8, _9);                // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-          assert(move _10, "index out of bounds: the length is {} but the index is {}", move _9, _8) -> bb2; // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      }
-  
-      bb2: {
-          _0 = (*_2)[_8];                  // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-          StorageDead(_8);                 // scope 0 at $DIR/lower_array_len.rs:+3:5: +3:6
-          goto -> bb5;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +7:6
-      }
-  
-      bb3: {
-          StorageLive(_11);                // scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
-          _11 = const 0_usize;             // scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
--         _12 = Len((*_2));                // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-+         _12 = const N;                   // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-          _13 = Lt(_11, _12);              // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-          assert(move _13, "index out of bounds: the length is {} but the index is {}", move _12, _11) -> bb4; // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-      }
-  
-      bb4: {
-          (*_2)[_11] = const 42_u8;        // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:22
-          StorageDead(_11);                // scope 0 at $DIR/lower_array_len.rs:+4:22: +4:23
-          _0 = const 42_u8;                // scope 0 at $DIR/lower_array_len.rs:+6:9: +6:11
-          goto -> bb5;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +7:6
-      }
-  
-      bb5: {
-          StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+7:5: +7:6
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+8:2: +8:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_bound_mut.SimplifyLocals.diff b/src/test/mir-opt/lower_array_len.array_bound_mut.SimplifyLocals.diff
deleted file mode 100644
index 4f241d7c9064..000000000000
--- a/src/test/mir-opt/lower_array_len.array_bound_mut.SimplifyLocals.diff
+++ /dev/null
@@ -1,93 +0,0 @@
-- // MIR for `array_bound_mut` before SimplifyLocals
-+ // MIR for `array_bound_mut` after SimplifyLocals
-  
-  fn array_bound_mut(_1: usize, _2: &mut [u8; N]) -> u8 {
-      debug index => _1;                   // in scope 0 at $DIR/lower_array_len.rs:+0:40: +0:45
-      debug slice => _2;                   // in scope 0 at $DIR/lower_array_len.rs:+0:54: +0:59
-      let mut _0: u8;                      // return place in scope 0 at $DIR/lower_array_len.rs:+0:78: +0:80
-      let mut _3: bool;                    // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      let mut _4: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-      let mut _5: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--     let mut _6: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--     let mut _7: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--     let _8: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--     let mut _9: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--     let mut _10: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--     let _11: usize;                      // in scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
--     let mut _12: usize;                  // in scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
--     let mut _13: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
--     let mut _14: &[u8; N];               // in scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
-+     let _6: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-+     let mut _7: usize;                   // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+     let mut _8: bool;                    // in scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+     let _9: usize;                       // in scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
-+     let mut _10: usize;                  // in scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-+     let mut _11: bool;                   // in scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-  
-      bb0: {
-          StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          _4 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:13
-          StorageLive(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageLive(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageLive(_14);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageDead(_7);                 // scope 0 at $DIR/lower_array_len.rs:+1:20: +1:21
-          _5 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageDead(_14);                // scope 0 at $DIR/lower_array_len.rs:+1:16: +1:27
--         StorageDead(_6);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          _3 = Lt(move _4, move _5);       // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-          StorageDead(_5);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:26: +1:27
-          switchInt(move _3) -> [false: bb3, otherwise: bb1]; // scope 0 at $DIR/lower_array_len.rs:+1:8: +1:27
-      }
-  
-      bb1: {
--         StorageLive(_8);                 // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--         _8 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
--         _9 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--         _10 = Lt(_8, _9);                // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--         assert(move _10, "index out of bounds: the length is {} but the index is {}", move _9, _8) -> bb2; // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-+         _6 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+2:15: +2:20
-+         _7 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         _8 = Lt(_6, _7);                 // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb2; // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-      }
-  
-      bb2: {
--         _0 = (*_2)[_8];                  // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
--         StorageDead(_8);                 // scope 0 at $DIR/lower_array_len.rs:+3:5: +3:6
-+         _0 = (*_2)[_6];                  // scope 0 at $DIR/lower_array_len.rs:+2:9: +2:21
-+         StorageDead(_6);                 // scope 0 at $DIR/lower_array_len.rs:+3:5: +3:6
-          goto -> bb5;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +7:6
-      }
-  
-      bb3: {
--         StorageLive(_11);                // scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
--         _11 = const 0_usize;             // scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
--         _12 = const N;                   // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
--         _13 = Lt(const 0_usize, _12);    // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
--         assert(move _13, "index out of bounds: the length is {} but the index is {}", move _12, const 0_usize) -> bb4; // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-+         StorageLive(_9);                 // scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
-+         _9 = const 0_usize;              // scope 0 at $DIR/lower_array_len.rs:+4:15: +4:16
-+         _10 = const N;                   // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-+         _11 = Lt(const 0_usize, _10);    // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-+         assert(move _11, "index out of bounds: the length is {} but the index is {}", move _10, const 0_usize) -> bb4; // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:17
-      }
-  
-      bb4: {
--         (*_2)[_11] = const 42_u8;        // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:22
--         StorageDead(_11);                // scope 0 at $DIR/lower_array_len.rs:+4:22: +4:23
-+         (*_2)[_9] = const 42_u8;         // scope 0 at $DIR/lower_array_len.rs:+4:9: +4:22
-+         StorageDead(_9);                 // scope 0 at $DIR/lower_array_len.rs:+4:22: +4:23
-          _0 = const 42_u8;                // scope 0 at $DIR/lower_array_len.rs:+6:9: +6:11
-          goto -> bb5;                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +7:6
-      }
-  
-      bb5: {
-          StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+7:5: +7:6
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+8:2: +8:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_len.InstCombine.diff b/src/test/mir-opt/lower_array_len.array_len.InstCombine.diff
deleted file mode 100644
index 26f45be17be6..000000000000
--- a/src/test/mir-opt/lower_array_len.array_len.InstCombine.diff
+++ /dev/null
@@ -1,27 +0,0 @@
-- // MIR for `array_len` before InstCombine
-+ // MIR for `array_len` after InstCombine
-  
-  fn array_len(_1: &[u8; N]) -> usize {
-      debug arr => _1;                     // in scope 0 at $DIR/lower_array_len.rs:+0:34: +0:37
-      let mut _0: usize;                   // return place in scope 0 at $DIR/lower_array_len.rs:+0:52: +0:57
-      let mut _2: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-      let mut _3: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-      let mut _4: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-  
-      bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         _3 = &(*_1);                     // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-+         _3 = _1;                         // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          _4 = _3;                         // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          _2 = move _3 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:7: +1:8
--         _0 = Len((*_4));                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-+         _0 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageDead(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:13: +1:14
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+2:2: +2:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_len.SimplifyLocals.diff b/src/test/mir-opt/lower_array_len.array_len.SimplifyLocals.diff
deleted file mode 100644
index 09d571d20a36..000000000000
--- a/src/test/mir-opt/lower_array_len.array_len.SimplifyLocals.diff
+++ /dev/null
@@ -1,22 +0,0 @@
-- // MIR for `array_len` before SimplifyLocals
-+ // MIR for `array_len` after SimplifyLocals
-  
-  fn array_len(_1: &[u8; N]) -> usize {
-      debug arr => _1;                     // in scope 0 at $DIR/lower_array_len.rs:+0:34: +0:37
-      let mut _0: usize;                   // return place in scope 0 at $DIR/lower_array_len.rs:+0:52: +0:57
--     let mut _2: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--     let mut _3: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--     let mut _4: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-  
-      bb0: {
--         StorageLive(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:7: +1:8
-          _0 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageDead(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:13: +1:14
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+2:2: +2:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_len_by_value.InstCombine.diff b/src/test/mir-opt/lower_array_len.array_len_by_value.InstCombine.diff
deleted file mode 100644
index 843da758deb1..000000000000
--- a/src/test/mir-opt/lower_array_len.array_len_by_value.InstCombine.diff
+++ /dev/null
@@ -1,26 +0,0 @@
-- // MIR for `array_len_by_value` before InstCombine
-+ // MIR for `array_len_by_value` after InstCombine
-  
-  fn array_len_by_value(_1: [u8; N]) -> usize {
-      debug arr => _1;                     // in scope 0 at $DIR/lower_array_len.rs:+0:43: +0:46
-      let mut _0: usize;                   // return place in scope 0 at $DIR/lower_array_len.rs:+0:60: +0:65
-      let mut _2: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-      let mut _3: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-      let mut _4: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-  
-      bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          _3 = &_1;                        // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          _4 = _3;                         // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          _2 = move _3 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:7: +1:8
--         _0 = Len((*_4));                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-+         _0 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-          StorageDead(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:13: +1:14
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+2:2: +2:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.array_len_by_value.SimplifyLocals.diff b/src/test/mir-opt/lower_array_len.array_len_by_value.SimplifyLocals.diff
deleted file mode 100644
index dc1c00b69c13..000000000000
--- a/src/test/mir-opt/lower_array_len.array_len_by_value.SimplifyLocals.diff
+++ /dev/null
@@ -1,22 +0,0 @@
-- // MIR for `array_len_by_value` before SimplifyLocals
-+ // MIR for `array_len_by_value` after SimplifyLocals
-  
-  fn array_len_by_value(_1: [u8; N]) -> usize {
-      debug arr => _1;                     // in scope 0 at $DIR/lower_array_len.rs:+0:43: +0:46
-      let mut _0: usize;                   // return place in scope 0 at $DIR/lower_array_len.rs:+0:60: +0:65
--     let mut _2: &[u8];                   // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--     let mut _3: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--     let mut _4: &[u8; N];                // in scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
-  
-      bb0: {
--         StorageLive(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:+1:7: +1:8
-          _0 = const N;                    // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:+1:5: +1:14
--         StorageDead(_2);                 // scope 0 at $DIR/lower_array_len.rs:+1:13: +1:14
-          return;                          // scope 0 at $DIR/lower_array_len.rs:+2:2: +2:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/lower_array_len.rs b/src/test/mir-opt/lower_array_len.rs
index fc12ee75fcfc..ea0224b21d72 100644
--- a/src/test/mir-opt/lower_array_len.rs
+++ b/src/test/mir-opt/lower_array_len.rs
@@ -1,8 +1,7 @@
-// compile-flags: -Z mir-opt-level=4
+// unit-test: NormalizeArrayLen
+// compile-flags: -Zmir-enable-passes=+LowerSliceLenCalls
 
 // EMIT_MIR lower_array_len.array_bound.NormalizeArrayLen.diff
-// EMIT_MIR lower_array_len.array_bound.SimplifyLocals.diff
-// EMIT_MIR lower_array_len.array_bound.InstCombine.diff
 pub fn array_bound<const N: usize>(index: usize, slice: &[u8; N]) -> u8 {
     if index < slice.len() {
         slice[index]
@@ -12,8 +11,6 @@ pub fn array_bound<const N: usize>(index: usize, slice: &[u8; N]) -> u8 {
 }
 
 // EMIT_MIR lower_array_len.array_bound_mut.NormalizeArrayLen.diff
-// EMIT_MIR lower_array_len.array_bound_mut.SimplifyLocals.diff
-// EMIT_MIR lower_array_len.array_bound_mut.InstCombine.diff
 pub fn array_bound_mut<const N: usize>(index: usize, slice: &mut [u8; N]) -> u8 {
     if index < slice.len() {
         slice[index]
@@ -25,15 +22,11 @@ pub fn array_bound_mut<const N: usize>(index: usize, slice: &mut [u8; N]) -> u8
 }
 
 // EMIT_MIR lower_array_len.array_len.NormalizeArrayLen.diff
-// EMIT_MIR lower_array_len.array_len.SimplifyLocals.diff
-// EMIT_MIR lower_array_len.array_len.InstCombine.diff
 pub fn array_len<const N: usize>(arr: &[u8; N]) -> usize {
     arr.len()
 }
 
 // EMIT_MIR lower_array_len.array_len_by_value.NormalizeArrayLen.diff
-// EMIT_MIR lower_array_len.array_len_by_value.SimplifyLocals.diff
-// EMIT_MIR lower_array_len.array_len_by_value.InstCombine.diff
 pub fn array_len_by_value<const N: usize>(arr: [u8; N]) -> usize {
     arr.len()
 }
diff --git a/src/test/mir-opt/lower_array_len_e2e.array_bound.PreCodegen.after.mir b/src/test/mir-opt/lower_array_len_e2e.array_bound.PreCodegen.after.mir
new file mode 100644
index 000000000000..2c6c93cb1d83
--- /dev/null
+++ b/src/test/mir-opt/lower_array_len_e2e.array_bound.PreCodegen.after.mir
@@ -0,0 +1,49 @@
+// MIR for `array_bound` after PreCodegen
+
+fn array_bound(_1: usize, _2: &[u8; N]) -> u8 {
+    debug index => _1;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+0:36: +0:41
+    debug slice => _2;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+0:50: +0:55
+    let mut _0: u8;                      // return place in scope 0 at $DIR/lower_array_len_e2e.rs:+0:70: +0:72
+    let mut _3: bool;                    // in scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+    let mut _4: usize;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:13
+    let mut _5: usize;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+1:16: +1:27
+    let _6: usize;                       // in scope 0 at $DIR/lower_array_len_e2e.rs:+2:15: +2:20
+    let mut _7: usize;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+    let mut _8: bool;                    // in scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+
+    bb0: {
+        StorageLive(_3);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+        StorageLive(_4);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:13
+        _4 = _1;                         // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:13
+        StorageLive(_5);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:16: +1:27
+        _5 = const N;                    // scope 0 at $DIR/lower_array_len_e2e.rs:+1:16: +1:27
+        _3 = Lt(move _4, move _5);       // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+        StorageDead(_5);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:26: +1:27
+        StorageDead(_4);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:26: +1:27
+        switchInt(move _3) -> [false: bb3, otherwise: bb1]; // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+    }
+
+    bb1: {
+        StorageLive(_6);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+2:15: +2:20
+        _6 = _1;                         // scope 0 at $DIR/lower_array_len_e2e.rs:+2:15: +2:20
+        _7 = const N;                    // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+        _8 = Lt(_6, _7);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+        assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb2; // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+    }
+
+    bb2: {
+        _0 = (*_2)[_6];                  // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+        StorageDead(_6);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+3:5: +3:6
+        goto -> bb4;                     // scope 0 at $DIR/lower_array_len_e2e.rs:+1:5: +5:6
+    }
+
+    bb3: {
+        _0 = const 42_u8;                // scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:11
+        goto -> bb4;                     // scope 0 at $DIR/lower_array_len_e2e.rs:+1:5: +5:6
+    }
+
+    bb4: {
+        StorageDead(_3);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+5:5: +5:6
+        return;                          // scope 0 at $DIR/lower_array_len_e2e.rs:+6:2: +6:2
+    }
+}
diff --git a/src/test/mir-opt/lower_array_len_e2e.array_bound_mut.PreCodegen.after.mir b/src/test/mir-opt/lower_array_len_e2e.array_bound_mut.PreCodegen.after.mir
new file mode 100644
index 000000000000..aee3a8242cdd
--- /dev/null
+++ b/src/test/mir-opt/lower_array_len_e2e.array_bound_mut.PreCodegen.after.mir
@@ -0,0 +1,62 @@
+// MIR for `array_bound_mut` after PreCodegen
+
+fn array_bound_mut(_1: usize, _2: &mut [u8; N]) -> u8 {
+    debug index => _1;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+0:40: +0:45
+    debug slice => _2;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+0:54: +0:59
+    let mut _0: u8;                      // return place in scope 0 at $DIR/lower_array_len_e2e.rs:+0:78: +0:80
+    let mut _3: bool;                    // in scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+    let mut _4: usize;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:13
+    let mut _5: usize;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+1:16: +1:27
+    let _6: usize;                       // in scope 0 at $DIR/lower_array_len_e2e.rs:+2:15: +2:20
+    let mut _7: usize;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+    let mut _8: bool;                    // in scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+    let _9: usize;                       // in scope 0 at $DIR/lower_array_len_e2e.rs:+4:15: +4:16
+    let mut _10: usize;                  // in scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:17
+    let mut _11: bool;                   // in scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:17
+
+    bb0: {
+        StorageLive(_3);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+        StorageLive(_4);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:13
+        _4 = _1;                         // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:13
+        StorageLive(_5);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:16: +1:27
+        _5 = const N;                    // scope 0 at $DIR/lower_array_len_e2e.rs:+1:16: +1:27
+        _3 = Lt(move _4, move _5);       // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+        StorageDead(_5);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:26: +1:27
+        StorageDead(_4);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+1:26: +1:27
+        switchInt(move _3) -> [false: bb3, otherwise: bb1]; // scope 0 at $DIR/lower_array_len_e2e.rs:+1:8: +1:27
+    }
+
+    bb1: {
+        StorageLive(_6);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+2:15: +2:20
+        _6 = _1;                         // scope 0 at $DIR/lower_array_len_e2e.rs:+2:15: +2:20
+        _7 = const N;                    // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+        _8 = Lt(_6, _7);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+        assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb2; // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+    }
+
+    bb2: {
+        _0 = (*_2)[_6];                  // scope 0 at $DIR/lower_array_len_e2e.rs:+2:9: +2:21
+        StorageDead(_6);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+3:5: +3:6
+        goto -> bb5;                     // scope 0 at $DIR/lower_array_len_e2e.rs:+1:5: +7:6
+    }
+
+    bb3: {
+        StorageLive(_9);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+4:15: +4:16
+        _9 = const 0_usize;              // scope 0 at $DIR/lower_array_len_e2e.rs:+4:15: +4:16
+        _10 = const N;                   // scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:17
+        _11 = Lt(const 0_usize, _10);    // scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:17
+        assert(move _11, "index out of bounds: the length is {} but the index is {}", move _10, const 0_usize) -> bb4; // scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:17
+    }
+
+    bb4: {
+        (*_2)[_9] = const 42_u8;         // scope 0 at $DIR/lower_array_len_e2e.rs:+4:9: +4:22
+        StorageDead(_9);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+4:22: +4:23
+        _0 = const 42_u8;                // scope 0 at $DIR/lower_array_len_e2e.rs:+6:9: +6:11
+        goto -> bb5;                     // scope 0 at $DIR/lower_array_len_e2e.rs:+1:5: +7:6
+    }
+
+    bb5: {
+        StorageDead(_3);                 // scope 0 at $DIR/lower_array_len_e2e.rs:+7:5: +7:6
+        return;                          // scope 0 at $DIR/lower_array_len_e2e.rs:+8:2: +8:2
+    }
+}
diff --git a/src/test/mir-opt/lower_array_len_e2e.array_len.PreCodegen.after.mir b/src/test/mir-opt/lower_array_len_e2e.array_len.PreCodegen.after.mir
new file mode 100644
index 000000000000..4b19f6795588
--- /dev/null
+++ b/src/test/mir-opt/lower_array_len_e2e.array_len.PreCodegen.after.mir
@@ -0,0 +1,11 @@
+// MIR for `array_len` after PreCodegen
+
+fn array_len(_1: &[u8; N]) -> usize {
+    debug arr => _1;                     // in scope 0 at $DIR/lower_array_len_e2e.rs:+0:34: +0:37
+    let mut _0: usize;                   // return place in scope 0 at $DIR/lower_array_len_e2e.rs:+0:52: +0:57
+
+    bb0: {
+        _0 = const N;                    // scope 0 at $DIR/lower_array_len_e2e.rs:+1:5: +1:14
+        return;                          // scope 0 at $DIR/lower_array_len_e2e.rs:+2:2: +2:2
+    }
+}
diff --git a/src/test/mir-opt/lower_array_len_e2e.array_len_by_value.PreCodegen.after.mir b/src/test/mir-opt/lower_array_len_e2e.array_len_by_value.PreCodegen.after.mir
new file mode 100644
index 000000000000..4dc0ba9a268e
--- /dev/null
+++ b/src/test/mir-opt/lower_array_len_e2e.array_len_by_value.PreCodegen.after.mir
@@ -0,0 +1,11 @@
+// MIR for `array_len_by_value` after PreCodegen
+
+fn array_len_by_value(_1: [u8; N]) -> usize {
+    debug arr => _1;                     // in scope 0 at $DIR/lower_array_len_e2e.rs:+0:43: +0:46
+    let mut _0: usize;                   // return place in scope 0 at $DIR/lower_array_len_e2e.rs:+0:60: +0:65
+
+    bb0: {
+        _0 = const N;                    // scope 0 at $DIR/lower_array_len_e2e.rs:+1:5: +1:14
+        return;                          // scope 0 at $DIR/lower_array_len_e2e.rs:+2:2: +2:2
+    }
+}
diff --git a/src/test/mir-opt/lower_array_len_e2e.rs b/src/test/mir-opt/lower_array_len_e2e.rs
new file mode 100644
index 000000000000..49b35d509f02
--- /dev/null
+++ b/src/test/mir-opt/lower_array_len_e2e.rs
@@ -0,0 +1,39 @@
+// compile-flags: -Z mir-opt-level=4
+
+// EMIT_MIR lower_array_len_e2e.array_bound.PreCodegen.after.mir
+pub fn array_bound<const N: usize>(index: usize, slice: &[u8; N]) -> u8 {
+    if index < slice.len() {
+        slice[index]
+    } else {
+        42
+    }
+}
+
+// EMIT_MIR lower_array_len_e2e.array_bound_mut.PreCodegen.after.mir
+pub fn array_bound_mut<const N: usize>(index: usize, slice: &mut [u8; N]) -> u8 {
+    if index < slice.len() {
+        slice[index]
+    } else {
+        slice[0] = 42;
+
+        42
+    }
+}
+
+// EMIT_MIR lower_array_len_e2e.array_len.PreCodegen.after.mir
+pub fn array_len<const N: usize>(arr: &[u8; N]) -> usize {
+    arr.len()
+}
+
+// EMIT_MIR lower_array_len_e2e.array_len_by_value.PreCodegen.after.mir
+pub fn array_len_by_value<const N: usize>(arr: [u8; N]) -> usize {
+    arr.len()
+}
+
+fn main() {
+    let _ = array_bound(3, &[0, 1, 2, 3]);
+    let mut tmp = [0, 1, 2, 3, 4];
+    let _ = array_bound_mut(3, &mut [0, 1, 2, 3]);
+    let _ = array_len(&[0]);
+    let _ = array_len_by_value([0, 2]);
+}
diff --git a/src/test/mir-opt/lower_intrinsics.align_of.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.align_of.LowerIntrinsics.diff
index 5c635e2220ed..3389db733b99 100644
--- a/src/test/mir-opt/lower_intrinsics.align_of.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.align_of.LowerIntrinsics.diff
@@ -7,7 +7,7 @@
       bb0: {
 -         _0 = std::intrinsics::min_align_of::<T>() -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:42
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:19:5: 19:40
+-                                          // + span: $DIR/lower_intrinsics.rs:21:5: 21:40
 -                                          // + literal: Const { ty: extern "rust-intrinsic" fn() -> usize {std::intrinsics::min_align_of::<T>}, val: Value(<ZST>) }
 +         _0 = AlignOf(T);                 // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:42
 +         goto -> bb1;                     // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:42
diff --git a/src/test/mir-opt/lower_intrinsics.assume.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.assume.LowerIntrinsics.diff
new file mode 100644
index 000000000000..d9898d8e0f01
--- /dev/null
+++ b/src/test/mir-opt/lower_intrinsics.assume.LowerIntrinsics.diff
@@ -0,0 +1,26 @@
+- // MIR for `assume` before LowerIntrinsics
++ // MIR for `assume` after LowerIntrinsics
+  
+  fn assume() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/lower_intrinsics.rs:+0:17: +0:17
+      let _1: ();                          // in scope 0 at $DIR/lower_intrinsics.rs:+2:9: +2:38
+      scope 1 {
+      }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 1 at $DIR/lower_intrinsics.rs:+2:9: +2:38
+-         _1 = std::intrinsics::assume(const true) -> bb1; // scope 1 at $DIR/lower_intrinsics.rs:+2:9: +2:38
+-                                          // mir::Constant
+-                                          // + span: $DIR/lower_intrinsics.rs:72:9: 72:32
+-                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(bool) {std::intrinsics::assume}, val: Value(<ZST>) }
++         assume(const true);              // scope 1 at $DIR/lower_intrinsics.rs:+2:9: +2:38
++         goto -> bb1;                     // scope 1 at $DIR/lower_intrinsics.rs:+2:9: +2:38
+      }
+  
+      bb1: {
+          StorageDead(_1);                 // scope 1 at $DIR/lower_intrinsics.rs:+2:38: +2:39
+          _0 = const ();                   // scope 1 at $DIR/lower_intrinsics.rs:+1:5: +3:6
+          return;                          // scope 0 at $DIR/lower_intrinsics.rs:+4:2: +4:2
+      }
+  }
+  
diff --git a/src/test/mir-opt/lower_intrinsics.discriminant.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.discriminant.LowerIntrinsics.diff
index 8a80de32f3ae..d962ef8cb12d 100644
--- a/src/test/mir-opt/lower_intrinsics.discriminant.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.discriminant.LowerIntrinsics.diff
@@ -31,8 +31,8 @@
           _3 = &(*_4);                     // scope 0 at $DIR/lower_intrinsics.rs:+1:42: +1:44
 -         _2 = discriminant_value::<T>(move _3) -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:45
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:74:5: 74:41
--                                          // + literal: Const { ty: for<'r> extern "rust-intrinsic" fn(&'r T) -> <T as DiscriminantKind>::Discriminant {discriminant_value::<T>}, val: Value(<ZST>) }
+-                                          // + span: $DIR/lower_intrinsics.rs:49:5: 49:41
+-                                          // + literal: Const { ty: for<'a> extern "rust-intrinsic" fn(&'a T) -> <T as DiscriminantKind>::Discriminant {discriminant_value::<T>}, val: Value(<ZST>) }
 +         _2 = discriminant((*_3));        // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:45
 +         goto -> bb1;                     // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:45
       }
@@ -44,16 +44,16 @@
           StorageLive(_5);                 // scope 0 at $DIR/lower_intrinsics.rs:+2:5: +2:45
           StorageLive(_6);                 // scope 0 at $DIR/lower_intrinsics.rs:+2:42: +2:44
           StorageLive(_7);                 // scope 0 at $DIR/lower_intrinsics.rs:+2:42: +2:44
-          _19 = const discriminant::<T>::promoted[2]; // scope 0 at $DIR/lower_intrinsics.rs:+2:42: +2:44
+          _19 = const _;                   // scope 0 at $DIR/lower_intrinsics.rs:+2:42: +2:44
                                            // mir::Constant
-                                           // + span: $DIR/lower_intrinsics.rs:75:42: 75:44
+                                           // + span: $DIR/lower_intrinsics.rs:50:42: 50:44
                                            // + literal: Const { ty: &i32, val: Unevaluated(discriminant, [T], Some(promoted[2])) }
           _7 = &(*_19);                    // scope 0 at $DIR/lower_intrinsics.rs:+2:42: +2:44
           _6 = &(*_7);                     // scope 0 at $DIR/lower_intrinsics.rs:+2:42: +2:44
 -         _5 = discriminant_value::<i32>(move _6) -> bb2; // scope 0 at $DIR/lower_intrinsics.rs:+2:5: +2:45
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:75:5: 75:41
--                                          // + literal: Const { ty: for<'r> extern "rust-intrinsic" fn(&'r i32) -> <i32 as DiscriminantKind>::Discriminant {discriminant_value::<i32>}, val: Value(<ZST>) }
+-                                          // + span: $DIR/lower_intrinsics.rs:50:5: 50:41
+-                                          // + literal: Const { ty: for<'a> extern "rust-intrinsic" fn(&'a i32) -> <i32 as DiscriminantKind>::Discriminant {discriminant_value::<i32>}, val: Value(<ZST>) }
 +         _5 = discriminant((*_6));        // scope 0 at $DIR/lower_intrinsics.rs:+2:5: +2:45
 +         goto -> bb2;                     // scope 0 at $DIR/lower_intrinsics.rs:+2:5: +2:45
       }
@@ -65,16 +65,16 @@
           StorageLive(_9);                 // scope 0 at $DIR/lower_intrinsics.rs:+3:5: +3:46
           StorageLive(_10);                // scope 0 at $DIR/lower_intrinsics.rs:+3:42: +3:45
           StorageLive(_11);                // scope 0 at $DIR/lower_intrinsics.rs:+3:42: +3:45
-          _18 = const discriminant::<T>::promoted[1]; // scope 0 at $DIR/lower_intrinsics.rs:+3:42: +3:45
+          _18 = const _;                   // scope 0 at $DIR/lower_intrinsics.rs:+3:42: +3:45
                                            // mir::Constant
-                                           // + span: $DIR/lower_intrinsics.rs:76:42: 76:45
+                                           // + span: $DIR/lower_intrinsics.rs:51:42: 51:45
                                            // + literal: Const { ty: &(), val: Unevaluated(discriminant, [T], Some(promoted[1])) }
           _11 = &(*_18);                   // scope 0 at $DIR/lower_intrinsics.rs:+3:42: +3:45
           _10 = &(*_11);                   // scope 0 at $DIR/lower_intrinsics.rs:+3:42: +3:45
 -         _9 = discriminant_value::<()>(move _10) -> bb3; // scope 0 at $DIR/lower_intrinsics.rs:+3:5: +3:46
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:76:5: 76:41
--                                          // + literal: Const { ty: for<'r> extern "rust-intrinsic" fn(&'r ()) -> <() as DiscriminantKind>::Discriminant {discriminant_value::<()>}, val: Value(<ZST>) }
+-                                          // + span: $DIR/lower_intrinsics.rs:51:5: 51:41
+-                                          // + literal: Const { ty: for<'a> extern "rust-intrinsic" fn(&'a ()) -> <() as DiscriminantKind>::Discriminant {discriminant_value::<()>}, val: Value(<ZST>) }
 +         _9 = discriminant((*_10));       // scope 0 at $DIR/lower_intrinsics.rs:+3:5: +3:46
 +         goto -> bb3;                     // scope 0 at $DIR/lower_intrinsics.rs:+3:5: +3:46
       }
@@ -86,16 +86,16 @@
           StorageLive(_13);                // scope 0 at $DIR/lower_intrinsics.rs:+4:5: +4:48
           StorageLive(_14);                // scope 0 at $DIR/lower_intrinsics.rs:+4:42: +4:47
           StorageLive(_15);                // scope 0 at $DIR/lower_intrinsics.rs:+4:42: +4:47
-          _17 = const discriminant::<T>::promoted[0]; // scope 0 at $DIR/lower_intrinsics.rs:+4:42: +4:47
+          _17 = const _;                   // scope 0 at $DIR/lower_intrinsics.rs:+4:42: +4:47
                                            // mir::Constant
-                                           // + span: $DIR/lower_intrinsics.rs:77:42: 77:47
+                                           // + span: $DIR/lower_intrinsics.rs:52:42: 52:47
                                            // + literal: Const { ty: &E, val: Unevaluated(discriminant, [T], Some(promoted[0])) }
           _15 = &(*_17);                   // scope 0 at $DIR/lower_intrinsics.rs:+4:42: +4:47
           _14 = &(*_15);                   // scope 0 at $DIR/lower_intrinsics.rs:+4:42: +4:47
 -         _13 = discriminant_value::<E>(move _14) -> bb4; // scope 0 at $DIR/lower_intrinsics.rs:+4:5: +4:48
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:77:5: 77:41
--                                          // + literal: Const { ty: for<'r> extern "rust-intrinsic" fn(&'r E) -> <E as DiscriminantKind>::Discriminant {discriminant_value::<E>}, val: Value(<ZST>) }
+-                                          // + span: $DIR/lower_intrinsics.rs:52:5: 52:41
+-                                          // + literal: Const { ty: for<'a> extern "rust-intrinsic" fn(&'a E) -> <E as DiscriminantKind>::Discriminant {discriminant_value::<E>}, val: Value(<ZST>) }
 +         _13 = discriminant((*_14));      // scope 0 at $DIR/lower_intrinsics.rs:+4:5: +4:48
 +         goto -> bb4;                     // scope 0 at $DIR/lower_intrinsics.rs:+4:5: +4:48
       }
@@ -105,11 +105,15 @@
           StorageDead(_15);                // scope 0 at $DIR/lower_intrinsics.rs:+4:48: +4:49
           StorageDead(_13);                // scope 0 at $DIR/lower_intrinsics.rs:+4:48: +4:49
           _0 = const ();                   // scope 0 at $DIR/lower_intrinsics.rs:+0:30: +5:2
-          drop(_1) -> bb5;                 // scope 0 at $DIR/lower_intrinsics.rs:+5:1: +5:2
+          drop(_1) -> [return: bb5, unwind: bb6]; // scope 0 at $DIR/lower_intrinsics.rs:+5:1: +5:2
       }
   
       bb5: {
           return;                          // scope 0 at $DIR/lower_intrinsics.rs:+5:2: +5:2
       }
+  
+      bb6 (cleanup): {
+          resume;                          // scope 0 at $DIR/lower_intrinsics.rs:+0:1: +5:2
+      }
   }
   
diff --git a/src/test/mir-opt/lower_intrinsics.f_copy_nonoverlapping.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.f_copy_nonoverlapping.LowerIntrinsics.diff
new file mode 100644
index 000000000000..4fb6752b6196
--- /dev/null
+++ b/src/test/mir-opt/lower_intrinsics.f_copy_nonoverlapping.LowerIntrinsics.diff
@@ -0,0 +1,72 @@
+- // MIR for `f_copy_nonoverlapping` before LowerIntrinsics
++ // MIR for `f_copy_nonoverlapping` after LowerIntrinsics
+  
+  fn f_copy_nonoverlapping() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/lower_intrinsics.rs:+0:32: +0:32
+      let _1: ();                          // in scope 0 at $DIR/lower_intrinsics.rs:+1:9: +1:12
+      let _3: ();                          // in scope 0 at $DIR/lower_intrinsics.rs:+4:9: +4:95
+      let mut _4: *const i32;              // in scope 0 at $DIR/lower_intrinsics.rs:+4:29: +4:59
+      let mut _5: *const ();               // in scope 0 at $DIR/lower_intrinsics.rs:+4:29: +4:45
+      let mut _6: *const ();               // in scope 0 at $DIR/lower_intrinsics.rs:+4:29: +4:45
+      let _7: &();                         // in scope 0 at $DIR/lower_intrinsics.rs:+4:29: +4:33
+      let mut _8: *mut i32;                // in scope 0 at $DIR/lower_intrinsics.rs:+4:61: +4:91
+      let mut _9: *mut ();                 // in scope 0 at $DIR/lower_intrinsics.rs:+4:61: +4:79
+      let mut _10: *mut ();                // in scope 0 at $DIR/lower_intrinsics.rs:+4:61: +4:79
+      let mut _11: &mut ();                // in scope 0 at $DIR/lower_intrinsics.rs:+4:61: +4:69
+      scope 1 {
+          debug src => _1;                 // in scope 1 at $DIR/lower_intrinsics.rs:+1:9: +1:12
+          let mut _2: ();                  // in scope 1 at $DIR/lower_intrinsics.rs:+2:9: +2:16
+          scope 2 {
+              debug dst => _2;             // in scope 2 at $DIR/lower_intrinsics.rs:+2:9: +2:16
+              scope 3 {
+              }
+          }
+      }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+1:9: +1:12
+          Deinit(_1);                      // scope 0 at $DIR/lower_intrinsics.rs:+1:15: +1:17
+          StorageLive(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:+2:9: +2:16
+          Deinit(_2);                      // scope 1 at $DIR/lower_intrinsics.rs:+2:19: +2:21
+          StorageLive(_3);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:9: +4:95
+          StorageLive(_4);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:59
+          StorageLive(_5);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:45
+          StorageLive(_6);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:45
+          StorageLive(_7);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:33
+          _7 = &_1;                        // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:33
+          _6 = &raw const (*_7);           // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:33
+          _5 = _6;                         // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:45
+          _4 = move _5 as *const i32 (Misc); // scope 3 at $DIR/lower_intrinsics.rs:+4:29: +4:59
+          StorageDead(_5);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:58: +4:59
+          StorageLive(_8);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:91
+          StorageLive(_9);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:79
+          StorageLive(_10);                // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:79
+          StorageLive(_11);                // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:69
+          _11 = &mut _2;                   // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:69
+          _10 = &raw mut (*_11);           // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:69
+          _9 = _10;                        // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:79
+          _8 = move _9 as *mut i32 (Misc); // scope 3 at $DIR/lower_intrinsics.rs:+4:61: +4:91
+          StorageDead(_9);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:90: +4:91
+-         _3 = copy_nonoverlapping::<i32>(move _4, move _8, const 0_usize) -> bb1; // scope 3 at $DIR/lower_intrinsics.rs:+4:9: +4:95
+-                                          // mir::Constant
+-                                          // + span: $DIR/lower_intrinsics.rs:65:9: 65:28
+-                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(*const i32, *mut i32, usize) {copy_nonoverlapping::<i32>}, val: Value(<ZST>) }
++         copy_nonoverlapping(dst = move _8, src = move _4, count = const 0_usize); // scope 3 at $DIR/lower_intrinsics.rs:+4:9: +4:95
++         goto -> bb1;                     // scope 3 at $DIR/lower_intrinsics.rs:+4:9: +4:95
+      }
+  
+      bb1: {
+          StorageDead(_8);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:94: +4:95
+          StorageDead(_4);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:94: +4:95
+          StorageDead(_11);                // scope 3 at $DIR/lower_intrinsics.rs:+4:95: +4:96
+          StorageDead(_10);                // scope 3 at $DIR/lower_intrinsics.rs:+4:95: +4:96
+          StorageDead(_7);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:95: +4:96
+          StorageDead(_6);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:95: +4:96
+          StorageDead(_3);                 // scope 3 at $DIR/lower_intrinsics.rs:+4:95: +4:96
+          _0 = const ();                   // scope 3 at $DIR/lower_intrinsics.rs:+3:5: +5:6
+          StorageDead(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:+6:1: +6:2
+          StorageDead(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+6:1: +6:2
+          return;                          // scope 0 at $DIR/lower_intrinsics.rs:+6:2: +6:2
+      }
+  }
+  
diff --git a/src/test/mir-opt/lower_intrinsics.forget.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.forget.LowerIntrinsics.diff
index e6a2f6512f55..4cbbc02c9433 100644
--- a/src/test/mir-opt/lower_intrinsics.forget.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.forget.LowerIntrinsics.diff
@@ -11,7 +11,7 @@
           _2 = move _1;                    // scope 0 at $DIR/lower_intrinsics.rs:+1:30: +1:31
 -         _0 = std::intrinsics::forget::<T>(move _2) -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:32
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:24:5: 24:29
+-                                          // + span: $DIR/lower_intrinsics.rs:26:5: 26:29
 -                                          // + literal: Const { ty: extern "rust-intrinsic" fn(T) {std::intrinsics::forget::<T>}, val: Value(<ZST>) }
 +         _0 = const ();                   // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:32
 +         goto -> bb1;                     // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:32
diff --git a/src/test/mir-opt/lower_intrinsics.non_const.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.non_const.LowerIntrinsics.diff
index 1ab2f2a0a046..d8cd5f59a353 100644
--- a/src/test/mir-opt/lower_intrinsics.non_const.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.non_const.LowerIntrinsics.diff
@@ -13,7 +13,7 @@
           StorageLive(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+2:9: +2:18
           _1 = std::intrinsics::size_of::<T>; // scope 0 at $DIR/lower_intrinsics.rs:+2:21: +2:51
                                            // mir::Constant
-                                           // + span: $DIR/lower_intrinsics.rs:62:21: 62:51
+                                           // + span: $DIR/lower_intrinsics.rs:37:21: 37:51
                                            // + literal: Const { ty: extern "rust-intrinsic" fn() -> usize {std::intrinsics::size_of::<T>}, val: Value(<ZST>) }
           StorageLive(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:+3:5: +3:14
           _2 = _1;                         // scope 1 at $DIR/lower_intrinsics.rs:+3:5: +3:14
diff --git a/src/test/mir-opt/lower_intrinsics.rs b/src/test/mir-opt/lower_intrinsics.rs
index eab51b65f1a1..66dae0e46b9d 100644
--- a/src/test/mir-opt/lower_intrinsics.rs
+++ b/src/test/mir-opt/lower_intrinsics.rs
@@ -1,5 +1,7 @@
-// compile-flags: -Cpanic=abort
-#![feature(core_intrinsics)]
+// unit-test: LowerIntrinsics
+// ignore-wasm32 compiled with panic=abort by default
+
+#![feature(core_intrinsics, intrinsics)]
 #![crate_type = "lib"]
 
 // EMIT_MIR lower_intrinsics.wrapping.LowerIntrinsics.diff
@@ -29,33 +31,6 @@ pub fn unreachable() -> ! {
     unsafe { core::intrinsics::unreachable() };
 }
 
-// EMIT_MIR lower_intrinsics.f_unit.PreCodegen.before.mir
-pub fn f_unit() {
-    f_dispatch(());
-}
-
-
-// EMIT_MIR lower_intrinsics.f_u64.PreCodegen.before.mir
-pub fn f_u64() {
-    f_dispatch(0u64);
-}
-
-#[inline(always)]
-pub fn f_dispatch<T>(t: T) {
-    if std::mem::size_of::<T>() == 0 {
-        f_zst(t);
-    } else {
-        f_non_zst(t);
-    }
-}
-
-#[inline(never)]
-pub fn f_zst<T>(_t: T) {
-}
-
-#[inline(never)]
-pub fn f_non_zst<T>(_t: T) {}
-
 // EMIT_MIR lower_intrinsics.non_const.LowerIntrinsics.diff
 pub fn non_const<T>() -> usize {
     // Check that lowering works with non-const operand as a func.
@@ -76,3 +51,24 @@ pub fn discriminant<T>(t: T) {
     core::intrinsics::discriminant_value(&());
     core::intrinsics::discriminant_value(&E::B);
 }
+
+extern "rust-intrinsic" {
+    // Cannot use `std::intrinsics::copy_nonoverlapping` as that is a wrapper function
+    fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+}
+
+// EMIT_MIR lower_intrinsics.f_copy_nonoverlapping.LowerIntrinsics.diff
+pub fn f_copy_nonoverlapping() {
+    let src = ();
+    let mut dst = ();
+    unsafe {
+        copy_nonoverlapping(&src as *const _ as *const i32, &mut dst as *mut _ as *mut i32, 0);
+    }
+}
+
+// EMIT_MIR lower_intrinsics.assume.LowerIntrinsics.diff
+pub fn assume() {
+    unsafe {
+        std::intrinsics::assume(true);
+    }
+}
diff --git a/src/test/mir-opt/lower_intrinsics.size_of.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.size_of.LowerIntrinsics.diff
index 11b27976b551..cf0ab73a5d4b 100644
--- a/src/test/mir-opt/lower_intrinsics.size_of.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.size_of.LowerIntrinsics.diff
@@ -7,7 +7,7 @@
       bb0: {
 -         _0 = std::intrinsics::size_of::<T>() -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:37
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:14:5: 14:35
+-                                          // + span: $DIR/lower_intrinsics.rs:16:5: 16:35
 -                                          // + literal: Const { ty: extern "rust-intrinsic" fn() -> usize {std::intrinsics::size_of::<T>}, val: Value(<ZST>) }
 +         _0 = SizeOf(T);                  // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:37
 +         goto -> bb1;                     // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:37
diff --git a/src/test/mir-opt/lower_intrinsics.unreachable.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.unreachable.LowerIntrinsics.diff
index ac077e85b04f..6f17d44516de 100644
--- a/src/test/mir-opt/lower_intrinsics.unreachable.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.unreachable.LowerIntrinsics.diff
@@ -14,7 +14,7 @@
           StorageLive(_3);                 // scope 1 at $DIR/lower_intrinsics.rs:+1:14: +1:45
 -         _3 = std::intrinsics::unreachable(); // scope 1 at $DIR/lower_intrinsics.rs:+1:14: +1:45
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:29:14: 29:43
+-                                          // + span: $DIR/lower_intrinsics.rs:31:14: 31:43
 -                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn() -> ! {std::intrinsics::unreachable}, val: Value(<ZST>) }
 +         unreachable;                     // scope 1 at $DIR/lower_intrinsics.rs:+1:14: +1:45
       }
diff --git a/src/test/mir-opt/lower_intrinsics.wrapping.LowerIntrinsics.diff b/src/test/mir-opt/lower_intrinsics.wrapping.LowerIntrinsics.diff
index e0a5416b22b5..22ef75fd8046 100644
--- a/src/test/mir-opt/lower_intrinsics.wrapping.LowerIntrinsics.diff
+++ b/src/test/mir-opt/lower_intrinsics.wrapping.LowerIntrinsics.diff
@@ -32,7 +32,7 @@
           _5 = _2;                         // scope 0 at $DIR/lower_intrinsics.rs:+1:48: +1:49
 -         _3 = wrapping_add::<i32>(move _4, move _5) -> bb1; // scope 0 at $DIR/lower_intrinsics.rs:+1:14: +1:50
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:7:14: 7:44
+-                                          // + span: $DIR/lower_intrinsics.rs:9:14: 9:44
 -                                          // + literal: Const { ty: extern "rust-intrinsic" fn(i32, i32) -> i32 {wrapping_add::<i32>}, val: Value(<ZST>) }
 +         _3 = Add(move _4, move _5);      // scope 0 at $DIR/lower_intrinsics.rs:+1:14: +1:50
 +         goto -> bb1;                     // scope 0 at $DIR/lower_intrinsics.rs:+1:14: +1:50
@@ -48,7 +48,7 @@
           _8 = _2;                         // scope 1 at $DIR/lower_intrinsics.rs:+2:48: +2:49
 -         _6 = wrapping_sub::<i32>(move _7, move _8) -> bb2; // scope 1 at $DIR/lower_intrinsics.rs:+2:14: +2:50
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:8:14: 8:44
+-                                          // + span: $DIR/lower_intrinsics.rs:10:14: 10:44
 -                                          // + literal: Const { ty: extern "rust-intrinsic" fn(i32, i32) -> i32 {wrapping_sub::<i32>}, val: Value(<ZST>) }
 +         _6 = Sub(move _7, move _8);      // scope 1 at $DIR/lower_intrinsics.rs:+2:14: +2:50
 +         goto -> bb2;                     // scope 1 at $DIR/lower_intrinsics.rs:+2:14: +2:50
@@ -64,7 +64,7 @@
           _11 = _2;                        // scope 2 at $DIR/lower_intrinsics.rs:+3:48: +3:49
 -         _9 = wrapping_mul::<i32>(move _10, move _11) -> bb3; // scope 2 at $DIR/lower_intrinsics.rs:+3:14: +3:50
 -                                          // mir::Constant
--                                          // + span: $DIR/lower_intrinsics.rs:9:14: 9:44
+-                                          // + span: $DIR/lower_intrinsics.rs:11:14: 11:44
 -                                          // + literal: Const { ty: extern "rust-intrinsic" fn(i32, i32) -> i32 {wrapping_mul::<i32>}, val: Value(<ZST>) }
 +         _9 = Mul(move _10, move _11);    // scope 2 at $DIR/lower_intrinsics.rs:+3:14: +3:50
 +         goto -> bb3;                     // scope 2 at $DIR/lower_intrinsics.rs:+3:14: +3:50
diff --git a/src/test/mir-opt/lower_intrinsics.f_u64.PreCodegen.before.mir b/src/test/mir-opt/lower_intrinsics_e2e.f_u64.PreCodegen.after.mir
similarity index 68%
rename from src/test/mir-opt/lower_intrinsics.f_u64.PreCodegen.before.mir
rename to src/test/mir-opt/lower_intrinsics_e2e.f_u64.PreCodegen.after.mir
index 2a9a099a38d9..8e185323e1a8 100644
--- a/src/test/mir-opt/lower_intrinsics.f_u64.PreCodegen.before.mir
+++ b/src/test/mir-opt/lower_intrinsics_e2e.f_u64.PreCodegen.after.mir
@@ -1,32 +1,32 @@
-// MIR for `f_u64` before PreCodegen
+// MIR for `f_u64` after PreCodegen
 
 fn f_u64() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/lower_intrinsics.rs:+0:16: +0:16
-    let mut _1: u64;                     // in scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:21
-    scope 1 (inlined f_dispatch::<u64>) { // at $DIR/lower_intrinsics.rs:40:5: 40:21
-        debug t => _1;                   // in scope 1 at $DIR/lower_intrinsics.rs:44:22: 44:23
-        let _2: ();                      // in scope 1 at $DIR/lower_intrinsics.rs:48:9: 48:21
-        let mut _3: u64;                 // in scope 1 at $DIR/lower_intrinsics.rs:48:19: 48:20
-        scope 2 (inlined std::mem::size_of::<u64>) { // at $DIR/lower_intrinsics.rs:45:8: 45:32
+    let mut _0: ();                      // return place in scope 0 at $DIR/lower_intrinsics_e2e.rs:+0:16: +0:16
+    let mut _1: u64;                     // in scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:5: +1:21
+    scope 1 (inlined f_dispatch::<u64>) { // at $DIR/lower_intrinsics_e2e.rs:15:5: 15:21
+        debug t => _1;                   // in scope 1 at $DIR/lower_intrinsics_e2e.rs:19:22: 19:23
+        let _2: ();                      // in scope 1 at $DIR/lower_intrinsics_e2e.rs:23:9: 23:21
+        let mut _3: u64;                 // in scope 1 at $DIR/lower_intrinsics_e2e.rs:23:19: 23:20
+        scope 2 (inlined std::mem::size_of::<u64>) { // at $DIR/lower_intrinsics_e2e.rs:20:8: 20:32
         }
     }
 
     bb0: {
-        StorageLive(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:21
-        _1 = const 0_u64;                // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:21
-        StorageLive(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:48:9: 48:21
-        StorageLive(_3);                 // scope 1 at $DIR/lower_intrinsics.rs:48:19: 48:20
-        _3 = move _1;                    // scope 1 at $DIR/lower_intrinsics.rs:48:19: 48:20
-        _2 = f_non_zst::<u64>(move _3) -> bb1; // scope 1 at $DIR/lower_intrinsics.rs:48:9: 48:21
+        StorageLive(_1);                 // scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:5: +1:21
+        _1 = const 0_u64;                // scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:5: +1:21
+        StorageLive(_2);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:23:9: 23:21
+        StorageLive(_3);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:23:19: 23:20
+        _3 = move _1;                    // scope 1 at $DIR/lower_intrinsics_e2e.rs:23:19: 23:20
+        _2 = f_non_zst::<u64>(move _3) -> bb1; // scope 1 at $DIR/lower_intrinsics_e2e.rs:23:9: 23:21
                                          // mir::Constant
-                                         // + span: $DIR/lower_intrinsics.rs:48:9: 48:18
+                                         // + span: $DIR/lower_intrinsics_e2e.rs:23:9: 23:18
                                          // + literal: Const { ty: fn(u64) {f_non_zst::<u64>}, val: Value(<ZST>) }
     }
 
     bb1: {
-        StorageDead(_3);                 // scope 1 at $DIR/lower_intrinsics.rs:48:20: 48:21
-        StorageDead(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:48:21: 48:22
-        StorageDead(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+1:5: +1:21
-        return;                          // scope 0 at $DIR/lower_intrinsics.rs:+2:2: +2:2
+        StorageDead(_3);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:23:20: 23:21
+        StorageDead(_2);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:23:21: 23:22
+        StorageDead(_1);                 // scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:5: +1:21
+        return;                          // scope 0 at $DIR/lower_intrinsics_e2e.rs:+2:2: +2:2
     }
 }
diff --git a/src/test/mir-opt/lower_intrinsics.f_unit.PreCodegen.before.mir b/src/test/mir-opt/lower_intrinsics_e2e.f_unit.PreCodegen.after.mir
similarity index 68%
rename from src/test/mir-opt/lower_intrinsics.f_unit.PreCodegen.before.mir
rename to src/test/mir-opt/lower_intrinsics_e2e.f_unit.PreCodegen.after.mir
index 5783822f6b54..a5b396ca0bc7 100644
--- a/src/test/mir-opt/lower_intrinsics.f_unit.PreCodegen.before.mir
+++ b/src/test/mir-opt/lower_intrinsics_e2e.f_unit.PreCodegen.after.mir
@@ -1,30 +1,30 @@
-// MIR for `f_unit` before PreCodegen
+// MIR for `f_unit` after PreCodegen
 
 fn f_unit() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/lower_intrinsics.rs:+0:17: +0:17
-    let mut _1: ();                      // in scope 0 at $DIR/lower_intrinsics.rs:+1:16: +1:18
-    scope 1 (inlined f_dispatch::<()>) { // at $DIR/lower_intrinsics.rs:34:5: 34:19
-        debug t => _1;                   // in scope 1 at $DIR/lower_intrinsics.rs:44:22: 44:23
-        let _2: ();                      // in scope 1 at $DIR/lower_intrinsics.rs:46:9: 46:17
-        let mut _3: ();                  // in scope 1 at $DIR/lower_intrinsics.rs:46:15: 46:16
-        scope 2 (inlined std::mem::size_of::<()>) { // at $DIR/lower_intrinsics.rs:45:8: 45:32
+    let mut _0: ();                      // return place in scope 0 at $DIR/lower_intrinsics_e2e.rs:+0:17: +0:17
+    let mut _1: ();                      // in scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:16: +1:18
+    scope 1 (inlined f_dispatch::<()>) { // at $DIR/lower_intrinsics_e2e.rs:9:5: 9:19
+        debug t => _1;                   // in scope 1 at $DIR/lower_intrinsics_e2e.rs:19:22: 19:23
+        let _2: ();                      // in scope 1 at $DIR/lower_intrinsics_e2e.rs:21:9: 21:17
+        let mut _3: ();                  // in scope 1 at $DIR/lower_intrinsics_e2e.rs:21:15: 21:16
+        scope 2 (inlined std::mem::size_of::<()>) { // at $DIR/lower_intrinsics_e2e.rs:20:8: 20:32
         }
     }
 
     bb0: {
-        StorageLive(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+1:16: +1:18
-        StorageLive(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:46:9: 46:17
-        StorageLive(_3);                 // scope 1 at $DIR/lower_intrinsics.rs:46:15: 46:16
-        _2 = f_zst::<()>(move _3) -> bb1; // scope 1 at $DIR/lower_intrinsics.rs:46:9: 46:17
+        StorageLive(_1);                 // scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:16: +1:18
+        StorageLive(_2);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:21:9: 21:17
+        StorageLive(_3);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:21:15: 21:16
+        _2 = f_zst::<()>(move _3) -> bb1; // scope 1 at $DIR/lower_intrinsics_e2e.rs:21:9: 21:17
                                          // mir::Constant
-                                         // + span: $DIR/lower_intrinsics.rs:46:9: 46:14
+                                         // + span: $DIR/lower_intrinsics_e2e.rs:21:9: 21:14
                                          // + literal: Const { ty: fn(()) {f_zst::<()>}, val: Value(<ZST>) }
     }
 
     bb1: {
-        StorageDead(_3);                 // scope 1 at $DIR/lower_intrinsics.rs:46:16: 46:17
-        StorageDead(_2);                 // scope 1 at $DIR/lower_intrinsics.rs:46:17: 46:18
-        StorageDead(_1);                 // scope 0 at $DIR/lower_intrinsics.rs:+1:18: +1:19
-        return;                          // scope 0 at $DIR/lower_intrinsics.rs:+2:2: +2:2
+        StorageDead(_3);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:21:16: 21:17
+        StorageDead(_2);                 // scope 1 at $DIR/lower_intrinsics_e2e.rs:21:17: 21:18
+        StorageDead(_1);                 // scope 0 at $DIR/lower_intrinsics_e2e.rs:+1:18: +1:19
+        return;                          // scope 0 at $DIR/lower_intrinsics_e2e.rs:+2:2: +2:2
     }
 }
diff --git a/src/test/mir-opt/lower_intrinsics_e2e.rs b/src/test/mir-opt/lower_intrinsics_e2e.rs
new file mode 100644
index 000000000000..872ef59b0818
--- /dev/null
+++ b/src/test/mir-opt/lower_intrinsics_e2e.rs
@@ -0,0 +1,32 @@
+// Checks that we do not have any branches in the MIR for the two tested functions.
+
+// compile-flags: -Cpanic=abort
+#![feature(core_intrinsics)]
+#![crate_type = "lib"]
+
+// EMIT_MIR lower_intrinsics_e2e.f_unit.PreCodegen.after.mir
+pub fn f_unit() {
+    f_dispatch(());
+}
+
+
+// EMIT_MIR lower_intrinsics_e2e.f_u64.PreCodegen.after.mir
+pub fn f_u64() {
+    f_dispatch(0u64);
+}
+
+#[inline(always)]
+pub fn f_dispatch<T>(t: T) {
+    if std::mem::size_of::<T>() == 0 {
+        f_zst(t);
+    } else {
+        f_non_zst(t);
+    }
+}
+
+#[inline(never)]
+pub fn f_zst<T>(_t: T) {
+}
+
+#[inline(never)]
+pub fn f_non_zst<T>(_t: T) {}
diff --git a/src/test/mir-opt/lower_slice_len.bound.LowerSliceLenCalls.diff b/src/test/mir-opt/lower_slice_len.bound.LowerSliceLenCalls.diff
index 46fccba56f7c..5f5d6e68fdc1 100644
--- a/src/test/mir-opt/lower_slice_len.bound.LowerSliceLenCalls.diff
+++ b/src/test/mir-opt/lower_slice_len.bound.LowerSliceLenCalls.diff
@@ -23,7 +23,7 @@
 -         _5 = core::slice::<impl [u8]>::len(move _6) -> bb1; // scope 0 at $DIR/lower_slice_len.rs:+1:16: +1:27
 -                                          // mir::Constant
 -                                          // + span: $DIR/lower_slice_len.rs:5:22: 5:25
--                                          // + literal: Const { ty: for<'r> fn(&'r [u8]) -> usize {core::slice::<impl [u8]>::len}, val: Value(<ZST>) }
+-                                          // + literal: Const { ty: for<'a> fn(&'a [u8]) -> usize {core::slice::<impl [u8]>::len}, val: Value(<ZST>) }
 +         _5 = Len((*_6));                 // scope 0 at $DIR/lower_slice_len.rs:+1:16: +1:27
 +         goto -> bb1;                     // scope 0 at $DIR/lower_slice_len.rs:+1:16: +1:27
       }
diff --git a/src/test/mir-opt/match_false_edges.full_tested_match.PromoteTemps.after.mir b/src/test/mir-opt/match_false_edges.full_tested_match.PromoteTemps.after.mir
index c05ed00f7539..b193a8d76fcb 100644
--- a/src/test/mir-opt/match_false_edges.full_tested_match.PromoteTemps.after.mir
+++ b/src/test/mir-opt/match_false_edges.full_tested_match.PromoteTemps.after.mir
@@ -51,7 +51,7 @@ fn full_tested_match() -> () {
 
     bb5: {
         StorageLive(_6);                 // scope 0 at $DIR/match_false_edges.rs:+2:14: +2:15
-        _11 = const full_tested_match::promoted[0]; // scope 0 at $DIR/match_false_edges.rs:+2:14: +2:15
+        _11 = const _;                   // scope 0 at $DIR/match_false_edges.rs:+2:14: +2:15
                                          // mir::Constant
                                          // + span: $DIR/match_false_edges.rs:14:14: 14:15
                                          // + literal: Const { ty: &Option<i32>, val: Unevaluated(full_tested_match, [], Some(promoted[0])) }
diff --git a/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.64bit.diff b/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.64bit.diff
deleted file mode 100644
index 2005c10efa93..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.64bit.diff
+++ /dev/null
@@ -1,88 +0,0 @@
-- // MIR for `bar` before MatchBranchSimplification
-+ // MIR for `bar` after MatchBranchSimplification
-  
-  fn bar(_1: i32) -> (bool, bool, bool, bool) {
-      debug i => _1;                       // in scope 0 at $DIR/matches_reduce_branches.rs:+0:8: +0:9
-      let mut _0: (bool, bool, bool, bool); // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:19: +0:43
-      let _2: bool;                        // in scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:10
-      let _6: ();                          // in scope 0 at $DIR/matches_reduce_branches.rs:+6:5: +21:6
-      let mut _7: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+23:6: +23:7
-      let mut _8: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+23:9: +23:10
-      let mut _9: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+23:12: +23:13
-      let mut _10: bool;                   // in scope 0 at $DIR/matches_reduce_branches.rs:+23:15: +23:16
-+     let mut _11: i32;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+6:5: +6:12
-      scope 1 {
-          debug a => _2;                   // in scope 1 at $DIR/matches_reduce_branches.rs:+1:9: +1:10
-          let _3: bool;                    // in scope 1 at $DIR/matches_reduce_branches.rs:+2:9: +2:10
-          scope 2 {
-              debug b => _3;               // in scope 2 at $DIR/matches_reduce_branches.rs:+2:9: +2:10
-              let _4: bool;                // in scope 2 at $DIR/matches_reduce_branches.rs:+3:9: +3:10
-              scope 3 {
-                  debug c => _4;           // in scope 3 at $DIR/matches_reduce_branches.rs:+3:9: +3:10
-                  let _5: bool;            // in scope 3 at $DIR/matches_reduce_branches.rs:+4:9: +4:10
-                  scope 4 {
-                      debug d => _5;       // in scope 4 at $DIR/matches_reduce_branches.rs:+4:9: +4:10
-                  }
-              }
-          }
-      }
-  
-      bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:10
-          StorageLive(_3);                 // scope 1 at $DIR/matches_reduce_branches.rs:+2:9: +2:10
-          StorageLive(_4);                 // scope 2 at $DIR/matches_reduce_branches.rs:+3:9: +3:10
-          StorageLive(_5);                 // scope 3 at $DIR/matches_reduce_branches.rs:+4:9: +4:10
-          StorageLive(_6);                 // scope 4 at $DIR/matches_reduce_branches.rs:+6:5: +21:6
--         switchInt(_1) -> [7_i32: bb2, otherwise: bb1]; // scope 4 at $DIR/matches_reduce_branches.rs:+6:5: +6:12
--     }
-- 
--     bb1: {
--         _2 = const true;                 // scope 4 at $DIR/matches_reduce_branches.rs:+15:13: +15:21
--         _3 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+16:13: +16:22
--         _4 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+17:13: +17:22
--         _5 = const true;                 // scope 4 at $DIR/matches_reduce_branches.rs:+18:13: +18:21
--         nop;                             // scope 4 at $DIR/matches_reduce_branches.rs:+19:13: +19:15
--         goto -> bb3;                     // scope 4 at $DIR/matches_reduce_branches.rs:+19:13: +19:15
--     }
-- 
--     bb2: {
--         _2 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+8:13: +8:22
--         _3 = const true;                 // scope 4 at $DIR/matches_reduce_branches.rs:+9:13: +9:21
-+         StorageLive(_11);                // scope 4 at $DIR/matches_reduce_branches.rs:+6:5: +6:12
-+         _11 = _1;                        // scope 4 at $DIR/matches_reduce_branches.rs:+6:5: +6:12
-+         _2 = Ne(_11, const 7_i32);       // scope 4 at $DIR/matches_reduce_branches.rs:+8:13: +8:22
-+         _3 = Eq(_11, const 7_i32);       // scope 4 at $DIR/matches_reduce_branches.rs:+9:13: +9:21
-          _4 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+10:13: +10:22
-          _5 = const true;                 // scope 4 at $DIR/matches_reduce_branches.rs:+11:13: +11:21
--         nop;                             // scope 4 at $DIR/matches_reduce_branches.rs:+12:13: +12:15
--         goto -> bb3;                     // scope 4 at $DIR/matches_reduce_branches.rs:+12:13: +12:15
--     }
-- 
--     bb3: {
-+         StorageDead(_11);                // scope 4 at $DIR/matches_reduce_branches.rs:+6:5: +6:12
-          StorageDead(_6);                 // scope 4 at $DIR/matches_reduce_branches.rs:+21:6: +21:7
-          StorageLive(_7);                 // scope 4 at $DIR/matches_reduce_branches.rs:+23:6: +23:7
-          _7 = _2;                         // scope 4 at $DIR/matches_reduce_branches.rs:+23:6: +23:7
-          StorageLive(_8);                 // scope 4 at $DIR/matches_reduce_branches.rs:+23:9: +23:10
-          _8 = _3;                         // scope 4 at $DIR/matches_reduce_branches.rs:+23:9: +23:10
-          StorageLive(_9);                 // scope 4 at $DIR/matches_reduce_branches.rs:+23:12: +23:13
-          _9 = _4;                         // scope 4 at $DIR/matches_reduce_branches.rs:+23:12: +23:13
-          StorageLive(_10);                // scope 4 at $DIR/matches_reduce_branches.rs:+23:15: +23:16
-          _10 = _5;                        // scope 4 at $DIR/matches_reduce_branches.rs:+23:15: +23:16
-          Deinit(_0);                      // scope 4 at $DIR/matches_reduce_branches.rs:+23:5: +23:17
-          (_0.0: bool) = move _7;          // scope 4 at $DIR/matches_reduce_branches.rs:+23:5: +23:17
-          (_0.1: bool) = move _8;          // scope 4 at $DIR/matches_reduce_branches.rs:+23:5: +23:17
-          (_0.2: bool) = move _9;          // scope 4 at $DIR/matches_reduce_branches.rs:+23:5: +23:17
-          (_0.3: bool) = move _10;         // scope 4 at $DIR/matches_reduce_branches.rs:+23:5: +23:17
-          StorageDead(_10);                // scope 4 at $DIR/matches_reduce_branches.rs:+23:16: +23:17
-          StorageDead(_9);                 // scope 4 at $DIR/matches_reduce_branches.rs:+23:16: +23:17
-          StorageDead(_8);                 // scope 4 at $DIR/matches_reduce_branches.rs:+23:16: +23:17
-          StorageDead(_7);                 // scope 4 at $DIR/matches_reduce_branches.rs:+23:16: +23:17
-          StorageDead(_5);                 // scope 3 at $DIR/matches_reduce_branches.rs:+24:1: +24:2
-          StorageDead(_4);                 // scope 2 at $DIR/matches_reduce_branches.rs:+24:1: +24:2
-          StorageDead(_3);                 // scope 1 at $DIR/matches_reduce_branches.rs:+24:1: +24:2
-          StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+24:1: +24:2
-          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+24:2: +24:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.32bit.diff b/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.diff
similarity index 98%
rename from src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.32bit.diff
rename to src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.diff
index 2005c10efa93..f9eeb1ea5b96 100644
--- a/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.32bit.diff
+++ b/src/test/mir-opt/matches_reduce_branches.bar.MatchBranchSimplification.diff
@@ -41,7 +41,7 @@
 -         _3 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+16:13: +16:22
 -         _4 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+17:13: +17:22
 -         _5 = const true;                 // scope 4 at $DIR/matches_reduce_branches.rs:+18:13: +18:21
--         nop;                             // scope 4 at $DIR/matches_reduce_branches.rs:+19:13: +19:15
+-         Deinit(_6);                      // scope 4 at $DIR/matches_reduce_branches.rs:+19:13: +19:15
 -         goto -> bb3;                     // scope 4 at $DIR/matches_reduce_branches.rs:+19:13: +19:15
 -     }
 - 
@@ -54,7 +54,7 @@
 +         _3 = Eq(_11, const 7_i32);       // scope 4 at $DIR/matches_reduce_branches.rs:+9:13: +9:21
           _4 = const false;                // scope 4 at $DIR/matches_reduce_branches.rs:+10:13: +10:22
           _5 = const true;                 // scope 4 at $DIR/matches_reduce_branches.rs:+11:13: +11:21
--         nop;                             // scope 4 at $DIR/matches_reduce_branches.rs:+12:13: +12:15
+          Deinit(_6);                      // scope 4 at $DIR/matches_reduce_branches.rs:+12:13: +12:15
 -         goto -> bb3;                     // scope 4 at $DIR/matches_reduce_branches.rs:+12:13: +12:15
 -     }
 - 
diff --git a/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.32bit.diff b/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.32bit.diff
deleted file mode 100644
index b7862e5678f2..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.32bit.diff
+++ /dev/null
@@ -1,30 +0,0 @@
-- // MIR for `foo` before MatchBranchSimplification
-+ // MIR for `foo` after MatchBranchSimplification
-  
-  fn foo(_1: Option<()>) -> () {
-      debug bar => _1;                     // in scope 0 at $DIR/matches_reduce_branches.rs:+0:8: +0:11
-      let mut _0: ();                      // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:25
-      let mut _2: isize;                   // in scope 0 at $DIR/matches_reduce_branches.rs:+1:22: +1:26
-+     let mut _3: isize;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/matches_reduce_branches.rs:+1:17: +1:20
--         switchInt(move _2) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
--     }
-- 
--     bb1: {
--         goto -> bb3;                     // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
--     }
-- 
--     bb2: {
--         goto -> bb3;                     // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
--     }
-- 
--     bb3: {
-+         StorageLive(_3);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-+         _3 = move _2;                    // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-+         StorageDead(_3);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+4:2: +4:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.64bit.diff b/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.64bit.diff
deleted file mode 100644
index b7862e5678f2..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.64bit.diff
+++ /dev/null
@@ -1,30 +0,0 @@
-- // MIR for `foo` before MatchBranchSimplification
-+ // MIR for `foo` after MatchBranchSimplification
-  
-  fn foo(_1: Option<()>) -> () {
-      debug bar => _1;                     // in scope 0 at $DIR/matches_reduce_branches.rs:+0:8: +0:11
-      let mut _0: ();                      // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:25
-      let mut _2: isize;                   // in scope 0 at $DIR/matches_reduce_branches.rs:+1:22: +1:26
-+     let mut _3: isize;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/matches_reduce_branches.rs:+1:17: +1:20
--         switchInt(move _2) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
--     }
-- 
--     bb1: {
--         goto -> bb3;                     // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
--     }
-- 
--     bb2: {
--         goto -> bb3;                     // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
--     }
-- 
--     bb3: {
-+         StorageLive(_3);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-+         _3 = move _2;                    // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-+         StorageDead(_3);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+4:2: +4:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff b/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff
new file mode 100644
index 000000000000..0b40b3be8bdd
--- /dev/null
+++ b/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff
@@ -0,0 +1,55 @@
+- // MIR for `foo` before MatchBranchSimplification
++ // MIR for `foo` after MatchBranchSimplification
+  
+  fn foo(_1: Option<()>) -> () {
+      debug bar => _1;                     // in scope 0 at $DIR/matches_reduce_branches.rs:+0:8: +0:11
+      let mut _0: ();                      // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:25
+      let mut _2: bool;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _3: isize;                   // in scope 0 at $DIR/matches_reduce_branches.rs:+1:22: +1:26
++     let mut _4: isize;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+  
+      bb0: {
+          StorageLive(_2);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _3 = discriminant(_1);           // scope 0 at $DIR/matches_reduce_branches.rs:+1:17: +1:20
+-         switchInt(move _3) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
++         StorageLive(_4);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
++         _4 = move _3;                    // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
++         _2 = Eq(_4, const 0_isize);      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
++         StorageDead(_4);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
++         switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      }
+  
+      bb1: {
+-         _2 = const false;                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+-         goto -> bb3;                     // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+-     }
+- 
+-     bb2: {
+-         _2 = const true;                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+-         goto -> bb3;                     // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+-     }
+- 
+-     bb3: {
+-         switchInt(move _2) -> [false: bb5, otherwise: bb4]; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+-     }
+- 
+-     bb4: {
+          Deinit(_0);                      // scope 0 at $DIR/matches_reduce_branches.rs:+2:9: +2:11
+-         goto -> bb6;                     // scope 0 at $DIR/matches_reduce_branches.rs:+1:5: +3:6
++         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+1:5: +3:6
+      }
+  
+-     bb5: {
++     bb2: {
+          _0 = const ();                   // scope 0 at $DIR/matches_reduce_branches.rs:+3:6: +3:6
+-         goto -> bb6;                     // scope 0 at $DIR/matches_reduce_branches.rs:+1:5: +3:6
++         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+1:5: +3:6
+      }
+  
+-     bb6: {
++     bb3: {
+          StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+3:5: +3:6
+          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+4:2: +4:2
+      }
+  }
+  
diff --git a/src/test/mir-opt/matches_reduce_branches.foo.PreCodegen.before.32bit.mir b/src/test/mir-opt/matches_reduce_branches.foo.PreCodegen.before.32bit.mir
deleted file mode 100644
index a36ec8de4a39..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.foo.PreCodegen.before.32bit.mir
+++ /dev/null
@@ -1,10 +0,0 @@
-// MIR for `foo` before PreCodegen
-
-fn foo(_1: Option<()>) -> () {
-    debug bar => _1;                     // in scope 0 at $DIR/matches_reduce_branches.rs:+0:8: +0:11
-    let mut _0: ();                      // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:25
-
-    bb0: {
-        return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+4:2: +4:2
-    }
-}
diff --git a/src/test/mir-opt/matches_reduce_branches.foo.PreCodegen.before.64bit.mir b/src/test/mir-opt/matches_reduce_branches.foo.PreCodegen.before.64bit.mir
deleted file mode 100644
index a36ec8de4a39..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.foo.PreCodegen.before.64bit.mir
+++ /dev/null
@@ -1,10 +0,0 @@
-// MIR for `foo` before PreCodegen
-
-fn foo(_1: Option<()>) -> () {
-    debug bar => _1;                     // in scope 0 at $DIR/matches_reduce_branches.rs:+0:8: +0:11
-    let mut _0: ();                      // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:25
-
-    bb0: {
-        return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+4:2: +4:2
-    }
-}
diff --git a/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.32bit.diff b/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.32bit.diff
deleted file mode 100644
index 672c6b34e94b..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.32bit.diff
+++ /dev/null
@@ -1,42 +0,0 @@
-- // MIR for `match_nested_if` before MatchBranchSimplification
-+ // MIR for `match_nested_if` after MatchBranchSimplification
-  
-  fn match_nested_if() -> bool {
-      let mut _0: bool;                    // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:29
-      let _1: bool;                        // in scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
-      let mut _2: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-+     let mut _3: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-      scope 1 {
-          debug val => _1;                 // in scope 1 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
-          StorageLive(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-          _2 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
--         switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
--     }
-- 
--     bb1: {
-+         StorageLive(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-+         _3 = move _2;                    // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-          StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:51: +2:52
--         _1 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+8:13: +8:17
--         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+8:13: +8:17
--     }
-- 
--     bb2: {
--         StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:51: +2:52
--         _1 = const false;                // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
--         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
--     }
-- 
--     bb3: {
-+         _1 = Ne(_3, const false);        // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
-+         StorageDead(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-          _0 = _1;                         // scope 1 at $DIR/matches_reduce_branches.rs:+12:5: +12:8
-          StorageDead(_1);                 // scope 0 at $DIR/matches_reduce_branches.rs:+13:1: +13:2
-          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+13:2: +13:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.64bit.diff b/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.64bit.diff
deleted file mode 100644
index 672c6b34e94b..000000000000
--- a/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.64bit.diff
+++ /dev/null
@@ -1,42 +0,0 @@
-- // MIR for `match_nested_if` before MatchBranchSimplification
-+ // MIR for `match_nested_if` after MatchBranchSimplification
-  
-  fn match_nested_if() -> bool {
-      let mut _0: bool;                    // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:29
-      let _1: bool;                        // in scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
-      let mut _2: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-+     let mut _3: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-      scope 1 {
-          debug val => _1;                 // in scope 1 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
-          StorageLive(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-          _2 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
--         switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
--     }
-- 
--     bb1: {
-+         StorageLive(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-+         _3 = move _2;                    // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-          StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:51: +2:52
--         _1 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+8:13: +8:17
--         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+8:13: +8:17
--     }
-- 
--     bb2: {
--         StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:51: +2:52
--         _1 = const false;                // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
--         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
--     }
-- 
--     bb3: {
-+         _1 = Ne(_3, const false);        // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
-+         StorageDead(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
-          _0 = _1;                         // scope 1 at $DIR/matches_reduce_branches.rs:+12:5: +12:8
-          StorageDead(_1);                 // scope 0 at $DIR/matches_reduce_branches.rs:+13:1: +13:2
-          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+13:2: +13:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.diff b/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.diff
new file mode 100644
index 000000000000..b8c7722cd371
--- /dev/null
+++ b/src/test/mir-opt/matches_reduce_branches.match_nested_if.MatchBranchSimplification.diff
@@ -0,0 +1,113 @@
+- // MIR for `match_nested_if` before MatchBranchSimplification
++ // MIR for `match_nested_if` after MatchBranchSimplification
+  
+  fn match_nested_if() -> bool {
+      let mut _0: bool;                    // return place in scope 0 at $DIR/matches_reduce_branches.rs:+0:25: +0:29
+      let _1: bool;                        // in scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
+      let mut _2: ();                      // in scope 0 at $DIR/matches_reduce_branches.rs:+1:21: +1:23
+      let mut _3: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+      let mut _4: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
+      let mut _5: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
+      let mut _6: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
++     let mut _7: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
++     let mut _8: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
++     let mut _9: bool;                    // in scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
++     let mut _10: bool;                   // in scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+      scope 1 {
+          debug val => _1;                 // in scope 1 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
+      }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 0 at $DIR/matches_reduce_branches.rs:+1:9: +1:12
+          StorageLive(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+1:21: +1:23
+          Deinit(_2);                      // scope 0 at $DIR/matches_reduce_branches.rs:+1:21: +1:23
+          StorageLive(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+          StorageLive(_4);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
+          StorageLive(_5);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
+          StorageLive(_6);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
+          _6 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
+-         switchInt(move _6) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
+-     }
+- 
+-     bb1: {
+-         _5 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:31: +2:35
+-         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
+-     }
+- 
+-     bb2: {
+-         _5 = const false;                // scope 0 at $DIR/matches_reduce_branches.rs:+2:45: +2:50
+-         goto -> bb3;                     // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
+-     }
+- 
+-     bb3: {
++         StorageLive(_7);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
++         _7 = move _6;                    // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
++         _5 = Ne(_7, const false);        // scope 0 at $DIR/matches_reduce_branches.rs:+2:45: +2:50
++         StorageDead(_7);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:24: +2:28
+          StorageDead(_6);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:51: +2:52
+-         switchInt(move _5) -> [false: bb5, otherwise: bb4]; // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
+-     }
+- 
+-     bb4: {
+-         _4 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:55: +2:59
+-         goto -> bb6;                     // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
+-     }
+- 
+-     bb5: {
+-         _4 = const false;                // scope 0 at $DIR/matches_reduce_branches.rs:+2:69: +2:74
+-         goto -> bb6;                     // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
+-     }
+- 
+-     bb6: {
++         StorageLive(_8);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
++         _8 = move _5;                    // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
++         _4 = Ne(_8, const false);        // scope 0 at $DIR/matches_reduce_branches.rs:+2:69: +2:74
++         StorageDead(_8);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:21: +2:52
+          StorageDead(_5);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:75: +2:76
+-         switchInt(move _4) -> [false: bb8, otherwise: bb7]; // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
+-     }
+- 
+-     bb7: {
+-         _3 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+3:13: +3:17
+-         goto -> bb9;                     // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+-     }
+- 
+-     bb8: {
+-         _3 = const false;                // scope 0 at $DIR/matches_reduce_branches.rs:+5:13: +5:18
+-         goto -> bb9;                     // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+-     }
+- 
+-     bb9: {
+-         switchInt(move _3) -> [false: bb11, otherwise: bb10]; // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+-     }
+- 
+-     bb10: {
++         StorageLive(_9);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
++         _9 = move _4;                    // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
++         _3 = Ne(_9, const false);        // scope 0 at $DIR/matches_reduce_branches.rs:+5:13: +5:18
++         StorageDead(_9);                 // scope 0 at $DIR/matches_reduce_branches.rs:+2:18: +2:76
++         StorageLive(_10);                // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
++         _10 = move _3;                   // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+          StorageDead(_4);                 // scope 0 at $DIR/matches_reduce_branches.rs:+6:9: +6:10
+          StorageDead(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+6:9: +6:10
+-         _1 = const true;                 // scope 0 at $DIR/matches_reduce_branches.rs:+8:13: +8:17
+-         goto -> bb12;                    // scope 0 at $DIR/matches_reduce_branches.rs:+8:13: +8:17
+-     }
+- 
+-     bb11: {
+-         StorageDead(_4);                 // scope 0 at $DIR/matches_reduce_branches.rs:+6:9: +6:10
+-         StorageDead(_3);                 // scope 0 at $DIR/matches_reduce_branches.rs:+6:9: +6:10
+-         _1 = const false;                // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
+-         goto -> bb12;                    // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
+-     }
+- 
+-     bb12: {
++         _1 = Ne(_10, const false);       // scope 0 at $DIR/matches_reduce_branches.rs:+10:14: +10:19
++         StorageDead(_10);                // scope 0 at $DIR/matches_reduce_branches.rs:+2:15: +6:10
+          StorageDead(_2);                 // scope 0 at $DIR/matches_reduce_branches.rs:+11:6: +11:7
+          _0 = _1;                         // scope 1 at $DIR/matches_reduce_branches.rs:+12:5: +12:8
+          StorageDead(_1);                 // scope 0 at $DIR/matches_reduce_branches.rs:+13:1: +13:2
+          return;                          // scope 0 at $DIR/matches_reduce_branches.rs:+13:2: +13:2
+      }
+  }
+  
diff --git a/src/test/mir-opt/matches_reduce_branches.rs b/src/test/mir-opt/matches_reduce_branches.rs
index 51be3884d48d..a81d5f7b4e8b 100644
--- a/src/test/mir-opt/matches_reduce_branches.rs
+++ b/src/test/mir-opt/matches_reduce_branches.rs
@@ -1,6 +1,7 @@
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+// unit-test: MatchBranchSimplification
+
+
 // EMIT_MIR matches_reduce_branches.foo.MatchBranchSimplification.diff
-// EMIT_MIR matches_reduce_branches.foo.PreCodegen.before.mir
 // EMIT_MIR matches_reduce_branches.bar.MatchBranchSimplification.diff
 // EMIT_MIR matches_reduce_branches.match_nested_if.MatchBranchSimplification.diff
 
diff --git a/src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.64bit.diff b/src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.64bit.diff
deleted file mode 100644
index 1b4dddc1d43a..000000000000
--- a/src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.64bit.diff
+++ /dev/null
@@ -1,32 +0,0 @@
-- // MIR for `exhaustive_match` before MatchBranchSimplification
-+ // MIR for `exhaustive_match` after MatchBranchSimplification
-  
-  fn exhaustive_match(_1: E) -> u8 {
-      debug e => _1;                       // in scope 0 at $DIR/matches_u8.rs:+0:25: +0:26
-      let mut _0: u8;                      // return place in scope 0 at $DIR/matches_u8.rs:+0:34: +0:36
-      let mut _2: isize;                   // in scope 0 at $DIR/matches_u8.rs:+2:9: +2:13
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/matches_u8.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/matches_u8.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          _0 = const 1_u8;                 // scope 0 at $DIR/matches_u8.rs:+3:17: +3:18
-          goto -> bb4;                     // scope 0 at $DIR/matches_u8.rs:+3:17: +3:18
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/matches_u8.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          _0 = const 0_u8;                 // scope 0 at $DIR/matches_u8.rs:+2:17: +2:18
-          goto -> bb4;                     // scope 0 at $DIR/matches_u8.rs:+2:17: +2:18
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/matches_u8.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.32bit.diff b/src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.diff
similarity index 100%
rename from src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.32bit.diff
rename to src/test/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.diff
diff --git a/src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.64bit.diff b/src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.64bit.diff
deleted file mode 100644
index 6e734852e1af..000000000000
--- a/src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.64bit.diff
+++ /dev/null
@@ -1,32 +0,0 @@
-- // MIR for `exhaustive_match_i8` before MatchBranchSimplification
-+ // MIR for `exhaustive_match_i8` after MatchBranchSimplification
-  
-  fn exhaustive_match_i8(_1: E) -> i8 {
-      debug e => _1;                       // in scope 0 at $DIR/matches_u8.rs:+0:28: +0:29
-      let mut _0: i8;                      // return place in scope 0 at $DIR/matches_u8.rs:+0:37: +0:39
-      let mut _2: isize;                   // in scope 0 at $DIR/matches_u8.rs:+2:9: +2:13
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/matches_u8.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/matches_u8.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          _0 = const 1_i8;                 // scope 0 at $DIR/matches_u8.rs:+3:17: +3:18
-          goto -> bb4;                     // scope 0 at $DIR/matches_u8.rs:+3:17: +3:18
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/matches_u8.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          _0 = const 0_i8;                 // scope 0 at $DIR/matches_u8.rs:+2:17: +2:18
-          goto -> bb4;                     // scope 0 at $DIR/matches_u8.rs:+2:17: +2:18
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/matches_u8.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.32bit.diff b/src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff
similarity index 100%
rename from src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.32bit.diff
rename to src/test/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff
diff --git a/src/test/mir-opt/matches_u8.rs b/src/test/mir-opt/matches_u8.rs
index 78373be48b68..422c3a95e8ef 100644
--- a/src/test/mir-opt/matches_u8.rs
+++ b/src/test/mir-opt/matches_u8.rs
@@ -1,4 +1,6 @@
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+// unit-test: MatchBranchSimplification
+
+
 // EMIT_MIR matches_u8.exhaustive_match.MatchBranchSimplification.diff
 // EMIT_MIR matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff
 
diff --git a/src/test/mir-opt/nll/named_lifetimes_basic.use_x.nll.0.mir b/src/test/mir-opt/nll/named_lifetimes_basic.use_x.nll.0.mir
index cbfdf8c5d563..0ab9d712d9f6 100644
--- a/src/test/mir-opt/nll/named_lifetimes_basic.use_x.nll.0.mir
+++ b/src/test/mir-opt/nll/named_lifetimes_basic.use_x.nll.0.mir
@@ -13,11 +13,10 @@
 | '_#2r | U0 | {bb0[0..=1], '_#2r}
 | '_#3r | U0 | {bb0[0..=1], '_#3r}
 | '_#4r | U0 | {bb0[0..=1], '_#4r}
-| '_#5r | U0 | {}
-| '_#6r | U0 | {bb0[0..=1], '_#1r}
-| '_#7r | U0 | {bb0[0..=1], '_#2r}
-| '_#8r | U0 | {bb0[0..=1], '_#1r}
-| '_#9r | U0 | {bb0[0..=1], '_#3r}
+| '_#5r | U0 | {bb0[0..=1], '_#1r}
+| '_#6r | U0 | {bb0[0..=1], '_#2r}
+| '_#7r | U0 | {bb0[0..=1], '_#1r}
+| '_#8r | U0 | {bb0[0..=1], '_#3r}
 |
 | Inference Constraints
 | '_#0r live at {bb0[0..=1]}
@@ -25,16 +24,16 @@
 | '_#2r live at {bb0[0..=1]}
 | '_#3r live at {bb0[0..=1]}
 | '_#4r live at {bb0[0..=1]}
-| '_#1r: '_#6r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:26: 12:27) ($DIR/named-lifetimes-basic.rs:12:26: 12:27 (#0)
-| '_#1r: '_#8r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:54: 12:55) ($DIR/named-lifetimes-basic.rs:12:54: 12:55 (#0)
-| '_#2r: '_#7r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:42: 12:43) ($DIR/named-lifetimes-basic.rs:12:42: 12:43 (#0)
-| '_#3r: '_#9r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:66: 12:67) ($DIR/named-lifetimes-basic.rs:12:66: 12:67 (#0)
-| '_#6r: '_#1r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:26: 12:27) ($DIR/named-lifetimes-basic.rs:12:26: 12:27 (#0)
-| '_#7r: '_#2r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:42: 12:43) ($DIR/named-lifetimes-basic.rs:12:42: 12:43 (#0)
-| '_#8r: '_#1r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:54: 12:55) ($DIR/named-lifetimes-basic.rs:12:54: 12:55 (#0)
-| '_#9r: '_#3r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:66: 12:67) ($DIR/named-lifetimes-basic.rs:12:66: 12:67 (#0)
+| '_#1r: '_#5r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:26: 12:27) ($DIR/named-lifetimes-basic.rs:12:26: 12:27 (#0)
+| '_#1r: '_#7r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:54: 12:55) ($DIR/named-lifetimes-basic.rs:12:54: 12:55 (#0)
+| '_#2r: '_#6r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:42: 12:43) ($DIR/named-lifetimes-basic.rs:12:42: 12:43 (#0)
+| '_#3r: '_#8r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:66: 12:67) ($DIR/named-lifetimes-basic.rs:12:66: 12:67 (#0)
+| '_#5r: '_#1r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:26: 12:27) ($DIR/named-lifetimes-basic.rs:12:26: 12:27 (#0)
+| '_#6r: '_#2r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:42: 12:43) ($DIR/named-lifetimes-basic.rs:12:42: 12:43 (#0)
+| '_#7r: '_#1r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:54: 12:55) ($DIR/named-lifetimes-basic.rs:12:54: 12:55 (#0)
+| '_#8r: '_#3r due to BoringNoLocation at All($DIR/named-lifetimes-basic.rs:12:66: 12:67) ($DIR/named-lifetimes-basic.rs:12:66: 12:67 (#0)
 |
-fn use_x(_1: &'_#6r mut i32, _2: &'_#7r u32, _3: &'_#8r u32, _4: &'_#9r u32) -> bool {
+fn use_x(_1: &'_#5r mut i32, _2: &'_#6r u32, _3: &'_#7r u32, _4: &'_#8r u32) -> bool {
     debug w => _1;                       // in scope 0 at $DIR/named-lifetimes-basic.rs:+0:26: +0:27
     debug x => _2;                       // in scope 0 at $DIR/named-lifetimes-basic.rs:+0:42: +0:43
     debug y => _3;                       // in scope 0 at $DIR/named-lifetimes-basic.rs:+0:54: +0:55
diff --git a/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir b/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir
index 55e7faf9ee47..36705d18e016 100644
--- a/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir
+++ b/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir
@@ -7,19 +7,18 @@
 | Inferred Region Values
 | '_#0r | U0 | {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0], '_#0r, '_#1r}
 | '_#1r | U0 | {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0], '_#1r}
-| '_#2r | U0 | {}
-| '_#3r | U0 | {bb1[0..=7], bb2[0..=2]}
-| '_#4r | U0 | {bb1[1..=7], bb2[0..=2]}
-| '_#5r | U0 | {bb1[4..=7], bb2[0..=2]}
+| '_#2r | U0 | {bb1[0..=7], bb2[0..=2]}
+| '_#3r | U0 | {bb1[1..=7], bb2[0..=2]}
+| '_#4r | U0 | {bb1[4..=7], bb2[0..=2]}
 |
 | Inference Constraints
 | '_#0r live at {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0]}
 | '_#1r live at {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0]}
-| '_#3r live at {bb1[0]}
-| '_#4r live at {bb1[1..=3]}
-| '_#5r live at {bb1[4..=7], bb2[0..=2]}
-| '_#3r: '_#4r due to Assignment at Single(bb1[0]) ($DIR/region-subtyping-basic.rs:18:13: 18:18 (#0)
-| '_#4r: '_#5r due to Assignment at Single(bb1[3]) ($DIR/region-subtyping-basic.rs:19:13: 19:14 (#0)
+| '_#2r live at {bb1[0]}
+| '_#3r live at {bb1[1..=3]}
+| '_#4r live at {bb1[4..=7], bb2[0..=2]}
+| '_#2r: '_#3r due to Assignment at Single(bb1[0]) ($DIR/region-subtyping-basic.rs:18:13: 18:18 (#0)
+| '_#3r: '_#4r due to Assignment at Single(bb1[3]) ($DIR/region-subtyping-basic.rs:19:13: 19:14 (#0)
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/region-subtyping-basic.rs:+0:11: +0:11
@@ -33,10 +32,10 @@ fn main() -> () {
     let _10: bool;                       // in scope 0 at $DIR/region-subtyping-basic.rs:+7:9: +7:18
     scope 1 {
         debug v => _1;                   // in scope 1 at $DIR/region-subtyping-basic.rs:+1:9: +1:14
-        let _2: &'_#4r usize;            // in scope 1 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
+        let _2: &'_#3r usize;            // in scope 1 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
         scope 2 {
             debug p => _2;               // in scope 2 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
-            let _6: &'_#5r usize;        // in scope 2 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
+            let _6: &'_#4r usize;        // in scope 2 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
             scope 3 {
                 debug q => _6;           // in scope 3 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
             }
@@ -56,7 +55,7 @@ fn main() -> () {
     }
 
     bb1: {
-        _2 = &'_#3r _1[_3];              // bb1[0]: scope 1 at $DIR/region-subtyping-basic.rs:+2:13: +2:18
+        _2 = &'_#2r _1[_3];              // bb1[0]: scope 1 at $DIR/region-subtyping-basic.rs:+2:13: +2:18
         FakeRead(ForLet(None), _2);      // bb1[1]: scope 1 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
         StorageLive(_6);                 // bb1[2]: scope 2 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
         _6 = _2;                         // bb1[3]: scope 2 at $DIR/region-subtyping-basic.rs:+3:13: +3:14
diff --git a/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir b/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir
index 2647c94335f8..4f6256a67f46 100644
--- a/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir
+++ b/src/test/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir
@@ -7,19 +7,18 @@
 | Inferred Region Values
 | '_#0r | U0 | {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0], '_#0r, '_#1r}
 | '_#1r | U0 | {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0], '_#1r}
-| '_#2r | U0 | {}
-| '_#3r | U0 | {bb1[0..=7], bb2[0..=2]}
-| '_#4r | U0 | {bb1[1..=7], bb2[0..=2]}
-| '_#5r | U0 | {bb1[4..=7], bb2[0..=2]}
+| '_#2r | U0 | {bb1[0..=7], bb2[0..=2]}
+| '_#3r | U0 | {bb1[1..=7], bb2[0..=2]}
+| '_#4r | U0 | {bb1[4..=7], bb2[0..=2]}
 |
 | Inference Constraints
 | '_#0r live at {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0]}
 | '_#1r live at {bb0[0..=8], bb1[0..=7], bb2[0..=3], bb3[0..=3], bb4[0..=1], bb5[0..=2], bb6[0..=5], bb7[0]}
-| '_#3r live at {bb1[0]}
-| '_#4r live at {bb1[1..=3]}
-| '_#5r live at {bb1[4..=7], bb2[0..=2]}
-| '_#3r: '_#4r due to Assignment at Single(bb1[0]) ($DIR/region-subtyping-basic.rs:18:13: 18:18 (#0)
-| '_#4r: '_#5r due to Assignment at Single(bb1[3]) ($DIR/region-subtyping-basic.rs:19:13: 19:14 (#0)
+| '_#2r live at {bb1[0]}
+| '_#3r live at {bb1[1..=3]}
+| '_#4r live at {bb1[4..=7], bb2[0..=2]}
+| '_#2r: '_#3r due to Assignment at Single(bb1[0]) ($DIR/region-subtyping-basic.rs:18:13: 18:18 (#0)
+| '_#3r: '_#4r due to Assignment at Single(bb1[3]) ($DIR/region-subtyping-basic.rs:19:13: 19:14 (#0)
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/region-subtyping-basic.rs:+0:11: +0:11
@@ -33,10 +32,10 @@ fn main() -> () {
     let _10: bool;                       // in scope 0 at $DIR/region-subtyping-basic.rs:+7:9: +7:18
     scope 1 {
         debug v => _1;                   // in scope 1 at $DIR/region-subtyping-basic.rs:+1:9: +1:14
-        let _2: &'_#4r usize;            // in scope 1 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
+        let _2: &'_#3r usize;            // in scope 1 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
         scope 2 {
             debug p => _2;               // in scope 2 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
-            let _6: &'_#5r usize;        // in scope 2 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
+            let _6: &'_#4r usize;        // in scope 2 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
             scope 3 {
                 debug q => _6;           // in scope 3 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
             }
@@ -56,7 +55,7 @@ fn main() -> () {
     }
 
     bb1: {
-        _2 = &'_#3r _1[_3];              // bb1[0]: scope 1 at $DIR/region-subtyping-basic.rs:+2:13: +2:18
+        _2 = &'_#2r _1[_3];              // bb1[0]: scope 1 at $DIR/region-subtyping-basic.rs:+2:13: +2:18
         FakeRead(ForLet(None), _2);      // bb1[1]: scope 1 at $DIR/region-subtyping-basic.rs:+2:9: +2:10
         StorageLive(_6);                 // bb1[2]: scope 2 at $DIR/region-subtyping-basic.rs:+3:9: +3:10
         _6 = _2;                         // bb1[3]: scope 2 at $DIR/region-subtyping-basic.rs:+3:13: +3:14
diff --git a/src/test/mir-opt/no_spurious_drop_after_call.main.ElaborateDrops.before.mir b/src/test/mir-opt/no_spurious_drop_after_call.main.ElaborateDrops.before.mir
index 25c6e3060069..963e7cde6567 100644
--- a/src/test/mir-opt/no_spurious_drop_after_call.main.ElaborateDrops.before.mir
+++ b/src/test/mir-opt/no_spurious_drop_after_call.main.ElaborateDrops.before.mir
@@ -20,7 +20,7 @@ fn main() -> () {
         _2 = <str as ToString>::to_string(move _3) -> bb1; // scope 0 at $DIR/no-spurious-drop-after-call.rs:+1:20: +1:34
                                          // mir::Constant
                                          // + span: $DIR/no-spurious-drop-after-call.rs:9:23: 9:32
-                                         // + literal: Const { ty: for<'r> fn(&'r str) -> String {<str as ToString>::to_string}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a str) -> String {<str as ToString>::to_string}, val: Value(<ZST>) }
     }
 
     bb1: {
diff --git a/src/test/mir-opt/nrvo_simple.nrvo.RenameReturnPlace.diff b/src/test/mir-opt/nrvo_simple.nrvo.RenameReturnPlace.diff
index 9e89bd9fb963..ce35f920bf62 100644
--- a/src/test/mir-opt/nrvo_simple.nrvo.RenameReturnPlace.diff
+++ b/src/test/mir-opt/nrvo_simple.nrvo.RenameReturnPlace.diff
@@ -1,13 +1,13 @@
 - // MIR for `nrvo` before RenameReturnPlace
 + // MIR for `nrvo` after RenameReturnPlace
   
-  fn nrvo(_1: for<'r> fn(&'r mut [u8; 1024])) -> [u8; 1024] {
+  fn nrvo(_1: for<'a> fn(&'a mut [u8; 1024])) -> [u8; 1024] {
       debug init => _1;                    // in scope 0 at $DIR/nrvo-simple.rs:+0:9: +0:13
 -     let mut _0: [u8; 1024];              // return place in scope 0 at $DIR/nrvo-simple.rs:+0:39: +0:49
 +     let mut _0: [u8; 1024];              // return place in scope 0 at $DIR/nrvo-simple.rs:+1:9: +1:16
       let mut _2: [u8; 1024];              // in scope 0 at $DIR/nrvo-simple.rs:+1:9: +1:16
       let _3: ();                          // in scope 0 at $DIR/nrvo-simple.rs:+2:5: +2:19
-      let mut _4: for<'r> fn(&'r mut [u8; 1024]); // in scope 0 at $DIR/nrvo-simple.rs:+2:5: +2:9
+      let mut _4: for<'a> fn(&'a mut [u8; 1024]); // in scope 0 at $DIR/nrvo-simple.rs:+2:5: +2:9
       let mut _5: &mut [u8; 1024];         // in scope 0 at $DIR/nrvo-simple.rs:+2:10: +2:18
       let mut _6: &mut [u8; 1024];         // in scope 0 at $DIR/nrvo-simple.rs:+2:10: +2:18
       scope 1 {
diff --git a/src/test/mir-opt/packed-struct-drop-aligned.rs b/src/test/mir-opt/packed-struct-drop-aligned.rs
index 6c2e265d5146..cb6524260908 100644
--- a/src/test/mir-opt/packed-struct-drop-aligned.rs
+++ b/src/test/mir-opt/packed-struct-drop-aligned.rs
@@ -1,6 +1,6 @@
 // ignore-wasm32-bare compiled with panic=abort by default
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
 fn main() {
     let mut x = Packed(Aligned(Droppy(0)));
diff --git a/src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.64bit.mir b/src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.64bit.mir
deleted file mode 100644
index f9ed1036f006..000000000000
--- a/src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.64bit.mir
+++ /dev/null
@@ -1,60 +0,0 @@
-// MIR for `main` after SimplifyCfg-elaborate-drops
-
-fn main() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/packed-struct-drop-aligned.rs:+0:11: +0:11
-    let mut _1: Packed;                  // in scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:9: +1:14
-    let mut _2: Aligned;                 // in scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:24: +1:42
-    let mut _3: Droppy;                  // in scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:32: +1:41
-    let mut _4: Aligned;                 // in scope 0 at $DIR/packed-struct-drop-aligned.rs:+2:11: +2:29
-    let mut _5: Droppy;                  // in scope 0 at $DIR/packed-struct-drop-aligned.rs:+2:19: +2:28
-    let mut _6: Aligned;                 // in scope 0 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-    scope 1 {
-        debug x => _1;                   // in scope 1 at $DIR/packed-struct-drop-aligned.rs:+1:9: +1:14
-    }
-
-    bb0: {
-        StorageLive(_1);                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:9: +1:14
-        StorageLive(_2);                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:24: +1:42
-        StorageLive(_3);                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:32: +1:41
-        Deinit(_3);                      // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:32: +1:41
-        (_3.0: usize) = const 0_usize;   // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:32: +1:41
-        Deinit(_2);                      // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:24: +1:42
-        (_2.0: Droppy) = move _3;        // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:24: +1:42
-        StorageDead(_3);                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:41: +1:42
-        Deinit(_1);                      // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:17: +1:43
-        (_1.0: Aligned) = move _2;       // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:17: +1:43
-        StorageDead(_2);                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+1:42: +1:43
-        StorageLive(_4);                 // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:11: +2:29
-        StorageLive(_5);                 // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:19: +2:28
-        Deinit(_5);                      // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:19: +2:28
-        (_5.0: usize) = const 0_usize;   // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:19: +2:28
-        Deinit(_4);                      // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:11: +2:29
-        (_4.0: Droppy) = move _5;        // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:11: +2:29
-        StorageDead(_5);                 // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:28: +2:29
-        StorageLive(_6);                 // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-        _6 = move (_1.0: Aligned);       // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-        drop(_6) -> [return: bb4, unwind: bb3]; // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-    }
-
-    bb1: {
-        StorageDead(_1);                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+3:1: +3:2
-        return;                          // scope 0 at $DIR/packed-struct-drop-aligned.rs:+3:2: +3:2
-    }
-
-    bb2 (cleanup): {
-        resume;                          // scope 0 at $DIR/packed-struct-drop-aligned.rs:+0:1: +3:2
-    }
-
-    bb3 (cleanup): {
-        (_1.0: Aligned) = move _4;       // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-        drop(_1) -> bb2;                 // scope 0 at $DIR/packed-struct-drop-aligned.rs:+3:1: +3:2
-    }
-
-    bb4: {
-        StorageDead(_6);                 // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-        (_1.0: Aligned) = move _4;       // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:5: +2:8
-        StorageDead(_4);                 // scope 1 at $DIR/packed-struct-drop-aligned.rs:+2:28: +2:29
-        _0 = const ();                   // scope 0 at $DIR/packed-struct-drop-aligned.rs:+0:11: +3:2
-        drop(_1) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/packed-struct-drop-aligned.rs:+3:1: +3:2
-    }
-}
diff --git a/src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.32bit.mir b/src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
similarity index 100%
rename from src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.32bit.mir
rename to src/test/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
diff --git a/src/test/mir-opt/remove_storage_markers.main.RemoveStorageMarkers.diff b/src/test/mir-opt/remove_storage_markers.main.RemoveStorageMarkers.diff
index 99667aabdaee..188aa5564906 100644
--- a/src/test/mir-opt/remove_storage_markers.main.RemoveStorageMarkers.diff
+++ b/src/test/mir-opt/remove_storage_markers.main.RemoveStorageMarkers.diff
@@ -57,7 +57,7 @@
           _7 = <std::ops::Range<i32> as Iterator>::next(move _8) -> bb3; // scope 2 at $DIR/remove_storage_markers.rs:+2:14: +2:19
                                            // mir::Constant
                                            // + span: $DIR/remove_storage_markers.rs:10:14: 10:19
-                                           // + literal: Const { ty: for<'r> fn(&'r mut std::ops::Range<i32>) -> Option<<std::ops::Range<i32> as Iterator>::Item> {<std::ops::Range<i32> as Iterator>::next}, val: Value(<ZST>) }
+                                           // + literal: Const { ty: for<'a> fn(&'a mut std::ops::Range<i32>) -> Option<<std::ops::Range<i32> as Iterator>::Item> {<std::ops::Range<i32> as Iterator>::next}, val: Value(<ZST>) }
       }
   
       bb3: {
diff --git a/src/test/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir b/src/test/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
index 8ea61533d073..fe57e32a7acc 100644
--- a/src/test/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
+++ b/src/test/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
@@ -29,7 +29,7 @@ fn array_casts() -> () {
     let _31: &usize;                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _32: &usize;                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let _33: &usize;                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _34: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _34: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     scope 1 {
         debug x => _1;                   // in scope 1 at $DIR/retag.rs:+1:9: +1:14
         let _2: *mut usize;              // in scope 1 at $DIR/retag.rs:+2:9: +2:10
@@ -121,7 +121,7 @@ fn array_casts() -> () {
         _14 = &_15;                      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         Retag(_14);                      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_18);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _35 = const array_casts::promoted[0]; // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _35 = const _;                   // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // + literal: Const { ty: &usize, val: Unevaluated(array_casts, [], Some(promoted[0])) }
@@ -180,7 +180,7 @@ fn array_casts() -> () {
         _28 = core::panicking::assert_failed::<usize, usize>(move _29, move _30, move _32, move _34); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r usize, &'s usize, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<usize, usize>}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a usize, &'b usize, Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<usize, usize>}, val: Value(<ZST>) }
     }
 
     bb4: {
diff --git a/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir b/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
index 84f674db2d15..cdc413c568f1 100644
--- a/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
+++ b/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
@@ -11,7 +11,7 @@ fn std::ptr::drop_in_place(_1: *mut Test) -> () {
         _3 = <Test as Drop>::drop(move _2) -> bb1; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r> fn(&'r mut Test) {<Test as Drop>::drop}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a mut Test) {<Test as Drop>::drop}, val: Value(<ZST>) }
     }
 
     bb1: {
diff --git a/src/test/mir-opt/retag.main-{closure#0}.SimplifyCfg-elaborate-drops.after.mir b/src/test/mir-opt/retag.main-{closure#0}.SimplifyCfg-elaborate-drops.after.mir
index d254a95e06be..96fc7e6493ab 100644
--- a/src/test/mir-opt/retag.main-{closure#0}.SimplifyCfg-elaborate-drops.after.mir
+++ b/src/test/mir-opt/retag.main-{closure#0}.SimplifyCfg-elaborate-drops.after.mir
@@ -3,20 +3,20 @@
 fn main::{closure#0}(_1: &[closure@main::{closure#0}], _2: &i32) -> &i32 {
     debug x => _2;                       // in scope 0 at $DIR/retag.rs:+0:32: +0:33
     let mut _0: &i32;                    // return place in scope 0 at $DIR/retag.rs:+0:44: +0:48
-    let _3: &i32;                        // in scope 0 at $DIR/retag.rs:42:13: 42:15
+    let _3: &i32;                        // in scope 0 at $DIR/retag.rs:+1:13: +1:15
     scope 1 {
-        debug _y => _3;                  // in scope 1 at $DIR/retag.rs:42:13: 42:15
+        debug _y => _3;                  // in scope 1 at $DIR/retag.rs:+1:13: +1:15
     }
 
     bb0: {
-        Retag([fn entry] _1);            // scope 0 at $DIR/retag.rs:+0:31: +0:48
+        Retag([fn entry] _1);            // scope 0 at $DIR/retag.rs:+0:31: +3:6
         Retag([fn entry] _2);            // scope 0 at $DIR/retag.rs:+0:32: +0:33
-        StorageLive(_3);                 // scope 0 at $DIR/retag.rs:42:13: 42:15
-        _3 = _2;                         // scope 0 at $DIR/retag.rs:42:18: 42:19
-        Retag(_3);                       // scope 0 at $DIR/retag.rs:42:18: 42:19
-        _0 = _2;                         // scope 1 at $DIR/retag.rs:43:9: 43:10
-        Retag(_0);                       // scope 1 at $DIR/retag.rs:43:9: 43:10
-        StorageDead(_3);                 // scope 0 at $DIR/retag.rs:44:5: 44:6
-        return;                          // scope 0 at $DIR/retag.rs:+0:48: +0:48
+        StorageLive(_3);                 // scope 0 at $DIR/retag.rs:+1:13: +1:15
+        _3 = _2;                         // scope 0 at $DIR/retag.rs:+1:18: +1:19
+        Retag(_3);                       // scope 0 at $DIR/retag.rs:+1:18: +1:19
+        _0 = &(*_2);                     // scope 1 at $DIR/retag.rs:+2:9: +2:10
+        Retag(_0);                       // scope 1 at $DIR/retag.rs:+2:9: +2:10
+        StorageDead(_3);                 // scope 0 at $DIR/retag.rs:+3:5: +3:6
+        return;                          // scope 0 at $DIR/retag.rs:+3:6: +3:6
     }
 }
diff --git a/src/test/mir-opt/retag.main.SimplifyCfg-elaborate-drops.after.mir b/src/test/mir-opt/retag.main.SimplifyCfg-elaborate-drops.after.mir
index e4a06554f1a6..81225b44ebf9 100644
--- a/src/test/mir-opt/retag.main.SimplifyCfg-elaborate-drops.after.mir
+++ b/src/test/mir-opt/retag.main.SimplifyCfg-elaborate-drops.after.mir
@@ -11,7 +11,7 @@ fn main() -> () {
     let mut _9: &mut i32;                // in scope 0 at $DIR/retag.rs:+4:19: +4:20
     let mut _12: *mut i32;               // in scope 0 at $DIR/retag.rs:+7:18: +7:29
     let mut _14: [closure@main::{closure#0}]; // in scope 0 at $DIR/retag.rs:+11:31: +14:6
-    let mut _16: for<'r> fn(&'r i32) -> &'r i32; // in scope 0 at $DIR/retag.rs:+15:14: +15:15
+    let mut _16: for<'a> fn(&'a i32) -> &'a i32; // in scope 0 at $DIR/retag.rs:+15:14: +15:15
     let mut _17: &i32;                   // in scope 0 at $DIR/retag.rs:+15:16: +15:18
     let _18: &i32;                       // in scope 0 at $DIR/retag.rs:+15:16: +15:18
     let _19: &i32;                       // in scope 0 at $DIR/retag.rs:+18:5: +18:24
@@ -25,7 +25,7 @@ fn main() -> () {
     scope 1 {
         debug x => _1;                   // in scope 1 at $DIR/retag.rs:+1:9: +1:14
         let _3: &mut i32;                // in scope 1 at $DIR/retag.rs:+3:13: +3:14
-        let _13: for<'r> fn(&'r i32) -> &'r i32; // in scope 1 at $DIR/retag.rs:+11:9: +11:10
+        let _13: for<'a> fn(&'a i32) -> &'a i32; // in scope 1 at $DIR/retag.rs:+11:9: +11:10
         scope 2 {
             debug v => _3;               // in scope 2 at $DIR/retag.rs:+3:13: +3:14
             let _8: &mut i32;            // in scope 2 at $DIR/retag.rs:+4:13: +4:14
@@ -75,7 +75,7 @@ fn main() -> () {
         _3 = Test::foo(move _4, move _6) -> [return: bb1, unwind: bb8]; // scope 1 at $DIR/retag.rs:+3:17: +3:36
                                          // mir::Constant
                                          // + span: $DIR/retag.rs:33:25: 33:28
-                                         // + literal: Const { ty: for<'r, 'x> fn(&'r Test, &'x mut i32) -> &'x mut i32 {Test::foo}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'x> fn(&'a Test, &'x mut i32) -> &'x mut i32 {Test::foo}, val: Value(<ZST>) }
     }
 
     bb1: {
@@ -114,7 +114,7 @@ fn main() -> () {
         StorageLive(_14);                // scope 1 at $DIR/retag.rs:+11:31: +14:6
         Deinit(_14);                     // scope 1 at $DIR/retag.rs:+11:31: +14:6
         Retag(_14);                      // scope 1 at $DIR/retag.rs:+11:31: +14:6
-        _13 = move _14 as for<'r> fn(&'r i32) -> &'r i32 (Pointer(ClosureFnPointer(Normal))); // scope 1 at $DIR/retag.rs:+11:31: +14:6
+        _13 = move _14 as for<'a> fn(&'a i32) -> &'a i32 (Pointer(ClosureFnPointer(Normal))); // scope 1 at $DIR/retag.rs:+11:31: +14:6
         StorageDead(_14);                // scope 1 at $DIR/retag.rs:+11:47: +11:48
         StorageLive(_15);                // scope 6 at $DIR/retag.rs:+15:9: +15:11
         StorageLive(_16);                // scope 6 at $DIR/retag.rs:+15:14: +15:15
@@ -142,7 +142,7 @@ fn main() -> () {
         Retag(_20);                      // scope 7 at $DIR/retag.rs:+18:5: +18:24
         StorageLive(_22);                // scope 7 at $DIR/retag.rs:+18:21: +18:23
         StorageLive(_23);                // scope 7 at $DIR/retag.rs:+18:21: +18:23
-        _28 = const main::promoted[0];   // scope 7 at $DIR/retag.rs:+18:21: +18:23
+        _28 = const _;                   // scope 7 at $DIR/retag.rs:+18:21: +18:23
                                          // mir::Constant
                                          // + span: $DIR/retag.rs:48:21: 48:23
                                          // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
@@ -154,7 +154,7 @@ fn main() -> () {
         _19 = Test::foo_shr(move _20, move _22) -> [return: bb4, unwind: bb7]; // scope 7 at $DIR/retag.rs:+18:5: +18:24
                                          // mir::Constant
                                          // + span: $DIR/retag.rs:48:13: 48:20
-                                         // + literal: Const { ty: for<'r, 'x> fn(&'r Test, &'x i32) -> &'x i32 {Test::foo_shr}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'x> fn(&'a Test, &'x i32) -> &'x i32 {Test::foo_shr}, val: Value(<ZST>) }
     }
 
     bb4: {
diff --git a/src/test/mir-opt/separate_const_switch.identity.ConstProp.diff b/src/test/mir-opt/separate_const_switch.identity.ConstProp.diff
deleted file mode 100644
index 28536dc28a72..000000000000
--- a/src/test/mir-opt/separate_const_switch.identity.ConstProp.diff
+++ /dev/null
@@ -1,146 +0,0 @@
-- // MIR for `identity` before ConstProp
-+ // MIR for `identity` after ConstProp
-  
-  fn identity(_1: Result<i32, i32>) -> Result<i32, i32> {
-      debug x => _1;                       // in scope 0 at $DIR/separate_const_switch.rs:+0:13: +0:14
-      let mut _0: std::result::Result<i32, i32>; // return place in scope 0 at $DIR/separate_const_switch.rs:+0:37: +0:53
-      let mut _2: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-      let mut _3: std::ops::ControlFlow<std::result::Result<std::convert::Infallible, i32>, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-      let mut _4: std::result::Result<i32, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
-      let mut _5: isize;                   // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-      let _6: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-      let mut _7: !;                       // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-      let mut _8: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-      let _9: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-      scope 1 {
-          debug residual => _6;            // in scope 1 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          scope 2 {
-              scope 8 (inlined #[track_caller] <Result<i32, i32> as FromResidual<Result<Infallible, i32>>>::from_residual) { // at $DIR/separate_const_switch.rs:29:8: 29:10
-                  debug residual => _8;    // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                  let _16: i32;            // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                  let mut _17: i32;        // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                  let mut _18: i32;        // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                  scope 9 {
-                      debug e => _16;      // in scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-                      scope 10 (inlined <i32 as From<i32>>::from) { // at $SRC_DIR/core/src/result.rs:LL:COL
-                          debug t => _18;  // in scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
-                      }
-                  }
-              }
-          }
-      }
-      scope 3 {
-          debug val => _9;                 // in scope 3 at $DIR/separate_const_switch.rs:+1:8: +1:10
-          scope 4 {
-          }
-      }
-      scope 5 (inlined <Result<i32, i32> as Try>::branch) { // at $DIR/separate_const_switch.rs:29:8: 29:10
-          debug self => _4;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          let mut _10: isize;              // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          let _11: i32;                    // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          let mut _12: i32;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          let _13: i32;                    // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          let mut _14: std::result::Result<std::convert::Infallible, i32>; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          let mut _15: i32;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          scope 6 {
-              debug v => _11;              // in scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          }
-          scope 7 {
-              debug e => _13;              // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          }
-      }
-  
-      bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-          StorageLive(_3);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-          StorageLive(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
-          _4 = _1;                         // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
-          _10 = discriminant(_4);          // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          switchInt(move _10) -> [0_isize: bb6, 1_isize: bb4, otherwise: bb5]; // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-      }
-  
-      bb1: {
-          StorageLive(_9);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-          _9 = ((_3 as Continue).0: i32);  // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-          _2 = _9;                         // scope 4 at $DIR/separate_const_switch.rs:+1:8: +1:10
-          StorageDead(_9);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          Deinit(_0);                      // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
-          ((_0 as Ok).0: i32) = move _2;   // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
-          discriminant(_0) = 0;            // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
-          StorageDead(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+1:10: +1:11
-          StorageDead(_3);                 // scope 0 at $DIR/separate_const_switch.rs:+2:1: +2:2
-          return;                          // scope 0 at $DIR/separate_const_switch.rs:+2:2: +2:2
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-      }
-  
-      bb3: {
-          StorageLive(_6);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          _6 = ((_3 as Break).0: std::result::Result<std::convert::Infallible, i32>); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          StorageLive(_8);                 // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          _8 = _6;                         // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          StorageLive(_16);                // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-          _16 = move ((_8 as Err).0: i32); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageLive(_17);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageLive(_18);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          _18 = move _16;                  // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          _17 = move _18;                  // scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
-          StorageDead(_18);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          Deinit(_0);                      // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          ((_0 as Err).0: i32) = move _17; // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          discriminant(_0) = 1;            // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_17);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_16);                // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_8);                 // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          StorageDead(_6);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-          StorageDead(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+1:10: +1:11
-          StorageDead(_3);                 // scope 0 at $DIR/separate_const_switch.rs:+2:1: +2:2
-          return;                          // scope 0 at $DIR/separate_const_switch.rs:+2:2: +2:2
-      }
-  
-      bb4: {
-          StorageLive(_13);                // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          _13 = move ((_4 as Err).0: i32); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageLive(_14);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageLive(_15);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          _15 = move _13;                  // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          Deinit(_14);                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          ((_14 as Err).0: i32) = move _15; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          discriminant(_14) = 1;           // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_15);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          Deinit(_3);                      // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          ((_3 as Break).0: std::result::Result<std::convert::Infallible, i32>) = move _14; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          discriminant(_3) = 1;            // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_14);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_13);                // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
--         _5 = discriminant(_3);           // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
--         switchInt(move _5) -> [0_isize: bb1, 1_isize: bb3, otherwise: bb2]; // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-+         _5 = const 1_isize;              // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-+         switchInt(const 1_isize) -> [0_isize: bb1, 1_isize: bb3, otherwise: bb2]; // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-      }
-  
-      bb5: {
-          unreachable;                     // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-      }
-  
-      bb6: {
-          StorageLive(_11);                // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          _11 = move ((_4 as Ok).0: i32);  // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageLive(_12);                // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          _12 = move _11;                  // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          Deinit(_3);                      // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          ((_3 as Continue).0: i32) = move _12; // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          discriminant(_3) = 0;            // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_12);                // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_11);                // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-          StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
--         _5 = discriminant(_3);           // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
--         switchInt(move _5) -> [0_isize: bb1, 1_isize: bb3, otherwise: bb2]; // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-+         _5 = const 0_isize;              // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-+         switchInt(const 0_isize) -> [0_isize: bb1, 1_isize: bb3, otherwise: bb2]; // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-      }
-  }
-  
diff --git a/src/test/mir-opt/separate_const_switch.identity.PreCodegen.after.mir b/src/test/mir-opt/separate_const_switch.identity.PreCodegen.after.mir
deleted file mode 100644
index df20f0ed36b6..000000000000
--- a/src/test/mir-opt/separate_const_switch.identity.PreCodegen.after.mir
+++ /dev/null
@@ -1,124 +0,0 @@
-// MIR for `identity` after PreCodegen
-
-fn identity(_1: Result<i32, i32>) -> Result<i32, i32> {
-    debug x => _1;                       // in scope 0 at $DIR/separate_const_switch.rs:+0:13: +0:14
-    let mut _0: std::result::Result<i32, i32>; // return place in scope 0 at $DIR/separate_const_switch.rs:+0:37: +0:53
-    let mut _2: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-    let mut _3: std::ops::ControlFlow<std::result::Result<std::convert::Infallible, i32>, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-    let mut _4: std::result::Result<i32, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
-    let _5: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-    let mut _6: std::result::Result<std::convert::Infallible, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-    let _7: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-    scope 1 {
-        debug residual => _5;            // in scope 1 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        scope 2 {
-            scope 8 (inlined #[track_caller] <Result<i32, i32> as FromResidual<Result<Infallible, i32>>>::from_residual) { // at $DIR/separate_const_switch.rs:29:8: 29:10
-                debug residual => _6;    // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                let _14: i32;            // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                let mut _15: i32;        // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                let mut _16: i32;        // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-                scope 9 {
-                    debug e => _14;      // in scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-                    scope 10 (inlined <i32 as From<i32>>::from) { // at $SRC_DIR/core/src/result.rs:LL:COL
-                        debug t => _16;  // in scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
-                    }
-                }
-            }
-        }
-    }
-    scope 3 {
-        debug val => _7;                 // in scope 3 at $DIR/separate_const_switch.rs:+1:8: +1:10
-        scope 4 {
-        }
-    }
-    scope 5 (inlined <Result<i32, i32> as Try>::branch) { // at $DIR/separate_const_switch.rs:29:8: 29:10
-        debug self => _4;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        let mut _8: isize;               // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        let _9: i32;                     // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        let mut _10: i32;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        let _11: i32;                    // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        let mut _12: std::result::Result<std::convert::Infallible, i32>; // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        let mut _13: i32;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        scope 6 {
-            debug v => _9;               // in scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        }
-        scope 7 {
-            debug e => _11;              // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        }
-    }
-
-    bb0: {
-        StorageLive(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-        StorageLive(_3);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-        StorageLive(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
-        _4 = _1;                         // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:9
-        _8 = discriminant(_4);           // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        switchInt(move _8) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-    }
-
-    bb1: {
-        StorageLive(_11);                // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        _11 = move ((_4 as Err).0: i32); // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageLive(_12);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageLive(_13);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        _13 = move _11;                  // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        Deinit(_12);                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        ((_12 as Err).0: i32) = move _13; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        discriminant(_12) = 1;           // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_13);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        Deinit(_3);                      // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        ((_3 as Break).0: std::result::Result<std::convert::Infallible, i32>) = move _12; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        discriminant(_3) = 1;            // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_12);                // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_11);                // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        StorageLive(_5);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        _5 = ((_3 as Break).0: std::result::Result<std::convert::Infallible, i32>); // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        StorageLive(_6);                 // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        _6 = _5;                         // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        StorageLive(_14);                // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-        _14 = move ((_6 as Err).0: i32); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageLive(_15);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageLive(_16);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        _16 = move _14;                  // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        _15 = move _16;                  // scope 10 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
-        StorageDead(_16);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        Deinit(_0);                      // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        ((_0 as Err).0: i32) = move _15; // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        discriminant(_0) = 1;            // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_15);                // scope 9 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_14);                // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_6);                 // scope 2 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        StorageDead(_5);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        StorageDead(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+1:10: +1:11
-        StorageDead(_3);                 // scope 0 at $DIR/separate_const_switch.rs:+2:1: +2:2
-        return;                          // scope 0 at $DIR/separate_const_switch.rs:+2:2: +2:2
-    }
-
-    bb2: {
-        unreachable;                     // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-    }
-
-    bb3: {
-        StorageLive(_9);                 // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        _9 = move ((_4 as Ok).0: i32);   // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageLive(_10);                // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        _10 = move _9;                   // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        Deinit(_3);                      // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        ((_3 as Continue).0: i32) = move _10; // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        discriminant(_3) = 0;            // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_10);                // scope 6 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_9);                 // scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
-        StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        StorageLive(_7);                 // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-        _7 = ((_3 as Continue).0: i32);  // scope 0 at $DIR/separate_const_switch.rs:+1:8: +1:10
-        _2 = _7;                         // scope 4 at $DIR/separate_const_switch.rs:+1:8: +1:10
-        StorageDead(_7);                 // scope 0 at $DIR/separate_const_switch.rs:+1:9: +1:10
-        Deinit(_0);                      // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
-        ((_0 as Ok).0: i32) = move _2;   // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
-        discriminant(_0) = 0;            // scope 0 at $DIR/separate_const_switch.rs:+1:5: +1:11
-        StorageDead(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+1:10: +1:11
-        StorageDead(_3);                 // scope 0 at $DIR/separate_const_switch.rs:+2:1: +2:2
-        return;                          // scope 0 at $DIR/separate_const_switch.rs:+2:2: +2:2
-    }
-}
diff --git a/src/test/mir-opt/separate_const_switch.identity.SeparateConstSwitch.diff b/src/test/mir-opt/separate_const_switch.identity.SeparateConstSwitch.diff
index b8c554d3ea6b..f25b3ce724be 100644
--- a/src/test/mir-opt/separate_const_switch.identity.SeparateConstSwitch.diff
+++ b/src/test/mir-opt/separate_const_switch.identity.SeparateConstSwitch.diff
@@ -15,7 +15,7 @@
       scope 1 {
           debug residual => _6;            // in scope 1 at $DIR/separate_const_switch.rs:+1:9: +1:10
           scope 2 {
-              scope 8 (inlined #[track_caller] <Result<i32, i32> as FromResidual<Result<Infallible, i32>>>::from_residual) { // at $DIR/separate_const_switch.rs:29:8: 29:10
+              scope 8 (inlined #[track_caller] <Result<i32, i32> as FromResidual<Result<Infallible, i32>>>::from_residual) { // at $DIR/separate_const_switch.rs:25:8: 25:10
                   debug residual => _8;    // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
                   let _16: i32;            // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
                   let mut _17: i32;        // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
@@ -34,7 +34,7 @@
           scope 4 {
           }
       }
-      scope 5 (inlined <Result<i32, i32> as Try>::branch) { // at $DIR/separate_const_switch.rs:29:8: 29:10
+      scope 5 (inlined <Result<i32, i32> as Try>::branch) { // at $DIR/separate_const_switch.rs:25:8: 25:10
           debug self => _4;                // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
           let mut _10: isize;              // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
           let _11: i32;                    // in scope 5 at $SRC_DIR/core/src/result.rs:LL:COL
diff --git a/src/test/mir-opt/separate_const_switch.rs b/src/test/mir-opt/separate_const_switch.rs
index 5d82acf4d609..c809e5629cc1 100644
--- a/src/test/mir-opt/separate_const_switch.rs
+++ b/src/test/mir-opt/separate_const_switch.rs
@@ -4,8 +4,6 @@
 use std::ops::ControlFlow;
 
 // EMIT_MIR separate_const_switch.too_complex.SeparateConstSwitch.diff
-// EMIT_MIR separate_const_switch.too_complex.ConstProp.diff
-// EMIT_MIR separate_const_switch.too_complex.PreCodegen.after.mir
 fn too_complex(x: Result<i32, usize>) -> Option<i32> {
     // The pass should break the outer match into
     // two blocks that only have one parent each.
@@ -23,8 +21,6 @@ fn too_complex(x: Result<i32, usize>) -> Option<i32> {
 }
 
 // EMIT_MIR separate_const_switch.identity.SeparateConstSwitch.diff
-// EMIT_MIR separate_const_switch.identity.ConstProp.diff
-// EMIT_MIR separate_const_switch.identity.PreCodegen.after.mir
 fn identity(x: Result<i32, i32>) -> Result<i32, i32> {
     Ok(x?)
 }
diff --git a/src/test/mir-opt/separate_const_switch.too_complex.ConstProp.diff b/src/test/mir-opt/separate_const_switch.too_complex.ConstProp.diff
deleted file mode 100644
index 28269165e1c2..000000000000
--- a/src/test/mir-opt/separate_const_switch.too_complex.ConstProp.diff
+++ /dev/null
@@ -1,103 +0,0 @@
-- // MIR for `too_complex` before ConstProp
-+ // MIR for `too_complex` after ConstProp
-  
-  fn too_complex(_1: Result<i32, usize>) -> Option<i32> {
-      debug x => _1;                       // in scope 0 at $DIR/separate_const_switch.rs:+0:16: +0:17
-      let mut _0: std::option::Option<i32>; // return place in scope 0 at $DIR/separate_const_switch.rs:+0:42: +0:53
-      let mut _2: std::ops::ControlFlow<usize, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-      let mut _3: isize;                   // in scope 0 at $DIR/separate_const_switch.rs:+7:13: +7:18
-      let _4: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
-      let mut _5: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:+7:44: +7:45
-      let _6: usize;                       // in scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
-      let mut _7: usize;                   // in scope 0 at $DIR/separate_const_switch.rs:+8:42: +8:43
-      let mut _8: isize;                   // in scope 0 at $DIR/separate_const_switch.rs:+11:9: +11:33
-      let _9: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
-      let mut _10: i32;                    // in scope 0 at $DIR/separate_const_switch.rs:+11:42: +11:43
-      let _11: usize;                      // in scope 0 at $DIR/separate_const_switch.rs:+12:28: +12:29
-      scope 1 {
-          debug v => _4;                   // in scope 1 at $DIR/separate_const_switch.rs:+7:16: +7:17
-      }
-      scope 2 {
-          debug r => _6;                   // in scope 2 at $DIR/separate_const_switch.rs:+8:17: +8:18
-      }
-      scope 3 {
-          debug v => _9;                   // in scope 3 at $DIR/separate_const_switch.rs:+11:31: +11:32
-      }
-      scope 4 {
-          debug r => _11;                  // in scope 4 at $DIR/separate_const_switch.rs:+12:28: +12:29
-      }
-  
-      bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-          _3 = discriminant(_1);           // scope 0 at $DIR/separate_const_switch.rs:+6:15: +6:16
-          switchInt(move _3) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/separate_const_switch.rs:+6:9: +6:16
-      }
-  
-      bb1: {
-          StorageLive(_6);                 // scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
-          _6 = ((_1 as Err).0: usize);     // scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
-          StorageLive(_7);                 // scope 2 at $DIR/separate_const_switch.rs:+8:42: +8:43
-          _7 = _6;                         // scope 2 at $DIR/separate_const_switch.rs:+8:42: +8:43
-          Deinit(_2);                      // scope 2 at $DIR/separate_const_switch.rs:+8:23: +8:44
-          ((_2 as Break).0: usize) = move _7; // scope 2 at $DIR/separate_const_switch.rs:+8:23: +8:44
-          discriminant(_2) = 1;            // scope 2 at $DIR/separate_const_switch.rs:+8:23: +8:44
-          StorageDead(_7);                 // scope 2 at $DIR/separate_const_switch.rs:+8:43: +8:44
-          StorageDead(_6);                 // scope 0 at $DIR/separate_const_switch.rs:+8:43: +8:44
--         _8 = discriminant(_2);           // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
--         switchInt(move _8) -> [0_isize: bb6, 1_isize: bb4, otherwise: bb5]; // scope 0 at $DIR/separate_const_switch.rs:+5:5: +10:6
-+         _8 = const 1_isize;              // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-+         switchInt(const 1_isize) -> [0_isize: bb6, 1_isize: bb4, otherwise: bb5]; // scope 0 at $DIR/separate_const_switch.rs:+5:5: +10:6
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/separate_const_switch.rs:+6:15: +6:16
-      }
-  
-      bb3: {
-          StorageLive(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
-          _4 = ((_1 as Ok).0: i32);        // scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
-          StorageLive(_5);                 // scope 1 at $DIR/separate_const_switch.rs:+7:44: +7:45
-          _5 = _4;                         // scope 1 at $DIR/separate_const_switch.rs:+7:44: +7:45
-          Deinit(_2);                      // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
-          ((_2 as Continue).0: i32) = move _5; // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
-          discriminant(_2) = 0;            // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
-          StorageDead(_5);                 // scope 1 at $DIR/separate_const_switch.rs:+7:45: +7:46
-          StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+7:45: +7:46
--         _8 = discriminant(_2);           // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
--         switchInt(move _8) -> [0_isize: bb6, 1_isize: bb4, otherwise: bb5]; // scope 0 at $DIR/separate_const_switch.rs:+5:5: +10:6
-+         _8 = const 0_isize;              // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-+         switchInt(const 0_isize) -> [0_isize: bb6, 1_isize: bb4, otherwise: bb5]; // scope 0 at $DIR/separate_const_switch.rs:+5:5: +10:6
-      }
-  
-      bb4: {
-          StorageLive(_11);                // scope 0 at $DIR/separate_const_switch.rs:+12:28: +12:29
-          _11 = ((_2 as Break).0: usize);  // scope 0 at $DIR/separate_const_switch.rs:+12:28: +12:29
-          Deinit(_0);                      // scope 4 at $DIR/separate_const_switch.rs:+12:34: +12:38
-          discriminant(_0) = 0;            // scope 4 at $DIR/separate_const_switch.rs:+12:34: +12:38
-          StorageDead(_11);                // scope 0 at $DIR/separate_const_switch.rs:+12:37: +12:38
-          goto -> bb7;                     // scope 0 at $DIR/separate_const_switch.rs:+12:37: +12:38
-      }
-  
-      bb5: {
-          unreachable;                     // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-      }
-  
-      bb6: {
-          StorageLive(_9);                 // scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
-          _9 = ((_2 as Continue).0: i32);  // scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
-          StorageLive(_10);                // scope 3 at $DIR/separate_const_switch.rs:+11:42: +11:43
-          _10 = _9;                        // scope 3 at $DIR/separate_const_switch.rs:+11:42: +11:43
-          Deinit(_0);                      // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
-          ((_0 as Some).0: i32) = move _10; // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
-          discriminant(_0) = 1;            // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
-          StorageDead(_10);                // scope 3 at $DIR/separate_const_switch.rs:+11:43: +11:44
-          StorageDead(_9);                 // scope 0 at $DIR/separate_const_switch.rs:+11:43: +11:44
-          goto -> bb7;                     // scope 0 at $DIR/separate_const_switch.rs:+11:43: +11:44
-      }
-  
-      bb7: {
-          StorageDead(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+14:1: +14:2
-          return;                          // scope 0 at $DIR/separate_const_switch.rs:+14:2: +14:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/separate_const_switch.too_complex.PreCodegen.after.mir b/src/test/mir-opt/separate_const_switch.too_complex.PreCodegen.after.mir
deleted file mode 100644
index 0ee070619e79..000000000000
--- a/src/test/mir-opt/separate_const_switch.too_complex.PreCodegen.after.mir
+++ /dev/null
@@ -1,73 +0,0 @@
-// MIR for `too_complex` after PreCodegen
-
-fn too_complex(_1: Result<i32, usize>) -> Option<i32> {
-    debug x => _1;                       // in scope 0 at $DIR/separate_const_switch.rs:+0:16: +0:17
-    let mut _0: std::option::Option<i32>; // return place in scope 0 at $DIR/separate_const_switch.rs:+0:42: +0:53
-    let mut _2: std::ops::ControlFlow<usize, i32>; // in scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-    let mut _3: isize;                   // in scope 0 at $DIR/separate_const_switch.rs:+7:13: +7:18
-    let _4: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
-    let mut _5: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:+7:44: +7:45
-    let _6: usize;                       // in scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
-    let _7: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
-    let mut _8: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:+11:42: +11:43
-    let _9: usize;                       // in scope 0 at $DIR/separate_const_switch.rs:+12:28: +12:29
-    scope 1 {
-        debug v => _4;                   // in scope 1 at $DIR/separate_const_switch.rs:+7:16: +7:17
-    }
-    scope 2 {
-        debug r => _6;                   // in scope 2 at $DIR/separate_const_switch.rs:+8:17: +8:18
-    }
-    scope 3 {
-        debug v => _7;                   // in scope 3 at $DIR/separate_const_switch.rs:+11:31: +11:32
-    }
-    scope 4 {
-        debug r => _9;                   // in scope 4 at $DIR/separate_const_switch.rs:+12:28: +12:29
-    }
-
-    bb0: {
-        StorageLive(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+5:11: +10:6
-        _3 = discriminant(_1);           // scope 0 at $DIR/separate_const_switch.rs:+6:15: +6:16
-        switchInt(move _3) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/separate_const_switch.rs:+6:9: +6:16
-    }
-
-    bb1: {
-        StorageLive(_6);                 // scope 0 at $DIR/separate_const_switch.rs:+8:17: +8:18
-        StorageDead(_6);                 // scope 0 at $DIR/separate_const_switch.rs:+8:43: +8:44
-        StorageLive(_9);                 // scope 0 at $DIR/separate_const_switch.rs:+12:28: +12:29
-        Deinit(_0);                      // scope 4 at $DIR/separate_const_switch.rs:+12:34: +12:38
-        discriminant(_0) = 0;            // scope 4 at $DIR/separate_const_switch.rs:+12:34: +12:38
-        StorageDead(_9);                 // scope 0 at $DIR/separate_const_switch.rs:+12:37: +12:38
-        goto -> bb4;                     // scope 0 at $DIR/separate_const_switch.rs:+12:37: +12:38
-    }
-
-    bb2: {
-        unreachable;                     // scope 0 at $DIR/separate_const_switch.rs:+6:15: +6:16
-    }
-
-    bb3: {
-        StorageLive(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
-        _4 = ((_1 as Ok).0: i32);        // scope 0 at $DIR/separate_const_switch.rs:+7:16: +7:17
-        StorageLive(_5);                 // scope 1 at $DIR/separate_const_switch.rs:+7:44: +7:45
-        _5 = _4;                         // scope 1 at $DIR/separate_const_switch.rs:+7:44: +7:45
-        Deinit(_2);                      // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
-        ((_2 as Continue).0: i32) = move _5; // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
-        discriminant(_2) = 0;            // scope 1 at $DIR/separate_const_switch.rs:+7:22: +7:46
-        StorageDead(_5);                 // scope 1 at $DIR/separate_const_switch.rs:+7:45: +7:46
-        StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:+7:45: +7:46
-        StorageLive(_7);                 // scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
-        _7 = ((_2 as Continue).0: i32);  // scope 0 at $DIR/separate_const_switch.rs:+11:31: +11:32
-        StorageLive(_8);                 // scope 3 at $DIR/separate_const_switch.rs:+11:42: +11:43
-        _8 = _7;                         // scope 3 at $DIR/separate_const_switch.rs:+11:42: +11:43
-        Deinit(_0);                      // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
-        ((_0 as Some).0: i32) = move _8; // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
-        discriminant(_0) = 1;            // scope 3 at $DIR/separate_const_switch.rs:+11:37: +11:44
-        StorageDead(_8);                 // scope 3 at $DIR/separate_const_switch.rs:+11:43: +11:44
-        StorageDead(_7);                 // scope 0 at $DIR/separate_const_switch.rs:+11:43: +11:44
-        goto -> bb4;                     // scope 0 at $DIR/separate_const_switch.rs:+11:43: +11:44
-    }
-
-    bb4: {
-        StorageDead(_2);                 // scope 0 at $DIR/separate_const_switch.rs:+14:1: +14:2
-        return;                          // scope 0 at $DIR/separate_const_switch.rs:+14:2: +14:2
-    }
-}
diff --git a/src/test/mir-opt/simple-match.rs b/src/test/mir-opt/simple-match.rs
index 44adc55b6f7f..103033c4e2b8 100644
--- a/src/test/mir-opt/simple-match.rs
+++ b/src/test/mir-opt/simple-match.rs
@@ -1,6 +1,6 @@
 // Test that we don't generate unnecessarily large MIR for very simple matches
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR simple_match.match_bool.mir_map.0.mir
 fn match_bool(x: bool) -> usize {
     match x {
diff --git a/src/test/mir-opt/simple_match.match_bool.mir_map.0.64bit.mir b/src/test/mir-opt/simple_match.match_bool.mir_map.0.64bit.mir
deleted file mode 100644
index 3bef6aa0579a..000000000000
--- a/src/test/mir-opt/simple_match.match_bool.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,29 +0,0 @@
-// MIR for `match_bool` 0 mir_map
-
-fn match_bool(_1: bool) -> usize {
-    debug x => _1;                       // in scope 0 at $DIR/simple-match.rs:+0:15: +0:16
-    let mut _0: usize;                   // return place in scope 0 at $DIR/simple-match.rs:+0:27: +0:32
-
-    bb0: {
-        FakeRead(ForMatchedPlace(None), _1); // scope 0 at $DIR/simple-match.rs:+1:11: +1:12
-        switchInt(_1) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/simple-match.rs:+1:5: +1:12
-    }
-
-    bb1: {
-        falseEdge -> [real: bb3, imaginary: bb2]; // scope 0 at $DIR/simple-match.rs:+2:9: +2:13
-    }
-
-    bb2: {
-        _0 = const 20_usize;             // scope 0 at $DIR/simple-match.rs:+3:14: +3:16
-        goto -> bb4;                     // scope 0 at $DIR/simple-match.rs:+3:14: +3:16
-    }
-
-    bb3: {
-        _0 = const 10_usize;             // scope 0 at $DIR/simple-match.rs:+2:17: +2:19
-        goto -> bb4;                     // scope 0 at $DIR/simple-match.rs:+2:17: +2:19
-    }
-
-    bb4: {
-        return;                          // scope 0 at $DIR/simple-match.rs:+5:2: +5:2
-    }
-}
diff --git a/src/test/mir-opt/simple_match.match_bool.mir_map.0.32bit.mir b/src/test/mir-opt/simple_match.match_bool.mir_map.0.mir
similarity index 100%
rename from src/test/mir-opt/simple_match.match_bool.mir_map.0.32bit.mir
rename to src/test/mir-opt/simple_match.match_bool.mir_map.0.mir
diff --git a/src/test/mir-opt/simplify-arm-identity.rs b/src/test/mir-opt/simplify-arm-identity.rs
index bedc86bbacb8..cf6ff57aa96d 100644
--- a/src/test/mir-opt/simplify-arm-identity.rs
+++ b/src/test/mir-opt/simplify-arm-identity.rs
@@ -4,6 +4,9 @@
 // compile-flags: -Zmir-opt-level=3
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
 
+// This pass is broken since deaggregation changed
+// ignore-test
+
 enum Src {
     Foo(u8),
     Bar,
diff --git a/src/test/mir-opt/simplify-arm.rs b/src/test/mir-opt/simplify-arm.rs
index f7dcaa13449e..c247872e2af4 100644
--- a/src/test/mir-opt/simplify-arm.rs
+++ b/src/test/mir-opt/simplify-arm.rs
@@ -6,6 +6,9 @@
 // EMIT_MIR simplify_arm.id_try.SimplifyArmIdentity.diff
 // EMIT_MIR simplify_arm.id_try.SimplifyBranchSame.diff
 
+// This pass is broken since deaggregation changed
+// ignore-test
+
 fn id(o: Option<u8>) -> Option<u8> {
     match o {
         Some(v) => Some(v),
diff --git a/src/test/mir-opt/simplify-locals-removes-unused-discriminant-reads.rs b/src/test/mir-opt/simplify-locals-removes-unused-discriminant-reads.rs
index 84f57deccf7e..d09bd92c4e81 100644
--- a/src/test/mir-opt/simplify-locals-removes-unused-discriminant-reads.rs
+++ b/src/test/mir-opt/simplify-locals-removes-unused-discriminant-reads.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Zunsound-mir-opts
+// unit-test: SimplifyLocals
 
 fn map(x: Option<Box<()>>) -> Option<Box<()>> {
     match x {
@@ -11,5 +11,4 @@ fn main() {
     map(None);
 }
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
 // EMIT_MIR simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.diff
diff --git a/src/test/mir-opt/simplify_arm.id.SimplifyArmIdentity.diff b/src/test/mir-opt/simplify_arm.id.SimplifyArmIdentity.diff
deleted file mode 100644
index 9c3ad4b4df91..000000000000
--- a/src/test/mir-opt/simplify_arm.id.SimplifyArmIdentity.diff
+++ /dev/null
@@ -1,46 +0,0 @@
-- // MIR for `id` before SimplifyArmIdentity
-+ // MIR for `id` after SimplifyArmIdentity
-  
-  fn id(_1: Option<u8>) -> Option<u8> {
-      debug o => _1;                       // in scope 0 at $DIR/simplify-arm.rs:+0:7: +0:8
-      let mut _0: std::option::Option<u8>; // return place in scope 0 at $DIR/simplify-arm.rs:+0:25: +0:35
-      let mut _2: isize;                   // in scope 0 at $DIR/simplify-arm.rs:+2:9: +2:16
-      let _3: u8;                          // in scope 0 at $DIR/simplify-arm.rs:+2:14: +2:15
-      let mut _4: u8;                      // in scope 0 at $DIR/simplify-arm.rs:+2:25: +2:26
-      scope 1 {
-          debug v => _3;                   // in scope 1 at $DIR/simplify-arm.rs:+2:14: +2:15
-      }
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb1, 1_isize: bb3, otherwise: bb2]; // scope 0 at $DIR/simplify-arm.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          Deinit(_0);                      // scope 0 at $DIR/simplify-arm.rs:+3:17: +3:21
-          discriminant(_0) = 0;            // scope 0 at $DIR/simplify-arm.rs:+3:17: +3:21
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+3:17: +3:21
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          StorageLive(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:14: +2:15
-          _3 = ((_1 as Some).0: u8);       // scope 0 at $DIR/simplify-arm.rs:+2:14: +2:15
-          StorageLive(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:25: +2:26
-          _4 = _3;                         // scope 1 at $DIR/simplify-arm.rs:+2:25: +2:26
-          Deinit(_0);                      // scope 1 at $DIR/simplify-arm.rs:+2:20: +2:27
-          ((_0 as Some).0: u8) = move _4;  // scope 1 at $DIR/simplify-arm.rs:+2:20: +2:27
-          discriminant(_0) = 1;            // scope 1 at $DIR/simplify-arm.rs:+2:20: +2:27
-          StorageDead(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:26: +2:27
-          StorageDead(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:26: +2:27
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+2:26: +2:27
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/simplify-arm.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_arm.id.SimplifyBranchSame.diff b/src/test/mir-opt/simplify_arm.id.SimplifyBranchSame.diff
deleted file mode 100644
index 7b3a69936577..000000000000
--- a/src/test/mir-opt/simplify_arm.id.SimplifyBranchSame.diff
+++ /dev/null
@@ -1,46 +0,0 @@
-- // MIR for `id` before SimplifyBranchSame
-+ // MIR for `id` after SimplifyBranchSame
-  
-  fn id(_1: Option<u8>) -> Option<u8> {
-      debug o => _1;                       // in scope 0 at $DIR/simplify-arm.rs:+0:7: +0:8
-      let mut _0: std::option::Option<u8>; // return place in scope 0 at $DIR/simplify-arm.rs:+0:25: +0:35
-      let mut _2: isize;                   // in scope 0 at $DIR/simplify-arm.rs:+2:9: +2:16
-      let _3: u8;                          // in scope 0 at $DIR/simplify-arm.rs:+2:14: +2:15
-      let mut _4: u8;                      // in scope 0 at $DIR/simplify-arm.rs:+2:25: +2:26
-      scope 1 {
-          debug v => _3;                   // in scope 1 at $DIR/simplify-arm.rs:+2:14: +2:15
-      }
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb1, 1_isize: bb3, otherwise: bb2]; // scope 0 at $DIR/simplify-arm.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          Deinit(_0);                      // scope 0 at $DIR/simplify-arm.rs:+3:17: +3:21
-          discriminant(_0) = 0;            // scope 0 at $DIR/simplify-arm.rs:+3:17: +3:21
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+3:17: +3:21
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          StorageLive(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:14: +2:15
-          _3 = ((_1 as Some).0: u8);       // scope 0 at $DIR/simplify-arm.rs:+2:14: +2:15
-          StorageLive(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:25: +2:26
-          _4 = _3;                         // scope 1 at $DIR/simplify-arm.rs:+2:25: +2:26
-          Deinit(_0);                      // scope 1 at $DIR/simplify-arm.rs:+2:20: +2:27
-          ((_0 as Some).0: u8) = move _4;  // scope 1 at $DIR/simplify-arm.rs:+2:20: +2:27
-          discriminant(_0) = 1;            // scope 1 at $DIR/simplify-arm.rs:+2:20: +2:27
-          StorageDead(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:26: +2:27
-          StorageDead(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:26: +2:27
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+2:26: +2:27
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/simplify-arm.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_arm.id_result.SimplifyArmIdentity.diff b/src/test/mir-opt/simplify_arm.id_result.SimplifyArmIdentity.diff
deleted file mode 100644
index 31d8453cec01..000000000000
--- a/src/test/mir-opt/simplify_arm.id_result.SimplifyArmIdentity.diff
+++ /dev/null
@@ -1,58 +0,0 @@
-- // MIR for `id_result` before SimplifyArmIdentity
-+ // MIR for `id_result` after SimplifyArmIdentity
-  
-  fn id_result(_1: Result<u8, i32>) -> Result<u8, i32> {
-      debug r => _1;                       // in scope 0 at $DIR/simplify-arm.rs:+0:14: +0:15
-      let mut _0: std::result::Result<u8, i32>; // return place in scope 0 at $DIR/simplify-arm.rs:+0:37: +0:52
-      let mut _2: isize;                   // in scope 0 at $DIR/simplify-arm.rs:+2:9: +2:14
-      let _3: u8;                          // in scope 0 at $DIR/simplify-arm.rs:+2:12: +2:13
-      let mut _4: u8;                      // in scope 0 at $DIR/simplify-arm.rs:+2:21: +2:22
-      let _5: i32;                         // in scope 0 at $DIR/simplify-arm.rs:+3:13: +3:14
-      let mut _6: i32;                     // in scope 0 at $DIR/simplify-arm.rs:+3:23: +3:24
-      scope 1 {
-          debug x => _3;                   // in scope 1 at $DIR/simplify-arm.rs:+2:12: +2:13
-      }
-      scope 2 {
-          debug y => _5;                   // in scope 2 at $DIR/simplify-arm.rs:+3:13: +3:14
-      }
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify-arm.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          StorageLive(_5);                 // scope 0 at $DIR/simplify-arm.rs:+3:13: +3:14
-          _5 = ((_1 as Err).0: i32);       // scope 0 at $DIR/simplify-arm.rs:+3:13: +3:14
-          StorageLive(_6);                 // scope 2 at $DIR/simplify-arm.rs:+3:23: +3:24
-          _6 = _5;                         // scope 2 at $DIR/simplify-arm.rs:+3:23: +3:24
-          Deinit(_0);                      // scope 2 at $DIR/simplify-arm.rs:+3:19: +3:25
-          ((_0 as Err).0: i32) = move _6;  // scope 2 at $DIR/simplify-arm.rs:+3:19: +3:25
-          discriminant(_0) = 1;            // scope 2 at $DIR/simplify-arm.rs:+3:19: +3:25
-          StorageDead(_6);                 // scope 2 at $DIR/simplify-arm.rs:+3:24: +3:25
-          StorageDead(_5);                 // scope 0 at $DIR/simplify-arm.rs:+3:24: +3:25
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+3:24: +3:25
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          StorageLive(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:12: +2:13
-          _3 = ((_1 as Ok).0: u8);         // scope 0 at $DIR/simplify-arm.rs:+2:12: +2:13
-          StorageLive(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:21: +2:22
-          _4 = _3;                         // scope 1 at $DIR/simplify-arm.rs:+2:21: +2:22
-          Deinit(_0);                      // scope 1 at $DIR/simplify-arm.rs:+2:18: +2:23
-          ((_0 as Ok).0: u8) = move _4;    // scope 1 at $DIR/simplify-arm.rs:+2:18: +2:23
-          discriminant(_0) = 0;            // scope 1 at $DIR/simplify-arm.rs:+2:18: +2:23
-          StorageDead(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:22: +2:23
-          StorageDead(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:22: +2:23
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+2:22: +2:23
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/simplify-arm.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_arm.id_result.SimplifyBranchSame.diff b/src/test/mir-opt/simplify_arm.id_result.SimplifyBranchSame.diff
deleted file mode 100644
index 3692ebf747bd..000000000000
--- a/src/test/mir-opt/simplify_arm.id_result.SimplifyBranchSame.diff
+++ /dev/null
@@ -1,58 +0,0 @@
-- // MIR for `id_result` before SimplifyBranchSame
-+ // MIR for `id_result` after SimplifyBranchSame
-  
-  fn id_result(_1: Result<u8, i32>) -> Result<u8, i32> {
-      debug r => _1;                       // in scope 0 at $DIR/simplify-arm.rs:+0:14: +0:15
-      let mut _0: std::result::Result<u8, i32>; // return place in scope 0 at $DIR/simplify-arm.rs:+0:37: +0:52
-      let mut _2: isize;                   // in scope 0 at $DIR/simplify-arm.rs:+2:9: +2:14
-      let _3: u8;                          // in scope 0 at $DIR/simplify-arm.rs:+2:12: +2:13
-      let mut _4: u8;                      // in scope 0 at $DIR/simplify-arm.rs:+2:21: +2:22
-      let _5: i32;                         // in scope 0 at $DIR/simplify-arm.rs:+3:13: +3:14
-      let mut _6: i32;                     // in scope 0 at $DIR/simplify-arm.rs:+3:23: +3:24
-      scope 1 {
-          debug x => _3;                   // in scope 1 at $DIR/simplify-arm.rs:+2:12: +2:13
-      }
-      scope 2 {
-          debug y => _5;                   // in scope 2 at $DIR/simplify-arm.rs:+3:13: +3:14
-      }
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify-arm.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          StorageLive(_5);                 // scope 0 at $DIR/simplify-arm.rs:+3:13: +3:14
-          _5 = ((_1 as Err).0: i32);       // scope 0 at $DIR/simplify-arm.rs:+3:13: +3:14
-          StorageLive(_6);                 // scope 2 at $DIR/simplify-arm.rs:+3:23: +3:24
-          _6 = _5;                         // scope 2 at $DIR/simplify-arm.rs:+3:23: +3:24
-          Deinit(_0);                      // scope 2 at $DIR/simplify-arm.rs:+3:19: +3:25
-          ((_0 as Err).0: i32) = move _6;  // scope 2 at $DIR/simplify-arm.rs:+3:19: +3:25
-          discriminant(_0) = 1;            // scope 2 at $DIR/simplify-arm.rs:+3:19: +3:25
-          StorageDead(_6);                 // scope 2 at $DIR/simplify-arm.rs:+3:24: +3:25
-          StorageDead(_5);                 // scope 0 at $DIR/simplify-arm.rs:+3:24: +3:25
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+3:24: +3:25
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/simplify-arm.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          StorageLive(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:12: +2:13
-          _3 = ((_1 as Ok).0: u8);         // scope 0 at $DIR/simplify-arm.rs:+2:12: +2:13
-          StorageLive(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:21: +2:22
-          _4 = _3;                         // scope 1 at $DIR/simplify-arm.rs:+2:21: +2:22
-          Deinit(_0);                      // scope 1 at $DIR/simplify-arm.rs:+2:18: +2:23
-          ((_0 as Ok).0: u8) = move _4;    // scope 1 at $DIR/simplify-arm.rs:+2:18: +2:23
-          discriminant(_0) = 0;            // scope 1 at $DIR/simplify-arm.rs:+2:18: +2:23
-          StorageDead(_4);                 // scope 1 at $DIR/simplify-arm.rs:+2:22: +2:23
-          StorageDead(_3);                 // scope 0 at $DIR/simplify-arm.rs:+2:22: +2:23
-          goto -> bb4;                     // scope 0 at $DIR/simplify-arm.rs:+2:22: +2:23
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/simplify-arm.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_arm_identity.main.SimplifyArmIdentity.32bit.diff b/src/test/mir-opt/simplify_arm_identity.main.SimplifyArmIdentity.32bit.diff
deleted file mode 100644
index 118f5dd0abb4..000000000000
--- a/src/test/mir-opt/simplify_arm_identity.main.SimplifyArmIdentity.32bit.diff
+++ /dev/null
@@ -1,61 +0,0 @@
-- // MIR for `main` before SimplifyArmIdentity
-+ // MIR for `main` after SimplifyArmIdentity
-  
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/simplify-arm-identity.rs:+0:11: +0:11
-      let _1: Src;                         // in scope 0 at $DIR/simplify-arm-identity.rs:+1:9: +1:10
-      let mut _2: Dst;                     // in scope 0 at $DIR/simplify-arm-identity.rs:+2:18: +5:6
-      let mut _3: isize;                   // in scope 0 at $DIR/simplify-arm-identity.rs:+3:9: +3:20
-      let mut _5: u8;                      // in scope 0 at $DIR/simplify-arm-identity.rs:+3:33: +3:34
-      scope 1 {
-          debug e => _1;                   // in scope 1 at $DIR/simplify-arm-identity.rs:+1:9: +1:10
-          let _4: u8;                      // in scope 1 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          scope 2 {
-          }
-          scope 3 {
-              debug x => _4;               // in scope 3 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          }
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/simplify-arm-identity.rs:+1:9: +1:10
-          Deinit(_1);                      // scope 0 at $DIR/simplify-arm-identity.rs:+1:18: +1:29
-          ((_1 as Foo).0: u8) = const 0_u8; // scope 0 at $DIR/simplify-arm-identity.rs:+1:18: +1:29
-          discriminant(_1) = 0;            // scope 0 at $DIR/simplify-arm-identity.rs:+1:18: +1:29
-          StorageLive(_2);                 // scope 1 at $DIR/simplify-arm-identity.rs:+2:18: +5:6
-          _3 = const 0_isize;              // scope 1 at $DIR/simplify-arm-identity.rs:+2:24: +2:25
-          goto -> bb3;                     // scope 1 at $DIR/simplify-arm-identity.rs:+2:18: +2:25
-      }
-  
-      bb1: {
-          Deinit(_2);                      // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-          ((_2 as Foo).0: u8) = const 0_u8; // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-          discriminant(_2) = 0;            // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-          goto -> bb4;                     // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-      }
-  
-      bb2: {
-          unreachable;                     // scope 1 at $DIR/simplify-arm-identity.rs:+2:24: +2:25
-      }
-  
-      bb3: {
-          StorageLive(_4);                 // scope 1 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          _4 = ((_1 as Foo).0: u8);        // scope 1 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          StorageLive(_5);                 // scope 3 at $DIR/simplify-arm-identity.rs:+3:33: +3:34
-          _5 = _4;                         // scope 3 at $DIR/simplify-arm-identity.rs:+3:33: +3:34
-          Deinit(_2);                      // scope 3 at $DIR/simplify-arm-identity.rs:+3:24: +3:35
-          ((_2 as Foo).0: u8) = move _5;   // scope 3 at $DIR/simplify-arm-identity.rs:+3:24: +3:35
-          discriminant(_2) = 0;            // scope 3 at $DIR/simplify-arm-identity.rs:+3:24: +3:35
-          StorageDead(_5);                 // scope 3 at $DIR/simplify-arm-identity.rs:+3:34: +3:35
-          StorageDead(_4);                 // scope 1 at $DIR/simplify-arm-identity.rs:+3:34: +3:35
-          goto -> bb4;                     // scope 1 at $DIR/simplify-arm-identity.rs:+3:34: +3:35
-      }
-  
-      bb4: {
-          StorageDead(_2);                 // scope 1 at $DIR/simplify-arm-identity.rs:+5:6: +5:7
-          nop;                             // scope 0 at $DIR/simplify-arm-identity.rs:+0:11: +6:2
-          StorageDead(_1);                 // scope 0 at $DIR/simplify-arm-identity.rs:+6:1: +6:2
-          return;                          // scope 0 at $DIR/simplify-arm-identity.rs:+6:2: +6:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_arm_identity.main.SimplifyArmIdentity.64bit.diff b/src/test/mir-opt/simplify_arm_identity.main.SimplifyArmIdentity.64bit.diff
deleted file mode 100644
index 118f5dd0abb4..000000000000
--- a/src/test/mir-opt/simplify_arm_identity.main.SimplifyArmIdentity.64bit.diff
+++ /dev/null
@@ -1,61 +0,0 @@
-- // MIR for `main` before SimplifyArmIdentity
-+ // MIR for `main` after SimplifyArmIdentity
-  
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/simplify-arm-identity.rs:+0:11: +0:11
-      let _1: Src;                         // in scope 0 at $DIR/simplify-arm-identity.rs:+1:9: +1:10
-      let mut _2: Dst;                     // in scope 0 at $DIR/simplify-arm-identity.rs:+2:18: +5:6
-      let mut _3: isize;                   // in scope 0 at $DIR/simplify-arm-identity.rs:+3:9: +3:20
-      let mut _5: u8;                      // in scope 0 at $DIR/simplify-arm-identity.rs:+3:33: +3:34
-      scope 1 {
-          debug e => _1;                   // in scope 1 at $DIR/simplify-arm-identity.rs:+1:9: +1:10
-          let _4: u8;                      // in scope 1 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          scope 2 {
-          }
-          scope 3 {
-              debug x => _4;               // in scope 3 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          }
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/simplify-arm-identity.rs:+1:9: +1:10
-          Deinit(_1);                      // scope 0 at $DIR/simplify-arm-identity.rs:+1:18: +1:29
-          ((_1 as Foo).0: u8) = const 0_u8; // scope 0 at $DIR/simplify-arm-identity.rs:+1:18: +1:29
-          discriminant(_1) = 0;            // scope 0 at $DIR/simplify-arm-identity.rs:+1:18: +1:29
-          StorageLive(_2);                 // scope 1 at $DIR/simplify-arm-identity.rs:+2:18: +5:6
-          _3 = const 0_isize;              // scope 1 at $DIR/simplify-arm-identity.rs:+2:24: +2:25
-          goto -> bb3;                     // scope 1 at $DIR/simplify-arm-identity.rs:+2:18: +2:25
-      }
-  
-      bb1: {
-          Deinit(_2);                      // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-          ((_2 as Foo).0: u8) = const 0_u8; // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-          discriminant(_2) = 0;            // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-          goto -> bb4;                     // scope 1 at $DIR/simplify-arm-identity.rs:+4:21: +4:32
-      }
-  
-      bb2: {
-          unreachable;                     // scope 1 at $DIR/simplify-arm-identity.rs:+2:24: +2:25
-      }
-  
-      bb3: {
-          StorageLive(_4);                 // scope 1 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          _4 = ((_1 as Foo).0: u8);        // scope 1 at $DIR/simplify-arm-identity.rs:+3:18: +3:19
-          StorageLive(_5);                 // scope 3 at $DIR/simplify-arm-identity.rs:+3:33: +3:34
-          _5 = _4;                         // scope 3 at $DIR/simplify-arm-identity.rs:+3:33: +3:34
-          Deinit(_2);                      // scope 3 at $DIR/simplify-arm-identity.rs:+3:24: +3:35
-          ((_2 as Foo).0: u8) = move _5;   // scope 3 at $DIR/simplify-arm-identity.rs:+3:24: +3:35
-          discriminant(_2) = 0;            // scope 3 at $DIR/simplify-arm-identity.rs:+3:24: +3:35
-          StorageDead(_5);                 // scope 3 at $DIR/simplify-arm-identity.rs:+3:34: +3:35
-          StorageDead(_4);                 // scope 1 at $DIR/simplify-arm-identity.rs:+3:34: +3:35
-          goto -> bb4;                     // scope 1 at $DIR/simplify-arm-identity.rs:+3:34: +3:35
-      }
-  
-      bb4: {
-          StorageDead(_2);                 // scope 1 at $DIR/simplify-arm-identity.rs:+5:6: +5:7
-          nop;                             // scope 0 at $DIR/simplify-arm-identity.rs:+0:11: +6:2
-          StorageDead(_1);                 // scope 0 at $DIR/simplify-arm-identity.rs:+6:1: +6:2
-          return;                          // scope 0 at $DIR/simplify-arm-identity.rs:+6:2: +6:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.64bit.diff b/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.64bit.diff
deleted file mode 100644
index d8e0657c6ebc..000000000000
--- a/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.64bit.diff
+++ /dev/null
@@ -1,43 +0,0 @@
-- // MIR for `map` before SimplifyLocals
-+ // MIR for `map` after SimplifyLocals
-  
-  fn map(_1: Option<Box<()>>) -> Option<Box<()>> {
-      debug x => _1;                       // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+0:8: +0:9
-      let mut _0: std::option::Option<std::boxed::Box<()>>; // return place in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+0:31: +0:46
-      let mut _2: isize;                   // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+2:9: +2:13
--     let _3: std::boxed::Box<()>;         // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
--     let mut _4: std::boxed::Box<()>;     // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:25: +3:26
--     let mut _5: bool;                    // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
--     let mut _6: isize;                   // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
--     let mut _7: isize;                   // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
-      scope 1 {
-          debug x => ((_0 as Some).0: std::boxed::Box<()>); // in scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
-      }
-  
-      bb0: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:11: +1:12
-          switchInt(move _2) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:5: +1:12
-      }
-  
-      bb1: {
-          ((_0 as Some).0: std::boxed::Box<()>) = move ((_1 as Some).0: std::boxed::Box<()>); // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
-          Deinit(_0);                      // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:20: +3:27
-          discriminant(_0) = 1;            // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:20: +3:27
-          goto -> bb4;                     // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:26: +3:27
-      }
-  
-      bb2: {
-          unreachable;                     // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:11: +1:12
-      }
-  
-      bb3: {
-          Deinit(_0);                      // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+2:17: +2:21
-          discriminant(_0) = 0;            // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+2:17: +2:21
-          goto -> bb4;                     // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+2:17: +2:21
-      }
-  
-      bb4: {
-          return;                          // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:2: +5:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.32bit.diff b/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.diff
similarity index 61%
rename from src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.32bit.diff
rename to src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.diff
index d8e0657c6ebc..51d26b08b2a1 100644
--- a/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.32bit.diff
+++ b/src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.diff
@@ -5,24 +5,32 @@
       debug x => _1;                       // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+0:8: +0:9
       let mut _0: std::option::Option<std::boxed::Box<()>>; // return place in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+0:31: +0:46
       let mut _2: isize;                   // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+2:9: +2:13
--     let _3: std::boxed::Box<()>;         // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
--     let mut _4: std::boxed::Box<()>;     // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:25: +3:26
+      let _3: std::boxed::Box<()>;         // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
+      let mut _4: std::boxed::Box<()>;     // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:25: +3:26
 -     let mut _5: bool;                    // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
 -     let mut _6: isize;                   // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
 -     let mut _7: isize;                   // in scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
       scope 1 {
-          debug x => ((_0 as Some).0: std::boxed::Box<()>); // in scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
+          debug x => _3;                   // in scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
       }
   
       bb0: {
+-         _5 = const false;                // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:11: +1:12
+-         _5 = const true;                 // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:11: +1:12
           _2 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:11: +1:12
           switchInt(move _2) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+1:5: +1:12
       }
   
       bb1: {
-          ((_0 as Some).0: std::boxed::Box<()>) = move ((_1 as Some).0: std::boxed::Box<()>); // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
+          StorageLive(_3);                 // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
+          _3 = move ((_1 as Some).0: std::boxed::Box<()>); // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:14: +3:15
+          StorageLive(_4);                 // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:25: +3:26
+          _4 = move _3;                    // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:25: +3:26
           Deinit(_0);                      // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:20: +3:27
+          ((_0 as Some).0: std::boxed::Box<()>) = move _4; // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:20: +3:27
           discriminant(_0) = 1;            // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:20: +3:27
+          StorageDead(_4);                 // scope 1 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:26: +3:27
+          StorageDead(_3);                 // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:26: +3:27
           goto -> bb4;                     // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+3:26: +3:27
       }
   
@@ -37,6 +45,7 @@
       }
   
       bb4: {
+-         _6 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:1: +5:2
           return;                          // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:+5:2: +5:2
       }
   }
diff --git a/src/test/mir-opt/simplify_try.rs b/src/test/mir-opt/simplify_try.rs
deleted file mode 100644
index 15e351e7d501..000000000000
--- a/src/test/mir-opt/simplify_try.rs
+++ /dev/null
@@ -1,30 +0,0 @@
-// compile-flags: -Zunsound-mir-opts
-// EMIT_MIR simplify_try.try_identity.SimplifyArmIdentity.diff
-// EMIT_MIR simplify_try.try_identity.SimplifyBranchSame.after.mir
-// EMIT_MIR simplify_try.try_identity.SimplifyLocals.after.mir
-// EMIT_MIR simplify_try.try_identity.DestinationPropagation.diff
-
-
-fn into_result<T, E>(r: Result<T, E>) -> Result<T, E> {
-    r
-}
-
-fn from_error<T, E>(e: E) -> Result<T, E> {
-    Err(e)
-}
-
-// This was written to the `?` from `try_trait`, but `try_trait_v2` uses a different structure,
-// so the relevant desugar is copied inline in order to keep the test testing the same thing.
-// FIXME(#85133): while this might be useful for `r#try!`, it would be nice to have a MIR
-// optimization that picks up the `?` desugaring, as `SimplifyArmIdentity` does not.
-fn try_identity(x: Result<u32, i32>) -> Result<u32, i32> {
-    let y = match into_result(x) {
-        Err(e) => return from_error(From::from(e)),
-        Ok(v) => v,
-    };
-    Ok(y)
-}
-
-fn main() {
-    let _ = try_identity(Ok(0));
-}
diff --git a/src/test/mir-opt/slice-drop-shim.rs b/src/test/mir-opt/slice-drop-shim.rs
index 0fd32906db6b..344c1af2c913 100644
--- a/src/test/mir-opt/slice-drop-shim.rs
+++ b/src/test/mir-opt/slice-drop-shim.rs
@@ -1,6 +1,6 @@
 // compile-flags: -Zmir-opt-level=0
 
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 // EMIT_MIR core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.mir
 fn main() {
     let _fn = std::ptr::drop_in_place::<[String]> as unsafe fn(_);
diff --git a/src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.64bit.mir b/src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.64bit.mir
deleted file mode 100644
index b4b317e84afb..000000000000
--- a/src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.64bit.mir
+++ /dev/null
@@ -1,101 +0,0 @@
-// MIR for `std::ptr::drop_in_place` before AddMovesForPackedDrops
-
-fn std::ptr::drop_in_place(_1: *mut [String]) -> () {
-    let mut _0: ();                      // return place in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _2: usize;                   // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _3: usize;                   // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _4: usize;                   // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _5: *mut std::string::String; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _6: bool;                    // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _7: *mut std::string::String; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _8: bool;                    // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _9: *mut std::string::String; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _10: *mut std::string::String; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _11: *mut std::string::String; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _12: bool;                   // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _13: *mut std::string::String; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _14: bool;                   // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _15: *mut [std::string::String]; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-
-    bb0: {
-        goto -> bb15;                    // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb1: {
-        return;                          // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb2 (cleanup): {
-        resume;                          // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb3 (cleanup): {
-        _5 = &raw mut (*_1)[_4];         // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _4 = Add(move _4, const 1_usize); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        drop((*_5)) -> bb4;              // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb4 (cleanup): {
-        _6 = Eq(_4, _3);                 // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        switchInt(move _6) -> [false: bb3, otherwise: bb2]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb5: {
-        _7 = &raw mut (*_1)[_4];         // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _4 = Add(move _4, const 1_usize); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        drop((*_7)) -> [return: bb6, unwind: bb4]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb6: {
-        _8 = Eq(_4, _3);                 // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        switchInt(move _8) -> [false: bb5, otherwise: bb1]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb7: {
-        _4 = const 0_usize;              // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        goto -> bb6;                     // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb8: {
-        goto -> bb7;                     // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb9 (cleanup): {
-        _11 = _9;                        // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _9 = Offset(move _9, const 1_usize); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        drop((*_11)) -> bb10;            // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb10 (cleanup): {
-        _12 = Eq(_9, _10);               // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        switchInt(move _12) -> [false: bb9, otherwise: bb2]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb11: {
-        _13 = _9;                        // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _9 = Offset(move _9, const 1_usize); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        drop((*_13)) -> [return: bb12, unwind: bb10]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb12: {
-        _14 = Eq(_9, _10);               // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        switchInt(move _14) -> [false: bb11, otherwise: bb1]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb13: {
-        _15 = &raw mut (*_1);            // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _9 = move _15 as *mut std::string::String (Misc); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _10 = Offset(_9, move _3);       // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        goto -> bb12;                    // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb14: {
-        goto -> bb13;                    // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb15: {
-        _2 = SizeOf(std::string::String); // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _3 = Len((*_1));                 // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        switchInt(move _2) -> [0_usize: bb8, otherwise: bb14]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-}
diff --git a/src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.32bit.mir b/src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.mir
similarity index 100%
rename from src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.32bit.mir
rename to src/test/mir-opt/slice_drop_shim.core.ptr-drop_in_place.[String].AddMovesForPackedDrops.before.mir
diff --git a/src/test/mir-opt/storage_live_dead_in_statics.XXX.mir_map.0.mir b/src/test/mir-opt/storage_live_dead_in_statics.XXX.mir_map.0.mir
index 4127a0c9555e..e50067ea25ef 100644
--- a/src/test/mir-opt/storage_live_dead_in_statics.XXX.mir_map.0.mir
+++ b/src/test/mir-opt/storage_live_dead_in_statics.XXX.mir_map.0.mir
@@ -198,6 +198,6 @@ static XXX: &Foo = {
         _0 = &(*_1);                     // scope 0 at $DIR/storage_live_dead_in_statics.rs:+0:28: +18:2
         StorageDead(_5);                 // scope 0 at $DIR/storage_live_dead_in_statics.rs:+18:1: +18:2
         StorageDead(_1);                 // scope 0 at $DIR/storage_live_dead_in_statics.rs:+18:1: +18:2
-        return;                          // scope 0 at $DIR/storage_live_dead_in_statics.rs:+0:1: +18:2
+        return;                          // scope 0 at $DIR/storage_live_dead_in_statics.rs:+0:1: +18:3
     }
 }
diff --git a/src/test/mir-opt/storage_ranges.main.nll.0.mir b/src/test/mir-opt/storage_ranges.main.nll.0.mir
index 812eb3b82a6d..8e10e70f192d 100644
--- a/src/test/mir-opt/storage_ranges.main.nll.0.mir
+++ b/src/test/mir-opt/storage_ranges.main.nll.0.mir
@@ -7,16 +7,15 @@
 | Inferred Region Values
 | '_#0r | U0 | {bb0[0..=22], '_#0r, '_#1r}
 | '_#1r | U0 | {bb0[0..=22], '_#1r}
-| '_#2r | U0 | {}
-| '_#3r | U0 | {bb0[10..=11]}
-| '_#4r | U0 | {bb0[11]}
+| '_#2r | U0 | {bb0[10..=11]}
+| '_#3r | U0 | {bb0[11]}
 |
 | Inference Constraints
 | '_#0r live at {bb0[0..=22]}
 | '_#1r live at {bb0[0..=22]}
-| '_#3r live at {bb0[10]}
-| '_#4r live at {bb0[11]}
-| '_#3r: '_#4r due to Assignment at Single(bb0[10]) ($DIR/storage_ranges.rs:6:17: 6:25 (#0)
+| '_#2r live at {bb0[10]}
+| '_#3r live at {bb0[11]}
+| '_#2r: '_#3r due to Assignment at Single(bb0[10]) ($DIR/storage_ranges.rs:6:17: 6:25 (#0)
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/storage_ranges.rs:+0:11: +0:11
diff --git a/src/test/mir-opt/try_identity_e2e.new.PreCodegen.after.mir b/src/test/mir-opt/try_identity_e2e.new.PreCodegen.after.mir
new file mode 100644
index 000000000000..330929c58c91
--- /dev/null
+++ b/src/test/mir-opt/try_identity_e2e.new.PreCodegen.after.mir
@@ -0,0 +1,96 @@
+// MIR for `new` after PreCodegen
+
+fn new(_1: Result<T, E>) -> Result<T, E> {
+    debug x => _1;                       // in scope 0 at $DIR/try_identity_e2e.rs:+0:14: +0:15
+    let mut _0: std::result::Result<T, E>; // return place in scope 0 at $DIR/try_identity_e2e.rs:+0:34: +0:46
+    let mut _2: T;                       // in scope 0 at $DIR/try_identity_e2e.rs:+2:9: +10:10
+    let mut _3: std::ops::ControlFlow<E, T>; // in scope 0 at $DIR/try_identity_e2e.rs:+2:15: +7:10
+    let mut _4: isize;                   // in scope 0 at $DIR/try_identity_e2e.rs:+4:17: +4:22
+    let _5: T;                           // in scope 0 at $DIR/try_identity_e2e.rs:+4:20: +4:21
+    let mut _6: T;                       // in scope 0 at $DIR/try_identity_e2e.rs:+4:48: +4:49
+    let _7: E;                           // in scope 0 at $DIR/try_identity_e2e.rs:+5:21: +5:22
+    let mut _8: E;                       // in scope 0 at $DIR/try_identity_e2e.rs:+5:46: +5:47
+    let mut _9: isize;                   // in scope 0 at $DIR/try_identity_e2e.rs:+8:13: +8:37
+    let _10: T;                          // in scope 0 at $DIR/try_identity_e2e.rs:+8:35: +8:36
+    let _11: E;                          // in scope 0 at $DIR/try_identity_e2e.rs:+9:32: +9:33
+    let mut _12: E;                      // in scope 0 at $DIR/try_identity_e2e.rs:+9:49: +9:50
+    scope 1 {
+        debug v => _5;                   // in scope 1 at $DIR/try_identity_e2e.rs:+4:20: +4:21
+    }
+    scope 2 {
+        debug e => _7;                   // in scope 2 at $DIR/try_identity_e2e.rs:+5:21: +5:22
+    }
+    scope 3 {
+        debug v => _10;                  // in scope 3 at $DIR/try_identity_e2e.rs:+8:35: +8:36
+    }
+    scope 4 {
+        debug e => _11;                  // in scope 4 at $DIR/try_identity_e2e.rs:+9:32: +9:33
+    }
+
+    bb0: {
+        StorageLive(_2);                 // scope 0 at $DIR/try_identity_e2e.rs:+2:9: +10:10
+        StorageLive(_3);                 // scope 0 at $DIR/try_identity_e2e.rs:+2:15: +7:10
+        _4 = discriminant(_1);           // scope 0 at $DIR/try_identity_e2e.rs:+3:19: +3:20
+        switchInt(move _4) -> [0_isize: bb2, 1_isize: bb1, otherwise: bb4]; // scope 0 at $DIR/try_identity_e2e.rs:+3:13: +3:20
+    }
+
+    bb1: {
+        StorageLive(_7);                 // scope 0 at $DIR/try_identity_e2e.rs:+5:21: +5:22
+        _7 = move ((_1 as Err).0: E);    // scope 0 at $DIR/try_identity_e2e.rs:+5:21: +5:22
+        StorageLive(_8);                 // scope 2 at $DIR/try_identity_e2e.rs:+5:46: +5:47
+        _8 = move _7;                    // scope 2 at $DIR/try_identity_e2e.rs:+5:46: +5:47
+        Deinit(_3);                      // scope 2 at $DIR/try_identity_e2e.rs:+5:27: +5:48
+        ((_3 as Break).0: E) = move _8;  // scope 2 at $DIR/try_identity_e2e.rs:+5:27: +5:48
+        discriminant(_3) = 1;            // scope 2 at $DIR/try_identity_e2e.rs:+5:27: +5:48
+        StorageDead(_8);                 // scope 2 at $DIR/try_identity_e2e.rs:+5:47: +5:48
+        StorageDead(_7);                 // scope 0 at $DIR/try_identity_e2e.rs:+5:47: +5:48
+        _9 = discriminant(_3);           // scope 0 at $DIR/try_identity_e2e.rs:+2:15: +7:10
+        switchInt(move _9) -> [0_isize: bb5, 1_isize: bb3, otherwise: bb4]; // scope 0 at $DIR/try_identity_e2e.rs:+2:9: +7:10
+    }
+
+    bb2: {
+        StorageLive(_5);                 // scope 0 at $DIR/try_identity_e2e.rs:+4:20: +4:21
+        _5 = move ((_1 as Ok).0: T);     // scope 0 at $DIR/try_identity_e2e.rs:+4:20: +4:21
+        StorageLive(_6);                 // scope 1 at $DIR/try_identity_e2e.rs:+4:48: +4:49
+        _6 = move _5;                    // scope 1 at $DIR/try_identity_e2e.rs:+4:48: +4:49
+        Deinit(_3);                      // scope 1 at $DIR/try_identity_e2e.rs:+4:26: +4:50
+        ((_3 as Continue).0: T) = move _6; // scope 1 at $DIR/try_identity_e2e.rs:+4:26: +4:50
+        discriminant(_3) = 0;            // scope 1 at $DIR/try_identity_e2e.rs:+4:26: +4:50
+        StorageDead(_6);                 // scope 1 at $DIR/try_identity_e2e.rs:+4:49: +4:50
+        StorageDead(_5);                 // scope 0 at $DIR/try_identity_e2e.rs:+4:49: +4:50
+        _9 = discriminant(_3);           // scope 0 at $DIR/try_identity_e2e.rs:+2:15: +7:10
+        switchInt(move _9) -> [0_isize: bb5, 1_isize: bb3, otherwise: bb4]; // scope 0 at $DIR/try_identity_e2e.rs:+2:9: +7:10
+    }
+
+    bb3: {
+        StorageLive(_11);                // scope 0 at $DIR/try_identity_e2e.rs:+9:32: +9:33
+        _11 = move ((_3 as Break).0: E); // scope 0 at $DIR/try_identity_e2e.rs:+9:32: +9:33
+        StorageLive(_12);                // scope 4 at $DIR/try_identity_e2e.rs:+9:49: +9:50
+        _12 = move _11;                  // scope 4 at $DIR/try_identity_e2e.rs:+9:49: +9:50
+        Deinit(_0);                      // scope 4 at $DIR/try_identity_e2e.rs:+9:45: +9:51
+        ((_0 as Err).0: E) = move _12;   // scope 4 at $DIR/try_identity_e2e.rs:+9:45: +9:51
+        discriminant(_0) = 1;            // scope 4 at $DIR/try_identity_e2e.rs:+9:45: +9:51
+        StorageDead(_12);                // scope 4 at $DIR/try_identity_e2e.rs:+9:50: +9:51
+        StorageDead(_11);                // scope 0 at $DIR/try_identity_e2e.rs:+9:50: +9:51
+        StorageDead(_2);                 // scope 0 at $DIR/try_identity_e2e.rs:+11:5: +11:6
+        StorageDead(_3);                 // scope 0 at $DIR/try_identity_e2e.rs:+12:1: +12:2
+        return;                          // scope 0 at $DIR/try_identity_e2e.rs:+12:1: +12:2
+    }
+
+    bb4: {
+        unreachable;                     // scope 0 at $DIR/try_identity_e2e.rs:+2:15: +7:10
+    }
+
+    bb5: {
+        StorageLive(_10);                // scope 0 at $DIR/try_identity_e2e.rs:+8:35: +8:36
+        _10 = move ((_3 as Continue).0: T); // scope 0 at $DIR/try_identity_e2e.rs:+8:35: +8:36
+        _2 = move _10;                   // scope 3 at $DIR/try_identity_e2e.rs:+8:41: +8:42
+        StorageDead(_10);                // scope 0 at $DIR/try_identity_e2e.rs:+8:41: +8:42
+        Deinit(_0);                      // scope 0 at $DIR/try_identity_e2e.rs:+1:5: +11:6
+        ((_0 as Ok).0: T) = move _2;     // scope 0 at $DIR/try_identity_e2e.rs:+1:5: +11:6
+        discriminant(_0) = 0;            // scope 0 at $DIR/try_identity_e2e.rs:+1:5: +11:6
+        StorageDead(_2);                 // scope 0 at $DIR/try_identity_e2e.rs:+11:5: +11:6
+        StorageDead(_3);                 // scope 0 at $DIR/try_identity_e2e.rs:+12:1: +12:2
+        return;                          // scope 0 at $DIR/try_identity_e2e.rs:+12:1: +12:2
+    }
+}
diff --git a/src/test/mir-opt/try_identity_e2e.old.PreCodegen.after.mir b/src/test/mir-opt/try_identity_e2e.old.PreCodegen.after.mir
new file mode 100644
index 000000000000..18d3e0fb2639
--- /dev/null
+++ b/src/test/mir-opt/try_identity_e2e.old.PreCodegen.after.mir
@@ -0,0 +1,53 @@
+// MIR for `old` after PreCodegen
+
+fn old(_1: Result<T, E>) -> Result<T, E> {
+    debug x => _1;                       // in scope 0 at $DIR/try_identity_e2e.rs:+0:14: +0:15
+    let mut _0: std::result::Result<T, E>; // return place in scope 0 at $DIR/try_identity_e2e.rs:+0:34: +0:46
+    let mut _2: T;                       // in scope 0 at $DIR/try_identity_e2e.rs:+2:9: +5:10
+    let mut _3: isize;                   // in scope 0 at $DIR/try_identity_e2e.rs:+3:13: +3:18
+    let _4: T;                           // in scope 0 at $DIR/try_identity_e2e.rs:+3:16: +3:17
+    let _5: E;                           // in scope 0 at $DIR/try_identity_e2e.rs:+4:17: +4:18
+    let mut _6: E;                       // in scope 0 at $DIR/try_identity_e2e.rs:+4:34: +4:35
+    scope 1 {
+        debug v => _4;                   // in scope 1 at $DIR/try_identity_e2e.rs:+3:16: +3:17
+    }
+    scope 2 {
+        debug e => _5;                   // in scope 2 at $DIR/try_identity_e2e.rs:+4:17: +4:18
+    }
+
+    bb0: {
+        StorageLive(_2);                 // scope 0 at $DIR/try_identity_e2e.rs:+2:9: +5:10
+        _3 = discriminant(_1);           // scope 0 at $DIR/try_identity_e2e.rs:+2:15: +2:16
+        switchInt(move _3) -> [0_isize: bb3, 1_isize: bb1, otherwise: bb2]; // scope 0 at $DIR/try_identity_e2e.rs:+2:9: +2:16
+    }
+
+    bb1: {
+        StorageLive(_5);                 // scope 0 at $DIR/try_identity_e2e.rs:+4:17: +4:18
+        _5 = move ((_1 as Err).0: E);    // scope 0 at $DIR/try_identity_e2e.rs:+4:17: +4:18
+        StorageLive(_6);                 // scope 2 at $DIR/try_identity_e2e.rs:+4:34: +4:35
+        _6 = move _5;                    // scope 2 at $DIR/try_identity_e2e.rs:+4:34: +4:35
+        Deinit(_0);                      // scope 2 at $DIR/try_identity_e2e.rs:+4:30: +4:36
+        ((_0 as Err).0: E) = move _6;    // scope 2 at $DIR/try_identity_e2e.rs:+4:30: +4:36
+        discriminant(_0) = 1;            // scope 2 at $DIR/try_identity_e2e.rs:+4:30: +4:36
+        StorageDead(_6);                 // scope 2 at $DIR/try_identity_e2e.rs:+4:35: +4:36
+        StorageDead(_5);                 // scope 0 at $DIR/try_identity_e2e.rs:+4:35: +4:36
+        StorageDead(_2);                 // scope 0 at $DIR/try_identity_e2e.rs:+6:5: +6:6
+        return;                          // scope 0 at $DIR/try_identity_e2e.rs:+7:1: +7:2
+    }
+
+    bb2: {
+        unreachable;                     // scope 0 at $DIR/try_identity_e2e.rs:+2:15: +2:16
+    }
+
+    bb3: {
+        StorageLive(_4);                 // scope 0 at $DIR/try_identity_e2e.rs:+3:16: +3:17
+        _4 = move ((_1 as Ok).0: T);     // scope 0 at $DIR/try_identity_e2e.rs:+3:16: +3:17
+        _2 = move _4;                    // scope 1 at $DIR/try_identity_e2e.rs:+3:22: +3:23
+        StorageDead(_4);                 // scope 0 at $DIR/try_identity_e2e.rs:+3:22: +3:23
+        Deinit(_0);                      // scope 0 at $DIR/try_identity_e2e.rs:+1:5: +6:6
+        ((_0 as Ok).0: T) = move _2;     // scope 0 at $DIR/try_identity_e2e.rs:+1:5: +6:6
+        discriminant(_0) = 0;            // scope 0 at $DIR/try_identity_e2e.rs:+1:5: +6:6
+        StorageDead(_2);                 // scope 0 at $DIR/try_identity_e2e.rs:+6:5: +6:6
+        return;                          // scope 0 at $DIR/try_identity_e2e.rs:+7:1: +7:2
+    }
+}
diff --git a/src/test/mir-opt/try_identity_e2e.rs b/src/test/mir-opt/try_identity_e2e.rs
new file mode 100644
index 000000000000..00cb80f5035b
--- /dev/null
+++ b/src/test/mir-opt/try_identity_e2e.rs
@@ -0,0 +1,34 @@
+// Track the status of MIR optimizations simplifying `Ok(res?)` for both the old and new desugarings
+// of that syntax.
+
+use std::ops::ControlFlow;
+
+// EMIT_MIR try_identity_e2e.new.PreCodegen.after.mir
+fn new<T, E>(x: Result<T, E>) -> Result<T, E> {
+    Ok(
+        match {
+            match x {
+                Ok(v) => ControlFlow::Continue(v),
+                Err(e) => ControlFlow::Break(e),
+            }
+        } {
+            ControlFlow::Continue(v) => v,
+            ControlFlow::Break(e) => return Err(e),
+        }
+    )
+}
+
+// EMIT_MIR try_identity_e2e.old.PreCodegen.after.mir
+fn old<T, E>(x: Result<T, E>) -> Result<T, E> {
+    Ok(
+        match x {
+            Ok(v) => v,
+            Err(e) => return Err(e),
+        }
+    )
+}
+
+fn main() {
+    let _ = new::<(), ()>(Ok(()));
+    let _ = old::<(), ()>(Ok(()));
+}
diff --git a/src/test/mir-opt/uniform_array_move_out.move_out_by_subslice.mir_map.0.mir b/src/test/mir-opt/uniform_array_move_out.move_out_by_subslice.mir_map.0.mir
index 6e9a8b4d975f..6a5021139cf6 100644
--- a/src/test/mir-opt/uniform_array_move_out.move_out_by_subslice.mir_map.0.mir
+++ b/src/test/mir-opt/uniform_array_move_out.move_out_by_subslice.mir_map.0.mir
@@ -15,9 +15,9 @@ fn move_out_by_subslice() -> () {
     let mut _11: std::boxed::Box<i32>;   // in scope 0 at $DIR/uniform_array_move_out.rs:+1:21: +1:26
     scope 1 {
         debug a => _1;                   // in scope 1 at $DIR/uniform_array_move_out.rs:+1:9: +1:10
-        let _12: [std::boxed::Box<i32>; 2]; // in scope 1 at $DIR/uniform_array_move_out.rs:+2:10: +2:17
+        let _12: [std::boxed::Box<i32>; 2]; // in scope 1 at $DIR/uniform_array_move_out.rs:+2:10: +2:12
         scope 4 {
-            debug _y => _12;             // in scope 4 at $DIR/uniform_array_move_out.rs:+2:10: +2:17
+            debug _y => _12;             // in scope 4 at $DIR/uniform_array_move_out.rs:+2:10: +2:12
         }
     }
     scope 2 {
@@ -77,8 +77,8 @@ fn move_out_by_subslice() -> () {
     bb6: {
         StorageDead(_2);                 // scope 0 at $DIR/uniform_array_move_out.rs:+1:26: +1:27
         FakeRead(ForLet(None), _1);      // scope 0 at $DIR/uniform_array_move_out.rs:+1:9: +1:10
-        StorageLive(_12);                // scope 1 at $DIR/uniform_array_move_out.rs:+2:10: +2:17
-        _12 = move _1[0..2];             // scope 1 at $DIR/uniform_array_move_out.rs:+2:10: +2:17
+        StorageLive(_12);                // scope 1 at $DIR/uniform_array_move_out.rs:+2:10: +2:12
+        _12 = move _1[0..2];             // scope 1 at $DIR/uniform_array_move_out.rs:+2:10: +2:12
         _0 = const ();                   // scope 0 at $DIR/uniform_array_move_out.rs:+0:27: +3:2
         drop(_12) -> [return: bb7, unwind: bb9]; // scope 1 at $DIR/uniform_array_move_out.rs:+3:1: +3:2
     }
diff --git a/src/test/mir-opt/unusual-item-types.rs b/src/test/mir-opt/unusual-item-types.rs
index 670f61cd5ce3..9ef3d86472db 100644
--- a/src/test/mir-opt/unusual-item-types.rs
+++ b/src/test/mir-opt/unusual-item-types.rs
@@ -1,7 +1,7 @@
 // Test that we don't ICE when trying to dump MIR for unusual item types and
 // that we don't create filenames containing `<` and `>`
 // compile-flags: -Zmir-opt-level=0
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
+
 
 struct A;
 
diff --git a/src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.64bit.mir b/src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.64bit.mir
deleted file mode 100644
index a72e00ecde75..000000000000
--- a/src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,10 +0,0 @@
-// MIR for `E::V::{constant#0}` 0 mir_map
-
-E::V::{constant#0}: isize = {
-    let mut _0: isize;                   // return place in scope 0 at $DIR/unusual-item-types.rs:+0:9: +0:10
-
-    bb0: {
-        _0 = const 5_isize;              // scope 0 at $DIR/unusual-item-types.rs:+0:9: +0:10
-        return;                          // scope 0 at $DIR/unusual-item-types.rs:+0:9: +0:10
-    }
-}
diff --git a/src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.32bit.mir b/src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.mir
similarity index 100%
rename from src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.32bit.mir
rename to src/test/mir-opt/unusual_item_types.E-V-{constant#0}.mir_map.0.mir
diff --git a/src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.64bit.mir b/src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.64bit.mir
deleted file mode 100644
index 0686af46ed58..000000000000
--- a/src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,12 +0,0 @@
-// MIR for `Test::X` 0 mir_map
-
-fn Test::X(_1: usize) -> Test {
-    let mut _0: Test;                    // return place in scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:6
-
-    bb0: {
-        Deinit(_0);                      // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:6
-        ((_0 as X).0: usize) = move _1;  // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:6
-        discriminant(_0) = 0;            // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:6
-        return;                          // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:6
-    }
-}
diff --git a/src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.32bit.mir b/src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.mir
similarity index 100%
rename from src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.32bit.mir
rename to src/test/mir-opt/unusual_item_types.Test-X-{constructor#0}.mir_map.0.mir
diff --git a/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.32bit.mir b/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.32bit.mir
deleted file mode 100644
index 7ffd242e0dc3..000000000000
--- a/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.32bit.mir
+++ /dev/null
@@ -1,39 +0,0 @@
-// MIR for `std::ptr::drop_in_place` before AddMovesForPackedDrops
-
-fn std::ptr::drop_in_place(_1: *mut Vec<i32>) -> () {
-    let mut _0: ();                      // return place in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _2: &mut std::vec::Vec<i32>; // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _3: ();                      // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-
-    bb0: {
-        goto -> bb6;                     // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb1: {
-        return;                          // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb2 (cleanup): {
-        resume;                          // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb3: {
-        goto -> bb1;                     // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb4 (cleanup): {
-        drop(((*_1).0: alloc::raw_vec::RawVec<i32>)) -> bb2; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb5: {
-        drop(((*_1).0: alloc::raw_vec::RawVec<i32>)) -> [return: bb3, unwind: bb2]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    }
-
-    bb6: {
-        _2 = &mut (*_1);                 // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _3 = <Vec<i32> as Drop>::drop(move _2) -> [return: bb5, unwind: bb4]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-                                         // mir::Constant
-                                         // + span: $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r> fn(&'r mut Vec<i32>) {<Vec<i32> as Drop>::drop}, val: Value(<ZST>) }
-    }
-}
diff --git a/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.64bit.mir b/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.mir
similarity index 96%
rename from src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.64bit.mir
rename to src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.mir
index 7ffd242e0dc3..ed9f3bdbdf4d 100644
--- a/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.64bit.mir
+++ b/src/test/mir-opt/unusual_item_types.core.ptr-drop_in_place.Vec_i32_.AddMovesForPackedDrops.before.mir
@@ -34,6 +34,6 @@ fn std::ptr::drop_in_place(_1: *mut Vec<i32>) -> () {
         _3 = <Vec<i32> as Drop>::drop(move _2) -> [return: bb5, unwind: bb4]; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'r> fn(&'r mut Vec<i32>) {<Vec<i32> as Drop>::drop}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a> fn(&'a mut Vec<i32>) {<Vec<i32> as Drop>::drop}, val: Value(<ZST>) }
     }
 }
diff --git a/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.64bit.mir b/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.64bit.mir
deleted file mode 100644
index e2633f61b5fe..000000000000
--- a/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.64bit.mir
+++ /dev/null
@@ -1,10 +0,0 @@
-// MIR for `<impl at $DIR/unusual-item-types.rs:9:1: 9:7>::ASSOCIATED_CONSTANT` 0 mir_map
-
-const <impl at $DIR/unusual-item-types.rs:9:1: 9:7>::ASSOCIATED_CONSTANT: i32 = {
-    let mut _0: i32;                     // return place in scope 0 at $DIR/unusual-item-types.rs:+0:32: +0:35
-
-    bb0: {
-        _0 = const 2_i32;                // scope 0 at $DIR/unusual-item-types.rs:+0:38: +0:39
-        return;                          // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:39
-    }
-}
diff --git a/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.32bit.mir b/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.mir
similarity index 93%
rename from src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.32bit.mir
rename to src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.mir
index e2633f61b5fe..5579d25a14fd 100644
--- a/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.32bit.mir
+++ b/src/test/mir-opt/unusual_item_types.{impl#0}-ASSOCIATED_CONSTANT.mir_map.0.mir
@@ -5,6 +5,6 @@ const <impl at $DIR/unusual-item-types.rs:9:1: 9:7>::ASSOCIATED_CONSTANT: i32 =
 
     bb0: {
         _0 = const 2_i32;                // scope 0 at $DIR/unusual-item-types.rs:+0:38: +0:39
-        return;                          // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:39
+        return;                          // scope 0 at $DIR/unusual-item-types.rs:+0:5: +0:40
     }
 }
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff b/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff
deleted file mode 100644
index eef7011149d3..000000000000
--- a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff
+++ /dev/null
@@ -1,55 +0,0 @@
-- // MIR for `change_loop_body` before ConstProp
-+ // MIR for `change_loop_body` after ConstProp
-  
-  fn change_loop_body() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/while_let_loops.rs:+0:27: +0:27
-      let mut _1: i32;                     // in scope 0 at $DIR/while_let_loops.rs:+1:9: +1:15
-      let mut _2: ();                      // in scope 0 at $DIR/while_let_loops.rs:+0:1: +6:2
-      let mut _3: std::option::Option<u32>; // in scope 0 at $DIR/while_let_loops.rs:+2:28: +2:32
-      let mut _4: isize;                   // in scope 0 at $DIR/while_let_loops.rs:+2:15: +2:25
-      let mut _5: !;                       // in scope 0 at $DIR/while_let_loops.rs:+2:33: +5:6
-      let mut _6: !;                       // in scope 0 at $DIR/while_let_loops.rs:+2:5: +5:6
-      let _7: ();                          // in scope 0 at $DIR/while_let_loops.rs:+2:5: +5:6
-      let mut _8: !;                       // in scope 0 at $DIR/while_let_loops.rs:+2:5: +5:6
-      scope 1 {
-          debug _x => _1;                  // in scope 1 at $DIR/while_let_loops.rs:+1:9: +1:15
-          scope 2 {
-          }
-      }
-  
-      bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/while_let_loops.rs:+1:9: +1:15
-          _1 = const 0_i32;                // scope 0 at $DIR/while_let_loops.rs:+1:18: +1:19
-          StorageLive(_3);                 // scope 2 at $DIR/while_let_loops.rs:+2:28: +2:32
-          Deinit(_3);                      // scope 2 at $DIR/while_let_loops.rs:+2:28: +2:32
-          discriminant(_3) = 0;            // scope 2 at $DIR/while_let_loops.rs:+2:28: +2:32
--         _4 = discriminant(_3);           // scope 2 at $DIR/while_let_loops.rs:+2:15: +2:25
--         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:+2:15: +2:25
-+         _4 = const 0_isize;              // scope 2 at $DIR/while_let_loops.rs:+2:15: +2:25
-+         switchInt(const 0_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:+2:15: +2:25
-      }
-  
-      bb1: {
-          switchInt(((_3 as Some).0: u32)) -> [0_u32: bb2, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:+2:15: +2:25
-      }
-  
-      bb2: {
-          _1 = const 1_i32;                // scope 2 at $DIR/while_let_loops.rs:+3:9: +3:15
-          nop;                             // scope 2 at $DIR/while_let_loops.rs:+4:9: +4:14
-          goto -> bb4;                     // scope 2 at $DIR/while_let_loops.rs:+4:9: +4:14
-      }
-  
-      bb3: {
-          StorageLive(_7);                 // scope 1 at $DIR/while_let_loops.rs:+2:5: +5:6
-          nop;                             // scope 1 at $DIR/while_let_loops.rs:+2:5: +5:6
-          StorageDead(_7);                 // scope 1 at $DIR/while_let_loops.rs:+5:5: +5:6
-          goto -> bb4;                     // scope 1 at no-location
-      }
-  
-      bb4: {
-          StorageDead(_3);                 // scope 1 at $DIR/while_let_loops.rs:+5:5: +5:6
-          StorageDead(_1);                 // scope 0 at $DIR/while_let_loops.rs:+6:1: +6:2
-          return;                          // scope 0 at $DIR/while_let_loops.rs:+6:2: +6:2
-      }
-  }
-  
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.32bit.diff b/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.diff
similarity index 100%
rename from src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.32bit.diff
rename to src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.diff
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir b/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir
deleted file mode 100644
index 15b0aece8f54..000000000000
--- a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir
+++ /dev/null
@@ -1,17 +0,0 @@
-// MIR for `change_loop_body` after PreCodegen
-
-fn change_loop_body() -> () {
-    let mut _0: ();                      // return place in scope 0 at $DIR/while_let_loops.rs:+0:27: +0:27
-    let mut _1: i32;                     // in scope 0 at $DIR/while_let_loops.rs:+1:9: +1:15
-    scope 1 {
-        debug _x => _1;                  // in scope 1 at $DIR/while_let_loops.rs:+1:9: +1:15
-        scope 2 {
-        }
-    }
-
-    bb0: {
-        StorageLive(_1);                 // scope 0 at $DIR/while_let_loops.rs:+1:9: +1:15
-        StorageDead(_1);                 // scope 0 at $DIR/while_let_loops.rs:+6:1: +6:2
-        return;                          // scope 0 at $DIR/while_let_loops.rs:+6:2: +6:2
-    }
-}
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir b/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.mir
similarity index 100%
rename from src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir
rename to src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.mir
diff --git a/src/test/mir-opt/while_let_loops.rs b/src/test/mir-opt/while_let_loops.rs
index f320a218c852..fc56cd6985d6 100644
--- a/src/test/mir-opt/while_let_loops.rs
+++ b/src/test/mir-opt/while_let_loops.rs
@@ -1,6 +1,5 @@
 // EMIT_MIR while_let_loops.change_loop_body.ConstProp.diff
 // EMIT_MIR while_let_loops.change_loop_body.PreCodegen.after.mir
-// EMIT_MIR_FOR_EACH_BIT_WIDTH
 
 pub fn change_loop_body() {
     let mut _x = 0;
diff --git a/src/test/pretty/gat-bounds.rs b/src/test/pretty/gat-bounds.rs
index 8877c6cc9927..0a361a3835f7 100644
--- a/src/test/pretty/gat-bounds.rs
+++ b/src/test/pretty/gat-bounds.rs
@@ -3,8 +3,6 @@
 
 // pretty-compare-only
 
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<T>: Trait where Self: Sized;
 }
diff --git a/src/test/pretty/issue-4264.pp b/src/test/pretty/issue-4264.pp
index 752c36a0fbc5..18e6d75b1d5a 100644
--- a/src/test/pretty/issue-4264.pp
+++ b/src/test/pretty/issue-4264.pp
@@ -32,12 +32,12 @@ fn bar() ({
         ({
                 let res =
                     ((::alloc::fmt::format as
-                            for<'r> fn(Arguments<'r>) -> String {format})(((::core::fmt::Arguments::new_v1
+                            for<'a> fn(Arguments<'a>) -> String {format})(((::core::fmt::Arguments::new_v1
                                 as
-                                fn(&[&'static str], &[ArgumentV1]) -> Arguments {Arguments::new_v1})((&([("test"
+                                fn(&[&'static str], &[ArgumentV1<'_>]) -> Arguments<'_> {Arguments::<'_>::new_v1})((&([("test"
                                             as &str)] as [&str; 1]) as &[&str; 1]),
-                            (&([] as [ArgumentV1; 0]) as &[ArgumentV1; 0])) as
-                            Arguments)) as String);
+                            (&([] as [ArgumentV1<'_>; 0]) as &[ArgumentV1<'_>; 0])) as
+                            Arguments<'_>)) as String);
                 (res as String)
             } as String);
     } as ())
diff --git a/src/test/run-make-fulldeps/alloc-no-rc/Makefile b/src/test/run-make-fulldeps/alloc-no-rc/Makefile
new file mode 100644
index 000000000000..5f7ae70fa026
--- /dev/null
+++ b/src/test/run-make-fulldeps/alloc-no-rc/Makefile
@@ -0,0 +1,4 @@
+include ../tools.mk
+
+all:
+	$(RUSTC) --edition=2021 -Dwarnings --crate-type=rlib ../../../../library/alloc/src/lib.rs --cfg no_rc
diff --git a/src/test/run-make-fulldeps/alloc-no-sync/Makefile b/src/test/run-make-fulldeps/alloc-no-sync/Makefile
new file mode 100644
index 000000000000..6a258a2ddfd6
--- /dev/null
+++ b/src/test/run-make-fulldeps/alloc-no-sync/Makefile
@@ -0,0 +1,4 @@
+include ../tools.mk
+
+all:
+	$(RUSTC) --edition=2021 -Dwarnings --crate-type=rlib ../../../../library/alloc/src/lib.rs --cfg no_sync
diff --git a/src/test/run-make-fulldeps/issue-64153/Makefile b/src/test/run-make-fulldeps/issue-64153/Makefile
index 51dc6b53a450..f42ea620fb9d 100644
--- a/src/test/run-make-fulldeps/issue-64153/Makefile
+++ b/src/test/run-make-fulldeps/issue-64153/Makefile
@@ -19,7 +19,7 @@ all:
 	# Dump all the symbols from the staticlib into `syms`
 	"$(LLVM_BIN_DIR)"/llvm-objdump -t $(TMPDIR)/libdownstream.a > $(TMPDIR)/syms
 	# Count the global instances of `issue64153_test_function`. There'll be 2
-	# if the `upstream` object file got erronously included twice.
+	# if the `upstream` object file got erroneously included twice.
 	# The line we are testing for with the regex looks something like:
 	# 0000000000000000 g     F .text.issue64153_test_function	00000023 issue64153_test_function
 	grep -c -e "[[:space:]]g[[:space:]]*F[[:space:]].*issue64153_test_function" $(TMPDIR)/syms > $(TMPDIR)/count
diff --git a/src/test/run-make-fulldeps/issue-97463-abi-param-passing/Makefile b/src/test/run-make-fulldeps/issue-97463-abi-param-passing/Makefile
new file mode 100644
index 000000000000..db1b53e152ea
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue-97463-abi-param-passing/Makefile
@@ -0,0 +1,14 @@
+-include ../tools.mk
+
+# ignore-msvc
+
+# The issue exercised by this test, rust-lang/rust#97463, explicitly needs `-O`
+# flags (like `-O3`) to reproduce. Thus, we call $(CC) instead of nicer
+# alternatives provided by tools.mk like using `COMPILE_OBJ` or using a
+# `NATIVE_STATICLIB` dependency.
+
+all:
+	$(CC) -c -O3 -o $(TMPDIR)/bad.o bad.c
+	$(AR) rcs $(TMPDIR)/libbad.a $(TMPDIR)/bad.o
+	$(RUSTC) param_passing.rs -L$(TMPDIR) -lbad -C opt-level=3
+	$(call RUN,param_passing)
diff --git a/src/test/run-make-fulldeps/issue-97463-abi-param-passing/bad.c b/src/test/run-make-fulldeps/issue-97463-abi-param-passing/bad.c
new file mode 100644
index 000000000000..013314ab20dc
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue-97463-abi-param-passing/bad.c
@@ -0,0 +1,24 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+
+
+struct bloc {
+    uint16_t a;
+    uint16_t b;
+    uint16_t c;
+};
+
+uint16_t c_read_value(uint32_t a, uint32_t b, uint32_t c) {
+    struct bloc *data = malloc(sizeof(struct bloc));
+
+    data->a = a & 0xFFFF;
+    data->b = b & 0xFFFF;
+    data->c = c & 0xFFFF;
+
+    printf("C struct: a = %u, b = %u, c = %u\n",
+        (unsigned) data->a, (unsigned) data->b, (unsigned) data->c);
+    printf("C function returns %u\n", (unsigned) data->b);
+
+    return data->b; /* leak data */
+}
diff --git a/src/test/run-make-fulldeps/issue-97463-abi-param-passing/param_passing.rs b/src/test/run-make-fulldeps/issue-97463-abi-param-passing/param_passing.rs
new file mode 100644
index 000000000000..c11f3cc72bdf
--- /dev/null
+++ b/src/test/run-make-fulldeps/issue-97463-abi-param-passing/param_passing.rs
@@ -0,0 +1,38 @@
+// NOTE: Exposing the bug encoded in this test is sensitive to
+// LLVM optimization choices. See additional note below for an
+// example.
+
+#[link(name = "bad")]
+extern "C" {
+    pub fn c_read_value(a: u32, b: u32, c: u32) -> u16;
+}
+
+fn main() {
+    const C1: usize = 0x327b23c6;
+    const C2: usize = C1 & 0xFFFF;
+
+    let r1: usize = 0x0;
+    let r2: usize = C1;
+    let r3: usize = 0x0;
+    let value: u16 = unsafe { c_read_value(r1 as u32, r2 as u32, r3 as u32) };
+
+    // NOTE: as an example of the sensitivity of this test to optimization choices,
+    // uncommenting this block of code makes the bug go away on pnkfelix's machine.
+    // (But observing via `dbg!` doesn't hide the bug. At least sometimes.)
+    /*
+    println!("{}", value);
+    println!("{}", value as usize);
+    println!("{}", usize::from(value));
+    println!("{}", (value as usize) & 0xFFFF);
+     */
+
+    let d1 = value;
+    let d2 = value as usize;
+    let d3 = usize::from(value);
+    let d4 = (value as usize) & 0xFFFF;
+
+    let d = (&d1, &d2, &d3, &d4);
+    let d_ = (d1, d2, d3, d4);
+
+    assert_eq!(((&(C2 as u16), &C2, &C2, &C2), (C2 as u16, C2, C2, C2)), (d, d_));
+}
diff --git a/src/test/run-make-fulldeps/print-calling-conventions/Makefile b/src/test/run-make-fulldeps/print-calling-conventions/Makefile
new file mode 100644
index 000000000000..d3fd06392b0e
--- /dev/null
+++ b/src/test/run-make-fulldeps/print-calling-conventions/Makefile
@@ -0,0 +1,4 @@
+-include ../tools.mk
+
+all:
+	$(RUSTC) --print calling-conventions
diff --git a/src/test/run-make/coverage-reports/Makefile b/src/test/run-make/coverage-reports/Makefile
index cac881ece129..6fc2a6bada9a 100644
--- a/src/test/run-make/coverage-reports/Makefile
+++ b/src/test/run-make/coverage-reports/Makefile
@@ -60,7 +60,7 @@ endif
 # for now, but it is effectively ignored for all tests that don't include this file anyway.
 #
 # (Note that it's also possible the `_counters.<test>.txt` and `<test>.json` files (if generated)
-# may order results from multiple files inconsistently, which might also have to be accomodated
+# may order results from multiple files inconsistently, which might also have to be accommodated
 # if and when we allow `llvm-cov` to produce results for multiple files. Note, the path separators
 # appear to be normalized to `/` in those files, thankfully.)
 LLVM_COV_IGNORE_FILES=\
@@ -157,7 +157,7 @@ else
 	# `// ignore-llvm-cov-show-diffs` anymore. This directive exists to work around a limitation
 	# with `llvm-cov show`. When reporting coverage for multiple instantiations of a generic function,
 	# with different type substitutions, `llvm-cov show` prints these in a non-deterministic order,
-	# breaking the `diff` comparision.
+	# breaking the `diff` comparison.
 	#
 	# A partial workaround is implemented below, with `diff --ignore-matching-lines=RE`
 	# to ignore each line prefixing each generic instantiation coverage code region.
diff --git a/src/test/run-make/coverage-reports/expected_show_coverage.async.txt b/src/test/run-make/coverage-reports/expected_show_coverage.async.txt
index 2f69adbd81c5..87ccb6c43eab 100644
--- a/src/test/run-make/coverage-reports/expected_show_coverage.async.txt
+++ b/src/test/run-make/coverage-reports/expected_show_coverage.async.txt
@@ -55,7 +55,7 @@
    53|      1|            1 // This line appears covered, but the 1-character expression span covering the `1`
                           ^0
    54|      1|              // is not executed. (`llvm-cov show` displays a `^0` below the `1` ). This is because
-   55|      1|              // `fn j()` executes the open brace for the funciton body, followed by the function's
+   55|      1|              // `fn j()` executes the open brace for the function body, followed by the function's
    56|      1|              // first executable statement, `match x`. Inner function declarations are not
    57|      1|              // "visible" to the MIR for `j()`, so the code region counts all lines between the
    58|      1|              // open brace and the first statement as executed, which is, in a sense, true.
diff --git a/src/test/run-make/coverage-reports/expected_show_coverage.closure.txt b/src/test/run-make/coverage-reports/expected_show_coverage.closure.txt
index 09ad276aa45a..e463099a5ee4 100644
--- a/src/test/run-make/coverage-reports/expected_show_coverage.closure.txt
+++ b/src/test/run-make/coverage-reports/expected_show_coverage.closure.txt
@@ -37,7 +37,7 @@
    37|      0|            countdown = 10;
    38|      0|        }
    39|      0|        "alt string 2".to_owned()
-   40|       |    };
+   40|      0|    };
    41|      1|    println!(
    42|      1|        "The string or alt: {}"
    43|      1|        ,
@@ -79,7 +79,7 @@
    79|      0|            countdown = 10;
    80|      1|        }
    81|      1|        "alt string 4".to_owned()
-   82|       |    };
+   82|      1|    };
    83|      1|    println!(
    84|      1|        "The string or alt: {}"
    85|      1|        ,
@@ -101,7 +101,7 @@
   101|      0|            countdown = 10;
   102|      5|        }
   103|      5|        format!("'{}'", val)
-  104|       |    };
+  104|      5|    };
   105|      1|    println!(
   106|      1|        "Repeated, quoted string: {:?}"
   107|      1|        ,
@@ -125,7 +125,7 @@
   125|      0|            countdown = 10;
   126|      0|        }
   127|      0|        "closure should be unused".to_owned()
-  128|       |    };
+  128|      0|    };
   129|       |
   130|      1|    let mut countdown = 10;
   131|      1|    let _short_unused_closure = | _unused_arg: u8 | countdown += 1;
@@ -177,7 +177,7 @@
   173|      0|            println!(
   174|      0|                "not called: {}",
   175|      0|                if is_true { "check" } else { "me" }
-  176|       |            )
+  176|      0|            )
   177|       |    ;
   178|       |
   179|      1|    let short_used_not_covered_closure_line_break_block_embedded_branch =
@@ -187,7 +187,7 @@
   183|      0|                "not called: {}",
   184|      0|                if is_true { "check" } else { "me" }
   185|       |            )
-  186|       |        }
+  186|      0|        }
   187|       |    ;
   188|       |
   189|      1|    let short_used_covered_closure_line_break_no_block_embedded_branch =
@@ -196,7 +196,7 @@
   192|      1|                "not called: {}",
   193|      1|                if is_true { "check" } else { "me" }
                                                             ^0
-  194|       |            )
+  194|      1|            )
   195|       |    ;
   196|       |
   197|      1|    let short_used_covered_closure_line_break_block_embedded_branch =
@@ -207,7 +207,7 @@
   202|      1|                if is_true { "check" } else { "me" }
                                                             ^0
   203|       |            )
-  204|       |        }
+  204|      1|        }
   205|       |    ;
   206|       |
   207|      1|    if is_false {
diff --git a/src/test/run-make/coverage-reports/expected_show_coverage.generator.txt b/src/test/run-make/coverage-reports/expected_show_coverage.generator.txt
index d70e12e4128b..0fb3808ff2e3 100644
--- a/src/test/run-make/coverage-reports/expected_show_coverage.generator.txt
+++ b/src/test/run-make/coverage-reports/expected_show_coverage.generator.txt
@@ -18,7 +18,7 @@
    17|      1|    let mut generator = || {
    18|      1|        yield get_u32(is_true);
    19|      1|        return "foo";
-   20|       |    };
+   20|      1|    };
    21|       |
    22|      1|    match Pin::new(&mut generator).resume(()) {
    23|      1|        GeneratorState::Yielded(Ok(1)) => {}
diff --git a/src/test/run-make/coverage-reports/expected_show_coverage.inline-dead.txt b/src/test/run-make/coverage-reports/expected_show_coverage.inline-dead.txt
index effdef80e8eb..a59fe1146f48 100644
--- a/src/test/run-make/coverage-reports/expected_show_coverage.inline-dead.txt
+++ b/src/test/run-make/coverage-reports/expected_show_coverage.inline-dead.txt
@@ -6,7 +6,7 @@
     6|      1|
     7|      1|    let f = |x: bool| {
     8|       |        debug_assert!(
-    9|       |            x
+    9|      0|            x
    10|       |        );
    11|      1|    };
    12|      1|    f(false);
diff --git a/src/test/run-make/coverage-reports/expected_show_coverage.uses_inline_crate.txt b/src/test/run-make/coverage-reports/expected_show_coverage.uses_inline_crate.txt
index dab31cbf4ac9..748343885de1 100644
--- a/src/test/run-make/coverage-reports/expected_show_coverage.uses_inline_crate.txt
+++ b/src/test/run-make/coverage-reports/expected_show_coverage.uses_inline_crate.txt
@@ -61,12 +61,12 @@
    46|      4|    println!("used_only_from_this_lib_crate_generic_function with {:?}", arg);
    47|      4|}
   ------------------
-  | used_inline_crate::used_only_from_this_lib_crate_generic_function::<alloc::vec::Vec<i32>>:
+  | used_inline_crate::used_only_from_this_lib_crate_generic_function::<&str>:
   |   45|      2|pub fn used_only_from_this_lib_crate_generic_function<T: Debug>(arg: T) {
   |   46|      2|    println!("used_only_from_this_lib_crate_generic_function with {:?}", arg);
   |   47|      2|}
   ------------------
-  | used_inline_crate::used_only_from_this_lib_crate_generic_function::<&str>:
+  | used_inline_crate::used_only_from_this_lib_crate_generic_function::<alloc::vec::Vec<i32>>:
   |   45|      2|pub fn used_only_from_this_lib_crate_generic_function<T: Debug>(arg: T) {
   |   46|      2|    println!("used_only_from_this_lib_crate_generic_function with {:?}", arg);
   |   47|      2|}
diff --git a/src/test/run-make/coverage-reports/expected_show_coverage.yield.txt b/src/test/run-make/coverage-reports/expected_show_coverage.yield.txt
index 60a8d943f1fe..6e2f23ee77b8 100644
--- a/src/test/run-make/coverage-reports/expected_show_coverage.yield.txt
+++ b/src/test/run-make/coverage-reports/expected_show_coverage.yield.txt
@@ -8,7 +8,7 @@
     8|      1|    let mut generator = || {
     9|      1|        yield 1;
    10|      1|        return "foo"
-   11|       |    };
+   11|      1|    };
    12|       |
    13|      1|    match Pin::new(&mut generator).resume(()) {
    14|      1|        GeneratorState::Yielded(1) => {}
@@ -24,7 +24,7 @@
    24|      1|        yield 2;
    25|      0|        yield 3;
    26|      0|        return "foo"
-   27|       |    };
+   27|      0|    };
    28|       |
    29|      1|    match Pin::new(&mut generator).resume(()) {
    30|      1|        GeneratorState::Yielded(1) => {}
diff --git a/src/test/run-make/coverage/async.rs b/src/test/run-make/coverage/async.rs
index a6e387747068..efd9e62d64e1 100644
--- a/src/test/run-make/coverage/async.rs
+++ b/src/test/run-make/coverage/async.rs
@@ -52,7 +52,7 @@ fn j(x: u8) {
         if x == 8 {
             1 // This line appears covered, but the 1-character expression span covering the `1`
               // is not executed. (`llvm-cov show` displays a `^0` below the `1` ). This is because
-              // `fn j()` executes the open brace for the funciton body, followed by the function's
+              // `fn j()` executes the open brace for the function body, followed by the function's
               // first executable statement, `match x`. Inner function declarations are not
               // "visible" to the MIR for `j()`, so the code region counts all lines between the
               // open brace and the first statement as executed, which is, in a sense, true.
diff --git a/src/test/run-make/issue-71519/Makefile b/src/test/run-make/issue-71519/Makefile
index 4475649ca927..16d9a56e6bf7 100644
--- a/src/test/run-make/issue-71519/Makefile
+++ b/src/test/run-make/issue-71519/Makefile
@@ -1,5 +1,6 @@
 include ../../run-make-fulldeps/tools.mk
 
+# ignore-msvc
 # needs-rust-lld
 all:
 	RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Z gcc-ld=lld -C link-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt
diff --git a/src/test/run-make/native-link-modifier-verbatim-linker/Makefile b/src/test/run-make/native-link-modifier-verbatim-linker/Makefile
new file mode 100644
index 000000000000..e56e1e94ec5b
--- /dev/null
+++ b/src/test/run-make/native-link-modifier-verbatim-linker/Makefile
@@ -0,0 +1,15 @@
+# ignore-cross-compile
+# ignore-macos
+
+include ../../run-make-fulldeps/tools.mk
+
+all:
+	# Verbatim allows specify precise name.
+	$(RUSTC) local_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/local_some_strange_name.ext
+	$(RUSTC) main.rs -Zunstable-options -l static:+verbatim=local_some_strange_name.ext
+
+	# With verbatim any other name cannot be used (local).
+	$(RUSTC) local_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/liblocal_native_dep.a
+	$(RUSTC) local_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/local_native_dep.a
+	$(RUSTC) local_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/local_native_dep.lib
+	$(RUSTC) main.rs -Zunstable-options -l static:+verbatim=local_native_dep 2>&1 | $(CGREP) "local_native_dep"
diff --git a/src/test/run-make/native-link-modifier-verbatim-linker/local_native_dep.rs b/src/test/run-make/native-link-modifier-verbatim-linker/local_native_dep.rs
new file mode 100644
index 000000000000..59b6c92d2936
--- /dev/null
+++ b/src/test/run-make/native-link-modifier-verbatim-linker/local_native_dep.rs
@@ -0,0 +1,4 @@
+#[no_mangle]
+pub fn local_native_f() -> i32 {
+    return 0;
+}
diff --git a/src/test/run-make/native-link-modifier-verbatim-linker/main.rs b/src/test/run-make/native-link-modifier-verbatim-linker/main.rs
new file mode 100644
index 000000000000..71b73a489c76
--- /dev/null
+++ b/src/test/run-make/native-link-modifier-verbatim-linker/main.rs
@@ -0,0 +1,9 @@
+extern "C" {
+    fn local_native_f() -> i32;
+}
+
+pub fn main() {
+    unsafe {
+        assert!(local_native_f() == 0);
+    };
+}
diff --git a/src/test/run-make/native-link-modifier-verbatim-rustc/Makefile b/src/test/run-make/native-link-modifier-verbatim-rustc/Makefile
new file mode 100644
index 000000000000..1093b1cd3694
--- /dev/null
+++ b/src/test/run-make/native-link-modifier-verbatim-rustc/Makefile
@@ -0,0 +1,12 @@
+include ../../run-make-fulldeps/tools.mk
+
+all:
+	# Verbatim allows specify precise name.
+	$(RUSTC) upstream_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/upstream_some_strange_name.ext
+	$(RUSTC) rust_dep.rs -Zunstable-options -l static:+verbatim=upstream_some_strange_name.ext --crate-type rlib
+
+	# With verbatim any other name cannot be used (upstream).
+	$(RUSTC) upstream_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/libupstream_native_dep.a
+	$(RUSTC) upstream_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/upstream_native_dep.a
+	$(RUSTC) upstream_native_dep.rs --crate-type=staticlib -o $(TMPDIR)/upstream_native_dep.lib
+	$(RUSTC) rust_dep.rs -Zunstable-options -l static:+verbatim=upstream_native_dep --crate-type rlib 2>&1 | $(CGREP) "upstream_native_dep"
diff --git a/src/test/run-make/native-link-modifier-verbatim-rustc/rust_dep.rs b/src/test/run-make/native-link-modifier-verbatim-rustc/rust_dep.rs
new file mode 100644
index 000000000000..e9517218e0db
--- /dev/null
+++ b/src/test/run-make/native-link-modifier-verbatim-rustc/rust_dep.rs
@@ -0,0 +1,9 @@
+extern "C" {
+    fn upstream_native_f() -> i32;
+}
+
+pub fn rust_dep() {
+    unsafe {
+        assert!(upstream_native_f() == 0);
+    }
+}
diff --git a/src/test/run-make/native-link-modifier-verbatim-rustc/upstream_native_dep.rs b/src/test/run-make/native-link-modifier-verbatim-rustc/upstream_native_dep.rs
new file mode 100644
index 000000000000..8396862333dc
--- /dev/null
+++ b/src/test/run-make/native-link-modifier-verbatim-rustc/upstream_native_dep.rs
@@ -0,0 +1,4 @@
+#[no_mangle]
+pub fn upstream_native_f() -> i32 {
+    return 0;
+}
diff --git a/src/test/run-make/raw-dylib-alt-calling-convention/extern.c b/src/test/run-make/raw-dylib-alt-calling-convention/extern.c
index 0c4d12af9b2c..344d4a6bf5a8 100644
--- a/src/test/run-make/raw-dylib-alt-calling-convention/extern.c
+++ b/src/test/run-make/raw-dylib-alt-calling-convention/extern.c
@@ -70,6 +70,11 @@ __declspec(dllexport) void __stdcall stdcall_fn_9(uint8_t x, double y) {
     fflush(stdout);
 }
 
+__declspec(dllexport) void __stdcall stdcall_fn_10(int i) {
+    printf("stdcall_fn_10(%d)\n", i);
+    fflush(stdout);
+}
+
 __declspec(dllexport) void __fastcall fastcall_fn_1(int i) {
     printf("fastcall_fn_1(%d)\n", i);
     fflush(stdout);
@@ -122,6 +127,11 @@ __declspec(dllexport) void __fastcall fastcall_fn_9(uint8_t x, double y) {
     fflush(stdout);
 }
 
+__declspec(dllexport) void __fastcall fastcall_fn_10(int i) {
+    printf("fastcall_fn_10(%d)\n", i);
+    fflush(stdout);
+}
+
 // GCC doesn't support vectorcall: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89485
 #ifdef _MSC_VER
 __declspec(dllexport) void __vectorcall vectorcall_fn_1(int i) {
@@ -175,4 +185,9 @@ __declspec(dllexport) void __vectorcall vectorcall_fn_9(uint8_t x, double y) {
     printf("vectorcall_fn_9(%d, %.1f)\n", x, y);
     fflush(stdout);
 }
+
+__declspec(dllexport) void __vectorcall vectorcall_fn_10(int i) {
+    printf("vectorcall_fn_10(%d)\n", i);
+    fflush(stdout);
+}
 #endif
diff --git a/src/test/run-make/raw-dylib-alt-calling-convention/lib.rs b/src/test/run-make/raw-dylib-alt-calling-convention/lib.rs
index b5e9415b2bec..22f222c12c39 100644
--- a/src/test/run-make/raw-dylib-alt-calling-convention/lib.rs
+++ b/src/test/run-make/raw-dylib-alt-calling-convention/lib.rs
@@ -1,5 +1,5 @@
-#![feature(raw_dylib)]
 #![feature(abi_vectorcall)]
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[repr(C)]
 #[derive(Clone)]
@@ -32,6 +32,8 @@ extern "stdcall" {
     fn stdcall_fn_7(a: S2, b: i32);
     fn stdcall_fn_8(a: S3, b: S3);
     fn stdcall_fn_9(x: u8, y: f64);
+    #[link_name = "stdcall_fn_10"]
+    fn stdcall_fn_10_renamed(i: i32);
 }
 
 #[link(name = "extern", kind = "raw-dylib")]
@@ -45,6 +47,8 @@ extern "fastcall" {
     fn fastcall_fn_7(a: S2, b: i32);
     fn fastcall_fn_8(a: S3, b: S3);
     fn fastcall_fn_9(x: u8, y: f64);
+    #[link_name = "fastcall_fn_10"]
+    fn fastcall_fn_10_renamed(i: i32);
 }
 
 #[cfg(target_env = "msvc")]
@@ -59,6 +63,8 @@ extern "vectorcall" {
     fn vectorcall_fn_7(a: S2, b: i32);
     fn vectorcall_fn_8(a: S3, b: S3);
     fn vectorcall_fn_9(x: u8, y: f64);
+    #[link_name = "vectorcall_fn_10"]
+    fn vectorcall_fn_10_renamed(i: i32);
 }
 
 pub fn library_function(run_msvc_only: bool) {
@@ -73,6 +79,7 @@ pub fn library_function(run_msvc_only: bool) {
             stdcall_fn_7(S2 { x: 15, y: 16 }, 3);
             stdcall_fn_8(S3 { x: [1, 2, 3, 4, 5] }, S3 { x: [6, 7, 8, 9, 10] });
             stdcall_fn_9(1, 3.0);
+            stdcall_fn_10_renamed(19);
 
             fastcall_fn_1(14);
             fastcall_fn_2(16, 3.5);
@@ -81,6 +88,7 @@ pub fn library_function(run_msvc_only: bool) {
             fastcall_fn_6(Some(&S { x: 10, y: 12 }));
             fastcall_fn_8(S3 { x: [1, 2, 3, 4, 5] }, S3 { x: [6, 7, 8, 9, 10] });
             fastcall_fn_9(1, 3.0);
+            fastcall_fn_10_renamed(19);
         } else {
             // FIXME: 91167
             // rustc generates incorrect code for the calls to fastcall_fn_5 and fastcall_fn_7
@@ -100,6 +108,7 @@ pub fn library_function(run_msvc_only: bool) {
                 vectorcall_fn_7(S2 { x: 15, y: 16 }, 3);
                 vectorcall_fn_8(S3 { x: [1, 2, 3, 4, 5] }, S3 { x: [6, 7, 8, 9, 10] });
                 vectorcall_fn_9(1, 3.0);
+                vectorcall_fn_10_renamed(19);
             }
         }
     }
diff --git a/src/test/run-make/raw-dylib-alt-calling-convention/output.msvc.txt b/src/test/run-make/raw-dylib-alt-calling-convention/output.msvc.txt
index 9ddd1b110162..a216835c4b62 100644
--- a/src/test/run-make/raw-dylib-alt-calling-convention/output.msvc.txt
+++ b/src/test/run-make/raw-dylib-alt-calling-convention/output.msvc.txt
@@ -9,3 +9,4 @@ vectorcall_fn_6(S { x: 10, y: 12 })
 vectorcall_fn_7(S2 { x: 15, y: 16 }, 3)
 vectorcall_fn_8(S3 { x: [1, 2, 3, 4, 5] }, S3 { x: [6, 7, 8, 9, 10] })
 vectorcall_fn_9(1, 3.0)
+vectorcall_fn_10(19)
diff --git a/src/test/run-make/raw-dylib-alt-calling-convention/output.txt b/src/test/run-make/raw-dylib-alt-calling-convention/output.txt
index 348bad63ed0d..7622d31618b8 100644
--- a/src/test/run-make/raw-dylib-alt-calling-convention/output.txt
+++ b/src/test/run-make/raw-dylib-alt-calling-convention/output.txt
@@ -7,6 +7,7 @@ stdcall_fn_6(S { x: 10, y: 12 })
 stdcall_fn_7(S2 { x: 15, y: 16 }, 3)
 stdcall_fn_8(S3 { x: [1, 2, 3, 4, 5] }, S3 { x: [6, 7, 8, 9, 10] })
 stdcall_fn_9(1, 3.0)
+stdcall_fn_10(19)
 fastcall_fn_1(14)
 fastcall_fn_2(16, 3.5)
 fastcall_fn_3(3.5)
@@ -14,3 +15,4 @@ fastcall_fn_4(1, 2, 3.0)
 fastcall_fn_6(S { x: 10, y: 12 })
 fastcall_fn_8(S3 { x: [1, 2, 3, 4, 5] }, S3 { x: [6, 7, 8, 9, 10] })
 fastcall_fn_9(1, 3.0)
+fastcall_fn_10(19)
diff --git a/src/test/run-make/raw-dylib-c/extern_1.c b/src/test/run-make/raw-dylib-c/extern_1.c
index ab1dc3a4105b..5d695547d0f5 100644
--- a/src/test/run-make/raw-dylib-c/extern_1.c
+++ b/src/test/run-make/raw-dylib-c/extern_1.c
@@ -21,3 +21,8 @@ __declspec(dllexport) void extern_fn_with_long_name() {
     printf("extern_fn_with_long_name; got the rename\n");
     fflush(stdout);
 }
+
+__declspec(dllexport) void extern_fn_4() {
+    printf("extern_fn_4\n");
+    fflush(stdout);
+}
diff --git a/src/test/run-make/raw-dylib-c/lib.rs b/src/test/run-make/raw-dylib-c/lib.rs
index 74e0d3813d94..005ffcdda5c2 100644
--- a/src/test/run-make/raw-dylib-c/lib.rs
+++ b/src/test/run-make/raw-dylib-c/lib.rs
@@ -16,12 +16,15 @@ pub fn library_function() {
         fn extern_fn_2();
         fn print_extern_variable();
         static mut extern_variable: i32;
+        #[link_name = "extern_fn_4"]
+        fn extern_fn_4_renamed();
     }
 
     unsafe {
         extern_fn_1();
         extern_fn_2();
         extern_fn_3();
+        extern_fn_4_renamed();
         extern_variable = 42;
         print_extern_variable();
         extern_variable = -42;
diff --git a/src/test/run-make/raw-dylib-c/output.txt b/src/test/run-make/raw-dylib-c/output.txt
index cd9fe47bee47..cc970cef7bca 100644
--- a/src/test/run-make/raw-dylib-c/output.txt
+++ b/src/test/run-make/raw-dylib-c/output.txt
@@ -1,5 +1,6 @@
 extern_fn_1
 extern_fn_2; didn't get the rename
 extern_fn_3
+extern_fn_4
 extern_variable value: 42
 extern_variable value: -42
diff --git a/src/test/run-make/raw-dylib-import-name-type/driver.rs b/src/test/run-make/raw-dylib-import-name-type/driver.rs
index 74e9a89fbdf3..a38849fc8130 100644
--- a/src/test/run-make/raw-dylib-import-name-type/driver.rs
+++ b/src/test/run-make/raw-dylib-import-name-type/driver.rs
@@ -1,8 +1,11 @@
 #![feature(raw_dylib)]
+#![feature(abi_vectorcall)]
 
 #[link(name = "extern", kind = "raw-dylib", import_name_type = "undecorated")]
 extern "C" {
     fn cdecl_fn_undecorated(i: i32);
+    #[link_name = "cdecl_fn_undecorated2"]
+    fn cdecl_fn_undecorated_renamed(i: i32);
     static mut extern_variable_undecorated: i32;
 }
 
@@ -21,6 +24,8 @@ extern "C" {
 #[link(name = "extern", kind = "raw-dylib", import_name_type = "undecorated")]
 extern "stdcall" {
     fn stdcall_fn_undecorated(i: i32);
+    #[link_name = "stdcall_fn_undecorated2"]
+    fn stdcall_fn_undecorated_renamed(i: i32);
 }
 
 #[link(name = "extern", kind = "raw-dylib", import_name_type = "noprefix")]
@@ -36,6 +41,8 @@ extern "stdcall" {
 #[link(name = "extern", kind = "raw-dylib", import_name_type = "undecorated")]
 extern "fastcall" {
     fn fastcall_fn_undecorated(i: i32);
+    #[link_name = "fastcall_fn_undecorated2"]
+    fn fastcall_fn_undecorated_renamed(i: i32);
 }
 
 #[link(name = "extern", kind = "raw-dylib", import_name_type = "noprefix")]
@@ -48,6 +55,26 @@ extern "fastcall" {
     fn fastcall_fn_decorated(i: i32);
 }
 
+#[cfg(target_env = "msvc")]
+#[link(name = "extern", kind = "raw-dylib", import_name_type = "undecorated")]
+extern "vectorcall" {
+    fn vectorcall_fn_undecorated(i: i32);
+    #[link_name = "vectorcall_fn_undecorated2"]
+    fn vectorcall_fn_undecorated_renamed(i: i32);
+}
+
+#[cfg(target_env = "msvc")]
+#[link(name = "extern", kind = "raw-dylib", import_name_type = "noprefix")]
+extern "vectorcall" {
+    fn vectorcall_fn_noprefix(i: i32);
+}
+
+#[cfg(target_env = "msvc")]
+#[link(name = "extern", kind = "raw-dylib", import_name_type = "decorated")]
+extern "vectorcall" {
+    fn vectorcall_fn_decorated(i: i32);
+}
+
 #[link(name = "extern", kind = "raw-dylib")]
 extern {
     fn print_extern_variable_undecorated();
@@ -58,14 +85,17 @@ extern {
 pub fn main() {
     unsafe {
         cdecl_fn_undecorated(1);
+        cdecl_fn_undecorated_renamed(10);
         cdecl_fn_noprefix(2);
         cdecl_fn_decorated(3);
 
         stdcall_fn_undecorated(4);
+        stdcall_fn_undecorated_renamed(14);
         stdcall_fn_noprefix(5);
         stdcall_fn_decorated(6);
 
         fastcall_fn_undecorated(7);
+        fastcall_fn_undecorated_renamed(17);
         fastcall_fn_noprefix(8);
         fastcall_fn_decorated(9);
 
@@ -75,5 +105,21 @@ pub fn main() {
         print_extern_variable_noprefix();
         extern_variable_decorated = 44;
         print_extern_variable_decorated();
+
+        // GCC doesn't support vectorcall: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89485
+        #[cfg(target_env = "msvc")]
+        {
+            vectorcall_fn_undecorated(10);
+            vectorcall_fn_undecorated_renamed(20);
+            vectorcall_fn_noprefix(11);
+            vectorcall_fn_decorated(12);
+        }
+        #[cfg(not(target_env = "msvc"))]
+        {
+            println!("vectorcall_fn_undecorated(10)");
+            println!("vectorcall_fn_undecorated2(20)");
+            println!("vectorcall_fn_noprefix(11)");
+            println!("vectorcall_fn_decorated(12)");
+        }
     }
 }
diff --git a/src/test/run-make/raw-dylib-import-name-type/extern.c b/src/test/run-make/raw-dylib-import-name-type/extern.c
index 1102158e2494..195126d51294 100644
--- a/src/test/run-make/raw-dylib-import-name-type/extern.c
+++ b/src/test/run-make/raw-dylib-import-name-type/extern.c
@@ -6,6 +6,11 @@ void _cdecl cdecl_fn_undecorated(int i) {
     fflush(stdout);
 }
 
+void _cdecl cdecl_fn_undecorated2(int i) {
+    printf("cdecl_fn_undecorated2(%d)\n", i);
+    fflush(stdout);
+}
+
 void _cdecl cdecl_fn_noprefix(int i) {
     printf("cdecl_fn_noprefix(%d)\n", i);
     fflush(stdout);
@@ -21,6 +26,11 @@ void __stdcall stdcall_fn_undecorated(int i) {
     fflush(stdout);
 }
 
+void __stdcall stdcall_fn_undecorated2(int i) {
+    printf("stdcall_fn_undecorated2(%d)\n", i);
+    fflush(stdout);
+}
+
 void __stdcall stdcall_fn_noprefix(int i) {
     printf("stdcall_fn_noprefix(%d)\n", i);
     fflush(stdout);
@@ -36,6 +46,11 @@ void __fastcall fastcall_fn_undecorated(int i) {
     fflush(stdout);
 }
 
+void __fastcall fastcall_fn_undecorated2(int i) {
+    printf("fastcall_fn_undecorated2(%d)\n", i);
+    fflush(stdout);
+}
+
 void __fastcall fastcall_fn_noprefix(int i) {
     printf("fastcall_fn_noprefix(%d)\n", i);
     fflush(stdout);
@@ -63,3 +78,26 @@ __declspec(dllexport) void print_extern_variable_decorated() {
     printf("extern_variable_decorated value: %d\n", extern_variable_decorated);
     fflush(stdout);
 }
+
+// GCC doesn't support vectorcall: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89485
+#ifdef _MSC_VER
+void __vectorcall vectorcall_fn_undecorated(int i) {
+    printf("vectorcall_fn_undecorated(%d)\n", i);
+    fflush(stdout);
+}
+
+void __vectorcall vectorcall_fn_undecorated2(int i) {
+    printf("vectorcall_fn_undecorated2(%d)\n", i);
+    fflush(stdout);
+}
+
+void __vectorcall vectorcall_fn_noprefix(int i) {
+    printf("vectorcall_fn_noprefix(%d)\n", i);
+    fflush(stdout);
+}
+
+void __vectorcall vectorcall_fn_decorated(int i) {
+    printf("vectorcall_fn_decorated(%d)\n", i);
+    fflush(stdout);
+}
+#endif
diff --git a/src/test/run-make/raw-dylib-import-name-type/extern.gnu.def b/src/test/run-make/raw-dylib-import-name-type/extern.gnu.def
index f06ce67e0308..a523c959a474 100644
--- a/src/test/run-make/raw-dylib-import-name-type/extern.gnu.def
+++ b/src/test/run-make/raw-dylib-import-name-type/extern.gnu.def
@@ -1,11 +1,14 @@
 LIBRARY extern
 EXPORTS
     cdecl_fn_undecorated
+    cdecl_fn_undecorated2
     cdecl_fn_noprefix
     cdecl_fn_decorated
     stdcall_fn_undecorated
+    stdcall_fn_undecorated2
     stdcall_fn_noprefix@4
     fastcall_fn_undecorated
+    fastcall_fn_undecorated2
     @fastcall_fn_decorated@4
 
     ;ld doesn't handle fully-decorated stdcall, or no-prefix fastcall
diff --git a/src/test/run-make/raw-dylib-import-name-type/extern.msvc.def b/src/test/run-make/raw-dylib-import-name-type/extern.msvc.def
index 9dc333707cb0..dbff32d4c90b 100644
--- a/src/test/run-make/raw-dylib-import-name-type/extern.msvc.def
+++ b/src/test/run-make/raw-dylib-import-name-type/extern.msvc.def
@@ -1,12 +1,19 @@
 LIBRARY extern
 EXPORTS
     cdecl_fn_undecorated
+    cdecl_fn_undecorated2
     cdecl_fn_noprefix
     cdecl_fn_decorated
     stdcall_fn_undecorated
+    stdcall_fn_undecorated2
     _stdcall_fn_decorated@4
     fastcall_fn_undecorated
+    fastcall_fn_undecorated2
     @fastcall_fn_decorated@4
+    vectorcall_fn_undecorated
+    vectorcall_fn_undecorated2
+    vectorcall_fn_decorated@@4
+    vectorcall_fn_noprefix@@4
 
     ;MSVC doesn't seem to recognize the "no prefix" syntax.
     stdcall_fn_noprefix@4=_stdcall_fn_noprefix@4
diff --git a/src/test/run-make/raw-dylib-import-name-type/output.txt b/src/test/run-make/raw-dylib-import-name-type/output.txt
index 855b20a86457..707faf403aec 100644
--- a/src/test/run-make/raw-dylib-import-name-type/output.txt
+++ b/src/test/run-make/raw-dylib-import-name-type/output.txt
@@ -1,12 +1,19 @@
 cdecl_fn_undecorated(1)
+cdecl_fn_undecorated2(10)
 cdecl_fn_noprefix(2)
 cdecl_fn_decorated(3)
 stdcall_fn_undecorated(4)
+stdcall_fn_undecorated2(14)
 stdcall_fn_noprefix(5)
 stdcall_fn_decorated(6)
 fastcall_fn_undecorated(7)
+fastcall_fn_undecorated2(17)
 fastcall_fn_noprefix(8)
 fastcall_fn_decorated(9)
 extern_variable_undecorated value: 42
 extern_variable_noprefix value: 43
 extern_variable_decorated value: 44
+vectorcall_fn_undecorated(10)
+vectorcall_fn_undecorated2(20)
+vectorcall_fn_noprefix(11)
+vectorcall_fn_decorated(12)
diff --git a/src/test/run-make/raw-dylib-link-ordinal/lib.rs b/src/test/run-make/raw-dylib-link-ordinal/lib.rs
index 5efce4e938c8..bb25ac64c613 100644
--- a/src/test/run-make/raw-dylib-link-ordinal/lib.rs
+++ b/src/test/run-make/raw-dylib-link-ordinal/lib.rs
@@ -1,4 +1,4 @@
-#![feature(raw_dylib)]
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "exporter", kind = "raw-dylib")]
 extern {
diff --git a/src/test/run-make/raw-dylib-stdcall-ordinal/lib.rs b/src/test/run-make/raw-dylib-stdcall-ordinal/lib.rs
index 07dd3d7be9b9..b7921396a0f4 100644
--- a/src/test/run-make/raw-dylib-stdcall-ordinal/lib.rs
+++ b/src/test/run-make/raw-dylib-stdcall-ordinal/lib.rs
@@ -1,4 +1,4 @@
-#![feature(raw_dylib)]
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "exporter", kind = "raw-dylib")]
 extern "stdcall" {
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs-2/Makefile b/src/test/run-make/rlib-format-packed-bundled-libs-2/Makefile
new file mode 100644
index 000000000000..4574cf17f0ef
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs-2/Makefile
@@ -0,0 +1,22 @@
+-include ../../run-make-fulldeps/tools.mk
+
+# ignore-cross-compile
+
+# Make sure -Zpacked_bundled_libs is compatible with verbatim.
+
+# We're using the llvm-nm instead of the system nm to ensure it is compatible
+# with the LLVM bitcode generated by rustc.
+NM = "$(LLVM_BIN_DIR)"/llvm-nm
+
+all:
+	# Build strange-named dep.
+	$(RUSTC) native_dep.rs --crate-type=staticlib -o $(TMPDIR)/native_dep.ext
+
+	$(RUSTC) rust_dep.rs --crate-type=rlib -Zpacked_bundled_libs
+	$(NM) $(TMPDIR)/librust_dep.rlib | $(CGREP) -e "U.*native_f1"
+	$(AR) t $(TMPDIR)/librust_dep.rlib | $(CGREP) "native_dep.ext"
+
+	# Make sure compiler doesn't use files, that it shouldn't know about.
+	rm $(TMPDIR)/native_dep.ext
+
+	$(RUSTC) main.rs --extern rust_dep=$(TMPDIR)/librust_dep.rlib -Zpacked_bundled_libs
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs-2/main.rs b/src/test/run-make/rlib-format-packed-bundled-libs-2/main.rs
new file mode 100644
index 000000000000..8d2b8a2859c0
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs-2/main.rs
@@ -0,0 +1,5 @@
+extern crate rust_dep;
+
+pub fn main() {
+    rust_dep::rust_dep();
+}
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs-2/native_dep.rs b/src/test/run-make/rlib-format-packed-bundled-libs-2/native_dep.rs
new file mode 100644
index 000000000000..321a8237e8a4
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs-2/native_dep.rs
@@ -0,0 +1,4 @@
+#[no_mangle]
+pub fn native_f1() -> i32 {
+    return 1;
+}
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs-2/rust_dep.rs b/src/test/run-make/rlib-format-packed-bundled-libs-2/rust_dep.rs
new file mode 100644
index 000000000000..d99dda05cf21
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs-2/rust_dep.rs
@@ -0,0 +1,11 @@
+#![feature(native_link_modifiers_verbatim)]
+#[link(name = "native_dep.ext", kind = "static", modifiers = "+verbatim")]
+extern "C" {
+    fn native_f1() -> i32;
+}
+
+pub fn rust_dep() {
+    unsafe {
+        assert!(native_f1() == 1);
+    }
+}
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/Makefile b/src/test/run-make/rlib-format-packed-bundled-libs/Makefile
new file mode 100644
index 000000000000..0b991ac42e3d
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/Makefile
@@ -0,0 +1,34 @@
+-include ../../run-make-fulldeps/tools.mk
+
+# ignore-cross-compile
+
+# Make sure rlib format with -Zpacked_bundled_libs is correct.
+
+# We're using the llvm-nm instead of the system nm to ensure it is compatible
+# with the LLVM bitcode generated by rustc.
+NM = "$(LLVM_BIN_DIR)"/llvm-nm
+
+all: $(call NATIVE_STATICLIB,native_dep_1) $(call NATIVE_STATICLIB,native_dep_2) $(call NATIVE_STATICLIB,native_dep_3)
+	$(RUSTC) rust_dep_up.rs --crate-type=rlib -Zpacked_bundled_libs
+	$(NM) $(TMPDIR)/librust_dep_up.rlib | $(CGREP) -e "U.*native_f2"
+	$(NM) $(TMPDIR)/librust_dep_up.rlib | $(CGREP) -e "U.*native_f3"
+	$(NM) $(TMPDIR)/librust_dep_up.rlib | $(CGREP) -e "T.*rust_dep_up"
+	$(AR) t $(TMPDIR)/librust_dep_up.rlib | $(CGREP) "native_dep_2"
+	$(AR) t $(TMPDIR)/librust_dep_up.rlib | $(CGREP) "native_dep_3"
+	$(RUSTC) rust_dep_local.rs --extern rlib=$(TMPDIR)/librust_dep_up.rlib -Zpacked_bundled_libs --crate-type=rlib
+	$(NM) $(TMPDIR)/librust_dep_local.rlib | $(CGREP) -e "U.*native_f1"
+	$(NM) $(TMPDIR)/librust_dep_local.rlib | $(CGREP) -e "T.*rust_dep_local"
+	$(AR) t $(TMPDIR)/librust_dep_local.rlib | $(CGREP) "native_dep_1"
+
+	# Make sure compiler doesn't use files, that it shouldn't know about.
+	rm $(TMPDIR)/*native_dep_*
+
+	$(RUSTC) main.rs --extern lib=$(TMPDIR)/librust_dep_local.rlib -o $(TMPDIR)/main.exe -Zpacked_bundled_libs --print link-args | $(CGREP) -e "native_dep_1.*native_dep_2.*native_dep_3"
+
+ifndef IS_MSVC
+	$(NM) $(TMPDIR)/main.exe | $(CGREP) -e "T.*native_f1"
+	$(NM) $(TMPDIR)/main.exe | $(CGREP) -e "T.*native_f2"
+	$(NM) $(TMPDIR)/main.exe | $(CGREP) -e "T.*native_f3"
+	$(NM) $(TMPDIR)/main.exe | $(CGREP) -e "T.*rust_dep_local"
+	$(NM) $(TMPDIR)/main.exe | $(CGREP) -e "T.*rust_dep_up"
+endif
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/main.rs b/src/test/run-make/rlib-format-packed-bundled-libs/main.rs
new file mode 100644
index 000000000000..042a4879fe4e
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/main.rs
@@ -0,0 +1,4 @@
+extern crate rust_dep_local;
+pub fn main() {
+    rust_dep_local::rust_dep_local();
+}
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_1.c b/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_1.c
new file mode 100644
index 000000000000..07be8562c928
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_1.c
@@ -0,0 +1 @@
+int native_f1() { return 1; }
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_2.c b/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_2.c
new file mode 100644
index 000000000000..a1b94e40dc04
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_2.c
@@ -0,0 +1 @@
+int native_f2() { return 2; }
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_3.c b/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_3.c
new file mode 100644
index 000000000000..f81f397a4b1d
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/native_dep_3.c
@@ -0,0 +1 @@
+int native_f3() { return 3; }
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/rust_dep_local.rs b/src/test/run-make/rlib-format-packed-bundled-libs/rust_dep_local.rs
new file mode 100644
index 000000000000..8280c7d6c515
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/rust_dep_local.rs
@@ -0,0 +1,13 @@
+#[link(name = "native_dep_1", kind = "static")]
+extern "C" {
+    fn native_f1() -> i32;
+}
+
+extern crate rust_dep_up;
+
+pub fn rust_dep_local() {
+    unsafe {
+        assert!(native_f1() == 1);
+    }
+    rust_dep_up::rust_dep_up();
+}
diff --git a/src/test/run-make/rlib-format-packed-bundled-libs/rust_dep_up.rs b/src/test/run-make/rlib-format-packed-bundled-libs/rust_dep_up.rs
new file mode 100644
index 000000000000..edcd7c521298
--- /dev/null
+++ b/src/test/run-make/rlib-format-packed-bundled-libs/rust_dep_up.rs
@@ -0,0 +1,13 @@
+#[link(name = "native_dep_2", kind = "static")]
+#[link(name = "native_dep_3", kind = "static")]
+extern "C" {
+    fn native_f2() -> i32;
+    fn native_f3() -> i32;
+}
+
+pub fn rust_dep_up() {
+    unsafe {
+        assert!(native_f2() == 2);
+        assert!(native_f3() == 3);
+    }
+}
diff --git a/src/test/run-make/track-pgo-dep-info/Makefile b/src/test/run-make/track-pgo-dep-info/Makefile
new file mode 100644
index 000000000000..60b59c04aa95
--- /dev/null
+++ b/src/test/run-make/track-pgo-dep-info/Makefile
@@ -0,0 +1,26 @@
+# needs-profiler-support
+# ignore-windows-gnu
+
+-include ../../run-make-fulldeps/tools.mk
+
+# FIXME(eddyb) provide `HOST_RUSTC` and `TARGET_RUSTC`
+# instead of hardcoding them everywhere they're needed.
+ifeq ($(IS_MUSL_HOST),1)
+ADDITIONAL_ARGS := $(RUSTFLAGS)
+endif
+
+all:
+	# Generate PGO profiles
+	$(BARE_RUSTC) $(ADDITIONAL_ARGS) -Cprofile-generate=$(TMPDIR)/profiles --out-dir $(TMPDIR) main.rs
+	$(TMPDIR)/main
+
+	# Merge profiles
+	"$(LLVM_BIN_DIR)/llvm-profdata" merge \
+		-o "$(TMPDIR)/merged.profdata" \
+		"$(TMPDIR)/profiles" || exit 1
+
+	# Use the profile
+	$(RUSTC) -Cprofile-use=$(TMPDIR)/merged.profdata --emit dep-info main.rs
+
+	# Check that profile file is in depinfo
+	$(CGREP) "merged.profdata" < $(TMPDIR)/main.d
diff --git a/src/test/run-make/track-pgo-dep-info/main.rs b/src/test/run-make/track-pgo-dep-info/main.rs
new file mode 100644
index 000000000000..f328e4d9d04c
--- /dev/null
+++ b/src/test/run-make/track-pgo-dep-info/main.rs
@@ -0,0 +1 @@
+fn main() {}
diff --git a/src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh b/src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh
index 54645e9e257c..944343df6e58 100644
--- a/src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh
+++ b/src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh
@@ -45,7 +45,7 @@ check cc_plus_one_cxx cc_plus_one_cxx.checks
 check cc_plus_one_cxx_asm cc_plus_one_cxx_asm.checks
 check cc_plus_one_asm cc_plus_one_asm.checks \
   || echo "warning: the cc crate forwards assembly files to the CC compiler." \
-           "Clang uses its own intergrated assembler, which does not include the LVI passes."
+           "Clang uses its own integrated assembler, which does not include the LVI passes."
 
 check cmake_plus_one_c cmake_plus_one_c.checks
 check cmake_plus_one_c_asm cmake_plus_one_c_asm.checks
diff --git a/src/test/rustdoc-gui/check-code-blocks-margin.goml b/src/test/rustdoc-gui/check-code-blocks-margin.goml
index f6266eba75de..f2fc3e9afc2a 100644
--- a/src/test/rustdoc-gui/check-code-blocks-margin.goml
+++ b/src/test/rustdoc-gui/check-code-blocks-margin.goml
@@ -1,6 +1,6 @@
 // This test ensures that the docblock elements have the appropriate left margin.
 goto: file://|DOC_PATH|/test_docs/fn.foo.html
 // The top docblock elements shouldn't have left margin...
-assert-css: ("#main-content .docblock.item-decl", {"margin-left": "0px"})
+assert-css: ("#main-content .item-decl", {"margin-left": "0px"})
 // ... but all the others should!
-assert-css: ("#main-content .docblock:not(.item-decl)", {"margin-left": "24px"})
+assert-css: ("#main-content .docblock", {"margin-left": "24px"})
diff --git a/src/test/rustdoc-gui/check-stab-in-docblock.goml b/src/test/rustdoc-gui/check-stab-in-docblock.goml
new file mode 100644
index 000000000000..afe25195100c
--- /dev/null
+++ b/src/test/rustdoc-gui/check-stab-in-docblock.goml
@@ -0,0 +1,27 @@
+// This test checks that using `.stab` attributes in `.docblock` elements doesn't
+// create scrollable paragraphs.
+goto: file://|DOC_PATH|/test_docs/index.html
+// Needs the text to be display to check for scrollable content.
+show-text: true
+size: (786, 600)
+// Confirms that there 3 paragraphs.
+assert-count: (".top-doc .docblock p", 3)
+// Checking that there is no scrollable content.
+store-property: (clientHeight, ".top-doc .docblock p:nth-of-type(1)", "clientHeight")
+store-property: (clientWidth, ".top-doc .docblock p:nth-of-type(1)", "clientWidth")
+assert-property: (
+    ".top-doc .docblock p:nth-of-type(1)",
+    {"scrollHeight": |clientHeight|, "scrollWidth": |clientWidth|},
+)
+store-property: (clientHeight, ".top-doc .docblock p:nth-of-type(2)", "clientHeight")
+store-property: (clientWidth, ".top-doc .docblock p:nth-of-type(2)", "clientWidth")
+assert-property: (
+    ".top-doc .docblock p:nth-of-type(2)",
+    {"scrollHeight": |clientHeight|, "scrollWidth": |clientWidth|},
+)
+store-property: (clientHeight, ".top-doc .docblock p:nth-of-type(3)", "clientHeight")
+store-property: (clientWidth, ".top-doc .docblock p:nth-of-type(3)", "clientWidth")
+assert-property: (
+    ".top-doc .docblock p:nth-of-type(3)",
+    {"scrollHeight": |clientHeight|, "scrollWidth": |clientWidth|},
+)
diff --git a/src/test/rustdoc-gui/check_info_sign_position.goml b/src/test/rustdoc-gui/check_info_sign_position.goml
index 3bed7a0a03ea..47a78f02fb67 100644
--- a/src/test/rustdoc-gui/check_info_sign_position.goml
+++ b/src/test/rustdoc-gui/check_info_sign_position.goml
@@ -4,8 +4,8 @@ goto: file://|DOC_PATH|/test_docs/index.html
 goto: ./fn.check_list_code_block.html
 // If the codeblock is the first element of the docblock, the information tooltip must have
 // have some top margin to avoid going over the toggle (the "[+]").
-assert-css: (".docblock > .information > .compile_fail", { "margin-top": "16px" })
+assert-css: (".docblock > .example-wrap.compile_fail .tooltip", { "margin-top": "16px" })
 // Checks that the other codeblocks don't have this top margin.
-assert-css: ("ol > li > .information > .compile_fail", { "margin-top": "0px" })
-assert-css: ("ol > li > .information > .ignore", { "margin-top": "0px" })
-assert-css: (".docblock > .information > .ignore", { "margin-top": "0px" })
+assert-css: ("ol > li > .example-wrap.compile_fail .tooltip", { "margin-top": "0px" })
+assert-css: ("ol > li > .example-wrap.ignore .tooltip", { "margin-top": "0px" })
+assert-css: (".docblock > .example-wrap.ignore .tooltip", { "margin-top": "0px" })
diff --git a/src/test/rustdoc-gui/code-blocks-overflow.goml b/src/test/rustdoc-gui/code-blocks-overflow.goml
index f93f3f0aefc5..ee4dad444e93 100644
--- a/src/test/rustdoc-gui/code-blocks-overflow.goml
+++ b/src/test/rustdoc-gui/code-blocks-overflow.goml
@@ -5,4 +5,4 @@ size: (1080, 600)
 assert-count: (".docblock > .example-wrap", 2)
 assert: ".docblock > .example-wrap > .language-txt"
 assert: ".docblock > .example-wrap > .rust-example-rendered"
-assert-css: (".docblock > .example-wrap > pre", {"width": "785.25px", "overflow-x": "auto"}, ALL)
+assert-css: (".docblock > .example-wrap > pre", {"width": "796px", "overflow-x": "auto"}, ALL)
diff --git a/src/test/rustdoc-gui/code-tags.goml b/src/test/rustdoc-gui/code-tags.goml
index 200569a28d4a..8d399a9a5897 100644
--- a/src/test/rustdoc-gui/code-tags.goml
+++ b/src/test/rustdoc-gui/code-tags.goml
@@ -1,9 +1,9 @@
 // This test ensures that items and documentation code blocks are wrapped in <pre><code>
 goto: file://|DOC_PATH|/test_docs/fn.foo.html
 size: (1080, 600)
-// There should be three doc codeblocks
+// There should be four doc codeblocks.
 // Check that their content is inside <pre><code>
-assert-count: (".example-wrap pre > code", 3)
+assert-count: (".example-wrap pre > code", 4)
 // Check that function signature is inside <pre><code>
 assert: "pre.rust.fn > code"
 
diff --git a/src/test/rustdoc-gui/codeblock-tooltip.goml b/src/test/rustdoc-gui/codeblock-tooltip.goml
new file mode 100644
index 000000000000..21a9e120c80a
--- /dev/null
+++ b/src/test/rustdoc-gui/codeblock-tooltip.goml
@@ -0,0 +1,96 @@
+// Checking the colors of the codeblocks tooltips.
+goto: file://|DOC_PATH|/test_docs/fn.foo.html
+show-text: true
+
+// Dark theme.
+local-storage: {"rustdoc-theme": "dark", "rustdoc-use-system-theme": "false"}
+reload:
+
+// compile_fail block
+assert-css: (".docblock .example-wrap.compile_fail .tooltip", {"color": "rgba(255, 0, 0, 0.5)"})
+assert-css: (".docblock .example-wrap.compile_fail", {"border-left": "2px solid rgba(255, 0, 0, 0.5)"})
+
+move-cursor-to: ".docblock .example-wrap.compile_fail"
+
+assert-css: (".docblock .example-wrap.compile_fail .tooltip", {"color": "rgb(255, 0, 0)"})
+assert-css: (".docblock .example-wrap.compile_fail", {"border-left": "2px solid rgb(255, 0, 0)"})
+
+// should_panic block
+assert-css: (".docblock .example-wrap.should_panic .tooltip", {"color": "rgba(255, 0, 0, 0.5)"})
+assert-css: (".docblock .example-wrap.should_panic", {"border-left": "2px solid rgba(255, 0, 0, 0.5)"})
+
+move-cursor-to: ".docblock .example-wrap.should_panic"
+
+assert-css: (".docblock .example-wrap.should_panic .tooltip", {"color": "rgb(255, 0, 0)"})
+assert-css: (".docblock .example-wrap.should_panic", {"border-left": "2px solid rgb(255, 0, 0)"})
+
+// ignore block
+assert-css: (".docblock .example-wrap.ignore .tooltip", {"color": "rgba(255, 142, 0, 0.6)"})
+assert-css: (".docblock .example-wrap.ignore", {"border-left": "2px solid rgba(255, 142, 0, 0.6)"})
+
+move-cursor-to: ".docblock .example-wrap.ignore"
+
+assert-css: (".docblock .example-wrap.ignore .tooltip", {"color": "rgb(255, 142, 0)"})
+assert-css: (".docblock .example-wrap.ignore", {"border-left": "2px solid rgb(255, 142, 0)"})
+
+
+// Light theme.
+local-storage: {"rustdoc-theme": "light"}
+reload:
+
+assert-css: (".docblock .example-wrap.compile_fail .tooltip", {"color": "rgba(255, 0, 0, 0.5)"})
+assert-css: (".docblock .example-wrap.compile_fail", {"border-left": "2px solid rgba(255, 0, 0, 0.5)"})
+
+move-cursor-to: ".docblock .example-wrap.compile_fail"
+
+assert-css: (".docblock .example-wrap.compile_fail .tooltip", {"color": "rgb(255, 0, 0)"})
+assert-css: (".docblock .example-wrap.compile_fail", {"border-left": "2px solid rgb(255, 0, 0)"})
+
+// should_panic block
+assert-css: (".docblock .example-wrap.should_panic .tooltip", {"color": "rgba(255, 0, 0, 0.5)"})
+assert-css: (".docblock .example-wrap.should_panic", {"border-left": "2px solid rgba(255, 0, 0, 0.5)"})
+
+move-cursor-to: ".docblock .example-wrap.should_panic"
+
+assert-css: (".docblock .example-wrap.should_panic .tooltip", {"color": "rgb(255, 0, 0)"})
+assert-css: (".docblock .example-wrap.should_panic", {"border-left": "2px solid rgb(255, 0, 0)"})
+
+// ignore block
+assert-css: (".docblock .example-wrap.ignore .tooltip", {"color": "rgba(255, 142, 0, 0.6)"})
+assert-css: (".docblock .example-wrap.ignore", {"border-left": "2px solid rgba(255, 142, 0, 0.6)"})
+
+move-cursor-to: ".docblock .example-wrap.ignore"
+
+assert-css: (".docblock .example-wrap.ignore .tooltip", {"color": "rgb(255, 142, 0)"})
+assert-css: (".docblock .example-wrap.ignore", {"border-left": "2px solid rgb(255, 142, 0)"})
+
+
+// Ayu theme.
+local-storage: {"rustdoc-theme": "ayu"}
+reload:
+
+assert-css: (".docblock .example-wrap.compile_fail .tooltip", {"color": "rgba(255, 0, 0, 0.5)"})
+assert-css: (".docblock .example-wrap.compile_fail", {"border-left": "2px solid rgba(255, 0, 0, 0.5)"})
+
+move-cursor-to: ".docblock .example-wrap.compile_fail"
+
+assert-css: (".docblock .example-wrap.compile_fail .tooltip", {"color": "rgb(255, 0, 0)"})
+assert-css: (".docblock .example-wrap.compile_fail", {"border-left": "2px solid rgb(255, 0, 0)"})
+
+// should_panic block
+assert-css: (".docblock .example-wrap.should_panic .tooltip", {"color": "rgba(255, 0, 0, 0.5)"})
+assert-css: (".docblock .example-wrap.should_panic", {"border-left": "2px solid rgba(255, 0, 0, 0.5)"})
+
+move-cursor-to: ".docblock .example-wrap.should_panic"
+
+assert-css: (".docblock .example-wrap.should_panic .tooltip", {"color": "rgb(255, 0, 0)"})
+assert-css: (".docblock .example-wrap.should_panic", {"border-left": "2px solid rgb(255, 0, 0)"})
+
+// ignore block
+assert-css: (".docblock .example-wrap.ignore .tooltip", {"color": "rgba(255, 142, 0, 0.6)"})
+assert-css: (".docblock .example-wrap.ignore", {"border-left": "2px solid rgba(255, 142, 0, 0.6)"})
+
+move-cursor-to: ".docblock .example-wrap.ignore"
+
+assert-css: (".docblock .example-wrap.ignore .tooltip", {"color": "rgb(255, 142, 0)"})
+assert-css: (".docblock .example-wrap.ignore", {"border-left": "2px solid rgb(255, 142, 0)"})
diff --git a/src/test/rustdoc-gui/docblock-code-block-line-number.goml b/src/test/rustdoc-gui/docblock-code-block-line-number.goml
index baf9651c40de..ebfffbce7156 100644
--- a/src/test/rustdoc-gui/docblock-code-block-line-number.goml
+++ b/src/test/rustdoc-gui/docblock-code-block-line-number.goml
@@ -20,3 +20,20 @@ assert-css: ("pre.line-number", {
 })
 // The first code block has two lines so let's check its `<pre>` elements lists both of them.
 assert-text: ("pre.line-number", "1\n2")
+
+// Now, try changing the setting dynamically. We'll turn it off, using the settings menu,
+// and make sure it goes away.
+
+// First, open the settings menu.
+click: "#settings-menu"
+wait-for: "#settings"
+assert-css: ("#settings", {"display": "block"})
+
+// Then, click the toggle button.
+click: "input#line-numbers + .slider"
+wait-for: 100 // wait-for-false does not exist
+assert-false: "pre.line-number"
+
+// Finally, turn it on again.
+click: "input#line-numbers + .slider"
+wait-for: "pre.line-number"
diff --git a/src/test/rustdoc-gui/docblock-details.goml b/src/test/rustdoc-gui/docblock-details.goml
index f6287ade2f29..c0c4d1b43aac 100644
--- a/src/test/rustdoc-gui/docblock-details.goml
+++ b/src/test/rustdoc-gui/docblock-details.goml
@@ -14,7 +14,7 @@ assert-css: (
 // We now check that the `<summary>` doesn't have a bottom border and has the correct display.
 assert-css: (
     ".top-doc .docblock summary h4",
-    {"border-bottom": "0px none rgb(210, 210, 210)"},
+    {"border-bottom-width": "0px"},
 )
 // This allows to ensure that summary is on one line only!
 assert-property: (".top-doc .docblock summary h4", {"offsetHeight": "33"})
diff --git a/src/test/rustdoc-gui/docblock-table-overflow.goml b/src/test/rustdoc-gui/docblock-table-overflow.goml
index af76d2ea4276..ef0d37c902e0 100644
--- a/src/test/rustdoc-gui/docblock-table-overflow.goml
+++ b/src/test/rustdoc-gui/docblock-table-overflow.goml
@@ -4,9 +4,9 @@ goto: file://|DOC_PATH|/lib2/long_table/struct.Foo.html
 size: (1100, 800)
 // Logically, the ".docblock" and the "<p>" should have the same scroll width.
 compare-elements-property: (".top-doc .docblock", ".top-doc .docblock > p", ["scrollWidth"])
-assert-property: (".top-doc .docblock", {"scrollWidth": "801"})
+assert-property: (".top-doc .docblock", {"scrollWidth": "816"})
 // However, since there is overflow in the <table>, its scroll width is bigger.
-assert-property: (".top-doc .docblock table", {"scrollWidth": "1573"})
+assert-property: (".top-doc .docblock table", {"scrollWidth": "1572"})
 
 // Checking it works on other doc blocks as well...
 
@@ -16,6 +16,6 @@ compare-elements-property: (
     "#implementations-list > details .docblock > p",
     ["scrollWidth"],
 )
-assert-property: ("#implementations-list > details .docblock", {"scrollWidth": "801"})
+assert-property: ("#implementations-list > details .docblock", {"scrollWidth": "816"})
 // However, since there is overflow in the <table>, its scroll width is bigger.
-assert-property: ("#implementations-list > details .docblock table", {"scrollWidth": "1573"})
+assert-property: ("#implementations-list > details .docblock table", {"scrollWidth": "1572"})
diff --git a/src/test/rustdoc-gui/font-weight.goml b/src/test/rustdoc-gui/font-weight.goml
index 5f29fde6689b..13e8ec9fb16a 100644
--- a/src/test/rustdoc-gui/font-weight.goml
+++ b/src/test/rustdoc-gui/font-weight.goml
@@ -1,6 +1,6 @@
 // This test checks that the font weight is correctly applied.
 goto: file://|DOC_PATH|/lib2/struct.Foo.html
-assert-css: ("//*[@class='docblock item-decl']//a[text()='Alias']", {"font-weight": "400"})
+assert-css: ("//*[@class='item-decl']//a[text()='Alias']", {"font-weight": "400"})
 assert-css: (
     "//*[@class='structfield small-section-header']//a[text()='Alias']",
     {"font-weight": "400"},
@@ -19,7 +19,7 @@ goto: file://|DOC_PATH|/lib2/trait.Trait.html
 
 // This is a complex selector, so here's how it works:
 //
-// * //*[@class='docblock item-decl'] — selects element of any tag with classes docblock and item-decl
+// * //*[@class='item-decl'] — selects element of any tag with classes docblock and item-decl
 // * /pre[@class='rust trait'] — selects immediate child with tag pre and classes rust and trait
 // * /code — selects immediate child with tag code
 // * /a[@class='constant'] — selects immediate child with tag a and class constant
@@ -29,11 +29,11 @@ goto: file://|DOC_PATH|/lib2/trait.Trait.html
 // This uses '/parent::*' as a proxy for the style of the text node.
 // We can't just select the '<a>' because intermediate tags could be added.
 assert-count: (
-    "//*[@class='docblock item-decl']/pre[@class='rust trait']/code/a[@class='constant']//text()/parent::*",
+    "//*[@class='item-decl']/pre[@class='rust trait']/code/a[@class='constant']//text()/parent::*",
     1,
 )
 assert-css: (
-    "//*[@class='docblock item-decl']/pre[@class='rust trait']/code/a[@class='constant']//text()/parent::*",
+    "//*[@class='item-decl']/pre[@class='rust trait']/code/a[@class='constant']//text()/parent::*",
     {"font-weight": "400"},
 )
 
diff --git a/src/test/rustdoc-gui/headers-color.goml b/src/test/rustdoc-gui/headers-color.goml
index a47a9c8a14c1..4f01f1a16245 100644
--- a/src/test/rustdoc-gui/headers-color.goml
+++ b/src/test/rustdoc-gui/headers-color.goml
@@ -19,7 +19,7 @@ assert-css: (
 )
 assert-css: (
     ".impl .code-header",
-    {"color": "rgb(230, 225, 207)", "background-color": "rgb(15, 20, 25)"},
+    {"color": "rgb(230, 225, 207)", "background-color": "rgba(0, 0, 0, 0)"},
     ALL,
 )
 
@@ -58,7 +58,7 @@ assert-css: (
 )
 assert-css: (
     ".impl .code-header",
-    {"color": "rgb(221, 221, 221)", "background-color": "rgb(53, 53, 53)"},
+    {"color": "rgb(221, 221, 221)", "background-color": "rgba(0, 0, 0, 0)"},
     ALL,
 )
 
@@ -95,7 +95,7 @@ assert-css: (
 )
 assert-css: (
     ".impl .code-header",
-    {"color": "rgb(0, 0, 0)", "background-color": "rgb(255, 255, 255)"},
+    {"color": "rgb(0, 0, 0)", "background-color": "rgba(0, 0, 0, 0)"},
     ALL,
 )
 
diff --git a/src/test/rustdoc-gui/headings.goml b/src/test/rustdoc-gui/headings.goml
index ed07e777b188..53308e13480b 100644
--- a/src/test/rustdoc-gui/headings.goml
+++ b/src/test/rustdoc-gui/headings.goml
@@ -168,19 +168,19 @@ assert-css: (
 )
 assert-css: (
     ".top-doc .docblock h5",
-    {"color": "rgb(0, 0, 0)", "border-bottom": "0px none rgb(221, 221, 221)"},
+    {"color": "rgb(0, 0, 0)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h4",
-    {"color": "rgb(0, 0, 0)", "border-bottom": "0px none rgb(221, 221, 221)"},
+    {"color": "rgb(0, 0, 0)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h5",
-    {"color": "rgb(0, 0, 0)", "border-bottom": "0px none rgb(221, 221, 221)"},
+    {"color": "rgb(0, 0, 0)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h6",
-    {"color": "rgb(0, 0, 0)", "border-bottom": "0px none rgb(221, 221, 221)"},
+    {"color": "rgb(0, 0, 0)", "border-bottom-width": "0px"},
 )
 
 local-storage: {"rustdoc-theme": "dark"}
@@ -199,19 +199,19 @@ assert-css: (
 )
 assert-css: (
     ".top-doc .docblock h5",
-    {"color": "rgb(221, 221, 221)", "border-bottom": "0px none rgb(210, 210, 210)"},
+    {"color": "rgb(221, 221, 221)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h4",
-    {"color": "rgb(221, 221, 221)", "border-bottom": "0px none rgb(210, 210, 210)"},
+    {"color": "rgb(221, 221, 221)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h5",
-    {"color": "rgb(221, 221, 221)", "border-bottom": "0px none rgb(210, 210, 210)"},
+    {"color": "rgb(221, 221, 221)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h6",
-    {"color": "rgb(221, 221, 221)", "border-bottom": "0px none rgb(210, 210, 210)"},
+    {"color": "rgb(221, 221, 221)", "border-bottom-width": "0px"},
 )
 
 local-storage: {"rustdoc-theme": "ayu"}
@@ -230,19 +230,19 @@ assert-css: (
 )
 assert-css: (
     ".top-doc .docblock h5",
-    {"color": "rgb(197, 197, 197)", "border-bottom": "0px none rgb(92, 103, 115)"},
+    {"color": "rgb(197, 197, 197)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h4",
-    {"color": "rgb(255, 255, 255)", "border-bottom": "0px none rgb(92, 103, 115)"},
+    {"color": "rgb(255, 255, 255)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h5",
-    {"color": "rgb(197, 197, 197)", "border-bottom": "0px none rgb(92, 103, 115)"},
+    {"color": "rgb(197, 197, 197)", "border-bottom-width": "0px"},
 )
 assert-css: (
     "#implementations-list .docblock h6",
-    {"color": "rgb(197, 197, 197)", "border-bottom": "0px none rgb(92, 103, 115)"},
+    {"color": "rgb(197, 197, 197)", "border-bottom-width": "0px"},
 )
 
 local-storage: {"rustdoc-theme": "light"}
diff --git a/src/test/rustdoc-gui/implementors.goml b/src/test/rustdoc-gui/implementors.goml
index 666a6e1253d9..2fcbee27147e 100644
--- a/src/test/rustdoc-gui/implementors.goml
+++ b/src/test/rustdoc-gui/implementors.goml
@@ -8,23 +8,23 @@ assert-count: ("#implementors-list .impl", 2)
 assert: ("#implementors-list .impl:nth-child(1) > a.anchor")
 assert-attribute: ("#implementors-list .impl:nth-child(1)", {"id": "impl-Whatever-for-Struct"})
 assert-attribute: ("#implementors-list .impl:nth-child(1) > a.anchor", {"href": "#impl-Whatever-for-Struct"})
-assert: "#implementors-list .impl:nth-child(1) > .code-header.in-band"
+assert: "#implementors-list .impl:nth-child(1) > .code-header"
 
 assert: ("#implementors-list .impl:nth-child(2) > a.anchor")
 assert-attribute: ("#implementors-list .impl:nth-child(2)", {"id": "impl-Whatever-1"})
 assert-attribute: ("#implementors-list .impl:nth-child(2) > a.anchor", {"href": "#impl-Whatever-1"})
-assert: "#implementors-list .impl:nth-child(2) > .code-header.in-band"
+assert: "#implementors-list .impl:nth-child(2) > .code-header"
 
 goto: file://|DOC_PATH|/test_docs/struct.HasEmptyTraits.html
 compare-elements-position-near-false: (
     "#impl-EmptyTrait1-for-HasEmptyTraits",
     "#impl-EmptyTrait2-for-HasEmptyTraits",
-    {"y": 30},
+    {"y": 34},
 )
 compare-elements-position-near: (
     "#impl-EmptyTrait3-for-HasEmptyTraits h3",
     "#impl-EmptyTrait3-for-HasEmptyTraits .item-info",
-    {"y": 30},
+    {"y": 34},
 )
 
 // Now check that re-exports work correctly.
diff --git a/src/test/rustdoc-gui/item-info-alignment.goml b/src/test/rustdoc-gui/item-info-alignment.goml
new file mode 100644
index 000000000000..4d7b5045f7c1
--- /dev/null
+++ b/src/test/rustdoc-gui/item-info-alignment.goml
@@ -0,0 +1,10 @@
+// This test ensures that the "item-info" looks about the same
+// whether or not it's inside a toggle.
+goto: file://|DOC_PATH|/lib2/struct.ItemInfoAlignmentTest.html
+
+// First, we try it in "desktop" mode.
+size: (1200, 870)
+compare-elements-position: (".impl-items > .item-info", "summary > .item-info", ("x"))
+// Next, we try it in "mobile" mode (max-width: 700px).
+size: (650, 650)
+compare-elements-position: (".impl-items > .item-info", "summary > .item-info", ("x"))
diff --git a/src/test/rustdoc-gui/item-info-overflow.goml b/src/test/rustdoc-gui/item-info-overflow.goml
index b7095a3c5324..bc3addd33dd3 100644
--- a/src/test/rustdoc-gui/item-info-overflow.goml
+++ b/src/test/rustdoc-gui/item-info-overflow.goml
@@ -3,8 +3,8 @@ goto: file://|DOC_PATH|/lib2/struct.LongItemInfo.html
 // We set a fixed size so there is no chance of "random" resize.
 size: (1200, 870)
 // Logically, the "item-decl" and the "item-info" should have the same scroll width.
-compare-elements-property: (".docblock.item-decl", ".item-info", ["scrollWidth"])
-assert-property: (".item-info", {"scrollWidth": "890"})
+compare-elements-property: (".item-decl", ".item-info", ["scrollWidth"])
+assert-property: (".item-info", {"scrollWidth": "940"})
 // Just to be sure we're comparing the correct "item-info":
 assert-text: (
     ".item-info",
@@ -21,7 +21,7 @@ compare-elements-property: (
 )
 assert-property: (
     "#impl-SimpleTrait-for-LongItemInfo2 .item-info",
-    {"scrollWidth": "866"},
+    {"scrollWidth": "916"},
 )
 // Just to be sure we're comparing the correct "item-info":
 assert-text: (
diff --git a/src/test/rustdoc-gui/item-info.goml b/src/test/rustdoc-gui/item-info.goml
index 50c45b76bd63..8750d5c53606 100644
--- a/src/test/rustdoc-gui/item-info.goml
+++ b/src/test/rustdoc-gui/item-info.goml
@@ -4,9 +4,9 @@ goto: file://|DOC_PATH|/lib2/struct.Foo.html
 // We set a fixed size so there is no chance of "random" resize.
 size: (1100, 800)
 // We check that ".item-info" is bigger than its content.
-assert-css: (".item-info", {"width": "790px"})
+assert-css: (".item-info", {"width": "840px"})
 assert-css: (".item-info .stab", {"width": "289px"})
-assert-position: (".item-info .stab", {"x": 295})
+assert-position: (".item-info .stab", {"x": 245})
 
 // Now we ensure that they're not rendered on the same line.
 goto: file://|DOC_PATH|/lib2/trait.Trait.html
diff --git a/src/test/rustdoc-gui/label-next-to-symbol.goml b/src/test/rustdoc-gui/label-next-to-symbol.goml
index f9081189a860..4b4cea2621ff 100644
--- a/src/test/rustdoc-gui/label-next-to-symbol.goml
+++ b/src/test/rustdoc-gui/label-next-to-symbol.goml
@@ -31,15 +31,9 @@ compare-elements-position: (
 )
 
 // Ensure no wrap
-compare-elements-position-near: (
-    "//*[@class='item-left module-item']//a[text()='replaced_function']",
-    "//*[@class='item-right docblock-short']//p[text()='a thing with a label']",
-    {"y": 2},
-)
-// compare parent elements
 compare-elements-position: (
     "//*[@class='item-left module-item']//a[text()='replaced_function']/..",
-    "//*[@class='item-right docblock-short']//p[text()='a thing with a label']/..",
+    "//*[@class='item-right docblock-short'][text()='a thing with a label']",
     ("y"),
 )
 
@@ -60,19 +54,13 @@ compare-elements-position: (
 )
 
 // Ensure wrap
-compare-elements-position-near-false: (
-    "//*[@class='item-left module-item']//a[text()='replaced_function']",
-    "//*[@class='item-right docblock-short']//p[text()='a thing with a label']",
-    {"y": 12},
-)
-// compare parent elements
 compare-elements-position-false: (
     "//*[@class='item-left module-item']//a[text()='replaced_function']/..",
-    "//*[@class='item-right docblock-short']//p[text()='a thing with a label']/..",
+    "//*[@class='item-right docblock-short'][text()='a thing with a label']",
     ("y"),
 )
 compare-elements-position-false: (
     ".item-left .stab.deprecated",
-    "//*[@class='item-right docblock-short']//p[text()='a thing with a label']",
+    "//*[@class='item-right docblock-short'][text()='a thing with a label']",
     ("y"),
 )
diff --git a/src/test/rustdoc-gui/links-color.goml b/src/test/rustdoc-gui/links-color.goml
new file mode 100644
index 000000000000..69c5b4a6733a
--- /dev/null
+++ b/src/test/rustdoc-gui/links-color.goml
@@ -0,0 +1,85 @@
+// This test checks links colors.
+goto: file://|DOC_PATH|/test_docs/index.html
+
+// This is needed so that the text color is computed.
+show-text: true
+
+// Ayu theme
+local-storage: {
+    "rustdoc-theme": "ayu",
+    "rustdoc-use-system-theme": "false",
+}
+reload:
+
+assert-css: (".item-table .mod", {"color": "rgb(57, 175, 215)"}, ALL)
+assert-css: (".item-table .macro", {"color": "rgb(163, 122, 204)"}, ALL)
+assert-css: (".item-table .struct", {"color": "rgb(255, 160, 165)"}, ALL)
+assert-css: (".item-table .enum", {"color": "rgb(255, 160, 165)"}, ALL)
+assert-css: (".item-table .trait", {"color": "rgb(57, 175, 215)"}, ALL)
+assert-css: (".item-table .fn", {"color": "rgb(253, 214, 135)"}, ALL)
+assert-css: (".item-table .type", {"color": "rgb(255, 160, 165)"}, ALL)
+assert-css: (".item-table .union", {"color": "rgb(255, 160, 165)"}, ALL)
+assert-css: (".item-table .keyword", {"color": "rgb(57, 175, 215)"}, ALL)
+
+assert-css: (
+    ".sidebar-elems a:not(.current)",
+    {"color": "rgb(83, 177, 219)", "background-color": "rgba(0, 0, 0, 0)", "font-weight": "400"},
+    ALL,
+)
+assert-css: (
+    ".sidebar-elems a.current",
+    {"color": "rgb(255, 180, 76)", "background-color": "rgba(0, 0, 0, 0)", "font-weight": "500"},
+    ALL,
+)
+
+
+// Dark theme
+local-storage: {"rustdoc-theme": "dark"}
+reload:
+
+assert-css: (".item-table .mod", {"color": "rgb(210, 153, 29)"}, ALL)
+assert-css: (".item-table .macro", {"color": "rgb(9, 189, 0)"}, ALL)
+assert-css: (".item-table .struct", {"color": "rgb(45, 191, 184)"}, ALL)
+assert-css: (".item-table .enum", {"color": "rgb(45, 191, 184)"}, ALL)
+assert-css: (".item-table .trait", {"color": "rgb(183, 140, 242)"}, ALL)
+assert-css: (".item-table .fn", {"color": "rgb(43, 171, 99)"}, ALL)
+assert-css: (".item-table .type", {"color": "rgb(45, 191, 184)"}, ALL)
+assert-css: (".item-table .union", {"color": "rgb(45, 191, 184)"}, ALL)
+assert-css: (".item-table .keyword", {"color": "rgb(210, 153, 29)"}, ALL)
+
+assert-css: (
+    ".sidebar-elems a:not(.current)",
+    {"color": "rgb(253, 191, 53)", "background-color": "rgba(0, 0, 0, 0)", "font-weight": "400"},
+    ALL,
+)
+assert-css: (
+    ".sidebar-elems a.current",
+    {"color": "rgb(253, 191, 53)", "background-color": "rgb(68, 68, 68)", "font-weight": "500"},
+    ALL,
+)
+
+
+// Light theme
+local-storage: {"rustdoc-theme": "light"}
+reload:
+
+assert-css: (".item-table .mod", {"color": "rgb(56, 115, 173)"}, ALL)
+assert-css: (".item-table .macro", {"color": "rgb(6, 128, 0)"}, ALL)
+assert-css: (".item-table .struct", {"color": "rgb(173, 55, 138)"}, ALL)
+assert-css: (".item-table .enum", {"color": "rgb(173, 55, 138)"}, ALL)
+assert-css: (".item-table .trait", {"color": "rgb(110, 79, 201)"}, ALL)
+assert-css: (".item-table .fn", {"color": "rgb(173, 124, 55)"}, ALL)
+assert-css: (".item-table .type", {"color": "rgb(173, 55, 138)"}, ALL)
+assert-css: (".item-table .union", {"color": "rgb(173, 55, 138)"}, ALL)
+assert-css: (".item-table .keyword", {"color": "rgb(56, 115, 173)"}, ALL)
+
+assert-css: (
+    ".sidebar-elems a:not(.current)",
+    {"color": "rgb(53, 109, 164)", "background-color": "rgba(0, 0, 0, 0)", "font-weight": "400"},
+    ALL,
+)
+assert-css: (
+    ".sidebar-elems a.current",
+    {"color": "rgb(53, 109, 164)", "background-color": "rgb(255, 255, 255)", "font-weight": "500"},
+    ALL,
+)
diff --git a/src/test/rustdoc-gui/notable-trait.goml b/src/test/rustdoc-gui/notable-trait.goml
new file mode 100644
index 000000000000..20a129f9d9da
--- /dev/null
+++ b/src/test/rustdoc-gui/notable-trait.goml
@@ -0,0 +1,91 @@
+// This test checks the position of the `i` for the notable traits.
+goto: file://|DOC_PATH|/test_docs/struct.NotableStructWithLongName.html
+show-text: true
+// We start with a wide screen.
+size: (1100, 600)
+// Checking they have the same y position.
+compare-elements-position: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("y"),
+)
+// Checking they don't have the same x position.
+compare-elements-position-false: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("x"),
+)
+// The `i` should be *after* the type.
+assert-position: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    {"x": 677},
+)
+assert-position: (
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    {"x": 951},
+)
+
+
+// Now only the `i` should be on the next line.
+size: (1055, 600)
+compare-elements-position-false: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("y", "x"),
+)
+
+// Now both the `i` and the struct name should be on the next line.
+size: (980, 600)
+// Checking they have the same y position.
+compare-elements-position: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("y"),
+)
+// Checking they don't have the same x position.
+compare-elements-position-false: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("x"),
+)
+// The `i` should be *after* the type.
+assert-position: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    {"x": 245},
+)
+assert-position: (
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    {"x": 519},
+)
+
+// Checking on mobile now.
+size: (650, 600)
+// Checking they have the same y position.
+compare-elements-position: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("y"),
+)
+// Checking they don't have the same x position.
+compare-elements-position-false: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("x"),
+)
+// The `i` should be *after* the type.
+assert-position: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    {"x": 15},
+)
+assert-position: (
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    {"x": 289},
+)
+
+// Checking on very small mobile. The `i` should be on its own line.
+size: (365, 600)
+compare-elements-position-false: (
+    "//*[@id='method.create_an_iterator_from_read']//a[text()='NotableStructWithLongName']",
+    "//*[@id='method.create_an_iterator_from_read']//*[@class='notable-traits']",
+    ("y", "x"),
+)
diff --git a/src/test/rustdoc-gui/overflow-tooltip-information.goml b/src/test/rustdoc-gui/overflow-tooltip-information.goml
index 7ef85a4c4456..f481f82c234b 100644
--- a/src/test/rustdoc-gui/overflow-tooltip-information.goml
+++ b/src/test/rustdoc-gui/overflow-tooltip-information.goml
@@ -2,7 +2,7 @@
 // have overflow and max-width CSS rules set because they create a bug in firefox on
 // mac. For more information: https://github.com/rust-lang/rust/issues/89185
 goto: file://|DOC_PATH|/test_docs/fn.foo.html
-assert-css: (".docblock > .information", {
+assert-css: (".docblock > .example-wrap .tooltip", {
     "overflow-x": "visible",
     "max-width": "none"
 }, ALL)
diff --git a/src/test/rustdoc-gui/search-form-elements.goml b/src/test/rustdoc-gui/search-form-elements.goml
index c35a86ccd1ca..1c64974e9162 100644
--- a/src/test/rustdoc-gui/search-form-elements.goml
+++ b/src/test/rustdoc-gui/search-form-elements.goml
@@ -92,7 +92,7 @@ reload:
 assert-css: (
     ".search-input",
     {
-        "border-color": "rgb(240, 240, 240)",
+        "border-color": "rgb(224, 224, 224)",
         "background-color": "rgb(240, 240, 240)",
         "color": "rgb(17, 17, 17)",
     },
diff --git a/src/test/rustdoc-gui/search-input.goml b/src/test/rustdoc-gui/search-input.goml
deleted file mode 100644
index 6903e1a1bf5c..000000000000
--- a/src/test/rustdoc-gui/search-input.goml
+++ /dev/null
@@ -1,22 +0,0 @@
-// Ensures that the search input border color changes on focus.
-goto: file://|DOC_PATH|/test_docs/index.html
-local-storage: {"rustdoc-use-system-theme": "false", "rustdoc-theme": "dark"}
-reload:
-
-assert-css: (".search-input", {"border-color": "rgb(240, 240, 240)"})
-click: ".search-input"
-assert-css: (".search-input", {"border-color": "rgb(0, 141, 253)"})
-
-local-storage: {"rustdoc-theme": "light"}
-reload:
-
-assert-css: (".search-input", {"border-color": "rgb(224, 224, 224)"})
-click: ".search-input"
-assert-css: (".search-input", {"border-color": "rgb(102, 175, 233)"})
-
-local-storage: {"rustdoc-theme": "ayu"}
-reload:
-
-assert-css: (".search-input", {"border-color": "rgb(92, 103, 115)"})
-click: ".search-input"
-assert-css: (".search-input", {"border-color": "rgb(92, 103, 115)"})
diff --git a/src/test/rustdoc-gui/search-result-display.goml b/src/test/rustdoc-gui/search-result-display.goml
index db4907924faf..e33693e27eaf 100644
--- a/src/test/rustdoc-gui/search-result-display.goml
+++ b/src/test/rustdoc-gui/search-result-display.goml
@@ -7,11 +7,14 @@ press-key: 'Enter'
 wait-for: "#crate-search"
 // The width is returned by "getComputedStyle" which returns the exact number instead of the
 // CSS rule which is "50%"...
-assert-css: (".search-results div.desc", {"width": "295px"})
+assert-css: (".search-results div.desc", {"width": "318px"})
 size: (600, 100)
 // As counter-intuitive as it may seem, in this width, the width is "100%", which is why
 // when computed it's larger.
-assert-css: (".search-results div.desc", {"width": "570px"})
+assert-css: (".search-results div.desc", {"width": "566px"})
+
+// The result set is all on one line.
+assert-css: (".search-results .result-name > span", {"display": "inline"})
 
 // Check that the crate filter `<select>` is correctly handled when it goes to next line.
 // To do so we need to update the length of one of its `<option>`.
diff --git a/src/test/rustdoc-gui/sidebar-mobile-scroll.goml b/src/test/rustdoc-gui/sidebar-mobile-scroll.goml
index b3bcea253388..dc50185f01b2 100644
--- a/src/test/rustdoc-gui/sidebar-mobile-scroll.goml
+++ b/src/test/rustdoc-gui/sidebar-mobile-scroll.goml
@@ -6,7 +6,7 @@ assert-css: (".sidebar", {"display": "block", "left": "-1000px"})
 
 // Scroll down.
 scroll-to: "//h2[@id='blanket-implementations']"
-assert-window-property: {"pageYOffset": "702"}
+assert-window-property: {"pageYOffset": "643"}
 
 // Open the sidebar menu.
 click: ".sidebar-menu-toggle"
@@ -21,11 +21,11 @@ assert-window-property: {"pageYOffset": "0"}
 // Close the sidebar menu. Make sure the scroll position gets restored.
 click: ".sidebar-menu-toggle"
 wait-for-css: (".sidebar", {"left": "-1000px"})
-assert-window-property: {"pageYOffset": "702"}
+assert-window-property: {"pageYOffset": "643"}
 
 // Now test that scrollability returns when the browser window is just resized.
 click: ".sidebar-menu-toggle"
 wait-for-css: (".sidebar", {"left": "0px"})
 assert-window-property: {"pageYOffset": "0"}
-size: (900, 900)
-assert-window-property: {"pageYOffset": "702"}
+size: (900, 600)
+assert-window-property: {"pageYOffset": "643"}
diff --git a/src/test/rustdoc-gui/sidebar-source-code-display.goml b/src/test/rustdoc-gui/sidebar-source-code-display.goml
index e4662a10ed5d..4321efcdb171 100644
--- a/src/test/rustdoc-gui/sidebar-source-code-display.goml
+++ b/src/test/rustdoc-gui/sidebar-source-code-display.goml
@@ -224,14 +224,14 @@ click: "#sidebar-toggle"
 wait-for-css: (".sidebar", {"width": "0px"})
 // We scroll to line 117 to change the scroll position.
 scroll-to: '//*[@id="117"]'
-assert-window-property: {"pageYOffset": "2519"}
+assert-window-property: {"pageYOffset": "2542"}
 // Expanding the sidebar...
 click: "#sidebar-toggle"
 wait-for-css: (".sidebar", {"width": "500px"})
 click: "#sidebar-toggle"
 wait-for-css: (".sidebar", {"width": "0px"})
 // The "scrollTop" property should be the same.
-assert-window-property: {"pageYOffset": "2519"}
+assert-window-property: {"pageYOffset": "2542"}
 
 // We now check that the scroll position is restored if the window is resized.
 size: (500, 700)
@@ -239,7 +239,7 @@ click: "#sidebar-toggle"
 wait-for-css: ("#source-sidebar", {"visibility": "visible"})
 assert-window-property: {"pageYOffset": "0"}
 size: (900, 900)
-assert-window-property: {"pageYOffset": "2519"}
+assert-window-property: {"pageYOffset": "2542"}
 size: (500, 700)
 click: "#sidebar-toggle"
 wait-for-css: ("#source-sidebar", {"visibility": "hidden"})
diff --git a/src/test/rustdoc-gui/sidebar.goml b/src/test/rustdoc-gui/sidebar.goml
index 32fe3334f364..ea7bcc669945 100644
--- a/src/test/rustdoc-gui/sidebar.goml
+++ b/src/test/rustdoc-gui/sidebar.goml
@@ -1,5 +1,6 @@
 // Checks multiple things on the sidebar display (width of its elements, colors, etc).
 goto: file://|DOC_PATH|/test_docs/index.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 show-text: true
 local-storage: {"rustdoc-theme": "light"}
 // We reload the page so the local storage settings are being used.
@@ -39,11 +40,13 @@ assert-property: ("html", {"scrollTop": "0"})
 
 // We now go back to the crate page to click on the "lib2" crate link.
 goto: file://|DOC_PATH|/test_docs/index.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 assert-css: (".sidebar-elems .crate > ul > li:first-child > a", {"color": "rgb(53, 109, 164)"})
 click: ".sidebar-elems .crate > ul > li:first-child > a"
 
 // PAGE: lib2/index.html
 goto: file://|DOC_PATH|/lib2/index.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 assert-text: (".sidebar > .location", "Crate lib2")
 // We check that we have the crates list and that the "current" on is now "lib2".
 assert-text: (".sidebar-elems .crate > ul > li > a.current", "lib2")
@@ -65,11 +68,13 @@ assert-text: (".sidebar .sidebar-elems .location", "In lib2")
 assert-false: ".sidebar-elems > .crate"
 
 goto: ./module/index.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 assert-text: (".sidebar > .location", "Module module")
 // We check that we don't have the crate list.
 assert-false: ".sidebar-elems > .crate"
 
 goto: ./sub_module/sub_sub_module/index.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 assert-text: (".sidebar > .location", "Module sub_sub_module")
 // We check that we don't have the crate list.
 assert-false: ".sidebar-elems .crate"
@@ -78,11 +83,21 @@ assert-text: ("#functions + .item-table .item-left > a", "foo")
 
 // Links to trait implementations in the sidebar should not wrap even if they are long.
 goto: file://|DOC_PATH|/lib2/struct.HasALongTraitWithParams.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 assert-property: (".sidebar-elems section .block li > a", {"offsetHeight": 29})
 
 // Test that clicking on of the "In <module>" headings in the sidebar links to the
 // appropriate anchor in index.html.
 goto: file://|DOC_PATH|/test_docs/struct.Foo.html
+assert-property: (".sidebar", {"clientWidth": "200"})
 click: ".block.mod h3 a"
 // PAGE: index.html
 assert-css: ("#modules", {"background-color": "rgb(253, 255, 211)"})
+
+// Finally, assert that the `[+]/[−]` toggle doesn't affect sidebar width.
+click: "#toggle-all-docs"
+assert-text: ("#toggle-all-docs", "[+]")
+assert-property: (".sidebar", {"clientWidth": "200"})
+click: "#toggle-all-docs"
+assert-text: ("#toggle-all-docs", "[−]")
+assert-property: (".sidebar", {"clientWidth": "200"})
\ No newline at end of file
diff --git a/src/test/rustdoc-gui/source-anchor-scroll.goml b/src/test/rustdoc-gui/source-anchor-scroll.goml
index 4e51c8dcac0a..47e40aa8e3b1 100644
--- a/src/test/rustdoc-gui/source-anchor-scroll.goml
+++ b/src/test/rustdoc-gui/source-anchor-scroll.goml
@@ -10,7 +10,7 @@ assert-property: ("html", {"scrollTop": "0"})
 click: '//a[text() = "barbar"]'
 assert-property: ("html", {"scrollTop": "125"})
 click: '//a[text() = "bar"]'
-assert-property: ("html", {"scrollTop": "166"})
+assert-property: ("html", {"scrollTop": "156"})
 click: '//a[text() = "sub_fn"]'
 assert-property: ("html", {"scrollTop": "53"})
 
diff --git a/src/test/rustdoc-gui/src-font-size.goml b/src/test/rustdoc-gui/src-font-size.goml
index 0c01e2545548..9797f196c554 100644
--- a/src/test/rustdoc-gui/src-font-size.goml
+++ b/src/test/rustdoc-gui/src-font-size.goml
@@ -5,7 +5,7 @@ goto: file://|DOC_PATH|/test_docs/struct.Foo.html
 show-text: true
 // Check the impl headers.
 assert-css: (".impl.has-srclink .srclink", {"font-size": "16px"}, ALL)
-assert-css: (".impl.has-srclink .code-header.in-band", {"font-size": "18px"}, ALL)
+assert-css: (".impl.has-srclink .code-header", {"font-size": "18px"}, ALL)
 // Check the impl items.
 assert-css: (".impl-items .has-srclink .srclink", {"font-size": "16px"}, ALL)
 assert-css: (".impl-items .has-srclink .code-header", {"font-size": "16px"}, ALL)
diff --git a/src/test/rustdoc-gui/src/lib2/lib.rs b/src/test/rustdoc-gui/src/lib2/lib.rs
index 87f91be3ac82..5a151ed7b687 100644
--- a/src/test/rustdoc-gui/src/lib2/lib.rs
+++ b/src/test/rustdoc-gui/src/lib2/lib.rs
@@ -143,3 +143,40 @@ pub struct LongItemInfo2;
 /// Some docs.
 #[doc(cfg(any(target_os = "android", target_os = "linux", target_os = "emscripten", target_os = "dragonfly", target_os = "freebsd", target_os = "netbsd", target_os = "openbsd")))]
 impl SimpleTrait for LongItemInfo2 {}
+
+pub struct WhereWhitespace<T>;
+
+impl<T> WhereWhitespace<T> {
+    pub fn new<F>(f: F) -> Self
+    where
+        F: FnMut() -> i32,
+    {}
+}
+
+impl<K, T> Whitespace<&K> for WhereWhitespace<T>
+where
+    K: std::fmt::Debug,
+{
+    type Output = WhereWhitespace<T>;
+    fn index(&self, _key: &K) -> &Self::Output {
+        self
+    }
+}
+
+pub trait Whitespace<Idx>
+where
+    Idx: ?Sized,
+{
+    type Output;
+    fn index(&self, index: Idx) -> &Self::Output;
+}
+
+pub struct ItemInfoAlignmentTest;
+
+impl ItemInfoAlignmentTest {
+    /// This method has docs
+    #[deprecated]
+    pub fn foo() {}
+    #[deprecated]
+    pub fn bar() {}
+}
diff --git a/src/test/rustdoc-gui/src/test_docs/lib.rs b/src/test/rustdoc-gui/src/test_docs/lib.rs
index a02d5934cc24..1c066206c1f2 100644
--- a/src/test/rustdoc-gui/src/test_docs/lib.rs
+++ b/src/test/rustdoc-gui/src/test_docs/lib.rs
@@ -6,6 +6,24 @@
 #![feature(rustdoc_internals)]
 #![feature(doc_cfg)]
 
+/*!
+Enable the feature <span class="stab portability"><code>some-feature</code></span> to enjoy
+this crate even more!
+Enable the feature <span class="stab portability"><code>some-feature</code></span> to enjoy
+this crate even more!
+Enable the feature <span class="stab portability"><code>some-feature</code></span> to enjoy
+this crate even more!
+
+Also, stop using `bar` as it's <span class="stab deprecated" title="">deprecated</span>.
+Also, stop using `bar` as it's <span class="stab deprecated" title="">deprecated</span>.
+Also, stop using `bar` as it's <span class="stab deprecated" title="">deprecated</span>.
+
+Finally, you can use `quz` only on <span class="stab portability"><code>Unix or x86-64</code>
+</span>.
+Finally, you can use `quz` only on <span class="stab portability"><code>Unix or x86-64</code>
+</span>.
+*/
+
 use std::convert::AsRef;
 use std::fmt;
 
@@ -28,6 +46,12 @@ use std::fmt;
 /// Let's say I'm just some text will ya?
 /// ```
 ///
+/// A failing to run one:
+///
+/// ```should_panic
+/// panic!("tadam");
+/// ```
+///
 /// An inlined `code`!
 pub fn foo() {}
 
@@ -319,3 +343,15 @@ pub mod doc_block_table {
     }
 
 }
+
+pub struct NotableStructWithLongName<R>(R);
+
+impl<R: std::io::Read> NotableStructWithLongName<R> {
+    pub fn create_an_iterator_from_read(r: R) -> NotableStructWithLongName<R> { Self(r) }
+}
+
+impl<R: std::io::Read> std::iter::Iterator for NotableStructWithLongName<R> {
+    type Item = ();
+
+    fn next(&mut self) -> Option<Self::Item> { () }
+}
diff --git a/src/test/rustdoc-gui/toggle-click-deadspace.goml b/src/test/rustdoc-gui/toggle-click-deadspace.goml
index 4a328c9f9e06..8c3a0bf5bb78 100644
--- a/src/test/rustdoc-gui/toggle-click-deadspace.goml
+++ b/src/test/rustdoc-gui/toggle-click-deadspace.goml
@@ -4,7 +4,10 @@ goto: file://|DOC_PATH|/lib2/struct.Foo.html
 assert-attribute: (".impl-items .rustdoc-toggle", {"open": ""})
 click: "h4.code-header" // This is the position of "pub" in "pub fn a_method"
 assert-attribute: (".impl-items .rustdoc-toggle", {"open": ""})
-click: ".impl-items .rustdoc-toggle summary::before" // This is the position of "[-]" next to that pub fn.
+click-with-offset: (
+    ".impl-items .rustdoc-toggle summary",
+    {"x": -24, "y": 8}, // This is the position of "[-]" next to that pub fn.
+)
 assert-attribute-false: (".impl-items .rustdoc-toggle", {"open": ""})
 
 // Click the "Trait" part of "impl Trait" and verify it navigates.
diff --git a/src/test/rustdoc-gui/type-declation-overflow.goml b/src/test/rustdoc-gui/type-declation-overflow.goml
index 22212a31728d..505874fa0107 100644
--- a/src/test/rustdoc-gui/type-declation-overflow.goml
+++ b/src/test/rustdoc-gui/type-declation-overflow.goml
@@ -15,7 +15,7 @@ assert-property: (".item-table .struct", {"offsetWidth": "684"})
 goto: file://|DOC_PATH|/lib2/too_long/type.ReallyLongTypeNameLongLongLong.html
 assert-property: ("body", {"scrollWidth": "1100"})
 // We now check that the section width hasn't grown because of it.
-assert-property: ("#main-content", {"scrollWidth": "825"})
+assert-property: ("#main-content", {"scrollWidth": "840"})
 // And now checking that it has scrollable content.
 assert-property: (".item-decl pre", {"scrollWidth": "1103"})
 
@@ -24,7 +24,7 @@ assert-property: (".item-decl pre", {"scrollWidth": "1103"})
 goto: file://|DOC_PATH|/lib2/too_long/constant.ReallyLongTypeNameLongLongLongConstBecauseWhyNotAConstRightGigaGigaSupraLong.html
 assert-property: ("body", {"scrollWidth": "1100"})
 // We now check that the section width hasn't grown because of it.
-assert-property: ("#main-content", {"scrollWidth": "825"})
+assert-property: ("#main-content", {"scrollWidth": "840"})
 // And now checking that it has scrollable content.
 assert-property: (".item-decl pre", {"scrollWidth": "950"})
 
@@ -32,6 +32,6 @@ assert-property: (".item-decl pre", {"scrollWidth": "950"})
 size: (600, 600)
 goto: file://|DOC_PATH|/lib2/too_long/struct.SuperIncrediblyLongLongLongLongLongLongLongGigaGigaGigaMegaLongLongLongStructName.html
 // It shouldn't have an overflow in the topbar either.
-assert-property: (".mobile-topbar .location", {"scrollWidth": "492"})
-assert-property: (".mobile-topbar .location", {"clientWidth": "492"})
+store-property: (scrollWidth, ".mobile-topbar .location", "scrollWidth")
+assert-property: (".mobile-topbar .location", {"clientWidth": |scrollWidth|})
 assert-css: (".mobile-topbar .location", {"overflow-x": "hidden"})
diff --git a/src/test/rustdoc-gui/where-whitespace.goml b/src/test/rustdoc-gui/where-whitespace.goml
new file mode 100644
index 000000000000..1a3ff1f491cb
--- /dev/null
+++ b/src/test/rustdoc-gui/where-whitespace.goml
@@ -0,0 +1,27 @@
+// This test ensures that the where conditions are correctly displayed.
+goto: file://|DOC_PATH|/lib2/trait.Whitespace.html
+show-text: true
+// First, we check in the trait definition if the where clause is "on its own" (not on the same
+// line than "pub trait Whitespace<Idx>").
+compare-elements-position-false: (".item-decl code", ".where.fmt-newline", ("y"))
+// And that the code following it isn't on the same line either.
+compare-elements-position-false: (".item-decl .fnname", ".where.fmt-newline", ("y"))
+
+goto: file://|DOC_PATH|/lib2/struct.WhereWhitespace.html
+// We make the screen a bit wider to ensure that the trait impl is on one line.
+size: (915, 915)
+
+compare-elements-position-false: ("#method\.new .fnname", "#method\.new .where.fmt-newline", ("y"))
+// We ensure that both the trait name and the struct name are on the same line in
+// "impl<K, T> Whitespace<&K> for WhereWhitespace<T>".
+compare-elements-position: (
+    "#trait-implementations-list .impl h3 .trait",
+    "#trait-implementations-list .impl h3 .struct",
+    ("y"),
+)
+// And we now check that the where condition isn't on the same line.
+compare-elements-position-false: (
+    "#trait-implementations-list .impl h3 .trait",
+    "#trait-implementations-list .impl h3 .where.fmt-newline",
+    ("y"),
+)
diff --git a/src/test/rustdoc-json/assoc_items.rs b/src/test/rustdoc-json/assoc_items.rs
index 2eb413fb4020..6d7f6bb969fb 100644
--- a/src/test/rustdoc-json/assoc_items.rs
+++ b/src/test/rustdoc-json/assoc_items.rs
@@ -3,25 +3,35 @@
 pub struct Simple;
 
 impl Simple {
-    // @has "$.index[*][?(@.name=='CONSTANT')].kind" \"assoc_const\"
+    // @is "$.index[*][?(@.name=='CONSTANT')].kind" \"assoc_const\"
     pub const CONSTANT: usize = 0;
 }
 
 pub trait EasyToImpl {
-    // @has "$.index[*][?(@.name=='ToDeclare')].kind" \"assoc_type\"
-    // @has "$.index[*][?(@.name=='ToDeclare')].inner.default" null
+    // @is "$.index[*][?(@.docs=='ToDeclare trait')].kind" \"assoc_type\"
+    // @is "$.index[*][?(@.docs=='ToDeclare trait')].inner.default" null
+    // @is "$.index[*][?(@.docs=='ToDeclare trait')].inner.bounds" []
+    /// ToDeclare trait
     type ToDeclare;
-    // @has "$.index[*][?(@.name=='AN_ATTRIBUTE')].kind" \"assoc_const\"
-    // @has "$.index[*][?(@.name=='AN_ATTRIBUTE')].inner.default" null
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE trait')].kind" \"assoc_const\"
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE trait')].inner.default" null
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE trait')].inner.type.kind" '"primitive"'
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE trait')].inner.type.inner" '"usize"'
+    /// AN_ATTRIBUTE trait
     const AN_ATTRIBUTE: usize;
 }
 
 impl EasyToImpl for Simple {
-    // @has "$.index[*][?(@.name=='ToDeclare')].inner.default.kind" \"primitive\"
-    // @has "$.index[*][?(@.name=='ToDeclare')].inner.default.inner" \"usize\"
+    // @is "$.index[*][?(@.docs=='ToDeclare impl')].kind" '"assoc_type"'
+    // @is "$.index[*][?(@.docs=='ToDeclare impl')].inner.default.kind" \"primitive\"
+    // @is "$.index[*][?(@.docs=='ToDeclare impl')].inner.default.inner" \"usize\"
+    /// ToDeclare impl
     type ToDeclare = usize;
-    // @has "$.index[*][?(@.name=='AN_ATTRIBUTE')].inner.type.kind" \"primitive\"
-    // @has "$.index[*][?(@.name=='AN_ATTRIBUTE')].inner.type.inner" \"usize\"
-    // @has "$.index[*][?(@.name=='AN_ATTRIBUTE')].inner.default" \"12\"
+
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE impl')].kind" '"assoc_const"'
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE impl')].inner.type.kind" \"primitive\"
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE impl')].inner.type.inner" \"usize\"
+    // @is "$.index[*][?(@.docs=='AN_ATTRIBUTE impl')].inner.default" \"12\"
+    /// AN_ATTRIBUTE impl
     const AN_ATTRIBUTE: usize = 12;
 }
diff --git a/src/test/rustdoc-json/enums/discriminant/basic.rs b/src/test/rustdoc-json/enums/discriminant/basic.rs
new file mode 100644
index 000000000000..8c221615aa75
--- /dev/null
+++ b/src/test/rustdoc-json/enums/discriminant/basic.rs
@@ -0,0 +1,12 @@
+#[repr(i8)]
+pub enum Ordering {
+    // @is "$.index[*][?(@.name=='Less')].inner.variant_inner.expr" '"-1"'
+    // @is "$.index[*][?(@.name=='Less')].inner.variant_inner.value" '"-1"'
+    Less = -1,
+    // @is "$.index[*][?(@.name=='Equal')].inner.variant_inner.expr" '"0"'
+    // @is "$.index[*][?(@.name=='Equal')].inner.variant_inner.value" '"0"'
+    Equal = 0,
+    // @is "$.index[*][?(@.name=='Greater')].inner.variant_inner.expr" '"1"'
+    // @is "$.index[*][?(@.name=='Greater')].inner.variant_inner.value" '"1"'
+    Greater = 1,
+}
diff --git a/src/test/rustdoc-json/enums/discriminant/expr.rs b/src/test/rustdoc-json/enums/discriminant/expr.rs
new file mode 100644
index 000000000000..235b0b47381f
--- /dev/null
+++ b/src/test/rustdoc-json/enums/discriminant/expr.rs
@@ -0,0 +1,39 @@
+pub enum Foo {
+    // @is "$.index[*][?(@.name=='Addition')].inner.variant_inner.value" '"0"'
+    // @is "$.index[*][?(@.name=='Addition')].inner.variant_inner.expr" '"{ _ }"'
+    Addition = 0 + 0,
+    // @is "$.index[*][?(@.name=='Bin')].inner.variant_inner.value" '"1"'
+    // @is "$.index[*][?(@.name=='Bin')].inner.variant_inner.expr" '"0b1"'
+    Bin = 0b1,
+    // @is "$.index[*][?(@.name=='Oct')].inner.variant_inner.value" '"2"'
+    // @is "$.index[*][?(@.name=='Oct')].inner.variant_inner.expr" '"0o2"'
+    Oct = 0o2,
+    // @is "$.index[*][?(@.name=='PubConst')].inner.variant_inner.value" '"3"'
+    // @is "$.index[*][?(@.name=='PubConst')].inner.variant_inner.expr" '"THREE"'
+    PubConst = THREE,
+    // @is "$.index[*][?(@.name=='Hex')].inner.variant_inner.value" '"4"'
+    // @is "$.index[*][?(@.name=='Hex')].inner.variant_inner.expr" '"0x4"'
+    Hex = 0x4,
+    // @is "$.index[*][?(@.name=='Cast')].inner.variant_inner.value" '"5"'
+    // @is "$.index[*][?(@.name=='Cast')].inner.variant_inner.expr" '"{ _ }"'
+    Cast = 5 as isize,
+    // @is "$.index[*][?(@.name=='PubCall')].inner.variant_inner.value" '"6"'
+    // @is "$.index[*][?(@.name=='PubCall')].inner.variant_inner.expr" '"{ _ }"'
+    PubCall = six(),
+    // @is "$.index[*][?(@.name=='PrivCall')].inner.variant_inner.value" '"7"'
+    // @is "$.index[*][?(@.name=='PrivCall')].inner.variant_inner.expr" '"{ _ }"'
+    PrivCall = seven(),
+    // @is "$.index[*][?(@.name=='PrivConst')].inner.variant_inner.value" '"8"'
+    // @is "$.index[*][?(@.name=='PrivConst')].inner.variant_inner.expr" '"EIGHT"'
+    PrivConst = EIGHT,
+}
+
+pub const THREE: isize = 3;
+const EIGHT: isize = 8;
+
+pub const fn six() -> isize {
+    6
+}
+const fn seven() -> isize {
+    7
+}
diff --git a/src/test/rustdoc-json/enums/discriminant/limits.rs b/src/test/rustdoc-json/enums/discriminant/limits.rs
new file mode 100644
index 000000000000..8df73d78d237
--- /dev/null
+++ b/src/test/rustdoc-json/enums/discriminant/limits.rs
@@ -0,0 +1,43 @@
+// ignore-tidy-linelength
+#![feature(repr128)]
+#![allow(incomplete_features)]
+
+#[repr(u64)]
+pub enum U64 {
+    // @is "$.index[*][?(@.name=='U64Min')].inner.variant_inner.value" '"0"'
+    // @is "$.index[*][?(@.name=='U64Min')].inner.variant_inner.expr" '"u64::MIN"'
+    U64Min = u64::MIN,
+    // @is "$.index[*][?(@.name=='U64Max')].inner.variant_inner.value" '"18446744073709551615"'
+    // @is "$.index[*][?(@.name=='U64Max')].inner.variant_inner.expr" '"u64::MAX"'
+    U64Max = u64::MAX,
+}
+
+#[repr(i64)]
+pub enum I64 {
+    // @is "$.index[*][?(@.name=='I64Min')].inner.variant_inner.value" '"-9223372036854775808"'
+    // @is "$.index[*][?(@.name=='I64Min')].inner.variant_inner.expr" '"i64::MIN"'
+    I64Min = i64::MIN,
+    // @is "$.index[*][?(@.name=='I64Max')].inner.variant_inner.value" '"9223372036854775807"'
+    // @is "$.index[*][?(@.name=='I64Max')].inner.variant_inner.expr" '"i64::MAX"'
+    I64Max = i64::MAX,
+}
+
+#[repr(u128)]
+pub enum U128 {
+    // @is "$.index[*][?(@.name=='U128Min')].inner.variant_inner.value" '"0"'
+    // @is "$.index[*][?(@.name=='U128Min')].inner.variant_inner.expr" '"u128::MIN"'
+    U128Min = u128::MIN,
+    // @is "$.index[*][?(@.name=='U128Max')].inner.variant_inner.value" '"340282366920938463463374607431768211455"'
+    // @is "$.index[*][?(@.name=='U128Max')].inner.variant_inner.expr" '"u128::MAX"'
+    U128Max = u128::MAX,
+}
+
+#[repr(i128)]
+pub enum I128 {
+    // @is "$.index[*][?(@.name=='I128Min')].inner.variant_inner.value" '"-170141183460469231731687303715884105728"'
+    // @is "$.index[*][?(@.name=='I128Min')].inner.variant_inner.expr" '"i128::MIN"'
+    I128Min = i128::MIN,
+    // @is "$.index[*][?(@.name=='I128Max')].inner.variant_inner.value" '"170141183460469231731687303715884105727"'
+    // @is "$.index[*][?(@.name=='I128Max')].inner.variant_inner.expr" '"i128::MAX"'
+    I128Max = i128::MAX,
+}
diff --git a/src/test/rustdoc-json/enums/discriminant/num_underscore_and_suffix.rs b/src/test/rustdoc-json/enums/discriminant/num_underscore_and_suffix.rs
new file mode 100644
index 000000000000..3417baa0760e
--- /dev/null
+++ b/src/test/rustdoc-json/enums/discriminant/num_underscore_and_suffix.rs
@@ -0,0 +1,15 @@
+#[repr(u32)]
+pub enum Foo {
+    // @is "$.index[*][?(@.name=='Basic')].inner.variant_inner.value" '"0"'
+    // @is "$.index[*][?(@.name=='Basic')].inner.variant_inner.expr" '"0"'
+    Basic = 0,
+    // @is "$.index[*][?(@.name=='Suffix')].inner.variant_inner.value" '"10"'
+    // @is "$.index[*][?(@.name=='Suffix')].inner.variant_inner.expr" '"10u32"'
+    Suffix = 10u32,
+    // @is "$.index[*][?(@.name=='Underscore')].inner.variant_inner.value" '"100"'
+    // @is "$.index[*][?(@.name=='Underscore')].inner.variant_inner.expr" '"1_0_0"'
+    Underscore = 1_0_0,
+    // @is "$.index[*][?(@.name=='SuffixUnderscore')].inner.variant_inner.value" '"1000"'
+    // @is "$.index[*][?(@.name=='SuffixUnderscore')].inner.variant_inner.expr" '"1_0_0_0u32"'
+    SuffixUnderscore = 1_0_0_0u32,
+}
diff --git a/src/test/rustdoc-json/enums/discriminant/only_some_have_discriminant.rs b/src/test/rustdoc-json/enums/discriminant/only_some_have_discriminant.rs
new file mode 100644
index 000000000000..6af944a2219e
--- /dev/null
+++ b/src/test/rustdoc-json/enums/discriminant/only_some_have_discriminant.rs
@@ -0,0 +1,10 @@
+pub enum Foo {
+    // @is "$.index[*][?(@.name=='Has')].inner.variant_inner" '{"expr":"0", "value":"0"}'
+    Has = 0,
+    // @is "$.index[*][?(@.name=='Doesnt')].inner.variant_inner" null
+    Doesnt,
+    // @is "$.index[*][?(@.name=='AlsoDoesnt')].inner.variant_inner" null
+    AlsoDoesnt,
+    // @is "$.index[*][?(@.name=='AlsoHas')].inner.variant_inner" '{"expr":"44", "value":"44"}'
+    AlsoHas = 44,
+}
diff --git a/src/test/rustdoc-json/enum_variant_hidden.rs b/src/test/rustdoc-json/enums/field_hidden.rs
similarity index 96%
rename from src/test/rustdoc-json/enum_variant_hidden.rs
rename to src/test/rustdoc-json/enums/field_hidden.rs
index c5e063a055c5..e6310cc3b997 100644
--- a/src/test/rustdoc-json/enum_variant_hidden.rs
+++ b/src/test/rustdoc-json/enums/field_hidden.rs
@@ -6,7 +6,7 @@
 // @has "$.index[*][?(@.name=='ParseError')]"
 // @has "$.index[*][?(@.name=='UnexpectedEndTag')]"
 // @is "$.index[*][?(@.name=='UnexpectedEndTag')].inner.variant_kind" '"tuple"'
-// @is "$.index[*][?(@.name=='UnexpectedEndTag')].inner.variant_inner" []
+// @is "$.index[*][?(@.name=='UnexpectedEndTag')].inner.variant_inner" [null]
 
 pub enum ParseError {
     UnexpectedEndTag(#[doc(hidden)] u32),
diff --git a/src/test/rustdoc-json/enums/kind.rs b/src/test/rustdoc-json/enums/kind.rs
new file mode 100644
index 000000000000..e9ea3ae23c22
--- /dev/null
+++ b/src/test/rustdoc-json/enums/kind.rs
@@ -0,0 +1,37 @@
+// ignore-tidy-linelength
+
+#![feature(no_core)]
+#![no_core]
+
+pub enum Foo {
+    // @set Unit = "$.index[*][?(@.name=='Unit')].id"
+    // @is "$.index[*][?(@.name=='Unit')].inner.variant_kind" '"plain"'
+    // @is "$.index[*][?(@.name=='Unit')].inner.variant_inner" null
+    Unit,
+    // @set Named = "$.index[*][?(@.name=='Named')].id"
+    // @is "$.index[*][?(@.name=='Named')].inner.variant_kind" '"struct"'
+    // @is "$.index[*][?(@.name=='Named')].inner.variant_inner" '{"fields": [], "fields_stripped": false}'
+    Named {},
+    // @set Tuple = "$.index[*][?(@.name=='Tuple')].id"
+    // @is "$.index[*][?(@.name=='Tuple')].inner.variant_kind" '"tuple"'
+    // @is "$.index[*][?(@.name=='Tuple')].inner.variant_inner" []
+    Tuple(),
+    // @set NamedField = "$.index[*][?(@.name=='NamedField')].id"
+    // @set x = "$.index[*][?(@.name=='x' && @.kind=='struct_field')].id"
+    // @is "$.index[*][?(@.name=='NamedField')].inner.variant_kind" '"struct"'
+    // @is "$.index[*][?(@.name=='NamedField')].inner.variant_inner.fields[*]" $x
+    // @is "$.index[*][?(@.name=='NamedField')].inner.variant_inner.fields_stripped" false
+    NamedField { x: i32 },
+    // @set TupleField = "$.index[*][?(@.name=='TupleField')].id"
+    // @is "$.index[*][?(@.name=='TupleField')].inner.variant_kind" '"tuple"'
+    // @set tup_field = "$.index[*][?(@.name=='0' && @.kind=='struct_field')].id"
+    // @is "$.index[*][?(@.name=='TupleField')].inner.variant_inner[*]" $tup_field
+    TupleField(i32),
+}
+
+// @is    "$.index[*][?(@.name=='Foo')].inner.variants[0]" $Unit
+// @is    "$.index[*][?(@.name=='Foo')].inner.variants[1]" $Named
+// @is    "$.index[*][?(@.name=='Foo')].inner.variants[2]" $Tuple
+// @is    "$.index[*][?(@.name=='Foo')].inner.variants[3]" $NamedField
+// @is    "$.index[*][?(@.name=='Foo')].inner.variants[4]" $TupleField
+// @count "$.index[*][?(@.name=='Foo')].inner.variants[*]" 5
diff --git a/src/test/rustdoc-json/enums/struct_field_hidden.rs b/src/test/rustdoc-json/enums/struct_field_hidden.rs
new file mode 100644
index 000000000000..f612a34a4927
--- /dev/null
+++ b/src/test/rustdoc-json/enums/struct_field_hidden.rs
@@ -0,0 +1,17 @@
+pub enum Foo {
+    Variant {
+        #[doc(hidden)]
+        a: i32,
+        // @set b = "$.index[*][?(@.name=='b')].id"
+        b: i32,
+        #[doc(hidden)]
+        x: i32,
+        // @set y = "$.index[*][?(@.name=='y')].id"
+        y: i32,
+    },
+    // @is "$.index[*][?(@.name=='Variant')].inner.variant_kind" '"struct"'
+    // @is "$.index[*][?(@.name=='Variant')].inner.variant_inner.fields_stripped" true
+    // @is "$.index[*][?(@.name=='Variant')].inner.variant_inner.fields[0]" $b
+    // @is "$.index[*][?(@.name=='Variant')].inner.variant_inner.fields[1]" $y
+    // @count "$.index[*][?(@.name=='Variant')].inner.variant_inner.fields[*]" 2
+}
diff --git a/src/test/rustdoc-json/enums/tuple_fields_hidden.rs b/src/test/rustdoc-json/enums/tuple_fields_hidden.rs
new file mode 100644
index 000000000000..f546eaa0d172
--- /dev/null
+++ b/src/test/rustdoc-json/enums/tuple_fields_hidden.rs
@@ -0,0 +1,94 @@
+#![feature(no_core)]
+#![no_core]
+
+// @set 1.1.0 = "$.index[*][?(@.docs=='1.1.0')].id"
+// @set 2.1.0 = "$.index[*][?(@.docs=='2.1.0')].id"
+// @set 2.1.1 = "$.index[*][?(@.docs=='2.1.1')].id"
+// @set 2.2.1 = "$.index[*][?(@.docs=='2.2.1')].id"
+// @set 2.3.0 = "$.index[*][?(@.docs=='2.3.0')].id"
+// @set 3.1.1 = "$.index[*][?(@.docs=='3.1.1')].id"
+// @set 3.1.2 = "$.index[*][?(@.docs=='3.1.2')].id"
+// @set 3.2.0 = "$.index[*][?(@.docs=='3.2.0')].id"
+// @set 3.2.2 = "$.index[*][?(@.docs=='3.2.2')].id"
+// @set 3.3.0 = "$.index[*][?(@.docs=='3.3.0')].id"
+// @set 3.3.1 = "$.index[*][?(@.docs=='3.3.1')].id"
+
+pub enum EnumWithStrippedTupleVariants {
+    // @is    "$.index[*][?(@.name=='None')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='None')].inner.variant_inner[*]" 0
+    None(),
+
+    // @is    "$.index[*][?(@.name=='One')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='One')].inner.variant_inner[*]" 1
+    // @is    "$.index[*][?(@.name=='One')].inner.variant_inner[0]" $1.1.0
+    One(/** 1.1.0*/ bool),
+    // @is    "$.index[*][?(@.name=='OneHidden')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='OneHidden')].inner.variant_inner[*]" 1
+    // @is    "$.index[*][?(@.name=='OneHidden')].inner.variant_inner[0]" null
+    OneHidden(#[doc(hidden)] bool),
+
+    // @is    "$.index[*][?(@.name=='Two')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='Two')].inner.variant_inner[*]" 2
+    // @is    "$.index[*][?(@.name=='Two')].inner.variant_inner[0]" $2.1.0
+    // @is    "$.index[*][?(@.name=='Two')].inner.variant_inner[1]" $2.1.1
+    Two(/** 2.1.0*/ bool, /** 2.1.1*/ bool),
+    // @is    "$.index[*][?(@.name=='TwoLeftHidden')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='TwoLeftHidden')].inner.variant_inner[*]" 2
+    // @is    "$.index[*][?(@.name=='TwoLeftHidden')].inner.variant_inner[0]" null
+    // @is    "$.index[*][?(@.name=='TwoLeftHidden')].inner.variant_inner[1]" $2.2.1
+    TwoLeftHidden(#[doc(hidden)] bool, /** 2.2.1*/ bool),
+    // @is    "$.index[*][?(@.name=='TwoRightHidden')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='TwoRightHidden')].inner.variant_inner[*]" 2
+    // @is    "$.index[*][?(@.name=='TwoRightHidden')].inner.variant_inner[0]" $2.3.0
+    // @is    "$.index[*][?(@.name=='TwoRightHidden')].inner.variant_inner[1]" null
+    TwoRightHidden(/** 2.3.0*/ bool, #[doc(hidden)] bool),
+    // @is    "$.index[*][?(@.name=='TwoBothHidden')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='TwoBothHidden')].inner.variant_inner[*]" 2
+    // @is    "$.index[*][?(@.name=='TwoBothHidden')].inner.variant_inner[0]" null
+    // @is    "$.index[*][?(@.name=='TwoBothHidden')].inner.variant_inner[1]" null
+    TwoBothHidden(#[doc(hidden)] bool, #[doc(hidden)] bool),
+
+    // @is    "$.index[*][?(@.name=='Three1')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='Three1')].inner.variant_inner[*]" 3
+    // @is    "$.index[*][?(@.name=='Three1')].inner.variant_inner[0]" null
+    // @is    "$.index[*][?(@.name=='Three1')].inner.variant_inner[1]" $3.1.1
+    // @is    "$.index[*][?(@.name=='Three1')].inner.variant_inner[2]" $3.1.2
+    Three1(#[doc(hidden)] bool, /** 3.1.1*/ bool, /** 3.1.2*/ bool),
+    // @is    "$.index[*][?(@.name=='Three2')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='Three2')].inner.variant_inner[*]" 3
+    // @is    "$.index[*][?(@.name=='Three2')].inner.variant_inner[0]" $3.2.0
+    // @is    "$.index[*][?(@.name=='Three2')].inner.variant_inner[1]" null
+    // @is    "$.index[*][?(@.name=='Three2')].inner.variant_inner[2]" $3.2.2
+    Three2(/** 3.2.0*/ bool, #[doc(hidden)] bool, /** 3.2.2*/ bool),
+    // @is    "$.index[*][?(@.name=='Three3')].inner.variant_kind" '"tuple"'
+    // @count "$.index[*][?(@.name=='Three3')].inner.variant_inner[*]" 3
+    // @is    "$.index[*][?(@.name=='Three3')].inner.variant_inner[0]" $3.3.0
+    // @is    "$.index[*][?(@.name=='Three3')].inner.variant_inner[1]" $3.3.1
+    // @is    "$.index[*][?(@.name=='Three3')].inner.variant_inner[2]" null
+    Three3(/** 3.3.0*/ bool, /** 3.3.1*/ bool, #[doc(hidden)] bool),
+}
+
+
+// @is "$.index[*][?(@.docs=='1.1.0')].name" '"0"'
+// @is "$.index[*][?(@.docs=='2.1.0')].name" '"0"'
+// @is "$.index[*][?(@.docs=='2.1.1')].name" '"1"'
+// @is "$.index[*][?(@.docs=='2.2.1')].name" '"1"'
+// @is "$.index[*][?(@.docs=='2.3.0')].name" '"0"'
+// @is "$.index[*][?(@.docs=='3.1.1')].name" '"1"'
+// @is "$.index[*][?(@.docs=='3.1.2')].name" '"2"'
+// @is "$.index[*][?(@.docs=='3.2.0')].name" '"0"'
+// @is "$.index[*][?(@.docs=='3.2.2')].name" '"2"'
+// @is "$.index[*][?(@.docs=='3.3.0')].name" '"0"'
+// @is "$.index[*][?(@.docs=='3.3.1')].name" '"1"'
+
+// @is "$.index[*][?(@.docs=='1.1.0')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='2.1.0')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='2.1.1')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='2.2.1')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='2.3.0')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='3.1.1')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='3.1.2')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='3.2.0')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='3.2.2')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='3.3.0')].inner" '{"kind": "primitive", "inner": "bool"}'
+// @is "$.index[*][?(@.docs=='3.3.1')].inner" '{"kind": "primitive", "inner": "bool"}'
diff --git a/src/test/rustdoc-json/enums/variant_struct.rs b/src/test/rustdoc-json/enums/variant_struct.rs
index 704ec35d2f0b..23b854d8d172 100644
--- a/src/test/rustdoc-json/enums/variant_struct.rs
+++ b/src/test/rustdoc-json/enums/variant_struct.rs
@@ -1,9 +1,9 @@
-// @has "$.index[*][?(@.name=='EnumStruct')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='EnumStruct')].kind" \"enum\"
+// @is "$.index[*][?(@.name=='EnumStruct')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='EnumStruct')].kind" \"enum\"
 pub enum EnumStruct {
-    // @has "$.index[*][?(@.name=='VariantS')].inner.variant_kind" \"struct\"
-    // @has "$.index[*][?(@.name=='x')].kind" \"struct_field\"
-    // @has "$.index[*][?(@.name=='y')].kind" \"struct_field\"
+    // @is "$.index[*][?(@.name=='VariantS')].inner.variant_kind" \"struct\"
+    // @is "$.index[*][?(@.name=='x')].kind" \"struct_field\"
+    // @is "$.index[*][?(@.name=='y')].kind" \"struct_field\"
     VariantS {
         x: u32,
         y: String,
diff --git a/src/test/rustdoc-json/enums/variant_tuple_struct.rs b/src/test/rustdoc-json/enums/variant_tuple_struct.rs
index 71ddd73ec76a..b71ec47a804a 100644
--- a/src/test/rustdoc-json/enums/variant_tuple_struct.rs
+++ b/src/test/rustdoc-json/enums/variant_tuple_struct.rs
@@ -1,8 +1,8 @@
-// @has "$.index[*][?(@.name=='EnumTupleStruct')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='EnumTupleStruct')].kind" \"enum\"
+// @is "$.index[*][?(@.name=='EnumTupleStruct')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='EnumTupleStruct')].kind" \"enum\"
 pub enum EnumTupleStruct {
-    // @has "$.index[*][?(@.name=='VariantA')].inner.variant_kind" \"tuple\"
-    // @has "$.index[*][?(@.name=='0')].kind" \"struct_field\"
-    // @has "$.index[*][?(@.name=='1')].kind" \"struct_field\"
+    // @is "$.index[*][?(@.name=='VariantA')].inner.variant_kind" \"tuple\"
+    // @is "$.index[*][?(@.name=='0')].kind" \"struct_field\"
+    // @is "$.index[*][?(@.name=='1')].kind" \"struct_field\"
     VariantA(u32, String),
 }
diff --git a/src/test/rustdoc-json/fns/generics.rs b/src/test/rustdoc-json/fns/generics.rs
index e47c8c25513f..7b70ff1df6b0 100644
--- a/src/test/rustdoc-json/fns/generics.rs
+++ b/src/test/rustdoc-json/fns/generics.rs
@@ -9,16 +9,16 @@ pub trait Wham {}
 // @is    "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.where_predicates" []
 // @count "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.params[*]" 1
 // @is    "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.params[0].name" '"T"'
-// @has   "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.params[0].kind.type.synthetic" false
-// @has   "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.params[0].kind.type.bounds[0].trait_bound.trait.id" $wham_id
+// @is    "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.params[0].kind.type.synthetic" false
+// @is    "$.index[*][?(@.name=='one_generic_param_fn')].inner.generics.params[0].kind.type.bounds[0].trait_bound.trait.id" $wham_id
 // @is    "$.index[*][?(@.name=='one_generic_param_fn')].inner.decl.inputs" '[["w", {"inner": "T", "kind": "generic"}]]'
 pub fn one_generic_param_fn<T: Wham>(w: T) {}
 
 // @is    "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.where_predicates" []
 // @count "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.params[*]" 1
 // @is    "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.params[0].name" '"impl Wham"'
-// @has   "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.params[0].kind.type.synthetic" true
-// @has   "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.params[0].kind.type.bounds[0].trait_bound.trait.id" $wham_id
+// @is    "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.params[0].kind.type.synthetic" true
+// @is    "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.generics.params[0].kind.type.bounds[0].trait_bound.trait.id" $wham_id
 // @count "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.decl.inputs[*]" 1
 // @is    "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.decl.inputs[0][0]" '"w"'
 // @is    "$.index[*][?(@.name=='one_synthetic_generic_param_fn')].inner.decl.inputs[0][1].kind" '"impl_trait"'
diff --git a/src/test/rustdoc-json/generic-associated-types/gats.rs b/src/test/rustdoc-json/generic-associated-types/gats.rs
index cbaa0621dc2b..e5809783aeca 100644
--- a/src/test/rustdoc-json/generic-associated-types/gats.rs
+++ b/src/test/rustdoc-json/generic-associated-types/gats.rs
@@ -1,7 +1,7 @@
 // ignore-tidy-linelength
 
 #![no_core]
-#![feature(generic_associated_types, lang_items, no_core)]
+#![feature(lang_items, no_core)]
 
 #[lang = "sized"]
 pub trait Sized {}
diff --git a/src/test/rustdoc-json/impls/auxiliary/foreign_struct.rs b/src/test/rustdoc-json/impls/auxiliary/foreign_struct.rs
new file mode 100644
index 000000000000..832d0fce5990
--- /dev/null
+++ b/src/test/rustdoc-json/impls/auxiliary/foreign_struct.rs
@@ -0,0 +1 @@
+pub struct ForeignStruct;
diff --git a/src/test/rustdoc-json/impls/auxiliary/foreign_trait.rs b/src/test/rustdoc-json/impls/auxiliary/foreign_trait.rs
new file mode 100644
index 000000000000..2c81bee61282
--- /dev/null
+++ b/src/test/rustdoc-json/impls/auxiliary/foreign_trait.rs
@@ -0,0 +1 @@
+pub trait ForeignTrait {}
diff --git a/src/test/rustdoc-json/impls/foreign_for_local.rs b/src/test/rustdoc-json/impls/foreign_for_local.rs
new file mode 100644
index 000000000000..290c2d571e87
--- /dev/null
+++ b/src/test/rustdoc-json/impls/foreign_for_local.rs
@@ -0,0 +1,18 @@
+// aux-build: foreign_trait.rs
+extern crate foreign_trait;
+
+/// ForeignTrait id hack
+pub use foreign_trait::ForeignTrait as _;
+// @set ForeignTrait = "$.index[*][?(@.docs=='ForeignTrait id hack')].inner.id"
+
+pub struct LocalStruct;
+// @set LocalStruct = "$.index[*][?(@.name=='LocalStruct')].id"
+
+/// foreign for local
+impl foreign_trait::ForeignTrait for LocalStruct {}
+
+// @set impl = "$.index[*][?(@.docs=='foreign for local')].id"
+// @is "$.index[*][?(@.docs=='foreign for local')].inner.for.inner.id" $LocalStruct
+// @is "$.index[*][?(@.docs=='foreign for local')].inner.trait.id" $ForeignTrait
+
+// @has "$.index[*][?(@.name=='LocalStruct')].inner.impls[*]" $impl
diff --git a/src/test/rustdoc-json/impls/import_from_private.rs b/src/test/rustdoc-json/impls/import_from_private.rs
index a34046ac12fb..856f7c7015b3 100644
--- a/src/test/rustdoc-json/impls/import_from_private.rs
+++ b/src/test/rustdoc-json/impls/import_from_private.rs
@@ -16,9 +16,7 @@ mod bar {
 // @set import = "$.index[*][?(@.kind=='import')].id"
 pub use bar::Baz;
 
-// FIXME(adotinthevoid): Use hasexact once #99474 lands
-
-// @has "$.index[*][?(@.kind=='module')].inner.items[*]" $import
-// @is  "$.index[*][?(@.kind=='import')].inner.id" $baz
-// @has "$.index[*][?(@.kind=='struct')].inner.impls[*]" $impl
-// @has "$.index[*][?(@.kind=='impl')].inner.items[*]" $doit
+// @is "$.index[*][?(@.kind=='module')].inner.items[*]" $import
+// @is "$.index[*][?(@.kind=='import')].inner.id" $baz
+// @is "$.index[*][?(@.kind=='struct')].inner.impls[*]" $impl
+// @is "$.index[*][?(@.kind=='impl')].inner.items[*]" $doit
diff --git a/src/test/rustdoc-json/impls/local_for_foreign.rs b/src/test/rustdoc-json/impls/local_for_foreign.rs
new file mode 100644
index 000000000000..74f2f08b5a42
--- /dev/null
+++ b/src/test/rustdoc-json/impls/local_for_foreign.rs
@@ -0,0 +1,18 @@
+// aux-build: foreign_struct.rs
+extern crate foreign_struct;
+
+/// ForeignStruct id hack
+pub use foreign_struct::ForeignStruct as _;
+// @set ForeignStruct = "$.index[*][?(@.docs=='ForeignStruct id hack')].inner.id"
+
+pub trait LocalTrait {}
+// @set LocalTrait = "$.index[*][?(@.name=='LocalTrait')].id"
+
+/// local for foreign
+impl LocalTrait for foreign_struct::ForeignStruct {}
+
+// @set impl = "$.index[*][?(@.docs=='local for foreign')].id"
+// @is "$.index[*][?(@.docs=='local for foreign')].inner.trait.id" $LocalTrait
+// @is "$.index[*][?(@.docs=='local for foreign')].inner.for.inner.id" $ForeignStruct
+
+// @is "$.index[*][?(@.name=='LocalTrait')].inner.implementations[*]" $impl
diff --git a/src/test/rustdoc-json/impls/local_for_local.rs b/src/test/rustdoc-json/impls/local_for_local.rs
new file mode 100644
index 000000000000..93dedb7ec92d
--- /dev/null
+++ b/src/test/rustdoc-json/impls/local_for_local.rs
@@ -0,0 +1,15 @@
+#![feature(no_core)]
+#![no_core]
+
+// @set struct = "$.index[*][?(@.name=='Struct')].id"
+pub struct Struct;
+// @set trait = "$.index[*][?(@.name=='Trait')].id"
+pub trait Trait {}
+// @set impl = "$.index[*][?(@.docs=='impl')].id"
+/// impl
+impl Trait for Struct {}
+
+// @is "$.index[*][?(@.name=='Struct')].inner.impls[*]" $impl
+// @is "$.index[*][?(@.name=='Trait')].inner.implementations[*]" $impl
+// @is "$.index[*][?(@.docs=='impl')].inner.trait.id" $trait
+// @is "$.index[*][?(@.docs=='impl')].inner.for.inner.id" $struct
diff --git a/src/test/rustdoc-json/impls/local_for_local_primitive.rs b/src/test/rustdoc-json/impls/local_for_local_primitive.rs
new file mode 100644
index 000000000000..38e7e2658dfd
--- /dev/null
+++ b/src/test/rustdoc-json/impls/local_for_local_primitive.rs
@@ -0,0 +1,21 @@
+#![feature(no_core)]
+#![feature(rustdoc_internals)]
+#![no_core]
+
+// @set Local = "$.index[*][?(@.name=='Local')].id"
+pub trait Local {}
+
+// @is "$.index[*][?(@.docs=='Local for bool')].inner.trait.id" $Local
+// @is "$.index[*][?(@.docs=='Local for bool')].inner.for.kind" '"primitive"'
+// @is "$.index[*][?(@.docs=='Local for bool')].inner.for.inner" '"bool"'
+/// Local for bool
+impl Local for bool {}
+
+// @set impl =  "$.index[*][?(@.docs=='Local for bool')].id"
+// @is "$.index[*][?(@.name=='Local')].inner.implementations[*]" $impl
+
+// FIXME(#101695): Test bool's `impls` include "Local for bool"
+// @has "$.index[*][?(@.name=='bool')]"
+#[doc(primitive = "bool")]
+/// Boolean docs
+mod prim_bool {}
diff --git a/src/test/rustdoc-json/impls/local_for_primitive.rs b/src/test/rustdoc-json/impls/local_for_primitive.rs
new file mode 100644
index 000000000000..7702a526fd84
--- /dev/null
+++ b/src/test/rustdoc-json/impls/local_for_primitive.rs
@@ -0,0 +1,7 @@
+// @set local = "$.index[*][?(@.name=='Local')]"
+pub trait Local {}
+
+// @set impl = "$.index[*][?(@.docs=='local for bool')].id"
+// @is "$.index[*][?(@.name=='Local')].inner.implementations[*]" $impl
+/// local for bool
+impl Local for bool {}
diff --git a/src/test/rustdoc-json/intra-doc-links/non_page.rs b/src/test/rustdoc-json/intra-doc-links/non_page.rs
new file mode 100644
index 000000000000..73c5334bb5c6
--- /dev/null
+++ b/src/test/rustdoc-json/intra-doc-links/non_page.rs
@@ -0,0 +1,34 @@
+// Regression test for <https://github.com/rust-lang/rust/issues/101531>,
+// where links where to the item who's HTML page had the item linked to.
+
+//! [`Struct::struct_field`]
+//! [`Enum::Variant`]
+//! [`Trait::AssocType`]
+//! [`Trait::ASSOC_CONST`]
+//! [`Trait::method`]
+
+// @set struct_field = "$.index[*][?(@.name=='struct_field')].id"
+// @set Variant = "$.index[*][?(@.name=='Variant')].id"
+// @set AssocType = "$.index[*][?(@.name=='AssocType')].id"
+// @set ASSOC_CONST = "$.index[*][?(@.name=='ASSOC_CONST')].id"
+// @set method = "$.index[*][?(@.name=='method')].id"
+
+// @is "$.index[*][?(@.name=='non_page')].links['`Struct::struct_field`']" $struct_field
+// @is "$.index[*][?(@.name=='non_page')].links['`Enum::Variant`']" $Variant
+// @is "$.index[*][?(@.name=='non_page')].links['`Trait::AssocType`']" $AssocType
+// @is "$.index[*][?(@.name=='non_page')].links['`Trait::ASSOC_CONST`']" $ASSOC_CONST
+// @is "$.index[*][?(@.name=='non_page')].links['`Trait::method`']" $method
+
+pub struct Struct {
+    pub struct_field: i32,
+}
+
+pub enum Enum {
+    Variant(),
+}
+
+pub trait Trait {
+    const ASSOC_CONST: i32;
+    type AssocType;
+    fn method();
+}
diff --git a/src/test/rustdoc-json/intra-doc-links/user_written.rs b/src/test/rustdoc-json/intra-doc-links/user_written.rs
new file mode 100644
index 000000000000..6871dfea44aa
--- /dev/null
+++ b/src/test/rustdoc-json/intra-doc-links/user_written.rs
@@ -0,0 +1,8 @@
+//! For motivation, see [the reasons](foo#reasons)
+
+/// # Reasons
+/// To test rustdoc json
+pub fn foo() {}
+
+// @set foo = "$.index[*][?(@.name=='foo')].id"
+// @is "$.index[*][?(@.name=='user_written')].links['foo#reasons']" $foo
diff --git a/src/test/rustdoc-json/nested.rs b/src/test/rustdoc-json/nested.rs
index 73ec9392ce94..ee2d2efa960e 100644
--- a/src/test/rustdoc-json/nested.rs
+++ b/src/test/rustdoc-json/nested.rs
@@ -17,7 +17,7 @@ pub mod l1 {
     pub mod l3 {
 
         // @is "$.index[*][?(@.name=='L4')].kind" \"struct\"
-        // @is "$.index[*][?(@.name=='L4')].inner.struct_type" \"unit\"
+        // @is "$.index[*][?(@.name=='L4')].inner.kind" \"unit\"
         // @set l4_id = "$.index[*][?(@.name=='L4')].id"
         // @ismany "$.index[*][?(@.name=='l3')].inner.items[*]" $l4_id
         pub struct L4;
diff --git a/src/test/rustdoc-json/primitives.rs b/src/test/rustdoc-json/primitives.rs
index 491a7b1add48..8024044bc05a 100644
--- a/src/test/rustdoc-json/primitives.rs
+++ b/src/test/rustdoc-json/primitives.rs
@@ -1,22 +1,22 @@
 #![feature(never_type)]
 
-// @has "$.index[*][?(@.name=='PrimNever')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='PrimNever')].inner.type.kind" \"primitive\"
-// @has "$.index[*][?(@.name=='PrimNever')].inner.type.inner" \"never\"
+// @is "$.index[*][?(@.name=='PrimNever')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='PrimNever')].inner.type.kind" \"primitive\"
+// @is "$.index[*][?(@.name=='PrimNever')].inner.type.inner" \"never\"
 pub type PrimNever = !;
 
-// @has "$.index[*][?(@.name=='PrimStr')].inner.type.kind" \"primitive\"
-// @has "$.index[*][?(@.name=='PrimStr')].inner.type.inner" \"str\"
+// @is "$.index[*][?(@.name=='PrimStr')].inner.type.kind" \"primitive\"
+// @is "$.index[*][?(@.name=='PrimStr')].inner.type.inner" \"str\"
 pub type PrimStr = str;
 
-// @has "$.index[*][?(@.name=='PrimBool')].inner.type.kind" \"primitive\"
-// @has "$.index[*][?(@.name=='PrimBool')].inner.type.inner" \"bool\"
+// @is "$.index[*][?(@.name=='PrimBool')].inner.type.kind" \"primitive\"
+// @is "$.index[*][?(@.name=='PrimBool')].inner.type.inner" \"bool\"
 pub type PrimBool = bool;
 
-// @has "$.index[*][?(@.name=='PrimChar')].inner.type.kind" \"primitive\"
-// @has "$.index[*][?(@.name=='PrimChar')].inner.type.inner" \"char\"
+// @is "$.index[*][?(@.name=='PrimChar')].inner.type.kind" \"primitive\"
+// @is "$.index[*][?(@.name=='PrimChar')].inner.type.inner" \"char\"
 pub type PrimChar = char;
 
-// @has "$.index[*][?(@.name=='PrimU8')].inner.type.kind" \"primitive\"
-// @has "$.index[*][?(@.name=='PrimU8')].inner.type.inner" \"u8\"
+// @is "$.index[*][?(@.name=='PrimU8')].inner.type.kind" \"primitive\"
+// @is "$.index[*][?(@.name=='PrimU8')].inner.type.inner" \"u8\"
 pub type PrimU8 = u8;
diff --git a/src/test/rustdoc-json/structs/plain_all_pub.rs b/src/test/rustdoc-json/structs/plain_all_pub.rs
new file mode 100644
index 000000000000..b86ab93c264d
--- /dev/null
+++ b/src/test/rustdoc-json/structs/plain_all_pub.rs
@@ -0,0 +1,11 @@
+pub struct Demo {
+    pub x: i32,
+    pub y: i32,
+}
+
+// @set x = "$.index[*][?(@.name=='x')].id"
+// @set y = "$.index[*][?(@.name=='y')].id"
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[0]" $x
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[1]" $y
+// @count "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[*]" 2
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields_stripped" false
diff --git a/src/test/rustdoc-json/structs/plain_doc_hidden.rs b/src/test/rustdoc-json/structs/plain_doc_hidden.rs
new file mode 100644
index 000000000000..7800b55a481a
--- /dev/null
+++ b/src/test/rustdoc-json/structs/plain_doc_hidden.rs
@@ -0,0 +1,11 @@
+pub struct Demo {
+    pub x: i32,
+    #[doc(hidden)]
+    pub y: i32,
+}
+
+// @set x = "$.index[*][?(@.name=='x')].id"
+// @!has "$.index[*][?(@.name=='y')].id"
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[0]" $x
+// @count "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[*]" 1
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields_stripped" true
diff --git a/src/test/rustdoc-json/structs/plain_empty.rs b/src/test/rustdoc-json/structs/plain_empty.rs
index 2ad9e86096c3..1d01b8bc14a8 100644
--- a/src/test/rustdoc-json/structs/plain_empty.rs
+++ b/src/test/rustdoc-json/structs/plain_empty.rs
@@ -1,6 +1,5 @@
-// @has "$.index[*][?(@.name=='PlainEmpty')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='PlainEmpty')].kind" \"struct\"
-// @has "$.index[*][?(@.name=='PlainEmpty')].inner.struct_type" \"plain\"
-// @has "$.index[*][?(@.name=='PlainEmpty')].inner.fields_stripped" false
-// @has "$.index[*][?(@.name=='PlainEmpty')].inner.fields" []
+// @is "$.index[*][?(@.name=='PlainEmpty')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='PlainEmpty')].kind" \"struct\"
+// @is "$.index[*][?(@.name=='PlainEmpty')].inner.kind.plain.fields_stripped" false
+// @is "$.index[*][?(@.name=='PlainEmpty')].inner.kind.plain.fields" []
 pub struct PlainEmpty {}
diff --git a/src/test/rustdoc-json/structs/plain_pub_priv.rs b/src/test/rustdoc-json/structs/plain_pub_priv.rs
new file mode 100644
index 000000000000..9b771224d974
--- /dev/null
+++ b/src/test/rustdoc-json/structs/plain_pub_priv.rs
@@ -0,0 +1,9 @@
+pub struct Demo {
+    pub x: i32,
+    y: i32,
+}
+
+// @set x = "$.index[*][?(@.name=='x')].id"
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[0]" $x
+// @count "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields[*]" 1
+// @is "$.index[*][?(@.name=='Demo')].inner.kind.plain.fields_stripped" true
diff --git a/src/test/rustdoc-json/structs/tuple.rs b/src/test/rustdoc-json/structs/tuple.rs
index 91fac359422e..6bdb753ee013 100644
--- a/src/test/rustdoc-json/structs/tuple.rs
+++ b/src/test/rustdoc-json/structs/tuple.rs
@@ -1,5 +1,4 @@
-// @has "$.index[*][?(@.name=='Tuple')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='Tuple')].kind" \"struct\"
-// @has "$.index[*][?(@.name=='Tuple')].inner.struct_type" \"tuple\"
-// @has "$.index[*][?(@.name=='Tuple')].inner.fields_stripped" true
+// @is "$.index[*][?(@.name=='Tuple')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='Tuple')].kind" \"struct\"
+// @is "$.index[*][?(@.name=='Tuple')].inner.kind.tuple" '[null, null]'
 pub struct Tuple(u32, String);
diff --git a/src/test/rustdoc-json/structs/tuple_empty.rs b/src/test/rustdoc-json/structs/tuple_empty.rs
new file mode 100644
index 000000000000..0ad6a89547fc
--- /dev/null
+++ b/src/test/rustdoc-json/structs/tuple_empty.rs
@@ -0,0 +1,2 @@
+// @is "$.index[*][?(@.name=='TupleUnit')].inner.kind.tuple" []
+pub struct TupleUnit();
diff --git a/src/test/rustdoc-json/structs/tuple_pub_priv.rs b/src/test/rustdoc-json/structs/tuple_pub_priv.rs
new file mode 100644
index 000000000000..9d5a1d1c8be7
--- /dev/null
+++ b/src/test/rustdoc-json/structs/tuple_pub_priv.rs
@@ -0,0 +1,13 @@
+pub struct Demo(
+    i32,
+    /// field
+    pub i32,
+    #[doc(hidden)] i32,
+);
+
+// @set field = "$.index[*][?(@.docs=='field')].id"
+
+// @is    "$.index[*][?(@.name=='Demo')].inner.kind.tuple[0]" null
+// @is    "$.index[*][?(@.name=='Demo')].inner.kind.tuple[1]" $field
+// @is    "$.index[*][?(@.name=='Demo')].inner.kind.tuple[2]" null
+// @count "$.index[*][?(@.name=='Demo')].inner.kind.tuple[*]" 3
diff --git a/src/test/rustdoc-json/structs/unit.rs b/src/test/rustdoc-json/structs/unit.rs
index 85a515b5e78a..265709717212 100644
--- a/src/test/rustdoc-json/structs/unit.rs
+++ b/src/test/rustdoc-json/structs/unit.rs
@@ -1,5 +1,4 @@
-// @has "$.index[*][?(@.name=='Unit')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='Unit')].kind" \"struct\"
-// @has "$.index[*][?(@.name=='Unit')].inner.struct_type" \"unit\"
-// @has "$.index[*][?(@.name=='Unit')].inner.fields" []
+// @is "$.index[*][?(@.name=='Unit')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='Unit')].kind" \"struct\"
+// @is "$.index[*][?(@.name=='Unit')].inner.kind" \"unit\"
 pub struct Unit;
diff --git a/src/test/rustdoc-json/structs/with_generics.rs b/src/test/rustdoc-json/structs/with_generics.rs
index b0ad1883f8a2..00474800a0e5 100644
--- a/src/test/rustdoc-json/structs/with_generics.rs
+++ b/src/test/rustdoc-json/structs/with_generics.rs
@@ -1,13 +1,13 @@
 use std::collections::HashMap;
 
-// @has "$.index[*][?(@.name=='WithGenerics')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='WithGenerics')].kind" \"struct\"
-// @has "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[0].name" \"T\"
-// @has "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[0].kind.type"
-// @has "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[1].name" \"U\"
-// @has "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[1].kind.type"
-// @has "$.index[*][?(@.name=='WithGenerics')].inner.struct_type" \"plain\"
-// @has "$.index[*][?(@.name=='WithGenerics')].inner.fields_stripped" true
+// @is "$.index[*][?(@.name=='WithGenerics')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='WithGenerics')].kind" \"struct\"
+// @is "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[0].name" \"T\"
+// @is "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[0].kind.type.bounds" []
+// @is "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[1].name" \"U\"
+// @is "$.index[*][?(@.name=='WithGenerics')].inner.generics.params[1].kind.type.bounds" []
+// @is "$.index[*][?(@.name=='WithGenerics')].inner.kind.plain.fields_stripped" true
+// @is "$.index[*][?(@.name=='WithGenerics')].inner.kind.plain.fields" []
 pub struct WithGenerics<T, U> {
     stuff: Vec<T>,
     things: HashMap<U, U>,
diff --git a/src/test/rustdoc-json/structs/with_primitives.rs b/src/test/rustdoc-json/structs/with_primitives.rs
index b74050dde786..9c5a37f3957c 100644
--- a/src/test/rustdoc-json/structs/with_primitives.rs
+++ b/src/test/rustdoc-json/structs/with_primitives.rs
@@ -1,9 +1,9 @@
-// @has "$.index[*][?(@.name=='WithPrimitives')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='WithPrimitives')].kind" \"struct\"
-// @has "$.index[*][?(@.name=='WithPrimitives')].inner.generics.params[0].name" \"\'a\"
-// @has "$.index[*][?(@.name=='WithPrimitives')].inner.generics.params[0].kind.lifetime.outlives" []
-// @has "$.index[*][?(@.name=='WithPrimitives')].inner.struct_type" \"plain\"
-// @has "$.index[*][?(@.name=='WithPrimitives')].inner.fields_stripped" true
+// @is "$.index[*][?(@.name=='WithPrimitives')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='WithPrimitives')].kind" \"struct\"
+// @is "$.index[*][?(@.name=='WithPrimitives')].inner.generics.params[0].name" \"\'a\"
+// @is "$.index[*][?(@.name=='WithPrimitives')].inner.generics.params[0].kind.lifetime.outlives" []
+// @is "$.index[*][?(@.name=='WithPrimitives')].inner.kind.plain.fields_stripped" true
+// @is "$.index[*][?(@.name=='WithPrimitives')].inner.kind.plain.fields" []
 pub struct WithPrimitives<'a> {
     num: u32,
     s: &'a str,
diff --git a/src/test/rustdoc-json/traits/has_body.rs b/src/test/rustdoc-json/traits/has_body.rs
index 4565aba65879..a57cb97d4a6a 100644
--- a/src/test/rustdoc-json/traits/has_body.rs
+++ b/src/test/rustdoc-json/traits/has_body.rs
@@ -1,21 +1,21 @@
 // @has "$.index[*][?(@.name=='Foo')]"
 pub trait Foo {
-    // @has "$.index[*][?(@.name=='no_self')].inner.has_body" false
+    // @is "$.index[*][?(@.name=='no_self')].inner.has_body" false
     fn no_self();
-    // @has "$.index[*][?(@.name=='move_self')].inner.has_body" false
+    // @is "$.index[*][?(@.name=='move_self')].inner.has_body" false
     fn move_self(self);
-    // @has "$.index[*][?(@.name=='ref_self')].inner.has_body" false
+    // @is "$.index[*][?(@.name=='ref_self')].inner.has_body" false
     fn ref_self(&self);
 
-    // @has "$.index[*][?(@.name=='no_self_def')].inner.has_body" true
+    // @is "$.index[*][?(@.name=='no_self_def')].inner.has_body" true
     fn no_self_def() {}
-    // @has "$.index[*][?(@.name=='move_self_def')].inner.has_body" true
+    // @is "$.index[*][?(@.name=='move_self_def')].inner.has_body" true
     fn move_self_def(self) {}
-    // @has "$.index[*][?(@.name=='ref_self_def')].inner.has_body" true
+    // @is "$.index[*][?(@.name=='ref_self_def')].inner.has_body" true
     fn ref_self_def(&self) {}
 }
 
 pub trait Bar: Clone {
-    // @has "$.index[*][?(@.name=='method')].inner.has_body" false
+    // @is "$.index[*][?(@.name=='method')].inner.has_body" false
     fn method(&self, param: usize);
 }
diff --git a/src/test/rustdoc-json/traits/uses_extern_trait.rs b/src/test/rustdoc-json/traits/uses_extern_trait.rs
new file mode 100644
index 000000000000..430dd1543f56
--- /dev/null
+++ b/src/test/rustdoc-json/traits/uses_extern_trait.rs
@@ -0,0 +1,7 @@
+#![no_std]
+pub fn drop_default<T: core::default::Default>(_x: T) {}
+
+// FIXME(adotinthevoid): Theses shouldn't be here
+// @has "$.index[*][?(@.name=='Debug')]"
+// @set Debug_fmt = "$.index[*][?(@.name=='Debug')].inner.items[*]"
+// @has "$.index[*][?(@.name=='fmt')].id" $Debug_fmt
diff --git a/src/test/rustdoc-json/type/dyn.rs b/src/test/rustdoc-json/type/dyn.rs
index 03c6481f80ea..eaf249252e33 100644
--- a/src/test/rustdoc-json/type/dyn.rs
+++ b/src/test/rustdoc-json/type/dyn.rs
@@ -5,9 +5,7 @@ use std::fmt::Debug;
 // @set sync_int_gen = "$.index[*][?(@.name=='SyncIntGen')].id"
 // @set ref_fn       = "$.index[*][?(@.name=='RefFn')].id"
 // @set weird_order  = "$.index[*][?(@.name=='WeirdOrder')].id"
-// @has "$.index[*][?(@.name=='dyn')].inner.items[*]" $sync_int_gen
-// @has "$.index[*][?(@.name=='dyn')].inner.items[*]" $ref_fn
-// @has "$.index[*][?(@.name=='dyn')].inner.items[*]" $weird_order
+// @ismany "$.index[*][?(@.name=='dyn')].inner.items[*]" $sync_int_gen $ref_fn $weird_order
 
 // @is    "$.index[*][?(@.name=='SyncIntGen')].kind" \"typedef\"
 // @is    "$.index[*][?(@.name=='SyncIntGen')].inner.generics" '{"params": [], "where_predicates": []}'
diff --git a/src/test/rustdoc-json/type/extern.rs b/src/test/rustdoc-json/type/extern.rs
new file mode 100644
index 000000000000..d287d5ebec54
--- /dev/null
+++ b/src/test/rustdoc-json/type/extern.rs
@@ -0,0 +1,10 @@
+#![feature(extern_types)]
+
+extern {
+    /// No inner information
+    pub type Foo;
+}
+
+// @is "$.index[*][?(@.docs=='No inner information')].name" '"Foo"'
+// @is "$.index[*][?(@.docs=='No inner information')].kind" '"foreign_type"'
+// @!has "$.index[*][?(@.docs=='No inner information')].inner"
diff --git a/src/test/rustdoc-json/unions/impl.rs b/src/test/rustdoc-json/unions/impl.rs
index 8dfbbfc1baed..4454a69ecd1b 100644
--- a/src/test/rustdoc-json/unions/impl.rs
+++ b/src/test/rustdoc-json/unions/impl.rs
@@ -1,14 +1,14 @@
 #![no_std]
 
-// @has "$.index[*][?(@.name=='Ux')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='Ux')].kind" \"union\"
+// @is "$.index[*][?(@.name=='Ux')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='Ux')].kind" \"union\"
 pub union Ux {
     a: u32,
     b: u64
 }
 
-// @has "$.index[*][?(@.name=='Num')].visibility" \"public\"
-// @has "$.index[*][?(@.name=='Num')].kind" \"trait\"
+// @is "$.index[*][?(@.name=='Num')].visibility" \"public\"
+// @is "$.index[*][?(@.name=='Num')].kind" \"trait\"
 pub trait Num {}
 
 // @count "$.index[*][?(@.name=='Ux')].inner.impls" 1
diff --git a/src/test/rustdoc-json/unions/union.rs b/src/test/rustdoc-json/unions/union.rs
index 5467f68477fc..c9df2b81c4b0 100644
--- a/src/test/rustdoc-json/unions/union.rs
+++ b/src/test/rustdoc-json/unions/union.rs
@@ -1,7 +1,15 @@
 // @has "$.index[*][?(@.name=='Union')].visibility" \"public\"
 // @has "$.index[*][?(@.name=='Union')].kind" \"union\"
 // @!has "$.index[*][?(@.name=='Union')].inner.struct_type"
+// @set Union = "$.index[*][?(@.name=='Union')].id"
 pub union Union {
     int: i32,
     float: f32,
 }
+
+
+// @is "$.index[*][?(@.name=='make_int_union')].inner.decl.output.kind" '"resolved_path"'
+// @is "$.index[*][?(@.name=='make_int_union')].inner.decl.output.inner.id" $Union
+pub fn make_int_union(int: i32) -> Union {
+    Union { int }
+}
diff --git a/src/test/rustdoc-ui/check-fail.rs b/src/test/rustdoc-ui/check-fail.rs
index 2355d6a3d6cb..c5e1759ee2d1 100644
--- a/src/test/rustdoc-ui/check-fail.rs
+++ b/src/test/rustdoc-ui/check-fail.rs
@@ -1,5 +1,6 @@
 // compile-flags: -Z unstable-options --check
 
+#![feature(rustdoc_missing_doc_code_examples)]
 #![deny(missing_docs)]
 #![deny(rustdoc::all)]
 
diff --git a/src/test/rustdoc-ui/check-fail.stderr b/src/test/rustdoc-ui/check-fail.stderr
index 5d46dc720140..217b89d935bf 100644
--- a/src/test/rustdoc-ui/check-fail.stderr
+++ b/src/test/rustdoc-ui/check-fail.stderr
@@ -1,30 +1,30 @@
 error: missing documentation for a function
-  --> $DIR/check-fail.rs:11:1
+  --> $DIR/check-fail.rs:12:1
    |
 LL | pub fn foo() {}
    | ^^^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/check-fail.rs:3:9
+  --> $DIR/check-fail.rs:4:9
    |
 LL | #![deny(missing_docs)]
    |         ^^^^^^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/check-fail.rs:11:1
+  --> $DIR/check-fail.rs:12:1
    |
 LL | pub fn foo() {}
    | ^^^^^^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/check-fail.rs:4:9
+  --> $DIR/check-fail.rs:5:9
    |
 LL | #![deny(rustdoc::all)]
    |         ^^^^^^^^^^^^
    = note: `#[deny(rustdoc::missing_doc_code_examples)]` implied by `#[deny(rustdoc::all)]`
 
 error: unknown attribute `testharness`. Did you mean `test_harness`?
-  --> $DIR/check-fail.rs:6:1
+  --> $DIR/check-fail.rs:7:1
    |
 LL | / //! ```rust,testharness
 LL | |
@@ -36,7 +36,7 @@ LL | | //! ```
    = help: the code block will either not be tested if not marked as a rust one or the code will be wrapped inside a main function
 
 error: unknown attribute `testharness`. Did you mean `test_harness`?
-  --> $DIR/check-fail.rs:15:1
+  --> $DIR/check-fail.rs:16:1
    |
 LL | / /// hello
 LL | |
diff --git a/src/test/rustdoc-ui/check.rs b/src/test/rustdoc-ui/check.rs
index 2b44ba24b442..f70b03361513 100644
--- a/src/test/rustdoc-ui/check.rs
+++ b/src/test/rustdoc-ui/check.rs
@@ -2,9 +2,11 @@
 // compile-flags: -Z unstable-options --check
 // normalize-stderr-test: "nightly|beta|1\.[0-9][0-9]\.[0-9]" -> "$$CHANNEL"
 
-#![warn(missing_docs)]
+#![feature(rustdoc_missing_doc_code_examples)]
 //~^ WARN
 //~^^ WARN
+
+#![warn(missing_docs)]
 #![warn(rustdoc::all)]
 
 pub fn foo() {}
diff --git a/src/test/rustdoc-ui/check.stderr b/src/test/rustdoc-ui/check.stderr
index 06e607fbe55f..78ae65d313a7 100644
--- a/src/test/rustdoc-ui/check.stderr
+++ b/src/test/rustdoc-ui/check.stderr
@@ -1,22 +1,23 @@
 warning: missing documentation for the crate
   --> $DIR/check.rs:5:1
    |
-LL | / #![warn(missing_docs)]
+LL | / #![feature(rustdoc_missing_doc_code_examples)]
 LL | |
 LL | |
-LL | | #![warn(rustdoc::all)]
+LL | |
+...  |
 LL | |
 LL | | pub fn foo() {}
    | |_______________^
    |
 note: the lint level is defined here
-  --> $DIR/check.rs:5:9
+  --> $DIR/check.rs:9:9
    |
 LL | #![warn(missing_docs)]
    |         ^^^^^^^^^^^^
 
 warning: missing documentation for a function
-  --> $DIR/check.rs:10:1
+  --> $DIR/check.rs:12:1
    |
 LL | pub fn foo() {}
    | ^^^^^^^^^^^^
@@ -24,7 +25,7 @@ LL | pub fn foo() {}
 warning: no documentation found for this crate's top-level module
    |
 note: the lint level is defined here
-  --> $DIR/check.rs:8:9
+  --> $DIR/check.rs:10:9
    |
 LL | #![warn(rustdoc::all)]
    |         ^^^^^^^^^^^^
@@ -35,10 +36,11 @@ LL | #![warn(rustdoc::all)]
 warning: missing code example in this documentation
   --> $DIR/check.rs:5:1
    |
-LL | / #![warn(missing_docs)]
+LL | / #![feature(rustdoc_missing_doc_code_examples)]
 LL | |
 LL | |
-LL | | #![warn(rustdoc::all)]
+LL | |
+...  |
 LL | |
 LL | | pub fn foo() {}
    | |_______________^
@@ -46,7 +48,7 @@ LL | | pub fn foo() {}
    = note: `#[warn(rustdoc::missing_doc_code_examples)]` implied by `#[warn(rustdoc::all)]`
 
 warning: missing code example in this documentation
-  --> $DIR/check.rs:10:1
+  --> $DIR/check.rs:12:1
    |
 LL | pub fn foo() {}
    | ^^^^^^^^^^^^^^^
diff --git a/src/test/rustdoc-ui/diagnostic-width.rs b/src/test/rustdoc-ui/diagnostic-width.rs
index 61961d5ec710..290d9db775b7 100644
--- a/src/test/rustdoc-ui/diagnostic-width.rs
+++ b/src/test/rustdoc-ui/diagnostic-width.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Zunstable-options --diagnostic-width=10
+// compile-flags: --diagnostic-width=10
 #![deny(rustdoc::bare_urls)]
 
 /// This is a long line that contains a http://link.com
diff --git a/src/test/rustdoc-ui/doc-without-codeblock.rs b/src/test/rustdoc-ui/doc-without-codeblock.rs
index 315fca195873..86d7c83d3359 100644
--- a/src/test/rustdoc-ui/doc-without-codeblock.rs
+++ b/src/test/rustdoc-ui/doc-without-codeblock.rs
@@ -1,4 +1,5 @@
-#![deny(rustdoc::missing_doc_code_examples)] //~ ERROR missing code example in this documentation
+#![feature(rustdoc_missing_doc_code_examples)] //~ ERROR missing code example in this documentation
+#![deny(rustdoc::missing_doc_code_examples)]
 
 /// Some docs.
 //~^ ERROR missing code example in this documentation
diff --git a/src/test/rustdoc-ui/doc-without-codeblock.stderr b/src/test/rustdoc-ui/doc-without-codeblock.stderr
index 1c138044165f..ebf2a2d54f75 100644
--- a/src/test/rustdoc-ui/doc-without-codeblock.stderr
+++ b/src/test/rustdoc-ui/doc-without-codeblock.stderr
@@ -1,35 +1,35 @@
 error: missing code example in this documentation
   --> $DIR/doc-without-codeblock.rs:1:1
    |
-LL | / #![deny(rustdoc::missing_doc_code_examples)]
+LL | / #![feature(rustdoc_missing_doc_code_examples)]
+LL | | #![deny(rustdoc::missing_doc_code_examples)]
 LL | |
 LL | | /// Some docs.
-LL | |
 ...  |
 LL | |     }
 LL | | }
    | |_^
    |
 note: the lint level is defined here
-  --> $DIR/doc-without-codeblock.rs:1:9
+  --> $DIR/doc-without-codeblock.rs:2:9
    |
 LL | #![deny(rustdoc::missing_doc_code_examples)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/doc-without-codeblock.rs:7:1
+  --> $DIR/doc-without-codeblock.rs:8:1
    |
 LL | /// And then, the princess died.
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/doc-without-codeblock.rs:10:5
+  --> $DIR/doc-without-codeblock.rs:11:5
    |
 LL |     /// Or maybe not because she saved herself!
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/doc-without-codeblock.rs:3:1
+  --> $DIR/doc-without-codeblock.rs:4:1
    |
 LL | /// Some docs.
    | ^^^^^^^^^^^^^^
diff --git a/src/test/rustdoc-ui/feature-gate-rustdoc_missing_doc_code_examples.rs b/src/test/rustdoc-ui/feature-gate-rustdoc_missing_doc_code_examples.rs
new file mode 100644
index 000000000000..daba69868640
--- /dev/null
+++ b/src/test/rustdoc-ui/feature-gate-rustdoc_missing_doc_code_examples.rs
@@ -0,0 +1,10 @@
+#![deny(unknown_lints)]
+//~^ NOTE defined here
+
+#![allow(rustdoc::missing_doc_code_examples)]
+//~^ ERROR unknown lint
+//~| ERROR unknown lint
+//~| NOTE lint is unstable
+//~| NOTE lint is unstable
+//~| NOTE see issue
+//~| NOTE see issue
diff --git a/src/test/rustdoc-ui/feature-gate-rustdoc_missing_doc_code_examples.stderr b/src/test/rustdoc-ui/feature-gate-rustdoc_missing_doc_code_examples.stderr
new file mode 100644
index 000000000000..517e08aa7c97
--- /dev/null
+++ b/src/test/rustdoc-ui/feature-gate-rustdoc_missing_doc_code_examples.stderr
@@ -0,0 +1,29 @@
+error: unknown lint: `rustdoc::missing_doc_code_examples`
+  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:4:1
+   |
+LL | #![allow(rustdoc::missing_doc_code_examples)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:1:9
+   |
+LL | #![deny(unknown_lints)]
+   |         ^^^^^^^^^^^^^
+   = note: the `rustdoc::missing_doc_code_examples` lint is unstable
+   = note: see issue #101730 <https://github.com/rust-lang/rust/issues/101730> for more information
+   = help: add `#![feature(rustdoc_missing_doc_code_examples)]` to the crate attributes to enable
+
+error: unknown lint: `rustdoc::missing_doc_code_examples`
+  --> $DIR/feature-gate-rustdoc_missing_doc_code_examples.rs:4:1
+   |
+LL | #![allow(rustdoc::missing_doc_code_examples)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the `rustdoc::missing_doc_code_examples` lint is unstable
+   = note: see issue #101730 <https://github.com/rust-lang/rust/issues/101730> for more information
+   = help: add `#![feature(rustdoc_missing_doc_code_examples)]` to the crate attributes to enable
+
+error: Compilation failed, aborting rustdoc
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/rustdoc-ui/invalid-html-tags.rs b/src/test/rustdoc-ui/invalid-html-tags.rs
index 0f9d2e4b35d0..317f1fd1d464 100644
--- a/src/test/rustdoc-ui/invalid-html-tags.rs
+++ b/src/test/rustdoc-ui/invalid-html-tags.rs
@@ -114,3 +114,10 @@ pub fn k() {}
 /// Web Components style </unopened-tag>
 //~^ ERROR unopened HTML tag `unopened-tag`
 pub fn m() {}
+
+/// backslashed \<a href="">
+pub fn no_error_1() {}
+
+/// backslashed \<<a href="">
+//~^ ERROR unclosed HTML tag `a`
+pub fn p() {}
diff --git a/src/test/rustdoc-ui/invalid-html-tags.stderr b/src/test/rustdoc-ui/invalid-html-tags.stderr
index 24a455576e80..9c2bfcf2c3dd 100644
--- a/src/test/rustdoc-ui/invalid-html-tags.stderr
+++ b/src/test/rustdoc-ui/invalid-html-tags.stderr
@@ -94,5 +94,11 @@ error: unclosed HTML tag `dashed-tags`
 LL | /// Web Components style <dashed-tags>
    |                          ^^^^^^^^^^^^^
 
-error: aborting due to 15 previous errors
+error: unclosed HTML tag `a`
+  --> $DIR/invalid-html-tags.rs:121:19
+   |
+LL | /// backslashed \<<a href="">
+   |                   ^^
+
+error: aborting due to 16 previous errors
 
diff --git a/src/test/rustdoc-ui/lint-group.rs b/src/test/rustdoc-ui/lint-group.rs
index 61555a6e6861..09aca6d2b274 100644
--- a/src/test/rustdoc-ui/lint-group.rs
+++ b/src/test/rustdoc-ui/lint-group.rs
@@ -1,3 +1,5 @@
+#![feature(rustdoc_missing_doc_code_examples)]
+
 //! Documenting the kinds of lints emitted by rustdoc.
 //!
 //! ```
diff --git a/src/test/rustdoc-ui/lint-group.stderr b/src/test/rustdoc-ui/lint-group.stderr
index e28600160b1f..5336c0445747 100644
--- a/src/test/rustdoc-ui/lint-group.stderr
+++ b/src/test/rustdoc-ui/lint-group.stderr
@@ -1,18 +1,18 @@
 error: missing code example in this documentation
-  --> $DIR/lint-group.rs:16:1
+  --> $DIR/lint-group.rs:18:1
    |
 LL | /// wait, this doesn't have a doctest?
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/lint-group.rs:7:9
+  --> $DIR/lint-group.rs:9:9
    |
 LL | #![deny(rustdoc::all)]
    |         ^^^^^^^^^^^^
    = note: `#[deny(rustdoc::missing_doc_code_examples)]` implied by `#[deny(rustdoc::all)]`
 
 error: documentation test in private item
-  --> $DIR/lint-group.rs:19:1
+  --> $DIR/lint-group.rs:21:1
    |
 LL | / /// wait, this *does* have a doctest?
 LL | | ///
@@ -24,13 +24,13 @@ LL | | /// ```
    = note: `#[deny(rustdoc::private_doc_tests)]` implied by `#[deny(rustdoc::all)]`
 
 error: missing code example in this documentation
-  --> $DIR/lint-group.rs:26:1
+  --> $DIR/lint-group.rs:28:1
    |
 LL | /// <unknown>
    | ^^^^^^^^^^^^^
 
 error: unresolved link to `error`
-  --> $DIR/lint-group.rs:9:29
+  --> $DIR/lint-group.rs:11:29
    |
 LL | /// what up, let's make an [error]
    |                             ^^^^^ no item named `error` in scope
@@ -39,7 +39,7 @@ LL | /// what up, let's make an [error]
    = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
 
 error: unclosed HTML tag `unknown`
-  --> $DIR/lint-group.rs:26:5
+  --> $DIR/lint-group.rs:28:5
    |
 LL | /// <unknown>
    |     ^^^^^^^^^
diff --git a/src/test/rustdoc-ui/lint-missing-doc-code-example.rs b/src/test/rustdoc-ui/lint-missing-doc-code-example.rs
index fac6342cd24b..40f35728d79b 100644
--- a/src/test/rustdoc-ui/lint-missing-doc-code-example.rs
+++ b/src/test/rustdoc-ui/lint-missing-doc-code-example.rs
@@ -1,3 +1,4 @@
+#![feature(rustdoc_missing_doc_code_examples)]
 #![deny(missing_docs)]
 #![deny(rustdoc::missing_doc_code_examples)]
 
diff --git a/src/test/rustdoc-ui/lint-missing-doc-code-example.stderr b/src/test/rustdoc-ui/lint-missing-doc-code-example.stderr
index 9e51ecd2ba01..f9331250154d 100644
--- a/src/test/rustdoc-ui/lint-missing-doc-code-example.stderr
+++ b/src/test/rustdoc-ui/lint-missing-doc-code-example.stderr
@@ -1,35 +1,35 @@
 error: missing code example in this documentation
-  --> $DIR/lint-missing-doc-code-example.rs:19:1
+  --> $DIR/lint-missing-doc-code-example.rs:20:1
    |
 LL | pub mod module1 {
    | ^^^^^^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/lint-missing-doc-code-example.rs:2:9
+  --> $DIR/lint-missing-doc-code-example.rs:3:9
    |
 LL | #![deny(rustdoc::missing_doc_code_examples)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/lint-missing-doc-code-example.rs:37:3
+  --> $DIR/lint-missing-doc-code-example.rs:38:3
    |
 LL |   /// doc
    |   ^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/lint-missing-doc-code-example.rs:49:1
+  --> $DIR/lint-missing-doc-code-example.rs:50:1
    |
 LL | /// Doc
    | ^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/lint-missing-doc-code-example.rs:56:1
+  --> $DIR/lint-missing-doc-code-example.rs:57:1
    |
 LL | /// Doc
    | ^^^^^^^
 
 error: missing code example in this documentation
-  --> $DIR/lint-missing-doc-code-example.rs:63:1
+  --> $DIR/lint-missing-doc-code-example.rs:64:1
    |
 LL | /// Doc
    | ^^^^^^^
diff --git a/src/test/rustdoc-ui/normalize-cycle.rs b/src/test/rustdoc-ui/normalize-cycle.rs
index f48cad373cde..1ed9ac6bc34a 100644
--- a/src/test/rustdoc-ui/normalize-cycle.rs
+++ b/src/test/rustdoc-ui/normalize-cycle.rs
@@ -1,5 +1,6 @@
 // check-pass
-// Regresion test for <https://github.com/rust-lang/rust/issues/79459>.
+// compile-flags: -Znormalize-docs
+// Regression test for <https://github.com/rust-lang/rust/issues/79459>.
 pub trait Query {}
 
 pub trait AsQuery {
diff --git a/src/test/rustdoc-ui/normalize-overflow.rs b/src/test/rustdoc-ui/normalize-overflow.rs
index 0cdcc88e3141..3698fe70e7f7 100644
--- a/src/test/rustdoc-ui/normalize-overflow.rs
+++ b/src/test/rustdoc-ui/normalize-overflow.rs
@@ -1,3 +1,5 @@
 // aux-crate:overflow=overflow.rs
 // check-pass
 // Regression test for <https://github.com/rust-lang/rust/issues/79506>.
+
+extern crate overflow;
diff --git a/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.rs b/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.rs
index 744b3071f1b8..476e3b2d43e4 100644
--- a/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.rs
+++ b/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.rs
@@ -8,6 +8,48 @@ pub struct ConstGeneric;
 // HTML tags cannot contain commas, so no error.
 pub struct MultipleGenerics;
 
+/// This <[u32] as Iterator<Item>> thing!
+//~^ERROR unclosed HTML tag `Item`
+// Some forms of fully-qualified path are simultaneously valid HTML tags
+// with attributes. They produce an error, but no suggestion, because figuring
+// out if this is valid would require parsing the entire path grammar.
+//
+// The important part is that we don't produce any *wrong* suggestions.
+// While several other examples below are added to make sure we don't
+// produce suggestions when given complex paths, this example is the actual
+// reason behind not just using the real path parser. It's ambiguous: there's
+// no way to locally reason out whether that `[u32]` is intended to be a slice
+// or an intra-doc link.
+pub struct FullyQualifiedPathsDoNotCount;
+
+/// This <Vec as IntoIter>::Iter thing!
+//~^ERROR unclosed HTML tag `Vec`
+// Some forms of fully-qualified path are simultaneously valid HTML tags
+// with attributes. They produce an error, but no suggestion, because figuring
+// out if this is valid would require parsing the entire path grammar.
+pub struct FullyQualifiedPathsDoNotCount1;
+
+/// This Vec<Vec as IntoIter>::Iter thing!
+//~^ERROR unclosed HTML tag `Vec`
+// Some forms of fully-qualified path are simultaneously valid HTML tags
+// with attributes. They produce an error, but no suggestion, because figuring
+// out if this is valid would require parsing the entire path grammar.
+pub struct FullyQualifiedPathsDoNotCount2;
+
+/// This Vec<Vec as IntoIter> thing!
+//~^ERROR unclosed HTML tag `Vec`
+// Some forms of fully-qualified path are simultaneously valid HTML tags
+// with attributes. They produce an error, but no suggestion, because figuring
+// out if this is valid would require parsing the entire path grammar.
+pub struct FullyQualifiedPathsDoNotCount3;
+
+/// This Vec<Vec<i32> as IntoIter> thing!
+//~^ERROR unclosed HTML tag `i32`
+// Some forms of fully-qualified path are simultaneously valid HTML tags
+// with attributes. They produce an error, but no suggestion, because figuring
+// out if this is valid would require parsing the entire path grammar.
+pub struct FullyQualifiedPathsDoNotCount4;
+
 /// This Vec<i32 class="test"> thing!
 //~^ERROR unclosed HTML tag `i32`
 // HTML attributes shouldn't be treated as Rust syntax, so no suggestions.
diff --git a/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.stderr b/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.stderr
index 832b8b2cac79..3856a251321b 100644
--- a/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.stderr
+++ b/src/test/rustdoc-ui/suggestions/html-as-generics-no-suggestions.stderr
@@ -1,8 +1,8 @@
-error: unclosed HTML tag `i32`
-  --> $DIR/html-as-generics-no-suggestions.rs:11:13
+error: unclosed HTML tag `Item`
+  --> $DIR/html-as-generics-no-suggestions.rs:11:28
    |
-LL | /// This Vec<i32 class="test"> thing!
-   |             ^^^^
+LL | /// This <[u32] as Iterator<Item>> thing!
+   |                            ^^^^^^
    |
 note: the lint level is defined here
   --> $DIR/html-as-generics-no-suggestions.rs:1:9
@@ -10,29 +10,59 @@ note: the lint level is defined here
 LL | #![deny(rustdoc::invalid_html_tags)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error: unclosed HTML tag `Vec`
+  --> $DIR/html-as-generics-no-suggestions.rs:25:10
+   |
+LL | /// This <Vec as IntoIter>::Iter thing!
+   |          ^^^^
+
+error: unclosed HTML tag `Vec`
+  --> $DIR/html-as-generics-no-suggestions.rs:32:13
+   |
+LL | /// This Vec<Vec as IntoIter>::Iter thing!
+   |             ^^^^
+
+error: unclosed HTML tag `Vec`
+  --> $DIR/html-as-generics-no-suggestions.rs:39:13
+   |
+LL | /// This Vec<Vec as IntoIter> thing!
+   |             ^^^^
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics-no-suggestions.rs:46:17
+   |
+LL | /// This Vec<Vec<i32> as IntoIter> thing!
+   |                 ^^^^^
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics-no-suggestions.rs:53:13
+   |
+LL | /// This Vec<i32 class="test"> thing!
+   |             ^^^^
+
 error: unopened HTML tag `i32`
-  --> $DIR/html-as-generics-no-suggestions.rs:20:13
+  --> $DIR/html-as-generics-no-suggestions.rs:62:13
    |
 LL | /// This Vec</i32> thing!
    |             ^^^^^^
 
 error: unclosed HTML tag `i32`
-  --> $DIR/html-as-generics-no-suggestions.rs:25:13
+  --> $DIR/html-as-generics-no-suggestions.rs:67:13
    |
 LL | /// This 123<i32> thing!
    |             ^^^^^
 
 error: unclosed HTML tag `i32`
-  --> $DIR/html-as-generics-no-suggestions.rs:30:14
+  --> $DIR/html-as-generics-no-suggestions.rs:72:14
    |
 LL | /// This Vec:<i32> thing!
    |              ^^^^^
 
 error: unclosed HTML tag `i32`
-  --> $DIR/html-as-generics-no-suggestions.rs:35:39
+  --> $DIR/html-as-generics-no-suggestions.rs:77:39
    |
 LL | /// This [link](https://rust-lang.org)<i32> thing!
    |                                       ^^^^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 10 previous errors
 
diff --git a/src/test/rustdoc-ui/suggestions/html-as-generics.fixed b/src/test/rustdoc-ui/suggestions/html-as-generics.fixed
index c0a0de24c526..003542d3855a 100644
--- a/src/test/rustdoc-ui/suggestions/html-as-generics.fixed
+++ b/src/test/rustdoc-ui/suggestions/html-as-generics.fixed
@@ -30,3 +30,53 @@ pub struct BareTurbofish;
 //~^ERROR unclosed HTML tag `i32`
 //~|HELP try marking as source
 pub struct Nested;
+
+/// Nested generics `Vec<Vec<u32>>`
+//~^ ERROR unclosed HTML tag `u32`
+//~|HELP try marking as source
+pub struct NestedGenerics;
+
+/// Generics with path `Vec<i32>::Iter`
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct GenericsWithPath;
+
+/// Generics with path `<Vec<i32>>::Iter`
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPath;
+
+/// Generics with path `Vec<Vec<i32>>::Iter`
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPath2;
+
+/// Generics with bump `<Vec<i32>>`s
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithBump;
+
+/// Generics with bump `Vec<Vec<i32>>`s
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithBump2;
+
+/// Generics with punct `<Vec<i32>>`!
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPunct;
+
+/// Generics with punct `Vec<Vec<i32>>`!
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPunct2;
+
+/// This [`Vec<i32>`] thing!
+//~^ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct IntraDocLink;
+
+/// This [`Vec::<i32>`] thing!
+//~^ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct IntraDocLinkTurbofish;
diff --git a/src/test/rustdoc-ui/suggestions/html-as-generics.rs b/src/test/rustdoc-ui/suggestions/html-as-generics.rs
index 0b6009b0e59c..4254a660b19e 100644
--- a/src/test/rustdoc-ui/suggestions/html-as-generics.rs
+++ b/src/test/rustdoc-ui/suggestions/html-as-generics.rs
@@ -30,3 +30,53 @@ pub struct BareTurbofish;
 //~^ERROR unclosed HTML tag `i32`
 //~|HELP try marking as source
 pub struct Nested;
+
+/// Nested generics Vec<Vec<u32>>
+//~^ ERROR unclosed HTML tag `u32`
+//~|HELP try marking as source
+pub struct NestedGenerics;
+
+/// Generics with path Vec<i32>::Iter
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct GenericsWithPath;
+
+/// Generics with path <Vec<i32>>::Iter
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPath;
+
+/// Generics with path Vec<Vec<i32>>::Iter
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPath2;
+
+/// Generics with bump <Vec<i32>>s
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithBump;
+
+/// Generics with bump Vec<Vec<i32>>s
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithBump2;
+
+/// Generics with punct <Vec<i32>>!
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPunct;
+
+/// Generics with punct Vec<Vec<i32>>!
+//~^ ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct NestedGenericsWithPunct2;
+
+/// This [Vec<i32>] thing!
+//~^ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct IntraDocLink;
+
+/// This [Vec::<i32>] thing!
+//~^ERROR unclosed HTML tag `i32`
+//~|HELP try marking as source
+pub struct IntraDocLinkTurbofish;
diff --git a/src/test/rustdoc-ui/suggestions/html-as-generics.stderr b/src/test/rustdoc-ui/suggestions/html-as-generics.stderr
index df54b71264eb..481278bdaf9a 100644
--- a/src/test/rustdoc-ui/suggestions/html-as-generics.stderr
+++ b/src/test/rustdoc-ui/suggestions/html-as-generics.stderr
@@ -69,5 +69,115 @@ help: try marking as source code
 LL | /// This <span>`Vec::<i32>`</span> thing!
    |                +          +
 
-error: aborting due to 6 previous errors
+error: unclosed HTML tag `u32`
+  --> $DIR/html-as-generics.rs:34:28
+   |
+LL | /// Nested generics Vec<Vec<u32>>
+   |                            ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Nested generics `Vec<Vec<u32>>`
+   |                     +             +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:39:27
+   |
+LL | /// Generics with path Vec<i32>::Iter
+   |                           ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with path `Vec<i32>::Iter`
+   |                        +              +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:44:28
+   |
+LL | /// Generics with path <Vec<i32>>::Iter
+   |                            ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with path `<Vec<i32>>::Iter`
+   |                        +                +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:49:31
+   |
+LL | /// Generics with path Vec<Vec<i32>>::Iter
+   |                               ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with path `Vec<Vec<i32>>::Iter`
+   |                        +                   +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:54:28
+   |
+LL | /// Generics with bump <Vec<i32>>s
+   |                            ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with bump `<Vec<i32>>`s
+   |                        +          +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:59:31
+   |
+LL | /// Generics with bump Vec<Vec<i32>>s
+   |                               ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with bump `Vec<Vec<i32>>`s
+   |                        +             +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:64:29
+   |
+LL | /// Generics with punct <Vec<i32>>!
+   |                             ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with punct `<Vec<i32>>`!
+   |                         +          +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:69:32
+   |
+LL | /// Generics with punct Vec<Vec<i32>>!
+   |                                ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// Generics with punct `Vec<Vec<i32>>`!
+   |                         +             +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:74:14
+   |
+LL | /// This [Vec<i32>] thing!
+   |              ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// This [`Vec<i32>`] thing!
+   |           +        +
+
+error: unclosed HTML tag `i32`
+  --> $DIR/html-as-generics.rs:79:16
+   |
+LL | /// This [Vec::<i32>] thing!
+   |                ^^^^^
+   |
+help: try marking as source code
+   |
+LL | /// This [`Vec::<i32>`] thing!
+   |           +          +
+
+error: aborting due to 16 previous errors
 
diff --git a/src/test/rustdoc-ui/z-help.stdout b/src/test/rustdoc-ui/z-help.stdout
index 236469ce9797..25d5c6e4ad2b 100644
--- a/src/test/rustdoc-ui/z-help.stdout
+++ b/src/test/rustdoc-ui/z-help.stdout
@@ -54,6 +54,7 @@
     -Z                        incremental-info=val -- print high-level information about incremental reuse (or the lack thereof) (default: no)
     -Z              incremental-relative-spans=val -- hash spans relative to their parent item for incr. comp. (default: no)
     -Z                  incremental-verify-ich=val -- verify incr. comp. hashes of green query instances (default: no)
+    -Z                             inline-llvm=val -- enable LLVM inlining (default: yes)
     -Z                              inline-mir=val -- enable MIR inlining (default: no)
     -Z                    inline-mir-threshold=val -- a default MIR inlining threshold (default: 50)
     -Z               inline-mir-hint-threshold=val -- inlining threshold for functions with inline hint (default: 100)
@@ -81,7 +82,6 @@
     -Z                           mir-opt-level=val -- MIR optimization level (0-4; default: 1 in non optimized builds and 2 in optimized builds)
     -Z                         move-size-limit=val -- the size at which the `large_assignments` lint starts to be emitted
     -Z                         mutable-noalias=val -- emit noalias metadata for mutable references (default: yes)
-    -Z                   new-llvm-pass-manager=val -- use new LLVM pass manager (default: no)
     -Z                               nll-facts=val -- dump facts from NLL analysis into side files (default: no)
     -Z                           nll-facts-dir=val -- the directory the NLL facts are dumped into (default: `nll-facts`)
     -Z                             no-analysis=val -- parse and expand the source, but run no analysis
@@ -97,6 +97,7 @@
     -Z                                     oom=val -- panic strategy for out-of-memory handling
     -Z                  osx-rpath-install-name=val -- pass `-install_name @rpath/...` to the macOS linker (default: no)
     -Z                        diagnostic-width=val -- set the current output width for diagnostic truncation
+    -Z                     packed-bundled-libs=val -- change rlib format to store native libraries as archives
     -Z                       panic-abort-tests=val -- support compiling tests with panic=abort (default: no)
     -Z                           panic-in-drop=val -- panic strategy for panics in drops
     -Z                              parse-only=val -- parse only; do not compile, assemble, or link (default: no)
diff --git a/src/test/rustdoc/anonymous-lifetime.rs b/src/test/rustdoc/anonymous-lifetime.rs
index f5a7d225847c..390ed5a1f938 100644
--- a/src/test/rustdoc/anonymous-lifetime.rs
+++ b/src/test/rustdoc/anonymous-lifetime.rs
@@ -12,7 +12,7 @@ pub trait Stream {
 }
 
 // @has 'foo/trait.Stream.html'
-// @has - '//*[@class="code-header in-band"]' 'impl<S: ?Sized + Stream + Unpin> Stream for &mut S'
+// @has - '//*[@class="code-header"]' 'impl<S: ?Sized + Stream + Unpin> Stream for &mut S'
 impl<S: ?Sized + Stream + Unpin> Stream for &mut S {
     type Item = S::Item;
 
diff --git a/src/test/rustdoc/assoc-consts.rs b/src/test/rustdoc/assoc-consts.rs
index 97b7739b4c97..a3e10ee5555a 100644
--- a/src/test/rustdoc/assoc-consts.rs
+++ b/src/test/rustdoc/assoc-consts.rs
@@ -13,7 +13,7 @@ pub trait Foo {
 pub struct Bar;
 
 impl Foo for Bar {
-    // @has assoc_consts/struct.Bar.html '//h3[@class="code-header in-band"]' 'impl Foo for Bar'
+    // @has assoc_consts/struct.Bar.html '//h3[@class="code-header"]' 'impl Foo for Bar'
     // @has - '//*[@id="associatedconstant.FOO"]' 'const FOO: usize'
     const FOO: usize = 12;
     // @has - '//*[@id="associatedconstant.FOO_NO_DEFAULT"]' 'const FOO_NO_DEFAULT: bool'
@@ -81,7 +81,7 @@ pub trait Qux {
     const QUX_DEFAULT2: u32 = 3;
 }
 
-// @has assoc_consts/struct.Bar.html '//h3[@class="code-header in-band"]' 'impl Qux for Bar'
+// @has assoc_consts/struct.Bar.html '//h3[@class="code-header"]' 'impl Qux for Bar'
 impl Qux for Bar {
     // @has - '//*[@id="associatedconstant.QUX0"]' 'const QUX0: u8'
     // @has - '//*[@class="docblock"]' "Docs for QUX0 in trait."
diff --git a/src/test/rustdoc/attribute-rendering.rs b/src/test/rustdoc/attribute-rendering.rs
index 6777871846e2..36e10923c853 100644
--- a/src/test/rustdoc/attribute-rendering.rs
+++ b/src/test/rustdoc/attribute-rendering.rs
@@ -1,7 +1,7 @@
 #![crate_name = "foo"]
 
 // @has 'foo/fn.f.html'
-// @has - //*[@'class="docblock item-decl"]' '#[export_name = "f"] pub fn f()'
+// @has - //*[@'class="item-decl"]' '#[export_name = "f"] pub fn f()'
 #[export_name = "\
 f"]
 pub fn f() {}
diff --git a/src/test/rustdoc/attributes.rs b/src/test/rustdoc/attributes.rs
index 1c7f4b724189..a36dadced87d 100644
--- a/src/test/rustdoc/attributes.rs
+++ b/src/test/rustdoc/attributes.rs
@@ -8,6 +8,6 @@ pub extern "C" fn f() {}
 #[export_name = "bar"]
 pub extern "C" fn g() {}
 
-// @has foo/struct.Repr.html '//*[@class="docblock item-decl"]' '#[repr(C, align(8))]'
+// @has foo/struct.Repr.html '//*[@class="item-decl"]' '#[repr(C, align(8))]'
 #[repr(C, align(8))]
 pub struct Repr;
diff --git a/src/test/rustdoc/blanket-reexport-item.rs b/src/test/rustdoc/blanket-reexport-item.rs
index 676d656dabf4..437f0001fcfc 100644
--- a/src/test/rustdoc/blanket-reexport-item.rs
+++ b/src/test/rustdoc/blanket-reexport-item.rs
@@ -1,6 +1,6 @@
 #![crate_name = "foo"]
 
-// @has foo/struct.S.html '//*[@id="impl-Into%3CU%3E-for-S"]//h3[@class="code-header in-band"]' 'impl<T, U> Into<U> for T'
+// @has foo/struct.S.html '//*[@id="impl-Into%3CU%3E-for-S"]//h3[@class="code-header"]' 'impl<T, U> Into<U> for T'
 pub struct S2 {}
 mod m {
     pub struct S {}
diff --git a/src/test/rustdoc/check-source-code-urls-to-def-std.rs b/src/test/rustdoc/check-source-code-urls-to-def-std.rs
index 3396b234a77b..e12d8445f4fa 100644
--- a/src/test/rustdoc/check-source-code-urls-to-def-std.rs
+++ b/src/test/rustdoc/check-source-code-urls-to-def-std.rs
@@ -9,7 +9,7 @@ fn babar() {}
 // @has - '//a[@href="{{channel}}/std/primitive.u32.html"]' 'u32'
 // @has - '//a[@href="{{channel}}/std/primitive.str.html"]' 'str'
 // @has - '//a[@href="{{channel}}/std/primitive.bool.html"]' 'bool'
-// @has - '//a[@href="../../src/foo/check-source-code-urls-to-def-std.rs.html#7"]' 'babar'
+// @has - '//a[@href="#7"]' 'babar'
 pub fn foo(a: u32, b: &str, c: String) {
     let x = 12;
     let y: bool = true;
@@ -31,12 +31,12 @@ macro_rules! data {
 pub fn another_foo() {
     // This is known limitation: if the macro doesn't generate anything, the visitor
     // can't find any item or anything that could tell us that it comes from expansion.
-    // @!has - '//a[@href="../../src/foo/check-source-code-urls-to-def-std.rs.html#19"]' 'yolo!'
+    // @!has - '//a[@href="#19"]' 'yolo!'
     yolo!();
     // @has - '//a[@href="{{channel}}/std/macro.eprintln.html"]' 'eprintln!'
     eprintln!();
-    // @has - '//a[@href="../../src/foo/check-source-code-urls-to-def-std.rs.html#27-29"]' 'data!'
+    // @has - '//a[@href="#27-29"]' 'data!'
     let x = data!(4);
-    // @has - '//a[@href="../../src/foo/check-source-code-urls-to-def-std.rs.html#23-25"]' 'bar!'
+    // @has - '//a[@href="#23-25"]' 'bar!'
     bar!(x);
 }
diff --git a/src/test/rustdoc/check-source-code-urls-to-def.rs b/src/test/rustdoc/check-source-code-urls-to-def.rs
index ec44e1bc65c9..d00a3e355199 100644
--- a/src/test/rustdoc/check-source-code-urls-to-def.rs
+++ b/src/test/rustdoc/check-source-code-urls-to-def.rs
@@ -10,14 +10,14 @@ extern crate source_code;
 
 // @has 'src/foo/check-source-code-urls-to-def.rs.html'
 
-// @has - '//a[@href="../../src/foo/auxiliary/source-code-bar.rs.html#1-17"]' 'bar'
+// @has - '//a[@href="auxiliary/source-code-bar.rs.html#1-17"]' 'bar'
 #[path = "auxiliary/source-code-bar.rs"]
 pub mod bar;
 
-// @count - '//a[@href="../../src/foo/auxiliary/source-code-bar.rs.html#5"]' 4
+// @count - '//a[@href="auxiliary/source-code-bar.rs.html#5"]' 4
 use bar::Bar;
-// @has - '//a[@href="../../src/foo/auxiliary/source-code-bar.rs.html#13"]' 'self'
-// @has - '//a[@href="../../src/foo/auxiliary/source-code-bar.rs.html#14"]' 'Trait'
+// @has - '//a[@href="auxiliary/source-code-bar.rs.html#13"]' 'self'
+// @has - '//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'Trait'
 use bar::sub::{self, Trait};
 
 pub struct Foo;
@@ -31,26 +31,26 @@ fn babar() {}
 // @has - '//a/@href' '/struct.String.html'
 // @has - '//a/@href' '/primitive.u32.html'
 // @has - '//a/@href' '/primitive.str.html'
-// @count - '//a[@href="../../src/foo/check-source-code-urls-to-def.rs.html#23"]' 5
+// @count - '//a[@href="#23"]' 5
 // @has - '//a[@href="../../source_code/struct.SourceCode.html"]' 'source_code::SourceCode'
 pub fn foo(a: u32, b: &str, c: String, d: Foo, e: bar::Bar, f: source_code::SourceCode) {
     let x = 12;
     let y: Foo = Foo;
     let z: Bar = bar::Bar { field: Foo };
     babar();
-    // @has - '//a[@href="../../src/foo/check-source-code-urls-to-def.rs.html#26"]' 'hello'
+    // @has - '//a[@href="#26"]' 'hello'
     y.hello();
 }
 
-// @has - '//a[@href="../../src/foo/auxiliary/source-code-bar.rs.html#14"]' 'bar::sub::Trait'
-// @has - '//a[@href="../../src/foo/auxiliary/source-code-bar.rs.html#14"]' 'Trait'
+// @has - '//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'bar::sub::Trait'
+// @has - '//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'Trait'
 pub fn foo2<T: bar::sub::Trait, V: Trait>(t: &T, v: &V, b: bool) {}
 
 pub trait AnotherTrait {}
 pub trait WhyNot {}
 
-// @has - '//a[@href="../../src/foo/check-source-code-urls-to-def.rs.html#49"]' 'AnotherTrait'
-// @has - '//a[@href="../../src/foo/check-source-code-urls-to-def.rs.html#50"]' 'WhyNot'
+// @has - '//a[@href="#49"]' 'AnotherTrait'
+// @has - '//a[@href="#50"]' 'WhyNot'
 pub fn foo3<T, V>(t: &T, v: &V)
 where
     T: AnotherTrait,
@@ -59,7 +59,7 @@ where
 
 pub trait AnotherTrait2 {}
 
-// @has - '//a[@href="../../src/foo/check-source-code-urls-to-def.rs.html#60"]' 'AnotherTrait2'
+// @has - '//a[@href="#60"]' 'AnotherTrait2'
 pub fn foo4() {
     let x: Vec<AnotherTrait2> = Vec::new();
 }
diff --git a/src/test/rustdoc/codeblock-title.rs b/src/test/rustdoc/codeblock-title.rs
index 140c5b3a6720..b9b0b0d1abf9 100644
--- a/src/test/rustdoc/codeblock-title.rs
+++ b/src/test/rustdoc/codeblock-title.rs
@@ -1,8 +1,8 @@
 #![crate_name = "foo"]
 
-// @has foo/fn.bar.html '//*[@class="tooltip compile_fail"]' "ⓘ"
-// @has foo/fn.bar.html '//*[@class="tooltip ignore"]' "ⓘ"
-// @has foo/fn.bar.html '//*[@class="tooltip should_panic"]' "ⓘ"
+// @has foo/fn.bar.html '//*[@class="example-wrap compile_fail"]/*[@class="tooltip"]' "ⓘ"
+// @has foo/fn.bar.html '//*[@class="example-wrap ignore"]/*[@class="tooltip"]' "ⓘ"
+// @has foo/fn.bar.html '//*[@class="example-wrap should_panic"]/*[@class="tooltip"]' "ⓘ"
 // @has foo/fn.bar.html '//*[@data-edition="2018"]' "ⓘ"
 
 /// foo
diff --git a/src/test/rustdoc/const-generics/add-impl.rs b/src/test/rustdoc/const-generics/add-impl.rs
index 591139523456..6cbae9abebb7 100644
--- a/src/test/rustdoc/const-generics/add-impl.rs
+++ b/src/test/rustdoc/const-generics/add-impl.rs
@@ -7,7 +7,7 @@ pub struct Simd<T, const WIDTH: usize> {
     inner: T,
 }
 
-// @has foo/struct.Simd.html '//div[@id="trait-implementations-list"]//h3[@class="code-header in-band"]' 'impl Add<Simd<u8, 16>> for Simd<u8, 16>'
+// @has foo/struct.Simd.html '//div[@id="trait-implementations-list"]//h3[@class="code-header"]' 'impl Add<Simd<u8, 16>> for Simd<u8, 16>'
 impl Add for Simd<u8, 16> {
     type Output = Self;
 
diff --git a/src/test/rustdoc/const-generics/const-generics-docs.rs b/src/test/rustdoc/const-generics/const-generics-docs.rs
index 352a8e646bb4..5bf76e3c4690 100644
--- a/src/test/rustdoc/const-generics/const-generics-docs.rs
+++ b/src/test/rustdoc/const-generics/const-generics-docs.rs
@@ -19,10 +19,10 @@ pub use extern_crate::WTrait;
 
 // @has foo/trait.Trait.html '//pre[@class="rust trait"]' \
 //      'pub trait Trait<const N: usize>'
-// @has - '//*[@id="impl-Trait%3C1%3E-for-u8"]//h3[@class="code-header in-band"]' 'impl Trait<1> for u8'
-// @has - '//*[@id="impl-Trait%3C2%3E-for-u8"]//h3[@class="code-header in-band"]' 'impl Trait<2> for u8'
-// @has - '//*[@id="impl-Trait%3C{1%20+%202}%3E-for-u8"]//h3[@class="code-header in-band"]' 'impl Trait<{1 + 2}> for u8'
-// @has - '//*[@id="impl-Trait%3CN%3E-for-%5Bu8%3B%20N%5D"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="impl-Trait%3C1%3E-for-u8"]//h3[@class="code-header"]' 'impl Trait<1> for u8'
+// @has - '//*[@id="impl-Trait%3C2%3E-for-u8"]//h3[@class="code-header"]' 'impl Trait<2> for u8'
+// @has - '//*[@id="impl-Trait%3C{1%20+%202}%3E-for-u8"]//h3[@class="code-header"]' 'impl Trait<{1 + 2}> for u8'
+// @has - '//*[@id="impl-Trait%3CN%3E-for-%5Bu8%3B%20N%5D"]//h3[@class="code-header"]' \
 //      'impl<const N: usize> Trait<N> for [u8; N]'
 pub trait Trait<const N: usize> {}
 impl Trait<1> for u8 {}
@@ -31,12 +31,12 @@ impl Trait<{1 + 2}> for u8 {}
 impl<const N: usize> Trait<N> for [u8; N] {}
 
 // @has foo/struct.Foo.html '//pre[@class="rust struct"]' \
-//      'pub struct Foo<const N: usize> where u8: Trait<N>'
+//      'pub struct Foo<const N: usize>where u8: Trait<N>'
 pub struct Foo<const N: usize> where u8: Trait<N>;
 // @has foo/struct.Bar.html '//pre[@class="rust struct"]' 'pub struct Bar<T, const N: usize>(_)'
 pub struct Bar<T, const N: usize>([T; N]);
 
-// @has foo/struct.Foo.html '//*[@id="impl-Foo%3CM%3E"]/h3[@class="code-header in-band"]' 'impl<const M: usize> Foo<M> where u8: Trait<M>'
+// @has foo/struct.Foo.html '//*[@id="impl-Foo%3CM%3E"]/h3[@class="code-header"]' 'impl<const M: usize> Foo<M>where u8: Trait<M>'
 impl<const M: usize> Foo<M> where u8: Trait<M> {
     // @has - '//*[@id="associatedconstant.FOO_ASSOC"]' 'pub const FOO_ASSOC: usize'
     pub const FOO_ASSOC: usize = M + 13;
@@ -47,17 +47,17 @@ impl<const M: usize> Foo<M> where u8: Trait<M> {
     }
 }
 
-// @has foo/struct.Bar.html '//*[@id="impl-Bar%3Cu8%2C%20M%3E"]/h3[@class="code-header in-band"]' 'impl<const M: usize> Bar<u8, M>'
+// @has foo/struct.Bar.html '//*[@id="impl-Bar%3Cu8%2C%20M%3E"]/h3[@class="code-header"]' 'impl<const M: usize> Bar<u8, M>'
 impl<const M: usize> Bar<u8, M> {
     // @has - '//*[@id="method.hey"]' \
-    //      'pub fn hey<const N: usize>(&self) -> Foo<N> where u8: Trait<N>'
+    //      'pub fn hey<const N: usize>(&self) -> Foo<N>where u8: Trait<N>'
     pub fn hey<const N: usize>(&self) -> Foo<N> where u8: Trait<N> {
         Foo
     }
 }
 
 // @has foo/fn.test.html '//pre[@class="rust fn"]' \
-//      'pub fn test<const N: usize>() -> impl Trait<N> where u8: Trait<N>'
+//      'pub fn test<const N: usize>() -> impl Trait<N>where u8: Trait<N>'
 pub fn test<const N: usize>() -> impl Trait<N> where u8: Trait<N> {
     2u8
 }
diff --git a/src/test/rustdoc/const-generics/const-impl.rs b/src/test/rustdoc/const-generics/const-impl.rs
index f1181d54ac87..75ee84279be3 100644
--- a/src/test/rustdoc/const-generics/const-impl.rs
+++ b/src/test/rustdoc/const-generics/const-impl.rs
@@ -9,20 +9,20 @@ pub enum Order {
 }
 
 // @has foo/struct.VSet.html '//pre[@class="rust struct"]' 'pub struct VSet<T, const ORDER: Order>'
-// @has foo/struct.VSet.html '//*[@id="impl-Send-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header in-band"]' 'impl<T, const ORDER: Order> Send for VSet<T, ORDER>'
-// @has foo/struct.VSet.html '//*[@id="impl-Sync-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header in-band"]' 'impl<T, const ORDER: Order> Sync for VSet<T, ORDER>'
+// @has foo/struct.VSet.html '//*[@id="impl-Send-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header"]' 'impl<T, const ORDER: Order> Send for VSet<T, ORDER>'
+// @has foo/struct.VSet.html '//*[@id="impl-Sync-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header"]' 'impl<T, const ORDER: Order> Sync for VSet<T, ORDER>'
 pub struct VSet<T, const ORDER: Order> {
     inner: Vec<T>,
 }
 
-// @has foo/struct.VSet.html '//*[@id="impl-VSet%3CT%2C%20{%20Order%3A%3ASorted%20}%3E"]/h3[@class="code-header in-band"]' 'impl<T> VSet<T, { Order::Sorted }>'
+// @has foo/struct.VSet.html '//*[@id="impl-VSet%3CT%2C%20{%20Order%3A%3ASorted%20}%3E"]/h3[@class="code-header"]' 'impl<T> VSet<T, { Order::Sorted }>'
 impl<T> VSet<T, { Order::Sorted }> {
     pub fn new() -> Self {
         Self { inner: Vec::new() }
     }
 }
 
-// @has foo/struct.VSet.html '//*[@id="impl-VSet%3CT%2C%20{%20Order%3A%3AUnsorted%20}%3E"]/h3[@class="code-header in-band"]' 'impl<T> VSet<T, { Order::Unsorted }>'
+// @has foo/struct.VSet.html '//*[@id="impl-VSet%3CT%2C%20{%20Order%3A%3AUnsorted%20}%3E"]/h3[@class="code-header"]' 'impl<T> VSet<T, { Order::Unsorted }>'
 impl<T> VSet<T, { Order::Unsorted }> {
     pub fn new() -> Self {
         Self { inner: Vec::new() }
@@ -31,7 +31,7 @@ impl<T> VSet<T, { Order::Unsorted }> {
 
 pub struct Escape<const S: &'static str>;
 
-// @has foo/struct.Escape.html '//*[@id="impl-Escape%3Cr#%22%3Cscript%3Ealert(%22Escape%22)%3B%3C/script%3E%22#%3E"]/h3[@class="code-header in-band"]' 'impl Escape<r#"<script>alert("Escape");</script>"#>'
+// @has foo/struct.Escape.html '//*[@id="impl-Escape%3Cr#%22%3Cscript%3Ealert(%22Escape%22)%3B%3C/script%3E%22#%3E"]/h3[@class="code-header"]' 'impl Escape<r#"<script>alert("Escape");</script>"#>'
 impl Escape<r#"<script>alert("Escape");</script>"#> {
     pub fn f() {}
 }
diff --git a/src/test/rustdoc/const-generics/lazy_normalization_consts/const-equate-pred.rs b/src/test/rustdoc/const-generics/lazy_normalization_consts/const-equate-pred.rs
index 4eac8e31e452..310e89a35c4a 100644
--- a/src/test/rustdoc/const-generics/lazy_normalization_consts/const-equate-pred.rs
+++ b/src/test/rustdoc/const-generics/lazy_normalization_consts/const-equate-pred.rs
@@ -12,7 +12,7 @@ pub struct Hasher<T> {
 unsafe impl<T: Default> Send for Hasher<T> {}
 
 // @has foo/struct.Foo.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Send for Foo'
+// @has - '//h3[@class="code-header"]' 'impl Send for Foo'
 pub struct Foo {
     hasher: Hasher<[u8; 3]>,
 }
diff --git a/src/test/rustdoc/const-value-display.rs b/src/test/rustdoc/const-value-display.rs
index 5b2f3c48d57f..8d95f0de9d09 100644
--- a/src/test/rustdoc/const-value-display.rs
+++ b/src/test/rustdoc/const-value-display.rs
@@ -1,9 +1,9 @@
 #![crate_name = "foo"]
 
 // @has 'foo/constant.HOUR_IN_SECONDS.html'
-// @has - '//*[@class="docblock item-decl"]//code' 'pub const HOUR_IN_SECONDS: u64 = _; // 3_600u64'
+// @has - '//*[@class="item-decl"]//code' 'pub const HOUR_IN_SECONDS: u64 = _; // 3_600u64'
 pub const HOUR_IN_SECONDS: u64 = 60 * 60;
 
 // @has 'foo/constant.NEGATIVE.html'
-// @has - '//*[@class="docblock item-decl"]//code' 'pub const NEGATIVE: i64 = _; // -3_600i64'
+// @has - '//*[@class="item-decl"]//code' 'pub const NEGATIVE: i64 = _; // -3_600i64'
 pub const NEGATIVE: i64 = -60 * 60;
diff --git a/src/test/rustdoc/decl-trailing-whitespace.rs b/src/test/rustdoc/decl-trailing-whitespace.rs
index 46a2307abef0..e47edc132185 100644
--- a/src/test/rustdoc/decl-trailing-whitespace.rs
+++ b/src/test/rustdoc/decl-trailing-whitespace.rs
@@ -7,7 +7,7 @@ pub struct Error;
 // @has 'foo/trait.Write.html'
 
 pub trait Write {
-    // @snapshot 'declaration' - '//*[@class="docblock item-decl"]//code'
+    // @snapshot 'declaration' - '//*[@class="item-decl"]//code'
     fn poll_write(
         self: Option<String>,
         cx: &mut Option<String>,
diff --git a/src/test/rustdoc/doc_auto_cfg_nested_impl.rs b/src/test/rustdoc/doc_auto_cfg_nested_impl.rs
new file mode 100644
index 000000000000..4d73e0d829ad
--- /dev/null
+++ b/src/test/rustdoc/doc_auto_cfg_nested_impl.rs
@@ -0,0 +1,24 @@
+// Regression test for <https://github.com/rust-lang/rust/issues/101129>.
+
+#![feature(doc_auto_cfg)]
+#![crate_type = "lib"]
+#![crate_name = "foo"]
+
+pub struct S;
+pub trait MyTrait1 {}
+pub trait MyTrait2 {}
+
+// @has foo/struct.S.html
+// @has - '//*[@id="impl-MyTrait1-for-S"]//*[@class="stab portability"]' \
+//        'Available on non-crate feature coolstuff only.'
+#[cfg(not(feature = "coolstuff"))]
+impl MyTrait1 for S {}
+
+#[cfg(not(feature = "coolstuff"))]
+mod submod {
+    use crate::{S, MyTrait2};
+    // This impl should also have the `not(feature = "coolstuff")`.
+    // @has - '//*[@id="impl-MyTrait2-for-S"]//*[@class="stab portability"]' \
+    //        'Available on non-crate feature coolstuff only.'
+    impl MyTrait2 for S {}
+}
diff --git a/src/test/rustdoc/duplicate_impls/issue-33054.rs b/src/test/rustdoc/duplicate_impls/issue-33054.rs
index 84c9e4ac0cd8..c1f95ac91c39 100644
--- a/src/test/rustdoc/duplicate_impls/issue-33054.rs
+++ b/src/test/rustdoc/duplicate_impls/issue-33054.rs
@@ -1,12 +1,12 @@
 // ignore-tidy-linelength
 
 // @has issue_33054/impls/struct.Foo.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Foo'
-// @has - '//h3[@class="code-header in-band"]' 'impl Bar for Foo'
+// @has - '//h3[@class="code-header"]' 'impl Foo'
+// @has - '//h3[@class="code-header"]' 'impl Bar for Foo'
 // @count - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]' 1
 // @count - '//*[@id="main-content"]/div[@id="implementations-list"]/details/summary/*[@class="impl has-srclink"]' 1
 // @has issue_33054/impls/bar/trait.Bar.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Bar for Foo'
+// @has - '//h3[@class="code-header"]' 'impl Bar for Foo'
 // @count - '//*[@class="struct"]' 1
 pub mod impls;
 
diff --git a/src/test/rustdoc/elided-lifetime.rs b/src/test/rustdoc/elided-lifetime.rs
index 9b4ceb4f9cd8..006132ef8aa4 100644
--- a/src/test/rustdoc/elided-lifetime.rs
+++ b/src/test/rustdoc/elided-lifetime.rs
@@ -3,7 +3,7 @@
 // rust-lang/rust#75225
 //
 // Since Rust 2018 we encourage writing out <'_> explicitly to make it clear
-// that borrowing is occuring. Make sure rustdoc is following the same idiom.
+// that borrowing is occurring. Make sure rustdoc is following the same idiom.
 
 #![crate_name = "foo"]
 
diff --git a/src/test/rustdoc/empty-impl-block.rs b/src/test/rustdoc/empty-impl-block.rs
index 6a2a254f63a7..95d4db06b317 100644
--- a/src/test/rustdoc/empty-impl-block.rs
+++ b/src/test/rustdoc/empty-impl-block.rs
@@ -16,5 +16,5 @@ pub struct Another;
 pub trait Bar {}
 
 // @has 'foo/struct.Another.html'
-// @has - '//h3[@class="code-header in-band"]' 'impl Bar for Another'
+// @has - '//h3[@class="code-header"]' 'impl Bar for Another'
 impl Bar for Another {}
diff --git a/src/test/rustdoc/extern-impl.rs b/src/test/rustdoc/extern-impl.rs
index f357d65df94b..fd1bc2140083 100644
--- a/src/test/rustdoc/extern-impl.rs
+++ b/src/test/rustdoc/extern-impl.rs
@@ -19,9 +19,9 @@ impl Foo {
 // @has foo/trait.Bar.html
 pub trait Bar {}
 
-// @has - '//h3[@class="code-header in-band"]' 'impl Bar for fn()'
+// @has - '//h3[@class="code-header"]' 'impl Bar for fn()'
 impl Bar for fn() {}
-// @has - '//h3[@class="code-header in-band"]' 'impl Bar for extern "C" fn()'
+// @has - '//h3[@class="code-header"]' 'impl Bar for extern "C" fn()'
 impl Bar for extern fn() {}
-// @has - '//h3[@class="code-header in-band"]' 'impl Bar for extern "system" fn()'
+// @has - '//h3[@class="code-header"]' 'impl Bar for extern "system" fn()'
 impl Bar for extern "system" fn() {}
diff --git a/src/test/rustdoc/fn-bound.rs b/src/test/rustdoc/fn-bound.rs
index 4c4ffddc8a64..9e060ff2026f 100644
--- a/src/test/rustdoc/fn-bound.rs
+++ b/src/test/rustdoc/fn-bound.rs
@@ -11,7 +11,7 @@ pub struct ConditionalIterator<F> {
 }
 
 
-// @has 'fn_bound/struct.ConditionalIterator.html' '//h3[@class="code-header in-band"]' 'impl<F: Fn(&i32)> Iterator for ConditionalIterator<F>'
+// @has 'fn_bound/struct.ConditionalIterator.html' '//h3[@class="code-header"]' 'impl<F: Fn(&i32)> Iterator for ConditionalIterator<F>'
 impl<F: Fn(&i32)> Iterator for ConditionalIterator<F> {
     type Item = ();
 
diff --git a/src/test/rustdoc/generic-associated-types/gats.rs b/src/test/rustdoc/generic-associated-types/gats.rs
index ae981b9499a6..bcead3115fef 100644
--- a/src/test/rustdoc/generic-associated-types/gats.rs
+++ b/src/test/rustdoc/generic-associated-types/gats.rs
@@ -1,9 +1,8 @@
 #![crate_name = "foo"]
-#![feature(generic_associated_types)]
 
 // @has foo/trait.LendingIterator.html
 pub trait LendingIterator {
-    // @has - '//*[@id="associatedtype.Item"]//h4[@class="code-header"]' "type Item<'a> where Self: 'a"
+    // @has - '//*[@id="associatedtype.Item"]//h4[@class="code-header"]' "type Item<'a>where Self: 'a"
     type Item<'a> where Self: 'a;
 
     // @has - '//*[@id="tymethod.next"]//h4[@class="code-header"]' \
@@ -24,7 +23,7 @@ impl LendingIterator for () {
 pub struct Infinite<T>(T);
 
 // @has foo/trait.LendingIterator.html
-// @has - '//*[@id="associatedtype.Item-2"]//h4[@class="code-header"]' "type Item<'a> where Self: 'a = &'a T"
+// @has - '//*[@id="associatedtype.Item-2"]//h4[@class="code-header"]' "type Item<'a>where Self: 'a = &'a T"
 impl<T> LendingIterator for Infinite<T> {
     type Item<'a> where Self: 'a = &'a T;
 
diff --git a/src/test/rustdoc/generic-associated-types/issue-94683.rs b/src/test/rustdoc/generic-associated-types/issue-94683.rs
index 91499100ec68..985c7e983aa0 100644
--- a/src/test/rustdoc/generic-associated-types/issue-94683.rs
+++ b/src/test/rustdoc/generic-associated-types/issue-94683.rs
@@ -1,5 +1,4 @@
 #![crate_name = "foo"]
-#![feature(generic_associated_types)]
 
 pub trait Trait {
     type Gat<'a>;
diff --git a/src/test/rustdoc/generic-impl.rs b/src/test/rustdoc/generic-impl.rs
index c6beed70abeb..6f68b1574992 100644
--- a/src/test/rustdoc/generic-impl.rs
+++ b/src/test/rustdoc/generic-impl.rs
@@ -5,7 +5,7 @@ use std::fmt;
 // @!has foo/struct.Bar.html '//*[@id="impl-ToString-for-Bar"]' ''
 pub struct Bar;
 
-// @has foo/struct.Foo.html '//*[@id="impl-ToString-for-Foo"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
+// @has foo/struct.Foo.html '//*[@id="impl-ToString-for-Foo"]//h3[@class="code-header"]' 'impl<T> ToString for T'
 pub struct Foo;
 // @has foo/struct.Foo.html '//*[@class="sidebar-elems"]//section//a[@href="#impl-ToString-for-Foo"]' 'ToString'
 
diff --git a/src/test/rustdoc/glob-shadowing-const.rs b/src/test/rustdoc/glob-shadowing-const.rs
new file mode 100644
index 000000000000..5b786cf53f29
--- /dev/null
+++ b/src/test/rustdoc/glob-shadowing-const.rs
@@ -0,0 +1,20 @@
+// https://github.com/rust-lang/rust/pull/83872#issuecomment-820101008
+#![crate_name="foo"]
+
+mod sub4 {
+    /// 0
+    pub const X: usize = 0;
+    pub mod inner {
+        pub use super::*;
+        /// 1
+        pub const X: usize = 1;
+    }
+}
+
+#[doc(inline)]
+pub use sub4::inner::*;
+
+// @has 'foo/index.html'
+// @has - '//div[@class="item-right docblock-short"]' '1'
+// @!has - '//div[@class="item-right docblock-short"]' '0'
+fn main() { assert_eq!(X, 1); }
diff --git a/src/test/rustdoc/glob-shadowing.rs b/src/test/rustdoc/glob-shadowing.rs
new file mode 100644
index 000000000000..66a31c42bcfc
--- /dev/null
+++ b/src/test/rustdoc/glob-shadowing.rs
@@ -0,0 +1,86 @@
+// @has 'glob_shadowing/index.html'
+// @count - '//div[@class="item-left module-item"]' 6
+// @!has - '//div[@class="item-right docblock-short"]' 'sub1::describe'
+// @has - '//div[@class="item-right docblock-short"]' 'sub2::describe'
+
+// @!has - '//div[@class="item-right docblock-short"]' 'sub1::describe2'
+
+// @!has - '//div[@class="item-right docblock-short"]' 'sub1::prelude'
+// @has - '//div[@class="item-right docblock-short"]' 'mod::prelude'
+
+// @has - '//div[@class="item-right docblock-short"]' 'sub1::Foo (struct)'
+// @has - '//div[@class="item-right docblock-short"]' 'mod::Foo (function)'
+
+// @has - '//div[@class="item-right docblock-short"]' 'sub4::inner::X'
+
+// @has 'glob_shadowing/fn.describe.html'
+// @has - '//div[@class="docblock"]' 'sub2::describe'
+
+mod sub1 {
+    // this should be shadowed by sub2::describe
+    /// sub1::describe
+    pub fn describe() -> &'static str {
+        "sub1::describe"
+    }
+
+    // this should be shadowed by mod::prelude
+    /// sub1::prelude
+    pub mod prelude {
+    }
+
+    // this should *not* be shadowed, because sub1::Foo and mod::Foo are in different namespaces
+    /// sub1::Foo (struct)
+    pub struct Foo;
+
+    // this should be shadowed,
+    // because both sub1::describe2 and sub3::describe2 are from glob reexport
+    /// sub1::describe2
+    pub fn describe2() -> &'static str {
+        "sub1::describe2"
+    }
+}
+
+mod sub2 {
+    /// sub2::describe
+    pub fn describe() -> &'static str {
+        "sub2::describe"
+    }
+}
+
+mod sub3 {
+    // this should be shadowed
+    // because both sub1::describe2 and sub3::describe2 are from glob reexport
+    /// sub3::describe2
+    pub fn describe2() -> &'static str {
+        "sub3::describe2"
+    }
+}
+
+mod sub4 {
+    // this should be shadowed by sub4::inner::X
+    /// sub4::X
+    pub const X: usize = 0;
+    pub mod inner {
+        pub use super::*;
+        /// sub4::inner::X
+        pub const X: usize = 1;
+    }
+}
+
+/// mod::Foo (function)
+pub fn Foo() {}
+
+#[doc(inline)]
+pub use sub2::describe;
+
+#[doc(inline)]
+pub use sub1::*;
+
+#[doc(inline)]
+pub use sub3::*;
+
+#[doc(inline)]
+pub use sub4::inner::*;
+
+/// mod::prelude
+pub mod prelude {}
diff --git a/src/test/rustdoc/higher-ranked-trait-bounds.rs b/src/test/rustdoc/higher-ranked-trait-bounds.rs
index b75b8de52f9c..3493ae6d2bbb 100644
--- a/src/test/rustdoc/higher-ranked-trait-bounds.rs
+++ b/src/test/rustdoc/higher-ranked-trait-bounds.rs
@@ -4,7 +4,7 @@
 pub trait Trait<'x> {}
 
 // @has foo/fn.test1.html
-// @has - '//pre' "pub fn test1<T>() where for<'a> &'a T: Iterator,"
+// @has - '//pre' "pub fn test1<T>()where for<'a> &'a T: Iterator,"
 pub fn test1<T>()
 where
     for<'a> &'a T: Iterator,
@@ -12,7 +12,7 @@ where
 }
 
 // @has foo/fn.test2.html
-// @has - '//pre' "pub fn test2<T>() where for<'a, 'b> &'a T: Trait<'b>,"
+// @has - '//pre' "pub fn test2<T>()where for<'a, 'b> &'a T: Trait<'b>,"
 pub fn test2<T>()
 where
     for<'a, 'b> &'a T: Trait<'b>,
@@ -20,7 +20,7 @@ where
 }
 
 // @has foo/fn.test3.html
-// @has - '//pre' "pub fn test3<F>() where F: for<'a, 'b> Fn(&'a u8, &'b u8),"
+// @has - '//pre' "pub fn test3<F>()where F: for<'a, 'b> Fn(&'a u8, &'b u8),"
 pub fn test3<F>()
 where
     F: for<'a, 'b> Fn(&'a u8, &'b u8),
@@ -38,7 +38,7 @@ pub struct Foo<'a> {
 // @has - '//span[@id="structfield.some_trait"]' "some_trait: &'a dyn for<'b> Trait<'b>"
 
 impl<'a> Foo<'a> {
-    // @has - '//h4[@class="code-header"]' "pub fn bar<T>() where T: Trait<'a>,"
+    // @has - '//h4[@class="code-header"]' "pub fn bar<T>()where T: Trait<'a>,"
     pub fn bar<T>()
     where
         T: Trait<'a>,
@@ -49,7 +49,7 @@ impl<'a> Foo<'a> {
 // @has foo/trait.B.html
 pub trait B<'x> {}
 
-// @has - '//h3[@class="code-header in-band"]' "impl<'a> B<'a> for dyn for<'b> Trait<'b>"
+// @has - '//h3[@class="code-header"]' "impl<'a> B<'a> for dyn for<'b> Trait<'b>"
 impl<'a> B<'a> for dyn for<'b> Trait<'b> {}
 
 // @has foo/struct.Bar.html
diff --git a/src/test/rustdoc/impl-disambiguation.rs b/src/test/rustdoc/impl-disambiguation.rs
index d1d39ccff328..bb978dc0f3ec 100644
--- a/src/test/rustdoc/impl-disambiguation.rs
+++ b/src/test/rustdoc/impl-disambiguation.rs
@@ -4,13 +4,13 @@ pub trait Foo {}
 
 pub struct Bar<T> { field: T }
 
-// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header in-band"]' \
+// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header"]' \
 //     "impl Foo for Bar<u8>"
 impl Foo for Bar<u8> {}
-// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header in-band"]' \
+// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header"]' \
 //     "impl Foo for Bar<u16>"
 impl Foo for Bar<u16> {}
-// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header in-band"]' \
+// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header"]' \
 //     "impl<'a> Foo for &'a Bar<u8>"
 impl<'a> Foo for &'a Bar<u8> {}
 
@@ -22,9 +22,9 @@ pub mod mod2 {
     pub enum Baz {}
 }
 
-// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header in-band"]' \
+// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header"]' \
 //     "impl Foo for foo::mod1::Baz"
 impl Foo for mod1::Baz {}
-// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header in-band"]' \
+// @has foo/trait.Foo.html '//*[@class="item-list"]//h3[@class="code-header"]' \
 //     "impl<'a> Foo for &'a foo::mod2::Baz"
 impl<'a> Foo for &'a mod2::Baz {}
diff --git a/src/test/rustdoc/impl-parts.rs b/src/test/rustdoc/impl-parts.rs
index 249158c1a1f8..0a8c2c8d2a9e 100644
--- a/src/test/rustdoc/impl-parts.rs
+++ b/src/test/rustdoc/impl-parts.rs
@@ -5,8 +5,8 @@ pub auto trait AnAutoTrait {}
 
 pub struct Foo<T> { field: T }
 
-// @has impl_parts/struct.Foo.html '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-//     "impl<T: Clone> !AnAutoTrait for Foo<T> where T: Sync,"
-// @has impl_parts/trait.AnAutoTrait.html '//*[@class="item-list"]//h3[@class="code-header in-band"]' \
-//     "impl<T: Clone> !AnAutoTrait for Foo<T> where T: Sync,"
+// @has impl_parts/struct.Foo.html '//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+//     "impl<T: Clone> !AnAutoTrait for Foo<T>where T: Sync,"
+// @has impl_parts/trait.AnAutoTrait.html '//*[@class="item-list"]//h3[@class="code-header"]' \
+//     "impl<T: Clone> !AnAutoTrait for Foo<T>where T: Sync,"
 impl<T: Clone> !AnAutoTrait for Foo<T> where T: Sync {}
diff --git a/src/test/rustdoc/index-page.rs b/src/test/rustdoc/index-page.rs
index be668a1276a0..5677019fbb88 100644
--- a/src/test/rustdoc/index-page.rs
+++ b/src/test/rustdoc/index-page.rs
@@ -6,6 +6,6 @@
 
 // @has foo/../index.html
 // @has - '//span[@class="in-band"]' 'List of all crates'
-// @has - '//ul[@class="crate mod"]//a[@href="foo/index.html"]' 'foo'
-// @has - '//ul[@class="crate mod"]//a[@href="all_item_types/index.html"]' 'all_item_types'
+// @has - '//ul[@class="all-items"]//a[@href="foo/index.html"]' 'foo'
+// @has - '//ul[@class="all-items"]//a[@href="all_item_types/index.html"]' 'all_item_types'
 pub struct Foo;
diff --git a/src/test/rustdoc/infinite-redirection.rs b/src/test/rustdoc/infinite-redirection.rs
index 96a43323ce29..f037a8e1a83d 100644
--- a/src/test/rustdoc/infinite-redirection.rs
+++ b/src/test/rustdoc/infinite-redirection.rs
@@ -7,7 +7,7 @@
 // @has 'foo/builders/struct.ActionRowBuilder.html'
 // @has - '//*[@id="synthetic-implementations"]' 'Auto Trait Implementations'
 
-// And that the link in the module is targetting it.
+// And that the link in the module is targeting it.
 // @has 'foo/builders/index.html'
 // @has - '//a[@href="struct.ActionRowBuilder.html"]' 'ActionRowBuilder'
 
diff --git a/src/test/rustdoc/inline_cross/issue-31948-1.rs b/src/test/rustdoc/inline_cross/issue-31948-1.rs
index be8585dd16e1..6e89167b3a45 100644
--- a/src/test/rustdoc/inline_cross/issue-31948-1.rs
+++ b/src/test/rustdoc/inline_cross/issue-31948-1.rs
@@ -5,22 +5,22 @@
 extern crate rustdoc_nonreachable_impls;
 
 // @has issue_31948_1/struct.Wobble.html
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Bark for'
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Woof for'
-// @!has - '//*[@class="impl"]//h3[@class="code-header in-band"]' 'Bar for'
-// @!has - '//*[@class="impl"]//h3[@class="code-header in-band"]' 'Qux for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Bark for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Woof for'
+// @!has - '//*[@class="impl"]//h3[@class="code-header"]' 'Bar for'
+// @!has - '//*[@class="impl"]//h3[@class="code-header"]' 'Qux for'
 pub use rustdoc_nonreachable_impls::hidden::Wobble;
 
 // @has issue_31948_1/trait.Bark.html
-// @has - '//h3[@class="code-header in-band"]' 'for Foo'
-// @has - '//h3[@class="code-header in-band"]' 'for Wobble'
-// @!has - '//h3[@class="code-header in-band"]' 'for Wibble'
+// @has - '//h3[@class="code-header"]' 'for Foo'
+// @has - '//h3[@class="code-header"]' 'for Wobble'
+// @!has - '//h3[@class="code-header"]' 'for Wibble'
 pub use rustdoc_nonreachable_impls::Bark;
 
 // @has issue_31948_1/trait.Woof.html
-// @has - '//h3[@class="code-header in-band"]' 'for Foo'
-// @has - '//h3[@class="code-header in-band"]' 'for Wobble'
-// @!has - '//h3[@class="code-header in-band"]' 'for Wibble'
+// @has - '//h3[@class="code-header"]' 'for Foo'
+// @has - '//h3[@class="code-header"]' 'for Wobble'
+// @!has - '//h3[@class="code-header"]' 'for Wibble'
 pub use rustdoc_nonreachable_impls::Woof;
 
 // @!has issue_31948_1/trait.Bar.html
diff --git a/src/test/rustdoc/inline_cross/issue-31948-2.rs b/src/test/rustdoc/inline_cross/issue-31948-2.rs
index 7aa994f19d6f..141e07656a09 100644
--- a/src/test/rustdoc/inline_cross/issue-31948-2.rs
+++ b/src/test/rustdoc/inline_cross/issue-31948-2.rs
@@ -5,15 +5,15 @@
 extern crate rustdoc_nonreachable_impls;
 
 // @has issue_31948_2/struct.Wobble.html
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Qux for'
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Bark for'
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Woof for'
-// @!has - '//*[@class="impl"]//h3[@class="code-header in-band"]' 'Bar for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Qux for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Bark for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Woof for'
+// @!has - '//*[@class="impl"]//h3[@class="code-header"]' 'Bar for'
 pub use rustdoc_nonreachable_impls::hidden::Wobble;
 
 // @has issue_31948_2/trait.Qux.html
-// @has - '//h3[@class="code-header in-band"]' 'for Foo'
-// @has - '//h3[@class="code-header in-band"]' 'for Wobble'
+// @has - '//h3[@class="code-header"]' 'for Foo'
+// @has - '//h3[@class="code-header"]' 'for Wobble'
 pub use rustdoc_nonreachable_impls::hidden::Qux;
 
 // @!has issue_31948_2/trait.Bar.html
diff --git a/src/test/rustdoc/inline_cross/issue-31948.rs b/src/test/rustdoc/inline_cross/issue-31948.rs
index 7bf4110d32ac..96fc6ca47e7f 100644
--- a/src/test/rustdoc/inline_cross/issue-31948.rs
+++ b/src/test/rustdoc/inline_cross/issue-31948.rs
@@ -5,22 +5,22 @@
 extern crate rustdoc_nonreachable_impls;
 
 // @has issue_31948/struct.Foo.html
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Bark for'
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Woof for'
-// @!has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'Bar for'
-// @!has - '//*[@class="impl"]//h3[@class="code-header in-band"]' 'Qux for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Bark for'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Woof for'
+// @!has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'Bar for'
+// @!has - '//*[@class="impl"]//h3[@class="code-header"]' 'Qux for'
 pub use rustdoc_nonreachable_impls::Foo;
 
 // @has issue_31948/trait.Bark.html
-// @has - '//h3[@class="code-header in-band"]' 'for Foo'
-// @!has - '//h3[@class="code-header in-band"]' 'for Wibble'
-// @!has - '//h3[@class="code-header in-band"]' 'for Wobble'
+// @has - '//h3[@class="code-header"]' 'for Foo'
+// @!has - '//h3[@class="code-header"]' 'for Wibble'
+// @!has - '//h3[@class="code-header"]' 'for Wobble'
 pub use rustdoc_nonreachable_impls::Bark;
 
 // @has issue_31948/trait.Woof.html
-// @has - '//h3[@class="code-header in-band"]' 'for Foo'
-// @!has - '//h3[@class="code-header in-band"]' 'for Wibble'
-// @!has - '//h3[@class="code-header in-band"]' 'for Wobble'
+// @has - '//h3[@class="code-header"]' 'for Foo'
+// @!has - '//h3[@class="code-header"]' 'for Wibble'
+// @!has - '//h3[@class="code-header"]' 'for Wobble'
 pub use rustdoc_nonreachable_impls::Woof;
 
 // @!has issue_31948/trait.Bar.html
diff --git a/src/test/rustdoc/inline_cross/issue-32881.rs b/src/test/rustdoc/inline_cross/issue-32881.rs
index 8052339a83b6..183fd15abbe1 100644
--- a/src/test/rustdoc/inline_cross/issue-32881.rs
+++ b/src/test/rustdoc/inline_cross/issue-32881.rs
@@ -5,7 +5,7 @@
 extern crate rustdoc_trait_object_impl;
 
 // @has issue_32881/trait.Bar.html
-// @has - '//h3[@class="code-header in-band"]' "impl<'a> dyn Bar"
-// @has - '//h3[@class="code-header in-band"]' "impl<'a> Debug for dyn Bar"
+// @has - '//h3[@class="code-header"]' "impl<'a> dyn Bar"
+// @has - '//h3[@class="code-header"]' "impl<'a> Debug for dyn Bar"
 
 pub use rustdoc_trait_object_impl::Bar;
diff --git a/src/test/rustdoc/inline_cross/issue-33113.rs b/src/test/rustdoc/inline_cross/issue-33113.rs
index c60859bbcea9..d954707facfe 100644
--- a/src/test/rustdoc/inline_cross/issue-33113.rs
+++ b/src/test/rustdoc/inline_cross/issue-33113.rs
@@ -5,6 +5,6 @@
 extern crate bar;
 
 // @has issue_33113/trait.Bar.html
-// @has - '//h3[@class="code-header in-band"]' "for &'a char"
-// @has - '//h3[@class="code-header in-band"]' "for Foo"
+// @has - '//h3[@class="code-header"]' "for &'a char"
+// @has - '//h3[@class="code-header"]' "for Foo"
 pub use bar::Bar;
diff --git a/src/test/rustdoc/inline_cross/trait-vis.rs b/src/test/rustdoc/inline_cross/trait-vis.rs
index 363c52a336e4..b646babacc5c 100644
--- a/src/test/rustdoc/inline_cross/trait-vis.rs
+++ b/src/test/rustdoc/inline_cross/trait-vis.rs
@@ -3,5 +3,5 @@
 extern crate inner;
 
 // @has trait_vis/struct.SomeStruct.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Clone for SomeStruct'
+// @has - '//h3[@class="code-header"]' 'impl Clone for SomeStruct'
 pub use inner::SomeStruct;
diff --git a/src/test/rustdoc/inline_local/trait-vis.rs b/src/test/rustdoc/inline_local/trait-vis.rs
index e7b08088f403..19b69da15138 100644
--- a/src/test/rustdoc/inline_local/trait-vis.rs
+++ b/src/test/rustdoc/inline_local/trait-vis.rs
@@ -13,6 +13,6 @@ mod asdf {
 }
 
 // @has trait_vis/struct.SomeStruct.html
-// @has - '//h3[@class="code-header in-band"]' 'impl ThisTrait for SomeStruct'
-// @!has - '//h3[@class="code-header in-band"]' 'impl PrivateTrait for SomeStruct'
+// @has - '//h3[@class="code-header"]' 'impl ThisTrait for SomeStruct'
+// @!has - '//h3[@class="code-header"]' 'impl PrivateTrait for SomeStruct'
 pub use asdf::SomeStruct;
diff --git a/src/test/rustdoc/issue-101743-bold-tag.rs b/src/test/rustdoc/issue-101743-bold-tag.rs
new file mode 100644
index 000000000000..631181fec66c
--- /dev/null
+++ b/src/test/rustdoc/issue-101743-bold-tag.rs
@@ -0,0 +1,19 @@
+// Regression test for https://github.com/rust-lang/rust/issues/101743
+
+#![crate_name="foo"]
+
+pub type Word = usize;
+pub struct Repr<const B: usize>([i32; B]);
+pub struct IBig(usize);
+
+pub const fn base_as_ibig<const B: Word>() -> IBig {
+    IBig(B)
+}
+
+impl<const B: Word> Repr<B> {
+    // If we change back to rendering the value of consts, check this doesn't add
+    // a <b> tag, but escapes correctly
+
+    // @has foo/struct.Repr.html '//section[@id="associatedconstant.BASE"]/h4' '= _'
+    pub const BASE: IBig = base_as_ibig::<B>();
+}
diff --git a/src/test/rustdoc/issue-20727-4.rs b/src/test/rustdoc/issue-20727-4.rs
index 84fc6f94a265..643f93875909 100644
--- a/src/test/rustdoc/issue-20727-4.rs
+++ b/src/test/rustdoc/issue-20727-4.rs
@@ -25,7 +25,7 @@ pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
 
 pub mod reexport {
     // @has issue_20727_4/reexport/trait.Index.html
-    // @has - '//*[@class="rust trait"]' 'trait Index<Idx> where Idx: ?Sized, {'
+    // @has - '//*[@class="rust trait"]' 'trait Index<Idx>where Idx: ?Sized,{'
     // @has - '//*[@class="rust trait"]' 'type Output: ?Sized'
     // @has - '//*[@class="rust trait"]' \
     //        'fn index(&self, index: Idx) -> &Self::Output'
@@ -33,7 +33,7 @@ pub mod reexport {
 
     // @has issue_20727_4/reexport/trait.IndexMut.html
     // @has - '//*[@class="rust trait"]' \
-    //        'trait IndexMut<Idx>: Index<Idx> where Idx: ?Sized, {'
+    //        'trait IndexMut<Idx>: Index<Idx>where Idx: ?Sized,{'
     // @has - '//*[@class="rust trait"]' \
     //        'fn index_mut(&mut self, index: Idx) -> &mut Self::Output;'
     pub use issue_20727::IndexMut;
diff --git a/src/test/rustdoc/issue-21801.rs b/src/test/rustdoc/issue-21801.rs
index 2a586b6ff6cd..29d2ec64c206 100644
--- a/src/test/rustdoc/issue-21801.rs
+++ b/src/test/rustdoc/issue-21801.rs
@@ -5,5 +5,5 @@ extern crate issue_21801;
 
 // @has issue_21801/struct.Foo.html
 // @has - '//*[@id="method.new"]' \
-//        'fn new<F>(f: F) -> Foo where F: FnMut() -> i32'
+//        'fn new<F>(f: F) -> Foowhere F: FnMut() -> i32'
 pub use issue_21801::Foo;
diff --git a/src/test/rustdoc/issue-29503.rs b/src/test/rustdoc/issue-29503.rs
index 635c3175f813..01ae4438500d 100644
--- a/src/test/rustdoc/issue-29503.rs
+++ b/src/test/rustdoc/issue-29503.rs
@@ -5,7 +5,7 @@ pub trait MyTrait {
     fn my_string(&self) -> String;
 }
 
-// @has - "//div[@id='implementors-list']//*[@id='impl-MyTrait-for-T']//h3[@class='code-header in-band']" "impl<T> MyTrait for T where T: Debug"
+// @has - "//div[@id='implementors-list']//*[@id='impl-MyTrait-for-T']//h3[@class='code-header']" "impl<T> MyTrait for Twhere T: Debug"
 impl<T> MyTrait for T
 where
     T: fmt::Debug,
diff --git a/src/test/rustdoc/issue-33592.rs b/src/test/rustdoc/issue-33592.rs
index 815439db9bfd..7a128f0b897e 100644
--- a/src/test/rustdoc/issue-33592.rs
+++ b/src/test/rustdoc/issue-33592.rs
@@ -6,8 +6,8 @@ pub struct Bar;
 
 pub struct Baz;
 
-// @has foo/trait.Foo.html '//h3[@class="code-header in-band"]' 'impl Foo<i32> for Bar'
+// @has foo/trait.Foo.html '//h3[@class="code-header"]' 'impl Foo<i32> for Bar'
 impl Foo<i32> for Bar {}
 
-// @has foo/trait.Foo.html '//h3[@class="code-header in-band"]' 'impl<T> Foo<T> for Baz'
+// @has foo/trait.Foo.html '//h3[@class="code-header"]' 'impl<T> Foo<T> for Baz'
 impl<T> Foo<T> for Baz {}
diff --git a/src/test/rustdoc/issue-34928.rs b/src/test/rustdoc/issue-34928.rs
index 4184086f622a..91b67757453d 100644
--- a/src/test/rustdoc/issue-34928.rs
+++ b/src/test/rustdoc/issue-34928.rs
@@ -2,5 +2,5 @@
 
 pub trait Bar {}
 
-// @has foo/struct.Foo.html '//pre' 'pub struct Foo<T>(pub T) where T: Bar;'
+// @has foo/struct.Foo.html '//pre' 'pub struct Foo<T>(pub T)where T: Bar;'
 pub struct Foo<T>(pub T) where T: Bar;
diff --git a/src/test/rustdoc/issue-46727.rs b/src/test/rustdoc/issue-46727.rs
index 00e9127a34d2..8cfc4827a7f4 100644
--- a/src/test/rustdoc/issue-46727.rs
+++ b/src/test/rustdoc/issue-46727.rs
@@ -3,5 +3,5 @@
 extern crate issue_46727;
 
 // @has issue_46727/trait.Foo.html
-// @has - '//h3[@class="code-header in-band"]' 'impl<T> Foo for Bar<[T; 3]>'
+// @has - '//h3[@class="code-header"]' 'impl<T> Foo for Bar<[T; 3]>'
 pub use issue_46727::{Foo, Bar};
diff --git a/src/test/rustdoc/issue-50159.rs b/src/test/rustdoc/issue-50159.rs
index d88c29217023..04bc4f304d68 100644
--- a/src/test/rustdoc/issue-50159.rs
+++ b/src/test/rustdoc/issue-50159.rs
@@ -11,8 +11,8 @@ impl<B, C> Signal2 for B where B: Signal<Item = C> {
 }
 
 // @has issue_50159/struct.Switch.html
-// @has - '//h3[@class="code-header in-band"]' 'impl<B> Send for Switch<B> where <B as Signal>::Item: Send'
-// @has - '//h3[@class="code-header in-band"]' 'impl<B> Sync for Switch<B> where <B as Signal>::Item: Sync'
+// @has - '//h3[@class="code-header"]' 'impl<B> Send for Switch<B>where <B as Signal>::Item: Send'
+// @has - '//h3[@class="code-header"]' 'impl<B> Sync for Switch<B>where <B as Signal>::Item: Sync'
 // @count - '//*[@id="implementations-list"]//*[@class="impl"]' 0
 // @count - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]' 5
 pub struct Switch<B: Signal> {
diff --git a/src/test/rustdoc/issue-51236.rs b/src/test/rustdoc/issue-51236.rs
index ee11ccc68116..1c7aa9c7eefe 100644
--- a/src/test/rustdoc/issue-51236.rs
+++ b/src/test/rustdoc/issue-51236.rs
@@ -7,8 +7,8 @@ pub mod traits {
 }
 
 // @has issue_51236/struct.Owned.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<T> Send for Owned<T> where <T as Owned<'static>>::Reader: Send"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<T> Send for Owned<T>where <T as Owned<'static>>::Reader: Send"
 pub struct Owned<T> where T: for<'a> ::traits::Owned<'a> {
     marker: PhantomData<<T as ::traits::Owned<'static>>::Reader>,
 }
diff --git a/src/test/rustdoc/issue-54705.rs b/src/test/rustdoc/issue-54705.rs
index bedaf5c4ddc3..7b7290ab4b77 100644
--- a/src/test/rustdoc/issue-54705.rs
+++ b/src/test/rustdoc/issue-54705.rs
@@ -1,13 +1,11 @@
 pub trait ScopeHandle<'scope> {}
 
-
-
 // @has issue_54705/struct.ScopeFutureContents.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'scope, S> Send for ScopeFutureContents<'scope, S> where S: Sync"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'scope, S> Send for ScopeFutureContents<'scope, S>where S: Sync"
 //
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'scope, S> Sync for ScopeFutureContents<'scope, S> where S: Sync"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'scope, S> Sync for ScopeFutureContents<'scope, S>where S: Sync"
 pub struct ScopeFutureContents<'scope, S>
     where S: ScopeHandle<'scope>,
 {
diff --git a/src/test/rustdoc/issue-55321.rs b/src/test/rustdoc/issue-55321.rs
index ee2420d86d23..22a18ef90e13 100644
--- a/src/test/rustdoc/issue-55321.rs
+++ b/src/test/rustdoc/issue-55321.rs
@@ -1,9 +1,9 @@
 #![feature(negative_impls)]
 
 // @has issue_55321/struct.A.html
-// @has - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl !Send for A"
-// @has - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl !Sync for A"
 pub struct A();
 
@@ -11,8 +11,8 @@ impl !Send for A {}
 impl !Sync for A {}
 
 // @has issue_55321/struct.B.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<T> !Send for B<T>"
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<T> !Sync for B<T>"
 pub struct B<T: ?Sized>(A, Box<T>);
diff --git a/src/test/rustdoc/issue-56822.rs b/src/test/rustdoc/issue-56822.rs
index aef6ddd8d23b..b4eef344b5f3 100644
--- a/src/test/rustdoc/issue-56822.rs
+++ b/src/test/rustdoc/issue-56822.rs
@@ -17,7 +17,7 @@ impl<'a, T> MyTrait for Inner<'a, T> {
 }
 
 // @has issue_56822/struct.Parser.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<'a> Send for Parser<'a>"
 pub struct Parser<'a> {
     field: <Wrapper<Inner<'a, u8>> as MyTrait>::Output
diff --git a/src/test/rustdoc/issue-60726.rs b/src/test/rustdoc/issue-60726.rs
index 167f0f039c15..fbb0f82ae395 100644
--- a/src/test/rustdoc/issue-60726.rs
+++ b/src/test/rustdoc/issue-60726.rs
@@ -26,9 +26,9 @@ where
 {}
 
 // @has issue_60726/struct.IntoIter.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<T> !Send for IntoIter<T>"
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<T> !Sync for IntoIter<T>"
 pub struct IntoIter<T>{
     hello:DynTrait<FooInterface<T>>,
diff --git a/src/test/rustdoc/issue-75588.rs b/src/test/rustdoc/issue-75588.rs
index ac97b94fb351..3b11059a755d 100644
--- a/src/test/rustdoc/issue-75588.rs
+++ b/src/test/rustdoc/issue-75588.rs
@@ -10,8 +10,8 @@ extern crate realcore;
 extern crate real_gimli;
 
 // issue #74672
-// @!has foo/trait.Deref.html '//*[@id="impl-Deref-for-EndianSlice"]//h3[@class="code-header in-band"]' 'impl Deref for EndianSlice'
+// @!has foo/trait.Deref.html '//*[@id="impl-Deref-for-EndianSlice"]//h3[@class="code-header"]' 'impl Deref for EndianSlice'
 pub use realcore::Deref;
 
-// @has foo/trait.Join.html '//*[@id="impl-Join-for-Foo"]//h3[@class="code-header in-band"]' 'impl Join for Foo'
+// @has foo/trait.Join.html '//*[@id="impl-Join-for-Foo"]//h3[@class="code-header"]' 'impl Join for Foo'
 pub use realcore::Join;
diff --git a/src/test/rustdoc/issue-80233-normalize-auto-trait.rs b/src/test/rustdoc/issue-80233-normalize-auto-trait.rs
index 515e617b4f4c..62fbc2444dbc 100644
--- a/src/test/rustdoc/issue-80233-normalize-auto-trait.rs
+++ b/src/test/rustdoc/issue-80233-normalize-auto-trait.rs
@@ -31,7 +31,7 @@ impl<T: Trait3> Trait3 for Vec<T> {
 pub struct Struct1 {}
 
 // @has issue_80233_normalize_auto_trait/struct.Question.html
-// @has - '//h3[@class="code-header in-band"]' 'impl<T> Send for Question<T>'
+// @has - '//h3[@class="code-header"]' 'impl<T> Send for Question<T>'
 pub struct Question<T: Trait1> {
     pub ins: <<Vec<T> as Trait3>::Type3 as Trait2>::Type2,
 }
diff --git a/src/test/rustdoc/issue-82465-asref-for-and-of-local.rs b/src/test/rustdoc/issue-82465-asref-for-and-of-local.rs
index 8999e6a889bd..adf4d111a6cb 100644
--- a/src/test/rustdoc/issue-82465-asref-for-and-of-local.rs
+++ b/src/test/rustdoc/issue-82465-asref-for-and-of-local.rs
@@ -1,14 +1,14 @@
 use std::convert::AsRef;
 pub struct Local;
 
-// @has issue_82465_asref_for_and_of_local/struct.Local.html '//h3[@class="code-header in-band"]' 'impl AsRef<str> for Local'
+// @has issue_82465_asref_for_and_of_local/struct.Local.html '//h3[@class="code-header"]' 'impl AsRef<str> for Local'
 impl AsRef<str> for Local {
     fn as_ref(&self) -> &str {
         todo!()
     }
 }
 
-// @has - '//h3[@class="code-header in-band"]' 'impl AsRef<Local> for str'
+// @has - '//h3[@class="code-header"]' 'impl AsRef<Local> for str'
 impl AsRef<Local> for str {
     fn as_ref(&self) -> &Local {
         todo!()
diff --git a/src/test/rustdoc/issue-83375-multiple-mods-w-same-name-doc-inline-last-item.rs b/src/test/rustdoc/issue-83375-multiple-mods-w-same-name-doc-inline-last-item.rs
new file mode 100644
index 000000000000..d3a7a870b580
--- /dev/null
+++ b/src/test/rustdoc/issue-83375-multiple-mods-w-same-name-doc-inline-last-item.rs
@@ -0,0 +1,16 @@
+#![crate_name = "foo"]
+
+pub mod sub {
+    pub struct Item;
+
+    pub mod prelude {
+        pub use super::Item;
+    }
+}
+
+#[doc(inline)]
+pub use sub::*;
+
+// @count foo/index.html '//a[@class="mod"][@title="foo::prelude mod"]' 1
+// @count foo/prelude/index.html '//div[@class="item-row"]' 0
+pub mod prelude {}
diff --git a/src/test/rustdoc/issue-83375-multiple-mods-w-same-name-doc-inline.rs b/src/test/rustdoc/issue-83375-multiple-mods-w-same-name-doc-inline.rs
new file mode 100644
index 000000000000..b83692509936
--- /dev/null
+++ b/src/test/rustdoc/issue-83375-multiple-mods-w-same-name-doc-inline.rs
@@ -0,0 +1,16 @@
+#![crate_name = "foo"]
+
+pub mod sub {
+    pub struct Item;
+
+    pub mod prelude {
+        pub use super::Item;
+    }
+}
+
+// @count foo/index.html '//a[@class="mod"][@title="foo::prelude mod"]' 1
+// @count foo/prelude/index.html '//div[@class="item-row"]' 0
+pub mod prelude {}
+
+#[doc(inline)]
+pub use sub::*;
diff --git a/src/test/rustdoc/issue-98697.rs b/src/test/rustdoc/issue-98697.rs
index 83e08094c095..d50268509b2c 100644
--- a/src/test/rustdoc/issue-98697.rs
+++ b/src/test/rustdoc/issue-98697.rs
@@ -8,10 +8,10 @@
 
 extern crate issue_98697_reexport_with_anonymous_lifetime;
 
-// @has issue_98697/fn.repro.html '//pre[@class="rust fn"]/code' 'fn repro<F>() where F: Fn(&str)'
+// @has issue_98697/fn.repro.html '//pre[@class="rust fn"]/code' 'fn repro<F>()where F: Fn(&str)'
 // @!has issue_98697/fn.repro.html '//pre[@class="rust fn"]/code' 'for<'
 pub use issue_98697_reexport_with_anonymous_lifetime::repro;
 
-// @has issue_98697/struct.Extra.html '//div[@id="trait-implementations-list"]//h3[@class="code-header in-band"]' 'impl MyTrait<&Extra> for Extra'
-// @!has issue_98697/struct.Extra.html '//div[@id="trait-implementations-list"]//h3[@class="code-header in-band"]' 'impl<'
+// @has issue_98697/struct.Extra.html '//div[@id="trait-implementations-list"]//h3[@class="code-header"]' 'impl MyTrait<&Extra> for Extra'
+// @!has issue_98697/struct.Extra.html '//div[@id="trait-implementations-list"]//h3[@class="code-header"]' 'impl<'
 pub use issue_98697_reexport_with_anonymous_lifetime::Extra;
diff --git a/src/test/rustdoc/macro-document-private-duplicate.rs b/src/test/rustdoc/macro-document-private-duplicate.rs
index ee3010514417..d3cf7e140650 100644
--- a/src/test/rustdoc/macro-document-private-duplicate.rs
+++ b/src/test/rustdoc/macro-document-private-duplicate.rs
@@ -4,7 +4,7 @@
 // (yes, that's a thing), rustdoc lists both of them on the index page,
 // but only documents the first one on the page for the macro.
 // Fortunately, this can only happen in document private items mode,
-// but it still isn't ideal beahvior.
+// but it still isn't ideal behavior.
 //
 // See https://github.com/rust-lang/rust/pull/88019#discussion_r693920453
 //
diff --git a/src/test/rustdoc/macro-higher-kinded-function.rs b/src/test/rustdoc/macro-higher-kinded-function.rs
index 02a4305644e7..b8c52b7b791d 100644
--- a/src/test/rustdoc/macro-higher-kinded-function.rs
+++ b/src/test/rustdoc/macro-higher-kinded-function.rs
@@ -11,8 +11,8 @@ macro_rules! gen {
 }
 
 // @has 'foo/struct.Providers.html'
-// @has - '//*[@class="docblock item-decl"]//code' "pub a: for<'tcx> fn(_: TyCtxt<'tcx>, _: u8) -> i8,"
-// @has - '//*[@class="docblock item-decl"]//code' "pub b: for<'tcx> fn(_: TyCtxt<'tcx>, _: u16) -> i16,"
+// @has - '//*[@class="item-decl"]//code' "pub a: for<'tcx> fn(_: TyCtxt<'tcx>, _: u8) -> i8,"
+// @has - '//*[@class="item-decl"]//code' "pub b: for<'tcx> fn(_: TyCtxt<'tcx>, _: u16) -> i16,"
 // @has - '//*[@id="structfield.a"]/code' "a: for<'tcx> fn(_: TyCtxt<'tcx>, _: u8) -> i8"
 // @has - '//*[@id="structfield.b"]/code' "b: for<'tcx> fn(_: TyCtxt<'tcx>, _: u16) -> i16"
 gen! {
diff --git a/src/test/rustdoc/negative-impl.rs b/src/test/rustdoc/negative-impl.rs
index 61a239868623..af19c784d6d0 100644
--- a/src/test/rustdoc/negative-impl.rs
+++ b/src/test/rustdoc/negative-impl.rs
@@ -5,10 +5,10 @@ pub struct Alpha;
 // @matches negative_impl/struct.Bravo.html '//pre' "pub struct Bravo<B>"
 pub struct Bravo<B>(B);
 
-// @matches negative_impl/struct.Alpha.html '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @matches negative_impl/struct.Alpha.html '//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl !Send for Alpha"
 impl !Send for Alpha {}
 
-// @matches negative_impl/struct.Bravo.html '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' "\
+// @matches negative_impl/struct.Bravo.html '//*[@class="impl has-srclink"]//h3[@class="code-header"]' "\
 // impl<B> !Send for Bravo<B>"
 impl<B> !Send for Bravo<B> {}
diff --git a/src/test/rustdoc/primitive-reference.rs b/src/test/rustdoc/primitive-reference.rs
index 5c1193406092..431c9aa79c7f 100644
--- a/src/test/rustdoc/primitive-reference.rs
+++ b/src/test/rustdoc/primitive-reference.rs
@@ -14,7 +14,7 @@
 
 // There should be only one implementation listed.
 // @count - '//*[@class="impl has-srclink"]' 1
-// @has - '//*[@id="impl-Foo%3C%26A%3E-for-%26B"]/*[@class="code-header in-band"]' \
+// @has - '//*[@id="impl-Foo%3C%26A%3E-for-%26B"]/*[@class="code-header"]' \
 //        'impl<A, B> Foo<&A> for &B'
 #[doc(primitive = "reference")]
 /// this is a test!
diff --git a/src/test/rustdoc/primitive-slice-auto-trait.rs b/src/test/rustdoc/primitive-slice-auto-trait.rs
index b3f511bc1f15..7f8f74ff457a 100644
--- a/src/test/rustdoc/primitive-slice-auto-trait.rs
+++ b/src/test/rustdoc/primitive-slice-auto-trait.rs
@@ -7,8 +7,8 @@
 // @has - '//span[@class="in-band"]' 'Primitive Type slice'
 // @has - '//section[@id="main-content"]//div[@class="docblock"]//p' 'this is a test!'
 // @has - '//h2[@id="synthetic-implementations"]' 'Auto Trait Implementations'
-// @has - '//div[@id="synthetic-implementations-list"]//h3' 'impl<T> Send for [T] where T: Send'
-// @has - '//div[@id="synthetic-implementations-list"]//h3' 'impl<T> Sync for [T] where T: Sync'
+// @has - '//div[@id="synthetic-implementations-list"]//h3' 'impl<T> Send for [T]where T: Send'
+// @has - '//div[@id="synthetic-implementations-list"]//h3' 'impl<T> Sync for [T]where T: Sync'
 #[doc(primitive = "slice")]
 /// this is a test!
 mod slice_prim {}
diff --git a/src/test/rustdoc/primitive/primitive-generic-impl.rs b/src/test/rustdoc/primitive/primitive-generic-impl.rs
index eebb2cf5a355..7b336b398104 100644
--- a/src/test/rustdoc/primitive/primitive-generic-impl.rs
+++ b/src/test/rustdoc/primitive/primitive-generic-impl.rs
@@ -1,7 +1,7 @@
 #![feature(rustdoc_internals)]
 #![crate_name = "foo"]
 
-// @has foo/primitive.i32.html '//*[@id="impl-ToString-for-i32"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
+// @has foo/primitive.i32.html '//*[@id="impl-ToString-for-i32"]//h3[@class="code-header"]' 'impl<T> ToString for T'
 
 #[doc(primitive = "i32")]
 /// Some useless docs, wouhou!
diff --git a/src/test/rustdoc/recursive-deref.rs b/src/test/rustdoc/recursive-deref.rs
index 2ab9d44be6da..aa38485c4455 100644
--- a/src/test/rustdoc/recursive-deref.rs
+++ b/src/test/rustdoc/recursive-deref.rs
@@ -9,7 +9,7 @@ impl C {
     pub fn c(&self) {}
 }
 
-// @has recursive_deref/struct.A.html '//h3[@class="code-header in-band"]' 'impl Deref for A'
+// @has recursive_deref/struct.A.html '//h3[@class="code-header"]' 'impl Deref for A'
 // @has '-' '//*[@class="impl-items"]//*[@id="method.c"]' 'pub fn c(&self)'
 impl Deref for A {
     type Target = B;
@@ -19,7 +19,7 @@ impl Deref for A {
     }
 }
 
-// @has recursive_deref/struct.B.html '//h3[@class="code-header in-band"]' 'impl Deref for B'
+// @has recursive_deref/struct.B.html '//h3[@class="code-header"]' 'impl Deref for B'
 // @has '-' '//*[@class="impl-items"]//*[@id="method.c"]' 'pub fn c(&self)'
 impl Deref for B {
     type Target = C;
@@ -29,7 +29,7 @@ impl Deref for B {
     }
 }
 
-// @has recursive_deref/struct.C.html '//h3[@class="code-header in-band"]' 'impl Deref for C'
+// @has recursive_deref/struct.C.html '//h3[@class="code-header"]' 'impl Deref for C'
 impl Deref for C {
     type Target = B;
 
@@ -49,7 +49,7 @@ impl G {
     pub fn g() {}
 }
 
-// @has recursive_deref/struct.D.html '//h3[@class="code-header in-band"]' 'impl Deref for D'
+// @has recursive_deref/struct.D.html '//h3[@class="code-header"]' 'impl Deref for D'
 // We also check that `G::g` method isn't rendered because there is no `self` argument.
 // @!has '-' '//*[@id="deref-methods-G"]' ''
 impl Deref for D {
@@ -60,7 +60,7 @@ impl Deref for D {
     }
 }
 
-// @has recursive_deref/struct.E.html '//h3[@class="code-header in-band"]' 'impl Deref for E'
+// @has recursive_deref/struct.E.html '//h3[@class="code-header"]' 'impl Deref for E'
 // We also check that `G::g` method isn't rendered because there is no `self` argument.
 // @!has '-' '//*[@id="deref-methods-G"]' ''
 impl Deref for E {
@@ -71,7 +71,7 @@ impl Deref for E {
     }
 }
 
-// @has recursive_deref/struct.F.html '//h3[@class="code-header in-band"]' 'impl Deref for F'
+// @has recursive_deref/struct.F.html '//h3[@class="code-header"]' 'impl Deref for F'
 // We also check that `G::g` method isn't rendered because there is no `self` argument.
 // @!has '-' '//*[@id="deref-methods-G"]' ''
 impl Deref for F {
@@ -82,7 +82,7 @@ impl Deref for F {
     }
 }
 
-// @has recursive_deref/struct.G.html '//h3[@class="code-header in-band"]' 'impl Deref for G'
+// @has recursive_deref/struct.G.html '//h3[@class="code-header"]' 'impl Deref for G'
 impl Deref for G {
     type Target = E;
 
@@ -100,7 +100,7 @@ impl I {
     pub fn i() {}
 }
 
-// @has recursive_deref/struct.H.html '//h3[@class="code-header in-band"]' 'impl Deref for H'
+// @has recursive_deref/struct.H.html '//h3[@class="code-header"]' 'impl Deref for H'
 // @!has '-' '//*[@id="deref-methods-I"]' ''
 impl Deref for H {
     type Target = I;
@@ -110,7 +110,7 @@ impl Deref for H {
     }
 }
 
-// @has recursive_deref/struct.I.html '//h3[@class="code-header in-band"]' 'impl Deref for I'
+// @has recursive_deref/struct.I.html '//h3[@class="code-header"]' 'impl Deref for I'
 impl Deref for I {
     type Target = H;
 
diff --git a/src/test/rustdoc/reexport-dep-foreign-fn.rs b/src/test/rustdoc/reexport-dep-foreign-fn.rs
index 6e1dc453982d..6694c91d1044 100644
--- a/src/test/rustdoc/reexport-dep-foreign-fn.rs
+++ b/src/test/rustdoc/reexport-dep-foreign-fn.rs
@@ -8,5 +8,5 @@
 extern crate all_item_types;
 
 // @has 'foo/fn.foo_ffn.html'
-// @has - '//*[@class="docblock item-decl"]//code' 'pub unsafe extern "C" fn foo_ffn()'
+// @has - '//*[@class="item-decl"]//code' 'pub unsafe extern "C" fn foo_ffn()'
 pub use all_item_types::foo_ffn;
diff --git a/src/test/rustdoc/reexports-priv.rs b/src/test/rustdoc/reexports-priv.rs
index aea9b9f2b395..11364e7f707e 100644
--- a/src/test/rustdoc/reexports-priv.rs
+++ b/src/test/rustdoc/reexports-priv.rs
@@ -5,7 +5,7 @@
 
 extern crate reexports;
 
-// @has 'foo/macro.addr_of.html' '//*[@class="docblock item-decl"]' 'pub macro addr_of($place:expr) {'
+// @has 'foo/macro.addr_of.html' '//*[@class="item-decl"]' 'pub macro addr_of($place:expr) {'
 pub use reexports::addr_of;
 // @!has 'foo/macro.addr_of_crate.html'
 pub(crate) use reexports::addr_of_crate;
@@ -14,7 +14,7 @@ pub(self) use reexports::addr_of_self;
 // @!has 'foo/macro.addr_of_local.html'
 use reexports::addr_of_local;
 
-// @has 'foo/struct.Foo.html' '//*[@class="docblock item-decl"]' 'pub struct Foo;'
+// @has 'foo/struct.Foo.html' '//*[@class="item-decl"]' 'pub struct Foo;'
 pub use reexports::Foo;
 // @!has 'foo/struct.FooCrate.html'
 pub(crate) use reexports::FooCrate;
@@ -23,7 +23,7 @@ pub(self) use reexports::FooSelf;
 // @!has 'foo/struct.FooLocal.html'
 use reexports::FooLocal;
 
-// @has 'foo/enum.Bar.html' '//*[@class="docblock item-decl"]' 'pub enum Bar {'
+// @has 'foo/enum.Bar.html' '//*[@class="item-decl"]' 'pub enum Bar {'
 pub use reexports::Bar;
 // @!has 'foo/enum.BarCrate.html'
 pub(crate) use reexports::BarCrate;
@@ -50,7 +50,7 @@ pub(self) use reexports::TypeSelf;
 // @!has 'foo/type.TypeLocal.html'
 use reexports::TypeLocal;
 
-// @has 'foo/union.Union.html' '//*[@class="docblock item-decl"]' 'pub union Union {'
+// @has 'foo/union.Union.html' '//*[@class="item-decl"]' 'pub union Union {'
 pub use reexports::Union;
 // @!has 'foo/union.UnionCrate.html'
 pub(crate) use reexports::UnionCrate;
@@ -61,33 +61,33 @@ use reexports::UnionLocal;
 
 pub mod outer {
     pub mod inner {
-        // @has 'foo/outer/inner/macro.addr_of.html' '//*[@class="docblock item-decl"]' 'pub macro addr_of($place:expr) {'
+        // @has 'foo/outer/inner/macro.addr_of.html' '//*[@class="item-decl"]' 'pub macro addr_of($place:expr) {'
         pub use reexports::addr_of;
-        // @has 'foo/outer/inner/macro.addr_of_crate.html' '//*[@class="docblock item-decl"]' 'pub(crate) macro addr_of_crate($place:expr) {'
+        // @has 'foo/outer/inner/macro.addr_of_crate.html' '//*[@class="item-decl"]' 'pub(crate) macro addr_of_crate($place:expr) {'
         pub(crate) use reexports::addr_of_crate;
-        // @has 'foo/outer/inner/macro.addr_of_super.html' '//*[@class="docblock item-decl"]' 'pub(in outer) macro addr_of_super($place:expr) {'
+        // @has 'foo/outer/inner/macro.addr_of_super.html' '//*[@class="item-decl"]' 'pub(in outer) macro addr_of_super($place:expr) {'
         pub(super) use reexports::addr_of_super;
         // @!has 'foo/outer/inner/macro.addr_of_self.html'
         pub(self) use reexports::addr_of_self;
         // @!has 'foo/outer/inner/macro.addr_of_local.html'
         use reexports::addr_of_local;
 
-        // @has 'foo/outer/inner/struct.Foo.html' '//*[@class="docblock item-decl"]' 'pub struct Foo;'
+        // @has 'foo/outer/inner/struct.Foo.html' '//*[@class="item-decl"]' 'pub struct Foo;'
         pub use reexports::Foo;
-        // @has 'foo/outer/inner/struct.FooCrate.html' '//*[@class="docblock item-decl"]' 'pub(crate) struct FooCrate;'
+        // @has 'foo/outer/inner/struct.FooCrate.html' '//*[@class="item-decl"]' 'pub(crate) struct FooCrate;'
         pub(crate) use reexports::FooCrate;
-        // @has 'foo/outer/inner/struct.FooSuper.html' '//*[@class="docblock item-decl"]' 'pub(in outer) struct FooSuper;'
+        // @has 'foo/outer/inner/struct.FooSuper.html' '//*[@class="item-decl"]' 'pub(in outer) struct FooSuper;'
         pub(super) use reexports::FooSuper;
         // @!has 'foo/outer/inner/struct.FooSelf.html'
         pub(self) use reexports::FooSelf;
         // @!has 'foo/outer/inner/struct.FooLocal.html'
         use reexports::FooLocal;
 
-        // @has 'foo/outer/inner/enum.Bar.html' '//*[@class="docblock item-decl"]' 'pub enum Bar {'
+        // @has 'foo/outer/inner/enum.Bar.html' '//*[@class="item-decl"]' 'pub enum Bar {'
         pub use reexports::Bar;
-        // @has 'foo/outer/inner/enum.BarCrate.html' '//*[@class="docblock item-decl"]' 'pub(crate) enum BarCrate {'
+        // @has 'foo/outer/inner/enum.BarCrate.html' '//*[@class="item-decl"]' 'pub(crate) enum BarCrate {'
         pub(crate) use reexports::BarCrate;
-        // @has 'foo/outer/inner/enum.BarSuper.html' '//*[@class="docblock item-decl"]' 'pub(in outer) enum BarSuper {'
+        // @has 'foo/outer/inner/enum.BarSuper.html' '//*[@class="item-decl"]' 'pub(in outer) enum BarSuper {'
         pub(super) use reexports::BarSuper;
         // @!has 'foo/outer/inner/enum.BarSelf.html'
         pub(self) use reexports::BarSelf;
@@ -116,11 +116,11 @@ pub mod outer {
         // @!has 'foo/outer/inner/type.TypeLocal.html'
         use reexports::TypeLocal;
 
-        // @has 'foo/outer/inner/union.Union.html' '//*[@class="docblock item-decl"]' 'pub union Union {'
+        // @has 'foo/outer/inner/union.Union.html' '//*[@class="item-decl"]' 'pub union Union {'
         pub use reexports::Union;
-        // @has 'foo/outer/inner/union.UnionCrate.html' '//*[@class="docblock item-decl"]' 'pub(crate) union UnionCrate {'
+        // @has 'foo/outer/inner/union.UnionCrate.html' '//*[@class="item-decl"]' 'pub(crate) union UnionCrate {'
         pub(crate) use reexports::UnionCrate;
-        // @has 'foo/outer/inner/union.UnionSuper.html' '//*[@class="docblock item-decl"]' 'pub(in outer) union UnionSuper {'
+        // @has 'foo/outer/inner/union.UnionSuper.html' '//*[@class="item-decl"]' 'pub(in outer) union UnionSuper {'
         pub(super) use reexports::UnionSuper;
         // @!has 'foo/outer/inner/union.UnionSelf.html'
         pub(self) use reexports::UnionSelf;
diff --git a/src/test/rustdoc/reexports.rs b/src/test/rustdoc/reexports.rs
index 7abcbfb61812..9aa6d7224bac 100644
--- a/src/test/rustdoc/reexports.rs
+++ b/src/test/rustdoc/reexports.rs
@@ -4,7 +4,7 @@
 
 extern crate reexports;
 
-// @has 'foo/macro.addr_of.html' '//*[@class="docblock item-decl"]' 'pub macro addr_of($place:expr) {'
+// @has 'foo/macro.addr_of.html' '//*[@class="item-decl"]' 'pub macro addr_of($place:expr) {'
 pub use reexports::addr_of;
 // @!has 'foo/macro.addr_of_crate.html'
 pub(crate) use reexports::addr_of_crate;
@@ -13,7 +13,7 @@ pub(self) use reexports::addr_of_self;
 // @!has 'foo/macro.addr_of_local.html'
 use reexports::addr_of_local;
 
-// @has 'foo/struct.Foo.html' '//*[@class="docblock item-decl"]' 'pub struct Foo;'
+// @has 'foo/struct.Foo.html' '//*[@class="item-decl"]' 'pub struct Foo;'
 pub use reexports::Foo;
 // @!has 'foo/struct.FooCrate.html'
 pub(crate) use reexports::FooCrate;
@@ -22,7 +22,7 @@ pub(self) use reexports::FooSelf;
 // @!has 'foo/struct.FooLocal.html'
 use reexports::FooLocal;
 
-// @has 'foo/enum.Bar.html' '//*[@class="docblock item-decl"]' 'pub enum Bar {'
+// @has 'foo/enum.Bar.html' '//*[@class="item-decl"]' 'pub enum Bar {'
 pub use reexports::Bar;
 // @!has 'foo/enum.BarCrate.html'
 pub(crate) use reexports::BarCrate;
@@ -49,7 +49,7 @@ pub(self) use reexports::TypeSelf;
 // @!has 'foo/type.TypeLocal.html'
 use reexports::TypeLocal;
 
-// @has 'foo/union.Union.html' '//*[@class="docblock item-decl"]' 'pub union Union {'
+// @has 'foo/union.Union.html' '//*[@class="item-decl"]' 'pub union Union {'
 pub use reexports::Union;
 // @!has 'foo/union.UnionCrate.html'
 pub(crate) use reexports::UnionCrate;
@@ -60,7 +60,7 @@ use reexports::UnionLocal;
 
 pub mod outer {
     pub mod inner {
-        // @has 'foo/outer/inner/macro.addr_of.html' '//*[@class="docblock item-decl"]' 'pub macro addr_of($place:expr) {'
+        // @has 'foo/outer/inner/macro.addr_of.html' '//*[@class="item-decl"]' 'pub macro addr_of($place:expr) {'
         pub use reexports::addr_of;
         // @!has 'foo/outer/inner/macro.addr_of_crate.html'
         pub(crate) use reexports::addr_of_crate;
@@ -71,7 +71,7 @@ pub mod outer {
         // @!has 'foo/outer/inner/macro.addr_of_local.html'
         use reexports::addr_of_local;
 
-        // @has 'foo/outer/inner/struct.Foo.html' '//*[@class="docblock item-decl"]' 'pub struct Foo;'
+        // @has 'foo/outer/inner/struct.Foo.html' '//*[@class="item-decl"]' 'pub struct Foo;'
         pub use reexports::Foo;
         // @!has 'foo/outer/inner/struct.FooCrate.html'
         pub(crate) use reexports::FooCrate;
@@ -82,7 +82,7 @@ pub mod outer {
         // @!has 'foo/outer/inner/struct.FooLocal.html'
         use reexports::FooLocal;
 
-        // @has 'foo/outer/inner/enum.Bar.html' '//*[@class="docblock item-decl"]' 'pub enum Bar {'
+        // @has 'foo/outer/inner/enum.Bar.html' '//*[@class="item-decl"]' 'pub enum Bar {'
         pub use reexports::Bar;
         // @!has 'foo/outer/inner/enum.BarCrate.html'
         pub(crate) use reexports::BarCrate;
@@ -115,7 +115,7 @@ pub mod outer {
         // @!has 'foo/outer/inner/type.TypeLocal.html'
         use reexports::TypeLocal;
 
-        // @has 'foo/outer/inner/union.Union.html' '//*[@class="docblock item-decl"]' 'pub union Union {'
+        // @has 'foo/outer/inner/union.Union.html' '//*[@class="item-decl"]' 'pub union Union {'
         pub use reexports::Union;
         // @!has 'foo/outer/inner/union.UnionCrate.html'
         pub(crate) use reexports::UnionCrate;
diff --git a/src/test/rustdoc/rfc-2632-const-trait-impl.rs b/src/test/rustdoc/rfc-2632-const-trait-impl.rs
index f3e211e30174..8bd402291aab 100644
--- a/src/test/rustdoc/rfc-2632-const-trait-impl.rs
+++ b/src/test/rustdoc/rfc-2632-const-trait-impl.rs
@@ -30,10 +30,10 @@ pub trait Tr<T> {
 }
 
 // @has - '//section[@id="impl-Tr%3CT%3E-for-T"]' ''
-// @!has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]' '~const'
-// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]/a[@class="trait"]' 'Clone'
-// @!has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]/span[@class="where"]' '~const'
-// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]/span[@class="where fmt-newline"]' ': Clone'
+// @!has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header"]' '~const'
+// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header"]/a[@class="trait"]' 'Clone'
+// @!has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header"]/span[@class="where"]' '~const'
+// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header"]/span[@class="where fmt-newline"]' ': Clone'
 impl<T: ~const Clone + ~const Destruct> const Tr<T> for T
 where
     Option<T>: ~const Clone + ~const Destruct,
diff --git a/src/test/rustdoc/short-docblock.rs b/src/test/rustdoc/short-docblock.rs
index 17c44eab091a..1a8a689be1d1 100644
--- a/src/test/rustdoc/short-docblock.rs
+++ b/src/test/rustdoc/short-docblock.rs
@@ -1,7 +1,7 @@
 #![crate_name = "foo"]
 
-// @has foo/index.html '//*[@class="item-right docblock-short"]/p' 'fooo'
-// @!has foo/index.html '//*[@class="item-right docblock-short"]/p/h1' 'fooo'
+// @has foo/index.html '//*[@class="item-right docblock-short"]' 'fooo'
+// @!has foo/index.html '//*[@class="item-right docblock-short"]/h1' 'fooo'
 // @has foo/fn.foo.html '//h2[@id="fooo"]/a[@href="#fooo"]' 'fooo'
 
 /// # fooo
@@ -9,8 +9,8 @@
 /// foo
 pub fn foo() {}
 
-// @has foo/index.html '//*[@class="item-right docblock-short"]/p' 'mooood'
-// @!has foo/index.html '//*[@class="item-right docblock-short"]/p/h2' 'mooood'
+// @has foo/index.html '//*[@class="item-right docblock-short"]' 'mooood'
+// @!has foo/index.html '//*[@class="item-right docblock-short"]/h2' 'mooood'
 // @has foo/foo/index.html '//h3[@id="mooood"]/a[@href="#mooood"]' 'mooood'
 
 /// ## mooood
@@ -18,7 +18,7 @@ pub fn foo() {}
 /// foo mod
 pub mod foo {}
 
-// @has foo/index.html '//*[@class="item-right docblock-short"]/p/a[@href=\
+// @has foo/index.html '//*[@class="item-right docblock-short"]/a[@href=\
 //                      "https://nougat.world"]/code' 'nougat'
 
 /// [`nougat`](https://nougat.world)
diff --git a/src/test/rustdoc/sidebar-all-page.rs b/src/test/rustdoc/sidebar-all-page.rs
new file mode 100644
index 000000000000..e74b981de644
--- /dev/null
+++ b/src/test/rustdoc/sidebar-all-page.rs
@@ -0,0 +1,35 @@
+#![crate_name = "foo"]
+
+#![feature(rustdoc_internals)]
+
+// @has 'foo/all.html'
+// @has - '//*[@class="sidebar-elems"]//li' 'Structs'
+// @has - '//*[@class="sidebar-elems"]//li' 'Enums'
+// @has - '//*[@class="sidebar-elems"]//li' 'Unions'
+// @has - '//*[@class="sidebar-elems"]//li' 'Functions'
+// @has - '//*[@class="sidebar-elems"]//li' 'Traits'
+// @has - '//*[@class="sidebar-elems"]//li' 'Macros'
+// @has - '//*[@class="sidebar-elems"]//li' 'Type Definitions'
+// @has - '//*[@class="sidebar-elems"]//li' 'Constants'
+// @has - '//*[@class="sidebar-elems"]//li' 'Statics'
+// @has - '//*[@class="sidebar-elems"]//li' 'Primitive Types'
+
+pub struct Foo;
+pub enum Enum {
+    A,
+}
+pub union Bar {
+    a: u8,
+    b: u16,
+}
+pub fn foo() {}
+pub trait Trait {}
+#[macro_export]
+macro_rules! foo {
+    () => {}
+}
+pub type Type = u8;
+pub const FOO: u8 = 0;
+pub static BAR: u8 = 0;
+#[doc(primitive = "u8")]
+mod u8 {}
diff --git a/src/test/rustdoc/sidebar-links-to-foreign-impl.rs b/src/test/rustdoc/sidebar-links-to-foreign-impl.rs
index 155150396599..6712af527a37 100644
--- a/src/test/rustdoc/sidebar-links-to-foreign-impl.rs
+++ b/src/test/rustdoc/sidebar-links-to-foreign-impl.rs
@@ -6,9 +6,9 @@
 // @has - '//*[@class="sidebar-title"]/a[@href="#foreign-impls"]' 'Implementations on Foreign Types'
 // @has - '//h2[@id="foreign-impls"]' 'Implementations on Foreign Types'
 // @has - '//*[@class="sidebar-elems"]//section//a[@href="#impl-Foo-for-u32"]' 'u32'
-// @has - '//*[@id="impl-Foo-for-u32"]//h3[@class="code-header in-band"]' 'impl Foo for u32'
+// @has - '//*[@id="impl-Foo-for-u32"]//h3[@class="code-header"]' 'impl Foo for u32'
 // @has - '//*[@class="sidebar-elems"]//section//a[@href="#impl-Foo-for-%26%27a%20str"]' "&'a str"
-// @has - '//*[@id="impl-Foo-for-%26%27a%20str"]//h3[@class="code-header in-band"]' "impl<'a> Foo for &'a str"
+// @has - '//*[@id="impl-Foo-for-%26%27a%20str"]//h3[@class="code-header"]' "impl<'a> Foo for &'a str"
 pub trait Foo {}
 
 impl Foo for u32 {}
diff --git a/src/test/rustdoc/sized_trait.rs b/src/test/rustdoc/sized_trait.rs
index 36718ebe1a63..feef4de8d57f 100644
--- a/src/test/rustdoc/sized_trait.rs
+++ b/src/test/rustdoc/sized_trait.rs
@@ -11,7 +11,7 @@ pub struct Bar {
 pub struct Foo<T: ?Sized>(T);
 
 // @has foo/struct.Unsized.html
-// @has - '//*[@id="impl-Sized-for-Unsized"]//h3[@class="code-header in-band"]' 'impl !Sized for Unsized'
+// @has - '//*[@id="impl-Sized-for-Unsized"]//h3[@class="code-header"]' 'impl !Sized for Unsized'
 pub struct Unsized {
     data: [u8],
 }
diff --git a/src/test/rustdoc/src-links-auto-impls.rs b/src/test/rustdoc/src-links-auto-impls.rs
index 313a4b118933..953563833c9c 100644
--- a/src/test/rustdoc/src-links-auto-impls.rs
+++ b/src/test/rustdoc/src-links-auto-impls.rs
@@ -1,11 +1,11 @@
 #![crate_name = "foo"]
 
 // @has foo/struct.Unsized.html
-// @has - '//*[@id="impl-Sized-for-Unsized"]/h3[@class="code-header in-band"]' 'impl !Sized for Unsized'
+// @has - '//*[@id="impl-Sized-for-Unsized"]/h3[@class="code-header"]' 'impl !Sized for Unsized'
 // @!has - '//*[@id="impl-Sized-for-Unsized"]//a[@class="srclink"]' 'source'
-// @has - '//*[@id="impl-Sync-for-Unsized"]/h3[@class="code-header in-band"]' 'impl Sync for Unsized'
+// @has - '//*[@id="impl-Sync-for-Unsized"]/h3[@class="code-header"]' 'impl Sync for Unsized'
 // @!has - '//*[@id="impl-Sync-for-Unsized"]//a[@class="srclink"]' 'source'
-// @has - '//*[@id="impl-Any-for-Unsized"]/h3[@class="code-header in-band"]' 'impl<T> Any for T'
+// @has - '//*[@id="impl-Any-for-Unsized"]/h3[@class="code-header"]' 'impl<T> Any for T'
 // @has - '//*[@id="impl-Any-for-Unsized"]//a[@class="srclink rightside"]' 'source'
 pub struct Unsized {
     data: [u8],
diff --git a/src/test/rustdoc/synthetic_auto/basic.rs b/src/test/rustdoc/synthetic_auto/basic.rs
index 54c54fdbf68a..7c6a388653c4 100644
--- a/src/test/rustdoc/synthetic_auto/basic.rs
+++ b/src/test/rustdoc/synthetic_auto/basic.rs
@@ -1,6 +1,6 @@
 // @has basic/struct.Foo.html
-// @has - '//h3[@class="code-header in-band"]' 'impl<T> Send for Foo<T> where T: Send'
-// @has - '//h3[@class="code-header in-band"]' 'impl<T> Sync for Foo<T> where T: Sync'
+// @has - '//h3[@class="code-header"]' 'impl<T> Send for Foo<T>where T: Send'
+// @has - '//h3[@class="code-header"]' 'impl<T> Sync for Foo<T>where T: Sync'
 // @count - '//*[@id="implementations-list"]//*[@class="impl has-srclink"]' 0
 // @count - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]' 5
 pub struct Foo<T> {
diff --git a/src/test/rustdoc/synthetic_auto/complex.rs b/src/test/rustdoc/synthetic_auto/complex.rs
index f9017b90caee..43393c21fddb 100644
--- a/src/test/rustdoc/synthetic_auto/complex.rs
+++ b/src/test/rustdoc/synthetic_auto/complex.rs
@@ -20,8 +20,8 @@ mod foo {
 }
 
 // @has complex/struct.NotOuter.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'a, T, K: ?Sized> Send for Outer<'a, T, K> where K: for<'b> Fn((&'b bool, &'a u8)) \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'a, T, K: ?Sized> Send for Outer<'a, T, K>where K: for<'b> Fn((&'b bool, &'a u8)) \
 // -> &'b i8, T: MyTrait<'a>, <T as MyTrait<'a>>::MyItem: Copy, 'a: 'static"
 
 pub use foo::{Foo, Inner as NotInner, MyTrait as NotMyTrait, Outer as NotOuter};
diff --git a/src/test/rustdoc/synthetic_auto/crate-local.rs b/src/test/rustdoc/synthetic_auto/crate-local.rs
index 58b787dfafc7..ed01f63f998b 100644
--- a/src/test/rustdoc/synthetic_auto/crate-local.rs
+++ b/src/test/rustdoc/synthetic_auto/crate-local.rs
@@ -3,7 +3,7 @@
 pub auto trait Banana {}
 
 // @has crate_local/struct.Peach.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Banana for Peach'
-// @has - '//h3[@class="code-header in-band"]' 'impl Send for Peach'
-// @has - '//h3[@class="code-header in-band"]' 'impl Sync for Peach'
+// @has - '//h3[@class="code-header"]' 'impl Banana for Peach'
+// @has - '//h3[@class="code-header"]' 'impl Send for Peach'
+// @has - '//h3[@class="code-header"]' 'impl Sync for Peach'
 pub struct Peach;
diff --git a/src/test/rustdoc/synthetic_auto/lifetimes.rs b/src/test/rustdoc/synthetic_auto/lifetimes.rs
index ee1393f9729c..33170a844359 100644
--- a/src/test/rustdoc/synthetic_auto/lifetimes.rs
+++ b/src/test/rustdoc/synthetic_auto/lifetimes.rs
@@ -9,11 +9,11 @@ where
 {}
 
 // @has lifetimes/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'c, K> Send for Foo<'c, K> where K: for<'b> Fn(&'b bool) -> &'c u8, 'c: 'static"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'c, K> Send for Foo<'c, K>where K: for<'b> Fn(&'b bool) -> &'c u8, 'c: 'static"
 //
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'c, K> Sync for Foo<'c, K> where K: Sync"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'c, K> Sync for Foo<'c, K>where K: Sync"
 pub struct Foo<'c, K: 'c> {
     inner_field: Inner<'c, K>,
 }
diff --git a/src/test/rustdoc/synthetic_auto/manual.rs b/src/test/rustdoc/synthetic_auto/manual.rs
index 49bad162211b..77c04ad2ad94 100644
--- a/src/test/rustdoc/synthetic_auto/manual.rs
+++ b/src/test/rustdoc/synthetic_auto/manual.rs
@@ -1,8 +1,8 @@
 // @has manual/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// 'impl<T> Sync for Foo<T> where T: Sync'
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// 'impl<T> Sync for Foo<T>where T: Sync'
 //
-// @has - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // 'impl<T> Send for Foo<T>'
 //
 // @count - '//*[@id="trait-implementations-list"]//*[@class="impl has-srclink"]' 1
diff --git a/src/test/rustdoc/synthetic_auto/negative.rs b/src/test/rustdoc/synthetic_auto/negative.rs
index 66e749ac38d9..2c2c848a5e0f 100644
--- a/src/test/rustdoc/synthetic_auto/negative.rs
+++ b/src/test/rustdoc/synthetic_auto/negative.rs
@@ -3,10 +3,10 @@ pub struct Inner<T: Copy> {
 }
 
 // @has negative/struct.Outer.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<T> !Send for Outer<T>"
 //
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
 // "impl<T> !Sync for Outer<T>"
 pub struct Outer<T: Copy> {
     inner_field: Inner<T>,
diff --git a/src/test/rustdoc/synthetic_auto/nested.rs b/src/test/rustdoc/synthetic_auto/nested.rs
index 69edbee619e3..423bf115ab16 100644
--- a/src/test/rustdoc/synthetic_auto/nested.rs
+++ b/src/test/rustdoc/synthetic_auto/nested.rs
@@ -9,11 +9,11 @@ where
 }
 
 // @has nested/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// 'impl<T> Send for Foo<T> where T: Copy'
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// 'impl<T> Send for Foo<T>where T: Copy'
 //
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// 'impl<T> Sync for Foo<T> where T: Sync'
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// 'impl<T> Sync for Foo<T>where T: Sync'
 pub struct Foo<T> {
     inner_field: Inner<T>,
 }
diff --git a/src/test/rustdoc/synthetic_auto/no-redundancy.rs b/src/test/rustdoc/synthetic_auto/no-redundancy.rs
index 16ab876e829e..59f33623322a 100644
--- a/src/test/rustdoc/synthetic_auto/no-redundancy.rs
+++ b/src/test/rustdoc/synthetic_auto/no-redundancy.rs
@@ -9,8 +9,8 @@ where
 }
 
 // @has no_redundancy/struct.Outer.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<T> Send for Outer<T> where T: Send + Copy"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<T> Send for Outer<T>where T: Send + Copy"
 pub struct Outer<T> {
     inner_field: Inner<T>,
 }
diff --git a/src/test/rustdoc/synthetic_auto/overflow.rs b/src/test/rustdoc/synthetic_auto/overflow.rs
index c132ab6fb1b3..35a487c764dc 100644
--- a/src/test/rustdoc/synthetic_auto/overflow.rs
+++ b/src/test/rustdoc/synthetic_auto/overflow.rs
@@ -21,7 +21,7 @@ enum TyData<I: Interner> {
 struct VariableKind<I: Interner>(I::InternedType);
 
 // @has overflow/struct.BoundVarsCollector.html
-// @has - '//h3[@class="code-header in-band"]' "impl<'tcx> Send for BoundVarsCollector<'tcx>"
+// @has - '//h3[@class="code-header"]' "impl<'tcx> Send for BoundVarsCollector<'tcx>"
 pub struct BoundVarsCollector<'tcx> {
     val: VariableKind<RustInterner<'tcx>>
 }
diff --git a/src/test/rustdoc/synthetic_auto/project.rs b/src/test/rustdoc/synthetic_auto/project.rs
index 8b020582563f..558ff2add400 100644
--- a/src/test/rustdoc/synthetic_auto/project.rs
+++ b/src/test/rustdoc/synthetic_auto/project.rs
@@ -23,11 +23,11 @@ where
 }
 
 // @has project/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'c, K> Send for Foo<'c, K> where K: MyTrait<MyItem = bool>, 'c: 'static"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'c, K> Send for Foo<'c, K>where K: MyTrait<MyItem = bool>, 'c: 'static"
 //
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<'c, K> Sync for Foo<'c, K> where K: MyTrait, <K as MyTrait>::MyItem: OtherTrait, \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<'c, K> Sync for Foo<'c, K>where K: MyTrait, <K as MyTrait>::MyItem: OtherTrait, \
 // 'c: 'static,"
 pub struct Foo<'c, K: 'c> {
     inner_field: Inner<'c, K>,
diff --git a/src/test/rustdoc/synthetic_auto/self-referential.rs b/src/test/rustdoc/synthetic_auto/self-referential.rs
index ccef901b18da..c6ae96de7767 100644
--- a/src/test/rustdoc/synthetic_auto/self-referential.rs
+++ b/src/test/rustdoc/synthetic_auto/self-referential.rs
@@ -23,7 +23,7 @@ impl<T> Pattern for Wrapper<T> {
 
 
 // @has self_referential/struct.WriteAndThen.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<P1> Send for WriteAndThen<P1>  where  <P1 as Pattern>::Value: Send"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<P1> Send for WriteAndThen<P1>where    <P1 as Pattern>::Value: Send"
 pub struct WriteAndThen<P1>(pub P1::Value,pub <Constrain<P1, Wrapper<P1::Value>> as Pattern>::Value)
     where P1: Pattern;
diff --git a/src/test/rustdoc/synthetic_auto/static-region.rs b/src/test/rustdoc/synthetic_auto/static-region.rs
index 36e985144b0e..1a76cb919c29 100644
--- a/src/test/rustdoc/synthetic_auto/static-region.rs
+++ b/src/test/rustdoc/synthetic_auto/static-region.rs
@@ -3,8 +3,8 @@ pub trait OwnedTrait<'a> {
 }
 
 // @has static_region/struct.Owned.html
-// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-// "impl<T> Send for Owned<T> where <T as OwnedTrait<'static>>::Reader: Send"
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+// "impl<T> Send for Owned<T>where <T as OwnedTrait<'static>>::Reader: Send"
 pub struct Owned<T> where T: OwnedTrait<'static> {
     marker: <T as OwnedTrait<'static>>::Reader,
 }
diff --git a/src/test/rustdoc/toggle-item-contents.rs b/src/test/rustdoc/toggle-item-contents.rs
index dbaf195e1a96..47a1d62f5a7a 100644
--- a/src/test/rustdoc/toggle-item-contents.rs
+++ b/src/test/rustdoc/toggle-item-contents.rs
@@ -55,7 +55,7 @@ pub union Union {
 
 // @has 'toggle_item_contents/struct.PrivStruct.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 0
-// @has - '//div[@class="docblock item-decl"]' '/* private fields */'
+// @has - '//div[@class="item-decl"]' '/* private fields */'
 pub struct PrivStruct {
     a: usize,
     b: usize,
diff --git a/src/test/rustdoc/trait-impl.rs b/src/test/rustdoc/trait-impl.rs
index 4d5173f6024c..195cdf009b99 100644
--- a/src/test/rustdoc/trait-impl.rs
+++ b/src/test/rustdoc/trait-impl.rs
@@ -21,26 +21,26 @@ pub trait Trait {
 pub struct Struct;
 
 impl Trait for Struct {
-    // @has trait_impl/struct.Struct.html '//*[@id="method.a"]/../../div[@class="docblock"]/p' 'Some long docs'
-    // @!has - '//*[@id="method.a"]/../../div[@class="docblock"]/p' 'link will be added'
-    // @has - '//*[@id="method.a"]/../../div[@class="docblock"]/p/a' 'Read more'
-    // @has - '//*[@id="method.a"]/../../div[@class="docblock"]/p/a/@href' 'trait.Trait.html#tymethod.a'
+    // @has trait_impl/struct.Struct.html '//*[@id="method.a"]/../../div[@class="docblock"]' 'Some long docs'
+    // @!has - '//*[@id="method.a"]/../../div[@class="docblock"]' 'link will be added'
+    // @has - '//*[@id="method.a"]/../../div[@class="docblock"]/a' 'Read more'
+    // @has - '//*[@id="method.a"]/../../div[@class="docblock"]/a/@href' 'trait.Trait.html#tymethod.a'
     fn a() {}
 
-    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/p' 'These docs contain'
-    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/p/a' 'reference link'
-    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/p/a/@href' 'https://example.com'
-    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/p/a' 'Read more'
-    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/p/a/@href' 'trait.Trait.html#tymethod.b'
+    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]' 'These docs contain'
+    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/a' 'reference link'
+    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/a/@href' 'https://example.com'
+    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/a' 'Read more'
+    // @has - '//*[@id="method.b"]/../../div[@class="docblock"]/a/@href' 'trait.Trait.html#tymethod.b'
     fn b() {}
 
-    // @!has - '//*[@id="method.c"]/../../div[@class="docblock"]/p' 'code block'
+    // @!has - '//*[@id="method.c"]/../../div[@class="docblock"]' 'code block'
     // @has - '//*[@id="method.c"]/../../div[@class="docblock"]/a' 'Read more'
     // @has - '//*[@id="method.c"]/../../div[@class="docblock"]/a/@href' 'trait.Trait.html#tymethod.c'
     fn c() {}
 
-    // @has - '//*[@id="method.d"]/../../div[@class="docblock"]/p' 'Escaped formatting a*b*c* works'
-    // @!has - '//*[@id="method.d"]/../../div[@class="docblock"]/p/em' ''
+    // @has - '//*[@id="method.d"]/../../div[@class="docblock"]' 'Escaped formatting a*b*c* works'
+    // @!has - '//*[@id="method.d"]/../../div[@class="docblock"]/em' ''
     fn d() {}
 
     // @has - '//*[@id="impl-Trait-for-Struct"]/h3//a/@href' 'trait.Trait.html'
diff --git a/src/test/rustdoc/trait_alias.rs b/src/test/rustdoc/trait_alias.rs
index a0c657d9a054..791c099cc523 100644
--- a/src/test/rustdoc/trait_alias.rs
+++ b/src/test/rustdoc/trait_alias.rs
@@ -14,13 +14,13 @@ use std::fmt::Debug;
 // @has foo/index.html '//a[@class="traitalias"]' 'Foo'
 
 // @has foo/traitalias.CopyAlias.html
-// @has - '//section[@id="main-content"]/div[@class="docblock item-decl"]/pre' 'trait CopyAlias = Copy;'
+// @has - '//section[@id="main-content"]/div[@class="item-decl"]/pre' 'trait CopyAlias = Copy;'
 pub trait CopyAlias = Copy;
 // @has foo/traitalias.Alias2.html
-// @has - '//section[@id="main-content"]/div[@class="docblock item-decl"]/pre' 'trait Alias2 = Copy + Debug;'
+// @has - '//section[@id="main-content"]/div[@class="item-decl"]/pre' 'trait Alias2 = Copy + Debug;'
 pub trait Alias2 = Copy + Debug;
 // @has foo/traitalias.Foo.html
-// @has - '//section[@id="main-content"]/div[@class="docblock item-decl"]/pre' 'trait Foo<T> = Into<T> + Debug;'
+// @has - '//section[@id="main-content"]/div[@class="item-decl"]/pre' 'trait Foo<T> = Into<T> + Debug;'
 pub trait Foo<T> = Into<T> + Debug;
 // @has foo/fn.bar.html '//a[@href="traitalias.Alias2.html"]' 'Alias2'
 pub fn bar<T>() where T: Alias2 {}
diff --git a/src/test/rustdoc/traits-in-bodies.rs b/src/test/rustdoc/traits-in-bodies.rs
index 6d450a625d0b..a65dd7a546cd 100644
--- a/src/test/rustdoc/traits-in-bodies.rs
+++ b/src/test/rustdoc/traits-in-bodies.rs
@@ -4,7 +4,7 @@
 pub struct Bounded<T: Clone>(T);
 
 // @has traits_in_bodies/struct.SomeStruct.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Clone for SomeStruct'
+// @has - '//h3[@class="code-header"]' 'impl Clone for SomeStruct'
 pub struct SomeStruct;
 
 fn asdf() -> Bounded<SomeStruct> {
@@ -18,7 +18,7 @@ fn asdf() -> Bounded<SomeStruct> {
 }
 
 // @has traits_in_bodies/struct.Point.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Copy for Point'
+// @has - '//h3[@class="code-header"]' 'impl Copy for Point'
 #[derive(Clone)]
 pub struct Point {
     x: i32,
@@ -31,7 +31,7 @@ const _FOO: () = {
 };
 
 // @has traits_in_bodies/struct.Inception.html
-// @has - '//h3[@class="code-header in-band"]' 'impl Clone for Inception'
+// @has - '//h3[@class="code-header"]' 'impl Clone for Inception'
 pub struct Inception;
 
 static _BAR: usize = {
diff --git a/src/test/rustdoc/typedef.rs b/src/test/rustdoc/typedef.rs
index b68ec4557ad5..d5dfa9484891 100644
--- a/src/test/rustdoc/typedef.rs
+++ b/src/test/rustdoc/typedef.rs
@@ -9,8 +9,8 @@ impl MyStruct {
 }
 
 // @has typedef/type.MyAlias.html
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'impl MyAlias'
-// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' 'impl MyTrait for MyAlias'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'impl MyAlias'
+// @has - '//*[@class="impl has-srclink"]//h3[@class="code-header"]' 'impl MyTrait for MyAlias'
 // @hasraw - 'Alias docstring'
 // @has - '//*[@class="sidebar"]//*[@class="location"]' 'MyAlias'
 // @has - '//*[@class="sidebar"]//a[@href="#implementations"]' 'Methods'
diff --git a/src/test/rustdoc/where-clause-order.rs b/src/test/rustdoc/where-clause-order.rs
index 3150a8ea05f4..b8502e10a48c 100644
--- a/src/test/rustdoc/where-clause-order.rs
+++ b/src/test/rustdoc/where-clause-order.rs
@@ -7,7 +7,7 @@ where
 }
 
 // @has 'foo/trait.SomeTrait.html'
-// @has - "//*[@id='impl-SomeTrait%3C(A%2C%20B%2C%20C%2C%20D%2C%20E)%3E-for-(A%2C%20B%2C%20C%2C%20D%2C%20E)']/h3" "impl<A, B, C, D, E> SomeTrait<(A, B, C, D, E)> for (A, B, C, D, E) where A: PartialOrd<A> + PartialEq<A>, B: PartialOrd<B> + PartialEq<B>, C: PartialOrd<C> + PartialEq<C>, D: PartialOrd<D> + PartialEq<D>, E: PartialOrd<E> + PartialEq<E> + ?Sized, "
+// @has - "//*[@id='impl-SomeTrait%3C(A%2C%20B%2C%20C%2C%20D%2C%20E)%3E-for-(A%2C%20B%2C%20C%2C%20D%2C%20E)']/h3" "impl<A, B, C, D, E> SomeTrait<(A, B, C, D, E)> for (A, B, C, D, E)where A: PartialOrd<A> + PartialEq<A>, B: PartialOrd<B> + PartialEq<B>, C: PartialOrd<C> + PartialEq<C>, D: PartialOrd<D> + PartialEq<D>, E: PartialOrd<E> + PartialEq<E> + ?Sized, "
 impl<A, B, C, D, E> SomeTrait<(A, B, C, D, E)> for (A, B, C, D, E)
 where
     A: PartialOrd<A> + PartialEq<A>,
diff --git a/src/test/rustdoc/where.SWhere_Simd_item-decl.html b/src/test/rustdoc/where.SWhere_Simd_item-decl.html
index 0133bcaeb667..6c1b5d315135 100644
--- a/src/test/rustdoc/where.SWhere_Simd_item-decl.html
+++ b/src/test/rustdoc/where.SWhere_Simd_item-decl.html
@@ -1 +1 @@
-<div class="docblock item-decl"><pre class="rust struct"><code>pub struct Simd&lt;T&gt;(_) <br /><span class="where">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="trait.MyTrait.html" title="trait foo::MyTrait">MyTrait</a></span>;</code></pre></div>
\ No newline at end of file
+<div class="item-decl"><pre class="rust struct"><code>pub struct Simd&lt;T&gt;(_)<br /><span class="where">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="trait.MyTrait.html" title="trait foo::MyTrait">MyTrait</a></span>;</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/where.SWhere_TraitWhere_item-decl.html b/src/test/rustdoc/where.SWhere_TraitWhere_item-decl.html
index 54026ff034e0..24ab77703d10 100644
--- a/src/test/rustdoc/where.SWhere_TraitWhere_item-decl.html
+++ b/src/test/rustdoc/where.SWhere_TraitWhere_item-decl.html
@@ -1,3 +1,8 @@
-<div class="docblock item-decl"><pre class="rust trait"><code>pub trait TraitWhere {
-    type <a href="#associatedtype.Item" class="associatedtype">Item</a>&lt;'a&gt;<br />&#160;&#160;&#160; <span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: 'a</span>;
+<div class="item-decl"><pre class="rust trait"><code>pub trait TraitWhere {
+    type <a href="#associatedtype.Item" class="associatedtype">Item</a>&lt;'a&gt;<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: 'a</span>;
+
+    fn <a href="#method.func" class="fnname">func</a>(self)<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span>,
+    { ... }
+<span class="item-spacer" />    fn <a href="#method.lines" class="fnname">lines</a>(self) -&gt; <a class="struct" href="{{channel}}/std/io/struct.Lines.html" title="struct std::io::Lines">Lines</a>&lt;Self&gt;<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span>,
+    { ... }
 }</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/where.rs b/src/test/rustdoc/where.rs
index 50a5722fbaff..8b5bce28f5a2 100644
--- a/src/test/rustdoc/where.rs
+++ b/src/test/rustdoc/where.rs
@@ -1,19 +1,20 @@
-#![feature(generic_associated_types)]
 #![crate_name = "foo"]
 
+use std::io::Lines;
+
 pub trait MyTrait { fn dummy(&self) { } }
 
-// @has foo/struct.Alpha.html '//pre' "pub struct Alpha<A>(_) where A: MyTrait"
+// @has foo/struct.Alpha.html '//pre' "pub struct Alpha<A>(_)where A: MyTrait"
 pub struct Alpha<A>(A) where A: MyTrait;
-// @has foo/trait.Bravo.html '//pre' "pub trait Bravo<B> where B: MyTrait"
+// @has foo/trait.Bravo.html '//pre' "pub trait Bravo<B>where B: MyTrait"
 pub trait Bravo<B> where B: MyTrait { fn get(&self, B: B); }
-// @has foo/fn.charlie.html '//pre' "pub fn charlie<C>() where C: MyTrait"
+// @has foo/fn.charlie.html '//pre' "pub fn charlie<C>()where C: MyTrait"
 pub fn charlie<C>() where C: MyTrait {}
 
 pub struct Delta<D>(D);
 
-// @has foo/struct.Delta.html '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-//          "impl<D> Delta<D> where D: MyTrait"
+// @has foo/struct.Delta.html '//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+//          "impl<D> Delta<D>where D: MyTrait"
 impl<D> Delta<D> where D: MyTrait {
     pub fn delta() {}
 }
@@ -21,31 +22,41 @@ impl<D> Delta<D> where D: MyTrait {
 pub struct Echo<E>(E);
 
 // @has 'foo/struct.Simd.html'
-// @snapshot SWhere_Simd_item-decl - '//div[@class="docblock item-decl"]'
+// @snapshot SWhere_Simd_item-decl - '//div[@class="item-decl"]'
 pub struct Simd<T>([T; 1])
 where
     T: MyTrait;
 
 // @has 'foo/trait.TraitWhere.html'
-// @snapshot SWhere_TraitWhere_item-decl - '//div[@class="docblock item-decl"]'
+// @snapshot SWhere_TraitWhere_item-decl - '//div[@class="item-decl"]'
 pub trait TraitWhere {
     type Item<'a> where Self: 'a;
+
+    fn func(self)
+    where
+        Self: Sized
+    {}
+
+    fn lines(self) -> Lines<Self>
+    where
+        Self: Sized,
+    { todo!() }
 }
 
-// @has foo/struct.Echo.html '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-//          "impl<E> MyTrait for Echo<E> where E: MyTrait"
-// @has foo/trait.MyTrait.html '//*[@id="implementors-list"]//h3[@class="code-header in-band"]' \
-//          "impl<E> MyTrait for Echo<E> where E: MyTrait"
-impl<E> MyTrait for Echo<E> where E: MyTrait {}
+// @has foo/struct.Echo.html '//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+//          "impl<E> MyTrait for Echo<E>where E: MyTrait"
+// @has foo/trait.MyTrait.html '//*[@id="implementors-list"]//h3[@class="code-header"]' \
+//          "impl<E> MyTrait for Echo<E>where E: MyTrait"
+impl<E> MyTrait for Echo<E>where E: MyTrait {}
 
 pub enum Foxtrot<F> { Foxtrot1(F) }
 
-// @has foo/enum.Foxtrot.html '//*[@class="impl has-srclink"]//h3[@class="code-header in-band"]' \
-//          "impl<F> MyTrait for Foxtrot<F> where F: MyTrait"
-// @has foo/trait.MyTrait.html '//*[@id="implementors-list"]//h3[@class="code-header in-band"]' \
-//          "impl<F> MyTrait for Foxtrot<F> where F: MyTrait"
-impl<F> MyTrait for Foxtrot<F> where F: MyTrait {}
+// @has foo/enum.Foxtrot.html '//*[@class="impl has-srclink"]//h3[@class="code-header"]' \
+//          "impl<F> MyTrait for Foxtrot<F>where F: MyTrait"
+// @has foo/trait.MyTrait.html '//*[@id="implementors-list"]//h3[@class="code-header"]' \
+//          "impl<F> MyTrait for Foxtrot<F>where F: MyTrait"
+impl<F> MyTrait for Foxtrot<F>where F: MyTrait {}
 
 // @has foo/type.Golf.html '//pre[@class="rust typedef"]' \
-//          "type Golf<T> where T: Clone, = (T, T)"
+//          "type Golf<T>where T: Clone, = (T, T)"
 pub type Golf<T> where T: Clone = (T, T);
diff --git a/src/test/rustdoc/whitespace-after-where-clause.enum.html b/src/test/rustdoc/whitespace-after-where-clause.enum.html
index 9e5bf45ae7d2..c74866f4a10b 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.enum.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.enum.html
@@ -1,4 +1,4 @@
-<div class="docblock item-decl"><pre class="rust enum"><code>pub enum Cow&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a&gt; <span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt;,&#160;</span>{
+<div class="item-decl"><pre class="rust enum"><code>pub enum Cow&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt;,</span>{
     Borrowed(<a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B),
     Whatever(<a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>),
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.enum2.html b/src/test/rustdoc/whitespace-after-where-clause.enum2.html
index 6bc47beaed12..ac7d77598211 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.enum2.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.enum2.html
@@ -1,4 +1,4 @@
-<div class="docblock item-decl"><pre class="rust enum"><code>pub enum Cow2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
+<div class="item-decl"><pre class="rust enum"><code>pub enum Cow2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
     Borrowed(<a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B),
     Whatever(<a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>),
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.rs b/src/test/rustdoc/whitespace-after-where-clause.rs
index c36386a2aa2b..4b740b970fc2 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.rs
+++ b/src/test/rustdoc/whitespace-after-where-clause.rs
@@ -4,7 +4,7 @@
 #![crate_name = "foo"]
 
 // @has 'foo/trait.ToOwned.html'
-// @snapshot trait - '//*[@class="docblock item-decl"]'
+// @snapshot trait - '//*[@class="item-decl"]'
 pub trait ToOwned<T>
 where T: Clone
 {
@@ -14,7 +14,7 @@ where T: Clone
 }
 
 // @has 'foo/trait.ToOwned2.html'
-// @snapshot trait2 - '//*[@class="docblock item-decl"]'
+// @snapshot trait2 - '//*[@class="item-decl"]'
 // There should be a whitespace before `{` in this case!
 pub trait ToOwned2<T: Clone> {
     type Owned;
@@ -23,7 +23,7 @@ pub trait ToOwned2<T: Clone> {
 }
 
 // @has 'foo/enum.Cow.html'
-// @snapshot enum - '//*[@class="docblock item-decl"]'
+// @snapshot enum - '//*[@class="item-decl"]'
 pub enum Cow<'a, B: ?Sized + 'a>
 where
     B: ToOwned<Clone>,
@@ -33,7 +33,7 @@ where
 }
 
 // @has 'foo/enum.Cow2.html'
-// @snapshot enum2 - '//*[@class="docblock item-decl"]'
+// @snapshot enum2 - '//*[@class="item-decl"]'
 // There should be a whitespace before `{` in this case!
 pub enum Cow2<'a, B: ?Sized + ToOwned<Clone> + 'a> {
     Borrowed(&'a B),
@@ -41,7 +41,7 @@ pub enum Cow2<'a, B: ?Sized + ToOwned<Clone> + 'a> {
 }
 
 // @has 'foo/struct.Struct.html'
-// @snapshot struct - '//*[@class="docblock item-decl"]'
+// @snapshot struct - '//*[@class="item-decl"]'
 pub struct Struct<'a, B: ?Sized + 'a>
 where
     B: ToOwned<Clone>,
@@ -51,7 +51,7 @@ where
 }
 
 // @has 'foo/struct.Struct2.html'
-// @snapshot struct2 - '//*[@class="docblock item-decl"]'
+// @snapshot struct2 - '//*[@class="item-decl"]'
 // There should be a whitespace before `{` in this case!
 pub struct Struct2<'a, B: ?Sized + ToOwned<Clone> + 'a> {
     pub a: &'a B,
@@ -59,7 +59,7 @@ pub struct Struct2<'a, B: ?Sized + ToOwned<Clone> + 'a> {
 }
 
 // @has 'foo/union.Union.html'
-// @snapshot union - '//*[@class="docblock item-decl"]'
+// @snapshot union - '//*[@class="item-decl"]'
 pub union Union<'a, B: ?Sized + 'a>
 where
     B: ToOwned<Clone>,
@@ -69,7 +69,7 @@ where
 }
 
 // @has 'foo/union.Union2.html'
-// @snapshot union2 - '//*[@class="docblock item-decl"]'
+// @snapshot union2 - '//*[@class="item-decl"]'
 // There should be a whitespace before `{` in this case!
 pub union Union2<'a, B: ?Sized + ToOwned<Clone> + 'a> {
     a: &'a B,
diff --git a/src/test/rustdoc/whitespace-after-where-clause.struct.html b/src/test/rustdoc/whitespace-after-where-clause.struct.html
index 236cc3b30d08..1ba1367d20f7 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.struct.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.struct.html
@@ -1,4 +1,4 @@
-<div class="docblock item-decl"><pre class="rust struct"><code>pub struct Struct&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a&gt; <span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt;,&#160;</span>{
+<div class="item-decl"><pre class="rust struct"><code>pub struct Struct&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt;,</span>{
     pub a: <a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B,
     pub b: <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>,
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.struct2.html b/src/test/rustdoc/whitespace-after-where-clause.struct2.html
index 47f5c6ba9c84..fb06b0f77c5c 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.struct2.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.struct2.html
@@ -1,4 +1,4 @@
-<div class="docblock item-decl"><pre class="rust struct"><code>pub struct Struct2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
+<div class="item-decl"><pre class="rust struct"><code>pub struct Struct2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
     pub a: <a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B,
     pub b: <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>,
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.trait.html b/src/test/rustdoc/whitespace-after-where-clause.trait.html
index 98f03b837b52..16b558237035 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.trait.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.trait.html
@@ -1,6 +1,6 @@
-<div class="docblock item-decl"><pre class="rust trait"><code>pub trait ToOwned&lt;T&gt; <span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,&#160;</span>{
+<div class="item-decl"><pre class="rust trait"><code>pub trait ToOwned&lt;T&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,</span>{
     type <a href="#associatedtype.Owned" class="associatedtype">Owned</a>;
 
     fn <a href="#tymethod.to_owned" class="fnname">to_owned</a>(&amp;self) -&gt; Self::<a class="associatedtype" href="trait.ToOwned.html#associatedtype.Owned" title="type foo::ToOwned::Owned">Owned</a>;
 <span class="item-spacer" />    fn <a href="#tymethod.whatever" class="fnname">whatever</a>(&amp;self) -&gt; T;
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.trait2.html b/src/test/rustdoc/whitespace-after-where-clause.trait2.html
index 35052869e762..eeca6e1f5008 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.trait2.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.trait2.html
@@ -1,6 +1,6 @@
-<div class="docblock item-decl"><pre class="rust trait"><code>pub trait ToOwned2&lt;T:&#160;<a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; {
+<div class="item-decl"><pre class="rust trait"><code>pub trait ToOwned2&lt;T:&#160;<a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; {
     type <a href="#associatedtype.Owned" class="associatedtype">Owned</a>;
 
     fn <a href="#tymethod.to_owned" class="fnname">to_owned</a>(&amp;self) -&gt; Self::<a class="associatedtype" href="trait.ToOwned2.html#associatedtype.Owned" title="type foo::ToOwned2::Owned">Owned</a>;
 <span class="item-spacer" />    fn <a href="#tymethod.whatever" class="fnname">whatever</a>(&amp;self) -&gt; T;
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.union.html b/src/test/rustdoc/whitespace-after-where-clause.union.html
index 97e1bbcf339f..0dfb6407d45f 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.union.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.union.html
@@ -1,3 +1,3 @@
-<div class="docblock item-decl"><pre class="rust union"><code>pub union Union&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a&gt; <span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt;,&#160;</span>{
+<div class="item-decl"><pre class="rust union"><code>pub union Union&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt;,</span>{
     /* private fields */
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/rustdoc/whitespace-after-where-clause.union2.html b/src/test/rustdoc/whitespace-after-where-clause.union2.html
index 6c752a8b4c5e..0d237df53c7f 100644
--- a/src/test/rustdoc/whitespace-after-where-clause.union2.html
+++ b/src/test/rustdoc/whitespace-after-where-clause.union2.html
@@ -1,3 +1,3 @@
-<div class="docblock item-decl"><pre class="rust union"><code>pub union Union2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
+<div class="item-decl"><pre class="rust union"><code>pub union Union2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
     /* private fields */
-}</code></pre></div>
+}</code></pre></div>
\ No newline at end of file
diff --git a/src/test/ui-fulldeps/auxiliary/issue-40001-plugin.rs b/src/test/ui-fulldeps/auxiliary/issue-40001-plugin.rs
index 802b867a301a..03da804bd1c1 100644
--- a/src/test/ui-fulldeps/auxiliary/issue-40001-plugin.rs
+++ b/src/test/ui-fulldeps/auxiliary/issue-40001-plugin.rs
@@ -21,7 +21,7 @@ use rustc_span::source_map;
 #[no_mangle]
 fn __rustc_plugin_registrar(reg: &mut Registry) {
     reg.lint_store.register_lints(&[&MISSING_ALLOWED_ATTR]);
-    reg.lint_store.register_late_pass(|| Box::new(MissingAllowedAttrPass));
+    reg.lint_store.register_late_pass(|_| Box::new(MissingAllowedAttrPass));
 }
 
 declare_lint! {
@@ -44,7 +44,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingAllowedAttrPass {
     ) {
         let item = match cx.tcx.hir().get(id) {
             Node::Item(item) => item,
-            _ => cx.tcx.hir().expect_item(cx.tcx.hir().get_parent_item(id)),
+            _ => cx.tcx.hir().expect_item(cx.tcx.hir().get_parent_item(id).def_id),
         };
 
         let allowed = |attr| pprust::attribute_to_string(attr).contains("allowed_attr");
diff --git a/src/test/ui-fulldeps/auxiliary/lint-for-crate-rpass.rs b/src/test/ui-fulldeps/auxiliary/lint-for-crate-rpass.rs
index bc153faa8925..a3b570ad8c40 100644
--- a/src/test/ui-fulldeps/auxiliary/lint-for-crate-rpass.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint-for-crate-rpass.rs
@@ -74,7 +74,7 @@ fn __rustc_plugin_registrar(reg: &mut Registry) {
         &CRATE_NOT_GREY,
         &CRATE_NOT_GREEN,
     ]);
-    reg.lint_store.register_late_pass(|| Box::new(PassOkay));
-    reg.lint_store.register_late_pass(|| Box::new(PassRedBlue));
-    reg.lint_store.register_late_pass(|| Box::new(PassGreyGreen));
+    reg.lint_store.register_late_pass(|_| Box::new(PassOkay));
+    reg.lint_store.register_late_pass(|_| Box::new(PassRedBlue));
+    reg.lint_store.register_late_pass(|_| Box::new(PassGreyGreen));
 }
diff --git a/src/test/ui-fulldeps/auxiliary/lint-for-crate.rs b/src/test/ui-fulldeps/auxiliary/lint-for-crate.rs
index 29d0abfbe538..0b1534939b77 100644
--- a/src/test/ui-fulldeps/auxiliary/lint-for-crate.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint-for-crate.rs
@@ -39,5 +39,5 @@ impl<'tcx> LateLintPass<'tcx> for Pass {
 #[no_mangle]
 fn __rustc_plugin_registrar(reg: &mut Registry) {
     reg.lint_store.register_lints(&[&CRATE_NOT_OKAY]);
-    reg.lint_store.register_late_pass(|| Box::new(Pass));
+    reg.lint_store.register_late_pass(|_| Box::new(Pass));
 }
diff --git a/src/test/ui-fulldeps/auxiliary/lint-group-plugin-test.rs b/src/test/ui-fulldeps/auxiliary/lint-group-plugin-test.rs
index 691cfb97d921..2d41b5f30e97 100644
--- a/src/test/ui-fulldeps/auxiliary/lint-group-plugin-test.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint-group-plugin-test.rs
@@ -36,7 +36,7 @@ impl<'tcx> LateLintPass<'tcx> for Pass {
 #[no_mangle]
 fn __rustc_plugin_registrar(reg: &mut Registry) {
     reg.lint_store.register_lints(&[&TEST_LINT, &PLEASE_LINT]);
-    reg.lint_store.register_late_pass(|| Box::new(Pass));
+    reg.lint_store.register_late_pass(|_| Box::new(Pass));
     reg.lint_store.register_group(
         true,
         "lint_me",
diff --git a/src/test/ui-fulldeps/internal-lints/diagnostics.rs b/src/test/ui-fulldeps/internal-lints/diagnostics.rs
index 33192433bbf3..18e39108ecab 100644
--- a/src/test/ui-fulldeps/internal-lints/diagnostics.rs
+++ b/src/test/ui-fulldeps/internal-lints/diagnostics.rs
@@ -1,6 +1,7 @@
 // compile-flags: -Z unstable-options
 
 #![crate_type = "lib"]
+#![feature(rustc_attrs)]
 #![feature(rustc_private)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
@@ -10,64 +11,73 @@ extern crate rustc_macros;
 extern crate rustc_session;
 extern crate rustc_span;
 
-use rustc_errors::{AddSubdiagnostic, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, fluent};
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
-use rustc_session::{parse::ParseSess, SessionDiagnostic};
+use rustc_errors::{
+    AddToDiagnostic, IntoDiagnostic, Diagnostic, DiagnosticBuilder,
+    ErrorGuaranteed, Handler, fluent
+};
+use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::Span;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(parser::expect_path)]
-struct DeriveSessionDiagnostic {
+struct DeriveDiagnostic {
     #[primary_span]
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[note(parser::add_paren)]
 struct Note {
     #[primary_span]
     span: Span,
 }
 
-pub struct UntranslatableInSessionDiagnostic;
+pub struct UntranslatableInIntoDiagnostic;
 
-impl<'a> SessionDiagnostic<'a, ErrorGuaranteed> for UntranslatableInSessionDiagnostic {
-    fn into_diagnostic(self, sess: &'a ParseSess) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        sess.struct_err("untranslatable diagnostic")
+impl<'a> IntoDiagnostic<'a, ErrorGuaranteed> for UntranslatableInIntoDiagnostic {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+        handler.struct_err("untranslatable diagnostic")
         //~^ ERROR diagnostics should be created using translatable messages
     }
 }
 
-pub struct TranslatableInSessionDiagnostic;
+pub struct TranslatableInIntoDiagnostic;
 
-impl<'a> SessionDiagnostic<'a, ErrorGuaranteed> for TranslatableInSessionDiagnostic {
-    fn into_diagnostic(self, sess: &'a ParseSess) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        sess.struct_err(fluent::parser::expect_path)
+impl<'a> IntoDiagnostic<'a, ErrorGuaranteed> for TranslatableInIntoDiagnostic {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+        handler.struct_err(fluent::parser::expect_path)
     }
 }
 
-pub struct UntranslatableInAddSubdiagnostic;
+pub struct UntranslatableInAddToDiagnostic;
 
-impl AddSubdiagnostic for UntranslatableInAddSubdiagnostic {
+impl AddToDiagnostic for UntranslatableInAddToDiagnostic {
     fn add_to_diagnostic(self, diag: &mut Diagnostic) {
         diag.note("untranslatable diagnostic");
         //~^ ERROR diagnostics should be created using translatable messages
     }
 }
 
-pub struct TranslatableInAddSubdiagnostic;
+pub struct TranslatableInAddToDiagnostic;
 
-impl AddSubdiagnostic for TranslatableInAddSubdiagnostic {
+impl AddToDiagnostic for TranslatableInAddToDiagnostic {
     fn add_to_diagnostic(self, diag: &mut Diagnostic) {
         diag.note(fluent::typeck::note);
     }
 }
 
-pub fn make_diagnostics<'a>(sess: &'a ParseSess) {
-    let _diag = sess.struct_err(fluent::parser::expect_path);
-    //~^ ERROR diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls
+pub fn make_diagnostics<'a>(handler: &'a Handler) {
+    let _diag = handler.struct_err(fluent::parser::expect_path);
+    //~^ ERROR diagnostics should only be created in `IntoDiagnostic`/`AddToDiagnostic` impls
 
-    let _diag = sess.struct_err("untranslatable diagnostic");
-    //~^ ERROR diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls
+    let _diag = handler.struct_err("untranslatable diagnostic");
+    //~^ ERROR diagnostics should only be created in `IntoDiagnostic`/`AddToDiagnostic` impls
     //~^^ ERROR diagnostics should be created using translatable messages
 }
+
+// Check that `rustc_lint_diagnostics`-annotated functions aren't themselves linted.
+
+#[rustc_lint_diagnostics]
+pub fn skipped_because_of_annotation<'a>(handler: &'a Handler) {
+    let _diag = handler.struct_err("untranslatable diagnostic"); // okay!
+}
diff --git a/src/test/ui-fulldeps/internal-lints/diagnostics.stderr b/src/test/ui-fulldeps/internal-lints/diagnostics.stderr
index bae78ffdc021..9219d09e9b40 100644
--- a/src/test/ui-fulldeps/internal-lints/diagnostics.stderr
+++ b/src/test/ui-fulldeps/internal-lints/diagnostics.stderr
@@ -1,44 +1,44 @@
 error: diagnostics should be created using translatable messages
-  --> $DIR/diagnostics.rs:36:14
+  --> $DIR/diagnostics.rs:39:17
    |
-LL |         sess.struct_err("untranslatable diagnostic")
-   |              ^^^^^^^^^^
+LL |         handler.struct_err("untranslatable diagnostic")
+   |                 ^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/diagnostics.rs:5:9
+  --> $DIR/diagnostics.rs:6:9
    |
 LL | #![deny(rustc::untranslatable_diagnostic)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: diagnostics should be created using translatable messages
-  --> $DIR/diagnostics.rs:53:14
+  --> $DIR/diagnostics.rs:56:14
    |
 LL |         diag.note("untranslatable diagnostic");
    |              ^^^^
 
-error: diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls
-  --> $DIR/diagnostics.rs:67:22
+error: diagnostics should only be created in `IntoDiagnostic`/`AddToDiagnostic` impls
+  --> $DIR/diagnostics.rs:70:25
    |
-LL |     let _diag = sess.struct_err(fluent::parser::expect_path);
-   |                      ^^^^^^^^^^
+LL |     let _diag = handler.struct_err(fluent::parser::expect_path);
+   |                         ^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/diagnostics.rs:6:9
+  --> $DIR/diagnostics.rs:7:9
    |
 LL | #![deny(rustc::diagnostic_outside_of_impl)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls
-  --> $DIR/diagnostics.rs:70:22
+error: diagnostics should only be created in `IntoDiagnostic`/`AddToDiagnostic` impls
+  --> $DIR/diagnostics.rs:73:25
    |
-LL |     let _diag = sess.struct_err("untranslatable diagnostic");
-   |                      ^^^^^^^^^^
+LL |     let _diag = handler.struct_err("untranslatable diagnostic");
+   |                         ^^^^^^^^^^
 
 error: diagnostics should be created using translatable messages
-  --> $DIR/diagnostics.rs:70:22
+  --> $DIR/diagnostics.rs:73:25
    |
-LL |     let _diag = sess.struct_err("untranslatable diagnostic");
-   |                      ^^^^^^^^^^
+LL |     let _diag = handler.struct_err("untranslatable diagnostic");
+   |                         ^^^^^^^^^^
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
index b1f557cb94de..ad481c14bab8 100644
--- a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
+++ b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
@@ -1,10 +1,10 @@
 // check-fail
-// Tests error conditions for specifying diagnostics using #[derive(SessionDiagnostic)]
+// Tests error conditions for specifying diagnostics using #[derive(Diagnostic)]
 
 // normalize-stderr-test "the following other types implement trait `IntoDiagnosticArg`:(?:.*\n){0,9}\s+and \d+ others" -> "normalized in stderr"
-
+// normalize-stderr-test "diagnostic_builder\.rs:[0-9]+:[0-9]+" -> "diagnostic_builder.rs:LL:CC"
 // The proc_macro2 crate handles spans differently when on beta/stable release rather than nightly,
-// changing the output of this test. Since SessionDiagnostic is strictly internal to the compiler
+// changing the output of this test. Since Diagnostic is strictly internal to the compiler
 // the test is just ignored on stable and beta:
 // ignore-beta
 // ignore-stable
@@ -17,7 +17,7 @@ use rustc_span::symbol::Ident;
 use rustc_span::Span;
 
 extern crate rustc_macros;
-use rustc_macros::{SessionDiagnostic, LintDiagnostic, SessionSubdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 
 extern crate rustc_middle;
 use rustc_middle::ty::Ty;
@@ -27,70 +27,72 @@ use rustc_errors::{Applicability, MultiSpan};
 
 extern crate rustc_session;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct Hello {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct HelloWarn {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
-//~^ ERROR `#[derive(SessionDiagnostic)]` can only be used on structs
-enum SessionDiagnosticOnEnum {
+//~^ ERROR `#[derive(Diagnostic)]` can only be used on structs
+enum DiagnosticOnEnum {
     Foo,
     Bar,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[diag = "E0123"]
 //~^ ERROR `#[diag = ...]` is not a valid attribute
 struct WrongStructAttrStyle {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[nonsense(typeck::ambiguous_lifetime_bound, code = "E0123")]
 //~^ ERROR `#[nonsense(...)]` is not a valid attribute
 //~^^ ERROR diagnostic slug not specified
 //~^^^ ERROR cannot find attribute `nonsense` in this scope
 struct InvalidStructAttr {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag("E0123")]
 //~^ ERROR `#[diag("...")]` is not a valid attribute
 //~^^ ERROR diagnostic slug not specified
 struct InvalidLitNestedAttr {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(nonsense, code = "E0123")]
 //~^ ERROR cannot find value `nonsense` in module `rustc_errors::fluent`
 struct InvalidNestedStructAttr {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(nonsense("foo"), code = "E0123", slug = "foo")]
 //~^ ERROR `#[diag(nonsense(...))]` is not a valid attribute
 //~^^ ERROR diagnostic slug not specified
 struct InvalidNestedStructAttr1 {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(nonsense = "...", code = "E0123", slug = "foo")]
 //~^ ERROR `#[diag(nonsense = ...)]` is not a valid attribute
-//~^^ ERROR diagnostic slug not specified
+//~| ERROR `#[diag(slug = ...)]` is not a valid attribute
+//~| ERROR diagnostic slug not specified
 struct InvalidNestedStructAttr2 {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(nonsense = 4, code = "E0123", slug = "foo")]
 //~^ ERROR `#[diag(nonsense = ...)]` is not a valid attribute
-//~^^ ERROR diagnostic slug not specified
+//~| ERROR `#[diag(slug = ...)]` is not a valid attribute
+//~| ERROR diagnostic slug not specified
 struct InvalidNestedStructAttr3 {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123", slug = "foo")]
 //~^ ERROR `#[diag(slug = ...)]` is not a valid attribute
 struct InvalidNestedStructAttr4 {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct WrongPlaceField {
     #[suggestion = "bar"]
@@ -98,36 +100,36 @@ struct WrongPlaceField {
     sp: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0456")]
 //~^ ERROR specified multiple times
 //~^^ ERROR specified multiple times
 struct DiagSpecifiedTwice {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0456", code = "E0457")]
 //~^ ERROR specified multiple times
 struct CodeSpecifiedTwice {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, typeck::ambiguous_lifetime_bound, code = "E0456")]
 //~^ ERROR `#[diag(typeck::ambiguous_lifetime_bound)]` is not a valid attribute
 struct SlugSpecifiedTwice {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 struct KindNotProvided {} //~ ERROR diagnostic slug not specified
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(code = "E0456")]
 //~^ ERROR diagnostic slug not specified
 struct SlugNotProvided {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound)]
 struct CodeNotProvided {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct MessageWrongType {
     #[primary_span]
@@ -135,7 +137,7 @@ struct MessageWrongType {
     foo: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct InvalidPathFieldAttr {
     #[nonsense]
@@ -144,7 +146,7 @@ struct InvalidPathFieldAttr {
     foo: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithField {
     name: String,
@@ -152,7 +154,7 @@ struct ErrorWithField {
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithMessageAppliedToField {
     #[label(typeck::label)]
@@ -160,7 +162,7 @@ struct ErrorWithMessageAppliedToField {
     name: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithNonexistentField {
     #[suggestion(typeck::suggestion, code = "{name}")]
@@ -168,7 +170,7 @@ struct ErrorWithNonexistentField {
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 //~^ ERROR invalid format string: expected `'}'`
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorMissingClosingBrace {
@@ -178,7 +180,7 @@ struct ErrorMissingClosingBrace {
     val: usize,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 //~^ ERROR invalid format string: unmatched `}`
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorMissingOpeningBrace {
@@ -188,14 +190,14 @@ struct ErrorMissingOpeningBrace {
     val: usize,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct LabelOnSpan {
     #[label(typeck::label)]
     sp: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct LabelOnNonSpan {
     #[label(typeck::label)]
@@ -203,7 +205,7 @@ struct LabelOnNonSpan {
     id: u32,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct Suggest {
     #[suggestion(typeck::suggestion, code = "This is the suggested code")]
@@ -213,44 +215,47 @@ struct Suggest {
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithoutCode {
     #[suggestion(typeck::suggestion)]
+    //~^ ERROR suggestion without `code = "..."`
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithBadKey {
     #[suggestion(nonsense = "bar")]
     //~^ ERROR `#[suggestion(nonsense = ...)]` is not a valid attribute
+    //~| ERROR suggestion without `code = "..."`
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithShorthandMsg {
     #[suggestion(msg = "bar")]
     //~^ ERROR `#[suggestion(msg = ...)]` is not a valid attribute
+    //~| ERROR suggestion without `code = "..."`
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithoutMsg {
     #[suggestion(code = "bar")]
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithTypesSwapped {
     #[suggestion(typeck::suggestion, code = "This is suggested code")]
     suggestion: (Applicability, Span),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithWrongTypeApplicabilityOnly {
     #[suggestion(typeck::suggestion, code = "This is suggested code")]
@@ -258,30 +263,30 @@ struct SuggestWithWrongTypeApplicabilityOnly {
     suggestion: Applicability,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithSpanOnly {
     #[suggestion(typeck::suggestion, code = "This is suggested code")]
     suggestion: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithDuplicateSpanAndApplicability {
     #[suggestion(typeck::suggestion, code = "This is suggested code")]
-    //~^ ERROR type of field annotated with `#[suggestion(...)]` contains more than one `Span`
     suggestion: (Span, Span, Applicability),
+    //~^ ERROR specified multiple times
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct SuggestWithDuplicateApplicabilityAndSpan {
     #[suggestion(typeck::suggestion, code = "This is suggested code")]
-    //~^ ERROR type of field annotated with `#[suggestion(...)]` contains more than one
     suggestion: (Applicability, Applicability, Span),
+    //~^ ERROR specified multiple times
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct WrongKindOfAnnotation {
     #[label = "bar"]
@@ -289,16 +294,16 @@ struct WrongKindOfAnnotation {
     z: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct OptionsInErrors {
     #[label(typeck::label)]
     label: Option<Span>,
-    #[suggestion(typeck::suggestion)]
+    #[suggestion(typeck::suggestion, code = "...")]
     opt_sugg: Option<(Span, Applicability)>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0456")]
 struct MoveOutOfBorrowError<'tcx> {
     name: Ident,
@@ -312,7 +317,7 @@ struct MoveOutOfBorrowError<'tcx> {
     opt_sugg: Option<(Span, Applicability)>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithLifetime<'a> {
     #[label(typeck::label)]
@@ -320,7 +325,7 @@ struct ErrorWithLifetime<'a> {
     name: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithDefaultLabelAttr<'a> {
     #[label]
@@ -328,7 +333,7 @@ struct ErrorWithDefaultLabelAttr<'a> {
     name: &'a str,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 //~^ ERROR the trait bound `Hello: IntoDiagnosticArg` is not satisfied
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ArgFieldWithoutSkip {
@@ -337,7 +342,7 @@ struct ArgFieldWithoutSkip {
     other: Hello,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ArgFieldWithSkip {
     #[primary_span]
@@ -348,99 +353,99 @@ struct ArgFieldWithSkip {
     other: Hello,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithSpannedNote {
     #[note]
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithSpannedNoteCustom {
     #[note(typeck::note)]
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[note]
 struct ErrorWithNote {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[note(typeck::note)]
 struct ErrorWithNoteCustom {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithSpannedHelp {
     #[help]
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithSpannedHelpCustom {
     #[help(typeck::help)]
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[help]
 struct ErrorWithHelp {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[help(typeck::help)]
 struct ErrorWithHelpCustom {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[help]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithHelpWrongOrder {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[help(typeck::help)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithHelpCustomWrongOrder {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[note]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithNoteWrongOrder {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[note(typeck::note)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithNoteCustomWrongOrder {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ApplicabilityInBoth {
     #[suggestion(typeck::suggestion, code = "...", applicability = "maybe-incorrect")]
-    //~^ ERROR applicability cannot be set in both the field and attribute
+    //~^ ERROR specified multiple times
     suggestion: (Span, Applicability),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct InvalidApplicability {
     #[suggestion(typeck::suggestion, code = "...", applicability = "batman")]
@@ -448,32 +453,32 @@ struct InvalidApplicability {
     suggestion: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ValidApplicability {
     #[suggestion(typeck::suggestion, code = "...", applicability = "maybe-incorrect")]
     suggestion: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct NoApplicability {
     #[suggestion(typeck::suggestion, code = "...")]
     suggestion: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[note(parser::add_paren)]
 struct Note;
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound)]
 struct Subdiagnostic {
     #[subdiagnostic]
     note: Note,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct VecField {
     #[primary_span]
@@ -481,7 +486,7 @@ struct VecField {
     spans: Vec<Span>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct UnitField {
     #[primary_span]
@@ -492,7 +497,7 @@ struct UnitField {
     bar: (),
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct OptUnitField {
     #[primary_span]
@@ -503,27 +508,27 @@ struct OptUnitField {
     bar: Option<()>,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct LabelWithTrailingPath {
     #[label(typeck::label, foo)]
-    //~^ ERROR `#[label(...)]` is not a valid attribute
+    //~^ ERROR `#[label(foo)]` is not a valid attribute
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct LabelWithTrailingNameValue {
     #[label(typeck::label, foo = "...")]
-    //~^ ERROR `#[label(...)]` is not a valid attribute
+    //~^ ERROR `#[label(foo = ...)]` is not a valid attribute
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct LabelWithTrailingList {
     #[label(typeck::label, foo("..."))]
-    //~^ ERROR `#[label(...)]` is not a valid attribute
+    //~^ ERROR `#[label(foo(...))]` is not a valid attribute
     span: Span,
 }
 
@@ -540,35 +545,35 @@ struct PrimarySpanOnLint {
     span: Span,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 struct ErrorWithMultiSpan {
     #[primary_span]
     span: MultiSpan,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 #[warning]
 struct ErrorWithWarn {
     val: String,
 }
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[error(typeck::ambiguous_lifetime_bound, code = "E0123")]
 //~^ ERROR `#[error(...)]` is not a valid attribute
 //~| ERROR diagnostic slug not specified
 //~| ERROR cannot find attribute `error` in this scope
 struct ErrorAttribute {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[warn_(typeck::ambiguous_lifetime_bound, code = "E0123")]
 //~^ ERROR `#[warn_(...)]` is not a valid attribute
 //~| ERROR diagnostic slug not specified
 //~| ERROR cannot find attribute `warn_` in this scope
 struct WarnAttribute {}
 
-#[derive(SessionDiagnostic)]
+#[derive(Diagnostic)]
 #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
 //~^ ERROR `#[lint(...)]` is not a valid attribute
 //~| ERROR diagnostic slug not specified
@@ -581,3 +586,68 @@ struct LintAttributeOnSessionDiag {}
 //~| ERROR diagnostic slug not specified
 //~| ERROR cannot find attribute `lint` in this scope
 struct LintAttributeOnLintDiag {}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+struct DuplicatedSuggestionCode {
+    #[suggestion(typeck::suggestion, code = "...", code = ",,,")]
+    //~^ ERROR specified multiple times
+    suggestion: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+struct InvalidTypeInSuggestionTuple {
+    #[suggestion(typeck::suggestion, code = "...")]
+    suggestion: (Span, usize),
+    //~^ ERROR wrong types for suggestion
+}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+struct MissingApplicabilityInSuggestionTuple {
+    #[suggestion(typeck::suggestion, code = "...")]
+    suggestion: (Span,),
+    //~^ ERROR wrong types for suggestion
+}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+struct MissingCodeInSuggestion {
+    #[suggestion(typeck::suggestion)]
+    //~^ ERROR suggestion without `code = "..."`
+    suggestion: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+#[multipart_suggestion(typeck::suggestion)]
+//~^ ERROR `#[multipart_suggestion(...)]` is not a valid attribute
+//~| ERROR cannot find attribute `multipart_suggestion` in this scope
+#[multipart_suggestion()]
+//~^ ERROR `#[multipart_suggestion(...)]` is not a valid attribute
+//~| ERROR cannot find attribute `multipart_suggestion` in this scope
+struct MultipartSuggestion {
+    #[multipart_suggestion(typeck::suggestion)]
+    //~^ ERROR `#[multipart_suggestion(...)]` is not a valid attribute
+    //~| ERROR cannot find attribute `multipart_suggestion` in this scope
+    suggestion: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+#[suggestion(typeck::suggestion, code = "...")]
+//~^ ERROR `#[suggestion(...)]` is not a valid attribute
+struct SuggestionOnStruct {
+    #[primary_span]
+    suggestion: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
+#[label]
+//~^ ERROR `#[label]` is not a valid attribute
+struct LabelOnStruct {
+    #[primary_span]
+    suggestion: Span,
+}
diff --git a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
index 621c59f44895..9919b12beaf0 100644
--- a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
+++ b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
@@ -1,9 +1,9 @@
-error: `#[derive(SessionDiagnostic)]` can only be used on structs
+error: `#[derive(Diagnostic)]` can only be used on structs
   --> $DIR/diagnostic-derive.rs:39:1
    |
 LL | / #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
 LL | |
-LL | | enum SessionDiagnosticOnEnum {
+LL | | enum DiagnosticOnEnum {
 LL | |     Foo,
 LL | |     Bar,
 LL | | }
@@ -20,8 +20,6 @@ error: `#[nonsense(...)]` is not a valid attribute
    |
 LL | #[nonsense(typeck::ambiguous_lifetime_bound, code = "E0123")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: only `diag`, `help`, `note` and `warning` are valid attributes
 
 error: diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:53:1
@@ -41,7 +39,7 @@ error: `#[diag("...")]` is not a valid attribute
 LL | #[diag("E0123")]
    |        ^^^^^^^
    |
-   = help: first argument of the attribute should be the diagnostic slug
+   = help: a diagnostic slug is required as the first argument
 
 error: diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:60:1
@@ -60,7 +58,7 @@ error: `#[diag(nonsense(...))]` is not a valid attribute
 LL | #[diag(nonsense("foo"), code = "E0123", slug = "foo")]
    |        ^^^^^^^^^^^^^^^
    |
-   = help: first argument of the attribute should be the diagnostic slug
+   = help: a diagnostic slug is required as the first argument
 
 error: diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:71:1
@@ -79,7 +77,15 @@ error: `#[diag(nonsense = ...)]` is not a valid attribute
 LL | #[diag(nonsense = "...", code = "E0123", slug = "foo")]
    |        ^^^^^^^^^^^^^^^^
    |
-   = help: first argument of the attribute should be the diagnostic slug
+   = help: only `code` is a valid nested attributes following the slug
+
+error: `#[diag(slug = ...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:77:42
+   |
+LL | #[diag(nonsense = "...", code = "E0123", slug = "foo")]
+   |                                          ^^^^^^^^^^^^
+   |
+   = help: only `code` is a valid nested attributes following the slug
 
 error: diagnostic slug not specified
   --> $DIR/diagnostic-derive.rs:77:1
@@ -87,32 +93,40 @@ error: diagnostic slug not specified
 LL | / #[diag(nonsense = "...", code = "E0123", slug = "foo")]
 LL | |
 LL | |
+LL | |
 LL | | struct InvalidNestedStructAttr2 {}
    | |__________________________________^
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: `#[diag(nonsense = ...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:83:8
+  --> $DIR/diagnostic-derive.rs:84:8
    |
 LL | #[diag(nonsense = 4, code = "E0123", slug = "foo")]
    |        ^^^^^^^^^^^^
+
+error: `#[diag(slug = ...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:84:38
    |
-   = help: first argument of the attribute should be the diagnostic slug
+LL | #[diag(nonsense = 4, code = "E0123", slug = "foo")]
+   |                                      ^^^^^^^^^^^^
+   |
+   = help: only `code` is a valid nested attributes following the slug
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:83:1
+  --> $DIR/diagnostic-derive.rs:84:1
    |
 LL | / #[diag(nonsense = 4, code = "E0123", slug = "foo")]
 LL | |
 LL | |
+LL | |
 LL | | struct InvalidNestedStructAttr3 {}
    | |__________________________________^
    |
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: `#[diag(slug = ...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:89:58
+  --> $DIR/diagnostic-derive.rs:91:58
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0123", slug = "foo")]
    |                                                          ^^^^^^^^^^^^
@@ -120,55 +134,57 @@ LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0123", slug = "foo")]
    = help: only `code` is a valid nested attributes following the slug
 
 error: `#[suggestion = ...]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:96:5
+  --> $DIR/diagnostic-derive.rs:98:5
    |
 LL |     #[suggestion = "bar"]
    |     ^^^^^^^^^^^^^^^^^^^^^
 
 error: specified multiple times
-  --> $DIR/diagnostic-derive.rs:103:1
+  --> $DIR/diagnostic-derive.rs:105:8
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0456")]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/diagnostic-derive.rs:102:1
+  --> $DIR/diagnostic-derive.rs:104:8
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: specified multiple times
-  --> $DIR/diagnostic-derive.rs:103:49
+  --> $DIR/diagnostic-derive.rs:105:49
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0456")]
    |                                                 ^^^^^^^
    |
 note: previously specified here
-  --> $DIR/diagnostic-derive.rs:102:49
+  --> $DIR/diagnostic-derive.rs:104:49
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0123")]
    |                                                 ^^^^^^^
 
 error: specified multiple times
-  --> $DIR/diagnostic-derive.rs:109:65
+  --> $DIR/diagnostic-derive.rs:111:65
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0456", code = "E0457")]
    |                                                                 ^^^^^^^
    |
 note: previously specified here
-  --> $DIR/diagnostic-derive.rs:109:49
+  --> $DIR/diagnostic-derive.rs:111:49
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, code = "E0456", code = "E0457")]
    |                                                 ^^^^^^^
 
 error: `#[diag(typeck::ambiguous_lifetime_bound)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:114:42
+  --> $DIR/diagnostic-derive.rs:116:42
    |
 LL | #[diag(typeck::ambiguous_lifetime_bound, typeck::ambiguous_lifetime_bound, code = "E0456")]
    |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: diagnostic slug must be the first argument
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:119:1
+  --> $DIR/diagnostic-derive.rs:121:1
    |
 LL | struct KindNotProvided {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -176,7 +192,7 @@ LL | struct KindNotProvided {}
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:122:1
+  --> $DIR/diagnostic-derive.rs:124:1
    |
 LL | / #[diag(code = "E0456")]
 LL | |
@@ -186,75 +202,91 @@ LL | | struct SlugNotProvided {}
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/diagnostic-derive.rs:133:5
+  --> $DIR/diagnostic-derive.rs:135:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
 
 error: `#[nonsense]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:141:5
+  --> $DIR/diagnostic-derive.rs:143:5
    |
 LL |     #[nonsense]
    |     ^^^^^^^^^^^
-   |
-   = help: only `skip_arg`, `primary_span`, `label`, `note`, `help` and `subdiagnostic` are valid field attributes
 
 error: the `#[label(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/diagnostic-derive.rs:158:5
+  --> $DIR/diagnostic-derive.rs:160:5
    |
 LL |     #[label(typeck::label)]
    |     ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `name` doesn't refer to a field on this type
-  --> $DIR/diagnostic-derive.rs:166:45
+  --> $DIR/diagnostic-derive.rs:168:45
    |
 LL |     #[suggestion(typeck::suggestion, code = "{name}")]
    |                                             ^^^^^^^^
 
 error: invalid format string: expected `'}'` but string was terminated
-  --> $DIR/diagnostic-derive.rs:171:16
+  --> $DIR/diagnostic-derive.rs:173:16
    |
-LL | #[derive(SessionDiagnostic)]
+LL | #[derive(Diagnostic)]
    |           -    ^ expected `'}'` in format string
    |           |
    |           because of this opening brace
    |
    = note: if you intended to print `{`, you can escape it using `{{`
-   = note: this error originates in the derive macro `SessionDiagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the derive macro `Diagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: invalid format string: unmatched `}` found
-  --> $DIR/diagnostic-derive.rs:181:15
+  --> $DIR/diagnostic-derive.rs:183:15
    |
-LL | #[derive(SessionDiagnostic)]
+LL | #[derive(Diagnostic)]
    |               ^ unmatched `}` in format string
    |
    = note: if you intended to print `}`, you can escape it using `}}`
-   = note: this error originates in the derive macro `SessionDiagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the derive macro `Diagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: the `#[label(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/diagnostic-derive.rs:201:5
+  --> $DIR/diagnostic-derive.rs:203:5
    |
 LL |     #[label(typeck::label)]
    |     ^^^^^^^^^^^^^^^^^^^^^^^
 
+error: suggestion without `code = "..."`
+  --> $DIR/diagnostic-derive.rs:221:5
+   |
+LL |     #[suggestion(typeck::suggestion)]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error: `#[suggestion(nonsense = ...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:226:18
+  --> $DIR/diagnostic-derive.rs:229:18
    |
 LL |     #[suggestion(nonsense = "bar")]
    |                  ^^^^^^^^^^^^^^^^
    |
-   = help: only `message`, `code` and `applicability` are valid field attributes
+   = help: only `code` and `applicability` are valid nested attributes
+
+error: suggestion without `code = "..."`
+  --> $DIR/diagnostic-derive.rs:229:5
+   |
+LL |     #[suggestion(nonsense = "bar")]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion(msg = ...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:234:18
+  --> $DIR/diagnostic-derive.rs:238:18
    |
 LL |     #[suggestion(msg = "bar")]
    |                  ^^^^^^^^^^^
    |
-   = help: only `message`, `code` and `applicability` are valid field attributes
+   = help: only `code` and `applicability` are valid nested attributes
+
+error: suggestion without `code = "..."`
+  --> $DIR/diagnostic-derive.rs:238:5
+   |
+LL |     #[suggestion(msg = "bar")]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: wrong field type for suggestion
-  --> $DIR/diagnostic-derive.rs:256:5
+  --> $DIR/diagnostic-derive.rs:261:5
    |
 LL | /     #[suggestion(typeck::suggestion, code = "This is suggested code")]
 LL | |
@@ -263,60 +295,76 @@ LL | |     suggestion: Applicability,
    |
    = help: `#[suggestion(...)]` should be applied to fields of type `Span` or `(Span, Applicability)`
 
-error: type of field annotated with `#[suggestion(...)]` contains more than one `Span`
-  --> $DIR/diagnostic-derive.rs:271:5
+error: specified multiple times
+  --> $DIR/diagnostic-derive.rs:277:24
    |
-LL | /     #[suggestion(typeck::suggestion, code = "This is suggested code")]
-LL | |
-LL | |     suggestion: (Span, Span, Applicability),
-   | |___________________________________________^
+LL |     suggestion: (Span, Span, Applicability),
+   |                        ^^^^
+   |
+note: previously specified here
+  --> $DIR/diagnostic-derive.rs:277:18
+   |
+LL |     suggestion: (Span, Span, Applicability),
+   |                  ^^^^
 
-error: type of field annotated with `#[suggestion(...)]` contains more than one Applicability
-  --> $DIR/diagnostic-derive.rs:279:5
+error: specified multiple times
+  --> $DIR/diagnostic-derive.rs:285:33
    |
-LL | /     #[suggestion(typeck::suggestion, code = "This is suggested code")]
-LL | |
-LL | |     suggestion: (Applicability, Applicability, Span),
-   | |____________________________________________________^
+LL |     suggestion: (Applicability, Applicability, Span),
+   |                                 ^^^^^^^^^^^^^
+   |
+note: previously specified here
+  --> $DIR/diagnostic-derive.rs:285:18
+   |
+LL |     suggestion: (Applicability, Applicability, Span),
+   |                  ^^^^^^^^^^^^^
 
 error: `#[label = ...]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:287:5
+  --> $DIR/diagnostic-derive.rs:292:5
    |
 LL |     #[label = "bar"]
    |     ^^^^^^^^^^^^^^^^
 
-error: applicability cannot be set in both the field and attribute
-  --> $DIR/diagnostic-derive.rs:438:52
+error: specified multiple times
+  --> $DIR/diagnostic-derive.rs:443:52
    |
 LL |     #[suggestion(typeck::suggestion, code = "...", applicability = "maybe-incorrect")]
    |                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: previously specified here
+  --> $DIR/diagnostic-derive.rs:445:24
+   |
+LL |     suggestion: (Span, Applicability),
+   |                        ^^^^^^^^^^^^^
 
 error: invalid applicability
-  --> $DIR/diagnostic-derive.rs:446:52
+  --> $DIR/diagnostic-derive.rs:451:52
    |
 LL |     #[suggestion(typeck::suggestion, code = "...", applicability = "batman")]
    |                                                    ^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: `#[label(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:509:5
+error: `#[label(foo)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:514:28
    |
 LL |     #[label(typeck::label, foo)]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                            ^^^
+   |
+   = help: a diagnostic slug must be the first argument to the attribute
 
-error: `#[label(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:517:5
+error: `#[label(foo = ...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:522:28
    |
 LL |     #[label(typeck::label, foo = "...")]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                            ^^^^^^^^^^^
 
-error: `#[label(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:525:5
+error: `#[label(foo(...))]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:530:28
    |
 LL |     #[label(typeck::label, foo("..."))]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                            ^^^^^^^^^^
 
 error: `#[primary_span]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:538:5
+  --> $DIR/diagnostic-derive.rs:543:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
@@ -324,15 +372,13 @@ LL |     #[primary_span]
    = help: the `primary_span` field attribute is not valid for lint diagnostics
 
 error: `#[error(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:558:1
+  --> $DIR/diagnostic-derive.rs:563:1
    |
 LL | #[error(typeck::ambiguous_lifetime_bound, code = "E0123")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: `error` and `lint` have been replaced by `diag`
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:558:1
+  --> $DIR/diagnostic-derive.rs:563:1
    |
 LL | / #[error(typeck::ambiguous_lifetime_bound, code = "E0123")]
 LL | |
@@ -344,15 +390,13 @@ LL | | struct ErrorAttribute {}
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: `#[warn_(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:565:1
+  --> $DIR/diagnostic-derive.rs:570:1
    |
 LL | #[warn_(typeck::ambiguous_lifetime_bound, code = "E0123")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: `warn_` have been replaced by `warning`
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:565:1
+  --> $DIR/diagnostic-derive.rs:570:1
    |
 LL | / #[warn_(typeck::ambiguous_lifetime_bound, code = "E0123")]
 LL | |
@@ -364,15 +408,13 @@ LL | | struct WarnAttribute {}
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: `#[lint(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:572:1
+  --> $DIR/diagnostic-derive.rs:577:1
    |
 LL | #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: `error` and `lint` have been replaced by `diag`
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:572:1
+  --> $DIR/diagnostic-derive.rs:577:1
    |
 LL | / #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
 LL | |
@@ -384,15 +426,13 @@ LL | | struct LintAttributeOnSessionDiag {}
    = help: specify the slug as the first argument to the `#[diag(...)]` attribute, such as `#[diag(typeck::example_error)]`
 
 error: `#[lint(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:579:1
+  --> $DIR/diagnostic-derive.rs:584:1
    |
 LL | #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: `error` and `lint` have been replaced by `diag`
 
 error: diagnostic slug not specified
-  --> $DIR/diagnostic-derive.rs:579:1
+  --> $DIR/diagnostic-derive.rs:584:1
    |
 LL | / #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
 LL | |
@@ -403,6 +443,80 @@ LL | | struct LintAttributeOnLintDiag {}
    |
    = help: specify the slug as the first argument to the attribute, such as `#[diag(typeck::example_error)]`
 
+error: specified multiple times
+  --> $DIR/diagnostic-derive.rs:593:52
+   |
+LL |     #[suggestion(typeck::suggestion, code = "...", code = ",,,")]
+   |                                                    ^^^^^^^^^^^^
+   |
+note: previously specified here
+  --> $DIR/diagnostic-derive.rs:593:38
+   |
+LL |     #[suggestion(typeck::suggestion, code = "...", code = ",,,")]
+   |                                      ^^^^^^^^^^^^
+
+error: wrong types for suggestion
+  --> $DIR/diagnostic-derive.rs:602:24
+   |
+LL |     suggestion: (Span, usize),
+   |                        ^^^^^
+   |
+   = help: `#[suggestion(...)]` on a tuple field must be applied to fields of type `(Span, Applicability)`
+
+error: wrong types for suggestion
+  --> $DIR/diagnostic-derive.rs:610:17
+   |
+LL |     suggestion: (Span,),
+   |                 ^^^^^^^
+   |
+   = help: `#[suggestion(...)]` on a tuple field must be applied to fields of type `(Span, Applicability)`
+
+error: suggestion without `code = "..."`
+  --> $DIR/diagnostic-derive.rs:617:5
+   |
+LL |     #[suggestion(typeck::suggestion)]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `#[multipart_suggestion(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:624:1
+   |
+LL | #[multipart_suggestion(typeck::suggestion)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider creating a `Subdiagnostic` instead
+
+error: `#[multipart_suggestion(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:627:1
+   |
+LL | #[multipart_suggestion()]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider creating a `Subdiagnostic` instead
+
+error: `#[multipart_suggestion(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:631:5
+   |
+LL |     #[multipart_suggestion(typeck::suggestion)]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider creating a `Subdiagnostic` instead
+
+error: `#[suggestion(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:639:1
+   |
+LL | #[suggestion(typeck::suggestion, code = "...")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: `#[label]` and `#[suggestion]` can only be applied to fields
+
+error: `#[label]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:648:1
+   |
+LL | #[label]
+   | ^^^^^^^^
+   |
+   = help: `#[label]` and `#[suggestion]` can only be applied to fields
+
 error: cannot find attribute `nonsense` in this scope
   --> $DIR/diagnostic-derive.rs:53:3
    |
@@ -410,35 +524,53 @@ LL | #[nonsense(typeck::ambiguous_lifetime_bound, code = "E0123")]
    |   ^^^^^^^^
 
 error: cannot find attribute `nonsense` in this scope
-  --> $DIR/diagnostic-derive.rs:141:7
+  --> $DIR/diagnostic-derive.rs:143:7
    |
 LL |     #[nonsense]
    |       ^^^^^^^^
 
 error: cannot find attribute `error` in this scope
-  --> $DIR/diagnostic-derive.rs:558:3
+  --> $DIR/diagnostic-derive.rs:563:3
    |
 LL | #[error(typeck::ambiguous_lifetime_bound, code = "E0123")]
    |   ^^^^^
 
 error: cannot find attribute `warn_` in this scope
-  --> $DIR/diagnostic-derive.rs:565:3
+  --> $DIR/diagnostic-derive.rs:570:3
    |
 LL | #[warn_(typeck::ambiguous_lifetime_bound, code = "E0123")]
    |   ^^^^^ help: a built-in attribute with a similar name exists: `warn`
 
 error: cannot find attribute `lint` in this scope
-  --> $DIR/diagnostic-derive.rs:572:3
+  --> $DIR/diagnostic-derive.rs:577:3
    |
 LL | #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
    |   ^^^^ help: a built-in attribute with a similar name exists: `link`
 
 error: cannot find attribute `lint` in this scope
-  --> $DIR/diagnostic-derive.rs:579:3
+  --> $DIR/diagnostic-derive.rs:584:3
    |
 LL | #[lint(typeck::ambiguous_lifetime_bound, code = "E0123")]
    |   ^^^^ help: a built-in attribute with a similar name exists: `link`
 
+error: cannot find attribute `multipart_suggestion` in this scope
+  --> $DIR/diagnostic-derive.rs:624:3
+   |
+LL | #[multipart_suggestion(typeck::suggestion)]
+   |   ^^^^^^^^^^^^^^^^^^^^
+
+error: cannot find attribute `multipart_suggestion` in this scope
+  --> $DIR/diagnostic-derive.rs:627:3
+   |
+LL | #[multipart_suggestion()]
+   |   ^^^^^^^^^^^^^^^^^^^^
+
+error: cannot find attribute `multipart_suggestion` in this scope
+  --> $DIR/diagnostic-derive.rs:631:7
+   |
+LL |     #[multipart_suggestion(typeck::suggestion)]
+   |       ^^^^^^^^^^^^^^^^^^^^
+
 error[E0425]: cannot find value `nonsense` in module `rustc_errors::fluent`
   --> $DIR/diagnostic-derive.rs:66:8
    |
@@ -446,20 +578,20 @@ LL | #[diag(nonsense, code = "E0123")]
    |        ^^^^^^^^ not found in `rustc_errors::fluent`
 
 error[E0277]: the trait bound `Hello: IntoDiagnosticArg` is not satisfied
-  --> $DIR/diagnostic-derive.rs:331:10
+  --> $DIR/diagnostic-derive.rs:336:10
    |
-LL | #[derive(SessionDiagnostic)]
-   |          ^^^^^^^^^^^^^^^^^ the trait `IntoDiagnosticArg` is not implemented for `Hello`
+LL | #[derive(Diagnostic)]
+   |          ^^^^^^^^^^ the trait `IntoDiagnosticArg` is not implemented for `Hello`
    |
    = help: normalized in stderr
 note: required by a bound in `DiagnosticBuilder::<'a, G>::set_arg`
-  --> $COMPILER_DIR/rustc_errors/src/diagnostic_builder.rs:569:19
+  --> $COMPILER_DIR/rustc_errors/src/diagnostic_builder.rs:LL:CC
    |
 LL |         arg: impl IntoDiagnosticArg,
    |                   ^^^^^^^^^^^^^^^^^ required by this bound in `DiagnosticBuilder::<'a, G>::set_arg`
-   = note: this error originates in the derive macro `SessionDiagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the derive macro `Diagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 55 previous errors
+error: aborting due to 72 previous errors
 
 Some errors have detailed explanations: E0277, E0425.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
index 89eaec78c6f1..606b3b5e5ebc 100644
--- a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
+++ b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
@@ -1,8 +1,8 @@
 // check-fail
-// Tests error conditions for specifying subdiagnostics using #[derive(SessionSubdiagnostic)]
+// Tests error conditions for specifying subdiagnostics using #[derive(Subdiagnostic)]
 
 // The proc_macro2 crate handles spans differently when on beta/stable release rather than nightly,
-// changing the output of this test. Since SessionSubdiagnostic is strictly internal to the compiler
+// changing the output of this test. Since Subdiagnostic is strictly internal to the compiler
 // the test is just ignored on stable and beta:
 // ignore-beta
 // ignore-stable
@@ -17,9 +17,9 @@ extern crate rustc_macros;
 
 use rustc_errors::Applicability;
 use rustc_span::Span;
-use rustc_macros::SessionSubdiagnostic;
+use rustc_macros::Subdiagnostic;
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct A {
     #[primary_span]
@@ -27,7 +27,7 @@ struct A {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum B {
     #[label(parser::add_paren)]
     A {
@@ -43,23 +43,23 @@ enum B {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 //~^ ERROR label without `#[primary_span]` field
 struct C {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label]
-//~^ ERROR `#[label]` is not a valid attribute
+//~^ ERROR diagnostic slug must be first argument
 struct D {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[foo]
 //~^ ERROR `#[foo]` is not a valid attribute
 //~^^ ERROR cannot find attribute `foo` in this scope
@@ -69,7 +69,7 @@ struct E {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label = "..."]
 //~^ ERROR `#[label = ...]` is not a valid attribute
 struct F {
@@ -78,43 +78,47 @@ struct F {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(bug = "...")]
 //~^ ERROR `#[label(bug = ...)]` is not a valid attribute
+//~| ERROR diagnostic slug must be first argument
 struct G {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label("...")]
 //~^ ERROR `#[label("...")]` is not a valid attribute
+//~| ERROR diagnostic slug must be first argument
 struct H {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(slug = 4)]
 //~^ ERROR `#[label(slug = ...)]` is not a valid attribute
+//~| ERROR diagnostic slug must be first argument
 struct J {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(slug("..."))]
 //~^ ERROR `#[label(slug(...))]` is not a valid attribute
+//~| ERROR diagnostic slug must be first argument
 struct K {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(slug)]
 //~^ ERROR cannot find value `slug` in module `rustc_errors::fluent`
 //~^^ NOTE not found in `rustc_errors::fluent`
@@ -124,7 +128,7 @@ struct L {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label()]
 //~^ ERROR diagnostic slug must be first argument of a `#[label(...)]` attribute
 struct M {
@@ -133,25 +137,25 @@ struct M {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren, code = "...")]
-//~^ ERROR `code` is not a valid nested attribute of a `label` attribute
+//~^ ERROR `#[label(code = ...)]` is not a valid attribute
 struct N {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren, applicability = "machine-applicable")]
-//~^ ERROR `applicability` is not a valid nested attribute of a `label` attribute
+//~^ ERROR `#[label(applicability = ...)]` is not a valid attribute
 struct O {
     #[primary_span]
     span: Span,
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[foo]
 //~^ ERROR cannot find attribute `foo` in this scope
 //~^^ ERROR unsupported type attribute for subdiagnostic enum
@@ -164,7 +168,7 @@ enum P {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum Q {
     #[bar]
     //~^ ERROR `#[bar]` is not a valid attribute
@@ -176,7 +180,7 @@ enum Q {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum R {
     #[bar = "..."]
     //~^ ERROR `#[bar = ...]` is not a valid attribute
@@ -188,7 +192,7 @@ enum R {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum S {
     #[bar = 4]
     //~^ ERROR `#[bar = ...]` is not a valid attribute
@@ -200,7 +204,7 @@ enum S {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum T {
     #[bar("...")]
     //~^ ERROR `#[bar(...)]` is not a valid attribute
@@ -212,10 +216,11 @@ enum T {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum U {
     #[label(code = "...")]
     //~^ ERROR diagnostic slug must be first argument of a `#[label(...)]` attribute
+    //~| ERROR `#[label(code = ...)]` is not a valid attribute
     A {
         #[primary_span]
         span: Span,
@@ -223,7 +228,7 @@ enum U {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum V {
     #[label(parser::add_paren)]
     A {
@@ -239,7 +244,7 @@ enum V {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 //~^ ERROR label without `#[primary_span]` field
 struct W {
@@ -248,7 +253,7 @@ struct W {
     span: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct X {
     #[primary_span]
@@ -258,7 +263,7 @@ struct X {
     applicability: Applicability,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct Y {
     #[primary_span]
@@ -269,7 +274,7 @@ struct Y {
     bar: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct Z {
     #[primary_span]
@@ -280,7 +285,7 @@ struct Z {
     bar: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct AA {
     #[primary_span]
@@ -291,7 +296,7 @@ struct AA {
     bar: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct AB {
     #[primary_span]
@@ -300,24 +305,22 @@ struct AB {
     z: Z
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 union AC {
 //~^ ERROR unexpected unsupported untagged union
     span: u32,
     b: u64
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
-//~^ NOTE previously specified here
 #[label(parser::add_paren)]
-//~^ ERROR specified multiple times
 struct AD {
     #[primary_span]
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren, parser::add_paren)]
 //~^ ERROR `#[label(parser::add_paren)]` is not a valid attribute
 struct AE {
@@ -325,7 +328,7 @@ struct AE {
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label(parser::add_paren)]
 struct AF {
     #[primary_span]
@@ -336,14 +339,14 @@ struct AF {
     span_b: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 struct AG {
     //~^ ERROR subdiagnostic kind not specified
     #[primary_span]
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...")]
 struct AH {
     #[primary_span]
@@ -353,7 +356,7 @@ struct AH {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum AI {
     #[suggestion(parser::add_paren, code = "...")]
     A {
@@ -373,7 +376,7 @@ enum AI {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...", code = "...")]
 //~^ ERROR specified multiple times
 //~^^ NOTE previously specified here
@@ -384,7 +387,7 @@ struct AJ {
     applicability: Applicability,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...")]
 struct AK {
     #[primary_span]
@@ -397,7 +400,7 @@ struct AK {
     applicability_b: Applicability,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...")]
 struct AL {
     #[primary_span]
@@ -407,14 +410,14 @@ struct AL {
     applicability: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...")]
 struct AM {
     #[primary_span]
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren)]
 //~^ ERROR suggestion without `code = "..."`
 struct AN {
@@ -424,7 +427,7 @@ struct AN {
     applicability: Applicability,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code ="...", applicability = "foo")]
 //~^ ERROR invalid applicability
 struct AO {
@@ -432,31 +435,31 @@ struct AO {
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[help(parser::add_paren)]
 struct AP {
     var: String
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[note(parser::add_paren)]
 struct AQ;
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...")]
 //~^ ERROR suggestion without `#[primary_span]` field
 struct AR {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code ="...", applicability = "machine-applicable")]
 struct AS {
     #[primary_span]
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[label]
 //~^ ERROR unsupported type attribute for subdiagnostic enum
 enum AT {
@@ -468,7 +471,7 @@ enum AT {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
 struct AU {
     #[primary_span]
@@ -476,7 +479,7 @@ struct AU {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
 //~^ ERROR `var` doesn't refer to a field on this type
 struct AV {
@@ -484,7 +487,7 @@ struct AV {
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum AW {
     #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
     A {
@@ -494,7 +497,7 @@ enum AW {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 enum AX {
     #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
 //~^ ERROR `var` doesn't refer to a field on this type
@@ -504,18 +507,18 @@ enum AX {
     }
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[warning(parser::add_paren)]
 struct AY {}
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[warning(parser::add_paren)]
 struct AZ {
     #[primary_span]
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[suggestion(parser::add_paren, code = "...")]
 //~^ ERROR suggestion without `#[primary_span]` field
 struct BA {
@@ -530,15 +533,15 @@ struct BA {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, code = "...", applicability = "machine-applicable")]
 //~^ ERROR multipart suggestion without any `#[suggestion_part(...)]` fields
-//~| ERROR `code` is not a valid nested attribute of a `multipart_suggestion` attribute
+//~| ERROR `#[multipart_suggestion(code = ...)]` is not a valid attribute
 struct BBa {
     var: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
 struct BBb {
     #[suggestion_part]
@@ -546,7 +549,7 @@ struct BBb {
     span1: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
 struct BBc {
     #[suggestion_part()]
@@ -554,7 +557,7 @@ struct BBc {
     span1: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren)]
 //~^ ERROR multipart suggestion without any `#[suggestion_part(...)]` fields
 struct BC {
@@ -563,7 +566,7 @@ struct BC {
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren)]
 struct BD {
     #[suggestion_part]
@@ -583,7 +586,7 @@ struct BD {
     s2: String,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
 struct BE {
     #[suggestion_part(code = "...", code = ",,,")]
@@ -592,7 +595,7 @@ struct BE {
     span: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
 struct BF {
     #[suggestion_part(code = "(")]
@@ -601,7 +604,7 @@ struct BF {
     second: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren)]
 struct BG {
     #[applicability]
@@ -612,12 +615,11 @@ struct BG {
     second: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
-//~^ NOTE previously specified here
 struct BH {
     #[applicability]
-    //~^ ERROR specified multiple times
+    //~^ ERROR `#[applicability]` has no effect
     appl: Applicability,
     #[suggestion_part(code = "(")]
     first: Span,
@@ -625,7 +627,7 @@ struct BH {
     second: Span,
 }
 
-#[derive(SessionSubdiagnostic)]
+#[derive(Subdiagnostic)]
 #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
 struct BI {
     #[suggestion_part(code = "")]
diff --git a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
index 75a34f44bbe7..171b89e657d8 100644
--- a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
+++ b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
@@ -8,7 +8,7 @@ LL | |     var: String,
 LL | | }
    | |_^
 
-error: `#[label]` is not a valid attribute
+error: diagnostic slug must be first argument of a `#[label(...)]` attribute
   --> $DIR/subdiagnostic-derive.rs:54:1
    |
 LL | #[label]
@@ -31,101 +31,123 @@ error: `#[label(bug = ...)]` is not a valid attribute
    |
 LL | #[label(bug = "...")]
    |         ^^^^^^^^^^^
+
+error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+  --> $DIR/subdiagnostic-derive.rs:82:1
    |
-   = help: first argument of the attribute should be the diagnostic slug
+LL | #[label(bug = "...")]
+   | ^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[label("...")]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:91:9
+  --> $DIR/subdiagnostic-derive.rs:92:9
    |
 LL | #[label("...")]
    |         ^^^^^
+
+error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+  --> $DIR/subdiagnostic-derive.rs:92:1
    |
-   = help: first argument of the attribute should be the diagnostic slug
+LL | #[label("...")]
+   | ^^^^^^^^^^^^^^^
 
 error: `#[label(slug = ...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:100:9
+  --> $DIR/subdiagnostic-derive.rs:102:9
    |
 LL | #[label(slug = 4)]
    |         ^^^^^^^^
+
+error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+  --> $DIR/subdiagnostic-derive.rs:102:1
    |
-   = help: first argument of the attribute should be the diagnostic slug
+LL | #[label(slug = 4)]
+   | ^^^^^^^^^^^^^^^^^^
 
 error: `#[label(slug(...))]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:109:9
+  --> $DIR/subdiagnostic-derive.rs:112:9
    |
 LL | #[label(slug("..."))]
    |         ^^^^^^^^^^^
-   |
-   = help: first argument of the attribute should be the diagnostic slug
 
 error: diagnostic slug must be first argument of a `#[label(...)]` attribute
-  --> $DIR/subdiagnostic-derive.rs:128:1
+  --> $DIR/subdiagnostic-derive.rs:112:1
+   |
+LL | #[label(slug("..."))]
+   | ^^^^^^^^^^^^^^^^^^^^^
+
+error: diagnostic slug must be first argument of a `#[label(...)]` attribute
+  --> $DIR/subdiagnostic-derive.rs:132:1
    |
 LL | #[label()]
    | ^^^^^^^^^^
 
-error: `code` is not a valid nested attribute of a `label` attribute
-  --> $DIR/subdiagnostic-derive.rs:137:28
+error: `#[label(code = ...)]` is not a valid attribute
+  --> $DIR/subdiagnostic-derive.rs:141:28
    |
 LL | #[label(parser::add_paren, code = "...")]
    |                            ^^^^^^^^^^^^
 
-error: `applicability` is not a valid nested attribute of a `label` attribute
-  --> $DIR/subdiagnostic-derive.rs:146:28
+error: `#[label(applicability = ...)]` is not a valid attribute
+  --> $DIR/subdiagnostic-derive.rs:150:28
    |
 LL | #[label(parser::add_paren, applicability = "machine-applicable")]
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: unsupported type attribute for subdiagnostic enum
-  --> $DIR/subdiagnostic-derive.rs:155:1
+  --> $DIR/subdiagnostic-derive.rs:159:1
    |
 LL | #[foo]
    | ^^^^^^
 
 error: `#[bar]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:169:5
+  --> $DIR/subdiagnostic-derive.rs:173:5
    |
 LL |     #[bar]
    |     ^^^^^^
 
 error: `#[bar = ...]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:181:5
+  --> $DIR/subdiagnostic-derive.rs:185:5
    |
 LL |     #[bar = "..."]
    |     ^^^^^^^^^^^^^^
 
 error: `#[bar = ...]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:193:5
+  --> $DIR/subdiagnostic-derive.rs:197:5
    |
 LL |     #[bar = 4]
    |     ^^^^^^^^^^
 
 error: `#[bar(...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:205:5
+  --> $DIR/subdiagnostic-derive.rs:209:5
    |
 LL |     #[bar("...")]
    |     ^^^^^^^^^^^^^
 
+error: `#[label(code = ...)]` is not a valid attribute
+  --> $DIR/subdiagnostic-derive.rs:221:13
+   |
+LL |     #[label(code = "...")]
+   |             ^^^^^^^^^^^^
+
 error: diagnostic slug must be first argument of a `#[label(...)]` attribute
-  --> $DIR/subdiagnostic-derive.rs:217:5
+  --> $DIR/subdiagnostic-derive.rs:221:5
    |
 LL |     #[label(code = "...")]
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error: subdiagnostic kind not specified
-  --> $DIR/subdiagnostic-derive.rs:234:5
+  --> $DIR/subdiagnostic-derive.rs:239:5
    |
 LL |     B {
    |     ^
 
 error: the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/subdiagnostic-derive.rs:246:5
+  --> $DIR/subdiagnostic-derive.rs:251:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
 
 error: label without `#[primary_span]` field
-  --> $DIR/subdiagnostic-derive.rs:243:1
+  --> $DIR/subdiagnostic-derive.rs:248:1
    |
 LL | / #[label(parser::add_paren)]
 LL | |
@@ -137,13 +159,13 @@ LL | | }
    | |_^
 
 error: `#[applicability]` is only valid on suggestions
-  --> $DIR/subdiagnostic-derive.rs:256:5
+  --> $DIR/subdiagnostic-derive.rs:261:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
 error: `#[bar]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:266:5
+  --> $DIR/subdiagnostic-derive.rs:271:5
    |
 LL |     #[bar]
    |     ^^^^^^
@@ -151,13 +173,13 @@ LL |     #[bar]
    = help: only `primary_span`, `applicability` and `skip_arg` are valid field attributes
 
 error: `#[bar = ...]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:277:5
+  --> $DIR/subdiagnostic-derive.rs:282:5
    |
 LL |     #[bar = "..."]
    |     ^^^^^^^^^^^^^^
 
 error: `#[bar(...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:288:5
+  --> $DIR/subdiagnostic-derive.rs:293:5
    |
 LL |     #[bar("...")]
    |     ^^^^^^^^^^^^^
@@ -165,7 +187,7 @@ LL |     #[bar("...")]
    = help: only `primary_span`, `applicability` and `skip_arg` are valid field attributes
 
 error: unexpected unsupported untagged union
-  --> $DIR/subdiagnostic-derive.rs:304:1
+  --> $DIR/subdiagnostic-derive.rs:309:1
    |
 LL | / union AC {
 LL | |
@@ -174,20 +196,8 @@ LL | |     b: u64
 LL | | }
    | |_^
 
-error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:313:1
-   |
-LL | #[label(parser::add_paren)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:311:1
-   |
-LL | #[label(parser::add_paren)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
 error: `#[label(parser::add_paren)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:321:28
+  --> $DIR/subdiagnostic-derive.rs:324:28
    |
 LL | #[label(parser::add_paren, parser::add_paren)]
    |                            ^^^^^^^^^^^^^^^^^
@@ -195,67 +205,67 @@ LL | #[label(parser::add_paren, parser::add_paren)]
    = help: a diagnostic slug must be the first argument to the attribute
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:334:5
+  --> $DIR/subdiagnostic-derive.rs:337:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:331:5
+  --> $DIR/subdiagnostic-derive.rs:334:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
 
 error: subdiagnostic kind not specified
-  --> $DIR/subdiagnostic-derive.rs:340:8
+  --> $DIR/subdiagnostic-derive.rs:343:8
    |
 LL | struct AG {
    |        ^^
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:377:47
+  --> $DIR/subdiagnostic-derive.rs:380:47
    |
 LL | #[suggestion(parser::add_paren, code = "...", code = "...")]
    |                                               ^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:377:33
+  --> $DIR/subdiagnostic-derive.rs:380:33
    |
 LL | #[suggestion(parser::add_paren, code = "...", code = "...")]
    |                                 ^^^^^^^^^^^^
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:395:5
+  --> $DIR/subdiagnostic-derive.rs:398:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:392:5
+  --> $DIR/subdiagnostic-derive.rs:395:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
 error: the `#[applicability]` attribute can only be applied to fields of type `Applicability`
-  --> $DIR/subdiagnostic-derive.rs:405:5
+  --> $DIR/subdiagnostic-derive.rs:408:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
 error: suggestion without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:418:1
+  --> $DIR/subdiagnostic-derive.rs:421:1
    |
 LL | #[suggestion(parser::add_paren)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: invalid applicability
-  --> $DIR/subdiagnostic-derive.rs:428:46
+  --> $DIR/subdiagnostic-derive.rs:431:46
    |
 LL | #[suggestion(parser::add_paren, code ="...", applicability = "foo")]
    |                                              ^^^^^^^^^^^^^^^^^^^^^
 
 error: suggestion without `#[primary_span]` field
-  --> $DIR/subdiagnostic-derive.rs:446:1
+  --> $DIR/subdiagnostic-derive.rs:449:1
    |
 LL | / #[suggestion(parser::add_paren, code = "...")]
 LL | |
@@ -265,25 +275,25 @@ LL | | }
    | |_^
 
 error: unsupported type attribute for subdiagnostic enum
-  --> $DIR/subdiagnostic-derive.rs:460:1
+  --> $DIR/subdiagnostic-derive.rs:463:1
    |
 LL | #[label]
    | ^^^^^^^^
 
 error: `var` doesn't refer to a field on this type
-  --> $DIR/subdiagnostic-derive.rs:480:39
+  --> $DIR/subdiagnostic-derive.rs:483:39
    |
 LL | #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
    |                                       ^^^^^^^
 
 error: `var` doesn't refer to a field on this type
-  --> $DIR/subdiagnostic-derive.rs:499:43
+  --> $DIR/subdiagnostic-derive.rs:502:43
    |
 LL |     #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
    |                                           ^^^^^^^
 
 error: `#[suggestion_part]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:522:5
+  --> $DIR/subdiagnostic-derive.rs:525:5
    |
 LL |     #[suggestion_part]
    |     ^^^^^^^^^^^^^^^^^^
@@ -291,7 +301,7 @@ LL |     #[suggestion_part]
    = help: `#[suggestion_part(...)]` is only valid in multipart suggestions, use `#[primary_span]` instead
 
 error: `#[suggestion_part(...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:525:5
+  --> $DIR/subdiagnostic-derive.rs:528:5
    |
 LL |     #[suggestion_part(code = "...")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -299,7 +309,7 @@ LL |     #[suggestion_part(code = "...")]
    = help: `#[suggestion_part(...)]` is only valid in multipart suggestions
 
 error: suggestion without `#[primary_span]` field
-  --> $DIR/subdiagnostic-derive.rs:519:1
+  --> $DIR/subdiagnostic-derive.rs:522:1
    |
 LL | / #[suggestion(parser::add_paren, code = "...")]
 LL | |
@@ -310,14 +320,16 @@ LL | |     var: String,
 LL | | }
    | |_^
 
-error: `code` is not a valid nested attribute of a `multipart_suggestion` attribute
-  --> $DIR/subdiagnostic-derive.rs:534:43
+error: `#[multipart_suggestion(code = ...)]` is not a valid attribute
+  --> $DIR/subdiagnostic-derive.rs:537:43
    |
 LL | #[multipart_suggestion(parser::add_paren, code = "...", applicability = "machine-applicable")]
    |                                           ^^^^^^^^^^^^
+   |
+   = help: only `applicability` is a valid nested attributes
 
 error: multipart suggestion without any `#[suggestion_part(...)]` fields
-  --> $DIR/subdiagnostic-derive.rs:534:1
+  --> $DIR/subdiagnostic-derive.rs:537:1
    |
 LL | / #[multipart_suggestion(parser::add_paren, code = "...", applicability = "machine-applicable")]
 LL | |
@@ -328,19 +340,19 @@ LL | | }
    | |_^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:544:5
+  --> $DIR/subdiagnostic-derive.rs:547:5
    |
 LL |     #[suggestion_part]
    |     ^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:552:5
+  --> $DIR/subdiagnostic-derive.rs:555:5
    |
 LL |     #[suggestion_part()]
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: `#[primary_span]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:561:5
+  --> $DIR/subdiagnostic-derive.rs:564:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
@@ -348,7 +360,7 @@ LL |     #[primary_span]
    = help: multipart suggestions use one or more `#[suggestion_part]`s rather than one `#[primary_span]`
 
 error: multipart suggestion without any `#[suggestion_part(...)]` fields
-  --> $DIR/subdiagnostic-derive.rs:558:1
+  --> $DIR/subdiagnostic-derive.rs:561:1
    |
 LL | / #[multipart_suggestion(parser::add_paren)]
 LL | |
@@ -360,19 +372,19 @@ LL | | }
    | |_^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:569:5
+  --> $DIR/subdiagnostic-derive.rs:572:5
    |
 LL |     #[suggestion_part]
    |     ^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:572:5
+  --> $DIR/subdiagnostic-derive.rs:575:5
    |
 LL |     #[suggestion_part()]
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion_part(foo = ...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:575:23
+  --> $DIR/subdiagnostic-derive.rs:578:23
    |
 LL |     #[suggestion_part(foo = "bar")]
    |                       ^^^^^^^^^^^
@@ -380,40 +392,34 @@ LL |     #[suggestion_part(foo = "bar")]
    = help: `code` is the only valid nested attribute
 
 error: the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/subdiagnostic-derive.rs:578:5
+  --> $DIR/subdiagnostic-derive.rs:581:5
    |
 LL |     #[suggestion_part(code = "...")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/subdiagnostic-derive.rs:581:5
+  --> $DIR/subdiagnostic-derive.rs:584:5
    |
 LL |     #[suggestion_part()]
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:589:37
+  --> $DIR/subdiagnostic-derive.rs:592:37
    |
 LL |     #[suggestion_part(code = "...", code = ",,,")]
    |                                     ^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:589:23
+  --> $DIR/subdiagnostic-derive.rs:592:23
    |
 LL |     #[suggestion_part(code = "...", code = ",,,")]
    |                       ^^^^^^^^^^^^
 
-error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:619:5
+error: `#[applicability]` has no effect if all `#[suggestion]`/`#[multipart_suggestion]` attributes have a static `applicability = "..."`
+  --> $DIR/subdiagnostic-derive.rs:621:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
-   |
-note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:616:43
-   |
-LL | #[multipart_suggestion(parser::add_paren, applicability = "machine-applicable")]
-   |                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: cannot find attribute `foo` in this scope
   --> $DIR/subdiagnostic-derive.rs:63:3
@@ -422,59 +428,59 @@ LL | #[foo]
    |   ^^^
 
 error: cannot find attribute `foo` in this scope
-  --> $DIR/subdiagnostic-derive.rs:155:3
+  --> $DIR/subdiagnostic-derive.rs:159:3
    |
 LL | #[foo]
    |   ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:169:7
+  --> $DIR/subdiagnostic-derive.rs:173:7
    |
 LL |     #[bar]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:181:7
+  --> $DIR/subdiagnostic-derive.rs:185:7
    |
 LL |     #[bar = "..."]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:193:7
+  --> $DIR/subdiagnostic-derive.rs:197:7
    |
 LL |     #[bar = 4]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:205:7
+  --> $DIR/subdiagnostic-derive.rs:209:7
    |
 LL |     #[bar("...")]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:266:7
+  --> $DIR/subdiagnostic-derive.rs:271:7
    |
 LL |     #[bar]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:277:7
+  --> $DIR/subdiagnostic-derive.rs:282:7
    |
 LL |     #[bar = "..."]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:288:7
+  --> $DIR/subdiagnostic-derive.rs:293:7
    |
 LL |     #[bar("...")]
    |       ^^^
 
 error[E0425]: cannot find value `slug` in module `rustc_errors::fluent`
-  --> $DIR/subdiagnostic-derive.rs:118:9
+  --> $DIR/subdiagnostic-derive.rs:122:9
    |
 LL | #[label(slug)]
    |         ^^^^ not found in `rustc_errors::fluent`
 
-error: aborting due to 64 previous errors
+error: aborting due to 68 previous errors
 
 For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/abi/abi-typo-unstable.rs b/src/test/ui/abi/abi-typo-unstable.rs
new file mode 100644
index 000000000000..94991a5eb17e
--- /dev/null
+++ b/src/test/ui/abi/abi-typo-unstable.rs
@@ -0,0 +1,6 @@
+// rust-intrinsic is unstable and not enabled, so it should not be suggested as a fix
+extern "rust-intrinsec" fn rust_intrinsic() {} //~ ERROR invalid ABI
+
+fn main() {
+    rust_intrinsic();
+}
diff --git a/src/test/ui/abi/abi-typo-unstable.stderr b/src/test/ui/abi/abi-typo-unstable.stderr
new file mode 100644
index 000000000000..3b346e00227a
--- /dev/null
+++ b/src/test/ui/abi/abi-typo-unstable.stderr
@@ -0,0 +1,11 @@
+error[E0703]: invalid ABI: found `rust-intrinsec`
+  --> $DIR/abi-typo-unstable.rs:2:8
+   |
+LL | extern "rust-intrinsec" fn rust_intrinsic() {}
+   |        ^^^^^^^^^^^^^^^^ invalid ABI
+   |
+   = note: invoke `rustc --print=calling-conventions` for a full list of supported calling conventions.
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0703`.
diff --git a/src/test/ui/abi/issues/issue-97463-broken-abi-leaked-uninit-data.rs b/src/test/ui/abi/issues/issue-97463-broken-abi-leaked-uninit-data.rs
new file mode 100644
index 000000000000..fba880d4f9a5
--- /dev/null
+++ b/src/test/ui/abi/issues/issue-97463-broken-abi-leaked-uninit-data.rs
@@ -0,0 +1,39 @@
+// run-pass
+// ignore-wasm
+#![allow(dead_code)]
+#![allow(improper_ctypes)]
+
+#[link(name = "rust_test_helpers", kind = "static")]
+extern "C" {
+    pub fn issue_97463_leak_uninit_data(a: u32, b: u32, c: u32) -> u16;
+}
+
+fn main() {
+    const C1: usize = 0x327b23c6;
+    const C2: usize = C1 & 0xFFFF;
+
+    let r1: usize = 0x0;
+    let r2: usize = C1;
+    let r3: usize = 0x0;
+    let value: u16 = unsafe { issue_97463_leak_uninit_data(r1 as u32, r2 as u32, r3 as u32) };
+
+    // NOTE: as an example of the sensitivity of this test to optimization choices,
+    // uncommenting this block of code makes the bug go away on pnkfelix's machine.
+    // (But observing via `dbg!` doesn't hide the bug. At least sometimes.)
+    /*
+    println!("{}", value);
+    println!("{}", value as usize);
+    println!("{}", usize::from(value));
+    println!("{}", (value as usize) & 0xFFFF);
+     */
+
+    let d1 = value;
+    let d2 = value as usize;
+    let d3 = usize::from(value);
+    let d4 = (value as usize) & 0xFFFF;
+
+    let d = (&d1, &d2, &d3, &d4);
+    let d_ = (d1, d2, d3, d4);
+
+    assert_eq!(((&(C2 as u16), &C2, &C2, &C2), (C2 as u16, C2, C2, C2)), (d, d_));
+}
diff --git a/src/test/ui/abi/segfault-no-out-of-stack.rs b/src/test/ui/abi/segfault-no-out-of-stack.rs
index ad4faf95a0f9..ab2b30894850 100644
--- a/src/test/ui/abi/segfault-no-out-of-stack.rs
+++ b/src/test/ui/abi/segfault-no-out-of-stack.rs
@@ -3,6 +3,7 @@
 #![allow(unused_imports)]
 // ignore-emscripten can't run commands
 // ignore-sgx no processes
+// ignore-fuchsia must translate zircon signal to SIGSEGV/SIGBUS, FIXME (#58590)
 #![feature(rustc_private)]
 
 extern crate libc;
diff --git a/src/test/ui/abi/stack-probes-lto.rs b/src/test/ui/abi/stack-probes-lto.rs
index 90df1f3f53e8..74b5e843f774 100644
--- a/src/test/ui/abi/stack-probes-lto.rs
+++ b/src/test/ui/abi/stack-probes-lto.rs
@@ -12,6 +12,7 @@
 // ignore-sgx no processes
 // ignore-musl FIXME #31506
 // ignore-pretty
+// ignore-fuchsia no exception handler registered for segfault
 // compile-flags: -C lto
 // no-prefer-dynamic
 
diff --git a/src/test/ui/abi/stack-probes.rs b/src/test/ui/abi/stack-probes.rs
index e998dd0f83eb..b497af7abad5 100644
--- a/src/test/ui/abi/stack-probes.rs
+++ b/src/test/ui/abi/stack-probes.rs
@@ -10,6 +10,7 @@
 // ignore-wasm
 // ignore-emscripten no processes
 // ignore-sgx no processes
+// ignore-fuchsia no exception handler registered for segfault
 
 use std::env;
 use std::mem::MaybeUninit;
diff --git a/src/test/ui/allocator/no_std-alloc-error-handler-custom.rs b/src/test/ui/allocator/no_std-alloc-error-handler-custom.rs
index 54b7c8bb9c6f..851da231a734 100644
--- a/src/test/ui/allocator/no_std-alloc-error-handler-custom.rs
+++ b/src/test/ui/allocator/no_std-alloc-error-handler-custom.rs
@@ -86,7 +86,7 @@ fn panic(panic_info: &core::panic::PanicInfo) -> ! {
 
 // Because we are compiling this code with `-C panic=abort`, this wouldn't normally be needed.
 // However, `core` and `alloc` are both compiled with `-C panic=unwind`, which means that functions
-// in these libaries will refer to `rust_eh_personality` if LLVM can not *prove* the contents won't
+// in these libraries will refer to `rust_eh_personality` if LLVM can not *prove* the contents won't
 // unwind. So, for this test case we will define the symbol.
 #[lang = "eh_personality"]
 extern fn rust_eh_personality() {}
diff --git a/src/test/ui/allocator/no_std-alloc-error-handler-default.rs b/src/test/ui/allocator/no_std-alloc-error-handler-default.rs
index ffa331a992c8..30ce0f162c7a 100644
--- a/src/test/ui/allocator/no_std-alloc-error-handler-default.rs
+++ b/src/test/ui/allocator/no_std-alloc-error-handler-default.rs
@@ -73,7 +73,7 @@ fn panic(panic_info: &core::panic::PanicInfo) -> ! {
 
 // Because we are compiling this code with `-C panic=abort`, this wouldn't normally be needed.
 // However, `core` and `alloc` are both compiled with `-C panic=unwind`, which means that functions
-// in these libaries will refer to `rust_eh_personality` if LLVM can not *prove* the contents won't
+// in these libraries will refer to `rust_eh_personality` if LLVM can not *prove* the contents won't
 // unwind. So, for this test case we will define the symbol.
 #[lang = "eh_personality"]
 extern fn rust_eh_personality() {}
diff --git a/src/test/ui/anonymous-higher-ranked-lifetime.stderr b/src/test/ui/anonymous-higher-ranked-lifetime.stderr
index 1a0a5fdf4eb2..bf5f642ca823 100644
--- a/src/test/ui/anonymous-higher-ranked-lifetime.stderr
+++ b/src/test/ui/anonymous-higher-ranked-lifetime.stderr
@@ -6,7 +6,7 @@ LL |     f1(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'r, 's> fn(&'r (), &'s ()) -> _`
+   = note: expected closure signature `for<'a, 'b> fn(&'a (), &'b ()) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `f1`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:16:25
@@ -22,7 +22,7 @@ LL |     f2(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'a, 'r> fn(&'a (), &'r ()) -> _`
+   = note: expected closure signature `for<'a, 'b> fn(&'a (), &'b ()) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `f2`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:17:25
@@ -38,7 +38,7 @@ LL |     f3(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'r> fn(&(), &'r ()) -> _`
+   = note: expected closure signature `for<'a> fn(&(), &'a ()) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `f3`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:18:29
@@ -54,7 +54,7 @@ LL |     f4(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'r, 's> fn(&'s (), &'r ()) -> _`
+   = note: expected closure signature `for<'r, 'a> fn(&'a (), &'r ()) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `f4`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:19:25
@@ -86,7 +86,7 @@ LL |     g1(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'r> fn(&'r (), Box<(dyn for<'r> Fn(&'r ()) + 'static)>) -> _`
+   = note: expected closure signature `for<'a> fn(&'a (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `g1`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:23:25
@@ -102,7 +102,7 @@ LL |     g2(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'r> fn(&'r (), for<'r> fn(&'r ())) -> _`
+   = note: expected closure signature `for<'a> fn(&'a (), for<'a> fn(&'a ())) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `g2`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:24:25
@@ -118,7 +118,7 @@ LL |     g3(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'s> fn(&'s (), Box<(dyn for<'r> Fn(&'r ()) + 'static)>) -> _`
+   = note: expected closure signature `for<'s> fn(&'s (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `g3`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:25:25
@@ -134,7 +134,7 @@ LL |     g4(|_: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'s> fn(&'s (), for<'r> fn(&'r ())) -> _`
+   = note: expected closure signature `for<'a> fn(&'a (), for<'r> fn(&'r ())) -> _`
               found closure signature `fn((), ()) -> _`
 note: required by a bound in `g4`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:26:25
@@ -150,7 +150,7 @@ LL |     h1(|_: (), _: (), _: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'r, 's> fn(&'r (), Box<(dyn for<'r> Fn(&'r ()) + 'static)>, &'s (), for<'r, 's> fn(&'r (), &'s ())) -> _`
+   = note: expected closure signature `for<'a, 'b> fn(&'a (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>, &'b (), for<'a, 'b> fn(&'a (), &'b ())) -> _`
               found closure signature `fn((), (), (), ()) -> _`
 note: required by a bound in `h1`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:29:25
@@ -166,7 +166,7 @@ LL |     h2(|_: (), _: (), _: (), _: ()| {});
    |     |
    |     expected due to this
    |
-   = note: expected closure signature `for<'t0, 'r> fn(&'r (), Box<(dyn for<'r> Fn(&'r ()) + 'static)>, &'t0 (), for<'r, 's> fn(&'r (), &'s ())) -> _`
+   = note: expected closure signature `for<'t0, 'a> fn(&'a (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>, &'t0 (), for<'a, 'b> fn(&'a (), &'b ())) -> _`
               found closure signature `fn((), (), (), ()) -> _`
 note: required by a bound in `h2`
   --> $DIR/anonymous-higher-ranked-lifetime.rs:30:25
diff --git a/src/test/ui/argument-suggestions/basic.stderr b/src/test/ui/argument-suggestions/basic.stderr
index c495ad6b842f..b118ce1bd0ea 100644
--- a/src/test/ui/argument-suggestions/basic.stderr
+++ b/src/test/ui/argument-suggestions/basic.stderr
@@ -26,7 +26,7 @@ LL | fn extra() {}
 help: remove the extra argument
    |
 LL |     extra();
-   |     ~~~~~~~
+   |          ~~
 
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/basic.rs:22:5
@@ -42,7 +42,7 @@ LL | fn missing(_i: u32) {}
 help: provide the argument
    |
 LL |     missing(/* u32 */);
-   |     ~~~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/basic.rs:23:5
@@ -60,7 +60,7 @@ LL | fn swapped(_i: u32, _s: &str) {}
 help: swap these arguments
    |
 LL |     swapped(1, "");
-   |     ~~~~~~~~~~~~~~
+   |            ~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/basic.rs:24:5
@@ -79,7 +79,7 @@ LL | fn permuted(_x: X, _y: Y, _z: Z) {}
 help: reorder these arguments
    |
 LL |     permuted(X {}, Y {}, Z {});
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~
 
 error[E0057]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/basic.rs:27:5
@@ -95,7 +95,7 @@ LL |     let closure = |x| x;
 help: provide the argument
    |
 LL |     closure(/* value */);
-   |     ~~~~~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~~~
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/argument-suggestions/complex.stderr b/src/test/ui/argument-suggestions/complex.stderr
index bf49e7444583..205a852983a3 100644
--- a/src/test/ui/argument-suggestions/complex.stderr
+++ b/src/test/ui/argument-suggestions/complex.stderr
@@ -12,7 +12,7 @@ LL | fn complex(_i: u32, _s: &str, _e: E, _f: F, _g: G, _x: X, _y: Y, _z: Z ) {}
 help: did you mean
    |
 LL |   complex(/* u32 */, &"", /* E */, F::X2, G{}, X {}, Y {}, Z {});
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/exotic-calls.stderr b/src/test/ui/argument-suggestions/exotic-calls.stderr
index ca93ecc4e381..0580e53c510a 100644
--- a/src/test/ui/argument-suggestions/exotic-calls.stderr
+++ b/src/test/ui/argument-suggestions/exotic-calls.stderr
@@ -12,7 +12,7 @@ LL | fn foo<T: Fn()>(t: T) {
 help: remove the extra argument
    |
 LL |     t();
-   |     ~~~
+   |      ~~
 
 error[E0057]: this function takes 0 arguments but 1 argument was supplied
   --> $DIR/exotic-calls.rs:7:5
@@ -28,7 +28,7 @@ LL | fn bar(t: impl Fn()) {
 help: remove the extra argument
    |
 LL |     t();
-   |     ~~~
+   |      ~~
 
 error[E0057]: this function takes 0 arguments but 1 argument was supplied
   --> $DIR/exotic-calls.rs:16:5
@@ -44,7 +44,7 @@ LL | fn baz() -> impl Fn() {
 help: remove the extra argument
    |
 LL |     baz()()
-   |
+   |          ~~
 
 error[E0057]: this function takes 0 arguments but 1 argument was supplied
   --> $DIR/exotic-calls.rs:22:5
@@ -60,7 +60,7 @@ LL |     let x = || {};
 help: remove the extra argument
    |
 LL |     x();
-   |     ~~~
+   |      ~~
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/argument-suggestions/extra_arguments.stderr b/src/test/ui/argument-suggestions/extra_arguments.stderr
index 32b1e15737ab..48787b0c352c 100644
--- a/src/test/ui/argument-suggestions/extra_arguments.stderr
+++ b/src/test/ui/argument-suggestions/extra_arguments.stderr
@@ -12,7 +12,7 @@ LL | fn empty() {}
 help: remove the extra argument
    |
 LL |   empty();
-   |   ~~~~~~~
+   |        ~~
 
 error[E0061]: this function takes 1 argument but 2 arguments were supplied
   --> $DIR/extra_arguments.rs:9:3
@@ -28,7 +28,7 @@ LL | fn one_arg(_a: i32) {}
 help: remove the extra argument
    |
 LL |   one_arg(1);
-   |   ~~~~~~~~~~
+   |          ~~~
 
 error[E0061]: this function takes 1 argument but 2 arguments were supplied
   --> $DIR/extra_arguments.rs:10:3
@@ -44,7 +44,7 @@ LL | fn one_arg(_a: i32) {}
 help: remove the extra argument
    |
 LL |   one_arg(1);
-   |   ~~~~~~~~~~
+   |          ~~~
 
 error[E0061]: this function takes 1 argument but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:11:3
@@ -62,7 +62,7 @@ LL | fn one_arg(_a: i32) {}
 help: remove the extra arguments
    |
 LL |   one_arg(1);
-   |   ~~~~~~~~~~
+   |          ~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:13:3
@@ -78,7 +78,7 @@ LL | fn two_arg_same(_a: i32, _b: i32) {}
 help: remove the extra argument
    |
 LL |   two_arg_same(1, 1);
-   |   ~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:14:3
@@ -94,7 +94,7 @@ LL | fn two_arg_same(_a: i32, _b: i32) {}
 help: remove the extra argument
    |
 LL |   two_arg_same(1, 1);
-   |   ~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:16:3
@@ -110,7 +110,7 @@ LL | fn two_arg_diff(_a: i32, _b: &str) {}
 help: remove the extra argument
    |
 LL |   two_arg_diff(1, "");
-   |   ~~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:17:3
@@ -126,7 +126,7 @@ LL | fn two_arg_diff(_a: i32, _b: &str) {}
 help: remove the extra argument
    |
 LL |   two_arg_diff(1, "");
-   |   ~~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 4 arguments were supplied
   --> $DIR/extra_arguments.rs:18:3
@@ -144,7 +144,7 @@ LL | fn two_arg_diff(_a: i32, _b: &str) {}
 help: remove the extra arguments
    |
 LL |   two_arg_diff(1, "");
-   |   ~~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 4 arguments were supplied
   --> $DIR/extra_arguments.rs:19:3
@@ -162,7 +162,7 @@ LL | fn two_arg_diff(_a: i32, _b: &str) {}
 help: remove the extra arguments
    |
 LL |   two_arg_diff(1, "");
-   |   ~~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:22:3
@@ -178,7 +178,7 @@ LL | fn two_arg_same(_a: i32, _b: i32) {}
 help: remove the extra argument
    |
 LL |   two_arg_same(1, 1);
-   |   ~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:23:3
@@ -194,7 +194,7 @@ LL | fn two_arg_diff(_a: i32, _b: &str) {}
 help: remove the extra argument
    |
 LL |   two_arg_diff(1, "");
-   |   ~~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:24:3
@@ -213,7 +213,7 @@ LL | fn two_arg_same(_a: i32, _b: i32) {}
 help: remove the extra argument
    |
 LL |   two_arg_same(1, 1);
-   |   ~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~
 
 error[E0061]: this function takes 2 arguments but 3 arguments were supplied
   --> $DIR/extra_arguments.rs:30:3
@@ -232,7 +232,7 @@ LL | fn two_arg_diff(_a: i32, _b: &str) {}
 help: remove the extra argument
    |
 LL |   two_arg_diff(1, "");
-   |   ~~~~~~~~~~~~~~~~~~~
+   |               ~~~~~~~
 
 error: aborting due to 14 previous errors
 
diff --git a/src/test/ui/argument-suggestions/issue-100478.rs b/src/test/ui/argument-suggestions/issue-100478.rs
new file mode 100644
index 000000000000..6bef6ad10386
--- /dev/null
+++ b/src/test/ui/argument-suggestions/issue-100478.rs
@@ -0,0 +1,52 @@
+use std::sync::Arc;
+macro_rules! GenT {
+    ($name:tt) => {
+        #[derive(Default, Debug)]
+        struct $name {
+            #[allow(unused)]
+            val: i32,
+        }
+
+        impl $name {
+            #[allow(unused)]
+            fn new(val: i32) -> Self {
+                $name { val }
+            }
+        }
+    };
+}
+
+GenT!(T1);
+GenT!(T2);
+GenT!(T3);
+GenT!(T4);
+GenT!(T5);
+GenT!(T6);
+GenT!(T7);
+GenT!(T8);
+
+#[allow(unused)]
+fn foo(p1: T1, p2: Arc<T2>, p3: T3, p4: Arc<T4>, p5: T5, p6: T6, p7: T7, p8: Arc<T8>) {}
+fn three_diff(_a: T1, _b: T2, _c: T3) {}
+fn four_shuffle(_a: T1, _b: T2, _c: T3, _d: T4) {}
+
+fn main() {
+    three_diff(T2::new(0)); //~ ERROR this function takes
+    four_shuffle(T3::default(), T4::default(), T1::default(), T2::default()); //~ ERROR 35:5: 35:17: arguments to this function are incorrect [E0308]
+    four_shuffle(T3::default(), T2::default(), T1::default(), T3::default()); //~ ERROR 36:5: 36:17: arguments to this function are incorrect [E0308]
+
+    let p1 = T1::new(0);
+    let p2 = Arc::new(T2::new(0));
+    let p3 = T3::new(0);
+    let p4 = Arc::new(T4::new(1));
+    let p5 = T5::new(0);
+    let p6 = T6::new(0);
+    let p7 = T7::new(0);
+    let p8 = Arc::default();
+
+    foo(
+        //~^ 47:5: 47:8: this function takes 8 arguments but 7 arguments were supplied [E0061]
+        p1, //p2,
+        p3, p4, p5, p6, p7, p8,
+    );
+}
diff --git a/src/test/ui/argument-suggestions/issue-100478.stderr b/src/test/ui/argument-suggestions/issue-100478.stderr
new file mode 100644
index 000000000000..df02a312cf11
--- /dev/null
+++ b/src/test/ui/argument-suggestions/issue-100478.stderr
@@ -0,0 +1,81 @@
+error[E0061]: this function takes 3 arguments but 1 argument was supplied
+  --> $DIR/issue-100478.rs:34:5
+   |
+LL |     three_diff(T2::new(0));
+   |     ^^^^^^^^^^------------
+   |               ||
+   |               |an argument of type `T1` is missing
+   |               an argument of type `T3` is missing
+   |
+note: function defined here
+  --> $DIR/issue-100478.rs:30:4
+   |
+LL | fn three_diff(_a: T1, _b: T2, _c: T3) {}
+   |    ^^^^^^^^^^ ------  ------  ------
+help: provide the arguments
+   |
+LL |     three_diff(/* T1 */, T2::new(0), /* T3 */);
+   |               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0308]: arguments to this function are incorrect
+  --> $DIR/issue-100478.rs:35:5
+   |
+LL |     four_shuffle(T3::default(), T4::default(), T1::default(), T2::default());
+   |     ^^^^^^^^^^^^ -------------  -------------  -------------  ------------- expected `T4`, found `T2`
+   |                  |              |              |
+   |                  |              |              expected `T3`, found `T1`
+   |                  |              expected `T2`, found `T4`
+   |                  expected `T1`, found `T3`
+   |
+note: function defined here
+  --> $DIR/issue-100478.rs:31:4
+   |
+LL | fn four_shuffle(_a: T1, _b: T2, _c: T3, _d: T4) {}
+   |    ^^^^^^^^^^^^ ------  ------  ------  ------
+help: did you mean
+   |
+LL |     four_shuffle(T1::default(), T2::default(), T3::default(), T4::default());
+   |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0308]: arguments to this function are incorrect
+  --> $DIR/issue-100478.rs:36:5
+   |
+LL |     four_shuffle(T3::default(), T2::default(), T1::default(), T3::default());
+   |     ^^^^^^^^^^^^ -------------                 -------------  ------------- expected struct `T4`, found struct `T3`
+   |                  |                             |
+   |                  |                             expected `T3`, found `T1`
+   |                  expected `T1`, found `T3`
+   |
+note: function defined here
+  --> $DIR/issue-100478.rs:31:4
+   |
+LL | fn four_shuffle(_a: T1, _b: T2, _c: T3, _d: T4) {}
+   |    ^^^^^^^^^^^^ ------  ------  ------  ------
+help: swap these arguments
+   |
+LL |     four_shuffle(T1::default(), T2::default(), T3::default(), /* T4 */);
+   |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0061]: this function takes 8 arguments but 7 arguments were supplied
+  --> $DIR/issue-100478.rs:47:5
+   |
+LL |     foo(
+   |     ^^^
+...
+LL |         p3, p4, p5, p6, p7, p8,
+   |         -- an argument of type `Arc<T2>` is missing
+   |
+note: function defined here
+  --> $DIR/issue-100478.rs:29:4
+   |
+LL | fn foo(p1: T1, p2: Arc<T2>, p3: T3, p4: Arc<T4>, p5: T5, p6: T6, p7: T7, p8: Arc<T8>) {}
+   |    ^^^ ------  -----------  ------  -----------  ------  ------  ------  -----------
+help: provide the argument
+   |
+LL |     foo(p1, /* Arc<T2> */, p3, p4, p5, p6, p7, p8);
+   |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0061, E0308.
+For more information about an error, try `rustc --explain E0061`.
diff --git a/src/test/ui/argument-suggestions/issue-101097.rs b/src/test/ui/argument-suggestions/issue-101097.rs
new file mode 100644
index 000000000000..7994d3cd9959
--- /dev/null
+++ b/src/test/ui/argument-suggestions/issue-101097.rs
@@ -0,0 +1,21 @@
+struct A;
+struct B;
+struct C;
+struct D;
+
+fn f(
+    a1: A,
+    a2: A,
+    b1: B,
+    b2: B,
+    c1: C,
+    c2: C,
+) {}
+
+fn main() {
+    f(C, A, A, A, B, B, C); //~ ERROR this function takes 6 arguments but 7 arguments were supplied [E0061]
+    f(C, C, A, A, B, B);  //~ ERROR arguments to this function are incorrect [E0308]
+    f(A, A, D, D, B, B);  //~ arguments to this function are incorrect [E0308]
+    f(C, C, B, B, A, A);  //~ arguments to this function are incorrect [E0308]
+    f(C, C, A, B, A, A);  //~ arguments to this function are incorrect [E0308]
+}
diff --git a/src/test/ui/argument-suggestions/issue-101097.stderr b/src/test/ui/argument-suggestions/issue-101097.stderr
new file mode 100644
index 000000000000..096f8c226f2a
--- /dev/null
+++ b/src/test/ui/argument-suggestions/issue-101097.stderr
@@ -0,0 +1,160 @@
+error[E0061]: this function takes 6 arguments but 7 arguments were supplied
+  --> $DIR/issue-101097.rs:16:5
+   |
+LL |     f(C, A, A, A, B, B, C);
+   |     ^ -     -  -  - expected `C`, found `B`
+   |       |     |  |
+   |       |     |  argument of type `A` unexpected
+   |       |     expected `B`, found `A`
+   |       expected `A`, found `C`
+   |
+note: function defined here
+  --> $DIR/issue-101097.rs:6:4
+   |
+LL | fn f(
+   |    ^
+LL |     a1: A,
+   |     -----
+LL |     a2: A,
+   |     -----
+LL |     b1: B,
+   |     -----
+LL |     b2: B,
+   |     -----
+LL |     c1: C,
+   |     -----
+LL |     c2: C,
+   |     -----
+help: did you mean
+   |
+LL |     f(A, A, B, B, C, C);
+   |      ~~~~~~~~~~~~~~~~~~
+
+error[E0308]: arguments to this function are incorrect
+  --> $DIR/issue-101097.rs:17:5
+   |
+LL |     f(C, C, A, A, B, B);
+   |     ^
+   |
+note: function defined here
+  --> $DIR/issue-101097.rs:6:4
+   |
+LL | fn f(
+   |    ^
+LL |     a1: A,
+   |     -----
+LL |     a2: A,
+   |     -----
+LL |     b1: B,
+   |     -----
+LL |     b2: B,
+   |     -----
+LL |     c1: C,
+   |     -----
+LL |     c2: C,
+   |     -----
+help: did you mean
+   |
+LL |     f(A, A, B, B, C, C);
+   |      ~~~~~~~~~~~~~~~~~~
+
+error[E0308]: arguments to this function are incorrect
+  --> $DIR/issue-101097.rs:18:5
+   |
+LL |     f(A, A, D, D, B, B);
+   |     ^       -  -  ---- two arguments of type `C` and `C` are missing
+   |             |  |
+   |             |  argument of type `D` unexpected
+   |             argument of type `D` unexpected
+   |
+note: function defined here
+  --> $DIR/issue-101097.rs:6:4
+   |
+LL | fn f(
+   |    ^
+LL |     a1: A,
+   |     -----
+LL |     a2: A,
+   |     -----
+LL |     b1: B,
+   |     -----
+LL |     b2: B,
+   |     -----
+LL |     c1: C,
+   |     -----
+LL |     c2: C,
+   |     -----
+help: did you mean
+   |
+LL |     f(A, A, B, B, /* C */, /* C */);
+   |      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error[E0308]: arguments to this function are incorrect
+  --> $DIR/issue-101097.rs:19:5
+   |
+LL |     f(C, C, B, B, A, A);
+   |     ^ -  -        -  - expected `C`, found `A`
+   |       |  |        |
+   |       |  |        expected `C`, found `A`
+   |       |  expected `A`, found `C`
+   |       expected `A`, found `C`
+   |
+note: function defined here
+  --> $DIR/issue-101097.rs:6:4
+   |
+LL | fn f(
+   |    ^
+LL |     a1: A,
+   |     -----
+LL |     a2: A,
+   |     -----
+LL |     b1: B,
+   |     -----
+LL |     b2: B,
+   |     -----
+LL |     c1: C,
+   |     -----
+LL |     c2: C,
+   |     -----
+help: did you mean
+   |
+LL |     f(A, A, B, B, C, C);
+   |      ~~~~~~~~~~~~~~~~~~
+
+error[E0308]: arguments to this function are incorrect
+  --> $DIR/issue-101097.rs:20:5
+   |
+LL |     f(C, C, A, B, A, A);
+   |     ^ -  -  -     -  - expected `C`, found `A`
+   |       |  |  |     |
+   |       |  |  |     expected `C`, found `A`
+   |       |  |  expected struct `B`, found struct `A`
+   |       |  expected `A`, found `C`
+   |       expected `A`, found `C`
+   |
+note: function defined here
+  --> $DIR/issue-101097.rs:6:4
+   |
+LL | fn f(
+   |    ^
+LL |     a1: A,
+   |     -----
+LL |     a2: A,
+   |     -----
+LL |     b1: B,
+   |     -----
+LL |     b2: B,
+   |     -----
+LL |     c1: C,
+   |     -----
+LL |     c2: C,
+   |     -----
+help: did you mean
+   |
+LL |     f(A, A, /* B */, B, C, C);
+   |      ~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0061, E0308.
+For more information about an error, try `rustc --explain E0061`.
diff --git a/src/test/ui/argument-suggestions/issue-96638.stderr b/src/test/ui/argument-suggestions/issue-96638.stderr
index 804cb1aa3221..4d18b97c98be 100644
--- a/src/test/ui/argument-suggestions/issue-96638.stderr
+++ b/src/test/ui/argument-suggestions/issue-96638.stderr
@@ -14,7 +14,7 @@ LL | fn f(_: usize, _: &usize, _: usize) {}
 help: provide the argument
    |
 LL |     f(/* usize */, &x, /* usize */);
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/issue-97197.stderr b/src/test/ui/argument-suggestions/issue-97197.stderr
index ac54adc5eeb9..de221ba1fe18 100644
--- a/src/test/ui/argument-suggestions/issue-97197.stderr
+++ b/src/test/ui/argument-suggestions/issue-97197.stderr
@@ -12,7 +12,7 @@ LL | pub fn g(a1: (), a2: bool, a3: bool, a4: bool, a5: bool, a6: ()) -> () {}
 help: provide the arguments
    |
 LL |     g((), /* bool */, /* bool */, /* bool */, /* bool */, ());
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/issue-97484.stderr b/src/test/ui/argument-suggestions/issue-97484.stderr
index b5dedf0f4fa0..caa50f14b43e 100644
--- a/src/test/ui/argument-suggestions/issue-97484.stderr
+++ b/src/test/ui/argument-suggestions/issue-97484.stderr
@@ -20,7 +20,7 @@ LL |     foo(&&A, B, C, D, &E, F, G);
 help: remove the extra arguments
    |
 LL |     foo(&&A, D, /* &E */, G);
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~
+   |        ~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/issue-98894.stderr b/src/test/ui/argument-suggestions/issue-98894.stderr
index 0c8b94901e16..f64a83ab7106 100644
--- a/src/test/ui/argument-suggestions/issue-98894.stderr
+++ b/src/test/ui/argument-suggestions/issue-98894.stderr
@@ -12,7 +12,7 @@ LL |     (|_, ()| ())(if true {} else {return;});
 help: provide the argument
    |
 LL |     (|_, ()| ())(if true {} else {return;}, ());
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/issue-98897.stderr b/src/test/ui/argument-suggestions/issue-98897.stderr
index 8f0d98d09e89..f2c47d353efa 100644
--- a/src/test/ui/argument-suggestions/issue-98897.stderr
+++ b/src/test/ui/argument-suggestions/issue-98897.stderr
@@ -12,7 +12,7 @@ LL |     (|_, ()| ())([return, ()]);
 help: provide the argument
    |
 LL |     (|_, ()| ())([return, ()], ());
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                 ~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/issue-99482.stderr b/src/test/ui/argument-suggestions/issue-99482.stderr
index bc005e82a2c4..bcf36e37cdcc 100644
--- a/src/test/ui/argument-suggestions/issue-99482.stderr
+++ b/src/test/ui/argument-suggestions/issue-99482.stderr
@@ -12,7 +12,7 @@ LL |     let f = |_: (), f: fn()| f;
 help: provide the argument
    |
 LL |     let _f = f((), main);
-   |              ~~~~~~~~~~~
+   |               ~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/argument-suggestions/missing_arguments.stderr b/src/test/ui/argument-suggestions/missing_arguments.stderr
index 2509d22d7ff8..ba9ece040bec 100644
--- a/src/test/ui/argument-suggestions/missing_arguments.stderr
+++ b/src/test/ui/argument-suggestions/missing_arguments.stderr
@@ -12,7 +12,7 @@ LL | fn one_arg(_a: i32) {}
 help: provide the argument
    |
 LL |   one_arg(/* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 0 arguments were supplied
   --> $DIR/missing_arguments.rs:14:3
@@ -28,7 +28,7 @@ LL | fn two_same(_a: i32, _b: i32) {}
 help: provide the arguments
    |
 LL |   two_same(/* i32 */, /* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:15:3
@@ -44,7 +44,7 @@ LL | fn two_same(_a: i32, _b: i32) {}
 help: provide the argument
    |
 LL |   two_same(1, /* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 0 arguments were supplied
   --> $DIR/missing_arguments.rs:16:3
@@ -60,7 +60,7 @@ LL | fn two_diff(_a: i32, _b: f32) {}
 help: provide the arguments
    |
 LL |   two_diff(/* i32 */, /* f32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:17:3
@@ -76,7 +76,7 @@ LL | fn two_diff(_a: i32, _b: f32) {}
 help: provide the argument
    |
 LL |   two_diff(1, /* f32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:18:3
@@ -92,7 +92,7 @@ LL | fn two_diff(_a: i32, _b: f32) {}
 help: provide the argument
    |
 LL |   two_diff(/* i32 */, 1.0);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 0 arguments were supplied
   --> $DIR/missing_arguments.rs:21:3
@@ -108,7 +108,7 @@ LL | fn three_same(_a: i32, _b: i32, _c: i32) {}
 help: provide the arguments
    |
 LL |   three_same(/* i32 */, /* i32 */, /* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:22:3
@@ -124,7 +124,7 @@ LL | fn three_same(_a: i32, _b: i32, _c: i32) {}
 help: provide the arguments
    |
 LL |   three_same(1, /* i32 */, /* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 2 arguments were supplied
   --> $DIR/missing_arguments.rs:23:3
@@ -140,7 +140,7 @@ LL | fn three_same(_a: i32, _b: i32, _c: i32) {}
 help: provide the argument
    |
 LL |   three_same(1, 1, /* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 2 arguments were supplied
   --> $DIR/missing_arguments.rs:26:3
@@ -156,7 +156,7 @@ LL | fn three_diff(_a: i32, _b: f32, _c: &str) {}
 help: provide the argument
    |
 LL |   three_diff(/* i32 */, 1.0, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 2 arguments were supplied
   --> $DIR/missing_arguments.rs:27:3
@@ -172,7 +172,7 @@ LL | fn three_diff(_a: i32, _b: f32, _c: &str) {}
 help: provide the argument
    |
 LL |   three_diff(1, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 2 arguments were supplied
   --> $DIR/missing_arguments.rs:28:3
@@ -188,7 +188,7 @@ LL | fn three_diff(_a: i32, _b: f32, _c: &str) {}
 help: provide the argument
    |
 LL |   three_diff(1, 1.0, /* &str */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:29:3
@@ -204,7 +204,7 @@ LL | fn three_diff(_a: i32, _b: f32, _c: &str) {}
 help: provide the arguments
    |
 LL |   three_diff(/* i32 */, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:30:3
@@ -223,7 +223,7 @@ LL | fn three_diff(_a: i32, _b: f32, _c: &str) {}
 help: provide the arguments
    |
 LL |   three_diff(/* i32 */, 1.0, /* &str */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 1 argument was supplied
   --> $DIR/missing_arguments.rs:31:3
@@ -239,7 +239,7 @@ LL | fn three_diff(_a: i32, _b: f32, _c: &str) {}
 help: provide the arguments
    |
 LL |   three_diff(1, /* f32 */, /* &str */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 4 arguments but 0 arguments were supplied
   --> $DIR/missing_arguments.rs:34:3
@@ -255,7 +255,7 @@ LL | fn four_repeated(_a: i32, _b: f32, _c: f32, _d: &str) {}
 help: provide the arguments
    |
 LL |   four_repeated(/* i32 */, /* f32 */, /* f32 */, /* &str */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 4 arguments but 2 arguments were supplied
   --> $DIR/missing_arguments.rs:35:3
@@ -271,7 +271,7 @@ LL | fn four_repeated(_a: i32, _b: f32, _c: f32, _d: &str) {}
 help: provide the arguments
    |
 LL |   four_repeated(1, /* f32 */, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 5 arguments but 0 arguments were supplied
   --> $DIR/missing_arguments.rs:38:3
@@ -287,7 +287,7 @@ LL | fn complex(_a: i32, _b: f32, _c: i32, _d: f32, _e: &str) {}
 help: provide the arguments
    |
 LL |   complex(/* i32 */, /* f32 */, /* i32 */, /* f32 */, /* &str */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 5 arguments but 2 arguments were supplied
   --> $DIR/missing_arguments.rs:39:3
@@ -303,7 +303,7 @@ LL | fn complex(_a: i32, _b: f32, _c: i32, _d: f32, _e: &str) {}
 help: provide the arguments
    |
 LL |   complex(1, /* f32 */, /* i32 */, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 19 previous errors
 
diff --git a/src/test/ui/argument-suggestions/mixed_cases.stderr b/src/test/ui/argument-suggestions/mixed_cases.stderr
index a52a30d7884f..8c525db1ac66 100644
--- a/src/test/ui/argument-suggestions/mixed_cases.stderr
+++ b/src/test/ui/argument-suggestions/mixed_cases.stderr
@@ -14,7 +14,7 @@ LL | fn two_args(_a: i32, _b: f32) {}
 help: remove the extra argument
    |
 LL |   two_args(1, /* f32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 4 arguments were supplied
   --> $DIR/mixed_cases.rs:11:3
@@ -33,7 +33,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: did you mean
    |
 LL |   three_args(1, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 2 arguments were supplied
   --> $DIR/mixed_cases.rs:14:3
@@ -52,7 +52,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: provide the argument
    |
 LL |   three_args(1, /* f32 */, /* &str */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/mixed_cases.rs:17:3
@@ -70,7 +70,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: did you mean
    |
 LL |   three_args(1, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/mixed_cases.rs:20:3
@@ -89,7 +89,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: swap these arguments
    |
 LL |   three_args(1, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 3 arguments but 2 arguments were supplied
   --> $DIR/mixed_cases.rs:23:3
@@ -109,7 +109,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: did you mean
    |
 LL |   three_args(1, /* f32 */, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/argument-suggestions/permuted_arguments.stderr b/src/test/ui/argument-suggestions/permuted_arguments.stderr
index f16d22860d80..655807a7f382 100644
--- a/src/test/ui/argument-suggestions/permuted_arguments.stderr
+++ b/src/test/ui/argument-suggestions/permuted_arguments.stderr
@@ -15,7 +15,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: reorder these arguments
    |
 LL |   three_args(1, 1.0, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/permuted_arguments.rs:12:3
@@ -36,7 +36,7 @@ LL | fn many_args(_a: i32, _b: f32, _c: &str, _d: X, _e: Y) {}
 help: reorder these arguments
    |
 LL |   many_args(1, 1.0, "", X {}, Y {});
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/argument-suggestions/swapped_arguments.stderr b/src/test/ui/argument-suggestions/swapped_arguments.stderr
index a90792d0c534..dabf5e952b26 100644
--- a/src/test/ui/argument-suggestions/swapped_arguments.stderr
+++ b/src/test/ui/argument-suggestions/swapped_arguments.stderr
@@ -14,7 +14,7 @@ LL | fn two_args(_a: i32, _b: f32) {}
 help: swap these arguments
    |
 LL |   two_args(1, 1.0);
-   |   ~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/swapped_arguments.rs:9:3
@@ -32,7 +32,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: swap these arguments
    |
 LL |   three_args(1, 1.0, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/swapped_arguments.rs:10:3
@@ -50,7 +50,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: swap these arguments
    |
 LL |   three_args(1, 1.0, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/swapped_arguments.rs:11:3
@@ -68,7 +68,7 @@ LL | fn three_args(_a: i32, _b: f32, _c: &str) {}
 help: swap these arguments
    |
 LL |   three_args(1, 1.0, "");
-   |   ~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~
 
 error[E0308]: arguments to this function are incorrect
   --> $DIR/swapped_arguments.rs:13:3
@@ -88,7 +88,7 @@ LL | fn four_args(_a: i32, _b: f32, _c: &str, _d: X) {}
 help: did you mean
    |
 LL |   four_args(1, 1.0, "", X {});
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/array-slice-vec/suggest-array-length.fixed b/src/test/ui/array-slice-vec/suggest-array-length.fixed
index bae3ab74af67..867c18a7d5e6 100644
--- a/src/test/ui/array-slice-vec/suggest-array-length.fixed
+++ b/src/test/ui/array-slice-vec/suggest-array-length.fixed
@@ -5,10 +5,22 @@ fn main() {
     const Foo: [i32; 3] = [1, 2, 3];
     //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
     //~| ERROR using `_` for array lengths is unstable
+    const REF_FOO: &[u8; 1] = &[1];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
     let foo: [i32; 3] = [1, 2, 3];
     //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
     //~| ERROR using `_` for array lengths is unstable
     let bar: [i32; 3] = [0; 3];
     //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
     //~| ERROR using `_` for array lengths is unstable
+    let ref_foo: &[i32; 3] = &[1, 2, 3];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
+    let ref_bar: &[i32; 3] = &[0; 3];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
+    let multiple_ref_foo: &&[i32; 3] = &&[1, 2, 3];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
 }
diff --git a/src/test/ui/array-slice-vec/suggest-array-length.rs b/src/test/ui/array-slice-vec/suggest-array-length.rs
index b0867f4e3967..f66b3d4a8999 100644
--- a/src/test/ui/array-slice-vec/suggest-array-length.rs
+++ b/src/test/ui/array-slice-vec/suggest-array-length.rs
@@ -5,10 +5,22 @@ fn main() {
     const Foo: [i32; _] = [1, 2, 3];
     //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
     //~| ERROR using `_` for array lengths is unstable
+    const REF_FOO: &[u8; _] = &[1];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
     let foo: [i32; _] = [1, 2, 3];
     //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
     //~| ERROR using `_` for array lengths is unstable
     let bar: [i32; _] = [0; 3];
     //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
     //~| ERROR using `_` for array lengths is unstable
+    let ref_foo: &[i32; _] = &[1, 2, 3];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
+    let ref_bar: &[i32; _] = &[0; 3];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
+    let multiple_ref_foo: &&[i32; _] = &&[1, 2, 3];
+    //~^ ERROR in expressions, `_` can only be used on the left-hand side of an assignment
+    //~| ERROR using `_` for array lengths is unstable
 }
diff --git a/src/test/ui/array-slice-vec/suggest-array-length.stderr b/src/test/ui/array-slice-vec/suggest-array-length.stderr
index 9000f7160285..16c90a04784d 100644
--- a/src/test/ui/array-slice-vec/suggest-array-length.stderr
+++ b/src/test/ui/array-slice-vec/suggest-array-length.stderr
@@ -1,21 +1,45 @@
 error: in expressions, `_` can only be used on the left-hand side of an assignment
-  --> $DIR/suggest-array-length.rs:8:20
+  --> $DIR/suggest-array-length.rs:11:20
    |
 LL |     let foo: [i32; _] = [1, 2, 3];
    |                    ^ `_` not allowed here
 
 error: in expressions, `_` can only be used on the left-hand side of an assignment
-  --> $DIR/suggest-array-length.rs:11:20
+  --> $DIR/suggest-array-length.rs:14:20
    |
 LL |     let bar: [i32; _] = [0; 3];
    |                    ^ `_` not allowed here
 
+error: in expressions, `_` can only be used on the left-hand side of an assignment
+  --> $DIR/suggest-array-length.rs:17:25
+   |
+LL |     let ref_foo: &[i32; _] = &[1, 2, 3];
+   |                         ^ `_` not allowed here
+
+error: in expressions, `_` can only be used on the left-hand side of an assignment
+  --> $DIR/suggest-array-length.rs:20:25
+   |
+LL |     let ref_bar: &[i32; _] = &[0; 3];
+   |                         ^ `_` not allowed here
+
+error: in expressions, `_` can only be used on the left-hand side of an assignment
+  --> $DIR/suggest-array-length.rs:23:35
+   |
+LL |     let multiple_ref_foo: &&[i32; _] = &&[1, 2, 3];
+   |                                   ^ `_` not allowed here
+
 error: in expressions, `_` can only be used on the left-hand side of an assignment
   --> $DIR/suggest-array-length.rs:5:22
    |
 LL |     const Foo: [i32; _] = [1, 2, 3];
    |                      ^ `_` not allowed here
 
+error: in expressions, `_` can only be used on the left-hand side of an assignment
+  --> $DIR/suggest-array-length.rs:8:26
+   |
+LL |     const REF_FOO: &[u8; _] = &[1];
+   |                          ^ `_` not allowed here
+
 error[E0658]: using `_` for array lengths is unstable
   --> $DIR/suggest-array-length.rs:5:22
    |
@@ -26,7 +50,16 @@ LL |     const Foo: [i32; _] = [1, 2, 3];
    = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 
 error[E0658]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:8:20
+  --> $DIR/suggest-array-length.rs:8:26
+   |
+LL |     const REF_FOO: &[u8; _] = &[1];
+   |                          ^ help: consider specifying the array length: `1`
+   |
+   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
+   = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+
+error[E0658]: using `_` for array lengths is unstable
+  --> $DIR/suggest-array-length.rs:11:20
    |
 LL |     let foo: [i32; _] = [1, 2, 3];
    |                    ^ help: consider specifying the array length: `3`
@@ -35,7 +68,7 @@ LL |     let foo: [i32; _] = [1, 2, 3];
    = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 
 error[E0658]: using `_` for array lengths is unstable
-  --> $DIR/suggest-array-length.rs:11:20
+  --> $DIR/suggest-array-length.rs:14:20
    |
 LL |     let bar: [i32; _] = [0; 3];
    |                    ^ help: consider specifying the array length: `3`
@@ -43,6 +76,33 @@ LL |     let bar: [i32; _] = [0; 3];
    = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
    = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 
-error: aborting due to 6 previous errors
+error[E0658]: using `_` for array lengths is unstable
+  --> $DIR/suggest-array-length.rs:17:25
+   |
+LL |     let ref_foo: &[i32; _] = &[1, 2, 3];
+   |                         ^ help: consider specifying the array length: `3`
+   |
+   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
+   = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+
+error[E0658]: using `_` for array lengths is unstable
+  --> $DIR/suggest-array-length.rs:20:25
+   |
+LL |     let ref_bar: &[i32; _] = &[0; 3];
+   |                         ^ help: consider specifying the array length: `3`
+   |
+   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
+   = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+
+error[E0658]: using `_` for array lengths is unstable
+  --> $DIR/suggest-array-length.rs:23:35
+   |
+LL |     let multiple_ref_foo: &&[i32; _] = &&[1, 2, 3];
+   |                                   ^ help: consider specifying the array length: `3`
+   |
+   = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
+   = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
+
+error: aborting due to 14 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/asm/aarch64/type-check-2-2.stderr b/src/test/ui/asm/aarch64/type-check-2-2.stderr
index b2a695529f94..eef16a165a87 100644
--- a/src/test/ui/asm/aarch64/type-check-2-2.stderr
+++ b/src/test/ui/asm/aarch64/type-check-2-2.stderr
@@ -5,6 +5,11 @@ LL |         let x: u64;
    |             - binding declared here but left uninitialized
 LL |         asm!("{}", in(reg) x);
    |                            ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let x: u64 = 0;
+   |                    +++
 
 error[E0381]: used binding `y` isn't initialized
   --> $DIR/type-check-2-2.rs:22:9
@@ -13,6 +18,11 @@ LL |         let mut y: u64;
    |             ----- binding declared here but left uninitialized
 LL |         asm!("{}", inout(reg) y);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ `y` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let mut y: u64 = 0;
+   |                        +++
 
 error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
   --> $DIR/type-check-2-2.rs:30:29
diff --git a/src/test/ui/asm/aarch64/type-check-3.stderr b/src/test/ui/asm/aarch64/type-check-3.stderr
index b320abdc01b7..49292982eec7 100644
--- a/src/test/ui/asm/aarch64/type-check-3.stderr
+++ b/src/test/ui/asm/aarch64/type-check-3.stderr
@@ -5,8 +5,8 @@ LL |         asm!("{}", in(reg) 0u8);
    |               ^^           --- for this argument
    |
    = note: `#[warn(asm_sub_register)]` on by default
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:50:15
@@ -14,8 +14,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(reg) 0u16);
    |               ^^           ---- for this argument
    |
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:52:15
@@ -23,8 +23,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(reg) 0i32);
    |               ^^           ---- for this argument
    |
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:54:15
@@ -32,8 +32,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(reg) 0f32);
    |               ^^           ---- for this argument
    |
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:57:15
@@ -41,8 +41,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(vreg) 0i16);
    |               ^^            ---- for this argument
    |
-   = help: use the `h` modifier to have the register formatted as `h0`
-   = help: or use the `v` modifier to keep the default formatting of `v0`
+   = help: use `{0:h}` to have the register formatted as `h0`
+   = help: or use `{0:v}` to keep the default formatting of `v0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:59:15
@@ -50,8 +50,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(vreg) 0f32);
    |               ^^            ---- for this argument
    |
-   = help: use the `s` modifier to have the register formatted as `s0`
-   = help: or use the `v` modifier to keep the default formatting of `v0`
+   = help: use `{0:s}` to have the register formatted as `s0`
+   = help: or use `{0:v}` to keep the default formatting of `v0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:61:15
@@ -59,8 +59,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(vreg) 0f64);
    |               ^^            ---- for this argument
    |
-   = help: use the `d` modifier to have the register formatted as `d0`
-   = help: or use the `v` modifier to keep the default formatting of `v0`
+   = help: use `{0:d}` to have the register formatted as `d0`
+   = help: or use `{0:v}` to keep the default formatting of `v0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:63:15
@@ -68,8 +68,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(vreg_low16) 0f64);
    |               ^^                  ---- for this argument
    |
-   = help: use the `d` modifier to have the register formatted as `d0`
-   = help: or use the `v` modifier to keep the default formatting of `v0`
+   = help: use `{0:d}` to have the register formatted as `d0`
+   = help: or use `{0:v}` to keep the default formatting of `v0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:66:15
@@ -77,8 +77,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{0} {0}", in(reg) 0i16);
    |               ^^^ ^^^           ---- for this argument
    |
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:68:15
@@ -86,8 +86,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{0} {0:x}", in(reg) 0i16);
    |               ^^^                 ---- for this argument
    |
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 error: type `i128` cannot be used with this register class
   --> $DIR/type-check-3.rs:73:28
diff --git a/src/test/ui/asm/bad-template.aarch64_mirunsafeck.stderr b/src/test/ui/asm/bad-template.aarch64_mirunsafeck.stderr
index 7ef93e15f5ba..5dac693cc274 100644
--- a/src/test/ui/asm/bad-template.aarch64_mirunsafeck.stderr
+++ b/src/test/ui/asm/bad-template.aarch64_mirunsafeck.stderr
@@ -190,8 +190,8 @@ LL |         asm!("{:foo}", in(reg) foo);
    |               ^^^^^^           --- for this argument
    |
    = note: `#[warn(asm_sub_register)]` on by default
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 error: aborting due to 21 previous errors; 1 warning emitted
 
diff --git a/src/test/ui/asm/bad-template.aarch64_thirunsafeck.stderr b/src/test/ui/asm/bad-template.aarch64_thirunsafeck.stderr
index 7ef93e15f5ba..5dac693cc274 100644
--- a/src/test/ui/asm/bad-template.aarch64_thirunsafeck.stderr
+++ b/src/test/ui/asm/bad-template.aarch64_thirunsafeck.stderr
@@ -190,8 +190,8 @@ LL |         asm!("{:foo}", in(reg) foo);
    |               ^^^^^^           --- for this argument
    |
    = note: `#[warn(asm_sub_register)]` on by default
-   = help: use the `w` modifier to have the register formatted as `w0`
-   = help: or use the `x` modifier to keep the default formatting of `x0`
+   = help: use `{0:w}` to have the register formatted as `w0`
+   = help: or use `{0:x}` to keep the default formatting of `x0`
 
 error: aborting due to 21 previous errors; 1 warning emitted
 
diff --git a/src/test/ui/asm/bad-template.x86_64_mirunsafeck.stderr b/src/test/ui/asm/bad-template.x86_64_mirunsafeck.stderr
index 250bc3be42eb..b29b74bac80b 100644
--- a/src/test/ui/asm/bad-template.x86_64_mirunsafeck.stderr
+++ b/src/test/ui/asm/bad-template.x86_64_mirunsafeck.stderr
@@ -190,8 +190,8 @@ LL |         asm!("{:foo}", in(reg) foo);
    |               ^^^^^^           --- for this argument
    |
    = note: `#[warn(asm_sub_register)]` on by default
-   = help: use the `e` modifier to have the register formatted as `eax`
-   = help: or use the `r` modifier to keep the default formatting of `rax`
+   = help: use `{0:e}` to have the register formatted as `eax`
+   = help: or use `{0:r}` to keep the default formatting of `rax`
 
 error: aborting due to 21 previous errors; 1 warning emitted
 
diff --git a/src/test/ui/asm/bad-template.x86_64_thirunsafeck.stderr b/src/test/ui/asm/bad-template.x86_64_thirunsafeck.stderr
index 250bc3be42eb..b29b74bac80b 100644
--- a/src/test/ui/asm/bad-template.x86_64_thirunsafeck.stderr
+++ b/src/test/ui/asm/bad-template.x86_64_thirunsafeck.stderr
@@ -190,8 +190,8 @@ LL |         asm!("{:foo}", in(reg) foo);
    |               ^^^^^^           --- for this argument
    |
    = note: `#[warn(asm_sub_register)]` on by default
-   = help: use the `e` modifier to have the register formatted as `eax`
-   = help: or use the `r` modifier to keep the default formatting of `rax`
+   = help: use `{0:e}` to have the register formatted as `eax`
+   = help: or use `{0:r}` to keep the default formatting of `rax`
 
 error: aborting due to 21 previous errors; 1 warning emitted
 
diff --git a/src/test/ui/asm/unpretty-expanded.rs b/src/test/ui/asm/unpretty-expanded.rs
new file mode 100644
index 000000000000..6128f49b89a3
--- /dev/null
+++ b/src/test/ui/asm/unpretty-expanded.rs
@@ -0,0 +1,3 @@
+// check-pass
+// compile-flags: -Zunpretty=expanded
+core::arch::global_asm!("x: .byte 42");
diff --git a/src/test/ui/asm/unpretty-expanded.stdout b/src/test/ui/asm/unpretty-expanded.stdout
new file mode 100644
index 000000000000..15b60d1559c6
--- /dev/null
+++ b/src/test/ui/asm/unpretty-expanded.stdout
@@ -0,0 +1,9 @@
+#![feature(prelude_import)]
+#![no_std]
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+// check-pass
+// compile-flags: -Zunpretty=expanded
+global_asm! ("x: .byte 42");
diff --git a/src/test/ui/asm/x86_64/may_unwind.rs b/src/test/ui/asm/x86_64/may_unwind.rs
index badc4fec8224..2f5d1a360246 100644
--- a/src/test/ui/asm/x86_64/may_unwind.rs
+++ b/src/test/ui/asm/x86_64/may_unwind.rs
@@ -1,6 +1,7 @@
 // only-x86_64
 // run-pass
 // needs-asm-support
+// needs-unwind
 
 #![feature(asm_sym, asm_unwind)]
 
diff --git a/src/test/ui/asm/x86_64/type-check-3.stderr b/src/test/ui/asm/x86_64/type-check-3.stderr
index b38ea8cc4d8e..366038fea234 100644
--- a/src/test/ui/asm/x86_64/type-check-3.stderr
+++ b/src/test/ui/asm/x86_64/type-check-3.stderr
@@ -45,8 +45,8 @@ LL |         asm!("{0} {0}", in(reg) 0i16);
    |               ^^^ ^^^           ---- for this argument
    |
    = note: `#[warn(asm_sub_register)]` on by default
-   = help: use the `x` modifier to have the register formatted as `ax`
-   = help: or use the `r` modifier to keep the default formatting of `rax`
+   = help: use `{0:x}` to have the register formatted as `ax`
+   = help: or use `{0:r}` to keep the default formatting of `rax`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:36:15
@@ -54,8 +54,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{0} {0:x}", in(reg) 0i16);
    |               ^^^                 ---- for this argument
    |
-   = help: use the `x` modifier to have the register formatted as `ax`
-   = help: or use the `r` modifier to keep the default formatting of `rax`
+   = help: use `{0:x}` to have the register formatted as `ax`
+   = help: or use `{0:r}` to keep the default formatting of `rax`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:38:15
@@ -63,8 +63,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(reg) 0i32);
    |               ^^           ---- for this argument
    |
-   = help: use the `e` modifier to have the register formatted as `eax`
-   = help: or use the `r` modifier to keep the default formatting of `rax`
+   = help: use `{0:e}` to have the register formatted as `eax`
+   = help: or use `{0:r}` to keep the default formatting of `rax`
 
 warning: formatting may not be suitable for sub-register argument
   --> $DIR/type-check-3.rs:41:15
@@ -72,8 +72,8 @@ warning: formatting may not be suitable for sub-register argument
 LL |         asm!("{}", in(ymm_reg) 0i64);
    |               ^^               ---- for this argument
    |
-   = help: use the `x` modifier to have the register formatted as `xmm0`
-   = help: or use the `y` modifier to keep the default formatting of `ymm0`
+   = help: use `{0:x}` to have the register formatted as `xmm0`
+   = help: or use `{0:y}` to keep the default formatting of `ymm0`
 
 error: type `i8` cannot be used with this register class
   --> $DIR/type-check-3.rs:52:28
diff --git a/src/test/ui/asm/x86_64/type-check-5.stderr b/src/test/ui/asm/x86_64/type-check-5.stderr
index e9c93fea561a..bd90461e52c1 100644
--- a/src/test/ui/asm/x86_64/type-check-5.stderr
+++ b/src/test/ui/asm/x86_64/type-check-5.stderr
@@ -5,6 +5,11 @@ LL |         let x: u64;
    |             - binding declared here but left uninitialized
 LL |         asm!("{}", in(reg) x);
    |                            ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let x: u64 = 0;
+   |                    +++
 
 error[E0381]: used binding `y` isn't initialized
   --> $DIR/type-check-5.rs:18:9
@@ -13,6 +18,11 @@ LL |         let mut y: u64;
    |             ----- binding declared here but left uninitialized
 LL |         asm!("{}", inout(reg) y);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ `y` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let mut y: u64 = 0;
+   |                        +++
 
 error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
   --> $DIR/type-check-5.rs:26:29
diff --git a/src/test/ui/associated-consts/defaults-cyclic-fail.stderr b/src/test/ui/associated-consts/defaults-cyclic-fail.stderr
index ab95137c630f..c4cd9c2a49fd 100644
--- a/src/test/ui/associated-consts/defaults-cyclic-fail.stderr
+++ b/src/test/ui/associated-consts/defaults-cyclic-fail.stderr
@@ -2,13 +2,13 @@ error[E0391]: cycle detected when const-evaluating + checking `Tr::A`
   --> $DIR/defaults-cyclic-fail.rs:5:5
    |
 LL |     const A: u8 = Self::B;
-   |     ^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^
    |
 note: ...which requires const-evaluating + checking `Tr::B`...
   --> $DIR/defaults-cyclic-fail.rs:8:5
    |
 LL |     const B: u8 = Self::A;
-   |     ^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which again requires const-evaluating + checking `Tr::A`, completing the cycle
 note: cycle used when const-evaluating + checking `main::promoted[1]`
   --> $DIR/defaults-cyclic-fail.rs:16:16
diff --git a/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-impl.stderr b/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-impl.stderr
index e682b8e9e6d7..c8c57bccb501 100644
--- a/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-impl.stderr
+++ b/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-impl.stderr
@@ -13,7 +13,7 @@ note: ...which requires const-evaluating + checking `IMPL_REF_BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:7:1
    |
 LL | const IMPL_REF_BAR: u32 = GlobalImplRef::BAR;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires const-evaluating + checking `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 11:19>::BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:5
    |
diff --git a/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait-default.stderr b/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait-default.stderr
index 9b0c1b149018..76ed8d4a6e86 100644
--- a/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait-default.stderr
+++ b/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait-default.stderr
@@ -13,7 +13,7 @@ note: ...which requires const-evaluating + checking `DEFAULT_REF_BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:11:1
    |
 LL | const DEFAULT_REF_BAR: u32 = <GlobalDefaultRef>::BAR;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires const-evaluating + checking `FooDefault::BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
    |
diff --git a/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait.stderr b/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait.stderr
index 48956dcedab8..6a98f08f3d3a 100644
--- a/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait.stderr
+++ b/src/test/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait.stderr
@@ -13,7 +13,7 @@ note: ...which requires const-evaluating + checking `TRAIT_REF_BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:7:1
    |
 LL | const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires const-evaluating + checking `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 11:28>::BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:5
    |
diff --git a/src/test/ui/associated-type-bounds/binder-on-bound.rs b/src/test/ui/associated-type-bounds/binder-on-bound.rs
index 0b4b24b9820b..6cba45129e49 100644
--- a/src/test/ui/associated-type-bounds/binder-on-bound.rs
+++ b/src/test/ui/associated-type-bounds/binder-on-bound.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Trait {
     type Bound<'a>;
 }
diff --git a/src/test/ui/associated-type-bounds/binder-on-bound.stderr b/src/test/ui/associated-type-bounds/binder-on-bound.stderr
index 3432672e03c4..f71f72bfb94f 100644
--- a/src/test/ui/associated-type-bounds/binder-on-bound.stderr
+++ b/src/test/ui/associated-type-bounds/binder-on-bound.stderr
@@ -1,5 +1,5 @@
 error: `for<...>` is not allowed on associated type bounds
-  --> $DIR/binder-on-bound.rs:7:22
+  --> $DIR/binder-on-bound.rs:5:22
    |
 LL | fn foo() where Trait<for<'a> Bound<'a> = &'a ()> {
    |                      ^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/associated-type-bounds/elision.rs b/src/test/ui/associated-type-bounds/elision.rs
index 4a533939931b..d00def571666 100644
--- a/src/test/ui/associated-type-bounds/elision.rs
+++ b/src/test/ui/associated-type-bounds/elision.rs
@@ -1,7 +1,7 @@
 #![feature(associated_type_bounds)]
 #![feature(anonymous_lifetime_in_impl_trait)]
 
-// The same thing should happen for constaints in dyn trait.
+// The same thing should happen for constraints in dyn trait.
 fn f(x: &mut dyn Iterator<Item: Iterator<Item = &'_ ()>>) -> Option<&'_ ()> { x.next() }
 //~^ ERROR missing lifetime specifier
 //~| ERROR mismatched types
diff --git a/src/test/ui/associated-type-bounds/issue-79949.rs b/src/test/ui/associated-type-bounds/issue-79949.rs
index 9f924f1fd81d..9dd37f98150b 100644
--- a/src/test/ui/associated-type-bounds/issue-79949.rs
+++ b/src/test/ui/associated-type-bounds/issue-79949.rs
@@ -2,7 +2,6 @@
 
 #![allow(incomplete_features)]
 #![feature(associated_type_bounds)]
-#![feature(generic_associated_types)]
 
 trait MP {
     type T<'a>;
diff --git a/src/test/ui/associated-types/associated-types-path-2.rs b/src/test/ui/associated-types/associated-types-path-2.rs
index c993e1d27202..00066efccb8d 100644
--- a/src/test/ui/associated-types/associated-types-path-2.rs
+++ b/src/test/ui/associated-types/associated-types-path-2.rs
@@ -29,12 +29,14 @@ pub fn f1_uint_uint() {
     f1(2u32, 4u32);
     //~^ ERROR `u32: Foo` is not satisfied
     //~| ERROR `u32: Foo` is not satisfied
+    //~| ERROR `u32: Foo` is not satisfied
 }
 
 pub fn f1_uint_int() {
     f1(2u32, 4i32);
     //~^ ERROR `u32: Foo` is not satisfied
     //~| ERROR `u32: Foo` is not satisfied
+    //~| ERROR `u32: Foo` is not satisfied
 }
 
 pub fn f2_int() {
diff --git a/src/test/ui/associated-types/associated-types-path-2.stderr b/src/test/ui/associated-types/associated-types-path-2.stderr
index 5edd5c864e13..206f49024102 100644
--- a/src/test/ui/associated-types/associated-types-path-2.stderr
+++ b/src/test/ui/associated-types/associated-types-path-2.stderr
@@ -31,6 +31,14 @@ note: required by a bound in `f1`
 LL | pub fn f1<T: Foo>(a: T, x: T::A) {}
    |              ^^^ required by this bound in `f1`
 
+error[E0277]: the trait bound `u32: Foo` is not satisfied
+  --> $DIR/associated-types-path-2.rs:29:5
+   |
+LL |     f1(2u32, 4u32);
+   |     ^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `u32`
+   |
+   = help: the trait `Foo` is implemented for `i32`
+
 error[E0277]: the trait bound `u32: Foo` is not satisfied
   --> $DIR/associated-types-path-2.rs:29:14
    |
@@ -40,7 +48,7 @@ LL |     f1(2u32, 4u32);
    = help: the trait `Foo` is implemented for `i32`
 
 error[E0277]: the trait bound `u32: Foo` is not satisfied
-  --> $DIR/associated-types-path-2.rs:35:8
+  --> $DIR/associated-types-path-2.rs:36:8
    |
 LL |     f1(2u32, 4i32);
    |     -- ^^^^ the trait `Foo` is not implemented for `u32`
@@ -55,7 +63,15 @@ LL | pub fn f1<T: Foo>(a: T, x: T::A) {}
    |              ^^^ required by this bound in `f1`
 
 error[E0277]: the trait bound `u32: Foo` is not satisfied
-  --> $DIR/associated-types-path-2.rs:35:14
+  --> $DIR/associated-types-path-2.rs:36:5
+   |
+LL |     f1(2u32, 4i32);
+   |     ^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `u32`
+   |
+   = help: the trait `Foo` is implemented for `i32`
+
+error[E0277]: the trait bound `u32: Foo` is not satisfied
+  --> $DIR/associated-types-path-2.rs:36:14
    |
 LL |     f1(2u32, 4i32);
    |              ^^^^ the trait `Foo` is not implemented for `u32`
@@ -63,7 +79,7 @@ LL |     f1(2u32, 4i32);
    = help: the trait `Foo` is implemented for `i32`
 
 error[E0308]: mismatched types
-  --> $DIR/associated-types-path-2.rs:41:18
+  --> $DIR/associated-types-path-2.rs:43:18
    |
 LL |     let _: i32 = f2(2i32);
    |            ---   ^^^^^^^^ expected `i32`, found `u32`
@@ -75,7 +91,7 @@ help: you can convert a `u32` to an `i32` and panic if the converted value doesn
 LL |     let _: i32 = f2(2i32).try_into().unwrap();
    |                          ++++++++++++++++++++
 
-error: aborting due to 6 previous errors
+error: aborting due to 8 previous errors
 
 Some errors have detailed explanations: E0277, E0308.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/associated-types/issue-62200.rs b/src/test/ui/associated-types/issue-62200.rs
index 9d18690e9604..499bbd6b6fad 100644
--- a/src/test/ui/associated-types/issue-62200.rs
+++ b/src/test/ui/associated-types/issue-62200.rs
@@ -10,6 +10,7 @@ impl T<'_> for S {
 
 fn foo(x: impl Fn(<S as T<'_>>::A) -> <S as T<'_>>::A) {}
 //~^ ERROR binding for associated type `Output` references an anonymous lifetime
-//~^^ NOTE lifetimes appearing in an associated type are not considered constrained
+//~| NOTE lifetimes appearing in an associated or opaque type are not considered constrained
+//~| NOTE consider introducing a named lifetime parameter
 
 fn main() {}
diff --git a/src/test/ui/associated-types/issue-62200.stderr b/src/test/ui/associated-types/issue-62200.stderr
index f14cd81fdfe1..04f0728f58ea 100644
--- a/src/test/ui/associated-types/issue-62200.stderr
+++ b/src/test/ui/associated-types/issue-62200.stderr
@@ -4,7 +4,8 @@ error[E0582]: binding for associated type `Output` references an anonymous lifet
 LL | fn foo(x: impl Fn(<S as T<'_>>::A) -> <S as T<'_>>::A) {}
    |                                       ^^^^^^^^^^^^^^^
    |
-   = note: lifetimes appearing in an associated type are not considered constrained
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/async-await/async-await-let-else.drop-tracking.stderr b/src/test/ui/async-await/async-await-let-else.drop-tracking.stderr
new file mode 100644
index 000000000000..3be7f370da3f
--- /dev/null
+++ b/src/test/ui/async-await/async-await-let-else.drop-tracking.stderr
@@ -0,0 +1,110 @@
+error: future cannot be sent between threads safely
+  --> $DIR/async-await-let-else.rs:48:13
+   |
+LL |     is_send(foo(Some(true)));
+   |             ^^^^^^^^^^^^^^^ future returned by `foo` is not `Send`
+   |
+   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
+note: future is not `Send` as this value is used across an await
+  --> $DIR/async-await-let-else.rs:11:14
+   |
+LL |         let r = Rc::new(());
+   |             - has type `Rc<()>` which is not `Send`
+LL |         bar().await
+   |              ^^^^^^ await occurs here, with `r` maybe used later
+LL |     };
+   |     - `r` is later dropped here
+note: required by a bound in `is_send`
+  --> $DIR/async-await-let-else.rs:19:15
+   |
+LL | fn is_send<T: Send>(_: T) {}
+   |               ^^^^ required by this bound in `is_send`
+
+error[E0277]: `Rc<()>` cannot be sent between threads safely
+  --> $DIR/async-await-let-else.rs:50:13
+   |
+LL | async fn foo2(x: Option<bool>) {
+   |                                - within this `impl Future<Output = ()>`
+...
+LL |     is_send(foo2(Some(true)));
+   |     ------- ^^^^^^^^^^^^^^^^ `Rc<()>` cannot be sent between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
+note: required because it's used within this `async fn` body
+  --> $DIR/async-await-let-else.rs:27:29
+   |
+LL |   async fn bar2<T>(_: T) -> ! {
+   |  _____________________________^
+LL | |     panic!()
+LL | | }
+   | |_^
+   = note: required because it captures the following types: `ResumeTy`, `Option<bool>`, `impl Future<Output = !>`, `()`
+note: required because it's used within this `async fn` body
+  --> $DIR/async-await-let-else.rs:21:32
+   |
+LL |   async fn foo2(x: Option<bool>) {
+   |  ________________________________^
+LL | |     let Some(_) = x else {
+LL | |         bar2(Rc::new(())).await
+LL | |     };
+LL | | }
+   | |_^
+note: required by a bound in `is_send`
+  --> $DIR/async-await-let-else.rs:19:15
+   |
+LL | fn is_send<T: Send>(_: T) {}
+   |               ^^^^ required by this bound in `is_send`
+
+error: future cannot be sent between threads safely
+  --> $DIR/async-await-let-else.rs:52:13
+   |
+LL |     is_send(foo3(Some(true)));
+   |             ^^^^^^^^^^^^^^^^ future returned by `foo3` is not `Send`
+   |
+   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
+note: future is not `Send` as this value is used across an await
+  --> $DIR/async-await-let-else.rs:33:28
+   |
+LL |         (Rc::new(()), bar().await);
+   |          -----------       ^^^^^^ await occurs here, with `Rc::new(())` maybe used later
+   |          |
+   |          has type `Rc<()>` which is not `Send`
+note: `Rc::new(())` is later dropped here
+  --> $DIR/async-await-let-else.rs:33:35
+   |
+LL |         (Rc::new(()), bar().await);
+   |                                   ^
+note: required by a bound in `is_send`
+  --> $DIR/async-await-let-else.rs:19:15
+   |
+LL | fn is_send<T: Send>(_: T) {}
+   |               ^^^^ required by this bound in `is_send`
+
+error: future cannot be sent between threads safely
+  --> $DIR/async-await-let-else.rs:54:13
+   |
+LL |     is_send(foo4(Some(true)));
+   |             ^^^^^^^^^^^^^^^^ future returned by `foo4` is not `Send`
+   |
+   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
+note: future is not `Send` as this value is used across an await
+  --> $DIR/async-await-let-else.rs:41:14
+   |
+LL |         let r = Rc::new(());
+   |             - has type `Rc<()>` which is not `Send`
+LL |         bar().await;
+   |              ^^^^^^ await occurs here, with `r` maybe used later
+...
+LL |     };
+   |     - `r` is later dropped here
+note: required by a bound in `is_send`
+  --> $DIR/async-await-let-else.rs:19:15
+   |
+LL | fn is_send<T: Send>(_: T) {}
+   |               ^^^^ required by this bound in `is_send`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/async-await/async-await-let-else.stderr b/src/test/ui/async-await/async-await-let-else.no-drop-tracking.stderr
similarity index 83%
rename from src/test/ui/async-await/async-await-let-else.stderr
rename to src/test/ui/async-await/async-await-let-else.no-drop-tracking.stderr
index 4d23e27c426b..7f93563e2884 100644
--- a/src/test/ui/async-await/async-await-let-else.stderr
+++ b/src/test/ui/async-await/async-await-let-else.no-drop-tracking.stderr
@@ -1,12 +1,12 @@
 error: future cannot be sent between threads safely
-  --> $DIR/async-await-let-else.rs:45:13
+  --> $DIR/async-await-let-else.rs:48:13
    |
 LL |     is_send(foo(Some(true)));
    |             ^^^^^^^^^^^^^^^ future returned by `foo` is not `Send`
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/async-await-let-else.rs:8:14
+  --> $DIR/async-await-let-else.rs:11:14
    |
 LL |         let r = Rc::new(());
    |             - has type `Rc<()>` which is not `Send`
@@ -15,67 +15,67 @@ LL |         bar().await
 LL |     };
    |     - `r` is later dropped here
 note: required by a bound in `is_send`
-  --> $DIR/async-await-let-else.rs:16:15
+  --> $DIR/async-await-let-else.rs:19:15
    |
 LL | fn is_send<T: Send>(_: T) {}
    |               ^^^^ required by this bound in `is_send`
 
 error: future cannot be sent between threads safely
-  --> $DIR/async-await-let-else.rs:47:13
+  --> $DIR/async-await-let-else.rs:50:13
    |
 LL |     is_send(foo2(Some(true)));
    |             ^^^^^^^^^^^^^^^^ future returned by `foo2` is not `Send`
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/async-await-let-else.rs:20:26
+  --> $DIR/async-await-let-else.rs:23:26
    |
 LL |         bar2(Rc::new(())).await
    |              ----------- ^^^^^^ await occurs here, with `Rc::new(())` maybe used later
    |              |
    |              has type `Rc<()>` which is not `Send`
 LL |     };
-   |      - `Rc::new(())` is later dropped here
+   |     - `Rc::new(())` is later dropped here
 note: required by a bound in `is_send`
-  --> $DIR/async-await-let-else.rs:16:15
+  --> $DIR/async-await-let-else.rs:19:15
    |
 LL | fn is_send<T: Send>(_: T) {}
    |               ^^^^ required by this bound in `is_send`
 
 error: future cannot be sent between threads safely
-  --> $DIR/async-await-let-else.rs:49:13
+  --> $DIR/async-await-let-else.rs:52:13
    |
 LL |     is_send(foo3(Some(true)));
    |             ^^^^^^^^^^^^^^^^ future returned by `foo3` is not `Send`
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/async-await-let-else.rs:30:28
+  --> $DIR/async-await-let-else.rs:33:28
    |
 LL |         (Rc::new(()), bar().await);
    |          -----------       ^^^^^^ await occurs here, with `Rc::new(())` maybe used later
    |          |
    |          has type `Rc<()>` which is not `Send`
 note: `Rc::new(())` is later dropped here
-  --> $DIR/async-await-let-else.rs:30:35
+  --> $DIR/async-await-let-else.rs:33:35
    |
 LL |         (Rc::new(()), bar().await);
    |                                   ^
 note: required by a bound in `is_send`
-  --> $DIR/async-await-let-else.rs:16:15
+  --> $DIR/async-await-let-else.rs:19:15
    |
 LL | fn is_send<T: Send>(_: T) {}
    |               ^^^^ required by this bound in `is_send`
 
 error: future cannot be sent between threads safely
-  --> $DIR/async-await-let-else.rs:51:13
+  --> $DIR/async-await-let-else.rs:54:13
    |
 LL |     is_send(foo4(Some(true)));
    |             ^^^^^^^^^^^^^^^^ future returned by `foo4` is not `Send`
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/async-await-let-else.rs:38:14
+  --> $DIR/async-await-let-else.rs:41:14
    |
 LL |         let r = Rc::new(());
    |             - has type `Rc<()>` which is not `Send`
@@ -85,7 +85,7 @@ LL |         bar().await;
 LL |     };
    |     - `r` is later dropped here
 note: required by a bound in `is_send`
-  --> $DIR/async-await-let-else.rs:16:15
+  --> $DIR/async-await-let-else.rs:19:15
    |
 LL | fn is_send<T: Send>(_: T) {}
    |               ^^^^ required by this bound in `is_send`
diff --git a/src/test/ui/async-await/async-await-let-else.rs b/src/test/ui/async-await/async-await-let-else.rs
index 7ea07ae9add1..3fb2142b9e5d 100644
--- a/src/test/ui/async-await/async-await-let-else.rs
+++ b/src/test/ui/async-await/async-await-let-else.rs
@@ -1,5 +1,8 @@
 // edition:2021
-#![feature(let_else)]
+// revisions: drop-tracking no-drop-tracking
+// [drop-tracking] compile-flags: -Zdrop-tracking=yes
+// [no-drop-tracking] compile-flags: -Zdrop-tracking=no
+
 use std::rc::Rc;
 
 async fn foo(x: Option<bool>) {
@@ -43,11 +46,11 @@ async fn foo4(x: Option<bool>) {
 
 fn main() {
     is_send(foo(Some(true)));
-    //~^ ERROR future cannot be sent between threads safely
+    //~^ ERROR cannot be sent between threads safely
     is_send(foo2(Some(true)));
-    //~^ ERROR future cannot be sent between threads safely
+    //~^ ERROR cannot be sent between threads safely
     is_send(foo3(Some(true)));
-    //~^ ERROR future cannot be sent between threads safely
+    //~^ ERROR cannot be sent between threads safely
     is_send(foo4(Some(true)));
-    //~^ ERROR future cannot be sent between threads safely
+    //~^ ERROR cannot be sent between threads safely
 }
diff --git a/src/test/ui/async-await/async-fn-size-moved-locals.rs b/src/test/ui/async-await/async-fn-size-moved-locals.rs
index 15566256600d..79b7239f3590 100644
--- a/src/test/ui/async-await/async-fn-size-moved-locals.rs
+++ b/src/test/ui/async-await/async-fn-size-moved-locals.rs
@@ -7,7 +7,7 @@
 //
 // See issue #59123 for a full explanation.
 
-// ignore-emscripten (sizes don't match)
+// needs-unwind Size of Futures change on panic=abort
 // run-pass
 
 // edition:2018
diff --git a/src/test/ui/async-await/async-fn-size-uninit-locals.rs b/src/test/ui/async-await/async-fn-size-uninit-locals.rs
index 31a086ba9756..546172693545 100644
--- a/src/test/ui/async-await/async-fn-size-uninit-locals.rs
+++ b/src/test/ui/async-await/async-fn-size-uninit-locals.rs
@@ -5,6 +5,7 @@
 // being reflected in the size.
 
 // ignore-emscripten (sizes don't match)
+// needs-unwind Size of Futures change on panic=abort
 // run-pass
 
 // edition:2018
@@ -67,9 +68,7 @@ async fn joined() {
     let c = Big::new();
 
     fut().await;
-    noop();
     joiner = Joiner { a: Some(a), b: Some(b), c: Some(c) };
-    noop();
 }
 
 async fn joined_with_noop() {
@@ -97,7 +96,7 @@ async fn join_retval() -> Joiner {
 fn main() {
     assert_eq!(2, std::mem::size_of_val(&single()));
     assert_eq!(3, std::mem::size_of_val(&single_with_noop()));
-    assert_eq!(3078, std::mem::size_of_val(&joined()));
+    assert_eq!(3074, std::mem::size_of_val(&joined()));
     assert_eq!(3078, std::mem::size_of_val(&joined_with_noop()));
     assert_eq!(3074, std::mem::size_of_val(&join_retval()));
 }
diff --git a/src/test/ui/async-await/async-trait-fn.rs b/src/test/ui/async-await/async-trait-fn.rs
index e2062e82725c..0ea685986db4 100644
--- a/src/test/ui/async-await/async-trait-fn.rs
+++ b/src/test/ui/async-await/async-trait-fn.rs
@@ -1,8 +1,11 @@
 // edition:2018
 trait T {
     async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
+    //~^ ERROR mismatched types
     async fn bar(&self) {} //~ ERROR functions in traits cannot be declared `async`
+    //~^ ERROR mismatched types
     async fn baz() { //~ ERROR functions in traits cannot be declared `async`
+        //~^ ERROR mismatched types
         // Nested item must not ICE.
         fn a() {}
     }
diff --git a/src/test/ui/async-await/async-trait-fn.stderr b/src/test/ui/async-await/async-trait-fn.stderr
index 1eb8969a80d2..4fa54c6e3696 100644
--- a/src/test/ui/async-await/async-trait-fn.stderr
+++ b/src/test/ui/async-await/async-trait-fn.stderr
@@ -2,40 +2,89 @@ error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/async-trait-fn.rs:3:5
    |
 LL |     async fn foo() {}
-   |     -----^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:4:5
-   |
-LL |     async fn bar(&self) {}
-   |     -----^^^^^^^^^^^^^^^^^
+   |     -----^^^^^^^^^
    |     |
    |     `async` because of this
    |
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
 error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/async-trait-fn.rs:5:5
    |
-LL |       async fn baz() {
-   |       ^----
-   |       |
-   |  _____`async` because of this
-   | |
-LL | |         // Nested item must not ICE.
-LL | |         fn a() {}
-LL | |     }
-   | |_____^
+LL |     async fn bar(&self) {}
+   |     -----^^^^^^^^^^^^^^
+   |     |
+   |     `async` because of this
    |
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
-error: aborting due to 3 previous errors
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/async-trait-fn.rs:7:5
+   |
+LL |     async fn baz() {
+   |     -----^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
-For more information about this error, try `rustc --explain E0706`.
+error[E0308]: mismatched types
+  --> $DIR/async-trait-fn.rs:3:20
+   |
+LL |     async fn foo() {}
+   |                    ^^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                           ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn.rs:3:20>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
+error[E0308]: mismatched types
+  --> $DIR/async-trait-fn.rs:5:25
+   |
+LL |     async fn bar(&self) {}
+   |                         ^^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                           ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn.rs:5:25>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
+error[E0308]: mismatched types
+  --> $DIR/async-trait-fn.rs:7:20
+   |
+LL |       async fn baz() {
+   |  ____________________^
+LL | |
+LL | |         // Nested item must not ICE.
+LL | |         fn a() {}
+LL | |     }
+   | |_____^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL |   pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                             ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn.rs:7:20>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0308, E0706.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/async-await/edition-deny-async-fns-2015.rs b/src/test/ui/async-await/edition-deny-async-fns-2015.rs
index e5dc9c8a5fee..22a61dcd25f9 100644
--- a/src/test/ui/async-await/edition-deny-async-fns-2015.rs
+++ b/src/test/ui/async-await/edition-deny-async-fns-2015.rs
@@ -16,7 +16,8 @@ impl Foo {
 
 trait Bar {
     async fn foo() {} //~ ERROR `async fn` is not permitted in Rust 2015
-                      //~^ ERROR functions in traits cannot be declared `async`
+    //~^ ERROR functions in traits cannot be declared `async`
+    //~| ERROR mismatched types
 }
 
 fn main() {
diff --git a/src/test/ui/async-await/edition-deny-async-fns-2015.stderr b/src/test/ui/async-await/edition-deny-async-fns-2015.stderr
index 35f9c581c7b2..62a243e69e74 100644
--- a/src/test/ui/async-await/edition-deny-async-fns-2015.stderr
+++ b/src/test/ui/async-await/edition-deny-async-fns-2015.stderr
@@ -53,7 +53,7 @@ LL |     async fn foo() {}
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
 error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:36:9
+  --> $DIR/edition-deny-async-fns-2015.rs:37:9
    |
 LL |         async fn bar() {}
    |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
@@ -62,7 +62,7 @@ LL |         async fn bar() {}
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
 error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:26:9
+  --> $DIR/edition-deny-async-fns-2015.rs:27:9
    |
 LL |         async fn foo() {}
    |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
@@ -71,7 +71,7 @@ LL |         async fn foo() {}
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
 error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:31:13
+  --> $DIR/edition-deny-async-fns-2015.rs:32:13
    |
 LL |             async fn bar() {}
    |             ^^^^^ to use `async fn`, switch to Rust 2018 or later
@@ -83,14 +83,30 @@ error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/edition-deny-async-fns-2015.rs:18:5
    |
 LL |     async fn foo() {}
-   |     -----^^^^^^^^^^^^
+   |     -----^^^^^^^^^
    |     |
    |     `async` because of this
    |
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
-error: aborting due to 10 previous errors
+error[E0308]: mismatched types
+  --> $DIR/edition-deny-async-fns-2015.rs:18:20
+   |
+LL |     async fn foo() {}
+   |                    ^^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                           ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/edition-deny-async-fns-2015.rs:18:20>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
 
-Some errors have detailed explanations: E0670, E0706.
-For more information about an error, try `rustc --explain E0670`.
+error: aborting due to 11 previous errors
+
+Some errors have detailed explanations: E0308, E0670, E0706.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/async-await/feature-gate-async_fn_in_trait.rs b/src/test/ui/async-await/feature-gate-async_fn_in_trait.rs
new file mode 100644
index 000000000000..792f378cb57f
--- /dev/null
+++ b/src/test/ui/async-await/feature-gate-async_fn_in_trait.rs
@@ -0,0 +1,25 @@
+// edition:2021
+
+// RPITIT is not enough to allow use of async functions
+#![allow(incomplete_features)]
+#![feature(return_position_impl_trait_in_trait)]
+
+trait T {
+    async fn foo(); //~ ERROR functions in traits cannot be declared `async`
+}
+
+// Both return_position_impl_trait_in_trait and async_fn_in_trait are required for this (see also
+// feature-gate-return_position_impl_trait_in_trait.rs)
+trait T2 {
+    async fn foo() -> impl Sized; //~ ERROR functions in traits cannot be declared `async`
+}
+
+trait T3 {
+    fn foo() -> impl std::future::Future<Output = ()>;
+}
+
+impl T3 for () {
+    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/feature-gate-async_fn_in_trait.stderr b/src/test/ui/async-await/feature-gate-async_fn_in_trait.stderr
new file mode 100644
index 000000000000..2a5fbd1ecd03
--- /dev/null
+++ b/src/test/ui/async-await/feature-gate-async_fn_in_trait.stderr
@@ -0,0 +1,42 @@
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/feature-gate-async_fn_in_trait.rs:8:5
+   |
+LL |     async fn foo();
+   |     -----^^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/feature-gate-async_fn_in_trait.rs:14:5
+   |
+LL |     async fn foo() -> impl Sized;
+   |     -----^^^^^^^^^^^^^^^^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/feature-gate-async_fn_in_trait.rs:22:5
+   |
+LL |     async fn foo() {}
+   |     -----^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0706`.
diff --git a/src/test/ui/async-await/in-trait/issue-102138.rs b/src/test/ui/async-await/in-trait/issue-102138.rs
new file mode 100644
index 000000000000..f61b34ed99e0
--- /dev/null
+++ b/src/test/ui/async-await/in-trait/issue-102138.rs
@@ -0,0 +1,46 @@
+// check-pass
+// edition:2021
+
+#![feature(async_fn_in_trait)]
+#![allow(incomplete_features)]
+
+use std::future::Future;
+
+async fn yield_now() {}
+
+trait AsyncIterator {
+    type Item;
+    async fn next(&mut self) -> Option<Self::Item>;
+}
+
+struct YieldingRange {
+    counter: u32,
+    stop: u32,
+}
+
+impl AsyncIterator for YieldingRange {
+    type Item = u32;
+
+    async fn next(&mut self) -> Option<Self::Item> {
+        if self.counter == self.stop {
+            None
+        } else {
+            let c = self.counter;
+            self.counter += 1;
+            yield_now().await;
+            Some(c)
+        }
+    }
+}
+
+async fn async_main() {
+    let mut x = YieldingRange { counter: 0, stop: 10 };
+
+    while let Some(v) = x.next().await {
+        println!("Hi: {v}");
+    }
+}
+
+fn main() {
+    let _ = async_main();
+}
diff --git a/src/test/ui/async-await/in-trait/issue-102219.rs b/src/test/ui/async-await/in-trait/issue-102219.rs
new file mode 100644
index 000000000000..9a35f6515cb1
--- /dev/null
+++ b/src/test/ui/async-await/in-trait/issue-102219.rs
@@ -0,0 +1,10 @@
+// compile-flags:--crate-type=lib
+// edition:2021
+// check-pass
+
+#![feature(async_fn_in_trait)]
+#![allow(incomplete_features)]
+
+trait T {
+    async fn foo();
+}
diff --git a/src/test/ui/async-await/issue-101715.rs b/src/test/ui/async-await/issue-101715.rs
new file mode 100644
index 000000000000..1be5d02482e8
--- /dev/null
+++ b/src/test/ui/async-await/issue-101715.rs
@@ -0,0 +1,17 @@
+// edition:2018
+
+struct S;
+
+impl S {
+    fn very_long_method_name_the_longest_method_name_in_the_whole_universe(self) {}
+}
+
+async fn foo() {
+    S.very_long_method_name_the_longest_method_name_in_the_whole_universe()
+        .await
+        //~^ error: `()` is not a future
+        //~| help: remove the `.await`
+        //~| help: the trait `Future` is not implemented for `()`
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/issue-101715.stderr b/src/test/ui/async-await/issue-101715.stderr
new file mode 100644
index 000000000000..a0e8d2a89437
--- /dev/null
+++ b/src/test/ui/async-await/issue-101715.stderr
@@ -0,0 +1,16 @@
+error[E0277]: `()` is not a future
+  --> $DIR/issue-101715.rs:11:9
+   |
+LL |         .await
+   |         ^^^^^^
+   |         |
+   |         `()` is not a future
+   |         help: remove the `.await`
+   |
+   = help: the trait `Future` is not implemented for `()`
+   = note: () must be a future or must implement `IntoFuture` to be awaited
+   = note: required for `()` to implement `IntoFuture`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/async-await/issue-64130-4-async-move.stderr b/src/test/ui/async-await/issue-64130-4-async-move.drop-tracking.stderr
similarity index 86%
rename from src/test/ui/async-await/issue-64130-4-async-move.stderr
rename to src/test/ui/async-await/issue-64130-4-async-move.drop-tracking.stderr
index d631e6dc7f7e..f609e36362c4 100644
--- a/src/test/ui/async-await/issue-64130-4-async-move.stderr
+++ b/src/test/ui/async-await/issue-64130-4-async-move.drop-tracking.stderr
@@ -1,12 +1,12 @@
 error: future cannot be sent between threads safely
-  --> $DIR/issue-64130-4-async-move.rs:15:17
+  --> $DIR/issue-64130-4-async-move.rs:19:17
    |
 LL | pub fn foo() -> impl Future + Send {
    |                 ^^^^^^^^^^^^^^^^^^ future created by async block is not `Send`
    |
    = help: the trait `Sync` is not implemented for `(dyn Any + Send + 'static)`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/issue-64130-4-async-move.rs:21:31
+  --> $DIR/issue-64130-4-async-move.rs:25:31
    |
 LL |         match client.status() {
    |               ------ has type `&Client` which is not `Send`
@@ -17,7 +17,7 @@ LL |                 let _x = get().await;
 LL |     }
    |     - `client` is later dropped here
 help: consider moving this into a `let` binding to create a shorter lived borrow
-  --> $DIR/issue-64130-4-async-move.rs:19:15
+  --> $DIR/issue-64130-4-async-move.rs:23:15
    |
 LL |         match client.status() {
    |               ^^^^^^^^^^^^^^^
diff --git a/src/test/ui/async-await/issue-64130-4-async-move.no_drop_tracking.stderr b/src/test/ui/async-await/issue-64130-4-async-move.no_drop_tracking.stderr
new file mode 100644
index 000000000000..f609e36362c4
--- /dev/null
+++ b/src/test/ui/async-await/issue-64130-4-async-move.no_drop_tracking.stderr
@@ -0,0 +1,26 @@
+error: future cannot be sent between threads safely
+  --> $DIR/issue-64130-4-async-move.rs:19:17
+   |
+LL | pub fn foo() -> impl Future + Send {
+   |                 ^^^^^^^^^^^^^^^^^^ future created by async block is not `Send`
+   |
+   = help: the trait `Sync` is not implemented for `(dyn Any + Send + 'static)`
+note: future is not `Send` as this value is used across an await
+  --> $DIR/issue-64130-4-async-move.rs:25:31
+   |
+LL |         match client.status() {
+   |               ------ has type `&Client` which is not `Send`
+LL |             200 => {
+LL |                 let _x = get().await;
+   |                               ^^^^^^ await occurs here, with `client` maybe used later
+...
+LL |     }
+   |     - `client` is later dropped here
+help: consider moving this into a `let` binding to create a shorter lived borrow
+  --> $DIR/issue-64130-4-async-move.rs:23:15
+   |
+LL |         match client.status() {
+   |               ^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/async-await/issue-64130-4-async-move.rs b/src/test/ui/async-await/issue-64130-4-async-move.rs
index 2538f34351e5..a38428fc00f0 100644
--- a/src/test/ui/async-await/issue-64130-4-async-move.rs
+++ b/src/test/ui/async-await/issue-64130-4-async-move.rs
@@ -1,4 +1,8 @@
 // edition:2018
+// revisions: no_drop_tracking drop_tracking
+// [drop_tracking] check-pass
+// [drop_tracking] compile-flags: -Zdrop-tracking=yes
+// [no_drop_tracking] compile-flags: -Zdrop-tracking=no
 use std::any::Any;
 use std::future::Future;
 
@@ -10,16 +14,16 @@ impl Client {
     }
 }
 
-async fn get() { }
+async fn get() {}
 
 pub fn foo() -> impl Future + Send {
-    //~^ ERROR future cannot be sent between threads safely
+    //[no_drop_tracking]~^ ERROR future cannot be sent between threads safely
     let client = Client(Box::new(true));
     async move {
         match client.status() {
             200 => {
                 let _x = get().await;
-            },
+            }
             _ => (),
         }
     }
diff --git a/src/test/ui/async-await/issue-68112.drop_tracking.stderr b/src/test/ui/async-await/issue-68112.drop_tracking.stderr
new file mode 100644
index 000000000000..c915164cfce8
--- /dev/null
+++ b/src/test/ui/async-await/issue-68112.drop_tracking.stderr
@@ -0,0 +1,79 @@
+error: future cannot be sent between threads safely
+  --> $DIR/issue-68112.rs:37:18
+   |
+LL |     require_send(send_fut);
+   |                  ^^^^^^^^ future created by async block is not `Send`
+   |
+   = help: the trait `Sync` is not implemented for `RefCell<i32>`
+note: future is not `Send` as it awaits another future which is not `Send`
+  --> $DIR/issue-68112.rs:34:17
+   |
+LL |         let _ = non_send_fut.await;
+   |                 ^^^^^^^^^^^^ await occurs here on type `impl Future<Output = Arc<RefCell<i32>>>`, which is not `Send`
+note: required by a bound in `require_send`
+  --> $DIR/issue-68112.rs:14:25
+   |
+LL | fn require_send(_: impl Send) {}
+   |                         ^^^^ required by this bound in `require_send`
+
+error: future cannot be sent between threads safely
+  --> $DIR/issue-68112.rs:46:18
+   |
+LL |     require_send(send_fut);
+   |                  ^^^^^^^^ future created by async block is not `Send`
+   |
+   = help: the trait `Sync` is not implemented for `RefCell<i32>`
+note: future is not `Send` as it awaits another future which is not `Send`
+  --> $DIR/issue-68112.rs:43:17
+   |
+LL |         let _ = make_non_send_future1().await;
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^ await occurs here on type `impl Future<Output = Arc<RefCell<i32>>>`, which is not `Send`
+note: required by a bound in `require_send`
+  --> $DIR/issue-68112.rs:14:25
+   |
+LL | fn require_send(_: impl Send) {}
+   |                         ^^^^ required by this bound in `require_send`
+
+error[E0277]: `RefCell<i32>` cannot be shared between threads safely
+  --> $DIR/issue-68112.rs:65:18
+   |
+LL |     require_send(send_fut);
+   |     ------------ ^^^^^^^^ `RefCell<i32>` cannot be shared between threads safely
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `Sync` is not implemented for `RefCell<i32>`
+   = note: required for `Arc<RefCell<i32>>` to implement `Send`
+note: required because it's used within this `async fn` body
+  --> $DIR/issue-68112.rs:50:31
+   |
+LL |   async fn ready2<T>(t: T) -> T {
+   |  _______________________________^
+LL | |     t
+LL | | }
+   | |_^
+note: required because it appears within the type `impl Future<Output = Arc<RefCell<i32>>>`
+  --> $DIR/issue-68112.rs:53:31
+   |
+LL | fn make_non_send_future2() -> impl Future<Output = Arc<RefCell<i32>>> {
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: required because it captures the following types: `ResumeTy`, `impl Future<Output = Arc<RefCell<i32>>>`, `()`, `Ready<i32>`
+note: required because it's used within this `async` block
+  --> $DIR/issue-68112.rs:60:26
+   |
+LL |       let send_fut = async {
+   |  __________________________^
+LL | |         let non_send_fut = make_non_send_future2();
+LL | |         let _ = non_send_fut.await;
+LL | |         ready(0).await;
+LL | |     };
+   | |_____^
+note: required by a bound in `require_send`
+  --> $DIR/issue-68112.rs:14:25
+   |
+LL | fn require_send(_: impl Send) {}
+   |                         ^^^^ required by this bound in `require_send`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/async-await/issue-68112.stderr b/src/test/ui/async-await/issue-68112.no_drop_tracking.stderr
similarity index 85%
rename from src/test/ui/async-await/issue-68112.stderr
rename to src/test/ui/async-await/issue-68112.no_drop_tracking.stderr
index c3553e3e0c1c..11b7d1aaaa6c 100644
--- a/src/test/ui/async-await/issue-68112.stderr
+++ b/src/test/ui/async-await/issue-68112.no_drop_tracking.stderr
@@ -1,41 +1,41 @@
 error: future cannot be sent between threads safely
-  --> $DIR/issue-68112.rs:34:18
+  --> $DIR/issue-68112.rs:37:18
    |
 LL |     require_send(send_fut);
    |                  ^^^^^^^^ future created by async block is not `Send`
    |
    = help: the trait `Sync` is not implemented for `RefCell<i32>`
 note: future is not `Send` as it awaits another future which is not `Send`
-  --> $DIR/issue-68112.rs:31:17
+  --> $DIR/issue-68112.rs:34:17
    |
 LL |         let _ = non_send_fut.await;
    |                 ^^^^^^^^^^^^ await occurs here on type `impl Future<Output = Arc<RefCell<i32>>>`, which is not `Send`
 note: required by a bound in `require_send`
-  --> $DIR/issue-68112.rs:11:25
+  --> $DIR/issue-68112.rs:14:25
    |
 LL | fn require_send(_: impl Send) {}
    |                         ^^^^ required by this bound in `require_send`
 
 error: future cannot be sent between threads safely
-  --> $DIR/issue-68112.rs:43:18
+  --> $DIR/issue-68112.rs:46:18
    |
 LL |     require_send(send_fut);
    |                  ^^^^^^^^ future created by async block is not `Send`
    |
    = help: the trait `Sync` is not implemented for `RefCell<i32>`
 note: future is not `Send` as it awaits another future which is not `Send`
-  --> $DIR/issue-68112.rs:40:17
+  --> $DIR/issue-68112.rs:43:17
    |
 LL |         let _ = make_non_send_future1().await;
    |                 ^^^^^^^^^^^^^^^^^^^^^^^ await occurs here on type `impl Future<Output = Arc<RefCell<i32>>>`, which is not `Send`
 note: required by a bound in `require_send`
-  --> $DIR/issue-68112.rs:11:25
+  --> $DIR/issue-68112.rs:14:25
    |
 LL | fn require_send(_: impl Send) {}
    |                         ^^^^ required by this bound in `require_send`
 
 error[E0277]: `RefCell<i32>` cannot be shared between threads safely
-  --> $DIR/issue-68112.rs:60:18
+  --> $DIR/issue-68112.rs:65:18
    |
 LL |     require_send(send_fut);
    |     ------------ ^^^^^^^^ `RefCell<i32>` cannot be shared between threads safely
@@ -45,18 +45,21 @@ LL |     require_send(send_fut);
    = help: the trait `Sync` is not implemented for `RefCell<i32>`
    = note: required for `Arc<RefCell<i32>>` to implement `Send`
 note: required because it's used within this `async fn` body
-  --> $DIR/issue-68112.rs:47:31
+  --> $DIR/issue-68112.rs:50:31
    |
-LL | async fn ready2<T>(t: T) -> T { t }
-   |                               ^^^^^
+LL |   async fn ready2<T>(t: T) -> T {
+   |  _______________________________^
+LL | |     t
+LL | | }
+   | |_^
 note: required because it appears within the type `impl Future<Output = Arc<RefCell<i32>>>`
-  --> $DIR/issue-68112.rs:48:31
+  --> $DIR/issue-68112.rs:53:31
    |
 LL | fn make_non_send_future2() -> impl Future<Output = Arc<RefCell<i32>>> {
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: required because it captures the following types: `ResumeTy`, `impl Future<Output = Arc<RefCell<i32>>>`, `()`, `i32`, `Ready<i32>`
 note: required because it's used within this `async` block
-  --> $DIR/issue-68112.rs:55:26
+  --> $DIR/issue-68112.rs:60:26
    |
 LL |       let send_fut = async {
    |  __________________________^
@@ -66,7 +69,7 @@ LL | |         ready(0).await;
 LL | |     };
    | |_____^
 note: required by a bound in `require_send`
-  --> $DIR/issue-68112.rs:11:25
+  --> $DIR/issue-68112.rs:14:25
    |
 LL | fn require_send(_: impl Send) {}
    |                         ^^^^ required by this bound in `require_send`
diff --git a/src/test/ui/async-await/issue-68112.rs b/src/test/ui/async-await/issue-68112.rs
index bfabf81d1f54..9c705137a105 100644
--- a/src/test/ui/async-await/issue-68112.rs
+++ b/src/test/ui/async-await/issue-68112.rs
@@ -1,10 +1,13 @@
 // edition:2018
+// revisions: no_drop_tracking drop_tracking
+// [drop_tracking] compile-flags: -Zdrop-tracking=yes
+// [no_drop_tracking] compile-flags: -Zdrop-tracking=no
 
 use std::{
-    future::Future,
     cell::RefCell,
-    sync::Arc,
+    future::Future,
     pin::Pin,
+    sync::Arc,
     task::{Context, Poll},
 };
 
@@ -44,7 +47,9 @@ fn test1_no_let() {
     //~^ ERROR future cannot be sent between threads
 }
 
-async fn ready2<T>(t: T) -> T { t }
+async fn ready2<T>(t: T) -> T {
+    t
+}
 fn make_non_send_future2() -> impl Future<Output = Arc<RefCell<i32>>> {
     ready2(Arc::new(RefCell::new(0)))
 }
diff --git a/src/test/ui/async-await/issue-70594.stderr b/src/test/ui/async-await/issue-70594.stderr
index f6ff52a5fd29..d3cf57d3b140 100644
--- a/src/test/ui/async-await/issue-70594.stderr
+++ b/src/test/ui/async-await/issue-70594.stderr
@@ -22,16 +22,14 @@ error[E0277]: `()` is not a future
   --> $DIR/issue-70594.rs:4:11
    |
 LL |     [1; ().await];
-   |           ^^^^^^ `()` is not a future
+   |           ^^^^^^
+   |           |
+   |           `()` is not a future
+   |           help: remove the `.await`
    |
    = help: the trait `Future` is not implemented for `()`
    = note: () must be a future or must implement `IntoFuture` to be awaited
    = note: required for `()` to implement `IntoFuture`
-help: remove the `.await`
-   |
-LL -     [1; ().await];
-LL +     [1; ()];
-   |
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/async-await/issue-70935-complex-spans.drop_tracking.stderr b/src/test/ui/async-await/issue-70935-complex-spans.drop_tracking.stderr
index d2e388c78ca4..85f7d1dd6748 100644
--- a/src/test/ui/async-await/issue-70935-complex-spans.drop_tracking.stderr
+++ b/src/test/ui/async-await/issue-70935-complex-spans.drop_tracking.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `Sender<i32>` cannot be shared between threads safely
-  --> $DIR/issue-70935-complex-spans.rs:12:45
+  --> $DIR/issue-70935-complex-spans.rs:13:45
    |
 LL | fn foo(tx: std::sync::mpsc::Sender<i32>) -> impl Future + Send {
    |                                             ^^^^^^^^^^^^^^^^^^ `Sender<i32>` cannot be shared between threads safely
@@ -7,20 +7,20 @@ LL | fn foo(tx: std::sync::mpsc::Sender<i32>) -> impl Future + Send {
    = help: the trait `Sync` is not implemented for `Sender<i32>`
    = note: required for `&Sender<i32>` to implement `Send`
 note: required because it's used within this closure
-  --> $DIR/issue-70935-complex-spans.rs:16:13
+  --> $DIR/issue-70935-complex-spans.rs:17:13
    |
 LL |         baz(|| async{
    |             ^^
 note: required because it's used within this `async fn` body
-  --> $DIR/issue-70935-complex-spans.rs:9:67
+  --> $DIR/issue-70935-complex-spans.rs:10:67
    |
 LL |   async fn baz<T>(_c: impl FnMut() -> T) where T: Future<Output=()> {
    |  ___________________________________________________________________^
 LL | | }
    | |_^
-   = note: required because it captures the following types: `ResumeTy`, `impl for<'r, 's, 't0> Future<Output = ()>`, `()`
+   = note: required because it captures the following types: `ResumeTy`, `impl for<'a, 'b, 'c> Future<Output = ()>`, `()`
 note: required because it's used within this `async` block
-  --> $DIR/issue-70935-complex-spans.rs:15:16
+  --> $DIR/issue-70935-complex-spans.rs:16:16
    |
 LL |       async move {
    |  ________________^
diff --git a/src/test/ui/async-await/issue-70935-complex-spans.normal.stderr b/src/test/ui/async-await/issue-70935-complex-spans.no_drop_tracking.stderr
similarity index 81%
rename from src/test/ui/async-await/issue-70935-complex-spans.normal.stderr
rename to src/test/ui/async-await/issue-70935-complex-spans.no_drop_tracking.stderr
index 2b81b400099f..34b31198e4f6 100644
--- a/src/test/ui/async-await/issue-70935-complex-spans.normal.stderr
+++ b/src/test/ui/async-await/issue-70935-complex-spans.no_drop_tracking.stderr
@@ -1,12 +1,12 @@
 error: future cannot be sent between threads safely
-  --> $DIR/issue-70935-complex-spans.rs:12:45
+  --> $DIR/issue-70935-complex-spans.rs:13:45
    |
 LL | fn foo(tx: std::sync::mpsc::Sender<i32>) -> impl Future + Send {
    |                                             ^^^^^^^^^^^^^^^^^^ future created by async block is not `Send`
    |
    = help: the trait `Sync` is not implemented for `Sender<i32>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/issue-70935-complex-spans.rs:18:11
+  --> $DIR/issue-70935-complex-spans.rs:19:11
    |
 LL |           baz(|| async{
    |  _____________-
@@ -14,9 +14,9 @@ LL | |             foo(tx.clone());
 LL | |         }).await;
    | |         - ^^^^^^ await occurs here, with the value maybe used later
    | |_________|
-   |           has type `[closure@$DIR/issue-70935-complex-spans.rs:16:13: 16:15]` which is not `Send`
+   |           has type `[closure@$DIR/issue-70935-complex-spans.rs:17:13: 17:15]` which is not `Send`
 note: the value is later dropped here
-  --> $DIR/issue-70935-complex-spans.rs:18:17
+  --> $DIR/issue-70935-complex-spans.rs:19:17
    |
 LL |         }).await;
    |                 ^
diff --git a/src/test/ui/async-await/issue-70935-complex-spans.rs b/src/test/ui/async-await/issue-70935-complex-spans.rs
index 48847cdf974b..b6d17f93a667 100644
--- a/src/test/ui/async-await/issue-70935-complex-spans.rs
+++ b/src/test/ui/async-await/issue-70935-complex-spans.rs
@@ -1,5 +1,6 @@
 // edition:2018
-// revisions: normal drop_tracking
+// revisions: no_drop_tracking drop_tracking
+// [no_drop_tracking]compile-flags:-Zdrop-tracking=no
 // [drop_tracking]compile-flags:-Zdrop-tracking
 // #70935: Check if we do not emit snippet
 // with newlines which lead complex diagnostics.
@@ -10,7 +11,7 @@ async fn baz<T>(_c: impl FnMut() -> T) where T: Future<Output=()> {
 }
 
 fn foo(tx: std::sync::mpsc::Sender<i32>) -> impl Future + Send {
-    //[normal]~^ ERROR future cannot be sent between threads safely
+    //[no_drop_tracking]~^ ERROR future cannot be sent between threads safely
     //[drop_tracking]~^^ ERROR `Sender<i32>` cannot be shared between threads
     async move {
         baz(|| async{
diff --git a/src/test/ui/async-await/issue-73137.rs b/src/test/ui/async-await/issue-73137.rs
index c43ce2cadba0..dcbe7765a9e1 100644
--- a/src/test/ui/async-await/issue-73137.rs
+++ b/src/test/ui/async-await/issue-73137.rs
@@ -2,6 +2,9 @@
 
 // run-pass
 // edition:2018
+// revisions: normal drop-tracking
+// [normal]compile-flags: -Zdrop-tracking=no
+// [drop-tracking]compile-flags: -Zdrop-tracking
 
 #![allow(dead_code)]
 use std::future::Future;
diff --git a/src/test/ui/async-await/issues/issue-62009-1.stderr b/src/test/ui/async-await/issues/issue-62009-1.stderr
index fb9dee11f2a0..222afb2c7b2b 100644
--- a/src/test/ui/async-await/issues/issue-62009-1.stderr
+++ b/src/test/ui/async-await/issues/issue-62009-1.stderr
@@ -28,16 +28,14 @@ error[E0277]: `[closure@$DIR/issue-62009-1.rs:12:6: 12:9]` is not a future
   --> $DIR/issue-62009-1.rs:12:15
    |
 LL |     (|_| 2333).await;
-   |               ^^^^^^ `[closure@$DIR/issue-62009-1.rs:12:6: 12:9]` is not a future
+   |               ^^^^^^
+   |               |
+   |               `[closure@$DIR/issue-62009-1.rs:12:6: 12:9]` is not a future
+   |               help: remove the `.await`
    |
-   = help: the trait `Future` is not implemented for `[closure@$DIR/issue-62009-1.rs:12:6: 12:9]`
+   = help: the trait `Future` is not implemented for closure `[closure@$DIR/issue-62009-1.rs:12:6: 12:9]`
    = note: [closure@$DIR/issue-62009-1.rs:12:6: 12:9] must be a future or must implement `IntoFuture` to be awaited
    = note: required for `[closure@$DIR/issue-62009-1.rs:12:6: 12:9]` to implement `IntoFuture`
-help: remove the `.await`
-   |
-LL -     (|_| 2333).await;
-LL +     (|_| 2333);
-   |
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-panic.rs b/src/test/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-panic.rs
index 5e71229beb5f..b4ea4c9f6866 100644
--- a/src/test/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-panic.rs
+++ b/src/test/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-panic.rs
@@ -6,7 +6,6 @@
 // error-pattern: thread 'main' panicked at '`async fn` resumed after panicking'
 // edition:2018
 // ignore-wasm no panic or subprocess support
-// ignore-emscripten no panic or subprocess support
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr b/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.no_drop_tracking.stderr
similarity index 82%
rename from src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr
rename to src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.no_drop_tracking.stderr
index 99e960f5d0f2..a723503776b9 100644
--- a/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr
+++ b/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.no_drop_tracking.stderr
@@ -1,5 +1,5 @@
 error: future cannot be sent between threads safely
-  --> $DIR/issue-65436-raw-ptr-not-send.rs:12:17
+  --> $DIR/issue-65436-raw-ptr-not-send.rs:16:17
    |
 LL |       assert_send(async {
    |  _________________^
@@ -10,24 +10,24 @@ LL | |     })
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `*const u8`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/issue-65436-raw-ptr-not-send.rs:14:35
+  --> $DIR/issue-65436-raw-ptr-not-send.rs:18:35
    |
 LL |         bar(Foo(std::ptr::null())).await;
    |                 ----------------  ^^^^^^ await occurs here, with `std::ptr::null()` maybe used later
    |                 |
    |                 has type `*const u8` which is not `Send`
 note: `std::ptr::null()` is later dropped here
-  --> $DIR/issue-65436-raw-ptr-not-send.rs:14:41
+  --> $DIR/issue-65436-raw-ptr-not-send.rs:18:41
    |
 LL |         bar(Foo(std::ptr::null())).await;
    |                                         ^
 help: consider moving this into a `let` binding to create a shorter lived borrow
-  --> $DIR/issue-65436-raw-ptr-not-send.rs:14:13
+  --> $DIR/issue-65436-raw-ptr-not-send.rs:18:13
    |
 LL |         bar(Foo(std::ptr::null())).await;
    |             ^^^^^^^^^^^^^^^^^^^^^
 note: required by a bound in `assert_send`
-  --> $DIR/issue-65436-raw-ptr-not-send.rs:9:19
+  --> $DIR/issue-65436-raw-ptr-not-send.rs:13:19
    |
 LL | fn assert_send<T: Send>(_: T) {}
    |                   ^^^^ required by this bound in `assert_send`
diff --git a/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.rs b/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.rs
index 3a814b47517b..91edbc10dc0d 100644
--- a/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.rs
+++ b/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.rs
@@ -1,4 +1,8 @@
 // edition:2018
+// revisions: no_drop_tracking drop_tracking
+// [drop_tracking] check-pass
+// [drop_tracking] compile-flags: -Zdrop-tracking=yes
+// [no_drop_tracking] compile-flags: -Zdrop-tracking=no
 
 struct Foo(*const u8);
 
@@ -10,7 +14,7 @@ fn assert_send<T: Send>(_: T) {}
 
 fn main() {
     assert_send(async {
-    //~^ ERROR future cannot be sent between threads safely
+        //[no_drop_tracking]~^ ERROR future cannot be sent between threads safely
         bar(Foo(std::ptr::null())).await;
     })
 }
diff --git a/src/test/ui/async-await/issues/issue-95307.stderr b/src/test/ui/async-await/issues/issue-95307.stderr
index 29aebb719d66..a497cebe3c3d 100644
--- a/src/test/ui/async-await/issues/issue-95307.stderr
+++ b/src/test/ui/async-await/issues/issue-95307.stderr
@@ -8,6 +8,8 @@ LL |     async fn new() -> [u8; _];
    |
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
 error: in expressions, `_` can only be used on the left-hand side of an assignment
   --> $DIR/issue-95307.rs:7:28
diff --git a/src/test/ui/async-await/partial-drop-partial-reinit.drop_tracking.stderr b/src/test/ui/async-await/partial-drop-partial-reinit.drop_tracking.stderr
new file mode 100644
index 000000000000..17b4ef7bdc67
--- /dev/null
+++ b/src/test/ui/async-await/partial-drop-partial-reinit.drop_tracking.stderr
@@ -0,0 +1,35 @@
+error[E0277]: `NotSend` cannot be sent between threads safely
+  --> $DIR/partial-drop-partial-reinit.rs:9:16
+   |
+LL |     gimme_send(foo());
+   |     ---------- ^^^^^ `NotSend` cannot be sent between threads safely
+   |     |
+   |     required by a bound introduced by this call
+...
+LL | async fn foo() {
+   |                - within this `impl Future<Output = ()>`
+   |
+   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `NotSend`
+   = note: required because it appears within the type `(NotSend,)`
+   = note: required because it captures the following types: `ResumeTy`, `(NotSend,)`, `()`, `impl Future<Output = ()>`
+note: required because it's used within this `async fn` body
+  --> $DIR/partial-drop-partial-reinit.rs:31:16
+   |
+LL |   async fn foo() {
+   |  ________________^
+LL | |
+LL | |
+LL | |     let mut x = (NotSend {},);
+...  |
+LL | |     bar().await;
+LL | | }
+   | |_^
+note: required by a bound in `gimme_send`
+  --> $DIR/partial-drop-partial-reinit.rs:17:18
+   |
+LL | fn gimme_send<T: Send>(t: T) {
+   |                  ^^^^ required by this bound in `gimme_send`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/async-await/partial-drop-partial-reinit.stderr b/src/test/ui/async-await/partial-drop-partial-reinit.no_drop_tracking.stderr
similarity index 88%
rename from src/test/ui/async-await/partial-drop-partial-reinit.stderr
rename to src/test/ui/async-await/partial-drop-partial-reinit.no_drop_tracking.stderr
index 05f5358340a9..34d8a159f106 100644
--- a/src/test/ui/async-await/partial-drop-partial-reinit.stderr
+++ b/src/test/ui/async-await/partial-drop-partial-reinit.no_drop_tracking.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `NotSend` cannot be sent between threads safely
-  --> $DIR/partial-drop-partial-reinit.rs:6:16
+  --> $DIR/partial-drop-partial-reinit.rs:9:16
    |
 LL |     gimme_send(foo());
    |     ---------- ^^^^^ `NotSend` cannot be sent between threads safely
@@ -13,7 +13,7 @@ LL | async fn foo() {
    = note: required because it appears within the type `(NotSend,)`
    = note: required because it captures the following types: `ResumeTy`, `(NotSend,)`, `impl Future<Output = ()>`, `()`
 note: required because it's used within this `async fn` body
-  --> $DIR/partial-drop-partial-reinit.rs:28:16
+  --> $DIR/partial-drop-partial-reinit.rs:31:16
    |
 LL |   async fn foo() {
    |  ________________^
@@ -25,7 +25,7 @@ LL | |     bar().await;
 LL | | }
    | |_^
 note: required by a bound in `gimme_send`
-  --> $DIR/partial-drop-partial-reinit.rs:14:18
+  --> $DIR/partial-drop-partial-reinit.rs:17:18
    |
 LL | fn gimme_send<T: Send>(t: T) {
    |                  ^^^^ required by this bound in `gimme_send`
diff --git a/src/test/ui/async-await/partial-drop-partial-reinit.rs b/src/test/ui/async-await/partial-drop-partial-reinit.rs
index fe0fce7afd9f..7d097e72fb49 100644
--- a/src/test/ui/async-await/partial-drop-partial-reinit.rs
+++ b/src/test/ui/async-await/partial-drop-partial-reinit.rs
@@ -1,4 +1,7 @@
 // edition:2021
+// revisions: no_drop_tracking drop_tracking
+// [drop_tracking] compile-flags: -Zdrop-tracking=yes
+// [no_drop_tracking] compile-flags: -Zdrop-tracking=no
 #![feature(negative_impls)]
 #![allow(unused)]
 
@@ -12,8 +15,8 @@ fn main() {
 }
 
 fn gimme_send<T: Send>(t: T) {
-//~^ NOTE required by this bound
-//~| NOTE required by a bound
+    //~^ NOTE required by this bound
+    //~| NOTE required by a bound
     drop(t);
 }
 
@@ -26,8 +29,8 @@ impl Drop for NotSend {
 impl !Send for NotSend {}
 
 async fn foo() {
-//~^ NOTE used within this `async fn` body
-//~| NOTE within this `impl Future
+    //~^ NOTE used within this `async fn` body
+    //~| NOTE within this `impl Future
     let mut x = (NotSend {},);
     drop(x.0);
     x.0 = NotSend {};
diff --git a/src/test/ui/attributes/collapse-debuginfo-invalid.rs b/src/test/ui/attributes/collapse-debuginfo-invalid.rs
new file mode 100644
index 000000000000..42d8982c1186
--- /dev/null
+++ b/src/test/ui/attributes/collapse-debuginfo-invalid.rs
@@ -0,0 +1,110 @@
+#![feature(collapse_debuginfo)]
+#![feature(stmt_expr_attributes)]
+#![feature(type_alias_impl_trait)]
+#![no_std]
+
+// Test that the `#[collapse_debuginfo]` attribute can only be used on macro definitions.
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+extern crate std;
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+use std::collections::HashMap;
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+static FOO: u32 = 3;
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+const BAR: u32 = 3;
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+fn foo() {
+    let _ = #[collapse_debuginfo] || { };
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    let _ = 3;
+    let _ = #[collapse_debuginfo] 3;
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    match (3, 4) {
+        #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+        _ => (),
+    }
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+mod bar {
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+type Map = HashMap<u32, u32>;
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+enum Foo {
+    #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    Variant,
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+struct Bar {
+    #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    field: u32,
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+union Qux {
+    a: u32,
+    b: u16
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+trait Foobar {
+    #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    type Bar;
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+type AFoobar = impl Foobar;
+
+impl Foobar for Bar {
+    type Bar = u32;
+}
+
+fn constraining() -> AFoobar {
+    Bar { field: 3 }
+}
+
+#[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+impl Bar {
+    #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    const FOO: u32 = 3;
+
+    #[collapse_debuginfo]
+//~^ ERROR `collapse_debuginfo` attribute should be applied to macro definitions
+    fn bar(&self) {}
+}
+
+#[collapse_debuginfo]
+macro_rules! finally {
+    ($e:expr) => { $e }
+}
+
+fn main() {}
diff --git a/src/test/ui/attributes/collapse-debuginfo-invalid.stderr b/src/test/ui/attributes/collapse-debuginfo-invalid.stderr
new file mode 100644
index 000000000000..01c476091082
--- /dev/null
+++ b/src/test/ui/attributes/collapse-debuginfo-invalid.stderr
@@ -0,0 +1,222 @@
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:8:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | extern crate std;
+   | ----------------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:12:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | use std::collections::HashMap;
+   | ------------------------------ not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:16:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | static FOO: u32 = 3;
+   | -------------------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:20:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | const BAR: u32 = 3;
+   | ------------------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:24:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / fn foo() {
+LL | |     let _ = #[collapse_debuginfo] || { };
+LL | |
+LL | |     #[collapse_debuginfo]
+...  |
+LL | |     }
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:27:13
+   |
+LL |     let _ = #[collapse_debuginfo] || { };
+   |             ^^^^^^^^^^^^^^^^^^^^^ ------ not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:29:5
+   |
+LL |     #[collapse_debuginfo]
+   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |     let _ = 3;
+   |     ---------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:32:13
+   |
+LL |     let _ = #[collapse_debuginfo] 3;
+   |             ^^^^^^^^^^^^^^^^^^^^^ - not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:35:9
+   |
+LL |         #[collapse_debuginfo]
+   |         ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |         _ => (),
+   |         ------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:41:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / mod bar {
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:46:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | type Map = HashMap<u32, u32>;
+   | ----------------------------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:50:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / enum Foo {
+LL | |     #[collapse_debuginfo]
+LL | |
+LL | |     Variant,
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:53:5
+   |
+LL |     #[collapse_debuginfo]
+   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |     Variant,
+   |     ------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:58:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / struct Bar {
+LL | |     #[collapse_debuginfo]
+LL | |
+LL | |     field: u32,
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:61:5
+   |
+LL |     #[collapse_debuginfo]
+   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |     field: u32,
+   |     ---------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:66:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / union Qux {
+LL | |     a: u32,
+LL | |     b: u16
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:73:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / trait Foobar {
+LL | |     #[collapse_debuginfo]
+LL | |
+LL | |     type Bar;
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:81:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | type AFoobar = impl Foobar;
+   | --------------------------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:93:1
+   |
+LL |   #[collapse_debuginfo]
+   |   ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | / impl Bar {
+LL | |     #[collapse_debuginfo]
+LL | |
+LL | |     const FOO: u32 = 3;
+...  |
+LL | |     fn bar(&self) {}
+LL | | }
+   | |_- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:76:5
+   |
+LL |     #[collapse_debuginfo]
+   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |     type Bar;
+   |     --------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:96:5
+   |
+LL |     #[collapse_debuginfo]
+   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |     const FOO: u32 = 3;
+   |     ------------------- not a macro definition
+
+error: `collapse_debuginfo` attribute should be applied to macro definitions
+  --> $DIR/collapse-debuginfo-invalid.rs:100:5
+   |
+LL |     #[collapse_debuginfo]
+   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL |     fn bar(&self) {}
+   |     ---------------- not a macro definition
+
+error: aborting due to 22 previous errors
+
diff --git a/src/test/ui/attributes/issue-100631.rs b/src/test/ui/attributes/issue-100631.rs
new file mode 100644
index 000000000000..0fefcf83fd51
--- /dev/null
+++ b/src/test/ui/attributes/issue-100631.rs
@@ -0,0 +1,8 @@
+// issue #100631, make sure `TyCtxt::get_attr` only called by case that compiler
+// can reasonably deal with multiple attributes.
+// `repr` will use `TyCtxt::get_attrs` since it's `DuplicatesOk`.
+#[repr(C)] //~ ERROR: unsupported representation for zero-variant enum [E0084]
+#[repr(C)]
+enum Foo {}
+
+fn main() {}
diff --git a/src/test/ui/attributes/issue-100631.stderr b/src/test/ui/attributes/issue-100631.stderr
new file mode 100644
index 000000000000..caa5351ddc7a
--- /dev/null
+++ b/src/test/ui/attributes/issue-100631.stderr
@@ -0,0 +1,12 @@
+error[E0084]: unsupported representation for zero-variant enum
+  --> $DIR/issue-100631.rs:4:1
+   |
+LL | #[repr(C)]
+   | ^^^^^^^^^^
+LL | #[repr(C)]
+LL | enum Foo {}
+   | -------- zero-variant enum
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0084`.
diff --git a/src/test/ui/attributes/unix_sigpipe/auxiliary/sigpipe-utils.rs b/src/test/ui/attributes/unix_sigpipe/auxiliary/sigpipe-utils.rs
new file mode 100644
index 000000000000..e8b4fe7ae523
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/auxiliary/sigpipe-utils.rs
@@ -0,0 +1,31 @@
+#![feature(rustc_private)]
+extern crate libc;
+
+/// So tests don't have to bring libc in scope themselves
+pub enum SignalHandler {
+    Ignore,
+    Default,
+}
+
+/// Helper to assert that [`libc::SIGPIPE`] has the expected signal handler.
+pub fn assert_sigpipe_handler(expected_handler: SignalHandler) {
+    #[cfg(unix)]
+    #[cfg(not(any(
+        target_os = "emscripten",
+        target_os = "fuchsia",
+        target_os = "horizon",
+        target_os = "android",
+    )))]
+    {
+        let prev = unsafe { libc::signal(libc::SIGPIPE, libc::SIG_IGN) };
+
+        let expected = match expected_handler {
+            SignalHandler::Ignore => libc::SIG_IGN,
+            SignalHandler::Default => libc::SIG_DFL,
+        };
+        assert_eq!(prev, expected);
+
+        // Unlikely to matter, but restore the old value anyway
+        unsafe { libc::signal(libc::SIGPIPE, prev); };
+    }
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-crate.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-crate.rs
new file mode 100644
index 000000000000..d6d020c52b28
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-crate.rs
@@ -0,0 +1,4 @@
+#![feature(unix_sigpipe)]
+#![unix_sigpipe = "inherit"] //~ error: `unix_sigpipe` attribute cannot be used at crate level
+
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-crate.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-crate.stderr
new file mode 100644
index 000000000000..a1fb4d6787ce
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-crate.stderr
@@ -0,0 +1,13 @@
+error: `unix_sigpipe` attribute cannot be used at crate level
+  --> $DIR/unix_sigpipe-crate.rs:2:1
+   |
+LL | #![unix_sigpipe = "inherit"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[unix_sigpipe = "inherit"]
+   | ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.rs
new file mode 100644
index 000000000000..294cb38526bd
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.rs
@@ -0,0 +1,5 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "sig_ign"]
+#[unix_sigpipe = "inherit"] //~ error: multiple `unix_sigpipe` attributes
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.stderr
new file mode 100644
index 000000000000..2362c17a0904
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.stderr
@@ -0,0 +1,14 @@
+error: multiple `unix_sigpipe` attributes
+  --> $DIR/unix_sigpipe-duplicates.rs:4:1
+   |
+LL | #[unix_sigpipe = "inherit"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+note: attribute also specified here
+  --> $DIR/unix_sigpipe-duplicates.rs:3:1
+   |
+LL | #[unix_sigpipe = "sig_ign"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-error.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-error.rs
new file mode 100644
index 000000000000..0a42a5b5ef16
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-error.rs
@@ -0,0 +1,13 @@
+// run-pass
+// aux-build:sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "sig_ign"]
+fn main() {
+    extern crate sigpipe_utils;
+
+    // #[unix_sigpipe = "sig_ign"] is active, so the legacy behavior of ignoring
+    // SIGPIPE shall be in effect
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Ignore);
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs
new file mode 100644
index 000000000000..4f864807752c
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-inherit.rs
@@ -0,0 +1,14 @@
+// run-pass
+// aux-build:sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "inherit"]
+fn main() {
+    extern crate sigpipe_utils;
+
+    // #[unix_sigpipe = "inherit"] is active, so SIGPIPE shall NOT be ignored,
+    // instead the default handler shall be installed. (We assume that the
+    // process that runs these tests have the default handler.)
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Default);
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-list.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-list.rs
new file mode 100644
index 000000000000..b5ebc07a0433
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-list.rs
@@ -0,0 +1,4 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe(inherit)] //~ error: malformed `unix_sigpipe` attribute input
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-list.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-list.stderr
new file mode 100644
index 000000000000..59a87e139181
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-list.stderr
@@ -0,0 +1,15 @@
+error: malformed `unix_sigpipe` attribute input
+  --> $DIR/unix_sigpipe-list.rs:3:1
+   |
+LL | #[unix_sigpipe(inherit)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: the following are the possible correct uses
+   |
+LL | #[unix_sigpipe = "inherit|sig_ign|sig_dfl"]
+   | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+LL | #[unix_sigpipe]
+   | ~~~~~~~~~~~~~~~
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-main-fn.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-main-fn.rs
new file mode 100644
index 000000000000..cde6719fc9ce
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-main-fn.rs
@@ -0,0 +1,6 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "inherit"] //~ error: `unix_sigpipe` attribute can only be used on `fn main()`
+fn f() {}
+
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-main-fn.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-main-fn.stderr
new file mode 100644
index 000000000000..c4b81118c9f0
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-main-fn.stderr
@@ -0,0 +1,8 @@
+error: `unix_sigpipe` attribute can only be used on `fn main()`
+  --> $DIR/unix_sigpipe-non-main-fn.rs:3:1
+   |
+LL | #[unix_sigpipe = "inherit"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-root-main.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-root-main.rs
new file mode 100644
index 000000000000..16f7276398e2
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-root-main.rs
@@ -0,0 +1,8 @@
+#![feature(unix_sigpipe)]
+
+mod m {
+    #[unix_sigpipe = "inherit"] //~ error: `unix_sigpipe` attribute can only be used on root `fn main()`
+    fn main() {}
+}
+
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-root-main.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-root-main.stderr
new file mode 100644
index 000000000000..a04f605edc2e
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-non-root-main.stderr
@@ -0,0 +1,8 @@
+error: `unix_sigpipe` attribute can only be used on root `fn main()`
+  --> $DIR/unix_sigpipe-non-root-main.rs:4:5
+   |
+LL |     #[unix_sigpipe = "inherit"]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-not-used.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-not-used.rs
new file mode 100644
index 000000000000..100b4ce9f74f
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-not-used.rs
@@ -0,0 +1,9 @@
+// run-pass
+// aux-build:sigpipe-utils.rs
+
+fn main() {
+    extern crate sigpipe_utils;
+
+    // SIGPIPE shall be ignored since #[unix_sigpipe = "..."] is not used
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Ignore);
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-only-feature.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-only-feature.rs
new file mode 100644
index 000000000000..b5adc2e55721
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-only-feature.rs
@@ -0,0 +1,13 @@
+// run-pass
+// aux-build:sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+
+fn main() {
+    extern crate sigpipe_utils;
+
+    // Only #![feature(unix_sigpipe)] is enabled, not #[unix_sigpipe = "..."].
+    // This shall not change any behavior, so we still expect SIGPIPE to be
+    // ignored
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Ignore);
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-rustc_main.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-rustc_main.rs
new file mode 100644
index 000000000000..6befb9e95659
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-rustc_main.rs
@@ -0,0 +1,15 @@
+// run-pass
+// aux-build:sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+#![feature(rustc_attrs)]
+
+#[unix_sigpipe = "sig_dfl"]
+#[rustc_main]
+fn rustc_main() {
+    extern crate sigpipe_utils;
+
+    // #[unix_sigpipe = "sig_dfl"] is active, so SIGPIPE handler shall be
+    // SIG_DFL. Note that we have a #[rustc_main], but it should still work.
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Default);
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-sig_dfl.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-sig_dfl.rs
new file mode 100644
index 000000000000..238c0d57a68d
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-sig_dfl.rs
@@ -0,0 +1,13 @@
+// run-pass
+// aux-build:sigpipe-utils.rs
+
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "sig_dfl"]
+fn main() {
+    extern crate sigpipe_utils;
+
+    // #[unix_sigpipe = "sig_dfl"] is active, so SIGPIPE shall NOT be ignored, instead
+    // the default handler shall be installed
+    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Default);
+}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-start.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-start.rs
new file mode 100644
index 000000000000..64fd5ec4f0ed
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-start.rs
@@ -0,0 +1,6 @@
+#![feature(start)]
+#![feature(unix_sigpipe)]
+
+#[start]
+#[unix_sigpipe = "inherit"] //~ error: `unix_sigpipe` attribute can only be used on `fn main()`
+fn custom_start(argc: isize, argv: *const *const u8) -> isize { 0 }
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-start.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-start.stderr
new file mode 100644
index 000000000000..2c9ce479b6ca
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-start.stderr
@@ -0,0 +1,8 @@
+error: `unix_sigpipe` attribute can only be used on `fn main()`
+  --> $DIR/unix_sigpipe-start.rs:5:1
+   |
+LL | #[unix_sigpipe = "inherit"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-struct.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-struct.rs
new file mode 100644
index 000000000000..a5e47cfebc89
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-struct.rs
@@ -0,0 +1,6 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "inherit"] //~ error: `unix_sigpipe` attribute can only be used on `fn main()`
+struct S;
+
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-struct.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-struct.stderr
new file mode 100644
index 000000000000..c56ee60bb2e6
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-struct.stderr
@@ -0,0 +1,8 @@
+error: `unix_sigpipe` attribute can only be used on `fn main()`
+  --> $DIR/unix_sigpipe-struct.rs:3:1
+   |
+LL | #[unix_sigpipe = "inherit"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-wrong.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-wrong.rs
new file mode 100644
index 000000000000..4ec25de00ec3
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-wrong.rs
@@ -0,0 +1,4 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "wrong"] //~ error: valid values for `#[unix_sigpipe = "..."]` are `inherit`, `sig_ign`, or `sig_dfl`
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-wrong.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-wrong.stderr
new file mode 100644
index 000000000000..a66e45aa2104
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe-wrong.stderr
@@ -0,0 +1,8 @@
+error: valid values for `#[unix_sigpipe = "..."]` are `inherit`, `sig_ign`, or `sig_dfl`
+  --> $DIR/unix_sigpipe-wrong.rs:3:1
+   |
+LL | #[unix_sigpipe = "wrong"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe.rs b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe.rs
new file mode 100644
index 000000000000..7bf1c7350c38
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe.rs
@@ -0,0 +1,4 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe] //~ error: valid values for `#[unix_sigpipe = "..."]` are `inherit`, `sig_ign`, or `sig_dfl`
+fn main() {}
diff --git a/src/test/ui/attributes/unix_sigpipe/unix_sigpipe.stderr b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe.stderr
new file mode 100644
index 000000000000..1b1eda825aae
--- /dev/null
+++ b/src/test/ui/attributes/unix_sigpipe/unix_sigpipe.stderr
@@ -0,0 +1,8 @@
+error: valid values for `#[unix_sigpipe = "..."]` are `inherit`, `sig_ign`, or `sig_dfl`
+  --> $DIR/unix_sigpipe.rs:3:1
+   |
+LL | #[unix_sigpipe]
+   | ^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/backtrace.rs b/src/test/ui/backtrace.rs
index e2ac43fffc9e..dd73dd9886a3 100644
--- a/src/test/ui/backtrace.rs
+++ b/src/test/ui/backtrace.rs
@@ -4,6 +4,7 @@
 // ignore-openbsd no support for libbacktrace without filename
 // ignore-sgx no processes
 // ignore-msvc see #62897 and `backtrace-debuginfo.rs` test
+// ignore-fuchsia Backtraces not symbolized
 // compile-flags:-g
 // compile-flags:-Cstrip=none
 
diff --git a/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs b/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
index 684172ca61cc..0450fe8abbd1 100644
--- a/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
+++ b/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
@@ -3,7 +3,6 @@
 // Check that partially moved from function parameters are dropped after the
 // named bindings that move from them.
 
-// ignore-wasm32-bare compiled with panic=abort by default
 
 use std::{panic, cell::RefCell};
 
diff --git a/src/test/ui/binop/binary-op-on-double-ref.stderr b/src/test/ui/binop/binary-op-on-double-ref.stderr
index 1651f70d5cde..34826d2f4bf7 100644
--- a/src/test/ui/binop/binary-op-on-double-ref.stderr
+++ b/src/test/ui/binop/binary-op-on-double-ref.stderr
@@ -6,7 +6,7 @@ LL |         x % 2 == 0
    |         |
    |         &&{integer}
    |
-help: `%` can be used on `{integer}`, you can dereference `x`
+help: `%` can be used on `&{integer}` if you dereference the left-hand side
    |
 LL |         *x % 2 == 0
    |         +
diff --git a/src/test/ui/binop/issue-77910-1.rs b/src/test/ui/binop/issue-77910-1.rs
index d786e3358598..95bbd6a60ec8 100644
--- a/src/test/ui/binop/issue-77910-1.rs
+++ b/src/test/ui/binop/issue-77910-1.rs
@@ -7,5 +7,5 @@ fn main() {
     // we shouldn't ice with the bound var here.
     assert_eq!(foo, y);
     //~^ ERROR binary operation `==` cannot be applied to type
-    //~| ERROR `for<'r> fn(&'r i32) -> &'r i32 {foo}` doesn't implement `Debug`
+    //~| ERROR `for<'a> fn(&'a i32) -> &'a i32 {foo}` doesn't implement `Debug`
 }
diff --git a/src/test/ui/binop/issue-77910-1.stderr b/src/test/ui/binop/issue-77910-1.stderr
index 68303b842088..9c7bf6228be6 100644
--- a/src/test/ui/binop/issue-77910-1.stderr
+++ b/src/test/ui/binop/issue-77910-1.stderr
@@ -1,24 +1,24 @@
-error[E0369]: binary operation `==` cannot be applied to type `for<'r> fn(&'r i32) -> &'r i32 {foo}`
+error[E0369]: binary operation `==` cannot be applied to type `for<'a> fn(&'a i32) -> &'a i32 {foo}`
   --> $DIR/issue-77910-1.rs:8:5
    |
 LL |     assert_eq!(foo, y);
    |     ^^^^^^^^^^^^^^^^^^
    |     |
-   |     for<'r> fn(&'r i32) -> &'r i32 {foo}
+   |     for<'a> fn(&'a i32) -> &'a i32 {foo}
    |     _
    |
    = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0277]: `for<'r> fn(&'r i32) -> &'r i32 {foo}` doesn't implement `Debug`
+error[E0277]: `for<'a> fn(&'a i32) -> &'a i32 {foo}` doesn't implement `Debug`
   --> $DIR/issue-77910-1.rs:8:5
    |
 LL | fn foo(s: &i32) -> &i32 {
    |    --- consider calling this function
 ...
 LL |     assert_eq!(foo, y);
-   |     ^^^^^^^^^^^^^^^^^^ `for<'r> fn(&'r i32) -> &'r i32 {foo}` cannot be formatted using `{:?}` because it doesn't implement `Debug`
+   |     ^^^^^^^^^^^^^^^^^^ `for<'a> fn(&'a i32) -> &'a i32 {foo}` cannot be formatted using `{:?}` because it doesn't implement `Debug`
    |
-   = help: the trait `Debug` is not implemented for `for<'r> fn(&'r i32) -> &'r i32 {foo}`
+   = help: the trait `Debug` is not implemented for fn item `for<'a> fn(&'a i32) -> &'a i32 {foo}`
    = help: use parentheses to call the function: `foo(s)`
    = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
diff --git a/src/test/ui/binop/issue-77910-2.stderr b/src/test/ui/binop/issue-77910-2.stderr
index a334bd856259..b3856b6ae168 100644
--- a/src/test/ui/binop/issue-77910-2.stderr
+++ b/src/test/ui/binop/issue-77910-2.stderr
@@ -1,10 +1,10 @@
-error[E0369]: binary operation `==` cannot be applied to type `for<'r> fn(&'r i32) -> &'r i32 {foo}`
+error[E0369]: binary operation `==` cannot be applied to type `for<'a> fn(&'a i32) -> &'a i32 {foo}`
   --> $DIR/issue-77910-2.rs:7:12
    |
 LL |     if foo == y {}
    |        --- ^^ - _
    |        |
-   |        for<'r> fn(&'r i32) -> &'r i32 {foo}
+   |        for<'a> fn(&'a i32) -> &'a i32 {foo}
    |
 help: use parentheses to call this function
    |
diff --git a/src/test/ui/borrowck/bindings-after-at-or-patterns-slice-patterns-box-patterns.stderr b/src/test/ui/borrowck/bindings-after-at-or-patterns-slice-patterns-box-patterns.stderr
index d4f81930843b..1fd1eb128511 100644
--- a/src/test/ui/borrowck/bindings-after-at-or-patterns-slice-patterns-box-patterns.stderr
+++ b/src/test/ui/borrowck/bindings-after-at-or-patterns-slice-patterns-box-patterns.stderr
@@ -23,7 +23,7 @@ LL | fn bindings_after_at_slice_patterns_move_binding(x: [String; 4]) {
    |                                                  - move occurs because `x` has type `[String; 4]`, which does not implement the `Copy` trait
 LL |     match x {
 LL |         a @ [.., _] => (),
-   |         ----------- value moved here
+   |         - value moved here
 ...
 LL |     &x;
    |     ^^ value borrowed here after move
@@ -32,7 +32,7 @@ error[E0502]: cannot borrow `x` as immutable because it is also borrowed as muta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:28:5
    |
 LL |         ref mut foo @ [.., _] => Some(foo),
-   |         --------------------- mutable borrow occurs here
+   |         ----------- mutable borrow occurs here
 ...
 LL |     &x;
    |     ^^ immutable borrow occurs here
@@ -44,7 +44,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:50:5
    |
 LL |         [ref foo @ .., ref bar] => Some(foo),
-   |          ------------ immutable borrow occurs here
+   |          ------- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -56,7 +56,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:62:5
    |
 LL |         ref foo @ [.., ref bar] => Some(foo),
-   |         ----------------------- immutable borrow occurs here
+   |         ------- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -71,7 +71,7 @@ LL | fn bindings_after_at_or_patterns_move(x: Option<Test>) {
    |                                       - move occurs because `x` has type `Option<Test>`, which does not implement the `Copy` trait
 LL |     match x {
 LL |         foo @ Some(Test::Foo | Test::Bar) => (),
-   |         ---------------------------------
+   |         ---
    |         |
    |         value moved here
    |         value moved here
@@ -83,7 +83,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:86:5
    |
 LL |         ref foo @ Some(Test::Foo | Test::Bar) => Some(foo),
-   |         ------------------------------------- immutable borrow occurs here
+   |         ------- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -95,7 +95,7 @@ error[E0502]: cannot borrow `x` as immutable because it is also borrowed as muta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:98:5
    |
 LL |         ref mut foo @ Some(Test::Foo | Test::Bar) => Some(foo),
-   |         ----------------------------------------- mutable borrow occurs here
+   |         ----------- mutable borrow occurs here
 ...
 LL |     &x;
    |     ^^ immutable borrow occurs here
@@ -107,7 +107,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:112:5
    |
 LL |         ref foo @ Some(box ref s) => Some(foo),
-   |         ------------------------- immutable borrow occurs here
+   |         ------- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -122,7 +122,7 @@ LL | fn bindings_after_at_slice_patterns_or_patterns_moves(x: [Option<Test>; 4])
    |                                                       - move occurs because `x` has type `[Option<Test>; 4]`, which does not implement the `Copy` trait
 LL |     match x {
 LL |         a @ [.., Some(Test::Foo | Test::Bar)] => (),
-   |         -------------------------------------
+   |         -
    |         |
    |         value moved here
    |         value moved here
@@ -134,7 +134,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:144:5
    |
 LL |         ref a @ [ref b @ .., Some(Test::Foo | Test::Bar)] => Some(a),
-   |         ------------------------------------------------- immutable borrow occurs here
+   |         ----- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -146,7 +146,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:156:5
    |
 LL |         ref a @ [ref b @ .., Some(Test::Foo | Test::Bar)] => Some(b),
-   |                  ---------- immutable borrow occurs here
+   |                  ----- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -158,7 +158,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:170:5
    |
 LL |         [_, ref a @ Some(box ref b), ..] => Some(a),
-   |             ----------------------- immutable borrow occurs here
+   |             ----- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -170,7 +170,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:186:5
    |
 LL |         [_, ref a @ Some(box Test::Foo | box Test::Bar), ..] => Some(a),
-   |             ------------------------------------------- immutable borrow occurs here
+   |             ----- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
@@ -182,7 +182,7 @@ error[E0502]: cannot borrow `x` as immutable because it is also borrowed as muta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:200:5
    |
 LL |         [_, ref mut a @ Some(box Test::Foo | box Test::Bar), ..] => Some(a),
-   |             ----------------------------------------------- mutable borrow occurs here
+   |             --------- mutable borrow occurs here
 ...
 LL |     &x;
    |     ^^ immutable borrow occurs here
@@ -194,7 +194,7 @@ error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immuta
   --> $DIR/bindings-after-at-or-patterns-slice-patterns-box-patterns.rs:214:5
    |
 LL |         ref a @ [_, ref b @ Some(box Test::Foo | box Test::Bar), ..] => Some(a),
-   |         ------------------------------------------------------------ immutable borrow occurs here
+   |         ----- immutable borrow occurs here
 ...
 LL |     &mut x;
    |     ^^^^^^ mutable borrow occurs here
diff --git a/src/test/ui/borrowck/borrowck-block-unint.stderr b/src/test/ui/borrowck/borrowck-block-unint.stderr
index e720db1c6961..f47921a97526 100644
--- a/src/test/ui/borrowck/borrowck-block-unint.stderr
+++ b/src/test/ui/borrowck/borrowck-block-unint.stderr
@@ -7,6 +7,11 @@ LL |     force(|| {
    |           ^^ `x` used here but it isn't initialized
 LL |         println!("{}", x);
    |                        - borrow occurs due to use in closure
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-break-uninit-2.stderr b/src/test/ui/borrowck/borrowck-break-uninit-2.stderr
index 91038b3adca9..ea93a8f409ce 100644
--- a/src/test/ui/borrowck/borrowck-break-uninit-2.stderr
+++ b/src/test/ui/borrowck/borrowck-break-uninit-2.stderr
@@ -8,6 +8,10 @@ LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-break-uninit.stderr b/src/test/ui/borrowck/borrowck-break-uninit.stderr
index 8d0c9582fda9..a7a8fc2ff837 100644
--- a/src/test/ui/borrowck/borrowck-break-uninit.stderr
+++ b/src/test/ui/borrowck/borrowck-break-uninit.stderr
@@ -8,6 +8,10 @@ LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-describe-lvalue.stderr b/src/test/ui/borrowck/borrowck-describe-lvalue.stderr
index cfcc62de4383..2c1b9c10d466 100644
--- a/src/test/ui/borrowck/borrowck-describe-lvalue.stderr
+++ b/src/test/ui/borrowck/borrowck-describe-lvalue.stderr
@@ -200,7 +200,7 @@ LL |         let x = &mut v;
    |                 ------ borrow of `v` occurs here
 LL |         match v {
 LL |             &[x @ ..] => println!("{:?}", x),
-   |               ^^^^^^ use of borrowed `v`
+   |               ^ use of borrowed `v`
 ...
 LL |         drop(x);
    |              - borrow later used here
@@ -212,7 +212,7 @@ LL |         let x = &mut v;
    |                 ------ borrow of `v` occurs here
 ...
 LL |             &[_, x @ ..] => println!("{:?}", x),
-   |                  ^^^^^^ use of borrowed `v`
+   |                  ^ use of borrowed `v`
 ...
 LL |         drop(x);
    |              - borrow later used here
@@ -224,7 +224,7 @@ LL |         let x = &mut v;
    |                 ------ borrow of `v` occurs here
 ...
 LL |             &[x @ .., _] => println!("{:?}", x),
-   |               ^^^^^^ use of borrowed `v`
+   |               ^ use of borrowed `v`
 ...
 LL |         drop(x);
    |              - borrow later used here
@@ -236,7 +236,7 @@ LL |         let x = &mut v;
    |                 ------ borrow of `v` occurs here
 ...
 LL |             &[_, x @ .., _] => println!("{:?}", x),
-   |                  ^^^^^^ use of borrowed `v`
+   |                  ^ use of borrowed `v`
 ...
 LL |         drop(x);
    |              - borrow later used here
diff --git a/src/test/ui/borrowck/borrowck-init-in-called-fn-expr.stderr b/src/test/ui/borrowck/borrowck-init-in-called-fn-expr.stderr
index e8a2fbc91ea6..1a22b5f0975c 100644
--- a/src/test/ui/borrowck/borrowck-init-in-called-fn-expr.stderr
+++ b/src/test/ui/borrowck/borrowck-init-in-called-fn-expr.stderr
@@ -5,6 +5,11 @@ LL |         let i: isize;
    |             - binding declared here but left uninitialized
 LL |         i
    |         ^ `i` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let i: isize = 0;
+   |                      +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-init-in-fn-expr.stderr b/src/test/ui/borrowck/borrowck-init-in-fn-expr.stderr
index 1e950d6a20de..f1b9b9aa7090 100644
--- a/src/test/ui/borrowck/borrowck-init-in-fn-expr.stderr
+++ b/src/test/ui/borrowck/borrowck-init-in-fn-expr.stderr
@@ -5,6 +5,11 @@ LL |         let i: isize;
    |             - binding declared here but left uninitialized
 LL |         i
    |         ^ `i` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let i: isize = 0;
+   |                      +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-init-in-fru.stderr b/src/test/ui/borrowck/borrowck-init-in-fru.stderr
index 83a3e3e0e3ae..39b28811a0c2 100644
--- a/src/test/ui/borrowck/borrowck-init-in-fru.stderr
+++ b/src/test/ui/borrowck/borrowck-init-in-fru.stderr
@@ -5,6 +5,11 @@ LL |     let mut origin: Point;
    |         ---------- binding declared here but left uninitialized
 LL |     origin = Point { x: 10, ..origin };
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^ `origin.y` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let mut origin: Point = todo!();
+   |                           +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-init-op-equal.stderr b/src/test/ui/borrowck/borrowck-init-op-equal.stderr
index 74704b2abfee..ef0fa6df4fb7 100644
--- a/src/test/ui/borrowck/borrowck-init-op-equal.stderr
+++ b/src/test/ui/borrowck/borrowck-init-op-equal.stderr
@@ -5,6 +5,11 @@ LL |     let v: isize;
    |         - binding declared here but left uninitialized
 LL |     v += 1;
    |     ^^^^^^ `v` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let v: isize = 0;
+   |                  +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-init-plus-equal.stderr b/src/test/ui/borrowck/borrowck-init-plus-equal.stderr
index 7542576d636b..cec053318364 100644
--- a/src/test/ui/borrowck/borrowck-init-plus-equal.stderr
+++ b/src/test/ui/borrowck/borrowck-init-plus-equal.stderr
@@ -5,6 +5,11 @@ LL |     let mut v: isize;
    |         ----- binding declared here but left uninitialized
 LL |     v = v + 1;
    |         ^ `v` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let mut v: isize = 0;
+   |                      +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-move-out-from-array-match.stderr b/src/test/ui/borrowck/borrowck-move-out-from-array-match.stderr
index 3249aae8f44a..346b82a26664 100644
--- a/src/test/ui/borrowck/borrowck-move-out-from-array-match.stderr
+++ b/src/test/ui/borrowck/borrowck-move-out-from-array-match.stderr
@@ -79,7 +79,7 @@ error[E0382]: use of moved value: `a[..].0`
   --> $DIR/borrowck-move-out-from-array-match.rs:89:11
    |
 LL |         [_y @ .., _, _] => {}
-   |          ------- value moved here
+   |          -- value moved here
 ...
 LL |         [(_x, _), _, _] => {}
    |           ^^ value used here after move
@@ -90,7 +90,7 @@ error[E0382]: use of moved value: `a[..].0`
   --> $DIR/borrowck-move-out-from-array-match.rs:99:15
    |
 LL |         [_, _, _y @ ..] => {}
-   |                ------- value moved here
+   |                -- value moved here
 ...
 LL |         [.., (_x, _)] => {}
    |               ^^ value used here after move
@@ -101,7 +101,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-match.rs:110:11
    |
 LL |         [x @ .., _] => {}
-   |          ------ value partially moved here
+   |          - value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
diff --git a/src/test/ui/borrowck/borrowck-move-out-from-array-no-overlap-match.stderr b/src/test/ui/borrowck/borrowck-move-out-from-array-no-overlap-match.stderr
index c198002265b7..6c6a25c251e7 100644
--- a/src/test/ui/borrowck/borrowck-move-out-from-array-no-overlap-match.stderr
+++ b/src/test/ui/borrowck/borrowck-move-out-from-array-no-overlap-match.stderr
@@ -68,7 +68,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-no-overlap-match.rs:85:11
    |
 LL |         [_, _y @ ..] => {}
-   |             ------- value partially moved here
+   |             -- value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
@@ -79,7 +79,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-no-overlap-match.rs:96:11
    |
 LL |         [_y @ .., _] => {}
-   |          ------- value partially moved here
+   |          -- value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
@@ -90,7 +90,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-no-overlap-match.rs:109:11
    |
 LL |         [x @ .., _, _] => {}
-   |          ------ value partially moved here
+   |          - value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
diff --git a/src/test/ui/borrowck/borrowck-move-out-from-array-use-match.stderr b/src/test/ui/borrowck/borrowck-move-out-from-array-use-match.stderr
index 8f2da9d203b0..77702e145df8 100644
--- a/src/test/ui/borrowck/borrowck-move-out-from-array-use-match.stderr
+++ b/src/test/ui/borrowck/borrowck-move-out-from-array-use-match.stderr
@@ -79,7 +79,7 @@ error[E0382]: borrow of moved value: `a[..]`
   --> $DIR/borrowck-move-out-from-array-use-match.rs:89:11
    |
 LL |         [_y @ .., _, _] => {}
-   |          ------- value moved here
+   |          -- value moved here
 ...
 LL |         [(ref _x, _), _, _] => {}
    |           ^^^^^^ value borrowed here after move
@@ -90,7 +90,7 @@ error[E0382]: borrow of moved value: `a[..]`
   --> $DIR/borrowck-move-out-from-array-use-match.rs:99:15
    |
 LL |         [_, _, _y @ ..] => {}
-   |                ------- value moved here
+   |                -- value moved here
 ...
 LL |         [.., (ref _x, _)] => {}
    |               ^^^^^^ value borrowed here after move
@@ -101,7 +101,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use-match.rs:110:11
    |
 LL |         [x @ .., _] => {}
-   |          ------ value partially moved here
+   |          - value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
@@ -134,7 +134,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use-match.rs:139:5
    |
 LL |         [_, _, _x @ ..] => {}
-   |                ------- value partially moved here
+   |                -- value partially moved here
 LL |     }
 LL |     a[0] = Default::default();
    |     ^^^^ value used here after partial move
@@ -145,7 +145,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use-match.rs:147:5
    |
 LL |         [_, _, _x @ ..] => {}
-   |                ------- value partially moved here
+   |                -- value partially moved here
 LL |     }
 LL |     a[0].1 = Default::default();
    |     ^^^^ value used here after partial move
diff --git a/src/test/ui/borrowck/borrowck-move-out-from-array-use-no-overlap-match.stderr b/src/test/ui/borrowck/borrowck-move-out-from-array-use-no-overlap-match.stderr
index 4b27f03dc458..6cc2c2f7a984 100644
--- a/src/test/ui/borrowck/borrowck-move-out-from-array-use-no-overlap-match.stderr
+++ b/src/test/ui/borrowck/borrowck-move-out-from-array-use-no-overlap-match.stderr
@@ -68,7 +68,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use-no-overlap-match.rs:85:11
    |
 LL |         [_, _y @ ..] => {}
-   |             ------- value partially moved here
+   |             -- value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
@@ -79,7 +79,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use-no-overlap-match.rs:96:11
    |
 LL |         [_y @ .., _] => {}
-   |          ------- value partially moved here
+   |          -- value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
@@ -90,7 +90,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use-no-overlap-match.rs:109:11
    |
 LL |         [x @ .., _, _] => {}
-   |          ------ value partially moved here
+   |          - value partially moved here
 LL |     }
 LL |     match a {
    |           ^ value used here after partial move
diff --git a/src/test/ui/borrowck/borrowck-move-out-from-array-use.stderr b/src/test/ui/borrowck/borrowck-move-out-from-array-use.stderr
index b0bad6e99788..9add7553afa7 100644
--- a/src/test/ui/borrowck/borrowck-move-out-from-array-use.stderr
+++ b/src/test/ui/borrowck/borrowck-move-out-from-array-use.stderr
@@ -34,7 +34,7 @@ error[E0382]: borrow of partially moved value: `a`
 LL |     let [_x, _, _] = a;
    |          -- value partially moved here
 LL |     let [ref _y @ .., _, _] = a;
-   |          ^^^^^^^^^^^ value borrowed here after partial move
+   |          ^^^^^^ value borrowed here after partial move
    |
    = note: partial move occurs because `a[..]` has type `(String, String)`, which does not implement the `Copy` trait
 
@@ -44,7 +44,7 @@ error[E0382]: borrow of partially moved value: `a`
 LL |     let [.., _x] = a;
    |              -- value partially moved here
 LL |     let [_, _, ref _y @ ..] = a;
-   |                ^^^^^^^^^^^ value borrowed here after partial move
+   |                ^^^^^^ value borrowed here after partial move
    |
    = note: partial move occurs because `a[..]` has type `(String, String)`, which does not implement the `Copy` trait
 
@@ -54,7 +54,7 @@ error[E0382]: borrow of partially moved value: `a`
 LL |     let [(_x, _), _, _] = a;
    |           -- value partially moved here
 LL |     let [ref _y @ .., _, _] = a;
-   |          ^^^^^^^^^^^ value borrowed here after partial move
+   |          ^^^^^^ value borrowed here after partial move
    |
    = note: partial move occurs because `a[..].0` has type `String`, which does not implement the `Copy` trait
 
@@ -64,7 +64,7 @@ error[E0382]: borrow of partially moved value: `a`
 LL |     let [.., (_x, _)] = a;
    |               -- value partially moved here
 LL |     let [_, _, ref _y @ ..] = a;
-   |                ^^^^^^^^^^^ value borrowed here after partial move
+   |                ^^^^^^ value borrowed here after partial move
    |
    = note: partial move occurs because `a[..].0` has type `String`, which does not implement the `Copy` trait
 
@@ -72,7 +72,7 @@ error[E0382]: borrow of moved value: `a[..]`
   --> $DIR/borrowck-move-out-from-array-use.rs:54:11
    |
 LL |     let [_y @ .., _, _] = a;
-   |          ------- value moved here
+   |          -- value moved here
 LL |     let [(ref _x, _), _, _] = a;
    |           ^^^^^^ value borrowed here after move
    |
@@ -82,7 +82,7 @@ error[E0382]: borrow of moved value: `a[..]`
   --> $DIR/borrowck-move-out-from-array-use.rs:60:15
    |
 LL |     let [_, _, _y @ ..] = a;
-   |                ------- value moved here
+   |                -- value moved here
 LL |     let [.., (ref _x, _)] = a;
    |               ^^^^^^ value borrowed here after move
    |
@@ -92,9 +92,9 @@ error[E0382]: borrow of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use.rs:68:13
    |
 LL |     let [x @ .., _] = a;
-   |          ------ value partially moved here
+   |          - value partially moved here
 LL |     let [_, ref _y @ ..] = a;
-   |             ^^^^^^^^^^^ value borrowed here after partial move
+   |             ^^^^^^ value borrowed here after partial move
    |
    = note: partial move occurs because `a[..]` has type `(String, String)`, which does not implement the `Copy` trait
 
@@ -122,7 +122,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use.rs:88:5
    |
 LL |     let [_, _, _x @ ..] = a;
-   |                ------- value partially moved here
+   |                -- value partially moved here
 LL |     a[0] = Default::default();
    |     ^^^^ value used here after partial move
    |
@@ -132,7 +132,7 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array-use.rs:94:5
    |
 LL |     let [_, _, _x @ ..] = a;
-   |                ------- value partially moved here
+   |                -- value partially moved here
 LL |     a[0].1 = Default::default();
    |     ^^^^ value used here after partial move
    |
diff --git a/src/test/ui/borrowck/borrowck-move-out-from-array.stderr b/src/test/ui/borrowck/borrowck-move-out-from-array.stderr
index 1fc2b292b84c..363effcfe532 100644
--- a/src/test/ui/borrowck/borrowck-move-out-from-array.stderr
+++ b/src/test/ui/borrowck/borrowck-move-out-from-array.stderr
@@ -34,7 +34,7 @@ error[E0382]: use of partially moved value: `a`
 LL |     let [_x, _, _] = a;
    |          -- value partially moved here
 LL |     let [_y @ .., _, _] = a;
-   |          ^^^^^^^ value used here after partial move
+   |          ^^ value used here after partial move
    |
    = note: partial move occurs because `a[..]` has type `(String, String)`, which does not implement the `Copy` trait
 
@@ -44,7 +44,7 @@ error[E0382]: use of partially moved value: `a`
 LL |     let [.., _x] = a;
    |              -- value partially moved here
 LL |     let [_, _, _y @ ..] = a;
-   |                ^^^^^^^ value used here after partial move
+   |                ^^ value used here after partial move
    |
    = note: partial move occurs because `a[..]` has type `(String, String)`, which does not implement the `Copy` trait
 
@@ -54,7 +54,7 @@ error[E0382]: use of partially moved value: `a`
 LL |     let [(_x, _), _, _] = a;
    |           -- value partially moved here
 LL |     let [_y @ .., _, _] = a;
-   |          ^^^^^^^ value used here after partial move
+   |          ^^ value used here after partial move
    |
    = note: partial move occurs because `a[..].0` has type `String`, which does not implement the `Copy` trait
 
@@ -64,7 +64,7 @@ error[E0382]: use of partially moved value: `a`
 LL |     let [.., (_x, _)] = a;
    |               -- value partially moved here
 LL |     let [_, _, _y @ ..] = a;
-   |                ^^^^^^^ value used here after partial move
+   |                ^^ value used here after partial move
    |
    = note: partial move occurs because `a[..].0` has type `String`, which does not implement the `Copy` trait
 
@@ -72,7 +72,7 @@ error[E0382]: use of moved value: `a[..].0`
   --> $DIR/borrowck-move-out-from-array.rs:54:11
    |
 LL |     let [_y @ .., _, _] = a;
-   |          ------- value moved here
+   |          -- value moved here
 LL |     let [(_x, _), _, _] = a;
    |           ^^ value used here after move
    |
@@ -82,7 +82,7 @@ error[E0382]: use of moved value: `a[..].0`
   --> $DIR/borrowck-move-out-from-array.rs:60:15
    |
 LL |     let [_, _, _y @ ..] = a;
-   |                ------- value moved here
+   |                -- value moved here
 LL |     let [.., (_x, _)] = a;
    |               ^^ value used here after move
    |
@@ -92,9 +92,9 @@ error[E0382]: use of partially moved value: `a`
   --> $DIR/borrowck-move-out-from-array.rs:68:13
    |
 LL |     let [x @ .., _] = a;
-   |          ------ value partially moved here
+   |          - value partially moved here
 LL |     let [_, _y @ ..] = a;
-   |             ^^^^^^^ value used here after partial move
+   |             ^^ value used here after partial move
    |
    = note: partial move occurs because `a[..]` has type `(String, String)`, which does not implement the `Copy` trait
 
diff --git a/src/test/ui/borrowck/borrowck-return.stderr b/src/test/ui/borrowck/borrowck-return.stderr
index 1c916e223175..9799357c9ca1 100644
--- a/src/test/ui/borrowck/borrowck-return.stderr
+++ b/src/test/ui/borrowck/borrowck-return.stderr
@@ -5,6 +5,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     return x;
    |            ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-array.stderr b/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-array.stderr
index b8ac7a3a4469..f4324110ccb8 100644
--- a/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-array.stderr
+++ b/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-array.stderr
@@ -57,7 +57,7 @@ error[E0502]: cannot borrow `s[..]` as mutable because it is also borrowed as im
 LL |     let [ref first, ref second, ..] = *s;
    |                     ---------- immutable borrow occurs here
 LL |     let [_, ref mut tail @ ..] = *s;
-   |             ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+   |             ^^^^^^^^^^^^ mutable borrow occurs here
 LL |     nop(&[first, second]);
    |                  ------ immutable borrow later used here
 
@@ -67,7 +67,7 @@ error[E0502]: cannot borrow `s[..]` as mutable because it is also borrowed as im
 LL |     let [.., ref second, ref first] = *s;
    |              ---------- immutable borrow occurs here
 LL |     let [ref mut tail @ .., _] = *s;
-   |          ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+   |          ^^^^^^^^^^^^ mutable borrow occurs here
 LL |     nop(&[first, second]);
    |                  ------ immutable borrow later used here
 
@@ -75,9 +75,9 @@ error[E0502]: cannot borrow `s[..]` as mutable because it is also borrowed as im
   --> $DIR/borrowck-slice-pattern-element-loan-array.rs:46:10
    |
 LL |     let [_,  ref s1 @ ..] = *s;
-   |              ----------- immutable borrow occurs here
+   |              ------ immutable borrow occurs here
 LL |     let [ref mut s2 @ .., _, _] = *s;
-   |          ^^^^^^^^^^^^^^^ mutable borrow occurs here
+   |          ^^^^^^^^^^ mutable borrow occurs here
 LL |     nop_subslice(s1);
    |                  -- immutable borrow later used here
 
diff --git a/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-slice.stderr b/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-slice.stderr
index d3388e071aa5..f9a63bd49dd5 100644
--- a/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-slice.stderr
+++ b/src/test/ui/borrowck/borrowck-slice-pattern-element-loan-slice.stderr
@@ -88,7 +88,7 @@ error[E0502]: cannot borrow `s[..]` as mutable because it is also borrowed as im
 LL |     if let [ref first, ref second, ..] = *s {
    |                        ---------- immutable borrow occurs here
 LL |         if let [_, ref mut tail @ ..] = *s {
-   |                    ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+   |                    ^^^^^^^^^^^^ mutable borrow occurs here
 LL |             nop(&[first, second]);
    |                          ------ immutable borrow later used here
 
@@ -98,7 +98,7 @@ error[E0502]: cannot borrow `s[..]` as mutable because it is also borrowed as im
 LL |     if let [.., ref second, ref first] = *s {
    |                 ---------- immutable borrow occurs here
 LL |         if let [ref mut tail @ .., _] = *s {
-   |                 ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
+   |                 ^^^^^^^^^^^^ mutable borrow occurs here
 LL |             nop(&[first, second]);
    |                          ------ immutable borrow later used here
 
@@ -106,9 +106,9 @@ error[E0502]: cannot borrow `s[..]` as mutable because it is also borrowed as im
   --> $DIR/borrowck-slice-pattern-element-loan-slice.rs:65:17
    |
 LL |     if let [_, _, _, ref s1 @ ..] = *s {
-   |                      ----------- immutable borrow occurs here
+   |                      ------ immutable borrow occurs here
 LL |         if let [ref mut s2 @ .., _, _, _] = *s {
-   |                 ^^^^^^^^^^^^^^^ mutable borrow occurs here
+   |                 ^^^^^^^^^^ mutable borrow occurs here
 LL |             nop_subslice(s1);
    |                          -- immutable borrow later used here
 
diff --git a/src/test/ui/borrowck/borrowck-storage-dead.stderr b/src/test/ui/borrowck/borrowck-storage-dead.stderr
index 2cea4392d6ad..3a413153acd1 100644
--- a/src/test/ui/borrowck/borrowck-storage-dead.stderr
+++ b/src/test/ui/borrowck/borrowck-storage-dead.stderr
@@ -5,6 +5,11 @@ LL |         let x: i32;
    |             - binding declared here but left uninitialized
 LL |         let _ = x + 1;
    |                 ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let x: i32 = 0;
+   |                    +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-uninit-after-item.stderr b/src/test/ui/borrowck/borrowck-uninit-after-item.stderr
index 588b1b0c9729..071598b42eec 100644
--- a/src/test/ui/borrowck/borrowck-uninit-after-item.stderr
+++ b/src/test/ui/borrowck/borrowck-uninit-after-item.stderr
@@ -6,6 +6,11 @@ LL |     let bar;
 LL |     fn baz(_x: isize) { }
 LL |     baz(bar);
    |         ^^^ `bar` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let bar = 0;
+   |             +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-uninit-field-access.stderr b/src/test/ui/borrowck/borrowck-uninit-field-access.stderr
index 6a38a7989197..f0f4ad704b7c 100644
--- a/src/test/ui/borrowck/borrowck-uninit-field-access.stderr
+++ b/src/test/ui/borrowck/borrowck-uninit-field-access.stderr
@@ -5,6 +5,11 @@ LL |     let mut a: Point;
    |         ----- binding declared here but left uninitialized
 LL |     let _ = a.x + 1;
    |             ^^^ `a.x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let mut a: Point = Default::default();
+   |                      ++++++++++++++++++++
 
 error[E0382]: use of moved value: `line1.origin`
   --> $DIR/borrowck-uninit-field-access.rs:25:13
diff --git a/src/test/ui/borrowck/borrowck-uninit-in-assignop.stderr b/src/test/ui/borrowck/borrowck-uninit-in-assignop.stderr
index 744cb14e662b..fdbb451bde4e 100644
--- a/src/test/ui/borrowck/borrowck-uninit-in-assignop.stderr
+++ b/src/test/ui/borrowck/borrowck-uninit-in-assignop.stderr
@@ -5,6 +5,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x += 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:9:5
@@ -13,6 +18,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x -= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:12:5
@@ -21,6 +31,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x *= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:15:5
@@ -29,6 +44,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x /= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:18:5
@@ -37,6 +57,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x %= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:21:5
@@ -45,6 +70,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x ^= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:24:5
@@ -53,6 +83,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x &= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:27:5
@@ -61,6 +96,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x |= 1;
    |     ^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:30:5
@@ -69,6 +109,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x <<= 1;
    |     ^^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-in-assignop.rs:33:5
@@ -77,6 +122,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     x >>= 1;
    |     ^^^^^^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error: aborting due to 10 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-uninit-ref-chain.stderr b/src/test/ui/borrowck/borrowck-uninit-ref-chain.stderr
index c486cb6dd0cd..73fded7545cc 100644
--- a/src/test/ui/borrowck/borrowck-uninit-ref-chain.stderr
+++ b/src/test/ui/borrowck/borrowck-uninit-ref-chain.stderr
@@ -5,6 +5,11 @@ LL |     let x: &&Box<i32>;
    |         - binding declared here but left uninitialized
 LL |     let _y = &**x;
    |              ^^^^ `**x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: &&Box<i32> = todo!();
+   |                       +++++++++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-ref-chain.rs:11:14
@@ -13,6 +18,11 @@ LL |     let x: &&S<i32, i32>;
    |         - binding declared here but left uninitialized
 LL |     let _y = &**x;
    |              ^^^^ `**x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: &&S<i32, i32> = todo!();
+   |                          +++++++++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/borrowck-uninit-ref-chain.rs:14:14
@@ -21,6 +31,11 @@ LL |     let x: &&i32;
    |         - binding declared here but left uninitialized
 LL |     let _y = &**x;
    |              ^^^^ `**x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: &&i32 = todo!();
+   |                  +++++++++
 
 error[E0381]: partially assigned binding `a` isn't fully initialized
   --> $DIR/borrowck-uninit-ref-chain.rs:18:5
diff --git a/src/test/ui/borrowck/borrowck-uninit.stderr b/src/test/ui/borrowck/borrowck-uninit.stderr
index d5566691a820..eeafc4ce191c 100644
--- a/src/test/ui/borrowck/borrowck-uninit.stderr
+++ b/src/test/ui/borrowck/borrowck-uninit.stderr
@@ -5,6 +5,11 @@ LL |     let x: isize;
    |         - binding declared here but left uninitialized
 LL |     foo(x);
    |         ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: isize = 0;
+   |                  +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-use-in-index-lvalue.stderr b/src/test/ui/borrowck/borrowck-use-in-index-lvalue.stderr
index 459cf1398b75..18e808f10d0c 100644
--- a/src/test/ui/borrowck/borrowck-use-in-index-lvalue.stderr
+++ b/src/test/ui/borrowck/borrowck-use-in-index-lvalue.stderr
@@ -5,6 +5,11 @@ LL |     let w: &mut [isize];
    |         - binding declared here but left uninitialized
 LL |     w[5] = 0;
    |     ^^^^ `*w` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let w: &mut [isize] = todo!();
+   |                         +++++++++
 
 error[E0381]: used binding `w` isn't initialized
   --> $DIR/borrowck-use-in-index-lvalue.rs:6:5
@@ -13,6 +18,11 @@ LL |     let mut w: &mut [isize];
    |         ----- binding declared here but left uninitialized
 LL |     w[5] = 0;
    |     ^^^^ `*w` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let mut w: &mut [isize] = todo!();
+   |                             +++++++++
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast-trait.stderr b/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast-trait.stderr
index 942ed4fc6cab..55f3ff553c13 100644
--- a/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast-trait.stderr
+++ b/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast-trait.stderr
@@ -5,6 +5,11 @@ LL |     let x: &i32;
    |         - binding declared here but left uninitialized
 LL |     let y = x as *const dyn Foo;
    |             ^ `*x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: &i32 = todo!();
+   |                 +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast.stderr b/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast.stderr
index f3289e239818..ea3d0d3ef51c 100644
--- a/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast.stderr
+++ b/src/test/ui/borrowck/borrowck-use-uninitialized-in-cast.stderr
@@ -5,6 +5,11 @@ LL |     let x: &i32;
    |         - binding declared here but left uninitialized
 LL |     let y = x as *const i32;
    |             ^ `*x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: &i32 = todo!();
+   |                 +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-vec-pattern-move-tail.stderr b/src/test/ui/borrowck/borrowck-vec-pattern-move-tail.stderr
index ff70ba9fcca8..0ac7df944d78 100644
--- a/src/test/ui/borrowck/borrowck-vec-pattern-move-tail.stderr
+++ b/src/test/ui/borrowck/borrowck-vec-pattern-move-tail.stderr
@@ -2,7 +2,7 @@ error[E0506]: cannot assign to `a[_]` because it is borrowed
   --> $DIR/borrowck-vec-pattern-move-tail.rs:8:5
    |
 LL |         [1, 2, ref tail @ ..] => tail,
-   |                ------------- borrow of `a[_]` occurs here
+   |                -------- borrow of `a[_]` occurs here
 ...
 LL |     a[2] = 0;
    |     ^^^^^^^^ assignment to borrowed `a[_]` occurs here
diff --git a/src/test/ui/borrowck/borrowck-vec-pattern-nesting.stderr b/src/test/ui/borrowck/borrowck-vec-pattern-nesting.stderr
index ddd89afe5bf9..c3bcb7de65da 100644
--- a/src/test/ui/borrowck/borrowck-vec-pattern-nesting.stderr
+++ b/src/test/ui/borrowck/borrowck-vec-pattern-nesting.stderr
@@ -14,7 +14,7 @@ error[E0506]: cannot assign to `vec[_]` because it is borrowed
   --> $DIR/borrowck-vec-pattern-nesting.rs:23:13
    |
 LL |         &mut [ref _b @ ..] => {
-   |               ----------- borrow of `vec[_]` occurs here
+   |               ------ borrow of `vec[_]` occurs here
 LL |
 LL |             vec[0] = Box::new(4);
    |             ^^^^^^ assignment to borrowed `vec[_]` occurs here
diff --git a/src/test/ui/borrowck/borrowck-while-cond.stderr b/src/test/ui/borrowck/borrowck-while-cond.stderr
index e41c1c55e602..5d0194989563 100644
--- a/src/test/ui/borrowck/borrowck-while-cond.stderr
+++ b/src/test/ui/borrowck/borrowck-while-cond.stderr
@@ -5,6 +5,11 @@ LL |     let x: bool;
    |         - binding declared here but left uninitialized
 LL |     while x { }
    |           ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: bool = false;
+   |                 +++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.rs b/src/test/ui/borrowck/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.rs
new file mode 100644
index 000000000000..524459291f85
--- /dev/null
+++ b/src/test/ui/borrowck/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let mut vec: Vec<i32> = Vec::new();
+    let closure = move || {
+        vec.clear();
+        let mut iter = vec.iter();
+        move || { iter.next() } //~ ERROR captured variable cannot escape `FnMut` closure bod
+    };
+}
diff --git a/src/test/ui/borrowck/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.stderr b/src/test/ui/borrowck/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.stderr
new file mode 100644
index 000000000000..78ca090feb72
--- /dev/null
+++ b/src/test/ui/borrowck/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.stderr
@@ -0,0 +1,18 @@
+error: captured variable cannot escape `FnMut` closure body
+  --> $DIR/do-not-suggest-adding-move-when-closure-is-already-marked-as-move.rs:6:9
+   |
+LL |     let mut vec: Vec<i32> = Vec::new();
+   |         ------- variable defined here
+LL |     let closure = move || {
+   |                         - inferred to be a `FnMut` closure
+LL |         vec.clear();
+   |         --- variable captured here
+LL |         let mut iter = vec.iter();
+LL |         move || { iter.next() }
+   |         ^^^^^^^^^^^^^^^^^^^^^^^ returns a closure that contains a reference to a captured variable, which then escapes the closure body
+   |
+   = note: `FnMut` closures only have access to their captured variables while they are executing...
+   = note: ...therefore, they cannot allow references to captured variables to escape
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/borrowck/issue-101119.rs b/src/test/ui/borrowck/issue-101119.rs
new file mode 100644
index 000000000000..64e52eaac06e
--- /dev/null
+++ b/src/test/ui/borrowck/issue-101119.rs
@@ -0,0 +1,16 @@
+struct State;
+
+fn once(_: impl FnOnce()) {}
+
+fn fill_memory_blocks_mt(state: &mut State) {
+    loop {
+        once(move || {
+            //~^ ERROR use of moved value: `state`
+            fill_segment(state);
+        });
+    }
+}
+
+fn fill_segment(_: &mut State) {}
+
+fn main() {}
diff --git a/src/test/ui/borrowck/issue-101119.stderr b/src/test/ui/borrowck/issue-101119.stderr
new file mode 100644
index 000000000000..a22afdc67648
--- /dev/null
+++ b/src/test/ui/borrowck/issue-101119.stderr
@@ -0,0 +1,15 @@
+error[E0382]: use of moved value: `state`
+  --> $DIR/issue-101119.rs:7:14
+   |
+LL | fn fill_memory_blocks_mt(state: &mut State) {
+   |                          ----- move occurs because `state` has type `&mut State`, which does not implement the `Copy` trait
+LL |     loop {
+LL |         once(move || {
+   |              ^^^^^^^ value moved into closure here, in previous iteration of loop
+LL |
+LL |             fill_segment(state);
+   |                          ----- use occurs due to use in closure
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/borrowck/issue-24267-flow-exit.stderr b/src/test/ui/borrowck/issue-24267-flow-exit.stderr
index b85e8f216e5d..58d1c8c0f73a 100644
--- a/src/test/ui/borrowck/issue-24267-flow-exit.stderr
+++ b/src/test/ui/borrowck/issue-24267-flow-exit.stderr
@@ -8,6 +8,10 @@ LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let x: i32 = 0;
+   |                +++
 
 error[E0381]: used binding `x` isn't initialized
   --> $DIR/issue-24267-flow-exit.rs:18:20
@@ -19,6 +23,10 @@ LL |     println!("{}", x);
    |                    ^ `x` used here but it isn't initialized
    |
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let x: i32 = 0;
+   |                +++
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/borrowck/issue-62107-match-arm-scopes.stderr b/src/test/ui/borrowck/issue-62107-match-arm-scopes.stderr
index f5d2eecfa91a..9683da919aaf 100644
--- a/src/test/ui/borrowck/issue-62107-match-arm-scopes.stderr
+++ b/src/test/ui/borrowck/issue-62107-match-arm-scopes.stderr
@@ -5,6 +5,11 @@ LL |     let e: i32;
    |         - binding declared here but left uninitialized
 LL |     match e {
    |           ^ `e` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let e: i32 = 0;
+   |                +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/reborrow-sugg-move-then-borrow.rs b/src/test/ui/borrowck/reborrow-sugg-move-then-borrow.rs
new file mode 100644
index 000000000000..31eba0740084
--- /dev/null
+++ b/src/test/ui/borrowck/reborrow-sugg-move-then-borrow.rs
@@ -0,0 +1,26 @@
+// Tests the suggestion to reborrow the first move site
+// when we move then borrow a `&mut` ref.
+
+struct State;
+
+impl IntoIterator for &mut State {
+    type IntoIter = std::vec::IntoIter<()>;
+    type Item = ();
+
+    fn into_iter(self) -> Self::IntoIter {
+        vec![].into_iter()
+    }
+}
+
+fn once(f: impl FnOnce()) {}
+
+fn fill_memory_blocks_mt(state: &mut State) {
+    for _ in state {}
+    //~^ HELP consider creating a fresh reborrow of `state` here
+    fill_segment(state);
+    //~^ ERROR borrow of moved value: `state`
+}
+
+fn fill_segment(state: &mut State) {}
+
+fn main() {}
diff --git a/src/test/ui/borrowck/reborrow-sugg-move-then-borrow.stderr b/src/test/ui/borrowck/reborrow-sugg-move-then-borrow.stderr
new file mode 100644
index 000000000000..13a2005e2ef4
--- /dev/null
+++ b/src/test/ui/borrowck/reborrow-sugg-move-then-borrow.stderr
@@ -0,0 +1,24 @@
+error[E0382]: borrow of moved value: `state`
+  --> $DIR/reborrow-sugg-move-then-borrow.rs:20:18
+   |
+LL | fn fill_memory_blocks_mt(state: &mut State) {
+   |                          ----- move occurs because `state` has type `&mut State`, which does not implement the `Copy` trait
+LL |     for _ in state {}
+   |              ----- `state` moved due to this implicit call to `.into_iter()`
+LL |
+LL |     fill_segment(state);
+   |                  ^^^^^ value borrowed here after move
+   |
+note: this function takes ownership of the receiver `self`, which moves `state`
+  --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
+   |
+LL |     fn into_iter(self) -> Self::IntoIter;
+   |                  ^^^^
+help: consider creating a fresh reborrow of `state` here
+   |
+LL |     for _ in &mut *state {}
+   |              ++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/borrowck/suggest-assign-rvalue.rs b/src/test/ui/borrowck/suggest-assign-rvalue.rs
new file mode 100644
index 000000000000..aaca9d47f0ae
--- /dev/null
+++ b/src/test/ui/borrowck/suggest-assign-rvalue.rs
@@ -0,0 +1,57 @@
+#![allow(dead_code)]
+#![feature(never_type)]
+
+#[derive(Debug, Default)]
+struct Demo {}
+
+#[derive(Debug)]
+struct DemoNoDef {}
+
+fn apple(_: u32) {}
+
+fn banana() {
+    let chaenomeles;
+    apple(chaenomeles);
+    //~^ ERROR used binding `chaenomeles` isn't initialized [E0381]
+}
+
+fn main() {
+    let my_bool: bool = bool::default();
+    println!("my_bool: {}", my_bool);
+
+    let my_float: f32;
+    println!("my_float: {}", my_float);
+    //~^ ERROR used binding `my_float` isn't initialized
+    let demo: Demo;
+    println!("demo: {:?}", demo);
+    //~^ ERROR used binding `demo` isn't initialized
+
+    let demo_no: DemoNoDef;
+    println!("demo_no: {:?}", demo_no);
+    //~^ ERROR used binding `demo_no` isn't initialized
+
+    let arr: [i32; 5];
+    println!("arr: {:?}", arr);
+    //~^ ERROR used binding `arr` isn't initialized
+    let foo: Vec<&str>;
+    println!("foo: {:?}", foo);
+    //~^ ERROR used binding `foo` isn't initialized
+
+    let my_string: String;
+    println!("my_string: {}", my_string);
+    //~^ ERROR used binding `my_string` isn't initialized
+
+    let my_int: &i32;
+    println!("my_int: {}", *my_int);
+    //~^ ERROR used binding `my_int` isn't initialized
+
+    let hello: &str;
+    println!("hello: {}", hello);
+    //~^ ERROR used binding `hello` isn't initialized
+
+    let never: !;
+    println!("never: {}", never);
+    //~^ ERROR used binding `never` isn't initialized [E0381]
+
+    banana();
+}
diff --git a/src/test/ui/borrowck/suggest-assign-rvalue.stderr b/src/test/ui/borrowck/suggest-assign-rvalue.stderr
new file mode 100644
index 000000000000..92acba640d75
--- /dev/null
+++ b/src/test/ui/borrowck/suggest-assign-rvalue.stderr
@@ -0,0 +1,138 @@
+error[E0381]: used binding `chaenomeles` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:14:11
+   |
+LL |     let chaenomeles;
+   |         ----------- binding declared here but left uninitialized
+LL |     apple(chaenomeles);
+   |           ^^^^^^^^^^^ `chaenomeles` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let chaenomeles = 0;
+   |                     +++
+
+error[E0381]: used binding `my_float` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:23:30
+   |
+LL |     let my_float: f32;
+   |         -------- binding declared here but left uninitialized
+LL |     println!("my_float: {}", my_float);
+   |                              ^^^^^^^^ `my_float` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let my_float: f32 = 0.0;
+   |                       +++++
+
+error[E0381]: used binding `demo` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:26:28
+   |
+LL |     let demo: Demo;
+   |         ---- binding declared here but left uninitialized
+LL |     println!("demo: {:?}", demo);
+   |                            ^^^^ `demo` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let demo: Demo = Default::default();
+   |                    ++++++++++++++++++++
+
+error[E0381]: used binding `demo_no` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:30:31
+   |
+LL |     let demo_no: DemoNoDef;
+   |         ------- binding declared here but left uninitialized
+LL |     println!("demo_no: {:?}", demo_no);
+   |                               ^^^^^^^ `demo_no` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let demo_no: DemoNoDef = todo!();
+   |                            +++++++++
+
+error[E0381]: used binding `arr` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:34:27
+   |
+LL |     let arr: [i32; 5];
+   |         --- binding declared here but left uninitialized
+LL |     println!("arr: {:?}", arr);
+   |                           ^^^ `arr` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let arr: [i32; 5] = todo!();
+   |                       +++++++++
+
+error[E0381]: used binding `foo` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:37:27
+   |
+LL |     let foo: Vec<&str>;
+   |         --- binding declared here but left uninitialized
+LL |     println!("foo: {:?}", foo);
+   |                           ^^^ `foo` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let foo: Vec<&str> = vec![];
+   |                        ++++++++
+
+error[E0381]: used binding `my_string` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:41:31
+   |
+LL |     let my_string: String;
+   |         --------- binding declared here but left uninitialized
+LL |     println!("my_string: {}", my_string);
+   |                               ^^^^^^^^^ `my_string` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let my_string: String = Default::default();
+   |                           ++++++++++++++++++++
+
+error[E0381]: used binding `my_int` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:45:28
+   |
+LL |     let my_int: &i32;
+   |         ------ binding declared here but left uninitialized
+LL |     println!("my_int: {}", *my_int);
+   |                            ^^^^^^^ `*my_int` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let my_int: &i32 = todo!();
+   |                      +++++++++
+
+error[E0381]: used binding `hello` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:49:27
+   |
+LL |     let hello: &str;
+   |         ----- binding declared here but left uninitialized
+LL |     println!("hello: {}", hello);
+   |                           ^^^^^ `hello` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let hello: &str = todo!();
+   |                     +++++++++
+
+error[E0381]: used binding `never` isn't initialized
+  --> $DIR/suggest-assign-rvalue.rs:53:27
+   |
+LL |     let never: !;
+   |         ----- binding declared here but left uninitialized
+LL |     println!("never: {}", never);
+   |                           ^^^^^ `never` used here but it isn't initialized
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 10 previous errors
+
+For more information about this error, try `rustc --explain E0381`.
diff --git a/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs b/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs
index 3d395d1f264a..da238205b402 100644
--- a/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs
+++ b/src/test/ui/borrowck/two-phase-nonrecv-autoref.rs
@@ -131,13 +131,13 @@ fn coerce_index_op() {
     let mut i = I(10);
     i[i[3]] = 4;
     //~^ ERROR cannot borrow `i` as immutable because it is also borrowed as mutable [E0502]
-    // Shoud be accepted with g2p
+    // Should be accepted with g2p
 
     i[3] = i[4];
 
     i[i[3]] = i[4];
     //~^ ERROR cannot borrow `i` as immutable because it is also borrowed as mutable [E0502]
-    // Shoud be accepted with g2p
+    // Should be accepted with g2p
 }
 
 fn main() {
diff --git a/src/test/ui/borrowck/two-phase-reservation-sharing-interference.rs b/src/test/ui/borrowck/two-phase-reservation-sharing-interference.rs
index e0f4afa75276..0463e22b3c2d 100644
--- a/src/test/ui/borrowck/two-phase-reservation-sharing-interference.rs
+++ b/src/test/ui/borrowck/two-phase-reservation-sharing-interference.rs
@@ -40,6 +40,6 @@ fn main() {
     //
     // (At least in theory; part of the reason this test fails is that
     // the constructed MIR throws in extra &mut reborrows which
-    // flummoxes our attmpt to delay the activation point here.)
+    // flummoxes our attempt to delay the activation point here.)
     delay.push(2);
 }
diff --git a/src/test/ui/builtin-clone-unwind.rs b/src/test/ui/builtin-clone-unwind.rs
index 3623c4a4dd05..16add6ff2f68 100644
--- a/src/test/ui/builtin-clone-unwind.rs
+++ b/src/test/ui/builtin-clone-unwind.rs
@@ -3,7 +3,6 @@
 
 #![allow(unused_variables)]
 #![allow(unused_imports)]
-// ignore-wasm32-bare compiled with panic=abort by default
 
 // Test that builtin implementations of `Clone` cleanup everything
 // in case of unwinding.
diff --git a/src/test/ui/c-variadic/variadic-ffi-1.stderr b/src/test/ui/c-variadic/variadic-ffi-1.stderr
index 176bec819d67..2ffb80f7ef61 100644
--- a/src/test/ui/c-variadic/variadic-ffi-1.stderr
+++ b/src/test/ui/c-variadic/variadic-ffi-1.stderr
@@ -18,7 +18,7 @@ LL |     fn foo(f: isize, x: u8, ...);
 help: provide the arguments
    |
 LL |         foo(/* isize */, /* u8 */);
-   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0060]: this function takes at least 2 arguments but 1 argument was supplied
   --> $DIR/variadic-ffi-1.rs:21:9
@@ -34,7 +34,7 @@ LL |     fn foo(f: isize, x: u8, ...);
 help: provide the argument
    |
 LL |         foo(1, /* u8 */);
-   |         ~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/variadic-ffi-1.rs:23:56
diff --git a/src/test/ui/catch-unwind-bang.rs b/src/test/ui/catch-unwind-bang.rs
index b31b5cab5b72..fb3503937cb5 100644
--- a/src/test/ui/catch-unwind-bang.rs
+++ b/src/test/ui/catch-unwind-bang.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 fn worker() -> ! {
     panic!()
diff --git a/src/test/ui/cfg/cfg-panic.rs b/src/test/ui/cfg/cfg-panic.rs
index fb3e5059c819..2de72d54a481 100644
--- a/src/test/ui/cfg/cfg-panic.rs
+++ b/src/test/ui/cfg/cfg-panic.rs
@@ -1,9 +1,6 @@
 // build-pass
 // compile-flags: -C panic=unwind
 // needs-unwind
-// ignore-emscripten no panic_unwind implementation
-// ignore-wasm32     no panic_unwind implementation
-// ignore-wasm64     no panic_unwind implementation
 
 
 #[cfg(panic = "abort")]
diff --git a/src/test/ui/check-cfg/allow-at-crate-level.rs b/src/test/ui/check-cfg/allow-at-crate-level.rs
new file mode 100644
index 000000000000..ce3383a2961a
--- /dev/null
+++ b/src/test/ui/check-cfg/allow-at-crate-level.rs
@@ -0,0 +1,8 @@
+// This test check that #![allow(unexpected_cfgs)] works with --cfg
+//
+// check-pass
+// compile-flags: --cfg=unexpected --check-cfg=names() -Z unstable-options
+
+#![allow(unexpected_cfgs)]
+
+fn main() {}
diff --git a/src/test/ui/check-cfg/invalid-arguments.names_simple_ident.stderr b/src/test/ui/check-cfg/invalid-arguments.names_simple_ident.stderr
index bdfbc3d54a2c..8fadcc1f9f06 100644
--- a/src/test/ui/check-cfg/invalid-arguments.names_simple_ident.stderr
+++ b/src/test/ui/check-cfg/invalid-arguments.names_simple_ident.stderr
@@ -1,2 +1,2 @@
-error: invalid `--check-cfg` argument: `names("NOT_IDENT")` (`names()` arguments must be simple identifers)
+error: invalid `--check-cfg` argument: `names("NOT_IDENT")` (`names()` arguments must be simple identifiers)
 
diff --git a/src/test/ui/check-cfg/invalid-arguments.values_simple_ident.stderr b/src/test/ui/check-cfg/invalid-arguments.values_simple_ident.stderr
index b25882baaf3e..061d3f0e971c 100644
--- a/src/test/ui/check-cfg/invalid-arguments.values_simple_ident.stderr
+++ b/src/test/ui/check-cfg/invalid-arguments.values_simple_ident.stderr
@@ -1,2 +1,2 @@
-error: invalid `--check-cfg` argument: `values("NOT_IDENT")` (`values()` first argument must be a simple identifer)
+error: invalid `--check-cfg` argument: `values("NOT_IDENT")` (`values()` first argument must be a simple identifier)
 
diff --git a/src/test/ui/check-cfg/invalid-cfg-value.stderr b/src/test/ui/check-cfg/invalid-cfg-value.stderr
index 6cce31d33928..7db2aadec177 100644
--- a/src/test/ui/check-cfg/invalid-cfg-value.stderr
+++ b/src/test/ui/check-cfg/invalid-cfg-value.stderr
@@ -15,5 +15,9 @@ LL | #[cfg(feature = "rand")]
    |
    = note: expected values for `feature` are: full, serde
 
-warning: 2 warnings emitted
+warning: unexpected condition value `rand` for condition name `feature`
+   |
+   = help: was set with `--cfg` but isn't in the `--check-cfg` expected values
+
+warning: 3 warnings emitted
 
diff --git a/src/test/ui/check-cfg/mix.rs b/src/test/ui/check-cfg/mix.rs
index 8e3d20d50458..4e488fc03ec4 100644
--- a/src/test/ui/check-cfg/mix.rs
+++ b/src/test/ui/check-cfg/mix.rs
@@ -3,7 +3,7 @@
 // we correctly lint on the `cfg!` macro and `cfg_attr` attribute.
 //
 // check-pass
-// compile-flags: --check-cfg=names() --check-cfg=values(feature,"foo") --cfg feature="bar" -Z unstable-options
+// compile-flags: --check-cfg=names() --check-cfg=values(feature,"foo") --cfg feature="bar" --cfg unknown_name -Z unstable-options
 
 #[cfg(windows)]
 fn do_windows_stuff() {}
diff --git a/src/test/ui/check-cfg/mix.stderr b/src/test/ui/check-cfg/mix.stderr
index e51b75b3d435..9cf887ec7885 100644
--- a/src/test/ui/check-cfg/mix.stderr
+++ b/src/test/ui/check-cfg/mix.stderr
@@ -28,6 +28,14 @@ warning: unexpected `cfg` condition name
 LL | #[cfg_attr(uu, test)]
    |            ^^
 
+warning: unexpected condition value `bar` for condition name `feature`
+   |
+   = help: was set with `--cfg` but isn't in the `--check-cfg` expected values
+
+warning: unexpected `unknown_name` as condition name
+   |
+   = help: was set with `--cfg` but isn't in the `--check-cfg` expected names
+
 warning: unexpected `cfg` condition name
   --> $DIR/mix.rs:35:10
    |
@@ -170,5 +178,5 @@ LL |     cfg!(all(feature = "zebra", feature = "zebra", feature = "zebra"));
    |
    = note: expected values for `feature` are: foo
 
-warning: 25 warnings emitted
+warning: 27 warnings emitted
 
diff --git a/src/test/ui/check-static-values-constraints.rs b/src/test/ui/check-static-values-constraints.rs
index eb4ecd8baca9..f6a577d0d9c9 100644
--- a/src/test/ui/check-static-values-constraints.rs
+++ b/src/test/ui/check-static-values-constraints.rs
@@ -63,7 +63,7 @@ static STATIC8: SafeStruct = SafeStruct{field1: SafeEnum::Variant1,
 // This example should fail because field1 in the base struct is not safe
 static STATIC9: SafeStruct = SafeStruct{field1: SafeEnum::Variant1,
                                         ..SafeStruct{field1: SafeEnum::Variant3(WithDtor),
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
                                                      field2: SafeEnum::Variant1}};
 
 struct UnsafeStruct;
diff --git a/src/test/ui/check-static-values-constraints.stderr b/src/test/ui/check-static-values-constraints.stderr
index 3c193ca34acc..31939f7f6db5 100644
--- a/src/test/ui/check-static-values-constraints.stderr
+++ b/src/test/ui/check-static-values-constraints.stderr
@@ -1,4 +1,4 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `SafeStruct` cannot be evaluated at compile-time
   --> $DIR/check-static-values-constraints.rs:65:43
    |
 LL |                                           ..SafeStruct{field1: SafeEnum::Variant3(WithDtor),
@@ -7,7 +7,7 @@ LL | |
 LL | |                                                      field2: SafeEnum::Variant1}};
    | |                                                                                ^- value is dropped here
    | |________________________________________________________________________________|
-   |                                                                                  statics cannot evaluate destructors
+   |                                                                                  the destructor for this type cannot be evaluated in statics
 
 error[E0010]: allocations are not allowed in statics
   --> $DIR/check-static-values-constraints.rs:79:33
diff --git a/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr b/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr
index 26f47eb684df..e6ddc6068977 100644
--- a/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr
+++ b/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr
@@ -25,8 +25,8 @@ error[E0308]: mismatched types
 LL |     with_closure_expecting_fn_with_free_region(|x: fn(&u32), y| {});
    |                                                 ^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'r> fn(&'r u32)`
-              found fn pointer `fn(&u32)`
+   = note: expected fn pointer `fn(&u32)`
+              found fn pointer `for<'a> fn(&'a u32)`
 
 error[E0308]: mismatched types
   --> $DIR/expect-fn-supply-fn.rs:39:50
@@ -34,8 +34,8 @@ error[E0308]: mismatched types
 LL |     with_closure_expecting_fn_with_bound_region(|x: fn(&'x u32), y| {});
    |                                                  ^ one type is more general than the other
    |
-   = note: expected fn pointer `fn(&'x u32)`
-              found fn pointer `for<'r> fn(&'r u32)`
+   = note: expected fn pointer `for<'a> fn(&'a u32)`
+              found fn pointer `fn(&u32)`
 
 error[E0308]: mismatched types
   --> $DIR/expect-fn-supply-fn.rs:48:50
@@ -43,8 +43,8 @@ error[E0308]: mismatched types
 LL |     with_closure_expecting_fn_with_bound_region(|x: Foo<'_>, y| {
    |                                                  ^ one type is more general than the other
    |
-   = note: expected fn pointer `fn(&u32)`
-              found fn pointer `for<'r> fn(&'r u32)`
+   = note: expected fn pointer `for<'a> fn(&'a u32)`
+              found fn pointer `fn(&u32)`
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/closure-expected-type/expect-two-infer-vars-supply-ty-with-bound-region.stderr b/src/test/ui/closure-expected-type/expect-two-infer-vars-supply-ty-with-bound-region.stderr
index db7586bee495..d5432755cfed 100644
--- a/src/test/ui/closure-expected-type/expect-two-infer-vars-supply-ty-with-bound-region.stderr
+++ b/src/test/ui/closure-expected-type/expect-two-infer-vars-supply-ty-with-bound-region.stderr
@@ -6,7 +6,7 @@ LL |     with_closure(|x: u32, y| {});
    |
 help: consider giving this closure parameter an explicit type
    |
-LL |     with_closure(|x: u32, y: B| {});
+LL |     with_closure(|x: u32, y: _| {});
    |                            +++
 
 error: aborting due to previous error
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/arrays.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/arrays.rs
index 93131b2ac4e4..f97e60daf43a 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/arrays.rs
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/arrays.rs
@@ -68,7 +68,7 @@ fn arrays_5() {
         arr[1] += 10;
     };
 
-    // c will capture `arr` completely, therefore we cannot borrow other indecies
+    // c will capture `arr` completely, therefore we cannot borrow other indices
     // into the array.
     println!("{:#?}", &arr[3..2]);
     //~^ ERROR: cannot borrow `arr` as immutable because it is also borrowed as mutable
diff --git a/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.rs b/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.rs
index 318673ef847e..972c24c23b01 100644
--- a/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.rs
+++ b/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.rs
@@ -24,7 +24,7 @@ fn main() {
     let _a = || { match l1 { L1::A => (), L1::B => () } };
     // (except if the match is already non-exhaustive)
     let _b = || { match l1 { L1::A => () } };
-    //~^ ERROR: non-exhaustive patterns: `B` not covered [E0004]
+    //~^ ERROR: non-exhaustive patterns: `L1::B` not covered [E0004]
 
     // l2 should not be captured as it is a non-exhaustive SingleVariant
     // defined in this crate
diff --git a/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.stderr b/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.stderr
index e0678bc718fa..3a5fad15421c 100644
--- a/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/match/non-exhaustive-match.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `B` not covered
+error[E0004]: non-exhaustive patterns: `L1::B` not covered
   --> $DIR/non-exhaustive-match.rs:26:25
    |
 LL |     let _b = || { match l1 { L1::A => () } };
-   |                         ^^ pattern `B` not covered
+   |                         ^^ pattern `L1::B` not covered
    |
 note: `L1` defined here
   --> $DIR/non-exhaustive-match.rs:12:14
@@ -12,8 +12,8 @@ LL | enum L1 { A, B }
    = note: the matched value is of type `L1`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL |     let _b = || { match l1 { L1::A => (), B => todo!() } };
-   |                                         ++++++++++++++
+LL |     let _b = || { match l1 { L1::A => (), L1::B => todo!() } };
+   |                                         ++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: type `E1` is non-empty
   --> $DIR/non-exhaustive-match.rs:37:25
diff --git a/src/test/ui/closures/2229_closure_analysis/match/pattern-matching-should-fail.stderr b/src/test/ui/closures/2229_closure_analysis/match/pattern-matching-should-fail.stderr
index fea5441ec673..ad061d93cb24 100644
--- a/src/test/ui/closures/2229_closure_analysis/match/pattern-matching-should-fail.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/match/pattern-matching-should-fail.stderr
@@ -76,6 +76,11 @@ LL |     let x: u8;
    |         - binding declared here but left uninitialized
 LL |     let c1 = || match x { };
    |                       ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: u8 = 0;
+   |               +++
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.fixed b/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.fixed
index 89f3931418da..ff2244a8e31b 100644
--- a/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.fixed
+++ b/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.fixed
@@ -3,7 +3,6 @@
 
 #![deny(rust_2021_incompatible_closure_captures)]
 //~^ NOTE: the lint level is defined here
-// ignore-wasm32-bare compiled with panic=abort by default
 #![feature(fn_traits)]
 #![feature(never_type)]
 
diff --git a/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.rs b/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.rs
index 6b0b10521740..52e96d013a26 100644
--- a/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.rs
+++ b/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.rs
@@ -3,7 +3,6 @@
 
 #![deny(rust_2021_incompatible_closure_captures)]
 //~^ NOTE: the lint level is defined here
-// ignore-wasm32-bare compiled with panic=abort by default
 #![feature(fn_traits)]
 #![feature(never_type)]
 
diff --git a/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.stderr b/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.stderr
index 2648b00435b3..62cfcbe95bc2 100644
--- a/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/migrations/mir_calls_to_shims.stderr
@@ -1,5 +1,5 @@
 error: changes to closure capture in Rust 2021 will affect which traits the closure implements
-  --> $DIR/mir_calls_to_shims.rs:21:38
+  --> $DIR/mir_calls_to_shims.rs:20:38
    |
 LL |     let result = panic::catch_unwind(move || {
    |                                      ^^^^^^^
diff --git a/src/test/ui/closures/2229_closure_analysis/repr_packed.rs b/src/test/ui/closures/2229_closure_analysis/repr_packed.rs
index 3ed780f51c73..f23670f63acb 100644
--- a/src/test/ui/closures/2229_closure_analysis/repr_packed.rs
+++ b/src/test/ui/closures/2229_closure_analysis/repr_packed.rs
@@ -31,7 +31,7 @@ fn test_alignment_not_affected() {
     c();
 }
 
-// `String`, `u16` are not aligned at a one byte boundry and are thus affected by repr(packed).
+// `String`, `u16` are not aligned at a one byte boundary and are thus affected by repr(packed).
 //
 // Here we test that the closure doesn't capture a reference point to `foo.x` but
 // rather capture `foo` entirely.
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/by_value.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/by_value.rs
index 2c828aed528b..f8752fe1cec0 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/by_value.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/by_value.rs
@@ -1,8 +1,8 @@
 // edition:2021
 // run-pass
 
-// Test that ByValue captures compile sucessefully especially when the captures are
-// derefenced within the closure.
+// Test that ByValue captures compile successfully especially when the captures are
+// dereferenced within the closure.
 
 #[derive(Debug, Default)]
 struct SomeLargeType;
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/disjoint-capture-in-same-closure.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/disjoint-capture-in-same-closure.rs
index 88a9816a0526..03400e0ee8d5 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/disjoint-capture-in-same-closure.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/disjoint-capture-in-same-closure.rs
@@ -1,7 +1,7 @@
 // edition:2021
 // run-pass
 
-// Tests that if a closure uses indivual fields of the same object
+// Tests that if a closure uses individual fields of the same object
 // then that case is handled properly.
 
 #![allow(unused)]
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-1.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-1.rs
index b8e464031813..624e0ff22568 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-1.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-1.rs
@@ -1,10 +1,10 @@
 // edition:2021
 // run-pass
 
-// Test that closures can catpure paths that are more precise than just one level
+// Test that closures can capture paths that are more precise than just one level
 // from the root variable.
 //
-// If the closures can handle such precison we should be able to mutate one path in the closure
+// If the closures can handle such precision we should be able to mutate one path in the closure
 // while being able to mutate another path outside the closure, where the two paths are disjoint
 // after applying two projections on the root variable.
 
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-2.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-2.rs
index 11a324d8a34e..bd8addd37812 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-2.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/multilevel-path-2.rs
@@ -3,7 +3,7 @@
 
 #![allow(unused)]
 
-// If the closures can handle such precison we should be able to read one path in the closure
+// If the closures can handle such precision we should be able to read one path in the closure
 // while being able mutate another path outside the closure, where the two paths are disjoint
 // after applying two projections on the root variable.
 
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs
index bb784774b8cd..a85335438a9f 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs
@@ -5,7 +5,7 @@
 // that is captured by the closure
 
 // More specifically we test that the if the mutable reference isn't root variable of a capture
-// but rather accessed while acessing the precise capture.
+// but rather accessed while accessing the precise capture.
 
 fn mut_tuple() {
     let mut t = (10, 10);
diff --git a/src/test/ui/closures/closure-reform-bad.stderr b/src/test/ui/closures/closure-reform-bad.stderr
index 9dfff8499fdd..4c40f70b9d0a 100644
--- a/src/test/ui/closures/closure-reform-bad.stderr
+++ b/src/test/ui/closures/closure-reform-bad.stderr
@@ -8,7 +8,7 @@ LL |     call_bare(f)
    |     |
    |     arguments to this function are incorrect
    |
-   = note: expected fn pointer `for<'r> fn(&'r str)`
+   = note: expected fn pointer `for<'a> fn(&'a str)`
                  found closure `[closure@$DIR/closure-reform-bad.rs:10:13: 10:22]`
 note: closures can only be coerced to `fn` types if they do not capture any variables
   --> $DIR/closure-reform-bad.rs:10:43
diff --git a/src/test/ui/closures/coerce-unsafe-to-closure.stderr b/src/test/ui/closures/coerce-unsafe-to-closure.stderr
index bd095c2d83d8..6ce63e829b31 100644
--- a/src/test/ui/closures/coerce-unsafe-to-closure.stderr
+++ b/src/test/ui/closures/coerce-unsafe-to-closure.stderr
@@ -6,7 +6,7 @@ LL |     let x: Option<&[u8]> = Some("foo").map(std::mem::transmute);
    |                                        |
    |                                        required by a bound introduced by this call
    |
-   = help: the trait `FnOnce<(&str,)>` is not implemented for `unsafe extern "rust-intrinsic" fn(_) -> _ {transmute::<_, _>}`
+   = help: the trait `FnOnce<(&str,)>` is not implemented for fn item `unsafe extern "rust-intrinsic" fn(_) -> _ {transmute::<_, _>}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `Option::<T>::map`
   --> $SRC_DIR/core/src/option.rs:LL:COL
diff --git a/src/test/ui/closures/issue-101696.rs b/src/test/ui/closures/issue-101696.rs
new file mode 100644
index 000000000000..0a358bd16438
--- /dev/null
+++ b/src/test/ui/closures/issue-101696.rs
@@ -0,0 +1,36 @@
+// check-pass
+
+use std::marker::PhantomData;
+
+#[derive(Default)]
+struct MyType<'a> {
+    field: usize,
+    _phantom: PhantomData<&'a ()>,
+}
+
+#[derive(Default)]
+struct MyTypeVariant<'a> {
+    field: usize,
+    _phantom: PhantomData<&'a ()>,
+}
+
+trait AsVariantTrait {
+    type Type;
+}
+
+impl<'a> AsVariantTrait for MyType<'a> {
+    type Type = MyTypeVariant<'a>;
+}
+
+type Variant<G> = <G as AsVariantTrait>::Type;
+
+fn foo<T: Default, F: FnOnce(T)>(f: F) {
+    let input = T::default();
+    f(input);
+}
+
+fn main() {
+    foo(|a: <MyType as AsVariantTrait>::Type| {
+        a.field;
+    });
+}
diff --git a/src/test/ui/closures/issue-52437.rs b/src/test/ui/closures/issue-52437.rs
index f79a0bd35486..6ac5380a5aa2 100644
--- a/src/test/ui/closures/issue-52437.rs
+++ b/src/test/ui/closures/issue-52437.rs
@@ -2,5 +2,4 @@ fn main() {
     [(); &(&'static: loop { |x| {}; }) as *const _ as usize]
     //~^ ERROR: invalid label name `'static`
     //~| ERROR: type annotations needed
-    //~| ERROR mismatched types
 }
diff --git a/src/test/ui/closures/issue-52437.stderr b/src/test/ui/closures/issue-52437.stderr
index 38d9d08ce36a..4c24a54bbbe0 100644
--- a/src/test/ui/closures/issue-52437.stderr
+++ b/src/test/ui/closures/issue-52437.stderr
@@ -15,15 +15,6 @@ help: consider giving this closure parameter an explicit type
 LL |     [(); &(&'static: loop { |x: _| {}; }) as *const _ as usize]
    |                               +++
 
-error[E0308]: mismatched types
-  --> $DIR/issue-52437.rs:2:5
-   |
-LL | fn main() {
-   |           - expected `()` because of default return type
-LL |     [(); &(&'static: loop { |x| {}; }) as *const _ as usize]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[(); _]`
+error: aborting due to 2 previous errors
 
-error: aborting due to 3 previous errors
-
-Some errors have detailed explanations: E0282, E0308.
-For more information about an error, try `rustc --explain E0282`.
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/closures/issue-84128.rs b/src/test/ui/closures/issue-84128.rs
index f81d7cfaa654..30733871b855 100644
--- a/src/test/ui/closures/issue-84128.rs
+++ b/src/test/ui/closures/issue-84128.rs
@@ -1,5 +1,5 @@
 // test for issue 84128
-// missing suggestion for similar ADT type with diffetent generic paramenter
+// missing suggestion for similar ADT type with diffetent generic parameter
 // on closure ReturnNoExpression
 
 struct Foo<T>(T);
diff --git a/src/test/ui/closures/print/closure-print-generic-verbose-1.stderr b/src/test/ui/closures/print/closure-print-generic-verbose-1.stderr
index fdaf353fe3d2..3ab7c66d11f2 100644
--- a/src/test/ui/closures/print/closure-print-generic-verbose-1.stderr
+++ b/src/test/ui/closures/print/closure-print-generic-verbose-1.stderr
@@ -2,7 +2,7 @@ error[E0382]: use of moved value: `c`
   --> $DIR/closure-print-generic-verbose-1.rs:17:5
    |
 LL |     let c = to_fn_once(move|| {
-   |         - move occurs because `c` has type `[f<T>::{closure#0} closure_kind_ty=i32 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=(Foo<&'_#10r str>, T)]`, which does not implement the `Copy` trait
+   |         - move occurs because `c` has type `[f<T>::{closure#0} closure_kind_ty=i32 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=(Foo<&'_#9r str>, T)]`, which does not implement the `Copy` trait
 ...
 LL |     c();
    |     --- `c` moved due to this call
diff --git a/src/test/ui/codegen/issue-101585-128bit-repeat.rs b/src/test/ui/codegen/issue-101585-128bit-repeat.rs
new file mode 100644
index 000000000000..c6a686597e9c
--- /dev/null
+++ b/src/test/ui/codegen/issue-101585-128bit-repeat.rs
@@ -0,0 +1,14 @@
+// Regression test for issue 101585.
+// run-pass
+
+fn main() {
+    fn min_array_ok() -> [i128; 1] {
+        [i128::MIN]
+    }
+    assert_eq!(min_array_ok(), [-170141183460469231731687303715884105728i128]);
+
+    fn min_array_nok() -> [i128; 1] {
+        [i128::MIN; 1]
+    }
+    assert_eq!(min_array_nok(), [-170141183460469231731687303715884105728i128]);
+}
diff --git a/src/test/ui/codegen/issue-99551.rs b/src/test/ui/codegen/issue-99551.rs
new file mode 100644
index 000000000000..f24874c992ea
--- /dev/null
+++ b/src/test/ui/codegen/issue-99551.rs
@@ -0,0 +1,21 @@
+// build-pass
+#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
+
+pub trait A {}
+pub trait B {}
+
+pub trait C: A + B {}
+impl<X: A + B> C for X {}
+
+pub fn test<'a, T>(view: T) -> Option<&'a mut dyn B>
+where
+    T: IntoIterator<Item = &'a mut dyn B>,
+{
+    return Some(view.into_iter().next().unwrap());
+}
+
+fn main() {
+    let mut a: Vec<Box<dyn C>> = Vec::new();
+    test(a.iter_mut().map(|c| c.as_mut() as &mut dyn B));
+}
diff --git a/src/test/ui/codemap_tests/unicode.normal.stderr b/src/test/ui/codemap_tests/unicode.normal.stderr
index 60f8cff84b30..05ceb6910dad 100644
--- a/src/test/ui/codemap_tests/unicode.normal.stderr
+++ b/src/test/ui/codemap_tests/unicode.normal.stderr
@@ -4,7 +4,7 @@ error[E0703]: invalid ABI: found `路濫狼á́́`
 LL | extern "路濫狼á́́" fn foo() {}
    |        ^^^^^^^^^ invalid ABI
    |
-   = help: valid ABIs: Rust, C, C-unwind, cdecl, cdecl-unwind, stdcall, stdcall-unwind, fastcall, fastcall-unwind, vectorcall, vectorcall-unwind, thiscall, thiscall-unwind, aapcs, aapcs-unwind, win64, win64-unwind, sysv64, sysv64-unwind, ptx-kernel, msp430-interrupt, x86-interrupt, amdgpu-kernel, efiapi, avr-interrupt, avr-non-blocking-interrupt, C-cmse-nonsecure-call, wasm, system, system-unwind, rust-intrinsic, rust-call, platform-intrinsic, unadjusted, rust-cold
+   = note: invoke `rustc --print=calling-conventions` for a full list of supported calling conventions.
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/coercion/issue-101066.rs b/src/test/ui/coercion/issue-101066.rs
new file mode 100644
index 000000000000..b658ed1e9ab7
--- /dev/null
+++ b/src/test/ui/coercion/issue-101066.rs
@@ -0,0 +1,16 @@
+// check-pass
+
+use std::convert::TryFrom;
+
+pub trait FieldElement {
+    type Integer: TryFrom<usize, Error = std::num::TryFromIntError>;
+
+    fn valid_integer_try_from<N>(i: N) -> Result<Self::Integer, ()>
+    where
+        Self::Integer: TryFrom<N>,
+    {
+        Self::Integer::try_from(i).map_err(|_| ())
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/coherence/coherence-negative-impls-copy-bad.rs b/src/test/ui/coherence/coherence-negative-impls-copy-bad.rs
new file mode 100644
index 000000000000..563f28e2291d
--- /dev/null
+++ b/src/test/ui/coherence/coherence-negative-impls-copy-bad.rs
@@ -0,0 +1,11 @@
+#![feature(negative_impls)]
+#![crate_type = "lib"]
+
+impl !Copy for str {}
+//~^ ERROR only traits defined in the current crate can be implemented
+
+impl !Copy for fn() {}
+//~^ ERROR only traits defined in the current crate can be implemented
+
+impl !Copy for () {}
+//~^ ERROR only traits defined in the current crate can be implemented
diff --git a/src/test/ui/coherence/coherence-negative-impls-copy-bad.stderr b/src/test/ui/coherence/coherence-negative-impls-copy-bad.stderr
new file mode 100644
index 000000000000..2295d6315d1c
--- /dev/null
+++ b/src/test/ui/coherence/coherence-negative-impls-copy-bad.stderr
@@ -0,0 +1,36 @@
+error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
+  --> $DIR/coherence-negative-impls-copy-bad.rs:4:1
+   |
+LL | impl !Copy for str {}
+   | ^^^^^^^^^^^^^^^---
+   | |              |
+   | |              `str` is not defined in the current crate
+   | impl doesn't use only types from inside the current crate
+   |
+   = note: define and implement a trait or new type instead
+
+error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
+  --> $DIR/coherence-negative-impls-copy-bad.rs:7:1
+   |
+LL | impl !Copy for fn() {}
+   | ^^^^^^^^^^^^^^^----
+   | |              |
+   | |              `fn()` is not defined in the current crate
+   | impl doesn't use only types from inside the current crate
+   |
+   = note: define and implement a trait or new type instead
+
+error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
+  --> $DIR/coherence-negative-impls-copy-bad.rs:10:1
+   |
+LL | impl !Copy for () {}
+   | ^^^^^^^^^^^^^^^--
+   | |              |
+   | |              this is not defined in the current crate because tuples are always foreign
+   | impl doesn't use only types from inside the current crate
+   |
+   = note: define and implement a trait or new type instead
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0117`.
diff --git a/src/test/ui/coherence/coherence-negative-impls-copy.rs b/src/test/ui/coherence/coherence-negative-impls-copy.rs
new file mode 100644
index 000000000000..7b29aade4133
--- /dev/null
+++ b/src/test/ui/coherence/coherence-negative-impls-copy.rs
@@ -0,0 +1,29 @@
+// check-pass
+// regression test for issue #101836
+
+#![feature(negative_impls, extern_types)]
+#![crate_type = "lib"]
+
+struct NonCopy;
+struct NeverCopy(NonCopy);
+
+impl !Copy for NeverCopy {}
+
+
+struct WithDrop;
+impl Drop for WithDrop { fn drop(&mut self) {} }
+
+impl !Copy for WithDrop {}
+
+
+struct Type;
+trait Trait {}
+extern {
+    type ExternType;
+}
+
+impl !Copy for &mut Type {}
+
+impl !Copy for dyn Trait {}
+
+impl !Copy for ExternType {}
diff --git a/src/test/ui/coherence/deep-bad-copy-reason.stderr b/src/test/ui/coherence/deep-bad-copy-reason.stderr
index 295538cee609..168ee57263d2 100644
--- a/src/test/ui/coherence/deep-bad-copy-reason.stderr
+++ b/src/test/ui/coherence/deep-bad-copy-reason.stderr
@@ -1,11 +1,11 @@
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/deep-bad-copy-reason.rs:33:15
+  --> $DIR/deep-bad-copy-reason.rs:33:24
    |
 LL | pub struct List<'tcx, T>(Interned<'tcx, ListS<T>>);
    |                          ------------------------ this field does not implement `Copy`
 ...
 LL | impl<'tcx, T> Copy for List<'tcx, T> {}
-   |               ^^^^
+   |                        ^^^^^^^^^^^^^
    |
 note: the `Copy` impl for `Interned<'tcx, ListS<T>>` requires that `OpaqueListContents: Sized`
   --> $DIR/deep-bad-copy-reason.rs:23:26
diff --git a/src/test/ui/command/command-current-dir.rs b/src/test/ui/command/command-current-dir.rs
index 91d8e4f381a3..69a0b486d689 100644
--- a/src/test/ui/command/command-current-dir.rs
+++ b/src/test/ui/command/command-current-dir.rs
@@ -18,7 +18,7 @@ fn main() {
     let exe = me.file_name().unwrap();
     let cwd = me.parent().unwrap();
     eprintln!("cwd={:?}", cwd);
-    // Change directory to where the exectuable is located, since this test
+    // Change directory to where the executable is located, since this test
     // fundamentally needs to use relative paths. In some cases (like
     // remote-test-server), the current_dir can be somewhere else, so make
     // sure it is something we can use. We assume we can write to this
diff --git a/src/test/ui/command/command-exec.rs b/src/test/ui/command/command-exec.rs
index 0af87214f952..032dad1840d4 100644
--- a/src/test/ui/command/command-exec.rs
+++ b/src/test/ui/command/command-exec.rs
@@ -5,6 +5,7 @@
 // ignore-pretty issue #37199
 // ignore-emscripten no processes
 // ignore-sgx no processes
+// ignore-fuchsia no execvp syscall provided
 
 #![feature(process_exec)]
 
diff --git a/src/test/ui/command/command-pre-exec.rs b/src/test/ui/command/command-pre-exec.rs
index 61914e229307..d366c5ffbfd8 100644
--- a/src/test/ui/command/command-pre-exec.rs
+++ b/src/test/ui/command/command-pre-exec.rs
@@ -6,6 +6,7 @@
 // ignore-windows - this is a unix-specific test
 // ignore-emscripten no processes
 // ignore-sgx no processes
+// ignore-fuchsia no execvp syscall
 #![feature(process_exec, rustc_private)]
 
 extern crate libc;
diff --git a/src/test/ui/command/command-uid-gid.rs b/src/test/ui/command/command-uid-gid.rs
index e1eb4b1405b1..aa4e2f5b8936 100644
--- a/src/test/ui/command/command-uid-gid.rs
+++ b/src/test/ui/command/command-uid-gid.rs
@@ -2,6 +2,7 @@
 // ignore-android
 // ignore-emscripten
 // ignore-sgx
+// ignore-fuchsia no '/bin/sh', '/bin/ls'
 
 #![feature(rustc_private)]
 
diff --git a/src/test/ui/compare-method/issue-90444.stderr b/src/test/ui/compare-method/issue-90444.stderr
index 84bbec0623fd..ee63f34b799a 100644
--- a/src/test/ui/compare-method/issue-90444.stderr
+++ b/src/test/ui/compare-method/issue-90444.stderr
@@ -5,10 +5,10 @@ LL |     fn from(_: fn((), (), &mut ())) -> Self {
    |                ^^^^^^^^^^^^^^^^^^^
    |                |
    |                types differ in mutability
-   |                help: change the parameter type to match the trait: `for<'r> fn((), (), &'r ())`
+   |                help: change the parameter type to match the trait: `for<'a> fn((), (), &'a ())`
    |
-   = note: expected fn pointer `fn(for<'r> fn((), (), &'r ())) -> A`
-              found fn pointer `fn(for<'r> fn((), (), &'r mut ())) -> A`
+   = note: expected fn pointer `fn(for<'a> fn((), (), &'a ())) -> A`
+              found fn pointer `fn(for<'a> fn((), (), &'a mut ())) -> A`
 
 error[E0053]: method `from` has an incompatible type for trait
   --> $DIR/issue-90444.rs:11:16
diff --git a/src/test/ui/const-generics/argument_order.stderr b/src/test/ui/const-generics/argument_order.stderr
index 6b33dffb434e..99122c6f5e36 100644
--- a/src/test/ui/const-generics/argument_order.stderr
+++ b/src/test/ui/const-generics/argument_order.stderr
@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/argument_order.rs:6:32
    |
 LL | struct AlsoBad<const N: usize, 'a, T, 'b, const M: usize, U> {
@@ -11,7 +11,7 @@ LL |     let _: AlsoBad<7, 'static, u32, 'static, 17, u16>;
    |                       ^^^^^^^
    |
    = note: lifetime arguments must be provided before type arguments
-   = help: reorder the arguments: lifetimes, then consts: `<'a, 'b, N, T, M, U>`
+   = help: reorder the arguments: lifetimes, then type and consts: `<'a, 'b, N, T, M, U>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/const-generics/const-generic-default-wont-borrowck.stderr b/src/test/ui/const-generics/const-generic-default-wont-borrowck.stderr
index c62f1d1d2306..0ed370b83c55 100644
--- a/src/test/ui/const-generics/const-generic-default-wont-borrowck.stderr
+++ b/src/test/ui/const-generics/const-generic-default-wont-borrowck.stderr
@@ -5,6 +5,11 @@ LL |     let s: &'static str; s.len()
    |         -                ^^^^^^^ `*s` used here but it isn't initialized
    |         |
    |         binding declared here but left uninitialized
+   |
+help: consider assigning a value
+   |
+LL |     let s: &'static str = todo!(); s.len()
+   |                         +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/const-param-before-other-params.rs b/src/test/ui/const-generics/const-param-before-other-params.rs
index da06aca308e1..cb1cebe1f68a 100644
--- a/src/test/ui/const-generics/const-param-before-other-params.rs
+++ b/src/test/ui/const-generics/const-param-before-other-params.rs
@@ -1,5 +1,5 @@
 fn bar<const X: u8, 'a>(_: &'a ()) {
-    //~^ ERROR lifetime parameters must be declared prior to const parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
 }
 
 fn foo<const X: u8, T>(_: &T) {}
diff --git a/src/test/ui/const-generics/const-param-before-other-params.stderr b/src/test/ui/const-generics/const-param-before-other-params.stderr
index 607d20c4a25f..2c7a47bbc78c 100644
--- a/src/test/ui/const-generics/const-param-before-other-params.stderr
+++ b/src/test/ui/const-generics/const-param-before-other-params.stderr
@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/const-param-before-other-params.rs:1:21
    |
 LL | fn bar<const X: u8, 'a>(_: &'a ()) {
diff --git a/src/test/ui/const-generics/const_trait_fn-issue-88433.rs b/src/test/ui/const-generics/const_trait_fn-issue-88433.rs
index 8724fa698254..6e04cfaec31f 100644
--- a/src/test/ui/const-generics/const_trait_fn-issue-88433.rs
+++ b/src/test/ui/const-generics/const_trait_fn-issue-88433.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Func<T> {
     type Output;
 
diff --git a/src/test/ui/const-generics/defaults/intermixed-lifetime.rs b/src/test/ui/const-generics/defaults/intermixed-lifetime.rs
index 578938db4c43..beaf7fc6001a 100644
--- a/src/test/ui/const-generics/defaults/intermixed-lifetime.rs
+++ b/src/test/ui/const-generics/defaults/intermixed-lifetime.rs
@@ -1,9 +1,9 @@
 // Checks that lifetimes cannot be interspersed between consts and types.
 
 struct Foo<const N: usize, 'a, T = u32>(&'a (), T);
-//~^ Error lifetime parameters must be declared prior to const parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 struct Bar<const N: usize, T = u32, 'a>(&'a (), T);
-//~^ Error lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 fn main() {}
diff --git a/src/test/ui/const-generics/defaults/intermixed-lifetime.stderr b/src/test/ui/const-generics/defaults/intermixed-lifetime.stderr
index e27976deb2b5..5cff61dd9fb9 100644
--- a/src/test/ui/const-generics/defaults/intermixed-lifetime.stderr
+++ b/src/test/ui/const-generics/defaults/intermixed-lifetime.stderr
@@ -1,10 +1,10 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/intermixed-lifetime.rs:3:28
    |
 LL | struct Foo<const N: usize, 'a, T = u32>(&'a (), T);
    |           -----------------^^---------- help: reorder the parameters: lifetimes, then consts and types: `<'a, const N: usize, T = u32>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/intermixed-lifetime.rs:6:37
    |
 LL | struct Bar<const N: usize, T = u32, 'a>(&'a (), T);
diff --git a/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs b/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs
index da087ffc3c4a..f928fc9e75b7 100644
--- a/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs
+++ b/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs
@@ -1,4 +1,4 @@
 struct Foo<const M: usize = 10, 'a>(&'a u32);
-//~^ Error lifetime parameters must be declared prior to const parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 fn main() {}
diff --git a/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr b/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr
index 55f5a5353853..ba08b4646d0f 100644
--- a/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr
+++ b/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr
@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to const parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/param-order-err-pretty-prints-default.rs:1:33
    |
 LL | struct Foo<const M: usize = 10, 'a>(&'a u32);
diff --git a/src/test/ui/const-generics/generic_const_exprs/issue-69654.stderr b/src/test/ui/const-generics/generic_const_exprs/issue-69654.stderr
index 5ad457d547a6..c3e2f8e1646f 100644
--- a/src/test/ui/const-generics/generic_const_exprs/issue-69654.stderr
+++ b/src/test/ui/const-generics/generic_const_exprs/issue-69654.stderr
@@ -4,7 +4,7 @@ error[E0423]: expected value, found type parameter `T`
 LL | impl<T> Bar<T> for [u8; T] {}
    |      -                  ^ not a value
    |      |
-   |      found this type pararmeter
+   |      found this type parameter
 
 error[E0599]: the function or associated item `foo` exists for struct `Foo<_>`, but its trait bounds were not satisfied
   --> $DIR/issue-69654.rs:17:10
diff --git a/src/test/ui/const-generics/invalid-const-arg-for-type-param.stderr b/src/test/ui/const-generics/invalid-const-arg-for-type-param.stderr
index b1b359619dcf..d955b4f9651d 100644
--- a/src/test/ui/const-generics/invalid-const-arg-for-type-param.stderr
+++ b/src/test/ui/const-generics/invalid-const-arg-for-type-param.stderr
@@ -2,15 +2,22 @@ error[E0107]: this associated function takes 0 generic arguments but 1 generic a
   --> $DIR/invalid-const-arg-for-type-param.rs:6:23
    |
 LL |     let _: u32 = 5i32.try_into::<32>().unwrap();
-   |                       ^^^^^^^^------ help: remove these generics
-   |                       |
-   |                       expected 0 generic arguments
+   |                       ^^^^^^^^ expected 0 generic arguments
    |
 note: associated function defined here, with 0 generic parameters
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
 LL |     fn try_into(self) -> Result<T, Self::Error>;
    |        ^^^^^^^^
+help: consider moving this generic argument to the `TryInto` trait, which takes up to 1 argument
+   |
+LL |     let _: u32 = TryInto::<32>::try_into(5i32).unwrap();
+   |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+help: remove these generics
+   |
+LL -     let _: u32 = 5i32.try_into::<32>().unwrap();
+LL +     let _: u32 = 5i32.try_into().unwrap();
+   |
 
 error[E0599]: no method named `f` found for struct `S` in the current scope
   --> $DIR/invalid-const-arg-for-type-param.rs:9:7
diff --git a/src/test/ui/const-generics/issue-93647.rs b/src/test/ui/const-generics/issue-93647.rs
index c1a6bf6e34d0..806540e1775e 100644
--- a/src/test/ui/const-generics/issue-93647.rs
+++ b/src/test/ui/const-generics/issue-93647.rs
@@ -1,6 +1,6 @@
 struct X<const N: usize = {
     (||1usize)()
-    //~^ ERROR cannot call
+    //~^ ERROR cannot call non-const closure
 }>;
 
 fn main() {}
diff --git a/src/test/ui/const-generics/issues/issue-83466.rs b/src/test/ui/const-generics/issues/issue-83466.rs
index c488a663fbb0..73c9301011d5 100644
--- a/src/test/ui/const-generics/issues/issue-83466.rs
+++ b/src/test/ui/const-generics/issues/issue-83466.rs
@@ -1,5 +1,5 @@
 // regression test for #83466- tests that generic arg mismatch errors between
-// consts and types are not supressed when there are explicit late bound lifetimes
+// consts and types are not suppressed when there are explicit late bound lifetimes
 
 struct S;
 impl S {
diff --git a/src/test/ui/const-generics/issues/issue-83765.stderr b/src/test/ui/const-generics/issues/issue-83765.stderr
index 28ddddf1be62..4becf3a364cf 100644
--- a/src/test/ui/const-generics/issues/issue-83765.stderr
+++ b/src/test/ui/const-generics/issues/issue-83765.stderr
@@ -1,16 +1,16 @@
-error[E0391]: cycle detected when resolving instance `<LazyUpdim<T, { T::DIM }, DIM> as TensorDimension>::DIM`
+error[E0391]: cycle detected when resolving instance `<LazyUpdim<'_, T, { T::DIM }, DIM> as TensorDimension>::DIM`
   --> $DIR/issue-83765.rs:5:5
    |
 LL |     const DIM: usize;
    |     ^^^^^^^^^^^^^^^^
    |
-note: ...which requires checking if `TensorDimension` fulfills its obligations...
+note: ...which requires computing candidate for `<LazyUpdim<'_, T, { T::DIM }, DIM> as TensorDimension>`...
   --> $DIR/issue-83765.rs:4:1
    |
 LL | trait TensorDimension {
    | ^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which again requires resolving instance `<LazyUpdim<T, { T::DIM }, DIM> as TensorDimension>::DIM`, completing the cycle
-note: cycle used when checking if `TensorDimension` fulfills its obligations
+   = note: ...which again requires resolving instance `<LazyUpdim<'_, T, { T::DIM }, DIM> as TensorDimension>::DIM`, completing the cycle
+note: cycle used when computing candidate for `<LazyUpdim<'_, T, { T::DIM }, DIM> as TensorDimension>`
   --> $DIR/issue-83765.rs:4:1
    |
 LL | trait TensorDimension {
diff --git a/src/test/ui/const-generics/issues/issue-88119.rs b/src/test/ui/const-generics/issues/issue-88119.rs
index 70dfa7f708b4..647b0eea86da 100644
--- a/src/test/ui/const-generics/issues/issue-88119.rs
+++ b/src/test/ui/const-generics/issues/issue-88119.rs
@@ -3,6 +3,7 @@
 #![allow(incomplete_features)]
 #![feature(const_trait_impl, generic_const_exprs)]
 
+#[const_trait]
 trait ConstName {
     const NAME_BYTES: &'static [u8];
 }
diff --git a/src/test/ui/const-generics/issues/issue-98629.rs b/src/test/ui/const-generics/issues/issue-98629.rs
index fc8666bbcdb7..1d2d3012a6ee 100644
--- a/src/test/ui/const-generics/issues/issue-98629.rs
+++ b/src/test/ui/const-generics/issues/issue-98629.rs
@@ -1,5 +1,6 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Trait {
     const N: usize;
 }
diff --git a/src/test/ui/const-generics/issues/issue-98629.stderr b/src/test/ui/const-generics/issues/issue-98629.stderr
index 53570220882c..4a248be76a9e 100644
--- a/src/test/ui/const-generics/issues/issue-98629.stderr
+++ b/src/test/ui/const-generics/issues/issue-98629.stderr
@@ -1,5 +1,5 @@
 error[E0046]: not all trait items implemented, missing: `N`
-  --> $DIR/issue-98629.rs:7:1
+  --> $DIR/issue-98629.rs:8:1
    |
 LL |     const N: usize;
    |     -------------- `N` from trait
diff --git a/src/test/ui/const-ptr/forbidden_slices.32bit.stderr b/src/test/ui/const-ptr/forbidden_slices.32bit.stderr
index 82a3c92e66fd..8978ab436d07 100644
--- a/src/test/ui/const-ptr/forbidden_slices.32bit.stderr
+++ b/src/test/ui/const-ptr/forbidden_slices.32bit.stderr
@@ -5,7 +5,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
-   |         inside `std::slice::from_raw_parts::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:18:34
    |
@@ -19,7 +19,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
-   |         inside `std::slice::from_raw_parts::<()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, ()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:19:33
    |
@@ -33,7 +33,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: ALLOC_ID has size 4, so pointer to 8 bytes starting at offset 0 is out-of-bounds
-   |         inside `std::slice::from_raw_parts::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:22:34
    |
@@ -92,7 +92,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: ALLOC_ID has size 8, so pointer to 8 bytes starting at offset 1 is out-of-bounds
-   |         inside `std::slice::from_raw_parts::<u64>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, u64>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:43:5
    |
@@ -111,7 +111,7 @@ LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:46:34
    |
@@ -130,7 +130,7 @@ LL |         assert!(0 < pointee_size && pointee_size <= isize::MAX as usize);
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, ()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:47:33
    |
@@ -230,7 +230,7 @@ LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:79:34
    |
@@ -249,7 +249,7 @@ LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:80:35
    |
diff --git a/src/test/ui/const-ptr/forbidden_slices.64bit.stderr b/src/test/ui/const-ptr/forbidden_slices.64bit.stderr
index f88746af9769..db42b7c98307 100644
--- a/src/test/ui/const-ptr/forbidden_slices.64bit.stderr
+++ b/src/test/ui/const-ptr/forbidden_slices.64bit.stderr
@@ -5,7 +5,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
-   |         inside `std::slice::from_raw_parts::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:18:34
    |
@@ -19,7 +19,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
-   |         inside `std::slice::from_raw_parts::<()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, ()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:19:33
    |
@@ -33,7 +33,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: ALLOC_ID has size 4, so pointer to 8 bytes starting at offset 0 is out-of-bounds
-   |         inside `std::slice::from_raw_parts::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:22:34
    |
@@ -92,7 +92,7 @@ LL |         &*ptr::slice_from_raw_parts(data, len)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
    |         dereferencing pointer failed: ALLOC_ID has size 8, so pointer to 8 bytes starting at offset 1 is out-of-bounds
-   |         inside `std::slice::from_raw_parts::<u64>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |         inside `std::slice::from_raw_parts::<'_, u64>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:43:5
    |
@@ -111,7 +111,7 @@ LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:46:34
    |
@@ -130,7 +130,7 @@ LL |         assert!(0 < pointee_size && pointee_size <= isize::MAX as usize);
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, ()>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:47:33
    |
@@ -230,7 +230,7 @@ LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:79:34
    |
@@ -249,7 +249,7 @@ LL |         unsafe { intrinsics::ptr_offset_from_unsigned(self, origin) }
   ::: $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
 LL |     unsafe { from_raw_parts(range.start, range.end.sub_ptr(range.start)) }
-   |                                          ------------------------------ inside `from_ptr_range::<u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
+   |                                          ------------------------------ inside `from_ptr_range::<'_, u32>` at $SRC_DIR/core/src/slice/raw.rs:LL:COL
    |
   ::: $DIR/forbidden_slices.rs:80:35
    |
diff --git a/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr b/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr
index 0e6be6d01ed6..c685922c456b 100644
--- a/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr
+++ b/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr
@@ -4,13 +4,13 @@ error[E0308]: mismatched types
 LL |     = [0; (i8::MAX + 1u8) as usize];
    |                      ^^^ expected `i8`, found `u8`
 
-error[E0277]: cannot add `u8` to `i8`
+error[E0277]: cannot add `u8` to `i8` in const contexts
   --> $DIR/const-eval-overflow-3b.rs:16:20
    |
 LL |     = [0; (i8::MAX + 1u8) as usize];
    |                    ^ no implementation for `i8 + u8`
    |
-   = help: the trait `Add<u8>` is not implemented for `i8`
+   = help: the trait `~const Add<u8>` is not implemented for `i8`
    = help: the following other types implement trait `Add<Rhs>`:
              <&'a f32 as Add<f32>>
              <&'a f64 as Add<f64>>
diff --git a/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr b/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
index 4fa017e04e97..b396079240a9 100644
--- a/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
+++ b/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
@@ -4,13 +4,13 @@ error[E0308]: mismatched types
 LL |     : [u32; (i8::MAX as i8 + 1u8) as usize]
    |                              ^^^ expected `i8`, found `u8`
 
-error[E0277]: cannot add `u8` to `i8`
+error[E0277]: cannot add `u8` to `i8` in const contexts
   --> $DIR/const-eval-overflow-4b.rs:9:28
    |
 LL |     : [u32; (i8::MAX as i8 + 1u8) as usize]
    |                            ^ no implementation for `i8 + u8`
    |
-   = help: the trait `Add<u8>` is not implemented for `i8`
+   = help: the trait `~const Add<u8>` is not implemented for `i8`
    = help: the following other types implement trait `Add<Rhs>`:
              <&'a f32 as Add<f32>>
              <&'a f64 as Add<f64>>
diff --git a/src/test/ui/consts/const-eval/const_let.rs b/src/test/ui/consts/const-eval/const_let.rs
index 18692dbced67..1e2bcc55b6b1 100644
--- a/src/test/ui/consts/const-eval/const_let.rs
+++ b/src/test/ui/consts/const-eval/const_let.rs
@@ -14,16 +14,16 @@ const X2: FakeNeedsDrop = { let x; x = FakeNeedsDrop; x };
 
 // error
 const Y: FakeNeedsDrop = { let mut x = FakeNeedsDrop; x = FakeNeedsDrop; x };
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 // error
 const Y2: FakeNeedsDrop = { let mut x; x = FakeNeedsDrop; x = FakeNeedsDrop; x };
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 // error
 const Z: () = { let mut x = None; x = Some(FakeNeedsDrop); };
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 // error
 const Z2: () = { let mut x; x = None; x = Some(FakeNeedsDrop); };
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
diff --git a/src/test/ui/consts/const-eval/const_let.stderr b/src/test/ui/consts/const-eval/const_let.stderr
index 47f39b703e46..63442f55718c 100644
--- a/src/test/ui/consts/const-eval/const_let.stderr
+++ b/src/test/ui/consts/const-eval/const_let.stderr
@@ -1,34 +1,34 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `FakeNeedsDrop` cannot be evaluated at compile-time
   --> $DIR/const_let.rs:16:32
    |
 LL | const Y: FakeNeedsDrop = { let mut x = FakeNeedsDrop; x = FakeNeedsDrop; x };
    |                                ^^^^^                  - value is dropped here
    |                                |
-   |                                constants cannot evaluate destructors
+   |                                the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `FakeNeedsDrop` cannot be evaluated at compile-time
   --> $DIR/const_let.rs:20:33
    |
 LL | const Y2: FakeNeedsDrop = { let mut x; x = FakeNeedsDrop; x = FakeNeedsDrop; x };
    |                                 ^^^^^                     - value is dropped here
    |                                 |
-   |                                 constants cannot evaluate destructors
+   |                                 the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<FakeNeedsDrop>` cannot be evaluated at compile-time
   --> $DIR/const_let.rs:24:21
    |
 LL | const Z: () = { let mut x = None; x = Some(FakeNeedsDrop); };
    |                     ^^^^^                                  - value is dropped here
    |                     |
-   |                     constants cannot evaluate destructors
+   |                     the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<FakeNeedsDrop>` cannot be evaluated at compile-time
   --> $DIR/const_let.rs:28:22
    |
 LL | const Z2: () = { let mut x; x = None; x = Some(FakeNeedsDrop); };
    |                      ^^^^^                                     - value is dropped here
    |                      |
-   |                      constants cannot evaluate destructors
+   |                      the destructor for this type cannot be evaluated in constants
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/consts/const-eval/issue-100878.rs b/src/test/ui/consts/const-eval/issue-100878.rs
new file mode 100644
index 000000000000..353ce5050359
--- /dev/null
+++ b/src/test/ui/consts/const-eval/issue-100878.rs
@@ -0,0 +1,8 @@
+// This checks that the const-eval ICE in issue #100878 does not recur.
+//
+// build-pass
+pub fn bitshift_data(data: [u8; 1]) -> u8 {
+    data[0] << 8
+}
+
+fn main() {}
diff --git a/src/test/ui/consts/const-eval/issue-65394.rs b/src/test/ui/consts/const-eval/issue-65394.rs
index 2518e4ed40b3..e6639826cb26 100644
--- a/src/test/ui/consts/const-eval/issue-65394.rs
+++ b/src/test/ui/consts/const-eval/issue-65394.rs
@@ -4,7 +4,7 @@
 // We will likely have to change this behavior before we allow `&mut` in a `const`.
 
 const _: Vec<i32> = {
-    let mut x = Vec::<i32>::new(); //~ ERROR destructors cannot be evaluated at compile-time
+    let mut x = Vec::<i32>::new(); //~ ERROR destructor of
     let r = &mut x; //~ ERROR mutable references are not allowed in constants
     let y = x;
     y
diff --git a/src/test/ui/consts/const-eval/issue-65394.stderr b/src/test/ui/consts/const-eval/issue-65394.stderr
index ec229d7f53a0..ae6f0e937168 100644
--- a/src/test/ui/consts/const-eval/issue-65394.stderr
+++ b/src/test/ui/consts/const-eval/issue-65394.stderr
@@ -7,11 +7,11 @@ LL |     let r = &mut x;
    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Vec<i32>` cannot be evaluated at compile-time
   --> $DIR/issue-65394.rs:7:9
    |
 LL |     let mut x = Vec::<i32>::new();
-   |         ^^^^^ constants cannot evaluate destructors
+   |         ^^^^^ the destructor for this type cannot be evaluated in constants
 ...
 LL | };
    | - value is dropped here
diff --git a/src/test/ui/consts/const-eval/livedrop.rs b/src/test/ui/consts/const-eval/livedrop.rs
index 66b7d0580808..543f1f0ecee2 100644
--- a/src/test/ui/consts/const-eval/livedrop.rs
+++ b/src/test/ui/consts/const-eval/livedrop.rs
@@ -1,6 +1,6 @@
 const _: Option<Vec<i32>> = {
     let mut never_returned = Some(Vec::new());
-    let mut always_returned = None; //~ ERROR destructors cannot be evaluated at compile-time
+    let mut always_returned = None; //~ ERROR destructor of
 
     let mut i = 0;
     loop {
diff --git a/src/test/ui/consts/const-eval/livedrop.stderr b/src/test/ui/consts/const-eval/livedrop.stderr
index 1e8b4230c6f1..d04fdb70ed30 100644
--- a/src/test/ui/consts/const-eval/livedrop.stderr
+++ b/src/test/ui/consts/const-eval/livedrop.stderr
@@ -1,8 +1,8 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<Vec<i32>>` cannot be evaluated at compile-time
   --> $DIR/livedrop.rs:3:9
    |
 LL |     let mut always_returned = None;
-   |         ^^^^^^^^^^^^^^^^^^^ constants cannot evaluate destructors
+   |         ^^^^^^^^^^^^^^^^^^^ the destructor for this type cannot be evaluated in constants
 ...
 LL |         always_returned = never_returned;
    |         --------------- value is dropped here
diff --git a/src/test/ui/consts/const-eval/ub-enum.rs b/src/test/ui/consts/const-eval/ub-enum.rs
index 0e8744e790f6..d8dc6d057a73 100644
--- a/src/test/ui/consts/const-eval/ub-enum.rs
+++ b/src/test/ui/consts/const-eval/ub-enum.rs
@@ -93,7 +93,7 @@ const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute
 //~^ ERROR is undefined behavior
 
 // All variants are uninhabited but also have data.
-// Use `0` as constant to make behavior endianess-independent.
+// Use `0` as constant to make behavior endianness-independent.
 const BAD_UNINHABITED_WITH_DATA1: Result<(i32, Never), (i32, !)> = unsafe { mem::transmute(0u64) };
 //~^ ERROR evaluation of constant value failed
 const BAD_UNINHABITED_WITH_DATA2: Result<(i32, !), (i32, Never)> = unsafe { mem::transmute(0u64) };
diff --git a/src/test/ui/consts/const-float-bits-reject-conv.stderr b/src/test/ui/consts/const-float-bits-reject-conv.stderr
index d6e993a10101..01f2f4895645 100644
--- a/src/test/ui/consts/const-float-bits-reject-conv.stderr
+++ b/src/test/ui/consts/const-float-bits-reject-conv.stderr
@@ -10,16 +10,6 @@ LL |                     panic!("const-eval error: cannot use f32::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f32_to_u32, rt_f32_to_u32) }
    |                  -------------------------------------------------------------------- inside `core::f32::<impl f32>::to_bits` at $SRC_DIR/core/src/num/f32.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32} as FnOnce<(f32,)>>::call_once - shim(fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f32,), fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32}, [closure@core::f32::<impl f32>::to_bits::{closure#0}], u32>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:27:30
    |
 LL |     const MASKED_NAN1: u32 = f32::NAN.to_bits() ^ 0x002A_AAAA;
@@ -39,16 +29,6 @@ LL |                     panic!("const-eval error: cannot use f32::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f32_to_u32, rt_f32_to_u32) }
    |                  -------------------------------------------------------------------- inside `core::f32::<impl f32>::to_bits` at $SRC_DIR/core/src/num/f32.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32} as FnOnce<(f32,)>>::call_once - shim(fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f32,), fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32}, [closure@core::f32::<impl f32>::to_bits::{closure#0}], u32>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:28:30
    |
 LL |     const MASKED_NAN2: u32 = f32::NAN.to_bits() ^ 0x0055_5555;
@@ -117,16 +97,6 @@ LL |                     panic!("const-eval error: cannot use f64::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f64_to_u64, rt_f64_to_u64) }
    |                  -------------------------------------------------------------------- inside `core::f64::<impl f64>::to_bits` at $SRC_DIR/core/src/num/f64.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64} as FnOnce<(f64,)>>::call_once - shim(fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f64,), fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64}, [closure@core::f64::<impl f64>::to_bits::{closure#0}], u64>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:54:30
    |
 LL |     const MASKED_NAN1: u64 = f64::NAN.to_bits() ^ 0x000A_AAAA_AAAA_AAAA;
@@ -146,16 +116,6 @@ LL |                     panic!("const-eval error: cannot use f64::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f64_to_u64, rt_f64_to_u64) }
    |                  -------------------------------------------------------------------- inside `core::f64::<impl f64>::to_bits` at $SRC_DIR/core/src/num/f64.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64} as FnOnce<(f64,)>>::call_once - shim(fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f64,), fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64}, [closure@core::f64::<impl f64>::to_bits::{closure#0}], u64>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:55:30
    |
 LL |     const MASKED_NAN2: u64 = f64::NAN.to_bits() ^ 0x0005_5555_5555_5555;
diff --git a/src/test/ui/consts/const-fn-error.rs b/src/test/ui/consts/const-fn-error.rs
index abe68c17a0d7..50b7ce1f8c01 100644
--- a/src/test/ui/consts/const-fn-error.rs
+++ b/src/test/ui/consts/const-fn-error.rs
@@ -3,10 +3,10 @@ const X : usize = 2;
 const fn f(x: usize) -> usize {
     let mut sum = 0;
     for i in 0..x {
-        //~^ ERROR mutable references
-        //~| ERROR cannot convert
-        //~| ERROR cannot call non-const fn
+        //~^ ERROR cannot convert
         //~| ERROR `for` is not allowed in a `const fn`
+        //~| ERROR mutable references are not allowed in constant functions
+        //~| ERROR cannot call non-const fn
         sum += i;
     }
     sum
diff --git a/src/test/ui/consts/const-for.rs b/src/test/ui/consts/const-for.rs
index 58bcb5f74ccf..8db248535583 100644
--- a/src/test/ui/consts/const-for.rs
+++ b/src/test/ui/consts/const-for.rs
@@ -3,8 +3,8 @@
 
 const _: () = {
     for _ in 0..5 {}
-    //~^ error: cannot convert
-    //~| error: cannot call non-const fn
+    //~^ error: cannot call
+    //~| error: cannot convert
 };
 
 fn main() {}
diff --git a/src/test/ui/consts/control-flow/drop-fail.precise.stderr b/src/test/ui/consts/control-flow/drop-fail.precise.stderr
index 0b0b2443a4a4..93b5f257efb7 100644
--- a/src/test/ui/consts/control-flow/drop-fail.precise.stderr
+++ b/src/test/ui/consts/control-flow/drop-fail.precise.stderr
@@ -1,14 +1,14 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<Vec<i32>>` cannot be evaluated at compile-time
   --> $DIR/drop-fail.rs:8:9
    |
 LL |     let x = Some(Vec::new());
-   |         ^ constants cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<Vec<i32>>` cannot be evaluated at compile-time
   --> $DIR/drop-fail.rs:39:9
    |
 LL |     let mut tmp = None;
-   |         ^^^^^^^ constants cannot evaluate destructors
+   |         ^^^^^^^ the destructor for this type cannot be evaluated in constants
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/consts/control-flow/drop-fail.rs b/src/test/ui/consts/control-flow/drop-fail.rs
index efa5a11c941e..41341f3121e2 100644
--- a/src/test/ui/consts/control-flow/drop-fail.rs
+++ b/src/test/ui/consts/control-flow/drop-fail.rs
@@ -6,7 +6,7 @@
 const _: Option<Vec<i32>> = {
     let y: Option<Vec<i32>> = None;
     let x = Some(Vec::new());
-    //[stock,precise]~^ ERROR destructors cannot be evaluated at compile-time
+    //[stock,precise]~^ ERROR destructor of
 
     if true {
         x
@@ -19,7 +19,7 @@ const _: Option<Vec<i32>> = {
 // existing analysis.
 const _: Vec<i32> = {
     let vec_tuple = (Vec::new(),);
-    //[stock]~^ ERROR destructors cannot be evaluated at compile-time
+    //[stock]~^ ERROR destructor of
 
     vec_tuple.0
 };
@@ -27,7 +27,7 @@ const _: Vec<i32> = {
 // This applies to single-field enum variants as well.
 const _: Vec<i32> = {
     let x: Result<_, Vec<i32>> = Ok(Vec::new());
-    //[stock]~^ ERROR destructors cannot be evaluated at compile-time
+    //[stock]~^ ERROR destructor of
 
     match x {
         Ok(x) | Err(x) => x,
@@ -37,7 +37,7 @@ const _: Vec<i32> = {
 const _: Option<Vec<i32>> = {
     let mut some = Some(Vec::new());
     let mut tmp = None;
-    //[stock,precise]~^ ERROR destructors cannot be evaluated at compile-time
+    //[stock,precise]~^ ERROR destructor of
 
     let mut i = 0;
     while i < 10 {
diff --git a/src/test/ui/consts/control-flow/drop-fail.stock.stderr b/src/test/ui/consts/control-flow/drop-fail.stock.stderr
index 72ca4fa08bc4..2cc8568026eb 100644
--- a/src/test/ui/consts/control-flow/drop-fail.stock.stderr
+++ b/src/test/ui/consts/control-flow/drop-fail.stock.stderr
@@ -1,35 +1,35 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<Vec<i32>>` cannot be evaluated at compile-time
   --> $DIR/drop-fail.rs:8:9
    |
 LL |     let x = Some(Vec::new());
-   |         ^ constants cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constants
 ...
 LL | };
    | - value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(Vec<i32>,)` cannot be evaluated at compile-time
   --> $DIR/drop-fail.rs:21:9
    |
 LL |     let vec_tuple = (Vec::new(),);
-   |         ^^^^^^^^^ constants cannot evaluate destructors
+   |         ^^^^^^^^^ the destructor for this type cannot be evaluated in constants
 ...
 LL | };
    | - value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Result<Vec<i32>, Vec<i32>>` cannot be evaluated at compile-time
   --> $DIR/drop-fail.rs:29:9
    |
 LL |     let x: Result<_, Vec<i32>> = Ok(Vec::new());
-   |         ^ constants cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constants
 ...
 LL | };
    | - value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<Vec<i32>>` cannot be evaluated at compile-time
   --> $DIR/drop-fail.rs:39:9
    |
 LL |     let mut tmp = None;
-   |         ^^^^^^^ constants cannot evaluate destructors
+   |         ^^^^^^^ the destructor for this type cannot be evaluated in constants
 ...
 LL | };
    | - value is dropped here
diff --git a/src/test/ui/consts/drop_box.rs b/src/test/ui/consts/drop_box.rs
index 58a373a96738..679974130786 100644
--- a/src/test/ui/consts/drop_box.rs
+++ b/src/test/ui/consts/drop_box.rs
@@ -1,4 +1,4 @@
 const fn f<T>(_: Box<T>) {}
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 fn main() {}
diff --git a/src/test/ui/consts/drop_box.stderr b/src/test/ui/consts/drop_box.stderr
index b9d6581e8ecc..62324939b08a 100644
--- a/src/test/ui/consts/drop_box.stderr
+++ b/src/test/ui/consts/drop_box.stderr
@@ -1,10 +1,10 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Box<T>` cannot be evaluated at compile-time
   --> $DIR/drop_box.rs:1:15
    |
 LL | const fn f<T>(_: Box<T>) {}
    |               ^           - value is dropped here
    |               |
-   |               constant functions cannot evaluate destructors
+   |               the destructor for this type cannot be evaluated in constant functions
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/drop_zst.stderr b/src/test/ui/consts/drop_zst.stderr
index d4be5aa56d9a..37758a4cbda6 100644
--- a/src/test/ui/consts/drop_zst.stderr
+++ b/src/test/ui/consts/drop_zst.stderr
@@ -1,8 +1,8 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `S` cannot be evaluated at compile-time
   --> $DIR/drop_zst.rs:14:9
    |
 LL |     let s = S;
-   |         ^ constant functions cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constant functions
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/issue-36163.stderr b/src/test/ui/consts/issue-36163.stderr
index 0626ec4bcbe1..9ac6c984cb0c 100644
--- a/src/test/ui/consts/issue-36163.stderr
+++ b/src/test/ui/consts/issue-36163.stderr
@@ -8,7 +8,7 @@ note: ...which requires const-evaluating + checking `A`...
   --> $DIR/issue-36163.rs:1:1
    |
 LL | const A: isize = Foo::B as isize;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which again requires const-evaluating + checking `Foo::B::{constant#0}`, completing the cycle
 note: cycle used when simplifying constant for the type system `Foo::B::{constant#0}`
   --> $DIR/issue-36163.rs:4:9
diff --git a/src/test/ui/consts/issue-56164.rs b/src/test/ui/consts/issue-56164.rs
index 094ca377e031..fd02d2154805 100644
--- a/src/test/ui/consts/issue-56164.rs
+++ b/src/test/ui/consts/issue-56164.rs
@@ -1,11 +1,11 @@
 const fn foo() { (||{})() }
 //~^ ERROR cannot call non-const closure
-//~| ERROR erroneous constant used [const_err]
-//~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+//~| ERROR erroneous constant
+//~| WARN this was previously accepted
 
 const fn bad(input: fn()) {
     input()
-    //~^ ERROR function pointer
+    //~^ ERROR function pointer calls are not allowed
 }
 
 fn main() {
diff --git a/src/test/ui/consts/issue-78655.stderr b/src/test/ui/consts/issue-78655.stderr
index f5b1123e7f34..6b83fa0e5a01 100644
--- a/src/test/ui/consts/issue-78655.stderr
+++ b/src/test/ui/consts/issue-78655.stderr
@@ -5,6 +5,11 @@ LL |     let x;
    |         - binding declared here but left uninitialized
 LL |     &x
    |     ^^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x = 0;
+   |           +++
 
 error: could not evaluate constant pattern
   --> $DIR/issue-78655.rs:7:9
diff --git a/src/test/ui/consts/issue-88071.rs b/src/test/ui/consts/issue-88071.rs
index 1c38c43e6c0c..f58cdb5945e5 100644
--- a/src/test/ui/consts/issue-88071.rs
+++ b/src/test/ui/consts/issue-88071.rs
@@ -2,8 +2,6 @@
 //
 // regression test for #88071
 
-#![feature(const_btree_new)]
-
 use std::collections::BTreeMap;
 
 pub struct CustomMap<K, V>(BTreeMap<K, V>);
diff --git a/src/test/ui/consts/issue-94675.rs b/src/test/ui/consts/issue-94675.rs
index 0604aab3bcd2..ce21ebdb9ac9 100644
--- a/src/test/ui/consts/issue-94675.rs
+++ b/src/test/ui/consts/issue-94675.rs
@@ -7,9 +7,8 @@ struct Foo<'a> {
 impl<'a> Foo<'a> {
     const fn spam(&mut self, baz: &mut Vec<u32>) {
         self.bar[0] = baz.len();
-        //~^ ERROR cannot call non-const fn `Vec::<u32>::len` in constant functions
-        //~| ERROR the trait bound `Vec<usize>: ~const IndexMut<usize>` is not satisfied
-        //~| ERROR cannot call non-const operator in constant functions
+        //~^ the trait bound `Vec<usize>: ~const Index<_>` is not satisfied
+        //~| the trait bound `Vec<usize>: ~const IndexMut<usize>` is not satisfied
     }
 }
 
diff --git a/src/test/ui/consts/issue-94675.stderr b/src/test/ui/consts/issue-94675.stderr
index 6665e42835b7..7ae293ffbf85 100644
--- a/src/test/ui/consts/issue-94675.stderr
+++ b/src/test/ui/consts/issue-94675.stderr
@@ -1,10 +1,15 @@
-error[E0015]: cannot call non-const fn `Vec::<u32>::len` in constant functions
-  --> $DIR/issue-94675.rs:9:27
+error[E0277]: the trait bound `Vec<usize>: ~const Index<_>` is not satisfied
+  --> $DIR/issue-94675.rs:9:9
    |
 LL |         self.bar[0] = baz.len();
-   |                           ^^^^^
+   |         ^^^^^^^^^^^ vector indices are of type `usize` or ranges of `usize`
    |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+   = help: the trait `~const Index<_>` is not implemented for `Vec<usize>`
+note: the trait `Index<_>` is implemented for `Vec<usize>`, but that implementation is not `const`
+  --> $DIR/issue-94675.rs:9:9
+   |
+LL |         self.bar[0] = baz.len();
+   |         ^^^^^^^^^^^
 
 error[E0277]: the trait bound `Vec<usize>: ~const IndexMut<usize>` is not satisfied
   --> $DIR/issue-94675.rs:9:9
@@ -18,21 +23,11 @@ note: the trait `IndexMut<usize>` is implemented for `Vec<usize>`, but that impl
    |
 LL |         self.bar[0] = baz.len();
    |         ^^^^^^^^^^^
-
-error[E0015]: cannot call non-const operator in constant functions
-  --> $DIR/issue-94675.rs:9:9
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
-LL |         self.bar[0] = baz.len();
-   |         ^^^^^^^^^^^
-   |
-note: impl defined here, but it is not `const`
-  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-   |
-LL | impl<T, I: SliceIndex<[T]>, A: Allocator> IndexMut<I> for Vec<T, A> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+LL | impl<'a> Foo<'a> where Vec<usize>: ~const IndexMut<usize> {
+   |                  ++++++++++++++++++++++++++++++++++++++++
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0015, E0277.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.rs b/src/test/ui/consts/min_const_fn/min_const_fn.rs
index 0bafaf2e81f7..c2891488c7f1 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.rs
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.rs
@@ -34,7 +34,7 @@ const fn foo35(a: bool, b: bool) -> bool { a ^ b }
 struct Foo<T: ?Sized>(T);
 impl<T> Foo<T> {
     const fn new(t: T) -> Self { Foo(t) }
-    const fn into_inner(self) -> T { self.0 } //~ destructors cannot be evaluated
+    const fn into_inner(self) -> T { self.0 } //~ destructor of
     const fn get(&self) -> &T { &self.0 }
     const fn get_mut(&mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
@@ -43,7 +43,7 @@ impl<T> Foo<T> {
 }
 impl<'a, T> Foo<T> {
     const fn new_lt(t: T) -> Self { Foo(t) }
-    const fn into_inner_lt(self) -> T { self.0 } //~ destructors cannot be evaluated
+    const fn into_inner_lt(self) -> T { self.0 } //~ destructor of
     const fn get_lt(&'a self) -> &T { &self.0 }
     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
@@ -52,7 +52,7 @@ impl<'a, T> Foo<T> {
 }
 impl<T: Sized> Foo<T> {
     const fn new_s(t: T) -> Self { Foo(t) }
-    const fn into_inner_s(self) -> T { self.0 } //~ ERROR destructors
+    const fn into_inner_s(self) -> T { self.0 } //~ ERROR destructor
     const fn get_s(&self) -> &T { &self.0 }
     const fn get_mut_s(&mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.stderr b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
index 4ad17602c845..11c79e8e2d6a 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
@@ -1,10 +1,10 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Foo<T>` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:37:25
    |
 LL |     const fn into_inner(self) -> T { self.0 }
    |                         ^^^^                - value is dropped here
    |                         |
-   |                         constant functions cannot evaluate destructors
+   |                         the destructor for this type cannot be evaluated in constant functions
 
 error[E0658]: mutable references are not allowed in constant functions
   --> $DIR/min_const_fn.rs:39:22
@@ -33,13 +33,13 @@ LL |     const fn get_mut(&mut self) -> &mut T { &mut self.0 }
    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Foo<T>` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:46:28
    |
 LL |     const fn into_inner_lt(self) -> T { self.0 }
    |                            ^^^^                - value is dropped here
    |                            |
-   |                            constant functions cannot evaluate destructors
+   |                            the destructor for this type cannot be evaluated in constant functions
 
 error[E0658]: mutable references are not allowed in constant functions
   --> $DIR/min_const_fn.rs:48:25
@@ -68,13 +68,13 @@ LL |     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Foo<T>` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:55:27
    |
 LL |     const fn into_inner_s(self) -> T { self.0 }
    |                           ^^^^                - value is dropped here
    |                           |
-   |                           constant functions cannot evaluate destructors
+   |                           the destructor for this type cannot be evaluated in constant functions
 
 error[E0658]: mutable references are not allowed in constant functions
   --> $DIR/min_const_fn.rs:57:24
@@ -191,21 +191,21 @@ LL | const fn inc(x: &mut i32) { *x += 1 }
    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `AlanTuring<impl std::fmt::Debug>` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:122:19
    |
 LL | const fn no_apit2(_x: AlanTuring<impl std::fmt::Debug>) {}
    |                   ^^                                     - value is dropped here
    |                   |
-   |                   constant functions cannot evaluate destructors
+   |                   the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `impl std::fmt::Debug` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:124:18
    |
 LL | const fn no_apit(_x: impl std::fmt::Debug) {}
    |                  ^^                         - value is dropped here
    |                  |
-   |                  constant functions cannot evaluate destructors
+   |                  the destructor for this type cannot be evaluated in constant functions
 
 error: aborting due to 24 previous errors
 
diff --git a/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs
index 8b17f6885ad3..4466f097ef4a 100644
--- a/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs
+++ b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs
@@ -8,7 +8,7 @@ trait Foo<T> {
 }
 
 trait Bar<T, U: Foo<T>> {
-    const F: u32 = (U::X, 42).1; //~ ERROR destructors cannot be evaluated at compile-time
+    const F: u32 = (U::X, 42).1; //~ ERROR destructor of
 }
 
 impl Foo<u32> for () {
diff --git a/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr
index 0b6cb2fab46f..c91c72d1fbf1 100644
--- a/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr
+++ b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr
@@ -1,10 +1,10 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(T, u32)` cannot be evaluated at compile-time
   --> $DIR/feature-gate-unleash_the_miri_inside_of_you.rs:11:20
    |
 LL |     const F: u32 = (U::X, 42).1;
    |                    ^^^^^^^^^^ - value is dropped here
    |                    |
-   |                    constants cannot evaluate destructors
+   |                    the destructor for this type cannot be evaluated in constants
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/miri_unleashed/slice_eq.rs b/src/test/ui/consts/miri_unleashed/slice_eq.rs
index fd843105daf2..83e10bf1213e 100644
--- a/src/test/ui/consts/miri_unleashed/slice_eq.rs
+++ b/src/test/ui/consts/miri_unleashed/slice_eq.rs
@@ -4,14 +4,10 @@
 #![feature(const_raw_ptr_comparison)]
 
 const EMPTY_SLICE: &[i32] = &[];
-const EMPTY_EQ: bool = EMPTY_SLICE.as_ptr().guaranteed_eq(&[] as *const _);
-const EMPTY_EQ2: bool = EMPTY_SLICE.as_ptr().guaranteed_ne(&[] as *const _);
-const EMPTY_NE: bool = EMPTY_SLICE.as_ptr().guaranteed_ne(&[1] as *const _);
-const EMPTY_NE2: bool = EMPTY_SLICE.as_ptr().guaranteed_eq(&[1] as *const _);
+const EMPTY_EQ: Option<bool> = EMPTY_SLICE.as_ptr().guaranteed_eq(&[] as *const _);
+const EMPTY_EQ2: Option<bool> = EMPTY_SLICE.as_ptr().guaranteed_eq(&[1] as *const _);
 
 fn main() {
-    assert!(!EMPTY_EQ);
-    assert!(!EMPTY_EQ2);
-    assert!(!EMPTY_NE);
-    assert!(!EMPTY_NE2);
+    assert!(EMPTY_EQ.is_none());
+    assert!(EMPTY_EQ2.is_none());
 }
diff --git a/src/test/ui/consts/ptr_comparisons.rs b/src/test/ui/consts/ptr_comparisons.rs
index 20233db09c90..0a3c2d4bedcb 100644
--- a/src/test/ui/consts/ptr_comparisons.rs
+++ b/src/test/ui/consts/ptr_comparisons.rs
@@ -14,38 +14,30 @@ const FOO: &usize = &42;
 macro_rules! check {
     (eq, $a:expr, $b:expr) => {
         pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_eq($a as *const u8, $b as *const u8));
+            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 1);
     };
     (ne, $a:expr, $b:expr) => {
         pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_ne($a as *const u8, $b as *const u8));
+            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 0);
     };
-    (!eq, $a:expr, $b:expr) => {
+    (!, $a:expr, $b:expr) => {
         pub const _: () =
-            assert!(!std::intrinsics::ptr_guaranteed_eq($a as *const u8, $b as *const u8));
-    };
-    (!ne, $a:expr, $b:expr) => {
-        pub const _: () =
-            assert!(!std::intrinsics::ptr_guaranteed_ne($a as *const u8, $b as *const u8));
+            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 2);
     };
 }
 
 check!(eq, 0, 0);
 check!(ne, 0, 1);
-check!(!eq, 0, 1);
-check!(!ne, 0, 0);
 check!(ne, FOO as *const _, 0);
-check!(!eq, FOO as *const _, 0);
+check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
+check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
+
 // We want pointers to be equal to themselves, but aren't checking this yet because
 // there are some open questions (e.g. whether function pointers to the same function
 // compare equal, they don't necessarily at runtime).
 // The case tested here should work eventually, but does not work yet.
-check!(!eq, FOO as *const _, FOO as *const _);
-check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
-check!(!eq, unsafe { (FOO as *const usize).offset(1) }, 0);
+check!(!, FOO as *const _, FOO as *const _);
 
-check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
-check!(!eq, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
 
 ///////////////////////////////////////////////////////////////////////////////
 // If any of the below start compiling, make sure to add a `check` test for it.
diff --git a/src/test/ui/consts/ptr_comparisons.stderr b/src/test/ui/consts/ptr_comparisons.stderr
index 1d47f243f01c..3de2aba5b05e 100644
--- a/src/test/ui/consts/ptr_comparisons.stderr
+++ b/src/test/ui/consts/ptr_comparisons.stderr
@@ -7,19 +7,19 @@ LL |         unsafe { intrinsics::offset(self, count) }
    |                  out-of-bounds pointer arithmetic: alloc3 has size $WORD, so pointer to $TWO_WORDS bytes starting at offset 0 is out-of-bounds
    |                  inside `ptr::const_ptr::<impl *const usize>::offset` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
    |
-  ::: $DIR/ptr_comparisons.rs:58:34
+  ::: $DIR/ptr_comparisons.rs:50:34
    |
 LL | const _: *const usize = unsafe { (FOO as *const usize).offset(2) };
-   |                                  ------------------------------- inside `_` at $DIR/ptr_comparisons.rs:58:34
+   |                                  ------------------------------- inside `_` at $DIR/ptr_comparisons.rs:50:34
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ptr_comparisons.rs:61:33
+  --> $DIR/ptr_comparisons.rs:53:33
    |
 LL |     unsafe { std::ptr::addr_of!((*(FOO as *const usize as *const [u8; 1000]))[999]) };
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: alloc3 has size $WORD, so pointer to 1000 bytes starting at offset 0 is out-of-bounds
 
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:65:27
+  --> $DIR/ptr_comparisons.rs:57:27
    |
 LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -31,7 +31,7 @@ LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) +
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:70:27
+  --> $DIR/ptr_comparisons.rs:62:27
    |
 LL | const _: usize = unsafe { *std::mem::transmute::<&&usize, &usize>(&FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -46,7 +46,7 @@ error: aborting due to 4 previous errors
 For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:65:27
+  --> $DIR/ptr_comparisons.rs:57:27
    |
 LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -59,7 +59,7 @@ LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) +
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:70:27
+  --> $DIR/ptr_comparisons.rs:62:27
    |
 LL | const _: usize = unsafe { *std::mem::transmute::<&&usize, &usize>(&FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
diff --git a/src/test/ui/consts/qualif-indirect-mutation-fail.rs b/src/test/ui/consts/qualif-indirect-mutation-fail.rs
index f74a25a346fd..a6d2934044ac 100644
--- a/src/test/ui/consts/qualif-indirect-mutation-fail.rs
+++ b/src/test/ui/consts/qualif-indirect-mutation-fail.rs
@@ -6,13 +6,13 @@
 
 // Mutable borrow of a field with drop impl.
 pub const fn f() {
-    let mut a: (u32, Option<String>) = (0, None); //~ ERROR destructors cannot be evaluated
+    let mut a: (u32, Option<String>) = (0, None); //~ ERROR destructor of
     let _ = &mut a.1;
 }
 
 // Mutable borrow of a type with drop impl.
 pub const A1: () = {
-    let mut x = None; //~ ERROR destructors cannot be evaluated
+    let mut x = None; //~ ERROR destructor of
     let mut y = Some(String::new());
     let a = &mut x;
     let b = &mut y;
@@ -28,12 +28,12 @@ pub const A2: () = {
     let b = &mut y;
     std::mem::swap(a, b);
     std::mem::forget(y);
-    let _z = x; //~ ERROR destructors cannot be evaluated
+    let _z = x; //~ ERROR destructor of
 };
 
 // Shared borrow of a type that might be !Freeze and Drop.
 pub const fn g1<T>() {
-    let x: Option<T> = None; //~ ERROR destructors cannot be evaluated
+    let x: Option<T> = None; //~ ERROR destructor of
     let _ = x.is_some();
 }
 
@@ -41,24 +41,24 @@ pub const fn g1<T>() {
 pub const fn g2<T>() {
     let x: Option<T> = None;
     let _ = x.is_some();
-    let _y = x; //~ ERROR destructors cannot be evaluated
+    let _y = x; //~ ERROR destructor of
 }
 
 // Mutable raw reference to a Drop type.
 pub const fn address_of_mut() {
-    let mut x: Option<String> = None; //~ ERROR destructors cannot be evaluated
+    let mut x: Option<String> = None; //~ ERROR destructor of
     &raw mut x;
 
-    let mut y: Option<String> = None; //~ ERROR destructors cannot be evaluated
+    let mut y: Option<String> = None; //~ ERROR destructor of
     std::ptr::addr_of_mut!(y);
 }
 
 // Const raw reference to a Drop type. Conservatively assumed to allow mutation
 // until resolution of https://github.com/rust-lang/rust/issues/56604.
 pub const fn address_of_const() {
-    let x: Option<String> = None; //~ ERROR destructors cannot be evaluated
+    let x: Option<String> = None; //~ ERROR destructor of
     &raw const x;
 
-    let y: Option<String> = None; //~ ERROR destructors cannot be evaluated
+    let y: Option<String> = None; //~ ERROR destructor of
     std::ptr::addr_of!(y);
 }
diff --git a/src/test/ui/consts/qualif-indirect-mutation-fail.stderr b/src/test/ui/consts/qualif-indirect-mutation-fail.stderr
index 713df12b7a55..6379c00e4b43 100644
--- a/src/test/ui/consts/qualif-indirect-mutation-fail.stderr
+++ b/src/test/ui/consts/qualif-indirect-mutation-fail.stderr
@@ -1,56 +1,56 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(u32, Option<String>)` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:9:9
    |
 LL |     let mut a: (u32, Option<String>) = (0, None);
-   |         ^^^^^ constant functions cannot evaluate destructors
+   |         ^^^^^ the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<String>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:15:9
    |
 LL |     let mut x = None;
-   |         ^^^^^ constants cannot evaluate destructors
+   |         ^^^^^ the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<String>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:31:9
    |
 LL |     let _z = x;
-   |         ^^ constants cannot evaluate destructors
+   |         ^^ the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<T>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:36:9
    |
 LL |     let x: Option<T> = None;
-   |         ^ constant functions cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<T>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:44:9
    |
 LL |     let _y = x;
-   |         ^^ constant functions cannot evaluate destructors
+   |         ^^ the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<String>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:52:9
    |
 LL |     let mut y: Option<String> = None;
-   |         ^^^^^ constant functions cannot evaluate destructors
+   |         ^^^^^ the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<String>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:49:9
    |
 LL |     let mut x: Option<String> = None;
-   |         ^^^^^ constant functions cannot evaluate destructors
+   |         ^^^^^ the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<String>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:62:9
    |
 LL |     let y: Option<String> = None;
-   |         ^ constant functions cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Option<String>` cannot be evaluated at compile-time
   --> $DIR/qualif-indirect-mutation-fail.rs:59:9
    |
 LL |     let x: Option<String> = None;
-   |         ^ constant functions cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in constant functions
 
 error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/consts/stable-precise-live-drops-in-libcore.rs b/src/test/ui/consts/stable-precise-live-drops-in-libcore.rs
index 2b970390f03c..7cd3dbec9314 100644
--- a/src/test/ui/consts/stable-precise-live-drops-in-libcore.rs
+++ b/src/test/ui/consts/stable-precise-live-drops-in-libcore.rs
@@ -11,7 +11,7 @@ impl<T> Either<T, T> {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "foo", since = "1.0.0")]
     pub const fn unwrap(self) -> T {
-        //~^ ERROR destructors cannot be evaluated at compile-time
+        //~^ ERROR destructor of
         match self {
             Self::Left(t) => t,
             Self::Right(t) => t,
diff --git a/src/test/ui/consts/stable-precise-live-drops-in-libcore.stderr b/src/test/ui/consts/stable-precise-live-drops-in-libcore.stderr
index a3f513541dd6..5f70391eec24 100644
--- a/src/test/ui/consts/stable-precise-live-drops-in-libcore.stderr
+++ b/src/test/ui/consts/stable-precise-live-drops-in-libcore.stderr
@@ -1,8 +1,8 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `Either<T, T>` cannot be evaluated at compile-time
   --> $DIR/stable-precise-live-drops-in-libcore.rs:13:25
    |
 LL |     pub const fn unwrap(self) -> T {
-   |                         ^^^^ constant functions cannot evaluate destructors
+   |                         ^^^^ the destructor for this type cannot be evaluated in constant functions
 ...
 LL |     }
    |     - value is dropped here
diff --git a/src/test/ui/consts/unstable-const-fn-in-libcore.rs b/src/test/ui/consts/unstable-const-fn-in-libcore.rs
index 16b36c8d56d8..ca4ed8f0b471 100644
--- a/src/test/ui/consts/unstable-const-fn-in-libcore.rs
+++ b/src/test/ui/consts/unstable-const-fn-in-libcore.rs
@@ -4,7 +4,7 @@
 // gate was not enabled in libcore.
 
 #![stable(feature = "core", since = "1.6.0")]
-#![feature(staged_api)]
+#![feature(staged_api, const_trait_impl)]
 
 enum Opt<T> {
     Some(T),
@@ -14,12 +14,12 @@ enum Opt<T> {
 impl<T> Opt<T> {
     #[rustc_const_unstable(feature = "foo", issue = "none")]
     #[stable(feature = "rust1", since = "1.0.0")]
-    const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
-    //~^ ERROR destructors cannot be evaluated at compile-time
-    //~| ERROR destructors cannot be evaluated at compile-time
+    const fn unwrap_or_else<F: ~const FnOnce() -> T>(self, f: F) -> T {
+    //~^ ERROR destructor of
+    //~| ERROR destructor of
         match self {
             Opt::Some(t) => t,
-            Opt::None => f(), //~ ERROR E0015
+            Opt::None => f(),
         }
     }
 }
diff --git a/src/test/ui/consts/unstable-const-fn-in-libcore.stderr b/src/test/ui/consts/unstable-const-fn-in-libcore.stderr
index 180f9f10cc6b..e5b00dd07abe 100644
--- a/src/test/ui/consts/unstable-const-fn-in-libcore.stderr
+++ b/src/test/ui/consts/unstable-const-fn-in-libcore.stderr
@@ -1,34 +1,21 @@
-error[E0015]: cannot call non-const closure in constant functions
-  --> $DIR/unstable-const-fn-in-libcore.rs:22:26
+error[E0493]: destructor of `F` cannot be evaluated at compile-time
+  --> $DIR/unstable-const-fn-in-libcore.rs:17:60
    |
-LL |             Opt::None => f(),
-   |                          ^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-help: consider further restricting this bound
-   |
-LL |     const fn unwrap_or_else<F: FnOnce() -> T + ~const std::ops::FnOnce<()>>(self, f: F) -> T {
-   |                                              +++++++++++++++++++++++++++++
-
-error[E0493]: destructors cannot be evaluated at compile-time
-  --> $DIR/unstable-const-fn-in-libcore.rs:17:53
-   |
-LL |     const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
-   |                                                     ^ constant functions cannot evaluate destructors
+LL |     const fn unwrap_or_else<F: ~const FnOnce() -> T>(self, f: F) -> T {
+   |                                                            ^ the destructor for this type cannot be evaluated in constant functions
 ...
 LL |     }
    |     - value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
-  --> $DIR/unstable-const-fn-in-libcore.rs:17:47
+error[E0493]: destructor of `Opt<T>` cannot be evaluated at compile-time
+  --> $DIR/unstable-const-fn-in-libcore.rs:17:54
    |
-LL |     const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
-   |                                               ^^^^ constant functions cannot evaluate destructors
+LL |     const fn unwrap_or_else<F: ~const FnOnce() -> T>(self, f: F) -> T {
+   |                                                      ^^^^ the destructor for this type cannot be evaluated in constant functions
 ...
 LL |     }
    |     - value is dropped here
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0015, E0493.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0493`.
diff --git a/src/test/ui/deriving/issue-89188-gat-hrtb.rs b/src/test/ui/deriving/issue-89188-gat-hrtb.rs
index abd85a616a4a..e8118f0c6e40 100644
--- a/src/test/ui/deriving/issue-89188-gat-hrtb.rs
+++ b/src/test/ui/deriving/issue-89188-gat-hrtb.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait CallWithShim: Sized {
     type Shim<'s>
     where
diff --git a/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.fixed b/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.fixed
index 87debfeceaaf..e566ed488c95 100644
--- a/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.fixed
+++ b/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.fixed
@@ -2,4 +2,9 @@
 
 fn main() {
     let _x = !1; //~ ERROR cannot be used as a unary operator
+    let _y = !1; //~ ERROR unexpected `1` after identifier
+    let _z = !false; //~ ERROR unexpected keyword `false` after identifier
+    let _a = !true; //~ ERROR unexpected keyword `true` after identifier
+    let v = 1 + 2;
+    let _v = !v; //~ ERROR unexpected `v` after identifier
 }
diff --git a/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.rs b/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.rs
index 015a8edcea35..1708a80505db 100644
--- a/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.rs
+++ b/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.rs
@@ -2,4 +2,9 @@
 
 fn main() {
     let _x = ~1; //~ ERROR cannot be used as a unary operator
+    let _y = not 1; //~ ERROR unexpected `1` after identifier
+    let _z = not false; //~ ERROR unexpected keyword `false` after identifier
+    let _a = not true; //~ ERROR unexpected keyword `true` after identifier
+    let v = 1 + 2;
+    let _v = not v; //~ ERROR unexpected `v` after identifier
 }
diff --git a/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.stderr b/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.stderr
index 84b81d561e90..2a3242abea49 100644
--- a/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.stderr
+++ b/src/test/ui/did_you_mean/issue-41679-tilde-bitwise-negation-attempt.stderr
@@ -4,5 +4,37 @@ error: `~` cannot be used as a unary operator
 LL |     let _x = ~1;
    |              ^ help: use `!` to perform bitwise not
 
-error: aborting due to previous error
+error: unexpected `1` after identifier
+  --> $DIR/issue-41679-tilde-bitwise-negation-attempt.rs:5:18
+   |
+LL |     let _y = not 1;
+   |              ----^
+   |              |
+   |              help: use `!` to perform bitwise not
+
+error: unexpected keyword `false` after identifier
+  --> $DIR/issue-41679-tilde-bitwise-negation-attempt.rs:6:18
+   |
+LL |     let _z = not false;
+   |              ----^^^^^
+   |              |
+   |              help: use `!` to perform logical negation
+
+error: unexpected keyword `true` after identifier
+  --> $DIR/issue-41679-tilde-bitwise-negation-attempt.rs:7:18
+   |
+LL |     let _a = not true;
+   |              ----^^^^
+   |              |
+   |              help: use `!` to perform logical negation
+
+error: unexpected `v` after identifier
+  --> $DIR/issue-41679-tilde-bitwise-negation-attempt.rs:9:18
+   |
+LL |     let _v = not v;
+   |              ----^
+   |              |
+   |              help: use `!` to perform logical negation or bitwise not
+
+error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/did_you_mean/issue-46836-identifier-not-instead-of-negation.stderr b/src/test/ui/did_you_mean/issue-46836-identifier-not-instead-of-negation.stderr
index 3ccc14bba542..14918ba89532 100644
--- a/src/test/ui/did_you_mean/issue-46836-identifier-not-instead-of-negation.stderr
+++ b/src/test/ui/did_you_mean/issue-46836-identifier-not-instead-of-negation.stderr
@@ -4,7 +4,7 @@ error: unexpected `for_you` after identifier
 LL |     if not for_you {
    |        ----^^^^^^^
    |        |
-   |        help: use `!` to perform logical negation
+   |        help: use `!` to perform logical negation or bitwise not
 
 error: unexpected `the_worst` after identifier
   --> $DIR/issue-46836-identifier-not-instead-of-negation.rs:11:15
@@ -12,13 +12,13 @@ error: unexpected `the_worst` after identifier
 LL |     while not the_worst {
    |           ----^^^^^^^^^
    |           |
-   |           help: use `!` to perform logical negation
+   |           help: use `!` to perform logical negation or bitwise not
 
 error: unexpected `println` after identifier
   --> $DIR/issue-46836-identifier-not-instead-of-negation.rs:20:9
    |
 LL |     if not  // lack of braces is [sic]
-   |        ----- help: use `!` to perform logical negation
+   |        ----- help: use `!` to perform logical negation or bitwise not
 LL |         println!("Then when?");
    |         ^^^^^^^
 
@@ -42,7 +42,7 @@ error: unexpected `2` after identifier
 LL |     let resource = not 2;
    |                    ----^
    |                    |
-   |                    help: use `!` to perform logical negation
+   |                    help: use `!` to perform bitwise not
 
 error: unexpected `be_smothered_out_before` after identifier
   --> $DIR/issue-46836-identifier-not-instead-of-negation.rs:32:27
@@ -50,7 +50,7 @@ error: unexpected `be_smothered_out_before` after identifier
 LL |     let young_souls = not be_smothered_out_before;
    |                       ----^^^^^^^^^^^^^^^^^^^^^^^
    |                       |
-   |                       help: use `!` to perform logical negation
+   |                       help: use `!` to perform logical negation or bitwise not
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr b/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr
index 26986684f0c0..81f3f2694325 100644
--- a/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr
+++ b/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr
@@ -15,13 +15,13 @@ help: Unicode character '−' (Minus Sign) looks like '-' (Minus/Hyphen), but it
 LL | const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e-11; // m³⋅kg⁻¹⋅s⁻²
    |                                                     ~
 
-error[E0277]: cannot subtract `{integer}` from `{float}`
+error[E0277]: cannot subtract `{integer}` from `{float}` in const contexts
   --> $DIR/issue-49746-unicode-confusable-in-float-literal-expt.rs:1:53
    |
 LL | const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e−11; // m³⋅kg⁻¹⋅s⁻²
    |                                                     ^ no implementation for `{float} - {integer}`
    |
-   = help: the trait `Sub<{integer}>` is not implemented for `{float}`
+   = help: the trait `~const Sub<{integer}>` is not implemented for `{float}`
    = help: the following other types implement trait `Sub<Rhs>`:
              <&'a f32 as Sub<f32>>
              <&'a f64 as Sub<f64>>
diff --git a/src/test/ui/did_you_mean/issue-54109-and_instead_of_ampersands.stderr b/src/test/ui/did_you_mean/issue-54109-and_instead_of_ampersands.stderr
index 528c62f501e0..cbe59e8e0af7 100644
--- a/src/test/ui/did_you_mean/issue-54109-and_instead_of_ampersands.stderr
+++ b/src/test/ui/did_you_mean/issue-54109-and_instead_of_ampersands.stderr
@@ -4,7 +4,7 @@ error: `and` is not a logical operator
 LL |     let _ = a and b;
    |               ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `and` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:9:10
@@ -12,7 +12,7 @@ error: `and` is not a logical operator
 LL |     if a and b {
    |          ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:20:15
@@ -20,7 +20,7 @@ error: `or` is not a logical operator
 LL |     let _ = a or b;
    |               ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:22:10
@@ -28,7 +28,7 @@ error: `or` is not a logical operator
 LL |     if a or b {
    |          ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `and` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:30:11
@@ -36,7 +36,7 @@ error: `and` is not a logical operator
 LL |     if (a and b) {
    |           ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:38:11
@@ -44,7 +44,7 @@ error: `or` is not a logical operator
 LL |     if (a or b) {
    |           ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `and` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:46:13
@@ -52,7 +52,7 @@ error: `and` is not a logical operator
 LL |     while a and b {
    |             ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:54:13
@@ -60,7 +60,7 @@ error: `or` is not a logical operator
 LL |     while a or b {
    |             ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error[E0308]: mismatched types
   --> $DIR/issue-54109-and_instead_of_ampersands.rs:13:33
diff --git a/src/test/ui/did_you_mean/issue-54109-without-witness.stderr b/src/test/ui/did_you_mean/issue-54109-without-witness.stderr
index 0350890c1fde..6455b0863f8f 100644
--- a/src/test/ui/did_you_mean/issue-54109-without-witness.stderr
+++ b/src/test/ui/did_you_mean/issue-54109-without-witness.stderr
@@ -4,7 +4,7 @@ error: `and` is not a logical operator
 LL |     let _ = a and b;
    |               ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `and` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:15:10
@@ -12,7 +12,7 @@ error: `and` is not a logical operator
 LL |     if a and b {
    |          ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:24:15
@@ -20,7 +20,7 @@ error: `or` is not a logical operator
 LL |     let _ = a or b;
    |               ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:26:10
@@ -28,7 +28,7 @@ error: `or` is not a logical operator
 LL |     if a or b {
    |          ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `and` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:34:11
@@ -36,7 +36,7 @@ error: `and` is not a logical operator
 LL |     if (a and b) {
    |           ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:42:11
@@ -44,7 +44,7 @@ error: `or` is not a logical operator
 LL |     if (a or b) {
    |           ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `and` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:50:13
@@ -52,7 +52,7 @@ error: `and` is not a logical operator
 LL |     while a and b {
    |             ^^^ help: use `&&` to perform logical conjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: `or` is not a logical operator
   --> $DIR/issue-54109-without-witness.rs:58:13
@@ -60,7 +60,7 @@ error: `or` is not a logical operator
 LL |     while a or b {
    |             ^^ help: use `||` to perform logical disjunction
    |
-   = note: unlike in e.g., python and PHP, `&&` and `||` are used for logical operators
+   = note: unlike in e.g., Python and PHP, `&&` and `||` are used for logical operators
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/drop/dynamic-drop-async.rs b/src/test/ui/drop/dynamic-drop-async.rs
index 13bd71ecb338..8f1cc6691cd8 100644
--- a/src/test/ui/drop/dynamic-drop-async.rs
+++ b/src/test/ui/drop/dynamic-drop-async.rs
@@ -6,7 +6,6 @@
 // run-pass
 // needs-unwind
 // edition:2018
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![allow(unused)]
 
diff --git a/src/test/ui/drop/dynamic-drop.rs b/src/test/ui/drop/dynamic-drop.rs
index e70686774233..9e51d3adaaa6 100644
--- a/src/test/ui/drop/dynamic-drop.rs
+++ b/src/test/ui/drop/dynamic-drop.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/drop/repeat-drop-2.rs b/src/test/ui/drop/repeat-drop-2.rs
index 59d5ef202051..3cfacea5e17f 100644
--- a/src/test/ui/drop/repeat-drop-2.rs
+++ b/src/test/ui/drop/repeat-drop-2.rs
@@ -5,7 +5,7 @@ fn borrowck_catch() {
 }
 
 const _: [String; 0] = [String::new(); 0];
-//~^ ERROR destructors cannot be evaluated at compile-time [E0493]
+//~^ ERROR destructor of `String` cannot be evaluated at compile-time [E0493]
 
 fn must_be_init() {
     let x: u8;
diff --git a/src/test/ui/drop/repeat-drop-2.stderr b/src/test/ui/drop/repeat-drop-2.stderr
index 48fa2bfa975c..7357551c4a7f 100644
--- a/src/test/ui/drop/repeat-drop-2.stderr
+++ b/src/test/ui/drop/repeat-drop-2.stderr
@@ -8,13 +8,13 @@ LL |     let _bar = foo;
 LL |     let _baz = [foo; 0];
    |                 ^^^ value used here after move
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `String` cannot be evaluated at compile-time
   --> $DIR/repeat-drop-2.rs:7:25
    |
 LL | const _: [String; 0] = [String::new(); 0];
    |                        -^^^^^^^^^^^^^----
    |                        ||
-   |                        |constants cannot evaluate destructors
+   |                        |the destructor for this type cannot be evaluated in constants
    |                        value is dropped here
 
 error[E0381]: used binding `x` isn't initialized
@@ -24,6 +24,11 @@ LL |     let x: u8;
    |         - binding declared here but left uninitialized
 LL |     let _ = [x; 0];
    |              ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x: u8 = 0;
+   |               +++
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/drop/repeat-drop.rs b/src/test/ui/drop/repeat-drop.rs
index a43612e5d858..8fd46ecaf442 100644
--- a/src/test/ui/drop/repeat-drop.rs
+++ b/src/test/ui/drop/repeat-drop.rs
@@ -1,8 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare no unwinding panic
-// ignore-avr no unwinding panic
-// ignore-nvptx64 no unwinding panic
 
 static mut CHECK: usize = 0;
 
diff --git a/src/test/ui/dyn-keyword/dyn-2018-edition-lint.stderr b/src/test/ui/dyn-keyword/dyn-2018-edition-lint.stderr
index 34699bb26582..e7db68693c06 100644
--- a/src/test/ui/dyn-keyword/dyn-2018-edition-lint.stderr
+++ b/src/test/ui/dyn-keyword/dyn-2018-edition-lint.stderr
@@ -13,9 +13,8 @@ LL | #[deny(bare_trait_objects)]
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
-   |
+LL | fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
+   |                 +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-2018-edition-lint.rs:4:35
@@ -27,9 +26,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
-   |
+LL | fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
+   |                                   +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-2018-edition-lint.rs:17:14
@@ -41,9 +39,8 @@ LL |     let _x: &SomeTrait = todo!();
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     let _x: &SomeTrait = todo!();
-LL +     let _x: &dyn SomeTrait = todo!();
-   |
+LL |     let _x: &dyn SomeTrait = todo!();
+   |              +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-2018-edition-lint.rs:4:17
@@ -55,9 +52,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
-   |
+LL | fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
+   |                 +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-2018-edition-lint.rs:4:17
@@ -69,9 +65,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
-   |
+LL | fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
+   |                 +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-2018-edition-lint.rs:4:35
@@ -83,9 +78,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
-   |
+LL | fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
+   |                                   +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-2018-edition-lint.rs:4:35
@@ -97,9 +91,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
-   |
+LL | fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
+   |                                   +++
 
 error: aborting due to 7 previous errors
 
diff --git a/src/test/ui/dyn-keyword/dyn-2021-edition-error.stderr b/src/test/ui/dyn-keyword/dyn-2021-edition-error.stderr
index 9e212c77dc77..08ee77116f0b 100644
--- a/src/test/ui/dyn-keyword/dyn-2021-edition-error.stderr
+++ b/src/test/ui/dyn-keyword/dyn-2021-edition-error.stderr
@@ -6,9 +6,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    |
 help: add `dyn` keyword before this trait
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
-   |
+LL | fn function(x: &dyn SomeTrait, y: Box<SomeTrait>) {
+   |                 +++
 
 error[E0782]: trait objects must include the `dyn` keyword
   --> $DIR/dyn-2021-edition-error.rs:3:35
@@ -18,9 +17,8 @@ LL | fn function(x: &SomeTrait, y: Box<SomeTrait>) {
    |
 help: add `dyn` keyword before this trait
    |
-LL - fn function(x: &SomeTrait, y: Box<SomeTrait>) {
-LL + fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
-   |
+LL | fn function(x: &SomeTrait, y: Box<dyn SomeTrait>) {
+   |                                   +++
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/dyn-keyword/dyn-angle-brackets.stderr b/src/test/ui/dyn-keyword/dyn-angle-brackets.stderr
index 9bc603fba546..261c2d5742f4 100644
--- a/src/test/ui/dyn-keyword/dyn-angle-brackets.stderr
+++ b/src/test/ui/dyn-keyword/dyn-angle-brackets.stderr
@@ -13,9 +13,8 @@ LL | #![deny(bare_trait_objects)]
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -         <fmt::Debug>::fmt(self, f)
-LL +         <dyn fmt::Debug>::fmt(self, f)
-   |
+LL |         <dyn fmt::Debug>::fmt(self, f)
+   |          +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/dyn-star/const.rs b/src/test/ui/dyn-star/const.rs
new file mode 100644
index 000000000000..e49caf649f89
--- /dev/null
+++ b/src/test/ui/dyn-star/const.rs
@@ -0,0 +1,14 @@
+// run-pass
+#![feature(dyn_star)]
+#![allow(unused, incomplete_features)]
+
+use std::fmt::Debug;
+
+fn make_dyn_star() {
+    let i = 42usize;
+    let dyn_i: dyn* Debug = i as dyn* Debug;
+}
+
+fn main() {
+    make_dyn_star();
+}
diff --git a/src/test/ui/dyn-star/drop.rs b/src/test/ui/dyn-star/drop.rs
new file mode 100644
index 000000000000..46b232f3dd39
--- /dev/null
+++ b/src/test/ui/dyn-star/drop.rs
@@ -0,0 +1,23 @@
+// run-pass
+// check-run-results
+#![feature(dyn_star)]
+#![allow(incomplete_features)]
+
+use std::fmt::Debug;
+
+#[derive(Debug)]
+struct Foo(usize);
+
+impl Drop for Foo {
+    fn drop(&mut self) {
+        println!("destructor called");
+    }
+}
+
+fn make_dyn_star(i: Foo) {
+    let _dyn_i: dyn* Debug = i as dyn* Debug;
+}
+
+fn main() {
+    make_dyn_star(Foo(42));
+}
diff --git a/src/test/ui/dyn-star/drop.run.stdout b/src/test/ui/dyn-star/drop.run.stdout
new file mode 100644
index 000000000000..dadb33ccf3ac
--- /dev/null
+++ b/src/test/ui/dyn-star/drop.run.stdout
@@ -0,0 +1 @@
+destructor called
diff --git a/src/test/ui/dyn-star/error.rs b/src/test/ui/dyn-star/error.rs
new file mode 100644
index 000000000000..33eff80a5fe7
--- /dev/null
+++ b/src/test/ui/dyn-star/error.rs
@@ -0,0 +1,13 @@
+#![feature(dyn_star)]
+#![allow(incomplete_features)]
+
+use std::fmt::Debug;
+
+trait Foo {}
+
+fn make_dyn_star() {
+    let i = 42;
+    let dyn_i: dyn* Foo = i as dyn* Foo; //~ ERROR trait bound `{integer}: Foo` is not satisfied
+}
+
+fn main() {}
diff --git a/src/test/ui/dyn-star/error.stderr b/src/test/ui/dyn-star/error.stderr
new file mode 100644
index 000000000000..d612ccc630ea
--- /dev/null
+++ b/src/test/ui/dyn-star/error.stderr
@@ -0,0 +1,9 @@
+error[E0277]: the trait bound `{integer}: Foo` is not satisfied
+  --> $DIR/error.rs:10:27
+   |
+LL |     let dyn_i: dyn* Foo = i as dyn* Foo;
+   |                           ^ the trait `Foo` is not implemented for `{integer}`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/dyn-star/feature-gate-dyn_star.rs b/src/test/ui/dyn-star/feature-gate-dyn_star.rs
new file mode 100644
index 000000000000..4756661cf41b
--- /dev/null
+++ b/src/test/ui/dyn-star/feature-gate-dyn_star.rs
@@ -0,0 +1,9 @@
+// Feature gate test for dyn_star
+
+/// dyn* is not necessarily the final surface syntax (if we have one at all),
+/// but for now we will support it to aid in writing tests independently.
+pub fn dyn_star_parameter(_: &dyn* Send) {
+    //~^ dyn* trait objects are unstable
+}
+
+fn main() {}
diff --git a/src/test/ui/dyn-star/feature-gate-dyn_star.stderr b/src/test/ui/dyn-star/feature-gate-dyn_star.stderr
new file mode 100644
index 000000000000..2767e9478e2e
--- /dev/null
+++ b/src/test/ui/dyn-star/feature-gate-dyn_star.stderr
@@ -0,0 +1,12 @@
+error[E0658]: dyn* trait objects are unstable
+  --> $DIR/feature-gate-dyn_star.rs:5:31
+   |
+LL | pub fn dyn_star_parameter(_: &dyn* Send) {
+   |                               ^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(dyn_star)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/dyn-star/make-dyn-star.rs b/src/test/ui/dyn-star/make-dyn-star.rs
new file mode 100644
index 000000000000..708ffa25d6fe
--- /dev/null
+++ b/src/test/ui/dyn-star/make-dyn-star.rs
@@ -0,0 +1,13 @@
+// run-pass
+#![feature(dyn_star)]
+#![allow(incomplete_features)]
+
+use std::fmt::Debug;
+
+fn make_dyn_star(i: usize) {
+    let _dyn_i: dyn* Debug = i as dyn* Debug;
+}
+
+fn main() {
+    make_dyn_star(42);
+}
diff --git a/src/test/ui/dyn-star/method.rs b/src/test/ui/dyn-star/method.rs
new file mode 100644
index 000000000000..d04958ca2aac
--- /dev/null
+++ b/src/test/ui/dyn-star/method.rs
@@ -0,0 +1,26 @@
+// run-pass
+#![feature(dyn_star)]
+#![allow(incomplete_features)]
+
+trait Foo {
+    fn get(&self) -> usize;
+}
+
+impl Foo for usize {
+    fn get(&self) -> usize {
+        *self
+    }
+}
+
+fn invoke_dyn_star(i: dyn* Foo) -> usize {
+    i.get()
+}
+
+fn make_and_invoke_dyn_star(i: usize) -> usize {
+    let dyn_i: dyn* Foo = i as dyn* Foo;
+    invoke_dyn_star(dyn_i)
+}
+
+fn main() {
+    println!("{}", make_and_invoke_dyn_star(42));
+}
diff --git a/src/test/ui/dyn-star/syntax.rs b/src/test/ui/dyn-star/syntax.rs
new file mode 100644
index 000000000000..618c72562b2a
--- /dev/null
+++ b/src/test/ui/dyn-star/syntax.rs
@@ -0,0 +1,11 @@
+// Make sure we can parse the `dyn* Trait` syntax
+//
+// check-pass
+
+#![feature(dyn_star)]
+#![allow(incomplete_features)]
+
+pub fn dyn_star_parameter(_: dyn* Send) {
+}
+
+fn main() {}
diff --git a/src/test/ui/empty/empty-never-array.rs b/src/test/ui/empty/empty-never-array.rs
index 01b99134a445..3de2b1a78a3d 100644
--- a/src/test/ui/empty/empty-never-array.rs
+++ b/src/test/ui/empty/empty-never-array.rs
@@ -8,7 +8,7 @@ enum Helper<T, U> {
 
 fn transmute<T, U>(t: T) -> U {
     let Helper::U(u) = Helper::T(t, []);
-    //~^ ERROR refutable pattern in local binding: `T(_, _)` not covered
+    //~^ ERROR refutable pattern in local binding: `Helper::T(_, _)` not covered
     u
 }
 
diff --git a/src/test/ui/empty/empty-never-array.stderr b/src/test/ui/empty/empty-never-array.stderr
index 909aa73a74a3..adf782743680 100644
--- a/src/test/ui/empty/empty-never-array.stderr
+++ b/src/test/ui/empty/empty-never-array.stderr
@@ -1,8 +1,8 @@
-error[E0005]: refutable pattern in local binding: `T(_, _)` not covered
+error[E0005]: refutable pattern in local binding: `Helper::T(_, _)` not covered
   --> $DIR/empty-never-array.rs:10:9
    |
 LL |     let Helper::U(u) = Helper::T(t, []);
-   |         ^^^^^^^^^^^^ pattern `T(_, _)` not covered
+   |         ^^^^^^^^^^^^ pattern `Helper::T(_, _)` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -18,7 +18,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let u = if let Helper::U(u) = Helper::T(t, []) { u } else { todo!() };
    |     ++++++++++                                     ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Helper::U(u) = Helper::T(t, []) else { todo!() };
    |                                         ++++++++++++++++
diff --git a/src/test/ui/env-funky-keys.rs b/src/test/ui/env-funky-keys.rs
index 4548d3339472..46e20d8c61f5 100644
--- a/src/test/ui/env-funky-keys.rs
+++ b/src/test/ui/env-funky-keys.rs
@@ -6,6 +6,7 @@
 // ignore-emscripten no execve
 // ignore-sgx no execve
 // ignore-vxworks no execve
+// ignore-fuchsia no 'execve'
 // no-prefer-dynamic
 
 #![feature(rustc_private)]
diff --git a/src/test/ui/error-codes/E0004.stderr b/src/test/ui/error-codes/E0004.stderr
index 8ba151d9e65f..4ac8c904f053 100644
--- a/src/test/ui/error-codes/E0004.stderr
+++ b/src/test/ui/error-codes/E0004.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `HastaLaVistaBaby` not covered
+error[E0004]: non-exhaustive patterns: `Terminator::HastaLaVistaBaby` not covered
   --> $DIR/E0004.rs:9:11
    |
 LL |     match x {
-   |           ^ pattern `HastaLaVistaBaby` not covered
+   |           ^ pattern `Terminator::HastaLaVistaBaby` not covered
    |
 note: `Terminator` defined here
   --> $DIR/E0004.rs:2:5
@@ -15,7 +15,7 @@ LL |     HastaLaVistaBaby,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Terminator::TalkToMyHand => {}
-LL +         HastaLaVistaBaby => todo!()
+LL +         Terminator::HastaLaVistaBaby => todo!()
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/error-codes/E0005.stderr b/src/test/ui/error-codes/E0005.stderr
index f01a77bd374b..de8e6bac486c 100644
--- a/src/test/ui/error-codes/E0005.stderr
+++ b/src/test/ui/error-codes/E0005.stderr
@@ -19,7 +19,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let y = if let Some(y) = x { y } else { todo!() };
    |     ++++++++++                 ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Some(y) = x else { todo!() };
    |                     ++++++++++++++++
diff --git a/src/test/ui/error-codes/E0057.stderr b/src/test/ui/error-codes/E0057.stderr
index 2307f52c93bc..bea226f09dcb 100644
--- a/src/test/ui/error-codes/E0057.stderr
+++ b/src/test/ui/error-codes/E0057.stderr
@@ -12,7 +12,7 @@ LL |     let f = |x| x * 3;
 help: provide the argument
    |
 LL |     let a = f(/* value */);
-   |             ~~~~~~~~~~~~~~
+   |              ~~~~~~~~~~~~~
 
 error[E0057]: this function takes 1 argument but 2 arguments were supplied
   --> $DIR/E0057.rs:5:13
@@ -28,7 +28,7 @@ LL |     let f = |x| x * 3;
 help: remove the extra argument
    |
 LL |     let c = f(2);
-   |             ~~~~
+   |              ~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/error-codes/E0060.stderr b/src/test/ui/error-codes/E0060.stderr
index 644fd5983387..934a18d896dc 100644
--- a/src/test/ui/error-codes/E0060.stderr
+++ b/src/test/ui/error-codes/E0060.stderr
@@ -12,7 +12,7 @@ LL |     fn printf(_: *const u8, ...) -> u32;
 help: provide the argument
    |
 LL |     unsafe { printf(/* *const u8 */); }
-   |              ~~~~~~~~~~~~~~~~~~~~~~~
+   |                    ~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0061.stderr b/src/test/ui/error-codes/E0061.stderr
index fa55db0924d2..fa4ccbe6677c 100644
--- a/src/test/ui/error-codes/E0061.stderr
+++ b/src/test/ui/error-codes/E0061.stderr
@@ -12,7 +12,7 @@ LL | fn f(a: u16, b: &str) {}
 help: provide the argument
    |
 LL |     f(0, /* &str */);
-   |     ~~~~~~~~~~~~~~~~
+   |      ~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/E0061.rs:9:5
@@ -28,7 +28,7 @@ LL | fn f2(a: u16) {}
 help: provide the argument
    |
 LL |     f2(/* u16 */);
-   |     ~~~~~~~~~~~~~
+   |       ~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/explore-issue-38412.stderr b/src/test/ui/explore-issue-38412.stderr
index e3f82137ab3b..08dadb4db851 100644
--- a/src/test/ui/explore-issue-38412.stderr
+++ b/src/test/ui/explore-issue-38412.stderr
@@ -43,19 +43,19 @@ LL |     t.2;
    = note: see issue #38412 <https://github.com/rust-lang/rust/issues/38412> for more information
    = help: add `#![feature(unstable_undeclared)]` to the crate attributes to enable
 
-error[E0616]: field `3` of struct `Tuple` is private
+error[E0616]: field `3` of struct `pub_and_stability::Tuple` is private
   --> $DIR/explore-issue-38412.rs:36:7
    |
 LL |     t.3;
    |       ^ private field
 
-error[E0616]: field `4` of struct `Tuple` is private
+error[E0616]: field `4` of struct `pub_and_stability::Tuple` is private
   --> $DIR/explore-issue-38412.rs:37:7
    |
 LL |     t.4;
    |       ^ private field
 
-error[E0616]: field `5` of struct `Tuple` is private
+error[E0616]: field `5` of struct `pub_and_stability::Tuple` is private
   --> $DIR/explore-issue-38412.rs:38:7
    |
 LL |     t.5;
diff --git a/src/test/ui/expr/malformed_closure/ruby_style_closure.stderr b/src/test/ui/expr/malformed_closure/ruby_style_closure.stderr
index 9db9cfc7ff02..759d79493a9c 100644
--- a/src/test/ui/expr/malformed_closure/ruby_style_closure.stderr
+++ b/src/test/ui/expr/malformed_closure/ruby_style_closure.stderr
@@ -14,7 +14,7 @@ LL |       let p = Some(45).and_then({
 LL | |
 LL | |         |x| println!("doubling {}", x);
 LL | |         Some(x * 2)
-   | |         -----------
+   | |         ----------- this tail expression is of type `std::option::Option<_>`
 LL | |
 LL | |     });
    | |_____^ expected an `FnOnce<({integer},)>` closure, found `Option<_>`
diff --git a/src/test/ui/extern-flag/empty-extern-arg.rs b/src/test/ui/extern-flag/empty-extern-arg.rs
index 3170537b0e0a..2f4ae7d8e70f 100644
--- a/src/test/ui/extern-flag/empty-extern-arg.rs
+++ b/src/test/ui/extern-flag/empty-extern-arg.rs
@@ -1,6 +1,6 @@
 // compile-flags: --extern std=
 // error-pattern: extern location for std does not exist
 // needs-unwind since it affects the error output
-// ignore-emscripten compiled with panic=abort, personality not required
+// ignore-emscripten missing eh_catch_typeinfo lang item
 
 fn main() {}
diff --git a/src/test/ui/extern/extern-wrong-value-type.stderr b/src/test/ui/extern/extern-wrong-value-type.stderr
index c6f0d5df9b53..ff2934a2ba88 100644
--- a/src/test/ui/extern/extern-wrong-value-type.stderr
+++ b/src/test/ui/extern/extern-wrong-value-type.stderr
@@ -6,7 +6,7 @@ LL |     is_fn(f);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `Fn<()>` is not implemented for `extern "C" fn() {f}`
+   = help: the trait `Fn<()>` is not implemented for fn item `extern "C" fn() {f}`
    = note: wrap the `extern "C" fn() {f}` in a closure with no arguments: `|| { /* code */ }`
 note: required by a bound in `is_fn`
   --> $DIR/extern-wrong-value-type.rs:4:28
diff --git a/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs b/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
index 7a91cbdc2f5d..233120c92f38 100644
--- a/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
+++ b/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // ignore-emscripten no threads support
 
 // rust-lang/rust#64655: with panic=unwind, a panic from a subroutine
diff --git a/src/test/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs b/src/test/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs
index e84ff41b344a..3b263e58cbe8 100644
--- a/src/test/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs
+++ b/src/test/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // ignore-emscripten no threads support
 
 // rust-lang/rust#64655: with panic=unwind, a panic from a subroutine
diff --git a/src/test/ui/feature-gates/feature-gate-collapse_debuginfo.rs b/src/test/ui/feature-gates/feature-gate-collapse_debuginfo.rs
new file mode 100644
index 000000000000..f73bf579f6d1
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-collapse_debuginfo.rs
@@ -0,0 +1,7 @@
+#[collapse_debuginfo]
+//~^ ERROR the `#[collapse_debuginfo]` attribute is an experimental feature
+macro_rules! foo {
+    ($e:expr) => { $e }
+}
+
+fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-collapse_debuginfo.stderr b/src/test/ui/feature-gates/feature-gate-collapse_debuginfo.stderr
new file mode 100644
index 000000000000..2cbde893af9b
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-collapse_debuginfo.stderr
@@ -0,0 +1,12 @@
+error[E0658]: the `#[collapse_debuginfo]` attribute is an experimental feature
+  --> $DIR/feature-gate-collapse_debuginfo.rs:1:1
+   |
+LL | #[collapse_debuginfo]
+   | ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #100758 <https://github.com/rust-lang/rust/issues/100758> for more information
+   = help: add `#![feature(collapse_debuginfo)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr b/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr
index f8349391a0fe..5ced344f13f3 100644
--- a/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr
+++ b/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr
@@ -19,7 +19,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let _x = if let Ok(_x) = foo() { _x } else { todo!() };
    |     +++++++++++                    +++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Ok(_x) = foo() else { todo!() };
    |                        ++++++++++++++++
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs b/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
deleted file mode 100644
index c5c134514889..000000000000
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-use std::ops::Deref;
-
-trait PointerFamily<U> {
-    type Pointer<T>: Deref<Target = T>;
-    //~^ ERROR generic associated types are unstable
-    type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
-    //~^ ERROR generic associated types are unstable
-    //~| ERROR where clauses on associated types are unstable
-}
-
-struct Foo;
-
-impl PointerFamily<u32> for Foo {
-    type Pointer<Usize> = Box<Usize>;
-    //~^ ERROR generic associated types are unstable
-    type Pointer2<U32> = Box<U32>;
-    //~^ ERROR generic associated types are unstable
-    //~| ERROR the trait bound `U32: Clone` is not satisfied
-}
-
-trait Bar {
-    type Assoc where Self: Sized;
-    //~^ ERROR where clauses on associated types are unstable
-}
-
-impl Bar for Foo {
-    type Assoc = Foo where Self: Sized;
-    //~^ ERROR where clauses on associated types are unstable
-}
-
-fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr b/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
deleted file mode 100644
index 12a40ff0a12f..000000000000
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
+++ /dev/null
@@ -1,78 +0,0 @@
-error[E0658]: generic associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:4:5
-   |
-LL |     type Pointer<T>: Deref<Target = T>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: generic associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:6:5
-   |
-LL |     type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: where clauses on associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:6:5
-   |
-LL |     type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: generic associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:14:5
-   |
-LL |     type Pointer<Usize> = Box<Usize>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: generic associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:16:5
-   |
-LL |     type Pointer2<U32> = Box<U32>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: where clauses on associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:22:5
-   |
-LL |     type Assoc where Self: Sized;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: where clauses on associated types are unstable
-  --> $DIR/feature-gate-generic_associated_types.rs:27:5
-   |
-LL |     type Assoc = Foo where Self: Sized;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0277]: the trait bound `U32: Clone` is not satisfied
-  --> $DIR/feature-gate-generic_associated_types.rs:16:26
-   |
-LL |     type Pointer2<U32> = Box<U32>;
-   |                          ^^^^^^^^ the trait `Clone` is not implemented for `U32`
-   |
-help: consider restricting type parameter `U32`
-   |
-LL |     type Pointer2<U32: std::clone::Clone> = Box<U32>;
-   |                      +++++++++++++++++++
-
-error: aborting due to 8 previous errors
-
-Some errors have detailed explanations: E0277, E0658.
-For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.rs b/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.rs
index 258b8cd35c77..7842d44ac4f0 100644
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.rs
+++ b/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // This feature doesn't *currently* fire on any specific code; it's just a
 // behavior change. Future changes might.
 #[rustc_error] //~ the
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.stderr b/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.stderr
index 6a5eba38cacc..bb1622628dc1 100644
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.stderr
+++ b/src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.stderr
@@ -1,5 +1,5 @@
 error[E0658]: the `#[rustc_error]` attribute is just used for rustc unit tests and will never be stable
-  --> $DIR/feature-gate-generic_associated_types_extended.rs:5:1
+  --> $DIR/feature-gate-generic_associated_types_extended.rs:3:1
    |
 LL | #[rustc_error]
    | ^^^^^^^^^^^^^^
diff --git a/src/test/ui/feature-gates/feature-gate-let_else.rs b/src/test/ui/feature-gates/feature-gate-let_else.rs
deleted file mode 100644
index 3f04a9dabfd1..000000000000
--- a/src/test/ui/feature-gates/feature-gate-let_else.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-fn main() {
-    let Some(x) = Some(1) else { //~ ERROR `let...else` statements are unstable
-        return;
-    };
-}
diff --git a/src/test/ui/feature-gates/feature-gate-let_else.stderr b/src/test/ui/feature-gates/feature-gate-let_else.stderr
deleted file mode 100644
index 862526041546..000000000000
--- a/src/test/ui/feature-gates/feature-gate-let_else.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error[E0658]: `let...else` statements are unstable
-  --> $DIR/feature-gate-let_else.rs:2:5
-   |
-LL | /     let Some(x) = Some(1) else {
-LL | |         return;
-LL | |     };
-   | |______^
-   |
-   = note: see issue #87335 <https://github.com/rust-lang/rust/issues/87335> for more information
-   = help: add `#![feature(let_else)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.rs b/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.rs
index 29a6e1f8a016..9b646060adfd 100644
--- a/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.rs
+++ b/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.rs
@@ -21,7 +21,7 @@ fn main() {
         Foo::A => {}
         Foo::B => {}
     }
-    //~^^^^ ERROR non-exhaustive patterns: `C` not covered
+    //~^^^^ ERROR non-exhaustive patterns: `Foo::C` not covered
 
     match Foo::A {
         Foo::A => {}
diff --git a/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.stderr b/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.stderr
index dbeef6c2d2ae..3de08e215dad 100644
--- a/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.stderr
+++ b/src/test/ui/feature-gates/feature-gate-non_exhaustive_omitted_patterns_lint.stderr
@@ -99,11 +99,11 @@ LL |         #[warn(non_exhaustive_omitted_patterns)]
    = note: see issue #89554 <https://github.com/rust-lang/rust/issues/89554> for more information
    = help: add `#![feature(non_exhaustive_omitted_patterns_lint)]` to the crate attributes to enable
 
-error[E0004]: non-exhaustive patterns: `C` not covered
+error[E0004]: non-exhaustive patterns: `Foo::C` not covered
   --> $DIR/feature-gate-non_exhaustive_omitted_patterns_lint.rs:20:11
    |
 LL |     match Foo::A {
-   |           ^^^^^^ pattern `C` not covered
+   |           ^^^^^^ pattern `Foo::C` not covered
    |
 note: `Foo` defined here
   --> $DIR/feature-gate-non_exhaustive_omitted_patterns_lint.rs:12:15
@@ -116,7 +116,7 @@ LL |         A, B, C,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Foo::B => {}
-LL +         C => todo!()
+LL +         Foo::C => todo!()
    |
 
 error: aborting due to previous error; 10 warnings emitted
diff --git a/src/test/ui/feature-gates/feature-gate-raw-dylib-2.rs b/src/test/ui/feature-gates/feature-gate-raw-dylib-2.rs
index 0594b1384ec2..fc47a9061d3c 100644
--- a/src/test/ui/feature-gates/feature-gate-raw-dylib-2.rs
+++ b/src/test/ui/feature-gates/feature-gate-raw-dylib-2.rs
@@ -1,10 +1,11 @@
+// only-x86
 #[link(name = "foo")]
 extern "C" {
     #[link_ordinal(42)]
-    //~^ ERROR: the `#[link_ordinal]` attribute is an experimental feature
+    //~^ ERROR: `#[link_ordinal]` is unstable on x86
     fn foo();
     #[link_ordinal(5)]
-    //~^ ERROR: the `#[link_ordinal]` attribute is an experimental feature
+    //~^ ERROR: `#[link_ordinal]` is unstable on x86
     static mut imported_variable: i32;
 }
 
diff --git a/src/test/ui/feature-gates/feature-gate-raw-dylib-2.stderr b/src/test/ui/feature-gates/feature-gate-raw-dylib-2.stderr
index d39969b61cac..0e900760d245 100644
--- a/src/test/ui/feature-gates/feature-gate-raw-dylib-2.stderr
+++ b/src/test/ui/feature-gates/feature-gate-raw-dylib-2.stderr
@@ -1,5 +1,5 @@
-error[E0658]: the `#[link_ordinal]` attribute is an experimental feature
-  --> $DIR/feature-gate-raw-dylib-2.rs:3:5
+error[E0658]: `#[link_ordinal]` is unstable on x86
+  --> $DIR/feature-gate-raw-dylib-2.rs:4:5
    |
 LL |     #[link_ordinal(42)]
    |     ^^^^^^^^^^^^^^^^^^^
@@ -7,8 +7,8 @@ LL |     #[link_ordinal(42)]
    = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
    = help: add `#![feature(raw_dylib)]` to the crate attributes to enable
 
-error[E0658]: the `#[link_ordinal]` attribute is an experimental feature
-  --> $DIR/feature-gate-raw-dylib-2.rs:6:5
+error[E0658]: `#[link_ordinal]` is unstable on x86
+  --> $DIR/feature-gate-raw-dylib-2.rs:7:5
    |
 LL |     #[link_ordinal(5)]
    |     ^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.rs b/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.rs
index 33655cf8bdc7..295f502d6a3e 100644
--- a/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.rs
+++ b/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.rs
@@ -1,7 +1,7 @@
 // only-windows
 // only-x86
 #[link(name = "foo", kind = "raw-dylib", import_name_type = "decorated")]
-//~^ ERROR link kind `raw-dylib` is unstable
+//~^ ERROR link kind `raw-dylib` is unstable on x86
 //~| ERROR import name type is unstable
 extern "C" {}
 
diff --git a/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.stderr b/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.stderr
index be82dd119264..d6b165b7610a 100644
--- a/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.stderr
+++ b/src/test/ui/feature-gates/feature-gate-raw-dylib-import-name-type.stderr
@@ -1,4 +1,4 @@
-error[E0658]: link kind `raw-dylib` is unstable
+error[E0658]: link kind `raw-dylib` is unstable on x86
   --> $DIR/feature-gate-raw-dylib-import-name-type.rs:3:29
    |
 LL | #[link(name = "foo", kind = "raw-dylib", import_name_type = "decorated")]
diff --git a/src/test/ui/feature-gates/feature-gate-raw-dylib.rs b/src/test/ui/feature-gates/feature-gate-raw-dylib.rs
index f894f517b38d..291cca8fd257 100644
--- a/src/test/ui/feature-gates/feature-gate-raw-dylib.rs
+++ b/src/test/ui/feature-gates/feature-gate-raw-dylib.rs
@@ -1,6 +1,7 @@
 // only-windows
+// only-x86
 #[link(name = "foo", kind = "raw-dylib")]
-//~^ ERROR: link kind `raw-dylib` is unstable
+//~^ ERROR: link kind `raw-dylib` is unstable on x86
 extern "C" {}
 
 fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-raw-dylib.stderr b/src/test/ui/feature-gates/feature-gate-raw-dylib.stderr
index ca7a61f64134..f02241e4908c 100644
--- a/src/test/ui/feature-gates/feature-gate-raw-dylib.stderr
+++ b/src/test/ui/feature-gates/feature-gate-raw-dylib.stderr
@@ -1,5 +1,5 @@
-error[E0658]: link kind `raw-dylib` is unstable
-  --> $DIR/feature-gate-raw-dylib.rs:2:29
+error[E0658]: link kind `raw-dylib` is unstable on x86
+  --> $DIR/feature-gate-raw-dylib.rs:3:29
    |
 LL | #[link(name = "foo", kind = "raw-dylib")]
    |                             ^^^^^^^^^^^
diff --git a/src/test/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.rs b/src/test/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.rs
new file mode 100644
index 000000000000..637765fff11e
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.rs
@@ -0,0 +1,18 @@
+// edition:2021
+
+// async_fn_in_trait is not enough to allow use of RPITIT
+#![allow(incomplete_features)]
+#![feature(async_fn_in_trait)]
+
+trait Foo {
+    fn bar() -> impl Sized; //~ ERROR `impl Trait` only allowed in function and inherent method return types, not in trait method return
+    fn baz() -> Box<impl std::fmt::Display>; //~ ERROR `impl Trait` only allowed in function and inherent method return types, not in trait method return
+}
+
+// Both return_position_impl_trait_in_trait and async_fn_in_trait are required for this (see also
+// feature-gate-async_fn_in_trait.rs)
+trait AsyncFoo {
+    async fn bar() -> impl Sized; //~ ERROR `impl Trait` only allowed in function and inherent method return types, not in trait method return
+}
+
+fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.stderr b/src/test/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.stderr
new file mode 100644
index 000000000000..aeabed4a6ab6
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.stderr
@@ -0,0 +1,30 @@
+error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in trait method return
+  --> $DIR/feature-gate-return_position_impl_trait_in_trait.rs:8:17
+   |
+LL |     fn bar() -> impl Sized;
+   |                 ^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
+
+error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in trait method return
+  --> $DIR/feature-gate-return_position_impl_trait_in_trait.rs:9:21
+   |
+LL |     fn baz() -> Box<impl std::fmt::Display>;
+   |                     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
+
+error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in trait method return
+  --> $DIR/feature-gate-return_position_impl_trait_in_trait.rs:15:23
+   |
+LL |     async fn bar() -> impl Sized;
+   |                       ^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0562`.
diff --git a/src/test/ui/feature-gates/feature-gate-unix_sigpipe.rs b/src/test/ui/feature-gates/feature-gate-unix_sigpipe.rs
new file mode 100644
index 000000000000..46dc3f6cc17a
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-unix_sigpipe.rs
@@ -0,0 +1,4 @@
+#![crate_type = "bin"]
+
+#[unix_sigpipe = "inherit"] //~ the `#[unix_sigpipe]` attribute is an experimental feature
+fn main () {}
diff --git a/src/test/ui/feature-gates/feature-gate-unix_sigpipe.stderr b/src/test/ui/feature-gates/feature-gate-unix_sigpipe.stderr
new file mode 100644
index 000000000000..cf3284467f77
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-unix_sigpipe.stderr
@@ -0,0 +1,12 @@
+error[E0658]: the `#[unix_sigpipe]` attribute is an experimental feature
+  --> $DIR/feature-gate-unix_sigpipe.rs:3:1
+   |
+LL | #[unix_sigpipe = "inherit"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #97889 <https://github.com/rust-lang/rust/issues/97889> for more information
+   = help: add `#![feature(unix_sigpipe)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
index b7757740d9e3..0f7520ef7f8a 100644
--- a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
+++ b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
@@ -18,11 +18,8 @@ LL |     foo(*x);
    |         ^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `(dyn Foo + 'static)`
+   = note: all function arguments must have a statically known size
    = help: unsized fn params are gated as an unstable feature
-help: function arguments must have a statically known size, borrowed types always have a known size
-   |
-LL |     foo(&*x);
-   |         +
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr b/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr
index aed7f72c660d..a8f23f81dea0 100644
--- a/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr
+++ b/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr
@@ -5,6 +5,18 @@ LL | fn bar(x: x::Foo) -> y::Foo {
    |                      ------ expected `y::Foo` because of return type
 LL |     return x;
    |            ^ expected enum `y::Foo`, found enum `x::Foo`
+   |
+   = note: enum `x::Foo` and enum `y::Foo` have similar names, but are actually distinct types
+note: enum `x::Foo` is defined in module `crate::x` of the current crate
+  --> $DIR/fully-qualified-type-name2.rs:4:5
+   |
+LL |     pub enum Foo { }
+   |     ^^^^^^^^^^^^
+note: enum `y::Foo` is defined in module `crate::y` of the current crate
+  --> $DIR/fully-qualified-type-name2.rs:8:5
+   |
+LL |     pub enum Foo { }
+   |     ^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/function-pointer/sized-ret-with-binder.rs b/src/test/ui/function-pointer/sized-ret-with-binder.rs
new file mode 100644
index 000000000000..104ac4d222eb
--- /dev/null
+++ b/src/test/ui/function-pointer/sized-ret-with-binder.rs
@@ -0,0 +1,15 @@
+// check-pass
+
+#![feature(unboxed_closures)]
+
+fn is_fn<T: for<'a> Fn<(&'a (),)>>() {}
+fn is_fn2<T: for<'a, 'b> Fn<(&'a &'b (),)>>() {}
+
+struct Outlives<'a, 'b>(std::marker::PhantomData<&'a &'b ()>);
+
+fn main() {
+    is_fn::<for<'a> fn(&'a ()) -> &'a ()>();
+    is_fn::<for<'a> fn(&'a ()) -> &'a dyn std::fmt::Debug>();
+    is_fn2::<for<'a, 'b> fn(&'a &'b ()) -> Outlives<'a, 'b>>();
+    is_fn2::<for<'a, 'b> fn(&'a &'b ()) -> (&'a (), &'a ())>();
+}
diff --git a/src/test/ui/function-pointer/unsized-ret.rs b/src/test/ui/function-pointer/unsized-ret.rs
new file mode 100644
index 000000000000..60af5769d6dd
--- /dev/null
+++ b/src/test/ui/function-pointer/unsized-ret.rs
@@ -0,0 +1,14 @@
+#![feature(fn_traits)]
+#![feature(unboxed_closures)]
+
+fn foo<F: Fn<T>, T>(f: Option<F>, t: T) {
+    let y = (f.unwrap()).call(t);
+}
+
+fn main() {
+    foo::<fn() -> str, _>(None, ());
+    //~^ ERROR the size for values of type `str` cannot be known at compilation time
+
+    foo::<for<'a> fn(&'a ()) -> (dyn std::fmt::Display + 'a), _>(None, (&(),));
+    //~^ ERROR the size for values of type `(dyn std::fmt::Display + 'a)` cannot be known at compilation time
+}
diff --git a/src/test/ui/function-pointer/unsized-ret.stderr b/src/test/ui/function-pointer/unsized-ret.stderr
new file mode 100644
index 000000000000..bec3e2aa3fe6
--- /dev/null
+++ b/src/test/ui/function-pointer/unsized-ret.stderr
@@ -0,0 +1,35 @@
+error[E0277]: the size for values of type `str` cannot be known at compilation time
+  --> $DIR/unsized-ret.rs:9:27
+   |
+LL |     foo::<fn() -> str, _>(None, ());
+   |     --------------------- ^^^^ doesn't have a size known at compile-time
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `fn() -> str`, the trait `Sized` is not implemented for `str`
+   = note: required because it appears within the type `fn() -> str`
+note: required by a bound in `foo`
+  --> $DIR/unsized-ret.rs:4:11
+   |
+LL | fn foo<F: Fn<T>, T>(f: Option<F>, t: T) {
+   |           ^^^^^ required by this bound in `foo`
+
+error[E0277]: the size for values of type `(dyn std::fmt::Display + 'a)` cannot be known at compilation time
+  --> $DIR/unsized-ret.rs:12:66
+   |
+LL |     foo::<for<'a> fn(&'a ()) -> (dyn std::fmt::Display + 'a), _>(None, (&(),));
+   |     ------------------------------------------------------------ ^^^^ doesn't have a size known at compile-time
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: within `for<'a> fn(&'a ()) -> (dyn std::fmt::Display + 'a)`, the trait `for<'a> Sized` is not implemented for `(dyn std::fmt::Display + 'a)`
+   = note: required because it appears within the type `for<'a> fn(&'a ()) -> (dyn std::fmt::Display + 'a)`
+note: required by a bound in `foo`
+  --> $DIR/unsized-ret.rs:4:11
+   |
+LL | fn foo<F: Fn<T>, T>(f: Option<F>, t: T) {
+   |           ^^^^^ required by this bound in `foo`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generator/clone-impl-async.rs b/src/test/ui/generator/clone-impl-async.rs
new file mode 100644
index 000000000000..83c51526b7b0
--- /dev/null
+++ b/src/test/ui/generator/clone-impl-async.rs
@@ -0,0 +1,71 @@
+// edition:2021
+// gate-test-generator_clone
+// Verifies that feature(generator_clone) doesn't allow async blocks to be cloned/copied.
+
+#![feature(generators, generator_clone)]
+
+use std::future::ready;
+
+struct NonClone;
+
+fn main() {
+    let inner_non_clone = async {
+        let non_clone = NonClone;
+        let () = ready(()).await;
+        drop(non_clone);
+    };
+    check_copy(&inner_non_clone);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+    check_clone(&inner_non_clone);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+
+    let non_clone = NonClone;
+    let outer_non_clone = async move {
+        drop(non_clone);
+    };
+    check_copy(&outer_non_clone);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+    check_clone(&outer_non_clone);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+
+    let maybe_copy_clone = async move {};
+    check_copy(&maybe_copy_clone);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+    check_clone(&maybe_copy_clone);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+
+    let inner_non_clone_fn = the_inner_non_clone_fn();
+    check_copy(&inner_non_clone_fn);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+    check_clone(&inner_non_clone_fn);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+
+    let outer_non_clone_fn = the_outer_non_clone_fn(NonClone);
+    check_copy(&outer_non_clone_fn);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+    check_clone(&outer_non_clone_fn);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+
+    let maybe_copy_clone_fn = the_maybe_copy_clone_fn();
+    check_copy(&maybe_copy_clone_fn);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+    check_clone(&maybe_copy_clone_fn);
+    //~^ ERROR the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+}
+
+async fn the_inner_non_clone_fn() {
+    let non_clone = NonClone;
+    let () = ready(()).await;
+    drop(non_clone);
+}
+
+async fn the_outer_non_clone_fn(non_clone: NonClone) {
+    let () = ready(()).await;
+    drop(non_clone);
+}
+
+async fn the_maybe_copy_clone_fn() {
+}
+
+fn check_copy<T: Copy>(_x: &T) {}
+fn check_clone<T: Clone>(_x: &T) {}
diff --git a/src/test/ui/generator/clone-impl-async.stderr b/src/test/ui/generator/clone-impl-async.stderr
new file mode 100644
index 000000000000..cbb58d2af18e
--- /dev/null
+++ b/src/test/ui/generator/clone-impl-async.stderr
@@ -0,0 +1,171 @@
+error[E0277]: the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+  --> $DIR/clone-impl-async.rs:17:16
+   |
+LL |     check_copy(&inner_non_clone);
+   |     ---------- ^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-async.rs:70:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+  --> $DIR/clone-impl-async.rs:19:17
+   |
+LL |     check_clone(&inner_non_clone);
+   |     ----------- ^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-async.rs:71:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+  --> $DIR/clone-impl-async.rs:26:16
+   |
+LL |     check_copy(&outer_non_clone);
+   |     ---------- ^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-async.rs:70:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+  --> $DIR/clone-impl-async.rs:28:17
+   |
+LL |     check_clone(&outer_non_clone);
+   |     ----------- ^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-async.rs:71:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+  --> $DIR/clone-impl-async.rs:32:16
+   |
+LL |     check_copy(&maybe_copy_clone);
+   |     ---------- ^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-async.rs:70:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+  --> $DIR/clone-impl-async.rs:34:17
+   |
+LL |     check_clone(&maybe_copy_clone);
+   |     ----------- ^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-async.rs:71:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+  --> $DIR/clone-impl-async.rs:38:16
+   |
+LL |     check_copy(&inner_non_clone_fn);
+   |     ---------- ^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-async.rs:70:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+  --> $DIR/clone-impl-async.rs:40:17
+   |
+LL |     check_clone(&inner_non_clone_fn);
+   |     ----------- ^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-async.rs:71:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+  --> $DIR/clone-impl-async.rs:44:16
+   |
+LL |     check_copy(&outer_non_clone_fn);
+   |     ---------- ^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-async.rs:70:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+  --> $DIR/clone-impl-async.rs:46:17
+   |
+LL |     check_clone(&outer_non_clone_fn);
+   |     ----------- ^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-async.rs:71:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Copy` is not satisfied
+  --> $DIR/clone-impl-async.rs:50:16
+   |
+LL |     check_copy(&maybe_copy_clone_fn);
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-async.rs:70:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `impl Future<Output = ()>: Clone` is not satisfied
+  --> $DIR/clone-impl-async.rs:52:17
+   |
+LL |     check_clone(&maybe_copy_clone_fn);
+   |     ----------- ^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `impl Future<Output = ()>`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-async.rs:71:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error: aborting due to 12 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generator/clone-impl-static.rs b/src/test/ui/generator/clone-impl-static.rs
new file mode 100644
index 000000000000..55ed0f281e05
--- /dev/null
+++ b/src/test/ui/generator/clone-impl-static.rs
@@ -0,0 +1,17 @@
+// gate-test-generator_clone
+// Verifies that static generators cannot be cloned/copied.
+
+#![feature(generators, generator_clone)]
+
+fn main() {
+    let gen = static move || {
+        yield;
+    };
+    check_copy(&gen);
+    //~^ ERROR Copy` is not satisfied
+    check_clone(&gen);
+    //~^ ERROR Clone` is not satisfied
+}
+
+fn check_copy<T: Copy>(_x: &T) {}
+fn check_clone<T: Clone>(_x: &T) {}
diff --git a/src/test/ui/generator/clone-impl-static.stderr b/src/test/ui/generator/clone-impl-static.stderr
new file mode 100644
index 000000000000..cbadf6f156a9
--- /dev/null
+++ b/src/test/ui/generator/clone-impl-static.stderr
@@ -0,0 +1,31 @@
+error[E0277]: the trait bound `[static generator@$DIR/clone-impl-static.rs:7:15: 7:29]: Copy` is not satisfied
+  --> $DIR/clone-impl-static.rs:10:16
+   |
+LL |     check_copy(&gen);
+   |     ---------- ^^^^ the trait `Copy` is not implemented for `[static generator@$DIR/clone-impl-static.rs:7:15: 7:29]`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl-static.rs:16:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `[static generator@$DIR/clone-impl-static.rs:7:15: 7:29]: Clone` is not satisfied
+  --> $DIR/clone-impl-static.rs:12:17
+   |
+LL |     check_clone(&gen);
+   |     ----------- ^^^^ the trait `Clone` is not implemented for `[static generator@$DIR/clone-impl-static.rs:7:15: 7:29]`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl-static.rs:17:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generator/clone-impl.rs b/src/test/ui/generator/clone-impl.rs
new file mode 100644
index 000000000000..cbfd65a53099
--- /dev/null
+++ b/src/test/ui/generator/clone-impl.rs
@@ -0,0 +1,73 @@
+// gate-test-generator_clone
+// Verifies that non-static generators can be cloned/copied if all their upvars and locals held
+// across awaits can be cloned/copied.
+
+#![feature(generators, generator_clone)]
+
+struct NonClone;
+
+fn main() {
+    let copyable: u32 = 123;
+    let clonable_0: Vec<u32> = Vec::new();
+    let clonable_1: Vec<u32> = Vec::new();
+    let non_clonable: NonClone = NonClone;
+
+    let gen_copy_0 = move || {
+        yield;
+        drop(copyable);
+    };
+    check_copy(&gen_copy_0);
+    check_clone(&gen_copy_0);
+    let gen_copy_1 = move || {
+        /*
+        let v = vec!['a'];
+        let n = NonClone;
+        drop(v);
+        drop(n);
+        */
+        yield;
+        let v = vec!['a'];
+        let n = NonClone;
+        drop(n);
+        drop(copyable);
+    };
+    check_copy(&gen_copy_1);
+    check_clone(&gen_copy_1);
+    let gen_clone_0 = move || {
+        let v = vec!['a'];
+        yield;
+        drop(v);
+        drop(clonable_0);
+    };
+    check_copy(&gen_clone_0);
+    //~^ ERROR the trait bound `Vec<u32>: Copy` is not satisfied
+    //~| ERROR the trait bound `Vec<char>: Copy` is not satisfied
+    check_clone(&gen_clone_0);
+    let gen_clone_1 = move || {
+        let v = vec!['a'];
+        /*
+        let n = NonClone;
+        drop(n);
+        */
+        yield;
+        let n = NonClone;
+        drop(n);
+        drop(v);
+        drop(clonable_1);
+    };
+    check_copy(&gen_clone_1);
+    //~^ ERROR the trait bound `Vec<u32>: Copy` is not satisfied
+    //~| ERROR the trait bound `Vec<char>: Copy` is not satisfied
+    check_clone(&gen_clone_1);
+    let gen_non_clone = move || {
+        yield;
+        drop(non_clonable);
+    };
+    check_copy(&gen_non_clone);
+    //~^ ERROR the trait bound `NonClone: Copy` is not satisfied
+    check_clone(&gen_non_clone);
+    //~^ ERROR the trait bound `NonClone: Clone` is not satisfied
+}
+
+fn check_copy<T: Copy>(_x: &T) {}
+fn check_clone<T: Clone>(_x: &T) {}
diff --git a/src/test/ui/generator/clone-impl.stderr b/src/test/ui/generator/clone-impl.stderr
new file mode 100644
index 000000000000..a92646b198cf
--- /dev/null
+++ b/src/test/ui/generator/clone-impl.stderr
@@ -0,0 +1,142 @@
+error[E0277]: the trait bound `Vec<u32>: Copy` is not satisfied in `[generator@$DIR/clone-impl.rs:36:23: 36:30]`
+  --> $DIR/clone-impl.rs:42:16
+   |
+LL |     let gen_clone_0 = move || {
+   |                       ------- within this `[generator@$DIR/clone-impl.rs:36:23: 36:30]`
+...
+LL |     check_copy(&gen_clone_0);
+   |                ^^^^^^^^^^^^ within `[generator@$DIR/clone-impl.rs:36:23: 36:30]`, the trait `Copy` is not implemented for `Vec<u32>`
+   |
+note: captured value does not implement `Copy`
+  --> $DIR/clone-impl.rs:40:14
+   |
+LL |         drop(clonable_0);
+   |              ^^^^^^^^^^ has type `Vec<u32>` which does not implement `Copy`
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl.rs:72:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `Vec<char>: Copy` is not satisfied in `[generator@$DIR/clone-impl.rs:36:23: 36:30]`
+  --> $DIR/clone-impl.rs:42:16
+   |
+LL |     let gen_clone_0 = move || {
+   |                       ------- within this `[generator@$DIR/clone-impl.rs:36:23: 36:30]`
+...
+LL |     check_copy(&gen_clone_0);
+   |                ^^^^^^^^^^^^ within `[generator@$DIR/clone-impl.rs:36:23: 36:30]`, the trait `Copy` is not implemented for `Vec<char>`
+   |
+note: generator does not implement `Copy` as this value is used across a yield
+  --> $DIR/clone-impl.rs:38:9
+   |
+LL |         let v = vec!['a'];
+   |             - has type `Vec<char>` which does not implement `Copy`
+LL |         yield;
+   |         ^^^^^ yield occurs here, with `v` maybe used later
+...
+LL |     };
+   |     - `v` is later dropped here
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl.rs:72:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `Vec<u32>: Copy` is not satisfied in `[generator@$DIR/clone-impl.rs:46:23: 46:30]`
+  --> $DIR/clone-impl.rs:58:16
+   |
+LL |     let gen_clone_1 = move || {
+   |                       ------- within this `[generator@$DIR/clone-impl.rs:46:23: 46:30]`
+...
+LL |     check_copy(&gen_clone_1);
+   |                ^^^^^^^^^^^^ within `[generator@$DIR/clone-impl.rs:46:23: 46:30]`, the trait `Copy` is not implemented for `Vec<u32>`
+   |
+note: captured value does not implement `Copy`
+  --> $DIR/clone-impl.rs:56:14
+   |
+LL |         drop(clonable_1);
+   |              ^^^^^^^^^^ has type `Vec<u32>` which does not implement `Copy`
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl.rs:72:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `Vec<char>: Copy` is not satisfied in `[generator@$DIR/clone-impl.rs:46:23: 46:30]`
+  --> $DIR/clone-impl.rs:58:16
+   |
+LL |     let gen_clone_1 = move || {
+   |                       ------- within this `[generator@$DIR/clone-impl.rs:46:23: 46:30]`
+...
+LL |     check_copy(&gen_clone_1);
+   |                ^^^^^^^^^^^^ within `[generator@$DIR/clone-impl.rs:46:23: 46:30]`, the trait `Copy` is not implemented for `Vec<char>`
+   |
+note: generator does not implement `Copy` as this value is used across a yield
+  --> $DIR/clone-impl.rs:52:9
+   |
+LL |         let v = vec!['a'];
+   |             - has type `Vec<char>` which does not implement `Copy`
+...
+LL |         yield;
+   |         ^^^^^ yield occurs here, with `v` maybe used later
+...
+LL |     };
+   |     - `v` is later dropped here
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl.rs:72:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+
+error[E0277]: the trait bound `NonClone: Copy` is not satisfied in `[generator@$DIR/clone-impl.rs:62:25: 62:32]`
+  --> $DIR/clone-impl.rs:66:16
+   |
+LL |     let gen_non_clone = move || {
+   |                         ------- within this `[generator@$DIR/clone-impl.rs:62:25: 62:32]`
+...
+LL |     check_copy(&gen_non_clone);
+   |                ^^^^^^^^^^^^^^ within `[generator@$DIR/clone-impl.rs:62:25: 62:32]`, the trait `Copy` is not implemented for `NonClone`
+   |
+note: captured value does not implement `Copy`
+  --> $DIR/clone-impl.rs:64:14
+   |
+LL |         drop(non_clonable);
+   |              ^^^^^^^^^^^^ has type `NonClone` which does not implement `Copy`
+note: required by a bound in `check_copy`
+  --> $DIR/clone-impl.rs:72:18
+   |
+LL | fn check_copy<T: Copy>(_x: &T) {}
+   |                  ^^^^ required by this bound in `check_copy`
+help: consider annotating `NonClone` with `#[derive(Copy)]`
+   |
+LL | #[derive(Copy)]
+   |
+
+error[E0277]: the trait bound `NonClone: Clone` is not satisfied in `[generator@$DIR/clone-impl.rs:62:25: 62:32]`
+  --> $DIR/clone-impl.rs:68:17
+   |
+LL |     let gen_non_clone = move || {
+   |                         ------- within this `[generator@$DIR/clone-impl.rs:62:25: 62:32]`
+...
+LL |     check_clone(&gen_non_clone);
+   |                 ^^^^^^^^^^^^^^ within `[generator@$DIR/clone-impl.rs:62:25: 62:32]`, the trait `Clone` is not implemented for `NonClone`
+   |
+note: captured value does not implement `Clone`
+  --> $DIR/clone-impl.rs:64:14
+   |
+LL |         drop(non_clonable);
+   |              ^^^^^^^^^^^^ has type `NonClone` which does not implement `Clone`
+note: required by a bound in `check_clone`
+  --> $DIR/clone-impl.rs:73:19
+   |
+LL | fn check_clone<T: Clone>(_x: &T) {}
+   |                   ^^^^^ required by this bound in `check_clone`
+help: consider annotating `NonClone` with `#[derive(Clone)]`
+   |
+LL | #[derive(Clone)]
+   |
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generator/panic-drops-resume.rs b/src/test/ui/generator/panic-drops-resume.rs
index 8d8eb6a97b15..4c3caeb14d67 100644
--- a/src/test/ui/generator/panic-drops-resume.rs
+++ b/src/test/ui/generator/panic-drops-resume.rs
@@ -2,8 +2,6 @@
 
 // run-pass
 // needs-unwind
-// ignore-wasm       no unwind support
-// ignore-emscripten no unwind support
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/generator/panic-drops.rs b/src/test/ui/generator/panic-drops.rs
index a9de4e7fc7d2..65001fd879bb 100644
--- a/src/test/ui/generator/panic-drops.rs
+++ b/src/test/ui/generator/panic-drops.rs
@@ -1,7 +1,6 @@
 // run-pass
 // needs-unwind
 
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/generator/panic-safe.rs b/src/test/ui/generator/panic-safe.rs
index 14a0c8dbaf1d..3db80bb58215 100644
--- a/src/test/ui/generator/panic-safe.rs
+++ b/src/test/ui/generator/panic-safe.rs
@@ -1,7 +1,6 @@
 // run-pass
 // needs-unwind
 
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/generator/resume-after-return.rs b/src/test/ui/generator/resume-after-return.rs
index 538609b981ad..01a059a161ce 100644
--- a/src/test/ui/generator/resume-after-return.rs
+++ b/src/test/ui/generator/resume-after-return.rs
@@ -1,7 +1,6 @@
 // run-pass
 // needs-unwind
 
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/generator/size-moved-locals.rs b/src/test/ui/generator/size-moved-locals.rs
index 3c756a86fc5a..601a31418287 100644
--- a/src/test/ui/generator/size-moved-locals.rs
+++ b/src/test/ui/generator/size-moved-locals.rs
@@ -12,6 +12,7 @@
 // edition:2018
 // ignore-wasm32 issue #62807
 // ignore-asmjs issue #62807
+// needs-unwind Size of Closures change on panic=abort
 
 #![feature(generators, generator_trait)]
 
diff --git a/src/test/ui/generic-associated-types/anonymize-bound-vars.rs b/src/test/ui/generic-associated-types/anonymize-bound-vars.rs
index 1ec9c69989a7..eb7a12412c6b 100644
--- a/src/test/ui/generic-associated-types/anonymize-bound-vars.rs
+++ b/src/test/ui/generic-associated-types/anonymize-bound-vars.rs
@@ -1,7 +1,6 @@
 // check-pass
 //
 // regression test for #98702
-#![feature(generic_associated_types)]
 
 trait Foo {
     type Assoc<T>;
diff --git a/src/test/ui/generic-associated-types/auxiliary/foo_defn.rs b/src/test/ui/generic-associated-types/auxiliary/foo_defn.rs
index 0e8e14852d9d..21a9b3b89a8d 100644
--- a/src/test/ui/generic-associated-types/auxiliary/foo_defn.rs
+++ b/src/test/ui/generic-associated-types/auxiliary/foo_defn.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 use std::{future::Future, pin::Pin};
 
 pub trait Foo {
diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-1.rs b/src/test/ui/generic-associated-types/bugs/hrtb-implied-1.rs
new file mode 100644
index 000000000000..719d1bd5a4c7
--- /dev/null
+++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-1.rs
@@ -0,0 +1,35 @@
+// check-fail
+// known-bug
+
+// This gives us problems because `for<'a> I::Item<'a>: Debug` should mean "for
+// all 'a where I::Item<'a> is WF", but really means "for all 'a possible"
+
+use std::fmt::Debug;
+
+pub trait LendingIterator {
+    type Item<'this>
+    where
+        Self: 'this;
+}
+
+pub struct WindowsMut<'x> {
+    slice: &'x (),
+}
+
+impl<'y> LendingIterator for WindowsMut<'y> {
+    type Item<'this> = &'this mut () where 'y: 'this;
+}
+
+fn print_items<I>(_iter: I)
+where
+    I: LendingIterator,
+    for<'a> I::Item<'a>: Debug,
+{
+}
+
+fn main() {
+    let slice = &mut ();
+    //~^ temporary value dropped while borrowed
+    let windows = WindowsMut { slice };
+    print_items::<WindowsMut<'_>>(windows);
+}
diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-1.stderr b/src/test/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
new file mode 100644
index 000000000000..414999881d47
--- /dev/null
+++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
@@ -0,0 +1,20 @@
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/hrtb-implied-1.rs:31:22
+   |
+LL |     let slice = &mut ();
+   |                      ^^ creates a temporary which is freed while still in use
+...
+LL |     print_items::<WindowsMut<'_>>(windows);
+   |     -------------------------------------- argument requires that borrow lasts for `'static`
+LL | }
+   | - temporary value is freed at the end of this statement
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/hrtb-implied-1.rs:26:26
+   |
+LL |     for<'a> I::Item<'a>: Debug,
+   |                          ^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0716`.
diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs
new file mode 100644
index 000000000000..8e6c5348e71c
--- /dev/null
+++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.rs
@@ -0,0 +1,40 @@
+// check-fail
+// known-bug
+
+// This gives us problems because `for<'a> I::Item<'a>: Debug` should mean "for
+// all 'a where I::Item<'a> is WF", but really means "for all 'a possible"
+
+trait LendingIterator: Sized {
+    type Item<'a>
+    where
+        Self: 'a;
+    fn next(&mut self) -> Self::Item<'_>;
+}
+fn fails<I: LendingIterator, F>(iter: &mut I, f: F) -> bool
+where
+    F: FnMut(I::Item<'_>),
+{
+    let mut iter2 = Eat(iter, f);
+    let _next = iter2.next();
+    //~^ borrowed data escapes
+    true
+}
+impl<I: LendingIterator> LendingIterator for &mut I {
+    type Item<'a> = I::Item<'a> where Self:'a;
+    fn next(&mut self) -> Self::Item<'_> {
+        (**self).next()
+    }
+}
+
+struct Eat<I, F>(I, F);
+impl<I: LendingIterator, F> Iterator for Eat<I, F>
+where
+    F: FnMut(I::Item<'_>),
+{
+    type Item = ();
+    fn next(&mut self) -> Option<Self::Item> {
+        None
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr
new file mode 100644
index 000000000000..1ee270398de4
--- /dev/null
+++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-2.stderr
@@ -0,0 +1,22 @@
+error[E0521]: borrowed data escapes outside of function
+  --> $DIR/hrtb-implied-2.rs:18:17
+   |
+LL | fn fails<I: LendingIterator, F>(iter: &mut I, f: F) -> bool
+   |                                 ----  - let's call the lifetime of this reference `'1`
+   |                                 |
+   |                                 `iter` is a reference that is only valid in the function body
+...
+LL |     let _next = iter2.next();
+   |                 ^^^^^^^^^^^^
+   |                 |
+   |                 `iter` escapes the function body here
+   |                 argument requires that `'1` must outlive `'static`
+   |
+   = note: requirement occurs because of a mutable reference to `Eat<&mut I, F>`
+   = note: mutable references are invariant over their type parameter
+   = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
+   = note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs
new file mode 100644
index 000000000000..bc9e6c8aea85
--- /dev/null
+++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.rs
@@ -0,0 +1,23 @@
+trait LendingIterator {
+    type Item<'a>
+    where
+        Self: 'a;
+}
+
+impl LendingIterator for &str {
+    type Item<'a> = () where Self:'a;
+}
+
+fn trivial_bound<I>(_: I)
+where
+    I: LendingIterator,
+    for<'a> I::Item<'a>: Sized,
+{
+}
+
+fn fails(iter: &str) {
+    trivial_bound(iter);
+    //~^ borrowed data escapes
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr
new file mode 100644
index 000000000000..c67e02437cd8
--- /dev/null
+++ b/src/test/ui/generic-associated-types/bugs/hrtb-implied-3.stderr
@@ -0,0 +1,22 @@
+error[E0521]: borrowed data escapes outside of function
+  --> $DIR/hrtb-implied-3.rs:19:5
+   |
+LL | fn fails(iter: &str) {
+   |          ----  - let's call the lifetime of this reference `'1`
+   |          |
+   |          `iter` is a reference that is only valid in the function body
+LL |     trivial_bound(iter);
+   |     ^^^^^^^^^^^^^^^^^^^
+   |     |
+   |     `iter` escapes the function body here
+   |     argument requires that `'1` must outlive `'static`
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/hrtb-implied-3.rs:14:26
+   |
+LL |     for<'a> I::Item<'a>: Sized,
+   |                          ^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/generic-associated-types/bugs/issue-80626.rs b/src/test/ui/generic-associated-types/bugs/issue-80626.rs
index 14f27aff1ccd..f6aa6b36e13d 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-80626.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-80626.rs
@@ -3,8 +3,6 @@
 
 // This should pass, but it requires `Sized` to be coinductive.
 
-#![feature(generic_associated_types)]
-
 trait Allocator {
     type Allocated<T>;
 }
diff --git a/src/test/ui/generic-associated-types/bugs/issue-80626.stderr b/src/test/ui/generic-associated-types/bugs/issue-80626.stderr
index 487b83dfa3fc..9a0f332ed473 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-80626.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-80626.stderr
@@ -1,11 +1,11 @@
 error[E0275]: overflow evaluating the requirement `LinkedList<A>: Sized`
-  --> $DIR/issue-80626.rs:14:10
+  --> $DIR/issue-80626.rs:12:10
    |
 LL |     Next(A::Allocated<Self>)
    |          ^^^^^^^^^^^^^^^^^^
    |
 note: required by a bound in `Allocator::Allocated`
-  --> $DIR/issue-80626.rs:9:20
+  --> $DIR/issue-80626.rs:7:20
    |
 LL |     type Allocated<T>;
    |                    ^ required by this bound in `Allocator::Allocated`
diff --git a/src/test/ui/generic-associated-types/bugs/issue-86218.stderr b/src/test/ui/generic-associated-types/bugs/issue-86218.stderr
deleted file mode 100644
index fbf1c8f95fec..000000000000
--- a/src/test/ui/generic-associated-types/bugs/issue-86218.stderr
+++ /dev/null
@@ -1,23 +0,0 @@
-error[E0477]: the type `<() as Yay<&'a ()>>::InnerStream<'s>` does not fulfill the required lifetime
-  --> $DIR/issue-86218.rs:23:28
-   |
-LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
-   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: type must outlive the lifetime `'s` as defined here as required by this binding
-  --> $DIR/issue-86218.rs:23:22
-   |
-LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
-   |                      ^^
-
-error: unconstrained opaque type
-  --> $DIR/issue-86218.rs:23:28
-   |
-LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
-   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `InnerStream` must be used in combination with a concrete type within the same module
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0477`.
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87735.rs b/src/test/ui/generic-associated-types/bugs/issue-87735.rs
index 0844d84c34fd..80737a79899b 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87735.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-87735.rs
@@ -3,8 +3,6 @@
 
 // This should pass, but we need an extension of implied bounds (probably).
 
-#![feature(generic_associated_types)]
-
 pub trait AsRef2 {
   type Output<'a> where Self: 'a;
 
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87735.stderr b/src/test/ui/generic-associated-types/bugs/issue-87735.stderr
index 0a18b5f0cbda..ebe2054ce5ef 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87735.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-87735.stderr
@@ -1,5 +1,5 @@
 error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-87735.rs:27:13
+  --> $DIR/issue-87735.rs:25:13
    |
 LL | impl<'b, T, U> AsRef2 for Foo<T>
    |             ^ unconstrained type parameter
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87755.rs b/src/test/ui/generic-associated-types/bugs/issue-87755.rs
index efa487d624fd..cda722d2f0c7 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87755.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-87755.rs
@@ -3,8 +3,6 @@
 
 // This should pass.
 
-#![feature(generic_associated_types)]
-
 use std::fmt::Debug;
 
 trait Foo {
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87755.stderr b/src/test/ui/generic-associated-types/bugs/issue-87755.stderr
index 5d1aff0117c1..5e94db9b0c00 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87755.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-87755.stderr
@@ -1,5 +1,5 @@
 error[E0275]: overflow evaluating the requirement `<Bar as Foo>::Ass == _`
-  --> $DIR/issue-87755.rs:18:16
+  --> $DIR/issue-87755.rs:16:16
    |
 LL |     type Ass = Bar;
    |                ^^^
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87803.rs b/src/test/ui/generic-associated-types/bugs/issue-87803.rs
index a8a111c99ef7..56237e387ef3 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87803.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-87803.rs
@@ -4,8 +4,6 @@
 // This should pass, but using a type alias vs a reference directly
 // changes late-bound -> early-bound.
 
-#![feature(generic_associated_types)]
-
 trait Scanner {
     type Input<'a>;
     type Token<'a>;
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87803.stderr b/src/test/ui/generic-associated-types/bugs/issue-87803.stderr
index c81c051d32a8..fe2abdedbf37 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87803.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-87803.stderr
@@ -1,5 +1,5 @@
 error[E0195]: lifetime parameters or bounds on method `scan` do not match the trait declaration
-  --> $DIR/issue-87803.rs:22:12
+  --> $DIR/issue-87803.rs:20:12
    |
 LL |     fn scan<'a>(&mut self, i : Self::Input<'a>) -> Self::Token<'a>;
    |            ---- lifetimes in impl do not match this method in trait
diff --git a/src/test/ui/generic-associated-types/bugs/issue-88382.rs b/src/test/ui/generic-associated-types/bugs/issue-88382.rs
index 5493b9b93913..8f8cc4523a20 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-88382.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-88382.rs
@@ -3,8 +3,6 @@
 
 // This should pass, but has a missed normalization due to HRTB.
 
-#![feature(generic_associated_types)]
-
 trait Iterable {
     type Iterator<'a> where Self: 'a;
     fn iter(&self) -> Self::Iterator<'_>;
diff --git a/src/test/ui/generic-associated-types/bugs/issue-88382.stderr b/src/test/ui/generic-associated-types/bugs/issue-88382.stderr
index 7210895b79bc..a9a70bb7130c 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-88382.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-88382.stderr
@@ -1,5 +1,5 @@
 error[E0631]: type mismatch in function arguments
-  --> $DIR/issue-88382.rs:28:40
+  --> $DIR/issue-88382.rs:26:40
    |
 LL |     do_something(SomeImplementation(), test);
    |     ------------                       ^^^^ expected due to this
@@ -9,10 +9,10 @@ LL |     do_something(SomeImplementation(), test);
 LL | fn test<'a, I: Iterable>(_: &mut I::Iterator<'a>) {}
    | ------------------------------------------------- found signature defined here
    |
-   = note: expected function signature `for<'r> fn(&'r mut std::iter::Empty<usize>) -> _`
-              found function signature `for<'a, 'r> fn(&'r mut <_ as Iterable>::Iterator<'a>) -> _`
+   = note: expected function signature `for<'a> fn(&'a mut std::iter::Empty<usize>) -> _`
+              found function signature `for<'a, 'b> fn(&'b mut <_ as Iterable>::Iterator<'a>) -> _`
 note: required by a bound in `do_something`
-  --> $DIR/issue-88382.rs:22:48
+  --> $DIR/issue-88382.rs:20:48
    |
 LL | fn do_something<I: Iterable>(i: I, mut f: impl for<'a> Fn(&mut I::Iterator<'a>)) {
    |                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `do_something`
diff --git a/src/test/ui/generic-associated-types/bugs/issue-88460.rs b/src/test/ui/generic-associated-types/bugs/issue-88460.rs
index f1c3b2269158..224e696ad2c9 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-88460.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-88460.rs
@@ -3,8 +3,6 @@
 
 // This should pass, but has a missed normalization due to HRTB.
 
-#![feature(generic_associated_types)]
-
 pub trait Marker {}
 
 pub trait Trait {
diff --git a/src/test/ui/generic-associated-types/bugs/issue-88460.stderr b/src/test/ui/generic-associated-types/bugs/issue-88460.stderr
index 8193f491e69e..6612c4b49446 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-88460.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-88460.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `for<'a> <_ as Trait>::Assoc<'a>: Marker` is not satisfied
-  --> $DIR/issue-88460.rs:30:10
+  --> $DIR/issue-88460.rs:28:10
    |
 LL |     test(Foo);
    |     ---- ^^^ the trait `for<'a> Marker` is not implemented for `<_ as Trait>::Assoc<'a>`
@@ -8,7 +8,7 @@ LL |     test(Foo);
    |
    = help: the trait `Marker` is implemented for `()`
 note: required by a bound in `test`
-  --> $DIR/issue-88460.rs:17:27
+  --> $DIR/issue-88460.rs:15:27
    |
 LL | fn test<T>(value: T)
    |    ---- required by a bound in this
diff --git a/src/test/ui/generic-associated-types/bugs/issue-88526.rs b/src/test/ui/generic-associated-types/bugs/issue-88526.rs
index 15363ad04bfe..99397744fa65 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-88526.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-88526.rs
@@ -3,8 +3,6 @@
 
 // This should pass, but requires more logic.
 
-#![feature(generic_associated_types)]
-
 trait A {
     type I<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/bugs/issue-88526.stderr b/src/test/ui/generic-associated-types/bugs/issue-88526.stderr
index 127c889bf715..56857c6550bd 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-88526.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-88526.stderr
@@ -1,5 +1,5 @@
 error[E0207]: the type parameter `I` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-88526.rs:27:13
+  --> $DIR/issue-88526.rs:25:13
    |
 LL | impl<'q, Q, I, F> A for TestB<Q, F>
    |             ^ unconstrained type parameter
diff --git a/src/test/ui/generic-associated-types/bugs/issue-89008.rs b/src/test/ui/generic-associated-types/bugs/issue-89008.rs
index 79c28b0d2217..012aa8df2fc3 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-89008.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-89008.rs
@@ -5,7 +5,6 @@
 // This should pass, but seems to run into a TAIT bug.
 
 #![feature(type_alias_impl_trait)]
-#![feature(generic_associated_types)]
 
 use std::future::Future;
 
diff --git a/src/test/ui/generic-associated-types/bugs/issue-89008.stderr b/src/test/ui/generic-associated-types/bugs/issue-89008.stderr
index 50844fdc14d9..3f72734efa1d 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-89008.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-89008.stderr
@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<Empty<_> as Stream>::Item == Repr`
-  --> $DIR/issue-89008.rs:39:43
+  --> $DIR/issue-89008.rs:38:43
    |
 LL |     fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {
    |                        ----               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `<Empty<_> as Stream>::Item == Repr`
@@ -7,7 +7,7 @@ LL |     fn line_stream<'a, Repr>(&'a self) -> Self::LineStreamFut<'a, Repr> {
    |                        this type parameter
    |
 note: expected this to be `()`
-  --> $DIR/issue-89008.rs:18:17
+  --> $DIR/issue-89008.rs:17:17
    |
 LL |     type Item = ();
    |                 ^^
diff --git a/src/test/ui/generic-associated-types/issue-91762.rs b/src/test/ui/generic-associated-types/bugs/issue-91762.rs
similarity index 86%
rename from src/test/ui/generic-associated-types/issue-91762.rs
rename to src/test/ui/generic-associated-types/bugs/issue-91762.rs
index b259a3c6e06b..796935cc06f5 100644
--- a/src/test/ui/generic-associated-types/issue-91762.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-91762.rs
@@ -1,13 +1,12 @@
 // check-fail
+// known-bug
 
-// FIXME(generic_associated_types): We almost certaintly want this to pass, but
+// We almost certaintly want this to pass, but
 // it's particularly difficult currently, because we need a way of specifying
 // that `<Self::Base as Functor>::With<T> = Self` without using that when we have
 // a `U`. See `https://github.com/rust-lang/rust/pull/92728` for a (hacky)
 // solution. This might be better to just wait for Chalk.
 
-#![feature(generic_associated_types)]
-
 pub trait Functor {
     type With<T>;
 
diff --git a/src/test/ui/generic-associated-types/issue-91762.stderr b/src/test/ui/generic-associated-types/bugs/issue-91762.stderr
similarity index 94%
rename from src/test/ui/generic-associated-types/issue-91762.stderr
rename to src/test/ui/generic-associated-types/bugs/issue-91762.stderr
index c2785fee387f..1272c8b8ae27 100644
--- a/src/test/ui/generic-associated-types/issue-91762.stderr
+++ b/src/test/ui/generic-associated-types/bugs/issue-91762.stderr
@@ -1,5 +1,5 @@
 error[E0282]: type annotations needed
-  --> $DIR/issue-91762.rs:25:15
+  --> $DIR/issue-91762.rs:24:15
    |
 LL |         ret = <Self::Base as Functor>::fmap(arg);
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the associated function `fmap`
diff --git a/src/test/ui/generic-associated-types/collections-project-default.rs b/src/test/ui/generic-associated-types/collections-project-default.rs
index 157e1b1d2957..e08aa18cf0f1 100644
--- a/src/test/ui/generic-associated-types/collections-project-default.rs
+++ b/src/test/ui/generic-associated-types/collections-project-default.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 // A Collection trait and collection families. Based on
diff --git a/src/test/ui/generic-associated-types/collections-project-default.stderr b/src/test/ui/generic-associated-types/collections-project-default.stderr
index 22fbc0271b48..5701017dc347 100644
--- a/src/test/ui/generic-associated-types/collections-project-default.stderr
+++ b/src/test/ui/generic-associated-types/collections-project-default.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/collections-project-default.rs:59:5
+  --> $DIR/collections-project-default.rs:58:5
    |
 LL | fn floatify_sibling<C>(ints: &C) -> <C as Collection<i32>>::Sibling<f32>
    |                                     ------------------------------------ expected `<C as Collection<i32>>::Sibling<f32>` because of return type
diff --git a/src/test/ui/generic-associated-types/collections.rs b/src/test/ui/generic-associated-types/collections.rs
index 1c00aa73feb9..15f429afb027 100644
--- a/src/test/ui/generic-associated-types/collections.rs
+++ b/src/test/ui/generic-associated-types/collections.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 // A Collection trait and collection families. Based on
diff --git a/src/test/ui/generic-associated-types/collectivity-regression.rs b/src/test/ui/generic-associated-types/collectivity-regression.rs
index fb7368439073..54154f9d1fc8 100644
--- a/src/test/ui/generic-associated-types/collectivity-regression.rs
+++ b/src/test/ui/generic-associated-types/collectivity-regression.rs
@@ -1,7 +1,5 @@
 // Regression test from https://github.com/rust-lang/rust/pull/98109
 
-#![feature(generic_associated_types)]
-
 pub trait Get {
     type Value<'a>
     where
diff --git a/src/test/ui/generic-associated-types/collectivity-regression.stderr b/src/test/ui/generic-associated-types/collectivity-regression.stderr
index a858dd7fddcd..1dbe1e2cb224 100644
--- a/src/test/ui/generic-associated-types/collectivity-regression.stderr
+++ b/src/test/ui/generic-associated-types/collectivity-regression.stderr
@@ -1,5 +1,5 @@
 error: `T` does not live long enough
-  --> $DIR/collectivity-regression.rs:15:5
+  --> $DIR/collectivity-regression.rs:13:5
    |
 LL | /     || {
 LL | |
diff --git a/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-1.rs b/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-1.rs
index afde5f37634b..c5f9a25a6ea9 100644
--- a/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-1.rs
+++ b/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-1.rs
@@ -1,5 +1,4 @@
 // run-pass
-#![feature(generic_associated_types)]
 
 // This test unsures that with_opt_const_param returns the
 // def_id of the N param in the Foo::Assoc GAT.
diff --git a/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-2.rs b/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-2.rs
index 51046be79b7e..cd7941ed9af7 100644
--- a/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-2.rs
+++ b/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-2.rs
@@ -1,5 +1,4 @@
 // run-pass
-#![feature(generic_associated_types)]
 
 // This test unsures that with_opt_const_param returns the
 // def_id of the N param in the Foo::Assoc GAT.
diff --git a/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-3.rs b/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-3.rs
index 457fe27b3ff3..db61fc08005b 100644
--- a/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-3.rs
+++ b/src/test/ui/generic-associated-types/const-generics-gat-in-trait-return-type-3.rs
@@ -1,5 +1,4 @@
 // run-pass
-#![feature(generic_associated_types)]
 
 // This test unsures that with_opt_const_param returns the
 // def_id of the N param in the Bar::Assoc GAT.
diff --git a/src/test/ui/generic-associated-types/const_params_have_right_type.rs b/src/test/ui/generic-associated-types/const_params_have_right_type.rs
index 6bed8e3aff97..d2cb12697e42 100644
--- a/src/test/ui/generic-associated-types/const_params_have_right_type.rs
+++ b/src/test/ui/generic-associated-types/const_params_have_right_type.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Trait {
     type Foo<const N: u8>;
 }
diff --git a/src/test/ui/generic-associated-types/const_params_have_right_type.stderr b/src/test/ui/generic-associated-types/const_params_have_right_type.stderr
index 89c993dee5e6..fdedd3bf5fbf 100644
--- a/src/test/ui/generic-associated-types/const_params_have_right_type.stderr
+++ b/src/test/ui/generic-associated-types/const_params_have_right_type.stderr
@@ -1,5 +1,5 @@
 error[E0053]: type `Foo` has an incompatible generic parameter for trait `Trait`
-  --> $DIR/const_params_have_right_type.rs:8:14
+  --> $DIR/const_params_have_right_type.rs:6:14
    |
 LL | trait Trait {
    |       -----
diff --git a/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.rs b/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.rs
index e315ee842180..c78a549970d8 100644
--- a/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.rs
+++ b/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.rs
@@ -1,7 +1,5 @@
 // Test that correct syntax is used in suggestion to constrain associated type
 
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<T>;
 }
diff --git a/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.stderr b/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.stderr
index 957ae5d29324..96c4330fec02 100644
--- a/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.stderr
+++ b/src/test/ui/generic-associated-types/constraint-assoc-type-suggestion.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/constraint-assoc-type-suggestion.rs:12:23
+  --> $DIR/constraint-assoc-type-suggestion.rs:10:23
    |
 LL |     let b: Vec<i32> = a;
    |            --------   ^ expected struct `Vec`, found associated type
diff --git a/src/test/ui/generic-associated-types/construct_with_other_type.rs b/src/test/ui/generic-associated-types/construct_with_other_type.rs
index 060804269aa7..5cb07f558834 100644
--- a/src/test/ui/generic-associated-types/construct_with_other_type.rs
+++ b/src/test/ui/generic-associated-types/construct_with_other_type.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // check-pass
 
 use std::ops::Deref;
diff --git a/src/test/ui/generic-associated-types/cross-crate-bounds.stderr b/src/test/ui/generic-associated-types/cross-crate-bounds.stderr
index c4009dd96251..c81cd7e7718c 100644
--- a/src/test/ui/generic-associated-types/cross-crate-bounds.stderr
+++ b/src/test/ui/generic-associated-types/cross-crate-bounds.stderr
@@ -5,7 +5,7 @@ LL |     type Bar = ();
    |                ^^ the trait `AsRef<()>` is not implemented for `()`
    |
 note: required by a bound in `foo_defn::Foo::Bar`
-  --> $DIR/auxiliary/foo_defn.rs:6:15
+  --> $DIR/auxiliary/foo_defn.rs:4:15
    |
 LL |     type Bar: AsRef<()>;
    |               ^^^^^^^^^ required by this bound in `foo_defn::Foo::Bar`
diff --git a/src/test/ui/generic-associated-types/elided-in-expr-position.rs b/src/test/ui/generic-associated-types/elided-in-expr-position.rs
index 482d0d5c00a6..e40093305c40 100644
--- a/src/test/ui/generic-associated-types/elided-in-expr-position.rs
+++ b/src/test/ui/generic-associated-types/elided-in-expr-position.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![allow(unused)]
 
 pub trait Trait  {
diff --git a/src/test/ui/generic-associated-types/elided-in-expr-position.stderr b/src/test/ui/generic-associated-types/elided-in-expr-position.stderr
index b395a1cfd8a6..20f35c3c1370 100644
--- a/src/test/ui/generic-associated-types/elided-in-expr-position.stderr
+++ b/src/test/ui/generic-associated-types/elided-in-expr-position.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `Trait::Assoc`
-  --> $DIR/elided-in-expr-position.rs:10:26
+  --> $DIR/elided-in-expr-position.rs:9:26
    |
 LL |     fn g(&self) -> Self::Assoc;
    |                          ^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/elided-in-expr-position.rs:5:10
+  --> $DIR/elided-in-expr-position.rs:4:10
    |
 LL |     type Assoc<'a> where Self: 'a;
    |          ^^^^^ --
@@ -15,13 +15,13 @@ LL |     fn g(&self) -> Self::Assoc<'a>;
    |                          ~~~~~~~~~
 
 error[E0107]: missing generics for associated type `Trait::Assoc`
-  --> $DIR/elided-in-expr-position.rs:32:26
+  --> $DIR/elided-in-expr-position.rs:31:26
    |
 LL |     fn g(&self) -> Self::Assoc {
    |                          ^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/elided-in-expr-position.rs:5:10
+  --> $DIR/elided-in-expr-position.rs:4:10
    |
 LL |     type Assoc<'a> where Self: 'a;
    |          ^^^^^ --
diff --git a/src/test/ui/generic-associated-types/empty_generics.rs b/src/test/ui/generic-associated-types/empty_generics.rs
index 772b7f2b4e30..964c2972d473 100644
--- a/src/test/ui/generic-associated-types/empty_generics.rs
+++ b/src/test/ui/generic-associated-types/empty_generics.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Foo {
     type Bar<,>;
     //~^ ERROR expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
diff --git a/src/test/ui/generic-associated-types/empty_generics.stderr b/src/test/ui/generic-associated-types/empty_generics.stderr
index ac22bfc0835b..b753181cf480 100644
--- a/src/test/ui/generic-associated-types/empty_generics.stderr
+++ b/src/test/ui/generic-associated-types/empty_generics.stderr
@@ -1,5 +1,5 @@
 error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
-  --> $DIR/empty_generics.rs:4:14
+  --> $DIR/empty_generics.rs:2:14
    |
 LL | trait Foo {
    |           - while parsing this item list starting here
diff --git a/src/test/ui/generic-associated-types/extended/lending_iterator.base.stderr b/src/test/ui/generic-associated-types/extended/lending_iterator.base.stderr
index 3da7794b3d2c..614c4a34c187 100644
--- a/src/test/ui/generic-associated-types/extended/lending_iterator.base.stderr
+++ b/src/test/ui/generic-associated-types/extended/lending_iterator.base.stderr
@@ -1,5 +1,5 @@
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/lending_iterator.rs:14:45
+  --> $DIR/lending_iterator.rs:13:45
    |
 LL |     fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
    |     ------------------------------------------------------------------------ definition of `from_iter` from trait
diff --git a/src/test/ui/generic-associated-types/extended/lending_iterator.rs b/src/test/ui/generic-associated-types/extended/lending_iterator.rs
index ede164766361..247761dd04bf 100644
--- a/src/test/ui/generic-associated-types/extended/lending_iterator.rs
+++ b/src/test/ui/generic-associated-types/extended/lending_iterator.rs
@@ -2,7 +2,6 @@
 //[base] check-fail
 //[extended] check-pass
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/extended/lending_iterator_2.base.stderr b/src/test/ui/generic-associated-types/extended/lending_iterator_2.base.stderr
index 6c2a624ca11d..f6b0b644e406 100644
--- a/src/test/ui/generic-associated-types/extended/lending_iterator_2.base.stderr
+++ b/src/test/ui/generic-associated-types/extended/lending_iterator_2.base.stderr
@@ -1,5 +1,5 @@
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/lending_iterator_2.rs:14:45
+  --> $DIR/lending_iterator_2.rs:13:45
    |
 LL |     fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
    |     ------------------------------------------------------------------------ definition of `from_iter` from trait
diff --git a/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs b/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs
index 3c4a2184db90..eb9c0456a1ee 100644
--- a/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs
+++ b/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs
@@ -2,7 +2,6 @@
 //[base] check-fail
 //[extended] check-pass
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature-2.rs b/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature-2.rs
deleted file mode 100644
index c1d68812e935..000000000000
--- a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature-2.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// rust-lang/rust#60654: Do not ICE on an attempt to use GATs that is
-// missing the feature gate.
-
-struct Foo;
-
-trait MyTrait {
-    type Item<T>;
-    //~^ ERROR generic associated types are unstable [E0658]
-}
-
-impl MyTrait for Foo {
-    type Item<T> = T;
-    //~^ ERROR generic associated types are unstable [E0658]
-}
-
-fn main() { }
diff --git a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature-2.stderr b/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature-2.stderr
deleted file mode 100644
index 34f536dbe8f6..000000000000
--- a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature-2.stderr
+++ /dev/null
@@ -1,21 +0,0 @@
-error[E0658]: generic associated types are unstable
-  --> $DIR/gat-dont-ice-on-absent-feature-2.rs:7:5
-   |
-LL |     type Item<T>;
-   |     ^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0658]: generic associated types are unstable
-  --> $DIR/gat-dont-ice-on-absent-feature-2.rs:12:5
-   |
-LL |     type Item<T> = T;
-   |     ^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature.rs b/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature.rs
deleted file mode 100644
index e8fc47d2a59f..000000000000
--- a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// rust-lang/rust#60654: Do not ICE on an attempt to use GATs that is
-// missing the feature gate.
-
-struct Foo;
-
-impl Iterator for Foo {
-    type Item<'b> = &'b Foo;
-    //~^ ERROR generic associated types are unstable [E0658]
-    //~| ERROR lifetime parameters or bounds on type `Item` do not match the trait declaration
-
-    fn next(&mut self) -> Option<Self::Item> {
-        None
-    }
-}
-
-fn main() { }
diff --git a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature.stderr b/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature.stderr
deleted file mode 100644
index ec36886f7b51..000000000000
--- a/src/test/ui/generic-associated-types/gat-dont-ice-on-absent-feature.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error[E0658]: generic associated types are unstable
-  --> $DIR/gat-dont-ice-on-absent-feature.rs:7:5
-   |
-LL |     type Item<'b> = &'b Foo;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error[E0195]: lifetime parameters or bounds on type `Item` do not match the trait declaration
-  --> $DIR/gat-dont-ice-on-absent-feature.rs:7:14
-   |
-LL |     type Item<'b> = &'b Foo;
-   |              ^^^^ lifetimes do not match type in trait
-
-error: aborting due to 2 previous errors
-
-Some errors have detailed explanations: E0195, E0658.
-For more information about an error, try `rustc --explain E0195`.
diff --git a/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.rs b/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.rs
index f542a7f545e0..86b164ba7d8a 100644
--- a/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.rs
+++ b/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
   type Y<'x>;
 }
diff --git a/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.stderr b/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.stderr
index 1792d8db292c..b77f10084c92 100644
--- a/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.stderr
+++ b/src/test/ui/generic-associated-types/gat-in-trait-path-undeclared-lifetime.stderr
@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'x`
-  --> $DIR/gat-in-trait-path-undeclared-lifetime.rs:8:35
+  --> $DIR/gat-in-trait-path-undeclared-lifetime.rs:6:35
    |
 LL |   fn _f(arg : Box<dyn for<'a> X<Y<'x> = &'a [u32]>>) {}
    |                                   ^^ undeclared lifetime
@@ -15,7 +15,7 @@ LL |   fn _f<'x>(arg : Box<dyn for<'a> X<Y<'x> = &'a [u32]>>) {}
    |        ++++
 
 error[E0582]: binding for associated type `Y` references lifetime `'a`, which does not appear in the trait input types
-  --> $DIR/gat-in-trait-path-undeclared-lifetime.rs:8:33
+  --> $DIR/gat-in-trait-path-undeclared-lifetime.rs:6:33
    |
 LL |   fn _f(arg : Box<dyn for<'a> X<Y<'x> = &'a [u32]>>) {}
    |                                 ^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/gat-in-trait-path.base.stderr b/src/test/ui/generic-associated-types/gat-in-trait-path.base.stderr
index c2054f64e2d6..fd54faaf37cb 100644
--- a/src/test/ui/generic-associated-types/gat-in-trait-path.base.stderr
+++ b/src/test/ui/generic-associated-types/gat-in-trait-path.base.stderr
@@ -1,11 +1,11 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/gat-in-trait-path.rs:27:17
+  --> $DIR/gat-in-trait-path.rs:26:17
    |
 LL | fn f(_arg : Box<dyn for<'a> Foo<A<'a> = &'a ()>>) {}
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/gat-in-trait-path.rs:11:10
+  --> $DIR/gat-in-trait-path.rs:10:10
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/gat-in-trait-path.rs b/src/test/ui/generic-associated-types/gat-in-trait-path.rs
index c82450ccff14..c55f5a726bdc 100644
--- a/src/test/ui/generic-associated-types/gat-in-trait-path.rs
+++ b/src/test/ui/generic-associated-types/gat-in-trait-path.rs
@@ -2,7 +2,6 @@
 //[base] check-fail
 //[extended] check-pass
 
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
diff --git a/src/test/ui/generic-associated-types/gat-incomplete-warning.rs b/src/test/ui/generic-associated-types/gat-incomplete-warning.rs
deleted file mode 100644
index 607ea1759888..000000000000
--- a/src/test/ui/generic-associated-types/gat-incomplete-warning.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-// run-pass
-
-#![feature(generic_associated_types)]
-
-fn main() {}
diff --git a/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.rs b/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.rs
index dbf7e02aeafc..d00c036fbd55 100644
--- a/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.rs
+++ b/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Foo {
     type F<'a>;
 
diff --git a/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.stderr b/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.stderr
index dad0dae6a44b..cb2b9f32bfe7 100644
--- a/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.stderr
+++ b/src/test/ui/generic-associated-types/gat-trait-path-generic-type-arg.stderr
@@ -1,5 +1,5 @@
 error[E0403]: the name `T1` is already used for a generic parameter in this item's generic parameters
-  --> $DIR/gat-trait-path-generic-type-arg.rs:11:12
+  --> $DIR/gat-trait-path-generic-type-arg.rs:9:12
    |
 LL | impl <T, T1> Foo for T {
    |          -- first use of `T1`
@@ -8,13 +8,13 @@ LL |     type F<T1> = &[u8];
    |            ^^ already used
 
 error[E0637]: `&` without an explicit lifetime name cannot be used here
-  --> $DIR/gat-trait-path-generic-type-arg.rs:11:18
+  --> $DIR/gat-trait-path-generic-type-arg.rs:9:18
    |
 LL |     type F<T1> = &[u8];
    |                  ^ explicit lifetime name needed here
 
 error[E0207]: the type parameter `T1` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/gat-trait-path-generic-type-arg.rs:9:10
+  --> $DIR/gat-trait-path-generic-type-arg.rs:7:10
    |
 LL | impl <T, T1> Foo for T {
    |          ^^ unconstrained type parameter
diff --git a/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.rs b/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.rs
index 9864787f0aa2..83b86f04a957 100644
--- a/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.rs
+++ b/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
   type Y<'a>;
 
diff --git a/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.stderr b/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.stderr
index aeb9238de81f..452dfefd1e3d 100644
--- a/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.stderr
+++ b/src/test/ui/generic-associated-types/gat-trait-path-missing-lifetime.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `X::Y`
-  --> $DIR/gat-trait-path-missing-lifetime.rs:10:20
+  --> $DIR/gat-trait-path-missing-lifetime.rs:8:20
    |
 LL |   fn foo<'a, T1: X<Y = T1>>(t : T1) -> T1::Y<'a> {
    |                    ^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/gat-trait-path-missing-lifetime.rs:4:8
+  --> $DIR/gat-trait-path-missing-lifetime.rs:2:8
    |
 LL |   type Y<'a>;
    |        ^ --
@@ -15,13 +15,13 @@ LL |   fn foo<'a, T1: X<Y<'a> = T1>>(t : T1) -> T1::Y<'a> {
    |                    ~~~~~
 
 error[E0107]: missing generics for associated type `X::Y`
-  --> $DIR/gat-trait-path-missing-lifetime.rs:10:20
+  --> $DIR/gat-trait-path-missing-lifetime.rs:8:20
    |
 LL |   fn foo<'a, T1: X<Y = T1>>(t : T1) -> T1::Y<'a> {
    |                    ^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/gat-trait-path-missing-lifetime.rs:4:8
+  --> $DIR/gat-trait-path-missing-lifetime.rs:2:8
    |
 LL |   type Y<'a>;
    |        ^ --
diff --git a/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.rs b/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.rs
index c55b0530c9da..9eb069637c68 100644
--- a/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.rs
+++ b/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
   type Y<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.stderr b/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.stderr
index 162214063e7d..e55a21e19f04 100644
--- a/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.stderr
+++ b/src/test/ui/generic-associated-types/gat-trait-path-parenthesised-args.stderr
@@ -1,11 +1,11 @@
 error: lifetime in trait object type must be followed by `+`
-  --> $DIR/gat-trait-path-parenthesised-args.rs:7:29
+  --> $DIR/gat-trait-path-parenthesised-args.rs:5:29
    |
 LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
    |                             ^^
 
 error: parenthesized generic arguments cannot be used in associated type constraints
-  --> $DIR/gat-trait-path-parenthesised-args.rs:7:27
+  --> $DIR/gat-trait-path-parenthesised-args.rs:5:27
    |
 LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
    |                           ^^^^^
@@ -16,7 +16,7 @@ LL | fn foo<'a>(arg: Box<dyn X<Y<'a> = &'a ()>>) {}
    |                            ~  ~
 
 error: parenthesized generic arguments cannot be used in associated type constraints
-  --> $DIR/gat-trait-path-parenthesised-args.rs:14:27
+  --> $DIR/gat-trait-path-parenthesised-args.rs:12:27
    |
 LL | fn bar<'a>(arg: Box<dyn X<Y() = ()>>) {}
    |                           ^--
@@ -24,13 +24,13 @@ LL | fn bar<'a>(arg: Box<dyn X<Y() = ()>>) {}
    |                            help: remove these parentheses
 
 error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
-  --> $DIR/gat-trait-path-parenthesised-args.rs:7:27
+  --> $DIR/gat-trait-path-parenthesised-args.rs:5:27
    |
 LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
    |                           ^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/gat-trait-path-parenthesised-args.rs:4:8
+  --> $DIR/gat-trait-path-parenthesised-args.rs:2:8
    |
 LL |   type Y<'a>;
    |        ^ --
@@ -40,7 +40,7 @@ LL | fn foo<'a>(arg: Box<dyn X<Y('a, 'a) = &'a ()>>) {}
    |                             +++
 
 error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/gat-trait-path-parenthesised-args.rs:7:27
+  --> $DIR/gat-trait-path-parenthesised-args.rs:5:27
    |
 LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
    |                           ^---- help: remove these generics
@@ -48,19 +48,19 @@ LL | fn foo<'a>(arg: Box<dyn X<Y('a) = &'a ()>>) {}
    |                           expected 0 generic arguments
    |
 note: associated type defined here, with 0 generic parameters
-  --> $DIR/gat-trait-path-parenthesised-args.rs:4:8
+  --> $DIR/gat-trait-path-parenthesised-args.rs:2:8
    |
 LL |   type Y<'a>;
    |        ^
 
 error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
-  --> $DIR/gat-trait-path-parenthesised-args.rs:14:27
+  --> $DIR/gat-trait-path-parenthesised-args.rs:12:27
    |
 LL | fn bar<'a>(arg: Box<dyn X<Y() = ()>>) {}
    |                           ^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/gat-trait-path-parenthesised-args.rs:4:8
+  --> $DIR/gat-trait-path-parenthesised-args.rs:2:8
    |
 LL |   type Y<'a>;
    |        ^ --
diff --git a/src/test/ui/generic-associated-types/generic-associated-type-bounds.rs b/src/test/ui/generic-associated-types/generic-associated-type-bounds.rs
index d7c4dbda2644..fdc5a72671ca 100644
--- a/src/test/ui/generic-associated-types/generic-associated-type-bounds.rs
+++ b/src/test/ui/generic-associated-types/generic-associated-type-bounds.rs
@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(generic_associated_types)]
-
 pub trait X {
     type Y<'a> where Self: 'a;
     fn m(&self) -> Self::Y<'_>;
diff --git a/src/test/ui/generic-associated-types/generic-associated-types-where.rs b/src/test/ui/generic-associated-types/generic-associated-types-where.rs
index 2ecbc8c59125..bbdfffafedb7 100644
--- a/src/test/ui/generic-associated-types/generic-associated-types-where.rs
+++ b/src/test/ui/generic-associated-types/generic-associated-types-where.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // Checking the interaction with this other feature
 #![feature(associated_type_defaults)]
 
diff --git a/src/test/ui/generic-associated-types/generic-associated-types-where.stderr b/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
index e866b3bab797..9a745c099c0e 100644
--- a/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
+++ b/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `T` doesn't implement `std::fmt::Display`
-  --> $DIR/generic-associated-types-where.rs:20:22
+  --> $DIR/generic-associated-types-where.rs:18:22
    |
 LL |     type Assoc2<T> = Vec<T>;
    |                      ^^^^^^ `T` cannot be formatted with the default formatter
@@ -11,7 +11,7 @@ LL |     type Assoc2<T: std::fmt::Display> = Vec<T>;
    |                  +++++++++++++++++++
 
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/generic-associated-types-where.rs:22:38
+  --> $DIR/generic-associated-types-where.rs:20:38
    |
 LL |     type Assoc3<T>;
    |     -------------- definition of `Assoc3` from trait
diff --git a/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.rs b/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.rs
index 43058f7eb41b..2cb218bf8f25 100644
--- a/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.rs
+++ b/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 use std::ops::Deref;
 
 trait Iterable {
diff --git a/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.stderr b/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.stderr
index a4bb361900fe..396ff15ab1a4 100644
--- a/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.stderr
+++ b/src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.stderr
@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'b`
-  --> $DIR/generic_associated_type_undeclared_lifetimes.rs:8:37
+  --> $DIR/generic_associated_type_undeclared_lifetimes.rs:6:37
    |
 LL |         + Deref<Target = Self::Item<'b>>;
    |                                     ^^ undeclared lifetime
@@ -19,7 +19,7 @@ LL | trait Iterable<'b> {
    |               ++++
 
 error[E0261]: use of undeclared lifetime name `'undeclared`
-  --> $DIR/generic_associated_type_undeclared_lifetimes.rs:11:41
+  --> $DIR/generic_associated_type_undeclared_lifetimes.rs:9:41
    |
 LL |     fn iter<'a>(&'a self) -> Self::Iter<'undeclared>;
    |                                         ^^^^^^^^^^^ undeclared lifetime
diff --git a/src/test/ui/generic-associated-types/impl_bounds.rs b/src/test/ui/generic-associated-types/impl_bounds.rs
index ec1d171c0447..01165fcebaf7 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.rs
+++ b/src/test/ui/generic-associated-types/impl_bounds.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 trait Foo {
diff --git a/src/test/ui/generic-associated-types/impl_bounds.stderr b/src/test/ui/generic-associated-types/impl_bounds.stderr
index 4f8d673d1cf2..442d4f33690e 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.stderr
+++ b/src/test/ui/generic-associated-types/impl_bounds.stderr
@@ -1,5 +1,5 @@
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/impl_bounds.rs:15:39
+  --> $DIR/impl_bounds.rs:14:39
    |
 LL |     type A<'a> where Self: 'a;
    |     ---------- definition of `A` from trait
@@ -8,7 +8,7 @@ LL |     type A<'a> = (&'a ()) where Self: 'static;
    |                                       ^^^^^^^ impl has extra requirement `T: 'static`
 
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/impl_bounds.rs:17:48
+  --> $DIR/impl_bounds.rs:16:48
    |
 LL |     type B<'a, 'b> where 'a: 'b;
    |     -------------- definition of `B` from trait
@@ -17,7 +17,7 @@ LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |                                                ^^ impl has extra requirement `'b: 'a`
 
 error[E0478]: lifetime bound not satisfied
-  --> $DIR/impl_bounds.rs:17:22
+  --> $DIR/impl_bounds.rs:16:22
    |
 LL |     type B<'a, 'b> where 'a: 'b;
    |     -------------- definition of `B` from trait
@@ -26,29 +26,29 @@ LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |                      ^^^^^^^^^^^^^^^             - help: try copying this clause from the trait: `, 'a: 'b`
    |
 note: lifetime parameter instantiated with the lifetime `'a` as defined here
-  --> $DIR/impl_bounds.rs:17:12
+  --> $DIR/impl_bounds.rs:16:12
    |
 LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |            ^^
 note: but lifetime parameter must outlive the lifetime `'b` as defined here
-  --> $DIR/impl_bounds.rs:17:16
+  --> $DIR/impl_bounds.rs:16:16
    |
 LL |     type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
    |                ^^
 
 error[E0277]: the trait bound `T: Copy` is not satisfied
-  --> $DIR/impl_bounds.rs:20:33
+  --> $DIR/impl_bounds.rs:19:33
    |
 LL |     type C = String where Self: Copy;
    |                                 ^^^^ the trait `Copy` is not implemented for `T`
    |
 note: required for `Fooy<T>` to implement `Copy`
-  --> $DIR/impl_bounds.rs:11:10
+  --> $DIR/impl_bounds.rs:10:10
    |
 LL | #[derive(Copy, Clone)]
    |          ^^^^
 note: the requirement `Fooy<T>: Copy` appears on the `impl`'s associated type `C` but not on the corresponding trait's associated type
-  --> $DIR/impl_bounds.rs:7:10
+  --> $DIR/impl_bounds.rs:6:10
    |
 LL | trait Foo {
    |       --- in this trait
@@ -62,18 +62,18 @@ LL | impl<T: std::marker::Copy> Foo for Fooy<T> {
    |       +++++++++++++++++++
 
 error[E0277]: the trait bound `T: Copy` is not satisfied
-  --> $DIR/impl_bounds.rs:22:24
+  --> $DIR/impl_bounds.rs:21:24
    |
 LL |     fn d() where Self: Copy {}
    |                        ^^^^ the trait `Copy` is not implemented for `T`
    |
 note: required for `Fooy<T>` to implement `Copy`
-  --> $DIR/impl_bounds.rs:11:10
+  --> $DIR/impl_bounds.rs:10:10
    |
 LL | #[derive(Copy, Clone)]
    |          ^^^^
 note: the requirement `Fooy<T>: Copy` appears on the `impl`'s method `d` but not on the corresponding trait's method
-  --> $DIR/impl_bounds.rs:8:8
+  --> $DIR/impl_bounds.rs:7:8
    |
 LL | trait Foo {
    |       --- in this trait
diff --git a/src/test/ui/generic-associated-types/impl_bounds_ok.rs b/src/test/ui/generic-associated-types/impl_bounds_ok.rs
index 4df8235d95f3..88f829ea25a5 100644
--- a/src/test/ui/generic-associated-types/impl_bounds_ok.rs
+++ b/src/test/ui/generic-associated-types/impl_bounds_ok.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 trait Foo {
diff --git a/src/test/ui/generic-associated-types/issue-101020.rs b/src/test/ui/generic-associated-types/issue-101020.rs
index 51cabe21e629..80d0fa5ad34b 100644
--- a/src/test/ui/generic-associated-types/issue-101020.rs
+++ b/src/test/ui/generic-associated-types/issue-101020.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 pub trait LendingIterator {
     type Item<'a>
     where
diff --git a/src/test/ui/generic-associated-types/issue-101020.stderr b/src/test/ui/generic-associated-types/issue-101020.stderr
index 7fde89eb75e5..b4e94cb83f73 100644
--- a/src/test/ui/generic-associated-types/issue-101020.stderr
+++ b/src/test/ui/generic-associated-types/issue-101020.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `for<'a> &'a mut (): Foo<&'a mut ()>` is not satisfied
-  --> $DIR/issue-101020.rs:33:5
+  --> $DIR/issue-101020.rs:31:5
    |
 LL |     (&mut EmptyIter).consume(());
    |     ^^^^^^^^^^^^^^^^ ------- required by a bound introduced by this call
@@ -7,12 +7,12 @@ LL |     (&mut EmptyIter).consume(());
    |     the trait `for<'a> Foo<&'a mut ()>` is not implemented for `&'a mut ()`
    |
 note: required for `&'a mut ()` to implement `for<'a> FuncInput<'a, &'a mut ()>`
-  --> $DIR/issue-101020.rs:29:20
+  --> $DIR/issue-101020.rs:27:20
    |
 LL | impl<'a, T, F: 'a> FuncInput<'a, F> for T where F: Foo<T> {}
    |                    ^^^^^^^^^^^^^^^^     ^
 note: required by a bound in `LendingIterator::consume`
-  --> $DIR/issue-101020.rs:11:33
+  --> $DIR/issue-101020.rs:9:33
    |
 LL |     fn consume<F>(self, _f: F)
    |        ------- required by a bound in this
diff --git a/src/test/ui/generic-associated-types/issue-47206-where-clause.rs b/src/test/ui/generic-associated-types/issue-47206-where-clause.rs
index d352c1948f23..3d1b88ddf299 100644
--- a/src/test/ui/generic-associated-types/issue-47206-where-clause.rs
+++ b/src/test/ui/generic-associated-types/issue-47206-where-clause.rs
@@ -1,7 +1,5 @@
 // Check that this program doesn't cause the compiler to error without output.
 
-#![feature(generic_associated_types)]
-
 trait Foo {
     type Assoc3<T>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr b/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr
index 31948a878edf..7006744df498 100644
--- a/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr
+++ b/src/test/ui/generic-associated-types/issue-47206-where-clause.stderr
@@ -1,5 +1,5 @@
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/issue-47206-where-clause.rs:12:38
+  --> $DIR/issue-47206-where-clause.rs:10:38
    |
 LL |     type Assoc3<T>;
    |     -------------- definition of `Assoc3` from trait
diff --git a/src/test/ui/generic-associated-types/issue-58694-parameter-out-of-range.rs b/src/test/ui/generic-associated-types/issue-58694-parameter-out-of-range.rs
index e87a76825c37..625ccfe89e09 100644
--- a/src/test/ui/generic-associated-types/issue-58694-parameter-out-of-range.rs
+++ b/src/test/ui/generic-associated-types/issue-58694-parameter-out-of-range.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Cert {
     type PublicKey<'a>: From<&'a [u8]>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.rs b/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.rs
index d74d6d056d66..c1140bff82ba 100644
--- a/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.rs
+++ b/src/test/ui/generic-associated-types/issue-62326-parameter-out-of-range.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // check-pass
 
 trait Iterator {
diff --git a/src/test/ui/generic-associated-types/issue-67424.rs b/src/test/ui/generic-associated-types/issue-67424.rs
index fa35a3e8b04d..b6c7c70cd831 100644
--- a/src/test/ui/generic-associated-types/issue-67424.rs
+++ b/src/test/ui/generic-associated-types/issue-67424.rs
@@ -1,3 +1,4 @@
+// check-pass
 // Fixed by #67160
 
 trait Trait1 {
@@ -6,7 +7,6 @@ trait Trait1 {
 
 trait Trait2 {
     type Type1<B>: Trait1<A=B>;
-    //~^ ERROR: generic associated types are unstable
 }
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-67424.stderr b/src/test/ui/generic-associated-types/issue-67424.stderr
deleted file mode 100644
index bbb7d56f5928..000000000000
--- a/src/test/ui/generic-associated-types/issue-67424.stderr
+++ /dev/null
@@ -1,12 +0,0 @@
-error[E0658]: generic associated types are unstable
-  --> $DIR/issue-67424.rs:8:5
-   |
-LL |     type Type1<B>: Trait1<A=B>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
-   = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/generic-associated-types/issue-67510-pass.base.stderr b/src/test/ui/generic-associated-types/issue-67510-pass.base.stderr
index 74a616aaabe3..4cc68530ee1a 100644
--- a/src/test/ui/generic-associated-types/issue-67510-pass.base.stderr
+++ b/src/test/ui/generic-associated-types/issue-67510-pass.base.stderr
@@ -1,11 +1,11 @@
 error[E0038]: the trait `X` cannot be made into an object
-  --> $DIR/issue-67510-pass.rs:13:23
+  --> $DIR/issue-67510-pass.rs:12:23
    |
 LL | fn _func1<'a>(_x: Box<dyn X<Y<'a>=&'a ()>>) {}
    |                       ^^^^^^^^^^^^^^^^^^^ `X` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-67510-pass.rs:10:10
+  --> $DIR/issue-67510-pass.rs:9:10
    |
 LL | trait X {
    |       - this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/issue-67510-pass.rs b/src/test/ui/generic-associated-types/issue-67510-pass.rs
index c5b02ff9a640..66ce3e807a15 100644
--- a/src/test/ui/generic-associated-types/issue-67510-pass.rs
+++ b/src/test/ui/generic-associated-types/issue-67510-pass.rs
@@ -2,7 +2,6 @@
 //[base] check-fail
 //[extended] check-pass
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/issue-67510.rs b/src/test/ui/generic-associated-types/issue-67510.rs
index 5725b660ab23..ab5c25d74da7 100644
--- a/src/test/ui/generic-associated-types/issue-67510.rs
+++ b/src/test/ui/generic-associated-types/issue-67510.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-67510.stderr b/src/test/ui/generic-associated-types/issue-67510.stderr
index 8aeda22bad75..d25c5b0f387c 100644
--- a/src/test/ui/generic-associated-types/issue-67510.stderr
+++ b/src/test/ui/generic-associated-types/issue-67510.stderr
@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/issue-67510.rs:7:21
+  --> $DIR/issue-67510.rs:5:21
    |
 LL | fn f(x: Box<dyn X<Y<'a> = &'a ()>>) {}
    |                     ^^ undeclared lifetime
@@ -15,7 +15,7 @@ LL | fn f<'a>(x: Box<dyn X<Y<'a> = &'a ()>>) {}
    |     ++++
 
 error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/issue-67510.rs:7:28
+  --> $DIR/issue-67510.rs:5:28
    |
 LL | fn f(x: Box<dyn X<Y<'a> = &'a ()>>) {}
    |                            ^^ undeclared lifetime
@@ -30,13 +30,13 @@ LL | fn f<'a>(x: Box<dyn X<Y<'a> = &'a ()>>) {}
    |     ++++
 
 error[E0038]: the trait `X` cannot be made into an object
-  --> $DIR/issue-67510.rs:7:13
+  --> $DIR/issue-67510.rs:5:13
    |
 LL | fn f(x: Box<dyn X<Y<'a> = &'a ()>>) {}
    |             ^^^^^^^^^^^^^^^^^^^^^ `X` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-67510.rs:4:10
+  --> $DIR/issue-67510.rs:2:10
    |
 LL | trait X {
    |       - this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.rs b/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.rs
index 617d985dce9f..f1e779fcb006 100644
--- a/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.rs
+++ b/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.rs
@@ -1,7 +1,5 @@
 // Regression test for #68641
 
-#![feature(generic_associated_types)]
-
 trait UnsafeCopy {
     type Item<'a>: Copy;
 
diff --git a/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.stderr b/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.stderr
index 2e21b38cb0e9..6bb7492af811 100644
--- a/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.stderr
+++ b/src/test/ui/generic-associated-types/issue-68641-check-gat-bounds.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `T: Copy` is not satisfied
-  --> $DIR/issue-68641-check-gat-bounds.rs:14:21
+  --> $DIR/issue-68641-check-gat-bounds.rs:12:21
    |
 LL |     type Item<'a> = T;
    |                     ^ the trait `Copy` is not implemented for `T`
    |
 note: required by a bound in `UnsafeCopy::Item`
-  --> $DIR/issue-68641-check-gat-bounds.rs:6:20
+  --> $DIR/issue-68641-check-gat-bounds.rs:4:20
    |
 LL |     type Item<'a>: Copy;
    |                    ^^^^ required by this bound in `UnsafeCopy::Item`
diff --git a/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.rs b/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.rs
index def0ad18f232..f5502adee426 100644
--- a/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.rs
+++ b/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.rs
@@ -1,7 +1,5 @@
 // Regression test for #68642
 
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>: Fn() -> u32;
 
diff --git a/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.stderr b/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.stderr
index 713cc744f5a2..07452137b5bd 100644
--- a/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.stderr
+++ b/src/test/ui/generic-associated-types/issue-68642-broken-llvm-ir.stderr
@@ -1,12 +1,12 @@
 error[E0277]: expected a `Fn<()>` closure, found `T`
-  --> $DIR/issue-68642-broken-llvm-ir.rs:14:18
+  --> $DIR/issue-68642-broken-llvm-ir.rs:12:18
    |
 LL |     type F<'a> = Self;
    |                  ^^^^ expected an `Fn<()>` closure, found `T`
    |
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }`
 note: required by a bound in `Fun::F`
-  --> $DIR/issue-68642-broken-llvm-ir.rs:6:17
+  --> $DIR/issue-68642-broken-llvm-ir.rs:4:17
    |
 LL |     type F<'a>: Fn() -> u32;
    |                 ^^^^^^^^^^^ required by this bound in `Fun::F`
diff --git a/src/test/ui/generic-associated-types/issue-68643-broken-mir.rs b/src/test/ui/generic-associated-types/issue-68643-broken-mir.rs
index 9af065b5d26d..6050a8bf5618 100644
--- a/src/test/ui/generic-associated-types/issue-68643-broken-mir.rs
+++ b/src/test/ui/generic-associated-types/issue-68643-broken-mir.rs
@@ -1,7 +1,5 @@
 // Regression test for #68643
 
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>: Fn() -> u32;
 
diff --git a/src/test/ui/generic-associated-types/issue-68643-broken-mir.stderr b/src/test/ui/generic-associated-types/issue-68643-broken-mir.stderr
index a7b7f64cdb17..31ded5dab95b 100644
--- a/src/test/ui/generic-associated-types/issue-68643-broken-mir.stderr
+++ b/src/test/ui/generic-associated-types/issue-68643-broken-mir.stderr
@@ -1,12 +1,12 @@
 error[E0277]: expected a `Fn<()>` closure, found `T`
-  --> $DIR/issue-68643-broken-mir.rs:14:18
+  --> $DIR/issue-68643-broken-mir.rs:12:18
    |
 LL |     type F<'a> = Self;
    |                  ^^^^ expected an `Fn<()>` closure, found `T`
    |
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }`
 note: required by a bound in `Fun::F`
-  --> $DIR/issue-68643-broken-mir.rs:6:17
+  --> $DIR/issue-68643-broken-mir.rs:4:17
    |
 LL |     type F<'a>: Fn() -> u32;
    |                 ^^^^^^^^^^^ required by this bound in `Fun::F`
diff --git a/src/test/ui/generic-associated-types/issue-68644-codegen-selection.rs b/src/test/ui/generic-associated-types/issue-68644-codegen-selection.rs
index 1d2636c260d8..898cfa1e744c 100644
--- a/src/test/ui/generic-associated-types/issue-68644-codegen-selection.rs
+++ b/src/test/ui/generic-associated-types/issue-68644-codegen-selection.rs
@@ -1,7 +1,5 @@
 // Regression test for #68644
 
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>: Fn() -> u32;
 
diff --git a/src/test/ui/generic-associated-types/issue-68644-codegen-selection.stderr b/src/test/ui/generic-associated-types/issue-68644-codegen-selection.stderr
index 5e921e053bb4..e2f9930cc67f 100644
--- a/src/test/ui/generic-associated-types/issue-68644-codegen-selection.stderr
+++ b/src/test/ui/generic-associated-types/issue-68644-codegen-selection.stderr
@@ -1,12 +1,12 @@
 error[E0277]: expected a `Fn<()>` closure, found `T`
-  --> $DIR/issue-68644-codegen-selection.rs:14:18
+  --> $DIR/issue-68644-codegen-selection.rs:12:18
    |
 LL |     type F<'a> = Self;
    |                  ^^^^ expected an `Fn<()>` closure, found `T`
    |
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }`
 note: required by a bound in `Fun::F`
-  --> $DIR/issue-68644-codegen-selection.rs:6:17
+  --> $DIR/issue-68644-codegen-selection.rs:4:17
    |
 LL |     type F<'a>: Fn() -> u32;
    |                 ^^^^^^^^^^^ required by this bound in `Fun::F`
diff --git a/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.rs b/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.rs
index aa505064f8c5..60b065bfc317 100644
--- a/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.rs
+++ b/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.rs
@@ -1,7 +1,5 @@
 // Regression test for #68645
 
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>: Fn() -> u32;
 
diff --git a/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.stderr b/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.stderr
index 7edcdce628e6..0065368ad31d 100644
--- a/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.stderr
+++ b/src/test/ui/generic-associated-types/issue-68645-codegen-fulfillment.stderr
@@ -1,12 +1,12 @@
 error[E0277]: expected a `Fn<()>` closure, found `T`
-  --> $DIR/issue-68645-codegen-fulfillment.rs:14:18
+  --> $DIR/issue-68645-codegen-fulfillment.rs:12:18
    |
 LL |     type F<'a> = Self;
    |                  ^^^^ expected an `Fn<()>` closure, found `T`
    |
    = note: wrap the `T` in a closure with no arguments: `|| { /* code */ }`
 note: required by a bound in `Fun::F`
-  --> $DIR/issue-68645-codegen-fulfillment.rs:6:17
+  --> $DIR/issue-68645-codegen-fulfillment.rs:4:17
    |
 LL |     type F<'a>: Fn() -> u32;
    |                 ^^^^^^^^^^^ required by this bound in `Fun::F`
diff --git a/src/test/ui/generic-associated-types/issue-68648-1.rs b/src/test/ui/generic-associated-types/issue-68648-1.rs
index 17bc034b3958..0df41bab3272 100644
--- a/src/test/ui/generic-associated-types/issue-68648-1.rs
+++ b/src/test/ui/generic-associated-types/issue-68648-1.rs
@@ -1,8 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
-
 trait Fun {
     type F<'a>;
 
diff --git a/src/test/ui/generic-associated-types/issue-68648-2.rs b/src/test/ui/generic-associated-types/issue-68648-2.rs
index 6c9a0d126a78..0f963d58f5e8 100644
--- a/src/test/ui/generic-associated-types/issue-68648-2.rs
+++ b/src/test/ui/generic-associated-types/issue-68648-2.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>;
 
diff --git a/src/test/ui/generic-associated-types/issue-68648-2.stderr b/src/test/ui/generic-associated-types/issue-68648-2.stderr
index 06c1efcd80b0..b2bef19eb5e9 100644
--- a/src/test/ui/generic-associated-types/issue-68648-2.stderr
+++ b/src/test/ui/generic-associated-types/issue-68648-2.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-68648-2.rs:14:17
+  --> $DIR/issue-68648-2.rs:12:17
    |
 LL | fn bug<'a, T: Fun<F<'a> = T>>(t: T) -> T::F<'a> {
    |            - this type parameter
@@ -11,7 +11,7 @@ LL |     T::identity(())
    = note: expected type parameter `T`
                    found unit type `()`
 note: associated function defined here
-  --> $DIR/issue-68648-2.rs:6:8
+  --> $DIR/issue-68648-2.rs:4:8
    |
 LL |     fn identity<'a>(t: Self::F<'a>) -> Self::F<'a> { t }
    |        ^^^^^^^^     --------------
diff --git a/src/test/ui/generic-associated-types/issue-68649-pass.rs b/src/test/ui/generic-associated-types/issue-68649-pass.rs
index 33f08faff56b..772743877954 100644
--- a/src/test/ui/generic-associated-types/issue-68649-pass.rs
+++ b/src/test/ui/generic-associated-types/issue-68649-pass.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>;
 
diff --git a/src/test/ui/generic-associated-types/issue-68653.rs b/src/test/ui/generic-associated-types/issue-68653.rs
index 1e84717e9259..170b87cf2528 100644
--- a/src/test/ui/generic-associated-types/issue-68653.rs
+++ b/src/test/ui/generic-associated-types/issue-68653.rs
@@ -2,8 +2,6 @@
 
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a: 'a>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-68656-unsized-values.rs b/src/test/ui/generic-associated-types/issue-68656-unsized-values.rs
index c0d933362567..607cfed0bc64 100644
--- a/src/test/ui/generic-associated-types/issue-68656-unsized-values.rs
+++ b/src/test/ui/generic-associated-types/issue-68656-unsized-values.rs
@@ -1,7 +1,5 @@
 // Regression test for #68656
 
-#![feature(generic_associated_types)]
-
 trait UnsafeCopy<T: Copy> {
     type Item<'a>: std::ops::Deref<Target = T>;
 
diff --git a/src/test/ui/generic-associated-types/issue-68656-unsized-values.stderr b/src/test/ui/generic-associated-types/issue-68656-unsized-values.stderr
index 8e0f23716019..e8770aedfa1c 100644
--- a/src/test/ui/generic-associated-types/issue-68656-unsized-values.stderr
+++ b/src/test/ui/generic-associated-types/issue-68656-unsized-values.stderr
@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<T as Deref>::Target == T`
-  --> $DIR/issue-68656-unsized-values.rs:15:21
+  --> $DIR/issue-68656-unsized-values.rs:13:21
    |
 LL | impl<T: Copy + std::ops::Deref> UnsafeCopy<T> for T {
    |      - this type parameter
@@ -9,7 +9,7 @@ LL |     type Item<'a> = T;
    = note: expected type parameter `T`
              found associated type `<T as Deref>::Target`
 note: required by a bound in `UnsafeCopy::Item`
-  --> $DIR/issue-68656-unsized-values.rs:6:36
+  --> $DIR/issue-68656-unsized-values.rs:4:36
    |
 LL |     type Item<'a>: std::ops::Deref<Target = T>;
    |                                    ^^^^^^^^^^ required by this bound in `UnsafeCopy::Item`
diff --git a/src/test/ui/generic-associated-types/issue-70303.rs b/src/test/ui/generic-associated-types/issue-70303.rs
index 568996e1a17a..0edff5e4e339 100644
--- a/src/test/ui/generic-associated-types/issue-70303.rs
+++ b/src/test/ui/generic-associated-types/issue-70303.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Document {
     type Cursor<'a>: DocCursor<'a> where Self: 'a;
 
diff --git a/src/test/ui/generic-associated-types/issue-70304.rs b/src/test/ui/generic-associated-types/issue-70304.rs
index f778f985cf0d..8898d4c7d135 100644
--- a/src/test/ui/generic-associated-types/issue-70304.rs
+++ b/src/test/ui/generic-associated-types/issue-70304.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Document {
     type Cursor<'a>: DocCursor<'a>;
     //~^ ERROR: missing required bound on `Cursor`
diff --git a/src/test/ui/generic-associated-types/issue-70304.stderr b/src/test/ui/generic-associated-types/issue-70304.stderr
index bba7cab7093c..99339e968595 100644
--- a/src/test/ui/generic-associated-types/issue-70304.stderr
+++ b/src/test/ui/generic-associated-types/issue-70304.stderr
@@ -1,11 +1,11 @@
 error[E0637]: `'_` cannot be used here
-  --> $DIR/issue-70304.rs:48:41
+  --> $DIR/issue-70304.rs:46:41
    |
 LL | fn create_doc() -> impl Document<Cursor<'_> = DocCursorImpl<'_>> {
    |                                         ^^ `'_` is a reserved lifetime name
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/issue-70304.rs:48:61
+  --> $DIR/issue-70304.rs:46:61
    |
 LL | fn create_doc() -> impl Document<Cursor<'_> = DocCursorImpl<'_>> {
    |                                                             ^^ expected named lifetime parameter
@@ -17,7 +17,7 @@ LL | fn create_doc() -> impl Document<Cursor<'_> = DocCursorImpl<'static>> {
    |                                                             ~~~~~~~
 
 error: missing required bound on `Cursor`
-  --> $DIR/issue-70304.rs:4:5
+  --> $DIR/issue-70304.rs:2:5
    |
 LL |     type Cursor<'a>: DocCursor<'a>;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
diff --git a/src/test/ui/generic-associated-types/issue-71176.rs b/src/test/ui/generic-associated-types/issue-71176.rs
index c2f0d59f4435..f0e162d825f9 100644
--- a/src/test/ui/generic-associated-types/issue-71176.rs
+++ b/src/test/ui/generic-associated-types/issue-71176.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Provider {
     type A<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-71176.stderr b/src/test/ui/generic-associated-types/issue-71176.stderr
index 08c8d41624e2..386c97161c8f 100644
--- a/src/test/ui/generic-associated-types/issue-71176.stderr
+++ b/src/test/ui/generic-associated-types/issue-71176.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `Provider::A`
-  --> $DIR/issue-71176.rs:12:27
+  --> $DIR/issue-71176.rs:10:27
    |
 LL |   inner: Box<dyn Provider<A = B>>,
    |                           ^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-71176.rs:4:10
+  --> $DIR/issue-71176.rs:2:10
    |
 LL |     type A<'a>;
    |          ^ --
diff --git a/src/test/ui/generic-associated-types/issue-74684-1.rs b/src/test/ui/generic-associated-types/issue-74684-1.rs
index 0e3899a88cc9..e9ec80074f89 100644
--- a/src/test/ui/generic-associated-types/issue-74684-1.rs
+++ b/src/test/ui/generic-associated-types/issue-74684-1.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>: ?Sized;
 
diff --git a/src/test/ui/generic-associated-types/issue-74684-1.stderr b/src/test/ui/generic-associated-types/issue-74684-1.stderr
index 2cd050ed8be6..cacc973077ce 100644
--- a/src/test/ui/generic-associated-types/issue-74684-1.stderr
+++ b/src/test/ui/generic-associated-types/issue-74684-1.stderr
@@ -1,5 +1,5 @@
 error[E0597]: `a` does not live long enough
-  --> $DIR/issue-74684-1.rs:15:26
+  --> $DIR/issue-74684-1.rs:13:26
    |
 LL | fn bug<'a, T: ?Sized + Fun<F<'a> = [u8]>>(_ : Box<T>) -> &'static T::F<'a> {
    |        -- lifetime `'a` defined here
diff --git a/src/test/ui/generic-associated-types/issue-74684-2.rs b/src/test/ui/generic-associated-types/issue-74684-2.rs
index fca55070b5ba..ff243af2cb39 100644
--- a/src/test/ui/generic-associated-types/issue-74684-2.rs
+++ b/src/test/ui/generic-associated-types/issue-74684-2.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Fun {
     type F<'a>: ?Sized;
 
diff --git a/src/test/ui/generic-associated-types/issue-74684-2.stderr b/src/test/ui/generic-associated-types/issue-74684-2.stderr
index 7c2935d32bfd..59b85abf5c8c 100644
--- a/src/test/ui/generic-associated-types/issue-74684-2.stderr
+++ b/src/test/ui/generic-associated-types/issue-74684-2.stderr
@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<{integer} as Fun>::F<'_> == [u8]`
-  --> $DIR/issue-74684-2.rs:23:9
+  --> $DIR/issue-74684-2.rs:21:9
    |
 LL |     bug(Box::new(x));
    |     --- ^^^^^^^^^^^ type mismatch resolving `<{integer} as Fun>::F<'_> == [u8]`
@@ -7,12 +7,12 @@ LL |     bug(Box::new(x));
    |     required by a bound introduced by this call
    |
 note: expected this to be `[u8]`
-  --> $DIR/issue-74684-2.rs:10:18
+  --> $DIR/issue-74684-2.rs:8:18
    |
 LL |     type F<'a> = i32;
    |                  ^^^
 note: required by a bound in `bug`
-  --> $DIR/issue-74684-2.rs:13:28
+  --> $DIR/issue-74684-2.rs:11:28
    |
 LL | fn bug<'a, T: ?Sized + Fun<F<'a> = [u8]>>(t: Box<T>) -> &'static T::F<'a> {
    |                            ^^^^^^^^^^^^ required by this bound in `bug`
diff --git a/src/test/ui/generic-associated-types/issue-74816.rs b/src/test/ui/generic-associated-types/issue-74816.rs
index c932025d1178..344afb87f99c 100644
--- a/src/test/ui/generic-associated-types/issue-74816.rs
+++ b/src/test/ui/generic-associated-types/issue-74816.rs
@@ -1,5 +1,4 @@
 #![feature(associated_type_defaults)]
-#![feature(generic_associated_types)]
 
 trait Trait1 {
     fn foo();
diff --git a/src/test/ui/generic-associated-types/issue-74816.stderr b/src/test/ui/generic-associated-types/issue-74816.stderr
index 9eaa74e343e4..45018e6976cf 100644
--- a/src/test/ui/generic-associated-types/issue-74816.stderr
+++ b/src/test/ui/generic-associated-types/issue-74816.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `Self: Trait1` is not satisfied
-  --> $DIR/issue-74816.rs:9:31
+  --> $DIR/issue-74816.rs:8:31
    |
 LL |     type Associated: Trait1 = Self;
    |                               ^^^^ the trait `Trait1` is not implemented for `Self`
    |
 note: required by a bound in `Trait2::Associated`
-  --> $DIR/issue-74816.rs:9:22
+  --> $DIR/issue-74816.rs:8:22
    |
 LL |     type Associated: Trait1 = Self;
    |                      ^^^^^^ required by this bound in `Trait2::Associated`
@@ -15,13 +15,13 @@ LL | trait Trait2: Trait1 {
    |             ++++++++
 
 error[E0277]: the size for values of type `Self` cannot be known at compilation time
-  --> $DIR/issue-74816.rs:9:31
+  --> $DIR/issue-74816.rs:8:31
    |
 LL |     type Associated: Trait1 = Self;
    |                               ^^^^ doesn't have a size known at compile-time
    |
 note: required by a bound in `Trait2::Associated`
-  --> $DIR/issue-74816.rs:9:5
+  --> $DIR/issue-74816.rs:8:5
    |
 LL |     type Associated: Trait1 = Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Trait2::Associated`
diff --git a/src/test/ui/generic-associated-types/issue-74824.rs b/src/test/ui/generic-associated-types/issue-74824.rs
index 1bbf7aac5cda..10c45d133642 100644
--- a/src/test/ui/generic-associated-types/issue-74824.rs
+++ b/src/test/ui/generic-associated-types/issue-74824.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 use std::ops::Deref;
diff --git a/src/test/ui/generic-associated-types/issue-74824.stderr b/src/test/ui/generic-associated-types/issue-74824.stderr
index eabc806c2b7d..623adb1c2ad1 100644
--- a/src/test/ui/generic-associated-types/issue-74824.stderr
+++ b/src/test/ui/generic-associated-types/issue-74824.stderr
@@ -1,24 +1,24 @@
 error[E0277]: the trait bound `Box<T>: Copy` is not satisfied
-  --> $DIR/issue-74824.rs:7:26
+  --> $DIR/issue-74824.rs:6:26
    |
 LL |     type Copy<T>: Copy = Box<T>;
    |                          ^^^^^^ the trait `Copy` is not implemented for `Box<T>`
    |
 note: required by a bound in `UnsafeCopy::Copy`
-  --> $DIR/issue-74824.rs:7:19
+  --> $DIR/issue-74824.rs:6:19
    |
 LL |     type Copy<T>: Copy = Box<T>;
    |                   ^^^^ required by this bound in `UnsafeCopy::Copy`
 
 error[E0277]: the trait bound `T: Clone` is not satisfied
-  --> $DIR/issue-74824.rs:7:26
+  --> $DIR/issue-74824.rs:6:26
    |
 LL |     type Copy<T>: Copy = Box<T>;
    |                          ^^^^^^ the trait `Clone` is not implemented for `T`
    |
    = note: required for `Box<T>` to implement `Clone`
 note: required by a bound in `UnsafeCopy::Copy`
-  --> $DIR/issue-74824.rs:7:19
+  --> $DIR/issue-74824.rs:6:19
    |
 LL |     type Copy<T>: Copy = Box<T>;
    |                   ^^^^ required by this bound in `UnsafeCopy::Copy`
diff --git a/src/test/ui/generic-associated-types/issue-76407.rs b/src/test/ui/generic-associated-types/issue-76407.rs
index a8141829ba88..9556ec6da253 100644
--- a/src/test/ui/generic-associated-types/issue-76407.rs
+++ b/src/test/ui/generic-associated-types/issue-76407.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Marker {}
 
 impl Marker for u32 {}
diff --git a/src/test/ui/generic-associated-types/issue-76535.base.stderr b/src/test/ui/generic-associated-types/issue-76535.base.stderr
index fe5fe964e991..088f69b09f70 100644
--- a/src/test/ui/generic-associated-types/issue-76535.base.stderr
+++ b/src/test/ui/generic-associated-types/issue-76535.base.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `SuperTrait::SubType`
-  --> $DIR/issue-76535.rs:40:33
+  --> $DIR/issue-76535.rs:39:33
    |
 LL |     let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
    |                                 ^^^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-76535.rs:10:10
+  --> $DIR/issue-76535.rs:9:10
    |
 LL |     type SubType<'a>: SubTrait where Self: 'a;
    |          ^^^^^^^ --
@@ -15,13 +15,13 @@ LL |     let sub: Box<dyn SuperTrait<SubType<'a> = SubStruct>> = Box::new(SuperS
    |                                 ~~~~~~~~~~~
 
 error[E0038]: the trait `SuperTrait` cannot be made into an object
-  --> $DIR/issue-76535.rs:40:14
+  --> $DIR/issue-76535.rs:39:14
    |
 LL |     let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SuperTrait` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-76535.rs:10:10
+  --> $DIR/issue-76535.rs:9:10
    |
 LL | pub trait SuperTrait {
    |           ---------- this trait cannot be made into an object...
@@ -30,13 +30,13 @@ LL |     type SubType<'a>: SubTrait where Self: 'a;
    = help: consider moving `SubType` to another trait
 
 error[E0038]: the trait `SuperTrait` cannot be made into an object
-  --> $DIR/issue-76535.rs:40:57
+  --> $DIR/issue-76535.rs:39:57
    |
 LL |     let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
    |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SuperTrait` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-76535.rs:10:10
+  --> $DIR/issue-76535.rs:9:10
    |
 LL | pub trait SuperTrait {
    |           ---------- this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/issue-76535.extended.stderr b/src/test/ui/generic-associated-types/issue-76535.extended.stderr
index 067d0489b486..e79f0a73f5b5 100644
--- a/src/test/ui/generic-associated-types/issue-76535.extended.stderr
+++ b/src/test/ui/generic-associated-types/issue-76535.extended.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `SuperTrait::SubType`
-  --> $DIR/issue-76535.rs:40:33
+  --> $DIR/issue-76535.rs:39:33
    |
 LL |     let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
    |                                 ^^^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-76535.rs:10:10
+  --> $DIR/issue-76535.rs:9:10
    |
 LL |     type SubType<'a>: SubTrait where Self: 'a;
    |          ^^^^^^^ --
diff --git a/src/test/ui/generic-associated-types/issue-76535.rs b/src/test/ui/generic-associated-types/issue-76535.rs
index 46f217ba06bc..2457a05a0672 100644
--- a/src/test/ui/generic-associated-types/issue-76535.rs
+++ b/src/test/ui/generic-associated-types/issue-76535.rs
@@ -1,6 +1,5 @@
 // revisions: base extended
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/issue-76826.rs b/src/test/ui/generic-associated-types/issue-76826.rs
index 28eb3b0e750e..ead78453ecfe 100644
--- a/src/test/ui/generic-associated-types/issue-76826.rs
+++ b/src/test/ui/generic-associated-types/issue-76826.rs
@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(generic_associated_types)]
-
 pub trait Iter {
     type Item<'a> where Self: 'a;
 
diff --git a/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.rs b/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.rs
index 850d83be6845..fd3b967d9d77 100644
--- a/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.rs
+++ b/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.rs
@@ -1,9 +1,7 @@
-// Test for diagnostics when we have mismatched lifetime due to implict 'static lifetime in GATs
+// Test for diagnostics when we have mismatched lifetime due to implicit 'static lifetime in GATs
 
 // check-fail
 
-#![feature(generic_associated_types)]
-
 pub trait A {}
 impl A for &dyn A {}
 impl A for Box<dyn A> {}
diff --git a/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.stderr b/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.stderr
index d487f19ba749..86e0f5745440 100644
--- a/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.stderr
+++ b/src/test/ui/generic-associated-types/issue-78113-lifetime-mismatch-dyn-trait-box.stderr
@@ -1,22 +1,22 @@
 error: incompatible lifetime on type
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:17:18
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:15:18
    |
 LL |     type T<'a> = Box<dyn A + 'a>;
    |                  ^^^^^^^^^^^^^^^
    |
 note: because this has an unmet lifetime requirement
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:12:17
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:10:17
    |
 LL |     type T<'a>: A;
    |                 ^ introduces a `'static` lifetime requirement
 note: the lifetime `'a` as defined here...
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:17:12
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:15:12
    |
 LL |     type T<'a> = Box<dyn A + 'a>;
    |            ^^
    = note: ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
 note: this has an implicit `'static` lifetime requirement
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:9:20
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:7:20
    |
 LL | impl A for Box<dyn A> {}
    |                    ^
@@ -26,51 +26,51 @@ LL | impl A for Box<dyn A + '_> {}
    |                      ++++
 
 error: incompatible lifetime on type
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:27:18
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:25:18
    |
 LL |     type T<'a> = Box<dyn A + 'a>;
    |                  ^^^^^^^^^^^^^^^
    |
 note: because this has an unmet lifetime requirement
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:23:17
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:21:17
    |
 LL |     type T<'a>: C;
    |                 ^ introduces a `'static` lifetime requirement
 note: the lifetime `'a` as defined here...
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:27:12
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:25:12
    |
 LL |     type T<'a> = Box<dyn A + 'a>;
    |            ^^
 note: ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:21:1
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:19:1
    |
 LL | impl C for Box<dyn A + 'static> {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: incompatible lifetime on type
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:37:18
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:35:18
    |
 LL |     type T<'a> = (Box<dyn A + 'a>, Box<dyn A + 'a>);
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: because this has an unmet lifetime requirement
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:33:17
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:31:17
    |
 LL |     type T<'a>: E;
    |                 ^ introduces a `'static` lifetime requirement
 note: the lifetime `'a` as defined here...
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:37:12
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:35:12
    |
 LL |     type T<'a> = (Box<dyn A + 'a>, Box<dyn A + 'a>);
    |            ^^
    = note: ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
 note: this has an implicit `'static` lifetime requirement
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:31:21
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:29:21
    |
 LL | impl E for (Box<dyn A>, Box<dyn A>) {}
    |                     ^
 note: this has an implicit `'static` lifetime requirement
-  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:31:33
+  --> $DIR/issue-78113-lifetime-mismatch-dyn-trait-box.rs:29:33
    |
 LL | impl E for (Box<dyn A>, Box<dyn A>) {}
    |                                 ^
diff --git a/src/test/ui/generic-associated-types/issue-78671.base.stderr b/src/test/ui/generic-associated-types/issue-78671.base.stderr
index 6bcd004b1a92..514f8d45a15f 100644
--- a/src/test/ui/generic-associated-types/issue-78671.base.stderr
+++ b/src/test/ui/generic-associated-types/issue-78671.base.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `CollectionFamily::Member`
-  --> $DIR/issue-78671.rs:11:47
+  --> $DIR/issue-78671.rs:10:47
    |
 LL |     Box::new(Family) as &dyn CollectionFamily<Member=usize>
    |                                               ^^^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-78671.rs:8:10
+  --> $DIR/issue-78671.rs:7:10
    |
 LL |     type Member<T>;
    |          ^^^^^^ -
@@ -15,13 +15,13 @@ LL |     Box::new(Family) as &dyn CollectionFamily<Member<T>=usize>
    |                                               ~~~~~~~~~
 
 error[E0038]: the trait `CollectionFamily` cannot be made into an object
-  --> $DIR/issue-78671.rs:11:25
+  --> $DIR/issue-78671.rs:10:25
    |
 LL |     Box::new(Family) as &dyn CollectionFamily<Member=usize>
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `CollectionFamily` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-78671.rs:8:10
+  --> $DIR/issue-78671.rs:7:10
    |
 LL | trait CollectionFamily {
    |       ---------------- this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/issue-78671.extended.stderr b/src/test/ui/generic-associated-types/issue-78671.extended.stderr
index f1b48933516f..6fa09a4c7e59 100644
--- a/src/test/ui/generic-associated-types/issue-78671.extended.stderr
+++ b/src/test/ui/generic-associated-types/issue-78671.extended.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `CollectionFamily::Member`
-  --> $DIR/issue-78671.rs:11:47
+  --> $DIR/issue-78671.rs:10:47
    |
 LL |     Box::new(Family) as &dyn CollectionFamily<Member=usize>
    |                                               ^^^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-78671.rs:8:10
+  --> $DIR/issue-78671.rs:7:10
    |
 LL |     type Member<T>;
    |          ^^^^^^ -
diff --git a/src/test/ui/generic-associated-types/issue-78671.rs b/src/test/ui/generic-associated-types/issue-78671.rs
index c09dac28bda6..327b0c14ae86 100644
--- a/src/test/ui/generic-associated-types/issue-78671.rs
+++ b/src/test/ui/generic-associated-types/issue-78671.rs
@@ -1,6 +1,5 @@
 // revisions: base extended
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/issue-79422.base.stderr b/src/test/ui/generic-associated-types/issue-79422.base.stderr
index 0ed75ba1efc2..3c1a29d48b2f 100644
--- a/src/test/ui/generic-associated-types/issue-79422.base.stderr
+++ b/src/test/ui/generic-associated-types/issue-79422.base.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `MapLike::VRefCont`
-  --> $DIR/issue-79422.rs:48:36
+  --> $DIR/issue-79422.rs:47:36
    |
 LL |         as Box<dyn MapLike<u8, u8, VRefCont = dyn RefCont<'_, u8>>>;
    |                                    ^^^^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-79422.rs:24:10
+  --> $DIR/issue-79422.rs:23:10
    |
 LL |     type VRefCont<'a>: RefCont<'a, V> where Self: 'a;
    |          ^^^^^^^^ --
@@ -15,13 +15,13 @@ LL |         as Box<dyn MapLike<u8, u8, VRefCont<'a> = dyn RefCont<'_, u8>>>;
    |                                    ~~~~~~~~~~~~
 
 error[E0038]: the trait `MapLike` cannot be made into an object
-  --> $DIR/issue-79422.rs:48:12
+  --> $DIR/issue-79422.rs:47:12
    |
 LL |         as Box<dyn MapLike<u8, u8, VRefCont = dyn RefCont<'_, u8>>>;
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `MapLike` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-79422.rs:24:10
+  --> $DIR/issue-79422.rs:23:10
    |
 LL | trait MapLike<K, V> {
    |       ------- this trait cannot be made into an object...
@@ -30,13 +30,13 @@ LL |     type VRefCont<'a>: RefCont<'a, V> where Self: 'a;
    = help: consider moving `VRefCont` to another trait
 
 error[E0038]: the trait `MapLike` cannot be made into an object
-  --> $DIR/issue-79422.rs:45:13
+  --> $DIR/issue-79422.rs:44:13
    |
 LL |     let m = Box::new(std::collections::BTreeMap::<u8, u8>::new())
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `MapLike` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-79422.rs:24:10
+  --> $DIR/issue-79422.rs:23:10
    |
 LL | trait MapLike<K, V> {
    |       ------- this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/issue-79422.extended.stderr b/src/test/ui/generic-associated-types/issue-79422.extended.stderr
index 9bcbd7471684..58c921bf09f6 100644
--- a/src/test/ui/generic-associated-types/issue-79422.extended.stderr
+++ b/src/test/ui/generic-associated-types/issue-79422.extended.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `MapLike::VRefCont`
-  --> $DIR/issue-79422.rs:48:36
+  --> $DIR/issue-79422.rs:47:36
    |
 LL |         as Box<dyn MapLike<u8, u8, VRefCont = dyn RefCont<'_, u8>>>;
    |                                    ^^^^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-79422.rs:24:10
+  --> $DIR/issue-79422.rs:23:10
    |
 LL |     type VRefCont<'a>: RefCont<'a, V> where Self: 'a;
    |          ^^^^^^^^ --
@@ -15,13 +15,13 @@ LL |         as Box<dyn MapLike<u8, u8, VRefCont<'a> = dyn RefCont<'_, u8>>>;
    |                                    ~~~~~~~~~~~~
 
 error[E0271]: type mismatch resolving `<BTreeMap<u8, u8> as MapLike<u8, u8>>::VRefCont<'_> == (dyn RefCont<'_, u8> + 'static)`
-  --> $DIR/issue-79422.rs:45:13
+  --> $DIR/issue-79422.rs:44:13
    |
 LL |     let m = Box::new(std::collections::BTreeMap::<u8, u8>::new())
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `<BTreeMap<u8, u8> as MapLike<u8, u8>>::VRefCont<'_> == (dyn RefCont<'_, u8> + 'static)`
    |
 note: expected this to be `(dyn RefCont<'_, u8> + 'static)`
-  --> $DIR/issue-79422.rs:29:25
+  --> $DIR/issue-79422.rs:28:25
    |
 LL |     type VRefCont<'a> = &'a V where Self: 'a;
    |                         ^^^^^
diff --git a/src/test/ui/generic-associated-types/issue-79422.rs b/src/test/ui/generic-associated-types/issue-79422.rs
index 7749975e6872..a52dd792dda2 100644
--- a/src/test/ui/generic-associated-types/issue-79422.rs
+++ b/src/test/ui/generic-associated-types/issue-79422.rs
@@ -1,6 +1,5 @@
 // revisions: base extended
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/issue-79636-1.rs b/src/test/ui/generic-associated-types/issue-79636-1.rs
index 6d73fd68dbed..a89039b5c720 100644
--- a/src/test/ui/generic-associated-types/issue-79636-1.rs
+++ b/src/test/ui/generic-associated-types/issue-79636-1.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Monad {
     type Unwrapped;
     type Wrapped<B>;
diff --git a/src/test/ui/generic-associated-types/issue-79636-1.stderr b/src/test/ui/generic-associated-types/issue-79636-1.stderr
index 1ecb862827fd..155477048cad 100644
--- a/src/test/ui/generic-associated-types/issue-79636-1.stderr
+++ b/src/test/ui/generic-associated-types/issue-79636-1.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `Monad::Wrapped`
-  --> $DIR/issue-79636-1.rs:15:34
+  --> $DIR/issue-79636-1.rs:13:34
    |
 LL |     MInner: Monad<Unwrapped = A, Wrapped = MOuter::Wrapped<A>>,
    |                                  ^^^^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `B`
-  --> $DIR/issue-79636-1.rs:5:10
+  --> $DIR/issue-79636-1.rs:3:10
    |
 LL |     type Wrapped<B>;
    |          ^^^^^^^ -
diff --git a/src/test/ui/generic-associated-types/issue-79636-2.rs b/src/test/ui/generic-associated-types/issue-79636-2.rs
index cdaf2e483411..ff5ff38c968d 100644
--- a/src/test/ui/generic-associated-types/issue-79636-2.rs
+++ b/src/test/ui/generic-associated-types/issue-79636-2.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait SomeTrait {
     type Wrapped<A>: SomeTrait;
 
diff --git a/src/test/ui/generic-associated-types/issue-79636-2.stderr b/src/test/ui/generic-associated-types/issue-79636-2.stderr
index ae61b7b104e8..6a36bfc37f24 100644
--- a/src/test/ui/generic-associated-types/issue-79636-2.stderr
+++ b/src/test/ui/generic-associated-types/issue-79636-2.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `SomeTrait::Wrapped`
-  --> $DIR/issue-79636-2.rs:11:18
+  --> $DIR/issue-79636-2.rs:9:18
    |
 LL |     W: SomeTrait<Wrapped = W>,
    |                  ^^^^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `A`
-  --> $DIR/issue-79636-2.rs:4:10
+  --> $DIR/issue-79636-2.rs:2:10
    |
 LL |     type Wrapped<A>: SomeTrait;
    |          ^^^^^^^ -
diff --git a/src/test/ui/generic-associated-types/issue-80433-reduced.rs b/src/test/ui/generic-associated-types/issue-80433-reduced.rs
index f15d4d8b1385..44831a995c66 100644
--- a/src/test/ui/generic-associated-types/issue-80433-reduced.rs
+++ b/src/test/ui/generic-associated-types/issue-80433-reduced.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 struct E {}
 
 trait TestMut {
diff --git a/src/test/ui/generic-associated-types/issue-80433.rs b/src/test/ui/generic-associated-types/issue-80433.rs
index 6a1fe7519a84..05ff82fa7d5d 100644
--- a/src/test/ui/generic-associated-types/issue-80433.rs
+++ b/src/test/ui/generic-associated-types/issue-80433.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 #[derive(Default)]
 struct E<T> {
     data: T,
diff --git a/src/test/ui/generic-associated-types/issue-80433.stderr b/src/test/ui/generic-associated-types/issue-80433.stderr
index d8c210dcf7e9..20a407dd4125 100644
--- a/src/test/ui/generic-associated-types/issue-80433.stderr
+++ b/src/test/ui/generic-associated-types/issue-80433.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `TestMut::Output`
-  --> $DIR/issue-80433.rs:23:47
+  --> $DIR/issue-80433.rs:21:47
    |
 LL | fn test_simpler<'a>(dst: &'a mut impl TestMut<Output = &'a mut f32>)
    |                                               ^^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-80433.rs:9:10
+  --> $DIR/issue-80433.rs:7:10
    |
 LL |     type Output<'a>;
    |          ^^^^^^ --
diff --git a/src/test/ui/generic-associated-types/issue-81487.rs b/src/test/ui/generic-associated-types/issue-81487.rs
index 7f399c4f9a2d..0d19a75bb7ff 100644
--- a/src/test/ui/generic-associated-types/issue-81487.rs
+++ b/src/test/ui/generic-associated-types/issue-81487.rs
@@ -1,7 +1,5 @@
 // build-pass
 
-#![feature(generic_associated_types)]
-
 trait Trait {
     type Ref<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.rs b/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.rs
index fa2f86242257..a7cc9a6053e4 100644
--- a/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.rs
+++ b/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.rs
@@ -1,7 +1,5 @@
 // Regression test for #81712.
 
-#![feature(generic_associated_types)]
-
 trait A {
     type BType: B<AType = Self>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.stderr b/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.stderr
index 86c99c32fc1a..c8961e28ede4 100644
--- a/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.stderr
+++ b/src/test/ui/generic-associated-types/issue-81712-cyclic-traits.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `C::DType`
-  --> $DIR/issue-81712-cyclic-traits.rs:16:19
+  --> $DIR/issue-81712-cyclic-traits.rs:14:19
    |
 LL |     type CType: C<DType = Self>;
    |                   ^^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-81712-cyclic-traits.rs:13:10
+  --> $DIR/issue-81712-cyclic-traits.rs:11:10
    |
 LL |     type DType<T>: D<T, CType = Self>;
    |          ^^^^^ -
diff --git a/src/test/ui/generic-associated-types/issue-81862.rs b/src/test/ui/generic-associated-types/issue-81862.rs
index e457bca0c096..bde828b775b5 100644
--- a/src/test/ui/generic-associated-types/issue-81862.rs
+++ b/src/test/ui/generic-associated-types/issue-81862.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait StreamingIterator {
     type Item<'a>;
     fn next(&mut self) -> Option<Self::Item>;
diff --git a/src/test/ui/generic-associated-types/issue-81862.stderr b/src/test/ui/generic-associated-types/issue-81862.stderr
index c664b3ee6683..ba798084673c 100644
--- a/src/test/ui/generic-associated-types/issue-81862.stderr
+++ b/src/test/ui/generic-associated-types/issue-81862.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `StreamingIterator::Item`
-  --> $DIR/issue-81862.rs:5:40
+  --> $DIR/issue-81862.rs:3:40
    |
 LL |     fn next(&mut self) -> Option<Self::Item>;
    |                                        ^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-81862.rs:4:10
+  --> $DIR/issue-81862.rs:2:10
    |
 LL |     type Item<'a>;
    |          ^^^^ --
diff --git a/src/test/ui/generic-associated-types/issue-84931.rs b/src/test/ui/generic-associated-types/issue-84931.rs
index 9e247de16320..4123ce9d4d94 100644
--- a/src/test/ui/generic-associated-types/issue-84931.rs
+++ b/src/test/ui/generic-associated-types/issue-84931.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 // check-fail
 
 trait StreamingIter {
diff --git a/src/test/ui/generic-associated-types/issue-84931.stderr b/src/test/ui/generic-associated-types/issue-84931.stderr
index 11c3dffde4b3..fffea98a449e 100644
--- a/src/test/ui/generic-associated-types/issue-84931.stderr
+++ b/src/test/ui/generic-associated-types/issue-84931.stderr
@@ -1,5 +1,5 @@
 error[E0309]: the parameter type `T` may not live long enough
-  --> $DIR/issue-84931.rs:15:21
+  --> $DIR/issue-84931.rs:14:21
    |
 LL |     type Item<'a> = &'a mut T;
    |                     ^^^^^^^^^- help: consider adding a where clause: `where T: 'a`
diff --git a/src/test/ui/generic-associated-types/issue-85921.rs b/src/test/ui/generic-associated-types/issue-85921.rs
index df59f497d784..d281ed9eedbc 100644
--- a/src/test/ui/generic-associated-types/issue-85921.rs
+++ b/src/test/ui/generic-associated-types/issue-85921.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Trait {
     type Assoc<'a>;
 
diff --git a/src/test/ui/generic-associated-types/issue-86218-2.rs b/src/test/ui/generic-associated-types/issue-86218-2.rs
new file mode 100644
index 000000000000..63c839ea8712
--- /dev/null
+++ b/src/test/ui/generic-associated-types/issue-86218-2.rs
@@ -0,0 +1,23 @@
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+
+pub trait Stream {
+    type Item;
+}
+
+impl Stream for () {
+    type Item = i32;
+}
+
+trait Yay<AdditionalValue> {
+    type InnerStream<'s>: Stream<Item = i32> + 's;
+    fn foo<'s>() -> Self::InnerStream<'s>;
+}
+
+impl<T> Yay<T> for () {
+    type InnerStream<'s> = impl Stream<Item = i32> + 's;
+    fn foo<'s>() -> Self::InnerStream<'s> { () }
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/bugs/issue-86218.rs b/src/test/ui/generic-associated-types/issue-86218.rs
similarity index 65%
rename from src/test/ui/generic-associated-types/bugs/issue-86218.rs
rename to src/test/ui/generic-associated-types/issue-86218.rs
index fb62c10a9e38..b2c3071f06b1 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-86218.rs
+++ b/src/test/ui/generic-associated-types/issue-86218.rs
@@ -1,9 +1,5 @@
-// check-fail
-// known-bug: #86218
+// check-pass
 
-// This should pass, but seems to run into a TAIT issue.
-
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 pub trait Stream {
@@ -21,7 +17,8 @@ trait Yay<AdditionalValue> {
 
 impl<'a> Yay<&'a ()> for () {
     type InnerStream<'s> = impl Stream<Item = i32> + 's;
-    fn foo<'s>() -> Self::InnerStream<'s> { todo!() }
+    //^ ERROR does not fulfill the required lifetime
+    fn foo<'s>() -> Self::InnerStream<'s> { () }
 }
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-86483.rs b/src/test/ui/generic-associated-types/issue-86483.rs
index 07dd0bffd468..70267637ae9d 100644
--- a/src/test/ui/generic-associated-types/issue-86483.rs
+++ b/src/test/ui/generic-associated-types/issue-86483.rs
@@ -4,8 +4,6 @@
 //
 // check-pass
 
-#![feature(generic_associated_types)]
-
 pub trait IceIce<T>
 where
     for<'a> T: 'a,
diff --git a/src/test/ui/generic-associated-types/issue-86787.rs b/src/test/ui/generic-associated-types/issue-86787.rs
index 0f8096c8a7c1..96075ca503da 100644
--- a/src/test/ui/generic-associated-types/issue-86787.rs
+++ b/src/test/ui/generic-associated-types/issue-86787.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 // check-fail
 
 enum Either<L, R> {
diff --git a/src/test/ui/generic-associated-types/issue-86787.stderr b/src/test/ui/generic-associated-types/issue-86787.stderr
index d4b2267d3ddc..f34c63cf72e1 100644
--- a/src/test/ui/generic-associated-types/issue-86787.stderr
+++ b/src/test/ui/generic-associated-types/issue-86787.stderr
@@ -1,5 +1,5 @@
 error: missing required bound on `TRef`
-  --> $DIR/issue-86787.rs:11:5
+  --> $DIR/issue-86787.rs:10:5
    |
 LL |     type TRef<'a>;
    |     ^^^^^^^^^^^^^-
diff --git a/src/test/ui/generic-associated-types/issue-87258_a.rs b/src/test/ui/generic-associated-types/issue-87258_a.rs
index c65f3fb2aa0a..9ab683d3dc9e 100644
--- a/src/test/ui/generic-associated-types/issue-87258_a.rs
+++ b/src/test/ui/generic-associated-types/issue-87258_a.rs
@@ -1,5 +1,4 @@
 #![feature(type_alias_impl_trait)]
-#![feature(generic_associated_types)]
 
 // See https://github.com/rust-lang/rust/issues/87258#issuecomment-883293367
 
diff --git a/src/test/ui/generic-associated-types/issue-87258_a.stderr b/src/test/ui/generic-associated-types/issue-87258_a.stderr
index db3a5c819cbf..fa0748a280b6 100644
--- a/src/test/ui/generic-associated-types/issue-87258_a.stderr
+++ b/src/test/ui/generic-associated-types/issue-87258_a.stderr
@@ -1,5 +1,5 @@
 error: unconstrained opaque type
-  --> $DIR/issue-87258_a.rs:18:26
+  --> $DIR/issue-87258_a.rs:17:26
    |
 LL |     type FooFuture<'a> = impl Trait1;
    |                          ^^^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/issue-87258_b.rs b/src/test/ui/generic-associated-types/issue-87258_b.rs
index f59e0d766594..7b7610b21c7d 100644
--- a/src/test/ui/generic-associated-types/issue-87258_b.rs
+++ b/src/test/ui/generic-associated-types/issue-87258_b.rs
@@ -1,5 +1,4 @@
 #![feature(type_alias_impl_trait)]
-#![feature(generic_associated_types)]
 
 // See https://github.com/rust-lang/rust/issues/87258#issuecomment-883293367
 
diff --git a/src/test/ui/generic-associated-types/issue-87258_b.stderr b/src/test/ui/generic-associated-types/issue-87258_b.stderr
index 9faccc96124b..0ee665f38ad0 100644
--- a/src/test/ui/generic-associated-types/issue-87258_b.stderr
+++ b/src/test/ui/generic-associated-types/issue-87258_b.stderr
@@ -1,5 +1,5 @@
 error: unconstrained opaque type
-  --> $DIR/issue-87258_b.rs:17:49
+  --> $DIR/issue-87258_b.rs:16:49
    |
 LL | type Helper<'xenon, 'yttrium, KABOOM: Trait2> = impl Trait1;
    |                                                 ^^^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/issue-87429-2.rs b/src/test/ui/generic-associated-types/issue-87429-2.rs
index d35bb098abdf..feb43ee5aa4a 100644
--- a/src/test/ui/generic-associated-types/issue-87429-2.rs
+++ b/src/test/ui/generic-associated-types/issue-87429-2.rs
@@ -4,8 +4,6 @@
 
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Family {
     type Member<'a, C: Eq>: for<'b> MyBound<'b, C>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs
index 9ee07c2f1e1c..2006f9bc74df 100644
--- a/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs
+++ b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.rs
@@ -1,7 +1,6 @@
 // check-fail
 
 #![feature(associated_type_defaults)]
-#![feature(generic_associated_types)]
 
 trait Family {
     // Fine, i32: PartialEq<i32>
diff --git a/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr
index c6fa02cb9a6b..b1abe012be23 100644
--- a/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr
+++ b/src/test/ui/generic-associated-types/issue-87429-associated-type-default.stderr
@@ -1,12 +1,12 @@
 error[E0277]: can't compare `Foo` with `Foo`
-  --> $DIR/issue-87429-associated-type-default.rs:14:60
+  --> $DIR/issue-87429-associated-type-default.rs:13:60
    |
 LL |     type Member<'a>: for<'b> PartialEq<Self::Member<'b>> = Foo;
    |                                                            ^^^ no implementation for `Foo == Foo`
    |
    = help: the trait `PartialEq` is not implemented for `Foo`
 note: required by a bound in `Family2::Member`
-  --> $DIR/issue-87429-associated-type-default.rs:14:22
+  --> $DIR/issue-87429-associated-type-default.rs:13:22
    |
 LL |     type Member<'a>: for<'b> PartialEq<Self::Member<'b>> = Foo;
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Family2::Member`
diff --git a/src/test/ui/generic-associated-types/issue-87429-specialization.rs b/src/test/ui/generic-associated-types/issue-87429-specialization.rs
index b365e07feb28..6e31f1b21e5c 100644
--- a/src/test/ui/generic-associated-types/issue-87429-specialization.rs
+++ b/src/test/ui/generic-associated-types/issue-87429-specialization.rs
@@ -2,7 +2,6 @@
 
 #![feature(specialization)]
 //~^ WARN incomplete
-#![feature(generic_associated_types)]
 
 trait Family {
     type Member<'a>: for<'b> PartialEq<Self::Member<'b>>;
diff --git a/src/test/ui/generic-associated-types/issue-87429-specialization.stderr b/src/test/ui/generic-associated-types/issue-87429-specialization.stderr
index 015e0c7792fe..d8e889aecef7 100644
--- a/src/test/ui/generic-associated-types/issue-87429-specialization.stderr
+++ b/src/test/ui/generic-associated-types/issue-87429-specialization.stderr
@@ -9,14 +9,14 @@ LL | #![feature(specialization)]
    = help: consider using `min_specialization` instead, which is more stable and complete
 
 error[E0277]: can't compare `Foo` with `Foo`
-  --> $DIR/issue-87429-specialization.rs:21:31
+  --> $DIR/issue-87429-specialization.rs:20:31
    |
 LL |     default type Member<'a> = Foo;
    |                               ^^^ no implementation for `Foo == Foo`
    |
    = help: the trait `PartialEq` is not implemented for `Foo`
 note: required by a bound in `Family::Member`
-  --> $DIR/issue-87429-specialization.rs:8:22
+  --> $DIR/issue-87429-specialization.rs:7:22
    |
 LL |     type Member<'a>: for<'b> PartialEq<Self::Member<'b>>;
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Family::Member`
diff --git a/src/test/ui/generic-associated-types/issue-87429.rs b/src/test/ui/generic-associated-types/issue-87429.rs
index f905348ae32a..56394823cc51 100644
--- a/src/test/ui/generic-associated-types/issue-87429.rs
+++ b/src/test/ui/generic-associated-types/issue-87429.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Family {
     type Member<'a>: for<'b> PartialEq<Self::Member<'b>>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-87748.rs b/src/test/ui/generic-associated-types/issue-87748.rs
index 1a1ab9bf8a4e..6cbe3d902233 100644
--- a/src/test/ui/generic-associated-types/issue-87748.rs
+++ b/src/test/ui/generic-associated-types/issue-87748.rs
@@ -3,8 +3,6 @@
 
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait MyTrait {
     type Assoc<'a, 'b> where 'b: 'a;
     fn do_sth(arg: Self::Assoc<'_, '_>);
diff --git a/src/test/ui/generic-associated-types/issue-87750.rs b/src/test/ui/generic-associated-types/issue-87750.rs
index 89bd79ac2991..0a11a0f3ae0e 100644
--- a/src/test/ui/generic-associated-types/issue-87750.rs
+++ b/src/test/ui/generic-associated-types/issue-87750.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait PointerFamily {
     type Pointer<T>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-87750.stderr b/src/test/ui/generic-associated-types/issue-87750.stderr
index 854541f3d8fd..b358ca273ca7 100644
--- a/src/test/ui/generic-associated-types/issue-87750.stderr
+++ b/src/test/ui/generic-associated-types/issue-87750.stderr
@@ -1,5 +1,5 @@
 error[E0275]: overflow evaluating the requirement `Node<i32, RcFamily>: Sized`
-  --> $DIR/issue-87750.rs:20:16
+  --> $DIR/issue-87750.rs:18:16
    |
 LL |     let _list: <RcFamily as PointerFamily>::Pointer<Node<i32, RcFamily>>;
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/issue-88287.rs b/src/test/ui/generic-associated-types/issue-88287.rs
index 4952a082586d..82188493d52b 100644
--- a/src/test/ui/generic-associated-types/issue-88287.rs
+++ b/src/test/ui/generic-associated-types/issue-88287.rs
@@ -1,6 +1,5 @@
 // edition:2018
 
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use std::future::Future;
diff --git a/src/test/ui/generic-associated-types/issue-88287.stderr b/src/test/ui/generic-associated-types/issue-88287.stderr
index 5241d85a5f96..1b84cce62292 100644
--- a/src/test/ui/generic-associated-types/issue-88287.stderr
+++ b/src/test/ui/generic-associated-types/issue-88287.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the size for values of type `A` cannot be known at compilation time
-  --> $DIR/issue-88287.rs:35:9
+  --> $DIR/issue-88287.rs:34:9
    |
 LL | type SearchFutureTy<'f, A, B: 'f>
    |                         - this type parameter needs to be `std::marker::Sized`
@@ -8,7 +8,7 @@ LL |         async move { todo!() }
    |         ^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
    |
 note: required by a bound in `<T as SearchableResourceExt<Criteria>>`
-  --> $DIR/issue-88287.rs:25:6
+  --> $DIR/issue-88287.rs:24:6
    |
 LL | impl<T, Criteria> SearchableResourceExt<Criteria> for T
    |      ^ required by this bound in `<T as SearchableResourceExt<Criteria>>`
diff --git a/src/test/ui/generic-associated-types/issue-88360.rs b/src/test/ui/generic-associated-types/issue-88360.rs
index 8ee98201aba7..c02690618d0e 100644
--- a/src/test/ui/generic-associated-types/issue-88360.rs
+++ b/src/test/ui/generic-associated-types/issue-88360.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait GatTrait {
     type Gat<'a> where Self: 'a;
 
diff --git a/src/test/ui/generic-associated-types/issue-88360.stderr b/src/test/ui/generic-associated-types/issue-88360.stderr
index 5f769d799faa..cd3750344dda 100644
--- a/src/test/ui/generic-associated-types/issue-88360.stderr
+++ b/src/test/ui/generic-associated-types/issue-88360.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-88360.rs:15:9
+  --> $DIR/issue-88360.rs:13:9
    |
 LL | trait SuperTrait<T>
    |                  - this type parameter
diff --git a/src/test/ui/generic-associated-types/issue-88405.rs b/src/test/ui/generic-associated-types/issue-88405.rs
index 4a405bd3625c..8dad6a89fd05 100644
--- a/src/test/ui/generic-associated-types/issue-88405.rs
+++ b/src/test/ui/generic-associated-types/issue-88405.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait SomeTrait {}
 trait OtherTrait {
     type Item;
diff --git a/src/test/ui/generic-associated-types/issue-88459.rs b/src/test/ui/generic-associated-types/issue-88459.rs
index 3b26a180152c..07d7bc06d08e 100644
--- a/src/test/ui/generic-associated-types/issue-88459.rs
+++ b/src/test/ui/generic-associated-types/issue-88459.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait Trait {
     type Assoc<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-88595.rs b/src/test/ui/generic-associated-types/issue-88595.rs
index e0796dfecbbc..24641ee1f781 100644
--- a/src/test/ui/generic-associated-types/issue-88595.rs
+++ b/src/test/ui/generic-associated-types/issue-88595.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/issue-88595.stderr b/src/test/ui/generic-associated-types/issue-88595.stderr
index 79d3479af8c8..bcefc8066851 100644
--- a/src/test/ui/generic-associated-types/issue-88595.stderr
+++ b/src/test/ui/generic-associated-types/issue-88595.stderr
@@ -1,11 +1,11 @@
 error: non-defining opaque type use in defining scope
-  --> $DIR/issue-88595.rs:21:35
+  --> $DIR/issue-88595.rs:20:35
    |
 LL |     fn a(&'a self) -> Self::B<'a> {}
    |                                   ^^
    |
 note: lifetime used multiple times
-  --> $DIR/issue-88595.rs:18:6
+  --> $DIR/issue-88595.rs:17:6
    |
 LL | impl<'a> A<'a> for C {
    |      ^^
diff --git a/src/test/ui/generic-associated-types/issue-89352.rs b/src/test/ui/generic-associated-types/issue-89352.rs
index d9c656d5f58a..1896d0c87f4c 100644
--- a/src/test/ui/generic-associated-types/issue-89352.rs
+++ b/src/test/ui/generic-associated-types/issue-89352.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 use std::marker::PhantomData;
 
 pub trait GenAssoc<T> {
diff --git a/src/test/ui/generic-associated-types/issue-90014.rs b/src/test/ui/generic-associated-types/issue-90014.rs
index f110b069383d..55db95a6d819 100644
--- a/src/test/ui/generic-associated-types/issue-90014.rs
+++ b/src/test/ui/generic-associated-types/issue-90014.rs
@@ -1,6 +1,5 @@
 // edition:2018
 
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 use std::future::Future;
diff --git a/src/test/ui/generic-associated-types/issue-90014.stderr b/src/test/ui/generic-associated-types/issue-90014.stderr
index 457c582e8c8d..2d3f4a6af7e0 100644
--- a/src/test/ui/generic-associated-types/issue-90014.stderr
+++ b/src/test/ui/generic-associated-types/issue-90014.stderr
@@ -1,5 +1,5 @@
 error[E0477]: the type `&mut ()` does not fulfill the required lifetime
-  --> $DIR/issue-90014.rs:14:20
+  --> $DIR/issue-90014.rs:13:20
    |
 LL |     type Fut<'a> where Self: 'a;
    |     ------------ definition of `Fut` from trait
@@ -8,7 +8,7 @@ LL |     type Fut<'a> = impl Future<Output = ()>;
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^- help: try copying this clause from the trait: `where Self: 'a`
    |
 note: type must outlive the lifetime `'a` as defined here
-  --> $DIR/issue-90014.rs:14:14
+  --> $DIR/issue-90014.rs:13:14
    |
 LL |     type Fut<'a> = impl Future<Output = ()>;
    |              ^^
diff --git a/src/test/ui/generic-associated-types/issue-90729.rs b/src/test/ui/generic-associated-types/issue-90729.rs
index 98295cce8d58..bcec2e32121d 100644
--- a/src/test/ui/generic-associated-types/issue-90729.rs
+++ b/src/test/ui/generic-associated-types/issue-90729.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 use std::marker::PhantomData;
 
 pub trait Type {
diff --git a/src/test/ui/generic-associated-types/issue-91139.migrate.stderr b/src/test/ui/generic-associated-types/issue-91139.migrate.stderr
index b424d9a2fdb0..690160577cd9 100644
--- a/src/test/ui/generic-associated-types/issue-91139.migrate.stderr
+++ b/src/test/ui/generic-associated-types/issue-91139.migrate.stderr
@@ -1,13 +1,8 @@
-error[E0311]: the parameter type `T` may not live long enough
-  --> $DIR/issue-91139.rs:27:12
+error: expected identifier, found `<<`
+  --> $DIR/issue-91139.rs:1:1
    |
-LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
-   |
-help: consider adding an explicit lifetime bound...
-   |
-LL | fn foo<T: 'a>() {
-   |         ++++
+LL | <<<<<<< HEAD
+   | ^^ expected identifier
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generic-associated-types/issue-91139.rs b/src/test/ui/generic-associated-types/issue-91139.rs
index 40eef11f058e..5fc6071c9396 100644
--- a/src/test/ui/generic-associated-types/issue-91139.rs
+++ b/src/test/ui/generic-associated-types/issue-91139.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Foo<T> {
     type Type<'a>
     where
diff --git a/src/test/ui/generic-associated-types/issue-91139.stderr b/src/test/ui/generic-associated-types/issue-91139.stderr
index b789b3a42f33..8bbe98fa1e50 100644
--- a/src/test/ui/generic-associated-types/issue-91139.stderr
+++ b/src/test/ui/generic-associated-types/issue-91139.stderr
@@ -1,41 +1,41 @@
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:12
+  --> $DIR/issue-91139.rs:14:12
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:12
+  --> $DIR/issue-91139.rs:14:12
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:12
+  --> $DIR/issue-91139.rs:14:12
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:12
+  --> $DIR/issue-91139.rs:14:12
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:58
+  --> $DIR/issue-91139.rs:14:58
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |                                                          ^^^^^^^^^
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:58
+  --> $DIR/issue-91139.rs:14:58
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |                                                          ^^^^^^^^^
 
 error[E0310]: the parameter type `T` may not live long enough
-  --> $DIR/issue-91139.rs:16:58
+  --> $DIR/issue-91139.rs:14:58
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |                                                          ^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
@@ -46,13 +46,13 @@ LL | fn foo<T: 'static>() {
    |         +++++++++
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:58
+  --> $DIR/issue-91139.rs:14:58
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |                                                          ^^^^^^^^^
 
 error: `T` does not live long enough
-  --> $DIR/issue-91139.rs:16:58
+  --> $DIR/issue-91139.rs:14:58
    |
 LL |     let _: for<'a> fn(<() as Foo<T>>::Type<'a>, &'a T) = |_, _| ();
    |                                                          ^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/issue-91883.rs b/src/test/ui/generic-associated-types/issue-91883.rs
index 3d4585a44df8..e870e08a3a2b 100644
--- a/src/test/ui/generic-associated-types/issue-91883.rs
+++ b/src/test/ui/generic-associated-types/issue-91883.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 use std::fmt::Debug;
 use std::marker::PhantomData;
 
diff --git a/src/test/ui/generic-associated-types/issue-91883.stderr b/src/test/ui/generic-associated-types/issue-91883.stderr
index baf4889cc1dd..1cfc2aaf1613 100644
--- a/src/test/ui/generic-associated-types/issue-91883.stderr
+++ b/src/test/ui/generic-associated-types/issue-91883.stderr
@@ -1,5 +1,5 @@
 error[E0478]: lifetime bound not satisfied
-  --> $DIR/issue-91883.rs:32:24
+  --> $DIR/issue-91883.rs:30:24
    |
 LL |     type Cursor<'tx>: Cursor<'tx>
    |     ----------------------------- definition of `Cursor` from trait
@@ -8,12 +8,12 @@ LL |     type Cursor<'tx> = CursorImpl<'tx>;
    |                        ^^^^^^^^^^^^^^^- help: try copying these clauses from the trait: `where 'db: 'tx, Self: 'tx`
    |
 note: lifetime parameter instantiated with the lifetime `'db` as defined here
-  --> $DIR/issue-91883.rs:31:6
+  --> $DIR/issue-91883.rs:29:6
    |
 LL | impl<'db> Transaction<'db> for TransactionImpl<'db> {
    |      ^^^
 note: but lifetime parameter must outlive the lifetime `'tx` as defined here
-  --> $DIR/issue-91883.rs:32:17
+  --> $DIR/issue-91883.rs:30:17
    |
 LL |     type Cursor<'tx> = CursorImpl<'tx>;
    |                 ^^^
diff --git a/src/test/ui/generic-associated-types/issue-92033.rs b/src/test/ui/generic-associated-types/issue-92033.rs
index 1d5f7d5c0099..d111580b860a 100644
--- a/src/test/ui/generic-associated-types/issue-92033.rs
+++ b/src/test/ui/generic-associated-types/issue-92033.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 struct Texture;
 
 trait Surface {
diff --git a/src/test/ui/generic-associated-types/issue-92033.stderr b/src/test/ui/generic-associated-types/issue-92033.stderr
index 6dd901027d7b..cd7eed25421e 100644
--- a/src/test/ui/generic-associated-types/issue-92033.stderr
+++ b/src/test/ui/generic-associated-types/issue-92033.stderr
@@ -1,5 +1,5 @@
 error[E0477]: the type `&'s Texture` does not fulfill the required lifetime
-  --> $DIR/issue-92033.rs:22:28
+  --> $DIR/issue-92033.rs:20:28
    |
 LL |     type TextureIter<'a>: Iterator<Item = &'a Texture>
    |     -------------------------------------------------- definition of `TextureIter` from trait
@@ -8,7 +8,7 @@ LL |     type TextureIter<'a> = std::option::IntoIter<&'a Texture>;
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- help: try copying this clause from the trait: `where Self: 'a`
    |
 note: type must outlive the lifetime `'a` as defined here
-  --> $DIR/issue-92033.rs:22:22
+  --> $DIR/issue-92033.rs:20:22
    |
 LL |     type TextureIter<'a> = std::option::IntoIter<&'a Texture>;
    |                      ^^
diff --git a/src/test/ui/generic-associated-types/issue-92096.migrate.stderr b/src/test/ui/generic-associated-types/issue-92096.migrate.stderr
index c74161cd3e05..ce1fd6dd9831 100644
--- a/src/test/ui/generic-associated-types/issue-92096.migrate.stderr
+++ b/src/test/ui/generic-associated-types/issue-92096.migrate.stderr
@@ -1,5 +1,5 @@
 error[E0311]: the parameter type `C` may not live long enough
-  --> $DIR/issue-92096.rs:20:33
+  --> $DIR/issue-92096.rs:19:33
    |
 LL | fn call_connect<C>(c: &'_ C) -> impl '_ + Future + Send
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `C` will meet its required lifetime bounds
@@ -10,7 +10,7 @@ LL |     C: Client + Send + Sync + 'a,
    |                             ++++
 
 error[E0311]: the parameter type `C` may not live long enough
-  --> $DIR/issue-92096.rs:20:33
+  --> $DIR/issue-92096.rs:19:33
    |
 LL | fn call_connect<C>(c: &'_ C) -> impl '_ + Future + Send
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `C` will meet its required lifetime bounds
diff --git a/src/test/ui/generic-associated-types/issue-92096.rs b/src/test/ui/generic-associated-types/issue-92096.rs
index 377b8164ad50..e285af6660ec 100644
--- a/src/test/ui/generic-associated-types/issue-92096.rs
+++ b/src/test/ui/generic-associated-types/issue-92096.rs
@@ -1,7 +1,5 @@
 // edition:2018
 
-#![feature(generic_associated_types)]
-
 use std::future::Future;
 
 trait Client {
diff --git a/src/test/ui/generic-associated-types/issue-92096.stderr b/src/test/ui/generic-associated-types/issue-92096.stderr
index ca61a0f435e9..91a06d5acde1 100644
--- a/src/test/ui/generic-associated-types/issue-92096.stderr
+++ b/src/test/ui/generic-associated-types/issue-92096.stderr
@@ -1,5 +1,5 @@
 error: `C` does not live long enough
-  --> $DIR/issue-92096.rs:19:5
+  --> $DIR/issue-92096.rs:17:5
    |
 LL |     async move { c.connect().await }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/issue-92280.rs b/src/test/ui/generic-associated-types/issue-92280.rs
index 81d000f1076c..9284beea33e5 100644
--- a/src/test/ui/generic-associated-types/issue-92280.rs
+++ b/src/test/ui/generic-associated-types/issue-92280.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
 #![allow(non_camel_case_types)]
 
 trait HasAssoc {
diff --git a/src/test/ui/generic-associated-types/issue-92954.rs b/src/test/ui/generic-associated-types/issue-92954.rs
index 95c090ff4e90..22ce8f9fe3b8 100644
--- a/src/test/ui/generic-associated-types/issue-92954.rs
+++ b/src/test/ui/generic-associated-types/issue-92954.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 pub trait Foo {
     type Assoc<'c>;
     fn function() -> for<'x> fn(Self::Assoc<'x>);
diff --git a/src/test/ui/generic-associated-types/issue-93141.rs b/src/test/ui/generic-associated-types/issue-93141.rs
index 39ca77d13db9..48c78b9c0676 100644
--- a/src/test/ui/generic-associated-types/issue-93141.rs
+++ b/src/test/ui/generic-associated-types/issue-93141.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 pub trait Fooey: Sized {
     type Context<'c> where Self: 'c;
 }
diff --git a/src/test/ui/generic-associated-types/issue-93262.rs b/src/test/ui/generic-associated-types/issue-93262.rs
index adc6aa8fa1af..a7bcd111dfff 100644
--- a/src/test/ui/generic-associated-types/issue-93262.rs
+++ b/src/test/ui/generic-associated-types/issue-93262.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 pub trait Trait {
     type Assoc<'a> where Self: 'a;
 }
diff --git a/src/test/ui/generic-associated-types/issue-93340.rs b/src/test/ui/generic-associated-types/issue-93340.rs
index d065bde88c41..4662fda537b5 100644
--- a/src/test/ui/generic-associated-types/issue-93340.rs
+++ b/src/test/ui/generic-associated-types/issue-93340.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 pub trait Scalar: 'static {
     type RefType<'a>: ScalarRef<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/issue-93341.rs b/src/test/ui/generic-associated-types/issue-93341.rs
index e96a768ecda8..737b2bbdb245 100644
--- a/src/test/ui/generic-associated-types/issue-93341.rs
+++ b/src/test/ui/generic-associated-types/issue-93341.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
 use std::marker::PhantomData;
 
 pub struct Id<'id>(PhantomData<fn(&'id ()) -> &'id ()>);
diff --git a/src/test/ui/generic-associated-types/issue-93342.rs b/src/test/ui/generic-associated-types/issue-93342.rs
index d8d7adac9516..d4422d5d1d72 100644
--- a/src/test/ui/generic-associated-types/issue-93342.rs
+++ b/src/test/ui/generic-associated-types/issue-93342.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 use std::marker::PhantomData;
 
 pub trait Scalar: 'static {
diff --git a/src/test/ui/generic-associated-types/issue-93874.rs b/src/test/ui/generic-associated-types/issue-93874.rs
index f403d75167d8..30956655ad40 100644
--- a/src/test/ui/generic-associated-types/issue-93874.rs
+++ b/src/test/ui/generic-associated-types/issue-93874.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 pub trait Build {
     type Output<O>;
     fn build<O>(self, input: O) -> Self::Output<O>;
diff --git a/src/test/ui/generic-associated-types/issue-95305.rs b/src/test/ui/generic-associated-types/issue-95305.rs
index e2f1710fa281..6c3ec20e7a05 100644
--- a/src/test/ui/generic-associated-types/issue-95305.rs
+++ b/src/test/ui/generic-associated-types/issue-95305.rs
@@ -2,7 +2,6 @@
 // Forbid it for now but proper support might be added
 // at some point in the future.
 
-#![feature(generic_associated_types)]
 #![feature(anonymous_lifetime_in_impl_trait)]
 trait Foo {
     type Item<'a>;
diff --git a/src/test/ui/generic-associated-types/issue-95305.stderr b/src/test/ui/generic-associated-types/issue-95305.stderr
index d8557525f54e..eb15cbc620ac 100644
--- a/src/test/ui/generic-associated-types/issue-95305.stderr
+++ b/src/test/ui/generic-associated-types/issue-95305.stderr
@@ -1,5 +1,5 @@
 error[E0637]: `'_` cannot be used here
-  --> $DIR/issue-95305.rs:11:26
+  --> $DIR/issue-95305.rs:10:26
    |
 LL | fn foo(x: &impl Foo<Item<'_> = u32>) { }
    |                          ^^ `'_` is a reserved lifetime name
diff --git a/src/test/ui/generic-associated-types/iterable.rs b/src/test/ui/generic-associated-types/iterable.rs
index af0049891b69..8ad351bd343c 100644
--- a/src/test/ui/generic-associated-types/iterable.rs
+++ b/src/test/ui/generic-associated-types/iterable.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // run-pass
 
 trait Iterable {
diff --git a/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.rs b/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.rs
index 655abd18da1c..36974b3df5e6 100644
--- a/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.rs
+++ b/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.rs
@@ -1,8 +1,6 @@
 // Test that the predicate printed in an unresolved method error prints the
 // generics for a generic associated type.
 
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<T>;
 }
diff --git a/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.stderr b/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.stderr
index d9dc77ac8eb4..baef38f6b804 100644
--- a/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.stderr
+++ b/src/test/ui/generic-associated-types/method-unsatified-assoc-type-predicate.stderr
@@ -1,5 +1,5 @@
 error[E0599]: the method `f` exists for struct `S`, but its trait bounds were not satisfied
-  --> $DIR/method-unsatified-assoc-type-predicate.rs:30:7
+  --> $DIR/method-unsatified-assoc-type-predicate.rs:28:7
    |
 LL | struct S;
    | --------
@@ -12,7 +12,7 @@ LL |     a.f();
    |       ^ method cannot be called on `S` due to unsatisfied trait bounds
    |
 note: trait bound `<S as X>::Y<i32> = i32` was not satisfied
-  --> $DIR/method-unsatified-assoc-type-predicate.rs:14:11
+  --> $DIR/method-unsatified-assoc-type-predicate.rs:12:11
    |
 LL | impl<T: X<Y<i32> = i32>> M for T {}
    |           ^^^^^^^^^^^^   -     -
diff --git a/src/test/ui/generic-associated-types/missing-bounds.fixed b/src/test/ui/generic-associated-types/missing-bounds.fixed
index 2315810a47ac..ee758f19ec10 100644
--- a/src/test/ui/generic-associated-types/missing-bounds.fixed
+++ b/src/test/ui/generic-associated-types/missing-bounds.fixed
@@ -24,7 +24,7 @@ impl<B: Add + Add<Output = B>> Add for C<B> {
 
 struct D<B>(B);
 
-impl<B: std::ops::Add<Output=B>> Add for D<B> {
+impl<B: std::ops::Add<Output = B>> Add for D<B> {
     type Output = Self;
 
     fn add(self, rhs: Self) -> Self {
diff --git a/src/test/ui/generic-associated-types/missing-bounds.stderr b/src/test/ui/generic-associated-types/missing-bounds.stderr
index 138c642dd795..c913483a8747 100644
--- a/src/test/ui/generic-associated-types/missing-bounds.stderr
+++ b/src/test/ui/generic-associated-types/missing-bounds.stderr
@@ -66,8 +66,8 @@ LL |         Self(self.0 + rhs.0)
    |
 help: consider restricting type parameter `B`
    |
-LL | impl<B: std::ops::Add<Output=B>> Add for D<B> {
-   |       +++++++++++++++++++++++++
+LL | impl<B: std::ops::Add<Output = B>> Add for D<B> {
+   |       +++++++++++++++++++++++++++
 
 error[E0308]: mismatched types
   --> $DIR/missing-bounds.rs:42:14
diff --git a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs
index 8171dc0ae28d..de9cad308014 100644
--- a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs
+++ b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.rs
@@ -1,7 +1,5 @@
 // check-fail
 
-#![feature(generic_associated_types)]
-
 trait Foo {
     type Assoc<'a, 'b>;
 }
diff --git a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr
index edd1f9367d12..ffdba6676bf8 100644
--- a/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr
+++ b/src/test/ui/generic-associated-types/missing-where-clause-on-trait.stderr
@@ -1,5 +1,5 @@
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/missing-where-clause-on-trait.rs:9:39
+  --> $DIR/missing-where-clause-on-trait.rs:7:39
    |
 LL |     type Assoc<'a, 'b>;
    |     ------------------ definition of `Assoc` from trait
diff --git a/src/test/ui/generic-associated-types/missing_lifetime_args.rs b/src/test/ui/generic-associated-types/missing_lifetime_args.rs
index cd918157f7c8..78def80925ad 100644
--- a/src/test/ui/generic-associated-types/missing_lifetime_args.rs
+++ b/src/test/ui/generic-associated-types/missing_lifetime_args.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<'a, 'b>;
 }
diff --git a/src/test/ui/generic-associated-types/missing_lifetime_args.stderr b/src/test/ui/generic-associated-types/missing_lifetime_args.stderr
index 7cf3f4b737e0..0ad1f1f8c4d3 100644
--- a/src/test/ui/generic-associated-types/missing_lifetime_args.stderr
+++ b/src/test/ui/generic-associated-types/missing_lifetime_args.stderr
@@ -1,11 +1,11 @@
 error[E0107]: missing generics for associated type `X::Y`
-  --> $DIR/missing_lifetime_args.rs:13:32
+  --> $DIR/missing_lifetime_args.rs:11:32
    |
 LL | fn foo<'c, 'd>(_arg: Box<dyn X<Y = (&'c u32, &'d u32)>>) {}
    |                                ^ expected 2 lifetime arguments
    |
 note: associated type defined here, with 2 lifetime parameters: `'a`, `'b`
-  --> $DIR/missing_lifetime_args.rs:4:10
+  --> $DIR/missing_lifetime_args.rs:2:10
    |
 LL |     type Y<'a, 'b>;
    |          ^ --  --
@@ -15,7 +15,7 @@ LL | fn foo<'c, 'd>(_arg: Box<dyn X<Y<'c, 'd> = (&'c u32, &'d u32)>>) {}
    |                                ~~~~~~~~~
 
 error[E0107]: this struct takes 3 lifetime arguments but 2 lifetime arguments were supplied
-  --> $DIR/missing_lifetime_args.rs:16:26
+  --> $DIR/missing_lifetime_args.rs:14:26
    |
 LL | fn bar<'a, 'b, 'c>(_arg: Foo<'a, 'b>) {}
    |                          ^^^ --  -- supplied 2 lifetime arguments
@@ -23,7 +23,7 @@ LL | fn bar<'a, 'b, 'c>(_arg: Foo<'a, 'b>) {}
    |                          expected 3 lifetime arguments
    |
 note: struct defined here, with 3 lifetime parameters: `'a`, `'b`, `'c`
-  --> $DIR/missing_lifetime_args.rs:7:8
+  --> $DIR/missing_lifetime_args.rs:5:8
    |
 LL | struct Foo<'a, 'b, 'c> {
    |        ^^^ --  --  --
@@ -33,7 +33,7 @@ LL | fn bar<'a, 'b, 'c>(_arg: Foo<'a, 'b, 'a>) {}
    |                                    ++++
 
 error[E0107]: this struct takes 3 lifetime arguments but 1 lifetime argument was supplied
-  --> $DIR/missing_lifetime_args.rs:19:16
+  --> $DIR/missing_lifetime_args.rs:17:16
    |
 LL | fn f<'a>(_arg: Foo<'a>) {}
    |                ^^^ -- supplied 1 lifetime argument
@@ -41,7 +41,7 @@ LL | fn f<'a>(_arg: Foo<'a>) {}
    |                expected 3 lifetime arguments
    |
 note: struct defined here, with 3 lifetime parameters: `'a`, `'b`, `'c`
-  --> $DIR/missing_lifetime_args.rs:7:8
+  --> $DIR/missing_lifetime_args.rs:5:8
    |
 LL | struct Foo<'a, 'b, 'c> {
    |        ^^^ --  --  --
diff --git a/src/test/ui/generic-associated-types/missing_lifetime_const.rs b/src/test/ui/generic-associated-types/missing_lifetime_const.rs
index e3e78dd96f62..8b174b9e971e 100644
--- a/src/test/ui/generic-associated-types/missing_lifetime_const.rs
+++ b/src/test/ui/generic-associated-types/missing_lifetime_const.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Foo {
     type Assoc<'a, const N: usize>;
 }
diff --git a/src/test/ui/generic-associated-types/missing_lifetime_const.stderr b/src/test/ui/generic-associated-types/missing_lifetime_const.stderr
index 5d50637bd013..62d2e9f49dde 100644
--- a/src/test/ui/generic-associated-types/missing_lifetime_const.stderr
+++ b/src/test/ui/generic-associated-types/missing_lifetime_const.stderr
@@ -1,11 +1,11 @@
 error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
-  --> $DIR/missing_lifetime_const.rs:8:24
+  --> $DIR/missing_lifetime_const.rs:6:24
    |
 LL |     let _: <T as Foo>::Assoc<3>;
    |                        ^^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/missing_lifetime_const.rs:4:10
+  --> $DIR/missing_lifetime_const.rs:2:10
    |
 LL |     type Assoc<'a, const N: usize>;
    |          ^^^^^ --
diff --git a/src/test/ui/generic-associated-types/parameter_number_and_kind.rs b/src/test/ui/generic-associated-types/parameter_number_and_kind.rs
index 0508cc2daeae..8428e7763fb4 100644
--- a/src/test/ui/generic-associated-types/parameter_number_and_kind.rs
+++ b/src/test/ui/generic-associated-types/parameter_number_and_kind.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 trait Foo {
diff --git a/src/test/ui/generic-associated-types/parameter_number_and_kind.stderr b/src/test/ui/generic-associated-types/parameter_number_and_kind.stderr
index 53d76fd22012..c20b9669e814 100644
--- a/src/test/ui/generic-associated-types/parameter_number_and_kind.stderr
+++ b/src/test/ui/generic-associated-types/parameter_number_and_kind.stderr
@@ -1,5 +1,5 @@
 error[E0107]: this associated type takes 1 lifetime argument but 2 lifetime arguments were supplied
-  --> $DIR/parameter_number_and_kind.rs:12:24
+  --> $DIR/parameter_number_and_kind.rs:11:24
    |
 LL |     type FErr1 = Self::E<'static, 'static>;
    |                        ^          ------- help: remove this lifetime argument
@@ -7,19 +7,19 @@ LL |     type FErr1 = Self::E<'static, 'static>;
    |                        expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/parameter_number_and_kind.rs:9:10
+  --> $DIR/parameter_number_and_kind.rs:8:10
    |
 LL |     type E<'a, T>;
    |          ^ --
 
 error[E0107]: this associated type takes 1 generic argument but 0 generic arguments were supplied
-  --> $DIR/parameter_number_and_kind.rs:12:24
+  --> $DIR/parameter_number_and_kind.rs:11:24
    |
 LL |     type FErr1 = Self::E<'static, 'static>;
    |                        ^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/parameter_number_and_kind.rs:9:10
+  --> $DIR/parameter_number_and_kind.rs:8:10
    |
 LL |     type E<'a, T>;
    |          ^     -
@@ -29,7 +29,7 @@ LL |     type FErr1 = Self::E<'static, 'static, T>;
    |                                          +++
 
 error[E0107]: this associated type takes 1 generic argument but 2 generic arguments were supplied
-  --> $DIR/parameter_number_and_kind.rs:15:27
+  --> $DIR/parameter_number_and_kind.rs:14:27
    |
 LL |     type FErr2<T> = Self::E<'static, T, u32>;
    |                           ^             --- help: remove this generic argument
@@ -37,7 +37,7 @@ LL |     type FErr2<T> = Self::E<'static, T, u32>;
    |                           expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/parameter_number_and_kind.rs:9:10
+  --> $DIR/parameter_number_and_kind.rs:8:10
    |
 LL |     type E<'a, T>;
    |          ^     -
diff --git a/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.rs b/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.rs
index 6ca0bc6ddbc9..c1381025ac2a 100644
--- a/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.rs
+++ b/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(associated_type_defaults)]
 
 // FIXME(#44265) add tests for type-generic and const-genertic associated types.
diff --git a/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.stderr b/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.stderr
index 1458bf0c4a49..fdd6d305ab27 100644
--- a/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.stderr
+++ b/src/test/ui/generic-associated-types/parameter_number_and_kind_impl.stderr
@@ -1,5 +1,5 @@
 error[E0195]: lifetime parameters or bounds on type `A` do not match the trait declaration
-  --> $DIR/parameter_number_and_kind_impl.rs:15:11
+  --> $DIR/parameter_number_and_kind_impl.rs:14:11
    |
 LL |     type A<'a>;
    |           ---- lifetimes in impl do not match this type in trait
@@ -8,7 +8,7 @@ LL |     type A = u32;
    |           ^ lifetimes do not match type in trait
 
 error[E0049]: type `B` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/parameter_number_and_kind_impl.rs:17:12
+  --> $DIR/parameter_number_and_kind_impl.rs:16:12
    |
 LL |     type B<'a, 'b>;
    |            --  --
@@ -21,7 +21,7 @@ LL |     type B<'a, T> = Vec<T>;
    |            found 1 type parameter
 
 error[E0195]: lifetime parameters or bounds on type `C` do not match the trait declaration
-  --> $DIR/parameter_number_and_kind_impl.rs:19:11
+  --> $DIR/parameter_number_and_kind_impl.rs:18:11
    |
 LL |     type C;
    |           - lifetimes in impl do not match this type in trait
@@ -30,7 +30,7 @@ LL |     type C<'a> = u32;
    |           ^^^^ lifetimes do not match type in trait
 
 error[E0049]: type `A` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/parameter_number_and_kind_impl.rs:26:12
+  --> $DIR/parameter_number_and_kind_impl.rs:25:12
    |
 LL |     type A<'a>;
    |            -- expected 0 type parameters
@@ -39,7 +39,7 @@ LL |     type A<T> = u32;
    |            ^ found 1 type parameter
 
 error[E0195]: lifetime parameters or bounds on type `B` do not match the trait declaration
-  --> $DIR/parameter_number_and_kind_impl.rs:28:11
+  --> $DIR/parameter_number_and_kind_impl.rs:27:11
    |
 LL |     type B<'a, 'b>;
    |           -------- lifetimes in impl do not match this type in trait
@@ -48,7 +48,7 @@ LL |     type B<'a> = u32;
    |           ^^^^ lifetimes do not match type in trait
 
 error[E0049]: type `C` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/parameter_number_and_kind_impl.rs:30:12
+  --> $DIR/parameter_number_and_kind_impl.rs:29:12
    |
 LL |     type C;
    |           - expected 0 type parameters
diff --git a/src/test/ui/generic-associated-types/parse/in-trait-impl.rs b/src/test/ui/generic-associated-types/parse/in-trait-impl.rs
index 7f4775ddbb07..767098835c48 100644
--- a/src/test/ui/generic-associated-types/parse/in-trait-impl.rs
+++ b/src/test/ui/generic-associated-types/parse/in-trait-impl.rs
@@ -1,8 +1,6 @@
 // check-pass
 // compile-flags: -Z parse-only
 
-#![feature(generic_associated_types)]
-
 impl<T> Baz for T where T: Foo {
     type Quux<'a> = <T as Foo>::Bar<'a, 'static>;
 }
diff --git a/src/test/ui/generic-associated-types/parse/in-trait.rs b/src/test/ui/generic-associated-types/parse/in-trait.rs
index d438795eb1d9..6628aac37430 100644
--- a/src/test/ui/generic-associated-types/parse/in-trait.rs
+++ b/src/test/ui/generic-associated-types/parse/in-trait.rs
@@ -1,8 +1,6 @@
 // check-pass
 // compile-flags: -Z parse-only
 
-#![feature(generic_associated_types)]
-
 use std::ops::Deref;
 use std::fmt::Debug;
 
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-expected-token.rs b/src/test/ui/generic-associated-types/parse/trait-path-expected-token.rs
index be85598b7bfa..cbb05189201d 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-expected-token.rs
+++ b/src/test/ui/generic-associated-types/parse/trait-path-expected-token.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-expected-token.stderr b/src/test/ui/generic-associated-types/parse/trait-path-expected-token.stderr
index 2b265e921616..53d5f9de6575 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-expected-token.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-expected-token.stderr
@@ -1,5 +1,5 @@
 error: expected one of `!`, `(`, `+`, `,`, `::`, `<`, or `>`, found `=`
-  --> $DIR/trait-path-expected-token.rs:7:33
+  --> $DIR/trait-path-expected-token.rs:5:33
    |
 LL | fn f1<'a>(arg : Box<dyn X<Y = B = &'a ()>>) {}
    |                               - ^ expected one of 7 possible tokens
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-expressions.rs b/src/test/ui/generic-associated-types/parse/trait-path-expressions.rs
index d57c2813b38a..9183ec4976b0 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-expressions.rs
+++ b/src/test/ui/generic-associated-types/parse/trait-path-expressions.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 mod error1 {
   trait X {
       type Y<'a>;
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr b/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr
index 272afc10b17b..cf2b1763fc9d 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr
@@ -1,5 +1,5 @@
 error: expected expression, found `)`
-  --> $DIR/trait-path-expressions.rs:8:39
+  --> $DIR/trait-path-expressions.rs:6:39
    |
 LL |   fn f1<'a>(arg : Box<dyn X< 1 = 32 >>) {}
    |                              -        ^ expected expression
@@ -7,7 +7,7 @@ LL |   fn f1<'a>(arg : Box<dyn X< 1 = 32 >>) {}
    |                              while parsing a const generic argument starting here
 
 error: expected one of `,`, `:`, or `>`, found `=`
-  --> $DIR/trait-path-expressions.rs:18:36
+  --> $DIR/trait-path-expressions.rs:16:36
    |
 LL |   fn f2<'a>(arg : Box<dyn X< { 1 } = 32 >>) {}
    |                                  - ^ expected one of `,`, `:`, or `>`
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.rs b/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.rs
index 7914864807ce..ecabf8943ea3 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.rs
+++ b/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.stderr b/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.stderr
index 3ace774a041c..10ceccedcac1 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-missing-gen_arg.stderr
@@ -1,5 +1,5 @@
 error: expected one of `>`, a const expression, lifetime, or type, found `:`
-  --> $DIR/trait-path-missing-gen_arg.rs:8:30
+  --> $DIR/trait-path-missing-gen_arg.rs:6:30
    |
 LL |   fn f1<'a>(arg : Box<dyn X< : 32 >>) {}
    |                              ^ expected one of `>`, a const expression, lifetime, or type
@@ -10,13 +10,13 @@ LL |   fn f1<'a>(arg : Box<{ dyn X< : 32 } >>) {}
    |                       +             +
 
 error: expected parameter name, found `>`
-  --> $DIR/trait-path-missing-gen_arg.rs:8:36
+  --> $DIR/trait-path-missing-gen_arg.rs:6:36
    |
 LL |   fn f1<'a>(arg : Box<dyn X< : 32 >>) {}
    |                                    ^ expected parameter name
 
 error: expected one of `!`, `)`, `+`, `,`, or `::`, found `>`
-  --> $DIR/trait-path-missing-gen_arg.rs:8:36
+  --> $DIR/trait-path-missing-gen_arg.rs:6:36
    |
 LL |   fn f1<'a>(arg : Box<dyn X< : 32 >>) {}
    |                                    ^
@@ -25,7 +25,7 @@ LL |   fn f1<'a>(arg : Box<dyn X< : 32 >>) {}
    |                                    help: missing `,`
 
 error: expected one of `>`, a const expression, lifetime, or type, found `=`
-  --> $DIR/trait-path-missing-gen_arg.rs:16:30
+  --> $DIR/trait-path-missing-gen_arg.rs:14:30
    |
 LL |   fn f1<'a>(arg : Box<dyn X< = 32 >>) {}
    |                            - ^ expected one of `>`, a const expression, lifetime, or type
@@ -33,7 +33,7 @@ LL |   fn f1<'a>(arg : Box<dyn X< = 32 >>) {}
    |                            maybe try to close unmatched angle bracket
 
 error[E0747]: constant provided when a type was expected
-  --> $DIR/trait-path-missing-gen_arg.rs:8:23
+  --> $DIR/trait-path-missing-gen_arg.rs:6:23
    |
 LL |   fn f1<'a>(arg : Box<dyn X< : 32 >>) {}
    |                       ^^^^^^^^^^^
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-segments.rs b/src/test/ui/generic-associated-types/parse/trait-path-segments.rs
index e943f075f534..458e203eb3ce 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-segments.rs
+++ b/src/test/ui/generic-associated-types/parse/trait-path-segments.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 const _: () = {
     trait X {
         type Y<'a>;
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr b/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr
index 7394393c05e2..8bc737d67520 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr
@@ -1,5 +1,5 @@
 error: expected one of `!`, `(`, `+`, `,`, `::`, `:`, `<`, or `>`, found `=`
-  --> $DIR/trait-path-segments.rs:8:36
+  --> $DIR/trait-path-segments.rs:6:36
    |
 LL |     fn f1<'a>(arg : Box<dyn X<X::Y = u32>>) {}
    |                                  - ^ expected one of 8 possible tokens
@@ -12,7 +12,7 @@ LL |     fn f1<'a>(arg : Box<dyn X<X::Y> = u32>>) {}
    |                                   +
 
 error: expected one of `,`, `::`, `:`, or `>`, found `=`
-  --> $DIR/trait-path-segments.rs:19:35
+  --> $DIR/trait-path-segments.rs:17:35
    |
 LL |     impl<T : X<<Self as X>::Y<'a> = &'a u32>> Z for T {}
    |                                 - ^ expected one of `,`, `::`, `:`, or `>`
@@ -25,7 +25,7 @@ LL |     impl<T : X<<Self as X>::Y<'a>> = &'a u32>> Z for T {}
    |                                  +
 
 error: expected one of `!`, `+`, `,`, `::`, `:`, or `>`, found `=`
-  --> $DIR/trait-path-segments.rs:30:25
+  --> $DIR/trait-path-segments.rs:28:25
    |
 LL |     impl<T : X<X::Y<'a> = &'a u32>> Z for T {}
    |                       - ^ expected one of `!`, `+`, `,`, `::`, `:`, or `>`
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.rs b/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.rs
index 4846af96d32a..1622b92aa0cc 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.rs
+++ b/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.stderr b/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.stderr
index 46ddcb635187..e00a414efb9b 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-type-error-once-implemented.stderr
@@ -1,11 +1,11 @@
 error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
-  --> $DIR/trait-path-type-error-once-implemented.rs:8:29
+  --> $DIR/trait-path-type-error-once-implemented.rs:6:29
    |
 LL |   fn f2<'a>(arg : Box<dyn X<Y<1> = &'a ()>>) {}
    |                             ^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/trait-path-type-error-once-implemented.rs:4:10
+  --> $DIR/trait-path-type-error-once-implemented.rs:2:10
    |
 LL |     type Y<'a>;
    |          ^ --
@@ -15,7 +15,7 @@ LL |   fn f2<'a>(arg : Box<dyn X<Y<'a, 1> = &'a ()>>) {}
    |                               +++
 
 error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/trait-path-type-error-once-implemented.rs:8:29
+  --> $DIR/trait-path-type-error-once-implemented.rs:6:29
    |
 LL |   fn f2<'a>(arg : Box<dyn X<Y<1> = &'a ()>>) {}
    |                             ^--- help: remove these generics
@@ -23,7 +23,7 @@ LL |   fn f2<'a>(arg : Box<dyn X<Y<1> = &'a ()>>) {}
    |                             expected 0 generic arguments
    |
 note: associated type defined here, with 0 generic parameters
-  --> $DIR/trait-path-type-error-once-implemented.rs:4:10
+  --> $DIR/trait-path-type-error-once-implemented.rs:2:10
    |
 LL |     type Y<'a>;
    |          ^
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-types.rs b/src/test/ui/generic-associated-types/parse/trait-path-types.rs
index 856253cc7fab..74a00342ff4b 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-types.rs
+++ b/src/test/ui/generic-associated-types/parse/trait-path-types.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<'a>;
 }
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-types.stderr b/src/test/ui/generic-associated-types/parse/trait-path-types.stderr
index fe9ed579e34a..8f7a73c95b65 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-types.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-types.stderr
@@ -1,5 +1,5 @@
 error: expected one of `,`, `:`, or `>`, found `=`
-  --> $DIR/trait-path-types.rs:8:37
+  --> $DIR/trait-path-types.rs:6:37
    |
 LL |   fn f<'a>(arg : Box<dyn X< [u8; 1] = u32>>) {}
    |                                   - ^ expected one of `,`, `:`, or `>`
@@ -12,7 +12,7 @@ LL |   fn f<'a>(arg : Box<dyn X< [u8; 1]> = u32>>) {}
    |                                    +
 
 error: expected one of `,`, `:`, or `>`, found `=`
-  --> $DIR/trait-path-types.rs:13:37
+  --> $DIR/trait-path-types.rs:11:37
    |
 LL |   fn f1<'a>(arg : Box<dyn X<(Y<'a>) = &'a ()>>) {}
    |                                   - ^ expected one of `,`, `:`, or `>`
@@ -25,7 +25,7 @@ LL |   fn f1<'a>(arg : Box<dyn X<(Y<'a>)> = &'a ()>>) {}
    |                                    +
 
 error: expected one of `,`, `:`, or `>`, found `=`
-  --> $DIR/trait-path-types.rs:18:33
+  --> $DIR/trait-path-types.rs:16:33
    |
 LL |   fn f1<'a>(arg : Box<dyn X< 'a = u32 >>) {}
    |                              -- ^ expected one of `,`, `:`, or `>`
diff --git a/src/test/ui/generic-associated-types/pointer_family.rs b/src/test/ui/generic-associated-types/pointer_family.rs
index da86e7f27482..80827cd567b4 100644
--- a/src/test/ui/generic-associated-types/pointer_family.rs
+++ b/src/test/ui/generic-associated-types/pointer_family.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // check-pass
 
 use std::rc::Rc;
diff --git a/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs b/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs
index 794d677c8b65..58d57df63c1b 100644
--- a/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs
+++ b/src/test/ui/generic-associated-types/projection-bound-cycle-generic.rs
@@ -1,8 +1,6 @@
 // Like `projection-bound-cycle.rs` but this avoids using
 // `feature(trivial_bounds)`.
 
-#![feature(generic_associated_types)]
-
 trait Print {
     fn print();
 }
diff --git a/src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr b/src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr
index 2b57c439fe9a..27c1a82994a5 100644
--- a/src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr
+++ b/src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr
@@ -1,11 +1,11 @@
 error[E0275]: overflow evaluating the requirement `<T as Foo>::Item: Sized`
-  --> $DIR/projection-bound-cycle-generic.rs:44:18
+  --> $DIR/projection-bound-cycle-generic.rs:42:18
    |
 LL |     type Assoc = OnlySized<<T as Foo>::Item>;
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: required by a bound in `OnlySized`
-  --> $DIR/projection-bound-cycle-generic.rs:28:18
+  --> $DIR/projection-bound-cycle-generic.rs:26:18
    |
 LL | struct OnlySized<T> where T: Sized { f: T }
    |                  ^ required by this bound in `OnlySized`
diff --git a/src/test/ui/generic-associated-types/projection-bound-cycle.rs b/src/test/ui/generic-associated-types/projection-bound-cycle.rs
index 6564a3608ec0..4cad1f61319e 100644
--- a/src/test/ui/generic-associated-types/projection-bound-cycle.rs
+++ b/src/test/ui/generic-associated-types/projection-bound-cycle.rs
@@ -2,7 +2,6 @@
 // Make sure that we make sure that we don't allow arbitrary bounds to be
 // proven when a bound and a where clause of an associated type are the same.
 
-#![feature(generic_associated_types)]
 #![feature(trivial_bounds)]
 
 trait Print {
diff --git a/src/test/ui/generic-associated-types/projection-bound-cycle.stderr b/src/test/ui/generic-associated-types/projection-bound-cycle.stderr
index d9d0bf4274bd..a46518c80da7 100644
--- a/src/test/ui/generic-associated-types/projection-bound-cycle.stderr
+++ b/src/test/ui/generic-associated-types/projection-bound-cycle.stderr
@@ -1,11 +1,11 @@
 error[E0275]: overflow evaluating the requirement `<T as Foo>::Item: Sized`
-  --> $DIR/projection-bound-cycle.rs:46:18
+  --> $DIR/projection-bound-cycle.rs:45:18
    |
 LL |     type Assoc = OnlySized<<T as Foo>::Item>;
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: required by a bound in `OnlySized`
-  --> $DIR/projection-bound-cycle.rs:30:18
+  --> $DIR/projection-bound-cycle.rs:29:18
    |
 LL | struct OnlySized<T> where T: Sized { f: T }
    |                  ^ required by this bound in `OnlySized`
diff --git a/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.rs b/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.rs
index a40c0c2c4c74..8e4d5ca5e267 100644
--- a/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.rs
+++ b/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 pub trait X {
     type Y<'a> where Self: 'a;
     fn m(&self) -> Self::Y<'_>;
diff --git a/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr b/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr
index 4620aa34e84d..753ead48bf54 100644
--- a/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr
+++ b/src/test/ui/generic-associated-types/projection-type-lifetime-mismatch.stderr
@@ -1,5 +1,5 @@
 error: lifetime may not live long enough
-  --> $DIR/projection-type-lifetime-mismatch.rs:17:5
+  --> $DIR/projection-type-lifetime-mismatch.rs:15:5
    |
 LL | fn f(x: &impl for<'a> X<Y<'a> = &'a ()>) -> &'static () {
    |         - let's call the lifetime of this reference `'1`
@@ -7,7 +7,7 @@ LL |     x.m()
    |     ^^^^^ returning this value requires that `'1` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/projection-type-lifetime-mismatch.rs:22:5
+  --> $DIR/projection-type-lifetime-mismatch.rs:20:5
    |
 LL | fn g<T: for<'a> X<Y<'a> = &'a ()>>(x: &T) -> &'static () {
    |                                       - let's call the lifetime of this reference `'1`
@@ -15,7 +15,7 @@ LL |     x.m()
    |     ^^^^^ returning this value requires that `'1` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/projection-type-lifetime-mismatch.rs:27:5
+  --> $DIR/projection-type-lifetime-mismatch.rs:25:5
    |
 LL | fn h(x: &()) -> &'static () {
    |         - let's call the lifetime of this reference `'1`
diff --git a/src/test/ui/generic-associated-types/self-outlives-lint.rs b/src/test/ui/generic-associated-types/self-outlives-lint.rs
index 9bb42d4ff1c1..673891fc3d1b 100644
--- a/src/test/ui/generic-associated-types/self-outlives-lint.rs
+++ b/src/test/ui/generic-associated-types/self-outlives-lint.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // check-fail
 
 use std::fmt::Debug;
diff --git a/src/test/ui/generic-associated-types/self-outlives-lint.stderr b/src/test/ui/generic-associated-types/self-outlives-lint.stderr
index a43b35bd79c9..58172bf06b51 100644
--- a/src/test/ui/generic-associated-types/self-outlives-lint.stderr
+++ b/src/test/ui/generic-associated-types/self-outlives-lint.stderr
@@ -1,5 +1,5 @@
 error: missing required bound on `Item`
-  --> $DIR/self-outlives-lint.rs:9:5
+  --> $DIR/self-outlives-lint.rs:7:5
    |
 LL |     type Item<'x>;
    |     ^^^^^^^^^^^^^-
@@ -10,7 +10,7 @@ LL |     type Item<'x>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Out`
-  --> $DIR/self-outlives-lint.rs:25:5
+  --> $DIR/self-outlives-lint.rs:23:5
    |
 LL |     type Out<'x>;
    |     ^^^^^^^^^^^^-
@@ -21,7 +21,7 @@ LL |     type Out<'x>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Out`
-  --> $DIR/self-outlives-lint.rs:39:5
+  --> $DIR/self-outlives-lint.rs:37:5
    |
 LL |     type Out<'x>;
    |     ^^^^^^^^^^^^-
@@ -32,7 +32,7 @@ LL |     type Out<'x>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bounds on `Out`
-  --> $DIR/self-outlives-lint.rs:46:5
+  --> $DIR/self-outlives-lint.rs:44:5
    |
 LL |     type Out<'x, 'y>;
    |     ^^^^^^^^^^^^^^^^-
@@ -43,7 +43,7 @@ LL |     type Out<'x, 'y>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Out`
-  --> $DIR/self-outlives-lint.rs:61:5
+  --> $DIR/self-outlives-lint.rs:59:5
    |
 LL |     type Out<'x, D>;
    |     ^^^^^^^^^^^^^^^-
@@ -54,7 +54,7 @@ LL |     type Out<'x, D>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Out`
-  --> $DIR/self-outlives-lint.rs:77:5
+  --> $DIR/self-outlives-lint.rs:75:5
    |
 LL |     type Out<'x, D>;
    |     ^^^^^^^^^^^^^^^-
@@ -65,7 +65,7 @@ LL |     type Out<'x, D>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Out`
-  --> $DIR/self-outlives-lint.rs:92:5
+  --> $DIR/self-outlives-lint.rs:90:5
    |
 LL |     type Out<'x, D>;
    |     ^^^^^^^^^^^^^^^-
@@ -76,7 +76,7 @@ LL |     type Out<'x, D>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bounds on `Bar`
-  --> $DIR/self-outlives-lint.rs:114:5
+  --> $DIR/self-outlives-lint.rs:112:5
    |
 LL |     type Bar<'b>;
    |     ^^^^^^^^^^^^-
@@ -87,7 +87,7 @@ LL |     type Bar<'b>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Bar`
-  --> $DIR/self-outlives-lint.rs:122:5
+  --> $DIR/self-outlives-lint.rs:120:5
    |
 LL |     type Bar<'b>;
    |     ^^^^^^^^^^^^-
@@ -98,7 +98,7 @@ LL |     type Bar<'b>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Bar`
-  --> $DIR/self-outlives-lint.rs:129:5
+  --> $DIR/self-outlives-lint.rs:127:5
    |
 LL |     type Bar<'b>;
    |     ^^^^^^^^^^^^-
@@ -109,7 +109,7 @@ LL |     type Bar<'b>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Item`
-  --> $DIR/self-outlives-lint.rs:142:5
+  --> $DIR/self-outlives-lint.rs:140:5
    |
 LL |     type Item<'a>;
    |     ^^^^^^^^^^^^^-
@@ -120,7 +120,7 @@ LL |     type Item<'a>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Iterator`
-  --> $DIR/self-outlives-lint.rs:144:5
+  --> $DIR/self-outlives-lint.rs:142:5
    |
 LL |     type Iterator<'a>: Iterator<Item = Self::Item<'a>>;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
@@ -131,7 +131,7 @@ LL |     type Iterator<'a>: Iterator<Item = Self::Item<'a>>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Item`
-  --> $DIR/self-outlives-lint.rs:150:5
+  --> $DIR/self-outlives-lint.rs:148:5
    |
 LL |     type Item<'a>;
    |     ^^^^^^^^^^^^^-
@@ -142,7 +142,7 @@ LL |     type Item<'a>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Bar`
-  --> $DIR/self-outlives-lint.rs:159:5
+  --> $DIR/self-outlives-lint.rs:157:5
    |
 LL |     type Bar<'a, 'b>;
    |     ^^^^^^^^^^^^^^^^-
@@ -153,7 +153,7 @@ LL |     type Bar<'a, 'b>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Fut`
-  --> $DIR/self-outlives-lint.rs:175:5
+  --> $DIR/self-outlives-lint.rs:173:5
    |
 LL |     type Fut<'out>;
    |     ^^^^^^^^^^^^^^-
@@ -164,7 +164,7 @@ LL |     type Fut<'out>;
    = note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
 
 error: missing required bound on `Item`
-  --> $DIR/self-outlives-lint.rs:215:5
+  --> $DIR/self-outlives-lint.rs:213:5
    |
 LL |     type Item<'a>;
    |     ^^^^^^^^^^^^^-
diff --git a/src/test/ui/generic-associated-types/shadowing.rs b/src/test/ui/generic-associated-types/shadowing.rs
index 2a9763457df7..a05d6e14352b 100644
--- a/src/test/ui/generic-associated-types/shadowing.rs
+++ b/src/test/ui/generic-associated-types/shadowing.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Shadow<'a> {
     type Bar<'a>;
     //~^ ERROR lifetime name `'a` shadows a lifetime name that is already in scope
diff --git a/src/test/ui/generic-associated-types/shadowing.stderr b/src/test/ui/generic-associated-types/shadowing.stderr
index be765920975b..bb32684bc7b9 100644
--- a/src/test/ui/generic-associated-types/shadowing.stderr
+++ b/src/test/ui/generic-associated-types/shadowing.stderr
@@ -1,5 +1,5 @@
 error[E0496]: lifetime name `'a` shadows a lifetime name that is already in scope
-  --> $DIR/shadowing.rs:4:14
+  --> $DIR/shadowing.rs:2:14
    |
 LL | trait Shadow<'a> {
    |              -- first declared here
@@ -7,7 +7,7 @@ LL |     type Bar<'a>;
    |              ^^ lifetime `'a` already in scope
 
 error[E0496]: lifetime name `'a` shadows a lifetime name that is already in scope
-  --> $DIR/shadowing.rs:13:14
+  --> $DIR/shadowing.rs:11:14
    |
 LL | impl<'a> NoShadow<'a> for &'a u32 {
    |      -- first declared here
@@ -15,7 +15,7 @@ LL |     type Bar<'a> = i32;
    |              ^^ lifetime `'a` already in scope
 
 error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
-  --> $DIR/shadowing.rs:18:14
+  --> $DIR/shadowing.rs:16:14
    |
 LL | trait ShadowT<T> {
    |               - first use of `T`
@@ -23,7 +23,7 @@ LL |     type Bar<T>;
    |              ^ already used
 
 error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
-  --> $DIR/shadowing.rs:27:14
+  --> $DIR/shadowing.rs:25:14
    |
 LL | impl<T> NoShadowT<T> for Option<T> {
    |      - first use of `T`
diff --git a/src/test/ui/generic-associated-types/streaming_iterator.rs b/src/test/ui/generic-associated-types/streaming_iterator.rs
index e71b6805ad41..408b8dc99eb4 100644
--- a/src/test/ui/generic-associated-types/streaming_iterator.rs
+++ b/src/test/ui/generic-associated-types/streaming_iterator.rs
@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(generic_associated_types)]
-
 use std::fmt::Display;
 
 trait StreamingIterator {
diff --git a/src/test/ui/generic-associated-types/trait-objects.base.stderr b/src/test/ui/generic-associated-types/trait-objects.base.stderr
index 1df76a21bf9b..556422c272cf 100644
--- a/src/test/ui/generic-associated-types/trait-objects.base.stderr
+++ b/src/test/ui/generic-associated-types/trait-objects.base.stderr
@@ -1,11 +1,11 @@
 error[E0038]: the trait `StreamingIterator` cannot be made into an object
-  --> $DIR/trait-objects.rs:14:21
+  --> $DIR/trait-objects.rs:13:21
    |
 LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `StreamingIterator` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/trait-objects.rs:8:10
+  --> $DIR/trait-objects.rs:7:10
    |
 LL | trait StreamingIterator {
    |       ----------------- this trait cannot be made into an object...
diff --git a/src/test/ui/generic-associated-types/trait-objects.extended.stderr b/src/test/ui/generic-associated-types/trait-objects.extended.stderr
index 52d48d57859f..45b64d2b0248 100644
--- a/src/test/ui/generic-associated-types/trait-objects.extended.stderr
+++ b/src/test/ui/generic-associated-types/trait-objects.extended.stderr
@@ -1,5 +1,5 @@
 error[E0521]: borrowed data escapes outside of function
-  --> $DIR/trait-objects.rs:16:5
+  --> $DIR/trait-objects.rs:15:5
    |
 LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
    |             -  - let's call the lifetime of this reference `'1`
@@ -11,6 +11,8 @@ LL |     x.size_hint().0
    |     |
    |     `x` escapes the function body here
    |     argument requires that `'1` must outlive `'static`
+   |
+   = note: due to current limitations in the borrow checker, this implies a `'static` lifetime
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generic-associated-types/trait-objects.rs b/src/test/ui/generic-associated-types/trait-objects.rs
index c1da1e0a326d..17fed11bac36 100644
--- a/src/test/ui/generic-associated-types/trait-objects.rs
+++ b/src/test/ui/generic-associated-types/trait-objects.rs
@@ -1,6 +1,5 @@
 // revisions: base extended
 
-#![feature(generic_associated_types)]
 #![cfg_attr(extended, feature(generic_associated_types_extended))]
 #![cfg_attr(extended, allow(incomplete_features))]
 
diff --git a/src/test/ui/generic-associated-types/type-param-defaults.rs b/src/test/ui/generic-associated-types/type-param-defaults.rs
new file mode 100644
index 000000000000..f034076b0109
--- /dev/null
+++ b/src/test/ui/generic-associated-types/type-param-defaults.rs
@@ -0,0 +1,34 @@
+// Check that we disallow GAT param defaults, even with `invalid_type_param_default` allowed
+
+#![allow(invalid_type_param_default)]
+
+trait Trait {
+    type Assoc<T = u32>;
+    //~^ defaults for type parameters are only allowed
+}
+
+impl Trait for () {
+    type Assoc<T = u32> = u64;
+    //~^ defaults for type parameters are only allowed
+}
+
+impl Trait for u32 {
+    type Assoc<T = u32> = T;
+    //~^ defaults for type parameters are only allowed
+}
+
+trait Other {}
+impl Other for u32 {}
+
+fn foo<T>()
+where
+    T: Trait<Assoc = u32>,
+    T::Assoc: Other {
+    }
+
+fn main() {
+    // errors
+    foo::<()>();
+    // works
+    foo::<u32>();
+}
diff --git a/src/test/ui/generic-associated-types/type-param-defaults.stderr b/src/test/ui/generic-associated-types/type-param-defaults.stderr
new file mode 100644
index 000000000000..85ccaba0e69e
--- /dev/null
+++ b/src/test/ui/generic-associated-types/type-param-defaults.stderr
@@ -0,0 +1,20 @@
+error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
+  --> $DIR/type-param-defaults.rs:6:16
+   |
+LL |     type Assoc<T = u32>;
+   |                ^^^^^^^
+
+error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
+  --> $DIR/type-param-defaults.rs:11:16
+   |
+LL |     type Assoc<T = u32> = u64;
+   |                ^^^^^^^
+
+error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
+  --> $DIR/type-param-defaults.rs:16:16
+   |
+LL |     type Assoc<T = u32> = T;
+   |                ^^^^^^^
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs
index 8b40dac574a4..1cc09aa6dd4c 100644
--- a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs
+++ b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 pub trait X {
     type Y<'a: 'static>;
     //~^ WARNING unnecessary lifetime parameter
diff --git a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr
index ae52010cc50a..fbd79879d0fb 100644
--- a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr
+++ b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr
@@ -1,5 +1,5 @@
 warning: unnecessary lifetime parameter `'a`
-  --> $DIR/unsatified-item-lifetime-bound.rs:4:12
+  --> $DIR/unsatified-item-lifetime-bound.rs:2:12
    |
 LL |     type Y<'a: 'static>;
    |            ^^
@@ -7,39 +7,39 @@ LL |     type Y<'a: 'static>;
    = help: you can use the `'static` lifetime directly, in place of `'a`
 
 error[E0478]: lifetime bound not satisfied
-  --> $DIR/unsatified-item-lifetime-bound.rs:13:8
+  --> $DIR/unsatified-item-lifetime-bound.rs:11:8
    |
 LL |     f: <T as X>::Y<'a>,
    |        ^^^^^^^^^^^^^^^
    |
 note: lifetime parameter instantiated with the lifetime `'a` as defined here
-  --> $DIR/unsatified-item-lifetime-bound.rs:12:10
+  --> $DIR/unsatified-item-lifetime-bound.rs:10:10
    |
 LL | struct B<'a, T: for<'r> X<Y<'r> = &'r ()>> {
    |          ^^
    = note: but lifetime parameter must outlive the static lifetime
 
 error[E0478]: lifetime bound not satisfied
-  --> $DIR/unsatified-item-lifetime-bound.rs:18:8
+  --> $DIR/unsatified-item-lifetime-bound.rs:16:8
    |
 LL |     f: <T as X>::Y<'a>,
    |        ^^^^^^^^^^^^^^^
    |
 note: lifetime parameter instantiated with the lifetime `'a` as defined here
-  --> $DIR/unsatified-item-lifetime-bound.rs:17:10
+  --> $DIR/unsatified-item-lifetime-bound.rs:15:10
    |
 LL | struct C<'a, T: X> {
    |          ^^
    = note: but lifetime parameter must outlive the static lifetime
 
 error[E0478]: lifetime bound not satisfied
-  --> $DIR/unsatified-item-lifetime-bound.rs:23:8
+  --> $DIR/unsatified-item-lifetime-bound.rs:21:8
    |
 LL |     f: <() as X>::Y<'a>,
    |        ^^^^^^^^^^^^^^^^
    |
 note: lifetime parameter instantiated with the lifetime `'a` as defined here
-  --> $DIR/unsatified-item-lifetime-bound.rs:22:10
+  --> $DIR/unsatified-item-lifetime-bound.rs:20:10
    |
 LL | struct D<'a> {
    |          ^^
diff --git a/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.rs b/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.rs
index 6466bf98dfc8..7137d92379ef 100644
--- a/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.rs
+++ b/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait ATy {
     type Item<'a>: 'a;
 }
diff --git a/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.stderr b/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.stderr
index 7ec9386cabea..1c9ac01ec0f3 100644
--- a/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.stderr
+++ b/src/test/ui/generic-associated-types/unsatisfied-outlives-bound.stderr
@@ -1,23 +1,23 @@
 error[E0477]: the type `&'b ()` does not fulfill the required lifetime
-  --> $DIR/unsatisfied-outlives-bound.rs:8:21
+  --> $DIR/unsatisfied-outlives-bound.rs:6:21
    |
 LL |     type Item<'a> = &'b ();
    |                     ^^^^^^
    |
 note: type must outlive the lifetime `'a` as defined here as required by this binding
-  --> $DIR/unsatisfied-outlives-bound.rs:8:15
+  --> $DIR/unsatisfied-outlives-bound.rs:6:15
    |
 LL |     type Item<'a> = &'b ();
    |               ^^
 
 error[E0477]: the type `&'a ()` does not fulfill the required lifetime
-  --> $DIR/unsatisfied-outlives-bound.rs:17:21
+  --> $DIR/unsatisfied-outlives-bound.rs:15:21
    |
 LL |     type Item<'a> = &'a ();
    |                     ^^^^^^
    |
 note: type must satisfy the static lifetime as required by this binding
-  --> $DIR/unsatisfied-outlives-bound.rs:13:20
+  --> $DIR/unsatisfied-outlives-bound.rs:11:20
    |
 LL |     type Item<'a>: 'static;
    |                    ^^^^^^^
diff --git a/src/test/ui/generic-associated-types/variance_constraints.rs b/src/test/ui/generic-associated-types/variance_constraints.rs
index 7d0f7638ac89..0e9dbb8b1bec 100644
--- a/src/test/ui/generic-associated-types/variance_constraints.rs
+++ b/src/test/ui/generic-associated-types/variance_constraints.rs
@@ -1,6 +1,5 @@
 // check-pass
 // issue #69184
-#![feature(generic_associated_types)]
 
 trait A {
     type B<'a> where Self: 'a;
diff --git a/src/test/ui/generics/issue-59508-1.rs b/src/test/ui/generics/issue-59508-1.rs
index 7e1dd7707044..8e27749e8fc6 100644
--- a/src/test/ui/generics/issue-59508-1.rs
+++ b/src/test/ui/generics/issue-59508-1.rs
@@ -8,7 +8,7 @@ struct A;
 
 impl A {
     pub fn do_things<T, 'a, 'b: 'a>() {
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
         println!("panic");
     }
 }
diff --git a/src/test/ui/generics/issue-59508-1.stderr b/src/test/ui/generics/issue-59508-1.stderr
index d162365ea4bf..1c510044f806 100644
--- a/src/test/ui/generics/issue-59508-1.stderr
+++ b/src/test/ui/generics/issue-59508-1.stderr
@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/issue-59508-1.rs:10:25
    |
 LL |     pub fn do_things<T, 'a, 'b: 'a>() {
diff --git a/src/test/ui/generics/issue-59508.fixed b/src/test/ui/generics/issue-59508.fixed
index b5c60a1626f5..de8f47d4cff8 100644
--- a/src/test/ui/generics/issue-59508.fixed
+++ b/src/test/ui/generics/issue-59508.fixed
@@ -8,7 +8,7 @@ struct A;
 
 impl A {
     pub fn do_things<'a, 'b: 'a, T>() {
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
         println!("panic");
     }
 }
diff --git a/src/test/ui/generics/issue-59508.rs b/src/test/ui/generics/issue-59508.rs
index 0b39c5d8f2ae..a4c7d4ff2626 100644
--- a/src/test/ui/generics/issue-59508.rs
+++ b/src/test/ui/generics/issue-59508.rs
@@ -8,7 +8,7 @@ struct A;
 
 impl A {
     pub fn do_things<T, 'a, 'b: 'a>() {
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime parameters must be declared prior to type and const parameters
         println!("panic");
     }
 }
diff --git a/src/test/ui/generics/issue-59508.stderr b/src/test/ui/generics/issue-59508.stderr
index c52ae4182b86..fd23b6276f92 100644
--- a/src/test/ui/generics/issue-59508.stderr
+++ b/src/test/ui/generics/issue-59508.stderr
@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/issue-59508.rs:10:25
    |
 LL |     pub fn do_things<T, 'a, 'b: 'a>() {
diff --git a/src/test/ui/generics/issue-80512-param-reordering-with-defaults.rs b/src/test/ui/generics/issue-80512-param-reordering-with-defaults.rs
index fe3e4fbc7e0b..0e208818ed45 100644
--- a/src/test/ui/generics/issue-80512-param-reordering-with-defaults.rs
+++ b/src/test/ui/generics/issue-80512-param-reordering-with-defaults.rs
@@ -1,4 +1,4 @@
 #![crate_type = "lib"]
 
 struct S<T = (), 'a>(&'a T);
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
diff --git a/src/test/ui/generics/issue-80512-param-reordering-with-defaults.stderr b/src/test/ui/generics/issue-80512-param-reordering-with-defaults.stderr
index 119b1a0d2070..70793a9c9208 100644
--- a/src/test/ui/generics/issue-80512-param-reordering-with-defaults.stderr
+++ b/src/test/ui/generics/issue-80512-param-reordering-with-defaults.stderr
@@ -1,4 +1,4 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/issue-80512-param-reordering-with-defaults.rs:3:18
    |
 LL | struct S<T = (), 'a>(&'a T);
diff --git a/src/test/ui/generics/lifetime-before-type-params.rs b/src/test/ui/generics/lifetime-before-type-params.rs
index 5a71d6efeda6..d64b1b0b44f6 100644
--- a/src/test/ui/generics/lifetime-before-type-params.rs
+++ b/src/test/ui/generics/lifetime-before-type-params.rs
@@ -1,11 +1,11 @@
 #![allow(unused)]
 fn first<T, 'a, 'b>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 fn second<'a, T, 'b>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 fn third<T, U, 'a>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 fn fourth<'a, T, 'b, U, 'c, V>() {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
 
 fn main() {}
diff --git a/src/test/ui/generics/lifetime-before-type-params.stderr b/src/test/ui/generics/lifetime-before-type-params.stderr
index 62d95e45329f..84825eb4ceb2 100644
--- a/src/test/ui/generics/lifetime-before-type-params.stderr
+++ b/src/test/ui/generics/lifetime-before-type-params.stderr
@@ -1,22 +1,22 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:2:13
    |
 LL | fn first<T, 'a, 'b>() {}
    |         ----^^--^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:4:18
    |
 LL | fn second<'a, T, 'b>() {}
    |          --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:6:16
    |
 LL | fn third<T, U, 'a>() {}
    |         -------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, T, U>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/lifetime-before-type-params.rs:8:18
    |
 LL | fn fourth<'a, T, 'b, U, 'c, V>() {}
diff --git a/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr b/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr
index b4312091edb2..31e11e128351 100644
--- a/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/hrtb-just-for-static.stderr
@@ -14,6 +14,12 @@ LL | fn give_some<'a>() {
    |              -- lifetime `'a` defined here
 LL |     want_hrtb::<&'a u32>()
    |     ^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/hrtb-just-for-static.rs:9:15
+   |
+LL |     where T : for<'a> Foo<&'a isize>
+   |               ^^^^^^^^^^^^^^^^^^^^^^
 
 error: implementation of `Foo` is not general enough
   --> $DIR/hrtb-just-for-static.rs:30:5
diff --git a/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr b/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr
index 1461e7fd2ddd..5e75a4cc8afa 100644
--- a/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/hrtb-perfect-forwarding.stderr
@@ -46,6 +46,12 @@ LL | fn foo_hrtb_bar_not<'b, T>(mut t: T)
 ...
 LL |     foo_hrtb_bar_not(&mut t);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'b` must outlive `'static`
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/hrtb-perfect-forwarding.rs:37:8
+   |
+LL |     T: for<'a> Foo<&'a isize> + Bar<&'b isize>,
+   |        ^^^^^^^^^^^^^^^^^^^^^^
 
 error: implementation of `Bar` is not general enough
   --> $DIR/hrtb-perfect-forwarding.rs:43:5
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr b/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr
index ffe3d7b81f51..c1e235441d65 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr
@@ -19,7 +19,7 @@ note: the following trait bounds were not satisfied:
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
    |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here
 
-error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>`, but its trait bounds were not satisfied
+error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>`, but its trait bounds were not satisfied
   --> $DIR/issue-30786.rs:130:24
    |
 LL | pub struct Filter<S, F> {
@@ -29,12 +29,12 @@ LL | pub struct Filter<S, F> {
    | doesn't satisfy `_: StreamExt`
 ...
 LL |     let count = filter.countx();
-   |                        ^^^^^^ method cannot be called on `Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>` due to unsatisfied trait bounds
+   |                        ^^^^^^ method cannot be called on `Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>` due to unsatisfied trait bounds
    |
 note: the following trait bounds were not satisfied:
-      `&'a mut &Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>: Stream`
-      `&'a mut &mut Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>: Stream`
-      `&'a mut Filter<Map<Repeat, for<'r> fn(&'r u64) -> &'r u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>: Stream`
+      `&'a mut &Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>: Stream`
+      `&'a mut &mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>: Stream`
+      `&'a mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>: Stream`
   --> $DIR/issue-30786.rs:96:50
    |
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-46989.stderr b/src/test/ui/higher-rank-trait-bounds/issue-46989.stderr
index 309e1a676eda..3f874220a270 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-46989.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/issue-46989.stderr
@@ -4,7 +4,7 @@ error: implementation of `Foo` is not general enough
 LL |     assert_foo::<fn(&i32)>();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Foo` is not general enough
    |
-   = note: `Foo` would have to be implemented for the type `for<'r> fn(&'r i32)`
+   = note: `Foo` would have to be implemented for the type `for<'a> fn(&'a i32)`
    = note: ...but `Foo` is actually implemented for the type `fn(&'0 i32)`, for some specific lifetime `'0`
 
 error: aborting due to previous error
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-58451.stderr b/src/test/ui/higher-rank-trait-bounds/issue-58451.stderr
index 22ba63c3e86f..09e25f4dc966 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-58451.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/issue-58451.stderr
@@ -12,7 +12,7 @@ LL | fn f<I>(i: I)
 help: provide the argument
    |
 LL |     f(&[f(/* value */)]);
-   |         ~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-95034.rs b/src/test/ui/higher-rank-trait-bounds/issue-95034.rs
index d8edbe7e56b5..af4946a187f1 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-95034.rs
+++ b/src/test/ui/higher-rank-trait-bounds/issue-95034.rs
@@ -1,23 +1,5 @@
-// known-bug: #95034
-// failure-status: 101
+// check-pass
 // compile-flags: --edition=2021 --crate-type=lib
-// rustc-env:RUST_BACKTRACE=0
-
-// normalize-stderr-test "thread 'rustc' panicked.*" -> "thread 'rustc' panicked"
-// normalize-stderr-test "note:.*RUST_BACKTRACE=1.*\n" -> ""
-// normalize-stderr-test "\nerror: internal compiler error.*\n\n" -> ""
-// normalize-stderr-test "note:.*unexpectedly panicked.*\n\n" -> ""
-// normalize-stderr-test "note: we would appreciate a bug report.*\n\n" -> ""
-// normalize-stderr-test "note: compiler flags.*\n\n" -> ""
-// normalize-stderr-test "note: rustc.*running on.*\n\n" -> ""
-// normalize-stderr-test "query stack during panic:\n" -> ""
-// normalize-stderr-test "we're just showing a limited slice of the query stack\n" -> ""
-// normalize-stderr-test "end of query stack\n" -> ""
-// normalize-stderr-test "#.*\n" -> ""
-
-// This should not ICE.
-
-// Refer to the issue for more minimized versions.
 
 use std::{
     future::Future,
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-95034.stderr b/src/test/ui/higher-rank-trait-bounds/issue-95034.stderr
deleted file mode 100644
index 1d8329142fc5..000000000000
--- a/src/test/ui/higher-rank-trait-bounds/issue-95034.stderr
+++ /dev/null
@@ -1 +0,0 @@
-thread 'rustc' panicked
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-71955.stderr b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-71955.stderr
index eebce827d1ca..4ef96cd95410 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-71955.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-71955.stderr
@@ -4,8 +4,8 @@ error[E0308]: mismatched types
 LL |     foo(bar, "string", |s| s.len() == 5);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r, 's> FnOnce<(&'r &'s str,)>`
-              found trait `for<'r> FnOnce<(&'r &str,)>`
+   = note: expected trait `for<'a, 'b> FnOnce<(&'a &'b str,)>`
+              found trait `for<'a> FnOnce<(&'a &str,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-71955.rs:45:24
    |
@@ -23,8 +23,8 @@ error[E0308]: mismatched types
 LL |     foo(bar, "string", |s| s.len() == 5);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r, 's> FnOnce<(&'r &'s str,)>`
-              found trait `for<'r> FnOnce<(&'r &str,)>`
+   = note: expected trait `for<'a, 'b> FnOnce<(&'a &'b str,)>`
+              found trait `for<'a> FnOnce<(&'a &str,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-71955.rs:45:24
    |
@@ -42,8 +42,8 @@ error[E0308]: mismatched types
 LL |     foo(baz, "string", |s| s.0.len() == 5);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r, 's> FnOnce<(&'r Wrapper<'s>,)>`
-              found trait `for<'r> FnOnce<(&'r Wrapper<'_>,)>`
+   = note: expected trait `for<'a, 'b> FnOnce<(&'a Wrapper<'b>,)>`
+              found trait `for<'a> FnOnce<(&'a Wrapper<'_>,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-71955.rs:48:24
    |
@@ -61,8 +61,8 @@ error[E0308]: mismatched types
 LL |     foo(baz, "string", |s| s.0.len() == 5);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r, 's> FnOnce<(&'r Wrapper<'s>,)>`
-              found trait `for<'r> FnOnce<(&'r Wrapper<'_>,)>`
+   = note: expected trait `for<'a, 'b> FnOnce<(&'a Wrapper<'b>,)>`
+              found trait `for<'a> FnOnce<(&'a Wrapper<'_>,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-71955.rs:48:24
    |
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.rs b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.rs
index de9348f53970..c10a0888a4f2 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.rs
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.rs
@@ -6,7 +6,7 @@ trait SomeTrait<'a> {
 
 fn give_me_ice<T>() {
     callee::<fn(&()) -> <T as SomeTrait<'_>>::Associated>();
-    //~^ ERROR the trait bound `for<'r> T: SomeTrait<'r>` is not satisfied [E0277]
+    //~^ ERROR the trait bound `for<'a> T: SomeTrait<'a>` is not satisfied [E0277]
 }
 
 fn callee<T: Fn<(&'static (),)>>() {
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.stderr b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.stderr
index 6a948a116e03..25a4f6088deb 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.stderr
@@ -1,12 +1,12 @@
-error[E0277]: the trait bound `for<'r> T: SomeTrait<'r>` is not satisfied
+error[E0277]: the trait bound `for<'a> T: SomeTrait<'a>` is not satisfied
   --> $DIR/issue-85455.rs:8:5
    |
 LL |     callee::<fn(&()) -> <T as SomeTrait<'_>>::Associated>();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `for<'r> SomeTrait<'r>` is not implemented for `T`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `for<'a> SomeTrait<'a>` is not implemented for `T`
    |
 help: consider restricting type parameter `T`
    |
-LL | fn give_me_ice<T: for<'r> SomeTrait<'r>>() {
+LL | fn give_me_ice<T: for<'a> SomeTrait<'a>>() {
    |                 +++++++++++++++++++++++
 
 error: aborting due to previous error
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90612.rs b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90612.rs
index e150ecfe9a0d..effc329456d4 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90612.rs
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90612.rs
@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 use std::marker::PhantomData;
 
 trait Family: Sized {
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90638.rs b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90638.rs
index 18b7f383482a..628b5cba1042 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90638.rs
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90638.rs
@@ -1,7 +1,5 @@
 //check-pass
 
-#![feature(generic_associated_types)]
-
 trait Yokeable<'a>: 'static {
     type Output: 'a;
 }
diff --git a/src/test/ui/hygiene/impl_items.rs b/src/test/ui/hygiene/impl_items.rs
index 37794c6e0773..ddb25c06b1b1 100644
--- a/src/test/ui/hygiene/impl_items.rs
+++ b/src/test/ui/hygiene/impl_items.rs
@@ -9,7 +9,7 @@ mod foo {
     }
 
     pub macro m() {
-        let _: () = S.f(); //~ ERROR type `for<'r> fn(&'r foo::S) {foo::S::f}` is private
+        let _: () = S.f(); //~ ERROR type `for<'a> fn(&'a foo::S) {foo::S::f}` is private
     }
 }
 
diff --git a/src/test/ui/hygiene/impl_items.stderr b/src/test/ui/hygiene/impl_items.stderr
index 523309f43250..46a2500386e0 100644
--- a/src/test/ui/hygiene/impl_items.stderr
+++ b/src/test/ui/hygiene/impl_items.stderr
@@ -1,4 +1,4 @@
-error: type `for<'r> fn(&'r foo::S) {foo::S::f}` is private
+error: type `for<'a> fn(&'a foo::S) {foo::S::f}` is private
   --> $DIR/impl_items.rs:12:23
    |
 LL |         let _: () = S.f();
diff --git a/src/test/ui/impl-trait/auto-trait-leak.stderr b/src/test/ui/impl-trait/auto-trait-leak.stderr
index 634ff14869eb..b6e28364768e 100644
--- a/src/test/ui/impl-trait/auto-trait-leak.stderr
+++ b/src/test/ui/impl-trait/auto-trait-leak.stderr
@@ -29,6 +29,11 @@ note: ...which requires building MIR for `cycle1`...
    |
 LL | fn cycle1() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...which requires building THIR for `cycle1`...
+  --> $DIR/auto-trait-leak.rs:12:1
+   |
+LL | fn cycle1() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires type-checking `cycle1`...
   --> $DIR/auto-trait-leak.rs:14:5
    |
@@ -65,6 +70,11 @@ note: ...which requires building MIR for `cycle2`...
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...which requires building THIR for `cycle2`...
+  --> $DIR/auto-trait-leak.rs:19:1
+   |
+LL | fn cycle2() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires type-checking `cycle2`...
   --> $DIR/auto-trait-leak.rs:20:5
    |
diff --git a/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.edition2015.stderr b/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.edition2015.stderr
new file mode 100644
index 000000000000..edf3911e2a09
--- /dev/null
+++ b/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.edition2015.stderr
@@ -0,0 +1,9 @@
+error[E0277]: the trait bound `(): AsRef<(dyn for<'a> Fn(&'a ()) + 'static)>` is not satisfied
+  --> $DIR/generic-with-implicit-hrtb-without-dyn.rs:6:13
+   |
+LL | fn ice() -> impl AsRef<Fn(&())> {
+   |             ^^^^^^^^^^^^^^^^^^^ the trait `AsRef<(dyn for<'a> Fn(&'a ()) + 'static)>` is not implemented for `()`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.edition2021.stderr b/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.edition2021.stderr
new file mode 100644
index 000000000000..88e2520bf4b2
--- /dev/null
+++ b/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.edition2021.stderr
@@ -0,0 +1,21 @@
+error[E0782]: trait objects must include the `dyn` keyword
+  --> $DIR/generic-with-implicit-hrtb-without-dyn.rs:6:24
+   |
+LL | fn ice() -> impl AsRef<Fn(&())> {
+   |                        ^^^^^^^
+   |
+help: add `dyn` keyword before this trait
+   |
+LL | fn ice() -> impl AsRef<dyn Fn(&())> {
+   |                        +++
+
+error[E0277]: the trait bound `(): AsRef<(dyn for<'a> Fn(&'a ()) + 'static)>` is not satisfied
+  --> $DIR/generic-with-implicit-hrtb-without-dyn.rs:6:13
+   |
+LL | fn ice() -> impl AsRef<Fn(&())> {
+   |             ^^^^^^^^^^^^^^^^^^^ the trait `AsRef<(dyn for<'a> Fn(&'a ()) + 'static)>` is not implemented for `()`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0277, E0782.
+For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.rs b/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.rs
new file mode 100644
index 000000000000..5a922697f6ff
--- /dev/null
+++ b/src/test/ui/impl-trait/generic-with-implicit-hrtb-without-dyn.rs
@@ -0,0 +1,12 @@
+// revisions: edition2015 edition2021
+//[edition2021]edition:2021
+
+#![allow(warnings)]
+
+fn ice() -> impl AsRef<Fn(&())> {
+    //~^ ERROR: the trait bound `(): AsRef<(dyn for<'a> Fn(&'a ()) + 'static)>` is not satisfied [E0277]
+    //[edition2021]~| ERROR: trait objects must include the `dyn` keyword [E0782]
+    todo!()
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/in-trait/deep-match-works.rs b/src/test/ui/impl-trait/in-trait/deep-match-works.rs
new file mode 100644
index 000000000000..772da845ee1f
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/deep-match-works.rs
@@ -0,0 +1,16 @@
+// check-pass
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+struct Wrapper<T>(T);
+
+trait Foo {
+    fn bar() -> Wrapper<impl Sized>;
+}
+
+impl Foo for () {
+    fn bar() -> Wrapper<i32> { Wrapper(0) }
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/in-trait/deep-match.rs b/src/test/ui/impl-trait/in-trait/deep-match.rs
new file mode 100644
index 000000000000..a6385147c3ae
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/deep-match.rs
@@ -0,0 +1,15 @@
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+struct Wrapper<T>(T);
+
+trait Foo {
+    fn bar() -> Wrapper<impl Sized>;
+}
+
+impl Foo for () {
+    fn bar() -> i32 { 0 }
+    //~^ ERROR method `bar` has an incompatible return type for trait
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/in-trait/deep-match.stderr b/src/test/ui/impl-trait/in-trait/deep-match.stderr
new file mode 100644
index 000000000000..034ee5ea4e10
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/deep-match.stderr
@@ -0,0 +1,15 @@
+error[E0053]: method `bar` has an incompatible return type for trait
+  --> $DIR/deep-match.rs:11:17
+   |
+LL |     fn bar() -> i32 { 0 }
+   |                 ^^^
+   |                 |
+   |                 expected struct `Wrapper`, found `i32`
+   |                 return type in trait
+   |
+   = note: expected struct `Wrapper<_>`
+                found type `i32`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0053`.
diff --git a/src/test/ui/impl-trait/in-trait/doesnt-satisfy.rs b/src/test/ui/impl-trait/in-trait/doesnt-satisfy.rs
new file mode 100644
index 000000000000..bb4e0d44f3ef
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/doesnt-satisfy.rs
@@ -0,0 +1,13 @@
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+trait Foo {
+    fn bar() -> impl std::fmt::Display;
+}
+
+impl Foo for () {
+    fn bar() -> () {}
+    //~^ ERROR `()` doesn't implement `std::fmt::Display`
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/in-trait/doesnt-satisfy.stderr b/src/test/ui/impl-trait/in-trait/doesnt-satisfy.stderr
new file mode 100644
index 000000000000..aa5492d285ed
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/doesnt-satisfy.stderr
@@ -0,0 +1,17 @@
+error[E0277]: `()` doesn't implement `std::fmt::Display`
+  --> $DIR/doesnt-satisfy.rs:9:17
+   |
+LL |     fn bar() -> () {}
+   |                 ^^ `()` cannot be formatted with the default formatter
+   |
+   = help: the trait `std::fmt::Display` is not implemented for `()`
+   = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
+note: required by a bound in `Foo::bar::{opaque#0}`
+  --> $DIR/doesnt-satisfy.rs:5:22
+   |
+LL |     fn bar() -> impl std::fmt::Display;
+   |                      ^^^^^^^^^^^^^^^^^ required by this bound in `Foo::bar::{opaque#0}`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/impl-trait/in-trait/encode.rs b/src/test/ui/impl-trait/in-trait/encode.rs
new file mode 100644
index 000000000000..efb9f6498ba6
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/encode.rs
@@ -0,0 +1,9 @@
+// build-pass
+// compile-flags: --crate-type=lib
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+trait Foo {
+    fn bar() -> impl Sized;
+}
diff --git a/src/test/ui/impl-trait/in-trait/issue-102140.rs b/src/test/ui/impl-trait/in-trait/issue-102140.rs
new file mode 100644
index 000000000000..be1e012acb18
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/issue-102140.rs
@@ -0,0 +1,30 @@
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+trait Marker {}
+impl Marker for u32 {}
+
+trait MyTrait {
+    fn foo(&self) -> impl Marker
+    where
+        Self: Sized;
+}
+
+struct Outer;
+
+impl MyTrait for Outer {
+    fn foo(&self) -> impl Marker {
+        42
+    }
+}
+
+impl dyn MyTrait {
+    fn other(&self) -> impl Marker {
+        MyTrait::foo(&self)
+        //~^ ERROR the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+        //~| ERROR the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+        //~| ERROR the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/in-trait/issue-102140.stderr b/src/test/ui/impl-trait/in-trait/issue-102140.stderr
new file mode 100644
index 000000000000..08602185f50c
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/issue-102140.stderr
@@ -0,0 +1,29 @@
+error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+  --> $DIR/issue-102140.rs:23:22
+   |
+LL |         MyTrait::foo(&self)
+   |         ------------ -^^^^
+   |         |            |
+   |         |            the trait `MyTrait` is not implemented for `&dyn MyTrait`
+   |         |            help: consider removing the leading `&`-reference
+   |         required by a bound introduced by this call
+
+error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+  --> $DIR/issue-102140.rs:23:9
+   |
+LL |         MyTrait::foo(&self)
+   |         ^^^^^^^^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
+   |
+   = help: the trait `MyTrait` is implemented for `Outer`
+
+error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
+  --> $DIR/issue-102140.rs:23:9
+   |
+LL |         MyTrait::foo(&self)
+   |         ^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
+   |
+   = help: the trait `MyTrait` is implemented for `Outer`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/impl-trait/in-trait/nested-rpitit.rs b/src/test/ui/impl-trait/in-trait/nested-rpitit.rs
new file mode 100644
index 000000000000..65285e3a3cca
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/nested-rpitit.rs
@@ -0,0 +1,32 @@
+// check-pass
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+use std::fmt::Display;
+use std::ops::Deref;
+
+trait Foo {
+    fn bar(self) -> impl Deref<Target = impl Display + ?Sized>;
+}
+
+struct A;
+
+impl Foo for A {
+    fn bar(self) -> &'static str {
+        "Hello, world"
+    }
+}
+
+struct B;
+
+impl Foo for B {
+    fn bar(self) -> Box<i32> {
+        Box::new(42)
+    }
+}
+
+fn main() {
+    println!("Message for you: {:?}", &*A.bar());
+    println!("Another for you: {:?}", &*B.bar());
+}
diff --git a/src/test/ui/impl-trait/in-trait/object-safety.rs b/src/test/ui/impl-trait/in-trait/object-safety.rs
new file mode 100644
index 000000000000..dd35b9a2d8a7
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/object-safety.rs
@@ -0,0 +1,22 @@
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+use std::fmt::Debug;
+
+trait Foo {
+    fn baz(&self) -> impl Debug;
+}
+
+impl Foo for u32 {
+    fn baz(&self) -> u32 {
+        32
+    }
+}
+
+fn main() {
+    let i = Box::new(42_u32) as Box<dyn Foo>;
+    //~^ ERROR the trait `Foo` cannot be made into an object
+    //~| ERROR the trait `Foo` cannot be made into an object
+    let s = i.baz();
+    //~^ ERROR the trait `Foo` cannot be made into an object
+}
diff --git a/src/test/ui/impl-trait/in-trait/object-safety.stderr b/src/test/ui/impl-trait/in-trait/object-safety.stderr
new file mode 100644
index 000000000000..9a1554b5e1cb
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/object-safety.stderr
@@ -0,0 +1,50 @@
+error[E0038]: the trait `Foo` cannot be made into an object
+  --> $DIR/object-safety.rs:17:33
+   |
+LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
+   |                                 ^^^^^^^^^^^^ `Foo` cannot be made into an object
+   |
+note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+  --> $DIR/object-safety.rs:7:8
+   |
+LL | trait Foo {
+   |       --- this trait cannot be made into an object...
+LL |     fn baz(&self) -> impl Debug;
+   |        ^^^ ...because method `baz` references an `impl Trait` type in its return type
+   = help: consider moving `baz` to another trait
+
+error[E0038]: the trait `Foo` cannot be made into an object
+  --> $DIR/object-safety.rs:20:13
+   |
+LL |     let s = i.baz();
+   |             ^^^^^^^ `Foo` cannot be made into an object
+   |
+note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+  --> $DIR/object-safety.rs:7:8
+   |
+LL | trait Foo {
+   |       --- this trait cannot be made into an object...
+LL |     fn baz(&self) -> impl Debug;
+   |        ^^^ ...because method `baz` references an `impl Trait` type in its return type
+   = help: consider moving `baz` to another trait
+
+error[E0038]: the trait `Foo` cannot be made into an object
+  --> $DIR/object-safety.rs:17:13
+   |
+LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
+   |             ^^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
+   |
+note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+  --> $DIR/object-safety.rs:7:8
+   |
+LL | trait Foo {
+   |       --- this trait cannot be made into an object...
+LL |     fn baz(&self) -> impl Debug;
+   |        ^^^ ...because method `baz` references an `impl Trait` type in its return type
+   = help: consider moving `baz` to another trait
+   = note: required for `Box<u32>` to implement `CoerceUnsized<Box<dyn Foo>>`
+   = note: required by cast to type `Box<dyn Foo>`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0038`.
diff --git a/src/test/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs b/src/test/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
new file mode 100644
index 000000000000..3ac264e8ebac
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
@@ -0,0 +1,19 @@
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+use std::fmt::Display;
+
+trait Foo {
+    fn bar(&self) -> impl Display;
+}
+
+impl Foo for () {
+    fn bar(&self) -> impl Display {
+        "Hello, world"
+    }
+}
+
+fn main() {
+    let x: &str = ().bar();
+    //~^ ERROR mismatched types
+}
diff --git a/src/test/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr b/src/test/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr
new file mode 100644
index 000000000000..15edda483401
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr
@@ -0,0 +1,17 @@
+error[E0308]: mismatched types
+  --> $DIR/opaque-in-impl-is-opaque.rs:17:19
+   |
+LL |     fn bar(&self) -> impl Display {
+   |                      ------------ the found opaque type
+...
+LL |     let x: &str = ().bar();
+   |            ----   ^^^^^^^^ expected `&str`, found opaque type
+   |            |
+   |            expected due to this
+   |
+   = note: expected reference `&str`
+            found opaque type `impl std::fmt::Display`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/impl-trait/in-trait/opaque-in-impl.rs b/src/test/ui/impl-trait/in-trait/opaque-in-impl.rs
new file mode 100644
index 000000000000..2e06629699aa
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/opaque-in-impl.rs
@@ -0,0 +1,48 @@
+// check-pass
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+use std::fmt::Debug;
+
+trait Foo {
+    fn foo(&self) -> impl Debug;
+}
+
+impl Foo for () {
+    fn foo(&self) -> impl Debug {
+        "Hello, world"
+    }
+}
+
+impl<T: Default + Debug> Foo for std::marker::PhantomData<T> {
+    fn foo(&self) -> impl Debug {
+        T::default()
+    }
+}
+
+trait Bar {
+    fn bar<T>(&self) -> impl Debug;
+}
+
+impl Bar for () {
+    fn bar<T>(&self) -> impl Debug {
+        format!("Hello with generic {}", std::any::type_name::<T>())
+    }
+}
+
+trait Baz {
+    fn baz(&self) -> impl Debug + '_;
+}
+
+impl Baz for String {
+    fn baz(&self) -> impl Debug + '_ {
+        (self,)
+    }
+}
+
+fn main() {
+    println!("{:?}", ().foo());
+    println!("{:?}", ().bar::<u64>());
+    println!("{:?}", "hi".to_string().baz());
+}
diff --git a/src/test/ui/impl-trait/in-trait/reveal.rs b/src/test/ui/impl-trait/in-trait/reveal.rs
new file mode 100644
index 000000000000..d6ede1cc495c
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/reveal.rs
@@ -0,0 +1,18 @@
+// check-pass
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+trait Foo {
+    fn f() -> Box<impl Sized>;
+}
+
+impl Foo for () {
+    fn f() -> Box<String> {
+        Box::new(String::new())
+    }
+}
+
+fn main() {
+    let x: Box<String> = <() as Foo>::f();
+}
diff --git a/src/test/ui/impl-trait/in-trait/success.rs b/src/test/ui/impl-trait/in-trait/success.rs
new file mode 100644
index 000000000000..4cbe682b46f7
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/success.rs
@@ -0,0 +1,40 @@
+// check-pass
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+use std::fmt::Display;
+
+trait Foo {
+    fn bar(&self) -> impl Display;
+}
+
+impl Foo for i32 {
+    fn bar(&self) -> i32 {
+        *self
+    }
+}
+
+impl Foo for &'static str {
+    fn bar(&self) -> &'static str {
+        *self
+    }
+}
+
+struct Yay;
+
+impl Foo for Yay {
+    fn bar(&self) -> String {
+        String::from(":^)")
+    }
+}
+
+fn foo_generically<T: Foo>(t: T) {
+    println!("{}", t.bar());
+}
+
+fn main() {
+    println!("{}", "Hello, world.".bar());
+    println!("The answer is {}!", 42.bar());
+    foo_generically(Yay);
+}
diff --git a/src/test/ui/impl-trait/in-trait/wf-bounds.rs b/src/test/ui/impl-trait/in-trait/wf-bounds.rs
new file mode 100644
index 000000000000..2c71583b3123
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/wf-bounds.rs
@@ -0,0 +1,16 @@
+// issue #101663
+
+#![feature(return_position_impl_trait_in_trait)]
+#![allow(incomplete_features)]
+
+trait Wf<T> {}
+
+trait Uwu {
+    fn nya() -> impl Wf<Vec<[u8]>>;
+    //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time
+
+    fn nya2() -> impl Wf<[u8]>;
+    //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/in-trait/wf-bounds.stderr b/src/test/ui/impl-trait/in-trait/wf-bounds.stderr
new file mode 100644
index 000000000000..92e36841b70c
--- /dev/null
+++ b/src/test/ui/impl-trait/in-trait/wf-bounds.stderr
@@ -0,0 +1,33 @@
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/wf-bounds.rs:9:22
+   |
+LL |     fn nya() -> impl Wf<Vec<[u8]>>;
+   |                      ^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[u8]`
+note: required by a bound in `Vec`
+  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+   |
+LL | pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
+   |                ^ required by this bound in `Vec`
+
+error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+  --> $DIR/wf-bounds.rs:12:23
+   |
+LL |     fn nya2() -> impl Wf<[u8]>;
+   |                       ^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[u8]`
+note: required by a bound in `Wf`
+  --> $DIR/wf-bounds.rs:6:10
+   |
+LL | trait Wf<T> {}
+   |          ^ required by this bound in `Wf`
+help: consider relaxing the implicit `Sized` restriction
+   |
+LL | trait Wf<T: ?Sized> {}
+   |           ++++++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/impl-trait/issues/issue-78722.rs b/src/test/ui/impl-trait/issues/issue-78722.rs
index 90d1cd3798a8..9ee1ba3d3b48 100644
--- a/src/test/ui/impl-trait/issues/issue-78722.rs
+++ b/src/test/ui/impl-trait/issues/issue-78722.rs
@@ -12,7 +12,7 @@ struct Bug {
         }
         let f: F = async { 1 };
         //~^ ERROR `async` blocks are not allowed in constants
-        //~| ERROR destructors cannot be evaluated at compile-time
+        //~| ERROR destructor of
         1
     }],
 }
diff --git a/src/test/ui/impl-trait/issues/issue-78722.stderr b/src/test/ui/impl-trait/issues/issue-78722.stderr
index 9a0ffbc89d92..a96994f5a7fb 100644
--- a/src/test/ui/impl-trait/issues/issue-78722.stderr
+++ b/src/test/ui/impl-trait/issues/issue-78722.stderr
@@ -7,11 +7,11 @@ LL |         let f: F = async { 1 };
    = note: see issue #85368 <https://github.com/rust-lang/rust/issues/85368> for more information
    = help: add `#![feature(const_async_blocks)]` to the crate attributes to enable
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `F` cannot be evaluated at compile-time
   --> $DIR/issue-78722.rs:13:13
    |
 LL |         let f: F = async { 1 };
-   |             ^ constants cannot evaluate destructors
+   |             ^ the destructor for this type cannot be evaluated in constants
 ...
 LL |     }],
    |     - value is dropped here
diff --git a/src/test/ui/impl-trait/unactionable_diagnostic.fixed b/src/test/ui/impl-trait/unactionable_diagnostic.fixed
new file mode 100644
index 000000000000..6c2505177fef
--- /dev/null
+++ b/src/test/ui/impl-trait/unactionable_diagnostic.fixed
@@ -0,0 +1,25 @@
+// run-rustfix
+
+pub trait Trait {}
+
+pub struct Foo;
+
+impl Trait for Foo {}
+
+fn foo<'x, P>(
+    _post: P,
+    x: &'x Foo,
+) -> &'x impl Trait {
+    x
+}
+
+pub fn bar<'t, T: 't>(
+    //~^ HELP: consider adding an explicit lifetime bound...
+    post: T,
+    x: &'t Foo,
+) -> &'t impl Trait {
+    foo(post, x)
+    //~^ ERROR: the parameter type `T` may not live long enough
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/unactionable_diagnostic.rs b/src/test/ui/impl-trait/unactionable_diagnostic.rs
new file mode 100644
index 000000000000..bce35cbdd0d3
--- /dev/null
+++ b/src/test/ui/impl-trait/unactionable_diagnostic.rs
@@ -0,0 +1,25 @@
+// run-rustfix
+
+pub trait Trait {}
+
+pub struct Foo;
+
+impl Trait for Foo {}
+
+fn foo<'x, P>(
+    _post: P,
+    x: &'x Foo,
+) -> &'x impl Trait {
+    x
+}
+
+pub fn bar<'t, T>(
+    //~^ HELP: consider adding an explicit lifetime bound...
+    post: T,
+    x: &'t Foo,
+) -> &'t impl Trait {
+    foo(post, x)
+    //~^ ERROR: the parameter type `T` may not live long enough
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/unactionable_diagnostic.stderr b/src/test/ui/impl-trait/unactionable_diagnostic.stderr
new file mode 100644
index 000000000000..a32004cda1a6
--- /dev/null
+++ b/src/test/ui/impl-trait/unactionable_diagnostic.stderr
@@ -0,0 +1,14 @@
+error[E0309]: the parameter type `T` may not live long enough
+  --> $DIR/unactionable_diagnostic.rs:21:5
+   |
+LL |     foo(post, x)
+   |     ^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | pub fn bar<'t, T: 't>(
+   |                 ++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0309`.
diff --git a/src/test/ui/impl-trait/where-allowed.stderr b/src/test/ui/impl-trait/where-allowed.stderr
index 58a2f79efb4c..9b346387d610 100644
--- a/src/test/ui/impl-trait/where-allowed.stderr
+++ b/src/test/ui/impl-trait/where-allowed.stderr
@@ -162,12 +162,18 @@ error[E0562]: `impl Trait` only allowed in function and inherent method return t
    |
 LL |     fn in_return() -> impl Debug;
    |                       ^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `impl` method return
   --> $DIR/where-allowed.rs:125:34
    |
 LL |     fn in_trait_impl_return() -> impl Debug { () }
    |                                  ^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in `extern fn` param
   --> $DIR/where-allowed.rs:138:33
diff --git a/src/test/ui/implied-bounds/issue-101951.rs b/src/test/ui/implied-bounds/issue-101951.rs
new file mode 100644
index 000000000000..108fef8a15fb
--- /dev/null
+++ b/src/test/ui/implied-bounds/issue-101951.rs
@@ -0,0 +1,50 @@
+// Taken directly from that issue.
+//
+// This test detected that we didn't correctly resolve
+// inference variables when computing implied bounds.
+//
+// check-pass
+pub trait BuilderFn<'a> {
+    type Output;
+}
+
+impl<'a, F, Out> BuilderFn<'a> for F
+where
+    F: FnOnce(&'a mut ()) -> Out,
+{
+    type Output = Out;
+}
+
+pub trait ConstructionFirm {
+    type Builder: for<'a> BuilderFn<'a>;
+}
+
+pub trait Campus<T>
+where
+    T: ConstructionFirm,
+{
+    fn add_building(
+        &mut self,
+        building: &mut <<T as ConstructionFirm>::Builder as BuilderFn<'_>>::Output,
+    );
+}
+
+struct ArchitectsInc {}
+
+impl ConstructionFirm for ArchitectsInc {
+    type Builder = fn(&mut ()) -> PrettyCondo<'_>;
+}
+
+struct PrettyCondo<'a> {
+    _marker: &'a mut (),
+}
+
+struct CondoEstate {}
+
+impl Campus<ArchitectsInc> for CondoEstate {
+    fn add_building(&mut self, _building: &mut PrettyCondo<'_>) {
+        todo!()
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs
index bcd29bb4e349..b0c0d33975c3 100644
--- a/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Foo {
     type Output<T>;
 
diff --git a/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr
index 65a75b68c1f0..cbc2477deb39 100644
--- a/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr
+++ b/src/test/ui/inference/need_type_info/expr-struct-type-relative-gat.stderr
@@ -1,5 +1,5 @@
 error[E0282]: type annotations needed
-  --> $DIR/expr-struct-type-relative-gat.rs:17:9
+  --> $DIR/expr-struct-type-relative-gat.rs:15:9
    |
 LL |         Self::Output::Simple {};
    |         ^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the associated type `Output`
diff --git a/src/test/ui/intrinsics/const-eval-select-backtrace-std.rs b/src/test/ui/intrinsics/const-eval-select-backtrace-std.rs
new file mode 100644
index 000000000000..1164a3a5b018
--- /dev/null
+++ b/src/test/ui/intrinsics/const-eval-select-backtrace-std.rs
@@ -0,0 +1,7 @@
+// See issue #100696.
+// run-fail
+// check-run-results
+// exec-env:RUST_BACKTRACE=0
+fn main() {
+    &""[1..];
+}
diff --git a/src/test/ui/intrinsics/const-eval-select-backtrace-std.run.stderr b/src/test/ui/intrinsics/const-eval-select-backtrace-std.run.stderr
new file mode 100644
index 000000000000..463cd52c5aa7
--- /dev/null
+++ b/src/test/ui/intrinsics/const-eval-select-backtrace-std.run.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'byte index 1 is out of bounds of ``', $DIR/const-eval-select-backtrace-std.rs:6:6
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/test/ui/intrinsics/const-eval-select-backtrace.rs b/src/test/ui/intrinsics/const-eval-select-backtrace.rs
new file mode 100644
index 000000000000..ef1c7c4195b9
--- /dev/null
+++ b/src/test/ui/intrinsics/const-eval-select-backtrace.rs
@@ -0,0 +1,19 @@
+#![feature(core_intrinsics)]
+// See issue #100696.
+// run-fail
+// check-run-results
+// exec-env:RUST_BACKTRACE=0
+
+#[track_caller]
+fn uhoh() {
+    panic!("Aaah!")
+}
+
+const fn c() {}
+
+fn main() {
+    // safety: this is unsound and just used to test
+    unsafe {
+        std::intrinsics::const_eval_select((), c, uhoh);
+    }
+}
diff --git a/src/test/ui/intrinsics/const-eval-select-backtrace.run.stderr b/src/test/ui/intrinsics/const-eval-select-backtrace.run.stderr
new file mode 100644
index 000000000000..54e28db5e533
--- /dev/null
+++ b/src/test/ui/intrinsics/const-eval-select-backtrace.run.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'Aaah!', $DIR/const-eval-select-backtrace.rs:17:9
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/test/ui/intrinsics/const-eval-select-bad.rs b/src/test/ui/intrinsics/const-eval-select-bad.rs
index e5640f5ab53b..fa14efad7b4a 100644
--- a/src/test/ui/intrinsics/const-eval-select-bad.rs
+++ b/src/test/ui/intrinsics/const-eval-select-bad.rs
@@ -5,10 +5,13 @@ use std::intrinsics::const_eval_select;
 
 const fn not_fn_items() {
     const_eval_select((), || {}, || {});
-    //~^ ERROR the trait bound
+    //~^ ERROR this argument must be a function item
+    //~| ERROR this argument must be a function item
     const_eval_select((), 42, 0xDEADBEEF);
-    //~^ ERROR the trait bound
+    //~^ ERROR expected a `FnOnce<()>` closure
     //~| ERROR expected a `FnOnce<()>` closure
+    //~| ERROR this argument must be a function item
+    //~| ERROR this argument must be a function item
 }
 
 const fn foo(n: i32) -> i32 {
@@ -35,4 +38,9 @@ const fn args_ty_mismatch() {
     //~^ ERROR type mismatch
 }
 
+const fn non_const_fn() {
+    const_eval_select((1,), bar, bar);
+    //~^ ERROR this argument must be a `const fn`
+}
+
 fn main() {}
diff --git a/src/test/ui/intrinsics/const-eval-select-bad.stderr b/src/test/ui/intrinsics/const-eval-select-bad.stderr
index 1a761ad5441c..3720528ad4e4 100644
--- a/src/test/ui/intrinsics/const-eval-select-bad.stderr
+++ b/src/test/ui/intrinsics/const-eval-select-bad.stderr
@@ -1,42 +1,57 @@
-error[E0277]: the trait bound `[closure@$DIR/const-eval-select-bad.rs:7:27: 7:29]: FnOnce<()>` is not satisfied
-  --> $DIR/const-eval-select-bad.rs:7:27
-   |
-LL |     const_eval_select((), || {}, || {});
-   |     -----------------     ^^^^^ expected an `FnOnce<()>` closure, found `[closure@$DIR/const-eval-select-bad.rs:7:27: 7:29]`
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = help: the trait `~const FnOnce<()>` is not implemented for `[closure@$DIR/const-eval-select-bad.rs:7:27: 7:29]`
-note: the trait `FnOnce<()>` is implemented for `[closure@$DIR/const-eval-select-bad.rs:7:27: 7:29]`, but that implementation is not `const`
+error: this argument must be a function item
   --> $DIR/const-eval-select-bad.rs:7:27
    |
 LL |     const_eval_select((), || {}, || {});
    |                           ^^^^^
-   = note: wrap the `[closure@$DIR/const-eval-select-bad.rs:7:27: 7:29]` in a closure with no arguments: `|| { /* code */ }`
-note: required by a bound in `const_eval_select`
-  --> $SRC_DIR/core/src/intrinsics.rs:LL:COL
    |
-LL |     F: ~const FnOnce<ARG, Output = RET>,
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
+   = note: expected a function item, found [closure@$DIR/const-eval-select-bad.rs:7:27: 7:29]
+   = help: consult the documentation on `const_eval_select` for more information
 
-error[E0277]: the trait bound `{integer}: FnOnce<()>` is not satisfied
-  --> $DIR/const-eval-select-bad.rs:9:27
+error: this argument must be a function item
+  --> $DIR/const-eval-select-bad.rs:7:34
+   |
+LL |     const_eval_select((), || {}, || {});
+   |                                  ^^^^^
+   |
+   = note: expected a function item, found [closure@$DIR/const-eval-select-bad.rs:7:34: 7:36]
+   = help: consult the documentation on `const_eval_select` for more information
+
+error: this argument must be a function item
+  --> $DIR/const-eval-select-bad.rs:10:27
+   |
+LL |     const_eval_select((), 42, 0xDEADBEEF);
+   |                           ^^
+   |
+   = note: expected a function item, found {integer}
+   = help: consult the documentation on `const_eval_select` for more information
+
+error[E0277]: expected a `FnOnce<()>` closure, found `{integer}`
+  --> $DIR/const-eval-select-bad.rs:10:27
    |
 LL |     const_eval_select((), 42, 0xDEADBEEF);
    |     -----------------     ^^ expected an `FnOnce<()>` closure, found `{integer}`
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `~const FnOnce<()>` is not implemented for `{integer}`
+   = help: the trait `FnOnce<()>` is not implemented for `{integer}`
    = note: wrap the `{integer}` in a closure with no arguments: `|| { /* code */ }`
 note: required by a bound in `const_eval_select`
   --> $SRC_DIR/core/src/intrinsics.rs:LL:COL
    |
-LL |     F: ~const FnOnce<ARG, Output = RET>,
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
+LL |         F: FnOnce<ARG, Output = RET>;
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
+
+error: this argument must be a function item
+  --> $DIR/const-eval-select-bad.rs:10:31
+   |
+LL |     const_eval_select((), 42, 0xDEADBEEF);
+   |                               ^^^^^^^^^^
+   |
+   = note: expected a function item, found {integer}
+   = help: consult the documentation on `const_eval_select` for more information
 
 error[E0277]: expected a `FnOnce<()>` closure, found `{integer}`
-  --> $DIR/const-eval-select-bad.rs:9:31
+  --> $DIR/const-eval-select-bad.rs:10:31
    |
 LL |     const_eval_select((), 42, 0xDEADBEEF);
    |     -----------------         ^^^^^^^^^^ expected an `FnOnce<()>` closure, found `{integer}`
@@ -48,11 +63,11 @@ LL |     const_eval_select((), 42, 0xDEADBEEF);
 note: required by a bound in `const_eval_select`
   --> $SRC_DIR/core/src/intrinsics.rs:LL:COL
    |
-LL |     G: FnOnce<ARG, Output = RET> + ~const Destruct,
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
+LL |         G: FnOnce<ARG, Output = RET>,
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
 
 error[E0271]: expected `fn(i32) -> bool {bar}` to be a fn item that returns `i32`, but it returns `bool`
-  --> $DIR/const-eval-select-bad.rs:29:34
+  --> $DIR/const-eval-select-bad.rs:32:34
    |
 LL |     const_eval_select((1,), foo, bar);
    |     -----------------            ^^^ expected `i32`, found `bool`
@@ -62,11 +77,11 @@ LL |     const_eval_select((1,), foo, bar);
 note: required by a bound in `const_eval_select`
   --> $SRC_DIR/core/src/intrinsics.rs:LL:COL
    |
-LL |     G: FnOnce<ARG, Output = RET> + ~const Destruct,
-   |                    ^^^^^^^^^^^^ required by this bound in `const_eval_select`
+LL |         G: FnOnce<ARG, Output = RET>,
+   |                        ^^^^^^^^^^^^ required by this bound in `const_eval_select`
 
 error[E0631]: type mismatch in function arguments
-  --> $DIR/const-eval-select-bad.rs:34:32
+  --> $DIR/const-eval-select-bad.rs:37:32
    |
 LL | const fn foo(n: i32) -> i32 {
    | --------------------------- found signature defined here
@@ -81,10 +96,18 @@ LL |     const_eval_select((true,), foo, baz);
 note: required by a bound in `const_eval_select`
   --> $SRC_DIR/core/src/intrinsics.rs:LL:COL
    |
-LL |     F: ~const FnOnce<ARG, Output = RET>,
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
+LL |         F: FnOnce<ARG, Output = RET>;
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `const_eval_select`
 
-error: aborting due to 5 previous errors
+error: this argument must be a `const fn`
+  --> $DIR/const-eval-select-bad.rs:42:29
+   |
+LL |     const_eval_select((1,), bar, bar);
+   |                             ^^^
+   |
+   = help: consult the documentation on `const_eval_select` for more information
+
+error: aborting due to 9 previous errors
 
 Some errors have detailed explanations: E0271, E0277, E0631.
 For more information about an error, try `rustc --explain E0271`.
diff --git a/src/test/ui/intrinsics/panic-uninitialized-zeroed.rs b/src/test/ui/intrinsics/panic-uninitialized-zeroed.rs
index 255151a96032..4aa869cca35b 100644
--- a/src/test/ui/intrinsics/panic-uninitialized-zeroed.rs
+++ b/src/test/ui/intrinsics/panic-uninitialized-zeroed.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // revisions: mir thir strict
 // [thir]compile-flags: -Zthir-unsafeck
 // [strict]compile-flags: -Zstrict-init-checks
diff --git a/src/test/ui/invalid/invalid-inline.rs b/src/test/ui/invalid/invalid-inline.rs
index 8aa8f99f5228..2501b1e23f2f 100644
--- a/src/test/ui/invalid/invalid-inline.rs
+++ b/src/test/ui/invalid/invalid-inline.rs
@@ -1,19 +1,14 @@
 #![allow(dead_code)]
 
-#[inline(please_no)] //~ ERROR invalid argument
+#[inline(please,no)] //~ ERROR expected one argument
 fn a() {
 }
 
-#[inline(please,no)] //~ ERROR expected one argument
-fn b() {
-}
-
 #[inline()] //~ ERROR expected one argument
-fn c() {
+fn b() {
 }
 
 fn main() {
     a();
     b();
-    c();
 }
diff --git a/src/test/ui/invalid/invalid-inline.stderr b/src/test/ui/invalid/invalid-inline.stderr
index f3d042641972..7edbf936b1b4 100644
--- a/src/test/ui/invalid/invalid-inline.stderr
+++ b/src/test/ui/invalid/invalid-inline.stderr
@@ -1,22 +1,15 @@
-error[E0535]: invalid argument
-  --> $DIR/invalid-inline.rs:3:10
-   |
-LL | #[inline(please_no)]
-   |          ^^^^^^^^^
-
 error[E0534]: expected one argument
-  --> $DIR/invalid-inline.rs:7:1
+  --> $DIR/invalid-inline.rs:3:1
    |
 LL | #[inline(please,no)]
    | ^^^^^^^^^^^^^^^^^^^^
 
 error[E0534]: expected one argument
-  --> $DIR/invalid-inline.rs:11:1
+  --> $DIR/invalid-inline.rs:7:1
    |
 LL | #[inline()]
    | ^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0534, E0535.
-For more information about an error, try `rustc --explain E0534`.
+For more information about this error, try `rustc --explain E0534`.
diff --git a/src/test/ui/invalid/invalid-llvm-passes.rs b/src/test/ui/invalid/invalid-llvm-passes.rs
index ca3c6230af04..ee28f5eb6d66 100644
--- a/src/test/ui/invalid/invalid-llvm-passes.rs
+++ b/src/test/ui/invalid/invalid-llvm-passes.rs
@@ -1,4 +1,4 @@
 // build-fail
-// compile-flags: -Cpasses=unknown-pass -Z new-llvm-pass-manager=yes
+// compile-flags: -Cpasses=unknown-pass
 
 fn main() {}
diff --git a/src/test/ui/issue-94866.stderr b/src/test/ui/issue-94866.stderr
index 5477d83f4492..b3c17ce8974d 100644
--- a/src/test/ui/issue-94866.stderr
+++ b/src/test/ui/issue-94866.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `B` not covered
+error[E0004]: non-exhaustive patterns: `Enum::B` not covered
   --> $DIR/issue-94866.rs:10:11
    |
 LL |     match Enum::A {
-   |           ^^^^^^^ pattern `B` not covered
+   |           ^^^^^^^ pattern `Enum::B` not covered
    |
 note: `Enum` defined here
   --> $DIR/issue-94866.rs:7:16
@@ -13,7 +13,7 @@ LL | enum Enum { A, B }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~     Enum::A => m!(),
-LL +     B => todo!()
+LL +     Enum::B => todo!()
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/issues/issue-14875.rs b/src/test/ui/issues/issue-14875.rs
index aaef2aab9fc7..fca3309155d5 100644
--- a/src/test/ui/issues/issue-14875.rs
+++ b/src/test/ui/issues/issue-14875.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 // Check that values are not leaked when a dtor panics (#14875)
 
diff --git a/src/test/ui/issues/issue-16939.stderr b/src/test/ui/issues/issue-16939.stderr
index aaa3c49b3d83..76645645464e 100644
--- a/src/test/ui/issues/issue-16939.stderr
+++ b/src/test/ui/issues/issue-16939.stderr
@@ -12,7 +12,7 @@ LL | fn _foo<F: Fn()> (f: F) {
 help: remove the extra argument
    |
 LL |     |t| f();
-   |         ~~~
+   |          ~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-17252.stderr b/src/test/ui/issues/issue-17252.stderr
index b8f54416a085..4856418ed600 100644
--- a/src/test/ui/issues/issue-17252.stderr
+++ b/src/test/ui/issues/issue-17252.stderr
@@ -2,7 +2,7 @@ error[E0391]: cycle detected when const-evaluating + checking `FOO`
   --> $DIR/issue-17252.rs:1:1
    |
 LL | const FOO: usize = FOO;
-   | ^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: ...which immediately requires const-evaluating + checking `FOO` again
 note: cycle used when const-evaluating + checking `main::{constant#0}`
diff --git a/src/test/ui/issues/issue-18819.stderr b/src/test/ui/issues/issue-18819.stderr
index e499d0572f60..767fdd5caf06 100644
--- a/src/test/ui/issues/issue-18819.stderr
+++ b/src/test/ui/issues/issue-18819.stderr
@@ -23,7 +23,7 @@ LL |     print_x(&X);
 help: provide the argument
    |
 LL |     print_x(/* &dyn Foo<Item = bool> */, /* &str */);
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-18919.stderr b/src/test/ui/issues/issue-18919.stderr
index d7dbb8299b9e..b0b03a0eea69 100644
--- a/src/test/ui/issues/issue-18919.stderr
+++ b/src/test/ui/issues/issue-18919.stderr
@@ -1,10 +1,10 @@
-error[E0277]: the size for values of type `dyn for<'r> Fn(&'r isize) -> isize` cannot be known at compilation time
+error[E0277]: the size for values of type `dyn for<'a> Fn(&'a isize) -> isize` cannot be known at compilation time
   --> $DIR/issue-18919.rs:3:15
    |
 LL | fn ho_func(f: Option<FuncType>) {
    |               ^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
    |
-   = help: the trait `Sized` is not implemented for `dyn for<'r> Fn(&'r isize) -> isize`
+   = help: the trait `Sized` is not implemented for `dyn for<'a> Fn(&'a isize) -> isize`
 note: required by a bound in `Option`
   --> $DIR/issue-18919.rs:7:13
    |
diff --git a/src/test/ui/issues/issue-21174.stderr b/src/test/ui/issues/issue-21174.stderr
index 09402c3d8141..5981d9dc7330 100644
--- a/src/test/ui/issues/issue-21174.stderr
+++ b/src/test/ui/issues/issue-21174.stderr
@@ -4,8 +4,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
 LL |     let new: T::B = unsafe { std::mem::transmute(value) };
    |                              ^^^^^^^^^^^^^^^^^^^
    |
-   = note: source type: `<T as Trait>::A` (this type does not have a fixed size)
-   = note: target type: `<T as Trait>::B` (this type does not have a fixed size)
+   = note: source type: `<T as Trait<'_>>::A` (this type does not have a fixed size)
+   = note: target type: `<T as Trait<'_>>::B` (this type does not have a fixed size)
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-23302-3.stderr b/src/test/ui/issues/issue-23302-3.stderr
index e9314207537c..074939f68a88 100644
--- a/src/test/ui/issues/issue-23302-3.stderr
+++ b/src/test/ui/issues/issue-23302-3.stderr
@@ -2,13 +2,13 @@ error[E0391]: cycle detected when const-evaluating + checking `A`
   --> $DIR/issue-23302-3.rs:1:1
    |
 LL | const A: i32 = B;
-   | ^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^
    |
 note: ...which requires const-evaluating + checking `B`...
   --> $DIR/issue-23302-3.rs:3:1
    |
 LL | const B: i32 = A;
-   | ^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^
    = note: ...which again requires const-evaluating + checking `A`, completing the cycle
 note: cycle used when simplifying constant for the type system `A`
   --> $DIR/issue-23302-3.rs:1:1
diff --git a/src/test/ui/issues/issue-23611-enum-swap-in-drop.rs b/src/test/ui/issues/issue-23611-enum-swap-in-drop.rs
index 403cf970bcb0..cdb130d600c5 100644
--- a/src/test/ui/issues/issue-23611-enum-swap-in-drop.rs
+++ b/src/test/ui/issues/issue-23611-enum-swap-in-drop.rs
@@ -97,7 +97,7 @@ pub fn main() {
     // ever hands f_A off to instances of GaspA, and thus one should
     // be able to prove the invariant that f_A is *only* invoked from
     // from an instance of GaspA (either via the GaspA drop
-    // implementation or the E drop implementaton). Yet the old (bad)
+    // implementation or the E drop implementation). Yet the old (bad)
     // behavior allowed a call to f_A to leak in while we are tearing
     // down a value of type GaspB.
 }
diff --git a/src/test/ui/issues/issue-24322.stderr b/src/test/ui/issues/issue-24322.stderr
index 1a4fab165405..1e4c8ac7c356 100644
--- a/src/test/ui/issues/issue-24322.stderr
+++ b/src/test/ui/issues/issue-24322.stderr
@@ -6,8 +6,8 @@ LL |     let x: &fn(&B) -> u32 = &B::func;
    |            |
    |            expected due to this
    |
-   = note: expected reference `&for<'r> fn(&'r B) -> u32`
-              found reference `&for<'r> fn(&'r B) -> u32 {B::func}`
+   = note: expected reference `&for<'a> fn(&'a B) -> u32`
+              found reference `&for<'a> fn(&'a B) -> u32 {B::func}`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-25901.rs b/src/test/ui/issues/issue-25901.rs
index ba12e1ad0211..1f7b341a97ef 100644
--- a/src/test/ui/issues/issue-25901.rs
+++ b/src/test/ui/issues/issue-25901.rs
@@ -2,7 +2,7 @@ struct A;
 struct B;
 
 static S: &'static B = &A;
-//~^ ERROR cannot perform deref coercion on `A` in statics
+//~^ ERROR the trait bound
 
 use std::ops::Deref;
 
diff --git a/src/test/ui/issues/issue-25901.stderr b/src/test/ui/issues/issue-25901.stderr
index c6c80e41cf67..b9cac32229a1 100644
--- a/src/test/ui/issues/issue-25901.stderr
+++ b/src/test/ui/issues/issue-25901.stderr
@@ -1,23 +1,15 @@
-error[E0015]: cannot perform deref coercion on `A` in statics
+error[E0277]: the trait bound `A: Deref` is not satisfied
+  --> $DIR/issue-25901.rs:4:24
+   |
+LL | static S: &'static B = &A;
+   |                        ^^ the trait `~const Deref` is not implemented for `A`
+   |
+note: the trait `Deref` is implemented for `A`, but that implementation is not `const`
   --> $DIR/issue-25901.rs:4:24
    |
 LL | static S: &'static B = &A;
    |                        ^^
-   |
-   = note: attempting to deref into `B`
-note: deref defined here
-  --> $DIR/issue-25901.rs:10:5
-   |
-LL |     type Target = B;
-   |     ^^^^^^^^^^^
-note: impl defined here, but it is not `const`
-  --> $DIR/issue-25901.rs:9:1
-   |
-LL | impl Deref for A {
-   | ^^^^^^^^^^^^^^^^
-   = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/issues/issue-26217.stderr b/src/test/ui/issues/issue-26217.stderr
index c7601caacdca..73c772205c3d 100644
--- a/src/test/ui/issues/issue-26217.stderr
+++ b/src/test/ui/issues/issue-26217.stderr
@@ -5,6 +5,12 @@ LL | fn bar<'a>() {
    |        -- lifetime `'a` defined here
 LL |     foo::<&'a i32>();
    |     ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/issue-26217.rs:1:30
+   |
+LL | fn foo<T>() where for<'a> T: 'a {}
+   |                              ^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-29948.rs b/src/test/ui/issues/issue-29948.rs
index 01c3ec64861f..3ed701480b5e 100644
--- a/src/test/ui/issues/issue-29948.rs
+++ b/src/test/ui/issues/issue-29948.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 use std::panic;
 
diff --git a/src/test/ui/issues/issue-40000.stderr b/src/test/ui/issues/issue-40000.stderr
index e6f0b5fbfba1..c41fbb9d2ec1 100644
--- a/src/test/ui/issues/issue-40000.stderr
+++ b/src/test/ui/issues/issue-40000.stderr
@@ -4,7 +4,7 @@ error[E0308]: mismatched types
 LL |     foo(bar);
    |         ^^^ one type is more general than the other
    |
-   = note: expected trait object `dyn for<'r> Fn(&'r i32)`
+   = note: expected trait object `dyn for<'a> Fn(&'a i32)`
               found trait object `dyn Fn(&i32)`
 
 error[E0308]: mismatched types
@@ -13,7 +13,7 @@ error[E0308]: mismatched types
 LL |     foo(bar);
    |         ^^^ one type is more general than the other
    |
-   = note: expected trait object `dyn for<'r> Fn(&'r i32)`
+   = note: expected trait object `dyn for<'a> Fn(&'a i32)`
               found trait object `dyn Fn(&i32)`
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/issues/issue-41139.stderr b/src/test/ui/issues/issue-41139.stderr
index 48b22bca20f0..97492e6e0fa2 100644
--- a/src/test/ui/issues/issue-41139.stderr
+++ b/src/test/ui/issues/issue-41139.stderr
@@ -5,9 +5,7 @@ LL | fn get_function<'a>() -> &'a dyn Fn() -> dyn Trait {
    | -------------------------------------------------- `get_function` defined here returns `&dyn Fn() -> (dyn Trait + 'static)`
 ...
 LL |     let t: &dyn Trait = &get_function()();
-   |                          ^^^^^^^^^^^^^^--
-   |                          |
-   |                          call expression requires function
+   |                          ^^^^^^^^^^^^^^ this trait object returns an unsized value `(dyn Trait + 'static)`, so it cannot be called
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-43853.rs b/src/test/ui/issues/issue-43853.rs
index 3162c091c878..dd42c1e3cb83 100644
--- a/src/test/ui/issues/issue-43853.rs
+++ b/src/test/ui/issues/issue-43853.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 use std::panic;
 
diff --git a/src/test/ui/issues/issue-43988.stderr b/src/test/ui/issues/issue-43988.stderr
index 03aa37f52075..02c5dd5bfb77 100644
--- a/src/test/ui/issues/issue-43988.stderr
+++ b/src/test/ui/issues/issue-43988.stderr
@@ -31,12 +31,16 @@ error[E0552]: unrecognized representation hint
    |
 LL |     #[repr(nothing)]
    |            ^^^^^^^
+   |
+   = help: valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
 
 error[E0552]: unrecognized representation hint
   --> $DIR/issue-43988.rs:18:12
    |
 LL |     #[repr(something_not_real)]
    |            ^^^^^^^^^^^^^^^^^^
+   |
+   = help: valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
 
 error[E0518]: attribute should be applied to function or closure
   --> $DIR/issue-43988.rs:30:5
diff --git a/src/test/ui/issues/issue-46519.rs b/src/test/ui/issues/issue-46519.rs
index 9bd3c0948517..0567923b7fc6 100644
--- a/src/test/ui/issues/issue-46519.rs
+++ b/src/test/ui/issues/issue-46519.rs
@@ -2,7 +2,6 @@
 // compile-flags:--test -O
 
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #[test]
 #[should_panic(expected = "creating inhabited type")]
diff --git a/src/test/ui/issues/issue-47511.stderr b/src/test/ui/issues/issue-47511.stderr
index 5b84f7ed62c3..9998ee0e8d0c 100644
--- a/src/test/ui/issues/issue-47511.stderr
+++ b/src/test/ui/issues/issue-47511.stderr
@@ -4,7 +4,8 @@ error[E0581]: return type references an anonymous lifetime, which is not constra
 LL | fn f(_: X) -> X {
    |               ^
    |
-   = note: lifetimes appearing in an associated type are not considered constrained
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
 
 error[E0581]: return type references lifetime `'a`, which is not constrained by the fn input types
   --> $DIR/issue-47511.rs:12:23
diff --git a/src/test/ui/issues/issue-4935.stderr b/src/test/ui/issues/issue-4935.stderr
index aab19a699ace..bb45fa083381 100644
--- a/src/test/ui/issues/issue-4935.stderr
+++ b/src/test/ui/issues/issue-4935.stderr
@@ -12,7 +12,7 @@ LL | fn foo(a: usize) {}
 help: remove the extra argument
    |
 LL | fn main() { foo(5) }
-   |             ~~~~~~
+   |                ~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-50582.stderr b/src/test/ui/issues/issue-50582.stderr
index 3d527eb6b4e4..53ecc6112ffe 100644
--- a/src/test/ui/issues/issue-50582.stderr
+++ b/src/test/ui/issues/issue-50582.stderr
@@ -7,13 +7,13 @@ LL |     Vec::<[(); 1 + for x in 0..1 {}]>::new();
    = note: see issue #87575 <https://github.com/rust-lang/rust/issues/87575> for more information
    = help: add `#![feature(const_for)]` to the crate attributes to enable
 
-error[E0277]: cannot add `()` to `{integer}`
+error[E0277]: cannot add `()` to `{integer}` in const contexts
   --> $DIR/issue-50582.rs:2:18
    |
 LL |     Vec::<[(); 1 + for x in 0..1 {}]>::new();
    |                  ^ no implementation for `{integer} + ()`
    |
-   = help: the trait `Add<()>` is not implemented for `{integer}`
+   = help: the trait `~const Add<()>` is not implemented for `{integer}`
    = help: the following other types implement trait `Add<Rhs>`:
              <&'a f32 as Add<f32>>
              <&'a f64 as Add<f64>>
diff --git a/src/test/ui/issues/issue-57362-2.stderr b/src/test/ui/issues/issue-57362-2.stderr
index 3b6cffeafe4c..7d08c4643ff2 100644
--- a/src/test/ui/issues/issue-57362-2.stderr
+++ b/src/test/ui/issues/issue-57362-2.stderr
@@ -1,11 +1,11 @@
-error[E0599]: the function or associated item `make_g` exists for fn pointer `for<'r> fn(&'r ())`, but its trait bounds were not satisfied
+error[E0599]: the function or associated item `make_g` exists for fn pointer `for<'a> fn(&'a ())`, but its trait bounds were not satisfied
   --> $DIR/issue-57362-2.rs:22:25
    |
 LL |     let x = <fn (&())>::make_g();
-   |                         ^^^^^^ function or associated item cannot be called on `for<'r> fn(&'r ())` due to unsatisfied trait bounds
+   |                         ^^^^^^ function or associated item cannot be called on `for<'a> fn(&'a ())` due to unsatisfied trait bounds
    |
    = note: the following trait bounds were not satisfied:
-           `for<'r> fn(&'r ()): X`
+           `for<'a> fn(&'a ()): X`
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `X` defines an item `make_g`, perhaps you need to implement it
   --> $DIR/issue-57362-2.rs:8:1
diff --git a/src/test/ui/issues/issue-59488.stderr b/src/test/ui/issues/issue-59488.stderr
index e5368ddf1e57..08fe0b35eb7d 100644
--- a/src/test/ui/issues/issue-59488.stderr
+++ b/src/test/ui/issues/issue-59488.stderr
@@ -89,7 +89,7 @@ error[E0277]: `fn(usize) -> Foo {Foo::Bar}` doesn't implement `Debug`
 LL |     assert_eq!(Foo::Bar, i);
    |     ^^^^^^^^^^^^^^^^^^^^^^^ `fn(usize) -> Foo {Foo::Bar}` cannot be formatted using `{:?}` because it doesn't implement `Debug`
    |
-   = help: the trait `Debug` is not implemented for `fn(usize) -> Foo {Foo::Bar}`
+   = help: the trait `Debug` is not implemented for fn item `fn(usize) -> Foo {Foo::Bar}`
    = help: the following other types implement trait `Debug`:
              extern "C" fn() -> Ret
              extern "C" fn(A, B) -> Ret
@@ -108,7 +108,7 @@ error[E0277]: `fn(usize) -> Foo {Foo::Bar}` doesn't implement `Debug`
 LL |     assert_eq!(Foo::Bar, i);
    |     ^^^^^^^^^^^^^^^^^^^^^^^ `fn(usize) -> Foo {Foo::Bar}` cannot be formatted using `{:?}` because it doesn't implement `Debug`
    |
-   = help: the trait `Debug` is not implemented for `fn(usize) -> Foo {Foo::Bar}`
+   = help: the trait `Debug` is not implemented for fn item `fn(usize) -> Foo {Foo::Bar}`
    = help: the following other types implement trait `Debug`:
              extern "C" fn() -> Ret
              extern "C" fn(A, B) -> Ret
diff --git a/src/test/ui/issues/issue-66706.rs b/src/test/ui/issues/issue-66706.rs
index 4585bcc8cd57..835fdfae86c0 100644
--- a/src/test/ui/issues/issue-66706.rs
+++ b/src/test/ui/issues/issue-66706.rs
@@ -2,7 +2,6 @@ fn a() {
     [0; [|_: _ &_| ()].len()]
     //~^ ERROR expected `,`, found `&`
     //~| ERROR type annotations needed
-    //~| ERROR mismatched types
 }
 
 fn b() {
@@ -13,13 +12,11 @@ fn b() {
 fn c() {
     [0; [|&_: _ &_| {}; 0 ].len()]
     //~^ ERROR expected `,`, found `&`
-    //~| ERROR mismatched types
 }
 
 fn d() {
     [0; match [|f @ &ref _| () ] {} ]
     //~^ ERROR expected identifier, found reserved identifier `_`
-    //~| ERROR mismatched types
 }
 
 fn main() {}
diff --git a/src/test/ui/issues/issue-66706.stderr b/src/test/ui/issues/issue-66706.stderr
index 1c55560cb7c7..8a30c0cad39c 100644
--- a/src/test/ui/issues/issue-66706.stderr
+++ b/src/test/ui/issues/issue-66706.stderr
@@ -7,13 +7,13 @@ LL |     [0; [|_: _ &_| ()].len()]
    |               help: missing `,`
 
 error: expected identifier, found reserved identifier `_`
-  --> $DIR/issue-66706.rs:9:20
+  --> $DIR/issue-66706.rs:8:20
    |
 LL |     [0; [|f @ &ref _| {} ; 0 ].len() ];
    |                    ^ expected identifier, found reserved identifier
 
 error: expected `,`, found `&`
-  --> $DIR/issue-66706.rs:14:17
+  --> $DIR/issue-66706.rs:13:17
    |
 LL |     [0; [|&_: _ &_| {}; 0 ].len()]
    |                -^ expected `,`
@@ -21,7 +21,7 @@ LL |     [0; [|&_: _ &_| {}; 0 ].len()]
    |                help: missing `,`
 
 error: expected identifier, found reserved identifier `_`
-  --> $DIR/issue-66706.rs:20:26
+  --> $DIR/issue-66706.rs:18:26
    |
 LL |     [0; match [|f @ &ref _| () ] {} ]
    |                          ^ expected identifier, found reserved identifier
@@ -32,31 +32,6 @@ error[E0282]: type annotations needed
 LL |     [0; [|_: _ &_| ()].len()]
    |           ^ cannot infer type
 
-error[E0308]: mismatched types
-  --> $DIR/issue-66706.rs:2:5
-   |
-LL | fn a() {
-   |        - help: try adding a return type: `-> [i32; _]`
-LL |     [0; [|_: _ &_| ()].len()]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
+error: aborting due to 5 previous errors
 
-error[E0308]: mismatched types
-  --> $DIR/issue-66706.rs:14:5
-   |
-LL | fn c() {
-   |        - help: try adding a return type: `-> [i32; _]`
-LL |     [0; [|&_: _ &_| {}; 0 ].len()]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
-
-error[E0308]: mismatched types
-  --> $DIR/issue-66706.rs:20:5
-   |
-LL | fn d() {
-   |        - help: try adding a return type: `-> [i32; _]`
-LL |     [0; match [|f @ &ref _| () ] {} ]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
-
-error: aborting due to 8 previous errors
-
-Some errors have detailed explanations: E0282, E0308.
-For more information about an error, try `rustc --explain E0282`.
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/issues/issue-70724-add_type_neq_err_label-unwrap.stderr b/src/test/ui/issues/issue-70724-add_type_neq_err_label-unwrap.stderr
index 9239385e6436..7f29709ce509 100644
--- a/src/test/ui/issues/issue-70724-add_type_neq_err_label-unwrap.stderr
+++ b/src/test/ui/issues/issue-70724-add_type_neq_err_label-unwrap.stderr
@@ -28,7 +28,7 @@ LL | fn a() -> i32 {
 LL |     assert_eq!(a, 0);
    |     ^^^^^^^^^^^^^^^^ `fn() -> i32 {a}` cannot be formatted using `{:?}` because it doesn't implement `Debug`
    |
-   = help: the trait `Debug` is not implemented for `fn() -> i32 {a}`
+   = help: the trait `Debug` is not implemented for fn item `fn() -> i32 {a}`
    = help: use parentheses to call the function: `a()`
    = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
diff --git a/src/test/ui/issues/issue-86756.stderr b/src/test/ui/issues/issue-86756.stderr
index 399c940ca195..b26c1834d84a 100644
--- a/src/test/ui/issues/issue-86756.stderr
+++ b/src/test/ui/issues/issue-86756.stderr
@@ -25,9 +25,8 @@ LL |     eq::<dyn, Foo>
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     eq::<dyn, Foo>
-LL +     eq::<dyn, dyn Foo>
-   |
+LL |     eq::<dyn, dyn Foo>
+   |               +++
 
 error[E0107]: missing generics for trait `Foo`
   --> $DIR/issue-86756.rs:5:15
diff --git a/src/test/ui/issues/issue-87707.rs b/src/test/ui/issues/issue-87707.rs
index 26e9e2c8f91c..c14e52dfe4cf 100644
--- a/src/test/ui/issues/issue-87707.rs
+++ b/src/test/ui/issues/issue-87707.rs
@@ -3,6 +3,7 @@
 // run-fail
 // exec-env:RUST_BACKTRACE=0
 // check-run-results
+// needs-unwind uses catch_unwind
 
 use std::sync::Once;
 use std::panic;
diff --git a/src/test/ui/issues/issue-87707.run.stderr b/src/test/ui/issues/issue-87707.run.stderr
index e6c9ea0eb53c..527c78ba89e9 100644
--- a/src/test/ui/issues/issue-87707.run.stderr
+++ b/src/test/ui/issues/issue-87707.run.stderr
@@ -1,3 +1,3 @@
-thread 'main' panicked at 'Here Once instance is poisoned.', $DIR/issue-87707.rs:13:24
+thread 'main' panicked at 'Here Once instance is poisoned.', $DIR/issue-87707.rs:14:24
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'Once instance has previously been poisoned', $DIR/issue-87707.rs:15:7
+thread 'main' panicked at 'Once instance has previously been poisoned', $DIR/issue-87707.rs:16:7
diff --git a/src/test/ui/issues/issue-99875.rs b/src/test/ui/issues/issue-99875.rs
new file mode 100644
index 000000000000..cf73fd8d31fb
--- /dev/null
+++ b/src/test/ui/issues/issue-99875.rs
@@ -0,0 +1,16 @@
+struct Argument;
+struct Return;
+
+fn function(_: Argument) -> Return { todo!() }
+
+trait Trait {}
+impl Trait for fn(Argument) -> Return {}
+
+fn takes(_: impl Trait) {}
+
+fn main() {
+    takes(function);
+    //~^ ERROR the trait bound
+    takes(|_: Argument| -> Return { todo!() });
+    //~^ ERROR the trait bound
+}
diff --git a/src/test/ui/issues/issue-99875.stderr b/src/test/ui/issues/issue-99875.stderr
new file mode 100644
index 000000000000..3ff8f12f1b8c
--- /dev/null
+++ b/src/test/ui/issues/issue-99875.stderr
@@ -0,0 +1,33 @@
+error[E0277]: the trait bound `fn(Argument) -> Return {function}: Trait` is not satisfied
+  --> $DIR/issue-99875.rs:12:11
+   |
+LL |     takes(function);
+   |     ----- ^^^^^^^^ the trait `Trait` is not implemented for fn item `fn(Argument) -> Return {function}`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `Trait` is implemented for fn pointer `fn(Argument) -> Return`
+note: required by a bound in `takes`
+  --> $DIR/issue-99875.rs:9:18
+   |
+LL | fn takes(_: impl Trait) {}
+   |                  ^^^^^ required by this bound in `takes`
+
+error[E0277]: the trait bound `[closure@$DIR/issue-99875.rs:14:11: 14:34]: Trait` is not satisfied
+  --> $DIR/issue-99875.rs:14:11
+   |
+LL |     takes(|_: Argument| -> Return { todo!() });
+   |     ----- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for closure `[closure@$DIR/issue-99875.rs:14:11: 14:34]`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `Trait` is implemented for fn pointer `fn(Argument) -> Return`
+note: required by a bound in `takes`
+  --> $DIR/issue-99875.rs:9:18
+   |
+LL | fn takes(_: impl Trait) {}
+   |                  ^^^^^ required by this bound in `takes`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/iterators/issue-28098.rs b/src/test/ui/iterators/issue-28098.rs
index c4addaccefc1..80c77edae9eb 100644
--- a/src/test/ui/iterators/issue-28098.rs
+++ b/src/test/ui/iterators/issue-28098.rs
@@ -1,12 +1,15 @@
 fn main() {
     let _ = Iterator::next(&mut ());
     //~^ ERROR `()` is not an iterator
+    //~| ERROR `()` is not an iterator
+    //~| ERROR `()` is not an iterator
 
     for _ in false {}
     //~^ ERROR `bool` is not an iterator
 
     let _ = Iterator::next(&mut ());
     //~^ ERROR `()` is not an iterator
+    //~| ERROR `()` is not an iterator
 
     other()
 }
@@ -16,9 +19,12 @@ pub fn other() {
 
     let _ = Iterator::next(&mut ());
     //~^ ERROR `()` is not an iterator
+    //~| ERROR `()` is not an iterator
+    //~| ERROR `()` is not an iterator
 
     let _ = Iterator::next(&mut ());
     //~^ ERROR `()` is not an iterator
+    //~| ERROR `()` is not an iterator
 
     for _ in false {}
     //~^ ERROR `bool` is not an iterator
diff --git a/src/test/ui/iterators/issue-28098.stderr b/src/test/ui/iterators/issue-28098.stderr
index 53b610c17239..3256e57d4361 100644
--- a/src/test/ui/iterators/issue-28098.stderr
+++ b/src/test/ui/iterators/issue-28098.stderr
@@ -8,8 +8,16 @@ LL |     let _ = Iterator::next(&mut ());
    |
    = help: the trait `Iterator` is not implemented for `()`
 
+error[E0277]: `()` is not an iterator
+  --> $DIR/issue-28098.rs:2:13
+   |
+LL |     let _ = Iterator::next(&mut ());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ `()` is not an iterator
+   |
+   = help: the trait `Iterator` is not implemented for `()`
+
 error[E0277]: `bool` is not an iterator
-  --> $DIR/issue-28098.rs:5:14
+  --> $DIR/issue-28098.rs:7:14
    |
 LL |     for _ in false {}
    |              ^^^^^ `bool` is not an iterator
@@ -18,7 +26,7 @@ LL |     for _ in false {}
    = note: required for `bool` to implement `IntoIterator`
 
 error[E0277]: `()` is not an iterator
-  --> $DIR/issue-28098.rs:8:28
+  --> $DIR/issue-28098.rs:10:28
    |
 LL |     let _ = Iterator::next(&mut ());
    |             -------------- ^^^^^^^ `()` is not an iterator
@@ -28,12 +36,18 @@ LL |     let _ = Iterator::next(&mut ());
    = help: the trait `Iterator` is not implemented for `()`
 
 error[E0277]: `()` is not an iterator
-  --> $DIR/issue-28098.rs:17:28
+  --> $DIR/issue-28098.rs:10:13
    |
 LL |     let _ = Iterator::next(&mut ());
-   |             -------------- ^^^^^^^ `()` is not an iterator
-   |             |
-   |             required by a bound introduced by this call
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ `()` is not an iterator
+   |
+   = help: the trait `Iterator` is not implemented for `()`
+
+error[E0277]: `()` is not an iterator
+  --> $DIR/issue-28098.rs:2:13
+   |
+LL |     let _ = Iterator::next(&mut ());
+   |             ^^^^^^^^^^^^^^ `()` is not an iterator
    |
    = help: the trait `Iterator` is not implemented for `()`
 
@@ -47,8 +61,34 @@ LL |     let _ = Iterator::next(&mut ());
    |
    = help: the trait `Iterator` is not implemented for `()`
 
+error[E0277]: `()` is not an iterator
+  --> $DIR/issue-28098.rs:20:13
+   |
+LL |     let _ = Iterator::next(&mut ());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ `()` is not an iterator
+   |
+   = help: the trait `Iterator` is not implemented for `()`
+
+error[E0277]: `()` is not an iterator
+  --> $DIR/issue-28098.rs:25:28
+   |
+LL |     let _ = Iterator::next(&mut ());
+   |             -------------- ^^^^^^^ `()` is not an iterator
+   |             |
+   |             required by a bound introduced by this call
+   |
+   = help: the trait `Iterator` is not implemented for `()`
+
+error[E0277]: `()` is not an iterator
+  --> $DIR/issue-28098.rs:25:13
+   |
+LL |     let _ = Iterator::next(&mut ());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ `()` is not an iterator
+   |
+   = help: the trait `Iterator` is not implemented for `()`
+
 error[E0277]: `bool` is not an iterator
-  --> $DIR/issue-28098.rs:23:14
+  --> $DIR/issue-28098.rs:29:14
    |
 LL |     for _ in false {}
    |              ^^^^^ `bool` is not an iterator
@@ -56,6 +96,14 @@ LL |     for _ in false {}
    = help: the trait `Iterator` is not implemented for `bool`
    = note: required for `bool` to implement `IntoIterator`
 
-error: aborting due to 6 previous errors
+error[E0277]: `()` is not an iterator
+  --> $DIR/issue-28098.rs:20:13
+   |
+LL |     let _ = Iterator::next(&mut ());
+   |             ^^^^^^^^^^^^^^ `()` is not an iterator
+   |
+   = help: the trait `Iterator` is not implemented for `()`
+
+error: aborting due to 12 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/iterators/issue-58952-filter-type-length.rs b/src/test/ui/iterators/issue-58952-filter-type-length.rs
index ffbe89a14e3b..6d12db8d1373 100644
--- a/src/test/ui/iterators/issue-58952-filter-type-length.rs
+++ b/src/test/ui/iterators/issue-58952-filter-type-length.rs
@@ -1,6 +1,6 @@
 // run-pass
 //! This snippet causes the type length to blowup exponentially,
-//! so check that we don't accidentially exceed the type length limit.
+//! so check that we don't accidentally exceed the type length limit.
 // FIXME: Once the size of iterator adaptors is further reduced,
 // increase the complexity of this test.
 use std::collections::VecDeque;
diff --git a/src/test/ui/iterators/iter-count-overflow-debug.rs b/src/test/ui/iterators/iter-count-overflow-debug.rs
index 15f25f1ca537..8e59c11e9dcc 100644
--- a/src/test/ui/iterators/iter-count-overflow-debug.rs
+++ b/src/test/ui/iterators/iter-count-overflow-debug.rs
@@ -1,7 +1,6 @@
 // run-pass
 // only-32bit too impatient for 2⁶⁴ items
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes -C opt-level=3
 
 use std::panic;
diff --git a/src/test/ui/iterators/iter-position-overflow-debug.rs b/src/test/ui/iterators/iter-position-overflow-debug.rs
index 65124c282412..7a871e744c98 100644
--- a/src/test/ui/iterators/iter-position-overflow-debug.rs
+++ b/src/test/ui/iterators/iter-position-overflow-debug.rs
@@ -1,7 +1,6 @@
 // run-pass
 // only-32bit too impatient for 2⁶⁴ items
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes -C opt-level=3
 
 use std::panic;
diff --git a/src/test/ui/iterators/iter-step-overflow-debug.rs b/src/test/ui/iterators/iter-step-overflow-debug.rs
index e16f984de79a..6aa349ebed29 100644
--- a/src/test/ui/iterators/iter-step-overflow-debug.rs
+++ b/src/test/ui/iterators/iter-step-overflow-debug.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes
 
 use std::panic;
diff --git a/src/test/ui/iterators/iter-sum-overflow-debug.rs b/src/test/ui/iterators/iter-sum-overflow-debug.rs
index d8ce43848a77..24c764ff9587 100644
--- a/src/test/ui/iterators/iter-sum-overflow-debug.rs
+++ b/src/test/ui/iterators/iter-sum-overflow-debug.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -C debug_assertions=yes
 
 use std::panic;
diff --git a/src/test/ui/iterators/iter-sum-overflow-overflow-checks.rs b/src/test/ui/iterators/iter-sum-overflow-overflow-checks.rs
index bc8dcbdbb0e0..be45c075d733 100644
--- a/src/test/ui/iterators/iter-sum-overflow-overflow-checks.rs
+++ b/src/test/ui/iterators/iter-sum-overflow-overflow-checks.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: -C overflow-checks
 
 use std::panic;
diff --git a/src/test/ui/layout/issue-96158-scalarpair-payload-might-be-uninit.stderr b/src/test/ui/layout/issue-96158-scalarpair-payload-might-be-uninit.stderr
index 6deb1f271a72..bfabe2d12f7f 100644
--- a/src/test/ui/layout/issue-96158-scalarpair-payload-might-be-uninit.stderr
+++ b/src/test/ui/layout/issue-96158-scalarpair-payload-might-be-uninit.stderr
@@ -411,7 +411,7 @@ error: layout_of(NicheFirst) = Layout {
                    valid_range: 0..=4,
                },
                tag_encoding: Niche {
-                   dataful_variant: 0,
+                   untagged_variant: 0,
                    niche_variants: 1..=2,
                    niche_start: 3,
                },
@@ -555,7 +555,7 @@ error: layout_of(NicheSecond) = Layout {
                    valid_range: 0..=4,
                },
                tag_encoding: Niche {
-                   dataful_variant: 0,
+                   untagged_variant: 0,
                    niche_variants: 1..=2,
                    niche_start: 3,
                },
diff --git a/src/test/ui/layout/zero-sized-array-enum-niche.stderr b/src/test/ui/layout/zero-sized-array-enum-niche.stderr
index 56d3a52bb7ff..a3e82070e0f5 100644
--- a/src/test/ui/layout/zero-sized-array-enum-niche.stderr
+++ b/src/test/ui/layout/zero-sized-array-enum-niche.stderr
@@ -353,7 +353,7 @@ error: layout_of(std::result::Result<[u32; 0], Packed<U16IsZero>>) = Layout {
                    valid_range: 0..=1,
                },
                tag_encoding: Niche {
-                   dataful_variant: 1,
+                   untagged_variant: 1,
                    niche_variants: 0..=0,
                    niche_start: 1,
                },
diff --git a/src/test/ui/let-else/const-fn.rs b/src/test/ui/let-else/const-fn.rs
new file mode 100644
index 000000000000..a3921b8033fc
--- /dev/null
+++ b/src/test/ui/let-else/const-fn.rs
@@ -0,0 +1,18 @@
+// run-pass
+// issue #101932
+
+
+const fn foo(a: Option<i32>) -> i32 {
+    let Some(a) = a else {
+        return 42
+    };
+
+    a + 1
+}
+
+fn main() {
+    const A: i32 = foo(None);
+    const B: i32 = foo(Some(1));
+
+    println!("{} {}", A, B);
+}
diff --git a/src/test/ui/let-else/issue-100103.rs b/src/test/ui/let-else/issue-100103.rs
index e393deab764f..f5f9b2f5f063 100644
--- a/src/test/ui/let-else/issue-100103.rs
+++ b/src/test/ui/let-else/issue-100103.rs
@@ -2,7 +2,7 @@
 // check-pass
 
 #![feature(try_blocks)]
-#![feature(let_else)]
+
 
 fn main() {
     let _: Result<i32, i32> = try {
diff --git a/src/test/ui/let-else/issue-94176.rs b/src/test/ui/let-else/issue-94176.rs
index e35bbd888306..f76dfc15bc15 100644
--- a/src/test/ui/let-else/issue-94176.rs
+++ b/src/test/ui/let-else/issue-94176.rs
@@ -1,6 +1,6 @@
 // Issue #94176: wrong span for the error message of a mismatched type error,
 // if the function uses a `let else` construct.
-#![feature(let_else)]
+
 
 pub fn test(a: Option<u32>) -> Option<u32> { //~ ERROR mismatched types
     let Some(_) = a else { return None; };
diff --git a/src/test/ui/let-else/issue-99975.rs b/src/test/ui/let-else/issue-99975.rs
new file mode 100644
index 000000000000..5b164f347e7d
--- /dev/null
+++ b/src/test/ui/let-else/issue-99975.rs
@@ -0,0 +1,20 @@
+// run-pass
+// compile-flags: -C opt-level=3 -Zvalidate-mir
+
+
+
+fn return_result() -> Option<String> {
+    Some("ok".to_string())
+}
+
+fn start() -> String {
+    let Some(content) = return_result() else {
+        return "none".to_string()
+    };
+
+    content
+}
+
+fn main() {
+    start();
+}
diff --git a/src/test/ui/let-else/let-else-allow-in-expr.rs b/src/test/ui/let-else/let-else-allow-in-expr.rs
index 39f4c9060fea..33acb6c6a29c 100644
--- a/src/test/ui/let-else/let-else-allow-in-expr.rs
+++ b/src/test/ui/let-else/let-else-allow-in-expr.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 #![deny(unused_variables)]
 
 fn main() {
diff --git a/src/test/ui/let-else/let-else-allow-in-expr.stderr b/src/test/ui/let-else/let-else-allow-in-expr.stderr
index e86bcbc85002..3b2b9066c90d 100644
--- a/src/test/ui/let-else/let-else-allow-in-expr.stderr
+++ b/src/test/ui/let-else/let-else-allow-in-expr.stderr
@@ -1,17 +1,17 @@
 error: unused variable: `x`
-  --> $DIR/let-else-allow-in-expr.rs:7:13
+  --> $DIR/let-else-allow-in-expr.rs:5:13
    |
 LL |         let x = 1;
    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
    |
 note: the lint level is defined here
-  --> $DIR/let-else-allow-in-expr.rs:3:9
+  --> $DIR/let-else-allow-in-expr.rs:1:9
    |
 LL | #![deny(unused_variables)]
    |         ^^^^^^^^^^^^^^^^
 
 error: unused variable: `x`
-  --> $DIR/let-else-allow-in-expr.rs:29:9
+  --> $DIR/let-else-allow-in-expr.rs:27:9
    |
 LL |     let x = 1;
    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
diff --git a/src/test/ui/let-else/let-else-allow-unused.rs b/src/test/ui/let-else/let-else-allow-unused.rs
index 86ebacfa7b7d..bbb1c7beaf8d 100644
--- a/src/test/ui/let-else/let-else-allow-unused.rs
+++ b/src/test/ui/let-else/let-else-allow-unused.rs
@@ -1,6 +1,6 @@
 // issue #89807
 
-#![feature(let_else)]
+
 
 #[deny(unused_variables)]
 
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs b/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs
index b65fa13c1de1..955f33ee134d 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 // Verify the binding mode shifts - only when no `&` are auto-dereferenced is the
 // final default binding mode mutable.
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs b/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs
index 63b35df76aa0..1524d0102333 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs
@@ -1,8 +1,8 @@
-#![feature(let_else)]
-
 // Slightly different from explicit-mut-annotated -- this won't show an error until borrowck.
 // Should it show a type error instead?
 
+
+
 fn main() {
     let Some(n): &mut Option<i32> = &mut &Some(5i32) else {
         //~^ ERROR cannot borrow data in a `&` reference as mutable
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs b/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs
index 305be9221921..b0a6264a10d4 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_else)]
+
 
 fn main() {
     let Some(n) = &mut &mut Some(5i32) else { return; };
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut.rs b/src/test/ui/let-else/let-else-binding-explicit-mut.rs
index dbe4715b1a97..a153b3af0de1 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 // Verify the binding mode shifts - only when no `&` are auto-dereferenced is the
 // final default binding mode mutable.
diff --git a/src/test/ui/let-else/let-else-binding-immutable.rs b/src/test/ui/let-else/let-else-binding-immutable.rs
index 96de0ffe26e6..ff2d9f240a09 100644
--- a/src/test/ui/let-else/let-else-binding-immutable.rs
+++ b/src/test/ui/let-else/let-else-binding-immutable.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 pub fn main() {
     let Some(x) = &Some(3) else {
diff --git a/src/test/ui/let-else/let-else-bindings.rs b/src/test/ui/let-else/let-else-bindings.rs
index d5121e744dad..7d2cad978fc0 100644
--- a/src/test/ui/let-else/let-else-bindings.rs
+++ b/src/test/ui/let-else/let-else-bindings.rs
@@ -1,6 +1,6 @@
 // run-pass
 // adapted from src/test/ui/binding/if-let.rs
-#![feature(let_else)]
+
 #![allow(dead_code)]
 
 fn none() -> bool {
diff --git a/src/test/ui/let-else/let-else-bool-binop-init.fixed b/src/test/ui/let-else/let-else-bool-binop-init.fixed
index e47f7f23d7e0..20e558ca909c 100644
--- a/src/test/ui/let-else/let-else-bool-binop-init.fixed
+++ b/src/test/ui/let-else/let-else-bool-binop-init.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let true = (true && false) else { return }; //~ ERROR a `&&` expression cannot be directly assigned in `let...else`
diff --git a/src/test/ui/let-else/let-else-bool-binop-init.rs b/src/test/ui/let-else/let-else-bool-binop-init.rs
index e443fb0d6a37..f88179a940b5 100644
--- a/src/test/ui/let-else/let-else-bool-binop-init.rs
+++ b/src/test/ui/let-else/let-else-bool-binop-init.rs
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let true = true && false else { return }; //~ ERROR a `&&` expression cannot be directly assigned in `let...else`
diff --git a/src/test/ui/let-else/let-else-brace-before-else.fixed b/src/test/ui/let-else/let-else-brace-before-else.fixed
index fb4fd77791e0..a75c770ddf29 100644
--- a/src/test/ui/let-else/let-else-brace-before-else.fixed
+++ b/src/test/ui/let-else/let-else-brace-before-else.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let Some(1) = ({ Some(1) }) else {
diff --git a/src/test/ui/let-else/let-else-brace-before-else.rs b/src/test/ui/let-else/let-else-brace-before-else.rs
index c4c5a1ca28bb..5603b946f388 100644
--- a/src/test/ui/let-else/let-else-brace-before-else.rs
+++ b/src/test/ui/let-else/let-else-brace-before-else.rs
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let Some(1) = { Some(1) } else {
diff --git a/src/test/ui/let-else/let-else-check.rs b/src/test/ui/let-else/let-else-check.rs
index 9e32cbef742a..713fd986e979 100644
--- a/src/test/ui/let-else/let-else-check.rs
+++ b/src/test/ui/let-else/let-else-check.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 #![deny(unused_variables)]
 
 fn main() {
diff --git a/src/test/ui/let-else/let-else-check.stderr b/src/test/ui/let-else/let-else-check.stderr
index 3d647a4c05d8..bdecbf708f9d 100644
--- a/src/test/ui/let-else/let-else-check.stderr
+++ b/src/test/ui/let-else/let-else-check.stderr
@@ -1,17 +1,17 @@
 error: unused variable: `x`
-  --> $DIR/let-else-check.rs:14:13
+  --> $DIR/let-else-check.rs:12:13
    |
 LL |         let x = 1;
    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
    |
 note: the lint level is defined here
-  --> $DIR/let-else-check.rs:3:9
+  --> $DIR/let-else-check.rs:1:9
    |
 LL | #![deny(unused_variables)]
    |         ^^^^^^^^^^^^^^^^
 
 error: unused variable: `x`
-  --> $DIR/let-else-check.rs:18:9
+  --> $DIR/let-else-check.rs:16:9
    |
 LL |     let x = 1;
    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
diff --git a/src/test/ui/let-else/let-else-deref-coercion-annotated.rs b/src/test/ui/let-else/let-else-deref-coercion-annotated.rs
index 65d88a6d8282..60fdf825a336 100644
--- a/src/test/ui/let-else/let-else-deref-coercion-annotated.rs
+++ b/src/test/ui/let-else/let-else-deref-coercion-annotated.rs
@@ -6,7 +6,7 @@
 // Deref/DerefMut to Bar. You can do this with an irrefutable binding, so it should work with
 // let-else too.
 
-#![feature(let_else)]
+
 use std::ops::{Deref, DerefMut};
 
 struct Foo(Bar);
diff --git a/src/test/ui/let-else/let-else-deref-coercion.rs b/src/test/ui/let-else/let-else-deref-coercion.rs
index 87489d84bbf3..052a5a8c73cc 100644
--- a/src/test/ui/let-else/let-else-deref-coercion.rs
+++ b/src/test/ui/let-else/let-else-deref-coercion.rs
@@ -3,7 +3,7 @@
 // We attempt to `let Bar::Present(_) = foo else { ... }` where foo is meant to Deref/DerefMut to
 // Bar. This fails, you must add a type annotation like `let _: &mut Bar = _ else { ... }`
 
-#![feature(let_else)]
+
 use std::ops::{Deref, DerefMut};
 
 struct Foo(Bar);
diff --git a/src/test/ui/let-else/let-else-destructuring.rs b/src/test/ui/let-else/let-else-destructuring.rs
index 9a09c414ac80..d1f1a69bfc25 100644
--- a/src/test/ui/let-else/let-else-destructuring.rs
+++ b/src/test/ui/let-else/let-else-destructuring.rs
@@ -1,4 +1,3 @@
-#![feature(let_else)]
 #[derive(Debug)]
 enum Foo {
     Done,
diff --git a/src/test/ui/let-else/let-else-destructuring.stderr b/src/test/ui/let-else/let-else-destructuring.stderr
index 95efb7116829..7d6cb2386440 100644
--- a/src/test/ui/let-else/let-else-destructuring.stderr
+++ b/src/test/ui/let-else/let-else-destructuring.stderr
@@ -1,11 +1,11 @@
 error: <assignment> ... else { ... } is not allowed
-  --> $DIR/let-else-destructuring.rs:11:9
+  --> $DIR/let-else-destructuring.rs:10:9
    |
 LL |         &Foo::Nested(Some(value)) = value else { break };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0070]: invalid left-hand side of assignment
-  --> $DIR/let-else-destructuring.rs:11:35
+  --> $DIR/let-else-destructuring.rs:10:35
    |
 LL |         &Foo::Nested(Some(value)) = value else { break };
    |         ------------------------- ^
diff --git a/src/test/ui/let-else/let-else-drop-order.rs b/src/test/ui/let-else/let-else-drop-order.rs
new file mode 100644
index 000000000000..e91e5de84e4b
--- /dev/null
+++ b/src/test/ui/let-else/let-else-drop-order.rs
@@ -0,0 +1,270 @@
+// run-pass
+// edition:2021
+// check-run-results
+//
+// Drop order tests for let else
+//
+// Mostly this ensures two things:
+// 1. That let and let else temporary drop order is the same.
+//    This is a specific design request: https://github.com/rust-lang/rust/pull/93628#issuecomment-1047140316
+// 2. That the else block truly only runs after the
+//    temporaries have dropped.
+//
+// We also print some nice tables for an overview by humans.
+// Changes in those tables are considered breakages, but the
+// important properties 1 and 2 are also enforced by the code.
+// This is important as it's easy to update the stdout file
+// with a --bless and miss the impact of that change.
+
+
+#![allow(irrefutable_let_patterns)]
+
+use std::cell::RefCell;
+use std::rc::Rc;
+
+#[derive(Clone)]
+struct DropAccountant(Rc<RefCell<Vec<Vec<String>>>>);
+
+impl DropAccountant {
+    fn new() -> Self {
+        Self(Default::default())
+    }
+    fn build_droppy(&self, v: u32) -> Droppy<u32> {
+        Droppy(self.clone(), v)
+    }
+    fn build_droppy_enum_none(&self, _v: u32) -> ((), DroppyEnum<u32>) {
+        ((), DroppyEnum::None(self.clone()))
+    }
+    fn new_list(&self, s: impl ToString) {
+        self.0.borrow_mut().push(vec![s.to_string()]);
+    }
+    fn push(&self, s: impl ToString) {
+        let s = s.to_string();
+        let mut accounts = self.0.borrow_mut();
+        accounts.last_mut().unwrap().push(s);
+    }
+    fn print_table(&self) {
+        println!();
+
+        let accounts = self.0.borrow();
+        let before_last = &accounts[accounts.len() - 2];
+        let last = &accounts[accounts.len() - 1];
+        let before_last = get_comma_list(before_last);
+        let last = get_comma_list(last);
+        const LINES: &[&str] = &[
+            "vanilla",
+            "&",
+            "&mut",
+            "move",
+            "fn(this)",
+            "tuple",
+            "array",
+            "ref &",
+            "ref mut &mut",
+        ];
+        let max_len = LINES.iter().map(|v| v.len()).max().unwrap();
+        let max_len_before = before_last.iter().map(|v| v.len()).max().unwrap();
+        let max_len_last = last.iter().map(|v| v.len()).max().unwrap();
+
+        println!(
+            "| {: <max_len$} | {: <max_len_before$} | {: <max_len_last$} |",
+            "construct", before_last[0], last[0]
+        );
+        println!("| {:-<max_len$} | {:-<max_len_before$} | {:-<max_len_last$} |", "", "", "");
+
+        for ((l, l_before), l_last) in
+            LINES.iter().zip(before_last[1..].iter()).zip(last[1..].iter())
+        {
+            println!(
+                "| {: <max_len$} | {: <max_len_before$} | {: <max_len_last$} |",
+                l, l_before, l_last,
+            );
+        }
+    }
+    #[track_caller]
+    fn assert_all_equal_to(&self, st: &str) {
+        let accounts = self.0.borrow();
+        let last = &accounts[accounts.len() - 1];
+        let last = get_comma_list(last);
+        for line in last[1..].iter() {
+            assert_eq!(line.trim(), st.trim());
+        }
+    }
+    #[track_caller]
+    fn assert_equality_last_two_lists(&self) {
+        let accounts = self.0.borrow();
+        let last = &accounts[accounts.len() - 1];
+        let before_last = &accounts[accounts.len() - 2];
+        for (l, b) in last[1..].iter().zip(before_last[1..].iter()) {
+            if !(l == b || l == "n/a" || b == "n/a") {
+                panic!("not equal: '{last:?}' != '{before_last:?}'");
+            }
+        }
+    }
+}
+
+fn get_comma_list(sl: &[String]) -> Vec<String> {
+    std::iter::once(sl[0].clone())
+        .chain(sl[1..].chunks(2).map(|c| c.join(",")))
+        .collect::<Vec<String>>()
+}
+
+struct Droppy<T>(DropAccountant, T);
+
+impl<T> Drop for Droppy<T> {
+    fn drop(&mut self) {
+        self.0.push("drop");
+    }
+}
+
+#[allow(dead_code)]
+enum DroppyEnum<T> {
+    Some(DropAccountant, T),
+    None(DropAccountant),
+}
+
+impl<T> Drop for DroppyEnum<T> {
+    fn drop(&mut self) {
+        match self {
+            DroppyEnum::Some(acc, _inner) => acc,
+            DroppyEnum::None(acc) => acc,
+        }
+        .push("drop");
+    }
+}
+
+macro_rules! nestings_with {
+    ($construct:ident, $binding:pat, $exp:expr) => {
+        // vanilla:
+        $construct!($binding, $exp.1);
+
+        // &:
+        $construct!(&$binding, &$exp.1);
+
+        // &mut:
+        $construct!(&mut $binding, &mut ($exp.1));
+
+        {
+            // move:
+            let w = $exp;
+            $construct!(
+                $binding,
+                {
+                    let w = w;
+                    w
+                }
+                .1
+            );
+        }
+
+        // fn(this):
+        $construct!($binding, std::convert::identity($exp).1);
+    };
+}
+
+macro_rules! nestings {
+    ($construct:ident, $binding:pat, $exp:expr) => {
+        nestings_with!($construct, $binding, $exp);
+
+        // tuple:
+        $construct!(($binding, 77), ($exp.1, 77));
+
+        // array:
+        $construct!([$binding], [$exp.1]);
+    };
+}
+
+macro_rules! let_else {
+    ($acc:expr, $v:expr, $binding:pat, $build:ident) => {
+        let acc = $acc;
+        let v = $v;
+
+        macro_rules! let_else_construct {
+            ($arg:pat, $exp:expr) => {
+                loop {
+                    let $arg = $exp else {
+                        acc.push("else");
+                        break;
+                    };
+                    acc.push("body");
+                    break;
+                }
+            };
+        }
+        nestings!(let_else_construct, $binding, acc.$build(v));
+        // ref &:
+        let_else_construct!($binding, &acc.$build(v).1);
+
+        // ref mut &mut:
+        let_else_construct!($binding, &mut acc.$build(v).1);
+    };
+}
+
+macro_rules! let_ {
+    ($acc:expr, $binding:tt) => {
+        let acc = $acc;
+
+        macro_rules! let_construct {
+            ($arg:pat, $exp:expr) => {{
+                let $arg = $exp;
+                acc.push("body");
+            }};
+        }
+        let v = 0;
+        {
+            nestings_with!(let_construct, $binding, acc.build_droppy(v));
+        }
+        acc.push("n/a");
+        acc.push("n/a");
+        acc.push("n/a");
+        acc.push("n/a");
+
+        // ref &:
+        let_construct!($binding, &acc.build_droppy(v).1);
+
+        // ref mut &mut:
+        let_construct!($binding, &mut acc.build_droppy(v).1);
+    };
+}
+
+fn main() {
+    let acc = DropAccountant::new();
+
+    println!(" --- matching cases ---");
+
+    // Ensure that let and let else have the same behaviour
+    acc.new_list("let _");
+    let_!(&acc, _);
+    acc.new_list("let else _");
+    let_else!(&acc, 0, _, build_droppy);
+    acc.assert_equality_last_two_lists();
+    acc.print_table();
+
+    // Ensure that let and let else have the same behaviour
+    acc.new_list("let _v");
+    let_!(&acc, _v);
+    acc.new_list("let else _v");
+    let_else!(&acc, 0, _v, build_droppy);
+    acc.assert_equality_last_two_lists();
+    acc.print_table();
+
+    println!();
+
+    println!(" --- mismatching cases ---");
+
+    acc.new_list("let else _ mismatch");
+    let_else!(&acc, 1, DroppyEnum::Some(_, _), build_droppy_enum_none);
+    acc.new_list("let else _v mismatch");
+    let_else!(&acc, 1, DroppyEnum::Some(_, _v), build_droppy_enum_none);
+    acc.print_table();
+    // This ensures that we always drop before visiting the else case
+    acc.assert_all_equal_to("drop,else");
+
+    acc.new_list("let else 0 mismatch");
+    let_else!(&acc, 1, 0, build_droppy);
+    acc.new_list("let else 0 mismatch");
+    let_else!(&acc, 1, 0, build_droppy);
+    acc.print_table();
+    // This ensures that we always drop before visiting the else case
+    acc.assert_all_equal_to("drop,else");
+}
diff --git a/src/test/ui/let-else/let-else-drop-order.run.stdout b/src/test/ui/let-else/let-else-drop-order.run.stdout
new file mode 100644
index 000000000000..01cf2f73e17c
--- /dev/null
+++ b/src/test/ui/let-else/let-else-drop-order.run.stdout
@@ -0,0 +1,51 @@
+ --- matching cases ---
+
+| construct    | let _     | let else _ |
+| ------------ | --------- | ---------- |
+| vanilla      | drop,body | drop,body  |
+| &            | body,drop | body,drop  |
+| &mut         | body,drop | body,drop  |
+| move         | drop,body | drop,body  |
+| fn(this)     | drop,body | drop,body  |
+| tuple        | n/a,n/a   | drop,body  |
+| array        | n/a,n/a   | drop,body  |
+| ref &        | body,drop | body,drop  |
+| ref mut &mut | body,drop | body,drop  |
+
+| construct    | let _v    | let else _v |
+| ------------ | --------- | ----------- |
+| vanilla      | drop,body | drop,body   |
+| &            | body,drop | body,drop   |
+| &mut         | body,drop | body,drop   |
+| move         | drop,body | drop,body   |
+| fn(this)     | drop,body | drop,body   |
+| tuple        | n/a,n/a   | drop,body   |
+| array        | n/a,n/a   | drop,body   |
+| ref &        | body,drop | body,drop   |
+| ref mut &mut | body,drop | body,drop   |
+
+ --- mismatching cases ---
+
+| construct    | let else _ mismatch | let else _v mismatch |
+| ------------ | ------------------- | -------------------- |
+| vanilla      | drop,else           | drop,else            |
+| &            | drop,else           | drop,else            |
+| &mut         | drop,else           | drop,else            |
+| move         | drop,else           | drop,else            |
+| fn(this)     | drop,else           | drop,else            |
+| tuple        | drop,else           | drop,else            |
+| array        | drop,else           | drop,else            |
+| ref &        | drop,else           | drop,else            |
+| ref mut &mut | drop,else           | drop,else            |
+
+| construct    | let else 0 mismatch | let else 0 mismatch |
+| ------------ | ------------------- | ------------------- |
+| vanilla      | drop,else           | drop,else           |
+| &            | drop,else           | drop,else           |
+| &mut         | drop,else           | drop,else           |
+| move         | drop,else           | drop,else           |
+| fn(this)     | drop,else           | drop,else           |
+| tuple        | drop,else           | drop,else           |
+| array        | drop,else           | drop,else           |
+| ref &        | drop,else           | drop,else           |
+| ref mut &mut | drop,else           | drop,else           |
diff --git a/src/test/ui/let-else/let-else-if.rs b/src/test/ui/let-else/let-else-if.rs
index c3a17330d6e2..e8c54ca7ab29 100644
--- a/src/test/ui/let-else/let-else-if.rs
+++ b/src/test/ui/let-else/let-else-if.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(_) = Some(()) else if true {
         //~^ ERROR conditional `else if` is not supported for `let...else`
diff --git a/src/test/ui/let-else/let-else-if.stderr b/src/test/ui/let-else/let-else-if.stderr
index 746738bbd939..c63fd61c5dec 100644
--- a/src/test/ui/let-else/let-else-if.stderr
+++ b/src/test/ui/let-else/let-else-if.stderr
@@ -1,5 +1,5 @@
 error: conditional `else if` is not supported for `let...else`
-  --> $DIR/let-else-if.rs:4:33
+  --> $DIR/let-else-if.rs:2:33
    |
 LL |     let Some(_) = Some(()) else if true {
    |                                 ^^ expected `{`
diff --git a/src/test/ui/let-else/let-else-irrefutable.rs b/src/test/ui/let-else/let-else-irrefutable.rs
index b1e09a1248ff..1cb68ecb8a6b 100644
--- a/src/test/ui/let-else/let-else-irrefutable.rs
+++ b/src/test/ui/let-else/let-else-irrefutable.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_else)]
+
 
 fn main() {
     let x = 1 else { return }; //~ WARN irrefutable `let...else` pattern
diff --git a/src/test/ui/let-else/let-else-missing-semicolon.rs b/src/test/ui/let-else/let-else-missing-semicolon.rs
index ed9d79f1ebde..d87ac90c1a77 100644
--- a/src/test/ui/let-else/let-else-missing-semicolon.rs
+++ b/src/test/ui/let-else/let-else-missing-semicolon.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(x) = Some(1) else {
         return;
diff --git a/src/test/ui/let-else/let-else-missing-semicolon.stderr b/src/test/ui/let-else/let-else-missing-semicolon.stderr
index 1818a0b12634..99029ff33fe0 100644
--- a/src/test/ui/let-else/let-else-missing-semicolon.stderr
+++ b/src/test/ui/let-else/let-else-missing-semicolon.stderr
@@ -1,5 +1,5 @@
 error: expected `;`, found keyword `let`
-  --> $DIR/let-else-missing-semicolon.rs:6:6
+  --> $DIR/let-else-missing-semicolon.rs:4:6
    |
 LL |     }
    |      ^ help: add `;` here
@@ -7,7 +7,7 @@ LL |     let _ = "";
    |     --- unexpected token
 
 error: expected `;`, found `}`
-  --> $DIR/let-else-missing-semicolon.rs:10:6
+  --> $DIR/let-else-missing-semicolon.rs:8:6
    |
 LL |     }
    |      ^ help: add `;` here
diff --git a/src/test/ui/let-else/let-else-no-double-error.rs b/src/test/ui/let-else/let-else-no-double-error.rs
index 35dcdd3f6be3..91fcc5d7e91e 100644
--- a/src/test/ui/let-else/let-else-no-double-error.rs
+++ b/src/test/ui/let-else/let-else-no-double-error.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 // Without caching type lookups in FnCtxt.resolve_ty_and_def_ufcs
 // the error below would be reported twice (once when checking
diff --git a/src/test/ui/let-else/let-else-non-copy.rs b/src/test/ui/let-else/let-else-non-copy.rs
index 79ed82dd124b..08c07dd1a43a 100644
--- a/src/test/ui/let-else/let-else-non-copy.rs
+++ b/src/test/ui/let-else/let-else-non-copy.rs
@@ -10,7 +10,7 @@
 //
 // The move was due to mir::Place being Copy, but mir::VarDebugInfoContents not being Copy.
 
-#![feature(let_else)]
+
 
 #[derive(Copy, Clone)]
 struct Copyable;
diff --git a/src/test/ui/let-else/let-else-non-diverging.rs b/src/test/ui/let-else/let-else-non-diverging.rs
index a1cee335aeeb..b5bd91ceb9e7 100644
--- a/src/test/ui/let-else/let-else-non-diverging.rs
+++ b/src/test/ui/let-else/let-else-non-diverging.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(x) = Some(1) else { //~ ERROR does not diverge
         Some(2)
diff --git a/src/test/ui/let-else/let-else-non-diverging.stderr b/src/test/ui/let-else/let-else-non-diverging.stderr
index 05e45f689890..c999a5495256 100644
--- a/src/test/ui/let-else/let-else-non-diverging.stderr
+++ b/src/test/ui/let-else/let-else-non-diverging.stderr
@@ -1,5 +1,5 @@
 error[E0308]: `else` clause of `let...else` does not diverge
-  --> $DIR/let-else-non-diverging.rs:4:32
+  --> $DIR/let-else-non-diverging.rs:2:32
    |
 LL |       let Some(x) = Some(1) else {
    |  ________________________________^
@@ -13,7 +13,7 @@ LL | |     };
    = help: ...or use `match` instead of `let...else`
 
 error[E0308]: `else` clause of `let...else` does not diverge
-  --> $DIR/let-else-non-diverging.rs:7:32
+  --> $DIR/let-else-non-diverging.rs:5:32
    |
 LL |       let Some(x) = Some(1) else {
    |  ________________________________^
@@ -29,7 +29,7 @@ LL | |     };
    = help: ...or use `match` instead of `let...else`
 
 error[E0308]: `else` clause of `let...else` does not diverge
-  --> $DIR/let-else-non-diverging.rs:12:32
+  --> $DIR/let-else-non-diverging.rs:10:32
    |
 LL |     let Some(x) = Some(1) else { Some(2) };
    |                                ^^^^^^^^^^^ expected `!`, found enum `Option`
diff --git a/src/test/ui/let-else/let-else-ref-bindings-pass.rs b/src/test/ui/let-else/let-else-ref-bindings-pass.rs
index f4abd6cc2df2..62fc65731cd2 100644
--- a/src/test/ui/let-else/let-else-ref-bindings-pass.rs
+++ b/src/test/ui/let-else/let-else-ref-bindings-pass.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_else)]
+
 #![allow(unused_variables)]
 
 fn ref_() {
diff --git a/src/test/ui/let-else/let-else-ref-bindings.rs b/src/test/ui/let-else/let-else-ref-bindings.rs
index a4cd8e8c47d4..687e235d47e7 100644
--- a/src/test/ui/let-else/let-else-ref-bindings.rs
+++ b/src/test/ui/let-else/let-else-ref-bindings.rs
@@ -1,6 +1,6 @@
-#![feature(let_else)]
 #![allow(unused_variables)]
 
+
 fn ref_() {
     let bytes: Vec<u8> = b"Hello"[..].to_vec();
     let some = Some(bytes);
diff --git a/src/test/ui/let-else/let-else-run-pass.rs b/src/test/ui/let-else/let-else-run-pass.rs
index 5d96623236da..a0fb6c683f8c 100644
--- a/src/test/ui/let-else/let-else-run-pass.rs
+++ b/src/test/ui/let-else/let-else-run-pass.rs
@@ -1,6 +1,6 @@
 // run-pass
 
-#![feature(let_else)]
+
 
 fn main() {
     #[allow(dead_code)]
diff --git a/src/test/ui/let-else/let-else-scope.rs b/src/test/ui/let-else/let-else-scope.rs
index f17682db4c3b..78a67769ef28 100644
--- a/src/test/ui/let-else/let-else-scope.rs
+++ b/src/test/ui/let-else/let-else-scope.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(x) = Some(2) else {
         panic!("{}", x); //~ ERROR cannot find value `x` in this scope
diff --git a/src/test/ui/let-else/let-else-scope.stderr b/src/test/ui/let-else/let-else-scope.stderr
index 4b3936eac4bd..3b4f0982940e 100644
--- a/src/test/ui/let-else/let-else-scope.stderr
+++ b/src/test/ui/let-else/let-else-scope.stderr
@@ -1,5 +1,5 @@
 error[E0425]: cannot find value `x` in this scope
-  --> $DIR/let-else-scope.rs:5:22
+  --> $DIR/let-else-scope.rs:3:22
    |
 LL |         panic!("{}", x);
    |                      ^ not found in this scope
diff --git a/src/test/ui/let-else/let-else-slicing-error.rs b/src/test/ui/let-else/let-else-slicing-error.rs
index 4022656a8f53..25770094bce9 100644
--- a/src/test/ui/let-else/let-else-slicing-error.rs
+++ b/src/test/ui/let-else/let-else-slicing-error.rs
@@ -1,5 +1,5 @@
 // issue #92069
-#![feature(let_else)]
+
 
 fn main() {
     let nums = vec![5, 4, 3, 2, 1];
diff --git a/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs b/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs
index 2aa17ae8ceb1..ee378abcf2ba 100644
--- a/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs
+++ b/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs
@@ -1,7 +1,7 @@
 // run-pass
 // issue #89688
 
-#![feature(let_else)]
+
 
 fn example_let_else(value: Option<String>) {
     let Some(inner) = value else {
diff --git a/src/test/ui/let-else/let-else-temp-borrowck.rs b/src/test/ui/let-else/let-else-temp-borrowck.rs
index 3910d35e7767..6b4642d2f985 100644
--- a/src/test/ui/let-else/let-else-temp-borrowck.rs
+++ b/src/test/ui/let-else/let-else-temp-borrowck.rs
@@ -3,7 +3,7 @@
 // from issue #93951, where borrowck complained the temporary that `foo(&x)` was stored in was to
 // be dropped sometime after `x` was. It then suggested adding a semicolon that was already there.
 
-#![feature(let_else)]
+
 use std::fmt::Debug;
 
 fn foo<'a>(x: &'a str) -> Result<impl Debug + 'a, ()> {
diff --git a/src/test/ui/let-else/let-else-temporary-lifetime.rs b/src/test/ui/let-else/let-else-temporary-lifetime.rs
index 07fcc16e7bbd..c23eaa997fe4 100644
--- a/src/test/ui/let-else/let-else-temporary-lifetime.rs
+++ b/src/test/ui/let-else/let-else-temporary-lifetime.rs
@@ -1,5 +1,5 @@
 // run-pass
-#![feature(let_else)]
+// compile-flags: -Zvalidate-mir
 
 use std::fmt::Display;
 use std::rc::Rc;
diff --git a/src/test/ui/let-else/let-else-then-diverge.rs b/src/test/ui/let-else/let-else-then-diverge.rs
index 49633d943bee..1c8f7d758e8a 100644
--- a/src/test/ui/let-else/let-else-then-diverge.rs
+++ b/src/test/ui/let-else/let-else-then-diverge.rs
@@ -2,7 +2,7 @@
 // popped up in in #94012, where an alternative desugaring was
 // causing unreachable code errors
 
-#![feature(let_else)]
+
 #![deny(unused_variables)]
 #![deny(unreachable_code)]
 
diff --git a/src/test/ui/let-else/let-else.rs b/src/test/ui/let-else/let-else.rs
new file mode 100644
index 000000000000..3505533e63f1
--- /dev/null
+++ b/src/test/ui/let-else/let-else.rs
@@ -0,0 +1,8 @@
+// run-pass
+
+fn main() {
+    let Some(x) = Some(1) else {
+        return;
+    };
+    assert_eq!(x, 1);
+}
diff --git a/src/test/ui/lexer/lex-emoji-identifiers.rs b/src/test/ui/lexer/lex-emoji-identifiers.rs
new file mode 100644
index 000000000000..91b5929c0fea
--- /dev/null
+++ b/src/test/ui/lexer/lex-emoji-identifiers.rs
@@ -0,0 +1,17 @@
+fn invalid_emoji_usages() {
+    let arrow↔️ = "basic emoji"; //~ ERROR: identifiers cannot contain emoji
+    // FIXME
+    let planet🪐 = "basic emoji"; //~ ERROR: unknown start of token
+    // FIXME
+    let wireless🛜 = "basic emoji"; //~ ERROR: unknown start of token
+    // FIXME
+    let key1️⃣ = "keycap sequence"; //~ ERROR: unknown start of token
+                                    //~^ WARN: identifier contains uncommon Unicode codepoints
+    let flag🇺🇳 = "flag sequence"; //~ ERROR: identifiers cannot contain emoji
+    let wales🏴 = "tag sequence"; //~ ERROR: identifiers cannot contain emoji
+    let folded🙏🏿 = "modifier sequence"; //~ ERROR: identifiers cannot contain emoji
+}
+
+fn main() {
+    invalid_emoji_usages();
+}
diff --git a/src/test/ui/lexer/lex-emoji-identifiers.stderr b/src/test/ui/lexer/lex-emoji-identifiers.stderr
new file mode 100644
index 000000000000..6237c5d0236d
--- /dev/null
+++ b/src/test/ui/lexer/lex-emoji-identifiers.stderr
@@ -0,0 +1,52 @@
+error: unknown start of token: \u{1fa90}
+  --> $DIR/lex-emoji-identifiers.rs:4:15
+   |
+LL |     let planet🪐 = "basic emoji";
+   |               ^^
+
+error: unknown start of token: \u{1f6dc}
+  --> $DIR/lex-emoji-identifiers.rs:6:17
+   |
+LL |     let wireless🛜 = "basic emoji";
+   |                 ^^
+
+error: unknown start of token: \u{20e3}
+  --> $DIR/lex-emoji-identifiers.rs:8:14
+   |
+LL |     let key1️⃣ = "keycap sequence";
+   |             ^
+
+error: identifiers cannot contain emoji: `arrow↔️`
+  --> $DIR/lex-emoji-identifiers.rs:2:9
+   |
+LL |     let arrow↔️ = "basic emoji";
+   |         ^^^^^^
+
+error: identifiers cannot contain emoji: `flag🇺🇳`
+  --> $DIR/lex-emoji-identifiers.rs:10:9
+   |
+LL |     let flag🇺🇳 = "flag sequence";
+   |         ^^^^^^
+
+error: identifiers cannot contain emoji: `wales🏴`
+  --> $DIR/lex-emoji-identifiers.rs:11:9
+   |
+LL |     let wales🏴 = "tag sequence";
+   |         ^^^^^^^
+
+error: identifiers cannot contain emoji: `folded🙏🏿`
+  --> $DIR/lex-emoji-identifiers.rs:12:9
+   |
+LL |     let folded🙏🏿 = "modifier sequence";
+   |         ^^^^^^^^^^
+
+warning: identifier contains uncommon Unicode codepoints
+  --> $DIR/lex-emoji-identifiers.rs:8:9
+   |
+LL |     let key1️⃣ = "keycap sequence";
+   |         ^^^^
+   |
+   = note: `#[warn(uncommon_codepoints)]` on by default
+
+error: aborting due to 7 previous errors; 1 warning emitted
+
diff --git a/src/test/ui/lexical-scopes.stderr b/src/test/ui/lexical-scopes.stderr
index ad11f72a31d3..08e4be2c0c35 100644
--- a/src/test/ui/lexical-scopes.stderr
+++ b/src/test/ui/lexical-scopes.stderr
@@ -2,7 +2,7 @@ error[E0574]: expected struct, variant or union type, found type parameter `T`
   --> $DIR/lexical-scopes.rs:3:13
    |
 LL | fn f<T>() {
-   |      - found this type pararmeter
+   |      - found this type parameter
 LL |     let t = T { i: 0 };
    |             ^ not a struct, variant or union type
 
diff --git a/src/test/ui/lifetimes/issue-26638.stderr b/src/test/ui/lifetimes/issue-26638.stderr
index f3af5cf5a357..98d39d614d0e 100644
--- a/src/test/ui/lifetimes/issue-26638.stderr
+++ b/src/test/ui/lifetimes/issue-26638.stderr
@@ -54,7 +54,7 @@ LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
 help: provide the argument
    |
 LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter(/* &u8 */) }
-   |                                               ~~~~~~~~~~~~~~~
+   |                                                   ~~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/issue-26638.rs:5:47
diff --git a/src/test/ui/lifetimes/issue-79187-2.stderr b/src/test/ui/lifetimes/issue-79187-2.stderr
index 9322e617176a..c5f654b37bf6 100644
--- a/src/test/ui/lifetimes/issue-79187-2.stderr
+++ b/src/test/ui/lifetimes/issue-79187-2.stderr
@@ -31,7 +31,7 @@ error[E0308]: mismatched types
 LL |     take_foo(|a| a);
    |     ^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r> Fn<(&'r i32,)>`
+   = note: expected trait `for<'a> Fn<(&'a i32,)>`
               found trait `Fn<(&i32,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-79187-2.rs:8:14
diff --git a/src/test/ui/lifetimes/issue-79187.stderr b/src/test/ui/lifetimes/issue-79187.stderr
index 3e75e7fed2cc..ee6e7b89d5f0 100644
--- a/src/test/ui/lifetimes/issue-79187.stderr
+++ b/src/test/ui/lifetimes/issue-79187.stderr
@@ -4,7 +4,7 @@ error[E0308]: mismatched types
 LL |     thing(f);
    |     ^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r> FnOnce<(&'r u32,)>`
+   = note: expected trait `for<'a> FnOnce<(&'a u32,)>`
               found trait `FnOnce<(&u32,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-79187.rs:4:13
diff --git a/src/test/ui/lifetimes/lifetime-errors/issue_74400.stderr b/src/test/ui/lifetimes/lifetime-errors/issue_74400.stderr
index d82b2684cce5..7049f28e2f6e 100644
--- a/src/test/ui/lifetimes/lifetime-errors/issue_74400.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/issue_74400.stderr
@@ -15,7 +15,7 @@ error[E0308]: mismatched types
 LL |     f(data, identity)
    |     ^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r> Fn<(&'r T,)>`
+   = note: expected trait `for<'a> Fn<(&'a T,)>`
               found trait `Fn<(&T,)>`
 note: the lifetime requirement is introduced here
   --> $DIR/issue_74400.rs:8:34
diff --git a/src/test/ui/lifetimes/missing-lifetime-in-alias.rs b/src/test/ui/lifetimes/missing-lifetime-in-alias.rs
index af7b6412780d..51c564c011a8 100644
--- a/src/test/ui/lifetimes/missing-lifetime-in-alias.rs
+++ b/src/test/ui/lifetimes/missing-lifetime-in-alias.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Trait<'a> {
     type Foo;
 
diff --git a/src/test/ui/lifetimes/missing-lifetime-in-alias.stderr b/src/test/ui/lifetimes/missing-lifetime-in-alias.stderr
index b8c68a4607da..428b8f14b6fc 100644
--- a/src/test/ui/lifetimes/missing-lifetime-in-alias.stderr
+++ b/src/test/ui/lifetimes/missing-lifetime-in-alias.stderr
@@ -1,5 +1,5 @@
 error[E0106]: missing lifetime specifier
-  --> $DIR/missing-lifetime-in-alias.rs:22:24
+  --> $DIR/missing-lifetime-in-alias.rs:20:24
    |
 LL | type B<'a> = <A<'a> as Trait>::Foo;
    |                        ^^^^^ expected named lifetime parameter
@@ -10,13 +10,13 @@ LL | type B<'a> = <A<'a> as Trait<'a>>::Foo;
    |                             ++++
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/missing-lifetime-in-alias.rs:26:28
+  --> $DIR/missing-lifetime-in-alias.rs:24:28
    |
 LL | type C<'a, 'b> = <A<'a> as Trait>::Bar;
    |                            ^^^^^ expected named lifetime parameter
    |
 note: these named lifetimes are available to use
-  --> $DIR/missing-lifetime-in-alias.rs:26:8
+  --> $DIR/missing-lifetime-in-alias.rs:24:8
    |
 LL | type C<'a, 'b> = <A<'a> as Trait>::Bar;
    |        ^^  ^^
@@ -26,13 +26,13 @@ LL | type C<'a, 'b> = <A<'a> as Trait<'lifetime>>::Bar;
    |                                 +++++++++++
 
 error[E0107]: missing generics for associated type `Trait::Bar`
-  --> $DIR/missing-lifetime-in-alias.rs:26:36
+  --> $DIR/missing-lifetime-in-alias.rs:24:36
    |
 LL | type C<'a, 'b> = <A<'a> as Trait>::Bar;
    |                                    ^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'b`
-  --> $DIR/missing-lifetime-in-alias.rs:6:10
+  --> $DIR/missing-lifetime-in-alias.rs:4:10
    |
 LL |     type Bar<'b>
    |          ^^^ --
diff --git a/src/test/ui/lifetimes/re-empty-in-error.stderr b/src/test/ui/lifetimes/re-empty-in-error.stderr
index 72bb0782f4b4..840707d94708 100644
--- a/src/test/ui/lifetimes/re-empty-in-error.stderr
+++ b/src/test/ui/lifetimes/re-empty-in-error.stderr
@@ -4,7 +4,7 @@ error: higher-ranked lifetime error
 LL |     foo(&10);
    |     ^^^^^^^^
    |
-   = note: could not prove `for<'b, 'r> &'b (): 'r`
+   = note: could not prove `for<'b, 'a> &'b (): 'a`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs b/src/test/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs
new file mode 100644
index 000000000000..645bc7db0dda
--- /dev/null
+++ b/src/test/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs
@@ -0,0 +1,9 @@
+fn no_restriction<T>(x: &()) -> &() {
+    with_restriction::<T>(x) //~ ERROR the parameter type `T` may not live long enough
+}
+
+fn with_restriction<'b, T: 'b>(x: &'b ()) -> &'b () {
+    x
+}
+
+fn main() {}
diff --git a/src/test/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr b/src/test/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
new file mode 100644
index 000000000000..a8b0996d8b0c
--- /dev/null
+++ b/src/test/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
@@ -0,0 +1,23 @@
+error[E0311]: the parameter type `T` may not live long enough
+  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:2:5
+   |
+LL |     with_restriction::<T>(x)
+   |     ^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the parameter type `T` must be valid for the anonymous lifetime defined here...
+  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:1:25
+   |
+LL | fn no_restriction<T>(x: &()) -> &() {
+   |                         ^^^
+note: ...so that the type `T` will meet its required lifetime bounds
+  --> $DIR/suggest-introducing-and-adding-missing-lifetime.rs:2:5
+   |
+LL |     with_restriction::<T>(x)
+   |     ^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn no_restriction<'a, T: 'a>(x: &()) -> &() {
+   |                   +++  ++++
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/lint/force-warn/allowed-group-warn-by-default-lint.stderr b/src/test/ui/lint/force-warn/allowed-group-warn-by-default-lint.stderr
index 8d826bd14576..94d81c3aa71b 100644
--- a/src/test/ui/lint/force-warn/allowed-group-warn-by-default-lint.stderr
+++ b/src/test/ui/lint/force-warn/allowed-group-warn-by-default-lint.stderr
@@ -9,9 +9,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/allowed-group-warn-by-default-lint.rs:10:25
@@ -23,9 +22,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/allowed-group-warn-by-default-lint.rs:10:25
@@ -37,9 +35,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: 3 warnings emitted
 
diff --git a/src/test/ui/lint/force-warn/cap-lints-allow.stderr b/src/test/ui/lint/force-warn/cap-lints-allow.stderr
index 978270872c45..7f0fd8530e2c 100644
--- a/src/test/ui/lint/force-warn/cap-lints-allow.stderr
+++ b/src/test/ui/lint/force-warn/cap-lints-allow.stderr
@@ -9,9 +9,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/cap-lints-allow.rs:8:25
@@ -23,9 +22,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/cap-lints-allow.rs:8:25
@@ -37,9 +35,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: 3 warnings emitted
 
diff --git a/src/test/ui/lint/force-warn/lint-group-allowed-cli-warn-by-default-lint.stderr b/src/test/ui/lint/force-warn/lint-group-allowed-cli-warn-by-default-lint.stderr
index 6e67ebf27473..eb2bca7b84d7 100644
--- a/src/test/ui/lint/force-warn/lint-group-allowed-cli-warn-by-default-lint.stderr
+++ b/src/test/ui/lint/force-warn/lint-group-allowed-cli-warn-by-default-lint.stderr
@@ -9,9 +9,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/lint-group-allowed-cli-warn-by-default-lint.rs:8:25
@@ -23,9 +22,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/lint-group-allowed-cli-warn-by-default-lint.rs:8:25
@@ -37,9 +35,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: 3 warnings emitted
 
diff --git a/src/test/ui/lint/force-warn/lint-group-allowed-lint-group.stderr b/src/test/ui/lint/force-warn/lint-group-allowed-lint-group.stderr
index c5dea84b8f35..ed01937a57b1 100644
--- a/src/test/ui/lint/force-warn/lint-group-allowed-lint-group.stderr
+++ b/src/test/ui/lint/force-warn/lint-group-allowed-lint-group.stderr
@@ -9,9 +9,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/lint-group-allowed-lint-group.rs:10:25
@@ -23,9 +22,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/lint-group-allowed-lint-group.rs:10:25
@@ -37,9 +35,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: 3 warnings emitted
 
diff --git a/src/test/ui/lint/force-warn/lint-group-allowed-warn-by-default-lint.stderr b/src/test/ui/lint/force-warn/lint-group-allowed-warn-by-default-lint.stderr
index acd0c503d9c0..8db7c12757b0 100644
--- a/src/test/ui/lint/force-warn/lint-group-allowed-warn-by-default-lint.stderr
+++ b/src/test/ui/lint/force-warn/lint-group-allowed-warn-by-default-lint.stderr
@@ -9,9 +9,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/lint-group-allowed-warn-by-default-lint.rs:10:25
@@ -23,9 +22,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: trait objects without an explicit `dyn` are deprecated
   --> $DIR/lint-group-allowed-warn-by-default-lint.rs:10:25
@@ -37,9 +35,8 @@ LL | pub fn function(_x: Box<SomeTrait>) {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub fn function(_x: Box<SomeTrait>) {}
-LL + pub fn function(_x: Box<dyn SomeTrait>) {}
-   |
+LL | pub fn function(_x: Box<dyn SomeTrait>) {}
+   |                         +++
 
 warning: 3 warnings emitted
 
diff --git a/src/test/ui/lint/issue-101284.rs b/src/test/ui/lint/issue-101284.rs
new file mode 100644
index 000000000000..1381d4f17272
--- /dev/null
+++ b/src/test/ui/lint/issue-101284.rs
@@ -0,0 +1,15 @@
+// check-pass
+// edition:2021
+#![deny(rust_2021_compatibility)]
+
+pub struct Warns {
+    // `Arc` has significant drop
+    _significant_drop: std::sync::Arc<()>,
+    field: String,
+}
+
+pub fn test(w: Warns) {
+    _ = || drop(w.field);
+}
+
+fn main() {}
diff --git a/src/test/ui/lint/issue-70819-dont-override-forbid-in-same-scope.rs b/src/test/ui/lint/issue-70819-dont-override-forbid-in-same-scope.rs
index c66037e9a73a..b4fc3317487d 100644
--- a/src/test/ui/lint/issue-70819-dont-override-forbid-in-same-scope.rs
+++ b/src/test/ui/lint/issue-70819-dont-override-forbid-in-same-scope.rs
@@ -5,7 +5,7 @@
 // If you turn off deduplicate diagnostics (which rustc turns on by default but
 // compiletest turns off when it runs ui tests), then the errors are
 // (unfortunately) repeated here because the checking is done as we read in the
-// errors, and curretly that happens two or three different times, depending on
+// errors, and currently that happens two or three different times, depending on
 // compiler flags.
 //
 // I decided avoiding the redundant output was not worth the time in engineering
diff --git a/src/test/ui/lint/let_underscore/let_underscore_drop.rs b/src/test/ui/lint/let_underscore/let_underscore_drop.rs
new file mode 100644
index 000000000000..f298871f122d
--- /dev/null
+++ b/src/test/ui/lint/let_underscore/let_underscore_drop.rs
@@ -0,0 +1,14 @@
+// check-pass
+#![warn(let_underscore_drop)]
+
+struct NontrivialDrop;
+
+impl Drop for NontrivialDrop {
+    fn drop(&mut self) {
+        println!("Dropping!");
+    }
+}
+
+fn main() {
+    let _ = NontrivialDrop; //~WARNING non-binding let on a type that implements `Drop`
+}
diff --git a/src/test/ui/lint/let_underscore/let_underscore_drop.stderr b/src/test/ui/lint/let_underscore/let_underscore_drop.stderr
new file mode 100644
index 000000000000..7b7de202e462
--- /dev/null
+++ b/src/test/ui/lint/let_underscore/let_underscore_drop.stderr
@@ -0,0 +1,22 @@
+warning: non-binding let on a type that implements `Drop`
+  --> $DIR/let_underscore_drop.rs:13:5
+   |
+LL |     let _ = NontrivialDrop;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/let_underscore_drop.rs:2:9
+   |
+LL | #![warn(let_underscore_drop)]
+   |         ^^^^^^^^^^^^^^^^^^^
+help: consider binding to an unused variable to avoid immediately dropping the value
+   |
+LL |     let _unused = NontrivialDrop;
+   |         ~~~~~~~
+help: consider immediately dropping the value
+   |
+LL |     drop(NontrivialDrop);
+   |     ~~~~~              +
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/lint/let_underscore/let_underscore_lock.rs b/src/test/ui/lint/let_underscore/let_underscore_lock.rs
new file mode 100644
index 000000000000..7423862cdf05
--- /dev/null
+++ b/src/test/ui/lint/let_underscore/let_underscore_lock.rs
@@ -0,0 +1,7 @@
+// check-fail
+use std::sync::{Arc, Mutex};
+
+fn main() {
+    let data = Arc::new(Mutex::new(0));
+    let _ = data.lock().unwrap(); //~ERROR non-binding let on a synchronization lock
+}
diff --git a/src/test/ui/lint/let_underscore/let_underscore_lock.stderr b/src/test/ui/lint/let_underscore/let_underscore_lock.stderr
new file mode 100644
index 000000000000..fb58af0a42f8
--- /dev/null
+++ b/src/test/ui/lint/let_underscore/let_underscore_lock.stderr
@@ -0,0 +1,20 @@
+error: non-binding let on a synchronization lock
+  --> $DIR/let_underscore_lock.rs:6:9
+   |
+LL |     let _ = data.lock().unwrap();
+   |         ^   ^^^^^^^^^^^^^^^^^^^^ this binding will immediately drop the value assigned to it
+   |         |
+   |         this lock is not assigned to a binding and is immediately dropped
+   |
+   = note: `#[deny(let_underscore_lock)]` on by default
+help: consider binding to an unused variable to avoid immediately dropping the value
+   |
+LL |     let _unused = data.lock().unwrap();
+   |         ~~~~~~~
+help: consider immediately dropping the value
+   |
+LL |     drop(data.lock().unwrap());
+   |     ~~~~~                    +
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/lint/must_not_suspend/ref.drop_tracking.stderr b/src/test/ui/lint/must_not_suspend/ref.drop_tracking.stderr
new file mode 100644
index 000000000000..0157c8b7fe10
--- /dev/null
+++ b/src/test/ui/lint/must_not_suspend/ref.drop_tracking.stderr
@@ -0,0 +1,27 @@
+error: reference to `Umm` held across a suspend point, but should not be
+  --> $DIR/ref.rs:21:13
+   |
+LL |         let guard = &mut self.u;
+   |             ^^^^^
+LL |
+LL |         other().await;
+   |                ------ the value is held across this suspend point
+   |
+note: the lint level is defined here
+  --> $DIR/ref.rs:6:9
+   |
+LL | #![deny(must_not_suspend)]
+   |         ^^^^^^^^^^^^^^^^
+note: You gotta use Umm's, ya know?
+  --> $DIR/ref.rs:21:13
+   |
+LL |         let guard = &mut self.u;
+   |             ^^^^^
+help: consider using a block (`{ ... }`) to shrink the value's scope, ending before the suspend point
+  --> $DIR/ref.rs:21:13
+   |
+LL |         let guard = &mut self.u;
+   |             ^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/lint/must_not_suspend/ref.stderr b/src/test/ui/lint/must_not_suspend/ref.no_drop_tracking.stderr
similarity index 88%
rename from src/test/ui/lint/must_not_suspend/ref.stderr
rename to src/test/ui/lint/must_not_suspend/ref.no_drop_tracking.stderr
index 5f000014c7db..438e6489e31c 100644
--- a/src/test/ui/lint/must_not_suspend/ref.stderr
+++ b/src/test/ui/lint/must_not_suspend/ref.no_drop_tracking.stderr
@@ -1,5 +1,5 @@
 error: `Umm` held across a suspend point, but should not be
-  --> $DIR/ref.rs:18:26
+  --> $DIR/ref.rs:21:26
    |
 LL |         let guard = &mut self.u;
    |                          ^^^^^^
@@ -8,17 +8,17 @@ LL |         other().await;
    |                ------ the value is held across this suspend point
    |
 note: the lint level is defined here
-  --> $DIR/ref.rs:3:9
+  --> $DIR/ref.rs:6:9
    |
 LL | #![deny(must_not_suspend)]
    |         ^^^^^^^^^^^^^^^^
 note: You gotta use Umm's, ya know?
-  --> $DIR/ref.rs:18:26
+  --> $DIR/ref.rs:21:26
    |
 LL |         let guard = &mut self.u;
    |                          ^^^^^^
 help: consider using a block (`{ ... }`) to shrink the value's scope, ending before the suspend point
-  --> $DIR/ref.rs:18:26
+  --> $DIR/ref.rs:21:26
    |
 LL |         let guard = &mut self.u;
    |                          ^^^^^^
diff --git a/src/test/ui/lint/must_not_suspend/ref.rs b/src/test/ui/lint/must_not_suspend/ref.rs
index 738dd9e04655..f6b23746fef1 100644
--- a/src/test/ui/lint/must_not_suspend/ref.rs
+++ b/src/test/ui/lint/must_not_suspend/ref.rs
@@ -1,10 +1,13 @@
 // edition:2018
+// revisions: no_drop_tracking drop_tracking
+// [drop_tracking] compile-flags: -Zdrop-tracking=yes
+// [no_drop_tracking] compile-flags: -Zdrop-tracking=no
 #![feature(must_not_suspend)]
 #![deny(must_not_suspend)]
 
 #[must_not_suspend = "You gotta use Umm's, ya know?"]
 struct Umm {
-    i: i64
+    i: i64,
 }
 
 struct Bar {
@@ -19,11 +22,8 @@ impl Bar {
 
         other().await;
 
-        *guard = Umm {
-            i: 2
-        }
+        *guard = Umm { i: 2 }
     }
 }
 
-fn main() {
-}
+fn main() {}
diff --git a/src/test/ui/loops/loop-proper-liveness.stderr b/src/test/ui/loops/loop-proper-liveness.stderr
index 14e86aee059b..f9d94b6810cb 100644
--- a/src/test/ui/loops/loop-proper-liveness.stderr
+++ b/src/test/ui/loops/loop-proper-liveness.stderr
@@ -8,6 +8,10 @@ LL |     println!("{:?}", x);
    |                      ^ `x` used here but it isn't initialized
    |
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let x: i32 = 0;
+   |                +++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/macro-comma-behavior-rpass.rs b/src/test/ui/macros/macro-comma-behavior-rpass.rs
index dfd58b25d089..8406b4e78f6b 100644
--- a/src/test/ui/macros/macro-comma-behavior-rpass.rs
+++ b/src/test/ui/macros/macro-comma-behavior-rpass.rs
@@ -14,7 +14,6 @@
 // compile-flags: --test -C debug_assertions=yes
 // revisions: std core
 
-// ignore-wasm32-bare compiled with panic=abort by default
 #![cfg_attr(core, no_std)]
 
 #[cfg(core)]
diff --git a/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-expr-kinds.rs b/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-expr-kinds.rs
index f538ec643902..b8b6f0846bb4 100644
--- a/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-expr-kinds.rs
+++ b/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-expr-kinds.rs
@@ -2,6 +2,7 @@
 // ignore-tidy-linelength
 // only-x86_64
 // run-pass
+// needs-unwind Asserting on contents of error message
 
 #![allow(path_statements, unused_allocation)]
 #![feature(box_syntax, core_intrinsics, generic_assert, generic_assert_internals)]
diff --git a/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-not-available-cases.rs b/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-not-available-cases.rs
index 86697c58fbcf..d46f396ee297 100644
--- a/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-not-available-cases.rs
+++ b/src/test/ui/macros/rfc-2011-nicer-assert-messages/all-not-available-cases.rs
@@ -2,6 +2,7 @@
 // ignore-tidy-linelength
 // only-x86_64
 // run-pass
+// needs-unwind Asserting on contents of error message
 
 #![feature(core_intrinsics, generic_assert, generic_assert_internals)]
 
diff --git a/src/test/ui/macros/rfc-2011-nicer-assert-messages/assert-without-captures-does-not-create-unnecessary-code.rs b/src/test/ui/macros/rfc-2011-nicer-assert-messages/assert-without-captures-does-not-create-unnecessary-code.rs
index 06c4993ec30d..1f5a29ab524f 100644
--- a/src/test/ui/macros/rfc-2011-nicer-assert-messages/assert-without-captures-does-not-create-unnecessary-code.rs
+++ b/src/test/ui/macros/rfc-2011-nicer-assert-messages/assert-without-captures-does-not-create-unnecessary-code.rs
@@ -1,6 +1,7 @@
 // aux-build:common.rs
 // only-x86_64
 // run-pass
+// needs-unwind Asserting on contents of error message
 
 #![feature(core_intrinsics, generic_assert, generic_assert_internals)]
 
diff --git a/src/test/ui/macros/syntax-error-recovery.rs b/src/test/ui/macros/syntax-error-recovery.rs
new file mode 100644
index 000000000000..ae6de3c5046c
--- /dev/null
+++ b/src/test/ui/macros/syntax-error-recovery.rs
@@ -0,0 +1,18 @@
+macro_rules! values {
+    ($($token:ident($value:literal) $(as $inner:ty)? => $attr:meta,)*) => {
+        #[derive(Debug)]
+        pub enum TokenKind {
+            $(
+                #[$attr]
+                $token $($inner)? = $value,
+            )*
+        }
+    };
+}
+//~^^^^^ ERROR expected one of `(`, `,`, `=`, `{`, or `}`, found `(String)`
+//~| ERROR macro expansion ignores token `(String)` and any following
+
+values!(STRING(1) as (String) => cfg(test),);
+//~^ ERROR expected one of `!` or `::`, found `<eof>`
+
+fn main() {}
diff --git a/src/test/ui/macros/syntax-error-recovery.stderr b/src/test/ui/macros/syntax-error-recovery.stderr
new file mode 100644
index 000000000000..c153b3b910bb
--- /dev/null
+++ b/src/test/ui/macros/syntax-error-recovery.stderr
@@ -0,0 +1,30 @@
+error: expected one of `(`, `,`, `=`, `{`, or `}`, found `(String)`
+  --> $DIR/syntax-error-recovery.rs:7:26
+   |
+LL |                 $token $($inner)? = $value,
+   |                          ^^^^^^ expected one of `(`, `,`, `=`, `{`, or `}`
+...
+LL | values!(STRING(1) as (String) => cfg(test),);
+   | -------------------------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `values` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: macro expansion ignores token `(String)` and any following
+  --> $DIR/syntax-error-recovery.rs:7:26
+   |
+LL |                 $token $($inner)? = $value,
+   |                          ^^^^^^
+...
+LL | values!(STRING(1) as (String) => cfg(test),);
+   | -------------------------------------------- caused by the macro expansion here
+   |
+   = note: the usage of `values!` is likely invalid in item context
+
+error: expected one of `!` or `::`, found `<eof>`
+  --> $DIR/syntax-error-recovery.rs:15:9
+   |
+LL | values!(STRING(1) as (String) => cfg(test),);
+   |         ^^^^^^ expected one of `!` or `::`
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/match/match_non_exhaustive.rs b/src/test/ui/match/match_non_exhaustive.rs
index 8219f0eb1357..f162dd60f503 100644
--- a/src/test/ui/match/match_non_exhaustive.rs
+++ b/src/test/ui/match/match_non_exhaustive.rs
@@ -21,7 +21,7 @@ fn main() {
     match l { L::A => (), L::B => () };
     // (except if the match is already non-exhaustive)
     match l { L::A => () };
-    //~^ ERROR: non-exhaustive patterns: `B` not covered [E0004]
+    //~^ ERROR: non-exhaustive patterns: `L::B` not covered [E0004]
 
     // E1 is not visibly uninhabited from here
     let (e1, e2) = bar();
diff --git a/src/test/ui/match/match_non_exhaustive.stderr b/src/test/ui/match/match_non_exhaustive.stderr
index 9d92f8fdbb4b..46ee8d5179e6 100644
--- a/src/test/ui/match/match_non_exhaustive.stderr
+++ b/src/test/ui/match/match_non_exhaustive.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `B` not covered
+error[E0004]: non-exhaustive patterns: `L::B` not covered
   --> $DIR/match_non_exhaustive.rs:23:11
    |
 LL |     match l { L::A => () };
-   |           ^ pattern `B` not covered
+   |           ^ pattern `L::B` not covered
    |
 note: `L` defined here
   --> $DIR/match_non_exhaustive.rs:10:13
@@ -12,8 +12,8 @@ LL | enum L { A, B }
    = note: the matched value is of type `L`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL |     match l { L::A => (), B => todo!() };
-   |                         ++++++++++++++
+LL |     match l { L::A => (), L::B => todo!() };
+   |                         +++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: type `E1` is non-empty
   --> $DIR/match_non_exhaustive.rs:28:11
diff --git a/src/test/ui/methods/method-call-err-msg.stderr b/src/test/ui/methods/method-call-err-msg.stderr
index e9b49c89bf16..a4ffb864dad9 100644
--- a/src/test/ui/methods/method-call-err-msg.stderr
+++ b/src/test/ui/methods/method-call-err-msg.stderr
@@ -12,7 +12,7 @@ LL |     fn zero(self) -> Foo { self }
 help: remove the extra argument
    |
 LL |     x.zero()
-   |       ~~~~~~
+   |           ~~
 
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/method-call-err-msg.rs:14:7
@@ -28,7 +28,7 @@ LL |     fn one(self, _: isize) -> Foo { self }
 help: provide the argument
    |
 LL |      .one(/* isize */)
-   |       ~~~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 1 argument was supplied
   --> $DIR/method-call-err-msg.rs:15:7
@@ -44,7 +44,7 @@ LL |     fn two(self, _: isize, _: isize) -> Foo { self }
 help: provide the argument
    |
 LL |      .two(0, /* isize */);
-   |       ~~~~~~~~~~~~~~~~~~~
+   |          ~~~~~~~~~~~~~~~~
 
 error[E0599]: `Foo` is not an iterator
   --> $DIR/method-call-err-msg.rs:19:7
@@ -84,7 +84,7 @@ LL |     fn three<T>(self, _: T, _: T, _: T) -> Foo { self }
 help: provide the arguments
    |
 LL |     y.three::<usize>(/* usize */, /* usize */, /* usize */);
-   |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/mir/drop-elaboration-after-borrowck-error.rs b/src/test/ui/mir/drop-elaboration-after-borrowck-error.rs
index fc7341a563bb..624b464ecef2 100644
--- a/src/test/ui/mir/drop-elaboration-after-borrowck-error.rs
+++ b/src/test/ui/mir/drop-elaboration-after-borrowck-error.rs
@@ -3,9 +3,9 @@
 
 static A: () = {
     let a: [String; 1];
-    //~^ ERROR destructors cannot be evaluated at compile-time
+    //~^ ERROR destructor of
     a[0] = String::new();
-    //~^ ERROR destructors cannot be evaluated at compile-time
+    //~^ ERROR destructor of
     //~| ERROR binding `a` isn't initialized
 };
 
@@ -14,9 +14,9 @@ struct B<T>([T; 1]);
 impl<T> B<T> {
     pub const fn f(mut self, other: T) -> Self {
         let _this = self;
-        //~^ ERROR destructors cannot be evaluated at compile-time
+        //~^ ERROR destructor of
         self.0[0] = other;
-        //~^ ERROR destructors cannot be evaluated at compile-time
+        //~^ ERROR destructor of
         //~| ERROR use of moved value
         self
     }
diff --git a/src/test/ui/mir/drop-elaboration-after-borrowck-error.stderr b/src/test/ui/mir/drop-elaboration-after-borrowck-error.stderr
index d8154f8d2cbc..d961061729d4 100644
--- a/src/test/ui/mir/drop-elaboration-after-borrowck-error.stderr
+++ b/src/test/ui/mir/drop-elaboration-after-borrowck-error.stderr
@@ -1,17 +1,17 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `String` cannot be evaluated at compile-time
   --> $DIR/drop-elaboration-after-borrowck-error.rs:7:5
    |
 LL |     a[0] = String::new();
    |     ^^^^
    |     |
-   |     statics cannot evaluate destructors
+   |     the destructor for this type cannot be evaluated in statics
    |     value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `[String; 1]` cannot be evaluated at compile-time
   --> $DIR/drop-elaboration-after-borrowck-error.rs:5:9
    |
 LL |     let a: [String; 1];
-   |         ^ statics cannot evaluate destructors
+   |         ^ the destructor for this type cannot be evaluated in statics
 ...
 LL | };
    | - value is dropped here
@@ -24,21 +24,26 @@ LL |     let a: [String; 1];
 LL |
 LL |     a[0] = String::new();
    |     ^^^^ `a` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let a: [String; 1] = todo!();
+   |                        +++++++++
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `T` cannot be evaluated at compile-time
   --> $DIR/drop-elaboration-after-borrowck-error.rs:18:9
    |
 LL |         self.0[0] = other;
    |         ^^^^^^^^^
    |         |
-   |         constant functions cannot evaluate destructors
+   |         the destructor for this type cannot be evaluated in constant functions
    |         value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `B<T>` cannot be evaluated at compile-time
   --> $DIR/drop-elaboration-after-borrowck-error.rs:16:13
    |
 LL |         let _this = self;
-   |             ^^^^^ constant functions cannot evaluate destructors
+   |             ^^^^^ the destructor for this type cannot be evaluated in constant functions
 ...
 LL |     }
    |     - value is dropped here
diff --git a/src/test/ui/mir/issue-101844.rs b/src/test/ui/mir/issue-101844.rs
new file mode 100644
index 000000000000..da8a25f5f822
--- /dev/null
+++ b/src/test/ui/mir/issue-101844.rs
@@ -0,0 +1,73 @@
+// check-pass
+
+pub trait FirstTrait {
+    type Item;
+    type Extra: Extra<(), Error = Self::Item>;
+}
+
+trait SecondTrait {
+    type Item2;
+}
+
+trait ThirdTrait: SecondTrait {
+    type Item3;
+}
+
+trait FourthTrait {
+    type Item4;
+}
+
+impl<First> SecondTrait for First
+where
+    First: FirstTrait,
+{
+    type Item2 = First::Extra;
+}
+
+impl<Second, T> ThirdTrait for Second
+where
+    Second: SecondTrait<Item2 = T>,
+{
+    type Item3 = T;
+}
+
+impl<S, Third: ?Sized> FourthTrait for Third
+where
+    Third: ThirdTrait<Item3 = S>,
+{
+    type Item4 = S;
+}
+
+pub trait Extra<Request> {
+    type Error;
+}
+
+struct ImplShoulExist<D, Req> {
+    _gen: (D, Req),
+}
+
+impl<D, Req> ImplShoulExist<D, Req>
+where
+    D: FourthTrait,
+    D::Item4: Extra<Req>,
+    <D::Item4 as Extra<Req>>::Error: Into<()>,
+{
+    fn access_fn(_: D) {
+        todo!()
+    }
+}
+
+impl<D, Req> Extra<Req> for ImplShoulExist<D, Req> {
+    type Error = ();
+}
+
+pub fn broken<MS>(ms: MS)
+where
+    MS: FirstTrait,
+    MS::Item: Into<()>,
+{
+    // Error: Apparently Balance::new doesn't exist during MIR validation
+    let _ = ImplShoulExist::<MS, ()>::access_fn(ms);
+}
+
+fn main() {}
diff --git a/src/test/ui/mir/issue-99866.rs b/src/test/ui/mir/issue-99866.rs
new file mode 100644
index 000000000000..d39ae6ebf1da
--- /dev/null
+++ b/src/test/ui/mir/issue-99866.rs
@@ -0,0 +1,25 @@
+// check-pass
+pub trait Backend {
+    type DescriptorSetLayout;
+}
+
+pub struct Back;
+
+impl Backend for Back {
+    type DescriptorSetLayout = u32;
+}
+
+pub struct HalSetLayouts {
+    vertex_layout: <Back as Backend>::DescriptorSetLayout,
+}
+
+impl HalSetLayouts {
+    pub fn iter<DSL>(self) -> DSL
+    where
+        Back: Backend<DescriptorSetLayout = DSL>,
+    {
+        self.vertex_layout
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/mir/mir_calls_to_shims.rs b/src/test/ui/mir/mir_calls_to_shims.rs
index 42eaab77da9f..9dc0acfbfda4 100644
--- a/src/test/ui/mir/mir_calls_to_shims.rs
+++ b/src/test/ui/mir/mir_calls_to_shims.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(fn_traits)]
 #![feature(never_type)]
diff --git a/src/test/ui/mir/mir_codegen_calls_diverging_drops.rs b/src/test/ui/mir/mir_codegen_calls_diverging_drops.rs
index 796d74477939..19dba497001c 100644
--- a/src/test/ui/mir/mir_codegen_calls_diverging_drops.rs
+++ b/src/test/ui/mir/mir_codegen_calls_diverging_drops.rs
@@ -1,7 +1,7 @@
 // run-fail
 // error-pattern:diverging_fn called
 // error-pattern:0 dropped
-// ignore-emscripten no processes
+// needs-unwind this test checks that a destructor is called after panicking
 
 struct Droppable(u8);
 impl Drop for Droppable {
diff --git a/src/test/ui/mir/mir_drop_order.rs b/src/test/ui/mir/mir_drop_order.rs
index 853efb0fed2b..75f5b171af35 100644
--- a/src/test/ui/mir/mir_drop_order.rs
+++ b/src/test/ui/mir/mir_drop_order.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 use std::cell::RefCell;
 use std::panic;
diff --git a/src/test/ui/mir/mir_drop_panics.rs b/src/test/ui/mir/mir_drop_panics.rs
index b4093d704150..0d00426d6d2d 100644
--- a/src/test/ui/mir/mir_drop_panics.rs
+++ b/src/test/ui/mir/mir_drop_panics.rs
@@ -2,7 +2,6 @@
 // needs-unwind
 // error-pattern:panic 1
 // error-pattern:drop 2
-// ignore-emscripten no processes
 
 struct Droppable(u32);
 impl Drop for Droppable {
diff --git a/src/test/ui/mir/mir_let_chains_drop_order.rs b/src/test/ui/mir/mir_let_chains_drop_order.rs
index 6498a5195719..536a84a352a4 100644
--- a/src/test/ui/mir/mir_let_chains_drop_order.rs
+++ b/src/test/ui/mir/mir_let_chains_drop_order.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 // See `mir_drop_order.rs` for more information
 
diff --git a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
index 71469bfec2d3..92d545b7366e 100644
--- a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
+++ b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
@@ -23,7 +23,7 @@ LL |     a.iter().map(|_: &(u16, u16)| 45);
    |              expected due to this
    |
    = note: expected closure signature `fn(&(u32, u32)) -> _`
-              found closure signature `for<'r> fn(&'r (u16, u16)) -> _`
+              found closure signature `for<'a> fn(&'a (u16, u16)) -> _`
 note: required by a bound in `map`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
    |
diff --git a/src/test/ui/mismatched_types/closure-mismatch.stderr b/src/test/ui/mismatched_types/closure-mismatch.stderr
index ef76ec63fdaf..a7ef8fa08923 100644
--- a/src/test/ui/mismatched_types/closure-mismatch.stderr
+++ b/src/test/ui/mismatched_types/closure-mismatch.stderr
@@ -13,7 +13,7 @@ error[E0308]: mismatched types
 LL |     baz(|_| ());
    |     ^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r> Fn<(&'r (),)>`
+   = note: expected trait `for<'a> Fn<(&'a (),)>`
               found trait `Fn<(&(),)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/closure-mismatch.rs:8:9
diff --git a/src/test/ui/mismatched_types/fn-variance-1.stderr b/src/test/ui/mismatched_types/fn-variance-1.stderr
index eec6d83fe223..5794e606eeb9 100644
--- a/src/test/ui/mismatched_types/fn-variance-1.stderr
+++ b/src/test/ui/mismatched_types/fn-variance-1.stderr
@@ -10,7 +10,7 @@ LL |     apply(&3, takes_mut);
    |     required by a bound introduced by this call
    |
    = note: expected function signature `fn(&{integer}) -> _`
-              found function signature `for<'r> fn(&'r mut isize) -> _`
+              found function signature `for<'a> fn(&'a mut isize) -> _`
 note: required by a bound in `apply`
   --> $DIR/fn-variance-1.rs:5:37
    |
@@ -29,7 +29,7 @@ LL |     apply(&mut 3, takes_imm);
    |     required by a bound introduced by this call
    |
    = note: expected function signature `fn(&mut {integer}) -> _`
-              found function signature `for<'r> fn(&'r isize) -> _`
+              found function signature `for<'a> fn(&'a isize) -> _`
 note: required by a bound in `apply`
   --> $DIR/fn-variance-1.rs:5:37
    |
diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr
index b11ea97d160b..906001ca1e09 100644
--- a/src/test/ui/mismatched_types/issue-36053-2.stderr
+++ b/src/test/ui/mismatched_types/issue-36053-2.stderr
@@ -6,8 +6,8 @@ LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
    |                                |
    |                                expected due to this
    |
-   = note: expected closure signature `for<'r> fn(&'r &str) -> _`
-              found closure signature `for<'r> fn(&'r str) -> _`
+   = note: expected closure signature `for<'a> fn(&'a &str) -> _`
+              found closure signature `for<'a> fn(&'a str) -> _`
 note: required by a bound in `filter`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
    |
diff --git a/src/test/ui/mismatched_types/overloaded-calls-bad.stderr b/src/test/ui/mismatched_types/overloaded-calls-bad.stderr
index 475ea9dfaf1b..fb3597aa8530 100644
--- a/src/test/ui/mismatched_types/overloaded-calls-bad.stderr
+++ b/src/test/ui/mismatched_types/overloaded-calls-bad.stderr
@@ -26,7 +26,7 @@ LL | impl FnMut<(isize,)> for S {
 help: provide the argument
    |
 LL |     let ans = s(/* isize */);
-   |               ~~~~~~~~~~~~~~
+   |                ~~~~~~~~~~~~~
 
 error[E0057]: this function takes 1 argument but 2 arguments were supplied
   --> $DIR/overloaded-calls-bad.rs:31:15
@@ -44,7 +44,7 @@ LL | impl FnMut<(isize,)> for S {
 help: remove the extra argument
    |
 LL |     let ans = s(/* isize */);
-   |               ~~~~~~~~~~~~~~
+   |                ~~~~~~~~~~~~~
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/mismatched_types/show_module.rs b/src/test/ui/mismatched_types/show_module.rs
new file mode 100644
index 000000000000..61550b887552
--- /dev/null
+++ b/src/test/ui/mismatched_types/show_module.rs
@@ -0,0 +1,18 @@
+pub mod blah {
+    pub mod baz {
+        pub struct Foo;
+    }
+}
+
+pub mod meh {
+    pub struct Foo;
+}
+
+pub type Foo = blah::baz::Foo;
+
+fn foo() -> Foo {
+    meh::Foo
+    //~^ ERROR mismatched types [E0308]
+}
+
+fn main() {}
diff --git a/src/test/ui/mismatched_types/show_module.stderr b/src/test/ui/mismatched_types/show_module.stderr
new file mode 100644
index 000000000000..5e48e0955aae
--- /dev/null
+++ b/src/test/ui/mismatched_types/show_module.stderr
@@ -0,0 +1,23 @@
+error[E0308]: mismatched types
+  --> $DIR/show_module.rs:14:5
+   |
+LL | fn foo() -> Foo {
+   |             --- expected `baz::Foo` because of return type
+LL |     meh::Foo
+   |     ^^^^^^^^ expected struct `baz::Foo`, found struct `meh::Foo`
+   |
+   = note: struct `meh::Foo` and struct `baz::Foo` have similar names, but are actually distinct types
+note: struct `meh::Foo` is defined in module `crate::meh` of the current crate
+  --> $DIR/show_module.rs:8:5
+   |
+LL |     pub struct Foo;
+   |     ^^^^^^^^^^^^^^
+note: struct `baz::Foo` is defined in module `crate::blah::baz` of the current crate
+  --> $DIR/show_module.rs:3:9
+   |
+LL |         pub struct Foo;
+   |         ^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/mismatched_types/similar_paths.rs b/src/test/ui/mismatched_types/similar_paths.rs
new file mode 100644
index 000000000000..4b9157f39bf4
--- /dev/null
+++ b/src/test/ui/mismatched_types/similar_paths.rs
@@ -0,0 +1,11 @@
+enum Option<T> {
+    Some(T),
+    None,
+}
+
+pub fn foo() -> Option<u8> {
+    Some(42_u8)
+    //~^ ERROR mismatched types [E0308]
+}
+
+fn main() {}
diff --git a/src/test/ui/mismatched_types/similar_paths.stderr b/src/test/ui/mismatched_types/similar_paths.stderr
new file mode 100644
index 000000000000..e65ae58d4ce9
--- /dev/null
+++ b/src/test/ui/mismatched_types/similar_paths.stderr
@@ -0,0 +1,23 @@
+error[E0308]: mismatched types
+  --> $DIR/similar_paths.rs:7:5
+   |
+LL | pub fn foo() -> Option<u8> {
+   |                 ---------- expected `Option<u8>` because of return type
+LL |     Some(42_u8)
+   |     ^^^^^^^^^^^ expected enum `Option`, found enum `std::option::Option`
+   |
+   = note: enum `std::option::Option` and enum `Option` have similar names, but are actually distinct types
+note: enum `std::option::Option` is defined in crate `core`
+  --> $SRC_DIR/core/src/option.rs:LL:COL
+   |
+LL | pub enum Option<T> {
+   | ^^^^^^^^^^^^^^^^^^
+note: enum `Option` is defined in the current crate
+  --> $DIR/similar_paths.rs:1:1
+   |
+LL | enum Option<T> {
+   | ^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/mismatched_types/similar_paths_primitive.rs b/src/test/ui/mismatched_types/similar_paths_primitive.rs
new file mode 100644
index 000000000000..8f5b7cce4690
--- /dev/null
+++ b/src/test/ui/mismatched_types/similar_paths_primitive.rs
@@ -0,0 +1,10 @@
+#![allow(non_camel_case_types)]
+
+struct bool;
+
+fn foo(_: bool) {}
+
+fn main() {
+    foo(true);
+    //~^ ERROR mismatched types [E0308]
+}
diff --git a/src/test/ui/mismatched_types/similar_paths_primitive.stderr b/src/test/ui/mismatched_types/similar_paths_primitive.stderr
new file mode 100644
index 000000000000..8a2f73945e84
--- /dev/null
+++ b/src/test/ui/mismatched_types/similar_paths_primitive.stderr
@@ -0,0 +1,24 @@
+error[E0308]: mismatched types
+  --> $DIR/similar_paths_primitive.rs:8:9
+   |
+LL |     foo(true);
+   |     --- ^^^^ expected struct `bool`, found `bool`
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: bool and struct `bool` have similar names, but are actually distinct types
+   = note: bool is a primitive defined by the language
+note: struct `bool` is defined in the current crate
+  --> $DIR/similar_paths_primitive.rs:3:1
+   |
+LL | struct bool;
+   | ^^^^^^^^^^^
+note: function defined here
+  --> $DIR/similar_paths_primitive.rs:5:4
+   |
+LL | fn foo(_: bool) {}
+   |    ^^^ -------
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/modules/auxiliary/dummy_lib.rs b/src/test/ui/modules/auxiliary/dummy_lib.rs
new file mode 100644
index 000000000000..ef805c1f0203
--- /dev/null
+++ b/src/test/ui/modules/auxiliary/dummy_lib.rs
@@ -0,0 +1,2 @@
+#[allow(dead_code)]
+pub struct Dummy;
diff --git a/src/test/ui/modules/special_module_name.rs b/src/test/ui/modules/special_module_name.rs
new file mode 100644
index 000000000000..15c59b2da828
--- /dev/null
+++ b/src/test/ui/modules/special_module_name.rs
@@ -0,0 +1,8 @@
+mod lib;
+//~^ WARN found module declaration for lib.rs
+//~| ERROR file not found for module `lib`
+mod main;
+//~^ WARN found module declaration for main.rs
+//~| ERROR file not found for module `main`
+
+fn main() {}
diff --git a/src/test/ui/modules/special_module_name.stderr b/src/test/ui/modules/special_module_name.stderr
new file mode 100644
index 000000000000..8b3da29386df
--- /dev/null
+++ b/src/test/ui/modules/special_module_name.stderr
@@ -0,0 +1,37 @@
+error[E0583]: file not found for module `lib`
+  --> $DIR/special_module_name.rs:1:1
+   |
+LL | mod lib;
+   | ^^^^^^^^
+   |
+   = help: to create the module `lib`, create file "$DIR/lib.rs" or "$DIR/lib/mod.rs"
+
+error[E0583]: file not found for module `main`
+  --> $DIR/special_module_name.rs:4:1
+   |
+LL | mod main;
+   | ^^^^^^^^^
+   |
+   = help: to create the module `main`, create file "$DIR/main.rs" or "$DIR/main/mod.rs"
+
+warning: found module declaration for lib.rs
+  --> $DIR/special_module_name.rs:1:1
+   |
+LL | mod lib;
+   | ^^^^^^^^
+   |
+   = note: `#[warn(special_module_name)]` on by default
+   = note: lib.rs is the root of this crate's library target
+   = help: to refer to it from other targets, use the library's name as the path
+
+warning: found module declaration for main.rs
+  --> $DIR/special_module_name.rs:4:1
+   |
+LL | mod main;
+   | ^^^^^^^^^
+   |
+   = note: a binary crate cannot be used as library
+
+error: aborting due to 2 previous errors; 2 warnings emitted
+
+For more information about this error, try `rustc --explain E0583`.
diff --git a/src/test/ui/modules/special_module_name_ignore.rs b/src/test/ui/modules/special_module_name_ignore.rs
new file mode 100644
index 000000000000..07cea9b2b05a
--- /dev/null
+++ b/src/test/ui/modules/special_module_name_ignore.rs
@@ -0,0 +1,9 @@
+// run-pass
+
+#[path = "auxiliary/dummy_lib.rs"]
+mod lib;
+
+#[path = "auxiliary/dummy_lib.rs"]
+mod main;
+
+fn main() {}
diff --git a/src/test/ui/moves/issue-72649-uninit-in-loop.stderr b/src/test/ui/moves/issue-72649-uninit-in-loop.stderr
index c7373b5be9d8..974994223a3f 100644
--- a/src/test/ui/moves/issue-72649-uninit-in-loop.stderr
+++ b/src/test/ui/moves/issue-72649-uninit-in-loop.stderr
@@ -47,6 +47,11 @@ LL |         let value: NonCopy;
    |             ----- binding declared here but left uninitialized
 LL |         let _used = value;
    |                     ^^^^^ `value` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |         let value: NonCopy = todo!();
+   |                            +++++++++
 
 error[E0381]: used binding `value` isn't initialized
   --> $DIR/issue-72649-uninit-in-loop.rs:69:21
@@ -56,6 +61,11 @@ LL |     let mut value: NonCopy;
 LL |     loop {
 LL |         let _used = value;
    |                     ^^^^^ `value` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let mut value: NonCopy = todo!();
+   |                            +++++++++
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/moves/move-into-dead-array-1.stderr b/src/test/ui/moves/move-into-dead-array-1.stderr
index 344a6bbf0c92..6db0f0bcbffe 100644
--- a/src/test/ui/moves/move-into-dead-array-1.stderr
+++ b/src/test/ui/moves/move-into-dead-array-1.stderr
@@ -5,6 +5,11 @@ LL |     let mut a: [D; 4];
    |         ----- binding declared here but left uninitialized
 LL |     a[i] = d();
    |     ^^^^ `a` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let mut a: [D; 4] = todo!();
+   |                       +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/moves/move-of-addr-of-mut.stderr b/src/test/ui/moves/move-of-addr-of-mut.stderr
index e75f2b1c0894..ddebaa0129a4 100644
--- a/src/test/ui/moves/move-of-addr-of-mut.stderr
+++ b/src/test/ui/moves/move-of-addr-of-mut.stderr
@@ -7,6 +7,10 @@ LL |     std::ptr::addr_of_mut!(x);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^ `x` used here but it isn't initialized
    |
    = note: this error originates in the macro `std::ptr::addr_of_mut` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider assigning a value
+   |
+LL |     let mut x: S = todo!();
+   |                  +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/moves/move-out-of-array-ref.stderr b/src/test/ui/moves/move-out-of-array-ref.stderr
index fd682e56ae1d..0caa0b83a4c7 100644
--- a/src/test/ui/moves/move-out-of-array-ref.stderr
+++ b/src/test/ui/moves/move-out-of-array-ref.stderr
@@ -13,7 +13,7 @@ error[E0508]: cannot move out of type `[D; 4]`, a non-copy array
   --> $DIR/move-out-of-array-ref.rs:13:27
    |
 LL |     let [_, s @ .. , _] = *a;
-   |             ------        ^^
+   |             -             ^^
    |             |             |
    |             |             cannot move out of here
    |             |             help: consider borrowing here: `&*a`
@@ -35,7 +35,7 @@ error[E0508]: cannot move out of type `[D; 4]`, a non-copy array
   --> $DIR/move-out-of-array-ref.rs:23:27
    |
 LL |     let [_, s @ .. , _] = *a;
-   |             ------        ^^
+   |             -             ^^
    |             |             |
    |             |             cannot move out of here
    |             |             help: consider borrowing here: `&*a`
diff --git a/src/test/ui/moves/move-out-of-slice-2.stderr b/src/test/ui/moves/move-out-of-slice-2.stderr
index 9a863bf31a7f..93b0dcfc2d18 100644
--- a/src/test/ui/moves/move-out-of-slice-2.stderr
+++ b/src/test/ui/moves/move-out-of-slice-2.stderr
@@ -14,7 +14,7 @@ LL |     match *a {
    |           ^^ cannot move out of here
 LL |
 LL |         [a @ ..] => {}
-   |          ------
+   |          -
    |          |
    |          data moved here
    |          move occurs because `a` has type `[A]`, which does not implement the `Copy` trait
@@ -26,7 +26,7 @@ LL |     match *b {
    |           ^^ cannot move out of here
 LL |
 LL |         [_, _, b @ .., _] => {}
-   |                ------
+   |                -
    |                |
    |                data moved here
    |                move occurs because `b` has type `[A]`, which does not implement the `Copy` trait
@@ -38,7 +38,7 @@ LL |     match *c {
    |           ^^ cannot move out of here
 LL |
 LL |         [c @ ..] => {}
-   |          ------
+   |          -
    |          |
    |          data moved here
    |          move occurs because `c` has type `[C]`, which does not implement the `Copy` trait
@@ -50,7 +50,7 @@ LL |     match *d {
    |           ^^ cannot move out of here
 LL |
 LL |         [_, _, d @ .., _] => {}
-   |                ------
+   |                -
    |                |
    |                data moved here
    |                move occurs because `d` has type `[C]`, which does not implement the `Copy` trait
diff --git a/src/test/ui/namespace/namespace-mix.stderr b/src/test/ui/namespace/namespace-mix.stderr
index b04ea14d1a58..c07914df7273 100644
--- a/src/test/ui/namespace/namespace-mix.stderr
+++ b/src/test/ui/namespace/namespace-mix.stderr
@@ -218,7 +218,7 @@ error[E0277]: the trait bound `fn() -> c::TS {c::TS}: Impossible` is not satisfi
   --> $DIR/namespace-mix.rs:56:11
    |
 LL |     check(m3::TS);
-   |     ----- ^^^^^^ the trait `Impossible` is not implemented for `fn() -> c::TS {c::TS}`
+   |     ----- ^^^^^^ the trait `Impossible` is not implemented for fn item `fn() -> c::TS {c::TS}`
    |     |
    |     required by a bound introduced by this call
    |
@@ -274,7 +274,7 @@ error[E0277]: the trait bound `fn() -> namespace_mix::c::TS {namespace_mix::c::T
   --> $DIR/namespace-mix.rs:62:11
    |
 LL |     check(xm3::TS);
-   |     ----- ^^^^^^^ the trait `Impossible` is not implemented for `fn() -> namespace_mix::c::TS {namespace_mix::c::TS}`
+   |     ----- ^^^^^^^ the trait `Impossible` is not implemented for fn item `fn() -> namespace_mix::c::TS {namespace_mix::c::TS}`
    |     |
    |     required by a bound introduced by this call
    |
@@ -526,7 +526,7 @@ error[E0277]: the trait bound `fn() -> c::E {c::E::TV}: Impossible` is not satis
   --> $DIR/namespace-mix.rs:122:11
    |
 LL |     check(m9::TV);
-   |     ----- ^^^^^^ the trait `Impossible` is not implemented for `fn() -> c::E {c::E::TV}`
+   |     ----- ^^^^^^ the trait `Impossible` is not implemented for fn item `fn() -> c::E {c::E::TV}`
    |     |
    |     required by a bound introduced by this call
    |
@@ -582,7 +582,7 @@ error[E0277]: the trait bound `fn() -> namespace_mix::c::E {namespace_mix::xm7::
   --> $DIR/namespace-mix.rs:128:11
    |
 LL |     check(xm9::TV);
-   |     ----- ^^^^^^^ the trait `Impossible` is not implemented for `fn() -> namespace_mix::c::E {namespace_mix::xm7::TV}`
+   |     ----- ^^^^^^^ the trait `Impossible` is not implemented for fn item `fn() -> namespace_mix::c::E {namespace_mix::xm7::TV}`
    |     |
    |     required by a bound introduced by this call
    |
diff --git a/src/test/ui/never_type/fallback-closure-wrap.rs b/src/test/ui/never_type/fallback-closure-wrap.rs
index 35052da6760b..f88355bb285f 100644
--- a/src/test/ui/never_type/fallback-closure-wrap.rs
+++ b/src/test/ui/never_type/fallback-closure-wrap.rs
@@ -3,7 +3,7 @@
 //
 // This particular test case currently fails as the inference to `()` rather
 // than `!` happens as a result of an `as` cast, which is not currently tracked.
-// Crater did not find many cases of this occuring, but it is included for
+// Crater did not find many cases of this occurring, but it is included for
 // awareness.
 //
 // revisions: nofallback fallback
diff --git a/src/test/ui/never_type/issue-52443.rs b/src/test/ui/never_type/issue-52443.rs
index cebcca944af8..0498a8a16259 100644
--- a/src/test/ui/never_type/issue-52443.rs
+++ b/src/test/ui/never_type/issue-52443.rs
@@ -9,6 +9,6 @@ fn main() {
     [(); { for _ in 0usize.. {}; 0}];
     //~^ ERROR `for` is not allowed in a `const`
     //~| ERROR cannot convert
-    //~| ERROR mutable references are not allowed in constants
-    //~| ERROR cannot call non-const fn
+    //~| ERROR mutable references
+    //~| ERROR cannot call
 }
diff --git a/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr b/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr
index f86a19fff845..d2d26b23d646 100644
--- a/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr
+++ b/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr
@@ -6,7 +6,7 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
    |
    = note: defining type: test::{closure#0} with closure substs [
                i16,
-               for<'r, 's, 't0> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('t0) }) i32)),
+               for<'a, 'b, 'c> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('c) }) i32)),
                (),
            ]
 
@@ -22,14 +22,8 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
 note: no external requirements
   --> $DIR/escape-argument-callee.rs:20:1
    |
-LL | / fn test() {
-LL | |     let x = 44;
-LL | |     let mut p = &x;
-LL | |
-...  |
-LL | |     deref(p);
-LL | | }
-   | |_^
+LL | fn test() {
+   | ^^^^^^^^^
    |
    = note: defining type: test
 
diff --git a/src/test/ui/nll/closure-requirements/escape-argument.stderr b/src/test/ui/nll/closure-requirements/escape-argument.stderr
index 8cd8b43cabec..6355d3295247 100644
--- a/src/test/ui/nll/closure-requirements/escape-argument.stderr
+++ b/src/test/ui/nll/closure-requirements/escape-argument.stderr
@@ -6,21 +6,15 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
    |
    = note: defining type: test::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) i32)),
+               for<'a, 'b> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) mut &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) i32)),
                (),
            ]
 
 note: no external requirements
   --> $DIR/escape-argument.rs:20:1
    |
-LL | / fn test() {
-LL | |     let x = 44;
-LL | |     let mut p = &x;
-LL | |
-...  |
-LL | |     deref(p);
-LL | | }
-   | |_^
+LL | fn test() {
+   | ^^^^^^^^^
    |
    = note: defining type: test
 
diff --git a/src/test/ui/nll/closure-requirements/escape-upvar-nested.stderr b/src/test/ui/nll/closure-requirements/escape-upvar-nested.stderr
index abf80e039289..4fbd5eb19a56 100644
--- a/src/test/ui/nll/closure-requirements/escape-upvar-nested.stderr
+++ b/src/test/ui/nll/closure-requirements/escape-upvar-nested.stderr
@@ -29,14 +29,8 @@ LL |         let mut closure = || {
 note: no external requirements
   --> $DIR/escape-upvar-nested.rs:13:1
    |
-LL | / fn test() {
-LL | |     let x = 44;
-LL | |     let mut p = &x;
-LL | |
-...  |
-LL | |     deref(p);
-LL | | }
-   | |_^
+LL | fn test() {
+   | ^^^^^^^^^
    |
    = note: defining type: test
 
diff --git a/src/test/ui/nll/closure-requirements/escape-upvar-ref.stderr b/src/test/ui/nll/closure-requirements/escape-upvar-ref.stderr
index bc7546421731..bc1ceac5bf01 100644
--- a/src/test/ui/nll/closure-requirements/escape-upvar-ref.stderr
+++ b/src/test/ui/nll/closure-requirements/escape-upvar-ref.stderr
@@ -15,14 +15,8 @@ LL |         let mut closure = || p = &y;
 note: no external requirements
   --> $DIR/escape-upvar-ref.rs:17:1
    |
-LL | / fn test() {
-LL | |     let x = 44;
-LL | |     let mut p = &x;
-LL | |
-...  |
-LL | |     deref(p);
-LL | | }
-   | |_^
+LL | fn test() {
+   | ^^^^^^^^^
    |
    = note: defining type: test
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
index b9b0f3ad2578..5f9724ce3db1 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
@@ -6,7 +6,7 @@ LL |         |_outlives1, _outlives2, _outlives3, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&'_#2r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) &'_#3r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>)),
+               for<'a, 'b> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&'_#2r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) &'_#3r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#4r
@@ -27,14 +27,8 @@ LL |             demand_y(x, y, p)
 note: no external requirements
   --> $DIR/propagate-approximated-fail-no-postdom.rs:38:1
    |
-LL | / fn supply<'a, 'b, 'c>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>, cell_c: Cell<&'c u32>) {
-LL | |     establish_relationships(
-LL | |         cell_a,
-LL | |         cell_b,
-...  |
-LL | |     );
-LL | | }
-   | |_^
+LL | fn supply<'a, 'b, 'c>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>, cell_c: Cell<&'c u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr
index a2371ee314a7..ec728ebd5adf 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr
@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's, 't0, 't1, 't2, 't3> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('t0) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) &'_#2r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('t2) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrNamed('t3) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) u32>)),
+               for<'a, 'b, 'c, 'd, 'e, 'f> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('c) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) &'_#2r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('e) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrNamed('f) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#3r
@@ -17,14 +17,8 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
 note: no external requirements
   --> $DIR/propagate-approximated-ref.rs:42:1
    |
-LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-LL | |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-LL | |         // Only works if 'x: 'y:
-LL | |         demand_y(x, y, x.get())
-LL | |
-LL | |     });
-LL | | }
-   | |_^
+LL | fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
index e53ae167f12d..01293379700d 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
@@ -6,7 +6,7 @@ LL |     foo(cell, |cell_a, cell_x| {
    |
    = note: defining type: case1::{closure#0} with closure substs [
                i32,
-               for<'r> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>)),
+               for<'a> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>)),
                (),
            ]
 
@@ -23,14 +23,8 @@ LL |         cell_a.set(cell_x.get()); // forces 'x: 'a, error in closure
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-comparing-against-free.rs:18:1
    |
-LL | / fn case1() {
-LL | |     let a = 0;
-LL | |     let cell = Cell::new(&a);
-LL | |     foo(cell, |cell_a, cell_x| {
-...  |
-LL | |     })
-LL | | }
-   | |_^
+LL | fn case1() {
+   | ^^^^^^^^^^
    |
    = note: defining type: case1
 
@@ -42,7 +36,7 @@ LL |     foo(cell, |cell_a, cell_x| {
    |
    = note: defining type: case2::{closure#0} with closure substs [
                i32,
-               for<'r> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>)),
+               for<'a> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>)),
                (),
            ]
    = note: number of external vids: 2
@@ -51,14 +45,8 @@ LL |     foo(cell, |cell_a, cell_x| {
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-comparing-against-free.rs:28:1
    |
-LL | / fn case2() {
-LL | |     let a = 0;
-LL | |     let cell = Cell::new(&a);
-LL | |
-...  |
-LL | |     })
-LL | | }
-   | |_^
+LL | fn case2() {
+   | ^^^^^^^^^^
    |
    = note: defining type: case2
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
index c3c7eb1bd9e5..ce85b20b344e 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's, 't0, 't1, 't2> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('t0) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('t2) }) u32>)),
+               for<'a, 'b, 'c, 'd, 'e> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('c) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('e) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#2r
@@ -17,14 +17,8 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:31:1
    |
-LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-LL | |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-LL | |
-LL | |
-...  |
-LL | |     });
-LL | | }
-   | |_^
+LL | fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
@@ -46,7 +40,7 @@ LL | |     });
    | |______`cell_a` escapes the function body here
    |        argument requires that `'a` must outlive `'static`
    |
-   = note: requirement occurs because of the type `Cell<&'_#10r u32>`, which makes the generic argument `&'_#10r u32` invariant
+   = note: requirement occurs because of the type `Cell<&'_#9r u32>`, which makes the generic argument `&'_#9r u32` invariant
    = note: the struct `Cell<T>` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
index 846e5aedb3e7..20c7967b78bc 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's, 't0, 't1, 't2, 't3> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('t0) }) std::cell::Cell<&'_#2r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('t2) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrNamed('t3) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) u32>)),
+               for<'a, 'b, 'c, 'd, 'e, 'f> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('c) }) std::cell::Cell<&'_#2r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('e) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrNamed('f) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#3r
@@ -17,14 +17,8 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:34:1
    |
-LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-LL | |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-LL | |
-LL | |
-...  |
-LL | |     });
-LL | | }
-   | |_^
+LL | fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
@@ -46,7 +40,7 @@ LL | |     });
    | |______`cell_a` escapes the function body here
    |        argument requires that `'a` must outlive `'static`
    |
-   = note: requirement occurs because of the type `Cell<&'_#11r u32>`, which makes the generic argument `&'_#11r u32` invariant
+   = note: requirement occurs because of the type `Cell<&'_#10r u32>`, which makes the generic argument `&'_#10r u32` invariant
    = note: the struct `Cell<T>` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr
index a570932eda9a..f7db5ab1f27a 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr
@@ -6,7 +6,7 @@ LL |     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
    |
    = note: defining type: test::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) &'_#2r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>)),
+               for<'a, 'b> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) &'_#2r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#3r
@@ -17,14 +17,8 @@ LL |     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
 note: no external requirements
   --> $DIR/propagate-approximated-val.rs:35:1
    |
-LL | / fn test<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-LL | |     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
-LL | |         // Only works if 'x: 'y:
-LL | |         demand_y(outlives1, outlives2, x.get())
-LL | |
-LL | |     });
-LL | | }
-   | |_^
+LL | fn test<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: test
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr b/src/test/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr
index 407bc6764d6d..3488edc75e10 100644
--- a/src/test/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr
@@ -6,7 +6,7 @@ LL |         |_outlives1, _outlives2, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) &'_#2r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>)),
+               for<'a, 'b> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) &'_#2r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#3r
@@ -16,14 +16,8 @@ LL |         |_outlives1, _outlives2, x, y| {
 note: no external requirements
   --> $DIR/propagate-despite-same-free-region.rs:39:1
    |
-LL | / fn supply<'a>(cell_a: Cell<&'a u32>) {
-LL | |     establish_relationships(
-LL | |         cell_a,
-LL | |         |_outlives1, _outlives2, x, y| {
-...  |
-LL | |     );
-LL | | }
-   | |_^
+LL | fn supply<'a>(cell_a: Cell<&'a u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
index fcb55d37f310..0dc2d0de98fe 100644
--- a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's, 't0, 't1, 't2> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) &'_#1r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('t0) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('t2) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>)),
+               for<'a, 'b, 'c, 'd, 'e> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) &'_#1r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('c) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('e) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#2r
@@ -26,14 +26,8 @@ LL |         demand_y(x, y, x.get())
 note: no external requirements
   --> $DIR/propagate-fail-to-approximate-longer-no-bounds.rs:34:1
    |
-LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-LL | |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-LL | |         // Only works if 'x: 'y:
-LL | |         demand_y(x, y, x.get())
-LL | |
-LL | |     });
-LL | | }
-   | |_^
+LL | fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
index 75beae39e231..4c9e026ea522 100644
--- a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
@@ -6,7 +6,7 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<'r, 's, 't0, 't1, 't2, 't3> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) &'_#1r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('t0) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) &'_#2r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('t2) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrNamed('t3) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('t1) }) u32>)),
+               for<'a, 'b, 'c, 'd, 'e, 'f> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) &'_#1r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrNamed('c) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) &'_#2r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrNamed('e) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrNamed('f) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrNamed('d) }) u32>)),
                (),
            ]
    = note: late-bound region is '_#3r
@@ -26,14 +26,8 @@ LL |         demand_y(x, y, x.get())
 note: no external requirements
   --> $DIR/propagate-fail-to-approximate-longer-wrong-bounds.rs:38:1
    |
-LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
-LL | |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-LL | |         // Only works if 'x: 'y:
-LL | |         demand_y(x, y, x.get())
-LL | |
-LL | |     });
-LL | | }
-   | |_^
+LL | fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: supply
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-from-trait-match.stderr b/src/test/ui/nll/closure-requirements/propagate-from-trait-match.stderr
index 58aced2bfcdb..750b08bbe855 100644
--- a/src/test/ui/nll/closure-requirements/propagate-from-trait-match.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-from-trait-match.stderr
@@ -18,11 +18,7 @@ note: no external requirements
 LL | / fn supply<'a, T>(value: T)
 LL | | where
 LL | |     T: Trait<'a>,
-LL | | {
-...  |
-LL | |     });
-LL | | }
-   | |_^
+   | |_________________^
    |
    = note: defining type: supply::<'_#1r, T>
 
diff --git a/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr b/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr
index 1c9d0c835494..68429142edec 100644
--- a/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr
+++ b/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr
@@ -6,7 +6,7 @@ LL |     expect_sig(|a, b| b); // ought to return `a`
    |
    = note: defining type: test::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) i32)) -> &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) i32,
+               for<'a, 'b> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) i32, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) i32)) -> &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) i32,
                (),
            ]
 
@@ -22,11 +22,8 @@ LL |     expect_sig(|a, b| b); // ought to return `a`
 note: no external requirements
   --> $DIR/return-wrong-bound-region.rs:10:1
    |
-LL | / fn test() {
-LL | |     expect_sig(|a, b| b); // ought to return `a`
-LL | |
-LL | | }
-   | |_^
+LL | fn test() {
+   | ^^^^^^^^^
    |
    = note: defining type: test
 
diff --git a/src/test/ui/nll/issue-21232-partial-init-and-use.rs b/src/test/ui/nll/issue-21232-partial-init-and-use.rs
index 4cd1e406f944..ad3eb248351d 100644
--- a/src/test/ui/nll/issue-21232-partial-init-and-use.rs
+++ b/src/test/ui/nll/issue-21232-partial-init-and-use.rs
@@ -53,7 +53,7 @@ impl<F> R<F> { fn new(f: F) -> Self { R { w: 0, f } } }
 // * local/field: Is the structure in a local or a field
 // * fully/partial/void: Are we fully initializing it before using any part?
 //                       Is whole type empty due to a void component?
-// * init/reinit: First initialization, or did we previously inititalize and then move out?
+// * init/reinit: First initialization, or did we previously initialize and then move out?
 // * struct/tuple: Is this a struct or a (X, Y).
 //
 // As a shorthand for the cases above, adding a numeric summary to
diff --git a/src/test/ui/nll/issue-51244.stderr b/src/test/ui/nll/issue-51244.stderr
index 19f0223a357a..dcb6f9fec18b 100644
--- a/src/test/ui/nll/issue-51244.stderr
+++ b/src/test/ui/nll/issue-51244.stderr
@@ -2,7 +2,7 @@ error[E0594]: cannot assign to `*my_ref`, which is behind a `&` reference
   --> $DIR/issue-51244.rs:3:5
    |
 LL |     let ref my_ref @ _ = 0;
-   |         -------------- help: consider changing this to be a mutable reference: `ref mut my_ref @ _`
+   |         ---------- help: consider changing this to be a mutable reference: `ref mut my_ref`
 LL |     *my_ref = 0;
    |     ^^^^^^^^^^^ `my_ref` is a `&` reference, so the data it refers to cannot be written
 
diff --git a/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr b/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr
index 0ae6b7c1d7f0..6e96f40c0e0d 100644
--- a/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr
+++ b/src/test/ui/nll/issue-57642-higher-ranked-subtype.stderr
@@ -1,11 +1,11 @@
-error[E0599]: the function or associated item `make_g` exists for fn pointer `for<'r> fn(&'r ())`, but its trait bounds were not satisfied
+error[E0599]: the function or associated item `make_g` exists for fn pointer `for<'a> fn(&'a ())`, but its trait bounds were not satisfied
   --> $DIR/issue-57642-higher-ranked-subtype.rs:31:25
    |
 LL |     let x = <fn (&())>::make_g();
-   |                         ^^^^^^ function or associated item cannot be called on `for<'r> fn(&'r ())` due to unsatisfied trait bounds
+   |                         ^^^^^^ function or associated item cannot be called on `for<'a> fn(&'a ())` due to unsatisfied trait bounds
    |
    = note: the following trait bounds were not satisfied:
-           `for<'r> fn(&'r ()): X`
+           `for<'a> fn(&'a ()): X`
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `X` defines an item `make_g`, perhaps you need to implement it
   --> $DIR/issue-57642-higher-ranked-subtype.rs:4:1
@@ -13,11 +13,11 @@ note: `X` defines an item `make_g`, perhaps you need to implement it
 LL | trait X {
    | ^^^^^^^
 
-error[E0599]: no function or associated item named `make_f` found for fn pointer `for<'r> fn(&'r ())` in the current scope
+error[E0599]: no function or associated item named `make_f` found for fn pointer `for<'a> fn(&'a ())` in the current scope
   --> $DIR/issue-57642-higher-ranked-subtype.rs:35:25
    |
 LL |     let x = <fn (&())>::make_f();
-   |                         ^^^^^^ function or associated item not found in `for<'r> fn(&'r ())`
+   |                         ^^^^^^ function or associated item not found in `for<'a> fn(&'a ())`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `Y` defines an item `make_f`, perhaps you need to implement it
diff --git a/src/test/ui/nll/issue-97997.stderr b/src/test/ui/nll/issue-97997.stderr
index 78401bbf6540..46440c021f54 100644
--- a/src/test/ui/nll/issue-97997.stderr
+++ b/src/test/ui/nll/issue-97997.stderr
@@ -4,7 +4,7 @@ error: implementation of `Foo` is not general enough
 LL |     <fn(&u8) as Foo>::ASSOC;
    |     ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Foo` is not general enough
    |
-   = note: `Foo` would have to be implemented for the type `for<'r> fn(&'r u8)`
+   = note: `Foo` would have to be implemented for the type `for<'a> fn(&'a u8)`
    = note: ...but `Foo` is actually implemented for the type `fn(&'0 u8)`, for some specific lifetime `'0`
 
 error: implementation of `Foo` is not general enough
@@ -13,7 +13,7 @@ error: implementation of `Foo` is not general enough
 LL |     <fn(&u8) as Foo>::ASSOC;
    |     ^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Foo` is not general enough
    |
-   = note: `Foo` would have to be implemented for the type `for<'r> fn(&'r u8)`
+   = note: `Foo` would have to be implemented for the type `for<'a> fn(&'a u8)`
    = note: ...but `Foo` is actually implemented for the type `fn(&'0 u8)`, for some specific lifetime `'0`
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/nll/local-outlives-static-via-hrtb.stderr b/src/test/ui/nll/local-outlives-static-via-hrtb.stderr
index 61009da49ffe..f5c10f3ddea0 100644
--- a/src/test/ui/nll/local-outlives-static-via-hrtb.stderr
+++ b/src/test/ui/nll/local-outlives-static-via-hrtb.stderr
@@ -9,6 +9,12 @@ LL |     assert_static_via_hrtb(&local);
 LL |     assert_static_via_hrtb_with_assoc_type(&&local);
 LL | }
    | - `local` dropped here while still borrowed
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/local-outlives-static-via-hrtb.rs:15:53
+   |
+LL | fn assert_static_via_hrtb<G>(_: G) where for<'a> G: Outlives<'a> {}
+   |                                                     ^^^^^^^^^^^^
 
 error[E0597]: `local` does not live long enough
   --> $DIR/local-outlives-static-via-hrtb.rs:25:45
@@ -20,6 +26,12 @@ LL |     assert_static_via_hrtb_with_assoc_type(&&local);
    |     argument requires that `local` is borrowed for `'static`
 LL | }
    | - `local` dropped here while still borrowed
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/local-outlives-static-via-hrtb.rs:19:20
+   |
+LL |     for<'a> &'a T: Reference<AssociatedType = &'a ()>,
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/nll/match-cfg-fake-edges.stderr b/src/test/ui/nll/match-cfg-fake-edges.stderr
index 250aa482e5c6..2d48a914218f 100644
--- a/src/test/ui/nll/match-cfg-fake-edges.stderr
+++ b/src/test/ui/nll/match-cfg-fake-edges.stderr
@@ -9,6 +9,11 @@ LL |         _ if { x = 2; true } => 1,
 LL |         _ if {
 LL |             x;
    |             ^ `x` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let x = 0;
+   |           +++
 
 error[E0382]: use of moved value: `x`
   --> $DIR/match-cfg-fake-edges.rs:35:13
diff --git a/src/test/ui/nll/match-on-borrowed.stderr b/src/test/ui/nll/match-on-borrowed.stderr
index 664f36f695cf..32666529f3f9 100644
--- a/src/test/ui/nll/match-on-borrowed.stderr
+++ b/src/test/ui/nll/match-on-borrowed.stderr
@@ -40,6 +40,11 @@ LL |     let n: Never;
    |         - binding declared here but left uninitialized
 LL |     match n {}
    |           ^ `n` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let n: Never = todo!();
+   |                  +++++++++
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/nll/polonius/assignment-kills-loans.rs b/src/test/ui/nll/polonius/assignment-kills-loans.rs
index c4cf20389ac8..696bf61cefde 100644
--- a/src/test/ui/nll/polonius/assignment-kills-loans.rs
+++ b/src/test/ui/nll/polonius/assignment-kills-loans.rs
@@ -1,7 +1,7 @@
 #![allow(dead_code)]
 
 // This tests the various kinds of assignments there are. Polonius used to generate `killed`
-// facts only on simple assigments, but not projections, incorrectly causing errors to be emitted
+// facts only on simple assignments, but not projections, incorrectly causing errors to be emitted
 // for code accepted by NLL. They are all variations from example code in the NLL RFC.
 
 // check-pass
diff --git a/src/test/ui/nll/relate_tys/impl-fn-ignore-binder-via-bottom.stderr b/src/test/ui/nll/relate_tys/impl-fn-ignore-binder-via-bottom.stderr
index 8c47379886d2..b945ffedda5a 100644
--- a/src/test/ui/nll/relate_tys/impl-fn-ignore-binder-via-bottom.stderr
+++ b/src/test/ui/nll/relate_tys/impl-fn-ignore-binder-via-bottom.stderr
@@ -4,7 +4,7 @@ error: implementation of `Y` is not general enough
 LL |     let _x = <fn(&())>::make_f();
    |              ^^^^^^^^^^^^^^^^^^^ implementation of `Y` is not general enough
    |
-   = note: `Y` would have to be implemented for the type `for<'r> fn(&'r ())`
+   = note: `Y` would have to be implemented for the type `for<'a> fn(&'a ())`
    = note: ...but `Y` is actually implemented for the type `fn(&'0 ())`, for some specific lifetime `'0`
 
 error: implementation of `Y` is not general enough
@@ -13,7 +13,7 @@ error: implementation of `Y` is not general enough
 LL |     let _x = <fn(&())>::make_f();
    |              ^^^^^^^^^^^^^^^^^^^ implementation of `Y` is not general enough
    |
-   = note: `Y` would have to be implemented for the type `for<'r> fn(&'r ())`
+   = note: `Y` would have to be implemented for the type `for<'a> fn(&'a ())`
    = note: ...but `Y` is actually implemented for the type `fn(&'0 ())`, for some specific lifetime `'0`
 
 error: implementation of `Y` is not general enough
@@ -22,7 +22,7 @@ error: implementation of `Y` is not general enough
 LL |     let _x = <fn(&())>::make_f();
    |              ^^^^^^^^^^^^^^^^^^^ implementation of `Y` is not general enough
    |
-   = note: `Y` would have to be implemented for the type `for<'r> fn(&'r ())`
+   = note: `Y` would have to be implemented for the type `for<'a> fn(&'a ())`
    = note: ...but `Y` is actually implemented for the type `fn(&'0 ())`, for some specific lifetime `'0`
 
 error: aborting due to 3 previous errors
diff --git a/src/test/ui/nll/relate_tys/universe-violation.stderr b/src/test/ui/nll/relate_tys/universe-violation.stderr
index 6f38154e3792..fe801b42c0a4 100644
--- a/src/test/ui/nll/relate_tys/universe-violation.stderr
+++ b/src/test/ui/nll/relate_tys/universe-violation.stderr
@@ -4,7 +4,7 @@ error[E0308]: mismatched types
 LL |     let b: fn(&u32) -> &u32 = a;
    |                               ^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'r> fn(&'r u32) -> &'r u32`
+   = note: expected fn pointer `for<'a> fn(&'a u32) -> &'a u32`
               found fn pointer `fn(&u32) -> &u32`
 
 error: aborting due to previous error
diff --git a/src/test/ui/nll/ty-outlives/projection-no-regions-closure.stderr b/src/test/ui/nll/ty-outlives/projection-no-regions-closure.stderr
index feab2476970a..ee1f7b64bb23 100644
--- a/src/test/ui/nll/ty-outlives/projection-no-regions-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-no-regions-closure.stderr
@@ -18,11 +18,7 @@ note: no external requirements
 LL | / fn no_region<'a, T>(x: Box<T>) -> Box<dyn Anything + 'a>
 LL | | where
 LL | |     T: Iterator,
-LL | | {
-LL | |     with_signature(x, |mut y| Box::new(y.next()))
-LL | |
-LL | | }
-   | |_^
+   | |________________^
    |
    = note: defining type: no_region::<'_#1r, T>
 
@@ -55,10 +51,7 @@ note: no external requirements
 LL | / fn correct_region<'a, T>(x: Box<T>) -> Box<dyn Anything + 'a>
 LL | | where
 LL | |     T: 'a + Iterator,
-LL | | {
-LL | |     with_signature(x, |mut y| Box::new(y.next()))
-LL | | }
-   | |_^
+   | |_____________________^
    |
    = note: defining type: correct_region::<'_#1r, T>
 
@@ -82,11 +75,7 @@ note: no external requirements
 LL | / fn wrong_region<'a, 'b, T>(x: Box<T>) -> Box<dyn Anything + 'a>
 LL | | where
 LL | |     T: 'b + Iterator,
-LL | | {
-LL | |     with_signature(x, |mut y| Box::new(y.next()))
-LL | |
-LL | | }
-   | |_^
+   | |_____________________^
    |
    = note: defining type: wrong_region::<'_#1r, '_#2r, T>
 
@@ -120,10 +109,7 @@ LL | / fn outlives_region<'a, 'b, T>(x: Box<T>) -> Box<dyn Anything + 'a>
 LL | | where
 LL | |     T: 'b + Iterator,
 LL | |     'b: 'a,
-LL | | {
-LL | |     with_signature(x, |mut y| Box::new(y.next()))
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: outlives_region::<'_#1r, '_#2r, T>
 
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
index 98063bd0a767..4e57dfad794e 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
@@ -20,11 +20,7 @@ note: no external requirements
 LL | / fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
-LL | | {
-...  |
-LL | |
-LL | | }
-   | |_^
+   | |____________________^
    |
    = note: defining type: no_relationships_late::<'_#1r, T>
 
@@ -74,10 +70,7 @@ LL | / fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
-...  |
-LL | |
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>
 
@@ -126,10 +119,7 @@ LL | / fn projection_outlives<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |_____________________^
    |
    = note: defining type: projection_outlives::<'_#1r, '_#2r, T>
 
@@ -155,10 +145,8 @@ LL | / fn elements_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     T: 'a,
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+LL | |     'b: 'a,
+   | |___________^
    |
    = note: defining type: elements_outlive::<'_#1r, '_#2r, T>
 
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
index 45e61bcbda85..250c796e2c71 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
@@ -19,11 +19,7 @@ note: no external requirements
 LL | / fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | |
-LL | | }
-   | |_^
+   | |____________________^
    |
    = note: defining type: no_relationships_late::<'_#1r, T>
 
@@ -61,10 +57,7 @@ LL | / fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
-...  |
-LL | |
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>
 
@@ -102,10 +95,7 @@ LL | / fn projection_outlives<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |_____________________^
    |
    = note: defining type: projection_outlives::<'_#1r, '_#2r, T>
 
@@ -130,10 +120,7 @@ LL | / fn elements_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'b: 'a,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: elements_outlive::<'_#1r, '_#2r, T>
 
@@ -157,11 +144,7 @@ note: no external requirements
 LL | / fn one_region<'a, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'a>,
-LL | | {
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |____________________^
    |
    = note: defining type: one_region::<'_#1r, T>
 
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr
index f2549205b812..b27186b05373 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr
@@ -17,10 +17,7 @@ note: no external requirements
 LL | / fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |____________________^
    |
    = note: defining type: no_relationships_late::<'_#1r, T>
 
@@ -43,10 +40,7 @@ LL | / fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>
 
@@ -69,10 +63,7 @@ LL | / fn projection_outlives<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |_____________________^
    |
    = note: defining type: projection_outlives::<'_#1r, '_#2r, T>
 
@@ -95,10 +86,7 @@ LL | / fn elements_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'b: 'a,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: elements_outlive::<'_#1r, '_#2r, T>
 
@@ -120,11 +108,7 @@ note: no external requirements
 LL | / fn one_region<'a, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'a>,
-LL | | {
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |____________________^
    |
    = note: defining type: one_region::<'_#1r, T>
 
diff --git a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
index 8e1b6fa2e463..0195a693e5ff 100644
--- a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
@@ -19,11 +19,7 @@ note: no external requirements
 LL | / fn no_relationships_late<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'c>,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | |
-LL | | }
-   | |_^
+   | |________________________^
    |
    = note: defining type: no_relationships_late::<'_#1r, '_#2r, T>
 
@@ -57,10 +53,7 @@ LL | / fn no_relationships_early<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'c>,
 LL | |     'a: 'a,
-...  |
-LL | |
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: no_relationships_early::<'_#1r, '_#2r, '_#3r, T>
 
@@ -94,10 +87,7 @@ LL | / fn projection_outlives<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'c>,
 LL | |     T::AssocType: 'a,
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |_____________________^
    |
    = note: defining type: projection_outlives::<'_#1r, '_#2r, '_#3r, T>
 
@@ -122,10 +112,7 @@ LL | / fn elements_outlive1<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'c>,
 LL | |     'b: 'a,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: elements_outlive1::<'_#1r, '_#2r, '_#3r, T>
 
@@ -150,10 +137,7 @@ LL | / fn elements_outlive2<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'c>,
 LL | |     'c: 'a,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: elements_outlive2::<'_#1r, '_#2r, '_#3r, T>
 
@@ -178,11 +162,7 @@ note: no external requirements
 LL | / fn two_regions<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'b>,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | |
-LL | | }
-   | |_^
+   | |________________________^
    |
    = note: defining type: two_regions::<'_#1r, T>
 
@@ -220,10 +200,7 @@ LL | / fn two_regions_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'b, 'b>,
 LL | |     'b: 'a,
-LL | | {
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: two_regions_outlive::<'_#1r, '_#2r, T>
 
@@ -247,11 +224,7 @@ note: no external requirements
 LL | / fn one_region<'a, T>(cell: Cell<&'a ()>, t: T)
 LL | | where
 LL | |     T: Anything<'a, 'a>,
-LL | | {
-...  |
-LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | | }
-   | |_^
+   | |________________________^
    |
    = note: defining type: one_region::<'_#1r, T>
 
diff --git a/src/test/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr b/src/test/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr
index 12c76d198e78..61c7d2550caa 100644
--- a/src/test/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr
+++ b/src/test/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr
@@ -6,7 +6,7 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
    |
    = note: defining type: generic::<T>::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) T)),
+               for<'a, 'b> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) T)),
                (),
            ]
    = note: number of external vids: 2
@@ -15,11 +15,8 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
 note: no external requirements
   --> $DIR/ty-param-closure-approximate-lower-bound.rs:22:1
    |
-LL | / fn generic<T>(value: T) {
-LL | |     let cell = Cell::new(&());
-LL | |     twice(cell, value, |a, b| invoke(a, b));
-LL | | }
-   | |_^
+LL | fn generic<T>(value: T) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: generic::<T>
 
@@ -31,7 +28,7 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
    |
    = note: defining type: generic_fail::<T>::{closure#0} with closure substs [
                i16,
-               for<'r, 's> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('r) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('s) }) T)),
+               for<'a, 'b> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed('a) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed('b) }) T)),
                (),
            ]
    = note: late-bound region is '_#2r
@@ -41,11 +38,8 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
 note: no external requirements
   --> $DIR/ty-param-closure-approximate-lower-bound.rs:28:1
    |
-LL | / fn generic_fail<'a, T>(cell: Cell<&'a ()>, value: T) {
-LL | |     twice(cell, value, |a, b| invoke(a, b));
-LL | |
-LL | | }
-   | |_^
+LL | fn generic_fail<'a, T>(cell: Cell<&'a ()>, value: T) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: generic_fail::<T>
 
diff --git a/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr b/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr
index 35741859dffe..50d9e3aabe2d 100644
--- a/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr
+++ b/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr
@@ -18,11 +18,7 @@ note: no external requirements
 LL | / fn no_region<'a, T>(x: Box<T>) -> Box<dyn Debug + 'a>
 LL | | where
 LL | |     T: Debug,
-LL | | {
-...  |
-LL | |
-LL | | }
-   | |_^
+   | |_____________^
    |
    = note: defining type: no_region::<'_#1r, T>
 
diff --git a/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr b/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr
index 0261bc39e712..14c55e32a3eb 100644
--- a/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr
+++ b/src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr
@@ -16,14 +16,8 @@ LL |     with_signature(a, b, |x, y| {
 note: no external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:26:1
    |
-LL | / fn no_region<'a, T>(a: Cell<&'a ()>, b: T) {
-LL | |     with_signature(a, b, |x, y| {
-LL | |
-LL | |         //
-...  |
-LL | |     })
-LL | | }
-   | |_^
+LL | fn no_region<'a, T>(a: Cell<&'a ()>, b: T) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: defining type: no_region::<T>
 
@@ -65,11 +59,7 @@ note: no external requirements
 LL | / fn correct_region<'a, T>(a: Cell<&'a ()>, b: T)
 LL | | where
 LL | |     T: 'a,
-LL | | {
-...  |
-LL | |     })
-LL | | }
-   | |_^
+   | |__________^
    |
    = note: defining type: correct_region::<'_#1r, T>
 
@@ -94,11 +84,7 @@ note: no external requirements
 LL | / fn wrong_region<'a, 'b, T>(a: Cell<&'a ()>, b: T)
 LL | | where
 LL | |     T: 'b,
-LL | | {
-...  |
-LL | |     })
-LL | | }
-   | |_^
+   | |__________^
    |
    = note: defining type: wrong_region::<'_#1r, T>
 
@@ -139,10 +125,7 @@ LL | / fn outlives_region<'a, 'b, T>(a: Cell<&'a ()>, b: T)
 LL | | where
 LL | |     T: 'b,
 LL | |     'b: 'a,
-...  |
-LL | |     })
-LL | | }
-   | |_^
+   | |___________^
    |
    = note: defining type: outlives_region::<'_#1r, '_#2r, T>
 
diff --git a/src/test/ui/nll/type-test-universe.stderr b/src/test/ui/nll/type-test-universe.stderr
index 242486c360a8..31e17d64b8ca 100644
--- a/src/test/ui/nll/type-test-universe.stderr
+++ b/src/test/ui/nll/type-test-universe.stderr
@@ -11,6 +11,12 @@ LL | fn test2<'a>() {
    |          -- lifetime `'a` defined here
 LL |     outlives_forall::<Value<'a>>();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/type-test-universe.rs:6:16
+   |
+LL |     for<'u> T: 'u,
+   |                ^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/adt-nullary-enums.stderr b/src/test/ui/nll/user-annotations/adt-nullary-enums.stderr
index ee332278c30f..3326fa521fc9 100644
--- a/src/test/ui/nll/user-annotations/adt-nullary-enums.stderr
+++ b/src/test/ui/nll/user-annotations/adt-nullary-enums.stderr
@@ -30,14 +30,15 @@ error[E0597]: `c` does not live long enough
    |
 LL | fn annot_reference_named_lifetime_in_closure<'a>(_: &'a u32) {
    |                                              -- lifetime `'a` defined here
-LL |     let _closure = || {
-   |                     - `c` dropped here while still borrowed
 ...
 LL |             SomeEnum::SomeVariant(Cell::new(&c)),
    |                                   ----------^^-
    |                                   |         |
    |                                   |         borrowed value does not live long enough
    |                                   argument requires that `c` is borrowed for `'a`
+...
+LL |     };
+   |     - `c` dropped here while still borrowed
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/adt-tuple-struct-calls.stderr b/src/test/ui/nll/user-annotations/adt-tuple-struct-calls.stderr
index 95bbd62c4fb0..9664fb9f5483 100644
--- a/src/test/ui/nll/user-annotations/adt-tuple-struct-calls.stderr
+++ b/src/test/ui/nll/user-annotations/adt-tuple-struct-calls.stderr
@@ -28,28 +28,28 @@ error[E0597]: `c` does not live long enough
    |
 LL | fn annot_reference_named_lifetime_in_closure<'a>(_: &'a u32) {
    |                                              -- lifetime `'a` defined here
-LL |     let _closure = || {
-   |                     - `c` dropped here while still borrowed
 ...
 LL |         f(&c);
    |         --^^-
    |         | |
    |         | borrowed value does not live long enough
    |         argument requires that `c` is borrowed for `'a`
+LL |     };
+   |     - `c` dropped here while still borrowed
 
 error[E0597]: `c` does not live long enough
   --> $DIR/adt-tuple-struct-calls.rs:53:11
    |
 LL |     let f = SomeStruct::<&'a u32>;
    |         - lifetime `'1` appears in the type of `f`
-LL |     let _closure = || {
-   |                     - `c` dropped here while still borrowed
-LL |         let c = 66;
+...
 LL |         f(&c);
    |         --^^-
    |         | |
    |         | borrowed value does not live long enough
    |         argument requires that `c` is borrowed for `'1`
+LL |     };
+   |     - `c` dropped here while still borrowed
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/fns.stderr b/src/test/ui/nll/user-annotations/fns.stderr
index bd4d121d5691..e0640da39e2b 100644
--- a/src/test/ui/nll/user-annotations/fns.stderr
+++ b/src/test/ui/nll/user-annotations/fns.stderr
@@ -28,14 +28,14 @@ error[E0597]: `c` does not live long enough
    |
 LL | fn annot_reference_named_lifetime_in_closure<'a>(_: &'a u32) {
    |                                              -- lifetime `'a` defined here
-LL |     let _closure = || {
-   |                     - `c` dropped here while still borrowed
-LL |         let c = 66;
+...
 LL |         some_fn::<&'a u32>(&c);
    |         -------------------^^-
    |         |                  |
    |         |                  borrowed value does not live long enough
    |         argument requires that `c` is borrowed for `'a`
+LL |     };
+   |     - `c` dropped here while still borrowed
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/method-call.stderr b/src/test/ui/nll/user-annotations/method-call.stderr
index fcaeb465d140..10447e45a6d4 100644
--- a/src/test/ui/nll/user-annotations/method-call.stderr
+++ b/src/test/ui/nll/user-annotations/method-call.stderr
@@ -29,14 +29,13 @@ error[E0597]: `c` does not live long enough
 LL | fn annot_reference_named_lifetime_in_closure<'a>(_: &'a u32) {
    |                                              -- lifetime `'a` defined here
 ...
-LL |     let _closure = || {
-   |                     - `c` dropped here while still borrowed
-LL |         let c = 66;
 LL |         a.method::<&'a u32>(b,  &c);
    |         ------------------------^^-
    |         |                       |
    |         |                       borrowed value does not live long enough
    |         argument requires that `c` is borrowed for `'a`
+LL |     };
+   |     - `c` dropped here while still borrowed
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-3.stderr b/src/test/ui/nll/user-annotations/method-ufcs-3.stderr
index 328dde9805aa..e7851833e93b 100644
--- a/src/test/ui/nll/user-annotations/method-ufcs-3.stderr
+++ b/src/test/ui/nll/user-annotations/method-ufcs-3.stderr
@@ -29,14 +29,13 @@ error[E0597]: `c` does not live long enough
 LL | fn annot_reference_named_lifetime_in_closure<'a>(_: &'a u32) {
    |                                              -- lifetime `'a` defined here
 ...
-LL |     let _closure = || {
-   |                     - `c` dropped here while still borrowed
-LL |         let c = 66;
 LL |         <_ as Bazoom<_>>::method::<&'a u32>(&a, b, &c);
    |         -------------------------------------------^^-
    |         |                                          |
    |         |                                          borrowed value does not live long enough
    |         argument requires that `c` is borrowed for `'a`
+LL |     };
+   |     - `c` dropped here while still borrowed
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/not-enough-arguments.stderr b/src/test/ui/not-enough-arguments.stderr
index b1df578ea80a..8b2dafb4e1d0 100644
--- a/src/test/ui/not-enough-arguments.stderr
+++ b/src/test/ui/not-enough-arguments.stderr
@@ -12,7 +12,7 @@ LL | fn foo(a: isize, b: isize, c: isize, d:isize) {
 help: provide the argument
    |
 LL |   foo(1, 2, 3, /* isize */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~
+   |      ~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 6 arguments but 3 arguments were supplied
   --> $DIR/not-enough-arguments.rs:29:3
@@ -40,7 +40,7 @@ LL |     f: i32,
 help: provide the arguments
    |
 LL |   bar(1, 2, 3, /* i32 */, /* i32 */, /* i32 */);
-   |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/numbers-arithmetic/next-power-of-two-overflow-debug.rs b/src/test/ui/numbers-arithmetic/next-power-of-two-overflow-debug.rs
index f857d4f4c7f2..79d78da3328a 100644
--- a/src/test/ui/numbers-arithmetic/next-power-of-two-overflow-debug.rs
+++ b/src/test/ui/numbers-arithmetic/next-power-of-two-overflow-debug.rs
@@ -1,7 +1,6 @@
 // run-pass
 // compile-flags: -C debug_assertions=yes
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // ignore-emscripten dies with an LLVM error
 
 use std::panic;
diff --git a/src/test/ui/object-lifetime/object-lifetime-default.rs b/src/test/ui/object-lifetime/object-lifetime-default.rs
index 60b6629e694d..74f5bb7ddb0e 100644
--- a/src/test/ui/object-lifetime/object-lifetime-default.rs
+++ b/src/test/ui/object-lifetime/object-lifetime-default.rs
@@ -1,24 +1,50 @@
 #![feature(rustc_attrs)]
 
 #[rustc_object_lifetime_default]
-struct A<T>(T); //~ ERROR BaseDefault
+struct A<
+    T, //~ ERROR BaseDefault
+>(T);
 
 #[rustc_object_lifetime_default]
-struct B<'a,T>(&'a (), T); //~ ERROR BaseDefault
+struct B<
+    'a,
+    T, //~ ERROR BaseDefault
+>(&'a (), T);
 
 #[rustc_object_lifetime_default]
-struct C<'a,T:'a>(&'a T); //~ ERROR 'a
+struct C<
+    'a,
+    T: 'a, //~ ERROR 'a
+>(&'a T);
 
 #[rustc_object_lifetime_default]
-struct D<'a,'b,T:'a+'b>(&'a T, &'b T); //~ ERROR Ambiguous
+struct D<
+    'a,
+    'b,
+    T: 'a + 'b, //~ ERROR Ambiguous
+>(&'a T, &'b T);
 
 #[rustc_object_lifetime_default]
-struct E<'a,'b:'a,T:'b>(&'a T, &'b T); //~ ERROR 'b
+struct E<
+    'a,
+    'b: 'a,
+    T: 'b, //~ ERROR 'b
+>(&'a T, &'b T);
 
 #[rustc_object_lifetime_default]
-struct F<'a,'b,T:'a,U:'b>(&'a T, &'b U); //~ ERROR 'a,'b
+struct F<
+    'a,
+    'b,
+    T: 'a, //~ ERROR 'a
+    U: 'b, //~ ERROR 'b
+>(&'a T, &'b U);
 
 #[rustc_object_lifetime_default]
-struct G<'a,'b,T:'a,U:'a+'b>(&'a T, &'b U); //~ ERROR 'a,Ambiguous
+struct G<
+    'a,
+    'b,
+    T: 'a,      //~ ERROR 'a
+    U: 'a + 'b, //~ ERROR Ambiguous
+>(&'a T, &'b U);
 
-fn main() { }
+fn main() {}
diff --git a/src/test/ui/object-lifetime/object-lifetime-default.stderr b/src/test/ui/object-lifetime/object-lifetime-default.stderr
index 60cb98c8fd37..a58afad3ef2b 100644
--- a/src/test/ui/object-lifetime/object-lifetime-default.stderr
+++ b/src/test/ui/object-lifetime/object-lifetime-default.stderr
@@ -1,44 +1,56 @@
 error: BaseDefault
-  --> $DIR/object-lifetime-default.rs:4:1
+  --> $DIR/object-lifetime-default.rs:5:5
    |
-LL | struct A<T>(T);
-   | ^^^^^^^^^^^^^^^
+LL |     T,
+   |     ^
 
 error: BaseDefault
-  --> $DIR/object-lifetime-default.rs:7:1
+  --> $DIR/object-lifetime-default.rs:11:5
    |
-LL | struct B<'a,T>(&'a (), T);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     T,
+   |     ^
 
 error: 'a
-  --> $DIR/object-lifetime-default.rs:10:1
+  --> $DIR/object-lifetime-default.rs:17:5
    |
-LL | struct C<'a,T:'a>(&'a T);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     T: 'a,
+   |     ^
 
 error: Ambiguous
-  --> $DIR/object-lifetime-default.rs:13:1
+  --> $DIR/object-lifetime-default.rs:24:5
    |
-LL | struct D<'a,'b,T:'a+'b>(&'a T, &'b T);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     T: 'a + 'b,
+   |     ^
 
 error: 'b
-  --> $DIR/object-lifetime-default.rs:16:1
+  --> $DIR/object-lifetime-default.rs:31:5
    |
-LL | struct E<'a,'b:'a,T:'b>(&'a T, &'b T);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     T: 'b,
+   |     ^
 
-error: 'a,'b
-  --> $DIR/object-lifetime-default.rs:19:1
+error: 'a
+  --> $DIR/object-lifetime-default.rs:38:5
    |
-LL | struct F<'a,'b,T:'a,U:'b>(&'a T, &'b U);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     T: 'a,
+   |     ^
 
-error: 'a,Ambiguous
-  --> $DIR/object-lifetime-default.rs:22:1
+error: 'b
+  --> $DIR/object-lifetime-default.rs:39:5
    |
-LL | struct G<'a,'b,T:'a,U:'a+'b>(&'a T, &'b U);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     U: 'b,
+   |     ^
 
-error: aborting due to 7 previous errors
+error: 'a
+  --> $DIR/object-lifetime-default.rs:46:5
+   |
+LL |     T: 'a,
+   |     ^
+
+error: Ambiguous
+  --> $DIR/object-lifetime-default.rs:47:5
+   |
+LL |     U: 'a + 'b,
+   |     ^
+
+error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/on-unimplemented/enclosing-scope.rs b/src/test/ui/on-unimplemented/enclosing-scope.rs
deleted file mode 100644
index 881bff63f5f6..000000000000
--- a/src/test/ui/on-unimplemented/enclosing-scope.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// Test scope annotations from `enclosing_scope` parameter
-
-#![feature(rustc_attrs)]
-
-#[rustc_on_unimplemented(enclosing_scope="in this scope")]
-trait Trait{}
-
-struct Foo;
-
-fn f<T: Trait>(x: T) {}
-
-fn main() {
-    let x = || {
-        f(Foo{}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
-        let y = || {
-            f(Foo{}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
-        };
-    };
-
-    {
-        {
-            f(Foo{}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
-        }
-    }
-
-    f(Foo{}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
-}
diff --git a/src/test/ui/on-unimplemented/enclosing-scope.stderr b/src/test/ui/on-unimplemented/enclosing-scope.stderr
deleted file mode 100644
index 67759d02a161..000000000000
--- a/src/test/ui/on-unimplemented/enclosing-scope.stderr
+++ /dev/null
@@ -1,86 +0,0 @@
-error[E0277]: the trait bound `Foo: Trait` is not satisfied
-  --> $DIR/enclosing-scope.rs:14:11
-   |
-LL |       let x = || {
-   |  _____________-
-LL | |         f(Foo{});
-   | |         - ^^^^^ the trait `Trait` is not implemented for `Foo`
-   | |         |
-   | |         required by a bound introduced by this call
-LL | |         let y = || {
-LL | |             f(Foo{});
-LL | |         };
-LL | |     };
-   | |_____- in this scope
-   |
-note: required by a bound in `f`
-  --> $DIR/enclosing-scope.rs:10:9
-   |
-LL | fn f<T: Trait>(x: T) {}
-   |         ^^^^^ required by this bound in `f`
-
-error[E0277]: the trait bound `Foo: Trait` is not satisfied
-  --> $DIR/enclosing-scope.rs:16:15
-   |
-LL |           let y = || {
-   |  _________________-
-LL | |             f(Foo{});
-   | |             - ^^^^^ the trait `Trait` is not implemented for `Foo`
-   | |             |
-   | |             required by a bound introduced by this call
-LL | |         };
-   | |_________- in this scope
-   |
-note: required by a bound in `f`
-  --> $DIR/enclosing-scope.rs:10:9
-   |
-LL | fn f<T: Trait>(x: T) {}
-   |         ^^^^^ required by this bound in `f`
-
-error[E0277]: the trait bound `Foo: Trait` is not satisfied
-  --> $DIR/enclosing-scope.rs:22:15
-   |
-LL | / fn main() {
-LL | |     let x = || {
-LL | |         f(Foo{});
-LL | |         let y = || {
-...  |
-LL | |             f(Foo{});
-   | |             - ^^^^^ the trait `Trait` is not implemented for `Foo`
-   | |             |
-   | |             required by a bound introduced by this call
-...  |
-LL | |     f(Foo{});
-LL | | }
-   | |_- in this scope
-   |
-note: required by a bound in `f`
-  --> $DIR/enclosing-scope.rs:10:9
-   |
-LL | fn f<T: Trait>(x: T) {}
-   |         ^^^^^ required by this bound in `f`
-
-error[E0277]: the trait bound `Foo: Trait` is not satisfied
-  --> $DIR/enclosing-scope.rs:26:7
-   |
-LL | / fn main() {
-LL | |     let x = || {
-LL | |         f(Foo{});
-LL | |         let y = || {
-...  |
-LL | |     f(Foo{});
-   | |     - ^^^^^ the trait `Trait` is not implemented for `Foo`
-   | |     |
-   | |     required by a bound introduced by this call
-LL | | }
-   | |_- in this scope
-   |
-note: required by a bound in `f`
-  --> $DIR/enclosing-scope.rs:10:9
-   |
-LL | fn f<T: Trait>(x: T) {}
-   |         ^^^^^ required by this bound in `f`
-
-error: aborting due to 4 previous errors
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/on-unimplemented/multiple-impls.rs b/src/test/ui/on-unimplemented/multiple-impls.rs
index 79c40f650db8..a32fd4566231 100644
--- a/src/test/ui/on-unimplemented/multiple-impls.rs
+++ b/src/test/ui/on-unimplemented/multiple-impls.rs
@@ -32,8 +32,14 @@ impl Index<Bar<usize>> for [i32] {
 fn main() {
     Index::index(&[] as &[i32], 2u32);
     //~^ ERROR E0277
+    //~| ERROR E0277
+    //~| ERROR E0277
     Index::index(&[] as &[i32], Foo(2u32));
     //~^ ERROR E0277
+    //~| ERROR E0277
+    //~| ERROR E0277
     Index::index(&[] as &[i32], Bar(2u32));
     //~^ ERROR E0277
+    //~| ERROR E0277
+    //~| ERROR E0277
 }
diff --git a/src/test/ui/on-unimplemented/multiple-impls.stderr b/src/test/ui/on-unimplemented/multiple-impls.stderr
index d47a398412fe..d628b159a66d 100644
--- a/src/test/ui/on-unimplemented/multiple-impls.stderr
+++ b/src/test/ui/on-unimplemented/multiple-impls.stderr
@@ -11,8 +11,19 @@ LL |     Index::index(&[] as &[i32], 2u32);
              <[i32] as Index<Bar<usize>>>
              <[i32] as Index<Foo<usize>>>
 
+error[E0277]: the trait bound `[i32]: Index<u32>` is not satisfied
+  --> $DIR/multiple-impls.rs:33:5
+   |
+LL |     Index::index(&[] as &[i32], 2u32);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trait message
+   |
+   = help: the trait `Index<u32>` is not implemented for `[i32]`
+   = help: the following other types implement trait `Index<Idx>`:
+             <[i32] as Index<Bar<usize>>>
+             <[i32] as Index<Foo<usize>>>
+
 error[E0277]: the trait bound `[i32]: Index<Foo<u32>>` is not satisfied
-  --> $DIR/multiple-impls.rs:35:33
+  --> $DIR/multiple-impls.rs:37:33
    |
 LL |     Index::index(&[] as &[i32], Foo(2u32));
    |     ------------                ^^^^^^^^^ on impl for Foo
@@ -24,8 +35,19 @@ LL |     Index::index(&[] as &[i32], Foo(2u32));
              <[i32] as Index<Bar<usize>>>
              <[i32] as Index<Foo<usize>>>
 
+error[E0277]: the trait bound `[i32]: Index<Foo<u32>>` is not satisfied
+  --> $DIR/multiple-impls.rs:37:5
+   |
+LL |     Index::index(&[] as &[i32], Foo(2u32));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ on impl for Foo
+   |
+   = help: the trait `Index<Foo<u32>>` is not implemented for `[i32]`
+   = help: the following other types implement trait `Index<Idx>`:
+             <[i32] as Index<Bar<usize>>>
+             <[i32] as Index<Foo<usize>>>
+
 error[E0277]: the trait bound `[i32]: Index<Bar<u32>>` is not satisfied
-  --> $DIR/multiple-impls.rs:37:33
+  --> $DIR/multiple-impls.rs:41:33
    |
 LL |     Index::index(&[] as &[i32], Bar(2u32));
    |     ------------                ^^^^^^^^^ on impl for Bar
@@ -37,6 +59,50 @@ LL |     Index::index(&[] as &[i32], Bar(2u32));
              <[i32] as Index<Bar<usize>>>
              <[i32] as Index<Foo<usize>>>
 
-error: aborting due to 3 previous errors
+error[E0277]: the trait bound `[i32]: Index<Bar<u32>>` is not satisfied
+  --> $DIR/multiple-impls.rs:41:5
+   |
+LL |     Index::index(&[] as &[i32], Bar(2u32));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ on impl for Bar
+   |
+   = help: the trait `Index<Bar<u32>>` is not implemented for `[i32]`
+   = help: the following other types implement trait `Index<Idx>`:
+             <[i32] as Index<Bar<usize>>>
+             <[i32] as Index<Foo<usize>>>
+
+error[E0277]: the trait bound `[i32]: Index<u32>` is not satisfied
+  --> $DIR/multiple-impls.rs:33:5
+   |
+LL |     Index::index(&[] as &[i32], 2u32);
+   |     ^^^^^^^^^^^^ trait message
+   |
+   = help: the trait `Index<u32>` is not implemented for `[i32]`
+   = help: the following other types implement trait `Index<Idx>`:
+             <[i32] as Index<Bar<usize>>>
+             <[i32] as Index<Foo<usize>>>
+
+error[E0277]: the trait bound `[i32]: Index<Foo<u32>>` is not satisfied
+  --> $DIR/multiple-impls.rs:37:5
+   |
+LL |     Index::index(&[] as &[i32], Foo(2u32));
+   |     ^^^^^^^^^^^^ on impl for Foo
+   |
+   = help: the trait `Index<Foo<u32>>` is not implemented for `[i32]`
+   = help: the following other types implement trait `Index<Idx>`:
+             <[i32] as Index<Bar<usize>>>
+             <[i32] as Index<Foo<usize>>>
+
+error[E0277]: the trait bound `[i32]: Index<Bar<u32>>` is not satisfied
+  --> $DIR/multiple-impls.rs:41:5
+   |
+LL |     Index::index(&[] as &[i32], Bar(2u32));
+   |     ^^^^^^^^^^^^ on impl for Bar
+   |
+   = help: the trait `Index<Bar<u32>>` is not implemented for `[i32]`
+   = help: the following other types implement trait `Index<Idx>`:
+             <[i32] as Index<Bar<usize>>>
+             <[i32] as Index<Foo<usize>>>
+
+error: aborting due to 9 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/on-unimplemented/on-impl.rs b/src/test/ui/on-unimplemented/on-impl.rs
index b03e1f7c6a8d..d0537810ce11 100644
--- a/src/test/ui/on-unimplemented/on-impl.rs
+++ b/src/test/ui/on-unimplemented/on-impl.rs
@@ -21,4 +21,6 @@ impl Index<usize> for [i32] {
 fn main() {
     Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32);
     //~^ ERROR E0277
+    //~| ERROR E0277
+    //~| ERROR E0277
 }
diff --git a/src/test/ui/on-unimplemented/on-impl.stderr b/src/test/ui/on-unimplemented/on-impl.stderr
index 01315b854098..2253c5992a64 100644
--- a/src/test/ui/on-unimplemented/on-impl.stderr
+++ b/src/test/ui/on-unimplemented/on-impl.stderr
@@ -9,6 +9,24 @@ LL |     Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32);
    = help: the trait `Index<u32>` is not implemented for `[i32]`
    = help: the trait `Index<usize>` is implemented for `[i32]`
 
-error: aborting due to previous error
+error[E0277]: the trait bound `[i32]: Index<u32>` is not satisfied
+  --> $DIR/on-impl.rs:22:5
+   |
+LL |     Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ a usize is required to index into a slice
+   |
+   = help: the trait `Index<u32>` is not implemented for `[i32]`
+   = help: the trait `Index<usize>` is implemented for `[i32]`
+
+error[E0277]: the trait bound `[i32]: Index<u32>` is not satisfied
+  --> $DIR/on-impl.rs:22:5
+   |
+LL |     Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32);
+   |     ^^^^^^^^^^^^^^^^^^^ a usize is required to index into a slice
+   |
+   = help: the trait `Index<u32>` is not implemented for `[i32]`
+   = help: the trait `Index<usize>` is implemented for `[i32]`
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/on-unimplemented/parent-label.rs b/src/test/ui/on-unimplemented/parent-label.rs
new file mode 100644
index 000000000000..b65f6496831e
--- /dev/null
+++ b/src/test/ui/on-unimplemented/parent-label.rs
@@ -0,0 +1,27 @@
+// Test scope annotations from `parent_label` parameter
+
+#![feature(rustc_attrs)]
+
+#[rustc_on_unimplemented(parent_label = "in this scope")]
+trait Trait {}
+
+struct Foo;
+
+fn f<T: Trait>(x: T) {}
+
+fn main() {
+    let x = || {
+        f(Foo {}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
+        let y = || {
+            f(Foo {}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
+        };
+    };
+
+    {
+        {
+            f(Foo {}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
+        }
+    }
+
+    f(Foo {}); //~ ERROR the trait bound `Foo: Trait` is not satisfied
+}
diff --git a/src/test/ui/on-unimplemented/parent-label.stderr b/src/test/ui/on-unimplemented/parent-label.stderr
new file mode 100644
index 000000000000..8cd7412fd9d3
--- /dev/null
+++ b/src/test/ui/on-unimplemented/parent-label.stderr
@@ -0,0 +1,69 @@
+error[E0277]: the trait bound `Foo: Trait` is not satisfied
+  --> $DIR/parent-label.rs:14:11
+   |
+LL |     let x = || {
+   |             -- in this scope
+LL |         f(Foo {});
+   |         - ^^^^^^ the trait `Trait` is not implemented for `Foo`
+   |         |
+   |         required by a bound introduced by this call
+   |
+note: required by a bound in `f`
+  --> $DIR/parent-label.rs:10:9
+   |
+LL | fn f<T: Trait>(x: T) {}
+   |         ^^^^^ required by this bound in `f`
+
+error[E0277]: the trait bound `Foo: Trait` is not satisfied
+  --> $DIR/parent-label.rs:16:15
+   |
+LL |         let y = || {
+   |                 -- in this scope
+LL |             f(Foo {});
+   |             - ^^^^^^ the trait `Trait` is not implemented for `Foo`
+   |             |
+   |             required by a bound introduced by this call
+   |
+note: required by a bound in `f`
+  --> $DIR/parent-label.rs:10:9
+   |
+LL | fn f<T: Trait>(x: T) {}
+   |         ^^^^^ required by this bound in `f`
+
+error[E0277]: the trait bound `Foo: Trait` is not satisfied
+  --> $DIR/parent-label.rs:22:15
+   |
+LL | fn main() {
+   | --------- in this scope
+...
+LL |             f(Foo {});
+   |             - ^^^^^^ the trait `Trait` is not implemented for `Foo`
+   |             |
+   |             required by a bound introduced by this call
+   |
+note: required by a bound in `f`
+  --> $DIR/parent-label.rs:10:9
+   |
+LL | fn f<T: Trait>(x: T) {}
+   |         ^^^^^ required by this bound in `f`
+
+error[E0277]: the trait bound `Foo: Trait` is not satisfied
+  --> $DIR/parent-label.rs:26:7
+   |
+LL | fn main() {
+   | --------- in this scope
+...
+LL |     f(Foo {});
+   |     - ^^^^^^ the trait `Trait` is not implemented for `Foo`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a bound in `f`
+  --> $DIR/parent-label.rs:10:9
+   |
+LL | fn f<T: Trait>(x: T) {}
+   |         ^^^^^ required by this bound in `f`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/opt-in-copy.stderr b/src/test/ui/opt-in-copy.stderr
index 0a275f1aa41d..4461567df0a2 100644
--- a/src/test/ui/opt-in-copy.stderr
+++ b/src/test/ui/opt-in-copy.stderr
@@ -1,20 +1,20 @@
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/opt-in-copy.rs:7:6
+  --> $DIR/opt-in-copy.rs:7:15
    |
 LL |     but_i_cant: CantCopyThis,
    |     ------------------------ this field does not implement `Copy`
 ...
 LL | impl Copy for IWantToCopyThis {}
-   |      ^^^^
+   |               ^^^^^^^^^^^^^^^
 
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/opt-in-copy.rs:19:6
+  --> $DIR/opt-in-copy.rs:19:15
    |
 LL |     ButICant(CantCopyThisEither),
    |              ------------------ this field does not implement `Copy`
 ...
 LL | impl Copy for IWantToCopyThisToo {}
-   |      ^^^^
+   |               ^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/panic-handler/weak-lang-item.rs b/src/test/ui/panic-handler/weak-lang-item.rs
index df31e614cf80..14a07a9ef1b5 100644
--- a/src/test/ui/panic-handler/weak-lang-item.rs
+++ b/src/test/ui/panic-handler/weak-lang-item.rs
@@ -2,7 +2,7 @@
 // error-pattern: `#[panic_handler]` function required, but not found
 // error-pattern: language item required, but not found: `eh_personality`
 // needs-unwind since it affects the error output
-// ignore-emscripten compiled with panic=abort, personality not required
+// ignore-emscripten missing eh_catch_typeinfo lang item
 
 #![no_std]
 
diff --git a/src/test/ui/panic-runtime/need-abort-got-unwind.rs b/src/test/ui/panic-runtime/need-abort-got-unwind.rs
index c72fb96e357f..e92400931d23 100644
--- a/src/test/ui/panic-runtime/need-abort-got-unwind.rs
+++ b/src/test/ui/panic-runtime/need-abort-got-unwind.rs
@@ -2,7 +2,6 @@
 // needs-unwind
 // error-pattern:is incompatible with this crate's strategy of `unwind`
 // aux-build:needs-abort.rs
-// ignore-wasm32-bare compiled with panic=abort by default
 
 extern crate needs_abort;
 
diff --git a/src/test/ui/panic-runtime/transitive-link-a-bunch.rs b/src/test/ui/panic-runtime/transitive-link-a-bunch.rs
index 622535a75aff..0e74e300f00f 100644
--- a/src/test/ui/panic-runtime/transitive-link-a-bunch.rs
+++ b/src/test/ui/panic-runtime/transitive-link-a-bunch.rs
@@ -6,7 +6,6 @@
 // aux-build:wants-panic-runtime-abort.rs
 // aux-build:panic-runtime-lang-items.rs
 // error-pattern: is not compiled with this crate's panic strategy `unwind`
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![no_std]
 #![no_main]
diff --git a/src/test/ui/panic-runtime/want-unwind-got-abort.rs b/src/test/ui/panic-runtime/want-unwind-got-abort.rs
index 23bfea6af15c..b6174dc4efee 100644
--- a/src/test/ui/panic-runtime/want-unwind-got-abort.rs
+++ b/src/test/ui/panic-runtime/want-unwind-got-abort.rs
@@ -3,7 +3,6 @@
 // error-pattern:is not compiled with this crate's panic strategy `unwind`
 // aux-build:panic-runtime-abort.rs
 // aux-build:panic-runtime-lang-items.rs
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![no_std]
 #![no_main]
diff --git a/src/test/ui/panic-runtime/want-unwind-got-abort2.rs b/src/test/ui/panic-runtime/want-unwind-got-abort2.rs
index 7a2e48e2f10a..b54babbeffa3 100644
--- a/src/test/ui/panic-runtime/want-unwind-got-abort2.rs
+++ b/src/test/ui/panic-runtime/want-unwind-got-abort2.rs
@@ -4,7 +4,6 @@
 // aux-build:panic-runtime-abort.rs
 // aux-build:wants-panic-runtime-abort.rs
 // aux-build:panic-runtime-lang-items.rs
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![no_std]
 #![no_main]
diff --git a/src/test/ui/panic-while-printing.rs b/src/test/ui/panic-while-printing.rs
index 098f54ac23f6..3abedf2a764e 100644
--- a/src/test/ui/panic-while-printing.rs
+++ b/src/test/ui/panic-while-printing.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-emscripten no subprocess support
 
 #![feature(internal_output_capture)]
 
diff --git a/src/test/ui/panics/issue-47429-short-backtraces.legacy.run.stderr b/src/test/ui/panics/issue-47429-short-backtraces.legacy.run.stderr
index b6223b93764f..ac4ed8225bd8 100644
--- a/src/test/ui/panics/issue-47429-short-backtraces.legacy.run.stderr
+++ b/src/test/ui/panics/issue-47429-short-backtraces.legacy.run.stderr
@@ -1,4 +1,4 @@
-thread 'main' panicked at 'explicit panic', $DIR/issue-47429-short-backtraces.rs:22:5
+thread 'main' panicked at 'explicit panic', $DIR/issue-47429-short-backtraces.rs:23:5
 stack backtrace:
    0: std::panicking::begin_panic
    1: issue_47429_short_backtraces::main
diff --git a/src/test/ui/panics/issue-47429-short-backtraces.rs b/src/test/ui/panics/issue-47429-short-backtraces.rs
index f338ace6bb0d..58d0fa62c34e 100644
--- a/src/test/ui/panics/issue-47429-short-backtraces.rs
+++ b/src/test/ui/panics/issue-47429-short-backtraces.rs
@@ -12,6 +12,7 @@
 // ignore-wasm no panic or subprocess support
 // ignore-emscripten no panic or subprocess support
 // ignore-sgx no subprocess support
+// ignore-fuchsia Backtraces not symbolized
 
 // NOTE(eddyb) output differs between symbol mangling schemes
 // revisions: legacy v0
diff --git a/src/test/ui/panics/issue-47429-short-backtraces.v0.run.stderr b/src/test/ui/panics/issue-47429-short-backtraces.v0.run.stderr
index c2bea4492498..65401fe1c3d8 100644
--- a/src/test/ui/panics/issue-47429-short-backtraces.v0.run.stderr
+++ b/src/test/ui/panics/issue-47429-short-backtraces.v0.run.stderr
@@ -1,4 +1,4 @@
-thread 'main' panicked at 'explicit panic', $DIR/issue-47429-short-backtraces.rs:22:5
+thread 'main' panicked at 'explicit panic', $DIR/issue-47429-short-backtraces.rs:23:5
 stack backtrace:
    0: std::panicking::begin_panic::<&str>
    1: issue_47429_short_backtraces::main
diff --git a/src/test/ui/panics/runtime-switch.legacy.run.stderr b/src/test/ui/panics/runtime-switch.legacy.run.stderr
index f282f18839c6..0f76551630cc 100644
--- a/src/test/ui/panics/runtime-switch.legacy.run.stderr
+++ b/src/test/ui/panics/runtime-switch.legacy.run.stderr
@@ -1,4 +1,4 @@
-thread 'main' panicked at 'explicit panic', $DIR/runtime-switch.rs:25:5
+thread 'main' panicked at 'explicit panic', $DIR/runtime-switch.rs:26:5
 stack backtrace:
    0: std::panicking::begin_panic
    1: runtime_switch::main
diff --git a/src/test/ui/panics/runtime-switch.rs b/src/test/ui/panics/runtime-switch.rs
index 37ef961e2d01..882340e495c1 100644
--- a/src/test/ui/panics/runtime-switch.rs
+++ b/src/test/ui/panics/runtime-switch.rs
@@ -12,6 +12,7 @@
 // ignore-wasm no panic or subprocess support
 // ignore-emscripten no panic or subprocess support
 // ignore-sgx no subprocess support
+// ignore-fuchsia Backtrace not symbolized
 
 // NOTE(eddyb) output differs between symbol mangling schemes
 // revisions: legacy v0
diff --git a/src/test/ui/panics/runtime-switch.v0.run.stderr b/src/test/ui/panics/runtime-switch.v0.run.stderr
index 7ce9722e5edf..a4ae441317da 100644
--- a/src/test/ui/panics/runtime-switch.v0.run.stderr
+++ b/src/test/ui/panics/runtime-switch.v0.run.stderr
@@ -1,4 +1,4 @@
-thread 'main' panicked at 'explicit panic', $DIR/runtime-switch.rs:25:5
+thread 'main' panicked at 'explicit panic', $DIR/runtime-switch.rs:26:5
 stack backtrace:
    0: std::panicking::begin_panic::<&str>
    1: runtime_switch::main
diff --git a/src/test/ui/parser/do-not-suggest-suggest-semicolon-before-array.rs b/src/test/ui/parser/do-not-suggest-semicolon-before-array.rs
similarity index 100%
rename from src/test/ui/parser/do-not-suggest-suggest-semicolon-before-array.rs
rename to src/test/ui/parser/do-not-suggest-semicolon-before-array.rs
diff --git a/src/test/ui/parser/do-not-suggest-suggest-semicolon-before-array.stderr b/src/test/ui/parser/do-not-suggest-semicolon-before-array.stderr
similarity index 76%
rename from src/test/ui/parser/do-not-suggest-suggest-semicolon-before-array.stderr
rename to src/test/ui/parser/do-not-suggest-semicolon-before-array.stderr
index d6e8db803299..a9dd526321f5 100644
--- a/src/test/ui/parser/do-not-suggest-suggest-semicolon-before-array.stderr
+++ b/src/test/ui/parser/do-not-suggest-semicolon-before-array.stderr
@@ -1,5 +1,5 @@
 error: expected one of `.`, `?`, `]`, or an operator, found `,`
-  --> $DIR/do-not-suggest-suggest-semicolon-before-array.rs:5:5
+  --> $DIR/do-not-suggest-semicolon-before-array.rs:5:5
    |
 LL |     [1, 3)
    |     ^ ^ help: `]` may belong here
diff --git a/src/test/ui/parser/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.rs b/src/test/ui/parser/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.rs
new file mode 100644
index 000000000000..d6f7981813fc
--- /dev/null
+++ b/src/test/ui/parser/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.rs
@@ -0,0 +1,3 @@
+fn main() {
+    let _x = vec[1, 2, 3]; //~ ERROR expected one of `.`, `?`, `]`, or an operator
+}
diff --git a/src/test/ui/parser/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.stderr b/src/test/ui/parser/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.stderr
new file mode 100644
index 000000000000..2fe6a28eeb41
--- /dev/null
+++ b/src/test/ui/parser/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.stderr
@@ -0,0 +1,8 @@
+error: expected one of `.`, `?`, `]`, or an operator, found `,`
+  --> $DIR/do-not-suggest-semicolon-between-macro-without-exclamation-mark-and-array.rs:2:19
+   |
+LL |     let _x = vec[1, 2, 3];
+   |                   ^ expected one of `.`, `?`, `]`, or an operator
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/empty-impl-semicolon.rs b/src/test/ui/parser/empty-impl-semicolon.rs
index 207ebef642bf..2485f5b85520 100644
--- a/src/test/ui/parser/empty-impl-semicolon.rs
+++ b/src/test/ui/parser/empty-impl-semicolon.rs
@@ -1 +1,4 @@
-impl Foo; //~ ERROR expected one of `!`, `(`, `+`, `::`, `<`, `for`, `where`, or `{`, found `;`
+struct Foo;
+impl Foo; //~ ERROR expected `{}`, found `;`
+
+fn main() {}
diff --git a/src/test/ui/parser/empty-impl-semicolon.stderr b/src/test/ui/parser/empty-impl-semicolon.stderr
index 398eb5c898cd..6ed309eba939 100644
--- a/src/test/ui/parser/empty-impl-semicolon.stderr
+++ b/src/test/ui/parser/empty-impl-semicolon.stderr
@@ -1,8 +1,10 @@
-error: expected one of `!`, `(`, `+`, `::`, `<`, `for`, `where`, or `{`, found `;`
-  --> $DIR/empty-impl-semicolon.rs:1:9
+error: expected `{}`, found `;`
+  --> $DIR/empty-impl-semicolon.rs:2:9
    |
 LL | impl Foo;
-   |         ^ expected one of 8 possible tokens
+   |         ^
+   |
+   = help: try using `{}` instead
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/fn-header-semantic-fail.rs b/src/test/ui/parser/fn-header-semantic-fail.rs
index 8ff14fb1f304..cf5d3dab4aad 100644
--- a/src/test/ui/parser/fn-header-semantic-fail.rs
+++ b/src/test/ui/parser/fn-header-semantic-fail.rs
@@ -27,7 +27,6 @@ fn main() {
     struct Y;
     impl X for Y {
         async fn ft1() {} //~ ERROR functions in traits cannot be declared `async`
-        //~^ ERROR has an incompatible type for trait
         unsafe fn ft2() {} // OK.
         const fn ft3() {} //~ ERROR functions in traits cannot be declared const
         extern "C" fn ft4() {}
@@ -36,7 +35,6 @@ fn main() {
         //~| ERROR functions in traits cannot be declared const
         //~| ERROR functions cannot be both `const` and `async`
         //~| ERROR cycle detected
-        //~| ERROR has an incompatible type for trait
     }
 
     impl Y {
diff --git a/src/test/ui/parser/fn-header-semantic-fail.stderr b/src/test/ui/parser/fn-header-semantic-fail.stderr
index bc51ba8b8c5c..800b5a43a006 100644
--- a/src/test/ui/parser/fn-header-semantic-fail.stderr
+++ b/src/test/ui/parser/fn-header-semantic-fail.stderr
@@ -7,17 +7,6 @@ LL |     const async unsafe extern "C" fn ff5() {}
    |     |     `async` because of this
    |     `const` because of this
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:17:9
-   |
-LL |         async fn ft1();
-   |         -----^^^^^^^^^^
-   |         |
-   |         `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 error[E0379]: functions in traits cannot be declared const
   --> $DIR/fn-header-semantic-fail.rs:19:9
    |
@@ -30,17 +19,6 @@ error[E0379]: functions in traits cannot be declared const
 LL |         const async unsafe extern "C" fn ft5();
    |         ^^^^^ functions in traits cannot be const
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:21:9
-   |
-LL |         const async unsafe extern "C" fn ft5();
-   |         ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |               |
-   |               `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:21:9
    |
@@ -50,42 +28,20 @@ LL |         const async unsafe extern "C" fn ft5();
    |         |     `async` because of this
    |         `const` because of this
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:29:9
-   |
-LL |         async fn ft1() {}
-   |         -----^^^^^^^^^^^^
-   |         |
-   |         `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 error[E0379]: functions in traits cannot be declared const
-  --> $DIR/fn-header-semantic-fail.rs:32:9
+  --> $DIR/fn-header-semantic-fail.rs:31:9
    |
 LL |         const fn ft3() {}
    |         ^^^^^ functions in traits cannot be const
 
 error[E0379]: functions in traits cannot be declared const
-  --> $DIR/fn-header-semantic-fail.rs:34:9
+  --> $DIR/fn-header-semantic-fail.rs:33:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^ functions in traits cannot be const
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:34:9
-   |
-LL |         const async unsafe extern "C" fn ft5() {}
-   |         ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |               |
-   |               `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 error: functions cannot be both `const` and `async`
-  --> $DIR/fn-header-semantic-fail.rs:34:9
+  --> $DIR/fn-header-semantic-fail.rs:33:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^-^^^^^------------------------------
@@ -94,7 +50,7 @@ LL |         const async unsafe extern "C" fn ft5() {}
    |         `const` because of this
 
 error: functions cannot be both `const` and `async`
-  --> $DIR/fn-header-semantic-fail.rs:47:9
+  --> $DIR/fn-header-semantic-fail.rs:45:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
    |         ^^^^^-^^^^^------------------------------
@@ -103,7 +59,7 @@ LL |         const async unsafe extern "C" fn fi5() {}
    |         `const` because of this
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:53:18
+  --> $DIR/fn-header-semantic-fail.rs:51:18
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -116,7 +72,7 @@ LL |         fn fe1();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:54:19
+  --> $DIR/fn-header-semantic-fail.rs:52:19
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -130,7 +86,7 @@ LL |         fn fe2();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:55:18
+  --> $DIR/fn-header-semantic-fail.rs:53:18
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -144,7 +100,7 @@ LL |         fn fe3();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:56:23
+  --> $DIR/fn-header-semantic-fail.rs:54:23
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -158,7 +114,7 @@ LL |         fn fe4();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:57:42
+  --> $DIR/fn-header-semantic-fail.rs:55:42
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -172,7 +128,7 @@ LL |         fn fe5();
    |         ~~
 
 error: functions cannot be both `const` and `async`
-  --> $DIR/fn-header-semantic-fail.rs:57:9
+  --> $DIR/fn-header-semantic-fail.rs:55:9
    |
 LL |         const async unsafe extern "C" fn fe5();
    |         ^^^^^-^^^^^----------------------------
@@ -180,6 +136,58 @@ LL |         const async unsafe extern "C" fn fe5();
    |         |     `async` because of this
    |         `const` because of this
 
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/fn-header-semantic-fail.rs:17:9
+   |
+LL |         async fn ft1();
+   |         -----^^^^^^^^^^
+   |         |
+   |         `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/fn-header-semantic-fail.rs:21:9
+   |
+LL |         const async unsafe extern "C" fn ft5();
+   |         ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |               |
+   |               `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/fn-header-semantic-fail.rs:29:9
+   |
+LL |         async fn ft1() {}
+   |         -----^^^^^^^^^
+   |         |
+   |         `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/fn-header-semantic-fail.rs:33:9
+   |
+LL |         const async unsafe extern "C" fn ft5() {}
+   |         ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |               |
+   |               `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
 error[E0391]: cycle detected when computing type of `main::ff5::{opaque#0}`
   --> $DIR/fn-header-semantic-fail.rs:12:44
    |
@@ -216,60 +224,24 @@ LL | |     }
 LL | | }
    | |_^
 
-error[E0053]: method `ft1` has an incompatible type for trait
-  --> $DIR/fn-header-semantic-fail.rs:29:24
-   |
-LL |         async fn ft1() {}
-   |                        ^
-   |                        |
-   |                        checked the `Output` of this `async fn`, found opaque type
-   |                        expected `()`, found opaque type
-   |
-   = note: while checking the return type of the `async fn`
-note: type in trait
-  --> $DIR/fn-header-semantic-fail.rs:17:23
-   |
-LL |         async fn ft1();
-   |                       ^
-   = note: expected fn pointer `fn()`
-              found fn pointer `fn() -> impl Future<Output = ()>`
-
-error[E0053]: method `ft5` has an incompatible type for trait
-  --> $DIR/fn-header-semantic-fail.rs:34:48
-   |
-LL |         const async unsafe extern "C" fn ft5() {}
-   |                                                ^
-   |                                                |
-   |                                                checked the `Output` of this `async fn`, found opaque type
-   |                                                expected `()`, found opaque type
-   |
-   = note: while checking the return type of the `async fn`
-note: type in trait
-  --> $DIR/fn-header-semantic-fail.rs:21:47
-   |
-LL |         const async unsafe extern "C" fn ft5();
-   |                                               ^
-   = note: expected fn pointer `unsafe extern "C" fn()`
-              found fn pointer `unsafe extern "C" fn() -> impl Future<Output = ()>`
-
 error[E0391]: cycle detected when computing type of `main::<impl at $DIR/fn-header-semantic-fail.rs:28:5: 28:17>::ft5::{opaque#0}`
-  --> $DIR/fn-header-semantic-fail.rs:34:48
+  --> $DIR/fn-header-semantic-fail.rs:33:48
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |                                                ^
    |
 note: ...which requires borrow-checking `main::<impl at $DIR/fn-header-semantic-fail.rs:28:5: 28:17>::ft5`...
-  --> $DIR/fn-header-semantic-fail.rs:34:9
+  --> $DIR/fn-header-semantic-fail.rs:33:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires processing `main::<impl at $DIR/fn-header-semantic-fail.rs:28:5: 28:17>::ft5`...
-  --> $DIR/fn-header-semantic-fail.rs:34:9
+  --> $DIR/fn-header-semantic-fail.rs:33:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires const checking `main::<impl at $DIR/fn-header-semantic-fail.rs:28:5: 28:17>::ft5`...
-  --> $DIR/fn-header-semantic-fail.rs:34:9
+  --> $DIR/fn-header-semantic-fail.rs:33:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -288,30 +260,30 @@ LL | |     }
 LL | | }
    | |_^
 
-error[E0391]: cycle detected when computing type of `main::<impl at $DIR/fn-header-semantic-fail.rs:42:5: 42:11>::fi5::{opaque#0}`
-  --> $DIR/fn-header-semantic-fail.rs:47:48
+error[E0391]: cycle detected when computing type of `main::<impl at $DIR/fn-header-semantic-fail.rs:40:5: 40:11>::fi5::{opaque#0}`
+  --> $DIR/fn-header-semantic-fail.rs:45:48
    |
 LL |         const async unsafe extern "C" fn fi5() {}
    |                                                ^
    |
-note: ...which requires borrow-checking `main::<impl at $DIR/fn-header-semantic-fail.rs:42:5: 42:11>::fi5`...
-  --> $DIR/fn-header-semantic-fail.rs:47:9
+note: ...which requires borrow-checking `main::<impl at $DIR/fn-header-semantic-fail.rs:40:5: 40:11>::fi5`...
+  --> $DIR/fn-header-semantic-fail.rs:45:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing `main::<impl at $DIR/fn-header-semantic-fail.rs:42:5: 42:11>::fi5`...
-  --> $DIR/fn-header-semantic-fail.rs:47:9
+note: ...which requires processing `main::<impl at $DIR/fn-header-semantic-fail.rs:40:5: 40:11>::fi5`...
+  --> $DIR/fn-header-semantic-fail.rs:45:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires const checking `main::<impl at $DIR/fn-header-semantic-fail.rs:42:5: 42:11>::fi5`...
-  --> $DIR/fn-header-semantic-fail.rs:47:9
+note: ...which requires const checking `main::<impl at $DIR/fn-header-semantic-fail.rs:40:5: 40:11>::fi5`...
+  --> $DIR/fn-header-semantic-fail.rs:45:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which requires computing whether `impl core::future::future::Future<Output = ()>` is freeze...
    = note: ...which requires evaluating trait selection obligation `impl core::future::future::Future<Output = ()>: core::marker::Freeze`...
-   = note: ...which again requires computing type of `main::<impl at $DIR/fn-header-semantic-fail.rs:42:5: 42:11>::fi5::{opaque#0}`, completing the cycle
+   = note: ...which again requires computing type of `main::<impl at $DIR/fn-header-semantic-fail.rs:40:5: 40:11>::fi5::{opaque#0}`, completing the cycle
 note: cycle used when checking item types in top-level module
   --> $DIR/fn-header-semantic-fail.rs:5:1
    |
@@ -324,7 +296,7 @@ LL | |     }
 LL | | }
    | |_^
 
-error: aborting due to 23 previous errors
+error: aborting due to 21 previous errors
 
-Some errors have detailed explanations: E0053, E0379, E0391, E0706.
-For more information about an error, try `rustc --explain E0053`.
+Some errors have detailed explanations: E0379, E0391, E0706.
+For more information about an error, try `rustc --explain E0379`.
diff --git a/src/test/ui/parser/impl-item-type-no-body-semantic-fail.rs b/src/test/ui/parser/impl-item-type-no-body-semantic-fail.rs
index 9871cb8fe3ee..1291a021bef5 100644
--- a/src/test/ui/parser/impl-item-type-no-body-semantic-fail.rs
+++ b/src/test/ui/parser/impl-item-type-no-body-semantic-fail.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 fn main() {}
 
 struct X;
diff --git a/src/test/ui/parser/impl-item-type-no-body-semantic-fail.stderr b/src/test/ui/parser/impl-item-type-no-body-semantic-fail.stderr
index 4b398d791c4d..3856754e080a 100644
--- a/src/test/ui/parser/impl-item-type-no-body-semantic-fail.stderr
+++ b/src/test/ui/parser/impl-item-type-no-body-semantic-fail.stderr
@@ -1,5 +1,5 @@
 error: associated type in `impl` without body
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:8:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:6:5
    |
 LL |     type Y;
    |     ^^^^^^-
@@ -7,7 +7,7 @@ LL |     type Y;
    |           help: provide a definition for the type: `= <type>;`
 
 error: associated type in `impl` without body
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:11:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:9:5
    |
 LL |     type Z: Ord;
    |     ^^^^^^^^^^^-
@@ -15,13 +15,13 @@ LL |     type Z: Ord;
    |                help: provide a definition for the type: `= <type>;`
 
 error: bounds on `type`s in `impl`s have no effect
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:11:13
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:9:13
    |
 LL |     type Z: Ord;
    |             ^^^
 
 error: associated type in `impl` without body
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:15:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:13:5
    |
 LL |     type W: Ord where Self: Eq;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^-
@@ -29,13 +29,13 @@ LL |     type W: Ord where Self: Eq;
    |                               help: provide a definition for the type: `= <type>;`
 
 error: bounds on `type`s in `impl`s have no effect
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:15:13
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:13:13
    |
 LL |     type W: Ord where Self: Eq;
    |             ^^^
 
 error: associated type in `impl` without body
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:19:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:17:5
    |
 LL |     type W where Self: Eq;
    |     ^^^^^^^^^^^^^^^^^^^^^-
@@ -43,7 +43,7 @@ LL |     type W where Self: Eq;
    |                          help: provide a definition for the type: `= <type>;`
 
 error[E0658]: inherent associated types are unstable
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:8:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:6:5
    |
 LL |     type Y;
    |     ^^^^^^^
@@ -52,7 +52,7 @@ LL |     type Y;
    = help: add `#![feature(inherent_associated_types)]` to the crate attributes to enable
 
 error[E0658]: inherent associated types are unstable
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:11:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:9:5
    |
 LL |     type Z: Ord;
    |     ^^^^^^^^^^^^
@@ -61,7 +61,7 @@ LL |     type Z: Ord;
    = help: add `#![feature(inherent_associated_types)]` to the crate attributes to enable
 
 error[E0658]: inherent associated types are unstable
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:15:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:13:5
    |
 LL |     type W: Ord where Self: Eq;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -70,7 +70,7 @@ LL |     type W: Ord where Self: Eq;
    = help: add `#![feature(inherent_associated_types)]` to the crate attributes to enable
 
 error[E0658]: inherent associated types are unstable
-  --> $DIR/impl-item-type-no-body-semantic-fail.rs:19:5
+  --> $DIR/impl-item-type-no-body-semantic-fail.rs:17:5
    |
 LL |     type W where Self: Eq;
    |     ^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/parser/increment-notfixed.stderr b/src/test/ui/parser/increment-notfixed.stderr
index 352d98cf82ec..ae55ae067143 100644
--- a/src/test/ui/parser/increment-notfixed.stderr
+++ b/src/test/ui/parser/increment-notfixed.stderr
@@ -8,9 +8,8 @@ help: use `+= 1` instead
    |
 LL |     { let tmp = i; i += 1; tmp };
    |     +++++++++++  ~~~~~~~~~~~~~~~
-LL -     i++;
-LL +     i += 1;
-   |
+LL |     i += 1;
+   |       ~~~~
 
 error: Rust has no postfix increment operator
   --> $DIR/increment-notfixed.rs:17:12
@@ -24,9 +23,8 @@ help: use `+= 1` instead
    |
 LL |     while { let tmp = i; i += 1; tmp } < 5 {
    |           +++++++++++  ~~~~~~~~~~~~~~~
-LL -     while i++ < 5 {
-LL +     while i += 1 < 5 {
-   |
+LL |     while i += 1 < 5 {
+   |             ~~~~
 
 error: Rust has no postfix increment operator
   --> $DIR/increment-notfixed.rs:25:8
@@ -38,9 +36,8 @@ help: use `+= 1` instead
    |
 LL |     { let tmp_ = tmp; tmp += 1; tmp_ };
    |     ++++++++++++    ~~~~~~~~~~~~~~~~~~
-LL -     tmp++;
-LL +     tmp += 1;
-   |
+LL |     tmp += 1;
+   |         ~~~~
 
 error: Rust has no postfix increment operator
   --> $DIR/increment-notfixed.rs:31:14
@@ -54,9 +51,8 @@ help: use `+= 1` instead
    |
 LL |     while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
    |           ++++++++++++    ~~~~~~~~~~~~~~~~~~
-LL -     while tmp++ < 5 {
-LL +     while tmp += 1 < 5 {
-   |
+LL |     while tmp += 1 < 5 {
+   |               ~~~~
 
 error: Rust has no postfix increment operator
   --> $DIR/increment-notfixed.rs:39:16
@@ -68,9 +64,8 @@ help: use `+= 1` instead
    |
 LL |     { let tmp = foo.bar.qux; foo.bar.qux += 1; tmp };
    |     +++++++++++            ~~~~~~~~~~~~~~~~~~~~~~~~~
-LL -     foo.bar.qux++;
-LL +     foo.bar.qux += 1;
-   |
+LL |     foo.bar.qux += 1;
+   |                 ~~~~
 
 error: Rust has no postfix increment operator
   --> $DIR/increment-notfixed.rs:49:10
@@ -82,9 +77,8 @@ help: use `+= 1` instead
    |
 LL |     { let tmp = s.tmp; s.tmp += 1; tmp };
    |     +++++++++++      ~~~~~~~~~~~~~~~~~~~
-LL -     s.tmp++;
-LL +     s.tmp += 1;
-   |
+LL |     s.tmp += 1;
+   |           ~~~~
 
 error: Rust has no prefix increment operator
   --> $DIR/increment-notfixed.rs:56:5
diff --git a/src/test/ui/parser/issue-101477-enum.fixed b/src/test/ui/parser/issue-101477-enum.fixed
new file mode 100644
index 000000000000..1dfeae22aea2
--- /dev/null
+++ b/src/test/ui/parser/issue-101477-enum.fixed
@@ -0,0 +1,10 @@
+// run-rustfix
+
+#[allow(dead_code)]
+enum Demo {
+    A = 1,
+    B = 2 //~ ERROR unexpected `==`
+    //~^ expected item, found `==`
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/issue-101477-enum.rs b/src/test/ui/parser/issue-101477-enum.rs
new file mode 100644
index 000000000000..ea7051d69a4c
--- /dev/null
+++ b/src/test/ui/parser/issue-101477-enum.rs
@@ -0,0 +1,10 @@
+// run-rustfix
+
+#[allow(dead_code)]
+enum Demo {
+    A = 1,
+    B == 2 //~ ERROR unexpected `==`
+    //~^ expected item, found `==`
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/issue-101477-enum.stderr b/src/test/ui/parser/issue-101477-enum.stderr
new file mode 100644
index 000000000000..bffc881bdc84
--- /dev/null
+++ b/src/test/ui/parser/issue-101477-enum.stderr
@@ -0,0 +1,14 @@
+error: unexpected `==`
+  --> $DIR/issue-101477-enum.rs:6:7
+   |
+LL |     B == 2
+   |       ^^ help: try using `=` instead
+
+error: expected item, found `==`
+  --> $DIR/issue-101477-enum.rs:6:7
+   |
+LL |     B == 2
+   |       ^^ expected item
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/parser/issue-101477-let.fixed b/src/test/ui/parser/issue-101477-let.fixed
new file mode 100644
index 000000000000..9989ad81524e
--- /dev/null
+++ b/src/test/ui/parser/issue-101477-let.fixed
@@ -0,0 +1,6 @@
+// run-rustfix
+
+fn main() {
+    let x = 2; //~ ERROR unexpected `==`
+    println!("x: {}", x)
+}
diff --git a/src/test/ui/parser/issue-101477-let.rs b/src/test/ui/parser/issue-101477-let.rs
new file mode 100644
index 000000000000..8b0e8bee1799
--- /dev/null
+++ b/src/test/ui/parser/issue-101477-let.rs
@@ -0,0 +1,6 @@
+// run-rustfix
+
+fn main() {
+    let x == 2; //~ ERROR unexpected `==`
+    println!("x: {}", x)
+}
diff --git a/src/test/ui/parser/issue-101477-let.stderr b/src/test/ui/parser/issue-101477-let.stderr
new file mode 100644
index 000000000000..1b30d4b17861
--- /dev/null
+++ b/src/test/ui/parser/issue-101477-let.stderr
@@ -0,0 +1,8 @@
+error: unexpected `==`
+  --> $DIR/issue-101477-let.rs:4:11
+   |
+LL |     let x == 2;
+   |           ^^ help: try using `=` instead
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/issues/issue-101540.rs b/src/test/ui/parser/issues/issue-101540.rs
new file mode 100644
index 000000000000..328ec6f906b1
--- /dev/null
+++ b/src/test/ui/parser/issues/issue-101540.rs
@@ -0,0 +1,7 @@
+struct S1 {
+    struct S2 {
+    //~^ ERROR structs are not allowed in struct definitions
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/issues/issue-101540.stderr b/src/test/ui/parser/issues/issue-101540.stderr
new file mode 100644
index 000000000000..53c7c9590e6c
--- /dev/null
+++ b/src/test/ui/parser/issues/issue-101540.stderr
@@ -0,0 +1,10 @@
+error: structs are not allowed in struct definitions
+  --> $DIR/issue-101540.rs:2:5
+   |
+LL |     struct S2 {
+   |     ^^^^^^^^^
+   |
+   = help: consider creating a new `struct` definition instead of nesting
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/issues/issue-14303-enum.rs b/src/test/ui/parser/issues/issue-14303-enum.rs
deleted file mode 100644
index a6106159805b..000000000000
--- a/src/test/ui/parser/issues/issue-14303-enum.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-enum X<'a, T, 'b> {
-//~^ ERROR lifetime parameters must be declared prior to type parameters
-    A(&'a &'b T)
-}
-
-fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303-enum.stderr b/src/test/ui/parser/issues/issue-14303-enum.stderr
deleted file mode 100644
index 55cef4cabacf..000000000000
--- a/src/test/ui/parser/issues/issue-14303-enum.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: lifetime parameters must be declared prior to type parameters
-  --> $DIR/issue-14303-enum.rs:1:15
-   |
-LL | enum X<'a, T, 'b> {
-   |       --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/parser/issues/issue-14303-fn-def.rs b/src/test/ui/parser/issues/issue-14303-fn-def.rs
deleted file mode 100644
index 221bd311e747..000000000000
--- a/src/test/ui/parser/issues/issue-14303-fn-def.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-fn foo<'a, T, 'b>(x: &'a T) {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
-
-fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303-fn-def.stderr b/src/test/ui/parser/issues/issue-14303-fn-def.stderr
deleted file mode 100644
index bacc922969d9..000000000000
--- a/src/test/ui/parser/issues/issue-14303-fn-def.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: lifetime parameters must be declared prior to type parameters
-  --> $DIR/issue-14303-fn-def.rs:1:15
-   |
-LL | fn foo<'a, T, 'b>(x: &'a T) {}
-   |       --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/parser/issues/issue-14303-impl.rs b/src/test/ui/parser/issues/issue-14303-impl.rs
deleted file mode 100644
index 4dc2c6660180..000000000000
--- a/src/test/ui/parser/issues/issue-14303-impl.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-struct X<T>(T);
-
-impl<'a, T, 'b> X<T> {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
-
-fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303-impl.stderr b/src/test/ui/parser/issues/issue-14303-impl.stderr
deleted file mode 100644
index d6be02f70fd2..000000000000
--- a/src/test/ui/parser/issues/issue-14303-impl.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: lifetime parameters must be declared prior to type parameters
-  --> $DIR/issue-14303-impl.rs:3:13
-   |
-LL | impl<'a, T, 'b> X<T> {}
-   |     --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/parser/issues/issue-14303-path.rs b/src/test/ui/parser/issues/issue-14303-path.rs
deleted file mode 100644
index 89ef914aba23..000000000000
--- a/src/test/ui/parser/issues/issue-14303-path.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-mod foo {
-    pub struct X<'a, 'b, 'c, T> {
-        a: &'a str,
-        b: &'b str,
-        c: &'c str,
-        t: T,
-    }
-}
-
-fn bar<'a, 'b, 'c, T>(x: foo::X<'a, T, 'b, 'c>) {}
-//~^ ERROR type provided when a lifetime was expected
-
-fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303-path.stderr b/src/test/ui/parser/issues/issue-14303-path.stderr
deleted file mode 100644
index 841e63ecbe9d..000000000000
--- a/src/test/ui/parser/issues/issue-14303-path.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0747]: type provided when a lifetime was expected
-  --> $DIR/issue-14303-path.rs:10:37
-   |
-LL | fn bar<'a, 'b, 'c, T>(x: foo::X<'a, T, 'b, 'c>) {}
-   |                                     ^
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0747`.
diff --git a/src/test/ui/parser/issues/issue-14303-struct.rs b/src/test/ui/parser/issues/issue-14303-struct.rs
deleted file mode 100644
index 0bd10b4d0851..000000000000
--- a/src/test/ui/parser/issues/issue-14303-struct.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-struct X<'a, T, 'b> {
-//~^ ERROR lifetime parameters must be declared prior to type parameters
-    x: &'a &'b T
-}
-
-fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303-struct.stderr b/src/test/ui/parser/issues/issue-14303-struct.stderr
deleted file mode 100644
index fa62a39f2416..000000000000
--- a/src/test/ui/parser/issues/issue-14303-struct.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: lifetime parameters must be declared prior to type parameters
-  --> $DIR/issue-14303-struct.rs:1:17
-   |
-LL | struct X<'a, T, 'b> {
-   |         --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/parser/issues/issue-14303-trait.rs b/src/test/ui/parser/issues/issue-14303-trait.rs
deleted file mode 100644
index f253de92d92d..000000000000
--- a/src/test/ui/parser/issues/issue-14303-trait.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-trait Foo<'a, T, 'b> {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
-
-fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303-trait.stderr b/src/test/ui/parser/issues/issue-14303-trait.stderr
deleted file mode 100644
index 75cd67a9ded8..000000000000
--- a/src/test/ui/parser/issues/issue-14303-trait.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: lifetime parameters must be declared prior to type parameters
-  --> $DIR/issue-14303-trait.rs:1:18
-   |
-LL | trait Foo<'a, T, 'b> {}
-   |          --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/parser/issues/issue-14303.rs b/src/test/ui/parser/issues/issue-14303.rs
new file mode 100644
index 000000000000..82850d77aa92
--- /dev/null
+++ b/src/test/ui/parser/issues/issue-14303.rs
@@ -0,0 +1,33 @@
+enum Enum<'a, T, 'b> {
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
+    A(&'a &'b T)
+}
+
+struct Struct<'a, T, 'b> {
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
+    x: &'a &'b T
+}
+
+trait Trait<'a, T, 'b> {}
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
+
+fn foo<'a, T, 'b>(x: &'a T) {}
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
+
+struct Y<T>(T);
+impl<'a, T, 'b> Y<T> {}
+//~^ ERROR lifetime parameters must be declared prior to type and const parameters
+
+mod bar {
+    pub struct X<'a, 'b, 'c, T> {
+        a: &'a str,
+        b: &'b str,
+        c: &'c str,
+        t: T,
+    }
+}
+
+fn bar<'a, 'b, 'c, T>(x: bar::X<'a, T, 'b, 'c>) {}
+//~^ ERROR type provided when a lifetime was expected
+
+fn main() {}
diff --git a/src/test/ui/parser/issues/issue-14303.stderr b/src/test/ui/parser/issues/issue-14303.stderr
new file mode 100644
index 000000000000..f121107c0958
--- /dev/null
+++ b/src/test/ui/parser/issues/issue-14303.stderr
@@ -0,0 +1,39 @@
+error: lifetime parameters must be declared prior to type and const parameters
+  --> $DIR/issue-14303.rs:1:18
+   |
+LL | enum Enum<'a, T, 'b> {
+   |          --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
+
+error: lifetime parameters must be declared prior to type and const parameters
+  --> $DIR/issue-14303.rs:6:22
+   |
+LL | struct Struct<'a, T, 'b> {
+   |              --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
+
+error: lifetime parameters must be declared prior to type and const parameters
+  --> $DIR/issue-14303.rs:11:20
+   |
+LL | trait Trait<'a, T, 'b> {}
+   |            --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
+
+error: lifetime parameters must be declared prior to type and const parameters
+  --> $DIR/issue-14303.rs:14:15
+   |
+LL | fn foo<'a, T, 'b>(x: &'a T) {}
+   |       --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
+
+error: lifetime parameters must be declared prior to type and const parameters
+  --> $DIR/issue-14303.rs:18:13
+   |
+LL | impl<'a, T, 'b> Y<T> {}
+   |     --------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, 'b, T>`
+
+error[E0747]: type provided when a lifetime was expected
+  --> $DIR/issue-14303.rs:30:37
+   |
+LL | fn bar<'a, 'b, 'c, T>(x: bar::X<'a, T, 'b, 'c>) {}
+   |                                     ^
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0747`.
diff --git a/src/test/ui/parser/issues/issue-8537.stderr b/src/test/ui/parser/issues/issue-8537.stderr
index 505d830ef3e8..523cc9dc588f 100644
--- a/src/test/ui/parser/issues/issue-8537.stderr
+++ b/src/test/ui/parser/issues/issue-8537.stderr
@@ -4,7 +4,7 @@ error[E0703]: invalid ABI: found `invalid-ab_isize`
 LL |   "invalid-ab_isize"
    |   ^^^^^^^^^^^^^^^^^^ invalid ABI
    |
-   = help: valid ABIs: Rust, C, C-unwind, cdecl, cdecl-unwind, stdcall, stdcall-unwind, fastcall, fastcall-unwind, vectorcall, vectorcall-unwind, thiscall, thiscall-unwind, aapcs, aapcs-unwind, win64, win64-unwind, sysv64, sysv64-unwind, ptx-kernel, msp430-interrupt, x86-interrupt, amdgpu-kernel, efiapi, avr-interrupt, avr-non-blocking-interrupt, C-cmse-nonsecure-call, wasm, system, system-unwind, rust-intrinsic, rust-call, platform-intrinsic, unadjusted, rust-cold
+   = note: invoke `rustc --print=calling-conventions` for a full list of supported calling conventions.
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/item-needs-block.rs b/src/test/ui/parser/item-needs-block.rs
new file mode 100644
index 000000000000..4edac588eee9
--- /dev/null
+++ b/src/test/ui/parser/item-needs-block.rs
@@ -0,0 +1,10 @@
+trait Trait;
+//~^ ERROR expected `{}`, found `;`
+
+impl Trait for ();
+//~^ ERROR expected `{}`, found `;`
+
+enum Enum;
+//~^ ERROR expected `{}`, found `;`
+
+fn main() {}
diff --git a/src/test/ui/parser/item-needs-block.stderr b/src/test/ui/parser/item-needs-block.stderr
new file mode 100644
index 000000000000..3cabd0c73a3c
--- /dev/null
+++ b/src/test/ui/parser/item-needs-block.stderr
@@ -0,0 +1,26 @@
+error: expected `{}`, found `;`
+  --> $DIR/item-needs-block.rs:1:12
+   |
+LL | trait Trait;
+   |            ^
+   |
+   = help: try using `{}` instead
+
+error: expected `{}`, found `;`
+  --> $DIR/item-needs-block.rs:4:18
+   |
+LL | impl Trait for ();
+   |                  ^
+   |
+   = help: try using `{}` instead
+
+error: expected `{}`, found `;`
+  --> $DIR/item-needs-block.rs:7:10
+   |
+LL | enum Enum;
+   |          ^
+   |
+   = help: try using `{}` instead
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/parser/public-instead-of-pub-3.fixed b/src/test/ui/parser/public-instead-of-pub-3.fixed
new file mode 100644
index 000000000000..14f620f41e8c
--- /dev/null
+++ b/src/test/ui/parser/public-instead-of-pub-3.fixed
@@ -0,0 +1,9 @@
+// run-rustfix
+mod test {
+    pub const X: i32 = 123;
+    //~^ ERROR expected one of `!` or `::`, found keyword `const`
+}
+
+fn main() {
+    println!("{}", test::X);
+}
diff --git a/src/test/ui/parser/public-instead-of-pub-3.rs b/src/test/ui/parser/public-instead-of-pub-3.rs
new file mode 100644
index 000000000000..ee27cb1a1a8b
--- /dev/null
+++ b/src/test/ui/parser/public-instead-of-pub-3.rs
@@ -0,0 +1,9 @@
+// run-rustfix
+mod test {
+    public const X: i32 = 123;
+    //~^ ERROR expected one of `!` or `::`, found keyword `const`
+}
+
+fn main() {
+    println!("{}", test::X);
+}
diff --git a/src/test/ui/parser/public-instead-of-pub-3.stderr b/src/test/ui/parser/public-instead-of-pub-3.stderr
new file mode 100644
index 000000000000..72efae08dda8
--- /dev/null
+++ b/src/test/ui/parser/public-instead-of-pub-3.stderr
@@ -0,0 +1,13 @@
+error: expected one of `!` or `::`, found keyword `const`
+  --> $DIR/public-instead-of-pub-3.rs:3:12
+   |
+LL |     public const X: i32 = 123;
+   |            ^^^^^ expected one of `!` or `::`
+   |
+help: write `pub` instead of `public` to make the item public
+   |
+LL |     pub const X: i32 = 123;
+   |     ~~~
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/recover-field-semi.rs b/src/test/ui/parser/recover-field-semi.rs
new file mode 100644
index 000000000000..b703578860ec
--- /dev/null
+++ b/src/test/ui/parser/recover-field-semi.rs
@@ -0,0 +1,16 @@
+struct Foo {
+    foo: i32;
+    //~^ ERROR struct fields are separated by `,`
+}
+
+union Bar { //~ ERROR
+    foo: i32;
+    //~^ ERROR union fields are separated by `,`
+}
+
+enum Baz {
+    Qux { foo: i32; }
+    //~^ ERROR struct fields are separated by `,`
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/recover-field-semi.stderr b/src/test/ui/parser/recover-field-semi.stderr
new file mode 100644
index 000000000000..657366db9b4b
--- /dev/null
+++ b/src/test/ui/parser/recover-field-semi.stderr
@@ -0,0 +1,29 @@
+error: struct fields are separated by `,`
+  --> $DIR/recover-field-semi.rs:2:13
+   |
+LL |     foo: i32;
+   |             ^ help: replace `;` with `,`
+
+error: union fields are separated by `,`
+  --> $DIR/recover-field-semi.rs:7:13
+   |
+LL |     foo: i32;
+   |             ^ help: replace `;` with `,`
+
+error: struct fields are separated by `,`
+  --> $DIR/recover-field-semi.rs:12:19
+   |
+LL |     Qux { foo: i32; }
+   |                   ^ help: replace `;` with `,`
+
+error: unions cannot have zero fields
+  --> $DIR/recover-field-semi.rs:6:1
+   |
+LL | / union Bar {
+LL | |     foo: i32;
+LL | |
+LL | | }
+   | |_^
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/ui/parser/removed-syntax-field-semicolon.rs b/src/test/ui/parser/removed-syntax-field-semicolon.rs
index ac28e21ae032..808f2a5cc381 100644
--- a/src/test/ui/parser/removed-syntax-field-semicolon.rs
+++ b/src/test/ui/parser/removed-syntax-field-semicolon.rs
@@ -1,6 +1,6 @@
 struct S {
     bar: ();
-    //~^ ERROR expected `,`, or `}`, found `;`
+    //~^ ERROR struct fields are separated by `,`
 }
 
 fn main() {}
diff --git a/src/test/ui/parser/removed-syntax-field-semicolon.stderr b/src/test/ui/parser/removed-syntax-field-semicolon.stderr
index fbefeb26a501..e4f75f672063 100644
--- a/src/test/ui/parser/removed-syntax-field-semicolon.stderr
+++ b/src/test/ui/parser/removed-syntax-field-semicolon.stderr
@@ -1,8 +1,8 @@
-error: expected `,`, or `}`, found `;`
+error: struct fields are separated by `,`
   --> $DIR/removed-syntax-field-semicolon.rs:2:12
    |
 LL |     bar: ();
-   |            ^
+   |            ^ help: replace `;` with `,`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/suggest-assoc-const.fixed b/src/test/ui/parser/suggest-assoc-const.fixed
new file mode 100644
index 000000000000..259f37b23a58
--- /dev/null
+++ b/src/test/ui/parser/suggest-assoc-const.fixed
@@ -0,0 +1,10 @@
+// Issue: 101797, Suggest associated const for incorrect use of let in traits
+// run-rustfix
+trait Trait {
+    const _X: i32;
+    //~^ ERROR non-item in item list
+}
+
+fn main() {
+
+}
diff --git a/src/test/ui/parser/suggest-assoc-const.rs b/src/test/ui/parser/suggest-assoc-const.rs
new file mode 100644
index 000000000000..c7be712ec076
--- /dev/null
+++ b/src/test/ui/parser/suggest-assoc-const.rs
@@ -0,0 +1,10 @@
+// Issue: 101797, Suggest associated const for incorrect use of let in traits
+// run-rustfix
+trait Trait {
+    let _X: i32;
+    //~^ ERROR non-item in item list
+}
+
+fn main() {
+
+}
diff --git a/src/test/ui/parser/suggest-assoc-const.stderr b/src/test/ui/parser/suggest-assoc-const.stderr
new file mode 100644
index 000000000000..2ddfa07c5be4
--- /dev/null
+++ b/src/test/ui/parser/suggest-assoc-const.stderr
@@ -0,0 +1,8 @@
+error: non-item in item list
+  --> $DIR/suggest-assoc-const.rs:4:5
+   |
+LL |     let _X: i32;
+   |     ^^^ help: consider using `const` instead of `let` for associated const: `const`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/suggest-suggest-semicolon-before-array.fixed b/src/test/ui/parser/suggest-semicolon-before-array.fixed
similarity index 100%
rename from src/test/ui/parser/suggest-suggest-semicolon-before-array.fixed
rename to src/test/ui/parser/suggest-semicolon-before-array.fixed
diff --git a/src/test/ui/parser/suggest-suggest-semicolon-before-array.rs b/src/test/ui/parser/suggest-semicolon-before-array.rs
similarity index 100%
rename from src/test/ui/parser/suggest-suggest-semicolon-before-array.rs
rename to src/test/ui/parser/suggest-semicolon-before-array.rs
diff --git a/src/test/ui/parser/suggest-suggest-semicolon-before-array.stderr b/src/test/ui/parser/suggest-semicolon-before-array.stderr
similarity index 75%
rename from src/test/ui/parser/suggest-suggest-semicolon-before-array.stderr
rename to src/test/ui/parser/suggest-semicolon-before-array.stderr
index bf86b43554d1..8a33321fbd56 100644
--- a/src/test/ui/parser/suggest-suggest-semicolon-before-array.stderr
+++ b/src/test/ui/parser/suggest-semicolon-before-array.stderr
@@ -1,5 +1,5 @@
 error: expected `;`, found `[`
-  --> $DIR/suggest-suggest-semicolon-before-array.rs:8:5
+  --> $DIR/suggest-semicolon-before-array.rs:8:5
    |
 LL |     [1, 3]
    |     ^
diff --git a/src/test/ui/parser/trait-object-delimiters.rs b/src/test/ui/parser/trait-object-delimiters.rs
index b5258eebb90a..cc04ac052040 100644
--- a/src/test/ui/parser/trait-object-delimiters.rs
+++ b/src/test/ui/parser/trait-object-delimiters.rs
@@ -6,7 +6,7 @@ fn foo1(_: &dyn Drop + AsRef<str>) {} //~ ERROR ambiguous `+` in a type
 fn foo2(_: &dyn (Drop + AsRef<str>)) {} //~ ERROR incorrect braces around trait bounds
 
 fn foo3(_: &dyn {Drop + AsRef<str>}) {} //~ ERROR expected parameter name, found `{`
-//~^ ERROR expected one of `!`, `(`, `)`, `,`, `?`, `for`, `~`, lifetime, or path, found `{`
+//~^ ERROR expected one of `!`, `(`, `)`, `*`, `,`, `?`, `for`, `~`, lifetime, or path, found `{`
 //~| ERROR at least one trait is required for an object type
 
 fn foo4(_: &dyn <Drop + AsRef<str>>) {} //~ ERROR expected identifier, found `<`
diff --git a/src/test/ui/parser/trait-object-delimiters.stderr b/src/test/ui/parser/trait-object-delimiters.stderr
index 6eb9c7238cb8..99c4515459d2 100644
--- a/src/test/ui/parser/trait-object-delimiters.stderr
+++ b/src/test/ui/parser/trait-object-delimiters.stderr
@@ -22,11 +22,11 @@ error: expected parameter name, found `{`
 LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {}
    |                 ^ expected parameter name
 
-error: expected one of `!`, `(`, `)`, `,`, `?`, `for`, `~`, lifetime, or path, found `{`
+error: expected one of `!`, `(`, `)`, `*`, `,`, `?`, `for`, `~`, lifetime, or path, found `{`
   --> $DIR/trait-object-delimiters.rs:8:17
    |
 LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {}
-   |                -^ expected one of 9 possible tokens
+   |                -^ expected one of 10 possible tokens
    |                |
    |                help: missing `,`
 
diff --git a/src/test/ui/parser/trait-object-trait-parens.stderr b/src/test/ui/parser/trait-object-trait-parens.stderr
index 7ee965bd2bab..823f75bfac86 100644
--- a/src/test/ui/parser/trait-object-trait-parens.stderr
+++ b/src/test/ui/parser/trait-object-trait-parens.stderr
@@ -27,9 +27,8 @@ LL |     let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
-LL +     let _: Box<dyn (Obj) + (?Sized) + (for<'a> Trait<'a>)>;
-   |
+LL |     let _: Box<dyn (Obj) + (?Sized) + (for<'a> Trait<'a>)>;
+   |                +++
 
 error[E0225]: only auto traits can be used as additional traits in a trait object
   --> $DIR/trait-object-trait-parens.rs:8:35
@@ -52,9 +51,8 @@ LL |     let _: Box<?Sized + (for<'a> Trait<'a>) + (Obj)>;
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     let _: Box<?Sized + (for<'a> Trait<'a>) + (Obj)>;
-LL +     let _: Box<dyn ?Sized + (for<'a> Trait<'a>) + (Obj)>;
-   |
+LL |     let _: Box<dyn ?Sized + (for<'a> Trait<'a>) + (Obj)>;
+   |                +++
 
 error[E0225]: only auto traits can be used as additional traits in a trait object
   --> $DIR/trait-object-trait-parens.rs:13:47
@@ -77,9 +75,8 @@ LL |     let _: Box<for<'a> Trait<'a> + (Obj) + (?Sized)>;
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     let _: Box<for<'a> Trait<'a> + (Obj) + (?Sized)>;
-LL +     let _: Box<dyn for<'a> Trait<'a> + (Obj) + (?Sized)>;
-   |
+LL |     let _: Box<dyn for<'a> Trait<'a> + (Obj) + (?Sized)>;
+   |                +++
 
 error[E0225]: only auto traits can be used as additional traits in a trait object
   --> $DIR/trait-object-trait-parens.rs:18:36
diff --git a/src/test/ui/parser/type-alias-where-fixable.fixed b/src/test/ui/parser/type-alias-where-fixable.fixed
index 41dd10676d5f..2f47c0d91fa9 100644
--- a/src/test/ui/parser/type-alias-where-fixable.fixed
+++ b/src/test/ui/parser/type-alias-where-fixable.fixed
@@ -1,8 +1,6 @@
 // check-pass
 // run-rustfix
 
-#![feature(generic_associated_types)]
-
 trait Trait {
     // Fine.
     type Assoc where u32: Copy;
diff --git a/src/test/ui/parser/type-alias-where-fixable.rs b/src/test/ui/parser/type-alias-where-fixable.rs
index 562a530a7f30..b20aa9398b58 100644
--- a/src/test/ui/parser/type-alias-where-fixable.rs
+++ b/src/test/ui/parser/type-alias-where-fixable.rs
@@ -1,8 +1,6 @@
 // check-pass
 // run-rustfix
 
-#![feature(generic_associated_types)]
-
 trait Trait {
     // Fine.
     type Assoc where u32: Copy;
diff --git a/src/test/ui/parser/type-alias-where-fixable.stderr b/src/test/ui/parser/type-alias-where-fixable.stderr
index abfeb62fcbb4..2e516d5c4787 100644
--- a/src/test/ui/parser/type-alias-where-fixable.stderr
+++ b/src/test/ui/parser/type-alias-where-fixable.stderr
@@ -1,5 +1,5 @@
 warning: where clause not allowed here
-  --> $DIR/type-alias-where-fixable.rs:15:16
+  --> $DIR/type-alias-where-fixable.rs:13:16
    |
 LL |     type Assoc where u32: Copy = ();
    |                ^^^^^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL +     type Assoc  = () where u32: Copy;
    |
 
 warning: where clause not allowed here
-  --> $DIR/type-alias-where-fixable.rs:18:17
+  --> $DIR/type-alias-where-fixable.rs:16:17
    |
 LL |     type Assoc2 where u32: Copy = () where i32: Copy;
    |                 ^^^^^^^^^^^^^^^
@@ -26,7 +26,7 @@ LL +     type Assoc2  = () where i32: Copy, u32: Copy;
    |
 
 warning: where clause not allowed here
-  --> $DIR/type-alias-where-fixable.rs:26:17
+  --> $DIR/type-alias-where-fixable.rs:24:17
    |
 LL |     type Assoc2 where u32: Copy, i32: Copy = ();
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/parser/type-alias-where.rs b/src/test/ui/parser/type-alias-where.rs
index f6e7dfb7b7b2..62e301cb4086 100644
--- a/src/test/ui/parser/type-alias-where.rs
+++ b/src/test/ui/parser/type-alias-where.rs
@@ -1,7 +1,5 @@
 // check-fail
 
-#![feature(generic_associated_types)]
-
 // Fine, but lints as unused
 type Foo where u32: Copy = ();
 // Not fine.
diff --git a/src/test/ui/parser/type-alias-where.stderr b/src/test/ui/parser/type-alias-where.stderr
index 8789d2665ad9..fb8381792669 100644
--- a/src/test/ui/parser/type-alias-where.stderr
+++ b/src/test/ui/parser/type-alias-where.stderr
@@ -1,5 +1,5 @@
 error: where clauses are not allowed after the type for type aliases
-  --> $DIR/type-alias-where.rs:8:15
+  --> $DIR/type-alias-where.rs:6:15
    |
 LL | type Bar = () where u32: Copy;
    |               ^^^^^^^^^^^^^^^
@@ -7,7 +7,7 @@ LL | type Bar = () where u32: Copy;
    = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
 
 error: where clauses are not allowed after the type for type aliases
-  --> $DIR/type-alias-where.rs:10:15
+  --> $DIR/type-alias-where.rs:8:15
    |
 LL | type Baz = () where;
    |               ^^^^^
diff --git a/src/test/ui/parser/unnecessary-let.rs b/src/test/ui/parser/unnecessary-let.rs
new file mode 100644
index 000000000000..6279109621d7
--- /dev/null
+++ b/src/test/ui/parser/unnecessary-let.rs
@@ -0,0 +1,11 @@
+fn main() {
+    for let x of [1, 2, 3] {}
+    //~^ ERROR expected pattern, found `let`
+    //~| ERROR missing `in` in `for` loop
+
+    match 1 {
+        let 1 => {}
+        //~^ ERROR expected pattern, found `let`
+        _ => {}
+    }
+}
diff --git a/src/test/ui/parser/unnecessary-let.stderr b/src/test/ui/parser/unnecessary-let.stderr
new file mode 100644
index 000000000000..952119cae3e2
--- /dev/null
+++ b/src/test/ui/parser/unnecessary-let.stderr
@@ -0,0 +1,20 @@
+error: expected pattern, found `let`
+  --> $DIR/unnecessary-let.rs:2:9
+   |
+LL |     for let x of [1, 2, 3] {}
+   |         ^^^ help: remove the unnecessary `let` keyword
+
+error: missing `in` in `for` loop
+  --> $DIR/unnecessary-let.rs:2:15
+   |
+LL |     for let x of [1, 2, 3] {}
+   |               ^^ help: try using `in` here instead
+
+error: expected pattern, found `let`
+  --> $DIR/unnecessary-let.rs:7:9
+   |
+LL |         let 1 => {}
+   |         ^^^ help: remove the unnecessary `let` keyword
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/pattern/bindings-after-at/bind-by-move-neither-can-live-while-the-other-survives-1.stderr b/src/test/ui/pattern/bindings-after-at/bind-by-move-neither-can-live-while-the-other-survives-1.stderr
index 4249a74b3ed6..fad84dda0e19 100644
--- a/src/test/ui/pattern/bindings-after-at/bind-by-move-neither-can-live-while-the-other-survives-1.stderr
+++ b/src/test/ui/pattern/bindings-after-at/bind-by-move-neither-can-live-while-the-other-survives-1.stderr
@@ -40,9 +40,8 @@ error[E0382]: borrow of moved value
   --> $DIR/bind-by-move-neither-can-live-while-the-other-survives-1.rs:12:14
    |
 LL |         Some(ref _y @ _z) => {}
-   |              ^^^^^^^^^--
-   |              |        |
-   |              |        value moved here
+   |              ^^^^^^   -- value moved here
+   |              |
    |              value borrowed here after move
    |
    = note: move occurs because value has type `X`, which does not implement the `Copy` trait
@@ -55,9 +54,8 @@ error[E0382]: borrow of moved value
   --> $DIR/bind-by-move-neither-can-live-while-the-other-survives-1.rs:26:14
    |
 LL |         Some(ref mut _y @ _z) => {}
-   |              ^^^^^^^^^^^^^--
-   |              |            |
-   |              |            value moved here
+   |              ^^^^^^^^^^   -- value moved here
+   |              |
    |              value borrowed here after move
    |
    = note: move occurs because value has type `X`, which does not implement the `Copy` trait
diff --git a/src/test/ui/pattern/bindings-after-at/bind-by-move-no-subbindings-fun-param.stderr b/src/test/ui/pattern/bindings-after-at/bind-by-move-no-subbindings-fun-param.stderr
index ee0885a014aa..a481ca468338 100644
--- a/src/test/ui/pattern/bindings-after-at/bind-by-move-no-subbindings-fun-param.stderr
+++ b/src/test/ui/pattern/bindings-after-at/bind-by-move-no-subbindings-fun-param.stderr
@@ -2,9 +2,8 @@ error[E0382]: use of partially moved value
   --> $DIR/bind-by-move-no-subbindings-fun-param.rs:7:6
    |
 LL | fn f(a @ A(u): A) -> Box<u8> {
-   |      ^^^^^^-^
-   |      |     |
-   |      |     value partially moved here
+   |      ^     - value partially moved here
+   |      |
    |      value used here after partial move
    |
    = note: partial move occurs because value has type `Box<u8>`, which does not implement the `Copy` trait
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-move-and-move.stderr b/src/test/ui/pattern/bindings-after-at/borrowck-move-and-move.stderr
index 8e00bf5c328b..a227cc583d68 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-move-and-move.stderr
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-move-and-move.stderr
@@ -2,7 +2,7 @@ error[E0382]: use of moved value
   --> $DIR/borrowck-move-and-move.rs:11:9
    |
 LL |     let a @ b = U;
-   |         ^^^^-   - move occurs because value has type `U`, which does not implement the `Copy` trait
+   |         ^   -   - move occurs because value has type `U`, which does not implement the `Copy` trait
    |         |   |
    |         |   value moved here
    |         value used here after move
@@ -11,9 +11,8 @@ error[E0382]: use of partially moved value
   --> $DIR/borrowck-move-and-move.rs:13:9
    |
 LL |     let a @ (b, c) = (U, U);
-   |         ^^^^^^^^-^
-   |         |       |
-   |         |       value partially moved here
+   |         ^       - value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -22,9 +21,8 @@ error[E0382]: use of partially moved value
   --> $DIR/borrowck-move-and-move.rs:15:9
    |
 LL |     let a @ (b, c) = (u(), u());
-   |         ^^^^^^^^-^
-   |         |       |
-   |         |       value partially moved here
+   |         ^       - value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -35,9 +33,8 @@ error[E0382]: use of moved value
 LL |     match Ok(U) {
    |           ----- move occurs because value has type `Result<U, U>`, which does not implement the `Copy` trait
 LL |         a @ Ok(b) | a @ Err(b) => {}
-   |         -------^-
-   |         |      |
-   |         |      value used here after move
+   |         -      ^ value used here after move
+   |         |
    |         value moved here
 
 error[E0382]: use of moved value
@@ -46,18 +43,16 @@ error[E0382]: use of moved value
 LL |     match Ok(U) {
    |           ----- move occurs because value has type `Result<U, U>`, which does not implement the `Copy` trait
 LL |         a @ Ok(b) | a @ Err(b) => {}
-   |                     --------^-
-   |                     |       |
-   |                     |       value used here after move
+   |                     -       ^ value used here after move
+   |                     |
    |                     value moved here
 
 error[E0382]: use of partially moved value
   --> $DIR/borrowck-move-and-move.rs:25:9
    |
 LL |         xs @ [a, .., b] => {}
-   |         ^^^^^^^^^^^^^-^
-   |         |            |
-   |         |            value partially moved here
+   |         ^^           - value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -66,9 +61,8 @@ error[E0382]: use of partially moved value
   --> $DIR/borrowck-move-and-move.rs:29:9
    |
 LL |         xs @ [_, ys @ .., _] => {}
-   |         ^^^^^^^^^-------^^^^
-   |         |        |
-   |         |        value partially moved here
+   |         ^^       -- value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -77,9 +71,8 @@ error[E0382]: use of moved value
   --> $DIR/borrowck-move-and-move.rs:22:12
    |
 LL |     fn fun(a @ b: U) {}
-   |            ^^^^-
-   |            |   |
-   |            |   value moved here
+   |            ^   - value moved here
+   |            |
    |            value used here after move
    |            move occurs because value has type `U`, which does not implement the `Copy` trait
 
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-pat-at-and-box.stderr b/src/test/ui/pattern/bindings-after-at/borrowck-pat-at-and-box.stderr
index 4b2048855ebb..002c7609f610 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-pat-at-and-box.stderr
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-pat-at-and-box.stderr
@@ -74,9 +74,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-at-and-box.rs:31:9
    |
 LL |     let ref a @ box b = Box::new(NC);
-   |         ^^^^^^^^^^^^-
-   |         |           |
-   |         |           value moved here
+   |         ^^^^^       - value moved here
+   |         |
    |         value borrowed here after move
    |
    = note: move occurs because value has type `NC`, which does not implement the `Copy` trait
@@ -85,9 +84,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-at-and-box.rs:38:9
    |
 LL |     let ref a @ box ref mut b = Box::new(NC);
-   |         ^^^^^^^^^^^^---------
-   |         |           |
-   |         |           mutable borrow occurs here
+   |         ^^^^^       --------- mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 ...
 LL |     *b = NC;
@@ -97,9 +95,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-at-and-box.rs:42:9
    |
 LL |     let ref a @ box ref mut b = Box::new(NC);
-   |         ^^^^^^^^^^^^---------
-   |         |           |
-   |         |           mutable borrow occurs here
+   |         ^^^^^       --------- mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 ...
 LL |     *b = NC;
@@ -109,9 +106,8 @@ error[E0502]: cannot borrow value as mutable because it is also borrowed as immu
   --> $DIR/borrowck-pat-at-and-box.rs:48:9
    |
 LL |     let ref mut a @ box ref b = Box::new(NC);
-   |         ^^^^^^^^^^^^^^^^-----
-   |         |               |
-   |         |               immutable borrow occurs here
+   |         ^^^^^^^^^       ----- immutable borrow occurs here
+   |         |
    |         mutable borrow occurs here
 ...
 LL |     drop(b);
@@ -121,9 +117,8 @@ error[E0502]: cannot borrow value as mutable because it is also borrowed as immu
   --> $DIR/borrowck-pat-at-and-box.rs:62:9
    |
 LL |         ref mut a @ box ref b => {
-   |         ^^^^^^^^^^^^^^^^-----
-   |         |               |
-   |         |               immutable borrow occurs here
+   |         ^^^^^^^^^       ----- immutable borrow occurs here
+   |         |
    |         mutable borrow occurs here
 ...
 LL |             drop(b);
@@ -133,9 +128,8 @@ error[E0502]: cannot borrow value as mutable because it is also borrowed as immu
   --> $DIR/borrowck-pat-at-and-box.rs:54:11
    |
 LL |     fn f5(ref mut a @ box ref b: Box<NC>) {
-   |           ^^^^^^^^^^^^^^^^-----
-   |           |               |
-   |           |               immutable borrow occurs here
+   |           ^^^^^^^^^       ----- immutable borrow occurs here
+   |           |
    |           mutable borrow occurs here
 ...
 LL |         drop(b);
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse.stderr b/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse.stderr
index bc2c1625fd0e..a9e66de08424 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse.stderr
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref-inverse.stderr
@@ -262,9 +262,8 @@ error[E0382]: use of partially moved value
   --> $DIR/borrowck-pat-by-move-and-ref-inverse.rs:24:9
    |
 LL |     let a @ (mut b @ ref mut c, d @ ref e) = (U, U);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^---------^
-   |         |                       |
-   |         |                       value partially moved here
+   |         ^                       - value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -273,9 +272,8 @@ error[E0382]: use of partially moved value
   --> $DIR/borrowck-pat-by-move-and-ref-inverse.rs:33:9
    |
 LL |     let a @ (mut b @ ref mut c, d @ ref e) = (u(), u());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^---------^
-   |         |                       |
-   |         |                       value partially moved here
+   |         ^                       - value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -286,10 +284,7 @@ error[E0382]: use of moved value
 LL |     match Some((U, U)) {
    |           ------------ move occurs because value has type `Option<(U, U)>`, which does not implement the `Copy` trait
 LL |         a @ Some((mut b @ ref mut c, d @ ref e)) => {}
-   |         -----------------------------^^^^^^^^^--
-   |         |                            |
-   |         |                            value used here after move
-   |         value moved here
+   |         - value moved here           ^ value used here after move
 
 error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref-inverse.rs:55:30
@@ -297,9 +292,8 @@ error[E0382]: borrow of moved value
 LL |     match Some([U, U]) {
    |           ------------ move occurs because value has type `Option<[U; 2]>`, which does not implement the `Copy` trait
 LL |         mut a @ Some([ref b, ref mut c]) => {}
-   |         ---------------------^^^^^^^^^--
-   |         |                    |
-   |         |                    value borrowed here after move
+   |         -----                ^^^^^^^^^ value borrowed here after move
+   |         |
    |         value moved here
 
 error[E0382]: borrow of moved value
@@ -308,9 +302,8 @@ error[E0382]: borrow of moved value
 LL |     match Some(u()) {
    |           --------- move occurs because value has type `Option<U>`, which does not implement the `Copy` trait
 LL |         a @ Some(ref b) => {}
-   |         ---------^^^^^-
-   |         |        |
-   |         |        value borrowed here after move
+   |         -        ^^^^^ value borrowed here after move
+   |         |
    |         value moved here
 
 error[E0382]: use of moved value
@@ -319,10 +312,7 @@ error[E0382]: use of moved value
 LL |     match Some((u(), u())) {
    |           ---------------- move occurs because value has type `Option<(U, U)>`, which does not implement the `Copy` trait
 LL |         a @ Some((mut b @ ref mut c, d @ ref e)) => {}
-   |         -----------------------------^^^^^^^^^--
-   |         |                            |
-   |         |                            value used here after move
-   |         value moved here
+   |         - value moved here           ^ value used here after move
 
 error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref-inverse.rs:75:30
@@ -330,18 +320,16 @@ error[E0382]: borrow of moved value
 LL |     match Some([u(), u()]) {
    |           ---------------- move occurs because value has type `Option<[U; 2]>`, which does not implement the `Copy` trait
 LL |         mut a @ Some([ref b, ref mut c]) => {}
-   |         ---------------------^^^^^^^^^--
-   |         |                    |
-   |         |                    value borrowed here after move
+   |         -----                ^^^^^^^^^ value borrowed here after move
+   |         |
    |         value moved here
 
 error[E0382]: use of partially moved value
   --> $DIR/borrowck-pat-by-move-and-ref-inverse.rs:14:11
    |
 LL |     fn f2(mut a @ (b @ ref c, mut d @ ref e): (U, U)) {}
-   |           ^^^^^^^^^^^^^^^^^^^^-------------^
-   |           |                   |
-   |           |                   value partially moved here
+   |           ^^^^^               ----- value partially moved here
+   |           |
    |           value used here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref.stderr b/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref.stderr
index c019aae3dfc9..b2f22fe86388 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref.stderr
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-pat-by-move-and-ref.stderr
@@ -237,9 +237,8 @@ error[E0382]: borrow of partially moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:30:9
    |
 LL |     let ref mut a @ [b, mut c] = [U, U];
-   |         ^^^^^^^^^^^^^^^^-----^
-   |         |               |
-   |         |               value partially moved here
+   |         ^^^^^^^^^       ----- value partially moved here
+   |         |
    |         value borrowed here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -248,7 +247,7 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:33:9
    |
 LL |     let ref a @ b = u();
-   |         ^^^^^^^^-   --- move occurs because value has type `U`, which does not implement the `Copy` trait
+   |         ^^^^^   -   --- move occurs because value has type `U`, which does not implement the `Copy` trait
    |         |       |
    |         |       value moved here
    |         value borrowed here after move
@@ -257,9 +256,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:36:18
    |
 LL |     let ref a @ (ref b @ mut c, ref d @ e) = (u(), u());
-   |                  ^^^^^^^^-----
-   |                  |       |
-   |                  |       value moved here
+   |                  ^^^^^   ----- value moved here
+   |                  |
    |                  value borrowed here after move
    |
    = note: move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -268,9 +266,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:36:33
    |
 LL |     let ref a @ (ref b @ mut c, ref d @ e) = (u(), u());
-   |                                 ^^^^^^^^-
-   |                                 |       |
-   |                                 |       value moved here
+   |                                 ^^^^^   - value moved here
+   |                                 |
    |                                 value borrowed here after move
    |
    = note: move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -279,9 +276,8 @@ error[E0382]: borrow of partially moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:42:9
    |
 LL |     let ref mut a @ [b, mut c] = [u(), u()];
-   |         ^^^^^^^^^^^^^^^^-----^
-   |         |               |
-   |         |               value partially moved here
+   |         ^^^^^^^^^       ----- value partially moved here
+   |         |
    |         value borrowed here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -290,9 +286,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:69:23
    |
 LL |         ref a @ Some((ref b @ mut c, ref d @ e)) => {}
-   |                       ^^^^^^^^-----
-   |                       |       |
-   |                       |       value moved here
+   |                       ^^^^^   ----- value moved here
+   |                       |
    |                       value borrowed here after move
    |
    = note: move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -305,9 +300,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:69:38
    |
 LL |         ref a @ Some((ref b @ mut c, ref d @ e)) => {}
-   |                                      ^^^^^^^^-
-   |                                      |       |
-   |                                      |       value moved here
+   |                                      ^^^^^   - value moved here
+   |                                      |
    |                                      value borrowed here after move
    |
    = note: move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -320,9 +314,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:11:11
    |
 LL |     fn f1(ref a @ b: U) {}
-   |           ^^^^^^^^-
-   |           |       |
-   |           |       value moved here
+   |           ^^^^^   - value moved here
+   |           |
    |           value borrowed here after move
    |           move occurs because value has type `U`, which does not implement the `Copy` trait
 
@@ -330,9 +323,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:14:20
    |
 LL |     fn f2(ref a @ (ref b @ mut c, ref d @ e): (U, U)) {}
-   |                    ^^^^^^^^-----
-   |                    |       |
-   |                    |       value moved here
+   |                    ^^^^^   ----- value moved here
+   |                    |
    |                    value borrowed here after move
    |
    = note: move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -341,9 +333,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:14:35
    |
 LL |     fn f2(ref a @ (ref b @ mut c, ref d @ e): (U, U)) {}
-   |                                   ^^^^^^^^-
-   |                                   |       |
-   |                                   |       value moved here
+   |                                   ^^^^^   - value moved here
+   |                                   |
    |                                   value borrowed here after move
    |
    = note: move occurs because value has type `U`, which does not implement the `Copy` trait
@@ -352,9 +343,8 @@ error[E0382]: borrow of partially moved value
   --> $DIR/borrowck-pat-by-move-and-ref.rs:20:11
    |
 LL |     fn f3(ref mut a @ [b, mut c]: [U; 2]) {}
-   |           ^^^^^^^^^^^^^^^^-----^
-   |           |               |
-   |           |               value partially moved here
+   |           ^^^^^^^^^       ----- value partially moved here
+   |           |
    |           value borrowed here after partial move
    |
    = note: partial move occurs because value has type `U`, which does not implement the `Copy` trait
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.stderr b/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.stderr
index 2ae78d1084e0..8546b4bb4773 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.stderr
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-and-ref.stderr
@@ -298,9 +298,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:8:31
    |
 LL |         ref mut z @ &mut Some(ref a) => {
-   |         ----------------------^^^^^-
-   |         |                     |
-   |         |                     immutable borrow occurs here
+   |         ---------             ^^^^^ immutable borrow occurs here
+   |         |
    |         mutable borrow occurs here
 ...
 LL |             **z = None;
@@ -310,9 +309,8 @@ error[E0502]: cannot borrow value as mutable because it is also borrowed as immu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:46:9
    |
 LL |     let ref mut a @ ref b = u();
-   |         ^^^^^^^^^^^^-----
-   |         |           |
-   |         |           immutable borrow occurs here
+   |         ^^^^^^^^^   ----- immutable borrow occurs here
+   |         |
    |         mutable borrow occurs here
 ...
 LL |     drop(b);
@@ -322,9 +320,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:51:9
    |
 LL |     let ref a @ ref mut b = u();
-   |         ^^^^^^^^---------
-   |         |       |
-   |         |       mutable borrow occurs here
+   |         ^^^^^   --------- mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 ...
 LL |     *b = u();
@@ -334,9 +331,8 @@ error[E0502]: cannot borrow value as mutable because it is also borrowed as immu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:76:20
    |
 LL |         ref a @ Ok(ref mut b) | ref a @ Err(ref mut b) => {
-   |         -----------^^^^^^^^^-
-   |         |          |
-   |         |          mutable borrow occurs here
+   |         -----      ^^^^^^^^^ mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 ...
 LL |             drop(a);
@@ -346,9 +342,8 @@ error[E0502]: cannot borrow value as mutable because it is also borrowed as immu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:76:45
    |
 LL |         ref a @ Ok(ref mut b) | ref a @ Err(ref mut b) => {
-   |                                 ------------^^^^^^^^^-
-   |                                 |           |
-   |                                 |           mutable borrow occurs here
+   |                                 -----       ^^^^^^^^^ mutable borrow occurs here
+   |                                 |
    |                                 immutable borrow occurs here
 ...
 LL |             drop(a);
@@ -406,9 +401,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:117:9
    |
 LL |     let ref a @ (ref mut b, ref mut c) = (U, U);
-   |         ^^^^^^^^^---------^^^^^^^^^^^^
-   |         |        |
-   |         |        mutable borrow occurs here
+   |         ^^^^^    --------- mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 ...
 LL |     *b = U;
@@ -418,9 +412,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:123:9
    |
 LL |     let ref a @ (ref mut b, ref mut c) = (U, U);
-   |         ^^^^^^^^^---------^^^^^^^^^^^^
-   |         |        |
-   |         |        mutable borrow occurs here
+   |         ^^^^^    --------- mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 ...
 LL |     *b = U;
@@ -430,9 +423,8 @@ error[E0502]: cannot borrow value as immutable because it is also borrowed as mu
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:129:9
    |
 LL |     let ref a @ (ref mut b, ref mut c) = (U, U);
-   |         ^^^^^^^^^---------^^^^^^^^^^^^
-   |         |        |
-   |         |        mutable borrow occurs here
+   |         ^^^^^    --------- mutable borrow occurs here
+   |         |
    |         immutable borrow occurs here
 LL |
 LL |     *b = U;
@@ -442,9 +434,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-ref-mut-and-ref.rs:28:30
    |
 LL |     fn f4_also_moved(ref a @ ref mut b @ c: U) {}
-   |                      --------^^^^^^^^^^^^-
-   |                      |       |           |
-   |                      |       |           value moved here
+   |                      -----   ^^^^^^^^^   - value moved here
+   |                      |       |
    |                      |       value borrowed here after move
    |                      move occurs because value has type `U`, which does not implement the `Copy` trait
 
diff --git a/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-twice.stderr b/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-twice.stderr
index aa02230419b5..384a57b2ee09 100644
--- a/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-twice.stderr
+++ b/src/test/ui/pattern/bindings-after-at/borrowck-pat-ref-mut-twice.stderr
@@ -262,9 +262,8 @@ error[E0499]: cannot borrow value as mutable more than once at a time
   --> $DIR/borrowck-pat-ref-mut-twice.rs:29:9
    |
 LL |     let ref mut a @ ref mut b = U;
-   |         ^^^^^^^^^^^^---------
-   |         |           |
-   |         |           first mutable borrow occurs here
+   |         ^^^^^^^^^   --------- first mutable borrow occurs here
+   |         |
    |         second mutable borrow occurs here
 ...
 LL |     drop(b);
@@ -274,9 +273,8 @@ error[E0499]: cannot borrow value as mutable more than once at a time
   --> $DIR/borrowck-pat-ref-mut-twice.rs:39:9
    |
 LL |     let ref mut a @ ref mut b = U;
-   |         ^^^^^^^^^^^^---------
-   |         |           |
-   |         |           first mutable borrow occurs here
+   |         ^^^^^^^^^   --------- first mutable borrow occurs here
+   |         |
    |         second mutable borrow occurs here
 ...
 LL |     *b = U;
@@ -286,9 +284,8 @@ error[E0499]: cannot borrow value as mutable more than once at a time
   --> $DIR/borrowck-pat-ref-mut-twice.rs:89:24
    |
 LL |         ref mut a @ Ok(ref mut b) | ref mut a @ Err(ref mut b) => {
-   |         ---------------^^^^^^^^^-
-   |         |              |
-   |         |              second mutable borrow occurs here
+   |         ---------      ^^^^^^^^^ second mutable borrow occurs here
+   |         |
    |         first mutable borrow occurs here
 ...
 LL |             *a = Err(U);
@@ -298,9 +295,8 @@ error[E0499]: cannot borrow value as mutable more than once at a time
   --> $DIR/borrowck-pat-ref-mut-twice.rs:89:53
    |
 LL |         ref mut a @ Ok(ref mut b) | ref mut a @ Err(ref mut b) => {
-   |                                     ----------------^^^^^^^^^-
-   |                                     |               |
-   |                                     |               second mutable borrow occurs here
+   |                                     ---------       ^^^^^^^^^ second mutable borrow occurs here
+   |                                     |
    |                                     first mutable borrow occurs here
 ...
 LL |             *a = Err(U);
@@ -310,9 +306,8 @@ error[E0499]: cannot borrow value as mutable more than once at a time
   --> $DIR/borrowck-pat-ref-mut-twice.rs:101:24
    |
 LL |         ref mut a @ Ok(ref mut b) | ref mut a @ Err(ref mut b) => {
-   |         ---------------^^^^^^^^^-
-   |         |              |
-   |         |              second mutable borrow occurs here
+   |         ---------      ^^^^^^^^^ second mutable borrow occurs here
+   |         |
    |         first mutable borrow occurs here
 ...
 LL |             drop(a);
@@ -322,9 +317,8 @@ error[E0499]: cannot borrow value as mutable more than once at a time
   --> $DIR/borrowck-pat-ref-mut-twice.rs:101:53
    |
 LL |         ref mut a @ Ok(ref mut b) | ref mut a @ Err(ref mut b) => {
-   |                                     ----------------^^^^^^^^^-
-   |                                     |               |
-   |                                     |               second mutable borrow occurs here
+   |                                     ---------       ^^^^^^^^^ second mutable borrow occurs here
+   |                                     |
    |                                     first mutable borrow occurs here
 ...
 LL |             drop(a);
@@ -334,9 +328,8 @@ error[E0382]: borrow of moved value
   --> $DIR/borrowck-pat-ref-mut-twice.rs:21:34
    |
 LL |     fn f4_also_moved(ref mut a @ ref mut b @ c: U) {}
-   |                      ------------^^^^^^^^^^^^-
-   |                      |           |           |
-   |                      |           |           value moved here
+   |                      ---------   ^^^^^^^^^   - value moved here
+   |                      |           |
    |                      |           value borrowed here after move
    |                      move occurs because value has type `U`, which does not implement the `Copy` trait
 
diff --git a/src/test/ui/pattern/bindings-after-at/copy-and-move-mixed.stderr b/src/test/ui/pattern/bindings-after-at/copy-and-move-mixed.stderr
index d290144b6155..cd3234952fa5 100644
--- a/src/test/ui/pattern/bindings-after-at/copy-and-move-mixed.stderr
+++ b/src/test/ui/pattern/bindings-after-at/copy-and-move-mixed.stderr
@@ -2,9 +2,8 @@ error[E0382]: use of partially moved value
   --> $DIR/copy-and-move-mixed.rs:12:9
    |
 LL |     let a @ NC(b, c @ NC(d, e)) = NC(C, NC(C, C));
-   |         ^^^^^^^^^^------------^
-   |         |         |
-   |         |         value partially moved here
+   |         ^         - value partially moved here
+   |         |
    |         value used here after partial move
    |
    = note: partial move occurs because value has type `NC<C, C>`, which does not implement the `Copy` trait
diff --git a/src/test/ui/pattern/bindings-after-at/default-binding-modes-both-sides-independent.stderr b/src/test/ui/pattern/bindings-after-at/default-binding-modes-both-sides-independent.stderr
index d78faa682b50..840a513d6c67 100644
--- a/src/test/ui/pattern/bindings-after-at/default-binding-modes-both-sides-independent.stderr
+++ b/src/test/ui/pattern/bindings-after-at/default-binding-modes-both-sides-independent.stderr
@@ -48,7 +48,7 @@ error[E0382]: borrow of moved value
   --> $DIR/default-binding-modes-both-sides-independent.rs:29:9
    |
 LL |     let ref mut a @ b = NotCopy;
-   |         ^^^^^^^^^^^^-   ------- move occurs because value has type `NotCopy`, which does not implement the `Copy` trait
+   |         ^^^^^^^^^   -   ------- move occurs because value has type `NotCopy`, which does not implement the `Copy` trait
    |         |           |
    |         |           value moved here
    |         value borrowed here after move
diff --git a/src/test/ui/pattern/bindings-after-at/nested-binding-modes-mut.stderr b/src/test/ui/pattern/bindings-after-at/nested-binding-modes-mut.stderr
index 3180bd0afc10..70beb5d42322 100644
--- a/src/test/ui/pattern/bindings-after-at/nested-binding-modes-mut.stderr
+++ b/src/test/ui/pattern/bindings-after-at/nested-binding-modes-mut.stderr
@@ -11,7 +11,7 @@ error[E0596]: cannot borrow `not_mut` as mutable, as it is not declared as mutab
   --> $DIR/nested-binding-modes-mut.rs:9:5
    |
 LL |     let not_mut @ mut is_mut = 42;
-   |         -------------------- help: consider changing this to be mutable: `mut not_mut`
+   |         ------- help: consider changing this to be mutable: `mut not_mut`
 LL |     &mut is_mut;
 LL |     &mut not_mut;
    |     ^^^^^^^^^^^^ cannot borrow as mutable
diff --git a/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr b/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr
index 5beca04d2859..bac2db6ce825 100644
--- a/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr
+++ b/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr
@@ -35,7 +35,7 @@ error[E0502]: cannot borrow `arr[..]` as mutable because it is also borrowed as
   --> $DIR/borrowck-move-ref-pattern.rs:13:16
    |
 LL |     let [ref _x0_hold, _x1, ref xs_hold @ ..] = arr;
-   |                             ---------------- immutable borrow occurs here
+   |                             ----------- immutable borrow occurs here
 ...
 LL |     let [_, _, ref mut _x2, _x3, mut _x4] = arr;
    |                ^^^^^^^^^^^ mutable borrow occurs here
@@ -47,7 +47,7 @@ error[E0505]: cannot move out of `arr[..]` because it is borrowed
   --> $DIR/borrowck-move-ref-pattern.rs:13:29
    |
 LL |     let [ref _x0_hold, _x1, ref xs_hold @ ..] = arr;
-   |                             ---------------- borrow of `arr[..]` occurs here
+   |                             ----------- borrow of `arr[..]` occurs here
 ...
 LL |     let [_, _, ref mut _x2, _x3, mut _x4] = arr;
    |                             ^^^ move out of `arr[..]` occurs here
@@ -59,7 +59,7 @@ error[E0505]: cannot move out of `arr[..]` because it is borrowed
   --> $DIR/borrowck-move-ref-pattern.rs:13:34
    |
 LL |     let [ref _x0_hold, _x1, ref xs_hold @ ..] = arr;
-   |                             ---------------- borrow of `arr[..]` occurs here
+   |                             ----------- borrow of `arr[..]` occurs here
 ...
 LL |     let [_, _, ref mut _x2, _x3, mut _x4] = arr;
    |                                  ^^^^^^^ move out of `arr[..]` occurs here
diff --git a/src/test/ui/pattern/rest-pat-semantic-disallowed.rs b/src/test/ui/pattern/rest-pat-semantic-disallowed.rs
index 84552f2e7331..156285e0f9fc 100644
--- a/src/test/ui/pattern/rest-pat-semantic-disallowed.rs
+++ b/src/test/ui/pattern/rest-pat-semantic-disallowed.rs
@@ -1,5 +1,5 @@
 // Here we test that rest patterns, i.e. `..`, are not allowed
-// outside of slice (+ ident patterns witin those), tuple,
+// outside of slice (+ ident patterns within those), tuple,
 // and tuple struct patterns and that duplicates are caught in these contexts.
 
 #![feature(box_patterns)]
diff --git a/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.rs b/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.rs
index d968c48fb1ab..5d4181a30f05 100644
--- a/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.rs
+++ b/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.rs
@@ -22,22 +22,22 @@ fn main() {
         HiddenEnum::A => {}
         HiddenEnum::C => {}
     }
-    //~^^^^ non-exhaustive patterns: `B` not covered
+    //~^^^^ non-exhaustive patterns: `HiddenEnum::B` not covered
 
     match HiddenEnum::A {
         HiddenEnum::A => {}
     }
-    //~^^^ non-exhaustive patterns: `B` and `_` not covered
+    //~^^^ non-exhaustive patterns: `HiddenEnum::B` and `_` not covered
 
     match None {
         None => {}
         Some(HiddenEnum::A) => {}
     }
-    //~^^^^ non-exhaustive patterns: `Some(B)` and `Some(_)` not covered
+    //~^^^^ non-exhaustive patterns: `Some(HiddenEnum::B)` and `Some(_)` not covered
 
     match InCrate::A {
         InCrate::A => {}
         InCrate::B => {}
     }
-    //~^^^^ non-exhaustive patterns: `C` not covered
+    //~^^^^ non-exhaustive patterns: `InCrate::C` not covered
 }
diff --git a/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.stderr b/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.stderr
index 643e734f9d4f..b450a9aeddf8 100644
--- a/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.stderr
+++ b/src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.stderr
@@ -16,11 +16,11 @@ LL ~         HiddenEnum::B => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `B` not covered
+error[E0004]: non-exhaustive patterns: `HiddenEnum::B` not covered
   --> $DIR/doc-hidden-non-exhaustive.rs:21:11
    |
 LL |     match HiddenEnum::A {
-   |           ^^^^^^^^^^^^^ pattern `B` not covered
+   |           ^^^^^^^^^^^^^ pattern `HiddenEnum::B` not covered
    |
 note: `HiddenEnum` defined here
   --> $DIR/auxiliary/hidden.rs:3:5
@@ -34,14 +34,14 @@ LL |     B,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         HiddenEnum::C => {}
-LL +         B => todo!()
+LL +         HiddenEnum::B => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `B` and `_` not covered
+error[E0004]: non-exhaustive patterns: `HiddenEnum::B` and `_` not covered
   --> $DIR/doc-hidden-non-exhaustive.rs:27:11
    |
 LL |     match HiddenEnum::A {
-   |           ^^^^^^^^^^^^^ patterns `B` and `_` not covered
+   |           ^^^^^^^^^^^^^ patterns `HiddenEnum::B` and `_` not covered
    |
 note: `HiddenEnum` defined here
   --> $DIR/auxiliary/hidden.rs:3:5
@@ -55,14 +55,14 @@ LL |     B,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         HiddenEnum::A => {}
-LL +         B | _ => todo!()
+LL +         HiddenEnum::B | _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Some(B)` and `Some(_)` not covered
+error[E0004]: non-exhaustive patterns: `Some(HiddenEnum::B)` and `Some(_)` not covered
   --> $DIR/doc-hidden-non-exhaustive.rs:32:11
    |
 LL |     match None {
-   |           ^^^^ patterns `Some(B)` and `Some(_)` not covered
+   |           ^^^^ patterns `Some(HiddenEnum::B)` and `Some(_)` not covered
    |
 note: `Option<HiddenEnum>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
@@ -76,14 +76,14 @@ LL |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         Some(HiddenEnum::A) => {}
-LL +         Some(B) | Some(_) => todo!()
+LL +         Some(HiddenEnum::B) | Some(_) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `C` not covered
+error[E0004]: non-exhaustive patterns: `InCrate::C` not covered
   --> $DIR/doc-hidden-non-exhaustive.rs:38:11
    |
 LL |     match InCrate::A {
-   |           ^^^^^^^^^^ pattern `C` not covered
+   |           ^^^^^^^^^^ pattern `InCrate::C` not covered
    |
 note: `InCrate` defined here
   --> $DIR/doc-hidden-non-exhaustive.rs:11:5
@@ -97,7 +97,7 @@ LL |     C,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         InCrate::B => {}
-LL +         C => todo!()
+LL +         InCrate::C => todo!()
    |
 
 error: aborting due to 5 previous errors
diff --git a/src/test/ui/pattern/usefulness/empty-match.exhaustive_patterns.stderr b/src/test/ui/pattern/usefulness/empty-match.exhaustive_patterns.stderr
index d31ee0dbd14e..5e12bc1d22f0 100644
--- a/src/test/ui/pattern/usefulness/empty-match.exhaustive_patterns.stderr
+++ b/src/test/ui/pattern/usefulness/empty-match.exhaustive_patterns.stderr
@@ -105,11 +105,11 @@ LL | union NonEmptyUnion2 {
    = note: the matched value is of type `NonEmptyUnion2`
    = help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum1::Foo(_)` not covered
   --> $DIR/empty-match.rs:83:20
    |
 LL |     match_no_arms!(NonEmptyEnum1::Foo(true));
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `Foo(_)` not covered
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyEnum1::Foo(_)` not covered
    |
 note: `NonEmptyEnum1` defined here
   --> $DIR/empty-match.rs:24:5
@@ -121,11 +121,11 @@ LL |     Foo(bool),
    = note: the matched value is of type `NonEmptyEnum1`
    = help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` and `Bar` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
   --> $DIR/empty-match.rs:84:20
    |
 LL |     match_no_arms!(NonEmptyEnum2::Foo(true));
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `Foo(_)` and `Bar` not covered
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
    |
 note: `NonEmptyEnum2` defined here
   --> $DIR/empty-match.rs:27:5
@@ -139,11 +139,11 @@ LL |     Bar,
    = note: the matched value is of type `NonEmptyEnum2`
    = help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or multiple match arms
 
-error[E0004]: non-exhaustive patterns: `V1`, `V2`, `V3` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
   --> $DIR/empty-match.rs:85:20
    |
 LL |     match_no_arms!(NonEmptyEnum5::V1);
-   |                    ^^^^^^^^^^^^^^^^^ patterns `V1`, `V2`, `V3` and 2 more not covered
+   |                    ^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
    |
 note: `NonEmptyEnum5` defined here
   --> $DIR/empty-match.rs:30:6
@@ -238,11 +238,11 @@ LL ~             _ if false => {}
 LL +             NonEmptyUnion2 { .. } => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum1::Foo(_)` not covered
   --> $DIR/empty-match.rs:92:24
    |
 LL |     match_guarded_arm!(NonEmptyEnum1::Foo(true));
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `Foo(_)` not covered
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyEnum1::Foo(_)` not covered
    |
 note: `NonEmptyEnum1` defined here
   --> $DIR/empty-match.rs:24:5
@@ -255,14 +255,14 @@ LL |     Foo(bool),
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~             _ if false => {}
-LL +             Foo(_) => todo!()
+LL +             NonEmptyEnum1::Foo(_) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` and `Bar` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
   --> $DIR/empty-match.rs:93:24
    |
 LL |     match_guarded_arm!(NonEmptyEnum2::Foo(true));
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `Foo(_)` and `Bar` not covered
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
    |
 note: `NonEmptyEnum2` defined here
   --> $DIR/empty-match.rs:27:5
@@ -277,14 +277,14 @@ LL |     Bar,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~             _ if false => {}
-LL +             Foo(_) | Bar => todo!()
+LL +             NonEmptyEnum2::Foo(_) | NonEmptyEnum2::Bar => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `V1`, `V2`, `V3` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
   --> $DIR/empty-match.rs:94:24
    |
 LL |     match_guarded_arm!(NonEmptyEnum5::V1);
-   |                        ^^^^^^^^^^^^^^^^^ patterns `V1`, `V2`, `V3` and 2 more not covered
+   |                        ^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
    |
 note: `NonEmptyEnum5` defined here
   --> $DIR/empty-match.rs:30:6
diff --git a/src/test/ui/pattern/usefulness/empty-match.normal.stderr b/src/test/ui/pattern/usefulness/empty-match.normal.stderr
index d31ee0dbd14e..5e12bc1d22f0 100644
--- a/src/test/ui/pattern/usefulness/empty-match.normal.stderr
+++ b/src/test/ui/pattern/usefulness/empty-match.normal.stderr
@@ -105,11 +105,11 @@ LL | union NonEmptyUnion2 {
    = note: the matched value is of type `NonEmptyUnion2`
    = help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum1::Foo(_)` not covered
   --> $DIR/empty-match.rs:83:20
    |
 LL |     match_no_arms!(NonEmptyEnum1::Foo(true));
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `Foo(_)` not covered
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyEnum1::Foo(_)` not covered
    |
 note: `NonEmptyEnum1` defined here
   --> $DIR/empty-match.rs:24:5
@@ -121,11 +121,11 @@ LL |     Foo(bool),
    = note: the matched value is of type `NonEmptyEnum1`
    = help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` and `Bar` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
   --> $DIR/empty-match.rs:84:20
    |
 LL |     match_no_arms!(NonEmptyEnum2::Foo(true));
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `Foo(_)` and `Bar` not covered
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
    |
 note: `NonEmptyEnum2` defined here
   --> $DIR/empty-match.rs:27:5
@@ -139,11 +139,11 @@ LL |     Bar,
    = note: the matched value is of type `NonEmptyEnum2`
    = help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or multiple match arms
 
-error[E0004]: non-exhaustive patterns: `V1`, `V2`, `V3` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
   --> $DIR/empty-match.rs:85:20
    |
 LL |     match_no_arms!(NonEmptyEnum5::V1);
-   |                    ^^^^^^^^^^^^^^^^^ patterns `V1`, `V2`, `V3` and 2 more not covered
+   |                    ^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
    |
 note: `NonEmptyEnum5` defined here
   --> $DIR/empty-match.rs:30:6
@@ -238,11 +238,11 @@ LL ~             _ if false => {}
 LL +             NonEmptyUnion2 { .. } => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum1::Foo(_)` not covered
   --> $DIR/empty-match.rs:92:24
    |
 LL |     match_guarded_arm!(NonEmptyEnum1::Foo(true));
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `Foo(_)` not covered
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyEnum1::Foo(_)` not covered
    |
 note: `NonEmptyEnum1` defined here
   --> $DIR/empty-match.rs:24:5
@@ -255,14 +255,14 @@ LL |     Foo(bool),
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~             _ if false => {}
-LL +             Foo(_) => todo!()
+LL +             NonEmptyEnum1::Foo(_) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Foo(_)` and `Bar` not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
   --> $DIR/empty-match.rs:93:24
    |
 LL |     match_guarded_arm!(NonEmptyEnum2::Foo(true));
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `Foo(_)` and `Bar` not covered
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
    |
 note: `NonEmptyEnum2` defined here
   --> $DIR/empty-match.rs:27:5
@@ -277,14 +277,14 @@ LL |     Bar,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~             _ if false => {}
-LL +             Foo(_) | Bar => todo!()
+LL +             NonEmptyEnum2::Foo(_) | NonEmptyEnum2::Bar => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `V1`, `V2`, `V3` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
   --> $DIR/empty-match.rs:94:24
    |
 LL |     match_guarded_arm!(NonEmptyEnum5::V1);
-   |                        ^^^^^^^^^^^^^^^^^ patterns `V1`, `V2`, `V3` and 2 more not covered
+   |                        ^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
    |
 note: `NonEmptyEnum5` defined here
   --> $DIR/empty-match.rs:30:6
diff --git a/src/test/ui/pattern/usefulness/empty-match.rs b/src/test/ui/pattern/usefulness/empty-match.rs
index 8110ec013d7c..9cdc0413ba10 100644
--- a/src/test/ui/pattern/usefulness/empty-match.rs
+++ b/src/test/ui/pattern/usefulness/empty-match.rs
@@ -80,16 +80,16 @@ fn main() {
     match_no_arms!(NonEmptyStruct2(true)); //~ ERROR type `NonEmptyStruct2` is non-empty
     match_no_arms!((NonEmptyUnion1 { foo: () })); //~ ERROR type `NonEmptyUnion1` is non-empty
     match_no_arms!((NonEmptyUnion2 { foo: () })); //~ ERROR type `NonEmptyUnion2` is non-empty
-    match_no_arms!(NonEmptyEnum1::Foo(true)); //~ ERROR `Foo(_)` not covered
-    match_no_arms!(NonEmptyEnum2::Foo(true)); //~ ERROR `Foo(_)` and `Bar` not covered
-    match_no_arms!(NonEmptyEnum5::V1); //~ ERROR `V1`, `V2`, `V3` and 2 more not covered
+    match_no_arms!(NonEmptyEnum1::Foo(true)); //~ ERROR `NonEmptyEnum1::Foo(_)` not covered
+    match_no_arms!(NonEmptyEnum2::Foo(true)); //~ ERROR `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
+    match_no_arms!(NonEmptyEnum5::V1); //~ ERROR `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
 
     match_guarded_arm!(0u8); //~ ERROR `_` not covered
     match_guarded_arm!(NonEmptyStruct1); //~ ERROR `NonEmptyStruct1` not covered
     match_guarded_arm!(NonEmptyStruct2(true)); //~ ERROR `NonEmptyStruct2(_)` not covered
     match_guarded_arm!((NonEmptyUnion1 { foo: () })); //~ ERROR `NonEmptyUnion1 { .. }` not covered
     match_guarded_arm!((NonEmptyUnion2 { foo: () })); //~ ERROR `NonEmptyUnion2 { .. }` not covered
-    match_guarded_arm!(NonEmptyEnum1::Foo(true)); //~ ERROR `Foo(_)` not covered
-    match_guarded_arm!(NonEmptyEnum2::Foo(true)); //~ ERROR `Foo(_)` and `Bar` not covered
-    match_guarded_arm!(NonEmptyEnum5::V1); //~ ERROR `V1`, `V2`, `V3` and 2 more not covered
+    match_guarded_arm!(NonEmptyEnum1::Foo(true)); //~ ERROR `NonEmptyEnum1::Foo(_)` not covered
+    match_guarded_arm!(NonEmptyEnum2::Foo(true)); //~ ERROR `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
+    match_guarded_arm!(NonEmptyEnum5::V1); //~ ERROR `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
 }
diff --git a/src/test/ui/pattern/usefulness/issue-15129.rs b/src/test/ui/pattern/usefulness/issue-15129.rs
index d2b72a86b74c..f02e5c0c6f8a 100644
--- a/src/test/ui/pattern/usefulness/issue-15129.rs
+++ b/src/test/ui/pattern/usefulness/issue-15129.rs
@@ -10,7 +10,7 @@ pub enum V {
 
 fn main() {
     match (T::T1(()), V::V2(true)) {
-        //~^ ERROR non-exhaustive patterns: `(T1(()), V2(_))` and `(T2(()), V1(_))` not covered
+        //~^ ERROR non-exhaustive patterns: `(T::T1(()), V::V2(_))` and `(T::T2(()), V::V1(_))` not covered
         (T::T1(()), V::V1(i)) => (),
         (T::T2(()), V::V2(b)) => (),
     }
diff --git a/src/test/ui/pattern/usefulness/issue-15129.stderr b/src/test/ui/pattern/usefulness/issue-15129.stderr
index af60f3ff50bf..ee8410b76508 100644
--- a/src/test/ui/pattern/usefulness/issue-15129.stderr
+++ b/src/test/ui/pattern/usefulness/issue-15129.stderr
@@ -1,14 +1,14 @@
-error[E0004]: non-exhaustive patterns: `(T1(()), V2(_))` and `(T2(()), V1(_))` not covered
+error[E0004]: non-exhaustive patterns: `(T::T1(()), V::V2(_))` and `(T::T2(()), V::V1(_))` not covered
   --> $DIR/issue-15129.rs:12:11
    |
 LL |     match (T::T1(()), V::V2(true)) {
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `(T1(()), V2(_))` and `(T2(()), V1(_))` not covered
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `(T::T1(()), V::V2(_))` and `(T::T2(()), V::V1(_))` not covered
    |
    = note: the matched value is of type `(T, V)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         (T::T2(()), V::V2(b)) => (),
-LL ~         (T1(()), V2(_)) | (T2(()), V1(_)) => todo!(),
+LL ~         (T::T1(()), V::V2(_)) | (T::T2(()), V::V1(_)) => todo!(),
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/pattern/usefulness/issue-31561.rs b/src/test/ui/pattern/usefulness/issue-31561.rs
index 813b2409cc8e..5b878851a314 100644
--- a/src/test/ui/pattern/usefulness/issue-31561.rs
+++ b/src/test/ui/pattern/usefulness/issue-31561.rs
@@ -6,5 +6,5 @@ enum Thing {
 
 fn main() {
     let Thing::Foo(y) = Thing::Foo(1);
-    //~^ ERROR refutable pattern in local binding: `Bar` and `Baz` not covered
+    //~^ ERROR refutable pattern in local binding: `Thing::Bar` and `Thing::Baz` not covered
 }
diff --git a/src/test/ui/pattern/usefulness/issue-31561.stderr b/src/test/ui/pattern/usefulness/issue-31561.stderr
index 9da6b5eeead2..20f2f09500aa 100644
--- a/src/test/ui/pattern/usefulness/issue-31561.stderr
+++ b/src/test/ui/pattern/usefulness/issue-31561.stderr
@@ -1,8 +1,8 @@
-error[E0005]: refutable pattern in local binding: `Bar` and `Baz` not covered
+error[E0005]: refutable pattern in local binding: `Thing::Bar` and `Thing::Baz` not covered
   --> $DIR/issue-31561.rs:8:9
    |
 LL |     let Thing::Foo(y) = Thing::Foo(1);
-   |         ^^^^^^^^^^^^^ patterns `Bar` and `Baz` not covered
+   |         ^^^^^^^^^^^^^ patterns `Thing::Bar` and `Thing::Baz` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -21,7 +21,7 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL |     let y = if let Thing::Foo(y) = Thing::Foo(1) { y } else { todo!() };
    |     ++++++++++                                   ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variants that aren't matched
+help: alternatively, you might want to use let else to handle the variants that aren't matched
    |
 LL |     let Thing::Foo(y) = Thing::Foo(1) else { todo!() };
    |                                       ++++++++++++++++
diff --git a/src/test/ui/pattern/usefulness/issue-35609.stderr b/src/test/ui/pattern/usefulness/issue-35609.stderr
index 2247b818d438..c9781d52e6dc 100644
--- a/src/test/ui/pattern/usefulness/issue-35609.stderr
+++ b/src/test/ui/pattern/usefulness/issue-35609.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `(B, _)`, `(C, _)`, `(D, _)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `(Enum::B, _)`, `(Enum::C, _)`, `(Enum::D, _)` and 2 more not covered
   --> $DIR/issue-35609.rs:10:11
    |
 LL |     match (A, ()) {
-   |           ^^^^^^^ patterns `(B, _)`, `(C, _)`, `(D, _)` and 2 more not covered
+   |           ^^^^^^^ patterns `(Enum::B, _)`, `(Enum::C, _)`, `(Enum::D, _)` and 2 more not covered
    |
    = note: the matched value is of type `(Enum, ())`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
@@ -11,11 +11,11 @@ LL ~         (A, _) => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `(_, B)`, `(_, C)`, `(_, D)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `(_, Enum::B)`, `(_, Enum::C)`, `(_, Enum::D)` and 2 more not covered
   --> $DIR/issue-35609.rs:14:11
    |
 LL |     match (A, A) {
-   |           ^^^^^^ patterns `(_, B)`, `(_, C)`, `(_, D)` and 2 more not covered
+   |           ^^^^^^ patterns `(_, Enum::B)`, `(_, Enum::C)`, `(_, Enum::D)` and 2 more not covered
    |
    = note: the matched value is of type `(Enum, Enum)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
@@ -24,11 +24,11 @@ LL ~         (_, A) => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `((B, _), _)`, `((C, _), _)`, `((D, _), _)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `((Enum::B, _), _)`, `((Enum::C, _), _)`, `((Enum::D, _), _)` and 2 more not covered
   --> $DIR/issue-35609.rs:18:11
    |
 LL |     match ((A, ()), ()) {
-   |           ^^^^^^^^^^^^^ patterns `((B, _), _)`, `((C, _), _)`, `((D, _), _)` and 2 more not covered
+   |           ^^^^^^^^^^^^^ patterns `((Enum::B, _), _)`, `((Enum::C, _), _)`, `((Enum::D, _), _)` and 2 more not covered
    |
    = note: the matched value is of type `((Enum, ()), ())`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
@@ -37,11 +37,11 @@ LL ~         ((A, ()), _) => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `((B, _), _)`, `((C, _), _)`, `((D, _), _)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `((Enum::B, _), _)`, `((Enum::C, _), _)`, `((Enum::D, _), _)` and 2 more not covered
   --> $DIR/issue-35609.rs:22:11
    |
 LL |     match ((A, ()), A) {
-   |           ^^^^^^^^^^^^ patterns `((B, _), _)`, `((C, _), _)`, `((D, _), _)` and 2 more not covered
+   |           ^^^^^^^^^^^^ patterns `((Enum::B, _), _)`, `((Enum::C, _), _)`, `((Enum::D, _), _)` and 2 more not covered
    |
    = note: the matched value is of type `((Enum, ()), Enum)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
@@ -50,11 +50,11 @@ LL ~         ((A, ()), _) => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `((B, _), _)`, `((C, _), _)`, `((D, _), _)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `((Enum::B, _), _)`, `((Enum::C, _), _)`, `((Enum::D, _), _)` and 2 more not covered
   --> $DIR/issue-35609.rs:26:11
    |
 LL |     match ((A, ()), ()) {
-   |           ^^^^^^^^^^^^^ patterns `((B, _), _)`, `((C, _), _)`, `((D, _), _)` and 2 more not covered
+   |           ^^^^^^^^^^^^^ patterns `((Enum::B, _), _)`, `((Enum::C, _), _)`, `((Enum::D, _), _)` and 2 more not covered
    |
    = note: the matched value is of type `((Enum, ()), ())`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
@@ -63,11 +63,11 @@ LL ~         ((A, _), _) => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `S(B, _)`, `S(C, _)`, `S(D, _)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `S(Enum::B, _)`, `S(Enum::C, _)`, `S(Enum::D, _)` and 2 more not covered
   --> $DIR/issue-35609.rs:31:11
    |
 LL |     match S(A, ()) {
-   |           ^^^^^^^^ patterns `S(B, _)`, `S(C, _)`, `S(D, _)` and 2 more not covered
+   |           ^^^^^^^^ patterns `S(Enum::B, _)`, `S(Enum::C, _)`, `S(Enum::D, _)` and 2 more not covered
    |
 note: `S` defined here
   --> $DIR/issue-35609.rs:6:8
@@ -81,11 +81,11 @@ LL ~         S(A, _) => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Sd { x: B, .. }`, `Sd { x: C, .. }`, `Sd { x: D, .. }` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `Sd { x: Enum::B, .. }`, `Sd { x: Enum::C, .. }`, `Sd { x: Enum::D, .. }` and 2 more not covered
   --> $DIR/issue-35609.rs:35:11
    |
 LL |     match (Sd { x: A, y: () }) {
-   |           ^^^^^^^^^^^^^^^^^^^^ patterns `Sd { x: B, .. }`, `Sd { x: C, .. }`, `Sd { x: D, .. }` and 2 more not covered
+   |           ^^^^^^^^^^^^^^^^^^^^ patterns `Sd { x: Enum::B, .. }`, `Sd { x: Enum::C, .. }`, `Sd { x: Enum::D, .. }` and 2 more not covered
    |
 note: `Sd` defined here
   --> $DIR/issue-35609.rs:7:8
@@ -99,11 +99,11 @@ LL ~         Sd { x: A, y: _ } => {}
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Some(B)`, `Some(C)`, `Some(D)` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `Some(Enum::B)`, `Some(Enum::C)`, `Some(Enum::D)` and 2 more not covered
   --> $DIR/issue-35609.rs:39:11
    |
 LL |     match Some(A) {
-   |           ^^^^^^^ patterns `Some(B)`, `Some(C)`, `Some(D)` and 2 more not covered
+   |           ^^^^^^^ patterns `Some(Enum::B)`, `Some(Enum::C)`, `Some(Enum::D)` and 2 more not covered
    |
 note: `Option<Enum>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
diff --git a/src/test/ui/pattern/usefulness/issue-39362.stderr b/src/test/ui/pattern/usefulness/issue-39362.stderr
index ca37af6fb809..b8b17918aef8 100644
--- a/src/test/ui/pattern/usefulness/issue-39362.stderr
+++ b/src/test/ui/pattern/usefulness/issue-39362.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `Bar { bar: C, .. }`, `Bar { bar: D, .. }`, `Bar { bar: E, .. }` and 1 more not covered
+error[E0004]: non-exhaustive patterns: `Foo::Bar { bar: Bar::C, .. }`, `Foo::Bar { bar: Bar::D, .. }`, `Foo::Bar { bar: Bar::E, .. }` and 1 more not covered
   --> $DIR/issue-39362.rs:10:11
    |
 LL |     match f {
-   |           ^ patterns `Bar { bar: C, .. }`, `Bar { bar: D, .. }`, `Bar { bar: E, .. }` and 1 more not covered
+   |           ^ patterns `Foo::Bar { bar: Bar::C, .. }`, `Foo::Bar { bar: Bar::D, .. }`, `Foo::Bar { bar: Bar::E, .. }` and 1 more not covered
    |
 note: `Foo` defined here
   --> $DIR/issue-39362.rs:2:5
diff --git a/src/test/ui/pattern/usefulness/issue-40221.stderr b/src/test/ui/pattern/usefulness/issue-40221.stderr
index c477e4353350..4973e42b0544 100644
--- a/src/test/ui/pattern/usefulness/issue-40221.stderr
+++ b/src/test/ui/pattern/usefulness/issue-40221.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `C(QA)` not covered
+error[E0004]: non-exhaustive patterns: `P::C(PC::QA)` not covered
   --> $DIR/issue-40221.rs:11:11
    |
 LL |     match proto {
-   |           ^^^^^ pattern `C(QA)` not covered
+   |           ^^^^^ pattern `P::C(PC::QA)` not covered
    |
 note: `P` defined here
   --> $DIR/issue-40221.rs:2:5
@@ -15,7 +15,7 @@ LL |     C(PC),
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         P::C(PC::Q) => (),
-LL ~         C(QA) => todo!(),
+LL ~         P::C(PC::QA) => todo!(),
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/pattern/usefulness/issue-50900.rs b/src/test/ui/pattern/usefulness/issue-50900.rs
index 27135af95758..9cc760e9a10d 100644
--- a/src/test/ui/pattern/usefulness/issue-50900.rs
+++ b/src/test/ui/pattern/usefulness/issue-50900.rs
@@ -13,7 +13,7 @@ impl Tag {
 
 fn main() {
     match Tag::ExifIFDPointer {
-    //~^ ERROR: non-exhaustive patterns: `Tag(Exif, _)` not covered
+    //~^ ERROR: non-exhaustive patterns: `Tag(Context::Exif, _)` not covered
         Tag::ExifIFDPointer => {}
     }
 }
diff --git a/src/test/ui/pattern/usefulness/issue-50900.stderr b/src/test/ui/pattern/usefulness/issue-50900.stderr
index 2bdbecabbbea..348246d28aac 100644
--- a/src/test/ui/pattern/usefulness/issue-50900.stderr
+++ b/src/test/ui/pattern/usefulness/issue-50900.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `Tag(Exif, _)` not covered
+error[E0004]: non-exhaustive patterns: `Tag(Context::Exif, _)` not covered
   --> $DIR/issue-50900.rs:15:11
    |
 LL |     match Tag::ExifIFDPointer {
-   |           ^^^^^^^^^^^^^^^^^^^ pattern `Tag(Exif, _)` not covered
+   |           ^^^^^^^^^^^^^^^^^^^ pattern `Tag(Context::Exif, _)` not covered
    |
 note: `Tag` defined here
   --> $DIR/issue-50900.rs:2:12
@@ -13,7 +13,7 @@ LL | pub struct Tag(pub Context, pub u16);
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Tag::ExifIFDPointer => {}
-LL +         Tag(Exif, _) => todo!()
+LL +         Tag(Context::Exif, _) => todo!()
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/pattern/usefulness/issue-56379.rs b/src/test/ui/pattern/usefulness/issue-56379.rs
index 9bccccca9c2b..097cf98d0126 100644
--- a/src/test/ui/pattern/usefulness/issue-56379.rs
+++ b/src/test/ui/pattern/usefulness/issue-56379.rs
@@ -6,7 +6,7 @@ enum Foo {
 
 fn main() {
     match Foo::A(true) {
-        //~^ ERROR non-exhaustive patterns: `A(false)`, `B(false)` and `C(false)` not covered
+        //~^ ERROR non-exhaustive patterns: `Foo::A(false)`, `Foo::B(false)` and `Foo::C(false)` not covered
         Foo::A(true) => {}
         Foo::B(true) => {}
         Foo::C(true) => {}
diff --git a/src/test/ui/pattern/usefulness/issue-56379.stderr b/src/test/ui/pattern/usefulness/issue-56379.stderr
index f6261001c5e0..6eed6bfae4c9 100644
--- a/src/test/ui/pattern/usefulness/issue-56379.stderr
+++ b/src/test/ui/pattern/usefulness/issue-56379.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `A(false)`, `B(false)` and `C(false)` not covered
+error[E0004]: non-exhaustive patterns: `Foo::A(false)`, `Foo::B(false)` and `Foo::C(false)` not covered
   --> $DIR/issue-56379.rs:8:11
    |
 LL |     match Foo::A(true) {
-   |           ^^^^^^^^^^^^ patterns `A(false)`, `B(false)` and `C(false)` not covered
+   |           ^^^^^^^^^^^^ patterns `Foo::A(false)`, `Foo::B(false)` and `Foo::C(false)` not covered
    |
 note: `Foo` defined here
   --> $DIR/issue-56379.rs:2:5
@@ -19,7 +19,7 @@ LL |     C(bool),
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         Foo::C(true) => {}
-LL +         A(false) | B(false) | C(false) => todo!()
+LL +         Foo::A(false) | Foo::B(false) | Foo::C(false) => todo!()
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/pattern/usefulness/issue-72377.rs b/src/test/ui/pattern/usefulness/issue-72377.rs
index b0d8a53ed93b..b5ad3075ca72 100644
--- a/src/test/ui/pattern/usefulness/issue-72377.rs
+++ b/src/test/ui/pattern/usefulness/issue-72377.rs
@@ -6,7 +6,7 @@ fn main() {
     let y = Some(X::A);
 
     match (x, y) {
-        //~^ ERROR non-exhaustive patterns: `(A, Some(A))`, `(A, Some(B))`, `(B, Some(B))` and 2
+        //~^ ERROR non-exhaustive patterns: `(X::A, Some(X::A))`, `(X::A, Some(X::B))`, `(X::B, Some(X::B))` and 2
         //~| more not covered
         (_, None) => false,
         (v, Some(w)) if v == w => true,
diff --git a/src/test/ui/pattern/usefulness/issue-72377.stderr b/src/test/ui/pattern/usefulness/issue-72377.stderr
index 20f002dd3db1..123dd051d249 100644
--- a/src/test/ui/pattern/usefulness/issue-72377.stderr
+++ b/src/test/ui/pattern/usefulness/issue-72377.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `(A, Some(A))`, `(A, Some(B))`, `(B, Some(B))` and 2 more not covered
+error[E0004]: non-exhaustive patterns: `(X::A, Some(X::A))`, `(X::A, Some(X::B))`, `(X::B, Some(X::B))` and 2 more not covered
   --> $DIR/issue-72377.rs:8:11
    |
 LL |     match (x, y) {
-   |           ^^^^^^ patterns `(A, Some(A))`, `(A, Some(B))`, `(B, Some(B))` and 2 more not covered
+   |           ^^^^^^ patterns `(X::A, Some(X::A))`, `(X::A, Some(X::B))`, `(X::B, Some(X::B))` and 2 more not covered
    |
    = note: the matched value is of type `(X, Option<X>)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
diff --git a/src/test/ui/pattern/usefulness/match-arm-statics-2.rs b/src/test/ui/pattern/usefulness/match-arm-statics-2.rs
index 4c5f2d356491..3c9c16561c02 100644
--- a/src/test/ui/pattern/usefulness/match-arm-statics-2.rs
+++ b/src/test/ui/pattern/usefulness/match-arm-statics-2.rs
@@ -27,7 +27,7 @@ const EAST: Direction = East;
 
 fn nonexhaustive_2() {
     match Some(Some(North)) {
-    //~^ ERROR non-exhaustive patterns: `Some(Some(West))` not covered
+    //~^ ERROR non-exhaustive patterns: `Some(Some(Direction::West))` not covered
         Some(NONE) => (),
         Some(Some(North)) => (),
         Some(Some(EAST)) => (),
@@ -46,7 +46,7 @@ const STATIC_FOO: Foo = Foo { bar: None, baz: NEW_FALSE };
 
 fn nonexhaustive_3() {
     match (Foo { bar: Some(North), baz: NewBool(true) }) {
-    //~^ ERROR non-exhaustive patterns: `Foo { bar: Some(North), baz: NewBool(true) }`
+    //~^ ERROR non-exhaustive patterns: `Foo { bar: Some(Direction::North), baz: NewBool(true) }`
         Foo { bar: None, baz: NewBool(true) } => (),
         Foo { bar: _, baz: NEW_FALSE } => (),
         Foo { bar: Some(West), baz: NewBool(true) } => (),
diff --git a/src/test/ui/pattern/usefulness/match-arm-statics-2.stderr b/src/test/ui/pattern/usefulness/match-arm-statics-2.stderr
index a2b66f5ed675..b0d7fe5eb689 100644
--- a/src/test/ui/pattern/usefulness/match-arm-statics-2.stderr
+++ b/src/test/ui/pattern/usefulness/match-arm-statics-2.stderr
@@ -11,11 +11,11 @@ LL ~         (false, true) => (),
 LL +         (true, false) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Some(Some(West))` not covered
+error[E0004]: non-exhaustive patterns: `Some(Some(Direction::West))` not covered
   --> $DIR/match-arm-statics-2.rs:29:11
    |
 LL |     match Some(Some(North)) {
-   |           ^^^^^^^^^^^^^^^^^ pattern `Some(Some(West))` not covered
+   |           ^^^^^^^^^^^^^^^^^ pattern `Some(Some(Direction::West))` not covered
    |
 note: `Option<Option<Direction>>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
@@ -32,14 +32,14 @@ LL |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         None => (),
-LL +         Some(Some(West)) => todo!()
+LL +         Some(Some(Direction::West)) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Foo { bar: Some(North), baz: NewBool(true) }` not covered
+error[E0004]: non-exhaustive patterns: `Foo { bar: Some(Direction::North), baz: NewBool(true) }` not covered
   --> $DIR/match-arm-statics-2.rs:48:11
    |
 LL |     match (Foo { bar: Some(North), baz: NewBool(true) }) {
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pattern `Foo { bar: Some(North), baz: NewBool(true) }` not covered
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pattern `Foo { bar: Some(Direction::North), baz: NewBool(true) }` not covered
    |
 note: `Foo` defined here
   --> $DIR/match-arm-statics-2.rs:40:8
@@ -50,7 +50,7 @@ LL | struct Foo {
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Foo { bar: Some(EAST), .. } => (),
-LL +         Foo { bar: Some(North), baz: NewBool(true) } => todo!()
+LL +         Foo { bar: Some(Direction::North), baz: NewBool(true) } => todo!()
    |
 
 error: aborting due to 3 previous errors
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.rs b/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.rs
index 2e15bc2d2a5f..af42fc1aeb46 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.rs
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.rs
@@ -35,43 +35,43 @@ enum E {
 
 fn by_val(e: E) {
     let e1 = e.clone();
-    match e1 { //~ ERROR non-exhaustive patterns: `B` and `C` not covered
-        //~^ NOTE patterns `B` and `C` not covered
+    match e1 { //~ ERROR non-exhaustive patterns: `E::B` and `E::C` not covered
+        //~^ NOTE patterns `E::B` and `E::C` not covered
         //~| NOTE the matched value is of type `E`
         E::A => {}
     }
 
-    let E::A = e; //~ ERROR refutable pattern in local binding: `B` and `C` not covered
-    //~^ NOTE patterns `B` and `C` not covered
+    let E::A = e; //~ ERROR refutable pattern in local binding: `E::B` and `E::C` not covered
+    //~^ NOTE patterns `E::B` and `E::C` not covered
     //~| NOTE `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with
     //~| NOTE for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
     //~| NOTE the matched value is of type `E`
 }
 
 fn by_ref_once(e: &E) {
-    match e { //~ ERROR non-exhaustive patterns: `&B` and `&C` not covered
-    //~^ NOTE patterns `&B` and `&C` not covered
+    match e { //~ ERROR non-exhaustive patterns: `&E::B` and `&E::C` not covered
+    //~^ NOTE patterns `&E::B` and `&E::C` not covered
     //~| NOTE the matched value is of type `&E`
         E::A => {}
     }
 
-    let E::A = e; //~ ERROR refutable pattern in local binding: `&B` and `&C` not covered
-    //~^ NOTE patterns `&B` and `&C` not covered
+    let E::A = e; //~ ERROR refutable pattern in local binding: `&E::B` and `&E::C` not covered
+    //~^ NOTE patterns `&E::B` and `&E::C` not covered
     //~| NOTE `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with
     //~| NOTE for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
     //~| NOTE the matched value is of type `&E`
 }
 
 fn by_ref_thrice(e: & &mut &E) {
-    match e { //~ ERROR non-exhaustive patterns: `&&mut &B` and `&&mut &C` not covered
-    //~^ NOTE patterns `&&mut &B` and `&&mut &C` not covered
+    match e { //~ ERROR non-exhaustive patterns: `&&mut &E::B` and `&&mut &E::C` not covered
+    //~^ NOTE patterns `&&mut &E::B` and `&&mut &E::C` not covered
     //~| NOTE the matched value is of type `&&mut &E`
         E::A => {}
     }
 
     let E::A = e;
-    //~^ ERROR refutable pattern in local binding: `&&mut &B` and `&&mut &C` not covered
-    //~| NOTE patterns `&&mut &B` and `&&mut &C` not covered
+    //~^ ERROR refutable pattern in local binding: `&&mut &E::B` and `&&mut &E::C` not covered
+    //~| NOTE patterns `&&mut &E::B` and `&&mut &E::C` not covered
     //~| NOTE `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with
     //~| NOTE for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
     //~| NOTE the matched value is of type `&&mut &E`
@@ -89,15 +89,15 @@ enum Opt {
 }
 
 fn ref_pat(e: Opt) {
-    match e {//~ ERROR non-exhaustive patterns: `None` not covered
-        //~^ NOTE pattern `None` not covered
+    match e {//~ ERROR non-exhaustive patterns: `Opt::None` not covered
+        //~^ NOTE pattern `Opt::None` not covered
         //~| NOTE the matched value is of type `Opt`
         Opt::Some(ref _x) => {}
     }
 
-    let Opt::Some(ref _x) = e; //~ ERROR refutable pattern in local binding: `None` not covered
+    let Opt::Some(ref _x) = e; //~ ERROR refutable pattern in local binding: `Opt::None` not covered
     //~^ NOTE the matched value is of type `Opt`
-    //~| NOTE pattern `None` not covered
+    //~| NOTE pattern `Opt::None` not covered
     //~| NOTE `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with
     //~| NOTE for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
 }
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr b/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr
index 0f06c31c468b..678c9b2ab58c 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `B` and `C` not covered
+error[E0004]: non-exhaustive patterns: `E::B` and `E::C` not covered
   --> $DIR/non-exhaustive-defined-here.rs:38:11
    |
 LL |     match e1 {
-   |           ^^ patterns `B` and `C` not covered
+   |           ^^ patterns `E::B` and `E::C` not covered
    |
 note: `E` defined here
   --> $DIR/non-exhaustive-defined-here.rs:14:5
@@ -19,14 +19,14 @@ LL |     C
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         E::A => {}
-LL +         B | C => todo!()
+LL +         E::B | E::C => todo!()
    |
 
-error[E0005]: refutable pattern in local binding: `B` and `C` not covered
+error[E0005]: refutable pattern in local binding: `E::B` and `E::C` not covered
   --> $DIR/non-exhaustive-defined-here.rs:44:9
    |
 LL |     let E::A = e;
-   |         ^^^^ patterns `B` and `C` not covered
+   |         ^^^^ patterns `E::B` and `E::C` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -47,11 +47,11 @@ help: you might want to use `if let` to ignore the variants that aren't matched
 LL |     if let E::A = e { todo!() }
    |     ++              ~~~~~~~~~~~
 
-error[E0004]: non-exhaustive patterns: `&B` and `&C` not covered
+error[E0004]: non-exhaustive patterns: `&E::B` and `&E::C` not covered
   --> $DIR/non-exhaustive-defined-here.rs:52:11
    |
 LL |     match e {
-   |           ^ patterns `&B` and `&C` not covered
+   |           ^ patterns `&E::B` and `&E::C` not covered
    |
 note: `E` defined here
   --> $DIR/non-exhaustive-defined-here.rs:14:5
@@ -68,14 +68,14 @@ LL |     C
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         E::A => {}
-LL +         &B | &C => todo!()
+LL +         &E::B | &E::C => todo!()
    |
 
-error[E0005]: refutable pattern in local binding: `&B` and `&C` not covered
+error[E0005]: refutable pattern in local binding: `&E::B` and `&E::C` not covered
   --> $DIR/non-exhaustive-defined-here.rs:58:9
    |
 LL |     let E::A = e;
-   |         ^^^^ patterns `&B` and `&C` not covered
+   |         ^^^^ patterns `&E::B` and `&E::C` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -96,11 +96,11 @@ help: you might want to use `if let` to ignore the variants that aren't matched
 LL |     if let E::A = e { todo!() }
    |     ++              ~~~~~~~~~~~
 
-error[E0004]: non-exhaustive patterns: `&&mut &B` and `&&mut &C` not covered
+error[E0004]: non-exhaustive patterns: `&&mut &E::B` and `&&mut &E::C` not covered
   --> $DIR/non-exhaustive-defined-here.rs:66:11
    |
 LL |     match e {
-   |           ^ patterns `&&mut &B` and `&&mut &C` not covered
+   |           ^ patterns `&&mut &E::B` and `&&mut &E::C` not covered
    |
 note: `E` defined here
   --> $DIR/non-exhaustive-defined-here.rs:14:5
@@ -117,14 +117,14 @@ LL |     C
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         E::A => {}
-LL +         &&mut &B | &&mut &C => todo!()
+LL +         &&mut &E::B | &&mut &E::C => todo!()
    |
 
-error[E0005]: refutable pattern in local binding: `&&mut &B` and `&&mut &C` not covered
+error[E0005]: refutable pattern in local binding: `&&mut &E::B` and `&&mut &E::C` not covered
   --> $DIR/non-exhaustive-defined-here.rs:72:9
    |
 LL |     let E::A = e;
-   |         ^^^^ patterns `&&mut &B` and `&&mut &C` not covered
+   |         ^^^^ patterns `&&mut &E::B` and `&&mut &E::C` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -145,11 +145,11 @@ help: you might want to use `if let` to ignore the variants that aren't matched
 LL |     if let E::A = e { todo!() }
    |     ++              ~~~~~~~~~~~
 
-error[E0004]: non-exhaustive patterns: `None` not covered
+error[E0004]: non-exhaustive patterns: `Opt::None` not covered
   --> $DIR/non-exhaustive-defined-here.rs:92:11
    |
 LL |     match e {
-   |           ^ pattern `None` not covered
+   |           ^ pattern `Opt::None` not covered
    |
 note: `Opt` defined here
   --> $DIR/non-exhaustive-defined-here.rs:84:5
@@ -163,14 +163,14 @@ LL |     None,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Opt::Some(ref _x) => {}
-LL +         None => todo!()
+LL +         Opt::None => todo!()
    |
 
-error[E0005]: refutable pattern in local binding: `None` not covered
+error[E0005]: refutable pattern in local binding: `Opt::None` not covered
   --> $DIR/non-exhaustive-defined-here.rs:98:9
    |
 LL |     let Opt::Some(ref _x) = e;
-   |         ^^^^^^^^^^^^^^^^^ pattern `None` not covered
+   |         ^^^^^^^^^^^^^^^^^ pattern `Opt::None` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -187,7 +187,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let _x = if let Opt::Some(ref _x) = e { _x } else { todo!() };
    |     +++++++++++                           +++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Opt::Some(ref _x) = e else { todo!() };
    |                               ++++++++++++++++
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.rs b/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.rs
index d198144790be..69c3c76580a7 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.rs
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.rs
@@ -12,7 +12,7 @@ fn match_nested_vecs<'a, T>(l1: Option<&'a [T]>, l2: Result<&'a [T], ()>) -> &'s
 
 fn main() {
     let x = T::A(U::C);
-    match x { //~ ERROR non-exhaustive patterns: `A(C)` not covered
+    match x { //~ ERROR non-exhaustive patterns: `T::A(U::C)` not covered
         T::A(U::D) => { panic!("hello"); }
         T::B => { panic!("goodbye"); }
     }
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.stderr b/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.stderr
index cbbd544f943b..44f327421109 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.stderr
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-match-nested.stderr
@@ -11,11 +11,11 @@ LL ~         (None, Ok(&[_, _, ..])) => "None, Ok(at least two elements)",
 LL +         (Some(&[]), Err(_)) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `A(C)` not covered
+error[E0004]: non-exhaustive patterns: `T::A(U::C)` not covered
   --> $DIR/non-exhaustive-match-nested.rs:15:11
    |
 LL |     match x {
-   |           ^ pattern `A(C)` not covered
+   |           ^ pattern `T::A(U::C)` not covered
    |
 note: `T` defined here
   --> $DIR/non-exhaustive-match-nested.rs:1:10
@@ -26,7 +26,7 @@ LL | enum T { A(U), B }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         T::B => { panic!("goodbye"); }
-LL +         A(C) => todo!()
+LL +         T::A(U::C) => todo!()
    |
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-match.rs b/src/test/ui/pattern/usefulness/non-exhaustive-match.rs
index 4ff12aa2ff5e..1cb58b8cebef 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-match.rs
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-match.rs
@@ -4,7 +4,7 @@ enum T { A, B }
 
 fn main() {
     let x = T::A;
-    match x { T::B => { } } //~ ERROR non-exhaustive patterns: `A` not covered
+    match x { T::B => { } } //~ ERROR non-exhaustive patterns: `T::A` not covered
     match true { //~ ERROR non-exhaustive patterns: `false` not covered
       true => {}
     }
@@ -15,11 +15,11 @@ fn main() {
                       //  and `(_, _, 5_i32..=i32::MAX)` not covered
       (_, _, 4) => {}
     }
-    match (T::A, T::A) { //~ ERROR non-exhaustive patterns: `(A, A)` and `(B, B)` not covered
+    match (T::A, T::A) { //~ ERROR non-exhaustive patterns: `(T::A, T::A)` and `(T::B, T::B)` not covered
       (T::A, T::B) => {}
       (T::B, T::A) => {}
     }
-    match T::A { //~ ERROR non-exhaustive patterns: `B` not covered
+    match T::A { //~ ERROR non-exhaustive patterns: `T::B` not covered
       T::A => {}
     }
     // This is exhaustive, though the algorithm got it wrong at one point
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-match.stderr b/src/test/ui/pattern/usefulness/non-exhaustive-match.stderr
index f2362c316dfb..4234600d0d02 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-match.stderr
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-match.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `A` not covered
+error[E0004]: non-exhaustive patterns: `T::A` not covered
   --> $DIR/non-exhaustive-match.rs:7:11
    |
 LL |     match x { T::B => { } }
-   |           ^ pattern `A` not covered
+   |           ^ pattern `T::A` not covered
    |
 note: `T` defined here
   --> $DIR/non-exhaustive-match.rs:3:10
@@ -12,8 +12,8 @@ LL | enum T { A, B }
    = note: the matched value is of type `T`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL |     match x { T::B => { }, A => todo!() }
-   |                          ++++++++++++++
+LL |     match x { T::B => { }, T::A => todo!() }
+   |                          +++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `false` not covered
   --> $DIR/non-exhaustive-match.rs:8:11
@@ -62,24 +62,24 @@ LL ~       (_, _, 4) => {}
 LL +       (_, _, i32::MIN..=3_i32) | (_, _, 5_i32..=i32::MAX) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `(A, A)` and `(B, B)` not covered
+error[E0004]: non-exhaustive patterns: `(T::A, T::A)` and `(T::B, T::B)` not covered
   --> $DIR/non-exhaustive-match.rs:18:11
    |
 LL |     match (T::A, T::A) {
-   |           ^^^^^^^^^^^^ patterns `(A, A)` and `(B, B)` not covered
+   |           ^^^^^^^^^^^^ patterns `(T::A, T::A)` and `(T::B, T::B)` not covered
    |
    = note: the matched value is of type `(T, T)`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~       (T::B, T::A) => {}
-LL +       (A, A) | (B, B) => todo!()
+LL +       (T::A, T::A) | (T::B, T::B) => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `B` not covered
+error[E0004]: non-exhaustive patterns: `T::B` not covered
   --> $DIR/non-exhaustive-match.rs:22:11
    |
 LL |     match T::A {
-   |           ^^^^ pattern `B` not covered
+   |           ^^^^ pattern `T::B` not covered
    |
 note: `T` defined here
   --> $DIR/non-exhaustive-match.rs:3:13
@@ -90,7 +90,7 @@ LL | enum T { A, B }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~       T::A => {}
-LL +       B => todo!()
+LL +       T::B => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `[]` not covered
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.rs b/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.rs
index abb4ea8daf57..4bd34421922b 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.rs
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.rs
@@ -21,7 +21,7 @@ enum Color {
 
 fn enum_with_single_missing_variant() {
     match Color::Red {
-    //~^ ERROR non-exhaustive patterns: `Red` not covered
+    //~^ ERROR non-exhaustive patterns: `Color::Red` not covered
         Color::CustomRGBA { .. } => (),
         Color::Green => ()
     }
@@ -33,7 +33,7 @@ enum Direction {
 
 fn enum_with_multiple_missing_variants() {
     match Direction::North {
-    //~^ ERROR non-exhaustive patterns: `East`, `South` and `West` not covered
+    //~^ ERROR non-exhaustive patterns: `Direction::East`, `Direction::South` and `Direction::West` not covered
         Direction::North => ()
     }
 }
@@ -44,7 +44,7 @@ enum ExcessiveEnum {
 
 fn enum_with_excessive_missing_variants() {
     match ExcessiveEnum::First {
-    //~^ ERROR `Second`, `Third`, `Fourth` and 8 more not covered
+    //~^ ERROR `ExcessiveEnum::Second`, `ExcessiveEnum::Third`, `ExcessiveEnum::Fourth` and 8 more not covered
 
         ExcessiveEnum::First => ()
     }
@@ -52,7 +52,7 @@ fn enum_with_excessive_missing_variants() {
 
 fn enum_struct_variant() {
     match Color::Red {
-    //~^ ERROR non-exhaustive patterns: `CustomRGBA { a: true, .. }` not covered
+    //~^ ERROR non-exhaustive patterns: `Color::CustomRGBA { a: true, .. }` not covered
         Color::Red => (),
         Color::Green => (),
         Color::CustomRGBA { a: false, r: _, g: _, b: 0 } => (),
@@ -68,7 +68,7 @@ enum Enum {
 fn vectors_with_nested_enums() {
     let x: &'static [Enum] = &[Enum::First, Enum::Second(false)];
     match *x {
-    //~^ ERROR non-exhaustive patterns: `[Second(true), Second(false)]` not covered
+    //~^ ERROR non-exhaustive patterns: `[Enum::Second(true), Enum::Second(false)]` not covered
         [] => (),
         [_] => (),
         [Enum::First, _] => (),
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.stderr b/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.stderr
index b0cfd631fb07..b8af566de7c6 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.stderr
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-pattern-witness.stderr
@@ -16,11 +16,11 @@ LL ~         Foo { first: false, second: Some([1, 2, 3, 4]) } => (),
 LL +         Foo { first: false, second: Some([_, _, _, _]) } => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Red` not covered
+error[E0004]: non-exhaustive patterns: `Color::Red` not covered
   --> $DIR/non-exhaustive-pattern-witness.rs:23:11
    |
 LL |     match Color::Red {
-   |           ^^^^^^^^^^ pattern `Red` not covered
+   |           ^^^^^^^^^^ pattern `Color::Red` not covered
    |
 note: `Color` defined here
   --> $DIR/non-exhaustive-pattern-witness.rs:17:5
@@ -33,14 +33,14 @@ LL |     Red,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Color::Green => (),
-LL +         Red => todo!()
+LL +         Color::Red => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `East`, `South` and `West` not covered
+error[E0004]: non-exhaustive patterns: `Direction::East`, `Direction::South` and `Direction::West` not covered
   --> $DIR/non-exhaustive-pattern-witness.rs:35:11
    |
 LL |     match Direction::North {
-   |           ^^^^^^^^^^^^^^^^ patterns `East`, `South` and `West` not covered
+   |           ^^^^^^^^^^^^^^^^ patterns `Direction::East`, `Direction::South` and `Direction::West` not covered
    |
 note: `Direction` defined here
   --> $DIR/non-exhaustive-pattern-witness.rs:31:12
@@ -56,14 +56,14 @@ LL |     North, East, South, West
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         Direction::North => (),
-LL +         East | South | West => todo!()
+LL +         Direction::East | Direction::South | Direction::West => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `Second`, `Third`, `Fourth` and 8 more not covered
+error[E0004]: non-exhaustive patterns: `ExcessiveEnum::Second`, `ExcessiveEnum::Third`, `ExcessiveEnum::Fourth` and 8 more not covered
   --> $DIR/non-exhaustive-pattern-witness.rs:46:11
    |
 LL |     match ExcessiveEnum::First {
-   |           ^^^^^^^^^^^^^^^^^^^^ patterns `Second`, `Third`, `Fourth` and 8 more not covered
+   |           ^^^^^^^^^^^^^^^^^^^^ patterns `ExcessiveEnum::Second`, `ExcessiveEnum::Third`, `ExcessiveEnum::Fourth` and 8 more not covered
    |
 note: `ExcessiveEnum` defined here
   --> $DIR/non-exhaustive-pattern-witness.rs:41:6
@@ -77,11 +77,11 @@ LL ~         ExcessiveEnum::First => (),
 LL +         _ => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `CustomRGBA { a: true, .. }` not covered
+error[E0004]: non-exhaustive patterns: `Color::CustomRGBA { a: true, .. }` not covered
   --> $DIR/non-exhaustive-pattern-witness.rs:54:11
    |
 LL |     match Color::Red {
-   |           ^^^^^^^^^^ pattern `CustomRGBA { a: true, .. }` not covered
+   |           ^^^^^^^^^^ pattern `Color::CustomRGBA { a: true, .. }` not covered
    |
 note: `Color` defined here
   --> $DIR/non-exhaustive-pattern-witness.rs:19:5
@@ -95,20 +95,20 @@ LL |     CustomRGBA { a: bool, r: u8, g: u8, b: u8 }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         Color::CustomRGBA { a: false, r: _, g: _, b: _ } => (),
-LL +         CustomRGBA { a: true, .. } => todo!()
+LL +         Color::CustomRGBA { a: true, .. } => todo!()
    |
 
-error[E0004]: non-exhaustive patterns: `[Second(true), Second(false)]` not covered
+error[E0004]: non-exhaustive patterns: `[Enum::Second(true), Enum::Second(false)]` not covered
   --> $DIR/non-exhaustive-pattern-witness.rs:70:11
    |
 LL |     match *x {
-   |           ^^ pattern `[Second(true), Second(false)]` not covered
+   |           ^^ pattern `[Enum::Second(true), Enum::Second(false)]` not covered
    |
    = note: the matched value is of type `[Enum]`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         [_, _, ref tail @ .., _] => (),
-LL +         [Second(true), Second(false)] => todo!()
+LL +         [Enum::Second(true), Enum::Second(false)] => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `((), false)` not covered
diff --git a/src/test/ui/pattern/usefulness/stable-gated-patterns.rs b/src/test/ui/pattern/usefulness/stable-gated-patterns.rs
index ff1c472e24fd..03db01160dda 100644
--- a/src/test/ui/pattern/usefulness/stable-gated-patterns.rs
+++ b/src/test/ui/pattern/usefulness/stable-gated-patterns.rs
@@ -8,7 +8,7 @@ fn main() {
     match UnstableEnum::Stable {
         UnstableEnum::Stable => {}
     }
-    //~^^^ non-exhaustive patterns: `Stable2` and `_` not covered
+    //~^^^ non-exhaustive patterns: `UnstableEnum::Stable2` and `_` not covered
 
     match UnstableEnum::Stable {
         UnstableEnum::Stable => {}
diff --git a/src/test/ui/pattern/usefulness/stable-gated-patterns.stderr b/src/test/ui/pattern/usefulness/stable-gated-patterns.stderr
index 98c75953add8..7b8588a3c735 100644
--- a/src/test/ui/pattern/usefulness/stable-gated-patterns.stderr
+++ b/src/test/ui/pattern/usefulness/stable-gated-patterns.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `Stable2` and `_` not covered
+error[E0004]: non-exhaustive patterns: `UnstableEnum::Stable2` and `_` not covered
   --> $DIR/stable-gated-patterns.rs:8:11
    |
 LL |     match UnstableEnum::Stable {
-   |           ^^^^^^^^^^^^^^^^^^^^ patterns `Stable2` and `_` not covered
+   |           ^^^^^^^^^^^^^^^^^^^^ patterns `UnstableEnum::Stable2` and `_` not covered
    |
 note: `UnstableEnum` defined here
   --> $DIR/auxiliary/unstable.rs:9:5
@@ -16,7 +16,7 @@ LL |     Stable2,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~         UnstableEnum::Stable => {}
-LL +         Stable2 | _ => todo!()
+LL +         UnstableEnum::Stable2 | _ => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `_` not covered
diff --git a/src/test/ui/pattern/usefulness/struct-like-enum-nonexhaustive.stderr b/src/test/ui/pattern/usefulness/struct-like-enum-nonexhaustive.stderr
index 6127fad3f7d5..85c97be29d6d 100644
--- a/src/test/ui/pattern/usefulness/struct-like-enum-nonexhaustive.stderr
+++ b/src/test/ui/pattern/usefulness/struct-like-enum-nonexhaustive.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `B { x: Some(_) }` not covered
+error[E0004]: non-exhaustive patterns: `A::B { x: Some(_) }` not covered
   --> $DIR/struct-like-enum-nonexhaustive.rs:8:11
    |
 LL |     match x {
-   |           ^ pattern `B { x: Some(_) }` not covered
+   |           ^ pattern `A::B { x: Some(_) }` not covered
    |
 note: `A` defined here
   --> $DIR/struct-like-enum-nonexhaustive.rs:2:5
@@ -15,7 +15,7 @@ LL |     B { x: Option<isize> },
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         A::B { x: None } => {}
-LL +         B { x: Some(_) } => todo!()
+LL +         A::B { x: Some(_) } => todo!()
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/pattern/usefulness/top-level-alternation.rs b/src/test/ui/pattern/usefulness/top-level-alternation.rs
index 076de846129e..e8cd12ea4a2c 100644
--- a/src/test/ui/pattern/usefulness/top-level-alternation.rs
+++ b/src/test/ui/pattern/usefulness/top-level-alternation.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 #![deny(unreachable_patterns)]
 
 fn main() {
diff --git a/src/test/ui/pattern/usefulness/top-level-alternation.stderr b/src/test/ui/pattern/usefulness/top-level-alternation.stderr
index dd5936fdcc42..17fa951c5390 100644
--- a/src/test/ui/pattern/usefulness/top-level-alternation.stderr
+++ b/src/test/ui/pattern/usefulness/top-level-alternation.stderr
@@ -1,71 +1,71 @@
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:6:23
+  --> $DIR/top-level-alternation.rs:4:23
    |
 LL |     while let 0..=2 | 1 = 0 {}
    |                       ^
    |
 note: the lint level is defined here
-  --> $DIR/top-level-alternation.rs:3:9
+  --> $DIR/top-level-alternation.rs:1:9
    |
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:7:20
+  --> $DIR/top-level-alternation.rs:5:20
    |
 LL |     if let 0..=2 | 1 = 0 {}
    |                    ^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:11:15
+  --> $DIR/top-level-alternation.rs:9:15
    |
 LL |             | 0 => {}
    |               ^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:16:15
+  --> $DIR/top-level-alternation.rs:14:15
    |
 LL |             | Some(0) => {}
    |               ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:21:9
+  --> $DIR/top-level-alternation.rs:19:9
    |
 LL |         (0, 0) => {}
    |         ^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:41:9
+  --> $DIR/top-level-alternation.rs:39:9
    |
 LL |         _ => {}
    |         ^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:45:9
+  --> $DIR/top-level-alternation.rs:43:9
    |
 LL |         Some(_) => {}
    |         ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:46:9
+  --> $DIR/top-level-alternation.rs:44:9
    |
 LL |         None => {}
    |         ^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:51:9
+  --> $DIR/top-level-alternation.rs:49:9
    |
 LL |         None | Some(_) => {}
    |         ^^^^^^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:55:9
+  --> $DIR/top-level-alternation.rs:53:9
    |
 LL |         1..=2 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:58:14
+  --> $DIR/top-level-alternation.rs:56:14
    |
 LL |     let (0 | 0) = 0 else { return };
    |              ^
diff --git a/src/test/ui/pattern/usefulness/unstable-gated-patterns.rs b/src/test/ui/pattern/usefulness/unstable-gated-patterns.rs
index bdab327fd57a..7046555e0d2f 100644
--- a/src/test/ui/pattern/usefulness/unstable-gated-patterns.rs
+++ b/src/test/ui/pattern/usefulness/unstable-gated-patterns.rs
@@ -11,7 +11,7 @@ fn main() {
         UnstableEnum::Stable => {}
         UnstableEnum::Stable2 => {}
     }
-    //~^^^^ non-exhaustive patterns: `Unstable` not covered
+    //~^^^^ non-exhaustive patterns: `UnstableEnum::Unstable` not covered
 
     // Ok: all variants are explicitly matched
     match UnstableEnum::Stable {
diff --git a/src/test/ui/pattern/usefulness/unstable-gated-patterns.stderr b/src/test/ui/pattern/usefulness/unstable-gated-patterns.stderr
index f07a25ca89b2..6dc9a4058398 100644
--- a/src/test/ui/pattern/usefulness/unstable-gated-patterns.stderr
+++ b/src/test/ui/pattern/usefulness/unstable-gated-patterns.stderr
@@ -1,8 +1,8 @@
-error[E0004]: non-exhaustive patterns: `Unstable` not covered
+error[E0004]: non-exhaustive patterns: `UnstableEnum::Unstable` not covered
   --> $DIR/unstable-gated-patterns.rs:10:11
    |
 LL |     match UnstableEnum::Stable {
-   |           ^^^^^^^^^^^^^^^^^^^^ pattern `Unstable` not covered
+   |           ^^^^^^^^^^^^^^^^^^^^ pattern `UnstableEnum::Unstable` not covered
    |
 note: `UnstableEnum` defined here
   --> $DIR/auxiliary/unstable.rs:11:5
@@ -16,7 +16,7 @@ LL |     Unstable,
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
 LL ~         UnstableEnum::Stable2 => {}
-LL +         Unstable => todo!()
+LL +         UnstableEnum::Unstable => todo!()
    |
 
 error: aborting due to previous error
diff --git a/src/test/ui/polymorphization/predicates.stderr b/src/test/ui/polymorphization/predicates.stderr
index e5af1d7515f6..80bb2af25cc2 100644
--- a/src/test/ui/polymorphization/predicates.stderr
+++ b/src/test/ui/polymorphization/predicates.stderr
@@ -41,7 +41,7 @@ error: item has unused generic parameters
 LL | fn bar<I>() {
    |    ^^^ - generic parameter `I` is unused
 
-note: the above error was encountered while instantiating `fn foo::<std::slice::Iter<u32>, T>`
+note: the above error was encountered while instantiating `fn foo::<std::slice::Iter<'_, u32>, T>`
   --> $DIR/predicates.rs:86:5
    |
 LL |     foo(x.iter());
diff --git a/src/test/ui/privacy/access_levels.rs b/src/test/ui/privacy/access_levels.rs
new file mode 100644
index 000000000000..bf94d980678f
--- /dev/null
+++ b/src/test/ui/privacy/access_levels.rs
@@ -0,0 +1,75 @@
+#![feature(rustc_attrs)]
+
+#[rustc_effective_visibility]
+mod outer { //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+    #[rustc_effective_visibility]
+    pub mod inner1 { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+
+        #[rustc_effective_visibility]
+        extern "C" {} //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+
+        #[rustc_effective_visibility]
+        pub trait PubTrait { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            const A: i32; //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            type B; //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+        }
+
+        #[rustc_effective_visibility]
+        struct PrivStruct; //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+
+        #[rustc_effective_visibility]
+        pub union PubUnion { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            a: u8, //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+            #[rustc_effective_visibility]
+            pub b: u8, //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+        }
+
+        #[rustc_effective_visibility]
+        pub enum Enum { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            A( //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+                #[rustc_effective_visibility]
+                PubUnion,  //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            ),
+        }
+    }
+
+    #[rustc_effective_visibility]
+    macro_rules! none_macro { //~ Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+        () => {};
+    }
+
+    #[macro_export]
+    #[rustc_effective_visibility]
+    macro_rules! public_macro { //~ Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+        () => {};
+    }
+
+    #[rustc_effective_visibility]
+    pub struct ReachableStruct { //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+        #[rustc_effective_visibility]
+        pub a: u8, //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+    }
+}
+
+#[rustc_effective_visibility]
+pub use outer::inner1; //~ ERROR Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+
+pub fn foo() -> outer::ReachableStruct { outer::ReachableStruct {a: 0} }
+
+mod half_public_import {
+    #[rustc_effective_visibility]
+    pub type HalfPublicImport = u8; //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+    #[rustc_effective_visibility]
+    #[allow(non_upper_case_globals)]
+    pub(crate) const HalfPublicImport: u8 = 0; //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+}
+
+#[rustc_effective_visibility]
+pub use half_public_import::HalfPublicImport; //~ ERROR Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+                                              //~^ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+
+fn main() {}
diff --git a/src/test/ui/privacy/access_levels.stderr b/src/test/ui/privacy/access_levels.stderr
new file mode 100644
index 000000000000..81514d1fbab4
--- /dev/null
+++ b/src/test/ui/privacy/access_levels.stderr
@@ -0,0 +1,134 @@
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:4:1
+   |
+LL | mod outer {
+   | ^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:6:5
+   |
+LL |     pub mod inner1 {
+   |     ^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:9:9
+   |
+LL |         extern "C" {}
+   |         ^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:12:9
+   |
+LL |         pub trait PubTrait {
+   |         ^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:20:9
+   |
+LL |         struct PrivStruct;
+   |         ^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:23:9
+   |
+LL |         pub union PubUnion {
+   |         ^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:25:13
+   |
+LL |             a: u8,
+   |             ^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:27:13
+   |
+LL |             pub b: u8,
+   |             ^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:31:9
+   |
+LL |         pub enum Enum {
+   |         ^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:33:13
+   |
+LL |             A(
+   |             ^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:35:17
+   |
+LL |                 PubUnion,
+   |                 ^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:41:5
+   |
+LL |     macro_rules! none_macro {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:47:5
+   |
+LL |     macro_rules! public_macro {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:52:5
+   |
+LL |     pub struct ReachableStruct {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:54:9
+   |
+LL |         pub a: u8,
+   |         ^^^^^^^^^
+
+error: Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:59:9
+   |
+LL | pub use outer::inner1;
+   |         ^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:65:5
+   |
+LL |     pub type HalfPublicImport = u8;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:68:5
+   |
+LL |     pub(crate) const HalfPublicImport: u8 = 0;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:72:9
+   |
+LL | pub use half_public_import::HalfPublicImport;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:72:9
+   |
+LL | pub use half_public_import::HalfPublicImport;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:14:13
+   |
+LL |             const A: i32;
+   |             ^^^^^^^^^^^^
+
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:16:13
+   |
+LL |             type B;
+   |             ^^^^^^
+
+error: aborting due to 22 previous errors
+
diff --git a/src/test/ui/privacy/associated-item-privacy-inherent.rs b/src/test/ui/privacy/associated-item-privacy-inherent.rs
index c3ae920238f1..7b7c734a99a1 100644
--- a/src/test/ui/privacy/associated-item-privacy-inherent.rs
+++ b/src/test/ui/privacy/associated-item-privacy-inherent.rs
@@ -11,11 +11,11 @@ mod priv_nominal {
 
     pub macro mac() {
         let value = Pub::method;
-        //~^ ERROR type `for<'r> fn(&'r priv_nominal::Pub) {priv_nominal::Pub::method}` is private
+        //~^ ERROR type `for<'a> fn(&'a priv_nominal::Pub) {priv_nominal::Pub::method}` is private
         value;
-        //~^ ERROR type `for<'r> fn(&'r priv_nominal::Pub) {priv_nominal::Pub::method}` is private
+        //~^ ERROR type `for<'a> fn(&'a priv_nominal::Pub) {priv_nominal::Pub::method}` is private
         Pub.method();
-        //~^ ERROR type `for<'r> fn(&'r priv_nominal::Pub) {priv_nominal::Pub::method}` is private
+        //~^ ERROR type `for<'a> fn(&'a priv_nominal::Pub) {priv_nominal::Pub::method}` is private
         Pub::CONST;
         //~^ ERROR associated constant `CONST` is private
         // let _: Pub::AssocTy;
diff --git a/src/test/ui/privacy/associated-item-privacy-inherent.stderr b/src/test/ui/privacy/associated-item-privacy-inherent.stderr
index 4478e5c2aba5..f4d4ee459204 100644
--- a/src/test/ui/privacy/associated-item-privacy-inherent.stderr
+++ b/src/test/ui/privacy/associated-item-privacy-inherent.stderr
@@ -1,4 +1,4 @@
-error: type `for<'r> fn(&'r priv_nominal::Pub) {priv_nominal::Pub::method}` is private
+error: type `for<'a> fn(&'a priv_nominal::Pub) {priv_nominal::Pub::method}` is private
   --> $DIR/associated-item-privacy-inherent.rs:13:21
    |
 LL |         let value = Pub::method;
@@ -9,7 +9,7 @@ LL |     priv_nominal::mac!();
    |
    = note: this error originates in the macro `priv_nominal::mac` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: type `for<'r> fn(&'r priv_nominal::Pub) {priv_nominal::Pub::method}` is private
+error: type `for<'a> fn(&'a priv_nominal::Pub) {priv_nominal::Pub::method}` is private
   --> $DIR/associated-item-privacy-inherent.rs:15:9
    |
 LL |         value;
@@ -20,7 +20,7 @@ LL |     priv_nominal::mac!();
    |
    = note: this error originates in the macro `priv_nominal::mac` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: type `for<'r> fn(&'r priv_nominal::Pub) {priv_nominal::Pub::method}` is private
+error: type `for<'a> fn(&'a priv_nominal::Pub) {priv_nominal::Pub::method}` is private
   --> $DIR/associated-item-privacy-inherent.rs:17:13
    |
 LL |         Pub.method();
diff --git a/src/test/ui/privacy/associated-item-privacy-trait.rs b/src/test/ui/privacy/associated-item-privacy-trait.rs
index c07aeed99c74..ad9a5e15c4e6 100644
--- a/src/test/ui/privacy/associated-item-privacy-trait.rs
+++ b/src/test/ui/privacy/associated-item-privacy-trait.rs
@@ -13,11 +13,11 @@ mod priv_trait {
 
     pub macro mac() {
         let value = <Pub as PrivTr>::method;
-        //~^ ERROR type `for<'r> fn(&'r priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
+        //~^ ERROR type `for<'a> fn(&'a priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
         value;
-        //~^ ERROR type `for<'r> fn(&'r priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
+        //~^ ERROR type `for<'a> fn(&'a priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
         Pub.method();
-        //~^ ERROR type `for<'r> fn(&'r Self) {<Self as PrivTr>::method}` is private
+        //~^ ERROR type `for<'a> fn(&'a Self) {<Self as PrivTr>::method}` is private
         <Pub as PrivTr>::CONST;
         //~^ ERROR associated constant `<Pub as PrivTr>::CONST` is private
         let _: <Pub as PrivTr>::AssocTy;
diff --git a/src/test/ui/privacy/associated-item-privacy-trait.stderr b/src/test/ui/privacy/associated-item-privacy-trait.stderr
index 6095f5f42b86..c4be1a9d9a20 100644
--- a/src/test/ui/privacy/associated-item-privacy-trait.stderr
+++ b/src/test/ui/privacy/associated-item-privacy-trait.stderr
@@ -1,4 +1,4 @@
-error: type `for<'r> fn(&'r priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
+error: type `for<'a> fn(&'a priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
   --> $DIR/associated-item-privacy-trait.rs:15:21
    |
 LL |         let value = <Pub as PrivTr>::method;
@@ -9,7 +9,7 @@ LL |     priv_trait::mac!();
    |
    = note: this error originates in the macro `priv_trait::mac` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: type `for<'r> fn(&'r priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
+error: type `for<'a> fn(&'a priv_trait::Pub) {<priv_trait::Pub as PrivTr>::method}` is private
   --> $DIR/associated-item-privacy-trait.rs:17:9
    |
 LL |         value;
@@ -20,7 +20,7 @@ LL |     priv_trait::mac!();
    |
    = note: this error originates in the macro `priv_trait::mac` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: type `for<'r> fn(&'r Self) {<Self as PrivTr>::method}` is private
+error: type `for<'a> fn(&'a Self) {<Self as PrivTr>::method}` is private
   --> $DIR/associated-item-privacy-trait.rs:19:13
    |
 LL |         Pub.method();
diff --git a/src/test/ui/privacy/private-inferred-type-3.rs b/src/test/ui/privacy/private-inferred-type-3.rs
index 00f0a715a836..0337aedd0088 100644
--- a/src/test/ui/privacy/private-inferred-type-3.rs
+++ b/src/test/ui/privacy/private-inferred-type-3.rs
@@ -6,7 +6,7 @@
 // error-pattern:type `fn() {<u8 as ext::PrivTrait>::method}` is private
 // error-pattern:type `fn(u8) -> ext::PrivTupleStruct {ext::PrivTupleStruct}` is private
 // error-pattern:type `fn(u8) -> PubTupleStruct {PubTupleStruct}` is private
-// error-pattern:type `for<'r> fn(&'r Pub<u8>) {Pub::<u8>::priv_method}` is private
+// error-pattern:type `for<'a> fn(&'a Pub<u8>) {Pub::<u8>::priv_method}` is private
 
 #![feature(decl_macro)]
 
diff --git a/src/test/ui/privacy/private-inferred-type-3.stderr b/src/test/ui/privacy/private-inferred-type-3.stderr
index f9dd1c3d0350..00b61512de6b 100644
--- a/src/test/ui/privacy/private-inferred-type-3.stderr
+++ b/src/test/ui/privacy/private-inferred-type-3.stderr
@@ -46,7 +46,7 @@ LL |     ext::m!();
    |
    = note: this error originates in the macro `ext::m` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: type `for<'r> fn(&'r Pub<u8>) {Pub::<u8>::priv_method}` is private
+error: type `for<'a> fn(&'a Pub<u8>) {Pub::<u8>::priv_method}` is private
   --> $DIR/private-inferred-type-3.rs:16:5
    |
 LL |     ext::m!();
diff --git a/src/test/ui/privacy/private-inferred-type.rs b/src/test/ui/privacy/private-inferred-type.rs
index b083a3970d6b..e8743dd968fe 100644
--- a/src/test/ui/privacy/private-inferred-type.rs
+++ b/src/test/ui/privacy/private-inferred-type.rs
@@ -47,7 +47,7 @@ mod m {
         PubTupleStruct;
         //~^ ERROR type `fn(u8) -> PubTupleStruct {PubTupleStruct}` is private
         Pub(0u8).priv_method();
-        //~^ ERROR type `for<'r> fn(&'r Pub<u8>) {Pub::<u8>::priv_method}` is private
+        //~^ ERROR type `for<'a> fn(&'a Pub<u8>) {Pub::<u8>::priv_method}` is private
     }
 
     trait Trait {}
diff --git a/src/test/ui/privacy/private-inferred-type.stderr b/src/test/ui/privacy/private-inferred-type.stderr
index aecd8b58c831..fc3f9ab62bfa 100644
--- a/src/test/ui/privacy/private-inferred-type.stderr
+++ b/src/test/ui/privacy/private-inferred-type.stderr
@@ -161,7 +161,7 @@ LL |     m::m!();
    |
    = note: this error originates in the macro `m::m` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: type `for<'r> fn(&'r Pub<u8>) {Pub::<u8>::priv_method}` is private
+error: type `for<'a> fn(&'a Pub<u8>) {Pub::<u8>::priv_method}` is private
   --> $DIR/private-inferred-type.rs:49:18
    |
 LL |         Pub(0u8).priv_method();
diff --git a/src/test/ui/privacy/reachable-unnameable-items.rs b/src/test/ui/privacy/reachable-unnameable-items.rs
index 1c91541e6422..1babe011996b 100644
--- a/src/test/ui/privacy/reachable-unnameable-items.rs
+++ b/src/test/ui/privacy/reachable-unnameable-items.rs
@@ -1,5 +1,4 @@
 // run-pass
-// ignore-wasm32-bare compiled with panic=abort by default
 // needs-unwind
 // aux-build:reachable-unnameable-items.rs
 
diff --git a/src/test/ui/proc-macro/auxiliary/expand-expr.rs b/src/test/ui/proc-macro/auxiliary/expand-expr.rs
index 5463e79d74e0..1d6ef8a13610 100644
--- a/src/test/ui/proc-macro/auxiliary/expand-expr.rs
+++ b/src/test/ui/proc-macro/auxiliary/expand-expr.rs
@@ -80,13 +80,21 @@ fn assert_ts_eq(lhs: &TokenStream, rhs: &TokenStream) {
 pub fn expand_expr_is(input: TokenStream) -> TokenStream {
     let mut iter = input.into_iter();
     let mut expected_tts = Vec::new();
-    loop {
+    let comma = loop {
         match iter.next() {
-            Some(TokenTree::Punct(ref p)) if p.as_char() == ',' => break,
+            Some(TokenTree::Punct(p)) if p.as_char() == ',' => break p,
             Some(tt) => expected_tts.push(tt),
             None => panic!("expected comma"),
         }
-    }
+    };
+
+    // Make sure that `Ident` and `Literal` objects from this proc-macro's
+    // environment are not invalidated when `expand_expr` recursively invokes
+    // another macro by taking a local copy, and checking it after the fact.
+    let pre_expand_span = comma.span();
+    let pre_expand_ident = Ident::new("ident", comma.span());
+    let pre_expand_literal = Literal::string("literal");
+    let pre_expand_call_site = Span::call_site();
 
     let expected = expected_tts.into_iter().collect::<TokenStream>();
     let expanded = iter.collect::<TokenStream>().expand_expr().expect("expand_expr failed");
@@ -100,6 +108,15 @@ pub fn expand_expr_is(input: TokenStream) -> TokenStream {
     // Also compare the raw tts to make sure they line up.
     assert_ts_eq(&expected, &expanded);
 
+    assert!(comma.span().eq(&pre_expand_span), "pre-expansion span is still equal");
+    assert_eq!(pre_expand_ident.to_string(), "ident", "pre-expansion identifier is still valid");
+    assert_eq!(
+        pre_expand_literal.to_string(),
+        "\"literal\"",
+        "pre-expansion literal is still valid"
+    );
+    assert!(Span::call_site().eq(&pre_expand_call_site), "pre-expansion call-site is still equal");
+
     TokenStream::new()
 }
 
diff --git a/src/test/ui/proc-macro/crt-static.rs b/src/test/ui/proc-macro/crt-static.rs
index 8c1a9dc80265..6103acb7b6bd 100644
--- a/src/test/ui/proc-macro/crt-static.rs
+++ b/src/test/ui/proc-macro/crt-static.rs
@@ -9,7 +9,7 @@
 
 // FIXME: This don't work when crate-type is specified by attribute
 // `#![crate_type = "proc-macro"]`, not by `--crate-type=proc-macro`
-// command line flag. This is beacuse the list of `cfg` symbols is generated
+// command line flag. This is because the list of `cfg` symbols is generated
 // before attributes are parsed. See rustc_interface::util::add_configuration
 #[cfg(target_feature = "crt-static")]
 compile_error!("crt-static is enabled");
diff --git a/src/test/ui/proc-macro/dollar-crate-issue-101211.rs b/src/test/ui/proc-macro/dollar-crate-issue-101211.rs
new file mode 100644
index 000000000000..fc1acfd32d2f
--- /dev/null
+++ b/src/test/ui/proc-macro/dollar-crate-issue-101211.rs
@@ -0,0 +1,29 @@
+// check-pass
+// edition:2021
+// aux-build:test-macros.rs
+
+#![no_std] // Don't load unnecessary hygiene information from std
+extern crate std;
+
+#[macro_use]
+extern crate test_macros;
+
+macro_rules! foo {
+    ($($path:ident)::*) => (
+        test_macros::recollect!(
+            $($path)::*
+        )
+    )
+}
+
+macro_rules! baz {
+    () => (
+        foo!($crate::BAR)
+    )
+}
+
+pub const BAR: u32 = 19;
+
+fn main(){
+    std::println!("{}", baz!());
+}
diff --git a/src/test/ui/proc-macro/expand-with-a-macro.rs b/src/test/ui/proc-macro/expand-with-a-macro.rs
index 21a4547d11e1..042a28365951 100644
--- a/src/test/ui/proc-macro/expand-with-a-macro.rs
+++ b/src/test/ui/proc-macro/expand-with-a-macro.rs
@@ -2,7 +2,6 @@
 // needs-unwind
 // aux-build:expand-with-a-macro.rs
 
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![deny(warnings)]
 
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-1.rs b/src/test/ui/proc-macro/invalid-punct-ident-1.rs
index 814cd77cfe9b..9a1802737722 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-1.rs
+++ b/src/test/ui/proc-macro/invalid-punct-ident-1.rs
@@ -1,4 +1,5 @@
 // aux-build:invalid-punct-ident.rs
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate invalid_punct_ident;
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-1.stderr b/src/test/ui/proc-macro/invalid-punct-ident-1.stderr
index 7babe685bedf..78aa84401a50 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-1.stderr
+++ b/src/test/ui/proc-macro/invalid-punct-ident-1.stderr
@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-1.rs:6:1
+  --> $DIR/invalid-punct-ident-1.rs:7:1
    |
 LL | invalid_punct!();
    | ^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-2.rs b/src/test/ui/proc-macro/invalid-punct-ident-2.rs
index a04dec707fe4..afb6985e4582 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-2.rs
+++ b/src/test/ui/proc-macro/invalid-punct-ident-2.rs
@@ -1,4 +1,5 @@
 // aux-build:invalid-punct-ident.rs
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate invalid_punct_ident;
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-2.stderr b/src/test/ui/proc-macro/invalid-punct-ident-2.stderr
index 01b80768c574..66979e756aec 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-2.stderr
+++ b/src/test/ui/proc-macro/invalid-punct-ident-2.stderr
@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-2.rs:6:1
+  --> $DIR/invalid-punct-ident-2.rs:7:1
    |
 LL | invalid_ident!();
    | ^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-3.rs b/src/test/ui/proc-macro/invalid-punct-ident-3.rs
index f0e953608cb5..ff83695c5624 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-3.rs
+++ b/src/test/ui/proc-macro/invalid-punct-ident-3.rs
@@ -1,4 +1,5 @@
 // aux-build:invalid-punct-ident.rs
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate invalid_punct_ident;
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-3.stderr b/src/test/ui/proc-macro/invalid-punct-ident-3.stderr
index 899c38158c2d..c096bc8c0439 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-3.stderr
+++ b/src/test/ui/proc-macro/invalid-punct-ident-3.stderr
@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-3.rs:6:1
+  --> $DIR/invalid-punct-ident-3.rs:7:1
    |
 LL | invalid_raw_ident!();
    | ^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-4.rs b/src/test/ui/proc-macro/invalid-punct-ident-4.rs
index 59b347dac679..2d2774bd194c 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-4.rs
+++ b/src/test/ui/proc-macro/invalid-punct-ident-4.rs
@@ -1,4 +1,5 @@
 // aux-build:invalid-punct-ident.rs
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate invalid_punct_ident;
diff --git a/src/test/ui/proc-macro/invalid-punct-ident-4.stderr b/src/test/ui/proc-macro/invalid-punct-ident-4.stderr
index deb93b893685..ab4116141d81 100644
--- a/src/test/ui/proc-macro/invalid-punct-ident-4.stderr
+++ b/src/test/ui/proc-macro/invalid-punct-ident-4.stderr
@@ -1,5 +1,5 @@
 error: unexpected closing delimiter: `)`
-  --> $DIR/invalid-punct-ident-4.rs:6:1
+  --> $DIR/invalid-punct-ident-4.rs:7:1
    |
 LL | lexer_failure!();
    | ^^^^^^^^^^^^^^^^ unexpected closing delimiter
@@ -7,13 +7,13 @@ LL | lexer_failure!();
    = note: this error originates in the macro `lexer_failure` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-4.rs:6:1
+  --> $DIR/invalid-punct-ident-4.rs:7:1
    |
 LL | lexer_failure!();
    | ^^^^^^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/invalid-punct-ident-4.rs:11:33
+  --> $DIR/invalid-punct-ident-4.rs:12:33
    |
 LL |     let _recovery_witness: () = 0;
    |                            --   ^ expected `()`, found integer
diff --git a/src/test/ui/proc-macro/issue-36935.rs b/src/test/ui/proc-macro/issue-36935.rs
index 5c43a564c00c..03cdfa05e6b2 100644
--- a/src/test/ui/proc-macro/issue-36935.rs
+++ b/src/test/ui/proc-macro/issue-36935.rs
@@ -1,4 +1,5 @@
 // aux-build:test-macros.rs
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate test_macros;
diff --git a/src/test/ui/proc-macro/issue-36935.stderr b/src/test/ui/proc-macro/issue-36935.stderr
index 079e134c6f84..12290379853f 100644
--- a/src/test/ui/proc-macro/issue-36935.stderr
+++ b/src/test/ui/proc-macro/issue-36935.stderr
@@ -1,5 +1,5 @@
 error[E0428]: the name `Baz` is defined multiple times
-  --> $DIR/issue-36935.rs:7:1
+  --> $DIR/issue-36935.rs:8:1
    |
 LL | struct Baz {
    | ^^^^^^^^^^
@@ -10,7 +10,7 @@ LL | struct Baz {
    = note: `Baz` must be defined only once in the type namespace of this module
 
 error: proc-macro derive panicked
-  --> $DIR/issue-36935.rs:6:20
+  --> $DIR/issue-36935.rs:7:20
    |
 LL | #[derive(Identity, Panic)]
    |                    ^^^^^
diff --git a/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.rs b/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.rs
index 98fa06b6e457..5aefec3ece03 100644
--- a/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.rs
+++ b/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.rs
@@ -1,5 +1,6 @@
 // aux-build:proc-macro-panic.rs
 // edition:2018
+// needs-unwind proc macro panics to report errors
 
 // Regression test for issue #76270
 // Tests that we don't print an ICE message when a panic
diff --git a/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.stderr b/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.stderr
index 1dc0f16bf6c4..d69de23a4c0a 100644
--- a/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.stderr
+++ b/src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.stderr
@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/issue-76270-panic-in-libproc-macro.rs:10:1
+  --> $DIR/issue-76270-panic-in-libproc-macro.rs:11:1
    |
 LL | proc_macro_panic::panic_in_libproc_macro!();
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/proc-macro/load-panic-backtrace.rs b/src/test/ui/proc-macro/load-panic-backtrace.rs
index cd6f70a55758..bcdcb704a753 100644
--- a/src/test/ui/proc-macro/load-panic-backtrace.rs
+++ b/src/test/ui/proc-macro/load-panic-backtrace.rs
@@ -3,6 +3,7 @@
 // rustc-env:RUST_BACKTRACE=0
 // normalize-stderr-test "thread '.*' panicked " -> ""
 // normalize-stderr-test "note:.*RUST_BACKTRACE=1.*\n" -> ""
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate test_macros;
diff --git a/src/test/ui/proc-macro/load-panic-backtrace.stderr b/src/test/ui/proc-macro/load-panic-backtrace.stderr
index cef5786d1b8a..45d4fd1c9bc4 100644
--- a/src/test/ui/proc-macro/load-panic-backtrace.stderr
+++ b/src/test/ui/proc-macro/load-panic-backtrace.stderr
@@ -1,6 +1,6 @@
 at 'panic-derive', $DIR/auxiliary/test-macros.rs:43:5
 error: proc-macro derive panicked
-  --> $DIR/load-panic-backtrace.rs:10:10
+  --> $DIR/load-panic-backtrace.rs:11:10
    |
 LL | #[derive(Panic)]
    |          ^^^^^
diff --git a/src/test/ui/proc-macro/load-panic.rs b/src/test/ui/proc-macro/load-panic.rs
index 2e9a311d882b..6ce88c400e0f 100644
--- a/src/test/ui/proc-macro/load-panic.rs
+++ b/src/test/ui/proc-macro/load-panic.rs
@@ -1,4 +1,5 @@
 // aux-build:test-macros.rs
+// needs-unwind proc macro panics to report errors
 
 #[macro_use]
 extern crate test_macros;
diff --git a/src/test/ui/proc-macro/load-panic.stderr b/src/test/ui/proc-macro/load-panic.stderr
index 40cc4ee0e3d3..f0d62f690fd3 100644
--- a/src/test/ui/proc-macro/load-panic.stderr
+++ b/src/test/ui/proc-macro/load-panic.stderr
@@ -1,5 +1,5 @@
 error: proc-macro derive panicked
-  --> $DIR/load-panic.rs:6:10
+  --> $DIR/load-panic.rs:7:10
    |
 LL | #[derive(Panic)]
    |          ^^^^^
diff --git a/src/test/ui/proc-macro/signature.stderr b/src/test/ui/proc-macro/signature.stderr
index 78b0beff0da3..59b3e44c74a5 100644
--- a/src/test/ui/proc-macro/signature.stderr
+++ b/src/test/ui/proc-macro/signature.stderr
@@ -10,7 +10,7 @@ LL | | }
    | |_call the function in a closure: `|| unsafe { /* code */ }`
    |   required by a bound introduced by this call
    |
-   = help: the trait `Fn<(proc_macro::TokenStream,)>` is not implemented for `unsafe extern "C" fn(i32, u32) -> u32 {foo}`
+   = help: the trait `Fn<(proc_macro::TokenStream,)>` is not implemented for fn item `unsafe extern "C" fn(i32, u32) -> u32 {foo}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `ProcMacro::custom_derive`
   --> $SRC_DIR/proc_macro/src/bridge/client.rs:LL:COL
diff --git a/src/test/ui/process/core-run-destroy.rs b/src/test/ui/process/core-run-destroy.rs
index 5fd418e6c86c..d0e97bf01f38 100644
--- a/src/test/ui/process/core-run-destroy.rs
+++ b/src/test/ui/process/core-run-destroy.rs
@@ -8,6 +8,7 @@
 // ignore-emscripten no processes
 // ignore-sgx no processes
 // ignore-vxworks no 'cat' and 'sleep'
+// ignore-fuchsia no 'cat'
 
 // N.B., these tests kill child processes. Valgrind sees these children as leaking
 // memory, which makes for some *confusing* logs. That's why these are here
diff --git a/src/test/ui/process/process-envs.rs b/src/test/ui/process/process-envs.rs
index 8fc99b23fd21..f3a469791427 100644
--- a/src/test/ui/process/process-envs.rs
+++ b/src/test/ui/process/process-envs.rs
@@ -2,6 +2,7 @@
 // ignore-emscripten no processes
 // ignore-sgx no processes
 // ignore-vxworks no 'env'
+// ignore-fuchsia no 'env'
 
 use std::process::Command;
 use std::env;
diff --git a/src/test/ui/process/process-remove-from-env.rs b/src/test/ui/process/process-remove-from-env.rs
index af4e49dfdbb5..ad027d68588f 100644
--- a/src/test/ui/process/process-remove-from-env.rs
+++ b/src/test/ui/process/process-remove-from-env.rs
@@ -2,6 +2,7 @@
 // ignore-emscripten no processes
 // ignore-sgx no processes
 // ignore-vxworks no 'env'
+// ignore-fuchsia no 'env'
 
 use std::process::Command;
 use std::env;
diff --git a/src/test/ui/process/process-sigpipe.rs b/src/test/ui/process/process-sigpipe.rs
index ecf5e93c99ee..107eba45dc2f 100644
--- a/src/test/ui/process/process-sigpipe.rs
+++ b/src/test/ui/process/process-sigpipe.rs
@@ -14,6 +14,7 @@
 
 // ignore-emscripten no threads support
 // ignore-vxworks no 'sh'
+// ignore-fuchsia no 'sh'
 
 use std::process;
 use std::thread;
diff --git a/src/test/ui/process/process-spawn-nonexistent.rs b/src/test/ui/process/process-spawn-nonexistent.rs
index a513722639ad..9dd608986df1 100644
--- a/src/test/ui/process/process-spawn-nonexistent.rs
+++ b/src/test/ui/process/process-spawn-nonexistent.rs
@@ -1,6 +1,7 @@
 // run-pass
 // ignore-emscripten no processes
 // ignore-sgx no processes
+// ignore-fuchsia ErrorKind not translated
 
 use std::io::ErrorKind;
 use std::process::Command;
diff --git a/src/test/ui/process/signal-exit-status.rs b/src/test/ui/process/signal-exit-status.rs
index 0963dcc80f6b..9519ed7b4c7b 100644
--- a/src/test/ui/process/signal-exit-status.rs
+++ b/src/test/ui/process/signal-exit-status.rs
@@ -2,6 +2,7 @@
 // ignore-emscripten no processes
 // ignore-sgx no processes
 // ignore-windows
+// ignore-fuchsia code returned as ZX_TASK_RETCODE_EXCEPTION_KILL, FIXME (#58590)
 
 use std::env;
 use std::process::Command;
diff --git a/src/test/ui/query-system/query_depth.rs b/src/test/ui/query-system/query_depth.rs
new file mode 100644
index 000000000000..e600c1c08e5c
--- /dev/null
+++ b/src/test/ui/query-system/query_depth.rs
@@ -0,0 +1,31 @@
+// build-fail
+
+#![recursion_limit = "64"]
+type Byte = Option<Option<Option<Option< Option<Option<Option<Option<
+    Option<Option<Option<Option< Option<Option<Option<Option<
+        Option<Option<Option<Option< Option<Option<Option<Option<
+            Option<Option<Option<Option< Option<Option<Option<Option<
+                Option<Option<Option<Option< Option<Option<Option<Option<
+                    Option<Option<Option<Option< Option<Option<Option<Option<
+                        Option<Option<Option<Option< Option<Option<Option<Option<
+                            Option<Option<Option<Option< Option<Option<Option<Option<
+                                Option<Option<Option<Option< Option<Option<Option<Option<
+                                    Option<Option<Option<Option< Option<Option<Option<Option<
+                                        Option<Option<Option<Option< Option<Option<Option<Option<
+                                            Box<String>
+                                        >>>> >>>>
+                                    >>>> >>>>
+                                >>>> >>>>
+                            >>>> >>>>
+                        >>>> >>>>
+                    >>>> >>>>
+                >>>> >>>>
+            >>>> >>>>
+        >>>> >>>>
+    >>>> >>>>
+>>>> >>>>;
+
+fn main() {
+//~^ ERROR: queries overflow the depth limit!
+    println!("{}", std::mem::size_of::<Byte>());
+}
diff --git a/src/test/ui/query-system/query_depth.stderr b/src/test/ui/query-system/query_depth.stderr
new file mode 100644
index 000000000000..43a18b4e0745
--- /dev/null
+++ b/src/test/ui/query-system/query_depth.stderr
@@ -0,0 +1,11 @@
+error: queries overflow the depth limit!
+  --> $DIR/query_depth.rs:28:1
+   |
+LL | fn main() {
+   | ^^^^^^^^^
+   |
+   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "128"]` attribute to your crate (`query_depth`)
+   = note: query depth increased by 66 when computing layout of `core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<core::option::Option<alloc::boxed::Box<alloc::string::String>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr b/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
index acbd0d05984f..f2307899d3c4 100644
--- a/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
+++ b/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
@@ -6,7 +6,7 @@ LL |     let Ok(x) = res;
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
-note: `Result<u32, &R>` defined here
+note: `Result<u32, &R<'_>>` defined here
   --> $SRC_DIR/core/src/result.rs:LL:COL
    |
 LL | pub enum Result<T, E> {
@@ -14,12 +14,12 @@ LL | pub enum Result<T, E> {
 ...
 LL |     Err(#[stable(feature = "rust1", since = "1.0.0")] E),
    |     ^^^ not covered
-   = note: the matched value is of type `Result<u32, &R>`
+   = note: the matched value is of type `Result<u32, &R<'_>>`
 help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let x = if let Ok(x) = res { x } else { todo!() };
    |     ++++++++++                 ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Ok(x) = res else { todo!() };
    |                     ++++++++++++++++
diff --git a/src/test/ui/regions/issue-101280.rs b/src/test/ui/regions/issue-101280.rs
new file mode 100644
index 000000000000..29f158366f02
--- /dev/null
+++ b/src/test/ui/regions/issue-101280.rs
@@ -0,0 +1,10 @@
+use std::cell::Cell;
+
+type Ty = for<'r> fn(Cell<(&'r i32, &'r i32)>);
+
+fn f<'r>(f: fn(Cell<(&'r i32, &i32)>)) -> Ty {
+    f
+    //~^ ERROR mismatched types
+}
+
+fn main() {}
diff --git a/src/test/ui/regions/issue-101280.stderr b/src/test/ui/regions/issue-101280.stderr
new file mode 100644
index 000000000000..320d008aeff2
--- /dev/null
+++ b/src/test/ui/regions/issue-101280.stderr
@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-101280.rs:6:5
+   |
+LL | fn f<'r>(f: fn(Cell<(&'r i32, &i32)>)) -> Ty {
+   |                                           -- expected `for<'r> fn(Cell<(&'r i32, &'r i32)>)` because of return type
+LL |     f
+   |     ^ one type is more general than the other
+   |
+   = note: expected fn pointer `for<'r> fn(Cell<(&'r i32, &'r i32)>)`
+              found fn pointer `for<'a> fn(Cell<(&'r i32, &'a i32)>)`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/regions/issue-56537-closure-uses-region-from-container.rs b/src/test/ui/regions/issue-56537-closure-uses-region-from-container.rs
index bdd1ae91f7d7..a8f7a41c4428 100644
--- a/src/test/ui/regions/issue-56537-closure-uses-region-from-container.rs
+++ b/src/test/ui/regions/issue-56537-closure-uses-region-from-container.rs
@@ -5,7 +5,7 @@
 // by the function.
 //
 // This works today, which precludes changing things so that closures
-// follow the same lifetime-elision rules used elsehwere. See
+// follow the same lifetime-elision rules used elsewhere. See
 // rust-lang/rust#56537
 
 // check-pass
diff --git a/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr b/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
index 48f2e1a2fa21..3b62c7b61c1b 100644
--- a/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
+++ b/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
@@ -4,8 +4,8 @@ error[E0308]: mismatched types
 LL |     let _: fn(&mut &isize, &mut &isize) = a;
    |                                           ^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'r, 's, 't0, 't1> fn(&'r mut &'s isize, &'t0 mut &'t1 isize)`
-                 found fn item `for<'r, 's> fn(&'r mut &isize, &'s mut &isize) {a::<'_, '_>}`
+   = note: expected fn pointer `for<'a, 'b, 'c, 'd> fn(&'a mut &'b isize, &'c mut &'d isize)`
+                 found fn item `for<'a, 'b> fn(&'a mut &isize, &'b mut &isize) {a::<'_, '_>}`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr b/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
index 36f40cd9a0f6..8a18a234b5c4 100644
--- a/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
+++ b/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
@@ -4,8 +4,8 @@ error[E0308]: mismatched types
 LL |     let _: fn(&mut &isize, &mut &isize, &mut &isize) = a;
    |                                                        ^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'r, 's, 't0, 't1, 't2, 't3> fn(&'r mut &'s isize, &'t0 mut &'t1 isize, &'t2 mut &'t3 isize)`
-                 found fn item `for<'r, 's, 't0> fn(&'r mut &isize, &'s mut &isize, &'t0 mut &isize) {a::<'_, '_, '_>}`
+   = note: expected fn pointer `for<'a, 'b, 'c, 'd, 'e, 'f> fn(&'a mut &'b isize, &'c mut &'d isize, &'e mut &'f isize)`
+                 found fn item `for<'a, 'b, 'c> fn(&'a mut &isize, &'b mut &isize, &'c mut &isize) {a::<'_, '_, '_>}`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/regions/regions-fn-subtyping-return-static-fail.stderr b/src/test/ui/regions/regions-fn-subtyping-return-static-fail.stderr
index d87d0d2f6f99..8d82ff958ff3 100644
--- a/src/test/ui/regions/regions-fn-subtyping-return-static-fail.stderr
+++ b/src/test/ui/regions/regions-fn-subtyping-return-static-fail.stderr
@@ -7,7 +7,7 @@ LL |     want_G(baz);
    |     arguments to this function are incorrect
    |
    = note: expected fn pointer `for<'cx> fn(&'cx S) -> &'static S`
-                 found fn item `for<'r> fn(&'r S) -> &'r S {baz}`
+                 found fn item `for<'a> fn(&'a S) -> &'a S {baz}`
 note: function defined here
   --> $DIR/regions-fn-subtyping-return-static-fail.rs:20:4
    |
diff --git a/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr b/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr
index a0daf58c6b57..17a9019436a1 100644
--- a/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr
+++ b/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr
@@ -4,8 +4,8 @@ error[E0308]: mismatched types
 LL |     let _: fn(&mut &isize, &mut &isize) = a;
    |                                           ^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'r, 's, 't0, 't1> fn(&'r mut &'s isize, &'t0 mut &'t1 isize)`
-                 found fn item `for<'r, 's> fn(&'r mut &isize, &'s mut &isize) {a::<'_, '_>}`
+   = note: expected fn pointer `for<'a, 'b, 'c, 'd> fn(&'a mut &'b isize, &'c mut &'d isize)`
+                 found fn item `for<'a, 'b> fn(&'a mut &isize, &'b mut &isize) {a::<'_, '_>}`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/repr/invalid_repr_list_help.rs b/src/test/ui/repr/invalid_repr_list_help.rs
new file mode 100644
index 000000000000..c320984536ca
--- /dev/null
+++ b/src/test/ui/repr/invalid_repr_list_help.rs
@@ -0,0 +1,17 @@
+#![crate_type = "lib"]
+
+#[repr(uwu)] //~ERROR: unrecognized representation hint
+pub struct OwO;
+
+#[repr(uwu = "a")] //~ERROR: unrecognized representation hint
+pub struct OwO2(i32);
+
+#[repr(uwu(4))] //~ERROR: unrecognized representation hint
+pub struct OwO3 {
+    x: i32,
+}
+
+#[repr(uwu, u8)] //~ERROR: unrecognized representation hint
+pub enum OwO4 {
+    UwU = 1,
+}
diff --git a/src/test/ui/repr/invalid_repr_list_help.stderr b/src/test/ui/repr/invalid_repr_list_help.stderr
new file mode 100644
index 000000000000..2acd56d9a323
--- /dev/null
+++ b/src/test/ui/repr/invalid_repr_list_help.stderr
@@ -0,0 +1,35 @@
+error[E0552]: unrecognized representation hint
+  --> $DIR/invalid_repr_list_help.rs:3:8
+   |
+LL | #[repr(uwu)]
+   |        ^^^
+   |
+   = help: valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
+
+error[E0552]: unrecognized representation hint
+  --> $DIR/invalid_repr_list_help.rs:6:8
+   |
+LL | #[repr(uwu = "a")]
+   |        ^^^^^^^^^
+   |
+   = help: valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
+
+error[E0552]: unrecognized representation hint
+  --> $DIR/invalid_repr_list_help.rs:9:8
+   |
+LL | #[repr(uwu(4))]
+   |        ^^^^^^
+   |
+   = help: valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
+
+error[E0552]: unrecognized representation hint
+  --> $DIR/invalid_repr_list_help.rs:14:8
+   |
+LL | #[repr(uwu, u8)]
+   |        ^^^
+   |
+   = help: valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0552`.
diff --git a/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs b/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
index aaf0f7eaef0d..49462f52fb4c 100644
--- a/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
+++ b/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
@@ -14,7 +14,6 @@ trait B {
 impl B for A {
     async fn associated(); //~ ERROR without body
     //~^ ERROR cannot be declared `async`
-    //~| ERROR has an incompatible type for trait
 }
 
 fn main() {}
diff --git a/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr b/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
index d3214458eac1..1354abb4f144 100644
--- a/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
+++ b/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
@@ -14,6 +14,14 @@ LL |     async fn inherent();
    |                        |
    |                        help: provide a definition for the function: `{ <body> }`
 
+error: associated function in `impl` without body
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
+   |
+LL |     async fn associated();
+   |     ^^^^^^^^^^^^^^^^^^^^^-
+   |                          |
+   |                          help: provide a definition for the function: `{ <body> }`
+
 error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:11:5
    |
@@ -24,14 +32,8 @@ LL |     async fn associated();
    |
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
-error: associated function in `impl` without body
-  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
-   |
-LL |     async fn associated();
-   |     ^^^^^^^^^^^^^^^^^^^^^-
-   |                          |
-   |                          help: provide a definition for the function: `{ <body> }`
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
 error[E0706]: functions in traits cannot be declared `async`
   --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
@@ -43,26 +45,9 @@ LL |     async fn associated();
    |
    = note: `async` trait functions are not currently supported
    = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
-error[E0053]: method `associated` has an incompatible type for trait
-  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:26
-   |
-LL |     async fn associated();
-   |                          ^
-   |                          |
-   |                          checked the `Output` of this `async fn`, found opaque type
-   |                          expected `()`, found opaque type
-   |
-   = note: while checking the return type of the `async fn`
-note: type in trait
-  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:11:26
-   |
-LL |     async fn associated();
-   |                          ^
-   = note: expected fn pointer `fn()`
-              found fn pointer `fn() -> impl Future<Output = ()>`
+error: aborting due to 5 previous errors
 
-error: aborting due to 6 previous errors
-
-Some errors have detailed explanations: E0053, E0706.
-For more information about an error, try `rustc --explain E0053`.
+For more information about this error, try `rustc --explain E0706`.
diff --git a/src/test/ui/resolve/issue-73427.rs b/src/test/ui/resolve/issue-73427.rs
index 3c62782a8979..5c2459a59036 100644
--- a/src/test/ui/resolve/issue-73427.rs
+++ b/src/test/ui/resolve/issue-73427.rs
@@ -22,6 +22,10 @@ enum D {
     Unit,
 }
 
+enum E {
+    TupleWithFields(()),
+}
+
 fn main() {
     // Only variants without fields are suggested (and others mentioned in a note) where an enum
     // is used rather than a variant.
@@ -34,6 +38,8 @@ fn main() {
     //~^ ERROR expected value, found enum `C`
     D.foo();
     //~^ ERROR expected value, found enum `D`
+    E.foo();
+    //~^ ERROR expected value, found enum `E`
 
     // Only tuple variants are suggested in calls or tuple struct pattern matching.
 
diff --git a/src/test/ui/resolve/issue-73427.stderr b/src/test/ui/resolve/issue-73427.stderr
index 59bb98a340a5..a2ca46f0ce96 100644
--- a/src/test/ui/resolve/issue-73427.stderr
+++ b/src/test/ui/resolve/issue-73427.stderr
@@ -1,5 +1,5 @@
 error[E0423]: expected value, found enum `A`
-  --> $DIR/issue-73427.rs:29:5
+  --> $DIR/issue-73427.rs:33:5
    |
 LL |     A.foo();
    |     ^
@@ -23,7 +23,7 @@ LL |     (A::Tuple()).foo();
    |     ~~~~~~~~~~~~
 LL |     A::Unit.foo();
    |     ~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |     (A::StructWithFields { /* fields */ }).foo();
    |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -31,7 +31,7 @@ LL |     (A::TupleWithFields(/* fields */)).foo();
    |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0423]: expected value, found enum `B`
-  --> $DIR/issue-73427.rs:31:5
+  --> $DIR/issue-73427.rs:35:5
    |
 LL |     B.foo();
    |     ^
@@ -52,7 +52,7 @@ LL |     (B::TupleWithFields(/* fields */)).foo();
    |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0423]: expected value, found enum `C`
-  --> $DIR/issue-73427.rs:33:5
+  --> $DIR/issue-73427.rs:37:5
    |
 LL |     C.foo();
    |     ^
@@ -70,7 +70,7 @@ help: you might have meant to use the following enum variant
    |
 LL |     C::Unit.foo();
    |     ~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |     (C::StructWithFields { /* fields */ }).foo();
    |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -78,7 +78,7 @@ LL |     (C::TupleWithFields(/* fields */)).foo();
    |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0423]: expected value, found enum `D`
-  --> $DIR/issue-73427.rs:35:5
+  --> $DIR/issue-73427.rs:39:5
    |
 LL |     D.foo();
    |     ^
@@ -95,13 +95,37 @@ help: you might have meant to use the following enum variant
    |
 LL |     D::Unit.foo();
    |     ~~~~~~~
-help: the following enum variant is available
+help: alternatively, the following enum variant is available
    |
 LL |     (D::TupleWithFields(/* fields */)).foo();
    |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+error[E0423]: expected value, found enum `E`
+  --> $DIR/issue-73427.rs:41:5
+   |
+LL |     E.foo();
+   |     ^
+   |
+note: the enum is defined here
+  --> $DIR/issue-73427.rs:25:1
+   |
+LL | / enum E {
+LL | |     TupleWithFields(()),
+LL | | }
+   | |_^
+help: the following enum variant is available
+   |
+LL |     (E::TupleWithFields(/* fields */)).foo();
+   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+help: consider importing one of these items instead
+   |
+LL | use std::f32::consts::E;
+   |
+LL | use std::f64::consts::E;
+   |
+
 error[E0423]: expected function, tuple struct or tuple variant, found enum `A`
-  --> $DIR/issue-73427.rs:40:13
+  --> $DIR/issue-73427.rs:46:13
    |
 LL |     let x = A(3);
    |             ^
@@ -126,7 +150,7 @@ LL |     let x = A::TupleWithFields(3);
    |             ~~~~~~~~~~~~~~~~~~
 
 error[E0532]: expected tuple struct or tuple variant, found enum `A`
-  --> $DIR/issue-73427.rs:42:12
+  --> $DIR/issue-73427.rs:48:12
    |
 LL |     if let A(3) = x { }
    |            ^
@@ -150,7 +174,7 @@ LL |     if let A::Tuple(3) = x { }
 LL |     if let A::TupleWithFields(3) = x { }
    |            ~~~~~~~~~~~~~~~~~~
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
 Some errors have detailed explanations: E0423, E0532.
 For more information about an error, try `rustc --explain E0423`.
diff --git a/src/test/ui/resolve/name-collision-in-trait-fn-sig.rs b/src/test/ui/resolve/name-collision-in-trait-fn-sig.rs
new file mode 100644
index 000000000000..fba4ffa1c6ed
--- /dev/null
+++ b/src/test/ui/resolve/name-collision-in-trait-fn-sig.rs
@@ -0,0 +1,11 @@
+// check-pass
+// This is currently stable behavior, which was almost accidentally made an
+// error in #102161 since there is no test exercising it. I am not sure if
+// this _should_ be the desired behavior, but at least we should know if it
+// changes.
+
+fn main() {}
+
+trait Foo {
+    fn fn_with_type_named_same_as_local_in_param(b: i32, b: i32);
+}
diff --git a/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr b/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr
index d9c404e94acb..af9f4612ab34 100644
--- a/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr
+++ b/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr
@@ -2,7 +2,7 @@ error[E0574]: expected struct, variant or union type, found type parameter `Baz`
   --> $DIR/point-at-type-parameter-shadowing-another-type.rs:16:13
    |
 LL | impl<Baz> Foo<Baz> for Bar {
-   |      --- found this type pararmeter
+   |      --- found this type parameter
 ...
 LL |             Baz { num } => num,
    |             ^^^ not a struct, variant or union type
diff --git a/src/test/ui/resolve/privacy-enum-ctor.stderr b/src/test/ui/resolve/privacy-enum-ctor.stderr
index 7cf32775a33e..a369dc6db528 100644
--- a/src/test/ui/resolve/privacy-enum-ctor.stderr
+++ b/src/test/ui/resolve/privacy-enum-ctor.stderr
@@ -19,7 +19,7 @@ help: you might have meant to use the following enum variant
    |
 LL |         m::Z::Unit;
    |         ~~~~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |         (m::Z::Fn(/* fields */));
    |         ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -47,7 +47,7 @@ help: you might have meant to use the following enum variant
    |
 LL |         m::Z::Unit;
    |         ~~~~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |         (m::Z::Fn(/* fields */));
    |         ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -89,7 +89,7 @@ help: you might have meant to use the following enum variant
    |
 LL |     let _: E = E::Unit;
    |                ~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |     let _: E = (E::Fn(/* fields */));
    |                ~~~~~~~~~~~~~~~~~~~~~
@@ -143,7 +143,7 @@ help: you might have meant to use the following enum variant
    |
 LL |     let _: E = E::Unit;
    |                ~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |     let _: E = (E::Fn(/* fields */));
    |                ~~~~~~~~~~~~~~~~~~~~~
@@ -203,7 +203,7 @@ help: you might have meant to use the following enum variant
    |
 LL |     let _: Z = m::Z::Unit;
    |                ~~~~~~~~~~
-help: the following enum variants are available
+help: alternatively, the following enum variants are also available
    |
 LL |     let _: Z = (m::Z::Fn(/* fields */));
    |                ~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/src/test/ui/resolve/resolve-primitive-fallback.stderr b/src/test/ui/resolve/resolve-primitive-fallback.stderr
index f0eb1a4f4873..6d5d5bad9fe1 100644
--- a/src/test/ui/resolve/resolve-primitive-fallback.stderr
+++ b/src/test/ui/resolve/resolve-primitive-fallback.stderr
@@ -34,7 +34,7 @@ LL | pub const fn size_of<T>() -> usize {
 help: remove the extra argument
    |
 LL |     std::mem::size_of();
-   |     ~~~~~~~~~~~~~~~~~~~
+   |                      ~~
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs b/src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs
index cd57d9bca942..43888cecedab 100644
--- a/src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs
+++ b/src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs
@@ -2,7 +2,6 @@
 // run-pass
 // needs-unwind
 
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(test)]
 
diff --git a/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.rs b/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.rs
index 70253a4fc901..69a283c31633 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.rs
+++ b/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.rs
@@ -31,7 +31,7 @@ fn empty_non_exhaustive(x: EmptyNonExhaustiveEnum) {
 
 fn main() {
     match NonExhaustiveEnum::Unit {}
-    //~^ ERROR `Unit`, `Tuple(_)` and `Struct { .. }` not covered [E0004]
+    //~^ ERROR `NonExhaustiveEnum::Unit`, `NonExhaustiveEnum::Tuple(_)` and `NonExhaustiveEnum::Struct { .. }` not covered [E0004]
     match NormalEnum::Unit {}
-    //~^ ERROR `Unit`, `Tuple(_)` and `Struct { .. }` not covered [E0004]
+    //~^ ERROR `NormalEnum::Unit`, `NormalEnum::Tuple(_)` and `NormalEnum::Struct { .. }` not covered [E0004]
 }
diff --git a/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.stderr b/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.stderr
index 1f20904483fe..de1bf8be8854 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/enum_same_crate_empty_match.stderr
@@ -10,11 +10,11 @@ note: the lint level is defined here
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error[E0004]: non-exhaustive patterns: `Unit`, `Tuple(_)` and `Struct { .. }` not covered
+error[E0004]: non-exhaustive patterns: `NonExhaustiveEnum::Unit`, `NonExhaustiveEnum::Tuple(_)` and `NonExhaustiveEnum::Struct { .. }` not covered
   --> $DIR/enum_same_crate_empty_match.rs:33:11
    |
 LL |     match NonExhaustiveEnum::Unit {}
-   |           ^^^^^^^^^^^^^^^^^^^^^^^ patterns `Unit`, `Tuple(_)` and `Struct { .. }` not covered
+   |           ^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonExhaustiveEnum::Unit`, `NonExhaustiveEnum::Tuple(_)` and `NonExhaustiveEnum::Struct { .. }` not covered
    |
 note: `NonExhaustiveEnum` defined here
   --> $DIR/enum_same_crate_empty_match.rs:5:5
@@ -33,15 +33,15 @@ LL |     Struct { field: u32 }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~     match NonExhaustiveEnum::Unit {
-LL +         Unit | Tuple(_) | Struct { .. } => todo!(),
+LL +         NonExhaustiveEnum::Unit | NonExhaustiveEnum::Tuple(_) | NonExhaustiveEnum::Struct { .. } => todo!(),
 LL +     }
    |
 
-error[E0004]: non-exhaustive patterns: `Unit`, `Tuple(_)` and `Struct { .. }` not covered
+error[E0004]: non-exhaustive patterns: `NormalEnum::Unit`, `NormalEnum::Tuple(_)` and `NormalEnum::Struct { .. }` not covered
   --> $DIR/enum_same_crate_empty_match.rs:35:11
    |
 LL |     match NormalEnum::Unit {}
-   |           ^^^^^^^^^^^^^^^^ patterns `Unit`, `Tuple(_)` and `Struct { .. }` not covered
+   |           ^^^^^^^^^^^^^^^^ patterns `NormalEnum::Unit`, `NormalEnum::Tuple(_)` and `NormalEnum::Struct { .. }` not covered
    |
 note: `NormalEnum` defined here
   --> $DIR/enum_same_crate_empty_match.rs:14:5
@@ -60,7 +60,7 @@ LL |     Struct { field: u32 }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~     match NormalEnum::Unit {
-LL +         Unit | Tuple(_) | Struct { .. } => todo!(),
+LL +         NormalEnum::Unit | NormalEnum::Tuple(_) | NormalEnum::Struct { .. } => todo!(),
 LL +     }
    |
 
diff --git a/src/test/ui/rfc-2008-non-exhaustive/omitted-patterns.stderr b/src/test/ui/rfc-2008-non-exhaustive/omitted-patterns.stderr
index a9885449f3f0..4b9f8564d237 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/omitted-patterns.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/omitted-patterns.stderr
@@ -81,7 +81,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:58:9
    |
 LL |         _ => {}
-   |         ^ pattern `Struct { .. }` not covered
+   |         ^ pattern `NonExhaustiveEnum::Struct { .. }` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:57:16
@@ -95,7 +95,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:65:9
    |
 LL |         _ => {}
-   |         ^ pattern `Tuple(_)` not covered
+   |         ^ pattern `NonExhaustiveEnum::Tuple(_)` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:64:16
@@ -109,7 +109,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:75:9
    |
 LL |         _ => {}
-   |         ^ pattern `Unit` not covered
+   |         ^ pattern `NonExhaustiveEnum::Unit` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:74:16
@@ -123,7 +123,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:92:32
    |
 LL |         NestedNonExhaustive::A(_) => {}
-   |                                ^ patterns `Tuple(_)` and `Struct { .. }` not covered
+   |                                ^ patterns `NonExhaustiveEnum::Tuple(_)` and `NonExhaustiveEnum::Struct { .. }` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:89:12
@@ -137,7 +137,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:94:9
    |
 LL |         _ => {}
-   |         ^ pattern `C` not covered
+   |         ^ pattern `NestedNonExhaustive::C` not covered
    |
    = help: ensure that all variants are matched explicitly by adding the suggested match arms
    = note: the matched value is of type `NestedNonExhaustive` and the `non_exhaustive_omitted_patterns` attribute was found
@@ -146,7 +146,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:132:9
    |
 LL |         _ => {}
-   |         ^ pattern `A(_)` not covered
+   |         ^ pattern `NonExhaustiveSingleVariant::A(_)` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:130:12
@@ -160,7 +160,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:144:9
    |
 LL |         _ => {}
-   |         ^ pattern `Unstable` not covered
+   |         ^ pattern `UnstableEnum::Unstable` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:143:16
@@ -174,7 +174,7 @@ error: some variants are not matched explicitly
   --> $DIR/omitted-patterns.rs:168:9
    |
 LL |         _ => {}
-   |         ^ pattern `Unstable2` not covered
+   |         ^ pattern `OnlyUnstableEnum::Unstable2` not covered
    |
 note: the lint level is defined here
   --> $DIR/omitted-patterns.rs:165:12
diff --git a/src/test/ui/rfc-2008-non-exhaustive/stable-omitted-patterns.stderr b/src/test/ui/rfc-2008-non-exhaustive/stable-omitted-patterns.stderr
index 7cce178988aa..533e8abf2d68 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/stable-omitted-patterns.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/stable-omitted-patterns.stderr
@@ -16,7 +16,7 @@ error: some variants are not matched explicitly
   --> $DIR/stable-omitted-patterns.rs:23:9
    |
 LL |         _ => {}
-   |         ^ pattern `Stable2` not covered
+   |         ^ pattern `UnstableEnum::Stable2` not covered
    |
 note: the lint level is defined here
   --> $DIR/stable-omitted-patterns.rs:22:16
diff --git a/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match.stderr b/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match.stderr
index 32a5c07f1968..a9c54af0418a 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match.stderr
@@ -55,11 +55,11 @@ LL +         _ => todo!(),
 LL ~     }
    |
 
-error[E0004]: non-exhaustive patterns: `Tuple(_)` and `Struct { .. }` not covered
+error[E0004]: non-exhaustive patterns: `UninhabitedVariants::Tuple(_)` and `UninhabitedVariants::Struct { .. }` not covered
   --> $DIR/match.rs:31:11
    |
 LL |     match x {}
-   |           ^ patterns `Tuple(_)` and `Struct { .. }` not covered
+   |           ^ patterns `UninhabitedVariants::Tuple(_)` and `UninhabitedVariants::Struct { .. }` not covered
    |
 note: `UninhabitedVariants` defined here
   --> $DIR/auxiliary/uninhabited.rs:17:23
@@ -74,7 +74,7 @@ LL |     #[non_exhaustive] Struct { x: ! }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~     match x {
-LL +         Tuple(_) | Struct { .. } => todo!(),
+LL +         UninhabitedVariants::Tuple(_) | UninhabitedVariants::Struct { .. } => todo!(),
 LL ~     }
    |
 
diff --git a/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_same_crate.stderr b/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_same_crate.stderr
index c89c70ae6cc1..ec2a2f6f0553 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_same_crate.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_same_crate.stderr
@@ -36,11 +36,11 @@ LL +         _ => todo!(),
 LL ~     }
    |
 
-error[E0004]: non-exhaustive patterns: `Tuple(_)` and `Struct { .. }` not covered
+error[E0004]: non-exhaustive patterns: `UninhabitedVariants::Tuple(_)` and `UninhabitedVariants::Struct { .. }` not covered
   --> $DIR/match_same_crate.rs:38:11
    |
 LL |     match x {}
-   |           ^ patterns `Tuple(_)` and `Struct { .. }` not covered
+   |           ^ patterns `UninhabitedVariants::Tuple(_)` and `UninhabitedVariants::Struct { .. }` not covered
    |
 note: `UninhabitedVariants` defined here
   --> $DIR/match_same_crate.rs:16:23
@@ -55,7 +55,7 @@ LL |     #[non_exhaustive] Struct { x: ! }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~     match x {
-LL +         Tuple(_) | Struct { .. } => todo!(),
+LL +         UninhabitedVariants::Tuple(_) | UninhabitedVariants::Struct { .. } => todo!(),
 LL ~     }
    |
 
diff --git a/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_with_exhaustive_patterns.stderr b/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_with_exhaustive_patterns.stderr
index d854ea28ff68..b6b777ec56c4 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_with_exhaustive_patterns.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/uninhabited/match_with_exhaustive_patterns.stderr
@@ -55,11 +55,11 @@ LL +         _ => todo!(),
 LL ~     }
    |
 
-error[E0004]: non-exhaustive patterns: `Tuple(_)` and `Struct { .. }` not covered
+error[E0004]: non-exhaustive patterns: `UninhabitedVariants::Tuple(_)` and `UninhabitedVariants::Struct { .. }` not covered
   --> $DIR/match_with_exhaustive_patterns.rs:34:11
    |
 LL |     match x {}
-   |           ^ patterns `Tuple(_)` and `Struct { .. }` not covered
+   |           ^ patterns `UninhabitedVariants::Tuple(_)` and `UninhabitedVariants::Struct { .. }` not covered
    |
 note: `UninhabitedVariants` defined here
   --> $DIR/auxiliary/uninhabited.rs:17:23
@@ -74,7 +74,7 @@ LL |     #[non_exhaustive] Struct { x: ! }
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
 LL ~     match x {
-LL +         Tuple(_) | Struct { .. } => todo!(),
+LL +         UninhabitedVariants::Tuple(_) | UninhabitedVariants::Struct { .. } => todo!(),
 LL ~     }
    |
 
diff --git a/src/test/ui/rfc-2091-track-caller/std-panic-locations.rs b/src/test/ui/rfc-2091-track-caller/std-panic-locations.rs
index b067994a5c6d..f11456250d87 100644
--- a/src/test/ui/rfc-2091-track-caller/std-panic-locations.rs
+++ b/src/test/ui/rfc-2091-track-caller/std-panic-locations.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // revisions: default mir-opt
 //[mir-opt] compile-flags: -Zmir-opt-level=4
 
diff --git a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
index fce0cdfe0d56..bc06fde49e99 100644
--- a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
+++ b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
@@ -1493,17 +1493,11 @@ LL |     if (let 0 = 0)? {}
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/disallowed-positions.rs:132:19
    |
-LL | / fn nested_within_if_expr() {
-LL | |     if &let 0 = 0 {}
-LL | |
-LL | |
-...  |
-LL | |     if (let 0 = 0)? {}
-   | |                   ^ cannot use the `?` operator in a function that returns `()`
-...  |
-LL | |
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn nested_within_if_expr() {
+   | -------------------------- this function should return `Result` or `Option` to accept `?`
+...
+LL |     if (let 0 = 0)? {}
+   |                   ^ cannot use the `?` operator in a function that returns `()`
    |
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
@@ -1693,17 +1687,11 @@ LL |     while (let 0 = 0)? {}
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/disallowed-positions.rs:224:22
    |
-LL | / fn nested_within_while_expr() {
-LL | |     while &let 0 = 0 {}
-LL | |
-LL | |
-...  |
-LL | |     while (let 0 = 0)? {}
-   | |                      ^ cannot use the `?` operator in a function that returns `()`
-...  |
-LL | |
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn nested_within_while_expr() {
+   | ----------------------------- this function should return `Result` or `Option` to accept `?`
+...
+LL |     while (let 0 = 0)? {}
+   |                      ^ cannot use the `?` operator in a function that returns `()`
    |
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
@@ -1881,17 +1869,11 @@ LL |     (let 0 = 0)?;
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/disallowed-positions.rs:325:16
    |
-LL | / fn outside_if_and_while_expr() {
-LL | |     &let 0 = 0;
-LL | |
-LL | |
-...  |
-LL | |     (let 0 = 0)?;
-   | |                ^ cannot use the `?` operator in a function that returns `()`
-...  |
-LL | |
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn outside_if_and_while_expr() {
+   | ------------------------------ this function should return `Result` or `Option` to accept `?`
+...
+LL |     (let 0 = 0)?;
+   |                ^ cannot use the `?` operator in a function that returns `()`
    |
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
diff --git a/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
index 12befc637c78..2a6c144350a7 100644
--- a/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
@@ -1,4 +1,4 @@
-#![feature(let_chains, let_else)]
+#![feature(let_chains)]
 
 fn main() {
     let opt = Some(1i32);
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.rs b/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.rs
index 9e739c02dc8e..22d57f8beddd 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.rs
@@ -1,7 +1,6 @@
 // only-windows
 // only-x86
 #![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
 
 #[link(name = "foo", kind = "raw-dylib", import_name_type = 6)]
 //~^ ERROR import name type must be of the form `import_name_type = "string"`
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.stderr b/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.stderr
index ee10b0114a47..0e95fec29d25 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-invalid-format.stderr
@@ -1,17 +1,8 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/import-name-type-invalid-format.rs:3:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: import name type must be of the form `import_name_type = "string"`
-  --> $DIR/import-name-type-invalid-format.rs:6:42
+  --> $DIR/import-name-type-invalid-format.rs:5:42
    |
 LL | #[link(name = "foo", kind = "raw-dylib", import_name_type = 6)]
    |                                          ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.rs b/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.rs
index c404dbae4686..7ccb0082fb97 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.rs
@@ -2,7 +2,6 @@
 // only-windows
 // only-x86
 #![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
 
 #[link(name = "foo", kind = "raw-dylib", import_name_type = "decorated", import_name_type = "decorated")]
 //~^ ERROR multiple `import_name_type` arguments in a single `#[link]` attribute
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.stderr b/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.stderr
index 936c8aa73596..7c0e0be911f7 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-multiple.stderr
@@ -1,17 +1,8 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/import-name-type-multiple.rs:4:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: multiple `import_name_type` arguments in a single `#[link]` attribute
-  --> $DIR/import-name-type-multiple.rs:7:74
+  --> $DIR/import-name-type-multiple.rs:6:74
    |
 LL | #[link(name = "foo", kind = "raw-dylib", import_name_type = "decorated", import_name_type = "decorated")]
    |                                                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.rs b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.rs
index 350b0294641a..f728a578d3b8 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.rs
@@ -1,7 +1,6 @@
 // only-windows
 // only-x86
 #![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
 
 #[link(name = "foo", kind = "raw-dylib", import_name_type = "unknown")]
 //~^ ERROR unknown import name type `unknown`, expected one of: decorated, noprefix, undecorated
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.stderr b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.stderr
index b6871a0d3170..2b299f2fea31 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unknown-value.stderr
@@ -1,17 +1,8 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/import-name-type-unknown-value.rs:3:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: unknown import name type `unknown`, expected one of: decorated, noprefix, undecorated
-  --> $DIR/import-name-type-unknown-value.rs:6:42
+  --> $DIR/import-name-type-unknown-value.rs:5:42
    |
 LL | #[link(name = "foo", kind = "raw-dylib", import_name_type = "unknown")]
    |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.rs b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.rs
index b467917bacc3..ae9207864a2a 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.rs
@@ -1,7 +1,6 @@
 // only-windows
 // only-x86
 #![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
 
 #[link(name = "foo", import_name_type = "decorated")]
 //~^ ERROR import name type can only be used with link kind `raw-dylib`
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.stderr b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.stderr
index c35333fb88df..5898cd875a1c 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-unsupported-link-kind.stderr
@@ -1,23 +1,14 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/import-name-type-unsupported-link-kind.rs:3:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: import name type can only be used with link kind `raw-dylib`
-  --> $DIR/import-name-type-unsupported-link-kind.rs:6:22
+  --> $DIR/import-name-type-unsupported-link-kind.rs:5:22
    |
 LL | #[link(name = "foo", import_name_type = "decorated")]
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: import name type can only be used with link kind `raw-dylib`
-  --> $DIR/import-name-type-unsupported-link-kind.rs:10:39
+  --> $DIR/import-name-type-unsupported-link-kind.rs:9:39
    |
 LL | #[link(name = "bar", kind = "static", import_name_type = "decorated")]
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.rs b/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.rs
index 4e6de7d6ac37..346ea18a8f8e 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.rs
@@ -1,7 +1,5 @@
 // only-windows
 // ignore-x86
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
 #[link(name = "foo", kind = "raw-dylib", import_name_type = "decorated")]
 //~^ ERROR import name type is only supported on x86
 extern "C" { }
diff --git a/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.stderr b/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.stderr
index d8a585145a73..b56449299b71 100644
--- a/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/import-name-type-x86-only.stderr
@@ -1,17 +1,8 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/import-name-type-x86-only.rs:3:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: import name type is only supported on x86
-  --> $DIR/import-name-type-x86-only.rs:5:42
+  --> $DIR/import-name-type-x86-only.rs:3:42
    |
 LL | #[link(name = "foo", kind = "raw-dylib", import_name_type = "decorated")]
    |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.rs
index 77f425c3e453..1a128c87a0c3 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name="foo")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.stderr
index dfe9d031c776..481a06d2797d 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-and-name.stderr
@@ -1,23 +1,14 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-and-name.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: cannot use `#[link_name]` with `#[link_ordinal]`
-  --> $DIR/link-ordinal-and-name.rs:7:5
+  --> $DIR/link-ordinal-and-name.rs:6:5
    |
 LL |     #[link_ordinal(42)]
    |     ^^^^^^^^^^^^^^^^^^^
 
 error: cannot use `#[link_name]` with `#[link_ordinal]`
-  --> $DIR/link-ordinal-and-name.rs:11:5
+  --> $DIR/link-ordinal-and-name.rs:10:5
    |
 LL |     #[link_ordinal(5)]
    |     ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.rs
index 4687fe47f906..7c8da050cf62 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "foo")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.stderr
index 1d0fad6cb49d..55cdcad75a4a 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-invalid-format.stderr
@@ -1,14 +1,5 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-invalid-format.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: illegal ordinal format in `link_ordinal`
-  --> $DIR/link-ordinal-invalid-format.rs:6:5
+  --> $DIR/link-ordinal-invalid-format.rs:5:5
    |
 LL |     #[link_ordinal("JustMonika")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -16,12 +7,12 @@ LL |     #[link_ordinal("JustMonika")]
    = note: an unsuffixed integer value, e.g., `1`, is expected
 
 error: illegal ordinal format in `link_ordinal`
-  --> $DIR/link-ordinal-invalid-format.rs:9:5
+  --> $DIR/link-ordinal-invalid-format.rs:8:5
    |
 LL |     #[link_ordinal("JustMonika")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: an unsuffixed integer value, e.g., `1`, is expected
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.rs
index becf2700aebc..9feed3941104 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "foo")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.stderr
index 5b0ec869d03b..853cdad8c1c5 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-missing-argument.stderr
@@ -1,14 +1,5 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-missing-argument.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: incorrect number of arguments to `#[link_ordinal]`
-  --> $DIR/link-ordinal-missing-argument.rs:6:5
+  --> $DIR/link-ordinal-missing-argument.rs:5:5
    |
 LL |     #[link_ordinal()]
    |     ^^^^^^^^^^^^^^^^^
@@ -16,12 +7,12 @@ LL |     #[link_ordinal()]
    = note: the attribute requires exactly one argument
 
 error: incorrect number of arguments to `#[link_ordinal]`
-  --> $DIR/link-ordinal-missing-argument.rs:9:5
+  --> $DIR/link-ordinal-missing-argument.rs:8:5
    |
 LL |     #[link_ordinal()]
    |     ^^^^^^^^^^^^^^^^^
    |
    = note: the attribute requires exactly one argument
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.rs
index 7b07d09e72a5..631c363d4ba1 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.rs
@@ -1,6 +1,5 @@
 // only-windows
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "foo", kind = "raw-dylib")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.stderr
index 92a39b3d1b09..c0453d2bf011 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-multiple.stderr
@@ -1,35 +1,26 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-multiple.rs:2:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: multiple `link_ordinal` attributes
+  --> $DIR/link-ordinal-multiple.rs:6:5
+   |
+LL |     #[link_ordinal(1)]
+   |     ^^^^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+note: attribute also specified here
   --> $DIR/link-ordinal-multiple.rs:7:5
    |
-LL |     #[link_ordinal(1)]
-   |     ^^^^^^^^^^^^^^^^^^ help: remove this attribute
-   |
-note: attribute also specified here
-  --> $DIR/link-ordinal-multiple.rs:8:5
-   |
 LL |     #[link_ordinal(2)]
    |     ^^^^^^^^^^^^^^^^^^
 
 error: multiple `link_ordinal` attributes
-  --> $DIR/link-ordinal-multiple.rs:10:5
+  --> $DIR/link-ordinal-multiple.rs:9:5
    |
 LL |     #[link_ordinal(1)]
    |     ^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/link-ordinal-multiple.rs:11:5
+  --> $DIR/link-ordinal-multiple.rs:10:5
    |
 LL |     #[link_ordinal(2)]
    |     ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs
index 5d273d52a928..54e614164b3a 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link_ordinal(123)]
 //~^ ERROR attribute should be applied to a foreign function or static
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.stderr
index 8fa2f16f44df..ec4104fbe500 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.stderr
@@ -1,29 +1,20 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-not-foreign-fn.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: attribute should be applied to a foreign function or static
-  --> $DIR/link-ordinal-not-foreign-fn.rs:4:1
+  --> $DIR/link-ordinal-not-foreign-fn.rs:3:1
    |
 LL | #[link_ordinal(123)]
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: attribute should be applied to a foreign function or static
-  --> $DIR/link-ordinal-not-foreign-fn.rs:8:1
+  --> $DIR/link-ordinal-not-foreign-fn.rs:7:1
    |
 LL | #[link_ordinal(123)]
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: attribute should be applied to a foreign function or static
-  --> $DIR/link-ordinal-not-foreign-fn.rs:12:1
+  --> $DIR/link-ordinal-not-foreign-fn.rs:11:1
    |
 LL | #[link_ordinal(42)]
    | ^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors; 1 warning emitted
+error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.rs
index 99d7d9d0b7ed..46731581ebcb 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "foo")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.stderr
index 36f278bd8564..fef6de6aedfe 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-large.stderr
@@ -1,14 +1,5 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-too-large.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: ordinal value in `link_ordinal` is too large: `72436`
-  --> $DIR/link-ordinal-too-large.rs:6:5
+  --> $DIR/link-ordinal-too-large.rs:5:5
    |
 LL |     #[link_ordinal(72436)]
    |     ^^^^^^^^^^^^^^^^^^^^^^
@@ -16,12 +7,12 @@ LL |     #[link_ordinal(72436)]
    = note: the value may not exceed `u16::MAX`
 
 error: ordinal value in `link_ordinal` is too large: `72436`
-  --> $DIR/link-ordinal-too-large.rs:9:5
+  --> $DIR/link-ordinal-too-large.rs:8:5
    |
 LL |     #[link_ordinal(72436)]
    |     ^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the value may not exceed `u16::MAX`
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.rs
index eca4186e593e..71e0ac9f3ee4 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "foo")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.stderr
index 745aab24dc76..7e0fcd845cbd 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-too-many-arguments.stderr
@@ -1,14 +1,5 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-too-many-arguments.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: incorrect number of arguments to `#[link_ordinal]`
-  --> $DIR/link-ordinal-too-many-arguments.rs:6:5
+  --> $DIR/link-ordinal-too-many-arguments.rs:5:5
    |
 LL |     #[link_ordinal(3, 4)]
    |     ^^^^^^^^^^^^^^^^^^^^^
@@ -16,12 +7,12 @@ LL |     #[link_ordinal(3, 4)]
    = note: the attribute requires exactly one argument
 
 error: incorrect number of arguments to `#[link_ordinal]`
-  --> $DIR/link-ordinal-too-many-arguments.rs:9:5
+  --> $DIR/link-ordinal-too-many-arguments.rs:8:5
    |
 LL |     #[link_ordinal(3, 4)]
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the attribute requires exactly one argument
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.rs b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.rs
index 99f317399d76..329c93fc1963 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.rs
@@ -1,5 +1,4 @@
-#![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 
 #[link(name = "foo")]
 extern "C" {
diff --git a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.stderr b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.stderr
index f1eeb22da59c..5fbffbda570a 100644
--- a/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/link-ordinal-unsupported-link-kind.stderr
@@ -1,23 +1,14 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/link-ordinal-unsupported-link-kind.rs:1:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: `#[link_ordinal]` is only supported if link kind is `raw-dylib`
-  --> $DIR/link-ordinal-unsupported-link-kind.rs:6:5
+  --> $DIR/link-ordinal-unsupported-link-kind.rs:5:5
    |
 LL |     #[link_ordinal(3)]
    |     ^^^^^^^^^^^^^^^^^^
 
 error: `#[link_ordinal]` is only supported if link kind is `raw-dylib`
-  --> $DIR/link-ordinal-unsupported-link-kind.rs:13:5
+  --> $DIR/link-ordinal-unsupported-link-kind.rs:12:5
    |
 LL |     #[link_ordinal(3)]
    |     ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.rs b/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.rs
index 13c9aa01e34a..6542faad2641 100644
--- a/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.rs
@@ -3,7 +3,6 @@
 // compile-flags: --crate-type lib --emit link
 #![allow(clashing_extern_declarations)]
 #![feature(raw_dylib)]
-//~^ WARN the feature `raw_dylib` is incomplete
 #[link(name = "foo", kind = "raw-dylib")]
 extern "C" {
     fn f(x: i32);
diff --git a/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.stderr b/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.stderr
index 93ca8f4d8d44..c6808bec7b5c 100644
--- a/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/multiple-declarations.stderr
@@ -1,17 +1,8 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/multiple-declarations.rs:5:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error: multiple declarations of external function `f` from library `foo.dll` have different calling conventions
-  --> $DIR/multiple-declarations.rs:15:9
+  --> $DIR/multiple-declarations.rs:14:9
    |
 LL |         fn f(x: i32);
    |         ^^^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.rs b/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.rs
index 5856b18aa160..4efffbd532e1 100644
--- a/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.rs
@@ -1,7 +1,6 @@
 // ignore-windows
 // compile-flags: --crate-type lib
-#![feature(raw_dylib)]
-//~^ WARNING: the feature `raw_dylib` is incomplete
+#![cfg_attr(target_arch = "x86", feature(raw_dylib))]
 #[link(name = "foo", kind = "raw-dylib")]
 //~^ ERROR: link kind `raw-dylib` is only supported on Windows targets
 extern "C" {}
diff --git a/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.stderr b/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.stderr
index 600aac81a359..14e791f1fb9a 100644
--- a/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/raw-dylib-windows-only.stderr
@@ -1,18 +1,9 @@
-warning: the feature `raw_dylib` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/raw-dylib-windows-only.rs:3:12
-   |
-LL | #![feature(raw_dylib)]
-   |            ^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #58713 <https://github.com/rust-lang/rust/issues/58713> for more information
-
 error[E0455]: link kind `raw-dylib` is only supported on Windows targets
-  --> $DIR/raw-dylib-windows-only.rs:5:29
+  --> $DIR/raw-dylib-windows-only.rs:4:29
    |
 LL | #[link(name = "foo", kind = "raw-dylib")]
    |                             ^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0455`.
diff --git a/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.rs b/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.rs
index dc647fd63f52..2f5a23e47a74 100644
--- a/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.rs
+++ b/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.rs
@@ -1,8 +1,6 @@
 // only-x86_64
 // only-windows
 // compile-flags: --crate-type lib --emit link
-#![allow(incomplete_features)]
-#![feature(raw_dylib)]
 #[link(name = "foo", kind = "raw-dylib")]
 extern "stdcall" {
     fn f(x: i32);
diff --git a/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.stderr b/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.stderr
index d8a2a6af9c19..f8265ae69194 100644
--- a/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.stderr
+++ b/src/test/ui/rfc-2627-raw-dylib/unsupported-abi.stderr
@@ -1,5 +1,5 @@
 error: ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture
-  --> $DIR/unsupported-abi.rs:8:5
+  --> $DIR/unsupported-abi.rs:6:5
    |
 LL |     fn f(x: i32);
    |     ^^^^^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.rs b/src/test/ui/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.rs
new file mode 100644
index 000000000000..780a510c500d
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.rs
@@ -0,0 +1,14 @@
+// check-pass
+#![feature(const_trait_impl)]
+
+#[const_trait]
+trait Foo {
+    type Assoc: ~const Foo;
+    fn foo() {}
+}
+
+const fn foo<T: ~const Foo>() {
+    <T as Foo>::Assoc::foo();
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
index 99eacaa837f9..7d9dae52cf10 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
@@ -10,6 +10,7 @@ impl std::ops::Add for NonConstAdd {
     }
 }
 
+#[const_trait]
 trait Foo {
     type Bar: ~const std::ops::Add;
 }
@@ -19,6 +20,7 @@ impl const Foo for NonConstAdd {
     //~^ ERROR: cannot add `NonConstAdd` to `NonConstAdd` in const contexts
 }
 
+#[const_trait]
 trait Baz {
     type Qux: std::ops::Add;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr
index 64501c523741..ce2425010ad2 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr
@@ -1,17 +1,17 @@
 error[E0277]: cannot add `NonConstAdd` to `NonConstAdd` in const contexts
-  --> $DIR/assoc-type.rs:18:16
+  --> $DIR/assoc-type.rs:19:16
    |
 LL |     type Bar = NonConstAdd;
    |                ^^^^^^^^^^^ no implementation for `NonConstAdd + NonConstAdd`
    |
    = help: the trait `~const Add` is not implemented for `NonConstAdd`
 note: the trait `Add` is implemented for `NonConstAdd`, but that implementation is not `const`
-  --> $DIR/assoc-type.rs:18:16
+  --> $DIR/assoc-type.rs:19:16
    |
 LL |     type Bar = NonConstAdd;
    |                ^^^^^^^^^^^
 note: required by a bound in `Foo::Bar`
-  --> $DIR/assoc-type.rs:14:15
+  --> $DIR/assoc-type.rs:15:15
    |
 LL |     type Bar: ~const std::ops::Add;
    |               ^^^^^^^^^^^^^^^^^^^^ required by this bound in `Foo::Bar`
diff --git a/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs b/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs
index 19e9006094be..589e3f02420f 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs
@@ -3,6 +3,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait MyTrait {
     #[stable(feature = "rust1", since = "1.0.0")]
     fn func();
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs
index 24b9235bb9a7..dd9933974207 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs
@@ -1,5 +1,6 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 pub trait Plus {
     fn plus(self, rhs: Self) -> Self;
 }
@@ -23,7 +24,6 @@ pub const fn add_i32(a: i32, b: i32) -> i32 {
 pub const fn add_u32(a: u32, b: u32) -> u32 {
     a.plus(b)
     //~^ ERROR the trait bound
-    //~| ERROR cannot call non-const fn
 }
 
 fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr
index 1fc9db277610..d9ad80431533 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr
@@ -1,24 +1,19 @@
 error[E0277]: the trait bound `u32: ~const Plus` is not satisfied
-  --> $DIR/call-const-trait-method-fail.rs:24:7
+  --> $DIR/call-const-trait-method-fail.rs:25:7
    |
 LL |     a.plus(b)
-   |       ^^^^^^^ the trait `~const Plus` is not implemented for `u32`
+   |       ^^^^ the trait `~const Plus` is not implemented for `u32`
    |
 note: the trait `Plus` is implemented for `u32`, but that implementation is not `const`
-  --> $DIR/call-const-trait-method-fail.rs:24:7
+  --> $DIR/call-const-trait-method-fail.rs:25:7
    |
 LL |     a.plus(b)
-   |       ^^^^^^^
-
-error[E0015]: cannot call non-const fn `<u32 as Plus>::plus` in constant functions
-  --> $DIR/call-const-trait-method-fail.rs:24:7
+   |       ^^^^
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
-LL |     a.plus(b)
-   |       ^^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+LL | pub const fn add_u32(a: u32, b: u32) -> u32 where u32: ~const Plus {
+   |                                             ++++++++++++++++++++++
 
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0015, E0277.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs
index cf38bc3c9645..b64161b6aa01 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs
@@ -21,6 +21,7 @@ impl const PartialEq for Int {
     }
 }
 
+#[const_trait]
 pub trait Plus {
     fn plus(self, rhs: Self) -> Self;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs b/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs
index 89dc47aad3dd..50c46579086c 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs
@@ -1,6 +1,7 @@
 // check-pass
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait MyPartialEq {
     fn eq(&self, other: &Self) -> bool;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs
index b3e3dd62be80..52984fb6be49 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs
@@ -1,6 +1,7 @@
 #![feature(const_trait_impl)]
 
 struct S;
+#[const_trait]
 trait T {
     fn foo();
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr
index 9e49785c589e..c8783de4c3ee 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr
@@ -1,5 +1,5 @@
 error[E0015]: cannot call non-const fn `non_const` in constant functions
-  --> $DIR/const-check-fns-in-const-impl.rs:11:16
+  --> $DIR/const-check-fns-in-const-impl.rs:12:16
    |
 LL |     fn foo() { non_const() }
    |                ^^^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs b/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs
index 04462c0a11b8..8b4c40658156 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs
@@ -48,6 +48,7 @@ mod t {
     pub struct HasConstDrop(pub ConstDrop);
     pub struct TrivialFields(pub u8, pub i8, pub usize, pub isize);
 
+    #[const_trait]
     pub trait SomeTrait {
         fn foo();
     }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs
index 470c653dd470..837124db04e2 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs
@@ -1,9 +1,11 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {}
 
 const impl Foo for i32 {} //~ ERROR: expected identifier, found keyword
 
+#[const_trait]
 trait Bar {}
 
 const impl<T: Foo> Bar for T {} //~ ERROR: expected identifier, found keyword
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr
index 709084c86e0a..7217fc855435 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr
@@ -1,5 +1,5 @@
 error: expected identifier, found keyword `impl`
-  --> $DIR/const-impl-recovery.rs:5:7
+  --> $DIR/const-impl-recovery.rs:6:7
    |
 LL | const impl Foo for i32 {}
    |       ^^^^ expected identifier, found keyword
@@ -11,7 +11,7 @@ LL + impl const Foo for i32 {}
    |
 
 error: expected identifier, found keyword `impl`
-  --> $DIR/const-impl-recovery.rs:9:7
+  --> $DIR/const-impl-recovery.rs:11:7
    |
 LL | const impl<T: Foo> Bar for T {}
    |       ^^^^ expected identifier, found keyword
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs
new file mode 100644
index 000000000000..1aff05627850
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs
@@ -0,0 +1,9 @@
+#![feature(const_trait_impl)]
+
+pub trait A {}
+//~^ NOTE: this trait must be annotated with `#[const_trait]`
+
+impl const A for () {}
+//~^ ERROR: const `impl`s must be for traits marked with `#[const_trait]`
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr
new file mode 100644
index 000000000000..6b465a9c62e2
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr
@@ -0,0 +1,14 @@
+error: const `impl`s must be for traits marked with `#[const_trait]`
+  --> $DIR/const-impl-requires-const-trait.rs:6:1
+   |
+LL | impl const A for () {}
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+note: this trait must be annotated with `#[const_trait]`
+  --> $DIR/const-impl-requires-const-trait.rs:3:1
+   |
+LL | pub trait A {}
+   | ^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr
index af4d3909e405..4c630d33c551 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr
@@ -1,5 +1,5 @@
 error: fatal error triggered by #[rustc_error]
-  --> $DIR/feature-gate.rs:13:1
+  --> $DIR/feature-gate.rs:14:1
    |
 LL | fn main() {}
    | ^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs
index 7bac72e1bb6f..0b409fbaac9e 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs
@@ -5,6 +5,7 @@
 #![feature(rustc_attrs)]
 
 struct S;
+#[const_trait] //[stock]~ ERROR `const_trait` is a temporary placeholder
 trait T {}
 impl const T for S {}
 //[stock]~^ ERROR const trait impls are experimental
diff --git a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr
index 91a8bb578a82..0e938c1c55d0 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr
@@ -1,5 +1,5 @@
 error[E0658]: const trait impls are experimental
-  --> $DIR/feature-gate.rs:9:6
+  --> $DIR/feature-gate.rs:10:6
    |
 LL | impl const T for S {}
    |      ^^^^^
@@ -7,6 +7,15 @@ LL | impl const T for S {}
    = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
    = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
 
-error: aborting due to previous error
+error[E0658]: `const_trait` is a temporary placeholder for marking a trait that is suitable for `const` `impls` and all default bodies as `const`, which may be removed or renamed in the future.
+  --> $DIR/feature-gate.rs:8:1
+   |
+LL | #[const_trait]
+   | ^^^^^^^^^^^^^^
+   |
+   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
+   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs
index 80a4442de2cb..337c733403b2 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 pub trait MyTrait {
     fn method(&self) -> Option<()>;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr
index 32df63e449d4..6d2be1daa372 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr
@@ -1,5 +1,5 @@
 error[E0658]: `?` is not allowed in a `const fn`
-  --> $DIR/hir-const-check.rs:11:9
+  --> $DIR/hir-const-check.rs:12:9
    |
 LL |         Some(())?;
    |         ^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs b/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs
index 2cef803a90e0..f8ac793e4c12 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs
@@ -3,7 +3,9 @@
 
 struct S;
 
+#[const_trait]
 trait A {}
+#[const_trait]
 trait B {}
 
 impl const A for S {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs
index 1004bb28c59e..9f3f38ad4bc6 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs
@@ -16,6 +16,7 @@ pub trait IndexMut where Self: Index {
 
 impl Index for () { type Output = (); }
 
+#[cfg(not(any(nn, yn)))]
 impl const IndexMut for <() as Index>::Output {
     const C: <Self as Index>::Output = ();
     type Assoc = <Self as Index>::Output;
@@ -24,6 +25,15 @@ impl const IndexMut for <() as Index>::Output {
     {}
 }
 
+#[cfg(any(nn, yn))]
+impl IndexMut for <() as Index>::Output {
+    const C: <Self as Index>::Output = ();
+    type Assoc = <Self as Index>::Output;
+    fn foo(&mut self, x: <Self as Index>::Output) -> <Self as Index>::Output
+        where <Self as Index>::Output:,
+    {}
+}
+
 const C: <() as Index>::Output = ();
 
 fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs
index 97c27ce1a1cf..4d3469653948 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs
@@ -4,7 +4,9 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 pub trait Super {}
+#[const_trait]
 pub trait Sub: Super {}
 
 impl<A> const Super for &A where A: ~const Super {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/nested-closure.rs b/src/test/ui/rfc-2632-const-trait-impl/nested-closure.rs
new file mode 100644
index 000000000000..a851136009c4
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/nested-closure.rs
@@ -0,0 +1,12 @@
+// check-pass
+
+#![feature(const_trait_impl, once_cell)]
+
+use std::sync::LazyLock;
+
+static EXTERN_FLAGS: LazyLock<String> = LazyLock::new(|| {
+    let x = || String::new();
+    x()
+});
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs b/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs
index defef9e04098..1a4509b18695 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Convert<T> {
     fn to(self) -> T;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.rs b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.rs
new file mode 100644
index 000000000000..633543700d2e
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.rs
@@ -0,0 +1,31 @@
+#![feature(const_trait_impl, min_specialization, rustc_attrs)]
+
+#[rustc_specialization_trait]
+#[const_trait]
+pub trait Sup {}
+
+impl const Sup for () {}
+
+#[const_trait]
+pub trait A {
+    fn a() -> u32;
+}
+
+impl<T: Default> A for T {
+    default fn a() -> u32 {
+        2
+    }
+}
+
+impl<T: Default + ~const Sup> const A for T {
+    fn a() -> u32 {
+        3
+    }
+}
+
+const fn generic<T: Default>() {
+    <T as A>::a();
+    //~^ ERROR: the trait bound `T: ~const Sup` is not satisfied
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.stderr b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.stderr
new file mode 100644
index 000000000000..c554671e18d8
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.stderr
@@ -0,0 +1,19 @@
+error[E0277]: the trait bound `T: ~const Sup` is not satisfied
+  --> $DIR/specializing-constness-2.rs:27:5
+   |
+LL |     <T as A>::a();
+   |     ^^^^^^^^^^^^^ the trait `~const Sup` is not implemented for `T`
+   |
+note: required for `T` to implement `~const A`
+  --> $DIR/specializing-constness-2.rs:20:37
+   |
+LL | impl<T: Default + ~const Sup> const A for T {
+   |                                     ^     ^
+help: consider further restricting this bound
+   |
+LL | const fn generic<T: Default + ~const Sup>() {
+   |                             ++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.rs b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.rs
new file mode 100644
index 000000000000..ff0cd489d474
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.rs
@@ -0,0 +1,26 @@
+#![feature(const_trait_impl, min_specialization, rustc_attrs)]
+
+#[rustc_specialization_trait]
+#[const_trait]
+pub trait Sup {}
+
+impl const Sup for () {}
+
+#[const_trait]
+pub trait A {
+    fn a() -> u32;
+}
+
+impl<T: ~const Default> const A for T {
+    default fn a() -> u32 {
+        2
+    }
+}
+
+impl<T: Default + Sup> A for T { //~ ERROR: cannot specialize
+    fn a() -> u32 {
+        3
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.stderr b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.stderr
new file mode 100644
index 000000000000..3296c109c4e7
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.stderr
@@ -0,0 +1,8 @@
+error: cannot specialize on trait `Default`
+  --> $DIR/specializing-constness.rs:20:9
+   |
+LL | impl<T: Default + Sup> A for T {
+   |         ^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/static-const-trait-bound.rs b/src/test/ui/rfc-2632-const-trait-impl/static-const-trait-bound.rs
new file mode 100644
index 000000000000..4520a36960c7
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/static-const-trait-bound.rs
@@ -0,0 +1,18 @@
+// check-pass
+pub struct S<T, F: FnOnce() -> T = fn() -> T> {
+    f: F,
+    x: Option<T>,
+}
+
+impl<T, F: FnOnce() -> T> S<T, F> {
+    pub const fn new(f: F) -> Self {
+        Self { f, x: None }
+    }
+}
+
+#[derive(Default)]
+pub struct Foo;
+
+static LOCKED_CALLSITES: S<Foo> = S::new(Default::default);
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs
index af465cad3d24..3e2b81368a5f 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs
@@ -1,8 +1,10 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {
     fn a(&self);
 }
+#[const_trait]
 trait Bar: ~const Foo {}
 
 struct S;
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr
index 9e8b8f8c6ba1..9787792ab131 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr
@@ -1,16 +1,16 @@
 error[E0277]: the trait bound `S: ~const Foo` is not satisfied
-  --> $DIR/super-traits-fail.rs:13:12
+  --> $DIR/super-traits-fail.rs:15:12
    |
 LL | impl const Bar for S {}
    |            ^^^ the trait `~const Foo` is not implemented for `S`
    |
 note: the trait `Foo` is implemented for `S`, but that implementation is not `const`
-  --> $DIR/super-traits-fail.rs:13:12
+  --> $DIR/super-traits-fail.rs:15:12
    |
 LL | impl const Bar for S {}
    |            ^^^
 note: required by a bound in `Bar`
-  --> $DIR/super-traits-fail.rs:6:12
+  --> $DIR/super-traits-fail.rs:8:12
    |
 LL | trait Bar: ~const Foo {}
    |            ^^^^^^^^^^ required by this bound in `Bar`
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs b/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs
index aded4ca9a998..df96f6fb4ab4 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs
@@ -1,9 +1,12 @@
 // check-pass
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {
     fn a(&self);
 }
+
+#[const_trait]
 trait Bar: ~const Foo {}
 
 struct S;
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.rs b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.rs
new file mode 100644
index 000000000000..b29b633cff64
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.rs
@@ -0,0 +1,34 @@
+// check-pass
+#![feature(const_trait_impl)]
+#![feature(generic_arg_infer)]
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+struct Foo<const N: usize>;
+
+impl<const N: usize> Foo<N> {
+   fn add<A: ~const Add42>(self) -> Foo<{ A::add(N) }> {
+      Foo
+   }
+}
+
+#[const_trait]
+trait Add42 {
+    fn add(a: usize) -> usize;
+}
+
+impl const Add42 for () {
+    fn add(a: usize) -> usize {
+        a + 42
+    }
+}
+
+fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
+    Foo
+}
+
+fn main() {
+   let foo = Foo::<0>;
+   let foo = bar::<(), _>(foo);
+   let _foo = bar::<(), _>(foo);
+}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
index b4302f3e75fd..350be4d8250d 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
@@ -17,12 +17,6 @@ fn rpit_assoc_bound() -> impl IntoIterator<Item: ~const T> { Some(S) }
 fn apit_assoc_bound(_: impl IntoIterator<Item: ~const T>) {}
 //~^ ERROR `~const` is not allowed
 
-fn generic<P: ~const T>() {}
-//~^ ERROR `~const` is not allowed
-
-fn where_clause<P>() where P: ~const T {}
-//~^ ERROR `~const` is not allowed
-
 struct TildeQuestion<T: ~const ?Sized>(std::marker::PhantomData<T>);
 //~^ ERROR `~const` and `?` are mutually exclusive
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
index 033ec21ba840..8d781d063d1c 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
@@ -4,7 +4,7 @@ error: `~const` is not allowed here
 LL | fn rpit() -> impl ~const T { S }
    |                   ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
 
 error: `~const` is not allowed here
   --> $DIR/tilde-const-invalid-places.rs:11:17
@@ -12,7 +12,7 @@ error: `~const` is not allowed here
 LL | fn apit(_: impl ~const T) {}
    |                 ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
 
 error: `~const` is not allowed here
   --> $DIR/tilde-const-invalid-places.rs:14:50
@@ -20,7 +20,7 @@ error: `~const` is not allowed here
 LL | fn rpit_assoc_bound() -> impl IntoIterator<Item: ~const T> { Some(S) }
    |                                                  ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
 
 error: `~const` is not allowed here
   --> $DIR/tilde-const-invalid-places.rs:17:48
@@ -28,29 +28,13 @@ error: `~const` is not allowed here
 LL | fn apit_assoc_bound(_: impl IntoIterator<Item: ~const T>) {}
    |                                                ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
-
-error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:20:15
-   |
-LL | fn generic<P: ~const T>() {}
-   |               ^^^^^^^^
-   |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
-
-error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:23:31
-   |
-LL | fn where_clause<P>() where P: ~const T {}
-   |                               ^^^^^^^^
-   |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
 
 error: `~const` and `?` are mutually exclusive
-  --> $DIR/tilde-const-invalid-places.rs:26:25
+  --> $DIR/tilde-const-invalid-places.rs:20:25
    |
 LL | struct TildeQuestion<T: ~const ?Sized>(std::marker::PhantomData<T>);
    |                         ^^^^^^^^^^^^^
 
-error: aborting due to 7 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs
new file mode 100644
index 000000000000..7a88ec35c8f2
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs
@@ -0,0 +1,29 @@
+// Like trait-where-clause.rs, but we are calling from a const context.
+// Checking the validity of traits' where clauses happen at a later stage.
+// (`rustc_const_eval` instead of `rustc_typeck`) Therefore one file as a
+// test is not enough.
+#![feature(const_trait_impl)]
+
+trait Bar {}
+
+trait Foo {
+    fn a();
+    fn b() where Self: ~const Bar;
+    fn c<T: ~const Bar>();
+}
+
+const fn test1<T: ~const Foo + Bar>() {
+    T::a();
+    T::b();
+    //~^ ERROR the trait bound
+    T::c::<T>();
+    //~^ ERROR the trait bound
+}
+
+const fn test2<T: ~const Foo + ~const Bar>() {
+    T::a();
+    T::b();
+    T::c::<T>();
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.stderr b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.stderr
new file mode 100644
index 000000000000..13d8639de30c
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.stderr
@@ -0,0 +1,35 @@
+error[E0277]: the trait bound `T: ~const Bar` is not satisfied
+  --> $DIR/trait-where-clause-const.rs:17:5
+   |
+LL |     T::b();
+   |     ^^^^^^ the trait `~const Bar` is not implemented for `T`
+   |
+note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
+  --> $DIR/trait-where-clause-const.rs:17:5
+   |
+LL |     T::b();
+   |     ^^^^^^
+help: consider further restricting this bound
+   |
+LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
+   |                                    ++++++++++++
+
+error[E0277]: the trait bound `T: ~const Bar` is not satisfied
+  --> $DIR/trait-where-clause-const.rs:19:5
+   |
+LL |     T::c::<T>();
+   |     ^^^^^^^^^^^ the trait `~const Bar` is not implemented for `T`
+   |
+note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
+  --> $DIR/trait-where-clause-const.rs:19:5
+   |
+LL |     T::c::<T>();
+   |     ^^^^^^^^^^^
+help: consider further restricting this bound
+   |
+LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
+   |                                    ++++++++++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs
index b7cf9a13b796..4b8b004069d4 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Bar {
     fn bar() -> u8;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs
index d37ed3bb8dd9..5bd23a8cb207 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs
@@ -8,7 +8,7 @@ trait Foo {
     fn c<T: ~const Bar>();
 }
 
-const fn test1<T: ~const Foo + Bar>() {
+fn test1<T: Foo>() {
     T::a();
     T::b();
     //~^ ERROR the trait bound
@@ -16,21 +16,7 @@ const fn test1<T: ~const Foo + Bar>() {
     //~^ ERROR the trait bound
 }
 
-const fn test2<T: ~const Foo + ~const Bar>() {
-    T::a();
-    T::b();
-    T::c::<T>();
-}
-
-fn test3<T: Foo>() {
-    T::a();
-    T::b();
-    //~^ ERROR the trait bound
-    T::c::<T>();
-    //~^ ERROR the trait bound
-}
-
-fn test4<T: Foo + Bar>() {
+fn test2<T: Foo + Bar>() {
     T::a();
     T::b();
     T::c::<T>();
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
index fd5fe25ddcfb..96365d334336 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
@@ -1,47 +1,5 @@
-error[E0277]: the trait bound `T: ~const Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:13:5
-   |
-LL |     T::b();
-   |     ^^^^ the trait `~const Bar` is not implemented for `T`
-   |
-note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
-  --> $DIR/trait-where-clause.rs:13:5
-   |
-LL |     T::b();
-   |     ^^^^
-note: required by a bound in `Foo::b`
-  --> $DIR/trait-where-clause.rs:7:24
-   |
-LL |     fn b() where Self: ~const Bar;
-   |                        ^^^^^^^^^^ required by this bound in `Foo::b`
-help: consider further restricting this bound
-   |
-LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
-   |                                    ++++++++++++
-
-error[E0277]: the trait bound `T: ~const Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:15:12
-   |
-LL |     T::c::<T>();
-   |            ^ the trait `~const Bar` is not implemented for `T`
-   |
-note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
-  --> $DIR/trait-where-clause.rs:15:12
-   |
-LL |     T::c::<T>();
-   |            ^
-note: required by a bound in `Foo::c`
-  --> $DIR/trait-where-clause.rs:8:13
-   |
-LL |     fn c<T: ~const Bar>();
-   |             ^^^^^^^^^^ required by this bound in `Foo::c`
-help: consider further restricting this bound
-   |
-LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
-   |                                    ++++++++++++
-
 error[E0277]: the trait bound `T: Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:27:5
+  --> $DIR/trait-where-clause.rs:13:5
    |
 LL |     T::b();
    |     ^^^^ the trait `Bar` is not implemented for `T`
@@ -53,11 +11,11 @@ LL |     fn b() where Self: ~const Bar;
    |                        ^^^^^^^^^^ required by this bound in `Foo::b`
 help: consider further restricting this bound
    |
-LL | fn test3<T: Foo + Bar>() {
+LL | fn test1<T: Foo + Bar>() {
    |                 +++++
 
 error[E0277]: the trait bound `T: Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:29:12
+  --> $DIR/trait-where-clause.rs:15:12
    |
 LL |     T::c::<T>();
    |            ^ the trait `Bar` is not implemented for `T`
@@ -69,9 +27,9 @@ LL |     fn c<T: ~const Bar>();
    |             ^^^^^^^^^^ required by this bound in `Foo::c`
 help: consider further restricting this bound
    |
-LL | fn test3<T: Foo + Bar>() {
+LL | fn test1<T: Foo + Bar>() {
    |                 +++++
 
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc1623-2.stderr b/src/test/ui/rfc1623-2.stderr
index 495d45e22341..945c6533c797 100644
--- a/src/test/ui/rfc1623-2.stderr
+++ b/src/test/ui/rfc1623-2.stderr
@@ -23,7 +23,7 @@ help: consider making the type lifetime-generic with a new `'a` lifetime
 LL |     &(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
    |                       +++++++     ++      ++         ++
 
-error[E0605]: non-primitive cast: `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {non_elidable}` as `for<'r, 's> fn(&'r u8, &'s u8) -> &u8`
+error[E0605]: non-primitive cast: `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8 {non_elidable}` as `for<'a, 'b> fn(&'a u8, &'b u8) -> &u8`
   --> $DIR/rfc1623-2.rs:10:6
    |
 LL |     &(non_elidable as fn(&u8, &u8) -> &u8);
diff --git a/src/test/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr b/src/test/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr
index 94a90a568548..fc7bf22775dd 100644
--- a/src/test/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr
+++ b/src/test/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr
@@ -6,7 +6,7 @@ LL |     call(foo);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `Fn<()>` is not implemented for `fn() {foo}`
+   = help: the trait `Fn<()>` is not implemented for fn item `fn() {foo}`
    = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call`
@@ -23,7 +23,7 @@ LL |     call_mut(foo);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `FnMut<()>` is not implemented for `fn() {foo}`
+   = help: the trait `FnMut<()>` is not implemented for fn item `fn() {foo}`
    = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_mut`
@@ -40,7 +40,7 @@ LL |     call_once(foo);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `FnOnce<()>` is not implemented for `fn() {foo}`
+   = help: the trait `FnOnce<()>` is not implemented for fn item `fn() {foo}`
    = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_once`
@@ -57,7 +57,7 @@ LL |     call(foo_unsafe);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `Fn<()>` is not implemented for `unsafe fn() {foo_unsafe}`
+   = help: the trait `Fn<()>` is not implemented for fn item `unsafe fn() {foo_unsafe}`
    = note: wrap the `unsafe fn() {foo_unsafe}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call`
@@ -74,7 +74,7 @@ LL |     call_mut(foo_unsafe);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `FnMut<()>` is not implemented for `unsafe fn() {foo_unsafe}`
+   = help: the trait `FnMut<()>` is not implemented for fn item `unsafe fn() {foo_unsafe}`
    = note: wrap the `unsafe fn() {foo_unsafe}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_mut`
@@ -91,7 +91,7 @@ LL |     call_once(foo_unsafe);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `FnOnce<()>` is not implemented for `unsafe fn() {foo_unsafe}`
+   = help: the trait `FnOnce<()>` is not implemented for fn item `unsafe fn() {foo_unsafe}`
    = note: wrap the `unsafe fn() {foo_unsafe}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_once`
diff --git a/src/test/ui/rfcs/rfc1857-drop-order.rs b/src/test/ui/rfcs/rfc1857-drop-order.rs
index 243b7fb6fade..4c4816c2fbc8 100644
--- a/src/test/ui/rfcs/rfc1857-drop-order.rs
+++ b/src/test/ui/rfcs/rfc1857-drop-order.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![allow(dead_code, unreachable_code)]
 
diff --git a/src/test/ui/runtime/backtrace-debuginfo.rs b/src/test/ui/runtime/backtrace-debuginfo.rs
index 7c9f1a7f2f49..8b5466b6cfa0 100644
--- a/src/test/ui/runtime/backtrace-debuginfo.rs
+++ b/src/test/ui/runtime/backtrace-debuginfo.rs
@@ -12,6 +12,7 @@
 // ignore-pretty issue #37195
 // ignore-emscripten spawning processes is not supported
 // ignore-sgx no processes
+// ignore-fuchsia Backtrace not symbolized, trace different line alignment
 
 use std::env;
 
diff --git a/src/test/ui/runtime/out-of-stack.rs b/src/test/ui/runtime/out-of-stack.rs
index 73c31cd9721f..6873abc49b24 100644
--- a/src/test/ui/runtime/out-of-stack.rs
+++ b/src/test/ui/runtime/out-of-stack.rs
@@ -5,6 +5,7 @@
 // ignore-android: FIXME (#20004)
 // ignore-emscripten no processes
 // ignore-sgx no processes
+// ignore-fuchsia must translate zircon signal to SIGABRT, FIXME (#58590)
 
 #![feature(core_intrinsics)]
 #![feature(rustc_private)]
diff --git a/src/test/ui/runtime/rt-explody-panic-payloads.rs b/src/test/ui/runtime/rt-explody-panic-payloads.rs
index eb5bf8f67a84..e2221e5df8ea 100644
--- a/src/test/ui/runtime/rt-explody-panic-payloads.rs
+++ b/src/test/ui/runtime/rt-explody-panic-payloads.rs
@@ -2,9 +2,6 @@
 // needs-unwind
 // ignore-emscripten no processes
 // ignore-sgx no processes
-// ignore-wasm32-bare no unwinding panic
-// ignore-avr no unwinding panic
-// ignore-nvptx64 no unwinding panic
 
 use std::env;
 use std::process::Command;
diff --git a/src/test/ui/rust-2021/reserved-prefixes-migration.stderr b/src/test/ui/rust-2021/reserved-prefixes-migration.stderr
index 647a9f393125..c6bc082cf18d 100644
--- a/src/test/ui/rust-2021/reserved-prefixes-migration.stderr
+++ b/src/test/ui/rust-2021/reserved-prefixes-migration.stderr
@@ -13,9 +13,8 @@ LL | #![warn(rust_2021_prefixes_incompatible_syntax)]
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/reserving-syntax.html>
 help: insert whitespace here to avoid this being parsed as a prefix in Rust 2021
    |
-LL -     m2!(z"hey");
-LL +     m2!(z "hey");
-   |
+LL |     m2!(z "hey");
+   |          +
 
 warning: prefix `prefix` is unknown
   --> $DIR/reserved-prefixes-migration.rs:19:9
@@ -27,9 +26,8 @@ LL |     m2!(prefix"hey");
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/reserving-syntax.html>
 help: insert whitespace here to avoid this being parsed as a prefix in Rust 2021
    |
-LL -     m2!(prefix"hey");
-LL +     m2!(prefix "hey");
-   |
+LL |     m2!(prefix "hey");
+   |               +
 
 warning: prefix `hey` is unknown
   --> $DIR/reserved-prefixes-migration.rs:22:9
@@ -41,9 +39,8 @@ LL |     m3!(hey#123);
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/reserving-syntax.html>
 help: insert whitespace here to avoid this being parsed as a prefix in Rust 2021
    |
-LL -     m3!(hey#123);
-LL +     m3!(hey #123);
-   |
+LL |     m3!(hey #123);
+   |            +
 
 warning: prefix `hey` is unknown
   --> $DIR/reserved-prefixes-migration.rs:25:9
@@ -55,9 +52,8 @@ LL |     m3!(hey#hey);
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/reserving-syntax.html>
 help: insert whitespace here to avoid this being parsed as a prefix in Rust 2021
    |
-LL -     m3!(hey#hey);
-LL +     m3!(hey #hey);
-   |
+LL |     m3!(hey #hey);
+   |            +
 
 warning: prefix `kind` is unknown
   --> $DIR/reserved-prefixes-migration.rs:35:14
@@ -69,9 +65,8 @@ LL |     #name = #kind#value
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/reserving-syntax.html>
 help: insert whitespace here to avoid this being parsed as a prefix in Rust 2021
    |
-LL -     #name = #kind#value
-LL +     #name = #kind #value
-   |
+LL |     #name = #kind #value
+   |                  +
 
 warning: 5 warnings emitted
 
diff --git a/src/test/ui/rust-2021/reserved-prefixes.stderr b/src/test/ui/rust-2021/reserved-prefixes.stderr
index df31aee66fea..807d6d98bd3c 100644
--- a/src/test/ui/rust-2021/reserved-prefixes.stderr
+++ b/src/test/ui/rust-2021/reserved-prefixes.stderr
@@ -7,9 +7,8 @@ LL |     demo3!(foo#bar);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo3!(foo#bar);
-LL +     demo3!(foo #bar);
-   |
+LL |     demo3!(foo #bar);
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:17:12
@@ -20,9 +19,8 @@ LL |     demo2!(foo"bar");
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo2!(foo"bar");
-LL +     demo2!(foo "bar");
-   |
+LL |     demo2!(foo "bar");
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:18:12
@@ -33,9 +31,8 @@ LL |     demo2!(foo'b');
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo2!(foo'b');
-LL +     demo2!(foo 'b');
-   |
+LL |     demo2!(foo 'b');
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:20:12
@@ -46,9 +43,8 @@ LL |     demo2!(foo'b);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo2!(foo'b);
-LL +     demo2!(foo 'b);
-   |
+LL |     demo2!(foo 'b);
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:21:12
@@ -59,9 +55,8 @@ LL |     demo3!(foo# bar);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo3!(foo# bar);
-LL +     demo3!(foo # bar);
-   |
+LL |     demo3!(foo # bar);
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:22:12
@@ -72,9 +67,8 @@ LL |     demo4!(foo#! bar);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo4!(foo#! bar);
-LL +     demo4!(foo #! bar);
-   |
+LL |     demo4!(foo #! bar);
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:23:12
@@ -85,9 +79,8 @@ LL |     demo4!(foo## bar);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo4!(foo## bar);
-LL +     demo4!(foo ## bar);
-   |
+LL |     demo4!(foo ## bar);
+   |               +
 
 error: prefix `foo` is unknown
   --> $DIR/reserved-prefixes.rs:25:12
@@ -98,9 +91,8 @@ LL |     demo4!(foo#bar#);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo4!(foo#bar#);
-LL +     demo4!(foo #bar#);
-   |
+LL |     demo4!(foo #bar#);
+   |               +
 
 error: prefix `bar` is unknown
   --> $DIR/reserved-prefixes.rs:25:16
@@ -111,9 +103,8 @@ LL |     demo4!(foo#bar#);
    = note: prefixed identifiers and literals are reserved since Rust 2021
 help: consider inserting whitespace here
    |
-LL -     demo4!(foo#bar#);
-LL +     demo4!(foo#bar #);
-   |
+LL |     demo4!(foo#bar #);
+   |                   +
 
 error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/sanitize/memory-eager.rs b/src/test/ui/sanitize/memory-eager.rs
new file mode 100644
index 000000000000..cc0593ec07dc
--- /dev/null
+++ b/src/test/ui/sanitize/memory-eager.rs
@@ -0,0 +1,38 @@
+// needs-sanitizer-support
+// needs-sanitizer-memory
+// min-llvm-version: 14.0.0
+//
+// revisions: unoptimized optimized
+//
+// [optimized]compile-flags: -Z sanitizer=memory -Zsanitizer-memory-track-origins -O
+// [unoptimized]compile-flags: -Z sanitizer=memory -Zsanitizer-memory-track-origins
+//
+// run-fail
+// error-pattern: MemorySanitizer: use-of-uninitialized-value
+// error-pattern: Uninitialized value was created by an allocation
+// error-pattern: in the stack frame
+//
+// This test case intentionally limits the usage of the std,
+// since it will be linked with an uninstrumented version of it.
+
+#![feature(core_intrinsics)]
+#![feature(start)]
+#![feature(bench_black_box)]
+
+use std::hint::black_box;
+use std::mem::MaybeUninit;
+
+#[inline(never)]
+#[no_mangle]
+#[allow(invalid_value)]
+fn random() -> char {
+    let r = unsafe { MaybeUninit::uninit().assume_init() };
+    // Avoid optimizing everything out.
+    black_box(r)
+}
+
+#[start]
+fn main(_: isize, _: *const *const u8) -> isize {
+    random();
+    0
+}
diff --git a/src/test/ui/sanitize/memory.rs b/src/test/ui/sanitize/memory.rs
index adda51f6be0e..14d4de65dd37 100644
--- a/src/test/ui/sanitize/memory.rs
+++ b/src/test/ui/sanitize/memory.rs
@@ -1,7 +1,10 @@
 // needs-sanitizer-support
 // needs-sanitizer-memory
 //
-// compile-flags: -Z sanitizer=memory -Zsanitizer-memory-track-origins -O
+// revisions: unoptimized optimized
+//
+// [optimized]compile-flags: -Z sanitizer=memory -Zsanitizer-memory-track-origins -O
+// [unoptimized]compile-flags: -Z sanitizer=memory -Zsanitizer-memory-track-origins
 //
 // run-fail
 // error-pattern: MemorySanitizer: use-of-uninitialized-value
@@ -22,9 +25,9 @@ use std::mem::MaybeUninit;
 #[inline(never)]
 #[no_mangle]
 fn random() -> [isize; 32] {
-    let r = unsafe { MaybeUninit::uninit().assume_init() };
+    let r = MaybeUninit::uninit();
     // Avoid optimizing everything out.
-    black_box(r)
+    unsafe { std::intrinsics::volatile_load(r.as_ptr()) }
 }
 
 #[inline(never)]
@@ -39,6 +42,6 @@ fn xor(a: &[isize]) -> isize {
 
 #[start]
 fn main(_: isize, _: *const *const u8) -> isize {
-    let r = random();
+    let r = black_box(random as fn() -> [isize; 32])();
     xor(&r)
 }
diff --git a/src/test/ui/sanitize/new-llvm-pass-manager-thin-lto.rs b/src/test/ui/sanitize/new-llvm-pass-manager-thin-lto.rs
index 1542c7f31184..33e18e35522e 100644
--- a/src/test/ui/sanitize/new-llvm-pass-manager-thin-lto.rs
+++ b/src/test/ui/sanitize/new-llvm-pass-manager-thin-lto.rs
@@ -7,7 +7,7 @@
 //
 // no-prefer-dynamic
 // revisions: opt0 opt1
-// compile-flags: -Znew-llvm-pass-manager=yes -Zsanitizer=address -Clto=thin
+// compile-flags: -Zsanitizer=address -Clto=thin
 //[opt0]compile-flags: -Copt-level=0
 //[opt1]compile-flags: -Copt-level=1
 // run-fail
diff --git a/src/test/ui/simd/intrinsic/ptr-cast.rs b/src/test/ui/simd/intrinsic/ptr-cast.rs
new file mode 100644
index 000000000000..1d13720bcd31
--- /dev/null
+++ b/src/test/ui/simd/intrinsic/ptr-cast.rs
@@ -0,0 +1,33 @@
+// run-pass
+
+#![feature(repr_simd, platform_intrinsics)]
+
+extern "platform-intrinsic" {
+    fn simd_cast_ptr<T, U>(x: T) -> U;
+    fn simd_expose_addr<T, U>(x: T) -> U;
+    fn simd_from_exposed_addr<T, U>(x: T) -> U;
+}
+
+#[derive(Copy, Clone)]
+#[repr(simd)]
+struct V<T>([T; 2]);
+
+fn main() {
+    unsafe {
+        let mut foo = 4i8;
+        let ptr = &mut foo as *mut i8;
+
+        let ptrs = V::<*mut i8>([ptr, core::ptr::null_mut()]);
+
+        // change constness and type
+        let const_ptrs: V<*const u8> = simd_cast_ptr(ptrs);
+
+        let exposed_addr: V<usize> = simd_expose_addr(const_ptrs);
+
+        let from_exposed_addr: V<*mut i8> = simd_from_exposed_addr(exposed_addr);
+
+        assert!(const_ptrs.0 == [ptr as *const u8, core::ptr::null()]);
+        assert!(exposed_addr.0 == [ptr as usize, 0]);
+        assert!(from_exposed_addr.0 == ptrs.0);
+    }
+}
diff --git a/src/test/ui/span/E0204.stderr b/src/test/ui/span/E0204.stderr
index 257584843520..0b2166eed7ea 100644
--- a/src/test/ui/span/E0204.stderr
+++ b/src/test/ui/span/E0204.stderr
@@ -1,11 +1,11 @@
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/E0204.rs:5:6
+  --> $DIR/E0204.rs:5:15
    |
 LL |     foo: Vec<u32>,
    |     ------------- this field does not implement `Copy`
 ...
 LL | impl Copy for Foo { }
-   |      ^^^^
+   |               ^^^
 
 error[E0204]: the trait `Copy` may not be implemented for this type
   --> $DIR/E0204.rs:7:10
@@ -19,13 +19,13 @@ LL |     ty: &'a mut bool,
    = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/E0204.rs:17:6
+  --> $DIR/E0204.rs:17:15
    |
 LL |     Bar { x: Vec<u32> },
    |           ----------- this field does not implement `Copy`
 ...
 LL | impl Copy for EFoo { }
-   |      ^^^^
+   |               ^^^^
 
 error[E0204]: the trait `Copy` may not be implemented for this type
   --> $DIR/E0204.rs:19:10
diff --git a/src/test/ui/span/E0493.rs b/src/test/ui/span/E0493.rs
index ad4100205f27..625da25a7c2c 100644
--- a/src/test/ui/span/E0493.rs
+++ b/src/test/ui/span/E0493.rs
@@ -15,7 +15,7 @@ impl Drop for Bar {
 }
 
 const F : Foo = (Foo { a : 0 }, Foo { a : 1 }).1;
-//~^ destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 fn main() {
 }
diff --git a/src/test/ui/span/E0493.stderr b/src/test/ui/span/E0493.stderr
index 29d1b0009432..9db627562d6e 100644
--- a/src/test/ui/span/E0493.stderr
+++ b/src/test/ui/span/E0493.stderr
@@ -1,10 +1,10 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(Foo, Foo)` cannot be evaluated at compile-time
   --> $DIR/E0493.rs:17:17
    |
 LL | const F : Foo = (Foo { a : 0 }, Foo { a : 1 }).1;
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - value is dropped here
    |                 |
-   |                 constants cannot evaluate destructors
+   |                 the destructor for this type cannot be evaluated in constants
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/span/E0535.stderr b/src/test/ui/span/E0535.stderr
index f52c3f9f2c04..b1411bc436ae 100644
--- a/src/test/ui/span/E0535.stderr
+++ b/src/test/ui/span/E0535.stderr
@@ -3,6 +3,8 @@ error[E0535]: invalid argument
    |
 LL | #[inline(unknown)]
    |          ^^^^^^^
+   |
+   = help: valid inline arguments are `always` and `never`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs b/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs
index b280c8ab6e2b..94f578af209a 100644
--- a/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs
+++ b/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs
@@ -12,7 +12,8 @@ impl A {
 
 trait C{async fn new(val: T) {} //~ ERROR  `async fn` is not permitted in Rust 2015
 //~^ ERROR functions in traits cannot be declared `async`
-//~^^ ERROR cannot find type `T` in this scope
-//~^^^ WARN changes to closure capture in Rust 2021 will affect drop order [rust_2021_incompatible_closure_captures]
+//~| ERROR mismatched types
+//~| ERROR cannot find type `T` in this scope
+//~| WARN changes to closure capture in Rust 2021 will affect drop order [rust_2021_incompatible_closure_captures]
 
 //~ ERROR  this file contains an unclosed delimiter
diff --git a/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.stderr b/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.stderr
index 50de2322907e..2c1fa7b36b60 100644
--- a/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.stderr
+++ b/src/test/ui/span/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.stderr
@@ -1,5 +1,5 @@
 error: this file contains an unclosed delimiter
-  --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:18:53
+  --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:19:53
    |
 LL | trait C{async fn new(val: T) {}
    |        - unclosed delimiter
@@ -25,17 +25,6 @@ LL | trait C{async fn new(val: T) {}
    = help: pass `--edition 2021` to `rustc`
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:13:9
-   |
-LL | trait C{async fn new(val: T) {}
-   |         -----^^^^^^^^^^^^^^^^^^
-   |         |
-   |         `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 error[E0423]: expected function, found module `crate`
   --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:9:5
    |
@@ -51,6 +40,19 @@ LL | pub struct A {}
 LL | trait C{async fn new(val: T) {}
    |                           ^ help: a struct with a similar name exists: `A`
 
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:13:9
+   |
+LL | trait C{async fn new(val: T) {}
+   |         -----^^^^^^^^^^^^^^^
+   |         |
+   |         `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
 warning: changes to closure capture in Rust 2021 will affect drop order
   --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:6:57
    |
@@ -72,6 +74,20 @@ help: add a dummy let to cause `path` to be fully captured
 LL |     async fn create(path: impl AsRef<std::path::Path>)  { let _ = &path;
    |                                                           ++++++++++++++
 
+error[E0308]: mismatched types
+  --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:13:30
+   |
+LL | trait C{async fn new(val: T) {}
+   |                              ^^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                           ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:13:30>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
 warning: changes to closure capture in Rust 2021 will affect drop order
   --> $DIR/drop-location-span-error-rust-2021-incompatible-closure-captures-93117.rs:13:30
    |
@@ -87,7 +103,7 @@ help: add a dummy let to cause `val` to be fully captured
 LL | trait C{async fn new(val: T) { let _ = &val;}
    |                                +++++++++++++
 
-error: aborting due to 6 previous errors; 2 warnings emitted
+error: aborting due to 7 previous errors; 2 warnings emitted
 
-Some errors have detailed explanations: E0412, E0423, E0670, E0706.
-For more information about an error, try `rustc --explain E0412`.
+Some errors have detailed explanations: E0308, E0412, E0423, E0670, E0706.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/span/issue-34264.stderr b/src/test/ui/span/issue-34264.stderr
index 28a911d0c5bf..15179954adcd 100644
--- a/src/test/ui/span/issue-34264.stderr
+++ b/src/test/ui/span/issue-34264.stderr
@@ -64,7 +64,7 @@ LL | fn foo(Option<i32>, String) {}
 help: remove the extra argument
    |
 LL |     foo(Some(42), 2);
-   |     ~~~~~~~~~~~~~~~~
+   |        ~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/issue-34264.rs:8:13
@@ -94,7 +94,7 @@ LL | fn bar(x, y: usize) {}
 help: remove the extra argument
    |
 LL |     bar(1, 2);
-   |     ~~~~~~~~~
+   |        ~~~~~~
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/span/issue-35987.stderr b/src/test/ui/span/issue-35987.stderr
index ea9c4c82c361..d8fddc8007f5 100644
--- a/src/test/ui/span/issue-35987.stderr
+++ b/src/test/ui/span/issue-35987.stderr
@@ -4,7 +4,7 @@ error[E0404]: expected trait, found type parameter `Add`
 LL | impl<T: Clone, Add> Add for Foo<T> {
    |                ---  ^^^ not a trait
    |                |
-   |                found this type pararmeter
+   |                found this type parameter
    |
 help: consider importing this trait instead
    |
diff --git a/src/test/ui/span/missing-unit-argument.stderr b/src/test/ui/span/missing-unit-argument.stderr
index d2afd277ecf7..b76a3ab307ae 100644
--- a/src/test/ui/span/missing-unit-argument.stderr
+++ b/src/test/ui/span/missing-unit-argument.stderr
@@ -12,7 +12,7 @@ LL |     Ok(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: provide the argument
    |
 LL |     let _: Result<(), String> = Ok(());
-   |                                 ~~~~~~
+   |                                   ~~~~
 
 error[E0061]: this function takes 2 arguments but 0 arguments were supplied
   --> $DIR/missing-unit-argument.rs:12:5
@@ -28,7 +28,7 @@ LL | fn foo(():(), ():()) {}
 help: provide the arguments
    |
 LL |     foo((), ());
-   |     ~~~~~~~~~~~
+   |        ~~~~~~~~
 
 error[E0061]: this function takes 2 arguments but 1 argument was supplied
   --> $DIR/missing-unit-argument.rs:13:5
@@ -44,7 +44,7 @@ LL | fn foo(():(), ():()) {}
 help: provide the argument
    |
 LL |     foo((), ());
-   |     ~~~~~~~~~~~
+   |        ~~~~~~~~
 
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/missing-unit-argument.rs:14:5
@@ -60,7 +60,7 @@ LL | fn bar(():()) {}
 help: provide the argument
    |
 LL |     bar(());
-   |     ~~~~~~~
+   |        ~~~~
 
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/missing-unit-argument.rs:15:7
@@ -76,7 +76,7 @@ LL |     fn baz(self, (): ()) { }
 help: provide the argument
    |
 LL |     S.baz(());
-   |       ~~~~~~~
+   |          ~~~~
 
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
   --> $DIR/missing-unit-argument.rs:16:7
@@ -92,7 +92,7 @@ LL |     fn generic<T>(self, _: T) { }
 help: provide the argument
    |
 LL |     S.generic::<()>(());
-   |       ~~~~~~~~~~~~~~~~~
+   |                    ~~~~
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/specialization/const_trait_impl.rs b/src/test/ui/specialization/const_trait_impl.rs
new file mode 100644
index 000000000000..05ba4c8d45d5
--- /dev/null
+++ b/src/test/ui/specialization/const_trait_impl.rs
@@ -0,0 +1,55 @@
+// check-pass
+#![feature(const_trait_impl, min_specialization, rustc_attrs)]
+
+#[rustc_specialization_trait]
+#[const_trait]
+pub unsafe trait Sup {
+    fn foo() -> u32;
+}
+
+#[rustc_specialization_trait]
+#[const_trait]
+pub unsafe trait Sub: ~const Sup {}
+
+unsafe impl const Sup for u8 {
+    default fn foo() -> u32 {
+        1
+    }
+}
+
+unsafe impl const Sup for () {
+    fn foo() -> u32 {
+        42
+    }
+}
+
+unsafe impl const Sub for () {}
+
+#[const_trait]
+pub trait A {
+    fn a() -> u32;
+}
+
+impl<T: ~const Default> const A for T {
+    default fn a() -> u32 {
+        2
+    }
+}
+
+impl<T: ~const Default + ~const Sup> const A for T {
+    default fn a() -> u32 {
+        3
+    }
+}
+
+impl<T: ~const Default + ~const Sub> const A for T {
+    fn a() -> u32 {
+        T::foo()
+    }
+}
+
+const _: () = assert!(<()>::a() == 42);
+const _: () = assert!(<u8>::a() == 3);
+const _: () = assert!(<u16>::a() == 2);
+
+fn main() {}
diff --git a/src/test/ui/specialization/default-generic-associated-type-bound.rs b/src/test/ui/specialization/default-generic-associated-type-bound.rs
index 0f5714e996a1..31a0685d004b 100644
--- a/src/test/ui/specialization/default-generic-associated-type-bound.rs
+++ b/src/test/ui/specialization/default-generic-associated-type-bound.rs
@@ -1,8 +1,7 @@
 // Check that default generics associated types are validated.
 
 #![feature(specialization)]
-#![feature(generic_associated_types)]
-//~^^ WARNING `specialization` is incomplete
+//~^ WARNING `specialization` is incomplete
 
 trait X {
     type U<'a>: PartialEq<&'a Self> where Self: 'a;
diff --git a/src/test/ui/specialization/default-generic-associated-type-bound.stderr b/src/test/ui/specialization/default-generic-associated-type-bound.stderr
index 6d98763a572f..44c24c1e578a 100644
--- a/src/test/ui/specialization/default-generic-associated-type-bound.stderr
+++ b/src/test/ui/specialization/default-generic-associated-type-bound.stderr
@@ -9,14 +9,14 @@ LL | #![feature(specialization)]
    = help: consider using `min_specialization` instead, which is more stable and complete
 
 error[E0277]: can't compare `T` with `T`
-  --> $DIR/default-generic-associated-type-bound.rs:18:26
+  --> $DIR/default-generic-associated-type-bound.rs:17:26
    |
 LL |     default type U<'a> = &'a T;
    |                          ^^^^^ no implementation for `T == T`
    |
    = note: required for `&'a T` to implement `PartialEq`
 note: required by a bound in `X::U`
-  --> $DIR/default-generic-associated-type-bound.rs:8:17
+  --> $DIR/default-generic-associated-type-bound.rs:7:17
    |
 LL |     type U<'a>: PartialEq<&'a Self> where Self: 'a;
    |                 ^^^^^^^^^^^^^^^^^^^ required by this bound in `X::U`
diff --git a/src/test/ui/specialization/issue-33017.rs b/src/test/ui/specialization/issue-33017.rs
index 4d19230df6ba..8dbadf58d5c8 100644
--- a/src/test/ui/specialization/issue-33017.rs
+++ b/src/test/ui/specialization/issue-33017.rs
@@ -1,4 +1,4 @@
-// Test to ensure that trait bounds are propertly
+// Test to ensure that trait bounds are properly
 // checked on specializable associated types
 
 #![allow(incomplete_features)]
diff --git a/src/test/ui/specialization/issue-38091-2.stderr b/src/test/ui/specialization/issue-38091-2.stderr
index 146a56358beb..31ae4b26e45d 100644
--- a/src/test/ui/specialization/issue-38091-2.stderr
+++ b/src/test/ui/specialization/issue-38091-2.stderr
@@ -10,7 +10,7 @@ LL | #![feature(specialization)]
 
 error[E0275]: overflow evaluating the requirement `i32: Check`
    |
-note: required for `i32` to implement `Iterate`
+note: required for `i32` to implement `Iterate<'_>`
   --> $DIR/issue-38091-2.rs:11:13
    |
 LL | impl<'a, T> Iterate<'a> for T
diff --git a/src/test/ui/stability-attribute/missing-const-stability.rs b/src/test/ui/stability-attribute/missing-const-stability.rs
index d89886af314a..6eff899bfbf1 100644
--- a/src/test/ui/stability-attribute/missing-const-stability.rs
+++ b/src/test/ui/stability-attribute/missing-const-stability.rs
@@ -19,6 +19,7 @@ impl Foo {
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
+#[const_trait]
 pub trait Bar {
     #[stable(feature = "stable", since = "1.0.0")]
     fn fun();
diff --git a/src/test/ui/stability-attribute/missing-const-stability.stderr b/src/test/ui/stability-attribute/missing-const-stability.stderr
index 10978728fa36..4cfbe152891b 100644
--- a/src/test/ui/stability-attribute/missing-const-stability.stderr
+++ b/src/test/ui/stability-attribute/missing-const-stability.stderr
@@ -5,7 +5,7 @@ LL | pub const fn foo() {}
    | ^^^^^^^^^^^^^^^^^^^^^
 
 error: implementation has missing const stability attribute
-  --> $DIR/missing-const-stability.rs:27:1
+  --> $DIR/missing-const-stability.rs:28:1
    |
 LL | / impl const Bar for Foo {
 LL | |
diff --git a/src/test/ui/static/static-drop-scope.rs b/src/test/ui/static/static-drop-scope.rs
index e7ea8663d5af..34afa9873a38 100644
--- a/src/test/ui/static/static-drop-scope.rs
+++ b/src/test/ui/static/static-drop-scope.rs
@@ -5,33 +5,33 @@ impl Drop for WithDtor {
 }
 
 static PROMOTION_FAIL_S: Option<&'static WithDtor> = Some(&WithDtor);
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 //~| ERROR temporary value dropped while borrowed
 
 const PROMOTION_FAIL_C: Option<&'static WithDtor> = Some(&WithDtor);
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 //~| ERROR temporary value dropped while borrowed
 
 static EARLY_DROP_S: i32 = (WithDtor, 0).1;
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 const EARLY_DROP_C: i32 = (WithDtor, 0).1;
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 const fn const_drop<T>(_: T) {}
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 const fn const_drop2<T>(x: T) {
     (x, ()).1
-    //~^ ERROR destructors cannot be evaluated at compile-time
+    //~^ ERROR destructor of
 }
 
 const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 const HELPER: Option<WithDtor> = Some(WithDtor);
 
 const EARLY_DROP_C_OPTION_CONSTANT: i32 = (HELPER, 0).1;
-//~^ ERROR destructors cannot be evaluated at compile-time
+//~^ ERROR destructor of
 
 fn main () {}
diff --git a/src/test/ui/static/static-drop-scope.stderr b/src/test/ui/static/static-drop-scope.stderr
index ac32f217fd76..112bfc003048 100644
--- a/src/test/ui/static/static-drop-scope.stderr
+++ b/src/test/ui/static/static-drop-scope.stderr
@@ -1,10 +1,10 @@
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `WithDtor` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:7:60
    |
 LL | static PROMOTION_FAIL_S: Option<&'static WithDtor> = Some(&WithDtor);
    |                                                            ^^^^^^^^- value is dropped here
    |                                                            |
-   |                                                            statics cannot evaluate destructors
+   |                                                            the destructor for this type cannot be evaluated in statics
 
 error[E0716]: temporary value dropped while borrowed
   --> $DIR/static-drop-scope.rs:7:60
@@ -16,13 +16,13 @@ LL | static PROMOTION_FAIL_S: Option<&'static WithDtor> = Some(&WithDtor);
    |                                                      |     creates a temporary which is freed while still in use
    |                                                      using this value as a static requires that borrow lasts for `'static`
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `WithDtor` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:11:59
    |
 LL | const PROMOTION_FAIL_C: Option<&'static WithDtor> = Some(&WithDtor);
    |                                                           ^^^^^^^^- value is dropped here
    |                                                           |
-   |                                                           constants cannot evaluate destructors
+   |                                                           the destructor for this type cannot be evaluated in constants
 
 error[E0716]: temporary value dropped while borrowed
   --> $DIR/static-drop-scope.rs:11:59
@@ -34,54 +34,54 @@ LL | const PROMOTION_FAIL_C: Option<&'static WithDtor> = Some(&WithDtor);
    |                                                     |     creates a temporary which is freed while still in use
    |                                                     using this value as a constant requires that borrow lasts for `'static`
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(WithDtor, i32)` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:15:28
    |
 LL | static EARLY_DROP_S: i32 = (WithDtor, 0).1;
    |                            ^^^^^^^^^^^^^ - value is dropped here
    |                            |
-   |                            statics cannot evaluate destructors
+   |                            the destructor for this type cannot be evaluated in statics
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(WithDtor, i32)` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:18:27
    |
 LL | const EARLY_DROP_C: i32 = (WithDtor, 0).1;
    |                           ^^^^^^^^^^^^^ - value is dropped here
    |                           |
-   |                           constants cannot evaluate destructors
+   |                           the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `T` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:21:24
    |
 LL | const fn const_drop<T>(_: T) {}
    |                        ^      - value is dropped here
    |                        |
-   |                        constant functions cannot evaluate destructors
+   |                        the destructor for this type cannot be evaluated in constant functions
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(T, ())` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:25:5
    |
 LL |     (x, ()).1
-   |     ^^^^^^^ constant functions cannot evaluate destructors
+   |     ^^^^^^^ the destructor for this type cannot be evaluated in constant functions
 LL |
 LL | }
    | - value is dropped here
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(Option<WithDtor>, i32)` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:29:34
    |
 LL | const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
    |                                  ^^^^^^^^^^^^^^^^^^^ - value is dropped here
    |                                  |
-   |                                  constants cannot evaluate destructors
+   |                                  the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructors cannot be evaluated at compile-time
+error[E0493]: destructor of `(Option<WithDtor>, i32)` cannot be evaluated at compile-time
   --> $DIR/static-drop-scope.rs:34:43
    |
 LL | const EARLY_DROP_C_OPTION_CONSTANT: i32 = (HELPER, 0).1;
    |                                           ^^^^^^^^^^^ - value is dropped here
    |                                           |
-   |                                           constants cannot evaluate destructors
+   |                                           the destructor for this type cannot be evaluated in constants
 
 error: aborting due to 10 previous errors
 
diff --git a/src/test/ui/stats/hir-stats.rs b/src/test/ui/stats/hir-stats.rs
index a24b3ada57e5..5102574d4be3 100644
--- a/src/test/ui/stats/hir-stats.rs
+++ b/src/test/ui/stats/hir-stats.rs
@@ -1,6 +1,7 @@
 // check-pass
 // compile-flags: -Zhir-stats
 // only-x86_64
+// ignore-stage1
 
 // The aim here is to include at least one of every different type of top-level
 // AST/HIR node reported by `-Zhir-stats`.
diff --git a/src/test/ui/stats/hir-stats.stderr b/src/test/ui/stats/hir-stats.stderr
index eb828bb9a2c1..8d9776065308 100644
--- a/src/test/ui/stats/hir-stats.stderr
+++ b/src/test/ui/stats/hir-stats.stderr
@@ -1,151 +1,178 @@
-
-PRE EXPANSION AST STATS
-
-Name                Accumulated Size         Count     Item Size
-----------------------------------------------------------------
-ExprField                 48 ( 0.6%)             1            48
-Crate                     56 ( 0.7%)             1            56
-Attribute                 64 ( 0.8%)             2            32
-- Normal                    32 ( 0.4%)             1
-- DocComment                32 ( 0.4%)             1
-GenericArgs               64 ( 0.8%)             1            64
-- AngleBracketed            64 ( 0.8%)             1
-Local                     72 ( 0.9%)             1            72
-WherePredicate            72 ( 0.9%)             1            72
-- BoundPredicate            72 ( 0.9%)             1
-Arm                       96 ( 1.1%)             2            48
-ForeignItem               96 ( 1.1%)             1            96
-- Fn                        96 ( 1.1%)             1
-FieldDef                 160 ( 1.9%)             2            80
-Stmt                     160 ( 1.9%)             5            32
-- Local                     32 ( 0.4%)             1
-- MacCall                   32 ( 0.4%)             1
-- Expr                      96 ( 1.1%)             3
-Param                    160 ( 1.9%)             4            40
-FnDecl                   200 ( 2.4%)             5            40
-Variant                  240 ( 2.8%)             2           120
-Block                    288 ( 3.4%)             6            48
-GenericBound             352 ( 4.2%)             4            88
-- Trait                    352 ( 4.2%)             4
-AssocItem                416 ( 4.9%)             4           104
-- TyAlias                  208 ( 2.5%)             2
-- Fn                       208 ( 2.5%)             2
-GenericParam             520 ( 6.1%)             5           104
-PathSegment              720 ( 8.5%)            30            24
-Expr                     832 ( 9.8%)             8           104
-- Path                     104 ( 1.2%)             1
-- Match                    104 ( 1.2%)             1
-- Struct                   104 ( 1.2%)             1
-- Lit                      208 ( 2.5%)             2
-- Block                    312 ( 3.7%)             3
-Pat                      840 ( 9.9%)             7           120
-- Struct                   120 ( 1.4%)             1
-- Wild                     120 ( 1.4%)             1
-- Ident                    600 ( 7.1%)             5
-Ty                     1_344 (15.9%)            14            96
-- Rptr                      96 ( 1.1%)             1
-- Ptr                       96 ( 1.1%)             1
-- ImplicitSelf             192 ( 2.3%)             2
-- Path                     960 (11.4%)            10
-Item                   1_656 (19.6%)             9           184
-- Trait                    184 ( 2.2%)             1
-- Enum                     184 ( 2.2%)             1
-- ForeignMod               184 ( 2.2%)             1
-- Impl                     184 ( 2.2%)             1
-- Fn                       368 ( 4.4%)             2
-- Use                      552 ( 6.5%)             3
-----------------------------------------------------------------
-Total                  8_456
-
-
-POST EXPANSION AST STATS
-
-Name                Accumulated Size         Count     Item Size
-----------------------------------------------------------------
-ExprField                 48 ( 0.5%)             1            48
-Crate                     56 ( 0.6%)             1            56
-GenericArgs               64 ( 0.7%)             1            64
-- AngleBracketed            64 ( 0.7%)             1
-Local                     72 ( 0.8%)             1            72
-WherePredicate            72 ( 0.8%)             1            72
-- BoundPredicate            72 ( 0.8%)             1
-Arm                       96 ( 1.0%)             2            48
-ForeignItem               96 ( 1.0%)             1            96
-- Fn                        96 ( 1.0%)             1
-InlineAsm                120 ( 1.3%)             1           120
-Attribute                128 ( 1.4%)             4            32
-- DocComment                32 ( 0.3%)             1
-- Normal                    96 ( 1.0%)             3
-FieldDef                 160 ( 1.7%)             2            80
-Stmt                     160 ( 1.7%)             5            32
-- Local                     32 ( 0.3%)             1
-- Semi                      32 ( 0.3%)             1
-- Expr                      96 ( 1.0%)             3
-Param                    160 ( 1.7%)             4            40
-FnDecl                   200 ( 2.2%)             5            40
-Variant                  240 ( 2.6%)             2           120
-Block                    288 ( 3.1%)             6            48
-GenericBound             352 ( 3.8%)             4            88
-- Trait                    352 ( 3.8%)             4
-AssocItem                416 ( 4.5%)             4           104
-- TyAlias                  208 ( 2.3%)             2
-- Fn                       208 ( 2.3%)             2
-GenericParam             520 ( 5.7%)             5           104
-PathSegment              792 ( 8.6%)            33            24
-Pat                      840 ( 9.1%)             7           120
-- Struct                   120 ( 1.3%)             1
-- Wild                     120 ( 1.3%)             1
-- Ident                    600 ( 6.5%)             5
-Expr                     936 (10.2%)             9           104
-- Path                     104 ( 1.1%)             1
-- Match                    104 ( 1.1%)             1
-- Struct                   104 ( 1.1%)             1
-- InlineAsm                104 ( 1.1%)             1
-- Lit                      208 ( 2.3%)             2
-- Block                    312 ( 3.4%)             3
-Ty                     1_344 (14.6%)            14            96
-- Rptr                      96 ( 1.0%)             1
-- Ptr                       96 ( 1.0%)             1
-- ImplicitSelf             192 ( 2.1%)             2
-- Path                     960 (10.5%)            10
-Item                   2_024 (22.0%)            11           184
-- Trait                    184 ( 2.0%)             1
-- Enum                     184 ( 2.0%)             1
-- ExternCrate              184 ( 2.0%)             1
-- ForeignMod               184 ( 2.0%)             1
-- Impl                     184 ( 2.0%)             1
-- Fn                       368 ( 4.0%)             2
-- Use                      736 ( 8.0%)             4
-----------------------------------------------------------------
-Total                  9_184
-
-
-HIR STATS
-
-Name                Accumulated Size         Count     Item Size
-----------------------------------------------------------------
-Param                     64 ( 0.7%)             2            32
-Local                     64 ( 0.7%)             1            64
-ForeignItem               72 ( 0.8%)             1            72
-FieldDef                  96 ( 1.0%)             2            48
-Arm                       96 ( 1.0%)             2            48
-Stmt                      96 ( 1.0%)             3            32
-FnDecl                   120 ( 1.3%)             3            40
-Attribute                128 ( 1.4%)             4            32
-Lifetime                 128 ( 1.4%)             4            32
-Variant                  160 ( 1.7%)             2            80
-ImplItem                 176 ( 1.9%)             2            88
-GenericBound             192 ( 2.1%)             4            48
-TraitItem                192 ( 2.1%)             2            96
-WherePredicate           216 ( 2.3%)             3            72
-Block                    288 ( 3.1%)             6            48
-QPath                    408 ( 4.4%)            17            24
-Pat                      440 ( 4.8%)             5            88
-Expr                     672 ( 7.3%)            12            56
-Item                     960 (10.4%)            12            80
-Ty                     1_152 (12.4%)            16            72
-Path                   1_296 (14.0%)            27            48
-PathSegment            2_240 (24.2%)            40            56
-----------------------------------------------------------------
-Total                  9_256
-
+ast-stats-1 PRE EXPANSION AST STATS
+ast-stats-1 Name                Accumulated Size         Count     Item Size
+ast-stats-1 ----------------------------------------------------------------
+ast-stats-1 ExprField                 48 ( 0.6%)             1            48
+ast-stats-1 Crate                     56 ( 0.7%)             1            56
+ast-stats-1 Attribute                 64 ( 0.8%)             2            32
+ast-stats-1 - Normal                    32 ( 0.4%)             1
+ast-stats-1 - DocComment                32 ( 0.4%)             1
+ast-stats-1 GenericArgs               64 ( 0.8%)             1            64
+ast-stats-1 - AngleBracketed            64 ( 0.8%)             1
+ast-stats-1 Local                     72 ( 0.9%)             1            72
+ast-stats-1 WherePredicate            72 ( 0.9%)             1            72
+ast-stats-1 - BoundPredicate            72 ( 0.9%)             1
+ast-stats-1 Arm                       96 ( 1.1%)             2            48
+ast-stats-1 ForeignItem               96 ( 1.1%)             1            96
+ast-stats-1 - Fn                        96 ( 1.1%)             1
+ast-stats-1 FieldDef                 160 ( 1.9%)             2            80
+ast-stats-1 Stmt                     160 ( 1.9%)             5            32
+ast-stats-1 - Local                     32 ( 0.4%)             1
+ast-stats-1 - MacCall                   32 ( 0.4%)             1
+ast-stats-1 - Expr                      96 ( 1.1%)             3
+ast-stats-1 Param                    160 ( 1.9%)             4            40
+ast-stats-1 FnDecl                   200 ( 2.4%)             5            40
+ast-stats-1 Variant                  240 ( 2.9%)             2           120
+ast-stats-1 Block                    288 ( 3.4%)             6            48
+ast-stats-1 GenericBound             352 ( 4.2%)             4            88
+ast-stats-1 - Trait                    352 ( 4.2%)             4
+ast-stats-1 AssocItem                416 ( 4.9%)             4           104
+ast-stats-1 - TyAlias                  208 ( 2.5%)             2
+ast-stats-1 - Fn                       208 ( 2.5%)             2
+ast-stats-1 GenericParam             480 ( 5.7%)             5            96
+ast-stats-1 PathSegment              720 ( 8.6%)            30            24
+ast-stats-1 Expr                     832 ( 9.9%)             8           104
+ast-stats-1 - Path                     104 ( 1.2%)             1
+ast-stats-1 - Match                    104 ( 1.2%)             1
+ast-stats-1 - Struct                   104 ( 1.2%)             1
+ast-stats-1 - Lit                      208 ( 2.5%)             2
+ast-stats-1 - Block                    312 ( 3.7%)             3
+ast-stats-1 Pat                      840 (10.0%)             7           120
+ast-stats-1 - Struct                   120 ( 1.4%)             1
+ast-stats-1 - Wild                     120 ( 1.4%)             1
+ast-stats-1 - Ident                    600 ( 7.1%)             5
+ast-stats-1 Ty                     1_344 (16.0%)            14            96
+ast-stats-1 - Rptr                      96 ( 1.1%)             1
+ast-stats-1 - Ptr                       96 ( 1.1%)             1
+ast-stats-1 - ImplicitSelf             192 ( 2.3%)             2
+ast-stats-1 - Path                     960 (11.4%)            10
+ast-stats-1 Item                   1_656 (19.7%)             9           184
+ast-stats-1 - Trait                    184 ( 2.2%)             1
+ast-stats-1 - Enum                     184 ( 2.2%)             1
+ast-stats-1 - ForeignMod               184 ( 2.2%)             1
+ast-stats-1 - Impl                     184 ( 2.2%)             1
+ast-stats-1 - Fn                       368 ( 4.4%)             2
+ast-stats-1 - Use                      552 ( 6.6%)             3
+ast-stats-1 ----------------------------------------------------------------
+ast-stats-1 Total                  8_416
+ast-stats-1
+ast-stats-2 POST EXPANSION AST STATS
+ast-stats-2 Name                Accumulated Size         Count     Item Size
+ast-stats-2 ----------------------------------------------------------------
+ast-stats-2 ExprField                 48 ( 0.5%)             1            48
+ast-stats-2 Crate                     56 ( 0.6%)             1            56
+ast-stats-2 GenericArgs               64 ( 0.7%)             1            64
+ast-stats-2 - AngleBracketed            64 ( 0.7%)             1
+ast-stats-2 Local                     72 ( 0.8%)             1            72
+ast-stats-2 WherePredicate            72 ( 0.8%)             1            72
+ast-stats-2 - BoundPredicate            72 ( 0.8%)             1
+ast-stats-2 Arm                       96 ( 1.0%)             2            48
+ast-stats-2 ForeignItem               96 ( 1.0%)             1            96
+ast-stats-2 - Fn                        96 ( 1.0%)             1
+ast-stats-2 InlineAsm                120 ( 1.3%)             1           120
+ast-stats-2 Attribute                128 ( 1.4%)             4            32
+ast-stats-2 - DocComment                32 ( 0.3%)             1
+ast-stats-2 - Normal                    96 ( 1.0%)             3
+ast-stats-2 FieldDef                 160 ( 1.7%)             2            80
+ast-stats-2 Stmt                     160 ( 1.7%)             5            32
+ast-stats-2 - Local                     32 ( 0.3%)             1
+ast-stats-2 - Semi                      32 ( 0.3%)             1
+ast-stats-2 - Expr                      96 ( 1.0%)             3
+ast-stats-2 Param                    160 ( 1.7%)             4            40
+ast-stats-2 FnDecl                   200 ( 2.2%)             5            40
+ast-stats-2 Variant                  240 ( 2.6%)             2           120
+ast-stats-2 Block                    288 ( 3.1%)             6            48
+ast-stats-2 GenericBound             352 ( 3.8%)             4            88
+ast-stats-2 - Trait                    352 ( 3.8%)             4
+ast-stats-2 AssocItem                416 ( 4.5%)             4           104
+ast-stats-2 - TyAlias                  208 ( 2.3%)             2
+ast-stats-2 - Fn                       208 ( 2.3%)             2
+ast-stats-2 GenericParam             480 ( 5.2%)             5            96
+ast-stats-2 PathSegment              792 ( 8.7%)            33            24
+ast-stats-2 Pat                      840 ( 9.2%)             7           120
+ast-stats-2 - Struct                   120 ( 1.3%)             1
+ast-stats-2 - Wild                     120 ( 1.3%)             1
+ast-stats-2 - Ident                    600 ( 6.6%)             5
+ast-stats-2 Expr                     936 (10.2%)             9           104
+ast-stats-2 - Path                     104 ( 1.1%)             1
+ast-stats-2 - Match                    104 ( 1.1%)             1
+ast-stats-2 - Struct                   104 ( 1.1%)             1
+ast-stats-2 - InlineAsm                104 ( 1.1%)             1
+ast-stats-2 - Lit                      208 ( 2.3%)             2
+ast-stats-2 - Block                    312 ( 3.4%)             3
+ast-stats-2 Ty                     1_344 (14.7%)            14            96
+ast-stats-2 - Rptr                      96 ( 1.0%)             1
+ast-stats-2 - Ptr                       96 ( 1.0%)             1
+ast-stats-2 - ImplicitSelf             192 ( 2.1%)             2
+ast-stats-2 - Path                     960 (10.5%)            10
+ast-stats-2 Item                   2_024 (22.1%)            11           184
+ast-stats-2 - Trait                    184 ( 2.0%)             1
+ast-stats-2 - Enum                     184 ( 2.0%)             1
+ast-stats-2 - ExternCrate              184 ( 2.0%)             1
+ast-stats-2 - ForeignMod               184 ( 2.0%)             1
+ast-stats-2 - Impl                     184 ( 2.0%)             1
+ast-stats-2 - Fn                       368 ( 4.0%)             2
+ast-stats-2 - Use                      736 ( 8.0%)             4
+ast-stats-2 ----------------------------------------------------------------
+ast-stats-2 Total                  9_144
+ast-stats-2
+hir-stats HIR STATS
+hir-stats Name                Accumulated Size         Count     Item Size
+hir-stats ----------------------------------------------------------------
+hir-stats ForeignItemRef            24 ( 0.2%)             1            24
+hir-stats Lifetime                  32 ( 0.3%)             1            32
+hir-stats Mod                       32 ( 0.3%)             1            32
+hir-stats ExprField                 40 ( 0.4%)             1            40
+hir-stats TraitItemRef              56 ( 0.6%)             2            28
+hir-stats Local                     64 ( 0.7%)             1            64
+hir-stats Param                     64 ( 0.7%)             2            32
+hir-stats InlineAsm                 72 ( 0.7%)             1            72
+hir-stats ImplItemRef               72 ( 0.7%)             2            36
+hir-stats Body                      96 ( 1.0%)             3            32
+hir-stats GenericArg                96 ( 1.0%)             4            24
+hir-stats - Type                      24 ( 0.2%)             1
+hir-stats - Lifetime                  72 ( 0.7%)             3
+hir-stats FieldDef                  96 ( 1.0%)             2            48
+hir-stats Arm                       96 ( 1.0%)             2            48
+hir-stats Stmt                      96 ( 1.0%)             3            32
+hir-stats - Local                     32 ( 0.3%)             1
+hir-stats - Semi                      32 ( 0.3%)             1
+hir-stats - Expr                      32 ( 0.3%)             1
+hir-stats FnDecl                   120 ( 1.2%)             3            40
+hir-stats Attribute                128 ( 1.3%)             4            32
+hir-stats GenericArgs              144 ( 1.5%)             3            48
+hir-stats Variant                  160 ( 1.7%)             2            80
+hir-stats WherePredicate           168 ( 1.7%)             3            56
+hir-stats - BoundPredicate           168 ( 1.7%)             3
+hir-stats GenericBound             192 ( 2.0%)             4            48
+hir-stats - Trait                    192 ( 2.0%)             4
+hir-stats Block                    288 ( 3.0%)             6            48
+hir-stats Pat                      360 ( 3.7%)             5            72
+hir-stats - Wild                      72 ( 0.7%)             1
+hir-stats - Struct                    72 ( 0.7%)             1
+hir-stats - Binding                  216 ( 2.2%)             3
+hir-stats GenericParam             400 ( 4.1%)             5            80
+hir-stats Generics                 560 ( 5.8%)            10            56
+hir-stats Ty                       720 ( 7.4%)            15            48
+hir-stats - Ptr                       48 ( 0.5%)             1
+hir-stats - Rptr                      48 ( 0.5%)             1
+hir-stats - Path                     624 ( 6.4%)            13
+hir-stats Expr                     768 ( 7.9%)            12            64
+hir-stats - Path                      64 ( 0.7%)             1
+hir-stats - Struct                    64 ( 0.7%)             1
+hir-stats - Match                     64 ( 0.7%)             1
+hir-stats - InlineAsm                 64 ( 0.7%)             1
+hir-stats - Lit                      128 ( 1.3%)             2
+hir-stats - Block                    384 ( 4.0%)             6
+hir-stats Item                     960 ( 9.9%)            12            80
+hir-stats - Trait                     80 ( 0.8%)             1
+hir-stats - Enum                      80 ( 0.8%)             1
+hir-stats - ExternCrate               80 ( 0.8%)             1
+hir-stats - ForeignMod                80 ( 0.8%)             1
+hir-stats - Impl                      80 ( 0.8%)             1
+hir-stats - Fn                       160 ( 1.7%)             2
+hir-stats - Use                      400 ( 4.1%)             5
+hir-stats Path                   1_536 (15.9%)            32            48
+hir-stats PathSegment            2_240 (23.1%)            40            56
+hir-stats ----------------------------------------------------------------
+hir-stats Total                  9_680
+hir-stats
diff --git a/src/test/ui/std-backtrace.rs b/src/test/ui/std-backtrace.rs
index 3f8306baf8a2..59574b471dda 100644
--- a/src/test/ui/std-backtrace.rs
+++ b/src/test/ui/std-backtrace.rs
@@ -4,6 +4,7 @@
 // ignore-openbsd no support for libbacktrace without filename
 // ignore-sgx no processes
 // ignore-msvc see #62897 and `backtrace-debuginfo.rs` test
+// ignore-fuchsia Backtraces not symbolized
 // compile-flags:-g
 // compile-flags:-Cstrip=none
 
diff --git a/src/test/ui/structs-enums/type-sizes.rs b/src/test/ui/structs-enums/type-sizes.rs
index 73a11a5e743f..7a23f13630a4 100644
--- a/src/test/ui/structs-enums/type-sizes.rs
+++ b/src/test/ui/structs-enums/type-sizes.rs
@@ -120,6 +120,54 @@ pub enum AlwaysTaggedBecauseItHasNoNiche {
     B
 }
 
+pub enum NicheFilledMultipleFields {
+    A(bool, u8),
+    B(u8),
+    C(u8),
+    D(bool),
+    E,
+    F,
+    G,
+}
+
+struct BoolInTheMiddle(std::num::NonZeroU16, bool, u8);
+
+enum NicheWithData {
+    A,
+    B([u16; 5]),
+    Largest { a1: u32, a2: BoolInTheMiddle, a3: u32 },
+    C,
+    D(u32, u32),
+}
+
+// A type with almost 2^16 invalid values.
+#[repr(u16)]
+pub enum NicheU16 {
+    _0,
+}
+
+pub enum EnumManyVariant<X> {
+    Dataful(u8, X),
+
+    // 0x100 niche variants.
+    _00, _01, _02, _03, _04, _05, _06, _07, _08, _09, _0A, _0B, _0C, _0D, _0E, _0F,
+    _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _1A, _1B, _1C, _1D, _1E, _1F,
+    _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _2A, _2B, _2C, _2D, _2E, _2F,
+    _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _3A, _3B, _3C, _3D, _3E, _3F,
+    _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _4A, _4B, _4C, _4D, _4E, _4F,
+    _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _5A, _5B, _5C, _5D, _5E, _5F,
+    _60, _61, _62, _63, _64, _65, _66, _67, _68, _69, _6A, _6B, _6C, _6D, _6E, _6F,
+    _70, _71, _72, _73, _74, _75, _76, _77, _78, _79, _7A, _7B, _7C, _7D, _7E, _7F,
+    _80, _81, _82, _83, _84, _85, _86, _87, _88, _89, _8A, _8B, _8C, _8D, _8E, _8F,
+    _90, _91, _92, _93, _94, _95, _96, _97, _98, _99, _9A, _9B, _9C, _9D, _9E, _9F,
+    _A0, _A1, _A2, _A3, _A4, _A5, _A6, _A7, _A8, _A9, _AA, _AB, _AC, _AD, _AE, _AF,
+    _B0, _B1, _B2, _B3, _B4, _B5, _B6, _B7, _B8, _B9, _BA, _BB, _BC, _BD, _BE, _BF,
+    _C0, _C1, _C2, _C3, _C4, _C5, _C6, _C7, _C8, _C9, _CA, _CB, _CC, _CD, _CE, _CF,
+    _D0, _D1, _D2, _D3, _D4, _D5, _D6, _D7, _D8, _D9, _DA, _DB, _DC, _DD, _DE, _DF,
+    _E0, _E1, _E2, _E3, _E4, _E5, _E6, _E7, _E8, _E9, _EA, _EB, _EC, _ED, _EE, _EF,
+    _F0, _F1, _F2, _F3, _F4, _F5, _F6, _F7, _F8, _F9, _FA, _FB, _FC, _FD, _FE, _FF,
+}
+
 pub fn main() {
     assert_eq!(size_of::<u8>(), 1 as usize);
     assert_eq!(size_of::<u32>(), 4 as usize);
@@ -170,4 +218,35 @@ pub fn main() {
     assert_eq!(size_of::<AlwaysTaggedBecauseItHasNoNiche>(), 8);
     assert_eq!(size_of::<Option<AlwaysTaggedBecauseItHasNoNiche>>(), 8);
     assert_eq!(size_of::<Option<Option<AlwaysTaggedBecauseItHasNoNiche>>>(), 8);
+
+    assert_eq!(size_of::<NicheFilledMultipleFields>(), 2);
+    assert_eq!(size_of::<Option<NicheFilledMultipleFields>>(), 2);
+    assert_eq!(size_of::<Option<Option<NicheFilledMultipleFields>>>(), 2);
+
+    struct S1{ a: u16, b: std::num::NonZeroU16, c: u16, d: u8, e: u32, f: u64, g:[u8;2] }
+    assert_eq!(size_of::<S1>(), 24);
+    assert_eq!(size_of::<Option<S1>>(), 24);
+
+    assert_eq!(size_of::<NicheWithData>(), 12);
+    assert_eq!(size_of::<Option<NicheWithData>>(), 12);
+    assert_eq!(size_of::<Option<Option<NicheWithData>>>(), 12);
+    assert_eq!(
+        size_of::<Option<Option2<&(), Option<NicheWithData>>>>(),
+        size_of::<(&(), NicheWithData)>()
+    );
+
+    pub enum FillPadding { A(std::num::NonZeroU8, u32), B }
+    assert_eq!(size_of::<FillPadding>(), 8);
+    assert_eq!(size_of::<Option<FillPadding>>(), 8);
+    assert_eq!(size_of::<Option<Option<FillPadding>>>(), 8);
+
+    assert_eq!(size_of::<Result<(std::num::NonZeroU8, u8, u8), u16>>(), 4);
+    assert_eq!(size_of::<Option<Result<(std::num::NonZeroU8, u8, u8), u16>>>(), 4);
+    assert_eq!(size_of::<Result<(std::num::NonZeroU8, u8, u8, u8), u16>>(), 4);
+
+    assert_eq!(size_of::<EnumManyVariant<u16>>(), 6);
+    assert_eq!(size_of::<EnumManyVariant<NicheU16>>(), 4);
+    assert_eq!(size_of::<EnumManyVariant<Option<NicheU16>>>(), 4);
+    assert_eq!(size_of::<EnumManyVariant<Option2<NicheU16,u8>>>(), 6);
+    assert_eq!(size_of::<EnumManyVariant<Option<(NicheU16,u8)>>>(), 6);
 }
diff --git a/src/test/ui/structs/struct-path-associated-type.rs b/src/test/ui/structs/struct-path-associated-type.rs
index f88572f8419c..2dd7174a9bed 100644
--- a/src/test/ui/structs/struct-path-associated-type.rs
+++ b/src/test/ui/structs/struct-path-associated-type.rs
@@ -13,7 +13,7 @@ fn f<T: Tr>() {
     //~^ ERROR expected struct, variant or union type, found associated type
     let z = T::A::<u8> {};
     //~^ ERROR expected struct, variant or union type, found associated type
-    //~| ERROR type arguments are not allowed on this type
+    //~| ERROR this associated type takes 0 generic arguments but 1 generic argument was supplied
     match S {
         T::A {} => {}
         //~^ ERROR expected struct, variant or union type, found associated type
@@ -22,7 +22,7 @@ fn f<T: Tr>() {
 
 fn g<T: Tr<A = S>>() {
     let s = T::A {}; // OK
-    let z = T::A::<u8> {}; //~ ERROR type arguments are not allowed on this type
+    let z = T::A::<u8> {}; //~ ERROR this associated type takes 0 generic arguments but 1 generic argument was supplied
     match S {
         T::A {} => {} // OK
     }
diff --git a/src/test/ui/structs/struct-path-associated-type.stderr b/src/test/ui/structs/struct-path-associated-type.stderr
index bdce0e1b331b..abb445214f36 100644
--- a/src/test/ui/structs/struct-path-associated-type.stderr
+++ b/src/test/ui/structs/struct-path-associated-type.stderr
@@ -4,13 +4,19 @@ error[E0071]: expected struct, variant or union type, found associated type
 LL |     let s = T::A {};
    |             ^^^^ not a struct
 
-error[E0109]: type arguments are not allowed on this type
-  --> $DIR/struct-path-associated-type.rs:14:20
+error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/struct-path-associated-type.rs:14:16
    |
 LL |     let z = T::A::<u8> {};
-   |                -   ^^ type argument not allowed
+   |                ^------ help: remove these generics
    |                |
-   |                not allowed on this type
+   |                expected 0 generic arguments
+   |
+note: associated type defined here, with 0 generic parameters
+  --> $DIR/struct-path-associated-type.rs:4:10
+   |
+LL |     type A;
+   |          ^
 
 error[E0071]: expected struct, variant or union type, found associated type
   --> $DIR/struct-path-associated-type.rs:14:13
@@ -24,13 +30,19 @@ error[E0071]: expected struct, variant or union type, found associated type
 LL |         T::A {} => {}
    |         ^^^^ not a struct
 
-error[E0109]: type arguments are not allowed on this type
-  --> $DIR/struct-path-associated-type.rs:25:20
+error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/struct-path-associated-type.rs:25:16
    |
 LL |     let z = T::A::<u8> {};
-   |                -   ^^ type argument not allowed
+   |                ^------ help: remove these generics
    |                |
-   |                not allowed on this type
+   |                expected 0 generic arguments
+   |
+note: associated type defined here, with 0 generic parameters
+  --> $DIR/struct-path-associated-type.rs:4:10
+   |
+LL |     type A;
+   |          ^
 
 error[E0223]: ambiguous associated type
   --> $DIR/struct-path-associated-type.rs:32:13
@@ -52,5 +64,5 @@ LL |         S::A {} => {}
 
 error: aborting due to 8 previous errors
 
-Some errors have detailed explanations: E0071, E0109, E0223.
+Some errors have detailed explanations: E0071, E0107, E0223.
 For more information about an error, try `rustc --explain E0071`.
diff --git a/src/test/ui/suggestions/abi-typo.fixed b/src/test/ui/suggestions/abi-typo.fixed
new file mode 100644
index 000000000000..04d265865f0f
--- /dev/null
+++ b/src/test/ui/suggestions/abi-typo.fixed
@@ -0,0 +1,6 @@
+// run-rustfix
+extern "cdecl" fn cdedl() {} //~ ERROR invalid ABI
+
+fn main() {
+    cdedl();
+}
diff --git a/src/test/ui/suggestions/abi-typo.rs b/src/test/ui/suggestions/abi-typo.rs
new file mode 100644
index 000000000000..6d80db522ebc
--- /dev/null
+++ b/src/test/ui/suggestions/abi-typo.rs
@@ -0,0 +1,6 @@
+// run-rustfix
+extern "cdedl" fn cdedl() {} //~ ERROR invalid ABI
+
+fn main() {
+    cdedl();
+}
diff --git a/src/test/ui/suggestions/abi-typo.stderr b/src/test/ui/suggestions/abi-typo.stderr
new file mode 100644
index 000000000000..67a84f119f6c
--- /dev/null
+++ b/src/test/ui/suggestions/abi-typo.stderr
@@ -0,0 +1,14 @@
+error[E0703]: invalid ABI: found `cdedl`
+  --> $DIR/abi-typo.rs:2:8
+   |
+LL | extern "cdedl" fn cdedl() {}
+   |        ^^^^^^^
+   |        |
+   |        invalid ABI
+   |        help: did you mean: `"cdecl"`
+   |
+   = note: invoke `rustc --print=calling-conventions` for a full list of supported calling conventions.
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0703`.
diff --git a/src/test/ui/suggestions/args-instead-of-tuple-errors.stderr b/src/test/ui/suggestions/args-instead-of-tuple-errors.stderr
index 4c952669cfaf..0a91c442d2c6 100644
--- a/src/test/ui/suggestions/args-instead-of-tuple-errors.stderr
+++ b/src/test/ui/suggestions/args-instead-of-tuple-errors.stderr
@@ -19,7 +19,7 @@ LL |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: remove the extra argument
    |
 LL |     let _: Option<(i32, bool)> = Some(/* (i32, bool) */);
-   |                                  ~~~~~~~~~~~~~~~~~~~~~~~
+   |                                      ~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this function takes 1 argument but 2 arguments were supplied
   --> $DIR/args-instead-of-tuple-errors.rs:8:5
@@ -42,7 +42,7 @@ LL | fn int_bool(_: (i32, bool)) {
 help: remove the extra argument
    |
 LL |     int_bool(/* (i32, bool) */);
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |             ~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this enum variant takes 1 argument but 0 arguments were supplied
   --> $DIR/args-instead-of-tuple-errors.rs:11:28
@@ -58,7 +58,7 @@ LL |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: provide the argument
    |
 LL |     let _: Option<(i8,)> = Some(/* (i8,) */);
-   |                            ~~~~~~~~~~~~~~~~~
+   |                                ~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/args-instead-of-tuple-errors.rs:14:34
diff --git a/src/test/ui/suggestions/args-instead-of-tuple.stderr b/src/test/ui/suggestions/args-instead-of-tuple.stderr
index 2448a5149654..20f9e5259a4e 100644
--- a/src/test/ui/suggestions/args-instead-of-tuple.stderr
+++ b/src/test/ui/suggestions/args-instead-of-tuple.stderr
@@ -44,7 +44,7 @@ LL |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: provide the argument
    |
 LL |     let _: Option<()> = Some(());
-   |                         ~~~~~~~~
+   |                             ~~~~
 
 error[E0308]: mismatched types
   --> $DIR/args-instead-of-tuple.rs:14:34
diff --git a/src/test/ui/suggestions/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr b/src/test/ui/suggestions/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr
index c7d420e0aae8..bfd506c9f6e0 100644
--- a/src/test/ui/suggestions/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr
+++ b/src/test/ui/suggestions/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr
@@ -9,7 +9,7 @@ LL |     bar(foo);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `Future` is not implemented for `fn() -> impl Future<Output = ()> {foo}`
+   = help: the trait `Future` is not implemented for fn item `fn() -> impl Future<Output = ()> {foo}`
    = note: fn() -> impl Future<Output = ()> {foo} must be a future or must implement `IntoFuture` to be awaited
 note: required by a bound in `bar`
   --> $DIR/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:7:16
@@ -31,7 +31,7 @@ LL |     bar(async_closure);
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `Future` is not implemented for `[closure@$DIR/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:11:25: 11:33]`
+   = help: the trait `Future` is not implemented for closure `[closure@$DIR/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:11:25: 11:33]`
    = note: [closure@$DIR/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:11:25: 11:33] must be a future or must implement `IntoFuture` to be awaited
 note: required by a bound in `bar`
   --> $DIR/async-fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:7:16
diff --git a/src/test/ui/suggestions/copied-and-cloned.fixed b/src/test/ui/suggestions/copied-and-cloned.fixed
new file mode 100644
index 000000000000..f801403feec4
--- /dev/null
+++ b/src/test/ui/suggestions/copied-and-cloned.fixed
@@ -0,0 +1,23 @@
+// run-rustfix
+
+fn expect<T>(_: T) {}
+
+fn main() {
+    let x = Some(&());
+    expect::<Option<()>>(x.copied());
+    //~^ ERROR mismatched types
+    //~| HELP use `Option::copied` to copy the value inside the `Option`
+    let x = Ok(&());
+    expect::<Result<(), ()>>(x.copied());
+    //~^ ERROR mismatched types
+    //~| HELP use `Result::copied` to copy the value inside the `Result`
+    let s = String::new();
+    let x = Some(&s);
+    expect::<Option<String>>(x.cloned());
+    //~^ ERROR mismatched types
+    //~| HELP use `Option::cloned` to clone the value inside the `Option`
+    let x = Ok(&s);
+    expect::<Result<String, ()>>(x.cloned());
+    //~^ ERROR mismatched types
+    //~| HELP use `Result::cloned` to clone the value inside the `Result`
+}
diff --git a/src/test/ui/suggestions/copied-and-cloned.rs b/src/test/ui/suggestions/copied-and-cloned.rs
new file mode 100644
index 000000000000..640450b76552
--- /dev/null
+++ b/src/test/ui/suggestions/copied-and-cloned.rs
@@ -0,0 +1,23 @@
+// run-rustfix
+
+fn expect<T>(_: T) {}
+
+fn main() {
+    let x = Some(&());
+    expect::<Option<()>>(x);
+    //~^ ERROR mismatched types
+    //~| HELP use `Option::copied` to copy the value inside the `Option`
+    let x = Ok(&());
+    expect::<Result<(), ()>>(x);
+    //~^ ERROR mismatched types
+    //~| HELP use `Result::copied` to copy the value inside the `Result`
+    let s = String::new();
+    let x = Some(&s);
+    expect::<Option<String>>(x);
+    //~^ ERROR mismatched types
+    //~| HELP use `Option::cloned` to clone the value inside the `Option`
+    let x = Ok(&s);
+    expect::<Result<String, ()>>(x);
+    //~^ ERROR mismatched types
+    //~| HELP use `Result::cloned` to clone the value inside the `Result`
+}
diff --git a/src/test/ui/suggestions/copied-and-cloned.stderr b/src/test/ui/suggestions/copied-and-cloned.stderr
new file mode 100644
index 000000000000..a6336281b407
--- /dev/null
+++ b/src/test/ui/suggestions/copied-and-cloned.stderr
@@ -0,0 +1,83 @@
+error[E0308]: mismatched types
+  --> $DIR/copied-and-cloned.rs:7:26
+   |
+LL |     expect::<Option<()>>(x);
+   |     -------------------- ^ expected `()`, found `&()`
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected enum `Option<()>`
+              found enum `Option<&()>`
+note: function defined here
+  --> $DIR/copied-and-cloned.rs:3:4
+   |
+LL | fn expect<T>(_: T) {}
+   |    ^^^^^^    ----
+help: use `Option::copied` to copy the value inside the `Option`
+   |
+LL |     expect::<Option<()>>(x.copied());
+   |                           +++++++++
+
+error[E0308]: mismatched types
+  --> $DIR/copied-and-cloned.rs:11:30
+   |
+LL |     expect::<Result<(), ()>>(x);
+   |     ------------------------ ^ expected `()`, found `&()`
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected enum `Result<(), ()>`
+              found enum `Result<&(), _>`
+note: function defined here
+  --> $DIR/copied-and-cloned.rs:3:4
+   |
+LL | fn expect<T>(_: T) {}
+   |    ^^^^^^    ----
+help: use `Result::copied` to copy the value inside the `Result`
+   |
+LL |     expect::<Result<(), ()>>(x.copied());
+   |                               +++++++++
+
+error[E0308]: mismatched types
+  --> $DIR/copied-and-cloned.rs:16:30
+   |
+LL |     expect::<Option<String>>(x);
+   |     ------------------------ ^ expected struct `String`, found `&String`
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected enum `Option<String>`
+              found enum `Option<&String>`
+note: function defined here
+  --> $DIR/copied-and-cloned.rs:3:4
+   |
+LL | fn expect<T>(_: T) {}
+   |    ^^^^^^    ----
+help: use `Option::cloned` to clone the value inside the `Option`
+   |
+LL |     expect::<Option<String>>(x.cloned());
+   |                               +++++++++
+
+error[E0308]: mismatched types
+  --> $DIR/copied-and-cloned.rs:20:34
+   |
+LL |     expect::<Result<String, ()>>(x);
+   |     ---------------------------- ^ expected struct `String`, found `&String`
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected enum `Result<String, ()>`
+              found enum `Result<&String, _>`
+note: function defined here
+  --> $DIR/copied-and-cloned.rs:3:4
+   |
+LL | fn expect<T>(_: T) {}
+   |    ^^^^^^    ----
+help: use `Result::cloned` to clone the value inside the `Result`
+   |
+LL |     expect::<Result<String, ()>>(x.cloned());
+   |                                   +++++++++
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/deref-path-method.rs b/src/test/ui/suggestions/deref-path-method.rs
new file mode 100644
index 000000000000..0281cdb6b37c
--- /dev/null
+++ b/src/test/ui/suggestions/deref-path-method.rs
@@ -0,0 +1,6 @@
+fn main() {
+    let vec = Vec::new();
+    Vec::contains(&vec, &0);
+    //~^ ERROR no function or associated item named `contains` found for struct `Vec<_, _>` in the current scope
+    //~| HELP the function `contains` is implemented on `[_]`
+}
diff --git a/src/test/ui/suggestions/deref-path-method.stderr b/src/test/ui/suggestions/deref-path-method.stderr
new file mode 100644
index 000000000000..1cc37d61151c
--- /dev/null
+++ b/src/test/ui/suggestions/deref-path-method.stderr
@@ -0,0 +1,14 @@
+error[E0599]: no function or associated item named `contains` found for struct `Vec<_, _>` in the current scope
+  --> $DIR/deref-path-method.rs:3:10
+   |
+LL |     Vec::contains(&vec, &0);
+   |          ^^^^^^^^ function or associated item not found in `Vec<_, _>`
+   |
+help: the function `contains` is implemented on `[_]`
+   |
+LL |     <[_]>::contains(&vec, &0);
+   |     ~~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr b/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr
index e43a4e79bfe8..77cef485f30e 100644
--- a/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr
+++ b/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr
@@ -91,7 +91,7 @@ LL |   pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
    |                                             ------------------------------- the found opaque type
    |
    = note:   expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>`
-           found opaque type `impl Future`
+           found opaque type `impl Future<Output = {integer}>`
 help: you need to pin and box this expression
    |
 LL ~     Box::pin(async {
diff --git a/src/test/ui/suggestions/fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr b/src/test/ui/suggestions/fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr
index fb0a6f70bfb4..fe603b67575d 100644
--- a/src/test/ui/suggestions/fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr
+++ b/src/test/ui/suggestions/fn-ctor-passed-as-arg-where-it-should-have-been-called.stderr
@@ -5,7 +5,7 @@ LL | fn foo() -> impl T<O=()> { S }
    |    --- consider calling this function
 ...
 LL |     bar(foo);
-   |     --- ^^^ the trait `T` is not implemented for `fn() -> impl T<O = ()> {foo}`
+   |     --- ^^^ the trait `T` is not implemented for fn item `fn() -> impl T<O = ()> {foo}`
    |     |
    |     required by a bound introduced by this call
    |
@@ -25,7 +25,7 @@ error[E0277]: the trait bound `[closure@$DIR/fn-ctor-passed-as-arg-where-it-shou
 LL |     let closure = || S;
    |                   -- consider calling this closure
 LL |     bar(closure);
-   |     --- ^^^^^^^ the trait `T` is not implemented for `[closure@$DIR/fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:18:19: 18:21]`
+   |     --- ^^^^^^^ the trait `T` is not implemented for closure `[closure@$DIR/fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:18:19: 18:21]`
    |     |
    |     required by a bound introduced by this call
    |
diff --git a/src/test/ui/suggestions/fn-or-tuple-struct-without-args.stderr b/src/test/ui/suggestions/fn-or-tuple-struct-without-args.stderr
index 3c7b895e337e..f05dba1d4ca7 100644
--- a/src/test/ui/suggestions/fn-or-tuple-struct-without-args.stderr
+++ b/src/test/ui/suggestions/fn-or-tuple-struct-without-args.stderr
@@ -220,7 +220,7 @@ error[E0308]: mismatched types
   --> $DIR/fn-or-tuple-struct-without-args.rs:41:20
    |
 LL |     fn ban(&self) -> usize { 42 }
-   |     ---------------------- for<'r> fn(&'r X) -> usize {<X as T>::ban} defined here
+   |     ---------------------- for<'a> fn(&'a X) -> usize {<X as T>::ban} defined here
 ...
 LL |     let _: usize = X::ban;
    |            -----   ^^^^^^ expected `usize`, found fn item
@@ -228,7 +228,7 @@ LL |     let _: usize = X::ban;
    |            expected due to this
    |
    = note: expected type `usize`
-           found fn item `for<'r> fn(&'r X) -> usize {<X as T>::ban}`
+           found fn item `for<'a> fn(&'a X) -> usize {<X as T>::ban}`
 help: use parentheses to call this associated function
    |
 LL |     let _: usize = X::ban(/* &X */);
@@ -238,7 +238,7 @@ error[E0308]: mismatched types
   --> $DIR/fn-or-tuple-struct-without-args.rs:42:20
    |
 LL |     fn bal(&self) -> usize;
-   |     ----------------------- for<'r> fn(&'r X) -> usize {<X as T>::bal} defined here
+   |     ----------------------- for<'a> fn(&'a X) -> usize {<X as T>::bal} defined here
 ...
 LL |     let _: usize = X::bal;
    |            -----   ^^^^^^ expected `usize`, found fn item
@@ -246,7 +246,7 @@ LL |     let _: usize = X::bal;
    |            expected due to this
    |
    = note: expected type `usize`
-           found fn item `for<'r> fn(&'r X) -> usize {<X as T>::bal}`
+           found fn item `for<'a> fn(&'a X) -> usize {<X as T>::bal}`
 help: use parentheses to call this associated function
    |
 LL |     let _: usize = X::bal(/* &X */);
diff --git a/src/test/ui/suggestions/issue-101065.fixed b/src/test/ui/suggestions/issue-101065.fixed
new file mode 100644
index 000000000000..88c716cc86ce
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101065.fixed
@@ -0,0 +1,14 @@
+// check-fail
+// run-rustfix
+
+enum FakeResult<T> {
+    Ok(T)
+}
+
+fn main() {
+    let _x = if true {
+        FakeResult::Ok(FakeResult::Ok(()))
+    } else {
+        FakeResult::Ok(FakeResult::Ok(())) //~ERROR E0308
+    };
+}
diff --git a/src/test/ui/suggestions/issue-101065.rs b/src/test/ui/suggestions/issue-101065.rs
new file mode 100644
index 000000000000..2715f1027082
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101065.rs
@@ -0,0 +1,14 @@
+// check-fail
+// run-rustfix
+
+enum FakeResult<T> {
+    Ok(T)
+}
+
+fn main() {
+    let _x = if true {
+        FakeResult::Ok(FakeResult::Ok(()))
+    } else {
+        FakeResult::Ok(()) //~ERROR E0308
+    };
+}
diff --git a/src/test/ui/suggestions/issue-101065.stderr b/src/test/ui/suggestions/issue-101065.stderr
new file mode 100644
index 000000000000..6f7ecd24ca42
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101065.stderr
@@ -0,0 +1,23 @@
+error[E0308]: `if` and `else` have incompatible types
+  --> $DIR/issue-101065.rs:12:9
+   |
+LL |       let _x = if true {
+   |  ______________-
+LL | |         FakeResult::Ok(FakeResult::Ok(()))
+   | |         ---------------------------------- expected because of this
+LL | |     } else {
+LL | |         FakeResult::Ok(())
+   | |         ^^^^^^^^^^^^^^^^^^ expected enum `FakeResult`, found `()`
+LL | |     };
+   | |_____- `if` and `else` have incompatible types
+   |
+   = note: expected enum `FakeResult<FakeResult<()>>`
+              found enum `FakeResult<()>`
+help: try wrapping the expression in `FakeResult::Ok`
+   |
+LL |         FakeResult::Ok(FakeResult::Ok(()))
+   |         +++++++++++++++                  +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/issue-101421.rs b/src/test/ui/suggestions/issue-101421.rs
new file mode 100644
index 000000000000..b615997d1a9a
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101421.rs
@@ -0,0 +1,12 @@
+pub trait Ice {
+    fn f(&self, _: ());
+}
+
+impl Ice for () {
+    fn f(&self, _: ()) {}
+}
+
+fn main() {
+    ().f::<()>(());
+    //~^ ERROR this associated function takes 0 generic arguments but 1 generic argument was supplied
+}
diff --git a/src/test/ui/suggestions/issue-101421.stderr b/src/test/ui/suggestions/issue-101421.stderr
new file mode 100644
index 000000000000..f8e1efb88202
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101421.stderr
@@ -0,0 +1,17 @@
+error[E0107]: this associated function takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/issue-101421.rs:10:8
+   |
+LL |     ().f::<()>(());
+   |        ^------ help: remove these generics
+   |        |
+   |        expected 0 generic arguments
+   |
+note: associated function defined here, with 0 generic parameters
+  --> $DIR/issue-101421.rs:2:8
+   |
+LL |     fn f(&self, _: ());
+   |        ^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0107`.
diff --git a/src/test/ui/suggestions/issue-101465.rs b/src/test/ui/suggestions/issue-101465.rs
new file mode 100644
index 000000000000..8e42e2c22243
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101465.rs
@@ -0,0 +1,25 @@
+#![feature(trait_alias)]
+
+struct B;
+struct C;
+
+trait Tr {}
+
+impl Tr for B {}
+impl Tr for C {}
+
+trait Tr2<S> = Into<S>;
+
+fn foo2<T: Tr2<()>>() {}
+
+fn foo() -> impl Tr {
+    let x = foo2::<_>();
+
+    match true {
+        true => B,
+        false => C,
+        //~^ `match` arms have incompatible types
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/issue-101465.stderr b/src/test/ui/suggestions/issue-101465.stderr
new file mode 100644
index 000000000000..e2ca7771257d
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101465.stderr
@@ -0,0 +1,25 @@
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/issue-101465.rs:20:18
+   |
+LL | /     match true {
+LL | |         true => B,
+   | |                 - this is found to be of type `B`
+LL | |         false => C,
+   | |                  ^ expected struct `B`, found struct `C`
+LL | |
+LL | |     }
+   | |_____- `match` arms have incompatible types
+   |
+help: you could change the return type to be a boxed trait object
+   |
+LL | fn foo() -> Box<dyn Tr> {
+   |             ~~~~~~~   +
+help: if you change the return type to expect trait objects, box the returned expressions
+   |
+LL ~         true => Box::new(B),
+LL ~         false => Box::new(C),
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/issue-101623.rs b/src/test/ui/suggestions/issue-101623.rs
new file mode 100644
index 000000000000..d18a4a21f0a5
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101623.rs
@@ -0,0 +1,25 @@
+pub struct Stuff {
+    inner: *mut (),
+}
+
+pub struct Wrap<T>(T);
+
+fn fun<T>(t: T) -> Wrap<T> {
+    todo!()
+}
+
+pub trait Trait<'de> {
+    fn do_stuff(_: Wrap<&'de mut Self>);
+}
+
+impl<'a> Trait<'a> for () {
+    fn do_stuff(_: Wrap<&'a mut Self>) {}
+}
+
+fn fun2(t: &mut Stuff) -> () {
+    let Stuff { inner, .. } = t;
+    Trait::do_stuff({ fun(&mut *inner) });
+    //~^ ERROR the trait bound `*mut (): Trait<'_>` is not satisfied
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/issue-101623.stderr b/src/test/ui/suggestions/issue-101623.stderr
new file mode 100644
index 000000000000..361483cc08db
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101623.stderr
@@ -0,0 +1,14 @@
+error[E0277]: the trait bound `*mut (): Trait<'_>` is not satisfied
+  --> $DIR/issue-101623.rs:21:21
+   |
+LL |     Trait::do_stuff({ fun(&mut *inner) });
+   |     --------------- ^^----------------^^
+   |     |               |
+   |     |               the trait `Trait<'_>` is not implemented for `*mut ()`
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `Trait<'a>` is implemented for `()`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/suggestions/issue-101984.rs b/src/test/ui/suggestions/issue-101984.rs
new file mode 100644
index 000000000000..5f7ecb77e0ed
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101984.rs
@@ -0,0 +1,27 @@
+use std::marker::PhantomData;
+
+type Component = fn(&());
+
+struct Wrapper {
+    router: Router<(Component, Box<Self>)>,
+}
+
+struct Match<C>(PhantomData<C>);
+
+struct Router<T>(PhantomData<T>);
+
+impl<T> Router<T> {
+    pub fn at(&self) -> Result<Match<&T>, ()> {
+        todo!()
+    }
+}
+
+impl Wrapper {
+    fn at(&self, path: &str) -> Result<(Component, Box<Self>), ()> {
+        let (cmp, router) = self.router.at()?;
+        //~^ ERROR mismatched types
+        todo!()
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/issue-101984.stderr b/src/test/ui/suggestions/issue-101984.stderr
new file mode 100644
index 000000000000..81758a7007c2
--- /dev/null
+++ b/src/test/ui/suggestions/issue-101984.stderr
@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-101984.rs:21:13
+   |
+LL |         let (cmp, router) = self.router.at()?;
+   |             ^^^^^^^^^^^^^   ----------------- this expression has type `Match<&(for<'a> fn(&'a ()), Box<Wrapper>)>`
+   |             |
+   |             expected struct `Match`, found tuple
+   |
+   = note: expected struct `Match<&(for<'a> fn(&'a ()), Box<Wrapper>)>`
+               found tuple `(_, _)`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/issue-61963.stderr b/src/test/ui/suggestions/issue-61963.stderr
index c0d776e59ab8..a788cab6e4e8 100644
--- a/src/test/ui/suggestions/issue-61963.stderr
+++ b/src/test/ui/suggestions/issue-61963.stderr
@@ -13,9 +13,8 @@ LL | #![deny(bare_trait_objects)]
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     bar: Box<Bar>,
-LL +     bar: Box<dyn Bar>,
-   |
+LL |     bar: Box<dyn Bar>,
+   |              +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-61963.rs:18:1
@@ -27,9 +26,8 @@ LL | pub struct Foo {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub struct Foo {
-LL + dyn pub struct Foo {
-   |
+LL | dyn pub struct Foo {
+   | +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-61963.rs:28:14
@@ -41,9 +39,8 @@ LL |     bar: Box<Bar>,
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     bar: Box<Bar>,
-LL +     bar: Box<dyn Bar>,
-   |
+LL |     bar: Box<dyn Bar>,
+   |              +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-61963.rs:28:14
@@ -55,9 +52,8 @@ LL |     bar: Box<Bar>,
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL -     bar: Box<Bar>,
-LL +     bar: Box<dyn Bar>,
-   |
+LL |     bar: Box<dyn Bar>,
+   |              +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-61963.rs:18:1
@@ -69,9 +65,8 @@ LL | pub struct Foo {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub struct Foo {
-LL + dyn pub struct Foo {
-   |
+LL | dyn pub struct Foo {
+   | +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-61963.rs:18:1
@@ -83,9 +78,8 @@ LL | pub struct Foo {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub struct Foo {
-LL + dyn pub struct Foo {
-   |
+LL | dyn pub struct Foo {
+   | +++
 
 error: trait objects without an explicit `dyn` are deprecated
   --> $DIR/issue-61963.rs:18:1
@@ -97,9 +91,8 @@ LL | pub struct Foo {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - pub struct Foo {
-LL + dyn pub struct Foo {
-   |
+LL | dyn pub struct Foo {
+   | +++
 
 error: aborting due to 7 previous errors
 
diff --git a/src/test/ui/suggestions/issue-85347.rs b/src/test/ui/suggestions/issue-85347.rs
index f08e38689d6a..dd52b3150551 100644
--- a/src/test/ui/suggestions/issue-85347.rs
+++ b/src/test/ui/suggestions/issue-85347.rs
@@ -1,5 +1,3 @@
-#![allow(incomplete_features)]
-#![feature(generic_associated_types)]
 use std::ops::Deref;
 trait Foo {
     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
diff --git a/src/test/ui/suggestions/issue-85347.stderr b/src/test/ui/suggestions/issue-85347.stderr
index fccd2ef8df77..de853de27e40 100644
--- a/src/test/ui/suggestions/issue-85347.stderr
+++ b/src/test/ui/suggestions/issue-85347.stderr
@@ -1,11 +1,11 @@
 error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
-  --> $DIR/issue-85347.rs:5:42
+  --> $DIR/issue-85347.rs:3:42
    |
 LL |     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
    |                                          ^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-85347.rs:5:10
+  --> $DIR/issue-85347.rs:3:10
    |
 LL |     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
    |          ^^^ --
diff --git a/src/test/ui/suggestions/issue-89064.rs b/src/test/ui/suggestions/issue-89064.rs
new file mode 100644
index 000000000000..fa5fc899dc08
--- /dev/null
+++ b/src/test/ui/suggestions/issue-89064.rs
@@ -0,0 +1,35 @@
+use std::convert::TryInto;
+
+trait A<T> {
+    fn foo() {}
+}
+
+trait B<T, U> {
+    fn bar() {}
+}
+
+struct S;
+
+impl<T> A<T> for S {}
+impl<T, U> B<T, U> for S {}
+
+fn main() {
+    let _ = A::foo::<S>();
+    //~^ ERROR
+    //~| HELP remove these generics
+    //~| HELP consider moving this generic argument
+
+    let _ = B::bar::<S, S>();
+    //~^ ERROR
+    //~| HELP remove these generics
+    //~| HELP consider moving these generic arguments
+
+    let _ = A::<S>::foo::<S>();
+    //~^ ERROR
+    //~| HELP remove these generics
+
+    let _ = 42.into::<Option<_>>();
+    //~^ ERROR
+    //~| HELP remove these generics
+    //~| HELP consider moving this generic argument
+}
diff --git a/src/test/ui/suggestions/issue-89064.stderr b/src/test/ui/suggestions/issue-89064.stderr
new file mode 100644
index 000000000000..8b2a38816280
--- /dev/null
+++ b/src/test/ui/suggestions/issue-89064.stderr
@@ -0,0 +1,82 @@
+error[E0107]: this associated function takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/issue-89064.rs:17:16
+   |
+LL |     let _ = A::foo::<S>();
+   |                ^^^ expected 0 generic arguments
+   |
+note: associated function defined here, with 0 generic parameters
+  --> $DIR/issue-89064.rs:4:8
+   |
+LL |     fn foo() {}
+   |        ^^^
+help: consider moving this generic argument to the `A` trait, which takes up to 1 argument
+   |
+LL -     let _ = A::foo::<S>();
+LL +     let _ = A::<S>::foo();
+   |
+help: remove these generics
+   |
+LL -     let _ = A::foo::<S>();
+LL +     let _ = A::foo();
+   |
+
+error[E0107]: this associated function takes 0 generic arguments but 2 generic arguments were supplied
+  --> $DIR/issue-89064.rs:22:16
+   |
+LL |     let _ = B::bar::<S, S>();
+   |                ^^^ expected 0 generic arguments
+   |
+note: associated function defined here, with 0 generic parameters
+  --> $DIR/issue-89064.rs:8:8
+   |
+LL |     fn bar() {}
+   |        ^^^
+help: consider moving these generic arguments to the `B` trait, which takes up to 2 arguments
+   |
+LL -     let _ = B::bar::<S, S>();
+LL +     let _ = B::<S, S>::bar();
+   |
+help: remove these generics
+   |
+LL -     let _ = B::bar::<S, S>();
+LL +     let _ = B::bar();
+   |
+
+error[E0107]: this associated function takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/issue-89064.rs:27:21
+   |
+LL |     let _ = A::<S>::foo::<S>();
+   |                     ^^^----- help: remove these generics
+   |                     |
+   |                     expected 0 generic arguments
+   |
+note: associated function defined here, with 0 generic parameters
+  --> $DIR/issue-89064.rs:4:8
+   |
+LL |     fn foo() {}
+   |        ^^^
+
+error[E0107]: this associated function takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/issue-89064.rs:31:16
+   |
+LL |     let _ = 42.into::<Option<_>>();
+   |                ^^^^ expected 0 generic arguments
+   |
+note: associated function defined here, with 0 generic parameters
+  --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
+   |
+LL |     fn into(self) -> T;
+   |        ^^^^
+help: consider moving this generic argument to the `Into` trait, which takes up to 1 argument
+   |
+LL |     let _ = Into::<Option<_>>::into(42);
+   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+help: remove these generics
+   |
+LL -     let _ = 42.into::<Option<_>>();
+LL +     let _ = 42.into();
+   |
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0107`.
diff --git a/src/test/ui/suggestions/issue-97677.fixed b/src/test/ui/suggestions/issue-97677.fixed
index 73ca9f97b43a..1e7569fa4510 100644
--- a/src/test/ui/suggestions/issue-97677.fixed
+++ b/src/test/ui/suggestions/issue-97677.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
-fn add_ten<N: std::ops::Add<i32, Output=N>>(n: N) -> N {
+fn add_ten<N: std::ops::Add<i32, Output = N>>(n: N) -> N {
     n + 10
     //~^ ERROR cannot add `{integer}` to `N`
 }
diff --git a/src/test/ui/suggestions/issue-97677.stderr b/src/test/ui/suggestions/issue-97677.stderr
index 069b184ac636..575d79267f20 100644
--- a/src/test/ui/suggestions/issue-97677.stderr
+++ b/src/test/ui/suggestions/issue-97677.stderr
@@ -8,8 +8,8 @@ LL |     n + 10
    |
 help: consider restricting type parameter `N`
    |
-LL | fn add_ten<N: std::ops::Add<i32, Output=N>>(n: N) -> N {
-   |             ++++++++++++++++++++++++++++++
+LL | fn add_ten<N: std::ops::Add<i32, Output = N>>(n: N) -> N {
+   |             ++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
index 5dcbb86cbdf7..872263fd7311 100644
--- a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
+++ b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
@@ -22,8 +22,8 @@ LL | |     });
    | |______^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn func<T: Test + 'a>(foo: &Foo, t: T) {
-   |                 ++++
+LL | fn func<'a, T: Test + 'a>(foo: &Foo, t: T) {
+   |         +++         ++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
index bd5b3b5340ab..171f4b333db4 100644
--- a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
+++ b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
@@ -47,8 +47,10 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL |     G: Get<T> + 'a,
-   |               ++++
+LL ~ fn bar<'a, G, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
+LL | where
+LL ~     G: Get<T> + 'a,
+   |
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:52:5
@@ -74,8 +76,8 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn qux<'a, G: 'a + 'b, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
-   |                  ++++
+LL | fn qux<'b, 'a, G: 'a + 'b, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
+   |        +++           ++++
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:61:9
@@ -101,8 +103,8 @@ LL | |         }
    | |_________^
 help: consider adding an explicit lifetime bound...
    |
-LL |     fn qux<'b, G: Get<T> + 'b + 'c, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ {
-   |                               ++++
+LL |     fn qux<'c, 'b, G: Get<T> + 'b + 'c, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ {
+   |            +++                    ++++
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:73:5
@@ -130,8 +132,8 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn bat<'a, G: 'a + 'b, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
-   |                  ++++
+LL | fn bat<'b, 'a, G: 'a + 'b, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
+   |        +++           ++++
 
 error[E0621]: explicit lifetime required in the type of `dest`
   --> $DIR/missing-lifetimes-in-signature.rs:73:5
diff --git a/src/test/ui/suggestions/missing-bound-in-manual-copy-impl-2.stderr b/src/test/ui/suggestions/missing-bound-in-manual-copy-impl-2.stderr
index e0f405eedfa6..9e6f0d9ebbd2 100644
--- a/src/test/ui/suggestions/missing-bound-in-manual-copy-impl-2.stderr
+++ b/src/test/ui/suggestions/missing-bound-in-manual-copy-impl-2.stderr
@@ -1,11 +1,11 @@
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/missing-bound-in-manual-copy-impl-2.rs:16:9
+  --> $DIR/missing-bound-in-manual-copy-impl-2.rs:16:18
    |
 LL | struct Wrapper<T>(T);
    |                   - this field does not implement `Copy`
 ...
 LL | impl<S> Copy for Wrapper<OnlyCopyIfDisplay<S>> {}
-   |         ^^^^
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: the `Copy` impl for `OnlyCopyIfDisplay<S>` requires that `S: std::fmt::Display`
   --> $DIR/missing-bound-in-manual-copy-impl-2.rs:4:19
diff --git a/src/test/ui/suggestions/missing-bound-in-manual-copy-impl.stderr b/src/test/ui/suggestions/missing-bound-in-manual-copy-impl.stderr
index 218988511dbc..fe2d133c8aa7 100644
--- a/src/test/ui/suggestions/missing-bound-in-manual-copy-impl.stderr
+++ b/src/test/ui/suggestions/missing-bound-in-manual-copy-impl.stderr
@@ -1,11 +1,11 @@
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/missing-bound-in-manual-copy-impl.rs:6:9
+  --> $DIR/missing-bound-in-manual-copy-impl.rs:6:18
    |
 LL | struct Wrapper<T>(T);
    |                   - this field does not implement `Copy`
 LL |
 LL | impl<S> Copy for Wrapper<S> {}
-   |         ^^^^
+   |                  ^^^^^^^^^^
    |
 help: consider restricting type parameter `S`
    |
diff --git a/src/test/ui/suggestions/move-generic-to-trait-in-method-with-params.rs b/src/test/ui/suggestions/move-generic-to-trait-in-method-with-params.rs
new file mode 100644
index 000000000000..2f540060a349
--- /dev/null
+++ b/src/test/ui/suggestions/move-generic-to-trait-in-method-with-params.rs
@@ -0,0 +1,18 @@
+// Generalizes the suggestion introduced in #100838
+
+trait Foo<T> {
+    fn bar(&self, _: T);
+}
+
+impl Foo<i32> for i32 {
+    fn bar(&self, x: i32) {
+        println!("{}", self + x);
+    }
+}
+
+fn main() {
+    1.bar::<i32>(0);
+    //~^ ERROR this associated function takes 0 generic arguments but 1 generic argument was supplied
+    //~| HELP consider moving this generic argument to the `Foo` trait, which takes up to 1 argument
+    //~| HELP remove these generics
+}
diff --git a/src/test/ui/suggestions/move-generic-to-trait-in-method-with-params.stderr b/src/test/ui/suggestions/move-generic-to-trait-in-method-with-params.stderr
new file mode 100644
index 000000000000..9557220f6bb5
--- /dev/null
+++ b/src/test/ui/suggestions/move-generic-to-trait-in-method-with-params.stderr
@@ -0,0 +1,24 @@
+error[E0107]: this associated function takes 0 generic arguments but 1 generic argument was supplied
+  --> $DIR/move-generic-to-trait-in-method-with-params.rs:14:7
+   |
+LL |     1.bar::<i32>(0);
+   |       ^^^ expected 0 generic arguments
+   |
+note: associated function defined here, with 0 generic parameters
+  --> $DIR/move-generic-to-trait-in-method-with-params.rs:4:8
+   |
+LL |     fn bar(&self, _: T);
+   |        ^^^
+help: consider moving this generic argument to the `Foo` trait, which takes up to 1 argument
+   |
+LL |     Foo::<i32>::bar(1, 0);
+   |     ~~~~~~~~~~~~~~~~~~~~~
+help: remove these generics
+   |
+LL -     1.bar::<i32>(0);
+LL +     1.bar(0);
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0107`.
diff --git a/src/test/ui/suggestions/restrict-type-not-param.rs b/src/test/ui/suggestions/restrict-type-not-param.rs
new file mode 100644
index 000000000000..60f5ba45c268
--- /dev/null
+++ b/src/test/ui/suggestions/restrict-type-not-param.rs
@@ -0,0 +1,12 @@
+use std::ops::Add;
+
+struct Wrapper<T>(T);
+
+trait Foo {}
+
+fn qux<T>(a: Wrapper<T>, b: T) -> T {
+    a + b
+    //~^ ERROR cannot add `T` to `Wrapper<T>`
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/restrict-type-not-param.stderr b/src/test/ui/suggestions/restrict-type-not-param.stderr
new file mode 100644
index 000000000000..e7d9c5ecbe48
--- /dev/null
+++ b/src/test/ui/suggestions/restrict-type-not-param.stderr
@@ -0,0 +1,26 @@
+error[E0369]: cannot add `T` to `Wrapper<T>`
+  --> $DIR/restrict-type-not-param.rs:8:7
+   |
+LL |     a + b
+   |     - ^ - T
+   |     |
+   |     Wrapper<T>
+   |
+note: an implementation of `Add<_>` might be missing for `Wrapper<T>`
+  --> $DIR/restrict-type-not-param.rs:3:1
+   |
+LL | struct Wrapper<T>(T);
+   | ^^^^^^^^^^^^^^^^^ must implement `Add<_>`
+note: the following trait must be implemented
+  --> $SRC_DIR/core/src/ops/arith.rs:LL:COL
+   |
+LL | pub trait Add<Rhs = Self> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
+   |
+LL | fn qux<T>(a: Wrapper<T>, b: T) -> T where Wrapper<T>: Add<T, Output = T> {
+   |                                     ++++++++++++++++++++++++++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0369`.
diff --git a/src/test/ui/suggestions/return-closures.stderr b/src/test/ui/suggestions/return-closures.stderr
index e273793ea2c2..8b856d8de703 100644
--- a/src/test/ui/suggestions/return-closures.stderr
+++ b/src/test/ui/suggestions/return-closures.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/return-closures.rs:3:5
    |
 LL | fn foo() {
-   |          - help: try adding a return type: `-> impl for<'r> Fn(&'r i32) -> i32`
+   |          - help: try adding a return type: `-> impl for<'a> Fn(&'a i32) -> i32`
 LL |
 LL |     |x: &i32| 1i32
    |     ^^^^^^^^^^^^^^ expected `()`, found closure
diff --git a/src/test/ui/suggestions/suggest-blanket-impl-local-trait.rs b/src/test/ui/suggestions/suggest-blanket-impl-local-trait.rs
index 7cf536f7966e..14fef1b52489 100644
--- a/src/test/ui/suggestions/suggest-blanket-impl-local-trait.rs
+++ b/src/test/ui/suggestions/suggest-blanket-impl-local-trait.rs
@@ -1,5 +1,5 @@
 // Ensure that the compiler include the blanklet implementation suggestion
-// when inside a `impl` statment are used two local traits.
+// when inside a `impl` statement are used two local traits.
 //
 // edition:2021
 use std::fmt;
diff --git a/src/test/ui/suggestions/suggest-blanket-impl-local-trait.stderr b/src/test/ui/suggestions/suggest-blanket-impl-local-trait.stderr
index d739a8272f15..398caa98b84d 100644
--- a/src/test/ui/suggestions/suggest-blanket-impl-local-trait.stderr
+++ b/src/test/ui/suggestions/suggest-blanket-impl-local-trait.stderr
@@ -6,9 +6,8 @@ LL | impl LocalTraitTwo for LocalTraitOne {}
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl LocalTraitTwo for LocalTraitOne {}
-LL + impl LocalTraitTwo for dyn LocalTraitOne {}
-   |
+LL | impl LocalTraitTwo for dyn LocalTraitOne {}
+   |                        +++
 help: alternatively use a blanket implementation to implement `LocalTraitTwo` for all types that also implement `LocalTraitOne`
    |
 LL | impl<T: LocalTraitOne> LocalTraitTwo for T {}
@@ -22,9 +21,8 @@ LL | impl fmt::Display for LocalTraitOne {
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl fmt::Display for LocalTraitOne {
-LL + impl fmt::Display for dyn LocalTraitOne {
-   |
+LL | impl fmt::Display for dyn LocalTraitOne {
+   |                       +++
 
 error[E0782]: trait objects must include the `dyn` keyword
   --> $DIR/suggest-blanket-impl-local-trait.rs:26:23
@@ -34,9 +32,8 @@ LL | impl fmt::Display for LocalTraitTwo + Send {
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl fmt::Display for LocalTraitTwo + Send {
-LL + impl fmt::Display for dyn LocalTraitTwo + Send {
-   |
+LL | impl fmt::Display for dyn LocalTraitTwo + Send {
+   |                       +++
 
 error[E0782]: trait objects must include the `dyn` keyword
   --> $DIR/suggest-blanket-impl-local-trait.rs:34:24
@@ -46,9 +43,8 @@ LL | impl LocalTraitOne for fmt::Display {}
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl LocalTraitOne for fmt::Display {}
-LL + impl LocalTraitOne for dyn fmt::Display {}
-   |
+LL | impl LocalTraitOne for dyn fmt::Display {}
+   |                        +++
 help: alternatively use a blanket implementation to implement `LocalTraitOne` for all types that also implement `fmt::Display`
    |
 LL | impl<T: fmt::Display> LocalTraitOne for T {}
@@ -62,9 +58,8 @@ LL | impl LocalTraitOne for fmt::Display + Send {}
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl LocalTraitOne for fmt::Display + Send {}
-LL + impl LocalTraitOne for dyn fmt::Display + Send {}
-   |
+LL | impl LocalTraitOne for dyn fmt::Display + Send {}
+   |                        +++
 help: alternatively use a blanket implementation to implement `LocalTraitOne` for all types that also implement `fmt::Display + Send`
    |
 LL | impl<T: fmt::Display + Send> LocalTraitOne for T {}
@@ -78,9 +73,8 @@ LL | impl<E> GenericTrait<E> for LocalTraitOne {}
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl<E> GenericTrait<E> for LocalTraitOne {}
-LL + impl<E> GenericTrait<E> for dyn LocalTraitOne {}
-   |
+LL | impl<E> GenericTrait<E> for dyn LocalTraitOne {}
+   |                             +++
 help: alternatively use a blanket implementation to implement `GenericTrait<E>` for all types that also implement `LocalTraitOne`
    |
 LL | impl<E, T: LocalTraitOne> GenericTrait<E> for T {}
@@ -94,9 +88,8 @@ LL | impl<T, E> GenericTraitTwo<E> for GenericTrait<T> {}
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl<T, E> GenericTraitTwo<E> for GenericTrait<T> {}
-LL + impl<T, E> GenericTraitTwo<E> for dyn GenericTrait<T> {}
-   |
+LL | impl<T, E> GenericTraitTwo<E> for dyn GenericTrait<T> {}
+   |                                   +++
 help: alternatively use a blanket implementation to implement `GenericTraitTwo<E>` for all types that also implement `GenericTrait<T>`
    |
 LL | impl<T, E, U: GenericTrait<T>> GenericTraitTwo<E> for U {}
diff --git a/src/test/ui/suggestions/suggest-move-lifetimes.stderr b/src/test/ui/suggestions/suggest-move-lifetimes.stderr
index f52631caed17..b1a49447d460 100644
--- a/src/test/ui/suggestions/suggest-move-lifetimes.stderr
+++ b/src/test/ui/suggestions/suggest-move-lifetimes.stderr
@@ -1,22 +1,22 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/suggest-move-lifetimes.rs:1:13
    |
 LL | struct A<T, 'a> {
    |         ----^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, T>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/suggest-move-lifetimes.rs:5:13
    |
 LL | struct B<T, 'a, U> {
    |         ----^^---- help: reorder the parameters: lifetimes, then consts and types: `<'a, T, U>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/suggest-move-lifetimes.rs:10:16
    |
 LL | struct C<T, U, 'a> {
    |         -------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, T, U>`
 
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime parameters must be declared prior to type and const parameters
   --> $DIR/suggest-move-lifetimes.rs:15:16
    |
 LL | struct D<T, U, 'a, 'b, V, 'c> {
diff --git a/src/test/ui/suggestions/suggest-move-types.stderr b/src/test/ui/suggestions/suggest-move-types.stderr
index 1a6032db0010..b222e8142bab 100644
--- a/src/test/ui/suggestions/suggest-move-types.stderr
+++ b/src/test/ui/suggestions/suggest-move-types.stderr
@@ -121,7 +121,7 @@ LL | struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), C=()
    |                                                        ^^
    |
    = note: lifetime arguments must be provided before type arguments
-   = help: reorder the arguments: lifetimes, then types: `<'a, 'b, 'c, T, U, V>`
+   = help: reorder the arguments: lifetimes, then type and consts: `<'a, 'b, 'c, T, U, V>`
 
 error[E0747]: lifetime provided when a type was expected
   --> $DIR/suggest-move-types.rs:82:56
@@ -130,7 +130,7 @@ LL | struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), U, '
    |                                                        ^^
    |
    = note: lifetime arguments must be provided before type arguments
-   = help: reorder the arguments: lifetimes, then types: `<'a, 'b, 'c, T, U, V>`
+   = help: reorder the arguments: lifetimes, then type and consts: `<'a, 'b, 'c, T, U, V>`
 
 error: aborting due to 12 previous errors
 
diff --git a/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait-edition-2021.stderr b/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait-edition-2021.stderr
index fc880d6b86a7..87e716436209 100644
--- a/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait-edition-2021.stderr
+++ b/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait-edition-2021.stderr
@@ -39,9 +39,8 @@ LL | impl<'a, T> Struct<T> for Trait<'a, T> {}
    |
 help: add `dyn` keyword before this trait
    |
-LL - impl<'a, T> Struct<T> for Trait<'a, T> {}
-LL + impl<'a, T> Struct<T> for dyn Trait<'a, T> {}
-   |
+LL | impl<'a, T> Struct<T> for dyn Trait<'a, T> {}
+   |                           +++
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait.stderr b/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait.stderr
index f5143762da8e..f716e6c17e22 100644
--- a/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait.stderr
+++ b/src/test/ui/suggestions/suggest-swapping-self-ty-and-trait.stderr
@@ -42,9 +42,8 @@ LL | impl<'a, T> Struct<T> for Trait<'a, T> {}
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - impl<'a, T> Struct<T> for Trait<'a, T> {}
-LL + impl<'a, T> Struct<T> for dyn Trait<'a, T> {}
-   |
+LL | impl<'a, T> Struct<T> for dyn Trait<'a, T> {}
+   |                           +++
 
 error: aborting due to 3 previous errors; 1 warning emitted
 
diff --git a/src/test/ui/symbol-names/impl1.legacy.stderr b/src/test/ui/symbol-names/impl1.legacy.stderr
index b6012e41594b..3d438df92b85 100644
--- a/src/test/ui/symbol-names/impl1.legacy.stderr
+++ b/src/test/ui/symbol-names/impl1.legacy.stderr
@@ -64,7 +64,7 @@ error: demangling-alt(<[&dyn impl1::Foo+Assoc = extern "C" fn(&u8, ::.)+impl1::A
 LL |             #[rustc_symbol_name]
    |             ^^^^^^^^^^^^^^^^^^^^
 
-error: def-path(<[&dyn Foo<Assoc = for<'r> extern "C" fn(&'r u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
+error: def-path(<[&dyn Foo<Assoc = for<'a> extern "C" fn(&'a u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
   --> $DIR/impl1.rs:69:13
    |
 LL |             #[rustc_def_path]
diff --git a/src/test/ui/symbol-names/impl1.rs b/src/test/ui/symbol-names/impl1.rs
index 86f0a8b0bef4..629c2f33ddcc 100644
--- a/src/test/ui/symbol-names/impl1.rs
+++ b/src/test/ui/symbol-names/impl1.rs
@@ -67,8 +67,8 @@ fn main() {
                 //[v0]~| ERROR demangling(<[&dyn
                 //[v0]~| ERROR demangling-alt(<[&dyn impl1::Foo<Assoc = for<'a> extern "C" fn(&'a u8, ...)> + impl1::AutoTrait; 3] as impl1::main::{closure#1}::Bar>::method)
             #[rustc_def_path]
-            //[legacy]~^ ERROR def-path(<[&dyn Foo<Assoc = for<'r> extern "C" fn(&'r u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
-               //[v0]~^^ ERROR def-path(<[&dyn Foo<Assoc = for<'r> extern "C" fn(&'r u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
+            //[legacy]~^ ERROR def-path(<[&dyn Foo<Assoc = for<'a> extern "C" fn(&'a u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
+               //[v0]~^^ ERROR def-path(<[&dyn Foo<Assoc = for<'a> extern "C" fn(&'a u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
             fn method(&self) {}
         }
     };
diff --git a/src/test/ui/symbol-names/impl1.v0.stderr b/src/test/ui/symbol-names/impl1.v0.stderr
index 48f7473b6a0d..33caad71f52f 100644
--- a/src/test/ui/symbol-names/impl1.v0.stderr
+++ b/src/test/ui/symbol-names/impl1.v0.stderr
@@ -64,7 +64,7 @@ error: demangling-alt(<[&dyn impl1::Foo<Assoc = for<'a> extern "C" fn(&'a u8, ..
 LL |             #[rustc_symbol_name]
    |             ^^^^^^^^^^^^^^^^^^^^
 
-error: def-path(<[&dyn Foo<Assoc = for<'r> extern "C" fn(&'r u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
+error: def-path(<[&dyn Foo<Assoc = for<'a> extern "C" fn(&'a u8, ...)> + AutoTrait; 3] as main::{closure#1}::Bar>::method)
   --> $DIR/impl1.rs:69:13
    |
 LL |             #[rustc_def_path]
diff --git a/src/test/ui/test-attrs/test-panic-while-printing.rs b/src/test/ui/test-attrs/test-panic-while-printing.rs
index 01e460da5ab5..033c8beb475d 100644
--- a/src/test/ui/test-attrs/test-panic-while-printing.rs
+++ b/src/test/ui/test-attrs/test-panic-while-printing.rs
@@ -1,7 +1,6 @@
 // compile-flags:--test
 // run-pass
 // needs-unwind
-// ignore-emscripten no subprocess support
 
 use std::fmt;
 use std::fmt::{Display, Formatter};
diff --git a/src/test/ui/test-attrs/test-should-fail-good-message.rs b/src/test/ui/test-attrs/test-should-fail-good-message.rs
index 3260b6938f07..83519c4524a6 100644
--- a/src/test/ui/test-attrs/test-should-fail-good-message.rs
+++ b/src/test/ui/test-attrs/test-should-fail-good-message.rs
@@ -1,6 +1,5 @@
 // run-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 // compile-flags: --test
 #[test]
 #[should_panic(expected = "foo")]
diff --git a/src/test/ui/thir-tree.stdout b/src/test/ui/thir-tree.stdout
index 960b7f7f4dde..7fb90581f8a8 100644
--- a/src/test/ui/thir-tree.stdout
+++ b/src/test/ui/thir-tree.stdout
@@ -33,7 +33,9 @@ Thir {
                 region_scope: Node(2),
                 lint_level: Explicit(
                     HirId {
-                        owner: DefId(0:3 ~ thir_tree[8f1d]::main),
+                        owner: OwnerId {
+                            def_id: DefId(0:3 ~ thir_tree[8f1d]::main),
+                        },
                         local_id: 2,
                     },
                 ),
@@ -54,5 +56,6 @@ Thir {
         },
     ],
     stmts: [],
+    params: [],
 }
 
diff --git a/src/test/ui/traits/associated_type_bound/check-trait-object-bounds-2.stderr b/src/test/ui/traits/associated_type_bound/check-trait-object-bounds-2.stderr
index 4084f69a6f04..10e82c54e0f2 100644
--- a/src/test/ui/traits/associated_type_bound/check-trait-object-bounds-2.stderr
+++ b/src/test/ui/traits/associated_type_bound/check-trait-object-bounds-2.stderr
@@ -4,7 +4,7 @@ error[E0277]: expected a `FnOnce<(&i32,)>` closure, found `i32`
 LL |     f::<dyn for<'x> X<'x, F = i32>>();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an `FnOnce<(&i32,)>` closure, found `i32`
    |
-   = help: the trait `for<'r> FnOnce<(&'r i32,)>` is not implemented for `i32`
+   = help: the trait `for<'a> FnOnce<(&'a i32,)>` is not implemented for `i32`
 note: required by a bound in `f`
   --> $DIR/check-trait-object-bounds-2.rs:8:9
    |
diff --git a/src/test/ui/traits/bound/not-on-bare-trait.stderr b/src/test/ui/traits/bound/not-on-bare-trait.stderr
index 8a92dd11872c..1c52629daa48 100644
--- a/src/test/ui/traits/bound/not-on-bare-trait.stderr
+++ b/src/test/ui/traits/bound/not-on-bare-trait.stderr
@@ -9,9 +9,8 @@ LL | fn foo(_x: Foo + Send) {
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
 help: use `dyn`
    |
-LL - fn foo(_x: Foo + Send) {
-LL + fn foo(_x: dyn Foo + Send) {
-   |
+LL | fn foo(_x: dyn Foo + Send) {
+   |            +++
 
 error[E0277]: the size for values of type `(dyn Foo + Send + 'static)` cannot be known at compilation time
   --> $DIR/not-on-bare-trait.rs:7:8
diff --git a/src/test/ui/traits/copy-impl-cannot-normalize.stderr b/src/test/ui/traits/copy-impl-cannot-normalize.stderr
index afdad160919f..68b95b42b346 100644
--- a/src/test/ui/traits/copy-impl-cannot-normalize.stderr
+++ b/src/test/ui/traits/copy-impl-cannot-normalize.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `T: TraitFoo` is not satisfied
-  --> $DIR/copy-impl-cannot-normalize.rs:22:1
+  --> $DIR/copy-impl-cannot-normalize.rs:22:18
    |
 LL | impl<T> Copy for Foo<T> {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `TraitFoo` is not implemented for `T`
+   |                  ^^^^^^ the trait `TraitFoo` is not implemented for `T`
    |
 help: consider restricting type parameter `T`
    |
diff --git a/src/test/ui/traits/negative-impls/explicitly-unimplemented-error-message.rs b/src/test/ui/traits/negative-impls/explicitly-unimplemented-error-message.rs
index 1314f9cb0932..17ddaa312f7c 100644
--- a/src/test/ui/traits/negative-impls/explicitly-unimplemented-error-message.rs
+++ b/src/test/ui/traits/negative-impls/explicitly-unimplemented-error-message.rs
@@ -1,5 +1,5 @@
 // This tests issue #79683: note in the error message that the trait is
-// explicitely unimplemented instead of suggesting to implement it.
+// explicitly unimplemented instead of suggesting to implement it.
 
 #![feature(negative_impls)]
 
diff --git a/src/test/ui/traits/resolution-in-overloaded-op.stderr b/src/test/ui/traits/resolution-in-overloaded-op.stderr
index 34fae64e4d20..fe5e1d6d2854 100644
--- a/src/test/ui/traits/resolution-in-overloaded-op.stderr
+++ b/src/test/ui/traits/resolution-in-overloaded-op.stderr
@@ -8,8 +8,8 @@ LL |     a * b
    |
 help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
-LL | fn foo<T: MyMul<f64, f64>>(a: &T, b: f64) -> f64 where &T: Mul<f64> {
-   |                                                  ++++++++++++++++++
+LL | fn foo<T: MyMul<f64, f64>>(a: &T, b: f64) -> f64 where &T: Mul<f64, Output = f64> {
+   |                                                  ++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/abstraction/abstracted_assume.rs b/src/test/ui/transmutability/abstraction/abstracted_assume.rs
index 2abbbf3c158d..0225c4230dc4 100644
--- a/src/test/ui/transmutability/abstraction/abstracted_assume.rs
+++ b/src/test/ui/transmutability/abstraction/abstracted_assume.rs
@@ -3,6 +3,7 @@
 //! provided indirectly through an abstraction.
 
 #![crate_type = "lib"]
+#![feature(adt_const_params)]
 #![feature(transmutability)]
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
@@ -13,19 +14,13 @@ mod assert {
         Src,
         Dst,
         Context,
-        const ASSUME_ALIGNMENT: bool,
-        const ASSUME_LIFETIMES: bool,
-        const ASSUME_VALIDITY: bool,
-        const ASSUME_VISIBILITY: bool,
+        const ASSUME: std::mem::Assume,
     >()
     where
         Dst: BikeshedIntrinsicFrom<
             Src,
             Context,
-            ASSUME_ALIGNMENT,
-            ASSUME_LIFETIMES,
-            ASSUME_VALIDITY,
-            ASSUME_VISIBILITY,
+            ASSUME,
         >,
     {}
 }
@@ -35,7 +30,7 @@ fn direct() {
     #[repr(C)] struct Src;
     #[repr(C)] struct Dst;
 
-    assert::is_transmutable::<Src, Dst, Context, false, false, false, false>();
+    assert::is_transmutable::<Src, Dst, Context, { std::mem::Assume::NOTHING }>();
 }
 
 fn via_const() {
@@ -45,7 +40,7 @@ fn via_const() {
 
     const FALSE: bool = false;
 
-    assert::is_transmutable::<Src, Dst, Context, FALSE, FALSE, FALSE, FALSE>();
+    assert::is_transmutable::<Src, Dst, Context, { std::mem::Assume::NOTHING }>();
 }
 
 fn via_associated_const() {
@@ -65,9 +60,13 @@ fn via_associated_const() {
         Src,
         Dst,
         Context,
-        {Ty::FALSE},
-        {Ty::FALSE},
-        {Ty::FALSE},
-        {Ty::FALSE}
+        {
+            std::mem::Assume {
+                alignment: {Ty::FALSE},
+                lifetimes: {Ty::FALSE},
+                safety: {Ty::FALSE},
+                validity: {Ty::FALSE},
+            }
+        }
     >();
 }
diff --git a/src/test/ui/transmutability/abstraction/const_generic_fn.rs b/src/test/ui/transmutability/abstraction/const_generic_fn.rs
index 94c38bb28f7e..e693a09570f3 100644
--- a/src/test/ui/transmutability/abstraction/const_generic_fn.rs
+++ b/src/test/ui/transmutability/abstraction/const_generic_fn.rs
@@ -6,13 +6,13 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn array_like<T, E, const N: usize>()
     where
-        T: BikeshedIntrinsicFrom<[E; N], Context, false, false, false, true>,
-        [E; N]: BikeshedIntrinsicFrom<T, Context, false, false, false, true>
+        T: BikeshedIntrinsicFrom<[E; N], Context, { Assume::SAFETY }>,
+        [E; N]: BikeshedIntrinsicFrom<T, Context, { Assume::SAFETY }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/arrays/should_have_correct_length.rs b/src/test/ui/transmutability/arrays/should_have_correct_length.rs
index bfe6d830a1be..353797d0c4bb 100644
--- a/src/test/ui/transmutability/arrays/should_have_correct_length.rs
+++ b/src/test/ui/transmutability/arrays/should_have_correct_length.rs
@@ -6,12 +6,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/arrays/should_inherit_alignment.rs b/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
index fcb1765ea6bb..b00e5c7e4008 100644
--- a/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
+++ b/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
@@ -6,12 +6,17 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
index 8e69527c1862..853bd9cbc0fb 100644
--- a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
@@ -5,12 +5,17 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
index eae0c947d425..96a2fdc54dbb 100644
--- a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
@@ -1,98 +1,134 @@
 error[E0277]: `[String; 0]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:21:52
+  --> $DIR/should_require_well_defined_layout.rs:26:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `[String; 0]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<[String; 0], assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<[String; 0], assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `[String; 0]` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:22:47
+  --> $DIR/should_require_well_defined_layout.rs:27:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `[String; 0]` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `[String; 0]`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `[String; 0]`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `[String; 1]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:27:52
+  --> $DIR/should_require_well_defined_layout.rs:32:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `[String; 1]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<[String; 1], assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<[String; 1], assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `[String; 1]` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:28:47
+  --> $DIR/should_require_well_defined_layout.rs:33:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `[String; 1]` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `[String; 1]`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `[String; 1]`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `[String; 2]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:33:52
+  --> $DIR/should_require_well_defined_layout.rs:38:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `[String; 2]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<[String; 2], assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<[String; 2], assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `[String; 2]` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:34:47
+  --> $DIR/should_require_well_defined_layout.rs:39:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `[String; 2]` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `[String; 2]`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `[String; 2]`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs
index 18e02b0d2b90..940f070e7e36 100644
--- a/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs
+++ b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs
@@ -5,11 +5,18 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr
index fa2e3b89b079..4da5fcea3374 100644
--- a/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr
+++ b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr
@@ -1,322 +1,462 @@
 error[E0277]: `Zst` cannot be safely transmuted into `V0i8` in the defining scope of `n8::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:41:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:48:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `Zst` cannot be safely transmuted into `V0i8` in the defining scope of `n8::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, true, true, true, true>` is not implemented for `V0i8`
+   = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0i8`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0i8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:43:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:50:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0i8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0i8, n8::Context, true, true, true, true>` is not implemented for `u16`
+   = help: the trait `BikeshedIntrinsicFrom<V0i8, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u16`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `Zst` cannot be safely transmuted into `V0u8` in the defining scope of `n8::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:49:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:56:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `Zst` cannot be safely transmuted into `V0u8` in the defining scope of `n8::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, true, true, true, true>` is not implemented for `V0u8`
+   = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0u8`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0u8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:51:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:58:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0u8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0u8, n8::Context, true, true, true, true>` is not implemented for `u16`
+   = help: the trait `BikeshedIntrinsicFrom<V0u8, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u16`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `V0i16` in the defining scope of `n16::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:65:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:72:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u8` cannot be safely transmuted into `V0i16` in the defining scope of `n16::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, true, true, true, true>` is not implemented for `V0i16`
+   = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0i16`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0i16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:67:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:74:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0i16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0i16, n16::Context, true, true, true, true>` is not implemented for `u32`
+   = help: the trait `BikeshedIntrinsicFrom<V0i16, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `V0u16` in the defining scope of `n16::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:73:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:80:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u8` cannot be safely transmuted into `V0u16` in the defining scope of `n16::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, true, true, true, true>` is not implemented for `V0u16`
+   = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0u16`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0u16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:75:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:82:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0u16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0u16, n16::Context, true, true, true, true>` is not implemented for `u32`
+   = help: the trait `BikeshedIntrinsicFrom<V0u16, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `V0i32` in the defining scope of `n32::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:89:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:96:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u16` cannot be safely transmuted into `V0i32` in the defining scope of `n32::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, true, true, true, true>` is not implemented for `V0i32`
+   = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0i32`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0i32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:91:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:98:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0i32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0i32, n32::Context, true, true, true, true>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<V0i32, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `V0u32` in the defining scope of `n32::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:97:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:104:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u16` cannot be safely transmuted into `V0u32` in the defining scope of `n32::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, true, true, true, true>` is not implemented for `V0u32`
+   = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0u32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:99:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:106:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0u32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0u32, n32::Context, true, true, true, true>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<V0u32, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `V0i64` in the defining scope of `n64::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:113:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:120:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u32` cannot be safely transmuted into `V0i64` in the defining scope of `n64::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, true, true, true, true>` is not implemented for `V0i64`
+   = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0i64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:115:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:122:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0i64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0i64, n64::Context, true, true, true, true>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<V0i64, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `V0u64` in the defining scope of `n64::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:121:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:128:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u32` cannot be safely transmuted into `V0u64` in the defining scope of `n64::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, true, true, true, true>` is not implemented for `V0u64`
+   = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0u64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:123:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:130:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0u64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0u64, n64::Context, true, true, true, true>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<V0u64, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `V0isize` in the defining scope of `nsize::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:137:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:144:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u8` cannot be safely transmuted into `V0isize` in the defining scope of `nsize::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, true, true, true, true>` is not implemented for `V0isize`
+   = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0isize`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0isize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:139:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:146:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0isize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0isize, nsize::Context, true, true, true, true>` is not implemented for `[usize; 2]`
+   = help: the trait `BikeshedIntrinsicFrom<V0isize, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `[usize; 2]`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `V0usize` in the defining scope of `nsize::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:145:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:152:44
    |
 LL |         assert::is_transmutable::<Smaller, Current, Context>();
    |                                            ^^^^^^^ `u8` cannot be safely transmuted into `V0usize` in the defining scope of `nsize::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, true, true, true, true>` is not implemented for `V0usize`
+   = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `V0usize`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error[E0277]: `V0usize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
-  --> $DIR/primitive_reprs_should_have_correct_length.rs:147:44
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:154:44
    |
 LL |         assert::is_transmutable::<Current, Larger, Context>();
    |                                            ^^^^^^ `V0usize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<V0usize, nsize::Context, true, true, true, true>` is not implemented for `[usize; 2]`
+   = help: the trait `BikeshedIntrinsicFrom<V0usize, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `[usize; 2]`
 note: required by a bound in `is_transmutable`
   --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to 20 previous errors
 
diff --git a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
index 978a12648f03..102111ae291c 100644
--- a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
+++ b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr
index 3273e87c89ff..510b8c56e5ab 100644
--- a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr
+++ b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr
@@ -1,98 +1,140 @@
 error[E0277]: `void::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:21:52
+  --> $DIR/should_require_well_defined_layout.rs:28:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `void::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<void::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<void::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:14:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `void::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:22:47
+  --> $DIR/should_require_well_defined_layout.rs:29:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `void::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `void::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `void::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:14:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `singleton::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:27:52
+  --> $DIR/should_require_well_defined_layout.rs:34:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `singleton::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<singleton::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<singleton::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:14:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `singleton::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:28:47
+  --> $DIR/should_require_well_defined_layout.rs:35:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `singleton::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `singleton::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `singleton::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:14:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `duplex::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:33:52
+  --> $DIR/should_require_well_defined_layout.rs:40:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `duplex::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<duplex::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<duplex::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:14:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `duplex::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:34:47
+  --> $DIR/should_require_well_defined_layout.rs:41:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `duplex::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `duplex::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `duplex::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:14:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/transmutability/enums/should_order_correctly.rs b/src/test/ui/transmutability/enums/should_order_correctly.rs
index 6558d2658ee4..b753cf0e62d5 100644
--- a/src/test/ui/transmutability/enums/should_order_correctly.rs
+++ b/src/test/ui/transmutability/enums/should_order_correctly.rs
@@ -7,12 +7,17 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/should_pad_variants.rs b/src/test/ui/transmutability/enums/should_pad_variants.rs
index 466b6c8a15b5..c077c52a36ac 100644
--- a/src/test/ui/transmutability/enums/should_pad_variants.rs
+++ b/src/test/ui/transmutability/enums/should_pad_variants.rs
@@ -6,11 +6,16 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/should_pad_variants.stderr b/src/test/ui/transmutability/enums/should_pad_variants.stderr
index 429f7211d17a..a823503d594e 100644
--- a/src/test/ui/transmutability/enums/should_pad_variants.stderr
+++ b/src/test/ui/transmutability/enums/should_pad_variants.stderr
@@ -1,18 +1,24 @@
 error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
-  --> $DIR/should_pad_variants.rs:39:36
+  --> $DIR/should_pad_variants.rs:44:36
    |
 LL |     assert::is_transmutable::<Src, Dst, Context>();
    |                                    ^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, true, true, true, true>` is not implemented for `Dst`
+   = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `Dst`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_pad_variants.rs:13:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/enums/should_respect_endianness.rs b/src/test/ui/transmutability/enums/should_respect_endianness.rs
index 67a3c4e94ba8..19ff69005003 100644
--- a/src/test/ui/transmutability/enums/should_respect_endianness.rs
+++ b/src/test/ui/transmutability/enums/should_respect_endianness.rs
@@ -7,12 +7,17 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/should_respect_endianness.stderr b/src/test/ui/transmutability/enums/should_respect_endianness.stderr
index 78023cb378ac..fcb70813bd96 100644
--- a/src/test/ui/transmutability/enums/should_respect_endianness.stderr
+++ b/src/test/ui/transmutability/enums/should_respect_endianness.stderr
@@ -1,18 +1,24 @@
 error[E0277]: `Src` cannot be safely transmuted into `Unexpected` in the defining scope of `assert::Context`.
-  --> $DIR/should_respect_endianness.rs:32:36
+  --> $DIR/should_respect_endianness.rs:37:36
    |
 LL |     assert::is_transmutable::<Src, Unexpected>();
    |                                    ^^^^^^^^^^ `Src` cannot be safely transmuted into `Unexpected` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, assert::Context, true, true, true, true>` is not implemented for `Unexpected`
+   = help: the trait `BikeshedIntrinsicFrom<Src, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `Unexpected`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_respect_endianness.rs:15:14
    |
-LL |     pub fn is_transmutable<Src, Dst>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
index e13462d390b0..b3a1e13b85be 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
@@ -10,7 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
index dc51e2a8f4d2..092b205b7702 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
@@ -10,7 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
index 86fc8bd6b285..ebe34e13432b 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
@@ -10,7 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
index bd36748e7901..52aa4bb31016 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
@@ -2,11 +2,13 @@
 //! provided.
 
 #![crate_type = "lib"]
+#![feature(adt_const_params)]
+#![feature(generic_const_exprs)]
 #![feature(transmutability)]
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<
         Src,
@@ -14,19 +16,30 @@ mod assert {
         Context,
         const ASSUME_ALIGNMENT: bool,
         const ASSUME_LIFETIMES: bool,
+        const ASSUME_SAFETY: bool,
         const ASSUME_VALIDITY: bool,
-        const ASSUME_VISIBILITY: bool,
     >()
     where
         Dst: BikeshedIntrinsicFrom<
             Src,
             Context,
-            ASSUME_ALIGNMENT,
-            ASSUME_LIFETIMES,
-            ASSUME_VALIDITY,
-            ASSUME_VISIBILITY,
+            { from_options(ASSUME_ALIGNMENT, ASSUME_LIFETIMES, ASSUME_SAFETY, ASSUME_VALIDITY) }
         >,
     {}
+
+    const fn from_options(
+        alignment: bool,
+        lifetimes: bool,
+        safety: bool,
+        validity: bool,
+    ) -> Assume {
+        Assume {
+            alignment,
+            lifetimes,
+            safety,
+            validity,
+        }
+    }
 }
 
 fn test() {
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
index e1464e02352c..c6d93876cfaf 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
@@ -1,23 +1,23 @@
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:36:51
+  --> $DIR/wrong-type-assume.rs:49:51
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, {0u8}, false, false, false>();
    |                                                   ^^^ expected `bool`, found `u8`
 
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:37:58
+  --> $DIR/wrong-type-assume.rs:50:58
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, false, {0u8}, false, false>();
    |                                                          ^^^ expected `bool`, found `u8`
 
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:38:65
+  --> $DIR/wrong-type-assume.rs:51:65
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, false, false, {0u8}, false>();
    |                                                                 ^^^ expected `bool`, found `u8`
 
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:39:72
+  --> $DIR/wrong-type-assume.rs:52:72
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, false, false, false, {0u8}>();
    |                                                                        ^^^ expected `bool`, found `u8`
diff --git a/src/test/ui/transmutability/primitives/bool.rs b/src/test/ui/transmutability/primitives/bool.rs
index 4f79bc253370..eebb74fff471 100644
--- a/src/test/ui/transmutability/primitives/bool.rs
+++ b/src/test/ui/transmutability/primitives/bool.rs
@@ -4,17 +4,17 @@
 #![allow(incomplete_features)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
     {}
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/primitives/bool.stderr b/src/test/ui/transmutability/primitives/bool.stderr
index dc740251c871..214b5e150edd 100644
--- a/src/test/ui/transmutability/primitives/bool.stderr
+++ b/src/test/ui/transmutability/primitives/bool.stderr
@@ -4,15 +4,15 @@ error[E0277]: `u8` cannot be safely transmuted into `bool` in the defining scope
 LL |     assert::is_transmutable::<u8, bool>();
    |                                   ^^^^ `u8` cannot be safely transmuted into `bool` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, true>` is not implemented for `bool`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` is not implemented for `bool`
 note: required by a bound in `is_transmutable`
   --> $DIR/bool.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/primitives/numbers.rs b/src/test/ui/transmutability/primitives/numbers.rs
index a5f79065d8aa..0df43d2045f7 100644
--- a/src/test/ui/transmutability/primitives/numbers.rs
+++ b/src/test/ui/transmutability/primitives/numbers.rs
@@ -9,7 +9,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
diff --git a/src/test/ui/transmutability/primitives/numbers.stderr b/src/test/ui/transmutability/primitives/numbers.stderr
index 9b802a444e86..7cb7ca8e6db5 100644
--- a/src/test/ui/transmutability/primitives/numbers.stderr
+++ b/src/test/ui/transmutability/primitives/numbers.stderr
@@ -4,15 +4,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i16` in the defining scope
 LL |     assert::is_transmutable::<   i8,   i16>();
    |                                        ^^^ `i8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i16`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i16`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:63:40
@@ -20,15 +20,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u16` in the defining scope
 LL |     assert::is_transmutable::<   i8,   u16>();
    |                                        ^^^ `i8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u16`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u16`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:64:40
@@ -36,15 +36,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i32` in the defining scope
 LL |     assert::is_transmutable::<   i8,   i32>();
    |                                        ^^^ `i8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i32`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:65:40
@@ -52,15 +52,15 @@ error[E0277]: `i8` cannot be safely transmuted into `f32` in the defining scope
 LL |     assert::is_transmutable::<   i8,   f32>();
    |                                        ^^^ `i8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `f32`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:66:40
@@ -68,15 +68,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u32` in the defining scope
 LL |     assert::is_transmutable::<   i8,   u32>();
    |                                        ^^^ `i8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u32`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:67:40
@@ -84,15 +84,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<   i8,   u64>();
    |                                        ^^^ `i8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:68:40
@@ -100,15 +100,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<   i8,   i64>();
    |                                        ^^^ `i8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:69:40
@@ -116,15 +116,15 @@ error[E0277]: `i8` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<   i8,   f64>();
    |                                        ^^^ `i8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:70:39
@@ -132,15 +132,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u128` in the defining scope
 LL |     assert::is_transmutable::<   i8,  u128>();
    |                                       ^^^^ `i8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:71:39
@@ -148,15 +148,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i128` in the defining scope
 LL |     assert::is_transmutable::<   i8,  i128>();
    |                                       ^^^^ `i8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:73:40
@@ -164,15 +164,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i16` in the defining scope
 LL |     assert::is_transmutable::<   u8,   i16>();
    |                                        ^^^ `u8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i16`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i16`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:74:40
@@ -180,15 +180,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u16` in the defining scope
 LL |     assert::is_transmutable::<   u8,   u16>();
    |                                        ^^^ `u8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u16`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u16`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:75:40
@@ -196,15 +196,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i32` in the defining scope
 LL |     assert::is_transmutable::<   u8,   i32>();
    |                                        ^^^ `u8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i32`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:76:40
@@ -212,15 +212,15 @@ error[E0277]: `u8` cannot be safely transmuted into `f32` in the defining scope
 LL |     assert::is_transmutable::<   u8,   f32>();
    |                                        ^^^ `u8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `f32`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:77:40
@@ -228,15 +228,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u32` in the defining scope
 LL |     assert::is_transmutable::<   u8,   u32>();
    |                                        ^^^ `u8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u32`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:78:40
@@ -244,15 +244,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<   u8,   u64>();
    |                                        ^^^ `u8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:79:40
@@ -260,15 +260,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<   u8,   i64>();
    |                                        ^^^ `u8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:80:40
@@ -276,15 +276,15 @@ error[E0277]: `u8` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<   u8,   f64>();
    |                                        ^^^ `u8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:81:39
@@ -292,15 +292,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u128` in the defining scope
 LL |     assert::is_transmutable::<   u8,  u128>();
    |                                       ^^^^ `u8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:82:39
@@ -308,15 +308,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i128` in the defining scope
 LL |     assert::is_transmutable::<   u8,  i128>();
    |                                       ^^^^ `u8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:84:40
@@ -324,15 +324,15 @@ error[E0277]: `i16` cannot be safely transmuted into `i32` in the defining scope
 LL |     assert::is_transmutable::<  i16,   i32>();
    |                                        ^^^ `i16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `i32`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:85:40
@@ -340,15 +340,15 @@ error[E0277]: `i16` cannot be safely transmuted into `f32` in the defining scope
 LL |     assert::is_transmutable::<  i16,   f32>();
    |                                        ^^^ `i16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `f32`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:86:40
@@ -356,15 +356,15 @@ error[E0277]: `i16` cannot be safely transmuted into `u32` in the defining scope
 LL |     assert::is_transmutable::<  i16,   u32>();
    |                                        ^^^ `i16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `u32`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:87:40
@@ -372,15 +372,15 @@ error[E0277]: `i16` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<  i16,   u64>();
    |                                        ^^^ `i16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:88:40
@@ -388,15 +388,15 @@ error[E0277]: `i16` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<  i16,   i64>();
    |                                        ^^^ `i16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:89:40
@@ -404,15 +404,15 @@ error[E0277]: `i16` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<  i16,   f64>();
    |                                        ^^^ `i16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:90:39
@@ -420,15 +420,15 @@ error[E0277]: `i16` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  i16,  u128>();
    |                                       ^^^^ `i16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:91:39
@@ -436,15 +436,15 @@ error[E0277]: `i16` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  i16,  i128>();
    |                                       ^^^^ `i16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:93:40
@@ -452,15 +452,15 @@ error[E0277]: `u16` cannot be safely transmuted into `i32` in the defining scope
 LL |     assert::is_transmutable::<  u16,   i32>();
    |                                        ^^^ `u16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `i32`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:94:40
@@ -468,15 +468,15 @@ error[E0277]: `u16` cannot be safely transmuted into `f32` in the defining scope
 LL |     assert::is_transmutable::<  u16,   f32>();
    |                                        ^^^ `u16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `f32`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:95:40
@@ -484,15 +484,15 @@ error[E0277]: `u16` cannot be safely transmuted into `u32` in the defining scope
 LL |     assert::is_transmutable::<  u16,   u32>();
    |                                        ^^^ `u16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `u32`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u32`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:96:40
@@ -500,15 +500,15 @@ error[E0277]: `u16` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<  u16,   u64>();
    |                                        ^^^ `u16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:97:40
@@ -516,15 +516,15 @@ error[E0277]: `u16` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<  u16,   i64>();
    |                                        ^^^ `u16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:98:40
@@ -532,15 +532,15 @@ error[E0277]: `u16` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<  u16,   f64>();
    |                                        ^^^ `u16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:99:39
@@ -548,15 +548,15 @@ error[E0277]: `u16` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  u16,  u128>();
    |                                       ^^^^ `u16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:100:39
@@ -564,15 +564,15 @@ error[E0277]: `u16` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  u16,  i128>();
    |                                       ^^^^ `u16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:102:40
@@ -580,15 +580,15 @@ error[E0277]: `i32` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<  i32,   u64>();
    |                                        ^^^ `i32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:103:40
@@ -596,15 +596,15 @@ error[E0277]: `i32` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<  i32,   i64>();
    |                                        ^^^ `i32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:104:40
@@ -612,15 +612,15 @@ error[E0277]: `i32` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<  i32,   f64>();
    |                                        ^^^ `i32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:105:39
@@ -628,15 +628,15 @@ error[E0277]: `i32` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  i32,  u128>();
    |                                       ^^^^ `i32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:106:39
@@ -644,15 +644,15 @@ error[E0277]: `i32` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  i32,  i128>();
    |                                       ^^^^ `i32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:108:40
@@ -660,15 +660,15 @@ error[E0277]: `f32` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<  f32,   u64>();
    |                                        ^^^ `f32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:109:40
@@ -676,15 +676,15 @@ error[E0277]: `f32` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<  f32,   i64>();
    |                                        ^^^ `f32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:110:40
@@ -692,15 +692,15 @@ error[E0277]: `f32` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<  f32,   f64>();
    |                                        ^^^ `f32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:111:39
@@ -708,15 +708,15 @@ error[E0277]: `f32` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  f32,  u128>();
    |                                       ^^^^ `f32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:112:39
@@ -724,15 +724,15 @@ error[E0277]: `f32` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  f32,  i128>();
    |                                       ^^^^ `f32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:114:40
@@ -740,15 +740,15 @@ error[E0277]: `u32` cannot be safely transmuted into `u64` in the defining scope
 LL |     assert::is_transmutable::<  u32,   u64>();
    |                                        ^^^ `u32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `u64`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:115:40
@@ -756,15 +756,15 @@ error[E0277]: `u32` cannot be safely transmuted into `i64` in the defining scope
 LL |     assert::is_transmutable::<  u32,   i64>();
    |                                        ^^^ `u32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `i64`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:116:40
@@ -772,15 +772,15 @@ error[E0277]: `u32` cannot be safely transmuted into `f64` in the defining scope
 LL |     assert::is_transmutable::<  u32,   f64>();
    |                                        ^^^ `u32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `f64`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `f64`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:117:39
@@ -788,15 +788,15 @@ error[E0277]: `u32` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  u32,  u128>();
    |                                       ^^^^ `u32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:118:39
@@ -804,15 +804,15 @@ error[E0277]: `u32` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  u32,  i128>();
    |                                       ^^^^ `u32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:120:39
@@ -820,15 +820,15 @@ error[E0277]: `u64` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  u64,  u128>();
    |                                       ^^^^ `u64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `u64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:121:39
@@ -836,15 +836,15 @@ error[E0277]: `u64` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  u64,  i128>();
    |                                       ^^^^ `u64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:123:39
@@ -852,15 +852,15 @@ error[E0277]: `i64` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  i64,  u128>();
    |                                       ^^^^ `i64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `i64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:124:39
@@ -868,15 +868,15 @@ error[E0277]: `i64` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  i64,  i128>();
    |                                       ^^^^ `i64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:126:39
@@ -884,15 +884,15 @@ error[E0277]: `f64` cannot be safely transmuted into `u128` in the defining scop
 LL |     assert::is_transmutable::<  f64,  u128>();
    |                                       ^^^^ `f64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, false, false, false, false>` is not implemented for `u128`
+   = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `u128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `f64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
   --> $DIR/numbers.rs:127:39
@@ -900,15 +900,15 @@ error[E0277]: `f64` cannot be safely transmuted into `i128` in the defining scop
 LL |     assert::is_transmutable::<  f64,  i128>();
    |                                       ^^^^ `f64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, false, false, false, false>` is not implemented for `i128`
+   = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `i128`
 note: required by a bound in `is_transmutable`
   --> $DIR/numbers.rs:12:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to 57 previous errors
 
diff --git a/src/test/ui/transmutability/primitives/unit.rs b/src/test/ui/transmutability/primitives/unit.rs
index 86d4740300df..1975a61de988 100644
--- a/src/test/ui/transmutability/primitives/unit.rs
+++ b/src/test/ui/transmutability/primitives/unit.rs
@@ -5,11 +5,16 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/primitives/unit.stderr b/src/test/ui/transmutability/primitives/unit.stderr
index cf27c0d17b33..8cabe44a0538 100644
--- a/src/test/ui/transmutability/primitives/unit.stderr
+++ b/src/test/ui/transmutability/primitives/unit.stderr
@@ -1,18 +1,24 @@
 error[E0277]: `()` cannot be safely transmuted into `u8` in the defining scope of `should_have_correct_size::Context`.
-  --> $DIR/unit.rs:23:35
+  --> $DIR/unit.rs:28:35
    |
 LL |     assert::is_transmutable::<(), u8, Context>();
    |                                   ^^ `()` cannot be safely transmuted into `u8` in the defining scope of `should_have_correct_size::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<(), should_have_correct_size::Context, true, true, true, true>` is not implemented for `u8`
+   = help: the trait `BikeshedIntrinsicFrom<(), should_have_correct_size::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `u8`
 note: required by a bound in `is_transmutable`
   --> $DIR/unit.rs:12:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/references.rs b/src/test/ui/transmutability/references.rs
index c6fd4c43e95c..af3ff0ec1d20 100644
--- a/src/test/ui/transmutability/references.rs
+++ b/src/test/ui/transmutability/references.rs
@@ -5,12 +5,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/references.stderr b/src/test/ui/transmutability/references.stderr
index 17ffcf64177e..e9c7b144a826 100644
--- a/src/test/ui/transmutability/references.stderr
+++ b/src/test/ui/transmutability/references.stderr
@@ -1,18 +1,25 @@
 error[E0277]: `&'static Unit` cannot be safely transmuted into `&'static Unit` in the defining scope of `assert::Context`.
-  --> $DIR/references.rs:19:52
+  --> $DIR/references.rs:26:52
    |
 LL |     assert::is_maybe_transmutable::<&'static Unit, &'static Unit>();
    |                                                    ^^^^^^^^^^^^^ `&'static Unit` cannot be safely transmuted into `&'static Unit` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<&'static Unit, assert::Context, true, true, true, true>` is not implemented for `&'static Unit`
+   = help: the trait `BikeshedIntrinsicFrom<&'static Unit, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `&'static Unit`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/references.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/structs/repr/should_handle_align.rs b/src/test/ui/transmutability/structs/repr/should_handle_align.rs
index 71720165ab06..ea9bf2a237ed 100644
--- a/src/test/ui/transmutability/structs/repr/should_handle_align.rs
+++ b/src/test/ui/transmutability/structs/repr/should_handle_align.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/structs/repr/should_handle_packed.rs b/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
index ae8acf504189..17dc995fcd96 100644
--- a/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
+++ b/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs
index 556be989dbc2..9a65b4d702da 100644
--- a/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs
+++ b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs
@@ -5,12 +5,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr
index 07355f7c2ad2..621dbee849f0 100644
--- a/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr
+++ b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr
@@ -1,194 +1,278 @@
 error[E0277]: `should_reject_repr_rust::unit::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:21:52
+  --> $DIR/should_require_well_defined_layout.rs:28:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `should_reject_repr_rust::unit::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::unit::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::unit::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::unit::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:22:47
+  --> $DIR/should_require_well_defined_layout.rs:29:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::unit::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::unit::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `should_reject_repr_rust::unit::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `should_reject_repr_rust::tuple::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:27:52
+  --> $DIR/should_require_well_defined_layout.rs:34:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `should_reject_repr_rust::tuple::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::tuple::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::tuple::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::tuple::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:28:47
+  --> $DIR/should_require_well_defined_layout.rs:35:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::tuple::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::tuple::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `should_reject_repr_rust::tuple::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `should_reject_repr_rust::braces::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:33:52
+  --> $DIR/should_require_well_defined_layout.rs:40:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `should_reject_repr_rust::braces::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::braces::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::braces::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::braces::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:34:47
+  --> $DIR/should_require_well_defined_layout.rs:41:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::braces::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::braces::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `should_reject_repr_rust::braces::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `aligned::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:39:52
+  --> $DIR/should_require_well_defined_layout.rs:46:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `aligned::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<aligned::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<aligned::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `aligned::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:40:47
+  --> $DIR/should_require_well_defined_layout.rs:47:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `aligned::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `aligned::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `aligned::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `packed::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:45:52
+  --> $DIR/should_require_well_defined_layout.rs:52:52
    |
 LL |         assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                    ^^ `packed::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<packed::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<packed::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `packed::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:46:47
+  --> $DIR/should_require_well_defined_layout.rs:53:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                               ^^^^^^^^^ `u128` cannot be safely transmuted into `packed::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `packed::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `packed::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `nested::repr_c` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:52:49
+  --> $DIR/should_require_well_defined_layout.rs:59:49
    |
 LL |         assert::is_maybe_transmutable::<repr_c, ()>();
    |                                                 ^^ `nested::repr_c` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<nested::repr_c, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<nested::repr_c, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `nested::repr_c` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:53:47
+  --> $DIR/should_require_well_defined_layout.rs:60:47
    |
 LL |         assert::is_maybe_transmutable::<u128, repr_c>();
    |                                               ^^^^^^ `u128` cannot be safely transmuted into `nested::repr_c` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `nested::repr_c`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `nested::repr_c`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 12 previous errors
 
diff --git a/src/test/ui/transmutability/structs/should_order_fields_correctly.rs b/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
index db49b914fe06..28724562bad2 100644
--- a/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
+++ b/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
@@ -6,12 +6,17 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/boolish.rs b/src/test/ui/transmutability/unions/boolish.rs
index 975118b99b7b..e469c497353b 100644
--- a/src/test/ui/transmutability/unions/boolish.rs
+++ b/src/test/ui/transmutability/unions/boolish.rs
@@ -7,12 +7,12 @@
 #![allow(incomplete_features)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_align.rs b/src/test/ui/transmutability/unions/repr/should_handle_align.rs
index e215799a2324..09c13cc4dc75 100644
--- a/src/test/ui/transmutability/unions/repr/should_handle_align.rs
+++ b/src/test/ui/transmutability/unions/repr/should_handle_align.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_packed.rs b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
index 34a53c7a80c4..24c2abd698e7 100644
--- a/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
+++ b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
index cec8e389f444..b1d5f71dcc58 100644
--- a/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
+++ b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
@@ -5,12 +5,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
index 2ed01b159ab0..523bde85adfa 100644
--- a/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
+++ b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
@@ -1,34 +1,48 @@
 error[E0277]: `should_reject_repr_rust::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:23:48
+  --> $DIR/should_require_well_defined_layout.rs:30:48
    |
 LL |     assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                ^^ `should_reject_repr_rust::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:24:43
+  --> $DIR/should_require_well_defined_layout.rs:31:43
    |
 LL |     assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                           ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `should_reject_repr_rust::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/transmutability/unions/should_pad_variants.rs b/src/test/ui/transmutability/unions/should_pad_variants.rs
index c4757900f9c3..cabe544677e0 100644
--- a/src/test/ui/transmutability/unions/should_pad_variants.rs
+++ b/src/test/ui/transmutability/unions/should_pad_variants.rs
@@ -6,11 +6,16 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_pad_variants.stderr b/src/test/ui/transmutability/unions/should_pad_variants.stderr
index 429f7211d17a..a823503d594e 100644
--- a/src/test/ui/transmutability/unions/should_pad_variants.stderr
+++ b/src/test/ui/transmutability/unions/should_pad_variants.stderr
@@ -1,18 +1,24 @@
 error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
-  --> $DIR/should_pad_variants.rs:39:36
+  --> $DIR/should_pad_variants.rs:44:36
    |
 LL |     assert::is_transmutable::<Src, Dst, Context>();
    |                                    ^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, true, true, true, true>` is not implemented for `Dst`
+   = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `Dst`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_pad_variants.rs:13:14
    |
-LL |     pub fn is_transmutable<Src, Dst, Context>()
-   |            --------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs b/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs
index 2493d71554ad..1007fdd79542 100644
--- a/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs
+++ b/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs
@@ -7,13 +7,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
-        // validity IS assumed --------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.rs b/src/test/ui/transmutability/unions/should_reject_contraction.rs
index e8138d0e046c..a24dfccd3187 100644
--- a/src/test/ui/transmutability/unions/should_reject_contraction.rs
+++ b/src/test/ui/transmutability/unions/should_reject_contraction.rs
@@ -5,12 +5,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.stderr b/src/test/ui/transmutability/unions/should_reject_contraction.stderr
index 99f589008172..41f0cedc3a31 100644
--- a/src/test/ui/transmutability/unions/should_reject_contraction.stderr
+++ b/src/test/ui/transmutability/unions/should_reject_contraction.stderr
@@ -4,15 +4,15 @@ error[E0277]: `Superset` cannot be safely transmuted into `Subset` in the defini
 LL |     assert::is_transmutable::<Superset, Subset>();
    |                                         ^^^^^^ `Superset` cannot be safely transmuted into `Subset` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Superset, assert::Context, false, false, false, true>` is not implemented for `Subset`
+   = help: the trait `BikeshedIntrinsicFrom<Superset, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` is not implemented for `Subset`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_contraction.rs:13:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/unions/should_reject_disjoint.rs b/src/test/ui/transmutability/unions/should_reject_disjoint.rs
index 16160e29a546..43aaa6905fd4 100644
--- a/src/test/ui/transmutability/unions/should_reject_disjoint.rs
+++ b/src/test/ui/transmutability/unions/should_reject_disjoint.rs
@@ -5,13 +5,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
-        // validity IS assumed --------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_disjoint.stderr b/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
index 5714e2bf320c..4323f9740665 100644
--- a/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
+++ b/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
@@ -1,34 +1,34 @@
 error[E0277]: `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
-  --> $DIR/should_reject_disjoint.rs:34:40
+  --> $DIR/should_reject_disjoint.rs:33:40
    |
 LL |     assert::is_maybe_transmutable::<A, B>();
    |                                        ^ `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, false, false, true, true>` is not implemented for `B`
+   = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: true }>` is not implemented for `B`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_reject_disjoint.rs:13:14
    |
 LL |     pub fn is_maybe_transmutable<Src, Dst>()
    |            --------------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
-  --> $DIR/should_reject_disjoint.rs:35:40
+  --> $DIR/should_reject_disjoint.rs:34:40
    |
 LL |     assert::is_maybe_transmutable::<B, A>();
    |                                        ^ `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, false, false, true, true>` is not implemented for `A`
+   = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: true }>` is not implemented for `A`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_reject_disjoint.rs:13:14
    |
 LL |     pub fn is_maybe_transmutable<Src, Dst>()
    |            --------------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/transmutability/unions/should_reject_intersecting.rs b/src/test/ui/transmutability/unions/should_reject_intersecting.rs
index 58e399fb9622..9cd4233ee745 100644
--- a/src/test/ui/transmutability/unions/should_reject_intersecting.rs
+++ b/src/test/ui/transmutability/unions/should_reject_intersecting.rs
@@ -6,13 +6,13 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // validity is NOT assumed ----------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // validity is NOT assumed --------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_intersecting.stderr b/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
index 92689a5f828b..e009888ae8d3 100644
--- a/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
+++ b/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
@@ -4,15 +4,15 @@ error[E0277]: `A` cannot be safely transmuted into `B` in the defining scope of
 LL |     assert::is_transmutable::<A, B>();
    |                                  ^ `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, false, false, false, true>` is not implemented for `B`
+   = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` is not implemented for `B`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_intersecting.rs:14:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error[E0277]: `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
   --> $DIR/should_reject_intersecting.rs:37:34
@@ -20,15 +20,15 @@ error[E0277]: `B` cannot be safely transmuted into `A` in the defining scope of
 LL |     assert::is_transmutable::<B, A>();
    |                                  ^ `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, false, false, false, true>` is not implemented for `A`
+   = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` is not implemented for `A`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_intersecting.rs:14:14
    |
 LL |     pub fn is_transmutable<Src, Dst>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs
index 5a8c810494c5..8a41669c65e7 100644
--- a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs
@@ -7,12 +7,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs
index 77ab4fa6bff4..dd57b877d78c 100644
--- a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs
@@ -7,12 +7,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs
index 2421b24cbf07..ebce8ce87dfd 100644
--- a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs
@@ -13,12 +13,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs
index 80b454fda560..546fcbaa3de2 100644
--- a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs
@@ -8,12 +8,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs
index 7c53c91e4eda..b9b74d18338a 100644
--- a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs
@@ -8,12 +8,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs
index c3f298f01632..5a0df09d4926 100644
--- a/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs
index 73f6aece51eb..0f69630cc64f 100644
--- a/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs
index 6d602601e96a..9c8345a8e91a 100644
--- a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr
index 3f7d08d0ae24..39b73302e364 100644
--- a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr
@@ -1,5 +1,5 @@
 error[E0446]: private type `src::Zst` in public interface
-  --> $DIR/should_accept_if_src_has_unreachable_field.rs:23:9
+  --> $DIR/should_accept_if_src_has_unreachable_field.rs:22:9
    |
 LL |     #[repr(C)] pub(self) struct Zst; // <- unreachable type
    |                -------------------- `src::Zst` declared as private
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs
index 1943fb8716a1..acf9f2302500 100644
--- a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr
index e961984e1893..76dc7f340755 100644
--- a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr
@@ -1,11 +1,11 @@
 error[E0603]: struct `Src` is private
-  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:38:36
+  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:37:36
    |
 LL |     assert::is_transmutable::<src::Src, dst::Dst, Context>();
    |                                    ^^^ private struct
    |
 note: the struct `Src` is defined here
-  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:23:16
+  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:22:16
    |
 LL |     #[repr(C)] pub(self) struct Src {
    |                ^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs
index fcf3f3a52780..e8c3fbc9a046 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs
@@ -10,8 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr
index 85124019e7f0..d5d6d431b6f6 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr
@@ -1,18 +1,18 @@
 error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
-  --> $DIR/should_reject_if_dst_has_private_field.rs:36:41
+  --> $DIR/should_reject_if_dst_has_private_field.rs:35:41
    |
 LL |     assert::is_transmutable::<src::Src, dst::Dst, Context>();
    |                                         ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `Dst`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_if_dst_has_private_field.rs:13:14
    |
 LL |     pub fn is_transmutable<Src, Dst, Context>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs
index 566b56467124..47bca27abaa8 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs
@@ -10,8 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr
index 0be564d93e2d..a1ca2ced53f2 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr
@@ -1,18 +1,18 @@
 error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
-  --> $DIR/should_reject_if_dst_has_private_variant.rs:37:41
+  --> $DIR/should_reject_if_dst_has_private_variant.rs:36:41
    |
 LL |     assert::is_transmutable::<src::Src, dst::Dst, Context>();
    |                                         ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `Dst`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_if_dst_has_private_variant.rs:13:14
    |
 LL |     pub fn is_transmutable<Src, Dst, Context>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs
index 35fff5966c85..662c32af17aa 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs
@@ -23,8 +23,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs
index 42799d803b02..d7e21676fd38 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs
@@ -12,8 +12,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr
index 95c68d452010..4e648664d5ab 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr
@@ -1,18 +1,18 @@
 error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
-  --> $DIR/should_reject_if_dst_has_unreachable_field.rs:38:41
+  --> $DIR/should_reject_if_dst_has_unreachable_field.rs:37:41
    |
 LL |     assert::is_transmutable::<src::Src, dst::Dst, Context>();
    |                                         ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `Dst`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_if_dst_has_unreachable_field.rs:15:14
    |
 LL |     pub fn is_transmutable<Src, Dst, Context>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs
index e13b32b30d96..c7b59f15b99c 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs
@@ -12,8 +12,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr
index 3391839e39e0..bd72d64ccd75 100644
--- a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr
@@ -1,30 +1,30 @@
 error[E0603]: struct `Dst` is private
-  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:39:46
+  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:38:46
    |
 LL |     assert::is_transmutable::<src::Src, dst::Dst, Context>();
    |                                              ^^^ private struct
    |
 note: the struct `Dst` is defined here
-  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:32:16
+  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:31:16
    |
 LL |     #[repr(C)] pub(self) struct Dst {
    |                ^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
-  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:39:41
+  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:38:41
    |
 LL |     assert::is_transmutable::<src::Src, dst::Dst, Context>();
    |                                         ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: false }>` is not implemented for `Dst`
 note: required by a bound in `is_transmutable`
   --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:15:14
    |
 LL |     pub fn is_transmutable<Src, Dst, Context>()
    |            --------------- required by a bound in this
 LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/transmute/main.stderr b/src/test/ui/transmute/main.stderr
index f48562094a4b..d519f03682b5 100644
--- a/src/test/ui/transmute/main.stderr
+++ b/src/test/ui/transmute/main.stderr
@@ -4,7 +4,7 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
 LL |     transmute(x)
    |     ^^^^^^^^^
    |
-   = note: `<C as TypeConstructor>::T` does not have a fixed size
+   = note: `<C as TypeConstructor<'_>>::T` does not have a fixed size
 
 error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
   --> $DIR/main.rs:17:17
diff --git a/src/test/ui/try-trait/bad-interconversion.stderr b/src/test/ui/try-trait/bad-interconversion.stderr
index 529f5f16c8fc..27e6a603acd9 100644
--- a/src/test/ui/try-trait/bad-interconversion.stderr
+++ b/src/test/ui/try-trait/bad-interconversion.stderr
@@ -22,13 +22,10 @@ LL |     Ok(Err(123_i32)?)
 error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result`
   --> $DIR/bad-interconversion.rs:11:12
    |
-LL | / fn option_to_result() -> Result<u64, String> {
-LL | |     Some(3)?;
-   | |            ^ use `.ok_or(...)?` to provide an error compatible with `Result<u64, String>`
-LL | |
-LL | |     Ok(10)
-LL | | }
-   | |_- this function returns a `Result`
+LL | fn option_to_result() -> Result<u64, String> {
+   | -------------------------------------------- this function returns a `Result`
+LL |     Some(3)?;
+   |            ^ use `.ok_or(...)?` to provide an error compatible with `Result<u64, String>`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `Result<u64, String>`
    = help: the following other types implement trait `FromResidual<R>`:
@@ -38,12 +35,10 @@ LL | | }
 error[E0277]: the `?` operator can only be used on `Result`s in a function that returns `Result`
   --> $DIR/bad-interconversion.rs:17:31
    |
-LL | / fn control_flow_to_result() -> Result<u64, String> {
-LL | |     Ok(ControlFlow::Break(123)?)
-   | |                               ^ this `?` produces `ControlFlow<{integer}, Infallible>`, which is incompatible with `Result<u64, String>`
-LL | |
-LL | | }
-   | |_- this function returns a `Result`
+LL | fn control_flow_to_result() -> Result<u64, String> {
+   | -------------------------------------------------- this function returns a `Result`
+LL |     Ok(ControlFlow::Break(123)?)
+   |                               ^ this `?` produces `ControlFlow<{integer}, Infallible>`, which is incompatible with `Result<u64, String>`
    |
    = help: the trait `FromResidual<ControlFlow<{integer}, Infallible>>` is not implemented for `Result<u64, String>`
    = help: the following other types implement trait `FromResidual<R>`:
@@ -53,12 +48,10 @@ LL | | }
 error[E0277]: the `?` operator can only be used on `Option`s, not `Result`s, in a function that returns `Option`
   --> $DIR/bad-interconversion.rs:22:22
    |
-LL | / fn result_to_option() -> Option<u16> {
-LL | |     Some(Err("hello")?)
-   | |                      ^ use `.ok()?` if you want to discard the `Result<Infallible, &str>` error information
-LL | |
-LL | | }
-   | |_- this function returns an `Option`
+LL | fn result_to_option() -> Option<u16> {
+   | ------------------------------------ this function returns an `Option`
+LL |     Some(Err("hello")?)
+   |                      ^ use `.ok()?` if you want to discard the `Result<Infallible, &str>` error information
    |
    = help: the trait `FromResidual<Result<Infallible, &str>>` is not implemented for `Option<u16>`
    = help: the following other types implement trait `FromResidual<R>`:
@@ -68,12 +61,10 @@ LL | | }
 error[E0277]: the `?` operator can only be used on `Option`s in a function that returns `Option`
   --> $DIR/bad-interconversion.rs:27:33
    |
-LL | / fn control_flow_to_option() -> Option<u64> {
-LL | |     Some(ControlFlow::Break(123)?)
-   | |                                 ^ this `?` produces `ControlFlow<{integer}, Infallible>`, which is incompatible with `Option<u64>`
-LL | |
-LL | | }
-   | |_- this function returns an `Option`
+LL | fn control_flow_to_option() -> Option<u64> {
+   | ------------------------------------------ this function returns an `Option`
+LL |     Some(ControlFlow::Break(123)?)
+   |                                 ^ this `?` produces `ControlFlow<{integer}, Infallible>`, which is incompatible with `Option<u64>`
    |
    = help: the trait `FromResidual<ControlFlow<{integer}, Infallible>>` is not implemented for `Option<u64>`
    = help: the following other types implement trait `FromResidual<R>`:
@@ -83,12 +74,10 @@ LL | | }
 error[E0277]: the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow`
   --> $DIR/bad-interconversion.rs:32:39
    |
-LL | / fn result_to_control_flow() -> ControlFlow<String> {
-LL | |     ControlFlow::Continue(Err("hello")?)
-   | |                                       ^ this `?` produces `Result<Infallible, &str>`, which is incompatible with `ControlFlow<String>`
-LL | |
-LL | | }
-   | |_- this function returns a `ControlFlow`
+LL | fn result_to_control_flow() -> ControlFlow<String> {
+   | -------------------------------------------------- this function returns a `ControlFlow`
+LL |     ControlFlow::Continue(Err("hello")?)
+   |                                       ^ this `?` produces `Result<Infallible, &str>`, which is incompatible with `ControlFlow<String>`
    |
    = help: the trait `FromResidual<Result<Infallible, &str>>` is not implemented for `ControlFlow<String>`
    = help: the trait `FromResidual` is implemented for `ControlFlow<B, C>`
@@ -96,13 +85,10 @@ LL | | }
 error[E0277]: the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow`
   --> $DIR/bad-interconversion.rs:37:12
    |
-LL | / fn option_to_control_flow() -> ControlFlow<u64> {
-LL | |     Some(3)?;
-   | |            ^ this `?` produces `Option<Infallible>`, which is incompatible with `ControlFlow<u64>`
-LL | |
-LL | |     ControlFlow::Break(10)
-LL | | }
-   | |_- this function returns a `ControlFlow`
+LL | fn option_to_control_flow() -> ControlFlow<u64> {
+   | ----------------------------------------------- this function returns a `ControlFlow`
+LL |     Some(3)?;
+   |            ^ this `?` produces `Option<Infallible>`, which is incompatible with `ControlFlow<u64>`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `ControlFlow<u64>`
    = help: the trait `FromResidual` is implemented for `ControlFlow<B, C>`
@@ -110,13 +96,10 @@ LL | | }
 error[E0277]: the `?` operator in a function that returns `ControlFlow<B, _>` can only be used on other `ControlFlow<B, _>`s (with the same Break type)
   --> $DIR/bad-interconversion.rs:43:29
    |
-LL | / fn control_flow_to_control_flow() -> ControlFlow<i64> {
-LL | |     ControlFlow::Break(4_u8)?;
-   | |                             ^ this `?` produces `ControlFlow<u8, Infallible>`, which is incompatible with `ControlFlow<i64>`
-LL | |
-LL | |     ControlFlow::Continue(())
-LL | | }
-   | |_- this function returns a `ControlFlow`
+LL | fn control_flow_to_control_flow() -> ControlFlow<i64> {
+   | ----------------------------------------------------- this function returns a `ControlFlow`
+LL |     ControlFlow::Break(4_u8)?;
+   |                             ^ this `?` produces `ControlFlow<u8, Infallible>`, which is incompatible with `ControlFlow<i64>`
    |
    = help: the trait `FromResidual<ControlFlow<u8, Infallible>>` is not implemented for `ControlFlow<i64>`
    = note: unlike `Result`, there's no `From`-conversion performed for `ControlFlow`
diff --git a/src/test/ui/try-trait/option-to-result.stderr b/src/test/ui/try-trait/option-to-result.stderr
index ae5c3ad62828..fabc1ff2c762 100644
--- a/src/test/ui/try-trait/option-to-result.stderr
+++ b/src/test/ui/try-trait/option-to-result.stderr
@@ -1,13 +1,11 @@
 error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result`
   --> $DIR/option-to-result.rs:5:6
    |
-LL | / fn test_result() -> Result<(),()> {
-LL | |     let a:Option<()> = Some(());
-LL | |     a?;
-   | |      ^ use `.ok_or(...)?` to provide an error compatible with `Result<(), ()>`
-LL | |     Ok(())
-LL | | }
-   | |_- this function returns a `Result`
+LL | fn test_result() -> Result<(),()> {
+   | --------------------------------- this function returns a `Result`
+LL |     let a:Option<()> = Some(());
+LL |     a?;
+   |      ^ use `.ok_or(...)?` to provide an error compatible with `Result<(), ()>`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `Result<(), ()>`
    = help: the following other types implement trait `FromResidual<R>`:
@@ -17,13 +15,11 @@ LL | | }
 error[E0277]: the `?` operator can only be used on `Option`s, not `Result`s, in a function that returns `Option`
   --> $DIR/option-to-result.rs:11:6
    |
-LL | / fn test_option() -> Option<i32>{
-LL | |     let a:Result<i32, i32> = Ok(5);
-LL | |     a?;
-   | |      ^ use `.ok()?` if you want to discard the `Result<Infallible, i32>` error information
-LL | |     Some(5)
-LL | | }
-   | |_- this function returns an `Option`
+LL | fn test_option() -> Option<i32>{
+   | ------------------------------- this function returns an `Option`
+LL |     let a:Result<i32, i32> = Ok(5);
+LL |     a?;
+   |      ^ use `.ok()?` if you want to discard the `Result<Infallible, i32>` error information
    |
    = help: the trait `FromResidual<Result<Infallible, i32>>` is not implemented for `Option<i32>`
    = help: the following other types implement trait `FromResidual<R>`:
diff --git a/src/test/ui/try-trait/try-on-option-diagnostics.stderr b/src/test/ui/try-trait/try-on-option-diagnostics.stderr
index a6badd190388..9ee540c79fdd 100644
--- a/src/test/ui/try-trait/try-on-option-diagnostics.stderr
+++ b/src/test/ui/try-trait/try-on-option-diagnostics.stderr
@@ -1,51 +1,44 @@
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option-diagnostics.rs:7:6
    |
-LL | / fn a_function() -> u32 {
-LL | |     let x: Option<u32> = None;
-LL | |     x?;
-   | |      ^ cannot use the `?` operator in a function that returns `u32`
-LL | |     22
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn a_function() -> u32 {
+   | ---------------------- this function should return `Result` or `Option` to accept `?`
+LL |     let x: Option<u32> = None;
+LL |     x?;
+   |      ^ cannot use the `?` operator in a function that returns `u32`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `u32`
 
 error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option-diagnostics.rs:14:10
    |
-LL |       let a_closure = || {
-   |  _____________________-
-LL | |         let x: Option<u32> = None;
-LL | |         x?;
-   | |          ^ cannot use the `?` operator in a closure that returns `{integer}`
-LL | |         22
-LL | |     };
-   | |_____- this function should return `Result` or `Option` to accept `?`
+LL |     let a_closure = || {
+   |                     -- this function should return `Result` or `Option` to accept `?`
+LL |         let x: Option<u32> = None;
+LL |         x?;
+   |          ^ cannot use the `?` operator in a closure that returns `{integer}`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `{integer}`
 
 error[E0277]: the `?` operator can only be used in a method that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option-diagnostics.rs:26:14
    |
-LL | /         fn a_method() {
-LL | |             let x: Option<u32> = None;
-LL | |             x?;
-   | |              ^ cannot use the `?` operator in a method that returns `()`
-LL | |         }
-   | |_________- this function should return `Result` or `Option` to accept `?`
+LL |         fn a_method() {
+   |         ------------- this function should return `Result` or `Option` to accept `?`
+LL |             let x: Option<u32> = None;
+LL |             x?;
+   |              ^ cannot use the `?` operator in a method that returns `()`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `()`
 
 error[E0277]: the `?` operator can only be used in a trait method that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option-diagnostics.rs:39:14
    |
-LL | /         fn a_trait_method() {
-LL | |             let x: Option<u32> = None;
-LL | |             x?;
-   | |              ^ cannot use the `?` operator in a trait method that returns `()`
-LL | |         }
-   | |_________- this function should return `Result` or `Option` to accept `?`
+LL |         fn a_trait_method() {
+   |         ------------------- this function should return `Result` or `Option` to accept `?`
+LL |             let x: Option<u32> = None;
+LL |             x?;
+   |              ^ cannot use the `?` operator in a trait method that returns `()`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `()`
 
diff --git a/src/test/ui/try-trait/try-on-option.stderr b/src/test/ui/try-trait/try-on-option.stderr
index ba85a7cada23..fad6a1fe8237 100644
--- a/src/test/ui/try-trait/try-on-option.stderr
+++ b/src/test/ui/try-trait/try-on-option.stderr
@@ -1,13 +1,11 @@
 error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result`
   --> $DIR/try-on-option.rs:5:6
    |
-LL | / fn foo() -> Result<u32, ()> {
-LL | |     let x: Option<u32> = None;
-LL | |     x?;
-   | |      ^ use `.ok_or(...)?` to provide an error compatible with `Result<u32, ()>`
-LL | |     Ok(22)
-LL | | }
-   | |_- this function returns a `Result`
+LL | fn foo() -> Result<u32, ()> {
+   | --------------------------- this function returns a `Result`
+LL |     let x: Option<u32> = None;
+LL |     x?;
+   |      ^ use `.ok_or(...)?` to provide an error compatible with `Result<u32, ()>`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `Result<u32, ()>`
    = help: the following other types implement trait `FromResidual<R>`:
@@ -17,13 +15,11 @@ LL | | }
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-on-option.rs:11:6
    |
-LL | / fn bar() -> u32 {
-LL | |     let x: Option<u32> = None;
-LL | |     x?;
-   | |      ^ cannot use the `?` operator in a function that returns `u32`
-LL | |     22
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn bar() -> u32 {
+   | --------------- this function should return `Result` or `Option` to accept `?`
+LL |     let x: Option<u32> = None;
+LL |     x?;
+   |      ^ cannot use the `?` operator in a function that returns `u32`
    |
    = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `u32`
 
diff --git a/src/test/ui/try-trait/try-operator-on-main.stderr b/src/test/ui/try-trait/try-operator-on-main.stderr
index ad55f40b5b63..7cd38e0cf95e 100644
--- a/src/test/ui/try-trait/try-operator-on-main.stderr
+++ b/src/test/ui/try-trait/try-operator-on-main.stderr
@@ -1,15 +1,11 @@
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-operator-on-main.rs:7:31
    |
-LL | / fn main() {
-LL | |     // error for a `Try` type on a non-`Try` fn
-LL | |     std::fs::File::open("foo")?;
-   | |                               ^ cannot use the `?` operator in a function that returns `()`
-LL | |
-...  |
-LL | |     try_trait_generic::<()>();
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn main() {
+   | --------- this function should return `Result` or `Option` to accept `?`
+LL |     // error for a `Try` type on a non-`Try` fn
+LL |     std::fs::File::open("foo")?;
+   |                               ^ cannot use the `?` operator in a function that returns `()`
    |
    = help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()`
 
@@ -24,17 +20,11 @@ LL |     ()?;
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
   --> $DIR/try-operator-on-main.rs:10:7
    |
-LL | / fn main() {
-LL | |     // error for a `Try` type on a non-`Try` fn
-LL | |     std::fs::File::open("foo")?;
-LL | |
-LL | |     // a non-`Try` type on a non-`Try` fn
-LL | |     ()?;
-   | |       ^ cannot use the `?` operator in a function that returns `()`
-...  |
-LL | |     try_trait_generic::<()>();
-LL | | }
-   | |_- this function should return `Result` or `Option` to accept `?`
+LL | fn main() {
+   | --------- this function should return `Result` or `Option` to accept `?`
+...
+LL |     ()?;
+   |       ^ cannot use the `?` operator in a function that returns `()`
    |
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
diff --git a/src/test/ui/tuple/builtin-fail.rs b/src/test/ui/tuple/builtin-fail.rs
new file mode 100644
index 000000000000..31208096151d
--- /dev/null
+++ b/src/test/ui/tuple/builtin-fail.rs
@@ -0,0 +1,19 @@
+#![feature(tuple_trait)]
+
+fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+
+struct TupleStruct(i32, i32);
+
+fn from_param_env<T>() {
+    assert_is_tuple::<T>();
+    //~^ ERROR `T` is not a tuple
+}
+
+fn main() {
+    assert_is_tuple::<i32>();
+    //~^ ERROR `i32` is not a tuple
+    assert_is_tuple::<(i32)>();
+    //~^ ERROR `i32` is not a tuple
+    assert_is_tuple::<TupleStruct>();
+    //~^ ERROR `TupleStruct` is not a tuple
+}
diff --git a/src/test/ui/tuple/builtin-fail.stderr b/src/test/ui/tuple/builtin-fail.stderr
new file mode 100644
index 000000000000..e3e29a73fdc0
--- /dev/null
+++ b/src/test/ui/tuple/builtin-fail.stderr
@@ -0,0 +1,55 @@
+error[E0277]: `T` is not a tuple
+  --> $DIR/builtin-fail.rs:8:23
+   |
+LL |     assert_is_tuple::<T>();
+   |                       ^ the trait `Tuple` is not implemented for `T`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+help: consider restricting type parameter `T`
+   |
+LL | fn from_param_env<T: std::marker::Tuple>() {
+   |                    ++++++++++++++++++++
+
+error[E0277]: `i32` is not a tuple
+  --> $DIR/builtin-fail.rs:13:23
+   |
+LL |     assert_is_tuple::<i32>();
+   |                       ^^^ the trait `Tuple` is not implemented for `i32`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+
+error[E0277]: `i32` is not a tuple
+  --> $DIR/builtin-fail.rs:15:24
+   |
+LL |     assert_is_tuple::<(i32)>();
+   |                        ^^^ the trait `Tuple` is not implemented for `i32`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+
+error[E0277]: `TupleStruct` is not a tuple
+  --> $DIR/builtin-fail.rs:17:23
+   |
+LL |     assert_is_tuple::<TupleStruct>();
+   |                       ^^^^^^^^^^^ the trait `Tuple` is not implemented for `TupleStruct`
+   |
+note: required by a bound in `assert_is_tuple`
+  --> $DIR/builtin-fail.rs:3:23
+   |
+LL | fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+   |                       ^^^^^^^^^^^^^^^^^^ required by this bound in `assert_is_tuple`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/tuple/builtin.rs b/src/test/ui/tuple/builtin.rs
new file mode 100644
index 000000000000..d87ce526357e
--- /dev/null
+++ b/src/test/ui/tuple/builtin.rs
@@ -0,0 +1,20 @@
+// check-pass
+
+#![feature(tuple_trait)]
+
+fn assert_is_tuple<T: std::marker::Tuple + ?Sized>() {}
+
+struct Unsized([u8]);
+
+fn from_param_env<T: std::marker::Tuple + ?Sized>() {
+    assert_is_tuple::<T>();
+}
+
+fn main() {
+    assert_is_tuple::<()>();
+    assert_is_tuple::<(i32,)>();
+    assert_is_tuple::<(Unsized,)>();
+    from_param_env::<()>();
+    from_param_env::<(i32,)>();
+    from_param_env::<(Unsized,)>();
+}
diff --git a/src/test/ui/tuple/wrong_argument_ice-3.stderr b/src/test/ui/tuple/wrong_argument_ice-3.stderr
index 968cb75db763..f3a547fa2382 100644
--- a/src/test/ui/tuple/wrong_argument_ice-3.stderr
+++ b/src/test/ui/tuple/wrong_argument_ice-3.stderr
@@ -19,7 +19,7 @@ LL |     pub fn push(&mut self, value: T) {
 help: remove the extra argument
    |
 LL |         groups.push(/* (Vec<String>, Vec<Process>) */);
-   |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/tuple/wrong_argument_ice-4.stderr b/src/test/ui/tuple/wrong_argument_ice-4.stderr
index 828ae21b4808..a2686ab9440e 100644
--- a/src/test/ui/tuple/wrong_argument_ice-4.stderr
+++ b/src/test/ui/tuple/wrong_argument_ice-4.stderr
@@ -16,7 +16,7 @@ LL |     (|| {})(|| {
 help: remove the extra argument
    |
 LL |     (|| {})();
-   |     ~~~~~~~~~
+   |            ~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-alias-enum-variants/enum-variant-priority-higher-than-other-inherent.stderr b/src/test/ui/type-alias-enum-variants/enum-variant-priority-higher-than-other-inherent.stderr
index 006253f84320..eb58ee73ca21 100644
--- a/src/test/ui/type-alias-enum-variants/enum-variant-priority-higher-than-other-inherent.stderr
+++ b/src/test/ui/type-alias-enum-variants/enum-variant-priority-higher-than-other-inherent.stderr
@@ -12,7 +12,7 @@ LL |     V(u8)
 help: provide the argument
    |
 LL |     <E>::V(/* u8 */);
-   |     ~~~~~~~~~~~~~~~~
+   |           ~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/enum-variant-priority-higher-than-other-inherent.rs:22:17
diff --git a/src/test/ui/type-alias-impl-trait/closure_args.rs b/src/test/ui/type-alias-impl-trait/closure_args.rs
new file mode 100644
index 000000000000..c5e7af81d3dd
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/closure_args.rs
@@ -0,0 +1,16 @@
+// check-pass
+
+// regression test for https://github.com/rust-lang/rust/issues/100800
+
+#![feature(type_alias_impl_trait)]
+
+trait Anything {}
+impl<T> Anything for T {}
+type Input = impl Anything;
+fn run<F: FnOnce(Input) -> ()>(f: F, i: Input) {
+    f(i);
+}
+
+fn main() {
+    run(|x: u32| {println!("{x}");}, 0);
+}
diff --git a/src/test/ui/type-alias-impl-trait/closure_args2.rs b/src/test/ui/type-alias-impl-trait/closure_args2.rs
new file mode 100644
index 000000000000..82386c280a8e
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/closure_args2.rs
@@ -0,0 +1,23 @@
+// run-pass
+
+#![feature(type_alias_impl_trait)]
+
+trait Foo {
+    // This was reachable in https://github.com/rust-lang/rust/issues/100800
+    fn foo(&self) { unreachable!() }
+}
+impl<T> Foo for T {}
+
+struct B;
+impl B {
+    fn foo(&self) {}
+}
+
+type Input = impl Foo;
+fn run1<F: FnOnce(Input)>(f: F, i: Input) {f(i)}
+fn run2<F: FnOnce(B)>(f: F, i: B) {f(i)}
+
+fn main() {
+    run1(|x: B| {x.foo()}, B);
+    run2(|x: B| {x.foo()}, B);
+}
diff --git a/src/test/ui/type-alias-impl-trait/constrain_inputs.rs b/src/test/ui/type-alias-impl-trait/constrain_inputs.rs
index c32174288ee6..03fb64b7b94d 100644
--- a/src/test/ui/type-alias-impl-trait/constrain_inputs.rs
+++ b/src/test/ui/type-alias-impl-trait/constrain_inputs.rs
@@ -1,17 +1,33 @@
-// check-pass
-
 #![feature(type_alias_impl_trait)]
 
-mod foo {
+mod lifetime_params {
     type Ty<'a> = impl Sized;
     fn defining(s: &str) -> Ty<'_> { s }
     fn execute(ty: Ty<'_>) -> &str { todo!() }
+    //~^ ERROR return type references an anonymous lifetime, which is not constrained by the fn input types
+
+    type BadFnSig = fn(Ty<'_>) -> &str;
+    //~^ ERROR return type references an anonymous lifetime, which is not constrained by the fn input types
+    type BadTraitRef = dyn Fn(Ty<'_>) -> &str;
+    //~^ ERROR binding for associated type `Output` references an anonymous lifetime
 }
 
-mod bar {
+mod lifetime_params_2 {
     type Ty<'a> = impl FnOnce() -> &'a str;
     fn defining(s: &str) -> Ty<'_> { move || s }
     fn execute(ty: Ty<'_>) -> &str { ty() }
+    //~^ ERROR return type references an anonymous lifetime, which is not constrained by the fn input types
+}
+
+// regression test for https://github.com/rust-lang/rust/issues/97104
+mod type_params {
+    type Ty<T> = impl Sized;
+    fn define<T>(s: T) -> Ty<T> { s }
+
+    type BadFnSig = fn(Ty<&str>) -> &str;
+    //~^ ERROR return type references an anonymous lifetime, which is not constrained by the fn input types
+    type BadTraitRef = dyn Fn(Ty<&str>) -> &str;
+    //~^ ERROR binding for associated type `Output` references an anonymous lifetime
 }
 
 fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/constrain_inputs.stderr b/src/test/ui/type-alias-impl-trait/constrain_inputs.stderr
new file mode 100644
index 000000000000..93953fd06d1f
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/constrain_inputs.stderr
@@ -0,0 +1,58 @@
+error[E0581]: return type references an anonymous lifetime, which is not constrained by the fn input types
+  --> $DIR/constrain_inputs.rs:6:31
+   |
+LL |     fn execute(ty: Ty<'_>) -> &str { todo!() }
+   |                               ^^^^
+   |
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
+
+error[E0581]: return type references an anonymous lifetime, which is not constrained by the fn input types
+  --> $DIR/constrain_inputs.rs:9:35
+   |
+LL |     type BadFnSig = fn(Ty<'_>) -> &str;
+   |                                   ^^^^
+   |
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
+
+error[E0582]: binding for associated type `Output` references an anonymous lifetime, which does not appear in the trait input types
+  --> $DIR/constrain_inputs.rs:11:42
+   |
+LL |     type BadTraitRef = dyn Fn(Ty<'_>) -> &str;
+   |                                          ^^^^
+   |
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
+
+error[E0581]: return type references an anonymous lifetime, which is not constrained by the fn input types
+  --> $DIR/constrain_inputs.rs:18:31
+   |
+LL |     fn execute(ty: Ty<'_>) -> &str { ty() }
+   |                               ^^^^
+   |
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
+
+error[E0581]: return type references an anonymous lifetime, which is not constrained by the fn input types
+  --> $DIR/constrain_inputs.rs:27:37
+   |
+LL |     type BadFnSig = fn(Ty<&str>) -> &str;
+   |                                     ^^^^
+   |
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
+
+error[E0582]: binding for associated type `Output` references an anonymous lifetime, which does not appear in the trait input types
+  --> $DIR/constrain_inputs.rs:29:44
+   |
+LL |     type BadTraitRef = dyn Fn(Ty<&str>) -> &str;
+   |                                            ^^^^
+   |
+   = note: lifetimes appearing in an associated or opaque type are not considered constrained
+   = note: consider introducing a named lifetime parameter
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0581, E0582.
+For more information about an error, try `rustc --explain E0581`.
diff --git a/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.rs b/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.rs
new file mode 100644
index 000000000000..3bae0f173099
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.rs
@@ -0,0 +1,31 @@
+#![feature(type_alias_impl_trait)]
+
+trait Static: 'static {}
+impl Static for () {}
+
+type Gal<T> = impl Static;
+fn _defining<T>() -> Gal<T> {}
+
+trait Callable<Arg> { type Output; }
+
+/// We can infer `<C as Callable<Arg>>::Output: 'static`,
+/// because we know `C: 'static` and `Arg: 'static`,
+fn box_str<C, Arg>(s: C::Output) -> Box<dyn AsRef<str> + 'static>
+where
+    Arg: Static,
+    C: ?Sized + Callable<Arg> + 'static,
+    C::Output: AsRef<str>,
+{
+    Box::new(s)
+}
+
+fn extend_lifetime(s: &str) -> Box<dyn AsRef<str> + 'static> {
+    type MalformedTy = dyn for<'a> Callable<Gal<&'a ()>, Output = &'a str>;
+    //~^ ERROR binding for associated type `Output` references lifetime `'a`
+    box_str::<MalformedTy, _>(s)
+}
+
+fn main() {
+    let extended = extend_lifetime(&String::from("hello"));
+    println!("{}", extended.as_ref().as_ref());
+}
diff --git a/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.stderr b/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.stderr
new file mode 100644
index 000000000000..d5fc46cb1f59
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.stderr
@@ -0,0 +1,9 @@
+error[E0582]: binding for associated type `Output` references lifetime `'a`, which does not appear in the trait input types
+  --> $DIR/constrain_inputs_unsound.rs:23:58
+   |
+LL |     type MalformedTy = dyn for<'a> Callable<Gal<&'a ()>, Output = &'a str>;
+   |                                                          ^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0582`.
diff --git a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.rs b/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.rs
index 811832848d9d..9a50c0f988a5 100644
--- a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.rs
+++ b/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.rs
@@ -1,8 +1,9 @@
 // compile-flags: --edition=2021
+// check-pass
 #![feature(type_alias_impl_trait)]
 
 fn main() {
-    type T = impl Copy; //~ ERROR unconstrained opaque type
+    type T = impl Copy;
     let foo: T = (1u32, 2u32);
     let (a, b): (u32, u32) = foo;
 }
diff --git a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.stderr b/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.stderr
deleted file mode 100644
index 03b172e6de57..000000000000
--- a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug.stderr
+++ /dev/null
@@ -1,10 +0,0 @@
-error: unconstrained opaque type
-  --> $DIR/cross_inference_pattern_bug.rs:5:14
-   |
-LL |     type T = impl Copy;
-   |              ^^^^^^^^^
-   |
-   = note: `T` must be used in combination with a concrete type within the same module
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.rs b/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.rs
index 328096d44b4b..b929122a6c23 100644
--- a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.rs
+++ b/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.rs
@@ -1,13 +1,13 @@
-// known-bug: #96572
 // compile-flags: --edition=2021 --crate-type=lib
 // rustc-env:RUST_BACKTRACE=0
+// check-pass
 
 // tracked in https://github.com/rust-lang/rust/issues/96572
 
 #![feature(type_alias_impl_trait)]
 
 fn main() {
-    type T = impl Copy;  // error: unconstrained opaque type
+    type T = impl Copy;
     let foo: T = (1u32, 2u32);
-    let (a, b) = foo; // removing this line makes the code compile
+    let (a, b) = foo; // this line used to make the code fail
 }
diff --git a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.stderr b/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.stderr
deleted file mode 100644
index 8aa1f4956399..000000000000
--- a/src/test/ui/type-alias-impl-trait/cross_inference_pattern_bug_no_type.stderr
+++ /dev/null
@@ -1,10 +0,0 @@
-error: unconstrained opaque type
-  --> $DIR/cross_inference_pattern_bug_no_type.rs:10:14
-   |
-LL |     type T = impl Copy;  // error: unconstrained opaque type
-   |              ^^^^^^^^^
-   |
-   = note: `T` must be used in combination with a concrete type within the same module
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds.rs b/src/test/ui/type-alias-impl-trait/implied_bounds.rs
new file mode 100644
index 000000000000..53cbf8d22900
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds.rs
@@ -0,0 +1,51 @@
+#![feature(type_alias_impl_trait)]
+
+type WithLifetime<'a> = impl Equals<SelfType = ()>;
+fn _defining_use<'a>() -> WithLifetime<'a> {}
+
+trait Convert<'a> {
+    type Witness;
+    fn convert<'b, T: ?Sized>(_proof: &'b Self::Witness, x: &'a T) -> &'b T;
+}
+
+impl<'a> Convert<'a> for () {
+    type Witness = WithLifetime<'a>;
+
+    fn convert<'b, T: ?Sized>(_proof: &'b WithLifetime<'a>, x: &'a T) -> &'b T {
+        // compiler used to think it gets to assume 'a: 'b here because
+        // of the `&'b WithLifetime<'a>` argument
+        x
+        //~^ ERROR lifetime may not live long enough
+    }
+}
+
+fn extend_lifetime<'a, 'b, T: ?Sized>(x: &'a T) -> &'b T {
+    WithLifetime::<'a>::convert_helper::<(), T>(&(), x)
+}
+
+trait Equals {
+    type SelfType;
+    fn convert_helper<'a, 'b, W: Convert<'a, Witness = Self>, T: ?Sized>(
+        proof: &'b Self::SelfType,
+        x: &'a T,
+    ) -> &'b T;
+}
+
+impl<S> Equals for S {
+    type SelfType = Self;
+    fn convert_helper<'a, 'b, W: Convert<'a, Witness = Self>, T: ?Sized>(
+        proof: &'b Self,
+        x: &'a T,
+    ) -> &'b T {
+        W::convert(proof, x)
+    }
+}
+
+fn main() {
+    let r;
+    {
+        let x = String::from("Hello World?");
+        r = extend_lifetime(&x);
+    }
+    println!("{}", r);
+}
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds.stderr b/src/test/ui/type-alias-impl-trait/implied_bounds.stderr
new file mode 100644
index 000000000000..6f11b66634b2
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds.stderr
@@ -0,0 +1,16 @@
+error: lifetime may not live long enough
+  --> $DIR/implied_bounds.rs:17:9
+   |
+LL | impl<'a> Convert<'a> for () {
+   |      -- lifetime `'a` defined here
+...
+LL |     fn convert<'b, T: ?Sized>(_proof: &'b WithLifetime<'a>, x: &'a T) -> &'b T {
+   |                -- lifetime `'b` defined here
+...
+LL |         x
+   |         ^ associated function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
+   |
+   = help: consider adding the following bound: `'a: 'b`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds2.rs b/src/test/ui/type-alias-impl-trait/implied_bounds2.rs
new file mode 100644
index 000000000000..b4c4c013cd25
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds2.rs
@@ -0,0 +1,10 @@
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+
+type Ty<'a, A> = impl Sized + 'a;
+fn defining<'a, A>() -> Ty<'a, A> {}
+fn assert_static<T: 'static>() {}
+fn test<'a, A>() where Ty<'a, A>: 'static, { assert_static::<Ty<'a, A>>() }
+
+fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds3.rs b/src/test/ui/type-alias-impl-trait/implied_bounds3.rs
new file mode 100644
index 000000000000..e39c613281dc
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds3.rs
@@ -0,0 +1,18 @@
+// check-pass
+
+fn foo<F>(_: F)
+where
+    F: 'static,
+{
+}
+
+fn from<F: Send>(f: F) -> impl Send {
+    f
+}
+
+fn bar<T>() {
+    foo(from(|| ()))
+}
+
+fn main() {
+}
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds_closure.rs b/src/test/ui/type-alias-impl-trait/implied_bounds_closure.rs
new file mode 100644
index 000000000000..4cf35f951904
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds_closure.rs
@@ -0,0 +1,31 @@
+trait StaticDefaultRef: 'static {
+    fn default_ref() -> &'static Self;
+}
+
+impl StaticDefaultRef for str {
+    fn default_ref() -> &'static str {
+        ""
+    }
+}
+
+fn into_impl(x: &str) -> &(impl ?Sized + AsRef<str> + StaticDefaultRef + '_) {
+    x
+}
+
+fn extend_lifetime<'a>(x: &'a str) -> &'static str {
+    let t = into_impl(x);
+    helper(|_| t) //~ ERROR lifetime may not live long enough
+}
+
+fn helper<T: ?Sized + AsRef<str> + StaticDefaultRef>(f: impl FnOnce(&T) -> &T) -> &'static str {
+    f(T::default_ref()).as_ref()
+}
+
+fn main() {
+    let r;
+    {
+        let x = String::from("Hello World?");
+        r = extend_lifetime(&x);
+    }
+    println!("{}", r);
+}
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds_closure.stderr b/src/test/ui/type-alias-impl-trait/implied_bounds_closure.stderr
new file mode 100644
index 000000000000..151564c3b45a
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds_closure.stderr
@@ -0,0 +1,11 @@
+error: lifetime may not live long enough
+  --> $DIR/implied_bounds_closure.rs:17:16
+   |
+LL | fn extend_lifetime<'a>(x: &'a str) -> &'static str {
+   |                    -- lifetime `'a` defined here
+LL |     let t = into_impl(x);
+LL |     helper(|_| t)
+   |                ^ returning this value requires that `'a` must outlive `'static`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds_from_types.rs b/src/test/ui/type-alias-impl-trait/implied_bounds_from_types.rs
new file mode 100644
index 000000000000..8023cd24f0bf
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds_from_types.rs
@@ -0,0 +1,51 @@
+#![feature(type_alias_impl_trait)]
+
+type WithLifetime<T> = impl Equals<SelfType = ()>;
+fn _defining_use<T>() -> WithLifetime<T> {}
+
+trait Convert<'a> {
+    type Witness;
+    fn convert<'b, T: ?Sized>(_proof: &'b Self::Witness, x: &'a T) -> &'b T;
+}
+
+impl<'a> Convert<'a> for () {
+    type Witness = WithLifetime<&'a ()>;
+
+    fn convert<'b, T: ?Sized>(_proof: &'b WithLifetime<&'a ()>, x: &'a T) -> &'b T {
+        // compiler used to think it gets to assume 'a: 'b here because
+        // of the `&'b WithLifetime<&'a ()>` argument
+        x
+        //~^ ERROR lifetime may not live long enough
+    }
+}
+
+fn extend_lifetime<'a, 'b, T: ?Sized>(x: &'a T) -> &'b T {
+    WithLifetime::<&'a ()>::convert_helper::<(), T>(&(), x)
+}
+
+trait Equals {
+    type SelfType;
+    fn convert_helper<'a, 'b, W: Convert<'a, Witness = Self>, T: ?Sized>(
+        proof: &'b Self::SelfType,
+        x: &'a T,
+    ) -> &'b T;
+}
+
+impl<S> Equals for S {
+    type SelfType = Self;
+    fn convert_helper<'a, 'b, W: Convert<'a, Witness = Self>, T: ?Sized>(
+        proof: &'b Self,
+        x: &'a T,
+    ) -> &'b T {
+        W::convert(proof, x)
+    }
+}
+
+fn main() {
+    let r;
+    {
+        let x = String::from("Hello World?");
+        r = extend_lifetime(&x);
+    }
+    println!("{}", r);
+}
diff --git a/src/test/ui/type-alias-impl-trait/implied_bounds_from_types.stderr b/src/test/ui/type-alias-impl-trait/implied_bounds_from_types.stderr
new file mode 100644
index 000000000000..cbc5e6073181
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_bounds_from_types.stderr
@@ -0,0 +1,16 @@
+error: lifetime may not live long enough
+  --> $DIR/implied_bounds_from_types.rs:17:9
+   |
+LL | impl<'a> Convert<'a> for () {
+   |      -- lifetime `'a` defined here
+...
+LL |     fn convert<'b, T: ?Sized>(_proof: &'b WithLifetime<&'a ()>, x: &'a T) -> &'b T {
+   |                -- lifetime `'b` defined here
+...
+LL |         x
+   |         ^ associated function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
+   |
+   = help: consider adding the following bound: `'a: 'b`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check.rs b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check.rs
new file mode 100644
index 000000000000..b6a7264a529f
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check.rs
@@ -0,0 +1,27 @@
+#![feature(type_alias_impl_trait)]
+
+// known-bug: #99840
+// this should not compile
+// check-pass
+
+type Alias = impl Sized;
+
+fn constrain() -> Alias {
+    1i32
+}
+
+trait HideIt {
+    type Assoc;
+}
+
+impl HideIt for () {
+    type Assoc = Alias;
+}
+
+pub trait Yay {}
+
+impl Yay for <() as HideIt>::Assoc {}
+// impl Yay for i32 {} // this already errors
+// impl Yay for u32 {} // this also already errors
+
+fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check3.rs b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check3.rs
new file mode 100644
index 000000000000..6e5b8f491eab
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check3.rs
@@ -0,0 +1,43 @@
+#![feature(type_alias_impl_trait)]
+
+mod test_lifetime_param {
+    type Ty<'a> = impl Sized;
+    fn defining(a: &str) -> Ty<'_> { a }
+    fn assert_static<'a: 'static>() {}
+    //~^ WARN: unnecessary lifetime parameter `'a`
+    fn test<'a>() where Ty<'a>: 'static { assert_static::<'a>() }
+    //~^ ERROR: lifetime may not live long enough
+}
+
+mod test_higher_kinded_lifetime_param {
+    type Ty<'a> = impl Sized;
+    fn defining(a: &str) -> Ty<'_> { a }
+    fn assert_static<'a: 'static>() {}
+    //~^ WARN: unnecessary lifetime parameter `'a`
+    fn test<'a>() where for<'b> Ty<'b>: 'a { assert_static::<'a>() }
+    //~^ ERROR: lifetime may not live long enough
+}
+
+mod test_higher_kinded_lifetime_param2 {
+    fn assert_static<'a: 'static>() {}
+    //~^ WARN: unnecessary lifetime parameter `'a`
+    fn test<'a>() { assert_static::<'a>() }
+    //~^ ERROR: lifetime may not live long enough
+}
+
+mod test_type_param {
+    type Ty<A> = impl Sized;
+    fn defining<A>(s: A) -> Ty<A> { s }
+    fn assert_static<A: 'static>() {}
+    fn test<A>() where Ty<A>: 'static { assert_static::<A>() }
+    //~^ ERROR: parameter type `A` may not live long enough
+}
+
+mod test_implied_from_fn_sig {
+    type Opaque<T: 'static> = impl Sized;
+    fn defining<T: 'static>() -> Opaque<T> {}
+    fn assert_static<T: 'static>() {}
+    fn test<T>(_: Opaque<T>) { assert_static::<T>(); }
+}
+
+fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check3.stderr b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check3.stderr
new file mode 100644
index 000000000000..887620a4d50e
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check3.stderr
@@ -0,0 +1,58 @@
+warning: unnecessary lifetime parameter `'a`
+  --> $DIR/implied_lifetime_wf_check3.rs:6:22
+   |
+LL |     fn assert_static<'a: 'static>() {}
+   |                      ^^
+   |
+   = help: you can use the `'static` lifetime directly, in place of `'a`
+
+warning: unnecessary lifetime parameter `'a`
+  --> $DIR/implied_lifetime_wf_check3.rs:15:22
+   |
+LL |     fn assert_static<'a: 'static>() {}
+   |                      ^^
+   |
+   = help: you can use the `'static` lifetime directly, in place of `'a`
+
+warning: unnecessary lifetime parameter `'a`
+  --> $DIR/implied_lifetime_wf_check3.rs:22:22
+   |
+LL |     fn assert_static<'a: 'static>() {}
+   |                      ^^
+   |
+   = help: you can use the `'static` lifetime directly, in place of `'a`
+
+error: lifetime may not live long enough
+  --> $DIR/implied_lifetime_wf_check3.rs:8:43
+   |
+LL |     fn test<'a>() where Ty<'a>: 'static { assert_static::<'a>() }
+   |             -- lifetime `'a` defined here ^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/implied_lifetime_wf_check3.rs:17:46
+   |
+LL |     fn test<'a>() where for<'b> Ty<'b>: 'a { assert_static::<'a>() }
+   |             -- lifetime `'a` defined here    ^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/implied_lifetime_wf_check3.rs:24:21
+   |
+LL |     fn test<'a>() { assert_static::<'a>() }
+   |             --      ^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+   |             |
+   |             lifetime `'a` defined here
+
+error[E0310]: the parameter type `A` may not live long enough
+  --> $DIR/implied_lifetime_wf_check3.rs:32:41
+   |
+LL |     fn test<A>() where Ty<A>: 'static { assert_static::<A>() }
+   |                                         ^^^^^^^^^^^^^^^^^^ ...so that the type `A` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     fn test<A: 'static>() where Ty<A>: 'static { assert_static::<A>() }
+   |              +++++++++
+
+error: aborting due to 4 previous errors; 3 warnings emitted
+
+For more information about this error, try `rustc --explain E0310`.
diff --git a/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check4_static.rs b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check4_static.rs
new file mode 100644
index 000000000000..ac32dbde04b1
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check4_static.rs
@@ -0,0 +1,11 @@
+#![feature(type_alias_impl_trait)]
+
+mod test_type_param_static {
+    type Ty<A> = impl Sized + 'static;
+    //~^ ERROR: the parameter type `A` may not live long enough
+    fn defining<A: 'static>(s: A) -> Ty<A> { s }
+    fn assert_static<A: 'static>() {}
+    fn test<A>() where Ty<A>: 'static { assert_static::<A>() }
+}
+
+fn main() {}
diff --git a/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check4_static.stderr b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check4_static.stderr
new file mode 100644
index 000000000000..47bc31e78c34
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/implied_lifetime_wf_check4_static.stderr
@@ -0,0 +1,14 @@
+error[E0310]: the parameter type `A` may not live long enough
+  --> $DIR/implied_lifetime_wf_check4_static.rs:4:18
+   |
+LL |     type Ty<A> = impl Sized + 'static;
+   |                  ^^^^^^^^^^^^^^^^^^^^ ...so that the type `A` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     type Ty<A: 'static> = impl Sized + 'static;
+   |              +++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0310`.
diff --git a/src/test/ui/type-alias-impl-trait/issue-53398-cyclic-types.stderr b/src/test/ui/type-alias-impl-trait/issue-53398-cyclic-types.stderr
index d20b1cc6d851..0a34e8486a55 100644
--- a/src/test/ui/type-alias-impl-trait/issue-53398-cyclic-types.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-53398-cyclic-types.stderr
@@ -1,10 +1,11 @@
-error[E0275]: overflow evaluating the requirement `fn() -> Foo {foo}: Sized`
+error[E0275]: overflow evaluating the requirement `Foo: Sized`
   --> $DIR/issue-53398-cyclic-types.rs:5:13
    |
 LL | fn foo() -> Foo {
    |             ^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_53398_cyclic_types`)
+   = note: required because it appears within the type `fn() -> Foo {foo}`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.stderr b/src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.stderr
index f14bf6b0f7f5..6344f114a913 100644
--- a/src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-57611-trait-alias.stderr
@@ -4,7 +4,7 @@ error[E0308]: mismatched types
 LL |         |x| x
    |         ^^^^^ one type is more general than the other
    |
-   = note: expected trait `for<'r> Fn<(&'r X,)>`
+   = note: expected trait `for<'a> Fn<(&'a X,)>`
               found trait `Fn<(&X,)>`
 note: this closure does not fulfill the lifetime requirements
   --> $DIR/issue-57611-trait-alias.rs:21:9
diff --git a/src/test/ui/type-alias-impl-trait/issue-58662-generator-with-lifetime.rs b/src/test/ui/type-alias-impl-trait/issue-58662-generator-with-lifetime.rs
index f20ddf020718..477b61390ed4 100644
--- a/src/test/ui/type-alias-impl-trait/issue-58662-generator-with-lifetime.rs
+++ b/src/test/ui/type-alias-impl-trait/issue-58662-generator-with-lifetime.rs
@@ -16,7 +16,7 @@ fn rand_generator<'a>(rng: &'a ()) -> RandGenerator<'a> {
     }
 }
 
-pub type RandGeneratorWithIndirection<'a> = impl Generator<Return = (), Yield = u64> + 'a;
+pub type RandGeneratorWithIndirection<'c> = impl Generator<Return = (), Yield = u64> + 'c;
 pub fn rand_generator_with_indirection<'a>(rng: &'a ()) -> RandGeneratorWithIndirection<'a> {
     fn helper<'b>(rng: &'b ()) -> impl 'b + Generator<Return = (), Yield = u64> {
         move || {
diff --git a/src/test/ui/type-alias-impl-trait/issue-58662-simplified.rs b/src/test/ui/type-alias-impl-trait/issue-58662-simplified.rs
new file mode 100644
index 000000000000..27ca7d0fdc9f
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/issue-58662-simplified.rs
@@ -0,0 +1,20 @@
+// check-pass
+
+#![feature(generators, generator_trait)]
+#![feature(type_alias_impl_trait)]
+
+trait Trait {}
+
+impl<T> Trait for T {}
+
+type Foo<'c> = impl Trait + 'c;
+fn foo<'a>(rng: &'a ()) -> Foo<'a> {
+    fn helper<'b>(rng: &'b ()) -> impl 'b + Trait {
+        rng
+    }
+
+    helper(rng)
+}
+
+fn main() {
+}
diff --git a/src/test/ui/type-alias-impl-trait/issue-60371.stderr b/src/test/ui/type-alias-impl-trait/issue-60371.stderr
index 082b0f0c3097..d0c04371bd79 100644
--- a/src/test/ui/type-alias-impl-trait/issue-60371.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-60371.stderr
@@ -11,7 +11,7 @@ error[E0277]: the trait bound `(): Bug` is not satisfied
   --> $DIR/issue-60371.rs:10:40
    |
 LL |     const FUN: fn() -> Self::Item = || ();
-   |                                        ^ the trait `Bug` is not implemented for `()`
+   |                                        ^^ the trait `Bug` is not implemented for `()`
    |
    = help: the trait `Bug` is implemented for `&()`
 
diff --git a/src/test/ui/type-alias-impl-trait/issue-90400-1.rs b/src/test/ui/type-alias-impl-trait/issue-90400-1.rs
index 8550a3e86379..15aead2f6411 100644
--- a/src/test/ui/type-alias-impl-trait/issue-90400-1.rs
+++ b/src/test/ui/type-alias-impl-trait/issue-90400-1.rs
@@ -1,7 +1,6 @@
 // Regression test for #90400,
 // taken from https://github.com/rust-lang/rust/issues/90400#issuecomment-954927836
 
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 trait Bar {
diff --git a/src/test/ui/type-alias-impl-trait/issue-90400-1.stderr b/src/test/ui/type-alias-impl-trait/issue-90400-1.stderr
index 428a1074031e..ead28769f066 100644
--- a/src/test/ui/type-alias-impl-trait/issue-90400-1.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-90400-1.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `B: Bar` is not satisfied
-  --> $DIR/issue-90400-1.rs:23:9
+  --> $DIR/issue-90400-1.rs:22:9
    |
 LL |         move || bar.bar()
    |         ^^^^^^^^^^^^^^^^^ the trait `Bar` is not implemented for `B`
    |
 note: required by a bound in `<MyFoo as Foo>::foo`
-  --> $DIR/issue-90400-1.rs:22:15
+  --> $DIR/issue-90400-1.rs:21:15
    |
 LL |     fn foo<B: Bar>(&self, bar: B) -> Self::FooFn<B> {
    |               ^^^ required by this bound in `<MyFoo as Foo>::foo`
diff --git a/src/test/ui/type-alias-impl-trait/issue-90400-2.rs b/src/test/ui/type-alias-impl-trait/issue-90400-2.rs
index 2b369bb8a2b9..4c6e893c1729 100644
--- a/src/test/ui/type-alias-impl-trait/issue-90400-2.rs
+++ b/src/test/ui/type-alias-impl-trait/issue-90400-2.rs
@@ -1,7 +1,6 @@
 // Regression test for #90400,
 // taken from https://github.com/rust-lang/rust/issues/90400#issuecomment-954927836
 
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 trait Bar {
diff --git a/src/test/ui/type-alias-impl-trait/issue-90400-2.stderr b/src/test/ui/type-alias-impl-trait/issue-90400-2.stderr
index f84ec0cdc273..50b2dc0495d7 100644
--- a/src/test/ui/type-alias-impl-trait/issue-90400-2.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-90400-2.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `B: Bar` is not satisfied
-  --> $DIR/issue-90400-2.rs:26:9
+  --> $DIR/issue-90400-2.rs:25:9
    |
 LL |         MyBaz(bar)
    |         ^^^^^^^^^^ the trait `Bar` is not implemented for `B`
    |
 note: required for `MyBaz<B>` to implement `Baz`
-  --> $DIR/issue-90400-2.rs:31:14
+  --> $DIR/issue-90400-2.rs:30:14
    |
 LL | impl<B: Bar> Baz for MyBaz<B> {
    |              ^^^     ^^^^^^^^
diff --git a/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-mismatch.rs b/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-mismatch.rs
new file mode 100644
index 000000000000..825710851b01
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-mismatch.rs
@@ -0,0 +1,10 @@
+#![feature(type_alias_impl_trait)]
+
+fn main() {
+    type T = impl Copy;
+    let foo: T = Some((1u32, 2u32));
+    match foo {
+        None => (),
+        Some((a, b, c)) => (), //~ ERROR mismatched types
+    }
+}
diff --git a/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-mismatch.stderr b/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-mismatch.stderr
new file mode 100644
index 000000000000..728244a1844d
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained-mismatch.stderr
@@ -0,0 +1,15 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-96572-unconstrained-mismatch.rs:8:14
+   |
+LL |     match foo {
+   |           --- this expression has type `T`
+LL |         None => (),
+LL |         Some((a, b, c)) => (),
+   |              ^^^^^^^^^ expected a tuple with 2 elements, found one with 3 elements
+   |
+   = note: expected tuple `(u32, u32)`
+              found tuple `(_, _, _)`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained.rs b/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained.rs
new file mode 100644
index 000000000000..2c740ccc1aed
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/issue-96572-unconstrained.rs
@@ -0,0 +1,92 @@
+#![feature(type_alias_impl_trait)]
+// check-pass
+
+fn main() {
+    type T = impl Copy;
+    let foo: T = Some((1u32, 2u32));
+    match foo {
+        None => (),
+        Some((a, b)) => (),
+    }
+}
+
+fn upvar() {
+    #[derive(Copy, Clone)]
+    struct Foo((u32, u32));
+
+    type T = impl Copy;
+    let foo: T = Foo((1u32, 2u32));
+    let x = move || {
+        let Foo((a, b)) = foo;
+    };
+}
+
+fn enum_upvar() {
+    type T = impl Copy;
+    let foo: T = Some((1u32, 2u32));
+    let x = move || {
+        match foo {
+            None => (),
+            Some((a, b)) => (),
+        }
+    };
+}
+
+fn r#struct() {
+    #[derive(Copy, Clone)]
+    struct Foo((u32, u32));
+
+    type U = impl Copy;
+    let foo: U = Foo((1u32, 2u32));
+    let Foo((a, b)) = foo;
+}
+
+mod only_pattern {
+    type T = impl Copy;
+
+    fn foo(foo: T) {
+        let (mut x, mut y) = foo;
+        x = 42;
+        y = "foo";
+    }
+
+    type U = impl Copy;
+
+    fn bar(bar: Option<U>) {
+        match bar {
+            Some((mut x, mut y)) => {
+                x = 42;
+                y = "foo";
+            }
+            None => {}
+        }
+    }
+}
+
+mod only_pattern_rpit {
+    #[allow(unconditional_recursion)]
+    fn foo(b: bool) -> impl Copy {
+        let (mut x, mut y) = foo(false);
+        x = 42;
+        y = "foo";
+        if b {
+            panic!()
+        } else {
+            foo(true)
+        }
+    }
+
+    fn bar(b: bool) -> Option<impl Copy> {
+        if b {
+            return None;
+        }
+        match bar(!b) {
+            Some((mut x, mut y)) => {
+                x = 42;
+                y = "foo";
+            }
+            None => {}
+        }
+        None
+    }
+}
diff --git a/src/test/ui/type-alias-impl-trait/unbounded_opaque_type.rs b/src/test/ui/type-alias-impl-trait/unbounded_opaque_type.rs
new file mode 100644
index 000000000000..f43ad7dce1d4
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/unbounded_opaque_type.rs
@@ -0,0 +1,14 @@
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+type Opaque<T> = impl Sized;
+fn defining<T>() -> Opaque<T> {}
+struct Ss<'a, T>(&'a Opaque<T>);
+
+
+fn test<'a, T>(_: Ss<'a, T>) {
+    // test that we have an implied bound `Opaque<T>: 'a` from fn signature
+    None::<&'a Opaque<T>>;
+}
+
+fn main() {}
diff --git a/src/test/ui/type/type-alias-bounds.rs b/src/test/ui/type/type-alias-bounds.rs
index 65b79650d4d7..e49731725d51 100644
--- a/src/test/ui/type/type-alias-bounds.rs
+++ b/src/test/ui/type/type-alias-bounds.rs
@@ -52,7 +52,7 @@ type T2<U> where U: Bound = U::Assoc;  //~ WARN not enforced in type aliases
 // Do this instead:
 type T4<U> = <U as Bound>::Assoc;
 
-// Make sure the help about associatd types is not shown incorrectly
+// Make sure the help about associated types is not shown incorrectly
 type T5<U: Bound> = <U as Bound>::Assoc;  //~ WARN not enforced in type aliases
 type T6<U: Bound> = ::std::vec::Vec<U>;  //~ WARN not enforced in type aliases
 
diff --git a/src/test/ui/type/type-ascription-instead-of-initializer.stderr b/src/test/ui/type/type-ascription-instead-of-initializer.stderr
index fcac6c495c4b..de578ca93ed5 100644
--- a/src/test/ui/type/type-ascription-instead-of-initializer.stderr
+++ b/src/test/ui/type/type-ascription-instead-of-initializer.stderr
@@ -21,7 +21,7 @@ LL |     pub fn with_capacity(capacity: usize) -> Self {
 help: remove the extra argument
    |
 LL |     let x: Vec::with_capacity(10);
-   |            ~~~~~~~~~~~~~~~~~~~~~~
+   |                              ~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/type/type-mismatch-same-crate-name.stderr b/src/test/ui/type/type-mismatch-same-crate-name.stderr
index 783f747fa6db..fcafd315ebf5 100644
--- a/src/test/ui/type/type-mismatch-same-crate-name.stderr
+++ b/src/test/ui/type/type-mismatch-same-crate-name.stderr
@@ -6,6 +6,17 @@ LL |         a::try_foo(foo2);
    |         |
    |         arguments to this function are incorrect
    |
+   = note: struct `main::a::Foo` and struct `main::a::Foo` have similar names, but are actually distinct types
+note: struct `main::a::Foo` is defined in crate `crate_a2`
+  --> $DIR/auxiliary/crate_a2.rs:1:1
+   |
+LL | pub struct Foo;
+   | ^^^^^^^^^^^^^^
+note: struct `main::a::Foo` is defined in crate `crate_a1`
+  --> $DIR/auxiliary/crate_a1.rs:1:1
+   |
+LL | pub struct Foo;
+   | ^^^^^^^^^^^^^^
    = note: perhaps two different versions of crate `crate_a1` are being used?
 note: function defined here
   --> $DIR/auxiliary/crate_a1.rs:10:8
diff --git a/src/test/ui/typeck/assign-non-lval-derefmut.stderr b/src/test/ui/typeck/assign-non-lval-derefmut.stderr
index a6fcdfe21f48..e394cf8206ed 100644
--- a/src/test/ui/typeck/assign-non-lval-derefmut.stderr
+++ b/src/test/ui/typeck/assign-non-lval-derefmut.stderr
@@ -19,7 +19,7 @@ LL |     x.lock().unwrap() += 1;
    |     |
    |     cannot use `+=` on type `MutexGuard<'_, usize>`
    |
-help: `+=` can be used on `usize`, you can dereference `x.lock().unwrap()`
+help: `+=` can be used on `usize` if you dereference the left-hand side
    |
 LL |     *x.lock().unwrap() += 1;
    |     +
@@ -47,7 +47,7 @@ LL |     y += 1;
    |     |
    |     cannot use `+=` on type `MutexGuard<'_, usize>`
    |
-help: `+=` can be used on `usize`, you can dereference `y`
+help: `+=` can be used on `usize` if you dereference the left-hand side
    |
 LL |     *y += 1;
    |     +
diff --git a/src/test/ui/typeck/assign-non-lval-mut-ref.stderr b/src/test/ui/typeck/assign-non-lval-mut-ref.stderr
index be2e9fe95e87..cbdc960baab8 100644
--- a/src/test/ui/typeck/assign-non-lval-mut-ref.stderr
+++ b/src/test/ui/typeck/assign-non-lval-mut-ref.stderr
@@ -19,7 +19,7 @@ LL |     x.last_mut().unwrap() += 1;
    |     |
    |     cannot use `+=` on type `&mut usize`
    |
-help: `+=` can be used on `usize`, you can dereference `x.last_mut().unwrap()`
+help: `+=` can be used on `usize` if you dereference the left-hand side
    |
 LL |     *x.last_mut().unwrap() += 1;
    |     +
@@ -45,7 +45,7 @@ LL |     y += 1;
    |     |
    |     cannot use `+=` on type `&mut usize`
    |
-help: `+=` can be used on `usize`, you can dereference `y`
+help: `+=` can be used on `usize` if you dereference the left-hand side
    |
 LL |     *y += 1;
    |     +
diff --git a/src/test/ui/typeck/assign-non-lval-needs-deref.rs b/src/test/ui/typeck/assign-non-lval-needs-deref.rs
new file mode 100644
index 000000000000..c979d76b4f41
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-needs-deref.rs
@@ -0,0 +1,19 @@
+// issue #101376
+
+use std::ops::AddAssign;
+struct Foo;
+
+impl AddAssign<()> for Foo {
+    fn add_assign(&mut self, _: ()) {}
+}
+
+impl AddAssign<()> for &mut Foo {
+    fn add_assign(&mut self, _: ()) {}
+}
+
+fn main() {
+    (&mut Foo) += ();
+    //~^ ERROR invalid left-hand side of assignment
+    //~| NOTE cannot assign to this expression
+    //~| HELP consider dereferencing the left-hand side of this operation
+}
diff --git a/src/test/ui/typeck/assign-non-lval-needs-deref.stderr b/src/test/ui/typeck/assign-non-lval-needs-deref.stderr
new file mode 100644
index 000000000000..ee83b1453213
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-needs-deref.stderr
@@ -0,0 +1,16 @@
+error[E0067]: invalid left-hand side of assignment
+  --> $DIR/assign-non-lval-needs-deref.rs:15:16
+   |
+LL |     (&mut Foo) += ();
+   |     ---------- ^^
+   |     |
+   |     cannot assign to this expression
+   |
+help: consider dereferencing the left-hand side of this operation
+   |
+LL |     *(&mut Foo) += ();
+   |     +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0067`.
diff --git a/src/test/ui/typeck/do-not-suggest-placeholder-to-const-static-without-type.rs b/src/test/ui/typeck/do-not-suggest-placeholder-to-const-static-without-type.rs
new file mode 100644
index 000000000000..97e0b213f2e7
--- /dev/null
+++ b/src/test/ui/typeck/do-not-suggest-placeholder-to-const-static-without-type.rs
@@ -0,0 +1,8 @@
+trait Foo {
+    const A; //~ ERROR missing type for `const` item
+    static B;
+    //~^ ERROR associated `static` items are not allowed
+    //~| ERROR missing type for `static` item
+}
+
+fn main() {}
diff --git a/src/test/ui/typeck/do-not-suggest-placeholder-to-const-static-without-type.stderr b/src/test/ui/typeck/do-not-suggest-placeholder-to-const-static-without-type.stderr
new file mode 100644
index 000000000000..8982d6285617
--- /dev/null
+++ b/src/test/ui/typeck/do-not-suggest-placeholder-to-const-static-without-type.stderr
@@ -0,0 +1,20 @@
+error: associated `static` items are not allowed
+  --> $DIR/do-not-suggest-placeholder-to-const-static-without-type.rs:3:5
+   |
+LL |     static B;
+   |     ^^^^^^^^^
+
+error: missing type for `const` item
+  --> $DIR/do-not-suggest-placeholder-to-const-static-without-type.rs:2:12
+   |
+LL |     const A;
+   |            ^ help: provide a type for the item: `: <type>`
+
+error: missing type for `static` item
+  --> $DIR/do-not-suggest-placeholder-to-const-static-without-type.rs:3:13
+   |
+LL |     static B;
+   |             ^ help: provide a type for the item: `: <type>`
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/typeck/point-at-type-param-in-path-expr.rs b/src/test/ui/typeck/point-at-type-param-in-path-expr.rs
new file mode 100644
index 000000000000..9a21536f9b12
--- /dev/null
+++ b/src/test/ui/typeck/point-at-type-param-in-path-expr.rs
@@ -0,0 +1,6 @@
+fn foo<T: std::fmt::Display>() {}
+
+fn main() {
+    let x = foo::<()>;
+    //~^ ERROR `()` doesn't implement `std::fmt::Display`
+}
diff --git a/src/test/ui/typeck/point-at-type-param-in-path-expr.stderr b/src/test/ui/typeck/point-at-type-param-in-path-expr.stderr
new file mode 100644
index 000000000000..1feaa0508bfa
--- /dev/null
+++ b/src/test/ui/typeck/point-at-type-param-in-path-expr.stderr
@@ -0,0 +1,17 @@
+error[E0277]: `()` doesn't implement `std::fmt::Display`
+  --> $DIR/point-at-type-param-in-path-expr.rs:4:19
+   |
+LL |     let x = foo::<()>;
+   |                   ^^ `()` cannot be formatted with the default formatter
+   |
+   = help: the trait `std::fmt::Display` is not implemented for `()`
+   = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
+note: required by a bound in `foo`
+  --> $DIR/point-at-type-param-in-path-expr.rs:1:11
+   |
+LL | fn foo<T: std::fmt::Display>() {}
+   |           ^^^^^^^^^^^^^^^^^ required by this bound in `foo`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/typeck/remove-extra-argument.stderr b/src/test/ui/typeck/remove-extra-argument.stderr
index 703032a83223..b734bcd4eb04 100644
--- a/src/test/ui/typeck/remove-extra-argument.stderr
+++ b/src/test/ui/typeck/remove-extra-argument.stderr
@@ -12,7 +12,7 @@ LL | fn l(_a: Vec<u8>) {}
 help: remove the extra argument
    |
 LL |     l(vec![])
-   |
+   |      ~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/typeck/struct-enum-wrong-args.stderr b/src/test/ui/typeck/struct-enum-wrong-args.stderr
index f72082d53016..ea94bcbc2903 100644
--- a/src/test/ui/typeck/struct-enum-wrong-args.stderr
+++ b/src/test/ui/typeck/struct-enum-wrong-args.stderr
@@ -12,7 +12,7 @@ LL |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: remove the extra argument
    |
 LL |     let _ = Some(3);
-   |             ~~~~~~~
+   |                 ~~~
 
 error[E0061]: this enum variant takes 1 argument but 3 arguments were supplied
   --> $DIR/struct-enum-wrong-args.rs:7:13
@@ -30,7 +30,7 @@ LL |     Ok(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: remove the extra arguments
    |
 LL |     let _ = Ok(3);
-   |             ~~~~~
+   |               ~~~
 
 error[E0061]: this enum variant takes 1 argument but 0 arguments were supplied
   --> $DIR/struct-enum-wrong-args.rs:8:13
@@ -46,7 +46,7 @@ LL |     Ok(#[stable(feature = "rust1", since = "1.0.0")] T),
 help: provide the argument
    |
 LL |     let _ = Ok(/* value */);
-   |             ~~~~~~~~~~~~~~~
+   |               ~~~~~~~~~~~~~
 
 error[E0061]: this struct takes 1 argument but 0 arguments were supplied
   --> $DIR/struct-enum-wrong-args.rs:9:13
@@ -62,7 +62,7 @@ LL | struct Wrapper(i32);
 help: provide the argument
    |
 LL |     let _ = Wrapper(/* i32 */);
-   |             ~~~~~~~~~~~~~~~~~~
+   |                    ~~~~~~~~~~~
 
 error[E0061]: this struct takes 1 argument but 2 arguments were supplied
   --> $DIR/struct-enum-wrong-args.rs:10:13
@@ -78,7 +78,7 @@ LL | struct Wrapper(i32);
 help: remove the extra argument
    |
 LL |     let _ = Wrapper(5);
-   |             ~~~~~~~~~~
+   |                    ~~~
 
 error[E0061]: this struct takes 2 arguments but 0 arguments were supplied
   --> $DIR/struct-enum-wrong-args.rs:11:13
@@ -94,7 +94,7 @@ LL | struct DoubleWrapper(i32, i32);
 help: provide the arguments
    |
 LL |     let _ = DoubleWrapper(/* i32 */, /* i32 */);
-   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                          ~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0061]: this struct takes 2 arguments but 1 argument was supplied
   --> $DIR/struct-enum-wrong-args.rs:12:13
@@ -110,7 +110,7 @@ LL | struct DoubleWrapper(i32, i32);
 help: provide the argument
    |
 LL |     let _ = DoubleWrapper(5, /* i32 */);
-   |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |                          ~~~~~~~~~~~~~~
 
 error[E0061]: this struct takes 2 arguments but 3 arguments were supplied
   --> $DIR/struct-enum-wrong-args.rs:13:13
@@ -126,7 +126,7 @@ LL | struct DoubleWrapper(i32, i32);
 help: remove the extra argument
    |
 LL |     let _ = DoubleWrapper(5, 2);
-   |             ~~~~~~~~~~~~~~~~~~~
+   |                          ~~~~~~
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/typeof/issue-100183.rs b/src/test/ui/typeof/issue-100183.rs
new file mode 100644
index 000000000000..13e9493eaa59
--- /dev/null
+++ b/src/test/ui/typeof/issue-100183.rs
@@ -0,0 +1,6 @@
+struct Struct {
+    y: (typeof("hey"),),
+    //~^ ERROR `typeof` is a reserved keyword but unimplemented
+}
+
+fn main() {}
diff --git a/src/test/ui/typeof/issue-100183.stderr b/src/test/ui/typeof/issue-100183.stderr
new file mode 100644
index 000000000000..01d3079b246d
--- /dev/null
+++ b/src/test/ui/typeof/issue-100183.stderr
@@ -0,0 +1,14 @@
+error[E0516]: `typeof` is a reserved keyword but unimplemented
+  --> $DIR/issue-100183.rs:2:9
+   |
+LL |     y: (typeof("hey"),),
+   |         ^^^^^^^^^^^^^ reserved keyword
+   |
+help: consider replacing `typeof(...)` with an actual type
+   |
+LL |     y: (&'static str,),
+   |         ~~~~~~~~~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0516`.
diff --git a/src/test/ui/ufcs/ufcs-qpath-self-mismatch.rs b/src/test/ui/ufcs/ufcs-qpath-self-mismatch.rs
index 939b3c5223c4..ec86213f8629 100644
--- a/src/test/ui/ufcs/ufcs-qpath-self-mismatch.rs
+++ b/src/test/ui/ufcs/ufcs-qpath-self-mismatch.rs
@@ -3,6 +3,7 @@ use std::ops::Add;
 fn main() {
     <i32 as Add<u32>>::add(1, 2);
     //~^ ERROR cannot add `u32` to `i32`
+    //~| ERROR cannot add `u32` to `i32`
     <i32 as Add<i32>>::add(1u32, 2);
     //~^ ERROR mismatched types
     <i32 as Add<i32>>::add(1, 2u32);
diff --git a/src/test/ui/ufcs/ufcs-qpath-self-mismatch.stderr b/src/test/ui/ufcs/ufcs-qpath-self-mismatch.stderr
index f08c81bc1e93..eaab6ff3d9a0 100644
--- a/src/test/ui/ufcs/ufcs-qpath-self-mismatch.stderr
+++ b/src/test/ui/ufcs/ufcs-qpath-self-mismatch.stderr
@@ -19,7 +19,7 @@ LL |     <i32 as Add<u32>>::add(1, 2);
            and 48 others
 
 error[E0308]: mismatched types
-  --> $DIR/ufcs-qpath-self-mismatch.rs:6:28
+  --> $DIR/ufcs-qpath-self-mismatch.rs:7:28
    |
 LL |     <i32 as Add<i32>>::add(1u32, 2);
    |     ---------------------- ^^^^ expected `i32`, found `u32`
@@ -37,7 +37,7 @@ LL |     <i32 as Add<i32>>::add(1i32, 2);
    |                             ~~~
 
 error[E0308]: mismatched types
-  --> $DIR/ufcs-qpath-self-mismatch.rs:8:31
+  --> $DIR/ufcs-qpath-self-mismatch.rs:9:31
    |
 LL |     <i32 as Add<i32>>::add(1, 2u32);
    |     ----------------------    ^^^^ expected `i32`, found `u32`
@@ -54,7 +54,25 @@ help: change the type of the numeric literal from `u32` to `i32`
 LL |     <i32 as Add<i32>>::add(1, 2i32);
    |                                ~~~
 
-error: aborting due to 3 previous errors
+error[E0277]: cannot add `u32` to `i32`
+  --> $DIR/ufcs-qpath-self-mismatch.rs:4:5
+   |
+LL |     <i32 as Add<u32>>::add(1, 2);
+   |     ^^^^^^^^^^^^^^^^^^^^^^ no implementation for `i32 + u32`
+   |
+   = help: the trait `Add<u32>` is not implemented for `i32`
+   = help: the following other types implement trait `Add<Rhs>`:
+             <&'a f32 as Add<f32>>
+             <&'a f64 as Add<f64>>
+             <&'a i128 as Add<i128>>
+             <&'a i16 as Add<i16>>
+             <&'a i32 as Add<i32>>
+             <&'a i64 as Add<i64>>
+             <&'a i8 as Add<i8>>
+             <&'a isize as Add<isize>>
+           and 48 others
+
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0277, E0308.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr b/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr
index 18e133957ba3..802696e1b2f9 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr
@@ -1,4 +1,4 @@
-error[E0277]: expected a `Fn<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+error[E0277]: expected a `Fn<(&isize,)>` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:20:21
    |
 LL |     let x = call_it(&square, 22);
@@ -6,7 +6,7 @@ LL |     let x = call_it(&square, 22);
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> Fn<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
+   = help: the trait `for<'a> Fn<(&'a isize,)>` is not implemented for fn item `for<'a> unsafe fn(&'a isize) -> isize {square}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `call_it`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:9:15
@@ -14,7 +14,7 @@ note: required by a bound in `call_it`
 LL | fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize {
    |               ^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
 
-error[E0277]: expected a `FnMut<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+error[E0277]: expected a `FnMut<(&isize,)>` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:25:25
    |
 LL |     let y = call_it_mut(&mut square, 22);
@@ -22,7 +22,7 @@ LL |     let y = call_it_mut(&mut square, 22);
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> FnMut<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
+   = help: the trait `for<'a> FnMut<(&'a isize,)>` is not implemented for fn item `for<'a> unsafe fn(&'a isize) -> isize {square}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `call_it_mut`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:12:19
@@ -30,7 +30,7 @@ note: required by a bound in `call_it_mut`
 LL | fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize {
    |                   ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_mut`
 
-error[E0277]: expected a `FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+error[E0277]: expected a `FnOnce<(&isize,)>` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:30:26
    |
 LL |     let z = call_it_once(square, 22);
@@ -38,7 +38,7 @@ LL |     let z = call_it_once(square, 22);
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> FnOnce<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
+   = help: the trait `for<'a> FnOnce<(&'a isize,)>` is not implemented for fn item `for<'a> unsafe fn(&'a isize) -> isize {square}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `call_it_once`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:15:20
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr b/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr
index 77c176de625c..0bbb9836c584 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr
@@ -1,42 +1,42 @@
-error[E0277]: expected a `Fn<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+error[E0277]: expected a `Fn<(&isize,)>` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
   --> $DIR/unboxed-closures-wrong-abi.rs:20:21
    |
 LL |     let x = call_it(&square, 22);
-   |             ------- ^^^^^^^ expected an `Fn<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   |             ------- ^^^^^^^ expected an `Fn<(&isize,)>` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> Fn<(&'r isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   = help: the trait `for<'a> Fn<(&'a isize,)>` is not implemented for fn item `for<'a> extern "C" fn(&'a isize) -> isize {square}`
 note: required by a bound in `call_it`
   --> $DIR/unboxed-closures-wrong-abi.rs:9:15
    |
 LL | fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize {
    |               ^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
 
-error[E0277]: expected a `FnMut<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+error[E0277]: expected a `FnMut<(&isize,)>` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
   --> $DIR/unboxed-closures-wrong-abi.rs:25:25
    |
 LL |     let y = call_it_mut(&mut square, 22);
-   |             ----------- ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   |             ----------- ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> FnMut<(&'r isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   = help: the trait `for<'a> FnMut<(&'a isize,)>` is not implemented for fn item `for<'a> extern "C" fn(&'a isize) -> isize {square}`
 note: required by a bound in `call_it_mut`
   --> $DIR/unboxed-closures-wrong-abi.rs:12:19
    |
 LL | fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize {
    |                   ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_mut`
 
-error[E0277]: expected a `FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+error[E0277]: expected a `FnOnce<(&isize,)>` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
   --> $DIR/unboxed-closures-wrong-abi.rs:30:26
    |
 LL |     let z = call_it_once(square, 22);
-   |             ------------ ^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   |             ------------ ^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> FnOnce<(&'r isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   = help: the trait `for<'a> FnOnce<(&'a isize,)>` is not implemented for fn item `for<'a> extern "C" fn(&'a isize) -> isize {square}`
 note: required by a bound in `call_it_once`
   --> $DIR/unboxed-closures-wrong-abi.rs:15:20
    |
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr b/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr
index c826af3c4c38..31a66790ce08 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr
@@ -6,7 +6,7 @@ LL |     let x = call_it(&square, 22);
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> Fn<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
+   = help: the trait `for<'a> Fn<(&'a isize,)>` is not implemented for fn item `unsafe fn(isize) -> isize {square}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `call_it`
   --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:10:15
@@ -22,7 +22,7 @@ LL |     let y = call_it_mut(&mut square, 22);
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> FnMut<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
+   = help: the trait `for<'a> FnMut<(&'a isize,)>` is not implemented for fn item `unsafe fn(isize) -> isize {square}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `call_it_mut`
   --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:13:19
@@ -38,7 +38,7 @@ LL |     let z = call_it_once(square, 22);
    |             |
    |             required by a bound introduced by this call
    |
-   = help: the trait `for<'r> FnOnce<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
+   = help: the trait `for<'a> FnOnce<(&'a isize,)>` is not implemented for fn item `unsafe fn(isize) -> isize {square}`
    = note: unsafe function cannot be called generically without an unsafe block
 note: required by a bound in `call_it_once`
   --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:16:20
diff --git a/src/test/ui/uninhabited/privately-uninhabited-mir-call.stderr b/src/test/ui/uninhabited/privately-uninhabited-mir-call.stderr
index 95c209f47c92..0dfd22a30acc 100644
--- a/src/test/ui/uninhabited/privately-uninhabited-mir-call.stderr
+++ b/src/test/ui/uninhabited/privately-uninhabited-mir-call.stderr
@@ -6,6 +6,11 @@ LL |     let y: &mut u32;
 ...
 LL |     *y = 2;
    |     ^^^^^^ `y` used here but it isn't initialized
+   |
+help: consider assigning a value
+   |
+LL |     let y: &mut u32 = todo!();
+   |                     +++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/uninhabited/uninhabited-irrefutable.rs b/src/test/ui/uninhabited/uninhabited-irrefutable.rs
index 661b5486adc1..1a0f3c5e5504 100644
--- a/src/test/ui/uninhabited/uninhabited-irrefutable.rs
+++ b/src/test/ui/uninhabited/uninhabited-irrefutable.rs
@@ -24,5 +24,5 @@ enum Foo {
 
 fn main() {
     let x: Foo = Foo::D(123, 456);
-    let Foo::D(_y, _z) = x; //~ ERROR refutable pattern in local binding: `A(_)` not covered
+    let Foo::D(_y, _z) = x; //~ ERROR refutable pattern in local binding: `Foo::A(_)` not covered
 }
diff --git a/src/test/ui/uninhabited/uninhabited-irrefutable.stderr b/src/test/ui/uninhabited/uninhabited-irrefutable.stderr
index c571e17a7b37..32f287a18188 100644
--- a/src/test/ui/uninhabited/uninhabited-irrefutable.stderr
+++ b/src/test/ui/uninhabited/uninhabited-irrefutable.stderr
@@ -1,8 +1,8 @@
-error[E0005]: refutable pattern in local binding: `A(_)` not covered
+error[E0005]: refutable pattern in local binding: `Foo::A(_)` not covered
   --> $DIR/uninhabited-irrefutable.rs:27:9
    |
 LL |     let Foo::D(_y, _z) = x;
-   |         ^^^^^^^^^^^^^^ pattern `A(_)` not covered
+   |         ^^^^^^^^^^^^^^ pattern `Foo::A(_)` not covered
    |
    = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
    = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
@@ -18,7 +18,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let (_y, _z) = if let Foo::D(_y, _z) = x { (_y, _z) } else { todo!() };
    |     +++++++++++++++++                        +++++++++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Foo::D(_y, _z) = x else { todo!() };
    |                            ++++++++++++++++
diff --git a/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr b/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr
index 2c107b1f7a47..c7882963407f 100644
--- a/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr
+++ b/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr
@@ -122,7 +122,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let x = if let Ok(x) = x { x } else { todo!() };
    |     ++++++++++               ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Ok(x) = x else { todo!() };
    |                   ++++++++++++++++
diff --git a/src/test/ui/union/union-copy.stderr b/src/test/ui/union/union-copy.stderr
index 8ecdafdde204..53ee4dd2e5bd 100644
--- a/src/test/ui/union/union-copy.stderr
+++ b/src/test/ui/union/union-copy.stderr
@@ -1,11 +1,11 @@
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/union-copy.rs:12:6
+  --> $DIR/union-copy.rs:12:15
    |
 LL |     a: std::mem::ManuallyDrop<String>
    |     --------------------------------- this field does not implement `Copy`
 ...
 LL | impl Copy for W {}
-   |      ^^^^
+   |               ^
    |
 note: the `Copy` impl for `ManuallyDrop<String>` requires that `String: Copy`
   --> $DIR/union-copy.rs:8:8
diff --git a/src/test/ui/unpretty/avoid-crash.rs b/src/test/ui/unpretty/avoid-crash.rs
new file mode 100644
index 000000000000..fd84b70d944c
--- /dev/null
+++ b/src/test/ui/unpretty/avoid-crash.rs
@@ -0,0 +1,4 @@
+// normalize-stderr-test "error `.*`" -> "$$ERROR_MESSAGE"
+// compile-flags: -o/tmp/ -Zunpretty=ast-tree
+
+fn main() {}
diff --git a/src/test/ui/unpretty/avoid-crash.stderr b/src/test/ui/unpretty/avoid-crash.stderr
new file mode 100644
index 000000000000..11cd3866fa86
--- /dev/null
+++ b/src/test/ui/unpretty/avoid-crash.stderr
@@ -0,0 +1,4 @@
+error: pretty-print failed to write `/tmp/` due to $ERROR_MESSAGE
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/unpretty/pretty-let-else.rs b/src/test/ui/unpretty/pretty-let-else.rs
index 5abfa2523b74..b5ae529699da 100644
--- a/src/test/ui/unpretty/pretty-let-else.rs
+++ b/src/test/ui/unpretty/pretty-let-else.rs
@@ -1,7 +1,7 @@
 // compile-flags: -Zunpretty=hir
 // check-pass
 
-#![feature(let_else)]
+
 
 fn foo(x: Option<u32>) {
     let Some(_) = x else { panic!() };
diff --git a/src/test/ui/unpretty/pretty-let-else.stdout b/src/test/ui/unpretty/pretty-let-else.stdout
index ffe1d1657aa1..35ad1cd1b181 100644
--- a/src/test/ui/unpretty/pretty-let-else.stdout
+++ b/src/test/ui/unpretty/pretty-let-else.stdout
@@ -1,11 +1,11 @@
-// compile-flags: -Zunpretty=hir
-// check-pass
-
-#![feature(let_else)]
 #[prelude_import]
 use ::std::prelude::rust_2015::*;
 #[macro_use]
 extern crate std;
+// compile-flags: -Zunpretty=hir
+// check-pass
+
+
 
 fn foo(x:
         Option<u32>) {
diff --git a/src/test/ui/unsized/issue-30355.stderr b/src/test/ui/unsized/issue-30355.stderr
index f5491552a45d..71bbdf5dec76 100644
--- a/src/test/ui/unsized/issue-30355.stderr
+++ b/src/test/ui/unsized/issue-30355.stderr
@@ -5,11 +5,8 @@ LL |     &X(*Y)
    |        ^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `[u8]`
+   = note: all function arguments must have a statically known size
    = help: unsized fn params are gated as an unstable feature
-help: function arguments must have a statically known size, borrowed types always have a known size
-   |
-LL |     &X(&*Y)
-   |        +
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/unsized/issue-75899-but-gats.rs b/src/test/ui/unsized/issue-75899-but-gats.rs
new file mode 100644
index 000000000000..5716817f43de
--- /dev/null
+++ b/src/test/ui/unsized/issue-75899-but-gats.rs
@@ -0,0 +1,21 @@
+// check-pass
+
+use std::fmt::Debug;
+use std::marker::PhantomData;
+
+trait Foo {
+    type Gat<'a>: ?Sized where Self: 'a;
+}
+
+struct Bar<'a, T: Foo + 'a>(T::Gat<'a>);
+
+struct Baz<T: ?Sized>(PhantomData<T>);
+
+impl<T: ?Sized> Foo for Baz<T> {
+    type Gat<'a> = T where Self: 'a;
+}
+
+fn main() {
+    let x = Bar::<'_, Baz<()>>(());
+    let y: &Bar<'_, Baz<dyn Debug>> = &x;
+}
diff --git a/src/test/ui/unsized/issue-75899.rs b/src/test/ui/unsized/issue-75899.rs
new file mode 100644
index 000000000000..abff17e11b54
--- /dev/null
+++ b/src/test/ui/unsized/issue-75899.rs
@@ -0,0 +1,18 @@
+// check-pass
+
+trait Trait {}
+impl<T> Trait for T {}
+
+trait Noop {
+    type Assoc: ?Sized;
+}
+impl<T: ?Sized> Noop for T {
+    type Assoc = T;
+}
+
+struct NoopNewtype<T: ?Sized + Noop>(T::Assoc);
+fn coerce_newtype<T: Trait>(x: &NoopNewtype<T>) -> &NoopNewtype<dyn Trait + '_> {
+    x
+}
+
+fn main() {}
diff --git a/src/test/ui/unwind-abis/ffi-unwind-calls-lint.rs b/src/test/ui/unwind-abis/ffi-unwind-calls-lint.rs
index dadf4b121878..9a324f00435c 100644
--- a/src/test/ui/unwind-abis/ffi-unwind-calls-lint.rs
+++ b/src/test/ui/unwind-abis/ffi-unwind-calls-lint.rs
@@ -1,6 +1,5 @@
 // build-pass
 // needs-unwind
-// ignore-wasm32-bare compiled with panic=abort by default
 
 #![feature(c_unwind)]
 #![warn(ffi_unwind_calls)]
diff --git a/src/test/ui/unwind-abis/ffi-unwind-calls-lint.stderr b/src/test/ui/unwind-abis/ffi-unwind-calls-lint.stderr
index ed41cb74623c..937a2b3dff8b 100644
--- a/src/test/ui/unwind-abis/ffi-unwind-calls-lint.stderr
+++ b/src/test/ui/unwind-abis/ffi-unwind-calls-lint.stderr
@@ -1,17 +1,17 @@
 warning: call to foreign function with FFI-unwind ABI
-  --> $DIR/ffi-unwind-calls-lint.rs:21:14
+  --> $DIR/ffi-unwind-calls-lint.rs:20:14
    |
 LL |     unsafe { foo(); }
    |              ^^^^^ call to foreign function with FFI-unwind ABI
    |
 note: the lint level is defined here
-  --> $DIR/ffi-unwind-calls-lint.rs:6:9
+  --> $DIR/ffi-unwind-calls-lint.rs:5:9
    |
 LL | #![warn(ffi_unwind_calls)]
    |         ^^^^^^^^^^^^^^^^
 
 warning: call to function pointer with FFI-unwind ABI
-  --> $DIR/ffi-unwind-calls-lint.rs:25:5
+  --> $DIR/ffi-unwind-calls-lint.rs:24:5
    |
 LL |     ptr();
    |     ^^^^^ call to function pointer with FFI-unwind ABI
diff --git a/src/test/ui/unwind-no-uwtable.rs b/src/test/ui/unwind-no-uwtable.rs
index 0440cf488e8b..3bc309233a7a 100644
--- a/src/test/ui/unwind-no-uwtable.rs
+++ b/src/test/ui/unwind-no-uwtable.rs
@@ -1,7 +1,6 @@
 // run-pass
 // needs-unwind
 // ignore-windows target requires uwtable
-// ignore-wasm32-bare no proper panic=unwind support
 // compile-flags: -C panic=unwind -C force-unwind-tables=n
 
 use std::panic::{self, AssertUnwindSafe};
diff --git a/src/test/ui/variance/variance-use-contravariant-struct-1.rs b/src/test/ui/variance/variance-use-contravariant-struct-1.rs
index 7f59067483b9..40781fbf082b 100644
--- a/src/test/ui/variance/variance-use-contravariant-struct-1.rs
+++ b/src/test/ui/variance/variance-use-contravariant-struct-1.rs
@@ -1,4 +1,4 @@
-// Test various uses of structs with distint variances to make sure
+// Test various uses of structs with distinct variances to make sure
 // they permit lifetimes to be approximated as expected.
 
 struct SomeStruct<T>(fn(T));
diff --git a/src/test/ui/variance/variance-use-contravariant-struct-2.rs b/src/test/ui/variance/variance-use-contravariant-struct-2.rs
index 2113eb2addb9..d4b2d08342a9 100644
--- a/src/test/ui/variance/variance-use-contravariant-struct-2.rs
+++ b/src/test/ui/variance/variance-use-contravariant-struct-2.rs
@@ -1,4 +1,4 @@
-// Test various uses of structs with distint variances to make sure
+// Test various uses of structs with distinct variances to make sure
 // they permit lifetimes to be approximated as expected.
 
 #![allow(dead_code)]
diff --git a/src/test/ui/variance/variance-use-invariant-struct-1.rs b/src/test/ui/variance/variance-use-invariant-struct-1.rs
index d40dbceb5f8c..72f50f3459d1 100644
--- a/src/test/ui/variance/variance-use-invariant-struct-1.rs
+++ b/src/test/ui/variance/variance-use-invariant-struct-1.rs
@@ -1,4 +1,4 @@
-// Test various uses of structs with distint variances to make sure
+// Test various uses of structs with distinct variances to make sure
 // they permit lifetimes to be approximated as expected.
 
 struct SomeStruct<T>(*mut T);
diff --git a/src/test/ui/wait-forked-but-failed-child.rs b/src/test/ui/wait-forked-but-failed-child.rs
index 0eb0fe071f50..674c26a43f20 100644
--- a/src/test/ui/wait-forked-but-failed-child.rs
+++ b/src/test/ui/wait-forked-but-failed-child.rs
@@ -2,6 +2,7 @@
 // ignore-emscripten no processes
 // ignore-sgx no processes
 // ignore-vxworks no 'ps'
+// ignore-fuchsia no 'ps'
 
 #![feature(rustc_private)]
 
diff --git a/src/tools/build-manifest/src/main.rs b/src/tools/build-manifest/src/main.rs
index 1a6760d8c68b..14311cff5c8c 100644
--- a/src/tools/build-manifest/src/main.rs
+++ b/src/tools/build-manifest/src/main.rs
@@ -11,9 +11,9 @@ mod versions;
 use crate::checksum::Checksums;
 use crate::manifest::{Component, Manifest, Package, Rename, Target};
 use crate::versions::{PkgType, Versions};
-use std::collections::{BTreeMap, HashMap, HashSet};
+use std::collections::{BTreeMap, HashSet};
 use std::env;
-use std::fs::{self, File};
+use std::fs;
 use std::path::{Path, PathBuf};
 
 static HOSTS: &[&str] = &[
@@ -184,7 +184,7 @@ static PKG_INSTALLERS: &[&str] = &["x86_64-apple-darwin", "aarch64-apple-darwin"
 
 static MINGW: &[&str] = &["i686-pc-windows-gnu", "x86_64-pc-windows-gnu"];
 
-static NIGHTLY_ONLY_COMPONENTS: &[&str] = &["miri-preview"];
+static NIGHTLY_ONLY_COMPONENTS: &[&str] = &["miri-preview", "rust-docs-json-preview"];
 
 macro_rules! t {
     ($e:expr) => {
@@ -239,7 +239,6 @@ fn main() {
 
 impl Builder {
     fn build(&mut self) {
-        self.check_toolstate();
         let manifest = self.build_manifest();
 
         let channel = self.versions.channel().to_string();
@@ -261,29 +260,6 @@ impl Builder {
         t!(self.checksums.store_cache());
     }
 
-    /// If a tool does not pass its tests on *any* of Linux and Windows, don't ship
-    /// it on *all* targets, because tools like Miri can "cross-run" programs for
-    /// different targets, for example, run a program for `x86_64-pc-windows-msvc`
-    /// on `x86_64-unknown-linux-gnu`.
-    /// Right now, we do this only for Miri.
-    fn check_toolstate(&mut self) {
-        for file in &["toolstates-linux.json", "toolstates-windows.json"] {
-            let toolstates: Option<HashMap<String, String>> = File::open(self.input.join(file))
-                .ok()
-                .and_then(|f| serde_json::from_reader(&f).ok());
-            let toolstates = toolstates.unwrap_or_else(|| {
-                println!("WARNING: `{}` missing/malformed; assuming all tools failed", file);
-                HashMap::default() // Use empty map if anything went wrong.
-            });
-            // Mark some tools as missing based on toolstate.
-            if toolstates.get("miri").map(|s| &*s as &str) != Some("test-pass") {
-                println!("Miri tests are not passing, removing component");
-                self.versions.disable_version(&PkgType::Miri);
-                break;
-            }
-        }
-    }
-
     fn build_manifest(&mut self) -> Manifest {
         let mut manifest = Manifest {
             manifest_version: "2".to_string(),
@@ -318,6 +294,7 @@ impl Builder {
         package!("rust-mingw", MINGW);
         package!("rust-std", TARGETS);
         self.package("rust-docs", &mut manifest.pkg, HOSTS, DOCS_FALLBACK);
+        self.package("rust-docs-json-preview", &mut manifest.pkg, HOSTS, DOCS_FALLBACK);
         package!("rust-src", &["*"]);
         package!("rls-preview", HOSTS);
         package!("rust-analyzer-preview", HOSTS);
@@ -403,6 +380,7 @@ impl Builder {
         rename("rustfmt", "rustfmt-preview");
         rename("clippy", "clippy-preview");
         rename("miri", "miri-preview");
+        rename("rust-docs-json", "rust-docs-json-preview");
         rename("rust-analyzer", "rust-analyzer-preview");
     }
 
@@ -459,6 +437,7 @@ impl Builder {
             host_component("rustfmt-preview"),
             host_component("llvm-tools-preview"),
             host_component("rust-analysis"),
+            host_component("rust-docs-json"),
         ]);
 
         extensions.extend(
@@ -543,8 +522,18 @@ impl Builder {
             for (substr, fallback_target) in fallback {
                 if target_name.contains(substr) {
                     let t = Target::from_compressed_tar(self, &tarball_name!(fallback_target));
-                    // Fallbacks must always be available.
-                    assert!(t.available);
+                    // Fallbacks should typically be available on 'production' builds
+                    // but may not be available for try builds, which only build one target by
+                    // default. Ideally we'd gate this being a hard error on whether we're in a
+                    // production build or not, but it's not information that's readily available
+                    // here.
+                    if !t.available {
+                        eprintln!(
+                            "{:?} not available for fallback",
+                            tarball_name!(fallback_target)
+                        );
+                        continue;
+                    }
                     return t;
                 }
             }
diff --git a/src/tools/build-manifest/src/versions.rs b/src/tools/build-manifest/src/versions.rs
index 95c2297de264..92ef9968fe52 100644
--- a/src/tools/build-manifest/src/versions.rs
+++ b/src/tools/build-manifest/src/versions.rs
@@ -157,17 +157,6 @@ impl Versions {
         Ok(VersionInfo { version, git_commit, present: true })
     }
 
-    pub(crate) fn disable_version(&mut self, package: &PkgType) {
-        match self.versions.get_mut(package) {
-            Some(version) => {
-                *version = VersionInfo::default();
-            }
-            None => {
-                self.versions.insert(package.clone(), VersionInfo::default());
-            }
-        }
-    }
-
     pub(crate) fn archive_name(
         &self,
         package: &PkgType,
diff --git a/src/tools/cargo b/src/tools/cargo
index 4ed54cecce3c..73ba3f35e020 160000
--- a/src/tools/cargo
+++ b/src/tools/cargo
@@ -1 +1 @@
-Subproject commit 4ed54cecce3ce9ab6ff058781f4c8a500ee6b8b5
+Subproject commit 73ba3f35e0205844418260722c11602113179c4a
diff --git a/src/tools/clippy/.github/workflows/clippy.yml b/src/tools/clippy/.github/workflows/clippy.yml
index 0e27cc927ace..fac2c99714d9 100644
--- a/src/tools/clippy/.github/workflows/clippy.yml
+++ b/src/tools/clippy/.github/workflows/clippy.yml
@@ -24,6 +24,7 @@ env:
   RUST_BACKTRACE: 1
   CARGO_TARGET_DIR: '${{ github.workspace }}/target'
   NO_FMT_TEST: 1
+  CARGO_INCREMENTAL: 0
 
 jobs:
   base:
diff --git a/src/tools/clippy/.github/workflows/clippy_bors.yml b/src/tools/clippy/.github/workflows/clippy_bors.yml
index 97453303cd6a..30607af49012 100644
--- a/src/tools/clippy/.github/workflows/clippy_bors.yml
+++ b/src/tools/clippy/.github/workflows/clippy_bors.yml
@@ -10,6 +10,7 @@ env:
   RUST_BACKTRACE: 1
   CARGO_TARGET_DIR: '${{ github.workspace }}/target'
   NO_FMT_TEST: 1
+  CARGO_INCREMENTAL: 0
 
 defaults:
   run:
diff --git a/src/tools/clippy/CHANGELOG.md b/src/tools/clippy/CHANGELOG.md
index 380cd451987b..044cbff4b78e 100644
--- a/src/tools/clippy/CHANGELOG.md
+++ b/src/tools/clippy/CHANGELOG.md
@@ -6,11 +6,157 @@ document.
 
 ## Unreleased / In Rust Nightly
 
-[7c21f91b...master](https://github.com/rust-lang/rust-clippy/compare/7c21f91b...master)
+[d7b5cbf0...master](https://github.com/rust-lang/rust-clippy/compare/d7b5cbf0...master)
+
+## Rust 1.63
+
+Current stable, released 2022-08-11
+
+[7c21f91b...d7b5cbf0](https://github.com/rust-lang/rust-clippy/compare/7c21f91b...d7b5cbf0)
+
+### New Lints
+
+* [`borrow_deref_ref`]
+  [#7930](https://github.com/rust-lang/rust-clippy/pull/7930)
+* [`doc_link_with_quotes`]
+  [#8385](https://github.com/rust-lang/rust-clippy/pull/8385)
+* [`no_effect_replace`]
+  [#8754](https://github.com/rust-lang/rust-clippy/pull/8754)
+* [`rc_clone_in_vec_init`]
+  [#8769](https://github.com/rust-lang/rust-clippy/pull/8769)
+* [`derive_partial_eq_without_eq`]
+  [#8796](https://github.com/rust-lang/rust-clippy/pull/8796)
+* [`mismatching_type_param_order`]
+  [#8831](https://github.com/rust-lang/rust-clippy/pull/8831)
+* [`duplicate_mod`] [#8832](https://github.com/rust-lang/rust-clippy/pull/8832)
+* [`unused_rounding`]
+  [#8866](https://github.com/rust-lang/rust-clippy/pull/8866)
+* [`get_first`] [#8882](https://github.com/rust-lang/rust-clippy/pull/8882)
+* [`swap_ptr_to_ref`]
+  [#8916](https://github.com/rust-lang/rust-clippy/pull/8916)
+* [`almost_complete_letter_range`]
+  [#8918](https://github.com/rust-lang/rust-clippy/pull/8918)
+* [`needless_parens_on_range_literals`]
+  [#8933](https://github.com/rust-lang/rust-clippy/pull/8933)
+* [`as_underscore`] [#8934](https://github.com/rust-lang/rust-clippy/pull/8934)
+
+### Moves and Deprecations
+
+* Rename `eval_order_dependence` to [`mixed_read_write_in_expression`], move to
+  `nursery` [#8621](https://github.com/rust-lang/rust-clippy/pull/8621)
+
+### Enhancements
+
+* [`undocumented_unsafe_blocks`]: Now also lints on unsafe trait implementations
+  [#8761](https://github.com/rust-lang/rust-clippy/pull/8761)
+* [`empty_line_after_outer_attr`]: Now also lints on argumentless macros
+  [#8790](https://github.com/rust-lang/rust-clippy/pull/8790)
+* [`expect_used`]: Now can be disabled in tests with the `allow-expect-in-tests`
+  option [#8802](https://github.com/rust-lang/rust-clippy/pull/8802)
+* [`unwrap_used`]: Now can be disabled in tests with the `allow-unwrap-in-tests`
+  option [#8802](https://github.com/rust-lang/rust-clippy/pull/8802)
+* [`disallowed_methods`]: Now also lints indirect usages
+  [#8852](https://github.com/rust-lang/rust-clippy/pull/8852)
+* [`get_last_with_len`]: Now also lints `VecDeque` and any deref to slice
+  [#8862](https://github.com/rust-lang/rust-clippy/pull/8862)
+* [`manual_range_contains`]: Now also lints on chains of `&&` and `||`
+  [#8884](https://github.com/rust-lang/rust-clippy/pull/8884)
+* [`rc_clone_in_vec_init`]: Now also lints on `Weak`
+  [#8885](https://github.com/rust-lang/rust-clippy/pull/8885)
+* [`dbg_macro`]: Introduce `allow-dbg-in-tests` config option
+  [#8897](https://github.com/rust-lang/rust-clippy/pull/8897)
+* [`use_self`]: Now also lints on `TupleStruct` and `Struct` patterns
+  [#8899](https://github.com/rust-lang/rust-clippy/pull/8899)
+* [`manual_find_map`] and [`manual_filter_map`]: Now also lints on more complex
+  method chains inside `map`
+  [#8930](https://github.com/rust-lang/rust-clippy/pull/8930)
+* [`needless_return`]: Now also lints on macro expressions in return statements
+  [#8932](https://github.com/rust-lang/rust-clippy/pull/8932)
+* [`doc_markdown`]: Users can now indicate, that the `doc-valid-idents` config
+  should extend the default and not replace it
+  [#8944](https://github.com/rust-lang/rust-clippy/pull/8944)
+* [`disallowed_names`]: Users can now indicate, that the `disallowed-names`
+  config should extend the default and not replace it
+  [#8944](https://github.com/rust-lang/rust-clippy/pull/8944)
+* [`never_loop`]: Now checks for `continue` in struct expression
+  [#9002](https://github.com/rust-lang/rust-clippy/pull/9002)
+
+### False Positive Fixes
+
+* [`useless_transmute`]: No longer lints on types with erased regions
+  [#8564](https://github.com/rust-lang/rust-clippy/pull/8564)
+* [`vec_init_then_push`]: No longer lints when further extended
+  [#8699](https://github.com/rust-lang/rust-clippy/pull/8699)
+* [`cmp_owned`]: No longer lints on `From::from` for `Copy` types
+  [#8807](https://github.com/rust-lang/rust-clippy/pull/8807)
+* [`redundant_allocation`]: No longer lints on fat pointers that would become
+  thin pointers [#8813](https://github.com/rust-lang/rust-clippy/pull/8813)
+* [`derive_partial_eq_without_eq`]:
+    * Handle differing predicates applied by `#[derive(PartialEq)]` and
+      `#[derive(Eq)]`
+      [#8869](https://github.com/rust-lang/rust-clippy/pull/8869)
+    * No longer lints on non-public types and better handles generics
+      [#8950](https://github.com/rust-lang/rust-clippy/pull/8950)
+* [`empty_line_after_outer_attr`]: No longer lints empty lines in inner
+  string values [#8892](https://github.com/rust-lang/rust-clippy/pull/8892)
+* [`branches_sharing_code`]: No longer lints when using different binding names
+  [#8901](https://github.com/rust-lang/rust-clippy/pull/8901)
+* [`significant_drop_in_scrutinee`]: No longer lints on Try `?` and `await`
+  desugared expressions [#8902](https://github.com/rust-lang/rust-clippy/pull/8902)
+* [`checked_conversions`]: No longer lints in `const` contexts
+  [#8907](https://github.com/rust-lang/rust-clippy/pull/8907)
+* [`iter_overeager_cloned`]: No longer lints on `.cloned().flatten()` when
+  `T::Item` doesn't implement `IntoIterator`
+  [#8960](https://github.com/rust-lang/rust-clippy/pull/8960)
+
+### Suggestion Fixes/Improvements
+
+* [`vec_init_then_push`]: Suggest to remove `mut` binding when possible
+  [#8699](https://github.com/rust-lang/rust-clippy/pull/8699)
+* [`manual_range_contains`]: Fix suggestion for integers with different signs
+  [#8763](https://github.com/rust-lang/rust-clippy/pull/8763)
+* [`identity_op`]: Add parenthesis to suggestions where required
+  [#8786](https://github.com/rust-lang/rust-clippy/pull/8786)
+* [`cast_lossless`]: No longer gives wrong suggestion on `usize`/`isize`->`f64`
+  [#8778](https://github.com/rust-lang/rust-clippy/pull/8778)
+* [`rc_clone_in_vec_init`]: Add suggestion
+  [#8814](https://github.com/rust-lang/rust-clippy/pull/8814)
+* The "unknown field" error messages for config files now wraps the field names
+  [#8823](https://github.com/rust-lang/rust-clippy/pull/8823)
+* [`cast_abs_to_unsigned`]: Do not remove cast if it's required
+  [#8876](https://github.com/rust-lang/rust-clippy/pull/8876)
+* [`significant_drop_in_scrutinee`]: Improve lint message for types that are not
+  references and not trivially clone-able
+  [#8902](https://github.com/rust-lang/rust-clippy/pull/8902)
+* [`for_loops_over_fallibles`]: Now suggests the correct variant of `iter()`,
+  `iter_mut()` or `into_iter()`
+  [#8941](https://github.com/rust-lang/rust-clippy/pull/8941)
+
+### ICE Fixes
+
+* Fix ICE in [`let_unit_value`] when calling a `static`/`const` callable type
+  [#8835](https://github.com/rust-lang/rust-clippy/pull/8835)
+* Fix ICEs on callable `static`/`const`s
+  [#8896](https://github.com/rust-lang/rust-clippy/pull/8896)
+* [`needless_late_init`]
+  [#8912](https://github.com/rust-lang/rust-clippy/pull/8912)
+* Fix ICE in shadow lints
+  [#8913](https://github.com/rust-lang/rust-clippy/pull/8913)
+
+### Documentation Improvements
+
+* Clippy has a [Book](https://doc.rust-lang.org/nightly/clippy/) now!
+  [#7359](https://github.com/rust-lang/rust-clippy/pull/7359)
+* Add a *copy lint name*-button to Clippy's lint list
+  [#8839](https://github.com/rust-lang/rust-clippy/pull/8839)
+* Display past names of renamed lints on Clippy's lint list
+  [#8843](https://github.com/rust-lang/rust-clippy/pull/8843)
+* Add the ability to show the lint output in the lint list
+  [#8947](https://github.com/rust-lang/rust-clippy/pull/8947)
 
 ## Rust 1.62
 
-Current stable, released 2022-06-30
+Released 2022-06-30
 
 [d0cf3481...7c21f91b](https://github.com/rust-lang/rust-clippy/compare/d0cf3481...7c21f91b)
 
@@ -3437,7 +3583,7 @@ Released 2018-09-13
 [`almost_complete_letter_range`]: https://rust-lang.github.io/rust-clippy/master/index.html#almost_complete_letter_range
 [`almost_swapped`]: https://rust-lang.github.io/rust-clippy/master/index.html#almost_swapped
 [`approx_constant`]: https://rust-lang.github.io/rust-clippy/master/index.html#approx_constant
-[`arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#arithmetic
+[`arithmetic_side_effects`]: https://rust-lang.github.io/rust-clippy/master/index.html#arithmetic_side_effects
 [`as_conversions`]: https://rust-lang.github.io/rust-clippy/master/index.html#as_conversions
 [`as_underscore`]: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore
 [`assertions_on_constants`]: https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_constants
@@ -3457,6 +3603,7 @@ Released 2018-09-13
 [`blocks_in_if_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_if_conditions
 [`bool_assert_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_assert_comparison
 [`bool_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_comparison
+[`bool_to_int_with_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_to_int_with_if
 [`borrow_as_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_as_ptr
 [`borrow_deref_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_deref_ref
 [`borrow_interior_mutable_const`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_interior_mutable_const
@@ -3481,6 +3628,7 @@ Released 2018-09-13
 [`cast_ref_to_mut`]: https://rust-lang.github.io/rust-clippy/master/index.html#cast_ref_to_mut
 [`cast_sign_loss`]: https://rust-lang.github.io/rust-clippy/master/index.html#cast_sign_loss
 [`cast_slice_different_sizes`]: https://rust-lang.github.io/rust-clippy/master/index.html#cast_slice_different_sizes
+[`cast_slice_from_raw_parts`]: https://rust-lang.github.io/rust-clippy/master/index.html#cast_slice_from_raw_parts
 [`char_lit_as_u8`]: https://rust-lang.github.io/rust-clippy/master/index.html#char_lit_as_u8
 [`chars_last_cmp`]: https://rust-lang.github.io/rust-clippy/master/index.html#chars_last_cmp
 [`chars_next_cmp`]: https://rust-lang.github.io/rust-clippy/master/index.html#chars_next_cmp
@@ -3496,6 +3644,7 @@ Released 2018-09-13
 [`collapsible_else_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_else_if
 [`collapsible_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
 [`collapsible_match`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
+[`collapsible_str_replace`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_str_replace
 [`comparison_chain`]: https://rust-lang.github.io/rust-clippy/master/index.html#comparison_chain
 [`comparison_to_empty`]: https://rust-lang.github.io/rust-clippy/master/index.html#comparison_to_empty
 [`const_static_lifetime`]: https://rust-lang.github.io/rust-clippy/master/index.html#const_static_lifetime
@@ -3651,11 +3800,14 @@ Released 2018-09-13
 [`items_after_statements`]: https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements
 [`iter_cloned_collect`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_cloned_collect
 [`iter_count`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_count
+[`iter_kv_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_kv_map
 [`iter_next_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_next_loop
 [`iter_next_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_next_slice
 [`iter_not_returning_iterator`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_not_returning_iterator
 [`iter_nth`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_nth
 [`iter_nth_zero`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_nth_zero
+[`iter_on_empty_collections`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_on_empty_collections
+[`iter_on_single_items`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_on_single_items
 [`iter_overeager_cloned`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_overeager_cloned
 [`iter_skip_next`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_skip_next
 [`iter_with_drain`]: https://rust-lang.github.io/rust-clippy/master/index.html#iter_with_drain
@@ -3697,6 +3849,7 @@ Released 2018-09-13
 [`manual_saturating_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_saturating_arithmetic
 [`manual_split_once`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_split_once
 [`manual_str_repeat`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_str_repeat
+[`manual_string_new`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_string_new
 [`manual_strip`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_strip
 [`manual_swap`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_swap
 [`manual_unwrap_or`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_unwrap_or
@@ -3747,6 +3900,7 @@ Released 2018-09-13
 [`module_name_repetitions`]: https://rust-lang.github.io/rust-clippy/master/index.html#module_name_repetitions
 [`modulo_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#modulo_arithmetic
 [`modulo_one`]: https://rust-lang.github.io/rust-clippy/master/index.html#modulo_one
+[`multi_assignments`]: https://rust-lang.github.io/rust-clippy/master/index.html#multi_assignments
 [`multiple_crate_versions`]: https://rust-lang.github.io/rust-clippy/master/index.html#multiple_crate_versions
 [`multiple_inherent_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#multiple_inherent_impl
 [`must_use_candidate`]: https://rust-lang.github.io/rust-clippy/master/index.html#must_use_candidate
@@ -3827,6 +3981,7 @@ Released 2018-09-13
 [`partialeq_to_none`]: https://rust-lang.github.io/rust-clippy/master/index.html#partialeq_to_none
 [`path_buf_push_overwrite`]: https://rust-lang.github.io/rust-clippy/master/index.html#path_buf_push_overwrite
 [`pattern_type_mismatch`]: https://rust-lang.github.io/rust-clippy/master/index.html#pattern_type_mismatch
+[`positional_named_format_parameters`]: https://rust-lang.github.io/rust-clippy/master/index.html#positional_named_format_parameters
 [`possible_missing_comma`]: https://rust-lang.github.io/rust-clippy/master/index.html#possible_missing_comma
 [`precedence`]: https://rust-lang.github.io/rust-clippy/master/index.html#precedence
 [`print_in_format_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_in_format_impl
@@ -3872,6 +4027,7 @@ Released 2018-09-13
 [`replace_consts`]: https://rust-lang.github.io/rust-clippy/master/index.html#replace_consts
 [`rest_pat_in_fully_bound_structs`]: https://rust-lang.github.io/rust-clippy/master/index.html#rest_pat_in_fully_bound_structs
 [`result_expect_used`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_expect_used
+[`result_large_err`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_large_err
 [`result_map_or_into_option`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_map_or_into_option
 [`result_map_unit_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_map_unit_fn
 [`result_map_unwrap_or_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_map_unwrap_or_else
@@ -3930,6 +4086,7 @@ Released 2018-09-13
 [`suspicious_op_assign_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_op_assign_impl
 [`suspicious_operation_groupings`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_operation_groupings
 [`suspicious_splitn`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_splitn
+[`suspicious_to_owned`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_to_owned
 [`suspicious_unary_op_formatting`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_unary_op_formatting
 [`swap_ptr_to_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#swap_ptr_to_ref
 [`tabs_in_doc_comments`]: https://rust-lang.github.io/rust-clippy/master/index.html#tabs_in_doc_comments
@@ -4002,6 +4159,7 @@ Released 2018-09-13
 [`unused_collect`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_collect
 [`unused_io_amount`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_io_amount
 [`unused_label`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_label
+[`unused_peekable`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_peekable
 [`unused_rounding`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_rounding
 [`unused_self`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_self
 [`unused_unit`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_unit
diff --git a/src/tools/clippy/CONTRIBUTING.md b/src/tools/clippy/CONTRIBUTING.md
index 28b4cfd5f099..6c977b2cacab 100644
--- a/src/tools/clippy/CONTRIBUTING.md
+++ b/src/tools/clippy/CONTRIBUTING.md
@@ -110,23 +110,28 @@ Just make sure to remove the dependencies again before finally making a pull req
 [IntelliJ_rust_homepage]: https://intellij-rust.github.io/
 
 ### Rust Analyzer
-As of [#6869][6869], [`rust-analyzer`][ra_homepage] can understand that Clippy uses compiler-internals
-using `extern crate` when `package.metadata.rust-analyzer.rustc_private` is set to `true` in Clippy's `Cargo.toml.`
-You will require a `nightly` toolchain with the `rustc-dev` component installed.
-Make sure that in the `rust-analyzer` configuration, you set
+For [`rust-analyzer`][ra_homepage] to work correctly make sure that in the `rust-analyzer` configuration you set
+
 ```json
 { "rust-analyzer.rustc.source": "discover" }
 ```
-and
-```json
-{ "rust-analyzer.updates.channel": "nightly" }
-```
+
 You should be able to see information on things like `Expr` or `EarlyContext` now if you hover them, also
 a lot more type hints.
-This will work with `rust-analyzer 2021-03-15` shipped in nightly `1.52.0-nightly (107896c32 2021-03-15)` or later.
+
+To have `rust-analyzer` also work in the `clippy_dev` and `lintcheck` crates, add the following configuration
+
+```json
+{
+    "rust-analyzer.linkedProjects": [
+        "./Cargo.toml",
+        "clippy_dev/Cargo.toml",
+        "lintcheck/Cargo.toml",
+    ]
+}
+```
 
 [ra_homepage]: https://rust-analyzer.github.io/
-[6869]: https://github.com/rust-lang/rust-clippy/pull/6869
 
 ## How Clippy works
 
diff --git a/src/tools/clippy/book/src/development/adding_lints.md b/src/tools/clippy/book/src/development/adding_lints.md
index da781eb970df..b1e843bc7f4c 100644
--- a/src/tools/clippy/book/src/development/adding_lints.md
+++ b/src/tools/clippy/book/src/development/adding_lints.md
@@ -90,6 +90,7 @@ We start by opening the test file created at `tests/ui/foo_functions.rs`.
 Update the file with some examples to get started:
 
 ```rust
+#![allow(unused)]
 #![warn(clippy::foo_functions)]
 
 // Impl methods
diff --git a/src/tools/clippy/book/src/development/common_tools_writing_lints.md b/src/tools/clippy/book/src/development/common_tools_writing_lints.md
index 15e00c7d7ce4..f5aa06e4bf65 100644
--- a/src/tools/clippy/book/src/development/common_tools_writing_lints.md
+++ b/src/tools/clippy/book/src/development/common_tools_writing_lints.md
@@ -66,7 +66,7 @@ Starting with an `expr`, you can check whether it is calling a specific method
 impl<'tcx> LateLintPass<'tcx> for MyStructLint {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
         // Check our expr is calling a method
-        if let hir::ExprKind::MethodCall(path, _, [_self_arg, ..]) = &expr.kind
+        if let hir::ExprKind::MethodCall(path, _, _self_arg, ..) = &expr.kind
             // Check the name of this method is `some_method`
             && path.ident.name == sym!(some_method)
             // Optionally, check the type of the self argument.
@@ -123,7 +123,8 @@ There are three ways to do this, depending on if the target trait has a
 diagnostic item, lang item or neither.
 
 ```rust
-use clippy_utils::{implements_trait, is_trait_method, match_trait_method, paths};
+use clippy_utils::ty::implements_trait;
+use clippy_utils::is_trait_method;
 use rustc_span::symbol::sym;
 
 impl LateLintPass<'_> for MyStructLint {
@@ -143,13 +144,6 @@ impl LateLintPass<'_> for MyStructLint {
             .map_or(false, |id| implements_trait(cx, ty, id, &[])) {
                 // `expr` implements `Drop` trait
             }
-
-        // 3. Using the type path with the expression
-        // we use `match_trait_method` function from Clippy's utils
-        // (This method should be avoided if possible)
-        if match_trait_method(cx, expr, &paths::INTO) {
-            // `expr` implements `Into` trait
-        }
     }
 }
 ```
@@ -233,8 +227,9 @@ functions to deal with macros:
   crates
 
   ```rust
-  #[macro_use]
-  extern crate a_crate_with_macros;
+  use rustc_middle::lint::in_external_macro;
+
+  use a_crate_with_macros::foo;
 
   // `foo` is defined in `a_crate_with_macros`
   foo!("bar");
diff --git a/src/tools/clippy/clippy_dev/src/bless.rs b/src/tools/clippy/clippy_dev/src/bless.rs
index f5c51b9474fc..92b2771f3fe7 100644
--- a/src/tools/clippy/clippy_dev/src/bless.rs
+++ b/src/tools/clippy/clippy_dev/src/bless.rs
@@ -37,7 +37,7 @@ fn update_reference_file(test_output_entry: &DirEntry, ignore_timestamp: bool) {
         return;
     }
 
-    let test_output_file = fs::read(&test_output_path).expect("Unable to read test output file");
+    let test_output_file = fs::read(test_output_path).expect("Unable to read test output file");
     let reference_file = fs::read(&reference_file_path).unwrap_or_default();
 
     if test_output_file != reference_file {
diff --git a/src/tools/clippy/clippy_dev/src/fmt.rs b/src/tools/clippy/clippy_dev/src/fmt.rs
index 3b27f061eb0b..357cf6fc43aa 100644
--- a/src/tools/clippy/clippy_dev/src/fmt.rs
+++ b/src/tools/clippy/clippy_dev/src/fmt.rs
@@ -46,7 +46,7 @@ pub fn run(check: bool, verbose: bool) {
         // dependency
         if fs::read_to_string(project_root.join("Cargo.toml"))
             .expect("Failed to read clippy Cargo.toml")
-            .contains(&"[target.'cfg(NOT_A_PLATFORM)'.dependencies]")
+            .contains("[target.'cfg(NOT_A_PLATFORM)'.dependencies]")
         {
             return Err(CliError::IntellijSetupActive);
         }
@@ -193,10 +193,10 @@ fn rustfmt_test(context: &FmtContext) -> Result<(), CliError> {
     let args = &["--version"];
 
     if context.verbose {
-        println!("{}", format_command(&program, &dir, args));
+        println!("{}", format_command(program, &dir, args));
     }
 
-    let output = Command::new(&program).current_dir(&dir).args(args.iter()).output()?;
+    let output = Command::new(program).current_dir(&dir).args(args.iter()).output()?;
 
     if output.status.success() {
         Ok(())
@@ -207,7 +207,7 @@ fn rustfmt_test(context: &FmtContext) -> Result<(), CliError> {
         Err(CliError::RustfmtNotInstalled)
     } else {
         Err(CliError::CommandFailed(
-            format_command(&program, &dir, args),
+            format_command(program, &dir, args),
             std::str::from_utf8(&output.stderr).unwrap_or("").to_string(),
         ))
     }
diff --git a/src/tools/clippy/clippy_dev/src/lib.rs b/src/tools/clippy/clippy_dev/src/lib.rs
index 82574a8e64b0..80bb83af43b1 100644
--- a/src/tools/clippy/clippy_dev/src/lib.rs
+++ b/src/tools/clippy/clippy_dev/src/lib.rs
@@ -1,5 +1,4 @@
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(once_cell)]
 #![feature(rustc_private)]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
diff --git a/src/tools/clippy/clippy_dev/src/new_lint.rs b/src/tools/clippy/clippy_dev/src/new_lint.rs
index 10a8f31f4573..02cb13a1d8af 100644
--- a/src/tools/clippy/clippy_dev/src/new_lint.rs
+++ b/src/tools/clippy/clippy_dev/src/new_lint.rs
@@ -120,15 +120,17 @@ fn add_lint(lint: &LintData<'_>, enable_msrv: bool) -> io::Result<()> {
 
     let new_lint = if enable_msrv {
         format!(
-            "store.register_{lint_pass}_pass(move || Box::new({module_name}::{camel_name}::new(msrv)));\n    ",
+            "store.register_{lint_pass}_pass(move |{ctor_arg}| Box::new({module_name}::{camel_name}::new(msrv)));\n    ",
             lint_pass = lint.pass,
+            ctor_arg = if lint.pass == "late" { "_" } else { "" },
             module_name = lint.name,
             camel_name = to_camel_case(lint.name),
         )
     } else {
         format!(
-            "store.register_{lint_pass}_pass(|| Box::new({module_name}::{camel_name}));\n    ",
+            "store.register_{lint_pass}_pass(|{ctor_arg}| Box::new({module_name}::{camel_name}));\n    ",
             lint_pass = lint.pass,
+            ctor_arg = if lint.pass == "late" { "_" } else { "" },
             module_name = lint.name,
             camel_name = to_camel_case(lint.name),
         )
@@ -155,7 +157,7 @@ fn to_camel_case(name: &str) -> String {
     name.split('_')
         .map(|s| {
             if s.is_empty() {
-                String::from("")
+                String::new()
             } else {
                 [&s[0..1].to_uppercase(), &s[1..]].concat()
             }
@@ -186,6 +188,7 @@ pub(crate) fn get_stabilization_version() -> String {
 fn get_test_file_contents(lint_name: &str, header_commands: Option<&str>) -> String {
     let mut contents = format!(
         indoc! {"
+            #![allow(unused)]
             #![warn(clippy::{})]
 
             fn main() {{
diff --git a/src/tools/clippy/clippy_dev/src/update_lints.rs b/src/tools/clippy/clippy_dev/src/update_lints.rs
index 05e79a241884..b95061bf81a2 100644
--- a/src/tools/clippy/clippy_dev/src/update_lints.rs
+++ b/src/tools/clippy/clippy_dev/src/update_lints.rs
@@ -3,7 +3,7 @@ use aho_corasick::AhoCorasickBuilder;
 use indoc::writedoc;
 use itertools::Itertools;
 use rustc_lexer::{tokenize, unescape, LiteralKind, TokenKind};
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeSet, HashMap, HashSet};
 use std::ffi::OsStr;
 use std::fmt::Write;
 use std::fs::{self, OpenOptions};
@@ -124,6 +124,8 @@ fn generate_lint_files(
     let content = gen_lint_group_list("all", all_group_lints);
     process_file("clippy_lints/src/lib.register_all.rs", update_mode, &content);
 
+    update_docs(update_mode, &usable_lints);
+
     for (lint_group, lints) in Lint::by_lint_group(usable_lints.into_iter().chain(internal_lints)) {
         let content = gen_lint_group_list(&lint_group, lints.iter());
         process_file(
@@ -140,6 +142,62 @@ fn generate_lint_files(
     process_file("tests/ui/rename.rs", update_mode, &content);
 }
 
+fn update_docs(update_mode: UpdateMode, usable_lints: &[Lint]) {
+    replace_region_in_file(update_mode, Path::new("src/docs.rs"), "docs! {\n", "\n}\n", |res| {
+        for name in usable_lints.iter().map(|lint| lint.name.clone()).sorted() {
+            writeln!(res, r#"    "{name}","#).unwrap();
+        }
+    });
+
+    if update_mode == UpdateMode::Check {
+        let mut extra = BTreeSet::new();
+        let mut lint_names = usable_lints
+            .iter()
+            .map(|lint| lint.name.clone())
+            .collect::<BTreeSet<_>>();
+        for file in std::fs::read_dir("src/docs").unwrap() {
+            let filename = file.unwrap().file_name().into_string().unwrap();
+            if let Some(name) = filename.strip_suffix(".txt") {
+                if !lint_names.remove(name) {
+                    extra.insert(name.to_string());
+                }
+            }
+        }
+
+        let failed = print_lint_names("extra lint docs:", &extra) | print_lint_names("missing lint docs:", &lint_names);
+
+        if failed {
+            exit_with_failure();
+        }
+    } else {
+        if std::fs::remove_dir_all("src/docs").is_err() {
+            eprintln!("could not remove src/docs directory");
+        }
+        if std::fs::create_dir("src/docs").is_err() {
+            eprintln!("could not recreate src/docs directory");
+        }
+    }
+    for lint in usable_lints {
+        process_file(
+            Path::new("src/docs").join(lint.name.clone() + ".txt"),
+            update_mode,
+            &lint.documentation,
+        );
+    }
+}
+
+fn print_lint_names(header: &str, lints: &BTreeSet<String>) -> bool {
+    if lints.is_empty() {
+        return false;
+    }
+    println!("{}", header);
+    for lint in lints.iter().sorted() {
+        println!("    {}", lint);
+    }
+    println!();
+    true
+}
+
 pub fn print_lints() {
     let (lint_list, _, _) = gather_all();
     let usable_lints = Lint::usable_lints(&lint_list);
@@ -418,7 +476,7 @@ fn remove_lint_declaration(name: &str, path: &Path, lints: &mut Vec<Lint>) -> io
             .expect("failed to find `impl_lint_pass` terminator");
 
         impl_lint_pass_end += impl_lint_pass_start;
-        if let Some(lint_name_pos) = content[impl_lint_pass_start..impl_lint_pass_end].find(&lint_name_upper) {
+        if let Some(lint_name_pos) = content[impl_lint_pass_start..impl_lint_pass_end].find(lint_name_upper) {
             let mut lint_name_end = impl_lint_pass_start + (lint_name_pos + lint_name_upper.len());
             for c in content[lint_name_end..impl_lint_pass_end].chars() {
                 // Remove trailing whitespace
@@ -451,7 +509,7 @@ fn remove_lint_declaration(name: &str, path: &Path, lints: &mut Vec<Lint>) -> io
                 }
 
                 let mut content =
-                    fs::read_to_string(&path).unwrap_or_else(|_| panic!("failed to read `{}`", path.to_string_lossy()));
+                    fs::read_to_string(path).unwrap_or_else(|_| panic!("failed to read `{}`", path.to_string_lossy()));
 
                 eprintln!(
                     "warn: you will have to manually remove any code related to `{}` from `{}`",
@@ -589,17 +647,26 @@ struct Lint {
     desc: String,
     module: String,
     declaration_range: Range<usize>,
+    documentation: String,
 }
 
 impl Lint {
     #[must_use]
-    fn new(name: &str, group: &str, desc: &str, module: &str, declaration_range: Range<usize>) -> Self {
+    fn new(
+        name: &str,
+        group: &str,
+        desc: &str,
+        module: &str,
+        declaration_range: Range<usize>,
+        documentation: String,
+    ) -> Self {
         Self {
             name: name.to_lowercase(),
             group: group.into(),
             desc: remove_line_splices(desc),
             module: module.into(),
             declaration_range,
+            documentation,
         }
     }
 
@@ -852,27 +919,35 @@ fn parse_contents(contents: &str, module: &str, lints: &mut Vec<Lint>) {
          }| token_kind == &TokenKind::Ident && *content == "declare_clippy_lint",
     ) {
         let start = range.start;
-
-        let mut iter = iter
-            .by_ref()
-            .filter(|t| !matches!(t.token_kind, TokenKind::Whitespace | TokenKind::LineComment { .. }));
+        let mut docs = String::with_capacity(128);
+        let mut iter = iter.by_ref().filter(|t| !matches!(t.token_kind, TokenKind::Whitespace));
         // matches `!{`
         match_tokens!(iter, Bang OpenBrace);
-        match iter.next() {
-            // #[clippy::version = "version"] pub
-            Some(LintDeclSearchResult {
-                token_kind: TokenKind::Pound,
-                ..
-            }) => {
-                match_tokens!(iter, OpenBracket Ident Colon Colon Ident Eq Literal{..} CloseBracket Ident);
-            },
-            // pub
-            Some(LintDeclSearchResult {
-                token_kind: TokenKind::Ident,
-                ..
-            }) => (),
-            _ => continue,
+        let mut in_code = false;
+        while let Some(t) = iter.next() {
+            match t.token_kind {
+                TokenKind::LineComment { .. } => {
+                    if let Some(line) = t.content.strip_prefix("/// ").or_else(|| t.content.strip_prefix("///")) {
+                        if line.starts_with("```") {
+                            docs += "```\n";
+                            in_code = !in_code;
+                        } else if !(in_code && line.starts_with("# ")) {
+                            docs += line;
+                            docs.push('\n');
+                        }
+                    }
+                },
+                TokenKind::Pound => {
+                    match_tokens!(iter, OpenBracket Ident Colon Colon Ident Eq Literal{..} CloseBracket Ident);
+                    break;
+                },
+                TokenKind::Ident => {
+                    break;
+                },
+                _ => {},
+            }
         }
+        docs.pop(); // remove final newline
 
         let (name, group, desc) = match_tokens!(
             iter,
@@ -890,7 +965,7 @@ fn parse_contents(contents: &str, module: &str, lints: &mut Vec<Lint>) {
             ..
         }) = iter.next()
         {
-            lints.push(Lint::new(name, group, desc, module, start..range.end));
+            lints.push(Lint::new(name, group, desc, module, start..range.end, docs));
         }
     }
 }
@@ -977,7 +1052,11 @@ fn remove_line_splices(s: &str) -> String {
         .and_then(|s| s.strip_suffix('"'))
         .unwrap_or_else(|| panic!("expected quoted string, found `{}`", s));
     let mut res = String::with_capacity(s.len());
-    unescape::unescape_literal(s, unescape::Mode::Str, &mut |range, _| res.push_str(&s[range]));
+    unescape::unescape_literal(s, unescape::Mode::Str, &mut |range, ch| {
+        if ch.is_ok() {
+            res.push_str(&s[range]);
+        }
+    });
     res
 }
 
@@ -1116,6 +1195,7 @@ mod tests {
                 "\"really long text\"",
                 "module_name",
                 Range::default(),
+                String::new(),
             ),
             Lint::new(
                 "doc_markdown",
@@ -1123,6 +1203,7 @@ mod tests {
                 "\"single line\"",
                 "module_name",
                 Range::default(),
+                String::new(),
             ),
         ];
         assert_eq!(expected, result);
@@ -1162,6 +1243,7 @@ mod tests {
                 "\"abc\"",
                 "module_name",
                 Range::default(),
+                String::new(),
             ),
             Lint::new(
                 "should_assert_eq2",
@@ -1169,6 +1251,7 @@ mod tests {
                 "\"abc\"",
                 "module_name",
                 Range::default(),
+                String::new(),
             ),
             Lint::new(
                 "should_assert_eq2",
@@ -1176,6 +1259,7 @@ mod tests {
                 "\"abc\"",
                 "module_name",
                 Range::default(),
+                String::new(),
             ),
         ];
         let expected = vec![Lint::new(
@@ -1184,6 +1268,7 @@ mod tests {
             "\"abc\"",
             "module_name",
             Range::default(),
+            String::new(),
         )];
         assert_eq!(expected, Lint::usable_lints(&lints));
     }
@@ -1191,22 +1276,51 @@ mod tests {
     #[test]
     fn test_by_lint_group() {
         let lints = vec![
-            Lint::new("should_assert_eq", "group1", "\"abc\"", "module_name", Range::default()),
+            Lint::new(
+                "should_assert_eq",
+                "group1",
+                "\"abc\"",
+                "module_name",
+                Range::default(),
+                String::new(),
+            ),
             Lint::new(
                 "should_assert_eq2",
                 "group2",
                 "\"abc\"",
                 "module_name",
                 Range::default(),
+                String::new(),
+            ),
+            Lint::new(
+                "incorrect_match",
+                "group1",
+                "\"abc\"",
+                "module_name",
+                Range::default(),
+                String::new(),
             ),
-            Lint::new("incorrect_match", "group1", "\"abc\"", "module_name", Range::default()),
         ];
         let mut expected: HashMap<String, Vec<Lint>> = HashMap::new();
         expected.insert(
             "group1".to_string(),
             vec![
-                Lint::new("should_assert_eq", "group1", "\"abc\"", "module_name", Range::default()),
-                Lint::new("incorrect_match", "group1", "\"abc\"", "module_name", Range::default()),
+                Lint::new(
+                    "should_assert_eq",
+                    "group1",
+                    "\"abc\"",
+                    "module_name",
+                    Range::default(),
+                    String::new(),
+                ),
+                Lint::new(
+                    "incorrect_match",
+                    "group1",
+                    "\"abc\"",
+                    "module_name",
+                    Range::default(),
+                    String::new(),
+                ),
             ],
         );
         expected.insert(
@@ -1217,6 +1331,7 @@ mod tests {
                 "\"abc\"",
                 "module_name",
                 Range::default(),
+                String::new(),
             )],
         );
         assert_eq!(expected, Lint::by_lint_group(lints.into_iter()));
@@ -1255,9 +1370,30 @@ mod tests {
     #[test]
     fn test_gen_lint_group_list() {
         let lints = vec![
-            Lint::new("abc", "group1", "\"abc\"", "module_name", Range::default()),
-            Lint::new("should_assert_eq", "group1", "\"abc\"", "module_name", Range::default()),
-            Lint::new("internal", "internal_style", "\"abc\"", "module_name", Range::default()),
+            Lint::new(
+                "abc",
+                "group1",
+                "\"abc\"",
+                "module_name",
+                Range::default(),
+                String::new(),
+            ),
+            Lint::new(
+                "should_assert_eq",
+                "group1",
+                "\"abc\"",
+                "module_name",
+                Range::default(),
+                String::new(),
+            ),
+            Lint::new(
+                "internal",
+                "internal_style",
+                "\"abc\"",
+                "module_name",
+                Range::default(),
+                String::new(),
+            ),
         ];
         let expected = GENERATED_FILE_COMMENT.to_string()
             + &[
diff --git a/src/tools/clippy/clippy_lints/src/almost_complete_letter_range.rs b/src/tools/clippy/clippy_lints/src/almost_complete_letter_range.rs
index 59a7c5354006..073e4af1318e 100644
--- a/src/tools/clippy/clippy_lints/src/almost_complete_letter_range.rs
+++ b/src/tools/clippy/clippy_lints/src/almost_complete_letter_range.rs
@@ -4,6 +4,7 @@ use clippy_utils::{meets_msrv, msrvs};
 use rustc_ast::ast::{Expr, ExprKind, LitKind, Pat, PatKind, RangeEnd, RangeLimits};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::Span;
@@ -79,6 +80,7 @@ fn check_range(cx: &EarlyContext<'_>, span: Span, start: &Expr, end: &Expr, sugg
             (LitKind::Byte(b'a') | LitKind::Char('a'), LitKind::Byte(b'z') | LitKind::Char('z'))
             | (LitKind::Byte(b'A') | LitKind::Char('A'), LitKind::Byte(b'Z') | LitKind::Char('Z'))
         )
+        && !in_external_macro(cx.sess(), span)
     {
         span_lint_and_then(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/as_underscore.rs b/src/tools/clippy/clippy_lints/src/as_underscore.rs
deleted file mode 100644
index 0bdef9d0a7e8..000000000000
--- a/src/tools/clippy/clippy_lints/src/as_underscore.rs
+++ /dev/null
@@ -1,74 +0,0 @@
-use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_then};
-use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, TyKind};
-use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Check for the usage of `as _` conversion using inferred type.
-    ///
-    /// ### Why is this bad?
-    /// The conversion might include lossy conversion and dangerous cast that might go
-    /// undetected du to the type being inferred.
-    ///
-    /// The lint is allowed by default as using `_` is less wordy than always specifying the type.
-    ///
-    /// ### Example
-    /// ```rust
-    /// fn foo(n: usize) {}
-    /// let n: u16 = 256;
-    /// foo(n as _);
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// fn foo(n: usize) {}
-    /// let n: u16 = 256;
-    /// foo(n as usize);
-    /// ```
-    #[clippy::version = "1.63.0"]
-    pub AS_UNDERSCORE,
-    restriction,
-    "detects `as _` conversion"
-}
-declare_lint_pass!(AsUnderscore => [AS_UNDERSCORE]);
-
-impl<'tcx> LateLintPass<'tcx> for AsUnderscore {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) {
-        if in_external_macro(cx.sess(), expr.span) {
-            return;
-        }
-
-        if let ExprKind::Cast(_, ty) = expr.kind && let TyKind::Infer = ty.kind {
-
-            let ty_resolved = cx.typeck_results().expr_ty(expr);
-            if let ty::Error(_) = ty_resolved.kind() {
-                span_lint_and_help(
-                    cx,
-                AS_UNDERSCORE,
-                expr.span,
-                "using `as _` conversion",
-                None,
-                "consider giving the type explicitly",
-                );
-            } else {
-            span_lint_and_then(
-                cx,
-                AS_UNDERSCORE,
-                expr.span,
-                "using `as _` conversion",
-                |diag| {
-                    diag.span_suggestion(
-                        ty.span,
-                        "consider giving the type explicitly",
-                        ty_resolved,
-                        Applicability::MachineApplicable,
-                    );
-            }
-            );
-        }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/assertions_on_result_states.rs b/src/tools/clippy/clippy_lints/src/assertions_on_result_states.rs
index 6a6554f968b3..656dc5feeb57 100644
--- a/src/tools/clippy/clippy_lints/src/assertions_on_result_states.rs
+++ b/src/tools/clippy/clippy_lints/src/assertions_on_result_states.rs
@@ -1,9 +1,9 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::macros::{find_assert_args, root_macro_call_first_node, PanicExpn};
-use clippy_utils::path_res;
 use clippy_utils::source::snippet_with_context;
-use clippy_utils::ty::{implements_trait, is_copy, is_type_diagnostic_item};
+use clippy_utils::ty::{has_debug_impl, is_copy, is_type_diagnostic_item};
 use clippy_utils::usage::local_used_after_expr;
+use clippy_utils::{is_expr_final_block_expr, path_res};
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{Expr, ExprKind};
@@ -43,7 +43,7 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
             && matches!(cx.tcx.get_diagnostic_name(macro_call.def_id), Some(sym::assert_macro))
             && let Some((condition, panic_expn)) = find_assert_args(cx, e, macro_call.expn)
             && matches!(panic_expn, PanicExpn::Empty)
-            && let ExprKind::MethodCall(method_segment, [recv], _) = condition.kind
+            && let ExprKind::MethodCall(method_segment, recv, [], _) = condition.kind
             && let result_type_with_refs = cx.typeck_results().expr_ty(recv)
             && let result_type = result_type_with_refs.peel_refs()
             && is_type_diagnostic_item(cx, result_type, sym::Result)
@@ -58,6 +58,7 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
                     return;
                 }
             }
+            let semicolon = if is_expr_final_block_expr(cx.tcx, e) {";"} else {""};
             let mut app = Applicability::MachineApplicable;
             match method_segment.ident.as_str() {
                 "is_ok" if type_suitable_to_unwrap(cx, substs.type_at(1)) => {
@@ -68,8 +69,9 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
                         "called `assert!` with `Result::is_ok`",
                         "replace with",
                         format!(
-                            "{}.unwrap()",
-                            snippet_with_context(cx, recv.span, condition.span.ctxt(), "..", &mut app).0
+                            "{}.unwrap(){}",
+                            snippet_with_context(cx, recv.span, condition.span.ctxt(), "..", &mut app).0,
+                            semicolon
                         ),
                         app,
                     );
@@ -82,8 +84,9 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
                         "called `assert!` with `Result::is_err`",
                         "replace with",
                         format!(
-                            "{}.unwrap_err()",
-                            snippet_with_context(cx, recv.span, condition.span.ctxt(), "..", &mut app).0
+                            "{}.unwrap_err(){}",
+                            snippet_with_context(cx, recv.span, condition.span.ctxt(), "..", &mut app).0,
+                            semicolon
                         ),
                         app,
                     );
@@ -94,13 +97,6 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
     }
 }
 
-/// This checks whether a given type is known to implement Debug.
-fn has_debug_impl<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
-    cx.tcx
-        .get_diagnostic_item(sym::Debug)
-        .map_or(false, |debug| implements_trait(cx, ty, debug, &[]))
-}
-
 fn type_suitable_to_unwrap<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
     has_debug_impl(cx, ty) && !ty.is_unit() && !ty.is_never()
 }
diff --git a/src/tools/clippy/clippy_lints/src/async_yields_async.rs b/src/tools/clippy/clippy_lints/src/async_yields_async.rs
index 27c2896e1e5c..9464694a3b55 100644
--- a/src/tools/clippy/clippy_lints/src/async_yields_async.rs
+++ b/src/tools/clippy/clippy_lints/src/async_yields_async.rs
@@ -54,7 +54,7 @@ impl<'tcx> LateLintPass<'tcx> for AsyncYieldsAsync {
                     hir_id: body.value.hir_id,
                 };
                 let typeck_results = cx.tcx.typeck_body(body_id);
-                let expr_ty = typeck_results.expr_ty(&body.value);
+                let expr_ty = typeck_results.expr_ty(body.value);
 
                 if implements_trait(cx, expr_ty, future_trait_def_id, &[]) {
                     let return_expr_span = match &body.value.kind {
diff --git a/src/tools/clippy/clippy_lints/src/attrs.rs b/src/tools/clippy/clippy_lints/src/attrs.rs
index 4bcbeacf9feb..732dc2b43309 100644
--- a/src/tools/clippy/clippy_lints/src/attrs.rs
+++ b/src/tools/clippy/clippy_lints/src/attrs.rs
@@ -475,7 +475,7 @@ fn check_lint_reason(cx: &LateContext<'_>, name: Symbol, items: &[NestedMetaItem
 
 fn is_relevant_item(cx: &LateContext<'_>, item: &Item<'_>) -> bool {
     if let ItemKind::Fn(_, _, eid) = item.kind {
-        is_relevant_expr(cx, cx.tcx.typeck_body(eid), &cx.tcx.hir().body(eid).value)
+        is_relevant_expr(cx, cx.tcx.typeck_body(eid), cx.tcx.hir().body(eid).value)
     } else {
         true
     }
@@ -483,7 +483,7 @@ fn is_relevant_item(cx: &LateContext<'_>, item: &Item<'_>) -> bool {
 
 fn is_relevant_impl(cx: &LateContext<'_>, item: &ImplItem<'_>) -> bool {
     match item.kind {
-        ImplItemKind::Fn(_, eid) => is_relevant_expr(cx, cx.tcx.typeck_body(eid), &cx.tcx.hir().body(eid).value),
+        ImplItemKind::Fn(_, eid) => is_relevant_expr(cx, cx.tcx.typeck_body(eid), cx.tcx.hir().body(eid).value),
         _ => false,
     }
 }
@@ -492,7 +492,7 @@ fn is_relevant_trait(cx: &LateContext<'_>, item: &TraitItem<'_>) -> bool {
     match item.kind {
         TraitItemKind::Fn(_, TraitFn::Required(_)) => true,
         TraitItemKind::Fn(_, TraitFn::Provided(eid)) => {
-            is_relevant_expr(cx, cx.tcx.typeck_body(eid), &cx.tcx.hir().body(eid).value)
+            is_relevant_expr(cx, cx.tcx.typeck_body(eid), cx.tcx.hir().body(eid).value)
         },
         _ => false,
     }
diff --git a/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs b/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs
index ad206b5fb304..d9e2c9c8578f 100644
--- a/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs
+++ b/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs
@@ -55,7 +55,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ExVisitor<'a, 'tcx> {
             // do not lint if the closure is called using an iterator (see #1141)
             if_chain! {
                 if let Some(parent) = get_parent_expr(self.cx, expr);
-                if let ExprKind::MethodCall(_, [self_arg, ..], _) = &parent.kind;
+                if let ExprKind::MethodCall(_, self_arg, ..) = &parent.kind;
                 let caller = self.cx.typeck_results().expr_ty(self_arg);
                 if let Some(iter_id) = self.cx.tcx.get_diagnostic_item(sym::Iterator);
                 if implements_trait(self.cx, caller, iter_id, &[]);
@@ -117,7 +117,8 @@ impl<'tcx> LateLintPass<'tcx> for BlocksInIfConditions {
                             );
                         }
                     } else {
-                        let span = block.expr.as_ref().map_or_else(|| block.stmts[0].span, |e| e.span);
+                        let span =
+                            block.expr.as_ref().map_or_else(|| block.stmts[0].span, |e| e.span);
                         if span.from_expansion() || expr.span.from_expansion() {
                             return;
                         }
diff --git a/src/tools/clippy/clippy_lints/src/bool_to_int_with_if.rs b/src/tools/clippy/clippy_lints/src/bool_to_int_with_if.rs
new file mode 100644
index 000000000000..51e98cda8451
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/bool_to_int_with_if.rs
@@ -0,0 +1,136 @@
+use rustc_ast::LitKind;
+use rustc_hir::{Block, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+use clippy_utils::{diagnostics::span_lint_and_then, is_else_clause, sugg::Sugg};
+use rustc_errors::Applicability;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Instead of using an if statement to convert a bool to an int,
+    /// this lint suggests using a `from()` function or an `as` coercion.
+    ///
+    /// ### Why is this bad?
+    /// Coercion or `from()` is idiomatic way to convert bool to a number.
+    /// Both methods are guaranteed to return 1 for true, and 0 for false.
+    ///
+    /// See https://doc.rust-lang.org/std/primitive.bool.html#impl-From%3Cbool%3E
+    ///
+    /// ### Example
+    /// ```rust
+    /// # let condition = false;
+    /// if condition {
+    ///     1_i64
+    /// } else {
+    ///     0
+    /// };
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// # let condition = false;
+    /// i64::from(condition);
+    /// ```
+    /// or
+    /// ```rust
+    /// # let condition = false;
+    /// condition as i64;
+    /// ```
+    #[clippy::version = "1.65.0"]
+    pub BOOL_TO_INT_WITH_IF,
+    style,
+    "using if to convert bool to int"
+}
+declare_lint_pass!(BoolToIntWithIf => [BOOL_TO_INT_WITH_IF]);
+
+impl<'tcx> LateLintPass<'tcx> for BoolToIntWithIf {
+    fn check_expr(&mut self, ctx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) {
+        if !expr.span.from_expansion() {
+            check_if_else(ctx, expr);
+        }
+    }
+}
+
+fn check_if_else<'tcx>(ctx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) {
+    if let ExprKind::If(check, then, Some(else_)) = expr.kind
+        && let Some(then_lit) = int_literal(then)
+        && let Some(else_lit) = int_literal(else_)
+    {
+        let inverted = if
+            check_int_literal_equals_val(then_lit, 1)
+            && check_int_literal_equals_val(else_lit, 0) {
+            false
+        } else if
+            check_int_literal_equals_val(then_lit, 0)
+            && check_int_literal_equals_val(else_lit, 1) {
+            true
+        } else {
+            // Expression isn't boolean, exit
+            return;
+        };
+        let mut applicability = Applicability::MachineApplicable;
+        let snippet = {
+            let mut sugg = Sugg::hir_with_applicability(ctx, check, "..", &mut applicability);
+            if inverted {
+                sugg = !sugg;
+            }
+            sugg
+        };
+
+        let ty = ctx.typeck_results().expr_ty(then_lit); // then and else must be of same type
+
+        let suggestion = {
+            let wrap_in_curly = is_else_clause(ctx.tcx, expr);
+            let mut s = Sugg::NonParen(format!("{ty}::from({snippet})").into());
+            if wrap_in_curly {
+                s = s.blockify();
+            }
+            s
+        }; // when used in else clause if statement should be wrapped in curly braces
+
+        let into_snippet = snippet.clone().maybe_par();
+        let as_snippet = snippet.as_ty(ty);
+
+        span_lint_and_then(ctx,
+            BOOL_TO_INT_WITH_IF,
+            expr.span,
+            "boolean to int conversion using if",
+            |diag| {
+            diag.span_suggestion(
+                expr.span,
+                "replace with from",
+                suggestion,
+                applicability,
+            );
+            diag.note(format!("`{as_snippet}` or `{into_snippet}.into()` can also be valid options"));
+        });
+    };
+}
+
+// If block contains only a int literal expression, return literal expression
+fn int_literal<'tcx>(expr: &'tcx rustc_hir::Expr<'tcx>) -> Option<&'tcx rustc_hir::Expr<'tcx>> {
+    if let ExprKind::Block(block, _) = expr.kind
+        && let Block {
+            stmts: [],       // Shouldn't lint if statements with side effects
+            expr: Some(expr),
+            ..
+        } = block
+        && let ExprKind::Lit(lit) = &expr.kind
+        && let LitKind::Int(_, _) = lit.node
+    {
+        Some(expr)
+    } else {
+        None
+    }
+}
+
+fn check_int_literal_equals_val<'tcx>(expr: &'tcx rustc_hir::Expr<'tcx>, expected_value: u128) -> bool {
+    if let ExprKind::Lit(lit) = &expr.kind
+        && let LitKind::Int(val, _) = lit.node
+        && val == expected_value
+    {
+        true
+    } else {
+        false
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/booleans.rs b/src/tools/clippy/clippy_lints/src/booleans.rs
index 6eb78d21e826..03d262d5a59c 100644
--- a/src/tools/clippy/clippy_lints/src/booleans.rs
+++ b/src/tools/clippy/clippy_lints/src/booleans.rs
@@ -237,7 +237,7 @@ impl<'a, 'tcx, 'v> SuggestContext<'a, 'tcx, 'v> {
                 }
             },
             &Term(n) => {
-                let snip = snippet_opt(self.cx, self.terminals[n as usize].span)?;
+                let snip = snippet_opt(self.cx, self.terminals[n as usize].span.source_callsite())?;
                 self.output.push_str(&snip);
             },
         }
@@ -270,8 +270,8 @@ fn simplify_not(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
                 ))
             })
         },
-        ExprKind::MethodCall(path, args, _) if args.len() == 1 => {
-            let type_of_receiver = cx.typeck_results().expr_ty(&args[0]);
+        ExprKind::MethodCall(path, receiver, [], _) => {
+            let type_of_receiver = cx.typeck_results().expr_ty(receiver);
             if !is_type_diagnostic_item(cx, type_of_receiver, sym::Option)
                 && !is_type_diagnostic_item(cx, type_of_receiver, sym::Result)
             {
@@ -285,7 +285,7 @@ fn simplify_not(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
                     let path: &str = path.ident.name.as_str();
                     a == path
                 })
-                .and_then(|(_, neg_method)| Some(format!("{}.{}()", snippet_opt(cx, args[0].span)?, neg_method)))
+                .and_then(|(_, neg_method)| Some(format!("{}.{}()", snippet_opt(cx, receiver.span)?, neg_method)))
         },
         _ => None,
     }
diff --git a/src/tools/clippy/clippy_lints/src/borrow_as_ptr.rs b/src/tools/clippy/clippy_lints/src/borrow_as_ptr.rs
deleted file mode 100644
index 0993adbae2e6..000000000000
--- a/src/tools/clippy/clippy_lints/src/borrow_as_ptr.rs
+++ /dev/null
@@ -1,99 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::is_no_std_crate;
-use clippy_utils::source::snippet_opt;
-use clippy_utils::{meets_msrv, msrvs};
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, TyKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_semver::RustcVersion;
-use rustc_session::{declare_tool_lint, impl_lint_pass};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for the usage of `&expr as *const T` or
-    /// `&mut expr as *mut T`, and suggest using `ptr::addr_of` or
-    /// `ptr::addr_of_mut` instead.
-    ///
-    /// ### Why is this bad?
-    /// This would improve readability and avoid creating a reference
-    /// that points to an uninitialized value or unaligned place.
-    /// Read the `ptr::addr_of` docs for more information.
-    ///
-    /// ### Example
-    /// ```rust
-    /// let val = 1;
-    /// let p = &val as *const i32;
-    ///
-    /// let mut val_mut = 1;
-    /// let p_mut = &mut val_mut as *mut i32;
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// let val = 1;
-    /// let p = std::ptr::addr_of!(val);
-    ///
-    /// let mut val_mut = 1;
-    /// let p_mut = std::ptr::addr_of_mut!(val_mut);
-    /// ```
-    #[clippy::version = "1.60.0"]
-    pub BORROW_AS_PTR,
-    pedantic,
-    "borrowing just to cast to a raw pointer"
-}
-
-impl_lint_pass!(BorrowAsPtr => [BORROW_AS_PTR]);
-
-pub struct BorrowAsPtr {
-    msrv: Option<RustcVersion>,
-}
-
-impl BorrowAsPtr {
-    #[must_use]
-    pub fn new(msrv: Option<RustcVersion>) -> Self {
-        Self { msrv }
-    }
-}
-
-impl<'tcx> LateLintPass<'tcx> for BorrowAsPtr {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if !meets_msrv(self.msrv, msrvs::BORROW_AS_PTR) {
-            return;
-        }
-
-        if expr.span.from_expansion() {
-            return;
-        }
-
-        if_chain! {
-            if let ExprKind::Cast(left_expr, ty) = &expr.kind;
-            if let TyKind::Ptr(_) = ty.kind;
-            if let ExprKind::AddrOf(BorrowKind::Ref, mutability, e) = &left_expr.kind;
-
-            then {
-                let core_or_std = if is_no_std_crate(cx) { "core" } else { "std" };
-                let macro_name = match mutability {
-                    Mutability::Not => "addr_of",
-                    Mutability::Mut => "addr_of_mut",
-                };
-
-                span_lint_and_sugg(
-                    cx,
-                    BORROW_AS_PTR,
-                    expr.span,
-                    "borrow as raw pointer",
-                    "try",
-                    format!(
-                        "{}::ptr::{}!({})",
-                        core_or_std,
-                        macro_name,
-                        snippet_opt(cx, e.span).unwrap()
-                    ),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
-    }
-
-    extract_msrv_attr!(LateContext);
-}
diff --git a/src/tools/clippy/clippy_lints/src/borrow_deref_ref.rs b/src/tools/clippy/clippy_lints/src/borrow_deref_ref.rs
index 937765b66147..c4520d003928 100644
--- a/src/tools/clippy/clippy_lints/src/borrow_deref_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/borrow_deref_ref.rs
@@ -29,22 +29,17 @@ declare_clippy_lint! {
     ///
     /// ### Example
     /// ```rust
-    /// fn foo(_x: &str) {}
-    ///
     /// let s = &String::new();
     ///
     /// let a: &String = &* s;
-    /// foo(&*s);
     /// ```
     ///
     /// Use instead:
     /// ```rust
-    /// # fn foo(_x: &str) {}
     /// # let s = &String::new();
     /// let a: &String = s;
-    /// foo(&**s);
     /// ```
-    #[clippy::version = "1.59.0"]
+    #[clippy::version = "1.63.0"]
     pub BORROW_DEREF_REF,
     complexity,
     "deref on an immutable reference returns the same type as itself"
diff --git a/src/tools/clippy/clippy_lints/src/bytecount.rs b/src/tools/clippy/clippy_lints/src/bytecount.rs
deleted file mode 100644
index 326ce34082af..000000000000
--- a/src/tools/clippy/clippy_lints/src/bytecount.rs
+++ /dev/null
@@ -1,103 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::match_type;
-use clippy_utils::visitors::is_local_used;
-use clippy_utils::{path_to_local_id, paths, peel_blocks, peel_ref_operators, strip_pat_refs};
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir::{BinOpKind, Closure, Expr, ExprKind, PatKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, UintTy};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for naive byte counts
-    ///
-    /// ### Why is this bad?
-    /// The [`bytecount`](https://crates.io/crates/bytecount)
-    /// crate has methods to count your bytes faster, especially for large slices.
-    ///
-    /// ### Known problems
-    /// If you have predominantly small slices, the
-    /// `bytecount::count(..)` method may actually be slower. However, if you can
-    /// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
-    /// faster in those cases.
-    ///
-    /// ### Example
-    /// ```rust
-    /// # let vec = vec![1_u8];
-    /// let count = vec.iter().filter(|x| **x == 0u8).count();
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// # let vec = vec![1_u8];
-    /// let count = bytecount::count(&vec, 0u8);
-    /// ```
-    #[clippy::version = "pre 1.29.0"]
-    pub NAIVE_BYTECOUNT,
-    pedantic,
-    "use of naive `<slice>.filter(|&x| x == y).count()` to count byte values"
-}
-
-declare_lint_pass!(ByteCount => [NAIVE_BYTECOUNT]);
-
-impl<'tcx> LateLintPass<'tcx> for ByteCount {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if_chain! {
-            if let ExprKind::MethodCall(count, [count_recv], _) = expr.kind;
-            if count.ident.name == sym::count;
-            if let ExprKind::MethodCall(filter, [filter_recv, filter_arg], _) = count_recv.kind;
-            if filter.ident.name == sym!(filter);
-            if let ExprKind::Closure(&Closure { body, .. }) = filter_arg.kind;
-            let body = cx.tcx.hir().body(body);
-            if let [param] = body.params;
-            if let PatKind::Binding(_, arg_id, _, _) = strip_pat_refs(param.pat).kind;
-            if let ExprKind::Binary(ref op, l, r) = body.value.kind;
-            if op.node == BinOpKind::Eq;
-            if match_type(cx,
-                       cx.typeck_results().expr_ty(filter_recv).peel_refs(),
-                       &paths::SLICE_ITER);
-            let operand_is_arg = |expr| {
-                let expr = peel_ref_operators(cx, peel_blocks(expr));
-                path_to_local_id(expr, arg_id)
-            };
-            let needle = if operand_is_arg(l) {
-                r
-            } else if operand_is_arg(r) {
-                l
-            } else {
-                return;
-            };
-            if ty::Uint(UintTy::U8) == *cx.typeck_results().expr_ty(needle).peel_refs().kind();
-            if !is_local_used(cx, needle, arg_id);
-            then {
-                let haystack = if let ExprKind::MethodCall(path, args, _) =
-                        filter_recv.kind {
-                    let p = path.ident.name;
-                    if (p == sym::iter || p == sym!(iter_mut)) && args.len() == 1 {
-                        &args[0]
-                    } else {
-                        filter_recv
-                    }
-                } else {
-                    filter_recv
-                };
-                let mut applicability = Applicability::MaybeIncorrect;
-                span_lint_and_sugg(
-                    cx,
-                    NAIVE_BYTECOUNT,
-                    expr.span,
-                    "you appear to be counting bytes the naive way",
-                    "consider using the bytecount crate",
-                    format!("bytecount::count({}, {})",
-                            snippet_with_applicability(cx, haystack.span, "..", &mut applicability),
-                            snippet_with_applicability(cx, needle.span, "..", &mut applicability)),
-                    applicability,
-                );
-            }
-        };
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/bytes_count_to_len.rs b/src/tools/clippy/clippy_lints/src/bytes_count_to_len.rs
deleted file mode 100644
index d70dbf5b2390..000000000000
--- a/src/tools/clippy/clippy_lints/src/bytes_count_to_len.rs
+++ /dev/null
@@ -1,70 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::is_type_diagnostic_item;
-use clippy_utils::{match_def_path, paths};
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir as hir;
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// It checks for `str::bytes().count()` and suggests replacing it with
-    /// `str::len()`.
-    ///
-    /// ### Why is this bad?
-    /// `str::bytes().count()` is longer and may not be as performant as using
-    /// `str::len()`.
-    ///
-    /// ### Example
-    /// ```rust
-    /// "hello".bytes().count();
-    /// String::from("hello").bytes().count();
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// "hello".len();
-    /// String::from("hello").len();
-    /// ```
-    #[clippy::version = "1.62.0"]
-    pub BYTES_COUNT_TO_LEN,
-    complexity,
-    "Using `bytes().count()` when `len()` performs the same functionality"
-}
-
-declare_lint_pass!(BytesCountToLen => [BYTES_COUNT_TO_LEN]);
-
-impl<'tcx> LateLintPass<'tcx> for BytesCountToLen {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if_chain! {
-            if let hir::ExprKind::MethodCall(_, expr_args, _) = &expr.kind;
-            if let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
-            if match_def_path(cx, expr_def_id, &paths::ITER_COUNT);
-
-            if let [bytes_expr] = &**expr_args;
-            if let hir::ExprKind::MethodCall(_, bytes_args, _) = &bytes_expr.kind;
-            if let Some(bytes_def_id) = cx.typeck_results().type_dependent_def_id(bytes_expr.hir_id);
-            if match_def_path(cx, bytes_def_id, &paths::STR_BYTES);
-
-            if let [str_expr] = &**bytes_args;
-            let ty = cx.typeck_results().expr_ty(str_expr).peel_refs();
-
-            if is_type_diagnostic_item(cx, ty, sym::String) || ty.kind() == &ty::Str;
-            then {
-                let mut applicability = Applicability::MachineApplicable;
-                span_lint_and_sugg(
-                    cx,
-                    BYTES_COUNT_TO_LEN,
-                    expr.span,
-                    "using long and hard to read `.bytes().count()`",
-                    "consider calling `.len()` instead",
-                    format!("{}.len()", snippet_with_applicability(cx, str_expr.span, "..", &mut applicability)),
-                    applicability
-                );
-            }
-        };
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/case_sensitive_file_extension_comparisons.rs b/src/tools/clippy/clippy_lints/src/case_sensitive_file_extension_comparisons.rs
deleted file mode 100644
index 7eff71d50074..000000000000
--- a/src/tools/clippy/clippy_lints/src/case_sensitive_file_extension_comparisons.rs
+++ /dev/null
@@ -1,86 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_help;
-use if_chain::if_chain;
-use rustc_ast::ast::LitKind;
-use rustc_hir::{Expr, ExprKind, PathSegment};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::{source_map::Spanned, symbol::sym, Span};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for calls to `ends_with` with possible file extensions
-    /// and suggests to use a case-insensitive approach instead.
-    ///
-    /// ### Why is this bad?
-    /// `ends_with` is case-sensitive and may not detect files with a valid extension.
-    ///
-    /// ### Example
-    /// ```rust
-    /// fn is_rust_file(filename: &str) -> bool {
-    ///     filename.ends_with(".rs")
-    /// }
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// fn is_rust_file(filename: &str) -> bool {
-    ///     let filename = std::path::Path::new(filename);
-    ///     filename.extension()
-    ///         .map(|ext| ext.eq_ignore_ascii_case("rs"))
-    ///         .unwrap_or(false)
-    /// }
-    /// ```
-    #[clippy::version = "1.51.0"]
-    pub CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
-    pedantic,
-    "Checks for calls to ends_with with case-sensitive file extensions"
-}
-
-declare_lint_pass!(CaseSensitiveFileExtensionComparisons => [CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS]);
-
-fn check_case_sensitive_file_extension_comparison(ctx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Span> {
-    if_chain! {
-        if let ExprKind::MethodCall(PathSegment { ident, .. }, [obj, extension, ..], span) = expr.kind;
-        if ident.as_str() == "ends_with";
-        if let ExprKind::Lit(Spanned { node: LitKind::Str(ext_literal, ..), ..}) = extension.kind;
-        if (2..=6).contains(&ext_literal.as_str().len());
-        if ext_literal.as_str().starts_with('.');
-        if ext_literal.as_str().chars().skip(1).all(|c| c.is_uppercase() || c.is_ascii_digit())
-            || ext_literal.as_str().chars().skip(1).all(|c| c.is_lowercase() || c.is_ascii_digit());
-        then {
-            let mut ty = ctx.typeck_results().expr_ty(obj);
-            ty = match ty.kind() {
-                ty::Ref(_, ty, ..) => *ty,
-                _ => ty
-            };
-
-            match ty.kind() {
-                ty::Str => {
-                    return Some(span);
-                },
-                ty::Adt(def, _) => {
-                    if ctx.tcx.is_diagnostic_item(sym::String, def.did()) {
-                        return Some(span);
-                    }
-                },
-                _ => { return None; }
-            }
-        }
-    }
-    None
-}
-
-impl<'tcx> LateLintPass<'tcx> for CaseSensitiveFileExtensionComparisons {
-    fn check_expr(&mut self, ctx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        if let Some(span) = check_case_sensitive_file_extension_comparison(ctx, expr) {
-            span_lint_and_help(
-                ctx,
-                CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
-                span,
-                "case-sensitive file extension comparison",
-                None,
-                "consider using a case-insensitive comparison instead",
-            );
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/casts/as_underscore.rs b/src/tools/clippy/clippy_lints/src/casts/as_underscore.rs
new file mode 100644
index 000000000000..56e894c6261e
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/casts/as_underscore.rs
@@ -0,0 +1,25 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, Ty, TyKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty;
+
+use super::AS_UNDERSCORE;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ty: &'tcx Ty<'_>) {
+    if matches!(ty.kind, TyKind::Infer) {
+        span_lint_and_then(cx, AS_UNDERSCORE, expr.span, "using `as _` conversion", |diag| {
+            let ty_resolved = cx.typeck_results().expr_ty(expr);
+            if let ty::Error(_) = ty_resolved.kind() {
+                diag.help("consider giving the type explicitly");
+            } else {
+                diag.span_suggestion(
+                    ty.span,
+                    "consider giving the type explicitly",
+                    ty_resolved,
+                    Applicability::MachineApplicable,
+                );
+            }
+        });
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/casts/borrow_as_ptr.rs b/src/tools/clippy/clippy_lints/src/casts/borrow_as_ptr.rs
new file mode 100644
index 000000000000..6e1f8cd64f07
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/casts/borrow_as_ptr.rs
@@ -0,0 +1,37 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_no_std_crate;
+use clippy_utils::source::snippet_with_context;
+use rustc_errors::Applicability;
+use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, Ty, TyKind};
+use rustc_lint::LateContext;
+
+use super::BORROW_AS_PTR;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    cast_expr: &'tcx Expr<'_>,
+    cast_to: &'tcx Ty<'_>,
+) {
+    if matches!(cast_to.kind, TyKind::Ptr(_))
+        && let ExprKind::AddrOf(BorrowKind::Ref, mutability, e) = cast_expr.kind
+    {
+        let core_or_std = if is_no_std_crate(cx) { "core" } else { "std" };
+        let macro_name = match mutability {
+            Mutability::Not => "addr_of",
+            Mutability::Mut => "addr_of_mut",
+        };
+        let mut app = Applicability::MachineApplicable;
+        let snip = snippet_with_context(cx, e.span, cast_expr.span.ctxt(), "..", &mut app).0;
+
+        span_lint_and_sugg(
+            cx,
+            BORROW_AS_PTR,
+            expr.span,
+            "borrow as raw pointer",
+            "try",
+            format!("{}::ptr::{}!({})", core_or_std, macro_name, snip),
+            Applicability::MachineApplicable,
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs b/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs
index 6426e8c25ac1..3f1edabe6c50 100644
--- a/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs
@@ -20,7 +20,7 @@ pub(super) fn check(
     if meets_msrv(msrv, msrvs::UNSIGNED_ABS)
         && let ty::Int(from) = cast_from.kind()
         && let ty::Uint(to) = cast_to.kind()
-        && let ExprKind::MethodCall(method_path, args, _) = cast_expr.kind
+        && let ExprKind::MethodCall(method_path, receiver, ..) = cast_expr.kind
         && method_path.ident.name.as_str() == "abs"
     {
         let span = if from.bit_width() == to.bit_width() {
@@ -37,7 +37,7 @@ pub(super) fn check(
             span,
             &format!("casting the result of `{cast_from}::abs()` to {cast_to}"),
             "replace with",
-            format!("{}.unsigned_abs()", Sugg::hir(cx, &args[0], "..").maybe_par()),
+            format!("{}.unsigned_abs()", Sugg::hir(cx, receiver, "..").maybe_par()),
             Applicability::MachineApplicable,
         );
     }
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_possible_truncation.rs b/src/tools/clippy/clippy_lints/src/casts/cast_possible_truncation.rs
index 64f87c80f8d1..406547a4454e 100644
--- a/src/tools/clippy/clippy_lints/src/casts/cast_possible_truncation.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_possible_truncation.rs
@@ -44,7 +44,7 @@ fn apply_reductions(cx: &LateContext<'_>, nbits: u64, expr: &Expr<'_>, signed: b
                 .saturating_sub(constant_int(cx, right).map_or(0, |s| u64::try_from(s).expect("shift too high"))),
             _ => nbits,
         },
-        ExprKind::MethodCall(method, [left, right], _) => {
+        ExprKind::MethodCall(method, left, [right], _) => {
             if signed {
                 return nbits;
             }
@@ -55,7 +55,7 @@ fn apply_reductions(cx: &LateContext<'_>, nbits: u64, expr: &Expr<'_>, signed: b
             };
             apply_reductions(cx, nbits, left, signed).min(max_bits.unwrap_or(u64::max_value()))
         },
-        ExprKind::MethodCall(method, [_, lo, hi], _) => {
+        ExprKind::MethodCall(method, _, [lo, hi], _) => {
             if method.ident.as_str() == "clamp" {
                 //FIXME: make this a diagnostic item
                 if let (Some(lo_bits), Some(hi_bits)) = (get_constant_bits(cx, lo), get_constant_bits(cx, hi)) {
@@ -64,7 +64,7 @@ fn apply_reductions(cx: &LateContext<'_>, nbits: u64, expr: &Expr<'_>, signed: b
             }
             nbits
         },
-        ExprKind::MethodCall(method, [_value], _) => {
+        ExprKind::MethodCall(method, _value, [], _) => {
             if method.ident.name.as_str() == "signum" {
                 0 // do not lint if cast comes from a `signum` function
             } else {
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_ptr_alignment.rs b/src/tools/clippy/clippy_lints/src/casts/cast_ptr_alignment.rs
index d476a1a7646c..da7b12f67266 100644
--- a/src/tools/clippy/clippy_lints/src/casts/cast_ptr_alignment.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_ptr_alignment.rs
@@ -18,7 +18,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
             cx.typeck_results().expr_ty(expr),
         );
         lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
-    } else if let ExprKind::MethodCall(method_path, [self_arg, ..], _) = &expr.kind {
+    } else if let ExprKind::MethodCall(method_path, self_arg, ..) = &expr.kind {
         if method_path.ident.name == sym!(cast)
             && let Some(generic_args) = method_path.args
             && let [GenericArg::Type(cast_to)] = generic_args.args
@@ -64,7 +64,7 @@ fn is_used_as_unaligned(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
         return false;
     };
     match parent.kind {
-        ExprKind::MethodCall(name, [self_arg, ..], _) if self_arg.hir_id == e.hir_id => {
+        ExprKind::MethodCall(name, self_arg, ..) if self_arg.hir_id == e.hir_id => {
             if matches!(name.ident.as_str(), "read_unaligned" | "write_unaligned")
                 && let Some(def_id) = cx.typeck_results().type_dependent_def_id(parent.hir_id)
                 && let Some(def_id) = cx.tcx.impl_of_method(def_id)
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_sign_loss.rs b/src/tools/clippy/clippy_lints/src/casts/cast_sign_loss.rs
index 75f70b77ed4e..5b59350be042 100644
--- a/src/tools/clippy/clippy_lints/src/casts/cast_sign_loss.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_sign_loss.rs
@@ -41,14 +41,14 @@ fn should_lint(cx: &LateContext<'_>, cast_op: &Expr<'_>, cast_from: Ty<'_>, cast
             }
 
             // Don't lint for the result of methods that always return non-negative values.
-            if let ExprKind::MethodCall(path, _, _) = cast_op.kind {
+            if let ExprKind::MethodCall(path, ..) = cast_op.kind {
                 let mut method_name = path.ident.name.as_str();
                 let allowed_methods = ["abs", "checked_abs", "rem_euclid", "checked_rem_euclid"];
 
                 if_chain! {
                     if method_name == "unwrap";
                     if let Some(arglist) = method_chain_args(cast_op, &["unwrap"]);
-                    if let ExprKind::MethodCall(inner_path, _, _) = &arglist[0][0].kind;
+                    if let ExprKind::MethodCall(inner_path, ..) = &arglist[0].0.kind;
                     then {
                         method_name = inner_path.ident.name.as_str();
                     }
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_slice_from_raw_parts.rs b/src/tools/clippy/clippy_lints/src/casts/cast_slice_from_raw_parts.rs
new file mode 100644
index 000000000000..284ef165998a
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_slice_from_raw_parts.rs
@@ -0,0 +1,63 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::{match_def_path, meets_msrv, msrvs, paths};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::{def_id::DefId, Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self, Ty};
+use rustc_semver::RustcVersion;
+
+use super::CAST_SLICE_FROM_RAW_PARTS;
+
+enum RawPartsKind {
+    Immutable,
+    Mutable,
+}
+
+fn raw_parts_kind(cx: &LateContext<'_>, did: DefId) -> Option<RawPartsKind> {
+    if match_def_path(cx, did, &paths::SLICE_FROM_RAW_PARTS) {
+        Some(RawPartsKind::Immutable)
+    } else if match_def_path(cx, did, &paths::SLICE_FROM_RAW_PARTS_MUT) {
+        Some(RawPartsKind::Mutable)
+    } else {
+        None
+    }
+}
+
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    cast_expr: &Expr<'_>,
+    cast_to: Ty<'_>,
+    msrv: Option<RustcVersion>,
+) {
+    if_chain! {
+        if meets_msrv(msrv, msrvs::PTR_SLICE_RAW_PARTS);
+        if let ty::RawPtr(ptrty) = cast_to.kind();
+        if let ty::Slice(_) = ptrty.ty.kind();
+        if let ExprKind::Call(fun, [ptr_arg, len_arg]) = cast_expr.peel_blocks().kind;
+        if let ExprKind::Path(ref qpath) = fun.kind;
+        if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
+        if let Some(rpk) = raw_parts_kind(cx, fun_def_id);
+        then {
+            let func = match rpk {
+                RawPartsKind::Immutable => "from_raw_parts",
+                RawPartsKind::Mutable => "from_raw_parts_mut"
+            };
+            let span = expr.span;
+            let mut applicability = Applicability::MachineApplicable;
+            let ptr = snippet_with_applicability(cx, ptr_arg.span, "ptr", &mut applicability);
+            let len = snippet_with_applicability(cx, len_arg.span, "len", &mut applicability);
+            span_lint_and_sugg(
+                cx,
+                CAST_SLICE_FROM_RAW_PARTS,
+                span,
+                &format!("casting the result of `{func}` to {cast_to}"),
+                "replace with",
+                format!("core::ptr::slice_{func}({ptr}, {len})"),
+                applicability
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/casts/mod.rs b/src/tools/clippy/clippy_lints/src/casts/mod.rs
index af3798a0cc8c..cc5d346b954e 100644
--- a/src/tools/clippy/clippy_lints/src/casts/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/mod.rs
@@ -1,3 +1,5 @@
+mod as_underscore;
+mod borrow_as_ptr;
 mod cast_abs_to_unsigned;
 mod cast_enum_constructor;
 mod cast_lossless;
@@ -8,6 +10,7 @@ mod cast_ptr_alignment;
 mod cast_ref_to_mut;
 mod cast_sign_loss;
 mod cast_slice_different_sizes;
+mod cast_slice_from_raw_parts;
 mod char_lit_as_u8;
 mod fn_to_numeric_cast;
 mod fn_to_numeric_cast_any;
@@ -16,7 +19,7 @@ mod ptr_as_ptr;
 mod unnecessary_cast;
 mod utils;
 
-use clippy_utils::is_hir_ty_cfg_dependant;
+use clippy_utils::{is_hir_ty_cfg_dependant, meets_msrv, msrvs};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
@@ -506,6 +509,93 @@ declare_clippy_lint! {
     "casting the result of `abs()` to an unsigned integer can panic"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Check for the usage of `as _` conversion using inferred type.
+    ///
+    /// ### Why is this bad?
+    /// The conversion might include lossy conversion and dangerous cast that might go
+    /// undetected due to the type being inferred.
+    ///
+    /// The lint is allowed by default as using `_` is less wordy than always specifying the type.
+    ///
+    /// ### Example
+    /// ```rust
+    /// fn foo(n: usize) {}
+    /// let n: u16 = 256;
+    /// foo(n as _);
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// fn foo(n: usize) {}
+    /// let n: u16 = 256;
+    /// foo(n as usize);
+    /// ```
+    #[clippy::version = "1.63.0"]
+    pub AS_UNDERSCORE,
+    restriction,
+    "detects `as _` conversion"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for the usage of `&expr as *const T` or
+    /// `&mut expr as *mut T`, and suggest using `ptr::addr_of` or
+    /// `ptr::addr_of_mut` instead.
+    ///
+    /// ### Why is this bad?
+    /// This would improve readability and avoid creating a reference
+    /// that points to an uninitialized value or unaligned place.
+    /// Read the `ptr::addr_of` docs for more information.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let val = 1;
+    /// let p = &val as *const i32;
+    ///
+    /// let mut val_mut = 1;
+    /// let p_mut = &mut val_mut as *mut i32;
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// let val = 1;
+    /// let p = std::ptr::addr_of!(val);
+    ///
+    /// let mut val_mut = 1;
+    /// let p_mut = std::ptr::addr_of_mut!(val_mut);
+    /// ```
+    #[clippy::version = "1.60.0"]
+    pub BORROW_AS_PTR,
+    pedantic,
+    "borrowing just to cast to a raw pointer"
+}
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for a raw slice being cast to a slice pointer
+    ///
+    /// ### Why is this bad?
+    /// This can result in multiple `&mut` references to the same location when only a pointer is
+    /// required.
+    /// `ptr::slice_from_raw_parts` is a safe alternative that doesn't require
+    /// the same [safety requirements] to be upheld.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// let _: *const [u8] = std::slice::from_raw_parts(ptr, len) as *const _;
+    /// let _: *mut [u8] = std::slice::from_raw_parts_mut(ptr, len) as *mut _;
+    /// ```
+    /// Use instead:
+    /// ```rust,ignore
+    /// let _: *const [u8] = std::ptr::slice_from_raw_parts(ptr, len);
+    /// let _: *mut [u8] = std::ptr::slice_from_raw_parts_mut(ptr, len);
+    /// ```
+    /// [safety requirements]: https://doc.rust-lang.org/std/slice/fn.from_raw_parts.html#safety
+    #[clippy::version = "1.64.0"]
+    pub CAST_SLICE_FROM_RAW_PARTS,
+    suspicious,
+    "casting a slice created from a pointer and length to a slice pointer"
+}
+
 pub struct Casts {
     msrv: Option<RustcVersion>,
 }
@@ -534,7 +624,10 @@ impl_lint_pass!(Casts => [
     PTR_AS_PTR,
     CAST_ENUM_TRUNCATION,
     CAST_ENUM_CONSTRUCTOR,
-    CAST_ABS_TO_UNSIGNED
+    CAST_ABS_TO_UNSIGNED,
+    AS_UNDERSCORE,
+    BORROW_AS_PTR,
+    CAST_SLICE_FROM_RAW_PARTS
 ]);
 
 impl<'tcx> LateLintPass<'tcx> for Casts {
@@ -547,8 +640,8 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             return;
         }
 
-        if let ExprKind::Cast(cast_expr, cast_to) = expr.kind {
-            if is_hir_ty_cfg_dependant(cx, cast_to) {
+        if let ExprKind::Cast(cast_expr, cast_to_hir) = expr.kind {
+            if is_hir_ty_cfg_dependant(cx, cast_to_hir) {
                 return;
             }
             let (cast_from, cast_to) = (
@@ -559,7 +652,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             if unnecessary_cast::check(cx, expr, cast_expr, cast_from, cast_to) {
                 return;
             }
-
+            cast_slice_from_raw_parts::check(cx, expr, cast_expr, cast_to, self.msrv);
             fn_to_numeric_cast_any::check(cx, expr, cast_expr, cast_from, cast_to);
             fn_to_numeric_cast::check(cx, expr, cast_expr, cast_from, cast_to);
             fn_to_numeric_cast_with_truncation::check(cx, expr, cast_expr, cast_from, cast_to);
@@ -575,6 +668,12 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
                 cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to, self.msrv);
                 cast_enum_constructor::check(cx, expr, cast_expr, cast_from);
             }
+
+            as_underscore::check(cx, expr, cast_to_hir);
+
+            if meets_msrv(self.msrv, msrvs::BORROW_AS_PTR) {
+                borrow_as_ptr::check(cx, expr, cast_expr, cast_to_hir);
+            }
         }
 
         cast_ref_to_mut::check(cx, expr);
diff --git a/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs b/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
index fff7da8e33f2..19d2e6e1d129 100644
--- a/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
@@ -90,13 +90,20 @@ pub(super) fn check<'tcx>(
 
 fn lint_unnecessary_cast(cx: &LateContext<'_>, expr: &Expr<'_>, literal_str: &str, cast_from: Ty<'_>, cast_to: Ty<'_>) {
     let literal_kind_name = if cast_from.is_integral() { "integer" } else { "float" };
+    let replaced_literal;
+    let matchless = if literal_str.contains(['(', ')']) {
+        replaced_literal = literal_str.replace(['(', ')'], "");
+        &replaced_literal
+    } else {
+        literal_str
+    };
     span_lint_and_sugg(
         cx,
         UNNECESSARY_CAST,
         expr.span,
         &format!("casting {} literal to `{}` is unnecessary", literal_kind_name, cast_to),
         "try",
-        format!("{}_{}", literal_str.trim_end_matches('.'), cast_to),
+        format!("{}_{}", matchless.trim_end_matches('.'), cast_to),
         Applicability::MachineApplicable,
     );
 }
diff --git a/src/tools/clippy/clippy_lints/src/default.rs b/src/tools/clippy/clippy_lints/src/default.rs
index 74f7df611778..4e68d6810e29 100644
--- a/src/tools/clippy/clippy_lints/src/default.rs
+++ b/src/tools/clippy/clippy_lints/src/default.rs
@@ -142,7 +142,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
                 if adt.is_struct();
                 let variant = adt.non_enum_variant();
                 if adt.did().is_local() || !variant.is_field_list_non_exhaustive();
-                let module_did = cx.tcx.parent_module(stmt.hir_id).to_def_id();
+                let module_did = cx.tcx.parent_module(stmt.hir_id);
                 if variant
                     .fields
                     .iter()
diff --git a/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs b/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs
index fb418a3251f5..be02f328e989 100644
--- a/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs
+++ b/src/tools/clippy/clippy_lints/src/default_numeric_fallback.rs
@@ -131,10 +131,10 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
                 }
             },
 
-            ExprKind::MethodCall(_, args, _) => {
+            ExprKind::MethodCall(_, receiver, args, _) => {
                 if let Some(def_id) = self.cx.typeck_results().type_dependent_def_id(expr.hir_id) {
                     let fn_sig = self.cx.tcx.fn_sig(def_id).skip_binder();
-                    for (expr, bound) in iter::zip(*args, fn_sig.inputs()) {
+                    for (expr, bound) in iter::zip(std::iter::once(*receiver).chain(args.iter()), fn_sig.inputs()) {
                         self.ty_bounds.push(TyBound::Ty(*bound));
                         self.visit_expr(expr);
                         self.ty_bounds.pop();
diff --git a/src/tools/clippy/clippy_lints/src/dereference.rs b/src/tools/clippy/clippy_lints/src/dereference.rs
index 59f10247a11d..e54d71fc8e41 100644
--- a/src/tools/clippy/clippy_lints/src/dereference.rs
+++ b/src/tools/clippy/clippy_lints/src/dereference.rs
@@ -1,24 +1,34 @@
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
 use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
 use clippy_utils::sugg::has_enclosing_paren;
-use clippy_utils::ty::{expr_sig, peel_mid_ty_refs, ty_sig, variant_of_res};
-use clippy_utils::{get_parent_expr, get_parent_expr_for_hir, is_lint_allowed, path_to_local, walk_to_expr_usage};
+use clippy_utils::ty::{expr_sig, is_copy, peel_mid_ty_refs, ty_sig, variant_of_res};
+use clippy_utils::{
+    fn_def_id, get_parent_expr, get_parent_expr_for_hir, is_lint_allowed, meets_msrv, msrvs, path_to_local,
+    walk_to_expr_usage,
+};
 use rustc_ast::util::parser::{PREC_POSTFIX, PREC_PREFIX};
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_ty, Visitor};
 use rustc_hir::{
-    self as hir, BindingAnnotation, Body, BodyId, BorrowKind, Closure, Expr, ExprKind, FnRetTy, GenericArg, HirId,
-    ImplItem, ImplItemKind, Item, ItemKind, Local, MatchSource, Mutability, Node, Pat, PatKind, Path, QPath, TraitItem,
-    TraitItemKind, TyKind, UnOp,
+    self as hir, def_id::DefId, BindingAnnotation, Body, BodyId, BorrowKind, Closure, Expr, ExprKind, FnRetTy,
+    GenericArg, HirId, ImplItem, ImplItemKind, Item, ItemKind, Local, MatchSource, Mutability, Node, Pat, PatKind,
+    Path, QPath, TraitItem, TraitItemKind, TyKind, UnOp,
 };
+use rustc_index::bit_set::BitSet;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
-use rustc_middle::ty::{self, Binder, BoundVariableKind, List, Ty, TyCtxt, TypeVisitable, TypeckResults};
+use rustc_middle::ty::{
+    self, Binder, BoundVariableKind, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
+    ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
+};
+use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{symbol::sym, Span, Symbol, DUMMY_SP};
-use rustc_trait_selection::infer::InferCtxtExt;
+use rustc_trait_selection::infer::InferCtxtExt as _;
+use rustc_trait_selection::traits::{query::evaluate_obligation::InferCtxtExt as _, Obligation, ObligationCause};
+use std::collections::VecDeque;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -151,6 +161,7 @@ pub struct Dereferencing {
     /// been finished. Note we can't lint at the end of every body as they can be nested within each
     /// other.
     current_body: Option<BodyId>,
+
     /// The list of locals currently being checked by the lint.
     /// If the value is `None`, then the binding has been seen as a ref pattern, but is not linted.
     /// This is needed for or patterns where one of the branches can be linted, but another can not
@@ -158,6 +169,19 @@ pub struct Dereferencing {
     ///
     /// e.g. `m!(x) | Foo::Bar(ref x)`
     ref_locals: FxIndexMap<HirId, Option<RefPat>>,
+
+    // `IntoIterator` for arrays requires Rust 1.53.
+    msrv: Option<RustcVersion>,
+}
+
+impl Dereferencing {
+    #[must_use]
+    pub fn new(msrv: Option<RustcVersion>) -> Self {
+        Self {
+            msrv,
+            ..Dereferencing::default()
+        }
+    }
 }
 
 struct StateData {
@@ -170,6 +194,7 @@ struct StateData {
 struct DerefedBorrow {
     count: usize,
     msg: &'static str,
+    snip_expr: Option<HirId>,
 }
 
 enum State {
@@ -250,7 +275,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
         match (self.state.take(), kind) {
             (None, kind) => {
                 let expr_ty = typeck.expr_ty(expr);
-                let (position, adjustments) = walk_parents(cx, expr);
+                let (position, adjustments) = walk_parents(cx, expr, self.msrv);
 
                 match kind {
                     RefOp::Deref => {
@@ -272,13 +297,10 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                         if !is_lint_allowed(cx, EXPLICIT_DEREF_METHODS, expr.hir_id)
                             && position.lint_explicit_deref() =>
                     {
+                        let ty_changed_count = usize::from(!deref_method_same_type(expr_ty, typeck.expr_ty(sub_expr)));
                         self.state = Some((
                             State::DerefMethod {
-                                ty_changed_count: if deref_method_same_type(expr_ty, typeck.expr_ty(sub_expr)) {
-                                    0
-                                } else {
-                                    1
-                                },
+                                ty_changed_count,
                                 is_final_ufcs: matches!(expr.kind, ExprKind::Call(..)),
                                 target_mut,
                             },
@@ -331,20 +353,23 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                         let deref_msg =
                             "this expression creates a reference which is immediately dereferenced by the compiler";
                         let borrow_msg = "this expression borrows a value the compiler would automatically borrow";
+                        let impl_msg = "the borrowed expression implements the required traits";
 
-                        let (required_refs, msg) = if position.can_auto_borrow() {
-                            (1, if deref_count == 1 { borrow_msg } else { deref_msg })
+                        let (required_refs, msg, snip_expr) = if position.can_auto_borrow() {
+                            (1, if deref_count == 1 { borrow_msg } else { deref_msg }, None)
+                        } else if let Position::ImplArg(hir_id) = position {
+                            (0, impl_msg, Some(hir_id))
                         } else if let Some(&Adjust::Borrow(AutoBorrow::Ref(_, mutability))) =
                             next_adjust.map(|a| &a.kind)
                         {
                             if matches!(mutability, AutoBorrowMutability::Mut { .. }) && !position.is_reborrow_stable()
                             {
-                                (3, deref_msg)
+                                (3, deref_msg, None)
                             } else {
-                                (2, deref_msg)
+                                (2, deref_msg, None)
                             }
                         } else {
-                            (2, deref_msg)
+                            (2, deref_msg, None)
                         };
 
                         if deref_count >= required_refs {
@@ -354,6 +379,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                                     // can't be removed without breaking the code. See earlier comment.
                                     count: deref_count - required_refs,
                                     msg,
+                                    snip_expr,
                                 }),
                                 StateData { span: expr.span, hir_id: expr.hir_id, position },
                             ));
@@ -474,7 +500,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
     }
 
     fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
-        if let PatKind::Binding(BindingAnnotation::Ref, id, name, _) = pat.kind {
+        if let PatKind::Binding(BindingAnnotation::REF, id, name, _) = pat.kind {
             if let Some(opt_prev_pat) = self.ref_locals.get_mut(&id) {
                 // This binding id has been seen before. Add this pattern to the list of changes.
                 if let Some(prev_pat) = opt_prev_pat {
@@ -510,7 +536,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                             spans: vec![pat.span],
                             app,
                             replacements: vec![(pat.span, snip.into())],
-                            hir_id: pat.hir_id
+                            hir_id: pat.hir_id,
                         }),
                     );
                 }
@@ -542,6 +568,8 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
             self.current_body = None;
         }
     }
+
+    extract_msrv_attr!(LateContext);
 }
 
 fn try_parse_ref_op<'tcx>(
@@ -550,7 +578,7 @@ fn try_parse_ref_op<'tcx>(
     expr: &'tcx Expr<'_>,
 ) -> Option<(RefOp, &'tcx Expr<'tcx>)> {
     let (def_id, arg) = match expr.kind {
-        ExprKind::MethodCall(_, [arg], _) => (typeck.type_dependent_def_id(expr.hir_id)?, arg),
+        ExprKind::MethodCall(_, arg, [], _) => (typeck.type_dependent_def_id(expr.hir_id)?, arg),
         ExprKind::Call(
             Expr {
                 kind: ExprKind::Path(path),
@@ -594,6 +622,7 @@ enum Position {
     /// The method is defined on a reference type. e.g. `impl Foo for &T`
     MethodReceiverRefImpl,
     Callee,
+    ImplArg(HirId),
     FieldAccess(Symbol),
     Postfix,
     Deref,
@@ -630,7 +659,7 @@ impl Position {
             | Self::Callee
             | Self::FieldAccess(_)
             | Self::Postfix => PREC_POSTFIX,
-            Self::Deref => PREC_PREFIX,
+            Self::ImplArg(_) | Self::Deref => PREC_PREFIX,
             Self::DerefStable(p, _) | Self::ReborrowStable(p) | Self::Other(p) => p,
         }
     }
@@ -639,8 +668,12 @@ impl Position {
 /// Walks up the parent expressions attempting to determine both how stable the auto-deref result
 /// is, and which adjustments will be applied to it. Note this will not consider auto-borrow
 /// locations as those follow different rules.
-#[allow(clippy::too_many_lines)]
-fn walk_parents<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> (Position, &'tcx [Adjustment<'tcx>]) {
+#[expect(clippy::too_many_lines)]
+fn walk_parents<'tcx>(
+    cx: &LateContext<'tcx>,
+    e: &'tcx Expr<'_>,
+    msrv: Option<RustcVersion>,
+) -> (Position, &'tcx [Adjustment<'tcx>]) {
     let mut adjustments = [].as_slice();
     let mut precedence = 0i8;
     let ctxt = e.span.ctxt();
@@ -671,7 +704,7 @@ fn walk_parents<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> (Position, &
                 span,
                 ..
             }) if span.ctxt() == ctxt => {
-                let ty = cx.tcx.type_of(def_id);
+                let ty = cx.tcx.type_of(def_id.def_id);
                 Some(ty_auto_deref_stability(cx, ty, precedence).position_for_result(cx))
             },
 
@@ -745,56 +778,66 @@ fn walk_parents<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> (Position, &
                     .iter()
                     .position(|arg| arg.hir_id == child_id)
                     .zip(expr_sig(cx, func))
-                    .and_then(|(i, sig)| sig.input_with_hir(i))
-                    .map(|(hir_ty, ty)| match hir_ty {
-                        // Type inference for closures can depend on how they're called. Only go by the explicit
-                        // types here.
-                        Some(hir_ty) => binding_ty_auto_deref_stability(cx, hir_ty, precedence, ty.bound_vars()),
-                        None => ty_auto_deref_stability(cx, cx.tcx.erase_late_bound_regions(ty), precedence)
-                            .position_for_arg(),
-                    }),
-                ExprKind::MethodCall(_, args, _) => {
-                    let id = cx.typeck_results().type_dependent_def_id(parent.hir_id).unwrap();
-                    args.iter().position(|arg| arg.hir_id == child_id).map(|i| {
-                        if i == 0 {
-                            // Check for calls to trait methods where the trait is implemented on a reference.
-                            // Two cases need to be handled:
-                            // * `self` methods on `&T` will never have auto-borrow
-                            // * `&self` methods on `&T` can have auto-borrow, but `&self` methods on `T` will take
-                            //   priority.
-                            if e.hir_id != child_id {
-                                Position::ReborrowStable(precedence)
-                            } else if let Some(trait_id) = cx.tcx.trait_of_item(id)
-                                && let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
-                                && let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
-                                && let subs = match cx
-                                    .typeck_results()
-                                    .node_substs_opt(parent.hir_id)
-                                    .and_then(|subs| subs.get(1..))
-                                {
-                                    Some(subs) => cx.tcx.mk_substs(subs.iter().copied()),
-                                    None => cx.tcx.mk_substs([].iter()),
-                                } && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
-                                    // Trait methods taking `&self`
-                                    sub_ty
+                    .and_then(|(i, sig)| {
+                        sig.input_with_hir(i).map(|(hir_ty, ty)| match hir_ty {
+                            // Type inference for closures can depend on how they're called. Only go by the explicit
+                            // types here.
+                            Some(hir_ty) => binding_ty_auto_deref_stability(cx, hir_ty, precedence, ty.bound_vars()),
+                            None => {
+                                if let ty::Param(param_ty) = ty.skip_binder().kind() {
+                                    needless_borrow_impl_arg_position(cx, parent, i, *param_ty, e, precedence, msrv)
                                 } else {
-                                    // Trait methods taking `self`
-                                    arg_ty
-                                } && impl_ty.is_ref()
-                                && cx.tcx.infer_ctxt().enter(|infcx|
-                                    infcx
-                                        .type_implements_trait(trait_id, impl_ty, subs, cx.param_env)
-                                        .must_apply_modulo_regions()
-                                )
+                                    ty_auto_deref_stability(cx, cx.tcx.erase_late_bound_regions(ty), precedence)
+                                        .position_for_arg()
+                                }
+                            },
+                        })
+                    }),
+                ExprKind::MethodCall(_, receiver, args, _) => {
+                    let id = cx.typeck_results().type_dependent_def_id(parent.hir_id).unwrap();
+                    if receiver.hir_id == child_id {
+                        // Check for calls to trait methods where the trait is implemented on a reference.
+                        // Two cases need to be handled:
+                        // * `self` methods on `&T` will never have auto-borrow
+                        // * `&self` methods on `&T` can have auto-borrow, but `&self` methods on `T` will take
+                        //   priority.
+                        if e.hir_id != child_id {
+                            return Some(Position::ReborrowStable(precedence))
+                        } else if let Some(trait_id) = cx.tcx.trait_of_item(id)
+                            && let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
+                            && let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
+                            && let subs = match cx
+                                .typeck_results()
+                                .node_substs_opt(parent.hir_id)
+                                .and_then(|subs| subs.get(1..))
                             {
-                                Position::MethodReceiverRefImpl
+                                Some(subs) => cx.tcx.mk_substs(subs.iter().copied()),
+                                None => cx.tcx.mk_substs(std::iter::empty::<ty::subst::GenericArg<'_>>()),
+                            } && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
+                                // Trait methods taking `&self`
+                                sub_ty
                             } else {
-                                Position::MethodReceiver
-                            }
+                                // Trait methods taking `self`
+                                arg_ty
+                            } && impl_ty.is_ref()
+                            && cx.tcx.infer_ctxt().enter(|infcx|
+                                infcx
+                                    .type_implements_trait(trait_id, impl_ty, subs, cx.param_env)
+                                    .must_apply_modulo_regions()
+                            )
+                        {
+                            return Some(Position::MethodReceiverRefImpl)
+                        }
+                        return Some(Position::MethodReceiver);
+                    }
+                    args.iter().position(|arg| arg.hir_id == child_id).map(|i| {
+                        let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i + 1];
+                        if let ty::Param(param_ty) = ty.kind() {
+                            needless_borrow_impl_arg_position(cx, parent, i + 1, *param_ty, e, precedence, msrv)
                         } else {
                             ty_auto_deref_stability(
                                 cx,
-                                cx.tcx.erase_late_bound_regions(cx.tcx.fn_sig(id).input(i)),
+                                cx.tcx.erase_late_bound_regions(cx.tcx.fn_sig(id).input(i + 1)),
                                 precedence,
                             )
                             .position_for_arg()
@@ -948,6 +991,205 @@ fn ty_contains_infer(ty: &hir::Ty<'_>) -> bool {
     v.0
 }
 
+// Checks whether:
+// * child is an expression of the form `&e` in an argument position requiring an `impl Trait`
+// * `e`'s type implements `Trait` and is copyable
+// If the conditions are met, returns `Some(Position::ImplArg(..))`; otherwise, returns `None`.
+//   The "is copyable" condition is to avoid the case where removing the `&` means `e` would have to
+// be moved, but it cannot be.
+fn needless_borrow_impl_arg_position<'tcx>(
+    cx: &LateContext<'tcx>,
+    parent: &Expr<'tcx>,
+    arg_index: usize,
+    param_ty: ParamTy,
+    mut expr: &Expr<'tcx>,
+    precedence: i8,
+    msrv: Option<RustcVersion>,
+) -> Position {
+    let destruct_trait_def_id = cx.tcx.lang_items().destruct_trait();
+    let sized_trait_def_id = cx.tcx.lang_items().sized_trait();
+
+    let Some(callee_def_id) = fn_def_id(cx, parent) else { return Position::Other(precedence) };
+    let fn_sig = cx.tcx.fn_sig(callee_def_id).skip_binder();
+    let substs_with_expr_ty = cx
+        .typeck_results()
+        .node_substs(if let ExprKind::Call(callee, _) = parent.kind {
+            callee.hir_id
+        } else {
+            parent.hir_id
+        });
+
+    let predicates = cx.tcx.param_env(callee_def_id).caller_bounds();
+    let projection_predicates = predicates
+        .iter()
+        .filter_map(|predicate| {
+            if let PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() {
+                Some(projection_predicate)
+            } else {
+                None
+            }
+        })
+        .collect::<Vec<_>>();
+
+    let mut trait_with_ref_mut_self_method = false;
+
+    // If no traits were found, or only the `Destruct`, `Sized`, or `Any` traits were found, return.
+    if predicates
+        .iter()
+        .filter_map(|predicate| {
+            if let PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder()
+                && trait_predicate.trait_ref.self_ty() == param_ty.to_ty(cx.tcx)
+            {
+                Some(trait_predicate.trait_ref.def_id)
+            } else {
+                None
+            }
+        })
+        .inspect(|trait_def_id| {
+            trait_with_ref_mut_self_method |= has_ref_mut_self_method(cx, *trait_def_id);
+        })
+        .all(|trait_def_id| {
+            Some(trait_def_id) == destruct_trait_def_id
+                || Some(trait_def_id) == sized_trait_def_id
+                || cx.tcx.is_diagnostic_item(sym::Any, trait_def_id)
+        })
+    {
+        return Position::Other(precedence);
+    }
+
+    // `substs_with_referent_ty` can be constructed outside of `check_referent` because the same
+    // elements are modified each time `check_referent` is called.
+    let mut substs_with_referent_ty = substs_with_expr_ty.to_vec();
+
+    let mut check_referent = |referent| {
+        let referent_ty = cx.typeck_results().expr_ty(referent);
+
+        if !is_copy(cx, referent_ty) {
+            return false;
+        }
+
+        // https://github.com/rust-lang/rust-clippy/pull/9136#pullrequestreview-1037379321
+        if trait_with_ref_mut_self_method && !matches!(referent_ty.kind(), ty::Ref(_, _, Mutability::Mut)) {
+            return false;
+        }
+
+        if !replace_types(
+            cx,
+            param_ty,
+            referent_ty,
+            fn_sig,
+            arg_index,
+            &projection_predicates,
+            &mut substs_with_referent_ty,
+        ) {
+            return false;
+        }
+
+        predicates.iter().all(|predicate| {
+            if let PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder()
+                && cx.tcx.is_diagnostic_item(sym::IntoIterator, trait_predicate.trait_ref.def_id)
+                && let ty::Param(param_ty) = trait_predicate.self_ty().kind()
+                && let GenericArgKind::Type(ty) = substs_with_referent_ty[param_ty.index as usize].unpack()
+                && ty.is_array()
+                && !meets_msrv(msrv, msrvs::ARRAY_INTO_ITERATOR)
+            {
+                return false;
+            }
+
+            let predicate = EarlyBinder(predicate).subst(cx.tcx, &substs_with_referent_ty);
+            let obligation = Obligation::new(ObligationCause::dummy(), cx.param_env, predicate);
+            cx.tcx
+                .infer_ctxt()
+                .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
+        })
+    };
+
+    let mut needless_borrow = false;
+    while let ExprKind::AddrOf(_, _, referent) = expr.kind {
+        if !check_referent(referent) {
+            break;
+        }
+        expr = referent;
+        needless_borrow = true;
+    }
+
+    if needless_borrow {
+        Position::ImplArg(expr.hir_id)
+    } else {
+        Position::Other(precedence)
+    }
+}
+
+fn has_ref_mut_self_method(cx: &LateContext<'_>, trait_def_id: DefId) -> bool {
+    cx.tcx
+        .associated_items(trait_def_id)
+        .in_definition_order()
+        .any(|assoc_item| {
+            if assoc_item.fn_has_self_parameter {
+                let self_ty = cx.tcx.fn_sig(assoc_item.def_id).skip_binder().inputs()[0];
+                matches!(self_ty.kind(), ty::Ref(_, _, Mutability::Mut))
+            } else {
+                false
+            }
+        })
+}
+
+// Iteratively replaces `param_ty` with `new_ty` in `substs`, and similarly for each resulting
+// projected type that is a type parameter. Returns `false` if replacing the types would have an
+// effect on the function signature beyond substituting `new_ty` for `param_ty`.
+// See: https://github.com/rust-lang/rust-clippy/pull/9136#discussion_r927212757
+fn replace_types<'tcx>(
+    cx: &LateContext<'tcx>,
+    param_ty: ParamTy,
+    new_ty: Ty<'tcx>,
+    fn_sig: FnSig<'tcx>,
+    arg_index: usize,
+    projection_predicates: &[ProjectionPredicate<'tcx>],
+    substs: &mut [ty::GenericArg<'tcx>],
+) -> bool {
+    let mut replaced = BitSet::new_empty(substs.len());
+
+    let mut deque = VecDeque::with_capacity(substs.len());
+    deque.push_back((param_ty, new_ty));
+
+    while let Some((param_ty, new_ty)) = deque.pop_front() {
+        // If `replaced.is_empty()`, then `param_ty` and `new_ty` are those initially passed in.
+        if !fn_sig
+            .inputs_and_output
+            .iter()
+            .enumerate()
+            .all(|(i, ty)| (replaced.is_empty() && i == arg_index) || !ty.contains(param_ty.to_ty(cx.tcx)))
+        {
+            return false;
+        }
+
+        substs[param_ty.index as usize] = ty::GenericArg::from(new_ty);
+
+        // The `replaced.insert(...)` check provides some protection against infinite loops.
+        if replaced.insert(param_ty.index) {
+            for projection_predicate in projection_predicates {
+                if projection_predicate.projection_ty.self_ty() == param_ty.to_ty(cx.tcx)
+                    && let Some(term_ty) = projection_predicate.term.ty()
+                    && let ty::Param(term_param_ty) = term_ty.kind()
+                {
+                    let item_def_id = projection_predicate.projection_ty.item_def_id;
+                    let assoc_item = cx.tcx.associated_item(item_def_id);
+                    let projection = cx.tcx
+                        .mk_projection(assoc_item.def_id, cx.tcx.mk_substs_trait(new_ty, &[]));
+
+                    if let Ok(projected_ty) = cx.tcx.try_normalize_erasing_regions(cx.param_env, projection)
+                        && substs[term_param_ty.index as usize] != ty::GenericArg::from(projected_ty)
+                    {
+                        deque.push_back((*term_param_ty, projected_ty));
+                    }
+                }
+            }
+        }
+    }
+
+    true
+}
+
 struct TyPosition<'tcx> {
     position: Position,
     ty: Option<Ty<'tcx>>,
@@ -1086,7 +1328,8 @@ fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data
         },
         State::DerefedBorrow(state) => {
             let mut app = Applicability::MachineApplicable;
-            let (snip, snip_is_macro) = snippet_with_context(cx, expr.span, data.span.ctxt(), "..", &mut app);
+            let snip_expr = state.snip_expr.map_or(expr, |hir_id| cx.tcx.hir().expect_expr(hir_id));
+            let (snip, snip_is_macro) = snippet_with_context(cx, snip_expr.span, data.span.ctxt(), "..", &mut app);
             span_lint_hir_and_then(cx, NEEDLESS_BORROW, data.hir_id, data.span, state.msg, |diag| {
                 let calls_field = matches!(expr.kind, ExprKind::Field(..)) && matches!(data.position, Position::Callee);
                 let sugg = if !snip_is_macro
diff --git a/src/tools/clippy/clippy_lints/src/derivable_impls.rs b/src/tools/clippy/clippy_lints/src/derivable_impls.rs
index 4d7f4076d7b5..06ae5abeaeb9 100644
--- a/src/tools/clippy/clippy_lints/src/derivable_impls.rs
+++ b/src/tools/clippy/clippy_lints/src/derivable_impls.rs
@@ -1,5 +1,6 @@
-use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::{is_default_equivalent, peel_blocks};
+use rustc_errors::Applicability;
 use rustc_hir::{
     def::{DefKind, Res},
     Body, Expr, ExprKind, GenericArg, Impl, ImplItemKind, Item, ItemKind, Node, PathSegment, QPath, TyKind,
@@ -40,7 +41,7 @@ declare_clippy_lint! {
     ///
     /// ### Known problems
     /// Derive macros [sometimes use incorrect bounds](https://github.com/rust-lang/rust/issues/26925)
-    /// in generic types and the user defined `impl` maybe is more generalized or
+    /// in generic types and the user defined `impl` may be more generalized or
     /// specialized than what derive will produce. This lint can't detect the manual `impl`
     /// has exactly equal bounds, and therefore this lint is disabled for types with
     /// generic parameters.
@@ -100,15 +101,28 @@ impl<'tcx> LateLintPass<'tcx> for DerivableImpls {
                     ExprKind::Struct(_, fields, _) => fields.iter().all(|ef| is_default_equivalent(cx, ef.expr)),
                     _ => false,
                 };
+
                 if should_emit {
-                    let path_string = cx.tcx.def_path_str(adt_def.did());
-                    span_lint_and_help(
+                    let struct_span = cx.tcx.def_span(adt_def.did());
+                    span_lint_and_then(
                         cx,
                         DERIVABLE_IMPLS,
                         item.span,
                         "this `impl` can be derived",
-                        None,
-                        &format!("try annotating `{}` with `#[derive(Default)]`", path_string),
+                        |diag| {
+                            diag.span_suggestion_hidden(
+                                item.span,
+                                "remove the manual implementation...",
+                                String::new(),
+                                Applicability::MachineApplicable
+                            );
+                            diag.span_suggestion(
+                                struct_span.shrink_to_lo(),
+                                "...and instead derive it",
+                                "#[derive(Default)]\n".to_string(),
+                                Applicability::MachineApplicable
+                            );
+                        }
                     );
                 }
             }
diff --git a/src/tools/clippy/clippy_lints/src/derive.rs b/src/tools/clippy/clippy_lints/src/derive.rs
index a982990e4186..751ca24d5f59 100644
--- a/src/tools/clippy/clippy_lints/src/derive.rs
+++ b/src/tools/clippy/clippy_lints/src/derive.rs
@@ -15,7 +15,7 @@ use rustc_middle::hir::nested_filter;
 use rustc_middle::traits::Reveal;
 use rustc_middle::ty::{
     self, Binder, BoundConstness, GenericParamDefKind, ImplPolarity, ParamEnv, PredicateKind, TraitPredicate, TraitRef,
-    Ty, TyCtxt, Visibility,
+    Ty, TyCtxt,
 };
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
@@ -425,7 +425,7 @@ struct UnsafeVisitor<'a, 'tcx> {
 impl<'tcx> Visitor<'tcx> for UnsafeVisitor<'_, 'tcx> {
     type NestedFilter = nested_filter::All;
 
-    fn visit_fn(&mut self, kind: FnKind<'tcx>, decl: &'tcx FnDecl<'_>, body_id: BodyId, span: Span, id: HirId) {
+    fn visit_fn(&mut self, kind: FnKind<'tcx>, decl: &'tcx FnDecl<'_>, body_id: BodyId, _: Span, id: HirId) {
         if self.has_unsafe {
             return;
         }
@@ -438,7 +438,7 @@ impl<'tcx> Visitor<'tcx> for UnsafeVisitor<'_, 'tcx> {
             }
         }
 
-        walk_fn(self, kind, decl, body_id, span, id);
+        walk_fn(self, kind, decl, body_id, id);
     }
 
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
@@ -464,7 +464,7 @@ impl<'tcx> Visitor<'tcx> for UnsafeVisitor<'_, 'tcx> {
 fn check_partial_eq_without_eq<'tcx>(cx: &LateContext<'tcx>, span: Span, trait_ref: &hir::TraitRef<'_>, ty: Ty<'tcx>) {
     if_chain! {
         if let ty::Adt(adt, substs) = ty.kind();
-        if cx.tcx.visibility(adt.did()) == Visibility::Public;
+        if cx.tcx.visibility(adt.did()).is_public();
         if let Some(eq_trait_def_id) = cx.tcx.get_diagnostic_item(sym::Eq);
         if let Some(def_id) = trait_ref.trait_def_id();
         if cx.tcx.is_diagnostic_item(sym::PartialEq, def_id);
@@ -516,7 +516,10 @@ fn param_env_for_derived_eq(tcx: TyCtxt<'_>, did: DefId, eq_trait_id: DefId) ->
         tcx.mk_predicates(ty_predicates.iter().map(|&(p, _)| p).chain(
             params.iter().filter(|&&(_, needs_eq)| needs_eq).map(|&(param, _)| {
                 tcx.mk_predicate(Binder::dummy(PredicateKind::Trait(TraitPredicate {
-                    trait_ref: TraitRef::new(eq_trait_id, tcx.mk_substs([tcx.mk_param_from_def(param)].into_iter())),
+                    trait_ref: TraitRef::new(
+                        eq_trait_id,
+                        tcx.mk_substs(std::iter::once(tcx.mk_param_from_def(param))),
+                    ),
                     constness: BoundConstness::NotConst,
                     polarity: ImplPolarity::Positive,
                 })))
diff --git a/src/tools/clippy/clippy_lints/src/disallowed_types.rs b/src/tools/clippy/clippy_lints/src/disallowed_types.rs
index 14f89edce615..28dbfbab2e19 100644
--- a/src/tools/clippy/clippy_lints/src/disallowed_types.rs
+++ b/src/tools/clippy/clippy_lints/src/disallowed_types.rs
@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_then;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::{
-    def::Res, def_id::DefId, Item, ItemKind, PolyTraitRef, PrimTy, TraitBoundModifier, Ty, TyKind, UseKind,
+    def::Res, def_id::DefId, Item, ItemKind, PolyTraitRef, PrimTy, Ty, TyKind, UseKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
@@ -120,7 +120,7 @@ impl<'tcx> LateLintPass<'tcx> for DisallowedTypes {
         }
     }
 
-    fn check_poly_trait_ref(&mut self, cx: &LateContext<'tcx>, poly: &'tcx PolyTraitRef<'tcx>, _: TraitBoundModifier) {
+    fn check_poly_trait_ref(&mut self, cx: &LateContext<'tcx>, poly: &'tcx PolyTraitRef<'tcx>) {
         self.check_res_emit(cx, &poly.trait_ref.path.res, poly.trait_ref.path.span);
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/doc.rs b/src/tools/clippy/clippy_lints/src/doc.rs
index da111e7378ea..f48ba526d51e 100644
--- a/src/tools/clippy/clippy_lints/src/doc.rs
+++ b/src/tools/clippy/clippy_lints/src/doc.rs
@@ -233,11 +233,11 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
                     let body = cx.tcx.hir().body(body_id);
                     let mut fpu = FindPanicUnwrap {
                         cx,
-                        typeck_results: cx.tcx.typeck(item.def_id),
+                        typeck_results: cx.tcx.typeck(item.def_id.def_id),
                         panic_span: None,
                     };
-                    fpu.visit_expr(&body.value);
-                    lint_for_missing_headers(cx, item.def_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
+                    fpu.visit_expr(body.value);
+                    lint_for_missing_headers(cx, item.def_id.def_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
                 }
             },
             hir::ItemKind::Impl(impl_) => {
@@ -268,7 +268,7 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
         let headers = check_attrs(cx, &self.valid_idents, attrs);
         if let hir::TraitItemKind::Fn(ref sig, ..) = item.kind {
             if !in_external_macro(cx.tcx.sess, item.span) {
-                lint_for_missing_headers(cx, item.def_id, item.span, sig, headers, None, None);
+                lint_for_missing_headers(cx, item.def_id.def_id, item.span, sig, headers, None, None);
             }
         }
     }
@@ -283,11 +283,11 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
             let body = cx.tcx.hir().body(body_id);
             let mut fpu = FindPanicUnwrap {
                 cx,
-                typeck_results: cx.tcx.typeck(item.def_id),
+                typeck_results: cx.tcx.typeck(item.def_id.def_id),
                 panic_span: None,
             };
-            fpu.visit_expr(&body.value);
-            lint_for_missing_headers(cx, item.def_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
+            fpu.visit_expr(body.value);
+            lint_for_missing_headers(cx, item.def_id.def_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
         }
     }
 }
@@ -348,7 +348,7 @@ fn lint_for_missing_headers<'tcx>(
                 if let Some(future) = cx.tcx.lang_items().future_trait();
                 let typeck = cx.tcx.typeck_body(body_id);
                 let body = cx.tcx.hir().body(body_id);
-                let ret_ty = typeck.expr_ty(&body.value);
+                let ret_ty = typeck.expr_ty(body.value);
                 if implements_trait(cx, ret_ty, future, &[]);
                 if let ty::Opaque(_, subs) = ret_ty.kind();
                 if let Some(gen) = subs.types().next();
@@ -828,7 +828,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindPanicUnwrap<'a, 'tcx> {
 
         // check for `unwrap`
         if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
-            let receiver_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
+            let receiver_ty = self.typeck_results.expr_ty(arglists[0].0).peel_refs();
             if is_type_diagnostic_item(self.cx, receiver_ty, sym::Option)
                 || is_type_diagnostic_item(self.cx, receiver_ty, sym::Result)
             {
diff --git a/src/tools/clippy/clippy_lints/src/doc_link_with_quotes.rs b/src/tools/clippy/clippy_lints/src/doc_link_with_quotes.rs
index cb07f57e8700..0ff1d2755daf 100644
--- a/src/tools/clippy/clippy_lints/src/doc_link_with_quotes.rs
+++ b/src/tools/clippy/clippy_lints/src/doc_link_with_quotes.rs
@@ -21,7 +21,7 @@ declare_clippy_lint! {
     /// /// See also: [`foo`]
     /// fn bar() {}
     /// ```
-    #[clippy::version = "1.60.0"]
+    #[clippy::version = "1.63.0"]
     pub DOC_LINK_WITH_QUOTES,
     pedantic,
     "possible typo for an intra-doc link"
diff --git a/src/tools/clippy/clippy_lints/src/duplicate_mod.rs b/src/tools/clippy/clippy_lints/src/duplicate_mod.rs
index e1eb3b6324c7..7ff7068f0b05 100644
--- a/src/tools/clippy/clippy_lints/src/duplicate_mod.rs
+++ b/src/tools/clippy/clippy_lints/src/duplicate_mod.rs
@@ -39,7 +39,7 @@ declare_clippy_lint! {
     /// // a.rs
     /// use crate::b;
     /// ```
-    #[clippy::version = "1.62.0"]
+    #[clippy::version = "1.63.0"]
     pub DUPLICATE_MOD,
     suspicious,
     "file loaded as module multiple times"
diff --git a/src/tools/clippy/clippy_lints/src/entry.rs b/src/tools/clippy/clippy_lints/src/entry.rs
index 4e3ae4c96141..e70df3f53c75 100644
--- a/src/tools/clippy/clippy_lints/src/entry.rs
+++ b/src/tools/clippy/clippy_lints/src/entry.rs
@@ -245,8 +245,8 @@ fn try_parse_contains<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Optio
     match expr.kind {
         ExprKind::MethodCall(
             _,
+            map,
             [
-                map,
                 Expr {
                     kind: ExprKind::AddrOf(_, _, key),
                     span: key_span,
@@ -280,7 +280,7 @@ struct InsertExpr<'tcx> {
     value: &'tcx Expr<'tcx>,
 }
 fn try_parse_insert<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<InsertExpr<'tcx>> {
-    if let ExprKind::MethodCall(_, [map, key, value], _) = expr.kind {
+    if let ExprKind::MethodCall(_, map, [key, value], _) = expr.kind {
         let id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?;
         if match_def_path(cx, id, &paths::BTREEMAP_INSERT) || match_def_path(cx, id, &paths::HASHMAP_INSERT) {
             Some(InsertExpr { map, key, value })
diff --git a/src/tools/clippy/clippy_lints/src/enum_variants.rs b/src/tools/clippy/clippy_lints/src/enum_variants.rs
index cd36f9fcd729..c39a909b3ccb 100644
--- a/src/tools/clippy/clippy_lints/src/enum_variants.rs
+++ b/src/tools/clippy/clippy_lints/src/enum_variants.rs
@@ -297,7 +297,7 @@ impl LateLintPass<'_> for EnumVariantNames {
             }
         }
         if let ItemKind::Enum(ref def, _) = item.kind {
-            if !(self.avoid_breaking_exported_api && cx.access_levels.is_exported(item.def_id)) {
+            if !(self.avoid_breaking_exported_api && cx.access_levels.is_exported(item.def_id.def_id)) {
                 check_variant(cx, self.threshold, def, item_name, item.span);
             }
         }
diff --git a/src/tools/clippy/clippy_lints/src/equatable_if_let.rs b/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
index fdfb821ac789..bce49165e5b1 100644
--- a/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
+++ b/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
@@ -51,7 +51,9 @@ fn unary_pattern(pat: &Pat<'_>) -> bool {
             false
         },
         PatKind::Struct(_, a, etc) => !etc && a.iter().all(|x| unary_pattern(x.pat)),
-        PatKind::Tuple(a, etc) | PatKind::TupleStruct(_, a, etc) => !etc.is_some() && array_rec(a),
+        PatKind::Tuple(a, etc) | PatKind::TupleStruct(_, a, etc) => {
+            !etc.as_opt_usize().is_some() && array_rec(a)
+        }
         PatKind::Ref(x, _) | PatKind::Box(x) => unary_pattern(x),
         PatKind::Path(_) | PatKind::Lit(_) => true,
     }
diff --git a/src/tools/clippy/clippy_lints/src/escape.rs b/src/tools/clippy/clippy_lints/src/escape.rs
index 1ac7bfba06ba..a6ddb26e2dee 100644
--- a/src/tools/clippy/clippy_lints/src/escape.rs
+++ b/src/tools/clippy/clippy_lints/src/escape.rs
@@ -1,5 +1,4 @@
 use clippy_utils::diagnostics::span_lint_hir;
-use clippy_utils::ty::contains_ty;
 use rustc_hir::intravisit;
 use rustc_hir::{self, AssocItemKind, Body, FnDecl, HirId, HirIdSet, Impl, ItemKind, Node, Pat, PatKind};
 use rustc_infer::infer::TyCtxtInferExt;
@@ -30,18 +29,12 @@ declare_clippy_lint! {
     ///
     /// ### Example
     /// ```rust
-    /// # fn foo(bar: usize) {}
-    /// let x = Box::new(1);
-    /// foo(*x);
-    /// println!("{}", *x);
+    /// fn foo(x: Box<u32>) {}
     /// ```
     ///
     /// Use instead:
     /// ```rust
-    /// # fn foo(bar: usize) {}
-    /// let x = 1;
-    /// foo(x);
-    /// println!("{}", x);
+    /// fn foo(x: u32) {}
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub BOXED_LOCAL,
@@ -78,7 +71,7 @@ impl<'tcx> LateLintPass<'tcx> for BoxedLocal {
             }
         }
 
-        let parent_id = cx.tcx.hir().get_parent_item(hir_id);
+        let parent_id = cx.tcx.hir().get_parent_item(hir_id).def_id;
         let parent_node = cx.tcx.hir().find_by_def_id(parent_id);
 
         let mut trait_self_ty = None;
@@ -172,7 +165,7 @@ impl<'a, 'tcx> Delegate<'tcx> for EscapeDelegate<'a, 'tcx> {
                 // skip if there is a `self` parameter binding to a type
                 // that contains `Self` (i.e.: `self: Box<Self>`), see #4804
                 if let Some(trait_self_ty) = self.trait_self_ty {
-                    if map.name(cmt.hir_id) == kw::SelfLower && contains_ty(cmt.place.ty(), trait_self_ty) {
+                    if map.name(cmt.hir_id) == kw::SelfLower && cmt.place.ty().contains(trait_self_ty) {
                         return;
                     }
                 }
diff --git a/src/tools/clippy/clippy_lints/src/eta_reduction.rs b/src/tools/clippy/clippy_lints/src/eta_reduction.rs
index 4f9ff97f1fd1..598f8c31859e 100644
--- a/src/tools/clippy/clippy_lints/src/eta_reduction.rs
+++ b/src/tools/clippy/clippy_lints/src/eta_reduction.rs
@@ -11,7 +11,6 @@ use rustc_hir::{Closure, Expr, ExprKind, Param, PatKind, Unsafety};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
 use rustc_middle::ty::binding::BindingMode;
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, ClosureKind, Ty, TypeVisitable};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
@@ -83,7 +82,7 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
         };
         if body.value.span.from_expansion() {
             if body.params.is_empty() {
-                if let Some(VecArgs::Vec(&[])) = higher::VecArgs::hir(cx, &body.value) {
+                if let Some(VecArgs::Vec(&[])) = higher::VecArgs::hir(cx, body.value) {
                     // replace `|| vec![]` with `Vec::new`
                     span_lint_and_sugg(
                         cx,
@@ -103,10 +102,10 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
         let closure_ty = cx.typeck_results().expr_ty(expr);
 
         if_chain!(
-            if !is_adjusted(cx, &body.value);
+            if !is_adjusted(cx, body.value);
             if let ExprKind::Call(callee, args) = body.value.kind;
             if let ExprKind::Path(_) = callee.kind;
-            if check_inputs(cx, body.params, args);
+            if check_inputs(cx, body.params, None, args);
             let callee_ty = cx.typeck_results().expr_ty_adjusted(callee);
             let call_ty = cx.typeck_results().type_dependent_def_id(body.value.hir_id)
                 .map_or(callee_ty, |id| cx.tcx.type_of(id));
@@ -145,9 +144,9 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
         );
 
         if_chain!(
-            if !is_adjusted(cx, &body.value);
-            if let ExprKind::MethodCall(path, args, _) = body.value.kind;
-            if check_inputs(cx, body.params, args);
+            if !is_adjusted(cx, body.value);
+            if let ExprKind::MethodCall(path, receiver, args, _) = body.value.kind;
+            if check_inputs(cx, body.params, Some(receiver), args);
             let method_def_id = cx.typeck_results().type_dependent_def_id(body.value.hir_id).unwrap();
             let substs = cx.typeck_results().node_substs(body.value.hir_id);
             let call_ty = cx.tcx.bound_type_of(method_def_id).subst(cx.tcx, substs);
@@ -167,12 +166,17 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
     }
 }
 
-fn check_inputs(cx: &LateContext<'_>, params: &[Param<'_>], call_args: &[Expr<'_>]) -> bool {
-    if params.len() != call_args.len() {
+fn check_inputs(
+    cx: &LateContext<'_>,
+    params: &[Param<'_>],
+    receiver: Option<&Expr<'_>>,
+    call_args: &[Expr<'_>],
+) -> bool {
+    if receiver.map_or(params.len() != call_args.len(), |_| params.len() != call_args.len() + 1) {
         return false;
     }
     let binding_modes = cx.typeck_results().pat_binding_modes();
-    std::iter::zip(params, call_args).all(|(param, arg)| {
+    let check_inputs = |param: &Param<'_>, arg| {
         match param.pat.kind {
             PatKind::Binding(_, id, ..) if path_to_local_id(arg, id) => {},
             _ => return false,
@@ -200,7 +204,8 @@ fn check_inputs(cx: &LateContext<'_>, params: &[Param<'_>], call_args: &[Expr<'_
             },
             _ => false,
         }
-    })
+    };
+    std::iter::zip(params, receiver.into_iter().chain(call_args.iter())).all(|(param, arg)| check_inputs(param, arg))
 }
 
 fn check_sig<'tcx>(cx: &LateContext<'tcx>, closure_ty: Ty<'tcx>, call_ty: Ty<'tcx>) -> bool {
diff --git a/src/tools/clippy/clippy_lints/src/exhaustive_items.rs b/src/tools/clippy/clippy_lints/src/exhaustive_items.rs
index 173d41b4b050..f3d9ebc5f12d 100644
--- a/src/tools/clippy/clippy_lints/src/exhaustive_items.rs
+++ b/src/tools/clippy/clippy_lints/src/exhaustive_items.rs
@@ -73,7 +73,7 @@ impl LateLintPass<'_> for ExhaustiveItems {
     fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
         if_chain! {
             if let ItemKind::Enum(..) | ItemKind::Struct(..) = item.kind;
-            if cx.access_levels.is_exported(item.def_id);
+            if cx.access_levels.is_exported(item.def_id.def_id);
             let attrs = cx.tcx.hir().attrs(item.hir_id());
             if !attrs.iter().any(|a| a.has_name(sym::non_exhaustive));
             then {
diff --git a/src/tools/clippy/clippy_lints/src/exit.rs b/src/tools/clippy/clippy_lints/src/exit.rs
index cbf52d19334c..407dd1b39575 100644
--- a/src/tools/clippy/clippy_lints/src/exit.rs
+++ b/src/tools/clippy/clippy_lints/src/exit.rs
@@ -33,7 +33,7 @@ impl<'tcx> LateLintPass<'tcx> for Exit {
             if let ExprKind::Path(ref path) = path_expr.kind;
             if let Some(def_id) = cx.qpath_res(path, path_expr.hir_id).opt_def_id();
             if match_def_path(cx, def_id, &paths::EXIT);
-            let parent = cx.tcx.hir().get_parent_item(e.hir_id);
+            let parent = cx.tcx.hir().get_parent_item(e.hir_id).def_id;
             if let Some(Node::Item(Item{kind: ItemKind::Fn(..), ..})) = cx.tcx.hir().find_by_def_id(parent);
             // If the next item up is a function we check if it is an entry point
             // and only then emit a linter warning
diff --git a/src/tools/clippy/clippy_lints/src/explicit_write.rs b/src/tools/clippy/clippy_lints/src/explicit_write.rs
index 5bf4313b41a4..b9ed4af02190 100644
--- a/src/tools/clippy/clippy_lints/src/explicit_write.rs
+++ b/src/tools/clippy/clippy_lints/src/explicit_write.rs
@@ -45,10 +45,10 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if_chain! {
             // match call to unwrap
-            if let ExprKind::MethodCall(unwrap_fun, [write_call], _) = expr.kind;
+            if let ExprKind::MethodCall(unwrap_fun, write_call, [], _) = expr.kind;
             if unwrap_fun.ident.name == sym::unwrap;
             // match call to write_fmt
-            if let ExprKind::MethodCall(write_fun, [write_recv, write_arg], _) = look_in_block(cx, &write_call.kind);
+            if let ExprKind::MethodCall(write_fun, write_recv, [write_arg], _) = look_in_block(cx, &write_call.kind);
             if write_fun.ident.name == sym!(write_fmt);
             // match calls to std::io::stdout() / std::io::stderr ()
             if let Some(dest_name) = if match_function_call(cx, write_recv, &paths::STDOUT).is_some() {
@@ -128,7 +128,7 @@ fn look_in_block<'tcx, 'hir>(cx: &LateContext<'tcx>, kind: &'tcx ExprKind<'hir>)
         if let Some(Node::Pat(res_pat)) = cx.tcx.hir().find(expr_res);
 
         // Find id of the local we found in the block
-        if let PatKind::Binding(BindingAnnotation::Unannotated, local_hir_id, _ident, None) = local.pat.kind;
+        if let PatKind::Binding(BindingAnnotation::NONE, local_hir_id, _ident, None) = local.pat.kind;
 
         // If those two are the same hir id
         if res_pat.hir_id == local_hir_id;
diff --git a/src/tools/clippy/clippy_lints/src/fallible_impl_from.rs b/src/tools/clippy/clippy_lints/src/fallible_impl_from.rs
index b88e53aeca69..ef24a5d06ad0 100644
--- a/src/tools/clippy/clippy_lints/src/fallible_impl_from.rs
+++ b/src/tools/clippy/clippy_lints/src/fallible_impl_from.rs
@@ -84,7 +84,7 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_items: &[h
 
             // check for `unwrap`
             if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
-                let receiver_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
+                let receiver_ty = self.typeck_results.expr_ty(arglists[0].0).peel_refs();
                 if is_type_diagnostic_item(self.lcx, receiver_ty, sym::Option)
                     || is_type_diagnostic_item(self.lcx, receiver_ty, sym::Result)
                 {
@@ -107,10 +107,10 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_items: &[h
                 let body = cx.tcx.hir().body(body_id);
                 let mut fpu = FindPanicUnwrap {
                     lcx: cx,
-                    typeck_results: cx.tcx.typeck(impl_item.id.def_id),
+                    typeck_results: cx.tcx.typeck(impl_item.id.def_id.def_id),
                     result: Vec::new(),
                 };
-                fpu.visit_expr(&body.value);
+                fpu.visit_expr(body.value);
 
                 // if we've found one, lint
                 if !fpu.result.is_empty() {
diff --git a/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs b/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs
index df9b41d2c98b..ba53a9678801 100644
--- a/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs
+++ b/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs
@@ -164,15 +164,15 @@ fn prepare_receiver_sugg<'a>(cx: &LateContext<'_>, mut expr: &'a Expr<'a>) -> Su
     suggestion.maybe_par()
 }
 
-fn check_log_base(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
-    if let Some(method) = get_specialized_log_method(cx, &args[1]) {
+fn check_log_base(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
+    if let Some(method) = get_specialized_log_method(cx, &args[0]) {
         span_lint_and_sugg(
             cx,
             SUBOPTIMAL_FLOPS,
             expr.span,
             "logarithm for bases 2, 10 and e can be computed more accurately",
             "consider using",
-            format!("{}.{}()", Sugg::hir(cx, &args[0], ".."), method),
+            format!("{}.{}()", Sugg::hir(cx, receiver, "..").maybe_par(), method),
             Applicability::MachineApplicable,
         );
     }
@@ -180,14 +180,14 @@ fn check_log_base(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
 
 // TODO: Lint expressions of the form `(x + y).ln()` where y > 1 and
 // suggest usage of `(x + (y - 1)).ln_1p()` instead
-fn check_ln1p(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+fn check_ln1p(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>) {
     if let ExprKind::Binary(
         Spanned {
             node: BinOpKind::Add, ..
         },
         lhs,
         rhs,
-    ) = &args[0].kind
+    ) = receiver.kind
     {
         let recv = match (
             constant(cx, cx.typeck_results(), lhs),
@@ -235,41 +235,41 @@ fn get_integer_from_float_constant(value: &Constant) -> Option<i32> {
     }
 }
 
-fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
+fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
     // Check receiver
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
-        let method = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
-            "exp"
+    if let Some((value, _)) = constant(cx, cx.typeck_results(), receiver) {
+        if let Some(method) = if F32(f32_consts::E) == value || F64(f64_consts::E) == value {
+            Some("exp")
         } else if F32(2.0) == value || F64(2.0) == value {
-            "exp2"
+            Some("exp2")
         } else {
-            return;
-        };
-
-        span_lint_and_sugg(
-            cx,
-            SUBOPTIMAL_FLOPS,
-            expr.span,
-            "exponent for bases 2 and e can be computed more accurately",
-            "consider using",
-            format!("{}.{}()", prepare_receiver_sugg(cx, &args[1]), method),
-            Applicability::MachineApplicable,
-        );
+            None
+        } {
+            span_lint_and_sugg(
+                cx,
+                SUBOPTIMAL_FLOPS,
+                expr.span,
+                "exponent for bases 2 and e can be computed more accurately",
+                "consider using",
+                format!("{}.{}()", prepare_receiver_sugg(cx, &args[0]), method),
+                Applicability::MachineApplicable,
+            );
+        }
     }
 
     // Check argument
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[1]) {
+    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
         let (lint, help, suggestion) = if F32(1.0 / 2.0) == value || F64(1.0 / 2.0) == value {
             (
                 SUBOPTIMAL_FLOPS,
                 "square-root of a number can be computed more efficiently and accurately",
-                format!("{}.sqrt()", Sugg::hir(cx, &args[0], "..")),
+                format!("{}.sqrt()", Sugg::hir(cx, receiver, "..").maybe_par()),
             )
         } else if F32(1.0 / 3.0) == value || F64(1.0 / 3.0) == value {
             (
                 IMPRECISE_FLOPS,
                 "cube-root of a number can be computed more accurately",
-                format!("{}.cbrt()", Sugg::hir(cx, &args[0], "..")),
+                format!("{}.cbrt()", Sugg::hir(cx, receiver, "..").maybe_par()),
             )
         } else if let Some(exponent) = get_integer_from_float_constant(&value) {
             (
@@ -277,7 +277,7 @@ fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
                 "exponentiation with integer powers can be computed more efficiently",
                 format!(
                     "{}.powi({})",
-                    Sugg::hir(cx, &args[0], ".."),
+                    Sugg::hir(cx, receiver, "..").maybe_par(),
                     numeric_literal::format(&exponent.to_string(), None, false)
                 ),
             )
@@ -297,13 +297,14 @@ fn check_powf(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
     }
 }
 
-fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
-    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[1]) {
+fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args: &[Expr<'_>]) {
+    if let Some((value, _)) = constant(cx, cx.typeck_results(), &args[0]) {
         if value == Int(2) {
             if let Some(parent) = get_parent_expr(cx, expr) {
                 if let Some(grandparent) = get_parent_expr(cx, parent) {
-                    if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, args, _) = grandparent.kind {
-                        if method_name.as_str() == "sqrt" && detect_hypot(cx, args).is_some() {
+                    if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, receiver, ..) = grandparent.kind
+                    {
+                        if method_name.as_str() == "sqrt" && detect_hypot(cx, receiver).is_some() {
                             return;
                         }
                     }
@@ -327,8 +328,8 @@ fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
                         "consider using",
                         format!(
                             "{}.mul_add({}, {})",
-                            Sugg::hir(cx, &args[0], ".."),
-                            Sugg::hir(cx, &args[0], ".."),
+                            Sugg::hir(cx, receiver, "..").maybe_par(),
+                            Sugg::hir(cx, receiver, ".."),
                             Sugg::hir(cx, other_addend, ".."),
                         ),
                         Applicability::MachineApplicable,
@@ -339,14 +340,14 @@ fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
     }
 }
 
-fn detect_hypot(cx: &LateContext<'_>, args: &[Expr<'_>]) -> Option<String> {
+fn detect_hypot(cx: &LateContext<'_>, receiver: &Expr<'_>) -> Option<String> {
     if let ExprKind::Binary(
         Spanned {
             node: BinOpKind::Add, ..
         },
         add_lhs,
         add_rhs,
-    ) = args[0].kind
+    ) = receiver.kind
     {
         // check if expression of the form x * x + y * y
         if_chain! {
@@ -363,12 +364,12 @@ fn detect_hypot(cx: &LateContext<'_>, args: &[Expr<'_>]) -> Option<String> {
         if_chain! {
             if let ExprKind::MethodCall(
                 PathSegment { ident: lmethod_name, .. },
-                [largs_0, largs_1, ..],
+                largs_0, [largs_1, ..],
                 _
             ) = &add_lhs.kind;
             if let ExprKind::MethodCall(
                 PathSegment { ident: rmethod_name, .. },
-                [rargs_0, rargs_1, ..],
+                rargs_0, [rargs_1, ..],
                 _
             ) = &add_rhs.kind;
             if lmethod_name.as_str() == "powi" && rmethod_name.as_str() == "powi";
@@ -384,8 +385,8 @@ fn detect_hypot(cx: &LateContext<'_>, args: &[Expr<'_>]) -> Option<String> {
     None
 }
 
-fn check_hypot(cx: &LateContext<'_>, expr: &Expr<'_>, args: &[Expr<'_>]) {
-    if let Some(message) = detect_hypot(cx, args) {
+fn check_hypot(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>) {
+    if let Some(message) = detect_hypot(cx, receiver) {
         span_lint_and_sugg(
             cx,
             IMPRECISE_FLOPS,
@@ -406,7 +407,7 @@ fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) {
         if cx.typeck_results().expr_ty(lhs).is_floating_point();
         if let Some((value, _)) = constant(cx, cx.typeck_results(), rhs);
         if F32(1.0) == value || F64(1.0) == value;
-        if let ExprKind::MethodCall(path, [self_arg, ..], _) = &lhs.kind;
+        if let ExprKind::MethodCall(path, self_arg, ..) = &lhs.kind;
         if cx.typeck_results().expr_ty(self_arg).is_floating_point();
         if path.ident.name.as_str() == "exp";
         then {
@@ -418,7 +419,7 @@ fn check_expm1(cx: &LateContext<'_>, expr: &Expr<'_>) {
                 "consider using",
                 format!(
                     "{}.exp_m1()",
-                    Sugg::hir(cx, self_arg, "..")
+                    Sugg::hir(cx, self_arg, "..").maybe_par()
                 ),
                 Applicability::MachineApplicable,
             );
@@ -450,8 +451,8 @@ fn check_mul_add(cx: &LateContext<'_>, expr: &Expr<'_>) {
     ) = &expr.kind
     {
         if let Some(parent) = get_parent_expr(cx, expr) {
-            if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, args, _) = parent.kind {
-                if method_name.as_str() == "sqrt" && detect_hypot(cx, args).is_some() {
+            if let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, receiver, ..) = parent.kind {
+                if method_name.as_str() == "sqrt" && detect_hypot(cx, receiver).is_some() {
                     return;
                 }
             }
@@ -550,11 +551,11 @@ fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
         then {
             let positive_abs_sugg = (
                 "manual implementation of `abs` method",
-                format!("{}.abs()", Sugg::hir(cx, body, "..")),
+                format!("{}.abs()", Sugg::hir(cx, body, "..").maybe_par()),
             );
             let negative_abs_sugg = (
                 "manual implementation of negation of `abs` method",
-                format!("-{}.abs()", Sugg::hir(cx, body, "..")),
+                format!("-{}.abs()", Sugg::hir(cx, body, "..").maybe_par()),
             );
             let sugg = if is_testing_positive(cx, cond, body) {
                 if if_expr_positive {
@@ -586,14 +587,14 @@ fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
 
 fn are_same_base_logs(cx: &LateContext<'_>, expr_a: &Expr<'_>, expr_b: &Expr<'_>) -> bool {
     if_chain! {
-        if let ExprKind::MethodCall(PathSegment { ident: method_name_a, .. }, args_a, _) = expr_a.kind;
-        if let ExprKind::MethodCall(PathSegment { ident: method_name_b, .. }, args_b, _) = expr_b.kind;
+        if let ExprKind::MethodCall(PathSegment { ident: method_name_a, .. }, _, args_a, _) = expr_a.kind;
+        if let ExprKind::MethodCall(PathSegment { ident: method_name_b, .. }, _, args_b, _) = expr_b.kind;
         then {
             return method_name_a.as_str() == method_name_b.as_str() &&
                 args_a.len() == args_b.len() &&
                 (
                     ["ln", "log2", "log10"].contains(&method_name_a.as_str()) ||
-                    method_name_a.as_str() == "log" && args_a.len() == 2 && eq_expr_value(cx, &args_a[1], &args_b[1])
+                    method_name_a.as_str() == "log" && args_a.len() == 1 && eq_expr_value(cx, &args_a[0], &args_b[0])
                 );
         }
     }
@@ -612,8 +613,8 @@ fn check_log_division(cx: &LateContext<'_>, expr: &Expr<'_>) {
             rhs,
         ) = &expr.kind;
         if are_same_base_logs(cx, lhs, rhs);
-        if let ExprKind::MethodCall(_, [largs_self, ..], _) = &lhs.kind;
-        if let ExprKind::MethodCall(_, [rargs_self, ..], _) = &rhs.kind;
+        if let ExprKind::MethodCall(_, largs_self, ..) = &lhs.kind;
+        if let ExprKind::MethodCall(_, rargs_self, ..) = &rhs.kind;
         then {
             span_lint_and_sugg(
                 cx,
@@ -621,7 +622,7 @@ fn check_log_division(cx: &LateContext<'_>, expr: &Expr<'_>) {
                 expr.span,
                 "log base can be expressed more clearly",
                 "consider using",
-                format!("{}.log({})", Sugg::hir(cx, largs_self, ".."), Sugg::hir(cx, rargs_self, ".."),),
+                format!("{}.log({})", Sugg::hir(cx, largs_self, "..").maybe_par(), Sugg::hir(cx, rargs_self, ".."),),
                 Applicability::MachineApplicable,
             );
         }
@@ -651,7 +652,7 @@ fn check_radians(cx: &LateContext<'_>, expr: &Expr<'_>) {
             if (F32(f32_consts::PI) == rvalue || F64(f64_consts::PI) == rvalue) &&
                (F32(180_f32) == lvalue || F64(180_f64) == lvalue)
             {
-                let mut proposal = format!("{}.to_degrees()", Sugg::hir(cx, mul_lhs, ".."));
+                let mut proposal = format!("{}.to_degrees()", Sugg::hir(cx, mul_lhs, "..").maybe_par());
                 if_chain! {
                     if let ExprKind::Lit(ref literal) = mul_lhs.kind;
                     if let ast::LitKind::Float(ref value, float_type) = literal.node;
@@ -677,7 +678,7 @@ fn check_radians(cx: &LateContext<'_>, expr: &Expr<'_>) {
                 (F32(180_f32) == rvalue || F64(180_f64) == rvalue) &&
                 (F32(f32_consts::PI) == lvalue || F64(f64_consts::PI) == lvalue)
             {
-                let mut proposal = format!("{}.to_radians()", Sugg::hir(cx, mul_lhs, ".."));
+                let mut proposal = format!("{}.to_radians()", Sugg::hir(cx, mul_lhs, "..").maybe_par());
                 if_chain! {
                     if let ExprKind::Lit(ref literal) = mul_lhs.kind;
                     if let ast::LitKind::Float(ref value, float_type) = literal.node;
@@ -711,16 +712,16 @@ impl<'tcx> LateLintPass<'tcx> for FloatingPointArithmetic {
             return;
         }
 
-        if let ExprKind::MethodCall(path, args, _) = &expr.kind {
-            let recv_ty = cx.typeck_results().expr_ty(&args[0]);
+        if let ExprKind::MethodCall(path, receiver, args, _) = &expr.kind {
+            let recv_ty = cx.typeck_results().expr_ty(receiver);
 
             if recv_ty.is_floating_point() {
                 match path.ident.name.as_str() {
-                    "ln" => check_ln1p(cx, expr, args),
-                    "log" => check_log_base(cx, expr, args),
-                    "powf" => check_powf(cx, expr, args),
-                    "powi" => check_powi(cx, expr, args),
-                    "sqrt" => check_hypot(cx, expr, args),
+                    "ln" => check_ln1p(cx, expr, receiver),
+                    "log" => check_log_base(cx, expr, receiver, args),
+                    "powf" => check_powf(cx, expr, receiver, args),
+                    "powi" => check_powi(cx, expr, receiver, args),
+                    "sqrt" => check_hypot(cx, expr, receiver),
                     _ => {},
                 }
             }
diff --git a/src/tools/clippy/clippy_lints/src/format.rs b/src/tools/clippy/clippy_lints/src/format.rs
index 925a8cb8deed..f10d82569536 100644
--- a/src/tools/clippy/clippy_lints/src/format.rs
+++ b/src/tools/clippy/clippy_lints/src/format.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::macros::{root_macro_call_first_node, FormatArgsExpn};
-use clippy_utils::source::{snippet_opt, snippet_with_applicability};
+use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::sugg::Sugg;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
@@ -56,29 +56,27 @@ impl<'tcx> LateLintPass<'tcx> for UselessFormat {
         };
 
         let mut applicability = Applicability::MachineApplicable;
-        if format_args.value_args.is_empty() {
-            match *format_args.format_string_parts {
+        if format_args.args.is_empty() {
+            match *format_args.format_string.parts {
                 [] => span_useless_format_empty(cx, call_site, "String::new()".to_owned(), applicability),
                 [_] => {
-                    if let Some(s_src) = snippet_opt(cx, format_args.format_string_span) {
-                        // Simulate macro expansion, converting {{ and }} to { and }.
-                        let s_expand = s_src.replace("{{", "{").replace("}}", "}");
-                        let sugg = format!("{}.to_string()", s_expand);
-                        span_useless_format(cx, call_site, sugg, applicability);
-                    }
+                    // Simulate macro expansion, converting {{ and }} to { and }.
+                    let s_expand = format_args.format_string.snippet.replace("{{", "{").replace("}}", "}");
+                    let sugg = format!("{}.to_string()", s_expand);
+                    span_useless_format(cx, call_site, sugg, applicability);
                 },
                 [..] => {},
             }
-        } else if let [value] = *format_args.value_args {
+        } else if let [arg] = &*format_args.args {
+            let value = arg.param.value;
             if_chain! {
-                if format_args.format_string_parts == [kw::Empty];
+                if format_args.format_string.parts == [kw::Empty];
+                if arg.format.is_default();
                 if match cx.typeck_results().expr_ty(value).peel_refs().kind() {
                     ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(sym::String, adt.did()),
                     ty::Str => true,
                     _ => false,
                 };
-                if let Some(args) = format_args.args();
-                if args.iter().all(|arg| arg.format_trait == sym::Display && !arg.has_string_formatting());
                 then {
                     let is_new_string = match value.kind {
                         ExprKind::Binary(..) => true,
diff --git a/src/tools/clippy/clippy_lints/src/format_args.rs b/src/tools/clippy/clippy_lints/src/format_args.rs
index 1e6feaac26c3..9e1eaf248b73 100644
--- a/src/tools/clippy/clippy_lints/src/format_args.rs
+++ b/src/tools/clippy/clippy_lints/src/format_args.rs
@@ -1,11 +1,12 @@
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::is_diag_trait_item;
-use clippy_utils::macros::{is_format_macro, FormatArgsArg, FormatArgsExpn};
+use clippy_utils::macros::{is_format_macro, FormatArgsExpn};
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::implements_trait;
 use if_chain::if_chain;
+use itertools::Itertools;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
+use rustc_hir::{Expr, ExprKind, HirId};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment};
 use rustc_middle::ty::Ty;
@@ -74,20 +75,16 @@ impl<'tcx> LateLintPass<'tcx> for FormatArgs {
             if let Some(macro_def_id) = outermost_expn_data.macro_def_id;
             if is_format_macro(cx, macro_def_id);
             if let ExpnKind::Macro(_, name) = outermost_expn_data.kind;
-            if let Some(args) = format_args.args();
             then {
-                for (i, arg) in args.iter().enumerate() {
-                    if arg.format_trait != sym::Display {
+                for arg in &format_args.args {
+                    if !arg.format.is_default() {
                         continue;
                     }
-                    if arg.has_string_formatting() {
+                    if is_aliased(&format_args, arg.param.value.hir_id) {
                         continue;
                     }
-                    if is_aliased(&args, i) {
-                        continue;
-                    }
-                    check_format_in_format_args(cx, outermost_expn_data.call_site, name, arg.value);
-                    check_to_string_in_format_args(cx, name, arg.value);
+                    check_format_in_format_args(cx, outermost_expn_data.call_site, name, arg.param.value);
+                    check_to_string_in_format_args(cx, name, arg.param.value);
                 }
             }
         }
@@ -102,7 +99,12 @@ fn outermost_expn_data(expn_data: ExpnData) -> ExpnData {
     }
 }
 
-fn check_format_in_format_args(cx: &LateContext<'_>, call_site: Span, name: Symbol, arg: &Expr<'_>) {
+fn check_format_in_format_args(
+    cx: &LateContext<'_>,
+    call_site: Span,
+    name: Symbol,
+    arg: &Expr<'_>,
+) {
     let expn_data = arg.span.ctxt().outer_expn_data();
     if expn_data.call_site.from_expansion() {
         return;
@@ -129,50 +131,58 @@ fn check_format_in_format_args(cx: &LateContext<'_>, call_site: Span, name: Symb
 fn check_to_string_in_format_args(cx: &LateContext<'_>, name: Symbol, value: &Expr<'_>) {
     if_chain! {
         if !value.span.from_expansion();
-        if let ExprKind::MethodCall(_, [receiver], _) = value.kind;
+        if let ExprKind::MethodCall(_, receiver, [], _) = value.kind;
         if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(value.hir_id);
         if is_diag_trait_item(cx, method_def_id, sym::ToString);
         let receiver_ty = cx.typeck_results().expr_ty(receiver);
         if let Some(display_trait_id) = cx.tcx.get_diagnostic_item(sym::Display);
+        let (n_needed_derefs, target) =
+            count_needed_derefs(receiver_ty, cx.typeck_results().expr_adjustments(receiver).iter());
+        if implements_trait(cx, target, display_trait_id, &[]);
+        if let Some(sized_trait_id) = cx.tcx.lang_items().sized_trait();
         if let Some(receiver_snippet) = snippet_opt(cx, receiver.span);
         then {
-            let (n_needed_derefs, target) = count_needed_derefs(
-                receiver_ty,
-                cx.typeck_results().expr_adjustments(receiver).iter(),
-            );
-            if implements_trait(cx, target, display_trait_id, &[]) {
-                if n_needed_derefs == 0 {
-                    span_lint_and_sugg(
-                        cx,
-                        TO_STRING_IN_FORMAT_ARGS,
-                        value.span.with_lo(receiver.span.hi()),
-                        &format!("`to_string` applied to a type that implements `Display` in `{}!` args", name),
-                        "remove this",
-                        String::new(),
-                        Applicability::MachineApplicable,
-                    );
-                } else {
-                    span_lint_and_sugg(
-                        cx,
-                        TO_STRING_IN_FORMAT_ARGS,
-                        value.span,
-                        &format!("`to_string` applied to a type that implements `Display` in `{}!` args", name),
-                        "use this",
-                        format!("{:*>width$}{}", "", receiver_snippet, width = n_needed_derefs),
-                        Applicability::MachineApplicable,
-                    );
-                }
+            let needs_ref = !implements_trait(cx, receiver_ty, sized_trait_id, &[]);
+            if n_needed_derefs == 0 && !needs_ref {
+                span_lint_and_sugg(
+                    cx,
+                    TO_STRING_IN_FORMAT_ARGS,
+                    value.span.with_lo(receiver.span.hi()),
+                    &format!(
+                        "`to_string` applied to a type that implements `Display` in `{}!` args",
+                        name
+                    ),
+                    "remove this",
+                    String::new(),
+                    Applicability::MachineApplicable,
+                );
+            } else {
+                span_lint_and_sugg(
+                    cx,
+                    TO_STRING_IN_FORMAT_ARGS,
+                    value.span,
+                    &format!(
+                        "`to_string` applied to a type that implements `Display` in `{}!` args",
+                        name
+                    ),
+                    "use this",
+                    format!(
+                        "{}{:*>width$}{}",
+                        if needs_ref { "&" } else { "" },
+                        "",
+                        receiver_snippet,
+                        width = n_needed_derefs
+                    ),
+                    Applicability::MachineApplicable,
+                );
             }
         }
     }
 }
 
-// Returns true if `args[i]` "refers to" or "is referred to by" another argument.
-fn is_aliased(args: &[FormatArgsArg<'_>], i: usize) -> bool {
-    let value = args[i].value;
-    args.iter()
-        .enumerate()
-        .any(|(j, arg)| i != j && std::ptr::eq(value, arg.value))
+// Returns true if `hir_id` is referred to by multiple format params
+fn is_aliased(args: &FormatArgsExpn<'_>, hir_id: HirId) -> bool {
+    args.params().filter(|param| param.value.hir_id == hir_id).at_most_one().is_err()
 }
 
 fn count_needed_derefs<'tcx, I>(mut ty: Ty<'tcx>, mut iter: I) -> (usize, Ty<'tcx>)
@@ -182,11 +192,7 @@ where
     let mut n_total = 0;
     let mut n_needed = 0;
     loop {
-        if let Some(Adjustment {
-            kind: Adjust::Deref(overloaded_deref),
-            target,
-        }) = iter.next()
-        {
+        if let Some(Adjustment { kind: Adjust::Deref(overloaded_deref), target }) = iter.next() {
             n_total += 1;
             if overloaded_deref.is_some() {
                 n_needed = n_total;
diff --git a/src/tools/clippy/clippy_lints/src/format_impl.rs b/src/tools/clippy/clippy_lints/src/format_impl.rs
index 04b5be6c80ec..b628fd9f7581 100644
--- a/src/tools/clippy/clippy_lints/src/format_impl.rs
+++ b/src/tools/clippy/clippy_lints/src/format_impl.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
-use clippy_utils::macros::{is_format_macro, root_macro_call_first_node, FormatArgsArg, FormatArgsExpn};
+use clippy_utils::macros::{is_format_macro, root_macro_call_first_node, FormatArg, FormatArgsExpn};
 use clippy_utils::{get_parent_as_impl, is_diag_trait_item, path_to_local, peel_ref_operators};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
@@ -139,7 +139,7 @@ impl<'tcx> LateLintPass<'tcx> for FormatImpl {
 fn check_to_string_in_display(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
         // Get the hir_id of the object we are calling the method on
-        if let ExprKind::MethodCall(path, [ref self_arg, ..], _) = expr.kind;
+        if let ExprKind::MethodCall(path, self_arg, ..) = expr.kind;
         // Is the method to_string() ?
         if path.ident.name == sym::to_string;
         // Is the method a part of the ToString trait? (i.e. not to_string() implemented
@@ -168,10 +168,9 @@ fn check_self_in_format_args<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>,
         if let macro_def_id = outer_macro.def_id;
         if let Some(format_args) = FormatArgsExpn::find_nested(cx, expr, outer_macro.expn);
         if is_format_macro(cx, macro_def_id);
-        if let Some(args) = format_args.args();
         then {
-            for arg in args {
-                if arg.format_trait != impl_trait.name {
+            for arg in format_args.args {
+                if arg.format.r#trait != impl_trait.name {
                     continue;
                 }
                 check_format_arg_self(cx, expr, &arg, impl_trait);
@@ -180,11 +179,11 @@ fn check_self_in_format_args<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>,
     }
 }
 
-fn check_format_arg_self(cx: &LateContext<'_>, expr: &Expr<'_>, arg: &FormatArgsArg<'_>, impl_trait: FormatTrait) {
+fn check_format_arg_self(cx: &LateContext<'_>, expr: &Expr<'_>, arg: &FormatArg<'_>, impl_trait: FormatTrait) {
     // Handle multiple dereferencing of references e.g. &&self
     // Handle dereference of &self -> self that is equivalent (i.e. via *self in fmt() impl)
     // Since the argument to fmt is itself a reference: &self
-    let reference = peel_ref_operators(cx, arg.value);
+    let reference = peel_ref_operators(cx, arg.param.value);
     let map = cx.tcx.hir();
     // Is the reference self?
     if path_to_local(reference).map(|x| map.name(x)) == Some(kw::SelfLower) {
diff --git a/src/tools/clippy/clippy_lints/src/format_push_string.rs b/src/tools/clippy/clippy_lints/src/format_push_string.rs
index ebf5ab086dce..9b9f1872bfc1 100644
--- a/src/tools/clippy/clippy_lints/src/format_push_string.rs
+++ b/src/tools/clippy/clippy_lints/src/format_push_string.rs
@@ -54,7 +54,7 @@ fn is_format(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
 impl<'tcx> LateLintPass<'tcx> for FormatPushString {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         let arg = match expr.kind {
-            ExprKind::MethodCall(_, [_, arg], _) => {
+            ExprKind::MethodCall(_, _, [arg], _) => {
                 if let Some(fn_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) &&
                 match_def_path(cx, fn_def_id, &paths::PUSH_STR) {
                     arg
diff --git a/src/tools/clippy/clippy_lints/src/functions/mod.rs b/src/tools/clippy/clippy_lints/src/functions/mod.rs
index 73261fb8a44c..90911e0bf259 100644
--- a/src/tools/clippy/clippy_lints/src/functions/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/mod.rs
@@ -1,6 +1,6 @@
 mod must_use;
 mod not_unsafe_ptr_arg_deref;
-mod result_unit_err;
+mod result;
 mod too_many_arguments;
 mod too_many_lines;
 
@@ -217,17 +217,62 @@ declare_clippy_lint! {
     "public function returning `Result` with an `Err` type of `()`"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for functions that return `Result` with an unusually large
+    /// `Err`-variant.
+    ///
+    /// ### Why is this bad?
+    /// A `Result` is at least as large as the `Err`-variant. While we
+    /// expect that variant to be seldomly used, the compiler needs to reserve
+    /// and move that much memory every single time.
+    ///
+    /// ### Known problems
+    /// The size determined by Clippy is platform-dependent.
+    ///
+    /// ### Examples
+    /// ```rust
+    /// pub enum ParseError {
+    ///     UnparsedBytes([u8; 512]),
+    ///     UnexpectedEof,
+    /// }
+    ///
+    /// // The `Result` has at least 512 bytes, even in the `Ok`-case
+    /// pub fn parse() -> Result<(), ParseError> {
+    ///     Ok(())
+    /// }
+    /// ```
+    /// should be
+    /// ```
+    /// pub enum ParseError {
+    ///     UnparsedBytes(Box<[u8; 512]>),
+    ///     UnexpectedEof,
+    /// }
+    ///
+    /// // The `Result` is slightly larger than a pointer
+    /// pub fn parse() -> Result<(), ParseError> {
+    ///     Ok(())
+    /// }
+    /// ```
+    #[clippy::version = "1.64.0"]
+    pub RESULT_LARGE_ERR,
+    perf,
+    "function returning `Result` with large `Err` type"
+}
+
 #[derive(Copy, Clone)]
 pub struct Functions {
     too_many_arguments_threshold: u64,
     too_many_lines_threshold: u64,
+    large_error_threshold: u64,
 }
 
 impl Functions {
-    pub fn new(too_many_arguments_threshold: u64, too_many_lines_threshold: u64) -> Self {
+    pub fn new(too_many_arguments_threshold: u64, too_many_lines_threshold: u64, large_error_threshold: u64) -> Self {
         Self {
             too_many_arguments_threshold,
             too_many_lines_threshold,
+            large_error_threshold,
         }
     }
 }
@@ -240,6 +285,7 @@ impl_lint_pass!(Functions => [
     DOUBLE_MUST_USE,
     MUST_USE_CANDIDATE,
     RESULT_UNIT_ERR,
+    RESULT_LARGE_ERR,
 ]);
 
 impl<'tcx> LateLintPass<'tcx> for Functions {
@@ -259,18 +305,18 @@ impl<'tcx> LateLintPass<'tcx> for Functions {
 
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
         must_use::check_item(cx, item);
-        result_unit_err::check_item(cx, item);
+        result::check_item(cx, item, self.large_error_threshold);
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'_>) {
         must_use::check_impl_item(cx, item);
-        result_unit_err::check_impl_item(cx, item);
+        result::check_impl_item(cx, item, self.large_error_threshold);
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) {
         too_many_arguments::check_trait_item(cx, item, self.too_many_arguments_threshold);
         not_unsafe_ptr_arg_deref::check_trait_item(cx, item);
         must_use::check_trait_item(cx, item);
-        result_unit_err::check_trait_item(cx, item);
+        result::check_trait_item(cx, item, self.large_error_threshold);
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/functions/must_use.rs b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
index 6672a6cb0b58..d6d33bda1738 100644
--- a/src/tools/clippy/clippy_lints/src/functions/must_use.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
@@ -21,7 +21,7 @@ pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>
     let attrs = cx.tcx.hir().attrs(item.hir_id());
     let attr = cx.tcx.get_attr(item.def_id.to_def_id(), sym::must_use);
     if let hir::ItemKind::Fn(ref sig, _generics, ref body_id) = item.kind {
-        let is_public = cx.access_levels.is_exported(item.def_id);
+        let is_public = cx.access_levels.is_exported(item.def_id.def_id);
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
         if let Some(attr) = attr {
             check_needless_must_use(cx, sig.decl, item.hir_id(), item.span, fn_header_span, attr);
@@ -31,7 +31,7 @@ pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>
                 sig.decl,
                 cx.tcx.hir().body(*body_id),
                 item.span,
-                item.def_id,
+                item.def_id.def_id,
                 item.span.with_hi(sig.decl.output.span().hi()),
                 "this function could have a `#[must_use]` attribute",
             );
@@ -41,19 +41,19 @@ pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>
 
 pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'_>) {
     if let hir::ImplItemKind::Fn(ref sig, ref body_id) = item.kind {
-        let is_public = cx.access_levels.is_exported(item.def_id);
+        let is_public = cx.access_levels.is_exported(item.def_id.def_id);
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
         let attrs = cx.tcx.hir().attrs(item.hir_id());
         let attr = cx.tcx.get_attr(item.def_id.to_def_id(), sym::must_use);
         if let Some(attr) = attr {
             check_needless_must_use(cx, sig.decl, item.hir_id(), item.span, fn_header_span, attr);
-        } else if is_public && !is_proc_macro(cx.sess(), attrs) && trait_ref_of_method(cx, item.def_id).is_none() {
+        } else if is_public && !is_proc_macro(cx.sess(), attrs) && trait_ref_of_method(cx, item.def_id.def_id).is_none() {
             check_must_use_candidate(
                 cx,
                 sig.decl,
                 cx.tcx.hir().body(*body_id),
                 item.span,
-                item.def_id,
+                item.def_id.def_id,
                 item.span.with_hi(sig.decl.output.span().hi()),
                 "this method could have a `#[must_use]` attribute",
             );
@@ -63,7 +63,7 @@ pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Imp
 
 pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) {
     if let hir::TraitItemKind::Fn(ref sig, ref eid) = item.kind {
-        let is_public = cx.access_levels.is_exported(item.def_id);
+        let is_public = cx.access_levels.is_exported(item.def_id.def_id);
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
 
         let attrs = cx.tcx.hir().attrs(item.hir_id());
@@ -78,7 +78,7 @@ pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Tr
                     sig.decl,
                     body,
                     item.span,
-                    item.def_id,
+                    item.def_id.def_id,
                     item.span.with_hi(sig.decl.output.span().hi()),
                     "this method could have a `#[must_use]` attribute",
                 );
@@ -171,7 +171,7 @@ fn is_mutable_pat(cx: &LateContext<'_>, pat: &hir::Pat<'_>, tys: &mut DefIdSet)
         return false; // ignore `_` patterns
     }
     if cx.tcx.has_typeck_results(pat.hir_id.owner.to_def_id()) {
-        is_mutable_ty(cx, cx.tcx.typeck(pat.hir_id.owner).pat_ty(pat), pat.span, tys)
+        is_mutable_ty(cx, cx.tcx.typeck(pat.hir_id.owner.def_id).pat_ty(pat), pat.span, tys)
     } else {
         false
     }
@@ -212,13 +212,31 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for StaticMutVisitor<'a, 'tcx> {
             return;
         }
         match expr.kind {
-            Call(_, args) | MethodCall(_, args, _) => {
+            Call(_, args) => {
                 let mut tys = DefIdSet::default();
                 for arg in args {
                     if self.cx.tcx.has_typeck_results(arg.hir_id.owner.to_def_id())
                         && is_mutable_ty(
                             self.cx,
-                            self.cx.tcx.typeck(arg.hir_id.owner).expr_ty(arg),
+                            self.cx.tcx.typeck(arg.hir_id.owner.def_id).expr_ty(arg),
+                            arg.span,
+                            &mut tys,
+                        )
+                        && is_mutated_static(arg)
+                    {
+                        self.mutates_static = true;
+                        return;
+                    }
+                    tys.clear();
+                }
+            },
+            MethodCall(_, receiver, args, _) => {
+                let mut tys = DefIdSet::default();
+                for arg in std::iter::once(receiver).chain(args.iter()) {
+                    if self.cx.tcx.has_typeck_results(arg.hir_id.owner.to_def_id())
+                        && is_mutable_ty(
+                            self.cx,
+                            self.cx.tcx.typeck(arg.hir_id.owner.def_id).expr_ty(arg),
                             arg.span,
                             &mut tys,
                         )
@@ -254,6 +272,6 @@ fn mutates_static<'tcx>(cx: &LateContext<'tcx>, body: &'tcx hir::Body<'_>) -> bo
         cx,
         mutates_static: false,
     };
-    intravisit::walk_expr(&mut v, &body.value);
+    intravisit::walk_expr(&mut v, body.value);
     v.mutates_static
 }
diff --git a/src/tools/clippy/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs b/src/tools/clippy/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs
index 565a1c871d75..0b50431fbaab 100644
--- a/src/tools/clippy/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/not_unsafe_ptr_arg_deref.rs
@@ -28,7 +28,7 @@ pub(super) fn check_fn<'tcx>(
 pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) {
     if let hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(eid)) = item.kind {
         let body = cx.tcx.hir().body(eid);
-        check_raw_ptr(cx, sig.header.unsafety, sig.decl, body, item.def_id);
+        check_raw_ptr(cx, sig.header.unsafety, sig.decl, body, item.def_id.def_id);
     }
 }
 
@@ -88,11 +88,12 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for DerefVisitor<'a, 'tcx> {
                     }
                 }
             },
-            hir::ExprKind::MethodCall(_, args, _) => {
+            hir::ExprKind::MethodCall(_, receiver, args, _) => {
                 let def_id = self.typeck_results.type_dependent_def_id(expr.hir_id).unwrap();
                 let base_type = self.cx.tcx.type_of(def_id);
 
                 if type_is_unsafe_function(self.cx, base_type) {
+                    self.check_arg(receiver);
                     for arg in args {
                         self.check_arg(arg);
                     }
diff --git a/src/tools/clippy/clippy_lints/src/functions/result.rs b/src/tools/clippy/clippy_lints/src/functions/result.rs
new file mode 100644
index 000000000000..113c4e9f5091
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/functions/result.rs
@@ -0,0 +1,100 @@
+use rustc_errors::Diagnostic;
+use rustc_hir as hir;
+use rustc_lint::{LateContext, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_middle::ty::{self, Ty};
+use rustc_span::{sym, Span};
+
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_then};
+use clippy_utils::trait_ref_of_method;
+use clippy_utils::ty::{approx_ty_size, is_type_diagnostic_item};
+
+use super::{RESULT_LARGE_ERR, RESULT_UNIT_ERR};
+
+/// The type of the `Err`-variant in a `std::result::Result` returned by the
+/// given `FnDecl`
+fn result_err_ty<'tcx>(
+    cx: &LateContext<'tcx>,
+    decl: &hir::FnDecl<'tcx>,
+    id: hir::def_id::LocalDefId,
+    item_span: Span,
+) -> Option<(&'tcx hir::Ty<'tcx>, Ty<'tcx>)> {
+    if !in_external_macro(cx.sess(), item_span)
+        && let hir::FnRetTy::Return(hir_ty) = decl.output
+        && let ty = cx.tcx.erase_late_bound_regions(cx.tcx.fn_sig(id).output())
+        && is_type_diagnostic_item(cx, ty, sym::Result)
+        && let ty::Adt(_, substs) = ty.kind()
+    {
+        let err_ty = substs.type_at(1);
+        Some((hir_ty, err_ty))
+    } else {
+        None
+    }
+}
+
+pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &hir::Item<'tcx>, large_err_threshold: u64) {
+    if let hir::ItemKind::Fn(ref sig, _generics, _) = item.kind
+        && let Some((hir_ty, err_ty)) = result_err_ty(cx, sig.decl, item.def_id.def_id, item.span)
+    {
+        if cx.access_levels.is_exported(item.def_id.def_id) {
+            let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
+            check_result_unit_err(cx, err_ty, fn_header_span);
+        }
+        check_result_large_err(cx, err_ty, hir_ty.span, large_err_threshold);
+    }
+}
+
+pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &hir::ImplItem<'tcx>, large_err_threshold: u64) {
+    // Don't lint if method is a trait's implementation, we can't do anything about those
+    if let hir::ImplItemKind::Fn(ref sig, _) = item.kind
+        && let Some((hir_ty, err_ty)) = result_err_ty(cx, sig.decl, item.def_id.def_id, item.span)
+        && trait_ref_of_method(cx, item.def_id.def_id).is_none()
+    {
+        if cx.access_levels.is_exported(item.def_id.def_id) {
+            let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
+            check_result_unit_err(cx, err_ty, fn_header_span);
+        }
+        check_result_large_err(cx, err_ty, hir_ty.span, large_err_threshold);
+    }
+}
+
+pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &hir::TraitItem<'tcx>, large_err_threshold: u64) {
+    if let hir::TraitItemKind::Fn(ref sig, _) = item.kind {
+        let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
+        if let Some((hir_ty, err_ty)) = result_err_ty(cx, sig.decl, item.def_id.def_id, item.span) {
+            if cx.access_levels.is_exported(item.def_id.def_id) {
+                check_result_unit_err(cx, err_ty, fn_header_span);
+            }
+            check_result_large_err(cx, err_ty, hir_ty.span, large_err_threshold);
+        }
+    }
+}
+
+fn check_result_unit_err(cx: &LateContext<'_>, err_ty: Ty<'_>, fn_header_span: Span) {
+    if err_ty.is_unit() {
+        span_lint_and_help(
+            cx,
+            RESULT_UNIT_ERR,
+            fn_header_span,
+            "this returns a `Result<_, ()>`",
+            None,
+            "use a custom `Error` type instead",
+        );
+    }
+}
+
+fn check_result_large_err<'tcx>(cx: &LateContext<'tcx>, err_ty: Ty<'tcx>, hir_ty_span: Span, large_err_threshold: u64) {
+    let ty_size = approx_ty_size(cx, err_ty);
+    if ty_size >= large_err_threshold {
+        span_lint_and_then(
+            cx,
+            RESULT_LARGE_ERR,
+            hir_ty_span,
+            "the `Err`-variant returned from this function is very large",
+            |diag: &mut Diagnostic| {
+                diag.span_label(hir_ty_span, format!("the `Err`-variant is at least {ty_size} bytes"));
+                diag.help(format!("try reducing the size of `{err_ty}`, for example by boxing large elements or replacing it with `Box<{err_ty}>`"));
+            },
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/functions/result_unit_err.rs b/src/tools/clippy/clippy_lints/src/functions/result_unit_err.rs
deleted file mode 100644
index 2e63a1f920d6..000000000000
--- a/src/tools/clippy/clippy_lints/src/functions/result_unit_err.rs
+++ /dev/null
@@ -1,66 +0,0 @@
-use rustc_hir as hir;
-use rustc_lint::{LateContext, LintContext};
-use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty;
-use rustc_span::{sym, Span};
-use rustc_typeck::hir_ty_to_ty;
-
-use if_chain::if_chain;
-
-use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::trait_ref_of_method;
-use clippy_utils::ty::is_type_diagnostic_item;
-
-use super::RESULT_UNIT_ERR;
-
-pub(super) fn check_item(cx: &LateContext<'_>, item: &hir::Item<'_>) {
-    if let hir::ItemKind::Fn(ref sig, _generics, _) = item.kind {
-        let is_public = cx.access_levels.is_exported(item.def_id);
-        let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
-        if is_public {
-            check_result_unit_err(cx, sig.decl, item.span, fn_header_span);
-        }
-    }
-}
-
-pub(super) fn check_impl_item(cx: &LateContext<'_>, item: &hir::ImplItem<'_>) {
-    if let hir::ImplItemKind::Fn(ref sig, _) = item.kind {
-        let is_public = cx.access_levels.is_exported(item.def_id);
-        let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
-        if is_public && trait_ref_of_method(cx, item.def_id).is_none() {
-            check_result_unit_err(cx, sig.decl, item.span, fn_header_span);
-        }
-    }
-}
-
-pub(super) fn check_trait_item(cx: &LateContext<'_>, item: &hir::TraitItem<'_>) {
-    if let hir::TraitItemKind::Fn(ref sig, _) = item.kind {
-        let is_public = cx.access_levels.is_exported(item.def_id);
-        let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
-        if is_public {
-            check_result_unit_err(cx, sig.decl, item.span, fn_header_span);
-        }
-    }
-}
-
-fn check_result_unit_err(cx: &LateContext<'_>, decl: &hir::FnDecl<'_>, item_span: Span, fn_header_span: Span) {
-    if_chain! {
-        if !in_external_macro(cx.sess(), item_span);
-        if let hir::FnRetTy::Return(ty) = decl.output;
-        let ty = hir_ty_to_ty(cx.tcx, ty);
-        if is_type_diagnostic_item(cx, ty, sym::Result);
-        if let ty::Adt(_, substs) = ty.kind();
-        let err_ty = substs.type_at(1);
-        if err_ty.is_unit();
-        then {
-            span_lint_and_help(
-                cx,
-                RESULT_UNIT_ERR,
-                fn_header_span,
-                "this returns a `Result<_, ()>`",
-                None,
-                "use a custom `Error` type instead",
-            );
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/future_not_send.rs b/src/tools/clippy/clippy_lints/src/future_not_send.rs
index ef7d75aa8ed9..eb2eefe0d5a1 100644
--- a/src/tools/clippy/clippy_lints/src/future_not_send.rs
+++ b/src/tools/clippy/clippy_lints/src/future_not_send.rs
@@ -4,7 +4,6 @@ use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, FnDecl, HirId};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{EarlyBinder, Opaque, PredicateKind::Trait};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, Span};
diff --git a/src/tools/clippy/clippy_lints/src/get_first.rs b/src/tools/clippy/clippy_lints/src/get_first.rs
deleted file mode 100644
index 529f7babaa5e..000000000000
--- a/src/tools/clippy/clippy_lints/src/get_first.rs
+++ /dev/null
@@ -1,68 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{is_slice_of_primitives, match_def_path, paths};
-use if_chain::if_chain;
-use rustc_ast::LitKind;
-use rustc_errors::Applicability;
-use rustc_hir as hir;
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::source_map::Spanned;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for using `x.get(0)` instead of
-    /// `x.first()`.
-    ///
-    /// ### Why is this bad?
-    /// Using `x.first()` is easier to read and has the same
-    /// result.
-    ///
-    /// ### Example
-    /// ```rust
-    /// let x = vec![2, 3, 5];
-    /// let first_element = x.get(0);
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust
-    /// let x = vec![2, 3, 5];
-    /// let first_element = x.first();
-    /// ```
-    #[clippy::version = "1.63.0"]
-    pub GET_FIRST,
-    style,
-    "Using `x.get(0)` when `x.first()` is simpler"
-}
-declare_lint_pass!(GetFirst => [GET_FIRST]);
-
-impl<'tcx> LateLintPass<'tcx> for GetFirst {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if_chain! {
-            if let hir::ExprKind::MethodCall(_, [struct_calling_on, method_arg], _) = &expr.kind;
-            if let Some(expr_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
-            if match_def_path(cx, expr_def_id, &paths::SLICE_GET);
-
-            if let Some(_) = is_slice_of_primitives(cx, struct_calling_on);
-            if let hir::ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = method_arg.kind;
-
-            then {
-                let mut applicability = Applicability::MachineApplicable;
-                let slice_name = snippet_with_applicability(
-                    cx,
-                    struct_calling_on.span, "..",
-                    &mut applicability,
-                );
-                span_lint_and_sugg(
-                    cx,
-                    GET_FIRST,
-                    expr.span,
-                    &format!("accessing first element with `{0}.get(0)`", slice_name),
-                    "try",
-                    format!("{}.first()", slice_name),
-                    applicability,
-                );
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/if_let_mutex.rs b/src/tools/clippy/clippy_lints/src/if_let_mutex.rs
index e95017007849..9ea8c494cfcd 100644
--- a/src/tools/clippy/clippy_lints/src/if_let_mutex.rs
+++ b/src/tools/clippy/clippy_lints/src/if_let_mutex.rs
@@ -1,8 +1,9 @@
-use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::higher;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::SpanlessEq;
 use if_chain::if_chain;
+use rustc_errors::Diagnostic;
 use rustc_hir::intravisit::{self as visit, Visitor};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -45,16 +46,8 @@ declare_lint_pass!(IfLetMutex => [IF_LET_MUTEX]);
 
 impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        let mut arm_visit = ArmVisitor {
-            mutex_lock_called: false,
-            found_mutex: None,
-            cx,
-        };
-        let mut op_visit = OppVisitor {
-            mutex_lock_called: false,
-            found_mutex: None,
-            cx,
-        };
+        let mut arm_visit = ArmVisitor { found_mutex: None, cx };
+        let mut op_visit = OppVisitor { found_mutex: None, cx };
         if let Some(higher::IfLet {
             let_expr,
             if_then,
@@ -63,18 +56,28 @@ impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
         }) = higher::IfLet::hir(cx, expr)
         {
             op_visit.visit_expr(let_expr);
-            if op_visit.mutex_lock_called {
+            if let Some(op_mutex) = op_visit.found_mutex {
                 arm_visit.visit_expr(if_then);
                 arm_visit.visit_expr(if_else);
 
-                if arm_visit.mutex_lock_called && arm_visit.same_mutex(cx, op_visit.found_mutex.unwrap()) {
-                    span_lint_and_help(
+                if let Some(arm_mutex) = arm_visit.found_mutex_if_same_as(op_mutex) {
+                    let diag = |diag: &mut Diagnostic| {
+                        diag.span_label(
+                            op_mutex.span,
+                            "this Mutex will remain locked for the entire `if let`-block...",
+                        );
+                        diag.span_label(
+                            arm_mutex.span,
+                            "... and is tried to lock again here, which will always deadlock.",
+                        );
+                        diag.help("move the lock call outside of the `if let ...` expression");
+                    };
+                    span_lint_and_then(
                         cx,
                         IF_LET_MUTEX,
                         expr.span,
                         "calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a deadlock",
-                        None,
-                        "move the lock call outside of the `if let ...` expression",
+                        diag,
                     );
                 }
             }
@@ -84,7 +87,6 @@ impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
 
 /// Checks if `Mutex::lock` is called in the `if let` expr.
 pub struct OppVisitor<'a, 'tcx> {
-    mutex_lock_called: bool,
     found_mutex: Option<&'tcx Expr<'tcx>>,
     cx: &'a LateContext<'tcx>,
 }
@@ -93,7 +95,6 @@ impl<'tcx> Visitor<'tcx> for OppVisitor<'_, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
         if let Some(mutex) = is_mutex_lock_call(self.cx, expr) {
             self.found_mutex = Some(mutex);
-            self.mutex_lock_called = true;
             return;
         }
         visit::walk_expr(self, expr);
@@ -102,7 +103,6 @@ impl<'tcx> Visitor<'tcx> for OppVisitor<'_, 'tcx> {
 
 /// Checks if `Mutex::lock` is called in any of the branches.
 pub struct ArmVisitor<'a, 'tcx> {
-    mutex_lock_called: bool,
     found_mutex: Option<&'tcx Expr<'tcx>>,
     cx: &'a LateContext<'tcx>,
 }
@@ -111,7 +111,6 @@ impl<'tcx> Visitor<'tcx> for ArmVisitor<'_, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
         if let Some(mutex) = is_mutex_lock_call(self.cx, expr) {
             self.found_mutex = Some(mutex);
-            self.mutex_lock_called = true;
             return;
         }
         visit::walk_expr(self, expr);
@@ -119,17 +118,20 @@ impl<'tcx> Visitor<'tcx> for ArmVisitor<'_, 'tcx> {
 }
 
 impl<'tcx, 'l> ArmVisitor<'tcx, 'l> {
-    fn same_mutex(&self, cx: &LateContext<'_>, op_mutex: &Expr<'_>) -> bool {
-        self.found_mutex
-            .map_or(false, |arm_mutex| SpanlessEq::new(cx).eq_expr(op_mutex, arm_mutex))
+    fn found_mutex_if_same_as(&self, op_mutex: &Expr<'_>) -> Option<&Expr<'_>> {
+        self.found_mutex.and_then(|arm_mutex| {
+            SpanlessEq::new(self.cx)
+                .eq_expr(op_mutex, arm_mutex)
+                .then_some(arm_mutex)
+        })
     }
 }
 
 fn is_mutex_lock_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
     if_chain! {
-        if let ExprKind::MethodCall(path, [self_arg, ..], _) = &expr.kind;
+        if let ExprKind::MethodCall(path, self_arg, ..) = &expr.kind;
         if path.ident.as_str() == "lock";
-        let ty = cx.typeck_results().expr_ty(self_arg);
+        let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
         if is_type_diagnostic_item(cx, ty, sym::Mutex);
         then {
             Some(self_arg)
diff --git a/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs b/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs
index b8d227855d97..11c43247868c 100644
--- a/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs
+++ b/src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs
@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::eager_or_lazy::switch_to_eager_eval;
 use clippy_utils::source::snippet_with_macro_callsite;
 use clippy_utils::{contains_return, higher, is_else_clause, is_lang_ctor, meets_msrv, msrvs, peel_blocks};
-use if_chain::if_chain;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_hir::{Expr, ExprKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -11,10 +11,12 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for if-else that could be written to `bool::then`.
+    /// Checks for if-else that could be written using either `bool::then` or `bool::then_some`.
     ///
     /// ### Why is this bad?
-    /// Looks a little redundant. Using `bool::then` helps it have less lines of code.
+    /// Looks a little redundant. Using `bool::then` is more concise and incurs no loss of clarity.
+    /// For simple calculations and known values, use `bool::then_some`, which is eagerly evaluated
+    /// in comparison to `bool::then`.
     ///
     /// ### Example
     /// ```rust
@@ -39,7 +41,7 @@ declare_clippy_lint! {
     #[clippy::version = "1.53.0"]
     pub IF_THEN_SOME_ELSE_NONE,
     restriction,
-    "Finds if-else that could be written using `bool::then`"
+    "Finds if-else that could be written using either `bool::then` or `bool::then_some`"
 }
 
 pub struct IfThenSomeElseNone {
@@ -56,7 +58,7 @@ impl IfThenSomeElseNone {
 impl_lint_pass!(IfThenSomeElseNone => [IF_THEN_SOME_ELSE_NONE]);
 
 impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'tcx Expr<'_>) {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         if !meets_msrv(self.msrv, msrvs::BOOL_THEN) {
             return;
         }
@@ -70,43 +72,47 @@ impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
             return;
         }
 
-        if_chain! {
-            if let Some(higher::If { cond, then, r#else: Some(els) }) = higher::If::hir(expr);
-            if let ExprKind::Block(then_block, _) = then.kind;
-            if let Some(then_expr) = then_block.expr;
-            if let ExprKind::Call(then_call, [then_arg]) = then_expr.kind;
-            if let ExprKind::Path(ref then_call_qpath) = then_call.kind;
-            if is_lang_ctor(cx, then_call_qpath, OptionSome);
-            if let ExprKind::Path(ref qpath) = peel_blocks(els).kind;
-            if is_lang_ctor(cx, qpath, OptionNone);
-            if !stmts_contains_early_return(then_block.stmts);
-            then {
-                let cond_snip = snippet_with_macro_callsite(cx, cond.span, "[condition]");
-                let cond_snip = if matches!(cond.kind, ExprKind::Unary(_, _) | ExprKind::Binary(_, _, _)) {
-                    format!("({})", cond_snip)
-                } else {
-                    cond_snip.into_owned()
-                };
-                let arg_snip = snippet_with_macro_callsite(cx, then_arg.span, "");
-                let closure_body = if then_block.stmts.is_empty() {
-                    arg_snip.into_owned()
-                } else {
-                    format!("{{ /* snippet */ {} }}", arg_snip)
-                };
-                let help = format!(
-                    "consider using `bool::then` like: `{}.then(|| {})`",
-                    cond_snip,
-                    closure_body,
-                );
-                span_lint_and_help(
-                    cx,
-                    IF_THEN_SOME_ELSE_NONE,
-                    expr.span,
-                    "this could be simplified with `bool::then`",
-                    None,
-                    &help,
-                );
-            }
+        if let Some(higher::If { cond, then, r#else: Some(els) }) = higher::If::hir(expr)
+            && let ExprKind::Block(then_block, _) = then.kind
+            && let Some(then_expr) = then_block.expr
+            && let ExprKind::Call(then_call, [then_arg]) = then_expr.kind
+            && let ExprKind::Path(ref then_call_qpath) = then_call.kind
+            && is_lang_ctor(cx, then_call_qpath, OptionSome)
+            && let ExprKind::Path(ref qpath) = peel_blocks(els).kind
+            && is_lang_ctor(cx, qpath, OptionNone)
+            && !stmts_contains_early_return(then_block.stmts)
+        {
+            let cond_snip = snippet_with_macro_callsite(cx, cond.span, "[condition]");
+            let cond_snip = if matches!(cond.kind, ExprKind::Unary(_, _) | ExprKind::Binary(_, _, _)) {
+                format!("({})", cond_snip)
+            } else {
+                cond_snip.into_owned()
+            };
+            let arg_snip = snippet_with_macro_callsite(cx, then_arg.span, "");
+            let mut method_body = if then_block.stmts.is_empty() {
+                arg_snip.into_owned()
+            } else {
+                format!("{{ /* snippet */ {} }}", arg_snip)
+            };
+            let method_name = if switch_to_eager_eval(cx, expr) && meets_msrv(self.msrv, msrvs::BOOL_THEN_SOME) {
+                "then_some"
+            } else {
+                method_body.insert_str(0, "|| ");
+                "then"
+            };
+
+            let help = format!(
+                "consider using `bool::{}` like: `{}.{}({})`",
+                method_name, cond_snip, method_name, method_body,
+            );
+            span_lint_and_help(
+                cx,
+                IF_THEN_SOME_ELSE_NONE,
+                expr.span,
+                &format!("this could be simplified with `bool::{}`", method_name),
+                None,
+                &help,
+            );
         }
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/implicit_hasher.rs b/src/tools/clippy/clippy_lints/src/implicit_hasher.rs
index 4f9680f60fe8..804fdc2da088 100644
--- a/src/tools/clippy/clippy_lints/src/implicit_hasher.rs
+++ b/src/tools/clippy/clippy_lints/src/implicit_hasher.rs
@@ -112,7 +112,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitHasher {
             }
         }
 
-        if !cx.access_levels.is_exported(item.def_id) {
+        if !cx.access_levels.is_exported(item.def_id.def_id) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/implicit_return.rs b/src/tools/clippy/clippy_lints/src/implicit_return.rs
index a6610ade37e5..feec8ec2e23f 100644
--- a/src/tools/clippy/clippy_lints/src/implicit_return.rs
+++ b/src/tools/clippy/clippy_lints/src/implicit_return.rs
@@ -232,7 +232,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitReturn {
             return;
         }
 
-        let res_ty = cx.typeck_results().expr_ty(&body.value);
+        let res_ty = cx.typeck_results().expr_ty(body.value);
         if res_ty.is_unit() || res_ty.is_never() {
             return;
         }
@@ -243,7 +243,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitReturn {
                 None => return,
             }
         } else {
-            &body.value
+            body.value
         };
         lint_implicit_returns(cx, expr, expr.span.ctxt(), None);
     }
diff --git a/src/tools/clippy/clippy_lints/src/index_refutable_slice.rs b/src/tools/clippy/clippy_lints/src/index_refutable_slice.rs
index d0c6495e35a7..0dd7f5bf000d 100644
--- a/src/tools/clippy/clippy_lints/src/index_refutable_slice.rs
+++ b/src/tools/clippy/clippy_lints/src/index_refutable_slice.rs
@@ -95,12 +95,14 @@ fn find_slice_values(cx: &LateContext<'_>, pat: &hir::Pat<'_>) -> FxIndexMap<hir
     let mut removed_pat: FxHashSet<hir::HirId> = FxHashSet::default();
     let mut slices: FxIndexMap<hir::HirId, SliceLintInformation> = FxIndexMap::default();
     pat.walk_always(|pat| {
-        if let hir::PatKind::Binding(binding, value_hir_id, ident, sub_pat) = pat.kind {
-            // We'll just ignore mut and ref mut for simplicity sake right now
-            if let hir::BindingAnnotation::Mutable | hir::BindingAnnotation::RefMut = binding {
-                return;
-            }
-
+        // We'll just ignore mut and ref mut for simplicity sake right now
+        if let hir::PatKind::Binding(
+            hir::BindingAnnotation(by_ref, hir::Mutability::Not),
+            value_hir_id,
+            ident,
+            sub_pat,
+        ) = pat.kind
+        {
             // This block catches bindings with sub patterns. It would be hard to build a correct suggestion
             // for them and it's likely that the user knows what they are doing in such a case.
             if removed_pat.contains(&value_hir_id) {
@@ -116,7 +118,7 @@ fn find_slice_values(cx: &LateContext<'_>, pat: &hir::Pat<'_>) -> FxIndexMap<hir
             if let ty::Slice(inner_ty) | ty::Array(inner_ty, _) = bound_ty.peel_refs().kind() {
                 // The values need to use the `ref` keyword if they can't be copied.
                 // This will need to be adjusted if the lint want to support mutable access in the future
-                let src_is_ref = bound_ty.is_ref() && binding != hir::BindingAnnotation::Ref;
+                let src_is_ref = bound_ty.is_ref() && by_ref != hir::ByRef::Yes;
                 let needs_ref = !(src_is_ref || is_copy(cx, *inner_ty));
 
                 let slice_info = slices
diff --git a/src/tools/clippy/clippy_lints/src/infinite_iter.rs b/src/tools/clippy/clippy_lints/src/infinite_iter.rs
index 01c7eef4e04d..8c2c96fa105a 100644
--- a/src/tools/clippy/clippy_lints/src/infinite_iter.rs
+++ b/src/tools/clippy/clippy_lints/src/infinite_iter.rs
@@ -123,45 +123,45 @@ use self::Heuristic::{All, Always, Any, First};
 /// is an upper bound, e.g., some methods can return a possibly
 /// infinite iterator at worst, e.g., `take_while`.
 const HEURISTICS: [(&str, usize, Heuristic, Finiteness); 19] = [
-    ("zip", 2, All, Infinite),
-    ("chain", 2, Any, Infinite),
-    ("cycle", 1, Always, Infinite),
-    ("map", 2, First, Infinite),
-    ("by_ref", 1, First, Infinite),
-    ("cloned", 1, First, Infinite),
-    ("rev", 1, First, Infinite),
-    ("inspect", 1, First, Infinite),
-    ("enumerate", 1, First, Infinite),
-    ("peekable", 2, First, Infinite),
-    ("fuse", 1, First, Infinite),
-    ("skip", 2, First, Infinite),
-    ("skip_while", 1, First, Infinite),
-    ("filter", 2, First, Infinite),
-    ("filter_map", 2, First, Infinite),
-    ("flat_map", 2, First, Infinite),
-    ("unzip", 1, First, Infinite),
-    ("take_while", 2, First, MaybeInfinite),
-    ("scan", 3, First, MaybeInfinite),
+    ("zip", 1, All, Infinite),
+    ("chain", 1, Any, Infinite),
+    ("cycle", 0, Always, Infinite),
+    ("map", 1, First, Infinite),
+    ("by_ref", 0, First, Infinite),
+    ("cloned", 0, First, Infinite),
+    ("rev", 0, First, Infinite),
+    ("inspect", 0, First, Infinite),
+    ("enumerate", 0, First, Infinite),
+    ("peekable", 1, First, Infinite),
+    ("fuse", 0, First, Infinite),
+    ("skip", 1, First, Infinite),
+    ("skip_while", 0, First, Infinite),
+    ("filter", 1, First, Infinite),
+    ("filter_map", 1, First, Infinite),
+    ("flat_map", 1, First, Infinite),
+    ("unzip", 0, First, Infinite),
+    ("take_while", 1, First, MaybeInfinite),
+    ("scan", 2, First, MaybeInfinite),
 ];
 
 fn is_infinite(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
     match expr.kind {
-        ExprKind::MethodCall(method, args, _) => {
+        ExprKind::MethodCall(method, receiver, args, _) => {
             for &(name, len, heuristic, cap) in &HEURISTICS {
                 if method.ident.name.as_str() == name && args.len() == len {
                     return (match heuristic {
                         Always => Infinite,
-                        First => is_infinite(cx, &args[0]),
-                        Any => is_infinite(cx, &args[0]).or(is_infinite(cx, &args[1])),
-                        All => is_infinite(cx, &args[0]).and(is_infinite(cx, &args[1])),
+                        First => is_infinite(cx, receiver),
+                        Any => is_infinite(cx, receiver).or(is_infinite(cx, &args[0])),
+                        All => is_infinite(cx, receiver).and(is_infinite(cx, &args[0])),
                     })
                     .and(cap);
                 }
             }
-            if method.ident.name == sym!(flat_map) && args.len() == 2 {
-                if let ExprKind::Closure(&Closure { body, .. }) = args[1].kind {
+            if method.ident.name == sym!(flat_map) && args.len() == 1 {
+                if let ExprKind::Closure(&Closure { body, .. }) = args[0].kind {
                     let body = cx.tcx.hir().body(body);
-                    return is_infinite(cx, &body.value);
+                    return is_infinite(cx, body.value);
                 }
             }
             Finite
@@ -179,29 +179,29 @@ fn is_infinite(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
 /// the names and argument lengths of methods that *may* exhaust their
 /// iterators
 const POSSIBLY_COMPLETING_METHODS: [(&str, usize); 6] = [
-    ("find", 2),
-    ("rfind", 2),
-    ("position", 2),
-    ("rposition", 2),
-    ("any", 2),
-    ("all", 2),
+    ("find", 1),
+    ("rfind", 1),
+    ("position", 1),
+    ("rposition", 1),
+    ("any", 1),
+    ("all", 1),
 ];
 
 /// the names and argument lengths of methods that *always* exhaust
 /// their iterators
 const COMPLETING_METHODS: [(&str, usize); 12] = [
-    ("count", 1),
-    ("fold", 3),
-    ("for_each", 2),
-    ("partition", 2),
-    ("max", 1),
-    ("max_by", 2),
-    ("max_by_key", 2),
-    ("min", 1),
-    ("min_by", 2),
-    ("min_by_key", 2),
-    ("sum", 1),
-    ("product", 1),
+    ("count", 0),
+    ("fold", 2),
+    ("for_each", 1),
+    ("partition", 1),
+    ("max", 0),
+    ("max_by", 1),
+    ("max_by_key", 1),
+    ("min", 0),
+    ("min_by", 1),
+    ("min_by_key", 1),
+    ("sum", 0),
+    ("product", 0),
 ];
 
 /// the paths of types that are known to be infinitely allocating
@@ -218,26 +218,26 @@ const INFINITE_COLLECTORS: &[Symbol] = &[
 
 fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
     match expr.kind {
-        ExprKind::MethodCall(method, args, _) => {
+        ExprKind::MethodCall(method, receiver, args, _) => {
             for &(name, len) in &COMPLETING_METHODS {
                 if method.ident.name.as_str() == name && args.len() == len {
-                    return is_infinite(cx, &args[0]);
+                    return is_infinite(cx, receiver);
                 }
             }
             for &(name, len) in &POSSIBLY_COMPLETING_METHODS {
                 if method.ident.name.as_str() == name && args.len() == len {
-                    return MaybeInfinite.and(is_infinite(cx, &args[0]));
+                    return MaybeInfinite.and(is_infinite(cx, receiver));
                 }
             }
-            if method.ident.name == sym!(last) && args.len() == 1 {
+            if method.ident.name == sym!(last) && args.is_empty() {
                 let not_double_ended = cx
                     .tcx
                     .get_diagnostic_item(sym::DoubleEndedIterator)
                     .map_or(false, |id| {
-                        !implements_trait(cx, cx.typeck_results().expr_ty(&args[0]), id, &[])
+                        !implements_trait(cx, cx.typeck_results().expr_ty(receiver), id, &[])
                     });
                 if not_double_ended {
-                    return is_infinite(cx, &args[0]);
+                    return is_infinite(cx, receiver);
                 }
             } else if method.ident.name == sym!(collect) {
                 let ty = cx.typeck_results().expr_ty(expr);
@@ -245,7 +245,7 @@ fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
                     .iter()
                     .any(|diag_item| is_type_diagnostic_item(cx, ty, *diag_item))
                 {
-                    return is_infinite(cx, &args[0]);
+                    return is_infinite(cx, receiver);
                 }
             }
         },
diff --git a/src/tools/clippy/clippy_lints/src/inherent_to_string.rs b/src/tools/clippy/clippy_lints/src/inherent_to_string.rs
index 17d867aacb53..cb6c2ec0fb98 100644
--- a/src/tools/clippy/clippy_lints/src/inherent_to_string.rs
+++ b/src/tools/clippy/clippy_lints/src/inherent_to_string.rs
@@ -108,7 +108,7 @@ impl<'tcx> LateLintPass<'tcx> for InherentToString {
             if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id()), sym::String);
 
             // Filters instances of to_string which are required by a trait
-            if trait_ref_of_method(cx, impl_item.def_id).is_none();
+            if trait_ref_of_method(cx, impl_item.def_id.def_id).is_none();
 
             then {
                 show_lint(cx, impl_item);
diff --git a/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs b/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs
index b56d87c5348c..2027c23d328c 100644
--- a/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs
+++ b/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs
@@ -44,7 +44,7 @@ impl<'tcx> LateLintPass<'tcx> for IterNotReturningIterator {
         let name = item.ident.name.as_str();
         if matches!(name, "iter" | "iter_mut") {
             if let TraitItemKind::Fn(fn_sig, _) = &item.kind {
-                check_sig(cx, name, fn_sig, item.def_id);
+                check_sig(cx, name, fn_sig, item.def_id.def_id);
             }
         }
     }
@@ -58,7 +58,7 @@ impl<'tcx> LateLintPass<'tcx> for IterNotReturningIterator {
             )
         {
             if let ImplItemKind::Fn(fn_sig, _) = &item.kind {
-                check_sig(cx, name, fn_sig, item.def_id);
+                check_sig(cx, name, fn_sig, item.def_id.def_id);
             }
         }
     }
diff --git a/src/tools/clippy/clippy_lints/src/large_enum_variant.rs b/src/tools/clippy/clippy_lints/src/large_enum_variant.rs
index c58df126d624..eb13d0869c03 100644
--- a/src/tools/clippy/clippy_lints/src/large_enum_variant.rs
+++ b/src/tools/clippy/clippy_lints/src/large_enum_variant.rs
@@ -1,13 +1,12 @@
 //! lint when there is a large size difference between variants on an enum
 
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{diagnostics::span_lint_and_then, ty::is_copy};
+use clippy_utils::{diagnostics::span_lint_and_then, ty::approx_ty_size, ty::is_copy};
 use rustc_errors::Applicability;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::layout::LayoutOf;
-use rustc_middle::ty::{Adt, Ty};
+use rustc_middle::ty::{Adt, AdtDef, GenericArg, List, Ty};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
 
@@ -17,7 +16,7 @@ declare_clippy_lint! {
     /// `enum`s.
     ///
     /// ### Why is this bad?
-    /// Enum size is bounded by the largest variant. Having a
+    /// Enum size is bounded by the largest variant. Having one
     /// large variant can penalize the memory layout of that enum.
     ///
     /// ### Known problems
@@ -33,8 +32,9 @@ declare_clippy_lint! {
     /// use case it may be possible to store the large data in an auxiliary
     /// structure (e.g. Arena or ECS).
     ///
-    /// The lint will ignore generic types if the layout depends on the
-    /// generics, even if the size difference will be large anyway.
+    /// The lint will ignore the impact of generic types to the type layout by
+    /// assuming every type parameter is zero-sized. Depending on your use case,
+    /// this may lead to a false positive.
     ///
     /// ### Example
     /// ```rust
@@ -83,6 +83,38 @@ struct VariantInfo {
     fields_size: Vec<FieldInfo>,
 }
 
+fn variants_size<'tcx>(
+    cx: &LateContext<'tcx>,
+    adt: AdtDef<'tcx>,
+    subst: &'tcx List<GenericArg<'tcx>>,
+) -> Vec<VariantInfo> {
+    let mut variants_size = adt
+        .variants()
+        .iter()
+        .enumerate()
+        .map(|(i, variant)| {
+            let mut fields_size = variant
+                .fields
+                .iter()
+                .enumerate()
+                .map(|(i, f)| FieldInfo {
+                    ind: i,
+                    size: approx_ty_size(cx, f.ty(cx.tcx, subst)),
+                })
+                .collect::<Vec<_>>();
+            fields_size.sort_by(|a, b| (a.size.cmp(&b.size)));
+
+            VariantInfo {
+                ind: i,
+                size: fields_size.iter().map(|info| info.size).sum(),
+                fields_size,
+            }
+        })
+        .collect::<Vec<_>>();
+    variants_size.sort_by(|a, b| (b.size.cmp(&a.size)));
+    variants_size
+}
+
 impl_lint_pass!(LargeEnumVariant => [LARGE_ENUM_VARIANT]);
 
 impl<'tcx> LateLintPass<'tcx> for LargeEnumVariant {
@@ -92,36 +124,14 @@ impl<'tcx> LateLintPass<'tcx> for LargeEnumVariant {
         }
         if let ItemKind::Enum(ref def, _) = item.kind {
             let ty = cx.tcx.type_of(item.def_id);
-            let adt = ty.ty_adt_def().expect("already checked whether this is an enum");
+            let (adt, subst) = match ty.kind() {
+                Adt(adt, subst) => (adt, subst),
+                _ => panic!("already checked whether this is an enum"),
+            };
             if adt.variants().len() <= 1 {
                 return;
             }
-            let mut variants_size: Vec<VariantInfo> = Vec::new();
-            for (i, variant) in adt.variants().iter().enumerate() {
-                let mut fields_size = Vec::new();
-                for (i, f) in variant.fields.iter().enumerate() {
-                    let ty = cx.tcx.type_of(f.did);
-                    // don't lint variants which have a field of generic type.
-                    match cx.layout_of(ty) {
-                        Ok(l) => {
-                            let fsize = l.size.bytes();
-                            fields_size.push(FieldInfo { ind: i, size: fsize });
-                        },
-                        Err(_) => {
-                            return;
-                        },
-                    }
-                }
-                let size: u64 = fields_size.iter().map(|info| info.size).sum();
-
-                variants_size.push(VariantInfo {
-                    ind: i,
-                    size,
-                    fields_size,
-                });
-            }
-
-            variants_size.sort_by(|a, b| (b.size.cmp(&a.size)));
+            let variants_size = variants_size(cx, *adt, subst);
 
             let mut difference = variants_size[0].size - variants_size[1].size;
             if difference > self.maximum_size_difference_allowed {
@@ -129,20 +139,30 @@ impl<'tcx> LateLintPass<'tcx> for LargeEnumVariant {
                 span_lint_and_then(
                     cx,
                     LARGE_ENUM_VARIANT,
-                    def.variants[variants_size[0].ind].span,
+                    item.span,
                     "large size difference between variants",
                     |diag| {
                         diag.span_label(
-                            def.variants[variants_size[0].ind].span,
-                            &format!("this variant is {} bytes", variants_size[0].size),
+                            item.span,
+                            format!("the entire enum is at least {} bytes", approx_ty_size(cx, ty)),
                         );
-                        diag.span_note(
+                        diag.span_label(
+                            def.variants[variants_size[0].ind].span,
+                            format!("the largest variant contains at least {} bytes", variants_size[0].size),
+                        );
+                        diag.span_label(
                             def.variants[variants_size[1].ind].span,
-                            &format!("and the second-largest variant is {} bytes:", variants_size[1].size),
+                            &if variants_size[1].fields_size.is_empty() {
+                                "the second-largest variant carries no data at all".to_owned()
+                            } else {
+                                format!(
+                                    "the second-largest variant contains at least {} bytes",
+                                    variants_size[1].size
+                                )
+                            },
                         );
 
                         let fields = def.variants[variants_size[0].ind].data.fields();
-                        variants_size[0].fields_size.sort_by(|a, b| (a.size.cmp(&b.size)));
                         let mut applicability = Applicability::MaybeIncorrect;
                         if is_copy(cx, ty) || maybe_copy(cx, ty) {
                             diag.span_note(
diff --git a/src/tools/clippy/clippy_lints/src/large_stack_arrays.rs b/src/tools/clippy/clippy_lints/src/large_stack_arrays.rs
index 0acbd81aec34..5857d81ab1f2 100644
--- a/src/tools/clippy/clippy_lints/src/large_stack_arrays.rs
+++ b/src/tools/clippy/clippy_lints/src/large_stack_arrays.rs
@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::source::snippet;
-use if_chain::if_chain;
-use rustc_hir::{Expr, ExprKind};
+use rustc_hir::{Expr, ExprKind, Item, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::{self, ConstKind};
@@ -39,29 +38,28 @@ impl_lint_pass!(LargeStackArrays => [LARGE_STACK_ARRAYS]);
 
 impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if_chain! {
-            if let ExprKind::Repeat(_, _) = expr.kind;
-            if let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind();
-            if let ConstKind::Value(ty::ValTree::Leaf(element_count)) = cst.kind();
-            if let Ok(element_count) = element_count.try_to_machine_usize(cx.tcx);
-            if let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes());
-            if self.maximum_allowed_size < element_count * element_size;
-            then {
-                span_lint_and_help(
-                    cx,
-                    LARGE_STACK_ARRAYS,
-                    expr.span,
-                    &format!(
-                        "allocating a local array larger than {} bytes",
-                        self.maximum_allowed_size
-                    ),
-                    None,
-                    &format!(
-                        "consider allocating on the heap with `vec!{}.into_boxed_slice()`",
-                        snippet(cx, expr.span, "[...]")
-                    ),
-                );
-            }
-        }
+        if let ExprKind::Repeat(_, _) = expr.kind
+          && let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind()
+          && let ConstKind::Value(ty::ValTree::Leaf(element_count)) = cst.kind()
+          && let Ok(element_count) = element_count.try_to_machine_usize(cx.tcx)
+          && let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes())
+          && !cx.tcx.hir().parent_iter(expr.hir_id)
+              .any(|(_, node)| matches!(node, Node::Item(Item { kind: ItemKind::Static(..), .. })))
+          && self.maximum_allowed_size < element_count * element_size {
+              span_lint_and_help(
+                  cx,
+                  LARGE_STACK_ARRAYS,
+                  expr.span,
+                  &format!(
+                      "allocating a local array larger than {} bytes",
+                      self.maximum_allowed_size
+                  ),
+                  None,
+                  &format!(
+                      "consider allocating on the heap with `vec!{}.into_boxed_slice()`",
+                      snippet(cx, expr.span, "[...]")
+                  ),
+              );
+          }
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/len_zero.rs b/src/tools/clippy/clippy_lints/src/len_zero.rs
index 246f5aad8fba..7d15dd4cb216 100644
--- a/src/tools/clippy/clippy_lints/src/len_zero.rs
+++ b/src/tools/clippy/clippy_lints/src/len_zero.rs
@@ -134,7 +134,7 @@ impl<'tcx> LateLintPass<'tcx> for LenZero {
             if item.ident.name == sym::len;
             if let ImplItemKind::Fn(sig, _) = &item.kind;
             if sig.decl.implicit_self.has_implicit_self();
-            if cx.access_levels.is_exported(item.def_id);
+            if cx.access_levels.is_exported(item.def_id.def_id);
             if matches!(sig.decl.output, FnRetTy::Return(_));
             if let Some(imp) = get_parent_as_impl(cx.tcx, item.hir_id());
             if imp.of_trait.is_none();
@@ -210,7 +210,7 @@ fn check_trait_items(cx: &LateContext<'_>, visited_trait: &Item<'_>, trait_items
         }
     }
 
-    if cx.access_levels.is_exported(visited_trait.def_id) && trait_items.iter().any(|i| is_named_self(cx, i, sym::len))
+    if cx.access_levels.is_exported(visited_trait.def_id.def_id) && trait_items.iter().any(|i| is_named_self(cx, i, sym::len))
     {
         let mut current_and_super_traits = DefIdSet::default();
         fill_trait_set(visited_trait.def_id.to_def_id(), &mut current_and_super_traits, cx);
@@ -370,7 +370,8 @@ fn check_for_is_empty<'tcx>(
 }
 
 fn check_cmp(cx: &LateContext<'_>, span: Span, method: &Expr<'_>, lit: &Expr<'_>, op: &str, compare_to: u32) {
-    if let (&ExprKind::MethodCall(method_path, args, _), &ExprKind::Lit(ref lit)) = (&method.kind, &lit.kind) {
+    if let (&ExprKind::MethodCall(method_path, receiver, args, _), &ExprKind::Lit(ref lit)) = (&method.kind, &lit.kind)
+    {
         // check if we are in an is_empty() method
         if let Some(name) = get_item_name(cx, method) {
             if name.as_str() == "is_empty" {
@@ -378,16 +379,28 @@ fn check_cmp(cx: &LateContext<'_>, span: Span, method: &Expr<'_>, lit: &Expr<'_>
             }
         }
 
-        check_len(cx, span, method_path.ident.name, args, &lit.node, op, compare_to);
+        check_len(
+            cx,
+            span,
+            method_path.ident.name,
+            receiver,
+            args,
+            &lit.node,
+            op,
+            compare_to,
+        );
     } else {
         check_empty_expr(cx, span, method, lit, op);
     }
 }
 
+// FIXME(flip1995): Figure out how to reduce the number of arguments
+#[allow(clippy::too_many_arguments)]
 fn check_len(
     cx: &LateContext<'_>,
     span: Span,
     method_name: Symbol,
+    receiver: &Expr<'_>,
     args: &[Expr<'_>],
     lit: &LitKind,
     op: &str,
@@ -399,7 +412,7 @@ fn check_len(
             return;
         }
 
-        if method_name == sym::len && args.len() == 1 && has_is_empty(cx, &args[0]) {
+        if method_name == sym::len && args.is_empty() && has_is_empty(cx, receiver) {
             let mut applicability = Applicability::MachineApplicable;
             span_lint_and_sugg(
                 cx,
@@ -410,7 +423,7 @@ fn check_len(
                 format!(
                     "{}{}.is_empty()",
                     op,
-                    snippet_with_applicability(cx, args[0].span, "_", &mut applicability)
+                    snippet_with_applicability(cx, receiver.span, "_", &mut applicability)
                 ),
                 applicability,
             );
diff --git a/src/tools/clippy/clippy_lints/src/let_if_seq.rs b/src/tools/clippy/clippy_lints/src/let_if_seq.rs
index 56bbbbbc819e..10fc0f4018ef 100644
--- a/src/tools/clippy/clippy_lints/src/let_if_seq.rs
+++ b/src/tools/clippy/clippy_lints/src/let_if_seq.rs
@@ -4,7 +4,7 @@ use clippy_utils::{path_to_local_id, visitors::is_local_used};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
-use rustc_hir::BindingAnnotation;
+use rustc_hir::{BindingAnnotation, Mutability};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
@@ -98,7 +98,7 @@ impl<'tcx> LateLintPass<'tcx> for LetIfSeq {
                     };
 
                     let mutability = match mode {
-                        BindingAnnotation::RefMut | BindingAnnotation::Mutable => "<mut> ",
+                        BindingAnnotation(_, Mutability::Mut) => "<mut> ",
                         _ => "",
                     };
 
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_all.rs b/src/tools/clippy/clippy_lints/src/lib.register_all.rs
index 01082cc8eeb6..8718d5fa1da0 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_all.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_all.rs
@@ -17,15 +17,16 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(await_holding_invalid::AWAIT_HOLDING_REFCELL_REF),
     LintId::of(blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS),
     LintId::of(bool_assert_comparison::BOOL_ASSERT_COMPARISON),
+    LintId::of(bool_to_int_with_if::BOOL_TO_INT_WITH_IF),
     LintId::of(booleans::NONMINIMAL_BOOL),
     LintId::of(booleans::OVERLY_COMPLEX_BOOL_EXPR),
     LintId::of(borrow_deref_ref::BORROW_DEREF_REF),
-    LintId::of(bytes_count_to_len::BYTES_COUNT_TO_LEN),
     LintId::of(casts::CAST_ABS_TO_UNSIGNED),
     LintId::of(casts::CAST_ENUM_CONSTRUCTOR),
     LintId::of(casts::CAST_ENUM_TRUNCATION),
     LintId::of(casts::CAST_REF_TO_MUT),
     LintId::of(casts::CAST_SLICE_DIFFERENT_SIZES),
+    LintId::of(casts::CAST_SLICE_FROM_RAW_PARTS),
     LintId::of(casts::CHAR_LIT_AS_U8),
     LintId::of(casts::FN_TO_NUMERIC_CAST),
     LintId::of(casts::FN_TO_NUMERIC_CAST_WITH_TRUNCATION),
@@ -80,9 +81,9 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(functions::DOUBLE_MUST_USE),
     LintId::of(functions::MUST_USE_UNIT),
     LintId::of(functions::NOT_UNSAFE_PTR_ARG_DEREF),
+    LintId::of(functions::RESULT_LARGE_ERR),
     LintId::of(functions::RESULT_UNIT_ERR),
     LintId::of(functions::TOO_MANY_ARGUMENTS),
-    LintId::of(get_first::GET_FIRST),
     LintId::of(if_let_mutex::IF_LET_MUTEX),
     LintId::of(indexing_slicing::OUT_OF_BOUNDS_INDEXING),
     LintId::of(infinite_iter::INFINITE_ITER),
@@ -128,7 +129,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(manual_rem_euclid::MANUAL_REM_EUCLID),
     LintId::of(manual_retain::MANUAL_RETAIN),
     LintId::of(manual_strip::MANUAL_STRIP),
-    LintId::of(map_clone::MAP_CLONE),
     LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN),
     LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN),
     LintId::of(match_result_ok::MATCH_RESULT_OK),
@@ -150,17 +150,20 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(mem_replace::MEM_REPLACE_WITH_DEFAULT),
     LintId::of(mem_replace::MEM_REPLACE_WITH_UNINIT),
     LintId::of(methods::BIND_INSTEAD_OF_MAP),
+    LintId::of(methods::BYTES_COUNT_TO_LEN),
     LintId::of(methods::BYTES_NTH),
     LintId::of(methods::CHARS_LAST_CMP),
     LintId::of(methods::CHARS_NEXT_CMP),
     LintId::of(methods::CLONE_DOUBLE_REF),
     LintId::of(methods::CLONE_ON_COPY),
+    LintId::of(methods::COLLAPSIBLE_STR_REPLACE),
     LintId::of(methods::ERR_EXPECT),
     LintId::of(methods::EXPECT_FUN_CALL),
     LintId::of(methods::EXTEND_WITH_DRAIN),
     LintId::of(methods::FILTER_MAP_IDENTITY),
     LintId::of(methods::FILTER_NEXT),
     LintId::of(methods::FLAT_MAP_IDENTITY),
+    LintId::of(methods::GET_FIRST),
     LintId::of(methods::GET_LAST_WITH_LEN),
     LintId::of(methods::INSPECT_FOR_EACH),
     LintId::of(methods::INTO_ITER_ON_REF),
@@ -168,6 +171,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(methods::ITERATOR_STEP_BY_ZERO),
     LintId::of(methods::ITER_CLONED_COLLECT),
     LintId::of(methods::ITER_COUNT),
+    LintId::of(methods::ITER_KV_MAP),
     LintId::of(methods::ITER_NEXT_SLICE),
     LintId::of(methods::ITER_NTH),
     LintId::of(methods::ITER_NTH_ZERO),
@@ -178,13 +182,16 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(methods::MANUAL_SATURATING_ARITHMETIC),
     LintId::of(methods::MANUAL_SPLIT_ONCE),
     LintId::of(methods::MANUAL_STR_REPEAT),
+    LintId::of(methods::MAP_CLONE),
     LintId::of(methods::MAP_COLLECT_RESULT_UNIT),
     LintId::of(methods::MAP_FLATTEN),
     LintId::of(methods::MAP_IDENTITY),
+    LintId::of(methods::MUT_MUTEX_LOCK),
     LintId::of(methods::NEEDLESS_OPTION_AS_DEREF),
     LintId::of(methods::NEEDLESS_OPTION_TAKE),
     LintId::of(methods::NEEDLESS_SPLITN),
     LintId::of(methods::NEW_RET_NO_SELF),
+    LintId::of(methods::NONSENSICAL_OPEN_OPTIONS),
     LintId::of(methods::NO_EFFECT_REPLACE),
     LintId::of(methods::OBFUSCATED_IF_ELSE),
     LintId::of(methods::OK_EXPECT),
@@ -193,6 +200,8 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(methods::OPTION_MAP_OR_NONE),
     LintId::of(methods::OR_FUN_CALL),
     LintId::of(methods::OR_THEN_UNWRAP),
+    LintId::of(methods::RANGE_ZIP_WITH_LEN),
+    LintId::of(methods::REPEAT_ONCE),
     LintId::of(methods::RESULT_MAP_OR_INTO_OPTION),
     LintId::of(methods::SEARCH_IS_SOME),
     LintId::of(methods::SHOULD_IMPLEMENT_TRAIT),
@@ -202,14 +211,18 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(methods::STRING_EXTEND_CHARS),
     LintId::of(methods::SUSPICIOUS_MAP),
     LintId::of(methods::SUSPICIOUS_SPLITN),
+    LintId::of(methods::SUSPICIOUS_TO_OWNED),
     LintId::of(methods::UNINIT_ASSUMED_INIT),
+    LintId::of(methods::UNIT_HASH),
     LintId::of(methods::UNNECESSARY_FILTER_MAP),
     LintId::of(methods::UNNECESSARY_FIND_MAP),
     LintId::of(methods::UNNECESSARY_FOLD),
     LintId::of(methods::UNNECESSARY_LAZY_EVALUATIONS),
+    LintId::of(methods::UNNECESSARY_SORT_BY),
     LintId::of(methods::UNNECESSARY_TO_OWNED),
     LintId::of(methods::UNWRAP_OR_ELSE_DEFAULT),
     LintId::of(methods::USELESS_ASREF),
+    LintId::of(methods::VEC_RESIZE_TO_ZERO),
     LintId::of(methods::WRONG_SELF_CONVENTION),
     LintId::of(methods::ZST_OFFSET),
     LintId::of(minmax::MIN_MAX),
@@ -224,8 +237,8 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(misc_early::UNNEEDED_WILDCARD_PATTERN),
     LintId::of(misc_early::ZERO_PREFIXED_LITERAL),
     LintId::of(mixed_read_write_in_expression::DIVERGING_SUB_EXPRESSION),
+    LintId::of(multi_assignments::MULTI_ASSIGNMENTS),
     LintId::of(mut_key::MUTABLE_KEY_TYPE),
-    LintId::of(mut_mutex_lock::MUT_MUTEX_LOCK),
     LintId::of(mut_reference::UNNECESSARY_MUT_PASSED),
     LintId::of(needless_arbitrary_self_type::NEEDLESS_ARBITRARY_SELF_TYPE),
     LintId::of(needless_bool::BOOL_COMPARISON),
@@ -245,7 +258,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(non_expressive_names::JUST_UNDERSCORES_AND_DIGITS),
     LintId::of(non_octal_unix_permissions::NON_OCTAL_UNIX_PERMISSIONS),
     LintId::of(octal_escapes::OCTAL_ESCAPES),
-    LintId::of(open_options::NONSENSICAL_OPEN_OPTIONS),
+    LintId::of(only_used_in_recursion::ONLY_USED_IN_RECURSION),
     LintId::of(operators::ABSURD_EXTREME_COMPARISONS),
     LintId::of(operators::ASSIGN_OP_PATTERN),
     LintId::of(operators::BAD_BIT_MASK),
@@ -275,7 +288,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(ptr_offset_with_cast::PTR_OFFSET_WITH_CAST),
     LintId::of(question_mark::QUESTION_MARK),
     LintId::of(ranges::MANUAL_RANGE_CONTAINS),
-    LintId::of(ranges::RANGE_ZIP_WITH_LEN),
     LintId::of(ranges::REVERSED_EMPTY_RANGES),
     LintId::of(rc_clone_in_vec_init::RC_CLONE_IN_VEC_INIT),
     LintId::of(read_zero_byte_vec::READ_ZERO_BYTE_VEC),
@@ -286,7 +298,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(redundant_static_lifetimes::REDUNDANT_STATIC_LIFETIMES),
     LintId::of(reference::DEREF_ADDROF),
     LintId::of(regex::INVALID_REGEX),
-    LintId::of(repeat_once::REPEAT_ONCE),
     LintId::of(returns::LET_AND_RETURN),
     LintId::of(returns::NEEDLESS_RETURN),
     LintId::of(self_named_constructors::SELF_NAMED_CONSTRUCTORS),
@@ -314,10 +325,10 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(transmute::TRANSMUTE_INT_TO_FLOAT),
     LintId::of(transmute::TRANSMUTE_NUM_TO_BYTES),
     LintId::of(transmute::TRANSMUTE_PTR_TO_REF),
+    LintId::of(transmute::TRANSMUTING_NULL),
     LintId::of(transmute::UNSOUND_COLLECTION_TRANSMUTE),
     LintId::of(transmute::USELESS_TRANSMUTE),
     LintId::of(transmute::WRONG_TRANSMUTE),
-    LintId::of(transmuting_null::TRANSMUTING_NULL),
     LintId::of(types::BORROWED_BOX),
     LintId::of(types::BOX_COLLECTION),
     LintId::of(types::REDUNDANT_ALLOCATION),
@@ -325,7 +336,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(types::VEC_BOX),
     LintId::of(unicode::INVISIBLE_CHARACTERS),
     LintId::of(uninit_vec::UNINIT_VEC),
-    LintId::of(unit_hash::UNIT_HASH),
     LintId::of(unit_return_expecting_ord::UNIT_RETURN_EXPECTING_ORD),
     LintId::of(unit_types::LET_UNIT_VALUE),
     LintId::of(unit_types::UNIT_ARG),
@@ -333,7 +343,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(unnamed_address::FN_ADDRESS_COMPARISONS),
     LintId::of(unnamed_address::VTABLE_ADDRESS_COMPARISONS),
     LintId::of(unnecessary_owned_empty_strings::UNNECESSARY_OWNED_EMPTY_STRINGS),
-    LintId::of(unnecessary_sort_by::UNNECESSARY_SORT_BY),
     LintId::of(unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME),
     LintId::of(unused_io_amount::UNUSED_IO_AMOUNT),
     LintId::of(unused_unit::UNUSED_UNIT),
@@ -343,7 +352,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(useless_conversion::USELESS_CONVERSION),
     LintId::of(vec::USELESS_VEC),
     LintId::of(vec_init_then_push::VEC_INIT_THEN_PUSH),
-    LintId::of(vec_resize_to_zero::VEC_RESIZE_TO_ZERO),
     LintId::of(write::PRINTLN_EMPTY_STRING),
     LintId::of(write::PRINT_LITERAL),
     LintId::of(write::PRINT_WITH_NEWLINE),
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_complexity.rs b/src/tools/clippy/clippy_lints/src/lib.register_complexity.rs
index 3784d3c68dce..185189a6af5b 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_complexity.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_complexity.rs
@@ -6,7 +6,6 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(attrs::DEPRECATED_CFG_ATTR),
     LintId::of(booleans::NONMINIMAL_BOOL),
     LintId::of(borrow_deref_ref::BORROW_DEREF_REF),
-    LintId::of(bytes_count_to_len::BYTES_COUNT_TO_LEN),
     LintId::of(casts::CHAR_LIT_AS_U8),
     LintId::of(casts::UNNECESSARY_CAST),
     LintId::of(dereference::EXPLICIT_AUTO_DEREF),
@@ -33,6 +32,7 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(matches::NEEDLESS_MATCH),
     LintId::of(matches::WILDCARD_IN_OR_PATTERNS),
     LintId::of(methods::BIND_INSTEAD_OF_MAP),
+    LintId::of(methods::BYTES_COUNT_TO_LEN),
     LintId::of(methods::CLONE_ON_COPY),
     LintId::of(methods::FILTER_MAP_IDENTITY),
     LintId::of(methods::FILTER_NEXT),
@@ -40,6 +40,7 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(methods::GET_LAST_WITH_LEN),
     LintId::of(methods::INSPECT_FOR_EACH),
     LintId::of(methods::ITER_COUNT),
+    LintId::of(methods::ITER_KV_MAP),
     LintId::of(methods::MANUAL_FILTER_MAP),
     LintId::of(methods::MANUAL_FIND_MAP),
     LintId::of(methods::MANUAL_SPLIT_ONCE),
@@ -51,10 +52,13 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(methods::OPTION_AS_REF_DEREF),
     LintId::of(methods::OPTION_FILTER_MAP),
     LintId::of(methods::OR_THEN_UNWRAP),
+    LintId::of(methods::RANGE_ZIP_WITH_LEN),
+    LintId::of(methods::REPEAT_ONCE),
     LintId::of(methods::SEARCH_IS_SOME),
     LintId::of(methods::SKIP_WHILE_NEXT),
     LintId::of(methods::UNNECESSARY_FILTER_MAP),
     LintId::of(methods::UNNECESSARY_FIND_MAP),
+    LintId::of(methods::UNNECESSARY_SORT_BY),
     LintId::of(methods::USELESS_ASREF),
     LintId::of(misc::SHORT_CIRCUIT_STATEMENT),
     LintId::of(misc_early::UNNEEDED_WILDCARD_PATTERN),
@@ -69,6 +73,7 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(neg_cmp_op_on_partial_ord::NEG_CMP_OP_ON_PARTIAL_ORD),
     LintId::of(no_effect::NO_EFFECT),
     LintId::of(no_effect::UNNECESSARY_OPERATION),
+    LintId::of(only_used_in_recursion::ONLY_USED_IN_RECURSION),
     LintId::of(operators::DOUBLE_COMPARISONS),
     LintId::of(operators::DURATION_SUBSEC),
     LintId::of(operators::IDENTITY_OP),
@@ -76,11 +81,9 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(partialeq_ne_impl::PARTIALEQ_NE_IMPL),
     LintId::of(precedence::PRECEDENCE),
     LintId::of(ptr_offset_with_cast::PTR_OFFSET_WITH_CAST),
-    LintId::of(ranges::RANGE_ZIP_WITH_LEN),
     LintId::of(redundant_closure_call::REDUNDANT_CLOSURE_CALL),
     LintId::of(redundant_slicing::REDUNDANT_SLICING),
     LintId::of(reference::DEREF_ADDROF),
-    LintId::of(repeat_once::REPEAT_ONCE),
     LintId::of(strings::STRING_FROM_UTF8_AS_BYTES),
     LintId::of(strlen_on_c_strings::STRLEN_ON_C_STRINGS),
     LintId::of(swap::MANUAL_SWAP),
@@ -99,7 +102,6 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(types::TYPE_COMPLEXITY),
     LintId::of(types::VEC_BOX),
     LintId::of(unit_types::UNIT_ARG),
-    LintId::of(unnecessary_sort_by::UNNECESSARY_SORT_BY),
     LintId::of(unwrap::UNNECESSARY_UNWRAP),
     LintId::of(useless_conversion::USELESS_CONVERSION),
     LintId::of(zero_div_zero::ZERO_DIVIDED_BY_ZERO),
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_correctness.rs b/src/tools/clippy/clippy_lints/src/lib.register_correctness.rs
index 006275d1383f..bb94037ec2e7 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_correctness.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_correctness.rs
@@ -39,12 +39,14 @@ store.register_group(true, "clippy::correctness", Some("clippy_correctness"), ve
     LintId::of(mem_replace::MEM_REPLACE_WITH_UNINIT),
     LintId::of(methods::CLONE_DOUBLE_REF),
     LintId::of(methods::ITERATOR_STEP_BY_ZERO),
+    LintId::of(methods::NONSENSICAL_OPEN_OPTIONS),
     LintId::of(methods::SUSPICIOUS_SPLITN),
     LintId::of(methods::UNINIT_ASSUMED_INIT),
+    LintId::of(methods::UNIT_HASH),
+    LintId::of(methods::VEC_RESIZE_TO_ZERO),
     LintId::of(methods::ZST_OFFSET),
     LintId::of(minmax::MIN_MAX),
     LintId::of(non_octal_unix_permissions::NON_OCTAL_UNIX_PERMISSIONS),
-    LintId::of(open_options::NONSENSICAL_OPEN_OPTIONS),
     LintId::of(operators::ABSURD_EXTREME_COMPARISONS),
     LintId::of(operators::BAD_BIT_MASK),
     LintId::of(operators::CMP_NAN),
@@ -62,17 +64,15 @@ store.register_group(true, "clippy::correctness", Some("clippy_correctness"), ve
     LintId::of(serde_api::SERDE_API_MISUSE),
     LintId::of(size_of_in_element_count::SIZE_OF_IN_ELEMENT_COUNT),
     LintId::of(swap::ALMOST_SWAPPED),
+    LintId::of(transmute::TRANSMUTING_NULL),
     LintId::of(transmute::UNSOUND_COLLECTION_TRANSMUTE),
     LintId::of(transmute::WRONG_TRANSMUTE),
-    LintId::of(transmuting_null::TRANSMUTING_NULL),
     LintId::of(unicode::INVISIBLE_CHARACTERS),
     LintId::of(uninit_vec::UNINIT_VEC),
-    LintId::of(unit_hash::UNIT_HASH),
     LintId::of(unit_return_expecting_ord::UNIT_RETURN_EXPECTING_ORD),
     LintId::of(unit_types::UNIT_CMP),
     LintId::of(unnamed_address::FN_ADDRESS_COMPARISONS),
     LintId::of(unnamed_address::VTABLE_ADDRESS_COMPARISONS),
     LintId::of(unused_io_amount::UNUSED_IO_AMOUNT),
     LintId::of(unwrap::PANICKING_UNWRAP),
-    LintId::of(vec_resize_to_zero::VEC_RESIZE_TO_ZERO),
 ])
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_lints.rs b/src/tools/clippy/clippy_lints/src/lib.register_lints.rs
index c540573b8022..02fcc8de5072 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_lints.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_lints.rs
@@ -38,7 +38,6 @@ store.register_lints(&[
     almost_complete_letter_range::ALMOST_COMPLETE_LETTER_RANGE,
     approx_const::APPROX_CONSTANT,
     as_conversions::AS_CONVERSIONS,
-    as_underscore::AS_UNDERSCORE,
     asm_syntax::INLINE_ASM_X86_ATT_SYNTAX,
     asm_syntax::INLINE_ASM_X86_INTEL_SYNTAX,
     assertions_on_constants::ASSERTIONS_ON_CONSTANTS,
@@ -57,18 +56,17 @@ store.register_lints(&[
     await_holding_invalid::AWAIT_HOLDING_REFCELL_REF,
     blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS,
     bool_assert_comparison::BOOL_ASSERT_COMPARISON,
+    bool_to_int_with_if::BOOL_TO_INT_WITH_IF,
     booleans::NONMINIMAL_BOOL,
     booleans::OVERLY_COMPLEX_BOOL_EXPR,
-    borrow_as_ptr::BORROW_AS_PTR,
     borrow_deref_ref::BORROW_DEREF_REF,
-    bytecount::NAIVE_BYTECOUNT,
-    bytes_count_to_len::BYTES_COUNT_TO_LEN,
     cargo::CARGO_COMMON_METADATA,
     cargo::MULTIPLE_CRATE_VERSIONS,
     cargo::NEGATIVE_FEATURE_NAMES,
     cargo::REDUNDANT_FEATURE_NAMES,
     cargo::WILDCARD_DEPENDENCIES,
-    case_sensitive_file_extension_comparisons::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
+    casts::AS_UNDERSCORE,
+    casts::BORROW_AS_PTR,
     casts::CAST_ABS_TO_UNSIGNED,
     casts::CAST_ENUM_CONSTRUCTOR,
     casts::CAST_ENUM_TRUNCATION,
@@ -80,6 +78,7 @@ store.register_lints(&[
     casts::CAST_REF_TO_MUT,
     casts::CAST_SIGN_LOSS,
     casts::CAST_SLICE_DIFFERENT_SIZES,
+    casts::CAST_SLICE_FROM_RAW_PARTS,
     casts::CHAR_LIT_AS_U8,
     casts::FN_TO_NUMERIC_CAST,
     casts::FN_TO_NUMERIC_CAST_ANY,
@@ -173,11 +172,11 @@ store.register_lints(&[
     functions::MUST_USE_CANDIDATE,
     functions::MUST_USE_UNIT,
     functions::NOT_UNSAFE_PTR_ARG_DEREF,
+    functions::RESULT_LARGE_ERR,
     functions::RESULT_UNIT_ERR,
     functions::TOO_MANY_ARGUMENTS,
     functions::TOO_MANY_LINES,
     future_not_send::FUTURE_NOT_SEND,
-    get_first::GET_FIRST,
     if_let_mutex::IF_LET_MUTEX,
     if_not_else::IF_NOT_ELSE,
     if_then_some_else_none::IF_THEN_SOME_ELSE_NONE,
@@ -246,12 +245,10 @@ store.register_lints(&[
     manual_bits::MANUAL_BITS,
     manual_instant_elapsed::MANUAL_INSTANT_ELAPSED,
     manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE,
-    manual_ok_or::MANUAL_OK_OR,
     manual_rem_euclid::MANUAL_REM_EUCLID,
     manual_retain::MANUAL_RETAIN,
+    manual_string_new::MANUAL_STRING_NEW,
     manual_strip::MANUAL_STRIP,
-    map_clone::MAP_CLONE,
-    map_err_ignore::MAP_ERR_IGNORE,
     map_unit_fn::OPTION_MAP_UNIT_FN,
     map_unit_fn::RESULT_MAP_UNIT_FN,
     match_result_ok::MATCH_RESULT_OK,
@@ -284,13 +281,16 @@ store.register_lints(&[
     mem_replace::MEM_REPLACE_WITH_DEFAULT,
     mem_replace::MEM_REPLACE_WITH_UNINIT,
     methods::BIND_INSTEAD_OF_MAP,
+    methods::BYTES_COUNT_TO_LEN,
     methods::BYTES_NTH,
+    methods::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
     methods::CHARS_LAST_CMP,
     methods::CHARS_NEXT_CMP,
     methods::CLONED_INSTEAD_OF_COPIED,
     methods::CLONE_DOUBLE_REF,
     methods::CLONE_ON_COPY,
     methods::CLONE_ON_REF_PTR,
+    methods::COLLAPSIBLE_STR_REPLACE,
     methods::ERR_EXPECT,
     methods::EXPECT_FUN_CALL,
     methods::EXPECT_USED,
@@ -302,6 +302,7 @@ store.register_lints(&[
     methods::FLAT_MAP_IDENTITY,
     methods::FLAT_MAP_OPTION,
     methods::FROM_ITER_INSTEAD_OF_COLLECT,
+    methods::GET_FIRST,
     methods::GET_LAST_WITH_LEN,
     methods::GET_UNWRAP,
     methods::IMPLICIT_CLONE,
@@ -312,25 +313,34 @@ store.register_lints(&[
     methods::ITERATOR_STEP_BY_ZERO,
     methods::ITER_CLONED_COLLECT,
     methods::ITER_COUNT,
+    methods::ITER_KV_MAP,
     methods::ITER_NEXT_SLICE,
     methods::ITER_NTH,
     methods::ITER_NTH_ZERO,
+    methods::ITER_ON_EMPTY_COLLECTIONS,
+    methods::ITER_ON_SINGLE_ITEMS,
     methods::ITER_OVEREAGER_CLONED,
     methods::ITER_SKIP_NEXT,
     methods::ITER_WITH_DRAIN,
     methods::MANUAL_FILTER_MAP,
     methods::MANUAL_FIND_MAP,
+    methods::MANUAL_OK_OR,
     methods::MANUAL_SATURATING_ARITHMETIC,
     methods::MANUAL_SPLIT_ONCE,
     methods::MANUAL_STR_REPEAT,
+    methods::MAP_CLONE,
     methods::MAP_COLLECT_RESULT_UNIT,
+    methods::MAP_ERR_IGNORE,
     methods::MAP_FLATTEN,
     methods::MAP_IDENTITY,
     methods::MAP_UNWRAP_OR,
+    methods::MUT_MUTEX_LOCK,
+    methods::NAIVE_BYTECOUNT,
     methods::NEEDLESS_OPTION_AS_DEREF,
     methods::NEEDLESS_OPTION_TAKE,
     methods::NEEDLESS_SPLITN,
     methods::NEW_RET_NO_SELF,
+    methods::NONSENSICAL_OPEN_OPTIONS,
     methods::NO_EFFECT_REPLACE,
     methods::OBFUSCATED_IF_ELSE,
     methods::OK_EXPECT,
@@ -339,25 +349,34 @@ store.register_lints(&[
     methods::OPTION_MAP_OR_NONE,
     methods::OR_FUN_CALL,
     methods::OR_THEN_UNWRAP,
+    methods::PATH_BUF_PUSH_OVERWRITE,
+    methods::RANGE_ZIP_WITH_LEN,
+    methods::REPEAT_ONCE,
     methods::RESULT_MAP_OR_INTO_OPTION,
     methods::SEARCH_IS_SOME,
     methods::SHOULD_IMPLEMENT_TRAIT,
     methods::SINGLE_CHAR_ADD_STR,
     methods::SINGLE_CHAR_PATTERN,
     methods::SKIP_WHILE_NEXT,
+    methods::STABLE_SORT_PRIMITIVE,
     methods::STRING_EXTEND_CHARS,
     methods::SUSPICIOUS_MAP,
     methods::SUSPICIOUS_SPLITN,
+    methods::SUSPICIOUS_TO_OWNED,
     methods::UNINIT_ASSUMED_INIT,
+    methods::UNIT_HASH,
     methods::UNNECESSARY_FILTER_MAP,
     methods::UNNECESSARY_FIND_MAP,
     methods::UNNECESSARY_FOLD,
     methods::UNNECESSARY_JOIN,
     methods::UNNECESSARY_LAZY_EVALUATIONS,
+    methods::UNNECESSARY_SORT_BY,
     methods::UNNECESSARY_TO_OWNED,
     methods::UNWRAP_OR_ELSE_DEFAULT,
     methods::UNWRAP_USED,
     methods::USELESS_ASREF,
+    methods::VEC_RESIZE_TO_ZERO,
+    methods::VERBOSE_FILE_READS,
     methods::WRONG_SELF_CONVENTION,
     methods::ZST_OFFSET,
     minmax::MIN_MAX,
@@ -384,9 +403,9 @@ store.register_lints(&[
     mixed_read_write_in_expression::MIXED_READ_WRITE_IN_EXPRESSION,
     module_style::MOD_MODULE_FILES,
     module_style::SELF_NAMED_MODULE_FILES,
+    multi_assignments::MULTI_ASSIGNMENTS,
     mut_key::MUTABLE_KEY_TYPE,
     mut_mut::MUT_MUT,
-    mut_mutex_lock::MUT_MUTEX_LOCK,
     mut_reference::UNNECESSARY_MUT_PASSED,
     mutable_debug_assertion::DEBUG_ASSERT_WITH_MUT_CALL,
     mutex_atomic::MUTEX_ATOMIC,
@@ -418,9 +437,8 @@ store.register_lints(&[
     nonstandard_macro_braces::NONSTANDARD_MACRO_BRACES,
     octal_escapes::OCTAL_ESCAPES,
     only_used_in_recursion::ONLY_USED_IN_RECURSION,
-    open_options::NONSENSICAL_OPEN_OPTIONS,
     operators::ABSURD_EXTREME_COMPARISONS,
-    operators::ARITHMETIC,
+    operators::ARITHMETIC_SIDE_EFFECTS,
     operators::ASSIGN_OP_PATTERN,
     operators::BAD_BIT_MASK,
     operators::CMP_NAN,
@@ -457,7 +475,6 @@ store.register_lints(&[
     partialeq_to_none::PARTIALEQ_TO_NONE,
     pass_by_ref_or_value::LARGE_TYPES_PASSED_BY_VALUE,
     pass_by_ref_or_value::TRIVIALLY_COPY_PASS_BY_REF,
-    path_buf_push_overwrite::PATH_BUF_PUSH_OVERWRITE,
     pattern_type_mismatch::PATTERN_TYPE_MISMATCH,
     precedence::PRECEDENCE,
     ptr::CMP_NULL,
@@ -470,7 +487,6 @@ store.register_lints(&[
     ranges::MANUAL_RANGE_CONTAINS,
     ranges::RANGE_MINUS_ONE,
     ranges::RANGE_PLUS_ONE,
-    ranges::RANGE_ZIP_WITH_LEN,
     ranges::REVERSED_EMPTY_RANGES,
     rc_clone_in_vec_init::RC_CLONE_IN_VEC_INIT,
     read_zero_byte_vec::READ_ZERO_BYTE_VEC,
@@ -486,7 +502,6 @@ store.register_lints(&[
     reference::DEREF_ADDROF,
     regex::INVALID_REGEX,
     regex::TRIVIAL_REGEX,
-    repeat_once::REPEAT_ONCE,
     return_self_not_must_use::RETURN_SELF_NOT_MUST_USE,
     returns::LET_AND_RETURN,
     returns::NEEDLESS_RETURN,
@@ -501,7 +516,6 @@ store.register_lints(&[
     single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS,
     size_of_in_element_count::SIZE_OF_IN_ELEMENT_COUNT,
     slow_vector_initialization::SLOW_VECTOR_INITIALIZATION,
-    stable_sort_primitive::STABLE_SORT_PRIMITIVE,
     std_instead_of_core::ALLOC_INSTEAD_OF_CORE,
     std_instead_of_core::STD_INSTEAD_OF_ALLOC,
     std_instead_of_core::STD_INSTEAD_OF_CORE,
@@ -537,10 +551,10 @@ store.register_lints(&[
     transmute::TRANSMUTE_PTR_TO_PTR,
     transmute::TRANSMUTE_PTR_TO_REF,
     transmute::TRANSMUTE_UNDEFINED_REPR,
+    transmute::TRANSMUTING_NULL,
     transmute::UNSOUND_COLLECTION_TRANSMUTE,
     transmute::USELESS_TRANSMUTE,
     transmute::WRONG_TRANSMUTE,
-    transmuting_null::TRANSMUTING_NULL,
     types::BORROWED_BOX,
     types::BOX_COLLECTION,
     types::LINKEDLIST,
@@ -555,7 +569,6 @@ store.register_lints(&[
     unicode::NON_ASCII_LITERAL,
     unicode::UNICODE_NOT_NFC,
     uninit_vec::UNINIT_VEC,
-    unit_hash::UNIT_HASH,
     unit_return_expecting_ord::UNIT_RETURN_EXPECTING_ORD,
     unit_types::LET_UNIT_VALUE,
     unit_types::UNIT_ARG,
@@ -564,12 +577,12 @@ store.register_lints(&[
     unnamed_address::VTABLE_ADDRESS_COMPARISONS,
     unnecessary_owned_empty_strings::UNNECESSARY_OWNED_EMPTY_STRINGS,
     unnecessary_self_imports::UNNECESSARY_SELF_IMPORTS,
-    unnecessary_sort_by::UNNECESSARY_SORT_BY,
     unnecessary_wraps::UNNECESSARY_WRAPS,
     unnested_or_patterns::UNNESTED_OR_PATTERNS,
     unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME,
     unused_async::UNUSED_ASYNC,
     unused_io_amount::UNUSED_IO_AMOUNT,
+    unused_peekable::UNUSED_PEEKABLE,
     unused_rounding::UNUSED_ROUNDING,
     unused_self::UNUSED_SELF,
     unused_unit::UNUSED_UNIT,
@@ -581,8 +594,6 @@ store.register_lints(&[
     useless_conversion::USELESS_CONVERSION,
     vec::USELESS_VEC,
     vec_init_then_push::VEC_INIT_THEN_PUSH,
-    vec_resize_to_zero::VEC_RESIZE_TO_ZERO,
-    verbose_file_reads::VERBOSE_FILE_READS,
     wildcard_imports::ENUM_GLOB_USE,
     wildcard_imports::WILDCARD_IMPORTS,
     write::PRINTLN_EMPTY_STRING,
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_nursery.rs b/src/tools/clippy/clippy_lints/src/lib.register_nursery.rs
index 91210b23afe3..f1783dd9ddef 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_nursery.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_nursery.rs
@@ -14,22 +14,24 @@ store.register_group(true, "clippy::nursery", Some("clippy_nursery"), vec![
     LintId::of(index_refutable_slice::INDEX_REFUTABLE_SLICE),
     LintId::of(let_if_seq::USELESS_LET_IF_SEQ),
     LintId::of(matches::SIGNIFICANT_DROP_IN_SCRUTINEE),
+    LintId::of(methods::ITER_ON_EMPTY_COLLECTIONS),
+    LintId::of(methods::ITER_ON_SINGLE_ITEMS),
     LintId::of(methods::ITER_WITH_DRAIN),
+    LintId::of(methods::PATH_BUF_PUSH_OVERWRITE),
     LintId::of(missing_const_for_fn::MISSING_CONST_FOR_FN),
     LintId::of(mutable_debug_assertion::DEBUG_ASSERT_WITH_MUT_CALL),
     LintId::of(mutex_atomic::MUTEX_ATOMIC),
     LintId::of(mutex_atomic::MUTEX_INTEGER),
     LintId::of(non_send_fields_in_send_ty::NON_SEND_FIELDS_IN_SEND_TY),
     LintId::of(nonstandard_macro_braces::NONSTANDARD_MACRO_BRACES),
-    LintId::of(only_used_in_recursion::ONLY_USED_IN_RECURSION),
     LintId::of(option_if_let_else::OPTION_IF_LET_ELSE),
-    LintId::of(path_buf_push_overwrite::PATH_BUF_PUSH_OVERWRITE),
     LintId::of(redundant_pub_crate::REDUNDANT_PUB_CRATE),
     LintId::of(regex::TRIVIAL_REGEX),
     LintId::of(strings::STRING_LIT_AS_BYTES),
     LintId::of(suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
     LintId::of(trailing_empty_array::TRAILING_EMPTY_ARRAY),
     LintId::of(transmute::TRANSMUTE_UNDEFINED_REPR),
+    LintId::of(unused_peekable::UNUSED_PEEKABLE),
     LintId::of(unused_rounding::UNUSED_ROUNDING),
     LintId::of(use_self::USE_SELF),
 ])
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_pedantic.rs b/src/tools/clippy/clippy_lints/src/lib.register_pedantic.rs
index bd7d1a15ab4e..584ccf55e511 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_pedantic.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_pedantic.rs
@@ -4,9 +4,7 @@
 
 store.register_group(true, "clippy::pedantic", Some("clippy_pedantic"), vec![
     LintId::of(attrs::INLINE_ALWAYS),
-    LintId::of(borrow_as_ptr::BORROW_AS_PTR),
-    LintId::of(bytecount::NAIVE_BYTECOUNT),
-    LintId::of(case_sensitive_file_extension_comparisons::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS),
+    LintId::of(casts::BORROW_AS_PTR),
     LintId::of(casts::CAST_LOSSLESS),
     LintId::of(casts::CAST_POSSIBLE_TRUNCATION),
     LintId::of(casts::CAST_POSSIBLE_WRAP),
@@ -50,20 +48,24 @@ store.register_group(true, "clippy::pedantic", Some("clippy_pedantic"), vec![
     LintId::of(macro_use::MACRO_USE_IMPORTS),
     LintId::of(manual_assert::MANUAL_ASSERT),
     LintId::of(manual_instant_elapsed::MANUAL_INSTANT_ELAPSED),
-    LintId::of(manual_ok_or::MANUAL_OK_OR),
+    LintId::of(manual_string_new::MANUAL_STRING_NEW),
     LintId::of(matches::MATCH_BOOL),
     LintId::of(matches::MATCH_ON_VEC_ITEMS),
     LintId::of(matches::MATCH_SAME_ARMS),
     LintId::of(matches::MATCH_WILDCARD_FOR_SINGLE_VARIANTS),
     LintId::of(matches::MATCH_WILD_ERR_ARM),
     LintId::of(matches::SINGLE_MATCH_ELSE),
+    LintId::of(methods::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS),
     LintId::of(methods::CLONED_INSTEAD_OF_COPIED),
     LintId::of(methods::FILTER_MAP_NEXT),
     LintId::of(methods::FLAT_MAP_OPTION),
     LintId::of(methods::FROM_ITER_INSTEAD_OF_COLLECT),
     LintId::of(methods::IMPLICIT_CLONE),
     LintId::of(methods::INEFFICIENT_TO_STRING),
+    LintId::of(methods::MANUAL_OK_OR),
     LintId::of(methods::MAP_UNWRAP_OR),
+    LintId::of(methods::NAIVE_BYTECOUNT),
+    LintId::of(methods::STABLE_SORT_PRIMITIVE),
     LintId::of(methods::UNNECESSARY_JOIN),
     LintId::of(misc::USED_UNDERSCORE_BINDING),
     LintId::of(mismatching_type_param_order::MISMATCHING_TYPE_PARAM_ORDER),
@@ -85,7 +87,6 @@ store.register_group(true, "clippy::pedantic", Some("clippy_pedantic"), vec![
     LintId::of(ref_option_ref::REF_OPTION_REF),
     LintId::of(return_self_not_must_use::RETURN_SELF_NOT_MUST_USE),
     LintId::of(semicolon_if_nothing_returned::SEMICOLON_IF_NOTHING_RETURNED),
-    LintId::of(stable_sort_primitive::STABLE_SORT_PRIMITIVE),
     LintId::of(strings::STRING_ADD_ASSIGN),
     LintId::of(trait_bounds::TRAIT_DUPLICATION_IN_BOUNDS),
     LintId::of(trait_bounds::TYPE_REPETITION_IN_BOUNDS),
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_perf.rs b/src/tools/clippy/clippy_lints/src/lib.register_perf.rs
index e1b90acb93c2..195ce41e31e9 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_perf.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_perf.rs
@@ -7,12 +7,14 @@ store.register_group(true, "clippy::perf", Some("clippy_perf"), vec![
     LintId::of(escape::BOXED_LOCAL),
     LintId::of(format_args::FORMAT_IN_FORMAT_ARGS),
     LintId::of(format_args::TO_STRING_IN_FORMAT_ARGS),
+    LintId::of(functions::RESULT_LARGE_ERR),
     LintId::of(large_const_arrays::LARGE_CONST_ARRAYS),
     LintId::of(large_enum_variant::LARGE_ENUM_VARIANT),
     LintId::of(loops::MANUAL_MEMCPY),
     LintId::of(loops::MISSING_SPIN_LOOP),
     LintId::of(loops::NEEDLESS_COLLECT),
     LintId::of(manual_retain::MANUAL_RETAIN),
+    LintId::of(methods::COLLAPSIBLE_STR_REPLACE),
     LintId::of(methods::EXPECT_FUN_CALL),
     LintId::of(methods::EXTEND_WITH_DRAIN),
     LintId::of(methods::ITER_NTH),
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_restriction.rs b/src/tools/clippy/clippy_lints/src/lib.register_restriction.rs
index a7339ef27217..6eb9b3d3b9b7 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_restriction.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_restriction.rs
@@ -4,11 +4,11 @@
 
 store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
     LintId::of(as_conversions::AS_CONVERSIONS),
-    LintId::of(as_underscore::AS_UNDERSCORE),
     LintId::of(asm_syntax::INLINE_ASM_X86_ATT_SYNTAX),
     LintId::of(asm_syntax::INLINE_ASM_X86_INTEL_SYNTAX),
     LintId::of(assertions_on_result_states::ASSERTIONS_ON_RESULT_STATES),
     LintId::of(attrs::ALLOW_ATTRIBUTES_WITHOUT_REASON),
+    LintId::of(casts::AS_UNDERSCORE),
     LintId::of(casts::FN_TO_NUMERIC_CAST_ANY),
     LintId::of(create_dir::CREATE_DIR),
     LintId::of(dbg_macro::DBG_MACRO),
@@ -30,7 +30,6 @@ store.register_group(true, "clippy::restriction", Some("clippy_restriction"), ve
     LintId::of(large_include_file::LARGE_INCLUDE_FILE),
     LintId::of(let_underscore::LET_UNDERSCORE_MUST_USE),
     LintId::of(literal_representation::DECIMAL_LITERAL_REPRESENTATION),
-    LintId::of(map_err_ignore::MAP_ERR_IGNORE),
     LintId::of(matches::REST_PAT_IN_FULLY_BOUND_STRUCTS),
     LintId::of(matches::TRY_ERR),
     LintId::of(matches::WILDCARD_ENUM_MATCH_ARM),
@@ -39,7 +38,9 @@ store.register_group(true, "clippy::restriction", Some("clippy_restriction"), ve
     LintId::of(methods::EXPECT_USED),
     LintId::of(methods::FILETYPE_IS_FILE),
     LintId::of(methods::GET_UNWRAP),
+    LintId::of(methods::MAP_ERR_IGNORE),
     LintId::of(methods::UNWRAP_USED),
+    LintId::of(methods::VERBOSE_FILE_READS),
     LintId::of(misc_early::SEPARATED_LITERAL_SUFFIX),
     LintId::of(misc_early::UNNEEDED_FIELD_PATTERN),
     LintId::of(misc_early::UNSEPARATED_LITERAL_SUFFIX),
@@ -49,7 +50,7 @@ store.register_group(true, "clippy::restriction", Some("clippy_restriction"), ve
     LintId::of(mixed_read_write_in_expression::MIXED_READ_WRITE_IN_EXPRESSION),
     LintId::of(module_style::MOD_MODULE_FILES),
     LintId::of(module_style::SELF_NAMED_MODULE_FILES),
-    LintId::of(operators::ARITHMETIC),
+    LintId::of(operators::ARITHMETIC_SIDE_EFFECTS),
     LintId::of(operators::FLOAT_ARITHMETIC),
     LintId::of(operators::FLOAT_CMP_CONST),
     LintId::of(operators::INTEGER_ARITHMETIC),
@@ -81,7 +82,6 @@ store.register_group(true, "clippy::restriction", Some("clippy_restriction"), ve
     LintId::of(unicode::NON_ASCII_LITERAL),
     LintId::of(unnecessary_self_imports::UNNECESSARY_SELF_IMPORTS),
     LintId::of(unwrap_in_result::UNWRAP_IN_RESULT),
-    LintId::of(verbose_file_reads::VERBOSE_FILE_READS),
     LintId::of(write::PRINT_STDERR),
     LintId::of(write::PRINT_STDOUT),
     LintId::of(write::USE_DEBUG),
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_style.rs b/src/tools/clippy/clippy_lints/src/lib.register_style.rs
index bfa654238f13..05d2ec2e9e1e 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_style.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_style.rs
@@ -6,6 +6,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(assertions_on_constants::ASSERTIONS_ON_CONSTANTS),
     LintId::of(blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS),
     LintId::of(bool_assert_comparison::BOOL_ASSERT_COMPARISON),
+    LintId::of(bool_to_int_with_if::BOOL_TO_INT_WITH_IF),
     LintId::of(casts::FN_TO_NUMERIC_CAST),
     LintId::of(casts::FN_TO_NUMERIC_CAST_WITH_TRUNCATION),
     LintId::of(collapsible_if::COLLAPSIBLE_ELSE_IF),
@@ -29,7 +30,6 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(functions::DOUBLE_MUST_USE),
     LintId::of(functions::MUST_USE_UNIT),
     LintId::of(functions::RESULT_UNIT_ERR),
-    LintId::of(get_first::GET_FIRST),
     LintId::of(inherent_to_string::INHERENT_TO_STRING),
     LintId::of(init_numbered_fields::INIT_NUMBERED_FIELDS),
     LintId::of(len_zero::COMPARISON_TO_EMPTY),
@@ -45,7 +45,6 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(manual_async_fn::MANUAL_ASYNC_FN),
     LintId::of(manual_bits::MANUAL_BITS),
     LintId::of(manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
-    LintId::of(map_clone::MAP_CLONE),
     LintId::of(match_result_ok::MATCH_RESULT_OK),
     LintId::of(matches::COLLAPSIBLE_MATCH),
     LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
@@ -61,6 +60,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(methods::CHARS_LAST_CMP),
     LintId::of(methods::CHARS_NEXT_CMP),
     LintId::of(methods::ERR_EXPECT),
+    LintId::of(methods::GET_FIRST),
     LintId::of(methods::INTO_ITER_ON_REF),
     LintId::of(methods::IS_DIGIT_ASCII_RADIX),
     LintId::of(methods::ITER_CLONED_COLLECT),
@@ -68,7 +68,9 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(methods::ITER_NTH_ZERO),
     LintId::of(methods::ITER_SKIP_NEXT),
     LintId::of(methods::MANUAL_SATURATING_ARITHMETIC),
+    LintId::of(methods::MAP_CLONE),
     LintId::of(methods::MAP_COLLECT_RESULT_UNIT),
+    LintId::of(methods::MUT_MUTEX_LOCK),
     LintId::of(methods::NEW_RET_NO_SELF),
     LintId::of(methods::OBFUSCATED_IF_ELSE),
     LintId::of(methods::OK_EXPECT),
@@ -88,7 +90,6 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(misc_early::DUPLICATE_UNDERSCORE_ARGUMENT),
     LintId::of(misc_early::MIXED_CASE_HEX_LITERALS),
     LintId::of(misc_early::REDUNDANT_PATTERN),
-    LintId::of(mut_mutex_lock::MUT_MUTEX_LOCK),
     LintId::of(mut_reference::UNNECESSARY_MUT_PASSED),
     LintId::of(needless_late_init::NEEDLESS_LATE_INIT),
     LintId::of(needless_parens_on_range_literals::NEEDLESS_PARENS_ON_RANGE_LITERALS),
diff --git a/src/tools/clippy/clippy_lints/src/lib.register_suspicious.rs b/src/tools/clippy/clippy_lints/src/lib.register_suspicious.rs
index 964992bd94fe..6125d0f7a862 100644
--- a/src/tools/clippy/clippy_lints/src/lib.register_suspicious.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.register_suspicious.rs
@@ -11,6 +11,7 @@ store.register_group(true, "clippy::suspicious", Some("clippy_suspicious"), vec!
     LintId::of(casts::CAST_ABS_TO_UNSIGNED),
     LintId::of(casts::CAST_ENUM_CONSTRUCTOR),
     LintId::of(casts::CAST_ENUM_TRUNCATION),
+    LintId::of(casts::CAST_SLICE_FROM_RAW_PARTS),
     LintId::of(crate_in_macro_def::CRATE_IN_MACRO_DEF),
     LintId::of(drop_forget_ref::DROP_NON_DROP),
     LintId::of(drop_forget_ref::FORGET_NON_DROP),
@@ -24,6 +25,8 @@ store.register_group(true, "clippy::suspicious", Some("clippy_suspicious"), vec!
     LintId::of(loops::MUT_RANGE_BOUND),
     LintId::of(methods::NO_EFFECT_REPLACE),
     LintId::of(methods::SUSPICIOUS_MAP),
+    LintId::of(methods::SUSPICIOUS_TO_OWNED),
+    LintId::of(multi_assignments::MULTI_ASSIGNMENTS),
     LintId::of(mut_key::MUTABLE_KEY_TYPE),
     LintId::of(octal_escapes::OCTAL_ESCAPES),
     LintId::of(operators::FLOAT_EQUALITY_WITHOUT_ABS),
diff --git a/src/tools/clippy/clippy_lints/src/lib.rs b/src/tools/clippy/clippy_lints/src/lib.rs
index ec5c73c13576..00bf6445c12d 100644
--- a/src/tools/clippy/clippy_lints/src/lib.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.rs
@@ -5,7 +5,6 @@
 #![feature(drain_filter)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(lint_reasons)]
 #![feature(never_type)]
 #![feature(once_cell)]
@@ -40,7 +39,6 @@ extern crate rustc_lint;
 extern crate rustc_middle;
 extern crate rustc_mir_dataflow;
 extern crate rustc_parse;
-extern crate rustc_parse_format;
 extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_target;
@@ -171,7 +169,6 @@ mod renamed_lints;
 mod almost_complete_letter_range;
 mod approx_const;
 mod as_conversions;
-mod as_underscore;
 mod asm_syntax;
 mod assertions_on_constants;
 mod assertions_on_result_states;
@@ -180,13 +177,10 @@ mod attrs;
 mod await_holding_invalid;
 mod blocks_in_if_conditions;
 mod bool_assert_comparison;
+mod bool_to_int_with_if;
 mod booleans;
-mod borrow_as_ptr;
 mod borrow_deref_ref;
-mod bytecount;
-mod bytes_count_to_len;
 mod cargo;
-mod case_sensitive_file_extension_comparisons;
 mod casts;
 mod checked_conversions;
 mod cognitive_complexity;
@@ -239,7 +233,6 @@ mod from_over_into;
 mod from_str_radix_10;
 mod functions;
 mod future_not_send;
-mod get_first;
 mod if_let_mutex;
 mod if_not_else;
 mod if_then_some_else_none;
@@ -276,12 +269,10 @@ mod manual_async_fn;
 mod manual_bits;
 mod manual_instant_elapsed;
 mod manual_non_exhaustive;
-mod manual_ok_or;
 mod manual_rem_euclid;
 mod manual_retain;
+mod manual_string_new;
 mod manual_strip;
-mod map_clone;
-mod map_err_ignore;
 mod map_unit_fn;
 mod match_result_ok;
 mod matches;
@@ -298,9 +289,9 @@ mod missing_enforced_import_rename;
 mod missing_inline;
 mod mixed_read_write_in_expression;
 mod module_style;
+mod multi_assignments;
 mod mut_key;
 mod mut_mut;
-mod mut_mutex_lock;
 mod mut_reference;
 mod mutable_debug_assertion;
 mod mutex_atomic;
@@ -325,7 +316,6 @@ mod non_send_fields_in_send_ty;
 mod nonstandard_macro_braces;
 mod octal_escapes;
 mod only_used_in_recursion;
-mod open_options;
 mod operators;
 mod option_env_unwrap;
 mod option_if_let_else;
@@ -335,7 +325,6 @@ mod panic_unimplemented;
 mod partialeq_ne_impl;
 mod partialeq_to_none;
 mod pass_by_ref_or_value;
-mod path_buf_push_overwrite;
 mod pattern_type_mismatch;
 mod precedence;
 mod ptr;
@@ -355,7 +344,6 @@ mod redundant_static_lifetimes;
 mod ref_option_ref;
 mod reference;
 mod regex;
-mod repeat_once;
 mod return_self_not_must_use;
 mod returns;
 mod same_name_method;
@@ -367,7 +355,6 @@ mod single_char_lifetime_names;
 mod single_component_path_imports;
 mod size_of_in_element_count;
 mod slow_vector_initialization;
-mod stable_sort_primitive;
 mod std_instead_of_core;
 mod strings;
 mod strlen_on_c_strings;
@@ -381,23 +368,21 @@ mod to_digit_is_some;
 mod trailing_empty_array;
 mod trait_bounds;
 mod transmute;
-mod transmuting_null;
 mod types;
 mod undocumented_unsafe_blocks;
 mod unicode;
 mod uninit_vec;
-mod unit_hash;
 mod unit_return_expecting_ord;
 mod unit_types;
 mod unnamed_address;
 mod unnecessary_owned_empty_strings;
 mod unnecessary_self_imports;
-mod unnecessary_sort_by;
 mod unnecessary_wraps;
 mod unnested_or_patterns;
 mod unsafe_removed_from_name;
 mod unused_async;
 mod unused_io_amount;
+mod unused_peekable;
 mod unused_rounding;
 mod unused_self;
 mod unused_unit;
@@ -408,8 +393,6 @@ mod use_self;
 mod useless_conversion;
 mod vec;
 mod vec_init_then_push;
-mod vec_resize_to_zero;
-mod verbose_file_reads;
 mod wildcard_imports;
 mod write;
 mod zero_div_zero;
@@ -440,7 +423,6 @@ pub fn register_pre_expansion_lints(store: &mut rustc_lint::LintStore, sess: &Se
         })
     });
 
-    store.register_pre_expansion_pass(|| Box::new(write::Write::default()));
     store.register_pre_expansion_pass(move || Box::new(attrs::EarlyAttributes { msrv }));
 }
 
@@ -539,7 +521,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     #[cfg(feature = "internal")]
     {
         if std::env::var("ENABLE_METADATA_COLLECTION").eq(&Ok("1".to_string())) {
-            store.register_late_pass(|| Box::new(utils::internal_lints::metadata_collector::MetadataCollector::new()));
+            store.register_late_pass(|_| Box::new(utils::internal_lints::metadata_collector::MetadataCollector::new()));
             return;
         }
     }
@@ -549,70 +531,73 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     {
         store.register_early_pass(|| Box::new(utils::internal_lints::ClippyLintsInternal));
         store.register_early_pass(|| Box::new(utils::internal_lints::ProduceIce));
-        store.register_late_pass(|| Box::new(utils::internal_lints::CollapsibleCalls));
-        store.register_late_pass(|| Box::new(utils::internal_lints::CompilerLintFunctions::new()));
-        store.register_late_pass(|| Box::new(utils::internal_lints::IfChainStyle));
-        store.register_late_pass(|| Box::new(utils::internal_lints::InvalidPaths));
-        store.register_late_pass(|| Box::new(utils::internal_lints::InterningDefinedSymbol::default()));
-        store.register_late_pass(|| Box::new(utils::internal_lints::LintWithoutLintPass::default()));
-        store.register_late_pass(|| Box::new(utils::internal_lints::MatchTypeOnDiagItem));
-        store.register_late_pass(|| Box::new(utils::internal_lints::OuterExpnDataPass));
-        store.register_late_pass(|| Box::new(utils::internal_lints::MsrvAttrImpl));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::CollapsibleCalls));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::CompilerLintFunctions::new()));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::IfChainStyle));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::InvalidPaths));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::InterningDefinedSymbol::default()));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::LintWithoutLintPass::default()));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::MatchTypeOnDiagItem));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::OuterExpnDataPass));
+        store.register_late_pass(|_| Box::new(utils::internal_lints::MsrvAttrImpl));
     }
 
-    let arithmetic_allowed = conf.arithmetic_allowed.clone();
-    store.register_late_pass(move || Box::new(operators::arithmetic::Arithmetic::new(arithmetic_allowed.clone())));
-    store.register_late_pass(|| Box::new(utils::dump_hir::DumpHir));
-    store.register_late_pass(|| Box::new(utils::author::Author));
+    let arithmetic_side_effects_allowed = conf.arithmetic_side_effects_allowed.clone();
+    store.register_late_pass(move |_| {
+        Box::new(operators::arithmetic_side_effects::ArithmeticSideEffects::new(
+            arithmetic_side_effects_allowed.clone(),
+        ))
+    });
+    store.register_late_pass(|_| Box::new(utils::dump_hir::DumpHir));
+    store.register_late_pass(|_| Box::new(utils::author::Author));
     let await_holding_invalid_types = conf.await_holding_invalid_types.clone();
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(await_holding_invalid::AwaitHolding::new(
             await_holding_invalid_types.clone(),
         ))
     });
-    store.register_late_pass(|| Box::new(serde_api::SerdeApi));
+    store.register_late_pass(|_| Box::new(serde_api::SerdeApi));
     let vec_box_size_threshold = conf.vec_box_size_threshold;
     let type_complexity_threshold = conf.type_complexity_threshold;
     let avoid_breaking_exported_api = conf.avoid_breaking_exported_api;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(types::Types::new(
             vec_box_size_threshold,
             type_complexity_threshold,
             avoid_breaking_exported_api,
         ))
     });
-    store.register_late_pass(|| Box::new(booleans::NonminimalBool));
-    store.register_late_pass(|| Box::new(enum_clike::UnportableVariant));
-    store.register_late_pass(|| Box::new(float_literal::FloatLiteral));
-    store.register_late_pass(|| Box::new(ptr::Ptr));
-    store.register_late_pass(|| Box::new(needless_bool::NeedlessBool));
-    store.register_late_pass(|| Box::new(needless_bool::BoolComparison));
-    store.register_late_pass(|| Box::new(needless_for_each::NeedlessForEach));
-    store.register_late_pass(|| Box::new(misc::MiscLints));
-    store.register_late_pass(|| Box::new(eta_reduction::EtaReduction));
-    store.register_late_pass(|| Box::new(mut_mut::MutMut));
-    store.register_late_pass(|| Box::new(mut_reference::UnnecessaryMutPassed));
-    store.register_late_pass(|| Box::new(len_zero::LenZero));
-    store.register_late_pass(|| Box::new(attrs::Attributes));
-    store.register_late_pass(|| Box::new(blocks_in_if_conditions::BlocksInIfConditions));
-    store.register_late_pass(|| Box::new(unicode::Unicode));
-    store.register_late_pass(|| Box::new(uninit_vec::UninitVec));
-    store.register_late_pass(|| Box::new(unit_hash::UnitHash));
-    store.register_late_pass(|| Box::new(unit_return_expecting_ord::UnitReturnExpectingOrd));
-    store.register_late_pass(|| Box::new(strings::StringAdd));
-    store.register_late_pass(|| Box::new(implicit_return::ImplicitReturn));
-    store.register_late_pass(|| Box::new(implicit_saturating_sub::ImplicitSaturatingSub));
-    store.register_late_pass(|| Box::new(default_numeric_fallback::DefaultNumericFallback));
-    store.register_late_pass(|| Box::new(inconsistent_struct_constructor::InconsistentStructConstructor));
-    store.register_late_pass(|| Box::new(non_octal_unix_permissions::NonOctalUnixPermissions));
+    store.register_late_pass(|_| Box::new(booleans::NonminimalBool));
+    store.register_late_pass(|_| Box::new(enum_clike::UnportableVariant));
+    store.register_late_pass(|_| Box::new(float_literal::FloatLiteral));
+    store.register_late_pass(|_| Box::new(ptr::Ptr));
+    store.register_late_pass(|_| Box::new(needless_bool::NeedlessBool));
+    store.register_late_pass(|_| Box::new(needless_bool::BoolComparison));
+    store.register_late_pass(|_| Box::new(needless_for_each::NeedlessForEach));
+    store.register_late_pass(|_| Box::new(misc::MiscLints));
+    store.register_late_pass(|_| Box::new(eta_reduction::EtaReduction));
+    store.register_late_pass(|_| Box::new(mut_mut::MutMut));
+    store.register_late_pass(|_| Box::new(mut_reference::UnnecessaryMutPassed));
+    store.register_late_pass(|_| Box::new(len_zero::LenZero));
+    store.register_late_pass(|_| Box::new(attrs::Attributes));
+    store.register_late_pass(|_| Box::new(blocks_in_if_conditions::BlocksInIfConditions));
+    store.register_late_pass(|_| Box::new(unicode::Unicode));
+    store.register_late_pass(|_| Box::new(uninit_vec::UninitVec));
+    store.register_late_pass(|_| Box::new(unit_return_expecting_ord::UnitReturnExpectingOrd));
+    store.register_late_pass(|_| Box::new(strings::StringAdd));
+    store.register_late_pass(|_| Box::new(implicit_return::ImplicitReturn));
+    store.register_late_pass(|_| Box::new(implicit_saturating_sub::ImplicitSaturatingSub));
+    store.register_late_pass(|_| Box::new(default_numeric_fallback::DefaultNumericFallback));
+    store.register_late_pass(|_| Box::new(inconsistent_struct_constructor::InconsistentStructConstructor));
+    store.register_late_pass(|_| Box::new(non_octal_unix_permissions::NonOctalUnixPermissions));
     store.register_early_pass(|| Box::new(unnecessary_self_imports::UnnecessarySelfImports));
 
     let msrv = read_msrv(conf, sess);
     let avoid_breaking_exported_api = conf.avoid_breaking_exported_api;
     let allow_expect_in_tests = conf.allow_expect_in_tests;
     let allow_unwrap_in_tests = conf.allow_unwrap_in_tests;
-    store.register_late_pass(move || Box::new(approx_const::ApproxConstant::new(msrv)));
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| Box::new(approx_const::ApproxConstant::new(msrv)));
+    store.register_late_pass(move |_| {
         Box::new(methods::Methods::new(
             avoid_breaking_exported_api,
             msrv,
@@ -620,154 +605,148 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
             allow_unwrap_in_tests,
         ))
     });
-    store.register_late_pass(move || Box::new(matches::Matches::new(msrv)));
+    store.register_late_pass(move |_| Box::new(matches::Matches::new(msrv)));
     store.register_early_pass(move || Box::new(manual_non_exhaustive::ManualNonExhaustiveStruct::new(msrv)));
-    store.register_late_pass(move || Box::new(manual_non_exhaustive::ManualNonExhaustiveEnum::new(msrv)));
-    store.register_late_pass(move || Box::new(manual_strip::ManualStrip::new(msrv)));
+    store.register_late_pass(move |_| Box::new(manual_non_exhaustive::ManualNonExhaustiveEnum::new(msrv)));
+    store.register_late_pass(move |_| Box::new(manual_strip::ManualStrip::new(msrv)));
     store.register_early_pass(move || Box::new(redundant_static_lifetimes::RedundantStaticLifetimes::new(msrv)));
     store.register_early_pass(move || Box::new(redundant_field_names::RedundantFieldNames::new(msrv)));
-    store.register_late_pass(move || Box::new(checked_conversions::CheckedConversions::new(msrv)));
-    store.register_late_pass(move || Box::new(mem_replace::MemReplace::new(msrv)));
-    store.register_late_pass(move || Box::new(ranges::Ranges::new(msrv)));
-    store.register_late_pass(move || Box::new(from_over_into::FromOverInto::new(msrv)));
-    store.register_late_pass(move || Box::new(use_self::UseSelf::new(msrv)));
-    store.register_late_pass(move || Box::new(missing_const_for_fn::MissingConstForFn::new(msrv)));
-    store.register_late_pass(move || Box::new(needless_question_mark::NeedlessQuestionMark));
-    store.register_late_pass(move || Box::new(casts::Casts::new(msrv)));
+    store.register_late_pass(move |_| Box::new(checked_conversions::CheckedConversions::new(msrv)));
+    store.register_late_pass(move |_| Box::new(mem_replace::MemReplace::new(msrv)));
+    store.register_late_pass(move |_| Box::new(ranges::Ranges::new(msrv)));
+    store.register_late_pass(move |_| Box::new(from_over_into::FromOverInto::new(msrv)));
+    store.register_late_pass(move |_| Box::new(use_self::UseSelf::new(msrv)));
+    store.register_late_pass(move |_| Box::new(missing_const_for_fn::MissingConstForFn::new(msrv)));
+    store.register_late_pass(move |_| Box::new(needless_question_mark::NeedlessQuestionMark));
+    store.register_late_pass(move |_| Box::new(casts::Casts::new(msrv)));
     store.register_early_pass(move || Box::new(unnested_or_patterns::UnnestedOrPatterns::new(msrv)));
-    store.register_late_pass(move || Box::new(map_clone::MapClone::new(msrv)));
-
-    store.register_late_pass(|| Box::new(size_of_in_element_count::SizeOfInElementCount));
-    store.register_late_pass(|| Box::new(same_name_method::SameNameMethod));
+    store.register_late_pass(|_| Box::new(size_of_in_element_count::SizeOfInElementCount));
+    store.register_late_pass(|_| Box::new(same_name_method::SameNameMethod));
     let max_suggested_slice_pattern_length = conf.max_suggested_slice_pattern_length;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(index_refutable_slice::IndexRefutableSlice::new(
             max_suggested_slice_pattern_length,
             msrv,
         ))
     });
-    store.register_late_pass(|| Box::new(map_err_ignore::MapErrIgnore));
-    store.register_late_pass(|| Box::new(shadow::Shadow::default()));
-    store.register_late_pass(|| Box::new(unit_types::UnitTypes));
-    store.register_late_pass(|| Box::new(loops::Loops));
-    store.register_late_pass(|| Box::new(main_recursion::MainRecursion::default()));
-    store.register_late_pass(|| Box::new(lifetimes::Lifetimes));
-    store.register_late_pass(|| Box::new(entry::HashMapPass));
-    store.register_late_pass(|| Box::new(minmax::MinMaxPass));
-    store.register_late_pass(|| Box::new(open_options::OpenOptions));
-    store.register_late_pass(|| Box::new(zero_div_zero::ZeroDiv));
-    store.register_late_pass(|| Box::new(mutex_atomic::Mutex));
-    store.register_late_pass(|| Box::new(needless_update::NeedlessUpdate));
-    store.register_late_pass(|| Box::new(needless_borrowed_ref::NeedlessBorrowedRef));
-    store.register_late_pass(|| Box::new(borrow_deref_ref::BorrowDerefRef));
-    store.register_late_pass(|| Box::new(no_effect::NoEffect));
-    store.register_late_pass(|| Box::new(temporary_assignment::TemporaryAssignment));
-    store.register_late_pass(move || Box::new(transmute::Transmute::new(msrv)));
+    store.register_late_pass(|_| Box::new(shadow::Shadow::default()));
+    store.register_late_pass(|_| Box::new(unit_types::UnitTypes));
+    store.register_late_pass(|_| Box::new(loops::Loops));
+    store.register_late_pass(|_| Box::new(main_recursion::MainRecursion::default()));
+    store.register_late_pass(|_| Box::new(lifetimes::Lifetimes));
+    store.register_late_pass(|_| Box::new(entry::HashMapPass));
+    store.register_late_pass(|_| Box::new(minmax::MinMaxPass));
+    store.register_late_pass(|_| Box::new(zero_div_zero::ZeroDiv));
+    store.register_late_pass(|_| Box::new(mutex_atomic::Mutex));
+    store.register_late_pass(|_| Box::new(needless_update::NeedlessUpdate));
+    store.register_late_pass(|_| Box::new(needless_borrowed_ref::NeedlessBorrowedRef));
+    store.register_late_pass(|_| Box::new(borrow_deref_ref::BorrowDerefRef));
+    store.register_late_pass(|_| Box::new(no_effect::NoEffect));
+    store.register_late_pass(|_| Box::new(temporary_assignment::TemporaryAssignment));
+    store.register_late_pass(move |_| Box::new(transmute::Transmute::new(msrv)));
     let cognitive_complexity_threshold = conf.cognitive_complexity_threshold;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(cognitive_complexity::CognitiveComplexity::new(
             cognitive_complexity_threshold,
         ))
     });
     let too_large_for_stack = conf.too_large_for_stack;
-    store.register_late_pass(move || Box::new(escape::BoxedLocal { too_large_for_stack }));
-    store.register_late_pass(move || Box::new(vec::UselessVec { too_large_for_stack }));
-    store.register_late_pass(|| Box::new(panic_unimplemented::PanicUnimplemented));
-    store.register_late_pass(|| Box::new(strings::StringLitAsBytes));
-    store.register_late_pass(|| Box::new(derive::Derive));
-    store.register_late_pass(|| Box::new(derivable_impls::DerivableImpls));
-    store.register_late_pass(|| Box::new(drop_forget_ref::DropForgetRef));
-    store.register_late_pass(|| Box::new(empty_enum::EmptyEnum));
-    store.register_late_pass(|| Box::new(invalid_upcast_comparisons::InvalidUpcastComparisons));
-    store.register_late_pass(|| Box::new(regex::Regex));
-    store.register_late_pass(|| Box::new(copies::CopyAndPaste));
-    store.register_late_pass(|| Box::new(copy_iterator::CopyIterator));
-    store.register_late_pass(|| Box::new(format::UselessFormat));
-    store.register_late_pass(|| Box::new(swap::Swap));
-    store.register_late_pass(|| Box::new(overflow_check_conditional::OverflowCheckConditional));
-    store.register_late_pass(|| Box::new(new_without_default::NewWithoutDefault::default()));
+    store.register_late_pass(move |_| Box::new(escape::BoxedLocal { too_large_for_stack }));
+    store.register_late_pass(move |_| Box::new(vec::UselessVec { too_large_for_stack }));
+    store.register_late_pass(|_| Box::new(panic_unimplemented::PanicUnimplemented));
+    store.register_late_pass(|_| Box::new(strings::StringLitAsBytes));
+    store.register_late_pass(|_| Box::new(derive::Derive));
+    store.register_late_pass(|_| Box::new(derivable_impls::DerivableImpls));
+    store.register_late_pass(|_| Box::new(drop_forget_ref::DropForgetRef));
+    store.register_late_pass(|_| Box::new(empty_enum::EmptyEnum));
+    store.register_late_pass(|_| Box::new(invalid_upcast_comparisons::InvalidUpcastComparisons));
+    store.register_late_pass(|_| Box::new(regex::Regex));
+    store.register_late_pass(|_| Box::new(copies::CopyAndPaste));
+    store.register_late_pass(|_| Box::new(copy_iterator::CopyIterator));
+    store.register_late_pass(|_| Box::new(format::UselessFormat));
+    store.register_late_pass(|_| Box::new(swap::Swap));
+    store.register_late_pass(|_| Box::new(overflow_check_conditional::OverflowCheckConditional));
+    store.register_late_pass(|_| Box::new(new_without_default::NewWithoutDefault::default()));
     let disallowed_names = conf.disallowed_names.iter().cloned().collect::<FxHashSet<_>>();
-    store.register_late_pass(move || Box::new(disallowed_names::DisallowedNames::new(disallowed_names.clone())));
+    store.register_late_pass(move |_| Box::new(disallowed_names::DisallowedNames::new(disallowed_names.clone())));
     let too_many_arguments_threshold = conf.too_many_arguments_threshold;
     let too_many_lines_threshold = conf.too_many_lines_threshold;
-    store.register_late_pass(move || {
+    let large_error_threshold = conf.large_error_threshold;
+    store.register_late_pass(move |_| {
         Box::new(functions::Functions::new(
             too_many_arguments_threshold,
             too_many_lines_threshold,
+            large_error_threshold,
         ))
     });
     let doc_valid_idents = conf.doc_valid_idents.iter().cloned().collect::<FxHashSet<_>>();
-    store.register_late_pass(move || Box::new(doc::DocMarkdown::new(doc_valid_idents.clone())));
-    store.register_late_pass(|| Box::new(neg_multiply::NegMultiply));
-    store.register_late_pass(|| Box::new(mem_forget::MemForget));
-    store.register_late_pass(|| Box::new(let_if_seq::LetIfSeq));
-    store.register_late_pass(|| Box::new(mixed_read_write_in_expression::EvalOrderDependence));
-    store.register_late_pass(|| Box::new(missing_doc::MissingDoc::new()));
-    store.register_late_pass(|| Box::new(missing_inline::MissingInline));
-    store.register_late_pass(move || Box::new(exhaustive_items::ExhaustiveItems));
-    store.register_late_pass(|| Box::new(match_result_ok::MatchResultOk));
-    store.register_late_pass(|| Box::new(partialeq_ne_impl::PartialEqNeImpl));
-    store.register_late_pass(|| Box::new(unused_io_amount::UnusedIoAmount));
+    store.register_late_pass(move |_| Box::new(doc::DocMarkdown::new(doc_valid_idents.clone())));
+    store.register_late_pass(|_| Box::new(neg_multiply::NegMultiply));
+    store.register_late_pass(|_| Box::new(mem_forget::MemForget));
+    store.register_late_pass(|_| Box::new(let_if_seq::LetIfSeq));
+    store.register_late_pass(|_| Box::new(mixed_read_write_in_expression::EvalOrderDependence));
+    store.register_late_pass(|_| Box::new(missing_doc::MissingDoc::new()));
+    store.register_late_pass(|_| Box::new(missing_inline::MissingInline));
+    store.register_late_pass(move |_| Box::new(exhaustive_items::ExhaustiveItems));
+    store.register_late_pass(|_| Box::new(match_result_ok::MatchResultOk));
+    store.register_late_pass(|_| Box::new(partialeq_ne_impl::PartialEqNeImpl));
+    store.register_late_pass(|_| Box::new(unused_io_amount::UnusedIoAmount));
     let enum_variant_size_threshold = conf.enum_variant_size_threshold;
-    store.register_late_pass(move || Box::new(large_enum_variant::LargeEnumVariant::new(enum_variant_size_threshold)));
-    store.register_late_pass(|| Box::new(explicit_write::ExplicitWrite));
-    store.register_late_pass(|| Box::new(needless_pass_by_value::NeedlessPassByValue));
+    store.register_late_pass(move |_| Box::new(large_enum_variant::LargeEnumVariant::new(enum_variant_size_threshold)));
+    store.register_late_pass(|_| Box::new(explicit_write::ExplicitWrite));
+    store.register_late_pass(|_| Box::new(needless_pass_by_value::NeedlessPassByValue));
     let pass_by_ref_or_value = pass_by_ref_or_value::PassByRefOrValue::new(
         conf.trivial_copy_size_limit,
         conf.pass_by_value_size_limit,
         conf.avoid_breaking_exported_api,
         &sess.target,
     );
-    store.register_late_pass(move || Box::new(pass_by_ref_or_value));
-    store.register_late_pass(|| Box::new(ref_option_ref::RefOptionRef));
-    store.register_late_pass(|| Box::new(bytecount::ByteCount));
-    store.register_late_pass(|| Box::new(infinite_iter::InfiniteIter));
-    store.register_late_pass(|| Box::new(inline_fn_without_body::InlineFnWithoutBody));
-    store.register_late_pass(|| Box::new(useless_conversion::UselessConversion::default()));
-    store.register_late_pass(|| Box::new(implicit_hasher::ImplicitHasher));
-    store.register_late_pass(|| Box::new(fallible_impl_from::FallibleImplFrom));
-    store.register_late_pass(|| Box::new(question_mark::QuestionMark));
+    store.register_late_pass(move |_| Box::new(pass_by_ref_or_value));
+    store.register_late_pass(|_| Box::new(ref_option_ref::RefOptionRef));
+    store.register_late_pass(|_| Box::new(infinite_iter::InfiniteIter));
+    store.register_late_pass(|_| Box::new(inline_fn_without_body::InlineFnWithoutBody));
+    store.register_late_pass(|_| Box::new(useless_conversion::UselessConversion::default()));
+    store.register_late_pass(|_| Box::new(implicit_hasher::ImplicitHasher));
+    store.register_late_pass(|_| Box::new(fallible_impl_from::FallibleImplFrom));
+    store.register_late_pass(|_| Box::new(question_mark::QuestionMark));
     store.register_early_pass(|| Box::new(suspicious_operation_groupings::SuspiciousOperationGroupings));
-    store.register_late_pass(|| Box::new(suspicious_trait_impl::SuspiciousImpl));
-    store.register_late_pass(|| Box::new(map_unit_fn::MapUnit));
-    store.register_late_pass(|| Box::new(inherent_impl::MultipleInherentImpl));
-    store.register_late_pass(|| Box::new(neg_cmp_op_on_partial_ord::NoNegCompOpForPartialOrd));
-    store.register_late_pass(|| Box::new(unwrap::Unwrap));
-    store.register_late_pass(|| Box::new(indexing_slicing::IndexingSlicing));
-    store.register_late_pass(|| Box::new(non_copy_const::NonCopyConst));
-    store.register_late_pass(|| Box::new(ptr_offset_with_cast::PtrOffsetWithCast));
-    store.register_late_pass(|| Box::new(redundant_clone::RedundantClone));
-    store.register_late_pass(|| Box::new(slow_vector_initialization::SlowVectorInit));
-    store.register_late_pass(|| Box::new(unnecessary_sort_by::UnnecessarySortBy));
-    store.register_late_pass(move || Box::new(unnecessary_wraps::UnnecessaryWraps::new(avoid_breaking_exported_api)));
-    store.register_late_pass(|| Box::new(assertions_on_constants::AssertionsOnConstants));
-    store.register_late_pass(|| Box::new(assertions_on_result_states::AssertionsOnResultStates));
-    store.register_late_pass(|| Box::new(transmuting_null::TransmutingNull));
-    store.register_late_pass(|| Box::new(path_buf_push_overwrite::PathBufPushOverwrite));
-    store.register_late_pass(|| Box::new(inherent_to_string::InherentToString));
+    store.register_late_pass(|_| Box::new(suspicious_trait_impl::SuspiciousImpl));
+    store.register_late_pass(|_| Box::new(map_unit_fn::MapUnit));
+    store.register_late_pass(|_| Box::new(inherent_impl::MultipleInherentImpl));
+    store.register_late_pass(|_| Box::new(neg_cmp_op_on_partial_ord::NoNegCompOpForPartialOrd));
+    store.register_late_pass(|_| Box::new(unwrap::Unwrap));
+    store.register_late_pass(|_| Box::new(indexing_slicing::IndexingSlicing));
+    store.register_late_pass(|_| Box::new(non_copy_const::NonCopyConst));
+    store.register_late_pass(|_| Box::new(ptr_offset_with_cast::PtrOffsetWithCast));
+    store.register_late_pass(|_| Box::new(redundant_clone::RedundantClone));
+    store.register_late_pass(|_| Box::new(slow_vector_initialization::SlowVectorInit));
+    store.register_late_pass(move |_| Box::new(unnecessary_wraps::UnnecessaryWraps::new(avoid_breaking_exported_api)));
+    store.register_late_pass(|_| Box::new(assertions_on_constants::AssertionsOnConstants));
+    store.register_late_pass(|_| Box::new(assertions_on_result_states::AssertionsOnResultStates));
+    store.register_late_pass(|_| Box::new(inherent_to_string::InherentToString));
     let max_trait_bounds = conf.max_trait_bounds;
-    store.register_late_pass(move || Box::new(trait_bounds::TraitBounds::new(max_trait_bounds)));
-    store.register_late_pass(|| Box::new(comparison_chain::ComparisonChain));
-    store.register_late_pass(|| Box::new(mut_key::MutableKeyType));
+    store.register_late_pass(move |_| Box::new(trait_bounds::TraitBounds::new(max_trait_bounds)));
+    store.register_late_pass(|_| Box::new(comparison_chain::ComparisonChain));
+    store.register_late_pass(|_| Box::new(mut_key::MutableKeyType));
     store.register_early_pass(|| Box::new(reference::DerefAddrOf));
     store.register_early_pass(|| Box::new(double_parens::DoubleParens));
-    store.register_late_pass(|| Box::new(format_impl::FormatImpl::new()));
+    store.register_late_pass(|_| Box::new(format_impl::FormatImpl::new()));
     store.register_early_pass(|| Box::new(unsafe_removed_from_name::UnsafeNameRemoval));
     store.register_early_pass(|| Box::new(else_if_without_else::ElseIfWithoutElse));
     store.register_early_pass(|| Box::new(int_plus_one::IntPlusOne));
     store.register_early_pass(|| Box::new(formatting::Formatting));
     store.register_early_pass(|| Box::new(misc_early::MiscEarlyLints));
     store.register_early_pass(|| Box::new(redundant_closure_call::RedundantClosureCall));
-    store.register_late_pass(|| Box::new(redundant_closure_call::RedundantClosureCall));
+    store.register_late_pass(|_| Box::new(redundant_closure_call::RedundantClosureCall));
     store.register_early_pass(|| Box::new(unused_unit::UnusedUnit));
-    store.register_late_pass(|| Box::new(returns::Return));
+    store.register_late_pass(|_| Box::new(returns::Return));
     store.register_early_pass(|| Box::new(collapsible_if::CollapsibleIf));
     store.register_early_pass(|| Box::new(items_after_statements::ItemsAfterStatements));
     store.register_early_pass(|| Box::new(precedence::Precedence));
-    store.register_late_pass(|| Box::new(needless_parens_on_range_literals::NeedlessParensOnRangeLiterals));
+    store.register_late_pass(|_| Box::new(needless_parens_on_range_literals::NeedlessParensOnRangeLiterals));
     store.register_early_pass(|| Box::new(needless_continue::NeedlessContinue));
     store.register_early_pass(|| Box::new(redundant_else::RedundantElse));
-    store.register_late_pass(|| Box::new(create_dir::CreateDir));
+    store.register_late_pass(|_| Box::new(create_dir::CreateDir));
     store.register_early_pass(|| Box::new(needless_arbitrary_self_type::NeedlessArbitrarySelfType));
     let literal_representation_lint_fraction_readability = conf.unreadable_literal_lint_fractions;
     store.register_early_pass(move || {
@@ -782,7 +761,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         ))
     });
     let enum_variant_name_threshold = conf.enum_variant_name_threshold;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(enum_variants::EnumVariantNames::new(
             enum_variant_name_threshold,
             avoid_breaking_exported_api,
@@ -790,23 +769,23 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     });
     store.register_early_pass(|| Box::new(tabs_in_doc_comments::TabsInDocComments));
     let upper_case_acronyms_aggressive = conf.upper_case_acronyms_aggressive;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(upper_case_acronyms::UpperCaseAcronyms::new(
             avoid_breaking_exported_api,
             upper_case_acronyms_aggressive,
         ))
     });
-    store.register_late_pass(|| Box::new(default::Default::default()));
-    store.register_late_pass(move || Box::new(unused_self::UnusedSelf::new(avoid_breaking_exported_api)));
-    store.register_late_pass(|| Box::new(mutable_debug_assertion::DebugAssertWithMutCall));
-    store.register_late_pass(|| Box::new(exit::Exit));
-    store.register_late_pass(|| Box::new(to_digit_is_some::ToDigitIsSome));
+    store.register_late_pass(|_| Box::new(default::Default::default()));
+    store.register_late_pass(move |_| Box::new(unused_self::UnusedSelf::new(avoid_breaking_exported_api)));
+    store.register_late_pass(|_| Box::new(mutable_debug_assertion::DebugAssertWithMutCall));
+    store.register_late_pass(|_| Box::new(exit::Exit));
+    store.register_late_pass(|_| Box::new(to_digit_is_some::ToDigitIsSome));
     let array_size_threshold = conf.array_size_threshold;
-    store.register_late_pass(move || Box::new(large_stack_arrays::LargeStackArrays::new(array_size_threshold)));
-    store.register_late_pass(move || Box::new(large_const_arrays::LargeConstArrays::new(array_size_threshold)));
-    store.register_late_pass(|| Box::new(floating_point_arithmetic::FloatingPointArithmetic));
+    store.register_late_pass(move |_| Box::new(large_stack_arrays::LargeStackArrays::new(array_size_threshold)));
+    store.register_late_pass(move |_| Box::new(large_const_arrays::LargeConstArrays::new(array_size_threshold)));
+    store.register_late_pass(|_| Box::new(floating_point_arithmetic::FloatingPointArithmetic));
     store.register_early_pass(|| Box::new(as_conversions::AsConversions));
-    store.register_late_pass(|| Box::new(let_underscore::LetUnderscore));
+    store.register_late_pass(|_| Box::new(let_underscore::LetUnderscore));
     store.register_early_pass(|| Box::new(single_component_path_imports::SingleComponentPathImports));
     let max_fn_params_bools = conf.max_fn_params_bools;
     let max_struct_bools = conf.max_struct_bools;
@@ -818,20 +797,17 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     });
     store.register_early_pass(|| Box::new(option_env_unwrap::OptionEnvUnwrap));
     let warn_on_all_wildcard_imports = conf.warn_on_all_wildcard_imports;
-    store.register_late_pass(move || Box::new(wildcard_imports::WildcardImports::new(warn_on_all_wildcard_imports)));
-    store.register_late_pass(|| Box::new(verbose_file_reads::VerboseFileReads));
-    store.register_late_pass(|| Box::new(redundant_pub_crate::RedundantPubCrate::default()));
-    store.register_late_pass(|| Box::new(unnamed_address::UnnamedAddress));
-    store.register_late_pass(|| Box::new(dereference::Dereferencing::default()));
-    store.register_late_pass(|| Box::new(option_if_let_else::OptionIfLetElse));
-    store.register_late_pass(|| Box::new(future_not_send::FutureNotSend));
-    store.register_late_pass(|| Box::new(if_let_mutex::IfLetMutex));
-    store.register_late_pass(|| Box::new(if_not_else::IfNotElse));
-    store.register_late_pass(|| Box::new(equatable_if_let::PatternEquality));
-    store.register_late_pass(|| Box::new(mut_mutex_lock::MutMutexLock));
-    store.register_late_pass(|| Box::new(manual_async_fn::ManualAsyncFn));
-    store.register_late_pass(|| Box::new(vec_resize_to_zero::VecResizeToZero));
-    store.register_late_pass(|| Box::new(panic_in_result_fn::PanicInResultFn));
+    store.register_late_pass(move |_| Box::new(wildcard_imports::WildcardImports::new(warn_on_all_wildcard_imports)));
+    store.register_late_pass(|_| Box::new(redundant_pub_crate::RedundantPubCrate::default()));
+    store.register_late_pass(|_| Box::new(unnamed_address::UnnamedAddress));
+    store.register_late_pass(move |_| Box::new(dereference::Dereferencing::new(msrv)));
+    store.register_late_pass(|_| Box::new(option_if_let_else::OptionIfLetElse));
+    store.register_late_pass(|_| Box::new(future_not_send::FutureNotSend));
+    store.register_late_pass(|_| Box::new(if_let_mutex::IfLetMutex));
+    store.register_late_pass(|_| Box::new(if_not_else::IfNotElse));
+    store.register_late_pass(|_| Box::new(equatable_if_let::PatternEquality));
+    store.register_late_pass(|_| Box::new(manual_async_fn::ManualAsyncFn));
+    store.register_late_pass(|_| Box::new(panic_in_result_fn::PanicInResultFn));
     let single_char_binding_names_threshold = conf.single_char_binding_names_threshold;
     store.register_early_pass(move || {
         Box::new(non_expressive_names::NonExpressiveNames {
@@ -840,100 +816,95 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     });
     let macro_matcher = conf.standard_macro_braces.iter().cloned().collect::<FxHashSet<_>>();
     store.register_early_pass(move || Box::new(nonstandard_macro_braces::MacroBraces::new(&macro_matcher)));
-    store.register_late_pass(|| Box::new(macro_use::MacroUseImports::default()));
-    store.register_late_pass(|| Box::new(pattern_type_mismatch::PatternTypeMismatch));
-    store.register_late_pass(|| Box::new(stable_sort_primitive::StableSortPrimitive));
-    store.register_late_pass(|| Box::new(repeat_once::RepeatOnce));
-    store.register_late_pass(|| Box::new(unwrap_in_result::UnwrapInResult));
-    store.register_late_pass(|| Box::new(manual_ok_or::ManualOkOr));
-    store.register_late_pass(|| Box::new(semicolon_if_nothing_returned::SemicolonIfNothingReturned));
-    store.register_late_pass(|| Box::new(async_yields_async::AsyncYieldsAsync));
+    store.register_late_pass(|_| Box::new(macro_use::MacroUseImports::default()));
+    store.register_late_pass(|_| Box::new(pattern_type_mismatch::PatternTypeMismatch));
+    store.register_late_pass(|_| Box::new(unwrap_in_result::UnwrapInResult));
+    store.register_late_pass(|_| Box::new(semicolon_if_nothing_returned::SemicolonIfNothingReturned));
+    store.register_late_pass(|_| Box::new(async_yields_async::AsyncYieldsAsync));
     let disallowed_methods = conf.disallowed_methods.clone();
-    store.register_late_pass(move || Box::new(disallowed_methods::DisallowedMethods::new(disallowed_methods.clone())));
+    store.register_late_pass(move |_| Box::new(disallowed_methods::DisallowedMethods::new(disallowed_methods.clone())));
     store.register_early_pass(|| Box::new(asm_syntax::InlineAsmX86AttSyntax));
     store.register_early_pass(|| Box::new(asm_syntax::InlineAsmX86IntelSyntax));
-    store.register_late_pass(|| Box::new(empty_drop::EmptyDrop));
-    store.register_late_pass(|| Box::new(strings::StrToString));
-    store.register_late_pass(|| Box::new(strings::StringToString));
-    store.register_late_pass(|| Box::new(zero_sized_map_values::ZeroSizedMapValues));
-    store.register_late_pass(|| Box::new(vec_init_then_push::VecInitThenPush::default()));
-    store.register_late_pass(|| {
-        Box::new(case_sensitive_file_extension_comparisons::CaseSensitiveFileExtensionComparisons)
-    });
-    store.register_late_pass(|| Box::new(redundant_slicing::RedundantSlicing));
-    store.register_late_pass(|| Box::new(from_str_radix_10::FromStrRadix10));
-    store.register_late_pass(move || Box::new(if_then_some_else_none::IfThenSomeElseNone::new(msrv)));
-    store.register_late_pass(|| Box::new(bool_assert_comparison::BoolAssertComparison));
+    store.register_late_pass(|_| Box::new(empty_drop::EmptyDrop));
+    store.register_late_pass(|_| Box::new(strings::StrToString));
+    store.register_late_pass(|_| Box::new(strings::StringToString));
+    store.register_late_pass(|_| Box::new(zero_sized_map_values::ZeroSizedMapValues));
+    store.register_late_pass(|_| Box::new(vec_init_then_push::VecInitThenPush::default()));
+    store.register_late_pass(|_| Box::new(redundant_slicing::RedundantSlicing));
+    store.register_late_pass(|_| Box::new(from_str_radix_10::FromStrRadix10));
+    store.register_late_pass(move |_| Box::new(if_then_some_else_none::IfThenSomeElseNone::new(msrv)));
+    store.register_late_pass(|_| Box::new(bool_assert_comparison::BoolAssertComparison));
     store.register_early_pass(move || Box::new(module_style::ModStyle));
-    store.register_late_pass(|| Box::new(unused_async::UnusedAsync));
+    store.register_late_pass(|_| Box::new(unused_async::UnusedAsync));
     let disallowed_types = conf.disallowed_types.clone();
-    store.register_late_pass(move || Box::new(disallowed_types::DisallowedTypes::new(disallowed_types.clone())));
+    store.register_late_pass(move |_| Box::new(disallowed_types::DisallowedTypes::new(disallowed_types.clone())));
     let import_renames = conf.enforced_import_renames.clone();
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(missing_enforced_import_rename::ImportRename::new(
             import_renames.clone(),
         ))
     });
     let scripts = conf.allowed_scripts.clone();
     store.register_early_pass(move || Box::new(disallowed_script_idents::DisallowedScriptIdents::new(&scripts)));
-    store.register_late_pass(|| Box::new(strlen_on_c_strings::StrlenOnCStrings));
-    store.register_late_pass(move || Box::new(self_named_constructors::SelfNamedConstructors));
-    store.register_late_pass(move || Box::new(iter_not_returning_iterator::IterNotReturningIterator));
-    store.register_late_pass(move || Box::new(manual_assert::ManualAssert));
+    store.register_late_pass(|_| Box::new(strlen_on_c_strings::StrlenOnCStrings));
+    store.register_late_pass(move |_| Box::new(self_named_constructors::SelfNamedConstructors));
+    store.register_late_pass(move |_| Box::new(iter_not_returning_iterator::IterNotReturningIterator));
+    store.register_late_pass(move |_| Box::new(manual_assert::ManualAssert));
     let enable_raw_pointer_heuristic_for_send = conf.enable_raw_pointer_heuristic_for_send;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(non_send_fields_in_send_ty::NonSendFieldInSendTy::new(
             enable_raw_pointer_heuristic_for_send,
         ))
     });
-    store.register_late_pass(move || Box::new(undocumented_unsafe_blocks::UndocumentedUnsafeBlocks));
-    store.register_late_pass(move || Box::new(format_args::FormatArgs));
-    store.register_late_pass(|| Box::new(trailing_empty_array::TrailingEmptyArray));
+    store.register_late_pass(move |_| Box::new(undocumented_unsafe_blocks::UndocumentedUnsafeBlocks));
+    store.register_late_pass(move |_| Box::new(format_args::FormatArgs));
+    store.register_late_pass(|_| Box::new(trailing_empty_array::TrailingEmptyArray));
     store.register_early_pass(|| Box::new(octal_escapes::OctalEscapes));
-    store.register_late_pass(|| Box::new(needless_late_init::NeedlessLateInit));
-    store.register_late_pass(|| Box::new(return_self_not_must_use::ReturnSelfNotMustUse));
-    store.register_late_pass(|| Box::new(init_numbered_fields::NumberedFields));
+    store.register_late_pass(|_| Box::new(needless_late_init::NeedlessLateInit));
+    store.register_late_pass(|_| Box::new(return_self_not_must_use::ReturnSelfNotMustUse));
+    store.register_late_pass(|_| Box::new(init_numbered_fields::NumberedFields));
     store.register_early_pass(|| Box::new(single_char_lifetime_names::SingleCharLifetimeNames));
-    store.register_late_pass(move || Box::new(borrow_as_ptr::BorrowAsPtr::new(msrv)));
-    store.register_late_pass(move || Box::new(manual_bits::ManualBits::new(msrv)));
-    store.register_late_pass(|| Box::new(default_union_representation::DefaultUnionRepresentation));
+    store.register_late_pass(move |_| Box::new(manual_bits::ManualBits::new(msrv)));
+    store.register_late_pass(|_| Box::new(default_union_representation::DefaultUnionRepresentation));
     store.register_early_pass(|| Box::new(doc_link_with_quotes::DocLinkWithQuotes));
-    store.register_late_pass(|| Box::new(only_used_in_recursion::OnlyUsedInRecursion));
+    store.register_late_pass(|_| Box::new(only_used_in_recursion::OnlyUsedInRecursion::default()));
     let allow_dbg_in_tests = conf.allow_dbg_in_tests;
-    store.register_late_pass(move || Box::new(dbg_macro::DbgMacro::new(allow_dbg_in_tests)));
+    store.register_late_pass(move |_| Box::new(dbg_macro::DbgMacro::new(allow_dbg_in_tests)));
     let cargo_ignore_publish = conf.cargo_ignore_publish;
-    store.register_late_pass(move || {
+    store.register_late_pass(move |_| {
         Box::new(cargo::Cargo {
             ignore_publish: cargo_ignore_publish,
         })
     });
+    store.register_late_pass(|_| Box::new(write::Write::default()));
     store.register_early_pass(|| Box::new(crate_in_macro_def::CrateInMacroDef));
     store.register_early_pass(|| Box::new(empty_structs_with_brackets::EmptyStructsWithBrackets));
-    store.register_late_pass(|| Box::new(unnecessary_owned_empty_strings::UnnecessaryOwnedEmptyStrings));
+    store.register_late_pass(|_| Box::new(unnecessary_owned_empty_strings::UnnecessaryOwnedEmptyStrings));
     store.register_early_pass(|| Box::new(pub_use::PubUse));
-    store.register_late_pass(|| Box::new(format_push_string::FormatPushString));
-    store.register_late_pass(|| Box::new(bytes_count_to_len::BytesCountToLen));
+    store.register_late_pass(|_| Box::new(format_push_string::FormatPushString));
     let max_include_file_size = conf.max_include_file_size;
-    store.register_late_pass(move || Box::new(large_include_file::LargeIncludeFile::new(max_include_file_size)));
-    store.register_late_pass(|| Box::new(strings::TrimSplitWhitespace));
-    store.register_late_pass(|| Box::new(rc_clone_in_vec_init::RcCloneInVecInit));
+    store.register_late_pass(move |_| Box::new(large_include_file::LargeIncludeFile::new(max_include_file_size)));
+    store.register_late_pass(|_| Box::new(strings::TrimSplitWhitespace));
+    store.register_late_pass(|_| Box::new(rc_clone_in_vec_init::RcCloneInVecInit));
     store.register_early_pass(|| Box::new(duplicate_mod::DuplicateMod::default()));
-    store.register_late_pass(|| Box::new(get_first::GetFirst));
     store.register_early_pass(|| Box::new(unused_rounding::UnusedRounding));
     store.register_early_pass(move || Box::new(almost_complete_letter_range::AlmostCompleteLetterRange::new(msrv)));
-    store.register_late_pass(|| Box::new(swap_ptr_to_ref::SwapPtrToRef));
-    store.register_late_pass(|| Box::new(mismatching_type_param_order::TypeParamMismatch));
-    store.register_late_pass(|| Box::new(as_underscore::AsUnderscore));
-    store.register_late_pass(|| Box::new(read_zero_byte_vec::ReadZeroByteVec));
-    store.register_late_pass(|| Box::new(default_instead_of_iter_empty::DefaultIterEmpty));
-    store.register_late_pass(move || Box::new(manual_rem_euclid::ManualRemEuclid::new(msrv)));
-    store.register_late_pass(move || Box::new(manual_retain::ManualRetain::new(msrv)));
+    store.register_late_pass(|_| Box::new(swap_ptr_to_ref::SwapPtrToRef));
+    store.register_late_pass(|_| Box::new(mismatching_type_param_order::TypeParamMismatch));
+    store.register_late_pass(|_| Box::new(read_zero_byte_vec::ReadZeroByteVec));
+    store.register_late_pass(|_| Box::new(default_instead_of_iter_empty::DefaultIterEmpty));
+    store.register_late_pass(move |_| Box::new(manual_rem_euclid::ManualRemEuclid::new(msrv)));
+    store.register_late_pass(move |_| Box::new(manual_retain::ManualRetain::new(msrv)));
     let verbose_bit_mask_threshold = conf.verbose_bit_mask_threshold;
-    store.register_late_pass(move || Box::new(operators::Operators::new(verbose_bit_mask_threshold)));
-    store.register_late_pass(|| Box::new(invalid_utf8_in_unchecked::InvalidUtf8InUnchecked));
-    store.register_late_pass(|| Box::new(std_instead_of_core::StdReexports::default()));
-    store.register_late_pass(|| Box::new(manual_instant_elapsed::ManualInstantElapsed));
-    store.register_late_pass(|| Box::new(partialeq_to_none::PartialeqToNone));
+    store.register_late_pass(move |_| Box::new(operators::Operators::new(verbose_bit_mask_threshold)));
+    store.register_late_pass(|_| Box::new(invalid_utf8_in_unchecked::InvalidUtf8InUnchecked));
+    store.register_late_pass(|_| Box::new(std_instead_of_core::StdReexports::default()));
+    store.register_late_pass(|_| Box::new(manual_instant_elapsed::ManualInstantElapsed));
+    store.register_late_pass(|_| Box::new(partialeq_to_none::PartialeqToNone));
+    store.register_late_pass(|_| Box::new(manual_string_new::ManualStringNew));
+    store.register_late_pass(|_| Box::new(unused_peekable::UnusedPeekable));
+    store.register_early_pass(|| Box::new(multi_assignments::MultiAssignments));
+    store.register_late_pass(|_| Box::new(bool_to_int_with_if::BoolToIntWithIf));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 
diff --git a/src/tools/clippy/clippy_lints/src/lifetimes.rs b/src/tools/clippy/clippy_lints/src/lifetimes.rs
index 573a7c016b8e..399a03187d99 100644
--- a/src/tools/clippy/clippy_lints/src/lifetimes.rs
+++ b/src/tools/clippy/clippy_lints/src/lifetimes.rs
@@ -10,7 +10,7 @@ use rustc_hir::FnRetTy::Return;
 use rustc_hir::{
     BareFnTy, BodyId, FnDecl, GenericArg, GenericBound, GenericParam, GenericParamKind, Generics, Impl, ImplItem,
     ImplItemKind, Item, ItemKind, LangItem, Lifetime, LifetimeName, ParamName, PolyTraitRef, PredicateOrigin,
-    TraitBoundModifier, TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
+    TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter as middle_nested_filter;
@@ -102,7 +102,7 @@ impl<'tcx> LateLintPass<'tcx> for Lifetimes {
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
         if let ImplItemKind::Fn(ref sig, id) = item.kind {
-            let report_extra_lifetimes = trait_ref_of_method(cx, item.def_id).is_none();
+            let report_extra_lifetimes = trait_ref_of_method(cx, item.def_id.def_id).is_none();
             check_fn_inner(
                 cx,
                 sig.decl,
@@ -422,7 +422,7 @@ impl<'a, 'tcx> Visitor<'tcx> for RefVisitor<'a, 'tcx> {
         self.record(&Some(*lifetime));
     }
 
-    fn visit_poly_trait_ref(&mut self, poly_tref: &'tcx PolyTraitRef<'tcx>, tbm: TraitBoundModifier) {
+    fn visit_poly_trait_ref(&mut self, poly_tref: &'tcx PolyTraitRef<'tcx>) {
         let trait_ref = &poly_tref.trait_ref;
         if CLOSURE_TRAIT_BOUNDS.iter().any(|&item| {
             self.cx
@@ -435,13 +435,13 @@ impl<'a, 'tcx> Visitor<'tcx> for RefVisitor<'a, 'tcx> {
             sub_visitor.visit_trait_ref(trait_ref);
             self.nested_elision_site_lts.append(&mut sub_visitor.all_lts());
         } else {
-            walk_poly_trait_ref(self, poly_tref, tbm);
+            walk_poly_trait_ref(self, poly_tref);
         }
     }
 
     fn visit_ty(&mut self, ty: &'tcx Ty<'_>) {
         match ty.kind {
-            TyKind::OpaqueDef(item, bounds) => {
+            TyKind::OpaqueDef(item, bounds, _) => {
                 let map = self.cx.tcx.hir();
                 let item = map.item(item);
                 let len = self.lts.len();
@@ -466,7 +466,7 @@ impl<'a, 'tcx> Visitor<'tcx> for RefVisitor<'a, 'tcx> {
                     self.unelided_trait_object_lifetime = true;
                 }
                 for bound in bounds {
-                    self.visit_poly_trait_ref(bound, TraitBoundModifier::None);
+                    self.visit_poly_trait_ref(bound);
                 }
             },
             _ => walk_ty(self, ty),
diff --git a/src/tools/clippy/clippy_lints/src/loops/manual_find.rs b/src/tools/clippy/clippy_lints/src/loops/manual_find.rs
index 215c83a7edf6..09b2376d5c04 100644
--- a/src/tools/clippy/clippy_lints/src/loops/manual_find.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/manual_find.rs
@@ -106,7 +106,7 @@ fn get_binding(pat: &Pat<'_>) -> Option<HirId> {
             hir_id = None;
             return;
         }
-        if let BindingAnnotation::Unannotated = annotation {
+        if let BindingAnnotation::NONE = annotation {
             hir_id = Some(id);
         }
     });
diff --git a/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs b/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs
index a65df48e413e..3fc569af89ec 100644
--- a/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs
@@ -119,7 +119,7 @@ fn build_manual_memcpy_suggestion<'tcx>(
 
     let print_limit = |end: &Expr<'_>, end_str: &str, base: &Expr<'_>, sugg: MinifyingSugg<'static>| {
         if_chain! {
-            if let ExprKind::MethodCall(method, [recv], _) = end.kind;
+            if let ExprKind::MethodCall(method, recv, [], _) = end.kind;
             if method.ident.name == sym::len;
             if path_to_local(recv) == path_to_local(base);
             then {
@@ -341,7 +341,7 @@ fn get_slice_like_element_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Opti
 
 fn fetch_cloned_expr<'tcx>(expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
     if_chain! {
-        if let ExprKind::MethodCall(method, [arg], _) = expr.kind;
+        if let ExprKind::MethodCall(method, arg, [], _) = expr.kind;
         if method.ident.name == sym::clone;
         then { arg } else { expr }
     }
diff --git a/src/tools/clippy/clippy_lints/src/loops/missing_spin_loop.rs b/src/tools/clippy/clippy_lints/src/loops/missing_spin_loop.rs
index 0696afa39225..8412875b11b7 100644
--- a/src/tools/clippy/clippy_lints/src/loops/missing_spin_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/missing_spin_loop.rs
@@ -33,7 +33,7 @@ fn unpack_cond<'tcx>(cond: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, cond: &'tcx Expr<'_>, body: &'tcx Expr<'_>) {
     if_chain! {
         if let ExprKind::Block(Block { stmts: [], expr: None, ..}, _) = body.kind;
-        if let ExprKind::MethodCall(method, [callee, ..], _) = unpack_cond(cond).kind;
+        if let ExprKind::MethodCall(method, callee, ..) = unpack_cond(cond).kind;
         if [sym::load, sym::compare_exchange, sym::compare_exchange_weak].contains(&method.ident.name);
         if let ty::Adt(def, _substs) = cx.typeck_results().expr_ty(callee).kind();
         if cx.tcx.is_diagnostic_item(sym::AtomicBool, def.did());
diff --git a/src/tools/clippy/clippy_lints/src/loops/mod.rs b/src/tools/clippy/clippy_lints/src/loops/mod.rs
index ed270bd490d7..74f3bda9f43e 100644
--- a/src/tools/clippy/clippy_lints/src/loops/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/mod.rs
@@ -742,7 +742,7 @@ fn check_for_loop<'tcx>(
 fn check_for_loop_arg(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>) {
     let mut next_loop_linted = false; // whether or not ITER_NEXT_LOOP lint was used
 
-    if let ExprKind::MethodCall(method, [self_arg], _) = arg.kind {
+    if let ExprKind::MethodCall(method, self_arg, [], _) = arg.kind {
         let method_name = method.ident.as_str();
         // check for looping over x.iter() or x.iter_mut(), could use &x or &mut x
         match method_name {
diff --git a/src/tools/clippy/clippy_lints/src/loops/mut_range_bound.rs b/src/tools/clippy/clippy_lints/src/loops/mut_range_bound.rs
index aedf3810b23e..be7f96e9bb07 100644
--- a/src/tools/clippy/clippy_lints/src/loops/mut_range_bound.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/mut_range_bound.rs
@@ -44,7 +44,7 @@ fn check_for_mutability(cx: &LateContext<'_>, bound: &Expr<'_>) -> Option<HirId>
     if_chain! {
         if let Some(hir_id) = path_to_local(bound);
         if let Node::Pat(pat) = cx.tcx.hir().get(hir_id);
-        if let PatKind::Binding(BindingAnnotation::Mutable, ..) = pat.kind;
+        if let PatKind::Binding(BindingAnnotation::MUT, ..) = pat.kind;
         then {
             return Some(hir_id);
         }
@@ -69,7 +69,7 @@ fn check_for_mutation<'tcx>(
         ExprUseVisitor::new(
             &mut delegate,
             &infcx,
-            body.hir_id.owner,
+            body.hir_id.owner.def_id,
             cx.param_env,
             cx.typeck_results(),
         )
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs b/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs
index ddaffc751880..6e6faa79adc9 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs
@@ -1,5 +1,6 @@
 use super::NEEDLESS_COLLECT;
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
+use clippy_utils::higher;
 use clippy_utils::source::{snippet, snippet_with_applicability};
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::is_type_diagnostic_item;
@@ -24,11 +25,11 @@ pub(super) fn check<'tcx>(expr: &'tcx Expr<'_>, cx: &LateContext<'tcx>) {
 }
 fn check_needless_collect_direct_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateContext<'tcx>) {
     if_chain! {
-        if let ExprKind::MethodCall(method, args, _) = expr.kind;
-        if let ExprKind::MethodCall(chain_method, _, _) = args[0].kind;
-        if chain_method.ident.name == sym!(collect) && is_trait_method(cx, &args[0], sym::Iterator);
+        if let ExprKind::MethodCall(method, receiver, args, _) = expr.kind;
+        if let ExprKind::MethodCall(chain_method, ..) = receiver.kind;
+        if chain_method.ident.name == sym!(collect) && is_trait_method(cx, receiver, sym::Iterator);
         then {
-            let ty = cx.typeck_results().expr_ty(&args[0]);
+            let ty = cx.typeck_results().expr_ty(receiver);
             let mut applicability = Applicability::MaybeIncorrect;
             let is_empty_sugg = "next().is_none()".to_string();
             let method_name = method.ident.name.as_str();
@@ -40,7 +41,7 @@ fn check_needless_collect_direct_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateCont
                     "len" => "count()".to_string(),
                     "is_empty" => is_empty_sugg,
                     "contains" => {
-                        let contains_arg = snippet_with_applicability(cx, args[1].span, "??", &mut applicability);
+                        let contains_arg = snippet_with_applicability(cx, args[0].span, "??", &mut applicability);
                         let (arg, pred) = contains_arg
                             .strip_prefix('&')
                             .map_or(("&x", &*contains_arg), |s| ("x", s));
@@ -79,7 +80,7 @@ fn check_needless_collect_indirect_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateCo
                 if let StmtKind::Local(local) = stmt.kind;
                 if let PatKind::Binding(_, id, ..) = local.pat.kind;
                 if let Some(init_expr) = local.init;
-                if let ExprKind::MethodCall(method_name, &[ref iter_source], ..) = init_expr.kind;
+                if let ExprKind::MethodCall(method_name, iter_source, [], ..) = init_expr.kind;
                 if method_name.ident.name == sym!(collect) && is_trait_method(cx, init_expr, sym::Iterator);
                 let ty = cx.typeck_results().expr_ty(init_expr);
                 if is_type_diagnostic_item(cx, ty, sym::Vec) ||
@@ -184,16 +185,25 @@ struct IterFunctionVisitor<'a, 'tcx> {
 impl<'tcx> Visitor<'tcx> for IterFunctionVisitor<'_, 'tcx> {
     fn visit_block(&mut self, block: &'tcx Block<'tcx>) {
         for (expr, hir_id) in block.stmts.iter().filter_map(get_expr_and_hir_id_from_stmt) {
+            if check_loop_kind(expr).is_some() {
+                continue;
+            }
             self.visit_block_expr(expr, hir_id);
         }
         if let Some(expr) = block.expr {
-            self.visit_block_expr(expr, None);
+            if let Some(loop_kind) = check_loop_kind(expr) {
+                if let LoopKind::Conditional(block_expr) = loop_kind {
+                    self.visit_block_expr(block_expr, None);
+                }
+            } else {
+                self.visit_block_expr(expr, None);
+            }
         }
     }
 
     fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
         // Check function calls on our collection
-        if let ExprKind::MethodCall(method_name, [recv, args @ ..], _) = &expr.kind {
+        if let ExprKind::MethodCall(method_name, recv, [args @ ..], _) = &expr.kind {
             if method_name.ident.name == sym!(collect) && is_trait_method(self.cx, expr, sym::Iterator) {
                 self.current_mutably_captured_ids = get_captured_ids(self.cx, self.cx.typeck_results().expr_ty(recv));
                 self.visit_expr(recv);
@@ -264,6 +274,28 @@ impl<'tcx> Visitor<'tcx> for IterFunctionVisitor<'_, 'tcx> {
     }
 }
 
+enum LoopKind<'tcx> {
+    Conditional(&'tcx Expr<'tcx>),
+    Loop,
+}
+
+fn check_loop_kind<'tcx>(expr: &Expr<'tcx>) -> Option<LoopKind<'tcx>> {
+    if let Some(higher::WhileLet { let_expr, .. }) = higher::WhileLet::hir(expr) {
+        return Some(LoopKind::Conditional(let_expr));
+    }
+    if let Some(higher::While { condition, .. }) = higher::While::hir(expr) {
+        return Some(LoopKind::Conditional(condition));
+    }
+    if let Some(higher::ForLoop { arg, .. }) = higher::ForLoop::hir(expr) {
+        return Some(LoopKind::Conditional(arg));
+    }
+    if let ExprKind::Loop { .. } = expr.kind {
+        return Some(LoopKind::Loop);
+    }
+
+    None
+}
+
 impl<'tcx> IterFunctionVisitor<'_, 'tcx> {
     fn visit_block_expr(&mut self, expr: &'tcx Expr<'tcx>, hir_id: Option<HirId>) {
         self.current_statement_hir_id = hir_id;
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
index 7ca4a7c4ebfc..8ab640051b63 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
@@ -188,7 +188,7 @@ pub(super) fn check<'tcx>(
 
 fn is_len_call(expr: &Expr<'_>, var: Symbol) -> bool {
     if_chain! {
-        if let ExprKind::MethodCall(method, [recv], _) = expr.kind;
+        if let ExprKind::MethodCall(method, recv, [], _) = expr.kind;
         if method.ident.name == sym::len;
         if let ExprKind::Path(QPath::Resolved(_, path)) = recv.kind;
         if path.segments.len() == 1;
@@ -301,7 +301,7 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
         if_chain! {
             // a range index op
-            if let ExprKind::MethodCall(meth, [args_0, args_1, ..], _) = &expr.kind;
+            if let ExprKind::MethodCall(meth, args_0, [args_1, ..], _) = &expr.kind;
             if (meth.ident.name == sym::index && match_trait_method(self.cx, expr, &paths::INDEX))
                 || (meth.ident.name == sym::index_mut && match_trait_method(self.cx, expr, &paths::INDEX_MUT));
             if !self.check(args_1, args_0, expr);
@@ -356,9 +356,12 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
                     self.visit_expr(expr);
                 }
             },
-            ExprKind::MethodCall(_, args, _) => {
+            ExprKind::MethodCall(_, receiver, args, _) => {
                 let def_id = self.cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
-                for (ty, expr) in iter::zip(self.cx.tcx.fn_sig(def_id).inputs().skip_binder(), args) {
+                for (ty, expr) in iter::zip(
+                    self.cx.tcx.fn_sig(def_id).inputs().skip_binder(),
+                    std::iter::once(receiver).chain(args.iter()),
+                ) {
                     self.prefer_mutable = false;
                     if let ty::Ref(_, _, mutbl) = *ty.kind() {
                         if mutbl == Mutability::Mut {
@@ -370,7 +373,7 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
             },
             ExprKind::Closure(&Closure { body, .. }) => {
                 let body = self.cx.tcx.hir().body(body);
-                self.visit_expr(&body.value);
+                self.visit_expr(body.value);
             },
             _ => walk_expr(self, expr),
         }
diff --git a/src/tools/clippy/clippy_lints/src/loops/never_loop.rs b/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
index 32de20f6531f..116e589cad6f 100644
--- a/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
@@ -120,8 +120,9 @@ fn never_loop_expr(expr: &Expr<'_>, main_loop_id: HirId) -> NeverLoopResult {
         | ExprKind::Repeat(e, _)
         | ExprKind::DropTemps(e) => never_loop_expr(e, main_loop_id),
         ExprKind::Let(let_expr) => never_loop_expr(let_expr.init, main_loop_id),
-        ExprKind::Array(es) | ExprKind::MethodCall(_, es, _) | ExprKind::Tup(es) => {
-            never_loop_expr_all(&mut es.iter(), main_loop_id)
+        ExprKind::Array(es) | ExprKind::Tup(es) => never_loop_expr_all(&mut es.iter(), main_loop_id),
+        ExprKind::MethodCall(_, receiver, es, _) => {
+            never_loop_expr_all(&mut std::iter::once(receiver).chain(es.iter()), main_loop_id)
         },
         ExprKind::Struct(_, fields, base) => {
             let fields = never_loop_expr_all(&mut fields.iter().map(|f| f.expr), main_loop_id);
@@ -178,9 +179,9 @@ fn never_loop_expr(expr: &Expr<'_>, main_loop_id: HirId) -> NeverLoopResult {
                 InlineAsmOperand::In { expr, .. } | InlineAsmOperand::InOut { expr, .. } => {
                     never_loop_expr(expr, main_loop_id)
                 },
-                InlineAsmOperand::Out { expr, .. } => never_loop_expr_all(&mut expr.iter(), main_loop_id),
+                InlineAsmOperand::Out { expr, .. } => never_loop_expr_all(&mut expr.iter().copied(), main_loop_id),
                 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
-                    never_loop_expr_all(&mut once(in_expr).chain(out_expr.iter()), main_loop_id)
+                    never_loop_expr_all(&mut once(*in_expr).chain(out_expr.iter().copied()), main_loop_id)
                 },
                 InlineAsmOperand::Const { .. }
                 | InlineAsmOperand::SymFn { .. }
diff --git a/src/tools/clippy/clippy_lints/src/loops/same_item_push.rs b/src/tools/clippy/clippy_lints/src/loops/same_item_push.rs
index 1439f1f4c75d..aeefe6e33fbe 100644
--- a/src/tools/clippy/clippy_lints/src/loops/same_item_push.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/same_item_push.rs
@@ -7,7 +7,7 @@ use if_chain::if_chain;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::{walk_expr, Visitor};
-use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, HirId, Node, Pat, PatKind, Stmt, StmtKind};
+use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, HirId, Mutability, Node, Pat, PatKind, Stmt, StmtKind};
 use rustc_lint::LateContext;
 use rustc_span::symbol::sym;
 use std::iter::Iterator;
@@ -65,7 +65,7 @@ pub(super) fn check<'tcx>(
                             if_chain! {
                                 if let Node::Pat(pat) = node;
                                 if let PatKind::Binding(bind_ann, ..) = pat.kind;
-                                if !matches!(bind_ann, BindingAnnotation::RefMut | BindingAnnotation::Mutable);
+                                if !matches!(bind_ann, BindingAnnotation(_, Mutability::Mut));
                                 let parent_node = cx.tcx.hir().get_parent_node(hir_id);
                                 if let Some(Node::Local(parent_let_expr)) = cx.tcx.hir().find(parent_node);
                                 if let Some(init) = parent_let_expr.init;
@@ -180,10 +180,9 @@ fn get_vec_push<'tcx>(cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) -> Option<(&
     if_chain! {
             // Extract method being called
             if let StmtKind::Semi(semi_stmt) = &stmt.kind;
-            if let ExprKind::MethodCall(path, args, _) = &semi_stmt.kind;
+            if let ExprKind::MethodCall(path, self_expr, args, _) = &semi_stmt.kind;
             // Figure out the parameters for the method call
-            if let Some(self_expr) = args.get(0);
-            if let Some(pushed_item) = args.get(1);
+            if let Some(pushed_item) = args.get(0);
             // Check that the method being called is push() on a Vec
             if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(self_expr), sym::Vec);
             if path.ident.name.as_str() == "push";
diff --git a/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs b/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs
index a0bd7ad0ac64..f4b47808dfaa 100644
--- a/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs
@@ -35,32 +35,29 @@ pub(super) fn check<'tcx>(
         ) => (arg, "&mut "),
         ExprKind::MethodCall(
             method,
-            [
-                Expr {
-                    kind: ExprKind::Array([arg]),
-                    ..
-                },
-            ],
+            Expr {
+                kind: ExprKind::Array([arg]),
+                ..
+            },
+            [],
             _,
         ) if method.ident.name == rustc_span::sym::iter => (arg, "&"),
         ExprKind::MethodCall(
             method,
-            [
-                Expr {
-                    kind: ExprKind::Array([arg]),
-                    ..
-                },
-            ],
+            Expr {
+                kind: ExprKind::Array([arg]),
+                ..
+            },
+            [],
             _,
         ) if method.ident.name.as_str() == "iter_mut" => (arg, "&mut "),
         ExprKind::MethodCall(
             method,
-            [
-                Expr {
-                    kind: ExprKind::Array([arg]),
-                    ..
-                },
-            ],
+            Expr {
+                kind: ExprKind::Array([arg]),
+                ..
+            },
+            [],
             _,
         ) if method.ident.name == rustc_span::sym::into_iter => (arg, ""),
         // Only check for arrays edition 2021 or later, as this case will trigger a compiler error otherwise.
diff --git a/src/tools/clippy/clippy_lints/src/loops/while_let_loop.rs b/src/tools/clippy/clippy_lints/src/loops/while_let_loop.rs
index ca617859db49..735d704a43ce 100644
--- a/src/tools/clippy/clippy_lints/src/loops/while_let_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/while_let_loop.rs
@@ -11,7 +11,14 @@ use rustc_lint::LateContext;
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, loop_block: &'tcx Block<'_>) {
     let (init, has_trailing_exprs) = match (loop_block.stmts, loop_block.expr) {
         ([stmt, stmts @ ..], expr) => {
-            if let StmtKind::Local(&Local { init: Some(e), els: None, .. }) | StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind {
+            if let StmtKind::Local(&Local {
+                init: Some(e),
+                els: None,
+                ..
+            })
+            | StmtKind::Semi(e)
+            | StmtKind::Expr(e) = stmt.kind
+            {
                 (e, !stmts.is_empty() || expr.is_some())
             } else {
                 return;
diff --git a/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs b/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs
index e9e215e662f1..deb21894f36a 100644
--- a/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs
@@ -23,7 +23,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if let Res::Def(_, pat_did) = pat_path.res;
         if match_def_path(cx, pat_did, &paths::OPTION_SOME);
         // check for call to `Iterator::next`
-        if let ExprKind::MethodCall(method_name, [iter_expr], _) = let_expr.kind;
+        if let ExprKind::MethodCall(method_name, iter_expr, [], _) = let_expr.kind;
         if method_name.ident.name == sym::next;
         if is_trait_method(cx, let_expr, sym::Iterator);
         if let Some(iter_expr_struct) = try_parse_iter_expr(cx, iter_expr);
@@ -356,7 +356,7 @@ fn needs_mutable_borrow(cx: &LateContext<'_>, iter_expr: &IterExpr, loop_expr: &
             after_loop: false,
             used_iter: false,
         };
-        v.visit_expr(&cx.tcx.hir().body(cx.enclosing_body.unwrap()).value);
+        v.visit_expr(cx.tcx.hir().body(cx.enclosing_body.unwrap()).value);
         v.used_iter
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/manual_async_fn.rs b/src/tools/clippy/clippy_lints/src/manual_async_fn.rs
index a0ca7e6ff1e2..754b0e78a148 100644
--- a/src/tools/clippy/clippy_lints/src/manual_async_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_async_fn.rs
@@ -103,7 +103,7 @@ fn future_trait_ref<'tcx>(
     ty: &'tcx Ty<'tcx>,
 ) -> Option<(&'tcx TraitRef<'tcx>, Vec<LifetimeName>)> {
     if_chain! {
-        if let TyKind::OpaqueDef(item_id, bounds) = ty.kind;
+        if let TyKind::OpaqueDef(item_id, bounds, false) = ty.kind;
         let item = cx.tcx.hir().item(item_id);
         if let ItemKind::OpaqueTy(opaque) = &item.kind;
         if let Some(trait_ref) = opaque.bounds.iter().find_map(|bound| {
@@ -192,7 +192,7 @@ fn suggested_ret(cx: &LateContext<'_>, output: &Ty<'_>) -> Option<(&'static str,
     match output.kind {
         TyKind::Tup(tys) if tys.is_empty() => {
             let sugg = "remove the return type";
-            Some((sugg, "".into()))
+            Some((sugg, String::new()))
         },
         _ => {
             let sugg = "return the output of the future directly";
diff --git a/src/tools/clippy/clippy_lints/src/manual_bits.rs b/src/tools/clippy/clippy_lints/src/manual_bits.rs
index 60bbcde4f1de..6655c92b1da8 100644
--- a/src/tools/clippy/clippy_lints/src/manual_bits.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_bits.rs
@@ -105,7 +105,7 @@ fn get_size_of_ty<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<
         if let Some(def_id) = cx.qpath_res(count_func_qpath, count_func.hir_id).opt_def_id();
         if cx.tcx.is_diagnostic_item(sym::mem_size_of, def_id);
         then {
-            cx.typeck_results().node_substs(count_func.hir_id).types().next().map(|resolved_ty| (real_ty, resolved_ty))
+            cx.typeck_results().node_substs(count_func.hir_id).types().next().map(|resolved_ty| (*real_ty, resolved_ty))
         } else {
             None
         }
@@ -134,7 +134,7 @@ fn create_sugg(cx: &LateContext<'_>, expr: &Expr<'_>, base_sugg: String) -> Stri
 fn is_ty_conversion(expr: &Expr<'_>) -> bool {
     if let ExprKind::Cast(..) = expr.kind {
         true
-    } else if let ExprKind::MethodCall(path, [_], _) = expr.kind
+    } else if let ExprKind::MethodCall(path, _, [], _) = expr.kind
         && path.ident.name == rustc_span::sym::try_into
     {
         // This is only called for `usize` which implements `TryInto`. Therefore,
diff --git a/src/tools/clippy/clippy_lints/src/manual_non_exhaustive.rs b/src/tools/clippy/clippy_lints/src/manual_non_exhaustive.rs
index 2b04475c7a9d..53e7565bd33f 100644
--- a/src/tools/clippy/clippy_lints/src/manual_non_exhaustive.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_non_exhaustive.rs
@@ -166,7 +166,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualNonExhaustiveEnum {
             if let Some((id, span)) = iter.next()
                 && iter.next().is_none()
             {
-                self.potential_enums.push((item.def_id, id, item.span, span));
+                self.potential_enums.push((item.def_id.def_id, id, item.span, span));
             }
         }
     }
diff --git a/src/tools/clippy/clippy_lints/src/manual_ok_or.rs b/src/tools/clippy/clippy_lints/src/manual_ok_or.rs
deleted file mode 100644
index cf5004399b88..000000000000
--- a/src/tools/clippy/clippy_lints/src/manual_ok_or.rs
+++ /dev/null
@@ -1,95 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::{indent_of, reindent_multiline, snippet_opt};
-use clippy_utils::ty::is_type_diagnostic_item;
-use clippy_utils::{is_lang_ctor, path_to_local_id};
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir::LangItem::{ResultErr, ResultOk};
-use rustc_hir::{Closure, Expr, ExprKind, PatKind};
-use rustc_lint::LintContext;
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::lint::in_external_macro;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::symbol::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    ///
-    /// Finds patterns that reimplement `Option::ok_or`.
-    ///
-    /// ### Why is this bad?
-    ///
-    /// Concise code helps focusing on behavior instead of boilerplate.
-    ///
-    /// ### Examples
-    /// ```rust
-    /// let foo: Option<i32> = None;
-    /// foo.map_or(Err("error"), |v| Ok(v));
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust
-    /// let foo: Option<i32> = None;
-    /// foo.ok_or("error");
-    /// ```
-    #[clippy::version = "1.49.0"]
-    pub MANUAL_OK_OR,
-    pedantic,
-    "finds patterns that can be encoded more concisely with `Option::ok_or`"
-}
-
-declare_lint_pass!(ManualOkOr => [MANUAL_OK_OR]);
-
-impl<'tcx> LateLintPass<'tcx> for ManualOkOr {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, scrutinee: &'tcx Expr<'tcx>) {
-        if in_external_macro(cx.sess(), scrutinee.span) {
-            return;
-        }
-
-        if_chain! {
-            if let ExprKind::MethodCall(method_segment, [receiver, or_expr, map_expr], _) = scrutinee.kind;
-            if method_segment.ident.name == sym!(map_or);
-            let ty = cx.typeck_results().expr_ty(receiver);
-            if is_type_diagnostic_item(cx, ty, sym::Option);
-            if is_ok_wrapping(cx, map_expr);
-            if let ExprKind::Call(Expr { kind: ExprKind::Path(err_path), .. }, &[ref err_arg]) = or_expr.kind;
-            if is_lang_ctor(cx, err_path, ResultErr);
-            if let Some(method_receiver_snippet) = snippet_opt(cx, receiver.span);
-            if let Some(err_arg_snippet) = snippet_opt(cx, err_arg.span);
-            if let Some(indent) = indent_of(cx, scrutinee.span);
-            then {
-                let reindented_err_arg_snippet =
-                    reindent_multiline(err_arg_snippet.into(), true, Some(indent + 4));
-                span_lint_and_sugg(
-                    cx,
-                    MANUAL_OK_OR,
-                    scrutinee.span,
-                    "this pattern reimplements `Option::ok_or`",
-                    "replace with",
-                    format!(
-                        "{}.ok_or({})",
-                        method_receiver_snippet,
-                        reindented_err_arg_snippet
-                    ),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
-    }
-}
-
-fn is_ok_wrapping(cx: &LateContext<'_>, map_expr: &Expr<'_>) -> bool {
-    if let ExprKind::Path(ref qpath) = map_expr.kind {
-        if is_lang_ctor(cx, qpath, ResultOk) {
-            return true;
-        }
-    }
-    if_chain! {
-        if let ExprKind::Closure(&Closure { body, .. }) = map_expr.kind;
-        let body = cx.tcx.hir().body(body);
-        if let PatKind::Binding(_, param_id, ..) = body.params[0].pat.kind;
-        if let ExprKind::Call(Expr { kind: ExprKind::Path(ok_path), .. }, &[ref ok_arg]) = body.value.kind;
-        if is_lang_ctor(cx, ok_path, ResultOk);
-        then { path_to_local_id(ok_arg, param_id) } else { false }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/manual_retain.rs b/src/tools/clippy/clippy_lints/src/manual_retain.rs
index 42d2577cc316..f28c37d3dca7 100644
--- a/src/tools/clippy/clippy_lints/src/manual_retain.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_retain.rs
@@ -66,9 +66,9 @@ impl<'tcx> LateLintPass<'tcx> for ManualRetain {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
         if let Some(parent_expr) = get_parent_expr(cx, expr)
             && let Assign(left_expr, collect_expr, _) = &parent_expr.kind
-            && let hir::ExprKind::MethodCall(seg, _, _) = &collect_expr.kind
+            && let hir::ExprKind::MethodCall(seg, ..) = &collect_expr.kind
             && seg.args.is_none()
-            && let hir::ExprKind::MethodCall(_, [target_expr], _) = &collect_expr.kind
+            && let hir::ExprKind::MethodCall(_, target_expr, [], _) = &collect_expr.kind
             && let Some(collect_def_id) = cx.typeck_results().type_dependent_def_id(collect_expr.hir_id)
             && match_def_path(cx, collect_def_id, &paths::CORE_ITER_COLLECT) {
             check_into_iter(cx, parent_expr, left_expr, target_expr, self.msrv);
@@ -87,10 +87,10 @@ fn check_into_iter(
     target_expr: &hir::Expr<'_>,
     msrv: Option<RustcVersion>,
 ) {
-    if let hir::ExprKind::MethodCall(_, [into_iter_expr, _], _) = &target_expr.kind
+    if let hir::ExprKind::MethodCall(_, into_iter_expr, [_], _) = &target_expr.kind
         && let Some(filter_def_id) = cx.typeck_results().type_dependent_def_id(target_expr.hir_id)
         && match_def_path(cx, filter_def_id, &paths::CORE_ITER_FILTER)
-        && let hir::ExprKind::MethodCall(_, [struct_expr], _) = &into_iter_expr.kind
+        && let hir::ExprKind::MethodCall(_, struct_expr, [], _) = &into_iter_expr.kind
         && let Some(into_iter_def_id) = cx.typeck_results().type_dependent_def_id(into_iter_expr.hir_id)
         && match_def_path(cx, into_iter_def_id, &paths::CORE_ITER_INTO_ITER)
         && match_acceptable_type(cx, left_expr, msrv)
@@ -106,14 +106,14 @@ fn check_iter(
     target_expr: &hir::Expr<'_>,
     msrv: Option<RustcVersion>,
 ) {
-    if let hir::ExprKind::MethodCall(_, [filter_expr], _) = &target_expr.kind
+    if let hir::ExprKind::MethodCall(_, filter_expr, [], _) = &target_expr.kind
         && let Some(copied_def_id) = cx.typeck_results().type_dependent_def_id(target_expr.hir_id)
         && (match_def_path(cx, copied_def_id, &paths::CORE_ITER_COPIED)
             || match_def_path(cx, copied_def_id, &paths::CORE_ITER_CLONED))
-        && let hir::ExprKind::MethodCall(_, [iter_expr, _], _) = &filter_expr.kind
+        && let hir::ExprKind::MethodCall(_, iter_expr, [_], _) = &filter_expr.kind
         && let Some(filter_def_id) = cx.typeck_results().type_dependent_def_id(filter_expr.hir_id)
         && match_def_path(cx, filter_def_id, &paths::CORE_ITER_FILTER)
-        && let hir::ExprKind::MethodCall(_, [struct_expr], _) = &iter_expr.kind
+        && let hir::ExprKind::MethodCall(_, struct_expr, [], _) = &iter_expr.kind
         && let Some(iter_expr_def_id) = cx.typeck_results().type_dependent_def_id(iter_expr.hir_id)
         && match_acceptable_def_path(cx, iter_expr_def_id)
         && match_acceptable_type(cx, left_expr, msrv)
@@ -130,13 +130,13 @@ fn check_to_owned(
     msrv: Option<RustcVersion>,
 ) {
     if meets_msrv(msrv,  msrvs::STRING_RETAIN)
-        && let hir::ExprKind::MethodCall(_, [filter_expr], _) = &target_expr.kind
+        && let hir::ExprKind::MethodCall(_, filter_expr, [], _) = &target_expr.kind
         && let Some(to_owned_def_id) = cx.typeck_results().type_dependent_def_id(target_expr.hir_id)
         && match_def_path(cx, to_owned_def_id, &paths::TO_OWNED_METHOD)
-        && let hir::ExprKind::MethodCall(_, [chars_expr, _], _) = &filter_expr.kind
+        && let hir::ExprKind::MethodCall(_, chars_expr, [_], _) = &filter_expr.kind
         && let Some(filter_def_id) = cx.typeck_results().type_dependent_def_id(filter_expr.hir_id)
         && match_def_path(cx, filter_def_id, &paths::CORE_ITER_FILTER)
-        && let hir::ExprKind::MethodCall(_, [str_expr], _) = &chars_expr.kind
+        && let hir::ExprKind::MethodCall(_, str_expr, [], _) = &chars_expr.kind
         && let Some(chars_expr_def_id) = cx.typeck_results().type_dependent_def_id(chars_expr.hir_id)
         && match_def_path(cx, chars_expr_def_id, &paths::STR_CHARS)
         && let ty = cx.typeck_results().expr_ty(str_expr).peel_refs()
@@ -147,7 +147,7 @@ fn check_to_owned(
 }
 
 fn suggest(cx: &LateContext<'_>, parent_expr: &hir::Expr<'_>, left_expr: &hir::Expr<'_>, filter_expr: &hir::Expr<'_>) {
-    if let hir::ExprKind::MethodCall(_, [_, closure], _) = filter_expr.kind
+    if let hir::ExprKind::MethodCall(_, _, [closure], _) = filter_expr.kind
         && let hir::ExprKind::Closure(&hir::Closure { body, ..}) = closure.kind
         && let filter_body = cx.tcx.hir().body(body)
         && let [filter_params] = filter_body.params
diff --git a/src/tools/clippy/clippy_lints/src/manual_string_new.rs b/src/tools/clippy/clippy_lints/src/manual_string_new.rs
new file mode 100644
index 000000000000..6acfb2ae3471
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/manual_string_new.rs
@@ -0,0 +1,135 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use rustc_ast::LitKind;
+use rustc_errors::Applicability::MachineApplicable;
+use rustc_hir::{Expr, ExprKind, PathSegment, QPath, TyKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::{sym, symbol, Span};
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Checks for usage of `""` to create a `String`, such as `"".to_string()`, `"".to_owned()`,
+    /// `String::from("")` and others.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Different ways of creating an empty string makes your code less standardized, which can
+    /// be confusing.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let a = "".to_string();
+    /// let b: String = "".into();
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// let a = String::new();
+    /// let b = String::new();
+    /// ```
+    #[clippy::version = "1.65.0"]
+    pub MANUAL_STRING_NEW,
+    pedantic,
+    "empty String is being created manually"
+}
+declare_lint_pass!(ManualStringNew => [MANUAL_STRING_NEW]);
+
+impl LateLintPass<'_> for ManualStringNew {
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
+        if expr.span.from_expansion() {
+            return;
+        }
+
+        let ty = cx.typeck_results().expr_ty(expr);
+        match ty.kind() {
+            ty::Adt(adt_def, _) if adt_def.is_struct() => {
+                if !cx.tcx.is_diagnostic_item(sym::String, adt_def.did()) {
+                    return;
+                }
+            },
+            _ => return,
+        }
+
+        match expr.kind {
+            ExprKind::Call(func, args) => {
+                parse_call(cx, expr.span, func, args);
+            },
+            ExprKind::MethodCall(path_segment, receiver, ..) => {
+                parse_method_call(cx, expr.span, path_segment, receiver);
+            },
+            _ => (),
+        }
+    }
+}
+
+/// Checks if an expression's kind corresponds to an empty &str.
+fn is_expr_kind_empty_str(expr_kind: &ExprKind<'_>) -> bool {
+    if  let ExprKind::Lit(lit) = expr_kind &&
+        let LitKind::Str(value, _) = lit.node &&
+        value == symbol::kw::Empty
+    {
+        return true;
+    }
+
+    false
+}
+
+fn warn_then_suggest(cx: &LateContext<'_>, span: Span) {
+    span_lint_and_sugg(
+        cx,
+        MANUAL_STRING_NEW,
+        span,
+        "empty String is being created manually",
+        "consider using",
+        "String::new()".into(),
+        MachineApplicable,
+    );
+}
+
+/// Tries to parse an expression as a method call, emitting the warning if necessary.
+fn parse_method_call(cx: &LateContext<'_>, span: Span, path_segment: &PathSegment<'_>, receiver: &Expr<'_>) {
+    let ident = path_segment.ident.as_str();
+    let method_arg_kind = &receiver.kind;
+    if ["to_string", "to_owned", "into"].contains(&ident) && is_expr_kind_empty_str(method_arg_kind) {
+        warn_then_suggest(cx, span);
+    } else if let ExprKind::Call(func, args) = method_arg_kind {
+        // If our first argument is a function call itself, it could be an `unwrap`-like function.
+        // E.g. String::try_from("hello").unwrap(), TryFrom::try_from("").expect("hello"), etc.
+        parse_call(cx, span, func, args);
+    }
+}
+
+/// Tries to parse an expression as a function call, emitting the warning if necessary.
+fn parse_call(cx: &LateContext<'_>, span: Span, func: &Expr<'_>, args: &[Expr<'_>]) {
+    if args.len() != 1 {
+        return;
+    }
+
+    let arg_kind = &args[0].kind;
+    if let ExprKind::Path(qpath) = &func.kind {
+        if let QPath::TypeRelative(_, _) = qpath {
+            // String::from(...) or String::try_from(...)
+            if  let QPath::TypeRelative(ty, path_seg) = qpath &&
+                [sym::from, sym::try_from].contains(&path_seg.ident.name) &&
+                let TyKind::Path(qpath) = &ty.kind &&
+                let QPath::Resolved(_, path) = qpath &&
+                let [path_seg] = path.segments &&
+                path_seg.ident.name == sym::String &&
+                is_expr_kind_empty_str(arg_kind)
+            {
+                warn_then_suggest(cx, span);
+            }
+        } else if let QPath::Resolved(_, path) = qpath {
+            // From::from(...) or TryFrom::try_from(...)
+            if  let [path_seg1, path_seg2] = path.segments &&
+                is_expr_kind_empty_str(arg_kind) && (
+                    (path_seg1.ident.name == sym::From && path_seg2.ident.name == sym::from) ||
+                    (path_seg1.ident.name == sym::TryFrom && path_seg2.ident.name == sym::try_from)
+                )
+            {
+                warn_then_suggest(cx, span);
+            }
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/manual_strip.rs b/src/tools/clippy/clippy_lints/src/manual_strip.rs
index dfb3efc4e28b..7941c8c9c7e3 100644
--- a/src/tools/clippy/clippy_lints/src/manual_strip.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_strip.rs
@@ -74,7 +74,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualStrip {
 
         if_chain! {
             if let Some(higher::If { cond, then, .. }) = higher::If::hir(expr);
-            if let ExprKind::MethodCall(_, [target_arg, pattern], _) = cond.kind;
+            if let ExprKind::MethodCall(_, target_arg, [pattern], _) = cond.kind;
             if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(cond.hir_id);
             if let ExprKind::Path(target_path) = &target_arg.kind;
             then {
@@ -132,7 +132,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualStrip {
 // Returns `Some(arg)` if `expr` matches `arg.len()` and `None` otherwise.
 fn len_arg<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
     if_chain! {
-        if let ExprKind::MethodCall(_, [arg], _) = expr.kind;
+        if let ExprKind::MethodCall(_, arg, [], _) = expr.kind;
         if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
         if match_def_path(cx, method_def_id, &paths::STR_LEN);
         then {
diff --git a/src/tools/clippy/clippy_lints/src/map_clone.rs b/src/tools/clippy/clippy_lints/src/map_clone.rs
deleted file mode 100644
index 95c312f1fe26..000000000000
--- a/src/tools/clippy/clippy_lints/src/map_clone.rs
+++ /dev/null
@@ -1,167 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::{is_copy, is_type_diagnostic_item};
-use clippy_utils::{is_trait_method, meets_msrv, msrvs, peel_blocks};
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir as hir;
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::mir::Mutability;
-use rustc_middle::ty;
-use rustc_middle::ty::adjustment::Adjust;
-use rustc_semver::RustcVersion;
-use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::symbol::Ident;
-use rustc_span::{sym, Span};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for usage of `map(|x| x.clone())` or
-    /// dereferencing closures for `Copy` types, on `Iterator` or `Option`,
-    /// and suggests `cloned()` or `copied()` instead
-    ///
-    /// ### Why is this bad?
-    /// Readability, this can be written more concisely
-    ///
-    /// ### Example
-    /// ```rust
-    /// let x = vec![42, 43];
-    /// let y = x.iter();
-    /// let z = y.map(|i| *i);
-    /// ```
-    ///
-    /// The correct use would be:
-    ///
-    /// ```rust
-    /// let x = vec![42, 43];
-    /// let y = x.iter();
-    /// let z = y.cloned();
-    /// ```
-    #[clippy::version = "pre 1.29.0"]
-    pub MAP_CLONE,
-    style,
-    "using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types"
-}
-
-pub struct MapClone {
-    msrv: Option<RustcVersion>,
-}
-
-impl_lint_pass!(MapClone => [MAP_CLONE]);
-
-impl MapClone {
-    pub fn new(msrv: Option<RustcVersion>) -> Self {
-        Self { msrv }
-    }
-}
-
-impl<'tcx> LateLintPass<'tcx> for MapClone {
-    fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) {
-        if e.span.from_expansion() {
-            return;
-        }
-
-        if_chain! {
-            if let hir::ExprKind::MethodCall(method, args, _) = e.kind;
-            if args.len() == 2;
-            if method.ident.name == sym::map;
-            let ty = cx.typeck_results().expr_ty(&args[0]);
-            if is_type_diagnostic_item(cx, ty, sym::Option) || is_trait_method(cx, e, sym::Iterator);
-            if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = args[1].kind;
-            then {
-                let closure_body = cx.tcx.hir().body(body);
-                let closure_expr = peel_blocks(&closure_body.value);
-                match closure_body.params[0].pat.kind {
-                    hir::PatKind::Ref(inner, hir::Mutability::Not) => if let hir::PatKind::Binding(
-                        hir::BindingAnnotation::Unannotated, .., name, None
-                    ) = inner.kind {
-                        if ident_eq(name, closure_expr) {
-                            self.lint_explicit_closure(cx, e.span, args[0].span, true);
-                        }
-                    },
-                    hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, .., name, None) => {
-                        match closure_expr.kind {
-                            hir::ExprKind::Unary(hir::UnOp::Deref, inner) => {
-                                if ident_eq(name, inner) {
-                                    if let ty::Ref(.., Mutability::Not) = cx.typeck_results().expr_ty(inner).kind() {
-                                        self.lint_explicit_closure(cx, e.span, args[0].span, true);
-                                    }
-                                }
-                            },
-                            hir::ExprKind::MethodCall(method, [obj], _) => if_chain! {
-                                if ident_eq(name, obj) && method.ident.name == sym::clone;
-                                if let Some(fn_id) = cx.typeck_results().type_dependent_def_id(closure_expr.hir_id);
-                                if let Some(trait_id) = cx.tcx.trait_of_item(fn_id);
-                                if cx.tcx.lang_items().clone_trait().map_or(false, |id| id == trait_id);
-                                // no autoderefs
-                                if !cx.typeck_results().expr_adjustments(obj).iter()
-                                    .any(|a| matches!(a.kind, Adjust::Deref(Some(..))));
-                                then {
-                                    let obj_ty = cx.typeck_results().expr_ty(obj);
-                                    if let ty::Ref(_, ty, mutability) = obj_ty.kind() {
-                                        if matches!(mutability, Mutability::Not) {
-                                            let copy = is_copy(cx, *ty);
-                                            self.lint_explicit_closure(cx, e.span, args[0].span, copy);
-                                        }
-                                    } else {
-                                        lint_needless_cloning(cx, e.span, args[0].span);
-                                    }
-                                }
-                            },
-                            _ => {},
-                        }
-                    },
-                    _ => {},
-                }
-            }
-        }
-    }
-
-    extract_msrv_attr!(LateContext);
-}
-
-fn ident_eq(name: Ident, path: &hir::Expr<'_>) -> bool {
-    if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = path.kind {
-        path.segments.len() == 1 && path.segments[0].ident == name
-    } else {
-        false
-    }
-}
-
-fn lint_needless_cloning(cx: &LateContext<'_>, root: Span, receiver: Span) {
-    span_lint_and_sugg(
-        cx,
-        MAP_CLONE,
-        root.trim_start(receiver).unwrap(),
-        "you are needlessly cloning iterator elements",
-        "remove the `map` call",
-        String::new(),
-        Applicability::MachineApplicable,
-    );
-}
-
-impl MapClone {
-    fn lint_explicit_closure(&self, cx: &LateContext<'_>, replace: Span, root: Span, is_copy: bool) {
-        let mut applicability = Applicability::MachineApplicable;
-
-        let (message, sugg_method) = if is_copy && meets_msrv(self.msrv, msrvs::ITERATOR_COPIED) {
-            ("you are using an explicit closure for copying elements", "copied")
-        } else {
-            ("you are using an explicit closure for cloning elements", "cloned")
-        };
-
-        span_lint_and_sugg(
-            cx,
-            MAP_CLONE,
-            replace,
-            message,
-            &format!("consider calling the dedicated `{}` method", sugg_method),
-            format!(
-                "{}.{}()",
-                snippet_with_applicability(cx, root, "..", &mut applicability),
-                sugg_method,
-            ),
-            applicability,
-        );
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/map_err_ignore.rs b/src/tools/clippy/clippy_lints/src/map_err_ignore.rs
deleted file mode 100644
index 1e542447c96e..000000000000
--- a/src/tools/clippy/clippy_lints/src/map_err_ignore.rs
+++ /dev/null
@@ -1,154 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_help;
-use rustc_hir::{CaptureBy, Closure, Expr, ExprKind, PatKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for instances of `map_err(|_| Some::Enum)`
-    ///
-    /// ### Why is this bad?
-    /// This `map_err` throws away the original error rather than allowing the enum to contain and report the cause of the error
-    ///
-    /// ### Example
-    /// Before:
-    /// ```rust
-    /// use std::fmt;
-    ///
-    /// #[derive(Debug)]
-    /// enum Error {
-    ///     Indivisible,
-    ///     Remainder(u8),
-    /// }
-    ///
-    /// impl fmt::Display for Error {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         match self {
-    ///             Error::Indivisible => write!(f, "could not divide input by three"),
-    ///             Error::Remainder(remainder) => write!(
-    ///                 f,
-    ///                 "input is not divisible by three, remainder = {}",
-    ///                 remainder
-    ///             ),
-    ///         }
-    ///     }
-    /// }
-    ///
-    /// impl std::error::Error for Error {}
-    ///
-    /// fn divisible_by_3(input: &str) -> Result<(), Error> {
-    ///     input
-    ///         .parse::<i32>()
-    ///         .map_err(|_| Error::Indivisible)
-    ///         .map(|v| v % 3)
-    ///         .and_then(|remainder| {
-    ///             if remainder == 0 {
-    ///                 Ok(())
-    ///             } else {
-    ///                 Err(Error::Remainder(remainder as u8))
-    ///             }
-    ///         })
-    /// }
-    ///  ```
-    ///
-    ///  After:
-    ///  ```rust
-    /// use std::{fmt, num::ParseIntError};
-    ///
-    /// #[derive(Debug)]
-    /// enum Error {
-    ///     Indivisible(ParseIntError),
-    ///     Remainder(u8),
-    /// }
-    ///
-    /// impl fmt::Display for Error {
-    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         match self {
-    ///             Error::Indivisible(_) => write!(f, "could not divide input by three"),
-    ///             Error::Remainder(remainder) => write!(
-    ///                 f,
-    ///                 "input is not divisible by three, remainder = {}",
-    ///                 remainder
-    ///             ),
-    ///         }
-    ///     }
-    /// }
-    ///
-    /// impl std::error::Error for Error {
-    ///     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-    ///         match self {
-    ///             Error::Indivisible(source) => Some(source),
-    ///             _ => None,
-    ///         }
-    ///     }
-    /// }
-    ///
-    /// fn divisible_by_3(input: &str) -> Result<(), Error> {
-    ///     input
-    ///         .parse::<i32>()
-    ///         .map_err(Error::Indivisible)
-    ///         .map(|v| v % 3)
-    ///         .and_then(|remainder| {
-    ///             if remainder == 0 {
-    ///                 Ok(())
-    ///             } else {
-    ///                 Err(Error::Remainder(remainder as u8))
-    ///             }
-    ///         })
-    /// }
-    /// ```
-    #[clippy::version = "1.48.0"]
-    pub MAP_ERR_IGNORE,
-    restriction,
-    "`map_err` should not ignore the original error"
-}
-
-declare_lint_pass!(MapErrIgnore => [MAP_ERR_IGNORE]);
-
-impl<'tcx> LateLintPass<'tcx> for MapErrIgnore {
-    // do not try to lint if this is from a macro or desugaring
-    fn check_expr(&mut self, cx: &LateContext<'_>, e: &Expr<'_>) {
-        if e.span.from_expansion() {
-            return;
-        }
-
-        // check if this is a method call (e.g. x.foo())
-        if let ExprKind::MethodCall(method, [_, arg], _) = e.kind {
-            // only work if the method name is `map_err` and there are only 2 arguments (e.g. x.map_err(|_|[1]
-            // Enum::Variant[2]))
-            if method.ident.name == sym!(map_err) {
-                // make sure the first argument is a closure, and grab the CaptureRef, BodyId, and fn_decl_span
-                // fields
-                if let ExprKind::Closure(&Closure {
-                    capture_clause,
-                    body,
-                    fn_decl_span,
-                    ..
-                }) = arg.kind
-                {
-                    // check if this is by Reference (meaning there's no move statement)
-                    if capture_clause == CaptureBy::Ref {
-                        // Get the closure body to check the parameters and values
-                        let closure_body = cx.tcx.hir().body(body);
-                        // make sure there's only one parameter (`|_|`)
-                        if closure_body.params.len() == 1 {
-                            // make sure that parameter is the wild token (`_`)
-                            if let PatKind::Wild = closure_body.params[0].pat.kind {
-                                // span the area of the closure capture and warn that the
-                                // original error will be thrown away
-                                span_lint_and_help(
-                                    cx,
-                                    MAP_ERR_IGNORE,
-                                    fn_decl_span,
-                                    "`map_err(|_|...` wildcard pattern discards the original error",
-                                    None,
-                                    "consider storing the original error as a source in the new error, or silence this warning using an ignored identifier (`.map_err(|_foo| ...`)",
-                                );
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/map_unit_fn.rs b/src/tools/clippy/clippy_lints/src/map_unit_fn.rs
index 6db852c3ffe7..33d744815299 100644
--- a/src/tools/clippy/clippy_lints/src/map_unit_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/map_unit_fn.rs
@@ -200,8 +200,13 @@ fn suggestion_msg(function_type: &str, map_type: &str) -> String {
     )
 }
 
-fn lint_map_unit_fn(cx: &LateContext<'_>, stmt: &hir::Stmt<'_>, expr: &hir::Expr<'_>, map_args: &[hir::Expr<'_>]) {
-    let var_arg = &map_args[0];
+fn lint_map_unit_fn(
+    cx: &LateContext<'_>,
+    stmt: &hir::Stmt<'_>,
+    expr: &hir::Expr<'_>,
+    map_args: (&hir::Expr<'_>, &[hir::Expr<'_>]),
+) {
+    let var_arg = &map_args.0;
 
     let (map_type, variant, lint) = if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym::Option) {
         ("Option", "Some", OPTION_MAP_UNIT_FN)
@@ -210,7 +215,7 @@ fn lint_map_unit_fn(cx: &LateContext<'_>, stmt: &hir::Stmt<'_>, expr: &hir::Expr
     } else {
         return;
     };
-    let fn_arg = &map_args[1];
+    let fn_arg = &map_args.1[0];
 
     if is_unit_function(cx, fn_arg) {
         let mut applicability = Applicability::MachineApplicable;
diff --git a/src/tools/clippy/clippy_lints/src/match_result_ok.rs b/src/tools/clippy/clippy_lints/src/match_result_ok.rs
index 3349b85f1347..8588ab1ed8db 100644
--- a/src/tools/clippy/clippy_lints/src/match_result_ok.rs
+++ b/src/tools/clippy/clippy_lints/src/match_result_ok.rs
@@ -58,7 +58,7 @@ impl<'tcx> LateLintPass<'tcx> for MatchResultOk {
             };
 
         if_chain! {
-            if let ExprKind::MethodCall(ok_path, [ref result_types_0, ..], _) = let_expr.kind; //check is expr.ok() has type Result<T,E>.ok(, _)
+            if let ExprKind::MethodCall(ok_path, result_types_0, ..) = let_expr.kind; //check is expr.ok() has type Result<T,E>.ok(, _)
             if let PatKind::TupleStruct(QPath::Resolved(_, x), y, _)  = let_pat.kind; //get operation
             if method_chain_args(let_expr, &["ok"]).is_some(); //test to see if using ok() method use std::marker::Sized;
             if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(result_types_0), sym::Result);
diff --git a/src/tools/clippy/clippy_lints/src/matches/manual_map.rs b/src/tools/clippy/clippy_lints/src/matches/manual_map.rs
index 8f98b43b9e5c..b0198e856d5b 100644
--- a/src/tools/clippy/clippy_lints/src/matches/manual_map.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/manual_map.rs
@@ -165,7 +165,7 @@ fn check<'tcx>(
                 }
 
                 // `ref` and `ref mut` annotations were handled earlier.
-                let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
+                let annotation = if matches!(annotation, BindingAnnotation::MUT) {
                     "mut "
                 } else {
                     ""
diff --git a/src/tools/clippy/clippy_lints/src/matches/match_as_ref.rs b/src/tools/clippy/clippy_lints/src/matches/match_as_ref.rs
index a0efdecec67f..91d17f481e2d 100644
--- a/src/tools/clippy/clippy_lints/src/matches/match_as_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/match_as_ref.rs
@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::{is_lang_ctor, peel_blocks};
 use rustc_errors::Applicability;
-use rustc_hir::{Arm, BindingAnnotation, Expr, ExprKind, LangItem, PatKind, QPath};
+use rustc_hir::{Arm, BindingAnnotation, ByRef, Expr, ExprKind, LangItem, Mutability, PatKind, QPath};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 
@@ -10,18 +10,17 @@ use super::MATCH_AS_REF;
 
 pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
     if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
-        let arm_ref: Option<BindingAnnotation> = if is_none_arm(cx, &arms[0]) {
+        let arm_ref_mut = if is_none_arm(cx, &arms[0]) {
             is_ref_some_arm(cx, &arms[1])
         } else if is_none_arm(cx, &arms[1]) {
             is_ref_some_arm(cx, &arms[0])
         } else {
             None
         };
-        if let Some(rb) = arm_ref {
-            let suggestion = if rb == BindingAnnotation::Ref {
-                "as_ref"
-            } else {
-                "as_mut"
+        if let Some(rb) = arm_ref_mut {
+            let suggestion = match rb {
+                Mutability::Not => "as_ref",
+                Mutability::Mut => "as_mut",
             };
 
             let output_ty = cx.typeck_results().expr_ty(expr);
@@ -66,19 +65,18 @@ fn is_none_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
 }
 
 // Checks if arm has the form `Some(ref v) => Some(v)` (checks for `ref` and `ref mut`)
-fn is_ref_some_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> Option<BindingAnnotation> {
+fn is_ref_some_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> Option<Mutability> {
     if_chain! {
         if let PatKind::TupleStruct(ref qpath, [first_pat, ..], _) = arm.pat.kind;
         if is_lang_ctor(cx, qpath, LangItem::OptionSome);
-        if let PatKind::Binding(rb, .., ident, _) = first_pat.kind;
-        if rb == BindingAnnotation::Ref || rb == BindingAnnotation::RefMut;
+        if let PatKind::Binding(BindingAnnotation(ByRef::Yes, mutabl), .., ident, _) = first_pat.kind;
         if let ExprKind::Call(e, [arg]) = peel_blocks(arm.body).kind;
         if let ExprKind::Path(ref some_path) = e.kind;
         if is_lang_ctor(cx, some_path, LangItem::OptionSome);
         if let ExprKind::Path(QPath::Resolved(_, path2)) = arg.kind;
         if path2.segments.len() == 1 && ident.name == path2.segments[0].ident.name;
         then {
-            return Some(rb)
+            return Some(mutabl)
         }
     }
     None
diff --git a/src/tools/clippy/clippy_lints/src/matches/match_like_matches.rs b/src/tools/clippy/clippy_lints/src/matches/match_like_matches.rs
index 0da4833f1dfe..34cc082687ec 100644
--- a/src/tools/clippy/clippy_lints/src/matches/match_like_matches.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/match_like_matches.rs
@@ -1,10 +1,11 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::is_wild;
 use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::span_contains_comment;
 use rustc_ast::{Attribute, LitKind};
 use rustc_errors::Applicability;
 use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, Guard, Pat};
-use rustc_lint::LateContext;
+use rustc_lint::{LateContext, LintContext};
 use rustc_middle::ty;
 use rustc_span::source_map::Spanned;
 
@@ -76,6 +77,7 @@ where
         >,
 {
     if_chain! {
+        if !span_contains_comment(cx.sess().source_map(), expr.span);
         if iter.len() >= 2;
         if cx.typeck_results().expr_ty(expr).is_bool();
         if let Some((_, last_pat_opt, last_expr, _)) = iter.next_back();
diff --git a/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs b/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs
index e32ef9933afe..d37f44d4a17e 100644
--- a/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs
@@ -8,11 +8,10 @@ use rustc_arena::DroplessArena;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{Arm, Expr, ExprKind, HirId, HirIdMap, HirIdSet, Pat, PatKind, RangeEnd};
+use rustc_hir::{Arm, Expr, ExprKind, HirId, HirIdMap, HirIdMapEntry, HirIdSet, Pat, PatKind, RangeEnd};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 use rustc_span::Symbol;
-use std::collections::hash_map::Entry;
 
 use super::MATCH_SAME_ARMS;
 
@@ -71,9 +70,9 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>]) {
                 if let Some(a_id) = path_to_local(a);
                 if let Some(b_id) = path_to_local(b);
                 let entry = match local_map.entry(a_id) {
-                    Entry::Vacant(entry) => entry,
+                    HirIdMapEntry::Vacant(entry) => entry,
                     // check if using the same bindings as before
-                    Entry::Occupied(entry) => return *entry.get() == b_id,
+                    HirIdMapEntry::Occupied(entry) => return *entry.get() == b_id,
                 };
                 // the names technically don't have to match; this makes the lint more conservative
                 if cx.tcx.hir().name(a_id) == cx.tcx.hir().name(b_id);
@@ -248,7 +247,7 @@ impl<'a> NormalizedPat<'a> {
                 } else {
                     (None, adt.non_enum_variant())
                 };
-                let (front, back) = match wild_idx {
+                let (front, back) = match wild_idx.as_opt_usize() {
                     Some(i) => pats.split_at(i),
                     None => (pats, [].as_slice()),
                 };
@@ -268,7 +267,7 @@ impl<'a> NormalizedPat<'a> {
                     ty::Tuple(subs) => subs.len(),
                     _ => return Self::Wild,
                 };
-                let (front, back) = match wild_idx {
+                let (front, back) = match wild_idx.as_opt_usize() {
                     Some(i) => pats.split_at(i),
                     None => (pats, [].as_slice()),
                 };
diff --git a/src/tools/clippy/clippy_lints/src/matches/match_str_case_mismatch.rs b/src/tools/clippy/clippy_lints/src/matches/match_str_case_mismatch.rs
index fa3b8d1fceaa..1e80b6cf2d83 100644
--- a/src/tools/clippy/clippy_lints/src/matches/match_str_case_mismatch.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/match_str_case_mismatch.rs
@@ -48,7 +48,7 @@ struct MatchExprVisitor<'a, 'tcx> {
 impl<'a, 'tcx> Visitor<'tcx> for MatchExprVisitor<'a, 'tcx> {
     fn visit_expr(&mut self, ex: &'tcx Expr<'_>) {
         match ex.kind {
-            ExprKind::MethodCall(segment, [receiver], _) if self.case_altered(segment.ident.as_str(), receiver) => {},
+            ExprKind::MethodCall(segment, receiver, [], _) if self.case_altered(segment.ident.as_str(), receiver) => {},
             _ => walk_expr(self, ex),
         }
     }
diff --git a/src/tools/clippy/clippy_lints/src/matches/match_wild_err_arm.rs b/src/tools/clippy/clippy_lints/src/matches/match_wild_err_arm.rs
index bc16f17b6196..a3aa2e4b389a 100644
--- a/src/tools/clippy/clippy_lints/src/matches/match_wild_err_arm.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/match_wild_err_arm.rs
@@ -40,7 +40,7 @@ pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm<'
                                 arm.pat.span,
                                 &format!("`Err({})` matches all errors", ident_bind_name),
                                 None,
-                                "match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable",
+                                "match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable",
                             );
                         }
                     }
diff --git a/src/tools/clippy/clippy_lints/src/matches/needless_match.rs b/src/tools/clippy/clippy_lints/src/matches/needless_match.rs
index fa19cddd35ec..634eef82e532 100644
--- a/src/tools/clippy/clippy_lints/src/matches/needless_match.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/needless_match.rs
@@ -8,7 +8,7 @@ use clippy_utils::{
 };
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::OptionNone;
-use rustc_hir::{Arm, BindingAnnotation, Expr, ExprKind, FnRetTy, Node, Pat, PatKind, Path, QPath};
+use rustc_hir::{Arm, BindingAnnotation, ByRef, Expr, ExprKind, FnRetTy, Guard, Node, Pat, PatKind, Path, QPath};
 use rustc_lint::LateContext;
 use rustc_span::sym;
 use rustc_typeck::hir_ty_to_ty;
@@ -65,8 +65,26 @@ pub(crate) fn check_if_let<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'_>, if_let:
 fn check_all_arms(cx: &LateContext<'_>, match_expr: &Expr<'_>, arms: &[Arm<'_>]) -> bool {
     for arm in arms {
         let arm_expr = peel_blocks_with_stmt(arm.body);
+
+        if let Some(guard_expr) = &arm.guard {
+            match guard_expr {
+                // gives up if `pat if expr` can have side effects
+                Guard::If(if_cond) => {
+                    if if_cond.can_have_side_effects() {
+                        return false;
+                    }
+                },
+                // gives up `pat if let ...` arm
+                Guard::IfLet(_) => {
+                    return false;
+                },
+            };
+        }
+
         if let PatKind::Wild = arm.pat.kind {
-            return eq_expr_value(cx, match_expr, strip_return(arm_expr));
+            if !eq_expr_value(cx, match_expr, strip_return(arm_expr)) {
+                return false;
+            }
         } else if !pat_same_as_expr(arm.pat, arm_expr) {
             return false;
         }
@@ -171,8 +189,7 @@ fn pat_same_as_expr(pat: &Pat<'_>, expr: &Expr<'_>) -> bool {
                 },
             )),
         ) => {
-            return !matches!(annot, BindingAnnotation::Ref | BindingAnnotation::RefMut)
-                && pat_ident.name == first_seg.ident.name;
+            return !matches!(annot, BindingAnnotation(ByRef::Yes, _)) && pat_ident.name == first_seg.ident.name;
         },
         // Example: `Custom::TypeA => Custom::TypeB`, or `None => None`
         (PatKind::Path(QPath::Resolved(_, p_path)), ExprKind::Path(QPath::Resolved(_, e_path))) => {
diff --git a/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs b/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs
index 8499e050af24..c89784065b8b 100644
--- a/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/redundant_pattern_match.rs
@@ -2,17 +2,17 @@ use super::REDUNDANT_PATTERN_MATCHING;
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::source::snippet;
 use clippy_utils::sugg::Sugg;
-use clippy_utils::ty::needs_ordered_drop;
+use clippy_utils::ty::{is_type_diagnostic_item, needs_ordered_drop};
 use clippy_utils::visitors::any_temporaries_need_ordered_drop;
-use clippy_utils::{higher, is_lang_ctor, is_trait_method, match_def_path, paths};
+use clippy_utils::{higher, is_lang_ctor, is_trait_method};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::LangItem::{OptionNone, PollPending};
+use rustc_hir::LangItem::{self, OptionSome, OptionNone, PollPending, PollReady, ResultOk, ResultErr};
 use rustc_hir::{Arm, Expr, ExprKind, Node, Pat, PatKind, QPath, UnOp};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, subst::GenericArgKind, DefIdTree, Ty};
-use rustc_span::sym;
+use rustc_span::{sym, Symbol};
 
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
     if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
@@ -75,9 +75,9 @@ fn find_sugg_for_if_let<'tcx>(
                     ("is_some()", op_ty)
                 } else if Some(id) == lang_items.poll_ready_variant() {
                     ("is_ready()", op_ty)
-                } else if match_def_path(cx, id, &paths::IPADDR_V4) {
+                } else if is_pat_variant(cx, check_pat, qpath, Item::Diag(sym::IpAddr, sym!(V4))) {
                     ("is_ipv4()", op_ty)
-                } else if match_def_path(cx, id, &paths::IPADDR_V6) {
+                } else if is_pat_variant(cx, check_pat, qpath, Item::Diag(sym::IpAddr, sym!(V6))) {
                     ("is_ipv6()", op_ty)
                 } else {
                     return;
@@ -120,7 +120,7 @@ fn find_sugg_for_if_let<'tcx>(
     // check that `while_let_on_iterator` lint does not trigger
     if_chain! {
         if keyword == "while";
-        if let ExprKind::MethodCall(method_path, _, _) = let_expr.kind;
+        if let ExprKind::MethodCall(method_path, ..) = let_expr.kind;
         if method_path.ident.name == sym::next;
         if is_trait_method(cx, let_expr, sym::Iterator);
         then {
@@ -187,8 +187,8 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                         arms,
                         path_left,
                         path_right,
-                        &paths::RESULT_OK,
-                        &paths::RESULT_ERR,
+                        Item::Lang(ResultOk),
+                        Item::Lang(ResultErr),
                         "is_ok()",
                         "is_err()",
                     )
@@ -198,8 +198,8 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                             arms,
                             path_left,
                             path_right,
-                            &paths::IPADDR_V4,
-                            &paths::IPADDR_V6,
+                            Item::Diag(sym::IpAddr, sym!(V4)),
+                            Item::Diag(sym::IpAddr, sym!(V6)),
                             "is_ipv4()",
                             "is_ipv6()",
                         )
@@ -213,13 +213,14 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                 if patterns.len() == 1 =>
             {
                 if let PatKind::Wild = patterns[0].kind {
+
                     find_good_method_for_match(
                         cx,
                         arms,
                         path_left,
                         path_right,
-                        &paths::OPTION_SOME,
-                        &paths::OPTION_NONE,
+                        Item::Lang(OptionSome),
+                        Item::Lang(OptionNone),
                         "is_some()",
                         "is_none()",
                     )
@@ -229,8 +230,8 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
                             arms,
                             path_left,
                             path_right,
-                            &paths::POLL_READY,
-                            &paths::POLL_PENDING,
+                            Item::Lang(PollReady),
+                            Item::Lang(PollPending),
                             "is_ready()",
                             "is_pending()",
                         )
@@ -266,28 +267,61 @@ pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op
     }
 }
 
+#[derive(Clone, Copy)]
+enum Item {
+  Lang(LangItem),
+  Diag(Symbol, Symbol),
+}
+
+fn is_pat_variant(cx: &LateContext<'_>, pat: &Pat<'_>, path: &QPath<'_>, expected_item: Item) -> bool {
+    let Some(id) = cx.typeck_results().qpath_res(path, pat.hir_id).opt_def_id() else { return false };
+
+    match expected_item {
+        Item::Lang(expected_lang_item) => {
+            let expected_id = cx.tcx.lang_items().require(expected_lang_item).unwrap();
+            cx.tcx.parent(id) == expected_id
+        },
+        Item::Diag(expected_ty, expected_variant) => {
+            let ty = cx.typeck_results().pat_ty(pat);
+
+            if is_type_diagnostic_item(cx, ty, expected_ty) {
+                let variant = ty.ty_adt_def()
+                    .expect("struct pattern type is not an ADT")
+                    .variant_of_res(cx.qpath_res(path, pat.hir_id));
+
+                return variant.name == expected_variant
+            }
+
+            false
+        }
+    }
+}
+
 #[expect(clippy::too_many_arguments)]
 fn find_good_method_for_match<'a>(
     cx: &LateContext<'_>,
     arms: &[Arm<'_>],
     path_left: &QPath<'_>,
     path_right: &QPath<'_>,
-    expected_left: &[&str],
-    expected_right: &[&str],
+    expected_item_left: Item,
+    expected_item_right: Item,
     should_be_left: &'a str,
     should_be_right: &'a str,
 ) -> Option<&'a str> {
-    let left_id = cx
-        .typeck_results()
-        .qpath_res(path_left, arms[0].pat.hir_id)
-        .opt_def_id()?;
-    let right_id = cx
-        .typeck_results()
-        .qpath_res(path_right, arms[1].pat.hir_id)
-        .opt_def_id()?;
-    let body_node_pair = if match_def_path(cx, left_id, expected_left) && match_def_path(cx, right_id, expected_right) {
+    let pat_left = arms[0].pat;
+    let pat_right = arms[1].pat;
+
+    let body_node_pair = if (
+        is_pat_variant(cx, pat_left, path_left, expected_item_left)
+    ) && (
+        is_pat_variant(cx, pat_right, path_right, expected_item_right)
+    ) {
         (&arms[0].body.kind, &arms[1].body.kind)
-    } else if match_def_path(cx, right_id, expected_left) && match_def_path(cx, right_id, expected_right) {
+    } else if (
+        is_pat_variant(cx, pat_left, path_left, expected_item_right)
+    ) && (
+        is_pat_variant(cx, pat_right, path_right, expected_item_left)
+    ) {
         (&arms[1].body.kind, &arms[0].body.kind)
     } else {
         return None;
diff --git a/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs b/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs
index b0b15b3f54cd..86a9df034979 100644
--- a/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/significant_drop_in_scrutinee.rs
@@ -291,7 +291,7 @@ impl<'a, 'tcx> Visitor<'tcx> for SigDropHelper<'a, 'tcx> {
         self.is_chain_end = false;
 
         match ex.kind {
-            ExprKind::MethodCall(_, [ref expr, ..], _) => {
+            ExprKind::MethodCall(_, expr, ..) => {
                 self.visit_expr(expr);
             }
             ExprKind::Binary(_, left, right) => {
@@ -331,8 +331,7 @@ impl<'a, 'tcx> Visitor<'tcx> for SigDropHelper<'a, 'tcx> {
             ExprKind::Index(..) |
             ExprKind::Ret(..) |
             ExprKind::Repeat(..) |
-            ExprKind::Yield(..) |
-            ExprKind::MethodCall(..) => walk_expr(self, ex),
+            ExprKind::Yield(..) => walk_expr(self, ex),
             ExprKind::AddrOf(_, _, _) |
             ExprKind::Block(_, _) |
             ExprKind::Break(_, _) |
diff --git a/src/tools/clippy/clippy_lints/src/matches/single_match.rs b/src/tools/clippy/clippy_lints/src/matches/single_match.rs
index 92091a0c3395..56bcdc01fe4d 100644
--- a/src/tools/clippy/clippy_lints/src/matches/single_match.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/single_match.rs
@@ -175,7 +175,7 @@ fn collect_pat_paths<'a>(acc: &mut Vec<Ty<'a>>, cx: &LateContext<'a>, pat: &Pat<
             let p_ty = cx.typeck_results().pat_ty(p);
             collect_pat_paths(acc, cx, p, p_ty);
         }),
-        PatKind::TupleStruct(..) | PatKind::Binding(BindingAnnotation::Unannotated, .., None) | PatKind::Path(_) => {
+        PatKind::TupleStruct(..) | PatKind::Binding(BindingAnnotation::NONE, .., None) | PatKind::Path(_) => {
             acc.push(ty);
         },
         _ => {},
@@ -200,13 +200,11 @@ fn form_exhaustive_matches<'a>(cx: &LateContext<'a>, ty: Ty<'a>, left: &Pat<'_>,
             // We don't actually know the position and the presence of the `..` (dotdot) operator
             // in the arms, so we need to evaluate the correct offsets here in order to iterate in
             // both arms at the same time.
+            let left_pos = left_pos.as_opt_usize();
+            let right_pos = right_pos.as_opt_usize();
             let len = max(
-                left_in.len() + {
-                    if left_pos.is_some() { 1 } else { 0 }
-                },
-                right_in.len() + {
-                    if right_pos.is_some() { 1 } else { 0 }
-                },
+                left_in.len() + usize::from(left_pos.is_some()),
+                right_in.len() + usize::from(right_pos.is_some()),
             );
             let mut left_pos = left_pos.unwrap_or(usize::MAX);
             let mut right_pos = right_pos.unwrap_or(usize::MAX);
diff --git a/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs b/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
index 2f117e4dcc37..22f5635a5bcc 100644
--- a/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
@@ -152,7 +152,7 @@ pub(crate) trait BindInsteadOfMap {
         match arg.kind {
             hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }) => {
                 let closure_body = cx.tcx.hir().body(body);
-                let closure_expr = peel_blocks(&closure_body.value);
+                let closure_expr = peel_blocks(closure_body.value);
 
                 if Self::lint_closure_autofixable(cx, expr, recv, closure_expr, fn_decl_span) {
                     true
diff --git a/src/tools/clippy/clippy_lints/src/methods/bytecount.rs b/src/tools/clippy/clippy_lints/src/methods/bytecount.rs
new file mode 100644
index 000000000000..fef90f6eba49
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/bytecount.rs
@@ -0,0 +1,70 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::match_type;
+use clippy_utils::visitors::is_local_used;
+use clippy_utils::{path_to_local_id, paths, peel_blocks, peel_ref_operators, strip_pat_refs};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::{BinOpKind, Closure, Expr, ExprKind, PatKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self, UintTy};
+use rustc_span::sym;
+
+use super::NAIVE_BYTECOUNT;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    filter_recv: &'tcx Expr<'_>,
+    filter_arg: &'tcx Expr<'_>,
+) {
+    if_chain! {
+        if let ExprKind::Closure(&Closure { body, .. }) = filter_arg.kind;
+        let body = cx.tcx.hir().body(body);
+        if let [param] = body.params;
+        if let PatKind::Binding(_, arg_id, _, _) = strip_pat_refs(param.pat).kind;
+        if let ExprKind::Binary(ref op, l, r) = body.value.kind;
+        if op.node == BinOpKind::Eq;
+        if match_type(cx,
+                    cx.typeck_results().expr_ty(filter_recv).peel_refs(),
+                    &paths::SLICE_ITER);
+        let operand_is_arg = |expr| {
+            let expr = peel_ref_operators(cx, peel_blocks(expr));
+            path_to_local_id(expr, arg_id)
+        };
+        let needle = if operand_is_arg(l) {
+            r
+        } else if operand_is_arg(r) {
+            l
+        } else {
+            return;
+        };
+        if ty::Uint(UintTy::U8) == *cx.typeck_results().expr_ty(needle).peel_refs().kind();
+        if !is_local_used(cx, needle, arg_id);
+        then {
+            let haystack = if let ExprKind::MethodCall(path, receiver, [], _) =
+                    filter_recv.kind {
+                let p = path.ident.name;
+                if p == sym::iter || p == sym!(iter_mut) {
+                    receiver
+                } else {
+                    filter_recv
+                }
+            } else {
+                filter_recv
+            };
+            let mut applicability = Applicability::MaybeIncorrect;
+            span_lint_and_sugg(
+                cx,
+                NAIVE_BYTECOUNT,
+                expr.span,
+                "you appear to be counting bytes the naive way",
+                "consider using the bytecount crate",
+                format!("bytecount::count({}, {})",
+                        snippet_with_applicability(cx, haystack.span, "..", &mut applicability),
+                        snippet_with_applicability(cx, needle.span, "..", &mut applicability)),
+                applicability,
+            );
+        }
+    };
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/bytes_count_to_len.rs b/src/tools/clippy/clippy_lints/src/methods/bytes_count_to_len.rs
new file mode 100644
index 000000000000..fcfc25b523da
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/bytes_count_to_len.rs
@@ -0,0 +1,37 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::BYTES_COUNT_TO_LEN;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx hir::Expr<'_>,
+    count_recv: &'tcx hir::Expr<'_>,
+    bytes_recv: &'tcx hir::Expr<'_>,
+) {
+    if_chain! {
+        if let Some(bytes_id) = cx.typeck_results().type_dependent_def_id(count_recv.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(bytes_id);
+        if cx.tcx.type_of(impl_id).is_str();
+        let ty = cx.typeck_results().expr_ty(bytes_recv).peel_refs();
+        if ty.is_str() || is_type_diagnostic_item(cx, ty, sym::String);
+        then {
+            let mut applicability = Applicability::MachineApplicable;
+            span_lint_and_sugg(
+                cx,
+                BYTES_COUNT_TO_LEN,
+                expr.span,
+                "using long and hard to read `.bytes().count()`",
+                "consider calling `.len()` instead",
+                format!("{}.len()", snippet_with_applicability(cx, bytes_recv.span, "..", &mut applicability)),
+                applicability
+            );
+        }
+    };
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/case_sensitive_file_extension_comparisons.rs b/src/tools/clippy/clippy_lints/src/methods/case_sensitive_file_extension_comparisons.rs
new file mode 100644
index 000000000000..b3c2c7c9a2dc
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/case_sensitive_file_extension_comparisons.rs
@@ -0,0 +1,41 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::ast::LitKind;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::{source_map::Spanned, symbol::sym, Span};
+
+use super::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    call_span: Span,
+    recv: &'tcx Expr<'_>,
+    arg: &'tcx Expr<'_>,
+) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if cx.tcx.type_of(impl_id).is_str();
+        if let ExprKind::Lit(Spanned { node: LitKind::Str(ext_literal, ..), ..}) = arg.kind;
+        if (2..=6).contains(&ext_literal.as_str().len());
+        let ext_str = ext_literal.as_str();
+        if ext_str.starts_with('.');
+        if ext_str.chars().skip(1).all(|c| c.is_uppercase() || c.is_ascii_digit())
+            || ext_str.chars().skip(1).all(|c| c.is_lowercase() || c.is_ascii_digit());
+        let recv_ty = cx.typeck_results().expr_ty(recv).peel_refs();
+        if recv_ty.is_str() || is_type_diagnostic_item(cx, recv_ty, sym::String);
+        then {
+            span_lint_and_help(
+                cx,
+                CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
+                call_span,
+                "case-sensitive file extension comparison",
+                None,
+                "consider using a case-insensitive comparison instead",
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/chars_cmp.rs b/src/tools/clippy/clippy_lints/src/methods/chars_cmp.rs
index f7b79f0839ba..b2bc1ad5c9ed 100644
--- a/src/tools/clippy/clippy_lints/src/methods/chars_cmp.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/chars_cmp.rs
@@ -23,7 +23,7 @@ pub(super) fn check(
         if Some(id) == cx.tcx.lang_items().option_some_variant();
         then {
             let mut applicability = Applicability::MachineApplicable;
-            let self_ty = cx.typeck_results().expr_ty_adjusted(&args[0][0]).peel_refs();
+            let self_ty = cx.typeck_results().expr_ty_adjusted(args[0].0).peel_refs();
 
             if *self_ty.kind() != ty::Str {
                 return false;
@@ -37,7 +37,7 @@ pub(super) fn check(
                 "like this",
                 format!("{}{}.{}({})",
                         if info.eq { "" } else { "!" },
-                        snippet_with_applicability(cx, args[0][0].span, "..", &mut applicability),
+                        snippet_with_applicability(cx, args[0].0.span, "..", &mut applicability),
                         suggest,
                         snippet_with_applicability(cx, arg_char.span, "..", &mut applicability)),
                 applicability,
diff --git a/src/tools/clippy/clippy_lints/src/methods/chars_cmp_with_unwrap.rs b/src/tools/clippy/clippy_lints/src/methods/chars_cmp_with_unwrap.rs
index a7c0e43923e1..b85bfec2b12b 100644
--- a/src/tools/clippy/clippy_lints/src/methods/chars_cmp_with_unwrap.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/chars_cmp_with_unwrap.rs
@@ -30,7 +30,7 @@ pub(super) fn check<'tcx>(
                 "like this",
                 format!("{}{}.{}('{}')",
                         if info.eq { "" } else { "!" },
-                        snippet_with_applicability(cx, args[0][0].span, "..", &mut applicability),
+                        snippet_with_applicability(cx, args[0].0.span, "..", &mut applicability),
                         suggest,
                         c.escape_default()),
                 applicability,
diff --git a/src/tools/clippy/clippy_lints/src/methods/clone_on_copy.rs b/src/tools/clippy/clippy_lints/src/methods/clone_on_copy.rs
index 60e1355f9b92..7ab6b84c2074 100644
--- a/src/tools/clippy/clippy_lints/src/methods/clone_on_copy.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/clone_on_copy.rs
@@ -4,7 +4,7 @@ use clippy_utils::source::snippet_with_context;
 use clippy_utils::sugg;
 use clippy_utils::ty::is_copy;
 use rustc_errors::Applicability;
-use rustc_hir::{BindingAnnotation, Expr, ExprKind, MatchSource, Node, PatKind, QPath};
+use rustc_hir::{BindingAnnotation, ByRef, Expr, ExprKind, MatchSource, Node, PatKind, QPath};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, adjustment::Adjust};
 use rustc_span::symbol::{sym, Symbol};
@@ -14,10 +14,17 @@ use super::CLONE_ON_COPY;
 
 /// Checks for the `CLONE_ON_COPY` lint.
 #[allow(clippy::too_many_lines)]
-pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: Symbol, args: &[Expr<'_>]) {
-    let arg = match args {
-        [arg] if method_name == sym::clone => arg,
-        _ => return,
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    method_name: Symbol,
+    receiver: &Expr<'_>,
+    args: &[Expr<'_>],
+) {
+    let arg = if method_name == sym::clone && args.is_empty() {
+        receiver
+    } else {
+        return;
     };
     if cx
         .typeck_results()
@@ -81,7 +88,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: Symbol,
                 // &*x is a nop, &x.clone() is not
                 ExprKind::AddrOf(..) => return,
                 // (*x).func() is useless, x.clone().func() can work in case func borrows self
-                ExprKind::MethodCall(_, [self_arg, ..], _)
+                ExprKind::MethodCall(_, self_arg, ..)
                     if expr.hir_id == self_arg.hir_id && ty != cx.typeck_results().expr_ty_adjusted(expr) =>
                 {
                     return;
@@ -91,19 +98,14 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: Symbol,
                     hir_callee.kind,
                     ExprKind::Path(QPath::LangItem(rustc_hir::LangItem::TryTraitBranch, _, _))
                 ),
-                ExprKind::MethodCall(_, [self_arg, ..], _) if expr.hir_id == self_arg.hir_id => true,
+                ExprKind::MethodCall(_, self_arg, ..) if expr.hir_id == self_arg.hir_id => true,
                 ExprKind::Match(_, _, MatchSource::TryDesugar | MatchSource::AwaitDesugar)
                 | ExprKind::Field(..)
                 | ExprKind::Index(..) => true,
                 _ => false,
             },
             // local binding capturing a reference
-            Some(Node::Local(l))
-                if matches!(
-                    l.pat.kind,
-                    PatKind::Binding(BindingAnnotation::Ref | BindingAnnotation::RefMut, ..)
-                ) =>
-            {
+            Some(Node::Local(l)) if matches!(l.pat.kind, PatKind::Binding(BindingAnnotation(ByRef::Yes, _), ..)) => {
                 return;
             },
             _ => false,
diff --git a/src/tools/clippy/clippy_lints/src/methods/clone_on_ref_ptr.rs b/src/tools/clippy/clippy_lints/src/methods/clone_on_ref_ptr.rs
index 6417bc813047..f82ca8912006 100644
--- a/src/tools/clippy/clippy_lints/src/methods/clone_on_ref_ptr.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/clone_on_ref_ptr.rs
@@ -10,12 +10,17 @@ use rustc_span::symbol::{sym, Symbol};
 
 use super::CLONE_ON_REF_PTR;
 
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_name: Symbol, args: &[hir::Expr<'_>]) {
-    if !(args.len() == 1 && method_name == sym::clone) {
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &hir::Expr<'_>,
+    method_name: Symbol,
+    receiver: &hir::Expr<'_>,
+    args: &[hir::Expr<'_>],
+) {
+    if !(args.is_empty() && method_name == sym::clone) {
         return;
     }
-    let arg = &args[0];
-    let obj_ty = cx.typeck_results().expr_ty(arg).peel_refs();
+    let obj_ty = cx.typeck_results().expr_ty(receiver).peel_refs();
 
     if let ty::Adt(_, subst) = obj_ty.kind() {
         let caller_type = if is_type_diagnostic_item(cx, obj_ty, sym::Rc) {
@@ -28,7 +33,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_name: Sym
             return;
         };
 
-        let snippet = snippet_with_macro_callsite(cx, arg.span, "..");
+        let snippet = snippet_with_macro_callsite(cx, receiver.span, "..");
 
         span_lint_and_sugg(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/methods/collapsible_str_replace.rs b/src/tools/clippy/clippy_lints/src/methods/collapsible_str_replace.rs
new file mode 100644
index 000000000000..501646863fe1
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/collapsible_str_replace.rs
@@ -0,0 +1,96 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::visitors::for_each_expr;
+use clippy_utils::{eq_expr_value, get_parent_expr};
+use core::ops::ControlFlow;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use std::collections::VecDeque;
+
+use super::method_call;
+use super::COLLAPSIBLE_STR_REPLACE;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx hir::Expr<'tcx>,
+    from: &'tcx hir::Expr<'tcx>,
+    to: &'tcx hir::Expr<'tcx>,
+) {
+    let replace_methods = collect_replace_calls(cx, expr, to);
+    if replace_methods.methods.len() > 1 {
+        let from_kind = cx.typeck_results().expr_ty(from).peel_refs().kind();
+        // If the parent node's `to` argument is the same as the `to` argument
+        // of the last replace call in the current chain, don't lint as it was already linted
+        if let Some(parent) = get_parent_expr(cx, expr)
+            && let Some(("replace", _, [current_from, current_to], _)) = method_call(parent)
+            && eq_expr_value(cx, to, current_to)
+            && from_kind == cx.typeck_results().expr_ty(current_from).peel_refs().kind()
+        {
+            return;
+        }
+
+        check_consecutive_replace_calls(cx, expr, &replace_methods, to);
+    }
+}
+
+struct ReplaceMethods<'tcx> {
+    methods: VecDeque<&'tcx hir::Expr<'tcx>>,
+    from_args: VecDeque<&'tcx hir::Expr<'tcx>>,
+}
+
+fn collect_replace_calls<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx hir::Expr<'tcx>,
+    to_arg: &'tcx hir::Expr<'tcx>,
+) -> ReplaceMethods<'tcx> {
+    let mut methods = VecDeque::new();
+    let mut from_args = VecDeque::new();
+
+    let _: Option<()> = for_each_expr(expr, |e| {
+        if let Some(("replace", _, [from, to], _)) = method_call(e) {
+            if eq_expr_value(cx, to_arg, to) && cx.typeck_results().expr_ty(from).peel_refs().is_char() {
+                methods.push_front(e);
+                from_args.push_front(from);
+                ControlFlow::Continue(())
+            } else {
+                ControlFlow::BREAK
+            }
+        } else {
+            ControlFlow::Continue(())
+        }
+    });
+
+    ReplaceMethods { methods, from_args }
+}
+
+/// Check a chain of `str::replace` calls for `collapsible_str_replace` lint.
+fn check_consecutive_replace_calls<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx hir::Expr<'tcx>,
+    replace_methods: &ReplaceMethods<'tcx>,
+    to_arg: &'tcx hir::Expr<'tcx>,
+) {
+    let from_args = &replace_methods.from_args;
+    let from_arg_reprs: Vec<String> = from_args
+        .iter()
+        .map(|from_arg| snippet(cx, from_arg.span, "..").to_string())
+        .collect();
+    let app = Applicability::MachineApplicable;
+    let earliest_replace_call = replace_methods.methods.front().unwrap();
+    if let Some((_, _, [..], span_lo)) = method_call(earliest_replace_call) {
+        span_lint_and_sugg(
+            cx,
+            COLLAPSIBLE_STR_REPLACE,
+            expr.span.with_lo(span_lo.lo()),
+            "used consecutive `str::replace` call",
+            "replace with",
+            format!(
+                "replace([{}], {})",
+                from_arg_reprs.join(", "),
+                snippet(cx, to_arg.span, ".."),
+            ),
+            app,
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/err_expect.rs b/src/tools/clippy/clippy_lints/src/methods/err_expect.rs
index 570a1b87358d..720d9a68c85e 100644
--- a/src/tools/clippy/clippy_lints/src/methods/err_expect.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/err_expect.rs
@@ -1,6 +1,6 @@
 use super::ERR_EXPECT;
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::ty::implements_trait;
+use clippy_utils::ty::has_debug_impl;
 use clippy_utils::{meets_msrv, msrvs, ty::is_type_diagnostic_item};
 use rustc_errors::Applicability;
 use rustc_lint::LateContext;
@@ -28,7 +28,7 @@ pub(super) fn check(
         // Tests if the T type in a `Result<T, E>` is not None
         if let Some(data_type) = get_data_type(cx, result_type);
         // Tests if the T type in a `Result<T, E>` implements debug
-        if has_debug_impl(data_type, cx);
+        if has_debug_impl(cx, data_type);
 
         then {
             span_lint_and_sugg(
@@ -51,10 +51,3 @@ fn get_data_type<'a>(cx: &LateContext<'_>, ty: Ty<'a>) -> Option<Ty<'a>> {
         _ => None,
     }
 }
-
-/// Given a type, very if the Debug trait has been impl'd
-fn has_debug_impl<'tcx>(ty: Ty<'tcx>, cx: &LateContext<'tcx>) -> bool {
-    cx.tcx
-        .get_diagnostic_item(sym::Debug)
-        .map_or(false, |debug| implements_trait(cx, ty, debug, &[]))
-}
diff --git a/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs b/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs
index 6f2307d8f18f..bd846d71d466 100644
--- a/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs
@@ -19,6 +19,7 @@ pub(super) fn check<'tcx>(
     expr: &hir::Expr<'_>,
     method_span: Span,
     name: &str,
+    receiver: &'tcx hir::Expr<'tcx>,
     args: &'tcx [hir::Expr<'tcx>],
 ) {
     // Strip `&`, `as_ref()` and `as_str()` off `arg` until we're left with either a `String` or
@@ -28,16 +29,13 @@ pub(super) fn check<'tcx>(
         loop {
             arg_root = match &arg_root.kind {
                 hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => expr,
-                hir::ExprKind::MethodCall(method_name, call_args, _) => {
-                    if call_args.len() == 1
-                        && (method_name.ident.name == sym::as_str || method_name.ident.name == sym::as_ref)
-                        && {
-                            let arg_type = cx.typeck_results().expr_ty(&call_args[0]);
-                            let base_type = arg_type.peel_refs();
-                            *base_type.kind() == ty::Str || is_type_diagnostic_item(cx, base_type, sym::String)
-                        }
-                    {
-                        &call_args[0]
+                hir::ExprKind::MethodCall(method_name, receiver, [], ..) => {
+                    if (method_name.ident.name == sym::as_str || method_name.ident.name == sym::as_ref) && {
+                        let arg_type = cx.typeck_results().expr_ty(receiver);
+                        let base_type = arg_type.peel_refs();
+                        *base_type.kind() == ty::Str || is_type_diagnostic_item(cx, base_type, sym::String)
+                    } {
+                        receiver
                     } else {
                         break;
                     }
@@ -114,11 +112,11 @@ pub(super) fn check<'tcx>(
         }
     }
 
-    if args.len() != 2 || name != "expect" || !is_call(&args[1].kind) {
+    if args.len() != 1 || name != "expect" || !is_call(&args[0].kind) {
         return;
     }
 
-    let receiver_type = cx.typeck_results().expr_ty_adjusted(&args[0]);
+    let receiver_type = cx.typeck_results().expr_ty_adjusted(receiver);
     let closure_args = if is_type_diagnostic_item(cx, receiver_type, sym::Option) {
         "||"
     } else if is_type_diagnostic_item(cx, receiver_type, sym::Result) {
@@ -127,7 +125,7 @@ pub(super) fn check<'tcx>(
         return;
     };
 
-    let arg_root = get_arg_root(cx, &args[1]);
+    let arg_root = get_arg_root(cx, &args[0]);
 
     let span_replace_word = method_span.with_hi(expr.span.hi());
 
diff --git a/src/tools/clippy/clippy_lints/src/methods/expect_used.rs b/src/tools/clippy/clippy_lints/src/methods/expect_used.rs
index 5ef08ca6290b..d59fefa1ddc0 100644
--- a/src/tools/clippy/clippy_lints/src/methods/expect_used.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/expect_used.rs
@@ -7,18 +7,26 @@ use rustc_span::sym;
 
 use super::EXPECT_USED;
 
-/// lint use of `expect()` for `Option`s and `Result`s
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, allow_expect_in_tests: bool) {
+/// lint use of `expect()` or `expect_err` for `Result` and `expect()` for `Option`.
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &hir::Expr<'_>,
+    recv: &hir::Expr<'_>,
+    is_err: bool,
+    allow_expect_in_tests: bool,
+) {
     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
 
-    let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) {
+    let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) && !is_err {
         Some((EXPECT_USED, "an Option", "None", ""))
     } else if is_type_diagnostic_item(cx, obj_ty, sym::Result) {
-        Some((EXPECT_USED, "a Result", "Err", "an "))
+        Some((EXPECT_USED, "a Result", if is_err { "Ok" } else { "Err" }, "an "))
     } else {
         None
     };
 
+    let method = if is_err { "expect_err" } else { "expect" };
+
     if allow_expect_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
         return;
     }
@@ -28,7 +36,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
             cx,
             lint,
             expr.span,
-            &format!("used `expect()` on `{kind}` value"),
+            &format!("used `{method}()` on `{kind}` value"),
             None,
             &format!("if this value is {none_prefix}`{none_value}`, it will panic"),
         );
diff --git a/src/tools/clippy/clippy_lints/src/methods/extend_with_drain.rs b/src/tools/clippy/clippy_lints/src/methods/extend_with_drain.rs
index a15fe6094022..37b28463527c 100644
--- a/src/tools/clippy/clippy_lints/src/methods/extend_with_drain.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/extend_with_drain.rs
@@ -14,7 +14,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, arg:
     if_chain! {
         if is_type_diagnostic_item(cx, ty, sym::Vec);
         //check source object
-        if let ExprKind::MethodCall(src_method, [drain_vec, drain_arg], _) = &arg.kind;
+        if let ExprKind::MethodCall(src_method, drain_vec, [drain_arg], _) = &arg.kind;
         if src_method.ident.as_str() == "drain";
         let src_ty = cx.typeck_results().expr_ty(drain_vec);
         //check if actual src type is mutable for code suggestion
diff --git a/src/tools/clippy/clippy_lints/src/methods/filter_map.rs b/src/tools/clippy/clippy_lints/src/methods/filter_map.rs
index 692e22a7c5cf..9719b2f1c512 100644
--- a/src/tools/clippy/clippy_lints/src/methods/filter_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/filter_map.rs
@@ -25,14 +25,14 @@ fn is_method<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, method_name: Sy
         },
         hir::ExprKind::Closure(&hir::Closure { body, .. }) => {
             let body = cx.tcx.hir().body(body);
-            let closure_expr = peel_blocks(&body.value);
+            let closure_expr = peel_blocks(body.value);
             let arg_id = body.params[0].pat.hir_id;
             match closure_expr.kind {
-                hir::ExprKind::MethodCall(hir::PathSegment { ident, .. }, args, _) => {
+                hir::ExprKind::MethodCall(hir::PathSegment { ident, .. }, receiver, ..) => {
                     if_chain! {
                     if ident.name == method_name;
-                    if let hir::ExprKind::Path(path) = &args[0].kind;
-                    if let Res::Local(ref local) = cx.qpath_res(path, args[0].hir_id);
+                    if let hir::ExprKind::Path(path) = &receiver.kind;
+                    if let Res::Local(ref local) = cx.qpath_res(path, receiver.hir_id);
                     then {
                         return arg_id == *local
                     }
@@ -106,7 +106,7 @@ pub(super) fn check<'tcx>(
             };
             // closure ends with is_some() or is_ok()
             if let PatKind::Binding(_, filter_param_id, _, None) = filter_pat.kind;
-            if let ExprKind::MethodCall(path, [filter_arg], _) = filter_body.value.kind;
+            if let ExprKind::MethodCall(path, filter_arg, [], _) = filter_body.value.kind;
             if let Some(opt_ty) = cx.typeck_results().expr_ty(filter_arg).peel_refs().ty_adt_def();
             if let Some(is_result) = if cx.tcx.is_diagnostic_item(sym::Option, opt_ty.did()) {
                 Some(false)
@@ -123,13 +123,13 @@ pub(super) fn check<'tcx>(
             if let [map_param] = map_body.params;
             if let PatKind::Binding(_, map_param_id, map_param_ident, None) = map_param.pat.kind;
             // closure ends with expect() or unwrap()
-            if let ExprKind::MethodCall(seg, [map_arg, ..], _) = map_body.value.kind;
+            if let ExprKind::MethodCall(seg, map_arg, ..) = map_body.value.kind;
             if matches!(seg.ident.name, sym::expect | sym::unwrap | sym::unwrap_or);
 
             // .filter(..).map(|y| f(y).copied().unwrap())
             //                     ~~~~
             let map_arg_peeled = match map_arg.kind {
-                ExprKind::MethodCall(method, [original_arg], _) if acceptable_methods(method) => {
+                ExprKind::MethodCall(method, original_arg, [], _) if acceptable_methods(method) => {
                     original_arg
                 },
                 _ => map_arg,
diff --git a/src/tools/clippy/clippy_lints/src/methods/get_first.rs b/src/tools/clippy/clippy_lints/src/methods/get_first.rs
new file mode 100644
index 000000000000..4de77de74042
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/get_first.rs
@@ -0,0 +1,39 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_slice_of_primitives;
+use clippy_utils::source::snippet_with_applicability;
+use if_chain::if_chain;
+use rustc_ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use rustc_span::source_map::Spanned;
+
+use super::GET_FIRST;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx hir::Expr<'_>,
+    recv: &'tcx hir::Expr<'_>,
+    arg: &'tcx hir::Expr<'_>,
+) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if cx.tcx.type_of(impl_id).is_slice();
+        if let Some(_) = is_slice_of_primitives(cx, recv);
+        if let hir::ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = arg.kind;
+        then {
+            let mut app = Applicability::MachineApplicable;
+            let slice_name = snippet_with_applicability(cx, recv.span, "..", &mut app);
+            span_lint_and_sugg(
+                cx,
+                GET_FIRST,
+                expr.span,
+                &format!("accessing first element with `{0}.get(0)`", slice_name),
+                "try",
+                format!("{}.first()", slice_name),
+                app,
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/get_last_with_len.rs b/src/tools/clippy/clippy_lints/src/methods/get_last_with_len.rs
index 23368238ef5c..02aada87202c 100644
--- a/src/tools/clippy/clippy_lints/src/methods/get_last_with_len.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/get_last_with_len.rs
@@ -22,7 +22,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, arg:
     ) = arg.kind
 
         // LHS of subtraction is "x.len()"
-        && let ExprKind::MethodCall(lhs_path, [lhs_recv], _) = &lhs.kind
+        && let ExprKind::MethodCall(lhs_path, lhs_recv, [], _) = &lhs.kind
         && lhs_path.ident.name == sym::len
 
         // RHS of subtraction is 1
diff --git a/src/tools/clippy/clippy_lints/src/methods/inefficient_to_string.rs b/src/tools/clippy/clippy_lints/src/methods/inefficient_to_string.rs
index f52170df662c..e1c9b5248a8a 100644
--- a/src/tools/clippy/clippy_lints/src/methods/inefficient_to_string.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/inefficient_to_string.rs
@@ -12,13 +12,19 @@ use rustc_span::symbol::{sym, Symbol};
 use super::INEFFICIENT_TO_STRING;
 
 /// Checks for the `INEFFICIENT_TO_STRING` lint
-pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, method_name: Symbol, args: &[hir::Expr<'_>]) {
+pub fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &hir::Expr<'_>,
+    method_name: Symbol,
+    receiver: &hir::Expr<'_>,
+    args: &[hir::Expr<'_>],
+) {
     if_chain! {
-        if args.len() == 1 && method_name == sym::to_string;
+        if args.is_empty() && method_name == sym::to_string;
         if let Some(to_string_meth_did) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
         if match_def_path(cx, to_string_meth_did, &paths::TO_STRING_METHOD);
         if let Some(substs) = cx.typeck_results().node_substs_opt(expr.hir_id);
-        let arg_ty = cx.typeck_results().expr_ty_adjusted(&args[0]);
+        let arg_ty = cx.typeck_results().expr_ty_adjusted(receiver);
         let self_ty = substs.type_at(0);
         let (deref_self_ty, deref_count) = walk_ptrs_ty_depth(self_ty);
         if deref_count >= 1;
@@ -35,7 +41,7 @@ pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, method_name: Sy
                         self_ty, deref_self_ty
                     ));
                     let mut applicability = Applicability::MachineApplicable;
-                    let arg_snippet = snippet_with_applicability(cx, args[0].span, "..", &mut applicability);
+                    let arg_snippet = snippet_with_applicability(cx, receiver.span, "..", &mut applicability);
                     diag.span_suggestion(
                         expr.span,
                         "try dereferencing the receiver",
diff --git a/src/tools/clippy/clippy_lints/src/methods/into_iter_on_ref.rs b/src/tools/clippy/clippy_lints/src/methods/into_iter_on_ref.rs
index da13b4ba37a5..11e76841e9f0 100644
--- a/src/tools/clippy/clippy_lints/src/methods/into_iter_on_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/into_iter_on_ref.rs
@@ -16,9 +16,9 @@ pub(super) fn check(
     expr: &hir::Expr<'_>,
     method_span: Span,
     method_name: Symbol,
-    args: &[hir::Expr<'_>],
+    receiver: &hir::Expr<'_>,
 ) {
-    let self_ty = cx.typeck_results().expr_ty_adjusted(&args[0]);
+    let self_ty = cx.typeck_results().expr_ty_adjusted(receiver);
     if_chain! {
         if let ty::Ref(..) = self_ty.kind();
         if method_name == sym::into_iter;
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_kv_map.rs b/src/tools/clippy/clippy_lints/src/methods/iter_kv_map.rs
new file mode 100644
index 000000000000..a7eecabd6849
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_kv_map.rs
@@ -0,0 +1,87 @@
+#![allow(unused_imports)]
+
+use super::ITER_KV_MAP;
+use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::source::{snippet, snippet_with_applicability};
+use clippy_utils::sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::visitors::is_local_used;
+use rustc_hir::{BindingAnnotation, Body, BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind};
+use rustc_lint::{LateContext, LintContext};
+use rustc_middle::ty;
+use rustc_span::sym;
+use rustc_span::Span;
+
+/// lint use of:
+/// - `hashmap.iter().map(|(_, v)| v)`
+/// - `hashmap.into_iter().map(|(_, v)| v)`
+/// on `HashMaps` and `BTreeMaps` in std
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    map_type: &'tcx str,     // iter / into_iter
+    expr: &'tcx Expr<'tcx>,  // .iter().map(|(_, v_| v))
+    recv: &'tcx Expr<'tcx>,  // hashmap
+    m_arg: &'tcx Expr<'tcx>, // |(_, v)| v
+) {
+    if_chain! {
+        if !expr.span.from_expansion();
+        if let ExprKind::Closure(c) = m_arg.kind;
+        if let Body {params: [p], value: body_expr, generator_kind: _ } = cx.tcx.hir().body(c.body);
+        if let PatKind::Tuple([key_pat, val_pat], _) = p.pat.kind;
+
+        let (replacement_kind, binded_ident) = match (&key_pat.kind, &val_pat.kind) {
+            (key, PatKind::Binding(_, _, value, _)) if pat_is_wild(cx, key, m_arg) => ("value", value),
+            (PatKind::Binding(_, _, key, _), value) if pat_is_wild(cx, value, m_arg) => ("key", key),
+            _ => return,
+        };
+
+        let ty = cx.typeck_results().expr_ty(recv);
+        if is_type_diagnostic_item(cx, ty, sym::HashMap) || is_type_diagnostic_item(cx, ty, sym::BTreeMap);
+
+        then {
+            let mut applicability = rustc_errors::Applicability::MachineApplicable;
+            let recv_snippet = snippet_with_applicability(cx, recv.span, "map", &mut applicability);
+            let into_prefix = if map_type == "into_iter" {"into_"} else {""};
+
+            if_chain! {
+                if let ExprKind::Path(rustc_hir::QPath::Resolved(_, path)) = body_expr.kind;
+                if let [local_ident] = path.segments;
+                if local_ident.ident.as_str() == binded_ident.as_str();
+
+                then {
+                    span_lint_and_sugg(
+                        cx,
+                        ITER_KV_MAP,
+                        expr.span,
+                        &format!("iterating on a map's {}s", replacement_kind),
+                        "try",
+                        format!("{}.{}{}s()", recv_snippet, into_prefix, replacement_kind),
+                        applicability,
+                    );
+                } else {
+                    span_lint_and_sugg(
+                        cx,
+                        ITER_KV_MAP,
+                        expr.span,
+                        &format!("iterating on a map's {}s", replacement_kind),
+                        "try",
+                        format!("{}.{}{}s().map(|{}| {})", recv_snippet, into_prefix, replacement_kind, binded_ident,
+                            snippet_with_applicability(cx, body_expr.span, "/* body */", &mut applicability)),
+                        applicability,
+                    );
+                }
+            }
+        }
+    }
+}
+
+/// Returns `true` if the pattern is a `PatWild`, or is an ident prefixed with `_`
+/// that is not locally used.
+fn pat_is_wild<'tcx>(cx: &LateContext<'tcx>, pat: &'tcx PatKind<'_>, body: &'tcx Expr<'_>) -> bool {
+    match *pat {
+        PatKind::Wild => true,
+        PatKind::Binding(_, id, ident, None) if ident.as_str().starts_with('_') => !is_local_used(cx, body, id),
+        _ => false,
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs b/src/tools/clippy/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs
new file mode 100644
index 000000000000..cea7b0d82ff3
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_on_single_or_empty_collections.rs
@@ -0,0 +1,107 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::{get_expr_use_or_unification_node, is_lang_ctor, is_no_std_crate};
+
+use rustc_errors::Applicability;
+use rustc_hir::LangItem::{OptionNone, OptionSome};
+use rustc_hir::{Expr, ExprKind, Node};
+use rustc_lint::LateContext;
+
+use super::{ITER_ON_EMPTY_COLLECTIONS, ITER_ON_SINGLE_ITEMS};
+
+enum IterType {
+    Iter,
+    IterMut,
+    IntoIter,
+}
+
+impl IterType {
+    fn ref_prefix(&self) -> &'static str {
+        match self {
+            Self::Iter => "&",
+            Self::IterMut => "&mut ",
+            Self::IntoIter => "",
+        }
+    }
+}
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, method_name: &str, recv: &Expr<'_>) {
+    let item = match &recv.kind {
+        ExprKind::Array(v) if v.len() <= 1 => v.first(),
+        ExprKind::Path(p) => {
+            if is_lang_ctor(cx, p, OptionNone) {
+                None
+            } else {
+                return;
+            }
+        },
+        ExprKind::Call(f, some_args) if some_args.len() == 1 => {
+            if let ExprKind::Path(p) = &f.kind {
+                if is_lang_ctor(cx, p, OptionSome) {
+                    Some(&some_args[0])
+                } else {
+                    return;
+                }
+            } else {
+                return;
+            }
+        },
+        _ => return,
+    };
+    let iter_type = match method_name {
+        "iter" => IterType::Iter,
+        "iter_mut" => IterType::IterMut,
+        "into_iter" => IterType::IntoIter,
+        _ => return,
+    };
+
+    let is_unified = match get_expr_use_or_unification_node(cx.tcx, expr) {
+        Some((Node::Expr(parent), child_id)) => match parent.kind {
+            ExprKind::If(e, _, _) | ExprKind::Match(e, _, _) if e.hir_id == child_id => false,
+            ExprKind::If(_, _, _)
+            | ExprKind::Match(_, _, _)
+            | ExprKind::Closure(_)
+            | ExprKind::Ret(_)
+            | ExprKind::Break(_, _) => true,
+            _ => false,
+        },
+        Some((Node::Stmt(_) | Node::Local(_), _)) => false,
+        _ => true,
+    };
+
+    if is_unified {
+        return;
+    }
+
+    if let Some(i) = item {
+        let sugg = format!(
+            "{}::iter::once({}{})",
+            if is_no_std_crate(cx) { "core" } else { "std" },
+            iter_type.ref_prefix(),
+            snippet(cx, i.span, "...")
+        );
+        span_lint_and_sugg(
+            cx,
+            ITER_ON_SINGLE_ITEMS,
+            expr.span,
+            &format!("`{method_name}` call on a collection with only one item"),
+            "try",
+            sugg,
+            Applicability::MaybeIncorrect,
+        );
+    } else {
+        span_lint_and_sugg(
+            cx,
+            ITER_ON_EMPTY_COLLECTIONS,
+            expr.span,
+            &format!("`{method_name}` call on an empty collection"),
+            "try",
+            if is_no_std_crate(cx) {
+                "core::iter::empty()".to_string()
+            } else {
+                "std::iter::empty()".to_string()
+            },
+            Applicability::MaybeIncorrect,
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs b/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs
index 43e9451f7d37..beb772100aff 100644
--- a/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs
@@ -24,7 +24,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
                     if let Some(id) = path_to_local(recv);
                     if let Node::Pat(pat) = cx.tcx.hir().get(id);
                     if let PatKind::Binding(ann, _, _, _)  = pat.kind;
-                    if ann != BindingAnnotation::Mutable;
+                    if ann != BindingAnnotation::MUT;
                     then {
                         application = Applicability::Unspecified;
                         diag.span_help(
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_with_drain.rs b/src/tools/clippy/clippy_lints/src/methods/iter_with_drain.rs
index 152072e09c77..a669cbbbcc60 100644
--- a/src/tools/clippy/clippy_lints/src/methods/iter_with_drain.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_with_drain.rs
@@ -35,7 +35,7 @@ fn is_full_range(cx: &LateContext<'_>, container: &Expr<'_>, range: Range<'_>) -
         && range.end.map_or(true, |e| {
             if range.limits == RangeLimits::HalfOpen
                 && let ExprKind::Path(QPath::Resolved(None, container_path)) = container.kind
-                && let ExprKind::MethodCall(name, [self_arg], _) = e.kind
+                && let ExprKind::MethodCall(name, self_arg, [], _) = e.kind
                 && name.ident.name == sym::len
                 && let ExprKind::Path(QPath::Resolved(None, path)) = self_arg.kind
             {
diff --git a/src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs b/src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs
new file mode 100644
index 000000000000..ffd2f4a38b8a
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/manual_ok_or.rs
@@ -0,0 +1,64 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::{indent_of, reindent_multiline, snippet_opt};
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{is_lang_ctor, path_to_local_id};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::LangItem::{ResultErr, ResultOk};
+use rustc_hir::{Closure, Expr, ExprKind, PatKind};
+use rustc_lint::LateContext;
+use rustc_span::symbol::sym;
+
+use super::MANUAL_OK_OR;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'tcx>,
+    recv: &'tcx Expr<'_>,
+    or_expr: &'tcx Expr<'_>,
+    map_expr: &'tcx Expr<'_>,
+) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Option);
+        if let ExprKind::Call(Expr { kind: ExprKind::Path(err_path), .. }, [err_arg]) = or_expr.kind;
+        if is_lang_ctor(cx, err_path, ResultErr);
+        if is_ok_wrapping(cx, map_expr);
+        if let Some(recv_snippet) = snippet_opt(cx, recv.span);
+        if let Some(err_arg_snippet) = snippet_opt(cx, err_arg.span);
+        if let Some(indent) = indent_of(cx, expr.span);
+        then {
+            let reindented_err_arg_snippet = reindent_multiline(err_arg_snippet.into(), true, Some(indent + 4));
+            span_lint_and_sugg(
+                cx,
+                MANUAL_OK_OR,
+                expr.span,
+                "this pattern reimplements `Option::ok_or`",
+                "replace with",
+                format!(
+                    "{}.ok_or({})",
+                    recv_snippet,
+                    reindented_err_arg_snippet
+                ),
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+}
+
+fn is_ok_wrapping(cx: &LateContext<'_>, map_expr: &Expr<'_>) -> bool {
+    if let ExprKind::Path(ref qpath) = map_expr.kind {
+        if is_lang_ctor(cx, qpath, ResultOk) {
+            return true;
+        }
+    }
+    if_chain! {
+        if let ExprKind::Closure(&Closure { body, .. }) = map_expr.kind;
+        let body = cx.tcx.hir().body(body);
+        if let PatKind::Binding(_, param_id, ..) = body.params[0].pat.kind;
+        if let ExprKind::Call(Expr { kind: ExprKind::Path(ok_path), .. }, &[ref ok_arg]) = body.value.kind;
+        if is_lang_ctor(cx, ok_path, ResultOk);
+        then { path_to_local_id(ok_arg, param_id) } else { false }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/map_clone.rs b/src/tools/clippy/clippy_lints/src/methods/map_clone.rs
new file mode 100644
index 000000000000..8261ef5e1ce3
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/map_clone.rs
@@ -0,0 +1,122 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::{is_copy, is_type_diagnostic_item};
+use clippy_utils::{is_diag_trait_item, meets_msrv, msrvs, peel_blocks};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use rustc_middle::mir::Mutability;
+use rustc_middle::ty;
+use rustc_middle::ty::adjustment::Adjust;
+use rustc_semver::RustcVersion;
+use rustc_span::symbol::Ident;
+use rustc_span::{sym, Span};
+
+use super::MAP_CLONE;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'_>,
+    e: &hir::Expr<'_>,
+    recv: &hir::Expr<'_>,
+    arg: &'tcx hir::Expr<'_>,
+    msrv: Option<RustcVersion>,
+) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(e.hir_id);
+        if cx.tcx.impl_of_method(method_id)
+            .map_or(false, |id| is_type_diagnostic_item(cx, cx.tcx.type_of(id), sym::Option))
+            || is_diag_trait_item(cx, method_id, sym::Iterator);
+        if let hir::ExprKind::Closure(&hir::Closure{ body, .. }) = arg.kind;
+        then {
+            let closure_body = cx.tcx.hir().body(body);
+            let closure_expr = peel_blocks(closure_body.value);
+            match closure_body.params[0].pat.kind {
+                hir::PatKind::Ref(inner, hir::Mutability::Not) => if let hir::PatKind::Binding(
+                    hir::BindingAnnotation::NONE, .., name, None
+                ) = inner.kind {
+                    if ident_eq(name, closure_expr) {
+                        lint_explicit_closure(cx, e.span, recv.span, true, msrv);
+                    }
+                },
+                hir::PatKind::Binding(hir::BindingAnnotation::NONE, .., name, None) => {
+                    match closure_expr.kind {
+                        hir::ExprKind::Unary(hir::UnOp::Deref, inner) => {
+                            if ident_eq(name, inner) {
+                                if let ty::Ref(.., Mutability::Not) = cx.typeck_results().expr_ty(inner).kind() {
+                                    lint_explicit_closure(cx, e.span, recv.span, true, msrv);
+                                }
+                            }
+                        },
+                        hir::ExprKind::MethodCall(method, obj, [], _) => if_chain! {
+                            if ident_eq(name, obj) && method.ident.name == sym::clone;
+                            if let Some(fn_id) = cx.typeck_results().type_dependent_def_id(closure_expr.hir_id);
+                            if let Some(trait_id) = cx.tcx.trait_of_item(fn_id);
+                            if cx.tcx.lang_items().clone_trait().map_or(false, |id| id == trait_id);
+                            // no autoderefs
+                            if !cx.typeck_results().expr_adjustments(obj).iter()
+                                .any(|a| matches!(a.kind, Adjust::Deref(Some(..))));
+                            then {
+                                let obj_ty = cx.typeck_results().expr_ty(obj);
+                                if let ty::Ref(_, ty, mutability) = obj_ty.kind() {
+                                    if matches!(mutability, Mutability::Not) {
+                                        let copy = is_copy(cx, *ty);
+                                        lint_explicit_closure(cx, e.span, recv.span, copy, msrv);
+                                    }
+                                } else {
+                                    lint_needless_cloning(cx, e.span, recv.span);
+                                }
+                            }
+                        },
+                        _ => {},
+                    }
+                },
+                _ => {},
+            }
+        }
+    }
+}
+
+fn ident_eq(name: Ident, path: &hir::Expr<'_>) -> bool {
+    if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = path.kind {
+        path.segments.len() == 1 && path.segments[0].ident == name
+    } else {
+        false
+    }
+}
+
+fn lint_needless_cloning(cx: &LateContext<'_>, root: Span, receiver: Span) {
+    span_lint_and_sugg(
+        cx,
+        MAP_CLONE,
+        root.trim_start(receiver).unwrap(),
+        "you are needlessly cloning iterator elements",
+        "remove the `map` call",
+        String::new(),
+        Applicability::MachineApplicable,
+    );
+}
+
+fn lint_explicit_closure(cx: &LateContext<'_>, replace: Span, root: Span, is_copy: bool, msrv: Option<RustcVersion>) {
+    let mut applicability = Applicability::MachineApplicable;
+
+    let (message, sugg_method) = if is_copy && meets_msrv(msrv, msrvs::ITERATOR_COPIED) {
+        ("you are using an explicit closure for copying elements", "copied")
+    } else {
+        ("you are using an explicit closure for cloning elements", "cloned")
+    };
+
+    span_lint_and_sugg(
+        cx,
+        MAP_CLONE,
+        replace,
+        message,
+        &format!("consider calling the dedicated `{}` method", sugg_method),
+        format!(
+            "{}.{}()",
+            snippet_with_applicability(cx, root, "..", &mut applicability),
+            sugg_method,
+        ),
+        applicability,
+    );
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/map_err_ignore.rs b/src/tools/clippy/clippy_lints/src/methods/map_err_ignore.rs
new file mode 100644
index 000000000000..1fb6617145e7
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/map_err_ignore.rs
@@ -0,0 +1,34 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::is_type_diagnostic_item;
+use rustc_hir::{CaptureBy, Closure, Expr, ExprKind, PatKind};
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::MAP_ERR_IGNORE;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'_>, e: &Expr<'_>, arg: &'tcx Expr<'_>) {
+    if let Some(method_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
+        && let Some(impl_id) = cx.tcx.impl_of_method(method_id)
+        && is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Result)
+        && let ExprKind::Closure(&Closure {
+            capture_clause: CaptureBy::Ref,
+            body,
+            fn_decl_span,
+            ..
+        }) = arg.kind
+        && let closure_body = cx.tcx.hir().body(body)
+        && let [param] = closure_body.params
+        && let PatKind::Wild = param.pat.kind
+    {
+        // span the area of the closure capture and warn that the
+        // original error will be thrown away
+        span_lint_and_help(
+            cx,
+            MAP_ERR_IGNORE,
+            fn_decl_span,
+            "`map_err(|_|...` wildcard pattern discards the original error",
+            None,
+            "consider storing the original error as a source in the new error, or silence this warning using an ignored identifier (`.map_err(|_foo| ...`)",
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/mod.rs b/src/tools/clippy/clippy_lints/src/methods/mod.rs
index 5ac6b09f0aa2..ddb6d1ca26c9 100644
--- a/src/tools/clippy/clippy_lints/src/methods/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/mod.rs
@@ -1,5 +1,8 @@
 mod bind_instead_of_map;
+mod bytecount;
+mod bytes_count_to_len;
 mod bytes_nth;
+mod case_sensitive_file_extension_comparisons;
 mod chars_cmp;
 mod chars_cmp_with_unwrap;
 mod chars_last_cmp;
@@ -9,6 +12,7 @@ mod chars_next_cmp_with_unwrap;
 mod clone_on_copy;
 mod clone_on_ref_ptr;
 mod cloned_instead_of_copied;
+mod collapsible_str_replace;
 mod err_expect;
 mod expect_fun_call;
 mod expect_used;
@@ -21,6 +25,7 @@ mod filter_next;
 mod flat_map_identity;
 mod flat_map_option;
 mod from_iter_instead_of_collect;
+mod get_first;
 mod get_last_with_len;
 mod get_unwrap;
 mod implicit_clone;
@@ -30,58 +35,76 @@ mod into_iter_on_ref;
 mod is_digit_ascii_radix;
 mod iter_cloned_collect;
 mod iter_count;
+mod iter_kv_map;
 mod iter_next_slice;
 mod iter_nth;
 mod iter_nth_zero;
+mod iter_on_single_or_empty_collections;
 mod iter_overeager_cloned;
 mod iter_skip_next;
 mod iter_with_drain;
 mod iterator_step_by_zero;
+mod manual_ok_or;
 mod manual_saturating_arithmetic;
 mod manual_str_repeat;
+mod map_clone;
 mod map_collect_result_unit;
+mod map_err_ignore;
 mod map_flatten;
 mod map_identity;
 mod map_unwrap_or;
+mod mut_mutex_lock;
 mod needless_option_as_deref;
 mod needless_option_take;
 mod no_effect_replace;
 mod obfuscated_if_else;
 mod ok_expect;
+mod open_options;
 mod option_as_ref_deref;
 mod option_map_or_none;
 mod option_map_unwrap_or;
 mod or_fun_call;
 mod or_then_unwrap;
+mod path_buf_push_overwrite;
+mod range_zip_with_len;
+mod repeat_once;
 mod search_is_some;
 mod single_char_add_str;
 mod single_char_insert_string;
 mod single_char_pattern;
 mod single_char_push_string;
 mod skip_while_next;
+mod stable_sort_primitive;
 mod str_splitn;
 mod string_extend_chars;
 mod suspicious_map;
 mod suspicious_splitn;
+mod suspicious_to_owned;
 mod uninit_assumed_init;
+mod unit_hash;
 mod unnecessary_filter_map;
 mod unnecessary_fold;
 mod unnecessary_iter_cloned;
 mod unnecessary_join;
 mod unnecessary_lazy_eval;
+mod unnecessary_sort_by;
 mod unnecessary_to_owned;
 mod unwrap_or_else_default;
 mod unwrap_used;
 mod useless_asref;
 mod utils;
+mod vec_resize_to_zero;
+mod verbose_file_reads;
 mod wrong_self_convention;
 mod zst_offset;
 
 use bind_instead_of_map::BindInsteadOfMap;
 use clippy_utils::consts::{constant, Constant};
 use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
-use clippy_utils::ty::{contains_adt_constructor, contains_ty, implements_trait, is_copy, is_type_diagnostic_item};
-use clippy_utils::{contains_return, get_trait_def_id, iter_input_pats, meets_msrv, msrvs, paths, return_ty};
+use clippy_utils::ty::{contains_adt_constructor, implements_trait, is_copy, is_type_diagnostic_item};
+use clippy_utils::{
+    contains_return, get_trait_def_id, is_trait_method, iter_input_pats, meets_msrv, msrvs, paths, return_ty,
+};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
@@ -117,6 +140,32 @@ declare_clippy_lint! {
     "used `cloned` where `copied` could be used instead"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for consecutive calls to `str::replace` (2 or more)
+    /// that can be collapsed into a single call.
+    ///
+    /// ### Why is this bad?
+    /// Consecutive `str::replace` calls scan the string multiple times
+    /// with repetitive code.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let hello = "hesuo worpd"
+    ///     .replace('s', "l")
+    ///     .replace("u", "l")
+    ///     .replace('p', "l");
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// let hello = "hesuo worpd".replace(&['s', 'u', 'p'], "l");
+    /// ```
+    #[clippy::version = "1.64.0"]
+    pub COLLAPSIBLE_STR_REPLACE,
+    perf,
+    "collapse consecutive calls to str::replace (2 or more) into a single call"
+}
+
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for usage of `_.cloned().<func>()` where call to `.cloned()` can be postponed.
@@ -173,7 +222,7 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for `.unwrap()` calls on `Option`s and on `Result`s.
+    /// Checks for `.unwrap()` or `.unwrap_err()` calls on `Result`s and `.unwrap()` call on `Option`s.
     ///
     /// ### Why is this bad?
     /// It is better to handle the `None` or `Err` case,
@@ -223,7 +272,7 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for `.expect()` calls on `Option`s and `Result`s.
+    /// Checks for `.expect()` or `.expect_err()` calls on `Result`s and `.expect()` call on `Option`s.
     ///
     /// ### Why is this bad?
     /// Usually it is better to handle the `None` or `Err` case.
@@ -777,8 +826,9 @@ declare_clippy_lint! {
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for calls to `.or(foo(..))`, `.unwrap_or(foo(..))`,
-    /// etc., and suggests to use `or_else`, `unwrap_or_else`, etc., or
-    /// `unwrap_or_default` instead.
+    /// `.or_insert(foo(..))` etc., and suggests to use `.or_else(|| foo(..))`,
+    /// `.unwrap_or_else(|| foo(..))`, `.unwrap_or_default()` or `.or_default()`
+    /// etc. instead.
     ///
     /// ### Why is this bad?
     /// The function will always be called and potentially
@@ -2006,6 +2056,55 @@ declare_clippy_lint! {
     "replace `.iter().count()` with `.len()`"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for the usage of `_.to_owned()`, on a `Cow<'_, _>`.
+    ///
+    /// ### Why is this bad?
+    /// Calling `to_owned()` on a `Cow` creates a clone of the `Cow`
+    /// itself, without taking ownership of the `Cow` contents (i.e.
+    /// it's equivalent to calling `Cow::clone`).
+    /// The similarly named `into_owned` method, on the other hand,
+    /// clones the `Cow` contents, effectively turning any `Cow::Borrowed`
+    /// into a `Cow::Owned`.
+    ///
+    /// Given the potential ambiguity, consider replacing `to_owned`
+    /// with `clone` for better readability or, if getting a `Cow::Owned`
+    /// was the original intent, using `into_owned` instead.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # use std::borrow::Cow;
+    /// let s = "Hello world!";
+    /// let cow = Cow::Borrowed(s);
+    ///
+    /// let data = cow.to_owned();
+    /// assert!(matches!(data, Cow::Borrowed(_)))
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// # use std::borrow::Cow;
+    /// let s = "Hello world!";
+    /// let cow = Cow::Borrowed(s);
+    ///
+    /// let data = cow.clone();
+    /// assert!(matches!(data, Cow::Borrowed(_)))
+    /// ```
+    /// or
+    /// ```rust
+    /// # use std::borrow::Cow;
+    /// let s = "Hello world!";
+    /// let cow = Cow::Borrowed(s);
+    ///
+    /// let data = cow.into_owned();
+    /// assert!(matches!(data, String))
+    /// ```
+    #[clippy::version = "1.65.0"]
+    pub SUSPICIOUS_TO_OWNED,
+    suspicious,
+    "calls to `to_owned` on a `Cow<'_, _>` might not do what they are expected"
+}
+
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for calls to [`splitn`]
@@ -2269,7 +2368,7 @@ declare_clippy_lint! {
     /// "1234".replace("12", "12");
     /// "1234".replacen("12", "12", 1);
     /// ```
-    #[clippy::version = "1.62.0"]
+    #[clippy::version = "1.63.0"]
     pub NO_EFFECT_REPLACE,
     suspicious,
     "replace with no effect"
@@ -2304,6 +2403,671 @@ declare_clippy_lint! {
     more clearly with `if .. else ..`"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Checks for calls to `iter`, `iter_mut` or `into_iter` on collections containing a single item
+    ///
+    /// ### Why is this bad?
+    ///
+    /// It is simpler to use the once function from the standard library:
+    ///
+    /// ### Example
+    ///
+    /// ```rust
+    /// let a = [123].iter();
+    /// let b = Some(123).into_iter();
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// use std::iter;
+    /// let a = iter::once(&123);
+    /// let b = iter::once(123);
+    /// ```
+    ///
+    /// ### Known problems
+    ///
+    /// The type of the resulting iterator might become incompatible with its usage
+    #[clippy::version = "1.64.0"]
+    pub ITER_ON_SINGLE_ITEMS,
+    nursery,
+    "Iterator for array of length 1"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Checks for calls to `iter`, `iter_mut` or `into_iter` on empty collections
+    ///
+    /// ### Why is this bad?
+    ///
+    /// It is simpler to use the empty function from the standard library:
+    ///
+    /// ### Example
+    ///
+    /// ```rust
+    /// use std::{slice, option};
+    /// let a: slice::Iter<i32> = [].iter();
+    /// let f: option::IntoIter<i32> = None.into_iter();
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// use std::iter;
+    /// let a: iter::Empty<i32> = iter::empty();
+    /// let b: iter::Empty<i32> = iter::empty();
+    /// ```
+    ///
+    /// ### Known problems
+    ///
+    /// The type of the resulting iterator might become incompatible with its usage
+    #[clippy::version = "1.64.0"]
+    pub ITER_ON_EMPTY_COLLECTIONS,
+    nursery,
+    "Iterator for empty array"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for naive byte counts
+    ///
+    /// ### Why is this bad?
+    /// The [`bytecount`](https://crates.io/crates/bytecount)
+    /// crate has methods to count your bytes faster, especially for large slices.
+    ///
+    /// ### Known problems
+    /// If you have predominantly small slices, the
+    /// `bytecount::count(..)` method may actually be slower. However, if you can
+    /// ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
+    /// faster in those cases.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # let vec = vec![1_u8];
+    /// let count = vec.iter().filter(|x| **x == 0u8).count();
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// # let vec = vec![1_u8];
+    /// let count = bytecount::count(&vec, 0u8);
+    /// ```
+    #[clippy::version = "pre 1.29.0"]
+    pub NAIVE_BYTECOUNT,
+    pedantic,
+    "use of naive `<slice>.filter(|&x| x == y).count()` to count byte values"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// It checks for `str::bytes().count()` and suggests replacing it with
+    /// `str::len()`.
+    ///
+    /// ### Why is this bad?
+    /// `str::bytes().count()` is longer and may not be as performant as using
+    /// `str::len()`.
+    ///
+    /// ### Example
+    /// ```rust
+    /// "hello".bytes().count();
+    /// String::from("hello").bytes().count();
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// "hello".len();
+    /// String::from("hello").len();
+    /// ```
+    #[clippy::version = "1.62.0"]
+    pub BYTES_COUNT_TO_LEN,
+    complexity,
+    "Using `bytes().count()` when `len()` performs the same functionality"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for calls to `ends_with` with possible file extensions
+    /// and suggests to use a case-insensitive approach instead.
+    ///
+    /// ### Why is this bad?
+    /// `ends_with` is case-sensitive and may not detect files with a valid extension.
+    ///
+    /// ### Example
+    /// ```rust
+    /// fn is_rust_file(filename: &str) -> bool {
+    ///     filename.ends_with(".rs")
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// fn is_rust_file(filename: &str) -> bool {
+    ///     let filename = std::path::Path::new(filename);
+    ///     filename.extension()
+    ///         .map_or(false, |ext| ext.eq_ignore_ascii_case("rs"))
+    /// }
+    /// ```
+    #[clippy::version = "1.51.0"]
+    pub CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
+    pedantic,
+    "Checks for calls to ends_with with case-sensitive file extensions"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for using `x.get(0)` instead of
+    /// `x.first()`.
+    ///
+    /// ### Why is this bad?
+    /// Using `x.first()` is easier to read and has the same
+    /// result.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let x = vec![2, 3, 5];
+    /// let first_element = x.get(0);
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust
+    /// let x = vec![2, 3, 5];
+    /// let first_element = x.first();
+    /// ```
+    #[clippy::version = "1.63.0"]
+    pub GET_FIRST,
+    style,
+    "Using `x.get(0)` when `x.first()` is simpler"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Finds patterns that reimplement `Option::ok_or`.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Concise code helps focusing on behavior instead of boilerplate.
+    ///
+    /// ### Examples
+    /// ```rust
+    /// let foo: Option<i32> = None;
+    /// foo.map_or(Err("error"), |v| Ok(v));
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust
+    /// let foo: Option<i32> = None;
+    /// foo.ok_or("error");
+    /// ```
+    #[clippy::version = "1.49.0"]
+    pub MANUAL_OK_OR,
+    pedantic,
+    "finds patterns that can be encoded more concisely with `Option::ok_or`"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for usage of `map(|x| x.clone())` or
+    /// dereferencing closures for `Copy` types, on `Iterator` or `Option`,
+    /// and suggests `cloned()` or `copied()` instead
+    ///
+    /// ### Why is this bad?
+    /// Readability, this can be written more concisely
+    ///
+    /// ### Example
+    /// ```rust
+    /// let x = vec![42, 43];
+    /// let y = x.iter();
+    /// let z = y.map(|i| *i);
+    /// ```
+    ///
+    /// The correct use would be:
+    ///
+    /// ```rust
+    /// let x = vec![42, 43];
+    /// let y = x.iter();
+    /// let z = y.cloned();
+    /// ```
+    #[clippy::version = "pre 1.29.0"]
+    pub MAP_CLONE,
+    style,
+    "using `iterator.map(|x| x.clone())`, or dereferencing closures for `Copy` types"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for instances of `map_err(|_| Some::Enum)`
+    ///
+    /// ### Why is this bad?
+    /// This `map_err` throws away the original error rather than allowing the enum to contain and report the cause of the error
+    ///
+    /// ### Example
+    /// Before:
+    /// ```rust
+    /// use std::fmt;
+    ///
+    /// #[derive(Debug)]
+    /// enum Error {
+    ///     Indivisible,
+    ///     Remainder(u8),
+    /// }
+    ///
+    /// impl fmt::Display for Error {
+    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         match self {
+    ///             Error::Indivisible => write!(f, "could not divide input by three"),
+    ///             Error::Remainder(remainder) => write!(
+    ///                 f,
+    ///                 "input is not divisible by three, remainder = {}",
+    ///                 remainder
+    ///             ),
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// impl std::error::Error for Error {}
+    ///
+    /// fn divisible_by_3(input: &str) -> Result<(), Error> {
+    ///     input
+    ///         .parse::<i32>()
+    ///         .map_err(|_| Error::Indivisible)
+    ///         .map(|v| v % 3)
+    ///         .and_then(|remainder| {
+    ///             if remainder == 0 {
+    ///                 Ok(())
+    ///             } else {
+    ///                 Err(Error::Remainder(remainder as u8))
+    ///             }
+    ///         })
+    /// }
+    ///  ```
+    ///
+    ///  After:
+    ///  ```rust
+    /// use std::{fmt, num::ParseIntError};
+    ///
+    /// #[derive(Debug)]
+    /// enum Error {
+    ///     Indivisible(ParseIntError),
+    ///     Remainder(u8),
+    /// }
+    ///
+    /// impl fmt::Display for Error {
+    ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         match self {
+    ///             Error::Indivisible(_) => write!(f, "could not divide input by three"),
+    ///             Error::Remainder(remainder) => write!(
+    ///                 f,
+    ///                 "input is not divisible by three, remainder = {}",
+    ///                 remainder
+    ///             ),
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// impl std::error::Error for Error {
+    ///     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+    ///         match self {
+    ///             Error::Indivisible(source) => Some(source),
+    ///             _ => None,
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// fn divisible_by_3(input: &str) -> Result<(), Error> {
+    ///     input
+    ///         .parse::<i32>()
+    ///         .map_err(Error::Indivisible)
+    ///         .map(|v| v % 3)
+    ///         .and_then(|remainder| {
+    ///             if remainder == 0 {
+    ///                 Ok(())
+    ///             } else {
+    ///                 Err(Error::Remainder(remainder as u8))
+    ///             }
+    ///         })
+    /// }
+    /// ```
+    #[clippy::version = "1.48.0"]
+    pub MAP_ERR_IGNORE,
+    restriction,
+    "`map_err` should not ignore the original error"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for `&mut Mutex::lock` calls
+    ///
+    /// ### Why is this bad?
+    /// `Mutex::lock` is less efficient than
+    /// calling `Mutex::get_mut`. In addition you also have a statically
+    /// guarantee that the mutex isn't locked, instead of just a runtime
+    /// guarantee.
+    ///
+    /// ### Example
+    /// ```rust
+    /// use std::sync::{Arc, Mutex};
+    ///
+    /// let mut value_rc = Arc::new(Mutex::new(42_u8));
+    /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
+    ///
+    /// let mut value = value_mutex.lock().unwrap();
+    /// *value += 1;
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// use std::sync::{Arc, Mutex};
+    ///
+    /// let mut value_rc = Arc::new(Mutex::new(42_u8));
+    /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
+    ///
+    /// let value = value_mutex.get_mut().unwrap();
+    /// *value += 1;
+    /// ```
+    #[clippy::version = "1.49.0"]
+    pub MUT_MUTEX_LOCK,
+    style,
+    "`&mut Mutex::lock` does unnecessary locking"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for duplicate open options as well as combinations
+    /// that make no sense.
+    ///
+    /// ### Why is this bad?
+    /// In the best case, the code will be harder to read than
+    /// necessary. I don't know the worst case.
+    ///
+    /// ### Example
+    /// ```rust
+    /// use std::fs::OpenOptions;
+    ///
+    /// OpenOptions::new().read(true).truncate(true);
+    /// ```
+    #[clippy::version = "pre 1.29.0"]
+    pub NONSENSICAL_OPEN_OPTIONS,
+    correctness,
+    "nonsensical combination of options for opening a file"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///* Checks for [push](https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.push)
+    /// calls on `PathBuf` that can cause overwrites.
+    ///
+    /// ### Why is this bad?
+    /// Calling `push` with a root path at the start can overwrite the
+    /// previous defined path.
+    ///
+    /// ### Example
+    /// ```rust
+    /// use std::path::PathBuf;
+    ///
+    /// let mut x = PathBuf::from("/foo");
+    /// x.push("/bar");
+    /// assert_eq!(x, PathBuf::from("/bar"));
+    /// ```
+    /// Could be written:
+    ///
+    /// ```rust
+    /// use std::path::PathBuf;
+    ///
+    /// let mut x = PathBuf::from("/foo");
+    /// x.push("bar");
+    /// assert_eq!(x, PathBuf::from("/foo/bar"));
+    /// ```
+    #[clippy::version = "1.36.0"]
+    pub PATH_BUF_PUSH_OVERWRITE,
+    nursery,
+    "calling `push` with file system root on `PathBuf` can overwrite it"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for zipping a collection with the range of
+    /// `0.._.len()`.
+    ///
+    /// ### Why is this bad?
+    /// The code is better expressed with `.enumerate()`.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # let x = vec![1];
+    /// let _ = x.iter().zip(0..x.len());
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust
+    /// # let x = vec![1];
+    /// let _ = x.iter().enumerate();
+    /// ```
+    #[clippy::version = "pre 1.29.0"]
+    pub RANGE_ZIP_WITH_LEN,
+    complexity,
+    "zipping iterator with a range when `enumerate()` would do"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for usage of `.repeat(1)` and suggest the following method for each types.
+    /// - `.to_string()` for `str`
+    /// - `.clone()` for `String`
+    /// - `.to_vec()` for `slice`
+    ///
+    /// The lint will evaluate constant expressions and values as arguments of `.repeat(..)` and emit a message if
+    /// they are equivalent to `1`. (Related discussion in [rust-clippy#7306](https://github.com/rust-lang/rust-clippy/issues/7306))
+    ///
+    /// ### Why is this bad?
+    /// For example, `String.repeat(1)` is equivalent to `.clone()`. If cloning
+    /// the string is the intention behind this, `clone()` should be used.
+    ///
+    /// ### Example
+    /// ```rust
+    /// fn main() {
+    ///     let x = String::from("hello world").repeat(1);
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// fn main() {
+    ///     let x = String::from("hello world").clone();
+    /// }
+    /// ```
+    #[clippy::version = "1.47.0"]
+    pub REPEAT_ONCE,
+    complexity,
+    "using `.repeat(1)` instead of `String.clone()`, `str.to_string()` or `slice.to_vec()` "
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// When sorting primitive values (integers, bools, chars, as well
+    /// as arrays, slices, and tuples of such items), it is typically better to
+    /// use an unstable sort than a stable sort.
+    ///
+    /// ### Why is this bad?
+    /// Typically, using a stable sort consumes more memory and cpu cycles.
+    /// Because values which compare equal are identical, preserving their
+    /// relative order (the guarantee that a stable sort provides) means
+    /// nothing, while the extra costs still apply.
+    ///
+    /// ### Known problems
+    ///
+    /// As pointed out in
+    /// [issue #8241](https://github.com/rust-lang/rust-clippy/issues/8241),
+    /// a stable sort can instead be significantly faster for certain scenarios
+    /// (eg. when a sorted vector is extended with new data and resorted).
+    ///
+    /// For more information and benchmarking results, please refer to the
+    /// issue linked above.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let mut vec = vec![2, 1, 3];
+    /// vec.sort();
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// let mut vec = vec![2, 1, 3];
+    /// vec.sort_unstable();
+    /// ```
+    #[clippy::version = "1.47.0"]
+    pub STABLE_SORT_PRIMITIVE,
+    pedantic,
+    "use of sort() when sort_unstable() is equivalent"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Detects `().hash(_)`.
+    ///
+    /// ### Why is this bad?
+    /// Hashing a unit value doesn't do anything as the implementation of `Hash` for `()` is a no-op.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # use std::hash::Hash;
+    /// # use std::collections::hash_map::DefaultHasher;
+    /// # enum Foo { Empty, WithValue(u8) }
+    /// # use Foo::*;
+    /// # let mut state = DefaultHasher::new();
+    /// # let my_enum = Foo::Empty;
+    /// match my_enum {
+    /// 	Empty => ().hash(&mut state),
+    /// 	WithValue(x) => x.hash(&mut state),
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// # use std::hash::Hash;
+    /// # use std::collections::hash_map::DefaultHasher;
+    /// # enum Foo { Empty, WithValue(u8) }
+    /// # use Foo::*;
+    /// # let mut state = DefaultHasher::new();
+    /// # let my_enum = Foo::Empty;
+    /// match my_enum {
+    /// 	Empty => 0_u8.hash(&mut state),
+    /// 	WithValue(x) => x.hash(&mut state),
+    /// }
+    /// ```
+    #[clippy::version = "1.58.0"]
+    pub UNIT_HASH,
+    correctness,
+    "hashing a unit value, which does nothing"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Detects uses of `Vec::sort_by` passing in a closure
+    /// which compares the two arguments, either directly or indirectly.
+    ///
+    /// ### Why is this bad?
+    /// It is more clear to use `Vec::sort_by_key` (or `Vec::sort` if
+    /// possible) than to use `Vec::sort_by` and a more complicated
+    /// closure.
+    ///
+    /// ### Known problems
+    /// If the suggested `Vec::sort_by_key` uses Reverse and it isn't already
+    /// imported by a use statement, then it will need to be added manually.
+    ///
+    /// ### Example
+    /// ```rust
+    /// # struct A;
+    /// # impl A { fn foo(&self) {} }
+    /// # let mut vec: Vec<A> = Vec::new();
+    /// vec.sort_by(|a, b| a.foo().cmp(&b.foo()));
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// # struct A;
+    /// # impl A { fn foo(&self) {} }
+    /// # let mut vec: Vec<A> = Vec::new();
+    /// vec.sort_by_key(|a| a.foo());
+    /// ```
+    #[clippy::version = "1.46.0"]
+    pub UNNECESSARY_SORT_BY,
+    complexity,
+    "Use of `Vec::sort_by` when `Vec::sort_by_key` or `Vec::sort` would be clearer"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Finds occurrences of `Vec::resize(0, an_int)`
+    ///
+    /// ### Why is this bad?
+    /// This is probably an argument inversion mistake.
+    ///
+    /// ### Example
+    /// ```rust
+    /// vec!(1, 2, 3, 4, 5).resize(0, 5)
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust
+    /// vec!(1, 2, 3, 4, 5).clear()
+    /// ```
+    #[clippy::version = "1.46.0"]
+    pub VEC_RESIZE_TO_ZERO,
+    correctness,
+    "emptying a vector with `resize(0, an_int)` instead of `clear()` is probably an argument inversion mistake"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for use of File::read_to_end and File::read_to_string.
+    ///
+    /// ### Why is this bad?
+    /// `fs::{read, read_to_string}` provide the same functionality when `buf` is empty with fewer imports and no intermediate values.
+    /// See also: [fs::read docs](https://doc.rust-lang.org/std/fs/fn.read.html), [fs::read_to_string docs](https://doc.rust-lang.org/std/fs/fn.read_to_string.html)
+    ///
+    /// ### Example
+    /// ```rust,no_run
+    /// # use std::io::Read;
+    /// # use std::fs::File;
+    /// let mut f = File::open("foo.txt").unwrap();
+    /// let mut bytes = Vec::new();
+    /// f.read_to_end(&mut bytes).unwrap();
+    /// ```
+    /// Can be written more concisely as
+    /// ```rust,no_run
+    /// # use std::fs;
+    /// let mut bytes = fs::read("foo.txt").unwrap();
+    /// ```
+    #[clippy::version = "1.44.0"]
+    pub VERBOSE_FILE_READS,
+    restriction,
+    "use of `File::read_to_end` or `File::read_to_string`"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// Checks for iterating a map (`HashMap` or `BTreeMap`) and
+    /// ignoring either the keys or values.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Readability. There are `keys` and `values` methods that
+    /// can be used to express that we only need the keys or the values.
+    ///
+    /// ### Example
+    ///
+    /// ```
+    /// # use std::collections::HashMap;
+    /// let map: HashMap<u32, u32> = HashMap::new();
+    /// let values = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+    /// ```
+    ///
+    /// Use instead:
+    /// ```
+    /// # use std::collections::HashMap;
+    /// let map: HashMap<u32, u32> = HashMap::new();
+    /// let values = map.values().collect::<Vec<_>>();
+    /// ```
+    #[clippy::version = "1.65.0"]
+    pub ITER_KV_MAP,
+    complexity,
+    "iterating on map using `iter` when `keys` or `values` would do"
+}
+
 pub struct Methods {
     avoid_breaking_exported_api: bool,
     msrv: Option<RustcVersion>,
@@ -2347,6 +3111,7 @@ impl_lint_pass!(Methods => [
     CLONE_ON_COPY,
     CLONE_ON_REF_PTR,
     CLONE_DOUBLE_REF,
+    COLLAPSIBLE_STR_REPLACE,
     ITER_OVEREAGER_CLONED,
     CLONED_INSTEAD_OF_COPIED,
     FLAT_MAP_OPTION,
@@ -2393,6 +3158,7 @@ impl_lint_pass!(Methods => [
     FROM_ITER_INSTEAD_OF_COLLECT,
     INSPECT_FOR_EACH,
     IMPLICIT_CLONE,
+    SUSPICIOUS_TO_OWNED,
     SUSPICIOUS_SPLITN,
     MANUAL_STR_REPEAT,
     EXTEND_WITH_DRAIN,
@@ -2406,14 +3172,36 @@ impl_lint_pass!(Methods => [
     NEEDLESS_OPTION_TAKE,
     NO_EFFECT_REPLACE,
     OBFUSCATED_IF_ELSE,
+    ITER_ON_SINGLE_ITEMS,
+    ITER_ON_EMPTY_COLLECTIONS,
+    NAIVE_BYTECOUNT,
+    BYTES_COUNT_TO_LEN,
+    CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
+    GET_FIRST,
+    MANUAL_OK_OR,
+    MAP_CLONE,
+    MAP_ERR_IGNORE,
+    MUT_MUTEX_LOCK,
+    NONSENSICAL_OPEN_OPTIONS,
+    PATH_BUF_PUSH_OVERWRITE,
+    RANGE_ZIP_WITH_LEN,
+    REPEAT_ONCE,
+    STABLE_SORT_PRIMITIVE,
+    UNIT_HASH,
+    UNNECESSARY_SORT_BY,
+    VEC_RESIZE_TO_ZERO,
+    VERBOSE_FILE_READS,
+    ITER_KV_MAP,
 ]);
 
 /// Extracts a method call name, args, and `Span` of the method name.
-fn method_call<'tcx>(recv: &'tcx hir::Expr<'tcx>) -> Option<(&'tcx str, &'tcx [hir::Expr<'tcx>], Span)> {
-    if let ExprKind::MethodCall(path, args, _) = recv.kind {
-        if !args.iter().any(|e| e.span.from_expansion()) {
+fn method_call<'tcx>(
+    recv: &'tcx hir::Expr<'tcx>,
+) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span)> {
+    if let ExprKind::MethodCall(path, receiver, args, _) = recv.kind {
+        if !args.iter().any(|e| e.span.from_expansion()) && !receiver.span.from_expansion() {
             let name = path.ident.name.as_str();
-            return Some((name, args, path.ident.span));
+            return Some((name, receiver, args, path.ident.span));
         }
     }
     None
@@ -2431,17 +3219,17 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
             hir::ExprKind::Call(func, args) => {
                 from_iter_instead_of_collect::check(cx, expr, args, func);
             },
-            hir::ExprKind::MethodCall(method_call, args, _) => {
+            hir::ExprKind::MethodCall(method_call, receiver, args, _) => {
                 let method_span = method_call.ident.span;
-                or_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), args);
-                expect_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), args);
-                clone_on_copy::check(cx, expr, method_call.ident.name, args);
-                clone_on_ref_ptr::check(cx, expr, method_call.ident.name, args);
-                inefficient_to_string::check(cx, expr, method_call.ident.name, args);
-                single_char_add_str::check(cx, expr, args);
-                into_iter_on_ref::check(cx, expr, method_span, method_call.ident.name, args);
-                single_char_pattern::check(cx, expr, method_call.ident.name, args);
-                unnecessary_to_owned::check(cx, expr, method_call.ident.name, args, self.msrv);
+                or_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), receiver, args);
+                expect_fun_call::check(cx, expr, method_span, method_call.ident.as_str(), receiver, args);
+                clone_on_copy::check(cx, expr, method_call.ident.name, receiver, args);
+                clone_on_ref_ptr::check(cx, expr, method_call.ident.name, receiver, args);
+                inefficient_to_string::check(cx, expr, method_call.ident.name, receiver, args);
+                single_char_add_str::check(cx, expr, receiver, args);
+                into_iter_on_ref::check(cx, expr, method_span, method_call.ident.name, receiver);
+                single_char_pattern::check(cx, expr, method_call.ident.name, receiver, args);
+                unnecessary_to_owned::check(cx, expr, method_call.ident.name, receiver, args, self.msrv);
             },
             hir::ExprKind::Binary(op, lhs, rhs) if op.node == hir::BinOpKind::Eq || op.node == hir::BinOpKind::Ne => {
                 let mut info = BinaryExprInfo {
@@ -2462,7 +3250,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
             return;
         }
         let name = impl_item.ident.name.as_str();
-        let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+        let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
         let item = cx.tcx.hir().expect_item(parent);
         let self_ty = cx.tcx.type_of(item.def_id);
 
@@ -2471,7 +3259,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
             if let hir::ImplItemKind::Fn(ref sig, id) = impl_item.kind;
             if let Some(first_arg) = iter_input_pats(sig.decl, cx.tcx.hir().body(id)).next();
 
-            let method_sig = cx.tcx.fn_sig(impl_item.def_id);
+            let method_sig = cx.tcx.fn_sig(impl_item.def_id.def_id);
             let method_sig = cx.tcx.erase_late_bound_regions(method_sig);
 
             let first_arg_ty = method_sig.inputs().iter().next();
@@ -2481,7 +3269,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
 
             then {
                 // if this impl block implements a trait, lint in trait definition instead
-                if !implements_trait && cx.access_levels.is_exported(impl_item.def_id) {
+                if !implements_trait && cx.access_levels.is_exported(impl_item.def_id.def_id) {
                     // check missing trait implementations
                     for method_config in &TRAIT_METHODS {
                         if name == method_config.method_name &&
@@ -2513,7 +3301,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
 
                 if sig.decl.implicit_self.has_implicit_self()
                     && !(self.avoid_breaking_exported_api
-                        && cx.access_levels.is_exported(impl_item.def_id))
+                        && cx.access_levels.is_exported(impl_item.def_id.def_id))
                 {
                     wrong_self_convention::check(
                         cx,
@@ -2541,7 +3329,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
                 if contains_adt_constructor(ret_ty, self_adt) {
                     return;
                 }
-            } else if contains_ty(ret_ty, self_ty) {
+            } else if ret_ty.contains(self_ty) {
                 return;
             }
 
@@ -2550,16 +3338,16 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
                 // one of the associated types must be Self
                 for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) {
                     if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() {
-                        let assoc_ty = match projection_predicate.term {
-                            ty::Term::Ty(ty) => ty,
-                            ty::Term::Const(_c) => continue,
+                        let assoc_ty = match projection_predicate.term.unpack() {
+                            ty::TermKind::Ty(ty) => ty,
+                            ty::TermKind::Const(_c) => continue,
                         };
                         // walk the associated type and check for Self
                         if let Some(self_adt) = self_ty.ty_adt_def() {
                             if contains_adt_constructor(assoc_ty, self_adt) {
                                 return;
                             }
-                        } else if contains_ty(assoc_ty, self_ty) {
+                        } else if assoc_ty.contains(self_ty) {
                             return;
                         }
                     }
@@ -2608,7 +3396,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
             if let TraitItemKind::Fn(_, _) = item.kind;
             let ret_ty = return_ty(cx, item.hir_id());
             let self_ty = TraitRef::identity(cx.tcx, item.def_id.to_def_id()).self_ty().skip_binder();
-            if !contains_ty(ret_ty, self_ty);
+            if !ret_ty.contains(self_ty);
 
             then {
                 span_lint(
@@ -2627,7 +3415,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
 impl Methods {
     #[allow(clippy::too_many_lines)]
     fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if let Some((name, [recv, args @ ..], span)) = method_call(expr) {
+        if let Some((name, recv, args, span)) = method_call(expr) {
             match (name, args) {
                 ("add" | "offset" | "sub" | "wrapping_offset" | "wrapping_add" | "wrapping_sub", [_arg]) => {
                     zst_offset::check(cx, expr, recv);
@@ -2647,35 +3435,43 @@ impl Methods {
                 ("assume_init", []) => uninit_assumed_init::check(cx, expr, recv),
                 ("cloned", []) => cloned_instead_of_copied::check(cx, expr, recv, span, self.msrv),
                 ("collect", []) => match method_call(recv) {
-                    Some((name @ ("cloned" | "copied"), [recv2], _)) => {
+                    Some((name @ ("cloned" | "copied"), recv2, [], _)) => {
                         iter_cloned_collect::check(cx, name, expr, recv2);
                     },
-                    Some(("map", [m_recv, m_arg], _)) => {
+                    Some(("map", m_recv, [m_arg], _)) => {
                         map_collect_result_unit::check(cx, expr, m_recv, m_arg, recv);
                     },
-                    Some(("take", [take_self_arg, take_arg], _)) => {
+                    Some(("take", take_self_arg, [take_arg], _)) => {
                         if meets_msrv(self.msrv, msrvs::STR_REPEAT) {
                             manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg);
                         }
                     },
                     _ => {},
                 },
-                ("count", []) => match method_call(recv) {
-                    Some(("cloned", [recv2], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false),
-                    Some((name2 @ ("into_iter" | "iter" | "iter_mut"), [recv2], _)) => {
+                ("count", []) if is_trait_method(cx, expr, sym::Iterator) => match method_call(recv) {
+                    Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false),
+                    Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _)) => {
                         iter_count::check(cx, expr, recv2, name2);
                     },
-                    Some(("map", [_, arg], _)) => suspicious_map::check(cx, expr, recv, arg),
+                    Some(("map", _, [arg], _)) => suspicious_map::check(cx, expr, recv, arg),
+                    Some(("filter", recv2, [arg], _)) => bytecount::check(cx, expr, recv2, arg),
+                    Some(("bytes", recv2, [], _)) => bytes_count_to_len::check(cx, expr, recv, recv2),
                     _ => {},
                 },
                 ("drain", [arg]) => {
                     iter_with_drain::check(cx, expr, recv, span, arg);
                 },
-                ("expect", [_]) => match method_call(recv) {
-                    Some(("ok", [recv], _)) => ok_expect::check(cx, expr, recv),
-                    Some(("err", [recv], err_span)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span),
-                    _ => expect_used::check(cx, expr, recv, self.allow_expect_in_tests),
+                ("ends_with", [arg]) => {
+                    if let ExprKind::MethodCall(.., span) = expr.kind {
+                        case_sensitive_file_extension_comparisons::check(cx, expr, span, recv, arg);
+                    }
                 },
+                ("expect", [_]) => match method_call(recv) {
+                    Some(("ok", recv, [], _)) => ok_expect::check(cx, expr, recv),
+                    Some(("err", recv, [], err_span)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span),
+                    _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests),
+                },
+                ("expect_err", [_]) => expect_used::check(cx, expr, recv, true, self.allow_expect_in_tests),
                 ("extend", [arg]) => {
                     string_extend_chars::check(cx, expr, recv, arg);
                     extend_with_drain::check(cx, expr, recv, arg);
@@ -2692,36 +3488,56 @@ impl Methods {
                     flat_map_option::check(cx, expr, arg, span);
                 },
                 ("flatten", []) => match method_call(recv) {
-                    Some(("map", [recv, map_arg], map_span)) => map_flatten::check(cx, expr, recv, map_arg, map_span),
-                    Some(("cloned", [recv2], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true),
+                    Some(("map", recv, [map_arg], map_span)) => map_flatten::check(cx, expr, recv, map_arg, map_span),
+                    Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true),
                     _ => {},
                 },
                 ("fold", [init, acc]) => unnecessary_fold::check(cx, expr, init, acc, span),
                 ("for_each", [_]) => {
-                    if let Some(("inspect", [_, _], span2)) = method_call(recv) {
+                    if let Some(("inspect", _, [_], span2)) = method_call(recv) {
                         inspect_for_each::check(cx, expr, span2);
                     }
                 },
-                ("get", [arg]) => get_last_with_len::check(cx, expr, recv, arg),
+                ("get", [arg]) => {
+                    get_first::check(cx, expr, recv, arg);
+                    get_last_with_len::check(cx, expr, recv, arg);
+                },
                 ("get_or_insert_with", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "get_or_insert"),
+                ("hash", [arg]) => {
+                    unit_hash::check(cx, expr, recv, arg);
+                },
                 ("is_file", []) => filetype_is_file::check(cx, expr, recv),
                 ("is_digit", [radix]) => is_digit_ascii_radix::check(cx, expr, recv, radix, self.msrv),
                 ("is_none", []) => check_is_some_is_none(cx, expr, recv, false),
                 ("is_some", []) => check_is_some_is_none(cx, expr, recv, true),
+                ("iter" | "iter_mut" | "into_iter", []) => {
+                    iter_on_single_or_empty_collections::check(cx, expr, name, recv);
+                },
                 ("join", [join_arg]) => {
-                    if let Some(("collect", _, span)) = method_call(recv) {
+                    if let Some(("collect", _, _, span)) = method_call(recv) {
                         unnecessary_join::check(cx, expr, recv, join_arg, span);
                     }
                 },
                 ("last", []) | ("skip", [_]) => {
-                    if let Some((name2, [recv2, args2 @ ..], _span2)) = method_call(recv) {
+                    if let Some((name2, recv2, args2, _span2)) = method_call(recv) {
                         if let ("cloned", []) = (name2, args2) {
                             iter_overeager_cloned::check(cx, expr, recv, recv2, false, false);
                         }
                     }
                 },
+                ("lock", []) => {
+                    mut_mutex_lock::check(cx, expr, recv, span);
+                },
                 (name @ ("map" | "map_err"), [m_arg]) => {
-                    if let Some((name, [recv2, args @ ..], span2)) = method_call(recv) {
+                    if name == "map" {
+                        map_clone::check(cx, expr, recv, m_arg, self.msrv);
+                        if let Some((map_name @ ("iter" | "into_iter"), recv2, _, _)) = method_call(recv) {
+                            iter_kv_map::check(cx, map_name, expr, recv2, m_arg);
+                        }
+                    } else {
+                        map_err_ignore::check(cx, expr, m_arg);
+                    }
+                    if let Some((name, recv2, args, span2)) = method_call(recv) {
                         match (name, args) {
                             ("as_mut", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, true, self.msrv),
                             ("as_ref", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, false, self.msrv),
@@ -2736,9 +3552,12 @@ impl Methods {
                     }
                     map_identity::check(cx, expr, recv, m_arg, name, span);
                 },
-                ("map_or", [def, map]) => option_map_or_none::check(cx, expr, recv, def, map),
+                ("map_or", [def, map]) => {
+                    option_map_or_none::check(cx, expr, recv, def, map);
+                    manual_ok_or::check(cx, expr, recv, def, map);
+                },
                 ("next", []) => {
-                    if let Some((name2, [recv2, args2 @ ..], _)) = method_call(recv) {
+                    if let Some((name2, recv2, args2, _)) = method_call(recv) {
                         match (name2, args2) {
                             ("cloned", []) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
                             ("filter", [arg]) => filter_next::check(cx, expr, recv2, arg),
@@ -2751,18 +3570,53 @@ impl Methods {
                     }
                 },
                 ("nth", [n_arg]) => match method_call(recv) {
-                    Some(("bytes", [recv2], _)) => bytes_nth::check(cx, expr, recv2, n_arg),
-                    Some(("cloned", [recv2], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
-                    Some(("iter", [recv2], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
-                    Some(("iter_mut", [recv2], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
+                    Some(("bytes", recv2, [], _)) => bytes_nth::check(cx, expr, recv2, n_arg),
+                    Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),
+                    Some(("iter", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
+                    Some(("iter_mut", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
                     _ => iter_nth_zero::check(cx, expr, recv, n_arg),
                 },
                 ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"),
+                ("open", [_]) => {
+                    open_options::check(cx, expr, recv);
+                },
                 ("or_else", [arg]) => {
                     if !bind_instead_of_map::ResultOrElseErrInfo::check(cx, expr, recv, arg) {
                         unnecessary_lazy_eval::check(cx, expr, recv, arg, "or");
                     }
                 },
+                ("push", [arg]) => {
+                    path_buf_push_overwrite::check(cx, expr, arg);
+                },
+                ("read_to_end", [_]) => {
+                    verbose_file_reads::check(cx, expr, recv, verbose_file_reads::READ_TO_END_MSG);
+                },
+                ("read_to_string", [_]) => {
+                    verbose_file_reads::check(cx, expr, recv, verbose_file_reads::READ_TO_STRING_MSG);
+                },
+                ("repeat", [arg]) => {
+                    repeat_once::check(cx, expr, recv, arg);
+                },
+                (name @ ("replace" | "replacen"), [arg1, arg2] | [arg1, arg2, _]) => {
+                    no_effect_replace::check(cx, expr, arg1, arg2);
+
+                    // Check for repeated `str::replace` calls to perform `collapsible_str_replace` lint
+                    if name == "replace" && let Some(("replace", ..)) = method_call(recv) {
+                        collapsible_str_replace::check(cx, expr, arg1, arg2);
+                    }
+                },
+                ("resize", [count_arg, default_arg]) => {
+                    vec_resize_to_zero::check(cx, expr, count_arg, default_arg, span);
+                },
+                ("sort", []) => {
+                    stable_sort_primitive::check(cx, expr, recv);
+                },
+                ("sort_by", [arg]) => {
+                    unnecessary_sort_by::check(cx, expr, recv, arg, false);
+                },
+                ("sort_unstable_by", [arg]) => {
+                    unnecessary_sort_by::check(cx, expr, recv, arg, true);
+                },
                 ("splitn" | "rsplitn", [count_arg, pat_arg]) => {
                     if let Some((Constant::Int(count), _)) = constant(cx, cx.typeck_results(), count_arg) {
                         suspicious_splitn::check(cx, name, expr, recv, count);
@@ -2776,7 +3630,7 @@ impl Methods {
                 },
                 ("step_by", [arg]) => iterator_step_by_zero::check(cx, expr, arg),
                 ("take", [_arg]) => {
-                    if let Some((name2, [recv2, args2 @ ..], _span2)) = method_call(recv) {
+                    if let Some((name2, recv2, args2, _span2)) = method_call(recv) {
                         if let ("cloned", []) = (name2, args2) {
                             iter_overeager_cloned::check(cx, expr, recv, recv2, false, false);
                         }
@@ -2789,46 +3643,56 @@ impl Methods {
                     }
                     unnecessary_lazy_eval::check(cx, expr, recv, arg, "then_some");
                 },
-                ("to_os_string" | "to_owned" | "to_path_buf" | "to_vec", []) => {
+                ("to_owned", []) => {
+                    if !suspicious_to_owned::check(cx, expr, recv) {
+                        implicit_clone::check(cx, name, expr, recv);
+                    }
+                },
+                ("to_os_string" | "to_path_buf" | "to_vec", []) => {
                     implicit_clone::check(cx, name, expr, recv);
                 },
                 ("unwrap", []) => {
                     match method_call(recv) {
-                        Some(("get", [recv, get_arg], _)) => {
+                        Some(("get", recv, [get_arg], _)) => {
                             get_unwrap::check(cx, expr, recv, get_arg, false);
                         },
-                        Some(("get_mut", [recv, get_arg], _)) => {
+                        Some(("get_mut", recv, [get_arg], _)) => {
                             get_unwrap::check(cx, expr, recv, get_arg, true);
                         },
-                        Some(("or", [recv, or_arg], or_span)) => {
+                        Some(("or", recv, [or_arg], or_span)) => {
                             or_then_unwrap::check(cx, expr, recv, or_arg, or_span);
                         },
                         _ => {},
                     }
-                    unwrap_used::check(cx, expr, recv, self.allow_unwrap_in_tests);
+                    unwrap_used::check(cx, expr, recv, false, self.allow_unwrap_in_tests);
                 },
+                ("unwrap_err", []) => unwrap_used::check(cx, expr, recv, true, self.allow_unwrap_in_tests),
                 ("unwrap_or", [u_arg]) => match method_call(recv) {
-                    Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), [lhs, rhs], _)) => {
+                    Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _)) => {
                         manual_saturating_arithmetic::check(cx, expr, lhs, rhs, u_arg, &arith["checked_".len()..]);
                     },
-                    Some(("map", [m_recv, m_arg], span)) => {
+                    Some(("map", m_recv, [m_arg], span)) => {
                         option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span);
                     },
-                    Some(("then_some", [t_recv, t_arg], _)) => {
+                    Some(("then_some", t_recv, [t_arg], _)) => {
                         obfuscated_if_else::check(cx, expr, t_recv, t_arg, u_arg);
                     },
                     _ => {},
                 },
                 ("unwrap_or_else", [u_arg]) => match method_call(recv) {
-                    Some(("map", [recv, map_arg], _))
+                    Some(("map", recv, [map_arg], _))
                         if map_unwrap_or::check(cx, expr, recv, map_arg, u_arg, self.msrv) => {},
                     _ => {
                         unwrap_or_else_default::check(cx, expr, recv, u_arg);
                         unnecessary_lazy_eval::check(cx, expr, recv, u_arg, "unwrap_or");
                     },
                 },
-                ("replace" | "replacen", [arg1, arg2] | [arg1, arg2, _]) => {
-                    no_effect_replace::check(cx, expr, arg1, arg2);
+                ("zip", [arg]) => {
+                    if let ExprKind::MethodCall(name, iter_recv, [], _) = recv.kind
+                        && name.ident.name == sym::iter
+                    {
+                        range_zip_with_len::check(cx, expr, iter_recv, arg);
+                    }
                 },
                 _ => {},
             }
@@ -2837,7 +3701,7 @@ impl Methods {
 }
 
 fn check_is_some_is_none(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, is_some: bool) {
-    if let Some((name @ ("find" | "position" | "rposition"), [f_recv, arg], span)) = method_call(recv) {
+    if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span)) = method_call(recv) {
         search_is_some::check(cx, expr, name, is_some, f_recv, arg, recv, span);
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/mut_mutex_lock.rs b/src/tools/clippy/clippy_lints/src/methods/mut_mutex_lock.rs
new file mode 100644
index 000000000000..b9593b3687d9
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/mut_mutex_lock.rs
@@ -0,0 +1,31 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::{expr_custom_deref_adjustment, ty::is_type_diagnostic_item};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, Mutability};
+use rustc_lint::LateContext;
+use rustc_middle::ty;
+use rustc_span::{sym, Span};
+
+use super::MUT_MUTEX_LOCK;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, ex: &'tcx Expr<'tcx>, recv: &'tcx Expr<'tcx>, name_span: Span) {
+    if_chain! {
+        if matches!(expr_custom_deref_adjustment(cx, recv), None | Some(Mutability::Mut));
+        if let ty::Ref(_, _, Mutability::Mut) = cx.typeck_results().expr_ty(recv).kind();
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(ex.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Mutex);
+        then {
+            span_lint_and_sugg(
+                cx,
+                MUT_MUTEX_LOCK,
+                name_span,
+                "calling `&mut Mutex::lock` unnecessarily locks an exclusive (mutable) reference",
+                "change this to",
+                "get_mut".to_owned(),
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/ok_expect.rs b/src/tools/clippy/clippy_lints/src/methods/ok_expect.rs
index d64a9f320d90..646fc4a7bcf3 100644
--- a/src/tools/clippy/clippy_lints/src/methods/ok_expect.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/ok_expect.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
+use clippy_utils::ty::{has_debug_impl, is_type_diagnostic_item};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
@@ -15,7 +15,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
         if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), sym::Result);
         let result_type = cx.typeck_results().expr_ty(recv);
         if let Some(error_type) = get_error_type(cx, result_type);
-        if has_debug_impl(error_type, cx);
+        if has_debug_impl(cx, error_type);
 
         then {
             span_lint_and_help(
@@ -37,10 +37,3 @@ fn get_error_type<'a>(cx: &LateContext<'_>, ty: Ty<'a>) -> Option<Ty<'a>> {
         _ => None,
     }
 }
-
-/// This checks whether a given type is known to implement Debug.
-fn has_debug_impl<'tcx>(ty: Ty<'tcx>, cx: &LateContext<'tcx>) -> bool {
-    cx.tcx
-        .get_diagnostic_item(sym::Debug)
-        .map_or(false, |debug| implements_trait(cx, ty, debug, &[]))
-}
diff --git a/src/tools/clippy/clippy_lints/src/open_options.rs b/src/tools/clippy/clippy_lints/src/methods/open_options.rs
similarity index 75%
rename from src/tools/clippy/clippy_lints/src/open_options.rs
rename to src/tools/clippy/clippy_lints/src/methods/open_options.rs
index 5a0b5042018b..597af853dc68 100644
--- a/src/tools/clippy/clippy_lints/src/open_options.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/open_options.rs
@@ -3,43 +3,19 @@ use clippy_utils::paths;
 use clippy_utils::ty::match_type;
 use rustc_ast::ast::LitKind;
 use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_lint::LateContext;
 use rustc_span::source_map::{Span, Spanned};
 
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for duplicate open options as well as combinations
-    /// that make no sense.
-    ///
-    /// ### Why is this bad?
-    /// In the best case, the code will be harder to read than
-    /// necessary. I don't know the worst case.
-    ///
-    /// ### Example
-    /// ```rust
-    /// use std::fs::OpenOptions;
-    ///
-    /// OpenOptions::new().read(true).truncate(true);
-    /// ```
-    #[clippy::version = "pre 1.29.0"]
-    pub NONSENSICAL_OPEN_OPTIONS,
-    correctness,
-    "nonsensical combination of options for opening a file"
-}
+use super::NONSENSICAL_OPEN_OPTIONS;
 
-declare_lint_pass!(OpenOptions => [NONSENSICAL_OPEN_OPTIONS]);
-
-impl<'tcx> LateLintPass<'tcx> for OpenOptions {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
-        if let ExprKind::MethodCall(path, [self_arg, ..], _) = &e.kind {
-            let obj_ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
-            if path.ident.name == sym!(open) && match_type(cx, obj_ty, &paths::OPEN_OPTIONS) {
-                let mut options = Vec::new();
-                get_open_options(cx, self_arg, &mut options);
-                check_open_options(cx, &options, e.span);
-            }
-        }
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, recv: &'tcx Expr<'_>) {
+    if let Some(method_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
+        && let Some(impl_id) = cx.tcx.impl_of_method(method_id)
+        && match_type(cx, cx.tcx.type_of(impl_id), &paths::OPEN_OPTIONS)
+    {
+        let mut options = Vec::new();
+        get_open_options(cx, recv, &mut options);
+        check_open_options(cx, &options, e.span);
     }
 }
 
@@ -60,12 +36,12 @@ enum OpenOption {
 }
 
 fn get_open_options(cx: &LateContext<'_>, argument: &Expr<'_>, options: &mut Vec<(OpenOption, Argument)>) {
-    if let ExprKind::MethodCall(path, arguments, _) = argument.kind {
-        let obj_ty = cx.typeck_results().expr_ty(&arguments[0]).peel_refs();
+    if let ExprKind::MethodCall(path, receiver, arguments, _) = argument.kind {
+        let obj_ty = cx.typeck_results().expr_ty(receiver).peel_refs();
 
         // Only proceed if this is a call on some object of type std::fs::OpenOptions
-        if match_type(cx, obj_ty, &paths::OPEN_OPTIONS) && arguments.len() >= 2 {
-            let argument_option = match arguments[1].kind {
+        if match_type(cx, obj_ty, &paths::OPEN_OPTIONS) && !arguments.is_empty() {
+            let argument_option = match arguments[0].kind {
                 ExprKind::Lit(ref span) => {
                     if let Spanned {
                         node: LitKind::Bool(lit),
@@ -101,7 +77,7 @@ fn get_open_options(cx: &LateContext<'_>, argument: &Expr<'_>, options: &mut Vec
                 _ => (),
             }
 
-            get_open_options(cx, &arguments[0], options);
+            get_open_options(cx, receiver, options);
         }
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs b/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs
index 20cad0f181e9..c409268de769 100644
--- a/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs
@@ -53,16 +53,15 @@ pub(super) fn check<'tcx>(
             }),
         hir::ExprKind::Closure(&hir::Closure { body, .. }) => {
             let closure_body = cx.tcx.hir().body(body);
-            let closure_expr = peel_blocks(&closure_body.value);
+            let closure_expr = peel_blocks(closure_body.value);
 
             match &closure_expr.kind {
-                hir::ExprKind::MethodCall(_, args, _) => {
+                hir::ExprKind::MethodCall(_, receiver, [], _) => {
                     if_chain! {
-                        if args.len() == 1;
-                        if path_to_local_id(&args[0], closure_body.params[0].pat.hir_id);
+                        if path_to_local_id(receiver, closure_body.params[0].pat.hir_id);
                         let adj = cx
                             .typeck_results()
-                            .expr_adjustments(&args[0])
+                            .expr_adjustments(receiver)
                             .iter()
                             .map(|x| &x.kind)
                             .collect::<Box<[_]>>();
diff --git a/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs b/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs
index 5a39b82b027d..6657cdccd010 100644
--- a/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs
@@ -74,7 +74,7 @@ pub(super) fn check<'tcx>(
             if let hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }) = map_arg.kind;
             let arg_snippet = snippet(cx, fn_decl_span, "..");
             let body = cx.tcx.hir().body(body);
-            if let Some((func, [arg_char])) = reduce_unit_expression(&body.value);
+            if let Some((func, [arg_char])) = reduce_unit_expression(body.value);
             if let Some(id) = path_def_id(cx, func).map(|ctor_id| cx.tcx.parent(ctor_id));
             if Some(id) == cx.tcx.lang_items().option_some_variant();
             then {
diff --git a/src/tools/clippy/clippy_lints/src/methods/option_map_unwrap_or.rs b/src/tools/clippy/clippy_lints/src/methods/option_map_unwrap_or.rs
index 6c641af59f92..3c4002a3aef9 100644
--- a/src/tools/clippy/clippy_lints/src/methods/option_map_unwrap_or.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/option_map_unwrap_or.rs
@@ -78,7 +78,7 @@ pub(super) fn check<'tcx>(
                     map_span,
                     String::from(if unwrap_snippet_none { "and_then" } else { "map_or" }),
                 ),
-                (expr.span.with_lo(unwrap_recv.span.hi()), String::from("")),
+                (expr.span.with_lo(unwrap_recv.span.hi()), String::new()),
             ];
 
             if !unwrap_snippet_none {
diff --git a/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs b/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs
index 6af134019a47..b43b9258c471 100644
--- a/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/or_fun_call.rs
@@ -20,9 +20,11 @@ pub(super) fn check<'tcx>(
     expr: &hir::Expr<'_>,
     method_span: Span,
     name: &str,
+    receiver: &'tcx hir::Expr<'_>,
     args: &'tcx [hir::Expr<'_>],
 ) {
-    /// Checks for `unwrap_or(T::new())` or `unwrap_or(T::default())`.
+    /// Checks for `unwrap_or(T::new())`, `unwrap_or(T::default())`,
+    /// `or_insert(T::new())` or `or_insert(T::default())`.
     #[allow(clippy::too_many_arguments)]
     fn check_unwrap_or_default(
         cx: &LateContext<'_>,
@@ -42,7 +44,11 @@ pub(super) fn check<'tcx>(
 
         if_chain! {
             if !or_has_args;
-            if name == "unwrap_or";
+            if let Some(sugg) = match name {
+                "unwrap_or" => Some("unwrap_or_default"),
+                "or_insert" => Some("or_default"),
+                _ => None,
+            };
             if let hir::ExprKind::Path(ref qpath) = fun.kind;
             if let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default);
             let path = last_path_segment(qpath).ident.name;
@@ -58,7 +64,7 @@ pub(super) fn check<'tcx>(
                     method_span.with_hi(span.hi()),
                     &format!("use of `{}` followed by a call to `{}`", name, path),
                     "try this",
-                    "unwrap_or_default()".to_string(),
+                    format!("{}()", sugg),
                     Applicability::MachineApplicable,
                 );
 
@@ -82,7 +88,7 @@ pub(super) fn check<'tcx>(
         fun_span: Option<Span>,
     ) {
         // (path, fn_has_argument, methods, suffix)
-        static KNOW_TYPES: [(&[&str], bool, &[&str], &str); 4] = [
+        const KNOW_TYPES: [(&[&str], bool, &[&str], &str); 4] = [
             (&paths::BTREEMAP_ENTRY, false, &["or_insert"], "with"),
             (&paths::HASHMAP_ENTRY, false, &["or_insert"], "with"),
             (&paths::OPTION, false, &["map_or", "ok_or", "or", "unwrap_or"], "else"),
@@ -144,7 +150,7 @@ pub(super) fn check<'tcx>(
         }
     }
 
-    if let [self_arg, arg] = args {
+    if let [arg] = args {
         let inner_arg = if let hir::ExprKind::Block(
             hir::Block {
                 stmts: [],
@@ -163,11 +169,11 @@ pub(super) fn check<'tcx>(
                 let or_has_args = !or_args.is_empty();
                 if !check_unwrap_or_default(cx, name, fun, arg, or_has_args, expr.span, method_span) {
                     let fun_span = if or_has_args { None } else { Some(fun.span) };
-                    check_general_case(cx, name, method_span, self_arg, arg, expr.span, fun_span);
+                    check_general_case(cx, name, method_span, receiver, arg, expr.span, fun_span);
                 }
             },
             hir::ExprKind::Index(..) | hir::ExprKind::MethodCall(..) => {
-                check_general_case(cx, name, method_span, self_arg, arg, expr.span, None);
+                check_general_case(cx, name, method_span, receiver, arg, expr.span, None);
             },
             _ => (),
         }
diff --git a/src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs b/src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs
new file mode 100644
index 000000000000..0cc28c0dcb3d
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs
@@ -0,0 +1,37 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::symbol::sym;
+use std::path::{Component, Path};
+
+use super::PATH_BUF_PUSH_OVERWRITE;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arg: &'tcx Expr<'_>) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::PathBuf);
+        if let ExprKind::Lit(ref lit) = arg.kind;
+        if let LitKind::Str(ref path_lit, _) = lit.node;
+        if let pushed_path = Path::new(path_lit.as_str());
+        if let Some(pushed_path_lit) = pushed_path.to_str();
+        if pushed_path.has_root();
+        if let Some(root) = pushed_path.components().next();
+        if root == Component::RootDir;
+        then {
+            span_lint_and_sugg(
+                cx,
+                PATH_BUF_PUSH_OVERWRITE,
+                lit.span,
+                "calling `push` with '/' or '\\' (file system root) will overwrite the previous path definition",
+                "try",
+                format!("\"{}\"", pushed_path_lit.trim_start_matches(|c| c == '/' || c == '\\')),
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/range_zip_with_len.rs b/src/tools/clippy/clippy_lints/src/methods/range_zip_with_len.rs
new file mode 100644
index 000000000000..867a3b402377
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/range_zip_with_len.rs
@@ -0,0 +1,34 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::source::snippet;
+use clippy_utils::{higher, SpanlessEq};
+use clippy_utils::{is_integer_const, is_trait_method};
+use if_chain::if_chain;
+use rustc_hir::{Expr, ExprKind, QPath};
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::RANGE_ZIP_WITH_LEN;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, recv: &'tcx Expr<'_>, zip_arg: &'tcx Expr<'_>) {
+    if_chain! {
+        if is_trait_method(cx, expr, sym::Iterator);
+        // range expression in `.zip()` call: `0..x.len()`
+        if let Some(higher::Range { start: Some(start), end: Some(end), .. }) = higher::Range::hir(zip_arg);
+        if is_integer_const(cx, start, 0);
+        // `.len()` call
+        if let ExprKind::MethodCall(len_path, len_recv, [], _) = end.kind;
+        if len_path.ident.name == sym::len;
+        // `.iter()` and `.len()` called on same `Path`
+        if let ExprKind::Path(QPath::Resolved(_, iter_path)) = recv.kind;
+        if let ExprKind::Path(QPath::Resolved(_, len_path)) = len_recv.kind;
+        if SpanlessEq::new(cx).eq_path_segments(iter_path.segments, len_path.segments);
+        then {
+            span_lint(cx,
+                RANGE_ZIP_WITH_LEN,
+                expr.span,
+                &format!("it is more idiomatic to use `{}.iter().enumerate()`",
+                    snippet(cx, recv.span, "_"))
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/repeat_once.rs b/src/tools/clippy/clippy_lints/src/methods/repeat_once.rs
new file mode 100644
index 000000000000..0a14f9216ab3
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/repeat_once.rs
@@ -0,0 +1,52 @@
+use clippy_utils::consts::{constant_context, Constant};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::is_type_diagnostic_item;
+use rustc_errors::Applicability;
+use rustc_hir::Expr;
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::REPEAT_ONCE;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    recv: &'tcx Expr<'_>,
+    repeat_arg: &'tcx Expr<'_>,
+) {
+    if constant_context(cx, cx.typeck_results()).expr(repeat_arg) == Some(Constant::Int(1)) {
+        let ty = cx.typeck_results().expr_ty(recv).peel_refs();
+        if ty.is_str() {
+            span_lint_and_sugg(
+                cx,
+                REPEAT_ONCE,
+                expr.span,
+                "calling `repeat(1)` on str",
+                "consider using `.to_string()` instead",
+                format!("{}.to_string()", snippet(cx, recv.span, r#""...""#)),
+                Applicability::MachineApplicable,
+            );
+        } else if ty.builtin_index().is_some() {
+            span_lint_and_sugg(
+                cx,
+                REPEAT_ONCE,
+                expr.span,
+                "calling `repeat(1)` on slice",
+                "consider using `.to_vec()` instead",
+                format!("{}.to_vec()", snippet(cx, recv.span, r#""...""#)),
+                Applicability::MachineApplicable,
+            );
+        } else if is_type_diagnostic_item(cx, ty, sym::String) {
+            span_lint_and_sugg(
+                cx,
+                REPEAT_ONCE,
+                expr.span,
+                "calling `repeat(1)` on a string literal",
+                "consider using `.clone()` instead",
+                format!("{}.clone()", snippet(cx, recv.span, r#""...""#)),
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/single_char_add_str.rs b/src/tools/clippy/clippy_lints/src/methods/single_char_add_str.rs
index 9a5fabcf7cd5..81450fd8c6c3 100644
--- a/src/tools/clippy/clippy_lints/src/methods/single_char_add_str.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/single_char_add_str.rs
@@ -3,12 +3,12 @@ use clippy_utils::{match_def_path, paths};
 use rustc_hir as hir;
 use rustc_lint::LateContext;
 
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, receiver: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
     if let Some(fn_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) {
         if match_def_path(cx, fn_def_id, &paths::PUSH_STR) {
-            single_char_push_string::check(cx, expr, args);
+            single_char_push_string::check(cx, expr, receiver, args);
         } else if match_def_path(cx, fn_def_id, &paths::INSERT_STR) {
-            single_char_insert_string::check(cx, expr, args);
+            single_char_insert_string::check(cx, expr, receiver, args);
         }
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/single_char_insert_string.rs b/src/tools/clippy/clippy_lints/src/methods/single_char_insert_string.rs
index 6cdc954c03be..18b6b5be175d 100644
--- a/src/tools/clippy/clippy_lints/src/methods/single_char_insert_string.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/single_char_insert_string.rs
@@ -8,12 +8,12 @@ use rustc_lint::LateContext;
 use super::SINGLE_CHAR_ADD_STR;
 
 /// lint for length-1 `str`s as argument for `insert_str`
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, receiver: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
     let mut applicability = Applicability::MachineApplicable;
-    if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[2], &mut applicability) {
+    if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[1], &mut applicability) {
         let base_string_snippet =
-            snippet_with_applicability(cx, args[0].span.source_callsite(), "_", &mut applicability);
-        let pos_arg = snippet_with_applicability(cx, args[1].span, "..", &mut applicability);
+            snippet_with_applicability(cx, receiver.span.source_callsite(), "_", &mut applicability);
+        let pos_arg = snippet_with_applicability(cx, args[0].span, "..", &mut applicability);
         let sugg = format!("{}.insert({}, {})", base_string_snippet, pos_arg, extension_string);
         span_lint_and_sugg(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/methods/single_char_pattern.rs b/src/tools/clippy/clippy_lints/src/methods/single_char_pattern.rs
index bf9006c69062..4221c52d5cd7 100644
--- a/src/tools/clippy/clippy_lints/src/methods/single_char_pattern.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/single_char_pattern.rs
@@ -10,37 +10,43 @@ use rustc_span::symbol::Symbol;
 use super::SINGLE_CHAR_PATTERN;
 
 const PATTERN_METHODS: [(&str, usize); 24] = [
-    ("contains", 1),
-    ("starts_with", 1),
-    ("ends_with", 1),
-    ("find", 1),
-    ("rfind", 1),
-    ("split", 1),
-    ("split_inclusive", 1),
-    ("rsplit", 1),
-    ("split_terminator", 1),
-    ("rsplit_terminator", 1),
-    ("splitn", 2),
-    ("rsplitn", 2),
-    ("split_once", 1),
-    ("rsplit_once", 1),
-    ("matches", 1),
-    ("rmatches", 1),
-    ("match_indices", 1),
-    ("rmatch_indices", 1),
-    ("strip_prefix", 1),
-    ("strip_suffix", 1),
-    ("trim_start_matches", 1),
-    ("trim_end_matches", 1),
-    ("replace", 1),
-    ("replacen", 1),
+    ("contains", 0),
+    ("starts_with", 0),
+    ("ends_with", 0),
+    ("find", 0),
+    ("rfind", 0),
+    ("split", 0),
+    ("split_inclusive", 0),
+    ("rsplit", 0),
+    ("split_terminator", 0),
+    ("rsplit_terminator", 0),
+    ("splitn", 1),
+    ("rsplitn", 1),
+    ("split_once", 0),
+    ("rsplit_once", 0),
+    ("matches", 0),
+    ("rmatches", 0),
+    ("match_indices", 0),
+    ("rmatch_indices", 0),
+    ("strip_prefix", 0),
+    ("strip_suffix", 0),
+    ("trim_start_matches", 0),
+    ("trim_end_matches", 0),
+    ("replace", 0),
+    ("replacen", 0),
 ];
 
 /// lint for length-1 `str`s for methods in `PATTERN_METHODS`
-pub(super) fn check(cx: &LateContext<'_>, _expr: &hir::Expr<'_>, method_name: Symbol, args: &[hir::Expr<'_>]) {
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    _expr: &hir::Expr<'_>,
+    method_name: Symbol,
+    receiver: &hir::Expr<'_>,
+    args: &[hir::Expr<'_>],
+) {
     for &(method, pos) in &PATTERN_METHODS {
         if_chain! {
-            if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty_adjusted(&args[0]).kind();
+            if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty_adjusted(receiver).kind();
             if *ty.kind() == ty::Str;
             if method_name.as_str() == method && args.len() > pos;
             let arg = &args[pos];
diff --git a/src/tools/clippy/clippy_lints/src/methods/single_char_push_string.rs b/src/tools/clippy/clippy_lints/src/methods/single_char_push_string.rs
index 0237d39cbdb4..9ea6751956ab 100644
--- a/src/tools/clippy/clippy_lints/src/methods/single_char_push_string.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/single_char_push_string.rs
@@ -8,11 +8,11 @@ use rustc_lint::LateContext;
 use super::SINGLE_CHAR_ADD_STR;
 
 /// lint for length-1 `str`s as argument for `push_str`
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, receiver: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
     let mut applicability = Applicability::MachineApplicable;
-    if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[1], &mut applicability) {
+    if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[0], &mut applicability) {
         let base_string_snippet =
-            snippet_with_applicability(cx, args[0].span.source_callsite(), "..", &mut applicability);
+            snippet_with_applicability(cx, receiver.span.source_callsite(), "..", &mut applicability);
         let sugg = format!("{}.push({})", base_string_snippet, extension_string);
         span_lint_and_sugg(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/methods/stable_sort_primitive.rs b/src/tools/clippy/clippy_lints/src/methods/stable_sort_primitive.rs
new file mode 100644
index 000000000000..91951c65bb30
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/stable_sort_primitive.rs
@@ -0,0 +1,31 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::is_slice_of_primitives;
+use clippy_utils::source::snippet_with_context;
+use rustc_errors::Applicability;
+use rustc_hir::Expr;
+use rustc_lint::LateContext;
+
+use super::STABLE_SORT_PRIMITIVE;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, recv: &'tcx Expr<'_>) {
+    if let Some(method_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
+        && let Some(impl_id) = cx.tcx.impl_of_method(method_id)
+        && cx.tcx.type_of(impl_id).is_slice()
+        && let Some(slice_type) = is_slice_of_primitives(cx, recv)
+    {
+        span_lint_and_then(
+            cx,
+            STABLE_SORT_PRIMITIVE,
+            e.span,
+            &format!("used `sort` on primitive type `{}`", slice_type),
+            |diag| {
+                let mut app = Applicability::MachineApplicable;
+                let recv_snip = snippet_with_context(cx, recv.span, e.span.ctxt(), "..", &mut app).0;
+                diag.span_suggestion(e.span, "try", format!("{}.sort_unstable()", recv_snip), app);
+                diag.note(
+                    "an unstable sort typically performs faster without any observable difference for this data type",
+                );
+            },
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/str_splitn.rs b/src/tools/clippy/clippy_lints/src/methods/str_splitn.rs
index 4ac738272d08..9ca4d65550d3 100644
--- a/src/tools/clippy/clippy_lints/src/methods/str_splitn.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/str_splitn.rs
@@ -130,7 +130,7 @@ fn check_manual_split_once_indirect(
     let ctxt = expr.span.ctxt();
     let mut parents = cx.tcx.hir().parent_iter(expr.hir_id);
     if let (_, Node::Local(local)) = parents.next()?
-        && let PatKind::Binding(BindingAnnotation::Mutable, iter_binding_id, iter_ident, None) = local.pat.kind
+        && let PatKind::Binding(BindingAnnotation::MUT, iter_binding_id, iter_ident, None) = local.pat.kind
         && let (iter_stmt_id, Node::Stmt(_)) = parents.next()?
         && let (_, Node::Block(enclosing_block)) = parents.next()?
 
@@ -212,11 +212,10 @@ fn indirect_usage<'tcx>(
     ctxt: SyntaxContext,
 ) -> Option<IndirectUsage<'tcx>> {
     if let StmtKind::Local(Local {
-        pat:
-            Pat {
-                kind: PatKind::Binding(BindingAnnotation::Unannotated, _, ident, None),
-                ..
-            },
+        pat: Pat {
+            kind: PatKind::Binding(BindingAnnotation::NONE, _, ident, None),
+            ..
+        },
         init: Some(init_expr),
         hir_id: local_hir_id,
         ..
@@ -292,7 +291,7 @@ fn parse_iter_usage<'tcx>(
 ) -> Option<IterUsage> {
     let (kind, span) = match iter.next() {
         Some((_, Node::Expr(e))) if e.span.ctxt() == ctxt => {
-            let (name, args) = if let ExprKind::MethodCall(name, [_, args @ ..], _) = e.kind {
+            let (name, args) = if let ExprKind::MethodCall(name, _, [args @ ..], _) = e.kind {
                 (name, args)
             } else {
                 return None;
@@ -327,7 +326,7 @@ fn parse_iter_usage<'tcx>(
                         } else {
                             if_chain! {
                                 if let Some((_, Node::Expr(next_expr))) = iter.next();
-                                if let ExprKind::MethodCall(next_name, [_], _) = next_expr.kind;
+                                if let ExprKind::MethodCall(next_name, _, [], _) = next_expr.kind;
                                 if next_name.ident.name == sym::next;
                                 if next_expr.span.ctxt() == ctxt;
                                 if let Some(next_id) = cx.typeck_results().type_dependent_def_id(next_expr.hir_id);
@@ -367,7 +366,7 @@ fn parse_iter_usage<'tcx>(
                 }
             },
             _ if e.span.ctxt() != ctxt => (None, span),
-            ExprKind::MethodCall(name, [_], _)
+            ExprKind::MethodCall(name, _, [], _)
                 if name.ident.name == sym::unwrap
                     && cx
                         .typeck_results()
diff --git a/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs b/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs
index d06658f2a5e6..143dcee35052 100644
--- a/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs
@@ -16,7 +16,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
         return;
     }
     if let Some(arglists) = method_chain_args(arg, &["chars"]) {
-        let target = &arglists[0][0];
+        let target = &arglists[0].0;
         let self_ty = cx.typeck_results().expr_ty(target).peel_refs();
         let ref_str = if *self_ty.kind() == ty::Str {
             ""
diff --git a/src/tools/clippy/clippy_lints/src/methods/suspicious_map.rs b/src/tools/clippy/clippy_lints/src/methods/suspicious_map.rs
index 9c3375bf35e7..851cdf544550 100644
--- a/src/tools/clippy/clippy_lints/src/methods/suspicious_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/suspicious_map.rs
@@ -15,9 +15,9 @@ pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, count_recv: &hi
         if let Some(def_id) = cx.tcx.hir().opt_local_def_id(closure.hir_id);
         if let Some(body_id) = cx.tcx.hir().maybe_body_owned_by(def_id);
         let closure_body = cx.tcx.hir().body(body_id);
-        if !cx.typeck_results().expr_ty(&closure_body.value).is_unit();
+        if !cx.typeck_results().expr_ty(closure_body.value).is_unit();
         then {
-            if let Some(map_mutated_vars) = mutated_variables(&closure_body.value, cx) {
+            if let Some(map_mutated_vars) = mutated_variables(closure_body.value, cx) {
                 // A variable is used mutably inside of the closure. Suppress the lint.
                 if !map_mutated_vars.is_empty() {
                     return;
diff --git a/src/tools/clippy/clippy_lints/src/methods/suspicious_to_owned.rs b/src/tools/clippy/clippy_lints/src/methods/suspicious_to_owned.rs
new file mode 100644
index 000000000000..6b306fbf0085
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/suspicious_to_owned.rs
@@ -0,0 +1,36 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_diag_trait_item;
+use clippy_utils::source::snippet_with_context;
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use rustc_middle::ty;
+use rustc_span::sym;
+
+use super::SUSPICIOUS_TO_OWNED;
+
+pub fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>) -> bool {
+    if_chain! {
+        if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if is_diag_trait_item(cx, method_def_id, sym::ToOwned);
+        let input_type = cx.typeck_results().expr_ty(expr);
+        if let ty::Adt(adt, _) = cx.typeck_results().expr_ty(expr).kind();
+        if cx.tcx.is_diagnostic_item(sym::Cow, adt.did());
+        then {
+            let mut app = Applicability::MaybeIncorrect;
+            let recv_snip = snippet_with_context(cx, recv.span, expr.span.ctxt(), "..", &mut app).0;
+            span_lint_and_sugg(
+                cx,
+                SUSPICIOUS_TO_OWNED,
+                expr.span,
+                &format!("this `to_owned` call clones the {0} itself and does not cause the {0} contents to become owned", input_type),
+                "consider using, depending on intent",
+                format!("{0}.clone()` or `{0}.into_owned()", recv_snip),
+                app,
+            );
+            return true;
+        }
+    }
+    false
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/uninit_assumed_init.rs b/src/tools/clippy/clippy_lints/src/methods/uninit_assumed_init.rs
index 77d21f1d3730..a1c6294737cf 100644
--- a/src/tools/clippy/clippy_lints/src/methods/uninit_assumed_init.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/uninit_assumed_init.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint;
-use clippy_utils::{is_expr_diagnostic_item, ty::is_uninit_value_valid_for_ty};
+use clippy_utils::{is_path_diagnostic_item, ty::is_uninit_value_valid_for_ty};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
@@ -12,7 +12,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
     if_chain! {
         if let hir::ExprKind::Call(callee, args) = recv.kind;
         if args.is_empty();
-        if is_expr_diagnostic_item(cx, callee, sym::maybe_uninit_uninit);
+        if is_path_diagnostic_item(cx, callee, sym::maybe_uninit_uninit);
         if !is_uninit_value_valid_for_ty(cx, cx.typeck_results().expr_ty_adjusted(expr));
         then {
             span_lint(
diff --git a/src/tools/clippy/clippy_lints/src/methods/unit_hash.rs b/src/tools/clippy/clippy_lints/src/methods/unit_hash.rs
new file mode 100644
index 000000000000..3c7955bc4698
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/unit_hash.rs
@@ -0,0 +1,29 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::is_trait_method;
+use clippy_utils::source::snippet;
+use rustc_errors::Applicability;
+use rustc_hir::Expr;
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::UNIT_HASH;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, recv: &'tcx Expr<'_>, arg: &'tcx Expr<'_>) {
+    if is_trait_method(cx, expr, sym::Hash) && cx.typeck_results().expr_ty(recv).is_unit() {
+        span_lint_and_then(
+            cx,
+            UNIT_HASH,
+            expr.span,
+            "this call to `hash` on the unit type will do nothing",
+            |diag| {
+                diag.span_suggestion(
+                    expr.span,
+                    "remove the call to `hash` or consider using",
+                    format!("0_u8.hash({})", snippet(cx, arg.span, ".."),),
+                    Applicability::MaybeIncorrect,
+                );
+                diag.note("the implementation of `Hash` for `()` is a no-op");
+            },
+        );
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs
index bafa6fc584d4..4e8c201f470b 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs
@@ -21,14 +21,13 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<
     if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = arg.kind {
         let body = cx.tcx.hir().body(body);
         let arg_id = body.params[0].pat.hir_id;
-        let mutates_arg =
-            mutated_variables(&body.value, cx).map_or(true, |used_mutably| used_mutably.contains(&arg_id));
-        let (clone_or_copy_needed, _) = clone_or_copy_needed(cx, body.params[0].pat, &body.value);
+        let mutates_arg = mutated_variables(body.value, cx).map_or(true, |used_mutably| used_mutably.contains(&arg_id));
+        let (clone_or_copy_needed, _) = clone_or_copy_needed(cx, body.params[0].pat, body.value);
 
-        let (mut found_mapping, mut found_filtering) = check_expression(cx, arg_id, &body.value);
+        let (mut found_mapping, mut found_filtering) = check_expression(cx, arg_id, body.value);
 
         let mut return_visitor = ReturnVisitor::new(cx, arg_id);
-        return_visitor.visit_expr(&body.value);
+        return_visitor.visit_expr(body.value);
         found_mapping |= return_visitor.found_mapping;
         found_filtering |= return_visitor.found_filtering;
 
@@ -36,7 +35,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<
         let sugg = if !found_filtering {
             if name == "filter_map" { "map" } else { "map(..).next()" }
         } else if !found_mapping && !mutates_arg && (!clone_or_copy_needed || is_copy(cx, in_ty)) {
-            match cx.typeck_results().expr_ty(&body.value).kind() {
+            match cx.typeck_results().expr_ty(body.value).kind() {
                 ty::Adt(adt, subst)
                     if cx.tcx.is_diagnostic_item(sym::Option, adt.did()) && in_ty == subst.type_at(0) =>
                 {
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs
index c3531d4d0511..c17ef6809f91 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs
@@ -31,7 +31,7 @@ pub(super) fn check(
             // Extract the body of the closure passed to fold
             if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = acc.kind;
             let closure_body = cx.tcx.hir().body(body);
-            let closure_expr = peel_blocks(&closure_body.value);
+            let closure_expr = peel_blocks(closure_body.value);
 
             // Check if the closure body is of the form `acc <op> some_expr(x)`
             if let hir::ExprKind::Binary(ref bin_op, left_expr, right_expr) = closure_expr.kind;
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs
index 19037093e20a..95138c0e25b0 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs
@@ -43,7 +43,7 @@ pub fn check_for_loop_iter(
         if let Some(receiver_snippet) = snippet_opt(cx, receiver.span);
         then {
             let snippet = if_chain! {
-                if let ExprKind::MethodCall(maybe_iter_method_name, [collection], _) = receiver.kind;
+                if let ExprKind::MethodCall(maybe_iter_method_name, collection, [], _) = receiver.kind;
                 if maybe_iter_method_name.ident.name == sym::iter;
 
                 if let Some(iterator_trait_id) = cx.tcx.get_diagnostic_item(sym::Iterator);
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs
index 1876c7fb9d05..a187a8d6016f 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs
@@ -54,7 +54,7 @@ pub(super) fn check<'tcx>(
                 // This is a duplicate of what's happening in clippy_lints::methods::method_call,
                 // which isn't ideal, We want to get the method call span,
                 // but prefer to avoid changing the signature of the function itself.
-                if let hir::ExprKind::MethodCall(_, _, span) = expr.kind {
+                if let hir::ExprKind::MethodCall(.., span) = expr.kind {
                     span_lint_and_then(cx, UNNECESSARY_LAZY_EVALUATIONS, expr.span, msg, |diag| {
                         diag.span_suggestion(
                             span,
diff --git a/src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_sort_by.rs
similarity index 62%
rename from src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs
rename to src/tools/clippy/clippy_lints/src/methods/unnecessary_sort_by.rs
index ea5aadbbca1c..ed5a75b0f3ce 100644
--- a/src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_sort_by.rs
@@ -1,51 +1,17 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_trait_method;
 use clippy_utils::sugg::Sugg;
-use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
+use clippy_utils::ty::implements_trait;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Closure, Expr, ExprKind, Mutability, Param, Pat, PatKind, Path, PathSegment, QPath};
-use rustc_lint::{LateContext, LateLintPass};
+use rustc_lint::LateContext;
 use rustc_middle::ty::{self, subst::GenericArgKind};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 use rustc_span::symbol::Ident;
 use std::iter;
 
-declare_clippy_lint! {
-    /// ### What it does
-    /// Detects uses of `Vec::sort_by` passing in a closure
-    /// which compares the two arguments, either directly or indirectly.
-    ///
-    /// ### Why is this bad?
-    /// It is more clear to use `Vec::sort_by_key` (or `Vec::sort` if
-    /// possible) than to use `Vec::sort_by` and a more complicated
-    /// closure.
-    ///
-    /// ### Known problems
-    /// If the suggested `Vec::sort_by_key` uses Reverse and it isn't already
-    /// imported by a use statement, then it will need to be added manually.
-    ///
-    /// ### Example
-    /// ```rust
-    /// # struct A;
-    /// # impl A { fn foo(&self) {} }
-    /// # let mut vec: Vec<A> = Vec::new();
-    /// vec.sort_by(|a, b| a.foo().cmp(&b.foo()));
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// # struct A;
-    /// # impl A { fn foo(&self) {} }
-    /// # let mut vec: Vec<A> = Vec::new();
-    /// vec.sort_by_key(|a| a.foo());
-    /// ```
-    #[clippy::version = "1.46.0"]
-    pub UNNECESSARY_SORT_BY,
-    complexity,
-    "Use of `Vec::sort_by` when `Vec::sort_by_key` or `Vec::sort` would be clearer"
-}
-
-declare_lint_pass!(UnnecessarySortBy => [UNNECESSARY_SORT_BY]);
+use super::UNNECESSARY_SORT_BY;
 
 enum LintTrigger {
     Sort(SortDetection),
@@ -54,7 +20,6 @@ enum LintTrigger {
 
 struct SortDetection {
     vec_name: String,
-    unstable: bool,
 }
 
 struct SortByKeyDetection {
@@ -62,7 +27,6 @@ struct SortByKeyDetection {
     closure_arg: String,
     closure_body: String,
     reverse: bool,
-    unstable: bool,
 }
 
 /// Detect if the two expressions are mirrored (identical, except one
@@ -86,9 +50,13 @@ fn mirrored_exprs(a_expr: &Expr<'_>, a_ident: &Ident, b_expr: &Expr<'_>, b_ident
         // The two exprs are method calls.
         // Check to see that the function is the same and the arguments are mirrored
         // This is enough because the receiver of the method is listed in the arguments
-        (ExprKind::MethodCall(left_segment, left_args, _), ExprKind::MethodCall(right_segment, right_args, _)) => {
+        (
+            ExprKind::MethodCall(left_segment, left_receiver, left_args, _),
+            ExprKind::MethodCall(right_segment, right_receiver, right_args, _),
+        ) => {
             left_segment.ident == right_segment.ident
                 && iter::zip(*left_args, *right_args).all(|(left, right)| mirrored_exprs(left, a_ident, right, b_ident))
+                && mirrored_exprs(left_receiver, a_ident, right_receiver, b_ident)
         },
         // Two tuples with mirrored contents
         (ExprKind::Tup(left_exprs), ExprKind::Tup(right_exprs)) => {
@@ -150,20 +118,20 @@ fn mirrored_exprs(a_expr: &Expr<'_>, a_ident: &Ident, b_expr: &Expr<'_>, b_ident
     }
 }
 
-fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintTrigger> {
+fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, arg: &Expr<'_>) -> Option<LintTrigger> {
     if_chain! {
-        if let ExprKind::MethodCall(name_ident, args, _) = &expr.kind;
-        if let name = name_ident.ident.name.to_ident_string();
-        if name == "sort_by" || name == "sort_unstable_by";
-        if let [vec, Expr { kind: ExprKind::Closure(Closure { body: closure_body_id, .. }), .. }] = args;
-        if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(vec), sym::Vec);
-        if let closure_body = cx.tcx.hir().body(*closure_body_id);
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if cx.tcx.type_of(impl_id).is_slice();
+        if let ExprKind::Closure(&Closure { body, .. }) = arg.kind;
+        if let closure_body = cx.tcx.hir().body(body);
         if let &[
             Param { pat: Pat { kind: PatKind::Binding(_, _, left_ident, _), .. }, ..},
             Param { pat: Pat { kind: PatKind::Binding(_, _, right_ident, _), .. }, .. }
         ] = &closure_body.params;
-        if let ExprKind::MethodCall(method_path, [ref left_expr, ref right_expr], _) = &closure_body.value.kind;
+        if let ExprKind::MethodCall(method_path, left_expr, [right_expr], _) = closure_body.value.kind;
         if method_path.ident.name == sym::cmp;
+        if is_trait_method(cx, closure_body.value, sym::Ord);
         then {
             let (closure_body, closure_arg, reverse) = if mirrored_exprs(
                 left_expr,
@@ -177,19 +145,18 @@ fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintTrigger> {
             } else {
                 return None;
             };
-            let vec_name = Sugg::hir(cx, &args[0], "..").to_string();
-            let unstable = name == "sort_unstable_by";
+            let vec_name = Sugg::hir(cx, recv, "..").to_string();
 
             if_chain! {
-            if let ExprKind::Path(QPath::Resolved(_, Path {
-                segments: [PathSegment { ident: left_name, .. }], ..
-            })) = &left_expr.kind;
-            if left_name == left_ident;
-            if cx.tcx.get_diagnostic_item(sym::Ord).map_or(false, |id| {
-                implements_trait(cx, cx.typeck_results().expr_ty(left_expr), id, &[])
-            });
+                if let ExprKind::Path(QPath::Resolved(_, Path {
+                    segments: [PathSegment { ident: left_name, .. }], ..
+                })) = &left_expr.kind;
+                if left_name == left_ident;
+                if cx.tcx.get_diagnostic_item(sym::Ord).map_or(false, |id| {
+                    implements_trait(cx, cx.typeck_results().expr_ty(left_expr), id, &[])
+                });
                 then {
-                    return Some(LintTrigger::Sort(SortDetection { vec_name, unstable }));
+                    return Some(LintTrigger::Sort(SortDetection { vec_name }));
                 }
             }
 
@@ -199,7 +166,6 @@ fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintTrigger> {
                     closure_arg,
                     closure_body,
                     reverse,
-                    unstable,
                 }));
             }
         }
@@ -213,46 +179,50 @@ fn expr_borrows(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     matches!(ty.kind(), ty::Ref(..)) || ty.walk().any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_)))
 }
 
-impl LateLintPass<'_> for UnnecessarySortBy {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        match detect_lint(cx, expr) {
-            Some(LintTrigger::SortByKey(trigger)) => span_lint_and_sugg(
-                cx,
-                UNNECESSARY_SORT_BY,
-                expr.span,
-                "use Vec::sort_by_key here instead",
-                "try",
-                format!(
-                    "{}.sort{}_by_key(|{}| {})",
-                    trigger.vec_name,
-                    if trigger.unstable { "_unstable" } else { "" },
-                    trigger.closure_arg,
-                    if trigger.reverse {
-                        format!("std::cmp::Reverse({})", trigger.closure_body)
-                    } else {
-                        trigger.closure_body.to_string()
-                    },
-                ),
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    recv: &'tcx Expr<'_>,
+    arg: &'tcx Expr<'_>,
+    is_unstable: bool,
+) {
+    match detect_lint(cx, expr, recv, arg) {
+        Some(LintTrigger::SortByKey(trigger)) => span_lint_and_sugg(
+            cx,
+            UNNECESSARY_SORT_BY,
+            expr.span,
+            "use Vec::sort_by_key here instead",
+            "try",
+            format!(
+                "{}.sort{}_by_key(|{}| {})",
+                trigger.vec_name,
+                if is_unstable { "_unstable" } else { "" },
+                trigger.closure_arg,
                 if trigger.reverse {
-                    Applicability::MaybeIncorrect
+                    format!("std::cmp::Reverse({})", trigger.closure_body)
                 } else {
-                    Applicability::MachineApplicable
+                    trigger.closure_body.to_string()
                 },
             ),
-            Some(LintTrigger::Sort(trigger)) => span_lint_and_sugg(
-                cx,
-                UNNECESSARY_SORT_BY,
-                expr.span,
-                "use Vec::sort here instead",
-                "try",
-                format!(
-                    "{}.sort{}()",
-                    trigger.vec_name,
-                    if trigger.unstable { "_unstable" } else { "" },
-                ),
-                Applicability::MachineApplicable,
+            if trigger.reverse {
+                Applicability::MaybeIncorrect
+            } else {
+                Applicability::MachineApplicable
+            },
+        ),
+        Some(LintTrigger::Sort(trigger)) => span_lint_and_sugg(
+            cx,
+            UNNECESSARY_SORT_BY,
+            expr.span,
+            "use Vec::sort here instead",
+            "try",
+            format!(
+                "{}.sort{}()",
+                trigger.vec_name,
+                if is_unstable { "_unstable" } else { "" },
             ),
-            None => {},
-        }
+            Applicability::MachineApplicable,
+        ),
+        None => {},
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
index b3276f1394ed..79d784c342ca 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
@@ -2,21 +2,23 @@ use super::implicit_clone::is_clone_like;
 use super::unnecessary_iter_cloned::{self, is_into_iter};
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_opt;
-use clippy_utils::ty::{
-    contains_ty, get_associated_type, get_iterator_item_ty, implements_trait, is_copy, peel_mid_ty_refs,
-};
+use clippy_utils::ty::{get_associated_type, get_iterator_item_ty, implements_trait, is_copy, peel_mid_ty_refs};
+use clippy_utils::visitors::find_all_ret_expressions;
+use clippy_utils::{fn_def_id, get_parent_expr, is_diag_item_method, is_diag_trait_item, return_ty};
 use clippy_utils::{meets_msrv, msrvs};
-
-use clippy_utils::{fn_def_id, get_parent_expr, is_diag_item_method, is_diag_trait_item};
 use rustc_errors::Applicability;
-use rustc_hir::{def_id::DefId, BorrowKind, Expr, ExprKind};
+use rustc_hir::{def_id::DefId, BorrowKind, Expr, ExprKind, ItemKind, LangItem, Node};
+use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::LateContext;
 use rustc_middle::mir::Mutability;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, OverloadedDeref};
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
-use rustc_middle::ty::{self, PredicateKind, ProjectionPredicate, TraitPredicate, Ty};
+use rustc_middle::ty::EarlyBinder;
+use rustc_middle::ty::{self, ParamTy, PredicateKind, ProjectionPredicate, TraitPredicate, Ty};
 use rustc_semver::RustcVersion;
 use rustc_span::{sym, Symbol};
+use rustc_trait_selection::traits::{query::evaluate_obligation::InferCtxtExt as _, Obligation, ObligationCause};
+use rustc_typeck::check::{FnCtxt, Inherited};
 use std::cmp::max;
 
 use super::UNNECESSARY_TO_OWNED;
@@ -25,16 +27,17 @@ pub fn check<'tcx>(
     cx: &LateContext<'tcx>,
     expr: &'tcx Expr<'tcx>,
     method_name: Symbol,
-    args: &'tcx [Expr<'tcx>],
+    receiver: &'tcx Expr<'_>,
+    args: &'tcx [Expr<'_>],
     msrv: Option<RustcVersion>,
 ) {
     if_chain! {
         if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
-        if let [receiver] = args;
+        if args.is_empty();
         then {
             if is_cloned_or_copied(cx, method_name, method_def_id) {
                 unnecessary_iter_cloned::check(cx, expr, method_name, receiver);
-            } else if is_to_owned_like(cx, method_name, method_def_id) {
+            } else if is_to_owned_like(cx, expr, method_name, method_def_id) {
                 // At this point, we know the call is of a `to_owned`-like function. The functions
                 // `check_addr_of_expr` and `check_call_arg` determine whether the call is unnecessary
                 // based on its context, that is, whether it is a referent in an `AddrOf` expression, an
@@ -246,12 +249,12 @@ fn check_other_call_arg<'tcx>(
 ) -> bool {
     if_chain! {
         if let Some((maybe_call, maybe_arg)) = skip_addr_of_ancestors(cx, expr);
-        if let Some((callee_def_id, call_substs, call_args)) = get_callee_substs_and_args(cx, maybe_call);
+        if let Some((callee_def_id, _, recv, call_args)) = get_callee_substs_and_args(cx, maybe_call);
         let fn_sig = cx.tcx.fn_sig(callee_def_id).skip_binder();
-        if let Some(i) = call_args.iter().position(|arg| arg.hir_id == maybe_arg.hir_id);
+        if let Some(i) = recv.into_iter().chain(call_args).position(|arg| arg.hir_id == maybe_arg.hir_id);
         if let Some(input) = fn_sig.inputs().get(i);
         let (input, n_refs) = peel_mid_ty_refs(*input);
-        if let (trait_predicates, projection_predicates) = get_input_traits_and_projections(cx, callee_def_id, input);
+        if let (trait_predicates, _) = get_input_traits_and_projections(cx, callee_def_id, input);
         if let Some(sized_def_id) = cx.tcx.lang_items().sized_trait();
         if let [trait_predicate] = trait_predicates
             .iter()
@@ -259,40 +262,13 @@ fn check_other_call_arg<'tcx>(
             .collect::<Vec<_>>()[..];
         if let Some(deref_trait_id) = cx.tcx.get_diagnostic_item(sym::Deref);
         if let Some(as_ref_trait_id) = cx.tcx.get_diagnostic_item(sym::AsRef);
+        if trait_predicate.def_id() == deref_trait_id || trait_predicate.def_id() == as_ref_trait_id;
         let receiver_ty = cx.typeck_results().expr_ty(receiver);
-        // If the callee has type parameters, they could appear in `projection_predicate.ty` or the
-        // types of `trait_predicate.trait_ref.substs`.
-        if if trait_predicate.def_id() == deref_trait_id {
-            if let [projection_predicate] = projection_predicates[..] {
-                let normalized_ty =
-                    cx.tcx
-                        .subst_and_normalize_erasing_regions(call_substs, cx.param_env, projection_predicate.term);
-                implements_trait(cx, receiver_ty, deref_trait_id, &[])
-                    && get_associated_type(cx, receiver_ty, deref_trait_id, "Target")
-                        .map_or(false, |ty| ty::Term::Ty(ty) == normalized_ty)
-            } else {
-                false
-            }
-        } else if trait_predicate.def_id() == as_ref_trait_id {
-            let composed_substs = compose_substs(
-                cx,
-                &trait_predicate.trait_ref.substs.iter().skip(1).collect::<Vec<_>>()[..],
-                call_substs,
-            );
-            implements_trait(cx, receiver_ty, as_ref_trait_id, &composed_substs)
-        } else {
-            false
-        };
+        if can_change_type(cx, maybe_arg, receiver_ty);
         // We can't add an `&` when the trait is `Deref` because `Target = &T` won't match
         // `Target = T`.
         if n_refs > 0 || is_copy(cx, receiver_ty) || trait_predicate.def_id() != deref_trait_id;
-        let n_refs = max(n_refs, if is_copy(cx, receiver_ty) { 0 } else { 1 });
-        // If the trait is `AsRef` and the input type variable `T` occurs in the output type, then
-        // `T` must not be instantiated with a reference
-        // (https://github.com/rust-lang/rust-clippy/issues/8507).
-        if (n_refs == 0 && !receiver_ty.is_ref())
-            || trait_predicate.def_id() != as_ref_trait_id
-            || !contains_ty(fn_sig.output(), input);
+        let n_refs = max(n_refs, usize::from(!is_copy(cx, receiver_ty)));
         if let Some(receiver_snippet) = snippet_opt(cx, receiver.span);
         then {
             span_lint_and_sugg(
@@ -331,22 +307,22 @@ fn skip_addr_of_ancestors<'tcx>(
 fn get_callee_substs_and_args<'tcx>(
     cx: &LateContext<'tcx>,
     expr: &'tcx Expr<'tcx>,
-) -> Option<(DefId, SubstsRef<'tcx>, &'tcx [Expr<'tcx>])> {
+) -> Option<(DefId, SubstsRef<'tcx>, Option<&'tcx Expr<'tcx>>, &'tcx [Expr<'tcx>])> {
     if_chain! {
         if let ExprKind::Call(callee, args) = expr.kind;
         let callee_ty = cx.typeck_results().expr_ty(callee);
         if let ty::FnDef(callee_def_id, _) = callee_ty.kind();
         then {
             let substs = cx.typeck_results().node_substs(callee.hir_id);
-            return Some((*callee_def_id, substs, args));
+            return Some((*callee_def_id, substs, None, args));
         }
     }
     if_chain! {
-        if let ExprKind::MethodCall(_, args, _) = expr.kind;
+        if let ExprKind::MethodCall(_, recv, args, _) = expr.kind;
         if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
         then {
             let substs = cx.typeck_results().node_substs(expr.hir_id);
-            return Some((method_def_id, substs, args));
+            return Some((method_def_id, substs, Some(recv), args));
         }
     }
     None
@@ -360,25 +336,15 @@ fn get_input_traits_and_projections<'tcx>(
 ) -> (Vec<TraitPredicate<'tcx>>, Vec<ProjectionPredicate<'tcx>>) {
     let mut trait_predicates = Vec::new();
     let mut projection_predicates = Vec::new();
-    for (predicate, _) in cx.tcx.predicates_of(callee_def_id).predicates.iter() {
-        // `substs` should have 1 + n elements. The first is the type on the left hand side of an
-        // `as`. The remaining n are trait parameters.
-        let is_input_substs = |substs: SubstsRef<'tcx>| {
-            if_chain! {
-                if let Some(arg) = substs.iter().next();
-                if let GenericArgKind::Type(arg_ty) = arg.unpack();
-                if arg_ty == input;
-                then { true } else { false }
-            }
-        };
+    for predicate in cx.tcx.param_env(callee_def_id).caller_bounds() {
         match predicate.kind().skip_binder() {
             PredicateKind::Trait(trait_predicate) => {
-                if is_input_substs(trait_predicate.trait_ref.substs) {
+                if trait_predicate.trait_ref.self_ty() == input {
                     trait_predicates.push(trait_predicate);
                 }
             },
             PredicateKind::Projection(projection_predicate) => {
-                if is_input_substs(projection_predicate.projection_ty.substs) {
+                if projection_predicate.projection_ty.self_ty() == input {
                     projection_predicates.push(projection_predicate);
                 }
             },
@@ -388,22 +354,107 @@ fn get_input_traits_and_projections<'tcx>(
     (trait_predicates, projection_predicates)
 }
 
-/// Composes two substitutions by applying the latter to the types of the former.
-fn compose_substs<'tcx>(
-    cx: &LateContext<'tcx>,
-    left: &[GenericArg<'tcx>],
-    right: SubstsRef<'tcx>,
-) -> Vec<GenericArg<'tcx>> {
-    left.iter()
-        .map(|arg| {
-            if let GenericArgKind::Type(arg_ty) = arg.unpack() {
-                let normalized_ty = cx.tcx.subst_and_normalize_erasing_regions(right, cx.param_env, arg_ty);
-                GenericArg::from(normalized_ty)
-            } else {
-                *arg
+fn can_change_type<'a>(cx: &LateContext<'a>, mut expr: &'a Expr<'a>, mut ty: Ty<'a>) -> bool {
+    for (_, node) in cx.tcx.hir().parent_iter(expr.hir_id) {
+        match node {
+            Node::Stmt(_) => return true,
+            Node::Block(..) => continue,
+            Node::Item(item) => {
+                if let ItemKind::Fn(_, _, body_id) = &item.kind
+                && let output_ty = return_ty(cx, item.hir_id())
+                && let local_def_id = cx.tcx.hir().local_def_id(item.hir_id())
+                && Inherited::build(cx.tcx, local_def_id).enter(|inherited| {
+                    let fn_ctxt = FnCtxt::new(&inherited, cx.param_env, item.hir_id());
+                    fn_ctxt.can_coerce(ty, output_ty)
+                }) {
+                    if has_lifetime(output_ty) && has_lifetime(ty) {
+                        return false;
+                    }
+                    let body = cx.tcx.hir().body(*body_id);
+                    let body_expr = &body.value;
+                    let mut count = 0;
+                    return find_all_ret_expressions(cx, body_expr, |_| { count += 1; count <= 1 });
+                }
             }
-        })
-        .collect()
+            Node::Expr(parent_expr) => {
+                if let Some((callee_def_id, call_substs, recv, call_args)) = get_callee_substs_and_args(cx, parent_expr)
+                {
+                    if cx.tcx.lang_items().require(LangItem::IntoFutureIntoFuture) == Ok(callee_def_id) {
+                        return false;
+                    }
+
+                    let fn_sig = cx.tcx.fn_sig(callee_def_id).skip_binder();
+                    if let Some(arg_index) = recv.into_iter().chain(call_args).position(|arg| arg.hir_id == expr.hir_id)
+                        && let Some(param_ty) = fn_sig.inputs().get(arg_index)
+                        && let ty::Param(ParamTy { index: param_index , ..}) = param_ty.kind()
+                    {
+                        if fn_sig
+                            .inputs()
+                            .iter()
+                            .enumerate()
+                            .filter(|(i, _)| *i != arg_index)
+                            .any(|(_, ty)| ty.contains(*param_ty))
+                        {
+                            return false;
+                        }
+
+                        let mut trait_predicates = cx.tcx.param_env(callee_def_id)
+                            .caller_bounds().iter().filter(|predicate| {
+                            if let PredicateKind::Trait(trait_predicate) =  predicate.kind().skip_binder()
+                                && trait_predicate.trait_ref.self_ty() == *param_ty {
+                                    true
+                                } else {
+                                false
+                            }
+                        });
+
+                        let new_subst = cx.tcx.mk_substs(
+                            call_substs.iter()
+                                .enumerate()
+                                .map(|(i, t)|
+                                     if i == (*param_index as usize) {
+                                         GenericArg::from(ty)
+                                     } else {
+                                         t
+                                     }));
+
+                        if trait_predicates.any(|predicate| {
+                            let predicate = EarlyBinder(predicate).subst(cx.tcx, new_subst);
+                            let obligation = Obligation::new(ObligationCause::dummy(), cx.param_env, predicate);
+                            !cx.tcx
+                                .infer_ctxt()
+                                .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
+                        }) {
+                            return false;
+                        }
+
+                        let output_ty = fn_sig.output();
+                        if output_ty.contains(*param_ty) {
+                            if let Ok(new_ty)  = cx.tcx.try_subst_and_normalize_erasing_regions(
+                                new_subst, cx.param_env, output_ty) {
+                                expr = parent_expr;
+                                ty = new_ty;
+                                continue;
+                            }
+                            return false;
+                        }
+
+                        return true;
+                    }
+                } else if let ExprKind::Block(..) = parent_expr.kind {
+                    continue;
+                }
+                return false;
+            },
+            _ => return false,
+        }
+    }
+
+    false
+}
+
+fn has_lifetime(ty: Ty<'_>) -> bool {
+    ty.walk().any(|t| matches!(t.unpack(), GenericArgKind::Lifetime(_)))
 }
 
 /// Returns true if the named method is `Iterator::cloned` or `Iterator::copied`.
@@ -414,10 +465,10 @@ fn is_cloned_or_copied(cx: &LateContext<'_>, method_name: Symbol, method_def_id:
 
 /// Returns true if the named method can be used to convert the receiver to its "owned"
 /// representation.
-fn is_to_owned_like(cx: &LateContext<'_>, method_name: Symbol, method_def_id: DefId) -> bool {
+fn is_to_owned_like<'a>(cx: &LateContext<'a>, call_expr: &Expr<'a>, method_name: Symbol, method_def_id: DefId) -> bool {
     is_clone_like(cx, method_name.as_str(), method_def_id)
         || is_cow_into_owned(cx, method_name, method_def_id)
-        || is_to_string(cx, method_name, method_def_id)
+        || is_to_string_on_string_like(cx, call_expr, method_name, method_def_id)
 }
 
 /// Returns true if the named method is `Cow::into_owned`.
@@ -425,7 +476,27 @@ fn is_cow_into_owned(cx: &LateContext<'_>, method_name: Symbol, method_def_id: D
     method_name.as_str() == "into_owned" && is_diag_item_method(cx, method_def_id, sym::Cow)
 }
 
-/// Returns true if the named method is `ToString::to_string`.
-fn is_to_string(cx: &LateContext<'_>, method_name: Symbol, method_def_id: DefId) -> bool {
-    method_name == sym::to_string && is_diag_trait_item(cx, method_def_id, sym::ToString)
+/// Returns true if the named method is `ToString::to_string` and it's called on a type that
+/// is string-like i.e. implements `AsRef<str>` or `Deref<str>`.
+fn is_to_string_on_string_like<'a>(
+    cx: &LateContext<'_>,
+    call_expr: &'a Expr<'a>,
+    method_name: Symbol,
+    method_def_id: DefId,
+) -> bool {
+    if method_name != sym::to_string || !is_diag_trait_item(cx, method_def_id, sym::ToString) {
+        return false;
+    }
+
+    if let Some(substs) = cx.typeck_results().node_substs_opt(call_expr.hir_id)
+        && let [generic_arg] = substs.as_slice()
+        && let GenericArgKind::Type(ty) = generic_arg.unpack()
+        && let Some(deref_trait_id) = cx.tcx.get_diagnostic_item(sym::Deref)
+        && let Some(as_ref_trait_id) = cx.tcx.get_diagnostic_item(sym::AsRef)
+        && (implements_trait(cx, ty, deref_trait_id, &[cx.tcx.types.str_.into()]) ||
+            implements_trait(cx, ty, as_ref_trait_id, &[cx.tcx.types.str_.into()])) {
+            true
+        } else {
+            false
+        }
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/unwrap_or_else_default.rs b/src/tools/clippy/clippy_lints/src/methods/unwrap_or_else_default.rs
index f3af281d6cac..045f739e64de 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unwrap_or_else_default.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unwrap_or_else_default.rs
@@ -5,10 +5,11 @@ use clippy_utils::{
     diagnostics::span_lint_and_sugg, is_default_equivalent_call, source::snippet_with_applicability,
     ty::is_type_diagnostic_item,
 };
+use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
-use rustc_span::sym;
+use rustc_span::{sym, symbol};
 
 pub(super) fn check<'tcx>(
     cx: &LateContext<'tcx>,
@@ -25,7 +26,7 @@ pub(super) fn check<'tcx>(
 
     if_chain! {
         if is_option || is_result;
-        if is_default_equivalent_call(cx, u_arg);
+        if closure_body_returns_empty_to_string(cx, u_arg) || is_default_equivalent_call(cx, u_arg);
         then {
             let mut applicability = Applicability::MachineApplicable;
 
@@ -44,3 +45,22 @@ pub(super) fn check<'tcx>(
         }
     }
 }
+
+fn closure_body_returns_empty_to_string(cx: &LateContext<'_>, e: &hir::Expr<'_>) -> bool {
+    if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = e.kind {
+        let body = cx.tcx.hir().body(body);
+
+        if body.params.is_empty()
+            && let hir::Expr{ kind, .. } = &body.value
+            && let hir::ExprKind::MethodCall(hir::PathSegment {ident, ..}, self_arg, _, _) = kind
+            && ident == &symbol::Ident::from_str("to_string")
+            && let hir::Expr{ kind, .. } = self_arg
+            && let hir::ExprKind::Lit(lit) = kind
+            && let LitKind::Str(symbol::kw::Empty, _) = lit.node
+        {
+            return true;
+        }
+    }
+
+    false
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/unwrap_used.rs b/src/tools/clippy/clippy_lints/src/methods/unwrap_used.rs
index ce1a52e5480a..ee17f2d7889e 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unwrap_used.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unwrap_used.rs
@@ -7,18 +7,26 @@ use rustc_span::sym;
 
 use super::{EXPECT_USED, UNWRAP_USED};
 
-/// lint use of `unwrap()` for `Option`s and `Result`s
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, allow_unwrap_in_tests: bool) {
+/// lint use of `unwrap()` or `unwrap_err` for `Result` and `unwrap()` for `Option`.
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &hir::Expr<'_>,
+    recv: &hir::Expr<'_>,
+    is_err: bool,
+    allow_unwrap_in_tests: bool,
+) {
     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
 
-    let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) {
+    let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) && !is_err {
         Some((UNWRAP_USED, "an Option", "None", ""))
     } else if is_type_diagnostic_item(cx, obj_ty, sym::Result) {
-        Some((UNWRAP_USED, "a Result", "Err", "an "))
+        Some((UNWRAP_USED, "a Result", if is_err { "Ok" } else { "Err" }, "an "))
     } else {
         None
     };
 
+    let method_suffix = if is_err { "_err" } else { "" };
+
     if allow_unwrap_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
         return;
     }
@@ -27,7 +35,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
         let help = if is_lint_allowed(cx, EXPECT_USED, expr.hir_id) {
             format!(
                 "if you don't want to handle the `{none_value}` case gracefully, consider \
-                using `expect()` to provide a better panic message"
+                using `expect{method_suffix}()` to provide a better panic message"
             )
         } else {
             format!("if this value is {none_prefix}`{none_value}`, it will panic")
@@ -37,7 +45,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
             cx,
             lint,
             expr.span,
-            &format!("used `unwrap()` on `{kind}` value"),
+            &format!("used `unwrap{method_suffix}()` on `{kind}` value"),
             None,
             &help,
         );
diff --git a/src/tools/clippy/clippy_lints/src/methods/utils.rs b/src/tools/clippy/clippy_lints/src/methods/utils.rs
index 3015531e8439..ae6b165fdc36 100644
--- a/src/tools/clippy/clippy_lints/src/methods/utils.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/utils.rs
@@ -28,7 +28,7 @@ pub(super) fn derefs_to_slice<'tcx>(
         }
     }
 
-    if let hir::ExprKind::MethodCall(path, [self_arg, ..], _) = &expr.kind {
+    if let hir::ExprKind::MethodCall(path, self_arg, ..) = &expr.kind {
         if path.ident.name == sym::iter && may_slice(cx, cx.typeck_results().expr_ty(self_arg)) {
             Some(self_arg)
         } else {
@@ -139,9 +139,9 @@ impl<'cx, 'tcx> Visitor<'tcx> for CloneOrCopyVisitor<'cx, 'tcx> {
                         self.addr_of_exprs.push(parent);
                         return;
                     },
-                    ExprKind::MethodCall(_, args, _) => {
+                    ExprKind::MethodCall(.., args, _) => {
                         if_chain! {
-                            if args.iter().skip(1).all(|arg| !self.is_binding(arg));
+                            if args.iter().all(|arg| !self.is_binding(arg));
                             if let Some(method_def_id) = self.cx.typeck_results().type_dependent_def_id(parent.hir_id);
                             let method_ty = self.cx.tcx.type_of(method_def_id);
                             let self_ty = method_ty.fn_sig(self.cx.tcx).input(0).skip_binder();
diff --git a/src/tools/clippy/clippy_lints/src/methods/vec_resize_to_zero.rs b/src/tools/clippy/clippy_lints/src/methods/vec_resize_to_zero.rs
new file mode 100644
index 000000000000..02d8364cb295
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/vec_resize_to_zero.rs
@@ -0,0 +1,45 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::source_map::Spanned;
+use rustc_span::{sym, Span};
+
+use super::VEC_RESIZE_TO_ZERO;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    count_arg: &'tcx Expr<'_>,
+    default_arg: &'tcx Expr<'_>,
+    name_span: Span,
+) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Vec);
+        if let ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = count_arg.kind;
+        if let ExprKind::Lit(Spanned { node: LitKind::Int(..), .. }) = default_arg.kind;
+        then {
+            let method_call_span = expr.span.with_lo(name_span.lo());
+            span_lint_and_then(
+                cx,
+                VEC_RESIZE_TO_ZERO,
+                expr.span,
+                "emptying a vector with `resize`",
+                |db| {
+                    db.help("the arguments may be inverted...");
+                    db.span_suggestion(
+                        method_call_span,
+                        "...or you can empty the vector with",
+                        "clear()".to_string(),
+                        Applicability::MaybeIncorrect,
+                    );
+                },
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/verbose_file_reads.rs b/src/tools/clippy/clippy_lints/src/methods/verbose_file_reads.rs
new file mode 100644
index 000000000000..2fe5ae9a9ad8
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/verbose_file_reads.rs
@@ -0,0 +1,28 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::is_trait_method;
+use clippy_utils::ty::is_type_diagnostic_item;
+use rustc_hir::{Expr, ExprKind, QPath};
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::VERBOSE_FILE_READS;
+
+pub(super) const READ_TO_END_MSG: (&str, &str) = ("use of `File::read_to_end`", "consider using `fs::read` instead");
+pub(super) const READ_TO_STRING_MSG: (&str, &str) = (
+    "use of `File::read_to_string`",
+    "consider using `fs::read_to_string` instead",
+);
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    recv: &'tcx Expr<'_>,
+    (msg, help): (&str, &str),
+) {
+    if is_trait_method(cx, expr, sym::IoRead)
+        && matches!(recv.kind, ExprKind::Path(QPath::Resolved(None, _)))
+        && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty_adjusted(recv).peel_refs(), sym::File)
+    {
+        span_lint_and_help(cx, VERBOSE_FILE_READS, expr.span, msg, None, help);
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/minmax.rs b/src/tools/clippy/clippy_lints/src/minmax.rs
index a081cde85725..4d8579135fc0 100644
--- a/src/tools/clippy/clippy_lints/src/minmax.rs
+++ b/src/tools/clippy/clippy_lints/src/minmax.rs
@@ -1,7 +1,6 @@
 use clippy_utils::consts::{constant_simple, Constant};
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::{match_trait_method, paths};
-use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -75,45 +74,49 @@ fn min_max<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<(MinMax, Cons
                     .qpath_res(qpath, path.hir_id)
                     .opt_def_id()
                     .and_then(|def_id| match cx.tcx.get_diagnostic_name(def_id) {
-                        Some(sym::cmp_min) => fetch_const(cx, args, MinMax::Min),
-                        Some(sym::cmp_max) => fetch_const(cx, args, MinMax::Max),
+                        Some(sym::cmp_min) => fetch_const(cx, None, args, MinMax::Min),
+                        Some(sym::cmp_max) => fetch_const(cx, None, args, MinMax::Max),
                         _ => None,
                     })
             } else {
                 None
             }
         },
-        ExprKind::MethodCall(path, args, _) => {
-            if_chain! {
-                if let [obj, _] = args;
-                if cx.typeck_results().expr_ty(obj).is_floating_point() || match_trait_method(cx, expr, &paths::ORD);
-                then {
-                    if path.ident.name == sym!(max) {
-                        fetch_const(cx, args, MinMax::Max)
-                    } else if path.ident.name == sym!(min) {
-                        fetch_const(cx, args, MinMax::Min)
-                    } else {
-                        None
-                    }
+        ExprKind::MethodCall(path, receiver, args @ [_], _) => {
+            if cx.typeck_results().expr_ty(receiver).is_floating_point() || match_trait_method(cx, expr, &paths::ORD) {
+                if path.ident.name == sym!(max) {
+                    fetch_const(cx, Some(receiver), args, MinMax::Max)
+                } else if path.ident.name == sym!(min) {
+                    fetch_const(cx, Some(receiver), args, MinMax::Min)
                 } else {
                     None
                 }
+            } else {
+                None
             }
         },
         _ => None,
     }
 }
 
-fn fetch_const<'a>(cx: &LateContext<'_>, args: &'a [Expr<'a>], m: MinMax) -> Option<(MinMax, Constant, &'a Expr<'a>)> {
-    if args.len() != 2 {
+fn fetch_const<'a>(
+    cx: &LateContext<'_>,
+    receiver: Option<&'a Expr<'a>>,
+    args: &'a [Expr<'a>],
+    m: MinMax,
+) -> Option<(MinMax, Constant, &'a Expr<'a>)> {
+    let mut args = receiver.into_iter().chain(args);
+    let first_arg = args.next()?;
+    let second_arg = args.next()?;
+    if args.next().is_some() {
         return None;
     }
-    constant_simple(cx, cx.typeck_results(), &args[0]).map_or_else(
-        || constant_simple(cx, cx.typeck_results(), &args[1]).map(|c| (m, c, &args[0])),
+    constant_simple(cx, cx.typeck_results(), first_arg).map_or_else(
+        || constant_simple(cx, cx.typeck_results(), second_arg).map(|c| (m, c, first_arg)),
         |c| {
-            if constant_simple(cx, cx.typeck_results(), &args[1]).is_none() {
+            if constant_simple(cx, cx.typeck_results(), second_arg).is_none() {
                 // otherwise ignore
-                Some((m, c, &args[1]))
+                Some((m, c, second_arg))
             } else {
                 None
             }
diff --git a/src/tools/clippy/clippy_lints/src/misc.rs b/src/tools/clippy/clippy_lints/src/misc.rs
index 8224e80c9ccb..ea245edd7704 100644
--- a/src/tools/clippy/clippy_lints/src/misc.rs
+++ b/src/tools/clippy/clippy_lints/src/misc.rs
@@ -5,8 +5,8 @@ use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{
-    self as hir, def, BinOpKind, BindingAnnotation, Body, Expr, ExprKind, FnDecl, HirId, Mutability, PatKind, Stmt,
-    StmtKind, TyKind,
+    self as hir, def, BinOpKind, BindingAnnotation, Body, ByRef, Expr, ExprKind, FnDecl, HirId, Mutability, PatKind,
+    Stmt, StmtKind, TyKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
@@ -146,7 +146,7 @@ impl<'tcx> LateLintPass<'tcx> for MiscLints {
             return;
         }
         for arg in iter_input_pats(decl, body) {
-            if let PatKind::Binding(BindingAnnotation::Ref | BindingAnnotation::RefMut, ..) = arg.pat.kind {
+            if let PatKind::Binding(BindingAnnotation(ByRef::Yes, _), ..) = arg.pat.kind {
                 span_lint(
                     cx,
                     TOPLEVEL_REF_ARG,
@@ -162,9 +162,8 @@ impl<'tcx> LateLintPass<'tcx> for MiscLints {
         if_chain! {
             if !in_external_macro(cx.tcx.sess, stmt.span);
             if let StmtKind::Local(local) = stmt.kind;
-            if let PatKind::Binding(an, .., name, None) = local.pat.kind;
+            if let PatKind::Binding(BindingAnnotation(ByRef::Yes, mutabl), .., name, None) = local.pat.kind;
             if let Some(init) = local.init;
-            if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut;
             then {
                 // use the macro callsite when the init span (but not the whole local span)
                 // comes from an expansion like `vec![1, 2, 3]` in `let ref _ = vec![1, 2, 3];`
@@ -173,7 +172,7 @@ impl<'tcx> LateLintPass<'tcx> for MiscLints {
                 } else {
                     Sugg::hir(cx, init, "..")
                 };
-                let (mutopt, initref) = if an == BindingAnnotation::RefMut {
+                let (mutopt, initref) = if mutabl == Mutability::Mut {
                     ("mut ", sugg_init.mut_addr())
                 } else {
                     ("", sugg_init.addr())
diff --git a/src/tools/clippy/clippy_lints/src/misc_early/redundant_pattern.rs b/src/tools/clippy/clippy_lints/src/misc_early/redundant_pattern.rs
index 525dbf7757c1..d7bb0616acb0 100644
--- a/src/tools/clippy/clippy_lints/src/misc_early/redundant_pattern.rs
+++ b/src/tools/clippy/clippy_lints/src/misc_early/redundant_pattern.rs
@@ -1,18 +1,12 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use rustc_ast::ast::{BindingMode, Mutability, Pat, PatKind};
+use rustc_ast::ast::{Pat, PatKind};
 use rustc_errors::Applicability;
 use rustc_lint::EarlyContext;
 
 use super::REDUNDANT_PATTERN;
 
 pub(super) fn check(cx: &EarlyContext<'_>, pat: &Pat) {
-    if let PatKind::Ident(left, ident, Some(ref right)) = pat.kind {
-        let left_binding = match left {
-            BindingMode::ByRef(Mutability::Mut) => "ref mut ",
-            BindingMode::ByRef(Mutability::Not) => "ref ",
-            BindingMode::ByValue(..) => "",
-        };
-
+    if let PatKind::Ident(ann, ident, Some(ref right)) = pat.kind {
         if let PatKind::Wild = right.kind {
             span_lint_and_sugg(
                 cx,
@@ -23,7 +17,7 @@ pub(super) fn check(cx: &EarlyContext<'_>, pat: &Pat) {
                     ident.name, ident.name,
                 ),
                 "try",
-                format!("{}{}", left_binding, ident.name),
+                format!("{}{}", ann.prefix_str(), ident.name),
                 Applicability::MachineApplicable,
             );
         }
diff --git a/src/tools/clippy/clippy_lints/src/misc_early/unneeded_wildcard_pattern.rs b/src/tools/clippy/clippy_lints/src/misc_early/unneeded_wildcard_pattern.rs
index df044538fe19..7c4ae746e90e 100644
--- a/src/tools/clippy/clippy_lints/src/misc_early/unneeded_wildcard_pattern.rs
+++ b/src/tools/clippy/clippy_lints/src/misc_early/unneeded_wildcard_pattern.rs
@@ -46,7 +46,7 @@ fn span_lint(cx: &EarlyContext<'_>, span: Span, only_one: bool) {
             "these patterns are unneeded as the `..` pattern can match those elements"
         },
         if only_one { "remove it" } else { "remove them" },
-        "".to_string(),
+        String::new(),
         Applicability::MachineApplicable,
     );
 }
diff --git a/src/tools/clippy/clippy_lints/src/mismatching_type_param_order.rs b/src/tools/clippy/clippy_lints/src/mismatching_type_param_order.rs
index f763e0d24c94..020efeaebf02 100644
--- a/src/tools/clippy/clippy_lints/src/mismatching_type_param_order.rs
+++ b/src/tools/clippy/clippy_lints/src/mismatching_type_param_order.rs
@@ -40,7 +40,7 @@ declare_clippy_lint! {
     /// }
     /// impl<A, B> Foo<A, B> {}
     /// ```
-    #[clippy::version = "1.62.0"]
+    #[clippy::version = "1.63.0"]
     pub MISMATCHING_TYPE_PARAM_ORDER,
     pedantic,
     "type parameter positioned inconsistently between type def and impl block"
diff --git a/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs b/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
index bc304c081b90..f24b41411c81 100644
--- a/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
@@ -136,7 +136,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingConstForFn {
 
         // Const fns are not allowed as methods in a trait.
         {
-            let parent = cx.tcx.hir().get_parent_item(hir_id);
+            let parent = cx.tcx.hir().get_parent_item(hir_id).def_id;
             if parent != CRATE_DEF_ID {
                 if let hir::Node::Item(item) = cx.tcx.hir().get_by_def_id(parent) {
                     if let hir::ItemKind::Trait(..) = &item.kind {
diff --git a/src/tools/clippy/clippy_lints/src/missing_doc.rs b/src/tools/clippy/clippy_lints/src/missing_doc.rs
index 3701fdb4adbf..472195566768 100644
--- a/src/tools/clippy/clippy_lints/src/missing_doc.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_doc.rs
@@ -131,7 +131,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
             hir::ItemKind::Fn(..) => {
                 // ignore main()
                 if it.ident.name == sym::main {
-                    let at_root = cx.tcx.local_parent(it.def_id) == CRATE_DEF_ID;
+                    let at_root = cx.tcx.local_parent(it.def_id.def_id) == CRATE_DEF_ID;
                     if at_root {
                         return;
                     }
diff --git a/src/tools/clippy/clippy_lints/src/missing_inline.rs b/src/tools/clippy/clippy_lints/src/missing_inline.rs
index 07bc2ca5d3cd..9d5764ac0926 100644
--- a/src/tools/clippy/clippy_lints/src/missing_inline.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_inline.rs
@@ -88,7 +88,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingInline {
             return;
         }
 
-        if !cx.access_levels.is_exported(it.def_id) {
+        if !cx.access_levels.is_exported(it.def_id.def_id) {
             return;
         }
         match it.kind {
@@ -142,7 +142,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingInline {
         }
 
         // If the item being implemented is not exported, then we don't need #[inline]
-        if !cx.access_levels.is_exported(impl_item.def_id) {
+        if !cx.access_levels.is_exported(impl_item.def_id.def_id) {
             return;
         }
 
@@ -159,7 +159,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingInline {
         };
 
         if let Some(trait_def_id) = trait_def_id {
-            if trait_def_id.is_local() && !cx.access_levels.is_exported(impl_item.def_id) {
+            if trait_def_id.is_local() && !cx.access_levels.is_exported(impl_item.def_id.def_id) {
                 // If a trait is being implemented for an item, and the
                 // trait is not exported, we don't need #[inline]
                 return;
diff --git a/src/tools/clippy/clippy_lints/src/module_style.rs b/src/tools/clippy/clippy_lints/src/module_style.rs
index 0a393657267b..22071ab3044f 100644
--- a/src/tools/clippy/clippy_lints/src/module_style.rs
+++ b/src/tools/clippy/clippy_lints/src/module_style.rs
@@ -2,7 +2,7 @@ use rustc_ast::ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_lint::{EarlyContext, EarlyLintPass, Level, LintContext};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::{FileName, RealFileName, SourceFile, Span, SyntaxContext};
+use rustc_span::{FileName, SourceFile, Span, SyntaxContext};
 use std::ffi::OsStr;
 use std::path::{Component, Path};
 
@@ -79,7 +79,7 @@ impl EarlyLintPass for ModStyle {
 
         let files = cx.sess().source_map().files();
 
-        let RealFileName::LocalPath(trim_to_src) = &cx.sess().opts.working_dir else { return };
+        let Some(trim_to_src) = cx.sess().opts.working_dir.local_path() else { return };
 
         // `folder_segments` is all unique folder path segments `path/to/foo.rs` gives
         // `[path, to]` but not foo
@@ -90,7 +90,7 @@ impl EarlyLintPass for ModStyle {
         // `{ foo => path/to/foo.rs, .. }
         let mut file_map = FxHashMap::default();
         for file in files.iter() {
-            if let FileName::Real(RealFileName::LocalPath(lp)) = &file.name {
+            if let FileName::Real(name) = &file.name && let Some(lp) = name.local_path() {
                 let path = if lp.is_relative() {
                     lp
                 } else if let Ok(relative) = lp.strip_prefix(trim_to_src) {
diff --git a/src/tools/clippy/clippy_lints/src/multi_assignments.rs b/src/tools/clippy/clippy_lints/src/multi_assignments.rs
new file mode 100644
index 000000000000..81eb1a085aea
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/multi_assignments.rs
@@ -0,0 +1,65 @@
+use clippy_utils::diagnostics::span_lint;
+use rustc_ast::ast::{Expr, ExprKind, Stmt, StmtKind};
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for nested assignments.
+    ///
+    /// ### Why is this bad?
+    /// While this is in most cases already a type mismatch,
+    /// the result of an assignment being `()` can throw off people coming from languages like python or C,
+    /// where such assignments return a copy of the assigned value.
+    ///
+    /// ### Example
+    /// ```rust
+    ///# let (a, b);
+    /// a = b = 42;
+    /// ```
+    /// Use instead:
+    /// ```rust
+    ///# let (a, b);
+    /// b = 42;
+    /// a = b;
+    /// ```
+    #[clippy::version = "1.65.0"]
+    pub MULTI_ASSIGNMENTS,
+    suspicious,
+    "instead of using `a = b = c;` use `a = c; b = c;`"
+}
+
+declare_lint_pass!(MultiAssignments => [MULTI_ASSIGNMENTS]);
+
+fn strip_paren_blocks(expr: &Expr) -> &Expr {
+    match &expr.kind {
+        ExprKind::Paren(e) => strip_paren_blocks(e),
+        ExprKind::Block(b, _) => {
+            if let [
+                Stmt {
+                    kind: StmtKind::Expr(e),
+                    ..
+                },
+            ] = &b.stmts[..]
+            {
+                strip_paren_blocks(e)
+            } else {
+                expr
+            }
+        },
+        _ => expr,
+    }
+}
+
+impl EarlyLintPass for MultiAssignments {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
+        if let ExprKind::Assign(target, source, _) = &expr.kind {
+            if let ExprKind::Assign(_target, _source, _) = &strip_paren_blocks(target).kind {
+                span_lint(cx, MULTI_ASSIGNMENTS, expr.span, "assignments don't nest intuitively");
+            };
+            if let ExprKind::Assign(_target, _source, _) = &strip_paren_blocks(source).kind {
+                span_lint(cx, MULTI_ASSIGNMENTS, expr.span, "assignments don't nest intuitively");
+            }
+        };
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/mut_key.rs b/src/tools/clippy/clippy_lints/src/mut_key.rs
index 4db103bbc130..25d6ca83a94b 100644
--- a/src/tools/clippy/clippy_lints/src/mut_key.rs
+++ b/src/tools/clippy/clippy_lints/src/mut_key.rs
@@ -89,7 +89,7 @@ impl<'tcx> LateLintPass<'tcx> for MutableKeyType {
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'tcx>) {
         if let hir::ImplItemKind::Fn(ref sig, ..) = item.kind {
-            if trait_ref_of_method(cx, item.def_id).is_none() {
+            if trait_ref_of_method(cx, item.def_id.def_id).is_none() {
                 check_sig(cx, item.hir_id(), sig.decl);
             }
         }
diff --git a/src/tools/clippy/clippy_lints/src/mut_mutex_lock.rs b/src/tools/clippy/clippy_lints/src/mut_mutex_lock.rs
deleted file mode 100644
index b7f981faa2d4..000000000000
--- a/src/tools/clippy/clippy_lints/src/mut_mutex_lock.rs
+++ /dev/null
@@ -1,70 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::ty::is_type_diagnostic_item;
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, Mutability};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for `&mut Mutex::lock` calls
-    ///
-    /// ### Why is this bad?
-    /// `Mutex::lock` is less efficient than
-    /// calling `Mutex::get_mut`. In addition you also have a statically
-    /// guarantee that the mutex isn't locked, instead of just a runtime
-    /// guarantee.
-    ///
-    /// ### Example
-    /// ```rust
-    /// use std::sync::{Arc, Mutex};
-    ///
-    /// let mut value_rc = Arc::new(Mutex::new(42_u8));
-    /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
-    ///
-    /// let mut value = value_mutex.lock().unwrap();
-    /// *value += 1;
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// use std::sync::{Arc, Mutex};
-    ///
-    /// let mut value_rc = Arc::new(Mutex::new(42_u8));
-    /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
-    ///
-    /// let value = value_mutex.get_mut().unwrap();
-    /// *value += 1;
-    /// ```
-    #[clippy::version = "1.49.0"]
-    pub MUT_MUTEX_LOCK,
-    style,
-    "`&mut Mutex::lock` does unnecessary locking"
-}
-
-declare_lint_pass!(MutMutexLock => [MUT_MUTEX_LOCK]);
-
-impl<'tcx> LateLintPass<'tcx> for MutMutexLock {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, ex: &'tcx Expr<'tcx>) {
-        if_chain! {
-            if let ExprKind::MethodCall(path, [self_arg, ..], _) = &ex.kind;
-            if path.ident.name == sym!(lock);
-            let ty = cx.typeck_results().expr_ty(self_arg);
-            if let ty::Ref(_, inner_ty, Mutability::Mut) = ty.kind();
-            if is_type_diagnostic_item(cx, *inner_ty, sym::Mutex);
-            then {
-                span_lint_and_sugg(
-                    cx,
-                    MUT_MUTEX_LOCK,
-                    path.ident.span,
-                    "calling `&mut Mutex::lock` unnecessarily locks an exclusive (mutable) reference",
-                    "change this to",
-                    "get_mut".to_owned(),
-                    Applicability::MaybeIncorrect,
-                );
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/mut_reference.rs b/src/tools/clippy/clippy_lints/src/mut_reference.rs
index f434a655f8af..084c0d471dde 100644
--- a/src/tools/clippy/clippy_lints/src/mut_reference.rs
+++ b/src/tools/clippy/clippy_lints/src/mut_reference.rs
@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::span_lint;
 use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use std::iter;
@@ -43,18 +42,24 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryMutPassed {
                 if let ExprKind::Path(ref path) = fn_expr.kind {
                     check_arguments(
                         cx,
-                        arguments,
+                        arguments.iter().collect(),
                         cx.typeck_results().expr_ty(fn_expr),
                         &rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false)),
                         "function",
                     );
                 }
             },
-            ExprKind::MethodCall(path, arguments, _) => {
+            ExprKind::MethodCall(path, receiver, arguments, _) => {
                 let def_id = cx.typeck_results().type_dependent_def_id(e.hir_id).unwrap();
                 let substs = cx.typeck_results().node_substs(e.hir_id);
                 let method_type = cx.tcx.bound_type_of(def_id).subst(cx.tcx, substs);
-                check_arguments(cx, arguments, method_type, path.ident.as_str(), "method");
+                check_arguments(
+                    cx,
+                    std::iter::once(receiver).chain(arguments.iter()).collect(),
+                    method_type,
+                    path.ident.as_str(),
+                    "method",
+                );
             },
             _ => (),
         }
@@ -63,7 +68,7 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryMutPassed {
 
 fn check_arguments<'tcx>(
     cx: &LateContext<'tcx>,
-    arguments: &[Expr<'_>],
+    arguments: Vec<&Expr<'_>>,
     type_definition: Ty<'tcx>,
     name: &str,
     fn_kind: &str,
diff --git a/src/tools/clippy/clippy_lints/src/needless_arbitrary_self_type.rs b/src/tools/clippy/clippy_lints/src/needless_arbitrary_self_type.rs
index 9838d3cad9f0..f2ffac85bf40 100644
--- a/src/tools/clippy/clippy_lints/src/needless_arbitrary_self_type.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_arbitrary_self_type.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use if_chain::if_chain;
-use rustc_ast::ast::{BindingMode, Lifetime, Mutability, Param, PatKind, Path, TyKind};
+use rustc_ast::ast::{BindingAnnotation, ByRef, Lifetime, Mutability, Param, PatKind, Path, TyKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -120,14 +120,14 @@ impl EarlyLintPass for NeedlessArbitrarySelfType {
 
         match &p.ty.kind {
             TyKind::Path(None, path) => {
-                if let PatKind::Ident(BindingMode::ByValue(mutbl), _, _) = p.pat.kind {
+                if let PatKind::Ident(BindingAnnotation(ByRef::No, mutbl), _, _) = p.pat.kind {
                     check_param_inner(cx, path, p.span.to(p.ty.span), &Mode::Value, mutbl);
                 }
             },
             TyKind::Rptr(lifetime, mut_ty) => {
                 if_chain! {
                 if let TyKind::Path(None, path) = &mut_ty.ty.kind;
-                if let PatKind::Ident(BindingMode::ByValue(Mutability::Not), _, _) = p.pat.kind;
+                if let PatKind::Ident(BindingAnnotation::NONE, _, _) = p.pat.kind;
                     then {
                         check_param_inner(cx, path, p.span.to(p.ty.span), &Mode::Ref(*lifetime), mut_ty.mutbl);
                     }
diff --git a/src/tools/clippy/clippy_lints/src/needless_borrowed_ref.rs b/src/tools/clippy/clippy_lints/src/needless_borrowed_ref.rs
index 05c012b92e87..b8855e5adbff 100644
--- a/src/tools/clippy/clippy_lints/src/needless_borrowed_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_borrowed_ref.rs
@@ -59,7 +59,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessBorrowedRef {
             if let PatKind::Ref(sub_pat, Mutability::Not) = pat.kind;
 
             // Check sub_pat got a `ref` keyword (excluding `ref mut`).
-            if let PatKind::Binding(BindingAnnotation::Ref, .., spanned_name, _) = sub_pat.kind;
+            if let PatKind::Binding(BindingAnnotation::REF, .., spanned_name, _) = sub_pat.kind;
             let parent_id = cx.tcx.hir().get_parent_node(pat.hir_id);
             if let Some(parent_node) = cx.tcx.hir().find(parent_id);
             then {
diff --git a/src/tools/clippy/clippy_lints/src/needless_for_each.rs b/src/tools/clippy/clippy_lints/src/needless_for_each.rs
index 10e188ecb79a..3233d87c0731 100644
--- a/src/tools/clippy/clippy_lints/src/needless_for_each.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_for_each.rs
@@ -56,12 +56,12 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessForEach {
 
         if_chain! {
             // Check the method name is `for_each`.
-            if let ExprKind::MethodCall(method_name, [for_each_recv, for_each_arg], _) = expr.kind;
+            if let ExprKind::MethodCall(method_name, for_each_recv, [for_each_arg], _) = expr.kind;
             if method_name.ident.name == Symbol::intern("for_each");
             // Check `for_each` is an associated function of `Iterator`.
             if is_trait_method(cx, expr, sym::Iterator);
             // Checks the receiver of `for_each` is also a method call.
-            if let ExprKind::MethodCall(_, [iter_recv], _) = for_each_recv.kind;
+            if let ExprKind::MethodCall(_, iter_recv, [], _) = for_each_recv.kind;
             // Skip the lint if the call chain is too long. e.g. `v.field.iter().for_each()` or
             // `v.foo().iter().for_each()` must be skipped.
             if matches!(
@@ -77,7 +77,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessForEach {
             if let ExprKind::Block(..) = body.value.kind;
             then {
                 let mut ret_collector = RetCollector::default();
-                ret_collector.visit_expr(&body.value);
+                ret_collector.visit_expr(body.value);
 
                 // Skip the lint if `return` is used in `Loop` in order not to suggest using `'label`.
                 if ret_collector.ret_in_loop {
diff --git a/src/tools/clippy/clippy_lints/src/needless_late_init.rs b/src/tools/clippy/clippy_lints/src/needless_late_init.rs
index ff2999b1f4a5..de99f1d7078e 100644
--- a/src/tools/clippy/clippy_lints/src/needless_late_init.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_late_init.rs
@@ -373,7 +373,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessLateInit {
             if let Local {
                 init: None,
                 pat: &Pat {
-                    kind: PatKind::Binding(BindingAnnotation::Unannotated, binding_id, _, None),
+                    kind: PatKind::Binding(BindingAnnotation::NONE, binding_id, _, None),
                     ..
                 },
                 source: LocalSource::Normal,
diff --git a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
index 0cbef1c95fe9..060037ed4969 100644
--- a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
@@ -8,7 +8,9 @@ use rustc_ast::ast::Attribute;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_hir::intravisit::FnKind;
-use rustc_hir::{BindingAnnotation, Body, FnDecl, GenericArg, HirId, Impl, ItemKind, Node, PatKind, QPath, TyKind};
+use rustc_hir::{
+    BindingAnnotation, Body, FnDecl, GenericArg, HirId, Impl, ItemKind, Mutability, Node, PatKind, QPath, TyKind,
+};
 use rustc_hir::{HirIdMap, HirIdSet};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
@@ -171,7 +173,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
                 (
                     preds.iter().any(|t| cx.tcx.is_diagnostic_item(sym::Borrow, t.def_id())),
                     !preds.is_empty() && {
-                        let ty_empty_region = cx.tcx.mk_imm_ref(cx.tcx.lifetimes.re_root_empty, ty);
+                        let ty_empty_region = cx.tcx.mk_imm_ref(cx.tcx.lifetimes.re_erased, ty);
                         preds.iter().all(|t| {
                             let ty_params = t.trait_ref.substs.iter().skip(1).collect::<Vec<_>>();
                             implements_trait(cx, ty_empty_region, t.def_id(), &ty_params)
@@ -188,13 +190,9 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
                 if !implements_borrow_trait;
                 if !all_borrowable_trait;
 
-                if let PatKind::Binding(mode, canonical_id, ..) = arg.pat.kind;
+                if let PatKind::Binding(BindingAnnotation(_, Mutability::Not), canonical_id, ..) = arg.pat.kind;
                 if !moved_vars.contains(&canonical_id);
                 then {
-                    if mode == BindingAnnotation::Mutable || mode == BindingAnnotation::RefMut {
-                        continue;
-                    }
-
                     // Dereference suggestion
                     let sugg = |diag: &mut Diagnostic| {
                         if let ty::Adt(def, ..) = ty.kind() {
diff --git a/src/tools/clippy/clippy_lints/src/new_without_default.rs b/src/tools/clippy/clippy_lints/src/new_without_default.rs
index 5c45ee6d94ad..357a71693d2c 100644
--- a/src/tools/clippy/clippy_lints/src/new_without_default.rs
+++ b/src/tools/clippy/clippy_lints/src/new_without_default.rs
@@ -84,7 +84,7 @@ impl<'tcx> LateLintPass<'tcx> for NewWithoutDefault {
                             // can't be implemented for unsafe new
                             return;
                         }
-                        if cx.tcx.is_doc_hidden(impl_item.def_id) {
+                        if cx.tcx.is_doc_hidden(impl_item.def_id.def_id) {
                             // shouldn't be implemented when it is hidden in docs
                             return;
                         }
@@ -96,7 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for NewWithoutDefault {
                         if_chain! {
                             if sig.decl.inputs.is_empty();
                             if name == sym::new;
-                            if cx.access_levels.is_reachable(impl_item.def_id);
+                            if cx.access_levels.is_reachable(impl_item.def_id.def_id);
                             let self_def_id = cx.tcx.hir().get_parent_item(id);
                             let self_ty = cx.tcx.type_of(self_def_id);
                             if self_ty == return_ty(cx, id);
diff --git a/src/tools/clippy/clippy_lints/src/non_copy_const.rs b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
index 72c86f28bbc6..616ef9e2f867 100644
--- a/src/tools/clippy/clippy_lints/src/non_copy_const.rs
+++ b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
@@ -195,7 +195,7 @@ fn is_value_unfrozen_expr<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId, def_id: D
 
     let result = cx.tcx.const_eval_resolve(
         cx.param_env,
-        ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs),
+        mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs),
         None,
     );
     is_value_unfrozen_raw(cx, result, ty)
@@ -286,7 +286,7 @@ impl<'tcx> LateLintPass<'tcx> for NonCopyConst {
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx ImplItem<'_>) {
         if let ImplItemKind::Const(hir_ty, body_id) = &impl_item.kind {
-            let item_def_id = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+            let item_def_id = cx.tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
             let item = cx.tcx.hir().expect_item(item_def_id);
 
             match &item.kind {
diff --git a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
index b96af06b8d7c..a7cd1f6d0652 100644
--- a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
+++ b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
@@ -15,6 +15,10 @@ declare_clippy_lint! {
     /// ### What it does
     /// Checks for names that are very similar and thus confusing.
     ///
+    /// Note: this lint looks for similar names throughout each
+    /// scope. To allow it, you need to allow it on the scope
+    /// level, not on the name that is reported.
+    ///
     /// ### Why is this bad?
     /// It's hard to distinguish between names that differ only
     /// by a single character.
diff --git a/src/tools/clippy/clippy_lints/src/non_octal_unix_permissions.rs b/src/tools/clippy/clippy_lints/src/non_octal_unix_permissions.rs
index ed022b9d5291..25fb4f0f4cff 100644
--- a/src/tools/clippy/clippy_lints/src/non_octal_unix_permissions.rs
+++ b/src/tools/clippy/clippy_lints/src/non_octal_unix_permissions.rs
@@ -43,7 +43,7 @@ declare_lint_pass!(NonOctalUnixPermissions => [NON_OCTAL_UNIX_PERMISSIONS]);
 impl<'tcx> LateLintPass<'tcx> for NonOctalUnixPermissions {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         match &expr.kind {
-            ExprKind::MethodCall(path, [func, param], _) => {
+            ExprKind::MethodCall(path, func, [param], _) => {
                 let obj_ty = cx.typeck_results().expr_ty(func).peel_refs();
 
                 if_chain! {
diff --git a/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs b/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs
index 4722c031006b..f86dfb6b8df8 100644
--- a/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs
+++ b/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs
@@ -184,6 +184,10 @@ fn macro_braces(conf: FxHashSet<MacroMatcher>) -> FxHashMap<String, (String, Str
             name: "vec",
             braces: ("[", "]"),
         ),
+        macro_matcher!(
+            name: "matches",
+            braces: ("(", ")"),
+        ),
     ]
     .into_iter()
     .collect::<FxHashMap<_, _>>();
diff --git a/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs b/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs
index 413a740be25a..d64a9cf71e17 100644
--- a/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs
+++ b/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs
@@ -1,26 +1,18 @@
-use std::collections::VecDeque;
-
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::is_lint_allowed;
-use itertools::{izip, Itertools};
-use rustc_ast::{walk_list, Label, Mutability};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::{get_expr_use_or_unification_node, get_parent_node, path_def_id, path_to_local, path_to_local_id};
+use core::cell::Cell;
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::Applicability;
-use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::DefId;
-use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
-use rustc_hir::intravisit::{walk_expr, walk_stmt, FnKind, Visitor};
-use rustc_hir::{
-    Arm, Block, Body, Closure, Expr, ExprKind, Guard, HirId, ImplicitSelfKind, Let, Local, Pat, PatKind, Path,
-    PathSegment, QPath, Stmt, StmtKind, TyKind, UnOp,
-};
+use rustc_hir::hir_id::HirIdMap;
+use rustc_hir::{Body, Expr, ExprKind, HirId, ImplItem, ImplItemKind, Node, PatKind, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty;
-use rustc_middle::ty::{Ty, TyCtxt, TypeckResults};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::symbol::kw;
-use rustc_span::symbol::Ident;
+use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
+use rustc_middle::ty::{self, ConstKind};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::{kw, Ident};
 use rustc_span::Span;
+use std::iter;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -89,572 +81,315 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.61.0"]
     pub ONLY_USED_IN_RECURSION,
-    nursery,
+    complexity,
     "arguments that is only used in recursion can be removed"
 }
-declare_lint_pass!(OnlyUsedInRecursion => [ONLY_USED_IN_RECURSION]);
+impl_lint_pass!(OnlyUsedInRecursion => [ONLY_USED_IN_RECURSION]);
+
+#[derive(Clone, Copy)]
+enum FnKind {
+    Fn,
+    TraitFn,
+    // This is a hack. Ideally we would store a `SubstsRef<'tcx>` type here, but a lint pass must be `'static`.
+    // Substitutions are, however, interned. This allows us to store the pointer as a `usize` when comparing for
+    // equality.
+    ImplTraitFn(usize),
+}
+
+struct Param {
+    /// The function this is a parameter for.
+    fn_id: DefId,
+    fn_kind: FnKind,
+    /// The index of this parameter.
+    idx: usize,
+    ident: Ident,
+    /// Whether this parameter should be linted. Set by `Params::flag_for_linting`.
+    apply_lint: Cell<bool>,
+    /// All the uses of this parameter.
+    uses: Vec<Usage>,
+}
+impl Param {
+    fn new(fn_id: DefId, fn_kind: FnKind, idx: usize, ident: Ident) -> Self {
+        Self {
+            fn_id,
+            fn_kind,
+            idx,
+            ident,
+            apply_lint: Cell::new(true),
+            uses: Vec::new(),
+        }
+    }
+}
+
+#[derive(Debug)]
+struct Usage {
+    span: Span,
+    idx: usize,
+}
+impl Usage {
+    fn new(span: Span, idx: usize) -> Self {
+        Self { span, idx }
+    }
+}
+
+/// The parameters being checked by the lint, indexed by both the parameter's `HirId` and the
+/// `DefId` of the function paired with the parameter's index.
+#[derive(Default)]
+struct Params {
+    params: Vec<Param>,
+    by_id: HirIdMap<usize>,
+    by_fn: FxHashMap<(DefId, usize), usize>,
+}
+impl Params {
+    fn insert(&mut self, param: Param, id: HirId) {
+        let idx = self.params.len();
+        self.by_id.insert(id, idx);
+        self.by_fn.insert((param.fn_id, param.idx), idx);
+        self.params.push(param);
+    }
+
+    fn remove_by_id(&mut self, id: HirId) {
+        if let Some(param) = self.get_by_id_mut(id) {
+            param.uses = Vec::new();
+            let key = (param.fn_id, param.idx);
+            self.by_fn.remove(&key);
+            self.by_id.remove(&id);
+        }
+    }
+
+    fn get_by_id_mut(&mut self, id: HirId) -> Option<&mut Param> {
+        self.params.get_mut(*self.by_id.get(&id)?)
+    }
+
+    fn get_by_fn(&self, id: DefId, idx: usize) -> Option<&Param> {
+        self.params.get(*self.by_fn.get(&(id, idx))?)
+    }
+
+    fn clear(&mut self) {
+        self.params.clear();
+        self.by_id.clear();
+        self.by_fn.clear();
+    }
+
+    /// Sets the `apply_lint` flag on each parameter.
+    fn flag_for_linting(&mut self) {
+        // Stores the list of parameters currently being resolved. Needed to avoid cycles.
+        let mut eval_stack = Vec::new();
+        for param in &self.params {
+            self.try_disable_lint_for_param(param, &mut eval_stack);
+        }
+    }
+
+    // Use by calling `flag_for_linting`.
+    fn try_disable_lint_for_param(&self, param: &Param, eval_stack: &mut Vec<usize>) -> bool {
+        if !param.apply_lint.get() {
+            true
+        } else if param.uses.is_empty() {
+            // Don't lint on unused parameters.
+            param.apply_lint.set(false);
+            true
+        } else if eval_stack.contains(&param.idx) {
+            // Already on the evaluation stack. Returning false will continue to evaluate other dependencies.
+            false
+        } else {
+            eval_stack.push(param.idx);
+            // Check all cases when used at a different parameter index.
+            // Needed to catch cases like: `fn f(x: u32, y: u32) { f(y, x) }`
+            for usage in param.uses.iter().filter(|u| u.idx != param.idx) {
+                if self
+                    .get_by_fn(param.fn_id, usage.idx)
+                    // If the parameter can't be found, then it's used for more than just recursion.
+                    .map_or(true, |p| self.try_disable_lint_for_param(p, eval_stack))
+                {
+                    param.apply_lint.set(false);
+                    eval_stack.pop();
+                    return true;
+                }
+            }
+            eval_stack.pop();
+            false
+        }
+    }
+}
+
+#[derive(Default)]
+pub struct OnlyUsedInRecursion {
+    /// Track the top-level body entered. Needed to delay reporting when entering nested bodies.
+    entered_body: Option<HirId>,
+    params: Params,
+}
 
 impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion {
-    fn check_fn(
-        &mut self,
-        cx: &LateContext<'tcx>,
-        kind: FnKind<'tcx>,
-        decl: &'tcx rustc_hir::FnDecl<'tcx>,
-        body: &'tcx Body<'tcx>,
-        _: Span,
-        id: HirId,
-    ) {
-        if is_lint_allowed(cx, ONLY_USED_IN_RECURSION, id) {
+    fn check_body(&mut self, cx: &LateContext<'tcx>, body: &'tcx Body<'tcx>) {
+        if body.value.span.from_expansion() {
             return;
         }
-        if let FnKind::ItemFn(ident, ..) | FnKind::Method(ident, ..) = kind {
-            let def_id = id.owner.to_def_id();
-            let data = cx.tcx.def_path(def_id).data;
-
-            if data.len() > 1 {
-                match data.get(data.len() - 2) {
-                    Some(DisambiguatedDefPathData {
-                        data: DefPathData::Impl,
-                        disambiguator,
-                    }) if *disambiguator != 0 => return,
-                    _ => {},
-                }
-            }
-
-            let has_self = !matches!(decl.implicit_self, ImplicitSelfKind::None);
-
-            let ty_res = cx.typeck_results();
-            let param_span = body
-                .params
-                .iter()
-                .flat_map(|param| {
-                    let mut v = Vec::new();
-                    param.pat.each_binding(|_, hir_id, span, ident| {
-                        v.push((hir_id, span, ident));
-                    });
-                    v
-                })
-                .skip(if has_self { 1 } else { 0 })
-                .filter(|(_, _, ident)| !ident.name.as_str().starts_with('_'))
-                .collect_vec();
-
-            let params = body.params.iter().map(|param| param.pat).collect();
-
-            let mut visitor = SideEffectVisit {
-                graph: FxHashMap::default(),
-                has_side_effect: FxHashSet::default(),
-                ret_vars: Vec::new(),
-                contains_side_effect: false,
-                break_vars: FxHashMap::default(),
-                params,
-                fn_ident: ident,
-                fn_def_id: def_id,
-                is_method: matches!(kind, FnKind::Method(..)),
-                has_self,
-                ty_res,
-                tcx: cx.tcx,
-                visited_exprs: FxHashSet::default(),
-            };
-
-            visitor.visit_expr(&body.value);
-            let vars = std::mem::take(&mut visitor.ret_vars);
-            // this would set the return variables to side effect
-            visitor.add_side_effect(vars);
-
-            let mut queue = visitor.has_side_effect.iter().copied().collect::<VecDeque<_>>();
-
-            // a simple BFS to check all the variables that have side effect
-            while let Some(id) = queue.pop_front() {
-                if let Some(next) = visitor.graph.get(&id) {
-                    for i in next {
-                        if !visitor.has_side_effect.contains(i) {
-                            visitor.has_side_effect.insert(*i);
-                            queue.push_back(*i);
-                        }
-                    }
-                }
-            }
-
-            for (id, span, ident) in param_span {
-                // if the variable is not used in recursion, it would be marked as unused
-                if !visitor.has_side_effect.contains(&id) {
-                    let mut queue = VecDeque::new();
-                    let mut visited = FxHashSet::default();
-
-                    queue.push_back(id);
-
-                    // a simple BFS to check the graph can reach to itself
-                    // if it can't, it means the variable is never used in recursion
-                    while let Some(id) = queue.pop_front() {
-                        if let Some(next) = visitor.graph.get(&id) {
-                            for i in next {
-                                if !visited.contains(i) {
-                                    visited.insert(id);
-                                    queue.push_back(*i);
-                                }
-                            }
-                        }
-                    }
-
-                    if visited.contains(&id) {
-                        span_lint_and_sugg(
-                            cx,
-                            ONLY_USED_IN_RECURSION,
-                            span,
-                            "parameter is only used in recursion",
-                            "if this is intentional, prefix with an underscore",
-                            format!("_{}", ident.name.as_str()),
-                            Applicability::MaybeIncorrect,
-                        );
-                    }
-                }
-            }
-        }
-    }
-}
-
-pub fn is_primitive(ty: Ty<'_>) -> bool {
-    let ty = ty.peel_refs();
-    ty.is_primitive() || ty.is_str()
-}
-
-pub fn is_array(ty: Ty<'_>) -> bool {
-    let ty = ty.peel_refs();
-    ty.is_array() || ty.is_array_slice()
-}
-
-/// This builds the graph of side effect.
-/// The edge `a -> b` means if `a` has side effect, `b` will have side effect.
-///
-/// There are some example in following code:
-/// ```rust, ignore
-/// let b = 1;
-/// let a = b; // a -> b
-/// let (c, d) = (a, b); // c -> b, d -> b
-///
-/// let e = if a == 0 { // e -> a
-///     c // e -> c
-/// } else {
-///     d // e -> d
-/// };
-/// ```
-pub struct SideEffectVisit<'tcx> {
-    graph: FxHashMap<HirId, FxHashSet<HirId>>,
-    has_side_effect: FxHashSet<HirId>,
-    // bool for if the variable was dereferenced from mutable reference
-    ret_vars: Vec<(HirId, bool)>,
-    contains_side_effect: bool,
-    // break label
-    break_vars: FxHashMap<Ident, Vec<(HirId, bool)>>,
-    params: Vec<&'tcx Pat<'tcx>>,
-    fn_ident: Ident,
-    fn_def_id: DefId,
-    is_method: bool,
-    has_self: bool,
-    ty_res: &'tcx TypeckResults<'tcx>,
-    tcx: TyCtxt<'tcx>,
-    visited_exprs: FxHashSet<HirId>,
-}
-
-impl<'tcx> Visitor<'tcx> for SideEffectVisit<'tcx> {
-    fn visit_stmt(&mut self, s: &'tcx Stmt<'tcx>) {
-        match s.kind {
-            StmtKind::Local(Local {
-                pat, init: Some(init), ..
-            }) => {
-                self.visit_pat_expr(pat, init, false);
-            },
-            StmtKind::Item(_) | StmtKind::Expr(_) | StmtKind::Semi(_) => {
-                walk_stmt(self, s);
-            },
-            StmtKind::Local(_) => {},
-        }
-        self.ret_vars.clear();
-    }
-
-    fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
-        if !self.visited_exprs.insert(ex.hir_id) {
-            return;
-        }
-        match ex.kind {
-            ExprKind::Array(exprs) | ExprKind::Tup(exprs) => {
-                self.ret_vars = exprs
-                    .iter()
-                    .flat_map(|expr| {
-                        self.visit_expr(expr);
-                        std::mem::take(&mut self.ret_vars)
-                    })
-                    .collect();
-            },
-            ExprKind::Call(callee, args) => self.visit_fn(callee, args),
-            ExprKind::MethodCall(path, args, _) => self.visit_method_call(path, args),
-            ExprKind::Binary(_, lhs, rhs) => {
-                self.visit_bin_op(lhs, rhs);
-            },
-            ExprKind::Unary(op, expr) => self.visit_un_op(op, expr),
-            ExprKind::Let(Let { pat, init, .. }) => self.visit_pat_expr(pat, init, false),
-            ExprKind::If(bind, then_expr, else_expr) => {
-                self.visit_if(bind, then_expr, else_expr);
-            },
-            ExprKind::Match(expr, arms, _) => self.visit_match(expr, arms),
-            // since analysing the closure is not easy, just set all variables in it to side-effect
-            ExprKind::Closure(&Closure { body, .. }) => {
-                let body = self.tcx.hir().body(body);
-                self.visit_body(body);
-                let vars = std::mem::take(&mut self.ret_vars);
-                self.add_side_effect(vars);
-            },
-            ExprKind::Loop(block, label, _, _) | ExprKind::Block(block, label) => {
-                self.visit_block_label(block, label);
-            },
-            ExprKind::Assign(bind, expr, _) => {
-                self.visit_assign(bind, expr);
-            },
-            ExprKind::AssignOp(_, bind, expr) => {
-                self.visit_assign(bind, expr);
-                self.visit_bin_op(bind, expr);
-            },
-            ExprKind::Field(expr, _) => {
-                self.visit_expr(expr);
-                if matches!(self.ty_res.expr_ty(expr).kind(), ty::Ref(_, _, Mutability::Mut)) {
-                    self.ret_vars.iter_mut().for_each(|(_, b)| *b = true);
+        // `skip_params` is either `0` or `1` to skip the `self` parameter in trait functions.
+        // It can't be renamed, and it can't be removed without removing it from multiple functions.
+        let (fn_id, fn_kind, skip_params) = match get_parent_node(cx.tcx, body.value.hir_id) {
+            Some(Node::Item(i)) => (i.def_id.to_def_id(), FnKind::Fn, 0),
+            Some(Node::TraitItem(&TraitItem {
+                kind: TraitItemKind::Fn(ref sig, _),
+                def_id,
+                ..
+            })) => (
+                def_id.to_def_id(),
+                FnKind::TraitFn,
+                usize::from(sig.decl.implicit_self.has_implicit_self()),
+            ),
+            Some(Node::ImplItem(&ImplItem {
+                kind: ImplItemKind::Fn(ref sig, _),
+                def_id,
+                ..
+            })) => {
+                #[allow(trivial_casts)]
+                if let Some(Node::Item(item)) = get_parent_node(cx.tcx, def_id.into())
+                    && let Some(trait_ref) = cx.tcx.impl_trait_ref(item.def_id)
+                    && let Some(trait_item_id) = cx.tcx.associated_item(def_id).trait_item_def_id
+                {
+                    (
+                        trait_item_id,
+                        FnKind::ImplTraitFn(cx.tcx.erase_regions(trait_ref.substs) as *const _ as usize),
+                        usize::from(sig.decl.implicit_self.has_implicit_self()),
+                    )
+                } else {
+                    (def_id.to_def_id(), FnKind::Fn, 0)
                 }
             },
-            ExprKind::Index(expr, index) => {
-                self.visit_expr(expr);
-                let mut vars = std::mem::take(&mut self.ret_vars);
-                self.visit_expr(index);
-                self.ret_vars.append(&mut vars);
-
-                if !is_array(self.ty_res.expr_ty(expr)) {
-                    self.add_side_effect(self.ret_vars.clone());
-                } else if matches!(self.ty_res.expr_ty(expr).kind(), ty::Ref(_, _, Mutability::Mut)) {
-                    self.ret_vars.iter_mut().for_each(|(_, b)| *b = true);
-                }
-            },
-            ExprKind::Break(dest, Some(expr)) => {
-                self.visit_expr(expr);
-                if let Some(label) = dest.label {
-                    self.break_vars
-                        .entry(label.ident)
-                        .or_insert(Vec::new())
-                        .append(&mut self.ret_vars);
-                }
-                self.contains_side_effect = true;
-            },
-            ExprKind::Ret(Some(expr)) => {
-                self.visit_expr(expr);
-                let vars = std::mem::take(&mut self.ret_vars);
-                self.add_side_effect(vars);
-                self.contains_side_effect = true;
-            },
-            ExprKind::Break(_, None) | ExprKind::Continue(_) | ExprKind::Ret(None) => {
-                self.contains_side_effect = true;
-            },
-            ExprKind::Struct(_, exprs, expr) => {
-                let mut ret_vars = exprs
-                    .iter()
-                    .flat_map(|field| {
-                        self.visit_expr(field.expr);
-                        std::mem::take(&mut self.ret_vars)
-                    })
-                    .collect();
-
-                walk_list!(self, visit_expr, expr);
-                self.ret_vars.append(&mut ret_vars);
-            },
-            _ => walk_expr(self, ex),
-        }
-    }
-
-    fn visit_path(&mut self, path: &'tcx Path<'tcx>, _id: HirId) {
-        if let Res::Local(id) = path.res {
-            self.ret_vars.push((id, false));
-        }
-    }
-}
-
-impl<'tcx> SideEffectVisit<'tcx> {
-    fn visit_assign(&mut self, lhs: &'tcx Expr<'tcx>, rhs: &'tcx Expr<'tcx>) {
-        // Just support array and tuple unwrapping for now.
-        //
-        // ex) `(a, b) = (c, d);`
-        // The graph would look like this:
-        //   a -> c
-        //   b -> d
-        //
-        // This would minimize the connection of the side-effect graph.
-        match (&lhs.kind, &rhs.kind) {
-            (ExprKind::Array(lhs), ExprKind::Array(rhs)) | (ExprKind::Tup(lhs), ExprKind::Tup(rhs)) => {
-                // if not, it is a compile error
-                debug_assert!(lhs.len() == rhs.len());
-                izip!(*lhs, *rhs).for_each(|(lhs, rhs)| self.visit_assign(lhs, rhs));
-            },
-            // in other assigns, we have to connect all each other
-            // because they can be connected somehow
-            _ => {
-                self.visit_expr(lhs);
-                let lhs_vars = std::mem::take(&mut self.ret_vars);
-                self.visit_expr(rhs);
-                let rhs_vars = std::mem::take(&mut self.ret_vars);
-                self.connect_assign(&lhs_vars, &rhs_vars, false);
-            },
-        }
-    }
-
-    fn visit_block_label(&mut self, block: &'tcx Block<'tcx>, label: Option<Label>) {
-        self.visit_block(block);
-        let _ = label.and_then(|label| {
-            self.break_vars
-                .remove(&label.ident)
-                .map(|mut break_vars| self.ret_vars.append(&mut break_vars))
-        });
-    }
-
-    fn visit_bin_op(&mut self, lhs: &'tcx Expr<'tcx>, rhs: &'tcx Expr<'tcx>) {
-        self.visit_expr(lhs);
-        let mut ret_vars = std::mem::take(&mut self.ret_vars);
-        self.visit_expr(rhs);
-        self.ret_vars.append(&mut ret_vars);
-
-        // the binary operation between non primitive values are overloaded operators
-        // so they can have side-effects
-        if !is_primitive(self.ty_res.expr_ty(lhs)) || !is_primitive(self.ty_res.expr_ty(rhs)) {
-            self.ret_vars.iter().for_each(|id| {
-                self.has_side_effect.insert(id.0);
-            });
-            self.contains_side_effect = true;
-        }
-    }
-
-    fn visit_un_op(&mut self, op: UnOp, expr: &'tcx Expr<'tcx>) {
-        self.visit_expr(expr);
-        let ty = self.ty_res.expr_ty(expr);
-        // dereferencing a reference has no side-effect
-        if !is_primitive(ty) && !matches!((op, ty.kind()), (UnOp::Deref, ty::Ref(..))) {
-            self.add_side_effect(self.ret_vars.clone());
-        }
-
-        if matches!((op, ty.kind()), (UnOp::Deref, ty::Ref(_, _, Mutability::Mut))) {
-            self.ret_vars.iter_mut().for_each(|(_, b)| *b = true);
-        }
-    }
-
-    fn visit_pat_expr(&mut self, pat: &'tcx Pat<'tcx>, expr: &'tcx Expr<'tcx>, connect_self: bool) {
-        match (&pat.kind, &expr.kind) {
-            (PatKind::Tuple(pats, _), ExprKind::Tup(exprs)) => {
-                self.ret_vars = izip!(*pats, *exprs)
-                    .flat_map(|(pat, expr)| {
-                        self.visit_pat_expr(pat, expr, connect_self);
-                        std::mem::take(&mut self.ret_vars)
-                    })
-                    .collect();
-            },
-            (PatKind::Slice(front_exprs, _, back_exprs), ExprKind::Array(exprs)) => {
-                let mut vars = izip!(*front_exprs, *exprs)
-                    .flat_map(|(pat, expr)| {
-                        self.visit_pat_expr(pat, expr, connect_self);
-                        std::mem::take(&mut self.ret_vars)
-                    })
-                    .collect();
-                self.ret_vars = izip!(back_exprs.iter().rev(), exprs.iter().rev())
-                    .flat_map(|(pat, expr)| {
-                        self.visit_pat_expr(pat, expr, connect_self);
-                        std::mem::take(&mut self.ret_vars)
-                    })
-                    .collect();
-                self.ret_vars.append(&mut vars);
-            },
-            _ => {
-                let mut lhs_vars = Vec::new();
-                pat.each_binding(|_, id, _, _| lhs_vars.push((id, false)));
-                self.visit_expr(expr);
-                let rhs_vars = std::mem::take(&mut self.ret_vars);
-                self.connect_assign(&lhs_vars, &rhs_vars, connect_self);
-                self.ret_vars = rhs_vars;
-            },
-        }
-    }
-
-    fn visit_fn(&mut self, callee: &'tcx Expr<'tcx>, args: &'tcx [Expr<'tcx>]) {
-        self.visit_expr(callee);
-        let mut ret_vars = std::mem::take(&mut self.ret_vars);
-        self.add_side_effect(ret_vars.clone());
-
-        let mut is_recursive = false;
-
-        if_chain! {
-            if !self.has_self;
-            if let ExprKind::Path(QPath::Resolved(_, path)) = callee.kind;
-            if let Res::Def(DefKind::Fn, def_id) = path.res;
-            if self.fn_def_id == def_id;
-            then {
-                is_recursive = true;
-            }
-        }
-
-        if_chain! {
-            if !self.has_self && self.is_method;
-            if let ExprKind::Path(QPath::TypeRelative(ty, segment)) = callee.kind;
-            if segment.ident == self.fn_ident;
-            if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
-            if let Res::SelfTy{ .. } = path.res;
-            then {
-                is_recursive = true;
-            }
-        }
-
-        if is_recursive {
-            izip!(self.params.clone(), args).for_each(|(pat, expr)| {
-                self.visit_pat_expr(pat, expr, true);
-                self.ret_vars.clear();
-            });
-        } else {
-            // This would set arguments used in closure that does not have side-effect.
-            // Closure itself can be detected whether there is a side-effect, but the
-            // value of variable that is holding closure can change.
-            // So, we just check the variables.
-            self.ret_vars = args
-                .iter()
-                .flat_map(|expr| {
-                    self.visit_expr(expr);
-                    std::mem::take(&mut self.ret_vars)
-                })
-                .collect_vec()
-                .into_iter()
-                .map(|id| {
-                    self.has_side_effect.insert(id.0);
-                    id
-                })
-                .collect();
-            self.contains_side_effect = true;
-        }
-
-        self.ret_vars.append(&mut ret_vars);
-    }
-
-    fn visit_method_call(&mut self, path: &'tcx PathSegment<'tcx>, args: &'tcx [Expr<'tcx>]) {
-        if_chain! {
-            if self.is_method;
-            if path.ident == self.fn_ident;
-            if let ExprKind::Path(QPath::Resolved(_, path)) = args.first().unwrap().kind;
-            if let Res::Local(..) = path.res;
-            let ident = path.segments.last().unwrap().ident;
-            if ident.name == kw::SelfLower;
-            then {
-                izip!(self.params.clone(), args.iter())
-                    .for_each(|(pat, expr)| {
-                        self.visit_pat_expr(pat, expr, true);
-                        self.ret_vars.clear();
-                    });
-            } else {
-                self.ret_vars = args
-                    .iter()
-                    .flat_map(|expr| {
-                        self.visit_expr(expr);
-                        std::mem::take(&mut self.ret_vars)
-                    })
-                    .collect_vec()
-                    .into_iter()
-                    .map(|a| {
-                        self.has_side_effect.insert(a.0);
-                        a
-                    })
-                    .collect();
-                self.contains_side_effect = true;
-            }
-        }
-    }
-
-    fn visit_if(&mut self, bind: &'tcx Expr<'tcx>, then_expr: &'tcx Expr<'tcx>, else_expr: Option<&'tcx Expr<'tcx>>) {
-        let contains_side_effect = self.contains_side_effect;
-        self.contains_side_effect = false;
-        self.visit_expr(bind);
-        let mut vars = std::mem::take(&mut self.ret_vars);
-        self.visit_expr(then_expr);
-        let mut then_vars = std::mem::take(&mut self.ret_vars);
-        walk_list!(self, visit_expr, else_expr);
-        if self.contains_side_effect {
-            self.add_side_effect(vars.clone());
-        }
-        self.contains_side_effect |= contains_side_effect;
-        self.ret_vars.append(&mut vars);
-        self.ret_vars.append(&mut then_vars);
-    }
-
-    fn visit_match(&mut self, expr: &'tcx Expr<'tcx>, arms: &'tcx [Arm<'tcx>]) {
-        self.visit_expr(expr);
-        let mut expr_vars = std::mem::take(&mut self.ret_vars);
-        self.ret_vars = arms
+            _ => return,
+        };
+        body.params
             .iter()
-            .flat_map(|arm| {
-                let contains_side_effect = self.contains_side_effect;
-                self.contains_side_effect = false;
-                // this would visit `expr` multiple times
-                // but couldn't think of a better way
-                self.visit_pat_expr(arm.pat, expr, false);
-                let mut vars = std::mem::take(&mut self.ret_vars);
-                let _ = arm.guard.as_ref().map(|guard| {
-                    self.visit_expr(match guard {
-                        Guard::If(expr) | Guard::IfLet(Let { init: expr, .. }) => expr,
-                    });
-                    vars.append(&mut self.ret_vars);
-                });
-                self.visit_expr(arm.body);
-                if self.contains_side_effect {
-                    self.add_side_effect(vars.clone());
-                    self.add_side_effect(expr_vars.clone());
-                }
-                self.contains_side_effect |= contains_side_effect;
-                vars.append(&mut self.ret_vars);
-                vars
+            .enumerate()
+            .skip(skip_params)
+            .filter_map(|(idx, p)| match p.pat.kind {
+                PatKind::Binding(_, id, ident, None) if !ident.as_str().starts_with('_') => {
+                    Some((id, Param::new(fn_id, fn_kind, idx, ident)))
+                },
+                _ => None,
             })
-            .collect();
-        self.ret_vars.append(&mut expr_vars);
+            .for_each(|(id, param)| self.params.insert(param, id));
+        if self.entered_body.is_none() {
+            self.entered_body = Some(body.value.hir_id);
+        }
     }
 
-    fn connect_assign(&mut self, lhs: &[(HirId, bool)], rhs: &[(HirId, bool)], connect_self: bool) {
-        // if mutable dereference is on assignment it can have side-effect
-        // (this can lead to parameter mutable dereference and change the original value)
-        // too hard to detect whether this value is from parameter, so this would all
-        // check mutable dereference assignment to side effect
-        lhs.iter().filter(|(_, b)| *b).for_each(|(id, _)| {
-            self.has_side_effect.insert(*id);
-            self.contains_side_effect = true;
-        });
-
-        // there is no connection
-        if lhs.is_empty() || rhs.is_empty() {
-            return;
-        }
-
-        // by connected rhs in cycle, the connections would decrease
-        // from `n * m` to `n + m`
-        // where `n` and `m` are length of `lhs` and `rhs`.
-
-        // unwrap is possible since rhs is not empty
-        let rhs_first = rhs.first().unwrap();
-        for (id, _) in lhs.iter() {
-            if connect_self || *id != rhs_first.0 {
-                self.graph
-                    .entry(*id)
-                    .or_insert_with(FxHashSet::default)
-                    .insert(rhs_first.0);
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) {
+        if let Some(id) = path_to_local(e)
+            && let Some(param) = self.params.get_by_id_mut(id)
+        {
+            let typeck = cx.typeck_results();
+            let span = e.span;
+            let mut e = e;
+            loop {
+                match get_expr_use_or_unification_node(cx.tcx, e) {
+                    None | Some((Node::Stmt(_), _)) => return,
+                    Some((Node::Expr(parent), child_id)) => match parent.kind {
+                        // Recursive call. Track which index the parameter is used in.
+                        ExprKind::Call(callee, args)
+                            if path_def_id(cx, callee).map_or(false, |id| {
+                                id == param.fn_id
+                                    && has_matching_substs(param.fn_kind, typeck.node_substs(callee.hir_id))
+                            }) =>
+                        {
+                            if let Some(idx) = args.iter().position(|arg| arg.hir_id == child_id) {
+                                param.uses.push(Usage::new(span, idx));
+                            }
+                            return;
+                        },
+                        ExprKind::MethodCall(_, receiver, args, _)
+                            if typeck.type_dependent_def_id(parent.hir_id).map_or(false, |id| {
+                                id == param.fn_id
+                                    && has_matching_substs(param.fn_kind, typeck.node_substs(parent.hir_id))
+                            }) =>
+                        {
+                            if let Some(idx) = iter::once(receiver).chain(args).position(|arg| arg.hir_id == child_id) {
+                                param.uses.push(Usage::new(span, idx));
+                            }
+                            return;
+                        },
+                        // Assignment to a parameter is fine.
+                        ExprKind::Assign(lhs, _, _) | ExprKind::AssignOp(_, lhs, _) if lhs.hir_id == child_id => {
+                            return;
+                        },
+                        // Parameter update e.g. `x = x + 1`
+                        ExprKind::Assign(lhs, rhs, _) | ExprKind::AssignOp(_, lhs, rhs)
+                            if rhs.hir_id == child_id && path_to_local_id(lhs, id) =>
+                        {
+                            return;
+                        },
+                        // Side-effect free expressions. Walk to the parent expression.
+                        ExprKind::Binary(_, lhs, rhs)
+                            if typeck.expr_ty(lhs).is_primitive() && typeck.expr_ty(rhs).is_primitive() =>
+                        {
+                            e = parent;
+                            continue;
+                        },
+                        ExprKind::Unary(_, arg) if typeck.expr_ty(arg).is_primitive() => {
+                            e = parent;
+                            continue;
+                        },
+                        ExprKind::AddrOf(..) | ExprKind::Cast(..) => {
+                            e = parent;
+                            continue;
+                        },
+                        // Only allow field accesses without auto-deref
+                        ExprKind::Field(..) if typeck.adjustments().get(child_id).is_none() => {
+                            e = parent;
+                            continue
+                        }
+                        _ => (),
+                    },
+                    _ => (),
+                }
+                self.params.remove_by_id(id);
+                return;
             }
         }
-
-        let rhs = rhs.iter();
-        izip!(rhs.clone().cycle().skip(1), rhs).for_each(|(from, to)| {
-            if connect_self || from.0 != to.0 {
-                self.graph.entry(from.0).or_insert_with(FxHashSet::default).insert(to.0);
-            }
-        });
     }
 
-    fn add_side_effect(&mut self, v: Vec<(HirId, bool)>) {
-        for (id, _) in v {
-            self.has_side_effect.insert(id);
-            self.contains_side_effect = true;
+    fn check_body_post(&mut self, cx: &LateContext<'tcx>, body: &'tcx Body<'tcx>) {
+        if self.entered_body == Some(body.value.hir_id) {
+            self.entered_body = None;
+            self.params.flag_for_linting();
+            for param in &self.params.params {
+                if param.apply_lint.get() {
+                    span_lint_and_then(
+                        cx,
+                        ONLY_USED_IN_RECURSION,
+                        param.ident.span,
+                        "parameter is only used in recursion",
+                        |diag| {
+                            if param.ident.name != kw::SelfLower {
+                                diag.span_suggestion(
+                                    param.ident.span,
+                                    "if this is intentional, prefix it with an underscore",
+                                    format!("_{}", param.ident.name),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            }
+                            diag.span_note(
+                                param.uses.iter().map(|x| x.span).collect::<Vec<_>>(),
+                                "parameter used here",
+                            );
+                        },
+                    );
+                }
+            }
+            self.params.clear();
         }
     }
 }
+
+fn has_matching_substs(kind: FnKind, substs: SubstsRef<'_>) -> bool {
+    match kind {
+        FnKind::Fn => true,
+        FnKind::TraitFn => substs.iter().enumerate().all(|(idx, subst)| match subst.unpack() {
+            GenericArgKind::Lifetime(_) => true,
+            GenericArgKind::Type(ty) => matches!(*ty.kind(), ty::Param(ty) if ty.index as usize == idx),
+            GenericArgKind::Const(c) => matches!(c.kind(), ConstKind::Param(c) if c.index as usize == idx),
+        }),
+        #[allow(trivial_casts)]
+        FnKind::ImplTraitFn(expected_substs) => substs as *const _ as usize == expected_substs,
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/operators/arithmetic.rs b/src/tools/clippy/clippy_lints/src/operators/arithmetic.rs
deleted file mode 100644
index 800cf249f5c7..000000000000
--- a/src/tools/clippy/clippy_lints/src/operators/arithmetic.rs
+++ /dev/null
@@ -1,119 +0,0 @@
-#![allow(
-    // False positive
-    clippy::match_same_arms
-)]
-
-use super::ARITHMETIC;
-use clippy_utils::{consts::constant_simple, diagnostics::span_lint};
-use rustc_data_structures::fx::FxHashSet;
-use rustc_hir as hir;
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::impl_lint_pass;
-use rustc_span::source_map::Span;
-
-const HARD_CODED_ALLOWED: &[&str] = &["std::num::Saturating", "std::string::String", "std::num::Wrapping"];
-
-#[derive(Debug)]
-pub struct Arithmetic {
-    allowed: FxHashSet<String>,
-    // Used to check whether expressions are constants, such as in enum discriminants and consts
-    const_span: Option<Span>,
-    expr_span: Option<Span>,
-}
-
-impl_lint_pass!(Arithmetic => [ARITHMETIC]);
-
-impl Arithmetic {
-    #[must_use]
-    pub fn new(mut allowed: FxHashSet<String>) -> Self {
-        allowed.extend(HARD_CODED_ALLOWED.iter().copied().map(String::from));
-        Self {
-            allowed,
-            const_span: None,
-            expr_span: None,
-        }
-    }
-
-    /// Checks if the given `expr` has any of the inner `allowed` elements.
-    fn is_allowed_ty(&self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
-        self.allowed.contains(
-            cx.typeck_results()
-                .expr_ty(expr)
-                .to_string()
-                .split('<')
-                .next()
-                .unwrap_or_default(),
-        )
-    }
-
-    fn issue_lint(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
-        span_lint(cx, ARITHMETIC, expr.span, "arithmetic detected");
-        self.expr_span = Some(expr.span);
-    }
-}
-
-impl<'tcx> LateLintPass<'tcx> for Arithmetic {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if self.expr_span.is_some() {
-            return;
-        }
-        if let Some(span) = self.const_span && span.contains(expr.span) {
-            return;
-        }
-        match &expr.kind {
-            hir::ExprKind::Binary(op, lhs, rhs) | hir::ExprKind::AssignOp(op, lhs, rhs) => {
-                let (
-                    hir::BinOpKind::Add
-                    | hir::BinOpKind::Sub
-                    | hir::BinOpKind::Mul
-                    | hir::BinOpKind::Div
-                    | hir::BinOpKind::Rem
-                    | hir::BinOpKind::Shl
-                    | hir::BinOpKind::Shr
-                ) = op.node else {
-                    return;
-                };
-                if self.is_allowed_ty(cx, lhs) || self.is_allowed_ty(cx, rhs) {
-                    return;
-                }
-                self.issue_lint(cx, expr);
-            },
-            hir::ExprKind::Unary(hir::UnOp::Neg, _) => {
-                // CTFE already takes care of things like `-1` that do not overflow.
-                if constant_simple(cx, cx.typeck_results(), expr).is_none() {
-                    self.issue_lint(cx, expr);
-                }
-            },
-            _ => {},
-        }
-    }
-
-    fn check_body(&mut self, cx: &LateContext<'_>, body: &hir::Body<'_>) {
-        let body_owner = cx.tcx.hir().body_owner_def_id(body.id());
-        match cx.tcx.hir().body_owner_kind(body_owner) {
-            hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => {
-                let body_span = cx.tcx.def_span(body_owner);
-                if let Some(span) = self.const_span && span.contains(body_span) {
-                    return;
-                }
-                self.const_span = Some(body_span);
-            },
-            hir::BodyOwnerKind::Closure | hir::BodyOwnerKind::Fn => {},
-        }
-    }
-
-    fn check_body_post(&mut self, cx: &LateContext<'_>, body: &hir::Body<'_>) {
-        let body_owner = cx.tcx.hir().body_owner(body.id());
-        let body_span = cx.tcx.hir().span(body_owner);
-        if let Some(span) = self.const_span && span.contains(body_span) {
-            return;
-        }
-        self.const_span = None;
-    }
-
-    fn check_expr_post(&mut self, _: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if Some(expr.span) == self.expr_span {
-            self.expr_span = None;
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/operators/arithmetic_side_effects.rs b/src/tools/clippy/clippy_lints/src/operators/arithmetic_side_effects.rs
new file mode 100644
index 000000000000..d24c57c0a4b8
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/operators/arithmetic_side_effects.rs
@@ -0,0 +1,182 @@
+#![allow(
+    // False positive
+    clippy::match_same_arms
+)]
+
+use super::ARITHMETIC_SIDE_EFFECTS;
+use clippy_utils::{consts::constant_simple, diagnostics::span_lint};
+use rustc_ast as ast;
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir as hir;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::Ty;
+use rustc_session::impl_lint_pass;
+use rustc_span::source_map::{Span, Spanned};
+
+const HARD_CODED_ALLOWED: &[&str] = &[
+    "f32",
+    "f64",
+    "std::num::Saturating",
+    "std::string::String",
+    "std::num::Wrapping",
+];
+
+#[derive(Debug)]
+pub struct ArithmeticSideEffects {
+    allowed: FxHashSet<String>,
+    // Used to check whether expressions are constants, such as in enum discriminants and consts
+    const_span: Option<Span>,
+    expr_span: Option<Span>,
+}
+
+impl_lint_pass!(ArithmeticSideEffects => [ARITHMETIC_SIDE_EFFECTS]);
+
+impl ArithmeticSideEffects {
+    #[must_use]
+    pub fn new(mut allowed: FxHashSet<String>) -> Self {
+        allowed.extend(HARD_CODED_ALLOWED.iter().copied().map(String::from));
+        Self {
+            allowed,
+            const_span: None,
+            expr_span: None,
+        }
+    }
+
+    /// Assuming that `expr` is a literal integer, checks operators (+=, -=, *, /) in a
+    /// non-constant environment that won't overflow.
+    fn has_valid_op(op: &Spanned<hir::BinOpKind>, expr: &hir::Expr<'_>) -> bool {
+        if let hir::BinOpKind::Add | hir::BinOpKind::Sub = op.node
+            && let hir::ExprKind::Lit(ref lit) = expr.kind
+            && let ast::LitKind::Int(0, _) = lit.node
+        {
+            return true;
+        }
+        if let hir::BinOpKind::Div | hir::BinOpKind::Rem = op.node
+            && let hir::ExprKind::Lit(ref lit) = expr.kind
+            && !matches!(lit.node, ast::LitKind::Int(0, _))
+        {
+            return true;
+        }
+        if let hir::BinOpKind::Mul = op.node
+            && let hir::ExprKind::Lit(ref lit) = expr.kind
+            && let ast::LitKind::Int(0 | 1, _) = lit.node
+        {
+            return true;
+        }
+        false
+    }
+
+    /// Checks if the given `expr` has any of the inner `allowed` elements.
+    fn is_allowed_ty(&self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
+        self.allowed.contains(
+            cx.typeck_results()
+                .expr_ty(expr)
+                .to_string()
+                .split('<')
+                .next()
+                .unwrap_or_default(),
+        )
+    }
+
+    /// Explicit integers like `1` or `i32::MAX`. Does not take into consideration references.
+    fn is_literal_integer(expr: &hir::Expr<'_>, expr_refs: Ty<'_>) -> bool {
+        let is_integral = expr_refs.is_integral();
+        let is_literal = matches!(expr.kind, hir::ExprKind::Lit(_));
+        is_integral && is_literal
+    }
+
+    fn issue_lint(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
+        let msg = "arithmetic operation that can potentially result in unexpected side-effects";
+        span_lint(cx, ARITHMETIC_SIDE_EFFECTS, expr.span, msg);
+        self.expr_span = Some(expr.span);
+    }
+
+    /// Manages when the lint should be triggered. Operations in constant environments, hard coded
+    /// types, custom allowed types and non-constant operations that won't overflow are ignored.
+    fn manage_bin_ops(
+        &mut self,
+        cx: &LateContext<'_>,
+        expr: &hir::Expr<'_>,
+        op: &Spanned<hir::BinOpKind>,
+        lhs: &hir::Expr<'_>,
+        rhs: &hir::Expr<'_>,
+    ) {
+        if constant_simple(cx, cx.typeck_results(), expr).is_some() {
+            return;
+        }
+        if !matches!(
+            op.node,
+            hir::BinOpKind::Add
+                | hir::BinOpKind::Sub
+                | hir::BinOpKind::Mul
+                | hir::BinOpKind::Div
+                | hir::BinOpKind::Rem
+                | hir::BinOpKind::Shl
+                | hir::BinOpKind::Shr
+        ) {
+            return;
+        };
+        if self.is_allowed_ty(cx, lhs) || self.is_allowed_ty(cx, rhs) {
+            return;
+        }
+        let has_valid_op = match (
+            Self::is_literal_integer(lhs, cx.typeck_results().expr_ty(lhs).peel_refs()),
+            Self::is_literal_integer(rhs, cx.typeck_results().expr_ty(rhs).peel_refs()),
+        ) {
+            (true, true) => true,
+            (true, false) => Self::has_valid_op(op, lhs),
+            (false, true) => Self::has_valid_op(op, rhs),
+            (false, false) => false,
+        };
+        if !has_valid_op {
+            self.issue_lint(cx, expr);
+        }
+    }
+}
+
+impl<'tcx> LateLintPass<'tcx> for ArithmeticSideEffects {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
+        if self.expr_span.is_some() || self.const_span.map_or(false, |sp| sp.contains(expr.span)) {
+            return;
+        }
+        match &expr.kind {
+            hir::ExprKind::Binary(op, lhs, rhs) | hir::ExprKind::AssignOp(op, lhs, rhs) => {
+                self.manage_bin_ops(cx, expr, op, lhs, rhs);
+            },
+            hir::ExprKind::Unary(hir::UnOp::Neg, _) => {
+                if constant_simple(cx, cx.typeck_results(), expr).is_none() {
+                    self.issue_lint(cx, expr);
+                }
+            },
+            _ => {},
+        }
+    }
+
+    fn check_body(&mut self, cx: &LateContext<'_>, body: &hir::Body<'_>) {
+        let body_owner = cx.tcx.hir().body_owner(body.id());
+        let body_owner_def_id = cx.tcx.hir().local_def_id(body_owner);
+        let body_owner_kind = cx.tcx.hir().body_owner_kind(body_owner_def_id);
+        if let hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) = body_owner_kind {
+            let body_span = cx.tcx.hir().span_with_body(body_owner);
+            if let Some(span) = self.const_span && span.contains(body_span) {
+                return;
+            }
+            self.const_span = Some(body_span);
+        }
+    }
+
+    fn check_body_post(&mut self, cx: &LateContext<'_>, body: &hir::Body<'_>) {
+        let body_owner = cx.tcx.hir().body_owner(body.id());
+        let body_span = cx.tcx.hir().span(body_owner);
+        if let Some(span) = self.const_span && span.contains(body_span) {
+            return;
+        }
+        self.const_span = None;
+    }
+
+    fn check_expr_post(&mut self, _: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
+        if Some(expr.span) == self.expr_span {
+            self.expr_span = None;
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs b/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs
index 945a09a647c4..2c22c8b3d081 100644
--- a/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs
@@ -28,7 +28,7 @@ pub(super) fn check<'tcx>(
             if_chain! {
                 if let Some((_, lang_item)) = binop_traits(op.node);
                 if let Ok(trait_id) = cx.tcx.lang_items().require(lang_item);
-                let parent_fn = cx.tcx.hir().get_parent_item(e.hir_id);
+                let parent_fn = cx.tcx.hir().get_parent_item(e.hir_id).def_id;
                 if trait_ref_of_method(cx, parent_fn)
                     .map_or(true, |t| t.path.res.def_id() != trait_id);
                 if implements_trait(cx, ty, trait_id, &[rty.into()]);
diff --git a/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs b/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs
index e1f9b5906f66..638a514ff9b3 100644
--- a/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/cmp_owned.rs
@@ -38,7 +38,7 @@ fn symmetric_partial_eq<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, other: Ty<'t
 fn check_op(cx: &LateContext<'_>, expr: &Expr<'_>, other: &Expr<'_>, left: bool) {
     let typeck = cx.typeck_results();
     let (arg, arg_span) = match expr.kind {
-        ExprKind::MethodCall(.., [arg], _)
+        ExprKind::MethodCall(_, arg, [], _)
             if typeck
                 .type_dependent_def_id(expr.hir_id)
                 .and_then(|id| cx.tcx.trait_of_item(id))
diff --git a/src/tools/clippy/clippy_lints/src/operators/duration_subsec.rs b/src/tools/clippy/clippy_lints/src/operators/duration_subsec.rs
index 0d067d1e1968..827a2b267093 100644
--- a/src/tools/clippy/clippy_lints/src/operators/duration_subsec.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/duration_subsec.rs
@@ -17,7 +17,7 @@ pub(crate) fn check<'tcx>(
     right: &'tcx Expr<'_>,
 ) {
     if op == BinOpKind::Div
-        && let ExprKind::MethodCall(method_path, [self_arg], _) = left.kind
+        && let ExprKind::MethodCall(method_path, self_arg, [], _) = left.kind
         && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(self_arg).peel_refs(), sym::Duration)
         && let Some((Constant::Int(divisor), _)) = constant(cx, cx.typeck_results(), right)
     {
diff --git a/src/tools/clippy/clippy_lints/src/operators/float_cmp.rs b/src/tools/clippy/clippy_lints/src/operators/float_cmp.rs
index 0ef793443ff4..97ddcdb24799 100644
--- a/src/tools/clippy/clippy_lints/src/operators/float_cmp.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/float_cmp.rs
@@ -113,7 +113,7 @@ fn is_signum(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     }
 
     if_chain! {
-        if let ExprKind::MethodCall(method_name, [ref self_arg, ..], _) = expr.kind;
+        if let ExprKind::MethodCall(method_name, self_arg, ..) = expr.kind;
         if sym!(signum) == method_name.ident.name;
         // Check that the receiver of the signum() is a float (expressions[0] is the receiver of
         // the method call)
diff --git a/src/tools/clippy/clippy_lints/src/operators/mod.rs b/src/tools/clippy/clippy_lints/src/operators/mod.rs
index bb6d99406b49..c32b4df4f75c 100644
--- a/src/tools/clippy/clippy_lints/src/operators/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/mod.rs
@@ -21,7 +21,7 @@ mod ptr_eq;
 mod self_assignment;
 mod verbose_bit_mask;
 
-pub(crate) mod arithmetic;
+pub(crate) mod arithmetic_side_effects;
 
 use rustc_hir::{Body, Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
@@ -61,25 +61,29 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for any kind of arithmetic operation of any type.
+    /// Checks any kind of arithmetic operation of any type.
     ///
     /// Operators like `+`, `-`, `*` or `<<` are usually capable of overflowing according to the [Rust
     /// Reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#overflow),
-    /// or can panic (`/`, `%`). Known safe built-in types like `Wrapping` or `Saturing` are filtered
-    /// away.
+    /// or can panic (`/`, `%`).
+    ///
+    /// Known safe built-in types like `Wrapping` or `Saturing`, floats, operations in constant
+    /// environments, allowed types and non-constant operations that won't overflow are ignored.
     ///
     /// ### Why is this bad?
-    /// Integer overflow will trigger a panic in debug builds or will wrap in
-    /// release mode. Division by zero will cause a panic in either mode. In some applications one
-    /// wants explicitly checked, wrapping or saturating arithmetic.
+    /// For integers, overflow will trigger a panic in debug builds or wrap the result in
+    /// release mode; division by zero will cause a panic in either mode. As a result, it is
+    /// desirable to explicitly call checked, wrapping or saturating arithmetic methods.
     ///
     /// #### Example
     /// ```rust
-    /// # let a = 0;
-    /// a + 1;
+    /// // `n` can be any number, including `i32::MAX`.
+    /// fn foo(n: i32) -> i32 {
+    ///   n + 1
+    /// }
     /// ```
     ///
-    /// Third-party types also tend to overflow.
+    /// Third-party types can also overflow or present unwanted side-effects.
     ///
     /// #### Example
     /// ```ignore,rust
@@ -88,11 +92,11 @@ declare_clippy_lint! {
     /// ```
     ///
     /// ### Allowed types
-    /// Custom allowed types can be specified through the "arithmetic-allowed" filter.
+    /// Custom allowed types can be specified through the "arithmetic-side-effects-allowed" filter.
     #[clippy::version = "1.64.0"]
-    pub ARITHMETIC,
+    pub ARITHMETIC_SIDE_EFFECTS,
     restriction,
-    "any arithmetic expression that could overflow or panic"
+    "any arithmetic expression that can cause side effects like overflows or panics"
 }
 
 declare_clippy_lint! {
@@ -785,7 +789,7 @@ pub struct Operators {
 }
 impl_lint_pass!(Operators => [
     ABSURD_EXTREME_COMPARISONS,
-    ARITHMETIC,
+    ARITHMETIC_SIDE_EFFECTS,
     INTEGER_ARITHMETIC,
     FLOAT_ARITHMETIC,
     ASSIGN_OP_PATTERN,
diff --git a/src/tools/clippy/clippy_lints/src/operators/op_ref.rs b/src/tools/clippy/clippy_lints/src/operators/op_ref.rs
index 1805672e3725..1085e6089441 100644
--- a/src/tools/clippy/clippy_lints/src/operators/op_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/op_ref.rs
@@ -185,7 +185,7 @@ fn in_impl<'tcx>(
         if let ItemKind::Impl(item) = &item.kind;
         if let Some(of_trait) = &item.of_trait;
         if let Some(seg) = of_trait.path.segments.last();
-        if let Some(Res::Def(_, trait_id)) = seg.res;
+        if let Res::Def(_, trait_id) = seg.res;
         if trait_id == bin_op;
         if let Some(generic_args) = seg.args;
         if let Some(GenericArg::Type(other_ty)) = generic_args.args.last();
diff --git a/src/tools/clippy/clippy_lints/src/option_if_let_else.rs b/src/tools/clippy/clippy_lints/src/option_if_let_else.rs
index 44f153cffac5..0315678bf97a 100644
--- a/src/tools/clippy/clippy_lints/src/option_if_let_else.rs
+++ b/src/tools/clippy/clippy_lints/src/option_if_let_else.rs
@@ -1,21 +1,22 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::sugg::Sugg;
-use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::{
     can_move_expr_to_closure, eager_or_lazy, higher, in_constant, is_else_clause, is_lang_ctor, peel_blocks,
     peel_hir_expr_while, CaptureKind,
 };
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::LangItem::OptionSome;
-use rustc_hir::{def::Res, BindingAnnotation, Expr, ExprKind, Mutability, PatKind, Path, QPath, UnOp};
+use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk};
+use rustc_hir::{
+    def::Res, Arm, BindingAnnotation, Expr, ExprKind, MatchSource, Mutability, Pat, PatKind, Path, QPath, UnOp,
+};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Lints usage of `if let Some(v) = ... { y } else { x }` which is more
+    /// Lints usage of `if let Some(v) = ... { y } else { x }` and
+    /// `match .. { Some(v) => y, None/_ => x }` which are more
     /// idiomatically done with `Option::map_or` (if the else bit is a pure
     /// expression) or `Option::map_or_else` (if the else bit is an impure
     /// expression).
@@ -39,6 +40,10 @@ declare_clippy_lint! {
     /// } else {
     ///     5
     /// };
+    /// let _ = match optional {
+    ///     Some(val) => val + 1,
+    ///     None => 5
+    /// };
     /// let _ = if let Some(foo) = optional {
     ///     foo
     /// } else {
@@ -53,11 +58,14 @@ declare_clippy_lint! {
     /// # let optional: Option<u32> = Some(0);
     /// # fn do_complicated_function() -> u32 { 5 };
     /// let _ = optional.map_or(5, |foo| foo);
+    /// let _ = optional.map_or(5, |val| val + 1);
     /// let _ = optional.map_or_else(||{
     ///     let y = do_complicated_function();
     ///     y*y
     /// }, |foo| foo);
     /// ```
+    // FIXME: Before moving this lint out of nursery, the lint name needs to be updated. It now also
+    // covers matches and `Result`.
     #[clippy::version = "1.47.0"]
     pub OPTION_IF_LET_ELSE,
     nursery,
@@ -66,19 +74,21 @@ declare_clippy_lint! {
 
 declare_lint_pass!(OptionIfLetElse => [OPTION_IF_LET_ELSE]);
 
-/// Returns true iff the given expression is the result of calling `Result::ok`
-fn is_result_ok(cx: &LateContext<'_>, expr: &'_ Expr<'_>) -> bool {
-    if let ExprKind::MethodCall(path, &[ref receiver], _) = &expr.kind {
-        path.ident.name.as_str() == "ok"
-            && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(receiver), sym::Result)
-    } else {
-        false
-    }
-}
-
-/// A struct containing information about occurrences of the
-/// `if let Some(..) = .. else` construct that this lint detects.
-struct OptionIfLetElseOccurrence {
+/// A struct containing information about occurrences of construct that this lint detects
+///
+/// Such as:
+///
+/// ```ignore
+/// if let Some(..) = {..} else {..}
+/// ```
+/// or
+/// ```ignore
+/// match x {
+///     Some(..) => {..},
+///     None/_ => {..}
+/// }
+/// ```
+struct OptionOccurence {
     option: String,
     method_sugg: String,
     some_expr: String,
@@ -99,43 +109,38 @@ fn format_option_in_sugg(cx: &LateContext<'_>, cond_expr: &Expr<'_>, as_ref: boo
     )
 }
 
-/// If this expression is the option if let/else construct we're detecting, then
-/// this function returns an `OptionIfLetElseOccurrence` struct with details if
-/// this construct is found, or None if this construct is not found.
-fn detect_option_if_let_else<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<OptionIfLetElseOccurrence> {
+fn try_get_option_occurence<'tcx>(
+    cx: &LateContext<'tcx>,
+    pat: &Pat<'tcx>,
+    expr: &Expr<'_>,
+    if_then: &'tcx Expr<'_>,
+    if_else: &'tcx Expr<'_>,
+) -> Option<OptionOccurence> {
+    let cond_expr = match expr.kind {
+        ExprKind::Unary(UnOp::Deref, inner_expr) | ExprKind::AddrOf(_, _, inner_expr) => inner_expr,
+        _ => expr,
+    };
+    let inner_pat = try_get_inner_pat(cx, pat)?;
     if_chain! {
-        if !expr.span.from_expansion(); // Don't lint macros, because it behaves weirdly
-        if !in_constant(cx, expr.hir_id);
-        if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: Some(if_else) })
-            = higher::IfLet::hir(cx, expr);
-        if !is_else_clause(cx.tcx, expr);
-        if !is_result_ok(cx, let_expr); // Don't lint on Result::ok because a different lint does it already
-        if let PatKind::TupleStruct(struct_qpath, [inner_pat], _) = &let_pat.kind;
-        if is_lang_ctor(cx, struct_qpath, OptionSome);
-        if let PatKind::Binding(bind_annotation, _, id, None) = &inner_pat.kind;
+        if let PatKind::Binding(bind_annotation, _, id, None) = inner_pat.kind;
         if let Some(some_captures) = can_move_expr_to_closure(cx, if_then);
         if let Some(none_captures) = can_move_expr_to_closure(cx, if_else);
         if some_captures
             .iter()
             .filter_map(|(id, &c)| none_captures.get(id).map(|&c2| (c, c2)))
             .all(|(x, y)| x.is_imm_ref() && y.is_imm_ref());
-
         then {
-            let capture_mut = if bind_annotation == &BindingAnnotation::Mutable { "mut " } else { "" };
+            let capture_mut = if bind_annotation == BindingAnnotation::MUT { "mut " } else { "" };
             let some_body = peel_blocks(if_then);
             let none_body = peel_blocks(if_else);
             let method_sugg = if eager_or_lazy::switch_to_eager_eval(cx, none_body) { "map_or" } else { "map_or_else" };
             let capture_name = id.name.to_ident_string();
-            let (as_ref, as_mut) = match &let_expr.kind {
+            let (as_ref, as_mut) = match &expr.kind {
                 ExprKind::AddrOf(_, Mutability::Not, _) => (true, false),
                 ExprKind::AddrOf(_, Mutability::Mut, _) => (false, true),
-                _ => (bind_annotation == &BindingAnnotation::Ref, bind_annotation == &BindingAnnotation::RefMut),
-            };
-            let cond_expr = match let_expr.kind {
-                // Pointer dereferencing happens automatically, so we can omit it in the suggestion
-                ExprKind::Unary(UnOp::Deref, expr) | ExprKind::AddrOf(_, _, expr) => expr,
-                _ => let_expr,
+                _ => (bind_annotation == BindingAnnotation::REF, bind_annotation == BindingAnnotation::REF_MUT),
             };
+
             // Check if captures the closure will need conflict with borrows made in the scrutinee.
             // TODO: check all the references made in the scrutinee expression. This will require interacting
             // with the borrow checker. Currently only `<local>[.<field>]*` is checked for.
@@ -154,30 +159,100 @@ fn detect_option_if_let_else<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) ->
                     }
                 }
             }
-            Some(OptionIfLetElseOccurrence {
+
+            return Some(OptionOccurence {
                 option: format_option_in_sugg(cx, cond_expr, as_ref, as_mut),
                 method_sugg: method_sugg.to_string(),
                 some_expr: format!("|{}{}| {}", capture_mut, capture_name, Sugg::hir_with_macro_callsite(cx, some_body, "..")),
                 none_expr: format!("{}{}", if method_sugg == "map_or" { "" } else { "|| " }, Sugg::hir_with_macro_callsite(cx, none_body, "..")),
-            })
+            });
+        }
+    }
+
+    None
+}
+
+fn try_get_inner_pat<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'tcx>) -> Option<&'tcx Pat<'tcx>> {
+    if let PatKind::TupleStruct(ref qpath, [inner_pat], ..) = pat.kind {
+        if is_lang_ctor(cx, qpath, OptionSome) || is_lang_ctor(cx, qpath, ResultOk) {
+            return Some(inner_pat);
+        }
+    }
+    None
+}
+
+/// If this expression is the option if let/else construct we're detecting, then
+/// this function returns an `OptionOccurence` struct with details if
+/// this construct is found, or None if this construct is not found.
+fn detect_option_if_let_else<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<OptionOccurence> {
+    if let Some(higher::IfLet {
+        let_pat,
+        let_expr,
+        if_then,
+        if_else: Some(if_else),
+    }) = higher::IfLet::hir(cx, expr)
+    {
+        if !is_else_clause(cx.tcx, expr) {
+            return try_get_option_occurence(cx, let_pat, let_expr, if_then, if_else);
+        }
+    }
+    None
+}
+
+fn detect_option_match<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<OptionOccurence> {
+    if let ExprKind::Match(ex, arms, MatchSource::Normal) = expr.kind {
+        if let Some((let_pat, if_then, if_else)) = try_convert_match(cx, arms) {
+            return try_get_option_occurence(cx, let_pat, ex, if_then, if_else);
+        }
+    }
+    None
+}
+
+fn try_convert_match<'tcx>(
+    cx: &LateContext<'tcx>,
+    arms: &[Arm<'tcx>],
+) -> Option<(&'tcx Pat<'tcx>, &'tcx Expr<'tcx>, &'tcx Expr<'tcx>)> {
+    if arms.len() == 2 {
+        return if is_none_or_err_arm(cx, &arms[1]) {
+            Some((arms[0].pat, arms[0].body, arms[1].body))
+        } else if is_none_or_err_arm(cx, &arms[0]) {
+            Some((arms[1].pat, arms[1].body, arms[0].body))
         } else {
             None
-        }
+        };
+    }
+    None
+}
+
+fn is_none_or_err_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
+    match arm.pat.kind {
+        PatKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
+        PatKind::TupleStruct(ref qpath, [first_pat], _) => {
+            is_lang_ctor(cx, qpath, ResultErr) && matches!(first_pat.kind, PatKind::Wild)
+        },
+        PatKind::Wild => true,
+        _ => false,
     }
 }
 
 impl<'tcx> LateLintPass<'tcx> for OptionIfLetElse {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) {
-        if let Some(detection) = detect_option_if_let_else(cx, expr) {
+        // Don't lint macros and constants
+        if expr.span.from_expansion() || in_constant(cx, expr.hir_id) {
+            return;
+        }
+
+        let detection = detect_option_if_let_else(cx, expr).or_else(|| detect_option_match(cx, expr));
+        if let Some(det) = detection {
             span_lint_and_sugg(
                 cx,
                 OPTION_IF_LET_ELSE,
                 expr.span,
-                format!("use Option::{} instead of an if let/else", detection.method_sugg).as_str(),
+                format!("use Option::{} instead of an if let/else", det.method_sugg).as_str(),
                 "try",
                 format!(
                     "{}.{}({}, {})",
-                    detection.option, detection.method_sugg, detection.none_expr, detection.some_expr,
+                    det.option, det.method_sugg, det.none_expr, det.some_expr
                 ),
                 Applicability::MaybeIncorrect,
             );
diff --git a/src/tools/clippy/clippy_lints/src/panic_in_result_fn.rs b/src/tools/clippy/clippy_lints/src/panic_in_result_fn.rs
index 21acf003d92b..4aa0d9227aba 100644
--- a/src/tools/clippy/clippy_lints/src/panic_in_result_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/panic_in_result_fn.rs
@@ -69,7 +69,7 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir
         }
         true
     })
-    .visit_expr(&body.value);
+    .visit_expr(body.value);
     if !panics.is_empty() {
         span_lint_and_then(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/partialeq_to_none.rs b/src/tools/clippy/clippy_lints/src/partialeq_to_none.rs
index eee7642068d6..000b0ba7a148 100644
--- a/src/tools/clippy/clippy_lints/src/partialeq_to_none.rs
+++ b/src/tools/clippy/clippy_lints/src/partialeq_to_none.rs
@@ -53,7 +53,8 @@ impl<'tcx> LateLintPass<'tcx> for PartialeqToNone {
 
         // If the expression is a literal `Option::None`
         let is_none_ctor = |expr: &Expr<'_>| {
-            matches!(&peel_hir_expr_refs(expr).0.kind,
+            !expr.span.from_expansion()
+                && matches!(&peel_hir_expr_refs(expr).0.kind,
             ExprKind::Path(p) if is_lang_ctor(cx, p, LangItem::OptionNone))
         };
 
diff --git a/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs b/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs
index 5fa4fd74853f..6b2eea489322 100644
--- a/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs
+++ b/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs
@@ -221,7 +221,7 @@ impl<'tcx> PassByRefOrValue {
                     // if function has a body and parameter is annotated with mut, ignore
                     if let Some(param) = fn_body.and_then(|body| body.params.get(index)) {
                         match param.pat.kind {
-                            PatKind::Binding(BindingAnnotation::Unannotated, _, _, _) => {},
+                            PatKind::Binding(BindingAnnotation::NONE, _, _, _) => {},
                             _ => continue,
                         }
                     }
@@ -261,7 +261,7 @@ impl<'tcx> LateLintPass<'tcx> for PassByRefOrValue {
         }
 
         if let hir::TraitItemKind::Fn(method_sig, _) = &item.kind {
-            self.check_poly_fn(cx, item.def_id, method_sig.decl, None);
+            self.check_poly_fn(cx, item.def_id.def_id, method_sig.decl, None);
         }
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs b/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs
deleted file mode 100644
index bc6a918f7035..000000000000
--- a/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs
+++ /dev/null
@@ -1,72 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::ty::is_type_diagnostic_item;
-use if_chain::if_chain;
-use rustc_ast::ast::LitKind;
-use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::symbol::sym;
-use std::path::{Component, Path};
-
-declare_clippy_lint! {
-    /// ### What it does
-    ///* Checks for [push](https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.push)
-    /// calls on `PathBuf` that can cause overwrites.
-    ///
-    /// ### Why is this bad?
-    /// Calling `push` with a root path at the start can overwrite the
-    /// previous defined path.
-    ///
-    /// ### Example
-    /// ```rust
-    /// use std::path::PathBuf;
-    ///
-    /// let mut x = PathBuf::from("/foo");
-    /// x.push("/bar");
-    /// assert_eq!(x, PathBuf::from("/bar"));
-    /// ```
-    /// Could be written:
-    ///
-    /// ```rust
-    /// use std::path::PathBuf;
-    ///
-    /// let mut x = PathBuf::from("/foo");
-    /// x.push("bar");
-    /// assert_eq!(x, PathBuf::from("/foo/bar"));
-    /// ```
-    #[clippy::version = "1.36.0"]
-    pub PATH_BUF_PUSH_OVERWRITE,
-    nursery,
-    "calling `push` with file system root on `PathBuf` can overwrite it"
-}
-
-declare_lint_pass!(PathBufPushOverwrite => [PATH_BUF_PUSH_OVERWRITE]);
-
-impl<'tcx> LateLintPass<'tcx> for PathBufPushOverwrite {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if_chain! {
-            if let ExprKind::MethodCall(path, [recv, get_index_arg], _) = expr.kind;
-            if path.ident.name == sym!(push);
-            if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv).peel_refs(), sym::PathBuf);
-            if let ExprKind::Lit(ref lit) = get_index_arg.kind;
-            if let LitKind::Str(ref path_lit, _) = lit.node;
-            if let pushed_path = Path::new(path_lit.as_str());
-            if let Some(pushed_path_lit) = pushed_path.to_str();
-            if pushed_path.has_root();
-            if let Some(root) = pushed_path.components().next();
-            if root == Component::RootDir;
-            then {
-                span_lint_and_sugg(
-                    cx,
-                    PATH_BUF_PUSH_OVERWRITE,
-                    lit.span,
-                    "calling `push` with '/' or '\\' (file system root) will overwrite the previous path definition",
-                    "try",
-                    format!("\"{}\"", pushed_path_lit.trim_start_matches(|c| c == '/' || c == '\\')),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/ptr.rs b/src/tools/clippy/clippy_lints/src/ptr.rs
index 3c5ea2d94144..41d1baba64f8 100644
--- a/src/tools/clippy/clippy_lints/src/ptr.rs
+++ b/src/tools/clippy/clippy_lints/src/ptr.rs
@@ -507,7 +507,7 @@ fn check_mut_from_ref<'tcx>(cx: &LateContext<'tcx>, sig: &FnSig<'_>, body: Optio
         if let Some(args) = args
             && !args.is_empty()
             && body.map_or(true, |body| {
-                sig.header.unsafety == Unsafety::Unsafe || contains_unsafe_block(cx, &body.value)
+                sig.header.unsafety == Unsafety::Unsafe || contains_unsafe_block(cx, body.value)
             })
         {
             span_lint_and_then(
@@ -571,7 +571,7 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
                 Some((Node::Stmt(_), _)) => (),
                 Some((Node::Local(l), _)) => {
                     // Only trace simple bindings. e.g `let x = y;`
-                    if let PatKind::Binding(BindingAnnotation::Unannotated, id, _, None) = l.pat.kind {
+                    if let PatKind::Binding(BindingAnnotation::NONE, id, _, None) = l.pat.kind {
                         self.bindings.insert(id, args_idx);
                     } else {
                         set_skip_flag();
@@ -591,8 +591,11 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
                             set_skip_flag();
                         }
                     },
-                    ExprKind::MethodCall(name, expr_args @ [self_arg, ..], _) => {
-                        let i = expr_args.iter().position(|arg| arg.hir_id == child_id).unwrap_or(0);
+                    ExprKind::MethodCall(name, self_arg, expr_args, _) => {
+                        let i = std::iter::once(self_arg)
+                            .chain(expr_args.iter())
+                            .position(|arg| arg.hir_id == child_id)
+                            .unwrap_or(0);
                         if i == 0 {
                             // Check if the method can be renamed.
                             let name = name.ident.as_str();
@@ -644,7 +647,7 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
             .filter_map(|(i, arg)| {
                 let param = &body.params[arg.idx];
                 match param.pat.kind {
-                    PatKind::Binding(BindingAnnotation::Unannotated, id, _, None)
+                    PatKind::Binding(BindingAnnotation::NONE, id, _, None)
                         if !is_lint_allowed(cx, PTR_ARG, param.hir_id) =>
                     {
                         Some((id, i))
@@ -661,7 +664,7 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
         results,
         skip_count,
     };
-    v.visit_expr(&body.value);
+    v.visit_expr(body.value);
     v.results
 }
 
diff --git a/src/tools/clippy/clippy_lints/src/ptr_offset_with_cast.rs b/src/tools/clippy/clippy_lints/src/ptr_offset_with_cast.rs
index b907f38afbb9..4dc65da3ea1f 100644
--- a/src/tools/clippy/clippy_lints/src/ptr_offset_with_cast.rs
+++ b/src/tools/clippy/clippy_lints/src/ptr_offset_with_cast.rs
@@ -93,7 +93,7 @@ fn expr_as_ptr_offset_call<'tcx>(
     cx: &LateContext<'tcx>,
     expr: &'tcx Expr<'_>,
 ) -> Option<(&'tcx Expr<'tcx>, &'tcx Expr<'tcx>, Method)> {
-    if let ExprKind::MethodCall(path_segment, [arg_0, arg_1, ..], _) = &expr.kind {
+    if let ExprKind::MethodCall(path_segment, arg_0, [arg_1, ..], _) = &expr.kind {
         if is_expr_ty_raw_ptr(cx, arg_0) {
             if path_segment.ident.name == sym::offset {
                 return Some((arg_0, arg_1, Method::Offset));
diff --git a/src/tools/clippy/clippy_lints/src/question_mark.rs b/src/tools/clippy/clippy_lints/src/question_mark.rs
index 964a057f00d3..569870ab2b7f 100644
--- a/src/tools/clippy/clippy_lints/src/question_mark.rs
+++ b/src/tools/clippy/clippy_lints/src/question_mark.rs
@@ -9,7 +9,7 @@ use clippy_utils::{
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk};
-use rustc_hir::{BindingAnnotation, Expr, ExprKind, Node, PatKind, PathSegment, QPath};
+use rustc_hir::{BindingAnnotation, ByRef, Expr, ExprKind, Node, PatKind, PathSegment, QPath};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::Ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -86,7 +86,7 @@ fn check_is_none_or_err_and_early_return<'tcx>(cx: &LateContext<'tcx>, expr: &Ex
     if_chain! {
         if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr);
         if !is_else_clause(cx.tcx, expr);
-        if let ExprKind::MethodCall(segment, [caller, ..], _) = &cond.kind;
+        if let ExprKind::MethodCall(segment, caller, ..) = &cond.kind;
         let caller_ty = cx.typeck_results().expr_ty(caller);
         let if_block = IfBlockType::IfIs(caller, caller_ty, segment.ident.name, then, r#else);
         if is_early_return(sym::Option, cx, &if_block) || is_early_return(sym::Result, cx, &if_block);
@@ -122,8 +122,9 @@ fn check_if_let_some_or_err_and_early_return<'tcx>(cx: &LateContext<'tcx>, expr:
     if_chain! {
         if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else }) = higher::IfLet::hir(cx, expr);
         if !is_else_clause(cx.tcx, expr);
-        if let PatKind::TupleStruct(ref path1, [field], None) = let_pat.kind;
-        if let PatKind::Binding(annot, bind_id, ident, _) = field.kind;
+        if let PatKind::TupleStruct(ref path1, [field], ddpos) = let_pat.kind;
+        if ddpos.as_opt_usize().is_none();
+        if let PatKind::Binding(BindingAnnotation(by_ref, _), bind_id, ident, None) = field.kind;
         let caller_ty = cx.typeck_results().expr_ty(let_expr);
         let if_block = IfBlockType::IfLet(path1, caller_ty, ident.name, let_expr, if_then, if_else);
         if (is_early_return(sym::Option, cx, &if_block) && path_to_local_id(peel_blocks(if_then), bind_id))
@@ -132,12 +133,11 @@ fn check_if_let_some_or_err_and_early_return<'tcx>(cx: &LateContext<'tcx>, expr:
         then {
             let mut applicability = Applicability::MachineApplicable;
             let receiver_str = snippet_with_applicability(cx, let_expr.span, "..", &mut applicability);
-            let by_ref = matches!(annot, BindingAnnotation::Ref | BindingAnnotation::RefMut);
             let requires_semi = matches!(get_parent_node(cx.tcx, expr.hir_id), Some(Node::Stmt(_)));
             let sugg = format!(
                 "{}{}?{}",
                 receiver_str,
-                if by_ref { ".as_ref()" } else { "" },
+                if by_ref == ByRef::Yes { ".as_ref()" } else { "" },
                 if requires_semi { ";" } else { "" }
             );
             span_lint_and_sugg(
diff --git a/src/tools/clippy/clippy_lints/src/ranges.rs b/src/tools/clippy/clippy_lints/src/ranges.rs
index fbf842c339e4..918d624eec6f 100644
--- a/src/tools/clippy/clippy_lints/src/ranges.rs
+++ b/src/tools/clippy/clippy_lints/src/ranges.rs
@@ -1,46 +1,20 @@
 use clippy_utils::consts::{constant, Constant};
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::higher;
 use clippy_utils::source::{snippet, snippet_opt, snippet_with_applicability};
 use clippy_utils::sugg::Sugg;
 use clippy_utils::{get_parent_expr, in_constant, is_integer_const, meets_msrv, msrvs, path_to_local};
-use clippy_utils::{higher, SpanlessEq};
 use if_chain::if_chain;
 use rustc_ast::ast::RangeLimits;
 use rustc_errors::Applicability;
-use rustc_hir::{BinOpKind, Expr, ExprKind, HirId, PathSegment, QPath};
+use rustc_hir::{BinOpKind, Expr, ExprKind, HirId};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::{Span, Spanned};
-use rustc_span::sym;
 use std::cmp::Ordering;
 
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for zipping a collection with the range of
-    /// `0.._.len()`.
-    ///
-    /// ### Why is this bad?
-    /// The code is better expressed with `.enumerate()`.
-    ///
-    /// ### Example
-    /// ```rust
-    /// # let x = vec![1];
-    /// let _ = x.iter().zip(0..x.len());
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust
-    /// # let x = vec![1];
-    /// let _ = x.iter().enumerate();
-    /// ```
-    #[clippy::version = "pre 1.29.0"]
-    pub RANGE_ZIP_WITH_LEN,
-    complexity,
-    "zipping iterator with a range when `enumerate()` would do"
-}
-
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for exclusive ranges where 1 is added to the
@@ -198,7 +172,6 @@ impl Ranges {
 }
 
 impl_lint_pass!(Ranges => [
-    RANGE_ZIP_WITH_LEN,
     RANGE_PLUS_ONE,
     RANGE_MINUS_ONE,
     REVERSED_EMPTY_RANGES,
@@ -207,16 +180,10 @@ impl_lint_pass!(Ranges => [
 
 impl<'tcx> LateLintPass<'tcx> for Ranges {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        match expr.kind {
-            ExprKind::MethodCall(path, args, _) => {
-                check_range_zip_with_len(cx, path, args, expr.span);
-            },
-            ExprKind::Binary(ref op, l, r) => {
-                if meets_msrv(self.msrv, msrvs::RANGE_CONTAINS) {
-                    check_possible_range_contains(cx, op.node, l, r, expr, expr.span);
-                }
-            },
-            _ => {},
+        if let ExprKind::Binary(ref op, l, r) = expr.kind {
+            if meets_msrv(self.msrv, msrvs::RANGE_CONTAINS) {
+                check_possible_range_contains(cx, op.node, l, r, expr, expr.span);
+            }
         }
 
         check_exclusive_range_plus_one(cx, expr);
@@ -380,37 +347,10 @@ fn check_range_bounds<'a>(cx: &'a LateContext<'_>, ex: &'a Expr<'_>) -> Option<R
     None
 }
 
-fn check_range_zip_with_len(cx: &LateContext<'_>, path: &PathSegment<'_>, args: &[Expr<'_>], span: Span) {
-    if_chain! {
-        if path.ident.as_str() == "zip";
-        if let [iter, zip_arg] = args;
-        // `.iter()` call
-        if let ExprKind::MethodCall(iter_path, [iter_caller, ..], _) = iter.kind;
-        if iter_path.ident.name == sym::iter;
-        // range expression in `.zip()` call: `0..x.len()`
-        if let Some(higher::Range { start: Some(start), end: Some(end), .. }) = higher::Range::hir(zip_arg);
-        if is_integer_const(cx, start, 0);
-        // `.len()` call
-        if let ExprKind::MethodCall(len_path, [len_caller], _) = end.kind;
-        if len_path.ident.name == sym::len;
-        // `.iter()` and `.len()` called on same `Path`
-        if let ExprKind::Path(QPath::Resolved(_, iter_path)) = iter_caller.kind;
-        if let ExprKind::Path(QPath::Resolved(_, len_path)) = len_caller.kind;
-        if SpanlessEq::new(cx).eq_path_segments(iter_path.segments, len_path.segments);
-        then {
-            span_lint(cx,
-                RANGE_ZIP_WITH_LEN,
-                span,
-                &format!("it is more idiomatic to use `{}.iter().enumerate()`",
-                    snippet(cx, iter_caller.span, "_"))
-            );
-        }
-    }
-}
-
 // exclusive range plus one: `x..(y+1)`
 fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
+        if expr.span.can_be_used_for_suggestions();
         if let Some(higher::Range {
             start,
             end: Some(end),
@@ -418,14 +358,7 @@ fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
         }) = higher::Range::hir(expr);
         if let Some(y) = y_plus_one(cx, end);
         then {
-            let span = if expr.span.from_expansion() {
-                expr.span
-                    .ctxt()
-                    .outer_expn_data()
-                    .call_site
-            } else {
-                expr.span
-            };
+            let span = expr.span;
             span_lint_and_then(
                 cx,
                 RANGE_PLUS_ONE,
@@ -460,6 +393,7 @@ fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
 // inclusive range minus one: `x..=(y-1)`
 fn check_inclusive_range_minus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
+        if expr.span.can_be_used_for_suggestions();
         if let Some(higher::Range { start, end: Some(end), limits: RangeLimits::Closed }) = higher::Range::hir(expr);
         if let Some(y) = y_minus_one(cx, end);
         then {
diff --git a/src/tools/clippy/clippy_lints/src/rc_clone_in_vec_init.rs b/src/tools/clippy/clippy_lints/src/rc_clone_in_vec_init.rs
index 8db8c4e9b787..e82aa3a7b989 100644
--- a/src/tools/clippy/clippy_lints/src/rc_clone_in_vec_init.rs
+++ b/src/tools/clippy/clippy_lints/src/rc_clone_in_vec_init.rs
@@ -41,7 +41,7 @@ declare_clippy_lint! {
     /// let data = std::rc::Rc::new("some data".to_string());
     /// let v = vec![data; 100];
     /// ```
-    #[clippy::version = "1.62.0"]
+    #[clippy::version = "1.63.0"]
     pub RC_CLONE_IN_VEC_INIT,
     suspicious,
     "initializing reference-counted pointer in `vec![elem; len]`"
diff --git a/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs b/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs
index 9538a8104739..94dec191103c 100644
--- a/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs
+++ b/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs
@@ -61,7 +61,7 @@ impl<'tcx> LateLintPass<'tcx> for ReadZeroByteVec {
                 // finds use of `_.read(&mut v)`
                 let mut read_found = false;
                 let mut visitor = expr_visitor_no_bodies(|expr| {
-                    if let ExprKind::MethodCall(path, [_self, arg], _) = expr.kind
+                    if let ExprKind::MethodCall(path, _self, [arg], _) = expr.kind
                         && let PathSegment { ident: read_or_read_exact, .. } = *path
                         && matches!(read_or_read_exact.as_str(), "read" | "read_exact")
                         && let ExprKind::AddrOf(_, hir::Mutability::Mut, inner) = arg.kind
diff --git a/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs b/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
index 323326381d40..3c6ca9d98975 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_pub_crate.rs
@@ -46,8 +46,8 @@ impl_lint_pass!(RedundantPubCrate => [REDUNDANT_PUB_CRATE]);
 impl<'tcx> LateLintPass<'tcx> for RedundantPubCrate {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
         if_chain! {
-            if cx.tcx.visibility(item.def_id) == ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id());
-            if !cx.access_levels.is_exported(item.def_id) && self.is_exported.last() == Some(&false);
+            if cx.tcx.visibility(item.def_id.def_id) == ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id());
+            if !cx.access_levels.is_exported(item.def_id.def_id) && self.is_exported.last() == Some(&false);
             if is_not_macro_export(item);
             then {
                 let span = item.span.with_hi(item.ident.span.hi());
@@ -70,7 +70,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantPubCrate {
         }
 
         if let ItemKind::Mod { .. } = item.kind {
-            self.is_exported.push(cx.access_levels.is_exported(item.def_id));
+            self.is_exported.push(cx.access_levels.is_exported(item.def_id.def_id));
         }
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/redundant_slicing.rs b/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
index db6c97f3739c..8693ca9af830 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
@@ -11,6 +11,8 @@ use rustc_middle::ty::adjustment::{Adjust, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::subst::GenericArg;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
+use std::iter;
+
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for redundant slicing expressions which use the full range, and
@@ -134,7 +136,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantSlicing {
                 } else if let Some(target_id) = cx.tcx.lang_items().deref_target() {
                     if let Ok(deref_ty) = cx.tcx.try_normalize_erasing_regions(
                         cx.param_env,
-                        cx.tcx.mk_projection(target_id, cx.tcx.mk_substs([GenericArg::from(indexed_ty)].into_iter())),
+                        cx.tcx.mk_projection(target_id, cx.tcx.mk_substs(iter::once(GenericArg::from(indexed_ty)))),
                     ) {
                         if deref_ty == expr_ty {
                             let snip = snippet_with_context(cx, indexed.span, ctxt, "..", &mut app).0;
diff --git a/src/tools/clippy/clippy_lints/src/redundant_static_lifetimes.rs b/src/tools/clippy/clippy_lints/src/redundant_static_lifetimes.rs
index f8801f769e83..2d751c274679 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_static_lifetimes.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_static_lifetimes.rs
@@ -48,15 +48,15 @@ impl_lint_pass!(RedundantStaticLifetimes => [REDUNDANT_STATIC_LIFETIMES]);
 
 impl RedundantStaticLifetimes {
     // Recursively visit types
-    fn visit_type(&mut self, ty: &Ty, cx: &EarlyContext<'_>, reason: &str) {
+    fn visit_type(ty: &Ty, cx: &EarlyContext<'_>, reason: &str) {
         match ty.kind {
             // Be careful of nested structures (arrays and tuples)
             TyKind::Array(ref ty, _) | TyKind::Slice(ref ty) => {
-                self.visit_type(ty, cx, reason);
+                Self::visit_type(ty, cx, reason);
             },
             TyKind::Tup(ref tup) => {
                 for tup_ty in tup {
-                    self.visit_type(tup_ty, cx, reason);
+                    Self::visit_type(tup_ty, cx, reason);
                 }
             },
             // This is what we are looking for !
@@ -87,7 +87,7 @@ impl RedundantStaticLifetimes {
                         _ => {},
                     }
                 }
-                self.visit_type(&borrow_type.ty, cx, reason);
+                Self::visit_type(&borrow_type.ty, cx, reason);
             },
             _ => {},
         }
@@ -102,13 +102,13 @@ impl EarlyLintPass for RedundantStaticLifetimes {
 
         if !item.span.from_expansion() {
             if let ItemKind::Const(_, ref var_type, _) = item.kind {
-                self.visit_type(var_type, cx, "constants have by default a `'static` lifetime");
+                Self::visit_type(var_type, cx, "constants have by default a `'static` lifetime");
                 // Don't check associated consts because `'static` cannot be elided on those (issue
                 // #2438)
             }
 
             if let ItemKind::Static(ref var_type, _, _) = item.kind {
-                self.visit_type(var_type, cx, "statics have by default a `'static` lifetime");
+                Self::visit_type(var_type, cx, "statics have by default a `'static` lifetime");
             }
         }
     }
diff --git a/src/tools/clippy/clippy_lints/src/ref_option_ref.rs b/src/tools/clippy/clippy_lints/src/ref_option_ref.rs
index 909d6971a549..42514f861be1 100644
--- a/src/tools/clippy/clippy_lints/src/ref_option_ref.rs
+++ b/src/tools/clippy/clippy_lints/src/ref_option_ref.rs
@@ -43,8 +43,7 @@ impl<'tcx> LateLintPass<'tcx> for RefOptionRef {
             if mut_ty.mutbl == Mutability::Not;
             if let TyKind::Path(ref qpath) = &mut_ty.ty.kind;
             let last = last_path_segment(qpath);
-            if let Some(res) = last.res;
-            if let Some(def_id) = res.opt_def_id();
+            if let Some(def_id) = last.res.opt_def_id();
 
             if cx.tcx.is_diagnostic_item(sym::Option, def_id);
             if let Some(params) = last_path_segment(qpath).args ;
diff --git a/src/tools/clippy/clippy_lints/src/renamed_lints.rs b/src/tools/clippy/clippy_lints/src/renamed_lints.rs
index 6bea6dc0773d..d320eea1c377 100644
--- a/src/tools/clippy/clippy_lints/src/renamed_lints.rs
+++ b/src/tools/clippy/clippy_lints/src/renamed_lints.rs
@@ -36,6 +36,7 @@ pub static RENAMED_LINTS: &[(&str, &str)] = &[
     ("clippy::invalid_ref", "invalid_value"),
     ("clippy::mem_discriminant_non_enum", "enum_intrinsics_non_enums"),
     ("clippy::panic_params", "non_fmt_panics"),
+    ("clippy::positional_named_format_parameters", "named_arguments_used_positionally"),
     ("clippy::temporary_cstring_as_ptr", "temporary_cstring_as_ptr"),
     ("clippy::unknown_clippy_lints", "unknown_lints"),
     ("clippy::unused_label", "unused_labels"),
diff --git a/src/tools/clippy/clippy_lints/src/repeat_once.rs b/src/tools/clippy/clippy_lints/src/repeat_once.rs
deleted file mode 100644
index 898c70ace66f..000000000000
--- a/src/tools/clippy/clippy_lints/src/repeat_once.rs
+++ /dev/null
@@ -1,89 +0,0 @@
-use clippy_utils::consts::{constant_context, Constant};
-use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet;
-use clippy_utils::ty::is_type_diagnostic_item;
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for usage of `.repeat(1)` and suggest the following method for each types.
-    /// - `.to_string()` for `str`
-    /// - `.clone()` for `String`
-    /// - `.to_vec()` for `slice`
-    ///
-    /// The lint will evaluate constant expressions and values as arguments of `.repeat(..)` and emit a message if
-    /// they are equivalent to `1`. (Related discussion in [rust-clippy#7306](https://github.com/rust-lang/rust-clippy/issues/7306))
-    ///
-    /// ### Why is this bad?
-    /// For example, `String.repeat(1)` is equivalent to `.clone()`. If cloning
-    /// the string is the intention behind this, `clone()` should be used.
-    ///
-    /// ### Example
-    /// ```rust
-    /// fn main() {
-    ///     let x = String::from("hello world").repeat(1);
-    /// }
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// fn main() {
-    ///     let x = String::from("hello world").clone();
-    /// }
-    /// ```
-    #[clippy::version = "1.47.0"]
-    pub REPEAT_ONCE,
-    complexity,
-    "using `.repeat(1)` instead of `String.clone()`, `str.to_string()` or `slice.to_vec()` "
-}
-
-declare_lint_pass!(RepeatOnce => [REPEAT_ONCE]);
-
-impl<'tcx> LateLintPass<'tcx> for RepeatOnce {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'tcx Expr<'_>) {
-        if_chain! {
-            if let ExprKind::MethodCall(path, [receiver, count], _) = &expr.kind;
-            if path.ident.name == sym!(repeat);
-            if constant_context(cx, cx.typeck_results()).expr(count) == Some(Constant::Int(1));
-            if !receiver.span.from_expansion();
-            then {
-                let ty = cx.typeck_results().expr_ty(receiver).peel_refs();
-                if ty.is_str() {
-                    span_lint_and_sugg(
-                        cx,
-                        REPEAT_ONCE,
-                        expr.span,
-                        "calling `repeat(1)` on str",
-                        "consider using `.to_string()` instead",
-                        format!("{}.to_string()", snippet(cx, receiver.span, r#""...""#)),
-                        Applicability::MachineApplicable,
-                    );
-                } else if ty.builtin_index().is_some() {
-                    span_lint_and_sugg(
-                        cx,
-                        REPEAT_ONCE,
-                        expr.span,
-                        "calling `repeat(1)` on slice",
-                        "consider using `.to_vec()` instead",
-                        format!("{}.to_vec()", snippet(cx, receiver.span, r#""...""#)),
-                        Applicability::MachineApplicable,
-                    );
-                } else if is_type_diagnostic_item(cx, ty, sym::String) {
-                    span_lint_and_sugg(
-                        cx,
-                        REPEAT_ONCE,
-                        expr.span,
-                        "calling `repeat(1)` on a string literal",
-                        "consider using `.clone()` instead",
-                        format!("{}.clone()", snippet(cx, receiver.span, r#""...""#)),
-                        Applicability::MachineApplicable,
-                    );
-                }
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs b/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs
index 60be6bd335f6..16d702a3868d 100644
--- a/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs
+++ b/src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs
@@ -128,7 +128,7 @@ impl<'tcx> LateLintPass<'tcx> for ReturnSelfNotMustUse {
 
     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'tcx>) {
         if let TraitItemKind::Fn(ref sig, _) = item.kind {
-            check_method(cx, sig.decl, item.def_id, item.span, item.hir_id());
+            check_method(cx, sig.decl, item.def_id.def_id, item.span, item.hir_id());
         }
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/returns.rs b/src/tools/clippy/clippy_lints/src/returns.rs
index 1d9a2abf7066..91553240e3c9 100644
--- a/src/tools/clippy/clippy_lints/src/returns.rs
+++ b/src/tools/clippy/clippy_lints/src/returns.rs
@@ -2,7 +2,6 @@ use clippy_utils::diagnostics::span_lint_hir_and_then;
 use clippy_utils::source::{snippet_opt, snippet_with_context};
 use clippy_utils::{fn_def_id, path_to_local_id};
 use if_chain::if_chain;
-use rustc_ast::ast::Attribute;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
 use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, HirId, MatchSource, PatKind, StmtKind};
@@ -11,7 +10,6 @@ use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
-use rustc_span::sym;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -141,7 +139,7 @@ impl<'tcx> LateLintPass<'tcx> for Return {
                 } else {
                     RetReplacement::Empty
                 };
-                check_final_expr(cx, &body.value, Some(body.value.span), replacement);
+                check_final_expr(cx, body.value, Some(body.value.span), replacement);
             },
             FnKind::ItemFn(..) | FnKind::Method(..) => {
                 if let ExprKind::Block(block, _) = body.value.kind {
@@ -152,10 +150,6 @@ impl<'tcx> LateLintPass<'tcx> for Return {
     }
 }
 
-fn attr_is_cfg(attr: &Attribute) -> bool {
-    attr.meta_item_list().is_some() && attr.has_name(sym::cfg)
-}
-
 fn check_block_return<'tcx>(cx: &LateContext<'tcx>, block: &Block<'tcx>) {
     if let Some(expr) = block.expr {
         check_final_expr(cx, expr, Some(expr.span), RetReplacement::Empty);
@@ -178,9 +172,7 @@ fn check_final_expr<'tcx>(
     match expr.kind {
         // simple return is always "bad"
         ExprKind::Ret(ref inner) => {
-            // allow `#[cfg(a)] return a; #[cfg(b)] return b;`
-            let attrs = cx.tcx.hir().attrs(expr.hir_id);
-            if !attrs.iter().any(attr_is_cfg) {
+            if cx.tcx.hir().attrs(expr.hir_id).is_empty() {
                 let borrows = inner.map_or(false, |inner| last_statement_borrows(cx, inner));
                 if !borrows {
                     emit_return_lint(
diff --git a/src/tools/clippy/clippy_lints/src/self_named_constructors.rs b/src/tools/clippy/clippy_lints/src/self_named_constructors.rs
index d07c26d7c897..1ac538f4c7c0 100644
--- a/src/tools/clippy/clippy_lints/src/self_named_constructors.rs
+++ b/src/tools/clippy/clippy_lints/src/self_named_constructors.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::return_ty;
-use clippy_utils::ty::{contains_adt_constructor, contains_ty};
+use clippy_utils::ty::contains_adt_constructor;
 use rustc_hir::{Impl, ImplItem, ImplItemKind, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -51,7 +51,7 @@ impl<'tcx> LateLintPass<'tcx> for SelfNamedConstructors {
             _ => return,
         }
 
-        let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+        let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
         let item = cx.tcx.hir().expect_item(parent);
         let self_ty = cx.tcx.type_of(item.def_id);
         let ret_ty = return_ty(cx, impl_item.hir_id());
@@ -66,7 +66,7 @@ impl<'tcx> LateLintPass<'tcx> for SelfNamedConstructors {
             if !contains_adt_constructor(ret_ty, self_adt) {
                 return;
             }
-        } else if !contains_ty(ret_ty, self_ty) {
+        } else if !ret_ty.contains(self_ty) {
             return;
         }
 
diff --git a/src/tools/clippy/clippy_lints/src/size_of_in_element_count.rs b/src/tools/clippy/clippy_lints/src/size_of_in_element_count.rs
index bfb9f0d01e1d..ac4e29e9dfdf 100644
--- a/src/tools/clippy/clippy_lints/src/size_of_in_element_count.rs
+++ b/src/tools/clippy/clippy_lints/src/size_of_in_element_count.rs
@@ -108,7 +108,7 @@ fn get_pointee_ty_and_count_expr<'tcx>(
     };
     if_chain! {
         // Find calls to copy_{from,to}{,_nonoverlapping} and write_bytes methods
-        if let ExprKind::MethodCall(method_path, [ptr_self, .., count], _) = expr.kind;
+        if let ExprKind::MethodCall(method_path, ptr_self, [.., count], _) = expr.kind;
         let method_ident = method_path.ident.as_str();
         if METHODS.iter().any(|m| *m == method_ident);
 
diff --git a/src/tools/clippy/clippy_lints/src/slow_vector_initialization.rs b/src/tools/clippy/clippy_lints/src/slow_vector_initialization.rs
index b59a25e3a400..c07aa00a1278 100644
--- a/src/tools/clippy/clippy_lints/src/slow_vector_initialization.rs
+++ b/src/tools/clippy/clippy_lints/src/slow_vector_initialization.rs
@@ -99,7 +99,7 @@ impl<'tcx> LateLintPass<'tcx> for SlowVectorInit {
         // Matches statements which initializes vectors. For example: `let mut vec = Vec::with_capacity(10)`
         if_chain! {
             if let StmtKind::Local(local) = stmt.kind;
-            if let PatKind::Binding(BindingAnnotation::Mutable, local_id, _, None) = local.pat.kind;
+            if let PatKind::Binding(BindingAnnotation::MUT, local_id, _, None) = local.pat.kind;
             if let Some(init) = local.init;
             if let Some(len_arg) = Self::is_vec_with_capacity(cx, init);
 
@@ -201,7 +201,7 @@ impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
     fn search_slow_extend_filling(&mut self, expr: &'tcx Expr<'_>) {
         if_chain! {
             if self.initialization_found;
-            if let ExprKind::MethodCall(path, [self_arg, extend_arg], _) = expr.kind;
+            if let ExprKind::MethodCall(path, self_arg, [extend_arg], _) = expr.kind;
             if path_to_local_id(self_arg, self.vec_alloc.local_id);
             if path.ident.name == sym!(extend);
             if self.is_repeat_take(extend_arg);
@@ -215,7 +215,7 @@ impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
     /// Checks if the given expression is resizing a vector with 0
     fn search_slow_resize_filling(&mut self, expr: &'tcx Expr<'_>) {
         if self.initialization_found
-            && let ExprKind::MethodCall(path, [self_arg, len_arg, fill_arg], _) = expr.kind
+            && let ExprKind::MethodCall(path, self_arg, [len_arg, fill_arg], _) = expr.kind
             && path_to_local_id(self_arg, self.vec_alloc.local_id)
             && path.ident.name == sym!(resize)
             // Check that is filled with 0
@@ -224,7 +224,7 @@ impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
                 // Check that len expression is equals to `with_capacity` expression
                 if SpanlessEq::new(self.cx).eq_expr(len_arg, self.vec_alloc.len_expr) {
                     self.slow_expression = Some(InitializationType::Resize(expr));
-                } else if let ExprKind::MethodCall(path, _, _) = len_arg.kind && path.ident.as_str() == "capacity" {
+                } else if let ExprKind::MethodCall(path, ..) = len_arg.kind && path.ident.as_str() == "capacity" {
                     self.slow_expression = Some(InitializationType::Resize(expr));
                 }
             }
@@ -233,7 +233,7 @@ impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
     /// Returns `true` if give expression is `repeat(0).take(...)`
     fn is_repeat_take(&self, expr: &Expr<'_>) -> bool {
         if_chain! {
-            if let ExprKind::MethodCall(take_path, [recv, len_arg, ..], _) = expr.kind;
+            if let ExprKind::MethodCall(take_path, recv, [len_arg, ..], _) = expr.kind;
             if take_path.ident.name == sym!(take);
             // Check that take is applied to `repeat(0)`
             if self.is_repeat_zero(recv);
@@ -241,7 +241,7 @@ impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
                 // Check that len expression is equals to `with_capacity` expression
                 if SpanlessEq::new(self.cx).eq_expr(len_arg, self.vec_alloc.len_expr) {
                     return true;
-                } else if let ExprKind::MethodCall(path, _, _) = len_arg.kind && path.ident.as_str() == "capacity" {
+                } else if let ExprKind::MethodCall(path, ..) = len_arg.kind && path.ident.as_str() == "capacity" {
                     return true;
                 }
             }
diff --git a/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs b/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs
deleted file mode 100644
index 6d54935f81ab..000000000000
--- a/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs
+++ /dev/null
@@ -1,144 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::{is_slice_of_primitives, sugg::Sugg};
-use if_chain::if_chain;
-use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// When sorting primitive values (integers, bools, chars, as well
-    /// as arrays, slices, and tuples of such items), it is typically better to
-    /// use an unstable sort than a stable sort.
-    ///
-    /// ### Why is this bad?
-    /// Typically, using a stable sort consumes more memory and cpu cycles.
-    /// Because values which compare equal are identical, preserving their
-    /// relative order (the guarantee that a stable sort provides) means
-    /// nothing, while the extra costs still apply.
-    ///
-    /// ### Known problems
-    ///
-    /// As pointed out in
-    /// [issue #8241](https://github.com/rust-lang/rust-clippy/issues/8241),
-    /// a stable sort can instead be significantly faster for certain scenarios
-    /// (eg. when a sorted vector is extended with new data and resorted).
-    ///
-    /// For more information and benchmarking results, please refer to the
-    /// issue linked above.
-    ///
-    /// ### Example
-    /// ```rust
-    /// let mut vec = vec![2, 1, 3];
-    /// vec.sort();
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// let mut vec = vec![2, 1, 3];
-    /// vec.sort_unstable();
-    /// ```
-    #[clippy::version = "1.47.0"]
-    pub STABLE_SORT_PRIMITIVE,
-    pedantic,
-    "use of sort() when sort_unstable() is equivalent"
-}
-
-declare_lint_pass!(StableSortPrimitive => [STABLE_SORT_PRIMITIVE]);
-
-/// The three "kinds" of sorts
-enum SortingKind {
-    Vanilla,
-    /* The other kinds of lint are currently commented out because they
-     * can map distinct values to equal ones. If the key function is
-     * provably one-to-one, or if the Cmp function conserves equality,
-     * then they could be linted on, but I don't know if we can check
-     * for that. */
-
-    /* ByKey,
-     * ByCmp, */
-}
-impl SortingKind {
-    /// The name of the stable version of this kind of sort
-    fn stable_name(&self) -> &str {
-        match self {
-            SortingKind::Vanilla => "sort",
-            /* SortingKind::ByKey => "sort_by_key",
-             * SortingKind::ByCmp => "sort_by", */
-        }
-    }
-    /// The name of the unstable version of this kind of sort
-    fn unstable_name(&self) -> &str {
-        match self {
-            SortingKind::Vanilla => "sort_unstable",
-            /* SortingKind::ByKey => "sort_unstable_by_key",
-             * SortingKind::ByCmp => "sort_unstable_by", */
-        }
-    }
-    /// Takes the name of a function call and returns the kind of sort
-    /// that corresponds to that function name (or None if it isn't)
-    fn from_stable_name(name: &str) -> Option<SortingKind> {
-        match name {
-            "sort" => Some(SortingKind::Vanilla),
-            // "sort_by" => Some(SortingKind::ByCmp),
-            // "sort_by_key" => Some(SortingKind::ByKey),
-            _ => None,
-        }
-    }
-}
-
-/// A detected instance of this lint
-struct LintDetection {
-    slice_name: String,
-    method: SortingKind,
-    method_args: String,
-    slice_type: String,
-}
-
-fn detect_stable_sort_primitive(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintDetection> {
-    if_chain! {
-        if let ExprKind::MethodCall(method_name, [slice, args @ ..], _) = &expr.kind;
-        if let Some(method) = SortingKind::from_stable_name(method_name.ident.name.as_str());
-        if let Some(slice_type) = is_slice_of_primitives(cx, slice);
-        then {
-            let args_str = args.iter().map(|arg| Sugg::hir(cx, arg, "..").to_string()).collect::<Vec<String>>().join(", ");
-            Some(LintDetection { slice_name: Sugg::hir(cx, slice, "..").to_string(), method, method_args: args_str, slice_type })
-        } else {
-            None
-        }
-    }
-}
-
-impl LateLintPass<'_> for StableSortPrimitive {
-    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if let Some(detection) = detect_stable_sort_primitive(cx, expr) {
-            span_lint_and_then(
-                cx,
-                STABLE_SORT_PRIMITIVE,
-                expr.span,
-                format!(
-                    "used `{}` on primitive type `{}`",
-                    detection.method.stable_name(),
-                    detection.slice_type,
-                )
-                .as_str(),
-                |diag| {
-                    diag.span_suggestion(
-                        expr.span,
-                        "try",
-                        format!(
-                            "{}.{}({})",
-                            detection.slice_name,
-                            detection.method.unstable_name(),
-                            detection.method_args,
-                        ),
-                        Applicability::MachineApplicable,
-                    );
-                    diag.note(
-                        "an unstable sort typically performs faster without any observable difference for this data type",
-                    );
-                },
-            );
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/strings.rs b/src/tools/clippy/clippy_lints/src/strings.rs
index 22eb06b36463..662d399ca538 100644
--- a/src/tools/clippy/clippy_lints/src/strings.rs
+++ b/src/tools/clippy/clippy_lints/src/strings.rs
@@ -262,7 +262,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
             let (method_names, expressions, _) = method_calls(left, 1);
             if method_names.len() == 1;
             if expressions.len() == 1;
-            if expressions[0].len() == 1;
+            if expressions[0].1.is_empty();
             if method_names[0] == sym!(as_bytes);
 
             // Check for slicer
@@ -270,7 +270,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
 
             then {
                 let mut applicability = Applicability::MachineApplicable;
-                let string_expression = &expressions[0][0];
+                let string_expression = &expressions[0].0;
 
                 let snippet_app = snippet_with_applicability(
                     cx,
@@ -291,12 +291,12 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
         }
 
         if_chain! {
-            if let ExprKind::MethodCall(path, args, _) = &e.kind;
+            if let ExprKind::MethodCall(path, receiver, ..) = &e.kind;
             if path.ident.name == sym!(as_bytes);
-            if let ExprKind::Lit(lit) = &args[0].kind;
+            if let ExprKind::Lit(lit) = &receiver.kind;
             if let LitKind::Str(lit_content, _) = &lit.node;
             then {
-                let callsite = snippet(cx, args[0].span.source_callsite(), r#""foo""#);
+                let callsite = snippet(cx, receiver.span.source_callsite(), r#""foo""#);
                 let mut applicability = Applicability::MachineApplicable;
                 if callsite.starts_with("include_str!") {
                     span_lint_and_sugg(
@@ -305,7 +305,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
                         e.span,
                         "calling `as_bytes()` on `include_str!(..)`",
                         "consider using `include_bytes!(..)` instead",
-                        snippet_with_applicability(cx, args[0].span, r#""foo""#, &mut applicability).replacen(
+                        snippet_with_applicability(cx, receiver.span, r#""foo""#, &mut applicability).replacen(
                             "include_str",
                             "include_bytes",
                             1,
@@ -314,7 +314,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
                     );
                 } else if lit_content.as_str().is_ascii()
                     && lit_content.as_str().len() <= MAX_LENGTH_BYTE_STRING_LIT
-                    && !args[0].span.from_expansion()
+                    && !receiver.span.from_expansion()
                 {
                     span_lint_and_sugg(
                         cx,
@@ -324,7 +324,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
                         "consider using a byte string literal instead",
                         format!(
                             "b{}",
-                            snippet_with_applicability(cx, args[0].span, r#""foo""#, &mut applicability)
+                            snippet_with_applicability(cx, receiver.span, r#""foo""#, &mut applicability)
                         ),
                         applicability,
                     );
@@ -333,9 +333,9 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
         }
 
         if_chain! {
-            if let ExprKind::MethodCall(path, [recv], _) = &e.kind;
+            if let ExprKind::MethodCall(path, recv, [], _) = &e.kind;
             if path.ident.name == sym!(into_bytes);
-            if let ExprKind::MethodCall(path, [recv], _) = &recv.kind;
+            if let ExprKind::MethodCall(path, recv, [], _) = &recv.kind;
             if matches!(path.ident.name.as_str(), "to_owned" | "to_string");
             if let ExprKind::Lit(lit) = &recv.kind;
             if let LitKind::Str(lit_content, _) = &lit.node;
@@ -393,7 +393,7 @@ declare_lint_pass!(StrToString => [STR_TO_STRING]);
 impl<'tcx> LateLintPass<'tcx> for StrToString {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'_>) {
         if_chain! {
-            if let ExprKind::MethodCall(path, [self_arg, ..], _) = &expr.kind;
+            if let ExprKind::MethodCall(path, self_arg, ..) = &expr.kind;
             if path.ident.name == sym::to_string;
             let ty = cx.typeck_results().expr_ty(self_arg);
             if let ty::Ref(_, ty, ..) = ty.kind();
@@ -443,7 +443,7 @@ declare_lint_pass!(StringToString => [STRING_TO_STRING]);
 impl<'tcx> LateLintPass<'tcx> for StringToString {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'_>) {
         if_chain! {
-            if let ExprKind::MethodCall(path, [self_arg, ..], _) = &expr.kind;
+            if let ExprKind::MethodCall(path, self_arg, ..) = &expr.kind;
             if path.ident.name == sym::to_string;
             let ty = cx.typeck_results().expr_ty(self_arg);
             if is_type_diagnostic_item(cx, ty, sym::String);
@@ -487,11 +487,11 @@ impl<'tcx> LateLintPass<'tcx> for TrimSplitWhitespace {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'_>) {
         let tyckres = cx.typeck_results();
         if_chain! {
-            if let ExprKind::MethodCall(path, [split_recv], split_ws_span) = expr.kind;
+            if let ExprKind::MethodCall(path, split_recv, [], split_ws_span) = expr.kind;
             if path.ident.name == sym!(split_whitespace);
             if let Some(split_ws_def_id) = tyckres.type_dependent_def_id(expr.hir_id);
             if cx.tcx.is_diagnostic_item(sym::str_split_whitespace, split_ws_def_id);
-            if let ExprKind::MethodCall(path, [_trim_recv], trim_span) = split_recv.kind;
+            if let ExprKind::MethodCall(path, _trim_recv, [], trim_span) = split_recv.kind;
             if let trim_fn_name @ ("trim" | "trim_start" | "trim_end") = path.ident.name.as_str();
             if let Some(trim_def_id) = tyckres.type_dependent_def_id(split_recv.hir_id);
             if is_one_of_trim_diagnostic_items(cx, trim_def_id);
diff --git a/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs b/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs
index 7bc9cf742e65..78403d9fdb7e 100644
--- a/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs
+++ b/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs
@@ -47,7 +47,7 @@ impl<'tcx> LateLintPass<'tcx> for StrlenOnCStrings {
             if let ExprKind::Path(path) = &func.kind;
             if let Some(did) = cx.qpath_res(path, func.hir_id).opt_def_id();
             if match_libc_symbol(cx, did, "strlen");
-            if let ExprKind::MethodCall(path, [self_arg], _) = recv.kind;
+            if let ExprKind::MethodCall(path, self_arg, [], _) = recv.kind;
             if !recv.span.from_expansion();
             if path.ident.name == sym::as_ptr;
             then {
diff --git a/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs b/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs
index 4294464dbf61..d47ed459387e 100644
--- a/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs
+++ b/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs
@@ -64,11 +64,11 @@ impl<'tcx> LateLintPass<'tcx> for SuspiciousImpl {
 
             // Check for more than one binary operation in the implemented function
             // Linting when multiple operations are involved can result in false positives
-            let parent_fn = cx.tcx.hir().get_parent_item(expr.hir_id);
+            let parent_fn = cx.tcx.hir().get_parent_item(expr.hir_id).def_id;
             if let hir::Node::ImplItem(impl_item) = cx.tcx.hir().get_by_def_id(parent_fn);
             if let hir::ImplItemKind::Fn(_, body_id) = impl_item.kind;
             let body = cx.tcx.hir().body(body_id);
-            let parent_fn = cx.tcx.hir().get_parent_item(expr.hir_id);
+            let parent_fn = cx.tcx.hir().get_parent_item(expr.hir_id).def_id;
             if let Some(trait_ref) = trait_ref_of_method(cx, parent_fn);
             let trait_id = trait_ref.path.res.def_id();
             if ![binop_trait_id, op_assign_trait_id].contains(&trait_id);
@@ -78,7 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for SuspiciousImpl {
             ]
                 .iter()
                 .find(|&(ts, _)| ts.iter().any(|&t| Ok(trait_id) == cx.tcx.lang_items().require(t)));
-            if count_binops(&body.value) == 1;
+            if count_binops(body.value) == 1;
             then {
                 span_lint(
                     cx,
diff --git a/src/tools/clippy/clippy_lints/src/to_digit_is_some.rs b/src/tools/clippy/clippy_lints/src/to_digit_is_some.rs
index aa6c01b3a7cd..651201f34ed2 100644
--- a/src/tools/clippy/clippy_lints/src/to_digit_is_some.rs
+++ b/src/tools/clippy/clippy_lints/src/to_digit_is_some.rs
@@ -39,19 +39,17 @@ declare_lint_pass!(ToDigitIsSome => [TO_DIGIT_IS_SOME]);
 impl<'tcx> LateLintPass<'tcx> for ToDigitIsSome {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
         if_chain! {
-            if let hir::ExprKind::MethodCall(is_some_path, is_some_args, _) = &expr.kind;
+            if let hir::ExprKind::MethodCall(is_some_path, to_digit_expr, [], _) = &expr.kind;
             if is_some_path.ident.name.as_str() == "is_some";
-            if let [to_digit_expr] = &**is_some_args;
             then {
                 let match_result = match &to_digit_expr.kind {
-                    hir::ExprKind::MethodCall(to_digits_path, to_digit_args, _) => {
+                    hir::ExprKind::MethodCall(to_digits_path, char_arg, [radix_arg], _) => {
                         if_chain! {
-                            if let [char_arg, radix_arg] = &**to_digit_args;
                             if to_digits_path.ident.name.as_str() == "to_digit";
                             let char_arg_ty = cx.typeck_results().expr_ty_adjusted(char_arg);
                             if *char_arg_ty.kind() == ty::Char;
                             then {
-                                Some((true, char_arg, radix_arg))
+                                Some((true, *char_arg, radix_arg))
                             } else {
                                 None
                             }
@@ -59,7 +57,7 @@ impl<'tcx> LateLintPass<'tcx> for ToDigitIsSome {
                     }
                     hir::ExprKind::Call(to_digits_call, to_digit_args) => {
                         if_chain! {
-                            if let [char_arg, radix_arg] = &**to_digit_args;
+                            if let [char_arg, radix_arg] = *to_digit_args;
                             if let hir::ExprKind::Path(to_digits_path) = &to_digits_call.kind;
                             if let to_digits_call_res = cx.qpath_res(to_digits_path, to_digits_call.hir_id);
                             if let Some(to_digits_def_id) = to_digits_call_res.opt_def_id();
diff --git a/src/tools/clippy/clippy_lints/src/trait_bounds.rs b/src/tools/clippy/clippy_lints/src/trait_bounds.rs
index 0a42a31fb8cf..a25be93b8d61 100644
--- a/src/tools/clippy/clippy_lints/src/trait_bounds.rs
+++ b/src/tools/clippy/clippy_lints/src/trait_bounds.rs
@@ -4,7 +4,7 @@ use clippy_utils::{SpanlessEq, SpanlessHash};
 use core::hash::{Hash, Hasher};
 use if_chain::if_chain;
 use itertools::Itertools;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
@@ -15,6 +15,7 @@ use rustc_hir::{
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{BytePos, Span};
+use std::collections::hash_map::Entry;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -103,7 +104,6 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
     fn check_generics(&mut self, cx: &LateContext<'tcx>, gen: &'tcx Generics<'_>) {
         self.check_type_repetition(cx, gen);
         check_trait_bound_duplication(cx, gen);
-        check_bounds_or_where_duplication(cx, gen);
     }
 
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
@@ -128,7 +128,7 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
                 if !bound_predicate.span.from_expansion();
                 if let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind;
                 if let Some(PathSegment {
-                    res: Some(Res::SelfTy{ trait_: Some(def_id), alias_to: _ }), ..
+                    res: Res::SelfTy{ trait_: Some(def_id), alias_to: _ }, ..
                 }) = segments.first();
                 if let Some(
                     Node::Item(
@@ -234,35 +234,61 @@ impl TraitBounds {
 }
 
 fn check_trait_bound_duplication(cx: &LateContext<'_>, gen: &'_ Generics<'_>) {
-    if gen.span.from_expansion() || gen.params.is_empty() || gen.predicates.is_empty() {
+    if gen.span.from_expansion() {
         return;
     }
 
-    let mut map = FxHashMap::<_, Vec<_>>::default();
-    for predicate in gen.predicates {
+    // Explanation:
+    // fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
+    // where T: Clone + Default, { unimplemented!(); }
+    //       ^^^^^^^^^^^^^^^^^^
+    //       |
+    // collects each of these where clauses into a set keyed by generic name and comparable trait
+    // eg. (T, Clone)
+    let where_predicates = gen
+        .predicates
+        .iter()
+        .filter_map(|pred| {
+            if_chain! {
+                if pred.in_where_clause();
+                if let WherePredicate::BoundPredicate(bound_predicate) = pred;
+                if let TyKind::Path(QPath::Resolved(_, path)) =  bound_predicate.bounded_ty.kind;
+                then {
+                    return Some(
+                        rollup_traits(cx, bound_predicate.bounds, "these where clauses contain repeated elements")
+                        .into_iter().map(|(trait_ref, _)| (path.res, trait_ref)))
+                }
+            }
+            None
+        })
+        .flatten()
+        .collect::<FxHashSet<_>>();
+
+    // Explanation:
+    // fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z) ...
+    //            ^^^^^^^^^^^^^^^^^^  ^^^^^^^
+    //            |
+    // compare trait bounds keyed by generic name and comparable trait to collected where
+    // predicates eg. (T, Clone)
+    for predicate in gen.predicates.iter().filter(|pred| !pred.in_where_clause()) {
         if_chain! {
-            if let WherePredicate::BoundPredicate(ref bound_predicate) = predicate;
+            if let WherePredicate::BoundPredicate(bound_predicate) = predicate;
             if bound_predicate.origin != PredicateOrigin::ImplTrait;
             if !bound_predicate.span.from_expansion();
-            if let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind;
-            if let Some(segment) = segments.first();
+            if let TyKind::Path(QPath::Resolved(_, path)) =  bound_predicate.bounded_ty.kind;
             then {
-                for (res_where, _, span_where) in bound_predicate.bounds.iter().filter_map(get_trait_info_from_bound) {
-                    let trait_resolutions_direct = map.entry(segment.ident).or_default();
-                    if let Some((_, span_direct)) = trait_resolutions_direct
-                                                .iter()
-                                                .find(|(res_direct, _)| *res_direct == res_where) {
+                let traits = rollup_traits(cx, bound_predicate.bounds, "these bounds contain repeated elements");
+                for (trait_ref, span) in traits {
+                    let key = (path.res, trait_ref);
+                    if where_predicates.contains(&key) {
                         span_lint_and_help(
                             cx,
                             TRAIT_DUPLICATION_IN_BOUNDS,
-                            *span_direct,
+                            span,
                             "this trait bound is already specified in the where clause",
                             None,
                             "consider removing this trait bound",
-                        );
-                    }
-                    else {
-                        trait_resolutions_direct.push((res_where, span_where));
+                            );
                     }
                 }
             }
@@ -270,23 +296,11 @@ fn check_trait_bound_duplication(cx: &LateContext<'_>, gen: &'_ Generics<'_>) {
     }
 }
 
-#[derive(PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, PartialEq, Eq, Hash, Debug)]
 struct ComparableTraitRef(Res, Vec<Res>);
-
-fn check_bounds_or_where_duplication(cx: &LateContext<'_>, gen: &'_ Generics<'_>) {
-    if gen.span.from_expansion() {
-        return;
-    }
-
-    for predicate in gen.predicates {
-        if let WherePredicate::BoundPredicate(ref bound_predicate) = predicate {
-            let msg = if predicate.in_where_clause() {
-                "these where clauses contain repeated elements"
-            } else {
-                "these bounds contain repeated elements"
-            };
-            rollup_traits(cx, bound_predicate.bounds, msg);
-        }
+impl Default for ComparableTraitRef {
+    fn default() -> Self {
+        Self(Res::Err, Vec::new())
     }
 }
 
@@ -331,7 +345,7 @@ fn into_comparable_trait_ref(trait_ref: &TraitRef<'_>) -> ComparableTraitRef {
     )
 }
 
-fn rollup_traits(cx: &LateContext<'_>, bounds: &[GenericBound<'_>], msg: &str) {
+fn rollup_traits(cx: &LateContext<'_>, bounds: &[GenericBound<'_>], msg: &str) -> Vec<(ComparableTraitRef, Span)> {
     let mut map = FxHashMap::default();
     let mut repeated_res = false;
 
@@ -343,23 +357,33 @@ fn rollup_traits(cx: &LateContext<'_>, bounds: &[GenericBound<'_>], msg: &str) {
         }
     };
 
+    let mut i = 0usize;
     for bound in bounds.iter().filter_map(only_comparable_trait_refs) {
         let (comparable_bound, span_direct) = bound;
-        if map.insert(comparable_bound, span_direct).is_some() {
-            repeated_res = true;
+        match map.entry(comparable_bound) {
+            Entry::Occupied(_) => repeated_res = true,
+            Entry::Vacant(e) => {
+                e.insert((span_direct, i));
+                i += 1;
+            },
         }
     }
 
+    // Put bounds in source order
+    let mut comparable_bounds = vec![Default::default(); map.len()];
+    for (k, (v, i)) in map {
+        comparable_bounds[i] = (k, v);
+    }
+
     if_chain! {
         if repeated_res;
         if let [first_trait, .., last_trait] = bounds;
         then {
             let all_trait_span = first_trait.span().to(last_trait.span());
 
-            let mut traits = map.values()
-                .filter_map(|span| snippet_opt(cx, *span))
+            let traits = comparable_bounds.iter()
+                .filter_map(|&(_, span)| snippet_opt(cx, span))
                 .collect::<Vec<_>>();
-            traits.sort_unstable();
             let traits = traits.join(" + ");
 
             span_lint_and_sugg(
@@ -373,4 +397,6 @@ fn rollup_traits(cx: &LateContext<'_>, bounds: &[GenericBound<'_>], msg: &str) {
             );
         }
     }
+
+    comparable_bounds
 }
diff --git a/src/tools/clippy/clippy_lints/src/transmute/mod.rs b/src/tools/clippy/clippy_lints/src/transmute/mod.rs
index 5f3e98144f42..424a6e9264e4 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/mod.rs
@@ -9,6 +9,7 @@ mod transmute_ptr_to_ref;
 mod transmute_ref_to_ref;
 mod transmute_undefined_repr;
 mod transmutes_expressible_as_ptr_casts;
+mod transmuting_null;
 mod unsound_collection_transmute;
 mod useless_transmute;
 mod utils;
@@ -386,6 +387,28 @@ declare_clippy_lint! {
     "transmute to or from a type with an undefined representation"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for transmute calls which would receive a null pointer.
+    ///
+    /// ### Why is this bad?
+    /// Transmuting a null pointer is undefined behavior.
+    ///
+    /// ### Known problems
+    /// Not all cases can be detected at the moment of this writing.
+    /// For example, variables which hold a null pointer and are then fed to a `transmute`
+    /// call, aren't detectable yet.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let null_ref: &u64 = unsafe { std::mem::transmute(0 as *const u64) };
+    /// ```
+    #[clippy::version = "1.35.0"]
+    pub TRANSMUTING_NULL,
+    correctness,
+    "transmutes from a null pointer to a reference, which is undefined behavior"
+}
+
 pub struct Transmute {
     msrv: Option<RustcVersion>,
 }
@@ -404,6 +427,7 @@ impl_lint_pass!(Transmute => [
     UNSOUND_COLLECTION_TRANSMUTE,
     TRANSMUTES_EXPRESSIBLE_AS_PTR_CASTS,
     TRANSMUTE_UNDEFINED_REPR,
+    TRANSMUTING_NULL,
 ]);
 impl Transmute {
     #[must_use]
@@ -436,6 +460,7 @@ impl<'tcx> LateLintPass<'tcx> for Transmute {
 
                 let linted = wrong_transmute::check(cx, e, from_ty, to_ty)
                     | crosspointer_transmute::check(cx, e, from_ty, to_ty)
+                    | transmuting_null::check(cx, e, arg, to_ty)
                     | transmute_ptr_to_ref::check(cx, e, from_ty, to_ty, arg, path, self.msrv)
                     | transmute_int_to_char::check(cx, e, from_ty, to_ty, arg, const_context)
                     | transmute_ref_to_ref::check(cx, e, from_ty, to_ty, arg, const_context)
diff --git a/src/tools/clippy/clippy_lints/src/transmute/transmute_undefined_repr.rs b/src/tools/clippy/clippy_lints/src/transmute/transmute_undefined_repr.rs
index 20b348fc14f7..ae55a6bf5586 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/transmute_undefined_repr.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/transmute_undefined_repr.rs
@@ -3,11 +3,11 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::ty::is_c_void;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
-use rustc_middle::ty::subst::{Subst, SubstsRef};
+use rustc_middle::ty::SubstsRef;
 use rustc_middle::ty::{self, IntTy, Ty, TypeAndMut, UintTy};
-use rustc_span::Span;
+use rustc_span::DUMMY_SP;
 
-#[allow(clippy::too_many_lines)]
+#[expect(clippy::too_many_lines)]
 pub(super) fn check<'tcx>(
     cx: &LateContext<'tcx>,
     e: &'tcx Expr<'_>,
@@ -18,116 +18,89 @@ pub(super) fn check<'tcx>(
     let mut to_ty = cx.tcx.erase_regions(to_ty_orig);
 
     while from_ty != to_ty {
-        match reduce_refs(cx, e.span, from_ty, to_ty) {
-            ReducedTys::FromFatPtr {
-                unsized_ty,
-                to_ty: to_sub_ty,
-            } => match reduce_ty(cx, to_sub_ty) {
-                ReducedTy::TypeErasure => break,
-                ReducedTy::UnorderedFields(ty) if is_size_pair(ty) => break,
-                ReducedTy::Ref(to_sub_ty) => {
-                    from_ty = unsized_ty;
-                    to_ty = to_sub_ty;
-                    continue;
-                },
-                _ => {
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!("transmute from `{}` which has an undefined layout", from_ty_orig),
-                        |diag| {
-                            if from_ty_orig.peel_refs() != unsized_ty {
-                                diag.note(&format!("the contained type `&{}` has an undefined layout", unsized_ty));
-                            }
-                        },
-                    );
-                    return true;
-                },
+        let reduced_tys = reduce_refs(cx, from_ty, to_ty);
+        match (reduce_ty(cx, reduced_tys.from_ty), reduce_ty(cx, reduced_tys.to_ty)) {
+            // Various forms of type erasure.
+            (ReducedTy::TypeErasure { raw_ptr_only: false }, _)
+            | (_, ReducedTy::TypeErasure { raw_ptr_only: false }) => return false,
+            (ReducedTy::TypeErasure { .. }, _) if reduced_tys.from_raw_ptr => return false,
+            (_, ReducedTy::TypeErasure { .. }) if reduced_tys.to_raw_ptr => return false,
+
+            // `Repr(C)` <-> unordered type.
+            // If the first field of the `Repr(C)` type matches then the transmute is ok
+            (ReducedTy::OrderedFields(_, Some(from_sub_ty)), ReducedTy::UnorderedFields(to_sub_ty))
+            | (ReducedTy::UnorderedFields(from_sub_ty), ReducedTy::OrderedFields(_, Some(to_sub_ty))) => {
+                from_ty = from_sub_ty;
+                to_ty = to_sub_ty;
+                continue;
             },
-            ReducedTys::ToFatPtr {
-                unsized_ty,
-                from_ty: from_sub_ty,
-            } => match reduce_ty(cx, from_sub_ty) {
-                ReducedTy::TypeErasure => break,
-                ReducedTy::UnorderedFields(ty) if is_size_pair(ty) => break,
-                ReducedTy::Ref(from_sub_ty) => {
-                    from_ty = from_sub_ty;
-                    to_ty = unsized_ty;
-                    continue;
-                },
-                _ => {
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!("transmute to `{}` which has an undefined layout", to_ty_orig),
-                        |diag| {
-                            if to_ty_orig.peel_refs() != unsized_ty {
-                                diag.note(&format!("the contained type `&{}` has an undefined layout", unsized_ty));
-                            }
-                        },
-                    );
-                    return true;
-                },
+            (ReducedTy::OrderedFields(_, Some(from_sub_ty)), ReducedTy::Other(to_sub_ty)) if reduced_tys.to_fat_ptr => {
+                from_ty = from_sub_ty;
+                to_ty = to_sub_ty;
+                continue;
             },
-            ReducedTys::ToPtr {
-                from_ty: from_sub_ty,
-                to_ty: to_sub_ty,
-            } => match reduce_ty(cx, from_sub_ty) {
-                ReducedTy::UnorderedFields(from_ty) => {
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!("transmute from `{}` which has an undefined layout", from_ty_orig),
-                        |diag| {
-                            if from_ty_orig.peel_refs() != from_ty {
-                                diag.note(&format!("the contained type `{}` has an undefined layout", from_ty));
-                            }
-                        },
-                    );
-                    return true;
-                },
-                ReducedTy::Ref(from_sub_ty) => {
-                    from_ty = from_sub_ty;
-                    to_ty = to_sub_ty;
-                    continue;
-                },
-                _ => break,
+            (ReducedTy::Other(from_sub_ty), ReducedTy::OrderedFields(_, Some(to_sub_ty)))
+                if reduced_tys.from_fat_ptr =>
+            {
+                from_ty = from_sub_ty;
+                to_ty = to_sub_ty;
+                continue;
             },
-            ReducedTys::FromPtr {
-                from_ty: from_sub_ty,
-                to_ty: to_sub_ty,
-            } => match reduce_ty(cx, to_sub_ty) {
-                ReducedTy::UnorderedFields(to_ty) => {
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!("transmute to `{}` which has an undefined layout", to_ty_orig),
-                        |diag| {
-                            if to_ty_orig.peel_refs() != to_ty {
-                                diag.note(&format!("the contained type `{}` has an undefined layout", to_ty));
-                            }
-                        },
-                    );
-                    return true;
-                },
-                ReducedTy::Ref(to_sub_ty) => {
-                    from_ty = from_sub_ty;
-                    to_ty = to_sub_ty;
-                    continue;
-                },
-                _ => break,
+
+            // ptr <-> ptr
+            (ReducedTy::Other(from_sub_ty), ReducedTy::Other(to_sub_ty))
+                if matches!(from_sub_ty.kind(), ty::Ref(..) | ty::RawPtr(_))
+                    && matches!(to_sub_ty.kind(), ty::Ref(..) | ty::RawPtr(_)) =>
+            {
+                from_ty = from_sub_ty;
+                to_ty = to_sub_ty;
+                continue;
             },
-            ReducedTys::Other {
-                from_ty: from_sub_ty,
-                to_ty: to_sub_ty,
-            } => match (reduce_ty(cx, from_sub_ty), reduce_ty(cx, to_sub_ty)) {
-                (ReducedTy::TypeErasure, _) | (_, ReducedTy::TypeErasure) => return false,
-                (ReducedTy::UnorderedFields(from_ty), ReducedTy::UnorderedFields(to_ty)) if from_ty != to_ty => {
-                    let same_adt_did = if let (ty::Adt(from_def, from_subs), ty::Adt(to_def, to_subs))
+
+            // fat ptr <-> (*size, *size)
+            (ReducedTy::Other(_), ReducedTy::UnorderedFields(to_ty))
+                if reduced_tys.from_fat_ptr && is_size_pair(to_ty) =>
+            {
+                return false;
+            },
+            (ReducedTy::UnorderedFields(from_ty), ReducedTy::Other(_))
+                if reduced_tys.to_fat_ptr && is_size_pair(from_ty) =>
+            {
+                return false;
+            },
+
+            // fat ptr -> some struct | some struct -> fat ptr
+            (ReducedTy::Other(_), _) if reduced_tys.from_fat_ptr => {
+                span_lint_and_then(
+                    cx,
+                    TRANSMUTE_UNDEFINED_REPR,
+                    e.span,
+                    &format!("transmute from `{}` which has an undefined layout", from_ty_orig),
+                    |diag| {
+                        if from_ty_orig.peel_refs() != from_ty.peel_refs() {
+                            diag.note(&format!("the contained type `{}` has an undefined layout", from_ty));
+                        }
+                    },
+                );
+                return true;
+            },
+            (_, ReducedTy::Other(_)) if reduced_tys.to_fat_ptr => {
+                span_lint_and_then(
+                    cx,
+                    TRANSMUTE_UNDEFINED_REPR,
+                    e.span,
+                    &format!("transmute to `{}` which has an undefined layout", to_ty_orig),
+                    |diag| {
+                        if to_ty_orig.peel_refs() != to_ty.peel_refs() {
+                            diag.note(&format!("the contained type `{}` has an undefined layout", to_ty));
+                        }
+                    },
+                );
+                return true;
+            },
+
+            (ReducedTy::UnorderedFields(from_ty), ReducedTy::UnorderedFields(to_ty)) if from_ty != to_ty => {
+                let same_adt_did = if let (ty::Adt(from_def, from_subs), ty::Adt(to_def, to_subs))
                         = (from_ty.kind(), to_ty.kind())
                         && from_def == to_def
                     {
@@ -138,79 +111,72 @@ pub(super) fn check<'tcx>(
                     } else {
                         None
                     };
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!(
-                            "transmute from `{}` to `{}`, both of which have an undefined layout",
-                            from_ty_orig, to_ty_orig
-                        ),
-                        |diag| {
-                            if let Some(same_adt_did) = same_adt_did {
-                                diag.note(&format!(
-                                    "two instances of the same generic type (`{}`) may have different layouts",
-                                    cx.tcx.item_name(same_adt_did)
-                                ));
-                            } else {
-                                if from_ty_orig.peel_refs() != from_ty {
-                                    diag.note(&format!("the contained type `{}` has an undefined layout", from_ty));
-                                }
-                                if to_ty_orig.peel_refs() != to_ty {
-                                    diag.note(&format!("the contained type `{}` has an undefined layout", to_ty));
-                                }
-                            }
-                        },
-                    );
-                    return true;
-                },
-                (
-                    ReducedTy::UnorderedFields(from_ty),
-                    ReducedTy::Other(_) | ReducedTy::OrderedFields(_) | ReducedTy::Ref(_),
-                ) => {
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!("transmute from `{}` which has an undefined layout", from_ty_orig),
-                        |diag| {
+                span_lint_and_then(
+                    cx,
+                    TRANSMUTE_UNDEFINED_REPR,
+                    e.span,
+                    &format!(
+                        "transmute from `{}` to `{}`, both of which have an undefined layout",
+                        from_ty_orig, to_ty_orig
+                    ),
+                    |diag| {
+                        if let Some(same_adt_did) = same_adt_did {
+                            diag.note(&format!(
+                                "two instances of the same generic type (`{}`) may have different layouts",
+                                cx.tcx.item_name(same_adt_did)
+                            ));
+                        } else {
                             if from_ty_orig.peel_refs() != from_ty {
                                 diag.note(&format!("the contained type `{}` has an undefined layout", from_ty));
                             }
-                        },
-                    );
-                    return true;
-                },
-                (
-                    ReducedTy::Other(_) | ReducedTy::OrderedFields(_) | ReducedTy::Ref(_),
-                    ReducedTy::UnorderedFields(to_ty),
-                ) => {
-                    span_lint_and_then(
-                        cx,
-                        TRANSMUTE_UNDEFINED_REPR,
-                        e.span,
-                        &format!("transmute into `{}` which has an undefined layout", to_ty_orig),
-                        |diag| {
                             if to_ty_orig.peel_refs() != to_ty {
                                 diag.note(&format!("the contained type `{}` has an undefined layout", to_ty));
                             }
-                        },
-                    );
-                    return true;
-                },
-                (ReducedTy::Ref(from_sub_ty), ReducedTy::Ref(to_sub_ty)) => {
-                    from_ty = from_sub_ty;
-                    to_ty = to_sub_ty;
-                    continue;
-                },
-                (
-                    ReducedTy::OrderedFields(_) | ReducedTy::Ref(_) | ReducedTy::Other(_) | ReducedTy::Param,
-                    ReducedTy::OrderedFields(_) | ReducedTy::Ref(_) | ReducedTy::Other(_) | ReducedTy::Param,
-                )
-                | (
-                    ReducedTy::UnorderedFields(_) | ReducedTy::Param,
-                    ReducedTy::UnorderedFields(_) | ReducedTy::Param,
-                ) => break,
+                        }
+                    },
+                );
+                return true;
+            },
+            (
+                ReducedTy::UnorderedFields(from_ty),
+                ReducedTy::Other(_) | ReducedTy::OrderedFields(..) | ReducedTy::TypeErasure { raw_ptr_only: true },
+            ) => {
+                span_lint_and_then(
+                    cx,
+                    TRANSMUTE_UNDEFINED_REPR,
+                    e.span,
+                    &format!("transmute from `{}` which has an undefined layout", from_ty_orig),
+                    |diag| {
+                        if from_ty_orig.peel_refs() != from_ty {
+                            diag.note(&format!("the contained type `{}` has an undefined layout", from_ty));
+                        }
+                    },
+                );
+                return true;
+            },
+            (
+                ReducedTy::Other(_) | ReducedTy::OrderedFields(..) | ReducedTy::TypeErasure { raw_ptr_only: true },
+                ReducedTy::UnorderedFields(to_ty),
+            ) => {
+                span_lint_and_then(
+                    cx,
+                    TRANSMUTE_UNDEFINED_REPR,
+                    e.span,
+                    &format!("transmute into `{}` which has an undefined layout", to_ty_orig),
+                    |diag| {
+                        if to_ty_orig.peel_refs() != to_ty {
+                            diag.note(&format!("the contained type `{}` has an undefined layout", to_ty));
+                        }
+                    },
+                );
+                return true;
+            },
+            (
+                ReducedTy::OrderedFields(..) | ReducedTy::Other(_) | ReducedTy::TypeErasure { raw_ptr_only: true },
+                ReducedTy::OrderedFields(..) | ReducedTy::Other(_) | ReducedTy::TypeErasure { raw_ptr_only: true },
+            )
+            | (ReducedTy::UnorderedFields(_), ReducedTy::UnorderedFields(_)) => {
+                break;
             },
         }
     }
@@ -218,64 +184,64 @@ pub(super) fn check<'tcx>(
     false
 }
 
-enum ReducedTys<'tcx> {
-    FromFatPtr { unsized_ty: Ty<'tcx>, to_ty: Ty<'tcx> },
-    ToFatPtr { unsized_ty: Ty<'tcx>, from_ty: Ty<'tcx> },
-    ToPtr { from_ty: Ty<'tcx>, to_ty: Ty<'tcx> },
-    FromPtr { from_ty: Ty<'tcx>, to_ty: Ty<'tcx> },
-    Other { from_ty: Ty<'tcx>, to_ty: Ty<'tcx> },
+#[expect(clippy::struct_excessive_bools)]
+struct ReducedTys<'tcx> {
+    from_ty: Ty<'tcx>,
+    to_ty: Ty<'tcx>,
+    from_raw_ptr: bool,
+    to_raw_ptr: bool,
+    from_fat_ptr: bool,
+    to_fat_ptr: bool,
 }
 
 /// Remove references so long as both types are references.
-fn reduce_refs<'tcx>(
-    cx: &LateContext<'tcx>,
-    span: Span,
-    mut from_ty: Ty<'tcx>,
-    mut to_ty: Ty<'tcx>,
-) -> ReducedTys<'tcx> {
-    loop {
-        return match (from_ty.kind(), to_ty.kind()) {
+fn reduce_refs<'tcx>(cx: &LateContext<'tcx>, mut from_ty: Ty<'tcx>, mut to_ty: Ty<'tcx>) -> ReducedTys<'tcx> {
+    let mut from_raw_ptr = false;
+    let mut to_raw_ptr = false;
+    let (from_fat_ptr, to_fat_ptr) = loop {
+        break match (from_ty.kind(), to_ty.kind()) {
             (
                 &(ty::Ref(_, from_sub_ty, _) | ty::RawPtr(TypeAndMut { ty: from_sub_ty, .. })),
                 &(ty::Ref(_, to_sub_ty, _) | ty::RawPtr(TypeAndMut { ty: to_sub_ty, .. })),
             ) => {
+                from_raw_ptr = matches!(*from_ty.kind(), ty::RawPtr(_));
                 from_ty = from_sub_ty;
+                to_raw_ptr = matches!(*to_ty.kind(), ty::RawPtr(_));
                 to_ty = to_sub_ty;
                 continue;
             },
             (&(ty::Ref(_, unsized_ty, _) | ty::RawPtr(TypeAndMut { ty: unsized_ty, .. })), _)
-                if !unsized_ty.is_sized(cx.tcx.at(span), cx.param_env) =>
+                if !unsized_ty.is_sized(cx.tcx.at(DUMMY_SP), cx.param_env) =>
             {
-                ReducedTys::FromFatPtr { unsized_ty, to_ty }
+                (true, false)
             },
             (_, &(ty::Ref(_, unsized_ty, _) | ty::RawPtr(TypeAndMut { ty: unsized_ty, .. })))
-                if !unsized_ty.is_sized(cx.tcx.at(span), cx.param_env) =>
+                if !unsized_ty.is_sized(cx.tcx.at(DUMMY_SP), cx.param_env) =>
             {
-                ReducedTys::ToFatPtr { unsized_ty, from_ty }
+                (false, true)
             },
-            (&(ty::Ref(_, from_ty, _) | ty::RawPtr(TypeAndMut { ty: from_ty, .. })), _) => {
-                ReducedTys::FromPtr { from_ty, to_ty }
-            },
-            (_, &(ty::Ref(_, to_ty, _) | ty::RawPtr(TypeAndMut { ty: to_ty, .. }))) => {
-                ReducedTys::ToPtr { from_ty, to_ty }
-            },
-            _ => ReducedTys::Other { from_ty, to_ty },
+            _ => (false, false),
         };
+    };
+    ReducedTys {
+        from_ty,
+        to_ty,
+        from_raw_ptr,
+        to_raw_ptr,
+        from_fat_ptr,
+        to_fat_ptr,
     }
 }
 
 enum ReducedTy<'tcx> {
     /// The type can be used for type erasure.
-    TypeErasure,
+    TypeErasure { raw_ptr_only: bool },
     /// The type is a struct containing either zero non-zero sized fields, or multiple non-zero
     /// sized fields with a defined order.
-    OrderedFields(Ty<'tcx>),
+    /// The second value is the first non-zero sized type.
+    OrderedFields(Ty<'tcx>, Option<Ty<'tcx>>),
     /// The type is a struct containing multiple non-zero sized fields with no defined order.
     UnorderedFields(Ty<'tcx>),
-    /// The type is a reference to the contained type.
-    Ref(Ty<'tcx>),
-    /// The type is a generic parameter.
-    Param,
     /// Any other type.
     Other(Ty<'tcx>),
 }
@@ -285,16 +251,18 @@ fn reduce_ty<'tcx>(cx: &LateContext<'tcx>, mut ty: Ty<'tcx>) -> ReducedTy<'tcx>
     loop {
         ty = cx.tcx.try_normalize_erasing_regions(cx.param_env, ty).unwrap_or(ty);
         return match *ty.kind() {
-            ty::Array(sub_ty, _) if matches!(sub_ty.kind(), ty::Int(_) | ty::Uint(_)) => ReducedTy::TypeErasure,
+            ty::Array(sub_ty, _) if matches!(sub_ty.kind(), ty::Int(_) | ty::Uint(_)) => {
+                ReducedTy::TypeErasure { raw_ptr_only: false }
+            },
             ty::Array(sub_ty, _) | ty::Slice(sub_ty) => {
                 ty = sub_ty;
                 continue;
             },
-            ty::Tuple(args) if args.is_empty() => ReducedTy::TypeErasure,
+            ty::Tuple(args) if args.is_empty() => ReducedTy::TypeErasure { raw_ptr_only: false },
             ty::Tuple(args) => {
                 let mut iter = args.iter();
                 let Some(sized_ty) = iter.find(|&ty| !is_zero_sized_ty(cx, ty)) else {
-                    return ReducedTy::OrderedFields(ty);
+                    return ReducedTy::OrderedFields(ty, None);
                 };
                 if iter.all(|ty| is_zero_sized_ty(cx, ty)) {
                     ty = sized_ty;
@@ -309,27 +277,25 @@ fn reduce_ty<'tcx>(cx: &LateContext<'tcx>, mut ty: Ty<'tcx>) -> ReducedTy<'tcx>
                     .iter()
                     .map(|f| cx.tcx.bound_type_of(f.did).subst(cx.tcx, substs));
                 let Some(sized_ty) = iter.find(|&ty| !is_zero_sized_ty(cx, ty)) else {
-                    return ReducedTy::TypeErasure;
+                    return ReducedTy::TypeErasure { raw_ptr_only: false };
                 };
                 if iter.all(|ty| is_zero_sized_ty(cx, ty)) {
                     ty = sized_ty;
                     continue;
                 }
                 if def.repr().inhibit_struct_field_reordering_opt() {
-                    ReducedTy::OrderedFields(ty)
+                    ReducedTy::OrderedFields(ty, Some(sized_ty))
                 } else {
                     ReducedTy::UnorderedFields(ty)
                 }
             },
             ty::Adt(def, _) if def.is_enum() && (def.variants().is_empty() || is_c_void(cx, ty)) => {
-                ReducedTy::TypeErasure
+                ReducedTy::TypeErasure { raw_ptr_only: false }
             },
             // TODO: Check if the conversion to or from at least one of a union's fields is valid.
-            ty::Adt(def, _) if def.is_union() => ReducedTy::TypeErasure,
-            ty::Foreign(_) => ReducedTy::TypeErasure,
-            ty::Ref(_, ty, _) => ReducedTy::Ref(ty),
-            ty::RawPtr(ty) => ReducedTy::Ref(ty.ty),
-            ty::Param(_) => ReducedTy::Param,
+            ty::Adt(def, _) if def.is_union() => ReducedTy::TypeErasure { raw_ptr_only: false },
+            ty::Foreign(_) | ty::Param(_) => ReducedTy::TypeErasure { raw_ptr_only: false },
+            ty::Int(_) | ty::Uint(_) => ReducedTy::TypeErasure { raw_ptr_only: true },
             _ => ReducedTy::Other(ty),
         };
     }
diff --git a/src/tools/clippy/clippy_lints/src/transmute/transmuting_null.rs b/src/tools/clippy/clippy_lints/src/transmute/transmuting_null.rs
new file mode 100644
index 000000000000..d8e349af7af8
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/transmute/transmuting_null.rs
@@ -0,0 +1,61 @@
+use clippy_utils::consts::{constant_context, Constant};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::is_path_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::LitKind;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::Ty;
+use rustc_span::symbol::sym;
+
+use super::TRANSMUTING_NULL;
+
+const LINT_MSG: &str = "transmuting a known null pointer into a reference";
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arg: &'tcx Expr<'_>, to_ty: Ty<'tcx>) -> bool {
+    if !to_ty.is_ref() {
+        return false;
+    }
+
+    // Catching transmute over constants that resolve to `null`.
+    let mut const_eval_context = constant_context(cx, cx.typeck_results());
+    if_chain! {
+        if let ExprKind::Path(ref _qpath) = arg.kind;
+        if let Some(Constant::RawPtr(x)) = const_eval_context.expr(arg);
+        if x == 0;
+        then {
+            span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG);
+            return true;
+        }
+    }
+
+    // Catching:
+    // `std::mem::transmute(0 as *const i32)`
+    if_chain! {
+        if let ExprKind::Cast(inner_expr, _cast_ty) = arg.kind;
+        if let ExprKind::Lit(ref lit) = inner_expr.kind;
+        if let LitKind::Int(0, _) = lit.node;
+        then {
+            span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG);
+            return true;
+        }
+    }
+
+    // Catching:
+    // `std::mem::transmute(std::ptr::null::<i32>())`
+    if_chain! {
+        if let ExprKind::Call(func1, []) = arg.kind;
+        if is_path_diagnostic_item(cx, func1, sym::ptr_null);
+        then {
+            span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG);
+            return true;
+        }
+    }
+
+    // FIXME:
+    // Also catch transmutations of variables which are known nulls.
+    // To do this, MIR const propagation seems to be the better tool.
+    // Whenever MIR const prop routines are more developed, this will
+    // become available. As of this writing (25/03/19) it is not yet.
+    false
+}
diff --git a/src/tools/clippy/clippy_lints/src/transmute/utils.rs b/src/tools/clippy/clippy_lints/src/transmute/utils.rs
index 74927570b40e..8e90d20265ce 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/utils.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/utils.rs
@@ -2,7 +2,7 @@ use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{cast::CastKind, Ty};
 use rustc_span::DUMMY_SP;
-use rustc_typeck::check::{cast::CastCheck, FnCtxt, Inherited};
+use rustc_typeck::check::{cast::{self, CastCheckResult}, FnCtxt, Inherited};
 
 // check if the component types of the transmuted collection and the result have different ABI,
 // size or alignment
@@ -42,7 +42,7 @@ pub(super) fn can_be_expressed_as_pointer_cast<'tcx>(
 /// messages. This function will panic if that occurs.
 fn check_cast<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) -> Option<CastKind> {
     let hir_id = e.hir_id;
-    let local_def_id = hir_id.owner;
+    let local_def_id = hir_id.owner.def_id;
 
     Inherited::build(cx.tcx, local_def_id).enter(|inherited| {
         let fn_ctxt = FnCtxt::new(&inherited, cx.param_env, hir_id);
@@ -53,7 +53,7 @@ fn check_cast<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>
             "Newly created FnCtxt contained errors"
         );
 
-        if let Ok(check) = CastCheck::new(
+        if let CastCheckResult::Deferred(check) = cast::check_cast(
             &fn_ctxt, e, from_ty, to_ty,
             // We won't show any error to the user, so we don't care what the span is here.
             DUMMY_SP, DUMMY_SP,
diff --git a/src/tools/clippy/clippy_lints/src/transmuting_null.rs b/src/tools/clippy/clippy_lints/src/transmuting_null.rs
deleted file mode 100644
index 7939dfedc3a2..000000000000
--- a/src/tools/clippy/clippy_lints/src/transmuting_null.rs
+++ /dev/null
@@ -1,89 +0,0 @@
-use clippy_utils::consts::{constant_context, Constant};
-use clippy_utils::diagnostics::span_lint;
-use clippy_utils::is_expr_diagnostic_item;
-use if_chain::if_chain;
-use rustc_ast::LitKind;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::symbol::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for transmute calls which would receive a null pointer.
-    ///
-    /// ### Why is this bad?
-    /// Transmuting a null pointer is undefined behavior.
-    ///
-    /// ### Known problems
-    /// Not all cases can be detected at the moment of this writing.
-    /// For example, variables which hold a null pointer and are then fed to a `transmute`
-    /// call, aren't detectable yet.
-    ///
-    /// ### Example
-    /// ```rust
-    /// let null_ref: &u64 = unsafe { std::mem::transmute(0 as *const u64) };
-    /// ```
-    #[clippy::version = "1.35.0"]
-    pub TRANSMUTING_NULL,
-    correctness,
-    "transmutes from a null pointer to a reference, which is undefined behavior"
-}
-
-declare_lint_pass!(TransmutingNull => [TRANSMUTING_NULL]);
-
-const LINT_MSG: &str = "transmuting a known null pointer into a reference";
-
-impl<'tcx> LateLintPass<'tcx> for TransmutingNull {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if in_external_macro(cx.sess(), expr.span) {
-            return;
-        }
-
-        if_chain! {
-            if let ExprKind::Call(func, [arg]) = expr.kind;
-            if is_expr_diagnostic_item(cx, func, sym::transmute);
-
-            then {
-                // Catching transmute over constants that resolve to `null`.
-                let mut const_eval_context = constant_context(cx, cx.typeck_results());
-                if_chain! {
-                    if let ExprKind::Path(ref _qpath) = arg.kind;
-                    if let Some(Constant::RawPtr(x)) = const_eval_context.expr(arg);
-                    if x == 0;
-                    then {
-                        span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG)
-                    }
-                }
-
-                // Catching:
-                // `std::mem::transmute(0 as *const i32)`
-                if_chain! {
-                    if let ExprKind::Cast(inner_expr, _cast_ty) = arg.kind;
-                    if let ExprKind::Lit(ref lit) = inner_expr.kind;
-                    if let LitKind::Int(0, _) = lit.node;
-                    then {
-                        span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG)
-                    }
-                }
-
-                // Catching:
-                // `std::mem::transmute(std::ptr::null::<i32>())`
-                if_chain! {
-                    if let ExprKind::Call(func1, []) = arg.kind;
-                    if is_expr_diagnostic_item(cx, func1, sym::ptr_null);
-                    then {
-                        span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG)
-                    }
-                }
-
-                // FIXME:
-                // Also catch transmutations of variables which are known nulls.
-                // To do this, MIR const propagation seems to be the better tool.
-                // Whenever MIR const prop routines are more developed, this will
-                // become available. As of this writing (25/03/19) it is not yet.
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs b/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs
index 94945b2e1a9e..1268c23206a6 100644
--- a/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs
+++ b/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs
@@ -104,7 +104,7 @@ fn get_bounds_if_impl_trait<'tcx>(cx: &LateContext<'tcx>, qpath: &QPath<'_>, id:
         if let Some(Node::GenericParam(generic_param)) = cx.tcx.hir().get_if_local(did);
         if let GenericParamKind::Type { synthetic, .. } = generic_param.kind;
         if synthetic;
-        if let Some(generics) = cx.tcx.hir().get_generics(id.owner);
+        if let Some(generics) = cx.tcx.hir().get_generics(id.owner.def_id);
         if let Some(pred) = generics.bounds_for_param(did.expect_local()).next();
         then {
             Some(pred.bounds)
diff --git a/src/tools/clippy/clippy_lints/src/types/mod.rs b/src/tools/clippy/clippy_lints/src/types/mod.rs
index 353a6f6b899e..aca55817c525 100644
--- a/src/tools/clippy/clippy_lints/src/types/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/types/mod.rs
@@ -313,7 +313,7 @@ impl_lint_pass!(Types => [BOX_COLLECTION, VEC_BOX, OPTION_OPTION, LINKEDLIST, BO
 impl<'tcx> LateLintPass<'tcx> for Types {
     fn check_fn(&mut self, cx: &LateContext<'_>, _: FnKind<'_>, decl: &FnDecl<'_>, _: &Body<'_>, _: Span, id: HirId) {
         let is_in_trait_impl =
-            if let Some(hir::Node::Item(item)) = cx.tcx.hir().find_by_def_id(cx.tcx.hir().get_parent_item(id)) {
+            if let Some(hir::Node::Item(item)) = cx.tcx.hir().find_by_def_id(cx.tcx.hir().get_parent_item(id).def_id) {
                 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
             } else {
                 false
@@ -333,7 +333,7 @@ impl<'tcx> LateLintPass<'tcx> for Types {
     }
 
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
-        let is_exported = cx.access_levels.is_exported(item.def_id);
+        let is_exported = cx.access_levels.is_exported(item.def_id.def_id);
 
         match item.kind {
             ItemKind::Static(ty, _, _) | ItemKind::Const(ty, _) => self.check_ty(
@@ -353,7 +353,7 @@ impl<'tcx> LateLintPass<'tcx> for Types {
         match item.kind {
             ImplItemKind::Const(ty, _) => {
                 let is_in_trait_impl = if let Some(hir::Node::Item(item)) =
-                    cx.tcx.hir().find_by_def_id(cx.tcx.hir().get_parent_item(item.hir_id()))
+                    cx.tcx.hir().find_by_def_id(cx.tcx.hir().get_parent_item(item.hir_id()).def_id)
                 {
                     matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
                 } else {
@@ -390,7 +390,7 @@ impl<'tcx> LateLintPass<'tcx> for Types {
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &TraitItem<'_>) {
-        let is_exported = cx.access_levels.is_exported(item.def_id);
+        let is_exported = cx.access_levels.is_exported(item.def_id.def_id);
 
         let context = CheckTyContext {
             is_exported,
diff --git a/src/tools/clippy/clippy_lints/src/unicode.rs b/src/tools/clippy/clippy_lints/src/unicode.rs
index cc64d17be055..8980283e5c82 100644
--- a/src/tools/clippy/clippy_lints/src/unicode.rs
+++ b/src/tools/clippy/clippy_lints/src/unicode.rs
@@ -1,5 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::is_lint_allowed;
+use clippy_utils::macros::span_is_local;
 use clippy_utils::source::snippet;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
@@ -98,6 +99,10 @@ fn escape<T: Iterator<Item = char>>(s: T) -> String {
 }
 
 fn check_str(cx: &LateContext<'_>, span: Span, id: HirId) {
+    if !span_is_local(span) {
+        return;
+    }
+
     let string = snippet(cx, span, "");
     if string.chars().any(|c| ['\u{200B}', '\u{ad}', '\u{2060}'].contains(&c)) {
         span_lint_and_sugg(
@@ -113,6 +118,7 @@ fn check_str(cx: &LateContext<'_>, span: Span, id: HirId) {
             Applicability::MachineApplicable,
         );
     }
+
     if string.chars().any(|c| c as u32 > 0x7F) {
         span_lint_and_sugg(
             cx,
@@ -128,6 +134,7 @@ fn check_str(cx: &LateContext<'_>, span: Span, id: HirId) {
             Applicability::MachineApplicable,
         );
     }
+
     if is_lint_allowed(cx, NON_ASCII_LITERAL, id) && string.chars().zip(string.nfc()).any(|(a, b)| a != b) {
         span_lint_and_sugg(
             cx,
diff --git a/src/tools/clippy/clippy_lints/src/uninit_vec.rs b/src/tools/clippy/clippy_lints/src/uninit_vec.rs
index 9f4c5555f11b..3f99bd3f3156 100644
--- a/src/tools/clippy/clippy_lints/src/uninit_vec.rs
+++ b/src/tools/clippy/clippy_lints/src/uninit_vec.rs
@@ -45,7 +45,7 @@ declare_clippy_lint! {
     ///    let mut vec: Vec<MaybeUninit<T>> = Vec::with_capacity(1000);
     ///    vec.set_len(1000);  // `MaybeUninit` can be uninitialized
     ///    ```
-    /// 3. If you are on nightly, `Vec::spare_capacity_mut()` is available:
+    /// 3. If you are on 1.60.0 or later, `Vec::spare_capacity_mut()` is available:
     ///    ```rust,ignore
     ///    let mut vec: Vec<u8> = Vec::with_capacity(1000);
     ///    let remaining = vec.spare_capacity_mut();  // `&mut [MaybeUninit<u8>]`
@@ -177,7 +177,7 @@ fn extract_init_or_reserve_target<'tcx>(cx: &LateContext<'tcx>, stmt: &'tcx Stmt
                     });
                 }
             },
-            ExprKind::MethodCall(path, [self_expr, _], _) if is_reserve(cx, path, self_expr) => {
+            ExprKind::MethodCall(path, self_expr, [_], _) if is_reserve(cx, path, self_expr) => {
                 return Some(TargetVec {
                     location: VecLocation::Expr(self_expr),
                     init_kind: None,
@@ -211,7 +211,7 @@ fn extract_set_len_self<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Opt
         }
     });
     match expr.kind {
-        ExprKind::MethodCall(path, [self_expr, _], _) => {
+        ExprKind::MethodCall(path, self_expr, [_], _) => {
             let self_type = cx.typeck_results().expr_ty(self_expr).peel_refs();
             if is_type_diagnostic_item(cx, self_type, sym::Vec) && path.ident.name.as_str() == "set_len" {
                 Some((self_expr, expr.span))
diff --git a/src/tools/clippy/clippy_lints/src/unit_hash.rs b/src/tools/clippy/clippy_lints/src/unit_hash.rs
deleted file mode 100644
index 88ca0cb20a12..000000000000
--- a/src/tools/clippy/clippy_lints/src/unit_hash.rs
+++ /dev/null
@@ -1,78 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::source::snippet;
-use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Detects `().hash(_)`.
-    ///
-    /// ### Why is this bad?
-    /// Hashing a unit value doesn't do anything as the implementation of `Hash` for `()` is a no-op.
-    ///
-    /// ### Example
-    /// ```rust
-    /// # use std::hash::Hash;
-    /// # use std::collections::hash_map::DefaultHasher;
-    /// # enum Foo { Empty, WithValue(u8) }
-    /// # use Foo::*;
-    /// # let mut state = DefaultHasher::new();
-    /// # let my_enum = Foo::Empty;
-    /// match my_enum {
-    /// 	Empty => ().hash(&mut state),
-    /// 	WithValue(x) => x.hash(&mut state),
-    /// }
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// # use std::hash::Hash;
-    /// # use std::collections::hash_map::DefaultHasher;
-    /// # enum Foo { Empty, WithValue(u8) }
-    /// # use Foo::*;
-    /// # let mut state = DefaultHasher::new();
-    /// # let my_enum = Foo::Empty;
-    /// match my_enum {
-    /// 	Empty => 0_u8.hash(&mut state),
-    /// 	WithValue(x) => x.hash(&mut state),
-    /// }
-    /// ```
-    #[clippy::version = "1.58.0"]
-    pub UNIT_HASH,
-    correctness,
-    "hashing a unit value, which does nothing"
-}
-declare_lint_pass!(UnitHash => [UNIT_HASH]);
-
-impl<'tcx> LateLintPass<'tcx> for UnitHash {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        if_chain! {
-            if let ExprKind::MethodCall(name_ident, args, _) = &expr.kind;
-            if name_ident.ident.name == sym::hash;
-            if let [recv, state_param] = args;
-            if cx.typeck_results().expr_ty(recv).is_unit();
-            then {
-                span_lint_and_then(
-                    cx,
-                    UNIT_HASH,
-                    expr.span,
-                    "this call to `hash` on the unit type will do nothing",
-                    |diag| {
-                        diag.span_suggestion(
-                            expr.span,
-                            "remove the call to `hash` or consider using",
-                            format!(
-                                "0_u8.hash({})",
-                                snippet(cx, state_param.span, ".."),
-                            ),
-                            Applicability::MaybeIncorrect,
-                        );
-                        diag.note("the implementation of `Hash` for `()` is a no-op");
-                    }
-                );
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs b/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
index b0fce91abeb7..c0a4f3fbacd6 100644
--- a/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
@@ -144,11 +144,12 @@ fn check_arg<'tcx>(cx: &LateContext<'tcx>, arg: &'tcx Expr<'tcx>) -> Option<(Spa
 
 impl<'tcx> LateLintPass<'tcx> for UnitReturnExpectingOrd {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        if let ExprKind::MethodCall(_, args, _) = expr.kind {
+        if let ExprKind::MethodCall(_, receiver, args, _) = expr.kind {
             let arg_indices = get_args_to_check(cx, expr);
+            let args = std::iter::once(receiver).chain(args.iter()).collect::<Vec<_>>();
             for (i, trait_name) in arg_indices {
                 if i < args.len() {
-                    match check_arg(cx, &args[i]) {
+                    match check_arg(cx, args[i]) {
                         Some((span, None)) => {
                             span_lint(
                                 cx,
diff --git a/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs b/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs
index aec028d5c482..ce9ebad8c89a 100644
--- a/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_types/let_unit_value.rs
@@ -19,10 +19,12 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, local: &'tcx Local<'_>) {
         && cx.typeck_results().pat_ty(local.pat).is_unit()
     {
         if (local.ty.map_or(false, |ty| !matches!(ty.kind, TyKind::Infer))
-            || matches!(local.pat.kind, PatKind::Tuple([], None)))
+            || matches!(local.pat.kind, PatKind::Tuple([], ddpos) if ddpos.as_opt_usize().is_none()))
             && expr_needs_inferred_result(cx, init)
         {
-            if !matches!(local.pat.kind, PatKind::Wild | PatKind::Tuple([], None)) {
+            if !matches!(local.pat.kind, PatKind::Wild)
+               && !matches!(local.pat.kind, PatKind::Tuple([], ddpos) if ddpos.as_opt_usize().is_none())
+            {
                 span_lint_and_then(
                     cx,
                     LET_UNIT_VALUE,
@@ -128,7 +130,7 @@ fn needs_inferred_result_ty(
     locals_to_check: &mut Vec<HirId>,
     seen_locals: &mut HirIdSet,
 ) -> bool {
-    let (id, args) = match e.kind {
+    let (id, receiver, args) = match e.kind {
         ExprKind::Call(
             Expr {
                 kind: ExprKind::Path(ref path),
@@ -137,11 +139,11 @@ fn needs_inferred_result_ty(
             },
             args,
         ) => match cx.qpath_res(path, *hir_id) {
-            Res::Def(DefKind::AssocFn | DefKind::Fn, id) => (id, args),
+            Res::Def(DefKind::AssocFn | DefKind::Fn, id) => (id, None, args),
             _ => return false,
         },
-        ExprKind::MethodCall(_, args, _) => match cx.typeck_results().type_dependent_def_id(e.hir_id) {
-            Some(id) => (id, args),
+        ExprKind::MethodCall(_, receiver, args, _) => match cx.typeck_results().type_dependent_def_id(e.hir_id) {
+            Some(id) => (id, Some(receiver), args),
             None => return false,
         },
         ExprKind::Path(QPath::Resolved(None, path)) => {
@@ -156,6 +158,11 @@ fn needs_inferred_result_ty(
     };
     let sig = cx.tcx.fn_sig(id).skip_binder();
     if let ty::Param(output_ty) = *sig.output().kind() {
+        let args: Vec<&Expr<'_>> = if let Some(receiver) = receiver {
+            std::iter::once(receiver).chain(args.iter()).collect()
+        } else {
+            args.iter().collect()
+        };
         sig.inputs().iter().zip(args).all(|(&ty, arg)| {
             !ty.is_param(output_ty.index) || each_value_source_needs_inference(cx, arg, locals_to_check, seen_locals)
         })
diff --git a/src/tools/clippy/clippy_lints/src/unit_types/unit_arg.rs b/src/tools/clippy/clippy_lints/src/unit_types/unit_arg.rs
index 16da2f11b81a..a6f777abc6e9 100644
--- a/src/tools/clippy/clippy_lints/src/unit_types/unit_arg.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_types/unit_arg.rs
@@ -30,26 +30,27 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         }
     }
 
-    match expr.kind {
-        ExprKind::Call(_, args) | ExprKind::MethodCall(_, args, _) => {
-            let args_to_recover = args
-                .iter()
-                .filter(|arg| {
-                    if cx.typeck_results().expr_ty(arg).is_unit() && !utils::is_unit_literal(arg) {
-                        !matches!(
-                            &arg.kind,
-                            ExprKind::Match(.., MatchSource::TryDesugar) | ExprKind::Path(..)
-                        )
-                    } else {
-                        false
-                    }
-                })
-                .collect::<Vec<_>>();
-            if !args_to_recover.is_empty() && !is_from_proc_macro(cx, expr) {
-                lint_unit_args(cx, expr, &args_to_recover);
+    let args: Vec<_> = match expr.kind {
+        ExprKind::Call(_, args) => args.iter().collect(),
+        ExprKind::MethodCall(_, receiver, args, _) => std::iter::once(receiver).chain(args.iter()).collect(),
+        _ => return,
+    };
+
+    let args_to_recover = args
+        .into_iter()
+        .filter(|arg| {
+            if cx.typeck_results().expr_ty(arg).is_unit() && !utils::is_unit_literal(arg) {
+                !matches!(
+                    &arg.kind,
+                    ExprKind::Match(.., MatchSource::TryDesugar) | ExprKind::Path(..)
+                )
+            } else {
+                false
             }
-        },
-        _ => (),
+        })
+        .collect::<Vec<_>>();
+    if !args_to_recover.is_empty() && !is_from_proc_macro(cx, expr) {
+        lint_unit_args(cx, expr, args_to_recover.as_slice());
     }
 }
 
diff --git a/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs b/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs
index f4f5a4336a39..2c40827db0e7 100644
--- a/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs
+++ b/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs
@@ -115,7 +115,7 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
 
         // Check if all return expression respect the following condition and collect them.
         let mut suggs = Vec::new();
-        let can_sugg = find_all_ret_expressions(cx, &body.value, |ret_expr| {
+        let can_sugg = find_all_ret_expressions(cx, body.value, |ret_expr| {
             if_chain! {
                 if !ret_expr.span.from_expansion();
                 // Check if a function call.
@@ -130,7 +130,7 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
                         (
                             ret_expr.span,
                             if inner_type.is_unit() {
-                                "".to_string()
+                                String::new()
                             } else {
                                 snippet(cx, arg.span.source_callsite(), "..").to_string()
                             }
diff --git a/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs b/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
index 04e2f301bfd8..fb73c386640b 100644
--- a/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
+++ b/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
@@ -137,12 +137,12 @@ fn insert_necessary_parens(pat: &mut P<Pat>) {
     struct Visitor;
     impl MutVisitor for Visitor {
         fn visit_pat(&mut self, pat: &mut P<Pat>) {
-            use ast::{BindingMode::*, Mutability::*};
+            use ast::BindingAnnotation;
             noop_visit_pat(pat, self);
             let target = match &mut pat.kind {
                 // `i @ a | b`, `box a | b`, and `& mut? a | b`.
                 Ident(.., Some(p)) | Box(p) | Ref(p, _) if matches!(&p.kind, Or(ps) if ps.len() > 1) => p,
-                Ref(p, Not) if matches!(p.kind, Ident(ByValue(Mut), ..)) => p, // `&(mut x)`
+                Ref(p, Mutability::Not) if matches!(p.kind, Ident(BindingAnnotation::MUT, ..)) => p, // `&(mut x)`
                 _ => return,
             };
             target.kind = Paren(P(take_pat(target)));
diff --git a/src/tools/clippy/clippy_lints/src/unused_async.rs b/src/tools/clippy/clippy_lints/src/unused_async.rs
index a832dfcccaf3..bf487c7ca20c 100644
--- a/src/tools/clippy/clippy_lints/src/unused_async.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_async.rs
@@ -70,7 +70,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedAsync {
     ) {
         if !span.from_expansion() && fn_kind.asyncness() == IsAsync::Async {
             let mut visitor = AsyncFnVisitor { cx, found_await: false };
-            walk_fn(&mut visitor, fn_kind, fn_decl, body.id(), span, hir_id);
+            walk_fn(&mut visitor, fn_kind, fn_decl, body.id(), hir_id);
             if !visitor.found_await {
                 span_lint_and_help(
                     cx,
diff --git a/src/tools/clippy/clippy_lints/src/unused_io_amount.rs b/src/tools/clippy/clippy_lints/src/unused_io_amount.rs
index 323cf83ffcff..b38d71784fcf 100644
--- a/src/tools/clippy/clippy_lints/src/unused_io_amount.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_io_amount.rs
@@ -64,7 +64,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedIoAmount {
                     check_map_error(cx, res, expr);
                 }
             },
-            hir::ExprKind::MethodCall(path, [ref arg_0, ..], _) => match path.ident.as_str() {
+            hir::ExprKind::MethodCall(path, arg_0, ..) => match path.ident.as_str() {
                 "expect" | "unwrap" | "unwrap_or" | "unwrap_or_else" => {
                     check_map_error(cx, arg_0, expr);
                 },
@@ -94,9 +94,9 @@ fn try_remove_await<'a>(expr: &'a hir::Expr<'a>) -> Option<&hir::Expr<'a>> {
 
 fn check_map_error(cx: &LateContext<'_>, call: &hir::Expr<'_>, expr: &hir::Expr<'_>) {
     let mut call = call;
-    while let hir::ExprKind::MethodCall(path, args, _) = call.kind {
+    while let hir::ExprKind::MethodCall(path, receiver, ..) = call.kind {
         if matches!(path.ident.as_str(), "or" | "or_else" | "ok") {
-            call = &args[0];
+            call = receiver;
         } else {
             break;
         }
@@ -110,7 +110,7 @@ fn check_map_error(cx: &LateContext<'_>, call: &hir::Expr<'_>, expr: &hir::Expr<
 }
 
 fn check_method_call(cx: &LateContext<'_>, call: &hir::Expr<'_>, expr: &hir::Expr<'_>, is_await: bool) {
-    if let hir::ExprKind::MethodCall(path, _, _) = call.kind {
+    if let hir::ExprKind::MethodCall(path, ..) = call.kind {
         let symbol = path.ident.as_str();
         let read_trait = if is_await {
             match_trait_method(cx, call, &paths::FUTURES_IO_ASYNCREADEXT)
diff --git a/src/tools/clippy/clippy_lints/src/unused_peekable.rs b/src/tools/clippy/clippy_lints/src/unused_peekable.rs
new file mode 100644
index 000000000000..f1cebf0f9923
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/unused_peekable.rs
@@ -0,0 +1,232 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::{match_type, peel_mid_ty_refs_is_mutable};
+use clippy_utils::{fn_def_id, is_trait_method, path_to_local_id, paths, peel_ref_operators};
+use rustc_ast::Mutability;
+use rustc_hir::intravisit::{walk_expr, Visitor};
+use rustc_hir::lang_items::LangItem;
+use rustc_hir::{Block, Expr, ExprKind, HirId, Local, Node, PatKind, PathSegment, StmtKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::hir::nested_filter::OnlyBodies;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for the creation of a `peekable` iterator that is never `.peek()`ed
+    ///
+    /// ### Why is this bad?
+    /// Creating a peekable iterator without using any of its methods is likely a mistake,
+    /// or just a leftover after a refactor.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let collection = vec![1, 2, 3];
+    /// let iter = collection.iter().peekable();
+    ///
+    /// for item in iter {
+    ///     // ...
+    /// }
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust
+    /// let collection = vec![1, 2, 3];
+    /// let iter = collection.iter();
+    ///
+    /// for item in iter {
+    ///     // ...
+    /// }
+    /// ```
+    #[clippy::version = "1.64.0"]
+    pub UNUSED_PEEKABLE,
+    nursery,
+    "creating a peekable iterator without using any of its methods"
+}
+
+declare_lint_pass!(UnusedPeekable => [UNUSED_PEEKABLE]);
+
+impl<'tcx> LateLintPass<'tcx> for UnusedPeekable {
+    fn check_block(&mut self, cx: &LateContext<'tcx>, block: &Block<'tcx>) {
+        // Don't lint `Peekable`s returned from a block
+        if let Some(expr) = block.expr
+            && let Some(ty) = cx.typeck_results().expr_ty_opt(peel_ref_operators(cx, expr))
+            && match_type(cx, ty, &paths::PEEKABLE)
+        {
+            return;
+        }
+
+        for (idx, stmt) in block.stmts.iter().enumerate() {
+            if !stmt.span.from_expansion()
+                && let StmtKind::Local(local) = stmt.kind
+                && let PatKind::Binding(_, binding, ident, _) = local.pat.kind
+                && let Some(init) = local.init
+                && !init.span.from_expansion()
+                && let Some(ty) = cx.typeck_results().expr_ty_opt(init)
+                && let (ty, _, Mutability::Mut) = peel_mid_ty_refs_is_mutable(ty)
+                && match_type(cx, ty, &paths::PEEKABLE)
+            {
+                let mut vis = PeekableVisitor::new(cx, binding);
+
+                if idx + 1 == block.stmts.len() && block.expr.is_none() {
+                    return;
+                }
+
+                for stmt in &block.stmts[idx..] {
+                    vis.visit_stmt(stmt);
+                }
+
+                if let Some(expr) = block.expr {
+                    vis.visit_expr(expr);
+                }
+
+                if !vis.found_peek_call {
+                    span_lint_and_help(
+                        cx,
+                        UNUSED_PEEKABLE,
+                        ident.span,
+                        "`peek` never called on `Peekable` iterator",
+                        None,
+                        "consider removing the call to `peekable`"
+                   );
+                }
+            }
+        }
+    }
+}
+
+struct PeekableVisitor<'a, 'tcx> {
+    cx: &'a LateContext<'tcx>,
+    expected_hir_id: HirId,
+    found_peek_call: bool,
+}
+
+impl<'a, 'tcx> PeekableVisitor<'a, 'tcx> {
+    fn new(cx: &'a LateContext<'tcx>, expected_hir_id: HirId) -> Self {
+        Self {
+            cx,
+            expected_hir_id,
+            found_peek_call: false,
+        }
+    }
+}
+
+impl<'tcx> Visitor<'tcx> for PeekableVisitor<'_, 'tcx> {
+    type NestedFilter = OnlyBodies;
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        self.cx.tcx.hir()
+    }
+
+    fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
+        if self.found_peek_call {
+            return;
+        }
+
+        if path_to_local_id(ex, self.expected_hir_id) {
+            for (_, node) in self.cx.tcx.hir().parent_iter(ex.hir_id) {
+                match node {
+                    Node::Expr(expr) => {
+                        match expr.kind {
+                            // some_function(peekable)
+                            //
+                            // If the Peekable is passed to a function, stop
+                            ExprKind::Call(_, args) => {
+                                if let Some(func_did) = fn_def_id(self.cx, expr)
+                                    && let Ok(into_iter_did) = self
+                                        .cx
+                                        .tcx
+                                        .lang_items()
+                                        .require(LangItem::IntoIterIntoIter)
+                                    && func_did == into_iter_did
+                                {
+                                    // Probably a for loop desugar, stop searching
+                                    return;
+                                }
+
+                                if args.iter().any(|arg| arg_is_mut_peekable(self.cx, arg)) {
+                                    self.found_peek_call = true;
+                                }
+
+                                return;
+                            },
+                            // Catch anything taking a Peekable mutably
+                            ExprKind::MethodCall(
+                                PathSegment {
+                                    ident: method_name_ident,
+                                    ..
+                                },
+                                self_arg,
+                                remaining_args,
+                                _,
+                            ) => {
+                                let method_name = method_name_ident.name.as_str();
+
+                                // `Peekable` methods
+                                if matches!(method_name, "peek" | "peek_mut" | "next_if" | "next_if_eq")
+                                    && arg_is_mut_peekable(self.cx, self_arg)
+                                {
+                                    self.found_peek_call = true;
+                                    return;
+                                }
+
+                                // foo.some_method() excluding Iterator methods
+                                if remaining_args.iter().any(|arg| arg_is_mut_peekable(self.cx, arg))
+                                    && !is_trait_method(self.cx, expr, sym::Iterator)
+                                {
+                                    self.found_peek_call = true;
+                                    return;
+                                }
+
+                                // foo.by_ref(), keep checking for `peek`
+                                if method_name == "by_ref" {
+                                    continue;
+                                }
+
+                                return;
+                            },
+                            ExprKind::AddrOf(_, Mutability::Mut, _) | ExprKind::Unary(..) | ExprKind::DropTemps(_) => {
+                            },
+                            ExprKind::AddrOf(_, Mutability::Not, _) => return,
+                            _ => {
+                                self.found_peek_call = true;
+                                return;
+                            },
+                        }
+                    },
+                    Node::Local(Local { init: Some(init), .. }) => {
+                        if arg_is_mut_peekable(self.cx, init) {
+                            self.found_peek_call = true;
+                        }
+
+                        return;
+                    },
+                    Node::Stmt(stmt) => {
+                        match stmt.kind {
+                            StmtKind::Local(_) | StmtKind::Item(_) => self.found_peek_call = true,
+                            StmtKind::Expr(_) | StmtKind::Semi(_) => {},
+                        }
+
+                        return;
+                    },
+                    Node::Block(_) | Node::ExprField(_) => {},
+                    _ => {
+                        return;
+                    },
+                }
+            }
+        }
+
+        walk_expr(self, ex);
+    }
+}
+
+fn arg_is_mut_peekable(cx: &LateContext<'_>, arg: &Expr<'_>) -> bool {
+    if let Some(ty) = cx.typeck_results().expr_ty_opt(arg)
+        && let (ty, _, Mutability::Mut) = peel_mid_ty_refs_is_mutable(ty)
+        && match_type(cx, ty, &paths::PEEKABLE)
+    {
+        true
+    } else {
+        false
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/unused_rounding.rs b/src/tools/clippy/clippy_lints/src/unused_rounding.rs
index e1ec357838db..b8a5d4ea8c9f 100644
--- a/src/tools/clippy/clippy_lints/src/unused_rounding.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_rounding.rs
@@ -22,7 +22,7 @@ declare_clippy_lint! {
     /// ```rust
     /// let x = 1f32;
     /// ```
-    #[clippy::version = "1.62.0"]
+    #[clippy::version = "1.63.0"]
     pub UNUSED_ROUNDING,
     nursery,
     "Uselessly rounding a whole number floating-point literal"
diff --git a/src/tools/clippy/clippy_lints/src/unused_self.rs b/src/tools/clippy/clippy_lints/src/unused_self.rs
index 51c65d898cf5..713fe06bad43 100644
--- a/src/tools/clippy/clippy_lints/src/unused_self.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_self.rs
@@ -54,14 +54,14 @@ impl<'tcx> LateLintPass<'tcx> for UnusedSelf {
         if impl_item.span.from_expansion() {
             return;
         }
-        let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+        let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id()).def_id;
         let parent_item = cx.tcx.hir().expect_item(parent);
         let assoc_item = cx.tcx.associated_item(impl_item.def_id);
         if_chain! {
             if let ItemKind::Impl(Impl { of_trait: None, .. }) = parent_item.kind;
             if assoc_item.fn_has_self_parameter;
             if let ImplItemKind::Fn(.., body_id) = &impl_item.kind;
-            if !cx.access_levels.is_exported(impl_item.def_id) || !self.avoid_breaking_exported_api;
+            if !cx.access_levels.is_exported(impl_item.def_id.def_id) || !self.avoid_breaking_exported_api;
             let body = cx.tcx.hir().body(*body_id);
             if let [self_param, ..] = body.params;
             if !is_local_used(cx, body, self_param.pat.hir_id);
diff --git a/src/tools/clippy/clippy_lints/src/unwrap.rs b/src/tools/clippy/clippy_lints/src/unwrap.rs
index d3f9e5abfd73..3ef265580797 100644
--- a/src/tools/clippy/clippy_lints/src/unwrap.rs
+++ b/src/tools/clippy/clippy_lints/src/unwrap.rs
@@ -154,13 +154,13 @@ fn collect_unwrap_info<'tcx>(
         return collect_unwrap_info(cx, if_expr, expr, branch, !invert, false);
     } else {
         if_chain! {
-            if let ExprKind::MethodCall(method_name, args, _) = &expr.kind;
-            if let Some(local_id) = path_to_local(&args[0]);
-            let ty = cx.typeck_results().expr_ty(&args[0]);
+            if let ExprKind::MethodCall(method_name, receiver, args, _) = &expr.kind;
+            if let Some(local_id) = path_to_local(receiver);
+            let ty = cx.typeck_results().expr_ty(receiver);
             let name = method_name.ident.as_str();
             if is_relevant_option_call(cx, ty, name) || is_relevant_result_call(cx, ty, name);
             then {
-                assert!(args.len() == 1);
+                assert!(args.is_empty());
                 let unwrappable = match name {
                     "is_some" | "is_ok" => true,
                     "is_err" | "is_none" => false,
@@ -231,7 +231,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnwrappableVariablesVisitor<'a, 'tcx> {
         } else {
             // find `unwrap[_err]()` calls:
             if_chain! {
-                if let ExprKind::MethodCall(method_name, [self_arg, ..], _) = expr.kind;
+                if let ExprKind::MethodCall(method_name, self_arg, ..) = expr.kind;
                 if let Some(id) = path_to_local(self_arg);
                 if [sym::unwrap, sym::expect, sym!(unwrap_err)].contains(&method_name.ident.name);
                 let call_to_unwrap = [sym::unwrap, sym::expect].contains(&method_name.ident.name);
@@ -326,6 +326,6 @@ impl<'tcx> LateLintPass<'tcx> for Unwrap {
             unwrappables: Vec::new(),
         };
 
-        walk_fn(&mut v, kind, decl, body.id(), span, fn_id);
+        walk_fn(&mut v, kind, decl, body.id(), fn_id);
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/unwrap_in_result.rs b/src/tools/clippy/clippy_lints/src/unwrap_in_result.rs
index b32be238cd55..baa53ba664f6 100644
--- a/src/tools/clippy/clippy_lints/src/unwrap_in_result.rs
+++ b/src/tools/clippy/clippy_lints/src/unwrap_in_result.rs
@@ -83,7 +83,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindExpectUnwrap<'a, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
         // check for `expect`
         if let Some(arglists) = method_chain_args(expr, &["expect"]) {
-            let receiver_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
+            let receiver_ty = self.typeck_results.expr_ty(arglists[0].0).peel_refs();
             if is_type_diagnostic_item(self.lcx, receiver_ty, sym::Option)
                 || is_type_diagnostic_item(self.lcx, receiver_ty, sym::Result)
             {
@@ -93,7 +93,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindExpectUnwrap<'a, 'tcx> {
 
         // check for `unwrap`
         if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
-            let receiver_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
+            let receiver_ty = self.typeck_results.expr_ty(arglists[0].0).peel_refs();
             if is_type_diagnostic_item(self.lcx, receiver_ty, sym::Option)
                 || is_type_diagnostic_item(self.lcx, receiver_ty, sym::Result)
             {
@@ -111,10 +111,10 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_item: &'tc
         let body = cx.tcx.hir().body(body_id);
         let mut fpu = FindExpectUnwrap {
             lcx: cx,
-            typeck_results: cx.tcx.typeck(impl_item.def_id),
+            typeck_results: cx.tcx.typeck(impl_item.def_id.def_id),
             result: Vec::new(),
         };
-        fpu.visit_expr(&body.value);
+        fpu.visit_expr(body.value);
 
         // if we've found one, lint
         if !fpu.result.is_empty() {
diff --git a/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs b/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs
index 02bf09ed5068..2c71f35d490c 100644
--- a/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs
+++ b/src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs
@@ -105,7 +105,7 @@ impl LateLintPass<'_> for UpperCaseAcronyms {
     fn check_item(&mut self, cx: &LateContext<'_>, it: &Item<'_>) {
         // do not lint public items or in macros
         if in_external_macro(cx.sess(), it.span)
-            || (self.avoid_breaking_exported_api && cx.access_levels.is_exported(it.def_id))
+            || (self.avoid_breaking_exported_api && cx.access_levels.is_exported(it.def_id.def_id))
         {
             return;
         }
diff --git a/src/tools/clippy/clippy_lints/src/use_self.rs b/src/tools/clippy/clippy_lints/src/use_self.rs
index 486ea5e5ccfa..ce51cb693fc0 100644
--- a/src/tools/clippy/clippy_lints/src/use_self.rs
+++ b/src/tools/clippy/clippy_lints/src/use_self.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::ty::same_type_and_consts;
-use clippy_utils::{meets_msrv, msrvs};
+use clippy_utils::{is_from_proc_macro, meets_msrv, msrvs};
 use if_chain::if_chain;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
@@ -87,7 +87,7 @@ impl_lint_pass!(UseSelf => [USE_SELF]);
 const SEGMENTS_MSG: &str = "segments should be composed of at least 1 element";
 
 impl<'tcx> LateLintPass<'tcx> for UseSelf {
-    fn check_item(&mut self, _cx: &LateContext<'_>, item: &Item<'_>) {
+    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &Item<'tcx>) {
         if matches!(item.kind, ItemKind::OpaqueTy(_)) {
             // skip over `ItemKind::OpaqueTy` in order to lint `foo() -> impl <..>`
             return;
@@ -103,9 +103,10 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
             if parameters.as_ref().map_or(true, |params| {
                 !params.parenthesized && !params.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_)))
             });
+            if !is_from_proc_macro(cx, item); // expensive, should be last check
             then {
                 StackItem::Check {
-                    impl_id: item.def_id,
+                    impl_id: item.def_id.def_id,
                     in_body: 0,
                     types_to_skip: std::iter::once(self_ty.hir_id).collect(),
                 }
@@ -213,9 +214,6 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
                 hir_ty_to_ty(cx.tcx, hir_ty)
             };
             if same_type_and_consts(ty, cx.tcx.type_of(impl_id));
-            let hir = cx.tcx.hir();
-            // prevents false positive on `#[derive(serde::Deserialize)]`
-            if !hir.span(hir.get_parent_node(hir_ty.hir_id)).in_derive_expansion();
             then {
                 span_lint(cx, hir_ty.span);
             }
diff --git a/src/tools/clippy/clippy_lints/src/useless_conversion.rs b/src/tools/clippy/clippy_lints/src/useless_conversion.rs
index b6738e2891d3..f1b6463ad0f7 100644
--- a/src/tools/clippy/clippy_lints/src/useless_conversion.rs
+++ b/src/tools/clippy/clippy_lints/src/useless_conversion.rs
@@ -64,7 +64,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
                 }
             },
 
-            ExprKind::MethodCall(name, .., [recv, ..], _) => {
+            ExprKind::MethodCall(name, recv, ..) => {
                 if is_trait_method(cx, e, sym::Into) && name.ident.as_str() == "into" {
                     let a = cx.typeck_results().expr_ty(e);
                     let b = cx.typeck_results().expr_ty(recv);
diff --git a/src/tools/clippy/clippy_lints/src/utils/author.rs b/src/tools/clippy/clippy_lints/src/utils/author.rs
index 429c64ac1564..1df3135c962d 100644
--- a/src/tools/clippy/clippy_lints/src/utils/author.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/author.rs
@@ -6,7 +6,9 @@ use rustc_ast::ast::{LitFloatType, LitKind};
 use rustc_ast::LitIntType;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
-use rustc_hir::{ArrayLen, Closure, ExprKind, FnRetTy, HirId, Lit, PatKind, QPath, StmtKind, TyKind};
+use rustc_hir::{
+    ArrayLen, BindingAnnotation, Closure, ExprKind, FnRetTy, HirId, Lit, PatKind, QPath, StmtKind, TyKind,
+};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::{Ident, Symbol};
@@ -138,9 +140,9 @@ impl<'tcx> LateLintPass<'tcx> for Author {
 
 fn check_item(cx: &LateContext<'_>, hir_id: HirId) {
     let hir = cx.tcx.hir();
-    if let Some(body_id) = hir.maybe_body_owned_by(hir_id.expect_owner()) {
+    if let Some(body_id) = hir.maybe_body_owned_by(hir_id.expect_owner().def_id) {
         check_node(cx, hir_id, |v| {
-            v.expr(&v.bind("expr", &hir.body(body_id).value));
+            v.expr(&v.bind("expr", hir.body(body_id).value));
         });
     }
 }
@@ -402,10 +404,11 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 self.expr(func);
                 self.slice(args, |e| self.expr(e));
             },
-            ExprKind::MethodCall(method_name, args, _) => {
-                bind!(self, method_name, args);
-                kind!("MethodCall({method_name}, {args}, _)");
+            ExprKind::MethodCall(method_name, receiver, args, _) => {
+                bind!(self, method_name, receiver, args);
+                kind!("MethodCall({method_name}, {receiver}, {args}, _)");
                 self.ident(field!(method_name.ident));
+                self.expr(receiver);
                 self.slice(args, |e| self.expr(e));
             },
             ExprKind::Tup(elements) => {
@@ -595,7 +598,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     }
 
     fn body(&self, body_id: &Binding<hir::BodyId>) {
-        let expr = &self.cx.tcx.hir().body(body_id.value).value;
+        let expr = self.cx.tcx.hir().body(body_id.value).value;
         bind!(self, expr);
         out!("let {expr} = &cx.tcx.hir().body({body_id}).value;");
         self.expr(expr);
@@ -609,10 +612,16 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
 
         match pat.value.kind {
             PatKind::Wild => kind!("Wild"),
-            PatKind::Binding(anno, .., name, sub) => {
+            PatKind::Binding(ann, _, name, sub) => {
                 bind!(self, name);
                 opt_bind!(self, sub);
-                kind!("Binding(BindingAnnotation::{anno:?}, _, {name}, {sub})");
+                let ann = match ann {
+                    BindingAnnotation::NONE => "NONE",
+                    BindingAnnotation::REF => "REF",
+                    BindingAnnotation::MUT => "MUT",
+                    BindingAnnotation::REF_MUT => "REF_MUT",
+                };
+                kind!("Binding(BindingAnnotation::{ann}, _, {name}, {sub})");
                 self.ident(name);
                 sub.if_some(|p| self.pat(p));
             },
diff --git a/src/tools/clippy/clippy_lints/src/utils/conf.rs b/src/tools/clippy/clippy_lints/src/utils/conf.rs
index 3faae9ac0d2b..2be3fa99c811 100644
--- a/src/tools/clippy/clippy_lints/src/utils/conf.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/conf.rs
@@ -208,7 +208,7 @@ define_Conf! {
     /// Lint: Arithmetic.
     ///
     /// Suppress checking of the passed type names.
-    (arithmetic_allowed: rustc_data_structures::fx::FxHashSet<String> = <_>::default()),
+    (arithmetic_side_effects_allowed: rustc_data_structures::fx::FxHashSet<String> = <_>::default()),
     /// Lint: ENUM_VARIANT_NAMES, LARGE_TYPES_PASSED_BY_VALUE, TRIVIALLY_COPY_PASS_BY_REF, UNNECESSARY_WRAPS, UNUSED_SELF, UPPER_CASE_ACRONYMS, WRONG_SELF_CONVENTION, BOX_COLLECTION, REDUNDANT_ALLOCATION, RC_BUFFER, VEC_BOX, OPTION_OPTION, LINKEDLIST, RC_MUTEX.
     ///
     /// Suppress lints whenever the suggested change would cause breakage for other crates.
@@ -350,7 +350,7 @@ define_Conf! {
     /// Lint: DISALLOWED_SCRIPT_IDENTS.
     ///
     /// The list of unicode scripts allowed to be used in the scope.
-    (allowed_scripts: Vec<String> = ["Latin"].iter().map(ToString::to_string).collect()),
+    (allowed_scripts: Vec<String> = vec!["Latin".to_string()]),
     /// Lint: NON_SEND_FIELDS_IN_SEND_TY.
     ///
     /// Whether to apply the raw pointer heuristic to determine if a type is `Send`.
@@ -379,6 +379,10 @@ define_Conf! {
     ///
     /// Whether `dbg!` should be allowed in test functions
     (allow_dbg_in_tests: bool = false),
+    /// Lint: RESULT_LARGE_ERR
+    ///
+    /// The maximum size of the `Err`-variant in a `Result` returned from a function
+    (large_error_threshold: u64 = 128),
 }
 
 /// Search for the configuration file.
@@ -472,7 +476,7 @@ pub fn format_error(error: Box<dyn Error>) -> String {
 
             let mut msg = String::from(prefix);
             for row in 0..rows {
-                write!(msg, "\n").unwrap();
+                writeln!(msg).unwrap();
                 for (column, column_width) in column_widths.iter().copied().enumerate() {
                     let index = column * rows + row;
                     let field = fields.get(index).copied().unwrap_or_default();
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints.rs
index 5dcacd604be4..17d9a0418576 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints.rs
@@ -505,7 +505,7 @@ impl<'tcx> LateLintPass<'tcx> for LintWithoutLintPass {
                             .hir_id(),
                     ),
                 );
-                collector.visit_expr(&cx.tcx.hir().body(body_id).value);
+                collector.visit_expr(cx.tcx.hir().body(body_id).value);
             }
         }
     }
@@ -593,8 +593,8 @@ fn extract_clippy_version_value(cx: &LateContext<'_>, item: &'_ Item<'_>) -> Opt
     attrs.iter().find_map(|attr| {
         if_chain! {
             // Identify attribute
-            if let ast::AttrKind::Normal(ref attr_kind, _) = &attr.kind;
-            if let [tool_name, attr_name] = &attr_kind.path.segments[..];
+            if let ast::AttrKind::Normal(ref attr_kind) = &attr.kind;
+            if let [tool_name, attr_name] = &attr_kind.item.path.segments[..];
             if tool_name.ident.name == sym::clippy;
             if attr_name.ident.name == sym::version;
             if let Some(version) = attr.value_str();
@@ -653,7 +653,7 @@ impl<'tcx> LateLintPass<'tcx> for CompilerLintFunctions {
         }
 
         if_chain! {
-            if let ExprKind::MethodCall(path, [self_arg, ..], _) = &expr.kind;
+            if let ExprKind::MethodCall(path, self_arg, _, _) = &expr.kind;
             let fn_name = path.ident;
             if let Some(sugg) = self.map.get(fn_name.as_str());
             let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
@@ -685,9 +685,8 @@ impl<'tcx> LateLintPass<'tcx> for OuterExpnDataPass {
         let method_names: Vec<&str> = method_names.iter().map(Symbol::as_str).collect();
         if_chain! {
             if let ["expn_data", "outer_expn"] = method_names.as_slice();
-            let args = arg_lists[1];
-            if args.len() == 1;
-            let self_arg = &args[0];
+            let (self_arg, args)= arg_lists[1];
+            if args.is_empty();
             let self_ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
             if match_type(cx, self_ty, &paths::SYNTAX_CONTEXT);
             then {
@@ -734,30 +733,30 @@ impl<'tcx> LateLintPass<'tcx> for CollapsibleCalls {
             if and_then_args.len() == 5;
             if let ExprKind::Closure(&Closure { body, .. }) = &and_then_args[4].kind;
             let body = cx.tcx.hir().body(body);
-            let only_expr = peel_blocks_with_stmt(&body.value);
-            if let ExprKind::MethodCall(ps, span_call_args, _) = &only_expr.kind;
-            if let ExprKind::Path(..) = span_call_args[0].kind;
+            let only_expr = peel_blocks_with_stmt(body.value);
+            if let ExprKind::MethodCall(ps, recv, span_call_args, _) = &only_expr.kind;
+            if let ExprKind::Path(..) = recv.kind;
             then {
                 let and_then_snippets = get_and_then_snippets(cx, and_then_args);
                 let mut sle = SpanlessEq::new(cx).deny_side_effects();
                 match ps.ident.as_str() {
-                    "span_suggestion" if sle.eq_expr(&and_then_args[2], &span_call_args[1]) => {
+                    "span_suggestion" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
                         suggest_suggestion(cx, expr, &and_then_snippets, &span_suggestion_snippets(cx, span_call_args));
                     },
-                    "span_help" if sle.eq_expr(&and_then_args[2], &span_call_args[1]) => {
-                        let help_snippet = snippet(cx, span_call_args[2].span, r#""...""#);
+                    "span_help" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
+                        let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
                         suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), true);
                     },
-                    "span_note" if sle.eq_expr(&and_then_args[2], &span_call_args[1]) => {
-                        let note_snippet = snippet(cx, span_call_args[2].span, r#""...""#);
+                    "span_note" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
+                        let note_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
                         suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), true);
                     },
                     "help" => {
-                        let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
+                        let help_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
                         suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), false);
                     }
                     "note" => {
-                        let note_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
+                        let note_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
                         suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), false);
                     }
                     _  => (),
@@ -798,9 +797,9 @@ fn span_suggestion_snippets<'a, 'hir>(
     cx: &LateContext<'_>,
     span_call_args: &'hir [Expr<'hir>],
 ) -> SpanSuggestionSnippets<'a> {
-    let help_snippet = snippet(cx, span_call_args[2].span, r#""...""#);
-    let sugg_snippet = snippet(cx, span_call_args[3].span, "..");
-    let applicability_snippet = snippet(cx, span_call_args[4].span, "Applicability::MachineApplicable");
+    let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
+    let sugg_snippet = snippet(cx, span_call_args[2].span, "..");
+    let applicability_snippet = snippet(cx, span_call_args[3].span, "Applicability::MachineApplicable");
 
     SpanSuggestionSnippets {
         help: help_snippet,
@@ -954,7 +953,7 @@ fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Ve
                 if let Some(Node::Item(item)) = cx.tcx.hir().get_if_local(def_id) {
                     if let ItemKind::Const(.., body_id) | ItemKind::Static(.., body_id) = item.kind {
                         let body = cx.tcx.hir().body(body_id);
-                        return path_to_matched_type(cx, &body.value);
+                        return path_to_matched_type(cx, body.value);
                     }
                 }
             },
@@ -1046,7 +1045,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidPaths {
             if el_ty.is_str();
             let body = cx.tcx.hir().body(body_id);
             let typeck_results = cx.tcx.typeck_body(body_id);
-            if let Some(Constant::Vec(path)) = constant_simple(cx, typeck_results, &body.value);
+            if let Some(Constant::Vec(path)) = constant_simple(cx, typeck_results, body.value);
             let path: Vec<&str> = path.iter().map(|x| {
                     if let Constant::Str(s) = x {
                         s.as_str()
@@ -1177,7 +1176,7 @@ impl InterningDefinedSymbol {
         };
         if_chain! {
             // is a method call
-            if let ExprKind::MethodCall(_, [item], _) = call.kind;
+            if let ExprKind::MethodCall(_, item, [], _) = call.kind;
             if let Some(did) = cx.typeck_results().type_dependent_def_id(call.hir_id);
             let ty = cx.typeck_results().expr_ty(item);
             // ...on either an Ident or a Symbol
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
index 92cf42c7ad43..342f627e3827 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
@@ -797,7 +797,7 @@ fn get_lint_group_and_level_or_lint(
     let result = cx.lint_store.check_lint_name(
         lint_name,
         Some(sym::clippy),
-        &[Ident::with_dummy_span(sym::clippy)].into_iter().collect(),
+        &std::iter::once(Ident::with_dummy_span(sym::clippy)).collect(),
     );
     if let CheckLintNameResult::Tool(Ok(lint_lst)) = result {
         if let Some(group) = get_lint_group(cx, lint_lst[0]) {
@@ -1145,8 +1145,8 @@ impl<'a, 'hir> intravisit::Visitor<'hir> for IsMultiSpanScanner<'a, 'hir> {
                     self.add_single_span_suggestion();
                 }
             },
-            ExprKind::MethodCall(path, arg, _arg_span) => {
-                let (self_ty, _) = walk_ptrs_ty_depth(self.cx.typeck_results().expr_ty(&arg[0]));
+            ExprKind::MethodCall(path, recv, _, _arg_span) => {
+                let (self_ty, _) = walk_ptrs_ty_depth(self.cx.typeck_results().expr_ty(recv));
                 if match_type(self.cx, self_ty, &paths::DIAGNOSTIC_BUILDER) {
                     let called_method = path.ident.name.as_str().to_string();
                     for (method_name, is_multi_part) in &SUGGESTION_DIAGNOSTIC_BUILDER_METHODS {
diff --git a/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs b/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs
index 35db45e2b0c9..bd5be0c9d7ed 100644
--- a/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs
+++ b/src/tools/clippy/clippy_lints/src/vec_init_then_push.rs
@@ -86,7 +86,7 @@ impl VecPushSearcher {
                 },
                 ExprKind::Unary(UnOp::Deref, _) | ExprKind::Index(..) if !needs_mut => {
                     let mut last_place = parent;
-                    while let Some(parent) = get_parent_expr(cx, parent) {
+                    while let Some(parent) = get_parent_expr(cx, last_place) {
                         if matches!(parent.kind, ExprKind::Unary(UnOp::Deref, _) | ExprKind::Field(..))
                             || matches!(parent.kind, ExprKind::Index(e, _) if e.hir_id == last_place.hir_id)
                         {
@@ -100,7 +100,7 @@ impl VecPushSearcher {
                         || get_parent_expr(cx, last_place)
                             .map_or(false, |e| matches!(e.kind, ExprKind::AddrOf(_, Mutability::Mut, _)));
                 },
-                ExprKind::MethodCall(_, [recv, ..], _)
+                ExprKind::MethodCall(_, recv, ..)
                     if recv.hir_id == e.hir_id
                         && adjusted_mut == Mutability::Mut
                         && !adjusted_ty.peel_refs().is_slice() =>
@@ -157,7 +157,7 @@ impl<'tcx> LateLintPass<'tcx> for VecInitThenPush {
 
     fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx Local<'tcx>) {
         if let Some(init_expr) = local.init
-            && let PatKind::Binding(BindingAnnotation::Mutable, id, name, None) = local.pat.kind
+            && let PatKind::Binding(BindingAnnotation::MUT, id, name, None) = local.pat.kind
             && !in_external_macro(cx.sess(), local.span)
             && let Some(init) = get_vec_init_kind(cx, init_expr)
             && !matches!(init, VecInitKind::WithExprCapacity(_))
@@ -201,7 +201,7 @@ impl<'tcx> LateLintPass<'tcx> for VecInitThenPush {
     fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
         if let Some(searcher) = self.searcher.take() {
             if let StmtKind::Expr(expr) | StmtKind::Semi(expr) = stmt.kind
-                && let ExprKind::MethodCall(name, [self_arg, _], _) = expr.kind
+                && let ExprKind::MethodCall(name, self_arg, [_], _) = expr.kind
                 && path_to_local_id(self_arg, searcher.local_id)
                 && name.ident.as_str() == "push"
             {
diff --git a/src/tools/clippy/clippy_lints/src/vec_resize_to_zero.rs b/src/tools/clippy/clippy_lints/src/vec_resize_to_zero.rs
deleted file mode 100644
index 0fee3e812d28..000000000000
--- a/src/tools/clippy/clippy_lints/src/vec_resize_to_zero.rs
+++ /dev/null
@@ -1,64 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::{match_def_path, paths};
-use if_chain::if_chain;
-use rustc_ast::LitKind;
-use rustc_errors::Applicability;
-use rustc_hir as hir;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::source_map::Spanned;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Finds occurrences of `Vec::resize(0, an_int)`
-    ///
-    /// ### Why is this bad?
-    /// This is probably an argument inversion mistake.
-    ///
-    /// ### Example
-    /// ```rust
-    /// vec!(1, 2, 3, 4, 5).resize(0, 5)
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust
-    /// vec!(1, 2, 3, 4, 5).clear()
-    /// ```
-    #[clippy::version = "1.46.0"]
-    pub VEC_RESIZE_TO_ZERO,
-    correctness,
-    "emptying a vector with `resize(0, an_int)` instead of `clear()` is probably an argument inversion mistake"
-}
-
-declare_lint_pass!(VecResizeToZero => [VEC_RESIZE_TO_ZERO]);
-
-impl<'tcx> LateLintPass<'tcx> for VecResizeToZero {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if_chain! {
-            if let hir::ExprKind::MethodCall(path_segment, args, _) = expr.kind;
-            if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
-            if match_def_path(cx, method_def_id, &paths::VEC_RESIZE) && args.len() == 3;
-            if let ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = args[1].kind;
-            if let ExprKind::Lit(Spanned { node: LitKind::Int(..), .. }) = args[2].kind;
-            then {
-                let method_call_span = expr.span.with_lo(path_segment.ident.span.lo());
-                span_lint_and_then(
-                    cx,
-                    VEC_RESIZE_TO_ZERO,
-                    expr.span,
-                    "emptying a vector with `resize`",
-                    |db| {
-                        db.help("the arguments may be inverted...");
-                        db.span_suggestion(
-                            method_call_span,
-                            "...or you can empty the vector with",
-                            "clear()".to_string(),
-                            Applicability::MaybeIncorrect,
-                        );
-                    },
-                );
-            }
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/verbose_file_reads.rs b/src/tools/clippy/clippy_lints/src/verbose_file_reads.rs
deleted file mode 100644
index afd0077a6580..000000000000
--- a/src/tools/clippy/clippy_lints/src/verbose_file_reads.rs
+++ /dev/null
@@ -1,88 +0,0 @@
-use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::paths;
-use clippy_utils::ty::match_type;
-use if_chain::if_chain;
-use rustc_hir::{Expr, ExprKind, QPath};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for use of File::read_to_end and File::read_to_string.
-    ///
-    /// ### Why is this bad?
-    /// `fs::{read, read_to_string}` provide the same functionality when `buf` is empty with fewer imports and no intermediate values.
-    /// See also: [fs::read docs](https://doc.rust-lang.org/std/fs/fn.read.html), [fs::read_to_string docs](https://doc.rust-lang.org/std/fs/fn.read_to_string.html)
-    ///
-    /// ### Example
-    /// ```rust,no_run
-    /// # use std::io::Read;
-    /// # use std::fs::File;
-    /// let mut f = File::open("foo.txt").unwrap();
-    /// let mut bytes = Vec::new();
-    /// f.read_to_end(&mut bytes).unwrap();
-    /// ```
-    /// Can be written more concisely as
-    /// ```rust,no_run
-    /// # use std::fs;
-    /// let mut bytes = fs::read("foo.txt").unwrap();
-    /// ```
-    #[clippy::version = "1.44.0"]
-    pub VERBOSE_FILE_READS,
-    restriction,
-    "use of `File::read_to_end` or `File::read_to_string`"
-}
-
-declare_lint_pass!(VerboseFileReads => [VERBOSE_FILE_READS]);
-
-impl<'tcx> LateLintPass<'tcx> for VerboseFileReads {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
-        if is_file_read_to_end(cx, expr) {
-            span_lint_and_help(
-                cx,
-                VERBOSE_FILE_READS,
-                expr.span,
-                "use of `File::read_to_end`",
-                None,
-                "consider using `fs::read` instead",
-            );
-        } else if is_file_read_to_string(cx, expr) {
-            span_lint_and_help(
-                cx,
-                VERBOSE_FILE_READS,
-                expr.span,
-                "use of `File::read_to_string`",
-                None,
-                "consider using `fs::read_to_string` instead",
-            );
-        }
-    }
-}
-
-fn is_file_read_to_end<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
-    if_chain! {
-        if let ExprKind::MethodCall(method_name, [recv, ..], _) = expr.kind;
-        if method_name.ident.as_str() == "read_to_end";
-        if let ExprKind::Path(QPath::Resolved(None, _)) = &recv.kind;
-        let ty = cx.typeck_results().expr_ty(recv);
-        if match_type(cx, ty, &paths::FILE);
-        then {
-            return true
-        }
-    }
-    false
-}
-
-fn is_file_read_to_string<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
-    if_chain! {
-        if let ExprKind::MethodCall(method_name, exprs, _) = expr.kind;
-        if method_name.ident.as_str() == "read_to_string";
-        if let ExprKind::Path(QPath::Resolved(None, _)) = &exprs[0].kind;
-        let ty = cx.typeck_results().expr_ty(&exprs[0]);
-        if match_type(cx, ty, &paths::FILE);
-        then {
-            return true
-        }
-    }
-    false
-}
diff --git a/src/tools/clippy/clippy_lints/src/wildcard_imports.rs b/src/tools/clippy/clippy_lints/src/wildcard_imports.rs
index 5418eca382da..2604b1ee7c56 100644
--- a/src/tools/clippy/clippy_lints/src/wildcard_imports.rs
+++ b/src/tools/clippy/clippy_lints/src/wildcard_imports.rs
@@ -120,14 +120,14 @@ impl LateLintPass<'_> for WildcardImports {
         if is_test_module_or_function(cx.tcx, item) {
             self.test_modules_deep = self.test_modules_deep.saturating_add(1);
         }
-        let module = cx.tcx.parent_module_from_def_id(item.def_id);
-        if cx.tcx.visibility(item.def_id) != ty::Visibility::Restricted(module.to_def_id()) {
+        let module = cx.tcx.parent_module_from_def_id(item.def_id.def_id);
+        if cx.tcx.visibility(item.def_id.def_id) != ty::Visibility::Restricted(module.to_def_id()) {
             return;
         }
         if_chain! {
             if let ItemKind::Use(use_path, UseKind::Glob) = &item.kind;
             if self.warn_on_all || !self.check_exceptions(item, use_path.segments);
-            let used_imports = cx.tcx.names_imported_by_glob_use(item.def_id);
+            let used_imports = cx.tcx.names_imported_by_glob_use(item.def_id.def_id);
             if !used_imports.is_empty(); // Already handled by `unused_imports`
             then {
                 let mut applicability = Applicability::MachineApplicable;
diff --git a/src/tools/clippy/clippy_lints/src/write.rs b/src/tools/clippy/clippy_lints/src/write.rs
index fa2383066f3f..06e7d7017017 100644
--- a/src/tools/clippy/clippy_lints/src/write.rs
+++ b/src/tools/clippy/clippy_lints/src/write.rs
@@ -1,19 +1,12 @@
-use std::borrow::Cow;
-use std::iter;
-use std::ops::{Deref, Range};
-
-use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then};
-use clippy_utils::source::{snippet_opt, snippet_with_applicability};
-use rustc_ast::ast::{Expr, ExprKind, Impl, Item, ItemKind, MacCall, Path, StrLit, StrStyle};
-use rustc_ast::token::{self, LitKind};
-use rustc_ast::tokenstream::TokenStream;
-use rustc_errors::{Applicability, DiagnosticBuilder};
-use rustc_lexer::unescape::{self, EscapeError};
-use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
-use rustc_parse::parser;
+use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
+use clippy_utils::macros::{root_macro_call_first_node, FormatArgsExpn, MacroCall};
+use clippy_utils::source::snippet_opt;
+use rustc_ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind, HirIdMap, Impl, Item, ItemKind};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::symbol::{kw, Symbol};
-use rustc_span::{sym, BytePos, InnerSpan, Span, DUMMY_SP};
+use rustc_span::{sym, BytePos, Span};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -73,13 +66,7 @@ declare_clippy_lint! {
     /// application and might forget to remove those prints afterward.
     ///
     /// ### Known problems
-    /// * Only catches `print!` and `println!` calls.
-    /// * The lint level is unaffected by crate attributes. The level can still
-    ///   be set for functions, modules and other items. To change the level for
-    ///   the entire crate, please use command line flags. More information and a
-    ///   configuration example can be found in [clippy#6610].
-    ///
-    /// [clippy#6610]: https://github.com/rust-lang/rust-clippy/issues/6610#issuecomment-977120558
+    /// Only catches `print!` and `println!` calls.
     ///
     /// ### Example
     /// ```rust
@@ -101,13 +88,7 @@ declare_clippy_lint! {
     /// application and might forget to remove those prints afterward.
     ///
     /// ### Known problems
-    /// * Only catches `eprint!` and `eprintln!` calls.
-    /// * The lint level is unaffected by crate attributes. The level can still
-    ///   be set for functions, modules and other items. To change the level for
-    ///   the entire crate, please use command line flags. More information and a
-    ///   configuration example can be found in [clippy#6610].
-    ///
-    /// [clippy#6610]: https://github.com/rust-lang/rust-clippy/issues/6610#issuecomment-977120558
+    /// Only catches `eprint!` and `eprintln!` calls.
     ///
     /// ### Example
     /// ```rust
@@ -148,10 +129,6 @@ declare_clippy_lint! {
     /// (c.f., https://github.com/matthiaskrgr/rust-str-bench) and unnecessary
     /// (i.e., just put the literal in the format string)
     ///
-    /// ### Known problems
-    /// Will also warn with macro calls as arguments that expand to literals
-    /// -- e.g., `println!("{}", env!("FOO"))`.
-    ///
     /// ### Example
     /// ```rust
     /// println!("{}", "foo");
@@ -233,10 +210,6 @@ declare_clippy_lint! {
     /// (c.f., https://github.com/matthiaskrgr/rust-str-bench) and unnecessary
     /// (i.e., just put the literal in the format string)
     ///
-    /// ### Known problems
-    /// Will also warn with macro calls as arguments that expand to literals
-    /// -- e.g., `writeln!(buf, "{}", env!("FOO"))`.
-    ///
     /// ### Example
     /// ```rust
     /// # use std::fmt::Write;
@@ -270,440 +243,309 @@ impl_lint_pass!(Write => [
     PRINT_LITERAL,
     WRITE_WITH_NEWLINE,
     WRITELN_EMPTY_STRING,
-    WRITE_LITERAL
+    WRITE_LITERAL,
 ]);
 
-impl EarlyLintPass for Write {
-    fn check_item(&mut self, _: &EarlyContext<'_>, item: &Item) {
-        if let ItemKind::Impl(box Impl {
-            of_trait: Some(trait_ref),
-            ..
-        }) = &item.kind
-        {
-            let trait_name = trait_ref
-                .path
-                .segments
-                .iter()
-                .last()
-                .expect("path has at least one segment")
-                .ident
-                .name;
-            if trait_name == sym::Debug {
-                self.in_debug_impl = true;
-            }
+impl<'tcx> LateLintPass<'tcx> for Write {
+    fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
+        if is_debug_impl(cx, item) {
+            self.in_debug_impl = true;
         }
     }
 
-    fn check_item_post(&mut self, _: &EarlyContext<'_>, _: &Item) {
-        self.in_debug_impl = false;
+    fn check_item_post(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
+        if is_debug_impl(cx, item) {
+            self.in_debug_impl = false;
+        }
     }
 
-    fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &MacCall) {
-        fn is_build_script(cx: &EarlyContext<'_>) -> bool {
-            // Cargo sets the crate name for build scripts to `build_script_build`
-            cx.sess()
-                .opts
-                .crate_name
-                .as_ref()
-                .map_or(false, |crate_name| crate_name == "build_script_build")
-        }
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        let Some(macro_call) = root_macro_call_first_node(cx, expr) else { return };
+        let Some(diag_name) = cx.tcx.get_diagnostic_name(macro_call.def_id) else { return };
+        let Some(name) = diag_name.as_str().strip_suffix("_macro") else { return };
 
-        if mac.path == sym!(print) {
-            if !is_build_script(cx) {
-                span_lint(cx, PRINT_STDOUT, mac.span(), "use of `print!`");
-            }
-            self.lint_print_with_newline(cx, mac);
-        } else if mac.path == sym!(println) {
-            if !is_build_script(cx) {
-                span_lint(cx, PRINT_STDOUT, mac.span(), "use of `println!`");
-            }
-            self.lint_println_empty_string(cx, mac);
-        } else if mac.path == sym!(eprint) {
-            span_lint(cx, PRINT_STDERR, mac.span(), "use of `eprint!`");
-            self.lint_print_with_newline(cx, mac);
-        } else if mac.path == sym!(eprintln) {
-            span_lint(cx, PRINT_STDERR, mac.span(), "use of `eprintln!`");
-            self.lint_println_empty_string(cx, mac);
-        } else if mac.path == sym!(write) {
-            if let (Some(fmt_str), dest) = self.check_tts(cx, mac.args.inner_tokens(), true) {
-                if check_newlines(&fmt_str) {
-                    let (nl_span, only_nl) = newline_span(&fmt_str);
-                    let nl_span = match (dest, only_nl) {
-                        // Special case of `write!(buf, "\n")`: Mark everything from the end of
-                        // `buf` for removal so no trailing comma [`writeln!(buf, )`] remains.
-                        (Some(dest_expr), true) => nl_span.with_lo(dest_expr.span.hi()),
-                        _ => nl_span,
-                    };
-                    span_lint_and_then(
-                        cx,
-                        WRITE_WITH_NEWLINE,
-                        mac.span(),
-                        "using `write!()` with a format string that ends in a single newline",
-                        |err| {
-                            err.multipart_suggestion(
-                                "use `writeln!()` instead",
-                                vec![(mac.path.span, String::from("writeln")), (nl_span, String::new())],
-                                Applicability::MachineApplicable,
-                            );
-                        },
-                    );
+        let is_build_script = cx
+            .sess()
+            .opts
+            .crate_name
+            .as_ref()
+            .map_or(false, |crate_name| crate_name == "build_script_build");
+
+        match diag_name {
+            sym::print_macro | sym::println_macro => {
+                if !is_build_script {
+                    span_lint(cx, PRINT_STDOUT, macro_call.span, &format!("use of `{name}!`"));
                 }
-            }
-        } else if mac.path == sym!(writeln) {
-            if let (Some(fmt_str), expr) = self.check_tts(cx, mac.args.inner_tokens(), true) {
-                if fmt_str.symbol == kw::Empty {
-                    let mut applicability = Applicability::MachineApplicable;
-                    let suggestion = if let Some(e) = expr {
-                        snippet_with_applicability(cx, e.span, "v", &mut applicability)
-                    } else {
-                        applicability = Applicability::HasPlaceholders;
-                        Cow::Borrowed("v")
-                    };
+            },
+            sym::eprint_macro | sym::eprintln_macro => {
+                span_lint(cx, PRINT_STDERR, macro_call.span, &format!("use of `{name}!`"));
+            },
+            sym::write_macro | sym::writeln_macro => {},
+            _ => return,
+        }
 
-                    span_lint_and_sugg(
-                        cx,
-                        WRITELN_EMPTY_STRING,
-                        mac.span(),
-                        format!("using `writeln!({}, \"\")`", suggestion).as_str(),
-                        "replace it with",
-                        format!("writeln!({})", suggestion),
-                        applicability,
-                    );
+        let Some(format_args) = FormatArgsExpn::find_nested(cx, expr, macro_call.expn) else { return };
+
+        // ignore `writeln!(w)` and `write!(v, some_macro!())`
+        if format_args.format_string.span.from_expansion() {
+            return;
+        }
+
+        match diag_name {
+            sym::print_macro | sym::eprint_macro | sym::write_macro => {
+                check_newline(cx, &format_args, &macro_call, name);
+            },
+            sym::println_macro | sym::eprintln_macro | sym::writeln_macro => {
+                check_empty_string(cx, &format_args, &macro_call, name);
+            },
+            _ => {},
+        }
+
+        check_literal(cx, &format_args, name);
+
+        if !self.in_debug_impl {
+            for arg in &format_args.args {
+                if arg.format.r#trait == sym::Debug {
+                    span_lint(cx, USE_DEBUG, arg.span, "use of `Debug`-based formatting");
                 }
             }
         }
     }
 }
-
-/// Given a format string that ends in a newline and its span, calculates the span of the
-/// newline, or the format string itself if the format string consists solely of a newline.
-/// Return this and a boolean indicating whether it only consisted of a newline.
-fn newline_span(fmtstr: &StrLit) -> (Span, bool) {
-    let sp = fmtstr.span;
-    let contents = fmtstr.symbol.as_str();
-
-    if contents == r"\n" {
-        return (sp, true);
-    }
-
-    let newline_sp_hi = sp.hi()
-        - match fmtstr.style {
-            StrStyle::Cooked => BytePos(1),
-            StrStyle::Raw(hashes) => BytePos((1 + hashes).into()),
-        };
-
-    let newline_sp_len = if contents.ends_with('\n') {
-        BytePos(1)
-    } else if contents.ends_with(r"\n") {
-        BytePos(2)
+fn is_debug_impl(cx: &LateContext<'_>, item: &Item<'_>) -> bool {
+    if let ItemKind::Impl(Impl { of_trait: Some(trait_ref), .. }) = &item.kind
+        && let Some(trait_id) = trait_ref.trait_def_id()
+    {
+        cx.tcx.is_diagnostic_item(sym::Debug, trait_id)
     } else {
-        panic!("expected format string to contain a newline");
+        false
+    }
+}
+
+fn check_newline(cx: &LateContext<'_>, format_args: &FormatArgsExpn<'_>, macro_call: &MacroCall, name: &str) {
+    let format_string_parts = &format_args.format_string.parts;
+    let mut format_string_span = format_args.format_string.span;
+
+    let Some(last) = format_string_parts.last() else { return };
+
+    let count_vertical_whitespace = || {
+        format_string_parts
+            .iter()
+            .flat_map(|part| part.as_str().chars())
+            .filter(|ch| matches!(ch, '\r' | '\n'))
+            .count()
     };
 
-    (sp.with_lo(newline_sp_hi - newline_sp_len).with_hi(newline_sp_hi), false)
-}
+    if last.as_str().ends_with('\n')
+        // ignore format strings with other internal vertical whitespace
+        && count_vertical_whitespace() == 1
 
-/// Stores a list of replacement spans for each argument, but only if all the replacements used an
-/// empty format string.
-#[derive(Default)]
-struct SimpleFormatArgs {
-    unnamed: Vec<Vec<Span>>,
-    named: Vec<(Symbol, Vec<Span>)>,
-}
-impl SimpleFormatArgs {
-    fn get_unnamed(&self) -> impl Iterator<Item = &[Span]> {
-        self.unnamed.iter().map(|x| match x.as_slice() {
-            // Ignore the dummy span added from out of order format arguments.
-            [DUMMY_SP] => &[],
-            x => x,
-        })
-    }
+        // ignore trailing arguments: `print!("Issue\n{}", 1265);`
+        && format_string_parts.len() > format_args.args.len()
+    {
+        let lint = if name == "write" {
+            format_string_span = expand_past_previous_comma(cx, format_string_span);
 
-    fn get_named(&self, n: &Path) -> &[Span] {
-        self.named.iter().find(|x| *n == x.0).map_or(&[], |x| x.1.as_slice())
-    }
-
-    fn push(&mut self, arg: rustc_parse_format::Argument<'_>, span: Span) {
-        use rustc_parse_format::{
-            AlignUnknown, ArgumentImplicitlyIs, ArgumentIs, ArgumentNamed, CountImplied, FormatSpec,
-        };
-
-        const SIMPLE: FormatSpec<'_> = FormatSpec {
-            fill: None,
-            align: AlignUnknown,
-            flags: 0,
-            precision: CountImplied,
-            precision_span: None,
-            width: CountImplied,
-            width_span: None,
-            ty: "",
-            ty_span: None,
-        };
-
-        match arg.position {
-            ArgumentIs(n) | ArgumentImplicitlyIs(n) => {
-                if self.unnamed.len() <= n {
-                    // Use a dummy span to mark all unseen arguments.
-                    self.unnamed.resize_with(n, || vec![DUMMY_SP]);
-                    if arg.format == SIMPLE {
-                        self.unnamed.push(vec![span]);
-                    } else {
-                        self.unnamed.push(Vec::new());
-                    }
-                } else {
-                    let args = &mut self.unnamed[n];
-                    match (args.as_mut_slice(), arg.format == SIMPLE) {
-                        // A non-empty format string has been seen already.
-                        ([], _) => (),
-                        // Replace the dummy span, if it exists.
-                        ([dummy @ DUMMY_SP], true) => *dummy = span,
-                        ([_, ..], true) => args.push(span),
-                        ([_, ..], false) => *args = Vec::new(),
-                    }
-                }
-            },
-            ArgumentNamed(n) => {
-                let n = Symbol::intern(n);
-                if let Some(x) = self.named.iter_mut().find(|x| x.0 == n) {
-                    match x.1.as_slice() {
-                        // A non-empty format string has been seen already.
-                        [] => (),
-                        [_, ..] if arg.format == SIMPLE => x.1.push(span),
-                        [_, ..] => x.1 = Vec::new(),
-                    }
-                } else if arg.format == SIMPLE {
-                    self.named.push((n, vec![span]));
-                } else {
-                    self.named.push((n, Vec::new()));
-                }
-            },
-        };
-    }
-}
-
-impl Write {
-    /// Parses a format string into a collection of spans for each argument. This only keeps track
-    /// of empty format arguments. Will also lint usages of debug format strings outside of debug
-    /// impls.
-    fn parse_fmt_string(&self, cx: &EarlyContext<'_>, str_lit: &StrLit) -> Option<SimpleFormatArgs> {
-        use rustc_parse_format::{ParseMode, Parser, Piece};
-
-        let str_sym = str_lit.symbol_unescaped.as_str();
-        let style = match str_lit.style {
-            StrStyle::Cooked => None,
-            StrStyle::Raw(n) => Some(n as usize),
-        };
-
-        let mut parser = Parser::new(str_sym, style, snippet_opt(cx, str_lit.span), false, ParseMode::Format);
-        let mut args = SimpleFormatArgs::default();
-
-        while let Some(arg) = parser.next() {
-            let arg = match arg {
-                Piece::String(_) => continue,
-                Piece::NextArgument(arg) => arg,
-            };
-            let span = parser
-                .arg_places
-                .last()
-                .map_or(DUMMY_SP, |&x| str_lit.span.from_inner(InnerSpan::new(x.start, x.end)));
-
-            if !self.in_debug_impl && arg.format.ty == "?" {
-                // FIXME: modify rustc's fmt string parser to give us the current span
-                span_lint(cx, USE_DEBUG, span, "use of `Debug`-based formatting");
-            }
-
-            args.push(arg, span);
-        }
-
-        parser.errors.is_empty().then_some(args)
-    }
-
-    /// Checks the arguments of `print[ln]!` and `write[ln]!` calls. It will return a tuple of two
-    /// `Option`s. The first `Option` of the tuple is the macro's format string. It includes
-    /// the contents of the string, whether it's a raw string, and the span of the literal in the
-    /// source. The second `Option` in the tuple is, in the `write[ln]!` case, the expression the
-    /// `format_str` should be written to.
-    ///
-    /// Example:
-    ///
-    /// Calling this function on
-    /// ```rust
-    /// # use std::fmt::Write;
-    /// # let mut buf = String::new();
-    /// # let something = "something";
-    /// writeln!(buf, "string to write: {}", something);
-    /// ```
-    /// will return
-    /// ```rust,ignore
-    /// (Some("string to write: {}"), Some(buf))
-    /// ```
-    fn check_tts<'a>(&self, cx: &EarlyContext<'a>, tts: TokenStream, is_write: bool) -> (Option<StrLit>, Option<Expr>) {
-        let mut parser = parser::Parser::new(&cx.sess().parse_sess, tts, false, None);
-        let expr = if is_write {
-            match parser
-                .parse_expr()
-                .map(rustc_ast::ptr::P::into_inner)
-                .map_err(DiagnosticBuilder::cancel)
-            {
-                // write!(e, ...)
-                Ok(p) if parser.eat(&token::Comma) => Some(p),
-                // write!(e) or error
-                e => return (None, e.ok()),
-            }
+            WRITE_WITH_NEWLINE
         } else {
-            None
+            PRINT_WITH_NEWLINE
         };
 
-        let fmtstr = match parser.parse_str_lit() {
-            Ok(fmtstr) => fmtstr,
-            Err(_) => return (None, expr),
-        };
+        span_lint_and_then(
+            cx,
+            lint,
+            macro_call.span,
+            &format!("using `{name}!()` with a format string that ends in a single newline"),
+            |diag| {
+                let name_span = cx.sess().source_map().span_until_char(macro_call.span, '!');
+                let Some(format_snippet) = snippet_opt(cx, format_string_span) else { return };
 
-        let args = match self.parse_fmt_string(cx, &fmtstr) {
-            Some(args) => args,
-            None => return (Some(fmtstr), expr),
-        };
+                if format_string_parts.len() == 1 && last.as_str() == "\n" {
+                    // print!("\n"), write!(f, "\n")
 
-        let lint = if is_write { WRITE_LITERAL } else { PRINT_LITERAL };
-        let mut unnamed_args = args.get_unnamed();
-        loop {
-            if !parser.eat(&token::Comma) {
-                return (Some(fmtstr), expr);
-            }
+                    diag.multipart_suggestion(
+                        &format!("use `{name}ln!` instead"),
+                        vec![(name_span, format!("{name}ln")), (format_string_span, String::new())],
+                        Applicability::MachineApplicable,
+                    );
+                } else if format_snippet.ends_with("\\n\"") {
+                    // print!("...\n"), write!(f, "...\n")
 
-            let comma_span = parser.prev_token.span;
-            let token_expr = if let Ok(expr) = parser.parse_expr().map_err(DiagnosticBuilder::cancel) {
-                expr
-            } else {
-                return (Some(fmtstr), None);
-            };
-            let (fmt_spans, lit) = match &token_expr.kind {
-                ExprKind::Lit(lit) => (unnamed_args.next().unwrap_or(&[]), lit),
-                ExprKind::Assign(lhs, rhs, _) => match (&lhs.kind, &rhs.kind) {
-                    (ExprKind::Path(_, p), ExprKind::Lit(lit)) => (args.get_named(p), lit),
-                    _ => continue,
-                },
-                _ => {
-                    unnamed_args.next();
-                    continue;
-                },
-            };
+                    let hi = format_string_span.hi();
+                    let newline_span = format_string_span.with_lo(hi - BytePos(3)).with_hi(hi - BytePos(1));
 
-            let replacement: String = match lit.token_lit.kind {
-                LitKind::StrRaw(_) | LitKind::ByteStrRaw(_) if matches!(fmtstr.style, StrStyle::Raw(_)) => {
-                    lit.token_lit.symbol.as_str().replace('{', "{{").replace('}', "}}")
-                },
-                LitKind::Str | LitKind::ByteStr if matches!(fmtstr.style, StrStyle::Cooked) => {
-                    lit.token_lit.symbol.as_str().replace('{', "{{").replace('}', "}}")
-                },
-                LitKind::StrRaw(_)
-                | LitKind::Str
-                | LitKind::ByteStrRaw(_)
-                | LitKind::ByteStr
-                | LitKind::Integer
-                | LitKind::Float
-                | LitKind::Err => continue,
-                LitKind::Byte | LitKind::Char => match lit.token_lit.symbol.as_str() {
-                    "\"" if matches!(fmtstr.style, StrStyle::Cooked) => "\\\"",
-                    "\"" if matches!(fmtstr.style, StrStyle::Raw(0)) => continue,
-                    "\\\\" if matches!(fmtstr.style, StrStyle::Raw(_)) => "\\",
-                    "\\'" => "'",
-                    "{" => "{{",
-                    "}" => "}}",
-                    x if matches!(fmtstr.style, StrStyle::Raw(_)) && x.starts_with('\\') => continue,
-                    x => x,
+                    diag.multipart_suggestion(
+                        &format!("use `{name}ln!` instead"),
+                        vec![(name_span, format!("{name}ln")), (newline_span, String::new())],
+                        Applicability::MachineApplicable,
+                    );
                 }
-                .into(),
-                LitKind::Bool => lit.token_lit.symbol.as_str().deref().into(),
-            };
-
-            if !fmt_spans.is_empty() {
-                span_lint_and_then(
-                    cx,
-                    lint,
-                    token_expr.span,
-                    "literal with an empty format string",
-                    |diag| {
-                        diag.multipart_suggestion(
-                            "try this",
-                            iter::once((comma_span.to(token_expr.span), String::new()))
-                                .chain(fmt_spans.iter().copied().zip(iter::repeat(replacement)))
-                                .collect(),
-                            Applicability::MachineApplicable,
-                        );
-                    },
-                );
-            }
-        }
+            },
+        );
     }
+}
 
-    fn lint_println_empty_string(&self, cx: &EarlyContext<'_>, mac: &MacCall) {
-        if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), false) {
-            if fmt_str.symbol == kw::Empty {
-                let name = mac.path.segments[0].ident.name;
-                span_lint_and_sugg(
-                    cx,
-                    PRINTLN_EMPTY_STRING,
-                    mac.span(),
-                    &format!("using `{}!(\"\")`", name),
-                    "replace it with",
-                    format!("{}!()", name),
+fn check_empty_string(cx: &LateContext<'_>, format_args: &FormatArgsExpn<'_>, macro_call: &MacroCall, name: &str) {
+    if let [part] = &format_args.format_string.parts[..]
+        && let mut span = format_args.format_string.span
+        && part.as_str() == "\n"
+    {
+        let lint = if name == "writeln" {
+            span = expand_past_previous_comma(cx, span);
+
+            WRITELN_EMPTY_STRING
+        } else {
+            PRINTLN_EMPTY_STRING
+        };
+
+        span_lint_and_then(
+            cx,
+            lint,
+            macro_call.span,
+            &format!("empty string literal in `{name}!`"),
+            |diag| {
+                diag.span_suggestion(
+                    span,
+                    "remove the empty string",
+                    String::new(),
                     Applicability::MachineApplicable,
                 );
-            }
-        }
+            },
+        );
+    }
+}
+
+fn check_literal(cx: &LateContext<'_>, format_args: &FormatArgsExpn<'_>, name: &str) {
+    let mut counts = HirIdMap::<usize>::default();
+    for param in format_args.params() {
+        *counts.entry(param.value.hir_id).or_default() += 1;
     }
 
-    fn lint_print_with_newline(&self, cx: &EarlyContext<'_>, mac: &MacCall) {
-        if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), false) {
-            if check_newlines(&fmt_str) {
-                let name = mac.path.segments[0].ident.name;
-                let suggested = format!("{}ln", name);
-                span_lint_and_then(
-                    cx,
-                    PRINT_WITH_NEWLINE,
-                    mac.span(),
-                    &format!("using `{}!()` with a format string that ends in a single newline", name),
-                    |err| {
-                        err.multipart_suggestion(
-                            &format!("use `{}!` instead", suggested),
-                            vec![(mac.path.span, suggested), (newline_span(&fmt_str).0, String::new())],
+    for arg in &format_args.args {
+        let value = arg.param.value;
+
+        if counts[&value.hir_id] == 1
+            && arg.format.is_default()
+            && let ExprKind::Lit(lit) = &value.kind
+            && !value.span.from_expansion()
+            && let Some(value_string) = snippet_opt(cx, value.span)
+        {
+            let (replacement, replace_raw) = match lit.node {
+                LitKind::Str(..) => extract_str_literal(&value_string),
+                LitKind::Char(ch) => (
+                    match ch {
+                        '"' => "\\\"",
+                        '\'' => "'",
+                        _ => &value_string[1..value_string.len() - 1],
+                    }
+                    .to_string(),
+                    false,
+                ),
+                LitKind::Bool(b) => (b.to_string(), false),
+                _ => continue,
+            };
+
+            let lint = if name.starts_with("write") {
+                WRITE_LITERAL
+            } else {
+                PRINT_LITERAL
+            };
+
+            let format_string_is_raw = format_args.format_string.style.is_some();
+            let replacement = match (format_string_is_raw, replace_raw) {
+                (false, false) => Some(replacement),
+                (false, true) => Some(replacement.replace('"', "\\\"").replace('\\', "\\\\")),
+                (true, false) => match conservative_unescape(&replacement) {
+                    Ok(unescaped) => Some(unescaped),
+                    Err(UnescapeErr::Lint) => None,
+                    Err(UnescapeErr::Ignore) => continue,
+                },
+                (true, true) => {
+                    if replacement.contains(['#', '"']) {
+                        None
+                    } else {
+                        Some(replacement)
+                    }
+                },
+            };
+
+            span_lint_and_then(
+                cx,
+                lint,
+                value.span,
+                "literal with an empty format string",
+                |diag| {
+                    if let Some(replacement) = replacement {
+                        // `format!("{}", "a")`, `format!("{named}", named = "b")
+                        //              ~~~~~                      ~~~~~~~~~~~~~
+                        let value_span = expand_past_previous_comma(cx, value.span);
+
+                        let replacement = replacement.replace('{', "{{").replace('}', "}}");
+                        diag.multipart_suggestion(
+                            "try this",
+                            vec![(arg.span, replacement), (value_span, String::new())],
                             Applicability::MachineApplicable,
                         );
-                    },
-                );
-            }
+                    }
+                },
+            );
         }
     }
 }
 
-/// Checks if the format string contains a single newline that terminates it.
+/// Removes the raw marker, `#`s and quotes from a str, and returns if the literal is raw
 ///
-/// Literal and escaped newlines are both checked (only literal for raw strings).
-fn check_newlines(fmtstr: &StrLit) -> bool {
-    let mut has_internal_newline = false;
-    let mut last_was_cr = false;
-    let mut should_lint = false;
-
-    let contents = fmtstr.symbol.as_str();
-
-    let mut cb = |r: Range<usize>, c: Result<char, EscapeError>| {
-        let c = c.unwrap();
-
-        if r.end == contents.len() && c == '\n' && !last_was_cr && !has_internal_newline {
-            should_lint = true;
-        } else {
-            last_was_cr = c == '\r';
-            if c == '\n' {
-                has_internal_newline = true;
-            }
-        }
+/// `r#"a"#` -> (`a`, true)
+///
+/// `"b"` -> (`b`, false)
+fn extract_str_literal(literal: &str) -> (String, bool) {
+    let (literal, raw) = match literal.strip_prefix('r') {
+        Some(stripped) => (stripped.trim_matches('#'), true),
+        None => (literal, false),
     };
 
-    match fmtstr.style {
-        StrStyle::Cooked => unescape::unescape_literal(contents, unescape::Mode::Str, &mut cb),
-        StrStyle::Raw(_) => unescape::unescape_literal(contents, unescape::Mode::RawStr, &mut cb),
+    (literal[1..literal.len() - 1].to_string(), raw)
+}
+
+enum UnescapeErr {
+    /// Should still be linted, can be manually resolved by author, e.g.
+    ///
+    /// ```ignore
+    /// print!(r"{}", '"');
+    /// ```
+    Lint,
+    /// Should not be linted, e.g.
+    ///
+    /// ```ignore
+    /// print!(r"{}", '\r');
+    /// ```
+    Ignore,
+}
+
+/// Unescape a normal string into a raw string
+fn conservative_unescape(literal: &str) -> Result<String, UnescapeErr> {
+    let mut unescaped = String::with_capacity(literal.len());
+    let mut chars = literal.chars();
+    let mut err = false;
+
+    while let Some(ch) = chars.next() {
+        match ch {
+            '#' => err = true,
+            '\\' => match chars.next() {
+                Some('\\') => unescaped.push('\\'),
+                Some('"') => err = true,
+                _ => return Err(UnescapeErr::Ignore),
+            },
+            _ => unescaped.push(ch),
+        }
     }
 
-    should_lint
+    if err { Err(UnescapeErr::Lint) } else { Ok(unescaped) }
+}
+
+// Expand from `writeln!(o, "")` to `writeln!(o, "")`
+//                          ^^                 ^^^^
+fn expand_past_previous_comma(cx: &LateContext<'_>, span: Span) -> Span {
+    let extended = cx.sess().source_map().span_extend_to_prev_char(span, ',', true);
+    extended.with_lo(extended.lo() - BytePos(1))
 }
diff --git a/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs b/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs
index 8dc43c0e2943..386f3c527f17 100644
--- a/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs
+++ b/src/tools/clippy/clippy_lints/src/zero_sized_map_values.rs
@@ -72,7 +72,7 @@ fn in_trait_impl(cx: &LateContext<'_>, hir_id: HirId) -> bool {
     let second_parent_id = cx
         .tcx
         .hir()
-        .get_parent_item(cx.tcx.hir().local_def_id_to_hir_id(parent_id));
+        .get_parent_item(parent_id.into()).def_id;
     if let Some(Node::Item(item)) = cx.tcx.hir().find_by_def_id(second_parent_id) {
         if let ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = item.kind {
             return true;
diff --git a/src/tools/clippy/clippy_utils/Cargo.toml b/src/tools/clippy/clippy_utils/Cargo.toml
index a688050f63a6..c36bca06507d 100644
--- a/src/tools/clippy/clippy_utils/Cargo.toml
+++ b/src/tools/clippy/clippy_utils/Cargo.toml
@@ -7,6 +7,7 @@ publish = false
 [dependencies]
 arrayvec = { version = "0.7", default-features = false }
 if_chain = "1.0"
+itertools = "0.10.1"
 rustc-semver = "1.1"
 
 [features]
diff --git a/src/tools/clippy/clippy_utils/src/check_proc_macro.rs b/src/tools/clippy/clippy_utils/src/check_proc_macro.rs
index 8335ffae81eb..7a8d4e8068ed 100644
--- a/src/tools/clippy/clippy_utils/src/check_proc_macro.rs
+++ b/src/tools/clippy/clippy_utils/src/check_proc_macro.rs
@@ -118,9 +118,9 @@ fn expr_search_pat(tcx: TyCtxt<'_>, e: &Expr<'_>) -> (Pat, Pat) {
         ExprKind::Unary(UnOp::Neg, e) => (Pat::Str("-"), expr_search_pat(tcx, e).1),
         ExprKind::Lit(ref lit) => lit_search_pat(&lit.node),
         ExprKind::Array(_) | ExprKind::Repeat(..) => (Pat::Str("["), Pat::Str("]")),
-        ExprKind::Call(e, []) | ExprKind::MethodCall(_, [e], _) => (expr_search_pat(tcx, e).0, Pat::Str("(")),
+        ExprKind::Call(e, []) | ExprKind::MethodCall(_, e, [], _) => (expr_search_pat(tcx, e).0, Pat::Str("(")),
         ExprKind::Call(first, [.., last])
-        | ExprKind::MethodCall(_, [first, .., last], _)
+        | ExprKind::MethodCall(_, first, [.., last], _)
         | ExprKind::Binary(_, first, last)
         | ExprKind::Tup([first, .., last])
         | ExprKind::Assign(first, last, _)
@@ -140,7 +140,7 @@ fn expr_search_pat(tcx: TyCtxt<'_>, e: &Expr<'_>) -> (Pat, Pat) {
         ExprKind::Match(e, _, MatchSource::AwaitDesugar) | ExprKind::Yield(e, YieldSource::Await { .. }) => {
             (expr_search_pat(tcx, e).0, Pat::Str("await"))
         },
-        ExprKind::Closure(&Closure { body, .. }) => (Pat::Str(""), expr_search_pat(tcx, &tcx.hir().body(body).value).1),
+        ExprKind::Closure(&Closure { body, .. }) => (Pat::Str(""), expr_search_pat(tcx, tcx.hir().body(body).value).1),
         ExprKind::Block(
             Block {
                 rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
@@ -254,7 +254,7 @@ fn fn_kind_pat(tcx: TyCtxt<'_>, kind: &FnKind<'_>, body: &Body<'_>, hir_id: HirI
     let (start_pat, end_pat) = match kind {
         FnKind::ItemFn(.., header) => (fn_header_search_pat(*header), Pat::Str("")),
         FnKind::Method(.., sig) => (fn_header_search_pat(sig.header), Pat::Str("")),
-        FnKind::Closure => return (Pat::Str(""), expr_search_pat(tcx, &body.value).1),
+        FnKind::Closure => return (Pat::Str(""), expr_search_pat(tcx, body.value).1),
     };
     let start_pat = match tcx.hir().get(hir_id) {
         Node::Item(Item { vis_span, .. }) | Node::ImplItem(ImplItem { vis_span, .. }) => {
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index e053708edd50..fa6766f7cfe1 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -9,7 +9,7 @@ use rustc_hir::{BinOp, BinOpKind, Block, Expr, ExprKind, HirId, Item, ItemKind,
 use rustc_lint::LateContext;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::Scalar;
-use rustc_middle::ty::subst::{Subst, SubstsRef};
+use rustc_middle::ty::SubstsRef;
 use rustc_middle::ty::{self, EarlyBinder, FloatTy, ScalarInt, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_span::symbol::Symbol;
@@ -424,7 +424,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                     .tcx
                     .const_eval_resolve(
                         self.param_env,
-                        ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs),
+                        mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs),
                         None,
                     )
                     .ok()
@@ -501,8 +501,8 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                         BinOpKind::Mul => l.checked_mul(r).map(zext),
                         BinOpKind::Div if r != 0 => l.checked_div(r).map(zext),
                         BinOpKind::Rem if r != 0 => l.checked_rem(r).map(zext),
-                        BinOpKind::Shr => l.checked_shr(r.try_into().expect("invalid shift")).map(zext),
-                        BinOpKind::Shl => l.checked_shl(r.try_into().expect("invalid shift")).map(zext),
+                        BinOpKind::Shr => l.checked_shr(r.try_into().ok()?).map(zext),
+                        BinOpKind::Shl => l.checked_shl(r.try_into().ok()?).map(zext),
                         BinOpKind::BitXor => Some(zext(l ^ r)),
                         BinOpKind::BitOr => Some(zext(l | r)),
                         BinOpKind::BitAnd => Some(zext(l & r)),
@@ -521,8 +521,8 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                     BinOpKind::Mul => l.checked_mul(r).map(Constant::Int),
                     BinOpKind::Div => l.checked_div(r).map(Constant::Int),
                     BinOpKind::Rem => l.checked_rem(r).map(Constant::Int),
-                    BinOpKind::Shr => l.checked_shr(r.try_into().expect("shift too large")).map(Constant::Int),
-                    BinOpKind::Shl => l.checked_shl(r.try_into().expect("shift too large")).map(Constant::Int),
+                    BinOpKind::Shr => l.checked_shr(r.try_into().ok()?).map(Constant::Int),
+                    BinOpKind::Shl => l.checked_shl(r.try_into().ok()?).map(Constant::Int),
                     BinOpKind::BitXor => Some(Constant::Int(l ^ r)),
                     BinOpKind::BitOr => Some(Constant::Int(l | r)),
                     BinOpKind::BitAnd => Some(Constant::Int(l & r)),
diff --git a/src/tools/clippy/clippy_utils/src/diagnostics.rs b/src/tools/clippy/clippy_utils/src/diagnostics.rs
index 7f55db3b31f7..ad95369b9ef7 100644
--- a/src/tools/clippy/clippy_utils/src/diagnostics.rs
+++ b/src/tools/clippy/clippy_utils/src/diagnostics.rs
@@ -155,13 +155,7 @@ where
     });
 }
 
-pub fn span_lint_hir(
-    cx: &LateContext<'_>,
-    lint: &'static Lint,
-    hir_id: HirId,
-    sp: Span,
-    msg: &str,
-) {
+pub fn span_lint_hir(cx: &LateContext<'_>, lint: &'static Lint, hir_id: HirId, sp: Span, msg: &str) {
     cx.tcx.struct_span_lint_hir(lint, hir_id, sp, |diag| {
         let mut diag = diag.build(msg);
         docs_link(&mut diag, lint);
diff --git a/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs b/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
index 730724b95b96..91c9c382c236 100644
--- a/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
+++ b/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
@@ -45,12 +45,7 @@ impl ops::BitOrAssign for EagernessSuggestion {
 }
 
 /// Determine the eagerness of the given function call.
-fn fn_eagerness<'tcx>(
-    cx: &LateContext<'tcx>,
-    fn_id: DefId,
-    name: Symbol,
-    args: &'tcx [Expr<'_>],
-) -> EagernessSuggestion {
+fn fn_eagerness(cx: &LateContext<'_>, fn_id: DefId, name: Symbol, have_one_arg: bool) -> EagernessSuggestion {
     use EagernessSuggestion::{Eager, Lazy, NoChange};
     let name = name.as_str();
 
@@ -59,7 +54,7 @@ fn fn_eagerness<'tcx>(
         None => return Lazy,
     };
 
-    if (name.starts_with("as_") || name == "len" || name == "is_empty") && args.len() == 1 {
+    if (name.starts_with("as_") || name == "len" || name == "is_empty") && have_one_arg {
         if matches!(
             cx.tcx.crate_name(fn_id.krate),
             sym::std | sym::core | sym::alloc | sym::proc_macro
@@ -127,10 +122,11 @@ fn expr_eagerness<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> EagernessS
                     },
                     Res::Def(_, id) => match path {
                         QPath::Resolved(_, p) => {
-                            self.eagerness |= fn_eagerness(self.cx, id, p.segments.last().unwrap().ident.name, args);
+                            self.eagerness |=
+                                fn_eagerness(self.cx, id, p.segments.last().unwrap().ident.name, !args.is_empty());
                         },
                         QPath::TypeRelative(_, name) => {
-                            self.eagerness |= fn_eagerness(self.cx, id, name.ident.name, args);
+                            self.eagerness |= fn_eagerness(self.cx, id, name.ident.name, !args.is_empty());
                         },
                         QPath::LangItem(..) => self.eagerness = Lazy,
                     },
@@ -141,12 +137,12 @@ fn expr_eagerness<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> EagernessS
                     self.eagerness |= NoChange;
                     return;
                 },
-                ExprKind::MethodCall(name, args, _) => {
+                ExprKind::MethodCall(name, ..) => {
                     self.eagerness |= self
                         .cx
                         .typeck_results()
                         .type_dependent_def_id(e.hir_id)
-                        .map_or(Lazy, |id| fn_eagerness(self.cx, id, name.ident.name, args));
+                        .map_or(Lazy, |id| fn_eagerness(self.cx, id, name.ident.name, true));
                 },
                 ExprKind::Index(_, e) => {
                     let ty = self.cx.typeck_results().expr_ty_adjusted(e);
diff --git a/src/tools/clippy/clippy_utils/src/hir_utils.rs b/src/tools/clippy/clippy_utils/src/hir_utils.rs
index 1834e2a2de87..7212d9cd7445 100644
--- a/src/tools/clippy/clippy_utils/src/hir_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/hir_utils.rs
@@ -6,9 +6,9 @@ use rustc_data_structures::fx::FxHasher;
 use rustc_hir::def::Res;
 use rustc_hir::HirIdMap;
 use rustc_hir::{
-    ArrayLen, BinOpKind, Block, BodyId, Closure, Expr, ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, Guard,
-    HirId, InlineAsmOperand, Let, Lifetime, LifetimeName, ParamName, Pat, PatField, PatKind, Path, PathSegment, QPath,
-    Stmt, StmtKind, Ty, TyKind, TypeBinding,
+    ArrayLen, BinOpKind, BindingAnnotation, Block, BodyId, Closure, Expr, ExprField, ExprKind, FnRetTy, GenericArg,
+    GenericArgs, Guard, HirId, InlineAsmOperand, Let, Lifetime, LifetimeName, ParamName, Pat, PatField, PatKind, Path,
+    PathSegment, QPath, Stmt, StmtKind, Ty, TyKind, TypeBinding,
 };
 use rustc_lexer::{tokenize, TokenKind};
 use rustc_lint::LateContext;
@@ -201,8 +201,8 @@ impl HirEqInterExpr<'_, '_, '_> {
             self.inner.cx.tcx.typeck_body(right),
         ));
         let res = self.eq_expr(
-            &self.inner.cx.tcx.hir().body(left).value,
-            &self.inner.cx.tcx.hir().body(right).value,
+            self.inner.cx.tcx.hir().body(left).value,
+            self.inner.cx.tcx.hir().body(right).value,
         );
         self.inner.maybe_typeck_results = old_maybe_typeck_results;
         res
@@ -282,8 +282,14 @@ impl HirEqInterExpr<'_, '_, '_> {
                             && self.eq_expr(l.body, r.body)
                     })
             },
-            (&ExprKind::MethodCall(l_path, l_args, _), &ExprKind::MethodCall(r_path, r_args, _)) => {
-                self.inner.allow_side_effects && self.eq_path_segment(l_path, r_path) && self.eq_exprs(l_args, r_args)
+            (
+                &ExprKind::MethodCall(l_path, l_receiver, l_args, _),
+                &ExprKind::MethodCall(r_path, r_receiver, r_args, _),
+            ) => {
+                self.inner.allow_side_effects
+                    && self.eq_path_segment(l_path, r_path)
+                    && self.eq_expr(l_receiver, r_receiver)
+                    && self.eq_exprs(l_args, r_args)
             },
             (&ExprKind::Repeat(le, ll), &ExprKind::Repeat(re, rl)) => {
                 self.eq_expr(le, re) && self.eq_array_length(ll, rl)
@@ -643,7 +649,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
             }) => {
                 std::mem::discriminant(&capture_clause).hash(&mut self.s);
                 // closures inherit TypeckResults
-                self.hash_expr(&self.cx.tcx.hir().body(body).value);
+                self.hash_expr(self.cx.tcx.hir().body(body).value);
             },
             ExprKind::Field(e, ref f) => {
                 self.hash_expr(e);
@@ -743,8 +749,9 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
 
                 s.hash(&mut self.s);
             },
-            ExprKind::MethodCall(path, args, ref _fn_span) => {
+            ExprKind::MethodCall(path, receiver, args, ref _fn_span) => {
                 self.hash_name(path.ident.name);
+                self.hash_expr(receiver);
                 self.hash_exprs(args);
             },
             ExprKind::ConstBlock(ref l_id) => {
@@ -815,8 +822,9 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
     pub fn hash_pat(&mut self, pat: &Pat<'_>) {
         std::mem::discriminant(&pat.kind).hash(&mut self.s);
         match pat.kind {
-            PatKind::Binding(ann, _, _, pat) => {
-                std::mem::discriminant(&ann).hash(&mut self.s);
+            PatKind::Binding(BindingAnnotation(by_ref, mutability), _, _, pat) => {
+                std::mem::discriminant(&by_ref).hash(&mut self.s);
+                std::mem::discriminant(&mutability).hash(&mut self.s);
                 if let Some(pat) = pat {
                     self.hash_pat(pat);
                 }
@@ -921,7 +929,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
         }
     }
 
-    pub fn hash_lifetime(&mut self, lifetime: Lifetime) {
+    pub fn hash_lifetime(&mut self, lifetime: &Lifetime) {
         std::mem::discriminant(&lifetime.name).hash(&mut self.s);
         if let LifetimeName::Param(param_id, ref name) = lifetime.name {
             std::mem::discriminant(name).hash(&mut self.s);
@@ -979,8 +987,9 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 }
             },
             TyKind::Path(ref qpath) => self.hash_qpath(qpath),
-            TyKind::OpaqueDef(_, arg_list) => {
+            TyKind::OpaqueDef(_, arg_list, in_trait) => {
                 self.hash_generic_args(arg_list);
+                in_trait.hash(&mut self.s);
             },
             TyKind::TraitObject(_, lifetime, _) => {
                 self.hash_lifetime(*lifetime);
@@ -1002,7 +1011,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
     pub fn hash_body(&mut self, body_id: BodyId) {
         // swap out TypeckResults when hashing a body
         let old_maybe_typeck_results = self.maybe_typeck_results.replace(self.cx.tcx.typeck_body(body_id));
-        self.hash_expr(&self.cx.tcx.hir().body(body_id).value);
+        self.hash_expr(self.cx.tcx.hir().body(body_id).value);
         self.maybe_typeck_results = old_maybe_typeck_results;
     }
 
@@ -1010,7 +1019,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
         for arg in arg_list {
             match *arg {
                 GenericArg::Lifetime(l) => self.hash_lifetime(l),
-                GenericArg::Type(ref ty) => self.hash_ty(ty),
+                GenericArg::Type(ty) => self.hash_ty(ty),
                 GenericArg::Const(ref ca) => self.hash_body(ca.value.body),
                 GenericArg::Infer(ref inf) => self.hash_ty(&inf.to_ty()),
             }
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 313f1f1d9a6f..b1abd3b04c92 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -1,7 +1,6 @@
 #![feature(array_chunks)]
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
 #![feature(let_chains)]
 #![feature(lint_reasons)]
 #![feature(once_cell)]
@@ -28,6 +27,7 @@ extern crate rustc_infer;
 extern crate rustc_lexer;
 extern crate rustc_lint;
 extern crate rustc_middle;
+extern crate rustc_parse_format;
 extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_target;
@@ -77,7 +77,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_ID};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_hir::hir_id::{HirIdMap, HirIdSet};
 use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
 use rustc_hir::LangItem::{OptionNone, ResultErr, ResultOk};
@@ -87,6 +87,7 @@ use rustc_hir::{
     Mutability, Node, Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitItem, TraitItemKind,
     TraitRef, TyKind, UnOp,
 };
+use rustc_lexer::{tokenize, TokenKind};
 use rustc_lint::{LateContext, Level, Lint, LintContext};
 use rustc_middle::hir::place::PlaceBase;
 use rustc_middle::ty as rustc_ty;
@@ -104,6 +105,7 @@ use rustc_semver::RustcVersion;
 use rustc_session::Session;
 use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::source_map::original_sp;
+use rustc_span::source_map::SourceMap;
 use rustc_span::sym;
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{Span, DUMMY_SP};
@@ -189,7 +191,7 @@ pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<
     let hir = cx.tcx.hir();
     if_chain! {
         if let Some(Node::Pat(pat)) = hir.find(hir_id);
-        if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
+        if matches!(pat.kind, PatKind::Binding(BindingAnnotation::NONE, ..));
         let parent = hir.get_parent_node(hir_id);
         if let Some(Node::Local(local)) = hir.find(parent);
         then {
@@ -209,7 +211,7 @@ pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<
 /// }
 /// ```
 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
-    let parent_id = cx.tcx.hir().get_parent_item(id);
+    let parent_id = cx.tcx.hir().get_parent_item(id).def_id;
     match cx.tcx.hir().get_by_def_id(parent_id) {
         Node::Item(&Item {
             kind: ItemKind::Const(..) | ItemKind::Static(..),
@@ -334,7 +336,7 @@ pub fn qpath_generic_tys<'tcx>(qpath: &QPath<'tcx>) -> impl Iterator<Item = &'tc
         .map_or(&[][..], |a| a.args)
         .iter()
         .filter_map(|a| match a {
-            hir::GenericArg::Type(ty) => Some(ty),
+            hir::GenericArg::Type(ty) => Some(*ty),
             _ => None,
         })
 }
@@ -372,15 +374,19 @@ pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
 
 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
 ///
-/// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
+/// Please use `is_path_diagnostic_item` if the target is a diagnostic item.
 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
     path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, segments))
 }
 
-/// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
-/// diagnostic item.
-pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
-    path_def_id(cx, expr).map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
+/// If `maybe_path` is a path node which resolves to an item, resolves it to a `DefId` and checks if
+/// it matches the given diagnostic item.
+pub fn is_path_diagnostic_item<'tcx>(
+    cx: &LateContext<'_>,
+    maybe_path: &impl MaybePath<'tcx>,
+    diag_item: Symbol,
+) -> bool {
+    path_def_id(cx, maybe_path).map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
 }
 
 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
@@ -590,8 +596,8 @@ pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, def_id: LocalDefId) ->
     let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
     let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
     if_chain! {
-        if parent_impl != CRATE_DEF_ID;
-        if let hir::Node::Item(item) = cx.tcx.hir().get_by_def_id(parent_impl);
+        if parent_impl != hir::CRATE_OWNER_ID;
+        if let hir::Node::Item(item) = cx.tcx.hir().get_by_def_id(parent_impl.def_id);
         if let hir::ItemKind::Impl(impl_) = &item.kind;
         then {
             return impl_.of_trait.as_ref();
@@ -1024,26 +1030,26 @@ pub fn can_move_expr_to_closure<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'
     v.allow_closure.then_some(v.captures)
 }
 
+/// Arguments of a method: the receiver and all the additional arguments.
+pub type MethodArguments<'tcx> = Vec<(&'tcx Expr<'tcx>, &'tcx [Expr<'tcx>])>;
+
 /// Returns the method names and argument list of nested method call expressions that make up
 /// `expr`. method/span lists are sorted with the most recent call first.
-pub fn method_calls<'tcx>(
-    expr: &'tcx Expr<'tcx>,
-    max_depth: usize,
-) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
+pub fn method_calls<'tcx>(expr: &'tcx Expr<'tcx>, max_depth: usize) -> (Vec<Symbol>, MethodArguments<'tcx>, Vec<Span>) {
     let mut method_names = Vec::with_capacity(max_depth);
     let mut arg_lists = Vec::with_capacity(max_depth);
     let mut spans = Vec::with_capacity(max_depth);
 
     let mut current = expr;
     for _ in 0..max_depth {
-        if let ExprKind::MethodCall(path, args, _) = &current.kind {
-            if args.iter().any(|e| e.span.from_expansion()) {
+        if let ExprKind::MethodCall(path, receiver, args, _) = &current.kind {
+            if receiver.span.from_expansion() || args.iter().any(|e| e.span.from_expansion()) {
                 break;
             }
             method_names.push(path.ident.name);
-            arg_lists.push(&**args);
+            arg_lists.push((*receiver, &**args));
             spans.push(path.ident.span);
-            current = &args[0];
+            current = receiver;
         } else {
             break;
         }
@@ -1058,18 +1064,18 @@ pub fn method_calls<'tcx>(
 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
 /// containing the `Expr`s for
 /// `.bar()` and `.baz()`
-pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
+pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<(&'a Expr<'a>, &'a [Expr<'a>])>> {
     let mut current = expr;
     let mut matched = Vec::with_capacity(methods.len());
     for method_name in methods.iter().rev() {
         // method chains are stored last -> first
-        if let ExprKind::MethodCall(path, args, _) = current.kind {
+        if let ExprKind::MethodCall(path, receiver, args, _) = current.kind {
             if path.ident.name.as_str() == *method_name {
-                if args.iter().any(|e| e.span.from_expansion()) {
+                if receiver.span.from_expansion() || args.iter().any(|e| e.span.from_expansion()) {
                     return None;
                 }
-                matched.push(args); // build up `matched` backwards
-                current = &args[0]; // go to parent expression
+                matched.push((receiver, args)); // build up `matched` backwards
+                current = receiver; // go to parent expression
             } else {
                 return None;
             }
@@ -1097,7 +1103,7 @@ pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
 
 /// Gets the name of the item the expression is in, if available.
 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
-    let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
+    let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id).def_id;
     match cx.tcx.hir().find_by_def_id(parent_id) {
         Some(
             Node::Item(Item { ident, .. })
@@ -1114,7 +1120,7 @@ pub struct ContainsName {
 }
 
 impl<'tcx> Visitor<'tcx> for ContainsName {
-    fn visit_name(&mut self, _: Span, name: Symbol) {
+    fn visit_name(&mut self, name: Symbol) {
         if self.name == name {
             self.result = true;
         }
@@ -1232,8 +1238,10 @@ pub fn get_enclosing_loop_or_multi_call_closure<'tcx>(
                                     ty_is_fn_once_param(cx.tcx, ty.skip_binder(), predicates).then_some(())
                                 })
                             },
-                            ExprKind::MethodCall(_, args, _) => {
-                                let i = args.iter().position(|arg| arg.hir_id == id)?;
+                            ExprKind::MethodCall(_, receiver, args, _) => {
+                                let i = std::iter::once(receiver)
+                                    .chain(args.iter())
+                                    .position(|arg| arg.hir_id == id)?;
                                 let id = cx.typeck_results().type_dependent_def_id(e.hir_id)?;
                                 let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i];
                                 ty_is_fn_once_param(cx.tcx, ty, cx.tcx.param_env(id).caller_bounds()).then_some(())
@@ -1543,7 +1551,8 @@ pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl It
 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
     fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
         if_chain! {
-            if let PatKind::TupleStruct(ref path, pat, None) = arm.pat.kind;
+            if let PatKind::TupleStruct(ref path, pat, ddpos) = arm.pat.kind;
+            if ddpos.as_opt_usize().is_none();
             if is_lang_ctor(cx, path, ResultOk);
             if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
             if path_to_local_id(arm.body, hir_id);
@@ -1638,7 +1647,7 @@ pub fn any_parent_has_attr(tcx: TyCtxt<'_>, node: HirId, symbol: Symbol) -> bool
             return true;
         }
         prev_enclosing_node = Some(enclosing_node);
-        enclosing_node = map.local_def_id_to_hir_id(map.get_parent_item(enclosing_node));
+        enclosing_node = map.get_parent_item(enclosing_node).into();
     }
 
     false
@@ -1805,7 +1814,7 @@ pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool
             }
         };
 
-        let mut expr = &func.value;
+        let mut expr = func.value;
         loop {
             match expr.kind {
                 #[rustfmt::skip]
@@ -2274,6 +2283,18 @@ pub fn walk_to_expr_usage<'tcx, T>(
     None
 }
 
+/// Checks whether a given span has any comment token
+/// This checks for all types of comment: line "//", block "/**", doc "///" "//!"
+pub fn span_contains_comment(sm: &SourceMap, span: Span) -> bool {
+    let Ok(snippet) = sm.span_to_snippet(span) else { return false };
+    return tokenize(&snippet).any(|token| {
+        matches!(
+            token.kind,
+            TokenKind::BlockComment { .. } | TokenKind::LineComment { .. }
+        )
+    });
+}
+
 macro_rules! op_utils {
     ($($name:ident $assign:ident)*) => {
         /// Binary operation traits like `LangItem::Add`
diff --git a/src/tools/clippy/clippy_utils/src/macros.rs b/src/tools/clippy/clippy_utils/src/macros.rs
index a268e339bb13..a1808c097200 100644
--- a/src/tools/clippy/clippy_utils/src/macros.rs
+++ b/src/tools/clippy/clippy_utils/src/macros.rs
@@ -1,16 +1,21 @@
 #![allow(clippy::similar_names)] // `expr` and `expn`
 
+use crate::is_path_diagnostic_item;
+use crate::source::snippet_opt;
 use crate::visitors::expr_visitor_no_bodies;
 
 use arrayvec::ArrayVec;
-use if_chain::if_chain;
+use itertools::{izip, Either, Itertools};
 use rustc_ast::ast::LitKind;
-use rustc_hir::intravisit::Visitor;
-use rustc_hir::{self as hir, Expr, ExprKind, HirId, Node, QPath};
+use rustc_hir::intravisit::{walk_expr, Visitor};
+use rustc_hir::{self as hir, Expr, ExprField, ExprKind, HirId, Node, QPath};
+use rustc_lexer::unescape::unescape_literal;
+use rustc_lexer::{tokenize, unescape, LiteralKind, TokenKind};
 use rustc_lint::LateContext;
+use rustc_parse_format::{self as rpf, Alignment};
 use rustc_span::def_id::DefId;
 use rustc_span::hygiene::{self, MacroKind, SyntaxContext};
-use rustc_span::{sym, ExpnData, ExpnId, ExpnKind, Span, Symbol};
+use rustc_span::{sym, BytePos, ExpnData, ExpnId, ExpnKind, Pos, Span, SpanData, Symbol};
 use std::ops::ControlFlow;
 
 const FORMAT_MACRO_DIAG_ITEMS: &[Symbol] = &[
@@ -332,121 +337,487 @@ fn is_assert_arg(cx: &LateContext<'_>, expr: &Expr<'_>, assert_expn: ExpnId) ->
     }
 }
 
-/// A parsed `format_args!` expansion
+/// The format string doesn't exist in the HIR, so we reassemble it from source code
 #[derive(Debug)]
-pub struct FormatArgsExpn<'tcx> {
-    /// Span of the first argument, the format string
-    pub format_string_span: Span,
-    /// The format string split by formatted args like `{..}`
-    pub format_string_parts: Vec<Symbol>,
-    /// Values passed after the format string
-    pub value_args: Vec<&'tcx Expr<'tcx>>,
-    /// Each element is a `value_args` index and a formatting trait (e.g. `sym::Debug`)
-    pub formatters: Vec<(usize, Symbol)>,
-    /// List of `fmt::v1::Argument { .. }` expressions. If this is empty,
-    /// then `formatters` represents the format args (`{..}`).
-    /// If this is non-empty, it represents the format args, and the `position`
-    /// parameters within the struct expressions are indexes of `formatters`.
-    pub specs: Vec<&'tcx Expr<'tcx>>,
+pub struct FormatString {
+    /// Span of the whole format string literal, including `[r#]"`.
+    pub span: Span,
+    /// Snippet of the whole format string literal, including `[r#]"`.
+    pub snippet: String,
+    /// If the string is raw `r"..."`/`r#""#`, how many `#`s does it have on each side.
+    pub style: Option<usize>,
+    /// The unescaped value of the format string, e.g. `"val – {}"` for the literal
+    /// `"val \u{2013} {}"`.
+    pub unescaped: String,
+    /// The format string split by format args like `{..}`.
+    pub parts: Vec<Symbol>,
 }
 
-impl<'tcx> FormatArgsExpn<'tcx> {
-    /// Parses an expanded `format_args!` or `format_args_nl!` invocation
-    pub fn parse(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<Self> {
-        macro_backtrace(expr.span).find(|macro_call| {
-            matches!(
-                cx.tcx.item_name(macro_call.def_id),
-                sym::const_format_args | sym::format_args | sym::format_args_nl
-            )
-        })?;
-        let mut format_string_span: Option<Span> = None;
-        let mut format_string_parts: Vec<Symbol> = Vec::new();
-        let mut value_args: Vec<&Expr<'_>> = Vec::new();
-        let mut formatters: Vec<(usize, Symbol)> = Vec::new();
-        let mut specs: Vec<&Expr<'_>> = Vec::new();
-        expr_visitor_no_bodies(|e| {
-            // if we're still inside of the macro definition...
-            if e.span.ctxt() == expr.span.ctxt() {
-                // ArgumentV1::new_<format_trait>(<value>)
-                if_chain! {
-                    if let ExprKind::Call(callee, [val]) = e.kind;
-                    if let ExprKind::Path(QPath::TypeRelative(ty, seg)) = callee.kind;
-                    if let hir::TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
-                    if path.segments.last().unwrap().ident.name == sym::ArgumentV1;
-                    if seg.ident.name.as_str().starts_with("new_");
-                    then {
-                        let val_idx = if_chain! {
-                            if val.span.ctxt() == expr.span.ctxt();
-                            if let ExprKind::Field(_, field) = val.kind;
-                            if let Ok(idx) = field.name.as_str().parse();
-                            then {
-                                // tuple index
-                                idx
-                            } else {
-                                // assume the value expression is passed directly
-                                formatters.len()
-                            }
-                        };
-                        let fmt_trait = match seg.ident.name.as_str() {
-                            "new_display" => "Display",
-                            "new_debug" => "Debug",
-                            "new_lower_exp" => "LowerExp",
-                            "new_upper_exp" => "UpperExp",
-                            "new_octal" => "Octal",
-                            "new_pointer" => "Pointer",
-                            "new_binary" => "Binary",
-                            "new_lower_hex" => "LowerHex",
-                            "new_upper_hex" => "UpperHex",
-                            _ => unreachable!(),
-                        };
-                        formatters.push((val_idx, Symbol::intern(fmt_trait)));
-                    }
+impl FormatString {
+    fn new(cx: &LateContext<'_>, pieces: &Expr<'_>) -> Option<Self> {
+        // format_args!(r"a {} b \", 1);
+        //
+        // expands to
+        //
+        // ::core::fmt::Arguments::new_v1(&["a ", " b \\"],
+        //      &[::core::fmt::ArgumentV1::new_display(&1)]);
+        //
+        // where `pieces` is the expression `&["a ", " b \\"]`. It has the span of `r"a {} b \"`
+        let span = pieces.span;
+        let snippet = snippet_opt(cx, span)?;
+
+        let (inner, style) = match tokenize(&snippet).next()?.kind {
+            TokenKind::Literal { kind, .. } => {
+                let style = match kind {
+                    LiteralKind::Str { .. } => None,
+                    LiteralKind::RawStr { n_hashes: Some(n), .. } => Some(n.into()),
+                    _ => return None,
+                };
+
+                let start = style.map_or(1, |n| 2 + n);
+                let end = snippet.len() - style.map_or(1, |n| 1 + n);
+
+                (&snippet[start..end], style)
+            },
+            _ => return None,
+        };
+
+        let mode = if style.is_some() {
+            unescape::Mode::RawStr
+        } else {
+            unescape::Mode::Str
+        };
+
+        let mut unescaped = String::with_capacity(inner.len());
+        unescape_literal(inner, mode, &mut |_, ch| match ch {
+            Ok(ch) => unescaped.push(ch),
+            Err(e) if !e.is_fatal() => (),
+            Err(e) => panic!("{:?}", e),
+        });
+
+        let mut parts = Vec::new();
+        expr_visitor_no_bodies(|expr| {
+            if let ExprKind::Lit(lit) = &expr.kind {
+                if let LitKind::Str(symbol, _) = lit.node {
+                    parts.push(symbol);
                 }
-                if let ExprKind::Struct(QPath::Resolved(_, path), ..) = e.kind {
-                    if path.segments.last().unwrap().ident.name == sym::Argument {
-                        specs.push(e);
-                    }
-                }
-                // walk through the macro expansion
-                return true;
             }
-            // assume that the first expr with a differing context represents
-            // (and has the span of) the format string
-            if format_string_span.is_none() {
-                format_string_span = Some(e.span);
-                let span = e.span;
-                // walk the expr and collect string literals which are format string parts
-                expr_visitor_no_bodies(|e| {
-                    if e.span.ctxt() != span.ctxt() {
-                        // defensive check, probably doesn't happen
-                        return false;
-                    }
-                    if let ExprKind::Lit(lit) = &e.kind {
-                        if let LitKind::Str(symbol, _s) = lit.node {
-                            format_string_parts.push(symbol);
-                        }
-                    }
-                    true
-                })
-                .visit_expr(e);
-            } else {
-                // assume that any further exprs with a differing context are value args
-                value_args.push(e);
-            }
-            // don't walk anything not from the macro expansion (e.a. inputs)
-            false
+
+            true
         })
-        .visit_expr(expr);
-        Some(FormatArgsExpn {
-            format_string_span: format_string_span?,
-            format_string_parts,
+        .visit_expr(pieces);
+
+        Some(Self {
+            span,
+            snippet,
+            style,
+            unescaped,
+            parts,
+        })
+    }
+}
+
+struct FormatArgsValues<'tcx> {
+    /// See `FormatArgsExpn::value_args`
+    value_args: Vec<&'tcx Expr<'tcx>>,
+    /// Maps an `rt::v1::Argument::position` or an `rt::v1::Count::Param` to its index in
+    /// `value_args`
+    pos_to_value_index: Vec<usize>,
+    /// Used to check if a value is declared inline & to resolve `InnerSpan`s.
+    format_string_span: SpanData,
+}
+
+impl<'tcx> FormatArgsValues<'tcx> {
+    fn new(args: &'tcx Expr<'tcx>, format_string_span: SpanData) -> Self {
+        let mut pos_to_value_index = Vec::new();
+        let mut value_args = Vec::new();
+        expr_visitor_no_bodies(|expr| {
+            if expr.span.ctxt() == args.span.ctxt() {
+                // ArgumentV1::new_<format_trait>(<val>)
+                // ArgumentV1::from_usize(<val>)
+                if let ExprKind::Call(callee, [val]) = expr.kind
+                    && let ExprKind::Path(QPath::TypeRelative(ty, _)) = callee.kind
+                    && let hir::TyKind::Path(QPath::Resolved(_, path)) = ty.kind
+                    && path.segments.last().unwrap().ident.name == sym::ArgumentV1
+                {
+                    let val_idx = if val.span.ctxt() == expr.span.ctxt()
+                        && let ExprKind::Field(_, field) = val.kind
+                        && let Ok(idx) = field.name.as_str().parse()
+                    {
+                        // tuple index
+                        idx
+                    } else {
+                        // assume the value expression is passed directly
+                        pos_to_value_index.len()
+                    };
+
+                    pos_to_value_index.push(val_idx);
+                }
+
+                true
+            } else {
+                // assume that any expr with a differing span is a value
+                value_args.push(expr);
+
+                false
+            }
+        })
+        .visit_expr(args);
+
+        Self {
             value_args,
-            formatters,
-            specs,
+            pos_to_value_index,
+            format_string_span,
+        }
+    }
+}
+
+/// The positions of a format argument's value, precision and width
+///
+/// A position is an index into the second argument of `Arguments::new_v1[_formatted]`
+#[derive(Debug, Default, Copy, Clone)]
+struct ParamPosition {
+    /// The position stored in `rt::v1::Argument::position`.
+    value: usize,
+    /// The position stored in `rt::v1::FormatSpec::width` if it is a `Count::Param`.
+    width: Option<usize>,
+    /// The position stored in `rt::v1::FormatSpec::precision` if it is a `Count::Param`.
+    precision: Option<usize>,
+}
+
+impl<'tcx> Visitor<'tcx> for ParamPosition {
+    fn visit_expr_field(&mut self, field: &'tcx ExprField<'tcx>) {
+        fn parse_count(expr: &Expr<'_>) -> Option<usize> {
+            // ::core::fmt::rt::v1::Count::Param(1usize),
+            if let ExprKind::Call(ctor, [val]) = expr.kind
+                && let ExprKind::Path(QPath::Resolved(_, path)) = ctor.kind
+                && path.segments.last()?.ident.name == sym::Param
+                && let ExprKind::Lit(lit) = &val.kind
+                && let LitKind::Int(pos, _) = lit.node
+            {
+                Some(pos as usize)
+            } else {
+                None
+            }
+        }
+
+        match field.ident.name {
+            sym::position => {
+                if let ExprKind::Lit(lit) = &field.expr.kind
+                    && let LitKind::Int(pos, _) = lit.node
+                {
+                    self.value = pos as usize;
+                }
+            },
+            sym::precision => {
+                self.precision = parse_count(field.expr);
+            },
+            sym::width => {
+                self.width = parse_count(field.expr);
+            },
+            _ => walk_expr(self, field.expr),
+        }
+    }
+}
+
+/// Parses the `fmt` arg of `Arguments::new_v1_formatted(pieces, args, fmt, _)`
+fn parse_rt_fmt<'tcx>(fmt_arg: &'tcx Expr<'tcx>) -> Option<impl Iterator<Item = ParamPosition> + 'tcx> {
+    if let ExprKind::AddrOf(.., array) = fmt_arg.kind
+        && let ExprKind::Array(specs) = array.kind
+    {
+        Some(specs.iter().map(|spec| {
+            let mut position = ParamPosition::default();
+            position.visit_expr(spec);
+            position
+        }))
+    } else {
+        None
+    }
+}
+
+/// `Span::from_inner`, but for `rustc_parse_format`'s `InnerSpan`
+fn span_from_inner(base: SpanData, inner: rpf::InnerSpan) -> Span {
+    Span::new(
+        base.lo + BytePos::from_usize(inner.start),
+        base.lo + BytePos::from_usize(inner.end),
+        base.ctxt,
+        base.parent,
+    )
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum FormatParamKind {
+    /// An implicit parameter , such as `{}` or `{:?}`.
+    Implicit,
+    /// A parameter with an explicit number, or an asterisk precision. e.g. `{1}`, `{0:?}`,
+    /// `{:.0$}` or `{:.*}`.
+    Numbered,
+    /// A named parameter with a named `value_arg`, such as the `x` in `format!("{x}", x = 1)`.
+    Named(Symbol),
+    /// An implicit named parameter, such as the `y` in `format!("{y}")`.
+    NamedInline(Symbol),
+}
+
+/// A `FormatParam` is any place in a `FormatArgument` that refers to a supplied value, e.g.
+///
+/// ```
+/// let precision = 2;
+/// format!("{:.precision$}", 0.1234);
+/// ```
+///
+/// has two `FormatParam`s, a [`FormatParamKind::Implicit`] `.kind` with a `.value` of `0.1234`
+/// and a [`FormatParamKind::NamedInline("precision")`] `.kind` with a `.value` of `2`
+#[derive(Debug, Copy, Clone)]
+pub struct FormatParam<'tcx> {
+    /// The expression this parameter refers to.
+    pub value: &'tcx Expr<'tcx>,
+    /// How this parameter refers to its `value`.
+    pub kind: FormatParamKind,
+    /// Span of the parameter, may be zero width. Includes the whitespace of implicit parameters.
+    ///
+    /// ```text
+    /// format!("{}, {  }, {0}, {name}", ...);
+    ///          ^    ~~    ~    ~~~~
+    /// ```
+    pub span: Span,
+}
+
+impl<'tcx> FormatParam<'tcx> {
+    fn new(
+        mut kind: FormatParamKind,
+        position: usize,
+        inner: rpf::InnerSpan,
+        values: &FormatArgsValues<'tcx>,
+    ) -> Option<Self> {
+        let value_index = *values.pos_to_value_index.get(position)?;
+        let value = *values.value_args.get(value_index)?;
+        let span = span_from_inner(values.format_string_span, inner);
+
+        // if a param is declared inline, e.g. `format!("{x}")`, the generated expr's span points
+        // into the format string
+        if let FormatParamKind::Named(name) = kind && values.format_string_span.contains(value.span.data()) {
+            kind = FormatParamKind::NamedInline(name);
+        }
+
+        Some(Self { value, kind, span })
+    }
+}
+
+/// Used by [width](https://doc.rust-lang.org/std/fmt/#width) and
+/// [precision](https://doc.rust-lang.org/std/fmt/#precision) specifiers.
+#[derive(Debug, Copy, Clone)]
+pub enum Count<'tcx> {
+    /// Specified with a literal number, stores the value.
+    Is(usize, Span),
+    /// Specified using `$` and `*` syntaxes. The `*` format is still considered to be
+    /// `FormatParamKind::Numbered`.
+    Param(FormatParam<'tcx>),
+    /// Not specified.
+    Implied,
+}
+
+impl<'tcx> Count<'tcx> {
+    fn new(
+        count: rpf::Count<'_>,
+        position: Option<usize>,
+        inner: Option<rpf::InnerSpan>,
+        values: &FormatArgsValues<'tcx>,
+    ) -> Option<Self> {
+        Some(match count {
+            rpf::Count::CountIs(val) => Self::Is(val, span_from_inner(values.format_string_span, inner?)),
+            rpf::Count::CountIsName(name, span) => Self::Param(FormatParam::new(
+                FormatParamKind::Named(Symbol::intern(name)),
+                position?,
+                span,
+                values,
+            )?),
+            rpf::Count::CountIsParam(_) | rpf::Count::CountIsStar(_) => {
+                Self::Param(FormatParam::new(FormatParamKind::Numbered, position?, inner?, values)?)
+            },
+            rpf::Count::CountImplied => Self::Implied,
         })
     }
 
-    /// Finds a nested call to `format_args!` within a `format!`-like macro call
+    pub fn is_implied(self) -> bool {
+        matches!(self, Count::Implied)
+    }
+
+    pub fn param(self) -> Option<FormatParam<'tcx>> {
+        match self {
+            Count::Param(param) => Some(param),
+            _ => None,
+        }
+    }
+}
+
+/// Specification for the formatting of an argument in the format string. See
+/// <https://doc.rust-lang.org/std/fmt/index.html#formatting-parameters> for the precise meanings.
+#[derive(Debug)]
+pub struct FormatSpec<'tcx> {
+    /// Optionally specified character to fill alignment with.
+    pub fill: Option<char>,
+    /// Optionally specified alignment.
+    pub align: Alignment,
+    /// Packed version of various flags provided, see [`rustc_parse_format::Flag`].
+    pub flags: u32,
+    /// Represents either the maximum width or the integer precision.
+    pub precision: Count<'tcx>,
+    /// The minimum width, will be padded according to `width`/`align`
+    pub width: Count<'tcx>,
+    /// The formatting trait used by the argument, e.g. `sym::Display` for `{}`, `sym::Debug` for
+    /// `{:?}`.
+    pub r#trait: Symbol,
+    pub trait_span: Option<Span>,
+}
+
+impl<'tcx> FormatSpec<'tcx> {
+    fn new(spec: rpf::FormatSpec<'_>, positions: ParamPosition, values: &FormatArgsValues<'tcx>) -> Option<Self> {
+        Some(Self {
+            fill: spec.fill,
+            align: spec.align,
+            flags: spec.flags,
+            precision: Count::new(spec.precision, positions.precision, spec.precision_span, values)?,
+            width: Count::new(spec.width, positions.width, spec.width_span, values)?,
+            r#trait: match spec.ty {
+                "" => sym::Display,
+                "?" => sym::Debug,
+                "o" => sym!(Octal),
+                "x" => sym!(LowerHex),
+                "X" => sym!(UpperHex),
+                "p" => sym::Pointer,
+                "b" => sym!(Binary),
+                "e" => sym!(LowerExp),
+                "E" => sym!(UpperExp),
+                _ => return None,
+            },
+            trait_span: spec
+                .ty_span
+                .map(|span| span_from_inner(values.format_string_span, span)),
+        })
+    }
+
+    /// Returns true if this format spec is unchanged from the default. e.g. returns true for `{}`,
+    /// `{foo}` and `{2}`, but false for `{:?}`, `{foo:5}` and `{3:.5}`
+    pub fn is_default(&self) -> bool {
+        self.r#trait == sym::Display
+            && self.width.is_implied()
+            && self.precision.is_implied()
+            && self.align == Alignment::AlignUnknown
+            && self.flags == 0
+    }
+}
+
+/// A format argument, such as `{}`, `{foo:?}`.
+#[derive(Debug)]
+pub struct FormatArg<'tcx> {
+    /// The parameter the argument refers to.
+    pub param: FormatParam<'tcx>,
+    /// How to format `param`.
+    pub format: FormatSpec<'tcx>,
+    /// span of the whole argument, `{..}`.
+    pub span: Span,
+}
+
+/// A parsed `format_args!` expansion.
+#[derive(Debug)]
+pub struct FormatArgsExpn<'tcx> {
+    /// The format string literal.
+    pub format_string: FormatString,
+    // The format arguments, such as `{:?}`.
+    pub args: Vec<FormatArg<'tcx>>,
+    /// Has an added newline due to `println!()`/`writeln!()`/etc. The last format string part will
+    /// include this added newline.
+    pub newline: bool,
+    /// Values passed after the format string and implicit captures. `[1, z + 2, x]` for
+    /// `format!("{x} {} {y}", 1, z + 2)`.
+    value_args: Vec<&'tcx Expr<'tcx>>,
+}
+
+impl<'tcx> FormatArgsExpn<'tcx> {
+    pub fn parse(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<Self> {
+        let macro_name = macro_backtrace(expr.span)
+            .map(|macro_call| cx.tcx.item_name(macro_call.def_id))
+            .find(|&name| matches!(name, sym::const_format_args | sym::format_args | sym::format_args_nl))?;
+        let newline = macro_name == sym::format_args_nl;
+
+        // ::core::fmt::Arguments::new_v1(pieces, args)
+        // ::core::fmt::Arguments::new_v1_formatted(pieces, args, fmt, _unsafe_arg)
+        if let ExprKind::Call(callee, [pieces, args, rest @ ..]) = expr.kind
+            && let ExprKind::Path(QPath::TypeRelative(ty, seg)) = callee.kind
+            && is_path_diagnostic_item(cx, ty, sym::Arguments)
+            && matches!(seg.ident.as_str(), "new_v1" | "new_v1_formatted")
+        {
+            let format_string = FormatString::new(cx, pieces)?;
+
+            let mut parser = rpf::Parser::new(
+                &format_string.unescaped,
+                format_string.style,
+                Some(format_string.snippet.clone()),
+                // `format_string.unescaped` does not contain the appended newline
+                false,
+                rpf::ParseMode::Format,
+            );
+
+            let parsed_args = parser
+                .by_ref()
+                .filter_map(|piece| match piece {
+                    rpf::Piece::NextArgument(a) => Some(a),
+                    rpf::Piece::String(_) => None,
+                })
+                .collect_vec();
+            if !parser.errors.is_empty() {
+                return None;
+            }
+
+            let positions = if let Some(fmt_arg) = rest.first() {
+                // If the argument contains format specs, `new_v1_formatted(_, _, fmt, _)`, parse
+                // them.
+
+                Either::Left(parse_rt_fmt(fmt_arg)?)
+            } else {
+                // If no format specs are given, the positions are in the given order and there are
+                // no `precision`/`width`s to consider.
+
+                Either::Right((0..).map(|n| ParamPosition {
+                    value: n,
+                    width: None,
+                    precision: None,
+                }))
+            };
+
+            let values = FormatArgsValues::new(args, format_string.span.data());
+
+            let args = izip!(positions, parsed_args, parser.arg_places)
+                .map(|(position, parsed_arg, arg_span)| {
+                    Some(FormatArg {
+                        param: FormatParam::new(
+                            match parsed_arg.position {
+                                rpf::Position::ArgumentImplicitlyIs(_) => FormatParamKind::Implicit,
+                                rpf::Position::ArgumentIs(_) => FormatParamKind::Numbered,
+                                // NamedInline is handled by `FormatParam::new()`
+                                rpf::Position::ArgumentNamed(name) => FormatParamKind::Named(Symbol::intern(name)),
+                            },
+                            position.value,
+                            parsed_arg.position_span,
+                            &values,
+                        )?,
+                        format: FormatSpec::new(parsed_arg.format, position, &values)?,
+                        span: span_from_inner(values.format_string_span, arg_span),
+                    })
+                })
+                .collect::<Option<Vec<_>>>()?;
+
+            Some(Self {
+                format_string,
+                args,
+                value_args: values.value_args,
+                newline,
+            })
+        } else {
+            None
+        }
+    }
+
     pub fn find_nested(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expn_id: ExpnId) -> Option<Self> {
         let mut format_args = None;
         expr_visitor_no_bodies(|e| {
@@ -466,88 +837,23 @@ impl<'tcx> FormatArgsExpn<'tcx> {
         format_args
     }
 
-    /// Returns a vector of `FormatArgsArg`.
-    pub fn args(&self) -> Option<Vec<FormatArgsArg<'tcx>>> {
-        if self.specs.is_empty() {
-            let args = std::iter::zip(&self.value_args, &self.formatters)
-                .map(|(value, &(_, format_trait))| FormatArgsArg {
-                    value,
-                    format_trait,
-                    spec: None,
-                })
-                .collect();
-            return Some(args);
-        }
-        self.specs
-            .iter()
-            .map(|spec| {
-                if_chain! {
-                    // struct `core::fmt::rt::v1::Argument`
-                    if let ExprKind::Struct(_, fields, _) = spec.kind;
-                    if let Some(position_field) = fields.iter().find(|f| f.ident.name == sym::position);
-                    if let ExprKind::Lit(lit) = &position_field.expr.kind;
-                    if let LitKind::Int(position, _) = lit.node;
-                    if let Ok(i) = usize::try_from(position);
-                    if let Some(&(j, format_trait)) = self.formatters.get(i);
-                    then {
-                        Some(FormatArgsArg {
-                            value: self.value_args[j],
-                            format_trait,
-                            spec: Some(spec),
-                        })
-                    } else {
-                        None
-                    }
-                }
-            })
-            .collect()
-    }
-
     /// Source callsite span of all inputs
     pub fn inputs_span(&self) -> Span {
         match *self.value_args {
-            [] => self.format_string_span,
+            [] => self.format_string.span,
             [.., last] => self
-                .format_string_span
-                .to(hygiene::walk_chain(last.span, self.format_string_span.ctxt())),
+                .format_string
+                .span
+                .to(hygiene::walk_chain(last.span, self.format_string.span.ctxt())),
         }
     }
-}
 
-/// Type representing a `FormatArgsExpn`'s format arguments
-pub struct FormatArgsArg<'tcx> {
-    /// An element of `value_args` according to `position`
-    pub value: &'tcx Expr<'tcx>,
-    /// An element of `args` according to `position`
-    pub format_trait: Symbol,
-    /// An element of `specs`
-    pub spec: Option<&'tcx Expr<'tcx>>,
-}
-
-impl<'tcx> FormatArgsArg<'tcx> {
-    /// Returns true if any formatting parameters are used that would have an effect on strings,
-    /// like `{:+2}` instead of just `{}`.
-    pub fn has_string_formatting(&self) -> bool {
-        self.spec.map_or(false, |spec| {
-            // `!` because these conditions check that `self` is unformatted.
-            !if_chain! {
-                // struct `core::fmt::rt::v1::Argument`
-                if let ExprKind::Struct(_, fields, _) = spec.kind;
-                if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym::format);
-                // struct `core::fmt::rt::v1::FormatSpec`
-                if let ExprKind::Struct(_, subfields, _) = format_field.expr.kind;
-                if subfields.iter().all(|field| match field.ident.name {
-                    sym::precision | sym::width => match field.expr.kind {
-                        ExprKind::Path(QPath::Resolved(_, path)) => {
-                            path.segments.last().unwrap().ident.name == sym::Implied
-                        }
-                        _ => false,
-                    }
-                    _ => true,
-                });
-                then { true } else { false }
-            }
-        })
+    /// Iterator of all format params, both values and those referenced by `width`/`precision`s.
+    pub fn params(&'tcx self) -> impl Iterator<Item = FormatParam<'tcx>> {
+        self.args
+            .iter()
+            .flat_map(|arg| [Some(arg.param), arg.format.precision.param(), arg.format.width.param()])
+            .flatten()
     }
 }
 
diff --git a/src/tools/clippy/clippy_utils/src/msrvs.rs b/src/tools/clippy/clippy_utils/src/msrvs.rs
index 9e238c6f1ac0..62020e21c815 100644
--- a/src/tools/clippy/clippy_utils/src/msrvs.rs
+++ b/src/tools/clippy/clippy_utils/src/msrvs.rs
@@ -13,7 +13,7 @@ macro_rules! msrv_aliases {
 // names may refer to stabilized feature flags or library items
 msrv_aliases! {
     1,62,0 { BOOL_THEN_SOME }
-    1,53,0 { OR_PATTERNS, MANUAL_BITS, BTREE_MAP_RETAIN, BTREE_SET_RETAIN }
+    1,53,0 { OR_PATTERNS, MANUAL_BITS, BTREE_MAP_RETAIN, BTREE_SET_RETAIN, ARRAY_INTO_ITERATOR }
     1,52,0 { STR_SPLIT_ONCE, REM_EUCLID_CONST }
     1,51,0 { BORROW_AS_PTR, UNSIGNED_ABS }
     1,50,0 { BOOL_THEN }
@@ -32,8 +32,8 @@ msrv_aliases! {
     1,30,0 { ITERATOR_FIND_MAP, TOOL_ATTRIBUTES }
     1,28,0 { FROM_BOOL }
     1,26,0 { RANGE_INCLUSIVE, STRING_RETAIN }
+    1,24,0 { IS_ASCII_DIGIT }
     1,18,0 { HASH_MAP_RETAIN, HASH_SET_RETAIN }
     1,17,0 { FIELD_INIT_SHORTHAND, STATIC_IN_CONST, EXPECT_ERR }
     1,16,0 { STR_REPEAT }
-    1,24,0 { IS_ASCII_DIGIT }
 }
diff --git a/src/tools/clippy/clippy_utils/src/paths.rs b/src/tools/clippy/clippy_utils/src/paths.rs
index 8d697a301c44..07170e2df12a 100644
--- a/src/tools/clippy/clippy_utils/src/paths.rs
+++ b/src/tools/clippy/clippy_utils/src/paths.rs
@@ -66,12 +66,9 @@ pub const INDEX_MUT: [&str; 3] = ["core", "ops", "IndexMut"];
 pub const INSERT_STR: [&str; 4] = ["alloc", "string", "String", "insert_str"];
 pub const IO_READ: [&str; 3] = ["std", "io", "Read"];
 pub const IO_WRITE: [&str; 3] = ["std", "io", "Write"];
-pub const IPADDR_V4: [&str; 5] = ["std", "net", "ip", "IpAddr", "V4"];
-pub const IPADDR_V6: [&str; 5] = ["std", "net", "ip", "IpAddr", "V6"];
 pub const ITER_COUNT: [&str; 6] = ["core", "iter", "traits", "iterator", "Iterator", "count"];
 pub const ITER_EMPTY: [&str; 5] = ["core", "iter", "sources", "empty", "Empty"];
 pub const ITER_REPEAT: [&str; 5] = ["core", "iter", "sources", "repeat", "repeat"];
-#[expect(clippy::invalid_paths)] // internal lints do not know about all external crates
 pub const ITERTOOLS_NEXT_TUPLE: [&str; 3] = ["itertools", "Itertools", "next_tuple"];
 #[cfg(feature = "internal")]
 pub const KW_MODULE: [&str; 3] = ["rustc_span", "symbol", "kw"];
@@ -96,6 +93,7 @@ pub const PARKING_LOT_RWLOCK_READ_GUARD: [&str; 3] = ["lock_api", "rwlock", "RwL
 pub const PARKING_LOT_RWLOCK_WRITE_GUARD: [&str; 3] = ["lock_api", "rwlock", "RwLockWriteGuard"];
 pub const PATH_BUF_AS_PATH: [&str; 4] = ["std", "path", "PathBuf", "as_path"];
 pub const PATH_TO_PATH_BUF: [&str; 4] = ["std", "path", "Path", "to_path_buf"];
+pub const PEEKABLE: [&str; 5] = ["core", "iter", "adapters", "peekable", "Peekable"];
 pub const PERMISSIONS: [&str; 3] = ["std", "fs", "Permissions"];
 #[cfg_attr(not(unix), allow(clippy::invalid_paths))]
 pub const PERMISSIONS_FROM_MODE: [&str; 6] = ["std", "os", "unix", "fs", "PermissionsExt", "from_mode"];
diff --git a/src/tools/clippy/clippy_utils/src/ptr.rs b/src/tools/clippy/clippy_utils/src/ptr.rs
index 649b7b9940af..0226f74906b5 100644
--- a/src/tools/clippy/clippy_utils/src/ptr.rs
+++ b/src/tools/clippy/clippy_utils/src/ptr.rs
@@ -36,7 +36,7 @@ fn extract_clone_suggestions<'tcx>(
         if abort {
             return false;
         }
-        if let ExprKind::MethodCall(seg, [recv], _) = expr.kind {
+        if let ExprKind::MethodCall(seg, recv, [], _) = expr.kind {
             if path_to_local_id(recv, id) {
                 if seg.ident.name.as_str() == "capacity" {
                     abort = true;
diff --git a/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs b/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
index 74c222bbcbeb..f7ce71917726 100644
--- a/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
+++ b/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
@@ -6,8 +6,8 @@
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_middle::mir::{
-    Body, CastKind, NullOp, Operand, Place, ProjectionElem, Rvalue, Statement, StatementKind, Terminator,
-    TerminatorKind,
+    Body, CastKind, NonDivergingIntrinsic, NullOp, Operand, Place, ProjectionElem, Rvalue, Statement, StatementKind,
+    Terminator, TerminatorKind,
 };
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::{self, adjustment::PointerCast, Ty, TyCtxt};
@@ -82,7 +82,7 @@ fn check_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, span: Span) -> McfResult {
             ty::FnPtr(..) => {
                 return Err((span, "function pointers in const fn are unstable".into()));
             },
-            ty::Dynamic(preds, _) => {
+            ty::Dynamic(preds, _, _) => {
                 for pred in preds.iter() {
                     match pred.skip_binder() {
                         ty::ExistentialPredicate::AutoTrait(_) | ty::ExistentialPredicate::Projection(_) => {
@@ -161,6 +161,10 @@ fn check_rvalue<'tcx>(
         Rvalue::Cast(CastKind::PointerExposeAddress, _, _) => {
             Err((span, "casting pointers to ints is unstable in const fn".into()))
         },
+        Rvalue::Cast(CastKind::DynStar, _, _) => {
+            // FIXME(dyn-star)
+            unimplemented!()
+        },
         // binops are fine on integers
         Rvalue::BinaryOp(_, box (lhs, rhs)) | Rvalue::CheckedBinaryOp(_, box (lhs, rhs)) => {
             check_operand(tcx, lhs, span, body)?;
@@ -212,7 +216,11 @@ fn check_statement<'tcx>(
             check_place(tcx, **place, span, body)
         },
 
-        StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping { dst, src, count }) => {
+        StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(op)) => check_operand(tcx, op, span, body),
+
+        StatementKind::Intrinsic(box NonDivergingIntrinsic::CopyNonOverlapping(
+            rustc_middle::mir::CopyNonOverlapping { dst, src, count },
+        )) => {
             check_operand(tcx, dst, span, body)?;
             check_operand(tcx, src, span, body)?;
             check_operand(tcx, count, span, body)
@@ -252,6 +260,7 @@ fn check_place<'tcx>(tcx: TyCtxt<'tcx>, place: Place<'tcx>, span: Span, body: &B
                 }
             },
             ProjectionElem::ConstantIndex { .. }
+            | ProjectionElem::OpaqueCast(..)
             | ProjectionElem::Downcast(..)
             | ProjectionElem::Subslice { .. }
             | ProjectionElem::Deref
@@ -358,10 +367,21 @@ fn is_const_fn(tcx: TyCtxt<'_>, def_id: DefId, msrv: Option<RustcVersion>) -> bo
                 // Checking MSRV is manually necessary because `rustc` has no such concept. This entire
                 // function could be removed if `rustc` provided a MSRV-aware version of `is_const_fn`.
                 // as a part of an unimplemented MSRV check https://github.com/rust-lang/rust/issues/65262.
+
+                // HACK(nilstrieb): CURRENT_RUSTC_VERSION can return versions like 1.66.0-dev. `rustc-semver` doesn't accept
+                //                  the `-dev` version number so we have to strip it off.
+                let short_version = since
+                    .as_str()
+                    .split('-')
+                    .next()
+                    .expect("rustc_attr::StabilityLevel::Stable::since` is empty");
+
+                let since = rustc_span::Symbol::intern(short_version);
+
                 crate::meets_msrv(
                     msrv,
                     RustcVersion::parse(since.as_str())
-                        .expect("`rustc_attr::StabilityLevel::Stable::since` is ill-formatted"),
+                        .unwrap_or_else(|err| panic!("`rustc_attr::StabilityLevel::Stable::since` is ill-formatted: `{since}`, {err:?}")),
                 )
             } else {
                 // Unstable const fn with the feature enabled.
diff --git a/src/tools/clippy/clippy_utils/src/sugg.rs b/src/tools/clippy/clippy_utils/src/sugg.rs
index 081c98e2f3ce..f08275a4ac76 100644
--- a/src/tools/clippy/clippy_utils/src/sugg.rs
+++ b/src/tools/clippy/clippy_utils/src/sugg.rs
@@ -22,7 +22,7 @@ use std::fmt::{Display, Write as _};
 use std::ops::{Add, Neg, Not, Sub};
 
 /// A helper type to build suggestion correctly handling parentheses.
-#[derive(Clone, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub enum Sugg<'a> {
     /// An expression that never needs parentheses such as `1337` or `[0; 42]`.
     NonParen(Cow<'a, str>),
@@ -155,8 +155,8 @@ impl<'a> Sugg<'a> {
             | hir::ExprKind::Ret(..)
             | hir::ExprKind::Struct(..)
             | hir::ExprKind::Tup(..)
-            | hir::ExprKind::DropTemps(_)
             | hir::ExprKind::Err => Sugg::NonParen(get_snippet(expr.span)),
+            hir::ExprKind::DropTemps(inner) => Self::hir_from_snippet(inner, get_snippet),
             hir::ExprKind::Assign(lhs, rhs, _) => {
                 Sugg::BinOp(AssocOp::Assign, get_snippet(lhs.span), get_snippet(rhs.span))
             },
@@ -177,11 +177,11 @@ impl<'a> Sugg<'a> {
     pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self {
         use rustc_ast::ast::RangeLimits;
 
-        let get_whole_snippet = || {
-            if expr.span.from_expansion() {
-                snippet_with_macro_callsite(cx, expr.span, default)
+        let snippet_without_expansion = |cx, span: Span, default| {
+            if span.from_expansion() {
+                snippet_with_macro_callsite(cx, span, default)
             } else {
-                snippet(cx, expr.span, default)
+                snippet(cx, span, default)
             }
         };
 
@@ -192,7 +192,7 @@ impl<'a> Sugg<'a> {
             | ast::ExprKind::If(..)
             | ast::ExprKind::Let(..)
             | ast::ExprKind::Unary(..)
-            | ast::ExprKind::Match(..) => Sugg::MaybeParen(get_whole_snippet()),
+            | ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet_without_expansion(cx, expr.span, default)),
             ast::ExprKind::Async(..)
             | ast::ExprKind::Block(..)
             | ast::ExprKind::Break(..)
@@ -221,41 +221,45 @@ impl<'a> Sugg<'a> {
             | ast::ExprKind::Array(..)
             | ast::ExprKind::While(..)
             | ast::ExprKind::Await(..)
-            | ast::ExprKind::Err => Sugg::NonParen(get_whole_snippet()),
+            | ast::ExprKind::Err => Sugg::NonParen(snippet_without_expansion(cx, expr.span, default)),
             ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::HalfOpen) => Sugg::BinOp(
                 AssocOp::DotDot,
-                lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)),
-                rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)),
+                lhs.as_ref()
+                    .map_or("".into(), |lhs| snippet_without_expansion(cx, lhs.span, default)),
+                rhs.as_ref()
+                    .map_or("".into(), |rhs| snippet_without_expansion(cx, rhs.span, default)),
             ),
             ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::Closed) => Sugg::BinOp(
                 AssocOp::DotDotEq,
-                lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)),
-                rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)),
+                lhs.as_ref()
+                    .map_or("".into(), |lhs| snippet_without_expansion(cx, lhs.span, default)),
+                rhs.as_ref()
+                    .map_or("".into(), |rhs| snippet_without_expansion(cx, rhs.span, default)),
             ),
             ast::ExprKind::Assign(ref lhs, ref rhs, _) => Sugg::BinOp(
                 AssocOp::Assign,
-                snippet(cx, lhs.span, default),
-                snippet(cx, rhs.span, default),
+                snippet_without_expansion(cx, lhs.span, default),
+                snippet_without_expansion(cx, rhs.span, default),
             ),
             ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => Sugg::BinOp(
                 astbinop2assignop(op),
-                snippet(cx, lhs.span, default),
-                snippet(cx, rhs.span, default),
+                snippet_without_expansion(cx, lhs.span, default),
+                snippet_without_expansion(cx, rhs.span, default),
             ),
             ast::ExprKind::Binary(op, ref lhs, ref rhs) => Sugg::BinOp(
                 AssocOp::from_ast_binop(op.node),
-                snippet(cx, lhs.span, default),
-                snippet(cx, rhs.span, default),
+                snippet_without_expansion(cx, lhs.span, default),
+                snippet_without_expansion(cx, rhs.span, default),
             ),
             ast::ExprKind::Cast(ref lhs, ref ty) => Sugg::BinOp(
                 AssocOp::As,
-                snippet(cx, lhs.span, default),
-                snippet(cx, ty.span, default),
+                snippet_without_expansion(cx, lhs.span, default),
+                snippet_without_expansion(cx, ty.span, default),
             ),
             ast::ExprKind::Type(ref lhs, ref ty) => Sugg::BinOp(
                 AssocOp::Colon,
-                snippet(cx, lhs.span, default),
-                snippet(cx, ty.span, default),
+                snippet_without_expansion(cx, lhs.span, default),
+                snippet_without_expansion(cx, ty.span, default),
             ),
         }
     }
@@ -373,12 +377,14 @@ fn binop_to_string(op: AssocOp, lhs: &str, rhs: &str) -> String {
         | AssocOp::LessEqual
         | AssocOp::NotEqual
         | AssocOp::Greater
-        | AssocOp::GreaterEqual => format!(
-            "{} {} {}",
-            lhs,
-            op.to_ast_binop().expect("Those are AST ops").to_string(),
-            rhs
-        ),
+        | AssocOp::GreaterEqual => {
+            format!(
+                "{} {} {}",
+                lhs,
+                op.to_ast_binop().expect("Those are AST ops").to_string(),
+                rhs
+            )
+        },
         AssocOp::Assign => format!("{} = {}", lhs, rhs),
         AssocOp::AssignOp(op) => {
             format!("{} {}= {}", lhs, token_kind_to_string(&token::BinOp(op)), rhs)
@@ -868,15 +874,15 @@ impl<'tcx> DerefDelegate<'_, 'tcx> {
     /// indicates whether the function from `parent_expr` takes its args by double reference
     fn func_takes_arg_by_double_ref(&self, parent_expr: &'tcx hir::Expr<'_>, cmt_hir_id: HirId) -> bool {
         let ty = match parent_expr.kind {
-            ExprKind::MethodCall(_, call_args, _) => {
+            ExprKind::MethodCall(_, receiver, call_args, _) => {
                 if let Some(sig) = self
                     .cx
                     .typeck_results()
                     .type_dependent_def_id(parent_expr.hir_id)
                     .map(|did| self.cx.tcx.fn_sig(did).skip_binder())
                 {
-                    call_args
-                        .iter()
+                    std::iter::once(receiver)
+                        .chain(call_args.iter())
                         .position(|arg| arg.hir_id == cmt_hir_id)
                         .map(|i| sig.inputs()[i])
                 } else {
@@ -933,14 +939,14 @@ impl<'tcx> Delegate<'tcx> for DerefDelegate<'_, 'tcx> {
                     match &parent_expr.kind {
                         // given expression is the self argument and will be handled completely by the compiler
                         // i.e.: `|x| x.is_something()`
-                        ExprKind::MethodCall(_, [self_expr, ..], _) if self_expr.hir_id == cmt.hir_id => {
+                        ExprKind::MethodCall(_, self_expr, ..) if self_expr.hir_id == cmt.hir_id => {
                             let _ = write!(self.suggestion_start, "{}{}", start_snip, ident_str_with_proj);
                             self.next_pos = span.hi();
                             return;
                         },
                         // item is used in a call
                         // i.e.: `Call`: `|x| please(x)` or `MethodCall`: `|x| [1, 2, 3].contains(x)`
-                        ExprKind::Call(_, [call_args @ ..]) | ExprKind::MethodCall(_, [_, call_args @ ..], _) => {
+                        ExprKind::Call(_, [call_args @ ..]) | ExprKind::MethodCall(_, _, [call_args @ ..], _) => {
                             let expr = self.cx.tcx.hir().expect_expr(cmt.hir_id);
                             let arg_ty_kind = self.cx.typeck_results().expr_ty(expr).kind();
 
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
index e7d670766a05..56343880320d 100644
--- a/src/tools/clippy/clippy_utils/src/ty.rs
+++ b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -12,7 +12,7 @@ use rustc_hir::{Expr, FnDecl, LangItem, TyKind, Unsafety};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::LateContext;
 use rustc_middle::mir::interpret::{ConstValue, Scalar};
-use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst};
+use rustc_middle::ty::{GenericArg, GenericArgKind};
 use rustc_middle::ty::{
     self, AdtDef, Binder, BoundRegion, DefIdTree, FnSig, IntTy, ParamEnv, Predicate, PredicateKind, ProjectionTy,
     Region, RegionKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, UintTy, VariantDef, VariantDiscr,
@@ -31,6 +31,13 @@ pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
     ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
 }
 
+/// This checks whether a given type is known to implement Debug.
+pub fn has_debug_impl<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
+    cx.tcx
+        .get_diagnostic_item(sym::Debug)
+        .map_or(false, |debug| implements_trait(cx, ty, debug, &[]))
+}
+
 /// Checks whether a type can be partially moved.
 pub fn can_partially_move_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
     if has_drop(cx, ty) || is_copy(cx, ty) {
@@ -43,14 +50,6 @@ pub fn can_partially_move_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool
     }
 }
 
-/// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
-pub fn contains_ty<'tcx>(ty: Ty<'tcx>, other_ty: Ty<'tcx>) -> bool {
-    ty.walk().any(|inner| match inner.unpack() {
-        GenericArgKind::Type(inner_ty) => other_ty == inner_ty,
-        GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
-    })
-}
-
 /// Walks into `ty` and returns `true` if any inner type is an instance of the given adt
 /// constructor.
 pub fn contains_adt_constructor<'tcx>(ty: Ty<'tcx>, adt: AdtDef<'tcx>) -> bool {
@@ -209,7 +208,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
             }
             false
         },
-        ty::Dynamic(binder, _) => {
+        ty::Dynamic(binder, _, _) => {
             for predicate in binder.iter() {
                 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
                     if cx.tcx.has_attr(trait_ref.def_id, sym::must_use) {
@@ -410,7 +409,7 @@ pub fn peel_mid_ty_refs(ty: Ty<'_>) -> (Ty<'_>, usize) {
     peel(ty, 0)
 }
 
-/// Peels off all references on the type.Returns the underlying type, the number of references
+/// Peels off all references on the type. Returns the underlying type, the number of references
 /// removed, and whether the pointer is ultimately mutable or not.
 pub fn peel_mid_ty_refs_is_mutable(ty: Ty<'_>) -> (Ty<'_>, usize, Mutability) {
     fn f(ty: Ty<'_>, count: usize, mutability: Mutability) -> (Ty<'_>, usize, Mutability) {
@@ -587,7 +586,7 @@ pub fn ty_sig<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<ExprFnSig<'t
         ty::FnDef(id, subs) => Some(ExprFnSig::Sig(cx.tcx.bound_fn_sig(id).subst(cx.tcx, subs), Some(id))),
         ty::Opaque(id, _) => sig_from_bounds(cx, ty, cx.tcx.item_bounds(id), cx.tcx.opt_parent(id)),
         ty::FnPtr(sig) => Some(ExprFnSig::Sig(sig, None)),
-        ty::Dynamic(bounds, _) => {
+        ty::Dynamic(bounds, _, _) => {
             let lang_items = cx.tcx.lang_items();
             match bounds.principal() {
                 Some(bound)
@@ -839,3 +838,53 @@ pub fn ty_is_fn_once_param<'tcx>(tcx: TyCtxt<'_>, ty: Ty<'tcx>, predicates: &'tc
         })
         .unwrap_or(false)
 }
+
+/// Comes up with an "at least" guesstimate for the type's size, not taking into
+/// account the layout of type parameters.
+pub fn approx_ty_size<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> u64 {
+    use rustc_middle::ty::layout::LayoutOf;
+    if !is_normalizable(cx, cx.param_env, ty) {
+        return 0;
+    }
+    match (cx.layout_of(ty).map(|layout| layout.size.bytes()), ty.kind()) {
+        (Ok(size), _) => size,
+        (Err(_), ty::Tuple(list)) => list.as_substs().types().map(|t| approx_ty_size(cx, t)).sum(),
+        (Err(_), ty::Array(t, n)) => {
+            n.try_eval_usize(cx.tcx, cx.param_env).unwrap_or_default() * approx_ty_size(cx, *t)
+        },
+        (Err(_), ty::Adt(def, subst)) if def.is_struct() => def
+            .variants()
+            .iter()
+            .map(|v| {
+                v.fields
+                    .iter()
+                    .map(|field| approx_ty_size(cx, field.ty(cx.tcx, subst)))
+                    .sum::<u64>()
+            })
+            .sum(),
+        (Err(_), ty::Adt(def, subst)) if def.is_enum() => def
+            .variants()
+            .iter()
+            .map(|v| {
+                v.fields
+                    .iter()
+                    .map(|field| approx_ty_size(cx, field.ty(cx.tcx, subst)))
+                    .sum::<u64>()
+            })
+            .max()
+            .unwrap_or_default(),
+        (Err(_), ty::Adt(def, subst)) if def.is_union() => def
+            .variants()
+            .iter()
+            .map(|v| {
+                v.fields
+                    .iter()
+                    .map(|field| approx_ty_size(cx, field.ty(cx.tcx, subst)))
+                    .max()
+                    .unwrap_or_default()
+            })
+            .max()
+            .unwrap_or_default(),
+        (Err(_), _) => 0,
+    }
+}
diff --git a/src/tools/clippy/clippy_utils/src/usage.rs b/src/tools/clippy/clippy_utils/src/usage.rs
index 3af5dfb62f97..a7c08839f524 100644
--- a/src/tools/clippy/clippy_utils/src/usage.rs
+++ b/src/tools/clippy/clippy_utils/src/usage.rs
@@ -21,7 +21,7 @@ pub fn mutated_variables<'tcx>(expr: &'tcx Expr<'_>, cx: &LateContext<'tcx>) ->
         ExprUseVisitor::new(
             &mut delegate,
             &infcx,
-            expr.hir_id.owner,
+            expr.hir_id.owner.def_id,
             cx.param_env,
             cx.typeck_results(),
         )
diff --git a/src/tools/clippy/clippy_utils/src/visitors.rs b/src/tools/clippy/clippy_utils/src/visitors.rs
index bae8ad9f5659..232d571902b6 100644
--- a/src/tools/clippy/clippy_utils/src/visitors.rs
+++ b/src/tools/clippy/clippy_utils/src/visitors.rs
@@ -274,7 +274,7 @@ pub fn is_res_used(cx: &LateContext<'_>, res: Res, body: BodyId) -> bool {
         }
         !found
     })
-    .visit_expr(&cx.tcx.hir().body(body).value);
+    .visit_expr(cx.tcx.hir().body(body).value);
     found
 }
 
@@ -568,6 +568,7 @@ pub fn for_each_local_use_after_expr<'tcx, B>(
 // Calls the given function for every unconsumed temporary created by the expression. Note the
 // function is only guaranteed to be called for types which need to be dropped, but it may be called
 // for other types.
+#[allow(clippy::too_many_lines)]
 pub fn for_each_unconsumed_temporary<'tcx, B>(
     cx: &LateContext<'tcx>,
     e: &'tcx Expr<'tcx>,
@@ -620,7 +621,13 @@ pub fn for_each_unconsumed_temporary<'tcx, B>(
                     helper(typeck, true, arg, f)?;
                 }
             },
-            ExprKind::MethodCall(_, args, _) | ExprKind::Tup(args) | ExprKind::Array(args) => {
+            ExprKind::MethodCall(_, receiver, args, _) => {
+                helper(typeck, true, receiver, f)?;
+                for arg in args {
+                    helper(typeck, true, arg, f)?;
+                }
+            },
+            ExprKind::Tup(args) | ExprKind::Array(args) => {
                 for arg in args {
                     helper(typeck, true, arg, f)?;
                 }
diff --git a/src/tools/clippy/lintcheck/lintcheck_crates.toml b/src/tools/clippy/lintcheck/lintcheck_crates.toml
index 4fbae8614ca3..ebbe9c9ae675 100644
--- a/src/tools/clippy/lintcheck/lintcheck_crates.toml
+++ b/src/tools/clippy/lintcheck/lintcheck_crates.toml
@@ -1,6 +1,6 @@
 [crates]
 # some of these are from cargotest
-cargo = {name = "cargo", versions = ['0.49.0']}
+cargo = {name = "cargo", versions = ['0.64.0']}
 iron = {name = "iron", versions = ['0.6.1']}
 ripgrep = {name = "ripgrep", versions = ['12.1.1']}
 xsv = {name = "xsv", versions = ['0.13.0']}
diff --git a/src/tools/clippy/rust-toolchain b/src/tools/clippy/rust-toolchain
index 7e14df4feea6..b6976366dafc 100644
--- a/src/tools/clippy/rust-toolchain
+++ b/src/tools/clippy/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2022-08-11"
+channel = "nightly-2022-09-08"
 components = ["cargo", "llvm-tools-preview", "rust-src", "rust-std", "rustc", "rustc-dev", "rustfmt"]
diff --git a/src/tools/clippy/rustc_tools_util/src/lib.rs b/src/tools/clippy/rustc_tools_util/src/lib.rs
index 5f289918a7c1..429dddc42ea9 100644
--- a/src/tools/clippy/rustc_tools_util/src/lib.rs
+++ b/src/tools/clippy/rustc_tools_util/src/lib.rs
@@ -84,7 +84,7 @@ impl std::fmt::Debug for VersionInfo {
 #[must_use]
 pub fn get_commit_hash() -> Option<String> {
     std::process::Command::new("git")
-        .args(&["rev-parse", "--short", "HEAD"])
+        .args(["rev-parse", "--short", "HEAD"])
         .output()
         .ok()
         .and_then(|r| String::from_utf8(r.stdout).ok())
@@ -93,7 +93,7 @@ pub fn get_commit_hash() -> Option<String> {
 #[must_use]
 pub fn get_commit_date() -> Option<String> {
     std::process::Command::new("git")
-        .args(&["log", "-1", "--date=short", "--pretty=format:%cd"])
+        .args(["log", "-1", "--date=short", "--pretty=format:%cd"])
         .output()
         .ok()
         .and_then(|r| String::from_utf8(r.stdout).ok())
diff --git a/src/tools/clippy/src/docs.rs b/src/tools/clippy/src/docs.rs
new file mode 100644
index 000000000000..6c89b4dde372
--- /dev/null
+++ b/src/tools/clippy/src/docs.rs
@@ -0,0 +1,596 @@
+// autogenerated. Please look at /clippy_dev/src/update_lints.rs
+
+macro_rules! include_lint {
+    ($file_name: expr) => {
+        include_str!($file_name)
+    };
+}
+
+macro_rules! docs {
+    ($($lint_name: expr,)*) => {
+        pub fn explain(lint: &str) {
+            println!("{}", match lint {
+                $(
+                    $lint_name => include_lint!(concat!("docs/", concat!($lint_name, ".txt"))),
+                )*
+                _ => "unknown lint",
+            })
+        }
+    }
+}
+
+docs! {
+    "absurd_extreme_comparisons",
+    "alloc_instead_of_core",
+    "allow_attributes_without_reason",
+    "almost_complete_letter_range",
+    "almost_swapped",
+    "approx_constant",
+    "arithmetic_side_effects",
+    "as_conversions",
+    "as_underscore",
+    "assertions_on_constants",
+    "assertions_on_result_states",
+    "assign_op_pattern",
+    "async_yields_async",
+    "await_holding_invalid_type",
+    "await_holding_lock",
+    "await_holding_refcell_ref",
+    "bad_bit_mask",
+    "bind_instead_of_map",
+    "blanket_clippy_restriction_lints",
+    "blocks_in_if_conditions",
+    "bool_assert_comparison",
+    "bool_comparison",
+    "bool_to_int_with_if",
+    "borrow_as_ptr",
+    "borrow_deref_ref",
+    "borrow_interior_mutable_const",
+    "borrowed_box",
+    "box_collection",
+    "boxed_local",
+    "branches_sharing_code",
+    "builtin_type_shadow",
+    "bytes_count_to_len",
+    "bytes_nth",
+    "cargo_common_metadata",
+    "case_sensitive_file_extension_comparisons",
+    "cast_abs_to_unsigned",
+    "cast_enum_constructor",
+    "cast_enum_truncation",
+    "cast_lossless",
+    "cast_possible_truncation",
+    "cast_possible_wrap",
+    "cast_precision_loss",
+    "cast_ptr_alignment",
+    "cast_ref_to_mut",
+    "cast_sign_loss",
+    "cast_slice_different_sizes",
+    "cast_slice_from_raw_parts",
+    "char_lit_as_u8",
+    "chars_last_cmp",
+    "chars_next_cmp",
+    "checked_conversions",
+    "clone_double_ref",
+    "clone_on_copy",
+    "clone_on_ref_ptr",
+    "cloned_instead_of_copied",
+    "cmp_nan",
+    "cmp_null",
+    "cmp_owned",
+    "cognitive_complexity",
+    "collapsible_else_if",
+    "collapsible_if",
+    "collapsible_match",
+    "collapsible_str_replace",
+    "comparison_chain",
+    "comparison_to_empty",
+    "copy_iterator",
+    "crate_in_macro_def",
+    "create_dir",
+    "crosspointer_transmute",
+    "dbg_macro",
+    "debug_assert_with_mut_call",
+    "decimal_literal_representation",
+    "declare_interior_mutable_const",
+    "default_instead_of_iter_empty",
+    "default_numeric_fallback",
+    "default_trait_access",
+    "default_union_representation",
+    "deprecated_cfg_attr",
+    "deprecated_semver",
+    "deref_addrof",
+    "deref_by_slicing",
+    "derivable_impls",
+    "derive_hash_xor_eq",
+    "derive_ord_xor_partial_ord",
+    "derive_partial_eq_without_eq",
+    "disallowed_methods",
+    "disallowed_names",
+    "disallowed_script_idents",
+    "disallowed_types",
+    "diverging_sub_expression",
+    "doc_link_with_quotes",
+    "doc_markdown",
+    "double_comparisons",
+    "double_must_use",
+    "double_neg",
+    "double_parens",
+    "drop_copy",
+    "drop_non_drop",
+    "drop_ref",
+    "duplicate_mod",
+    "duplicate_underscore_argument",
+    "duration_subsec",
+    "else_if_without_else",
+    "empty_drop",
+    "empty_enum",
+    "empty_line_after_outer_attr",
+    "empty_loop",
+    "empty_structs_with_brackets",
+    "enum_clike_unportable_variant",
+    "enum_glob_use",
+    "enum_variant_names",
+    "eq_op",
+    "equatable_if_let",
+    "erasing_op",
+    "err_expect",
+    "excessive_precision",
+    "exhaustive_enums",
+    "exhaustive_structs",
+    "exit",
+    "expect_fun_call",
+    "expect_used",
+    "expl_impl_clone_on_copy",
+    "explicit_auto_deref",
+    "explicit_counter_loop",
+    "explicit_deref_methods",
+    "explicit_into_iter_loop",
+    "explicit_iter_loop",
+    "explicit_write",
+    "extend_with_drain",
+    "extra_unused_lifetimes",
+    "fallible_impl_from",
+    "field_reassign_with_default",
+    "filetype_is_file",
+    "filter_map_identity",
+    "filter_map_next",
+    "filter_next",
+    "flat_map_identity",
+    "flat_map_option",
+    "float_arithmetic",
+    "float_cmp",
+    "float_cmp_const",
+    "float_equality_without_abs",
+    "fn_address_comparisons",
+    "fn_params_excessive_bools",
+    "fn_to_numeric_cast",
+    "fn_to_numeric_cast_any",
+    "fn_to_numeric_cast_with_truncation",
+    "for_kv_map",
+    "for_loops_over_fallibles",
+    "forget_copy",
+    "forget_non_drop",
+    "forget_ref",
+    "format_in_format_args",
+    "format_push_string",
+    "from_iter_instead_of_collect",
+    "from_over_into",
+    "from_str_radix_10",
+    "future_not_send",
+    "get_first",
+    "get_last_with_len",
+    "get_unwrap",
+    "identity_op",
+    "if_let_mutex",
+    "if_not_else",
+    "if_same_then_else",
+    "if_then_some_else_none",
+    "ifs_same_cond",
+    "implicit_clone",
+    "implicit_hasher",
+    "implicit_return",
+    "implicit_saturating_sub",
+    "imprecise_flops",
+    "inconsistent_digit_grouping",
+    "inconsistent_struct_constructor",
+    "index_refutable_slice",
+    "indexing_slicing",
+    "ineffective_bit_mask",
+    "inefficient_to_string",
+    "infallible_destructuring_match",
+    "infinite_iter",
+    "inherent_to_string",
+    "inherent_to_string_shadow_display",
+    "init_numbered_fields",
+    "inline_always",
+    "inline_asm_x86_att_syntax",
+    "inline_asm_x86_intel_syntax",
+    "inline_fn_without_body",
+    "inspect_for_each",
+    "int_plus_one",
+    "integer_arithmetic",
+    "integer_division",
+    "into_iter_on_ref",
+    "invalid_null_ptr_usage",
+    "invalid_regex",
+    "invalid_upcast_comparisons",
+    "invalid_utf8_in_unchecked",
+    "invisible_characters",
+    "is_digit_ascii_radix",
+    "items_after_statements",
+    "iter_cloned_collect",
+    "iter_count",
+    "iter_kv_map",
+    "iter_next_loop",
+    "iter_next_slice",
+    "iter_not_returning_iterator",
+    "iter_nth",
+    "iter_nth_zero",
+    "iter_on_empty_collections",
+    "iter_on_single_items",
+    "iter_overeager_cloned",
+    "iter_skip_next",
+    "iter_with_drain",
+    "iterator_step_by_zero",
+    "just_underscores_and_digits",
+    "large_const_arrays",
+    "large_digit_groups",
+    "large_enum_variant",
+    "large_include_file",
+    "large_stack_arrays",
+    "large_types_passed_by_value",
+    "len_without_is_empty",
+    "len_zero",
+    "let_and_return",
+    "let_underscore_drop",
+    "let_underscore_lock",
+    "let_underscore_must_use",
+    "let_unit_value",
+    "linkedlist",
+    "lossy_float_literal",
+    "macro_use_imports",
+    "main_recursion",
+    "manual_assert",
+    "manual_async_fn",
+    "manual_bits",
+    "manual_filter_map",
+    "manual_find",
+    "manual_find_map",
+    "manual_flatten",
+    "manual_instant_elapsed",
+    "manual_map",
+    "manual_memcpy",
+    "manual_non_exhaustive",
+    "manual_ok_or",
+    "manual_range_contains",
+    "manual_rem_euclid",
+    "manual_retain",
+    "manual_saturating_arithmetic",
+    "manual_split_once",
+    "manual_str_repeat",
+    "manual_string_new",
+    "manual_strip",
+    "manual_swap",
+    "manual_unwrap_or",
+    "many_single_char_names",
+    "map_clone",
+    "map_collect_result_unit",
+    "map_entry",
+    "map_err_ignore",
+    "map_flatten",
+    "map_identity",
+    "map_unwrap_or",
+    "match_as_ref",
+    "match_bool",
+    "match_like_matches_macro",
+    "match_on_vec_items",
+    "match_overlapping_arm",
+    "match_ref_pats",
+    "match_result_ok",
+    "match_same_arms",
+    "match_single_binding",
+    "match_str_case_mismatch",
+    "match_wild_err_arm",
+    "match_wildcard_for_single_variants",
+    "maybe_infinite_iter",
+    "mem_forget",
+    "mem_replace_option_with_none",
+    "mem_replace_with_default",
+    "mem_replace_with_uninit",
+    "min_max",
+    "mismatched_target_os",
+    "mismatching_type_param_order",
+    "misrefactored_assign_op",
+    "missing_const_for_fn",
+    "missing_docs_in_private_items",
+    "missing_enforced_import_renames",
+    "missing_errors_doc",
+    "missing_inline_in_public_items",
+    "missing_panics_doc",
+    "missing_safety_doc",
+    "missing_spin_loop",
+    "mistyped_literal_suffixes",
+    "mixed_case_hex_literals",
+    "mixed_read_write_in_expression",
+    "mod_module_files",
+    "module_inception",
+    "module_name_repetitions",
+    "modulo_arithmetic",
+    "modulo_one",
+    "multi_assignments",
+    "multiple_crate_versions",
+    "multiple_inherent_impl",
+    "must_use_candidate",
+    "must_use_unit",
+    "mut_from_ref",
+    "mut_mut",
+    "mut_mutex_lock",
+    "mut_range_bound",
+    "mutable_key_type",
+    "mutex_atomic",
+    "mutex_integer",
+    "naive_bytecount",
+    "needless_arbitrary_self_type",
+    "needless_bitwise_bool",
+    "needless_bool",
+    "needless_borrow",
+    "needless_borrowed_reference",
+    "needless_collect",
+    "needless_continue",
+    "needless_doctest_main",
+    "needless_for_each",
+    "needless_late_init",
+    "needless_lifetimes",
+    "needless_match",
+    "needless_option_as_deref",
+    "needless_option_take",
+    "needless_parens_on_range_literals",
+    "needless_pass_by_value",
+    "needless_question_mark",
+    "needless_range_loop",
+    "needless_return",
+    "needless_splitn",
+    "needless_update",
+    "neg_cmp_op_on_partial_ord",
+    "neg_multiply",
+    "negative_feature_names",
+    "never_loop",
+    "new_ret_no_self",
+    "new_without_default",
+    "no_effect",
+    "no_effect_replace",
+    "no_effect_underscore_binding",
+    "non_ascii_literal",
+    "non_octal_unix_permissions",
+    "non_send_fields_in_send_ty",
+    "nonminimal_bool",
+    "nonsensical_open_options",
+    "nonstandard_macro_braces",
+    "not_unsafe_ptr_arg_deref",
+    "obfuscated_if_else",
+    "octal_escapes",
+    "ok_expect",
+    "only_used_in_recursion",
+    "op_ref",
+    "option_as_ref_deref",
+    "option_env_unwrap",
+    "option_filter_map",
+    "option_if_let_else",
+    "option_map_or_none",
+    "option_map_unit_fn",
+    "option_option",
+    "or_fun_call",
+    "or_then_unwrap",
+    "out_of_bounds_indexing",
+    "overflow_check_conditional",
+    "overly_complex_bool_expr",
+    "panic",
+    "panic_in_result_fn",
+    "panicking_unwrap",
+    "partialeq_ne_impl",
+    "partialeq_to_none",
+    "path_buf_push_overwrite",
+    "pattern_type_mismatch",
+    "possible_missing_comma",
+    "precedence",
+    "print_in_format_impl",
+    "print_literal",
+    "print_stderr",
+    "print_stdout",
+    "print_with_newline",
+    "println_empty_string",
+    "ptr_arg",
+    "ptr_as_ptr",
+    "ptr_eq",
+    "ptr_offset_with_cast",
+    "pub_use",
+    "question_mark",
+    "range_minus_one",
+    "range_plus_one",
+    "range_zip_with_len",
+    "rc_buffer",
+    "rc_clone_in_vec_init",
+    "rc_mutex",
+    "read_zero_byte_vec",
+    "recursive_format_impl",
+    "redundant_allocation",
+    "redundant_clone",
+    "redundant_closure",
+    "redundant_closure_call",
+    "redundant_closure_for_method_calls",
+    "redundant_else",
+    "redundant_feature_names",
+    "redundant_field_names",
+    "redundant_pattern",
+    "redundant_pattern_matching",
+    "redundant_pub_crate",
+    "redundant_slicing",
+    "redundant_static_lifetimes",
+    "ref_binding_to_reference",
+    "ref_option_ref",
+    "repeat_once",
+    "rest_pat_in_fully_bound_structs",
+    "result_large_err",
+    "result_map_or_into_option",
+    "result_map_unit_fn",
+    "result_unit_err",
+    "return_self_not_must_use",
+    "reversed_empty_ranges",
+    "same_functions_in_if_condition",
+    "same_item_push",
+    "same_name_method",
+    "search_is_some",
+    "self_assignment",
+    "self_named_constructors",
+    "self_named_module_files",
+    "semicolon_if_nothing_returned",
+    "separated_literal_suffix",
+    "serde_api_misuse",
+    "shadow_reuse",
+    "shadow_same",
+    "shadow_unrelated",
+    "short_circuit_statement",
+    "should_implement_trait",
+    "significant_drop_in_scrutinee",
+    "similar_names",
+    "single_char_add_str",
+    "single_char_lifetime_names",
+    "single_char_pattern",
+    "single_component_path_imports",
+    "single_element_loop",
+    "single_match",
+    "single_match_else",
+    "size_of_in_element_count",
+    "skip_while_next",
+    "slow_vector_initialization",
+    "stable_sort_primitive",
+    "std_instead_of_alloc",
+    "std_instead_of_core",
+    "str_to_string",
+    "string_add",
+    "string_add_assign",
+    "string_extend_chars",
+    "string_from_utf8_as_bytes",
+    "string_lit_as_bytes",
+    "string_slice",
+    "string_to_string",
+    "strlen_on_c_strings",
+    "struct_excessive_bools",
+    "suboptimal_flops",
+    "suspicious_arithmetic_impl",
+    "suspicious_assignment_formatting",
+    "suspicious_else_formatting",
+    "suspicious_map",
+    "suspicious_op_assign_impl",
+    "suspicious_operation_groupings",
+    "suspicious_splitn",
+    "suspicious_to_owned",
+    "suspicious_unary_op_formatting",
+    "swap_ptr_to_ref",
+    "tabs_in_doc_comments",
+    "temporary_assignment",
+    "to_digit_is_some",
+    "to_string_in_format_args",
+    "todo",
+    "too_many_arguments",
+    "too_many_lines",
+    "toplevel_ref_arg",
+    "trailing_empty_array",
+    "trait_duplication_in_bounds",
+    "transmute_bytes_to_str",
+    "transmute_float_to_int",
+    "transmute_int_to_bool",
+    "transmute_int_to_char",
+    "transmute_int_to_float",
+    "transmute_num_to_bytes",
+    "transmute_ptr_to_ptr",
+    "transmute_ptr_to_ref",
+    "transmute_undefined_repr",
+    "transmutes_expressible_as_ptr_casts",
+    "transmuting_null",
+    "trim_split_whitespace",
+    "trivial_regex",
+    "trivially_copy_pass_by_ref",
+    "try_err",
+    "type_complexity",
+    "type_repetition_in_bounds",
+    "undocumented_unsafe_blocks",
+    "undropped_manually_drops",
+    "unicode_not_nfc",
+    "unimplemented",
+    "uninit_assumed_init",
+    "uninit_vec",
+    "unit_arg",
+    "unit_cmp",
+    "unit_hash",
+    "unit_return_expecting_ord",
+    "unnecessary_cast",
+    "unnecessary_filter_map",
+    "unnecessary_find_map",
+    "unnecessary_fold",
+    "unnecessary_join",
+    "unnecessary_lazy_evaluations",
+    "unnecessary_mut_passed",
+    "unnecessary_operation",
+    "unnecessary_owned_empty_strings",
+    "unnecessary_self_imports",
+    "unnecessary_sort_by",
+    "unnecessary_to_owned",
+    "unnecessary_unwrap",
+    "unnecessary_wraps",
+    "unneeded_field_pattern",
+    "unneeded_wildcard_pattern",
+    "unnested_or_patterns",
+    "unreachable",
+    "unreadable_literal",
+    "unsafe_derive_deserialize",
+    "unsafe_removed_from_name",
+    "unseparated_literal_suffix",
+    "unsound_collection_transmute",
+    "unused_async",
+    "unused_io_amount",
+    "unused_peekable",
+    "unused_rounding",
+    "unused_self",
+    "unused_unit",
+    "unusual_byte_groupings",
+    "unwrap_in_result",
+    "unwrap_or_else_default",
+    "unwrap_used",
+    "upper_case_acronyms",
+    "use_debug",
+    "use_self",
+    "used_underscore_binding",
+    "useless_asref",
+    "useless_attribute",
+    "useless_conversion",
+    "useless_format",
+    "useless_let_if_seq",
+    "useless_transmute",
+    "useless_vec",
+    "vec_box",
+    "vec_init_then_push",
+    "vec_resize_to_zero",
+    "verbose_bit_mask",
+    "verbose_file_reads",
+    "vtable_address_comparisons",
+    "while_immutable_condition",
+    "while_let_loop",
+    "while_let_on_iterator",
+    "wildcard_dependencies",
+    "wildcard_enum_match_arm",
+    "wildcard_imports",
+    "wildcard_in_or_patterns",
+    "write_literal",
+    "write_with_newline",
+    "writeln_empty_string",
+    "wrong_self_convention",
+    "wrong_transmute",
+    "zero_divided_by_zero",
+    "zero_prefixed_literal",
+    "zero_ptr",
+    "zero_sized_map_values",
+    "zst_offset",
+
+}
diff --git a/src/tools/clippy/src/docs/absurd_extreme_comparisons.txt b/src/tools/clippy/src/docs/absurd_extreme_comparisons.txt
new file mode 100644
index 000000000000..590bee28aa23
--- /dev/null
+++ b/src/tools/clippy/src/docs/absurd_extreme_comparisons.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for comparisons where one side of the relation is
+either the minimum or maximum value for its type and warns if it involves a
+case that is always true or always false. Only integer and boolean types are
+checked.
+
+### Why is this bad?
+An expression like `min <= x` may misleadingly imply
+that it is possible for `x` to be less than the minimum. Expressions like
+`max < x` are probably mistakes.
+
+### Known problems
+For `usize` the size of the current compile target will
+be assumed (e.g., 64 bits on 64 bit systems). This means code that uses such
+a comparison to detect target pointer width will trigger this lint. One can
+use `mem::sizeof` and compare its value or conditional compilation
+attributes
+like `#[cfg(target_pointer_width = "64")] ..` instead.
+
+### Example
+```
+let vec: Vec<isize> = Vec::new();
+if vec.len() <= 0 {}
+if 100 > i32::MAX {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/alloc_instead_of_core.txt b/src/tools/clippy/src/docs/alloc_instead_of_core.txt
new file mode 100644
index 000000000000..488a36e9276c
--- /dev/null
+++ b/src/tools/clippy/src/docs/alloc_instead_of_core.txt
@@ -0,0 +1,18 @@
+### What it does
+
+Finds items imported through `alloc` when available through `core`.
+
+### Why is this bad?
+
+Crates which have `no_std` compatibility and may optionally require alloc may wish to ensure types are
+imported from core to ensure disabling `alloc` does not cause the crate to fail to compile. This lint
+is also useful for crates migrating to become `no_std` compatible.
+
+### Example
+```
+use alloc::slice::from_ref;
+```
+Use instead:
+```
+use core::slice::from_ref;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/allow_attributes_without_reason.txt b/src/tools/clippy/src/docs/allow_attributes_without_reason.txt
new file mode 100644
index 000000000000..fcc4f49b08b3
--- /dev/null
+++ b/src/tools/clippy/src/docs/allow_attributes_without_reason.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for attributes that allow lints without a reason.
+
+(This requires the `lint_reasons` feature)
+
+### Why is this bad?
+Allowing a lint should always have a reason. This reason should be documented to
+ensure that others understand the reasoning
+
+### Example
+```
+#![feature(lint_reasons)]
+
+#![allow(clippy::some_lint)]
+```
+
+Use instead:
+```
+#![feature(lint_reasons)]
+
+#![allow(clippy::some_lint, reason = "False positive rust-lang/rust-clippy#1002020")]
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/almost_complete_letter_range.txt b/src/tools/clippy/src/docs/almost_complete_letter_range.txt
new file mode 100644
index 000000000000..01cbaf9eae25
--- /dev/null
+++ b/src/tools/clippy/src/docs/almost_complete_letter_range.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for ranges which almost include the entire range of letters from 'a' to 'z', but
+don't because they're a half open range.
+
+### Why is this bad?
+This (`'a'..'z'`) is almost certainly a typo meant to include all letters.
+
+### Example
+```
+let _ = 'a'..'z';
+```
+Use instead:
+```
+let _ = 'a'..='z';
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/almost_swapped.txt b/src/tools/clippy/src/docs/almost_swapped.txt
new file mode 100644
index 000000000000..cd10a8d5409b
--- /dev/null
+++ b/src/tools/clippy/src/docs/almost_swapped.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for `foo = bar; bar = foo` sequences.
+
+### Why is this bad?
+This looks like a failed attempt to swap.
+
+### Example
+```
+a = b;
+b = a;
+```
+If swapping is intended, use `swap()` instead:
+```
+std::mem::swap(&mut a, &mut b);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/approx_constant.txt b/src/tools/clippy/src/docs/approx_constant.txt
new file mode 100644
index 000000000000..393fa4b5ef7e
--- /dev/null
+++ b/src/tools/clippy/src/docs/approx_constant.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for floating point literals that approximate
+constants which are defined in
+[`std::f32::consts`](https://doc.rust-lang.org/stable/std/f32/consts/#constants)
+or
+[`std::f64::consts`](https://doc.rust-lang.org/stable/std/f64/consts/#constants),
+respectively, suggesting to use the predefined constant.
+
+### Why is this bad?
+Usually, the definition in the standard library is more
+precise than what people come up with. If you find that your definition is
+actually more precise, please [file a Rust
+issue](https://github.com/rust-lang/rust/issues).
+
+### Example
+```
+let x = 3.14;
+let y = 1_f64 / x;
+```
+Use instead:
+```
+let x = std::f32::consts::PI;
+let y = std::f64::consts::FRAC_1_PI;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/arithmetic_side_effects.txt b/src/tools/clippy/src/docs/arithmetic_side_effects.txt
new file mode 100644
index 000000000000..6c7d51a4989e
--- /dev/null
+++ b/src/tools/clippy/src/docs/arithmetic_side_effects.txt
@@ -0,0 +1,33 @@
+### What it does
+Checks any kind of arithmetic operation of any type.
+
+Operators like `+`, `-`, `*` or `<<` are usually capable of overflowing according to the [Rust
+Reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#overflow),
+or can panic (`/`, `%`).
+
+Known safe built-in types like `Wrapping` or `Saturing`, floats, operations in constant
+environments, allowed types and non-constant operations that won't overflow are ignored.
+
+### Why is this bad?
+For integers, overflow will trigger a panic in debug builds or wrap the result in
+release mode; division by zero will cause a panic in either mode. As a result, it is
+desirable to explicitly call checked, wrapping or saturating arithmetic methods.
+
+#### Example
+```
+// `n` can be any number, including `i32::MAX`.
+fn foo(n: i32) -> i32 {
+  n + 1
+}
+```
+
+Third-party types can also overflow or present unwanted side-effects.
+
+#### Example
+```
+use rust_decimal::Decimal;
+let _n = Decimal::MAX + Decimal::MAX;
+```
+
+### Allowed types
+Custom allowed types can be specified through the "arithmetic-side-effects-allowed" filter.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/as_conversions.txt b/src/tools/clippy/src/docs/as_conversions.txt
new file mode 100644
index 000000000000..4af479bd8111
--- /dev/null
+++ b/src/tools/clippy/src/docs/as_conversions.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for usage of `as` conversions.
+
+Note that this lint is specialized in linting *every single* use of `as`
+regardless of whether good alternatives exist or not.
+If you want more precise lints for `as`, please consider using these separate lints:
+`unnecessary_cast`, `cast_lossless/cast_possible_truncation/cast_possible_wrap/cast_precision_loss/cast_sign_loss`,
+`fn_to_numeric_cast(_with_truncation)`, `char_lit_as_u8`, `ref_to_mut` and `ptr_as_ptr`.
+There is a good explanation the reason why this lint should work in this way and how it is useful
+[in this issue](https://github.com/rust-lang/rust-clippy/issues/5122).
+
+### Why is this bad?
+`as` conversions will perform many kinds of
+conversions, including silently lossy conversions and dangerous coercions.
+There are cases when it makes sense to use `as`, so the lint is
+Allow by default.
+
+### Example
+```
+let a: u32;
+...
+f(a as u16);
+```
+
+Use instead:
+```
+f(a.try_into()?);
+
+// or
+
+f(a.try_into().expect("Unexpected u16 overflow in f"));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/as_underscore.txt b/src/tools/clippy/src/docs/as_underscore.txt
new file mode 100644
index 000000000000..2d9b0c358936
--- /dev/null
+++ b/src/tools/clippy/src/docs/as_underscore.txt
@@ -0,0 +1,21 @@
+### What it does
+Check for the usage of `as _` conversion using inferred type.
+
+### Why is this bad?
+The conversion might include lossy conversion and dangerous cast that might go
+undetected due to the type being inferred.
+
+The lint is allowed by default as using `_` is less wordy than always specifying the type.
+
+### Example
+```
+fn foo(n: usize) {}
+let n: u16 = 256;
+foo(n as _);
+```
+Use instead:
+```
+fn foo(n: usize) {}
+let n: u16 = 256;
+foo(n as usize);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/assertions_on_constants.txt b/src/tools/clippy/src/docs/assertions_on_constants.txt
new file mode 100644
index 000000000000..270c1e3b639d
--- /dev/null
+++ b/src/tools/clippy/src/docs/assertions_on_constants.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for `assert!(true)` and `assert!(false)` calls.
+
+### Why is this bad?
+Will be optimized out by the compiler or should probably be replaced by a
+`panic!()` or `unreachable!()`
+
+### Example
+```
+assert!(false)
+assert!(true)
+const B: bool = false;
+assert!(B)
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/assertions_on_result_states.txt b/src/tools/clippy/src/docs/assertions_on_result_states.txt
new file mode 100644
index 000000000000..0889084fd3ad
--- /dev/null
+++ b/src/tools/clippy/src/docs/assertions_on_result_states.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for `assert!(r.is_ok())` or `assert!(r.is_err())` calls.
+
+### Why is this bad?
+An assertion failure cannot output an useful message of the error.
+
+### Known problems
+The suggested replacement decreases the readability of code and log output.
+
+### Example
+```
+assert!(r.is_ok());
+assert!(r.is_err());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/assign_op_pattern.txt b/src/tools/clippy/src/docs/assign_op_pattern.txt
new file mode 100644
index 000000000000..f355c0cc18d3
--- /dev/null
+++ b/src/tools/clippy/src/docs/assign_op_pattern.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for `a = a op b` or `a = b commutative_op a`
+patterns.
+
+### Why is this bad?
+These can be written as the shorter `a op= b`.
+
+### Known problems
+While forbidden by the spec, `OpAssign` traits may have
+implementations that differ from the regular `Op` impl.
+
+### Example
+```
+let mut a = 5;
+let b = 0;
+// ...
+
+a = a + b;
+```
+
+Use instead:
+```
+let mut a = 5;
+let b = 0;
+// ...
+
+a += b;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/async_yields_async.txt b/src/tools/clippy/src/docs/async_yields_async.txt
new file mode 100644
index 000000000000..a40de6d2e473
--- /dev/null
+++ b/src/tools/clippy/src/docs/async_yields_async.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for async blocks that yield values of types
+that can themselves be awaited.
+
+### Why is this bad?
+An await is likely missing.
+
+### Example
+```
+async fn foo() {}
+
+fn bar() {
+  let x = async {
+    foo()
+  };
+}
+```
+
+Use instead:
+```
+async fn foo() {}
+
+fn bar() {
+  let x = async {
+    foo().await
+  };
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/await_holding_invalid_type.txt b/src/tools/clippy/src/docs/await_holding_invalid_type.txt
new file mode 100644
index 000000000000..e9c768772ff6
--- /dev/null
+++ b/src/tools/clippy/src/docs/await_holding_invalid_type.txt
@@ -0,0 +1,29 @@
+### What it does
+Allows users to configure types which should not be held across `await`
+suspension points.
+
+### Why is this bad?
+There are some types which are perfectly "safe" to be used concurrently
+from a memory access perspective but will cause bugs at runtime if they
+are held in such a way.
+
+### Example
+
+```
+await-holding-invalid-types = [
+  # You can specify a type name
+  "CustomLockType",
+  # You can (optionally) specify a reason
+  { path = "OtherCustomLockType", reason = "Relies on a thread local" }
+]
+```
+
+```
+struct CustomLockType;
+struct OtherCustomLockType;
+async fn foo() {
+  let _x = CustomLockType;
+  let _y = OtherCustomLockType;
+  baz().await; // Lint violation
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/await_holding_lock.txt b/src/tools/clippy/src/docs/await_holding_lock.txt
new file mode 100644
index 000000000000..0f450a11160c
--- /dev/null
+++ b/src/tools/clippy/src/docs/await_holding_lock.txt
@@ -0,0 +1,51 @@
+### What it does
+Checks for calls to await while holding a non-async-aware MutexGuard.
+
+### Why is this bad?
+The Mutex types found in std::sync and parking_lot
+are not designed to operate in an async context across await points.
+
+There are two potential solutions. One is to use an async-aware Mutex
+type. Many asynchronous foundation crates provide such a Mutex type. The
+other solution is to ensure the mutex is unlocked before calling await,
+either by introducing a scope or an explicit call to Drop::drop.
+
+### Known problems
+Will report false positive for explicitly dropped guards
+([#6446](https://github.com/rust-lang/rust-clippy/issues/6446)). A workaround for this is
+to wrap the `.lock()` call in a block instead of explicitly dropping the guard.
+
+### Example
+```
+async fn foo(x: &Mutex<u32>) {
+  let mut guard = x.lock().unwrap();
+  *guard += 1;
+  baz().await;
+}
+
+async fn bar(x: &Mutex<u32>) {
+  let mut guard = x.lock().unwrap();
+  *guard += 1;
+  drop(guard); // explicit drop
+  baz().await;
+}
+```
+
+Use instead:
+```
+async fn foo(x: &Mutex<u32>) {
+  {
+    let mut guard = x.lock().unwrap();
+    *guard += 1;
+  }
+  baz().await;
+}
+
+async fn bar(x: &Mutex<u32>) {
+  {
+    let mut guard = x.lock().unwrap();
+    *guard += 1;
+  } // guard dropped here at end of scope
+  baz().await;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/await_holding_refcell_ref.txt b/src/tools/clippy/src/docs/await_holding_refcell_ref.txt
new file mode 100644
index 000000000000..226a261b9cc5
--- /dev/null
+++ b/src/tools/clippy/src/docs/await_holding_refcell_ref.txt
@@ -0,0 +1,47 @@
+### What it does
+Checks for calls to await while holding a `RefCell` `Ref` or `RefMut`.
+
+### Why is this bad?
+`RefCell` refs only check for exclusive mutable access
+at runtime. Holding onto a `RefCell` ref across an `await` suspension point
+risks panics from a mutable ref shared while other refs are outstanding.
+
+### Known problems
+Will report false positive for explicitly dropped refs
+([#6353](https://github.com/rust-lang/rust-clippy/issues/6353)). A workaround for this is
+to wrap the `.borrow[_mut]()` call in a block instead of explicitly dropping the ref.
+
+### Example
+```
+async fn foo(x: &RefCell<u32>) {
+  let mut y = x.borrow_mut();
+  *y += 1;
+  baz().await;
+}
+
+async fn bar(x: &RefCell<u32>) {
+  let mut y = x.borrow_mut();
+  *y += 1;
+  drop(y); // explicit drop
+  baz().await;
+}
+```
+
+Use instead:
+```
+async fn foo(x: &RefCell<u32>) {
+  {
+     let mut y = x.borrow_mut();
+     *y += 1;
+  }
+  baz().await;
+}
+
+async fn bar(x: &RefCell<u32>) {
+  {
+    let mut y = x.borrow_mut();
+    *y += 1;
+  } // y dropped here at end of scope
+  baz().await;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bad_bit_mask.txt b/src/tools/clippy/src/docs/bad_bit_mask.txt
new file mode 100644
index 000000000000..d40024ee5620
--- /dev/null
+++ b/src/tools/clippy/src/docs/bad_bit_mask.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for incompatible bit masks in comparisons.
+
+The formula for detecting if an expression of the type `_ <bit_op> m
+<cmp_op> c` (where `<bit_op>` is one of {`&`, `|`} and `<cmp_op>` is one of
+{`!=`, `>=`, `>`, `!=`, `>=`, `>`}) can be determined from the following
+table:
+
+|Comparison  |Bit Op|Example      |is always|Formula               |
+|------------|------|-------------|---------|----------------------|
+|`==` or `!=`| `&`  |`x & 2 == 3` |`false`  |`c & m != c`          |
+|`<`  or `>=`| `&`  |`x & 2 < 3`  |`true`   |`m < c`               |
+|`>`  or `<=`| `&`  |`x & 1 > 1`  |`false`  |`m <= c`              |
+|`==` or `!=`| `\|` |`x \| 1 == 0`|`false`  |`c \| m != c`         |
+|`<`  or `>=`| `\|` |`x \| 1 < 1` |`false`  |`m >= c`              |
+|`<=` or `>` | `\|` |`x \| 1 > 0` |`true`   |`m > c`               |
+
+### Why is this bad?
+If the bits that the comparison cares about are always
+set to zero or one by the bit mask, the comparison is constant `true` or
+`false` (depending on mask, compared value, and operators).
+
+So the code is actively misleading, and the only reason someone would write
+this intentionally is to win an underhanded Rust contest or create a
+test-case for this lint.
+
+### Example
+```
+if (x & 1 == 2) { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bind_instead_of_map.txt b/src/tools/clippy/src/docs/bind_instead_of_map.txt
new file mode 100644
index 000000000000..148575803d38
--- /dev/null
+++ b/src/tools/clippy/src/docs/bind_instead_of_map.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usage of `_.and_then(|x| Some(y))`, `_.and_then(|x| Ok(y))` or
+`_.or_else(|x| Err(y))`.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.map(|x| y)` or `_.map_err(|x| y)`.
+
+### Example
+```
+let _ = opt().and_then(|s| Some(s.len()));
+let _ = res().and_then(|s| if s.len() == 42 { Ok(10) } else { Ok(20) });
+let _ = res().or_else(|s| if s.len() == 42 { Err(10) } else { Err(20) });
+```
+
+The correct use would be:
+
+```
+let _ = opt().map(|s| s.len());
+let _ = res().map(|s| if s.len() == 42 { 10 } else { 20 });
+let _ = res().map_err(|s| if s.len() == 42 { 10 } else { 20 });
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/blanket_clippy_restriction_lints.txt b/src/tools/clippy/src/docs/blanket_clippy_restriction_lints.txt
new file mode 100644
index 000000000000..28a4ebf7169b
--- /dev/null
+++ b/src/tools/clippy/src/docs/blanket_clippy_restriction_lints.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for `warn`/`deny`/`forbid` attributes targeting the whole clippy::restriction category.
+
+### Why is this bad?
+Restriction lints sometimes are in contrast with other lints or even go against idiomatic rust.
+These lints should only be enabled on a lint-by-lint basis and with careful consideration.
+
+### Example
+```
+#![deny(clippy::restriction)]
+```
+
+Use instead:
+```
+#![deny(clippy::as_conversions)]
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/blocks_in_if_conditions.txt b/src/tools/clippy/src/docs/blocks_in_if_conditions.txt
new file mode 100644
index 000000000000..3afa14853fd2
--- /dev/null
+++ b/src/tools/clippy/src/docs/blocks_in_if_conditions.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for `if` conditions that use blocks containing an
+expression, statements or conditions that use closures with blocks.
+
+### Why is this bad?
+Style, using blocks in the condition makes it hard to read.
+
+### Examples
+```
+if { true } { /* ... */ }
+
+if { let x = somefunc(); x } { /* ... */ }
+```
+
+Use instead:
+```
+if true { /* ... */ }
+
+let res = { let x = somefunc(); x };
+if res { /* ... */ }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bool_assert_comparison.txt b/src/tools/clippy/src/docs/bool_assert_comparison.txt
new file mode 100644
index 000000000000..df7ca00cc2ba
--- /dev/null
+++ b/src/tools/clippy/src/docs/bool_assert_comparison.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint warns about boolean comparisons in assert-like macros.
+
+### Why is this bad?
+It is shorter to use the equivalent.
+
+### Example
+```
+assert_eq!("a".is_empty(), false);
+assert_ne!("a".is_empty(), true);
+```
+
+Use instead:
+```
+assert!(!"a".is_empty());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bool_comparison.txt b/src/tools/clippy/src/docs/bool_comparison.txt
new file mode 100644
index 000000000000..0996f60cec44
--- /dev/null
+++ b/src/tools/clippy/src/docs/bool_comparison.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for expressions of the form `x == true`,
+`x != true` and order comparisons such as `x < true` (or vice versa) and
+suggest using the variable directly.
+
+### Why is this bad?
+Unnecessary code.
+
+### Example
+```
+if x == true {}
+if y == false {}
+```
+use `x` directly:
+```
+if x {}
+if !y {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bool_to_int_with_if.txt b/src/tools/clippy/src/docs/bool_to_int_with_if.txt
new file mode 100644
index 000000000000..63535b454c9f
--- /dev/null
+++ b/src/tools/clippy/src/docs/bool_to_int_with_if.txt
@@ -0,0 +1,26 @@
+### What it does
+Instead of using an if statement to convert a bool to an int,
+this lint suggests using a `from()` function or an `as` coercion.
+
+### Why is this bad?
+Coercion or `from()` is idiomatic way to convert bool to a number.
+Both methods are guaranteed to return 1 for true, and 0 for false.
+
+See https://doc.rust-lang.org/std/primitive.bool.html#impl-From%3Cbool%3E
+
+### Example
+```
+if condition {
+    1_i64
+} else {
+    0
+};
+```
+Use instead:
+```
+i64::from(condition);
+```
+or
+```
+condition as i64;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/borrow_as_ptr.txt b/src/tools/clippy/src/docs/borrow_as_ptr.txt
new file mode 100644
index 000000000000..0be865abd578
--- /dev/null
+++ b/src/tools/clippy/src/docs/borrow_as_ptr.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for the usage of `&expr as *const T` or
+`&mut expr as *mut T`, and suggest using `ptr::addr_of` or
+`ptr::addr_of_mut` instead.
+
+### Why is this bad?
+This would improve readability and avoid creating a reference
+that points to an uninitialized value or unaligned place.
+Read the `ptr::addr_of` docs for more information.
+
+### Example
+```
+let val = 1;
+let p = &val as *const i32;
+
+let mut val_mut = 1;
+let p_mut = &mut val_mut as *mut i32;
+```
+Use instead:
+```
+let val = 1;
+let p = std::ptr::addr_of!(val);
+
+let mut val_mut = 1;
+let p_mut = std::ptr::addr_of_mut!(val_mut);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/borrow_deref_ref.txt b/src/tools/clippy/src/docs/borrow_deref_ref.txt
new file mode 100644
index 000000000000..352480d3f26a
--- /dev/null
+++ b/src/tools/clippy/src/docs/borrow_deref_ref.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for `&*(&T)`.
+
+### Why is this bad?
+Dereferencing and then borrowing a reference value has no effect in most cases.
+
+### Known problems
+False negative on such code:
+```
+let x = &12;
+let addr_x = &x as *const _ as usize;
+let addr_y = &&*x as *const _ as usize; // assert ok now, and lint triggered.
+                                        // But if we fix it, assert will fail.
+assert_ne!(addr_x, addr_y);
+```
+
+### Example
+```
+let s = &String::new();
+
+let a: &String = &* s;
+```
+
+Use instead:
+```
+let a: &String = s;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/borrow_interior_mutable_const.txt b/src/tools/clippy/src/docs/borrow_interior_mutable_const.txt
new file mode 100644
index 000000000000..e55b6a77e666
--- /dev/null
+++ b/src/tools/clippy/src/docs/borrow_interior_mutable_const.txt
@@ -0,0 +1,40 @@
+### What it does
+Checks if `const` items which is interior mutable (e.g.,
+contains a `Cell`, `Mutex`, `AtomicXxxx`, etc.) has been borrowed directly.
+
+### Why is this bad?
+Consts are copied everywhere they are referenced, i.e.,
+every time you refer to the const a fresh instance of the `Cell` or `Mutex`
+or `AtomicXxxx` will be created, which defeats the whole purpose of using
+these types in the first place.
+
+The `const` value should be stored inside a `static` item.
+
+### Known problems
+When an enum has variants with interior mutability, use of its non
+interior mutable variants can generate false positives. See issue
+[#3962](https://github.com/rust-lang/rust-clippy/issues/3962)
+
+Types that have underlying or potential interior mutability trigger the lint whether
+the interior mutable field is used or not. See issues
+[#5812](https://github.com/rust-lang/rust-clippy/issues/5812) and
+[#3825](https://github.com/rust-lang/rust-clippy/issues/3825)
+
+### Example
+```
+use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
+const CONST_ATOM: AtomicUsize = AtomicUsize::new(12);
+
+CONST_ATOM.store(6, SeqCst); // the content of the atomic is unchanged
+assert_eq!(CONST_ATOM.load(SeqCst), 12); // because the CONST_ATOM in these lines are distinct
+```
+
+Use instead:
+```
+use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
+const CONST_ATOM: AtomicUsize = AtomicUsize::new(12);
+
+static STATIC_ATOM: AtomicUsize = CONST_ATOM;
+STATIC_ATOM.store(9, SeqCst);
+assert_eq!(STATIC_ATOM.load(SeqCst), 9); // use a `static` item to refer to the same instance
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/borrowed_box.txt b/src/tools/clippy/src/docs/borrowed_box.txt
new file mode 100644
index 000000000000..d7089be662a5
--- /dev/null
+++ b/src/tools/clippy/src/docs/borrowed_box.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for use of `&Box<T>` anywhere in the code.
+Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
+
+### Why is this bad?
+A `&Box<T>` parameter requires the function caller to box `T` first before passing it to a function.
+Using `&T` defines a concrete type for the parameter and generalizes the function, this would also
+auto-deref to `&T` at the function call site if passed a `&Box<T>`.
+
+### Example
+```
+fn foo(bar: &Box<T>) { ... }
+```
+
+Better:
+
+```
+fn foo(bar: &T) { ... }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/box_collection.txt b/src/tools/clippy/src/docs/box_collection.txt
new file mode 100644
index 000000000000..053f24c46281
--- /dev/null
+++ b/src/tools/clippy/src/docs/box_collection.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for use of `Box<T>` where T is a collection such as Vec anywhere in the code.
+Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
+
+### Why is this bad?
+Collections already keeps their contents in a separate area on
+the heap. So if you `Box` them, you just add another level of indirection
+without any benefit whatsoever.
+
+### Example
+```
+struct X {
+    values: Box<Vec<Foo>>,
+}
+```
+
+Better:
+
+```
+struct X {
+    values: Vec<Foo>,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/boxed_local.txt b/src/tools/clippy/src/docs/boxed_local.txt
new file mode 100644
index 000000000000..8b1febf1455f
--- /dev/null
+++ b/src/tools/clippy/src/docs/boxed_local.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for usage of `Box<T>` where an unboxed `T` would
+work fine.
+
+### Why is this bad?
+This is an unnecessary allocation, and bad for
+performance. It is only necessary to allocate if you wish to move the box
+into something.
+
+### Example
+```
+fn foo(x: Box<u32>) {}
+```
+
+Use instead:
+```
+fn foo(x: u32) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/branches_sharing_code.txt b/src/tools/clippy/src/docs/branches_sharing_code.txt
new file mode 100644
index 000000000000..79be6124798a
--- /dev/null
+++ b/src/tools/clippy/src/docs/branches_sharing_code.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks if the `if` and `else` block contain shared code that can be
+moved out of the blocks.
+
+### Why is this bad?
+Duplicate code is less maintainable.
+
+### Known problems
+* The lint doesn't check if the moved expressions modify values that are being used in
+  the if condition. The suggestion can in that case modify the behavior of the program.
+  See [rust-clippy#7452](https://github.com/rust-lang/rust-clippy/issues/7452)
+
+### Example
+```
+let foo = if … {
+    println!("Hello World");
+    13
+} else {
+    println!("Hello World");
+    42
+};
+```
+
+Use instead:
+```
+println!("Hello World");
+let foo = if … {
+    13
+} else {
+    42
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/builtin_type_shadow.txt b/src/tools/clippy/src/docs/builtin_type_shadow.txt
new file mode 100644
index 000000000000..15b1c9df7baa
--- /dev/null
+++ b/src/tools/clippy/src/docs/builtin_type_shadow.txt
@@ -0,0 +1,15 @@
+### What it does
+Warns if a generic shadows a built-in type.
+
+### Why is this bad?
+This gives surprising type errors.
+
+### Example
+
+```
+impl<u32> Foo<u32> {
+    fn impl_func(&self) -> u32 {
+        42
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bytes_count_to_len.txt b/src/tools/clippy/src/docs/bytes_count_to_len.txt
new file mode 100644
index 000000000000..ca7bf9a38da8
--- /dev/null
+++ b/src/tools/clippy/src/docs/bytes_count_to_len.txt
@@ -0,0 +1,18 @@
+### What it does
+It checks for `str::bytes().count()` and suggests replacing it with
+`str::len()`.
+
+### Why is this bad?
+`str::bytes().count()` is longer and may not be as performant as using
+`str::len()`.
+
+### Example
+```
+"hello".bytes().count();
+String::from("hello").bytes().count();
+```
+Use instead:
+```
+"hello".len();
+String::from("hello").len();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/bytes_nth.txt b/src/tools/clippy/src/docs/bytes_nth.txt
new file mode 100644
index 000000000000..260de343353d
--- /dev/null
+++ b/src/tools/clippy/src/docs/bytes_nth.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for the use of `.bytes().nth()`.
+
+### Why is this bad?
+`.as_bytes().get()` is more efficient and more
+readable.
+
+### Example
+```
+"Hello".bytes().nth(3);
+```
+
+Use instead:
+```
+"Hello".as_bytes().get(3);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cargo_common_metadata.txt b/src/tools/clippy/src/docs/cargo_common_metadata.txt
new file mode 100644
index 000000000000..1998647a9274
--- /dev/null
+++ b/src/tools/clippy/src/docs/cargo_common_metadata.txt
@@ -0,0 +1,33 @@
+### What it does
+Checks to see if all common metadata is defined in
+`Cargo.toml`. See: https://rust-lang-nursery.github.io/api-guidelines/documentation.html#cargotoml-includes-all-common-metadata-c-metadata
+
+### Why is this bad?
+It will be more difficult for users to discover the
+purpose of the crate, and key information related to it.
+
+### Example
+```
+[package]
+name = "clippy"
+version = "0.0.212"
+repository = "https://github.com/rust-lang/rust-clippy"
+readme = "README.md"
+license = "MIT OR Apache-2.0"
+keywords = ["clippy", "lint", "plugin"]
+categories = ["development-tools", "development-tools::cargo-plugins"]
+```
+
+Should include a description field like:
+
+```
+[package]
+name = "clippy"
+version = "0.0.212"
+description = "A bunch of helpful lints to avoid common pitfalls in Rust"
+repository = "https://github.com/rust-lang/rust-clippy"
+readme = "README.md"
+license = "MIT OR Apache-2.0"
+keywords = ["clippy", "lint", "plugin"]
+categories = ["development-tools", "development-tools::cargo-plugins"]
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/case_sensitive_file_extension_comparisons.txt b/src/tools/clippy/src/docs/case_sensitive_file_extension_comparisons.txt
new file mode 100644
index 000000000000..8e6e18ed4e23
--- /dev/null
+++ b/src/tools/clippy/src/docs/case_sensitive_file_extension_comparisons.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for calls to `ends_with` with possible file extensions
+and suggests to use a case-insensitive approach instead.
+
+### Why is this bad?
+`ends_with` is case-sensitive and may not detect files with a valid extension.
+
+### Example
+```
+fn is_rust_file(filename: &str) -> bool {
+    filename.ends_with(".rs")
+}
+```
+Use instead:
+```
+fn is_rust_file(filename: &str) -> bool {
+    let filename = std::path::Path::new(filename);
+    filename.extension()
+        .map_or(false, |ext| ext.eq_ignore_ascii_case("rs"))
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_abs_to_unsigned.txt b/src/tools/clippy/src/docs/cast_abs_to_unsigned.txt
new file mode 100644
index 000000000000..c5d8ee034ce5
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_abs_to_unsigned.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for uses of the `abs()` method that cast the result to unsigned.
+
+### Why is this bad?
+The `unsigned_abs()` method avoids panic when called on the MIN value.
+
+### Example
+```
+let x: i32 = -42;
+let y: u32 = x.abs() as u32;
+```
+Use instead:
+```
+let x: i32 = -42;
+let y: u32 = x.unsigned_abs();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_enum_constructor.txt b/src/tools/clippy/src/docs/cast_enum_constructor.txt
new file mode 100644
index 000000000000..675c03a42bc2
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_enum_constructor.txt
@@ -0,0 +1,11 @@
+### What it does
+Checks for casts from an enum tuple constructor to an integer.
+
+### Why is this bad?
+The cast is easily confused with casting a c-like enum value to an integer.
+
+### Example
+```
+enum E { X(i32) };
+let _ = E::X as usize;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_enum_truncation.txt b/src/tools/clippy/src/docs/cast_enum_truncation.txt
new file mode 100644
index 000000000000..abe32a8296da
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_enum_truncation.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for casts from an enum type to an integral type which will definitely truncate the
+value.
+
+### Why is this bad?
+The resulting integral value will not match the value of the variant it came from.
+
+### Example
+```
+enum E { X = 256 };
+let _ = E::X as u8;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_lossless.txt b/src/tools/clippy/src/docs/cast_lossless.txt
new file mode 100644
index 000000000000..c3a61dd470fc
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_lossless.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for casts between numerical types that may
+be replaced by safe conversion functions.
+
+### Why is this bad?
+Rust's `as` keyword will perform many kinds of
+conversions, including silently lossy conversions. Conversion functions such
+as `i32::from` will only perform lossless conversions. Using the conversion
+functions prevents conversions from turning into silent lossy conversions if
+the types of the input expressions ever change, and make it easier for
+people reading the code to know that the conversion is lossless.
+
+### Example
+```
+fn as_u64(x: u8) -> u64 {
+    x as u64
+}
+```
+
+Using `::from` would look like this:
+
+```
+fn as_u64(x: u8) -> u64 {
+    u64::from(x)
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_possible_truncation.txt b/src/tools/clippy/src/docs/cast_possible_truncation.txt
new file mode 100644
index 000000000000..0b164848cc7c
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_possible_truncation.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for casts between numerical types that may
+truncate large values. This is expected behavior, so the cast is `Allow` by
+default.
+
+### Why is this bad?
+In some problem domains, it is good practice to avoid
+truncation. This lint can be activated to help assess where additional
+checks could be beneficial.
+
+### Example
+```
+fn as_u8(x: u64) -> u8 {
+    x as u8
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_possible_wrap.txt b/src/tools/clippy/src/docs/cast_possible_wrap.txt
new file mode 100644
index 000000000000..f883fc9cfb99
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_possible_wrap.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for casts from an unsigned type to a signed type of
+the same size. Performing such a cast is a 'no-op' for the compiler,
+i.e., nothing is changed at the bit level, and the binary representation of
+the value is reinterpreted. This can cause wrapping if the value is too big
+for the target signed type. However, the cast works as defined, so this lint
+is `Allow` by default.
+
+### Why is this bad?
+While such a cast is not bad in itself, the results can
+be surprising when this is not the intended behavior, as demonstrated by the
+example below.
+
+### Example
+```
+u32::MAX as i32; // will yield a value of `-1`
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_precision_loss.txt b/src/tools/clippy/src/docs/cast_precision_loss.txt
new file mode 100644
index 000000000000..f915d9f8a6d0
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_precision_loss.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for casts from any numerical to a float type where
+the receiving type cannot store all values from the original type without
+rounding errors. This possible rounding is to be expected, so this lint is
+`Allow` by default.
+
+Basically, this warns on casting any integer with 32 or more bits to `f32`
+or any 64-bit integer to `f64`.
+
+### Why is this bad?
+It's not bad at all. But in some applications it can be
+helpful to know where precision loss can take place. This lint can help find
+those places in the code.
+
+### Example
+```
+let x = u64::MAX;
+x as f64;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_ptr_alignment.txt b/src/tools/clippy/src/docs/cast_ptr_alignment.txt
new file mode 100644
index 000000000000..6a6d4dcaa2ae
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_ptr_alignment.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for casts, using `as` or `pointer::cast`,
+from a less-strictly-aligned pointer to a more-strictly-aligned pointer
+
+### Why is this bad?
+Dereferencing the resulting pointer may be undefined
+behavior.
+
+### Known problems
+Using `std::ptr::read_unaligned` and `std::ptr::write_unaligned` or similar
+on the resulting pointer is fine. Is over-zealous: Casts with manual alignment checks or casts like
+u64-> u8 -> u16 can be fine. Miri is able to do a more in-depth analysis.
+
+### Example
+```
+let _ = (&1u8 as *const u8) as *const u16;
+let _ = (&mut 1u8 as *mut u8) as *mut u16;
+
+(&1u8 as *const u8).cast::<u16>();
+(&mut 1u8 as *mut u8).cast::<u16>();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_ref_to_mut.txt b/src/tools/clippy/src/docs/cast_ref_to_mut.txt
new file mode 100644
index 000000000000..fb5b4dbb62d8
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_ref_to_mut.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for casts of `&T` to `&mut T` anywhere in the code.
+
+### Why is this bad?
+It’s basically guaranteed to be undefined behavior.
+`UnsafeCell` is the only way to obtain aliasable data that is considered
+mutable.
+
+### Example
+```
+fn x(r: &i32) {
+    unsafe {
+        *(r as *const _ as *mut _) += 1;
+    }
+}
+```
+
+Instead consider using interior mutability types.
+
+```
+use std::cell::UnsafeCell;
+
+fn x(r: &UnsafeCell<i32>) {
+    unsafe {
+        *r.get() += 1;
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_sign_loss.txt b/src/tools/clippy/src/docs/cast_sign_loss.txt
new file mode 100644
index 000000000000..d64fe1b07f46
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_sign_loss.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for casts from a signed to an unsigned numerical
+type. In this case, negative values wrap around to large positive values,
+which can be quite surprising in practice. However, as the cast works as
+defined, this lint is `Allow` by default.
+
+### Why is this bad?
+Possibly surprising results. You can activate this lint
+as a one-time check to see where numerical wrapping can arise.
+
+### Example
+```
+let y: i8 = -1;
+y as u128; // will return 18446744073709551615
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_slice_different_sizes.txt b/src/tools/clippy/src/docs/cast_slice_different_sizes.txt
new file mode 100644
index 000000000000..c01ef0ba92c0
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_slice_different_sizes.txt
@@ -0,0 +1,38 @@
+### What it does
+Checks for `as` casts between raw pointers to slices with differently sized elements.
+
+### Why is this bad?
+The produced raw pointer to a slice does not update its length metadata. The produced
+pointer will point to a different number of bytes than the original pointer because the
+length metadata of a raw slice pointer is in elements rather than bytes.
+Producing a slice reference from the raw pointer will either create a slice with
+less data (which can be surprising) or create a slice with more data and cause Undefined Behavior.
+
+### Example
+// Missing data
+```
+let a = [1_i32, 2, 3, 4];
+let p = &a as *const [i32] as *const [u8];
+unsafe {
+    println!("{:?}", &*p);
+}
+```
+// Undefined Behavior (note: also potential alignment issues)
+```
+let a = [1_u8, 2, 3, 4];
+let p = &a as *const [u8] as *const [u32];
+unsafe {
+    println!("{:?}", &*p);
+}
+```
+Instead use `ptr::slice_from_raw_parts` to construct a slice from a data pointer and the correct length
+```
+let a = [1_i32, 2, 3, 4];
+let old_ptr = &a as *const [i32];
+// The data pointer is cast to a pointer to the target `u8` not `[u8]`
+// The length comes from the known length of 4 i32s times the 4 bytes per i32
+let new_ptr = core::ptr::slice_from_raw_parts(old_ptr as *const u8, 16);
+unsafe {
+    println!("{:?}", &*new_ptr);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cast_slice_from_raw_parts.txt b/src/tools/clippy/src/docs/cast_slice_from_raw_parts.txt
new file mode 100644
index 000000000000..b58c739766aa
--- /dev/null
+++ b/src/tools/clippy/src/docs/cast_slice_from_raw_parts.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for a raw slice being cast to a slice pointer
+
+### Why is this bad?
+This can result in multiple `&mut` references to the same location when only a pointer is
+required.
+`ptr::slice_from_raw_parts` is a safe alternative that doesn't require
+the same [safety requirements] to be upheld.
+
+### Example
+```
+let _: *const [u8] = std::slice::from_raw_parts(ptr, len) as *const _;
+let _: *mut [u8] = std::slice::from_raw_parts_mut(ptr, len) as *mut _;
+```
+Use instead:
+```
+let _: *const [u8] = std::ptr::slice_from_raw_parts(ptr, len);
+let _: *mut [u8] = std::ptr::slice_from_raw_parts_mut(ptr, len);
+```
+[safety requirements]: https://doc.rust-lang.org/std/slice/fn.from_raw_parts.html#safety
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/char_lit_as_u8.txt b/src/tools/clippy/src/docs/char_lit_as_u8.txt
new file mode 100644
index 000000000000..00d60b9a451b
--- /dev/null
+++ b/src/tools/clippy/src/docs/char_lit_as_u8.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for expressions where a character literal is cast
+to `u8` and suggests using a byte literal instead.
+
+### Why is this bad?
+In general, casting values to smaller types is
+error-prone and should be avoided where possible. In the particular case of
+converting a character literal to u8, it is easy to avoid by just using a
+byte literal instead. As an added bonus, `b'a'` is even slightly shorter
+than `'a' as u8`.
+
+### Example
+```
+'x' as u8
+```
+
+A better version, using the byte literal:
+
+```
+b'x'
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/chars_last_cmp.txt b/src/tools/clippy/src/docs/chars_last_cmp.txt
new file mode 100644
index 000000000000..4c1d8838973a
--- /dev/null
+++ b/src/tools/clippy/src/docs/chars_last_cmp.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for usage of `_.chars().last()` or
+`_.chars().next_back()` on a `str` to check if it ends with a given char.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.ends_with(_)`.
+
+### Example
+```
+name.chars().last() == Some('_') || name.chars().next_back() == Some('-');
+```
+
+Use instead:
+```
+name.ends_with('_') || name.ends_with('-');
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/chars_next_cmp.txt b/src/tools/clippy/src/docs/chars_next_cmp.txt
new file mode 100644
index 000000000000..77cbce2de00f
--- /dev/null
+++ b/src/tools/clippy/src/docs/chars_next_cmp.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `.chars().next()` on a `str` to check
+if it starts with a given char.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.starts_with(_)`.
+
+### Example
+```
+let name = "foo";
+if name.chars().next() == Some('_') {};
+```
+
+Use instead:
+```
+let name = "foo";
+if name.starts_with('_') {};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/checked_conversions.txt b/src/tools/clippy/src/docs/checked_conversions.txt
new file mode 100644
index 000000000000..536b01294ee1
--- /dev/null
+++ b/src/tools/clippy/src/docs/checked_conversions.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for explicit bounds checking when casting.
+
+### Why is this bad?
+Reduces the readability of statements & is error prone.
+
+### Example
+```
+foo <= i32::MAX as u32;
+```
+
+Use instead:
+```
+i32::try_from(foo).is_ok();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/clone_double_ref.txt b/src/tools/clippy/src/docs/clone_double_ref.txt
new file mode 100644
index 000000000000..2729635bd246
--- /dev/null
+++ b/src/tools/clippy/src/docs/clone_double_ref.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of `.clone()` on an `&&T`.
+
+### Why is this bad?
+Cloning an `&&T` copies the inner `&T`, instead of
+cloning the underlying `T`.
+
+### Example
+```
+fn main() {
+    let x = vec![1];
+    let y = &&x;
+    let z = y.clone();
+    println!("{:p} {:p}", *y, z); // prints out the same pointer
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/clone_on_copy.txt b/src/tools/clippy/src/docs/clone_on_copy.txt
new file mode 100644
index 000000000000..99a0bdb4c4ac
--- /dev/null
+++ b/src/tools/clippy/src/docs/clone_on_copy.txt
@@ -0,0 +1,11 @@
+### What it does
+Checks for usage of `.clone()` on a `Copy` type.
+
+### Why is this bad?
+The only reason `Copy` types implement `Clone` is for
+generics, not for using the `clone` method on a concrete type.
+
+### Example
+```
+42u64.clone();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/clone_on_ref_ptr.txt b/src/tools/clippy/src/docs/clone_on_ref_ptr.txt
new file mode 100644
index 000000000000..2d83f8fefc12
--- /dev/null
+++ b/src/tools/clippy/src/docs/clone_on_ref_ptr.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for usage of `.clone()` on a ref-counted pointer,
+(`Rc`, `Arc`, `rc::Weak`, or `sync::Weak`), and suggests calling Clone via unified
+function syntax instead (e.g., `Rc::clone(foo)`).
+
+### Why is this bad?
+Calling '.clone()' on an Rc, Arc, or Weak
+can obscure the fact that only the pointer is being cloned, not the underlying
+data.
+
+### Example
+```
+let x = Rc::new(1);
+
+x.clone();
+```
+
+Use instead:
+```
+Rc::clone(&x);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cloned_instead_of_copied.txt b/src/tools/clippy/src/docs/cloned_instead_of_copied.txt
new file mode 100644
index 000000000000..2f2014d5fd29
--- /dev/null
+++ b/src/tools/clippy/src/docs/cloned_instead_of_copied.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usages of `cloned()` on an `Iterator` or `Option` where
+`copied()` could be used instead.
+
+### Why is this bad?
+`copied()` is better because it guarantees that the type being cloned
+implements `Copy`.
+
+### Example
+```
+[1, 2, 3].iter().cloned();
+```
+Use instead:
+```
+[1, 2, 3].iter().copied();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cmp_nan.txt b/src/tools/clippy/src/docs/cmp_nan.txt
new file mode 100644
index 000000000000..e2ad04d93235
--- /dev/null
+++ b/src/tools/clippy/src/docs/cmp_nan.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for comparisons to NaN.
+
+### Why is this bad?
+NaN does not compare meaningfully to anything – not
+even itself – so those comparisons are simply wrong.
+
+### Example
+```
+if x == f32::NAN { }
+```
+
+Use instead:
+```
+if x.is_nan() { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cmp_null.txt b/src/tools/clippy/src/docs/cmp_null.txt
new file mode 100644
index 000000000000..02fd15124f03
--- /dev/null
+++ b/src/tools/clippy/src/docs/cmp_null.txt
@@ -0,0 +1,23 @@
+### What it does
+This lint checks for equality comparisons with `ptr::null`
+
+### Why is this bad?
+It's easier and more readable to use the inherent
+`.is_null()`
+method instead
+
+### Example
+```
+use std::ptr;
+
+if x == ptr::null {
+    // ..
+}
+```
+
+Use instead:
+```
+if x.is_null() {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cmp_owned.txt b/src/tools/clippy/src/docs/cmp_owned.txt
new file mode 100644
index 000000000000..f8d4956ff1d4
--- /dev/null
+++ b/src/tools/clippy/src/docs/cmp_owned.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for conversions to owned values just for the sake
+of a comparison.
+
+### Why is this bad?
+The comparison can operate on a reference, so creating
+an owned value effectively throws it away directly afterwards, which is
+needlessly consuming code and heap space.
+
+### Example
+```
+if x.to_owned() == y {}
+```
+
+Use instead:
+```
+if x == y {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/cognitive_complexity.txt b/src/tools/clippy/src/docs/cognitive_complexity.txt
new file mode 100644
index 000000000000..fdd75f6479cd
--- /dev/null
+++ b/src/tools/clippy/src/docs/cognitive_complexity.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for methods with high cognitive complexity.
+
+### Why is this bad?
+Methods of high cognitive complexity tend to be hard to
+both read and maintain. Also LLVM will tend to optimize small methods better.
+
+### Known problems
+Sometimes it's hard to find a way to reduce the
+complexity.
+
+### Example
+You'll see it when you get the warning.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/collapsible_else_if.txt b/src/tools/clippy/src/docs/collapsible_else_if.txt
new file mode 100644
index 000000000000..4ddfca17731f
--- /dev/null
+++ b/src/tools/clippy/src/docs/collapsible_else_if.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for collapsible `else { if ... }` expressions
+that can be collapsed to `else if ...`.
+
+### Why is this bad?
+Each `if`-statement adds one level of nesting, which
+makes code look more complex than it really is.
+
+### Example
+```
+
+if x {
+    …
+} else {
+    if y {
+        …
+    }
+}
+```
+
+Should be written:
+
+```
+if x {
+    …
+} else if y {
+    …
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/collapsible_if.txt b/src/tools/clippy/src/docs/collapsible_if.txt
new file mode 100644
index 000000000000..e1264ee062e9
--- /dev/null
+++ b/src/tools/clippy/src/docs/collapsible_if.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for nested `if` statements which can be collapsed
+by `&&`-combining their conditions.
+
+### Why is this bad?
+Each `if`-statement adds one level of nesting, which
+makes code look more complex than it really is.
+
+### Example
+```
+if x {
+    if y {
+        // …
+    }
+}
+```
+
+Use instead:
+```
+if x && y {
+    // …
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/collapsible_match.txt b/src/tools/clippy/src/docs/collapsible_match.txt
new file mode 100644
index 000000000000..0d59594a03a2
--- /dev/null
+++ b/src/tools/clippy/src/docs/collapsible_match.txt
@@ -0,0 +1,31 @@
+### What it does
+Finds nested `match` or `if let` expressions where the patterns may be "collapsed" together
+without adding any branches.
+
+Note that this lint is not intended to find _all_ cases where nested match patterns can be merged, but only
+cases where merging would most likely make the code more readable.
+
+### Why is this bad?
+It is unnecessarily verbose and complex.
+
+### Example
+```
+fn func(opt: Option<Result<u64, String>>) {
+    let n = match opt {
+        Some(n) => match n {
+            Ok(n) => n,
+            _ => return,
+        }
+        None => return,
+    };
+}
+```
+Use instead:
+```
+fn func(opt: Option<Result<u64, String>>) {
+    let n = match opt {
+        Some(Ok(n)) => n,
+        _ => return,
+    };
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/collapsible_str_replace.txt b/src/tools/clippy/src/docs/collapsible_str_replace.txt
new file mode 100644
index 000000000000..c24c25a3028a
--- /dev/null
+++ b/src/tools/clippy/src/docs/collapsible_str_replace.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for consecutive calls to `str::replace` (2 or more)
+that can be collapsed into a single call.
+
+### Why is this bad?
+Consecutive `str::replace` calls scan the string multiple times
+with repetitive code.
+
+### Example
+```
+let hello = "hesuo worpd"
+    .replace('s', "l")
+    .replace("u", "l")
+    .replace('p', "l");
+```
+Use instead:
+```
+let hello = "hesuo worpd".replace(&['s', 'u', 'p'], "l");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/comparison_chain.txt b/src/tools/clippy/src/docs/comparison_chain.txt
new file mode 100644
index 000000000000..43b09f31ff4a
--- /dev/null
+++ b/src/tools/clippy/src/docs/comparison_chain.txt
@@ -0,0 +1,36 @@
+### What it does
+Checks comparison chains written with `if` that can be
+rewritten with `match` and `cmp`.
+
+### Why is this bad?
+`if` is not guaranteed to be exhaustive and conditionals can get
+repetitive
+
+### Known problems
+The match statement may be slower due to the compiler
+not inlining the call to cmp. See issue [#5354](https://github.com/rust-lang/rust-clippy/issues/5354)
+
+### Example
+```
+fn f(x: u8, y: u8) {
+    if x > y {
+        a()
+    } else if x < y {
+        b()
+    } else {
+        c()
+    }
+}
+```
+
+Use instead:
+```
+use std::cmp::Ordering;
+fn f(x: u8, y: u8) {
+     match x.cmp(&y) {
+         Ordering::Greater => a(),
+         Ordering::Less => b(),
+         Ordering::Equal => c()
+     }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/comparison_to_empty.txt b/src/tools/clippy/src/docs/comparison_to_empty.txt
new file mode 100644
index 000000000000..db6f74fe2706
--- /dev/null
+++ b/src/tools/clippy/src/docs/comparison_to_empty.txt
@@ -0,0 +1,31 @@
+### What it does
+Checks for comparing to an empty slice such as `""` or `[]`,
+and suggests using `.is_empty()` where applicable.
+
+### Why is this bad?
+Some structures can answer `.is_empty()` much faster
+than checking for equality. So it is good to get into the habit of using
+`.is_empty()`, and having it is cheap.
+Besides, it makes the intent clearer than a manual comparison in some contexts.
+
+### Example
+
+```
+if s == "" {
+    ..
+}
+
+if arr == [] {
+    ..
+}
+```
+Use instead:
+```
+if s.is_empty() {
+    ..
+}
+
+if arr.is_empty() {
+    ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/copy_iterator.txt b/src/tools/clippy/src/docs/copy_iterator.txt
new file mode 100644
index 000000000000..5f9a2a015b86
--- /dev/null
+++ b/src/tools/clippy/src/docs/copy_iterator.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for types that implement `Copy` as well as
+`Iterator`.
+
+### Why is this bad?
+Implicit copies can be confusing when working with
+iterator combinators.
+
+### Example
+```
+#[derive(Copy, Clone)]
+struct Countdown(u8);
+
+impl Iterator for Countdown {
+    // ...
+}
+
+let a: Vec<_> = my_iterator.take(1).collect();
+let b: Vec<_> = my_iterator.collect();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/crate_in_macro_def.txt b/src/tools/clippy/src/docs/crate_in_macro_def.txt
new file mode 100644
index 000000000000..047e986dee71
--- /dev/null
+++ b/src/tools/clippy/src/docs/crate_in_macro_def.txt
@@ -0,0 +1,35 @@
+### What it does
+Checks for use of `crate` as opposed to `$crate` in a macro definition.
+
+### Why is this bad?
+`crate` refers to the macro call's crate, whereas `$crate` refers to the macro definition's
+crate. Rarely is the former intended. See:
+https://doc.rust-lang.org/reference/macros-by-example.html#hygiene
+
+### Example
+```
+#[macro_export]
+macro_rules! print_message {
+    () => {
+        println!("{}", crate::MESSAGE);
+    };
+}
+pub const MESSAGE: &str = "Hello!";
+```
+Use instead:
+```
+#[macro_export]
+macro_rules! print_message {
+    () => {
+        println!("{}", $crate::MESSAGE);
+    };
+}
+pub const MESSAGE: &str = "Hello!";
+```
+
+Note that if the use of `crate` is intentional, an `allow` attribute can be applied to the
+macro definition, e.g.:
+```
+#[allow(clippy::crate_in_macro_def)]
+macro_rules! ok { ... crate::foo ... }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/create_dir.txt b/src/tools/clippy/src/docs/create_dir.txt
new file mode 100644
index 000000000000..e4e7937684e6
--- /dev/null
+++ b/src/tools/clippy/src/docs/create_dir.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks usage of `std::fs::create_dir` and suggest using `std::fs::create_dir_all` instead.
+
+### Why is this bad?
+Sometimes `std::fs::create_dir` is mistakenly chosen over `std::fs::create_dir_all`.
+
+### Example
+```
+std::fs::create_dir("foo");
+```
+
+Use instead:
+```
+std::fs::create_dir_all("foo");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/crosspointer_transmute.txt b/src/tools/clippy/src/docs/crosspointer_transmute.txt
new file mode 100644
index 000000000000..49dea154970e
--- /dev/null
+++ b/src/tools/clippy/src/docs/crosspointer_transmute.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for transmutes between a type `T` and `*T`.
+
+### Why is this bad?
+It's easy to mistakenly transmute between a type and a
+pointer to that type.
+
+### Example
+```
+core::intrinsics::transmute(t) // where the result type is the same as
+                               // `*t` or `&t`'s
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/dbg_macro.txt b/src/tools/clippy/src/docs/dbg_macro.txt
new file mode 100644
index 000000000000..3e1a9a043f9f
--- /dev/null
+++ b/src/tools/clippy/src/docs/dbg_macro.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of dbg!() macro.
+
+### Why is this bad?
+`dbg!` macro is intended as a debugging tool. It
+should not be in version control.
+
+### Example
+```
+dbg!(true)
+```
+
+Use instead:
+```
+true
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/debug_assert_with_mut_call.txt b/src/tools/clippy/src/docs/debug_assert_with_mut_call.txt
new file mode 100644
index 000000000000..2c44abe1f05c
--- /dev/null
+++ b/src/tools/clippy/src/docs/debug_assert_with_mut_call.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for function/method calls with a mutable
+parameter in `debug_assert!`, `debug_assert_eq!` and `debug_assert_ne!` macros.
+
+### Why is this bad?
+In release builds `debug_assert!` macros are optimized out by the
+compiler.
+Therefore mutating something in a `debug_assert!` macro results in different behavior
+between a release and debug build.
+
+### Example
+```
+debug_assert_eq!(vec![3].pop(), Some(3));
+
+// or
+
+debug_assert!(takes_a_mut_parameter(&mut x));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/decimal_literal_representation.txt b/src/tools/clippy/src/docs/decimal_literal_representation.txt
new file mode 100644
index 000000000000..daca9bbb3a84
--- /dev/null
+++ b/src/tools/clippy/src/docs/decimal_literal_representation.txt
@@ -0,0 +1,13 @@
+### What it does
+Warns if there is a better representation for a numeric literal.
+
+### Why is this bad?
+Especially for big powers of 2 a hexadecimal representation is more
+readable than a decimal representation.
+
+### Example
+```
+`255` => `0xFF`
+`65_535` => `0xFFFF`
+`4_042_322_160` => `0xF0F0_F0F0`
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/declare_interior_mutable_const.txt b/src/tools/clippy/src/docs/declare_interior_mutable_const.txt
new file mode 100644
index 000000000000..2801b5ccff80
--- /dev/null
+++ b/src/tools/clippy/src/docs/declare_interior_mutable_const.txt
@@ -0,0 +1,46 @@
+### What it does
+Checks for declaration of `const` items which is interior
+mutable (e.g., contains a `Cell`, `Mutex`, `AtomicXxxx`, etc.).
+
+### Why is this bad?
+Consts are copied everywhere they are referenced, i.e.,
+every time you refer to the const a fresh instance of the `Cell` or `Mutex`
+or `AtomicXxxx` will be created, which defeats the whole purpose of using
+these types in the first place.
+
+The `const` should better be replaced by a `static` item if a global
+variable is wanted, or replaced by a `const fn` if a constructor is wanted.
+
+### Known problems
+A "non-constant" const item is a legacy way to supply an
+initialized value to downstream `static` items (e.g., the
+`std::sync::ONCE_INIT` constant). In this case the use of `const` is legit,
+and this lint should be suppressed.
+
+Even though the lint avoids triggering on a constant whose type has enums that have variants
+with interior mutability, and its value uses non interior mutable variants (see
+[#3962](https://github.com/rust-lang/rust-clippy/issues/3962) and
+[#3825](https://github.com/rust-lang/rust-clippy/issues/3825) for examples);
+it complains about associated constants without default values only based on its types;
+which might not be preferable.
+There're other enums plus associated constants cases that the lint cannot handle.
+
+Types that have underlying or potential interior mutability trigger the lint whether
+the interior mutable field is used or not. See issues
+[#5812](https://github.com/rust-lang/rust-clippy/issues/5812) and
+
+### Example
+```
+use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
+
+const CONST_ATOM: AtomicUsize = AtomicUsize::new(12);
+CONST_ATOM.store(6, SeqCst); // the content of the atomic is unchanged
+assert_eq!(CONST_ATOM.load(SeqCst), 12); // because the CONST_ATOM in these lines are distinct
+```
+
+Use instead:
+```
+static STATIC_ATOM: AtomicUsize = AtomicUsize::new(15);
+STATIC_ATOM.store(9, SeqCst);
+assert_eq!(STATIC_ATOM.load(SeqCst), 9); // use a `static` item to refer to the same instance
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/default_instead_of_iter_empty.txt b/src/tools/clippy/src/docs/default_instead_of_iter_empty.txt
new file mode 100644
index 000000000000..b63ef3d18fc4
--- /dev/null
+++ b/src/tools/clippy/src/docs/default_instead_of_iter_empty.txt
@@ -0,0 +1,15 @@
+### What it does
+It checks for `std::iter::Empty::default()` and suggests replacing it with
+`std::iter::empty()`.
+### Why is this bad?
+`std::iter::empty()` is the more idiomatic way.
+### Example
+```
+let _ = std::iter::Empty::<usize>::default();
+let iter: std::iter::Empty<usize> = std::iter::Empty::default();
+```
+Use instead:
+```
+let _ = std::iter::empty::<usize>();
+let iter: std::iter::Empty<usize> = std::iter::empty();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/default_numeric_fallback.txt b/src/tools/clippy/src/docs/default_numeric_fallback.txt
new file mode 100644
index 000000000000..15076a0a68bf
--- /dev/null
+++ b/src/tools/clippy/src/docs/default_numeric_fallback.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for usage of unconstrained numeric literals which may cause default numeric fallback in type
+inference.
+
+Default numeric fallback means that if numeric types have not yet been bound to concrete
+types at the end of type inference, then integer type is bound to `i32`, and similarly
+floating type is bound to `f64`.
+
+See [RFC0212](https://github.com/rust-lang/rfcs/blob/master/text/0212-restore-int-fallback.md) for more information about the fallback.
+
+### Why is this bad?
+For those who are very careful about types, default numeric fallback
+can be a pitfall that cause unexpected runtime behavior.
+
+### Known problems
+This lint can only be allowed at the function level or above.
+
+### Example
+```
+let i = 10;
+let f = 1.23;
+```
+
+Use instead:
+```
+let i = 10i32;
+let f = 1.23f64;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/default_trait_access.txt b/src/tools/clippy/src/docs/default_trait_access.txt
new file mode 100644
index 000000000000..e69298969c8e
--- /dev/null
+++ b/src/tools/clippy/src/docs/default_trait_access.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for literal calls to `Default::default()`.
+
+### Why is this bad?
+It's easier for the reader if the name of the type is used, rather than the
+generic `Default`.
+
+### Example
+```
+let s: String = Default::default();
+```
+
+Use instead:
+```
+let s = String::default();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/default_union_representation.txt b/src/tools/clippy/src/docs/default_union_representation.txt
new file mode 100644
index 000000000000..f79ff9760e57
--- /dev/null
+++ b/src/tools/clippy/src/docs/default_union_representation.txt
@@ -0,0 +1,36 @@
+### What it does
+Displays a warning when a union is declared with the default representation (without a `#[repr(C)]` attribute).
+
+### Why is this bad?
+Unions in Rust have unspecified layout by default, despite many people thinking that they
+lay out each field at the start of the union (like C does). That is, there are no guarantees
+about the offset of the fields for unions with multiple non-ZST fields without an explicitly
+specified layout. These cases may lead to undefined behavior in unsafe blocks.
+
+### Example
+```
+union Foo {
+    a: i32,
+    b: u32,
+}
+
+fn main() {
+    let _x: u32 = unsafe {
+        Foo { a: 0_i32 }.b // Undefined behavior: `b` is allowed to be padding
+    };
+}
+```
+Use instead:
+```
+#[repr(C)]
+union Foo {
+    a: i32,
+    b: u32,
+}
+
+fn main() {
+    let _x: u32 = unsafe {
+        Foo { a: 0_i32 }.b // Now defined behavior, this is just an i32 -> u32 transmute
+    };
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/deprecated_cfg_attr.txt b/src/tools/clippy/src/docs/deprecated_cfg_attr.txt
new file mode 100644
index 000000000000..9f264887a057
--- /dev/null
+++ b/src/tools/clippy/src/docs/deprecated_cfg_attr.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for `#[cfg_attr(rustfmt, rustfmt_skip)]` and suggests to replace it
+with `#[rustfmt::skip]`.
+
+### Why is this bad?
+Since tool_attributes ([rust-lang/rust#44690](https://github.com/rust-lang/rust/issues/44690))
+are stable now, they should be used instead of the old `cfg_attr(rustfmt)` attributes.
+
+### Known problems
+This lint doesn't detect crate level inner attributes, because they get
+processed before the PreExpansionPass lints get executed. See
+[#3123](https://github.com/rust-lang/rust-clippy/pull/3123#issuecomment-422321765)
+
+### Example
+```
+#[cfg_attr(rustfmt, rustfmt_skip)]
+fn main() { }
+```
+
+Use instead:
+```
+#[rustfmt::skip]
+fn main() { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/deprecated_semver.txt b/src/tools/clippy/src/docs/deprecated_semver.txt
new file mode 100644
index 000000000000..c9574a99b2be
--- /dev/null
+++ b/src/tools/clippy/src/docs/deprecated_semver.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for `#[deprecated]` annotations with a `since`
+field that is not a valid semantic version.
+
+### Why is this bad?
+For checking the version of the deprecation, it must be
+a valid semver. Failing that, the contained information is useless.
+
+### Example
+```
+#[deprecated(since = "forever")]
+fn something_else() { /* ... */ }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/deref_addrof.txt b/src/tools/clippy/src/docs/deref_addrof.txt
new file mode 100644
index 000000000000..fa711b924d48
--- /dev/null
+++ b/src/tools/clippy/src/docs/deref_addrof.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usage of `*&` and `*&mut` in expressions.
+
+### Why is this bad?
+Immediately dereferencing a reference is no-op and
+makes the code less clear.
+
+### Known problems
+Multiple dereference/addrof pairs are not handled so
+the suggested fix for `x = **&&y` is `x = *&y`, which is still incorrect.
+
+### Example
+```
+let a = f(*&mut b);
+let c = *&d;
+```
+
+Use instead:
+```
+let a = f(b);
+let c = d;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/deref_by_slicing.txt b/src/tools/clippy/src/docs/deref_by_slicing.txt
new file mode 100644
index 000000000000..4dad24ac00ca
--- /dev/null
+++ b/src/tools/clippy/src/docs/deref_by_slicing.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for slicing expressions which are equivalent to dereferencing the
+value.
+
+### Why is this bad?
+Some people may prefer to dereference rather than slice.
+
+### Example
+```
+let vec = vec![1, 2, 3];
+let slice = &vec[..];
+```
+Use instead:
+```
+let vec = vec![1, 2, 3];
+let slice = &*vec;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/derivable_impls.txt b/src/tools/clippy/src/docs/derivable_impls.txt
new file mode 100644
index 000000000000..5cee43956cc3
--- /dev/null
+++ b/src/tools/clippy/src/docs/derivable_impls.txt
@@ -0,0 +1,35 @@
+### What it does
+Detects manual `std::default::Default` implementations that are identical to a derived implementation.
+
+### Why is this bad?
+It is less concise.
+
+### Example
+```
+struct Foo {
+    bar: bool
+}
+
+impl Default for Foo {
+    fn default() -> Self {
+        Self {
+            bar: false
+        }
+    }
+}
+```
+
+Use instead:
+```
+#[derive(Default)]
+struct Foo {
+    bar: bool
+}
+```
+
+### Known problems
+Derive macros [sometimes use incorrect bounds](https://github.com/rust-lang/rust/issues/26925)
+in generic types and the user defined `impl` may be more generalized or
+specialized than what derive will produce. This lint can't detect the manual `impl`
+has exactly equal bounds, and therefore this lint is disabled for types with
+generic parameters.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/derive_hash_xor_eq.txt b/src/tools/clippy/src/docs/derive_hash_xor_eq.txt
new file mode 100644
index 000000000000..fbf623d5adbc
--- /dev/null
+++ b/src/tools/clippy/src/docs/derive_hash_xor_eq.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for deriving `Hash` but implementing `PartialEq`
+explicitly or vice versa.
+
+### Why is this bad?
+The implementation of these traits must agree (for
+example for use with `HashMap`) so it’s probably a bad idea to use a
+default-generated `Hash` implementation with an explicitly defined
+`PartialEq`. In particular, the following must hold for any type:
+
+```
+k1 == k2 ⇒ hash(k1) == hash(k2)
+```
+
+### Example
+```
+#[derive(Hash)]
+struct Foo;
+
+impl PartialEq for Foo {
+    ...
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/derive_ord_xor_partial_ord.txt b/src/tools/clippy/src/docs/derive_ord_xor_partial_ord.txt
new file mode 100644
index 000000000000..f2107a5f69ee
--- /dev/null
+++ b/src/tools/clippy/src/docs/derive_ord_xor_partial_ord.txt
@@ -0,0 +1,44 @@
+### What it does
+Checks for deriving `Ord` but implementing `PartialOrd`
+explicitly or vice versa.
+
+### Why is this bad?
+The implementation of these traits must agree (for
+example for use with `sort`) so it’s probably a bad idea to use a
+default-generated `Ord` implementation with an explicitly defined
+`PartialOrd`. In particular, the following must hold for any type
+implementing `Ord`:
+
+```
+k1.cmp(&k2) == k1.partial_cmp(&k2).unwrap()
+```
+
+### Example
+```
+#[derive(Ord, PartialEq, Eq)]
+struct Foo;
+
+impl PartialOrd for Foo {
+    ...
+}
+```
+Use instead:
+```
+#[derive(PartialEq, Eq)]
+struct Foo;
+
+impl PartialOrd for Foo {
+    fn partial_cmp(&self, other: &Foo) -> Option<Ordering> {
+       Some(self.cmp(other))
+    }
+}
+
+impl Ord for Foo {
+    ...
+}
+```
+or, if you don't need a custom ordering:
+```
+#[derive(Ord, PartialOrd, PartialEq, Eq)]
+struct Foo;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/derive_partial_eq_without_eq.txt b/src/tools/clippy/src/docs/derive_partial_eq_without_eq.txt
new file mode 100644
index 000000000000..932fabad666c
--- /dev/null
+++ b/src/tools/clippy/src/docs/derive_partial_eq_without_eq.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for types that derive `PartialEq` and could implement `Eq`.
+
+### Why is this bad?
+If a type `T` derives `PartialEq` and all of its members implement `Eq`,
+then `T` can always implement `Eq`. Implementing `Eq` allows `T` to be used
+in APIs that require `Eq` types. It also allows structs containing `T` to derive
+`Eq` themselves.
+
+### Example
+```
+#[derive(PartialEq)]
+struct Foo {
+    i_am_eq: i32,
+    i_am_eq_too: Vec<String>,
+}
+```
+Use instead:
+```
+#[derive(PartialEq, Eq)]
+struct Foo {
+    i_am_eq: i32,
+    i_am_eq_too: Vec<String>,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/disallowed_methods.txt b/src/tools/clippy/src/docs/disallowed_methods.txt
new file mode 100644
index 000000000000..d8ad5b6a6674
--- /dev/null
+++ b/src/tools/clippy/src/docs/disallowed_methods.txt
@@ -0,0 +1,41 @@
+### What it does
+Denies the configured methods and functions in clippy.toml
+
+Note: Even though this lint is warn-by-default, it will only trigger if
+methods are defined in the clippy.toml file.
+
+### Why is this bad?
+Some methods are undesirable in certain contexts, and it's beneficial to
+lint for them as needed.
+
+### Example
+An example clippy.toml configuration:
+```
+disallowed-methods = [
+    # Can use a string as the path of the disallowed method.
+    "std::boxed::Box::new",
+    # Can also use an inline table with a `path` key.
+    { path = "std::time::Instant::now" },
+    # When using an inline table, can add a `reason` for why the method
+    # is disallowed.
+    { path = "std::vec::Vec::leak", reason = "no leaking memory" },
+]
+```
+
+```
+// Example code where clippy issues a warning
+let xs = vec![1, 2, 3, 4];
+xs.leak(); // Vec::leak is disallowed in the config.
+// The diagnostic contains the message "no leaking memory".
+
+let _now = Instant::now(); // Instant::now is disallowed in the config.
+
+let _box = Box::new(3); // Box::new is disallowed in the config.
+```
+
+Use instead:
+```
+// Example code which does not raise clippy warning
+let mut xs = Vec::new(); // Vec::new is _not_ disallowed in the config.
+xs.push(123); // Vec::push is _not_ disallowed in the config.
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/disallowed_names.txt b/src/tools/clippy/src/docs/disallowed_names.txt
new file mode 100644
index 000000000000..f4aaee9c77b7
--- /dev/null
+++ b/src/tools/clippy/src/docs/disallowed_names.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for usage of disallowed names for variables, such
+as `foo`.
+
+### Why is this bad?
+These names are usually placeholder names and should be
+avoided.
+
+### Example
+```
+let foo = 3.14;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/disallowed_script_idents.txt b/src/tools/clippy/src/docs/disallowed_script_idents.txt
new file mode 100644
index 000000000000..2151b7a20ded
--- /dev/null
+++ b/src/tools/clippy/src/docs/disallowed_script_idents.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for usage of unicode scripts other than those explicitly allowed
+by the lint config.
+
+This lint doesn't take into account non-text scripts such as `Unknown` and `Linear_A`.
+It also ignores the `Common` script type.
+While configuring, be sure to use official script name [aliases] from
+[the list of supported scripts][supported_scripts].
+
+See also: [`non_ascii_idents`].
+
+[aliases]: http://www.unicode.org/reports/tr24/tr24-31.html#Script_Value_Aliases
+[supported_scripts]: https://www.unicode.org/iso15924/iso15924-codes.html
+
+### Why is this bad?
+It may be not desired to have many different scripts for
+identifiers in the codebase.
+
+Note that if you only want to allow plain English, you might want to use
+built-in [`non_ascii_idents`] lint instead.
+
+[`non_ascii_idents`]: https://doc.rust-lang.org/rustc/lints/listing/allowed-by-default.html#non-ascii-idents
+
+### Example
+```
+// Assuming that `clippy.toml` contains the following line:
+// allowed-locales = ["Latin", "Cyrillic"]
+let counter = 10; // OK, latin is allowed.
+let счётчик = 10; // OK, cyrillic is allowed.
+let zähler = 10; // OK, it's still latin.
+let カウンタ = 10; // Will spawn the lint.
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/disallowed_types.txt b/src/tools/clippy/src/docs/disallowed_types.txt
new file mode 100644
index 000000000000..2bcbcddee566
--- /dev/null
+++ b/src/tools/clippy/src/docs/disallowed_types.txt
@@ -0,0 +1,33 @@
+### What it does
+Denies the configured types in clippy.toml.
+
+Note: Even though this lint is warn-by-default, it will only trigger if
+types are defined in the clippy.toml file.
+
+### Why is this bad?
+Some types are undesirable in certain contexts.
+
+### Example:
+An example clippy.toml configuration:
+```
+disallowed-types = [
+    # Can use a string as the path of the disallowed type.
+    "std::collections::BTreeMap",
+    # Can also use an inline table with a `path` key.
+    { path = "std::net::TcpListener" },
+    # When using an inline table, can add a `reason` for why the type
+    # is disallowed.
+    { path = "std::net::Ipv4Addr", reason = "no IPv4 allowed" },
+]
+```
+
+```
+use std::collections::BTreeMap;
+// or its use
+let x = std::collections::BTreeMap::new();
+```
+Use instead:
+```
+// A similar type that is allowed by the config
+use std::collections::HashMap;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/diverging_sub_expression.txt b/src/tools/clippy/src/docs/diverging_sub_expression.txt
new file mode 100644
index 000000000000..194362218025
--- /dev/null
+++ b/src/tools/clippy/src/docs/diverging_sub_expression.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for diverging calls that are not match arms or
+statements.
+
+### Why is this bad?
+It is often confusing to read. In addition, the
+sub-expression evaluation order for Rust is not well documented.
+
+### Known problems
+Someone might want to use `some_bool || panic!()` as a
+shorthand.
+
+### Example
+```
+let a = b() || panic!() || c();
+// `c()` is dead, `panic!()` is only called if `b()` returns `false`
+let x = (a, b, c, panic!());
+// can simply be replaced by `panic!()`
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/doc_link_with_quotes.txt b/src/tools/clippy/src/docs/doc_link_with_quotes.txt
new file mode 100644
index 000000000000..107c8ac116d9
--- /dev/null
+++ b/src/tools/clippy/src/docs/doc_link_with_quotes.txt
@@ -0,0 +1,16 @@
+### What it does
+Detects the syntax `['foo']` in documentation comments (notice quotes instead of backticks)
+outside of code blocks
+### Why is this bad?
+It is likely a typo when defining an intra-doc link
+
+### Example
+```
+/// See also: ['foo']
+fn bar() {}
+```
+Use instead:
+```
+/// See also: [`foo`]
+fn bar() {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/doc_markdown.txt b/src/tools/clippy/src/docs/doc_markdown.txt
new file mode 100644
index 000000000000..94f54c587e30
--- /dev/null
+++ b/src/tools/clippy/src/docs/doc_markdown.txt
@@ -0,0 +1,35 @@
+### What it does
+Checks for the presence of `_`, `::` or camel-case words
+outside ticks in documentation.
+
+### Why is this bad?
+*Rustdoc* supports markdown formatting, `_`, `::` and
+camel-case probably indicates some code which should be included between
+ticks. `_` can also be used for emphasis in markdown, this lint tries to
+consider that.
+
+### Known problems
+Lots of bad docs won’t be fixed, what the lint checks
+for is limited, and there are still false positives. HTML elements and their
+content are not linted.
+
+In addition, when writing documentation comments, including `[]` brackets
+inside a link text would trip the parser. Therefore, documenting link with
+`[`SmallVec<[T; INLINE_CAPACITY]>`]` and then [`SmallVec<[T; INLINE_CAPACITY]>`]: SmallVec
+would fail.
+
+### Examples
+```
+/// Do something with the foo_bar parameter. See also
+/// that::other::module::foo.
+// ^ `foo_bar` and `that::other::module::foo` should be ticked.
+fn doit(foo_bar: usize) {}
+```
+
+```
+// Link text with `[]` brackets should be written as following:
+/// Consume the array and return the inner
+/// [`SmallVec<[T; INLINE_CAPACITY]>`][SmallVec].
+/// [SmallVec]: SmallVec
+fn main() {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/double_comparisons.txt b/src/tools/clippy/src/docs/double_comparisons.txt
new file mode 100644
index 000000000000..7dc6818779f4
--- /dev/null
+++ b/src/tools/clippy/src/docs/double_comparisons.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for double comparisons that could be simplified to a single expression.
+
+
+### Why is this bad?
+Readability.
+
+### Example
+```
+if x == y || x < y {}
+```
+
+Use instead:
+
+```
+if x <= y {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/double_must_use.txt b/src/tools/clippy/src/docs/double_must_use.txt
new file mode 100644
index 000000000000..0017d10d40d3
--- /dev/null
+++ b/src/tools/clippy/src/docs/double_must_use.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for a `#[must_use]` attribute without
+further information on functions and methods that return a type already
+marked as `#[must_use]`.
+
+### Why is this bad?
+The attribute isn't needed. Not using the result
+will already be reported. Alternatively, one can add some text to the
+attribute to improve the lint message.
+
+### Examples
+```
+#[must_use]
+fn double_must_use() -> Result<(), ()> {
+    unimplemented!();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/double_neg.txt b/src/tools/clippy/src/docs/double_neg.txt
new file mode 100644
index 000000000000..a07f67496d7c
--- /dev/null
+++ b/src/tools/clippy/src/docs/double_neg.txt
@@ -0,0 +1,12 @@
+### What it does
+Detects expressions of the form `--x`.
+
+### Why is this bad?
+It can mislead C/C++ programmers to think `x` was
+decremented.
+
+### Example
+```
+let mut x = 3;
+--x;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/double_parens.txt b/src/tools/clippy/src/docs/double_parens.txt
new file mode 100644
index 000000000000..260d7dd575e5
--- /dev/null
+++ b/src/tools/clippy/src/docs/double_parens.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for unnecessary double parentheses.
+
+### Why is this bad?
+This makes code harder to read and might indicate a
+mistake.
+
+### Example
+```
+fn simple_double_parens() -> i32 {
+    ((0))
+}
+
+foo((0));
+```
+
+Use instead:
+```
+fn simple_no_parens() -> i32 {
+    0
+}
+
+foo(0);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/drop_copy.txt b/src/tools/clippy/src/docs/drop_copy.txt
new file mode 100644
index 000000000000..f917ca8ed21a
--- /dev/null
+++ b/src/tools/clippy/src/docs/drop_copy.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for calls to `std::mem::drop` with a value
+that derives the Copy trait
+
+### Why is this bad?
+Calling `std::mem::drop` [does nothing for types that
+implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html), since the
+value will be copied and moved into the function on invocation.
+
+### Example
+```
+let x: i32 = 42; // i32 implements Copy
+std::mem::drop(x) // A copy of x is passed to the function, leaving the
+                  // original unaffected
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/drop_non_drop.txt b/src/tools/clippy/src/docs/drop_non_drop.txt
new file mode 100644
index 000000000000..ee1e3a6c216e
--- /dev/null
+++ b/src/tools/clippy/src/docs/drop_non_drop.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for calls to `std::mem::drop` with a value that does not implement `Drop`.
+
+### Why is this bad?
+Calling `std::mem::drop` is no different than dropping such a type. A different value may
+have been intended.
+
+### Example
+```
+struct Foo;
+let x = Foo;
+std::mem::drop(x);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/drop_ref.txt b/src/tools/clippy/src/docs/drop_ref.txt
new file mode 100644
index 000000000000..c4f7adf0cfa3
--- /dev/null
+++ b/src/tools/clippy/src/docs/drop_ref.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for calls to `std::mem::drop` with a reference
+instead of an owned value.
+
+### Why is this bad?
+Calling `drop` on a reference will only drop the
+reference itself, which is a no-op. It will not call the `drop` method (from
+the `Drop` trait implementation) on the underlying referenced value, which
+is likely what was intended.
+
+### Example
+```
+let mut lock_guard = mutex.lock();
+std::mem::drop(&lock_guard) // Should have been drop(lock_guard), mutex
+// still locked
+operation_that_requires_mutex_to_be_unlocked();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/duplicate_mod.txt b/src/tools/clippy/src/docs/duplicate_mod.txt
new file mode 100644
index 000000000000..709a9aba03ad
--- /dev/null
+++ b/src/tools/clippy/src/docs/duplicate_mod.txt
@@ -0,0 +1,31 @@
+### What it does
+Checks for files that are included as modules multiple times.
+
+### Why is this bad?
+Loading a file as a module more than once causes it to be compiled
+multiple times, taking longer and putting duplicate content into the
+module tree.
+
+### Example
+```
+// lib.rs
+mod a;
+mod b;
+```
+```
+// a.rs
+#[path = "./b.rs"]
+mod b;
+```
+
+Use instead:
+
+```
+// lib.rs
+mod a;
+mod b;
+```
+```
+// a.rs
+use crate::b;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/duplicate_underscore_argument.txt b/src/tools/clippy/src/docs/duplicate_underscore_argument.txt
new file mode 100644
index 000000000000..a8fcd6a9fbe6
--- /dev/null
+++ b/src/tools/clippy/src/docs/duplicate_underscore_argument.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for function arguments having the similar names
+differing by an underscore.
+
+### Why is this bad?
+It affects code readability.
+
+### Example
+```
+fn foo(a: i32, _a: i32) {}
+```
+
+Use instead:
+```
+fn bar(a: i32, _b: i32) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/duration_subsec.txt b/src/tools/clippy/src/docs/duration_subsec.txt
new file mode 100644
index 000000000000..e7e0ca88745e
--- /dev/null
+++ b/src/tools/clippy/src/docs/duration_subsec.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for calculation of subsecond microseconds or milliseconds
+from other `Duration` methods.
+
+### Why is this bad?
+It's more concise to call `Duration::subsec_micros()` or
+`Duration::subsec_millis()` than to calculate them.
+
+### Example
+```
+let micros = duration.subsec_nanos() / 1_000;
+let millis = duration.subsec_nanos() / 1_000_000;
+```
+
+Use instead:
+```
+let micros = duration.subsec_micros();
+let millis = duration.subsec_millis();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/else_if_without_else.txt b/src/tools/clippy/src/docs/else_if_without_else.txt
new file mode 100644
index 000000000000..33f5d0f91859
--- /dev/null
+++ b/src/tools/clippy/src/docs/else_if_without_else.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for usage of if expressions with an `else if` branch,
+but without a final `else` branch.
+
+### Why is this bad?
+Some coding guidelines require this (e.g., MISRA-C:2004 Rule 14.10).
+
+### Example
+```
+if x.is_positive() {
+    a();
+} else if x.is_negative() {
+    b();
+}
+```
+
+Use instead:
+
+```
+if x.is_positive() {
+    a();
+} else if x.is_negative() {
+    b();
+} else {
+    // We don't care about zero.
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/empty_drop.txt b/src/tools/clippy/src/docs/empty_drop.txt
new file mode 100644
index 000000000000..d0c0c24a9c88
--- /dev/null
+++ b/src/tools/clippy/src/docs/empty_drop.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for empty `Drop` implementations.
+
+### Why is this bad?
+Empty `Drop` implementations have no effect when dropping an instance of the type. They are
+most likely useless. However, an empty `Drop` implementation prevents a type from being
+destructured, which might be the intention behind adding the implementation as a marker.
+
+### Example
+```
+struct S;
+
+impl Drop for S {
+    fn drop(&mut self) {}
+}
+```
+Use instead:
+```
+struct S;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/empty_enum.txt b/src/tools/clippy/src/docs/empty_enum.txt
new file mode 100644
index 000000000000..f7b41c41ee5a
--- /dev/null
+++ b/src/tools/clippy/src/docs/empty_enum.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for `enum`s with no variants.
+
+As of this writing, the `never_type` is still a
+nightly-only experimental API. Therefore, this lint is only triggered
+if the `never_type` is enabled.
+
+### Why is this bad?
+If you want to introduce a type which
+can't be instantiated, you should use `!` (the primitive type "never"),
+or a wrapper around it, because `!` has more extensive
+compiler support (type inference, etc...) and wrappers
+around it are the conventional way to define an uninhabited type.
+For further information visit [never type documentation](https://doc.rust-lang.org/std/primitive.never.html)
+
+
+### Example
+```
+enum Test {}
+```
+
+Use instead:
+```
+#![feature(never_type)]
+
+struct Test(!);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/empty_line_after_outer_attr.txt b/src/tools/clippy/src/docs/empty_line_after_outer_attr.txt
new file mode 100644
index 000000000000..c85242bbee0e
--- /dev/null
+++ b/src/tools/clippy/src/docs/empty_line_after_outer_attr.txt
@@ -0,0 +1,35 @@
+### What it does
+Checks for empty lines after outer attributes
+
+### Why is this bad?
+Most likely the attribute was meant to be an inner attribute using a '!'.
+If it was meant to be an outer attribute, then the following item
+should not be separated by empty lines.
+
+### Known problems
+Can cause false positives.
+
+From the clippy side it's difficult to detect empty lines between an attributes and the
+following item because empty lines and comments are not part of the AST. The parsing
+currently works for basic cases but is not perfect.
+
+### Example
+```
+#[allow(dead_code)]
+
+fn not_quite_good_code() { }
+```
+
+Use instead:
+```
+// Good (as inner attribute)
+#![allow(dead_code)]
+
+fn this_is_fine() { }
+
+// or
+
+// Good (as outer attribute)
+#[allow(dead_code)]
+fn this_is_fine_too() { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/empty_loop.txt b/src/tools/clippy/src/docs/empty_loop.txt
new file mode 100644
index 000000000000..fea49a74d04e
--- /dev/null
+++ b/src/tools/clippy/src/docs/empty_loop.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for empty `loop` expressions.
+
+### Why is this bad?
+These busy loops burn CPU cycles without doing
+anything. It is _almost always_ a better idea to `panic!` than to have
+a busy loop.
+
+If panicking isn't possible, think of the environment and either:
+  - block on something
+  - sleep the thread for some microseconds
+  - yield or pause the thread
+
+For `std` targets, this can be done with
+[`std::thread::sleep`](https://doc.rust-lang.org/std/thread/fn.sleep.html)
+or [`std::thread::yield_now`](https://doc.rust-lang.org/std/thread/fn.yield_now.html).
+
+For `no_std` targets, doing this is more complicated, especially because
+`#[panic_handler]`s can't panic. To stop/pause the thread, you will
+probably need to invoke some target-specific intrinsic. Examples include:
+  - [`x86_64::instructions::hlt`](https://docs.rs/x86_64/0.12.2/x86_64/instructions/fn.hlt.html)
+  - [`cortex_m::asm::wfi`](https://docs.rs/cortex-m/0.6.3/cortex_m/asm/fn.wfi.html)
+
+### Example
+```
+loop {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/empty_structs_with_brackets.txt b/src/tools/clippy/src/docs/empty_structs_with_brackets.txt
new file mode 100644
index 000000000000..ab5e35ae2ada
--- /dev/null
+++ b/src/tools/clippy/src/docs/empty_structs_with_brackets.txt
@@ -0,0 +1,14 @@
+### What it does
+Finds structs without fields (a so-called "empty struct") that are declared with brackets.
+
+### Why is this bad?
+Empty brackets after a struct declaration can be omitted.
+
+### Example
+```
+struct Cookie {}
+```
+Use instead:
+```
+struct Cookie;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/enum_clike_unportable_variant.txt b/src/tools/clippy/src/docs/enum_clike_unportable_variant.txt
new file mode 100644
index 000000000000..d30a973a5a13
--- /dev/null
+++ b/src/tools/clippy/src/docs/enum_clike_unportable_variant.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for C-like enumerations that are
+`repr(isize/usize)` and have values that don't fit into an `i32`.
+
+### Why is this bad?
+This will truncate the variant value on 32 bit
+architectures, but works fine on 64 bit.
+
+### Example
+```
+#[repr(usize)]
+enum NonPortable {
+    X = 0x1_0000_0000,
+    Y = 0,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/enum_glob_use.txt b/src/tools/clippy/src/docs/enum_glob_use.txt
new file mode 100644
index 000000000000..3776822c35b0
--- /dev/null
+++ b/src/tools/clippy/src/docs/enum_glob_use.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for `use Enum::*`.
+
+### Why is this bad?
+It is usually better style to use the prefixed name of
+an enumeration variant, rather than importing variants.
+
+### Known problems
+Old-style enumerations that prefix the variants are
+still around.
+
+### Example
+```
+use std::cmp::Ordering::*;
+
+foo(Less);
+```
+
+Use instead:
+```
+use std::cmp::Ordering;
+
+foo(Ordering::Less)
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/enum_variant_names.txt b/src/tools/clippy/src/docs/enum_variant_names.txt
new file mode 100644
index 000000000000..e726925edda8
--- /dev/null
+++ b/src/tools/clippy/src/docs/enum_variant_names.txt
@@ -0,0 +1,30 @@
+### What it does
+Detects enumeration variants that are prefixed or suffixed
+by the same characters.
+
+### Why is this bad?
+Enumeration variant names should specify their variant,
+not repeat the enumeration name.
+
+### Limitations
+Characters with no casing will be considered when comparing prefixes/suffixes
+This applies to numbers and non-ascii characters without casing
+e.g. `Foo1` and `Foo2` is considered to have different prefixes
+(the prefixes are `Foo1` and `Foo2` respectively), as also `Bar螃`, `Bar蟹`
+
+### Example
+```
+enum Cake {
+    BlackForestCake,
+    HummingbirdCake,
+    BattenbergCake,
+}
+```
+Use instead:
+```
+enum Cake {
+    BlackForest,
+    Hummingbird,
+    Battenberg,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/eq_op.txt b/src/tools/clippy/src/docs/eq_op.txt
new file mode 100644
index 000000000000..2d75a0ec546e
--- /dev/null
+++ b/src/tools/clippy/src/docs/eq_op.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for equal operands to comparison, logical and
+bitwise, difference and division binary operators (`==`, `>`, etc., `&&`,
+`||`, `&`, `|`, `^`, `-` and `/`).
+
+### Why is this bad?
+This is usually just a typo or a copy and paste error.
+
+### Known problems
+False negatives: We had some false positives regarding
+calls (notably [racer](https://github.com/phildawes/racer) had one instance
+of `x.pop() && x.pop()`), so we removed matching any function or method
+calls. We may introduce a list of known pure functions in the future.
+
+### Example
+```
+if x + 1 == x + 1 {}
+
+// or
+
+assert_eq!(a, a);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/equatable_if_let.txt b/src/tools/clippy/src/docs/equatable_if_let.txt
new file mode 100644
index 000000000000..9997046954c2
--- /dev/null
+++ b/src/tools/clippy/src/docs/equatable_if_let.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for pattern matchings that can be expressed using equality.
+
+### Why is this bad?
+
+* It reads better and has less cognitive load because equality won't cause binding.
+* It is a [Yoda condition](https://en.wikipedia.org/wiki/Yoda_conditions). Yoda conditions are widely
+criticized for increasing the cognitive load of reading the code.
+* Equality is a simple bool expression and can be merged with `&&` and `||` and
+reuse if blocks
+
+### Example
+```
+if let Some(2) = x {
+    do_thing();
+}
+```
+Use instead:
+```
+if x == Some(2) {
+    do_thing();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/erasing_op.txt b/src/tools/clippy/src/docs/erasing_op.txt
new file mode 100644
index 000000000000..3d285a6d86e4
--- /dev/null
+++ b/src/tools/clippy/src/docs/erasing_op.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for erasing operations, e.g., `x * 0`.
+
+### Why is this bad?
+The whole expression can be replaced by zero.
+This is most likely not the intended outcome and should probably be
+corrected
+
+### Example
+```
+let x = 1;
+0 / x;
+0 * x;
+x & 0;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/err_expect.txt b/src/tools/clippy/src/docs/err_expect.txt
new file mode 100644
index 000000000000..1dc83c5ce0ee
--- /dev/null
+++ b/src/tools/clippy/src/docs/err_expect.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for `.err().expect()` calls on the `Result` type.
+
+### Why is this bad?
+`.expect_err()` can be called directly to avoid the extra type conversion from `err()`.
+
+### Example
+```
+let x: Result<u32, &str> = Ok(10);
+x.err().expect("Testing err().expect()");
+```
+Use instead:
+```
+let x: Result<u32, &str> = Ok(10);
+x.expect_err("Testing expect_err");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/excessive_precision.txt b/src/tools/clippy/src/docs/excessive_precision.txt
new file mode 100644
index 000000000000..517879c47152
--- /dev/null
+++ b/src/tools/clippy/src/docs/excessive_precision.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for float literals with a precision greater
+than that supported by the underlying type.
+
+### Why is this bad?
+Rust will truncate the literal silently.
+
+### Example
+```
+let v: f32 = 0.123_456_789_9;
+println!("{}", v); //  0.123_456_789
+```
+
+Use instead:
+```
+let v: f64 = 0.123_456_789_9;
+println!("{}", v); //  0.123_456_789_9
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/exhaustive_enums.txt b/src/tools/clippy/src/docs/exhaustive_enums.txt
new file mode 100644
index 000000000000..d1032a7a29aa
--- /dev/null
+++ b/src/tools/clippy/src/docs/exhaustive_enums.txt
@@ -0,0 +1,23 @@
+### What it does
+Warns on any exported `enum`s that are not tagged `#[non_exhaustive]`
+
+### Why is this bad?
+Exhaustive enums are typically fine, but a project which does
+not wish to make a stability commitment around exported enums may wish to
+disable them by default.
+
+### Example
+```
+enum Foo {
+    Bar,
+    Baz
+}
+```
+Use instead:
+```
+#[non_exhaustive]
+enum Foo {
+    Bar,
+    Baz
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/exhaustive_structs.txt b/src/tools/clippy/src/docs/exhaustive_structs.txt
new file mode 100644
index 000000000000..fd6e4f5caf1f
--- /dev/null
+++ b/src/tools/clippy/src/docs/exhaustive_structs.txt
@@ -0,0 +1,23 @@
+### What it does
+Warns on any exported `structs`s that are not tagged `#[non_exhaustive]`
+
+### Why is this bad?
+Exhaustive structs are typically fine, but a project which does
+not wish to make a stability commitment around exported structs may wish to
+disable them by default.
+
+### Example
+```
+struct Foo {
+    bar: u8,
+    baz: String,
+}
+```
+Use instead:
+```
+#[non_exhaustive]
+struct Foo {
+    bar: u8,
+    baz: String,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/exit.txt b/src/tools/clippy/src/docs/exit.txt
new file mode 100644
index 000000000000..1e6154d43e05
--- /dev/null
+++ b/src/tools/clippy/src/docs/exit.txt
@@ -0,0 +1,12 @@
+### What it does
+`exit()`  terminates the program and doesn't provide a
+stack trace.
+
+### Why is this bad?
+Ideally a program is terminated by finishing
+the main function.
+
+### Example
+```
+std::process::exit(0)
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/expect_fun_call.txt b/src/tools/clippy/src/docs/expect_fun_call.txt
new file mode 100644
index 000000000000..d82d9aa9baff
--- /dev/null
+++ b/src/tools/clippy/src/docs/expect_fun_call.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for calls to `.expect(&format!(...))`, `.expect(foo(..))`,
+etc., and suggests to use `unwrap_or_else` instead
+
+### Why is this bad?
+The function will always be called.
+
+### Known problems
+If the function has side-effects, not calling it will
+change the semantics of the program, but you shouldn't rely on that anyway.
+
+### Example
+```
+foo.expect(&format!("Err {}: {}", err_code, err_msg));
+
+// or
+
+foo.expect(format!("Err {}: {}", err_code, err_msg).as_str());
+```
+
+Use instead:
+```
+foo.unwrap_or_else(|| panic!("Err {}: {}", err_code, err_msg));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/expect_used.txt b/src/tools/clippy/src/docs/expect_used.txt
new file mode 100644
index 000000000000..4a6981e334fd
--- /dev/null
+++ b/src/tools/clippy/src/docs/expect_used.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for `.expect()` or `.expect_err()` calls on `Result`s and `.expect()` call on `Option`s.
+
+### Why is this bad?
+Usually it is better to handle the `None` or `Err` case.
+Still, for a lot of quick-and-dirty code, `expect` is a good choice, which is why
+this lint is `Allow` by default.
+
+`result.expect()` will let the thread panic on `Err`
+values. Normally, you want to implement more sophisticated error handling,
+and propagate errors upwards with `?` operator.
+
+### Examples
+```
+option.expect("one");
+result.expect("one");
+```
+
+Use instead:
+```
+option?;
+
+// or
+
+result?;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/expl_impl_clone_on_copy.txt b/src/tools/clippy/src/docs/expl_impl_clone_on_copy.txt
new file mode 100644
index 000000000000..391d93b6713c
--- /dev/null
+++ b/src/tools/clippy/src/docs/expl_impl_clone_on_copy.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for explicit `Clone` implementations for `Copy`
+types.
+
+### Why is this bad?
+To avoid surprising behavior, these traits should
+agree and the behavior of `Copy` cannot be overridden. In almost all
+situations a `Copy` type should have a `Clone` implementation that does
+nothing more than copy the object, which is what `#[derive(Copy, Clone)]`
+gets you.
+
+### Example
+```
+#[derive(Copy)]
+struct Foo;
+
+impl Clone for Foo {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/explicit_auto_deref.txt b/src/tools/clippy/src/docs/explicit_auto_deref.txt
new file mode 100644
index 000000000000..65b256317725
--- /dev/null
+++ b/src/tools/clippy/src/docs/explicit_auto_deref.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for dereferencing expressions which would be covered by auto-deref.
+
+### Why is this bad?
+This unnecessarily complicates the code.
+
+### Example
+```
+let x = String::new();
+let y: &str = &*x;
+```
+Use instead:
+```
+let x = String::new();
+let y: &str = &x;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/explicit_counter_loop.txt b/src/tools/clippy/src/docs/explicit_counter_loop.txt
new file mode 100644
index 000000000000..2661a43e1034
--- /dev/null
+++ b/src/tools/clippy/src/docs/explicit_counter_loop.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks `for` loops over slices with an explicit counter
+and suggests the use of `.enumerate()`.
+
+### Why is this bad?
+Using `.enumerate()` makes the intent more clear,
+declutters the code and may be faster in some instances.
+
+### Example
+```
+let mut i = 0;
+for item in &v {
+    bar(i, *item);
+    i += 1;
+}
+```
+
+Use instead:
+```
+for (i, item) in v.iter().enumerate() { bar(i, *item); }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/explicit_deref_methods.txt b/src/tools/clippy/src/docs/explicit_deref_methods.txt
new file mode 100644
index 000000000000..e14e981c7073
--- /dev/null
+++ b/src/tools/clippy/src/docs/explicit_deref_methods.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for explicit `deref()` or `deref_mut()` method calls.
+
+### Why is this bad?
+Dereferencing by `&*x` or `&mut *x` is clearer and more concise,
+when not part of a method chain.
+
+### Example
+```
+use std::ops::Deref;
+let a: &mut String = &mut String::from("foo");
+let b: &str = a.deref();
+```
+
+Use instead:
+```
+let a: &mut String = &mut String::from("foo");
+let b = &*a;
+```
+
+This lint excludes:
+```
+let _ = d.unwrap().deref();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/explicit_into_iter_loop.txt b/src/tools/clippy/src/docs/explicit_into_iter_loop.txt
new file mode 100644
index 000000000000..3931dfd69a31
--- /dev/null
+++ b/src/tools/clippy/src/docs/explicit_into_iter_loop.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for loops on `y.into_iter()` where `y` will do, and
+suggests the latter.
+
+### Why is this bad?
+Readability.
+
+### Example
+```
+// with `y` a `Vec` or slice:
+for x in y.into_iter() {
+    // ..
+}
+```
+can be rewritten to
+```
+for x in y {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/explicit_iter_loop.txt b/src/tools/clippy/src/docs/explicit_iter_loop.txt
new file mode 100644
index 000000000000..cabe72e91d04
--- /dev/null
+++ b/src/tools/clippy/src/docs/explicit_iter_loop.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for loops on `x.iter()` where `&x` will do, and
+suggests the latter.
+
+### Why is this bad?
+Readability.
+
+### Known problems
+False negatives. We currently only warn on some known
+types.
+
+### Example
+```
+// with `y` a `Vec` or slice:
+for x in y.iter() {
+    // ..
+}
+```
+
+Use instead:
+```
+for x in &y {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/explicit_write.txt b/src/tools/clippy/src/docs/explicit_write.txt
new file mode 100644
index 000000000000..eafed5d39e5c
--- /dev/null
+++ b/src/tools/clippy/src/docs/explicit_write.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for usage of `write!()` / `writeln()!` which can be
+replaced with `(e)print!()` / `(e)println!()`
+
+### Why is this bad?
+Using `(e)println! is clearer and more concise
+
+### Example
+```
+writeln!(&mut std::io::stderr(), "foo: {:?}", bar).unwrap();
+writeln!(&mut std::io::stdout(), "foo: {:?}", bar).unwrap();
+```
+
+Use instead:
+```
+eprintln!("foo: {:?}", bar);
+println!("foo: {:?}", bar);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/extend_with_drain.txt b/src/tools/clippy/src/docs/extend_with_drain.txt
new file mode 100644
index 000000000000..2f31dcf5f740
--- /dev/null
+++ b/src/tools/clippy/src/docs/extend_with_drain.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for occurrences where one vector gets extended instead of append
+
+### Why is this bad?
+Using `append` instead of `extend` is more concise and faster
+
+### Example
+```
+let mut a = vec![1, 2, 3];
+let mut b = vec![4, 5, 6];
+
+a.extend(b.drain(..));
+```
+
+Use instead:
+```
+let mut a = vec![1, 2, 3];
+let mut b = vec![4, 5, 6];
+
+a.append(&mut b);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/extra_unused_lifetimes.txt b/src/tools/clippy/src/docs/extra_unused_lifetimes.txt
new file mode 100644
index 000000000000..bc1814aa4752
--- /dev/null
+++ b/src/tools/clippy/src/docs/extra_unused_lifetimes.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for lifetimes in generics that are never used
+anywhere else.
+
+### Why is this bad?
+The additional lifetimes make the code look more
+complicated, while there is nothing out of the ordinary going on. Removing
+them leads to more readable code.
+
+### Example
+```
+// unnecessary lifetimes
+fn unused_lifetime<'a>(x: u8) {
+    // ..
+}
+```
+
+Use instead:
+```
+fn no_lifetime(x: u8) {
+    // ...
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/fallible_impl_from.txt b/src/tools/clippy/src/docs/fallible_impl_from.txt
new file mode 100644
index 000000000000..588a5bb103d4
--- /dev/null
+++ b/src/tools/clippy/src/docs/fallible_impl_from.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for impls of `From<..>` that contain `panic!()` or `unwrap()`
+
+### Why is this bad?
+`TryFrom` should be used if there's a possibility of failure.
+
+### Example
+```
+struct Foo(i32);
+
+impl From<String> for Foo {
+    fn from(s: String) -> Self {
+        Foo(s.parse().unwrap())
+    }
+}
+```
+
+Use instead:
+```
+struct Foo(i32);
+
+impl TryFrom<String> for Foo {
+    type Error = ();
+    fn try_from(s: String) -> Result<Self, Self::Error> {
+        if let Ok(parsed) = s.parse() {
+            Ok(Foo(parsed))
+        } else {
+            Err(())
+        }
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/field_reassign_with_default.txt b/src/tools/clippy/src/docs/field_reassign_with_default.txt
new file mode 100644
index 000000000000..e58b7239fde9
--- /dev/null
+++ b/src/tools/clippy/src/docs/field_reassign_with_default.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for immediate reassignment of fields initialized
+with Default::default().
+
+### Why is this bad?
+It's more idiomatic to use the [functional update syntax](https://doc.rust-lang.org/reference/expressions/struct-expr.html#functional-update-syntax).
+
+### Known problems
+Assignments to patterns that are of tuple type are not linted.
+
+### Example
+```
+let mut a: A = Default::default();
+a.i = 42;
+```
+
+Use instead:
+```
+let a = A {
+    i: 42,
+    .. Default::default()
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/filetype_is_file.txt b/src/tools/clippy/src/docs/filetype_is_file.txt
new file mode 100644
index 000000000000..ad14bd62c4de
--- /dev/null
+++ b/src/tools/clippy/src/docs/filetype_is_file.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for `FileType::is_file()`.
+
+### Why is this bad?
+When people testing a file type with `FileType::is_file`
+they are testing whether a path is something they can get bytes from. But
+`is_file` doesn't cover special file types in unix-like systems, and doesn't cover
+symlink in windows. Using `!FileType::is_dir()` is a better way to that intention.
+
+### Example
+```
+let metadata = std::fs::metadata("foo.txt")?;
+let filetype = metadata.file_type();
+
+if filetype.is_file() {
+    // read file
+}
+```
+
+should be written as:
+
+```
+let metadata = std::fs::metadata("foo.txt")?;
+let filetype = metadata.file_type();
+
+if !filetype.is_dir() {
+    // read file
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/filter_map_identity.txt b/src/tools/clippy/src/docs/filter_map_identity.txt
new file mode 100644
index 000000000000..83b666f2e278
--- /dev/null
+++ b/src/tools/clippy/src/docs/filter_map_identity.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for usage of `filter_map(|x| x)`.
+
+### Why is this bad?
+Readability, this can be written more concisely by using `flatten`.
+
+### Example
+```
+iter.filter_map(|x| x);
+```
+Use instead:
+```
+iter.flatten();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/filter_map_next.txt b/src/tools/clippy/src/docs/filter_map_next.txt
new file mode 100644
index 000000000000..b38620b56a50
--- /dev/null
+++ b/src/tools/clippy/src/docs/filter_map_next.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of `_.filter_map(_).next()`.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.find_map(_)`.
+
+### Example
+```
+ (0..3).filter_map(|x| if x == 2 { Some(x) } else { None }).next();
+```
+Can be written as
+
+```
+ (0..3).find_map(|x| if x == 2 { Some(x) } else { None });
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/filter_next.txt b/src/tools/clippy/src/docs/filter_next.txt
new file mode 100644
index 000000000000..898a74166dc1
--- /dev/null
+++ b/src/tools/clippy/src/docs/filter_next.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of `_.filter(_).next()`.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.find(_)`.
+
+### Example
+```
+vec.iter().filter(|x| **x == 0).next();
+```
+
+Use instead:
+```
+vec.iter().find(|x| **x == 0);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/flat_map_identity.txt b/src/tools/clippy/src/docs/flat_map_identity.txt
new file mode 100644
index 000000000000..a5ee79b4982f
--- /dev/null
+++ b/src/tools/clippy/src/docs/flat_map_identity.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for usage of `flat_map(|x| x)`.
+
+### Why is this bad?
+Readability, this can be written more concisely by using `flatten`.
+
+### Example
+```
+iter.flat_map(|x| x);
+```
+Can be written as
+```
+iter.flatten();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/flat_map_option.txt b/src/tools/clippy/src/docs/flat_map_option.txt
new file mode 100644
index 000000000000..d50b9156d365
--- /dev/null
+++ b/src/tools/clippy/src/docs/flat_map_option.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usages of `Iterator::flat_map()` where `filter_map()` could be
+used instead.
+
+### Why is this bad?
+When applicable, `filter_map()` is more clear since it shows that
+`Option` is used to produce 0 or 1 items.
+
+### Example
+```
+let nums: Vec<i32> = ["1", "2", "whee!"].iter().flat_map(|x| x.parse().ok()).collect();
+```
+Use instead:
+```
+let nums: Vec<i32> = ["1", "2", "whee!"].iter().filter_map(|x| x.parse().ok()).collect();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/float_arithmetic.txt b/src/tools/clippy/src/docs/float_arithmetic.txt
new file mode 100644
index 000000000000..1f9bce5abd59
--- /dev/null
+++ b/src/tools/clippy/src/docs/float_arithmetic.txt
@@ -0,0 +1,11 @@
+### What it does
+Checks for float arithmetic.
+
+### Why is this bad?
+For some embedded systems or kernel development, it
+can be useful to rule out floating-point numbers.
+
+### Example
+```
+a + 1.0;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/float_cmp.txt b/src/tools/clippy/src/docs/float_cmp.txt
new file mode 100644
index 000000000000..c19907c903e9
--- /dev/null
+++ b/src/tools/clippy/src/docs/float_cmp.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for (in-)equality comparisons on floating-point
+values (apart from zero), except in functions called `*eq*` (which probably
+implement equality for a type involving floats).
+
+### Why is this bad?
+Floating point calculations are usually imprecise, so
+asking if two values are *exactly* equal is asking for trouble. For a good
+guide on what to do, see [the floating point
+guide](http://www.floating-point-gui.de/errors/comparison).
+
+### Example
+```
+let x = 1.2331f64;
+let y = 1.2332f64;
+
+if y == 1.23f64 { }
+if y != x {} // where both are floats
+```
+
+Use instead:
+```
+let error_margin = f64::EPSILON; // Use an epsilon for comparison
+// Or, if Rust <= 1.42, use `std::f64::EPSILON` constant instead.
+// let error_margin = std::f64::EPSILON;
+if (y - 1.23f64).abs() < error_margin { }
+if (y - x).abs() > error_margin { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/float_cmp_const.txt b/src/tools/clippy/src/docs/float_cmp_const.txt
new file mode 100644
index 000000000000..9208feaacd81
--- /dev/null
+++ b/src/tools/clippy/src/docs/float_cmp_const.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for (in-)equality comparisons on floating-point
+value and constant, except in functions called `*eq*` (which probably
+implement equality for a type involving floats).
+
+### Why is this bad?
+Floating point calculations are usually imprecise, so
+asking if two values are *exactly* equal is asking for trouble. For a good
+guide on what to do, see [the floating point
+guide](http://www.floating-point-gui.de/errors/comparison).
+
+### Example
+```
+let x: f64 = 1.0;
+const ONE: f64 = 1.00;
+
+if x == ONE { } // where both are floats
+```
+
+Use instead:
+```
+let error_margin = f64::EPSILON; // Use an epsilon for comparison
+// Or, if Rust <= 1.42, use `std::f64::EPSILON` constant instead.
+// let error_margin = std::f64::EPSILON;
+if (x - ONE).abs() < error_margin { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/float_equality_without_abs.txt b/src/tools/clippy/src/docs/float_equality_without_abs.txt
new file mode 100644
index 000000000000..556b574e15d3
--- /dev/null
+++ b/src/tools/clippy/src/docs/float_equality_without_abs.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for statements of the form `(a - b) < f32::EPSILON` or
+`(a - b) < f64::EPSILON`. Notes the missing `.abs()`.
+
+### Why is this bad?
+The code without `.abs()` is more likely to have a bug.
+
+### Known problems
+If the user can ensure that b is larger than a, the `.abs()` is
+technically unnecessary. However, it will make the code more robust and doesn't have any
+large performance implications. If the abs call was deliberately left out for performance
+reasons, it is probably better to state this explicitly in the code, which then can be done
+with an allow.
+
+### Example
+```
+pub fn is_roughly_equal(a: f32, b: f32) -> bool {
+    (a - b) < f32::EPSILON
+}
+```
+Use instead:
+```
+pub fn is_roughly_equal(a: f32, b: f32) -> bool {
+    (a - b).abs() < f32::EPSILON
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/fn_address_comparisons.txt b/src/tools/clippy/src/docs/fn_address_comparisons.txt
new file mode 100644
index 000000000000..7d2b7b681deb
--- /dev/null
+++ b/src/tools/clippy/src/docs/fn_address_comparisons.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for comparisons with an address of a function item.
+
+### Why is this bad?
+Function item address is not guaranteed to be unique and could vary
+between different code generation units. Furthermore different function items could have
+the same address after being merged together.
+
+### Example
+```
+type F = fn();
+fn a() {}
+let f: F = a;
+if f == a {
+    // ...
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/fn_params_excessive_bools.txt b/src/tools/clippy/src/docs/fn_params_excessive_bools.txt
new file mode 100644
index 000000000000..2eae0563368c
--- /dev/null
+++ b/src/tools/clippy/src/docs/fn_params_excessive_bools.txt
@@ -0,0 +1,31 @@
+### What it does
+Checks for excessive use of
+bools in function definitions.
+
+### Why is this bad?
+Calls to such functions
+are confusing and error prone, because it's
+hard to remember argument order and you have
+no type system support to back you up. Using
+two-variant enums instead of bools often makes
+API easier to use.
+
+### Example
+```
+fn f(is_round: bool, is_hot: bool) { ... }
+```
+
+Use instead:
+```
+enum Shape {
+    Round,
+    Spiky,
+}
+
+enum Temperature {
+    Hot,
+    IceCold,
+}
+
+fn f(shape: Shape, temperature: Temperature) { ... }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/fn_to_numeric_cast.txt b/src/tools/clippy/src/docs/fn_to_numeric_cast.txt
new file mode 100644
index 000000000000..1f587f6d7176
--- /dev/null
+++ b/src/tools/clippy/src/docs/fn_to_numeric_cast.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for casts of function pointers to something other than usize
+
+### Why is this bad?
+Casting a function pointer to anything other than usize/isize is not portable across
+architectures, because you end up losing bits if the target type is too small or end up with a
+bunch of extra bits that waste space and add more instructions to the final binary than
+strictly necessary for the problem
+
+Casting to isize also doesn't make sense since there are no signed addresses.
+
+### Example
+```
+fn fun() -> i32 { 1 }
+let _ = fun as i64;
+```
+
+Use instead:
+```
+let _ = fun as usize;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/fn_to_numeric_cast_any.txt b/src/tools/clippy/src/docs/fn_to_numeric_cast_any.txt
new file mode 100644
index 000000000000..ee3c33d23725
--- /dev/null
+++ b/src/tools/clippy/src/docs/fn_to_numeric_cast_any.txt
@@ -0,0 +1,35 @@
+### What it does
+Checks for casts of a function pointer to any integer type.
+
+### Why is this bad?
+Casting a function pointer to an integer can have surprising results and can occur
+accidentally if parentheses are omitted from a function call. If you aren't doing anything
+low-level with function pointers then you can opt-out of casting functions to integers in
+order to avoid mistakes. Alternatively, you can use this lint to audit all uses of function
+pointer casts in your code.
+
+### Example
+```
+// fn1 is cast as `usize`
+fn fn1() -> u16 {
+    1
+};
+let _ = fn1 as usize;
+```
+
+Use instead:
+```
+// maybe you intended to call the function?
+fn fn2() -> u16 {
+    1
+};
+let _ = fn2() as usize;
+
+// or
+
+// maybe you intended to cast it to a function type?
+fn fn3() -> u16 {
+    1
+}
+let _ = fn3 as fn() -> u16;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/fn_to_numeric_cast_with_truncation.txt b/src/tools/clippy/src/docs/fn_to_numeric_cast_with_truncation.txt
new file mode 100644
index 000000000000..69f12fa319f1
--- /dev/null
+++ b/src/tools/clippy/src/docs/fn_to_numeric_cast_with_truncation.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for casts of a function pointer to a numeric type not wide enough to
+store address.
+
+### Why is this bad?
+Such a cast discards some bits of the function's address. If this is intended, it would be more
+clearly expressed by casting to usize first, then casting the usize to the intended type (with
+a comment) to perform the truncation.
+
+### Example
+```
+fn fn1() -> i16 {
+    1
+};
+let _ = fn1 as i32;
+```
+
+Use instead:
+```
+// Cast to usize first, then comment with the reason for the truncation
+fn fn1() -> i16 {
+    1
+};
+let fn_ptr = fn1 as usize;
+let fn_ptr_truncated = fn_ptr as i32;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/for_kv_map.txt b/src/tools/clippy/src/docs/for_kv_map.txt
new file mode 100644
index 000000000000..a9a2ffee9c74
--- /dev/null
+++ b/src/tools/clippy/src/docs/for_kv_map.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for iterating a map (`HashMap` or `BTreeMap`) and
+ignoring either the keys or values.
+
+### Why is this bad?
+Readability. There are `keys` and `values` methods that
+can be used to express that don't need the values or keys.
+
+### Example
+```
+for (k, _) in &map {
+    ..
+}
+```
+
+could be replaced by
+
+```
+for k in map.keys() {
+    ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/for_loops_over_fallibles.txt b/src/tools/clippy/src/docs/for_loops_over_fallibles.txt
new file mode 100644
index 000000000000..c5a7508e45d4
--- /dev/null
+++ b/src/tools/clippy/src/docs/for_loops_over_fallibles.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for `for` loops over `Option` or `Result` values.
+
+### Why is this bad?
+Readability. This is more clearly expressed as an `if
+let`.
+
+### Example
+```
+for x in opt {
+    // ..
+}
+
+for x in &res {
+    // ..
+}
+
+for x in res.iter() {
+    // ..
+}
+```
+
+Use instead:
+```
+if let Some(x) = opt {
+    // ..
+}
+
+if let Ok(x) = res {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/forget_copy.txt b/src/tools/clippy/src/docs/forget_copy.txt
new file mode 100644
index 000000000000..1d100912e9a4
--- /dev/null
+++ b/src/tools/clippy/src/docs/forget_copy.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for calls to `std::mem::forget` with a value that
+derives the Copy trait
+
+### Why is this bad?
+Calling `std::mem::forget` [does nothing for types that
+implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html) since the
+value will be copied and moved into the function on invocation.
+
+An alternative, but also valid, explanation is that Copy types do not
+implement
+the Drop trait, which means they have no destructors. Without a destructor,
+there
+is nothing for `std::mem::forget` to ignore.
+
+### Example
+```
+let x: i32 = 42; // i32 implements Copy
+std::mem::forget(x) // A copy of x is passed to the function, leaving the
+                    // original unaffected
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/forget_non_drop.txt b/src/tools/clippy/src/docs/forget_non_drop.txt
new file mode 100644
index 000000000000..3307d654c17f
--- /dev/null
+++ b/src/tools/clippy/src/docs/forget_non_drop.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for calls to `std::mem::forget` with a value that does not implement `Drop`.
+
+### Why is this bad?
+Calling `std::mem::forget` is no different than dropping such a type. A different value may
+have been intended.
+
+### Example
+```
+struct Foo;
+let x = Foo;
+std::mem::forget(x);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/forget_ref.txt b/src/tools/clippy/src/docs/forget_ref.txt
new file mode 100644
index 000000000000..874fb8786068
--- /dev/null
+++ b/src/tools/clippy/src/docs/forget_ref.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for calls to `std::mem::forget` with a reference
+instead of an owned value.
+
+### Why is this bad?
+Calling `forget` on a reference will only forget the
+reference itself, which is a no-op. It will not forget the underlying
+referenced
+value, which is likely what was intended.
+
+### Example
+```
+let x = Box::new(1);
+std::mem::forget(&x) // Should have been forget(x), x will still be dropped
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/format_in_format_args.txt b/src/tools/clippy/src/docs/format_in_format_args.txt
new file mode 100644
index 000000000000..ac498472f017
--- /dev/null
+++ b/src/tools/clippy/src/docs/format_in_format_args.txt
@@ -0,0 +1,16 @@
+### What it does
+Detects `format!` within the arguments of another macro that does
+formatting such as `format!` itself, `write!` or `println!`. Suggests
+inlining the `format!` call.
+
+### Why is this bad?
+The recommended code is both shorter and avoids a temporary allocation.
+
+### Example
+```
+println!("error: {}", format!("something failed at {}", Location::caller()));
+```
+Use instead:
+```
+println!("error: something failed at {}", Location::caller());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/format_push_string.txt b/src/tools/clippy/src/docs/format_push_string.txt
new file mode 100644
index 000000000000..ca409ebc7ec2
--- /dev/null
+++ b/src/tools/clippy/src/docs/format_push_string.txt
@@ -0,0 +1,26 @@
+### What it does
+Detects cases where the result of a `format!` call is
+appended to an existing `String`.
+
+### Why is this bad?
+Introduces an extra, avoidable heap allocation.
+
+### Known problems
+`format!` returns a `String` but `write!` returns a `Result`.
+Thus you are forced to ignore the `Err` variant to achieve the same API.
+
+While using `write!` in the suggested way should never fail, this isn't necessarily clear to the programmer.
+
+### Example
+```
+let mut s = String::new();
+s += &format!("0x{:X}", 1024);
+s.push_str(&format!("0x{:X}", 1024));
+```
+Use instead:
+```
+use std::fmt::Write as _; // import without risk of name clashing
+
+let mut s = String::new();
+let _ = write!(s, "0x{:X}", 1024);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/from_iter_instead_of_collect.txt b/src/tools/clippy/src/docs/from_iter_instead_of_collect.txt
new file mode 100644
index 000000000000..f3fd27597264
--- /dev/null
+++ b/src/tools/clippy/src/docs/from_iter_instead_of_collect.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for `from_iter()` function calls on types that implement the `FromIterator`
+trait.
+
+### Why is this bad?
+It is recommended style to use collect. See
+[FromIterator documentation](https://doc.rust-lang.org/std/iter/trait.FromIterator.html)
+
+### Example
+```
+let five_fives = std::iter::repeat(5).take(5);
+
+let v = Vec::from_iter(five_fives);
+
+assert_eq!(v, vec![5, 5, 5, 5, 5]);
+```
+Use instead:
+```
+let five_fives = std::iter::repeat(5).take(5);
+
+let v: Vec<i32> = five_fives.collect();
+
+assert_eq!(v, vec![5, 5, 5, 5, 5]);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/from_over_into.txt b/src/tools/clippy/src/docs/from_over_into.txt
new file mode 100644
index 000000000000..0770bcc42c27
--- /dev/null
+++ b/src/tools/clippy/src/docs/from_over_into.txt
@@ -0,0 +1,26 @@
+### What it does
+Searches for implementations of the `Into<..>` trait and suggests to implement `From<..>` instead.
+
+### Why is this bad?
+According the std docs implementing `From<..>` is preferred since it gives you `Into<..>` for free where the reverse isn't true.
+
+### Example
+```
+struct StringWrapper(String);
+
+impl Into<StringWrapper> for String {
+    fn into(self) -> StringWrapper {
+        StringWrapper(self)
+    }
+}
+```
+Use instead:
+```
+struct StringWrapper(String);
+
+impl From<String> for StringWrapper {
+    fn from(s: String) -> StringWrapper {
+        StringWrapper(s)
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/from_str_radix_10.txt b/src/tools/clippy/src/docs/from_str_radix_10.txt
new file mode 100644
index 000000000000..f6f319d3eaa1
--- /dev/null
+++ b/src/tools/clippy/src/docs/from_str_radix_10.txt
@@ -0,0 +1,25 @@
+### What it does
+
+Checks for function invocations of the form `primitive::from_str_radix(s, 10)`
+
+### Why is this bad?
+
+This specific common use case can be rewritten as `s.parse::<primitive>()`
+(and in most cases, the turbofish can be removed), which reduces code length
+and complexity.
+
+### Known problems
+
+This lint may suggest using (&<expression>).parse() instead of <expression>.parse() directly
+in some cases, which is correct but adds unnecessary complexity to the code.
+
+### Example
+```
+let input: &str = get_input();
+let num = u16::from_str_radix(input, 10)?;
+```
+Use instead:
+```
+let input: &str = get_input();
+let num: u16 = input.parse()?;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/future_not_send.txt b/src/tools/clippy/src/docs/future_not_send.txt
new file mode 100644
index 000000000000..0aa048d27355
--- /dev/null
+++ b/src/tools/clippy/src/docs/future_not_send.txt
@@ -0,0 +1,29 @@
+### What it does
+This lint requires Future implementations returned from
+functions and methods to implement the `Send` marker trait. It is mostly
+used by library authors (public and internal) that target an audience where
+multithreaded executors are likely to be used for running these Futures.
+
+### Why is this bad?
+A Future implementation captures some state that it
+needs to eventually produce its final value. When targeting a multithreaded
+executor (which is the norm on non-embedded devices) this means that this
+state may need to be transported to other threads, in other words the
+whole Future needs to implement the `Send` marker trait. If it does not,
+then the resulting Future cannot be submitted to a thread pool in the
+end user’s code.
+
+Especially for generic functions it can be confusing to leave the
+discovery of this problem to the end user: the reported error location
+will be far from its cause and can in many cases not even be fixed without
+modifying the library where the offending Future implementation is
+produced.
+
+### Example
+```
+async fn not_send(bytes: std::rc::Rc<[u8]>) {}
+```
+Use instead:
+```
+async fn is_send(bytes: std::sync::Arc<[u8]>) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/get_first.txt b/src/tools/clippy/src/docs/get_first.txt
new file mode 100644
index 000000000000..c905a737ddf3
--- /dev/null
+++ b/src/tools/clippy/src/docs/get_first.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for using `x.get(0)` instead of
+`x.first()`.
+
+### Why is this bad?
+Using `x.first()` is easier to read and has the same
+result.
+
+### Example
+```
+let x = vec![2, 3, 5];
+let first_element = x.get(0);
+```
+
+Use instead:
+```
+let x = vec![2, 3, 5];
+let first_element = x.first();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/get_last_with_len.txt b/src/tools/clippy/src/docs/get_last_with_len.txt
new file mode 100644
index 000000000000..31c7f269586a
--- /dev/null
+++ b/src/tools/clippy/src/docs/get_last_with_len.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for using `x.get(x.len() - 1)` instead of
+`x.last()`.
+
+### Why is this bad?
+Using `x.last()` is easier to read and has the same
+result.
+
+Note that using `x[x.len() - 1]` is semantically different from
+`x.last()`.  Indexing into the array will panic on out-of-bounds
+accesses, while `x.get()` and `x.last()` will return `None`.
+
+There is another lint (get_unwrap) that covers the case of using
+`x.get(index).unwrap()` instead of `x[index]`.
+
+### Example
+```
+let x = vec![2, 3, 5];
+let last_element = x.get(x.len() - 1);
+```
+
+Use instead:
+```
+let x = vec![2, 3, 5];
+let last_element = x.last();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/get_unwrap.txt b/src/tools/clippy/src/docs/get_unwrap.txt
new file mode 100644
index 000000000000..8defc2224416
--- /dev/null
+++ b/src/tools/clippy/src/docs/get_unwrap.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for use of `.get().unwrap()` (or
+`.get_mut().unwrap`) on a standard library type which implements `Index`
+
+### Why is this bad?
+Using the Index trait (`[]`) is more clear and more
+concise.
+
+### Known problems
+Not a replacement for error handling: Using either
+`.unwrap()` or the Index trait (`[]`) carries the risk of causing a `panic`
+if the value being accessed is `None`. If the use of `.get().unwrap()` is a
+temporary placeholder for dealing with the `Option` type, then this does
+not mitigate the need for error handling. If there is a chance that `.get()`
+will be `None` in your program, then it is advisable that the `None` case
+is handled in a future refactor instead of using `.unwrap()` or the Index
+trait.
+
+### Example
+```
+let mut some_vec = vec![0, 1, 2, 3];
+let last = some_vec.get(3).unwrap();
+*some_vec.get_mut(0).unwrap() = 1;
+```
+The correct use would be:
+```
+let mut some_vec = vec![0, 1, 2, 3];
+let last = some_vec[3];
+some_vec[0] = 1;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/identity_op.txt b/src/tools/clippy/src/docs/identity_op.txt
new file mode 100644
index 000000000000..a8e40bb43e9d
--- /dev/null
+++ b/src/tools/clippy/src/docs/identity_op.txt
@@ -0,0 +1,11 @@
+### What it does
+Checks for identity operations, e.g., `x + 0`.
+
+### Why is this bad?
+This code can be removed without changing the
+meaning. So it just obscures what's going on. Delete it mercilessly.
+
+### Example
+```
+x / 1 + 0 * 1 - 0 | 0;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/if_let_mutex.txt b/src/tools/clippy/src/docs/if_let_mutex.txt
new file mode 100644
index 000000000000..4d873ade9ace
--- /dev/null
+++ b/src/tools/clippy/src/docs/if_let_mutex.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for `Mutex::lock` calls in `if let` expression
+with lock calls in any of the else blocks.
+
+### Why is this bad?
+The Mutex lock remains held for the whole
+`if let ... else` block and deadlocks.
+
+### Example
+```
+if let Ok(thing) = mutex.lock() {
+    do_thing();
+} else {
+    mutex.lock();
+}
+```
+Should be written
+```
+let locked = mutex.lock();
+if let Ok(thing) = locked {
+    do_thing(thing);
+} else {
+    use_locked(locked);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/if_not_else.txt b/src/tools/clippy/src/docs/if_not_else.txt
new file mode 100644
index 000000000000..0e5ac4ce6bb8
--- /dev/null
+++ b/src/tools/clippy/src/docs/if_not_else.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for usage of `!` or `!=` in an if condition with an
+else branch.
+
+### Why is this bad?
+Negations reduce the readability of statements.
+
+### Example
+```
+if !v.is_empty() {
+    a()
+} else {
+    b()
+}
+```
+
+Could be written:
+
+```
+if v.is_empty() {
+    b()
+} else {
+    a()
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/if_same_then_else.txt b/src/tools/clippy/src/docs/if_same_then_else.txt
new file mode 100644
index 000000000000..75127016bb8c
--- /dev/null
+++ b/src/tools/clippy/src/docs/if_same_then_else.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for `if/else` with the same body as the *then* part
+and the *else* part.
+
+### Why is this bad?
+This is probably a copy & paste error.
+
+### Example
+```
+let foo = if … {
+    42
+} else {
+    42
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/if_then_some_else_none.txt b/src/tools/clippy/src/docs/if_then_some_else_none.txt
new file mode 100644
index 000000000000..13744f920e36
--- /dev/null
+++ b/src/tools/clippy/src/docs/if_then_some_else_none.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for if-else that could be written using either `bool::then` or `bool::then_some`.
+
+### Why is this bad?
+Looks a little redundant. Using `bool::then` is more concise and incurs no loss of clarity.
+For simple calculations and known values, use `bool::then_some`, which is eagerly evaluated
+in comparison to `bool::then`.
+
+### Example
+```
+let a = if v.is_empty() {
+    println!("true!");
+    Some(42)
+} else {
+    None
+};
+```
+
+Could be written:
+
+```
+let a = v.is_empty().then(|| {
+    println!("true!");
+    42
+});
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ifs_same_cond.txt b/src/tools/clippy/src/docs/ifs_same_cond.txt
new file mode 100644
index 000000000000..024ba5df93a6
--- /dev/null
+++ b/src/tools/clippy/src/docs/ifs_same_cond.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for consecutive `if`s with the same condition.
+
+### Why is this bad?
+This is probably a copy & paste error.
+
+### Example
+```
+if a == b {
+    …
+} else if a == b {
+    …
+}
+```
+
+Note that this lint ignores all conditions with a function call as it could
+have side effects:
+
+```
+if foo() {
+    …
+} else if foo() { // not linted
+    …
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/implicit_clone.txt b/src/tools/clippy/src/docs/implicit_clone.txt
new file mode 100644
index 000000000000..f5aa112c52c3
--- /dev/null
+++ b/src/tools/clippy/src/docs/implicit_clone.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for the usage of `_.to_owned()`, `vec.to_vec()`, or similar when calling `_.clone()` would be clearer.
+
+### Why is this bad?
+These methods do the same thing as `_.clone()` but may be confusing as
+to why we are calling `to_vec` on something that is already a `Vec` or calling `to_owned` on something that is already owned.
+
+### Example
+```
+let a = vec![1, 2, 3];
+let b = a.to_vec();
+let c = a.to_owned();
+```
+Use instead:
+```
+let a = vec![1, 2, 3];
+let b = a.clone();
+let c = a.clone();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/implicit_hasher.txt b/src/tools/clippy/src/docs/implicit_hasher.txt
new file mode 100644
index 000000000000..0c1f76620f51
--- /dev/null
+++ b/src/tools/clippy/src/docs/implicit_hasher.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for public `impl` or `fn` missing generalization
+over different hashers and implicitly defaulting to the default hashing
+algorithm (`SipHash`).
+
+### Why is this bad?
+`HashMap` or `HashSet` with custom hashers cannot be
+used with them.
+
+### Known problems
+Suggestions for replacing constructors can contain
+false-positives. Also applying suggestions can require modification of other
+pieces of code, possibly including external crates.
+
+### Example
+```
+impl<K: Hash + Eq, V> Serialize for HashMap<K, V> { }
+
+pub fn foo(map: &mut HashMap<i32, i32>) { }
+```
+could be rewritten as
+```
+impl<K: Hash + Eq, V, S: BuildHasher> Serialize for HashMap<K, V, S> { }
+
+pub fn foo<S: BuildHasher>(map: &mut HashMap<i32, i32, S>) { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/implicit_return.txt b/src/tools/clippy/src/docs/implicit_return.txt
new file mode 100644
index 000000000000..ee65a636b38c
--- /dev/null
+++ b/src/tools/clippy/src/docs/implicit_return.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for missing return statements at the end of a block.
+
+### Why is this bad?
+Actually omitting the return keyword is idiomatic Rust code. Programmers
+coming from other languages might prefer the expressiveness of `return`. It's possible to miss
+the last returning statement because the only difference is a missing `;`. Especially in bigger
+code with multiple return paths having a `return` keyword makes it easier to find the
+corresponding statements.
+
+### Example
+```
+fn foo(x: usize) -> usize {
+    x
+}
+```
+add return
+```
+fn foo(x: usize) -> usize {
+    return x;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/implicit_saturating_sub.txt b/src/tools/clippy/src/docs/implicit_saturating_sub.txt
new file mode 100644
index 000000000000..03b47905a211
--- /dev/null
+++ b/src/tools/clippy/src/docs/implicit_saturating_sub.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for implicit saturating subtraction.
+
+### Why is this bad?
+Simplicity and readability. Instead we can easily use an builtin function.
+
+### Example
+```
+let mut i: u32 = end - start;
+
+if i != 0 {
+    i -= 1;
+}
+```
+
+Use instead:
+```
+let mut i: u32 = end - start;
+
+i = i.saturating_sub(1);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/imprecise_flops.txt b/src/tools/clippy/src/docs/imprecise_flops.txt
new file mode 100644
index 000000000000..e84d81cea98e
--- /dev/null
+++ b/src/tools/clippy/src/docs/imprecise_flops.txt
@@ -0,0 +1,23 @@
+### What it does
+Looks for floating-point expressions that
+can be expressed using built-in methods to improve accuracy
+at the cost of performance.
+
+### Why is this bad?
+Negatively impacts accuracy.
+
+### Example
+```
+let a = 3f32;
+let _ = a.powf(1.0 / 3.0);
+let _ = (1.0 + a).ln();
+let _ = a.exp() - 1.0;
+```
+
+Use instead:
+```
+let a = 3f32;
+let _ = a.cbrt();
+let _ = a.ln_1p();
+let _ = a.exp_m1();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inconsistent_digit_grouping.txt b/src/tools/clippy/src/docs/inconsistent_digit_grouping.txt
new file mode 100644
index 000000000000..aa0b072de1c4
--- /dev/null
+++ b/src/tools/clippy/src/docs/inconsistent_digit_grouping.txt
@@ -0,0 +1,17 @@
+### What it does
+Warns if an integral or floating-point constant is
+grouped inconsistently with underscores.
+
+### Why is this bad?
+Readers may incorrectly interpret inconsistently
+grouped digits.
+
+### Example
+```
+618_64_9189_73_511
+```
+
+Use instead:
+```
+61_864_918_973_511
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inconsistent_struct_constructor.txt b/src/tools/clippy/src/docs/inconsistent_struct_constructor.txt
new file mode 100644
index 000000000000..eb682109a54e
--- /dev/null
+++ b/src/tools/clippy/src/docs/inconsistent_struct_constructor.txt
@@ -0,0 +1,40 @@
+### What it does
+Checks for struct constructors where all fields are shorthand and
+the order of the field init shorthand in the constructor is inconsistent
+with the order in the struct definition.
+
+### Why is this bad?
+Since the order of fields in a constructor doesn't affect the
+resulted instance as the below example indicates,
+
+```
+#[derive(Debug, PartialEq, Eq)]
+struct Foo {
+    x: i32,
+    y: i32,
+}
+let x = 1;
+let y = 2;
+
+// This assertion never fails:
+assert_eq!(Foo { x, y }, Foo { y, x });
+```
+
+inconsistent order can be confusing and decreases readability and consistency.
+
+### Example
+```
+struct Foo {
+    x: i32,
+    y: i32,
+}
+let x = 1;
+let y = 2;
+
+Foo { y, x };
+```
+
+Use instead:
+```
+Foo { x, y };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/index_refutable_slice.txt b/src/tools/clippy/src/docs/index_refutable_slice.txt
new file mode 100644
index 000000000000..8a7d52761af8
--- /dev/null
+++ b/src/tools/clippy/src/docs/index_refutable_slice.txt
@@ -0,0 +1,29 @@
+### What it does
+The lint checks for slice bindings in patterns that are only used to
+access individual slice values.
+
+### Why is this bad?
+Accessing slice values using indices can lead to panics. Using refutable
+patterns can avoid these. Binding to individual values also improves the
+readability as they can be named.
+
+### Limitations
+This lint currently only checks for immutable access inside `if let`
+patterns.
+
+### Example
+```
+let slice: Option<&[u32]> = Some(&[1, 2, 3]);
+
+if let Some(slice) = slice {
+    println!("{}", slice[0]);
+}
+```
+Use instead:
+```
+let slice: Option<&[u32]> = Some(&[1, 2, 3]);
+
+if let Some(&[first, ..]) = slice {
+    println!("{}", first);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/indexing_slicing.txt b/src/tools/clippy/src/docs/indexing_slicing.txt
new file mode 100644
index 000000000000..76ca6ed318b3
--- /dev/null
+++ b/src/tools/clippy/src/docs/indexing_slicing.txt
@@ -0,0 +1,33 @@
+### What it does
+Checks for usage of indexing or slicing. Arrays are special cases, this lint
+does report on arrays if we can tell that slicing operations are in bounds and does not
+lint on constant `usize` indexing on arrays because that is handled by rustc's `const_err` lint.
+
+### Why is this bad?
+Indexing and slicing can panic at runtime and there are
+safe alternatives.
+
+### Example
+```
+// Vector
+let x = vec![0; 5];
+
+x[2];
+&x[2..100];
+
+// Array
+let y = [0, 1, 2, 3];
+
+&y[10..100];
+&y[10..];
+```
+
+Use instead:
+```
+
+x.get(2);
+x.get(2..100);
+
+y.get(10);
+y.get(10..100);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ineffective_bit_mask.txt b/src/tools/clippy/src/docs/ineffective_bit_mask.txt
new file mode 100644
index 000000000000..f6e7ef556215
--- /dev/null
+++ b/src/tools/clippy/src/docs/ineffective_bit_mask.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for bit masks in comparisons which can be removed
+without changing the outcome. The basic structure can be seen in the
+following table:
+
+|Comparison| Bit Op   |Example     |equals |
+|----------|----------|------------|-------|
+|`>` / `<=`|`\|` / `^`|`x \| 2 > 3`|`x > 3`|
+|`<` / `>=`|`\|` / `^`|`x ^ 1 < 4` |`x < 4`|
+
+### Why is this bad?
+Not equally evil as [`bad_bit_mask`](#bad_bit_mask),
+but still a bit misleading, because the bit mask is ineffective.
+
+### Known problems
+False negatives: This lint will only match instances
+where we have figured out the math (which is for a power-of-two compared
+value). This means things like `x | 1 >= 7` (which would be better written
+as `x >= 6`) will not be reported (but bit masks like this are fairly
+uncommon).
+
+### Example
+```
+if (x | 1 > 3) {  }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inefficient_to_string.txt b/src/tools/clippy/src/docs/inefficient_to_string.txt
new file mode 100644
index 000000000000..f7061d1ce7b0
--- /dev/null
+++ b/src/tools/clippy/src/docs/inefficient_to_string.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for usage of `.to_string()` on an `&&T` where
+`T` implements `ToString` directly (like `&&str` or `&&String`).
+
+### Why is this bad?
+This bypasses the specialized implementation of
+`ToString` and instead goes through the more expensive string formatting
+facilities.
+
+### Example
+```
+// Generic implementation for `T: Display` is used (slow)
+["foo", "bar"].iter().map(|s| s.to_string());
+
+// OK, the specialized impl is used
+["foo", "bar"].iter().map(|&s| s.to_string());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/infallible_destructuring_match.txt b/src/tools/clippy/src/docs/infallible_destructuring_match.txt
new file mode 100644
index 000000000000..4b5d3c4ba6c4
--- /dev/null
+++ b/src/tools/clippy/src/docs/infallible_destructuring_match.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for matches being used to destructure a single-variant enum
+or tuple struct where a `let` will suffice.
+
+### Why is this bad?
+Just readability – `let` doesn't nest, whereas a `match` does.
+
+### Example
+```
+enum Wrapper {
+    Data(i32),
+}
+
+let wrapper = Wrapper::Data(42);
+
+let data = match wrapper {
+    Wrapper::Data(i) => i,
+};
+```
+
+The correct use would be:
+```
+enum Wrapper {
+    Data(i32),
+}
+
+let wrapper = Wrapper::Data(42);
+let Wrapper::Data(data) = wrapper;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/infinite_iter.txt b/src/tools/clippy/src/docs/infinite_iter.txt
new file mode 100644
index 000000000000..8a22fabc5492
--- /dev/null
+++ b/src/tools/clippy/src/docs/infinite_iter.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for iteration that is guaranteed to be infinite.
+
+### Why is this bad?
+While there may be places where this is acceptable
+(e.g., in event streams), in most cases this is simply an error.
+
+### Example
+```
+use std::iter;
+
+iter::repeat(1_u8).collect::<Vec<_>>();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inherent_to_string.txt b/src/tools/clippy/src/docs/inherent_to_string.txt
new file mode 100644
index 000000000000..b18e600e9e67
--- /dev/null
+++ b/src/tools/clippy/src/docs/inherent_to_string.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
+
+### Why is this bad?
+This method is also implicitly defined if a type implements the `Display` trait. As the functionality of `Display` is much more versatile, it should be preferred.
+
+### Example
+```
+pub struct A;
+
+impl A {
+    pub fn to_string(&self) -> String {
+        "I am A".to_string()
+    }
+}
+```
+
+Use instead:
+```
+use std::fmt;
+
+pub struct A;
+
+impl fmt::Display for A {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "I am A")
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inherent_to_string_shadow_display.txt b/src/tools/clippy/src/docs/inherent_to_string_shadow_display.txt
new file mode 100644
index 000000000000..a4bd0b622c4f
--- /dev/null
+++ b/src/tools/clippy/src/docs/inherent_to_string_shadow_display.txt
@@ -0,0 +1,37 @@
+### What it does
+Checks for the definition of inherent methods with a signature of `to_string(&self) -> String` and if the type implementing this method also implements the `Display` trait.
+
+### Why is this bad?
+This method is also implicitly defined if a type implements the `Display` trait. The less versatile inherent method will then shadow the implementation introduced by `Display`.
+
+### Example
+```
+use std::fmt;
+
+pub struct A;
+
+impl A {
+    pub fn to_string(&self) -> String {
+        "I am A".to_string()
+    }
+}
+
+impl fmt::Display for A {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "I am A, too")
+    }
+}
+```
+
+Use instead:
+```
+use std::fmt;
+
+pub struct A;
+
+impl fmt::Display for A {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "I am A")
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/init_numbered_fields.txt b/src/tools/clippy/src/docs/init_numbered_fields.txt
new file mode 100644
index 000000000000..ba40af6a5fa5
--- /dev/null
+++ b/src/tools/clippy/src/docs/init_numbered_fields.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for tuple structs initialized with field syntax.
+It will however not lint if a base initializer is present.
+The lint will also ignore code in macros.
+
+### Why is this bad?
+This may be confusing to the uninitiated and adds no
+benefit as opposed to tuple initializers
+
+### Example
+```
+struct TupleStruct(u8, u16);
+
+let _ = TupleStruct {
+    0: 1,
+    1: 23,
+};
+
+// should be written as
+let base = TupleStruct(1, 23);
+
+// This is OK however
+let _ = TupleStruct { 0: 42, ..base };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inline_always.txt b/src/tools/clippy/src/docs/inline_always.txt
new file mode 100644
index 000000000000..7721da4c4cc7
--- /dev/null
+++ b/src/tools/clippy/src/docs/inline_always.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for items annotated with `#[inline(always)]`,
+unless the annotated function is empty or simply panics.
+
+### Why is this bad?
+While there are valid uses of this annotation (and once
+you know when to use it, by all means `allow` this lint), it's a common
+newbie-mistake to pepper one's code with it.
+
+As a rule of thumb, before slapping `#[inline(always)]` on a function,
+measure if that additional function call really affects your runtime profile
+sufficiently to make up for the increase in compile time.
+
+### Known problems
+False positives, big time. This lint is meant to be
+deactivated by everyone doing serious performance work. This means having
+done the measurement.
+
+### Example
+```
+#[inline(always)]
+fn not_quite_hot_code(..) { ... }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inline_asm_x86_att_syntax.txt b/src/tools/clippy/src/docs/inline_asm_x86_att_syntax.txt
new file mode 100644
index 000000000000..8eb49d122d89
--- /dev/null
+++ b/src/tools/clippy/src/docs/inline_asm_x86_att_syntax.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of AT&T x86 assembly syntax.
+
+### Why is this bad?
+The lint has been enabled to indicate a preference
+for Intel x86 assembly syntax.
+
+### Example
+
+```
+asm!("lea ({}), {}", in(reg) ptr, lateout(reg) _, options(att_syntax));
+```
+Use instead:
+```
+asm!("lea {}, [{}]", lateout(reg) _, in(reg) ptr);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inline_asm_x86_intel_syntax.txt b/src/tools/clippy/src/docs/inline_asm_x86_intel_syntax.txt
new file mode 100644
index 000000000000..5aa22c8ed235
--- /dev/null
+++ b/src/tools/clippy/src/docs/inline_asm_x86_intel_syntax.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of Intel x86 assembly syntax.
+
+### Why is this bad?
+The lint has been enabled to indicate a preference
+for AT&T x86 assembly syntax.
+
+### Example
+
+```
+asm!("lea {}, [{}]", lateout(reg) _, in(reg) ptr);
+```
+Use instead:
+```
+asm!("lea ({}), {}", in(reg) ptr, lateout(reg) _, options(att_syntax));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inline_fn_without_body.txt b/src/tools/clippy/src/docs/inline_fn_without_body.txt
new file mode 100644
index 000000000000..127c161aaa25
--- /dev/null
+++ b/src/tools/clippy/src/docs/inline_fn_without_body.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for `#[inline]` on trait methods without bodies
+
+### Why is this bad?
+Only implementations of trait methods may be inlined.
+The inline attribute is ignored for trait methods without bodies.
+
+### Example
+```
+trait Animal {
+    #[inline]
+    fn name(&self) -> &'static str;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/inspect_for_each.txt b/src/tools/clippy/src/docs/inspect_for_each.txt
new file mode 100644
index 000000000000..01a46d6c451f
--- /dev/null
+++ b/src/tools/clippy/src/docs/inspect_for_each.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for usage of `inspect().for_each()`.
+
+### Why is this bad?
+It is the same as performing the computation
+inside `inspect` at the beginning of the closure in `for_each`.
+
+### Example
+```
+[1,2,3,4,5].iter()
+.inspect(|&x| println!("inspect the number: {}", x))
+.for_each(|&x| {
+    assert!(x >= 0);
+});
+```
+Can be written as
+```
+[1,2,3,4,5].iter()
+.for_each(|&x| {
+    println!("inspect the number: {}", x);
+    assert!(x >= 0);
+});
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/int_plus_one.txt b/src/tools/clippy/src/docs/int_plus_one.txt
new file mode 100644
index 000000000000..1b68f3eeb64b
--- /dev/null
+++ b/src/tools/clippy/src/docs/int_plus_one.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for usage of `x >= y + 1` or `x - 1 >= y` (and `<=`) in a block
+
+### Why is this bad?
+Readability -- better to use `> y` instead of `>= y + 1`.
+
+### Example
+```
+if x >= y + 1 {}
+```
+
+Use instead:
+```
+if x > y {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/integer_arithmetic.txt b/src/tools/clippy/src/docs/integer_arithmetic.txt
new file mode 100644
index 000000000000..ea57a2ef97bf
--- /dev/null
+++ b/src/tools/clippy/src/docs/integer_arithmetic.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for integer arithmetic operations which could overflow or panic.
+
+Specifically, checks for any operators (`+`, `-`, `*`, `<<`, etc) which are capable
+of overflowing according to the [Rust
+Reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#overflow),
+or which can panic (`/`, `%`). No bounds analysis or sophisticated reasoning is
+attempted.
+
+### Why is this bad?
+Integer overflow will trigger a panic in debug builds or will wrap in
+release mode. Division by zero will cause a panic in either mode. In some applications one
+wants explicitly checked, wrapping or saturating arithmetic.
+
+### Example
+```
+a + 1;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/integer_division.txt b/src/tools/clippy/src/docs/integer_division.txt
new file mode 100644
index 000000000000..f6d3349810ed
--- /dev/null
+++ b/src/tools/clippy/src/docs/integer_division.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for division of integers
+
+### Why is this bad?
+When outside of some very specific algorithms,
+integer division is very often a mistake because it discards the
+remainder.
+
+### Example
+```
+let x = 3 / 2;
+println!("{}", x);
+```
+
+Use instead:
+```
+let x = 3f32 / 2f32;
+println!("{}", x);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/into_iter_on_ref.txt b/src/tools/clippy/src/docs/into_iter_on_ref.txt
new file mode 100644
index 000000000000..acb6bd474ebf
--- /dev/null
+++ b/src/tools/clippy/src/docs/into_iter_on_ref.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for `into_iter` calls on references which should be replaced by `iter`
+or `iter_mut`.
+
+### Why is this bad?
+Readability. Calling `into_iter` on a reference will not move out its
+content into the resulting iterator, which is confusing. It is better just call `iter` or
+`iter_mut` directly.
+
+### Example
+```
+(&vec).into_iter();
+```
+
+Use instead:
+```
+(&vec).iter();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/invalid_null_ptr_usage.txt b/src/tools/clippy/src/docs/invalid_null_ptr_usage.txt
new file mode 100644
index 000000000000..6fb3fa3f83d6
--- /dev/null
+++ b/src/tools/clippy/src/docs/invalid_null_ptr_usage.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint checks for invalid usages of `ptr::null`.
+
+### Why is this bad?
+This causes undefined behavior.
+
+### Example
+```
+// Undefined behavior
+unsafe { std::slice::from_raw_parts(ptr::null(), 0); }
+```
+
+Use instead:
+```
+unsafe { std::slice::from_raw_parts(NonNull::dangling().as_ptr(), 0); }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/invalid_regex.txt b/src/tools/clippy/src/docs/invalid_regex.txt
new file mode 100644
index 000000000000..6c9969b6e1a3
--- /dev/null
+++ b/src/tools/clippy/src/docs/invalid_regex.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks [regex](https://crates.io/crates/regex) creation
+(with `Regex::new`, `RegexBuilder::new`, or `RegexSet::new`) for correct
+regex syntax.
+
+### Why is this bad?
+This will lead to a runtime panic.
+
+### Example
+```
+Regex::new("(")
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/invalid_upcast_comparisons.txt b/src/tools/clippy/src/docs/invalid_upcast_comparisons.txt
new file mode 100644
index 000000000000..77cb03308037
--- /dev/null
+++ b/src/tools/clippy/src/docs/invalid_upcast_comparisons.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for comparisons where the relation is always either
+true or false, but where one side has been upcast so that the comparison is
+necessary. Only integer types are checked.
+
+### Why is this bad?
+An expression like `let x : u8 = ...; (x as u32) > 300`
+will mistakenly imply that it is possible for `x` to be outside the range of
+`u8`.
+
+### Known problems
+https://github.com/rust-lang/rust-clippy/issues/886
+
+### Example
+```
+let x: u8 = 1;
+(x as u32) > 300;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/invalid_utf8_in_unchecked.txt b/src/tools/clippy/src/docs/invalid_utf8_in_unchecked.txt
new file mode 100644
index 000000000000..afb5acbe9c51
--- /dev/null
+++ b/src/tools/clippy/src/docs/invalid_utf8_in_unchecked.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for `std::str::from_utf8_unchecked` with an invalid UTF-8 literal
+
+### Why is this bad?
+Creating such a `str` would result in undefined behavior
+
+### Example
+```
+unsafe {
+    std::str::from_utf8_unchecked(b"cl\x82ippy");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/invisible_characters.txt b/src/tools/clippy/src/docs/invisible_characters.txt
new file mode 100644
index 000000000000..3dda380911f9
--- /dev/null
+++ b/src/tools/clippy/src/docs/invisible_characters.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for invisible Unicode characters in the code.
+
+### Why is this bad?
+Having an invisible character in the code makes for all
+sorts of April fools, but otherwise is very much frowned upon.
+
+### Example
+You don't see it, but there may be a zero-width space or soft hyphen
+some­where in this text.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/is_digit_ascii_radix.txt b/src/tools/clippy/src/docs/is_digit_ascii_radix.txt
new file mode 100644
index 000000000000..9f11cf43054f
--- /dev/null
+++ b/src/tools/clippy/src/docs/is_digit_ascii_radix.txt
@@ -0,0 +1,20 @@
+### What it does
+Finds usages of [`char::is_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_digit) that
+can be replaced with [`is_ascii_digit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_ascii_digit) or
+[`is_ascii_hexdigit`](https://doc.rust-lang.org/stable/std/primitive.char.html#method.is_ascii_hexdigit).
+
+### Why is this bad?
+`is_digit(..)` is slower and requires specifying the radix.
+
+### Example
+```
+let c: char = '6';
+c.is_digit(10);
+c.is_digit(16);
+```
+Use instead:
+```
+let c: char = '6';
+c.is_ascii_digit();
+c.is_ascii_hexdigit();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/items_after_statements.txt b/src/tools/clippy/src/docs/items_after_statements.txt
new file mode 100644
index 000000000000..6fdfff50d20e
--- /dev/null
+++ b/src/tools/clippy/src/docs/items_after_statements.txt
@@ -0,0 +1,37 @@
+### What it does
+Checks for items declared after some statement in a block.
+
+### Why is this bad?
+Items live for the entire scope they are declared
+in. But statements are processed in order. This might cause confusion as
+it's hard to figure out which item is meant in a statement.
+
+### Example
+```
+fn foo() {
+    println!("cake");
+}
+
+fn main() {
+    foo(); // prints "foo"
+    fn foo() {
+        println!("foo");
+    }
+    foo(); // prints "foo"
+}
+```
+
+Use instead:
+```
+fn foo() {
+    println!("cake");
+}
+
+fn main() {
+    fn foo() {
+        println!("foo");
+    }
+    foo(); // prints "foo"
+    foo(); // prints "foo"
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_cloned_collect.txt b/src/tools/clippy/src/docs/iter_cloned_collect.txt
new file mode 100644
index 000000000000..90dc9ebb40f0
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_cloned_collect.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for the use of `.cloned().collect()` on slice to
+create a `Vec`.
+
+### Why is this bad?
+`.to_vec()` is clearer
+
+### Example
+```
+let s = [1, 2, 3, 4, 5];
+let s2: Vec<isize> = s[..].iter().cloned().collect();
+```
+The better use would be:
+```
+let s = [1, 2, 3, 4, 5];
+let s2: Vec<isize> = s.to_vec();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_count.txt b/src/tools/clippy/src/docs/iter_count.txt
new file mode 100644
index 000000000000..f3db4a26c299
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_count.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for the use of `.iter().count()`.
+
+### Why is this bad?
+`.len()` is more efficient and more
+readable.
+
+### Example
+```
+let some_vec = vec![0, 1, 2, 3];
+
+some_vec.iter().count();
+&some_vec[..].iter().count();
+```
+
+Use instead:
+```
+let some_vec = vec![0, 1, 2, 3];
+
+some_vec.len();
+&some_vec[..].len();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_kv_map.txt b/src/tools/clippy/src/docs/iter_kv_map.txt
new file mode 100644
index 000000000000..a063c8195ef5
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_kv_map.txt
@@ -0,0 +1,22 @@
+### What it does
+
+Checks for iterating a map (`HashMap` or `BTreeMap`) and
+ignoring either the keys or values.
+
+### Why is this bad?
+
+Readability. There are `keys` and `values` methods that
+can be used to express that we only need the keys or the values.
+
+### Example
+
+```
+let map: HashMap<u32, u32> = HashMap::new();
+let values = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+```
+
+Use instead:
+```
+let map: HashMap<u32, u32> = HashMap::new();
+let values = map.values().collect::<Vec<_>>();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_next_loop.txt b/src/tools/clippy/src/docs/iter_next_loop.txt
new file mode 100644
index 000000000000..b33eb39d6e1d
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_next_loop.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for loops on `x.next()`.
+
+### Why is this bad?
+`next()` returns either `Some(value)` if there was a
+value, or `None` otherwise. The insidious thing is that `Option<_>`
+implements `IntoIterator`, so that possibly one value will be iterated,
+leading to some hard to find bugs. No one will want to write such code
+[except to win an Underhanded Rust
+Contest](https://www.reddit.com/r/rust/comments/3hb0wm/underhanded_rust_contest/cu5yuhr).
+
+### Example
+```
+for x in y.next() {
+    ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_next_slice.txt b/src/tools/clippy/src/docs/iter_next_slice.txt
new file mode 100644
index 000000000000..1cea25eaf301
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_next_slice.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of `iter().next()` on a Slice or an Array
+
+### Why is this bad?
+These can be shortened into `.get()`
+
+### Example
+```
+a[2..].iter().next();
+b.iter().next();
+```
+should be written as:
+```
+a.get(2);
+b.get(0);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_not_returning_iterator.txt b/src/tools/clippy/src/docs/iter_not_returning_iterator.txt
new file mode 100644
index 000000000000..0ca862910a6f
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_not_returning_iterator.txt
@@ -0,0 +1,26 @@
+### What it does
+Detects methods named `iter` or `iter_mut` that do not have a return type that implements `Iterator`.
+
+### Why is this bad?
+Methods named `iter` or `iter_mut` conventionally return an `Iterator`.
+
+### Example
+```
+// `String` does not implement `Iterator`
+struct Data {}
+impl Data {
+    fn iter(&self) -> String {
+        todo!()
+    }
+}
+```
+Use instead:
+```
+use std::str::Chars;
+struct Data {}
+impl Data {
+   fn iter(&self) -> Chars<'static> {
+       todo!()
+   }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_nth.txt b/src/tools/clippy/src/docs/iter_nth.txt
new file mode 100644
index 000000000000..3d67d583ffde
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_nth.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for use of `.iter().nth()` (and the related
+`.iter_mut().nth()`) on standard library types with *O*(1) element access.
+
+### Why is this bad?
+`.get()` and `.get_mut()` are more efficient and more
+readable.
+
+### Example
+```
+let some_vec = vec![0, 1, 2, 3];
+let bad_vec = some_vec.iter().nth(3);
+let bad_slice = &some_vec[..].iter().nth(3);
+```
+The correct use would be:
+```
+let some_vec = vec![0, 1, 2, 3];
+let bad_vec = some_vec.get(3);
+let bad_slice = &some_vec[..].get(3);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_nth_zero.txt b/src/tools/clippy/src/docs/iter_nth_zero.txt
new file mode 100644
index 000000000000..8efe47a16a10
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_nth_zero.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for the use of `iter.nth(0)`.
+
+### Why is this bad?
+`iter.next()` is equivalent to
+`iter.nth(0)`, as they both consume the next element,
+ but is more readable.
+
+### Example
+```
+let x = s.iter().nth(0);
+```
+
+Use instead:
+```
+let x = s.iter().next();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_on_empty_collections.txt b/src/tools/clippy/src/docs/iter_on_empty_collections.txt
new file mode 100644
index 000000000000..87c4ec12afae
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_on_empty_collections.txt
@@ -0,0 +1,25 @@
+### What it does
+
+Checks for calls to `iter`, `iter_mut` or `into_iter` on empty collections
+
+### Why is this bad?
+
+It is simpler to use the empty function from the standard library:
+
+### Example
+
+```
+use std::{slice, option};
+let a: slice::Iter<i32> = [].iter();
+let f: option::IntoIter<i32> = None.into_iter();
+```
+Use instead:
+```
+use std::iter;
+let a: iter::Empty<i32> = iter::empty();
+let b: iter::Empty<i32> = iter::empty();
+```
+
+### Known problems
+
+The type of the resulting iterator might become incompatible with its usage
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_on_single_items.txt b/src/tools/clippy/src/docs/iter_on_single_items.txt
new file mode 100644
index 000000000000..d0388f25d045
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_on_single_items.txt
@@ -0,0 +1,24 @@
+### What it does
+
+Checks for calls to `iter`, `iter_mut` or `into_iter` on collections containing a single item
+
+### Why is this bad?
+
+It is simpler to use the once function from the standard library:
+
+### Example
+
+```
+let a = [123].iter();
+let b = Some(123).into_iter();
+```
+Use instead:
+```
+use std::iter;
+let a = iter::once(&123);
+let b = iter::once(123);
+```
+
+### Known problems
+
+The type of the resulting iterator might become incompatible with its usage
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_overeager_cloned.txt b/src/tools/clippy/src/docs/iter_overeager_cloned.txt
new file mode 100644
index 000000000000..2f902a0c2db4
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_overeager_cloned.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usage of `_.cloned().<func>()` where call to `.cloned()` can be postponed.
+
+### Why is this bad?
+It's often inefficient to clone all elements of an iterator, when eventually, only some
+of them will be consumed.
+
+### Known Problems
+This `lint` removes the side of effect of cloning items in the iterator.
+A code that relies on that side-effect could fail.
+
+### Examples
+```
+vec.iter().cloned().take(10);
+vec.iter().cloned().last();
+```
+
+Use instead:
+```
+vec.iter().take(10).cloned();
+vec.iter().last().cloned();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_skip_next.txt b/src/tools/clippy/src/docs/iter_skip_next.txt
new file mode 100644
index 000000000000..da226b041cf2
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_skip_next.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for use of `.skip(x).next()` on iterators.
+
+### Why is this bad?
+`.nth(x)` is cleaner
+
+### Example
+```
+let some_vec = vec![0, 1, 2, 3];
+let bad_vec = some_vec.iter().skip(3).next();
+let bad_slice = &some_vec[..].iter().skip(3).next();
+```
+The correct use would be:
+```
+let some_vec = vec![0, 1, 2, 3];
+let bad_vec = some_vec.iter().nth(3);
+let bad_slice = &some_vec[..].iter().nth(3);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iter_with_drain.txt b/src/tools/clippy/src/docs/iter_with_drain.txt
new file mode 100644
index 000000000000..2c52b99f7a5c
--- /dev/null
+++ b/src/tools/clippy/src/docs/iter_with_drain.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for use of `.drain(..)` on `Vec` and `VecDeque` for iteration.
+
+### Why is this bad?
+`.into_iter()` is simpler with better performance.
+
+### Example
+```
+let mut foo = vec![0, 1, 2, 3];
+let bar: HashSet<usize> = foo.drain(..).collect();
+```
+Use instead:
+```
+let foo = vec![0, 1, 2, 3];
+let bar: HashSet<usize> = foo.into_iter().collect();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/iterator_step_by_zero.txt b/src/tools/clippy/src/docs/iterator_step_by_zero.txt
new file mode 100644
index 000000000000..73ecc99acfcb
--- /dev/null
+++ b/src/tools/clippy/src/docs/iterator_step_by_zero.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for calling `.step_by(0)` on iterators which panics.
+
+### Why is this bad?
+This very much looks like an oversight. Use `panic!()` instead if you
+actually intend to panic.
+
+### Example
+```
+for x in (0..100).step_by(0) {
+    //..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/just_underscores_and_digits.txt b/src/tools/clippy/src/docs/just_underscores_and_digits.txt
new file mode 100644
index 000000000000..a8790bcf25be
--- /dev/null
+++ b/src/tools/clippy/src/docs/just_underscores_and_digits.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks if you have variables whose name consists of just
+underscores and digits.
+
+### Why is this bad?
+It's hard to memorize what a variable means without a
+descriptive name.
+
+### Example
+```
+let _1 = 1;
+let ___1 = 1;
+let __1___2 = 11;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/large_const_arrays.txt b/src/tools/clippy/src/docs/large_const_arrays.txt
new file mode 100644
index 000000000000..71f67854f2a1
--- /dev/null
+++ b/src/tools/clippy/src/docs/large_const_arrays.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for large `const` arrays that should
+be defined as `static` instead.
+
+### Why is this bad?
+Performance: const variables are inlined upon use.
+Static items result in only one instance and has a fixed location in memory.
+
+### Example
+```
+pub const a = [0u32; 1_000_000];
+```
+
+Use instead:
+```
+pub static a = [0u32; 1_000_000];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/large_digit_groups.txt b/src/tools/clippy/src/docs/large_digit_groups.txt
new file mode 100644
index 000000000000..f60b19345af4
--- /dev/null
+++ b/src/tools/clippy/src/docs/large_digit_groups.txt
@@ -0,0 +1,12 @@
+### What it does
+Warns if the digits of an integral or floating-point
+constant are grouped into groups that
+are too large.
+
+### Why is this bad?
+Negatively impacts readability.
+
+### Example
+```
+let x: u64 = 6186491_8973511;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/large_enum_variant.txt b/src/tools/clippy/src/docs/large_enum_variant.txt
new file mode 100644
index 000000000000..1f95430790d2
--- /dev/null
+++ b/src/tools/clippy/src/docs/large_enum_variant.txt
@@ -0,0 +1,41 @@
+### What it does
+Checks for large size differences between variants on
+`enum`s.
+
+### Why is this bad?
+Enum size is bounded by the largest variant. Having one
+large variant can penalize the memory layout of that enum.
+
+### Known problems
+This lint obviously cannot take the distribution of
+variants in your running program into account. It is possible that the
+smaller variants make up less than 1% of all instances, in which case
+the overhead is negligible and the boxing is counter-productive. Always
+measure the change this lint suggests.
+
+For types that implement `Copy`, the suggestion to `Box` a variant's
+data would require removing the trait impl. The types can of course
+still be `Clone`, but that is worse ergonomically. Depending on the
+use case it may be possible to store the large data in an auxiliary
+structure (e.g. Arena or ECS).
+
+The lint will ignore the impact of generic types to the type layout by
+assuming every type parameter is zero-sized. Depending on your use case,
+this may lead to a false positive.
+
+### Example
+```
+enum Test {
+    A(i32),
+    B([i32; 8000]),
+}
+```
+
+Use instead:
+```
+// Possibly better
+enum Test2 {
+    A(i32),
+    B(Box<[i32; 8000]>),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/large_include_file.txt b/src/tools/clippy/src/docs/large_include_file.txt
new file mode 100644
index 000000000000..b2a54bd2eb5c
--- /dev/null
+++ b/src/tools/clippy/src/docs/large_include_file.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for the inclusion of large files via `include_bytes!()`
+and `include_str!()`
+
+### Why is this bad?
+Including large files can increase the size of the binary
+
+### Example
+```
+let included_str = include_str!("very_large_file.txt");
+let included_bytes = include_bytes!("very_large_file.txt");
+```
+
+Use instead:
+```
+use std::fs;
+
+// You can load the file at runtime
+let string = fs::read_to_string("very_large_file.txt")?;
+let bytes = fs::read("very_large_file.txt")?;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/large_stack_arrays.txt b/src/tools/clippy/src/docs/large_stack_arrays.txt
new file mode 100644
index 000000000000..4a6f34785b0e
--- /dev/null
+++ b/src/tools/clippy/src/docs/large_stack_arrays.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for local arrays that may be too large.
+
+### Why is this bad?
+Large local arrays may cause stack overflow.
+
+### Example
+```
+let a = [0u32; 1_000_000];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/large_types_passed_by_value.txt b/src/tools/clippy/src/docs/large_types_passed_by_value.txt
new file mode 100644
index 000000000000..bca07f3ac61b
--- /dev/null
+++ b/src/tools/clippy/src/docs/large_types_passed_by_value.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for functions taking arguments by value, where
+the argument type is `Copy` and large enough to be worth considering
+passing by reference. Does not trigger if the function is being exported,
+because that might induce API breakage, if the parameter is declared as mutable,
+or if the argument is a `self`.
+
+### Why is this bad?
+Arguments passed by value might result in an unnecessary
+shallow copy, taking up more space in the stack and requiring a call to
+`memcpy`, which can be expensive.
+
+### Example
+```
+#[derive(Clone, Copy)]
+struct TooLarge([u8; 2048]);
+
+fn foo(v: TooLarge) {}
+```
+
+Use instead:
+```
+fn foo(v: &TooLarge) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/len_without_is_empty.txt b/src/tools/clippy/src/docs/len_without_is_empty.txt
new file mode 100644
index 000000000000..47a2e8575228
--- /dev/null
+++ b/src/tools/clippy/src/docs/len_without_is_empty.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for items that implement `.len()` but not
+`.is_empty()`.
+
+### Why is this bad?
+It is good custom to have both methods, because for
+some data structures, asking about the length will be a costly operation,
+whereas `.is_empty()` can usually answer in constant time. Also it used to
+lead to false positives on the [`len_zero`](#len_zero) lint – currently that
+lint will ignore such entities.
+
+### Example
+```
+impl X {
+    pub fn len(&self) -> usize {
+        ..
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/len_zero.txt b/src/tools/clippy/src/docs/len_zero.txt
new file mode 100644
index 000000000000..664124bd391d
--- /dev/null
+++ b/src/tools/clippy/src/docs/len_zero.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for getting the length of something via `.len()`
+just to compare to zero, and suggests using `.is_empty()` where applicable.
+
+### Why is this bad?
+Some structures can answer `.is_empty()` much faster
+than calculating their length. So it is good to get into the habit of using
+`.is_empty()`, and having it is cheap.
+Besides, it makes the intent clearer than a manual comparison in some contexts.
+
+### Example
+```
+if x.len() == 0 {
+    ..
+}
+if y.len() != 0 {
+    ..
+}
+```
+instead use
+```
+if x.is_empty() {
+    ..
+}
+if !y.is_empty() {
+    ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/let_and_return.txt b/src/tools/clippy/src/docs/let_and_return.txt
new file mode 100644
index 000000000000..eba5a90ddd66
--- /dev/null
+++ b/src/tools/clippy/src/docs/let_and_return.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for `let`-bindings, which are subsequently
+returned.
+
+### Why is this bad?
+It is just extraneous code. Remove it to make your code
+more rusty.
+
+### Example
+```
+fn foo() -> String {
+    let x = String::new();
+    x
+}
+```
+instead, use
+```
+fn foo() -> String {
+    String::new()
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/let_underscore_drop.txt b/src/tools/clippy/src/docs/let_underscore_drop.txt
new file mode 100644
index 000000000000..29ce9bf50ce6
--- /dev/null
+++ b/src/tools/clippy/src/docs/let_underscore_drop.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for `let _ = <expr>`
+where expr has a type that implements `Drop`
+
+### Why is this bad?
+This statement immediately drops the initializer
+expression instead of extending its lifetime to the end of the scope, which
+is often not intended. To extend the expression's lifetime to the end of the
+scope, use an underscore-prefixed name instead (i.e. _var). If you want to
+explicitly drop the expression, `std::mem::drop` conveys your intention
+better and is less error-prone.
+
+### Example
+```
+{
+    let _ = DroppableItem;
+    //                   ^ dropped here
+    /* more code */
+}
+```
+
+Use instead:
+```
+{
+    let _droppable = DroppableItem;
+    /* more code */
+    // dropped at end of scope
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/let_underscore_lock.txt b/src/tools/clippy/src/docs/let_underscore_lock.txt
new file mode 100644
index 000000000000..bd8217fb58b3
--- /dev/null
+++ b/src/tools/clippy/src/docs/let_underscore_lock.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for `let _ = sync_lock`.
+This supports `mutex` and `rwlock` in `std::sync` and `parking_lot`.
+
+### Why is this bad?
+This statement immediately drops the lock instead of
+extending its lifetime to the end of the scope, which is often not intended.
+To extend lock lifetime to the end of the scope, use an underscore-prefixed
+name instead (i.e. _lock). If you want to explicitly drop the lock,
+`std::mem::drop` conveys your intention better and is less error-prone.
+
+### Example
+```
+let _ = mutex.lock();
+```
+
+Use instead:
+```
+let _lock = mutex.lock();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/let_underscore_must_use.txt b/src/tools/clippy/src/docs/let_underscore_must_use.txt
new file mode 100644
index 000000000000..270b81d9a4c4
--- /dev/null
+++ b/src/tools/clippy/src/docs/let_underscore_must_use.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for `let _ = <expr>` where expr is `#[must_use]`
+
+### Why is this bad?
+It's better to explicitly handle the value of a `#[must_use]`
+expr
+
+### Example
+```
+fn f() -> Result<u32, u32> {
+    Ok(0)
+}
+
+let _ = f();
+// is_ok() is marked #[must_use]
+let _ = f().is_ok();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/let_unit_value.txt b/src/tools/clippy/src/docs/let_unit_value.txt
new file mode 100644
index 000000000000..bc16d5b3d81b
--- /dev/null
+++ b/src/tools/clippy/src/docs/let_unit_value.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for binding a unit value.
+
+### Why is this bad?
+A unit value cannot usefully be used anywhere. So
+binding one is kind of pointless.
+
+### Example
+```
+let x = {
+    1;
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/linkedlist.txt b/src/tools/clippy/src/docs/linkedlist.txt
new file mode 100644
index 000000000000..986ff1369e3c
--- /dev/null
+++ b/src/tools/clippy/src/docs/linkedlist.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for usage of any `LinkedList`, suggesting to use a
+`Vec` or a `VecDeque` (formerly called `RingBuf`).
+
+### Why is this bad?
+Gankro says:
+
+> The TL;DR of `LinkedList` is that it's built on a massive amount of
+pointers and indirection.
+> It wastes memory, it has terrible cache locality, and is all-around slow.
+`RingBuf`, while
+> "only" amortized for push/pop, should be faster in the general case for
+almost every possible
+> workload, and isn't even amortized at all if you can predict the capacity
+you need.
+>
+> `LinkedList`s are only really good if you're doing a lot of merging or
+splitting of lists.
+> This is because they can just mangle some pointers instead of actually
+copying the data. Even
+> if you're doing a lot of insertion in the middle of the list, `RingBuf`
+can still be better
+> because of how expensive it is to seek to the middle of a `LinkedList`.
+
+### Known problems
+False positives – the instances where using a
+`LinkedList` makes sense are few and far between, but they can still happen.
+
+### Example
+```
+let x: LinkedList<usize> = LinkedList::new();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/lossy_float_literal.txt b/src/tools/clippy/src/docs/lossy_float_literal.txt
new file mode 100644
index 000000000000..bbcb9115ea62
--- /dev/null
+++ b/src/tools/clippy/src/docs/lossy_float_literal.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for whole number float literals that
+cannot be represented as the underlying type without loss.
+
+### Why is this bad?
+Rust will silently lose precision during
+conversion to a float.
+
+### Example
+```
+let _: f32 = 16_777_217.0; // 16_777_216.0
+```
+
+Use instead:
+```
+let _: f32 = 16_777_216.0;
+let _: f64 = 16_777_217.0;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/macro_use_imports.txt b/src/tools/clippy/src/docs/macro_use_imports.txt
new file mode 100644
index 000000000000..6a8180a60bc6
--- /dev/null
+++ b/src/tools/clippy/src/docs/macro_use_imports.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for `#[macro_use] use...`.
+
+### Why is this bad?
+Since the Rust 2018 edition you can import
+macro's directly, this is considered idiomatic.
+
+### Example
+```
+#[macro_use]
+use some_macro;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/main_recursion.txt b/src/tools/clippy/src/docs/main_recursion.txt
new file mode 100644
index 000000000000..e49becd15bbd
--- /dev/null
+++ b/src/tools/clippy/src/docs/main_recursion.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for recursion using the entrypoint.
+
+### Why is this bad?
+Apart from special setups (which we could detect following attributes like #![no_std]),
+recursing into main() seems like an unintuitive anti-pattern we should be able to detect.
+
+### Example
+```
+fn main() {
+    main();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_assert.txt b/src/tools/clippy/src/docs/manual_assert.txt
new file mode 100644
index 000000000000..93653081a2ce
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_assert.txt
@@ -0,0 +1,18 @@
+### What it does
+Detects `if`-then-`panic!` that can be replaced with `assert!`.
+
+### Why is this bad?
+`assert!` is simpler than `if`-then-`panic!`.
+
+### Example
+```
+let sad_people: Vec<&str> = vec![];
+if !sad_people.is_empty() {
+    panic!("there are sad people: {:?}", sad_people);
+}
+```
+Use instead:
+```
+let sad_people: Vec<&str> = vec![];
+assert!(sad_people.is_empty(), "there are sad people: {:?}", sad_people);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_async_fn.txt b/src/tools/clippy/src/docs/manual_async_fn.txt
new file mode 100644
index 000000000000..d01ac402e0d2
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_async_fn.txt
@@ -0,0 +1,16 @@
+### What it does
+It checks for manual implementations of `async` functions.
+
+### Why is this bad?
+It's more idiomatic to use the dedicated syntax.
+
+### Example
+```
+use std::future::Future;
+
+fn foo() -> impl Future<Output = i32> { async { 42 } }
+```
+Use instead:
+```
+async fn foo() -> i32 { 42 }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_bits.txt b/src/tools/clippy/src/docs/manual_bits.txt
new file mode 100644
index 000000000000..b96c2eb151d4
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_bits.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for uses of `std::mem::size_of::<T>() * 8` when
+`T::BITS` is available.
+
+### Why is this bad?
+Can be written as the shorter `T::BITS`.
+
+### Example
+```
+std::mem::size_of::<usize>() * 8;
+```
+Use instead:
+```
+usize::BITS as usize;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_filter_map.txt b/src/tools/clippy/src/docs/manual_filter_map.txt
new file mode 100644
index 000000000000..3b6860798ff5
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_filter_map.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `_.filter(_).map(_)` that can be written more simply
+as `filter_map(_)`.
+
+### Why is this bad?
+Redundant code in the `filter` and `map` operations is poor style and
+less performant.
+
+### Example
+```
+(0_i32..10)
+    .filter(|n| n.checked_add(1).is_some())
+    .map(|n| n.checked_add(1).unwrap());
+```
+
+Use instead:
+```
+(0_i32..10).filter_map(|n| n.checked_add(1));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_find.txt b/src/tools/clippy/src/docs/manual_find.txt
new file mode 100644
index 000000000000..e3e07a2771f9
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_find.txt
@@ -0,0 +1,24 @@
+### What it does
+Check for manual implementations of Iterator::find
+
+### Why is this bad?
+It doesn't affect performance, but using `find` is shorter and easier to read.
+
+### Example
+
+```
+fn example(arr: Vec<i32>) -> Option<i32> {
+    for el in arr {
+        if el == 1 {
+            return Some(el);
+        }
+    }
+    None
+}
+```
+Use instead:
+```
+fn example(arr: Vec<i32>) -> Option<i32> {
+    arr.into_iter().find(|&el| el == 1)
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_find_map.txt b/src/tools/clippy/src/docs/manual_find_map.txt
new file mode 100644
index 000000000000..83b22060c0e1
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_find_map.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `_.find(_).map(_)` that can be written more simply
+as `find_map(_)`.
+
+### Why is this bad?
+Redundant code in the `find` and `map` operations is poor style and
+less performant.
+
+### Example
+```
+(0_i32..10)
+    .find(|n| n.checked_add(1).is_some())
+    .map(|n| n.checked_add(1).unwrap());
+```
+
+Use instead:
+```
+(0_i32..10).find_map(|n| n.checked_add(1));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_flatten.txt b/src/tools/clippy/src/docs/manual_flatten.txt
new file mode 100644
index 000000000000..62d5f3ec9357
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_flatten.txt
@@ -0,0 +1,25 @@
+### What it does
+Check for unnecessary `if let` usage in a for loop
+where only the `Some` or `Ok` variant of the iterator element is used.
+
+### Why is this bad?
+It is verbose and can be simplified
+by first calling the `flatten` method on the `Iterator`.
+
+### Example
+
+```
+let x = vec![Some(1), Some(2), Some(3)];
+for n in x {
+    if let Some(n) = n {
+        println!("{}", n);
+    }
+}
+```
+Use instead:
+```
+let x = vec![Some(1), Some(2), Some(3)];
+for n in x.into_iter().flatten() {
+    println!("{}", n);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_instant_elapsed.txt b/src/tools/clippy/src/docs/manual_instant_elapsed.txt
new file mode 100644
index 000000000000..dde3d493c70d
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_instant_elapsed.txt
@@ -0,0 +1,21 @@
+### What it does
+Lints subtraction between `Instant::now()` and another `Instant`.
+
+### Why is this bad?
+It is easy to accidentally write `prev_instant - Instant::now()`, which will always be 0ns
+as `Instant` subtraction saturates.
+
+`prev_instant.elapsed()` also more clearly signals intention.
+
+### Example
+```
+use std::time::Instant;
+let prev_instant = Instant::now();
+let duration = Instant::now() - prev_instant;
+```
+Use instead:
+```
+use std::time::Instant;
+let prev_instant = Instant::now();
+let duration = prev_instant.elapsed();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_map.txt b/src/tools/clippy/src/docs/manual_map.txt
new file mode 100644
index 000000000000..7f68ccd1037e
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_map.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for usages of `match` which could be implemented using `map`
+
+### Why is this bad?
+Using the `map` method is clearer and more concise.
+
+### Example
+```
+match Some(0) {
+    Some(x) => Some(x + 1),
+    None => None,
+};
+```
+Use instead:
+```
+Some(0).map(|x| x + 1);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_memcpy.txt b/src/tools/clippy/src/docs/manual_memcpy.txt
new file mode 100644
index 000000000000..d7690bf25866
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_memcpy.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for for-loops that manually copy items between
+slices that could be optimized by having a memcpy.
+
+### Why is this bad?
+It is not as fast as a memcpy.
+
+### Example
+```
+for i in 0..src.len() {
+    dst[i + 64] = src[i];
+}
+```
+
+Use instead:
+```
+dst[64..(src.len() + 64)].clone_from_slice(&src[..]);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_non_exhaustive.txt b/src/tools/clippy/src/docs/manual_non_exhaustive.txt
new file mode 100644
index 000000000000..fb021393bd7c
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_non_exhaustive.txt
@@ -0,0 +1,41 @@
+### What it does
+Checks for manual implementations of the non-exhaustive pattern.
+
+### Why is this bad?
+Using the #[non_exhaustive] attribute expresses better the intent
+and allows possible optimizations when applied to enums.
+
+### Example
+```
+struct S {
+    pub a: i32,
+    pub b: i32,
+    _c: (),
+}
+
+enum E {
+    A,
+    B,
+    #[doc(hidden)]
+    _C,
+}
+
+struct T(pub i32, pub i32, ());
+```
+Use instead:
+```
+#[non_exhaustive]
+struct S {
+    pub a: i32,
+    pub b: i32,
+}
+
+#[non_exhaustive]
+enum E {
+    A,
+    B,
+}
+
+#[non_exhaustive]
+struct T(pub i32, pub i32);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_ok_or.txt b/src/tools/clippy/src/docs/manual_ok_or.txt
new file mode 100644
index 000000000000..5accdf25965a
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_ok_or.txt
@@ -0,0 +1,19 @@
+### What it does
+
+Finds patterns that reimplement `Option::ok_or`.
+
+### Why is this bad?
+
+Concise code helps focusing on behavior instead of boilerplate.
+
+### Examples
+```
+let foo: Option<i32> = None;
+foo.map_or(Err("error"), |v| Ok(v));
+```
+
+Use instead:
+```
+let foo: Option<i32> = None;
+foo.ok_or("error");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_range_contains.txt b/src/tools/clippy/src/docs/manual_range_contains.txt
new file mode 100644
index 000000000000..0ade26951d38
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_range_contains.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for expressions like `x >= 3 && x < 8` that could
+be more readably expressed as `(3..8).contains(x)`.
+
+### Why is this bad?
+`contains` expresses the intent better and has less
+failure modes (such as fencepost errors or using `||` instead of `&&`).
+
+### Example
+```
+// given
+let x = 6;
+
+assert!(x >= 3 && x < 8);
+```
+Use instead:
+```
+assert!((3..8).contains(&x));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_rem_euclid.txt b/src/tools/clippy/src/docs/manual_rem_euclid.txt
new file mode 100644
index 000000000000..d3bb8c61304e
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_rem_euclid.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for an expression like `((x % 4) + 4) % 4` which is a common manual reimplementation
+of `x.rem_euclid(4)`.
+
+### Why is this bad?
+It's simpler and more readable.
+
+### Example
+```
+let x: i32 = 24;
+let rem = ((x % 4) + 4) % 4;
+```
+Use instead:
+```
+let x: i32 = 24;
+let rem = x.rem_euclid(4);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_retain.txt b/src/tools/clippy/src/docs/manual_retain.txt
new file mode 100644
index 000000000000..cd4f65a93fc3
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_retain.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for code to be replaced by `.retain()`.
+### Why is this bad?
+`.retain()` is simpler and avoids needless allocation.
+### Example
+```
+let mut vec = vec![0, 1, 2];
+vec = vec.iter().filter(|&x| x % 2 == 0).copied().collect();
+vec = vec.into_iter().filter(|x| x % 2 == 0).collect();
+```
+Use instead:
+```
+let mut vec = vec![0, 1, 2];
+vec.retain(|x| x % 2 == 0);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_saturating_arithmetic.txt b/src/tools/clippy/src/docs/manual_saturating_arithmetic.txt
new file mode 100644
index 000000000000..d9f5d3d11871
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_saturating_arithmetic.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for `.checked_add/sub(x).unwrap_or(MAX/MIN)`.
+
+### Why is this bad?
+These can be written simply with `saturating_add/sub` methods.
+
+### Example
+```
+let add = x.checked_add(y).unwrap_or(u32::MAX);
+let sub = x.checked_sub(y).unwrap_or(u32::MIN);
+```
+
+can be written using dedicated methods for saturating addition/subtraction as:
+
+```
+let add = x.saturating_add(y);
+let sub = x.saturating_sub(y);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_split_once.txt b/src/tools/clippy/src/docs/manual_split_once.txt
new file mode 100644
index 000000000000..291ae447de08
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_split_once.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for usages of `str::splitn(2, _)`
+
+### Why is this bad?
+`split_once` is both clearer in intent and slightly more efficient.
+
+### Example
+```
+let s = "key=value=add";
+let (key, value) = s.splitn(2, '=').next_tuple()?;
+let value = s.splitn(2, '=').nth(1)?;
+
+let mut parts = s.splitn(2, '=');
+let key = parts.next()?;
+let value = parts.next()?;
+```
+
+Use instead:
+```
+let s = "key=value=add";
+let (key, value) = s.split_once('=')?;
+let value = s.split_once('=')?.1;
+
+let (key, value) = s.split_once('=')?;
+```
+
+### Limitations
+The multiple statement variant currently only detects `iter.next()?`/`iter.next().unwrap()`
+in two separate `let` statements that immediately follow the `splitn()`
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_str_repeat.txt b/src/tools/clippy/src/docs/manual_str_repeat.txt
new file mode 100644
index 000000000000..1d4a7a48e203
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_str_repeat.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for manual implementations of `str::repeat`
+
+### Why is this bad?
+These are both harder to read, as well as less performant.
+
+### Example
+```
+let x: String = std::iter::repeat('x').take(10).collect();
+```
+
+Use instead:
+```
+let x: String = "x".repeat(10);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_string_new.txt b/src/tools/clippy/src/docs/manual_string_new.txt
new file mode 100644
index 000000000000..4cbc43f8f843
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_string_new.txt
@@ -0,0 +1,20 @@
+### What it does
+
+Checks for usage of `""` to create a `String`, such as `"".to_string()`, `"".to_owned()`,
+`String::from("")` and others.
+
+### Why is this bad?
+
+Different ways of creating an empty string makes your code less standardized, which can
+be confusing.
+
+### Example
+```
+let a = "".to_string();
+let b: String = "".into();
+```
+Use instead:
+```
+let a = String::new();
+let b = String::new();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_strip.txt b/src/tools/clippy/src/docs/manual_strip.txt
new file mode 100644
index 000000000000..f32d8e7a09bb
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_strip.txt
@@ -0,0 +1,24 @@
+### What it does
+Suggests using `strip_{prefix,suffix}` over `str::{starts,ends}_with` and slicing using
+the pattern's length.
+
+### Why is this bad?
+Using `str:strip_{prefix,suffix}` is safer and may have better performance as there is no
+slicing which may panic and the compiler does not need to insert this panic code. It is
+also sometimes more readable as it removes the need for duplicating or storing the pattern
+used by `str::{starts,ends}_with` and in the slicing.
+
+### Example
+```
+let s = "hello, world!";
+if s.starts_with("hello, ") {
+    assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
+}
+```
+Use instead:
+```
+let s = "hello, world!";
+if let Some(end) = s.strip_prefix("hello, ") {
+    assert_eq!(end.to_uppercase(), "WORLD!");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_swap.txt b/src/tools/clippy/src/docs/manual_swap.txt
new file mode 100644
index 000000000000..bd9526288e35
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_swap.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for manual swapping.
+
+### Why is this bad?
+The `std::mem::swap` function exposes the intent better
+without deinitializing or copying either variable.
+
+### Example
+```
+let mut a = 42;
+let mut b = 1337;
+
+let t = b;
+b = a;
+a = t;
+```
+Use std::mem::swap():
+```
+let mut a = 1;
+let mut b = 2;
+std::mem::swap(&mut a, &mut b);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/manual_unwrap_or.txt b/src/tools/clippy/src/docs/manual_unwrap_or.txt
new file mode 100644
index 000000000000..1fd7d831bfca
--- /dev/null
+++ b/src/tools/clippy/src/docs/manual_unwrap_or.txt
@@ -0,0 +1,20 @@
+### What it does
+Finds patterns that reimplement `Option::unwrap_or` or `Result::unwrap_or`.
+
+### Why is this bad?
+Concise code helps focusing on behavior instead of boilerplate.
+
+### Example
+```
+let foo: Option<i32> = None;
+match foo {
+    Some(v) => v,
+    None => 1,
+};
+```
+
+Use instead:
+```
+let foo: Option<i32> = None;
+foo.unwrap_or(1);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/many_single_char_names.txt b/src/tools/clippy/src/docs/many_single_char_names.txt
new file mode 100644
index 000000000000..55ee5da55574
--- /dev/null
+++ b/src/tools/clippy/src/docs/many_single_char_names.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for too many variables whose name consists of a
+single character.
+
+### Why is this bad?
+It's hard to memorize what a variable means without a
+descriptive name.
+
+### Example
+```
+let (a, b, c, d, e, f, g) = (...);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_clone.txt b/src/tools/clippy/src/docs/map_clone.txt
new file mode 100644
index 000000000000..3ee27f072ef3
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_clone.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usage of `map(|x| x.clone())` or
+dereferencing closures for `Copy` types, on `Iterator` or `Option`,
+and suggests `cloned()` or `copied()` instead
+
+### Why is this bad?
+Readability, this can be written more concisely
+
+### Example
+```
+let x = vec![42, 43];
+let y = x.iter();
+let z = y.map(|i| *i);
+```
+
+The correct use would be:
+
+```
+let x = vec![42, 43];
+let y = x.iter();
+let z = y.cloned();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_collect_result_unit.txt b/src/tools/clippy/src/docs/map_collect_result_unit.txt
new file mode 100644
index 000000000000..9b720612495c
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_collect_result_unit.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for usage of `_.map(_).collect::<Result<(), _>()`.
+
+### Why is this bad?
+Using `try_for_each` instead is more readable and idiomatic.
+
+### Example
+```
+(0..3).map(|t| Err(t)).collect::<Result<(), _>>();
+```
+Use instead:
+```
+(0..3).try_for_each(|t| Err(t));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_entry.txt b/src/tools/clippy/src/docs/map_entry.txt
new file mode 100644
index 000000000000..20dba1798d0d
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_entry.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for uses of `contains_key` + `insert` on `HashMap`
+or `BTreeMap`.
+
+### Why is this bad?
+Using `entry` is more efficient.
+
+### Known problems
+The suggestion may have type inference errors in some cases. e.g.
+```
+let mut map = std::collections::HashMap::new();
+let _ = if !map.contains_key(&0) {
+    map.insert(0, 0)
+} else {
+    None
+};
+```
+
+### Example
+```
+if !map.contains_key(&k) {
+    map.insert(k, v);
+}
+```
+Use instead:
+```
+map.entry(k).or_insert(v);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_err_ignore.txt b/src/tools/clippy/src/docs/map_err_ignore.txt
new file mode 100644
index 000000000000..2606c13a7afd
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_err_ignore.txt
@@ -0,0 +1,93 @@
+### What it does
+Checks for instances of `map_err(|_| Some::Enum)`
+
+### Why is this bad?
+This `map_err` throws away the original error rather than allowing the enum to contain and report the cause of the error
+
+### Example
+Before:
+```
+use std::fmt;
+
+#[derive(Debug)]
+enum Error {
+    Indivisible,
+    Remainder(u8),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Error::Indivisible => write!(f, "could not divide input by three"),
+            Error::Remainder(remainder) => write!(
+                f,
+                "input is not divisible by three, remainder = {}",
+                remainder
+            ),
+        }
+    }
+}
+
+impl std::error::Error for Error {}
+
+fn divisible_by_3(input: &str) -> Result<(), Error> {
+    input
+        .parse::<i32>()
+        .map_err(|_| Error::Indivisible)
+        .map(|v| v % 3)
+        .and_then(|remainder| {
+            if remainder == 0 {
+                Ok(())
+            } else {
+                Err(Error::Remainder(remainder as u8))
+            }
+        })
+}
+ ```
+
+ After:
+ ```rust
+use std::{fmt, num::ParseIntError};
+
+#[derive(Debug)]
+enum Error {
+    Indivisible(ParseIntError),
+    Remainder(u8),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Error::Indivisible(_) => write!(f, "could not divide input by three"),
+            Error::Remainder(remainder) => write!(
+                f,
+                "input is not divisible by three, remainder = {}",
+                remainder
+            ),
+        }
+    }
+}
+
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            Error::Indivisible(source) => Some(source),
+            _ => None,
+        }
+    }
+}
+
+fn divisible_by_3(input: &str) -> Result<(), Error> {
+    input
+        .parse::<i32>()
+        .map_err(Error::Indivisible)
+        .map(|v| v % 3)
+        .and_then(|remainder| {
+            if remainder == 0 {
+                Ok(())
+            } else {
+                Err(Error::Remainder(remainder as u8))
+            }
+        })
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_flatten.txt b/src/tools/clippy/src/docs/map_flatten.txt
new file mode 100644
index 000000000000..73c0e51407f2
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_flatten.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for usage of `_.map(_).flatten(_)` on `Iterator` and `Option`
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.flat_map(_)` for `Iterator` or `_.and_then(_)` for `Option`
+
+### Example
+```
+let vec = vec![vec![1]];
+let opt = Some(5);
+
+vec.iter().map(|x| x.iter()).flatten();
+opt.map(|x| Some(x * 2)).flatten();
+```
+
+Use instead:
+```
+vec.iter().flat_map(|x| x.iter());
+opt.and_then(|x| Some(x * 2));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_identity.txt b/src/tools/clippy/src/docs/map_identity.txt
new file mode 100644
index 000000000000..e2e7af0bed9b
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_identity.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for instances of `map(f)` where `f` is the identity function.
+
+### Why is this bad?
+It can be written more concisely without the call to `map`.
+
+### Example
+```
+let x = [1, 2, 3];
+let y: Vec<_> = x.iter().map(|x| x).map(|x| 2*x).collect();
+```
+Use instead:
+```
+let x = [1, 2, 3];
+let y: Vec<_> = x.iter().map(|x| 2*x).collect();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/map_unwrap_or.txt b/src/tools/clippy/src/docs/map_unwrap_or.txt
new file mode 100644
index 000000000000..485b29f01b10
--- /dev/null
+++ b/src/tools/clippy/src/docs/map_unwrap_or.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usage of `option.map(_).unwrap_or(_)` or `option.map(_).unwrap_or_else(_)` or
+`result.map(_).unwrap_or_else(_)`.
+
+### Why is this bad?
+Readability, these can be written more concisely (resp.) as
+`option.map_or(_, _)`, `option.map_or_else(_, _)` and `result.map_or_else(_, _)`.
+
+### Known problems
+The order of the arguments is not in execution order
+
+### Examples
+```
+option.map(|a| a + 1).unwrap_or(0);
+result.map(|a| a + 1).unwrap_or_else(some_function);
+```
+
+Use instead:
+```
+option.map_or(0, |a| a + 1);
+result.map_or_else(some_function, |a| a + 1);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_as_ref.txt b/src/tools/clippy/src/docs/match_as_ref.txt
new file mode 100644
index 000000000000..5e5f3d645a4e
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_as_ref.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for match which is used to add a reference to an
+`Option` value.
+
+### Why is this bad?
+Using `as_ref()` or `as_mut()` instead is shorter.
+
+### Example
+```
+let x: Option<()> = None;
+
+let r: Option<&()> = match x {
+    None => None,
+    Some(ref v) => Some(v),
+};
+```
+
+Use instead:
+```
+let x: Option<()> = None;
+
+let r: Option<&()> = x.as_ref();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_bool.txt b/src/tools/clippy/src/docs/match_bool.txt
new file mode 100644
index 000000000000..96f9e1f8b7d1
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_bool.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for matches where match expression is a `bool`. It
+suggests to replace the expression with an `if...else` block.
+
+### Why is this bad?
+It makes the code less readable.
+
+### Example
+```
+let condition: bool = true;
+match condition {
+    true => foo(),
+    false => bar(),
+}
+```
+Use if/else instead:
+```
+let condition: bool = true;
+if condition {
+    foo();
+} else {
+    bar();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_like_matches_macro.txt b/src/tools/clippy/src/docs/match_like_matches_macro.txt
new file mode 100644
index 000000000000..643e2ddc97ba
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_like_matches_macro.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for `match`  or `if let` expressions producing a
+`bool` that could be written using `matches!`
+
+### Why is this bad?
+Readability and needless complexity.
+
+### Known problems
+This lint falsely triggers, if there are arms with
+`cfg` attributes that remove an arm evaluating to `false`.
+
+### Example
+```
+let x = Some(5);
+
+let a = match x {
+    Some(0) => true,
+    _ => false,
+};
+
+let a = if let Some(0) = x {
+    true
+} else {
+    false
+};
+```
+
+Use instead:
+```
+let x = Some(5);
+let a = matches!(x, Some(0));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_on_vec_items.txt b/src/tools/clippy/src/docs/match_on_vec_items.txt
new file mode 100644
index 000000000000..981d18d0f9ed
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_on_vec_items.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for `match vec[idx]` or `match vec[n..m]`.
+
+### Why is this bad?
+This can panic at runtime.
+
+### Example
+```
+let arr = vec![0, 1, 2, 3];
+let idx = 1;
+
+match arr[idx] {
+    0 => println!("{}", 0),
+    1 => println!("{}", 3),
+    _ => {},
+}
+```
+
+Use instead:
+```
+let arr = vec![0, 1, 2, 3];
+let idx = 1;
+
+match arr.get(idx) {
+    Some(0) => println!("{}", 0),
+    Some(1) => println!("{}", 3),
+    _ => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_overlapping_arm.txt b/src/tools/clippy/src/docs/match_overlapping_arm.txt
new file mode 100644
index 000000000000..841c091bd5ca
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_overlapping_arm.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for overlapping match arms.
+
+### Why is this bad?
+It is likely to be an error and if not, makes the code
+less obvious.
+
+### Example
+```
+let x = 5;
+match x {
+    1..=10 => println!("1 ... 10"),
+    5..=15 => println!("5 ... 15"),
+    _ => (),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_ref_pats.txt b/src/tools/clippy/src/docs/match_ref_pats.txt
new file mode 100644
index 000000000000..b1d902995097
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_ref_pats.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for matches where all arms match a reference,
+suggesting to remove the reference and deref the matched expression
+instead. It also checks for `if let &foo = bar` blocks.
+
+### Why is this bad?
+It just makes the code less readable. That reference
+destructuring adds nothing to the code.
+
+### Example
+```
+match x {
+    &A(ref y) => foo(y),
+    &B => bar(),
+    _ => frob(&x),
+}
+```
+
+Use instead:
+```
+match *x {
+    A(ref y) => foo(y),
+    B => bar(),
+    _ => frob(x),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_result_ok.txt b/src/tools/clippy/src/docs/match_result_ok.txt
new file mode 100644
index 000000000000..eea7c8e00f1b
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_result_ok.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for unnecessary `ok()` in `while let`.
+
+### Why is this bad?
+Calling `ok()` in `while let` is unnecessary, instead match
+on `Ok(pat)`
+
+### Example
+```
+while let Some(value) = iter.next().ok() {
+    vec.push(value)
+}
+
+if let Some(value) = iter.next().ok() {
+    vec.push(value)
+}
+```
+Use instead:
+```
+while let Ok(value) = iter.next() {
+    vec.push(value)
+}
+
+if let Ok(value) = iter.next() {
+       vec.push(value)
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_same_arms.txt b/src/tools/clippy/src/docs/match_same_arms.txt
new file mode 100644
index 000000000000..14edf12032e0
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_same_arms.txt
@@ -0,0 +1,38 @@
+### What it does
+Checks for `match` with identical arm bodies.
+
+### Why is this bad?
+This is probably a copy & paste error. If arm bodies
+are the same on purpose, you can factor them
+[using `|`](https://doc.rust-lang.org/book/patterns.html#multiple-patterns).
+
+### Known problems
+False positive possible with order dependent `match`
+(see issue
+[#860](https://github.com/rust-lang/rust-clippy/issues/860)).
+
+### Example
+```
+match foo {
+    Bar => bar(),
+    Quz => quz(),
+    Baz => bar(), // <= oops
+}
+```
+
+This should probably be
+```
+match foo {
+    Bar => bar(),
+    Quz => quz(),
+    Baz => baz(), // <= fixed
+}
+```
+
+or if the original code was not a typo:
+```
+match foo {
+    Bar | Baz => bar(), // <= shows the intent better
+    Quz => quz(),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_single_binding.txt b/src/tools/clippy/src/docs/match_single_binding.txt
new file mode 100644
index 000000000000..67ded0bbd553
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_single_binding.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for useless match that binds to only one value.
+
+### Why is this bad?
+Readability and needless complexity.
+
+### Known problems
+ Suggested replacements may be incorrect when `match`
+is actually binding temporary value, bringing a 'dropped while borrowed' error.
+
+### Example
+```
+match (a, b) {
+    (c, d) => {
+        // useless match
+    }
+}
+```
+
+Use instead:
+```
+let (c, d) = (a, b);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_str_case_mismatch.txt b/src/tools/clippy/src/docs/match_str_case_mismatch.txt
new file mode 100644
index 000000000000..19e74c2084ea
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_str_case_mismatch.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for `match` expressions modifying the case of a string with non-compliant arms
+
+### Why is this bad?
+The arm is unreachable, which is likely a mistake
+
+### Example
+```
+match &*text.to_ascii_lowercase() {
+    "foo" => {},
+    "Bar" => {},
+    _ => {},
+}
+```
+Use instead:
+```
+match &*text.to_ascii_lowercase() {
+    "foo" => {},
+    "bar" => {},
+    _ => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_wild_err_arm.txt b/src/tools/clippy/src/docs/match_wild_err_arm.txt
new file mode 100644
index 000000000000..f89b3a23a1ca
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_wild_err_arm.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for arm which matches all errors with `Err(_)`
+and take drastic actions like `panic!`.
+
+### Why is this bad?
+It is generally a bad practice, similar to
+catching all exceptions in java with `catch(Exception)`
+
+### Example
+```
+let x: Result<i32, &str> = Ok(3);
+match x {
+    Ok(_) => println!("ok"),
+    Err(_) => panic!("err"),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/match_wildcard_for_single_variants.txt b/src/tools/clippy/src/docs/match_wildcard_for_single_variants.txt
new file mode 100644
index 000000000000..25559b9ecdcf
--- /dev/null
+++ b/src/tools/clippy/src/docs/match_wildcard_for_single_variants.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for wildcard enum matches for a single variant.
+
+### Why is this bad?
+New enum variants added by library updates can be missed.
+
+### Known problems
+Suggested replacements may not use correct path to enum
+if it's not present in the current scope.
+
+### Example
+```
+match x {
+    Foo::A => {},
+    Foo::B => {},
+    _ => {},
+}
+```
+
+Use instead:
+```
+match x {
+    Foo::A => {},
+    Foo::B => {},
+    Foo::C => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/maybe_infinite_iter.txt b/src/tools/clippy/src/docs/maybe_infinite_iter.txt
new file mode 100644
index 000000000000..1204a49b4668
--- /dev/null
+++ b/src/tools/clippy/src/docs/maybe_infinite_iter.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for iteration that may be infinite.
+
+### Why is this bad?
+While there may be places where this is acceptable
+(e.g., in event streams), in most cases this is simply an error.
+
+### Known problems
+The code may have a condition to stop iteration, but
+this lint is not clever enough to analyze it.
+
+### Example
+```
+let infinite_iter = 0..;
+[0..].iter().zip(infinite_iter.take_while(|x| *x > 5));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mem_forget.txt b/src/tools/clippy/src/docs/mem_forget.txt
new file mode 100644
index 000000000000..a6888c48fc33
--- /dev/null
+++ b/src/tools/clippy/src/docs/mem_forget.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for usage of `std::mem::forget(t)` where `t` is
+`Drop`.
+
+### Why is this bad?
+`std::mem::forget(t)` prevents `t` from running its
+destructor, possibly causing leaks.
+
+### Example
+```
+mem::forget(Rc::new(55))
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mem_replace_option_with_none.txt b/src/tools/clippy/src/docs/mem_replace_option_with_none.txt
new file mode 100644
index 000000000000..7f243d1c1656
--- /dev/null
+++ b/src/tools/clippy/src/docs/mem_replace_option_with_none.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for `mem::replace()` on an `Option` with
+`None`.
+
+### Why is this bad?
+`Option` already has the method `take()` for
+taking its current value (Some(..) or None) and replacing it with
+`None`.
+
+### Example
+```
+use std::mem;
+
+let mut an_option = Some(0);
+let replaced = mem::replace(&mut an_option, None);
+```
+Is better expressed with:
+```
+let mut an_option = Some(0);
+let taken = an_option.take();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mem_replace_with_default.txt b/src/tools/clippy/src/docs/mem_replace_with_default.txt
new file mode 100644
index 000000000000..24e0913a30c9
--- /dev/null
+++ b/src/tools/clippy/src/docs/mem_replace_with_default.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for `std::mem::replace` on a value of type
+`T` with `T::default()`.
+
+### Why is this bad?
+`std::mem` module already has the method `take` to
+take the current value and replace it with the default value of that type.
+
+### Example
+```
+let mut text = String::from("foo");
+let replaced = std::mem::replace(&mut text, String::default());
+```
+Is better expressed with:
+```
+let mut text = String::from("foo");
+let taken = std::mem::take(&mut text);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mem_replace_with_uninit.txt b/src/tools/clippy/src/docs/mem_replace_with_uninit.txt
new file mode 100644
index 000000000000..0bb483668abc
--- /dev/null
+++ b/src/tools/clippy/src/docs/mem_replace_with_uninit.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for `mem::replace(&mut _, mem::uninitialized())`
+and `mem::replace(&mut _, mem::zeroed())`.
+
+### Why is this bad?
+This will lead to undefined behavior even if the
+value is overwritten later, because the uninitialized value may be
+observed in the case of a panic.
+
+### Example
+```
+use std::mem;
+
+#[allow(deprecated, invalid_value)]
+fn myfunc (v: &mut Vec<i32>) {
+    let taken_v = unsafe { mem::replace(v, mem::uninitialized()) };
+    let new_v = may_panic(taken_v); // undefined behavior on panic
+    mem::forget(mem::replace(v, new_v));
+}
+```
+
+The [take_mut](https://docs.rs/take_mut) crate offers a sound solution,
+at the cost of either lazily creating a replacement value or aborting
+on panic, to ensure that the uninitialized value cannot be observed.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/min_max.txt b/src/tools/clippy/src/docs/min_max.txt
new file mode 100644
index 000000000000..6acf0f932e98
--- /dev/null
+++ b/src/tools/clippy/src/docs/min_max.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for expressions where `std::cmp::min` and `max` are
+used to clamp values, but switched so that the result is constant.
+
+### Why is this bad?
+This is in all probability not the intended outcome. At
+the least it hurts readability of the code.
+
+### Example
+```
+min(0, max(100, x))
+
+// or
+
+x.max(100).min(0)
+```
+It will always be equal to `0`. Probably the author meant to clamp the value
+between 0 and 100, but has erroneously swapped `min` and `max`.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mismatched_target_os.txt b/src/tools/clippy/src/docs/mismatched_target_os.txt
new file mode 100644
index 000000000000..51e5ec6e7c5c
--- /dev/null
+++ b/src/tools/clippy/src/docs/mismatched_target_os.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for cfg attributes having operating systems used in target family position.
+
+### Why is this bad?
+The configuration option will not be recognised and the related item will not be included
+by the conditional compilation engine.
+
+### Example
+```
+#[cfg(linux)]
+fn conditional() { }
+```
+
+Use instead:
+```
+#[cfg(target_os = "linux")]
+fn conditional() { }
+
+// or
+
+#[cfg(unix)]
+fn conditional() { }
+```
+Check the [Rust Reference](https://doc.rust-lang.org/reference/conditional-compilation.html#target_os) for more details.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mismatching_type_param_order.txt b/src/tools/clippy/src/docs/mismatching_type_param_order.txt
new file mode 100644
index 000000000000..ffc7f32d0aad
--- /dev/null
+++ b/src/tools/clippy/src/docs/mismatching_type_param_order.txt
@@ -0,0 +1,33 @@
+### What it does
+Checks for type parameters which are positioned inconsistently between
+a type definition and impl block. Specifically, a parameter in an impl
+block which has the same name as a parameter in the type def, but is in
+a different place.
+
+### Why is this bad?
+Type parameters are determined by their position rather than name.
+Naming type parameters inconsistently may cause you to refer to the
+wrong type parameter.
+
+### Limitations
+This lint only applies to impl blocks with simple generic params, e.g.
+`A`. If there is anything more complicated, such as a tuple, it will be
+ignored.
+
+### Example
+```
+struct Foo<A, B> {
+    x: A,
+    y: B,
+}
+// inside the impl, B refers to Foo::A
+impl<B, A> Foo<B, A> {}
+```
+Use instead:
+```
+struct Foo<A, B> {
+    x: A,
+    y: B,
+}
+impl<A, B> Foo<A, B> {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/misrefactored_assign_op.txt b/src/tools/clippy/src/docs/misrefactored_assign_op.txt
new file mode 100644
index 000000000000..3d691fe4178b
--- /dev/null
+++ b/src/tools/clippy/src/docs/misrefactored_assign_op.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for `a op= a op b` or `a op= b op a` patterns.
+
+### Why is this bad?
+Most likely these are bugs where one meant to write `a
+op= b`.
+
+### Known problems
+Clippy cannot know for sure if `a op= a op b` should have
+been `a = a op a op b` or `a = a op b`/`a op= b`. Therefore, it suggests both.
+If `a op= a op b` is really the correct behavior it should be
+written as `a = a op a op b` as it's less confusing.
+
+### Example
+```
+let mut a = 5;
+let b = 2;
+// ...
+a += a + b;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_const_for_fn.txt b/src/tools/clippy/src/docs/missing_const_for_fn.txt
new file mode 100644
index 000000000000..067614d4c46b
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_const_for_fn.txt
@@ -0,0 +1,40 @@
+### What it does
+Suggests the use of `const` in functions and methods where possible.
+
+### Why is this bad?
+Not having the function const prevents callers of the function from being const as well.
+
+### Known problems
+Const functions are currently still being worked on, with some features only being available
+on nightly. This lint does not consider all edge cases currently and the suggestions may be
+incorrect if you are using this lint on stable.
+
+Also, the lint only runs one pass over the code. Consider these two non-const functions:
+
+```
+fn a() -> i32 {
+    0
+}
+fn b() -> i32 {
+    a()
+}
+```
+
+When running Clippy, the lint will only suggest to make `a` const, because `b` at this time
+can't be const as it calls a non-const function. Making `a` const and running Clippy again,
+will suggest to make `b` const, too.
+
+### Example
+```
+fn new() -> Self {
+    Self { random_number: 42 }
+}
+```
+
+Could be a const fn:
+
+```
+const fn new() -> Self {
+    Self { random_number: 42 }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_docs_in_private_items.txt b/src/tools/clippy/src/docs/missing_docs_in_private_items.txt
new file mode 100644
index 000000000000..5d37505bb171
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_docs_in_private_items.txt
@@ -0,0 +1,9 @@
+### What it does
+Warns if there is missing doc for any documentable item
+(public or private).
+
+### Why is this bad?
+Doc is good. *rustc* has a `MISSING_DOCS`
+allowed-by-default lint for
+public members, but has no way to enforce documentation of private items.
+This lint fixes that.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_enforced_import_renames.txt b/src/tools/clippy/src/docs/missing_enforced_import_renames.txt
new file mode 100644
index 000000000000..8f4649bd5923
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_enforced_import_renames.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for imports that do not rename the item as specified
+in the `enforce-import-renames` config option.
+
+### Why is this bad?
+Consistency is important, if a project has defined import
+renames they should be followed. More practically, some item names are too
+vague outside of their defining scope this can enforce a more meaningful naming.
+
+### Example
+An example clippy.toml configuration:
+```
+enforced-import-renames = [ { path = "serde_json::Value", rename = "JsonValue" }]
+```
+
+```
+use serde_json::Value;
+```
+Use instead:
+```
+use serde_json::Value as JsonValue;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_errors_doc.txt b/src/tools/clippy/src/docs/missing_errors_doc.txt
new file mode 100644
index 000000000000..028778d85aeb
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_errors_doc.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks the doc comments of publicly visible functions that
+return a `Result` type and warns if there is no `# Errors` section.
+
+### Why is this bad?
+Documenting the type of errors that can be returned from a
+function can help callers write code to handle the errors appropriately.
+
+### Examples
+Since the following function returns a `Result` it has an `# Errors` section in
+its doc comment:
+
+```
+/// # Errors
+///
+/// Will return `Err` if `filename` does not exist or the user does not have
+/// permission to read it.
+pub fn read(filename: String) -> io::Result<String> {
+    unimplemented!();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_inline_in_public_items.txt b/src/tools/clippy/src/docs/missing_inline_in_public_items.txt
new file mode 100644
index 000000000000..d90c50fe7f9e
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_inline_in_public_items.txt
@@ -0,0 +1,45 @@
+### What it does
+It lints if an exported function, method, trait method with default impl,
+or trait method impl is not `#[inline]`.
+
+### Why is this bad?
+In general, it is not. Functions can be inlined across
+crates when that's profitable as long as any form of LTO is used. When LTO is disabled,
+functions that are not `#[inline]` cannot be inlined across crates. Certain types of crates
+might intend for most of the methods in their public API to be able to be inlined across
+crates even when LTO is disabled. For these types of crates, enabling this lint might make
+sense. It allows the crate to require all exported methods to be `#[inline]` by default, and
+then opt out for specific methods where this might not make sense.
+
+### Example
+```
+pub fn foo() {} // missing #[inline]
+fn ok() {} // ok
+#[inline] pub fn bar() {} // ok
+#[inline(always)] pub fn baz() {} // ok
+
+pub trait Bar {
+  fn bar(); // ok
+  fn def_bar() {} // missing #[inline]
+}
+
+struct Baz;
+impl Baz {
+   fn private() {} // ok
+}
+
+impl Bar for Baz {
+  fn bar() {} // ok - Baz is not exported
+}
+
+pub struct PubBaz;
+impl PubBaz {
+   fn private() {} // ok
+   pub fn not_private() {} // missing #[inline]
+}
+
+impl Bar for PubBaz {
+   fn bar() {} // missing #[inline]
+   fn def_bar() {} // missing #[inline]
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_panics_doc.txt b/src/tools/clippy/src/docs/missing_panics_doc.txt
new file mode 100644
index 000000000000..e5e39a824519
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_panics_doc.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks the doc comments of publicly visible functions that
+may panic and warns if there is no `# Panics` section.
+
+### Why is this bad?
+Documenting the scenarios in which panicking occurs
+can help callers who do not want to panic to avoid those situations.
+
+### Examples
+Since the following function may panic it has a `# Panics` section in
+its doc comment:
+
+```
+/// # Panics
+///
+/// Will panic if y is 0
+pub fn divide_by(x: i32, y: i32) -> i32 {
+    if y == 0 {
+        panic!("Cannot divide by 0")
+    } else {
+        x / y
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_safety_doc.txt b/src/tools/clippy/src/docs/missing_safety_doc.txt
new file mode 100644
index 000000000000..6492eb84f63b
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_safety_doc.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for the doc comments of publicly visible
+unsafe functions and warns if there is no `# Safety` section.
+
+### Why is this bad?
+Unsafe functions should document their safety
+preconditions, so that users can be sure they are using them safely.
+
+### Examples
+```
+/// This function should really be documented
+pub unsafe fn start_apocalypse(u: &mut Universe) {
+    unimplemented!();
+}
+```
+
+At least write a line about safety:
+
+```
+/// # Safety
+///
+/// This function should not be called before the horsemen are ready.
+pub unsafe fn start_apocalypse(u: &mut Universe) {
+    unimplemented!();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/missing_spin_loop.txt b/src/tools/clippy/src/docs/missing_spin_loop.txt
new file mode 100644
index 000000000000..3a06a91d7183
--- /dev/null
+++ b/src/tools/clippy/src/docs/missing_spin_loop.txt
@@ -0,0 +1,27 @@
+### What it does
+Check for empty spin loops
+
+### Why is this bad?
+The loop body should have something like `thread::park()` or at least
+`std::hint::spin_loop()` to avoid needlessly burning cycles and conserve
+energy. Perhaps even better use an actual lock, if possible.
+
+### Known problems
+This lint doesn't currently trigger on `while let` or
+`loop { match .. { .. } }` loops, which would be considered idiomatic in
+combination with e.g. `AtomicBool::compare_exchange_weak`.
+
+### Example
+
+```
+use core::sync::atomic::{AtomicBool, Ordering};
+let b = AtomicBool::new(true);
+// give a ref to `b` to another thread,wait for it to become false
+while b.load(Ordering::Acquire) {};
+```
+Use instead:
+```
+while b.load(Ordering::Acquire) {
+    std::hint::spin_loop()
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mistyped_literal_suffixes.txt b/src/tools/clippy/src/docs/mistyped_literal_suffixes.txt
new file mode 100644
index 000000000000..1760fcbfeacc
--- /dev/null
+++ b/src/tools/clippy/src/docs/mistyped_literal_suffixes.txt
@@ -0,0 +1,15 @@
+### What it does
+Warns for mistyped suffix in literals
+
+### Why is this bad?
+This is most probably a typo
+
+### Known problems
+- Does not match on integers too large to fit in the corresponding unsigned type
+- Does not match on `_127` since that is a valid grouping for decimal and octal numbers
+
+### Example
+```
+`2_32` => `2_i32`
+`250_8 => `250_u8`
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mixed_case_hex_literals.txt b/src/tools/clippy/src/docs/mixed_case_hex_literals.txt
new file mode 100644
index 000000000000..d2d01e0c98eb
--- /dev/null
+++ b/src/tools/clippy/src/docs/mixed_case_hex_literals.txt
@@ -0,0 +1,16 @@
+### What it does
+Warns on hexadecimal literals with mixed-case letter
+digits.
+
+### Why is this bad?
+It looks confusing.
+
+### Example
+```
+0x1a9BAcD
+```
+
+Use instead:
+```
+0x1A9BACD
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mixed_read_write_in_expression.txt b/src/tools/clippy/src/docs/mixed_read_write_in_expression.txt
new file mode 100644
index 000000000000..02d1c5d05252
--- /dev/null
+++ b/src/tools/clippy/src/docs/mixed_read_write_in_expression.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for a read and a write to the same variable where
+whether the read occurs before or after the write depends on the evaluation
+order of sub-expressions.
+
+### Why is this bad?
+It is often confusing to read. As described [here](https://doc.rust-lang.org/reference/expressions.html?highlight=subexpression#evaluation-order-of-operands),
+the operands of these expressions are evaluated before applying the effects of the expression.
+
+### Known problems
+Code which intentionally depends on the evaluation
+order, or which is correct for any evaluation order.
+
+### Example
+```
+let mut x = 0;
+
+let a = {
+    x = 1;
+    1
+} + x;
+// Unclear whether a is 1 or 2.
+```
+
+Use instead:
+```
+let tmp = {
+    x = 1;
+    1
+};
+let a = tmp + x;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mod_module_files.txt b/src/tools/clippy/src/docs/mod_module_files.txt
new file mode 100644
index 000000000000..95bca583afd3
--- /dev/null
+++ b/src/tools/clippy/src/docs/mod_module_files.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks that module layout uses only self named module files, bans `mod.rs` files.
+
+### Why is this bad?
+Having multiple module layout styles in a project can be confusing.
+
+### Example
+```
+src/
+  stuff/
+    stuff_files.rs
+    mod.rs
+  lib.rs
+```
+Use instead:
+```
+src/
+  stuff/
+    stuff_files.rs
+  stuff.rs
+  lib.rs
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/module_inception.txt b/src/tools/clippy/src/docs/module_inception.txt
new file mode 100644
index 000000000000..d80a1b8d8fe5
--- /dev/null
+++ b/src/tools/clippy/src/docs/module_inception.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for modules that have the same name as their
+parent module
+
+### Why is this bad?
+A typical beginner mistake is to have `mod foo;` and
+again `mod foo { ..
+}` in `foo.rs`.
+The expectation is that items inside the inner `mod foo { .. }` are then
+available
+through `foo::x`, but they are only available through
+`foo::foo::x`.
+If this is done on purpose, it would be better to choose a more
+representative module name.
+
+### Example
+```
+// lib.rs
+mod foo;
+// foo.rs
+mod foo {
+    ...
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/module_name_repetitions.txt b/src/tools/clippy/src/docs/module_name_repetitions.txt
new file mode 100644
index 000000000000..3bc05d02780c
--- /dev/null
+++ b/src/tools/clippy/src/docs/module_name_repetitions.txt
@@ -0,0 +1,20 @@
+### What it does
+Detects type names that are prefixed or suffixed by the
+containing module's name.
+
+### Why is this bad?
+It requires the user to type the module name twice.
+
+### Example
+```
+mod cake {
+    struct BlackForestCake;
+}
+```
+
+Use instead:
+```
+mod cake {
+    struct BlackForest;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/modulo_arithmetic.txt b/src/tools/clippy/src/docs/modulo_arithmetic.txt
new file mode 100644
index 000000000000..ff7296f3c5b8
--- /dev/null
+++ b/src/tools/clippy/src/docs/modulo_arithmetic.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for modulo arithmetic.
+
+### Why is this bad?
+The results of modulo (%) operation might differ
+depending on the language, when negative numbers are involved.
+If you interop with different languages it might be beneficial
+to double check all places that use modulo arithmetic.
+
+For example, in Rust `17 % -3 = 2`, but in Python `17 % -3 = -1`.
+
+### Example
+```
+let x = -17 % 3;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/modulo_one.txt b/src/tools/clippy/src/docs/modulo_one.txt
new file mode 100644
index 000000000000..bc8f95b0be69
--- /dev/null
+++ b/src/tools/clippy/src/docs/modulo_one.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for getting the remainder of a division by one or minus
+one.
+
+### Why is this bad?
+The result for a divisor of one can only ever be zero; for
+minus one it can cause panic/overflow (if the left operand is the minimal value of
+the respective integer type) or results in zero. No one will write such code
+deliberately, unless trying to win an Underhanded Rust Contest. Even for that
+contest, it's probably a bad idea. Use something more underhanded.
+
+### Example
+```
+let a = x % 1;
+let a = x % -1;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/multi_assignments.txt b/src/tools/clippy/src/docs/multi_assignments.txt
new file mode 100644
index 000000000000..ed1f1b420cbd
--- /dev/null
+++ b/src/tools/clippy/src/docs/multi_assignments.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for nested assignments.
+
+### Why is this bad?
+While this is in most cases already a type mismatch,
+the result of an assignment being `()` can throw off people coming from languages like python or C,
+where such assignments return a copy of the assigned value.
+
+### Example
+```
+a = b = 42;
+```
+Use instead:
+```
+b = 42;
+a = b;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/multiple_crate_versions.txt b/src/tools/clippy/src/docs/multiple_crate_versions.txt
new file mode 100644
index 000000000000..cf2d2c6abee3
--- /dev/null
+++ b/src/tools/clippy/src/docs/multiple_crate_versions.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks to see if multiple versions of a crate are being
+used.
+
+### Why is this bad?
+This bloats the size of targets, and can lead to
+confusing error messages when structs or traits are used interchangeably
+between different versions of a crate.
+
+### Known problems
+Because this can be caused purely by the dependencies
+themselves, it's not always possible to fix this issue.
+
+### Example
+```
+[dependencies]
+ctrlc = "=3.1.0"
+ansi_term = "=0.11.0"
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/multiple_inherent_impl.txt b/src/tools/clippy/src/docs/multiple_inherent_impl.txt
new file mode 100644
index 000000000000..9d42286560ce
--- /dev/null
+++ b/src/tools/clippy/src/docs/multiple_inherent_impl.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for multiple inherent implementations of a struct
+
+### Why is this bad?
+Splitting the implementation of a type makes the code harder to navigate.
+
+### Example
+```
+struct X;
+impl X {
+    fn one() {}
+}
+impl X {
+    fn other() {}
+}
+```
+
+Could be written:
+
+```
+struct X;
+impl X {
+    fn one() {}
+    fn other() {}
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/must_use_candidate.txt b/src/tools/clippy/src/docs/must_use_candidate.txt
new file mode 100644
index 000000000000..70890346fe6b
--- /dev/null
+++ b/src/tools/clippy/src/docs/must_use_candidate.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for public functions that have no
+`#[must_use]` attribute, but return something not already marked
+must-use, have no mutable arg and mutate no statics.
+
+### Why is this bad?
+Not bad at all, this lint just shows places where
+you could add the attribute.
+
+### Known problems
+The lint only checks the arguments for mutable
+types without looking if they are actually changed. On the other hand,
+it also ignores a broad range of potentially interesting side effects,
+because we cannot decide whether the programmer intends the function to
+be called for the side effect or the result. Expect many false
+positives. At least we don't lint if the result type is unit or already
+`#[must_use]`.
+
+### Examples
+```
+// this could be annotated with `#[must_use]`.
+fn id<T>(t: T) -> T { t }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/must_use_unit.txt b/src/tools/clippy/src/docs/must_use_unit.txt
new file mode 100644
index 000000000000..cabbb23f8651
--- /dev/null
+++ b/src/tools/clippy/src/docs/must_use_unit.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for a `#[must_use]` attribute on
+unit-returning functions and methods.
+
+### Why is this bad?
+Unit values are useless. The attribute is likely
+a remnant of a refactoring that removed the return type.
+
+### Examples
+```
+#[must_use]
+fn useless() { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mut_from_ref.txt b/src/tools/clippy/src/docs/mut_from_ref.txt
new file mode 100644
index 000000000000..cc1da12549a5
--- /dev/null
+++ b/src/tools/clippy/src/docs/mut_from_ref.txt
@@ -0,0 +1,26 @@
+### What it does
+This lint checks for functions that take immutable references and return
+mutable ones. This will not trigger if no unsafe code exists as there
+are multiple safe functions which will do this transformation
+
+To be on the conservative side, if there's at least one mutable
+reference with the output lifetime, this lint will not trigger.
+
+### Why is this bad?
+Creating a mutable reference which can be repeatably derived from an
+immutable reference is unsound as it allows creating multiple live
+mutable references to the same object.
+
+This [error](https://github.com/rust-lang/rust/issues/39465) actually
+lead to an interim Rust release 1.15.1.
+
+### Known problems
+This pattern is used by memory allocators to allow allocating multiple
+objects while returning mutable references to each one. So long as
+different mutable references are returned each time such a function may
+be safe.
+
+### Example
+```
+fn foo(&Foo) -> &mut Bar { .. }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mut_mut.txt b/src/tools/clippy/src/docs/mut_mut.txt
new file mode 100644
index 000000000000..0bd34dd24b26
--- /dev/null
+++ b/src/tools/clippy/src/docs/mut_mut.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for instances of `mut mut` references.
+
+### Why is this bad?
+Multiple `mut`s don't add anything meaningful to the
+source. This is either a copy'n'paste error, or it shows a fundamental
+misunderstanding of references.
+
+### Example
+```
+let x = &mut &mut y;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mut_mutex_lock.txt b/src/tools/clippy/src/docs/mut_mutex_lock.txt
new file mode 100644
index 000000000000..5e9ad8a3f176
--- /dev/null
+++ b/src/tools/clippy/src/docs/mut_mutex_lock.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for `&mut Mutex::lock` calls
+
+### Why is this bad?
+`Mutex::lock` is less efficient than
+calling `Mutex::get_mut`. In addition you also have a statically
+guarantee that the mutex isn't locked, instead of just a runtime
+guarantee.
+
+### Example
+```
+use std::sync::{Arc, Mutex};
+
+let mut value_rc = Arc::new(Mutex::new(42_u8));
+let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
+
+let mut value = value_mutex.lock().unwrap();
+*value += 1;
+```
+Use instead:
+```
+use std::sync::{Arc, Mutex};
+
+let mut value_rc = Arc::new(Mutex::new(42_u8));
+let value_mutex = Arc::get_mut(&mut value_rc).unwrap();
+
+let value = value_mutex.get_mut().unwrap();
+*value += 1;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mut_range_bound.txt b/src/tools/clippy/src/docs/mut_range_bound.txt
new file mode 100644
index 000000000000..e9c38a543b14
--- /dev/null
+++ b/src/tools/clippy/src/docs/mut_range_bound.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for loops which have a range bound that is a mutable variable
+
+### Why is this bad?
+One might think that modifying the mutable variable changes the loop bounds
+
+### Known problems
+False positive when mutation is followed by a `break`, but the `break` is not immediately
+after the mutation:
+
+```
+let mut x = 5;
+for _ in 0..x {
+    x += 1; // x is a range bound that is mutated
+    ..; // some other expression
+    break; // leaves the loop, so mutation is not an issue
+}
+```
+
+False positive on nested loops ([#6072](https://github.com/rust-lang/rust-clippy/issues/6072))
+
+### Example
+```
+let mut foo = 42;
+for i in 0..foo {
+    foo -= 1;
+    println!("{}", i); // prints numbers from 0 to 42, not 0 to 21
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mutable_key_type.txt b/src/tools/clippy/src/docs/mutable_key_type.txt
new file mode 100644
index 000000000000..15fe34f2bb5e
--- /dev/null
+++ b/src/tools/clippy/src/docs/mutable_key_type.txt
@@ -0,0 +1,61 @@
+### What it does
+Checks for sets/maps with mutable key types.
+
+### Why is this bad?
+All of `HashMap`, `HashSet`, `BTreeMap` and
+`BtreeSet` rely on either the hash or the order of keys be unchanging,
+so having types with interior mutability is a bad idea.
+
+### Known problems
+
+#### False Positives
+It's correct to use a struct that contains interior mutability as a key, when its
+implementation of `Hash` or `Ord` doesn't access any of the interior mutable types.
+However, this lint is unable to recognize this, so it will often cause false positives in
+theses cases.  The `bytes` crate is a great example of this.
+
+#### False Negatives
+For custom `struct`s/`enum`s, this lint is unable to check for interior mutability behind
+indirection.  For example, `struct BadKey<'a>(&'a Cell<usize>)` will be seen as immutable
+and cause a false negative if its implementation of `Hash`/`Ord` accesses the `Cell`.
+
+This lint does check a few cases for indirection.  Firstly, using some standard library
+types (`Option`, `Result`, `Box`, `Rc`, `Arc`, `Vec`, `VecDeque`, `BTreeMap` and
+`BTreeSet`) directly as keys (e.g. in `HashMap<Box<Cell<usize>>, ()>`) **will** trigger the
+lint, because the impls of `Hash`/`Ord` for these types directly call `Hash`/`Ord` on their
+contained type.
+
+Secondly, the implementations of `Hash` and `Ord` for raw pointers (`*const T` or `*mut T`)
+apply only to the **address** of the contained value.  Therefore, interior mutability
+behind raw pointers (e.g. in `HashSet<*mut Cell<usize>>`) can't impact the value of `Hash`
+or `Ord`, and therefore will not trigger this link.  For more info, see issue
+[#6745](https://github.com/rust-lang/rust-clippy/issues/6745).
+
+### Example
+```
+use std::cmp::{PartialEq, Eq};
+use std::collections::HashSet;
+use std::hash::{Hash, Hasher};
+use std::sync::atomic::AtomicUsize;
+
+struct Bad(AtomicUsize);
+impl PartialEq for Bad {
+    fn eq(&self, rhs: &Self) -> bool {
+         ..
+; unimplemented!();
+    }
+}
+
+impl Eq for Bad {}
+
+impl Hash for Bad {
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        ..
+; unimplemented!();
+    }
+}
+
+fn main() {
+    let _: HashSet<Bad> = HashSet::new();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mutex_atomic.txt b/src/tools/clippy/src/docs/mutex_atomic.txt
new file mode 100644
index 000000000000..062ac8b323b7
--- /dev/null
+++ b/src/tools/clippy/src/docs/mutex_atomic.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usages of `Mutex<X>` where an atomic will do.
+
+### Why is this bad?
+Using a mutex just to make access to a plain bool or
+reference sequential is shooting flies with cannons.
+`std::sync::atomic::AtomicBool` and `std::sync::atomic::AtomicPtr` are leaner and
+faster.
+
+### Known problems
+This lint cannot detect if the mutex is actually used
+for waiting before a critical section.
+
+### Example
+```
+let x = Mutex::new(&y);
+```
+
+Use instead:
+```
+let x = AtomicBool::new(y);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/mutex_integer.txt b/src/tools/clippy/src/docs/mutex_integer.txt
new file mode 100644
index 000000000000..f9dbdfb904c9
--- /dev/null
+++ b/src/tools/clippy/src/docs/mutex_integer.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usages of `Mutex<X>` where `X` is an integral
+type.
+
+### Why is this bad?
+Using a mutex just to make access to a plain integer
+sequential is
+shooting flies with cannons. `std::sync::atomic::AtomicUsize` is leaner and faster.
+
+### Known problems
+This lint cannot detect if the mutex is actually used
+for waiting before a critical section.
+
+### Example
+```
+let x = Mutex::new(0usize);
+```
+
+Use instead:
+```
+let x = AtomicUsize::new(0usize);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/naive_bytecount.txt b/src/tools/clippy/src/docs/naive_bytecount.txt
new file mode 100644
index 000000000000..24659dc79ae7
--- /dev/null
+++ b/src/tools/clippy/src/docs/naive_bytecount.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for naive byte counts
+
+### Why is this bad?
+The [`bytecount`](https://crates.io/crates/bytecount)
+crate has methods to count your bytes faster, especially for large slices.
+
+### Known problems
+If you have predominantly small slices, the
+`bytecount::count(..)` method may actually be slower. However, if you can
+ensure that less than 2³²-1 matches arise, the `naive_count_32(..)` can be
+faster in those cases.
+
+### Example
+```
+let count = vec.iter().filter(|x| **x == 0u8).count();
+```
+
+Use instead:
+```
+let count = bytecount::count(&vec, 0u8);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_arbitrary_self_type.txt b/src/tools/clippy/src/docs/needless_arbitrary_self_type.txt
new file mode 100644
index 000000000000..8216a3a3fb6e
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_arbitrary_self_type.txt
@@ -0,0 +1,44 @@
+### What it does
+The lint checks for `self` in fn parameters that
+specify the `Self`-type explicitly
+### Why is this bad?
+Increases the amount and decreases the readability of code
+
+### Example
+```
+enum ValType {
+    I32,
+    I64,
+    F32,
+    F64,
+}
+
+impl ValType {
+    pub fn bytes(self: Self) -> usize {
+        match self {
+            Self::I32 | Self::F32 => 4,
+            Self::I64 | Self::F64 => 8,
+        }
+    }
+}
+```
+
+Could be rewritten as
+
+```
+enum ValType {
+    I32,
+    I64,
+    F32,
+    F64,
+}
+
+impl ValType {
+    pub fn bytes(self) -> usize {
+        match self {
+            Self::I32 | Self::F32 => 4,
+            Self::I64 | Self::F64 => 8,
+        }
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_bitwise_bool.txt b/src/tools/clippy/src/docs/needless_bitwise_bool.txt
new file mode 100644
index 000000000000..fcd7b730aaae
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_bitwise_bool.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for uses of bitwise and/or operators between booleans, where performance may be improved by using
+a lazy and.
+
+### Why is this bad?
+The bitwise operators do not support short-circuiting, so it may hinder code performance.
+Additionally, boolean logic "masked" as bitwise logic is not caught by lints like `unnecessary_fold`
+
+### Known problems
+This lint evaluates only when the right side is determined to have no side effects. At this time, that
+determination is quite conservative.
+
+### Example
+```
+let (x,y) = (true, false);
+if x & !y {} // where both x and y are booleans
+```
+Use instead:
+```
+let (x,y) = (true, false);
+if x && !y {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_bool.txt b/src/tools/clippy/src/docs/needless_bool.txt
new file mode 100644
index 000000000000..b5c78871f14f
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_bool.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for expressions of the form `if c { true } else {
+false }` (or vice versa) and suggests using the condition directly.
+
+### Why is this bad?
+Redundant code.
+
+### Known problems
+Maybe false positives: Sometimes, the two branches are
+painstakingly documented (which we, of course, do not detect), so they *may*
+have some value. Even then, the documentation can be rewritten to match the
+shorter code.
+
+### Example
+```
+if x {
+    false
+} else {
+    true
+}
+```
+
+Use instead:
+```
+!x
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_borrow.txt b/src/tools/clippy/src/docs/needless_borrow.txt
new file mode 100644
index 000000000000..4debcf473723
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_borrow.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for address of operations (`&`) that are going to
+be dereferenced immediately by the compiler.
+
+### Why is this bad?
+Suggests that the receiver of the expression borrows
+the expression.
+
+### Example
+```
+fn fun(_a: &i32) {}
+
+let x: &i32 = &&&&&&5;
+fun(&x);
+```
+
+Use instead:
+```
+let x: &i32 = &5;
+fun(x);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_borrowed_reference.txt b/src/tools/clippy/src/docs/needless_borrowed_reference.txt
new file mode 100644
index 000000000000..55faa0cf5719
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_borrowed_reference.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for bindings that destructure a reference and borrow the inner
+value with `&ref`.
+
+### Why is this bad?
+This pattern has no effect in almost all cases.
+
+### Known problems
+In some cases, `&ref` is needed to avoid a lifetime mismatch error.
+Example:
+```
+fn foo(a: &Option<String>, b: &Option<String>) {
+    match (a, b) {
+        (None, &ref c) | (&ref c, None) => (),
+        (&Some(ref c), _) => (),
+    };
+}
+```
+
+### Example
+```
+let mut v = Vec::<String>::new();
+v.iter_mut().filter(|&ref a| a.is_empty());
+```
+
+Use instead:
+```
+let mut v = Vec::<String>::new();
+v.iter_mut().filter(|a| a.is_empty());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_collect.txt b/src/tools/clippy/src/docs/needless_collect.txt
new file mode 100644
index 000000000000..275c39afc9df
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_collect.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for functions collecting an iterator when collect
+is not needed.
+
+### Why is this bad?
+`collect` causes the allocation of a new data structure,
+when this allocation may not be needed.
+
+### Example
+```
+let len = iterator.clone().collect::<Vec<_>>().len();
+// should be
+let len = iterator.count();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_continue.txt b/src/tools/clippy/src/docs/needless_continue.txt
new file mode 100644
index 000000000000..2cee621c1af0
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_continue.txt
@@ -0,0 +1,61 @@
+### What it does
+The lint checks for `if`-statements appearing in loops
+that contain a `continue` statement in either their main blocks or their
+`else`-blocks, when omitting the `else`-block possibly with some
+rearrangement of code can make the code easier to understand.
+
+### Why is this bad?
+Having explicit `else` blocks for `if` statements
+containing `continue` in their THEN branch adds unnecessary branching and
+nesting to the code. Having an else block containing just `continue` can
+also be better written by grouping the statements following the whole `if`
+statement within the THEN block and omitting the else block completely.
+
+### Example
+```
+while condition() {
+    update_condition();
+    if x {
+        // ...
+    } else {
+        continue;
+    }
+    println!("Hello, world");
+}
+```
+
+Could be rewritten as
+
+```
+while condition() {
+    update_condition();
+    if x {
+        // ...
+        println!("Hello, world");
+    }
+}
+```
+
+As another example, the following code
+
+```
+loop {
+    if waiting() {
+        continue;
+    } else {
+        // Do something useful
+    }
+    # break;
+}
+```
+Could be rewritten as
+
+```
+loop {
+    if waiting() {
+        continue;
+    }
+    // Do something useful
+    # break;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_doctest_main.txt b/src/tools/clippy/src/docs/needless_doctest_main.txt
new file mode 100644
index 000000000000..8f91a7baa715
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_doctest_main.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for `fn main() { .. }` in doctests
+
+### Why is this bad?
+The test can be shorter (and likely more readable)
+if the `fn main()` is left implicit.
+
+### Examples
+```
+/// An example of a doctest with a `main()` function
+///
+/// # Examples
+///
+/// ```
+/// fn main() {
+///     // this needs not be in an `fn`
+/// }
+/// ```
+fn needless_main() {
+    unimplemented!();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_for_each.txt b/src/tools/clippy/src/docs/needless_for_each.txt
new file mode 100644
index 000000000000..9ae6dd360c8f
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_for_each.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for usage of `for_each` that would be more simply written as a
+`for` loop.
+
+### Why is this bad?
+`for_each` may be used after applying iterator transformers like
+`filter` for better readability and performance. It may also be used to fit a simple
+operation on one line.
+But when none of these apply, a simple `for` loop is more idiomatic.
+
+### Example
+```
+let v = vec![0, 1, 2];
+v.iter().for_each(|elem| {
+    println!("{}", elem);
+})
+```
+Use instead:
+```
+let v = vec![0, 1, 2];
+for elem in v.iter() {
+    println!("{}", elem);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_late_init.txt b/src/tools/clippy/src/docs/needless_late_init.txt
new file mode 100644
index 000000000000..9e7bbcea9982
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_late_init.txt
@@ -0,0 +1,42 @@
+### What it does
+Checks for late initializations that can be replaced by a `let` statement
+with an initializer.
+
+### Why is this bad?
+Assigning in the `let` statement is less repetitive.
+
+### Example
+```
+let a;
+a = 1;
+
+let b;
+match 3 {
+    0 => b = "zero",
+    1 => b = "one",
+    _ => b = "many",
+}
+
+let c;
+if true {
+    c = 1;
+} else {
+    c = -1;
+}
+```
+Use instead:
+```
+let a = 1;
+
+let b = match 3 {
+    0 => "zero",
+    1 => "one",
+    _ => "many",
+};
+
+let c = if true {
+    1
+} else {
+    -1
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_lifetimes.txt b/src/tools/clippy/src/docs/needless_lifetimes.txt
new file mode 100644
index 000000000000..b280caa66b58
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_lifetimes.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for lifetime annotations which can be removed by
+relying on lifetime elision.
+
+### Why is this bad?
+The additional lifetimes make the code look more
+complicated, while there is nothing out of the ordinary going on. Removing
+them leads to more readable code.
+
+### Known problems
+- We bail out if the function has a `where` clause where lifetimes
+are mentioned due to potential false positives.
+- Lifetime bounds such as `impl Foo + 'a` and `T: 'a` must be elided with the
+placeholder notation `'_` because the fully elided notation leaves the type bound to `'static`.
+
+### Example
+```
+// Unnecessary lifetime annotations
+fn in_and_out<'a>(x: &'a u8, y: u8) -> &'a u8 {
+    x
+}
+```
+
+Use instead:
+```
+fn elided(x: &u8, y: u8) -> &u8 {
+    x
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_match.txt b/src/tools/clippy/src/docs/needless_match.txt
new file mode 100644
index 000000000000..92b40a5df648
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_match.txt
@@ -0,0 +1,36 @@
+### What it does
+Checks for unnecessary `match` or match-like `if let` returns for `Option` and `Result`
+when function signatures are the same.
+
+### Why is this bad?
+This `match` block does nothing and might not be what the coder intended.
+
+### Example
+```
+fn foo() -> Result<(), i32> {
+    match result {
+        Ok(val) => Ok(val),
+        Err(err) => Err(err),
+    }
+}
+
+fn bar() -> Option<i32> {
+    if let Some(val) = option {
+        Some(val)
+    } else {
+        None
+    }
+}
+```
+
+Could be replaced as
+
+```
+fn foo() -> Result<(), i32> {
+    result
+}
+
+fn bar() -> Option<i32> {
+    option
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_option_as_deref.txt b/src/tools/clippy/src/docs/needless_option_as_deref.txt
new file mode 100644
index 000000000000..226396c97ac4
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_option_as_deref.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for no-op uses of `Option::{as_deref, as_deref_mut}`,
+for example, `Option<&T>::as_deref()` returns the same type.
+
+### Why is this bad?
+Redundant code and improving readability.
+
+### Example
+```
+let a = Some(&1);
+let b = a.as_deref(); // goes from Option<&i32> to Option<&i32>
+```
+
+Use instead:
+```
+let a = Some(&1);
+let b = a;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_option_take.txt b/src/tools/clippy/src/docs/needless_option_take.txt
new file mode 100644
index 000000000000..6bac65a13b5b
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_option_take.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for calling `take` function after `as_ref`.
+
+### Why is this bad?
+Redundant code. `take` writes `None` to its argument.
+In this case the modification is useless as it's a temporary that cannot be read from afterwards.
+
+### Example
+```
+let x = Some(3);
+x.as_ref().take();
+```
+Use instead:
+```
+let x = Some(3);
+x.as_ref();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_parens_on_range_literals.txt b/src/tools/clippy/src/docs/needless_parens_on_range_literals.txt
new file mode 100644
index 000000000000..85fab10cb5f6
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_parens_on_range_literals.txt
@@ -0,0 +1,23 @@
+### What it does
+The lint checks for parenthesis on literals in range statements that are
+superfluous.
+
+### Why is this bad?
+Having superfluous parenthesis makes the code less readable
+overhead when reading.
+
+### Example
+
+```
+for i in (0)..10 {
+  println!("{i}");
+}
+```
+
+Use instead:
+
+```
+for i in 0..10 {
+  println!("{i}");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_pass_by_value.txt b/src/tools/clippy/src/docs/needless_pass_by_value.txt
new file mode 100644
index 000000000000..58c420b19f62
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_pass_by_value.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for functions taking arguments by value, but not
+consuming them in its
+body.
+
+### Why is this bad?
+Taking arguments by reference is more flexible and can
+sometimes avoid
+unnecessary allocations.
+
+### Known problems
+* This lint suggests taking an argument by reference,
+however sometimes it is better to let users decide the argument type
+(by using `Borrow` trait, for example), depending on how the function is used.
+
+### Example
+```
+fn foo(v: Vec<i32>) {
+    assert_eq!(v.len(), 42);
+}
+```
+should be
+```
+fn foo(v: &[i32]) {
+    assert_eq!(v.len(), 42);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_question_mark.txt b/src/tools/clippy/src/docs/needless_question_mark.txt
new file mode 100644
index 000000000000..540739fd45fa
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_question_mark.txt
@@ -0,0 +1,43 @@
+### What it does
+Suggests alternatives for useless applications of `?` in terminating expressions
+
+### Why is this bad?
+There's no reason to use `?` to short-circuit when execution of the body will end there anyway.
+
+### Example
+```
+struct TO {
+    magic: Option<usize>,
+}
+
+fn f(to: TO) -> Option<usize> {
+    Some(to.magic?)
+}
+
+struct TR {
+    magic: Result<usize, bool>,
+}
+
+fn g(tr: Result<TR, bool>) -> Result<usize, bool> {
+    tr.and_then(|t| Ok(t.magic?))
+}
+
+```
+Use instead:
+```
+struct TO {
+    magic: Option<usize>,
+}
+
+fn f(to: TO) -> Option<usize> {
+   to.magic
+}
+
+struct TR {
+    magic: Result<usize, bool>,
+}
+
+fn g(tr: Result<TR, bool>) -> Result<usize, bool> {
+    tr.and_then(|t| t.magic)
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_range_loop.txt b/src/tools/clippy/src/docs/needless_range_loop.txt
new file mode 100644
index 000000000000..583c09b28497
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_range_loop.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for looping over the range of `0..len` of some
+collection just to get the values by index.
+
+### Why is this bad?
+Just iterating the collection itself makes the intent
+more clear and is probably faster.
+
+### Example
+```
+let vec = vec!['a', 'b', 'c'];
+for i in 0..vec.len() {
+    println!("{}", vec[i]);
+}
+```
+
+Use instead:
+```
+let vec = vec!['a', 'b', 'c'];
+for i in vec {
+    println!("{}", i);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_return.txt b/src/tools/clippy/src/docs/needless_return.txt
new file mode 100644
index 000000000000..48782cb0ca84
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_return.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for return statements at the end of a block.
+
+### Why is this bad?
+Removing the `return` and semicolon will make the code
+more rusty.
+
+### Example
+```
+fn foo(x: usize) -> usize {
+    return x;
+}
+```
+simplify to
+```
+fn foo(x: usize) -> usize {
+    x
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_splitn.txt b/src/tools/clippy/src/docs/needless_splitn.txt
new file mode 100644
index 000000000000..b10a84fbc42d
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_splitn.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usages of `str::splitn` (or `str::rsplitn`) where using `str::split` would be the same.
+### Why is this bad?
+The function `split` is simpler and there is no performance difference in these cases, considering
+that both functions return a lazy iterator.
+### Example
+```
+let str = "key=value=add";
+let _ = str.splitn(3, '=').next().unwrap();
+```
+
+Use instead:
+```
+let str = "key=value=add";
+let _ = str.split('=').next().unwrap();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/needless_update.txt b/src/tools/clippy/src/docs/needless_update.txt
new file mode 100644
index 000000000000..82adabf6482c
--- /dev/null
+++ b/src/tools/clippy/src/docs/needless_update.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for needlessly including a base struct on update
+when all fields are changed anyway.
+
+This lint is not applied to structs marked with
+[non_exhaustive](https://doc.rust-lang.org/reference/attributes/type_system.html).
+
+### Why is this bad?
+This will cost resources (because the base has to be
+somewhere), and make the code less readable.
+
+### Example
+```
+Point {
+    x: 1,
+    y: 1,
+    z: 1,
+    ..zero_point
+};
+```
+
+Use instead:
+```
+// Missing field `z`
+Point {
+    x: 1,
+    y: 1,
+    ..zero_point
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/neg_cmp_op_on_partial_ord.txt b/src/tools/clippy/src/docs/neg_cmp_op_on_partial_ord.txt
new file mode 100644
index 000000000000..fa55c6cfd74b
--- /dev/null
+++ b/src/tools/clippy/src/docs/neg_cmp_op_on_partial_ord.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for the usage of negated comparison operators on types which only implement
+`PartialOrd` (e.g., `f64`).
+
+### Why is this bad?
+These operators make it easy to forget that the underlying types actually allow not only three
+potential Orderings (Less, Equal, Greater) but also a fourth one (Uncomparable). This is
+especially easy to miss if the operator based comparison result is negated.
+
+### Example
+```
+let a = 1.0;
+let b = f64::NAN;
+
+let not_less_or_equal = !(a <= b);
+```
+
+Use instead:
+```
+use std::cmp::Ordering;
+
+let _not_less_or_equal = match a.partial_cmp(&b) {
+    None | Some(Ordering::Greater) => true,
+    _ => false,
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/neg_multiply.txt b/src/tools/clippy/src/docs/neg_multiply.txt
new file mode 100644
index 000000000000..4e8b096eb9cc
--- /dev/null
+++ b/src/tools/clippy/src/docs/neg_multiply.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for multiplication by -1 as a form of negation.
+
+### Why is this bad?
+It's more readable to just negate.
+
+### Known problems
+This only catches integers (for now).
+
+### Example
+```
+let a = x * -1;
+```
+
+Use instead:
+```
+let a = -x;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/negative_feature_names.txt b/src/tools/clippy/src/docs/negative_feature_names.txt
new file mode 100644
index 000000000000..01ee9efb318b
--- /dev/null
+++ b/src/tools/clippy/src/docs/negative_feature_names.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for negative feature names with prefix `no-` or `not-`
+
+### Why is this bad?
+Features are supposed to be additive, and negatively-named features violate it.
+
+### Example
+```
+[features]
+default = []
+no-abc = []
+not-def = []
+
+```
+Use instead:
+```
+[features]
+default = ["abc", "def"]
+abc = []
+def = []
+
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/never_loop.txt b/src/tools/clippy/src/docs/never_loop.txt
new file mode 100644
index 000000000000..737ccf415cb9
--- /dev/null
+++ b/src/tools/clippy/src/docs/never_loop.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for loops that will always `break`, `return` or
+`continue` an outer loop.
+
+### Why is this bad?
+This loop never loops, all it does is obfuscating the
+code.
+
+### Example
+```
+loop {
+    ..;
+    break;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/new_ret_no_self.txt b/src/tools/clippy/src/docs/new_ret_no_self.txt
new file mode 100644
index 000000000000..291bad24a643
--- /dev/null
+++ b/src/tools/clippy/src/docs/new_ret_no_self.txt
@@ -0,0 +1,47 @@
+### What it does
+Checks for `new` not returning a type that contains `Self`.
+
+### Why is this bad?
+As a convention, `new` methods are used to make a new
+instance of a type.
+
+### Example
+In an impl block:
+```
+impl Foo {
+    fn new() -> NotAFoo {
+    }
+}
+```
+
+```
+struct Bar(Foo);
+impl Foo {
+    // Bad. The type name must contain `Self`
+    fn new() -> Bar {
+    }
+}
+```
+
+```
+impl Foo {
+    // Good. Return type contains `Self`
+    fn new() -> Result<Foo, FooError> {
+    }
+}
+```
+
+Or in a trait definition:
+```
+pub trait Trait {
+    // Bad. The type name must contain `Self`
+    fn new();
+}
+```
+
+```
+pub trait Trait {
+    // Good. Return type contains `Self`
+    fn new() -> Self;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/new_without_default.txt b/src/tools/clippy/src/docs/new_without_default.txt
new file mode 100644
index 000000000000..662d39c8efdd
--- /dev/null
+++ b/src/tools/clippy/src/docs/new_without_default.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for public types with a `pub fn new() -> Self` method and no
+implementation of
+[`Default`](https://doc.rust-lang.org/std/default/trait.Default.html).
+
+### Why is this bad?
+The user might expect to be able to use
+[`Default`](https://doc.rust-lang.org/std/default/trait.Default.html) as the
+type can be constructed without arguments.
+
+### Example
+```
+pub struct Foo(Bar);
+
+impl Foo {
+    pub fn new() -> Self {
+        Foo(Bar::new())
+    }
+}
+```
+
+To fix the lint, add a `Default` implementation that delegates to `new`:
+
+```
+pub struct Foo(Bar);
+
+impl Default for Foo {
+    fn default() -> Self {
+        Foo::new()
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/no_effect.txt b/src/tools/clippy/src/docs/no_effect.txt
new file mode 100644
index 000000000000..d4cc08fa8a7d
--- /dev/null
+++ b/src/tools/clippy/src/docs/no_effect.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for statements which have no effect.
+
+### Why is this bad?
+Unlike dead code, these statements are actually
+executed. However, as they have no effect, all they do is make the code less
+readable.
+
+### Example
+```
+0;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/no_effect_replace.txt b/src/tools/clippy/src/docs/no_effect_replace.txt
new file mode 100644
index 000000000000..646d45287ef5
--- /dev/null
+++ b/src/tools/clippy/src/docs/no_effect_replace.txt
@@ -0,0 +1,11 @@
+### What it does
+Checks for `replace` statements which have no effect.
+
+### Why is this bad?
+It's either a mistake or confusing.
+
+### Example
+```
+"1234".replace("12", "12");
+"1234".replacen("12", "12", 1);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/no_effect_underscore_binding.txt b/src/tools/clippy/src/docs/no_effect_underscore_binding.txt
new file mode 100644
index 000000000000..972f60dd01e9
--- /dev/null
+++ b/src/tools/clippy/src/docs/no_effect_underscore_binding.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for binding to underscore prefixed variable without side-effects.
+
+### Why is this bad?
+Unlike dead code, these bindings are actually
+executed. However, as they have no effect and shouldn't be used further on, all they
+do is make the code less readable.
+
+### Known problems
+Further usage of this variable is not checked, which can lead to false positives if it is
+used later in the code.
+
+### Example
+```
+let _i_serve_no_purpose = 1;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/non_ascii_literal.txt b/src/tools/clippy/src/docs/non_ascii_literal.txt
new file mode 100644
index 000000000000..164902b4726e
--- /dev/null
+++ b/src/tools/clippy/src/docs/non_ascii_literal.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for non-ASCII characters in string and char literals.
+
+### Why is this bad?
+Yeah, we know, the 90's called and wanted their charset
+back. Even so, there still are editors and other programs out there that
+don't work well with Unicode. So if the code is meant to be used
+internationally, on multiple operating systems, or has other portability
+requirements, activating this lint could be useful.
+
+### Example
+```
+let x = String::from("€");
+```
+
+Use instead:
+```
+let x = String::from("\u{20ac}");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/non_octal_unix_permissions.txt b/src/tools/clippy/src/docs/non_octal_unix_permissions.txt
new file mode 100644
index 000000000000..4a468e94db16
--- /dev/null
+++ b/src/tools/clippy/src/docs/non_octal_unix_permissions.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for non-octal values used to set Unix file permissions.
+
+### Why is this bad?
+They will be converted into octal, creating potentially
+unintended file permissions.
+
+### Example
+```
+use std::fs::OpenOptions;
+use std::os::unix::fs::OpenOptionsExt;
+
+let mut options = OpenOptions::new();
+options.mode(644);
+```
+Use instead:
+```
+use std::fs::OpenOptions;
+use std::os::unix::fs::OpenOptionsExt;
+
+let mut options = OpenOptions::new();
+options.mode(0o644);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/non_send_fields_in_send_ty.txt b/src/tools/clippy/src/docs/non_send_fields_in_send_ty.txt
new file mode 100644
index 000000000000..11e6f6e162cf
--- /dev/null
+++ b/src/tools/clippy/src/docs/non_send_fields_in_send_ty.txt
@@ -0,0 +1,36 @@
+### What it does
+This lint warns about a `Send` implementation for a type that
+contains fields that are not safe to be sent across threads.
+It tries to detect fields that can cause a soundness issue
+when sent to another thread (e.g., `Rc`) while allowing `!Send` fields
+that are expected to exist in a `Send` type, such as raw pointers.
+
+### Why is this bad?
+Sending the struct to another thread effectively sends all of its fields,
+and the fields that do not implement `Send` can lead to soundness bugs
+such as data races when accessed in a thread
+that is different from the thread that created it.
+
+See:
+* [*The Rustonomicon* about *Send and Sync*](https://doc.rust-lang.org/nomicon/send-and-sync.html)
+* [The documentation of `Send`](https://doc.rust-lang.org/std/marker/trait.Send.html)
+
+### Known Problems
+This lint relies on heuristics to distinguish types that are actually
+unsafe to be sent across threads and `!Send` types that are expected to
+exist in  `Send` type. Its rule can filter out basic cases such as
+`Vec<*const T>`, but it's not perfect. Feel free to create an issue if
+you have a suggestion on how this heuristic can be improved.
+
+### Example
+```
+struct ExampleStruct<T> {
+    rc_is_not_send: Rc<String>,
+    unbounded_generic_field: T,
+}
+
+// This impl is unsound because it allows sending `!Send` types through `ExampleStruct`
+unsafe impl<T> Send for ExampleStruct<T> {}
+```
+Use thread-safe types like [`std::sync::Arc`](https://doc.rust-lang.org/std/sync/struct.Arc.html)
+or specify correct bounds on generic type parameters (`T: Send`).
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/nonminimal_bool.txt b/src/tools/clippy/src/docs/nonminimal_bool.txt
new file mode 100644
index 000000000000..488980ddf023
--- /dev/null
+++ b/src/tools/clippy/src/docs/nonminimal_bool.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for boolean expressions that can be written more
+concisely.
+
+### Why is this bad?
+Readability of boolean expressions suffers from
+unnecessary duplication.
+
+### Known problems
+Ignores short circuiting behavior of `||` and
+`&&`. Ignores `|`, `&` and `^`.
+
+### Example
+```
+if a && true {}
+if !(a == b) {}
+```
+
+Use instead:
+```
+if a {}
+if a != b {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/nonsensical_open_options.txt b/src/tools/clippy/src/docs/nonsensical_open_options.txt
new file mode 100644
index 000000000000..7a95443b51a5
--- /dev/null
+++ b/src/tools/clippy/src/docs/nonsensical_open_options.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for duplicate open options as well as combinations
+that make no sense.
+
+### Why is this bad?
+In the best case, the code will be harder to read than
+necessary. I don't know the worst case.
+
+### Example
+```
+use std::fs::OpenOptions;
+
+OpenOptions::new().read(true).truncate(true);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/nonstandard_macro_braces.txt b/src/tools/clippy/src/docs/nonstandard_macro_braces.txt
new file mode 100644
index 000000000000..7e8d0d2d33bf
--- /dev/null
+++ b/src/tools/clippy/src/docs/nonstandard_macro_braces.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks that common macros are used with consistent bracing.
+
+### Why is this bad?
+This is mostly a consistency lint although using () or []
+doesn't give you a semicolon in item position, which can be unexpected.
+
+### Example
+```
+vec!{1, 2, 3};
+```
+Use instead:
+```
+vec![1, 2, 3];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/not_unsafe_ptr_arg_deref.txt b/src/tools/clippy/src/docs/not_unsafe_ptr_arg_deref.txt
new file mode 100644
index 000000000000..31355fbb7b66
--- /dev/null
+++ b/src/tools/clippy/src/docs/not_unsafe_ptr_arg_deref.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for public functions that dereference raw pointer
+arguments but are not marked `unsafe`.
+
+### Why is this bad?
+The function should probably be marked `unsafe`, since
+for an arbitrary raw pointer, there is no way of telling for sure if it is
+valid.
+
+### Known problems
+* It does not check functions recursively so if the pointer is passed to a
+private non-`unsafe` function which does the dereferencing, the lint won't
+trigger.
+* It only checks for arguments whose type are raw pointers, not raw pointers
+got from an argument in some other way (`fn foo(bar: &[*const u8])` or
+`some_argument.get_raw_ptr()`).
+
+### Example
+```
+pub fn foo(x: *const u8) {
+    println!("{}", unsafe { *x });
+}
+```
+
+Use instead:
+```
+pub unsafe fn foo(x: *const u8) {
+    println!("{}", unsafe { *x });
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/obfuscated_if_else.txt b/src/tools/clippy/src/docs/obfuscated_if_else.txt
new file mode 100644
index 000000000000..638f63b0db5e
--- /dev/null
+++ b/src/tools/clippy/src/docs/obfuscated_if_else.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for usages of `.then_some(..).unwrap_or(..)`
+
+### Why is this bad?
+This can be written more clearly with `if .. else ..`
+
+### Limitations
+This lint currently only looks for usages of
+`.then_some(..).unwrap_or(..)`, but will be expanded
+to account for similar patterns.
+
+### Example
+```
+let x = true;
+x.then_some("a").unwrap_or("b");
+```
+Use instead:
+```
+let x = true;
+if x { "a" } else { "b" };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/octal_escapes.txt b/src/tools/clippy/src/docs/octal_escapes.txt
new file mode 100644
index 000000000000..eee820587158
--- /dev/null
+++ b/src/tools/clippy/src/docs/octal_escapes.txt
@@ -0,0 +1,33 @@
+### What it does
+Checks for `\0` escapes in string and byte literals that look like octal
+character escapes in C.
+
+### Why is this bad?
+
+C and other languages support octal character escapes in strings, where
+a backslash is followed by up to three octal digits. For example, `\033`
+stands for the ASCII character 27 (ESC). Rust does not support this
+notation, but has the escape code `\0` which stands for a null
+byte/character, and any following digits do not form part of the escape
+sequence. Therefore, `\033` is not a compiler error but the result may
+be surprising.
+
+### Known problems
+The actual meaning can be the intended one. `\x00` can be used in these
+cases to be unambiguous.
+
+The lint does not trigger for format strings in `print!()`, `write!()`
+and friends since the string is already preprocessed when Clippy lints
+can see it.
+
+### Example
+```
+let one = "\033[1m Bold? \033[0m";  // \033 intended as escape
+let two = "\033\0";                 // \033 intended as null-3-3
+```
+
+Use instead:
+```
+let one = "\x1b[1mWill this be bold?\x1b[0m";
+let two = "\x0033\x00";
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ok_expect.txt b/src/tools/clippy/src/docs/ok_expect.txt
new file mode 100644
index 000000000000..fd5205d49dc0
--- /dev/null
+++ b/src/tools/clippy/src/docs/ok_expect.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `ok().expect(..)`.
+
+### Why is this bad?
+Because you usually call `expect()` on the `Result`
+directly to get a better error message.
+
+### Known problems
+The error type needs to implement `Debug`
+
+### Example
+```
+x.ok().expect("why did I do this again?");
+```
+
+Use instead:
+```
+x.expect("why did I do this again?");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/only_used_in_recursion.txt b/src/tools/clippy/src/docs/only_used_in_recursion.txt
new file mode 100644
index 000000000000..f19f47ff9eb5
--- /dev/null
+++ b/src/tools/clippy/src/docs/only_used_in_recursion.txt
@@ -0,0 +1,58 @@
+### What it does
+Checks for arguments that are only used in recursion with no side-effects.
+
+### Why is this bad?
+It could contain a useless calculation and can make function simpler.
+
+The arguments can be involved in calculations and assignments but as long as
+the calculations have no side-effects (function calls or mutating dereference)
+and the assigned variables are also only in recursion, it is useless.
+
+### Known problems
+Too many code paths in the linting code are currently untested and prone to produce false
+positives or are prone to have performance implications.
+
+In some cases, this would not catch all useless arguments.
+
+```
+fn foo(a: usize, b: usize) -> usize {
+    let f = |x| x + 1;
+
+    if a == 0 {
+        1
+    } else {
+        foo(a - 1, f(b))
+    }
+}
+```
+
+For example, the argument `b` is only used in recursion, but the lint would not catch it.
+
+List of some examples that can not be caught:
+- binary operation of non-primitive types
+- closure usage
+- some `break` relative operations
+- struct pattern binding
+
+Also, when you recurse the function name with path segments, it is not possible to detect.
+
+### Example
+```
+fn f(a: usize, b: usize) -> usize {
+    if a == 0 {
+        1
+    } else {
+        f(a - 1, b + 1)
+    }
+}
+```
+Use instead:
+```
+fn f(a: usize) -> usize {
+    if a == 0 {
+        1
+    } else {
+        f(a - 1)
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/op_ref.txt b/src/tools/clippy/src/docs/op_ref.txt
new file mode 100644
index 000000000000..7a7ed1bc9bad
--- /dev/null
+++ b/src/tools/clippy/src/docs/op_ref.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for arguments to `==` which have their address
+taken to satisfy a bound
+and suggests to dereference the other argument instead
+
+### Why is this bad?
+It is more idiomatic to dereference the other argument.
+
+### Example
+```
+&x == y
+```
+
+Use instead:
+```
+x == *y
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_as_ref_deref.txt b/src/tools/clippy/src/docs/option_as_ref_deref.txt
new file mode 100644
index 000000000000..ad7411d3d4bd
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_as_ref_deref.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for usage of `_.as_ref().map(Deref::deref)` or it's aliases (such as String::as_str).
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.as_deref()`.
+
+### Example
+```
+opt.as_ref().map(String::as_str)
+```
+Can be written as
+```
+opt.as_deref()
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_env_unwrap.txt b/src/tools/clippy/src/docs/option_env_unwrap.txt
new file mode 100644
index 000000000000..c952cba8e261
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_env_unwrap.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `option_env!(...).unwrap()` and
+suggests usage of the `env!` macro.
+
+### Why is this bad?
+Unwrapping the result of `option_env!` will panic
+at run-time if the environment variable doesn't exist, whereas `env!`
+catches it at compile-time.
+
+### Example
+```
+let _ = option_env!("HOME").unwrap();
+```
+
+Is better expressed as:
+
+```
+let _ = env!("HOME");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_filter_map.txt b/src/tools/clippy/src/docs/option_filter_map.txt
new file mode 100644
index 000000000000..25f7bde7b4d0
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_filter_map.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for indirect collection of populated `Option`
+
+### Why is this bad?
+`Option` is like a collection of 0-1 things, so `flatten`
+automatically does this without suspicious-looking `unwrap` calls.
+
+### Example
+```
+let _ = std::iter::empty::<Option<i32>>().filter(Option::is_some).map(Option::unwrap);
+```
+Use instead:
+```
+let _ = std::iter::empty::<Option<i32>>().flatten();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_if_let_else.txt b/src/tools/clippy/src/docs/option_if_let_else.txt
new file mode 100644
index 000000000000..43652db513b4
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_if_let_else.txt
@@ -0,0 +1,46 @@
+### What it does
+Lints usage of `if let Some(v) = ... { y } else { x }` and
+`match .. { Some(v) => y, None/_ => x }` which are more
+idiomatically done with `Option::map_or` (if the else bit is a pure
+expression) or `Option::map_or_else` (if the else bit is an impure
+expression).
+
+### Why is this bad?
+Using the dedicated functions of the `Option` type is clearer and
+more concise than an `if let` expression.
+
+### Known problems
+This lint uses a deliberately conservative metric for checking
+if the inside of either body contains breaks or continues which will
+cause it to not suggest a fix if either block contains a loop with
+continues or breaks contained within the loop.
+
+### Example
+```
+let _ = if let Some(foo) = optional {
+    foo
+} else {
+    5
+};
+let _ = match optional {
+    Some(val) => val + 1,
+    None => 5
+};
+let _ = if let Some(foo) = optional {
+    foo
+} else {
+    let y = do_complicated_function();
+    y*y
+};
+```
+
+should be
+
+```
+let _ = optional.map_or(5, |foo| foo);
+let _ = optional.map_or(5, |val| val + 1);
+let _ = optional.map_or_else(||{
+    let y = do_complicated_function();
+    y*y
+}, |foo| foo);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_map_or_none.txt b/src/tools/clippy/src/docs/option_map_or_none.txt
new file mode 100644
index 000000000000..c86c65215f01
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_map_or_none.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `_.map_or(None, _)`.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.and_then(_)`.
+
+### Known problems
+The order of the arguments is not in execution order.
+
+### Example
+```
+opt.map_or(None, |a| Some(a + 1));
+```
+
+Use instead:
+```
+opt.and_then(|a| Some(a + 1));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_map_unit_fn.txt b/src/tools/clippy/src/docs/option_map_unit_fn.txt
new file mode 100644
index 000000000000..fc4b528f0923
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_map_unit_fn.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for usage of `option.map(f)` where f is a function
+or closure that returns the unit type `()`.
+
+### Why is this bad?
+Readability, this can be written more clearly with
+an if let statement
+
+### Example
+```
+let x: Option<String> = do_stuff();
+x.map(log_err_msg);
+x.map(|msg| log_err_msg(format_msg(msg)));
+```
+
+The correct use would be:
+
+```
+let x: Option<String> = do_stuff();
+if let Some(msg) = x {
+    log_err_msg(msg);
+}
+
+if let Some(msg) = x {
+    log_err_msg(format_msg(msg));
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/option_option.txt b/src/tools/clippy/src/docs/option_option.txt
new file mode 100644
index 000000000000..b4324bd83990
--- /dev/null
+++ b/src/tools/clippy/src/docs/option_option.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for use of `Option<Option<_>>` in function signatures and type
+definitions
+
+### Why is this bad?
+`Option<_>` represents an optional value. `Option<Option<_>>`
+represents an optional optional value which is logically the same thing as an optional
+value but has an unneeded extra level of wrapping.
+
+If you have a case where `Some(Some(_))`, `Some(None)` and `None` are distinct cases,
+consider a custom `enum` instead, with clear names for each case.
+
+### Example
+```
+fn get_data() -> Option<Option<u32>> {
+    None
+}
+```
+
+Better:
+
+```
+pub enum Contents {
+    Data(Vec<u8>), // Was Some(Some(Vec<u8>))
+    NotYetFetched, // Was Some(None)
+    None,          // Was None
+}
+
+fn get_data() -> Contents {
+    Contents::None
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/or_fun_call.txt b/src/tools/clippy/src/docs/or_fun_call.txt
new file mode 100644
index 000000000000..6ce77cc268c5
--- /dev/null
+++ b/src/tools/clippy/src/docs/or_fun_call.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for calls to `.or(foo(..))`, `.unwrap_or(foo(..))`,
+`.or_insert(foo(..))` etc., and suggests to use `.or_else(|| foo(..))`,
+`.unwrap_or_else(|| foo(..))`, `.unwrap_or_default()` or `.or_default()`
+etc. instead.
+
+### Why is this bad?
+The function will always be called and potentially
+allocate an object acting as the default.
+
+### Known problems
+If the function has side-effects, not calling it will
+change the semantic of the program, but you shouldn't rely on that anyway.
+
+### Example
+```
+foo.unwrap_or(String::new());
+```
+
+Use instead:
+```
+foo.unwrap_or_else(String::new);
+
+// or
+
+foo.unwrap_or_default();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/or_then_unwrap.txt b/src/tools/clippy/src/docs/or_then_unwrap.txt
new file mode 100644
index 000000000000..64ac53749e8a
--- /dev/null
+++ b/src/tools/clippy/src/docs/or_then_unwrap.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for `.or(…).unwrap()` calls to Options and Results.
+
+### Why is this bad?
+You should use `.unwrap_or(…)` instead for clarity.
+
+### Example
+```
+// Result
+let value = result.or::<Error>(Ok(fallback)).unwrap();
+
+// Option
+let value = option.or(Some(fallback)).unwrap();
+```
+Use instead:
+```
+// Result
+let value = result.unwrap_or(fallback);
+
+// Option
+let value = option.unwrap_or(fallback);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/out_of_bounds_indexing.txt b/src/tools/clippy/src/docs/out_of_bounds_indexing.txt
new file mode 100644
index 000000000000..5802eea29966
--- /dev/null
+++ b/src/tools/clippy/src/docs/out_of_bounds_indexing.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for out of bounds array indexing with a constant
+index.
+
+### Why is this bad?
+This will always panic at runtime.
+
+### Example
+```
+let x = [1, 2, 3, 4];
+
+x[9];
+&x[2..9];
+```
+
+Use instead:
+```
+// Index within bounds
+
+x[0];
+x[3];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/overflow_check_conditional.txt b/src/tools/clippy/src/docs/overflow_check_conditional.txt
new file mode 100644
index 000000000000..a09cc18a0bcc
--- /dev/null
+++ b/src/tools/clippy/src/docs/overflow_check_conditional.txt
@@ -0,0 +1,11 @@
+### What it does
+Detects classic underflow/overflow checks.
+
+### Why is this bad?
+Most classic C underflow/overflow checks will fail in
+Rust. Users can use functions like `overflowing_*` and `wrapping_*` instead.
+
+### Example
+```
+a + b < a;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/overly_complex_bool_expr.txt b/src/tools/clippy/src/docs/overly_complex_bool_expr.txt
new file mode 100644
index 000000000000..65ca18392e75
--- /dev/null
+++ b/src/tools/clippy/src/docs/overly_complex_bool_expr.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for boolean expressions that contain terminals that
+can be eliminated.
+
+### Why is this bad?
+This is most likely a logic bug.
+
+### Known problems
+Ignores short circuiting behavior.
+
+### Example
+```
+// The `b` is unnecessary, the expression is equivalent to `if a`.
+if a && b || a { ... }
+```
+
+Use instead:
+```
+if a {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/panic.txt b/src/tools/clippy/src/docs/panic.txt
new file mode 100644
index 000000000000..f9bdc6e87ccf
--- /dev/null
+++ b/src/tools/clippy/src/docs/panic.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for usage of `panic!`.
+
+### Why is this bad?
+`panic!` will stop the execution of the executable
+
+### Example
+```
+panic!("even with a good reason");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/panic_in_result_fn.txt b/src/tools/clippy/src/docs/panic_in_result_fn.txt
new file mode 100644
index 000000000000..51c2f8ae5a30
--- /dev/null
+++ b/src/tools/clippy/src/docs/panic_in_result_fn.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for usage of `panic!`, `unimplemented!`, `todo!`, `unreachable!` or assertions in a function of type result.
+
+### Why is this bad?
+For some codebases, it is desirable for functions of type result to return an error instead of crashing. Hence panicking macros should be avoided.
+
+### Known problems
+Functions called from a function returning a `Result` may invoke a panicking macro. This is not checked.
+
+### Example
+```
+fn result_with_panic() -> Result<bool, String>
+{
+    panic!("error");
+}
+```
+Use instead:
+```
+fn result_without_panic() -> Result<bool, String> {
+    Err(String::from("error"))
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/panicking_unwrap.txt b/src/tools/clippy/src/docs/panicking_unwrap.txt
new file mode 100644
index 000000000000..1fbc245c8ec3
--- /dev/null
+++ b/src/tools/clippy/src/docs/panicking_unwrap.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for calls of `unwrap[_err]()` that will always fail.
+
+### Why is this bad?
+If panicking is desired, an explicit `panic!()` should be used.
+
+### Known problems
+This lint only checks `if` conditions not assignments.
+So something like `let x: Option<()> = None; x.unwrap();` will not be recognized.
+
+### Example
+```
+if option.is_none() {
+    do_something_with(option.unwrap())
+}
+```
+
+This code will always panic. The if condition should probably be inverted.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/partialeq_ne_impl.txt b/src/tools/clippy/src/docs/partialeq_ne_impl.txt
new file mode 100644
index 000000000000..78f55188bab8
--- /dev/null
+++ b/src/tools/clippy/src/docs/partialeq_ne_impl.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for manual re-implementations of `PartialEq::ne`.
+
+### Why is this bad?
+`PartialEq::ne` is required to always return the
+negated result of `PartialEq::eq`, which is exactly what the default
+implementation does. Therefore, there should never be any need to
+re-implement it.
+
+### Example
+```
+struct Foo;
+
+impl PartialEq for Foo {
+   fn eq(&self, other: &Foo) -> bool { true }
+   fn ne(&self, other: &Foo) -> bool { !(self == other) }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/partialeq_to_none.txt b/src/tools/clippy/src/docs/partialeq_to_none.txt
new file mode 100644
index 000000000000..5cc07bf88435
--- /dev/null
+++ b/src/tools/clippy/src/docs/partialeq_to_none.txt
@@ -0,0 +1,24 @@
+### What it does
+
+Checks for binary comparisons to a literal `Option::None`.
+
+### Why is this bad?
+
+A programmer checking if some `foo` is `None` via a comparison `foo == None`
+is usually inspired from other programming languages (e.g. `foo is None`
+in Python).
+Checking if a value of type `Option<T>` is (not) equal to `None` in that
+way relies on `T: PartialEq` to do the comparison, which is unneeded.
+
+### Example
+```
+fn foo(f: Option<u32>) -> &'static str {
+    if f != None { "yay" } else { "nay" }
+}
+```
+Use instead:
+```
+fn foo(f: Option<u32>) -> &'static str {
+    if f.is_some() { "yay" } else { "nay" }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/path_buf_push_overwrite.txt b/src/tools/clippy/src/docs/path_buf_push_overwrite.txt
new file mode 100644
index 000000000000..34f8901da239
--- /dev/null
+++ b/src/tools/clippy/src/docs/path_buf_push_overwrite.txt
@@ -0,0 +1,25 @@
+### What it does
+* Checks for [push](https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.push)
+calls on `PathBuf` that can cause overwrites.
+
+### Why is this bad?
+Calling `push` with a root path at the start can overwrite the
+previous defined path.
+
+### Example
+```
+use std::path::PathBuf;
+
+let mut x = PathBuf::from("/foo");
+x.push("/bar");
+assert_eq!(x, PathBuf::from("/bar"));
+```
+Could be written:
+
+```
+use std::path::PathBuf;
+
+let mut x = PathBuf::from("/foo");
+x.push("bar");
+assert_eq!(x, PathBuf::from("/foo/bar"));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/pattern_type_mismatch.txt b/src/tools/clippy/src/docs/pattern_type_mismatch.txt
new file mode 100644
index 000000000000..64da881d592a
--- /dev/null
+++ b/src/tools/clippy/src/docs/pattern_type_mismatch.txt
@@ -0,0 +1,64 @@
+### What it does
+Checks for patterns that aren't exact representations of the types
+they are applied to.
+
+To satisfy this lint, you will have to adjust either the expression that is matched
+against or the pattern itself, as well as the bindings that are introduced by the
+adjusted patterns. For matching you will have to either dereference the expression
+with the `*` operator, or amend the patterns to explicitly match against `&<pattern>`
+or `&mut <pattern>` depending on the reference mutability. For the bindings you need
+to use the inverse. You can leave them as plain bindings if you wish for the value
+to be copied, but you must use `ref mut <variable>` or `ref <variable>` to construct
+a reference into the matched structure.
+
+If you are looking for a way to learn about ownership semantics in more detail, it
+is recommended to look at IDE options available to you to highlight types, lifetimes
+and reference semantics in your code. The available tooling would expose these things
+in a general way even outside of the various pattern matching mechanics. Of course
+this lint can still be used to highlight areas of interest and ensure a good understanding
+of ownership semantics.
+
+### Why is this bad?
+It isn't bad in general. But in some contexts it can be desirable
+because it increases ownership hints in the code, and will guard against some changes
+in ownership.
+
+### Example
+This example shows the basic adjustments necessary to satisfy the lint. Note how
+the matched expression is explicitly dereferenced with `*` and the `inner` variable
+is bound to a shared borrow via `ref inner`.
+
+```
+// Bad
+let value = &Some(Box::new(23));
+match value {
+    Some(inner) => println!("{}", inner),
+    None => println!("none"),
+}
+
+// Good
+let value = &Some(Box::new(23));
+match *value {
+    Some(ref inner) => println!("{}", inner),
+    None => println!("none"),
+}
+```
+
+The following example demonstrates one of the advantages of the more verbose style.
+Note how the second version uses `ref mut a` to explicitly declare `a` a shared mutable
+borrow, while `b` is simply taken by value. This ensures that the loop body cannot
+accidentally modify the wrong part of the structure.
+
+```
+// Bad
+let mut values = vec![(2, 3), (3, 4)];
+for (a, b) in &mut values {
+    *a += *b;
+}
+
+// Good
+let mut values = vec![(2, 3), (3, 4)];
+for &mut (ref mut a, b) in &mut values {
+    *a += b;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/possible_missing_comma.txt b/src/tools/clippy/src/docs/possible_missing_comma.txt
new file mode 100644
index 000000000000..5d92f4cae91e
--- /dev/null
+++ b/src/tools/clippy/src/docs/possible_missing_comma.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for possible missing comma in an array. It lints if
+an array element is a binary operator expression and it lies on two lines.
+
+### Why is this bad?
+This could lead to unexpected results.
+
+### Example
+```
+let a = &[
+    -1, -2, -3 // <= no comma here
+    -4, -5, -6
+];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/precedence.txt b/src/tools/clippy/src/docs/precedence.txt
new file mode 100644
index 000000000000..fda0b831f335
--- /dev/null
+++ b/src/tools/clippy/src/docs/precedence.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for operations where precedence may be unclear
+and suggests to add parentheses. Currently it catches the following:
+* mixed usage of arithmetic and bit shifting/combining operators without
+parentheses
+* a "negative" numeric literal (which is really a unary `-` followed by a
+numeric literal)
+  followed by a method call
+
+### Why is this bad?
+Not everyone knows the precedence of those operators by
+heart, so expressions like these may trip others trying to reason about the
+code.
+
+### Example
+* `1 << 2 + 3` equals 32, while `(1 << 2) + 3` equals 7
+* `-1i32.abs()` equals -1, while `(-1i32).abs()` equals 1
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/print_in_format_impl.txt b/src/tools/clippy/src/docs/print_in_format_impl.txt
new file mode 100644
index 000000000000..140d23d6faab
--- /dev/null
+++ b/src/tools/clippy/src/docs/print_in_format_impl.txt
@@ -0,0 +1,34 @@
+### What it does
+Checks for use of `println`, `print`, `eprintln` or `eprint` in an
+implementation of a formatting trait.
+
+### Why is this bad?
+Using a print macro is likely unintentional since formatting traits
+should write to the `Formatter`, not stdout/stderr.
+
+### Example
+```
+use std::fmt::{Display, Error, Formatter};
+
+struct S;
+impl Display for S {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
+        println!("S");
+
+        Ok(())
+    }
+}
+```
+Use instead:
+```
+use std::fmt::{Display, Error, Formatter};
+
+struct S;
+impl Display for S {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
+        writeln!(f, "S");
+
+        Ok(())
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/print_literal.txt b/src/tools/clippy/src/docs/print_literal.txt
new file mode 100644
index 000000000000..a6252a68780b
--- /dev/null
+++ b/src/tools/clippy/src/docs/print_literal.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint warns about the use of literals as `print!`/`println!` args.
+
+### Why is this bad?
+Using literals as `println!` args is inefficient
+(c.f., https://github.com/matthiaskrgr/rust-str-bench) and unnecessary
+(i.e., just put the literal in the format string)
+
+### Example
+```
+println!("{}", "foo");
+```
+use the literal without formatting:
+```
+println!("foo");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/print_stderr.txt b/src/tools/clippy/src/docs/print_stderr.txt
new file mode 100644
index 000000000000..9c6edeeef125
--- /dev/null
+++ b/src/tools/clippy/src/docs/print_stderr.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for printing on *stderr*. The purpose of this lint
+is to catch debugging remnants.
+
+### Why is this bad?
+People often print on *stderr* while debugging an
+application and might forget to remove those prints afterward.
+
+### Known problems
+Only catches `eprint!` and `eprintln!` calls.
+
+### Example
+```
+eprintln!("Hello world!");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/print_stdout.txt b/src/tools/clippy/src/docs/print_stdout.txt
new file mode 100644
index 000000000000..d2cbd811d1b2
--- /dev/null
+++ b/src/tools/clippy/src/docs/print_stdout.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for printing on *stdout*. The purpose of this lint
+is to catch debugging remnants.
+
+### Why is this bad?
+People often print on *stdout* while debugging an
+application and might forget to remove those prints afterward.
+
+### Known problems
+Only catches `print!` and `println!` calls.
+
+### Example
+```
+println!("Hello world!");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/print_with_newline.txt b/src/tools/clippy/src/docs/print_with_newline.txt
new file mode 100644
index 000000000000..640323e822db
--- /dev/null
+++ b/src/tools/clippy/src/docs/print_with_newline.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint warns when you use `print!()` with a format
+string that ends in a newline.
+
+### Why is this bad?
+You should use `println!()` instead, which appends the
+newline.
+
+### Example
+```
+print!("Hello {}!\n", name);
+```
+use println!() instead
+```
+println!("Hello {}!", name);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/println_empty_string.txt b/src/tools/clippy/src/docs/println_empty_string.txt
new file mode 100644
index 000000000000..b980413022ca
--- /dev/null
+++ b/src/tools/clippy/src/docs/println_empty_string.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint warns when you use `println!("")` to
+print a newline.
+
+### Why is this bad?
+You should use `println!()`, which is simpler.
+
+### Example
+```
+println!("");
+```
+
+Use instead:
+```
+println!();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ptr_arg.txt b/src/tools/clippy/src/docs/ptr_arg.txt
new file mode 100644
index 000000000000..796b0a65b717
--- /dev/null
+++ b/src/tools/clippy/src/docs/ptr_arg.txt
@@ -0,0 +1,29 @@
+### What it does
+This lint checks for function arguments of type `&String`, `&Vec`,
+`&PathBuf`, and `Cow<_>`. It will also suggest you replace `.clone()` calls
+with the appropriate `.to_owned()`/`to_string()` calls.
+
+### Why is this bad?
+Requiring the argument to be of the specific size
+makes the function less useful for no benefit; slices in the form of `&[T]`
+or `&str` usually suffice and can be obtained from other types, too.
+
+### Known problems
+There may be `fn(&Vec)`-typed references pointing to your function.
+If you have them, you will get a compiler error after applying this lint's
+suggestions. You then have the choice to undo your changes or change the
+type of the reference.
+
+Note that if the function is part of your public interface, there may be
+other crates referencing it, of which you may not be aware. Carefully
+deprecate the function before applying the lint suggestions in this case.
+
+### Example
+```
+fn foo(&Vec<u32>) { .. }
+```
+
+Use instead:
+```
+fn foo(&[u32]) { .. }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ptr_as_ptr.txt b/src/tools/clippy/src/docs/ptr_as_ptr.txt
new file mode 100644
index 000000000000..8fb35c4aae8f
--- /dev/null
+++ b/src/tools/clippy/src/docs/ptr_as_ptr.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for `as` casts between raw pointers without changing its mutability,
+namely `*const T` to `*const U` and `*mut T` to `*mut U`.
+
+### Why is this bad?
+Though `as` casts between raw pointers is not terrible, `pointer::cast` is safer because
+it cannot accidentally change the pointer's mutability nor cast the pointer to other types like `usize`.
+
+### Example
+```
+let ptr: *const u32 = &42_u32;
+let mut_ptr: *mut u32 = &mut 42_u32;
+let _ = ptr as *const i32;
+let _ = mut_ptr as *mut i32;
+```
+Use instead:
+```
+let ptr: *const u32 = &42_u32;
+let mut_ptr: *mut u32 = &mut 42_u32;
+let _ = ptr.cast::<i32>();
+let _ = mut_ptr.cast::<i32>();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ptr_eq.txt b/src/tools/clippy/src/docs/ptr_eq.txt
new file mode 100644
index 000000000000..06b36ca55e69
--- /dev/null
+++ b/src/tools/clippy/src/docs/ptr_eq.txt
@@ -0,0 +1,22 @@
+### What it does
+Use `std::ptr::eq` when applicable
+
+### Why is this bad?
+`ptr::eq` can be used to compare `&T` references
+(which coerce to `*const T` implicitly) by their address rather than
+comparing the values they point to.
+
+### Example
+```
+let a = &[1, 2, 3];
+let b = &[1, 2, 3];
+
+assert!(a as *const _ as usize == b as *const _ as usize);
+```
+Use instead:
+```
+let a = &[1, 2, 3];
+let b = &[1, 2, 3];
+
+assert!(std::ptr::eq(a, b));
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ptr_offset_with_cast.txt b/src/tools/clippy/src/docs/ptr_offset_with_cast.txt
new file mode 100644
index 000000000000..f204e769bf4b
--- /dev/null
+++ b/src/tools/clippy/src/docs/ptr_offset_with_cast.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for usage of the `offset` pointer method with a `usize` casted to an
+`isize`.
+
+### Why is this bad?
+If we’re always increasing the pointer address, we can avoid the numeric
+cast by using the `add` method instead.
+
+### Example
+```
+let vec = vec![b'a', b'b', b'c'];
+let ptr = vec.as_ptr();
+let offset = 1_usize;
+
+unsafe {
+    ptr.offset(offset as isize);
+}
+```
+
+Could be written:
+
+```
+let vec = vec![b'a', b'b', b'c'];
+let ptr = vec.as_ptr();
+let offset = 1_usize;
+
+unsafe {
+    ptr.add(offset);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/pub_use.txt b/src/tools/clippy/src/docs/pub_use.txt
new file mode 100644
index 000000000000..407cafa01903
--- /dev/null
+++ b/src/tools/clippy/src/docs/pub_use.txt
@@ -0,0 +1,28 @@
+### What it does
+
+Restricts the usage of `pub use ...`
+
+### Why is this bad?
+
+`pub use` is usually fine, but a project may wish to limit `pub use` instances to prevent
+unintentional exports or to encourage placing exported items directly in public modules
+
+### Example
+```
+pub mod outer {
+    mod inner {
+        pub struct Test {}
+    }
+    pub use inner::Test;
+}
+
+use outer::Test;
+```
+Use instead:
+```
+pub mod outer {
+    pub struct Test {}
+}
+
+use outer::Test;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/question_mark.txt b/src/tools/clippy/src/docs/question_mark.txt
new file mode 100644
index 000000000000..4dc987be8813
--- /dev/null
+++ b/src/tools/clippy/src/docs/question_mark.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for expressions that could be replaced by the question mark operator.
+
+### Why is this bad?
+Question mark usage is more idiomatic.
+
+### Example
+```
+if option.is_none() {
+    return None;
+}
+```
+
+Could be written:
+
+```
+option?;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/range_minus_one.txt b/src/tools/clippy/src/docs/range_minus_one.txt
new file mode 100644
index 000000000000..fcb96dcc34ed
--- /dev/null
+++ b/src/tools/clippy/src/docs/range_minus_one.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for inclusive ranges where 1 is subtracted from
+the upper bound, e.g., `x..=(y-1)`.
+
+### Why is this bad?
+The code is more readable with an exclusive range
+like `x..y`.
+
+### Known problems
+This will cause a warning that cannot be fixed if
+the consumer of the range only accepts a specific range type, instead of
+the generic `RangeBounds` trait
+([#3307](https://github.com/rust-lang/rust-clippy/issues/3307)).
+
+### Example
+```
+for i in x..=(y-1) {
+    // ..
+}
+```
+
+Use instead:
+```
+for i in x..y {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/range_plus_one.txt b/src/tools/clippy/src/docs/range_plus_one.txt
new file mode 100644
index 000000000000..193c85f9cbc7
--- /dev/null
+++ b/src/tools/clippy/src/docs/range_plus_one.txt
@@ -0,0 +1,36 @@
+### What it does
+Checks for exclusive ranges where 1 is added to the
+upper bound, e.g., `x..(y+1)`.
+
+### Why is this bad?
+The code is more readable with an inclusive range
+like `x..=y`.
+
+### Known problems
+Will add unnecessary pair of parentheses when the
+expression is not wrapped in a pair but starts with an opening parenthesis
+and ends with a closing one.
+I.e., `let _ = (f()+1)..(f()+1)` results in `let _ = ((f()+1)..=f())`.
+
+Also in many cases, inclusive ranges are still slower to run than
+exclusive ranges, because they essentially add an extra branch that
+LLVM may fail to hoist out of the loop.
+
+This will cause a warning that cannot be fixed if the consumer of the
+range only accepts a specific range type, instead of the generic
+`RangeBounds` trait
+([#3307](https://github.com/rust-lang/rust-clippy/issues/3307)).
+
+### Example
+```
+for i in x..(y+1) {
+    // ..
+}
+```
+
+Use instead:
+```
+for i in x..=y {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/range_zip_with_len.txt b/src/tools/clippy/src/docs/range_zip_with_len.txt
new file mode 100644
index 000000000000..24c1efec789a
--- /dev/null
+++ b/src/tools/clippy/src/docs/range_zip_with_len.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for zipping a collection with the range of
+`0.._.len()`.
+
+### Why is this bad?
+The code is better expressed with `.enumerate()`.
+
+### Example
+```
+let _ = x.iter().zip(0..x.len());
+```
+
+Use instead:
+```
+let _ = x.iter().enumerate();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/rc_buffer.txt b/src/tools/clippy/src/docs/rc_buffer.txt
new file mode 100644
index 000000000000..82ac58eeb308
--- /dev/null
+++ b/src/tools/clippy/src/docs/rc_buffer.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for `Rc<T>` and `Arc<T>` when `T` is a mutable buffer type such as `String` or `Vec`.
+
+### Why is this bad?
+Expressions such as `Rc<String>` usually have no advantage over `Rc<str>`, since
+it is larger and involves an extra level of indirection, and doesn't implement `Borrow<str>`.
+
+While mutating a buffer type would still be possible with `Rc::get_mut()`, it only
+works if there are no additional references yet, which usually defeats the purpose of
+enclosing it in a shared ownership type. Instead, additionally wrapping the inner
+type with an interior mutable container (such as `RefCell` or `Mutex`) would normally
+be used.
+
+### Known problems
+This pattern can be desirable to avoid the overhead of a `RefCell` or `Mutex` for
+cases where mutation only happens before there are any additional references.
+
+### Example
+```
+fn foo(interned: Rc<String>) { ... }
+```
+
+Better:
+
+```
+fn foo(interned: Rc<str>) { ... }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/rc_clone_in_vec_init.txt b/src/tools/clippy/src/docs/rc_clone_in_vec_init.txt
new file mode 100644
index 000000000000..6fc08aaf9ab5
--- /dev/null
+++ b/src/tools/clippy/src/docs/rc_clone_in_vec_init.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for reference-counted pointers (`Arc`, `Rc`, `rc::Weak`, and `sync::Weak`)
+in `vec![elem; len]`
+
+### Why is this bad?
+This will create `elem` once and clone it `len` times - doing so with `Arc`/`Rc`/`Weak`
+is a bit misleading, as it will create references to the same pointer, rather
+than different instances.
+
+### Example
+```
+let v = vec![std::sync::Arc::new("some data".to_string()); 100];
+// or
+let v = vec![std::rc::Rc::new("some data".to_string()); 100];
+```
+Use instead:
+```
+// Initialize each value separately:
+let mut data = Vec::with_capacity(100);
+for _ in 0..100 {
+    data.push(std::rc::Rc::new("some data".to_string()));
+}
+
+// Or if you want clones of the same reference,
+// Create the reference beforehand to clarify that
+// it should be cloned for each value
+let data = std::rc::Rc::new("some data".to_string());
+let v = vec![data; 100];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/rc_mutex.txt b/src/tools/clippy/src/docs/rc_mutex.txt
new file mode 100644
index 000000000000..ed7a1e344d08
--- /dev/null
+++ b/src/tools/clippy/src/docs/rc_mutex.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for `Rc<Mutex<T>>`.
+
+### Why is this bad?
+`Rc` is used in single thread and `Mutex` is used in multi thread.
+Consider using `Rc<RefCell<T>>` in single thread or `Arc<Mutex<T>>` in multi thread.
+
+### Known problems
+Sometimes combining generic types can lead to the requirement that a
+type use Rc in conjunction with Mutex. We must consider those cases false positives, but
+alas they are quite hard to rule out. Luckily they are also rare.
+
+### Example
+```
+use std::rc::Rc;
+use std::sync::Mutex;
+fn foo(interned: Rc<Mutex<i32>>) { ... }
+```
+
+Better:
+
+```
+use std::rc::Rc;
+use std::cell::RefCell
+fn foo(interned: Rc<RefCell<i32>>) { ... }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/read_zero_byte_vec.txt b/src/tools/clippy/src/docs/read_zero_byte_vec.txt
new file mode 100644
index 000000000000..cef5604e01c0
--- /dev/null
+++ b/src/tools/clippy/src/docs/read_zero_byte_vec.txt
@@ -0,0 +1,30 @@
+### What it does
+This lint catches reads into a zero-length `Vec`.
+Especially in the case of a call to `with_capacity`, this lint warns that read
+gets the number of bytes from the `Vec`'s length, not its capacity.
+
+### Why is this bad?
+Reading zero bytes is almost certainly not the intended behavior.
+
+### Known problems
+In theory, a very unusual read implementation could assign some semantic meaning
+to zero-byte reads. But it seems exceptionally unlikely that code intending to do
+a zero-byte read would allocate a `Vec` for it.
+
+### Example
+```
+use std::io;
+fn foo<F: io::Read>(mut f: F) {
+    let mut data = Vec::with_capacity(100);
+    f.read(&mut data).unwrap();
+}
+```
+Use instead:
+```
+use std::io;
+fn foo<F: io::Read>(mut f: F) {
+    let mut data = Vec::with_capacity(100);
+    data.resize(100, 0);
+    f.read(&mut data).unwrap();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/recursive_format_impl.txt b/src/tools/clippy/src/docs/recursive_format_impl.txt
new file mode 100644
index 000000000000..32fffd84cf43
--- /dev/null
+++ b/src/tools/clippy/src/docs/recursive_format_impl.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for format trait implementations (e.g. `Display`) with a recursive call to itself
+which uses `self` as a parameter.
+This is typically done indirectly with the `write!` macro or with `to_string()`.
+
+### Why is this bad?
+This will lead to infinite recursion and a stack overflow.
+
+### Example
+
+```
+use std::fmt;
+
+struct Structure(i32);
+impl fmt::Display for Structure {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.to_string())
+    }
+}
+
+```
+Use instead:
+```
+use std::fmt;
+
+struct Structure(i32);
+impl fmt::Display for Structure {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_allocation.txt b/src/tools/clippy/src/docs/redundant_allocation.txt
new file mode 100644
index 000000000000..86bf51e8dfec
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_allocation.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for use of redundant allocations anywhere in the code.
+
+### Why is this bad?
+Expressions such as `Rc<&T>`, `Rc<Rc<T>>`, `Rc<Arc<T>>`, `Rc<Box<T>>`, `Arc<&T>`, `Arc<Rc<T>>`,
+`Arc<Arc<T>>`, `Arc<Box<T>>`, `Box<&T>`, `Box<Rc<T>>`, `Box<Arc<T>>`, `Box<Box<T>>`, add an unnecessary level of indirection.
+
+### Example
+```
+fn foo(bar: Rc<&usize>) {}
+```
+
+Better:
+
+```
+fn foo(bar: &usize) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_clone.txt b/src/tools/clippy/src/docs/redundant_clone.txt
new file mode 100644
index 000000000000..b29aed0b5e77
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_clone.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for a redundant `clone()` (and its relatives) which clones an owned
+value that is going to be dropped without further use.
+
+### Why is this bad?
+It is not always possible for the compiler to eliminate useless
+allocations and deallocations generated by redundant `clone()`s.
+
+### Known problems
+False-negatives: analysis performed by this lint is conservative and limited.
+
+### Example
+```
+{
+    let x = Foo::new();
+    call(x.clone());
+    call(x.clone()); // this can just pass `x`
+}
+
+["lorem", "ipsum"].join(" ").to_string();
+
+Path::new("/a/b").join("c").to_path_buf();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_closure.txt b/src/tools/clippy/src/docs/redundant_closure.txt
new file mode 100644
index 000000000000..0faa9513f97f
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_closure.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for closures which just call another function where
+the function can be called directly. `unsafe` functions or calls where types
+get adjusted are ignored.
+
+### Why is this bad?
+Needlessly creating a closure adds code for no benefit
+and gives the optimizer more work.
+
+### Known problems
+If creating the closure inside the closure has a side-
+effect then moving the closure creation out will change when that side-
+effect runs.
+See [#1439](https://github.com/rust-lang/rust-clippy/issues/1439) for more details.
+
+### Example
+```
+xs.map(|x| foo(x))
+```
+
+Use instead:
+```
+// where `foo(_)` is a plain function that takes the exact argument type of `x`.
+xs.map(foo)
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_closure_call.txt b/src/tools/clippy/src/docs/redundant_closure_call.txt
new file mode 100644
index 000000000000..913d1a705e29
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_closure_call.txt
@@ -0,0 +1,17 @@
+### What it does
+Detects closures called in the same expression where they
+are defined.
+
+### Why is this bad?
+It is unnecessarily adding to the expression's
+complexity.
+
+### Example
+```
+let a = (|| 42)();
+```
+
+Use instead:
+```
+let a = 42;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_closure_for_method_calls.txt b/src/tools/clippy/src/docs/redundant_closure_for_method_calls.txt
new file mode 100644
index 000000000000..865510e14755
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_closure_for_method_calls.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for closures which only invoke a method on the closure
+argument and can be replaced by referencing the method directly.
+
+### Why is this bad?
+It's unnecessary to create the closure.
+
+### Example
+```
+Some('a').map(|s| s.to_uppercase());
+```
+may be rewritten as
+```
+Some('a').map(char::to_uppercase);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_else.txt b/src/tools/clippy/src/docs/redundant_else.txt
new file mode 100644
index 000000000000..3f4e86917603
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_else.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for `else` blocks that can be removed without changing semantics.
+
+### Why is this bad?
+The `else` block adds unnecessary indentation and verbosity.
+
+### Known problems
+Some may prefer to keep the `else` block for clarity.
+
+### Example
+```
+fn my_func(count: u32) {
+    if count == 0 {
+        print!("Nothing to do");
+        return;
+    } else {
+        print!("Moving on...");
+    }
+}
+```
+Use instead:
+```
+fn my_func(count: u32) {
+    if count == 0 {
+        print!("Nothing to do");
+        return;
+    }
+    print!("Moving on...");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_feature_names.txt b/src/tools/clippy/src/docs/redundant_feature_names.txt
new file mode 100644
index 000000000000..5bd6925ed47d
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_feature_names.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for feature names with prefix `use-`, `with-` or suffix `-support`
+
+### Why is this bad?
+These prefixes and suffixes have no significant meaning.
+
+### Example
+```
+[features]
+default = ["use-abc", "with-def", "ghi-support"]
+use-abc = []  // redundant
+with-def = []   // redundant
+ghi-support = []   // redundant
+```
+
+Use instead:
+```
+[features]
+default = ["abc", "def", "ghi"]
+abc = []
+def = []
+ghi = []
+```
diff --git a/src/tools/clippy/src/docs/redundant_field_names.txt b/src/tools/clippy/src/docs/redundant_field_names.txt
new file mode 100644
index 000000000000..35f20a466b37
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_field_names.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for fields in struct literals where shorthands
+could be used.
+
+### Why is this bad?
+If the field and variable names are the same,
+the field name is redundant.
+
+### Example
+```
+let bar: u8 = 123;
+
+struct Foo {
+    bar: u8,
+}
+
+let foo = Foo { bar: bar };
+```
+the last line can be simplified to
+```
+let foo = Foo { bar };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_pattern.txt b/src/tools/clippy/src/docs/redundant_pattern.txt
new file mode 100644
index 000000000000..45f6cfc86702
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_pattern.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for patterns in the form `name @ _`.
+
+### Why is this bad?
+It's almost always more readable to just use direct
+bindings.
+
+### Example
+```
+match v {
+    Some(x) => (),
+    y @ _ => (),
+}
+```
+
+Use instead:
+```
+match v {
+    Some(x) => (),
+    y => (),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_pattern_matching.txt b/src/tools/clippy/src/docs/redundant_pattern_matching.txt
new file mode 100644
index 000000000000..77b1021e0db3
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_pattern_matching.txt
@@ -0,0 +1,45 @@
+### What it does
+Lint for redundant pattern matching over `Result`, `Option`,
+`std::task::Poll` or `std::net::IpAddr`
+
+### Why is this bad?
+It's more concise and clear to just use the proper
+utility function
+
+### Known problems
+This will change the drop order for the matched type. Both `if let` and
+`while let` will drop the value at the end of the block, both `if` and `while` will drop the
+value before entering the block. For most types this change will not matter, but for a few
+types this will not be an acceptable change (e.g. locks). See the
+[reference](https://doc.rust-lang.org/reference/destructors.html#drop-scopes) for more about
+drop order.
+
+### Example
+```
+if let Ok(_) = Ok::<i32, i32>(42) {}
+if let Err(_) = Err::<i32, i32>(42) {}
+if let None = None::<()> {}
+if let Some(_) = Some(42) {}
+if let Poll::Pending = Poll::Pending::<()> {}
+if let Poll::Ready(_) = Poll::Ready(42) {}
+if let IpAddr::V4(_) = IpAddr::V4(Ipv4Addr::LOCALHOST) {}
+if let IpAddr::V6(_) = IpAddr::V6(Ipv6Addr::LOCALHOST) {}
+match Ok::<i32, i32>(42) {
+    Ok(_) => true,
+    Err(_) => false,
+};
+```
+
+The more idiomatic use would be:
+
+```
+if Ok::<i32, i32>(42).is_ok() {}
+if Err::<i32, i32>(42).is_err() {}
+if None::<()>.is_none() {}
+if Some(42).is_some() {}
+if Poll::Pending::<()>.is_pending() {}
+if Poll::Ready(42).is_ready() {}
+if IpAddr::V4(Ipv4Addr::LOCALHOST).is_ipv4() {}
+if IpAddr::V6(Ipv6Addr::LOCALHOST).is_ipv6() {}
+Ok::<i32, i32>(42).is_ok();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_pub_crate.txt b/src/tools/clippy/src/docs/redundant_pub_crate.txt
new file mode 100644
index 000000000000..a527bb5acda1
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_pub_crate.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for items declared `pub(crate)` that are not crate visible because they
+are inside a private module.
+
+### Why is this bad?
+Writing `pub(crate)` is misleading when it's redundant due to the parent
+module's visibility.
+
+### Example
+```
+mod internal {
+    pub(crate) fn internal_fn() { }
+}
+```
+This function is not visible outside the module and it can be declared with `pub` or
+private visibility
+```
+mod internal {
+    pub fn internal_fn() { }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_slicing.txt b/src/tools/clippy/src/docs/redundant_slicing.txt
new file mode 100644
index 000000000000..6798911ed76c
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_slicing.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for redundant slicing expressions which use the full range, and
+do not change the type.
+
+### Why is this bad?
+It unnecessarily adds complexity to the expression.
+
+### Known problems
+If the type being sliced has an implementation of `Index<RangeFull>`
+that actually changes anything then it can't be removed. However, this would be surprising
+to people reading the code and should have a note with it.
+
+### Example
+```
+fn get_slice(x: &[u32]) -> &[u32] {
+    &x[..]
+}
+```
+Use instead:
+```
+fn get_slice(x: &[u32]) -> &[u32] {
+    x
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/redundant_static_lifetimes.txt b/src/tools/clippy/src/docs/redundant_static_lifetimes.txt
new file mode 100644
index 000000000000..edb8e7b5c62b
--- /dev/null
+++ b/src/tools/clippy/src/docs/redundant_static_lifetimes.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for constants and statics with an explicit `'static` lifetime.
+
+### Why is this bad?
+Adding `'static` to every reference can create very
+complicated types.
+
+### Example
+```
+const FOO: &'static [(&'static str, &'static str, fn(&Bar) -> bool)] =
+&[...]
+static FOO: &'static [(&'static str, &'static str, fn(&Bar) -> bool)] =
+&[...]
+```
+This code can be rewritten as
+```
+ const FOO: &[(&str, &str, fn(&Bar) -> bool)] = &[...]
+ static FOO: &[(&str, &str, fn(&Bar) -> bool)] = &[...]
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ref_binding_to_reference.txt b/src/tools/clippy/src/docs/ref_binding_to_reference.txt
new file mode 100644
index 000000000000..dc391cd988e5
--- /dev/null
+++ b/src/tools/clippy/src/docs/ref_binding_to_reference.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for `ref` bindings which create a reference to a reference.
+
+### Why is this bad?
+The address-of operator at the use site is clearer about the need for a reference.
+
+### Example
+```
+let x = Some("");
+if let Some(ref x) = x {
+    // use `x` here
+}
+```
+
+Use instead:
+```
+let x = Some("");
+if let Some(x) = x {
+    // use `&x` here
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/ref_option_ref.txt b/src/tools/clippy/src/docs/ref_option_ref.txt
new file mode 100644
index 000000000000..951c7bd7f7ec
--- /dev/null
+++ b/src/tools/clippy/src/docs/ref_option_ref.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for usage of `&Option<&T>`.
+
+### Why is this bad?
+Since `&` is Copy, it's useless to have a
+reference on `Option<&T>`.
+
+### Known problems
+It may be irrelevant to use this lint on
+public API code as it will make a breaking change to apply it.
+
+### Example
+```
+let x: &Option<&u32> = &Some(&0u32);
+```
+Use instead:
+```
+let x: Option<&u32> = Some(&0u32);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/repeat_once.txt b/src/tools/clippy/src/docs/repeat_once.txt
new file mode 100644
index 000000000000..3ba189c1945d
--- /dev/null
+++ b/src/tools/clippy/src/docs/repeat_once.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for usage of `.repeat(1)` and suggest the following method for each types.
+- `.to_string()` for `str`
+- `.clone()` for `String`
+- `.to_vec()` for `slice`
+
+The lint will evaluate constant expressions and values as arguments of `.repeat(..)` and emit a message if
+they are equivalent to `1`. (Related discussion in [rust-clippy#7306](https://github.com/rust-lang/rust-clippy/issues/7306))
+
+### Why is this bad?
+For example, `String.repeat(1)` is equivalent to `.clone()`. If cloning
+the string is the intention behind this, `clone()` should be used.
+
+### Example
+```
+fn main() {
+    let x = String::from("hello world").repeat(1);
+}
+```
+Use instead:
+```
+fn main() {
+    let x = String::from("hello world").clone();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/rest_pat_in_fully_bound_structs.txt b/src/tools/clippy/src/docs/rest_pat_in_fully_bound_structs.txt
new file mode 100644
index 000000000000..40ebbe754a37
--- /dev/null
+++ b/src/tools/clippy/src/docs/rest_pat_in_fully_bound_structs.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for unnecessary '..' pattern binding on struct when all fields are explicitly matched.
+
+### Why is this bad?
+Correctness and readability. It's like having a wildcard pattern after
+matching all enum variants explicitly.
+
+### Example
+```
+let a = A { a: 5 };
+
+match a {
+    A { a: 5, .. } => {},
+    _ => {},
+}
+```
+
+Use instead:
+```
+match a {
+    A { a: 5 } => {},
+    _ => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/result_large_err.txt b/src/tools/clippy/src/docs/result_large_err.txt
new file mode 100644
index 000000000000..e5fab3c5cfcf
--- /dev/null
+++ b/src/tools/clippy/src/docs/result_large_err.txt
@@ -0,0 +1,36 @@
+### What it does
+Checks for functions that return `Result` with an unusually large
+`Err`-variant.
+
+### Why is this bad?
+A `Result` is at least as large as the `Err`-variant. While we
+expect that variant to be seldomly used, the compiler needs to reserve
+and move that much memory every single time.
+
+### Known problems
+The size determined by Clippy is platform-dependent.
+
+### Examples
+```
+pub enum ParseError {
+    UnparsedBytes([u8; 512]),
+    UnexpectedEof,
+}
+
+// The `Result` has at least 512 bytes, even in the `Ok`-case
+pub fn parse() -> Result<(), ParseError> {
+    Ok(())
+}
+```
+should be
+```
+pub enum ParseError {
+    UnparsedBytes(Box<[u8; 512]>),
+    UnexpectedEof,
+}
+
+// The `Result` is slightly larger than a pointer
+pub fn parse() -> Result<(), ParseError> {
+    Ok(())
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/result_map_or_into_option.txt b/src/tools/clippy/src/docs/result_map_or_into_option.txt
new file mode 100644
index 000000000000..899d98c307c8
--- /dev/null
+++ b/src/tools/clippy/src/docs/result_map_or_into_option.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of `_.map_or(None, Some)`.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.ok()`.
+
+### Example
+```
+assert_eq!(Some(1), r.map_or(None, Some));
+```
+
+Use instead:
+```
+assert_eq!(Some(1), r.ok());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/result_map_unit_fn.txt b/src/tools/clippy/src/docs/result_map_unit_fn.txt
new file mode 100644
index 000000000000..3455c5c1f9b8
--- /dev/null
+++ b/src/tools/clippy/src/docs/result_map_unit_fn.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for usage of `result.map(f)` where f is a function
+or closure that returns the unit type `()`.
+
+### Why is this bad?
+Readability, this can be written more clearly with
+an if let statement
+
+### Example
+```
+let x: Result<String, String> = do_stuff();
+x.map(log_err_msg);
+x.map(|msg| log_err_msg(format_msg(msg)));
+```
+
+The correct use would be:
+
+```
+let x: Result<String, String> = do_stuff();
+if let Ok(msg) = x {
+    log_err_msg(msg);
+};
+if let Ok(msg) = x {
+    log_err_msg(format_msg(msg));
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/result_unit_err.txt b/src/tools/clippy/src/docs/result_unit_err.txt
new file mode 100644
index 000000000000..7c8ec2ffcf94
--- /dev/null
+++ b/src/tools/clippy/src/docs/result_unit_err.txt
@@ -0,0 +1,40 @@
+### What it does
+Checks for public functions that return a `Result`
+with an `Err` type of `()`. It suggests using a custom type that
+implements `std::error::Error`.
+
+### Why is this bad?
+Unit does not implement `Error` and carries no
+further information about what went wrong.
+
+### Known problems
+Of course, this lint assumes that `Result` is used
+for a fallible operation (which is after all the intended use). However
+code may opt to (mis)use it as a basic two-variant-enum. In that case,
+the suggestion is misguided, and the code should use a custom enum
+instead.
+
+### Examples
+```
+pub fn read_u8() -> Result<u8, ()> { Err(()) }
+```
+should become
+```
+use std::fmt;
+
+#[derive(Debug)]
+pub struct EndOfStream;
+
+impl fmt::Display for EndOfStream {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "End of Stream")
+    }
+}
+
+impl std::error::Error for EndOfStream { }
+
+pub fn read_u8() -> Result<u8, EndOfStream> { Err(EndOfStream) }
+```
+
+Note that there are crates that simplify creating the error type, e.g.
+[`thiserror`](https://docs.rs/thiserror).
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/return_self_not_must_use.txt b/src/tools/clippy/src/docs/return_self_not_must_use.txt
new file mode 100644
index 000000000000..4a4fd2c6e517
--- /dev/null
+++ b/src/tools/clippy/src/docs/return_self_not_must_use.txt
@@ -0,0 +1,46 @@
+### What it does
+This lint warns when a method returning `Self` doesn't have the `#[must_use]` attribute.
+
+### Why is this bad?
+Methods returning `Self` often create new values, having the `#[must_use]` attribute
+prevents users from "forgetting" to use the newly created value.
+
+The `#[must_use]` attribute can be added to the type itself to ensure that instances
+are never forgotten. Functions returning a type marked with `#[must_use]` will not be
+linted, as the usage is already enforced by the type attribute.
+
+### Limitations
+This lint is only applied on methods taking a `self` argument. It would be mostly noise
+if it was added on constructors for example.
+
+### Example
+```
+pub struct Bar;
+impl Bar {
+    // Missing attribute
+    pub fn bar(&self) -> Self {
+        Self
+    }
+}
+```
+
+Use instead:
+```
+// It's better to have the `#[must_use]` attribute on the method like this:
+pub struct Bar;
+impl Bar {
+    #[must_use]
+    pub fn bar(&self) -> Self {
+        Self
+    }
+}
+
+// Or on the type definition like this:
+#[must_use]
+pub struct Bar;
+impl Bar {
+    pub fn bar(&self) -> Self {
+        Self
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/reversed_empty_ranges.txt b/src/tools/clippy/src/docs/reversed_empty_ranges.txt
new file mode 100644
index 000000000000..39f481193866
--- /dev/null
+++ b/src/tools/clippy/src/docs/reversed_empty_ranges.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for range expressions `x..y` where both `x` and `y`
+are constant and `x` is greater or equal to `y`.
+
+### Why is this bad?
+Empty ranges yield no values so iterating them is a no-op.
+Moreover, trying to use a reversed range to index a slice will panic at run-time.
+
+### Example
+```
+fn main() {
+    (10..=0).for_each(|x| println!("{}", x));
+
+    let arr = [1, 2, 3, 4, 5];
+    let sub = &arr[3..1];
+}
+```
+Use instead:
+```
+fn main() {
+    (0..=10).rev().for_each(|x| println!("{}", x));
+
+    let arr = [1, 2, 3, 4, 5];
+    let sub = &arr[1..3];
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/same_functions_in_if_condition.txt b/src/tools/clippy/src/docs/same_functions_in_if_condition.txt
new file mode 100644
index 000000000000..a0a90eec681e
--- /dev/null
+++ b/src/tools/clippy/src/docs/same_functions_in_if_condition.txt
@@ -0,0 +1,41 @@
+### What it does
+Checks for consecutive `if`s with the same function call.
+
+### Why is this bad?
+This is probably a copy & paste error.
+Despite the fact that function can have side effects and `if` works as
+intended, such an approach is implicit and can be considered a "code smell".
+
+### Example
+```
+if foo() == bar {
+    …
+} else if foo() == bar {
+    …
+}
+```
+
+This probably should be:
+```
+if foo() == bar {
+    …
+} else if foo() == baz {
+    …
+}
+```
+
+or if the original code was not a typo and called function mutates a state,
+consider move the mutation out of the `if` condition to avoid similarity to
+a copy & paste error:
+
+```
+let first = foo();
+if first == bar {
+    …
+} else {
+    let second = foo();
+    if second == bar {
+    …
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/same_item_push.txt b/src/tools/clippy/src/docs/same_item_push.txt
new file mode 100644
index 000000000000..7e724073f8aa
--- /dev/null
+++ b/src/tools/clippy/src/docs/same_item_push.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks whether a for loop is being used to push a constant
+value into a Vec.
+
+### Why is this bad?
+This kind of operation can be expressed more succinctly with
+`vec![item; SIZE]` or `vec.resize(NEW_SIZE, item)` and using these alternatives may also
+have better performance.
+
+### Example
+```
+let item1 = 2;
+let item2 = 3;
+let mut vec: Vec<u8> = Vec::new();
+for _ in 0..20 {
+   vec.push(item1);
+}
+for _ in 0..30 {
+    vec.push(item2);
+}
+```
+
+Use instead:
+```
+let item1 = 2;
+let item2 = 3;
+let mut vec: Vec<u8> = vec![item1; 20];
+vec.resize(20 + 30, item2);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/same_name_method.txt b/src/tools/clippy/src/docs/same_name_method.txt
new file mode 100644
index 000000000000..792dd717fc64
--- /dev/null
+++ b/src/tools/clippy/src/docs/same_name_method.txt
@@ -0,0 +1,23 @@
+### What it does
+It lints if a struct has two methods with the same name:
+one from a trait, another not from trait.
+
+### Why is this bad?
+Confusing.
+
+### Example
+```
+trait T {
+    fn foo(&self) {}
+}
+
+struct S;
+
+impl T for S {
+    fn foo(&self) {}
+}
+
+impl S {
+    fn foo(&self) {}
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/search_is_some.txt b/src/tools/clippy/src/docs/search_is_some.txt
new file mode 100644
index 000000000000..67292d54585f
--- /dev/null
+++ b/src/tools/clippy/src/docs/search_is_some.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for an iterator or string search (such as `find()`,
+`position()`, or `rposition()`) followed by a call to `is_some()` or `is_none()`.
+
+### Why is this bad?
+Readability, this can be written more concisely as:
+* `_.any(_)`, or `_.contains(_)` for `is_some()`,
+* `!_.any(_)`, or `!_.contains(_)` for `is_none()`.
+
+### Example
+```
+let vec = vec![1];
+vec.iter().find(|x| **x == 0).is_some();
+
+"hello world".find("world").is_none();
+```
+
+Use instead:
+```
+let vec = vec![1];
+vec.iter().any(|x| *x == 0);
+
+!"hello world".contains("world");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/self_assignment.txt b/src/tools/clippy/src/docs/self_assignment.txt
new file mode 100644
index 000000000000..ea60ea077ab5
--- /dev/null
+++ b/src/tools/clippy/src/docs/self_assignment.txt
@@ -0,0 +1,32 @@
+### What it does
+Checks for explicit self-assignments.
+
+### Why is this bad?
+Self-assignments are redundant and unlikely to be
+intentional.
+
+### Known problems
+If expression contains any deref coercions or
+indexing operations they are assumed not to have any side effects.
+
+### Example
+```
+struct Event {
+    x: i32,
+}
+
+fn copy_position(a: &mut Event, b: &Event) {
+    a.x = a.x;
+}
+```
+
+Should be:
+```
+struct Event {
+    x: i32,
+}
+
+fn copy_position(a: &mut Event, b: &Event) {
+    a.x = b.x;
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/self_named_constructors.txt b/src/tools/clippy/src/docs/self_named_constructors.txt
new file mode 100644
index 000000000000..a01669a84542
--- /dev/null
+++ b/src/tools/clippy/src/docs/self_named_constructors.txt
@@ -0,0 +1,26 @@
+### What it does
+Warns when constructors have the same name as their types.
+
+### Why is this bad?
+Repeating the name of the type is redundant.
+
+### Example
+```
+struct Foo {}
+
+impl Foo {
+    pub fn foo() -> Foo {
+        Foo {}
+    }
+}
+```
+Use instead:
+```
+struct Foo {}
+
+impl Foo {
+    pub fn new() -> Foo {
+        Foo {}
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/self_named_module_files.txt b/src/tools/clippy/src/docs/self_named_module_files.txt
new file mode 100644
index 000000000000..73e805136288
--- /dev/null
+++ b/src/tools/clippy/src/docs/self_named_module_files.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks that module layout uses only `mod.rs` files.
+
+### Why is this bad?
+Having multiple module layout styles in a project can be confusing.
+
+### Example
+```
+src/
+  stuff/
+    stuff_files.rs
+  stuff.rs
+  lib.rs
+```
+Use instead:
+```
+src/
+  stuff/
+    stuff_files.rs
+    mod.rs
+  lib.rs
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/semicolon_if_nothing_returned.txt b/src/tools/clippy/src/docs/semicolon_if_nothing_returned.txt
new file mode 100644
index 000000000000..30c963ca211b
--- /dev/null
+++ b/src/tools/clippy/src/docs/semicolon_if_nothing_returned.txt
@@ -0,0 +1,20 @@
+### What it does
+Looks for blocks of expressions and fires if the last expression returns
+`()` but is not followed by a semicolon.
+
+### Why is this bad?
+The semicolon might be optional but when extending the block with new
+code, it doesn't require a change in previous last line.
+
+### Example
+```
+fn main() {
+    println!("Hello world")
+}
+```
+Use instead:
+```
+fn main() {
+    println!("Hello world");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/separated_literal_suffix.txt b/src/tools/clippy/src/docs/separated_literal_suffix.txt
new file mode 100644
index 000000000000..226a6b8a9876
--- /dev/null
+++ b/src/tools/clippy/src/docs/separated_literal_suffix.txt
@@ -0,0 +1,17 @@
+### What it does
+Warns if literal suffixes are separated by an underscore.
+To enforce separated literal suffix style,
+see the `unseparated_literal_suffix` lint.
+
+### Why is this bad?
+Suffix style should be consistent.
+
+### Example
+```
+123832_i32
+```
+
+Use instead:
+```
+123832i32
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/serde_api_misuse.txt b/src/tools/clippy/src/docs/serde_api_misuse.txt
new file mode 100644
index 000000000000..8a3c89ac11ad
--- /dev/null
+++ b/src/tools/clippy/src/docs/serde_api_misuse.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for mis-uses of the serde API.
+
+### Why is this bad?
+Serde is very finnicky about how its API should be
+used, but the type system can't be used to enforce it (yet?).
+
+### Example
+Implementing `Visitor::visit_string` but not
+`Visitor::visit_str`.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/shadow_reuse.txt b/src/tools/clippy/src/docs/shadow_reuse.txt
new file mode 100644
index 000000000000..9eb8e7ad164b
--- /dev/null
+++ b/src/tools/clippy/src/docs/shadow_reuse.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for bindings that shadow other bindings already in
+scope, while reusing the original value.
+
+### Why is this bad?
+Not too much, in fact it's a common pattern in Rust
+code. Still, some argue that name shadowing like this hurts readability,
+because a value may be bound to different things depending on position in
+the code.
+
+### Example
+```
+let x = 2;
+let x = x + 1;
+```
+use different variable name:
+```
+let x = 2;
+let y = x + 1;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/shadow_same.txt b/src/tools/clippy/src/docs/shadow_same.txt
new file mode 100644
index 000000000000..3cd96f560a5e
--- /dev/null
+++ b/src/tools/clippy/src/docs/shadow_same.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for bindings that shadow other bindings already in
+scope, while just changing reference level or mutability.
+
+### Why is this bad?
+Not much, in fact it's a very common pattern in Rust
+code. Still, some may opt to avoid it in their code base, they can set this
+lint to `Warn`.
+
+### Example
+```
+let x = &x;
+```
+
+Use instead:
+```
+let y = &x; // use different variable name
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/shadow_unrelated.txt b/src/tools/clippy/src/docs/shadow_unrelated.txt
new file mode 100644
index 000000000000..436251c520a9
--- /dev/null
+++ b/src/tools/clippy/src/docs/shadow_unrelated.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for bindings that shadow other bindings already in
+scope, either without an initialization or with one that does not even use
+the original value.
+
+### Why is this bad?
+Name shadowing can hurt readability, especially in
+large code bases, because it is easy to lose track of the active binding at
+any place in the code. This can be alleviated by either giving more specific
+names to bindings or introducing more scopes to contain the bindings.
+
+### Example
+```
+let x = y;
+let x = z; // shadows the earlier binding
+```
+
+Use instead:
+```
+let x = y;
+let w = z; // use different variable name
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/short_circuit_statement.txt b/src/tools/clippy/src/docs/short_circuit_statement.txt
new file mode 100644
index 000000000000..31492bed03d4
--- /dev/null
+++ b/src/tools/clippy/src/docs/short_circuit_statement.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for the use of short circuit boolean conditions as
+a
+statement.
+
+### Why is this bad?
+Using a short circuit boolean condition as a statement
+may hide the fact that the second part is executed or not depending on the
+outcome of the first part.
+
+### Example
+```
+f() && g(); // We should write `if f() { g(); }`.
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/should_implement_trait.txt b/src/tools/clippy/src/docs/should_implement_trait.txt
new file mode 100644
index 000000000000..02e74751ae03
--- /dev/null
+++ b/src/tools/clippy/src/docs/should_implement_trait.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for methods that should live in a trait
+implementation of a `std` trait (see [llogiq's blog
+post](http://llogiq.github.io/2015/07/30/traits.html) for further
+information) instead of an inherent implementation.
+
+### Why is this bad?
+Implementing the traits improve ergonomics for users of
+the code, often with very little cost. Also people seeing a `mul(...)`
+method
+may expect `*` to work equally, so you should have good reason to disappoint
+them.
+
+### Example
+```
+struct X;
+impl X {
+    fn add(&self, other: &X) -> X {
+        // ..
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/significant_drop_in_scrutinee.txt b/src/tools/clippy/src/docs/significant_drop_in_scrutinee.txt
new file mode 100644
index 000000000000..f869def0ddb7
--- /dev/null
+++ b/src/tools/clippy/src/docs/significant_drop_in_scrutinee.txt
@@ -0,0 +1,43 @@
+### What it does
+Check for temporaries returned from function calls in a match scrutinee that have the
+`clippy::has_significant_drop` attribute.
+
+### Why is this bad?
+The `clippy::has_significant_drop` attribute can be added to types whose Drop impls have
+an important side-effect, such as unlocking a mutex, making it important for users to be
+able to accurately understand their lifetimes. When a temporary is returned in a function
+call in a match scrutinee, its lifetime lasts until the end of the match block, which may
+be surprising.
+
+For `Mutex`es this can lead to a deadlock. This happens when the match scrutinee uses a
+function call that returns a `MutexGuard` and then tries to lock again in one of the match
+arms. In that case the `MutexGuard` in the scrutinee will not be dropped until the end of
+the match block and thus will not unlock.
+
+### Example
+```
+let mutex = Mutex::new(State {});
+
+match mutex.lock().unwrap().foo() {
+    true => {
+        mutex.lock().unwrap().bar(); // Deadlock!
+    }
+    false => {}
+};
+
+println!("All done!");
+```
+Use instead:
+```
+let mutex = Mutex::new(State {});
+
+let is_foo = mutex.lock().unwrap().foo();
+match is_foo {
+    true => {
+        mutex.lock().unwrap().bar();
+    }
+    false => {}
+};
+
+println!("All done!");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/similar_names.txt b/src/tools/clippy/src/docs/similar_names.txt
new file mode 100644
index 000000000000..13aca9c0bb75
--- /dev/null
+++ b/src/tools/clippy/src/docs/similar_names.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for names that are very similar and thus confusing.
+
+### Why is this bad?
+It's hard to distinguish between names that differ only
+by a single character.
+
+### Example
+```
+let checked_exp = something;
+let checked_expr = something_else;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_char_add_str.txt b/src/tools/clippy/src/docs/single_char_add_str.txt
new file mode 100644
index 000000000000..cf23dc0c89bb
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_char_add_str.txt
@@ -0,0 +1,18 @@
+### What it does
+Warns when using `push_str`/`insert_str` with a single-character string literal
+where `push`/`insert` with a `char` would work fine.
+
+### Why is this bad?
+It's less clear that we are pushing a single character.
+
+### Example
+```
+string.insert_str(0, "R");
+string.push_str("R");
+```
+
+Use instead:
+```
+string.insert(0, 'R');
+string.push('R');
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_char_lifetime_names.txt b/src/tools/clippy/src/docs/single_char_lifetime_names.txt
new file mode 100644
index 000000000000..92dd24bf247e
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_char_lifetime_names.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for lifetimes with names which are one character
+long.
+
+### Why is this bad?
+A single character is likely not enough to express the
+purpose of a lifetime. Using a longer name can make code
+easier to understand, especially for those who are new to
+Rust.
+
+### Known problems
+Rust programmers and learning resources tend to use single
+character lifetimes, so this lint is at odds with the
+ecosystem at large. In addition, the lifetime's purpose may
+be obvious or, rarely, expressible in one character.
+
+### Example
+```
+struct DiagnosticCtx<'a> {
+    source: &'a str,
+}
+```
+Use instead:
+```
+struct DiagnosticCtx<'src> {
+    source: &'src str,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_char_pattern.txt b/src/tools/clippy/src/docs/single_char_pattern.txt
new file mode 100644
index 000000000000..9e5ad1e7d639
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_char_pattern.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for string methods that receive a single-character
+`str` as an argument, e.g., `_.split("x")`.
+
+### Why is this bad?
+Performing these methods using a `char` is faster than
+using a `str`.
+
+### Known problems
+Does not catch multi-byte unicode characters.
+
+### Example
+```
+_.split("x");
+```
+
+Use instead:
+```
+_.split('x');
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_component_path_imports.txt b/src/tools/clippy/src/docs/single_component_path_imports.txt
new file mode 100644
index 000000000000..3a026388183e
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_component_path_imports.txt
@@ -0,0 +1,21 @@
+### What it does
+Checking for imports with single component use path.
+
+### Why is this bad?
+Import with single component use path such as `use cratename;`
+is not necessary, and thus should be removed.
+
+### Example
+```
+use regex;
+
+fn main() {
+    regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
+}
+```
+Better as
+```
+fn main() {
+    regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_element_loop.txt b/src/tools/clippy/src/docs/single_element_loop.txt
new file mode 100644
index 000000000000..6f0c15a85f77
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_element_loop.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks whether a for loop has a single element.
+
+### Why is this bad?
+There is no reason to have a loop of a
+single element.
+
+### Example
+```
+let item1 = 2;
+for item in &[item1] {
+    println!("{}", item);
+}
+```
+
+Use instead:
+```
+let item1 = 2;
+let item = &item1;
+println!("{}", item);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_match.txt b/src/tools/clippy/src/docs/single_match.txt
new file mode 100644
index 000000000000..31dde4da8489
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_match.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for matches with a single arm where an `if let`
+will usually suffice.
+
+### Why is this bad?
+Just readability – `if let` nests less than a `match`.
+
+### Example
+```
+match x {
+    Some(ref foo) => bar(foo),
+    _ => (),
+}
+```
+
+Use instead:
+```
+if let Some(ref foo) = x {
+    bar(foo);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/single_match_else.txt b/src/tools/clippy/src/docs/single_match_else.txt
new file mode 100644
index 000000000000..29a447af09b8
--- /dev/null
+++ b/src/tools/clippy/src/docs/single_match_else.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for matches with two arms where an `if let else` will
+usually suffice.
+
+### Why is this bad?
+Just readability – `if let` nests less than a `match`.
+
+### Known problems
+Personal style preferences may differ.
+
+### Example
+Using `match`:
+
+```
+match x {
+    Some(ref foo) => bar(foo),
+    _ => bar(&other_ref),
+}
+```
+
+Using `if let` with `else`:
+
+```
+if let Some(ref foo) = x {
+    bar(foo);
+} else {
+    bar(&other_ref);
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/size_of_in_element_count.txt b/src/tools/clippy/src/docs/size_of_in_element_count.txt
new file mode 100644
index 000000000000..d893ec6a2a01
--- /dev/null
+++ b/src/tools/clippy/src/docs/size_of_in_element_count.txt
@@ -0,0 +1,16 @@
+### What it does
+Detects expressions where
+`size_of::<T>` or `size_of_val::<T>` is used as a
+count of elements of type `T`
+
+### Why is this bad?
+These functions expect a count
+of `T` and not a number of bytes
+
+### Example
+```
+const SIZE: usize = 128;
+let x = [2u8; SIZE];
+let mut y = [2u8; SIZE];
+unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/skip_while_next.txt b/src/tools/clippy/src/docs/skip_while_next.txt
new file mode 100644
index 000000000000..1ec8a3a28d5b
--- /dev/null
+++ b/src/tools/clippy/src/docs/skip_while_next.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for usage of `_.skip_while(condition).next()`.
+
+### Why is this bad?
+Readability, this can be written more concisely as
+`_.find(!condition)`.
+
+### Example
+```
+vec.iter().skip_while(|x| **x == 0).next();
+```
+
+Use instead:
+```
+vec.iter().find(|x| **x != 0);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/slow_vector_initialization.txt b/src/tools/clippy/src/docs/slow_vector_initialization.txt
new file mode 100644
index 000000000000..53442e179654
--- /dev/null
+++ b/src/tools/clippy/src/docs/slow_vector_initialization.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks slow zero-filled vector initialization
+
+### Why is this bad?
+These structures are non-idiomatic and less efficient than simply using
+`vec![0; len]`.
+
+### Example
+```
+let mut vec1 = Vec::with_capacity(len);
+vec1.resize(len, 0);
+
+let mut vec1 = Vec::with_capacity(len);
+vec1.resize(vec1.capacity(), 0);
+
+let mut vec2 = Vec::with_capacity(len);
+vec2.extend(repeat(0).take(len));
+```
+
+Use instead:
+```
+let mut vec1 = vec![0; len];
+let mut vec2 = vec![0; len];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/stable_sort_primitive.txt b/src/tools/clippy/src/docs/stable_sort_primitive.txt
new file mode 100644
index 000000000000..6465dbee46b1
--- /dev/null
+++ b/src/tools/clippy/src/docs/stable_sort_primitive.txt
@@ -0,0 +1,31 @@
+### What it does
+When sorting primitive values (integers, bools, chars, as well
+as arrays, slices, and tuples of such items), it is typically better to
+use an unstable sort than a stable sort.
+
+### Why is this bad?
+Typically, using a stable sort consumes more memory and cpu cycles.
+Because values which compare equal are identical, preserving their
+relative order (the guarantee that a stable sort provides) means
+nothing, while the extra costs still apply.
+
+### Known problems
+
+As pointed out in
+[issue #8241](https://github.com/rust-lang/rust-clippy/issues/8241),
+a stable sort can instead be significantly faster for certain scenarios
+(eg. when a sorted vector is extended with new data and resorted).
+
+For more information and benchmarking results, please refer to the
+issue linked above.
+
+### Example
+```
+let mut vec = vec![2, 1, 3];
+vec.sort();
+```
+Use instead:
+```
+let mut vec = vec![2, 1, 3];
+vec.sort_unstable();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/std_instead_of_alloc.txt b/src/tools/clippy/src/docs/std_instead_of_alloc.txt
new file mode 100644
index 000000000000..c2d32704e505
--- /dev/null
+++ b/src/tools/clippy/src/docs/std_instead_of_alloc.txt
@@ -0,0 +1,18 @@
+### What it does
+
+Finds items imported through `std` when available through `alloc`.
+
+### Why is this bad?
+
+Crates which have `no_std` compatibility and require alloc may wish to ensure types are imported from
+alloc to ensure disabling `std` does not cause the crate to fail to compile. This lint is also useful
+for crates migrating to become `no_std` compatible.
+
+### Example
+```
+use std::vec::Vec;
+```
+Use instead:
+```
+use alloc::vec::Vec;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/std_instead_of_core.txt b/src/tools/clippy/src/docs/std_instead_of_core.txt
new file mode 100644
index 000000000000..f1e1518c6a62
--- /dev/null
+++ b/src/tools/clippy/src/docs/std_instead_of_core.txt
@@ -0,0 +1,18 @@
+### What it does
+
+Finds items imported through `std` when available through `core`.
+
+### Why is this bad?
+
+Crates which have `no_std` compatibility may wish to ensure types are imported from core to ensure
+disabling `std` does not cause the crate to fail to compile. This lint is also useful for crates
+migrating to become `no_std` compatible.
+
+### Example
+```
+use std::hash::Hasher;
+```
+Use instead:
+```
+use core::hash::Hasher;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/str_to_string.txt b/src/tools/clippy/src/docs/str_to_string.txt
new file mode 100644
index 000000000000..a24755223747
--- /dev/null
+++ b/src/tools/clippy/src/docs/str_to_string.txt
@@ -0,0 +1,18 @@
+### What it does
+This lint checks for `.to_string()` method calls on values of type `&str`.
+
+### Why is this bad?
+The `to_string` method is also used on other types to convert them to a string.
+When called on a `&str` it turns the `&str` into the owned variant `String`, which can be better
+expressed with `.to_owned()`.
+
+### Example
+```
+// example code where clippy issues a warning
+let _ = "str".to_string();
+```
+Use instead:
+```
+// example code which does not raise clippy warning
+let _ = "str".to_owned();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_add.txt b/src/tools/clippy/src/docs/string_add.txt
new file mode 100644
index 000000000000..23dafd0d0333
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_add.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for all instances of `x + _` where `x` is of type
+`String`, but only if [`string_add_assign`](#string_add_assign) does *not*
+match.
+
+### Why is this bad?
+It's not bad in and of itself. However, this particular
+`Add` implementation is asymmetric (the other operand need not be `String`,
+but `x` does), while addition as mathematically defined is symmetric, also
+the `String::push_str(_)` function is a perfectly good replacement.
+Therefore, some dislike it and wish not to have it in their code.
+
+That said, other people think that string addition, having a long tradition
+in other languages is actually fine, which is why we decided to make this
+particular lint `allow` by default.
+
+### Example
+```
+let x = "Hello".to_owned();
+x + ", World";
+```
+
+Use instead:
+```
+let mut x = "Hello".to_owned();
+x.push_str(", World");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_add_assign.txt b/src/tools/clippy/src/docs/string_add_assign.txt
new file mode 100644
index 000000000000..7438be855db8
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_add_assign.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for string appends of the form `x = x + y` (without
+`let`!).
+
+### Why is this bad?
+It's not really bad, but some people think that the
+`.push_str(_)` method is more readable.
+
+### Example
+```
+let mut x = "Hello".to_owned();
+x = x + ", World";
+
+// More readable
+x += ", World";
+x.push_str(", World");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_extend_chars.txt b/src/tools/clippy/src/docs/string_extend_chars.txt
new file mode 100644
index 000000000000..619ea3e11867
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_extend_chars.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for the use of `.extend(s.chars())` where s is a
+`&str` or `String`.
+
+### Why is this bad?
+`.push_str(s)` is clearer
+
+### Example
+```
+let abc = "abc";
+let def = String::from("def");
+let mut s = String::new();
+s.extend(abc.chars());
+s.extend(def.chars());
+```
+The correct use would be:
+```
+let abc = "abc";
+let def = String::from("def");
+let mut s = String::new();
+s.push_str(abc);
+s.push_str(&def);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_from_utf8_as_bytes.txt b/src/tools/clippy/src/docs/string_from_utf8_as_bytes.txt
new file mode 100644
index 000000000000..9102d73471cb
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_from_utf8_as_bytes.txt
@@ -0,0 +1,15 @@
+### What it does
+Check if the string is transformed to byte array and casted back to string.
+
+### Why is this bad?
+It's unnecessary, the string can be used directly.
+
+### Example
+```
+std::str::from_utf8(&"Hello World!".as_bytes()[6..11]).unwrap();
+```
+
+Use instead:
+```
+&"Hello World!"[6..11];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_lit_as_bytes.txt b/src/tools/clippy/src/docs/string_lit_as_bytes.txt
new file mode 100644
index 000000000000..a125b97ed656
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_lit_as_bytes.txt
@@ -0,0 +1,39 @@
+### What it does
+Checks for the `as_bytes` method called on string literals
+that contain only ASCII characters.
+
+### Why is this bad?
+Byte string literals (e.g., `b"foo"`) can be used
+instead. They are shorter but less discoverable than `as_bytes()`.
+
+### Known problems
+`"str".as_bytes()` and the suggested replacement of `b"str"` are not
+equivalent because they have different types. The former is `&[u8]`
+while the latter is `&[u8; 3]`. That means in general they will have a
+different set of methods and different trait implementations.
+
+```
+fn f(v: Vec<u8>) {}
+
+f("...".as_bytes().to_owned()); // works
+f(b"...".to_owned()); // does not work, because arg is [u8; 3] not Vec<u8>
+
+fn g(r: impl std::io::Read) {}
+
+g("...".as_bytes()); // works
+g(b"..."); // does not work
+```
+
+The actual equivalent of `"str".as_bytes()` with the same type is not
+`b"str"` but `&b"str"[..]`, which is a great deal of punctuation and not
+more readable than a function call.
+
+### Example
+```
+let bstr = "a byte string".as_bytes();
+```
+
+Use instead:
+```
+let bstr = b"a byte string";
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_slice.txt b/src/tools/clippy/src/docs/string_slice.txt
new file mode 100644
index 000000000000..3d9e49dd39eb
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_slice.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for slice operations on strings
+
+### Why is this bad?
+UTF-8 characters span multiple bytes, and it is easy to inadvertently confuse character
+counts and string indices. This may lead to panics, and should warrant some test cases
+containing wide UTF-8 characters. This lint is most useful in code that should avoid
+panics at all costs.
+
+### Known problems
+Probably lots of false positives. If an index comes from a known valid position (e.g.
+obtained via `char_indices` over the same string), it is totally OK.
+
+# Example
+```
+&"Ölkanne"[1..];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/string_to_string.txt b/src/tools/clippy/src/docs/string_to_string.txt
new file mode 100644
index 000000000000..deb7eebe7842
--- /dev/null
+++ b/src/tools/clippy/src/docs/string_to_string.txt
@@ -0,0 +1,19 @@
+### What it does
+This lint checks for `.to_string()` method calls on values of type `String`.
+
+### Why is this bad?
+The `to_string` method is also used on other types to convert them to a string.
+When called on a `String` it only clones the `String`, which can be better expressed with `.clone()`.
+
+### Example
+```
+// example code where clippy issues a warning
+let msg = String::from("Hello World");
+let _ = msg.to_string();
+```
+Use instead:
+```
+// example code which does not raise clippy warning
+let msg = String::from("Hello World");
+let _ = msg.clone();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/strlen_on_c_strings.txt b/src/tools/clippy/src/docs/strlen_on_c_strings.txt
new file mode 100644
index 000000000000..0454abf55a20
--- /dev/null
+++ b/src/tools/clippy/src/docs/strlen_on_c_strings.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for usage of `libc::strlen` on a `CString` or `CStr` value,
+and suggest calling `as_bytes().len()` or `to_bytes().len()` respectively instead.
+
+### Why is this bad?
+This avoids calling an unsafe `libc` function.
+Currently, it also avoids calculating the length.
+
+### Example
+```
+use std::ffi::CString;
+let cstring = CString::new("foo").expect("CString::new failed");
+let len = unsafe { libc::strlen(cstring.as_ptr()) };
+```
+Use instead:
+```
+use std::ffi::CString;
+let cstring = CString::new("foo").expect("CString::new failed");
+let len = cstring.as_bytes().len();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/struct_excessive_bools.txt b/src/tools/clippy/src/docs/struct_excessive_bools.txt
new file mode 100644
index 000000000000..9e197c786201
--- /dev/null
+++ b/src/tools/clippy/src/docs/struct_excessive_bools.txt
@@ -0,0 +1,29 @@
+### What it does
+Checks for excessive
+use of bools in structs.
+
+### Why is this bad?
+Excessive bools in a struct
+is often a sign that it's used as a state machine,
+which is much better implemented as an enum.
+If it's not the case, excessive bools usually benefit
+from refactoring into two-variant enums for better
+readability and API.
+
+### Example
+```
+struct S {
+    is_pending: bool,
+    is_processing: bool,
+    is_finished: bool,
+}
+```
+
+Use instead:
+```
+enum S {
+    Pending,
+    Processing,
+    Finished,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suboptimal_flops.txt b/src/tools/clippy/src/docs/suboptimal_flops.txt
new file mode 100644
index 000000000000..f1c9c665b085
--- /dev/null
+++ b/src/tools/clippy/src/docs/suboptimal_flops.txt
@@ -0,0 +1,50 @@
+### What it does
+Looks for floating-point expressions that
+can be expressed using built-in methods to improve both
+accuracy and performance.
+
+### Why is this bad?
+Negatively impacts accuracy and performance.
+
+### Example
+```
+use std::f32::consts::E;
+
+let a = 3f32;
+let _ = (2f32).powf(a);
+let _ = E.powf(a);
+let _ = a.powf(1.0 / 2.0);
+let _ = a.log(2.0);
+let _ = a.log(10.0);
+let _ = a.log(E);
+let _ = a.powf(2.0);
+let _ = a * 2.0 + 4.0;
+let _ = if a < 0.0 {
+    -a
+} else {
+    a
+};
+let _ = if a < 0.0 {
+    a
+} else {
+    -a
+};
+```
+
+is better expressed as
+
+```
+use std::f32::consts::E;
+
+let a = 3f32;
+let _ = a.exp2();
+let _ = a.exp();
+let _ = a.sqrt();
+let _ = a.log2();
+let _ = a.log10();
+let _ = a.ln();
+let _ = a.powi(2);
+let _ = a.mul_add(2.0, 4.0);
+let _ = a.abs();
+let _ = -a.abs();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_arithmetic_impl.txt b/src/tools/clippy/src/docs/suspicious_arithmetic_impl.txt
new file mode 100644
index 000000000000..d67ff279346d
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_arithmetic_impl.txt
@@ -0,0 +1,17 @@
+### What it does
+Lints for suspicious operations in impls of arithmetic operators, e.g.
+subtracting elements in an Add impl.
+
+### Why is this bad?
+This is probably a typo or copy-and-paste error and not intended.
+
+### Example
+```
+impl Add for Foo {
+    type Output = Foo;
+
+    fn add(self, other: Foo) -> Foo {
+        Foo(self.0 - other.0)
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_assignment_formatting.txt b/src/tools/clippy/src/docs/suspicious_assignment_formatting.txt
new file mode 100644
index 000000000000..b889827cdf27
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_assignment_formatting.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for use of the non-existent `=*`, `=!` and `=-`
+operators.
+
+### Why is this bad?
+This is either a typo of `*=`, `!=` or `-=` or
+confusing.
+
+### Example
+```
+a =- 42; // confusing, should it be `a -= 42` or `a = -42`?
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_else_formatting.txt b/src/tools/clippy/src/docs/suspicious_else_formatting.txt
new file mode 100644
index 000000000000..3cf2f74868eb
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_else_formatting.txt
@@ -0,0 +1,30 @@
+### What it does
+Checks for formatting of `else`. It lints if the `else`
+is followed immediately by a newline or the `else` seems to be missing.
+
+### Why is this bad?
+This is probably some refactoring remnant, even if the
+code is correct, it might look confusing.
+
+### Example
+```
+if foo {
+} { // looks like an `else` is missing here
+}
+
+if foo {
+} if bar { // looks like an `else` is missing here
+}
+
+if foo {
+} else
+
+{ // this is the `else` block of the previous `if`, but should it be?
+}
+
+if foo {
+} else
+
+if bar { // this is the `else` block of the previous `if`, but should it be?
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_map.txt b/src/tools/clippy/src/docs/suspicious_map.txt
new file mode 100644
index 000000000000..d8fa52c43fb0
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_map.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for calls to `map` followed by a `count`.
+
+### Why is this bad?
+It looks suspicious. Maybe `map` was confused with `filter`.
+If the `map` call is intentional, this should be rewritten
+using `inspect`. Or, if you intend to drive the iterator to
+completion, you can just use `for_each` instead.
+
+### Example
+```
+let _ = (0..3).map(|x| x + 2).count();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_op_assign_impl.txt b/src/tools/clippy/src/docs/suspicious_op_assign_impl.txt
new file mode 100644
index 000000000000..81abfbecae07
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_op_assign_impl.txt
@@ -0,0 +1,15 @@
+### What it does
+Lints for suspicious operations in impls of OpAssign, e.g.
+subtracting elements in an AddAssign impl.
+
+### Why is this bad?
+This is probably a typo or copy-and-paste error and not intended.
+
+### Example
+```
+impl AddAssign for Foo {
+    fn add_assign(&mut self, other: Foo) {
+        *self = *self - other;
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_operation_groupings.txt b/src/tools/clippy/src/docs/suspicious_operation_groupings.txt
new file mode 100644
index 000000000000..81ede5d3da57
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_operation_groupings.txt
@@ -0,0 +1,41 @@
+### What it does
+Checks for unlikely usages of binary operators that are almost
+certainly typos and/or copy/paste errors, given the other usages
+of binary operators nearby.
+
+### Why is this bad?
+They are probably bugs and if they aren't then they look like bugs
+and you should add a comment explaining why you are doing such an
+odd set of operations.
+
+### Known problems
+There may be some false positives if you are trying to do something
+unusual that happens to look like a typo.
+
+### Example
+```
+struct Vec3 {
+    x: f64,
+    y: f64,
+    z: f64,
+}
+
+impl Eq for Vec3 {}
+
+impl PartialEq for Vec3 {
+    fn eq(&self, other: &Self) -> bool {
+        // This should trigger the lint because `self.x` is compared to `other.y`
+        self.x == other.y && self.y == other.y && self.z == other.z
+    }
+}
+```
+Use instead:
+```
+// same as above except:
+impl PartialEq for Vec3 {
+    fn eq(&self, other: &Self) -> bool {
+        // Note we now compare other.x to self.x
+        self.x == other.x && self.y == other.y && self.z == other.z
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_splitn.txt b/src/tools/clippy/src/docs/suspicious_splitn.txt
new file mode 100644
index 000000000000..79a3dbfa6f4a
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_splitn.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for calls to [`splitn`]
+(https://doc.rust-lang.org/std/primitive.str.html#method.splitn) and
+related functions with either zero or one splits.
+
+### Why is this bad?
+These calls don't actually split the value and are
+likely to be intended as a different number.
+
+### Example
+```
+for x in s.splitn(1, ":") {
+    // ..
+}
+```
+
+Use instead:
+```
+for x in s.splitn(2, ":") {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_to_owned.txt b/src/tools/clippy/src/docs/suspicious_to_owned.txt
new file mode 100644
index 000000000000..8cbf61dc7175
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_to_owned.txt
@@ -0,0 +1,39 @@
+### What it does
+Checks for the usage of `_.to_owned()`, on a `Cow<'_, _>`.
+
+### Why is this bad?
+Calling `to_owned()` on a `Cow` creates a clone of the `Cow`
+itself, without taking ownership of the `Cow` contents (i.e.
+it's equivalent to calling `Cow::clone`).
+The similarly named `into_owned` method, on the other hand,
+clones the `Cow` contents, effectively turning any `Cow::Borrowed`
+into a `Cow::Owned`.
+
+Given the potential ambiguity, consider replacing `to_owned`
+with `clone` for better readability or, if getting a `Cow::Owned`
+was the original intent, using `into_owned` instead.
+
+### Example
+```
+let s = "Hello world!";
+let cow = Cow::Borrowed(s);
+
+let data = cow.to_owned();
+assert!(matches!(data, Cow::Borrowed(_)))
+```
+Use instead:
+```
+let s = "Hello world!";
+let cow = Cow::Borrowed(s);
+
+let data = cow.clone();
+assert!(matches!(data, Cow::Borrowed(_)))
+```
+or
+```
+let s = "Hello world!";
+let cow = Cow::Borrowed(s);
+
+let data = cow.into_owned();
+assert!(matches!(data, String))
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/suspicious_unary_op_formatting.txt b/src/tools/clippy/src/docs/suspicious_unary_op_formatting.txt
new file mode 100644
index 000000000000..06fb09db76d0
--- /dev/null
+++ b/src/tools/clippy/src/docs/suspicious_unary_op_formatting.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks the formatting of a unary operator on the right hand side
+of a binary operator. It lints if there is no space between the binary and unary operators,
+but there is a space between the unary and its operand.
+
+### Why is this bad?
+This is either a typo in the binary operator or confusing.
+
+### Example
+```
+// &&! looks like a different operator
+if foo &&! bar {}
+```
+
+Use instead:
+```
+if foo && !bar {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/swap_ptr_to_ref.txt b/src/tools/clippy/src/docs/swap_ptr_to_ref.txt
new file mode 100644
index 000000000000..0215d1e8a421
--- /dev/null
+++ b/src/tools/clippy/src/docs/swap_ptr_to_ref.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for calls to `core::mem::swap` where either parameter is derived from a pointer
+
+### Why is this bad?
+When at least one parameter to `swap` is derived from a pointer it may overlap with the
+other. This would then lead to undefined behavior.
+
+### Example
+```
+unsafe fn swap(x: &[*mut u32], y: &[*mut u32]) {
+    for (&x, &y) in x.iter().zip(y) {
+        core::mem::swap(&mut *x, &mut *y);
+    }
+}
+```
+Use instead:
+```
+unsafe fn swap(x: &[*mut u32], y: &[*mut u32]) {
+    for (&x, &y) in x.iter().zip(y) {
+        core::ptr::swap(x, y);
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/tabs_in_doc_comments.txt b/src/tools/clippy/src/docs/tabs_in_doc_comments.txt
new file mode 100644
index 000000000000..f83dbe2b73cb
--- /dev/null
+++ b/src/tools/clippy/src/docs/tabs_in_doc_comments.txt
@@ -0,0 +1,44 @@
+### What it does
+Checks doc comments for usage of tab characters.
+
+### Why is this bad?
+The rust style-guide promotes spaces instead of tabs for indentation.
+To keep a consistent view on the source, also doc comments should not have tabs.
+Also, explaining ascii-diagrams containing tabs can get displayed incorrectly when the
+display settings of the author and reader differ.
+
+### Example
+```
+///
+/// Struct to hold two strings:
+/// 	- first		one
+/// 	- second	one
+pub struct DoubleString {
+   ///
+   /// 	- First String:
+   /// 		- needs to be inside here
+   first_string: String,
+   ///
+   /// 	- Second String:
+   /// 		- needs to be inside here
+   second_string: String,
+}
+```
+
+Will be converted to:
+```
+///
+/// Struct to hold two strings:
+///     - first        one
+///     - second    one
+pub struct DoubleString {
+   ///
+   ///     - First String:
+   ///         - needs to be inside here
+   first_string: String,
+   ///
+   ///     - Second String:
+   ///         - needs to be inside here
+   second_string: String,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/temporary_assignment.txt b/src/tools/clippy/src/docs/temporary_assignment.txt
new file mode 100644
index 000000000000..195b42cf0d49
--- /dev/null
+++ b/src/tools/clippy/src/docs/temporary_assignment.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for construction of a structure or tuple just to
+assign a value in it.
+
+### Why is this bad?
+Readability. If the structure is only created to be
+updated, why not write the structure you want in the first place?
+
+### Example
+```
+(0, 0).0 = 1
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/to_digit_is_some.txt b/src/tools/clippy/src/docs/to_digit_is_some.txt
new file mode 100644
index 000000000000..eee8375adf7a
--- /dev/null
+++ b/src/tools/clippy/src/docs/to_digit_is_some.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for `.to_digit(..).is_some()` on `char`s.
+
+### Why is this bad?
+This is a convoluted way of checking if a `char` is a digit. It's
+more straight forward to use the dedicated `is_digit` method.
+
+### Example
+```
+let is_digit = c.to_digit(radix).is_some();
+```
+can be written as:
+```
+let is_digit = c.is_digit(radix);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/to_string_in_format_args.txt b/src/tools/clippy/src/docs/to_string_in_format_args.txt
new file mode 100644
index 000000000000..34b20583585a
--- /dev/null
+++ b/src/tools/clippy/src/docs/to_string_in_format_args.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for [`ToString::to_string`](https://doc.rust-lang.org/std/string/trait.ToString.html#tymethod.to_string)
+applied to a type that implements [`Display`](https://doc.rust-lang.org/std/fmt/trait.Display.html)
+in a macro that does formatting.
+
+### Why is this bad?
+Since the type implements `Display`, the use of `to_string` is
+unnecessary.
+
+### Example
+```
+println!("error: something failed at {}", Location::caller().to_string());
+```
+Use instead:
+```
+println!("error: something failed at {}", Location::caller());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/todo.txt b/src/tools/clippy/src/docs/todo.txt
new file mode 100644
index 000000000000..661eb1ac5cff
--- /dev/null
+++ b/src/tools/clippy/src/docs/todo.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for usage of `todo!`.
+
+### Why is this bad?
+This macro should not be present in production code
+
+### Example
+```
+todo!();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/too_many_arguments.txt b/src/tools/clippy/src/docs/too_many_arguments.txt
new file mode 100644
index 000000000000..4669f9f82e66
--- /dev/null
+++ b/src/tools/clippy/src/docs/too_many_arguments.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for functions with too many parameters.
+
+### Why is this bad?
+Functions with lots of parameters are considered bad
+style and reduce readability (“what does the 5th parameter mean?”). Consider
+grouping some parameters into a new type.
+
+### Example
+```
+fn foo(x: u32, y: u32, name: &str, c: Color, w: f32, h: f32, a: f32, b: f32) {
+    // ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/too_many_lines.txt b/src/tools/clippy/src/docs/too_many_lines.txt
new file mode 100644
index 000000000000..425db348bbd7
--- /dev/null
+++ b/src/tools/clippy/src/docs/too_many_lines.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for functions with a large amount of lines.
+
+### Why is this bad?
+Functions with a lot of lines are harder to understand
+due to having to look at a larger amount of code to understand what the
+function is doing. Consider splitting the body of the function into
+multiple functions.
+
+### Example
+```
+fn im_too_long() {
+    println!("");
+    // ... 100 more LoC
+    println!("");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/toplevel_ref_arg.txt b/src/tools/clippy/src/docs/toplevel_ref_arg.txt
new file mode 100644
index 000000000000..96a9e2db8b7e
--- /dev/null
+++ b/src/tools/clippy/src/docs/toplevel_ref_arg.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for function arguments and let bindings denoted as
+`ref`.
+
+### Why is this bad?
+The `ref` declaration makes the function take an owned
+value, but turns the argument into a reference (which means that the value
+is destroyed when exiting the function). This adds not much value: either
+take a reference type, or take an owned value and create references in the
+body.
+
+For let bindings, `let x = &foo;` is preferred over `let ref x = foo`. The
+type of `x` is more obvious with the former.
+
+### Known problems
+If the argument is dereferenced within the function,
+removing the `ref` will lead to errors. This can be fixed by removing the
+dereferences, e.g., changing `*x` to `x` within the function.
+
+### Example
+```
+fn foo(ref _x: u8) {}
+```
+
+Use instead:
+```
+fn foo(_x: &u8) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/trailing_empty_array.txt b/src/tools/clippy/src/docs/trailing_empty_array.txt
new file mode 100644
index 000000000000..db1908cc96d0
--- /dev/null
+++ b/src/tools/clippy/src/docs/trailing_empty_array.txt
@@ -0,0 +1,22 @@
+### What it does
+Displays a warning when a struct with a trailing zero-sized array is declared without a `repr` attribute.
+
+### Why is this bad?
+Zero-sized arrays aren't very useful in Rust itself, so such a struct is likely being created to pass to C code or in some other situation where control over memory layout matters (for example, in conjunction with manual allocation to make it easy to compute the offset of the array). Either way, `#[repr(C)]` (or another `repr` attribute) is needed.
+
+### Example
+```
+struct RarelyUseful {
+    some_field: u32,
+    last: [u32; 0],
+}
+```
+
+Use instead:
+```
+#[repr(C)]
+struct MoreOftenUseful {
+    some_field: usize,
+    last: [u32; 0],
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/trait_duplication_in_bounds.txt b/src/tools/clippy/src/docs/trait_duplication_in_bounds.txt
new file mode 100644
index 000000000000..509736bb3644
--- /dev/null
+++ b/src/tools/clippy/src/docs/trait_duplication_in_bounds.txt
@@ -0,0 +1,37 @@
+### What it does
+Checks for cases where generics are being used and multiple
+syntax specifications for trait bounds are used simultaneously.
+
+### Why is this bad?
+Duplicate bounds makes the code
+less readable than specifying them only once.
+
+### Example
+```
+fn func<T: Clone + Default>(arg: T) where T: Clone + Default {}
+```
+
+Use instead:
+```
+fn func<T: Clone + Default>(arg: T) {}
+
+// or
+
+fn func<T>(arg: T) where T: Clone + Default {}
+```
+
+```
+fn foo<T: Default + Default>(bar: T) {}
+```
+Use instead:
+```
+fn foo<T: Default>(bar: T) {}
+```
+
+```
+fn foo<T>(bar: T) where T: Default + Default {}
+```
+Use instead:
+```
+fn foo<T>(bar: T) where T: Default {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_bytes_to_str.txt b/src/tools/clippy/src/docs/transmute_bytes_to_str.txt
new file mode 100644
index 000000000000..75889b9c73ae
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_bytes_to_str.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for transmutes from a `&[u8]` to a `&str`.
+
+### Why is this bad?
+Not every byte slice is a valid UTF-8 string.
+
+### Known problems
+- [`from_utf8`] which this lint suggests using is slower than `transmute`
+as it needs to validate the input.
+If you are certain that the input is always a valid UTF-8,
+use [`from_utf8_unchecked`] which is as fast as `transmute`
+but has a semantically meaningful name.
+- You might want to handle errors returned from [`from_utf8`] instead of calling `unwrap`.
+
+[`from_utf8`]: https://doc.rust-lang.org/std/str/fn.from_utf8.html
+[`from_utf8_unchecked`]: https://doc.rust-lang.org/std/str/fn.from_utf8_unchecked.html
+
+### Example
+```
+let b: &[u8] = &[1_u8, 2_u8];
+unsafe {
+    let _: &str = std::mem::transmute(b); // where b: &[u8]
+}
+
+// should be:
+let _ = std::str::from_utf8(b).unwrap();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_float_to_int.txt b/src/tools/clippy/src/docs/transmute_float_to_int.txt
new file mode 100644
index 000000000000..1877e5a465a4
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_float_to_int.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for transmutes from a float to an integer.
+
+### Why is this bad?
+Transmutes are dangerous and error-prone, whereas `to_bits` is intuitive
+and safe.
+
+### Example
+```
+unsafe {
+    let _: u32 = std::mem::transmute(1f32);
+}
+
+// should be:
+let _: u32 = 1f32.to_bits();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_int_to_bool.txt b/src/tools/clippy/src/docs/transmute_int_to_bool.txt
new file mode 100644
index 000000000000..07c10f8d0bca
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_int_to_bool.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for transmutes from an integer to a `bool`.
+
+### Why is this bad?
+This might result in an invalid in-memory representation of a `bool`.
+
+### Example
+```
+let x = 1_u8;
+unsafe {
+    let _: bool = std::mem::transmute(x); // where x: u8
+}
+
+// should be:
+let _: bool = x != 0;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_int_to_char.txt b/src/tools/clippy/src/docs/transmute_int_to_char.txt
new file mode 100644
index 000000000000..836d22d3f99c
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_int_to_char.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for transmutes from an integer to a `char`.
+
+### Why is this bad?
+Not every integer is a Unicode scalar value.
+
+### Known problems
+- [`from_u32`] which this lint suggests using is slower than `transmute`
+as it needs to validate the input.
+If you are certain that the input is always a valid Unicode scalar value,
+use [`from_u32_unchecked`] which is as fast as `transmute`
+but has a semantically meaningful name.
+- You might want to handle `None` returned from [`from_u32`] instead of calling `unwrap`.
+
+[`from_u32`]: https://doc.rust-lang.org/std/char/fn.from_u32.html
+[`from_u32_unchecked`]: https://doc.rust-lang.org/std/char/fn.from_u32_unchecked.html
+
+### Example
+```
+let x = 1_u32;
+unsafe {
+    let _: char = std::mem::transmute(x); // where x: u32
+}
+
+// should be:
+let _ = std::char::from_u32(x).unwrap();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_int_to_float.txt b/src/tools/clippy/src/docs/transmute_int_to_float.txt
new file mode 100644
index 000000000000..75cdc62e9727
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_int_to_float.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for transmutes from an integer to a float.
+
+### Why is this bad?
+Transmutes are dangerous and error-prone, whereas `from_bits` is intuitive
+and safe.
+
+### Example
+```
+unsafe {
+    let _: f32 = std::mem::transmute(1_u32); // where x: u32
+}
+
+// should be:
+let _: f32 = f32::from_bits(1_u32);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_num_to_bytes.txt b/src/tools/clippy/src/docs/transmute_num_to_bytes.txt
new file mode 100644
index 000000000000..a2c39a1b947e
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_num_to_bytes.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for transmutes from a number to an array of `u8`
+
+### Why this is bad?
+Transmutes are dangerous and error-prone, whereas `to_ne_bytes`
+is intuitive and safe.
+
+### Example
+```
+unsafe {
+    let x: [u8; 8] = std::mem::transmute(1i64);
+}
+
+// should be
+let x: [u8; 8] = 0i64.to_ne_bytes();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_ptr_to_ptr.txt b/src/tools/clippy/src/docs/transmute_ptr_to_ptr.txt
new file mode 100644
index 000000000000..65777db98618
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_ptr_to_ptr.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for transmutes from a pointer to a pointer, or
+from a reference to a reference.
+
+### Why is this bad?
+Transmutes are dangerous, and these can instead be
+written as casts.
+
+### Example
+```
+let ptr = &1u32 as *const u32;
+unsafe {
+    // pointer-to-pointer transmute
+    let _: *const f32 = std::mem::transmute(ptr);
+    // ref-ref transmute
+    let _: &f32 = std::mem::transmute(&1u32);
+}
+// These can be respectively written:
+let _ = ptr as *const f32;
+let _ = unsafe{ &*(&1u32 as *const u32 as *const f32) };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_ptr_to_ref.txt b/src/tools/clippy/src/docs/transmute_ptr_to_ref.txt
new file mode 100644
index 000000000000..aca550f5036e
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_ptr_to_ref.txt
@@ -0,0 +1,21 @@
+### What it does
+Checks for transmutes from a pointer to a reference.
+
+### Why is this bad?
+This can always be rewritten with `&` and `*`.
+
+### Known problems
+- `mem::transmute` in statics and constants is stable from Rust 1.46.0,
+while dereferencing raw pointer is not stable yet.
+If you need to do this in those places,
+you would have to use `transmute` instead.
+
+### Example
+```
+unsafe {
+    let _: &T = std::mem::transmute(p); // where p: *const T
+}
+
+// can be written:
+let _: &T = &*p;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmute_undefined_repr.txt b/src/tools/clippy/src/docs/transmute_undefined_repr.txt
new file mode 100644
index 000000000000..5ee6aaf4ca92
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmute_undefined_repr.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for transmutes between types which do not have a representation defined relative to
+each other.
+
+### Why is this bad?
+The results of such a transmute are not defined.
+
+### Known problems
+This lint has had multiple problems in the past and was moved to `nursery`. See issue
+[#8496](https://github.com/rust-lang/rust-clippy/issues/8496) for more details.
+
+### Example
+```
+struct Foo<T>(u32, T);
+let _ = unsafe { core::mem::transmute::<Foo<u32>, Foo<i32>>(Foo(0u32, 0u32)) };
+```
+Use instead:
+```
+#[repr(C)]
+struct Foo<T>(u32, T);
+let _ = unsafe { core::mem::transmute::<Foo<u32>, Foo<i32>>(Foo(0u32, 0u32)) };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmutes_expressible_as_ptr_casts.txt b/src/tools/clippy/src/docs/transmutes_expressible_as_ptr_casts.txt
new file mode 100644
index 000000000000..b68a8cda9c74
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmutes_expressible_as_ptr_casts.txt
@@ -0,0 +1,16 @@
+### What it does
+Checks for transmutes that could be a pointer cast.
+
+### Why is this bad?
+Readability. The code tricks people into thinking that
+something complex is going on.
+
+### Example
+
+```
+unsafe { std::mem::transmute::<*const [i32], *const [u16]>(p) };
+```
+Use instead:
+```
+p as *const [u16];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/transmuting_null.txt b/src/tools/clippy/src/docs/transmuting_null.txt
new file mode 100644
index 000000000000..f8bacfc0b90b
--- /dev/null
+++ b/src/tools/clippy/src/docs/transmuting_null.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for transmute calls which would receive a null pointer.
+
+### Why is this bad?
+Transmuting a null pointer is undefined behavior.
+
+### Known problems
+Not all cases can be detected at the moment of this writing.
+For example, variables which hold a null pointer and are then fed to a `transmute`
+call, aren't detectable yet.
+
+### Example
+```
+let null_ref: &u64 = unsafe { std::mem::transmute(0 as *const u64) };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/trim_split_whitespace.txt b/src/tools/clippy/src/docs/trim_split_whitespace.txt
new file mode 100644
index 000000000000..f7e3e7858f94
--- /dev/null
+++ b/src/tools/clippy/src/docs/trim_split_whitespace.txt
@@ -0,0 +1,14 @@
+### What it does
+Warns about calling `str::trim` (or variants) before `str::split_whitespace`.
+
+### Why is this bad?
+`split_whitespace` already ignores leading and trailing whitespace.
+
+### Example
+```
+" A B C ".trim().split_whitespace();
+```
+Use instead:
+```
+" A B C ".split_whitespace();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/trivial_regex.txt b/src/tools/clippy/src/docs/trivial_regex.txt
new file mode 100644
index 000000000000..f71d667fd771
--- /dev/null
+++ b/src/tools/clippy/src/docs/trivial_regex.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for trivial [regex](https://crates.io/crates/regex)
+creation (with `Regex::new`, `RegexBuilder::new`, or `RegexSet::new`).
+
+### Why is this bad?
+Matching the regex can likely be replaced by `==` or
+`str::starts_with`, `str::ends_with` or `std::contains` or other `str`
+methods.
+
+### Known problems
+If the same regex is going to be applied to multiple
+inputs, the precomputations done by `Regex` construction can give
+significantly better performance than any of the `str`-based methods.
+
+### Example
+```
+Regex::new("^foobar")
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/trivially_copy_pass_by_ref.txt b/src/tools/clippy/src/docs/trivially_copy_pass_by_ref.txt
new file mode 100644
index 000000000000..f54cce5e2bd7
--- /dev/null
+++ b/src/tools/clippy/src/docs/trivially_copy_pass_by_ref.txt
@@ -0,0 +1,43 @@
+### What it does
+Checks for functions taking arguments by reference, where
+the argument type is `Copy` and small enough to be more efficient to always
+pass by value.
+
+### Why is this bad?
+In many calling conventions instances of structs will
+be passed through registers if they fit into two or less general purpose
+registers.
+
+### Known problems
+This lint is target register size dependent, it is
+limited to 32-bit to try and reduce portability problems between 32 and
+64-bit, but if you are compiling for 8 or 16-bit targets then the limit
+will be different.
+
+The configuration option `trivial_copy_size_limit` can be set to override
+this limit for a project.
+
+This lint attempts to allow passing arguments by reference if a reference
+to that argument is returned. This is implemented by comparing the lifetime
+of the argument and return value for equality. However, this can cause
+false positives in cases involving multiple lifetimes that are bounded by
+each other.
+
+Also, it does not take account of other similar cases where getting memory addresses
+matters; namely, returning the pointer to the argument in question,
+and passing the argument, as both references and pointers,
+to a function that needs the memory address. For further details, refer to
+[this issue](https://github.com/rust-lang/rust-clippy/issues/5953)
+that explains a real case in which this false positive
+led to an **undefined behavior** introduced with unsafe code.
+
+### Example
+
+```
+fn foo(v: &u32) {}
+```
+
+Use instead:
+```
+fn foo(v: u32) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/try_err.txt b/src/tools/clippy/src/docs/try_err.txt
new file mode 100644
index 000000000000..e3d4ef3a09df
--- /dev/null
+++ b/src/tools/clippy/src/docs/try_err.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for usages of `Err(x)?`.
+
+### Why is this bad?
+The `?` operator is designed to allow calls that
+can fail to be easily chained. For example, `foo()?.bar()` or
+`foo(bar()?)`. Because `Err(x)?` can't be used that way (it will
+always return), it is more clear to write `return Err(x)`.
+
+### Example
+```
+fn foo(fail: bool) -> Result<i32, String> {
+    if fail {
+      Err("failed")?;
+    }
+    Ok(0)
+}
+```
+Could be written:
+
+```
+fn foo(fail: bool) -> Result<i32, String> {
+    if fail {
+      return Err("failed".into());
+    }
+    Ok(0)
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/type_complexity.txt b/src/tools/clippy/src/docs/type_complexity.txt
new file mode 100644
index 000000000000..69cd87500504
--- /dev/null
+++ b/src/tools/clippy/src/docs/type_complexity.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for types used in structs, parameters and `let`
+declarations above a certain complexity threshold.
+
+### Why is this bad?
+Too complex types make the code less readable. Consider
+using a `type` definition to simplify them.
+
+### Example
+```
+struct Foo {
+    inner: Rc<Vec<Vec<Box<(u32, u32, u32, u32)>>>>,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/type_repetition_in_bounds.txt b/src/tools/clippy/src/docs/type_repetition_in_bounds.txt
new file mode 100644
index 000000000000..18ed372fd13e
--- /dev/null
+++ b/src/tools/clippy/src/docs/type_repetition_in_bounds.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint warns about unnecessary type repetitions in trait bounds
+
+### Why is this bad?
+Repeating the type for every bound makes the code
+less readable than combining the bounds
+
+### Example
+```
+pub fn foo<T>(t: T) where T: Copy, T: Clone {}
+```
+
+Use instead:
+```
+pub fn foo<T>(t: T) where T: Copy + Clone {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/undocumented_unsafe_blocks.txt b/src/tools/clippy/src/docs/undocumented_unsafe_blocks.txt
new file mode 100644
index 000000000000..f3af4753c5f7
--- /dev/null
+++ b/src/tools/clippy/src/docs/undocumented_unsafe_blocks.txt
@@ -0,0 +1,43 @@
+### What it does
+Checks for `unsafe` blocks and impls without a `// SAFETY: ` comment
+explaining why the unsafe operations performed inside
+the block are safe.
+
+Note the comment must appear on the line(s) preceding the unsafe block
+with nothing appearing in between. The following is ok:
+```
+foo(
+    // SAFETY:
+    // This is a valid safety comment
+    unsafe { *x }
+)
+```
+But neither of these are:
+```
+// SAFETY:
+// This is not a valid safety comment
+foo(
+    /* SAFETY: Neither is this */ unsafe { *x },
+);
+```
+
+### Why is this bad?
+Undocumented unsafe blocks and impls can make it difficult to
+read and maintain code, as well as uncover unsoundness
+and bugs.
+
+### Example
+```
+use std::ptr::NonNull;
+let a = &mut 42;
+
+let ptr = unsafe { NonNull::new_unchecked(a) };
+```
+Use instead:
+```
+use std::ptr::NonNull;
+let a = &mut 42;
+
+// SAFETY: references are guaranteed to be non-null.
+let ptr = unsafe { NonNull::new_unchecked(a) };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/undropped_manually_drops.txt b/src/tools/clippy/src/docs/undropped_manually_drops.txt
new file mode 100644
index 000000000000..85e3ec56653c
--- /dev/null
+++ b/src/tools/clippy/src/docs/undropped_manually_drops.txt
@@ -0,0 +1,22 @@
+### What it does
+Prevents the safe `std::mem::drop` function from being called on `std::mem::ManuallyDrop`.
+
+### Why is this bad?
+The safe `drop` function does not drop the inner value of a `ManuallyDrop`.
+
+### Known problems
+Does not catch cases if the user binds `std::mem::drop`
+to a different name and calls it that way.
+
+### Example
+```
+struct S;
+drop(std::mem::ManuallyDrop::new(S));
+```
+Use instead:
+```
+struct S;
+unsafe {
+    std::mem::ManuallyDrop::drop(&mut std::mem::ManuallyDrop::new(S));
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unicode_not_nfc.txt b/src/tools/clippy/src/docs/unicode_not_nfc.txt
new file mode 100644
index 000000000000..c660c51dadb2
--- /dev/null
+++ b/src/tools/clippy/src/docs/unicode_not_nfc.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for string literals that contain Unicode in a form
+that is not equal to its
+[NFC-recomposition](http://www.unicode.org/reports/tr15/#Norm_Forms).
+
+### Why is this bad?
+If such a string is compared to another, the results
+may be surprising.
+
+### Example
+You may not see it, but "à"" and "à"" aren't the same string. The
+former when escaped is actually `"a\u{300}"` while the latter is `"\u{e0}"`.
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unimplemented.txt b/src/tools/clippy/src/docs/unimplemented.txt
new file mode 100644
index 000000000000..7095594fb2e7
--- /dev/null
+++ b/src/tools/clippy/src/docs/unimplemented.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for usage of `unimplemented!`.
+
+### Why is this bad?
+This macro should not be present in production code
+
+### Example
+```
+unimplemented!();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/uninit_assumed_init.txt b/src/tools/clippy/src/docs/uninit_assumed_init.txt
new file mode 100644
index 000000000000..cca24093d40d
--- /dev/null
+++ b/src/tools/clippy/src/docs/uninit_assumed_init.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for `MaybeUninit::uninit().assume_init()`.
+
+### Why is this bad?
+For most types, this is undefined behavior.
+
+### Known problems
+For now, we accept empty tuples and tuples / arrays
+of `MaybeUninit`. There may be other types that allow uninitialized
+data, but those are not yet rigorously defined.
+
+### Example
+```
+// Beware the UB
+use std::mem::MaybeUninit;
+
+let _: usize = unsafe { MaybeUninit::uninit().assume_init() };
+```
+
+Note that the following is OK:
+
+```
+use std::mem::MaybeUninit;
+
+let _: [MaybeUninit<bool>; 5] = unsafe {
+    MaybeUninit::uninit().assume_init()
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/uninit_vec.txt b/src/tools/clippy/src/docs/uninit_vec.txt
new file mode 100644
index 000000000000..cd50afe78f6f
--- /dev/null
+++ b/src/tools/clippy/src/docs/uninit_vec.txt
@@ -0,0 +1,41 @@
+### What it does
+Checks for `set_len()` call that creates `Vec` with uninitialized elements.
+This is commonly caused by calling `set_len()` right after allocating or
+reserving a buffer with `new()`, `default()`, `with_capacity()`, or `reserve()`.
+
+### Why is this bad?
+It creates a `Vec` with uninitialized data, which leads to
+undefined behavior with most safe operations. Notably, uninitialized
+`Vec<u8>` must not be used with generic `Read`.
+
+Moreover, calling `set_len()` on a `Vec` created with `new()` or `default()`
+creates out-of-bound values that lead to heap memory corruption when used.
+
+### Known Problems
+This lint only checks directly adjacent statements.
+
+### Example
+```
+let mut vec: Vec<u8> = Vec::with_capacity(1000);
+unsafe { vec.set_len(1000); }
+reader.read(&mut vec); // undefined behavior!
+```
+
+### How to fix?
+1. Use an initialized buffer:
+   ```rust,ignore
+   let mut vec: Vec<u8> = vec![0; 1000];
+   reader.read(&mut vec);
+   ```
+2. Wrap the content in `MaybeUninit`:
+   ```rust,ignore
+   let mut vec: Vec<MaybeUninit<T>> = Vec::with_capacity(1000);
+   vec.set_len(1000);  // `MaybeUninit` can be uninitialized
+   ```
+3. If you are on 1.60.0 or later, `Vec::spare_capacity_mut()` is available:
+   ```rust,ignore
+   let mut vec: Vec<u8> = Vec::with_capacity(1000);
+   let remaining = vec.spare_capacity_mut();  // `&mut [MaybeUninit<u8>]`
+   // perform initialization with `remaining`
+   vec.set_len(...);  // Safe to call `set_len()` on initialized part
+   ```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unit_arg.txt b/src/tools/clippy/src/docs/unit_arg.txt
new file mode 100644
index 000000000000..eb83403bb275
--- /dev/null
+++ b/src/tools/clippy/src/docs/unit_arg.txt
@@ -0,0 +1,14 @@
+### What it does
+Checks for passing a unit value as an argument to a function without using a
+unit literal (`()`).
+
+### Why is this bad?
+This is likely the result of an accidental semicolon.
+
+### Example
+```
+foo({
+    let a = bar();
+    baz(a);
+})
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unit_cmp.txt b/src/tools/clippy/src/docs/unit_cmp.txt
new file mode 100644
index 000000000000..6f3d62010dc5
--- /dev/null
+++ b/src/tools/clippy/src/docs/unit_cmp.txt
@@ -0,0 +1,33 @@
+### What it does
+Checks for comparisons to unit. This includes all binary
+comparisons (like `==` and `<`) and asserts.
+
+### Why is this bad?
+Unit is always equal to itself, and thus is just a
+clumsily written constant. Mostly this happens when someone accidentally
+adds semicolons at the end of the operands.
+
+### Example
+```
+if {
+    foo();
+} == {
+    bar();
+} {
+    baz();
+}
+```
+is equal to
+```
+{
+    foo();
+    bar();
+    baz();
+}
+```
+
+For asserts:
+```
+assert_eq!({ foo(); }, { bar(); });
+```
+will always succeed
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unit_hash.txt b/src/tools/clippy/src/docs/unit_hash.txt
new file mode 100644
index 000000000000..a22d2994602a
--- /dev/null
+++ b/src/tools/clippy/src/docs/unit_hash.txt
@@ -0,0 +1,20 @@
+### What it does
+Detects `().hash(_)`.
+
+### Why is this bad?
+Hashing a unit value doesn't do anything as the implementation of `Hash` for `()` is a no-op.
+
+### Example
+```
+match my_enum {
+	Empty => ().hash(&mut state),
+	WithValue(x) => x.hash(&mut state),
+}
+```
+Use instead:
+```
+match my_enum {
+	Empty => 0_u8.hash(&mut state),
+	WithValue(x) => x.hash(&mut state),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unit_return_expecting_ord.txt b/src/tools/clippy/src/docs/unit_return_expecting_ord.txt
new file mode 100644
index 000000000000..781feac5afcf
--- /dev/null
+++ b/src/tools/clippy/src/docs/unit_return_expecting_ord.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for functions that expect closures of type
+Fn(...) -> Ord where the implemented closure returns the unit type.
+The lint also suggests to remove the semi-colon at the end of the statement if present.
+
+### Why is this bad?
+Likely, returning the unit type is unintentional, and
+could simply be caused by an extra semi-colon. Since () implements Ord
+it doesn't cause a compilation error.
+This is the same reasoning behind the unit_cmp lint.
+
+### Known problems
+If returning unit is intentional, then there is no
+way of specifying this without triggering needless_return lint
+
+### Example
+```
+let mut twins = vec!((1, 1), (2, 2));
+twins.sort_by_key(|x| { x.1; });
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_cast.txt b/src/tools/clippy/src/docs/unnecessary_cast.txt
new file mode 100644
index 000000000000..603f2606099c
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_cast.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for casts to the same type, casts of int literals to integer types
+and casts of float literals to float types.
+
+### Why is this bad?
+It's just unnecessary.
+
+### Example
+```
+let _ = 2i32 as i32;
+let _ = 0.5 as f32;
+```
+
+Better:
+
+```
+let _ = 2_i32;
+let _ = 0.5_f32;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_filter_map.txt b/src/tools/clippy/src/docs/unnecessary_filter_map.txt
new file mode 100644
index 000000000000..b19341ecf660
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_filter_map.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for `filter_map` calls that could be replaced by `filter` or `map`.
+More specifically it checks if the closure provided is only performing one of the
+filter or map operations and suggests the appropriate option.
+
+### Why is this bad?
+Complexity. The intent is also clearer if only a single
+operation is being performed.
+
+### Example
+```
+let _ = (0..3).filter_map(|x| if x > 2 { Some(x) } else { None });
+
+// As there is no transformation of the argument this could be written as:
+let _ = (0..3).filter(|&x| x > 2);
+```
+
+```
+let _ = (0..4).filter_map(|x| Some(x + 1));
+
+// As there is no conditional check on the argument this could be written as:
+let _ = (0..4).map(|x| x + 1);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_find_map.txt b/src/tools/clippy/src/docs/unnecessary_find_map.txt
new file mode 100644
index 000000000000..f9444dc48ad6
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_find_map.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for `find_map` calls that could be replaced by `find` or `map`. More
+specifically it checks if the closure provided is only performing one of the
+find or map operations and suggests the appropriate option.
+
+### Why is this bad?
+Complexity. The intent is also clearer if only a single
+operation is being performed.
+
+### Example
+```
+let _ = (0..3).find_map(|x| if x > 2 { Some(x) } else { None });
+
+// As there is no transformation of the argument this could be written as:
+let _ = (0..3).find(|&x| x > 2);
+```
+
+```
+let _ = (0..4).find_map(|x| Some(x + 1));
+
+// As there is no conditional check on the argument this could be written as:
+let _ = (0..4).map(|x| x + 1).next();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_fold.txt b/src/tools/clippy/src/docs/unnecessary_fold.txt
new file mode 100644
index 000000000000..e1b0e65f5197
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_fold.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for using `fold` when a more succinct alternative exists.
+Specifically, this checks for `fold`s which could be replaced by `any`, `all`,
+`sum` or `product`.
+
+### Why is this bad?
+Readability.
+
+### Example
+```
+(0..3).fold(false, |acc, x| acc || x > 2);
+```
+
+Use instead:
+```
+(0..3).any(|x| x > 2);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_join.txt b/src/tools/clippy/src/docs/unnecessary_join.txt
new file mode 100644
index 000000000000..ee4e78601f84
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_join.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for use of `.collect::<Vec<String>>().join("")` on iterators.
+
+### Why is this bad?
+`.collect::<String>()` is more concise and might be more performant
+
+### Example
+```
+let vector = vec!["hello",  "world"];
+let output = vector.iter().map(|item| item.to_uppercase()).collect::<Vec<String>>().join("");
+println!("{}", output);
+```
+The correct use would be:
+```
+let vector = vec!["hello",  "world"];
+let output = vector.iter().map(|item| item.to_uppercase()).collect::<String>();
+println!("{}", output);
+```
+### Known problems
+While `.collect::<String>()` is sometimes more performant, there are cases where
+using `.collect::<String>()` over `.collect::<Vec<String>>().join("")`
+will prevent loop unrolling and will result in a negative performance impact.
+
+Additionally, differences have been observed between aarch64 and x86_64 assembly output,
+with aarch64 tending to producing faster assembly in more cases when using `.collect::<String>()`
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_lazy_evaluations.txt b/src/tools/clippy/src/docs/unnecessary_lazy_evaluations.txt
new file mode 100644
index 000000000000..208188ce971a
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_lazy_evaluations.txt
@@ -0,0 +1,32 @@
+### What it does
+As the counterpart to `or_fun_call`, this lint looks for unnecessary
+lazily evaluated closures on `Option` and `Result`.
+
+This lint suggests changing the following functions, when eager evaluation results in
+simpler code:
+ - `unwrap_or_else` to `unwrap_or`
+ - `and_then` to `and`
+ - `or_else` to `or`
+ - `get_or_insert_with` to `get_or_insert`
+ - `ok_or_else` to `ok_or`
+
+### Why is this bad?
+Using eager evaluation is shorter and simpler in some cases.
+
+### Known problems
+It is possible, but not recommended for `Deref` and `Index` to have
+side effects. Eagerly evaluating them can change the semantics of the program.
+
+### Example
+```
+// example code where clippy issues a warning
+let opt: Option<u32> = None;
+
+opt.unwrap_or_else(|| 42);
+```
+Use instead:
+```
+let opt: Option<u32> = None;
+
+opt.unwrap_or(42);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_mut_passed.txt b/src/tools/clippy/src/docs/unnecessary_mut_passed.txt
new file mode 100644
index 000000000000..2f8bdd113dfd
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_mut_passed.txt
@@ -0,0 +1,17 @@
+### What it does
+Detects passing a mutable reference to a function that only
+requires an immutable reference.
+
+### Why is this bad?
+The mutable reference rules out all other references to
+the value. Also the code misleads about the intent of the call site.
+
+### Example
+```
+vec.push(&mut value);
+```
+
+Use instead:
+```
+vec.push(&value);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_operation.txt b/src/tools/clippy/src/docs/unnecessary_operation.txt
new file mode 100644
index 000000000000..7f455e264cb3
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_operation.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for expression statements that can be reduced to a
+sub-expression.
+
+### Why is this bad?
+Expressions by themselves often have no side-effects.
+Having such expressions reduces readability.
+
+### Example
+```
+compute_array()[0];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_owned_empty_strings.txt b/src/tools/clippy/src/docs/unnecessary_owned_empty_strings.txt
new file mode 100644
index 000000000000..8cd9fba603e0
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_owned_empty_strings.txt
@@ -0,0 +1,16 @@
+### What it does
+
+Detects cases of owned empty strings being passed as an argument to a function expecting `&str`
+
+### Why is this bad?
+
+This results in longer and less readable code
+
+### Example
+```
+vec!["1", "2", "3"].join(&String::new());
+```
+Use instead:
+```
+vec!["1", "2", "3"].join("");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_self_imports.txt b/src/tools/clippy/src/docs/unnecessary_self_imports.txt
new file mode 100644
index 000000000000..b909cd5a76da
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_self_imports.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for imports ending in `::{self}`.
+
+### Why is this bad?
+In most cases, this can be written much more cleanly by omitting `::{self}`.
+
+### Known problems
+Removing `::{self}` will cause any non-module items at the same path to also be imported.
+This might cause a naming conflict (https://github.com/rust-lang/rustfmt/issues/3568). This lint makes no attempt
+to detect this scenario and that is why it is a restriction lint.
+
+### Example
+```
+use std::io::{self};
+```
+Use instead:
+```
+use std::io;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_sort_by.txt b/src/tools/clippy/src/docs/unnecessary_sort_by.txt
new file mode 100644
index 000000000000..6913b62c48eb
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_sort_by.txt
@@ -0,0 +1,21 @@
+### What it does
+Detects uses of `Vec::sort_by` passing in a closure
+which compares the two arguments, either directly or indirectly.
+
+### Why is this bad?
+It is more clear to use `Vec::sort_by_key` (or `Vec::sort` if
+possible) than to use `Vec::sort_by` and a more complicated
+closure.
+
+### Known problems
+If the suggested `Vec::sort_by_key` uses Reverse and it isn't already
+imported by a use statement, then it will need to be added manually.
+
+### Example
+```
+vec.sort_by(|a, b| a.foo().cmp(&b.foo()));
+```
+Use instead:
+```
+vec.sort_by_key(|a| a.foo());
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_to_owned.txt b/src/tools/clippy/src/docs/unnecessary_to_owned.txt
new file mode 100644
index 000000000000..5d4213bdaf89
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_to_owned.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for unnecessary calls to [`ToOwned::to_owned`](https://doc.rust-lang.org/std/borrow/trait.ToOwned.html#tymethod.to_owned)
+and other `to_owned`-like functions.
+
+### Why is this bad?
+The unnecessary calls result in useless allocations.
+
+### Known problems
+`unnecessary_to_owned` can falsely trigger if `IntoIterator::into_iter` is applied to an
+owned copy of a resource and the resource is later used mutably. See
+[#8148](https://github.com/rust-lang/rust-clippy/issues/8148).
+
+### Example
+```
+let path = std::path::Path::new("x");
+foo(&path.to_string_lossy().to_string());
+fn foo(s: &str) {}
+```
+Use instead:
+```
+let path = std::path::Path::new("x");
+foo(&path.to_string_lossy());
+fn foo(s: &str) {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_unwrap.txt b/src/tools/clippy/src/docs/unnecessary_unwrap.txt
new file mode 100644
index 000000000000..50ae845bb44f
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_unwrap.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for calls of `unwrap[_err]()` that cannot fail.
+
+### Why is this bad?
+Using `if let` or `match` is more idiomatic.
+
+### Example
+```
+if option.is_some() {
+    do_something_with(option.unwrap())
+}
+```
+
+Could be written:
+
+```
+if let Some(value) = option {
+    do_something_with(value)
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnecessary_wraps.txt b/src/tools/clippy/src/docs/unnecessary_wraps.txt
new file mode 100644
index 000000000000..c0a23d492889
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnecessary_wraps.txt
@@ -0,0 +1,36 @@
+### What it does
+Checks for private functions that only return `Ok` or `Some`.
+
+### Why is this bad?
+It is not meaningful to wrap values when no `None` or `Err` is returned.
+
+### Known problems
+There can be false positives if the function signature is designed to
+fit some external requirement.
+
+### Example
+```
+fn get_cool_number(a: bool, b: bool) -> Option<i32> {
+    if a && b {
+        return Some(50);
+    }
+    if a {
+        Some(0)
+    } else {
+        Some(10)
+    }
+}
+```
+Use instead:
+```
+fn get_cool_number(a: bool, b: bool) -> i32 {
+    if a && b {
+        return 50;
+    }
+    if a {
+        0
+    } else {
+        10
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unneeded_field_pattern.txt b/src/tools/clippy/src/docs/unneeded_field_pattern.txt
new file mode 100644
index 000000000000..3cd00a0f3e38
--- /dev/null
+++ b/src/tools/clippy/src/docs/unneeded_field_pattern.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for structure field patterns bound to wildcards.
+
+### Why is this bad?
+Using `..` instead is shorter and leaves the focus on
+the fields that are actually bound.
+
+### Example
+```
+let f = Foo { a: 0, b: 0, c: 0 };
+
+match f {
+    Foo { a: _, b: 0, .. } => {},
+    Foo { a: _, b: _, c: _ } => {},
+}
+```
+
+Use instead:
+```
+let f = Foo { a: 0, b: 0, c: 0 };
+
+match f {
+    Foo { b: 0, .. } => {},
+    Foo { .. } => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unneeded_wildcard_pattern.txt b/src/tools/clippy/src/docs/unneeded_wildcard_pattern.txt
new file mode 100644
index 000000000000..817061efd162
--- /dev/null
+++ b/src/tools/clippy/src/docs/unneeded_wildcard_pattern.txt
@@ -0,0 +1,28 @@
+### What it does
+Checks for tuple patterns with a wildcard
+pattern (`_`) is next to a rest pattern (`..`).
+
+_NOTE_: While `_, ..` means there is at least one element left, `..`
+means there are 0 or more elements left. This can make a difference
+when refactoring, but shouldn't result in errors in the refactored code,
+since the wildcard pattern isn't used anyway.
+
+### Why is this bad?
+The wildcard pattern is unneeded as the rest pattern
+can match that element as well.
+
+### Example
+```
+match t {
+    TupleStruct(0, .., _) => (),
+    _ => (),
+}
+```
+
+Use instead:
+```
+match t {
+    TupleStruct(0, ..) => (),
+    _ => (),
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unnested_or_patterns.txt b/src/tools/clippy/src/docs/unnested_or_patterns.txt
new file mode 100644
index 000000000000..49c45d4ee5e9
--- /dev/null
+++ b/src/tools/clippy/src/docs/unnested_or_patterns.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for unnested or-patterns, e.g., `Some(0) | Some(2)` and
+suggests replacing the pattern with a nested one, `Some(0 | 2)`.
+
+Another way to think of this is that it rewrites patterns in
+*disjunctive normal form (DNF)* into *conjunctive normal form (CNF)*.
+
+### Why is this bad?
+In the example above, `Some` is repeated, which unnecessarily complicates the pattern.
+
+### Example
+```
+fn main() {
+    if let Some(0) | Some(2) = Some(0) {}
+}
+```
+Use instead:
+```
+fn main() {
+    if let Some(0 | 2) = Some(0) {}
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unreachable.txt b/src/tools/clippy/src/docs/unreachable.txt
new file mode 100644
index 000000000000..10469ca77454
--- /dev/null
+++ b/src/tools/clippy/src/docs/unreachable.txt
@@ -0,0 +1,10 @@
+### What it does
+Checks for usage of `unreachable!`.
+
+### Why is this bad?
+This macro can cause code to panic
+
+### Example
+```
+unreachable!();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unreadable_literal.txt b/src/tools/clippy/src/docs/unreadable_literal.txt
new file mode 100644
index 000000000000..e168f90a84c1
--- /dev/null
+++ b/src/tools/clippy/src/docs/unreadable_literal.txt
@@ -0,0 +1,16 @@
+### What it does
+Warns if a long integral or floating-point constant does
+not contain underscores.
+
+### Why is this bad?
+Reading long numbers is difficult without separators.
+
+### Example
+```
+61864918973511
+```
+
+Use instead:
+```
+61_864_918_973_511
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unsafe_derive_deserialize.txt b/src/tools/clippy/src/docs/unsafe_derive_deserialize.txt
new file mode 100644
index 000000000000..f56c48044f4f
--- /dev/null
+++ b/src/tools/clippy/src/docs/unsafe_derive_deserialize.txt
@@ -0,0 +1,27 @@
+### What it does
+Checks for deriving `serde::Deserialize` on a type that
+has methods using `unsafe`.
+
+### Why is this bad?
+Deriving `serde::Deserialize` will create a constructor
+that may violate invariants hold by another constructor.
+
+### Example
+```
+use serde::Deserialize;
+
+#[derive(Deserialize)]
+pub struct Foo {
+    // ..
+}
+
+impl Foo {
+    pub fn new() -> Self {
+        // setup here ..
+    }
+
+    pub unsafe fn parts() -> (&str, &str) {
+        // assumes invariants hold
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unsafe_removed_from_name.txt b/src/tools/clippy/src/docs/unsafe_removed_from_name.txt
new file mode 100644
index 000000000000..6f55c1815dd6
--- /dev/null
+++ b/src/tools/clippy/src/docs/unsafe_removed_from_name.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for imports that remove "unsafe" from an item's
+name.
+
+### Why is this bad?
+Renaming makes it less clear which traits and
+structures are unsafe.
+
+### Example
+```
+use std::cell::{UnsafeCell as TotallySafeCell};
+
+extern crate crossbeam;
+use crossbeam::{spawn_unsafe as spawn};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unseparated_literal_suffix.txt b/src/tools/clippy/src/docs/unseparated_literal_suffix.txt
new file mode 100644
index 000000000000..d80248e34d0c
--- /dev/null
+++ b/src/tools/clippy/src/docs/unseparated_literal_suffix.txt
@@ -0,0 +1,18 @@
+### What it does
+Warns if literal suffixes are not separated by an
+underscore.
+To enforce unseparated literal suffix style,
+see the `separated_literal_suffix` lint.
+
+### Why is this bad?
+Suffix style should be consistent.
+
+### Example
+```
+123832i32
+```
+
+Use instead:
+```
+123832_i32
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unsound_collection_transmute.txt b/src/tools/clippy/src/docs/unsound_collection_transmute.txt
new file mode 100644
index 000000000000..29db9258e83f
--- /dev/null
+++ b/src/tools/clippy/src/docs/unsound_collection_transmute.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for transmutes between collections whose
+types have different ABI, size or alignment.
+
+### Why is this bad?
+This is undefined behavior.
+
+### Known problems
+Currently, we cannot know whether a type is a
+collection, so we just lint the ones that come with `std`.
+
+### Example
+```
+// different size, therefore likely out-of-bounds memory access
+// You absolutely do not want this in your code!
+unsafe {
+    std::mem::transmute::<_, Vec<u32>>(vec![2_u16])
+};
+```
+
+You must always iterate, map and collect the values:
+
+```
+vec![2_u16].into_iter().map(u32::from).collect::<Vec<_>>();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unused_async.txt b/src/tools/clippy/src/docs/unused_async.txt
new file mode 100644
index 000000000000..26def11aa17a
--- /dev/null
+++ b/src/tools/clippy/src/docs/unused_async.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for functions that are declared `async` but have no `.await`s inside of them.
+
+### Why is this bad?
+Async functions with no async code create overhead, both mentally and computationally.
+Callers of async methods either need to be calling from an async function themselves or run it on an executor, both of which
+causes runtime overhead and hassle for the caller.
+
+### Example
+```
+async fn get_random_number() -> i64 {
+    4 // Chosen by fair dice roll. Guaranteed to be random.
+}
+let number_future = get_random_number();
+```
+
+Use instead:
+```
+fn get_random_number_improved() -> i64 {
+    4 // Chosen by fair dice roll. Guaranteed to be random.
+}
+let number_future = async { get_random_number_improved() };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unused_io_amount.txt b/src/tools/clippy/src/docs/unused_io_amount.txt
new file mode 100644
index 000000000000..fbc4c299c7bb
--- /dev/null
+++ b/src/tools/clippy/src/docs/unused_io_amount.txt
@@ -0,0 +1,31 @@
+### What it does
+Checks for unused written/read amount.
+
+### Why is this bad?
+`io::Write::write(_vectored)` and
+`io::Read::read(_vectored)` are not guaranteed to
+process the entire buffer. They return how many bytes were processed, which
+might be smaller
+than a given buffer's length. If you don't need to deal with
+partial-write/read, use
+`write_all`/`read_exact` instead.
+
+When working with asynchronous code (either with the `futures`
+crate or with `tokio`), a similar issue exists for
+`AsyncWriteExt::write()` and `AsyncReadExt::read()` : these
+functions are also not guaranteed to process the entire
+buffer.  Your code should either handle partial-writes/reads, or
+call the `write_all`/`read_exact` methods on those traits instead.
+
+### Known problems
+Detects only common patterns.
+
+### Examples
+```
+use std::io;
+fn foo<W: io::Write>(w: &mut W) -> io::Result<()> {
+    // must be `w.write_all(b"foo")?;`
+    w.write(b"foo")?;
+    Ok(())
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unused_peekable.txt b/src/tools/clippy/src/docs/unused_peekable.txt
new file mode 100644
index 000000000000..268de1ce3bec
--- /dev/null
+++ b/src/tools/clippy/src/docs/unused_peekable.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for the creation of a `peekable` iterator that is never `.peek()`ed
+
+### Why is this bad?
+Creating a peekable iterator without using any of its methods is likely a mistake,
+or just a leftover after a refactor.
+
+### Example
+```
+let collection = vec![1, 2, 3];
+let iter = collection.iter().peekable();
+
+for item in iter {
+    // ...
+}
+```
+
+Use instead:
+```
+let collection = vec![1, 2, 3];
+let iter = collection.iter();
+
+for item in iter {
+    // ...
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unused_rounding.txt b/src/tools/clippy/src/docs/unused_rounding.txt
new file mode 100644
index 000000000000..70947aceee77
--- /dev/null
+++ b/src/tools/clippy/src/docs/unused_rounding.txt
@@ -0,0 +1,17 @@
+### What it does
+
+Detects cases where a whole-number literal float is being rounded, using
+the `floor`, `ceil`, or `round` methods.
+
+### Why is this bad?
+
+This is unnecessary and confusing to the reader. Doing this is probably a mistake.
+
+### Example
+```
+let x = 1f32.ceil();
+```
+Use instead:
+```
+let x = 1f32;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unused_self.txt b/src/tools/clippy/src/docs/unused_self.txt
new file mode 100644
index 000000000000..a8d0fc759895
--- /dev/null
+++ b/src/tools/clippy/src/docs/unused_self.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks methods that contain a `self` argument but don't use it
+
+### Why is this bad?
+It may be clearer to define the method as an associated function instead
+of an instance method if it doesn't require `self`.
+
+### Example
+```
+struct A;
+impl A {
+    fn method(&self) {}
+}
+```
+
+Could be written:
+
+```
+struct A;
+impl A {
+    fn method() {}
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unused_unit.txt b/src/tools/clippy/src/docs/unused_unit.txt
new file mode 100644
index 000000000000..48d16ca65523
--- /dev/null
+++ b/src/tools/clippy/src/docs/unused_unit.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for unit (`()`) expressions that can be removed.
+
+### Why is this bad?
+Such expressions add no value, but can make the code
+less readable. Depending on formatting they can make a `break` or `return`
+statement look like a function call.
+
+### Example
+```
+fn return_unit() -> () {
+    ()
+}
+```
+is equivalent to
+```
+fn return_unit() {}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unusual_byte_groupings.txt b/src/tools/clippy/src/docs/unusual_byte_groupings.txt
new file mode 100644
index 000000000000..9a1f132a6112
--- /dev/null
+++ b/src/tools/clippy/src/docs/unusual_byte_groupings.txt
@@ -0,0 +1,12 @@
+### What it does
+Warns if hexadecimal or binary literals are not grouped
+by nibble or byte.
+
+### Why is this bad?
+Negatively impacts readability.
+
+### Example
+```
+let x: u32 = 0xFFF_FFF;
+let y: u8 = 0b01_011_101;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unwrap_in_result.txt b/src/tools/clippy/src/docs/unwrap_in_result.txt
new file mode 100644
index 000000000000..7497dd863d35
--- /dev/null
+++ b/src/tools/clippy/src/docs/unwrap_in_result.txt
@@ -0,0 +1,39 @@
+### What it does
+Checks for functions of type `Result` that contain `expect()` or `unwrap()`
+
+### Why is this bad?
+These functions promote recoverable errors to non-recoverable errors which may be undesirable in code bases which wish to avoid panics.
+
+### Known problems
+This can cause false positives in functions that handle both recoverable and non recoverable errors.
+
+### Example
+Before:
+```
+fn divisible_by_3(i_str: String) -> Result<(), String> {
+    let i = i_str
+        .parse::<i32>()
+        .expect("cannot divide the input by three");
+
+    if i % 3 != 0 {
+        Err("Number is not divisible by 3")?
+    }
+
+    Ok(())
+}
+```
+
+After:
+```
+fn divisible_by_3(i_str: String) -> Result<(), String> {
+    let i = i_str
+        .parse::<i32>()
+        .map_err(|e| format!("cannot divide the input by three: {}", e))?;
+
+    if i % 3 != 0 {
+        Err("Number is not divisible by 3")?
+    }
+
+    Ok(())
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unwrap_or_else_default.txt b/src/tools/clippy/src/docs/unwrap_or_else_default.txt
new file mode 100644
index 000000000000..34b4cf088581
--- /dev/null
+++ b/src/tools/clippy/src/docs/unwrap_or_else_default.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for usages of `_.unwrap_or_else(Default::default)` on `Option` and
+`Result` values.
+
+### Why is this bad?
+Readability, these can be written as `_.unwrap_or_default`, which is
+simpler and more concise.
+
+### Examples
+```
+x.unwrap_or_else(Default::default);
+x.unwrap_or_else(u32::default);
+```
+
+Use instead:
+```
+x.unwrap_or_default();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/unwrap_used.txt b/src/tools/clippy/src/docs/unwrap_used.txt
new file mode 100644
index 000000000000..9b4713df515d
--- /dev/null
+++ b/src/tools/clippy/src/docs/unwrap_used.txt
@@ -0,0 +1,37 @@
+### What it does
+Checks for `.unwrap()` or `.unwrap_err()` calls on `Result`s and `.unwrap()` call on `Option`s.
+
+### Why is this bad?
+It is better to handle the `None` or `Err` case,
+or at least call `.expect(_)` with a more helpful message. Still, for a lot of
+quick-and-dirty code, `unwrap` is a good choice, which is why this lint is
+`Allow` by default.
+
+`result.unwrap()` will let the thread panic on `Err` values.
+Normally, you want to implement more sophisticated error handling,
+and propagate errors upwards with `?` operator.
+
+Even if you want to panic on errors, not all `Error`s implement good
+messages on display. Therefore, it may be beneficial to look at the places
+where they may get displayed. Activate this lint to do just that.
+
+### Examples
+```
+option.unwrap();
+result.unwrap();
+```
+
+Use instead:
+```
+option.expect("more helpful message");
+result.expect("more helpful message");
+```
+
+If [expect_used](#expect_used) is enabled, instead:
+```
+option?;
+
+// or
+
+result?;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/upper_case_acronyms.txt b/src/tools/clippy/src/docs/upper_case_acronyms.txt
new file mode 100644
index 000000000000..a1e39c7e10c6
--- /dev/null
+++ b/src/tools/clippy/src/docs/upper_case_acronyms.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for fully capitalized names and optionally names containing a capitalized acronym.
+
+### Why is this bad?
+In CamelCase, acronyms count as one word.
+See [naming conventions](https://rust-lang.github.io/api-guidelines/naming.html#casing-conforms-to-rfc-430-c-case)
+for more.
+
+By default, the lint only triggers on fully-capitalized names.
+You can use the `upper-case-acronyms-aggressive: true` config option to enable linting
+on all camel case names
+
+### Known problems
+When two acronyms are contiguous, the lint can't tell where
+the first acronym ends and the second starts, so it suggests to lowercase all of
+the letters in the second acronym.
+
+### Example
+```
+struct HTTPResponse;
+```
+Use instead:
+```
+struct HttpResponse;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/use_debug.txt b/src/tools/clippy/src/docs/use_debug.txt
new file mode 100644
index 000000000000..94d4a6fd29ae
--- /dev/null
+++ b/src/tools/clippy/src/docs/use_debug.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for use of `Debug` formatting. The purpose of this
+lint is to catch debugging remnants.
+
+### Why is this bad?
+The purpose of the `Debug` trait is to facilitate
+debugging Rust code. It should not be used in user-facing output.
+
+### Example
+```
+println!("{:?}", foo);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/use_self.txt b/src/tools/clippy/src/docs/use_self.txt
new file mode 100644
index 000000000000..bd37ed1e0025
--- /dev/null
+++ b/src/tools/clippy/src/docs/use_self.txt
@@ -0,0 +1,31 @@
+### What it does
+Checks for unnecessary repetition of structure name when a
+replacement with `Self` is applicable.
+
+### Why is this bad?
+Unnecessary repetition. Mixed use of `Self` and struct
+name
+feels inconsistent.
+
+### Known problems
+- Unaddressed false negative in fn bodies of trait implementations
+- False positive with associated types in traits (#4140)
+
+### Example
+```
+struct Foo;
+impl Foo {
+    fn new() -> Foo {
+        Foo {}
+    }
+}
+```
+could be
+```
+struct Foo;
+impl Foo {
+    fn new() -> Self {
+        Self {}
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/used_underscore_binding.txt b/src/tools/clippy/src/docs/used_underscore_binding.txt
new file mode 100644
index 000000000000..ed67c41eb0db
--- /dev/null
+++ b/src/tools/clippy/src/docs/used_underscore_binding.txt
@@ -0,0 +1,19 @@
+### What it does
+Checks for the use of bindings with a single leading
+underscore.
+
+### Why is this bad?
+A single leading underscore is usually used to indicate
+that a binding will not be used. Using such a binding breaks this
+expectation.
+
+### Known problems
+The lint does not work properly with desugaring and
+macro, it has been allowed in the mean time.
+
+### Example
+```
+let _x = 0;
+let y = _x + 1; // Here we are using `_x`, even though it has a leading
+                // underscore. We should rename `_x` to `x`
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_asref.txt b/src/tools/clippy/src/docs/useless_asref.txt
new file mode 100644
index 000000000000..f777cd3775ed
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_asref.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for usage of `.as_ref()` or `.as_mut()` where the
+types before and after the call are the same.
+
+### Why is this bad?
+The call is unnecessary.
+
+### Example
+```
+let x: &[i32] = &[1, 2, 3, 4, 5];
+do_stuff(x.as_ref());
+```
+The correct use would be:
+```
+let x: &[i32] = &[1, 2, 3, 4, 5];
+do_stuff(x);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_attribute.txt b/src/tools/clippy/src/docs/useless_attribute.txt
new file mode 100644
index 000000000000..e02d4c907898
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_attribute.txt
@@ -0,0 +1,36 @@
+### What it does
+Checks for `extern crate` and `use` items annotated with
+lint attributes.
+
+This lint permits lint attributes for lints emitted on the items themself.
+For `use` items these lints are:
+* deprecated
+* unreachable_pub
+* unused_imports
+* clippy::enum_glob_use
+* clippy::macro_use_imports
+* clippy::wildcard_imports
+
+For `extern crate` items these lints are:
+* `unused_imports` on items with `#[macro_use]`
+
+### Why is this bad?
+Lint attributes have no effect on crate imports. Most
+likely a `!` was forgotten.
+
+### Example
+```
+#[deny(dead_code)]
+extern crate foo;
+#[forbid(dead_code)]
+use foo::bar;
+```
+
+Use instead:
+```
+#[allow(unused_imports)]
+use foo::baz;
+#[allow(unused_imports)]
+#[macro_use]
+extern crate baz;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_conversion.txt b/src/tools/clippy/src/docs/useless_conversion.txt
new file mode 100644
index 000000000000..06000a7ad98d
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_conversion.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for `Into`, `TryInto`, `From`, `TryFrom`, or `IntoIter` calls
+which uselessly convert to the same type.
+
+### Why is this bad?
+Redundant code.
+
+### Example
+```
+// format!() returns a `String`
+let s: String = format!("hello").into();
+```
+
+Use instead:
+```
+let s: String = format!("hello");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_format.txt b/src/tools/clippy/src/docs/useless_format.txt
new file mode 100644
index 000000000000..eb4819da1e95
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_format.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for the use of `format!("string literal with no
+argument")` and `format!("{}", foo)` where `foo` is a string.
+
+### Why is this bad?
+There is no point of doing that. `format!("foo")` can
+be replaced by `"foo".to_owned()` if you really need a `String`. The even
+worse `&format!("foo")` is often encountered in the wild. `format!("{}",
+foo)` can be replaced by `foo.clone()` if `foo: String` or `foo.to_owned()`
+if `foo: &str`.
+
+### Examples
+```
+let foo = "foo";
+format!("{}", foo);
+```
+
+Use instead:
+```
+let foo = "foo";
+foo.to_owned();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_let_if_seq.txt b/src/tools/clippy/src/docs/useless_let_if_seq.txt
new file mode 100644
index 000000000000..c6dcd57eb2e2
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_let_if_seq.txt
@@ -0,0 +1,39 @@
+### What it does
+Checks for variable declarations immediately followed by a
+conditional affectation.
+
+### Why is this bad?
+This is not idiomatic Rust.
+
+### Example
+```
+let foo;
+
+if bar() {
+    foo = 42;
+} else {
+    foo = 0;
+}
+
+let mut baz = None;
+
+if bar() {
+    baz = Some(42);
+}
+```
+
+should be written
+
+```
+let foo = if bar() {
+    42
+} else {
+    0
+};
+
+let baz = if bar() {
+    Some(42)
+} else {
+    None
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_transmute.txt b/src/tools/clippy/src/docs/useless_transmute.txt
new file mode 100644
index 000000000000..1d3a17588145
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_transmute.txt
@@ -0,0 +1,12 @@
+### What it does
+Checks for transmutes to the original type of the object
+and transmutes that could be a cast.
+
+### Why is this bad?
+Readability. The code tricks people into thinking that
+something complex is going on.
+
+### Example
+```
+core::intrinsics::transmute(t); // where the result type is the same as `t`'s
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/useless_vec.txt b/src/tools/clippy/src/docs/useless_vec.txt
new file mode 100644
index 000000000000..ee5afc99e4bf
--- /dev/null
+++ b/src/tools/clippy/src/docs/useless_vec.txt
@@ -0,0 +1,18 @@
+### What it does
+Checks for usage of `&vec![..]` when using `&[..]` would
+be possible.
+
+### Why is this bad?
+This is less efficient.
+
+### Example
+```
+fn foo(_x: &[u8]) {}
+
+foo(&vec![1, 2]);
+```
+
+Use instead:
+```
+foo(&[1, 2]);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/vec_box.txt b/src/tools/clippy/src/docs/vec_box.txt
new file mode 100644
index 000000000000..701b1c9ce9b9
--- /dev/null
+++ b/src/tools/clippy/src/docs/vec_box.txt
@@ -0,0 +1,26 @@
+### What it does
+Checks for use of `Vec<Box<T>>` where T: Sized anywhere in the code.
+Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
+
+### Why is this bad?
+`Vec` already keeps its contents in a separate area on
+the heap. So if you `Box` its contents, you just add another level of indirection.
+
+### Known problems
+Vec<Box<T: Sized>> makes sense if T is a large type (see [#3530](https://github.com/rust-lang/rust-clippy/issues/3530),
+1st comment).
+
+### Example
+```
+struct X {
+    values: Vec<Box<i32>>,
+}
+```
+
+Better:
+
+```
+struct X {
+    values: Vec<i32>,
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/vec_init_then_push.txt b/src/tools/clippy/src/docs/vec_init_then_push.txt
new file mode 100644
index 000000000000..445f2874796b
--- /dev/null
+++ b/src/tools/clippy/src/docs/vec_init_then_push.txt
@@ -0,0 +1,23 @@
+### What it does
+Checks for calls to `push` immediately after creating a new `Vec`.
+
+If the `Vec` is created using `with_capacity` this will only lint if the capacity is a
+constant and the number of pushes is greater than or equal to the initial capacity.
+
+If the `Vec` is extended after the initial sequence of pushes and it was default initialized
+then this will only lint after there were at least four pushes. This number may change in
+the future.
+
+### Why is this bad?
+The `vec![]` macro is both more performant and easier to read than
+multiple `push` calls.
+
+### Example
+```
+let mut v = Vec::new();
+v.push(0);
+```
+Use instead:
+```
+let v = vec![0];
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/vec_resize_to_zero.txt b/src/tools/clippy/src/docs/vec_resize_to_zero.txt
new file mode 100644
index 000000000000..0b92686772bb
--- /dev/null
+++ b/src/tools/clippy/src/docs/vec_resize_to_zero.txt
@@ -0,0 +1,15 @@
+### What it does
+Finds occurrences of `Vec::resize(0, an_int)`
+
+### Why is this bad?
+This is probably an argument inversion mistake.
+
+### Example
+```
+vec!(1, 2, 3, 4, 5).resize(0, 5)
+```
+
+Use instead:
+```
+vec!(1, 2, 3, 4, 5).clear()
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/verbose_bit_mask.txt b/src/tools/clippy/src/docs/verbose_bit_mask.txt
new file mode 100644
index 000000000000..87a84702925e
--- /dev/null
+++ b/src/tools/clippy/src/docs/verbose_bit_mask.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for bit masks that can be replaced by a call
+to `trailing_zeros`
+
+### Why is this bad?
+`x.trailing_zeros() > 4` is much clearer than `x & 15
+== 0`
+
+### Known problems
+llvm generates better code for `x & 15 == 0` on x86
+
+### Example
+```
+if x & 0b1111 == 0 { }
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/verbose_file_reads.txt b/src/tools/clippy/src/docs/verbose_file_reads.txt
new file mode 100644
index 000000000000..9703df423a57
--- /dev/null
+++ b/src/tools/clippy/src/docs/verbose_file_reads.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for use of File::read_to_end and File::read_to_string.
+
+### Why is this bad?
+`fs::{read, read_to_string}` provide the same functionality when `buf` is empty with fewer imports and no intermediate values.
+See also: [fs::read docs](https://doc.rust-lang.org/std/fs/fn.read.html), [fs::read_to_string docs](https://doc.rust-lang.org/std/fs/fn.read_to_string.html)
+
+### Example
+```
+let mut f = File::open("foo.txt").unwrap();
+let mut bytes = Vec::new();
+f.read_to_end(&mut bytes).unwrap();
+```
+Can be written more concisely as
+```
+let mut bytes = fs::read("foo.txt").unwrap();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/vtable_address_comparisons.txt b/src/tools/clippy/src/docs/vtable_address_comparisons.txt
new file mode 100644
index 000000000000..4a34e4ba78ef
--- /dev/null
+++ b/src/tools/clippy/src/docs/vtable_address_comparisons.txt
@@ -0,0 +1,17 @@
+### What it does
+Checks for comparisons with an address of a trait vtable.
+
+### Why is this bad?
+Comparing trait objects pointers compares an vtable addresses which
+are not guaranteed to be unique and could vary between different code generation units.
+Furthermore vtables for different types could have the same address after being merged
+together.
+
+### Example
+```
+let a: Rc<dyn Trait> = ...
+let b: Rc<dyn Trait> = ...
+if Rc::ptr_eq(&a, &b) {
+    ...
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/while_immutable_condition.txt b/src/tools/clippy/src/docs/while_immutable_condition.txt
new file mode 100644
index 000000000000..71800701f489
--- /dev/null
+++ b/src/tools/clippy/src/docs/while_immutable_condition.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks whether variables used within while loop condition
+can be (and are) mutated in the body.
+
+### Why is this bad?
+If the condition is unchanged, entering the body of the loop
+will lead to an infinite loop.
+
+### Known problems
+If the `while`-loop is in a closure, the check for mutation of the
+condition variables in the body can cause false negatives. For example when only `Upvar` `a` is
+in the condition and only `Upvar` `b` gets mutated in the body, the lint will not trigger.
+
+### Example
+```
+let i = 0;
+while i > 10 {
+    println!("let me loop forever!");
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/while_let_loop.txt b/src/tools/clippy/src/docs/while_let_loop.txt
new file mode 100644
index 000000000000..ab7bf60975ec
--- /dev/null
+++ b/src/tools/clippy/src/docs/while_let_loop.txt
@@ -0,0 +1,25 @@
+### What it does
+Detects `loop + match` combinations that are easier
+written as a `while let` loop.
+
+### Why is this bad?
+The `while let` loop is usually shorter and more
+readable.
+
+### Known problems
+Sometimes the wrong binding is displayed ([#383](https://github.com/rust-lang/rust-clippy/issues/383)).
+
+### Example
+```
+loop {
+    let x = match y {
+        Some(x) => x,
+        None => break,
+    };
+    // .. do something with x
+}
+// is easier written as
+while let Some(x) = y {
+    // .. do something with x
+};
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/while_let_on_iterator.txt b/src/tools/clippy/src/docs/while_let_on_iterator.txt
new file mode 100644
index 000000000000..af053c541199
--- /dev/null
+++ b/src/tools/clippy/src/docs/while_let_on_iterator.txt
@@ -0,0 +1,20 @@
+### What it does
+Checks for `while let` expressions on iterators.
+
+### Why is this bad?
+Readability. A simple `for` loop is shorter and conveys
+the intent better.
+
+### Example
+```
+while let Some(val) = iter.next() {
+    ..
+}
+```
+
+Use instead:
+```
+for val in &mut iter {
+    ..
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/wildcard_dependencies.txt b/src/tools/clippy/src/docs/wildcard_dependencies.txt
new file mode 100644
index 000000000000..2affaf9740d9
--- /dev/null
+++ b/src/tools/clippy/src/docs/wildcard_dependencies.txt
@@ -0,0 +1,13 @@
+### What it does
+Checks for wildcard dependencies in the `Cargo.toml`.
+
+### Why is this bad?
+[As the edition guide says](https://rust-lang-nursery.github.io/edition-guide/rust-2018/cargo-and-crates-io/crates-io-disallows-wildcard-dependencies.html),
+it is highly unlikely that you work with any possible version of your dependency,
+and wildcard dependencies would cause unnecessary breakage in the ecosystem.
+
+### Example
+```
+[dependencies]
+regex = "*"
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/wildcard_enum_match_arm.txt b/src/tools/clippy/src/docs/wildcard_enum_match_arm.txt
new file mode 100644
index 000000000000..09807c01c652
--- /dev/null
+++ b/src/tools/clippy/src/docs/wildcard_enum_match_arm.txt
@@ -0,0 +1,25 @@
+### What it does
+Checks for wildcard enum matches using `_`.
+
+### Why is this bad?
+New enum variants added by library updates can be missed.
+
+### Known problems
+Suggested replacements may be incorrect if guards exhaustively cover some
+variants, and also may not use correct path to enum if it's not present in the current scope.
+
+### Example
+```
+match x {
+    Foo::A(_) => {},
+    _ => {},
+}
+```
+
+Use instead:
+```
+match x {
+    Foo::A(_) => {},
+    Foo::B(_) => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/wildcard_imports.txt b/src/tools/clippy/src/docs/wildcard_imports.txt
new file mode 100644
index 000000000000..bd56aa5b0828
--- /dev/null
+++ b/src/tools/clippy/src/docs/wildcard_imports.txt
@@ -0,0 +1,45 @@
+### What it does
+Checks for wildcard imports `use _::*`.
+
+### Why is this bad?
+wildcard imports can pollute the namespace. This is especially bad if
+you try to import something through a wildcard, that already has been imported by name from
+a different source:
+
+```
+use crate1::foo; // Imports a function named foo
+use crate2::*; // Has a function named foo
+
+foo(); // Calls crate1::foo
+```
+
+This can lead to confusing error messages at best and to unexpected behavior at worst.
+
+### Exceptions
+Wildcard imports are allowed from modules named `prelude`. Many crates (including the standard library)
+provide modules named "prelude" specifically designed for wildcard import.
+
+`use super::*` is allowed in test modules. This is defined as any module with "test" in the name.
+
+These exceptions can be disabled using the `warn-on-all-wildcard-imports` configuration flag.
+
+### Known problems
+If macros are imported through the wildcard, this macro is not included
+by the suggestion and has to be added by hand.
+
+Applying the suggestion when explicit imports of the things imported with a glob import
+exist, may result in `unused_imports` warnings.
+
+### Example
+```
+use crate1::*;
+
+foo();
+```
+
+Use instead:
+```
+use crate1::foo;
+
+foo();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/wildcard_in_or_patterns.txt b/src/tools/clippy/src/docs/wildcard_in_or_patterns.txt
new file mode 100644
index 000000000000..70468ca41e0b
--- /dev/null
+++ b/src/tools/clippy/src/docs/wildcard_in_or_patterns.txt
@@ -0,0 +1,22 @@
+### What it does
+Checks for wildcard pattern used with others patterns in same match arm.
+
+### Why is this bad?
+Wildcard pattern already covers any other pattern as it will match anyway.
+It makes the code less readable, especially to spot wildcard pattern use in match arm.
+
+### Example
+```
+match s {
+    "a" => {},
+    "bar" | _ => {},
+}
+```
+
+Use instead:
+```
+match s {
+    "a" => {},
+    _ => {},
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/write_literal.txt b/src/tools/clippy/src/docs/write_literal.txt
new file mode 100644
index 000000000000..a7a884d08711
--- /dev/null
+++ b/src/tools/clippy/src/docs/write_literal.txt
@@ -0,0 +1,17 @@
+### What it does
+This lint warns about the use of literals as `write!`/`writeln!` args.
+
+### Why is this bad?
+Using literals as `writeln!` args is inefficient
+(c.f., https://github.com/matthiaskrgr/rust-str-bench) and unnecessary
+(i.e., just put the literal in the format string)
+
+### Example
+```
+writeln!(buf, "{}", "foo");
+```
+
+Use instead:
+```
+writeln!(buf, "foo");
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/write_with_newline.txt b/src/tools/clippy/src/docs/write_with_newline.txt
new file mode 100644
index 000000000000..22845fd6515b
--- /dev/null
+++ b/src/tools/clippy/src/docs/write_with_newline.txt
@@ -0,0 +1,18 @@
+### What it does
+This lint warns when you use `write!()` with a format
+string that
+ends in a newline.
+
+### Why is this bad?
+You should use `writeln!()` instead, which appends the
+newline.
+
+### Example
+```
+write!(buf, "Hello {}!\n", name);
+```
+
+Use instead:
+```
+writeln!(buf, "Hello {}!", name);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/writeln_empty_string.txt b/src/tools/clippy/src/docs/writeln_empty_string.txt
new file mode 100644
index 000000000000..3b3aeb79a48b
--- /dev/null
+++ b/src/tools/clippy/src/docs/writeln_empty_string.txt
@@ -0,0 +1,16 @@
+### What it does
+This lint warns when you use `writeln!(buf, "")` to
+print a newline.
+
+### Why is this bad?
+You should use `writeln!(buf)`, which is simpler.
+
+### Example
+```
+writeln!(buf, "");
+```
+
+Use instead:
+```
+writeln!(buf);
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/wrong_self_convention.txt b/src/tools/clippy/src/docs/wrong_self_convention.txt
new file mode 100644
index 000000000000..d6b69ab87f86
--- /dev/null
+++ b/src/tools/clippy/src/docs/wrong_self_convention.txt
@@ -0,0 +1,39 @@
+### What it does
+Checks for methods with certain name prefixes and which
+doesn't match how self is taken. The actual rules are:
+
+|Prefix |Postfix     |`self` taken                   | `self` type  |
+|-------|------------|-------------------------------|--------------|
+|`as_`  | none       |`&self` or `&mut self`         | any          |
+|`from_`| none       | none                          | any          |
+|`into_`| none       |`self`                         | any          |
+|`is_`  | none       |`&mut self` or `&self` or none | any          |
+|`to_`  | `_mut`     |`&mut self`                    | any          |
+|`to_`  | not `_mut` |`self`                         | `Copy`       |
+|`to_`  | not `_mut` |`&self`                        | not `Copy`   |
+
+Note: Clippy doesn't trigger methods with `to_` prefix in:
+- Traits definition.
+Clippy can not tell if a type that implements a trait is `Copy` or not.
+- Traits implementation, when `&self` is taken.
+The method signature is controlled by the trait and often `&self` is required for all types that implement the trait
+(see e.g. the `std::string::ToString` trait).
+
+Clippy allows `Pin<&Self>` and `Pin<&mut Self>` if `&self` and `&mut self` is required.
+
+Please find more info here:
+https://rust-lang.github.io/api-guidelines/naming.html#ad-hoc-conversions-follow-as_-to_-into_-conventions-c-conv
+
+### Why is this bad?
+Consistency breeds readability. If you follow the
+conventions, your users won't be surprised that they, e.g., need to supply a
+mutable reference to a `as_..` function.
+
+### Example
+```
+impl X {
+    fn as_str(self) -> &'static str {
+        // ..
+    }
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/wrong_transmute.txt b/src/tools/clippy/src/docs/wrong_transmute.txt
new file mode 100644
index 000000000000..9fc71e0e382e
--- /dev/null
+++ b/src/tools/clippy/src/docs/wrong_transmute.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for transmutes that can't ever be correct on any
+architecture.
+
+### Why is this bad?
+It's basically guaranteed to be undefined behavior.
+
+### Known problems
+When accessing C, users might want to store pointer
+sized objects in `extradata` arguments to save an allocation.
+
+### Example
+```
+let ptr: *const T = core::intrinsics::transmute('x')
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/zero_divided_by_zero.txt b/src/tools/clippy/src/docs/zero_divided_by_zero.txt
new file mode 100644
index 000000000000..394de20c0c0c
--- /dev/null
+++ b/src/tools/clippy/src/docs/zero_divided_by_zero.txt
@@ -0,0 +1,15 @@
+### What it does
+Checks for `0.0 / 0.0`.
+
+### Why is this bad?
+It's less readable than `f32::NAN` or `f64::NAN`.
+
+### Example
+```
+let nan = 0.0f32 / 0.0;
+```
+
+Use instead:
+```
+let nan = f32::NAN;
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/zero_prefixed_literal.txt b/src/tools/clippy/src/docs/zero_prefixed_literal.txt
new file mode 100644
index 000000000000..5c5588725363
--- /dev/null
+++ b/src/tools/clippy/src/docs/zero_prefixed_literal.txt
@@ -0,0 +1,32 @@
+### What it does
+Warns if an integral constant literal starts with `0`.
+
+### Why is this bad?
+In some languages (including the infamous C language
+and most of its
+family), this marks an octal constant. In Rust however, this is a decimal
+constant. This could
+be confusing for both the writer and a reader of the constant.
+
+### Example
+
+In Rust:
+```
+fn main() {
+    let a = 0123;
+    println!("{}", a);
+}
+```
+
+prints `123`, while in C:
+
+```
+#include <stdio.h>
+
+int main() {
+    int a = 0123;
+    printf("%d\n", a);
+}
+```
+
+prints `83` (as `83 == 0o123` while `123 == 0o173`).
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/zero_ptr.txt b/src/tools/clippy/src/docs/zero_ptr.txt
new file mode 100644
index 000000000000..e768a0236600
--- /dev/null
+++ b/src/tools/clippy/src/docs/zero_ptr.txt
@@ -0,0 +1,16 @@
+### What it does
+Catch casts from `0` to some pointer type
+
+### Why is this bad?
+This generally means `null` and is better expressed as
+{`std`, `core`}`::ptr::`{`null`, `null_mut`}.
+
+### Example
+```
+let a = 0 as *const u32;
+```
+
+Use instead:
+```
+let a = std::ptr::null::<u32>();
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/zero_sized_map_values.txt b/src/tools/clippy/src/docs/zero_sized_map_values.txt
new file mode 100644
index 000000000000..0502bdbf3950
--- /dev/null
+++ b/src/tools/clippy/src/docs/zero_sized_map_values.txt
@@ -0,0 +1,24 @@
+### What it does
+Checks for maps with zero-sized value types anywhere in the code.
+
+### Why is this bad?
+Since there is only a single value for a zero-sized type, a map
+containing zero sized values is effectively a set. Using a set in that case improves
+readability and communicates intent more clearly.
+
+### Known problems
+* A zero-sized type cannot be recovered later if it contains private fields.
+* This lints the signature of public items
+
+### Example
+```
+fn unique_words(text: &str) -> HashMap<&str, ()> {
+    todo!();
+}
+```
+Use instead:
+```
+fn unique_words(text: &str) -> HashSet<&str> {
+    todo!();
+}
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/docs/zst_offset.txt b/src/tools/clippy/src/docs/zst_offset.txt
new file mode 100644
index 000000000000..5810455ee955
--- /dev/null
+++ b/src/tools/clippy/src/docs/zst_offset.txt
@@ -0,0 +1,11 @@
+### What it does
+Checks for `offset(_)`, `wrapping_`{`add`, `sub`}, etc. on raw pointers to
+zero-sized types
+
+### Why is this bad?
+This is a no-op, and likely unintended
+
+### Example
+```
+unsafe { (&() as *const ()).offset(1) };
+```
\ No newline at end of file
diff --git a/src/tools/clippy/src/main.rs b/src/tools/clippy/src/main.rs
index 9ee4a40cbf24..4a32e0e54a81 100644
--- a/src/tools/clippy/src/main.rs
+++ b/src/tools/clippy/src/main.rs
@@ -7,6 +7,8 @@ use std::env;
 use std::path::PathBuf;
 use std::process::{self, Command};
 
+mod docs;
+
 const CARGO_CLIPPY_HELP: &str = r#"Checks a package to catch common mistakes and improve your Rust code.
 
 Usage:
@@ -17,6 +19,7 @@ Common options:
     --fix                    Automatically apply lint suggestions. This flag implies `--no-deps`
     -h, --help               Print this message
     -V, --version            Print version info and exit
+    --explain LINT           Print the documentation for a given lint
 
 Other options are the same as `cargo check`.
 
@@ -54,6 +57,16 @@ pub fn main() {
         return;
     }
 
+    if let Some(pos) = env::args().position(|a| a == "--explain") {
+        if let Some(mut lint) = env::args().nth(pos + 1) {
+            lint.make_ascii_lowercase();
+            docs::explain(&lint.strip_prefix("clippy::").unwrap_or(&lint).replace('-', "_"));
+        } else {
+            show_help();
+        }
+        return;
+    }
+
     if let Err(code) = process(env::args().skip(2)) {
         process::exit(code);
     }
diff --git a/src/tools/clippy/tests/check-fmt.rs b/src/tools/clippy/tests/check-fmt.rs
index 0defd45b68b0..e106583de4a2 100644
--- a/src/tools/clippy/tests/check-fmt.rs
+++ b/src/tools/clippy/tests/check-fmt.rs
@@ -13,7 +13,7 @@ fn fmt() {
     let root_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
     let output = Command::new("cargo")
         .current_dir(root_dir)
-        .args(&["dev", "fmt", "--check"])
+        .args(["dev", "fmt", "--check"])
         .output()
         .unwrap();
 
diff --git a/src/tools/clippy/tests/compile-test.rs b/src/tools/clippy/tests/compile-test.rs
index 92ac1a2be561..ba6186e599e9 100644
--- a/src/tools/clippy/tests/compile-test.rs
+++ b/src/tools/clippy/tests/compile-test.rs
@@ -393,8 +393,8 @@ const RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS: &[&str] = &[
     "search_is_some.rs",
     "single_component_path_imports_nested_first.rs",
     "string_add.rs",
+    "suspicious_to_owned.rs",
     "toplevel_ref_arg_non_rustfix.rs",
-    "trait_duplication_in_bounds.rs",
     "unit_arg.rs",
     "unnecessary_clone.rs",
     "unnecessary_lazy_eval_unfixable.rs",
@@ -404,16 +404,23 @@ const RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS: &[&str] = &[
 ];
 
 fn check_rustfix_coverage() {
-    let missing_coverage_path = Path::new("target/debug/test/ui/rustfix_missing_coverage.txt");
+    let missing_coverage_path = Path::new("debug/test/ui/rustfix_missing_coverage.txt");
+    let missing_coverage_path = if let Ok(target_dir) = std::env::var("CARGO_TARGET_DIR") {
+        PathBuf::from(target_dir).join(missing_coverage_path)
+    } else {
+        missing_coverage_path.to_path_buf()
+    };
 
     if let Ok(missing_coverage_contents) = std::fs::read_to_string(missing_coverage_path) {
         assert!(RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS.iter().is_sorted_by_key(Path::new));
 
-        for rs_path in missing_coverage_contents.lines() {
-            if Path::new(rs_path).starts_with("tests/ui/crashes") {
+        for rs_file in missing_coverage_contents.lines() {
+            let rs_path = Path::new(rs_file);
+            if rs_path.starts_with("tests/ui/crashes") {
                 continue;
             }
-            let filename = Path::new(rs_path).strip_prefix("tests/ui/").unwrap();
+            assert!(rs_path.starts_with("tests/ui/"), "{:?}", rs_file);
+            let filename = rs_path.strip_prefix("tests/ui/").unwrap();
             assert!(
                 RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS
                     .binary_search_by_key(&filename, Path::new)
@@ -421,7 +428,7 @@ fn check_rustfix_coverage() {
                 "`{}` runs `MachineApplicable` diagnostics but is missing a `run-rustfix` annotation. \
                 Please either add `// run-rustfix` at the top of the file or add the file to \
                 `RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS` in `tests/compile-test.rs`.",
-                rs_path,
+                rs_file,
             );
         }
     }
diff --git a/src/tools/clippy/tests/dogfood.rs b/src/tools/clippy/tests/dogfood.rs
index 5697e8680cd6..961525bbd910 100644
--- a/src/tools/clippy/tests/dogfood.rs
+++ b/src/tools/clippy/tests/dogfood.rs
@@ -87,11 +87,11 @@ fn run_clippy_for_package(project: &str, args: &[&str]) {
 
     if cfg!(feature = "internal") {
         // internal lints only exist if we build with the internal feature
-        command.args(&["-D", "clippy::internal"]);
+        command.args(["-D", "clippy::internal"]);
     } else {
         // running a clippy built without internal lints on the clippy source
         // that contains e.g. `allow(clippy::invalid_paths)`
-        command.args(&["-A", "unknown_lints"]);
+        command.args(["-A", "unknown_lints"]);
     }
 
     let output = command.output().unwrap();
diff --git a/src/tools/clippy/tests/integration.rs b/src/tools/clippy/tests/integration.rs
index c64425fa01a4..23a9bef3ccce 100644
--- a/src/tools/clippy/tests/integration.rs
+++ b/src/tools/clippy/tests/integration.rs
@@ -19,7 +19,7 @@ fn integration_test() {
     repo_dir.push(crate_name);
 
     let st = Command::new("git")
-        .args(&[
+        .args([
             OsStr::new("clone"),
             OsStr::new("--depth=1"),
             OsStr::new(&repo_url),
@@ -37,7 +37,7 @@ fn integration_test() {
         .current_dir(repo_dir)
         .env("RUST_BACKTRACE", "full")
         .env("CARGO_TARGET_DIR", target_dir)
-        .args(&[
+        .args([
             "clippy",
             "--all-targets",
             "--all-features",
diff --git a/src/tools/clippy/tests/lint_message_convention.rs b/src/tools/clippy/tests/lint_message_convention.rs
index c3aae1a9aa2d..2e0f4e76075b 100644
--- a/src/tools/clippy/tests/lint_message_convention.rs
+++ b/src/tools/clippy/tests/lint_message_convention.rs
@@ -19,7 +19,7 @@ impl Message {
         // we don't want the first letter after "error: ", "help: " ... to be capitalized
         // also no punctuation (except for "?" ?) at the end of a line
         static REGEX_SET: LazyLock<RegexSet> = LazyLock::new(|| {
-            RegexSet::new(&[
+            RegexSet::new([
                 r"error: [A-Z]",
                 r"help: [A-Z]",
                 r"warning: [A-Z]",
@@ -37,7 +37,7 @@ impl Message {
         // sometimes the first character is capitalized and it is legal (like in "C-like enum variants") or
         // we want to ask a question ending in "?"
         static EXCEPTIONS_SET: LazyLock<RegexSet> = LazyLock::new(|| {
-            RegexSet::new(&[
+            RegexSet::new([
                 r"\.\.\.$",
                 r".*C-like enum variant discriminant is not portable to 32-bit targets",
                 r".*Intel x86 assembly syntax used",
diff --git a/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/Cargo.toml b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/Cargo.toml
new file mode 100644
index 000000000000..a822fad388f5
--- /dev/null
+++ b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "fail-mod-remap"
+version = "0.1.0"
+edition = "2018"
+publish = false
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/bad.rs b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/bad.rs
new file mode 100644
index 000000000000..509aad18622b
--- /dev/null
+++ b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/bad.rs
@@ -0,0 +1 @@
+pub mod inner;
diff --git a/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/bad/inner.rs b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/bad/inner.rs
new file mode 100644
index 000000000000..8b137891791f
--- /dev/null
+++ b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/bad/inner.rs
@@ -0,0 +1 @@
+
diff --git a/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/main.rs b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/main.rs
new file mode 100644
index 000000000000..ba4c8c873dd5
--- /dev/null
+++ b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/main.rs
@@ -0,0 +1,7 @@
+// compile-flags: --remap-path-prefix {{src-base}}=/remapped
+
+#![warn(clippy::self_named_module_files)]
+
+mod bad;
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/main.stderr b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/main.stderr
new file mode 100644
index 000000000000..46991ff662e5
--- /dev/null
+++ b/src/tools/clippy/tests/ui-cargo/module_style/fail_mod_remap/src/main.stderr
@@ -0,0 +1,11 @@
+error: `mod.rs` files are required, found `bad.rs`
+  --> /remapped/module_style/fail_mod_remap/src/bad.rs:1:1
+   |
+LL | pub mod inner;
+   | ^
+   |
+   = note: `-D clippy::self-named-module-files` implied by `-D warnings`
+   = help: move `bad.rs` to `bad/mod.rs`
+
+error: aborting due to previous error
+
diff --git a/src/tools/clippy/tests/ui-toml/arithmetic_allowed/clippy.toml b/src/tools/clippy/tests/ui-toml/arithmetic_allowed/clippy.toml
deleted file mode 100644
index cc40570b12a0..000000000000
--- a/src/tools/clippy/tests/ui-toml/arithmetic_allowed/clippy.toml
+++ /dev/null
@@ -1 +0,0 @@
-arithmetic-allowed = ["Point"]
diff --git a/src/tools/clippy/tests/ui-toml/arithmetic_allowed/arithmetic_allowed.rs b/src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/arithmetic_side_effects_allowed.rs
similarity index 89%
rename from src/tools/clippy/tests/ui-toml/arithmetic_allowed/arithmetic_allowed.rs
rename to src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/arithmetic_side_effects_allowed.rs
index 195fabdbf710..1aed09b7c7bd 100644
--- a/src/tools/clippy/tests/ui-toml/arithmetic_allowed/arithmetic_allowed.rs
+++ b/src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/arithmetic_side_effects_allowed.rs
@@ -1,4 +1,4 @@
-#![warn(clippy::arithmetic)]
+#![warn(clippy::arithmetic_side_effects)]
 
 use core::ops::Add;
 
diff --git a/src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/clippy.toml b/src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/clippy.toml
new file mode 100644
index 000000000000..e736256f29a4
--- /dev/null
+++ b/src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/clippy.toml
@@ -0,0 +1 @@
+arithmetic-side-effects-allowed = ["Point"]
diff --git a/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.rs b/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.rs
index 5b4adc868dff..ed8161acc0ef 100644
--- a/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.rs
+++ b/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.rs
@@ -42,6 +42,7 @@ macro_rules! printlnfoo {
 fn main() {
     let _ = vec! {1, 2, 3};
     let _ = format!["ugh {} stop being such a good compiler", "hello"];
+    let _ = matches!{{}, ()};
     let _ = quote!(let x = 1;);
     let _ = quote::quote!(match match match);
     let _ = test!(); // trigger when macro def is inside our own crate
diff --git a/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.stderr b/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.stderr
index 039b23b1bdb2..d80ad49f3086 100644
--- a/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.stderr
+++ b/src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.stderr
@@ -23,26 +23,38 @@ help: consider writing `format!("ugh () stop being such a good compiler", "hello
 LL |     let _ = format!["ugh {} stop being such a good compiler", "hello"];
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: use of irregular braces for `quote!` macro
+error: use of irregular braces for `matches!` macro
   --> $DIR/conf_nonstandard_macro_braces.rs:45:13
    |
+LL |     let _ = matches!{{}, ()};
+   |             ^^^^^^^^^^^^^^^^
+   |
+help: consider writing `matches!((), ())`
+  --> $DIR/conf_nonstandard_macro_braces.rs:45:13
+   |
+LL |     let _ = matches!{{}, ()};
+   |             ^^^^^^^^^^^^^^^^
+
+error: use of irregular braces for `quote!` macro
+  --> $DIR/conf_nonstandard_macro_braces.rs:46:13
+   |
 LL |     let _ = quote!(let x = 1;);
    |             ^^^^^^^^^^^^^^^^^^
    |
 help: consider writing `quote! {let x = 1;}`
-  --> $DIR/conf_nonstandard_macro_braces.rs:45:13
+  --> $DIR/conf_nonstandard_macro_braces.rs:46:13
    |
 LL |     let _ = quote!(let x = 1;);
    |             ^^^^^^^^^^^^^^^^^^
 
 error: use of irregular braces for `quote::quote!` macro
-  --> $DIR/conf_nonstandard_macro_braces.rs:46:13
+  --> $DIR/conf_nonstandard_macro_braces.rs:47:13
    |
 LL |     let _ = quote::quote!(match match match);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 help: consider writing `quote::quote! {match match match}`
-  --> $DIR/conf_nonstandard_macro_braces.rs:46:13
+  --> $DIR/conf_nonstandard_macro_braces.rs:47:13
    |
 LL |     let _ = quote::quote!(match match match);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -67,28 +79,28 @@ LL |     let _ = test!(); // trigger when macro def is inside our own crate
    = note: this error originates in the macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: use of irregular braces for `type_pos!` macro
-  --> $DIR/conf_nonstandard_macro_braces.rs:55:12
+  --> $DIR/conf_nonstandard_macro_braces.rs:56:12
    |
 LL |     let _: type_pos!(usize) = vec![];
    |            ^^^^^^^^^^^^^^^^
    |
 help: consider writing `type_pos![usize]`
-  --> $DIR/conf_nonstandard_macro_braces.rs:55:12
+  --> $DIR/conf_nonstandard_macro_braces.rs:56:12
    |
 LL |     let _: type_pos!(usize) = vec![];
    |            ^^^^^^^^^^^^^^^^
 
 error: use of irregular braces for `eprint!` macro
-  --> $DIR/conf_nonstandard_macro_braces.rs:57:5
+  --> $DIR/conf_nonstandard_macro_braces.rs:58:5
    |
 LL |     eprint!("test if user config overrides defaults");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 help: consider writing `eprint!["test if user config overrides defaults"]`
-  --> $DIR/conf_nonstandard_macro_braces.rs:57:5
+  --> $DIR/conf_nonstandard_macro_braces.rs:58:5
    |
 LL |     eprint!("test if user config overrides defaults");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 7 previous errors
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr b/src/tools/clippy/tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr
index 9f8e778b3b9d..f27f78d15d3a 100644
--- a/src/tools/clippy/tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr
+++ b/src/tools/clippy/tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr
@@ -3,7 +3,7 @@ error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown fie
            allow-expect-in-tests
            allow-unwrap-in-tests
            allowed-scripts
-           arithmetic-allowed
+           arithmetic-side-effects-allowed
            array-size-threshold
            avoid-breaking-exported-api
            await-holding-invalid-types
@@ -19,6 +19,7 @@ error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown fie
            enforced-import-renames
            enum-variant-name-threshold
            enum-variant-size-threshold
+           large-error-threshold
            literal-representation-threshold
            max-fn-params-bools
            max-include-file-size
diff --git a/src/tools/clippy/tests/ui/almost_complete_letter_range.fixed b/src/tools/clippy/tests/ui/almost_complete_letter_range.fixed
index e69b40f35f4c..079b7c000dce 100644
--- a/src/tools/clippy/tests/ui/almost_complete_letter_range.fixed
+++ b/src/tools/clippy/tests/ui/almost_complete_letter_range.fixed
@@ -1,5 +1,6 @@
 // run-rustfix
 // edition:2018
+// aux-build:macro_rules.rs
 
 #![feature(custom_inner_attributes)]
 #![feature(exclusive_range_pattern)]
@@ -8,12 +9,21 @@
 #![allow(ellipsis_inclusive_range_patterns)]
 #![allow(clippy::needless_parens_on_range_literals)]
 
+#[macro_use]
+extern crate macro_rules;
+
 macro_rules! a {
     () => {
         'a'
     };
 }
 
+macro_rules! b {
+    () => {
+        let _ = 'a'..='z';
+    };
+}
+
 fn main() {
     #[rustfmt::skip]
     {
@@ -47,6 +57,9 @@ fn main() {
         'B'..'Z' => 4,
         _ => 5,
     };
+
+    almost_complete_letter_range!();
+    b!();
 }
 
 fn _under_msrv() {
diff --git a/src/tools/clippy/tests/ui/almost_complete_letter_range.rs b/src/tools/clippy/tests/ui/almost_complete_letter_range.rs
index f2240981d45f..a66900a976ef 100644
--- a/src/tools/clippy/tests/ui/almost_complete_letter_range.rs
+++ b/src/tools/clippy/tests/ui/almost_complete_letter_range.rs
@@ -1,5 +1,6 @@
 // run-rustfix
 // edition:2018
+// aux-build:macro_rules.rs
 
 #![feature(custom_inner_attributes)]
 #![feature(exclusive_range_pattern)]
@@ -8,12 +9,21 @@
 #![allow(ellipsis_inclusive_range_patterns)]
 #![allow(clippy::needless_parens_on_range_literals)]
 
+#[macro_use]
+extern crate macro_rules;
+
 macro_rules! a {
     () => {
         'a'
     };
 }
 
+macro_rules! b {
+    () => {
+        let _ = 'a'..'z';
+    };
+}
+
 fn main() {
     #[rustfmt::skip]
     {
@@ -47,6 +57,9 @@ fn main() {
         'B'..'Z' => 4,
         _ => 5,
     };
+
+    almost_complete_letter_range!();
+    b!();
 }
 
 fn _under_msrv() {
diff --git a/src/tools/clippy/tests/ui/almost_complete_letter_range.stderr b/src/tools/clippy/tests/ui/almost_complete_letter_range.stderr
index 5b5dc40ee54d..3de44c72c1b9 100644
--- a/src/tools/clippy/tests/ui/almost_complete_letter_range.stderr
+++ b/src/tools/clippy/tests/ui/almost_complete_letter_range.stderr
@@ -1,5 +1,5 @@
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:20:17
+  --> $DIR/almost_complete_letter_range.rs:30:17
    |
 LL |         let _ = ('a') ..'z';
    |                 ^^^^^^--^^^
@@ -9,7 +9,7 @@ LL |         let _ = ('a') ..'z';
    = note: `-D clippy::almost-complete-letter-range` implied by `-D warnings`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:21:17
+  --> $DIR/almost_complete_letter_range.rs:31:17
    |
 LL |         let _ = 'A' .. ('Z');
    |                 ^^^^--^^^^^^
@@ -17,7 +17,7 @@ LL |         let _ = 'A' .. ('Z');
    |                     help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:27:13
+  --> $DIR/almost_complete_letter_range.rs:37:13
    |
 LL |     let _ = (b'a')..(b'z');
    |             ^^^^^^--^^^^^^
@@ -25,7 +25,7 @@ LL |     let _ = (b'a')..(b'z');
    |                   help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:28:13
+  --> $DIR/almost_complete_letter_range.rs:38:13
    |
 LL |     let _ = b'A'..b'Z';
    |             ^^^^--^^^^
@@ -33,7 +33,7 @@ LL |     let _ = b'A'..b'Z';
    |                 help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:33:13
+  --> $DIR/almost_complete_letter_range.rs:43:13
    |
 LL |     let _ = a!()..'z';
    |             ^^^^--^^^
@@ -41,7 +41,7 @@ LL |     let _ = a!()..'z';
    |                 help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:36:9
+  --> $DIR/almost_complete_letter_range.rs:46:9
    |
 LL |         b'a'..b'z' if true => 1,
    |         ^^^^--^^^^
@@ -49,7 +49,7 @@ LL |         b'a'..b'z' if true => 1,
    |             help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:37:9
+  --> $DIR/almost_complete_letter_range.rs:47:9
    |
 LL |         b'A'..b'Z' if true => 2,
    |         ^^^^--^^^^
@@ -57,7 +57,7 @@ LL |         b'A'..b'Z' if true => 2,
    |             help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:44:9
+  --> $DIR/almost_complete_letter_range.rs:54:9
    |
 LL |         'a'..'z' if true => 1,
    |         ^^^--^^^
@@ -65,7 +65,7 @@ LL |         'a'..'z' if true => 1,
    |            help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:45:9
+  --> $DIR/almost_complete_letter_range.rs:55:9
    |
 LL |         'A'..'Z' if true => 2,
    |         ^^^--^^^
@@ -73,7 +73,20 @@ LL |         'A'..'Z' if true => 2,
    |            help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:55:9
+  --> $DIR/almost_complete_letter_range.rs:23:17
+   |
+LL |         let _ = 'a'..'z';
+   |                 ^^^--^^^
+   |                    |
+   |                    help: use an inclusive range: `..=`
+...
+LL |     b!();
+   |     ---- in this macro invocation
+   |
+   = note: this error originates in the macro `b` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: almost complete ascii letter range
+  --> $DIR/almost_complete_letter_range.rs:68:9
    |
 LL |         'a'..'z' => 1,
    |         ^^^--^^^
@@ -81,7 +94,7 @@ LL |         'a'..'z' => 1,
    |            help: use an inclusive range: `...`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:62:13
+  --> $DIR/almost_complete_letter_range.rs:75:13
    |
 LL |     let _ = 'a'..'z';
    |             ^^^--^^^
@@ -89,12 +102,12 @@ LL |     let _ = 'a'..'z';
    |                help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:64:9
+  --> $DIR/almost_complete_letter_range.rs:77:9
    |
 LL |         'a'..'z' => 1,
    |         ^^^--^^^
    |            |
    |            help: use an inclusive range: `..=`
 
-error: aborting due to 12 previous errors
+error: aborting due to 13 previous errors
 
diff --git a/src/tools/clippy/tests/ui/arithmetic.fixed b/src/tools/clippy/tests/ui/arithmetic.fixed
deleted file mode 100644
index a2a1c4394c21..000000000000
--- a/src/tools/clippy/tests/ui/arithmetic.fixed
+++ /dev/null
@@ -1,27 +0,0 @@
-// run-rustfix
-
-#![allow(clippy::unnecessary_owned_empty_strings)]
-#![feature(saturating_int_impl)]
-#![warn(clippy::arithmetic)]
-
-use core::num::{Saturating, Wrapping};
-
-pub fn hard_coded_allowed() {
-    let _ = Saturating(0u32) + Saturating(0u32);
-    let _ = String::new() + "";
-    let _ = Wrapping(0u32) + Wrapping(0u32);
-
-    let saturating: Saturating<u32> = Saturating(0u32);
-    let string: String = String::new();
-    let wrapping: Wrapping<u32> = Wrapping(0u32);
-
-    let inferred_saturating = saturating + saturating;
-    let inferred_string = string + "";
-    let inferred_wrapping = wrapping + wrapping;
-
-    let _ = inferred_saturating + inferred_saturating;
-    let _ = inferred_string + "";
-    let _ = inferred_wrapping + inferred_wrapping;
-}
-
-fn main() {}
diff --git a/src/tools/clippy/tests/ui/arithmetic.rs b/src/tools/clippy/tests/ui/arithmetic.rs
deleted file mode 100644
index a2a1c4394c21..000000000000
--- a/src/tools/clippy/tests/ui/arithmetic.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// run-rustfix
-
-#![allow(clippy::unnecessary_owned_empty_strings)]
-#![feature(saturating_int_impl)]
-#![warn(clippy::arithmetic)]
-
-use core::num::{Saturating, Wrapping};
-
-pub fn hard_coded_allowed() {
-    let _ = Saturating(0u32) + Saturating(0u32);
-    let _ = String::new() + "";
-    let _ = Wrapping(0u32) + Wrapping(0u32);
-
-    let saturating: Saturating<u32> = Saturating(0u32);
-    let string: String = String::new();
-    let wrapping: Wrapping<u32> = Wrapping(0u32);
-
-    let inferred_saturating = saturating + saturating;
-    let inferred_string = string + "";
-    let inferred_wrapping = wrapping + wrapping;
-
-    let _ = inferred_saturating + inferred_saturating;
-    let _ = inferred_string + "";
-    let _ = inferred_wrapping + inferred_wrapping;
-}
-
-fn main() {}
diff --git a/src/tools/clippy/tests/ui/arithmetic_side_effects.rs b/src/tools/clippy/tests/ui/arithmetic_side_effects.rs
new file mode 100644
index 000000000000..dd24f5aa592b
--- /dev/null
+++ b/src/tools/clippy/tests/ui/arithmetic_side_effects.rs
@@ -0,0 +1,139 @@
+#![allow(
+    clippy::assign_op_pattern,
+    clippy::erasing_op,
+    clippy::identity_op,
+    clippy::unnecessary_owned_empty_strings,
+    arithmetic_overflow,
+    unconditional_panic
+)]
+#![feature(inline_const, saturating_int_impl)]
+#![warn(clippy::arithmetic_side_effects)]
+
+use core::num::{Saturating, Wrapping};
+
+pub fn association_with_structures_should_not_trigger_the_lint() {
+    enum Foo {
+        Bar = -2,
+    }
+
+    impl Trait for Foo {
+        const ASSOC: i32 = {
+            let _: [i32; 1 + 1];
+            fn foo() {}
+            1 + 1
+        };
+    }
+
+    struct Baz([i32; 1 + 1]);
+
+    trait Trait {
+        const ASSOC: i32 = 1 + 1;
+    }
+
+    type Alias = [i32; 1 + 1];
+
+    union Qux {
+        field: [i32; 1 + 1],
+    }
+
+    let _: [i32; 1 + 1] = [0, 0];
+
+    let _: [i32; 1 + 1] = {
+        let a: [i32; 1 + 1] = [0, 0];
+        a
+    };
+}
+
+pub fn hard_coded_allowed() {
+    let _ = 1f32 + 1f32;
+    let _ = 1f64 + 1f64;
+
+    let _ = Saturating(0u32) + Saturating(0u32);
+    let _ = String::new() + "";
+    let _ = Wrapping(0u32) + Wrapping(0u32);
+
+    let saturating: Saturating<u32> = Saturating(0u32);
+    let string: String = String::new();
+    let wrapping: Wrapping<u32> = Wrapping(0u32);
+
+    let inferred_saturating = saturating + saturating;
+    let inferred_string = string + "";
+    let inferred_wrapping = wrapping + wrapping;
+
+    let _ = inferred_saturating + inferred_saturating;
+    let _ = inferred_string + "";
+    let _ = inferred_wrapping + inferred_wrapping;
+}
+
+#[rustfmt::skip]
+pub fn const_ops_should_not_trigger_the_lint() {
+    const _: i32 = { let mut n = 1; n += 1; n };
+    let _ = const { let mut n = 1; n += 1; n };
+
+    const _: i32 = { let mut n = 1; n = n + 1; n };
+    let _ = const { let mut n = 1; n = n + 1; n };
+
+    const _: i32 = { let mut n = 1; n = 1 + n; n };
+    let _ = const { let mut n = 1; n = 1 + n; n };
+
+    const _: i32 = 1 + 1;
+    let _ = const { 1 + 1 };
+
+    const _: i32 = { let mut n = -1; n = -(-1); n = -n; n };
+    let _ = const { let mut n = -1; n = -(-1); n = -n; n };
+}
+
+pub fn non_overflowing_runtime_ops_or_ops_already_handled_by_the_compiler() {
+    let mut _n = i32::MAX;
+
+    // Assign
+    _n += 0;
+    _n -= 0;
+    _n /= 99;
+    _n %= 99;
+    _n *= 0;
+    _n *= 1;
+
+    // Binary
+    _n = _n + 0;
+    _n = 0 + _n;
+    _n = _n - 0;
+    _n = 0 - _n;
+    _n = _n / 99;
+    _n = _n % 99;
+    _n = _n * 0;
+    _n = 0 * _n;
+    _n = _n * 1;
+    _n = 1 * _n;
+    _n = 23 + 85;
+
+    // Unary
+    _n = -1;
+    _n = -(-1);
+}
+
+pub fn overflowing_runtime_ops() {
+    let mut _n = i32::MAX;
+
+    // Assign
+    _n += 1;
+    _n -= 1;
+    _n /= 0;
+    _n %= 0;
+    _n *= 2;
+
+    // Binary
+    _n = _n + 1;
+    _n = 1 + _n;
+    _n = _n - 1;
+    _n = 1 - _n;
+    _n = _n / 0;
+    _n = _n % 0;
+    _n = _n * 2;
+    _n = 2 * _n;
+
+    // Unary
+    _n = -_n;
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/arithmetic_side_effects.stderr b/src/tools/clippy/tests/ui/arithmetic_side_effects.stderr
new file mode 100644
index 000000000000..a2a856efbffc
--- /dev/null
+++ b/src/tools/clippy/tests/ui/arithmetic_side_effects.stderr
@@ -0,0 +1,88 @@
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:119:5
+   |
+LL |     _n += 1;
+   |     ^^^^^^^
+   |
+   = note: `-D clippy::arithmetic-side-effects` implied by `-D warnings`
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:120:5
+   |
+LL |     _n -= 1;
+   |     ^^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:121:5
+   |
+LL |     _n /= 0;
+   |     ^^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:122:5
+   |
+LL |     _n %= 0;
+   |     ^^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:123:5
+   |
+LL |     _n *= 2;
+   |     ^^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:126:10
+   |
+LL |     _n = _n + 1;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:127:10
+   |
+LL |     _n = 1 + _n;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:128:10
+   |
+LL |     _n = _n - 1;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:129:10
+   |
+LL |     _n = 1 - _n;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:130:10
+   |
+LL |     _n = _n / 0;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:131:10
+   |
+LL |     _n = _n % 0;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:132:10
+   |
+LL |     _n = _n * 2;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:133:10
+   |
+LL |     _n = 2 * _n;
+   |          ^^^^^^
+
+error: arithmetic operation that can potentially result in unexpected side-effects
+  --> $DIR/arithmetic_side_effects.rs:136:10
+   |
+LL |     _n = -_n;
+   |          ^^^
+
+error: aborting due to 14 previous errors
+
diff --git a/src/tools/clippy/tests/ui/assertions_on_result_states.fixed b/src/tools/clippy/tests/ui/assertions_on_result_states.fixed
index 795f435f24cd..2bb755290c50 100644
--- a/src/tools/clippy/tests/ui/assertions_on_result_states.fixed
+++ b/src/tools/clippy/tests/ui/assertions_on_result_states.fixed
@@ -75,3 +75,9 @@ fn main() {
     let r: Result<Foo, Foo> = Err(Foo);
     assert!(r.is_err());
 }
+
+#[allow(dead_code)]
+fn issue9450() {
+    let res: Result<i32, i32> = Ok(1);
+    res.unwrap_err();
+}
diff --git a/src/tools/clippy/tests/ui/assertions_on_result_states.rs b/src/tools/clippy/tests/ui/assertions_on_result_states.rs
index 1101aec1e1b3..d8a9bd2f1c45 100644
--- a/src/tools/clippy/tests/ui/assertions_on_result_states.rs
+++ b/src/tools/clippy/tests/ui/assertions_on_result_states.rs
@@ -75,3 +75,9 @@ fn main() {
     let r: Result<Foo, Foo> = Err(Foo);
     assert!(r.is_err());
 }
+
+#[allow(dead_code)]
+fn issue9450() {
+    let res: Result<i32, i32> = Ok(1);
+    assert!(res.is_err())
+}
diff --git a/src/tools/clippy/tests/ui/assertions_on_result_states.stderr b/src/tools/clippy/tests/ui/assertions_on_result_states.stderr
index 97a5f3dfca4a..298d63c9c34f 100644
--- a/src/tools/clippy/tests/ui/assertions_on_result_states.stderr
+++ b/src/tools/clippy/tests/ui/assertions_on_result_states.stderr
@@ -36,5 +36,11 @@ error: called `assert!` with `Result::is_err`
 LL |     assert!(r.is_err());
    |     ^^^^^^^^^^^^^^^^^^^ help: replace with: `r.unwrap_err()`
 
-error: aborting due to 6 previous errors
+error: called `assert!` with `Result::is_err`
+  --> $DIR/assertions_on_result_states.rs:82:5
+   |
+LL |     assert!(res.is_err())
+   |     ^^^^^^^^^^^^^^^^^^^^^ help: replace with: `res.unwrap_err();`
+
+error: aborting due to 7 previous errors
 
diff --git a/src/tools/clippy/tests/ui/author.stdout b/src/tools/clippy/tests/ui/author.stdout
index 3125863036bb..597318a556b8 100644
--- a/src/tools/clippy/tests/ui/author.stdout
+++ b/src/tools/clippy/tests/ui/author.stdout
@@ -6,7 +6,7 @@ if_chain! {
     if match_qpath(qpath, &["char"]);
     if let ExprKind::Lit(ref lit) = expr.kind;
     if let LitKind::Int(69, LitIntType::Unsuffixed) = lit.node;
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name, None) = local.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name, None) = local.pat.kind;
     if name.as_str() == "x";
     then {
         // report your lint here
diff --git a/src/tools/clippy/tests/ui/author/blocks.stdout b/src/tools/clippy/tests/ui/author/blocks.stdout
index 2fc4a7d1f7fe..a529981e2e68 100644
--- a/src/tools/clippy/tests/ui/author/blocks.stdout
+++ b/src/tools/clippy/tests/ui/author/blocks.stdout
@@ -5,13 +5,13 @@ if_chain! {
     if let Some(init) = local.init;
     if let ExprKind::Lit(ref lit) = init.kind;
     if let LitKind::Int(42, LitIntType::Signed(IntTy::I32)) = lit.node;
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name, None) = local.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name, None) = local.pat.kind;
     if name.as_str() == "x";
     if let StmtKind::Local(local1) = block.stmts[1].kind;
     if let Some(init1) = local1.init;
     if let ExprKind::Lit(ref lit1) = init1.kind;
     if let LitKind::Float(_, LitFloatType::Suffixed(FloatTy::F32)) = lit1.node;
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name1, None) = local1.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name1, None) = local1.pat.kind;
     if name1.as_str() == "_t";
     if let StmtKind::Semi(e) = block.stmts[2].kind;
     if let ExprKind::Unary(UnOp::Neg, inner) = e.kind;
@@ -31,7 +31,7 @@ if_chain! {
     if let ExprKind::Path(ref qpath) = func.kind;
     if match_qpath(qpath, &["String", "new"]);
     if args.is_empty();
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name, None) = local.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name, None) = local.pat.kind;
     if name.as_str() == "expr";
     if let Some(trailing_expr) = block.expr;
     if let ExprKind::Call(func1, args1) = trailing_expr.kind;
diff --git a/src/tools/clippy/tests/ui/author/loop.stdout b/src/tools/clippy/tests/ui/author/loop.stdout
index 3d9560f697a7..ceb53fcd4963 100644
--- a/src/tools/clippy/tests/ui/author/loop.stdout
+++ b/src/tools/clippy/tests/ui/author/loop.stdout
@@ -1,6 +1,6 @@
 if_chain! {
     if let Some(higher::ForLoop { pat: pat, arg: arg, body: body, .. }) = higher::ForLoop::hir(expr);
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name, None) = pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name, None) = pat.kind;
     if name.as_str() == "y";
     if let ExprKind::Struct(qpath, fields, None) = arg.kind;
     if matches!(qpath, QPath::LangItem(LangItem::Range, _));
@@ -17,7 +17,7 @@ if_chain! {
     if let Some(init) = local.init;
     if let ExprKind::Path(ref qpath1) = init.kind;
     if match_qpath(qpath1, &["y"]);
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name1, None) = local.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name1, None) = local.pat.kind;
     if name1.as_str() == "z";
     if block.expr.is_none();
     then {
diff --git a/src/tools/clippy/tests/ui/author/matches.stdout b/src/tools/clippy/tests/ui/author/matches.stdout
index 38444a0094ca..2cf69a035b4c 100644
--- a/src/tools/clippy/tests/ui/author/matches.stdout
+++ b/src/tools/clippy/tests/ui/author/matches.stdout
@@ -21,7 +21,7 @@ if_chain! {
     if let Some(init1) = local1.init;
     if let ExprKind::Lit(ref lit4) = init1.kind;
     if let LitKind::Int(3, LitIntType::Unsuffixed) = lit4.node;
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name, None) = local1.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name, None) = local1.pat.kind;
     if name.as_str() == "x";
     if let Some(trailing_expr) = block.expr;
     if let ExprKind::Path(ref qpath) = trailing_expr.kind;
@@ -30,7 +30,7 @@ if_chain! {
     if arms[2].guard.is_none();
     if let ExprKind::Lit(ref lit5) = arms[2].body.kind;
     if let LitKind::Int(1, LitIntType::Unsuffixed) = lit5.node;
-    if let PatKind::Binding(BindingAnnotation::Unannotated, _, name1, None) = local.pat.kind;
+    if let PatKind::Binding(BindingAnnotation::NONE, _, name1, None) = local.pat.kind;
     if name1.as_str() == "a";
     then {
         // report your lint here
diff --git a/src/tools/clippy/tests/ui/author/struct.rs b/src/tools/clippy/tests/ui/author/struct.rs
index 5fdf3433a370..a99bdfc13137 100644
--- a/src/tools/clippy/tests/ui/author/struct.rs
+++ b/src/tools/clippy/tests/ui/author/struct.rs
@@ -1,4 +1,9 @@
-#[allow(clippy::unnecessary_operation, clippy::single_match)]
+#![allow(
+    clippy::unnecessary_operation,
+    clippy::single_match,
+    clippy::no_effect,
+    clippy::bool_to_int_with_if
+)]
 fn main() {
     struct Test {
         field: u32,
diff --git a/src/tools/clippy/tests/ui/author/struct.stdout b/src/tools/clippy/tests/ui/author/struct.stdout
index 5e78b7c9de7e..b5bbc9e213c6 100644
--- a/src/tools/clippy/tests/ui/author/struct.stdout
+++ b/src/tools/clippy/tests/ui/author/struct.stdout
@@ -53,11 +53,11 @@ if_chain! {
     }
 }
 if_chain! {
-    if let ExprKind::MethodCall(method_name, args, _) = expr.kind;
+    if let ExprKind::MethodCall(method_name, receiver, args, _) = expr.kind;
     if method_name.ident.as_str() == "test";
-    if args.len() == 1;
-    if let ExprKind::Path(ref qpath) = args[0].kind;
+    if let ExprKind::Path(ref qpath) = receiver.kind;
     if match_qpath(qpath, &["test_method_call"]);
+    if args.is_empty();
     then {
         // report your lint here
     }
diff --git a/src/tools/clippy/tests/ui/auxiliary/macro_rules.rs b/src/tools/clippy/tests/ui/auxiliary/macro_rules.rs
index 83a0af6b87ac..ef3ca9aea380 100644
--- a/src/tools/clippy/tests/ui/auxiliary/macro_rules.rs
+++ b/src/tools/clippy/tests/ui/auxiliary/macro_rules.rs
@@ -140,3 +140,10 @@ macro_rules! manual_rem_euclid {
 macro_rules! equatable_if_let {
     ($a:ident) => {{ if let 2 = $a {} }};
 }
+
+#[macro_export]
+macro_rules! almost_complete_letter_range {
+    () => {
+        let _ = 'a'..'z';
+    };
+}
diff --git a/src/tools/clippy/tests/ui/bool_to_int_with_if.fixed b/src/tools/clippy/tests/ui/bool_to_int_with_if.fixed
new file mode 100644
index 000000000000..2c8339cdd7f8
--- /dev/null
+++ b/src/tools/clippy/tests/ui/bool_to_int_with_if.fixed
@@ -0,0 +1,91 @@
+// run-rustfix
+
+#![warn(clippy::bool_to_int_with_if)]
+#![allow(unused, dead_code, clippy::unnecessary_operation, clippy::no_effect)]
+
+fn main() {
+    let a = true;
+    let b = false;
+
+    let x = 1;
+    let y = 2;
+
+    // Should lint
+    // precedence
+    i32::from(a);
+    i32::from(!a);
+    i32::from(!a);
+    i32::from(a || b);
+    i32::from(cond(a, b));
+    i32::from(x + y < 4);
+
+    // if else if
+    if a {
+        123
+    } else { i32::from(b) };
+
+    // if else if inverted
+    if a {
+        123
+    } else { i32::from(!b) };
+
+    // Shouldn't lint
+
+    if a {
+        1
+    } else if b {
+        0
+    } else {
+        3
+    };
+
+    if a {
+        3
+    } else if b {
+        1
+    } else {
+        -2
+    };
+
+    if a {
+        3
+    } else {
+        0
+    };
+    if a {
+        side_effect();
+        1
+    } else {
+        0
+    };
+    if a {
+        1
+    } else {
+        side_effect();
+        0
+    };
+
+    // multiple else ifs
+    if a {
+        123
+    } else if b {
+        1
+    } else if a | b {
+        0
+    } else {
+        123
+    };
+
+    some_fn(a);
+}
+
+// Lint returns and type inference
+fn some_fn(a: bool) -> u8 {
+    u8::from(a)
+}
+
+fn side_effect() {}
+
+fn cond(a: bool, b: bool) -> bool {
+    a || b
+}
diff --git a/src/tools/clippy/tests/ui/bool_to_int_with_if.rs b/src/tools/clippy/tests/ui/bool_to_int_with_if.rs
new file mode 100644
index 000000000000..5d9496f01775
--- /dev/null
+++ b/src/tools/clippy/tests/ui/bool_to_int_with_if.rs
@@ -0,0 +1,123 @@
+// run-rustfix
+
+#![warn(clippy::bool_to_int_with_if)]
+#![allow(unused, dead_code, clippy::unnecessary_operation, clippy::no_effect)]
+
+fn main() {
+    let a = true;
+    let b = false;
+
+    let x = 1;
+    let y = 2;
+
+    // Should lint
+    // precedence
+    if a {
+        1
+    } else {
+        0
+    };
+    if a {
+        0
+    } else {
+        1
+    };
+    if !a {
+        1
+    } else {
+        0
+    };
+    if a || b {
+        1
+    } else {
+        0
+    };
+    if cond(a, b) {
+        1
+    } else {
+        0
+    };
+    if x + y < 4 {
+        1
+    } else {
+        0
+    };
+
+    // if else if
+    if a {
+        123
+    } else if b {
+        1
+    } else {
+        0
+    };
+
+    // if else if inverted
+    if a {
+        123
+    } else if b {
+        0
+    } else {
+        1
+    };
+
+    // Shouldn't lint
+
+    if a {
+        1
+    } else if b {
+        0
+    } else {
+        3
+    };
+
+    if a {
+        3
+    } else if b {
+        1
+    } else {
+        -2
+    };
+
+    if a {
+        3
+    } else {
+        0
+    };
+    if a {
+        side_effect();
+        1
+    } else {
+        0
+    };
+    if a {
+        1
+    } else {
+        side_effect();
+        0
+    };
+
+    // multiple else ifs
+    if a {
+        123
+    } else if b {
+        1
+    } else if a | b {
+        0
+    } else {
+        123
+    };
+
+    some_fn(a);
+}
+
+// Lint returns and type inference
+fn some_fn(a: bool) -> u8 {
+    if a { 1 } else { 0 }
+}
+
+fn side_effect() {}
+
+fn cond(a: bool, b: bool) -> bool {
+    a || b
+}
diff --git a/src/tools/clippy/tests/ui/bool_to_int_with_if.stderr b/src/tools/clippy/tests/ui/bool_to_int_with_if.stderr
new file mode 100644
index 000000000000..e695440f6682
--- /dev/null
+++ b/src/tools/clippy/tests/ui/bool_to_int_with_if.stderr
@@ -0,0 +1,109 @@
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:15:5
+   |
+LL | /     if a {
+LL | |         1
+LL | |     } else {
+LL | |         0
+LL | |     };
+   | |_____^ help: replace with from: `i32::from(a)`
+   |
+   = note: `-D clippy::bool-to-int-with-if` implied by `-D warnings`
+   = note: `a as i32` or `a.into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:20:5
+   |
+LL | /     if a {
+LL | |         0
+LL | |     } else {
+LL | |         1
+LL | |     };
+   | |_____^ help: replace with from: `i32::from(!a)`
+   |
+   = note: `!a as i32` or `(!a).into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:25:5
+   |
+LL | /     if !a {
+LL | |         1
+LL | |     } else {
+LL | |         0
+LL | |     };
+   | |_____^ help: replace with from: `i32::from(!a)`
+   |
+   = note: `!a as i32` or `(!a).into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:30:5
+   |
+LL | /     if a || b {
+LL | |         1
+LL | |     } else {
+LL | |         0
+LL | |     };
+   | |_____^ help: replace with from: `i32::from(a || b)`
+   |
+   = note: `(a || b) as i32` or `(a || b).into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:35:5
+   |
+LL | /     if cond(a, b) {
+LL | |         1
+LL | |     } else {
+LL | |         0
+LL | |     };
+   | |_____^ help: replace with from: `i32::from(cond(a, b))`
+   |
+   = note: `cond(a, b) as i32` or `cond(a, b).into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:40:5
+   |
+LL | /     if x + y < 4 {
+LL | |         1
+LL | |     } else {
+LL | |         0
+LL | |     };
+   | |_____^ help: replace with from: `i32::from(x + y < 4)`
+   |
+   = note: `(x + y < 4) as i32` or `(x + y < 4).into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:49:12
+   |
+LL |       } else if b {
+   |  ____________^
+LL | |         1
+LL | |     } else {
+LL | |         0
+LL | |     };
+   | |_____^ help: replace with from: `{ i32::from(b) }`
+   |
+   = note: `b as i32` or `b.into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:58:12
+   |
+LL |       } else if b {
+   |  ____________^
+LL | |         0
+LL | |     } else {
+LL | |         1
+LL | |     };
+   | |_____^ help: replace with from: `{ i32::from(!b) }`
+   |
+   = note: `!b as i32` or `(!b).into()` can also be valid options
+
+error: boolean to int conversion using if
+  --> $DIR/bool_to_int_with_if.rs:116:5
+   |
+LL |     if a { 1 } else { 0 }
+   |     ^^^^^^^^^^^^^^^^^^^^^ help: replace with from: `u8::from(a)`
+   |
+   = note: `a as u8` or `a.into()` can also be valid options
+
+error: aborting due to 9 previous errors
+
diff --git a/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.rs b/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.rs
index 0d65071af15e..6f0485b5279b 100644
--- a/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.rs
+++ b/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.rs
@@ -14,31 +14,31 @@ fn is_rust_file(filename: &str) -> bool {
 
 fn main() {
     // std::string::String and &str should trigger the lint failure with .ext12
-    let _ = String::from("").ends_with(".ext12");
+    let _ = String::new().ends_with(".ext12");
     let _ = "str".ends_with(".ext12");
 
     // The test struct should not trigger the lint failure with .ext12
     TestStruct {}.ends_with(".ext12");
 
     // std::string::String and &str should trigger the lint failure with .EXT12
-    let _ = String::from("").ends_with(".EXT12");
+    let _ = String::new().ends_with(".EXT12");
     let _ = "str".ends_with(".EXT12");
 
     // The test struct should not trigger the lint failure with .EXT12
     TestStruct {}.ends_with(".EXT12");
 
     // Should not trigger the lint failure with .eXT12
-    let _ = String::from("").ends_with(".eXT12");
+    let _ = String::new().ends_with(".eXT12");
     let _ = "str".ends_with(".eXT12");
     TestStruct {}.ends_with(".eXT12");
 
     // Should not trigger the lint failure with .EXT123 (too long)
-    let _ = String::from("").ends_with(".EXT123");
+    let _ = String::new().ends_with(".EXT123");
     let _ = "str".ends_with(".EXT123");
     TestStruct {}.ends_with(".EXT123");
 
     // Shouldn't fail if it doesn't start with a dot
-    let _ = String::from("").ends_with("a.ext");
+    let _ = String::new().ends_with("a.ext");
     let _ = "str".ends_with("a.extA");
     TestStruct {}.ends_with("a.ext");
 }
diff --git a/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.stderr b/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.stderr
index 05b98169f2d1..5d9a043edb9a 100644
--- a/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.stderr
+++ b/src/tools/clippy/tests/ui/case_sensitive_file_extension_comparisons.stderr
@@ -8,10 +8,10 @@ LL |     filename.ends_with(".rs")
    = help: consider using a case-insensitive comparison instead
 
 error: case-sensitive file extension comparison
-  --> $DIR/case_sensitive_file_extension_comparisons.rs:17:30
+  --> $DIR/case_sensitive_file_extension_comparisons.rs:17:27
    |
-LL |     let _ = String::from("").ends_with(".ext12");
-   |                              ^^^^^^^^^^^^^^^^^^^
+LL |     let _ = String::new().ends_with(".ext12");
+   |                           ^^^^^^^^^^^^^^^^^^^
    |
    = help: consider using a case-insensitive comparison instead
 
@@ -24,10 +24,10 @@ LL |     let _ = "str".ends_with(".ext12");
    = help: consider using a case-insensitive comparison instead
 
 error: case-sensitive file extension comparison
-  --> $DIR/case_sensitive_file_extension_comparisons.rs:24:30
+  --> $DIR/case_sensitive_file_extension_comparisons.rs:24:27
    |
-LL |     let _ = String::from("").ends_with(".EXT12");
-   |                              ^^^^^^^^^^^^^^^^^^^
+LL |     let _ = String::new().ends_with(".EXT12");
+   |                           ^^^^^^^^^^^^^^^^^^^
    |
    = help: consider using a case-insensitive comparison instead
 
diff --git a/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.fixed b/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.fixed
new file mode 100644
index 000000000000..b70c19129511
--- /dev/null
+++ b/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.fixed
@@ -0,0 +1,24 @@
+// run-rustfix
+#![warn(clippy::cast_slice_from_raw_parts)]
+
+#[allow(unused_imports, unused_unsafe)]
+fn main() {
+    let mut vec = vec![0u8; 1];
+    let ptr: *const u8 = vec.as_ptr();
+    let mptr = vec.as_mut_ptr();
+    let _: *const [u8] = unsafe { core::ptr::slice_from_raw_parts(ptr, 1) };
+    let _: *const [u8] = unsafe { core::ptr::slice_from_raw_parts_mut(mptr, 1) };
+    let _: *const [u8] = core::ptr::slice_from_raw_parts(ptr, 1);
+    {
+        use core::slice;
+        let _: *const [u8] = core::ptr::slice_from_raw_parts(ptr, 1);
+        use slice as one;
+        let _: *const [u8] = core::ptr::slice_from_raw_parts(ptr, 1);
+    }
+    {
+        use std::slice;
+        let _: *const [u8] = core::ptr::slice_from_raw_parts(ptr, 1);
+        use slice as one;
+        let _: *const [u8] = core::ptr::slice_from_raw_parts(ptr, 1);
+    }
+}
diff --git a/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.rs b/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.rs
new file mode 100644
index 000000000000..c1b316765c96
--- /dev/null
+++ b/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.rs
@@ -0,0 +1,24 @@
+// run-rustfix
+#![warn(clippy::cast_slice_from_raw_parts)]
+
+#[allow(unused_imports, unused_unsafe)]
+fn main() {
+    let mut vec = vec![0u8; 1];
+    let ptr: *const u8 = vec.as_ptr();
+    let mptr = vec.as_mut_ptr();
+    let _: *const [u8] = unsafe { std::slice::from_raw_parts(ptr, 1) as *const [u8] };
+    let _: *const [u8] = unsafe { std::slice::from_raw_parts_mut(mptr, 1) as *mut [u8] };
+    let _: *const [u8] = unsafe { std::slice::from_raw_parts(ptr, 1) } as *const [u8];
+    {
+        use core::slice;
+        let _: *const [u8] = unsafe { slice::from_raw_parts(ptr, 1) } as *const [u8];
+        use slice as one;
+        let _: *const [u8] = unsafe { one::from_raw_parts(ptr, 1) } as *const [u8];
+    }
+    {
+        use std::slice;
+        let _: *const [u8] = unsafe { slice::from_raw_parts(ptr, 1) } as *const [u8];
+        use slice as one;
+        let _: *const [u8] = unsafe { one::from_raw_parts(ptr, 1) } as *const [u8];
+    }
+}
diff --git a/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.stderr b/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.stderr
new file mode 100644
index 000000000000..f07801c197cc
--- /dev/null
+++ b/src/tools/clippy/tests/ui/cast_raw_slice_pointer_cast.stderr
@@ -0,0 +1,46 @@
+error: casting the result of `from_raw_parts` to *const [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:9:35
+   |
+LL |     let _: *const [u8] = unsafe { std::slice::from_raw_parts(ptr, 1) as *const [u8] };
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts(ptr, 1)`
+   |
+   = note: `-D clippy::cast-slice-from-raw-parts` implied by `-D warnings`
+
+error: casting the result of `from_raw_parts_mut` to *mut [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:10:35
+   |
+LL |     let _: *const [u8] = unsafe { std::slice::from_raw_parts_mut(mptr, 1) as *mut [u8] };
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts_mut(mptr, 1)`
+
+error: casting the result of `from_raw_parts` to *const [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:11:26
+   |
+LL |     let _: *const [u8] = unsafe { std::slice::from_raw_parts(ptr, 1) } as *const [u8];
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts(ptr, 1)`
+
+error: casting the result of `from_raw_parts` to *const [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:14:30
+   |
+LL |         let _: *const [u8] = unsafe { slice::from_raw_parts(ptr, 1) } as *const [u8];
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts(ptr, 1)`
+
+error: casting the result of `from_raw_parts` to *const [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:16:30
+   |
+LL |         let _: *const [u8] = unsafe { one::from_raw_parts(ptr, 1) } as *const [u8];
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts(ptr, 1)`
+
+error: casting the result of `from_raw_parts` to *const [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:20:30
+   |
+LL |         let _: *const [u8] = unsafe { slice::from_raw_parts(ptr, 1) } as *const [u8];
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts(ptr, 1)`
+
+error: casting the result of `from_raw_parts` to *const [u8]
+  --> $DIR/cast_raw_slice_pointer_cast.rs:22:30
+   |
+LL |         let _: *const [u8] = unsafe { one::from_raw_parts(ptr, 1) } as *const [u8];
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `core::ptr::slice_from_raw_parts(ptr, 1)`
+
+error: aborting due to 7 previous errors
+
diff --git a/src/tools/clippy/tests/ui/collapsible_if.fixed b/src/tools/clippy/tests/ui/collapsible_if.fixed
index 5b0e4a473c4a..6bb7682bae95 100644
--- a/src/tools/clippy/tests/ui/collapsible_if.fixed
+++ b/src/tools/clippy/tests/ui/collapsible_if.fixed
@@ -139,6 +139,9 @@ fn main() {
     // Fix #5962
     if matches!(true, true) && matches!(true, true) {}
 
+    // Issue #9375
+    if matches!(true, true) && truth() && matches!(true, true) {}
+
     if true {
         #[cfg(not(teehee))]
         if true {
diff --git a/src/tools/clippy/tests/ui/collapsible_if.rs b/src/tools/clippy/tests/ui/collapsible_if.rs
index cd231a5d7abb..e216a9ee54c9 100644
--- a/src/tools/clippy/tests/ui/collapsible_if.rs
+++ b/src/tools/clippy/tests/ui/collapsible_if.rs
@@ -155,6 +155,11 @@ fn main() {
         if matches!(true, true) {}
     }
 
+    // Issue #9375
+    if matches!(true, true) && truth() {
+        if matches!(true, true) {}
+    }
+
     if true {
         #[cfg(not(teehee))]
         if true {
diff --git a/src/tools/clippy/tests/ui/collapsible_if.stderr b/src/tools/clippy/tests/ui/collapsible_if.stderr
index 6749612388fe..6327444df21d 100644
--- a/src/tools/clippy/tests/ui/collapsible_if.stderr
+++ b/src/tools/clippy/tests/ui/collapsible_if.stderr
@@ -126,5 +126,13 @@ LL | |         if matches!(true, true) {}
 LL | |     }
    | |_____^ help: collapse nested if block: `if matches!(true, true) && matches!(true, true) {}`
 
-error: aborting due to 8 previous errors
+error: this `if` statement can be collapsed
+  --> $DIR/collapsible_if.rs:159:5
+   |
+LL | /     if matches!(true, true) && truth() {
+LL | |         if matches!(true, true) {}
+LL | |     }
+   | |_____^ help: collapse nested if block: `if matches!(true, true) && truth() && matches!(true, true) {}`
+
+error: aborting due to 9 previous errors
 
diff --git a/src/tools/clippy/tests/ui/collapsible_str_replace.fixed b/src/tools/clippy/tests/ui/collapsible_str_replace.fixed
new file mode 100644
index 000000000000..49fc9a9629e2
--- /dev/null
+++ b/src/tools/clippy/tests/ui/collapsible_str_replace.fixed
@@ -0,0 +1,73 @@
+// run-rustfix
+
+#![warn(clippy::collapsible_str_replace)]
+
+fn get_filter() -> char {
+    'u'
+}
+
+fn main() {
+    let d = 'd';
+    let p = 'p';
+    let s = 's';
+    let u = 'u';
+    let l = "l";
+
+    let mut iter = ["l", "z"].iter();
+
+    // LINT CASES
+    let _ = "hesuo worpd".replace(['s', 'u'], "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u'], l);
+
+    let _ = "hesuo worpd".replace(['s', 'u', 'p'], "l");
+
+    let _ = "hesuo worpd"
+        .replace(['s', 'u', 'p', 'd'], "l");
+
+    let _ = "hesuo world".replace([s, 'u'], "l");
+
+    let _ = "hesuo worpd".replace([s, 'u', 'p'], "l");
+
+    let _ = "hesuo worpd".replace([s, u, 'p'], "l");
+
+    let _ = "hesuo worpd".replace([s, u, p], "l");
+
+    let _ = "hesuo worlp".replace(['s', 'u'], "l").replace('p', "d");
+
+    let _ = "hesuo worpd".replace('s', "x").replace(['u', 'p'], "l");
+
+    // Note: Future iterations could lint `replace(|c| matches!(c, "su" | 'd' | 'p'), "l")`
+    let _ = "hesudo worpd".replace("su", "l").replace(['d', 'p'], "l");
+
+    let _ = "hesudo worpd".replace([d, 'p'], "l").replace("su", "l");
+
+    let _ = "hesuo world".replace([get_filter(), 's'], "l");
+
+    // NO LINT CASES
+    let _ = "hesuo world".replace('s', "l").replace('u', "p");
+
+    let _ = "hesuo worpd".replace('s', "l").replace('p', l);
+
+    let _ = "hesudo worpd".replace('d', "l").replace("su", "l").replace('p', "l");
+
+    // Note: Future iterations of `collapsible_str_replace` might lint this and combine to `[s, u, p]`
+    let _ = "hesuo worpd".replace([s, u], "l").replace([u, p], "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u'], "l").replace(['u', 'p'], "l");
+
+    let _ = "hesuo worpd".replace('s', "l").replace(['u', 'p'], "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u', 'p'], "l").replace('r', "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u', 'p'], l).replace('r', l);
+
+    let _ = "hesuo worpd".replace(['s', u, 'p'], "l").replace('r', "l");
+
+    let _ = "hesuo worpd".replace([s, u], "l").replace(p, "l");
+
+    // Regression test
+    let _ = "hesuo worpd"
+        .replace('u', iter.next().unwrap())
+        .replace('s', iter.next().unwrap());
+}
diff --git a/src/tools/clippy/tests/ui/collapsible_str_replace.rs b/src/tools/clippy/tests/ui/collapsible_str_replace.rs
new file mode 100644
index 000000000000..e3e25c4146ff
--- /dev/null
+++ b/src/tools/clippy/tests/ui/collapsible_str_replace.rs
@@ -0,0 +1,76 @@
+// run-rustfix
+
+#![warn(clippy::collapsible_str_replace)]
+
+fn get_filter() -> char {
+    'u'
+}
+
+fn main() {
+    let d = 'd';
+    let p = 'p';
+    let s = 's';
+    let u = 'u';
+    let l = "l";
+
+    let mut iter = ["l", "z"].iter();
+
+    // LINT CASES
+    let _ = "hesuo worpd".replace('s', "l").replace('u', "l");
+
+    let _ = "hesuo worpd".replace('s', l).replace('u', l);
+
+    let _ = "hesuo worpd".replace('s', "l").replace('u', "l").replace('p', "l");
+
+    let _ = "hesuo worpd"
+        .replace('s', "l")
+        .replace('u', "l")
+        .replace('p', "l")
+        .replace('d', "l");
+
+    let _ = "hesuo world".replace(s, "l").replace('u', "l");
+
+    let _ = "hesuo worpd".replace(s, "l").replace('u', "l").replace('p', "l");
+
+    let _ = "hesuo worpd".replace(s, "l").replace(u, "l").replace('p', "l");
+
+    let _ = "hesuo worpd".replace(s, "l").replace(u, "l").replace(p, "l");
+
+    let _ = "hesuo worlp".replace('s', "l").replace('u', "l").replace('p', "d");
+
+    let _ = "hesuo worpd".replace('s', "x").replace('u', "l").replace('p', "l");
+
+    // Note: Future iterations could lint `replace(|c| matches!(c, "su" | 'd' | 'p'), "l")`
+    let _ = "hesudo worpd".replace("su", "l").replace('d', "l").replace('p', "l");
+
+    let _ = "hesudo worpd".replace(d, "l").replace('p', "l").replace("su", "l");
+
+    let _ = "hesuo world".replace(get_filter(), "l").replace('s', "l");
+
+    // NO LINT CASES
+    let _ = "hesuo world".replace('s', "l").replace('u', "p");
+
+    let _ = "hesuo worpd".replace('s', "l").replace('p', l);
+
+    let _ = "hesudo worpd".replace('d', "l").replace("su", "l").replace('p', "l");
+
+    // Note: Future iterations of `collapsible_str_replace` might lint this and combine to `[s, u, p]`
+    let _ = "hesuo worpd".replace([s, u], "l").replace([u, p], "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u'], "l").replace(['u', 'p'], "l");
+
+    let _ = "hesuo worpd".replace('s', "l").replace(['u', 'p'], "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u', 'p'], "l").replace('r', "l");
+
+    let _ = "hesuo worpd".replace(['s', 'u', 'p'], l).replace('r', l);
+
+    let _ = "hesuo worpd".replace(['s', u, 'p'], "l").replace('r', "l");
+
+    let _ = "hesuo worpd".replace([s, u], "l").replace(p, "l");
+
+    // Regression test
+    let _ = "hesuo worpd"
+        .replace('u', iter.next().unwrap())
+        .replace('s', iter.next().unwrap());
+}
diff --git a/src/tools/clippy/tests/ui/collapsible_str_replace.stderr b/src/tools/clippy/tests/ui/collapsible_str_replace.stderr
new file mode 100644
index 000000000000..8e3daf3b898a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/collapsible_str_replace.stderr
@@ -0,0 +1,86 @@
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:19:27
+   |
+LL |     let _ = "hesuo worpd".replace('s', "l").replace('u', "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace(['s', 'u'], "l")`
+   |
+   = note: `-D clippy::collapsible-str-replace` implied by `-D warnings`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:21:27
+   |
+LL |     let _ = "hesuo worpd".replace('s', l).replace('u', l);
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace(['s', 'u'], l)`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:23:27
+   |
+LL |     let _ = "hesuo worpd".replace('s', "l").replace('u', "l").replace('p', "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace(['s', 'u', 'p'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:26:10
+   |
+LL |           .replace('s', "l")
+   |  __________^
+LL | |         .replace('u', "l")
+LL | |         .replace('p', "l")
+LL | |         .replace('d', "l");
+   | |__________________________^ help: replace with: `replace(['s', 'u', 'p', 'd'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:31:27
+   |
+LL |     let _ = "hesuo world".replace(s, "l").replace('u', "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace([s, 'u'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:33:27
+   |
+LL |     let _ = "hesuo worpd".replace(s, "l").replace('u', "l").replace('p', "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace([s, 'u', 'p'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:35:27
+   |
+LL |     let _ = "hesuo worpd".replace(s, "l").replace(u, "l").replace('p', "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace([s, u, 'p'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:37:27
+   |
+LL |     let _ = "hesuo worpd".replace(s, "l").replace(u, "l").replace(p, "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace([s, u, p], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:39:27
+   |
+LL |     let _ = "hesuo worlp".replace('s', "l").replace('u', "l").replace('p', "d");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace(['s', 'u'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:41:45
+   |
+LL |     let _ = "hesuo worpd".replace('s', "x").replace('u', "l").replace('p', "l");
+   |                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace(['u', 'p'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:44:47
+   |
+LL |     let _ = "hesudo worpd".replace("su", "l").replace('d', "l").replace('p', "l");
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace(['d', 'p'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:46:28
+   |
+LL |     let _ = "hesudo worpd".replace(d, "l").replace('p', "l").replace("su", "l");
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace([d, 'p'], "l")`
+
+error: used consecutive `str::replace` call
+  --> $DIR/collapsible_str_replace.rs:48:27
+   |
+LL |     let _ = "hesuo world".replace(get_filter(), "l").replace('s', "l");
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `replace([get_filter(), 's'], "l")`
+
+error: aborting due to 13 previous errors
+
diff --git a/src/tools/clippy/tests/ui/crashes/ice-7126.rs b/src/tools/clippy/tests/ui/crashes/ice-7126.rs
index ca563ba09785..b2dc2248b556 100644
--- a/src/tools/clippy/tests/ui/crashes/ice-7126.rs
+++ b/src/tools/clippy/tests/ui/crashes/ice-7126.rs
@@ -1,13 +1,13 @@
 // This test requires a feature gated const fn and will stop working in the future.
 
-#![feature(const_btree_new)]
+#![feature(const_btree_len)]
 
 use std::collections::BTreeMap;
 
-struct Foo(BTreeMap<i32, i32>);
+struct Foo(usize);
 impl Foo {
     fn new() -> Self {
-        Self(BTreeMap::new())
+        Self(BTreeMap::len(&BTreeMap::<u8, u8>::new()))
     }
 }
 
diff --git a/src/tools/clippy/tests/ui/crashes/ice-9405.rs b/src/tools/clippy/tests/ui/crashes/ice-9405.rs
new file mode 100644
index 000000000000..e2d274aeb044
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-9405.rs
@@ -0,0 +1,11 @@
+#![warn(clippy::useless_format)]
+#![allow(clippy::print_literal)]
+
+fn main() {
+    println!(
+        "\
+
+            {}",
+        "multiple skipped lines"
+    );
+}
diff --git a/src/tools/clippy/tests/ui/crashes/ice-9405.stderr b/src/tools/clippy/tests/ui/crashes/ice-9405.stderr
new file mode 100644
index 000000000000..9a6e410f21ea
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-9405.stderr
@@ -0,0 +1,11 @@
+warning: multiple lines skipped by escaped newline
+  --> $DIR/ice-9405.rs:6:10
+   |
+LL |           "/
+   |  __________^
+LL | |
+LL | |             {}",
+   | |____________^ skipping everything up to and including this point
+
+warning: 1 warning emitted
+
diff --git a/src/tools/clippy/tests/ui/crashes/ice-9414.rs b/src/tools/clippy/tests/ui/crashes/ice-9414.rs
new file mode 100644
index 000000000000..02cf5d5c240f
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-9414.rs
@@ -0,0 +1,8 @@
+#![warn(clippy::result_large_err)]
+
+trait T {}
+fn f(_: &u32) -> Result<(), *const (dyn '_ + T)> {
+    Ok(())
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/crashes/ice-9463.rs b/src/tools/clippy/tests/ui/crashes/ice-9463.rs
new file mode 100644
index 000000000000..41ef930d3233
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-9463.rs
@@ -0,0 +1,5 @@
+#![deny(arithmetic_overflow, const_err)]
+fn main() {
+    let _x = -1_i32 >> -1;
+    let _y = 1u32 >> 10000000000000u32;
+}
diff --git a/src/tools/clippy/tests/ui/crashes/ice-9463.stderr b/src/tools/clippy/tests/ui/crashes/ice-9463.stderr
new file mode 100644
index 000000000000..7daa08aeb6c9
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-9463.stderr
@@ -0,0 +1,29 @@
+error: this arithmetic operation will overflow
+  --> $DIR/ice-9463.rs:3:14
+   |
+LL |     let _x = -1_i32 >> -1;
+   |              ^^^^^^^^^^^^ attempt to shift right by `-1_i32`, which would overflow
+   |
+note: the lint level is defined here
+  --> $DIR/ice-9463.rs:1:9
+   |
+LL | #![deny(arithmetic_overflow, const_err)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: this arithmetic operation will overflow
+  --> $DIR/ice-9463.rs:4:14
+   |
+LL |     let _y = 1u32 >> 10000000000000u32;
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ attempt to shift right by `1316134912_u32`, which would overflow
+
+error: literal out of range for `u32`
+  --> $DIR/ice-9463.rs:4:22
+   |
+LL |     let _y = 1u32 >> 10000000000000u32;
+   |                      ^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[deny(overflowing_literals)]` on by default
+   = note: the literal `10000000000000u32` does not fit into the type `u32` whose range is `0..=4294967295`
+
+error: aborting due to 3 previous errors
+
diff --git a/src/tools/clippy/tests/ui/derivable_impls.fixed b/src/tools/clippy/tests/ui/derivable_impls.fixed
new file mode 100644
index 000000000000..7dcdfb0937e8
--- /dev/null
+++ b/src/tools/clippy/tests/ui/derivable_impls.fixed
@@ -0,0 +1,213 @@
+// run-rustfix
+
+#![allow(dead_code)]
+
+use std::collections::HashMap;
+
+#[derive(Default)]
+struct FooDefault<'a> {
+    a: bool,
+    b: i32,
+    c: u64,
+    d: Vec<i32>,
+    e: FooND1,
+    f: FooND2,
+    g: HashMap<i32, i32>,
+    h: (i32, Vec<i32>),
+    i: [Vec<i32>; 3],
+    j: [i32; 5],
+    k: Option<i32>,
+    l: &'a [i32],
+}
+
+
+
+#[derive(Default)]
+struct TupleDefault(bool, i32, u64);
+
+
+
+struct FooND1 {
+    a: bool,
+}
+
+impl std::default::Default for FooND1 {
+    fn default() -> Self {
+        Self { a: true }
+    }
+}
+
+struct FooND2 {
+    a: i32,
+}
+
+impl std::default::Default for FooND2 {
+    fn default() -> Self {
+        Self { a: 5 }
+    }
+}
+
+struct FooNDNew {
+    a: bool,
+}
+
+impl FooNDNew {
+    fn new() -> Self {
+        Self { a: true }
+    }
+}
+
+impl Default for FooNDNew {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+struct FooNDVec(Vec<i32>);
+
+impl Default for FooNDVec {
+    fn default() -> Self {
+        Self(vec![5, 12])
+    }
+}
+
+#[derive(Default)]
+struct StrDefault<'a>(&'a str);
+
+
+
+#[derive(Default)]
+struct AlreadyDerived(i32, bool);
+
+macro_rules! mac {
+    () => {
+        0
+    };
+    ($e:expr) => {
+        struct X(u32);
+        impl Default for X {
+            fn default() -> Self {
+                Self($e)
+            }
+        }
+    };
+}
+
+mac!(0);
+
+#[derive(Default)]
+struct Y(u32);
+
+
+struct RustIssue26925<T> {
+    a: Option<T>,
+}
+
+// We should watch out for cases where a manual impl is needed because a
+// derive adds different type bounds (https://github.com/rust-lang/rust/issues/26925).
+// For example, a struct with Option<T> does not require T: Default, but a derive adds
+// that type bound anyways. So until #26925 get fixed we should disable lint
+// for the following case
+impl<T> Default for RustIssue26925<T> {
+    fn default() -> Self {
+        Self { a: None }
+    }
+}
+
+struct SpecializedImpl<A, B> {
+    a: A,
+    b: B,
+}
+
+impl<T: Default> Default for SpecializedImpl<T, T> {
+    fn default() -> Self {
+        Self {
+            a: T::default(),
+            b: T::default(),
+        }
+    }
+}
+
+#[derive(Default)]
+struct WithoutSelfCurly {
+    a: bool,
+}
+
+
+
+#[derive(Default)]
+struct WithoutSelfParan(bool);
+
+
+
+// https://github.com/rust-lang/rust-clippy/issues/7655
+
+pub struct SpecializedImpl2<T> {
+    v: Vec<T>,
+}
+
+impl Default for SpecializedImpl2<String> {
+    fn default() -> Self {
+        Self { v: Vec::new() }
+    }
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/7654
+
+pub struct Color {
+    pub r: u8,
+    pub g: u8,
+    pub b: u8,
+}
+
+/// `#000000`
+impl Default for Color {
+    fn default() -> Self {
+        Color { r: 0, g: 0, b: 0 }
+    }
+}
+
+pub struct Color2 {
+    pub r: u8,
+    pub g: u8,
+    pub b: u8,
+}
+
+impl Default for Color2 {
+    /// `#000000`
+    fn default() -> Self {
+        Self { r: 0, g: 0, b: 0 }
+    }
+}
+
+#[derive(Default)]
+pub struct RepeatDefault1 {
+    a: [i8; 32],
+}
+
+
+
+pub struct RepeatDefault2 {
+    a: [i8; 33],
+}
+
+impl Default for RepeatDefault2 {
+    fn default() -> Self {
+        RepeatDefault2 { a: [0; 33] }
+    }
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/7753
+
+pub enum IntOrString {
+    Int(i32),
+    String(String),
+}
+
+impl Default for IntOrString {
+    fn default() -> Self {
+        IntOrString::Int(0)
+    }
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/derivable_impls.rs b/src/tools/clippy/tests/ui/derivable_impls.rs
index a6412004726d..625cbcdde230 100644
--- a/src/tools/clippy/tests/ui/derivable_impls.rs
+++ b/src/tools/clippy/tests/ui/derivable_impls.rs
@@ -1,3 +1,7 @@
+// run-rustfix
+
+#![allow(dead_code)]
+
 use std::collections::HashMap;
 
 struct FooDefault<'a> {
diff --git a/src/tools/clippy/tests/ui/derivable_impls.stderr b/src/tools/clippy/tests/ui/derivable_impls.stderr
index 49fb471a2196..c1db5a58b1f5 100644
--- a/src/tools/clippy/tests/ui/derivable_impls.stderr
+++ b/src/tools/clippy/tests/ui/derivable_impls.stderr
@@ -1,5 +1,5 @@
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:18:1
+  --> $DIR/derivable_impls.rs:22:1
    |
 LL | / impl std::default::Default for FooDefault<'_> {
 LL | |     fn default() -> Self {
@@ -11,10 +11,14 @@ LL | | }
    | |_^
    |
    = note: `-D clippy::derivable-impls` implied by `-D warnings`
-   = help: try annotating `FooDefault` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:39:1
+  --> $DIR/derivable_impls.rs:43:1
    |
 LL | / impl std::default::Default for TupleDefault {
 LL | |     fn default() -> Self {
@@ -23,10 +27,14 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = help: try annotating `TupleDefault` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:91:1
+  --> $DIR/derivable_impls.rs:95:1
    |
 LL | / impl Default for StrDefault<'_> {
 LL | |     fn default() -> Self {
@@ -35,10 +43,14 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = help: try annotating `StrDefault` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:117:1
+  --> $DIR/derivable_impls.rs:121:1
    |
 LL | / impl Default for Y {
 LL | |     fn default() -> Self {
@@ -47,10 +59,14 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = help: try annotating `Y` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:156:1
+  --> $DIR/derivable_impls.rs:160:1
    |
 LL | / impl Default for WithoutSelfCurly {
 LL | |     fn default() -> Self {
@@ -59,10 +75,14 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = help: try annotating `WithoutSelfCurly` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:164:1
+  --> $DIR/derivable_impls.rs:168:1
    |
 LL | / impl Default for WithoutSelfParan {
 LL | |     fn default() -> Self {
@@ -71,10 +91,14 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = help: try annotating `WithoutSelfParan` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: this `impl` can be derived
-  --> $DIR/derivable_impls.rs:214:1
+  --> $DIR/derivable_impls.rs:218:1
    |
 LL | / impl Default for RepeatDefault1 {
 LL | |     fn default() -> Self {
@@ -83,7 +107,11 @@ LL | |     }
 LL | | }
    | |_^
    |
-   = help: try annotating `RepeatDefault1` with `#[derive(Default)]`
+   = help: remove the manual implementation...
+help: ...and instead derive it
+   |
+LL | #[derive(Default)]
+   |
 
 error: aborting due to 7 previous errors
 
diff --git a/src/tools/clippy/tests/ui/eprint_with_newline.rs b/src/tools/clippy/tests/ui/eprint_with_newline.rs
index 8df32649ad94..de5e121be877 100644
--- a/src/tools/clippy/tests/ui/eprint_with_newline.rs
+++ b/src/tools/clippy/tests/ui/eprint_with_newline.rs
@@ -45,5 +45,13 @@ fn main() {
     eprint!("\r\n");
     eprint!("foo\r\n");
     eprint!("\\r\n"); //~ ERROR
-    eprint!("foo\rbar\n") // ~ ERROR
+    eprint!("foo\rbar\n");
+
+    // Ignore expanded format strings
+    macro_rules! newline {
+        () => {
+            "\n"
+        };
+    }
+    eprint!(newline!());
 }
diff --git a/src/tools/clippy/tests/ui/eprint_with_newline.stderr b/src/tools/clippy/tests/ui/eprint_with_newline.stderr
index f137787bff0c..0eefb9f0ca97 100644
--- a/src/tools/clippy/tests/ui/eprint_with_newline.stderr
+++ b/src/tools/clippy/tests/ui/eprint_with_newline.stderr
@@ -83,7 +83,7 @@ LL | |     );
 help: use `eprintln!` instead
    |
 LL ~     eprintln!(
-LL ~         ""
+LL ~         
    |
 
 error: using `eprint!()` with a format string that ends in a single newline
@@ -98,7 +98,7 @@ LL | |     );
 help: use `eprintln!` instead
    |
 LL ~     eprintln!(
-LL ~         r""
+LL ~         
    |
 
 error: using `eprint!()` with a format string that ends in a single newline
@@ -113,17 +113,5 @@ LL -     eprint!("/r/n"); //~ ERROR
 LL +     eprintln!("/r"); //~ ERROR
    |
 
-error: using `eprint!()` with a format string that ends in a single newline
-  --> $DIR/eprint_with_newline.rs:48:5
-   |
-LL |     eprint!("foo/rbar/n") // ~ ERROR
-   |     ^^^^^^^^^^^^^^^^^^^^^
-   |
-help: use `eprintln!` instead
-   |
-LL -     eprint!("foo/rbar/n") // ~ ERROR
-LL +     eprintln!("foo/rbar") // ~ ERROR
-   |
-
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
diff --git a/src/tools/clippy/tests/ui/expect.rs b/src/tools/clippy/tests/ui/expect.rs
index 1073acf6f0cd..d742595e14d4 100644
--- a/src/tools/clippy/tests/ui/expect.rs
+++ b/src/tools/clippy/tests/ui/expect.rs
@@ -6,8 +6,9 @@ fn expect_option() {
 }
 
 fn expect_result() {
-    let res: Result<u8, ()> = Ok(0);
+    let res: Result<u8, u8> = Ok(0);
     let _ = res.expect("");
+    let _ = res.expect_err("");
 }
 
 fn main() {
diff --git a/src/tools/clippy/tests/ui/expect.stderr b/src/tools/clippy/tests/ui/expect.stderr
index ab28aac45563..904c09046452 100644
--- a/src/tools/clippy/tests/ui/expect.stderr
+++ b/src/tools/clippy/tests/ui/expect.stderr
@@ -15,5 +15,13 @@ LL |     let _ = res.expect("");
    |
    = help: if this value is an `Err`, it will panic
 
-error: aborting due to 2 previous errors
+error: used `expect_err()` on `a Result` value
+  --> $DIR/expect.rs:11:13
+   |
+LL |     let _ = res.expect_err("");
+   |             ^^^^^^^^^^^^^^^^^^
+   |
+   = help: if this value is an `Ok`, it will panic
+
+error: aborting due to 3 previous errors
 
diff --git a/src/tools/clippy/tests/ui/explicit_write.fixed b/src/tools/clippy/tests/ui/explicit_write.fixed
index 74d0e5290282..35283725619a 100644
--- a/src/tools/clippy/tests/ui/explicit_write.fixed
+++ b/src/tools/clippy/tests/ui/explicit_write.fixed
@@ -36,6 +36,8 @@ fn main() {
         eprintln!("with {} {}", 2, value);
         eprintln!("with {value}");
         eprintln!("macro arg {}", one!());
+        let width = 2;
+        eprintln!("{:w$}", value, w = width);
     }
     // these should not warn, different destination
     {
diff --git a/src/tools/clippy/tests/ui/explicit_write.rs b/src/tools/clippy/tests/ui/explicit_write.rs
index e7a698d3e012..be864a55b663 100644
--- a/src/tools/clippy/tests/ui/explicit_write.rs
+++ b/src/tools/clippy/tests/ui/explicit_write.rs
@@ -36,6 +36,8 @@ fn main() {
         writeln!(std::io::stderr(), "with {} {}", 2, value).unwrap();
         writeln!(std::io::stderr(), "with {value}").unwrap();
         writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();
+        let width = 2;
+        writeln!(std::io::stderr(), "{:w$}", value, w = width).unwrap();
     }
     // these should not warn, different destination
     {
diff --git a/src/tools/clippy/tests/ui/explicit_write.stderr b/src/tools/clippy/tests/ui/explicit_write.stderr
index 29ae0cdece24..ff05f4343d77 100644
--- a/src/tools/clippy/tests/ui/explicit_write.stderr
+++ b/src/tools/clippy/tests/ui/explicit_write.stderr
@@ -72,5 +72,11 @@ error: use of `writeln!(stderr(), ...).unwrap()`
 LL |         writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprintln!("macro arg {}", one!())`
 
-error: aborting due to 12 previous errors
+error: use of `writeln!(stderr(), ...).unwrap()`
+  --> $DIR/explicit_write.rs:40:9
+   |
+LL |         writeln!(std::io::stderr(), "{:w$}", value, w = width).unwrap();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprintln!("{:w$}", value, w = width)`
+
+error: aborting due to 13 previous errors
 
diff --git a/src/tools/clippy/tests/ui/floating_point_exp.fixed b/src/tools/clippy/tests/ui/floating_point_exp.fixed
index ae7805fdf018..c86a502d15f0 100644
--- a/src/tools/clippy/tests/ui/floating_point_exp.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_exp.fixed
@@ -5,6 +5,7 @@ fn main() {
     let x = 2f32;
     let _ = x.exp_m1();
     let _ = x.exp_m1() + 2.0;
+    let _ = (x as f32).exp_m1() + 2.0;
     // Cases where the lint shouldn't be applied
     let _ = x.exp() - 2.0;
     let _ = x.exp() - 1.0 * 2.0;
diff --git a/src/tools/clippy/tests/ui/floating_point_exp.rs b/src/tools/clippy/tests/ui/floating_point_exp.rs
index 27e0b9bcbc93..e59589f912a2 100644
--- a/src/tools/clippy/tests/ui/floating_point_exp.rs
+++ b/src/tools/clippy/tests/ui/floating_point_exp.rs
@@ -5,6 +5,7 @@ fn main() {
     let x = 2f32;
     let _ = x.exp() - 1.0;
     let _ = x.exp() - 1.0 + 2.0;
+    let _ = (x as f32).exp() - 1.0 + 2.0;
     // Cases where the lint shouldn't be applied
     let _ = x.exp() - 2.0;
     let _ = x.exp() - 1.0 * 2.0;
diff --git a/src/tools/clippy/tests/ui/floating_point_exp.stderr b/src/tools/clippy/tests/ui/floating_point_exp.stderr
index 5cd999ad47cd..f84eede19872 100644
--- a/src/tools/clippy/tests/ui/floating_point_exp.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_exp.stderr
@@ -13,16 +13,22 @@ LL |     let _ = x.exp() - 1.0 + 2.0;
    |             ^^^^^^^^^^^^^ help: consider using: `x.exp_m1()`
 
 error: (e.pow(x) - 1) can be computed more accurately
-  --> $DIR/floating_point_exp.rs:13:13
+  --> $DIR/floating_point_exp.rs:8:13
+   |
+LL |     let _ = (x as f32).exp() - 1.0 + 2.0;
+   |             ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).exp_m1()`
+
+error: (e.pow(x) - 1) can be computed more accurately
+  --> $DIR/floating_point_exp.rs:14:13
    |
 LL |     let _ = x.exp() - 1.0;
    |             ^^^^^^^^^^^^^ help: consider using: `x.exp_m1()`
 
 error: (e.pow(x) - 1) can be computed more accurately
-  --> $DIR/floating_point_exp.rs:14:13
+  --> $DIR/floating_point_exp.rs:15:13
    |
 LL |     let _ = x.exp() - 1.0 + 2.0;
    |             ^^^^^^^^^^^^^ help: consider using: `x.exp_m1()`
 
-error: aborting due to 4 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/tools/clippy/tests/ui/floating_point_log.fixed b/src/tools/clippy/tests/ui/floating_point_log.fixed
index 5b487bb8fcf7..4def9300bb7d 100644
--- a/src/tools/clippy/tests/ui/floating_point_log.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_log.fixed
@@ -12,6 +12,7 @@ fn check_log_base() {
     let _ = x.ln();
     let _ = x.log2();
     let _ = x.ln();
+    let _ = (x as f32).log2();
 
     let x = 1f64;
     let _ = x.log2();
diff --git a/src/tools/clippy/tests/ui/floating_point_log.rs b/src/tools/clippy/tests/ui/floating_point_log.rs
index 01181484e7de..1e04caa7d2a8 100644
--- a/src/tools/clippy/tests/ui/floating_point_log.rs
+++ b/src/tools/clippy/tests/ui/floating_point_log.rs
@@ -12,6 +12,7 @@ fn check_log_base() {
     let _ = x.log(std::f32::consts::E);
     let _ = x.log(TWO);
     let _ = x.log(E);
+    let _ = (x as f32).log(2f32);
 
     let x = 1f64;
     let _ = x.log(2f64);
diff --git a/src/tools/clippy/tests/ui/floating_point_log.stderr b/src/tools/clippy/tests/ui/floating_point_log.stderr
index 96e5a1544417..89800a13a6ec 100644
--- a/src/tools/clippy/tests/ui/floating_point_log.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_log.stderr
@@ -31,25 +31,31 @@ LL |     let _ = x.log(E);
    |             ^^^^^^^^ help: consider using: `x.ln()`
 
 error: logarithm for bases 2, 10 and e can be computed more accurately
-  --> $DIR/floating_point_log.rs:17:13
+  --> $DIR/floating_point_log.rs:15:13
+   |
+LL |     let _ = (x as f32).log(2f32);
+   |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).log2()`
+
+error: logarithm for bases 2, 10 and e can be computed more accurately
+  --> $DIR/floating_point_log.rs:18:13
    |
 LL |     let _ = x.log(2f64);
    |             ^^^^^^^^^^^ help: consider using: `x.log2()`
 
 error: logarithm for bases 2, 10 and e can be computed more accurately
-  --> $DIR/floating_point_log.rs:18:13
+  --> $DIR/floating_point_log.rs:19:13
    |
 LL |     let _ = x.log(10f64);
    |             ^^^^^^^^^^^^ help: consider using: `x.log10()`
 
 error: logarithm for bases 2, 10 and e can be computed more accurately
-  --> $DIR/floating_point_log.rs:19:13
+  --> $DIR/floating_point_log.rs:20:13
    |
 LL |     let _ = x.log(std::f64::consts::E);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.ln()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:24:13
+  --> $DIR/floating_point_log.rs:25:13
    |
 LL |     let _ = (1f32 + 2.).ln();
    |             ^^^^^^^^^^^^^^^^ help: consider using: `2.0f32.ln_1p()`
@@ -57,118 +63,118 @@ LL |     let _ = (1f32 + 2.).ln();
    = note: `-D clippy::imprecise-flops` implied by `-D warnings`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:25:13
+  --> $DIR/floating_point_log.rs:26:13
    |
 LL |     let _ = (1f32 + 2.0).ln();
    |             ^^^^^^^^^^^^^^^^^ help: consider using: `2.0f32.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:26:13
+  --> $DIR/floating_point_log.rs:27:13
    |
 LL |     let _ = (1.0 + x).ln();
    |             ^^^^^^^^^^^^^^ help: consider using: `x.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:27:13
+  --> $DIR/floating_point_log.rs:28:13
    |
 LL |     let _ = (1.0 + x / 2.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x / 2.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:28:13
+  --> $DIR/floating_point_log.rs:29:13
    |
 LL |     let _ = (1.0 + x.powi(3)).ln();
    |             ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:29:13
+  --> $DIR/floating_point_log.rs:30:13
    |
 LL |     let _ = (1.0 + x.powi(3) / 2.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x.powi(3) / 2.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:30:13
+  --> $DIR/floating_point_log.rs:31:13
    |
 LL |     let _ = (1.0 + (std::f32::consts::E - 1.0)).ln();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(std::f32::consts::E - 1.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:31:13
+  --> $DIR/floating_point_log.rs:32:13
    |
 LL |     let _ = (x + 1.0).ln();
    |             ^^^^^^^^^^^^^^ help: consider using: `x.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:32:13
+  --> $DIR/floating_point_log.rs:33:13
    |
 LL |     let _ = (x.powi(3) + 1.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:33:13
+  --> $DIR/floating_point_log.rs:34:13
    |
 LL |     let _ = (x + 2.0 + 1.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x + 2.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:34:13
+  --> $DIR/floating_point_log.rs:35:13
    |
 LL |     let _ = (x / 2.0 + 1.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x / 2.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:42:13
+  --> $DIR/floating_point_log.rs:43:13
    |
 LL |     let _ = (1f64 + 2.).ln();
    |             ^^^^^^^^^^^^^^^^ help: consider using: `2.0f64.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:43:13
+  --> $DIR/floating_point_log.rs:44:13
    |
 LL |     let _ = (1f64 + 2.0).ln();
    |             ^^^^^^^^^^^^^^^^^ help: consider using: `2.0f64.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:44:13
+  --> $DIR/floating_point_log.rs:45:13
    |
 LL |     let _ = (1.0 + x).ln();
    |             ^^^^^^^^^^^^^^ help: consider using: `x.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:45:13
+  --> $DIR/floating_point_log.rs:46:13
    |
 LL |     let _ = (1.0 + x / 2.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x / 2.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:46:13
+  --> $DIR/floating_point_log.rs:47:13
    |
 LL |     let _ = (1.0 + x.powi(3)).ln();
    |             ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:47:13
+  --> $DIR/floating_point_log.rs:48:13
    |
 LL |     let _ = (x + 1.0).ln();
    |             ^^^^^^^^^^^^^^ help: consider using: `x.ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:48:13
+  --> $DIR/floating_point_log.rs:49:13
    |
 LL |     let _ = (x.powi(3) + 1.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(3).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:49:13
+  --> $DIR/floating_point_log.rs:50:13
    |
 LL |     let _ = (x + 2.0 + 1.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x + 2.0).ln_1p()`
 
 error: ln(1 + x) can be computed more accurately
-  --> $DIR/floating_point_log.rs:50:13
+  --> $DIR/floating_point_log.rs:51:13
    |
 LL |     let _ = (x / 2.0 + 1.0).ln();
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x / 2.0).ln_1p()`
 
-error: aborting due to 28 previous errors
+error: aborting due to 29 previous errors
 
diff --git a/src/tools/clippy/tests/ui/floating_point_logbase.fixed b/src/tools/clippy/tests/ui/floating_point_logbase.fixed
index 13962a272d45..936462f94066 100644
--- a/src/tools/clippy/tests/ui/floating_point_logbase.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_logbase.fixed
@@ -5,6 +5,7 @@ fn main() {
     let x = 3f32;
     let y = 5f32;
     let _ = x.log(y);
+    let _ = (x as f32).log(y);
     let _ = x.log(y);
     let _ = x.log(y);
     let _ = x.log(y);
diff --git a/src/tools/clippy/tests/ui/floating_point_logbase.rs b/src/tools/clippy/tests/ui/floating_point_logbase.rs
index 26bc20d5370b..0b56fa8fa41f 100644
--- a/src/tools/clippy/tests/ui/floating_point_logbase.rs
+++ b/src/tools/clippy/tests/ui/floating_point_logbase.rs
@@ -5,6 +5,7 @@ fn main() {
     let x = 3f32;
     let y = 5f32;
     let _ = x.ln() / y.ln();
+    let _ = (x as f32).ln() / y.ln();
     let _ = x.log2() / y.log2();
     let _ = x.log10() / y.log10();
     let _ = x.log(5f32) / y.log(5f32);
diff --git a/src/tools/clippy/tests/ui/floating_point_logbase.stderr b/src/tools/clippy/tests/ui/floating_point_logbase.stderr
index 78354c2f62d4..384e3554cbbe 100644
--- a/src/tools/clippy/tests/ui/floating_point_logbase.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_logbase.stderr
@@ -9,20 +9,26 @@ LL |     let _ = x.ln() / y.ln();
 error: log base can be expressed more clearly
   --> $DIR/floating_point_logbase.rs:8:13
    |
+LL |     let _ = (x as f32).ln() / y.ln();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).log(y)`
+
+error: log base can be expressed more clearly
+  --> $DIR/floating_point_logbase.rs:9:13
+   |
 LL |     let _ = x.log2() / y.log2();
    |             ^^^^^^^^^^^^^^^^^^^ help: consider using: `x.log(y)`
 
 error: log base can be expressed more clearly
-  --> $DIR/floating_point_logbase.rs:9:13
+  --> $DIR/floating_point_logbase.rs:10:13
    |
 LL |     let _ = x.log10() / y.log10();
    |             ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.log(y)`
 
 error: log base can be expressed more clearly
-  --> $DIR/floating_point_logbase.rs:10:13
+  --> $DIR/floating_point_logbase.rs:11:13
    |
 LL |     let _ = x.log(5f32) / y.log(5f32);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.log(y)`
 
-error: aborting due to 4 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/tools/clippy/tests/ui/floating_point_powf.fixed b/src/tools/clippy/tests/ui/floating_point_powf.fixed
index b0641a100cdc..e7ef45634dff 100644
--- a/src/tools/clippy/tests/ui/floating_point_powf.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_powf.fixed
@@ -11,10 +11,18 @@ fn main() {
     let _ = (-3.1f32).exp();
     let _ = x.sqrt();
     let _ = x.cbrt();
+    let _ = (x as f32).cbrt();
     let _ = x.powi(3);
     let _ = x.powi(-2);
     let _ = x.powi(16_777_215);
     let _ = x.powi(-16_777_215);
+    let _ = (x as f32).powi(-16_777_215);
+    let _ = (x as f32).powi(3);
+    let _ = (1.5_f32 + 1.0).cbrt();
+    let _ = 1.5_f64.cbrt();
+    let _ = 1.5_f64.sqrt();
+    let _ = 1.5_f64.powi(3);
+
     // Cases where the lint shouldn't be applied
     let _ = x.powf(2.1);
     let _ = x.powf(-2.1);
diff --git a/src/tools/clippy/tests/ui/floating_point_powf.rs b/src/tools/clippy/tests/ui/floating_point_powf.rs
index a0a2c973900f..d749aa2d48a4 100644
--- a/src/tools/clippy/tests/ui/floating_point_powf.rs
+++ b/src/tools/clippy/tests/ui/floating_point_powf.rs
@@ -11,10 +11,18 @@ fn main() {
     let _ = std::f32::consts::E.powf(-3.1);
     let _ = x.powf(1.0 / 2.0);
     let _ = x.powf(1.0 / 3.0);
+    let _ = (x as f32).powf(1.0 / 3.0);
     let _ = x.powf(3.0);
     let _ = x.powf(-2.0);
     let _ = x.powf(16_777_215.0);
     let _ = x.powf(-16_777_215.0);
+    let _ = (x as f32).powf(-16_777_215.0);
+    let _ = (x as f32).powf(3.0);
+    let _ = (1.5_f32 + 1.0).powf(1.0 / 3.0);
+    let _ = 1.5_f64.powf(1.0 / 3.0);
+    let _ = 1.5_f64.powf(1.0 / 2.0);
+    let _ = 1.5_f64.powf(3.0);
+
     // Cases where the lint shouldn't be applied
     let _ = x.powf(2.1);
     let _ = x.powf(-2.1);
diff --git a/src/tools/clippy/tests/ui/floating_point_powf.stderr b/src/tools/clippy/tests/ui/floating_point_powf.stderr
index 2422eb911e90..e9693de8fc90 100644
--- a/src/tools/clippy/tests/ui/floating_point_powf.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_powf.stderr
@@ -50,101 +50,143 @@ LL |     let _ = x.powf(1.0 / 3.0);
    |
    = note: `-D clippy::imprecise-flops` implied by `-D warnings`
 
-error: exponentiation with integer powers can be computed more efficiently
+error: cube-root of a number can be computed more accurately
   --> $DIR/floating_point_powf.rs:14:13
    |
+LL |     let _ = (x as f32).powf(1.0 / 3.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).cbrt()`
+
+error: exponentiation with integer powers can be computed more efficiently
+  --> $DIR/floating_point_powf.rs:15:13
+   |
 LL |     let _ = x.powf(3.0);
    |             ^^^^^^^^^^^ help: consider using: `x.powi(3)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:15:13
+  --> $DIR/floating_point_powf.rs:16:13
    |
 LL |     let _ = x.powf(-2.0);
    |             ^^^^^^^^^^^^ help: consider using: `x.powi(-2)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:16:13
+  --> $DIR/floating_point_powf.rs:17:13
    |
 LL |     let _ = x.powf(16_777_215.0);
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(16_777_215)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:17:13
+  --> $DIR/floating_point_powf.rs:18:13
    |
 LL |     let _ = x.powf(-16_777_215.0);
    |             ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(-16_777_215)`
 
+error: exponentiation with integer powers can be computed more efficiently
+  --> $DIR/floating_point_powf.rs:19:13
+   |
+LL |     let _ = (x as f32).powf(-16_777_215.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).powi(-16_777_215)`
+
+error: exponentiation with integer powers can be computed more efficiently
+  --> $DIR/floating_point_powf.rs:20:13
+   |
+LL |     let _ = (x as f32).powf(3.0);
+   |             ^^^^^^^^^^^^^^^^^^^^ help: consider using: `(x as f32).powi(3)`
+
+error: cube-root of a number can be computed more accurately
+  --> $DIR/floating_point_powf.rs:21:13
+   |
+LL |     let _ = (1.5_f32 + 1.0).powf(1.0 / 3.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(1.5_f32 + 1.0).cbrt()`
+
+error: cube-root of a number can be computed more accurately
+  --> $DIR/floating_point_powf.rs:22:13
+   |
+LL |     let _ = 1.5_f64.powf(1.0 / 3.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `1.5_f64.cbrt()`
+
+error: square-root of a number can be computed more efficiently and accurately
+  --> $DIR/floating_point_powf.rs:23:13
+   |
+LL |     let _ = 1.5_f64.powf(1.0 / 2.0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `1.5_f64.sqrt()`
+
+error: exponentiation with integer powers can be computed more efficiently
+  --> $DIR/floating_point_powf.rs:24:13
+   |
+LL |     let _ = 1.5_f64.powf(3.0);
+   |             ^^^^^^^^^^^^^^^^^ help: consider using: `1.5_f64.powi(3)`
+
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:25:13
+  --> $DIR/floating_point_powf.rs:33:13
    |
 LL |     let _ = 2f64.powf(x);
    |             ^^^^^^^^^^^^ help: consider using: `x.exp2()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:26:13
+  --> $DIR/floating_point_powf.rs:34:13
    |
 LL |     let _ = 2f64.powf(3.1);
    |             ^^^^^^^^^^^^^^ help: consider using: `3.1f64.exp2()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:27:13
+  --> $DIR/floating_point_powf.rs:35:13
    |
 LL |     let _ = 2f64.powf(-3.1);
    |             ^^^^^^^^^^^^^^^ help: consider using: `(-3.1f64).exp2()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:28:13
+  --> $DIR/floating_point_powf.rs:36:13
    |
 LL |     let _ = std::f64::consts::E.powf(x);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.exp()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:29:13
+  --> $DIR/floating_point_powf.rs:37:13
    |
 LL |     let _ = std::f64::consts::E.powf(3.1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `3.1f64.exp()`
 
 error: exponent for bases 2 and e can be computed more accurately
-  --> $DIR/floating_point_powf.rs:30:13
+  --> $DIR/floating_point_powf.rs:38:13
    |
 LL |     let _ = std::f64::consts::E.powf(-3.1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(-3.1f64).exp()`
 
 error: square-root of a number can be computed more efficiently and accurately
-  --> $DIR/floating_point_powf.rs:31:13
+  --> $DIR/floating_point_powf.rs:39:13
    |
 LL |     let _ = x.powf(1.0 / 2.0);
    |             ^^^^^^^^^^^^^^^^^ help: consider using: `x.sqrt()`
 
 error: cube-root of a number can be computed more accurately
-  --> $DIR/floating_point_powf.rs:32:13
+  --> $DIR/floating_point_powf.rs:40:13
    |
 LL |     let _ = x.powf(1.0 / 3.0);
    |             ^^^^^^^^^^^^^^^^^ help: consider using: `x.cbrt()`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:33:13
+  --> $DIR/floating_point_powf.rs:41:13
    |
 LL |     let _ = x.powf(3.0);
    |             ^^^^^^^^^^^ help: consider using: `x.powi(3)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:34:13
+  --> $DIR/floating_point_powf.rs:42:13
    |
 LL |     let _ = x.powf(-2.0);
    |             ^^^^^^^^^^^^ help: consider using: `x.powi(-2)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:35:13
+  --> $DIR/floating_point_powf.rs:43:13
    |
 LL |     let _ = x.powf(-2_147_483_648.0);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(-2_147_483_648)`
 
 error: exponentiation with integer powers can be computed more efficiently
-  --> $DIR/floating_point_powf.rs:36:13
+  --> $DIR/floating_point_powf.rs:44:13
    |
 LL |     let _ = x.powf(2_147_483_647.0);
    |             ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.powi(2_147_483_647)`
 
-error: aborting due to 24 previous errors
+error: aborting due to 31 previous errors
 
diff --git a/src/tools/clippy/tests/ui/floating_point_powi.fixed b/src/tools/clippy/tests/ui/floating_point_powi.fixed
index 85f7c531e398..5758db7c6c82 100644
--- a/src/tools/clippy/tests/ui/floating_point_powi.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_powi.fixed
@@ -8,6 +8,7 @@ fn main() {
     let y = 4f32;
     let _ = x.mul_add(x, y);
     let _ = y.mul_add(y, x);
+    let _ = (y as f32).mul_add(y as f32, x);
     let _ = x.mul_add(x, y).sqrt();
     let _ = y.mul_add(y, x).sqrt();
     // Cases where the lint shouldn't be applied
diff --git a/src/tools/clippy/tests/ui/floating_point_powi.rs b/src/tools/clippy/tests/ui/floating_point_powi.rs
index ece61d1bec42..5926bf1b0004 100644
--- a/src/tools/clippy/tests/ui/floating_point_powi.rs
+++ b/src/tools/clippy/tests/ui/floating_point_powi.rs
@@ -8,6 +8,7 @@ fn main() {
     let y = 4f32;
     let _ = x.powi(2) + y;
     let _ = x + y.powi(2);
+    let _ = x + (y as f32).powi(2);
     let _ = (x.powi(2) + y).sqrt();
     let _ = (x + y.powi(2)).sqrt();
     // Cases where the lint shouldn't be applied
diff --git a/src/tools/clippy/tests/ui/floating_point_powi.stderr b/src/tools/clippy/tests/ui/floating_point_powi.stderr
index 37d840988bb2..a3c74544212b 100644
--- a/src/tools/clippy/tests/ui/floating_point_powi.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_powi.stderr
@@ -15,14 +15,20 @@ LL |     let _ = x + y.powi(2);
 error: multiply and add expressions can be calculated more efficiently and accurately
   --> $DIR/floating_point_powi.rs:11:13
    |
-LL |     let _ = (x.powi(2) + y).sqrt();
-   |             ^^^^^^^^^^^^^^^ help: consider using: `x.mul_add(x, y)`
+LL |     let _ = x + (y as f32).powi(2);
+   |             ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(y as f32).mul_add(y as f32, x)`
 
 error: multiply and add expressions can be calculated more efficiently and accurately
   --> $DIR/floating_point_powi.rs:12:13
    |
+LL |     let _ = (x.powi(2) + y).sqrt();
+   |             ^^^^^^^^^^^^^^^ help: consider using: `x.mul_add(x, y)`
+
+error: multiply and add expressions can be calculated more efficiently and accurately
+  --> $DIR/floating_point_powi.rs:13:13
+   |
 LL |     let _ = (x + y.powi(2)).sqrt();
    |             ^^^^^^^^^^^^^^^ help: consider using: `y.mul_add(y, x)`
 
-error: aborting due to 4 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/tools/clippy/tests/ui/floating_point_rad.fixed b/src/tools/clippy/tests/ui/floating_point_rad.fixed
index ce91fe176c6f..27674b8a455b 100644
--- a/src/tools/clippy/tests/ui/floating_point_rad.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_rad.fixed
@@ -8,6 +8,11 @@ pub const fn const_context() {
     let _ = x * 180f32 / std::f32::consts::PI;
 }
 
+pub fn issue9391(degrees: i64) {
+    let _ = (degrees as f64).to_radians();
+    let _ = (degrees as f64).to_degrees();
+}
+
 fn main() {
     let x = 3f32;
     let _ = x.to_degrees();
diff --git a/src/tools/clippy/tests/ui/floating_point_rad.rs b/src/tools/clippy/tests/ui/floating_point_rad.rs
index 8f3234986148..f1ea73df3984 100644
--- a/src/tools/clippy/tests/ui/floating_point_rad.rs
+++ b/src/tools/clippy/tests/ui/floating_point_rad.rs
@@ -8,6 +8,11 @@ pub const fn const_context() {
     let _ = x * 180f32 / std::f32::consts::PI;
 }
 
+pub fn issue9391(degrees: i64) {
+    let _ = degrees as f64 * std::f64::consts::PI / 180.0;
+    let _ = degrees as f64 * 180.0 / std::f64::consts::PI;
+}
+
 fn main() {
     let x = 3f32;
     let _ = x * 180f32 / std::f32::consts::PI;
diff --git a/src/tools/clippy/tests/ui/floating_point_rad.stderr b/src/tools/clippy/tests/ui/floating_point_rad.stderr
index f12d3d23f3ab..979442f2c24a 100644
--- a/src/tools/clippy/tests/ui/floating_point_rad.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_rad.stderr
@@ -1,40 +1,52 @@
-error: conversion to degrees can be done more accurately
-  --> $DIR/floating_point_rad.rs:13:13
+error: conversion to radians can be done more accurately
+  --> $DIR/floating_point_rad.rs:12:13
    |
-LL |     let _ = x * 180f32 / std::f32::consts::PI;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.to_degrees()`
+LL |     let _ = degrees as f64 * std::f64::consts::PI / 180.0;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(degrees as f64).to_radians()`
    |
    = note: `-D clippy::suboptimal-flops` implied by `-D warnings`
 
 error: conversion to degrees can be done more accurately
-  --> $DIR/floating_point_rad.rs:14:13
+  --> $DIR/floating_point_rad.rs:13:13
+   |
+LL |     let _ = degrees as f64 * 180.0 / std::f64::consts::PI;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `(degrees as f64).to_degrees()`
+
+error: conversion to degrees can be done more accurately
+  --> $DIR/floating_point_rad.rs:18:13
+   |
+LL |     let _ = x * 180f32 / std::f32::consts::PI;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.to_degrees()`
+
+error: conversion to degrees can be done more accurately
+  --> $DIR/floating_point_rad.rs:19:13
    |
 LL |     let _ = 90. * 180f64 / std::f64::consts::PI;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.0_f64.to_degrees()`
 
 error: conversion to degrees can be done more accurately
-  --> $DIR/floating_point_rad.rs:15:13
+  --> $DIR/floating_point_rad.rs:20:13
    |
 LL |     let _ = 90.5 * 180f64 / std::f64::consts::PI;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.5_f64.to_degrees()`
 
 error: conversion to radians can be done more accurately
-  --> $DIR/floating_point_rad.rs:16:13
+  --> $DIR/floating_point_rad.rs:21:13
    |
 LL |     let _ = x * std::f32::consts::PI / 180f32;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.to_radians()`
 
 error: conversion to radians can be done more accurately
-  --> $DIR/floating_point_rad.rs:17:13
+  --> $DIR/floating_point_rad.rs:22:13
    |
 LL |     let _ = 90. * std::f32::consts::PI / 180f32;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.0_f64.to_radians()`
 
 error: conversion to radians can be done more accurately
-  --> $DIR/floating_point_rad.rs:18:13
+  --> $DIR/floating_point_rad.rs:23:13
    |
 LL |     let _ = 90.5 * std::f32::consts::PI / 180f32;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.5_f64.to_radians()`
 
-error: aborting due to 6 previous errors
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/format.fixed b/src/tools/clippy/tests/ui/format.fixed
index 6b754f3bd710..e0c5f692740a 100644
--- a/src/tools/clippy/tests/ui/format.fixed
+++ b/src/tools/clippy/tests/ui/format.fixed
@@ -28,18 +28,14 @@ fn main() {
     format!("{:?}", "foo"); // Don't warn about `Debug`.
     format!("{:8}", "foo");
     format!("{:width$}", "foo", width = 8);
-    "foo".to_string(); // Warn when the format makes no difference.
-    "foo".to_string(); // Warn when the format makes no difference.
     format!("foo {}", "bar");
     format!("{} bar", "foo");
 
-    let arg: String = "".to_owned();
+    let arg = String::new();
     arg.to_string();
     format!("{:?}", arg); // Don't warn about debug.
     format!("{:8}", arg);
     format!("{:width$}", arg, width = 8);
-    arg.to_string(); // Warn when the format makes no difference.
-    arg.to_string(); // Warn when the format makes no difference.
     format!("foo {}", arg);
     format!("{} bar", arg);
 
diff --git a/src/tools/clippy/tests/ui/format.rs b/src/tools/clippy/tests/ui/format.rs
index ca9826b356ec..ff83cd64bf09 100644
--- a/src/tools/clippy/tests/ui/format.rs
+++ b/src/tools/clippy/tests/ui/format.rs
@@ -30,18 +30,14 @@ fn main() {
     format!("{:?}", "foo"); // Don't warn about `Debug`.
     format!("{:8}", "foo");
     format!("{:width$}", "foo", width = 8);
-    format!("{:+}", "foo"); // Warn when the format makes no difference.
-    format!("{:<}", "foo"); // Warn when the format makes no difference.
     format!("foo {}", "bar");
     format!("{} bar", "foo");
 
-    let arg: String = "".to_owned();
+    let arg = String::new();
     format!("{}", arg);
     format!("{:?}", arg); // Don't warn about debug.
     format!("{:8}", arg);
     format!("{:width$}", arg, width = 8);
-    format!("{:+}", arg); // Warn when the format makes no difference.
-    format!("{:<}", arg); // Warn when the format makes no difference.
     format!("foo {}", arg);
     format!("{} bar", arg);
 
diff --git a/src/tools/clippy/tests/ui/format.stderr b/src/tools/clippy/tests/ui/format.stderr
index 6c35caeb034d..0ef0ac655d39 100644
--- a/src/tools/clippy/tests/ui/format.stderr
+++ b/src/tools/clippy/tests/ui/format.stderr
@@ -46,82 +46,58 @@ LL |     format!("{}", "foo");
    |     ^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `"foo".to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:33:5
-   |
-LL |     format!("{:+}", "foo"); // Warn when the format makes no difference.
-   |     ^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `"foo".to_string()`
-
-error: useless use of `format!`
-  --> $DIR/format.rs:34:5
-   |
-LL |     format!("{:<}", "foo"); // Warn when the format makes no difference.
-   |     ^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `"foo".to_string()`
-
-error: useless use of `format!`
-  --> $DIR/format.rs:39:5
+  --> $DIR/format.rs:37:5
    |
 LL |     format!("{}", arg);
    |     ^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `arg.to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:43:5
-   |
-LL |     format!("{:+}", arg); // Warn when the format makes no difference.
-   |     ^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `arg.to_string()`
-
-error: useless use of `format!`
-  --> $DIR/format.rs:44:5
-   |
-LL |     format!("{:<}", arg); // Warn when the format makes no difference.
-   |     ^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `arg.to_string()`
-
-error: useless use of `format!`
-  --> $DIR/format.rs:71:5
+  --> $DIR/format.rs:67:5
    |
 LL |     format!("{}", 42.to_string());
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `42.to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:73:5
+  --> $DIR/format.rs:69:5
    |
 LL |     format!("{}", x.display().to_string());
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `x.display().to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:77:18
+  --> $DIR/format.rs:73:18
    |
 LL |     let _ = Some(format!("{}", a + "bar"));
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `a + "bar"`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:81:22
+  --> $DIR/format.rs:77:22
    |
 LL |     let _s: String = format!("{}", &*v.join("/n"));
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `(&*v.join("/n")).to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:87:13
+  --> $DIR/format.rs:83:13
    |
 LL |     let _ = format!("{x}");
    |             ^^^^^^^^^^^^^^ help: consider using `.to_string()`: `x.to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:89:13
+  --> $DIR/format.rs:85:13
    |
 LL |     let _ = format!("{y}", y = x);
    |             ^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `x.to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:93:13
+  --> $DIR/format.rs:89:13
    |
 LL |     let _ = format!("{abc}");
    |             ^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `abc.to_string()`
 
 error: useless use of `format!`
-  --> $DIR/format.rs:95:13
+  --> $DIR/format.rs:91:13
    |
 LL |     let _ = format!("{xx}");
    |             ^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `xx.to_string()`
 
-error: aborting due to 19 previous errors
+error: aborting due to 15 previous errors
 
diff --git a/src/tools/clippy/tests/ui/format_args.fixed b/src/tools/clippy/tests/ui/format_args.fixed
index 69b5e1c722e0..e1c2d4d70be4 100644
--- a/src/tools/clippy/tests/ui/format_args.fixed
+++ b/src/tools/clippy/tests/ui/format_args.fixed
@@ -1,8 +1,6 @@
 // run-rustfix
 
-#![allow(unreachable_code)]
-#![allow(unused_macros)]
-#![allow(unused_variables)]
+#![allow(unused)]
 #![allow(clippy::assertions_on_constants)]
 #![allow(clippy::eq_op)]
 #![allow(clippy::print_literal)]
@@ -115,3 +113,50 @@ fn main() {
     // https://github.com/rust-lang/rust-clippy/issues/7903
     println!("{foo}{foo:?}", foo = "foo".to_string());
 }
+
+fn issue8643(vendor_id: usize, product_id: usize, name: &str) {
+    println!(
+        "{:<9}  {:<10}  {}",
+        format!("0x{:x}", vendor_id),
+        format!("0x{:x}", product_id),
+        name
+    );
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/8855
+mod issue_8855 {
+    #![allow(dead_code)]
+
+    struct A {}
+
+    impl std::fmt::Display for A {
+        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+            write!(f, "test")
+        }
+    }
+
+    fn main() {
+        let a = A {};
+        let b = A {};
+
+        let x = format!("{} {}", a, b);
+        dbg!(x);
+
+        let x = format!("{:>6} {:>6}", a, b.to_string());
+        dbg!(x);
+    }
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/9256
+mod issue_9256 {
+    #![allow(dead_code)]
+
+    fn print_substring(original: &str) {
+        assert!(original.len() > 10);
+        println!("{}", &original[..10]);
+    }
+
+    fn main() {
+        print_substring("Hello, world!");
+    }
+}
diff --git a/src/tools/clippy/tests/ui/format_args.rs b/src/tools/clippy/tests/ui/format_args.rs
index 3a434c5bf002..b9a4d66c28ad 100644
--- a/src/tools/clippy/tests/ui/format_args.rs
+++ b/src/tools/clippy/tests/ui/format_args.rs
@@ -1,8 +1,6 @@
 // run-rustfix
 
-#![allow(unreachable_code)]
-#![allow(unused_macros)]
-#![allow(unused_variables)]
+#![allow(unused)]
 #![allow(clippy::assertions_on_constants)]
 #![allow(clippy::eq_op)]
 #![allow(clippy::print_literal)]
@@ -115,3 +113,50 @@ fn main() {
     // https://github.com/rust-lang/rust-clippy/issues/7903
     println!("{foo}{foo:?}", foo = "foo".to_string());
 }
+
+fn issue8643(vendor_id: usize, product_id: usize, name: &str) {
+    println!(
+        "{:<9}  {:<10}  {}",
+        format!("0x{:x}", vendor_id),
+        format!("0x{:x}", product_id),
+        name
+    );
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/8855
+mod issue_8855 {
+    #![allow(dead_code)]
+
+    struct A {}
+
+    impl std::fmt::Display for A {
+        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+            write!(f, "test")
+        }
+    }
+
+    fn main() {
+        let a = A {};
+        let b = A {};
+
+        let x = format!("{} {}", a, b.to_string());
+        dbg!(x);
+
+        let x = format!("{:>6} {:>6}", a, b.to_string());
+        dbg!(x);
+    }
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/9256
+mod issue_9256 {
+    #![allow(dead_code)]
+
+    fn print_substring(original: &str) {
+        assert!(original.len() > 10);
+        println!("{}", original[..10].to_string());
+    }
+
+    fn main() {
+        print_substring("Hello, world!");
+    }
+}
diff --git a/src/tools/clippy/tests/ui/format_args.stderr b/src/tools/clippy/tests/ui/format_args.stderr
index c0cbca507958..aa6e3659b43b 100644
--- a/src/tools/clippy/tests/ui/format_args.stderr
+++ b/src/tools/clippy/tests/ui/format_args.stderr
@@ -1,5 +1,5 @@
 error: `to_string` applied to a type that implements `Display` in `format!` args
-  --> $DIR/format_args.rs:76:72
+  --> $DIR/format_args.rs:74:72
    |
 LL |     let _ = format!("error: something failed at {}", Location::caller().to_string());
    |                                                                        ^^^^^^^^^^^^ help: remove this
@@ -7,124 +7,136 @@ LL |     let _ = format!("error: something failed at {}", Location::caller().to_
    = note: `-D clippy::to-string-in-format-args` implied by `-D warnings`
 
 error: `to_string` applied to a type that implements `Display` in `write!` args
-  --> $DIR/format_args.rs:80:27
+  --> $DIR/format_args.rs:78:27
    |
 LL |         Location::caller().to_string()
    |                           ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `writeln!` args
-  --> $DIR/format_args.rs:85:27
+  --> $DIR/format_args.rs:83:27
    |
 LL |         Location::caller().to_string()
    |                           ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `print!` args
-  --> $DIR/format_args.rs:87:63
+  --> $DIR/format_args.rs:85:63
    |
 LL |     print!("error: something failed at {}", Location::caller().to_string());
    |                                                               ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:88:65
+  --> $DIR/format_args.rs:86:65
    |
 LL |     println!("error: something failed at {}", Location::caller().to_string());
    |                                                                 ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `eprint!` args
-  --> $DIR/format_args.rs:89:64
+  --> $DIR/format_args.rs:87:64
    |
 LL |     eprint!("error: something failed at {}", Location::caller().to_string());
    |                                                                ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `eprintln!` args
-  --> $DIR/format_args.rs:90:66
+  --> $DIR/format_args.rs:88:66
    |
 LL |     eprintln!("error: something failed at {}", Location::caller().to_string());
    |                                                                  ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `format_args!` args
-  --> $DIR/format_args.rs:91:77
+  --> $DIR/format_args.rs:89:77
    |
 LL |     let _ = format_args!("error: something failed at {}", Location::caller().to_string());
    |                                                                             ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `assert!` args
-  --> $DIR/format_args.rs:92:70
+  --> $DIR/format_args.rs:90:70
    |
 LL |     assert!(true, "error: something failed at {}", Location::caller().to_string());
    |                                                                      ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `assert_eq!` args
-  --> $DIR/format_args.rs:93:73
+  --> $DIR/format_args.rs:91:73
    |
 LL |     assert_eq!(0, 0, "error: something failed at {}", Location::caller().to_string());
    |                                                                         ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `assert_ne!` args
-  --> $DIR/format_args.rs:94:73
+  --> $DIR/format_args.rs:92:73
    |
 LL |     assert_ne!(0, 0, "error: something failed at {}", Location::caller().to_string());
    |                                                                         ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `panic!` args
-  --> $DIR/format_args.rs:95:63
+  --> $DIR/format_args.rs:93:63
    |
 LL |     panic!("error: something failed at {}", Location::caller().to_string());
    |                                                               ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:96:20
+  --> $DIR/format_args.rs:94:20
    |
 LL |     println!("{}", X(1).to_string());
    |                    ^^^^^^^^^^^^^^^^ help: use this: `*X(1)`
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:97:20
+  --> $DIR/format_args.rs:95:20
    |
 LL |     println!("{}", Y(&X(1)).to_string());
    |                    ^^^^^^^^^^^^^^^^^^^^ help: use this: `***Y(&X(1))`
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:98:24
+  --> $DIR/format_args.rs:96:24
    |
 LL |     println!("{}", Z(1).to_string());
    |                        ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:99:20
+  --> $DIR/format_args.rs:97:20
    |
 LL |     println!("{}", x.to_string());
    |                    ^^^^^^^^^^^^^ help: use this: `**x`
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:100:20
+  --> $DIR/format_args.rs:98:20
    |
 LL |     println!("{}", x_ref.to_string());
    |                    ^^^^^^^^^^^^^^^^^ help: use this: `***x_ref`
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:102:39
+  --> $DIR/format_args.rs:100:39
    |
 LL |     println!("{foo}{bar}", foo = "foo".to_string(), bar = "bar");
    |                                       ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:103:52
+  --> $DIR/format_args.rs:101:52
    |
 LL |     println!("{foo}{bar}", foo = "foo", bar = "bar".to_string());
    |                                                    ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:104:39
+  --> $DIR/format_args.rs:102:39
    |
 LL |     println!("{foo}{bar}", bar = "bar".to_string(), foo = "foo");
    |                                       ^^^^^^^^^^^^ help: remove this
 
 error: `to_string` applied to a type that implements `Display` in `println!` args
-  --> $DIR/format_args.rs:105:52
+  --> $DIR/format_args.rs:103:52
    |
 LL |     println!("{foo}{bar}", bar = "bar", foo = "foo".to_string());
    |                                                    ^^^^^^^^^^^^ help: remove this
 
-error: aborting due to 21 previous errors
+error: `to_string` applied to a type that implements `Display` in `format!` args
+  --> $DIR/format_args.rs:142:38
+   |
+LL |         let x = format!("{} {}", a, b.to_string());
+   |                                      ^^^^^^^^^^^^ help: remove this
+
+error: `to_string` applied to a type that implements `Display` in `println!` args
+  --> $DIR/format_args.rs:156:24
+   |
+LL |         println!("{}", original[..10].to_string());
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use this: `&original[..10]`
+
+error: aborting due to 23 previous errors
 
diff --git a/src/tools/clippy/tests/ui/identity_op.fixed b/src/tools/clippy/tests/ui/identity_op.fixed
index 5f9cebe212ab..fa564e23cd27 100644
--- a/src/tools/clippy/tests/ui/identity_op.fixed
+++ b/src/tools/clippy/tests/ui/identity_op.fixed
@@ -68,7 +68,7 @@ fn main() {
     &x;
     x;
 
-    let mut a = A("".into());
+    let mut a = A(String::new());
     let b = a << 0; // no error: non-integer
 
     1 * Meter; // no error: non-integer
diff --git a/src/tools/clippy/tests/ui/identity_op.rs b/src/tools/clippy/tests/ui/identity_op.rs
index ca799c9cfac0..3d06d2a73b62 100644
--- a/src/tools/clippy/tests/ui/identity_op.rs
+++ b/src/tools/clippy/tests/ui/identity_op.rs
@@ -68,7 +68,7 @@ fn main() {
     &x >> 0;
     x >> &0;
 
-    let mut a = A("".into());
+    let mut a = A(String::new());
     let b = a << 0; // no error: non-integer
 
     1 * Meter; // no error: non-integer
diff --git a/src/tools/clippy/tests/ui/if_let_mutex.rs b/src/tools/clippy/tests/ui/if_let_mutex.rs
index 6cbfafbb38b9..321feb0224ed 100644
--- a/src/tools/clippy/tests/ui/if_let_mutex.rs
+++ b/src/tools/clippy/tests/ui/if_let_mutex.rs
@@ -39,4 +39,12 @@ fn if_let_different_mutex() {
     };
 }
 
+fn mutex_ref(mutex: &Mutex<i32>) {
+    if let Ok(i) = mutex.lock() {
+        do_stuff(i);
+    } else {
+        let _x = mutex.lock();
+    };
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/if_let_mutex.stderr b/src/tools/clippy/tests/ui/if_let_mutex.stderr
index e9c4d9163328..8a4d5dbac592 100644
--- a/src/tools/clippy/tests/ui/if_let_mutex.stderr
+++ b/src/tools/clippy/tests/ui/if_let_mutex.stderr
@@ -1,10 +1,14 @@
 error: calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a deadlock
   --> $DIR/if_let_mutex.rs:10:5
    |
-LL | /     if let Err(locked) = m.lock() {
+LL |       if let Err(locked) = m.lock() {
+   |       ^                    - this Mutex will remain locked for the entire `if let`-block...
+   |  _____|
+   | |
 LL | |         do_stuff(locked);
 LL | |     } else {
 LL | |         let lock = m.lock().unwrap();
+   | |                    - ... and is tried to lock again here, which will always deadlock.
 LL | |         do_stuff(lock);
 LL | |     };
    | |_____^
@@ -15,15 +19,35 @@ LL | |     };
 error: calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a deadlock
   --> $DIR/if_let_mutex.rs:22:5
    |
-LL | /     if let Some(locked) = m.lock().unwrap().deref() {
+LL |       if let Some(locked) = m.lock().unwrap().deref() {
+   |       ^                     - this Mutex will remain locked for the entire `if let`-block...
+   |  _____|
+   | |
 LL | |         do_stuff(locked);
 LL | |     } else {
 LL | |         let lock = m.lock().unwrap();
+   | |                    - ... and is tried to lock again here, which will always deadlock.
 LL | |         do_stuff(lock);
 LL | |     };
    | |_____^
    |
    = help: move the lock call outside of the `if let ...` expression
 
-error: aborting due to 2 previous errors
+error: calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a deadlock
+  --> $DIR/if_let_mutex.rs:43:5
+   |
+LL |       if let Ok(i) = mutex.lock() {
+   |       ^              ----- this Mutex will remain locked for the entire `if let`-block...
+   |  _____|
+   | |
+LL | |         do_stuff(i);
+LL | |     } else {
+LL | |         let _x = mutex.lock();
+   | |                  ----- ... and is tried to lock again here, which will always deadlock.
+LL | |     };
+   | |_____^
+   |
+   = help: move the lock call outside of the `if let ...` expression
+
+error: aborting due to 3 previous errors
 
diff --git a/src/tools/clippy/tests/ui/if_then_some_else_none.stderr b/src/tools/clippy/tests/ui/if_then_some_else_none.stderr
index 8cb22d569f4c..c22ace30d2dc 100644
--- a/src/tools/clippy/tests/ui/if_then_some_else_none.stderr
+++ b/src/tools/clippy/tests/ui/if_then_some_else_none.stderr
@@ -27,21 +27,21 @@ LL | |     };
    |
    = help: consider using `bool::then` like: `matches!(true, true).then(|| { /* snippet */ matches!(true, false) })`
 
-error: this could be simplified with `bool::then`
+error: this could be simplified with `bool::then_some`
   --> $DIR/if_then_some_else_none.rs:23:28
    |
 LL |     let _ = x.and_then(|o| if o < 32 { Some(o) } else { None });
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider using `bool::then` like: `(o < 32).then(|| o)`
+   = help: consider using `bool::then_some` like: `(o < 32).then_some(o)`
 
-error: this could be simplified with `bool::then`
+error: this could be simplified with `bool::then_some`
   --> $DIR/if_then_some_else_none.rs:27:13
    |
 LL |     let _ = if !x { Some(0) } else { None };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider using `bool::then` like: `(!x).then(|| 0)`
+   = help: consider using `bool::then_some` like: `(!x).then_some(0)`
 
 error: this could be simplified with `bool::then`
   --> $DIR/if_then_some_else_none.rs:82:13
diff --git a/src/tools/clippy/tests/ui/inefficient_to_string.stderr b/src/tools/clippy/tests/ui/inefficient_to_string.stderr
index 4be46161e8b7..1c0490ffa44c 100644
--- a/src/tools/clippy/tests/ui/inefficient_to_string.stderr
+++ b/src/tools/clippy/tests/ui/inefficient_to_string.stderr
@@ -35,21 +35,21 @@ LL |     let _: String = rrrstring.to_string();
    |
    = help: `&&std::string::String` implements `ToString` through a slower blanket impl, but `std::string::String` has a fast specialization of `ToString`
 
-error: calling `to_string` on `&&std::borrow::Cow<str>`
+error: calling `to_string` on `&&std::borrow::Cow<'_, str>`
   --> $DIR/inefficient_to_string.rs:29:21
    |
 LL |     let _: String = rrcow.to_string();
    |                     ^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(*rrcow).to_string()`
    |
-   = help: `&std::borrow::Cow<str>` implements `ToString` through a slower blanket impl, but `std::borrow::Cow<str>` has a fast specialization of `ToString`
+   = help: `&std::borrow::Cow<'_, str>` implements `ToString` through a slower blanket impl, but `std::borrow::Cow<'_, str>` has a fast specialization of `ToString`
 
-error: calling `to_string` on `&&&std::borrow::Cow<str>`
+error: calling `to_string` on `&&&std::borrow::Cow<'_, str>`
   --> $DIR/inefficient_to_string.rs:30:21
    |
 LL |     let _: String = rrrcow.to_string();
    |                     ^^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(**rrrcow).to_string()`
    |
-   = help: `&&std::borrow::Cow<str>` implements `ToString` through a slower blanket impl, but `std::borrow::Cow<str>` has a fast specialization of `ToString`
+   = help: `&&std::borrow::Cow<'_, str>` implements `ToString` through a slower blanket impl, but `std::borrow::Cow<'_, str>` has a fast specialization of `ToString`
 
 error: aborting due to 6 previous errors
 
diff --git a/src/tools/clippy/tests/ui/iter_kv_map.fixed b/src/tools/clippy/tests/ui/iter_kv_map.fixed
new file mode 100644
index 000000000000..83fee04080fa
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_kv_map.fixed
@@ -0,0 +1,64 @@
+// run-rustfix
+
+#![warn(clippy::iter_kv_map)]
+#![allow(clippy::redundant_clone)]
+#![allow(clippy::suspicious_map)]
+#![allow(clippy::map_identity)]
+
+use std::collections::{BTreeMap, HashMap};
+
+fn main() {
+    let get_key = |(key, _val)| key;
+
+    let map: HashMap<u32, u32> = HashMap::new();
+
+    let _ = map.keys().collect::<Vec<_>>();
+    let _ = map.values().collect::<Vec<_>>();
+    let _ = map.values().map(|v| v + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_keys().collect::<Vec<_>>();
+    let _ = map.clone().into_keys().map(|key| key + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_values().collect::<Vec<_>>();
+    let _ = map.clone().into_values().map(|val| val + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().values().collect::<Vec<_>>();
+    let _ = map.keys().filter(|x| *x % 2 == 0).count();
+
+    // Don't lint
+    let _ = map.iter().filter(|(_, val)| *val % 2 == 0).map(|(key, _)| key).count();
+    let _ = map.iter().map(get_key).collect::<Vec<_>>();
+
+    // Linting the following could be an improvement to the lint
+    // map.iter().filter_map(|(_, val)| (val % 2 == 0).then(val * 17)).count();
+
+    // Lint
+    let _ = map.keys().map(|key| key * 9).count();
+    let _ = map.values().map(|value| value * 17).count();
+
+    let map: BTreeMap<u32, u32> = BTreeMap::new();
+
+    let _ = map.keys().collect::<Vec<_>>();
+    let _ = map.values().collect::<Vec<_>>();
+    let _ = map.values().map(|v| v + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_keys().collect::<Vec<_>>();
+    let _ = map.clone().into_keys().map(|key| key + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_values().collect::<Vec<_>>();
+    let _ = map.clone().into_values().map(|val| val + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().values().collect::<Vec<_>>();
+    let _ = map.keys().filter(|x| *x % 2 == 0).count();
+
+    // Don't lint
+    let _ = map.iter().filter(|(_, val)| *val % 2 == 0).map(|(key, _)| key).count();
+    let _ = map.iter().map(get_key).collect::<Vec<_>>();
+
+    // Linting the following could be an improvement to the lint
+    // map.iter().filter_map(|(_, val)| (val % 2 == 0).then(val * 17)).count();
+
+    // Lint
+    let _ = map.keys().map(|key| key * 9).count();
+    let _ = map.values().map(|value| value * 17).count();
+}
diff --git a/src/tools/clippy/tests/ui/iter_kv_map.rs b/src/tools/clippy/tests/ui/iter_kv_map.rs
new file mode 100644
index 000000000000..7a1f1fb0198c
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_kv_map.rs
@@ -0,0 +1,64 @@
+// run-rustfix
+
+#![warn(clippy::iter_kv_map)]
+#![allow(clippy::redundant_clone)]
+#![allow(clippy::suspicious_map)]
+#![allow(clippy::map_identity)]
+
+use std::collections::{BTreeMap, HashMap};
+
+fn main() {
+    let get_key = |(key, _val)| key;
+
+    let map: HashMap<u32, u32> = HashMap::new();
+
+    let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+    let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+    let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().iter().map(|(_, val)| val).collect::<Vec<_>>();
+    let _ = map.iter().map(|(key, _)| key).filter(|x| *x % 2 == 0).count();
+
+    // Don't lint
+    let _ = map.iter().filter(|(_, val)| *val % 2 == 0).map(|(key, _)| key).count();
+    let _ = map.iter().map(get_key).collect::<Vec<_>>();
+
+    // Linting the following could be an improvement to the lint
+    // map.iter().filter_map(|(_, val)| (val % 2 == 0).then(val * 17)).count();
+
+    // Lint
+    let _ = map.iter().map(|(key, _value)| key * 9).count();
+    let _ = map.iter().map(|(_key, value)| value * 17).count();
+
+    let map: BTreeMap<u32, u32> = BTreeMap::new();
+
+    let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+    let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+    let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+    let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+
+    let _ = map.clone().iter().map(|(_, val)| val).collect::<Vec<_>>();
+    let _ = map.iter().map(|(key, _)| key).filter(|x| *x % 2 == 0).count();
+
+    // Don't lint
+    let _ = map.iter().filter(|(_, val)| *val % 2 == 0).map(|(key, _)| key).count();
+    let _ = map.iter().map(get_key).collect::<Vec<_>>();
+
+    // Linting the following could be an improvement to the lint
+    // map.iter().filter_map(|(_, val)| (val % 2 == 0).then(val * 17)).count();
+
+    // Lint
+    let _ = map.iter().map(|(key, _value)| key * 9).count();
+    let _ = map.iter().map(|(_key, value)| value * 17).count();
+}
diff --git a/src/tools/clippy/tests/ui/iter_kv_map.stderr b/src/tools/clippy/tests/ui/iter_kv_map.stderr
new file mode 100644
index 000000000000..9b9b04c97d81
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_kv_map.stderr
@@ -0,0 +1,136 @@
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:15:13
+   |
+LL |     let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys()`
+   |
+   = note: `-D clippy::iter-kv-map` implied by `-D warnings`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:16:13
+   |
+LL |     let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:17:13
+   |
+LL |     let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values().map(|v| v + 2)`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:19:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_keys()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:20:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_keys().map(|key| key + 2)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:22:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:23:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values().map(|val| val + 2)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:25:13
+   |
+LL |     let _ = map.clone().iter().map(|(_, val)| val).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().values()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:26:13
+   |
+LL |     let _ = map.iter().map(|(key, _)| key).filter(|x| *x % 2 == 0).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:36:13
+   |
+LL |     let _ = map.iter().map(|(key, _value)| key * 9).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys().map(|key| key * 9)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:37:13
+   |
+LL |     let _ = map.iter().map(|(_key, value)| value * 17).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values().map(|value| value * 17)`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:41:13
+   |
+LL |     let _ = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:42:13
+   |
+LL |     let _ = map.iter().map(|(_, value)| value).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:43:13
+   |
+LL |     let _ = map.iter().map(|(_, v)| v + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values().map(|v| v + 2)`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:45:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(key, _)| key).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_keys()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:46:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(key, _)| key + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_keys().map(|key| key + 2)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:48:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(_, val)| val).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values()`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:49:13
+   |
+LL |     let _ = map.clone().into_iter().map(|(_, val)| val + 2).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().into_values().map(|val| val + 2)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:51:13
+   |
+LL |     let _ = map.clone().iter().map(|(_, val)| val).collect::<Vec<_>>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.clone().values()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:52:13
+   |
+LL |     let _ = map.iter().map(|(key, _)| key).filter(|x| *x % 2 == 0).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys()`
+
+error: iterating on a map's keys
+  --> $DIR/iter_kv_map.rs:62:13
+   |
+LL |     let _ = map.iter().map(|(key, _value)| key * 9).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.keys().map(|key| key * 9)`
+
+error: iterating on a map's values
+  --> $DIR/iter_kv_map.rs:63:13
+   |
+LL |     let _ = map.iter().map(|(_key, value)| value * 17).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `map.values().map(|value| value * 17)`
+
+error: aborting due to 22 previous errors
+
diff --git a/src/tools/clippy/tests/ui/iter_on_empty_collections.fixed b/src/tools/clippy/tests/ui/iter_on_empty_collections.fixed
new file mode 100644
index 000000000000..bd9b07aefbfb
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_empty_collections.fixed
@@ -0,0 +1,63 @@
+// run-rustfix
+#![warn(clippy::iter_on_empty_collections)]
+#![allow(clippy::iter_next_slice, clippy::redundant_clone)]
+
+fn array() {
+    assert_eq!(std::iter::empty().next(), Option::<i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&mut i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&mut i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&i32>::None);
+
+    // Don't trigger on non-iter methods
+    let _: Option<String> = None.clone();
+    let _: [String; 0] = [].clone();
+
+    // Don't trigger on match or if branches
+    let _ = match 123 {
+        123 => [].iter(),
+        _ => ["test"].iter(),
+    };
+
+    let _ = if false { ["test"].iter() } else { [].iter() };
+}
+
+macro_rules! in_macros {
+    () => {
+        assert_eq!([].into_iter().next(), Option::<i32>::None);
+        assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
+        assert_eq!([].iter().next(), Option::<&i32>::None);
+        assert_eq!(None.into_iter().next(), Option::<i32>::None);
+        assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
+        assert_eq!(None.iter().next(), Option::<&i32>::None);
+    };
+}
+
+// Don't trigger on a `None` that isn't std's option
+mod custom_option {
+    #[allow(unused)]
+    enum CustomOption {
+        Some(i32),
+        None,
+    }
+
+    impl CustomOption {
+        fn iter(&self) {}
+        fn iter_mut(&mut self) {}
+        fn into_iter(self) {}
+    }
+    use CustomOption::*;
+
+    pub fn custom_option() {
+        None.iter();
+        None.iter_mut();
+        None.into_iter();
+    }
+}
+
+fn main() {
+    array();
+    custom_option::custom_option();
+    in_macros!();
+}
diff --git a/src/tools/clippy/tests/ui/iter_on_empty_collections.rs b/src/tools/clippy/tests/ui/iter_on_empty_collections.rs
new file mode 100644
index 000000000000..e15ba94bd465
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_empty_collections.rs
@@ -0,0 +1,63 @@
+// run-rustfix
+#![warn(clippy::iter_on_empty_collections)]
+#![allow(clippy::iter_next_slice, clippy::redundant_clone)]
+
+fn array() {
+    assert_eq!([].into_iter().next(), Option::<i32>::None);
+    assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
+    assert_eq!([].iter().next(), Option::<&i32>::None);
+    assert_eq!(None.into_iter().next(), Option::<i32>::None);
+    assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
+    assert_eq!(None.iter().next(), Option::<&i32>::None);
+
+    // Don't trigger on non-iter methods
+    let _: Option<String> = None.clone();
+    let _: [String; 0] = [].clone();
+
+    // Don't trigger on match or if branches
+    let _ = match 123 {
+        123 => [].iter(),
+        _ => ["test"].iter(),
+    };
+
+    let _ = if false { ["test"].iter() } else { [].iter() };
+}
+
+macro_rules! in_macros {
+    () => {
+        assert_eq!([].into_iter().next(), Option::<i32>::None);
+        assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
+        assert_eq!([].iter().next(), Option::<&i32>::None);
+        assert_eq!(None.into_iter().next(), Option::<i32>::None);
+        assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
+        assert_eq!(None.iter().next(), Option::<&i32>::None);
+    };
+}
+
+// Don't trigger on a `None` that isn't std's option
+mod custom_option {
+    #[allow(unused)]
+    enum CustomOption {
+        Some(i32),
+        None,
+    }
+
+    impl CustomOption {
+        fn iter(&self) {}
+        fn iter_mut(&mut self) {}
+        fn into_iter(self) {}
+    }
+    use CustomOption::*;
+
+    pub fn custom_option() {
+        None.iter();
+        None.iter_mut();
+        None.into_iter();
+    }
+}
+
+fn main() {
+    array();
+    custom_option::custom_option();
+    in_macros!();
+}
diff --git a/src/tools/clippy/tests/ui/iter_on_empty_collections.stderr b/src/tools/clippy/tests/ui/iter_on_empty_collections.stderr
new file mode 100644
index 000000000000..cbd611769569
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_empty_collections.stderr
@@ -0,0 +1,40 @@
+error: `into_iter` call on an empty collection
+  --> $DIR/iter_on_empty_collections.rs:6:16
+   |
+LL |     assert_eq!([].into_iter().next(), Option::<i32>::None);
+   |                ^^^^^^^^^^^^^^ help: try: `std::iter::empty()`
+   |
+   = note: `-D clippy::iter-on-empty-collections` implied by `-D warnings`
+
+error: `iter_mut` call on an empty collection
+  --> $DIR/iter_on_empty_collections.rs:7:16
+   |
+LL |     assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
+   |                ^^^^^^^^^^^^^ help: try: `std::iter::empty()`
+
+error: `iter` call on an empty collection
+  --> $DIR/iter_on_empty_collections.rs:8:16
+   |
+LL |     assert_eq!([].iter().next(), Option::<&i32>::None);
+   |                ^^^^^^^^^ help: try: `std::iter::empty()`
+
+error: `into_iter` call on an empty collection
+  --> $DIR/iter_on_empty_collections.rs:9:16
+   |
+LL |     assert_eq!(None.into_iter().next(), Option::<i32>::None);
+   |                ^^^^^^^^^^^^^^^^ help: try: `std::iter::empty()`
+
+error: `iter_mut` call on an empty collection
+  --> $DIR/iter_on_empty_collections.rs:10:16
+   |
+LL |     assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
+   |                ^^^^^^^^^^^^^^^ help: try: `std::iter::empty()`
+
+error: `iter` call on an empty collection
+  --> $DIR/iter_on_empty_collections.rs:11:16
+   |
+LL |     assert_eq!(None.iter().next(), Option::<&i32>::None);
+   |                ^^^^^^^^^^^ help: try: `std::iter::empty()`
+
+error: aborting due to 6 previous errors
+
diff --git a/src/tools/clippy/tests/ui/iter_on_single_items.fixed b/src/tools/clippy/tests/ui/iter_on_single_items.fixed
new file mode 100644
index 000000000000..1fa4b03641bc
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_single_items.fixed
@@ -0,0 +1,63 @@
+// run-rustfix
+#![warn(clippy::iter_on_single_items)]
+#![allow(clippy::iter_next_slice, clippy::redundant_clone)]
+
+fn array() {
+    assert_eq!(std::iter::once(123).next(), Some(123));
+    assert_eq!(std::iter::once(&mut 123).next(), Some(&mut 123));
+    assert_eq!(std::iter::once(&123).next(), Some(&123));
+    assert_eq!(std::iter::once(123).next(), Some(123));
+    assert_eq!(std::iter::once(&mut 123).next(), Some(&mut 123));
+    assert_eq!(std::iter::once(&123).next(), Some(&123));
+
+    // Don't trigger on non-iter methods
+    let _: Option<String> = Some("test".to_string()).clone();
+    let _: [String; 1] = ["test".to_string()].clone();
+
+    // Don't trigger on match or if branches
+    let _ = match 123 {
+        123 => [].iter(),
+        _ => ["test"].iter(),
+    };
+
+    let _ = if false { ["test"].iter() } else { [].iter() };
+}
+
+macro_rules! in_macros {
+    () => {
+        assert_eq!([123].into_iter().next(), Some(123));
+        assert_eq!([123].iter_mut().next(), Some(&mut 123));
+        assert_eq!([123].iter().next(), Some(&123));
+        assert_eq!(Some(123).into_iter().next(), Some(123));
+        assert_eq!(Some(123).iter_mut().next(), Some(&mut 123));
+        assert_eq!(Some(123).iter().next(), Some(&123));
+    };
+}
+
+// Don't trigger on a `Some` that isn't std's option
+mod custom_option {
+    #[allow(unused)]
+    enum CustomOption {
+        Some(i32),
+        None,
+    }
+
+    impl CustomOption {
+        fn iter(&self) {}
+        fn iter_mut(&mut self) {}
+        fn into_iter(self) {}
+    }
+    use CustomOption::*;
+
+    pub fn custom_option() {
+        Some(3).iter();
+        Some(3).iter_mut();
+        Some(3).into_iter();
+    }
+}
+
+fn main() {
+    array();
+    custom_option::custom_option();
+    in_macros!();
+}
diff --git a/src/tools/clippy/tests/ui/iter_on_single_items.rs b/src/tools/clippy/tests/ui/iter_on_single_items.rs
new file mode 100644
index 000000000000..ea96d8066c56
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_single_items.rs
@@ -0,0 +1,63 @@
+// run-rustfix
+#![warn(clippy::iter_on_single_items)]
+#![allow(clippy::iter_next_slice, clippy::redundant_clone)]
+
+fn array() {
+    assert_eq!([123].into_iter().next(), Some(123));
+    assert_eq!([123].iter_mut().next(), Some(&mut 123));
+    assert_eq!([123].iter().next(), Some(&123));
+    assert_eq!(Some(123).into_iter().next(), Some(123));
+    assert_eq!(Some(123).iter_mut().next(), Some(&mut 123));
+    assert_eq!(Some(123).iter().next(), Some(&123));
+
+    // Don't trigger on non-iter methods
+    let _: Option<String> = Some("test".to_string()).clone();
+    let _: [String; 1] = ["test".to_string()].clone();
+
+    // Don't trigger on match or if branches
+    let _ = match 123 {
+        123 => [].iter(),
+        _ => ["test"].iter(),
+    };
+
+    let _ = if false { ["test"].iter() } else { [].iter() };
+}
+
+macro_rules! in_macros {
+    () => {
+        assert_eq!([123].into_iter().next(), Some(123));
+        assert_eq!([123].iter_mut().next(), Some(&mut 123));
+        assert_eq!([123].iter().next(), Some(&123));
+        assert_eq!(Some(123).into_iter().next(), Some(123));
+        assert_eq!(Some(123).iter_mut().next(), Some(&mut 123));
+        assert_eq!(Some(123).iter().next(), Some(&123));
+    };
+}
+
+// Don't trigger on a `Some` that isn't std's option
+mod custom_option {
+    #[allow(unused)]
+    enum CustomOption {
+        Some(i32),
+        None,
+    }
+
+    impl CustomOption {
+        fn iter(&self) {}
+        fn iter_mut(&mut self) {}
+        fn into_iter(self) {}
+    }
+    use CustomOption::*;
+
+    pub fn custom_option() {
+        Some(3).iter();
+        Some(3).iter_mut();
+        Some(3).into_iter();
+    }
+}
+
+fn main() {
+    array();
+    custom_option::custom_option();
+    in_macros!();
+}
diff --git a/src/tools/clippy/tests/ui/iter_on_single_items.stderr b/src/tools/clippy/tests/ui/iter_on_single_items.stderr
new file mode 100644
index 000000000000..d6c547116363
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_single_items.stderr
@@ -0,0 +1,40 @@
+error: `into_iter` call on a collection with only one item
+  --> $DIR/iter_on_single_items.rs:6:16
+   |
+LL |     assert_eq!([123].into_iter().next(), Some(123));
+   |                ^^^^^^^^^^^^^^^^^ help: try: `std::iter::once(123)`
+   |
+   = note: `-D clippy::iter-on-single-items` implied by `-D warnings`
+
+error: `iter_mut` call on a collection with only one item
+  --> $DIR/iter_on_single_items.rs:7:16
+   |
+LL |     assert_eq!([123].iter_mut().next(), Some(&mut 123));
+   |                ^^^^^^^^^^^^^^^^ help: try: `std::iter::once(&mut 123)`
+
+error: `iter` call on a collection with only one item
+  --> $DIR/iter_on_single_items.rs:8:16
+   |
+LL |     assert_eq!([123].iter().next(), Some(&123));
+   |                ^^^^^^^^^^^^ help: try: `std::iter::once(&123)`
+
+error: `into_iter` call on a collection with only one item
+  --> $DIR/iter_on_single_items.rs:9:16
+   |
+LL |     assert_eq!(Some(123).into_iter().next(), Some(123));
+   |                ^^^^^^^^^^^^^^^^^^^^^ help: try: `std::iter::once(123)`
+
+error: `iter_mut` call on a collection with only one item
+  --> $DIR/iter_on_single_items.rs:10:16
+   |
+LL |     assert_eq!(Some(123).iter_mut().next(), Some(&mut 123));
+   |                ^^^^^^^^^^^^^^^^^^^^ help: try: `std::iter::once(&mut 123)`
+
+error: `iter` call on a collection with only one item
+  --> $DIR/iter_on_single_items.rs:11:16
+   |
+LL |     assert_eq!(Some(123).iter().next(), Some(&123));
+   |                ^^^^^^^^^^^^^^^^ help: try: `std::iter::once(&123)`
+
+error: aborting due to 6 previous errors
+
diff --git a/src/tools/clippy/tests/ui/large_enum_variant.rs b/src/tools/clippy/tests/ui/large_enum_variant.rs
index 23152a13322e..3b96f09d7b1d 100644
--- a/src/tools/clippy/tests/ui/large_enum_variant.rs
+++ b/src/tools/clippy/tests/ui/large_enum_variant.rs
@@ -101,12 +101,12 @@ struct Struct2 {
 #[derive(Copy, Clone)]
 enum CopyableLargeEnum {
     A(bool),
-    B([u128; 4000]),
+    B([u64; 8000]),
 }
 
 enum ManuallyCopyLargeEnum {
     A(bool),
-    B([u128; 4000]),
+    B([u64; 8000]),
 }
 
 impl Clone for ManuallyCopyLargeEnum {
@@ -130,6 +130,30 @@ impl<T: Copy> Clone for SomeGenericPossiblyCopyEnum<T> {
 
 impl<T: Copy> Copy for SomeGenericPossiblyCopyEnum<T> {}
 
+enum LargeEnumWithGenerics<T> {
+    Small,
+    Large((T, [u8; 512])),
+}
+
+struct Foo<T> {
+    foo: T,
+}
+
+enum WithGenerics {
+    Large([Foo<u64>; 64]),
+    Small(u8),
+}
+
+enum PossiblyLargeEnumWithConst<const U: usize> {
+    SmallBuffer([u8; 4]),
+    MightyBuffer([u16; U]),
+}
+
+enum LargeEnumOfConst {
+    Ok,
+    Error(PossiblyLargeEnumWithConst<256>),
+}
+
 fn main() {
     large_enum_variant!();
 }
diff --git a/src/tools/clippy/tests/ui/large_enum_variant.stderr b/src/tools/clippy/tests/ui/large_enum_variant.stderr
index 0248327262da..709972b4a6e4 100644
--- a/src/tools/clippy/tests/ui/large_enum_variant.stderr
+++ b/src/tools/clippy/tests/ui/large_enum_variant.stderr
@@ -1,143 +1,177 @@
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:12:5
+  --> $DIR/large_enum_variant.rs:10:1
    |
-LL |     B([i32; 8000]),
-   |     ^^^^^^^^^^^^^^ this variant is 32000 bytes
+LL | / enum LargeEnum {
+LL | |     A(i32),
+   | |     ------ the second-largest variant contains at least 4 bytes
+LL | |     B([i32; 8000]),
+   | |     -------------- the largest variant contains at least 32000 bytes
+LL | | }
+   | |_^ the entire enum is at least 32004 bytes
    |
    = note: `-D clippy::large-enum-variant` implied by `-D warnings`
-note: and the second-largest variant is 4 bytes:
-  --> $DIR/large_enum_variant.rs:11:5
-   |
-LL |     A(i32),
-   |     ^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     B(Box<[i32; 8000]>),
    |       ~~~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:36:5
+  --> $DIR/large_enum_variant.rs:34:1
    |
-LL |     ContainingLargeEnum(LargeEnum),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this variant is 32004 bytes
+LL | / enum LargeEnum2 {
+LL | |     VariantOk(i32, u32),
+   | |     ------------------- the second-largest variant contains at least 8 bytes
+LL | |     ContainingLargeEnum(LargeEnum),
+   | |     ------------------------------ the largest variant contains at least 32004 bytes
+LL | | }
+   | |_^ the entire enum is at least 32004 bytes
    |
-note: and the second-largest variant is 8 bytes:
-  --> $DIR/large_enum_variant.rs:35:5
-   |
-LL |     VariantOk(i32, u32),
-   |     ^^^^^^^^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     ContainingLargeEnum(Box<LargeEnum>),
    |                         ~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:40:5
+  --> $DIR/large_enum_variant.rs:39:1
    |
-LL |     ContainingMoreThanOneField(i32, [i32; 8000], [i32; 9500]),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this variant is 70004 bytes
+LL | / enum LargeEnum3 {
+LL | |     ContainingMoreThanOneField(i32, [i32; 8000], [i32; 9500]),
+   | |     --------------------------------------------------------- the largest variant contains at least 70004 bytes
+LL | |     VoidVariant,
+LL | |     StructLikeLittle { x: i32, y: i32 },
+   | |     ----------------------------------- the second-largest variant contains at least 8 bytes
+LL | | }
+   | |_^ the entire enum is at least 70008 bytes
    |
-note: and the second-largest variant is 8 bytes:
-  --> $DIR/large_enum_variant.rs:42:5
-   |
-LL |     StructLikeLittle { x: i32, y: i32 },
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     ContainingMoreThanOneField(i32, Box<[i32; 8000]>, Box<[i32; 9500]>),
    |                                     ~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:47:5
+  --> $DIR/large_enum_variant.rs:45:1
    |
-LL |     StructLikeLarge { x: [i32; 8000], y: i32 },
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this variant is 32004 bytes
+LL | / enum LargeEnum4 {
+LL | |     VariantOk(i32, u32),
+   | |     ------------------- the second-largest variant contains at least 8 bytes
+LL | |     StructLikeLarge { x: [i32; 8000], y: i32 },
+   | |     ------------------------------------------ the largest variant contains at least 32004 bytes
+LL | | }
+   | |_^ the entire enum is at least 32008 bytes
    |
-note: and the second-largest variant is 8 bytes:
-  --> $DIR/large_enum_variant.rs:46:5
-   |
-LL |     VariantOk(i32, u32),
-   |     ^^^^^^^^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     StructLikeLarge { x: Box<[i32; 8000]>, y: i32 },
    |                          ~~~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:52:5
+  --> $DIR/large_enum_variant.rs:50:1
    |
-LL |     StructLikeLarge2 { x: [i32; 8000] },
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this variant is 32000 bytes
+LL | / enum LargeEnum5 {
+LL | |     VariantOk(i32, u32),
+   | |     ------------------- the second-largest variant contains at least 8 bytes
+LL | |     StructLikeLarge2 { x: [i32; 8000] },
+   | |     ----------------------------------- the largest variant contains at least 32000 bytes
+LL | | }
+   | |_^ the entire enum is at least 32004 bytes
    |
-note: and the second-largest variant is 8 bytes:
-  --> $DIR/large_enum_variant.rs:51:5
-   |
-LL |     VariantOk(i32, u32),
-   |     ^^^^^^^^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     StructLikeLarge2 { x: Box<[i32; 8000]> },
    |                           ~~~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:68:5
+  --> $DIR/large_enum_variant.rs:66:1
    |
-LL |     B([u8; 1255]),
-   |     ^^^^^^^^^^^^^ this variant is 1255 bytes
+LL | / enum LargeEnum7 {
+LL | |     A,
+LL | |     B([u8; 1255]),
+   | |     ------------- the largest variant contains at least 1255 bytes
+LL | |     C([u8; 200]),
+   | |     ------------ the second-largest variant contains at least 200 bytes
+LL | | }
+   | |_^ the entire enum is at least 1256 bytes
    |
-note: and the second-largest variant is 200 bytes:
-  --> $DIR/large_enum_variant.rs:69:5
-   |
-LL |     C([u8; 200]),
-   |     ^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     B(Box<[u8; 1255]>),
    |       ~~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:74:5
+  --> $DIR/large_enum_variant.rs:72:1
    |
-LL |     ContainingMoreThanOneField([i32; 8000], [i32; 2], [i32; 9500], [i32; 30]),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this variant is 70128 bytes
+LL | / enum LargeEnum8 {
+LL | |     VariantOk(i32, u32),
+   | |     ------------------- the second-largest variant contains at least 8 bytes
+LL | |     ContainingMoreThanOneField([i32; 8000], [i32; 2], [i32; 9500], [i32; 30]),
+   | |     ------------------------------------------------------------------------- the largest variant contains at least 70128 bytes
+LL | | }
+   | |_^ the entire enum is at least 70132 bytes
    |
-note: and the second-largest variant is 8 bytes:
-  --> $DIR/large_enum_variant.rs:73:5
-   |
-LL |     VariantOk(i32, u32),
-   |     ^^^^^^^^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     ContainingMoreThanOneField(Box<[i32; 8000]>, [i32; 2], Box<[i32; 9500]>, [i32; 30]),
    |                                ~~~~~~~~~~~~~~~~            ~~~~~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:79:5
+  --> $DIR/large_enum_variant.rs:77:1
    |
-LL |     B(Struct2),
-   |     ^^^^^^^^^^ this variant is 32000 bytes
+LL | / enum LargeEnum9 {
+LL | |     A(Struct<()>),
+   | |     ------------- the second-largest variant contains at least 4 bytes
+LL | |     B(Struct2),
+   | |     ---------- the largest variant contains at least 32000 bytes
+LL | | }
+   | |_^ the entire enum is at least 32004 bytes
    |
-note: and the second-largest variant is 4 bytes:
-  --> $DIR/large_enum_variant.rs:78:5
-   |
-LL |     A(Struct<()>),
-   |     ^^^^^^^^^^^^^
 help: consider boxing the large fields to reduce the total size of the enum
    |
 LL |     B(Box<Struct2>),
    |       ~~~~~~~~~~~~
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:104:5
+  --> $DIR/large_enum_variant.rs:82:1
    |
-LL |     B([u128; 4000]),
-   |     ^^^^^^^^^^^^^^^ this variant is 64000 bytes
+LL | / enum LargeEnumOk2<T> {
+LL | |     A(T),
+   | |     ---- the second-largest variant contains at least 0 bytes
+LL | |     B(Struct2),
+   | |     ---------- the largest variant contains at least 32000 bytes
+LL | | }
+   | |_^ the entire enum is at least 32000 bytes
    |
-note: and the second-largest variant is 1 bytes:
-  --> $DIR/large_enum_variant.rs:103:5
+help: consider boxing the large fields to reduce the total size of the enum
+   |
+LL |     B(Box<Struct2>),
+   |       ~~~~~~~~~~~~
+
+error: large size difference between variants
+  --> $DIR/large_enum_variant.rs:87:1
+   |
+LL | / enum LargeEnumOk3<T> {
+LL | |     A(Struct<T>),
+   | |     ------------ the second-largest variant contains at least 4 bytes
+LL | |     B(Struct2),
+   | |     ---------- the largest variant contains at least 32000 bytes
+LL | | }
+   | |_^ the entire enum is at least 32000 bytes
+   |
+help: consider boxing the large fields to reduce the total size of the enum
+   |
+LL |     B(Box<Struct2>),
+   |       ~~~~~~~~~~~~
+
+error: large size difference between variants
+  --> $DIR/large_enum_variant.rs:102:1
+   |
+LL | / enum CopyableLargeEnum {
+LL | |     A(bool),
+   | |     ------- the second-largest variant contains at least 1 bytes
+LL | |     B([u64; 8000]),
+   | |     -------------- the largest variant contains at least 64000 bytes
+LL | | }
+   | |_^ the entire enum is at least 64008 bytes
    |
-LL |     A(bool),
-   |     ^^^^^^^
 note: boxing a variant would require the type no longer be `Copy`
   --> $DIR/large_enum_variant.rs:102:6
    |
@@ -146,20 +180,20 @@ LL | enum CopyableLargeEnum {
 help: consider boxing the large fields to reduce the total size of the enum
   --> $DIR/large_enum_variant.rs:104:5
    |
-LL |     B([u128; 4000]),
-   |     ^^^^^^^^^^^^^^^
+LL |     B([u64; 8000]),
+   |     ^^^^^^^^^^^^^^
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:109:5
+  --> $DIR/large_enum_variant.rs:107:1
    |
-LL |     B([u128; 4000]),
-   |     ^^^^^^^^^^^^^^^ this variant is 64000 bytes
+LL | / enum ManuallyCopyLargeEnum {
+LL | |     A(bool),
+   | |     ------- the second-largest variant contains at least 1 bytes
+LL | |     B([u64; 8000]),
+   | |     -------------- the largest variant contains at least 64000 bytes
+LL | | }
+   | |_^ the entire enum is at least 64008 bytes
    |
-note: and the second-largest variant is 1 bytes:
-  --> $DIR/large_enum_variant.rs:108:5
-   |
-LL |     A(bool),
-   |     ^^^^^^^
 note: boxing a variant would require the type no longer be `Copy`
   --> $DIR/large_enum_variant.rs:107:6
    |
@@ -168,20 +202,20 @@ LL | enum ManuallyCopyLargeEnum {
 help: consider boxing the large fields to reduce the total size of the enum
   --> $DIR/large_enum_variant.rs:109:5
    |
-LL |     B([u128; 4000]),
-   |     ^^^^^^^^^^^^^^^
+LL |     B([u64; 8000]),
+   |     ^^^^^^^^^^^^^^
 
 error: large size difference between variants
-  --> $DIR/large_enum_variant.rs:122:5
+  --> $DIR/large_enum_variant.rs:120:1
    |
-LL |     B([u64; 4000]),
-   |     ^^^^^^^^^^^^^^ this variant is 32000 bytes
+LL | / enum SomeGenericPossiblyCopyEnum<T> {
+LL | |     A(bool, std::marker::PhantomData<T>),
+   | |     ------------------------------------ the second-largest variant contains at least 1 bytes
+LL | |     B([u64; 4000]),
+   | |     -------------- the largest variant contains at least 32000 bytes
+LL | | }
+   | |_^ the entire enum is at least 32008 bytes
    |
-note: and the second-largest variant is 1 bytes:
-  --> $DIR/large_enum_variant.rs:121:5
-   |
-LL |     A(bool, std::marker::PhantomData<T>),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: boxing a variant would require the type no longer be `Copy`
   --> $DIR/large_enum_variant.rs:120:6
    |
@@ -193,5 +227,53 @@ help: consider boxing the large fields to reduce the total size of the enum
 LL |     B([u64; 4000]),
    |     ^^^^^^^^^^^^^^
 
-error: aborting due to 11 previous errors
+error: large size difference between variants
+  --> $DIR/large_enum_variant.rs:133:1
+   |
+LL | / enum LargeEnumWithGenerics<T> {
+LL | |     Small,
+   | |     ----- the second-largest variant carries no data at all
+LL | |     Large((T, [u8; 512])),
+   | |     --------------------- the largest variant contains at least 512 bytes
+LL | | }
+   | |_^ the entire enum is at least 512 bytes
+   |
+help: consider boxing the large fields to reduce the total size of the enum
+   |
+LL |     Large(Box<(T, [u8; 512])>),
+   |           ~~~~~~~~~~~~~~~~~~~
+
+error: large size difference between variants
+  --> $DIR/large_enum_variant.rs:142:1
+   |
+LL | / enum WithGenerics {
+LL | |     Large([Foo<u64>; 64]),
+   | |     --------------------- the largest variant contains at least 512 bytes
+LL | |     Small(u8),
+   | |     --------- the second-largest variant contains at least 1 bytes
+LL | | }
+   | |_^ the entire enum is at least 520 bytes
+   |
+help: consider boxing the large fields to reduce the total size of the enum
+   |
+LL |     Large(Box<[Foo<u64>; 64]>),
+   |           ~~~~~~~~~~~~~~~~~~~
+
+error: large size difference between variants
+  --> $DIR/large_enum_variant.rs:152:1
+   |
+LL | / enum LargeEnumOfConst {
+LL | |     Ok,
+   | |     -- the second-largest variant carries no data at all
+LL | |     Error(PossiblyLargeEnumWithConst<256>),
+   | |     -------------------------------------- the largest variant contains at least 514 bytes
+LL | | }
+   | |_^ the entire enum is at least 514 bytes
+   |
+help: consider boxing the large fields to reduce the total size of the enum
+   |
+LL |     Error(Box<PossiblyLargeEnumWithConst<256>>),
+   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to 16 previous errors
 
diff --git a/src/tools/clippy/tests/ui/large_stack_arrays.rs b/src/tools/clippy/tests/ui/large_stack_arrays.rs
index d9161bfcf154..6790765f803e 100644
--- a/src/tools/clippy/tests/ui/large_stack_arrays.rs
+++ b/src/tools/clippy/tests/ui/large_stack_arrays.rs
@@ -12,6 +12,12 @@ enum E {
     T(u32),
 }
 
+pub static DOESNOTLINT: [u8; 512_001] = [0; 512_001];
+pub static DOESNOTLINT2: [u8; 512_001] = {
+    let x = 0;
+    [x; 512_001]
+};
+
 fn main() {
     let bad = (
         [0u32; 20_000_000],
diff --git a/src/tools/clippy/tests/ui/large_stack_arrays.stderr b/src/tools/clippy/tests/ui/large_stack_arrays.stderr
index 58c0a77c1c84..0d91b65b4284 100644
--- a/src/tools/clippy/tests/ui/large_stack_arrays.stderr
+++ b/src/tools/clippy/tests/ui/large_stack_arrays.stderr
@@ -1,5 +1,5 @@
 error: allocating a local array larger than 512000 bytes
-  --> $DIR/large_stack_arrays.rs:17:9
+  --> $DIR/large_stack_arrays.rs:23:9
    |
 LL |         [0u32; 20_000_000],
    |         ^^^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL |         [0u32; 20_000_000],
    = help: consider allocating on the heap with `vec![0u32; 20_000_000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> $DIR/large_stack_arrays.rs:18:9
+  --> $DIR/large_stack_arrays.rs:24:9
    |
 LL |         [S { data: [0; 32] }; 5000],
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -16,7 +16,7 @@ LL |         [S { data: [0; 32] }; 5000],
    = help: consider allocating on the heap with `vec![S { data: [0; 32] }; 5000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> $DIR/large_stack_arrays.rs:19:9
+  --> $DIR/large_stack_arrays.rs:25:9
    |
 LL |         [Some(""); 20_000_000],
    |         ^^^^^^^^^^^^^^^^^^^^^^
@@ -24,7 +24,7 @@ LL |         [Some(""); 20_000_000],
    = help: consider allocating on the heap with `vec![Some(""); 20_000_000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> $DIR/large_stack_arrays.rs:20:9
+  --> $DIR/large_stack_arrays.rs:26:9
    |
 LL |         [E::T(0); 5000],
    |         ^^^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/len_without_is_empty.rs b/src/tools/clippy/tests/ui/len_without_is_empty.rs
index 1e938e72b577..78397c2af346 100644
--- a/src/tools/clippy/tests/ui/len_without_is_empty.rs
+++ b/src/tools/clippy/tests/ui/len_without_is_empty.rs
@@ -274,7 +274,7 @@ impl AsyncLen {
     }
 
     pub async fn len(&self) -> usize {
-        if self.async_task().await { 0 } else { 1 }
+        usize::from(!self.async_task().await)
     }
 
     pub async fn is_empty(&self) -> bool {
diff --git a/src/tools/clippy/tests/ui/manual_string_new.fixed b/src/tools/clippy/tests/ui/manual_string_new.fixed
new file mode 100644
index 000000000000..a376411bfbc8
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_string_new.fixed
@@ -0,0 +1,63 @@
+// run-rustfix
+
+#![warn(clippy::manual_string_new)]
+
+macro_rules! create_strings_from_macro {
+    // When inside a macro, nothing should warn to prevent false positives.
+    ($some_str:expr) => {
+        let _: String = $some_str.into();
+        let _ = $some_str.to_string();
+    };
+}
+
+fn main() {
+    // Method calls
+    let _ = String::new();
+    let _ = "no warning".to_string();
+
+    let _ = String::new();
+    let _ = "no warning".to_owned();
+
+    let _: String = String::new();
+    let _: String = "no warning".into();
+
+    let _: SomeOtherStruct = "no warning".into();
+    let _: SomeOtherStruct = "".into(); // No warning too. We are not converting into String.
+
+    // Calls
+    let _ = String::new();
+    let _ = String::new();
+    let _ = String::from("no warning");
+    let _ = SomeOtherStruct::from("no warning");
+    let _ = SomeOtherStruct::from(""); // Again: no warning.
+
+    let _ = String::new();
+    let _ = String::try_from("no warning").unwrap();
+    let _ = String::try_from("no warning").expect("this should not warn");
+    let _ = SomeOtherStruct::try_from("no warning").unwrap();
+    let _ = SomeOtherStruct::try_from("").unwrap(); // Again: no warning.
+
+    let _: String = String::new();
+    let _: String = From::from("no warning");
+    let _: SomeOtherStruct = From::from("no warning");
+    let _: SomeOtherStruct = From::from(""); // Again: no warning.
+
+    let _: String = String::new();
+    let _: String = TryFrom::try_from("no warning").unwrap();
+    let _: String = TryFrom::try_from("no warning").expect("this should not warn");
+    let _: String = String::new();
+    let _: SomeOtherStruct = TryFrom::try_from("no_warning").unwrap();
+    let _: SomeOtherStruct = TryFrom::try_from("").unwrap(); // Again: no warning.
+
+    // Macros (never warn)
+    create_strings_from_macro!("");
+    create_strings_from_macro!("Hey");
+}
+
+struct SomeOtherStruct {}
+
+impl From<&str> for SomeOtherStruct {
+    fn from(_value: &str) -> Self {
+        Self {}
+    }
+}
diff --git a/src/tools/clippy/tests/ui/manual_string_new.rs b/src/tools/clippy/tests/ui/manual_string_new.rs
new file mode 100644
index 000000000000..6bfc52fb1bce
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_string_new.rs
@@ -0,0 +1,63 @@
+// run-rustfix
+
+#![warn(clippy::manual_string_new)]
+
+macro_rules! create_strings_from_macro {
+    // When inside a macro, nothing should warn to prevent false positives.
+    ($some_str:expr) => {
+        let _: String = $some_str.into();
+        let _ = $some_str.to_string();
+    };
+}
+
+fn main() {
+    // Method calls
+    let _ = "".to_string();
+    let _ = "no warning".to_string();
+
+    let _ = "".to_owned();
+    let _ = "no warning".to_owned();
+
+    let _: String = "".into();
+    let _: String = "no warning".into();
+
+    let _: SomeOtherStruct = "no warning".into();
+    let _: SomeOtherStruct = "".into(); // No warning too. We are not converting into String.
+
+    // Calls
+    let _ = String::from("");
+    let _ = <String>::from("");
+    let _ = String::from("no warning");
+    let _ = SomeOtherStruct::from("no warning");
+    let _ = SomeOtherStruct::from(""); // Again: no warning.
+
+    let _ = String::try_from("").unwrap();
+    let _ = String::try_from("no warning").unwrap();
+    let _ = String::try_from("no warning").expect("this should not warn");
+    let _ = SomeOtherStruct::try_from("no warning").unwrap();
+    let _ = SomeOtherStruct::try_from("").unwrap(); // Again: no warning.
+
+    let _: String = From::from("");
+    let _: String = From::from("no warning");
+    let _: SomeOtherStruct = From::from("no warning");
+    let _: SomeOtherStruct = From::from(""); // Again: no warning.
+
+    let _: String = TryFrom::try_from("").unwrap();
+    let _: String = TryFrom::try_from("no warning").unwrap();
+    let _: String = TryFrom::try_from("no warning").expect("this should not warn");
+    let _: String = TryFrom::try_from("").expect("this should warn");
+    let _: SomeOtherStruct = TryFrom::try_from("no_warning").unwrap();
+    let _: SomeOtherStruct = TryFrom::try_from("").unwrap(); // Again: no warning.
+
+    // Macros (never warn)
+    create_strings_from_macro!("");
+    create_strings_from_macro!("Hey");
+}
+
+struct SomeOtherStruct {}
+
+impl From<&str> for SomeOtherStruct {
+    fn from(_value: &str) -> Self {
+        Self {}
+    }
+}
diff --git a/src/tools/clippy/tests/ui/manual_string_new.stderr b/src/tools/clippy/tests/ui/manual_string_new.stderr
new file mode 100644
index 000000000000..e5ecfc61947a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_string_new.stderr
@@ -0,0 +1,58 @@
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:15:13
+   |
+LL |     let _ = "".to_string();
+   |             ^^^^^^^^^^^^^^ help: consider using: `String::new()`
+   |
+   = note: `-D clippy::manual-string-new` implied by `-D warnings`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:18:13
+   |
+LL |     let _ = "".to_owned();
+   |             ^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:21:21
+   |
+LL |     let _: String = "".into();
+   |                     ^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:28:13
+   |
+LL |     let _ = String::from("");
+   |             ^^^^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:29:13
+   |
+LL |     let _ = <String>::from("");
+   |             ^^^^^^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:34:13
+   |
+LL |     let _ = String::try_from("").unwrap();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:40:21
+   |
+LL |     let _: String = From::from("");
+   |                     ^^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:45:21
+   |
+LL |     let _: String = TryFrom::try_from("").unwrap();
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: empty String is being created manually
+  --> $DIR/manual_string_new.rs:48:21
+   |
+LL |     let _: String = TryFrom::try_from("").expect("this should warn");
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `String::new()`
+
+error: aborting due to 9 previous errors
+
diff --git a/src/tools/clippy/tests/ui/match_expr_like_matches_macro.fixed b/src/tools/clippy/tests/ui/match_expr_like_matches_macro.fixed
index 1ccbfda64b73..95ca571d07bf 100644
--- a/src/tools/clippy/tests/ui/match_expr_like_matches_macro.fixed
+++ b/src/tools/clippy/tests/ui/match_expr_like_matches_macro.fixed
@@ -167,4 +167,29 @@ fn main() {
             _ => false,
         };
     }
+
+    let x = ' ';
+    // ignore if match block contains comment
+    let _line_comments = match x {
+        // numbers are bad!
+        '1' | '2' | '3' => true,
+        // spaces are very important to be true.
+        ' ' => true,
+        // as are dots
+        '.' => true,
+        _ => false,
+    };
+
+    let _block_comments = match x {
+        /* numbers are bad!
+         */
+        '1' | '2' | '3' => true,
+        /* spaces are very important to be true.
+         */
+        ' ' => true,
+        /* as are dots
+         */
+        '.' => true,
+        _ => false,
+    };
 }
diff --git a/src/tools/clippy/tests/ui/match_expr_like_matches_macro.rs b/src/tools/clippy/tests/ui/match_expr_like_matches_macro.rs
index a49991f59417..3b9c8cadadcc 100644
--- a/src/tools/clippy/tests/ui/match_expr_like_matches_macro.rs
+++ b/src/tools/clippy/tests/ui/match_expr_like_matches_macro.rs
@@ -208,4 +208,29 @@ fn main() {
             _ => false,
         };
     }
+
+    let x = ' ';
+    // ignore if match block contains comment
+    let _line_comments = match x {
+        // numbers are bad!
+        '1' | '2' | '3' => true,
+        // spaces are very important to be true.
+        ' ' => true,
+        // as are dots
+        '.' => true,
+        _ => false,
+    };
+
+    let _block_comments = match x {
+        /* numbers are bad!
+         */
+        '1' | '2' | '3' => true,
+        /* spaces are very important to be true.
+         */
+        ' ' => true,
+        /* as are dots
+         */
+        '.' => true,
+        _ => false,
+    };
 }
diff --git a/src/tools/clippy/tests/ui/match_wild_err_arm.edition2018.stderr b/src/tools/clippy/tests/ui/match_wild_err_arm.edition2018.stderr
index 2a4012039ba9..2d66daea8046 100644
--- a/src/tools/clippy/tests/ui/match_wild_err_arm.edition2018.stderr
+++ b/src/tools/clippy/tests/ui/match_wild_err_arm.edition2018.stderr
@@ -5,7 +5,7 @@ LL |         Err(_) => panic!("err"),
    |         ^^^^^^
    |
    = note: `-D clippy::match-wild-err-arm` implied by `-D warnings`
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: `Err(_)` matches all errors
   --> $DIR/match_wild_err_arm.rs:20:9
@@ -13,7 +13,7 @@ error: `Err(_)` matches all errors
 LL |         Err(_) => panic!(),
    |         ^^^^^^
    |
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: `Err(_)` matches all errors
   --> $DIR/match_wild_err_arm.rs:26:9
@@ -21,7 +21,7 @@ error: `Err(_)` matches all errors
 LL |         Err(_) => {
    |         ^^^^^^
    |
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: `Err(_e)` matches all errors
   --> $DIR/match_wild_err_arm.rs:34:9
@@ -29,7 +29,7 @@ error: `Err(_e)` matches all errors
 LL |         Err(_e) => panic!(),
    |         ^^^^^^^
    |
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/match_wild_err_arm.edition2021.stderr b/src/tools/clippy/tests/ui/match_wild_err_arm.edition2021.stderr
index 2a4012039ba9..2d66daea8046 100644
--- a/src/tools/clippy/tests/ui/match_wild_err_arm.edition2021.stderr
+++ b/src/tools/clippy/tests/ui/match_wild_err_arm.edition2021.stderr
@@ -5,7 +5,7 @@ LL |         Err(_) => panic!("err"),
    |         ^^^^^^
    |
    = note: `-D clippy::match-wild-err-arm` implied by `-D warnings`
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: `Err(_)` matches all errors
   --> $DIR/match_wild_err_arm.rs:20:9
@@ -13,7 +13,7 @@ error: `Err(_)` matches all errors
 LL |         Err(_) => panic!(),
    |         ^^^^^^
    |
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: `Err(_)` matches all errors
   --> $DIR/match_wild_err_arm.rs:26:9
@@ -21,7 +21,7 @@ error: `Err(_)` matches all errors
 LL |         Err(_) => {
    |         ^^^^^^
    |
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: `Err(_e)` matches all errors
   --> $DIR/match_wild_err_arm.rs:34:9
@@ -29,7 +29,7 @@ error: `Err(_e)` matches all errors
 LL |         Err(_e) => panic!(),
    |         ^^^^^^^
    |
-   = note: match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable
+   = note: match each error separately or use the error output, or use `.expect(msg)` if the error case is unreachable
 
 error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/multi_assignments.rs b/src/tools/clippy/tests/ui/multi_assignments.rs
new file mode 100644
index 000000000000..b186bf8bbdb4
--- /dev/null
+++ b/src/tools/clippy/tests/ui/multi_assignments.rs
@@ -0,0 +1,9 @@
+#![warn(clippy::multi_assignments)]
+fn main() {
+    let (mut a, mut b, mut c, mut d) = ((), (), (), ());
+    a = b = c;
+    a = b = c = d;
+    a = b = { c };
+    a = { b = c };
+    a = (b = c);
+}
diff --git a/src/tools/clippy/tests/ui/multi_assignments.stderr b/src/tools/clippy/tests/ui/multi_assignments.stderr
new file mode 100644
index 000000000000..d6c42bb698cf
--- /dev/null
+++ b/src/tools/clippy/tests/ui/multi_assignments.stderr
@@ -0,0 +1,40 @@
+error: assignments don't nest intuitively
+  --> $DIR/multi_assignments.rs:4:5
+   |
+LL |     a = b = c;
+   |     ^^^^^^^^^
+   |
+   = note: `-D clippy::multi-assignments` implied by `-D warnings`
+
+error: assignments don't nest intuitively
+  --> $DIR/multi_assignments.rs:5:5
+   |
+LL |     a = b = c = d;
+   |     ^^^^^^^^^^^^^
+
+error: assignments don't nest intuitively
+  --> $DIR/multi_assignments.rs:5:9
+   |
+LL |     a = b = c = d;
+   |         ^^^^^^^^^
+
+error: assignments don't nest intuitively
+  --> $DIR/multi_assignments.rs:6:5
+   |
+LL |     a = b = { c };
+   |     ^^^^^^^^^^^^^
+
+error: assignments don't nest intuitively
+  --> $DIR/multi_assignments.rs:7:5
+   |
+LL |     a = { b = c };
+   |     ^^^^^^^^^^^^^
+
+error: assignments don't nest intuitively
+  --> $DIR/multi_assignments.rs:8:5
+   |
+LL |     a = (b = c);
+   |     ^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
+
diff --git a/src/tools/clippy/tests/ui/mut_mutex_lock.fixed b/src/tools/clippy/tests/ui/mut_mutex_lock.fixed
index 36bc52e3374e..ecad10a82903 100644
--- a/src/tools/clippy/tests/ui/mut_mutex_lock.fixed
+++ b/src/tools/clippy/tests/ui/mut_mutex_lock.fixed
@@ -18,4 +18,11 @@ fn no_owned_mutex_lock() {
     *value += 1;
 }
 
+fn issue9415() {
+    let mut arc_mutex = Arc::new(Mutex::new(42_u8));
+    let arc_mutex: &mut Arc<Mutex<u8>> = &mut arc_mutex;
+    let mut guard = arc_mutex.lock().unwrap();
+    *guard += 1;
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/mut_mutex_lock.rs b/src/tools/clippy/tests/ui/mut_mutex_lock.rs
index ea60df5ae1bb..f2b1d6fbfbc3 100644
--- a/src/tools/clippy/tests/ui/mut_mutex_lock.rs
+++ b/src/tools/clippy/tests/ui/mut_mutex_lock.rs
@@ -18,4 +18,11 @@ fn no_owned_mutex_lock() {
     *value += 1;
 }
 
+fn issue9415() {
+    let mut arc_mutex = Arc::new(Mutex::new(42_u8));
+    let arc_mutex: &mut Arc<Mutex<u8>> = &mut arc_mutex;
+    let mut guard = arc_mutex.lock().unwrap();
+    *guard += 1;
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/needless_borrow.fixed b/src/tools/clippy/tests/ui/needless_borrow.fixed
index bfd2725ecaaa..8cf93bd24817 100644
--- a/src/tools/clippy/tests/ui/needless_borrow.fixed
+++ b/src/tools/clippy/tests/ui/needless_borrow.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(lint_reasons)]
+#![feature(custom_inner_attributes, lint_reasons)]
 
 #[warn(clippy::all, clippy::needless_borrow)]
 #[allow(unused_variables, clippy::unnecessary_mut_passed)]
@@ -127,6 +127,20 @@ fn main() {
             0
         }
     }
+
+    let _ = std::process::Command::new("ls").args(["-a", "-l"]).status().unwrap();
+    let _ = std::path::Path::new(".").join(".");
+    deref_target_is_x(X);
+    multiple_constraints([[""]]);
+    multiple_constraints_normalizes_to_same(X, X);
+    let _ = Some("").unwrap_or("");
+
+    only_sized(&""); // Don't lint. `Sized` is only bound
+    let _ = std::any::Any::type_id(&""); // Don't lint. `Any` is only bound
+    let _ = Box::new(&""); // Don't lint. Type parameter appears in return type
+    ref_as_ref_path(&""); // Don't lint. Argument type is not a type parameter
+    refs_only(&()); // Don't lint. `&T` implements trait, but `T` doesn't
+    multiple_constraints_normalizes_to_different(&[[""]], &[""]); // Don't lint. Projected type appears in arguments
 }
 
 #[allow(clippy::needless_borrowed_reference)]
@@ -183,3 +197,104 @@ mod issue9160 {
         }
     }
 }
+
+#[derive(Clone, Copy)]
+struct X;
+
+impl std::ops::Deref for X {
+    type Target = X;
+    fn deref(&self) -> &Self::Target {
+        self
+    }
+}
+
+fn deref_target_is_x<T>(_: T)
+where
+    T: std::ops::Deref<Target = X>,
+{
+}
+
+fn multiple_constraints<T, U, V, X, Y>(_: T)
+where
+    T: IntoIterator<Item = U> + IntoIterator<Item = X>,
+    U: IntoIterator<Item = V>,
+    V: AsRef<str>,
+    X: IntoIterator<Item = Y>,
+    Y: AsRef<std::ffi::OsStr>,
+{
+}
+
+fn multiple_constraints_normalizes_to_same<T, U, V>(_: T, _: V)
+where
+    T: std::ops::Deref<Target = U>,
+    U: std::ops::Deref<Target = V>,
+{
+}
+
+fn only_sized<T>(_: T) {}
+
+fn ref_as_ref_path<T: 'static>(_: &'static T)
+where
+    &'static T: AsRef<std::path::Path>,
+{
+}
+
+trait RefsOnly {
+    type Referent;
+}
+
+impl<T> RefsOnly for &T {
+    type Referent = T;
+}
+
+fn refs_only<T, U>(_: T)
+where
+    T: RefsOnly<Referent = U>,
+{
+}
+
+fn multiple_constraints_normalizes_to_different<T, U, V>(_: T, _: U)
+where
+    T: IntoIterator<Item = U>,
+    U: IntoIterator<Item = V>,
+    V: AsRef<str>,
+{
+}
+
+// https://github.com/rust-lang/rust-clippy/pull/9136#pullrequestreview-1037379321
+#[allow(dead_code)]
+mod copyable_iterator {
+    #[derive(Clone, Copy)]
+    struct Iter;
+    impl Iterator for Iter {
+        type Item = ();
+        fn next(&mut self) -> Option<Self::Item> {
+            None
+        }
+    }
+    fn takes_iter(_: impl Iterator) {}
+    fn dont_warn(mut x: Iter) {
+        takes_iter(&mut x);
+    }
+    fn warn(mut x: &mut Iter) {
+        takes_iter(&mut x)
+    }
+}
+
+mod under_msrv {
+    #![allow(dead_code)]
+    #![clippy::msrv = "1.52.0"]
+
+    fn foo() {
+        let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap();
+    }
+}
+
+mod meets_msrv {
+    #![allow(dead_code)]
+    #![clippy::msrv = "1.53.0"]
+
+    fn foo() {
+        let _ = std::process::Command::new("ls").args(["-a", "-l"]).status().unwrap();
+    }
+}
diff --git a/src/tools/clippy/tests/ui/needless_borrow.rs b/src/tools/clippy/tests/ui/needless_borrow.rs
index c457d8c54718..fd9b2a11df96 100644
--- a/src/tools/clippy/tests/ui/needless_borrow.rs
+++ b/src/tools/clippy/tests/ui/needless_borrow.rs
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(lint_reasons)]
+#![feature(custom_inner_attributes, lint_reasons)]
 
 #[warn(clippy::all, clippy::needless_borrow)]
 #[allow(unused_variables, clippy::unnecessary_mut_passed)]
@@ -127,6 +127,20 @@ fn main() {
             0
         }
     }
+
+    let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap();
+    let _ = std::path::Path::new(".").join(&&".");
+    deref_target_is_x(&X);
+    multiple_constraints(&[[""]]);
+    multiple_constraints_normalizes_to_same(&X, X);
+    let _ = Some("").unwrap_or(&"");
+
+    only_sized(&""); // Don't lint. `Sized` is only bound
+    let _ = std::any::Any::type_id(&""); // Don't lint. `Any` is only bound
+    let _ = Box::new(&""); // Don't lint. Type parameter appears in return type
+    ref_as_ref_path(&""); // Don't lint. Argument type is not a type parameter
+    refs_only(&()); // Don't lint. `&T` implements trait, but `T` doesn't
+    multiple_constraints_normalizes_to_different(&[[""]], &[""]); // Don't lint. Projected type appears in arguments
 }
 
 #[allow(clippy::needless_borrowed_reference)]
@@ -183,3 +197,104 @@ mod issue9160 {
         }
     }
 }
+
+#[derive(Clone, Copy)]
+struct X;
+
+impl std::ops::Deref for X {
+    type Target = X;
+    fn deref(&self) -> &Self::Target {
+        self
+    }
+}
+
+fn deref_target_is_x<T>(_: T)
+where
+    T: std::ops::Deref<Target = X>,
+{
+}
+
+fn multiple_constraints<T, U, V, X, Y>(_: T)
+where
+    T: IntoIterator<Item = U> + IntoIterator<Item = X>,
+    U: IntoIterator<Item = V>,
+    V: AsRef<str>,
+    X: IntoIterator<Item = Y>,
+    Y: AsRef<std::ffi::OsStr>,
+{
+}
+
+fn multiple_constraints_normalizes_to_same<T, U, V>(_: T, _: V)
+where
+    T: std::ops::Deref<Target = U>,
+    U: std::ops::Deref<Target = V>,
+{
+}
+
+fn only_sized<T>(_: T) {}
+
+fn ref_as_ref_path<T: 'static>(_: &'static T)
+where
+    &'static T: AsRef<std::path::Path>,
+{
+}
+
+trait RefsOnly {
+    type Referent;
+}
+
+impl<T> RefsOnly for &T {
+    type Referent = T;
+}
+
+fn refs_only<T, U>(_: T)
+where
+    T: RefsOnly<Referent = U>,
+{
+}
+
+fn multiple_constraints_normalizes_to_different<T, U, V>(_: T, _: U)
+where
+    T: IntoIterator<Item = U>,
+    U: IntoIterator<Item = V>,
+    V: AsRef<str>,
+{
+}
+
+// https://github.com/rust-lang/rust-clippy/pull/9136#pullrequestreview-1037379321
+#[allow(dead_code)]
+mod copyable_iterator {
+    #[derive(Clone, Copy)]
+    struct Iter;
+    impl Iterator for Iter {
+        type Item = ();
+        fn next(&mut self) -> Option<Self::Item> {
+            None
+        }
+    }
+    fn takes_iter(_: impl Iterator) {}
+    fn dont_warn(mut x: Iter) {
+        takes_iter(&mut x);
+    }
+    fn warn(mut x: &mut Iter) {
+        takes_iter(&mut x)
+    }
+}
+
+mod under_msrv {
+    #![allow(dead_code)]
+    #![clippy::msrv = "1.52.0"]
+
+    fn foo() {
+        let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap();
+    }
+}
+
+mod meets_msrv {
+    #![allow(dead_code)]
+    #![clippy::msrv = "1.53.0"]
+
+    fn foo() {
+        let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap();
+    }
+}
diff --git a/src/tools/clippy/tests/ui/needless_borrow.stderr b/src/tools/clippy/tests/ui/needless_borrow.stderr
index 66588689d818..5af68706d4ba 100644
--- a/src/tools/clippy/tests/ui/needless_borrow.stderr
+++ b/src/tools/clippy/tests/ui/needless_borrow.stderr
@@ -120,17 +120,59 @@ error: this expression creates a reference which is immediately dereferenced by
 LL |     (&&5).foo();
    |     ^^^^^ help: change this to: `(&5)`
 
+error: the borrowed expression implements the required traits
+  --> $DIR/needless_borrow.rs:131:51
+   |
+LL |     let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap();
+   |                                                   ^^^^^^^^^^^^^ help: change this to: `["-a", "-l"]`
+
+error: the borrowed expression implements the required traits
+  --> $DIR/needless_borrow.rs:132:44
+   |
+LL |     let _ = std::path::Path::new(".").join(&&".");
+   |                                            ^^^^^ help: change this to: `"."`
+
+error: the borrowed expression implements the required traits
+  --> $DIR/needless_borrow.rs:133:23
+   |
+LL |     deref_target_is_x(&X);
+   |                       ^^ help: change this to: `X`
+
+error: the borrowed expression implements the required traits
+  --> $DIR/needless_borrow.rs:134:26
+   |
+LL |     multiple_constraints(&[[""]]);
+   |                          ^^^^^^^ help: change this to: `[[""]]`
+
+error: the borrowed expression implements the required traits
+  --> $DIR/needless_borrow.rs:135:45
+   |
+LL |     multiple_constraints_normalizes_to_same(&X, X);
+   |                                             ^^ help: change this to: `X`
+
+error: this expression creates a reference which is immediately dereferenced by the compiler
+  --> $DIR/needless_borrow.rs:136:32
+   |
+LL |     let _ = Some("").unwrap_or(&"");
+   |                                ^^^ help: change this to: `""`
+
 error: this expression borrows a value the compiler would automatically borrow
-  --> $DIR/needless_borrow.rs:173:13
+  --> $DIR/needless_borrow.rs:187:13
    |
 LL |             (&self.f)()
    |             ^^^^^^^^^ help: change this to: `(self.f)`
 
 error: this expression borrows a value the compiler would automatically borrow
-  --> $DIR/needless_borrow.rs:182:13
+  --> $DIR/needless_borrow.rs:196:13
    |
 LL |             (&mut self.f)()
    |             ^^^^^^^^^^^^^ help: change this to: `(self.f)`
 
-error: aborting due to 22 previous errors
+error: the borrowed expression implements the required traits
+  --> $DIR/needless_borrow.rs:298:55
+   |
+LL |         let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap();
+   |                                                       ^^^^^^^^^^^^^ help: change this to: `["-a", "-l"]`
+
+error: aborting due to 29 previous errors
 
diff --git a/src/tools/clippy/tests/ui/needless_collect_indirect.rs b/src/tools/clippy/tests/ui/needless_collect_indirect.rs
index 1f11d1f8d563..12a9ace1ee68 100644
--- a/src/tools/clippy/tests/ui/needless_collect_indirect.rs
+++ b/src/tools/clippy/tests/ui/needless_collect_indirect.rs
@@ -112,3 +112,192 @@ fn allow_test() {
     let v = [1].iter().collect::<Vec<_>>();
     v.into_iter().collect::<HashSet<_>>();
 }
+
+mod issue_8553 {
+    fn test_for() {
+        let vec = vec![1, 2];
+        let w: Vec<usize> = vec.iter().map(|i| i * i).collect();
+
+        for i in 0..2 {
+            // Do not lint, because this method call is in the loop
+            w.contains(&i);
+        }
+
+        for i in 0..2 {
+            let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+            let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+            // Do lint
+            y.contains(&i);
+            for j in 0..2 {
+                // Do not lint, because this method call is in the loop
+                z.contains(&j);
+            }
+        }
+
+        // Do not lint, because this variable is used.
+        w.contains(&0);
+    }
+
+    fn test_while() {
+        let vec = vec![1, 2];
+        let x: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let mut n = 0;
+        while n > 1 {
+            // Do not lint, because this method call is in the loop
+            x.contains(&n);
+            n += 1;
+        }
+
+        while n > 2 {
+            let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+            let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+            // Do lint
+            y.contains(&n);
+            n += 1;
+            while n > 4 {
+                // Do not lint, because this method call is in the loop
+                z.contains(&n);
+                n += 1;
+            }
+        }
+    }
+
+    fn test_loop() {
+        let vec = vec![1, 2];
+        let x: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let mut n = 0;
+        loop {
+            if n < 1 {
+                // Do not lint, because this method call is in the loop
+                x.contains(&n);
+                n += 1;
+            } else {
+                break;
+            }
+        }
+
+        loop {
+            if n < 2 {
+                let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+                let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+                // Do lint
+                y.contains(&n);
+                n += 1;
+                loop {
+                    if n < 4 {
+                        // Do not lint, because this method call is in the loop
+                        z.contains(&n);
+                        n += 1;
+                    } else {
+                        break;
+                    }
+                }
+            } else {
+                break;
+            }
+        }
+    }
+
+    fn test_while_let() {
+        let vec = vec![1, 2];
+        let x: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let optional = Some(0);
+        let mut n = 0;
+        while let Some(value) = optional {
+            if n < 1 {
+                // Do not lint, because this method call is in the loop
+                x.contains(&n);
+                n += 1;
+            } else {
+                break;
+            }
+        }
+
+        while let Some(value) = optional {
+            let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+            let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+            if n < 2 {
+                // Do lint
+                y.contains(&n);
+                n += 1;
+            } else {
+                break;
+            }
+
+            while let Some(value) = optional {
+                if n < 4 {
+                    // Do not lint, because this method call is in the loop
+                    z.contains(&n);
+                    n += 1;
+                } else {
+                    break;
+                }
+            }
+        }
+    }
+
+    fn test_if_cond() {
+        let vec = vec![1, 2];
+        let v: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let w = v.iter().collect::<Vec<_>>();
+        // Do lint
+        for _ in 0..w.len() {
+            todo!();
+        }
+    }
+
+    fn test_if_cond_false_case() {
+        let vec = vec![1, 2];
+        let v: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let w = v.iter().collect::<Vec<_>>();
+        // Do not lint, because w is used.
+        for _ in 0..w.len() {
+            todo!();
+        }
+
+        w.len();
+    }
+
+    fn test_while_cond() {
+        let mut vec = vec![1, 2];
+        let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let mut w = v.iter().collect::<Vec<_>>();
+        // Do lint
+        while 1 == w.len() {
+            todo!();
+        }
+    }
+
+    fn test_while_cond_false_case() {
+        let mut vec = vec![1, 2];
+        let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let mut w = v.iter().collect::<Vec<_>>();
+        // Do not lint, because w is used.
+        while 1 == w.len() {
+            todo!();
+        }
+
+        w.len();
+    }
+
+    fn test_while_let_cond() {
+        let mut vec = vec![1, 2];
+        let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let mut w = v.iter().collect::<Vec<_>>();
+        // Do lint
+        while let Some(i) = Some(w.len()) {
+            todo!();
+        }
+    }
+
+    fn test_while_let_cond_false_case() {
+        let mut vec = vec![1, 2];
+        let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
+        let mut w = v.iter().collect::<Vec<_>>();
+        // Do not lint, because w is used.
+        while let Some(i) = Some(w.len()) {
+            todo!();
+        }
+        w.len();
+    }
+}
diff --git a/src/tools/clippy/tests/ui/needless_collect_indirect.stderr b/src/tools/clippy/tests/ui/needless_collect_indirect.stderr
index 0f5e78f91198..9f0880cc6069 100644
--- a/src/tools/clippy/tests/ui/needless_collect_indirect.stderr
+++ b/src/tools/clippy/tests/ui/needless_collect_indirect.stderr
@@ -125,5 +125,122 @@ LL ~
 LL ~         sample.iter().count()
    |
 
-error: aborting due to 9 previous errors
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:127:59
+   |
+LL |             let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+   |                                                           ^^^^^^^
+...
+LL |             y.contains(&i);
+   |             -------------- the iterator could be used here instead
+   |
+help: check if the original Iterator contains an element instead of collecting then checking
+   |
+LL ~             
+LL |             let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+LL |             // Do lint
+LL ~             vec.iter().map(|k| k * k).any(|x| x == i);
+   |
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:152:59
+   |
+LL |             let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+   |                                                           ^^^^^^^
+...
+LL |             y.contains(&n);
+   |             -------------- the iterator could be used here instead
+   |
+help: check if the original Iterator contains an element instead of collecting then checking
+   |
+LL ~             
+LL |             let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+LL |             // Do lint
+LL ~             vec.iter().map(|k| k * k).any(|x| x == n);
+   |
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:181:63
+   |
+LL |                 let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+   |                                                               ^^^^^^^
+...
+LL |                 y.contains(&n);
+   |                 -------------- the iterator could be used here instead
+   |
+help: check if the original Iterator contains an element instead of collecting then checking
+   |
+LL ~                 
+LL |                 let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+LL |                 // Do lint
+LL ~                 vec.iter().map(|k| k * k).any(|x| x == n);
+   |
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:217:59
+   |
+LL |             let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
+   |                                                           ^^^^^^^
+...
+LL |                 y.contains(&n);
+   |                 -------------- the iterator could be used here instead
+   |
+help: check if the original Iterator contains an element instead of collecting then checking
+   |
+LL ~             
+LL |             let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
+LL |             if n < 2 {
+LL |                 // Do lint
+LL ~                 vec.iter().map(|k| k * k).any(|x| x == n);
+   |
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:242:26
+   |
+LL |         let w = v.iter().collect::<Vec<_>>();
+   |                          ^^^^^^^
+LL |         // Do lint
+LL |         for _ in 0..w.len() {
+   |                     ------- the iterator could be used here instead
+   |
+help: take the original Iterator's count instead of collecting it and finding the length
+   |
+LL ~         
+LL |         // Do lint
+LL ~         for _ in 0..v.iter().count() {
+   |
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:264:30
+   |
+LL |         let mut w = v.iter().collect::<Vec<_>>();
+   |                              ^^^^^^^
+LL |         // Do lint
+LL |         while 1 == w.len() {
+   |                    ------- the iterator could be used here instead
+   |
+help: take the original Iterator's count instead of collecting it and finding the length
+   |
+LL ~         
+LL |         // Do lint
+LL ~         while 1 == v.iter().count() {
+   |
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect_indirect.rs:286:30
+   |
+LL |         let mut w = v.iter().collect::<Vec<_>>();
+   |                              ^^^^^^^
+LL |         // Do lint
+LL |         while let Some(i) = Some(w.len()) {
+   |                                  ------- the iterator could be used here instead
+   |
+help: take the original Iterator's count instead of collecting it and finding the length
+   |
+LL ~         
+LL |         // Do lint
+LL ~         while let Some(i) = Some(v.iter().count()) {
+   |
+
+error: aborting due to 16 previous errors
 
diff --git a/src/tools/clippy/tests/ui/needless_match.fixed b/src/tools/clippy/tests/ui/needless_match.fixed
index 0c9178fb85ef..7e47406798cf 100644
--- a/src/tools/clippy/tests/ui/needless_match.fixed
+++ b/src/tools/clippy/tests/ui/needless_match.fixed
@@ -207,4 +207,43 @@ impl Tr for Result<i32, i32> {
     }
 }
 
+mod issue9084 {
+    fn wildcard_if() {
+        let mut some_bool = true;
+        let e = Some(1);
+
+        // should lint
+        let _ = e;
+
+        // should lint
+        let _ = e;
+
+        // should not lint
+        let _ = match e {
+            _ if some_bool => e,
+            _ => Some(2),
+        };
+
+        // should not lint
+        let _ = match e {
+            Some(i) => Some(i + 1),
+            _ if some_bool => e,
+            _ => e,
+        };
+
+        // should not lint (guard has side effects)
+        let _ = match e {
+            Some(i) => Some(i),
+            _ if {
+                some_bool = false;
+                some_bool
+            } =>
+            {
+                e
+            },
+            _ => e,
+        };
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/needless_match.rs b/src/tools/clippy/tests/ui/needless_match.rs
index f66f01d7ccaf..809c694bf400 100644
--- a/src/tools/clippy/tests/ui/needless_match.rs
+++ b/src/tools/clippy/tests/ui/needless_match.rs
@@ -244,4 +244,50 @@ impl Tr for Result<i32, i32> {
     }
 }
 
+mod issue9084 {
+    fn wildcard_if() {
+        let mut some_bool = true;
+        let e = Some(1);
+
+        // should lint
+        let _ = match e {
+            _ if some_bool => e,
+            _ => e,
+        };
+
+        // should lint
+        let _ = match e {
+            Some(i) => Some(i),
+            _ if some_bool => e,
+            _ => e,
+        };
+
+        // should not lint
+        let _ = match e {
+            _ if some_bool => e,
+            _ => Some(2),
+        };
+
+        // should not lint
+        let _ = match e {
+            Some(i) => Some(i + 1),
+            _ if some_bool => e,
+            _ => e,
+        };
+
+        // should not lint (guard has side effects)
+        let _ = match e {
+            Some(i) => Some(i),
+            _ if {
+                some_bool = false;
+                some_bool
+            } =>
+            {
+                e
+            },
+            _ => e,
+        };
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/needless_match.stderr b/src/tools/clippy/tests/ui/needless_match.stderr
index 5bc79800a1a7..28e78441c252 100644
--- a/src/tools/clippy/tests/ui/needless_match.stderr
+++ b/src/tools/clippy/tests/ui/needless_match.stderr
@@ -109,5 +109,26 @@ LL | |             Complex::D(E::VariantB(ea, eb), b) => Complex::D(E::VariantB(
 LL | |         };
    | |_________^ help: replace it with: `ce`
 
-error: aborting due to 11 previous errors
+error: this match expression is unnecessary
+  --> $DIR/needless_match.rs:253:17
+   |
+LL |           let _ = match e {
+   |  _________________^
+LL | |             _ if some_bool => e,
+LL | |             _ => e,
+LL | |         };
+   | |_________^ help: replace it with: `e`
+
+error: this match expression is unnecessary
+  --> $DIR/needless_match.rs:259:17
+   |
+LL |           let _ = match e {
+   |  _________________^
+LL | |             Some(i) => Some(i),
+LL | |             _ if some_bool => e,
+LL | |             _ => e,
+LL | |         };
+   | |_________^ help: replace it with: `e`
+
+error: aborting due to 13 previous errors
 
diff --git a/src/tools/clippy/tests/ui/needless_return.fixed b/src/tools/clippy/tests/ui/needless_return.fixed
index 0bc0d0011efe..695883e8dff7 100644
--- a/src/tools/clippy/tests/ui/needless_return.fixed
+++ b/src/tools/clippy/tests/ui/needless_return.fixed
@@ -1,7 +1,6 @@
 // run-rustfix
 
 #![feature(lint_reasons)]
-#![feature(let_else)]
 #![allow(unused)]
 #![allow(
     clippy::if_same_then_else,
@@ -228,13 +227,9 @@ fn needless_return_macro() -> String {
     format!("Hello {}", "world!")
 }
 
-fn check_expect() -> bool {
-    if true {
-        // no error!
-        return true;
-    }
-    #[expect(clippy::needless_return)]
-    return true;
+fn issue_9361() -> i32 {
+    #[allow(clippy::integer_arithmetic)]
+    return 1 + 2;
 }
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/needless_return.rs b/src/tools/clippy/tests/ui/needless_return.rs
index eb9f72e8e782..63d9fe9ecdf8 100644
--- a/src/tools/clippy/tests/ui/needless_return.rs
+++ b/src/tools/clippy/tests/ui/needless_return.rs
@@ -1,7 +1,6 @@
 // run-rustfix
 
 #![feature(lint_reasons)]
-#![feature(let_else)]
 #![allow(unused)]
 #![allow(
     clippy::if_same_then_else,
@@ -228,13 +227,9 @@ fn needless_return_macro() -> String {
     return format!("Hello {}", "world!");
 }
 
-fn check_expect() -> bool {
-    if true {
-        // no error!
-        return true;
-    }
-    #[expect(clippy::needless_return)]
-    return true;
+fn issue_9361() -> i32 {
+    #[allow(clippy::integer_arithmetic)]
+    return 1 + 2;
 }
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/needless_return.stderr b/src/tools/clippy/tests/ui/needless_return.stderr
index 83ff07638693..cadee6e00dff 100644
--- a/src/tools/clippy/tests/ui/needless_return.stderr
+++ b/src/tools/clippy/tests/ui/needless_return.stderr
@@ -1,5 +1,5 @@
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:27:5
+  --> $DIR/needless_return.rs:26:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
@@ -7,217 +7,217 @@ LL |     return true;
    = note: `-D clippy::needless-return` implied by `-D warnings`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:31:5
+  --> $DIR/needless_return.rs:30:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:36:9
+  --> $DIR/needless_return.rs:35:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:38:9
+  --> $DIR/needless_return.rs:37:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:44:17
+  --> $DIR/needless_return.rs:43:17
    |
 LL |         true => return false,
    |                 ^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:46:13
+  --> $DIR/needless_return.rs:45:13
    |
 LL |             return true;
    |             ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:53:9
+  --> $DIR/needless_return.rs:52:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:55:16
+  --> $DIR/needless_return.rs:54:16
    |
 LL |     let _ = || return true;
    |                ^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:59:5
+  --> $DIR/needless_return.rs:58:5
    |
 LL |     return the_answer!();
    |     ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `the_answer!()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:63:5
+  --> $DIR/needless_return.rs:62:5
    |
 LL |     return;
    |     ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:68:9
+  --> $DIR/needless_return.rs:67:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:70:9
+  --> $DIR/needless_return.rs:69:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:77:14
+  --> $DIR/needless_return.rs:76:14
    |
 LL |         _ => return,
    |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:86:13
+  --> $DIR/needless_return.rs:85:13
    |
 LL |             return;
    |             ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:88:14
+  --> $DIR/needless_return.rs:87:14
    |
 LL |         _ => return,
    |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:101:9
+  --> $DIR/needless_return.rs:100:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:103:9
+  --> $DIR/needless_return.rs:102:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:125:32
+  --> $DIR/needless_return.rs:124:32
    |
 LL |         bar.unwrap_or_else(|_| return)
    |                                ^^^^^^ help: replace `return` with an empty block: `{}`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:130:13
+  --> $DIR/needless_return.rs:129:13
    |
 LL |             return;
    |             ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:132:20
+  --> $DIR/needless_return.rs:131:20
    |
 LL |         let _ = || return;
    |                    ^^^^^^ help: replace `return` with an empty block: `{}`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:138:32
+  --> $DIR/needless_return.rs:137:32
    |
 LL |         res.unwrap_or_else(|_| return Foo)
    |                                ^^^^^^^^^^ help: remove `return`: `Foo`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:147:5
+  --> $DIR/needless_return.rs:146:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:151:5
+  --> $DIR/needless_return.rs:150:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:156:9
+  --> $DIR/needless_return.rs:155:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:158:9
+  --> $DIR/needless_return.rs:157:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:164:17
+  --> $DIR/needless_return.rs:163:17
    |
 LL |         true => return false,
    |                 ^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:166:13
+  --> $DIR/needless_return.rs:165:13
    |
 LL |             return true;
    |             ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:173:9
+  --> $DIR/needless_return.rs:172:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:175:16
+  --> $DIR/needless_return.rs:174:16
    |
 LL |     let _ = || return true;
    |                ^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:179:5
+  --> $DIR/needless_return.rs:178:5
    |
 LL |     return the_answer!();
    |     ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `the_answer!()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:183:5
+  --> $DIR/needless_return.rs:182:5
    |
 LL |     return;
    |     ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:188:9
+  --> $DIR/needless_return.rs:187:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:190:9
+  --> $DIR/needless_return.rs:189:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:197:14
+  --> $DIR/needless_return.rs:196:14
    |
 LL |         _ => return,
    |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:210:9
+  --> $DIR/needless_return.rs:209:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:212:9
+  --> $DIR/needless_return.rs:211:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:228:5
+  --> $DIR/needless_return.rs:227:5
    |
 LL |     return format!("Hello {}", "world!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `format!("Hello {}", "world!")`
diff --git a/src/tools/clippy/tests/ui/nonminimal_bool.rs b/src/tools/clippy/tests/ui/nonminimal_bool.rs
index 24ae62bb0588..e9b4367ca653 100644
--- a/src/tools/clippy/tests/ui/nonminimal_bool.rs
+++ b/src/tools/clippy/tests/ui/nonminimal_bool.rs
@@ -57,3 +57,9 @@ fn check_expect() {
     #[expect(clippy::nonminimal_bool)]
     let _ = !!a;
 }
+
+fn issue9428() {
+    if matches!(true, true) && true {
+        println!("foo");
+    }
+}
diff --git a/src/tools/clippy/tests/ui/nonminimal_bool.stderr b/src/tools/clippy/tests/ui/nonminimal_bool.stderr
index fc6a5ce1dc2e..91b5805aa97a 100644
--- a/src/tools/clippy/tests/ui/nonminimal_bool.stderr
+++ b/src/tools/clippy/tests/ui/nonminimal_bool.stderr
@@ -107,5 +107,11 @@ LL |     let _ = !(a == b || c == d);
 LL |     let _ = a != b && c != d;
    |             ~~~~~~~~~~~~~~~~
 
-error: aborting due to 12 previous errors
+error: this boolean expression can be simplified
+  --> $DIR/nonminimal_bool.rs:62:8
+   |
+LL |     if matches!(true, true) && true {
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `matches!(true, true)`
+
+error: aborting due to 13 previous errors
 
diff --git a/src/tools/clippy/tests/ui/only_used_in_recursion.rs b/src/tools/clippy/tests/ui/only_used_in_recursion.rs
index 5768434f988e..f71e8ead5195 100644
--- a/src/tools/clippy/tests/ui/only_used_in_recursion.rs
+++ b/src/tools/clippy/tests/ui/only_used_in_recursion.rs
@@ -1,122 +1,113 @@
 #![warn(clippy::only_used_in_recursion)]
 
-fn simple(a: usize, b: usize) -> usize {
-    if a == 0 { 1 } else { simple(a - 1, b) }
+fn _simple(x: u32) -> u32 {
+    x
 }
 
-fn with_calc(a: usize, b: isize) -> usize {
-    if a == 0 { 1 } else { with_calc(a - 1, -b + 1) }
+fn _simple2(x: u32) -> u32 {
+    _simple(x)
 }
 
-fn tuple((a, b): (usize, usize)) -> usize {
-    if a == 0 { 1 } else { tuple((a - 1, b + 1)) }
+fn _one_unused(flag: u32, a: usize) -> usize {
+    if flag == 0 { 0 } else { _one_unused(flag - 1, a) }
 }
 
-fn let_tuple(a: usize, b: usize) -> usize {
-    let (c, d) = (a, b);
-    if c == 0 { 1 } else { let_tuple(c - 1, d + 1) }
+fn _two_unused(flag: u32, a: u32, b: i32) -> usize {
+    if flag == 0 { 0 } else { _two_unused(flag - 1, a, b) }
 }
 
-fn array([a, b]: [usize; 2]) -> usize {
-    if a == 0 { 1 } else { array([a - 1, b + 1]) }
+fn _with_calc(flag: u32, a: i64) -> usize {
+    if flag == 0 {
+        0
+    } else {
+        _with_calc(flag - 1, (-a + 10) * 5)
+    }
 }
 
-fn index(a: usize, mut b: &[usize], c: usize) -> usize {
-    if a == 0 { 1 } else { index(a - 1, b, c + b[0]) }
+// Don't lint
+fn _used_with_flag(flag: u32, a: u32) -> usize {
+    if flag == 0 { 0 } else { _used_with_flag(flag ^ a, a - 1) }
 }
 
-fn break_(a: usize, mut b: usize, mut c: usize) -> usize {
-    let c = loop {
-        b += 1;
-        c += 1;
-        if c == 10 {
-            break b;
-        }
-    };
-
-    if a == 0 { 1 } else { break_(a - 1, c, c) }
+fn _used_with_unused(flag: u32, a: i32, b: i32) -> usize {
+    if flag == 0 {
+        0
+    } else {
+        _used_with_unused(flag - 1, -a, a + b)
+    }
 }
 
-// this has a side effect
-fn mut_ref(a: usize, b: &mut usize) -> usize {
-    *b = 1;
-    if a == 0 { 1 } else { mut_ref(a - 1, b) }
+fn _codependent_unused(flag: u32, a: i32, b: i32) -> usize {
+    if flag == 0 {
+        0
+    } else {
+        _codependent_unused(flag - 1, a * b, a + b)
+    }
 }
 
-fn mut_ref2(a: usize, b: &mut usize) -> usize {
-    let mut c = *b;
-    if a == 0 { 1 } else { mut_ref2(a - 1, &mut c) }
-}
-
-fn not_primitive(a: usize, b: String) -> usize {
-    if a == 0 { 1 } else { not_primitive(a - 1, b) }
-}
-
-// this doesn't have a side effect,
-// but `String` is not primitive.
-fn not_primitive_op(a: usize, b: String, c: &str) -> usize {
-    if a == 1 { 1 } else { not_primitive_op(a, b + c, c) }
+fn _not_primitive(flag: u32, b: String) -> usize {
+    if flag == 0 { 0 } else { _not_primitive(flag - 1, b) }
 }
 
 struct A;
 
 impl A {
-    fn method(a: usize, b: usize) -> usize {
-        if a == 0 { 1 } else { A::method(a - 1, b - 1) }
+    fn _method(flag: usize, a: usize) -> usize {
+        if flag == 0 { 0 } else { Self::_method(flag - 1, a) }
     }
 
-    fn method2(&self, a: usize, b: usize) -> usize {
-        if a == 0 { 1 } else { self.method2(a - 1, b + 1) }
+    fn _method_self(&self, flag: usize, a: usize) -> usize {
+        if flag == 0 { 0 } else { self._method_self(flag - 1, a) }
     }
 }
 
 trait B {
-    fn hello(a: usize, b: usize) -> usize;
-
-    fn hello2(&self, a: usize, b: usize) -> usize;
+    fn method(flag: u32, a: usize) -> usize;
+    fn method_self(&self, flag: u32, a: usize) -> usize;
 }
 
 impl B for A {
-    fn hello(a: usize, b: usize) -> usize {
-        if a == 0 { 1 } else { A::hello(a - 1, b + 1) }
+    fn method(flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { Self::method(flag - 1, a) }
     }
 
-    fn hello2(&self, a: usize, b: usize) -> usize {
-        if a == 0 { 1 } else { self.hello2(a - 1, b + 1) }
+    fn method_self(&self, flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { self.method_self(flag - 1, a) }
+    }
+}
+
+impl B for () {
+    fn method(flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { a }
+    }
+
+    fn method_self(&self, flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { a }
+    }
+}
+
+impl B for u32 {
+    fn method(flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { <() as B>::method(flag, a) }
+    }
+
+    fn method_self(&self, flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { ().method_self(flag, a) }
     }
 }
 
 trait C {
-    fn hello(a: usize, b: usize) -> usize {
-        if a == 0 { 1 } else { Self::hello(a - 1, b + 1) }
+    fn method(flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { Self::method(flag - 1, a) }
     }
 
-    fn hello2(&self, a: usize, b: usize) -> usize {
-        if a == 0 { 1 } else { self.hello2(a - 1, b + 1) }
+    fn method_self(&self, flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { self.method_self(flag - 1, a) }
     }
 }
 
-fn ignore(a: usize, _: usize) -> usize {
-    if a == 1 { 1 } else { ignore(a - 1, 0) }
-}
-
-fn ignore2(a: usize, _b: usize) -> usize {
-    if a == 1 { 1 } else { ignore2(a - 1, _b) }
-}
-
-fn f1(a: u32) -> u32 {
-    a
-}
-
-fn f2(a: u32) -> u32 {
-    f1(a)
-}
-
-fn inner_fn(a: u32) -> u32 {
-    fn inner_fn(a: u32) -> u32 {
-        a
-    }
-    inner_fn(a)
+fn _ignore(flag: usize, _a: usize) -> usize {
+    if flag == 0 { 0 } else { _ignore(flag - 1, _a) }
 }
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/only_used_in_recursion.stderr b/src/tools/clippy/tests/ui/only_used_in_recursion.stderr
index 6fe9361bf5fe..74057ddcfda4 100644
--- a/src/tools/clippy/tests/ui/only_used_in_recursion.stderr
+++ b/src/tools/clippy/tests/ui/only_used_in_recursion.stderr
@@ -1,82 +1,195 @@
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:3:21
+  --> $DIR/only_used_in_recursion.rs:11:27
    |
-LL | fn simple(a: usize, b: usize) -> usize {
-   |                     ^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _one_unused(flag: u32, a: usize) -> usize {
+   |                           ^ help: if this is intentional, prefix it with an underscore: `_a`
    |
    = note: `-D clippy::only-used-in-recursion` implied by `-D warnings`
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:12:53
+   |
+LL |     if flag == 0 { 0 } else { _one_unused(flag - 1, a) }
+   |                                                     ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:7:24
+  --> $DIR/only_used_in_recursion.rs:15:27
    |
-LL | fn with_calc(a: usize, b: isize) -> usize {
-   |                        ^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _two_unused(flag: u32, a: u32, b: i32) -> usize {
+   |                           ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:16:53
+   |
+LL |     if flag == 0 { 0 } else { _two_unused(flag - 1, a, b) }
+   |                                                     ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:11:14
+  --> $DIR/only_used_in_recursion.rs:15:35
    |
-LL | fn tuple((a, b): (usize, usize)) -> usize {
-   |              ^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _two_unused(flag: u32, a: u32, b: i32) -> usize {
+   |                                   ^ help: if this is intentional, prefix it with an underscore: `_b`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:16:56
+   |
+LL |     if flag == 0 { 0 } else { _two_unused(flag - 1, a, b) }
+   |                                                        ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:15:24
+  --> $DIR/only_used_in_recursion.rs:19:26
    |
-LL | fn let_tuple(a: usize, b: usize) -> usize {
-   |                        ^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _with_calc(flag: u32, a: i64) -> usize {
+   |                          ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:23:32
+   |
+LL |         _with_calc(flag - 1, (-a + 10) * 5)
+   |                                ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:20:14
+  --> $DIR/only_used_in_recursion.rs:32:33
    |
-LL | fn array([a, b]: [usize; 2]) -> usize {
-   |              ^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _used_with_unused(flag: u32, a: i32, b: i32) -> usize {
+   |                                 ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:36:38
+   |
+LL |         _used_with_unused(flag - 1, -a, a + b)
+   |                                      ^  ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:24:20
+  --> $DIR/only_used_in_recursion.rs:32:41
    |
-LL | fn index(a: usize, mut b: &[usize], c: usize) -> usize {
-   |                    ^^^^^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _used_with_unused(flag: u32, a: i32, b: i32) -> usize {
+   |                                         ^ help: if this is intentional, prefix it with an underscore: `_b`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:36:45
+   |
+LL |         _used_with_unused(flag - 1, -a, a + b)
+   |                                             ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:24:37
+  --> $DIR/only_used_in_recursion.rs:40:35
    |
-LL | fn index(a: usize, mut b: &[usize], c: usize) -> usize {
-   |                                     ^ help: if this is intentional, prefix with an underscore: `_c`
+LL | fn _codependent_unused(flag: u32, a: i32, b: i32) -> usize {
+   |                                   ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:44:39
+   |
+LL |         _codependent_unused(flag - 1, a * b, a + b)
+   |                                       ^      ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:28:21
+  --> $DIR/only_used_in_recursion.rs:40:43
    |
-LL | fn break_(a: usize, mut b: usize, mut c: usize) -> usize {
-   |                     ^^^^^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _codependent_unused(flag: u32, a: i32, b: i32) -> usize {
+   |                                           ^ help: if this is intentional, prefix it with an underscore: `_b`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:44:43
+   |
+LL |         _codependent_unused(flag - 1, a * b, a + b)
+   |                                           ^      ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:46:23
+  --> $DIR/only_used_in_recursion.rs:48:30
    |
-LL | fn mut_ref2(a: usize, b: &mut usize) -> usize {
-   |                       ^ help: if this is intentional, prefix with an underscore: `_b`
+LL | fn _not_primitive(flag: u32, b: String) -> usize {
+   |                              ^ help: if this is intentional, prefix it with an underscore: `_b`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:49:56
+   |
+LL |     if flag == 0 { 0 } else { _not_primitive(flag - 1, b) }
+   |                                                        ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:51:28
+  --> $DIR/only_used_in_recursion.rs:55:29
    |
-LL | fn not_primitive(a: usize, b: String) -> usize {
-   |                            ^ help: if this is intentional, prefix with an underscore: `_b`
+LL |     fn _method(flag: usize, a: usize) -> usize {
+   |                             ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:56:59
+   |
+LL |         if flag == 0 { 0 } else { Self::_method(flag - 1, a) }
+   |                                                           ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:68:33
+  --> $DIR/only_used_in_recursion.rs:59:22
    |
-LL |     fn method2(&self, a: usize, b: usize) -> usize {
-   |                                 ^ help: if this is intentional, prefix with an underscore: `_b`
+LL |     fn _method_self(&self, flag: usize, a: usize) -> usize {
+   |                      ^^^^
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:60:35
+   |
+LL |         if flag == 0 { 0 } else { self._method_self(flag - 1, a) }
+   |                                   ^^^^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:90:24
+  --> $DIR/only_used_in_recursion.rs:59:41
    |
-LL |     fn hello(a: usize, b: usize) -> usize {
-   |                        ^ help: if this is intentional, prefix with an underscore: `_b`
+LL |     fn _method_self(&self, flag: usize, a: usize) -> usize {
+   |                                         ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:60:63
+   |
+LL |         if flag == 0 { 0 } else { self._method_self(flag - 1, a) }
+   |                                                               ^
 
 error: parameter is only used in recursion
-  --> $DIR/only_used_in_recursion.rs:94:32
+  --> $DIR/only_used_in_recursion.rs:70:26
    |
-LL |     fn hello2(&self, a: usize, b: usize) -> usize {
-   |                                ^ help: if this is intentional, prefix with an underscore: `_b`
+LL |     fn method(flag: u32, a: usize) -> usize {
+   |                          ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:71:58
+   |
+LL |         if flag == 0 { 0 } else { Self::method(flag - 1, a) }
+   |                                                          ^
 
-error: aborting due to 13 previous errors
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion.rs:74:38
+   |
+LL |     fn method_self(&self, flag: u32, a: usize) -> usize {
+   |                                      ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:75:62
+   |
+LL |         if flag == 0 { 0 } else { self.method_self(flag - 1, a) }
+   |                                                              ^
+
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion.rs:100:26
+   |
+LL |     fn method(flag: u32, a: usize) -> usize {
+   |                          ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:101:58
+   |
+LL |         if flag == 0 { 0 } else { Self::method(flag - 1, a) }
+   |                                                          ^
+
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion.rs:104:38
+   |
+LL |     fn method_self(&self, flag: u32, a: usize) -> usize {
+   |                                      ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion.rs:105:62
+   |
+LL |         if flag == 0 { 0 } else { self.method_self(flag - 1, a) }
+   |                                                              ^
+
+error: aborting due to 16 previous errors
 
diff --git a/src/tools/clippy/tests/ui/only_used_in_recursion2.rs b/src/tools/clippy/tests/ui/only_used_in_recursion2.rs
new file mode 100644
index 000000000000..45dd0553f58a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/only_used_in_recursion2.rs
@@ -0,0 +1,91 @@
+#![warn(clippy::only_used_in_recursion)]
+
+fn _with_inner(flag: u32, a: u32, b: u32) -> usize {
+    fn inner(flag: u32, a: u32) -> u32 {
+        if flag == 0 { 0 } else { inner(flag, a) }
+    }
+
+    let x = inner(flag, a);
+    if flag == 0 { 0 } else { _with_inner(flag, a, b + x) }
+}
+
+fn _with_closure(a: Option<u32>, b: u32, f: impl Fn(u32, u32) -> Option<u32>) -> u32 {
+    if let Some(x) = a.and_then(|x| f(x, x)) {
+        _with_closure(Some(x), b, f)
+    } else {
+        0
+    }
+}
+
+// Issue #8560
+trait D {
+    fn foo(&mut self, arg: u32) -> u32;
+}
+
+mod m {
+    pub struct S(u32);
+    impl S {
+        pub fn foo(&mut self, arg: u32) -> u32 {
+            arg + self.0
+        }
+    }
+}
+
+impl D for m::S {
+    fn foo(&mut self, arg: u32) -> u32 {
+        self.foo(arg)
+    }
+}
+
+// Issue #8782
+fn only_let(x: u32) {
+    let y = 10u32;
+    let _z = x * y;
+}
+
+trait E<T: E<()>> {
+    fn method(flag: u32, a: usize) -> usize {
+        if flag == 0 {
+            0
+        } else {
+            <T as E<()>>::method(flag - 1, a)
+        }
+    }
+}
+
+impl E<()> for () {
+    fn method(flag: u32, a: usize) -> usize {
+        if flag == 0 { 0 } else { a }
+    }
+}
+
+fn overwritten_param(flag: u32, mut a: usize) -> usize {
+    if flag == 0 {
+        return 0;
+    } else if flag > 5 {
+        a += flag as usize;
+    } else {
+        a = 5;
+    }
+    overwritten_param(flag, a)
+}
+
+fn field_direct(flag: u32, mut a: (usize,)) -> usize {
+    if flag == 0 {
+        0
+    } else {
+        a.0 += 5;
+        field_direct(flag - 1, a)
+    }
+}
+
+fn field_deref(flag: u32, a: &mut Box<(usize,)>) -> usize {
+    if flag == 0 {
+        0
+    } else {
+        a.0 += 5;
+        field_deref(flag - 1, a)
+    }
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/only_used_in_recursion2.stderr b/src/tools/clippy/tests/ui/only_used_in_recursion2.stderr
new file mode 100644
index 000000000000..23f6ffd30c97
--- /dev/null
+++ b/src/tools/clippy/tests/ui/only_used_in_recursion2.stderr
@@ -0,0 +1,63 @@
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion2.rs:3:35
+   |
+LL | fn _with_inner(flag: u32, a: u32, b: u32) -> usize {
+   |                                   ^ help: if this is intentional, prefix it with an underscore: `_b`
+   |
+   = note: `-D clippy::only-used-in-recursion` implied by `-D warnings`
+note: parameter used here
+  --> $DIR/only_used_in_recursion2.rs:9:52
+   |
+LL |     if flag == 0 { 0 } else { _with_inner(flag, a, b + x) }
+   |                                                    ^
+
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion2.rs:4:25
+   |
+LL |     fn inner(flag: u32, a: u32) -> u32 {
+   |                         ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion2.rs:5:47
+   |
+LL |         if flag == 0 { 0 } else { inner(flag, a) }
+   |                                               ^
+
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion2.rs:12:34
+   |
+LL | fn _with_closure(a: Option<u32>, b: u32, f: impl Fn(u32, u32) -> Option<u32>) -> u32 {
+   |                                  ^ help: if this is intentional, prefix it with an underscore: `_b`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion2.rs:14:32
+   |
+LL |         _with_closure(Some(x), b, f)
+   |                                ^
+
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion2.rs:62:37
+   |
+LL | fn overwritten_param(flag: u32, mut a: usize) -> usize {
+   |                                     ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion2.rs:70:29
+   |
+LL |     overwritten_param(flag, a)
+   |                             ^
+
+error: parameter is only used in recursion
+  --> $DIR/only_used_in_recursion2.rs:73:32
+   |
+LL | fn field_direct(flag: u32, mut a: (usize,)) -> usize {
+   |                                ^ help: if this is intentional, prefix it with an underscore: `_a`
+   |
+note: parameter used here
+  --> $DIR/only_used_in_recursion2.rs:78:32
+   |
+LL |         field_direct(flag - 1, a)
+   |                                ^
+
+error: aborting due to 5 previous errors
+
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.fixed b/src/tools/clippy/tests/ui/option_if_let_else.fixed
index b6d5e106f057..f15ac551bb3c 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.fixed
+++ b/src/tools/clippy/tests/ui/option_if_let_else.fixed
@@ -179,4 +179,13 @@ fn main() {
 
     let _ = pattern_to_vec("hello world");
     let _ = complex_subpat();
+
+    // issue #8492
+    let _ = s.map_or(1, |string| string.len());
+    let _ = Some(10).map_or(5, |a| a + 1);
+
+    let res: Result<i32, i32> = Ok(5);
+    let _ = res.map_or(1, |a| a + 1);
+    let _ = res.map_or(1, |a| a + 1);
+    let _ = res.map_or(5, |a| a + 1);
 }
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.rs b/src/tools/clippy/tests/ui/option_if_let_else.rs
index 35bae1593435..9eeaea12d3bc 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.rs
+++ b/src/tools/clippy/tests/ui/option_if_let_else.rs
@@ -208,4 +208,25 @@ fn main() {
 
     let _ = pattern_to_vec("hello world");
     let _ = complex_subpat();
+
+    // issue #8492
+    let _ = match s {
+        Some(string) => string.len(),
+        None => 1,
+    };
+    let _ = match Some(10) {
+        Some(a) => a + 1,
+        None => 5,
+    };
+
+    let res: Result<i32, i32> = Ok(5);
+    let _ = match res {
+        Ok(a) => a + 1,
+        _ => 1,
+    };
+    let _ = match res {
+        Err(_) => 1,
+        Ok(a) => a + 1,
+    };
+    let _ = if let Ok(a) = res { a + 1 } else { 5 };
 }
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.stderr b/src/tools/clippy/tests/ui/option_if_let_else.stderr
index daba606004e1..a5dbf6e1f221 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.stderr
+++ b/src/tools/clippy/tests/ui/option_if_let_else.stderr
@@ -206,5 +206,51 @@ LL +         s.len() + x
 LL ~     });
    |
 
-error: aborting due to 15 previous errors
+error: use Option::map_or instead of an if let/else
+  --> $DIR/option_if_let_else.rs:213:13
+   |
+LL |       let _ = match s {
+   |  _____________^
+LL | |         Some(string) => string.len(),
+LL | |         None => 1,
+LL | |     };
+   | |_____^ help: try: `s.map_or(1, |string| string.len())`
+
+error: use Option::map_or instead of an if let/else
+  --> $DIR/option_if_let_else.rs:217:13
+   |
+LL |       let _ = match Some(10) {
+   |  _____________^
+LL | |         Some(a) => a + 1,
+LL | |         None => 5,
+LL | |     };
+   | |_____^ help: try: `Some(10).map_or(5, |a| a + 1)`
+
+error: use Option::map_or instead of an if let/else
+  --> $DIR/option_if_let_else.rs:223:13
+   |
+LL |       let _ = match res {
+   |  _____________^
+LL | |         Ok(a) => a + 1,
+LL | |         _ => 1,
+LL | |     };
+   | |_____^ help: try: `res.map_or(1, |a| a + 1)`
+
+error: use Option::map_or instead of an if let/else
+  --> $DIR/option_if_let_else.rs:227:13
+   |
+LL |       let _ = match res {
+   |  _____________^
+LL | |         Err(_) => 1,
+LL | |         Ok(a) => a + 1,
+LL | |     };
+   | |_____^ help: try: `res.map_or(1, |a| a + 1)`
+
+error: use Option::map_or instead of an if let/else
+  --> $DIR/option_if_let_else.rs:231:13
+   |
+LL |     let _ = if let Ok(a) = res { a + 1 } else { 5 };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `res.map_or(5, |a| a + 1)`
+
+error: aborting due to 20 previous errors
 
diff --git a/src/tools/clippy/tests/ui/or_fun_call.fixed b/src/tools/clippy/tests/ui/or_fun_call.fixed
index fdb08d953ff1..5991188ab637 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.fixed
+++ b/src/tools/clippy/tests/ui/or_fun_call.fixed
@@ -79,19 +79,19 @@ fn or_fun_call() {
     without_default.unwrap_or_else(Foo::new);
 
     let mut map = HashMap::<u64, String>::new();
-    map.entry(42).or_insert(String::new());
+    map.entry(42).or_default();
 
     let mut map_vec = HashMap::<u64, Vec<i32>>::new();
-    map_vec.entry(42).or_insert(vec![]);
+    map_vec.entry(42).or_default();
 
     let mut btree = BTreeMap::<u64, String>::new();
-    btree.entry(42).or_insert(String::new());
+    btree.entry(42).or_default();
 
     let mut btree_vec = BTreeMap::<u64, Vec<i32>>::new();
-    btree_vec.entry(42).or_insert(vec![]);
+    btree_vec.entry(42).or_default();
 
-    let stringy = Some(String::from(""));
-    let _ = stringy.unwrap_or_else(|| "".to_owned());
+    let stringy = Some(String::new());
+    let _ = stringy.unwrap_or_default();
 
     let opt = Some(1);
     let hello = "Hello";
diff --git a/src/tools/clippy/tests/ui/or_fun_call.rs b/src/tools/clippy/tests/ui/or_fun_call.rs
index 57ab5f03ee28..c353b41e4495 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.rs
+++ b/src/tools/clippy/tests/ui/or_fun_call.rs
@@ -90,8 +90,8 @@ fn or_fun_call() {
     let mut btree_vec = BTreeMap::<u64, Vec<i32>>::new();
     btree_vec.entry(42).or_insert(vec![]);
 
-    let stringy = Some(String::from(""));
-    let _ = stringy.unwrap_or("".to_owned());
+    let stringy = Some(String::new());
+    let _ = stringy.unwrap_or(String::new());
 
     let opt = Some(1);
     let hello = "Hello";
diff --git a/src/tools/clippy/tests/ui/or_fun_call.stderr b/src/tools/clippy/tests/ui/or_fun_call.stderr
index 4c5938ab88b9..e3dab4cb1477 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.stderr
+++ b/src/tools/clippy/tests/ui/or_fun_call.stderr
@@ -66,11 +66,35 @@ error: use of `unwrap_or` followed by a function call
 LL |     without_default.unwrap_or(Foo::new());
    |                     ^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(Foo::new)`
 
-error: use of `unwrap_or` followed by a function call
+error: use of `or_insert` followed by a call to `new`
+  --> $DIR/or_fun_call.rs:82:19
+   |
+LL |     map.entry(42).or_insert(String::new());
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_default()`
+
+error: use of `or_insert` followed by a call to `new`
+  --> $DIR/or_fun_call.rs:85:23
+   |
+LL |     map_vec.entry(42).or_insert(vec![]);
+   |                       ^^^^^^^^^^^^^^^^^ help: try this: `or_default()`
+
+error: use of `or_insert` followed by a call to `new`
+  --> $DIR/or_fun_call.rs:88:21
+   |
+LL |     btree.entry(42).or_insert(String::new());
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_default()`
+
+error: use of `or_insert` followed by a call to `new`
+  --> $DIR/or_fun_call.rs:91:25
+   |
+LL |     btree_vec.entry(42).or_insert(vec![]);
+   |                         ^^^^^^^^^^^^^^^^^ help: try this: `or_default()`
+
+error: use of `unwrap_or` followed by a call to `new`
   --> $DIR/or_fun_call.rs:94:21
    |
-LL |     let _ = stringy.unwrap_or("".to_owned());
-   |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "".to_owned())`
+LL |     let _ = stringy.unwrap_or(String::new());
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_default()`
 
 error: use of `unwrap_or` followed by a function call
   --> $DIR/or_fun_call.rs:102:21
@@ -132,5 +156,5 @@ error: use of `unwrap_or` followed by a call to `new`
 LL |         .unwrap_or(String::new());
    |          ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_default()`
 
-error: aborting due to 22 previous errors
+error: aborting due to 26 previous errors
 
diff --git a/src/tools/clippy/tests/ui/partialeq_to_none.fixed b/src/tools/clippy/tests/ui/partialeq_to_none.fixed
index f3e4c58d6949..4644ea8f51da 100644
--- a/src/tools/clippy/tests/ui/partialeq_to_none.fixed
+++ b/src/tools/clippy/tests/ui/partialeq_to_none.fixed
@@ -26,6 +26,18 @@ fn optref() -> &'static &'static Option<()> {
     &&None
 }
 
+pub fn macro_expansion() {
+    macro_rules! foo {
+        () => {
+            None::<()>
+        };
+    }
+
+    let _ = foobar() == foo!();
+    let _ = foo!() == foobar();
+    let _ = foo!() == foo!();
+}
+
 fn main() {
     let x = Some(0);
 
diff --git a/src/tools/clippy/tests/ui/partialeq_to_none.rs b/src/tools/clippy/tests/ui/partialeq_to_none.rs
index 767b2a38bcc1..61011b3a8c55 100644
--- a/src/tools/clippy/tests/ui/partialeq_to_none.rs
+++ b/src/tools/clippy/tests/ui/partialeq_to_none.rs
@@ -26,6 +26,18 @@ fn optref() -> &'static &'static Option<()> {
     &&None
 }
 
+pub fn macro_expansion() {
+    macro_rules! foo {
+        () => {
+            None::<()>
+        };
+    }
+
+    let _ = foobar() == foo!();
+    let _ = foo!() == foobar();
+    let _ = foo!() == foo!();
+}
+
 fn main() {
     let x = Some(0);
 
diff --git a/src/tools/clippy/tests/ui/partialeq_to_none.stderr b/src/tools/clippy/tests/ui/partialeq_to_none.stderr
index de15a9f7baaf..d06ab7aee558 100644
--- a/src/tools/clippy/tests/ui/partialeq_to_none.stderr
+++ b/src/tools/clippy/tests/ui/partialeq_to_none.stderr
@@ -7,55 +7,55 @@ LL |     if f != None { "yay" } else { "nay" }
    = note: `-D clippy::partialeq-to-none` implied by `-D warnings`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:32:13
+  --> $DIR/partialeq_to_none.rs:44:13
    |
 LL |     let _ = x == None;
    |             ^^^^^^^^^ help: use `Option::is_none()` instead: `x.is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:33:13
+  --> $DIR/partialeq_to_none.rs:45:13
    |
 LL |     let _ = x != None;
    |             ^^^^^^^^^ help: use `Option::is_some()` instead: `x.is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:34:13
+  --> $DIR/partialeq_to_none.rs:46:13
    |
 LL |     let _ = None == x;
    |             ^^^^^^^^^ help: use `Option::is_none()` instead: `x.is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:35:13
+  --> $DIR/partialeq_to_none.rs:47:13
    |
 LL |     let _ = None != x;
    |             ^^^^^^^^^ help: use `Option::is_some()` instead: `x.is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:37:8
+  --> $DIR/partialeq_to_none.rs:49:8
    |
 LL |     if foobar() == None {}
    |        ^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `foobar().is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:39:8
+  --> $DIR/partialeq_to_none.rs:51:8
    |
 LL |     if bar().ok() != None {}
    |        ^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `bar().ok().is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:41:13
+  --> $DIR/partialeq_to_none.rs:53:13
    |
 LL |     let _ = Some(1 + 2) != None;
    |             ^^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `Some(1 + 2).is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:43:13
+  --> $DIR/partialeq_to_none.rs:55:13
    |
 LL |     let _ = { Some(0) } == None;
    |             ^^^^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `{ Some(0) }.is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:45:13
+  --> $DIR/partialeq_to_none.rs:57:13
    |
 LL |       let _ = {
    |  _____________^
@@ -77,31 +77,31 @@ LL ~     }.is_some();
    |
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:55:13
+  --> $DIR/partialeq_to_none.rs:67:13
    |
 LL |     let _ = optref() == &&None;
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `optref().is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:56:13
+  --> $DIR/partialeq_to_none.rs:68:13
    |
 LL |     let _ = &&None != optref();
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `optref().is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:57:13
+  --> $DIR/partialeq_to_none.rs:69:13
    |
 LL |     let _ = **optref() == None;
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_none()` instead: `optref().is_none()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:58:13
+  --> $DIR/partialeq_to_none.rs:70:13
    |
 LL |     let _ = &None != *optref();
    |             ^^^^^^^^^^^^^^^^^^ help: use `Option::is_some()` instead: `optref().is_some()`
 
 error: binary comparison to literal `Option::None`
-  --> $DIR/partialeq_to_none.rs:61:13
+  --> $DIR/partialeq_to_none.rs:73:13
    |
 LL |     let _ = None != *x;
    |             ^^^^^^^^^^ help: use `Option::is_some()` instead: `(*x).is_some()`
diff --git a/src/tools/clippy/tests/ui/print_literal.rs b/src/tools/clippy/tests/ui/print_literal.rs
index 8665a3bb28ae..3f6639c14585 100644
--- a/src/tools/clippy/tests/ui/print_literal.rs
+++ b/src/tools/clippy/tests/ui/print_literal.rs
@@ -20,11 +20,13 @@ fn main() {
     println!("{} of {:b} people know binary, the other half doesn't", 1, 2);
     println!("10 / 4 is {}", 2.5);
     println!("2 + 1 = {}", 3);
+    println!("From expansion {}", stringify!(not a string literal));
 
     // these should throw warnings
     print!("Hello {}", "world");
     println!("Hello {} {}", world, "world");
     println!("Hello {}", "world");
+    println!("{} {:.4}", "a literal", 5);
 
     // positional args don't change the fact
     // that we're using a literal -- this should
diff --git a/src/tools/clippy/tests/ui/print_literal.stderr b/src/tools/clippy/tests/ui/print_literal.stderr
index 72aae0756033..23e6dbc3e341 100644
--- a/src/tools/clippy/tests/ui/print_literal.stderr
+++ b/src/tools/clippy/tests/ui/print_literal.stderr
@@ -1,5 +1,5 @@
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:25:24
+  --> $DIR/print_literal.rs:26:24
    |
 LL |     print!("Hello {}", "world");
    |                        ^^^^^^^
@@ -12,7 +12,7 @@ LL +     print!("Hello world");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:26:36
+  --> $DIR/print_literal.rs:27:36
    |
 LL |     println!("Hello {} {}", world, "world");
    |                                    ^^^^^^^
@@ -24,7 +24,7 @@ LL +     println!("Hello {} world", world);
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:27:26
+  --> $DIR/print_literal.rs:28:26
    |
 LL |     println!("Hello {}", "world");
    |                          ^^^^^^^
@@ -36,7 +36,19 @@ LL +     println!("Hello world");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:32:25
+  --> $DIR/print_literal.rs:29:26
+   |
+LL |     println!("{} {:.4}", "a literal", 5);
+   |                          ^^^^^^^^^^^
+   |
+help: try this
+   |
+LL -     println!("{} {:.4}", "a literal", 5);
+LL +     println!("a literal {:.4}", 5);
+   |
+
+error: literal with an empty format string
+  --> $DIR/print_literal.rs:34:25
    |
 LL |     println!("{0} {1}", "hello", "world");
    |                         ^^^^^^^
@@ -48,7 +60,7 @@ LL +     println!("hello {1}", "world");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:32:34
+  --> $DIR/print_literal.rs:34:34
    |
 LL |     println!("{0} {1}", "hello", "world");
    |                                  ^^^^^^^
@@ -60,19 +72,7 @@ LL +     println!("{0} world", "hello");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:33:25
-   |
-LL |     println!("{1} {0}", "hello", "world");
-   |                         ^^^^^^^
-   |
-help: try this
-   |
-LL -     println!("{1} {0}", "hello", "world");
-LL +     println!("{1} hello", "world");
-   |
-
-error: literal with an empty format string
-  --> $DIR/print_literal.rs:33:34
+  --> $DIR/print_literal.rs:35:34
    |
 LL |     println!("{1} {0}", "hello", "world");
    |                                  ^^^^^^^
@@ -84,10 +84,22 @@ LL +     println!("world {0}", "hello");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:36:29
+  --> $DIR/print_literal.rs:35:25
+   |
+LL |     println!("{1} {0}", "hello", "world");
+   |                         ^^^^^^^
+   |
+help: try this
+   |
+LL -     println!("{1} {0}", "hello", "world");
+LL +     println!("{1} hello", "world");
+   |
+
+error: literal with an empty format string
+  --> $DIR/print_literal.rs:38:35
    |
 LL |     println!("{foo} {bar}", foo = "hello", bar = "world");
-   |                             ^^^^^^^^^^^^^
+   |                                   ^^^^^^^
    |
 help: try this
    |
@@ -96,10 +108,10 @@ LL +     println!("hello {bar}", bar = "world");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:36:44
+  --> $DIR/print_literal.rs:38:50
    |
 LL |     println!("{foo} {bar}", foo = "hello", bar = "world");
-   |                                            ^^^^^^^^^^^^^
+   |                                                  ^^^^^^^
    |
 help: try this
    |
@@ -108,22 +120,10 @@ LL +     println!("{foo} world", foo = "hello");
    |
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:37:29
+  --> $DIR/print_literal.rs:39:50
    |
 LL |     println!("{bar} {foo}", foo = "hello", bar = "world");
-   |                             ^^^^^^^^^^^^^
-   |
-help: try this
-   |
-LL -     println!("{bar} {foo}", foo = "hello", bar = "world");
-LL +     println!("{bar} hello", bar = "world");
-   |
-
-error: literal with an empty format string
-  --> $DIR/print_literal.rs:37:44
-   |
-LL |     println!("{bar} {foo}", foo = "hello", bar = "world");
-   |                                            ^^^^^^^^^^^^^
+   |                                                  ^^^^^^^
    |
 help: try this
    |
@@ -131,5 +131,17 @@ LL -     println!("{bar} {foo}", foo = "hello", bar = "world");
 LL +     println!("world {foo}", foo = "hello");
    |
 
-error: aborting due to 11 previous errors
+error: literal with an empty format string
+  --> $DIR/print_literal.rs:39:35
+   |
+LL |     println!("{bar} {foo}", foo = "hello", bar = "world");
+   |                                   ^^^^^^^
+   |
+help: try this
+   |
+LL -     println!("{bar} {foo}", foo = "hello", bar = "world");
+LL +     println!("{bar} hello", bar = "world");
+   |
+
+error: aborting due to 12 previous errors
 
diff --git a/src/tools/clippy/tests/ui/print_with_newline.rs b/src/tools/clippy/tests/ui/print_with_newline.rs
index a43a1fc4f524..b8c29d207ada 100644
--- a/src/tools/clippy/tests/ui/print_with_newline.rs
+++ b/src/tools/clippy/tests/ui/print_with_newline.rs
@@ -48,5 +48,13 @@ fn main() {
     print!("\r\n");
     print!("foo\r\n");
     print!("\\r\n"); //~ ERROR
-    print!("foo\rbar\n") // ~ ERROR
+    print!("foo\rbar\n");
+
+    // Ignore expanded format strings
+    macro_rules! newline {
+        () => {
+            "\n"
+        };
+    }
+    print!(newline!());
 }
diff --git a/src/tools/clippy/tests/ui/print_with_newline.stderr b/src/tools/clippy/tests/ui/print_with_newline.stderr
index edbaa1cdf979..b9f5675faec7 100644
--- a/src/tools/clippy/tests/ui/print_with_newline.stderr
+++ b/src/tools/clippy/tests/ui/print_with_newline.stderr
@@ -83,7 +83,7 @@ LL | |     );
 help: use `println!` instead
    |
 LL ~     println!(
-LL ~         ""
+LL ~         
    |
 
 error: using `print!()` with a format string that ends in a single newline
@@ -98,7 +98,7 @@ LL | |     );
 help: use `println!` instead
    |
 LL ~     println!(
-LL ~         r""
+LL ~         
    |
 
 error: using `print!()` with a format string that ends in a single newline
@@ -113,17 +113,5 @@ LL -     print!("/r/n"); //~ ERROR
 LL +     println!("/r"); //~ ERROR
    |
 
-error: using `print!()` with a format string that ends in a single newline
-  --> $DIR/print_with_newline.rs:51:5
-   |
-LL |     print!("foo/rbar/n") // ~ ERROR
-   |     ^^^^^^^^^^^^^^^^^^^^
-   |
-help: use `println!` instead
-   |
-LL -     print!("foo/rbar/n") // ~ ERROR
-LL +     println!("foo/rbar") // ~ ERROR
-   |
-
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
diff --git a/src/tools/clippy/tests/ui/println_empty_string.stderr b/src/tools/clippy/tests/ui/println_empty_string.stderr
index 17fe4ea74790..3cc8bb947bd3 100644
--- a/src/tools/clippy/tests/ui/println_empty_string.stderr
+++ b/src/tools/clippy/tests/ui/println_empty_string.stderr
@@ -1,28 +1,36 @@
-error: using `println!("")`
+error: empty string literal in `println!`
   --> $DIR/println_empty_string.rs:6:5
    |
 LL |     println!("");
-   |     ^^^^^^^^^^^^ help: replace it with: `println!()`
+   |     ^^^^^^^^^--^
+   |              |
+   |              help: remove the empty string
    |
    = note: `-D clippy::println-empty-string` implied by `-D warnings`
 
-error: using `println!("")`
+error: empty string literal in `println!`
   --> $DIR/println_empty_string.rs:9:14
    |
 LL |         _ => println!(""),
-   |              ^^^^^^^^^^^^ help: replace it with: `println!()`
+   |              ^^^^^^^^^--^
+   |                       |
+   |                       help: remove the empty string
 
-error: using `eprintln!("")`
+error: empty string literal in `eprintln!`
   --> $DIR/println_empty_string.rs:13:5
    |
 LL |     eprintln!("");
-   |     ^^^^^^^^^^^^^ help: replace it with: `eprintln!()`
+   |     ^^^^^^^^^^--^
+   |               |
+   |               help: remove the empty string
 
-error: using `eprintln!("")`
+error: empty string literal in `eprintln!`
   --> $DIR/println_empty_string.rs:16:14
    |
 LL |         _ => eprintln!(""),
-   |              ^^^^^^^^^^^^^ help: replace it with: `eprintln!()`
+   |              ^^^^^^^^^^--^
+   |                        |
+   |                        help: remove the empty string
 
 error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/question_mark.fixed b/src/tools/clippy/tests/ui/question_mark.fixed
index c4c9c8214333..57f23bd1916f 100644
--- a/src/tools/clippy/tests/ui/question_mark.fixed
+++ b/src/tools/clippy/tests/ui/question_mark.fixed
@@ -207,4 +207,19 @@ fn option_map() -> Option<bool> {
     }
 }
 
+pub struct PatternedError {
+    flag: bool,
+}
+
+// No warning
+fn pattern() -> Result<(), PatternedError> {
+    let res = Ok(());
+
+    if let Err(err @ PatternedError { flag: true }) = res {
+        return Err(err);
+    }
+
+    res
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/question_mark.rs b/src/tools/clippy/tests/ui/question_mark.rs
index cdbc7b1606f8..436f027c215d 100644
--- a/src/tools/clippy/tests/ui/question_mark.rs
+++ b/src/tools/clippy/tests/ui/question_mark.rs
@@ -243,4 +243,19 @@ fn option_map() -> Option<bool> {
     }
 }
 
+pub struct PatternedError {
+    flag: bool,
+}
+
+// No warning
+fn pattern() -> Result<(), PatternedError> {
+    let res = Ok(());
+
+    if let Err(err @ PatternedError { flag: true }) = res {
+        return Err(err);
+    }
+
+    res
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/range_plus_minus_one.fixed b/src/tools/clippy/tests/ui/range_plus_minus_one.fixed
index 40d7791df281..a16a3e54d45e 100644
--- a/src/tools/clippy/tests/ui/range_plus_minus_one.fixed
+++ b/src/tools/clippy/tests/ui/range_plus_minus_one.fixed
@@ -6,6 +6,22 @@ fn f() -> usize {
     42
 }
 
+macro_rules! macro_plus_one {
+    ($m: literal) => {
+        for i in 0..$m + 1 {
+            println!("{}", i);
+        }
+    };
+}
+
+macro_rules! macro_minus_one {
+    ($m: literal) => {
+        for i in 0..=$m - 1 {
+            println!("{}", i);
+        }
+    };
+}
+
 #[warn(clippy::range_plus_one)]
 #[warn(clippy::range_minus_one)]
 fn main() {
@@ -39,4 +55,7 @@ fn main() {
 
     let mut vec: Vec<()> = std::vec::Vec::new();
     vec.drain(..);
+
+    macro_plus_one!(5);
+    macro_minus_one!(5);
 }
diff --git a/src/tools/clippy/tests/ui/range_plus_minus_one.rs b/src/tools/clippy/tests/ui/range_plus_minus_one.rs
index a8ddd9b5f751..bd6cb4d21be5 100644
--- a/src/tools/clippy/tests/ui/range_plus_minus_one.rs
+++ b/src/tools/clippy/tests/ui/range_plus_minus_one.rs
@@ -6,6 +6,22 @@ fn f() -> usize {
     42
 }
 
+macro_rules! macro_plus_one {
+    ($m: literal) => {
+        for i in 0..$m + 1 {
+            println!("{}", i);
+        }
+    };
+}
+
+macro_rules! macro_minus_one {
+    ($m: literal) => {
+        for i in 0..=$m - 1 {
+            println!("{}", i);
+        }
+    };
+}
+
 #[warn(clippy::range_plus_one)]
 #[warn(clippy::range_minus_one)]
 fn main() {
@@ -39,4 +55,7 @@ fn main() {
 
     let mut vec: Vec<()> = std::vec::Vec::new();
     vec.drain(..);
+
+    macro_plus_one!(5);
+    macro_minus_one!(5);
 }
diff --git a/src/tools/clippy/tests/ui/range_plus_minus_one.stderr b/src/tools/clippy/tests/ui/range_plus_minus_one.stderr
index fb4f1658597a..0223696243b2 100644
--- a/src/tools/clippy/tests/ui/range_plus_minus_one.stderr
+++ b/src/tools/clippy/tests/ui/range_plus_minus_one.stderr
@@ -1,5 +1,5 @@
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:15:14
+  --> $DIR/range_plus_minus_one.rs:31:14
    |
 LL |     for _ in 0..3 + 1 {}
    |              ^^^^^^^^ help: use: `0..=3`
@@ -7,25 +7,25 @@ LL |     for _ in 0..3 + 1 {}
    = note: `-D clippy::range-plus-one` implied by `-D warnings`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:18:14
+  --> $DIR/range_plus_minus_one.rs:34:14
    |
 LL |     for _ in 0..1 + 5 {}
    |              ^^^^^^^^ help: use: `0..=5`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:21:14
+  --> $DIR/range_plus_minus_one.rs:37:14
    |
 LL |     for _ in 1..1 + 1 {}
    |              ^^^^^^^^ help: use: `1..=1`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:27:14
+  --> $DIR/range_plus_minus_one.rs:43:14
    |
 LL |     for _ in 0..(1 + f()) {}
    |              ^^^^^^^^^^^^ help: use: `0..=f()`
 
 error: an exclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:31:13
+  --> $DIR/range_plus_minus_one.rs:47:13
    |
 LL |     let _ = ..=11 - 1;
    |             ^^^^^^^^^ help: use: `..11`
@@ -33,25 +33,25 @@ LL |     let _ = ..=11 - 1;
    = note: `-D clippy::range-minus-one` implied by `-D warnings`
 
 error: an exclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:32:13
+  --> $DIR/range_plus_minus_one.rs:48:13
    |
 LL |     let _ = ..=(11 - 1);
    |             ^^^^^^^^^^^ help: use: `..11`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:33:13
+  --> $DIR/range_plus_minus_one.rs:49:13
    |
 LL |     let _ = (1..11 + 1);
    |             ^^^^^^^^^^^ help: use: `(1..=11)`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:34:13
+  --> $DIR/range_plus_minus_one.rs:50:13
    |
 LL |     let _ = (f() + 1)..(f() + 1);
    |             ^^^^^^^^^^^^^^^^^^^^ help: use: `((f() + 1)..=f())`
 
 error: an inclusive range would be more readable
-  --> $DIR/range_plus_minus_one.rs:38:14
+  --> $DIR/range_plus_minus_one.rs:54:14
    |
 LL |     for _ in 1..ONE + ONE {}
    |              ^^^^^^^^^^^^ help: use: `1..=ONE`
diff --git a/src/tools/clippy/tests/ui/regex.rs b/src/tools/clippy/tests/ui/regex.rs
index f7f3b195ccc1..f0e1a8128d7c 100644
--- a/src/tools/clippy/tests/ui/regex.rs
+++ b/src/tools/clippy/tests/ui/regex.rs
@@ -1,4 +1,4 @@
-#![allow(unused)]
+#![allow(unused, clippy::needless_borrow)]
 #![warn(clippy::invalid_regex, clippy::trivial_regex)]
 
 extern crate regex;
diff --git a/src/tools/clippy/tests/ui/rename.fixed b/src/tools/clippy/tests/ui/rename.fixed
index 9cbad2269a09..a6e7bdba77c6 100644
--- a/src/tools/clippy/tests/ui/rename.fixed
+++ b/src/tools/clippy/tests/ui/rename.fixed
@@ -32,6 +32,7 @@
 #![allow(invalid_value)]
 #![allow(enum_intrinsics_non_enums)]
 #![allow(non_fmt_panics)]
+#![allow(named_arguments_used_positionally)]
 #![allow(temporary_cstring_as_ptr)]
 #![allow(unknown_lints)]
 #![allow(unused_labels)]
@@ -69,6 +70,7 @@
 #![warn(invalid_value)]
 #![warn(enum_intrinsics_non_enums)]
 #![warn(non_fmt_panics)]
+#![warn(named_arguments_used_positionally)]
 #![warn(temporary_cstring_as_ptr)]
 #![warn(unknown_lints)]
 #![warn(unused_labels)]
diff --git a/src/tools/clippy/tests/ui/rename.rs b/src/tools/clippy/tests/ui/rename.rs
index 9153c0dab029..e8f57597d02b 100644
--- a/src/tools/clippy/tests/ui/rename.rs
+++ b/src/tools/clippy/tests/ui/rename.rs
@@ -32,6 +32,7 @@
 #![allow(invalid_value)]
 #![allow(enum_intrinsics_non_enums)]
 #![allow(non_fmt_panics)]
+#![allow(named_arguments_used_positionally)]
 #![allow(temporary_cstring_as_ptr)]
 #![allow(unknown_lints)]
 #![allow(unused_labels)]
@@ -69,6 +70,7 @@
 #![warn(clippy::invalid_ref)]
 #![warn(clippy::mem_discriminant_non_enum)]
 #![warn(clippy::panic_params)]
+#![warn(clippy::positional_named_format_parameters)]
 #![warn(clippy::temporary_cstring_as_ptr)]
 #![warn(clippy::unknown_clippy_lints)]
 #![warn(clippy::unused_label)]
diff --git a/src/tools/clippy/tests/ui/rename.stderr b/src/tools/clippy/tests/ui/rename.stderr
index 9c03ea914bb6..31865a7f66d6 100644
--- a/src/tools/clippy/tests/ui/rename.stderr
+++ b/src/tools/clippy/tests/ui/rename.stderr
@@ -1,5 +1,5 @@
 error: lint `clippy::blacklisted_name` has been renamed to `clippy::disallowed_names`
-  --> $DIR/rename.rs:38:9
+  --> $DIR/rename.rs:39:9
    |
 LL | #![warn(clippy::blacklisted_name)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_names`
@@ -7,220 +7,226 @@ LL | #![warn(clippy::blacklisted_name)]
    = note: `-D renamed-and-removed-lints` implied by `-D warnings`
 
 error: lint `clippy::block_in_if_condition_expr` has been renamed to `clippy::blocks_in_if_conditions`
-  --> $DIR/rename.rs:39:9
+  --> $DIR/rename.rs:40:9
    |
 LL | #![warn(clippy::block_in_if_condition_expr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_if_conditions`
 
 error: lint `clippy::block_in_if_condition_stmt` has been renamed to `clippy::blocks_in_if_conditions`
-  --> $DIR/rename.rs:40:9
+  --> $DIR/rename.rs:41:9
    |
 LL | #![warn(clippy::block_in_if_condition_stmt)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_if_conditions`
 
 error: lint `clippy::box_vec` has been renamed to `clippy::box_collection`
-  --> $DIR/rename.rs:41:9
+  --> $DIR/rename.rs:42:9
    |
 LL | #![warn(clippy::box_vec)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::box_collection`
 
 error: lint `clippy::const_static_lifetime` has been renamed to `clippy::redundant_static_lifetimes`
-  --> $DIR/rename.rs:42:9
+  --> $DIR/rename.rs:43:9
    |
 LL | #![warn(clippy::const_static_lifetime)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::redundant_static_lifetimes`
 
 error: lint `clippy::cyclomatic_complexity` has been renamed to `clippy::cognitive_complexity`
-  --> $DIR/rename.rs:43:9
+  --> $DIR/rename.rs:44:9
    |
 LL | #![warn(clippy::cyclomatic_complexity)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::cognitive_complexity`
 
 error: lint `clippy::disallowed_method` has been renamed to `clippy::disallowed_methods`
-  --> $DIR/rename.rs:44:9
+  --> $DIR/rename.rs:45:9
    |
 LL | #![warn(clippy::disallowed_method)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_methods`
 
 error: lint `clippy::disallowed_type` has been renamed to `clippy::disallowed_types`
-  --> $DIR/rename.rs:45:9
+  --> $DIR/rename.rs:46:9
    |
 LL | #![warn(clippy::disallowed_type)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_types`
 
 error: lint `clippy::eval_order_dependence` has been renamed to `clippy::mixed_read_write_in_expression`
-  --> $DIR/rename.rs:46:9
+  --> $DIR/rename.rs:47:9
    |
 LL | #![warn(clippy::eval_order_dependence)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::mixed_read_write_in_expression`
 
 error: lint `clippy::for_loop_over_option` has been renamed to `clippy::for_loops_over_fallibles`
-  --> $DIR/rename.rs:47:9
+  --> $DIR/rename.rs:48:9
    |
 LL | #![warn(clippy::for_loop_over_option)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::for_loops_over_fallibles`
 
 error: lint `clippy::for_loop_over_result` has been renamed to `clippy::for_loops_over_fallibles`
-  --> $DIR/rename.rs:48:9
+  --> $DIR/rename.rs:49:9
    |
 LL | #![warn(clippy::for_loop_over_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::for_loops_over_fallibles`
 
 error: lint `clippy::identity_conversion` has been renamed to `clippy::useless_conversion`
-  --> $DIR/rename.rs:49:9
+  --> $DIR/rename.rs:50:9
    |
 LL | #![warn(clippy::identity_conversion)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::useless_conversion`
 
 error: lint `clippy::if_let_some_result` has been renamed to `clippy::match_result_ok`
-  --> $DIR/rename.rs:50:9
+  --> $DIR/rename.rs:51:9
    |
 LL | #![warn(clippy::if_let_some_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::match_result_ok`
 
 error: lint `clippy::logic_bug` has been renamed to `clippy::overly_complex_bool_expr`
-  --> $DIR/rename.rs:51:9
+  --> $DIR/rename.rs:52:9
    |
 LL | #![warn(clippy::logic_bug)]
    |         ^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::overly_complex_bool_expr`
 
 error: lint `clippy::new_without_default_derive` has been renamed to `clippy::new_without_default`
-  --> $DIR/rename.rs:52:9
+  --> $DIR/rename.rs:53:9
    |
 LL | #![warn(clippy::new_without_default_derive)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::new_without_default`
 
 error: lint `clippy::option_and_then_some` has been renamed to `clippy::bind_instead_of_map`
-  --> $DIR/rename.rs:53:9
+  --> $DIR/rename.rs:54:9
    |
 LL | #![warn(clippy::option_and_then_some)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::bind_instead_of_map`
 
 error: lint `clippy::option_expect_used` has been renamed to `clippy::expect_used`
-  --> $DIR/rename.rs:54:9
+  --> $DIR/rename.rs:55:9
    |
 LL | #![warn(clippy::option_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::option_map_unwrap_or` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:55:9
+  --> $DIR/rename.rs:56:9
    |
 LL | #![warn(clippy::option_map_unwrap_or)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:56:9
+  --> $DIR/rename.rs:57:9
    |
 LL | #![warn(clippy::option_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> $DIR/rename.rs:57:9
+  --> $DIR/rename.rs:58:9
    |
 LL | #![warn(clippy::option_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::ref_in_deref` has been renamed to `clippy::needless_borrow`
-  --> $DIR/rename.rs:58:9
+  --> $DIR/rename.rs:59:9
    |
 LL | #![warn(clippy::ref_in_deref)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::needless_borrow`
 
 error: lint `clippy::result_expect_used` has been renamed to `clippy::expect_used`
-  --> $DIR/rename.rs:59:9
+  --> $DIR/rename.rs:60:9
    |
 LL | #![warn(clippy::result_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::result_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:60:9
+  --> $DIR/rename.rs:61:9
    |
 LL | #![warn(clippy::result_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::result_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> $DIR/rename.rs:61:9
+  --> $DIR/rename.rs:62:9
    |
 LL | #![warn(clippy::result_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::single_char_push_str` has been renamed to `clippy::single_char_add_str`
-  --> $DIR/rename.rs:62:9
+  --> $DIR/rename.rs:63:9
    |
 LL | #![warn(clippy::single_char_push_str)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::single_char_add_str`
 
 error: lint `clippy::stutter` has been renamed to `clippy::module_name_repetitions`
-  --> $DIR/rename.rs:63:9
+  --> $DIR/rename.rs:64:9
    |
 LL | #![warn(clippy::stutter)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::module_name_repetitions`
 
 error: lint `clippy::to_string_in_display` has been renamed to `clippy::recursive_format_impl`
-  --> $DIR/rename.rs:64:9
+  --> $DIR/rename.rs:65:9
    |
 LL | #![warn(clippy::to_string_in_display)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::recursive_format_impl`
 
 error: lint `clippy::zero_width_space` has been renamed to `clippy::invisible_characters`
-  --> $DIR/rename.rs:65:9
+  --> $DIR/rename.rs:66:9
    |
 LL | #![warn(clippy::zero_width_space)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::invisible_characters`
 
 error: lint `clippy::drop_bounds` has been renamed to `drop_bounds`
-  --> $DIR/rename.rs:66:9
+  --> $DIR/rename.rs:67:9
    |
 LL | #![warn(clippy::drop_bounds)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `drop_bounds`
 
 error: lint `clippy::into_iter_on_array` has been renamed to `array_into_iter`
-  --> $DIR/rename.rs:67:9
+  --> $DIR/rename.rs:68:9
    |
 LL | #![warn(clippy::into_iter_on_array)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `array_into_iter`
 
 error: lint `clippy::invalid_atomic_ordering` has been renamed to `invalid_atomic_ordering`
-  --> $DIR/rename.rs:68:9
+  --> $DIR/rename.rs:69:9
    |
 LL | #![warn(clippy::invalid_atomic_ordering)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_atomic_ordering`
 
 error: lint `clippy::invalid_ref` has been renamed to `invalid_value`
-  --> $DIR/rename.rs:69:9
+  --> $DIR/rename.rs:70:9
    |
 LL | #![warn(clippy::invalid_ref)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_value`
 
 error: lint `clippy::mem_discriminant_non_enum` has been renamed to `enum_intrinsics_non_enums`
-  --> $DIR/rename.rs:70:9
+  --> $DIR/rename.rs:71:9
    |
 LL | #![warn(clippy::mem_discriminant_non_enum)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `enum_intrinsics_non_enums`
 
 error: lint `clippy::panic_params` has been renamed to `non_fmt_panics`
-  --> $DIR/rename.rs:71:9
+  --> $DIR/rename.rs:72:9
    |
 LL | #![warn(clippy::panic_params)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `non_fmt_panics`
 
+error: lint `clippy::positional_named_format_parameters` has been renamed to `named_arguments_used_positionally`
+  --> $DIR/rename.rs:73:9
+   |
+LL | #![warn(clippy::positional_named_format_parameters)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `named_arguments_used_positionally`
+
 error: lint `clippy::temporary_cstring_as_ptr` has been renamed to `temporary_cstring_as_ptr`
-  --> $DIR/rename.rs:72:9
+  --> $DIR/rename.rs:74:9
    |
 LL | #![warn(clippy::temporary_cstring_as_ptr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `temporary_cstring_as_ptr`
 
 error: lint `clippy::unknown_clippy_lints` has been renamed to `unknown_lints`
-  --> $DIR/rename.rs:73:9
+  --> $DIR/rename.rs:75:9
    |
 LL | #![warn(clippy::unknown_clippy_lints)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unknown_lints`
 
 error: lint `clippy::unused_label` has been renamed to `unused_labels`
-  --> $DIR/rename.rs:74:9
+  --> $DIR/rename.rs:76:9
    |
 LL | #![warn(clippy::unused_label)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unused_labels`
 
-error: aborting due to 37 previous errors
+error: aborting due to 38 previous errors
 
diff --git a/src/tools/clippy/tests/ui/result_large_err.rs b/src/tools/clippy/tests/ui/result_large_err.rs
new file mode 100644
index 000000000000..f7df3b856550
--- /dev/null
+++ b/src/tools/clippy/tests/ui/result_large_err.rs
@@ -0,0 +1,99 @@
+#![warn(clippy::result_large_err)]
+#![allow(clippy::large_enum_variant)]
+
+pub fn small_err() -> Result<(), u128> {
+    Ok(())
+}
+
+pub fn large_err() -> Result<(), [u8; 512]> {
+    Ok(())
+}
+
+pub struct FullyDefinedLargeError {
+    _foo: u128,
+    _bar: [u8; 100],
+    _foobar: [u8; 120],
+}
+
+impl FullyDefinedLargeError {
+    pub fn ret() -> Result<(), Self> {
+        Ok(())
+    }
+}
+
+pub fn struct_error() -> Result<(), FullyDefinedLargeError> {
+    Ok(())
+}
+
+type Fdlr<T> = std::result::Result<T, FullyDefinedLargeError>;
+pub fn large_err_via_type_alias<T>(x: T) -> Fdlr<T> {
+    Ok(x)
+}
+
+pub fn param_small_error<R>() -> Result<(), (R, u128)> {
+    Ok(())
+}
+
+pub fn param_large_error<R>() -> Result<(), (u128, R, FullyDefinedLargeError)> {
+    Ok(())
+}
+
+pub enum LargeErrorVariants<T> {
+    _Small(u8),
+    _Omg([u8; 512]),
+    _Param(T),
+}
+
+impl LargeErrorVariants<()> {
+    pub fn large_enum_error() -> Result<(), Self> {
+        Ok(())
+    }
+}
+
+trait TraitForcesLargeError {
+    fn large_error() -> Result<(), [u8; 512]> {
+        Ok(())
+    }
+}
+
+struct TraitImpl;
+
+impl TraitForcesLargeError for TraitImpl {
+    // Should not lint
+    fn large_error() -> Result<(), [u8; 512]> {
+        Ok(())
+    }
+}
+
+pub union FullyDefinedUnionError {
+    _maybe: u8,
+    _or_even: [[u8; 16]; 32],
+}
+
+pub fn large_union_err() -> Result<(), FullyDefinedUnionError> {
+    Ok(())
+}
+
+pub union UnionError<T: Copy> {
+    _maybe: T,
+    _or_perhaps_even: (T, [u8; 512]),
+}
+
+pub fn param_large_union<T: Copy>() -> Result<(), UnionError<T>> {
+    Ok(())
+}
+
+pub struct ArrayError<T, U> {
+    _large_array: [T; 32],
+    _other_stuff: U,
+}
+
+pub fn array_error_subst<U>() -> Result<(), ArrayError<i32, U>> {
+    Ok(())
+}
+
+pub fn array_error<T, U>() -> Result<(), ArrayError<(i32, T), U>> {
+    Ok(())
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/result_large_err.stderr b/src/tools/clippy/tests/ui/result_large_err.stderr
new file mode 100644
index 000000000000..ef19f2854ab1
--- /dev/null
+++ b/src/tools/clippy/tests/ui/result_large_err.stderr
@@ -0,0 +1,91 @@
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:8:23
+   |
+LL | pub fn large_err() -> Result<(), [u8; 512]> {
+   |                       ^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 512 bytes
+   |
+   = note: `-D clippy::result-large-err` implied by `-D warnings`
+   = help: try reducing the size of `[u8; 512]`, for example by boxing large elements or replacing it with `Box<[u8; 512]>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:19:21
+   |
+LL |     pub fn ret() -> Result<(), Self> {
+   |                     ^^^^^^^^^^^^^^^^ the `Err`-variant is at least 240 bytes
+   |
+   = help: try reducing the size of `FullyDefinedLargeError`, for example by boxing large elements or replacing it with `Box<FullyDefinedLargeError>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:24:26
+   |
+LL | pub fn struct_error() -> Result<(), FullyDefinedLargeError> {
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 240 bytes
+   |
+   = help: try reducing the size of `FullyDefinedLargeError`, for example by boxing large elements or replacing it with `Box<FullyDefinedLargeError>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:29:45
+   |
+LL | pub fn large_err_via_type_alias<T>(x: T) -> Fdlr<T> {
+   |                                             ^^^^^^^ the `Err`-variant is at least 240 bytes
+   |
+   = help: try reducing the size of `FullyDefinedLargeError`, for example by boxing large elements or replacing it with `Box<FullyDefinedLargeError>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:37:34
+   |
+LL | pub fn param_large_error<R>() -> Result<(), (u128, R, FullyDefinedLargeError)> {
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 256 bytes
+   |
+   = help: try reducing the size of `(u128, R, FullyDefinedLargeError)`, for example by boxing large elements or replacing it with `Box<(u128, R, FullyDefinedLargeError)>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:48:34
+   |
+LL |     pub fn large_enum_error() -> Result<(), Self> {
+   |                                  ^^^^^^^^^^^^^^^^ the `Err`-variant is at least 513 bytes
+   |
+   = help: try reducing the size of `LargeErrorVariants<()>`, for example by boxing large elements or replacing it with `Box<LargeErrorVariants<()>>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:54:25
+   |
+LL |     fn large_error() -> Result<(), [u8; 512]> {
+   |                         ^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 512 bytes
+   |
+   = help: try reducing the size of `[u8; 512]`, for example by boxing large elements or replacing it with `Box<[u8; 512]>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:73:29
+   |
+LL | pub fn large_union_err() -> Result<(), FullyDefinedUnionError> {
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 512 bytes
+   |
+   = help: try reducing the size of `FullyDefinedUnionError`, for example by boxing large elements or replacing it with `Box<FullyDefinedUnionError>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:82:40
+   |
+LL | pub fn param_large_union<T: Copy>() -> Result<(), UnionError<T>> {
+   |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 512 bytes
+   |
+   = help: try reducing the size of `UnionError<T>`, for example by boxing large elements or replacing it with `Box<UnionError<T>>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:91:34
+   |
+LL | pub fn array_error_subst<U>() -> Result<(), ArrayError<i32, U>> {
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 128 bytes
+   |
+   = help: try reducing the size of `ArrayError<i32, U>`, for example by boxing large elements or replacing it with `Box<ArrayError<i32, U>>`
+
+error: the `Err`-variant returned from this function is very large
+  --> $DIR/result_large_err.rs:95:31
+   |
+LL | pub fn array_error<T, U>() -> Result<(), ArrayError<(i32, T), U>> {
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `Err`-variant is at least 128 bytes
+   |
+   = help: try reducing the size of `ArrayError<(i32, T), U>`, for example by boxing large elements or replacing it with `Box<ArrayError<(i32, T), U>>`
+
+error: aborting due to 11 previous errors
+
diff --git a/src/tools/clippy/tests/ui/same_item_push.rs b/src/tools/clippy/tests/ui/same_item_push.rs
index 99964f0de075..af01a8df71b0 100644
--- a/src/tools/clippy/tests/ui/same_item_push.rs
+++ b/src/tools/clippy/tests/ui/same_item_push.rs
@@ -151,6 +151,7 @@ fn main() {
 
     // Fix #6987
     let mut vec = Vec::new();
+    #[allow(clippy::needless_borrow)]
     for _ in 0..10 {
         vec.push(1);
         vec.extend(&[2]);
diff --git a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs
index c3235f06779b..c4dfbd9210e0 100644
--- a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs
+++ b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs
@@ -1,6 +1,5 @@
 #![warn(clippy::semicolon_if_nothing_returned)]
 #![allow(clippy::redundant_closure)]
-#![feature(let_else)]
 
 fn get_unit() {}
 
diff --git a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr
index 78813e7cc1c3..8d9a67585cf1 100644
--- a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr
+++ b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr
@@ -1,5 +1,5 @@
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:9:5
+  --> $DIR/semicolon_if_nothing_returned.rs:8:5
    |
 LL |     println!("Hello")
    |     ^^^^^^^^^^^^^^^^^ help: add a `;` here: `println!("Hello");`
@@ -7,25 +7,25 @@ LL |     println!("Hello")
    = note: `-D clippy::semicolon-if-nothing-returned` implied by `-D warnings`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:13:5
+  --> $DIR/semicolon_if_nothing_returned.rs:12:5
    |
 LL |     get_unit()
    |     ^^^^^^^^^^ help: add a `;` here: `get_unit();`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:18:5
+  --> $DIR/semicolon_if_nothing_returned.rs:17:5
    |
 LL |     y = x + 1
    |     ^^^^^^^^^ help: add a `;` here: `y = x + 1;`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:24:9
+  --> $DIR/semicolon_if_nothing_returned.rs:23:9
    |
 LL |         hello()
    |         ^^^^^^^ help: add a `;` here: `hello();`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:35:9
+  --> $DIR/semicolon_if_nothing_returned.rs:34:9
    |
 LL |         ptr::drop_in_place(s.as_mut_ptr())
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: add a `;` here: `ptr::drop_in_place(s.as_mut_ptr());`
diff --git a/src/tools/clippy/tests/ui/string_add.rs b/src/tools/clippy/tests/ui/string_add.rs
index 30fd17c59e51..16673c01e630 100644
--- a/src/tools/clippy/tests/ui/string_add.rs
+++ b/src/tools/clippy/tests/ui/string_add.rs
@@ -7,13 +7,13 @@ extern crate macro_rules;
 #[allow(clippy::string_add_assign, unused)]
 fn main() {
     // ignores assignment distinction
-    let mut x = "".to_owned();
+    let mut x = String::new();
 
     for _ in 1..3 {
         x = x + ".";
     }
 
-    let y = "".to_owned();
+    let y = String::new();
     let z = y + "...";
 
     assert_eq!(&x, &z);
diff --git a/src/tools/clippy/tests/ui/string_add_assign.fixed b/src/tools/clippy/tests/ui/string_add_assign.fixed
index db71bab1e521..b687f43b2541 100644
--- a/src/tools/clippy/tests/ui/string_add_assign.fixed
+++ b/src/tools/clippy/tests/ui/string_add_assign.fixed
@@ -4,13 +4,13 @@
 #[warn(clippy::string_add_assign)]
 fn main() {
     // ignores assignment distinction
-    let mut x = "".to_owned();
+    let mut x = String::new();
 
     for _ in 1..3 {
         x += ".";
     }
 
-    let y = "".to_owned();
+    let y = String::new();
     let z = y + "...";
 
     assert_eq!(&x, &z);
diff --git a/src/tools/clippy/tests/ui/string_add_assign.rs b/src/tools/clippy/tests/ui/string_add_assign.rs
index 644991945cbe..e5dbde108fbd 100644
--- a/src/tools/clippy/tests/ui/string_add_assign.rs
+++ b/src/tools/clippy/tests/ui/string_add_assign.rs
@@ -4,13 +4,13 @@
 #[warn(clippy::string_add_assign)]
 fn main() {
     // ignores assignment distinction
-    let mut x = "".to_owned();
+    let mut x = String::new();
 
     for _ in 1..3 {
         x = x + ".";
     }
 
-    let y = "".to_owned();
+    let y = String::new();
     let z = y + "...";
 
     assert_eq!(&x, &z);
diff --git a/src/tools/clippy/tests/ui/suspicious_to_owned.rs b/src/tools/clippy/tests/ui/suspicious_to_owned.rs
new file mode 100644
index 000000000000..cba21bf4a93a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/suspicious_to_owned.rs
@@ -0,0 +1,62 @@
+#![warn(clippy::suspicious_to_owned)]
+#![warn(clippy::implicit_clone)]
+#![allow(clippy::redundant_clone)]
+use std::borrow::Cow;
+use std::ffi::{c_char, CStr};
+
+fn main() {
+    let moo = "Moooo";
+    let c_moo = b"Moooo\0";
+    let c_moo_ptr = c_moo.as_ptr() as *const c_char;
+    let moos = ['M', 'o', 'o'];
+    let moos_vec = moos.to_vec();
+
+    // we expect this to be linted
+    let cow = Cow::Borrowed(moo);
+    let _ = cow.to_owned();
+    // we expect no lints for this
+    let cow = Cow::Borrowed(moo);
+    let _ = cow.into_owned();
+    // we expect no lints for this
+    let cow = Cow::Borrowed(moo);
+    let _ = cow.clone();
+
+    // we expect this to be linted
+    let cow = Cow::Borrowed(&moos);
+    let _ = cow.to_owned();
+    // we expect no lints for this
+    let cow = Cow::Borrowed(&moos);
+    let _ = cow.into_owned();
+    // we expect no lints for this
+    let cow = Cow::Borrowed(&moos);
+    let _ = cow.clone();
+
+    // we expect this to be linted
+    let cow = Cow::Borrowed(&moos_vec);
+    let _ = cow.to_owned();
+    // we expect no lints for this
+    let cow = Cow::Borrowed(&moos_vec);
+    let _ = cow.into_owned();
+    // we expect no lints for this
+    let cow = Cow::Borrowed(&moos_vec);
+    let _ = cow.clone();
+
+    // we expect this to be linted
+    let cow = unsafe { CStr::from_ptr(c_moo_ptr) }.to_string_lossy();
+    let _ = cow.to_owned();
+    // we expect no lints for this
+    let cow = unsafe { CStr::from_ptr(c_moo_ptr) }.to_string_lossy();
+    let _ = cow.into_owned();
+    // we expect no lints for this
+    let cow = unsafe { CStr::from_ptr(c_moo_ptr) }.to_string_lossy();
+    let _ = cow.clone();
+
+    // we expect no lints for these
+    let _ = moo.to_owned();
+    let _ = c_moo.to_owned();
+    let _ = moos.to_owned();
+
+    // we expect implicit_clone lints for these
+    let _ = String::from(moo).to_owned();
+    let _ = moos_vec.to_owned();
+}
diff --git a/src/tools/clippy/tests/ui/suspicious_to_owned.stderr b/src/tools/clippy/tests/ui/suspicious_to_owned.stderr
new file mode 100644
index 000000000000..ae1aec34d82e
--- /dev/null
+++ b/src/tools/clippy/tests/ui/suspicious_to_owned.stderr
@@ -0,0 +1,42 @@
+error: this `to_owned` call clones the std::borrow::Cow<'_, str> itself and does not cause the std::borrow::Cow<'_, str> contents to become owned
+  --> $DIR/suspicious_to_owned.rs:16:13
+   |
+LL |     let _ = cow.to_owned();
+   |             ^^^^^^^^^^^^^^ help: consider using, depending on intent: `cow.clone()` or `cow.into_owned()`
+   |
+   = note: `-D clippy::suspicious-to-owned` implied by `-D warnings`
+
+error: this `to_owned` call clones the std::borrow::Cow<'_, [char; 3]> itself and does not cause the std::borrow::Cow<'_, [char; 3]> contents to become owned
+  --> $DIR/suspicious_to_owned.rs:26:13
+   |
+LL |     let _ = cow.to_owned();
+   |             ^^^^^^^^^^^^^^ help: consider using, depending on intent: `cow.clone()` or `cow.into_owned()`
+
+error: this `to_owned` call clones the std::borrow::Cow<'_, std::vec::Vec<char>> itself and does not cause the std::borrow::Cow<'_, std::vec::Vec<char>> contents to become owned
+  --> $DIR/suspicious_to_owned.rs:36:13
+   |
+LL |     let _ = cow.to_owned();
+   |             ^^^^^^^^^^^^^^ help: consider using, depending on intent: `cow.clone()` or `cow.into_owned()`
+
+error: this `to_owned` call clones the std::borrow::Cow<'_, str> itself and does not cause the std::borrow::Cow<'_, str> contents to become owned
+  --> $DIR/suspicious_to_owned.rs:46:13
+   |
+LL |     let _ = cow.to_owned();
+   |             ^^^^^^^^^^^^^^ help: consider using, depending on intent: `cow.clone()` or `cow.into_owned()`
+
+error: implicitly cloning a `String` by calling `to_owned` on its dereferenced type
+  --> $DIR/suspicious_to_owned.rs:60:13
+   |
+LL |     let _ = String::from(moo).to_owned();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `String::from(moo).clone()`
+   |
+   = note: `-D clippy::implicit-clone` implied by `-D warnings`
+
+error: implicitly cloning a `Vec` by calling `to_owned` on its dereferenced type
+  --> $DIR/suspicious_to_owned.rs:61:13
+   |
+LL |     let _ = moos_vec.to_owned();
+   |             ^^^^^^^^^^^^^^^^^^^ help: consider using: `moos_vec.clone()`
+
+error: aborting due to 6 previous errors
+
diff --git a/src/tools/clippy/tests/ui/trait_duplication_in_bounds.fixed b/src/tools/clippy/tests/ui/trait_duplication_in_bounds.fixed
new file mode 100644
index 000000000000..4ce5d4217822
--- /dev/null
+++ b/src/tools/clippy/tests/ui/trait_duplication_in_bounds.fixed
@@ -0,0 +1,112 @@
+// run-rustfix
+#![deny(clippy::trait_duplication_in_bounds)]
+#![allow(unused)]
+
+fn bad_foo<T: Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
+    unimplemented!();
+}
+
+fn bad_bar<T, U>(arg0: T, arg1: U)
+where
+    T: Clone + Copy,
+    U: Clone + Copy,
+{
+    unimplemented!();
+}
+
+fn good_bar<T: Clone + Copy, U: Clone + Copy>(arg0: T, arg1: U) {
+    unimplemented!();
+}
+
+fn good_foo<T, U>(arg0: T, arg1: U)
+where
+    T: Clone + Copy,
+    U: Clone + Copy,
+{
+    unimplemented!();
+}
+
+trait GoodSelfTraitBound: Clone + Copy {
+    fn f();
+}
+
+trait GoodSelfWhereClause {
+    fn f()
+    where
+        Self: Clone + Copy;
+}
+
+trait BadSelfTraitBound: Clone {
+    fn f();
+}
+
+trait BadSelfWhereClause {
+    fn f()
+    where
+        Self: Clone;
+}
+
+trait GoodTraitBound<T: Clone + Copy, U: Clone + Copy> {
+    fn f();
+}
+
+trait GoodWhereClause<T, U> {
+    fn f()
+    where
+        T: Clone + Copy,
+        U: Clone + Copy;
+}
+
+trait BadTraitBound<T: Clone + Copy, U: Clone + Copy> {
+    fn f();
+}
+
+trait BadWhereClause<T, U> {
+    fn f()
+    where
+        T: Clone + Copy,
+        U: Clone + Copy;
+}
+
+struct GoodStructBound<T: Clone + Copy, U: Clone + Copy> {
+    t: T,
+    u: U,
+}
+
+impl<T: Clone + Copy, U: Clone + Copy> GoodTraitBound<T, U> for GoodStructBound<T, U> {
+    // this should not warn
+    fn f() {}
+}
+
+struct GoodStructWhereClause;
+
+impl<T, U> GoodTraitBound<T, U> for GoodStructWhereClause
+where
+    T: Clone + Copy,
+    U: Clone + Copy,
+{
+    // this should not warn
+    fn f() {}
+}
+
+fn no_error_separate_arg_bounds(program: impl AsRef<()>, dir: impl AsRef<()>, args: &[impl AsRef<()>]) {}
+
+trait GenericTrait<T> {}
+
+fn good_generic<T: GenericTrait<u64> + GenericTrait<u32>>(arg0: T) {
+    unimplemented!();
+}
+
+fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32>>(arg0: T) {
+    unimplemented!();
+}
+
+mod foo {
+    pub trait Clone {}
+}
+
+fn qualified_path<T: std::clone::Clone + foo::Clone>(arg0: T) {
+    unimplemented!();
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/trait_duplication_in_bounds.rs b/src/tools/clippy/tests/ui/trait_duplication_in_bounds.rs
index a5751c58aab8..7f2e96a22e66 100644
--- a/src/tools/clippy/tests/ui/trait_duplication_in_bounds.rs
+++ b/src/tools/clippy/tests/ui/trait_duplication_in_bounds.rs
@@ -1,212 +1,112 @@
+// run-rustfix
 #![deny(clippy::trait_duplication_in_bounds)]
 #![allow(unused)]
 
-use std::collections::BTreeMap;
-use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
+fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
+    unimplemented!();
+}
 
-fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
+fn bad_bar<T, U>(arg0: T, arg1: U)
 where
-    T: Clone,
-    T: Default,
+    T: Clone + Clone + Clone + Copy,
+    U: Clone + Copy,
 {
     unimplemented!();
 }
 
-fn good_bar<T: Clone + Default>(arg: T) {
+fn good_bar<T: Clone + Copy, U: Clone + Copy>(arg0: T, arg1: U) {
     unimplemented!();
 }
 
-fn good_foo<T>(arg: T)
+fn good_foo<T, U>(arg0: T, arg1: U)
 where
-    T: Clone + Default,
+    T: Clone + Copy,
+    U: Clone + Copy,
 {
     unimplemented!();
 }
 
-fn good_foobar<T: Default>(arg: T)
-where
-    T: Clone,
-{
-    unimplemented!();
+trait GoodSelfTraitBound: Clone + Copy {
+    fn f();
 }
 
-trait T: Default {
+trait GoodSelfWhereClause {
     fn f()
     where
-        Self: Default;
+        Self: Clone + Copy;
 }
 
-trait U: Default {
+trait BadSelfTraitBound: Clone + Clone + Clone {
+    fn f();
+}
+
+trait BadSelfWhereClause {
     fn f()
     where
-        Self: Clone;
+        Self: Clone + Clone + Clone;
 }
 
-trait ZZ: Default {
-    fn g();
-    fn h();
+trait GoodTraitBound<T: Clone + Copy, U: Clone + Copy> {
+    fn f();
+}
+
+trait GoodWhereClause<T, U> {
     fn f()
     where
-        Self: Default + Clone;
+        T: Clone + Copy,
+        U: Clone + Copy;
 }
 
-trait BadTrait: Default + Clone {
+trait BadTraitBound<T: Clone + Clone + Clone + Copy, U: Clone + Copy> {
+    fn f();
+}
+
+trait BadWhereClause<T, U> {
     fn f()
-    where
-        Self: Default + Clone;
-    fn g()
-    where
-        Self: Default;
-    fn h()
-    where
-        Self: Copy;
-}
-
-#[derive(Default, Clone)]
-struct Life;
-
-impl T for Life {
-    // this should not warn
-    fn f() {}
-}
-
-impl U for Life {
-    // this should not warn
-    fn f() {}
-}
-
-// should not warn
-trait Iter: Iterator {
-    fn into_group_btreemap<K, V>(self) -> BTreeMap<K, Vec<V>>
-    where
-        Self: Iterator<Item = (K, V)> + Sized,
-        K: Ord + Eq,
-    {
-        unimplemented!();
-    }
-}
-
-struct Foo;
-
-trait FooIter: Iterator<Item = Foo> {
-    fn bar()
-    where
-        Self: Iterator<Item = Foo>,
-    {
-    }
-}
-
-// This should not lint
-fn impl_trait(_: impl AsRef<str>, _: impl AsRef<str>) {}
-
-mod repeated_where_clauses_or_trait_bounds {
-    fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
-        unimplemented!();
-    }
-
-    fn bad_bar<T, U>(arg0: T, arg1: U)
     where
         T: Clone + Clone + Clone + Copy,
-        U: Clone + Copy,
-    {
-        unimplemented!();
-    }
+        U: Clone + Copy;
+}
 
-    fn good_bar<T: Clone + Copy, U: Clone + Copy>(arg0: T, arg1: U) {
-        unimplemented!();
-    }
+struct GoodStructBound<T: Clone + Copy, U: Clone + Copy> {
+    t: T,
+    u: U,
+}
 
-    fn good_foo<T, U>(arg0: T, arg1: U)
-    where
-        T: Clone + Copy,
-        U: Clone + Copy,
-    {
-        unimplemented!();
-    }
+impl<T: Clone + Copy, U: Clone + Copy> GoodTraitBound<T, U> for GoodStructBound<T, U> {
+    // this should not warn
+    fn f() {}
+}
 
-    trait GoodSelfTraitBound: Clone + Copy {
-        fn f();
-    }
+struct GoodStructWhereClause;
 
-    trait GoodSelfWhereClause {
-        fn f()
-        where
-            Self: Clone + Copy;
-    }
+impl<T, U> GoodTraitBound<T, U> for GoodStructWhereClause
+where
+    T: Clone + Copy,
+    U: Clone + Copy,
+{
+    // this should not warn
+    fn f() {}
+}
 
-    trait BadSelfTraitBound: Clone + Clone + Clone {
-        fn f();
-    }
+fn no_error_separate_arg_bounds(program: impl AsRef<()>, dir: impl AsRef<()>, args: &[impl AsRef<()>]) {}
 
-    trait BadSelfWhereClause {
-        fn f()
-        where
-            Self: Clone + Clone + Clone;
-    }
+trait GenericTrait<T> {}
 
-    trait GoodTraitBound<T: Clone + Copy, U: Clone + Copy> {
-        fn f();
-    }
+fn good_generic<T: GenericTrait<u64> + GenericTrait<u32>>(arg0: T) {
+    unimplemented!();
+}
 
-    trait GoodWhereClause<T, U> {
-        fn f()
-        where
-            T: Clone + Copy,
-            U: Clone + Copy;
-    }
+fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32> + GenericTrait<u64>>(arg0: T) {
+    unimplemented!();
+}
 
-    trait BadTraitBound<T: Clone + Clone + Clone + Copy, U: Clone + Copy> {
-        fn f();
-    }
+mod foo {
+    pub trait Clone {}
+}
 
-    trait BadWhereClause<T, U> {
-        fn f()
-        where
-            T: Clone + Clone + Clone + Copy,
-            U: Clone + Copy;
-    }
-
-    struct GoodStructBound<T: Clone + Copy, U: Clone + Copy> {
-        t: T,
-        u: U,
-    }
-
-    impl<T: Clone + Copy, U: Clone + Copy> GoodTraitBound<T, U> for GoodStructBound<T, U> {
-        // this should not warn
-        fn f() {}
-    }
-
-    struct GoodStructWhereClause;
-
-    impl<T, U> GoodTraitBound<T, U> for GoodStructWhereClause
-    where
-        T: Clone + Copy,
-        U: Clone + Copy,
-    {
-        // this should not warn
-        fn f() {}
-    }
-
-    fn no_error_separate_arg_bounds(program: impl AsRef<()>, dir: impl AsRef<()>, args: &[impl AsRef<()>]) {}
-
-    trait GenericTrait<T> {}
-
-    // This should not warn but currently does see #8757
-    fn good_generic<T: GenericTrait<u64> + GenericTrait<u32>>(arg0: T) {
-        unimplemented!();
-    }
-
-    fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32> + GenericTrait<u64>>(arg0: T) {
-        unimplemented!();
-    }
-
-    mod foo {
-        pub trait Clone {}
-    }
-
-    fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
-        unimplemented!();
-    }
+fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
+    unimplemented!();
 }
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/trait_duplication_in_bounds.stderr b/src/tools/clippy/tests/ui/trait_duplication_in_bounds.stderr
index 7ef04e52708f..af800ba78880 100644
--- a/src/tools/clippy/tests/ui/trait_duplication_in_bounds.stderr
+++ b/src/tools/clippy/tests/ui/trait_duplication_in_bounds.stderr
@@ -1,167 +1,56 @@
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:7:15
+error: these bounds contain repeated elements
+  --> $DIR/trait_duplication_in_bounds.rs:5:15
    |
-LL | fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
-   |               ^^^^^
+LL | fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
    |
 note: the lint level is defined here
-  --> $DIR/trait_duplication_in_bounds.rs:1:9
+  --> $DIR/trait_duplication_in_bounds.rs:2:9
    |
 LL | #![deny(clippy::trait_duplication_in_bounds)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:7:23
-   |
-LL | fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
-   |                       ^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in trait declaration
-  --> $DIR/trait_duplication_in_bounds.rs:36:15
-   |
-LL |         Self: Default;
-   |               ^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in trait declaration
-  --> $DIR/trait_duplication_in_bounds.rs:50:15
-   |
-LL |         Self: Default + Clone;
-   |               ^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in trait declaration
-  --> $DIR/trait_duplication_in_bounds.rs:56:15
-   |
-LL |         Self: Default + Clone;
-   |               ^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in trait declaration
-  --> $DIR/trait_duplication_in_bounds.rs:56:25
-   |
-LL |         Self: Default + Clone;
-   |                         ^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in trait declaration
-  --> $DIR/trait_duplication_in_bounds.rs:59:15
-   |
-LL |         Self: Default;
-   |               ^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in trait declaration
-  --> $DIR/trait_duplication_in_bounds.rs:94:15
-   |
-LL |         Self: Iterator<Item = Foo>,
-   |               ^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:103:19
-   |
-LL |     fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
-   |                   ^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: these bounds contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:103:19
-   |
-LL |     fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
-   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:109:12
-   |
-LL |         T: Clone + Clone + Clone + Copy,
-   |            ^^^^^
-   |
-   = help: consider removing this trait bound
 
 error: these where clauses contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:109:12
+  --> $DIR/trait_duplication_in_bounds.rs:11:8
+   |
+LL |     T: Clone + Clone + Clone + Copy,
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
+
+error: these bounds contain repeated elements
+  --> $DIR/trait_duplication_in_bounds.rs:39:26
+   |
+LL | trait BadSelfTraitBound: Clone + Clone + Clone {
+   |                          ^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone`
+
+error: these where clauses contain repeated elements
+  --> $DIR/trait_duplication_in_bounds.rs:46:15
+   |
+LL |         Self: Clone + Clone + Clone;
+   |               ^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone`
+
+error: these bounds contain repeated elements
+  --> $DIR/trait_duplication_in_bounds.rs:60:24
+   |
+LL | trait BadTraitBound<T: Clone + Clone + Clone + Copy, U: Clone + Copy> {
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
+
+error: these where clauses contain repeated elements
+  --> $DIR/trait_duplication_in_bounds.rs:67:12
    |
 LL |         T: Clone + Clone + Clone + Copy,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
 
 error: these bounds contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:137:30
+  --> $DIR/trait_duplication_in_bounds.rs:100:19
    |
-LL |     trait BadSelfTraitBound: Clone + Clone + Clone {
-   |                              ^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone`
-
-error: these where clauses contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:144:19
-   |
-LL |             Self: Clone + Clone + Clone;
-   |                   ^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone`
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:158:28
-   |
-LL |     trait BadTraitBound<T: Clone + Clone + Clone + Copy, U: Clone + Copy> {
-   |                            ^^^^^
-   |
-   = help: consider removing this trait bound
+LL | fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32> + GenericTrait<u64>>(arg0: T) {
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `GenericTrait<u64> + GenericTrait<u32>`
 
 error: these bounds contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:158:28
+  --> $DIR/trait_duplication_in_bounds.rs:108:22
    |
-LL |     trait BadTraitBound<T: Clone + Clone + Clone + Copy, U: Clone + Copy> {
-   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
+LL | fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::clone::Clone + foo::Clone`
 
-error: these where clauses contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:165:16
-   |
-LL |             T: Clone + Clone + Clone + Copy,
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:195:24
-   |
-LL |     fn good_generic<T: GenericTrait<u64> + GenericTrait<u32>>(arg0: T) {
-   |                        ^^^^^^^^^^^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:199:23
-   |
-LL |     fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32> + GenericTrait<u64>>(arg0: T) {
-   |                       ^^^^^^^^^^^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: these bounds contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:199:23
-   |
-LL |     fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32> + GenericTrait<u64>>(arg0: T) {
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `GenericTrait<u32> + GenericTrait<u64>`
-
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:207:26
-   |
-LL |     fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
-   |                          ^^^^^^^^^^^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: these bounds contain repeated elements
-  --> $DIR/trait_duplication_in_bounds.rs:207:26
-   |
-LL |     fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
-   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + foo::Clone`
-
-error: aborting due to 22 previous errors
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/trait_duplication_in_bounds_unfixable.rs b/src/tools/clippy/tests/ui/trait_duplication_in_bounds_unfixable.rs
new file mode 100644
index 000000000000..5630a0345adb
--- /dev/null
+++ b/src/tools/clippy/tests/ui/trait_duplication_in_bounds_unfixable.rs
@@ -0,0 +1,166 @@
+#![deny(clippy::trait_duplication_in_bounds)]
+
+use std::collections::BTreeMap;
+use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
+
+fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
+where
+    T: Clone,
+    T: Default,
+{
+    unimplemented!();
+}
+
+fn good_bar<T: Clone + Default>(arg: T) {
+    unimplemented!();
+}
+
+fn good_foo<T>(arg: T)
+where
+    T: Clone + Default,
+{
+    unimplemented!();
+}
+
+fn good_foobar<T: Default>(arg: T)
+where
+    T: Clone,
+{
+    unimplemented!();
+}
+
+trait T: Default {
+    fn f()
+    where
+        Self: Default;
+}
+
+trait U: Default {
+    fn f()
+    where
+        Self: Clone;
+}
+
+trait ZZ: Default {
+    fn g();
+    fn h();
+    fn f()
+    where
+        Self: Default + Clone;
+}
+
+trait BadTrait: Default + Clone {
+    fn f()
+    where
+        Self: Default + Clone;
+    fn g()
+    where
+        Self: Default;
+    fn h()
+    where
+        Self: Copy;
+}
+
+#[derive(Default, Clone)]
+struct Life;
+
+impl T for Life {
+    // this should not warn
+    fn f() {}
+}
+
+impl U for Life {
+    // this should not warn
+    fn f() {}
+}
+
+// should not warn
+trait Iter: Iterator {
+    fn into_group_btreemap<K, V>(self) -> BTreeMap<K, Vec<V>>
+    where
+        Self: Iterator<Item = (K, V)> + Sized,
+        K: Ord + Eq,
+    {
+        unimplemented!();
+    }
+}
+
+struct Foo;
+
+trait FooIter: Iterator<Item = Foo> {
+    fn bar()
+    where
+        Self: Iterator<Item = Foo>,
+    {
+    }
+}
+
+// The below should not lint and exist to guard against false positives
+fn impl_trait(_: impl AsRef<str>, _: impl AsRef<str>) {}
+
+pub mod one {
+    #[derive(Clone, Debug)]
+    struct MultiProductIter<I>
+    where
+        I: Iterator + Clone,
+        I::Item: Clone,
+    {
+        _marker: I,
+    }
+
+    pub struct MultiProduct<I>(Vec<MultiProductIter<I>>)
+    where
+        I: Iterator + Clone,
+        I::Item: Clone;
+
+    pub fn multi_cartesian_product<H>(_: H) -> MultiProduct<<H::Item as IntoIterator>::IntoIter>
+    where
+        H: Iterator,
+        H::Item: IntoIterator,
+        <H::Item as IntoIterator>::IntoIter: Clone,
+        <H::Item as IntoIterator>::Item: Clone,
+    {
+        todo!()
+    }
+}
+
+pub mod two {
+    use std::iter::Peekable;
+
+    pub struct MergeBy<I, J, F>
+    where
+        I: Iterator,
+        J: Iterator<Item = I::Item>,
+    {
+        _i: Peekable<I>,
+        _j: Peekable<J>,
+        _f: F,
+    }
+
+    impl<I, J, F> Clone for MergeBy<I, J, F>
+    where
+        I: Iterator,
+        J: Iterator<Item = I::Item>,
+        std::iter::Peekable<I>: Clone,
+        std::iter::Peekable<J>: Clone,
+        F: Clone,
+    {
+        fn clone(&self) -> Self {
+            Self {
+                _i: self._i.clone(),
+                _j: self._j.clone(),
+                _f: self._f.clone(),
+            }
+        }
+    }
+}
+
+pub trait Trait {}
+
+pub fn f(_a: impl Trait, _b: impl Trait) {}
+
+pub trait ImplTrait<T> {}
+
+impl<A, B> ImplTrait<(A, B)> for Foo where Foo: ImplTrait<A> + ImplTrait<B> {}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/trait_duplication_in_bounds_unfixable.stderr b/src/tools/clippy/tests/ui/trait_duplication_in_bounds_unfixable.stderr
new file mode 100644
index 000000000000..fbd9abb005f1
--- /dev/null
+++ b/src/tools/clippy/tests/ui/trait_duplication_in_bounds_unfixable.stderr
@@ -0,0 +1,71 @@
+error: this trait bound is already specified in the where clause
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:6:15
+   |
+LL | fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
+   |               ^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:1:9
+   |
+LL | #![deny(clippy::trait_duplication_in_bounds)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in the where clause
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:6:23
+   |
+LL | fn bad_foo<T: Clone + Default, Z: Copy>(arg0: T, arg1: Z)
+   |                       ^^^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in trait declaration
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:35:15
+   |
+LL |         Self: Default;
+   |               ^^^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in trait declaration
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:49:15
+   |
+LL |         Self: Default + Clone;
+   |               ^^^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in trait declaration
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:55:15
+   |
+LL |         Self: Default + Clone;
+   |               ^^^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in trait declaration
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:55:25
+   |
+LL |         Self: Default + Clone;
+   |                         ^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in trait declaration
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:58:15
+   |
+LL |         Self: Default;
+   |               ^^^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: this trait bound is already specified in trait declaration
+  --> $DIR/trait_duplication_in_bounds_unfixable.rs:93:15
+   |
+LL |         Self: Iterator<Item = Foo>,
+   |               ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider removing this trait bound
+
+error: aborting due to 8 previous errors
+
diff --git a/src/tools/clippy/tests/ui/transmute_ptr_to_ref.stderr b/src/tools/clippy/tests/ui/transmute_ptr_to_ref.stderr
index 2993e5e7b0c9..10117ee9182a 100644
--- a/src/tools/clippy/tests/ui/transmute_ptr_to_ref.stderr
+++ b/src/tools/clippy/tests/ui/transmute_ptr_to_ref.stderr
@@ -42,13 +42,13 @@ error: transmute from a pointer type (`*mut U`) to a reference type (`&T`)
 LL |     let _: &T = std::mem::transmute(om);
    |                 ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(om as *const T)`
 
-error: transmute from a pointer type (`*const i32`) to a reference type (`&_issue1231::Foo<u8>`)
+error: transmute from a pointer type (`*const i32`) to a reference type (`&_issue1231::Foo<'_, u8>`)
   --> $DIR/transmute_ptr_to_ref.rs:36:32
    |
 LL |     let _: &Foo<u8> = unsafe { std::mem::transmute::<_, &Foo<_>>(raw) };
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*raw.cast::<Foo<_>>()`
 
-error: transmute from a pointer type (`*const i32`) to a reference type (`&_issue1231::Foo<&u8>`)
+error: transmute from a pointer type (`*const i32`) to a reference type (`&_issue1231::Foo<'_, &u8>`)
   --> $DIR/transmute_ptr_to_ref.rs:38:33
    |
 LL |     let _: &Foo<&u8> = unsafe { std::mem::transmute::<_, &Foo<&_>>(raw) };
diff --git a/src/tools/clippy/tests/ui/transmute_undefined_repr.rs b/src/tools/clippy/tests/ui/transmute_undefined_repr.rs
index ebcaa7a84cfb..5aad0b44270a 100644
--- a/src/tools/clippy/tests/ui/transmute_undefined_repr.rs
+++ b/src/tools/clippy/tests/ui/transmute_undefined_repr.rs
@@ -4,6 +4,7 @@
 use core::any::TypeId;
 use core::ffi::c_void;
 use core::mem::{size_of, transmute, MaybeUninit};
+use core::ptr::NonNull;
 
 fn value<T>() -> T {
     unimplemented!()
@@ -109,6 +110,17 @@ fn main() {
         let _: Ty2<u32, u32> = transmute(value::<MaybeUninit<Ty2<u32, u32>>>()); // Ok
 
         let _: Ty<&[u32]> = transmute::<&[u32], _>(value::<&Vec<u32>>()); // Ok
+
+        let _: *const Ty2<u32, u32> = transmute(value::<*const Ty2C<Ty2<u32, u32>, u32>>()); // Ok
+        let _: *const Ty2C<Ty2<u32, u32>, u32> = transmute(value::<*const Ty2<u32, u32>>()); // Ok
+        let _: *const Ty2<u32, u32> = transmute(value::<*const Ty2C<(), Ty2<u32, u32>>>()); // Ok
+        let _: *const Ty2C<(), Ty2<u32, u32>> = transmute(value::<*const Ty2<u32, u32>>()); // Ok
+
+        let _: *const Ty2<u32, u32> = transmute(value::<*const Ty2C<u32, Ty2<u32, u32>>>()); // Err
+        let _: *const Ty2C<u32, Ty2<u32, u32>> = transmute(value::<*const Ty2<u32, u32>>()); // Err
+
+        let _: NonNull<u8> = transmute(value::<NonNull<(String, String)>>()); // Ok
+        let _: NonNull<(String, String)> = transmute(value::<NonNull<u8>>()); // Ok
     }
 }
 
diff --git a/src/tools/clippy/tests/ui/transmute_undefined_repr.stderr b/src/tools/clippy/tests/ui/transmute_undefined_repr.stderr
index 28bfba6c7571..e50a773290e1 100644
--- a/src/tools/clippy/tests/ui/transmute_undefined_repr.stderr
+++ b/src/tools/clippy/tests/ui/transmute_undefined_repr.stderr
@@ -1,5 +1,5 @@
 error: transmute from `Ty2<u32, i32>` which has an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:27:33
+  --> $DIR/transmute_undefined_repr.rs:28:33
    |
 LL |         let _: Ty2C<u32, i32> = transmute(value::<Ty2<u32, i32>>()); // Lint, Ty2 is unordered
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,13 +7,13 @@ LL |         let _: Ty2C<u32, i32> = transmute(value::<Ty2<u32, i32>>()); // Lin
    = note: `-D clippy::transmute-undefined-repr` implied by `-D warnings`
 
 error: transmute into `Ty2<u32, i32>` which has an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:28:32
+  --> $DIR/transmute_undefined_repr.rs:29:32
    |
 LL |         let _: Ty2<u32, i32> = transmute(value::<Ty2C<u32, i32>>()); // Lint, Ty2 is unordered
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from `Ty<Ty2<u32, i32>>` to `Ty2<u32, f32>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:33:32
+  --> $DIR/transmute_undefined_repr.rs:34:32
    |
 LL |         let _: Ty2<u32, f32> = transmute(value::<Ty<Ty2<u32, i32>>>()); // Lint, different Ty2 instances
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -21,7 +21,7 @@ LL |         let _: Ty2<u32, f32> = transmute(value::<Ty<Ty2<u32, i32>>>()); //
    = note: two instances of the same generic type (`Ty2`) may have different layouts
 
 error: transmute from `Ty2<u32, f32>` to `Ty<Ty2<u32, i32>>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:34:36
+  --> $DIR/transmute_undefined_repr.rs:35:36
    |
 LL |         let _: Ty<Ty2<u32, i32>> = transmute(value::<Ty2<u32, f32>>()); // Lint, different Ty2 instances
    |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -29,7 +29,7 @@ LL |         let _: Ty<Ty2<u32, i32>> = transmute(value::<Ty2<u32, f32>>()); //
    = note: two instances of the same generic type (`Ty2`) may have different layouts
 
 error: transmute from `Ty<&Ty2<u32, i32>>` to `&Ty2<u32, f32>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:39:33
+  --> $DIR/transmute_undefined_repr.rs:40:33
    |
 LL |         let _: &Ty2<u32, f32> = transmute(value::<Ty<&Ty2<u32, i32>>>()); // Lint, different Ty2 instances
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -37,7 +37,7 @@ LL |         let _: &Ty2<u32, f32> = transmute(value::<Ty<&Ty2<u32, i32>>>()); /
    = note: two instances of the same generic type (`Ty2`) may have different layouts
 
 error: transmute from `&Ty2<u32, f32>` to `Ty<&Ty2<u32, i32>>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:40:37
+  --> $DIR/transmute_undefined_repr.rs:41:37
    |
 LL |         let _: Ty<&Ty2<u32, i32>> = transmute(value::<&Ty2<u32, f32>>()); // Lint, different Ty2 instances
    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -45,7 +45,7 @@ LL |         let _: Ty<&Ty2<u32, i32>> = transmute(value::<&Ty2<u32, f32>>()); /
    = note: two instances of the same generic type (`Ty2`) may have different layouts
 
 error: transmute from `std::boxed::Box<Ty2<u32, u32>>` to `&mut Ty2<u32, f32>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:57:45
+  --> $DIR/transmute_undefined_repr.rs:58:45
    |
 LL |         let _: &'static mut Ty2<u32, f32> = transmute(value::<Box<Ty2<u32, u32>>>()); // Lint, different Ty2 instances
    |                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -53,15 +53,31 @@ LL |         let _: &'static mut Ty2<u32, f32> = transmute(value::<Box<Ty2<u32,
    = note: two instances of the same generic type (`Ty2`) may have different layouts
 
 error: transmute from `&mut Ty2<u32, f32>` to `std::boxed::Box<Ty2<u32, u32>>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:58:37
+  --> $DIR/transmute_undefined_repr.rs:59:37
    |
 LL |         let _: Box<Ty2<u32, u32>> = transmute(value::<&'static mut Ty2<u32, f32>>()); // Lint, different Ty2 instances
    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: two instances of the same generic type (`Ty2`) may have different layouts
 
+error: transmute into `*const Ty2<u32, u32>` which has an undefined layout
+  --> $DIR/transmute_undefined_repr.rs:119:39
+   |
+LL |         let _: *const Ty2<u32, u32> = transmute(value::<*const Ty2C<u32, Ty2<u32, u32>>>()); // Err
+   |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the contained type `Ty2<u32, u32>` has an undefined layout
+
+error: transmute from `*const Ty2<u32, u32>` which has an undefined layout
+  --> $DIR/transmute_undefined_repr.rs:120:50
+   |
+LL |         let _: *const Ty2C<u32, Ty2<u32, u32>> = transmute(value::<*const Ty2<u32, u32>>()); // Err
+   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the contained type `Ty2<u32, u32>` has an undefined layout
+
 error: transmute from `std::vec::Vec<Ty2<U, i32>>` to `std::vec::Vec<Ty2<T, u32>>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:138:35
+  --> $DIR/transmute_undefined_repr.rs:150:35
    |
 LL |         let _: Vec<Ty2<T, u32>> = transmute(value::<Vec<Ty2<U, i32>>>()); // Err
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -69,12 +85,12 @@ LL |         let _: Vec<Ty2<T, u32>> = transmute(value::<Vec<Ty2<U, i32>>>()); /
    = note: two instances of the same generic type (`Vec`) may have different layouts
 
 error: transmute from `std::vec::Vec<Ty2<T, u32>>` to `std::vec::Vec<Ty2<U, i32>>`, both of which have an undefined layout
-  --> $DIR/transmute_undefined_repr.rs:139:35
+  --> $DIR/transmute_undefined_repr.rs:151:35
    |
 LL |         let _: Vec<Ty2<U, i32>> = transmute(value::<Vec<Ty2<T, u32>>>()); // Err
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: two instances of the same generic type (`Vec`) may have different layouts
 
-error: aborting due to 10 previous errors
+error: aborting due to 12 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unicode.fixed b/src/tools/clippy/tests/ui/unicode.fixed
index 328cda369e11..94b4723452fa 100644
--- a/src/tools/clippy/tests/ui/unicode.fixed
+++ b/src/tools/clippy/tests/ui/unicode.fixed
@@ -1,4 +1,7 @@
 // run-rustfix
+// compile-flags: --test
+#![allow(dead_code)]
+
 #[warn(clippy::invisible_characters)]
 fn zero() {
     print!("Here >\u{200B}< is a ZWS, and \u{200B}another");
@@ -15,22 +18,43 @@ fn canon() {
     print!("a\u{0300}h?"); // also ok
 }
 
-#[warn(clippy::non_ascii_literal)]
-fn uni() {
-    print!("\u{dc}ben!");
-    print!("\u{DC}ben!"); // this is ok
-}
+mod non_ascii_literal {
+    #![deny(clippy::non_ascii_literal)]
 
-// issue 8013
-#[warn(clippy::non_ascii_literal)]
-fn single_quote() {
-    const _EMPTY_BLOCK: char = '\u{25b1}';
-    const _FULL_BLOCK: char = '\u{25b0}';
+    fn uni() {
+        print!("\u{dc}ben!");
+        print!("\u{DC}ben!"); // this is ok
+    }
+
+    // issue 8013
+    fn single_quote() {
+        const _EMPTY_BLOCK: char = '\u{25b1}';
+        const _FULL_BLOCK: char = '\u{25b0}';
+    }
+
+    #[test]
+    pub fn issue_7739() {
+        // Ryū crate: https://github.com/dtolnay/ryu
+    }
+
+    mod issue_8263 {
+        #![deny(clippy::non_ascii_literal)]
+
+        // Re-allow for a single test
+        #[test]
+        #[allow(clippy::non_ascii_literal)]
+        fn allowed() {
+            let _ = "悲しいかな、ここに日本語を書くことはできない。";
+        }
+
+        #[test]
+        fn denied() {
+            let _ = "\u{60b2}\u{3057}\u{3044}\u{304b}\u{306a}\u{3001}\u{3053}\u{3053}\u{306b}\u{65e5}\u{672c}\u{8a9e}\u{3092}\u{66f8}\u{304f}\u{3053}\u{3068}\u{306f}\u{3067}\u{304d}\u{306a}\u{3044}\u{3002}";
+        }
+    }
 }
 
 fn main() {
     zero();
-    uni();
     canon();
-    single_quote();
 }
diff --git a/src/tools/clippy/tests/ui/unicode.rs b/src/tools/clippy/tests/ui/unicode.rs
index 7828d6bcbea7..6ad0b255b948 100644
--- a/src/tools/clippy/tests/ui/unicode.rs
+++ b/src/tools/clippy/tests/ui/unicode.rs
@@ -1,4 +1,7 @@
 // run-rustfix
+// compile-flags: --test
+#![allow(dead_code)]
+
 #[warn(clippy::invisible_characters)]
 fn zero() {
     print!("Here >​< is a ZWS, and ​another");
@@ -15,22 +18,43 @@ fn canon() {
     print!("a\u{0300}h?"); // also ok
 }
 
-#[warn(clippy::non_ascii_literal)]
-fn uni() {
-    print!("Üben!");
-    print!("\u{DC}ben!"); // this is ok
-}
+mod non_ascii_literal {
+    #![deny(clippy::non_ascii_literal)]
 
-// issue 8013
-#[warn(clippy::non_ascii_literal)]
-fn single_quote() {
-    const _EMPTY_BLOCK: char = '▱';
-    const _FULL_BLOCK: char = '▰';
+    fn uni() {
+        print!("Üben!");
+        print!("\u{DC}ben!"); // this is ok
+    }
+
+    // issue 8013
+    fn single_quote() {
+        const _EMPTY_BLOCK: char = '▱';
+        const _FULL_BLOCK: char = '▰';
+    }
+
+    #[test]
+    pub fn issue_7739() {
+        // Ryū crate: https://github.com/dtolnay/ryu
+    }
+
+    mod issue_8263 {
+        #![deny(clippy::non_ascii_literal)]
+
+        // Re-allow for a single test
+        #[test]
+        #[allow(clippy::non_ascii_literal)]
+        fn allowed() {
+            let _ = "悲しいかな、ここに日本語を書くことはできない。";
+        }
+
+        #[test]
+        fn denied() {
+            let _ = "悲しいかな、ここに日本語を書くことはできない。";
+        }
+    }
 }
 
 fn main() {
     zero();
-    uni();
     canon();
-    single_quote();
 }
diff --git a/src/tools/clippy/tests/ui/unicode.stderr b/src/tools/clippy/tests/ui/unicode.stderr
index 01d3f3c02967..ea74a81451e3 100644
--- a/src/tools/clippy/tests/ui/unicode.stderr
+++ b/src/tools/clippy/tests/ui/unicode.stderr
@@ -1,5 +1,5 @@
 error: invisible character detected
-  --> $DIR/unicode.rs:4:12
+  --> $DIR/unicode.rs:7:12
    |
 LL |     print!("Here >​< is a ZWS, and ​another");
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider replacing the string with: `"Here >/u{200B}< is a ZWS, and /u{200B}another"`
@@ -7,19 +7,19 @@ LL |     print!("Here >​< is a ZWS, and ​another");
    = note: `-D clippy::invisible-characters` implied by `-D warnings`
 
 error: invisible character detected
-  --> $DIR/unicode.rs:6:12
+  --> $DIR/unicode.rs:9:12
    |
 LL |     print!("Here >­< is a SHY, and ­another");
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider replacing the string with: `"Here >/u{AD}< is a SHY, and /u{AD}another"`
 
 error: invisible character detected
-  --> $DIR/unicode.rs:8:12
+  --> $DIR/unicode.rs:11:12
    |
 LL |     print!("Here >⁠< is a WJ, and ⁠another");
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider replacing the string with: `"Here >/u{2060}< is a WJ, and /u{2060}another"`
 
 error: non-NFC Unicode sequence detected
-  --> $DIR/unicode.rs:14:12
+  --> $DIR/unicode.rs:17:12
    |
 LL |     print!("̀àh?");
    |            ^^^^^ help: consider replacing the string with: `"̀àh?"`
@@ -27,24 +27,40 @@ LL |     print!("̀àh?");
    = note: `-D clippy::unicode-not-nfc` implied by `-D warnings`
 
 error: literal non-ASCII character detected
-  --> $DIR/unicode.rs:20:12
+  --> $DIR/unicode.rs:25:16
    |
-LL |     print!("Üben!");
-   |            ^^^^^^^ help: consider replacing the string with: `"/u{dc}ben!"`
+LL |         print!("Üben!");
+   |                ^^^^^^^ help: consider replacing the string with: `"/u{dc}ben!"`
    |
-   = note: `-D clippy::non-ascii-literal` implied by `-D warnings`
+note: the lint level is defined here
+  --> $DIR/unicode.rs:22:13
+   |
+LL |     #![deny(clippy::non_ascii_literal)]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: literal non-ASCII character detected
-  --> $DIR/unicode.rs:27:32
+  --> $DIR/unicode.rs:31:36
    |
-LL |     const _EMPTY_BLOCK: char = '▱';
-   |                                ^^^ help: consider replacing the string with: `'/u{25b1}'`
+LL |         const _EMPTY_BLOCK: char = '▱';
+   |                                    ^^^ help: consider replacing the string with: `'/u{25b1}'`
 
 error: literal non-ASCII character detected
-  --> $DIR/unicode.rs:28:31
+  --> $DIR/unicode.rs:32:35
    |
-LL |     const _FULL_BLOCK: char = '▰';
-   |                               ^^^ help: consider replacing the string with: `'/u{25b0}'`
+LL |         const _FULL_BLOCK: char = '▰';
+   |                                   ^^^ help: consider replacing the string with: `'/u{25b0}'`
 
-error: aborting due to 7 previous errors
+error: literal non-ASCII character detected
+  --> $DIR/unicode.rs:52:21
+   |
+LL |             let _ = "悲しいかな、ここに日本語を書くことはできない。";
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider replacing the string with: `"/u{60b2}/u{3057}/u{3044}/u{304b}/u{306a}/u{3001}/u{3053}/u{3053}/u{306b}/u{65e5}/u{672c}/u{8a9e}/u{3092}/u{66f8}/u{304f}/u{3053}/u{3068}/u{306f}/u{3067}/u{304d}/u{306a}/u{3044}/u{3002}"`
+   |
+note: the lint level is defined here
+  --> $DIR/unicode.rs:41:17
+   |
+LL |         #![deny(clippy::non_ascii_literal)]
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unnecessary_cast.fixed b/src/tools/clippy/tests/ui/unnecessary_cast.fixed
index b352b285c862..ee9f157342d4 100644
--- a/src/tools/clippy/tests/ui/unnecessary_cast.fixed
+++ b/src/tools/clippy/tests/ui/unnecessary_cast.fixed
@@ -88,4 +88,13 @@ mod fixable {
     }
 
     type I32Alias = i32;
+
+    fn issue_9380() {
+        let _: i32 = -1_i32;
+        let _: f32 = -(1) as f32;
+        let _: i64 = -1_i64;
+        let _: i64 = -(1.0) as i64;
+
+        let _ = -(1 + 1) as i64;
+    }
 }
diff --git a/src/tools/clippy/tests/ui/unnecessary_cast.rs b/src/tools/clippy/tests/ui/unnecessary_cast.rs
index 6c8cc3effe8f..5b70412424c0 100644
--- a/src/tools/clippy/tests/ui/unnecessary_cast.rs
+++ b/src/tools/clippy/tests/ui/unnecessary_cast.rs
@@ -88,4 +88,13 @@ mod fixable {
     }
 
     type I32Alias = i32;
+
+    fn issue_9380() {
+        let _: i32 = -(1) as i32;
+        let _: f32 = -(1) as f32;
+        let _: i64 = -(1) as i64;
+        let _: i64 = -(1.0) as i64;
+
+        let _ = -(1 + 1) as i64;
+    }
 }
diff --git a/src/tools/clippy/tests/ui/unnecessary_cast.stderr b/src/tools/clippy/tests/ui/unnecessary_cast.stderr
index bad45f0025b2..f7829ff3b0ef 100644
--- a/src/tools/clippy/tests/ui/unnecessary_cast.stderr
+++ b/src/tools/clippy/tests/ui/unnecessary_cast.stderr
@@ -150,5 +150,17 @@ error: casting float literal to `f32` is unnecessary
 LL |         let _ = -1.0 as f32;
    |                 ^^^^^^^^^^^ help: try: `-1.0_f32`
 
-error: aborting due to 25 previous errors
+error: casting integer literal to `i32` is unnecessary
+  --> $DIR/unnecessary_cast.rs:93:22
+   |
+LL |         let _: i32 = -(1) as i32;
+   |                      ^^^^^^^^^^^ help: try: `-1_i32`
+
+error: casting integer literal to `i64` is unnecessary
+  --> $DIR/unnecessary_cast.rs:95:22
+   |
+LL |         let _: i64 = -(1) as i64;
+   |                      ^^^^^^^^^^^ help: try: `-1_i64`
+
+error: aborting due to 27 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.fixed b/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.fixed
index f95f91329a2f..40052c41039e 100644
--- a/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.fixed
+++ b/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.fixed
@@ -12,6 +12,7 @@ fn main() {
     ref_str_argument("");
 
     // should be linted
+    #[allow(clippy::manual_string_new)]
     ref_str_argument("");
 
     // should not be linted
diff --git a/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.rs b/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.rs
index 0cbdc151ed9b..2304dff5192b 100644
--- a/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.rs
+++ b/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.rs
@@ -12,6 +12,7 @@ fn main() {
     ref_str_argument(&String::new());
 
     // should be linted
+    #[allow(clippy::manual_string_new)]
     ref_str_argument(&String::from(""));
 
     // should not be linted
diff --git a/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.stderr b/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.stderr
index 46bc4597b335..1eb198a8675e 100644
--- a/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.stderr
+++ b/src/tools/clippy/tests/ui/unnecessary_owned_empty_strings.stderr
@@ -7,7 +7,7 @@ LL |     ref_str_argument(&String::new());
    = note: `-D clippy::unnecessary-owned-empty-strings` implied by `-D warnings`
 
 error: usage of `&String::from("")` for a function expecting a `&str` argument
-  --> $DIR/unnecessary_owned_empty_strings.rs:15:22
+  --> $DIR/unnecessary_owned_empty_strings.rs:16:22
    |
 LL |     ref_str_argument(&String::from(""));
    |                      ^^^^^^^^^^^^^^^^^ help: try: `""`
diff --git a/src/tools/clippy/tests/ui/unnecessary_to_owned.fixed b/src/tools/clippy/tests/ui/unnecessary_to_owned.fixed
index f4f76cd3dd49..f97583aa22f9 100644
--- a/src/tools/clippy/tests/ui/unnecessary_to_owned.fixed
+++ b/src/tools/clippy/tests/ui/unnecessary_to_owned.fixed
@@ -329,3 +329,100 @@ mod issue_8759_variant {
         rw.set_view(&rw.default_view().to_owned());
     }
 }
+
+mod issue_9317 {
+    #![allow(dead_code)]
+
+    struct Bytes {}
+
+    impl ToString for Bytes {
+        fn to_string(&self) -> String {
+            "123".to_string()
+        }
+    }
+
+    impl AsRef<[u8]> for Bytes {
+        fn as_ref(&self) -> &[u8] {
+            &[1, 2, 3]
+        }
+    }
+
+    fn consume<C: AsRef<[u8]>>(c: C) {
+        let _ = c;
+    }
+
+    pub fn main() {
+        let b = Bytes {};
+        // Should not lint.
+        consume(b.to_string());
+    }
+}
+
+mod issue_9351 {
+    #![allow(dead_code)]
+
+    use std::ops::Deref;
+    use std::path::{Path, PathBuf};
+
+    fn require_deref_path<T: Deref<Target = std::path::Path>>(x: T) -> T {
+        x
+    }
+
+    fn generic_arg_used_elsewhere<T: AsRef<Path>>(_x: T, _y: T) {}
+
+    fn id<T: AsRef<str>>(x: T) -> T {
+        x
+    }
+
+    fn predicates_are_satisfied(_x: impl std::fmt::Write) {}
+
+    // Should lint
+    fn single_return() -> impl AsRef<str> {
+        id("abc")
+    }
+
+    // Should not lint
+    fn multiple_returns(b: bool) -> impl AsRef<str> {
+        if b {
+            return String::new();
+        }
+
+        id("abc".to_string())
+    }
+
+    struct S1(String);
+
+    // Should not lint
+    fn fields1() -> S1 {
+        S1(id("abc".to_string()))
+    }
+
+    struct S2 {
+        s: String,
+    }
+
+    // Should not lint
+    fn fields2() {
+        let mut s = S2 { s: "abc".into() };
+        s.s = id("abc".to_string());
+    }
+
+    pub fn main() {
+        let path = std::path::Path::new("x");
+        let path_buf = path.to_owned();
+
+        // Should not lint.
+        let _x: PathBuf = require_deref_path(path.to_owned());
+        generic_arg_used_elsewhere(path.to_owned(), path_buf);
+        predicates_are_satisfied(id("abc".to_string()));
+    }
+}
+
+mod issue_9504 {
+    #![allow(dead_code)]
+
+    async fn foo<S: AsRef<str>>(_: S) {}
+    async fn bar() {
+        foo(std::path::PathBuf::new().to_string_lossy().to_string()).await;
+    }
+}
diff --git a/src/tools/clippy/tests/ui/unnecessary_to_owned.rs b/src/tools/clippy/tests/ui/unnecessary_to_owned.rs
index fe09a489ab0a..aa5394a56579 100644
--- a/src/tools/clippy/tests/ui/unnecessary_to_owned.rs
+++ b/src/tools/clippy/tests/ui/unnecessary_to_owned.rs
@@ -329,3 +329,100 @@ mod issue_8759_variant {
         rw.set_view(&rw.default_view().to_owned());
     }
 }
+
+mod issue_9317 {
+    #![allow(dead_code)]
+
+    struct Bytes {}
+
+    impl ToString for Bytes {
+        fn to_string(&self) -> String {
+            "123".to_string()
+        }
+    }
+
+    impl AsRef<[u8]> for Bytes {
+        fn as_ref(&self) -> &[u8] {
+            &[1, 2, 3]
+        }
+    }
+
+    fn consume<C: AsRef<[u8]>>(c: C) {
+        let _ = c;
+    }
+
+    pub fn main() {
+        let b = Bytes {};
+        // Should not lint.
+        consume(b.to_string());
+    }
+}
+
+mod issue_9351 {
+    #![allow(dead_code)]
+
+    use std::ops::Deref;
+    use std::path::{Path, PathBuf};
+
+    fn require_deref_path<T: Deref<Target = std::path::Path>>(x: T) -> T {
+        x
+    }
+
+    fn generic_arg_used_elsewhere<T: AsRef<Path>>(_x: T, _y: T) {}
+
+    fn id<T: AsRef<str>>(x: T) -> T {
+        x
+    }
+
+    fn predicates_are_satisfied(_x: impl std::fmt::Write) {}
+
+    // Should lint
+    fn single_return() -> impl AsRef<str> {
+        id("abc".to_string())
+    }
+
+    // Should not lint
+    fn multiple_returns(b: bool) -> impl AsRef<str> {
+        if b {
+            return String::new();
+        }
+
+        id("abc".to_string())
+    }
+
+    struct S1(String);
+
+    // Should not lint
+    fn fields1() -> S1 {
+        S1(id("abc".to_string()))
+    }
+
+    struct S2 {
+        s: String,
+    }
+
+    // Should not lint
+    fn fields2() {
+        let mut s = S2 { s: "abc".into() };
+        s.s = id("abc".to_string());
+    }
+
+    pub fn main() {
+        let path = std::path::Path::new("x");
+        let path_buf = path.to_owned();
+
+        // Should not lint.
+        let _x: PathBuf = require_deref_path(path.to_owned());
+        generic_arg_used_elsewhere(path.to_owned(), path_buf);
+        predicates_are_satisfied(id("abc".to_string()));
+    }
+}
+
+mod issue_9504 {
+    #![allow(dead_code)]
+
+    async fn foo<S: AsRef<str>>(_: S) {}
+    async fn bar() {
+        foo(std::path::PathBuf::new().to_string_lossy().to_string()).await;
+    }
+}
diff --git a/src/tools/clippy/tests/ui/unnecessary_to_owned.stderr b/src/tools/clippy/tests/ui/unnecessary_to_owned.stderr
index 243b4599dba4..7deb90b06f3b 100644
--- a/src/tools/clippy/tests/ui/unnecessary_to_owned.stderr
+++ b/src/tools/clippy/tests/ui/unnecessary_to_owned.stderr
@@ -509,5 +509,11 @@ error: unnecessary use of `to_string`
 LL |         Box::new(build(y.to_string()))
    |                        ^^^^^^^^^^^^^ help: use: `y`
 
-error: aborting due to 78 previous errors
+error: unnecessary use of `to_string`
+  --> $DIR/unnecessary_to_owned.rs:381:12
+   |
+LL |         id("abc".to_string())
+   |            ^^^^^^^^^^^^^^^^^ help: use: `"abc"`
+
+error: aborting due to 79 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unused_peekable.rs b/src/tools/clippy/tests/ui/unused_peekable.rs
new file mode 100644
index 000000000000..7374dfdf92e8
--- /dev/null
+++ b/src/tools/clippy/tests/ui/unused_peekable.rs
@@ -0,0 +1,169 @@
+#![warn(clippy::unused_peekable)]
+#![allow(clippy::no_effect)]
+
+use std::iter::Empty;
+use std::iter::Peekable;
+
+fn main() {
+    invalid();
+    valid();
+}
+
+#[allow(clippy::unused_unit)]
+fn invalid() {
+    let peekable = std::iter::empty::<u32>().peekable();
+
+    // Only lint `new_local`
+    let old_local = std::iter::empty::<u32>().peekable();
+    let new_local = old_local;
+
+    // Behind mut ref
+    let mut by_mut_ref_test = std::iter::empty::<u32>().peekable();
+    let by_mut_ref = &mut by_mut_ref_test;
+
+    // Explicitly returns `Peekable`
+    fn returns_peekable() -> Peekable<Empty<u32>> {
+        std::iter::empty().peekable()
+    }
+
+    let peekable_from_fn = returns_peekable();
+
+    // Using a method not exclusive to `Peekable`
+    let mut peekable_using_iterator_method = std::iter::empty::<u32>().peekable();
+    peekable_using_iterator_method.next();
+
+    // Passed by ref to another function
+    fn takes_ref(_peek: &Peekable<Empty<u32>>) {}
+    let passed_along_ref = std::iter::empty::<u32>().peekable();
+    takes_ref(&passed_along_ref);
+
+    // `by_ref` without `peek`
+    let mut by_ref_test = std::iter::empty::<u32>().peekable();
+    let _by_ref = by_ref_test.by_ref();
+
+    let mut peekable_in_for_loop = std::iter::empty::<u32>().peekable();
+    for x in peekable_in_for_loop {}
+}
+
+fn valid() {
+    fn takes_peekable(_peek: Peekable<Empty<u32>>) {}
+
+    // Passed to another function
+    let passed_along = std::iter::empty::<u32>().peekable();
+    takes_peekable(passed_along);
+
+    // Passed to another method
+    struct PeekableConsumer;
+    impl PeekableConsumer {
+        fn consume(&self, _: Peekable<Empty<u32>>) {}
+        fn consume_mut_ref(&self, _: &mut Peekable<Empty<u32>>) {}
+        fn consume_assoc(_: Peekable<Empty<u32>>) {}
+        fn consume_assoc_mut_ref(_: &mut Peekable<Empty<u32>>) {}
+    }
+    let peekable_consumer = PeekableConsumer;
+
+    let peekable = std::iter::empty::<u32>().peekable();
+    peekable_consumer.consume(peekable);
+
+    let mut peekable = std::iter::empty::<u32>().peekable();
+    peekable_consumer.consume_mut_ref(&mut peekable);
+
+    let peekable = std::iter::empty::<u32>().peekable();
+    PeekableConsumer::consume_assoc(peekable);
+
+    let mut peekable = std::iter::empty::<u32>().peekable();
+    PeekableConsumer::consume_assoc_mut_ref(&mut peekable);
+
+    // `peek` called in another block
+    let mut peekable_in_block = std::iter::empty::<u32>().peekable();
+    {
+        peekable_in_block.peek();
+    }
+
+    // Check the other `Peekable` methods :)
+    {
+        let mut peekable_with_peek_mut = std::iter::empty::<u32>().peekable();
+        peekable_with_peek_mut.peek_mut();
+
+        let mut peekable_with_next_if = std::iter::empty::<u32>().peekable();
+        peekable_with_next_if.next_if(|_| true);
+
+        let mut peekable_with_next_if_eq = std::iter::empty::<u32>().peekable();
+        peekable_with_next_if_eq.next_if_eq(&3);
+    }
+
+    let mut peekable_in_closure = std::iter::empty::<u32>().peekable();
+    let call_peek = |p: &mut Peekable<Empty<u32>>| {
+        p.peek();
+    };
+    call_peek(&mut peekable_in_closure);
+
+    // From a macro
+    macro_rules! make_me_a_peekable_please {
+        () => {
+            std::iter::empty::<u32>().peekable()
+        };
+    }
+
+    let _unsuspecting_macro_user = make_me_a_peekable_please!();
+
+    // Generic Iterator returned
+    fn return_an_iter() -> impl Iterator<Item = u32> {
+        std::iter::empty::<u32>().peekable()
+    }
+
+    let _unsuspecting_user = return_an_iter();
+
+    // Call `peek` in a macro
+    macro_rules! peek_iter {
+        ($iter:ident) => {
+            $iter.peek();
+        };
+    }
+
+    let mut peek_in_macro = std::iter::empty::<u32>().peekable();
+    peek_iter!(peek_in_macro);
+
+    // Behind mut ref
+    let mut by_mut_ref_test = std::iter::empty::<u32>().peekable();
+    let by_mut_ref = &mut by_mut_ref_test;
+    by_mut_ref.peek();
+
+    // Behind ref
+    let mut by_ref_test = std::iter::empty::<u32>().peekable();
+    let by_ref = &by_ref_test;
+    by_ref_test.peek();
+
+    // In struct
+    struct PeekableWrapper {
+        f: Peekable<Empty<u32>>,
+    }
+
+    let struct_test = std::iter::empty::<u32>().peekable();
+    PeekableWrapper { f: struct_test };
+
+    // `by_ref` before `peek`
+    let mut by_ref_test = std::iter::empty::<u32>().peekable();
+    let peeked_val = by_ref_test.by_ref().peek();
+
+    // `peek` called in another block as the last expression
+    let mut peekable_last_expr = std::iter::empty::<u32>().peekable();
+    {
+        peekable_last_expr.peek();
+    }
+
+    let mut peek_in_closure = std::iter::empty::<u32>().peekable();
+    let _ = || {
+        let _ = peek_in_closure.peek();
+    };
+
+    trait PeekTrait {}
+    impl<I> PeekTrait for Peekable<I> where I: Iterator {}
+
+    let mut peekable = std::iter::empty::<u32>().peekable();
+    let _dyn = &mut peekable as &mut dyn PeekTrait;
+
+    fn takes_dyn(_: &mut dyn PeekTrait) {}
+    let mut peekable = std::iter::empty::<u32>().peekable();
+    takes_dyn(&mut peekable);
+}
diff --git a/src/tools/clippy/tests/ui/unused_peekable.stderr b/src/tools/clippy/tests/ui/unused_peekable.stderr
new file mode 100644
index 000000000000..d557f54179db
--- /dev/null
+++ b/src/tools/clippy/tests/ui/unused_peekable.stderr
@@ -0,0 +1,67 @@
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:14:9
+   |
+LL |     let peekable = std::iter::empty::<u32>().peekable();
+   |         ^^^^^^^^
+   |
+   = note: `-D clippy::unused-peekable` implied by `-D warnings`
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:18:9
+   |
+LL |     let new_local = old_local;
+   |         ^^^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:22:9
+   |
+LL |     let by_mut_ref = &mut by_mut_ref_test;
+   |         ^^^^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:29:9
+   |
+LL |     let peekable_from_fn = returns_peekable();
+   |         ^^^^^^^^^^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:32:13
+   |
+LL |     let mut peekable_using_iterator_method = std::iter::empty::<u32>().peekable();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:37:9
+   |
+LL |     let passed_along_ref = std::iter::empty::<u32>().peekable();
+   |         ^^^^^^^^^^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:42:9
+   |
+LL |     let _by_ref = by_ref_test.by_ref();
+   |         ^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: `peek` never called on `Peekable` iterator
+  --> $DIR/unused_peekable.rs:44:13
+   |
+LL |     let mut peekable_in_for_loop = std::iter::empty::<u32>().peekable();
+   |             ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider removing the call to `peekable`
+
+error: aborting due to 8 previous errors
+
diff --git a/src/tools/clippy/tests/ui/unwrap.rs b/src/tools/clippy/tests/ui/unwrap.rs
index a4a3cd1d3797..d9fd402e7cfb 100644
--- a/src/tools/clippy/tests/ui/unwrap.rs
+++ b/src/tools/clippy/tests/ui/unwrap.rs
@@ -6,8 +6,9 @@ fn unwrap_option() {
 }
 
 fn unwrap_result() {
-    let res: Result<u8, ()> = Ok(0);
+    let res: Result<u8, u8> = Ok(0);
     let _ = res.unwrap();
+    let _ = res.unwrap_err();
 }
 
 fn main() {
diff --git a/src/tools/clippy/tests/ui/unwrap.stderr b/src/tools/clippy/tests/ui/unwrap.stderr
index 4f0858005f6e..78422757819d 100644
--- a/src/tools/clippy/tests/ui/unwrap.stderr
+++ b/src/tools/clippy/tests/ui/unwrap.stderr
@@ -15,5 +15,13 @@ LL |     let _ = res.unwrap();
    |
    = help: if you don't want to handle the `Err` case gracefully, consider using `expect()` to provide a better panic message
 
-error: aborting due to 2 previous errors
+error: used `unwrap_err()` on `a Result` value
+  --> $DIR/unwrap.rs:11:13
+   |
+LL |     let _ = res.unwrap_err();
+   |             ^^^^^^^^^^^^^^^^
+   |
+   = help: if you don't want to handle the `Ok` case gracefully, consider using `expect_err()` to provide a better panic message
+
+error: aborting due to 3 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unwrap_expect_used.rs b/src/tools/clippy/tests/ui/unwrap_expect_used.rs
index 0d4a0504a6e0..9f27fef82494 100644
--- a/src/tools/clippy/tests/ui/unwrap_expect_used.rs
+++ b/src/tools/clippy/tests/ui/unwrap_expect_used.rs
@@ -1,10 +1,35 @@
 #![warn(clippy::unwrap_used, clippy::expect_used)]
 
+trait OptionExt {
+    type Item;
+
+    fn unwrap_err(self) -> Self::Item;
+
+    fn expect_err(self, msg: &str) -> Self::Item;
+}
+
+impl<T> OptionExt for Option<T> {
+    type Item = T;
+    fn unwrap_err(self) -> T {
+        panic!();
+    }
+
+    fn expect_err(self, msg: &str) -> T {
+        panic!();
+    }
+}
+
 fn main() {
     Some(3).unwrap();
     Some(3).expect("Hello world!");
 
+    // Don't trigger on unwrap_err on an option
+    Some(3).unwrap_err();
+    Some(3).expect_err("Hellow none!");
+
     let a: Result<i32, i32> = Ok(3);
     a.unwrap();
     a.expect("Hello world!");
+    a.unwrap_err();
+    a.expect_err("Hello error!");
 }
diff --git a/src/tools/clippy/tests/ui/unwrap_expect_used.stderr b/src/tools/clippy/tests/ui/unwrap_expect_used.stderr
index f54bfd617c4e..1a19459b2c17 100644
--- a/src/tools/clippy/tests/ui/unwrap_expect_used.stderr
+++ b/src/tools/clippy/tests/ui/unwrap_expect_used.stderr
@@ -1,5 +1,5 @@
 error: used `unwrap()` on `an Option` value
-  --> $DIR/unwrap_expect_used.rs:4:5
+  --> $DIR/unwrap_expect_used.rs:23:5
    |
 LL |     Some(3).unwrap();
    |     ^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL |     Some(3).unwrap();
    = help: if this value is `None`, it will panic
 
 error: used `expect()` on `an Option` value
-  --> $DIR/unwrap_expect_used.rs:5:5
+  --> $DIR/unwrap_expect_used.rs:24:5
    |
 LL |     Some(3).expect("Hello world!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -17,7 +17,7 @@ LL |     Some(3).expect("Hello world!");
    = help: if this value is `None`, it will panic
 
 error: used `unwrap()` on `a Result` value
-  --> $DIR/unwrap_expect_used.rs:8:5
+  --> $DIR/unwrap_expect_used.rs:31:5
    |
 LL |     a.unwrap();
    |     ^^^^^^^^^^
@@ -25,12 +25,28 @@ LL |     a.unwrap();
    = help: if this value is an `Err`, it will panic
 
 error: used `expect()` on `a Result` value
-  --> $DIR/unwrap_expect_used.rs:9:5
+  --> $DIR/unwrap_expect_used.rs:32:5
    |
 LL |     a.expect("Hello world!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: if this value is an `Err`, it will panic
 
-error: aborting due to 4 previous errors
+error: used `unwrap_err()` on `a Result` value
+  --> $DIR/unwrap_expect_used.rs:33:5
+   |
+LL |     a.unwrap_err();
+   |     ^^^^^^^^^^^^^^
+   |
+   = help: if this value is an `Ok`, it will panic
+
+error: used `expect_err()` on `a Result` value
+  --> $DIR/unwrap_expect_used.rs:34:5
+   |
+LL |     a.expect_err("Hello error!");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: if this value is an `Ok`, it will panic
+
+error: aborting due to 6 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unwrap_or_else_default.fixed b/src/tools/clippy/tests/ui/unwrap_or_else_default.fixed
index c2b9bd2c881f..84f779569ff9 100644
--- a/src/tools/clippy/tests/ui/unwrap_or_else_default.fixed
+++ b/src/tools/clippy/tests/ui/unwrap_or_else_default.fixed
@@ -69,6 +69,9 @@ fn unwrap_or_else_default() {
 
     let with_default_type: Option<Vec<u64>> = None;
     with_default_type.unwrap_or_default();
+
+    let empty_string = None::<String>;
+    empty_string.unwrap_or_default();
 }
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/unwrap_or_else_default.rs b/src/tools/clippy/tests/ui/unwrap_or_else_default.rs
index d55664990aeb..1735bd5808e5 100644
--- a/src/tools/clippy/tests/ui/unwrap_or_else_default.rs
+++ b/src/tools/clippy/tests/ui/unwrap_or_else_default.rs
@@ -69,6 +69,9 @@ fn unwrap_or_else_default() {
 
     let with_default_type: Option<Vec<u64>> = None;
     with_default_type.unwrap_or_else(Vec::new);
+
+    let empty_string = None::<String>;
+    empty_string.unwrap_or_else(|| "".to_string());
 }
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr b/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr
index 53e31d85edfc..d2b9212223f7 100644
--- a/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr
+++ b/src/tools/clippy/tests/ui/unwrap_or_else_default.stderr
@@ -30,5 +30,11 @@ error: use of `.unwrap_or_else(..)` to construct default value
 LL |     with_default_type.unwrap_or_else(Vec::new);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `with_default_type.unwrap_or_default()`
 
-error: aborting due to 5 previous errors
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:74:5
+   |
+LL |     empty_string.unwrap_or_else(|| "".to_string());
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `empty_string.unwrap_or_default()`
+
+error: aborting due to 6 previous errors
 
diff --git a/src/tools/clippy/tests/ui/use_self.fixed b/src/tools/clippy/tests/ui/use_self.fixed
index 4f80aaecc902..37986187da17 100644
--- a/src/tools/clippy/tests/ui/use_self.fixed
+++ b/src/tools/clippy/tests/ui/use_self.fixed
@@ -608,3 +608,12 @@ mod issue8845 {
         }
     }
 }
+
+mod issue6902 {
+    use serde::Serialize;
+
+    #[derive(Serialize)]
+    pub enum Foo {
+        Bar = 1,
+    }
+}
diff --git a/src/tools/clippy/tests/ui/use_self.rs b/src/tools/clippy/tests/ui/use_self.rs
index 52da72db53ce..1b2b3337c92e 100644
--- a/src/tools/clippy/tests/ui/use_self.rs
+++ b/src/tools/clippy/tests/ui/use_self.rs
@@ -608,3 +608,12 @@ mod issue8845 {
         }
     }
 }
+
+mod issue6902 {
+    use serde::Serialize;
+
+    #[derive(Serialize)]
+    pub enum Foo {
+        Bar = 1,
+    }
+}
diff --git a/src/tools/clippy/tests/ui/useless_conversion.stderr b/src/tools/clippy/tests/ui/useless_conversion.stderr
index e6760f700f34..65ee3807fa9d 100644
--- a/src/tools/clippy/tests/ui/useless_conversion.stderr
+++ b/src/tools/clippy/tests/ui/useless_conversion.stderr
@@ -46,7 +46,7 @@ error: useless conversion to the same type: `std::string::String`
 LL |     let _ = String::from(format!("A: {:04}", 123));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `String::from()`: `format!("A: {:04}", 123)`
 
-error: useless conversion to the same type: `std::str::Lines`
+error: useless conversion to the same type: `std::str::Lines<'_>`
   --> $DIR/useless_conversion.rs:65:13
    |
 LL |     let _ = "".lines().into_iter();
diff --git a/src/tools/clippy/tests/ui/useless_conversion_try.rs b/src/tools/clippy/tests/ui/useless_conversion_try.rs
index 39f54c27bee1..4acf5b5fa2d1 100644
--- a/src/tools/clippy/tests/ui/useless_conversion_try.rs
+++ b/src/tools/clippy/tests/ui/useless_conversion_try.rs
@@ -29,10 +29,10 @@ fn main() {
     let _ = String::try_from("foo".to_string()).unwrap();
     let _ = String::try_from(format!("A: {:04}", 123)).unwrap();
     let _: String = format!("Hello {}", "world").try_into().unwrap();
-    let _: String = "".to_owned().try_into().unwrap();
+    let _: String = String::new().try_into().unwrap();
     let _: String = match String::from("_").try_into() {
         Ok(a) => a,
-        Err(_) => "".into(),
+        Err(_) => String::new(),
     };
     // FIXME this is a false negative
     #[allow(clippy::cmp_owned)]
diff --git a/src/tools/clippy/tests/ui/useless_conversion_try.stderr b/src/tools/clippy/tests/ui/useless_conversion_try.stderr
index b691c13f7dbb..12e74d614717 100644
--- a/src/tools/clippy/tests/ui/useless_conversion_try.stderr
+++ b/src/tools/clippy/tests/ui/useless_conversion_try.stderr
@@ -62,7 +62,7 @@ LL |     let _: String = format!("Hello {}", "world").try_into().unwrap();
 error: useless conversion to the same type: `std::string::String`
   --> $DIR/useless_conversion_try.rs:32:21
    |
-LL |     let _: String = "".to_owned().try_into().unwrap();
+LL |     let _: String = String::new().try_into().unwrap();
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider removing `.try_into()`
diff --git a/src/tools/clippy/tests/ui/vec_init_then_push.rs b/src/tools/clippy/tests/ui/vec_init_then_push.rs
index 531745424a7d..8dd098a5b540 100644
--- a/src/tools/clippy/tests/ui/vec_init_then_push.rs
+++ b/src/tools/clippy/tests/ui/vec_init_then_push.rs
@@ -104,3 +104,9 @@ fn _cond_push_with_large_start(x: bool) -> Vec<u32> {
 
     v2
 }
+
+fn f() {
+    let mut v = Vec::new();
+    v.push((0i32, 0i32));
+    let y = v[0].0.abs();
+}
diff --git a/src/tools/clippy/tests/ui/vec_init_then_push.stderr b/src/tools/clippy/tests/ui/vec_init_then_push.stderr
index 50b029fc3372..a9da1c520197 100644
--- a/src/tools/clippy/tests/ui/vec_init_then_push.stderr
+++ b/src/tools/clippy/tests/ui/vec_init_then_push.stderr
@@ -62,5 +62,12 @@ LL | |     v2.push(1);
 LL | |     v2.push(0);
    | |_______________^ help: consider using the `vec![]` macro: `let mut v2 = vec![..];`
 
-error: aborting due to 7 previous errors
+error: calls to `push` immediately after creation
+  --> $DIR/vec_init_then_push.rs:109:5
+   |
+LL | /     let mut v = Vec::new();
+LL | |     v.push((0i32, 0i32));
+   | |_________________________^ help: consider using the `vec![]` macro: `let v = vec![..];`
+
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/vec_resize_to_zero.rs b/src/tools/clippy/tests/ui/vec_resize_to_zero.rs
index 7ed27439ec6e..a8307e741cf1 100644
--- a/src/tools/clippy/tests/ui/vec_resize_to_zero.rs
+++ b/src/tools/clippy/tests/ui/vec_resize_to_zero.rs
@@ -1,15 +1,19 @@
 #![warn(clippy::vec_resize_to_zero)]
 
 fn main() {
+    let mut v = vec![1, 2, 3, 4, 5];
+
     // applicable here
-    vec![1, 2, 3, 4, 5].resize(0, 5);
+    v.resize(0, 5);
 
     // not applicable
-    vec![1, 2, 3, 4, 5].resize(2, 5);
+    v.resize(2, 5);
+
+    let mut v = vec!["foo", "bar", "baz"];
 
     // applicable here, but only implemented for integer literals for now
-    vec!["foo", "bar", "baz"].resize(0, "bar");
+    v.resize(0, "bar");
 
     // not applicable
-    vec!["foo", "bar", "baz"].resize(2, "bar")
+    v.resize(2, "bar")
 }
diff --git a/src/tools/clippy/tests/ui/vec_resize_to_zero.stderr b/src/tools/clippy/tests/ui/vec_resize_to_zero.stderr
index feb846298c65..7428cf62d6c4 100644
--- a/src/tools/clippy/tests/ui/vec_resize_to_zero.stderr
+++ b/src/tools/clippy/tests/ui/vec_resize_to_zero.stderr
@@ -1,10 +1,10 @@
 error: emptying a vector with `resize`
-  --> $DIR/vec_resize_to_zero.rs:5:5
+  --> $DIR/vec_resize_to_zero.rs:7:5
    |
-LL |     vec![1, 2, 3, 4, 5].resize(0, 5);
-   |     ^^^^^^^^^^^^^^^^^^^^------------
-   |                         |
-   |                         help: ...or you can empty the vector with: `clear()`
+LL |     v.resize(0, 5);
+   |     ^^------------
+   |       |
+   |       help: ...or you can empty the vector with: `clear()`
    |
    = note: `-D clippy::vec-resize-to-zero` implied by `-D warnings`
    = help: the arguments may be inverted...
diff --git a/src/tools/clippy/tests/ui/verbose_file_reads.rs b/src/tools/clippy/tests/ui/verbose_file_reads.rs
index e0065e05ade6..df267e9872a0 100644
--- a/src/tools/clippy/tests/ui/verbose_file_reads.rs
+++ b/src/tools/clippy/tests/ui/verbose_file_reads.rs
@@ -18,7 +18,7 @@ fn main() -> std::io::Result<()> {
     s.read_to_end();
     s.read_to_string();
     // Should catch this
-    let mut f = File::open(&path)?;
+    let mut f = File::open(path)?;
     let mut buffer = Vec::new();
     f.read_to_end(&mut buffer)?;
     // ...and this
diff --git a/src/tools/clippy/tests/ui/write_literal.rs b/src/tools/clippy/tests/ui/write_literal.rs
index 446691744116..5892818aa9a6 100644
--- a/src/tools/clippy/tests/ui/write_literal.rs
+++ b/src/tools/clippy/tests/ui/write_literal.rs
@@ -25,11 +25,13 @@ fn main() {
     writeln!(v, "{} of {:b} people know binary, the other half doesn't", 1, 2);
     writeln!(v, "10 / 4 is {}", 2.5);
     writeln!(v, "2 + 1 = {}", 3);
+    writeln!(v, "From expansion {}", stringify!(not a string literal));
 
     // these should throw warnings
     write!(v, "Hello {}", "world");
     writeln!(v, "Hello {} {}", world, "world");
     writeln!(v, "Hello {}", "world");
+    writeln!(v, "{} {:.4}", "a literal", 5);
 
     // positional args don't change the fact
     // that we're using a literal -- this should
diff --git a/src/tools/clippy/tests/ui/write_literal.stderr b/src/tools/clippy/tests/ui/write_literal.stderr
index 3c5ec91d3e0f..1e306ae28a26 100644
--- a/src/tools/clippy/tests/ui/write_literal.stderr
+++ b/src/tools/clippy/tests/ui/write_literal.stderr
@@ -1,5 +1,5 @@
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:30:27
+  --> $DIR/write_literal.rs:31:27
    |
 LL |     write!(v, "Hello {}", "world");
    |                           ^^^^^^^
@@ -12,7 +12,7 @@ LL +     write!(v, "Hello world");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:31:39
+  --> $DIR/write_literal.rs:32:39
    |
 LL |     writeln!(v, "Hello {} {}", world, "world");
    |                                       ^^^^^^^
@@ -24,7 +24,7 @@ LL +     writeln!(v, "Hello {} world", world);
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:32:29
+  --> $DIR/write_literal.rs:33:29
    |
 LL |     writeln!(v, "Hello {}", "world");
    |                             ^^^^^^^
@@ -36,7 +36,19 @@ LL +     writeln!(v, "Hello world");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:37:28
+  --> $DIR/write_literal.rs:34:29
+   |
+LL |     writeln!(v, "{} {:.4}", "a literal", 5);
+   |                             ^^^^^^^^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, "{} {:.4}", "a literal", 5);
+LL +     writeln!(v, "a literal {:.4}", 5);
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal.rs:39:28
    |
 LL |     writeln!(v, "{0} {1}", "hello", "world");
    |                            ^^^^^^^
@@ -48,7 +60,7 @@ LL +     writeln!(v, "hello {1}", "world");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:37:37
+  --> $DIR/write_literal.rs:39:37
    |
 LL |     writeln!(v, "{0} {1}", "hello", "world");
    |                                     ^^^^^^^
@@ -60,19 +72,7 @@ LL +     writeln!(v, "{0} world", "hello");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:38:28
-   |
-LL |     writeln!(v, "{1} {0}", "hello", "world");
-   |                            ^^^^^^^
-   |
-help: try this
-   |
-LL -     writeln!(v, "{1} {0}", "hello", "world");
-LL +     writeln!(v, "{1} hello", "world");
-   |
-
-error: literal with an empty format string
-  --> $DIR/write_literal.rs:38:37
+  --> $DIR/write_literal.rs:40:37
    |
 LL |     writeln!(v, "{1} {0}", "hello", "world");
    |                                     ^^^^^^^
@@ -84,10 +84,22 @@ LL +     writeln!(v, "world {0}", "hello");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:41:32
+  --> $DIR/write_literal.rs:40:28
+   |
+LL |     writeln!(v, "{1} {0}", "hello", "world");
+   |                            ^^^^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, "{1} {0}", "hello", "world");
+LL +     writeln!(v, "{1} hello", "world");
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal.rs:43:38
    |
 LL |     writeln!(v, "{foo} {bar}", foo = "hello", bar = "world");
-   |                                ^^^^^^^^^^^^^
+   |                                      ^^^^^^^
    |
 help: try this
    |
@@ -96,10 +108,10 @@ LL +     writeln!(v, "hello {bar}", bar = "world");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:41:47
+  --> $DIR/write_literal.rs:43:53
    |
 LL |     writeln!(v, "{foo} {bar}", foo = "hello", bar = "world");
-   |                                               ^^^^^^^^^^^^^
+   |                                                     ^^^^^^^
    |
 help: try this
    |
@@ -108,22 +120,10 @@ LL +     writeln!(v, "{foo} world", foo = "hello");
    |
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:42:32
+  --> $DIR/write_literal.rs:44:53
    |
 LL |     writeln!(v, "{bar} {foo}", foo = "hello", bar = "world");
-   |                                ^^^^^^^^^^^^^
-   |
-help: try this
-   |
-LL -     writeln!(v, "{bar} {foo}", foo = "hello", bar = "world");
-LL +     writeln!(v, "{bar} hello", bar = "world");
-   |
-
-error: literal with an empty format string
-  --> $DIR/write_literal.rs:42:47
-   |
-LL |     writeln!(v, "{bar} {foo}", foo = "hello", bar = "world");
-   |                                               ^^^^^^^^^^^^^
+   |                                                     ^^^^^^^
    |
 help: try this
    |
@@ -131,5 +131,17 @@ LL -     writeln!(v, "{bar} {foo}", foo = "hello", bar = "world");
 LL +     writeln!(v, "world {foo}", foo = "hello");
    |
 
-error: aborting due to 11 previous errors
+error: literal with an empty format string
+  --> $DIR/write_literal.rs:44:38
+   |
+LL |     writeln!(v, "{bar} {foo}", foo = "hello", bar = "world");
+   |                                      ^^^^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, "{bar} {foo}", foo = "hello", bar = "world");
+LL +     writeln!(v, "{bar} hello", bar = "world");
+   |
+
+error: aborting due to 12 previous errors
 
diff --git a/src/tools/clippy/tests/ui/write_literal_2.rs b/src/tools/clippy/tests/ui/write_literal_2.rs
index ba0d7be5eaa6..55a11daa1d34 100644
--- a/src/tools/clippy/tests/ui/write_literal_2.rs
+++ b/src/tools/clippy/tests/ui/write_literal_2.rs
@@ -10,7 +10,7 @@ fn main() {
     writeln!(v, r"{}", r"{hello}");
     writeln!(v, "{}", '\'');
     writeln!(v, "{}", '"');
-    writeln!(v, r"{}", '"'); // don't lint
+    writeln!(v, r"{}", '"');
     writeln!(v, r"{}", '\'');
     writeln!(
         v,
@@ -24,4 +24,11 @@ fn main() {
         {} \\ {}",
         "1", "2", "3",
     );
+    writeln!(v, "{}", "\\");
+    writeln!(v, r"{}", "\\");
+    writeln!(v, r#"{}"#, "\\");
+    writeln!(v, "{}", r"\");
+    writeln!(v, "{}", "\r");
+    writeln!(v, r#"{}{}"#, '#', '"'); // hard mode
+    writeln!(v, r"{}", "\r"); // should not lint
 }
diff --git a/src/tools/clippy/tests/ui/write_literal_2.stderr b/src/tools/clippy/tests/ui/write_literal_2.stderr
index 9ff297069c40..d5956db9ff0b 100644
--- a/src/tools/clippy/tests/ui/write_literal_2.stderr
+++ b/src/tools/clippy/tests/ui/write_literal_2.stderr
@@ -47,6 +47,12 @@ LL -     writeln!(v, "{}", '"');
 LL +     writeln!(v, "/"");
    |
 
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:13:24
+   |
+LL |     writeln!(v, r"{}", '"');
+   |                        ^^^
+
 error: literal with an empty format string
   --> $DIR/write_literal_2.rs:14:24
    |
@@ -108,5 +114,77 @@ LL ~         {} / 3",
 LL ~         "1", "2",
    |
 
-error: aborting due to 9 previous errors
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:27:23
+   |
+LL |     writeln!(v, "{}", "/");
+   |                       ^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, "{}", "/");
+LL +     writeln!(v, "/");
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:28:24
+   |
+LL |     writeln!(v, r"{}", "/");
+   |                        ^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, r"{}", "/");
+LL +     writeln!(v, r"/");
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:29:26
+   |
+LL |     writeln!(v, r#"{}"#, "/");
+   |                          ^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, r#"{}"#, "/");
+LL +     writeln!(v, r#"/"#);
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:30:23
+   |
+LL |     writeln!(v, "{}", r"/");
+   |                       ^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, "{}", r"/");
+LL +     writeln!(v, "/");
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:31:23
+   |
+LL |     writeln!(v, "{}", "/r");
+   |                       ^^^^
+   |
+help: try this
+   |
+LL -     writeln!(v, "{}", "/r");
+LL +     writeln!(v, "/r");
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:32:28
+   |
+LL |     writeln!(v, r#"{}{}"#, '#', '"'); // hard mode
+   |                            ^^^
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:32:33
+   |
+LL |     writeln!(v, r#"{}{}"#, '#', '"'); // hard mode
+   |                                 ^^^
+
+error: aborting due to 17 previous errors
 
diff --git a/src/tools/clippy/tests/ui/write_with_newline.rs b/src/tools/clippy/tests/ui/write_with_newline.rs
index 446d6914d346..b79364c8758c 100644
--- a/src/tools/clippy/tests/ui/write_with_newline.rs
+++ b/src/tools/clippy/tests/ui/write_with_newline.rs
@@ -56,4 +56,12 @@ fn main() {
     write!(v, "foo\r\n");
     write!(v, "\\r\n"); //~ ERROR
     write!(v, "foo\rbar\n");
+
+    // Ignore expanded format strings
+    macro_rules! newline {
+        () => {
+            "\n"
+        };
+    }
+    write!(v, newline!());
 }
diff --git a/src/tools/clippy/tests/ui/write_with_newline.stderr b/src/tools/clippy/tests/ui/write_with_newline.stderr
index 5f55431be0bd..2baaea166d8e 100644
--- a/src/tools/clippy/tests/ui/write_with_newline.stderr
+++ b/src/tools/clippy/tests/ui/write_with_newline.stderr
@@ -5,7 +5,7 @@ LL |     write!(v, "Hello/n");
    |     ^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::write-with-newline` implied by `-D warnings`
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "Hello/n");
 LL +     writeln!(v, "Hello");
@@ -17,7 +17,7 @@ error: using `write!()` with a format string that ends in a single newline
 LL |     write!(v, "Hello {}/n", "world");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "Hello {}/n", "world");
 LL +     writeln!(v, "Hello {}", "world");
@@ -29,7 +29,7 @@ error: using `write!()` with a format string that ends in a single newline
 LL |     write!(v, "Hello {} {}/n", "world", "#2");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "Hello {} {}/n", "world", "#2");
 LL +     writeln!(v, "Hello {} {}", "world", "#2");
@@ -41,7 +41,7 @@ error: using `write!()` with a format string that ends in a single newline
 LL |     write!(v, "{}/n", 1265);
    |     ^^^^^^^^^^^^^^^^^^^^^^^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "{}/n", 1265);
 LL +     writeln!(v, "{}", 1265);
@@ -53,7 +53,7 @@ error: using `write!()` with a format string that ends in a single newline
 LL |     write!(v, "/n");
    |     ^^^^^^^^^^^^^^^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "/n");
 LL +     writeln!(v);
@@ -65,7 +65,7 @@ error: using `write!()` with a format string that ends in a single newline
 LL |     write!(v, "//n"); // should fail
    |     ^^^^^^^^^^^^^^^^^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "//n"); // should fail
 LL +     writeln!(v, "/"); // should fail
@@ -81,11 +81,10 @@ LL | | "
 LL | |     );
    | |_____^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL ~     writeln!(
-LL |         v,
-LL ~         ""
+LL ~         v
    |
 
 error: using `write!()` with a format string that ends in a single newline
@@ -98,11 +97,10 @@ LL | | "
 LL | |     );
    | |_____^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL ~     writeln!(
-LL |         v,
-LL ~         r""
+LL ~         v
    |
 
 error: using `write!()` with a format string that ends in a single newline
@@ -111,23 +109,11 @@ error: using `write!()` with a format string that ends in a single newline
 LL |     write!(v, "/r/n"); //~ ERROR
    |     ^^^^^^^^^^^^^^^^^^
    |
-help: use `writeln!()` instead
+help: use `writeln!` instead
    |
 LL -     write!(v, "/r/n"); //~ ERROR
 LL +     writeln!(v, "/r"); //~ ERROR
    |
 
-error: using `write!()` with a format string that ends in a single newline
-  --> $DIR/write_with_newline.rs:58:5
-   |
-LL |     write!(v, "foo/rbar/n");
-   |     ^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: use `writeln!()` instead
-   |
-LL -     write!(v, "foo/rbar/n");
-LL +     writeln!(v, "foo/rbar");
-   |
-
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
diff --git a/src/tools/clippy/tests/ui/writeln_empty_string.stderr b/src/tools/clippy/tests/ui/writeln_empty_string.stderr
index ac65aadfc0e8..25e69ec48e7e 100644
--- a/src/tools/clippy/tests/ui/writeln_empty_string.stderr
+++ b/src/tools/clippy/tests/ui/writeln_empty_string.stderr
@@ -1,16 +1,20 @@
-error: using `writeln!(v, "")`
+error: empty string literal in `writeln!`
   --> $DIR/writeln_empty_string.rs:11:5
    |
 LL |     writeln!(v, "");
-   |     ^^^^^^^^^^^^^^^ help: replace it with: `writeln!(v)`
+   |     ^^^^^^^^^^----^
+   |               |
+   |               help: remove the empty string
    |
    = note: `-D clippy::writeln-empty-string` implied by `-D warnings`
 
-error: using `writeln!(suggestion, "")`
+error: empty string literal in `writeln!`
   --> $DIR/writeln_empty_string.rs:14:5
    |
 LL |     writeln!(suggestion, "");
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `writeln!(suggestion)`
+   |     ^^^^^^^^^^^^^^^^^^^----^
+   |                        |
+   |                        help: remove the empty string
 
 error: aborting due to 2 previous errors
 
diff --git a/src/tools/clippy/tests/workspace.rs b/src/tools/clippy/tests/workspace.rs
index e13efb3e0164..95325e060378 100644
--- a/src/tools/clippy/tests/workspace.rs
+++ b/src/tools/clippy/tests/workspace.rs
@@ -20,8 +20,8 @@ fn test_no_deps_ignores_path_deps_in_workspaces() {
         .current_dir(&cwd)
         .env("CARGO_TARGET_DIR", &target_dir)
         .arg("clean")
-        .args(&["-p", "subcrate"])
-        .args(&["-p", "path_dep"])
+        .args(["-p", "subcrate"])
+        .args(["-p", "path_dep"])
         .output()
         .unwrap();
 
@@ -32,11 +32,11 @@ fn test_no_deps_ignores_path_deps_in_workspaces() {
         .env("CARGO_INCREMENTAL", "0")
         .env("CARGO_TARGET_DIR", &target_dir)
         .arg("clippy")
-        .args(&["-p", "subcrate"])
+        .args(["-p", "subcrate"])
         .arg("--no-deps")
         .arg("--")
         .arg("-Cdebuginfo=0") // disable debuginfo to generate less data in the target dir
-        .args(&["--cfg", r#"feature="primary_package_test""#])
+        .args(["--cfg", r#"feature="primary_package_test""#])
         .output()
         .unwrap();
     println!("status: {}", output.status);
@@ -52,10 +52,10 @@ fn test_no_deps_ignores_path_deps_in_workspaces() {
             .env("CARGO_INCREMENTAL", "0")
             .env("CARGO_TARGET_DIR", &target_dir)
             .arg("clippy")
-            .args(&["-p", "subcrate"])
+            .args(["-p", "subcrate"])
             .arg("--")
             .arg("-Cdebuginfo=0") // disable debuginfo to generate less data in the target dir
-            .args(&["--cfg", r#"feature="primary_package_test""#])
+            .args(["--cfg", r#"feature="primary_package_test""#])
             .output()
             .unwrap();
         println!("status: {}", output.status);
@@ -79,7 +79,7 @@ fn test_no_deps_ignores_path_deps_in_workspaces() {
             .env("CARGO_INCREMENTAL", "0")
             .env("CARGO_TARGET_DIR", &target_dir)
             .arg("clippy")
-            .args(&["-p", "subcrate"])
+            .args(["-p", "subcrate"])
             .arg("--")
             .arg("-Cdebuginfo=0") // disable debuginfo to generate less data in the target dir
             .output()
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 6f17b9e1be9a..4994fb9bbf94 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -203,6 +203,9 @@ pub struct Config {
     /// The jsondocck executable.
     pub jsondocck_path: Option<String>,
 
+    /// The jsondoclint executable.
+    pub jsondoclint_path: Option<String>,
+
     /// The LLVM `FileCheck` binary path.
     pub llvm_filecheck: Option<PathBuf>,
 
@@ -275,10 +278,6 @@ pub struct Config {
     /// override this setting.
     pub optimize_tests: bool,
 
-    /// What panic strategy the target is built with.  Unwind supports Abort, but
-    /// not vice versa.
-    pub target_panic: PanicStrategy,
-
     /// Target system to be tested
     pub target: String,
 
@@ -423,6 +422,10 @@ impl Config {
         *&self.target_cfg().pointer_width
     }
 
+    pub fn can_unwind(&self) -> bool {
+        self.target_cfg().panic == PanicStrategy::Unwind
+    }
+
     pub fn has_asm_support(&self) -> bool {
         static ASM_SUPPORTED_ARCHS: &[&str] = &[
             "x86", "x86_64", "arm", "aarch64", "riscv32",
@@ -443,6 +446,7 @@ pub struct TargetCfg {
     families: Vec<String>,
     pointer_width: u32,
     endian: Endian,
+    panic: PanicStrategy,
 }
 
 #[derive(Eq, PartialEq, Clone, Debug)]
@@ -478,6 +482,7 @@ impl TargetCfg {
         let mut families = Vec::new();
         let mut pointer_width = None;
         let mut endian = None;
+        let mut panic = None;
         for line in print_cfg.lines() {
             if let Some((name, value)) = line.split_once('=') {
                 let value = value.trim_matches('"');
@@ -495,6 +500,13 @@ impl TargetCfg {
                             s => panic!("unexpected {s}"),
                         })
                     }
+                    "panic" => {
+                        panic = match value {
+                            "abort" => Some(PanicStrategy::Abort),
+                            "unwind" => Some(PanicStrategy::Unwind),
+                            s => panic!("unexpected {s}"),
+                        }
+                    }
                     _ => {}
                 }
             }
@@ -507,6 +519,7 @@ impl TargetCfg {
             families,
             pointer_width: pointer_width.unwrap(),
             endian: endian.unwrap(),
+            panic: panic.unwrap(),
         }
     }
 }
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 8f097f47b451..6f8522750036 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -7,7 +7,7 @@ use std::path::{Path, PathBuf};
 
 use tracing::*;
 
-use crate::common::{CompareMode, Config, Debugger, FailMode, Mode, PanicStrategy, PassMode};
+use crate::common::{CompareMode, Config, Debugger, FailMode, Mode, PassMode};
 use crate::util;
 use crate::{extract_cdb_version, extract_gdb_version};
 
@@ -897,15 +897,27 @@ pub fn make_test_description<R: Read>(
     let has_hwasan = util::HWASAN_SUPPORTED_TARGETS.contains(&&*config.target);
     let has_memtag = util::MEMTAG_SUPPORTED_TARGETS.contains(&&*config.target);
     let has_shadow_call_stack = util::SHADOWCALLSTACK_SUPPORTED_TARGETS.contains(&&*config.target);
-    // for `-Z gcc-ld=lld`
+
+    // For tests using the `needs-rust-lld` directive (e.g. for `-Zgcc-ld=lld`), we need to find
+    // whether `rust-lld` is present in the compiler under test.
+    //
+    // The --compile-lib-path is the path to host shared libraries, but depends on the OS. For
+    // example:
+    // - on linux, it can be <sysroot>/lib
+    // - on windows, it can be <sysroot>/bin
+    //
+    // However, `rust-lld` is only located under the lib path, so we look for it there.
     let has_rust_lld = config
         .compile_lib_path
+        .parent()
+        .expect("couldn't traverse to the parent of the specified --compile-lib-path")
+        .join("lib")
         .join("rustlib")
         .join(&config.target)
         .join("bin")
-        .join("gcc-ld")
-        .join(if config.host.contains("windows") { "ld.exe" } else { "ld" })
+        .join(if config.host.contains("windows") { "rust-lld.exe" } else { "rust-lld" })
         .exists();
+
     iter_header(path, src, &mut |revision, ln| {
         if revision.is_some() && revision != cfg {
             return;
@@ -937,8 +949,7 @@ pub fn make_test_description<R: Read>(
         ignore |= !has_memtag && config.parse_name_directive(ln, "needs-sanitizer-memtag");
         ignore |= !has_shadow_call_stack
             && config.parse_name_directive(ln, "needs-sanitizer-shadow-call-stack");
-        ignore |= config.target_panic == PanicStrategy::Abort
-            && config.parse_name_directive(ln, "needs-unwind");
+        ignore |= !config.can_unwind() && config.parse_name_directive(ln, "needs-unwind");
         ignore |= config.target == "wasm32-unknown-unknown"
             && config.parse_name_directive(ln, directives::CHECK_RUN_RESULTS);
         ignore |= config.debugger == Some(Debugger::Cdb) && ignore_cdb(config, ln);
diff --git a/src/tools/compiletest/src/main.rs b/src/tools/compiletest/src/main.rs
index 0e2cc52a645b..dccfd4e0d980 100644
--- a/src/tools/compiletest/src/main.rs
+++ b/src/tools/compiletest/src/main.rs
@@ -5,9 +5,7 @@
 
 extern crate test;
 
-use crate::common::{
-    expected_output_path, output_base_dir, output_relative_path, PanicStrategy, UI_EXTENSIONS,
-};
+use crate::common::{expected_output_path, output_base_dir, output_relative_path, UI_EXTENSIONS};
 use crate::common::{CompareMode, Config, Debugger, Mode, PassMode, TestPaths};
 use crate::util::logv;
 use getopts::Options;
@@ -64,6 +62,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         .optopt("", "rust-demangler-path", "path to rust-demangler to use in tests", "PATH")
         .reqopt("", "python", "path to python to use for doc tests", "PATH")
         .optopt("", "jsondocck-path", "path to jsondocck to use for doc tests", "PATH")
+        .optopt("", "jsondoclint-path", "path to jsondoclint to use for doc tests", "PATH")
         .optopt("", "valgrind-path", "path to Valgrind executable for Valgrind tests", "PROGRAM")
         .optflag("", "force-valgrind", "fail if Valgrind tests cannot be run under Valgrind")
         .optopt("", "run-clang-based-tests-with", "path to Clang executable", "PATH")
@@ -104,7 +103,6 @@ pub fn parse_config(args: Vec<String>) -> Config {
         .optmulti("", "host-rustcflags", "flags to pass to rustc for host", "FLAGS")
         .optmulti("", "target-rustcflags", "flags to pass to rustc for target", "FLAGS")
         .optflag("", "optimize-tests", "run tests with optimizations enabled")
-        .optopt("", "target-panic", "what panic strategy the target supports", "unwind | abort")
         .optflag("", "verbose", "run tests verbosely, showing all output")
         .optflag(
             "",
@@ -226,6 +224,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         rust_demangler_path: matches.opt_str("rust-demangler-path").map(PathBuf::from),
         python: matches.opt_str("python").unwrap(),
         jsondocck_path: matches.opt_str("jsondocck-path"),
+        jsondoclint_path: matches.opt_str("jsondoclint-path"),
         valgrind_path: matches.opt_str("valgrind-path"),
         force_valgrind: matches.opt_present("force-valgrind"),
         run_clang_based_tests_with: matches.opt_str("run-clang-based-tests-with"),
@@ -256,11 +255,6 @@ pub fn parse_config(args: Vec<String>) -> Config {
         host_rustcflags: Some(matches.opt_strs("host-rustcflags").join(" ")),
         target_rustcflags: Some(matches.opt_strs("target-rustcflags").join(" ")),
         optimize_tests: matches.opt_present("optimize-tests"),
-        target_panic: match matches.opt_str("target-panic").as_deref() {
-            Some("unwind") | None => PanicStrategy::Unwind,
-            Some("abort") => PanicStrategy::Abort,
-            _ => panic!("unknown `--target-panic` option `{}` given", mode),
-        },
         target,
         host: opt_str2(matches.opt_str("host")),
         cdb,
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 11d0798d553a..8f289876f730 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -2563,14 +2563,13 @@ impl<'test> TestCx<'test> {
 
         let mut json_out = out_dir.join(self.testpaths.file.file_stem().unwrap());
         json_out.set_extension("json");
+
         let res = self.cmd2procres(
-            Command::new(&self.config.python)
-                .arg(root.join("src/etc/check_missing_items.py"))
-                .arg(&json_out),
+            Command::new(self.config.jsondoclint_path.as_ref().unwrap()).arg(&json_out),
         );
 
         if !res.status.success() {
-            self.fatal_proc_rec("check_missing_items failed!", &res);
+            self.fatal_proc_rec("jsondoclint failed!", &res);
         }
     }
 
@@ -2594,7 +2593,7 @@ impl<'test> TestCx<'test> {
                     }
                     None
                 } else {
-                    let sline = line.split("///").last().unwrap_or("");
+                    let sline = line.rsplit("///").next().unwrap();
                     let line = sline.trim_start();
                     if line.starts_with("```") {
                         if ignore {
diff --git a/src/tools/compiletest/src/util.rs b/src/tools/compiletest/src/util.rs
index 9d047b63c859..e5ff0906be8a 100644
--- a/src/tools/compiletest/src/util.rs
+++ b/src/tools/compiletest/src/util.rs
@@ -11,9 +11,15 @@ mod tests;
 pub const ASAN_SUPPORTED_TARGETS: &[&str] = &[
     "aarch64-apple-darwin",
     "aarch64-fuchsia",
+    "aarch64-linux-android",
     "aarch64-unknown-linux-gnu",
+    "arm-linux-androideabi",
+    "armv7-linux-androideabi",
+    "i686-linux-android",
+    "i686-unknown-linux-gnu",
     "x86_64-apple-darwin",
     "x86_64-fuchsia",
+    "x86_64-linux-android",
     "x86_64-unknown-freebsd",
     "x86_64-unknown-linux-gnu",
 ];
diff --git a/src/tools/error_index_generator/Cargo.toml b/src/tools/error_index_generator/Cargo.toml
index b9fd852f742c..f4dac6e947e3 100644
--- a/src/tools/error_index_generator/Cargo.toml
+++ b/src/tools/error_index_generator/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
-rustdoc = { path = "../../librustdoc" }
+mdbook = { version = "0.4", default-features = false, features = ["search"] }
 
 [[bin]]
 name = "error_index_generator"
diff --git a/src/tools/error_index_generator/book_config.toml b/src/tools/error_index_generator/book_config.toml
new file mode 100644
index 000000000000..885100ae3a44
--- /dev/null
+++ b/src/tools/error_index_generator/book_config.toml
@@ -0,0 +1,19 @@
+[book]
+title = "Error codes index"
+description = "Book listing all Rust error codes"
+src = ""
+
+[output.html]
+git-repository-url = "https://github.com/rust-lang/rust/"
+additional-css = ["error-index.css"]
+additional-js = ["error-index.js"]
+
+[output.html.search]
+enable = true
+limit-results = 20
+use-boolean-and = true
+boost-title = 2
+boost-hierarchy = 2
+boost-paragraph = 1
+expand = true
+heading-split-level = 0
diff --git a/src/tools/error_index_generator/error-index.css b/src/tools/error_index_generator/error-index.css
new file mode 100644
index 000000000000..dcac2e18efe6
--- /dev/null
+++ b/src/tools/error_index_generator/error-index.css
@@ -0,0 +1,39 @@
+code.compile_fail {
+	border-left: 2px solid red;
+}
+
+pre .tooltip {
+	position: absolute;
+	left: -25px;
+	top: 0;
+	z-index: 1;
+	color: red;
+	cursor: pointer;
+}
+pre .tooltip::after {
+	display: none;
+	content: "This example deliberately fails to compile";
+	background-color: #000;
+	color: #fff;
+	border-color: #000;
+	text-align: center;
+	padding: 5px 3px 3px 3px;
+	border-radius: 6px;
+	margin-left: 5px;
+}
+pre .tooltip::before {
+	display: none;
+	border-color: transparent black transparent transparent;
+	content: " ";
+	position: absolute;
+	top: 50%;
+	left: 2px;
+	margin-top: -5px;
+	border-width: 5px;
+	border-style: solid;
+	height: 0px;
+}
+
+pre .tooltip:hover::before, pre .tooltip:hover::after {
+	display: inline;
+}
diff --git a/src/tools/error_index_generator/error-index.js b/src/tools/error_index_generator/error-index.js
new file mode 100644
index 000000000000..39b371be04b9
--- /dev/null
+++ b/src/tools/error_index_generator/error-index.js
@@ -0,0 +1,9 @@
+for (const elem of document.querySelectorAll("pre.playground")) {
+    if (elem.querySelector(".compile_fail") === null) {
+        continue;
+    }
+    const child = document.createElement("div");
+    child.className = "tooltip";
+    child.textContent = "ⓘ";
+    elem.appendChild(child);
+}
diff --git a/src/tools/error_index_generator/main.rs b/src/tools/error_index_generator/main.rs
index 68c46700361a..1bde8e007826 100644
--- a/src/tools/error_index_generator/main.rs
+++ b/src/tools/error_index_generator/main.rs
@@ -1,20 +1,21 @@
 #![feature(rustc_private)]
 
 extern crate rustc_driver;
-extern crate rustc_span;
 
+// We use the function we generate from `register_diagnostics!`.
 use crate::error_codes::error_codes;
 
 use std::env;
 use std::error::Error;
-use std::fs::{create_dir_all, File};
+use std::fs::{self, File};
 use std::io::Write;
 use std::path::Path;
 use std::path::PathBuf;
 
-use rustc_span::edition::DEFAULT_EDITION;
+use std::str::FromStr;
 
-use rustdoc::html::markdown::{ErrorCodes, HeadingOffset, IdMap, Markdown, Playground};
+use mdbook::book::{parse_summary, BookItem, Chapter};
+use mdbook::{Config, MDBook};
 
 macro_rules! register_diagnostics {
     ($($error_code:ident: $message:expr,)+ ; $($undocumented:ident,)* ) => {
@@ -33,104 +34,21 @@ macro_rules! register_diagnostics {
 mod error_codes;
 
 enum OutputFormat {
-    HTML(HTMLFormatter),
+    HTML,
     Markdown,
     Unknown(String),
 }
 
 impl OutputFormat {
-    fn from(format: &str, resource_suffix: &str) -> OutputFormat {
+    fn from(format: &str) -> OutputFormat {
         match &*format.to_lowercase() {
-            "html" => OutputFormat::HTML(HTMLFormatter(resource_suffix.to_owned())),
+            "html" => OutputFormat::HTML,
             "markdown" => OutputFormat::Markdown,
             s => OutputFormat::Unknown(s.to_owned()),
         }
     }
 }
 
-struct HTMLFormatter(String);
-
-impl HTMLFormatter {
-    fn create_error_code_file(
-        &self,
-        err_code: &str,
-        explanation: &str,
-        parent_dir: &Path,
-    ) -> Result<(), Box<dyn Error>> {
-        let mut output_file = File::create(parent_dir.join(err_code).with_extension("html"))?;
-
-        self.header(&mut output_file, "../", "")?;
-        self.title(&mut output_file, &format!("Error code {}", err_code))?;
-
-        let mut id_map = IdMap::new();
-        let playground =
-            Playground { crate_name: None, url: String::from("https://play.rust-lang.org/") };
-        write!(
-            output_file,
-            "{}",
-            Markdown {
-                content: explanation,
-                links: &[],
-                ids: &mut id_map,
-                error_codes: ErrorCodes::Yes,
-                edition: DEFAULT_EDITION,
-                playground: &Some(playground),
-                heading_offset: HeadingOffset::H1,
-            }
-            .into_string()
-        )?;
-        write!(
-            output_file,
-            "<p>\
-                <a style='text-align: center;display: block;width: 100%;' \
-                   href='../error-index.html'>Back to list of error codes</a>\
-             </p>",
-        )?;
-
-        self.footer(&mut output_file)
-    }
-
-    fn header(
-        &self,
-        output: &mut dyn Write,
-        extra_path: &str,
-        extra: &str,
-    ) -> Result<(), Box<dyn Error>> {
-        write!(
-            output,
-            r##"<!DOCTYPE html>
-<html>
-<head>
-<title>Rust Compiler Error Index</title>
-<meta charset="utf-8">
-<!-- Include rust.css after light.css so its rules take priority. -->
-<link rel="stylesheet" type="text/css" href="{extra_path}rustdoc{suffix}.css"/>
-<link rel="stylesheet" type="text/css" href="{extra_path}light{suffix}.css"/>
-<link rel="stylesheet" type="text/css" href="{extra_path}rust.css"/>
-<style>
-.error-undescribed {{
-    display: none;
-}}
-</style>{extra}
-</head>
-<body>
-"##,
-            suffix = self.0,
-        )?;
-        Ok(())
-    }
-
-    fn title(&self, output: &mut dyn Write, title: &str) -> Result<(), Box<dyn Error>> {
-        write!(output, "<h1>{}</h1>\n", title)?;
-        Ok(())
-    }
-
-    fn footer(&self, output: &mut dyn Write) -> Result<(), Box<dyn Error>> {
-        write!(output, "</body></html>")?;
-        Ok(())
-    }
-}
-
 /// Output an HTML page for the errors in `err_map` to `output_path`.
 fn render_markdown(output_path: &Path) -> Result<(), Box<dyn Error>> {
     let mut output_file = File::create(output_path)?;
@@ -147,61 +65,119 @@ fn render_markdown(output_path: &Path) -> Result<(), Box<dyn Error>> {
     Ok(())
 }
 
-fn render_html(output_path: &Path, formatter: HTMLFormatter) -> Result<(), Box<dyn Error>> {
-    let mut output_file = File::create(output_path)?;
+// By default, mdbook doesn't consider code blocks as Rust ones contrary to rustdoc so we have
+// to manually add `rust` attribute whenever needed.
+fn add_rust_attribute_on_codeblock(explanation: &str) -> String {
+    // Very hacky way to add the rust attribute on all code blocks.
+    let mut skip = true;
+    explanation.split("\n```").fold(String::new(), |mut acc, part| {
+        if !acc.is_empty() {
+            acc.push_str("\n```");
+        }
+        if !skip {
+            if let Some(attrs) = part.split('\n').next() {
+                if !attrs.contains("rust")
+                    && (attrs.is_empty()
+                        || attrs.contains("compile_fail")
+                        || attrs.contains("ignore")
+                        || attrs.contains("edition"))
+                {
+                    if !attrs.is_empty() {
+                        acc.push_str("rust,");
+                    } else {
+                        acc.push_str("rust");
+                    }
+                }
+            }
+        }
+        skip = !skip;
+        acc.push_str(part);
+        acc
+    })
+}
 
-    let error_codes_dir = "error_codes";
+fn render_html(output_path: &Path) -> Result<(), Box<dyn Error>> {
+    let mut introduction = format!(
+        "<script src='redirect.js'></script>
+# Rust error codes index
 
-    let parent = output_path.parent().expect("There should have a parent").join(error_codes_dir);
+This page lists all the error codes emitted by the Rust compiler.
 
-    if !parent.exists() {
-        create_dir_all(&parent)?;
-    }
+"
+    );
 
-    formatter.header(
-        &mut output_file,
-        "",
-        &format!(
-            r#"<script>(function() {{
-    if (window.location.hash) {{
-        let code = window.location.hash.replace(/^#/, '');
-        // We have to make sure this pattern matches to avoid inadvertently creating an
-        // open redirect.
-        if (/^E[0-9]+$/.test(code)) {{
-            window.location = './{error_codes_dir}/' + code + '.html';
-        }}
-    }}
-}})()</script>"#
-        ),
-    )?;
-    formatter.title(&mut output_file, "Rust Compiler Error Index")?;
+    let err_codes = error_codes();
+    let mut chapters = Vec::with_capacity(err_codes.len());
 
-    write!(
-        output_file,
-        "<p>This page lists all the error codes emitted by the Rust compiler. If you want a full \
-            explanation on an error code, click on it.</p>\
-         <ul>",
-    )?;
-    for (err_code, explanation) in error_codes().iter() {
+    for (err_code, explanation) in err_codes.iter() {
         if let Some(explanation) = explanation {
-            write!(
-                output_file,
-                "<li><a href='./{0}/{1}.html'>{1}</a></li>",
-                error_codes_dir, err_code
-            )?;
-            formatter.create_error_code_file(err_code, explanation, &parent)?;
+            introduction.push_str(&format!(" * [{0}](./{0}.html)\n", err_code));
+
+            let content = add_rust_attribute_on_codeblock(explanation);
+            chapters.push(BookItem::Chapter(Chapter {
+                name: err_code.to_string(),
+                content: format!("# Error code {}\n\n{}\n", err_code, content),
+                number: None,
+                sub_items: Vec::new(),
+                // We generate it into the `error_codes` folder.
+                path: Some(PathBuf::from(&format!("{}.html", err_code))),
+                source_path: None,
+                parent_names: Vec::new(),
+            }));
         } else {
-            write!(output_file, "<li>{}</li>", err_code)?;
+            introduction.push_str(&format!(" * {}\n", err_code));
         }
     }
-    write!(output_file, "</ul>")?;
-    formatter.footer(&mut output_file)
+
+    let mut config = Config::from_str(include_str!("book_config.toml"))?;
+    config.build.build_dir = output_path.join("error_codes").to_path_buf();
+    let mut book = MDBook::load_with_config_and_summary(
+        env!("CARGO_MANIFEST_DIR"),
+        config,
+        parse_summary("")?,
+    )?;
+    let chapter = Chapter {
+        name: "Rust error codes index".to_owned(),
+        content: introduction,
+        number: None,
+        sub_items: chapters,
+        // Very important: this file is named as `error-index.html` and not `index.html`!
+        path: Some(PathBuf::from("error-index.html")),
+        source_path: None,
+        parent_names: Vec::new(),
+    };
+    book.book.sections.push(BookItem::Chapter(chapter));
+    book.build()?;
+
+    // We can't put this content into another file, otherwise `mbdbook` will also put it into the
+    // output directory, making a duplicate.
+    fs::write(
+        output_path.join("error-index.html"),
+        r#"<!DOCTYPE html>
+<html>
+    <head>
+        <title>Rust error codes index - Error codes index</title>
+        <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
+        <meta name="description" content="Book listing all Rust error codes">
+        <script src="error_codes/redirect.js"></script>
+    </head>
+    <body>
+        <div>If you are not automatically redirected to the error code index, please <a id="index-link" href="./error_codes/error-index.html">here</a>.
+        <script>document.getElementById("index-link").click()</script>
+    </body>
+</html>"#,
+    )?;
+
+    // No need for a 404 file, it's already handled by the server.
+    fs::remove_file(output_path.join("error_codes/404.html"))?;
+
+    Ok(())
 }
 
 fn main_with_result(format: OutputFormat, dst: &Path) -> Result<(), Box<dyn Error>> {
     match format {
         OutputFormat::Unknown(s) => panic!("Unknown output format: {}", s),
-        OutputFormat::HTML(h) => render_html(dst, h),
+        OutputFormat::HTML => render_html(dst),
         OutputFormat::Markdown => render_markdown(dst),
     }
 }
@@ -210,12 +186,9 @@ fn parse_args() -> (OutputFormat, PathBuf) {
     let mut args = env::args().skip(1);
     let format = args.next();
     let dst = args.next();
-    let resource_suffix = args.next().unwrap_or_else(String::new);
-    let format = format
-        .map(|a| OutputFormat::from(&a, &resource_suffix))
-        .unwrap_or(OutputFormat::from("html", &resource_suffix));
+    let format = format.map(|a| OutputFormat::from(&a)).unwrap_or(OutputFormat::from("html"));
     let dst = dst.map(PathBuf::from).unwrap_or_else(|| match format {
-        OutputFormat::HTML(..) => PathBuf::from("doc/error-index.html"),
+        OutputFormat::HTML => PathBuf::from("doc"),
         OutputFormat::Markdown => PathBuf::from("doc/error-index.md"),
         OutputFormat::Unknown(..) => PathBuf::from("<nul>"),
     });
@@ -225,9 +198,8 @@ fn parse_args() -> (OutputFormat, PathBuf) {
 fn main() {
     rustc_driver::init_env_logger("RUST_LOG");
     let (format, dst) = parse_args();
-    let result =
-        rustc_span::create_default_session_globals_then(move || main_with_result(format, &dst));
+    let result = main_with_result(format, &dst);
     if let Err(e) = result {
-        panic!("{}", e.to_string());
+        panic!("{:?}", e);
     }
 }
diff --git a/src/tools/error_index_generator/redirect.js b/src/tools/error_index_generator/redirect.js
new file mode 100644
index 000000000000..8c907f5795d3
--- /dev/null
+++ b/src/tools/error_index_generator/redirect.js
@@ -0,0 +1,16 @@
+(function() {
+    if (window.location.hash) {
+        let code = window.location.hash.replace(/^#/, '');
+        // We have to make sure this pattern matches to avoid inadvertently creating an
+        // open redirect.
+        if (!/^E[0-9]+$/.test(code)) {
+            return;
+        }
+        if (window.location.pathname.indexOf("/error_codes/") !== -1) {
+            // We're not at the top level, so we don't prepend with "./error_codes/".
+            window.location = './' + code + '.html';
+        } else {
+            window.location = './error_codes/' + code + '.html';
+        }
+    }
+})()
diff --git a/src/tools/jsondoclint/Cargo.toml b/src/tools/jsondoclint/Cargo.toml
new file mode 100644
index 000000000000..84a6c7f96c46
--- /dev/null
+++ b/src/tools/jsondoclint/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "jsondoclint"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0.62"
+fs-err = "2.8.1"
+rustdoc-json-types = { version = "0.1.0", path = "../../rustdoc-json-types" }
+serde_json = "1.0.85"
diff --git a/src/tools/jsondoclint/src/item_kind.rs b/src/tools/jsondoclint/src/item_kind.rs
new file mode 100644
index 000000000000..ad8e96a0bd81
--- /dev/null
+++ b/src/tools/jsondoclint/src/item_kind.rs
@@ -0,0 +1,184 @@
+use rustdoc_json_types::{Item, ItemEnum, ItemKind, ItemSummary};
+
+/// A univeral way to represent an [`ItemEnum`] or [`ItemKind`]
+#[derive(Debug)]
+pub(crate) enum Kind {
+    Module,
+    ExternCrate,
+    Import,
+    Struct,
+    StructField,
+    Union,
+    Enum,
+    Variant,
+    Function,
+    Typedef,
+    OpaqueTy,
+    Constant,
+    Trait,
+    TraitAlias,
+    Method,
+    Impl,
+    Static,
+    ForeignType,
+    Macro,
+    ProcAttribute,
+    ProcDerive,
+    AssocConst,
+    AssocType,
+    Primitive,
+    Keyword,
+    // Not in ItemKind
+    ProcMacro,
+}
+
+impl Kind {
+    pub fn can_appear_in_mod(self) -> bool {
+        use Kind::*;
+        match self {
+            Module => true,
+            ExternCrate => true,
+            Import => true,
+            Union => true,
+            Struct => true,
+            Enum => true,
+            Function => true,
+            Trait => true,
+            TraitAlias => true,
+            Impl => true,
+            Typedef => true,
+            Constant => true,
+            Static => true,
+            Macro => true,
+            ProcMacro => true,
+            Primitive => true,
+            ForeignType => true,
+
+            // FIXME(adotinthevoid): I'm not sure if these are corrent
+            Keyword => false,
+            OpaqueTy => false,
+            ProcAttribute => false,
+            ProcDerive => false,
+
+            // Only in traits
+            AssocConst => false,
+            AssocType => false,
+            Method => false,
+
+            StructField => false, // Only in structs or variants
+            Variant => false,     // Only in enums
+        }
+    }
+
+    pub fn can_appear_in_trait(self) -> bool {
+        match self {
+            Kind::AssocConst => true,
+            Kind::AssocType => true,
+            Kind::Method => true,
+
+            Kind::Module => false,
+            Kind::ExternCrate => false,
+            Kind::Import => false,
+            Kind::Struct => false,
+            Kind::StructField => false,
+            Kind::Union => false,
+            Kind::Enum => false,
+            Kind::Variant => false,
+            Kind::Function => false,
+            Kind::Typedef => false,
+            Kind::OpaqueTy => false,
+            Kind::Constant => false,
+            Kind::Trait => false,
+            Kind::TraitAlias => false,
+            Kind::Impl => false,
+            Kind::Static => false,
+            Kind::ForeignType => false,
+            Kind::Macro => false,
+            Kind::ProcAttribute => false,
+            Kind::ProcDerive => false,
+            Kind::Primitive => false,
+            Kind::Keyword => false,
+            Kind::ProcMacro => false,
+        }
+    }
+
+    pub fn is_struct_field(self) -> bool {
+        matches!(self, Kind::StructField)
+    }
+    pub fn is_module(self) -> bool {
+        matches!(self, Kind::Module)
+    }
+    pub fn is_impl(self) -> bool {
+        matches!(self, Kind::Impl)
+    }
+    pub fn is_variant(self) -> bool {
+        matches!(self, Kind::Variant)
+    }
+    pub fn is_trait(self) -> bool {
+        matches!(self, Kind::Trait)
+    }
+    pub fn is_struct_enum_union(self) -> bool {
+        matches!(self, Kind::Struct | Kind::Enum | Kind::Union)
+    }
+
+    pub fn from_item(i: &Item) -> Self {
+        use Kind::*;
+        match i.inner {
+            ItemEnum::Module(_) => Module,
+            ItemEnum::Import(_) => Import,
+            ItemEnum::Union(_) => Union,
+            ItemEnum::Struct(_) => Struct,
+            ItemEnum::StructField(_) => StructField,
+            ItemEnum::Enum(_) => Enum,
+            ItemEnum::Variant(_) => Variant,
+            ItemEnum::Function(_) => Function,
+            ItemEnum::Trait(_) => Trait,
+            ItemEnum::TraitAlias(_) => TraitAlias,
+            ItemEnum::Method(_) => Method,
+            ItemEnum::Impl(_) => Impl,
+            ItemEnum::Typedef(_) => Typedef,
+            ItemEnum::OpaqueTy(_) => OpaqueTy,
+            ItemEnum::Constant(_) => Constant,
+            ItemEnum::Static(_) => Static,
+            ItemEnum::Macro(_) => Macro,
+            ItemEnum::ProcMacro(_) => ProcMacro,
+            // https://github.com/rust-lang/rust/issues/100961
+            ItemEnum::PrimitiveType(_) => Primitive,
+            ItemEnum::ForeignType => ForeignType,
+            ItemEnum::ExternCrate { .. } => ExternCrate,
+            ItemEnum::AssocConst { .. } => AssocConst,
+            ItemEnum::AssocType { .. } => AssocType,
+        }
+    }
+
+    pub fn from_summary(s: &ItemSummary) -> Self {
+        use Kind::*;
+        match s.kind {
+            ItemKind::AssocConst => AssocConst,
+            ItemKind::AssocType => AssocType,
+            ItemKind::Constant => Constant,
+            ItemKind::Enum => Enum,
+            ItemKind::ExternCrate => ExternCrate,
+            ItemKind::ForeignType => ForeignType,
+            ItemKind::Function => Function,
+            ItemKind::Impl => Impl,
+            ItemKind::Import => Import,
+            ItemKind::Keyword => Keyword,
+            ItemKind::Macro => Macro,
+            ItemKind::Method => Method,
+            ItemKind::Module => Module,
+            ItemKind::OpaqueTy => OpaqueTy,
+            ItemKind::Primitive => Primitive,
+            ItemKind::ProcAttribute => ProcAttribute,
+            ItemKind::ProcDerive => ProcDerive,
+            ItemKind::Static => Static,
+            ItemKind::Struct => Struct,
+            ItemKind::StructField => StructField,
+            ItemKind::Trait => Trait,
+            ItemKind::TraitAlias => TraitAlias,
+            ItemKind::Typedef => Typedef,
+            ItemKind::Union => Union,
+            ItemKind::Variant => Variant,
+        }
+    }
+}
diff --git a/src/tools/jsondoclint/src/json_find.rs b/src/tools/jsondoclint/src/json_find.rs
new file mode 100644
index 000000000000..95ea8866609d
--- /dev/null
+++ b/src/tools/jsondoclint/src/json_find.rs
@@ -0,0 +1,74 @@
+use std::fmt::Write;
+
+use serde_json::Value;
+
+#[derive(Debug, Clone)]
+pub enum SelectorPart {
+    Field(String),
+    Index(usize),
+}
+
+pub type Selector = Vec<SelectorPart>;
+
+pub fn to_jsonpath(sel: &Selector) -> String {
+    let mut s = String::from("$");
+    for part in sel {
+        match part {
+            SelectorPart::Field(name) => {
+                if is_jsonpath_safe(name) {
+                    write!(&mut s, ".{}", name).unwrap();
+                } else {
+                    // This is probably wrong in edge cases, but all Id's are
+                    // just ascii alphanumerics, `-` `_`, and `:`
+                    write!(&mut s, "[{name:?}]").unwrap();
+                }
+            }
+            SelectorPart::Index(idx) => write!(&mut s, "[{idx}]").unwrap(),
+        }
+    }
+    s
+}
+
+fn is_jsonpath_safe(s: &str) -> bool {
+    s.chars().all(|c| c.is_ascii_alphanumeric() || c == '_')
+}
+
+pub fn find_selector(haystack: &Value, needle: &Value) -> Vec<Selector> {
+    let mut result = Vec::new();
+    let mut sel = Selector::new();
+    find_selector_recursive(haystack, needle, &mut result, &mut sel);
+    result
+}
+
+fn find_selector_recursive(
+    haystack: &Value,
+    needle: &Value,
+    result: &mut Vec<Selector>,
+    pos: &mut Selector,
+) {
+    if needle == haystack {
+        result.push(pos.clone());
+        // Haystack cant both contain needle and be needle
+    } else {
+        match haystack {
+            Value::Null => {}
+            Value::Bool(_) => {}
+            Value::Number(_) => {}
+            Value::String(_) => {}
+            Value::Array(arr) => {
+                for (idx, subhaystack) in arr.iter().enumerate() {
+                    pos.push(SelectorPart::Index(idx));
+                    find_selector_recursive(subhaystack, needle, result, pos);
+                    pos.pop().unwrap();
+                }
+            }
+            Value::Object(obj) => {
+                for (key, subhaystack) in obj {
+                    pos.push(SelectorPart::Field(key.clone()));
+                    find_selector_recursive(subhaystack, needle, result, pos);
+                    pos.pop().unwrap();
+                }
+            }
+        }
+    }
+}
diff --git a/src/tools/jsondoclint/src/main.rs b/src/tools/jsondoclint/src/main.rs
new file mode 100644
index 000000000000..70d7a82a5760
--- /dev/null
+++ b/src/tools/jsondoclint/src/main.rs
@@ -0,0 +1,64 @@
+use std::env;
+
+use anyhow::{anyhow, bail, Result};
+use fs_err as fs;
+use rustdoc_json_types::{Crate, Id, FORMAT_VERSION};
+use serde_json::Value;
+
+pub(crate) mod item_kind;
+mod json_find;
+mod validator;
+
+#[derive(Debug)]
+struct Error {
+    kind: ErrorKind,
+    id: Id,
+}
+
+#[derive(Debug)]
+enum ErrorKind {
+    NotFound,
+    Custom(String),
+}
+
+fn main() -> Result<()> {
+    let path = env::args().nth(1).ok_or_else(|| anyhow!("no path given"))?;
+    let contents = fs::read_to_string(&path)?;
+    let krate: Crate = serde_json::from_str(&contents)?;
+    assert_eq!(krate.format_version, FORMAT_VERSION);
+
+    let mut validator = validator::Validator::new(&krate);
+    validator.check_crate();
+
+    if !validator.errs.is_empty() {
+        for err in validator.errs {
+            match err.kind {
+                ErrorKind::NotFound => {
+                    let krate_json: Value = serde_json::from_str(&contents)?;
+
+                    let sels =
+                        json_find::find_selector(&krate_json, &Value::String(err.id.0.clone()));
+                    match &sels[..] {
+                        [] => unreachable!(
+                            "id must be in crate, or it wouldn't be reported as not found"
+                        ),
+                        [sel] => eprintln!(
+                            "{} not in index or paths, but refered to at '{}'",
+                            err.id.0,
+                            json_find::to_jsonpath(&sel)
+                        ),
+                        [sel, ..] => eprintln!(
+                            "{} not in index or paths, but refered to at '{}' and more",
+                            err.id.0,
+                            json_find::to_jsonpath(&sel)
+                        ),
+                    }
+                }
+                ErrorKind::Custom(msg) => eprintln!("{}: {}", err.id.0, msg),
+            }
+        }
+        bail!("Errors validating json {path}");
+    }
+
+    Ok(())
+}
diff --git a/src/tools/jsondoclint/src/validator.rs b/src/tools/jsondoclint/src/validator.rs
new file mode 100644
index 000000000000..a0e77127dc2c
--- /dev/null
+++ b/src/tools/jsondoclint/src/validator.rs
@@ -0,0 +1,442 @@
+use std::collections::HashSet;
+use std::hash::Hash;
+
+use rustdoc_json_types::{
+    Constant, Crate, DynTrait, Enum, FnDecl, Function, FunctionPointer, GenericArg, GenericArgs,
+    GenericBound, GenericParamDef, Generics, Id, Impl, Import, ItemEnum, Method, Module, OpaqueTy,
+    Path, ProcMacro, Static, Struct, StructKind, Term, Trait, TraitAlias, Type, TypeBinding,
+    TypeBindingKind, Typedef, Union, Variant, WherePredicate,
+};
+
+use crate::{item_kind::Kind, Error, ErrorKind};
+
+/// The Validator walks over the JSON tree, and ensures it is well formed.
+/// It is made of several parts.
+///
+/// - `check_*`: These take a type from [`rustdoc_json_types`], and check that
+///              it is well formed. This involves calling `check_*` functions on
+///              fields of that item, and `add_*` functions on [`Id`]s.
+/// - `add_*`: These add an [`Id`] to the worklist, after validating it to check if
+///            the `Id` is a kind expected in this suituation.
+#[derive(Debug)]
+pub struct Validator<'a> {
+    pub(crate) errs: Vec<Error>,
+    krate: &'a Crate,
+    /// Worklist of Ids to check.
+    todo: HashSet<&'a Id>,
+    /// Ids that have already been visited, so don't need to be checked again.
+    seen_ids: HashSet<&'a Id>,
+    /// Ids that have already been reported missing.
+    missing_ids: HashSet<&'a Id>,
+}
+
+enum PathKind {
+    Trait,
+    StructEnumUnion,
+}
+
+impl<'a> Validator<'a> {
+    pub fn new(krate: &'a Crate) -> Self {
+        Self {
+            krate,
+            errs: Vec::new(),
+            seen_ids: HashSet::new(),
+            todo: HashSet::new(),
+            missing_ids: HashSet::new(),
+        }
+    }
+
+    pub fn check_crate(&mut self) {
+        let root = &self.krate.root;
+        self.add_mod_id(root);
+        while let Some(id) = set_remove(&mut self.todo) {
+            self.seen_ids.insert(id);
+            self.check_item(id);
+        }
+    }
+
+    fn check_item(&mut self, id: &'a Id) {
+        if let Some(item) = &self.krate.index.get(id) {
+            match &item.inner {
+                ItemEnum::Import(x) => self.check_import(x),
+                ItemEnum::Union(x) => self.check_union(x),
+                ItemEnum::Struct(x) => self.check_struct(x),
+                ItemEnum::StructField(x) => self.check_struct_field(x),
+                ItemEnum::Enum(x) => self.check_enum(x),
+                ItemEnum::Variant(x) => self.check_variant(x, id),
+                ItemEnum::Function(x) => self.check_function(x),
+                ItemEnum::Trait(x) => self.check_trait(x),
+                ItemEnum::TraitAlias(x) => self.check_trait_alias(x),
+                ItemEnum::Method(x) => self.check_method(x),
+                ItemEnum::Impl(x) => self.check_impl(x),
+                ItemEnum::Typedef(x) => self.check_typedef(x),
+                ItemEnum::OpaqueTy(x) => self.check_opaque_ty(x),
+                ItemEnum::Constant(x) => self.check_constant(x),
+                ItemEnum::Static(x) => self.check_static(x),
+                ItemEnum::ForeignType => {} // nop
+                ItemEnum::Macro(x) => self.check_macro(x),
+                ItemEnum::ProcMacro(x) => self.check_proc_macro(x),
+                ItemEnum::PrimitiveType(x) => self.check_primitive_type(x),
+                ItemEnum::Module(x) => self.check_module(x),
+                // FIXME: Why don't these have their own structs?
+                ItemEnum::ExternCrate { .. } => {}
+                ItemEnum::AssocConst { type_, default: _ } => self.check_type(type_),
+                ItemEnum::AssocType { generics, bounds, default } => {
+                    self.check_generics(generics);
+                    bounds.iter().for_each(|b| self.check_generic_bound(b));
+                    if let Some(ty) = default {
+                        self.check_type(ty);
+                    }
+                }
+            }
+        } else {
+            assert!(self.krate.paths.contains_key(id));
+        }
+    }
+
+    // Core checkers
+    fn check_module(&mut self, module: &'a Module) {
+        module.items.iter().for_each(|i| self.add_mod_item_id(i));
+    }
+
+    fn check_import(&mut self, x: &'a Import) {
+        if x.glob {
+            self.add_mod_id(x.id.as_ref().unwrap());
+        } else if let Some(id) = &x.id {
+            self.add_mod_item_id(id);
+        }
+    }
+
+    fn check_union(&mut self, x: &'a Union) {
+        self.check_generics(&x.generics);
+        x.fields.iter().for_each(|i| self.add_field_id(i));
+        x.impls.iter().for_each(|i| self.add_impl_id(i));
+    }
+
+    fn check_struct(&mut self, x: &'a Struct) {
+        self.check_generics(&x.generics);
+        match &x.kind {
+            StructKind::Unit => {}
+            StructKind::Tuple(fields) => fields.iter().flatten().for_each(|f| self.add_field_id(f)),
+            StructKind::Plain { fields, fields_stripped: _ } => {
+                fields.iter().for_each(|f| self.add_field_id(f))
+            }
+        }
+        x.impls.iter().for_each(|i| self.add_impl_id(i));
+    }
+
+    fn check_struct_field(&mut self, x: &'a Type) {
+        self.check_type(x);
+    }
+
+    fn check_enum(&mut self, x: &'a Enum) {
+        self.check_generics(&x.generics);
+        x.variants.iter().for_each(|i| self.add_variant_id(i));
+        x.impls.iter().for_each(|i| self.add_impl_id(i));
+    }
+
+    fn check_variant(&mut self, x: &'a Variant, id: &'a Id) {
+        match x {
+            Variant::Plain(discr) => {
+                if let Some(discr) = discr {
+                    if let (Err(_), Err(_)) =
+                        (discr.value.parse::<i128>(), discr.value.parse::<u128>())
+                    {
+                        self.fail(
+                            id,
+                            ErrorKind::Custom(format!(
+                                "Failed to parse discriminant value `{}`",
+                                discr.value
+                            )),
+                        );
+                    }
+                }
+            }
+            Variant::Tuple(tys) => tys.iter().flatten().for_each(|t| self.add_field_id(t)),
+            Variant::Struct { fields, fields_stripped: _ } => {
+                fields.iter().for_each(|f| self.add_field_id(f))
+            }
+        }
+    }
+
+    fn check_function(&mut self, x: &'a Function) {
+        self.check_generics(&x.generics);
+        self.check_fn_decl(&x.decl);
+    }
+
+    fn check_trait(&mut self, x: &'a Trait) {
+        self.check_generics(&x.generics);
+        x.items.iter().for_each(|i| self.add_trait_item_id(i));
+        x.bounds.iter().for_each(|i| self.check_generic_bound(i));
+        x.implementations.iter().for_each(|i| self.add_impl_id(i));
+    }
+
+    fn check_trait_alias(&mut self, x: &'a TraitAlias) {
+        self.check_generics(&x.generics);
+        x.params.iter().for_each(|i| self.check_generic_bound(i));
+    }
+
+    fn check_method(&mut self, x: &'a Method) {
+        self.check_fn_decl(&x.decl);
+        self.check_generics(&x.generics);
+    }
+
+    fn check_impl(&mut self, x: &'a Impl) {
+        self.check_generics(&x.generics);
+        if let Some(path) = &x.trait_ {
+            self.check_path(path, PathKind::Trait);
+        }
+        self.check_type(&x.for_);
+        x.items.iter().for_each(|i| self.add_trait_item_id(i));
+        if let Some(blanket_impl) = &x.blanket_impl {
+            self.check_type(blanket_impl)
+        }
+    }
+
+    fn check_typedef(&mut self, x: &'a Typedef) {
+        self.check_generics(&x.generics);
+        self.check_type(&x.type_);
+    }
+
+    fn check_opaque_ty(&mut self, x: &'a OpaqueTy) {
+        x.bounds.iter().for_each(|b| self.check_generic_bound(b));
+        self.check_generics(&x.generics);
+    }
+
+    fn check_constant(&mut self, x: &'a Constant) {
+        self.check_type(&x.type_);
+    }
+
+    fn check_static(&mut self, x: &'a Static) {
+        self.check_type(&x.type_);
+    }
+
+    fn check_macro(&mut self, _: &'a str) {
+        // nop
+    }
+
+    fn check_proc_macro(&mut self, _: &'a ProcMacro) {
+        // nop
+    }
+
+    fn check_primitive_type(&mut self, _: &'a str) {
+        // nop
+    }
+
+    fn check_generics(&mut self, x: &'a Generics) {
+        x.params.iter().for_each(|p| self.check_generic_param_def(p));
+        x.where_predicates.iter().for_each(|w| self.check_where_predicate(w));
+    }
+
+    fn check_type(&mut self, x: &'a Type) {
+        match x {
+            Type::ResolvedPath(path) => self.check_path(path, PathKind::StructEnumUnion),
+            Type::DynTrait(dyn_trait) => self.check_dyn_trait(dyn_trait),
+            Type::Generic(_) => {}
+            Type::Primitive(_) => {}
+            Type::FunctionPointer(fp) => self.check_function_pointer(&**fp),
+            Type::Tuple(tys) => tys.iter().for_each(|ty| self.check_type(ty)),
+            Type::Slice(inner) => self.check_type(&**inner),
+            Type::Array { type_, len: _ } => self.check_type(&**type_),
+            Type::ImplTrait(bounds) => bounds.iter().for_each(|b| self.check_generic_bound(b)),
+            Type::Infer => {}
+            Type::RawPointer { mutable: _, type_ } => self.check_type(&**type_),
+            Type::BorrowedRef { lifetime: _, mutable: _, type_ } => self.check_type(&**type_),
+            Type::QualifiedPath { name: _, args, self_type, trait_ } => {
+                self.check_generic_args(&**args);
+                self.check_type(&**self_type);
+                self.check_path(trait_, PathKind::Trait);
+            }
+        }
+    }
+
+    fn check_fn_decl(&mut self, x: &'a FnDecl) {
+        x.inputs.iter().for_each(|(_name, ty)| self.check_type(ty));
+        if let Some(output) = &x.output {
+            self.check_type(output);
+        }
+    }
+
+    fn check_generic_bound(&mut self, x: &'a GenericBound) {
+        match x {
+            GenericBound::TraitBound { trait_, generic_params, modifier: _ } => {
+                self.check_path(trait_, PathKind::Trait);
+                generic_params.iter().for_each(|gpd| self.check_generic_param_def(gpd));
+            }
+            GenericBound::Outlives(_) => {}
+        }
+    }
+
+    fn check_path(&mut self, x: &'a Path, kind: PathKind) {
+        match kind {
+            PathKind::Trait => self.add_trait_id(&x.id),
+            PathKind::StructEnumUnion => self.add_struct_enum_union_id(&x.id),
+        }
+        if let Some(args) = &x.args {
+            self.check_generic_args(&**args);
+        }
+    }
+
+    fn check_generic_args(&mut self, x: &'a GenericArgs) {
+        match x {
+            GenericArgs::AngleBracketed { args, bindings } => {
+                args.iter().for_each(|arg| self.check_generic_arg(arg));
+                bindings.iter().for_each(|bind| self.check_type_binding(bind));
+            }
+            GenericArgs::Parenthesized { inputs, output } => {
+                inputs.iter().for_each(|ty| self.check_type(ty));
+                if let Some(o) = output {
+                    self.check_type(o);
+                }
+            }
+        }
+    }
+
+    fn check_generic_param_def(&mut self, gpd: &'a GenericParamDef) {
+        match &gpd.kind {
+            rustdoc_json_types::GenericParamDefKind::Lifetime { outlives: _ } => {}
+            rustdoc_json_types::GenericParamDefKind::Type { bounds, default, synthetic: _ } => {
+                bounds.iter().for_each(|b| self.check_generic_bound(b));
+                if let Some(ty) = default {
+                    self.check_type(ty);
+                }
+            }
+            rustdoc_json_types::GenericParamDefKind::Const { type_, default: _ } => {
+                self.check_type(type_)
+            }
+        }
+    }
+
+    fn check_generic_arg(&mut self, arg: &'a GenericArg) {
+        match arg {
+            GenericArg::Lifetime(_) => {}
+            GenericArg::Type(ty) => self.check_type(ty),
+            GenericArg::Const(c) => self.check_constant(c),
+            GenericArg::Infer => {}
+        }
+    }
+
+    fn check_type_binding(&mut self, bind: &'a TypeBinding) {
+        self.check_generic_args(&bind.args);
+        match &bind.binding {
+            TypeBindingKind::Equality(term) => self.check_term(term),
+            TypeBindingKind::Constraint(bounds) => {
+                bounds.iter().for_each(|b| self.check_generic_bound(b))
+            }
+        }
+    }
+
+    fn check_term(&mut self, term: &'a Term) {
+        match term {
+            Term::Type(ty) => self.check_type(ty),
+            Term::Constant(con) => self.check_constant(con),
+        }
+    }
+
+    fn check_where_predicate(&mut self, w: &'a WherePredicate) {
+        match w {
+            WherePredicate::BoundPredicate { type_, bounds, generic_params } => {
+                self.check_type(type_);
+                bounds.iter().for_each(|b| self.check_generic_bound(b));
+                generic_params.iter().for_each(|gpd| self.check_generic_param_def(gpd));
+            }
+            WherePredicate::RegionPredicate { lifetime: _, bounds } => {
+                bounds.iter().for_each(|b| self.check_generic_bound(b));
+            }
+            WherePredicate::EqPredicate { lhs, rhs } => {
+                self.check_type(lhs);
+                self.check_term(rhs);
+            }
+        }
+    }
+
+    fn check_dyn_trait(&mut self, dyn_trait: &'a DynTrait) {
+        for pt in &dyn_trait.traits {
+            self.check_path(&pt.trait_, PathKind::Trait);
+            pt.generic_params.iter().for_each(|gpd| self.check_generic_param_def(gpd));
+        }
+    }
+
+    fn check_function_pointer(&mut self, fp: &'a FunctionPointer) {
+        self.check_fn_decl(&fp.decl);
+        fp.generic_params.iter().for_each(|gpd| self.check_generic_param_def(gpd));
+    }
+
+    fn add_id_checked(&mut self, id: &'a Id, valid: fn(Kind) -> bool, expected: &str) {
+        if let Some(kind) = self.kind_of(id) {
+            if valid(kind) {
+                if !self.seen_ids.contains(id) {
+                    self.todo.insert(id);
+                }
+            } else {
+                self.fail_expecting(id, expected);
+            }
+        } else {
+            if !self.missing_ids.contains(id) {
+                self.missing_ids.insert(id);
+                self.fail(id, ErrorKind::NotFound)
+            }
+        }
+    }
+
+    fn add_field_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::is_struct_field, "StructField");
+    }
+
+    fn add_mod_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::is_module, "Module");
+    }
+    fn add_impl_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::is_impl, "Impl");
+    }
+
+    fn add_variant_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::is_variant, "Variant");
+    }
+
+    fn add_trait_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::is_trait, "Trait");
+    }
+
+    fn add_struct_enum_union_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::is_struct_enum_union, "Struct or Enum or Union");
+    }
+
+    /// Add an Id that appeared in a trait
+    fn add_trait_item_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::can_appear_in_trait, "Trait inner item");
+    }
+
+    /// Add an Id that appeared in a mod
+    fn add_mod_item_id(&mut self, id: &'a Id) {
+        self.add_id_checked(id, Kind::can_appear_in_mod, "Module inner item")
+    }
+
+    fn fail_expecting(&mut self, id: &Id, expected: &str) {
+        let kind = self.kind_of(id).unwrap(); // We know it has a kind, as it's wrong.
+        self.fail(id, ErrorKind::Custom(format!("Expected {expected} but found {kind:?}")));
+    }
+
+    fn fail(&mut self, id: &Id, kind: ErrorKind) {
+        self.errs.push(Error { id: id.clone(), kind });
+    }
+
+    fn kind_of(&mut self, id: &Id) -> Option<Kind> {
+        if let Some(item) = self.krate.index.get(id) {
+            Some(Kind::from_item(item))
+        } else if let Some(summary) = self.krate.paths.get(id) {
+            Some(Kind::from_summary(summary))
+        } else {
+            None
+        }
+    }
+}
+
+fn set_remove<T: Hash + Eq + Clone>(set: &mut HashSet<T>) -> Option<T> {
+    if let Some(id) = set.iter().next() {
+        let id = id.clone();
+        set.take(&id)
+    } else {
+        None
+    }
+}
diff --git a/src/tools/linkchecker/main.rs b/src/tools/linkchecker/main.rs
index a7c78d80ccd7..7842611bd4ff 100644
--- a/src/tools/linkchecker/main.rs
+++ b/src/tools/linkchecker/main.rs
@@ -215,6 +215,7 @@ impl Checker {
                 || url.starts_with("ftp:")
                 || url.starts_with("irc:")
                 || url.starts_with("data:")
+                || url.starts_with("mailto:")
             {
                 report.links_ignored_external += 1;
                 return;
diff --git a/src/tools/lint-docs/src/groups.rs b/src/tools/lint-docs/src/groups.rs
index 9696e35b7963..2a923a61b0a7 100644
--- a/src/tools/lint-docs/src/groups.rs
+++ b/src/tools/lint-docs/src/groups.rs
@@ -8,6 +8,7 @@ use std::process::Command;
 /// Descriptions of rustc lint groups.
 static GROUP_DESCRIPTIONS: &[(&str, &str)] = &[
     ("unused", "Lints that detect things being declared but not used, or excess syntax"),
+    ("let-underscore", "Lints that detect wildcard let bindings that are likely to be invalid"),
     ("rustdoc", "Rustdoc-specific lints"),
     ("rust-2018-idioms", "Lints to nudge you toward idiomatic features of Rust 2018"),
     ("nonstandard-style", "Violation of standard naming conventions"),
diff --git a/src/tools/lld-wrapper/src/main.rs b/src/tools/lld-wrapper/src/main.rs
index 90bd24a75e06..b5e977b2637d 100644
--- a/src/tools/lld-wrapper/src/main.rs
+++ b/src/tools/lld-wrapper/src/main.rs
@@ -8,12 +8,13 @@
 //! make gcc/clang pass `-flavor <flavor>` as the first two arguments in the linker invocation
 //! and since Windows does not support symbolic links for files this wrapper is used in place of a
 //! symbolic link. It execs `../rust-lld -flavor <flavor>` by propagating the flavor argument
-//! passed to the wrapper as the first two arguments. On Windows it spawns a `..\rust-lld.exe`
-//! child process.
+//! obtained from the wrapper's name as the first two arguments.
+//! On Windows it spawns a `..\rust-lld.exe` child process.
 
+use std::env::{self, consts::EXE_SUFFIX};
 use std::fmt::Display;
 use std::path::{Path, PathBuf};
-use std::{env, process};
+use std::process;
 
 trait UnwrapOrExitWith<T> {
     fn unwrap_or_exit_with(self, context: &str) -> T;
@@ -42,7 +43,7 @@ impl<T, E: Display> UnwrapOrExitWith<T> for Result<T, E> {
 /// Exits if the parent directory cannot be determined.
 fn get_rust_lld_path(current_exe_path: &Path) -> PathBuf {
     let mut rust_lld_exe_name = "rust-lld".to_owned();
-    rust_lld_exe_name.push_str(env::consts::EXE_SUFFIX);
+    rust_lld_exe_name.push_str(EXE_SUFFIX);
     let mut rust_lld_path = current_exe_path
         .parent()
         .unwrap_or_exit_with("directory containing current executable could not be determined")
@@ -53,29 +54,33 @@ fn get_rust_lld_path(current_exe_path: &Path) -> PathBuf {
     rust_lld_path
 }
 
+/// Extract LLD flavor name from the lld-wrapper executable name.
+fn get_lld_flavor(current_exe_path: &Path) -> Result<&'static str, String> {
+    let file = current_exe_path.file_name();
+    let stem = file.and_then(|s| s.to_str()).map(|s| s.trim_end_matches(EXE_SUFFIX));
+    Ok(match stem {
+        Some("ld.lld") => "gnu",
+        Some("ld64.lld") => "darwin",
+        Some("lld-link") => "link",
+        Some("wasm-ld") => "wasm",
+        _ => return Err(format!("{:?}", file)),
+    })
+}
+
 /// Returns the command for invoking rust-lld with the correct flavor.
-/// LLD only accepts the flavor argument at the first two arguments, so move it there.
+/// LLD only accepts the flavor argument at the first two arguments, so pass it there.
 ///
 /// Exits on error.
 fn get_rust_lld_command(current_exe_path: &Path) -> process::Command {
     let rust_lld_path = get_rust_lld_path(current_exe_path);
     let mut command = process::Command::new(rust_lld_path);
 
-    let mut flavor = None;
-    let args = env::args_os()
-        .skip(1)
-        .filter(|arg| match arg.to_str().and_then(|s| s.strip_prefix("-rustc-lld-flavor=")) {
-            Some(suffix) => {
-                flavor = Some(suffix.to_string());
-                false
-            }
-            None => true,
-        })
-        .collect::<Vec<_>>();
+    let flavor =
+        get_lld_flavor(current_exe_path).unwrap_or_exit_with("executable has unexpected name");
 
     command.arg("-flavor");
-    command.arg(flavor.unwrap_or_exit_with("-rustc-lld-flavor=<flavor> is not passed"));
-    command.args(args);
+    command.arg(flavor);
+    command.args(env::args_os().skip(1));
     command
 }
 
diff --git a/src/tools/miri b/src/tools/miri
deleted file mode 160000
index ab88e64b152d..000000000000
--- a/src/tools/miri
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit ab88e64b152d3704c35db96dbbc6efaaed67773f
diff --git a/src/tools/miri/.editorconfig b/src/tools/miri/.editorconfig
new file mode 100644
index 000000000000..3c1f41bdcca6
--- /dev/null
+++ b/src/tools/miri/.editorconfig
@@ -0,0 +1,25 @@
+# EditorConfig helps developers define and maintain consistent
+# coding styles between different editors and IDEs
+# editorconfig.org
+
+root = true
+
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = space
+indent_size = 4
+
+[*.rs]
+indent_style = space
+indent_size = 4
+
+[*.toml]
+indent_style = space
+indent_size = 4
+
+[*.md]
+trim_trailing_whitespace = false
diff --git a/src/tools/miri/.gitattributes b/src/tools/miri/.gitattributes
new file mode 100644
index 000000000000..2742e4d1d5b9
--- /dev/null
+++ b/src/tools/miri/.gitattributes
@@ -0,0 +1,6 @@
+* text=auto eol=lf
+
+# Older git versions try to fix line endings on images, this prevents it.
+*.png binary
+*.jpg binary
+*.ico binary
diff --git a/src/tools/miri/.github/workflows/ci.yml b/src/tools/miri/.github/workflows/ci.yml
new file mode 100644
index 000000000000..80d150e1df15
--- /dev/null
+++ b/src/tools/miri/.github/workflows/ci.yml
@@ -0,0 +1,156 @@
+name: CI
+
+on:
+  push:
+    # Run in PRs and for bors, but not on master.
+    branches:
+      - 'auto'
+      - 'try'
+  pull_request:
+    branches:
+      - 'master'
+  schedule:
+    - cron: '5 15 * * *' # At 15:05 UTC every day.
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    env:
+      RUST_BACKTRACE: 1
+      HOST_TARGET: ${{ matrix.host_target }}
+    strategy:
+      matrix:
+        build: [linux64, macos, win32]
+        include:
+          - build: linux64
+            os: ubuntu-latest
+            host_target: x86_64-unknown-linux-gnu
+          - build: macos
+            os: macos-latest
+            host_target: x86_64-apple-darwin
+          - build: win32
+            os: windows-latest
+            host_target: i686-pc-windows-msvc
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set the tag GC interval to 1 on linux
+        if: runner.os == 'Linux'
+        run: echo "MIRIFLAGS=-Zmiri-tag-gc=1" >> $GITHUB_ENV
+
+      # We install gnu-tar because BSD tar is buggy on macOS builders of GHA.
+      # See <https://github.com/actions/cache/issues/403>.
+      - name: Install GNU tar
+        if: runner.os == 'macOS'
+        run: |
+          brew install gnu-tar
+          echo "/usr/local/opt/gnu-tar/libexec/gnubin" >> $GITHUB_PATH
+
+      # Cache the global cargo directory, but NOT the local `target` directory which
+      # we cannot reuse anyway when the nightly changes (and it grows quite large
+      # over time).
+      - name: Add cache for cargo
+        id: cache
+        uses: actions/cache@v3
+        with:
+          path: |
+            # Taken from <https://doc.rust-lang.org/nightly/cargo/guide/cargo-home.html#caching-the-cargo-home-in-ci>.
+            ~/.cargo/bin
+            ~/.cargo/registry/index
+            ~/.cargo/registry/cache
+            ~/.cargo/git/db
+            # contains package information of crates installed via `cargo install`.
+            ~/.cargo/.crates.toml
+            ~/.cargo/.crates2.json
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock', 'cargo-miri/src/version.rs') }}
+          restore-keys: ${{ runner.os }}-cargo
+
+      - name: Install rustup-toolchain-install-master and xargo
+        if: ${{ steps.cache.outputs.cache-hit == 'false' }}
+        shell: bash
+        run: |
+          cargo install rustup-toolchain-install-master
+          cargo install xargo
+
+      - name: Install "master" toolchain
+        shell: bash
+        run: |
+          if [[ ${{ github.event_name }} == 'schedule' ]]; then
+            ./rustup-toolchain HEAD --host ${{ matrix.host_target }}
+          else
+            ./rustup-toolchain "" --host ${{ matrix.host_target }}
+          fi
+
+      - name: Show Rust version
+        run: |
+          rustup show
+          rustc -Vv
+          cargo -V
+
+      - name: Test
+        run: bash ./ci.sh
+
+  style:
+    name: style checks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install required toolchain
+        # We need a toolchain that can actually build Miri, just a nightly won't do.
+        run: |
+          cargo install rustup-toolchain-install-master # TODO: cache this?
+          ./rustup-toolchain "" -c clippy
+      - name: rustfmt
+        run: ./miri fmt --check
+      - name: clippy
+        run: ./miri clippy -- -D warnings
+      - name: rustdoc
+        run: RUSTDOCFLAGS="-Dwarnings" cargo doc --document-private-items
+
+  # These jobs doesn't actually test anything, but they're only used to tell
+  # bors the build completed, as there is no practical way to detect when a
+  # workflow is successful listening to webhooks only.
+  #
+  # ALL THE PREVIOUS JOBS NEED TO BE ADDED TO THE `needs` SECTION OF THIS JOB!
+  # (`fmt` is deliberately not listed, we want bors to ignore it.)
+  end-success:
+    name: bors build finished
+    runs-on: ubuntu-latest
+    needs: [build, style]
+    if: github.event.pusher.name == 'bors' && success()
+    steps:
+      - name: mark the job as a success
+        run: exit 0
+  end-failure:
+    name: bors build finished
+    runs-on: ubuntu-latest
+    needs: [build, style]
+    if: github.event.pusher.name == 'bors' && (failure() || cancelled())
+    steps:
+      - name: mark the job as a failure
+        run: exit 1
+
+  # Send a Zulip notification when a cron job fails
+  cron-fail-notify:
+    name: cronjob failure notification
+    runs-on: ubuntu-latest
+    needs: [build, style]
+    if: github.event_name == 'schedule' && (failure() || cancelled())
+    steps:
+      - name: Install zulip-send
+        run: pip3 install zulip
+      - name: Send Zulip notification
+        shell: bash
+        env:
+          ZULIP_BOT_EMAIL: ${{ secrets.ZULIP_BOT_EMAIL }}
+          ZULIP_API_TOKEN: ${{ secrets.ZULIP_API_TOKEN }}
+        run: |
+          ~/.local/bin/zulip-send --stream miri --subject "Cron Job Failure (miri, $(date -u +%Y-%m))" \
+            --message 'Dear @*T-miri*,
+
+          It would appear that the Miri cron job build failed. Would you mind investigating this issue?
+
+          Thanks in advance!
+          Sincerely,
+          The Miri Cronjobs Bot' \
+            --user $ZULIP_BOT_EMAIL --api-key $ZULIP_API_TOKEN --site https://rust-lang.zulipchat.com
diff --git a/src/tools/miri/.gitignore b/src/tools/miri/.gitignore
new file mode 100644
index 000000000000..924a93e807fe
--- /dev/null
+++ b/src/tools/miri/.gitignore
@@ -0,0 +1,13 @@
+target
+/doc
+tex/*/out
+*.dot
+*.out
+*.rs.bk
+.vscode
+*.mm_profdata
+perf.data
+perf.data.old
+flamegraph.svg
+tests/extern-so/libtestlib.so
+.auto-*
diff --git a/src/tools/miri/.gitpod.yml b/src/tools/miri/.gitpod.yml
new file mode 100644
index 000000000000..36bd991740a8
--- /dev/null
+++ b/src/tools/miri/.gitpod.yml
@@ -0,0 +1,9 @@
+image: ubuntu:latest
+
+tasks:
+  - before: echo "..."
+    init: |
+      cargo install rustup-toolchain-install-master
+      ./rustup-toolchain
+      ./miri build
+    command: echo "Run tests with ./miri test"
\ No newline at end of file
diff --git a/src/tools/miri/CONTRIBUTING.md b/src/tools/miri/CONTRIBUTING.md
new file mode 100644
index 000000000000..8d965ae8fcb8
--- /dev/null
+++ b/src/tools/miri/CONTRIBUTING.md
@@ -0,0 +1,277 @@
+# Contribution Guide
+
+If you want to hack on Miri yourself, great!  Here are some resources you might
+find useful.
+
+## Getting started
+
+Check out the issues on this GitHub repository for some ideas. In particular,
+look for the green `E-*` labels which mark issues that should be rather
+well-suited for onboarding. For more ideas or help with hacking on Miri, you can
+contact us (`oli-obk` and `RalfJ`) on the [Rust Zulip].
+
+[Rust Zulip]: https://rust-lang.zulipchat.com
+
+## Preparing the build environment
+
+Miri heavily relies on internal and unstable rustc interfaces to execute MIR,
+which means it is important that you install a version of rustc that Miri
+actually works with.
+
+The `rust-version` file contains the commit hash of rustc that Miri is currently
+tested against. Other versions will likely not work. After installing
+[`rustup-toolchain-install-master`], you can run the following command to
+install that exact version of rustc as a toolchain:
+```
+./rustup-toolchain
+```
+This will set up a rustup toolchain called `miri` and set it as an override for
+the current directory.
+
+You can also create a `.auto-everything` file (contents don't matter, can be empty), which
+will cause any `./miri` command to automatically call `rustup-toolchain`, `clippy` and `rustfmt`
+for you. If you don't want all of these to happen, you can add individual `.auto-toolchain`,
+`.auto-clippy` and `.auto-fmt` files respectively.
+
+[`rustup-toolchain-install-master`]: https://github.com/kennytm/rustup-toolchain-install-master
+
+## Building and testing Miri
+
+Invoking Miri requires getting a bunch of flags right and setting up a custom
+sysroot with xargo. The `miri` script takes care of that for you. With the
+build environment prepared, compiling Miri is just one command away:
+
+```
+./miri build
+```
+
+Run `./miri` without arguments to see the other commands our build tool
+supports.
+
+### Testing the Miri driver
+
+The Miri driver compiled from `src/bin/miri.rs` is the "heart" of Miri: it is
+basically a version of `rustc` that, instead of compiling your code, runs it.
+It accepts all the same flags as `rustc` (though the ones only affecting code
+generation and linking obviously will have no effect) [and more][miri-flags].
+
+[miri-flags]: README.md#miri--z-flags-and-environment-variables
+
+For example, you can (cross-)run the driver on a particular file by doing
+
+```sh
+./miri run tests/pass/format.rs
+./miri run tests/pass/hello.rs --target i686-unknown-linux-gnu
+```
+
+and you can (cross-)run the entire test suite using:
+
+```
+./miri test
+MIRI_TEST_TARGET=i686-unknown-linux-gnu ./miri test
+```
+
+If your target doesn't support libstd, you can run miri with
+
+```
+MIRI_NO_STD=1 MIRI_TEST_TARGET=thumbv7em-none-eabihf ./miri test tests/fail/alloc/no_global_allocator.rs
+MIRI_NO_STD=1 ./miri run tests/pass/no_std.rs --target thumbv7em-none-eabihf
+```
+
+to avoid attempting (and failing) to build libstd. Note that almost no tests will pass
+this way, but you can run individual tests.
+
+`./miri test FILTER` only runs those tests that contain `FILTER` in their
+filename (including the base directory, e.g. `./miri test fail` will run all
+compile-fail tests).
+
+You can get a trace of which MIR statements are being executed by setting the
+`MIRI_LOG` environment variable.  For example:
+
+```sh
+MIRI_LOG=info ./miri run tests/pass/vec.rs
+```
+
+Setting `MIRI_LOG` like this will configure logging for Miri itself as well as
+the `rustc_middle::mir::interpret` and `rustc_mir::interpret` modules in rustc. You
+can also do more targeted configuration, e.g. the following helps debug the
+stacked borrows implementation:
+
+```sh
+MIRI_LOG=rustc_mir::interpret=info,miri::stacked_borrows ./miri run tests/pass/vec.rs
+```
+
+In addition, you can set `MIRI_BACKTRACE=1` to get a backtrace of where an
+evaluation error was originally raised.
+
+#### UI testing
+
+We use ui-testing in Miri, meaning we generate `.stderr` and `.stdout` files for the output
+produced by Miri. You can use `./miri bless` to automatically (re)generate these files when
+you add new tests or change how Miri presents certain output.
+
+Note that when you also use `MIRIFLAGS` to change optimizations and similar, the ui output
+will change in unexpected ways. In order to still be able
+to run the other checks while ignoring the ui output, use `MIRI_SKIP_UI_CHECKS=1 ./miri test`.
+
+For more info on how to configure ui tests see [the documentation on the ui test crate][ui_test]
+
+[ui_test]: ui_test/README.md
+
+### Testing `cargo miri`
+
+Working with the driver directly gives you full control, but you also lose all
+the convenience provided by cargo. Once your test case depends on a crate, it
+is probably easier to test it with the cargo wrapper. You can install your
+development version of Miri using
+
+```
+./miri install
+```
+
+and then you can use it as if it was installed by `rustup`.  Make sure you use
+the same toolchain when calling `cargo miri` that you used when installing Miri!
+Usually this means you have to write `cargo +miri miri ...` to select the `miri`
+toolchain that was installed by `./rustup-toolchain`.
+
+There's a test for the cargo wrapper in the `test-cargo-miri` directory; run
+`./run-test.py` in there to execute it. Like `./miri test`, this respects the
+`MIRI_TEST_TARGET` environment variable to execute the test for another target.
+
+### Using a modified standard library
+
+Miri re-builds the standard library into a custom sysroot, so it is fairly easy
+to test Miri against a modified standard library -- you do not even have to
+build Miri yourself, the Miri shipped by `rustup` will work. All you have to do
+is set the `MIRI_LIB_SRC` environment variable to the `library` folder of a
+`rust-lang/rust` repository checkout. Note that changing files in that directory
+does not automatically trigger a re-build of the standard library; you have to
+clear the Miri build cache manually (on Linux, `rm -rf ~/.cache/miri`;
+and on Windows, `rmdir /S "%LOCALAPPDATA%\rust-lang\miri\cache"`).
+
+### Benchmarking
+
+Miri comes with a few benchmarks; you can run `./miri bench` to run them with the locally built
+Miri. Note: this will run `./miri install` as a side-effect. Also requires `hyperfine` to be
+installed (`cargo install hyperfine`).
+
+## Configuring `rust-analyzer`
+
+To configure `rust-analyzer` and VS Code for working on Miri, save the following
+to `.vscode/settings.json` in your local Miri clone:
+
+```json
+{
+    "rust-analyzer.rustc.source": "discover",
+    "rust-analyzer.linkedProjects": [
+        "./Cargo.toml",
+        "./cargo-miri/Cargo.toml"
+    ],
+    "rust-analyzer.checkOnSave.overrideCommand": [
+        "env",
+        "MIRI_AUTO_OPS=no",
+        "./miri",
+        "cargo",
+        "clippy", // make this `check` when working with a locally built rustc
+        "--message-format=json"
+    ],
+    // Contrary to what the name suggests, this also affects proc macros.
+    "rust-analyzer.cargo.buildScripts.overrideCommand": [
+        "env",
+        "MIRI_AUTO_OPS=no",
+        "./miri",
+        "cargo",
+        "check",
+        "--message-format=json",
+    ],
+}
+```
+
+> #### Note
+>
+> If you are [building Miri with a locally built rustc][], set
+> `rust-analyzer.rustcSource` to the relative path from your Miri clone to the
+> root `Cargo.toml` of the locally built rustc. For example, the path might look
+> like `../rust/Cargo.toml`.
+
+See the rustc-dev-guide's docs on ["Configuring `rust-analyzer` for `rustc`"][rdg-r-a]
+for more information about configuring VS Code and `rust-analyzer`.
+
+[rdg-r-a]: https://rustc-dev-guide.rust-lang.org/building/suggested.html#configuring-rust-analyzer-for-rustc
+
+## Advanced topic: other build environments
+
+We described above the simplest way to get a working build environment for Miri,
+which is to use the version of rustc indicated by `rustc-version`. But
+sometimes, that is not enough.
+
+### Updating `rustc-version`
+
+The `rustc-version` file is regularly updated to keep Miri close to the latest
+version of rustc. Usually, new contributors do not have to worry about this. But
+sometimes a newer rustc is needed for a patch, and sometimes Miri needs fixing
+for changes in rustc. In both cases, `rustc-version` needs updating.
+
+To update the `rustc-version` file and install the latest rustc, you can run:
+```
+./rustup-toolchain HEAD
+```
+
+Now edit Miri until `./miri test` passes, and submit a PR. Generally, it is
+preferred to separate updating `rustc-version` and doing what it takes to get
+Miri working again, from implementing new features that rely on the updated
+rustc. This avoids blocking all Miri development on landing a big PR.
+
+### Building Miri with a locally built rustc
+
+[building Miri with a locally built rustc]: #building-miri-with-a-locally-built-rustc
+
+A big part of the Miri driver lives in rustc, so working on Miri will sometimes
+require using a locally built rustc. The bug you want to fix may actually be on
+the rustc side, or you just need to get more detailed trace of the execution
+than what is possible with release builds -- in both cases, you should develop
+Miri against a rustc you compiled yourself, with debug assertions (and hence
+tracing) enabled.
+
+The setup for a local rustc works as follows:
+```sh
+# Clone the rust-lang/rust repo.
+git clone https://github.com/rust-lang/rust rustc
+cd rustc
+# Create a config.toml with defaults for working on Miri.
+./x.py setup compiler
+ # Now edit `config.toml` and under `[rust]` set `debug-assertions = true`.
+
+# Build a stage 2 rustc, and build the rustc libraries with that rustc.
+# This step can take 30 minutes or more.
+./x.py build --stage 2 compiler/rustc
+# If you change something, you can get a faster rebuild by doing
+./x.py build --keep-stage 0 --stage 2 compiler/rustc
+# You may have to change the architecture in the next command
+rustup toolchain link stage2 build/x86_64-unknown-linux-gnu/stage2
+# Now cd to your Miri directory, then configure rustup
+rustup override set stage2
+```
+
+Note: When you are working with a locally built rustc or any other toolchain that
+is not the same as the one in `rust-version`, you should not have `.auto-everything` or
+`.auto-toolchain` as that will keep resetting your toolchain.
+
+```
+rm -f .auto-everything .auto-toolchain
+```
+
+Important: You need to delete the Miri cache when you change the stdlib; otherwise the
+old, chached version will be used. On Linux, the cache is located at `~/.cache/miri`,
+and on Windows, it is located at `%LOCALAPPDATA%\rust-lang\miri\cache`; the exact
+location is printed after the library build: "A libstd for Miri is now available in ...".
+
+Note: `./x.py --stage 2 compiler/rustc` currently errors with `thread 'main'
+panicked at 'fs::read(stamp) failed with No such file or directory (os error 2)`,
+you can simply ignore that error; Miri will build anyway.
+
+For more information about building and configuring a local compiler,
+see <https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html>.
+
+With this, you should now have a working development setup! See
+[above](#building-and-testing-miri) for how to proceed working on Miri.
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new file mode 100644
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diff --git a/src/tools/miri/Cargo.toml b/src/tools/miri/Cargo.toml
new file mode 100644
index 000000000000..0c547d585d19
--- /dev/null
+++ b/src/tools/miri/Cargo.toml
@@ -0,0 +1,61 @@
+[package]
+authors = ["Miri Team"]
+description = "An experimental interpreter for Rust MIR (core driver)."
+license = "MIT OR Apache-2.0"
+name = "miri"
+repository = "https://github.com/rust-lang/miri"
+version = "0.1.0"
+default-run = "miri"
+edition = "2021"
+
+[lib]
+test = true # we have unit tests
+doctest = false # but no doc tests
+
+[[bin]]
+name = "miri"
+test = false # we have no unit tests
+doctest = false # and no doc tests
+
+[dependencies]
+getrandom = { version = "0.2", features = ["std"] }
+env_logger = "0.9"
+log = "0.4"
+shell-escape = "0.1.4"
+rand = "0.8"
+smallvec = "1.7"
+
+# A noop dependency that changes in the Rust repository, it's a bit of a hack.
+# See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`
+# for more information.
+rustc-workspace-hack = "1.0.0"
+measureme = "10.0.0"
+
+[target."cfg(unix)".dependencies]
+libc = "0.2"
+libffi = "3.0.0"
+libloading = "0.7"
+
+[dev-dependencies]
+colored = "2"
+ui_test = "0.3.1"
+# Features chosen to match those required by env_logger, to avoid rebuilds
+regex = { version = "1.5.5", default-features = false, features = ["perf", "std"] }
+lazy_static = "1.4.0"
+
+[package.metadata.rust-analyzer]
+# This crate uses #[feature(rustc_private)].
+# See https://github.com/rust-analyzer/rust-analyzer/pull/7891
+rustc_private = true
+
+[[test]]
+name = "compiletest"
+harness = false
+
+[features]
+default = ["stack-cache"]
+stack-cache = []
+
+# Be aware that this file is inside a workspace when used via the
+# submodule in the rustc repo. That means there are many cargo features
+# we cannot use, such as profiles.
diff --git a/src/tools/miri/LICENSE-APACHE b/src/tools/miri/LICENSE-APACHE
new file mode 100644
index 000000000000..1b5ec8b78e23
--- /dev/null
+++ b/src/tools/miri/LICENSE-APACHE
@@ -0,0 +1,176 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
+   "License" shall mean the terms and conditions for use, reproduction,
+   and distribution as defined by Sections 1 through 9 of this document.
+
+   "Licensor" shall mean the copyright owner or entity authorized by
+   the copyright owner that is granting the License.
+
+   "Legal Entity" shall mean the union of the acting entity and all
+   other entities that control, are controlled by, or are under common
+   control with that entity. For the purposes of this definition,
+   "control" means (i) the power, direct or indirect, to cause the
+   direction or management of such entity, whether by contract or
+   otherwise, or (ii) ownership of fifty percent (50%) or more of the
+   outstanding shares, or (iii) beneficial ownership of such entity.
+
+   "You" (or "Your") shall mean an individual or Legal Entity
+   exercising permissions granted by this License.
+
+   "Source" form shall mean the preferred form for making modifications,
+   including but not limited to software source code, documentation
+   source, and configuration files.
+
+   "Object" form shall mean any form resulting from mechanical
+   transformation or translation of a Source form, including but
+   not limited to compiled object code, generated documentation,
+   and conversions to other media types.
+
+   "Work" shall mean the work of authorship, whether in Source or
+   Object form, made available under the License, as indicated by a
+   copyright notice that is included in or attached to the work
+   (an example is provided in the Appendix below).
+
+   "Derivative Works" shall mean any work, whether in Source or Object
+   form, that is based on (or derived from) the Work and for which the
+   editorial revisions, annotations, elaborations, or other modifications
+   represent, as a whole, an original work of authorship. For the purposes
+   of this License, Derivative Works shall not include works that remain
+   separable from, or merely link (or bind by name) to the interfaces of,
+   the Work and Derivative Works thereof.
+
+   "Contribution" shall mean any work of authorship, including
+   the original version of the Work and any modifications or additions
+   to that Work or Derivative Works thereof, that is intentionally
+   submitted to Licensor for inclusion in the Work by the copyright owner
+   or by an individual or Legal Entity authorized to submit on behalf of
+   the copyright owner. For the purposes of this definition, "submitted"
+   means any form of electronic, verbal, or written communication sent
+   to the Licensor or its representatives, including but not limited to
+   communication on electronic mailing lists, source code control systems,
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+   Licensor for the purpose of discussing and improving the Work, but
+   excluding communication that is conspicuously marked or otherwise
+   designated in writing by the copyright owner as "Not a Contribution."
+
+   "Contributor" shall mean Licensor and any individual or Legal Entity
+   on behalf of whom a Contribution has been received by Licensor and
+   subsequently incorporated within the Work.
+
+2. Grant of Copyright License. Subject to the terms and conditions of
+   this License, each Contributor hereby grants to You a perpetual,
+   worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+   copyright license to reproduce, prepare Derivative Works of,
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+3. Grant of Patent License. Subject to the terms and conditions of
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+   or a Contribution incorporated within the Work constitutes direct
+   or contributory patent infringement, then any patent licenses
+   granted to You under this License for that Work shall terminate
+   as of the date such litigation is filed.
+
+4. Redistribution. You may reproduce and distribute copies of the
+   Work or Derivative Works thereof in any medium, with or without
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+   meet the following conditions:
+
+   (a) You must give any other recipients of the Work or
+       Derivative Works a copy of this License; and
+
+   (b) You must cause any modified files to carry prominent notices
+       stating that You changed the files; and
+
+   (c) You must retain, in the Source form of any Derivative Works
+       that You distribute, all copyright, patent, trademark, and
+       attribution notices from the Source form of the Work,
+       excluding those notices that do not pertain to any part of
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+
+   (d) If the Work includes a "NOTICE" text file as part of its
+       distribution, then any Derivative Works that You distribute must
+       include a readable copy of the attribution notices contained
+       within such NOTICE file, excluding those notices that do not
+       pertain to any part of the Derivative Works, in at least one
+       of the following places: within a NOTICE text file distributed
+       as part of the Derivative Works; within the Source form or
+       documentation, if provided along with the Derivative Works; or,
+       within a display generated by the Derivative Works, if and
+       wherever such third-party notices normally appear. The contents
+       of the NOTICE file are for informational purposes only and
+       do not modify the License. You may add Your own attribution
+       notices within Derivative Works that You distribute, alongside
+       or as an addendum to the NOTICE text from the Work, provided
+       that such additional attribution notices cannot be construed
+       as modifying the License.
+
+   You may add Your own copyright statement to Your modifications and
+   may provide additional or different license terms and conditions
+   for use, reproduction, or distribution of Your modifications, or
+   for any such Derivative Works as a whole, provided Your use,
+   reproduction, and distribution of the Work otherwise complies with
+   the conditions stated in this License.
+
+5. Submission of Contributions. Unless You explicitly state otherwise,
+   any Contribution intentionally submitted for inclusion in the Work
+   by You to the Licensor shall be under the terms and conditions of
+   this License, without any additional terms or conditions.
+   Notwithstanding the above, nothing herein shall supersede or modify
+   the terms of any separate license agreement you may have executed
+   with Licensor regarding such Contributions.
+
+6. Trademarks. This License does not grant permission to use the trade
+   names, trademarks, service marks, or product names of the Licensor,
+   except as required for reasonable and customary use in describing the
+   origin of the Work and reproducing the content of the NOTICE file.
+
+7. Disclaimer of Warranty. Unless required by applicable law or
+   agreed to in writing, Licensor provides the Work (and each
+   Contributor provides its Contributions) on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+   implied, including, without limitation, any warranties or conditions
+   of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+   PARTICULAR PURPOSE. You are solely responsible for determining the
+   appropriateness of using or redistributing the Work and assume any
+   risks associated with Your exercise of permissions under this License.
+
+8. Limitation of Liability. In no event and under no legal theory,
+   whether in tort (including negligence), contract, or otherwise,
+   unless required by applicable law (such as deliberate and grossly
+   negligent acts) or agreed to in writing, shall any Contributor be
+   liable to You for damages, including any direct, indirect, special,
+   incidental, or consequential damages of any character arising as a
+   result of this License or out of the use or inability to use the
+   Work (including but not limited to damages for loss of goodwill,
+   work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses), even if such Contributor
+   has been advised of the possibility of such damages.
+
+9. Accepting Warranty or Additional Liability. While redistributing
+   the Work or Derivative Works thereof, You may choose to offer,
+   and charge a fee for, acceptance of support, warranty, indemnity,
+   or other liability obligations and/or rights consistent with this
+   License. However, in accepting such obligations, You may act only
+   on Your own behalf and on Your sole responsibility, not on behalf
+   of any other Contributor, and only if You agree to indemnify,
+   defend, and hold each Contributor harmless for any liability
+   incurred by, or claims asserted against, such Contributor by reason
+   of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
diff --git a/src/tools/miri/LICENSE-MIT b/src/tools/miri/LICENSE-MIT
new file mode 100644
index 000000000000..31aa79387f27
--- /dev/null
+++ b/src/tools/miri/LICENSE-MIT
@@ -0,0 +1,23 @@
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/src/tools/miri/README.md b/src/tools/miri/README.md
new file mode 100644
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@@ -0,0 +1,639 @@
+# Miri
+
+[![Actions build status][actions-badge]][actions-url]
+
+[actions-badge]: https://github.com/rust-lang/miri/workflows/CI/badge.svg?branch=master
+[actions-url]: https://github.com/rust-lang/miri/actions
+
+An experimental interpreter for [Rust][rust]'s
+[mid-level intermediate representation][mir] (MIR). It can run binaries and
+test suites of cargo projects and detect certain classes of
+[undefined behavior](https://doc.rust-lang.org/reference/behavior-considered-undefined.html),
+for example:
+
+* Out-of-bounds memory accesses and use-after-free
+* Invalid use of uninitialized data
+* Violation of intrinsic preconditions (an [`unreachable_unchecked`] being
+  reached, calling [`copy_nonoverlapping`] with overlapping ranges, ...)
+* Not sufficiently aligned memory accesses and references
+* Violation of *some* basic type invariants (a `bool` that is not 0 or 1, for example,
+  or an invalid enum discriminant)
+* **Experimental**: Violations of the [Stacked Borrows] rules governing aliasing
+  for reference types
+* **Experimental**: Data races
+
+On top of that, Miri will also tell you about memory leaks: when there is memory
+still allocated at the end of the execution, and that memory is not reachable
+from a global `static`, Miri will raise an error.
+
+Miri supports almost all Rust language features; in particular, unwinding and
+concurrency are properly supported (including some experimental emulation of
+weak memory effects, i.e., reads can return outdated values).
+
+You can use Miri to emulate programs on other targets, e.g. to ensure that
+byte-level data manipulation works correctly both on little-endian and
+big-endian systems. See
+[cross-interpretation](#cross-interpretation-running-for-different-targets)
+below.
+
+Miri has already discovered some [real-world bugs](#bugs-found-by-miri). If you
+found a bug with Miri, we'd appreciate if you tell us and we'll add it to the
+list!
+
+By default, Miri ensures a fully deterministic execution and isolates the
+program from the host system. Some APIs that would usually access the host, such
+as gathering entropy for random number generators, environment variables, and
+clocks, are replaced by deterministic "fake" implementations. Set
+`MIRIFLAGS="-Zmiri-disable-isolation"` to access the real system APIs instead.
+(In particular, the "fake" system RNG APIs make Miri **not suited for
+cryptographic use**! Do not generate keys using Miri.)
+
+All that said, be aware that Miri will **not catch all cases of undefined
+behavior** in your program, and cannot run all programs:
+
+* There are still plenty of open questions around the basic invariants for some
+  types and when these invariants even have to hold. Miri tries to avoid false
+  positives here, so if your program runs fine in Miri right now that is by no
+  means a guarantee that it is UB-free when these questions get answered.
+
+    In particular, Miri does currently not check that references point to valid data.
+* If the program relies on unspecified details of how data is laid out, it will
+  still run fine in Miri -- but might break (including causing UB) on different
+  compiler versions or different platforms.
+* Program execution is non-deterministic when it depends, for example, on where
+  exactly in memory allocations end up, or on the exact interleaving of
+  concurrent threads. Miri tests one of many possible executions of your
+  program. You can alleviate this to some extent by running Miri with different
+  values for `-Zmiri-seed`, but that will still by far not explore all possible
+  executions.
+* Miri runs the program as a platform-independent interpreter, so the program
+  has no access to most platform-specific APIs or FFI. A few APIs have been
+  implemented (such as printing to stdout, accessing environment variables, and
+  basic file system access) but most have not: for example, Miri currently does
+  not support networking. System API support varies between targets; if you run
+  on Windows it is a good idea to use `--target x86_64-unknown-linux-gnu` to get
+  better support.
+* Weak memory emulation may [produce weak behaviours](https://github.com/rust-lang/miri/issues/2301)
+  unobservable by compiled programs running on real hardware when `SeqCst` fences are used, and it
+  cannot produce all behaviors possibly observable on real hardware.
+
+[rust]: https://www.rust-lang.org/
+[mir]: https://github.com/rust-lang/rfcs/blob/master/text/1211-mir.md
+[`unreachable_unchecked`]: https://doc.rust-lang.org/stable/std/hint/fn.unreachable_unchecked.html
+[`copy_nonoverlapping`]: https://doc.rust-lang.org/stable/std/ptr/fn.copy_nonoverlapping.html
+[Stacked Borrows]: https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md
+
+
+## Using Miri
+
+Install Miri on Rust nightly via `rustup`:
+
+```sh
+rustup +nightly component add miri
+```
+
+If `rustup` says the `miri` component is unavailable, that's because not all
+nightly releases come with all tools. Check out
+[this website](https://rust-lang.github.io/rustup-components-history) to
+determine a nightly version that comes with Miri and install that using `rustup
+toolchain install nightly-YYYY-MM-DD`. Either way, all of the following commands
+assume the right toolchain is pinned via `rustup override set nightly` or
+`rustup override set nightly-YYYY-MM-DD`. (Alternatively, use `cargo
++nightly`/`cargo +nightly-YYYY-MM-DD` for each of the following commands.)
+
+Now you can run your project in Miri:
+
+1. Run `cargo clean` to eliminate any cached dependencies. Miri needs your
+   dependencies to be compiled the right way, that would not happen if they have
+   previously already been compiled.
+2. To run all tests in your project through Miri, use `cargo miri test`.
+3. If you have a binary project, you can run it through Miri using `cargo miri run`.
+
+The first time you run Miri, it will perform some extra setup and install some
+dependencies. It will ask you for confirmation before installing anything.
+
+`cargo miri run/test` supports the exact same flags as `cargo run/test`. For
+example, `cargo miri test filter` only runs the tests containing `filter` in
+their name.
+
+You can pass arguments to Miri via `MIRIFLAGS`. For example,
+`MIRIFLAGS="-Zmiri-disable-stacked-borrows" cargo miri run` runs the program
+without checking the aliasing of references.
+
+When compiling code via `cargo miri`, the `cfg(miri)` config flag is set for code
+that will be interpret under Miri. You can use this to ignore test cases that fail
+under Miri because they do things Miri does not support:
+
+```rust
+#[test]
+#[cfg_attr(miri, ignore)]
+fn does_not_work_on_miri() {
+    tokio::run(futures::future::ok::<_, ()>(()));
+}
+```
+
+There is no way to list all the infinite things Miri cannot do, but the
+interpreter will explicitly tell you when it finds something unsupported:
+
+```
+error: unsupported operation: can't call foreign function: bind
+    ...
+    = help: this is likely not a bug in the program; it indicates that the program \
+            performed an operation that the interpreter does not support
+```
+
+### Cross-interpretation: running for different targets
+
+Miri can not only run a binary or test suite for your host target, it can also
+perform cross-interpretation for arbitrary foreign targets: `cargo miri run
+--target x86_64-unknown-linux-gnu` will run your program as if it was a Linux
+program, no matter your host OS. This is particularly useful if you are using
+Windows, as the Linux target is much better supported than Windows targets.
+
+You can also use this to test platforms with different properties than your host
+platform. For example `cargo miri test --target mips64-unknown-linux-gnuabi64`
+will run your test suite on a big-endian target, which is useful for testing
+endian-sensitive code.
+
+### Running Miri on CI
+
+To run Miri on CI, make sure that you handle the case where the latest nightly
+does not ship the Miri component because it currently does not build. `rustup
+toolchain install --component` knows how to handle this situation, so the
+following snippet should always work:
+
+```sh
+rustup toolchain install nightly --component miri
+rustup override set nightly
+
+cargo miri test
+```
+
+Here is an example job for GitHub Actions:
+
+```yaml
+  miri:
+    name: "Miri"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install Miri
+        run: |
+          rustup toolchain install nightly --component miri
+          rustup override set nightly
+          cargo miri setup
+      - name: Test with Miri
+        run: cargo miri test
+```
+
+The explicit `cargo miri setup` helps to keep the output of the actual test step
+clean.
+
+### Testing for alignment issues
+
+Miri can sometimes miss misaligned accesses since allocations can "happen to be"
+aligned just right. You can use `-Zmiri-symbolic-alignment-check` to definitely
+catch all such issues, but that flag will also cause false positives when code
+does manual pointer arithmetic to account for alignment. Another alternative is
+to call Miri with various values for `-Zmiri-seed`; that will alter the
+randomness that is used to determine allocation base addresses. The following
+snippet calls Miri in a loop with different values for the seed:
+
+```
+for SEED in $({ echo obase=16; seq 0 255; } | bc); do
+  echo "Trying seed: $SEED"
+  MIRIFLAGS=-Zmiri-seed=$SEED cargo miri test || { echo "Failing seed: $SEED"; break; };
+done
+```
+
+### Supported targets
+
+Miri does not support all targets supported by Rust. The good news, however, is
+that no matter your host OS/platform, it is easy to run code for *any* target
+using `--target`!
+
+The following targets are tested on CI and thus should always work (to the
+degree documented below):
+
+- The best-supported target is `x86_64-unknown-linux-gnu`. Miri releases are
+  blocked on things working with this target. Most other Linux targets should
+  also work well; we do run the test suite on `i686-unknown-linux-gnu` as a
+  32bit target and `mips64-unknown-linux-gnuabi64` as a big-endian target.
+- `x86_64-apple-darwin` should work basically as well as Linux. We also test
+  `aarch64-apple-darwin`. However, we might ship Miri with a nightly even when
+  some features on these targets regress.
+- `x86_64-pc-windows-msvc` works, but supports fewer features than the Linux and
+  Apple targets. For example, file system access and concurrency are not
+  supported on Windows. We also test `i686-pc-windows-msvc`, with the same
+  reduced feature set. We might ship Miri with a nightly even when some features
+  on these targets regress.
+
+### Common Problems
+
+When using the above instructions, you may encounter a number of confusing compiler
+errors.
+
+#### "note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace"
+
+You may see this when trying to get Miri to display a backtrace. By default, Miri
+doesn't expose any environment to the program, so running
+`RUST_BACKTRACE=1 cargo miri test` will not do what you expect.
+
+To get a backtrace, you need to disable isolation
+[using `-Zmiri-disable-isolation`][miri-flags]:
+
+```sh
+RUST_BACKTRACE=1 MIRIFLAGS="-Zmiri-disable-isolation" cargo miri test
+```
+
+#### "found possibly newer version of crate `std` which `<dependency>` depends on"
+
+Your build directory may contain artifacts from an earlier build that have/have
+not been built for Miri. Run `cargo clean` before switching from non-Miri to
+Miri builds and vice-versa.
+
+#### "found crate `std` compiled by an incompatible version of rustc"
+
+You may be running `cargo miri` with a different compiler version than the one
+used to build the custom libstd that Miri uses, and Miri failed to detect that.
+Try deleting `~/.cache/miri`.
+
+#### "no mir for `std::rt::lang_start_internal`"
+
+This means the sysroot you are using was not compiled with Miri in mind.  This
+should never happen when you use `cargo miri` because that takes care of setting
+up the sysroot.  If you are using `miri` (the Miri driver) directly, see the
+[contributors' guide](CONTRIBUTING.md) for how to use `./miri` to best do that.
+
+
+## Miri `-Z` flags and environment variables
+[miri-flags]: #miri--z-flags-and-environment-variables
+
+Miri adds its own set of `-Z` flags, which are usually set via the `MIRIFLAGS`
+environment variable. We first document the most relevant and most commonly used flags:
+
+* `-Zmiri-compare-exchange-weak-failure-rate=<rate>` changes the failure rate of
+  `compare_exchange_weak` operations. The default is `0.8` (so 4 out of 5 weak ops will fail).
+  You can change it to any value between `0.0` and `1.0`, where `1.0` means it
+  will always fail and `0.0` means it will never fail. Note than setting it to
+  `1.0` will likely cause hangs, since it means programs using
+  `compare_exchange_weak` cannot make progress.
+* `-Zmiri-disable-isolation` disables host isolation.  As a consequence,
+  the program has access to host resources such as environment variables, file
+  systems, and randomness.
+* `-Zmiri-isolation-error=<action>` configures Miri's response to operations
+  requiring host access while isolation is enabled. `abort`, `hide`, `warn`,
+  and `warn-nobacktrace` are the supported actions. The default is to `abort`,
+  which halts the machine. Some (but not all) operations also support continuing
+  execution with a "permission denied" error being returned to the program.
+  `warn` prints a full backtrace when that happens; `warn-nobacktrace` is less
+  verbose. `hide` hides the warning entirely.
+* `-Zmiri-env-forward=<var>` forwards the `var` environment variable to the interpreted program. Can
+  be used multiple times to forward several variables. Execution will still be deterministic if the
+  value of forwarded variables stays the same. Has no effect if `-Zmiri-disable-isolation` is set.
+* `-Zmiri-ignore-leaks` disables the memory leak checker, and also allows some
+  remaining threads to exist when the main thread exits.
+* `-Zmiri-permissive-provenance` disables the warning for integer-to-pointer casts and
+  [`ptr::from_exposed_addr`](https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html).
+  This will necessarily miss some bugs as those operations are not efficiently and accurately
+  implementable in a sanitizer, but it will only miss bugs that concern memory/pointers which is
+  subject to these operations.
+* `-Zmiri-preemption-rate` configures the probability that at the end of a basic block, the active
+  thread will be preempted. The default is `0.01` (i.e., 1%). Setting this to `0` disables
+  preemption.
+* `-Zmiri-report-progress` makes Miri print the current stacktrace every now and then, so you can
+  tell what it is doing when a program just keeps running. You can customize how frequently the
+  report is printed via `-Zmiri-report-progress=<blocks>`, which prints the report every N basic
+  blocks.
+* `-Zmiri-seed=<hex>` configures the seed of the RNG that Miri uses to resolve non-determinism. This
+  RNG is used to pick base addresses for allocations, to determine preemption and failure of
+  `compare_exchange_weak`, and to control store buffering for weak memory emulation. When isolation
+  is enabled (the default), this is also used to emulate system entropy. The default seed is 0. You
+  can increase test coverage by running Miri multiple times with different seeds.
+* `-Zmiri-strict-provenance` enables [strict
+  provenance](https://github.com/rust-lang/rust/issues/95228) checking in Miri. This means that
+  casting an integer to a pointer yields a result with 'invalid' provenance, i.e., with provenance
+  that cannot be used for any memory access.
+* `-Zmiri-symbolic-alignment-check` makes the alignment check more strict.  By default, alignment is
+  checked by casting the pointer to an integer, and making sure that is a multiple of the alignment.
+  This can lead to cases where a program passes the alignment check by pure chance, because things
+  "happened to be" sufficiently aligned -- there is no UB in this execution but there would be UB in
+  others.  To avoid such cases, the symbolic alignment check only takes into account the requested
+  alignment of the relevant allocation, and the offset into that allocation.  This avoids missing
+  such bugs, but it also incurs some false positives when the code does manual integer arithmetic to
+  ensure alignment.  (The standard library `align_to` method works fine in both modes; under
+  symbolic alignment it only fills the middle slice when the allocation guarantees sufficient
+  alignment.)
+* `-Zmiri-tag-gc=<blocks>` configures how often the pointer tag garbage collector runs. The default
+  is to search for and remove unreachable tags once every `10,000` basic blocks. Setting this to
+  `0` disables the garbage collector, which causes some programs to have explosive memory usage
+  and/or super-linear runtime.
+
+The remaining flags are for advanced use only, and more likely to change or be removed.
+Some of these are **unsound**, which means they can lead
+to Miri failing to detect cases of undefined behavior in a program.
+
+* `-Zmiri-disable-abi-check` disables checking [function ABI]. Using this flag
+  is **unsound**.
+* `-Zmiri-disable-alignment-check` disables checking pointer alignment, so you
+  can focus on other failures, but it means Miri can miss bugs in your program.
+  Using this flag is **unsound**.
+* `-Zmiri-disable-data-race-detector` disables checking for data races.  Using
+  this flag is **unsound**. This implies `-Zmiri-disable-weak-memory-emulation`.
+* `-Zmiri-disable-stacked-borrows` disables checking the experimental
+  [Stacked Borrows] aliasing rules.  This can make Miri run faster, but it also
+  means no aliasing violations will be detected.  Using this flag is **unsound**
+  (but the affected soundness rules are experimental).
+* `-Zmiri-disable-validation` disables enforcing validity invariants, which are
+  enforced by default.  This is mostly useful to focus on other failures (such
+  as out-of-bounds accesses) first.  Setting this flag means Miri can miss bugs
+  in your program.  However, this can also help to make Miri run faster.  Using
+  this flag is **unsound**.
+* `-Zmiri-disable-weak-memory-emulation` disables the emulation of some C++11 weak
+  memory effects.
+* `-Zmiri-extern-so-file=<path to a shared object file>` is an experimental flag for providing support
+  for FFI calls. Functions not provided by that file are still executed via the usual Miri shims.
+  **WARNING**: If an invalid/incorrect `.so` file is specified, this can cause undefined behaviour in Miri itself!
+  And of course, Miri cannot do any checks on the actions taken by the external code.
+  Note that Miri has its own handling of file descriptors, so if you want to replace *some* functions
+  working on file descriptors, you will have to replace *all* of them, or the two kinds of
+  file descriptors will be mixed up.
+  This is **work in progress**; currently, only integer arguments and return values are
+  supported (and no, pointer/integer casts to work around this limitation will not work;
+  they will fail horribly). It also only works on unix hosts for now.
+  Follow [the discussion on supporting other types](https://github.com/rust-lang/miri/issues/2365). 
+* `-Zmiri-measureme=<name>` enables `measureme` profiling for the interpreted program.
+   This can be used to find which parts of your program are executing slowly under Miri.
+   The profile is written out to a file with the prefix `<name>`, and can be processed
+   using the tools in the repository https://github.com/rust-lang/measureme.
+* `-Zmiri-mute-stdout-stderr` silently ignores all writes to stdout and stderr,
+  but reports to the program that it did actually write. This is useful when you
+  are not interested in the actual program's output, but only want to see Miri's
+  errors and warnings.
+* `-Zmiri-panic-on-unsupported` will makes some forms of unsupported functionality,
+  such as FFI and unsupported syscalls, panic within the context of the emulated
+  application instead of raising an error within the context of Miri (and halting
+  execution). Note that code might not expect these operations to ever panic, so
+  this flag can lead to strange (mis)behavior.
+* `-Zmiri-retag-fields` changes Stacked Borrows retagging to recurse into fields.
+  This means that references in fields of structs/enums/tuples/arrays/... are retagged,
+  and in particular, they are protected when passed as function arguments.
+* `-Zmiri-track-alloc-id=<id1>,<id2>,...` shows a backtrace when the given allocations are
+  being allocated or freed.  This helps in debugging memory leaks and
+  use after free bugs. Specifying this argument multiple times does not overwrite the previous
+  values, instead it appends its values to the list. Listing an id multiple times has no effect.
+* `-Zmiri-track-call-id=<id1>,<id2>,...` shows a backtrace when the given call ids are
+  assigned to a stack frame.  This helps in debugging UB related to Stacked
+  Borrows "protectors". Specifying this argument multiple times does not overwrite the previous
+  values, instead it appends its values to the list. Listing an id multiple times has no effect.
+* `-Zmiri-track-pointer-tag=<tag1>,<tag2>,...` shows a backtrace when a given pointer tag
+  is created and when (if ever) it is popped from a borrow stack (which is where the tag becomes invalid 
+  and any future use of it will error).  This helps you in finding out why UB is
+  happening and where in your code would be a good place to look for it.
+  Specifying this argument multiple times does not overwrite the previous
+  values, instead it appends its values to the list. Listing a tag multiple times has no effect.
+* `-Zmiri-track-weak-memory-loads` shows a backtrace when weak memory emulation returns an outdated
+  value from a load. This can help diagnose problems that disappear under
+  `-Zmiri-disable-weak-memory-emulation`.
+
+[function ABI]: https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier
+
+Some native rustc `-Z` flags are also very relevant for Miri:
+
+* `-Zmir-opt-level` controls how many MIR optimizations are performed.  Miri
+  overrides the default to be `0`; be advised that using any higher level can
+  make Miri miss bugs in your program because they got optimized away.
+* `-Zalways-encode-mir` makes rustc dump MIR even for completely monomorphic
+  functions.  This is needed so that Miri can execute such functions, so Miri
+  sets this flag per default.
+* `-Zmir-emit-retag` controls whether `Retag` statements are emitted. Miri
+  enables this per default because it is needed for [Stacked Borrows].
+
+Moreover, Miri recognizes some environment variables:
+
+* `MIRI_AUTO_OPS` indicates whether the automatic execution of rustfmt, clippy and rustup-toolchain
+  should be skipped. If it is set to any value, they are skipped. This is used for avoiding
+  infinite recursion in `./miri` and to allow automated IDE actions to avoid the auto ops.
+* `MIRI_LOG`, `MIRI_BACKTRACE` control logging and backtrace printing during
+  Miri executions, also [see "Testing the Miri driver" in `CONTRIBUTING.md`][testing-miri].
+* `MIRIFLAGS` (recognized by `cargo miri` and the test suite) defines extra
+  flags to be passed to Miri.
+* `MIRI_LIB_SRC` defines the directory where Miri expects the sources of the
+  standard library that it will build and use for interpretation. This directory
+  must point to the `library` subdirectory of a `rust-lang/rust` repository
+  checkout. Note that changing files in that directory does not automatically
+  trigger a re-build of the standard library; you have to clear the Miri build
+  cache manually (on Linux, `rm -rf ~/.cache/miri`).
+* `MIRI_SYSROOT` (recognized by `cargo miri` and the Miri driver) indicates the sysroot to use. When
+  using `cargo miri`, only set this if you do not want to use the automatically created sysroot. For
+  directly invoking the Miri driver, this variable (or a `--sysroot` flag) is mandatory.
+* `MIRI_TEST_TARGET` (recognized by the test suite and the `./miri` script) indicates which target
+  architecture to test against.  `miri` and `cargo miri` accept the `--target` flag for the same
+  purpose.
+* `MIRI_NO_STD` (recognized by `cargo miri` and the test suite) makes sure that the target's
+  sysroot is built without libstd. This allows testing and running no_std programs.
+* `MIRI_BLESS` (recognized by the test suite) overwrite all `stderr` and `stdout` files
+  instead of checking whether the output matches.
+* `MIRI_SKIP_UI_CHECKS` (recognized by the test suite) don't check whether the
+  `stderr` or `stdout` files match the actual output. Useful for the rustc test suite
+  which has subtle differences that we don't care about.
+
+The following environment variables are *internal* and must not be used by
+anyone but Miri itself. They are used to communicate between different Miri
+binaries, and as such worth documenting:
+
+* `MIRI_BE_RUSTC` can be set to `host` or `target`. It tells the Miri driver to
+  actually not interpret the code but compile it like rustc would. With `target`, Miri sets
+  some compiler flags to prepare the code for interpretation; with `host`, this is not done.
+  This environment variable is useful to be sure that the compiled `rlib`s are compatible
+  with Miri.
+* `MIRI_CALLED_FROM_XARGO` is set during the Miri-induced `xargo` sysroot build,
+  which will re-invoke `cargo-miri` as the `rustc` to use for this build.
+* `MIRI_CALLED_FROM_RUSTDOC` when set to any value tells `cargo-miri` that it is
+  running as a child process of `rustdoc`, which invokes it twice for each doc-test
+  and requires special treatment, most notably a check-only build before interpretation.
+  This is set by `cargo-miri` itself when running as a `rustdoc`-wrapper.
+* `MIRI_CWD` when set to any value tells the Miri driver to change to the given
+  directory after loading all the source files, but before commencing
+  interpretation. This is useful if the interpreted program wants a different
+  working directory at run-time than at build-time.
+* `MIRI_LOCAL_CRATES` is set by `cargo-miri` to tell the Miri driver which
+  crates should be given special treatment in diagnostics, in addition to the
+  crate currently being compiled.
+* `MIRI_VERBOSE` when set to any value tells the various `cargo-miri` phases to
+  perform verbose logging.
+* `MIRI_HOST_SYSROOT` is set by bootstrap to tell `cargo-miri` which sysroot to use for *host*
+  operations.
+
+[testing-miri]: CONTRIBUTING.md#testing-the-miri-driver
+
+## Miri `extern` functions
+
+Miri provides some `extern` functions that programs can import to access
+Miri-specific functionality:
+
+```rust
+#[cfg(miri)]
+extern "Rust" {
+    /// Miri-provided extern function to mark the block `ptr` points to as a "root"
+    /// for some static memory. This memory and everything reachable by it is not
+    /// considered leaking even if it still exists when the program terminates.
+    ///
+    /// `ptr` has to point to the beginning of an allocated block.
+    fn miri_static_root(ptr: *const u8);
+
+    // Miri-provided extern function to get the amount of frames in the current backtrace.
+    // The `flags` argument must be `0`.
+    fn miri_backtrace_size(flags: u64) -> usize;
+
+    /// Miri-provided extern function to obtain a backtrace of the current call stack.
+    /// This writes a slice of pointers into `buf` - each pointer is an opaque value
+    /// that is only useful when passed to `miri_resolve_frame`.
+    /// `buf` must have `miri_backtrace_size(0) * pointer_size` bytes of space.
+    /// The `flags` argument must be `1`.
+    fn miri_get_backtrace(flags: u64, buf: *mut *mut ());
+
+    /// Miri-provided extern function to resolve a frame pointer obtained
+    /// from `miri_get_backtrace`. The `flags` argument must be `1`,
+    /// and `MiriFrame` should be declared as follows:
+    ///
+    /// ```rust
+    /// #[repr(C)]
+    /// struct MiriFrame {
+    ///     // The size of the name of the function being executed, encoded in UTF-8
+    ///     name_len: usize,
+    ///     // The size of filename of the function being executed, encoded in UTF-8
+    ///     filename_len: usize,
+    ///     // The line number currently being executed in `filename`, starting from '1'.
+    ///     lineno: u32,
+    ///     // The column number currently being executed in `filename`, starting from '1'.
+    ///     colno: u32,
+    ///     // The function pointer to the function currently being executed.
+    ///     // This can be compared against function pointers obtained by
+    ///     // casting a function (e.g. `my_fn as *mut ()`)
+    ///     fn_ptr: *mut ()
+    /// }
+    /// ```
+    ///
+    /// The fields must be declared in exactly the same order as they appear in `MiriFrame` above.
+    /// This function can be called on any thread (not just the one which obtained `frame`).
+    fn miri_resolve_frame(frame: *mut (), flags: u64) -> MiriFrame;
+
+    /// Miri-provided extern function to get the name and filename of the frame provided by `miri_resolve_frame`.
+    /// `name_buf` and `filename_buf` should be allocated with the `name_len` and `filename_len` fields of `MiriFrame`.
+    /// The flags argument must be `0`.
+    fn miri_resolve_frame_names(ptr: *mut (), flags: u64, name_buf: *mut u8, filename_buf: *mut u8);
+
+    /// Miri-provided extern function to begin unwinding with the given payload.
+    ///
+    /// This is internal and unstable and should not be used; we give it here
+    /// just to be complete.
+    fn miri_start_panic(payload: *mut u8) -> !;
+}
+```
+
+## Contributing and getting help
+
+If you want to contribute to Miri, great!  Please check out our
+[contribution guide](CONTRIBUTING.md).
+
+For help with running Miri, you can open an issue here on
+GitHub or use the [Miri stream on the Rust Zulip][zulip].
+
+[zulip]: https://rust-lang.zulipchat.com/#narrow/stream/269128-miri
+
+## History
+
+This project began as part of an undergraduate research course in 2015 by
+@solson at the [University of Saskatchewan][usask].  There are [slides] and a
+[report] available from that project.  In 2016, @oli-obk joined to prepare Miri
+for eventually being used as const evaluator in the Rust compiler itself
+(basically, for `const` and `static` stuff), replacing the old evaluator that
+worked directly on the AST.  In 2017, @RalfJung did an internship with Mozilla
+and began developing Miri towards a tool for detecting undefined behavior, and
+also using Miri as a way to explore the consequences of various possible
+definitions for undefined behavior in Rust.  @oli-obk's move of the Miri engine
+into the compiler finally came to completion in early 2018.  Meanwhile, later
+that year, @RalfJung did a second internship, developing Miri further with
+support for checking basic type invariants and verifying that references are
+used according to their aliasing restrictions.
+
+[usask]: https://www.usask.ca/
+[slides]: https://solson.me/miri-slides.pdf
+[report]: https://solson.me/miri-report.pdf
+
+## Bugs found by Miri
+
+Miri has already found a number of bugs in the Rust standard library and beyond, which we collect here.
+
+Definite bugs found:
+
+* [`Debug for vec_deque::Iter` accessing uninitialized memory](https://github.com/rust-lang/rust/issues/53566)
+* [`Vec::into_iter` doing an unaligned ZST read](https://github.com/rust-lang/rust/pull/53804)
+* [`From<&[T]> for Rc` creating a not sufficiently aligned reference](https://github.com/rust-lang/rust/issues/54908)
+* [`BTreeMap` creating a shared reference pointing to a too small allocation](https://github.com/rust-lang/rust/issues/54957)
+* [`Vec::append` creating a dangling reference](https://github.com/rust-lang/rust/pull/61082)
+* [Futures turning a shared reference into a mutable one](https://github.com/rust-lang/rust/pull/56319)
+* [`str` turning a shared reference into a mutable one](https://github.com/rust-lang/rust/pull/58200)
+* [`rand` performing unaligned reads](https://github.com/rust-random/rand/issues/779)
+* [The Unix allocator calling `posix_memalign` in an invalid way](https://github.com/rust-lang/rust/issues/62251)
+* [`getrandom` calling the `getrandom` syscall in an invalid way](https://github.com/rust-random/getrandom/pull/73)
+* [`Vec`](https://github.com/rust-lang/rust/issues/69770) and [`BTreeMap`](https://github.com/rust-lang/rust/issues/69769) leaking memory under some (panicky) conditions
+* [`beef` leaking memory](https://github.com/maciejhirsz/beef/issues/12)
+* [`EbrCell` using uninitialized memory incorrectly](https://github.com/Firstyear/concread/commit/b15be53b6ec076acb295a5c0483cdb4bf9be838f#diff-6282b2fc8e98bd089a1f0c86f648157cR229)
+* [TiKV performing an unaligned pointer access](https://github.com/tikv/tikv/issues/7613)
+* [`servo_arc` creating a dangling shared reference](https://github.com/servo/servo/issues/26357)
+* [TiKV constructing out-of-bounds pointers (and overlapping mutable references)](https://github.com/tikv/tikv/pull/7751)
+* [`encoding_rs` doing out-of-bounds pointer arithmetic](https://github.com/hsivonen/encoding_rs/pull/53)
+* [TiKV using `Vec::from_raw_parts` incorrectly](https://github.com/tikv/agatedb/pull/24)
+* Incorrect doctests for [`AtomicPtr`](https://github.com/rust-lang/rust/pull/84052) and [`Box::from_raw_in`](https://github.com/rust-lang/rust/pull/84053)
+* [Insufficient alignment in `ThinVec`](https://github.com/Gankra/thin-vec/pull/27)
+* [`crossbeam-epoch` calling `assume_init` on a partly-initialized `MaybeUninit`](https://github.com/crossbeam-rs/crossbeam/pull/779)
+* [`integer-encoding` dereferencing a misaligned pointer](https://github.com/dermesser/integer-encoding-rs/pull/23)
+* [`rkyv` constructing a `Box<[u8]>` from an overaligned allocation](https://github.com/rkyv/rkyv/commit/a9417193a34757e12e24263178be8b2eebb72456)
+* [Data race in `thread::scope`](https://github.com/rust-lang/rust/issues/98498)
+* [`regex` incorrectly handling unaligned `Vec<u8>` buffers](https://www.reddit.com/r/rust/comments/vq3mmu/comment/ienc7t0?context=3)
+* [Incorrect use of `compare_exchange_weak` in `once_cell`](https://github.com/matklad/once_cell/issues/186)
+
+Violations of [Stacked Borrows] found that are likely bugs (but Stacked Borrows is currently just an experiment):
+
+* [`VecDeque::drain` creating overlapping mutable references](https://github.com/rust-lang/rust/pull/56161)
+* Various `BTreeMap` problems
+    * [`BTreeMap` iterators creating mutable references that overlap with shared references](https://github.com/rust-lang/rust/pull/58431)
+    * [`BTreeMap::iter_mut` creating overlapping mutable references](https://github.com/rust-lang/rust/issues/73915)
+    * [`BTreeMap` node insertion using raw pointers outside their valid memory area](https://github.com/rust-lang/rust/issues/78477)
+* [`LinkedList` cursor insertion creating overlapping mutable references](https://github.com/rust-lang/rust/pull/60072)
+* [`Vec::push` invalidating existing references into the vector](https://github.com/rust-lang/rust/issues/60847)
+* [`align_to_mut` violating uniqueness of mutable references](https://github.com/rust-lang/rust/issues/68549)
+* [`sized-chunks` creating aliasing mutable references](https://github.com/bodil/sized-chunks/issues/8)
+* [`String::push_str` invalidating existing references into the string](https://github.com/rust-lang/rust/issues/70301)
+* [`ryu` using raw pointers outside their valid memory area](https://github.com/dtolnay/ryu/issues/24)
+* [ink! creating overlapping mutable references](https://github.com/rust-lang/miri/issues/1364)
+* [TiKV creating overlapping mutable reference and raw pointer](https://github.com/tikv/tikv/pull/7709)
+* [Windows `Env` iterator using a raw pointer outside its valid memory area](https://github.com/rust-lang/rust/pull/70479)
+* [`VecDeque::iter_mut` creating overlapping mutable references](https://github.com/rust-lang/rust/issues/74029)
+* [Various standard library aliasing issues involving raw pointers](https://github.com/rust-lang/rust/pull/78602)
+* [`<[T]>::copy_within` using a loan after invalidating it](https://github.com/rust-lang/rust/pull/85610)
+
+## Scientific papers employing Miri
+
+* [Stacked Borrows: An Aliasing Model for Rust](https://plv.mpi-sws.org/rustbelt/stacked-borrows/)
+* [Using Lightweight Formal Methods to Validate a Key-Value Storage Node in Amazon S3](https://www.amazon.science/publications/using-lightweight-formal-methods-to-validate-a-key-value-storage-node-in-amazon-s3)
+* [SyRust: Automatic Testing of Rust Libraries with Semantic-Aware Program Synthesis](https://dl.acm.org/doi/10.1145/3453483.3454084)
+
+## License
+
+Licensed under either of
+
+  * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
+    http://www.apache.org/licenses/LICENSE-2.0)
+  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+    http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you shall be dual licensed as above, without any
+additional terms or conditions.
diff --git a/src/tools/miri/bench-cargo-miri/backtraces/Cargo.lock b/src/tools/miri/bench-cargo-miri/backtraces/Cargo.lock
new file mode 100644
index 000000000000..375b129a7e59
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/backtraces/Cargo.lock
@@ -0,0 +1,94 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "addr2line"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9ecd88a8c8378ca913a680cd98f0f13ac67383d35993f86c90a70e3f137816b"
+dependencies = [
+ "gimli",
+]
+
+[[package]]
+name = "adler"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
+
+[[package]]
+name = "backtrace"
+version = "0.3.65"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11a17d453482a265fd5f8479f2a3f405566e6ca627837aaddb85af8b1ab8ef61"
+dependencies = [
+ "addr2line",
+ "cc",
+ "cfg-if",
+ "libc",
+ "miniz_oxide",
+ "object",
+ "rustc-demangle",
+]
+
+[[package]]
+name = "backtraces"
+version = "0.1.0"
+dependencies = [
+ "backtrace",
+]
+
+[[package]]
+name = "cc"
+version = "1.0.73"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "gimli"
+version = "0.26.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78cc372d058dcf6d5ecd98510e7fbc9e5aec4d21de70f65fea8fecebcd881bd4"
+
+[[package]]
+name = "libc"
+version = "0.2.126"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
+
+[[package]]
+name = "memchr"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
+
+[[package]]
+name = "miniz_oxide"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f5c75688da582b8ffc1f1799e9db273f32133c49e048f614d22ec3256773ccc"
+dependencies = [
+ "adler",
+]
+
+[[package]]
+name = "object"
+version = "0.28.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e42c982f2d955fac81dd7e1d0e1426a7d702acd9c98d19ab01083a6a0328c424"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "rustc-demangle"
+version = "0.1.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ef03e0a2b150c7a90d01faf6254c9c48a41e95fb2a8c2ac1c6f0d2b9aefc342"
diff --git a/src/tools/miri/bench-cargo-miri/backtraces/Cargo.toml b/src/tools/miri/bench-cargo-miri/backtraces/Cargo.toml
new file mode 100644
index 000000000000..1ba96b19395d
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/backtraces/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "backtraces"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+backtrace = "0.3.65"
diff --git a/src/tools/miri/bench-cargo-miri/backtraces/src/main.rs b/src/tools/miri/bench-cargo-miri/backtraces/src/main.rs
new file mode 100644
index 000000000000..eba51c60dbc5
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/backtraces/src/main.rs
@@ -0,0 +1,29 @@
+//! Extracted from the backtrace crate's test test_frame_conversion
+
+use backtrace::{Backtrace, BacktraceFrame};
+use std::fmt::Write;
+
+fn main() {
+    let mut frames = vec![];
+    backtrace::trace(|frame| {
+        let converted = BacktraceFrame::from(frame.clone());
+        frames.push(converted);
+        true
+    });
+
+    let mut manual = Backtrace::from(frames);
+    manual.resolve();
+    let frames = manual.frames();
+
+    let mut output = String::new();
+    for frame in frames {
+        // Originally these were println! but we'd prefer our benchmarks to not emit a lot of
+        // output to stdout/stderr. Unfortunately writeln! to a String is faster, but we still
+        // manage to exercise interesting code paths in Miri.
+        writeln!(output, "{:?}", frame.ip()).unwrap();
+        writeln!(output, "{:?}", frame.symbol_address()).unwrap();
+        writeln!(output, "{:?}", frame.module_base_address()).unwrap();
+        writeln!(output, "{:?}", frame.symbols()).unwrap();
+    }
+    drop(output);
+}
diff --git a/src/tools/miri/bench-cargo-miri/mse/Cargo.lock b/src/tools/miri/bench-cargo-miri/mse/Cargo.lock
new file mode 100644
index 000000000000..d2b1aa341bbb
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/mse/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "mse"
+version = "0.1.0"
diff --git a/src/tools/miri/bench-cargo-miri/mse/Cargo.toml b/src/tools/miri/bench-cargo-miri/mse/Cargo.toml
new file mode 100644
index 000000000000..7b4c2dc758fa
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/mse/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "mse"
+version = "0.1.0"
+authors = ["Ralf Jung <post@ralfj.de>"]
+edition = "2018"
+
+[dependencies]
diff --git a/src/tools/miri/bench-cargo-miri/mse/src/main.rs b/src/tools/miri/bench-cargo-miri/mse/src/main.rs
new file mode 100644
index 000000000000..c09dc2484d38
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/mse/src/main.rs
@@ -0,0 +1,32 @@
+#[rustfmt::skip] // no need to wrap these arrays onto hundreds of lines
+static EXPECTED: &[u8] = &[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 0, 0, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 1, 0, 255, 255, 1, 0, 255, 255, 1, 0, 255, 255, 1, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 254, 255, 0, 0, 254, 255, 0, 0, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 255, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 255, 255, 1, 0, 255, 255, 1, 0, 0, 0, 1, 0, 255, 255, 2, 0, 255, 255, 2, 0, 255, 255, 2, 0, 255, 255, 2, 0, 255, 255, 2, 0, 255, 255, 1, 0, 255, 255, 1, 0, 255, 255, 0, 0, 254, 255, 0, 0, 254, 255, 0, 0, 254, 255, 255, 255, 254, 255, 254, 255, 254, 255, 253, 255, 253, 255, 253, 255, 253, 255, 252, 255, 254, 255, 251, 255, 254, 255, 251, 255, 254, 255, 252, 255, 255, 255, 252, 255, 0, 0, 252, 255, 0, 0, 252, 255, 1, 0, 252, 255, 1, 0, 252, 255, 2, 0, 252, 255, 2, 0, 252, 255, 2, 0, 252, 255, 2, 0, 252, 255, 2, 0, 253, 255, 1, 0, 252, 255, 0, 0, 252, 255, 255, 255, 251, 255, 0, 0, 251, 255, 0, 0, 251, 255, 0, 0, 252, 255, 2, 0, 252, 255, 3, 0, 252, 255, 4, 0, 253, 255, 5, 0, 254, 255, 5, 0, 253, 255, 6, 0, 253, 255, 6, 0, 253, 255, 5, 0, 253, 255, 5, 0, 254, 255, 4, 0, 254, 255, 3, 0, 251, 255, 0, 0, 250, 255, 255, 255, 253, 255, 254, 255, 252, 255, 252, 255, 247, 255, 251, 255, 247, 255, 252, 255, 252, 255, 254, 255, 252, 255, 254, 255, 252, 255, 255, 255, 254, 255, 1, 0, 1, 0, 1, 0, 4, 0, 2, 0, 8, 0, 2, 0, 12, 0, 1, 0, 13, 0, 0, 0, 12, 0, 0, 0, 11, 0, 255, 255, 8, 0, 254, 255, 7, 0, 0, 0, 7, 0, 253, 255, 11, 0, 248, 255, 15, 0, 247, 255, 17, 0, 250, 255, 17, 0, 251, 255, 13, 0, 253, 255, 7, 0, 255, 255, 3, 0, 255, 255, 254, 255, 255, 255, 252, 255, 255, 255, 252, 255, 254, 255, 250, 255, 255, 255, 242, 255, 254, 255, 239, 255, 252, 255, 248, 255, 255, 255, 249, 255, 5, 0, 239, 255, 7, 0, 238, 255, 10, 0, 249, 255, 18, 0, 254, 255, 25, 0, 253, 255, 27, 0, 0, 0, 31, 0, 4, 0, 34, 0, 4, 0, 34, 0, 8, 0, 36, 0, 8, 0, 37, 0, 2, 0, 36, 0, 4, 0, 34, 0, 8, 0, 28, 0, 3, 0, 15, 0, 255, 255, 11, 0, 0, 0, 12, 0, 251, 255, 8, 0, 252, 255, 10, 0, 0, 0, 23, 0, 252, 255, 31, 0, 248, 255, 30, 0, 254, 255, 30, 0, 255, 255, 26, 0, 250, 255, 22, 0, 250, 255, 20, 0, 244, 255, 15, 0, 237, 255, 10, 0, 246, 255, 13, 0, 242, 255, 6, 0, 213, 255, 243, 255, 213, 255, 240, 255, 247, 255, 244, 255, 246, 255, 227, 255, 214, 255, 216, 255, 219, 255, 228, 255, 251, 255, 235, 255, 1, 0, 232, 255, 248, 255, 236, 255, 4, 0, 238, 255, 26, 0, 232, 255, 44, 0, 230, 255, 66, 0, 226, 255, 86, 0, 219, 255, 88, 0, 215, 255, 72, 0, 210, 255, 50, 0, 225, 255, 28, 0, 23, 0, 14, 0, 64, 0, 16, 0, 51, 0, 26, 0, 32, 0, 34, 0, 39, 0, 42, 0, 48, 0, 35, 0, 58, 0, 255, 255, 72, 0, 220, 255, 69, 0, 197, 255, 58, 0, 158, 255, 54, 0, 132, 255, 36, 0, 153, 255, 12, 0, 146, 255, 5, 0, 83, 255, 237, 255, 110, 255, 197, 255, 252, 255, 214, 255, 51, 0, 1, 0, 233, 255, 250, 255, 226, 255, 250, 255, 45, 0, 46, 0, 47, 0, 70, 0, 6, 0, 55, 0, 19, 0, 60, 0, 38, 0, 62, 0, 42, 0, 47, 0, 61, 0, 46, 0, 40, 0, 42, 0, 237, 255, 22, 0, 222, 255, 6, 0, 221, 255, 206, 255, 195, 255, 115, 255, 219, 255, 85, 255, 17, 0, 93, 255, 26, 0, 76, 255, 46, 0, 102, 255, 80, 0, 193, 255, 48, 0, 252, 255, 18, 0, 20, 0, 50, 0, 47, 0, 58, 0, 53, 0, 44, 0, 61, 0, 57, 0, 85, 0, 37, 0, 80, 0, 0, 0, 86, 0, 248, 255, 106, 0, 161, 255, 49, 0, 43, 255, 248, 255, 125, 255, 47, 0, 49, 0, 63, 0, 40, 0, 217, 255, 187, 255, 182, 255, 219, 255, 236, 255, 63, 0, 244, 255, 58, 0, 242, 255, 244, 255, 25, 0, 225, 255, 41, 0, 11, 0, 45, 0, 76, 0, 47, 0, 167, 0, 5, 0, 5, 1, 219, 255, 21, 1, 173, 255, 183, 0, 84, 255, 35, 0, 134, 255, 177, 255, 138, 0, 186, 255, 10, 1, 69, 0, 124, 0, 228, 0, 0, 0, 135, 1, 227, 255, 82, 2, 172, 255, 190, 2, 178, 255, 115, 2, 248, 255, 39, 2, 243, 255, 253, 1, 13, 0, 116, 1, 120, 0, 96, 1, 125, 0, 110, 2, 127, 0, 179, 2, 223, 0, 106, 1, 126, 0, 130, 1, 223, 255, 147, 3, 198, 0, 190, 3, 201, 1, 200, 1, 42, 1, 244, 1, 233, 0, 3, 4, 213, 1, 72, 4, 170, 1, 150, 3, 160, 0, 43, 4, 141, 0, 196, 4, 189, 0, 221, 4, 164, 0, 95, 5, 41, 1, 98, 5, 247, 1, 19, 5, 190, 2, 14, 6, 161, 3, 7, 7, 87, 3, 216, 6, 35, 2, 38, 7, 90, 2, 136, 7, 64, 3, 200, 6, 28, 3, 199, 6, 165, 3, 169, 7, 105, 5, 143, 7, 26, 6, 57, 8, 205, 5, 156, 10, 169, 5, 132, 11, 25, 5, 208, 10, 181, 4, 156, 10, 66, 5, 227, 9, 170, 5, 166, 9, 117, 6, 45, 12, 63, 8, 42, 13, 128, 8, 136, 10, 155, 7, 109, 11, 1, 9, 6, 15, 98, 10, 121, 9, 136, 8, 147, 252, 189, 7, 43, 247, 63, 10, 147, 249, 92, 11, 172, 248, 172, 10, 112, 245, 137, 11, 76, 246, 44, 12, 184, 247, 138, 11, 118, 246, 144, 12, 94, 246, 171, 13, 112, 247, 162, 12, 168, 246, 33, 13, 63, 246, 29, 15, 226, 247, 188, 14, 190, 248, 75, 15, 238, 247, 86, 17, 19, 247, 118, 11, 10, 247, 232, 254, 238, 247, 30, 249, 56, 248, 124, 250, 6, 247, 1, 250, 161, 246, 3, 249, 81, 247, 117, 250, 60, 247, 202, 250, 212, 247, 60, 250, 15, 249, 140, 250, 34, 248, 221, 249, 105, 247, 218, 249, 205, 248, 113, 251, 138, 248, 90, 250, 41, 248, 230, 248];
+#[rustfmt::skip]
+static PCM: &[i16] = &[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, -2, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 1, 0, 1, 0, 0, -2, 0, -2, 0, -2, 0, -2, -2, -2, -3, -3, -3, -3, -4, -2, -5, -2, -5, -2, -4, 0, -4, 0, -4, 0, -4, 1, -4, 1, -4, 2, -4, 2, -4, 2, -4, 2, -4, 2, -3, 1, -4, 0, -4, 0, -5, 0, -5, 0, -5, 0, -4, 2, -4, 3, -4, 4, -3, 5, -2, 5, -3, 6, -3, 6, -3, 5, -3, 5, -2, 4, -2, 3, -5, 0, -6, 0, -3, -2, -4, -4, -9, -5, -9, -4, -4, -2, -4, -2, -4, 0, -2, 1, 1, 1, 4, 2, 8, 2, 12, 1, 13, 0, 12, 0, 11, 0, 8, -2, 7, 0, 7, -3, 11, -8, 15, -9, 17, -6, 17, -5, 13, -3, 7, 0, 3, 0, -2, 0, -4, 0, -4, -2, -6, 0, -14, -2, -17, -4, -8, 0, -7, 5, -17, 7, -18, 10, -7, 18, -2, 25, -3, 27, 0, 31, 4, 34, 4, 34, 8, 36, 8, 37, 2, 36, 4, 34, 8, 28, 3, 15, 0, 11, 0, 12, -5, 8, -4, 10, 0, 23, -4, 31, -8, 30, -2, 30, 0, 26, -6, 22, -6, 20, -12, 15, -19, 10, -10, 13, -14, 6, -43, -13, -43, -16, -9, -12, -10, -29, -42, -40, -37, -28, -5, -21, 1, -24, -8, -20, 4, -18, 26, -24, 44, -26, 66, -30, 86, -37, 88, -41, 72, -46, 50, -31, 28, 23, 14, 64, 16, 51, 26, 32, 34, 39, 42, 48, 35, 58, 0, 72, -36, 69, -59, 58, -98, 54, -124, 36, -103, 12, -110, 5, -173, -19, -146, -59, -4, -42, 51, 1, -23, -6, -30, -6, 45, 46, 47, 70, 6, 55, 19, 60, 38, 62, 42, 47, 61, 46, 40, 42, -19, 22, -34, 6, -35, -50, -61, -141, -37, -171, 17, -163, 26, -180, 46, -154, 80, -63, 48, -4, 18, 20, 50, 47, 58, 53, 44, 61, 57, 85, 37, 80, 0, 86, -8, 106, -95, 49, -213, -8, -131, 47, 49, 63, 40, -39, -69, -74, -37, -20, 63, -12, 58, -14, -12, 25, -31, 41, 11, 45, 76, 47, 167, 5, 261, -37, 277, -83, 183, -172, 35, -122, -79, 138, -70, 266, 69, 124, 228, 0, 391, -29, 594, -84, 702, -78, 627, -8, 551, -13, 509, 13, 372, 120, 352, 125, 622, 127, 691, 223, 362, 126, 386, -33, 915, 198, 958, 457, 456, 298, 500, 233, 1027, 469, 1096, 426, 918, 160, 1067, 141, 1220, 189, 1245, 164, 1375, 297, 1378, 503, 1299, 702, 1550, 929, 1799, 855, 1752, 547, 1830, 602, 1928, 832, 1736, 796, 1735, 933, 1961, 1385, 1935, 1562, 2105, 1485, 2716, 1449, 2948, 1305, 2768, 1205, 2716, 1346, 2531, 1450, 2470, 1653, 3117, 2111, 3370, 2176, 2696, 1947, 2925, 2305, 3846, 2658, 2425, 2184, -877, 1981, -2261, 2623, -1645, 2908, -1876, 2732, -2704, 2953, -2484, 3116, -2120, 2954, -2442, 3216, -2466, 3499, -2192, 3234, -2392, 3361, -2497, 3869, -2078, 3772, -1858, 3915, -2066, 4438, -2285, 2934, -2294, -280, -2066, -1762, -1992, -1412, -2298, -1535, -2399, -1789, -2223, -1419, -2244, -1334, -2092, -1476, -1777, -1396, -2014, -1571, -2199, -1574, -1843, -1167, -1910, -1446, -2007, -1818];
+
+fn main() {
+    #[cfg(increase_thread_usage)]
+    let thread = std::thread::spawn(|| 4);
+
+    for _ in 0..2 {
+        mse(PCM.len(), PCM, EXPECTED);
+    }
+}
+
+fn read_i16(buffer: &[u8], index: usize) -> i16 {
+    const SIZE: usize = std::mem::size_of::<i16>();
+    let mut bytes: [u8; SIZE] = [0u8; SIZE];
+    bytes.copy_from_slice(&buffer[(index * SIZE)..(index * SIZE + SIZE)]);
+    unsafe { std::mem::transmute(bytes) }
+}
+
+fn mse(samples: usize, frame_buf: &[i16], buf_ref: &[u8]) -> f64 {
+    let mut mse = 0.0;
+    let max_samples = std::cmp::min(buf_ref.len() / 2, samples as usize);
+    for i in 0..max_samples {
+        let ref_res = read_i16(buf_ref, i);
+        let info_res = frame_buf[i as usize];
+        let diff = (ref_res - info_res).abs();
+        mse += f64::from(diff.pow(2));
+    }
+    mse / max_samples as f64
+}
diff --git a/src/tools/miri/bench-cargo-miri/serde1/Cargo.lock b/src/tools/miri/bench-cargo-miri/serde1/Cargo.lock
new file mode 100644
index 000000000000..487505761354
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/serde1/Cargo.lock
@@ -0,0 +1,89 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "cargo-miri-test"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "itoa"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "112c678d4050afce233f4f2852bb2eb519230b3cf12f33585275537d7e41578d"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c54b25569025b7fc9651de43004ae593a75ad88543b17178aa5e1b9c4f15f56f"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3f6f92acf49d1b98f7a81226834412ada05458b7364277387724a237f062695"
+
+[[package]]
+name = "serde"
+version = "1.0.137"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61ea8d54c77f8315140a05f4c7237403bf38b72704d031543aa1d16abbf517d1"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.137"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f26faba0c3959972377d3b2d306ee9f71faee9714294e41bb777f83f88578be"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b7ce2b32a1aed03c558dc61a5cd328f15aff2dbc17daad8fb8af04d2100e15c"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.96"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0748dd251e24453cb8717f0354206b91557e4ec8703673a4b30208f2abaf1ebf"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d22af068fba1eb5edcb4aea19d382b2a3deb4c8f9d475c589b6ada9e0fd493ee"
diff --git a/src/tools/miri/bench-cargo-miri/serde1/Cargo.toml b/src/tools/miri/bench-cargo-miri/serde1/Cargo.toml
new file mode 100644
index 000000000000..7cb863a7abf3
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/serde1/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "cargo-miri-test"
+version = "0.1.0"
+authors = ["Oliver Schneider <git-spam-no-reply9815368754983@oli-obk.de>"]
+edition = "2018"
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
diff --git a/src/tools/miri/bench-cargo-miri/serde1/src/main.rs b/src/tools/miri/bench-cargo-miri/serde1/src/main.rs
new file mode 100644
index 000000000000..2712156d61b4
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/serde1/src/main.rs
@@ -0,0 +1,13 @@
+static JSON: &str = r#"{"buffer":[-29,-42,-40,-37,-28,-5,-21,1,-24,-8,-20,4,-18,26,-24,44,-26,66,-30,86,-37,88,-41,72,-46,50,-31,28,23,14,64,16,51,26,32,34,39,42,48,35,58,0,72,-36,69,-59,58,-98,54,-124,36,-103,12,-110,5,-173,-19,-146,-59,-4,-42,51,1,-23,-6,-30,-6,45,46,47,70,6,55,19,60,38,62,42,47,61,46,40,42,-19,22,-34,6,-35,-50,-61,-141,-37,-171,17,-163,26,-180,46,-154,80,-63,48,-4,18,20,50,47,58,53,44,61,57,85,37,80,0,86,-8,106,-95,49,-213,-8,-131,47,49,63,40,-39,-69,-74,-37,-20,63,-12,58,-14,-12,25,-31,41,11,45,76,47,167,5,261,-37,277,-83,183,-172,35,-122,-79,138,-70,266,69,124,228,0,391,-29,594,-84,702,-78,627,-8,551,-13,509,13,372,120,352,125,622,127,691,223,362,126,386,-33,915,198,958,457,456,298,500,233,1027,469,1096,426,918,160,1067,141,1220,189,1245,164,1375,297,1378,503,1299,702,1550,929,1799,855,1752,547,1830,602,1928,832,1736,796,1735,933,1961,1385,1935,1562,2105,1485,2716,1449,2948,1305,2768,1205,2716,1346,2531,1450,2470,1653,3117,2111,3370,2176,2696,1947,2925,2305,3846,2658,2425,2184,-877,1981,-2261,2623,-1645,2908,-1876,2732,-2704,2953,-2484,3116,-2120,2954,-2442,3216,-2466,3499,-2192,3234,-2392,3361,-2497,3869,-2078,3772,-1858,3915,-2066,4438,-2285,2934,-2294,-280,-2066,-1762,-1992,-1412,-2298,-1535,-2399,-1789,-2223,-1419,-2244,-1334,-2092,-1476,-1777,-1396,-2014,-1571,-2199,-1574,-1843,-1167,-1910,-1446,-2007,-1818,-1506,-1331,-2526,-2048,-5535,-4573,-7148,-5828,-6422,-5327,-5840,-5488,-5992,-6144,-6014,-6164,-6109,-6234,-6271,-6388,-6288,-6156,-6517,-6249,-6794,-6602,-6822,-6418,-6788,-6245,-6490,-6560,-6394,-6794,-7920,-6937,-10397,-7140,-11428,-6972,-11019,-6610,-11141,-6665,-11913,-7046,-11979,-7235,-11599,-7015,-11854,-6912,-12161,-7441,-12136,-7761,-12861,-7292,-13390,-7254,-12345,-7809,-12490,-7463,-13983,-6969,-10489,-8465,-2382,-11054,1272,-12247,-270,-12060,-323,-12113,502,-12486,-697,-12251,-1086,-12141,-181,-13116,-670,-13509,-1173,-12592,-443,-12811,-449,-13698,-934,-12850,-747,-13083,-873,-15036,-1161,-11478,-1047,-2669,-1407,1006,-1658,-1146,-1195,-1297,-1421,-73,-1946,-977,-1590,-1499,-1577,-1010,-1862,-1256,-1389,-962,-1692,-509,-2613,-1317,-2087,-1359,-1997,-1034,-2891,-2024,-119,-84,5651,5723,8074,8306,7156,6870,6985,7106,7312,8403,7114,8096,7173,7848,7082,7827,6761,7189,6985,7368,7076,7835,6992,7297,7453,7260,7016,7755,6025,7429,8533,7352,14150,7628,17142,7077,16399,6947,15939,7475,16564,7069,16463,6882,16400,7602,17031,7233,16543,6517,15395,7018,15985,7104,16689,6869,15655,7622,16155,7198,17884,6022,14056,8856,5665,14484,1815,16782,3034,15786,3107,15664,2312,16517,2965,16443,3036,16120,2287,16584,2479,16720,2693,16073,2535,16159,2958,16609,3067,16086,2716,16579,3035,17752,3092,13704,2499,5265,2620,1452,2808,3024,2444,3275,2839,2267,3340,2857,2968,3232,3066,2867,3152,3072,2248,2961,2413,2807,3238,3237,2368,2699,2262,2392,3537,3339,827,823,-5020,-5359,-7095,-7857,-5973,-6274,-6208,-6279,-6934,-7181,-6893,-6647,-7146,-6687,-7026,-7328,-6451,-6924,-6763,-6535,-7109,-6639,-6926,-6559,-7188,-6799,-6727,-6955,-5786,-6554,-8543,-6796,-14465,-7190,-17356,-6641,-16372,-6529,-15941,-6898,-16526,-6434,-16219,-6520,-16222,-7449,-17077,-7097,-16665,-6476,-15675,-7026,-16498,-6848,-17147,-6271,-15894,-7069,-16266,-7032,-17817,-5991,-13796,-8594,-5421,-14349,-1649,-17288,-2847,-16525,-2974,-15945,-2324,-16482,-3022,-16593,-3097,-16451,-2420,-16780,-2649,-16641,-2836,-15900,-2660,-16214,-3050,-16827,-3111,-15993,-2741,-16151,-2994,-17537,-2933,-13812,-2314,-5216,-2475,-1125,-2648,-2801,-2290,-3285,-2796,-2243,-3415,-2642,-3109,-3000,-3271,-2839,-3408,-3161,-2497,-2876,-2603,-2570,-3351,-3173,-2416,-2832,-2235,-2408,-3405,-3186,-613,-768,5271,5201,7376,7644,6241,6176,6366,6275,6964,7124,6831,6508,6998,6566,6836,7230,6277,6777,6589,6376,6934,6536,6819,6494,7160,6749,6736,6900,5822,6476,8593,6747,14520,7204,17448,6637,16490,6483,16033,6906,16600,6511,16304,6568,16279,7438,17079,7072,16624,6463,15577,7028,16343,6877,16990,6331,15760,7121,16140,7023,17719,5944,13748,8575,5401,14336,1645,17210,2880,16419,3036,15896,2382,16483,3074,16584,3143,16425,2443,16782,2650,16695,2825,15978,2632,16272,3015,16880,3084,16096,2709,16289,2965,17641,2932,13887,2323,5330,2474,1286,2656,2954,2309,3410,2803,2373,3414,2795,3106,3151,3263,2952,3403,3241,2483,2969,2568,2681,3316,3245,2383,2837,2199,2390,3396,3165,641,706,-5230,-5323,-7307,-7790,-6136,-6317,-6268,-6419,-6884,-7278,-6766,-6666,-6976,-6731,-6853,-7406,-6308,-6958,-6636,-6553,-6978,-6703,-6829,-6647,-7156,-6883,-6737,-7017,-5814,-6581,-8575,-6833,-14490,-7270,-17411,-6699,-16466,-6539,-16016,-6931,-16571,-6504,-16257,-6551,-16202,-7408,-16983,-7021,-16545,-6410,-15512,-6976,-16305,-6803,-17017,-6243,-15820,-7037,-16197,-6923,-17802,-5820,-13840,-8455,-5475,-14227,-1724,-17099,-2923,-16314,-3008,-15801,-2362,-16392,-3088,-16506,-3163,-16356,-2503,-16700,-2717,-16605,-2855,-15904,-2710,-16226,-3108,-16870,-3089,-16101,-2747,-16257,-3087,-17584,-2975,-13868,-2324,-5343,-2548,-1275,-2673,-2917,-2213,-3363,-2694,-2311,-3251,-2744,-2867,-3129,-3034,-2939,-3190,-3234,-2346,-2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+
+use serde::Deserialize;
+
+#[derive(Deserialize)]
+struct DeriveStruct {
+    buffer: Vec<i16>,
+}
+
+fn main() {
+    let info: DeriveStruct = serde_json::from_str(JSON).unwrap();
+    println!("{}", info.buffer.len());
+}
diff --git a/src/tools/miri/bench-cargo-miri/serde2/Cargo.lock b/src/tools/miri/bench-cargo-miri/serde2/Cargo.lock
new file mode 100644
index 000000000000..487505761354
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/serde2/Cargo.lock
@@ -0,0 +1,89 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "cargo-miri-test"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "itoa"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "112c678d4050afce233f4f2852bb2eb519230b3cf12f33585275537d7e41578d"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c54b25569025b7fc9651de43004ae593a75ad88543b17178aa5e1b9c4f15f56f"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3f6f92acf49d1b98f7a81226834412ada05458b7364277387724a237f062695"
+
+[[package]]
+name = "serde"
+version = "1.0.137"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61ea8d54c77f8315140a05f4c7237403bf38b72704d031543aa1d16abbf517d1"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.137"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f26faba0c3959972377d3b2d306ee9f71faee9714294e41bb777f83f88578be"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b7ce2b32a1aed03c558dc61a5cd328f15aff2dbc17daad8fb8af04d2100e15c"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.96"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0748dd251e24453cb8717f0354206b91557e4ec8703673a4b30208f2abaf1ebf"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d22af068fba1eb5edcb4aea19d382b2a3deb4c8f9d475c589b6ada9e0fd493ee"
diff --git a/src/tools/miri/bench-cargo-miri/serde2/Cargo.toml b/src/tools/miri/bench-cargo-miri/serde2/Cargo.toml
new file mode 100644
index 000000000000..7cb863a7abf3
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/serde2/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "cargo-miri-test"
+version = "0.1.0"
+authors = ["Oliver Schneider <git-spam-no-reply9815368754983@oli-obk.de>"]
+edition = "2018"
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
diff --git a/src/tools/miri/bench-cargo-miri/serde2/src/main.rs b/src/tools/miri/bench-cargo-miri/serde2/src/main.rs
new file mode 100644
index 000000000000..c81b32c13fef
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/serde2/src/main.rs
@@ -0,0 +1,18 @@
+// Like serde1, but in two threads concurrently. And we don't print.
+static JSON: &str = r#"{"buffer":[-29,-42,-40,-37,-28,-5,-21,1,-24,-8,-20,4,-18,26,-24,44,-26,66,-30,86,-37,88,-41,72,-46,50,-31,28,23,14,64,16,51,26,32,34,39,42,48,35,58,0,72,-36,69,-59,58,-98,54,-124,36,-103,12,-110,5,-173,-19,-146,-59,-4,-42,51,1,-23,-6,-30,-6,45,46,47,70,6,55,19,60,38,62,42,47,61,46,40,42,-19,22,-34,6,-35,-50,-61,-141,-37,-171,17,-163,26,-180,46,-154,80,-63,48,-4,18,20,50,47,58,53,44,61,57,85,37,80,0,86,-8,106,-95,49,-213,-8,-131,47,49,63,40,-39,-69,-74,-37,-20,63,-12,58,-14,-12,25,-31,41,11,45,76,47,167,5,261,-37,277,-83,183,-172,35,-122,-79,138,-70,266,69,124,228,0,391,-29,594,-84,702,-78,627,-8,551,-13,509,13,372,120,352,125,622,127,691,223,362,126,386,-33,915,198,958,457,456,298,500,233,1027,469,1096,426,918,160,1067,141,1220,189,1245,164,1375,297,1378,503,1299,702,1550,929,1799,855,1752,547,1830,602,1928,832,1736,796,1735,933,1961,1385,1935,1562,2105,1485,2716,1449,2948,1305,2768,1205,2716,1346,2531,1450,2470,1653,3117,2111,3370,2176,2696,1947,2925,2305,3846,2658,2425,2184,-877,1981,-2261,2623,-1645,2908,-1876,2732,-2704,2953,-2484,3116,-2120,2954,-2442,3216,-2466,3499,-2192,3234,-2392,3361,-2497,3869,-2078,3772,-1858,3915,-2066,4438,-2285,2934,-2294,-280,-2066,-1762,-1992,-1412,-2298,-1535,-2399,-1789,-2223,-1419,-2244,-1334,-2092,-1476,-1777,-1396,-2014,-1571,-2199,-1574,-1843,-1167,-1910,-1446,-2007,-1818,-1506,-1331,-2526,-2048,-5535,-4573,-7148,-5828,-6422,-5327,-5840,-5488,-5992,-6144,-6014,-6164,-6109,-6234,-6271,-6388,-6288,-6156,-6517,-6249,-6794,-6602,-6822,-6418,-6788,-6245,-6490,-6560,-6394,-6794,-7920,-6937,-10397,-7140,-11428,-6972,-11019,-6610,-11141,-6665,-11913,-7046,-11979,-7235,-11599,-7015,-11854,-6912,-12161,-7441,-12136,-7761,-12861,-7292,-13390,-7254,-12345,-7809,-12490,-7463,-13983,-6969,-10489,-8465,-2382,-11054,1272,-12247,-270,-12060,-323,-12113,502,-12486,-697,-12251,-1086,-12141,-181,-13116,-670,-13509,-1173,-12592,-443,-12811,-449,-13698,-934,-12850,-747,-13083,-873,-15036,-1161,-11478,-1047,-2669,-1407,1006,-1658,-1146,-1195,-1297,-1421,-73,-1946,-977,-1590,-1499,-1577,-1010,-1862,-1256,-1389,-962,-1692,-509,-2613,-1317,-2087,-1359,-1997,-1034,-2891,-2024,-119,-84,5651,5723,8074,8306,7156,6870,6985,7106,7312,8403,7114,8096,7173,7848,7082,7827,6761,7189,6985,7368,7076,7835,6992,7297,7453,7260,7016,7755,6025,7429,8533,7352,14150,7628,17142,7077,16399,6947,15939,7475,16564,7069,16463,6882,16400,7602,17031,7233,16543,6517,15395,7018,15985,7104,16689,6869,15655,7622,16155,7198,17884,6022,14056,8856,5665,14484,1815,16782,3034,15786,3107,15664,2312,16517,2965,16443,3036,16120,2287,16584,2479,16720,2693,16073,2535,16159,2958,16609,3067,16086,2716,16579,3035,17752,3092,13704,2499,5265,2620,1452,2808,3024,2444,3275,2839,2267,3340,2857,2968,3232,3066,2867,3152,3072,2248,2961,2413,2807,3238,3237,2368,2699,2262,2392,3537,3339,827,823,-5020,-5359,-7095,-7857,-5973,-6274,-6208,-6279,-6934,-7181,-6893,-6647,-7146,-6687,-7026,-7328,-6451,-6924,-6763,-6535,-7109,-6639,-6926,-6559,-7188,-6799,-6727,-6955,-5786,-6554,-8543,-6796,-14465,-7190,-17356,-6641,-16372,-6529,-15941,-6898,-16526,-6434,-16219,-6520,-16222,-7449,-17077,-7097,-16665,-6476,-15675,-7026,-16498,-6848,-17147,-6271,-15894,-7069,-16266,-7032,-17817,-5991,-13796,-8594,-5421,-14349,-1649,-17288,-2847,-16525,-2974,-15945,-2324,-16482,-3022,-16593,-3097,-16451,-2420,-16780,-2649,-16641,-2836,-15900,-2660,-16214,-3050,-16827,-3111,-15993,-2741,-16151,-2994,-17537,-2933,-13812,-2314,-5216,-2475,-1125,-2648,-2801,-2290,-3285,-2796,-2243,-3415,-2642,-3109,-3000,-3271,-2839,-3408,-3161,-2497,-2876,-2603,-2570,-3351,-3173,-2416,-2832,-2235,-2408,-3405,-3186,-613,-768,5271,5201,7376,7644,6241,6176,6366,6275,6964,7124,6831,6508,6998,6566,6836,7230,6277,6777,6589,6376,6934,6536,6819,6494,7160,6749,6736,6900,5822,6476,8593,6747,14520,7204,17448,6637,16490,6483,16033,6906,16600,6511,16304,6568,16279,7438,17079,7072,16624,6463,15577,7028,16343,6877,16990,6331,15760,7121,16140,7023,17719,5944,13748,8575,5401,14336,1645,17210,2880,16419,3036,15896,2382,16483,3074,16584,3143,16425,2443,16782,2650,16695,2825,15978,2632,16272,3015,16880,3084,16096,2709,16289,2965,17641,2932,13887,2323,5330,2474,1286,2656,2954,2309,3410,2803,2373,3414,2795,3106,3151,3263,2952,3403,3241,2483,2969,2568,2681,3316,3245,2383,2837,2199,2390,3396,3165,641,706,-5230,-5323,-7307,-7790,-6136,-6317,-6268,-6419,-6884,-7278,-6766,-6666,-6976,-6731,-6853,-7406,-6308,-6958,-6636,-6553,-6978,-6703,-6829,-6647,-7156,-6883,-6737,-7017,-5814,-6581,-8575,-6833,-14490,-7270,-17411,-6699,-16466,-6539,-16016,-6931,-16571,-6504,-16257,-6551,-16202,-7408,-16983,-7021,-16545,-6410,-15512,-6976,-16305,-6803,-17017,-6243,-15820,-7037,-16197,-6923,-17802,-5820,-13840,-8455,-5475,-14227,-1724,-17099,-2923,-16314,-3008,-15801,-2362,-16392,-3088,-16506,-3163,-16356,-2503,-16700,-2717,-16605,-2855,-15904,-2710,-16226,-3108,-16870,-3089,-16101,-2747,-16257,-3087,-17584,-2975,-13868,-2324,-5343,-2548,-1275,-2673,-2917,-2213,-3363,-2694,-2311,-3251,-2744,-2867,-3129,-3034,-2939,-3190,-3234,-2346,-2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+
+use serde::Deserialize;
+use std::thread;
+
+#[derive(Deserialize)]
+struct DeriveStruct {
+    buffer: Vec<i16>,
+}
+
+fn main() {
+    let t = thread::spawn(|| {
+        let _info: DeriveStruct = serde_json::from_str(JSON).unwrap();
+    });
+    let _info: DeriveStruct = serde_json::from_str(JSON).unwrap();
+    t.join().unwrap();
+}
diff --git a/src/tools/miri/bench-cargo-miri/slice-get-unchecked/Cargo.lock b/src/tools/miri/bench-cargo-miri/slice-get-unchecked/Cargo.lock
new file mode 100644
index 000000000000..a375afaed309
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/slice-get-unchecked/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "slice-get-unchecked"
+version = "0.1.0"
diff --git a/src/tools/miri/bench-cargo-miri/slice-get-unchecked/Cargo.toml b/src/tools/miri/bench-cargo-miri/slice-get-unchecked/Cargo.toml
new file mode 100644
index 000000000000..1ac2276866ff
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/slice-get-unchecked/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "slice-get-unchecked"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/tools/miri/bench-cargo-miri/slice-get-unchecked/src/main.rs b/src/tools/miri/bench-cargo-miri/slice-get-unchecked/src/main.rs
new file mode 100644
index 000000000000..a72083bd9de3
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/slice-get-unchecked/src/main.rs
@@ -0,0 +1,12 @@
+//! This is a stripped-down version of the code pattern that causes runtime blowup when printing
+//! backtraces in a failed test under cargo miri test with -Zmiri-disable-isolation.
+//! See https://github.com/rust-lang/miri/issues/2273
+
+fn main() {
+    let x = vec![0u8; 4096];
+    let mut i = 0;
+    while i < x.len() {
+        let _element = unsafe { *x.get_unchecked(i) };
+        i += 1;
+    }
+}
diff --git a/src/tools/miri/bench-cargo-miri/unicode/Cargo.lock b/src/tools/miri/bench-cargo-miri/unicode/Cargo.lock
new file mode 100644
index 000000000000..80d013b7d6d8
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/unicode/Cargo.lock
@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "unicode"
+version = "0.1.0"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "957e51f3646910546462e67d5f7599b9e4fb8acdd304b087a6494730f9eebf04"
diff --git a/src/tools/miri/bench-cargo-miri/unicode/Cargo.toml b/src/tools/miri/bench-cargo-miri/unicode/Cargo.toml
new file mode 100644
index 000000000000..7e8708b03f19
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/unicode/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "unicode"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+unicode-xid = "0.2.3"
diff --git a/src/tools/miri/bench-cargo-miri/unicode/src/main.rs b/src/tools/miri/bench-cargo-miri/unicode/src/main.rs
new file mode 100644
index 000000000000..3cf25ba9cf6c
--- /dev/null
+++ b/src/tools/miri/bench-cargo-miri/unicode/src/main.rs
@@ -0,0 +1,20 @@
+//! Extracted from the unicode-xid exhaustive test all_valid_chars_do_not_panic_for_is_xid_continue
+
+use unicode_xid::UnicodeXID;
+
+/// A `char` in Rust is a Unicode Scalar Value
+///
+/// See: http://www.unicode.org/glossary/#unicode_scalar_value
+fn all_valid_chars() -> impl Iterator<Item = char> {
+    (0u32..=0xD7FF).chain(0xE000u32..=0x10FFFF).map(|u| {
+        core::convert::TryFrom::try_from(u)
+            .expect("The selected range should be infallible if the docs match impl")
+    })
+}
+
+fn main() {
+    // Take only the first few chars because we don't want to wait all day
+    for c in all_valid_chars().take(1_500) {
+        let _ = UnicodeXID::is_xid_continue(c);
+    }
+}
diff --git a/src/tools/miri/build.rs b/src/tools/miri/build.rs
new file mode 100644
index 000000000000..37c626baab58
--- /dev/null
+++ b/src/tools/miri/build.rs
@@ -0,0 +1,8 @@
+fn main() {
+    // Don't rebuild miri when nothing changed.
+    println!("cargo:rerun-if-changed=build.rs");
+    // Re-export the TARGET environment variable so it can
+    // be accessed by miri.
+    let target = std::env::var("TARGET").unwrap();
+    println!("cargo:rustc-env=TARGET={}", target);
+}
diff --git a/src/tools/miri/cargo-miri/Cargo.lock b/src/tools/miri/cargo-miri/Cargo.lock
new file mode 100644
index 000000000000..95c2bda505c5
--- /dev/null
+++ b/src/tools/miri/cargo-miri/Cargo.lock
@@ -0,0 +1,554 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "anyhow"
+version = "1.0.51"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b26702f315f53b6071259e15dd9d64528213b44d61de1ec926eca7715d62203"
+
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "camino"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "869119e97797867fd90f5e22af7d0bd274bd4635ebb9eb68c04f3f513ae6c412"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo-miri"
+version = "0.1.0"
+dependencies = [
+ "cargo_metadata",
+ "directories",
+ "rustc-workspace-hack",
+ "rustc_version",
+ "serde",
+ "serde_json",
+ "vergen",
+]
+
+[[package]]
+name = "cargo-platform"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbdb825da8a5df079a43676dbe042702f1707b1109f713a01420fbb4cc71fa27"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo_metadata"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3abb7553d5b9b8421c6de7cb02606ff15e0c6eea7d8eadd75ef013fd636bec36"
+dependencies = [
+ "camino",
+ "cargo-platform",
+ "semver",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "cc"
+version = "1.0.72"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22a9137b95ea06864e018375b72adfb7db6e6f68cfc8df5a04d00288050485ee"
+dependencies = [
+ "jobserver",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "chrono"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "time",
+ "winapi",
+]
+
+[[package]]
+name = "directories"
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diff --git a/src/tools/miri/cargo-miri/Cargo.toml b/src/tools/miri/cargo-miri/Cargo.toml
new file mode 100644
index 000000000000..9ac170c5b537
--- /dev/null
+++ b/src/tools/miri/cargo-miri/Cargo.toml
@@ -0,0 +1,32 @@
+[package]
+authors = ["Miri Team"]
+description = "An experimental interpreter for Rust MIR (cargo wrapper)."
+license = "MIT OR Apache-2.0"
+name = "cargo-miri"
+repository = "https://github.com/rust-lang/miri"
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "cargo-miri"
+path = "src/main.rs"
+test = false # we have no unit tests
+doctest = false # and no doc tests
+
+[dependencies]
+directories = "3"
+rustc_version = "0.4"
+serde_json = "1.0.40"
+cargo_metadata = "0.15.0"
+
+# A noop dependency that changes in the Rust repository, it's a bit of a hack.
+# See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`
+# for more information.
+rustc-workspace-hack = "1.0.0"
+
+# Enable some feature flags that dev-dependencies need but dependencies
+# do not.  This makes `./miri install` after `./miri build` faster.
+serde = { version = "*", features = ["derive"] }
+
+[build-dependencies]
+vergen = { version = "5", default_features = false, features = ["git"] }
diff --git a/src/tools/miri/cargo-miri/build.rs b/src/tools/miri/cargo-miri/build.rs
new file mode 100644
index 000000000000..ebd8e7003d5f
--- /dev/null
+++ b/src/tools/miri/cargo-miri/build.rs
@@ -0,0 +1,11 @@
+use vergen::vergen;
+
+fn main() {
+    // Don't rebuild miri when nothing changed.
+    println!("cargo:rerun-if-changed=build.rs");
+    // vergen
+    let mut gen_config = vergen::Config::default();
+    *gen_config.git_mut().sha_kind_mut() = vergen::ShaKind::Short;
+    *gen_config.git_mut().commit_timestamp_kind_mut() = vergen::TimestampKind::DateOnly;
+    vergen(gen_config).ok(); // Ignore failure (in case we are built outside a git repo)
+}
diff --git a/src/tools/miri/cargo-miri/miri b/src/tools/miri/cargo-miri/miri
new file mode 100755
index 000000000000..cf3ad06788ab
--- /dev/null
+++ b/src/tools/miri/cargo-miri/miri
@@ -0,0 +1,4 @@
+#!/bin/sh
+# RA invokes `./miri cargo ...` for each workspace, so we need to forward that to the main `miri`
+# script. See <https://github.com/rust-analyzer/rust-analyzer/issues/10793>.
+exec "$(dirname "$0")"/../miri "$@"
diff --git a/src/tools/miri/cargo-miri/src/arg.rs b/src/tools/miri/cargo-miri/src/arg.rs
new file mode 100644
index 000000000000..e8bac4625f71
--- /dev/null
+++ b/src/tools/miri/cargo-miri/src/arg.rs
@@ -0,0 +1,134 @@
+//! Utilities for dealing with argument flags
+
+use std::borrow::Cow;
+use std::env;
+
+/// Determines whether a `--flag` is present.
+pub fn has_arg_flag(name: &str) -> bool {
+    num_arg_flag(name) > 0
+}
+
+/// Determines how many times a `--flag` is present.
+pub fn num_arg_flag(name: &str) -> usize {
+    env::args().take_while(|val| val != "--").filter(|val| val == name).count()
+}
+
+/// Yields all values of command line flag `name` as `Ok(arg)`, and all other arguments except
+/// the flag as `Err(arg)`. (The flag `name` itself is not yielded at all, only its values are.)
+pub struct ArgSplitFlagValue<'a, I> {
+    args: Option<I>,
+    name: &'a str,
+}
+
+impl<'a, I: Iterator> ArgSplitFlagValue<'a, I> {
+    fn new(args: I, name: &'a str) -> Self {
+        Self { args: Some(args), name }
+    }
+}
+
+impl<'s, I: Iterator<Item = Cow<'s, str>>> Iterator for ArgSplitFlagValue<'_, I> {
+    // If the original iterator was all `Owned`, then we will only ever yield `Owned`
+    // (so `into_owned()` is cheap).
+    type Item = Result<Cow<'s, str>, Cow<'s, str>>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let Some(args) = self.args.as_mut() else {
+            // We already canceled this iterator.
+            return None;
+        };
+        let arg = args.next()?;
+        if arg == "--" {
+            // Stop searching at `--`.
+            self.args = None;
+            return None;
+        }
+        // These branches cannot be merged if we want to avoid the allocation in the `Borrowed` branch.
+        match &arg {
+            Cow::Borrowed(arg) =>
+                if let Some(suffix) = arg.strip_prefix(self.name) {
+                    // Strip leading `name`.
+                    if suffix.is_empty() {
+                        // This argument is exactly `name`; the next one is the value.
+                        return args.next().map(Ok);
+                    } else if let Some(suffix) = suffix.strip_prefix('=') {
+                        // This argument is `name=value`; get the value.
+                        return Some(Ok(Cow::Borrowed(suffix)));
+                    }
+                },
+            Cow::Owned(arg) =>
+                if let Some(suffix) = arg.strip_prefix(self.name) {
+                    // Strip leading `name`.
+                    if suffix.is_empty() {
+                        // This argument is exactly `name`; the next one is the value.
+                        return args.next().map(Ok);
+                    } else if let Some(suffix) = suffix.strip_prefix('=') {
+                        // This argument is `name=value`; get the value. We need to do an allocation
+                        // here as a `String` cannot be subsliced (what would the lifetime be?).
+                        return Some(Ok(Cow::Owned(suffix.to_owned())));
+                    }
+                },
+        }
+        Some(Err(arg))
+    }
+}
+
+impl<'a, I: Iterator<Item = String> + 'a> ArgSplitFlagValue<'a, I> {
+    pub fn from_string_iter(
+        args: I,
+        name: &'a str,
+    ) -> impl Iterator<Item = Result<String, String>> + 'a {
+        ArgSplitFlagValue::new(args.map(Cow::Owned), name).map(|x| {
+            match x {
+                Ok(Cow::Owned(s)) => Ok(s),
+                Err(Cow::Owned(s)) => Err(s),
+                _ => panic!("iterator converted owned to borrowed"),
+            }
+        })
+    }
+}
+
+impl<'x: 'a, 'a, I: Iterator<Item = &'x str> + 'a> ArgSplitFlagValue<'a, I> {
+    pub fn from_str_iter(
+        args: I,
+        name: &'a str,
+    ) -> impl Iterator<Item = Result<&'x str, &'x str>> + 'a {
+        ArgSplitFlagValue::new(args.map(Cow::Borrowed), name).map(|x| {
+            match x {
+                Ok(Cow::Borrowed(s)) => Ok(s),
+                Err(Cow::Borrowed(s)) => Err(s),
+                _ => panic!("iterator converted borrowed to owned"),
+            }
+        })
+    }
+}
+
+/// Yields all values of command line flag `name`.
+pub struct ArgFlagValueIter;
+
+impl ArgFlagValueIter {
+    pub fn from_string_iter<'a, I: Iterator<Item = String> + 'a>(
+        args: I,
+        name: &'a str,
+    ) -> impl Iterator<Item = String> + 'a {
+        ArgSplitFlagValue::from_string_iter(args, name).filter_map(Result::ok)
+    }
+}
+
+impl ArgFlagValueIter {
+    pub fn from_str_iter<'x: 'a, 'a, I: Iterator<Item = &'x str> + 'a>(
+        args: I,
+        name: &'a str,
+    ) -> impl Iterator<Item = &'x str> + 'a {
+        ArgSplitFlagValue::from_str_iter(args, name).filter_map(Result::ok)
+    }
+}
+
+/// Gets the values of a `--flag`.
+pub fn get_arg_flag_values(name: &str) -> impl Iterator<Item = String> + '_ {
+    ArgFlagValueIter::from_string_iter(env::args(), name)
+}
+
+/// Gets the value of a `--flag`.
+pub fn get_arg_flag_value(name: &str) -> Option<String> {
+    get_arg_flag_values(name).next()
+}
diff --git a/src/tools/miri/cargo-miri/src/main.rs b/src/tools/miri/cargo-miri/src/main.rs
new file mode 100644
index 000000000000..da891ef07729
--- /dev/null
+++ b/src/tools/miri/cargo-miri/src/main.rs
@@ -0,0 +1,98 @@
+#![cfg_attr(bootstrap, feature(let_else))]
+#![allow(clippy::useless_format, clippy::derive_partial_eq_without_eq, rustc::internal)]
+
+#[macro_use]
+mod util;
+
+mod arg;
+mod phases;
+mod setup;
+mod version;
+
+use std::{env, iter};
+
+use crate::phases::*;
+
+fn main() {
+    // Rustc does not support non-UTF-8 arguments so we make no attempt either.
+    // (We do support non-UTF-8 environment variables though.)
+    let mut args = std::env::args();
+    // Skip binary name.
+    args.next().unwrap();
+
+    // Dispatch to `cargo-miri` phase. Here is a rough idea of "who calls who".
+    //
+    // Initially, we are invoked as `cargo-miri miri run/test`. We first run the setup phase:
+    // - We call `xargo`, and set `RUSTC` back to us, together with `MIRI_CALLED_FROM_XARGO`,
+    //   so that xargo's rustc invocations end up in `phase_rustc` with `RustcPhase::Setup`.
+    //   There we then call the Miri driver with `MIRI_BE_RUSTC` to perform the actual build.
+    //
+    // Then we call `cargo run/test`, exactly forwarding all user flags, plus some configuration so
+    // that we control every binary invoked by cargo:
+    // - We set RUSTC_WRAPPER to ourselves, so for (almost) all rustc invocations, we end up in
+    //   `phase_rustc` with `RustcPhase::Build`. This will in turn either determine that a
+    //   dependency needs to be built (for which it invokes the Miri driver with `MIRI_BE_RUSTC`),
+    //   or determine that this is a binary Miri should run, in which case we generate a JSON file
+    //   with all the information needed to build and run this crate.
+    //   (We don't run it yet since cargo thinks this is a build step, not a run step -- running the
+    //   binary here would lead to a bad user experience.)
+    // - We set RUSTC to the Miri driver and also set `MIRI_BE_RUSTC`, so that gets called by build
+    //   scripts (and cargo uses it for the version query).
+    // - We set `target.*.runner` to `cargo-miri runner`, which ends up calling `phase_runner` for
+    //   `RunnerPhase::Cargo`. This parses the JSON file written in `phase_rustc` and then invokes
+    //   the actual Miri driver for interpretation.
+    // - We set RUSTDOC to ourselves, which ends up in `phase_rustdoc`. There we call regular
+    //   rustdoc with some extra flags, and we set `MIRI_CALLED_FROM_RUSTDOC` to recognize this
+    //   phase in our recursive invocations:
+    //   - We set the `--test-builder` flag of rustdoc to ourselves, which ends up in `phase_rustc`
+    //     with `RustcPhase::Rustdoc`. There we perform a check-build (needed to get the expected
+    //     build failures for `compile_fail` doctests) and then store a JSON file with the
+    //     information needed to run this test.
+    //   - We also set `--runtool` to ourselves, which ends up in `phase_runner` with
+    //     `RunnerPhase::Rustdoc`. There we parse the JSON file written in `phase_rustc` and invoke
+    //     the Miri driver for interpretation.
+
+    // Dispatch running as part of sysroot compilation.
+    if env::var_os("MIRI_CALLED_FROM_XARGO").is_some() {
+        phase_rustc(args, RustcPhase::Setup);
+        return;
+    }
+
+    // The way rustdoc invokes rustc is indistuingishable from the way cargo invokes rustdoc by the
+    // arguments alone. `phase_cargo_rustdoc` sets this environment variable to let us disambiguate.
+    if env::var_os("MIRI_CALLED_FROM_RUSTDOC").is_some() {
+        // ...however, we then also see this variable when rustdoc invokes us as the testrunner!
+        // The runner is invoked as `$runtool ($runtool-arg)* output_file`;
+        // since we don't specify any runtool-args, and rustdoc supplies multiple arguments to
+        // the test-builder unconditionally, we can just check the number of remaining arguments:
+        if args.len() == 1 {
+            phase_runner(args, RunnerPhase::Rustdoc);
+        } else {
+            phase_rustc(args, RustcPhase::Rustdoc);
+        }
+
+        return;
+    }
+
+    let Some(first) = args.next() else {
+        show_error!(
+            "`cargo-miri` called without first argument; please only invoke this binary through `cargo miri`"
+        )
+    };
+    match first.as_str() {
+        "miri" => phase_cargo_miri(args),
+        "runner" => phase_runner(args, RunnerPhase::Cargo),
+        arg if arg == env::var("RUSTC").unwrap() => {
+            // If the first arg is equal to the RUSTC env ariable (which should be set at this
+            // point), then we need to behave as rustc. This is the somewhat counter-intuitive
+            // behavior of having both RUSTC and RUSTC_WRAPPER set
+            // (see https://github.com/rust-lang/cargo/issues/10886).
+            phase_rustc(args, RustcPhase::Build)
+        }
+        _ => {
+            // Everything else must be rustdoc. But we need to get `first` "back onto the iterator",
+            // it is some part of the rustdoc invocation.
+            phase_rustdoc(iter::once(first).chain(args));
+        }
+    }
+}
diff --git a/src/tools/miri/cargo-miri/src/phases.rs b/src/tools/miri/cargo-miri/src/phases.rs
new file mode 100644
index 000000000000..93eb3cb17465
--- /dev/null
+++ b/src/tools/miri/cargo-miri/src/phases.rs
@@ -0,0 +1,601 @@
+//! Implements the various phases of `cargo miri run/test`.
+
+use std::env;
+use std::fmt::Write as _;
+use std::fs::{self, File};
+use std::io::BufReader;
+use std::path::PathBuf;
+use std::process::Command;
+
+use crate::{setup::*, util::*};
+
+const CARGO_MIRI_HELP: &str = r#"Runs binary crates and tests in Miri
+
+Usage:
+    cargo miri [subcommand] [<cargo options>...] [--] [<program/test suite options>...]
+
+Subcommands:
+    run, r                   Run binaries
+    test, t                  Run tests
+    nextest                  Run tests with nextest (requires cargo-nextest installed)
+    setup                    Only perform automatic setup, but without asking questions (for getting a proper libstd)
+
+The cargo options are exactly the same as for `cargo run` and `cargo test`, respectively.
+
+Examples:
+    cargo miri run
+    cargo miri test -- test-suite-filter
+
+    cargo miri setup --print sysroot
+        This will print the path to the generated sysroot (and nothing else) on stdout.
+        stderr will still contain progress information about how the build is doing.
+
+"#;
+
+fn show_help() {
+    println!("{}", CARGO_MIRI_HELP);
+}
+
+fn show_version() {
+    let mut version = format!("miri {}", env!("CARGO_PKG_VERSION"));
+    // Only use `option_env` on vergen variables to ensure the build succeeds
+    // when vergen failed to find the git info.
+    if let Some(sha) = option_env!("VERGEN_GIT_SHA_SHORT") {
+        // This `unwrap` can never fail because if VERGEN_GIT_SHA_SHORT exists, then so does
+        // VERGEN_GIT_COMMIT_DATE.
+        #[allow(clippy::option_env_unwrap)]
+        write!(&mut version, " ({} {})", sha, option_env!("VERGEN_GIT_COMMIT_DATE").unwrap())
+            .unwrap();
+    }
+    println!("{}", version);
+}
+
+fn forward_patched_extern_arg(args: &mut impl Iterator<Item = String>, cmd: &mut Command) {
+    cmd.arg("--extern"); // always forward flag, but adjust filename:
+    let path = args.next().expect("`--extern` should be followed by a filename");
+    if let Some(lib) = path.strip_suffix(".rlib") {
+        // If this is an rlib, make it an rmeta.
+        cmd.arg(format!("{}.rmeta", lib));
+    } else {
+        // Some other extern file (e.g. a `.so`). Forward unchanged.
+        cmd.arg(path);
+    }
+}
+
+pub fn phase_cargo_miri(mut args: impl Iterator<Item = String>) {
+    // Check for version and help flags even when invoked as `cargo-miri`.
+    if has_arg_flag("--help") || has_arg_flag("-h") {
+        show_help();
+        return;
+    }
+    if has_arg_flag("--version") || has_arg_flag("-V") {
+        show_version();
+        return;
+    }
+
+    // Require a subcommand before any flags.
+    // We cannot know which of those flags take arguments and which do not,
+    // so we cannot detect subcommands later.
+    let Some(subcommand) = args.next() else {
+        show_error!("`cargo miri` needs to be called with a subcommand (`run`, `test`)");
+    };
+    let subcommand = match &*subcommand {
+        "setup" => MiriCommand::Setup,
+        "test" | "t" | "run" | "r" | "nextest" => MiriCommand::Forward(subcommand),
+        _ =>
+            show_error!(
+                "`cargo miri` supports the following subcommands: `run`, `test`, `nextest`, and `setup`."
+            ),
+    };
+    let verbose = num_arg_flag("-v");
+
+    // Determine the involved architectures.
+    let host = version_info().host;
+    let target = get_arg_flag_value("--target");
+    let target = target.as_ref().unwrap_or(&host);
+
+    // We always setup.
+    setup(&subcommand, &host, target);
+
+    // Invoke actual cargo for the job, but with different flags.
+    // We re-use `cargo test` and `cargo run`, which makes target and binary handling very easy but
+    // requires some extra work to make the build check-only (see all the `--emit` hacks below).
+    // <https://github.com/rust-lang/miri/pull/1540#issuecomment-693553191> describes an alternative
+    // approach that uses `cargo check`, making that part easier but target and binary handling
+    // harder.
+    let cargo_miri_path = std::env::current_exe()
+        .expect("current executable path invalid")
+        .into_os_string()
+        .into_string()
+        .expect("current executable path is not valid UTF-8");
+    let cargo_cmd = match subcommand {
+        MiriCommand::Forward(s) => s,
+        MiriCommand::Setup => return, // `cargo miri setup` stops here.
+    };
+    let metadata = get_cargo_metadata();
+    let mut cmd = cargo();
+    cmd.arg(cargo_cmd);
+
+    // Forward all arguments before `--` other than `--target-dir` and its value to Cargo.
+    // (We want to *change* the target-dir value, so we must not forward it.)
+    let mut target_dir = None;
+    for arg in ArgSplitFlagValue::from_string_iter(&mut args, "--target-dir") {
+        match arg {
+            Ok(value) => {
+                if target_dir.is_some() {
+                    show_error!("`--target-dir` is provided more than once");
+                }
+                target_dir = Some(value.into());
+            }
+            Err(arg) => {
+                cmd.arg(arg);
+            }
+        }
+    }
+    // Detect the target directory if it's not specified via `--target-dir`.
+    // (`cargo metadata` does not support `--target-dir`, that's why we have to handle this ourselves.)
+    let target_dir = target_dir.get_or_insert_with(|| metadata.target_directory.clone());
+    // Set `--target-dir` to `miri` inside the original target directory.
+    target_dir.push("miri");
+    cmd.arg("--target-dir").arg(target_dir);
+
+    // Make sure the build target is explicitly set.
+    // This is needed to make the `target.runner` settings do something,
+    // and it later helps us detect which crates are proc-macro/build-script
+    // (host crates) and which crates are needed for the program itself.
+    if get_arg_flag_value("--target").is_none() {
+        // No target given. Explicitly pick the host.
+        cmd.arg("--target");
+        cmd.arg(&host);
+    }
+
+    // Set ourselves as runner for al binaries invoked by cargo.
+    // We use `all()` since `true` is not a thing in cfg-lang, but the empty conjunction is. :)
+    let cargo_miri_path_for_toml = escape_for_toml(&cargo_miri_path);
+    cmd.arg("--config")
+        .arg(format!("target.'cfg(all())'.runner=[{cargo_miri_path_for_toml}, 'runner']"));
+
+    // Forward all further arguments after `--` to cargo.
+    cmd.arg("--").args(args);
+
+    // Set `RUSTC_WRAPPER` to ourselves.  Cargo will prepend that binary to its usual invocation,
+    // i.e., the first argument is `rustc` -- which is what we use in `main` to distinguish
+    // the two codepaths. (That extra argument is why we prefer this over setting `RUSTC`.)
+    if env::var_os("RUSTC_WRAPPER").is_some() {
+        println!(
+            "WARNING: Ignoring `RUSTC_WRAPPER` environment variable, Miri does not support wrapping."
+        );
+    }
+    cmd.env("RUSTC_WRAPPER", &cargo_miri_path);
+    // We are going to invoke `MIRI` for everything, not `RUSTC`.
+    if env::var_os("RUSTC").is_some() && env::var_os("MIRI").is_none() {
+        println!(
+            "WARNING: Ignoring `RUSTC` environment variable; set `MIRI` if you want to control the binary used as the driver."
+        );
+    }
+    // Build scripts (and also cargo: https://github.com/rust-lang/cargo/issues/10885) will invoke
+    // `rustc` even when `RUSTC_WRAPPER` is set. To make sure everything is coherent, we want that
+    // to be the Miri driver, but acting as rustc, on the target level. (Target, rather than host,
+    // is needed for cross-interpretation situations.) This is not a perfect emulation of real rustc
+    // (it might be unable to produce binaries since the sysroot is check-only), but it's as close
+    // as we can get, and it's good enough for autocfg.
+    //
+    // In `main`, we need the value of `RUSTC` to distinguish RUSTC_WRAPPER invocations from rustdoc
+    // or TARGET_RUNNER invocations, so we canonicalize it here to make it exceedingly unlikely that
+    // there would be a collision with other invocations of cargo-miri (as rustdoc or as runner). We
+    // explicitly do this even if RUSTC_STAGE is set, since for these builds we do *not* want the
+    // bootstrap `rustc` thing in our way! Instead, we have MIRI_HOST_SYSROOT to use for host
+    // builds.
+    cmd.env("RUSTC", &fs::canonicalize(find_miri()).unwrap());
+    cmd.env("MIRI_BE_RUSTC", "target"); // we better remember to *unset* this in the other phases!
+
+    // Set rustdoc to us as well, so we can run doctests.
+    cmd.env("RUSTDOC", &cargo_miri_path);
+
+    cmd.env("MIRI_LOCAL_CRATES", local_crates(&metadata));
+    if verbose > 0 {
+        cmd.env("MIRI_VERBOSE", verbose.to_string()); // This makes the other phases verbose.
+    }
+
+    // Run cargo.
+    debug_cmd("[cargo-miri miri]", verbose, &cmd);
+    exec(cmd)
+}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum RustcPhase {
+    /// `rustc` called via `xargo` for sysroot build.
+    Setup,
+    /// `rustc` called by `cargo` for regular build.
+    Build,
+    /// `rustc` called by `rustdoc` for doctest.
+    Rustdoc,
+}
+
+pub fn phase_rustc(mut args: impl Iterator<Item = String>, phase: RustcPhase) {
+    /// Determines if we are being invoked (as rustc) to build a crate for
+    /// the "target" architecture, in contrast to the "host" architecture.
+    /// Host crates are for build scripts and proc macros and still need to
+    /// be built like normal; target crates need to be built for or interpreted
+    /// by Miri.
+    ///
+    /// Currently, we detect this by checking for "--target=", which is
+    /// never set for host crates. This matches what rustc bootstrap does,
+    /// which hopefully makes it "reliable enough". This relies on us always
+    /// invoking cargo itself with `--target`, which `in_cargo_miri` ensures.
+    fn is_target_crate() -> bool {
+        get_arg_flag_value("--target").is_some()
+    }
+
+    /// Returns whether or not Cargo invoked the wrapper (this binary) to compile
+    /// the final, binary crate (either a test for 'cargo test', or a binary for 'cargo run')
+    /// Cargo does not give us this information directly, so we need to check
+    /// various command-line flags.
+    fn is_runnable_crate() -> bool {
+        let is_bin = get_arg_flag_value("--crate-type").as_deref().unwrap_or("bin") == "bin";
+        let is_test = has_arg_flag("--test");
+        is_bin || is_test
+    }
+
+    fn out_filename(prefix: &str, suffix: &str) -> PathBuf {
+        if let Some(out_dir) = get_arg_flag_value("--out-dir") {
+            let mut path = PathBuf::from(out_dir);
+            path.push(format!(
+                "{}{}{}{}",
+                prefix,
+                get_arg_flag_value("--crate-name").unwrap(),
+                // This is technically a `-C` flag but the prefix seems unique enough...
+                // (and cargo passes this before the filename so it should be unique)
+                get_arg_flag_value("extra-filename").unwrap_or_default(),
+                suffix,
+            ));
+            path
+        } else {
+            let out_file = get_arg_flag_value("-o").unwrap();
+            PathBuf::from(out_file)
+        }
+    }
+
+    // phase_cargo_miri set `MIRI_BE_RUSTC` for when build scripts directly invoke the driver;
+    // however, if we get called back by cargo here, we'll carefully compute the right flags
+    // ourselves, so we first un-do what the earlier phase did.
+    env::remove_var("MIRI_BE_RUSTC");
+
+    let verbose = std::env::var("MIRI_VERBOSE")
+        .map_or(0, |verbose| verbose.parse().expect("verbosity flag must be an integer"));
+    let target_crate = is_target_crate();
+    // Determine whether this is cargo/xargo invoking rustc to get some infos.
+    let info_query = get_arg_flag_value("--print").is_some() || has_arg_flag("-vV");
+
+    let store_json = |info: CrateRunInfo| {
+        // Create a stub .d file to stop Cargo from "rebuilding" the crate:
+        // https://github.com/rust-lang/miri/issues/1724#issuecomment-787115693
+        // As we store a JSON file instead of building the crate here, an empty file is fine.
+        let dep_info_name = out_filename("", ".d");
+        if verbose > 0 {
+            eprintln!("[cargo-miri rustc] writing stub dep-info to `{}`", dep_info_name.display());
+        }
+        File::create(dep_info_name).expect("failed to create fake .d file");
+
+        let filename = out_filename("", "");
+        if verbose > 0 {
+            eprintln!("[cargo-miri rustc] writing run info to `{}`", filename.display());
+        }
+        info.store(&filename);
+        // For Windows, do the same thing again with `.exe` appended to the filename.
+        // (Need to do this here as cargo moves that "binary" to a different place before running it.)
+        info.store(&out_filename("", ".exe"));
+    };
+
+    let runnable_crate = !info_query && is_runnable_crate();
+
+    if runnable_crate && target_crate {
+        assert!(
+            phase != RustcPhase::Setup,
+            "there should be no interpretation during sysroot build"
+        );
+        let inside_rustdoc = phase == RustcPhase::Rustdoc;
+        // This is the binary or test crate that we want to interpret under Miri.
+        // But we cannot run it here, as cargo invoked us as a compiler -- our stdin and stdout are not
+        // like we want them.
+        // Instead of compiling, we write JSON into the output file with all the relevant command-line flags
+        // and environment variables; this is used when cargo calls us again in the CARGO_TARGET_RUNNER phase.
+        let env = CrateRunEnv::collect(args, inside_rustdoc);
+
+        store_json(CrateRunInfo::RunWith(env.clone()));
+
+        // Rustdoc expects us to exit with an error code if the test is marked as `compile_fail`,
+        // just creating the JSON file is not enough: we need to detect syntax errors,
+        // so we need to run Miri with `MIRI_BE_RUSTC` for a check-only build.
+        if inside_rustdoc {
+            let mut cmd = miri();
+
+            // Ensure --emit argument for a check-only build is present.
+            if let Some(val) =
+                ArgFlagValueIter::from_str_iter(env.args.iter().map(|s| s as &str), "--emit").next()
+            {
+                // For `no_run` tests, rustdoc passes a `--emit` flag; make sure it has the right shape.
+                assert_eq!(val, "metadata");
+            } else {
+                // For all other kinds of tests, we can just add our flag.
+                cmd.arg("--emit=metadata");
+            }
+
+            // Alter the `-o` parameter so that it does not overwrite the JSON file we stored above.
+            let mut args = env.args;
+            for i in 0..args.len() {
+                if args[i] == "-o" {
+                    args[i + 1].push_str(".miri");
+                }
+            }
+
+            cmd.args(&args);
+            cmd.env("MIRI_BE_RUSTC", "target");
+
+            if verbose > 0 {
+                eprintln!(
+                    "[cargo-miri rustc inside rustdoc] captured input:\n{}",
+                    std::str::from_utf8(&env.stdin).unwrap()
+                );
+                eprintln!("[cargo-miri rustc inside rustdoc] going to run:\n{:?}", cmd);
+            }
+
+            exec_with_pipe(cmd, &env.stdin, format!("{}.stdin", out_filename("", "").display()));
+        }
+
+        return;
+    }
+
+    if runnable_crate && get_arg_flag_values("--extern").any(|krate| krate == "proc_macro") {
+        // This is a "runnable" `proc-macro` crate (unit tests). We do not support
+        // interpreting that under Miri now, so we write a JSON file to (display a
+        // helpful message and) skip it in the runner phase.
+        store_json(CrateRunInfo::SkipProcMacroTest);
+        return;
+    }
+
+    let mut cmd = miri();
+    let mut emit_link_hack = false;
+    // Arguments are treated very differently depending on whether this crate is
+    // for interpretation by Miri, or for use by a build script / proc macro.
+    if !info_query && target_crate {
+        // Forward arguments, but remove "link" from "--emit" to make this a check-only build.
+        let emit_flag = "--emit";
+        while let Some(arg) = args.next() {
+            if let Some(val) = arg.strip_prefix(emit_flag) {
+                // Patch this argument. First, extract its value.
+                let val =
+                    val.strip_prefix('=').expect("`cargo` should pass `--emit=X` as one argument");
+                let mut val: Vec<_> = val.split(',').collect();
+                // Now make sure "link" is not in there, but "metadata" is.
+                if let Some(i) = val.iter().position(|&s| s == "link") {
+                    emit_link_hack = true;
+                    val.remove(i);
+                    if !val.iter().any(|&s| s == "metadata") {
+                        val.push("metadata");
+                    }
+                }
+                cmd.arg(format!("{}={}", emit_flag, val.join(",")));
+            } else if arg == "--extern" {
+                // Patch `--extern` filenames, since Cargo sometimes passes stub `.rlib` files:
+                // https://github.com/rust-lang/miri/issues/1705
+                forward_patched_extern_arg(&mut args, &mut cmd);
+            } else {
+                cmd.arg(arg);
+            }
+        }
+
+        // During setup, patch the panic runtime for `libpanic_abort` (mirroring what bootstrap usually does).
+        if phase == RustcPhase::Setup
+            && get_arg_flag_value("--crate-name").as_deref() == Some("panic_abort")
+        {
+            cmd.arg("-C").arg("panic=abort");
+        }
+    } else {
+        // For host crates (but not when we are just printing some info),
+        // we might still have to set the sysroot.
+        if !info_query {
+            // When we're running `cargo-miri` from `x.py` we need to pass the sysroot explicitly
+            // due to bootstrap complications.
+            if let Some(sysroot) = std::env::var_os("MIRI_HOST_SYSROOT") {
+                cmd.arg("--sysroot").arg(sysroot);
+            }
+        }
+
+        // For host crates or when we are printing, just forward everything.
+        cmd.args(args);
+    }
+
+    // We want to compile, not interpret. We still use Miri to make sure the compiler version etc
+    // are the exact same as what is used for interpretation.
+    // MIRI_DEFAULT_ARGS should not be used to build host crates, hence setting "target" or "host"
+    // as the value here to help Miri differentiate them.
+    cmd.env("MIRI_BE_RUSTC", if target_crate { "target" } else { "host" });
+
+    // Run it.
+    if verbose > 0 {
+        eprintln!(
+            "[cargo-miri rustc] target_crate={target_crate} runnable_crate={runnable_crate} info_query={info_query}"
+        );
+    }
+
+    // Create a stub .rlib file if "link" was requested by cargo.
+    // This is necessary to prevent cargo from doing rebuilds all the time.
+    if emit_link_hack {
+        // Some platforms prepend "lib", some do not... let's just create both files.
+        File::create(out_filename("lib", ".rlib")).expect("failed to create fake .rlib file");
+        File::create(out_filename("", ".rlib")).expect("failed to create fake .rlib file");
+        // Just in case this is a cdylib or staticlib, also create those fake files.
+        File::create(out_filename("lib", ".so")).expect("failed to create fake .so file");
+        File::create(out_filename("lib", ".a")).expect("failed to create fake .a file");
+        File::create(out_filename("lib", ".dylib")).expect("failed to create fake .dylib file");
+        File::create(out_filename("", ".dll")).expect("failed to create fake .dll file");
+        File::create(out_filename("", ".lib")).expect("failed to create fake .lib file");
+    }
+
+    debug_cmd("[cargo-miri rustc]", verbose, &cmd);
+    exec(cmd);
+}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum RunnerPhase {
+    /// `cargo` is running a binary
+    Cargo,
+    /// `rustdoc` is running a binary
+    Rustdoc,
+}
+
+pub fn phase_runner(mut binary_args: impl Iterator<Item = String>, phase: RunnerPhase) {
+    // phase_cargo_miri set `MIRI_BE_RUSTC` for when build scripts directly invoke the driver;
+    // however, if we get called back by cargo here, we'll carefully compute the right flags
+    // ourselves, so we first un-do what the earlier phase did.
+    env::remove_var("MIRI_BE_RUSTC");
+
+    let verbose = std::env::var("MIRI_VERBOSE")
+        .map_or(0, |verbose| verbose.parse().expect("verbosity flag must be an integer"));
+
+    let binary = binary_args.next().unwrap();
+    let file = File::open(&binary)
+        .unwrap_or_else(|_| show_error!(
+            "file {:?} not found or `cargo-miri` invoked incorrectly; please only invoke this binary through `cargo miri`", binary
+        ));
+    let file = BufReader::new(file);
+
+    let info = serde_json::from_reader(file).unwrap_or_else(|_| {
+        show_error!("file {:?} contains outdated or invalid JSON; try `cargo clean`", binary)
+    });
+    let info = match info {
+        CrateRunInfo::RunWith(info) => info,
+        CrateRunInfo::SkipProcMacroTest => {
+            eprintln!(
+                "Running unit tests of `proc-macro` crates is not currently supported by Miri."
+            );
+            return;
+        }
+    };
+
+    let mut cmd = miri();
+
+    // Set missing env vars. We prefer build-time env vars over run-time ones; see
+    // <https://github.com/rust-lang/miri/issues/1661> for the kind of issue that fixes.
+    for (name, val) in info.env {
+        if let Some(old_val) = env::var_os(&name) {
+            if old_val == val {
+                // This one did not actually change, no need to re-set it.
+                // (This keeps the `debug_cmd` below more manageable.)
+                continue;
+            } else if verbose > 0 {
+                eprintln!(
+                    "[cargo-miri runner] Overwriting run-time env var {:?}={:?} with build-time value {:?}",
+                    name, old_val, val
+                );
+            }
+        }
+        cmd.env(name, val);
+    }
+
+    // Forward rustc arguments.
+    // We need to patch "--extern" filenames because we forced a check-only
+    // build without cargo knowing about that: replace `.rlib` suffix by
+    // `.rmeta`.
+    // We also need to remove `--error-format` as cargo specifies that to be JSON,
+    // but when we run here, cargo does not interpret the JSON any more. `--json`
+    // then also nees to be dropped.
+    let mut args = info.args.into_iter();
+    let error_format_flag = "--error-format";
+    let json_flag = "--json";
+    while let Some(arg) = args.next() {
+        if arg == "--extern" {
+            forward_patched_extern_arg(&mut args, &mut cmd);
+        } else if let Some(suffix) = arg.strip_prefix(error_format_flag) {
+            assert!(suffix.starts_with('='));
+            // Drop this argument.
+        } else if let Some(suffix) = arg.strip_prefix(json_flag) {
+            assert!(suffix.starts_with('='));
+            // Drop this argument.
+        } else {
+            cmd.arg(arg);
+        }
+    }
+    // Respect `MIRIFLAGS`.
+    if let Ok(a) = env::var("MIRIFLAGS") {
+        // This code is taken from `RUSTFLAGS` handling in cargo.
+        let args = a.split(' ').map(str::trim).filter(|s| !s.is_empty()).map(str::to_string);
+        cmd.args(args);
+    }
+
+    // Then pass binary arguments.
+    cmd.arg("--");
+    cmd.args(binary_args);
+
+    // Make sure we use the build-time working directory for interpreting Miri/rustc arguments.
+    // But then we need to switch to the run-time one, which we instruct Miri do do by setting `MIRI_CWD`.
+    cmd.current_dir(info.current_dir);
+    cmd.env("MIRI_CWD", env::current_dir().unwrap());
+
+    // Run it.
+    debug_cmd("[cargo-miri runner]", verbose, &cmd);
+    match phase {
+        RunnerPhase::Rustdoc => exec_with_pipe(cmd, &info.stdin, format!("{}.stdin", binary)),
+        RunnerPhase::Cargo => exec(cmd),
+    }
+}
+
+pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
+    let verbose = std::env::var("MIRI_VERBOSE")
+        .map_or(0, |verbose| verbose.parse().expect("verbosity flag must be an integer"));
+
+    // phase_cargo_miri sets the RUSTDOC env var to ourselves, so we can't use that here;
+    // just default to a straight-forward invocation for now:
+    let mut cmd = Command::new("rustdoc");
+
+    let extern_flag = "--extern";
+    let runtool_flag = "--runtool";
+    while let Some(arg) = args.next() {
+        if arg == extern_flag {
+            // Patch --extern arguments to use *.rmeta files, since phase_cargo_rustc only creates stub *.rlib files.
+            forward_patched_extern_arg(&mut args, &mut cmd);
+        } else if arg == runtool_flag {
+            // An existing --runtool flag indicates cargo is running in cross-target mode, which we don't support.
+            // Note that this is only passed when cargo is run with the unstable -Zdoctest-xcompile flag;
+            // otherwise, we won't be called as rustdoc at all.
+            show_error!("cross-interpreting doctests is not currently supported by Miri.");
+        } else {
+            cmd.arg(arg);
+        }
+    }
+
+    // Doctests of `proc-macro` crates (and their dependencies) are always built for the host,
+    // so we are not able to run them in Miri.
+    if get_arg_flag_values("--crate-type").any(|crate_type| crate_type == "proc-macro") {
+        eprintln!("Running doctests of `proc-macro` crates is not currently supported by Miri.");
+        return;
+    }
+
+    // For each doctest, rustdoc starts two child processes: first the test is compiled,
+    // then the produced executable is invoked. We want to reroute both of these to cargo-miri,
+    // such that the first time we'll enter phase_cargo_rustc, and phase_cargo_runner second.
+    //
+    // rustdoc invokes the test-builder by forwarding most of its own arguments, which makes
+    // it difficult to determine when phase_cargo_rustc should run instead of phase_cargo_rustdoc.
+    // Furthermore, the test code is passed via stdin, rather than a temporary file, so we need
+    // to let phase_cargo_rustc know to expect that. We'll use this environment variable as a flag:
+    cmd.env("MIRI_CALLED_FROM_RUSTDOC", "1");
+
+    // The `--test-builder` and `--runtool` arguments are unstable rustdoc features,
+    // which are disabled by default. We first need to enable them explicitly:
+    cmd.arg("-Z").arg("unstable-options");
+
+    // rustdoc needs to know the right sysroot.
+    cmd.arg("--sysroot").arg(env::var_os("MIRI_SYSROOT").unwrap());
+    // make sure the 'miri' flag is set for rustdoc
+    cmd.arg("--cfg").arg("miri");
+
+    // Make rustdoc call us back.
+    let cargo_miri_path = std::env::current_exe().expect("current executable path invalid");
+    cmd.arg("--test-builder").arg(&cargo_miri_path); // invoked by forwarding most arguments
+    cmd.arg("--runtool").arg(&cargo_miri_path); // invoked with just a single path argument
+
+    debug_cmd("[cargo-miri rustdoc]", verbose, &cmd);
+    exec(cmd)
+}
diff --git a/src/tools/miri/cargo-miri/src/setup.rs b/src/tools/miri/cargo-miri/src/setup.rs
new file mode 100644
index 000000000000..c27bb1863175
--- /dev/null
+++ b/src/tools/miri/cargo-miri/src/setup.rs
@@ -0,0 +1,245 @@
+//! Implements `cargo miri setup` via xargo
+
+use std::env;
+use std::ffi::OsStr;
+use std::fs::{self};
+use std::io::BufRead;
+use std::ops::Not;
+use std::path::{Path, PathBuf};
+use std::process::{self, Command};
+
+use crate::{util::*, version::*};
+
+fn xargo_version() -> Option<(u32, u32, u32)> {
+    let out = xargo_check().arg("--version").output().ok()?;
+    if !out.status.success() {
+        return None;
+    }
+    // Parse output. The first line looks like "xargo 0.3.12 (b004f1c 2018-12-13)".
+    let line = out
+        .stderr
+        .lines()
+        .next()
+        .expect("malformed `xargo --version` output: not at least one line")
+        .expect("malformed `xargo --version` output: error reading first line");
+    let (name, version) = {
+        let mut split = line.split(' ');
+        (
+            split.next().expect("malformed `xargo --version` output: empty"),
+            split.next().expect("malformed `xargo --version` output: not at least two words"),
+        )
+    };
+    if name != "xargo" {
+        // This is some fork of xargo
+        return None;
+    }
+    let mut version_pieces = version.split('.');
+    let major = version_pieces
+        .next()
+        .expect("malformed `xargo --version` output: not a major version piece")
+        .parse()
+        .expect("malformed `xargo --version` output: major version is not an integer");
+    let minor = version_pieces
+        .next()
+        .expect("malformed `xargo --version` output: not a minor version piece")
+        .parse()
+        .expect("malformed `xargo --version` output: minor version is not an integer");
+    let patch = version_pieces
+        .next()
+        .expect("malformed `xargo --version` output: not a patch version piece")
+        .parse()
+        .expect("malformed `xargo --version` output: patch version is not an integer");
+    if version_pieces.next().is_some() {
+        panic!("malformed `xargo --version` output: more than three pieces in version");
+    }
+    Some((major, minor, patch))
+}
+
+/// Performs the setup required to make `cargo miri` work: Getting a custom-built libstd. Then sets
+/// `MIRI_SYSROOT`. Skipped if `MIRI_SYSROOT` is already set, in which case we expect the user has
+/// done all this already.
+pub fn setup(subcommand: &MiriCommand, host: &str, target: &str) {
+    let only_setup = matches!(subcommand, MiriCommand::Setup);
+    let ask_user = !only_setup;
+    let print_sysroot = only_setup && has_arg_flag("--print-sysroot"); // whether we just print the sysroot path
+    if std::env::var_os("MIRI_SYSROOT").is_some() {
+        if only_setup {
+            println!("WARNING: MIRI_SYSROOT already set, not doing anything.")
+        }
+        return;
+    }
+
+    // First, we need xargo.
+    if xargo_version().map_or(true, |v| v < XARGO_MIN_VERSION) {
+        if std::env::var_os("XARGO_CHECK").is_some() {
+            // The user manually gave us a xargo binary; don't do anything automatically.
+            show_error!("xargo is too old; please upgrade to the latest version")
+        }
+        let mut cmd = cargo();
+        cmd.args(["install", "xargo"]);
+        ask_to_run(cmd, ask_user, "install a recent enough xargo");
+    }
+
+    // Determine where the rust sources are located.  The env vars manually setting the source
+    // (`MIRI_LIB_SRC`, `XARGO_RUST_SRC`) trump auto-detection.
+    let rust_src_env_var =
+        std::env::var_os("MIRI_LIB_SRC").or_else(|| std::env::var_os("XARGO_RUST_SRC"));
+    let rust_src = match rust_src_env_var {
+        Some(path) => {
+            let path = PathBuf::from(path);
+            // Make path absolute if possible.
+            path.canonicalize().unwrap_or(path)
+        }
+        None => {
+            // Check for `rust-src` rustup component.
+            let output = miri_for_host()
+                .args(["--print", "sysroot"])
+                .output()
+                .expect("failed to determine sysroot");
+            if !output.status.success() {
+                show_error!(
+                    "Failed to determine sysroot; Miri said:\n{}",
+                    String::from_utf8_lossy(&output.stderr).trim_end()
+                );
+            }
+            let sysroot = std::str::from_utf8(&output.stdout).unwrap();
+            let sysroot = Path::new(sysroot.trim_end_matches('\n'));
+            // Check for `$SYSROOT/lib/rustlib/src/rust/library`; test if that contains `std/Cargo.toml`.
+            let rustup_src =
+                sysroot.join("lib").join("rustlib").join("src").join("rust").join("library");
+            if !rustup_src.join("std").join("Cargo.toml").exists() {
+                // Ask the user to install the `rust-src` component, and use that.
+                let mut cmd = Command::new("rustup");
+                cmd.args(["component", "add", "rust-src"]);
+                ask_to_run(
+                    cmd,
+                    ask_user,
+                    "install the `rust-src` component for the selected toolchain",
+                );
+            }
+            rustup_src
+        }
+    };
+    if !rust_src.exists() {
+        show_error!("given Rust source directory `{}` does not exist.", rust_src.display());
+    }
+    if rust_src.file_name().and_then(OsStr::to_str) != Some("library") {
+        show_error!(
+            "given Rust source directory `{}` does not seem to be the `library` subdirectory of \
+             a Rust source checkout.",
+            rust_src.display()
+        );
+    }
+
+    // Next, we need our own libstd. Prepare a xargo project for that purpose.
+    // We will do this work in whatever is a good cache dir for this platform.
+    let dirs = directories::ProjectDirs::from("org", "rust-lang", "miri").unwrap();
+    let dir = dirs.cache_dir();
+    if !dir.exists() {
+        fs::create_dir_all(dir).unwrap();
+    }
+    // The interesting bit: Xargo.toml (only needs content if we actually need std)
+    let xargo_toml = if std::env::var_os("MIRI_NO_STD").is_some() {
+        ""
+    } else {
+        r#"
+[dependencies.std]
+default_features = false
+# We support unwinding, so enable that panic runtime.
+features = ["panic_unwind", "backtrace"]
+
+[dependencies.test]
+"#
+    };
+    write_to_file(&dir.join("Xargo.toml"), xargo_toml);
+    // The boring bits: a dummy project for xargo.
+    // FIXME: With xargo-check, can we avoid doing this?
+    write_to_file(
+        &dir.join("Cargo.toml"),
+        r#"
+[package]
+name = "miri-xargo"
+description = "A dummy project for building libstd with xargo."
+version = "0.0.0"
+
+[lib]
+path = "lib.rs"
+"#,
+    );
+    write_to_file(&dir.join("lib.rs"), "#![no_std]");
+
+    // Figure out where xargo will build its stuff.
+    // Unfortunately, it puts things into a different directory when the
+    // architecture matches the host.
+    let sysroot = if target == host { dir.join("HOST") } else { PathBuf::from(dir) };
+    // Make sure all target-level Miri invocations know their sysroot.
+    std::env::set_var("MIRI_SYSROOT", &sysroot);
+
+    // Now invoke xargo.
+    let mut command = xargo_check();
+    command.arg("check").arg("-q");
+    command.current_dir(dir);
+    command.env("XARGO_HOME", dir);
+    command.env("XARGO_RUST_SRC", &rust_src);
+    // We always need to set a target so rustc bootstrap can tell apart host from target crates.
+    command.arg("--target").arg(target);
+    // Use Miri as rustc to build a libstd compatible with us (and use the right flags).
+    // However, when we are running in bootstrap, we cannot just overwrite `RUSTC`,
+    // because we still need bootstrap to distinguish between host and target crates.
+    // In that case we overwrite `RUSTC_REAL` instead which determines the rustc used
+    // for target crates.
+    // We set ourselves (`cargo-miri`) instead of Miri directly to be able to patch the flags
+    // for `libpanic_abort` (usually this is done by bootstrap but we have to do it ourselves).
+    // The `MIRI_CALLED_FROM_XARGO` will mean we dispatch to `phase_setup_rustc`.
+    let cargo_miri_path = std::env::current_exe().expect("current executable path invalid");
+    if env::var_os("RUSTC_STAGE").is_some() {
+        assert!(env::var_os("RUSTC").is_some());
+        command.env("RUSTC_REAL", &cargo_miri_path);
+    } else {
+        command.env("RUSTC", &cargo_miri_path);
+    }
+    command.env("MIRI_CALLED_FROM_XARGO", "1");
+    // Make sure there are no other wrappers getting in our way
+    // (Cc https://github.com/rust-lang/miri/issues/1421, https://github.com/rust-lang/miri/issues/2429).
+    // Looks like setting `RUSTC_WRAPPER` to the empty string overwrites `build.rustc-wrapper` set via `config.toml`.
+    command.env("RUSTC_WRAPPER", "");
+    // Disable debug assertions in the standard library -- Miri is already slow enough. But keep the
+    // overflow checks, they are cheap. This completely overwrites flags the user might have set,
+    // which is consistent with normal `cargo build` that does not apply `RUSTFLAGS` to the sysroot
+    // either.
+    command.env("RUSTFLAGS", "-Cdebug-assertions=off -Coverflow-checks=on");
+    // Manage the output the user sees.
+    if only_setup {
+        // We want to be explicit.
+        eprintln!("Preparing a sysroot for Miri (target: {target})...");
+        if print_sysroot {
+            // Be extra sure there is no noise on stdout.
+            command.stdout(process::Stdio::null());
+        }
+    } else {
+        // We want to be quiet, but still let the user know that something is happening.
+        eprint!("Preparing a sysroot for Miri (target: {target})... ");
+        command.stdout(process::Stdio::null());
+        command.stderr(process::Stdio::null());
+    }
+
+    // Finally run it!
+    if command.status().expect("failed to run xargo").success().not() {
+        if only_setup {
+            show_error!("failed to run xargo, see error details above")
+        } else {
+            show_error!("failed to run xargo; run `cargo miri setup` to see the error details")
+        }
+    }
+
+    // Figure out what to print.
+    if only_setup {
+        eprintln!("A sysroot for Miri is now available in `{}`.", sysroot.display());
+    } else {
+        eprintln!("done");
+    }
+    if print_sysroot {
+        // Print just the sysroot and nothing else to stdout; this way we do not need any escaping.
+        println!("{}", sysroot.display());
+    }
+}
diff --git a/src/tools/miri/cargo-miri/src/util.rs b/src/tools/miri/cargo-miri/src/util.rs
new file mode 100644
index 000000000000..8f29eebaac10
--- /dev/null
+++ b/src/tools/miri/cargo-miri/src/util.rs
@@ -0,0 +1,314 @@
+use std::collections::HashMap;
+use std::env;
+use std::ffi::OsString;
+use std::fmt::Write as _;
+use std::fs::{self, File};
+use std::io::{self, BufWriter, Read, Write};
+use std::ops::Not;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+use cargo_metadata::{Metadata, MetadataCommand};
+use rustc_version::VersionMeta;
+use serde::{Deserialize, Serialize};
+
+pub use crate::arg::*;
+
+pub fn show_error(msg: &impl std::fmt::Display) -> ! {
+    eprintln!("fatal error: {msg}");
+    std::process::exit(1)
+}
+
+macro_rules! show_error {
+    ($($tt:tt)*) => { crate::util::show_error(&format_args!($($tt)*)) };
+}
+
+/// The information to run a crate with the given environment.
+#[derive(Clone, Serialize, Deserialize)]
+pub struct CrateRunEnv {
+    /// The command-line arguments.
+    pub args: Vec<String>,
+    /// The environment.
+    pub env: Vec<(OsString, OsString)>,
+    /// The current working directory.
+    pub current_dir: OsString,
+    /// The contents passed via standard input.
+    pub stdin: Vec<u8>,
+}
+
+impl CrateRunEnv {
+    /// Gather all the information we need.
+    pub fn collect(args: impl Iterator<Item = String>, capture_stdin: bool) -> Self {
+        let args = args.collect();
+        let env = env::vars_os().collect();
+        let current_dir = env::current_dir().unwrap().into_os_string();
+
+        let mut stdin = Vec::new();
+        if capture_stdin {
+            std::io::stdin().lock().read_to_end(&mut stdin).expect("cannot read stdin");
+        }
+
+        CrateRunEnv { args, env, current_dir, stdin }
+    }
+}
+
+/// The information Miri needs to run a crate. Stored as JSON when the crate is "compiled".
+#[derive(Serialize, Deserialize)]
+pub enum CrateRunInfo {
+    /// Run it with the given environment.
+    RunWith(CrateRunEnv),
+    /// Skip it as Miri does not support interpreting such kind of crates.
+    SkipProcMacroTest,
+}
+
+impl CrateRunInfo {
+    pub fn store(&self, filename: &Path) {
+        let file = File::create(filename)
+            .unwrap_or_else(|_| show_error!("cannot create `{}`", filename.display()));
+        let file = BufWriter::new(file);
+        serde_json::ser::to_writer(file, self)
+            .unwrap_or_else(|_| show_error!("cannot write to `{}`", filename.display()));
+    }
+}
+
+#[derive(Clone, Debug)]
+pub enum MiriCommand {
+    /// Our own special 'setup' command.
+    Setup,
+    /// A command to be forwarded to cargo.
+    Forward(String),
+}
+
+/// Escapes `s` in a way that is suitable for using it as a string literal in TOML syntax.
+pub fn escape_for_toml(s: &str) -> String {
+    // We want to surround this string in quotes `"`. So we first escape all quotes,
+    // and also all backslashes (that are used to escape quotes).
+    let s = s.replace('\\', r#"\\"#).replace('"', r#"\""#);
+    format!("\"{}\"", s)
+}
+
+/// Returns the path to the `miri` binary
+pub fn find_miri() -> PathBuf {
+    if let Some(path) = env::var_os("MIRI") {
+        return path.into();
+    }
+    let mut path = std::env::current_exe().expect("current executable path invalid");
+    if cfg!(windows) {
+        path.set_file_name("miri.exe");
+    } else {
+        path.set_file_name("miri");
+    }
+    path
+}
+
+pub fn miri() -> Command {
+    Command::new(find_miri())
+}
+
+pub fn miri_for_host() -> Command {
+    let mut cmd = miri();
+    cmd.env("MIRI_BE_RUSTC", "host");
+    cmd
+}
+
+pub fn version_info() -> VersionMeta {
+    VersionMeta::for_command(miri_for_host())
+        .expect("failed to determine underlying rustc version of Miri")
+}
+
+pub fn cargo() -> Command {
+    Command::new(env::var_os("CARGO").unwrap_or_else(|| OsString::from("cargo")))
+}
+
+pub fn xargo_check() -> Command {
+    Command::new(env::var_os("XARGO_CHECK").unwrap_or_else(|| OsString::from("xargo-check")))
+}
+
+/// Execute the `Command`, where possible by replacing the current process with a new process
+/// described by the `Command`. Then exit this process with the exit code of the new process.
+pub fn exec(mut cmd: Command) -> ! {
+    // On non-Unix imitate POSIX exec as closely as we can
+    #[cfg(not(unix))]
+    {
+        let exit_status = cmd.status().expect("failed to run command");
+        std::process::exit(exit_status.code().unwrap_or(-1))
+    }
+    // On Unix targets, actually exec.
+    // If exec returns, process setup has failed. This is the same error condition as the expect in
+    // the non-Unix case.
+    #[cfg(unix)]
+    {
+        use std::os::unix::process::CommandExt;
+        let error = cmd.exec();
+        Err(error).expect("failed to run command")
+    }
+}
+
+/// Execute the `Command`, where possible by replacing the current process with a new process
+/// described by the `Command`. Then exit this process with the exit code of the new process.
+/// `input` is also piped to the new process's stdin, on cfg(unix) platforms by writing its
+/// contents to `path` first, then setting stdin to that file.
+pub fn exec_with_pipe<P>(mut cmd: Command, input: &[u8], path: P) -> !
+where
+    P: AsRef<Path>,
+{
+    #[cfg(unix)]
+    {
+        // Write the bytes we want to send to stdin out to a file
+        std::fs::write(&path, input).unwrap();
+        // Open the file for reading, and set our new stdin to it
+        let stdin = File::open(&path).unwrap();
+        cmd.stdin(stdin);
+        // Unlink the file so that it is fully cleaned up as soon as the new process exits
+        std::fs::remove_file(&path).unwrap();
+        // Finally, we can hand off control.
+        exec(cmd)
+    }
+    #[cfg(not(unix))]
+    {
+        drop(path); // We don't need the path, we can pipe the bytes directly
+        cmd.stdin(std::process::Stdio::piped());
+        let mut child = cmd.spawn().expect("failed to spawn process");
+        {
+            let stdin = child.stdin.as_mut().expect("failed to open stdin");
+            stdin.write_all(input).expect("failed to write out test source");
+        }
+        let exit_status = child.wait().expect("failed to run command");
+        std::process::exit(exit_status.code().unwrap_or(-1))
+    }
+}
+
+pub fn ask_to_run(mut cmd: Command, ask: bool, text: &str) {
+    // Disable interactive prompts in CI (GitHub Actions, Travis, AppVeyor, etc).
+    // Azure doesn't set `CI` though (nothing to see here, just Microsoft being Microsoft),
+    // so we also check their `TF_BUILD`.
+    let is_ci = env::var_os("CI").is_some() || env::var_os("TF_BUILD").is_some();
+    if ask && !is_ci {
+        let mut buf = String::new();
+        print!("I will run `{:?}` to {}. Proceed? [Y/n] ", cmd, text);
+        io::stdout().flush().unwrap();
+        io::stdin().read_line(&mut buf).unwrap();
+        match buf.trim().to_lowercase().as_ref() {
+            // Proceed.
+            "" | "y" | "yes" => {}
+            "n" | "no" => show_error!("aborting as per your request"),
+            a => show_error!("invalid answer `{}`", a),
+        };
+    } else {
+        eprintln!("Running `{:?}` to {}.", cmd, text);
+    }
+
+    if cmd.status().unwrap_or_else(|_| panic!("failed to execute {:?}", cmd)).success().not() {
+        show_error!("failed to {}", text);
+    }
+}
+
+/// Writes the given content to the given file *cross-process atomically*, in the sense that another
+/// process concurrently reading that file will see either the old content or the new content, but
+/// not some intermediate (e.g., empty) state.
+///
+/// We assume no other parts of this same process are trying to read or write that file.
+pub fn write_to_file(filename: &Path, content: &str) {
+    // Create a temporary file with the desired contents.
+    let mut temp_filename = filename.as_os_str().to_os_string();
+    temp_filename.push(&format!(".{}", std::process::id()));
+    let mut temp_file = File::create(&temp_filename).unwrap();
+    temp_file.write_all(content.as_bytes()).unwrap();
+    drop(temp_file);
+
+    // Move file to the desired location.
+    fs::rename(temp_filename, filename).unwrap();
+}
+
+// Computes the extra flags that need to be passed to cargo to make it behave like the current
+// cargo invocation.
+fn cargo_extra_flags() -> Vec<String> {
+    let mut flags = Vec::new();
+    // `-Zunstable-options` is required by `--config`.
+    flags.push("-Zunstable-options".to_string());
+
+    // Forward `--config` flags.
+    let config_flag = "--config";
+    for arg in get_arg_flag_values(config_flag) {
+        flags.push(config_flag.to_string());
+        flags.push(arg);
+    }
+
+    // Forward `--manifest-path`.
+    let manifest_flag = "--manifest-path";
+    if let Some(manifest) = get_arg_flag_value(manifest_flag) {
+        flags.push(manifest_flag.to_string());
+        flags.push(manifest);
+    }
+
+    // Forwarding `--target-dir` would make sense, but `cargo metadata` does not support that flag.
+
+    flags
+}
+
+pub fn get_cargo_metadata() -> Metadata {
+    // This will honor the `CARGO` env var the same way our `cargo()` does.
+    MetadataCommand::new().no_deps().other_options(cargo_extra_flags()).exec().unwrap()
+}
+
+/// Pulls all the crates in this workspace from the cargo metadata.
+/// Workspace members are emitted like "miri 0.1.0 (path+file:///path/to/miri)"
+/// Additionally, somewhere between cargo metadata and TyCtxt, '-' gets replaced with '_' so we
+/// make that same transformation here.
+pub fn local_crates(metadata: &Metadata) -> String {
+    assert!(!metadata.workspace_members.is_empty());
+    let mut local_crates = String::new();
+    for member in &metadata.workspace_members {
+        let name = member.repr.split(' ').next().unwrap();
+        let name = name.replace('-', "_");
+        local_crates.push_str(&name);
+        local_crates.push(',');
+    }
+    local_crates.pop(); // Remove the trailing ','
+
+    local_crates
+}
+
+fn env_vars_from_cmd(cmd: &Command) -> Vec<(String, String)> {
+    let mut envs = HashMap::new();
+    for (key, value) in std::env::vars() {
+        envs.insert(key, value);
+    }
+    for (key, value) in cmd.get_envs() {
+        if let Some(value) = value {
+            envs.insert(key.to_string_lossy().to_string(), value.to_string_lossy().to_string());
+        } else {
+            envs.remove(&key.to_string_lossy().to_string());
+        }
+    }
+    let mut envs: Vec<_> = envs.into_iter().collect();
+    envs.sort();
+    envs
+}
+
+/// Debug-print a command that is going to be run.
+pub fn debug_cmd(prefix: &str, verbose: usize, cmd: &Command) {
+    if verbose == 0 {
+        return;
+    }
+    // We only do a single `eprintln!` call to minimize concurrency interactions.
+    let mut out = prefix.to_string();
+    writeln!(out, " running command: env \\").unwrap();
+    if verbose > 1 {
+        // Print the full environment this will be called in.
+        for (key, value) in env_vars_from_cmd(cmd) {
+            writeln!(out, "{key}={value:?} \\").unwrap();
+        }
+    } else {
+        // Print only what has been changed for this `cmd`.
+        for (var, val) in cmd.get_envs() {
+            if let Some(val) = val {
+                writeln!(out, "{}={:?} \\", var.to_string_lossy(), val).unwrap();
+            } else {
+                writeln!(out, "--unset={}", var.to_string_lossy()).unwrap();
+            }
+        }
+    }
+    write!(out, "{cmd:?}").unwrap();
+    eprintln!("{}", out);
+}
diff --git a/src/tools/miri/cargo-miri/src/version.rs b/src/tools/miri/cargo-miri/src/version.rs
new file mode 100644
index 000000000000..366e90df1798
--- /dev/null
+++ b/src/tools/miri/cargo-miri/src/version.rs
@@ -0,0 +1,2 @@
+// We put this in a separate file so that it can be hashed for GHA caching.
+pub const XARGO_MIN_VERSION: (u32, u32, u32) = (0, 3, 26);
diff --git a/src/tools/miri/ci.sh b/src/tools/miri/ci.sh
new file mode 100755
index 000000000000..aa322e54a31d
--- /dev/null
+++ b/src/tools/miri/ci.sh
@@ -0,0 +1,101 @@
+#!/bin/bash
+set -euo pipefail
+set -x
+
+# Determine configuration for installed build
+echo "Installing release version of Miri"
+export RUSTFLAGS="-D warnings"
+export CARGO_INCREMENTAL=0
+./miri install # implicitly locked
+
+# Prepare debug build for direct `./miri` invocations
+echo "Building debug version of Miri"
+export CARGO_EXTRA_FLAGS="--locked"
+./miri check --no-default-features # make sure this can be built
+./miri check --all-features # and this, too
+./miri build --all-targets # the build that all the `./miri test` below will use
+echo
+
+# Test
+function run_tests {
+  if [ -n "${MIRI_TEST_TARGET+exists}" ]; then
+    echo "Testing foreign architecture $MIRI_TEST_TARGET"
+  else
+    echo "Testing host architecture"
+  fi
+
+  ## ui test suite
+  ./miri test
+  if [ -z "${MIRI_TEST_TARGET+exists}" ]; then
+    # Only for host architecture: tests with optimizations (`-O` is what cargo passes, but crank MIR
+    # optimizations up all the way).
+    # Optimizations change diagnostics (mostly backtraces), so we don't check them
+    #FIXME(#2155): we want to only run the pass and panic tests here, not the fail tests.
+    MIRIFLAGS="${MIRIFLAGS:-} -O -Zmir-opt-level=4" MIRI_SKIP_UI_CHECKS=1 ./miri test -- tests/{pass,panic}
+  fi
+
+  ## test-cargo-miri
+  # On Windows, there is always "python", not "python3" or "python2".
+  if command -v python3 > /dev/null; then
+    PYTHON=python3
+  else
+    PYTHON=python
+  fi
+  # Some environment setup that attempts to confuse the heck out of cargo-miri.
+  if [ "$HOST_TARGET" = x86_64-unknown-linux-gnu ]; then
+    # These act up on Windows (`which miri` produces a filename that does not exist?!?),
+    # so let's do this only on Linux. Also makes sure things work without these set.
+    export RUSTC=$(which rustc)
+    export MIRI=$(which miri)
+  fi
+  mkdir -p .cargo
+  echo 'build.rustc-wrapper = "thisdoesnotexist"' > .cargo/config.toml
+  # Run the actual test
+  ${PYTHON} test-cargo-miri/run-test.py
+  echo
+  # Clean up
+  unset RUSTC MIRI
+  rm -rf .cargo
+
+  # Ensure that our benchmarks all work, but only on Linux hosts.
+  if [ -z "${MIRI_TEST_TARGET+exists}" ] && [ "$HOST_TARGET" = x86_64-unknown-linux-gnu ] ; then
+    for BENCH in $(ls "bench-cargo-miri"); do
+      cargo miri run --manifest-path bench-cargo-miri/$BENCH/Cargo.toml
+    done
+  fi
+}
+
+function run_tests_minimal {
+  if [ -n "${MIRI_TEST_TARGET+exists}" ]; then
+    echo "Testing MINIMAL foreign architecture $MIRI_TEST_TARGET: only testing $@"
+  else
+    echo "Testing MINIMAL host architecture: only testing $@"
+  fi
+
+  ./miri test -- "$@"
+}
+
+# host
+run_tests
+
+case $HOST_TARGET in
+  x86_64-unknown-linux-gnu)
+    MIRI_TEST_TARGET=i686-unknown-linux-gnu run_tests
+    MIRI_TEST_TARGET=aarch64-apple-darwin run_tests
+    MIRI_TEST_TARGET=i686-pc-windows-msvc run_tests
+    MIRI_TEST_TARGET=x86_64-unknown-freebsd run_tests_minimal hello integer vec panic/panic concurrency/simple atomic data_race env/var
+    MIRI_TEST_TARGET=aarch64-linux-android run_tests_minimal hello integer vec panic/panic
+    MIRI_TEST_TARGET=thumbv7em-none-eabihf MIRI_NO_STD=1 run_tests_minimal no_std # no_std embedded architecture
+    ;;
+  x86_64-apple-darwin)
+    MIRI_TEST_TARGET=mips64-unknown-linux-gnuabi64 run_tests # big-endian architecture
+    MIRI_TEST_TARGET=x86_64-pc-windows-msvc run_tests
+    ;;
+  i686-pc-windows-msvc)
+    MIRI_TEST_TARGET=x86_64-unknown-linux-gnu run_tests
+    ;;
+  *)
+    echo "FATAL: unknown OS"
+    exit 1
+    ;;
+esac
diff --git a/src/tools/miri/miri b/src/tools/miri/miri
new file mode 100755
index 000000000000..19f1a987ace4
--- /dev/null
+++ b/src/tools/miri/miri
@@ -0,0 +1,236 @@
+#!/bin/bash
+set -e
+USAGE=$(cat <<"EOF"
+  COMMANDS
+
+./miri install <flags>:
+Installs the miri driver and cargo-miri. <flags> are passed to `cargo
+install`. Sets up the rpath such that the installed binary should work in any
+working directory. However, the rustup toolchain when invoking `cargo miri`
+needs to be the same one used for `./miri install`.
+
+./miri build <flags>:
+Just build miri. <flags> are passed to `cargo build`.
+
+./miri check <flags>:
+Just check miri. <flags> are passed to `cargo check`.
+
+./miri test <flags>:
+Build miri, set up a sysroot and then run the test suite. <flags> are passed
+to the final `cargo test` invocation.
+
+./miri run <flags>:
+Build miri, set up a sysroot and then run the driver with the given <flags>.
+(Also respects MIRIFLAGS environment variable.)
+
+./miri fmt <flags>:
+Format all sources and tests. <flags> are passed to `rustfmt`.
+
+./miri clippy <flags>:
+Runs clippy on all sources. <flags> are passed to `cargo clippy`.
+
+./miri cargo <flags>:
+Runs just `cargo <flags>` with the Miri-specific environment variables.
+Mainly meant to be invoked by rust-analyzer.
+
+./miri many-seeds <command>:
+Runs <command> over and over again with different seeds for Miri. The MIRIFLAGS
+variable is set to its original value appended with ` -Zmiri-seed=$SEED` for
+many different seeds.
+
+./miri bench <benches>:
+Runs the benchmarks from bench-cargo-miri in hyperfine. hyperfine needs to be installed.
+<benches> can explicitly list the benchmarks to run; by default, all of them are run.
+
+  ENVIRONMENT VARIABLES
+
+MIRI_SYSROOT:
+If already set, the "sysroot setup" step is skipped.
+
+CARGO_EXTRA_FLAGS:
+Pass extra flags to all cargo invocations. (Ignored by `./miri cargo`.)
+EOF
+)
+
+## We need to know where we are.
+# macOS does not have a useful readlink/realpath so we have to use Python instead...
+MIRIDIR=$(python3 -c 'import os, sys; print(os.path.dirname(os.path.realpath(sys.argv[1])))' "$0")
+
+## Run the auto-things.
+if [ -z "$MIRI_AUTO_OPS" ]; then
+    export MIRI_AUTO_OPS=42
+
+    # Run this first, so that the toolchain doesn't change after
+    # other code has run.
+    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-toolchain" ] ; then
+        (cd "$MIRIDIR" && ./rustup-toolchain)
+    fi
+
+    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-fmt" ] ; then
+        $0 fmt
+    fi
+
+    if [ -f "$MIRIDIR/.auto-everything" ] || [ -f "$MIRIDIR/.auto-clippy" ] ; then
+        $0 clippy -- -D warnings
+    fi
+fi
+
+## Determine command and toolchain.
+COMMAND="$1"
+[ $# -gt 0 ] && shift
+# Doing this *after* auto-toolchain logic above, since that might change the toolchain.
+TOOLCHAIN=$(cd "$MIRIDIR"; rustup show active-toolchain | head -n 1 | cut -d ' ' -f 1)
+
+## Handle some commands early, since they should *not* alter the environment.
+case "$COMMAND" in
+many-seeds)
+    for SEED in $({ echo obase=16; seq 0 255; } | bc); do
+        echo "Trying seed: $SEED"
+        MIRIFLAGS="$MIRIFLAGS -Zmiri-seed=$SEED" $@ || { echo "Failing seed: $SEED"; break; }
+    done
+    exit 0
+    ;;
+bench)
+    # Make sure we have an up-to-date Miri installed
+    "$0" install
+    # Run the requested benchmarks
+    if [ -z "${1+exists}" ]; then
+        BENCHES=( $(ls "$MIRIDIR/bench-cargo-miri" ) )
+    else
+        BENCHES=("$@")
+    fi
+    for BENCH in "${BENCHES[@]}"; do
+        hyperfine -w 1 -m 5 --shell=none "cargo +$TOOLCHAIN miri run --manifest-path $MIRIDIR/bench-cargo-miri/$BENCH/Cargo.toml"
+    done
+    exit 0
+    ;;
+esac
+
+## Prepare the environment
+# Determine some toolchain properties
+# export the target so its available in miri
+TARGET=$(rustc +$TOOLCHAIN --version --verbose | grep "^host:" | cut -d ' ' -f 2)
+SYSROOT=$(rustc +$TOOLCHAIN --print sysroot)
+LIBDIR=$SYSROOT/lib/rustlib/$TARGET/lib
+if ! test -d "$LIBDIR"; then
+    echo "Something went wrong determining the library dir."
+    echo "I got $LIBDIR but that does not exist."
+    echo "Please report a bug at https://github.com/rust-lang/miri/issues."
+    exit 2
+fi
+
+# Prepare flags for cargo and rustc.
+CARGO="cargo +$TOOLCHAIN"
+# Share target dir between `miri` and `cargo-miri`.
+if [ -z "$CARGO_TARGET_DIR" ]; then
+    export CARGO_TARGET_DIR="$MIRIDIR/target"
+fi
+# We configure dev builds to not be unusably slow.
+if [ -z "$CARGO_PROFILE_DEV_OPT_LEVEL" ]; then
+    export CARGO_PROFILE_DEV_OPT_LEVEL=2
+fi
+# Enable rustc-specific lints (ignored without `-Zunstable-options`).
+export RUSTFLAGS="-Zunstable-options -Wrustc::internal $RUSTFLAGS"
+# We set the rpath so that Miri finds the private rustc libraries it needs.
+export RUSTFLAGS="-C link-args=-Wl,-rpath,$LIBDIR $RUSTFLAGS"
+
+## Helper functions
+
+# Build a sysroot and set MIRI_SYSROOT to use it. Arguments are passed to `cargo miri setup`.
+build_sysroot() {
+    if ! MIRI_SYSROOT="$($CARGO run $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/cargo-miri/Cargo.toml -q -- miri setup --print-sysroot "$@")"; then
+        echo "'cargo miri setup' failed"
+        exit 1
+    fi
+    export MIRI_SYSROOT
+}
+
+# Prepare and set MIRI_SYSROOT. Respects `MIRI_TEST_TARGET` and takes into account
+# locally built vs. distributed rustc.
+find_sysroot() {
+    if [ -n "$MIRI_SYSROOT" ]; then
+        # Sysroot already set, use that.
+        return 0
+    fi
+    # We need to build a sysroot.
+    if [ -n "$MIRI_TEST_TARGET" ]; then
+        build_sysroot --target "$MIRI_TEST_TARGET"
+    else
+        build_sysroot
+    fi
+}
+
+## Main
+
+# Run command.
+case "$COMMAND" in
+install)
+    # "--locked" to respect the Cargo.lock file if it exists.
+    $CARGO install $CARGO_EXTRA_FLAGS --path "$MIRIDIR" --force --locked "$@"
+    $CARGO install $CARGO_EXTRA_FLAGS --path "$MIRIDIR"/cargo-miri --force --locked "$@"
+    ;;
+check)
+    # Check, and let caller control flags.
+    $CARGO check $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml --all-targets "$@"
+    $CARGO check $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/cargo-miri/Cargo.toml "$@"
+    ;;
+build)
+    # Build, and let caller control flags.
+    $CARGO build $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml "$@"
+    $CARGO build $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/cargo-miri/Cargo.toml "$@"
+    ;;
+test|bless)
+    # First build and get a sysroot.
+    $CARGO build $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml
+    find_sysroot
+    if [ "$COMMAND" = "bless" ]; then
+        export MIRI_BLESS="Gesundheit"
+    fi
+    # Then test, and let caller control flags.
+    # Only in root project as `cargo-miri` has no tests.
+    $CARGO test $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml "$@"
+    ;;
+run)
+    # Scan for "--target" to overwrite the "MIRI_TEST_TARGET" env var so
+    # that we set the MIRI_SYSROOT up the right way.
+    FOUND_TARGET_OPT=0
+    for ARG in "$@"; do
+        if [ "$LAST_ARG" = "--target" ]; then
+            # Found it!
+            export MIRI_TEST_TARGET="$ARG"
+            FOUND_TARGET_OPT=1
+            break
+        fi
+        LAST_ARG="$ARG"
+    done
+    if [ "$FOUND_TARGET_OPT" = "0" ] && [ -n "$MIRI_TEST_TARGET" ]; then
+        # Make sure Miri actually uses this target.
+        MIRIFLAGS="$MIRIFLAGS --target $MIRI_TEST_TARGET"
+    fi
+    # First build and get a sysroot.
+    $CARGO build $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml
+    find_sysroot
+    # Then run the actual command.
+    exec $CARGO run $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml -- $MIRIFLAGS "$@"
+    ;;
+fmt)
+    find "$MIRIDIR" -not \( -name target -prune \) -name '*.rs' \
+        | xargs rustfmt +$TOOLCHAIN --edition=2021 --config-path "$MIRIDIR/rustfmt.toml" "$@"
+    ;;
+clippy)
+    $CARGO clippy $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/Cargo.toml --all-targets "$@"
+    $CARGO clippy $CARGO_EXTRA_FLAGS --manifest-path "$MIRIDIR"/cargo-miri/Cargo.toml "$@"
+    ;;
+cargo)
+    # We carefully kept the working dir intact, so this will run cargo *on the workspace in the
+    # current working dir*, not on the main Miri workspace. That is exactly what RA needs.
+    $CARGO "$@"
+    ;;
+*)
+    if [ -n "$COMMAND" ]; then
+      echo "Unknown command: $COMMAND"
+      echo
+    fi
+    echo "$USAGE"
+    exit 1
+esac
diff --git a/src/tools/miri/rust-version b/src/tools/miri/rust-version
new file mode 100644
index 000000000000..78b9a110aa7c
--- /dev/null
+++ b/src/tools/miri/rust-version
@@ -0,0 +1 @@
+acb8934fd57b3c2740c4abac0a5728c2c9b1423b
diff --git a/src/tools/miri/rustfmt.toml b/src/tools/miri/rustfmt.toml
new file mode 100644
index 000000000000..be5af7379eae
--- /dev/null
+++ b/src/tools/miri/rustfmt.toml
@@ -0,0 +1,5 @@
+version = "Two"
+use_small_heuristics = "Max"
+match_arm_blocks = false
+match_arm_leading_pipes = "Preserve"
+force_multiline_blocks = true
diff --git a/src/tools/miri/rustup-toolchain b/src/tools/miri/rustup-toolchain
new file mode 100755
index 000000000000..d7730f2b06d3
--- /dev/null
+++ b/src/tools/miri/rustup-toolchain
@@ -0,0 +1,53 @@
+#!/bin/bash
+set -e
+# Manages a rustup toolchain called "miri".
+#
+# All commands set "miri" as the override toolchain for the current directory,
+# and make the `rust-version` file match that toolchain.
+#
+# USAGE:
+#
+# ./rustup-toolchain: Update "miri" toolchain to match `rust-version` (the known-good version for this commit).
+#
+# ./rustup-toolchain HEAD: Update "miri" toolchain and `rust-version` file to latest rustc HEAD.
+#
+# ./rustup-toolchain $COMMIT: Update "miri" toolchain and `rust-version` file to match that commit.
+#
+# Any extra parameters are passed to `rustup-toolchain-install-master`.
+
+# Make sure rustup-toolchain-install-master is installed.
+if ! which rustup-toolchain-install-master >/dev/null; then
+    echo "Please install rustup-toolchain-install-master by running 'cargo install rustup-toolchain-install-master'"
+    exit 1
+fi
+
+# Determine new commit.
+if [[ "$1" == "" ]]; then
+    NEW_COMMIT=$(cat rust-version)
+elif [[ "$1" == "HEAD" ]]; then
+    NEW_COMMIT=$(git ls-remote https://github.com/rust-lang/rust/ HEAD | cut -f 1)
+else
+    NEW_COMMIT="$1"
+fi
+echo "$NEW_COMMIT" > rust-version
+shift || true # don't fail if shifting fails
+
+# Check if we already are at that commit.
+CUR_COMMIT=$(rustc +miri --version -v 2>/dev/null | grep "^commit-hash: " | cut -d " " -f 2)
+if [[ "$CUR_COMMIT" == "$NEW_COMMIT" ]]; then
+    echo "miri toolchain is already at commit $CUR_COMMIT."
+    rustup override set miri
+    exit 0
+fi
+
+# Install and setup new toolchain.
+rustup toolchain uninstall miri
+rustup-toolchain-install-master -n miri -c cargo -c rust-src -c rustc-dev -c llvm-tools -c rustfmt -c clippy "$@" -- "$NEW_COMMIT"
+rustup override set miri
+
+# Cleanup.
+cargo clean
+
+# Call 'cargo metadata' on the sources in case that changes the lockfile
+# (which fails under some setups when it is done from inside vscode).
+cargo metadata --format-version 1 --manifest-path "$(rustc --print sysroot)/lib/rustlib/rustc-src/rust/compiler/rustc/Cargo.toml" >/dev/null
diff --git a/src/tools/miri/src/bin/miri.rs b/src/tools/miri/src/bin/miri.rs
new file mode 100644
index 000000000000..7d32ee425732
--- /dev/null
+++ b/src/tools/miri/src/bin/miri.rs
@@ -0,0 +1,562 @@
+#![feature(rustc_private, stmt_expr_attributes)]
+#![allow(
+    clippy::manual_range_contains,
+    clippy::useless_format,
+    clippy::field_reassign_with_default
+)]
+
+extern crate rustc_data_structures;
+extern crate rustc_driver;
+extern crate rustc_hir;
+extern crate rustc_interface;
+extern crate rustc_metadata;
+extern crate rustc_middle;
+extern crate rustc_session;
+
+use std::env;
+use std::num::NonZeroU64;
+use std::path::PathBuf;
+use std::str::FromStr;
+
+use log::debug;
+
+use rustc_data_structures::sync::Lrc;
+use rustc_driver::Compilation;
+use rustc_hir::{self as hir, def_id::LOCAL_CRATE, Node};
+use rustc_interface::interface::Config;
+use rustc_middle::{
+    middle::exported_symbols::{
+        ExportedSymbol, SymbolExportInfo, SymbolExportKind, SymbolExportLevel,
+    },
+    ty::{query::ExternProviders, TyCtxt},
+};
+use rustc_session::{config::CrateType, search_paths::PathKind, CtfeBacktrace};
+
+use miri::{BacktraceStyle, ProvenanceMode};
+
+struct MiriCompilerCalls {
+    miri_config: miri::MiriConfig,
+}
+
+impl rustc_driver::Callbacks for MiriCompilerCalls {
+    fn config(&mut self, config: &mut Config) {
+        config.override_queries = Some(|_, _, external_providers| {
+            external_providers.used_crate_source = |tcx, cnum| {
+                let mut providers = ExternProviders::default();
+                rustc_metadata::provide_extern(&mut providers);
+                let mut crate_source = (providers.used_crate_source)(tcx, cnum);
+                // HACK: rustc will emit "crate ... required to be available in rlib format, but
+                // was not found in this form" errors once we use `tcx.dependency_formats()` if
+                // there's no rlib provided, so setting a dummy path here to workaround those errors.
+                Lrc::make_mut(&mut crate_source).rlib = Some((PathBuf::new(), PathKind::All));
+                crate_source
+            };
+        });
+    }
+
+    fn after_analysis<'tcx>(
+        &mut self,
+        compiler: &rustc_interface::interface::Compiler,
+        queries: &'tcx rustc_interface::Queries<'tcx>,
+    ) -> Compilation {
+        compiler.session().abort_if_errors();
+
+        queries.global_ctxt().unwrap().peek_mut().enter(|tcx| {
+            init_late_loggers(tcx);
+            if !tcx.sess.crate_types().contains(&CrateType::Executable) {
+                tcx.sess.fatal("miri only makes sense on bin crates");
+            }
+
+            let (entry_def_id, entry_type) = if let Some(entry_def) = tcx.entry_fn(()) {
+                entry_def
+            } else {
+                tcx.sess.fatal("miri can only run programs that have a main function");
+            };
+            let mut config = self.miri_config.clone();
+
+            // Add filename to `miri` arguments.
+            config.args.insert(0, compiler.input().filestem().to_string());
+
+            // Adjust working directory for interpretation.
+            if let Some(cwd) = env::var_os("MIRI_CWD") {
+                env::set_current_dir(cwd).unwrap();
+            }
+
+            if let Some(return_code) = miri::eval_entry(tcx, entry_def_id, entry_type, config) {
+                std::process::exit(
+                    i32::try_from(return_code).expect("Return value was too large!"),
+                );
+            }
+        });
+
+        compiler.session().abort_if_errors();
+
+        Compilation::Stop
+    }
+}
+
+struct MiriBeRustCompilerCalls {
+    target_crate: bool,
+}
+
+impl rustc_driver::Callbacks for MiriBeRustCompilerCalls {
+    #[allow(rustc::potential_query_instability)] // rustc_codegen_ssa (where this code is copied from) also allows this lint
+    fn config(&mut self, config: &mut Config) {
+        if config.opts.prints.is_empty() && self.target_crate {
+            // Queries overriden here affect the data stored in `rmeta` files of dependencies,
+            // which will be used later in non-`MIRI_BE_RUSTC` mode.
+            config.override_queries = Some(|_, local_providers, _| {
+                // `exported_symbols` and `reachable_non_generics` provided by rustc always returns
+                // an empty result if `tcx.sess.opts.output_types.should_codegen()` is false.
+                local_providers.exported_symbols = |tcx, cnum| {
+                    assert_eq!(cnum, LOCAL_CRATE);
+                    tcx.arena.alloc_from_iter(
+                        // This is based on:
+                        // https://github.com/rust-lang/rust/blob/2962e7c0089d5c136f4e9600b7abccfbbde4973d/compiler/rustc_codegen_ssa/src/back/symbol_export.rs#L62-L63
+                        // https://github.com/rust-lang/rust/blob/2962e7c0089d5c136f4e9600b7abccfbbde4973d/compiler/rustc_codegen_ssa/src/back/symbol_export.rs#L174
+                        tcx.reachable_set(()).iter().filter_map(|&local_def_id| {
+                            // Do the same filtering that rustc does:
+                            // https://github.com/rust-lang/rust/blob/2962e7c0089d5c136f4e9600b7abccfbbde4973d/compiler/rustc_codegen_ssa/src/back/symbol_export.rs#L84-L102
+                            // Otherwise it may cause unexpected behaviours and ICEs
+                            // (https://github.com/rust-lang/rust/issues/86261).
+                            let is_reachable_non_generic = matches!(
+                                tcx.hir().get(tcx.hir().local_def_id_to_hir_id(local_def_id)),
+                                Node::Item(&hir::Item {
+                                    kind: hir::ItemKind::Static(..) | hir::ItemKind::Fn(..),
+                                    ..
+                                }) | Node::ImplItem(&hir::ImplItem {
+                                    kind: hir::ImplItemKind::Fn(..),
+                                    ..
+                                })
+                                if !tcx.generics_of(local_def_id).requires_monomorphization(tcx)
+                            );
+                            (is_reachable_non_generic
+                                && tcx.codegen_fn_attrs(local_def_id).contains_extern_indicator())
+                            .then_some((
+                                ExportedSymbol::NonGeneric(local_def_id.to_def_id()),
+                                // Some dummy `SymbolExportInfo` here. We only use
+                                // `exported_symbols` in shims/foreign_items.rs and the export info
+                                // is ignored.
+                                SymbolExportInfo {
+                                    level: SymbolExportLevel::C,
+                                    kind: SymbolExportKind::Text,
+                                    used: false,
+                                },
+                            ))
+                        }),
+                    )
+                }
+            });
+        }
+    }
+}
+
+fn show_error(msg: &impl std::fmt::Display) -> ! {
+    eprintln!("fatal error: {msg}");
+    std::process::exit(1)
+}
+
+macro_rules! show_error {
+    ($($tt:tt)*) => { show_error(&format_args!($($tt)*)) };
+}
+
+fn init_early_loggers() {
+    // Note that our `extern crate log` is *not* the same as rustc's; as a result, we have to
+    // initialize them both, and we always initialize `miri`'s first.
+    let env = env_logger::Env::new().filter("MIRI_LOG").write_style("MIRI_LOG_STYLE");
+    env_logger::init_from_env(env);
+    // Enable verbose entry/exit logging by default if MIRI_LOG is set.
+    if env::var_os("MIRI_LOG").is_some() && env::var_os("RUSTC_LOG_ENTRY_EXIT").is_none() {
+        env::set_var("RUSTC_LOG_ENTRY_EXIT", "1");
+    }
+    // We only initialize `rustc` if the env var is set (so the user asked for it).
+    // If it is not set, we avoid initializing now so that we can initialize
+    // later with our custom settings, and *not* log anything for what happens before
+    // `miri` gets started.
+    if env::var_os("RUSTC_LOG").is_some() {
+        rustc_driver::init_rustc_env_logger();
+    }
+}
+
+fn init_late_loggers(tcx: TyCtxt<'_>) {
+    // We initialize loggers right before we start evaluation. We overwrite the `RUSTC_LOG`
+    // env var if it is not set, control it based on `MIRI_LOG`.
+    // (FIXME: use `var_os`, but then we need to manually concatenate instead of `format!`.)
+    if let Ok(var) = env::var("MIRI_LOG") {
+        if env::var_os("RUSTC_LOG").is_none() {
+            // We try to be a bit clever here: if `MIRI_LOG` is just a single level
+            // used for everything, we only apply it to the parts of rustc that are
+            // CTFE-related. Otherwise, we use it verbatim for `RUSTC_LOG`.
+            // This way, if you set `MIRI_LOG=trace`, you get only the right parts of
+            // rustc traced, but you can also do `MIRI_LOG=miri=trace,rustc_const_eval::interpret=debug`.
+            if log::Level::from_str(&var).is_ok() {
+                env::set_var(
+                    "RUSTC_LOG",
+                    &format!(
+                        "rustc_middle::mir::interpret={0},rustc_const_eval::interpret={0}",
+                        var
+                    ),
+                );
+            } else {
+                env::set_var("RUSTC_LOG", &var);
+            }
+            rustc_driver::init_rustc_env_logger();
+        }
+    }
+
+    // If `MIRI_BACKTRACE` is set and `RUSTC_CTFE_BACKTRACE` is not, set `RUSTC_CTFE_BACKTRACE`.
+    // Do this late, so we ideally only apply this to Miri's errors.
+    if let Some(val) = env::var_os("MIRI_BACKTRACE") {
+        let ctfe_backtrace = match &*val.to_string_lossy() {
+            "immediate" => CtfeBacktrace::Immediate,
+            "0" => CtfeBacktrace::Disabled,
+            _ => CtfeBacktrace::Capture,
+        };
+        *tcx.sess.ctfe_backtrace.borrow_mut() = ctfe_backtrace;
+    }
+}
+
+/// Returns the "default sysroot" that Miri will use for host things if no `--sysroot` flag is set.
+/// Should be a compile-time constant.
+fn host_sysroot() -> Option<String> {
+    if option_env!("RUSTC_STAGE").is_some() {
+        // This is being built as part of rustc, and gets shipped with rustup.
+        // We can rely on the sysroot computation in librustc_session.
+        return None;
+    }
+    // For builds outside rustc, we need to ensure that we got a sysroot
+    // that gets used as a default.  The sysroot computation in librustc_session would
+    // end up somewhere in the build dir (see `get_or_default_sysroot`).
+    // Taken from PR <https://github.com/Manishearth/rust-clippy/pull/911>.
+    let home = option_env!("RUSTUP_HOME").or(option_env!("MULTIRUST_HOME"));
+    let toolchain = option_env!("RUSTUP_TOOLCHAIN").or(option_env!("MULTIRUST_TOOLCHAIN"));
+    Some(match (home, toolchain) {
+        (Some(home), Some(toolchain)) => {
+            // Check that at runtime, we are still in this toolchain (if there is any toolchain).
+            if let Some(toolchain_runtime) =
+                env::var_os("RUSTUP_TOOLCHAIN").or_else(|| env::var_os("MULTIRUST_TOOLCHAIN"))
+            {
+                if toolchain_runtime != toolchain {
+                    show_error!(
+                        "This Miri got built with local toolchain `{toolchain}`, but now is being run under a different toolchain. \n\
+                        Make sure to run Miri in the toolchain it got built with, e.g. via `cargo +{toolchain} miri`."
+                    )
+                }
+            }
+            format!("{}/toolchains/{}", home, toolchain)
+        }
+        _ => option_env!("RUST_SYSROOT")
+            .unwrap_or_else(|| {
+                show_error!(
+                    "To build Miri without rustup, set the `RUST_SYSROOT` env var at build time",
+                )
+            })
+            .to_owned(),
+    })
+}
+
+/// Execute a compiler with the given CLI arguments and callbacks.
+fn run_compiler(
+    mut args: Vec<String>,
+    target_crate: bool,
+    callbacks: &mut (dyn rustc_driver::Callbacks + Send),
+) -> ! {
+    // Make sure we use the right default sysroot. The default sysroot is wrong,
+    // because `get_or_default_sysroot` in `librustc_session` bases that on `current_exe`.
+    //
+    // Make sure we always call `host_sysroot` as that also does some sanity-checks
+    // of the environment we were built in and whether it matches what we are running in.
+    let host_default_sysroot = host_sysroot();
+    // Now see if we even need to set something.
+    let sysroot_flag = "--sysroot";
+    if !args.iter().any(|e| e == sysroot_flag) {
+        // No sysroot was set, let's see if we have a custom default we want to configure.
+        let default_sysroot = if target_crate {
+            // Using the built-in default here would be plain wrong, so we *require*
+            // the env var to make sure things make sense.
+            Some(env::var("MIRI_SYSROOT").unwrap_or_else(|_| {
+                show_error!(
+                    "Miri was invoked in 'target' mode without `MIRI_SYSROOT` or `--sysroot` being set"
+                )
+            }))
+        } else {
+            host_default_sysroot
+        };
+        if let Some(sysroot) = default_sysroot {
+            // We need to overwrite the default that librustc_session would compute.
+            args.push(sysroot_flag.to_owned());
+            args.push(sysroot);
+        }
+    }
+
+    // Don't insert `MIRI_DEFAULT_ARGS`, in particular, `--cfg=miri`, if we are building
+    // a "host" crate. That may cause procedural macros (and probably build scripts) to
+    // depend on Miri-only symbols, such as `miri_resolve_frame`:
+    // https://github.com/rust-lang/miri/issues/1760
+    if target_crate {
+        // Some options have different defaults in Miri than in plain rustc; apply those by making
+        // them the first arguments after the binary name (but later arguments can overwrite them).
+        args.splice(1..1, miri::MIRI_DEFAULT_ARGS.iter().map(ToString::to_string));
+    }
+
+    // Invoke compiler, and handle return code.
+    let exit_code = rustc_driver::catch_with_exit_code(move || {
+        rustc_driver::RunCompiler::new(&args, callbacks).run()
+    });
+    std::process::exit(exit_code)
+}
+
+/// Parses a comma separated list of `T` from the given string:
+///
+/// `<value1>,<value2>,<value3>,...`
+fn parse_comma_list<T: FromStr>(input: &str) -> Result<Vec<T>, T::Err> {
+    input.split(',').map(str::parse::<T>).collect()
+}
+
+fn main() {
+    // Snapshot a copy of the environment before `rustc` starts messing with it.
+    // (`install_ice_hook` might change `RUST_BACKTRACE`.)
+    let env_snapshot = env::vars_os().collect::<Vec<_>>();
+
+    // Earliest rustc setup.
+    rustc_driver::install_ice_hook();
+
+    // If the environment asks us to actually be rustc, then do that.
+    if let Some(crate_kind) = env::var_os("MIRI_BE_RUSTC") {
+        rustc_driver::init_rustc_env_logger();
+
+        let target_crate = if crate_kind == "target" {
+            true
+        } else if crate_kind == "host" {
+            false
+        } else {
+            panic!("invalid `MIRI_BE_RUSTC` value: {:?}", crate_kind)
+        };
+
+        // We cannot use `rustc_driver::main` as we need to adjust the CLI arguments.
+        run_compiler(
+            env::args().collect(),
+            target_crate,
+            &mut MiriBeRustCompilerCalls { target_crate },
+        )
+    }
+
+    // Init loggers the Miri way.
+    init_early_loggers();
+
+    // Parse our arguments and split them across `rustc` and `miri`.
+    let mut miri_config = miri::MiriConfig::default();
+    miri_config.env = env_snapshot;
+
+    let mut rustc_args = vec![];
+    let mut after_dashdash = false;
+
+    // If user has explicitly enabled/disabled isolation
+    let mut isolation_enabled: Option<bool> = None;
+    for arg in env::args() {
+        if rustc_args.is_empty() {
+            // Very first arg: binary name.
+            rustc_args.push(arg);
+        } else if after_dashdash {
+            // Everything that comes after `--` is forwarded to the interpreted crate.
+            miri_config.args.push(arg);
+        } else if arg == "--" {
+            after_dashdash = true;
+        } else if arg == "-Zmiri-disable-validation" {
+            miri_config.validate = false;
+        } else if arg == "-Zmiri-disable-stacked-borrows" {
+            miri_config.stacked_borrows = false;
+        } else if arg == "-Zmiri-disable-data-race-detector" {
+            miri_config.data_race_detector = false;
+            miri_config.weak_memory_emulation = false;
+        } else if arg == "-Zmiri-disable-alignment-check" {
+            miri_config.check_alignment = miri::AlignmentCheck::None;
+        } else if arg == "-Zmiri-symbolic-alignment-check" {
+            miri_config.check_alignment = miri::AlignmentCheck::Symbolic;
+        } else if arg == "-Zmiri-check-number-validity" {
+            eprintln!(
+                "WARNING: the flag `-Zmiri-check-number-validity` no longer has any effect \
+                        since it is now enabled by default"
+            );
+        } else if arg == "-Zmiri-disable-abi-check" {
+            miri_config.check_abi = false;
+        } else if arg == "-Zmiri-disable-isolation" {
+            if matches!(isolation_enabled, Some(true)) {
+                show_error!(
+                    "-Zmiri-disable-isolation cannot be used along with -Zmiri-isolation-error"
+                );
+            } else {
+                isolation_enabled = Some(false);
+            }
+            miri_config.isolated_op = miri::IsolatedOp::Allow;
+        } else if arg == "-Zmiri-disable-weak-memory-emulation" {
+            miri_config.weak_memory_emulation = false;
+        } else if arg == "-Zmiri-track-weak-memory-loads" {
+            miri_config.track_outdated_loads = true;
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-isolation-error=") {
+            if matches!(isolation_enabled, Some(false)) {
+                show_error!(
+                    "-Zmiri-isolation-error cannot be used along with -Zmiri-disable-isolation"
+                );
+            } else {
+                isolation_enabled = Some(true);
+            }
+
+            miri_config.isolated_op = match param {
+                "abort" => miri::IsolatedOp::Reject(miri::RejectOpWith::Abort),
+                "hide" => miri::IsolatedOp::Reject(miri::RejectOpWith::NoWarning),
+                "warn" => miri::IsolatedOp::Reject(miri::RejectOpWith::Warning),
+                "warn-nobacktrace" =>
+                    miri::IsolatedOp::Reject(miri::RejectOpWith::WarningWithoutBacktrace),
+                _ =>
+                    show_error!(
+                        "-Zmiri-isolation-error must be `abort`, `hide`, `warn`, or `warn-nobacktrace`"
+                    ),
+            };
+        } else if arg == "-Zmiri-ignore-leaks" {
+            miri_config.ignore_leaks = true;
+        } else if arg == "-Zmiri-panic-on-unsupported" {
+            miri_config.panic_on_unsupported = true;
+        } else if arg == "-Zmiri-tag-raw-pointers" {
+            eprintln!("WARNING: `-Zmiri-tag-raw-pointers` has no effect; it is enabled by default");
+        } else if arg == "-Zmiri-strict-provenance" {
+            miri_config.provenance_mode = ProvenanceMode::Strict;
+        } else if arg == "-Zmiri-permissive-provenance" {
+            miri_config.provenance_mode = ProvenanceMode::Permissive;
+        } else if arg == "-Zmiri-mute-stdout-stderr" {
+            miri_config.mute_stdout_stderr = true;
+        } else if arg == "-Zmiri-retag-fields" {
+            miri_config.retag_fields = true;
+        } else if arg == "-Zmiri-track-raw-pointers" {
+            eprintln!(
+                "WARNING: `-Zmiri-track-raw-pointers` has no effect; it is enabled by default"
+            );
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-seed=") {
+            if miri_config.seed.is_some() {
+                show_error!("Cannot specify -Zmiri-seed multiple times!");
+            }
+            let seed = u64::from_str_radix(param, 16)
+                        .unwrap_or_else(|_| show_error!(
+                            "-Zmiri-seed should only contain valid hex digits [0-9a-fA-F] and must fit into a u64 (max 16 characters)"
+                        ));
+            miri_config.seed = Some(seed);
+        } else if let Some(_param) = arg.strip_prefix("-Zmiri-env-exclude=") {
+            show_error!(
+                "`-Zmiri-env-exclude` has been removed; unset env vars before starting Miri instead"
+            );
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-env-forward=") {
+            miri_config.forwarded_env_vars.push(param.to_owned());
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-track-pointer-tag=") {
+            let ids: Vec<u64> = match parse_comma_list(param) {
+                Ok(ids) => ids,
+                Err(err) =>
+                    show_error!(
+                        "-Zmiri-track-pointer-tag requires a comma separated list of valid `u64` arguments: {}",
+                        err
+                    ),
+            };
+            for id in ids.into_iter().map(miri::SbTag::new) {
+                if let Some(id) = id {
+                    miri_config.tracked_pointer_tags.insert(id);
+                } else {
+                    show_error!("-Zmiri-track-pointer-tag requires nonzero arguments");
+                }
+            }
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-track-call-id=") {
+            let ids: Vec<u64> = match parse_comma_list(param) {
+                Ok(ids) => ids,
+                Err(err) =>
+                    show_error!(
+                        "-Zmiri-track-call-id requires a comma separated list of valid `u64` arguments: {}",
+                        err
+                    ),
+            };
+            for id in ids.into_iter().map(miri::CallId::new) {
+                if let Some(id) = id {
+                    miri_config.tracked_call_ids.insert(id);
+                } else {
+                    show_error!("-Zmiri-track-call-id requires a nonzero argument");
+                }
+            }
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-track-alloc-id=") {
+            let ids: Vec<miri::AllocId> = match parse_comma_list::<NonZeroU64>(param) {
+                Ok(ids) => ids.into_iter().map(miri::AllocId).collect(),
+                Err(err) =>
+                    show_error!(
+                        "-Zmiri-track-alloc-id requires a comma separated list of valid non-zero `u64` arguments: {}",
+                        err
+                    ),
+            };
+            miri_config.tracked_alloc_ids.extend(ids);
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-compare-exchange-weak-failure-rate=") {
+            let rate = match param.parse::<f64>() {
+                Ok(rate) if rate >= 0.0 && rate <= 1.0 => rate,
+                Ok(_) =>
+                    show_error!(
+                        "-Zmiri-compare-exchange-weak-failure-rate must be between `0.0` and `1.0`"
+                    ),
+                Err(err) =>
+                    show_error!(
+                        "-Zmiri-compare-exchange-weak-failure-rate requires a `f64` between `0.0` and `1.0`: {}",
+                        err
+                    ),
+            };
+            miri_config.cmpxchg_weak_failure_rate = rate;
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-preemption-rate=") {
+            let rate = match param.parse::<f64>() {
+                Ok(rate) if rate >= 0.0 && rate <= 1.0 => rate,
+                Ok(_) => show_error!("-Zmiri-preemption-rate must be between `0.0` and `1.0`"),
+                Err(err) =>
+                    show_error!(
+                        "-Zmiri-preemption-rate requires a `f64` between `0.0` and `1.0`: {}",
+                        err
+                    ),
+            };
+            miri_config.preemption_rate = rate;
+        } else if arg == "-Zmiri-report-progress" {
+            // This makes it take a few seconds between progress reports on my laptop.
+            miri_config.report_progress = Some(1_000_000);
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-report-progress=") {
+            let interval = match param.parse::<u32>() {
+                Ok(i) => i,
+                Err(err) => show_error!("-Zmiri-report-progress requires a `u32`: {}", err),
+            };
+            miri_config.report_progress = Some(interval);
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-tag-gc=") {
+            let interval = match param.parse::<u32>() {
+                Ok(i) => i,
+                Err(err) => show_error!("-Zmiri-tag-gc requires a `u32`: {}", err),
+            };
+            miri_config.gc_interval = interval;
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-measureme=") {
+            miri_config.measureme_out = Some(param.to_string());
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-backtrace=") {
+            miri_config.backtrace_style = match param {
+                "0" => BacktraceStyle::Off,
+                "1" => BacktraceStyle::Short,
+                "full" => BacktraceStyle::Full,
+                _ => show_error!("-Zmiri-backtrace may only be 0, 1, or full"),
+            };
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-extern-so-file=") {
+            let filename = param.to_string();
+            if std::path::Path::new(&filename).exists() {
+                if let Some(other_filename) = miri_config.external_so_file {
+                    show_error!(
+                        "-Zmiri-extern-so-file is already set to {}",
+                        other_filename.display()
+                    );
+                }
+                miri_config.external_so_file = Some(filename.into());
+            } else {
+                show_error!("-Zmiri-extern-so-file `{}` does not exist", filename);
+            }
+        } else {
+            // Forward to rustc.
+            rustc_args.push(arg);
+        }
+    }
+
+    debug!("rustc arguments: {:?}", rustc_args);
+    debug!("crate arguments: {:?}", miri_config.args);
+    run_compiler(rustc_args, /* target_crate: */ true, &mut MiriCompilerCalls { miri_config })
+}
diff --git a/src/tools/miri/src/clock.rs b/src/tools/miri/src/clock.rs
new file mode 100644
index 000000000000..3f33273e1e54
--- /dev/null
+++ b/src/tools/miri/src/clock.rs
@@ -0,0 +1,115 @@
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::time::{Duration, Instant as StdInstant};
+
+/// When using a virtual clock, this defines how many nanoseconds we pretend are passing for each
+/// basic block.
+const NANOSECONDS_PER_BASIC_BLOCK: u64 = 10;
+
+#[derive(Debug)]
+pub struct Instant {
+    kind: InstantKind,
+}
+
+#[derive(Debug)]
+enum InstantKind {
+    Host(StdInstant),
+    Virtual { nanoseconds: u64 },
+}
+
+impl Instant {
+    pub fn checked_add(&self, duration: Duration) -> Option<Instant> {
+        match self.kind {
+            InstantKind::Host(instant) =>
+                instant.checked_add(duration).map(|i| Instant { kind: InstantKind::Host(i) }),
+            InstantKind::Virtual { nanoseconds } =>
+                u128::from(nanoseconds)
+                    .checked_add(duration.as_nanos())
+                    .and_then(|n| u64::try_from(n).ok())
+                    .map(|nanoseconds| Instant { kind: InstantKind::Virtual { nanoseconds } }),
+        }
+    }
+
+    pub fn duration_since(&self, earlier: Instant) -> Duration {
+        match (&self.kind, earlier.kind) {
+            (InstantKind::Host(instant), InstantKind::Host(earlier)) =>
+                instant.duration_since(earlier),
+            (
+                InstantKind::Virtual { nanoseconds },
+                InstantKind::Virtual { nanoseconds: earlier },
+            ) => Duration::from_nanos(nanoseconds.saturating_sub(earlier)),
+            _ => panic!("all `Instant` must be of the same kind"),
+        }
+    }
+}
+
+/// A monotone clock used for `Instant` simulation.
+#[derive(Debug)]
+pub struct Clock {
+    kind: ClockKind,
+}
+
+#[derive(Debug)]
+enum ClockKind {
+    Host {
+        /// The "time anchor" for this machine's monotone clock.
+        time_anchor: StdInstant,
+    },
+    Virtual {
+        /// The "current virtual time".
+        nanoseconds: AtomicU64,
+    },
+}
+
+impl Clock {
+    /// Create a new clock based on the availability of communication with the host.
+    pub fn new(communicate: bool) -> Self {
+        let kind = if communicate {
+            ClockKind::Host { time_anchor: StdInstant::now() }
+        } else {
+            ClockKind::Virtual { nanoseconds: 0.into() }
+        };
+
+        Self { kind }
+    }
+
+    /// Let the time pass for a small interval.
+    pub fn tick(&self) {
+        match &self.kind {
+            ClockKind::Host { .. } => {
+                // Time will pass without us doing anything.
+            }
+            ClockKind::Virtual { nanoseconds } => {
+                nanoseconds.fetch_add(NANOSECONDS_PER_BASIC_BLOCK, Ordering::SeqCst);
+            }
+        }
+    }
+
+    /// Sleep for the desired duration.
+    pub fn sleep(&self, duration: Duration) {
+        match &self.kind {
+            ClockKind::Host { .. } => std::thread::sleep(duration),
+            ClockKind::Virtual { nanoseconds } => {
+                // Just pretend that we have slept for some time.
+                nanoseconds.fetch_add(duration.as_nanos().try_into().unwrap(), Ordering::SeqCst);
+            }
+        }
+    }
+
+    /// Return the `anchor` instant, to convert between monotone instants and durations relative to the anchor.
+    pub fn anchor(&self) -> Instant {
+        match &self.kind {
+            ClockKind::Host { time_anchor } => Instant { kind: InstantKind::Host(*time_anchor) },
+            ClockKind::Virtual { .. } => Instant { kind: InstantKind::Virtual { nanoseconds: 0 } },
+        }
+    }
+
+    pub fn now(&self) -> Instant {
+        match &self.kind {
+            ClockKind::Host { .. } => Instant { kind: InstantKind::Host(StdInstant::now()) },
+            ClockKind::Virtual { nanoseconds } =>
+                Instant {
+                    kind: InstantKind::Virtual { nanoseconds: nanoseconds.load(Ordering::SeqCst) },
+                },
+        }
+    }
+}
diff --git a/src/tools/miri/src/concurrency/data_race.rs b/src/tools/miri/src/concurrency/data_race.rs
new file mode 100644
index 000000000000..2e54ddaaba11
--- /dev/null
+++ b/src/tools/miri/src/concurrency/data_race.rs
@@ -0,0 +1,1596 @@
+//! Implementation of a data-race detector using Lamport Timestamps / Vector-clocks
+//! based on the Dynamic Race Detection for C++:
+//! <https://www.doc.ic.ac.uk/~afd/homepages/papers/pdfs/2017/POPL.pdf>
+//! which does not report false-positives when fences are used, and gives better
+//! accuracy in presence of read-modify-write operations.
+//!
+//! The implementation contains modifications to correctly model the changes to the memory model in C++20
+//! regarding the weakening of release sequences: <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0982r1.html>.
+//! Relaxed stores now unconditionally block all currently active release sequences and so per-thread tracking of release
+//! sequences is not needed.
+//!
+//! The implementation also models races with memory allocation and deallocation via treating allocation and
+//! deallocation as a type of write internally for detecting data-races.
+//!
+//! Weak memory orders are explored but not all weak behaviours are exhibited, so it can still miss data-races
+//! but should not report false-positives
+//!
+//! Data-race definition from(<https://en.cppreference.com/w/cpp/language/memory_model#Threads_and_data_races>):
+//! a data race occurs between two memory accesses if they are on different threads, at least one operation
+//! is non-atomic, at least one operation is a write and neither access happens-before the other. Read the link
+//! for full definition.
+//!
+//! This re-uses vector indexes for threads that are known to be unable to report data-races, this is valid
+//! because it only re-uses vector indexes once all currently-active (not-terminated) threads have an internal
+//! vector clock that happens-after the join operation of the candidate thread. Threads that have not been joined
+//! on are not considered. Since the thread's vector clock will only increase and a data-race implies that
+//! there is some index x where `clock[x] > thread_clock`, when this is true `clock[candidate-idx] > thread_clock`
+//! can never hold and hence a data-race can never be reported in that vector index again.
+//! This means that the thread-index can be safely re-used, starting on the next timestamp for the newly created
+//! thread.
+//!
+//! The timestamps used in the data-race detector assign each sequence of non-atomic operations
+//! followed by a single atomic or concurrent operation a single timestamp.
+//! Write, Read, Write, ThreadJoin will be represented by a single timestamp value on a thread.
+//! This is because extra increment operations between the operations in the sequence are not
+//! required for accurate reporting of data-race values.
+//!
+//! As per the paper a threads timestamp is only incremented after a release operation is performed
+//! so some atomic operations that only perform acquires do not increment the timestamp. Due to shared
+//! code some atomic operations may increment the timestamp when not necessary but this has no effect
+//! on the data-race detection code.
+
+use std::{
+    cell::{Cell, Ref, RefCell, RefMut},
+    fmt::Debug,
+    mem,
+};
+
+use rustc_ast::Mutability;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_index::vec::{Idx, IndexVec};
+use rustc_middle::{mir, ty::layout::TyAndLayout};
+use rustc_target::abi::{Align, Size};
+
+use crate::*;
+
+use super::{
+    vector_clock::{VClock, VTimestamp, VectorIdx},
+    weak_memory::EvalContextExt as _,
+};
+
+pub type AllocExtra = VClockAlloc;
+
+/// Valid atomic read-write orderings, alias of atomic::Ordering (not non-exhaustive).
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum AtomicRwOrd {
+    Relaxed,
+    Acquire,
+    Release,
+    AcqRel,
+    SeqCst,
+}
+
+/// Valid atomic read orderings, subset of atomic::Ordering.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum AtomicReadOrd {
+    Relaxed,
+    Acquire,
+    SeqCst,
+}
+
+/// Valid atomic write orderings, subset of atomic::Ordering.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum AtomicWriteOrd {
+    Relaxed,
+    Release,
+    SeqCst,
+}
+
+/// Valid atomic fence orderings, subset of atomic::Ordering.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum AtomicFenceOrd {
+    Acquire,
+    Release,
+    AcqRel,
+    SeqCst,
+}
+
+/// The current set of vector clocks describing the state
+/// of a thread, contains the happens-before clock and
+/// additional metadata to model atomic fence operations.
+#[derive(Clone, Default, Debug)]
+pub(super) struct ThreadClockSet {
+    /// The increasing clock representing timestamps
+    /// that happen-before this thread.
+    pub(super) clock: VClock,
+
+    /// The set of timestamps that will happen-before this
+    /// thread once it performs an acquire fence.
+    fence_acquire: VClock,
+
+    /// The last timestamp of happens-before relations that
+    /// have been released by this thread by a fence.
+    fence_release: VClock,
+
+    /// Timestamps of the last SC fence performed by each
+    /// thread, updated when this thread performs an SC fence
+    pub(super) fence_seqcst: VClock,
+
+    /// Timestamps of the last SC write performed by each
+    /// thread, updated when this thread performs an SC fence
+    pub(super) write_seqcst: VClock,
+
+    /// Timestamps of the last SC fence performed by each
+    /// thread, updated when this thread performs an SC read
+    pub(super) read_seqcst: VClock,
+}
+
+impl ThreadClockSet {
+    /// Apply the effects of a release fence to this
+    /// set of thread vector clocks.
+    #[inline]
+    fn apply_release_fence(&mut self) {
+        self.fence_release.clone_from(&self.clock);
+    }
+
+    /// Apply the effects of an acquire fence to this
+    /// set of thread vector clocks.
+    #[inline]
+    fn apply_acquire_fence(&mut self) {
+        self.clock.join(&self.fence_acquire);
+    }
+
+    /// Increment the happens-before clock at a
+    /// known index.
+    #[inline]
+    fn increment_clock(&mut self, index: VectorIdx) {
+        self.clock.increment_index(index);
+    }
+
+    /// Join the happens-before clock with that of
+    /// another thread, used to model thread join
+    /// operations.
+    fn join_with(&mut self, other: &ThreadClockSet) {
+        self.clock.join(&other.clock);
+    }
+}
+
+/// Error returned by finding a data race
+/// should be elaborated upon.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+pub struct DataRace;
+
+/// Externally stored memory cell clocks
+/// explicitly to reduce memory usage for the
+/// common case where no atomic operations
+/// exists on the memory cell.
+#[derive(Clone, PartialEq, Eq, Default, Debug)]
+struct AtomicMemoryCellClocks {
+    /// The clock-vector of the timestamp of the last atomic
+    /// read operation performed by each thread.
+    /// This detects potential data-races between atomic read
+    /// and non-atomic write operations.
+    read_vector: VClock,
+
+    /// The clock-vector of the timestamp of the last atomic
+    /// write operation performed by each thread.
+    /// This detects potential data-races between atomic write
+    /// and non-atomic read or write operations.
+    write_vector: VClock,
+
+    /// Synchronization vector for acquire-release semantics
+    /// contains the vector of timestamps that will
+    /// happen-before a thread if an acquire-load is
+    /// performed on the data.
+    sync_vector: VClock,
+}
+
+/// Type of write operation: allocating memory
+/// non-atomic writes and deallocating memory
+/// are all treated as writes for the purpose
+/// of the data-race detector.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+enum WriteType {
+    /// Allocate memory.
+    Allocate,
+
+    /// Standard unsynchronized write.
+    Write,
+
+    /// Deallocate memory.
+    /// Note that when memory is deallocated first, later non-atomic accesses
+    /// will be reported as use-after-free, not as data races.
+    /// (Same for `Allocate` above.)
+    Deallocate,
+}
+impl WriteType {
+    fn get_descriptor(self) -> &'static str {
+        match self {
+            WriteType::Allocate => "Allocate",
+            WriteType::Write => "Write",
+            WriteType::Deallocate => "Deallocate",
+        }
+    }
+}
+
+/// Memory Cell vector clock metadata
+/// for data-race detection.
+#[derive(Clone, PartialEq, Eq, Debug)]
+struct MemoryCellClocks {
+    /// The vector-clock timestamp of the last write
+    /// corresponding to the writing threads timestamp.
+    write: VTimestamp,
+
+    /// The identifier of the vector index, corresponding to a thread
+    /// that performed the last write operation.
+    write_index: VectorIdx,
+
+    /// The type of operation that the write index represents,
+    /// either newly allocated memory, a non-atomic write or
+    /// a deallocation of memory.
+    write_type: WriteType,
+
+    /// The vector-clock of the timestamp of the last read operation
+    /// performed by a thread since the last write operation occurred.
+    /// It is reset to zero on each write operation.
+    read: VClock,
+
+    /// Atomic acquire & release sequence tracking clocks.
+    /// For non-atomic memory in the common case this
+    /// value is set to None.
+    atomic_ops: Option<Box<AtomicMemoryCellClocks>>,
+}
+
+impl MemoryCellClocks {
+    /// Create a new set of clocks representing memory allocated
+    ///  at a given vector timestamp and index.
+    fn new(alloc: VTimestamp, alloc_index: VectorIdx) -> Self {
+        MemoryCellClocks {
+            read: VClock::default(),
+            write: alloc,
+            write_index: alloc_index,
+            write_type: WriteType::Allocate,
+            atomic_ops: None,
+        }
+    }
+
+    /// Load the internal atomic memory cells if they exist.
+    #[inline]
+    fn atomic(&self) -> Option<&AtomicMemoryCellClocks> {
+        self.atomic_ops.as_deref()
+    }
+
+    /// Load or create the internal atomic memory metadata
+    /// if it does not exist.
+    #[inline]
+    fn atomic_mut(&mut self) -> &mut AtomicMemoryCellClocks {
+        self.atomic_ops.get_or_insert_with(Default::default)
+    }
+
+    /// Update memory cell data-race tracking for atomic
+    /// load acquire semantics, is a no-op if this memory was
+    /// not used previously as atomic memory.
+    fn load_acquire(
+        &mut self,
+        clocks: &mut ThreadClockSet,
+        index: VectorIdx,
+    ) -> Result<(), DataRace> {
+        self.atomic_read_detect(clocks, index)?;
+        if let Some(atomic) = self.atomic() {
+            clocks.clock.join(&atomic.sync_vector);
+        }
+        Ok(())
+    }
+
+    /// Checks if the memory cell access is ordered with all prior atomic reads and writes
+    fn race_free_with_atomic(&self, clocks: &ThreadClockSet) -> bool {
+        if let Some(atomic) = self.atomic() {
+            atomic.read_vector <= clocks.clock && atomic.write_vector <= clocks.clock
+        } else {
+            true
+        }
+    }
+
+    /// Update memory cell data-race tracking for atomic
+    /// load relaxed semantics, is a no-op if this memory was
+    /// not used previously as atomic memory.
+    fn load_relaxed(
+        &mut self,
+        clocks: &mut ThreadClockSet,
+        index: VectorIdx,
+    ) -> Result<(), DataRace> {
+        self.atomic_read_detect(clocks, index)?;
+        if let Some(atomic) = self.atomic() {
+            clocks.fence_acquire.join(&atomic.sync_vector);
+        }
+        Ok(())
+    }
+
+    /// Update the memory cell data-race tracking for atomic
+    /// store release semantics.
+    fn store_release(&mut self, clocks: &ThreadClockSet, index: VectorIdx) -> Result<(), DataRace> {
+        self.atomic_write_detect(clocks, index)?;
+        let atomic = self.atomic_mut();
+        atomic.sync_vector.clone_from(&clocks.clock);
+        Ok(())
+    }
+
+    /// Update the memory cell data-race tracking for atomic
+    /// store relaxed semantics.
+    fn store_relaxed(&mut self, clocks: &ThreadClockSet, index: VectorIdx) -> Result<(), DataRace> {
+        self.atomic_write_detect(clocks, index)?;
+
+        // The handling of release sequences was changed in C++20 and so
+        // the code here is different to the paper since now all relaxed
+        // stores block release sequences. The exception for same-thread
+        // relaxed stores has been removed.
+        let atomic = self.atomic_mut();
+        atomic.sync_vector.clone_from(&clocks.fence_release);
+        Ok(())
+    }
+
+    /// Update the memory cell data-race tracking for atomic
+    /// store release semantics for RMW operations.
+    fn rmw_release(&mut self, clocks: &ThreadClockSet, index: VectorIdx) -> Result<(), DataRace> {
+        self.atomic_write_detect(clocks, index)?;
+        let atomic = self.atomic_mut();
+        atomic.sync_vector.join(&clocks.clock);
+        Ok(())
+    }
+
+    /// Update the memory cell data-race tracking for atomic
+    /// store relaxed semantics for RMW operations.
+    fn rmw_relaxed(&mut self, clocks: &ThreadClockSet, index: VectorIdx) -> Result<(), DataRace> {
+        self.atomic_write_detect(clocks, index)?;
+        let atomic = self.atomic_mut();
+        atomic.sync_vector.join(&clocks.fence_release);
+        Ok(())
+    }
+
+    /// Detect data-races with an atomic read, caused by a non-atomic write that does
+    /// not happen-before the atomic-read.
+    fn atomic_read_detect(
+        &mut self,
+        clocks: &ThreadClockSet,
+        index: VectorIdx,
+    ) -> Result<(), DataRace> {
+        log::trace!("Atomic read with vectors: {:#?} :: {:#?}", self, clocks);
+        if self.write <= clocks.clock[self.write_index] {
+            let atomic = self.atomic_mut();
+            atomic.read_vector.set_at_index(&clocks.clock, index);
+            Ok(())
+        } else {
+            Err(DataRace)
+        }
+    }
+
+    /// Detect data-races with an atomic write, either with a non-atomic read or with
+    /// a non-atomic write.
+    fn atomic_write_detect(
+        &mut self,
+        clocks: &ThreadClockSet,
+        index: VectorIdx,
+    ) -> Result<(), DataRace> {
+        log::trace!("Atomic write with vectors: {:#?} :: {:#?}", self, clocks);
+        if self.write <= clocks.clock[self.write_index] && self.read <= clocks.clock {
+            let atomic = self.atomic_mut();
+            atomic.write_vector.set_at_index(&clocks.clock, index);
+            Ok(())
+        } else {
+            Err(DataRace)
+        }
+    }
+
+    /// Detect races for non-atomic read operations at the current memory cell
+    /// returns true if a data-race is detected.
+    fn read_race_detect(
+        &mut self,
+        clocks: &ThreadClockSet,
+        index: VectorIdx,
+    ) -> Result<(), DataRace> {
+        log::trace!("Unsynchronized read with vectors: {:#?} :: {:#?}", self, clocks);
+        if self.write <= clocks.clock[self.write_index] {
+            let race_free = if let Some(atomic) = self.atomic() {
+                atomic.write_vector <= clocks.clock
+            } else {
+                true
+            };
+            if race_free {
+                self.read.set_at_index(&clocks.clock, index);
+                Ok(())
+            } else {
+                Err(DataRace)
+            }
+        } else {
+            Err(DataRace)
+        }
+    }
+
+    /// Detect races for non-atomic write operations at the current memory cell
+    /// returns true if a data-race is detected.
+    fn write_race_detect(
+        &mut self,
+        clocks: &ThreadClockSet,
+        index: VectorIdx,
+        write_type: WriteType,
+    ) -> Result<(), DataRace> {
+        log::trace!("Unsynchronized write with vectors: {:#?} :: {:#?}", self, clocks);
+        if self.write <= clocks.clock[self.write_index] && self.read <= clocks.clock {
+            let race_free = if let Some(atomic) = self.atomic() {
+                atomic.write_vector <= clocks.clock && atomic.read_vector <= clocks.clock
+            } else {
+                true
+            };
+            if race_free {
+                self.write = clocks.clock[index];
+                self.write_index = index;
+                self.write_type = write_type;
+                self.read.set_zero_vector();
+                Ok(())
+            } else {
+                Err(DataRace)
+            }
+        } else {
+            Err(DataRace)
+        }
+    }
+}
+
+/// Evaluation context extensions.
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
+    /// Atomic variant of read_scalar_at_offset.
+    fn read_scalar_at_offset_atomic(
+        &self,
+        op: &OpTy<'tcx, Provenance>,
+        offset: u64,
+        layout: TyAndLayout<'tcx>,
+        atomic: AtomicReadOrd,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+        let value_place = this.deref_operand_and_offset(op, offset, layout)?;
+        this.read_scalar_atomic(&value_place, atomic)
+    }
+
+    /// Atomic variant of write_scalar_at_offset.
+    fn write_scalar_at_offset_atomic(
+        &mut self,
+        op: &OpTy<'tcx, Provenance>,
+        offset: u64,
+        value: impl Into<Scalar<Provenance>>,
+        layout: TyAndLayout<'tcx>,
+        atomic: AtomicWriteOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let value_place = this.deref_operand_and_offset(op, offset, layout)?;
+        this.write_scalar_atomic(value.into(), &value_place, atomic)
+    }
+
+    /// Perform an atomic read operation at the memory location.
+    fn read_scalar_atomic(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicReadOrd,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+        this.atomic_access_check(place)?;
+        // This will read from the last store in the modification order of this location. In case
+        // weak memory emulation is enabled, this may not be the store we will pick to actually read from and return.
+        // This is fine with StackedBorrow and race checks because they don't concern metadata on
+        // the *value* (including the associated provenance if this is an AtomicPtr) at this location.
+        // Only metadata on the location itself is used.
+        let scalar = this.allow_data_races_ref(move |this| this.read_scalar(&place.into()))?;
+        this.validate_overlapping_atomic(place)?;
+        this.buffered_atomic_read(place, atomic, scalar, || {
+            this.validate_atomic_load(place, atomic)
+        })
+    }
+
+    /// Perform an atomic write operation at the memory location.
+    fn write_scalar_atomic(
+        &mut self,
+        val: Scalar<Provenance>,
+        dest: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicWriteOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        this.atomic_access_check(dest)?;
+
+        this.validate_overlapping_atomic(dest)?;
+        this.allow_data_races_mut(move |this| this.write_scalar(val, &dest.into()))?;
+        this.validate_atomic_store(dest, atomic)?;
+        // FIXME: it's not possible to get the value before write_scalar. A read_scalar will cause
+        // side effects from a read the program did not perform. So we have to initialise
+        // the store buffer with the value currently being written
+        // ONCE this is fixed please remove the hack in buffered_atomic_write() in weak_memory.rs
+        // https://github.com/rust-lang/miri/issues/2164
+        this.buffered_atomic_write(val, dest, atomic, val)
+    }
+
+    /// Perform an atomic operation on a memory location.
+    fn atomic_op_immediate(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        rhs: &ImmTy<'tcx, Provenance>,
+        op: mir::BinOp,
+        neg: bool,
+        atomic: AtomicRwOrd,
+    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
+        let this = self.eval_context_mut();
+        this.atomic_access_check(place)?;
+
+        this.validate_overlapping_atomic(place)?;
+        let old = this.allow_data_races_mut(|this| this.read_immediate(&place.into()))?;
+
+        // Atomics wrap around on overflow.
+        let val = this.binary_op(op, &old, rhs)?;
+        let val = if neg { this.unary_op(mir::UnOp::Not, &val)? } else { val };
+        this.allow_data_races_mut(|this| this.write_immediate(*val, &place.into()))?;
+
+        this.validate_atomic_rmw(place, atomic)?;
+
+        this.buffered_atomic_rmw(val.to_scalar(), place, atomic, old.to_scalar())?;
+        Ok(old)
+    }
+
+    /// Perform an atomic exchange with a memory place and a new
+    /// scalar value, the old value is returned.
+    fn atomic_exchange_scalar(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        new: Scalar<Provenance>,
+        atomic: AtomicRwOrd,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+        this.atomic_access_check(place)?;
+
+        this.validate_overlapping_atomic(place)?;
+        let old = this.allow_data_races_mut(|this| this.read_scalar(&place.into()))?;
+        this.allow_data_races_mut(|this| this.write_scalar(new, &place.into()))?;
+
+        this.validate_atomic_rmw(place, atomic)?;
+
+        this.buffered_atomic_rmw(new, place, atomic, old)?;
+        Ok(old)
+    }
+
+    /// Perform an conditional atomic exchange with a memory place and a new
+    /// scalar value, the old value is returned.
+    fn atomic_min_max_scalar(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        rhs: ImmTy<'tcx, Provenance>,
+        min: bool,
+        atomic: AtomicRwOrd,
+    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
+        let this = self.eval_context_mut();
+        this.atomic_access_check(place)?;
+
+        this.validate_overlapping_atomic(place)?;
+        let old = this.allow_data_races_mut(|this| this.read_immediate(&place.into()))?;
+        let lt = this.binary_op(mir::BinOp::Lt, &old, &rhs)?.to_scalar().to_bool()?;
+
+        let new_val = if min {
+            if lt { &old } else { &rhs }
+        } else {
+            if lt { &rhs } else { &old }
+        };
+
+        this.allow_data_races_mut(|this| this.write_immediate(**new_val, &place.into()))?;
+
+        this.validate_atomic_rmw(place, atomic)?;
+
+        this.buffered_atomic_rmw(new_val.to_scalar(), place, atomic, old.to_scalar())?;
+
+        // Return the old value.
+        Ok(old)
+    }
+
+    /// Perform an atomic compare and exchange at a given memory location.
+    /// On success an atomic RMW operation is performed and on failure
+    /// only an atomic read occurs. If `can_fail_spuriously` is true,
+    /// then we treat it as a "compare_exchange_weak" operation, and
+    /// some portion of the time fail even when the values are actually
+    /// identical.
+    fn atomic_compare_exchange_scalar(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        expect_old: &ImmTy<'tcx, Provenance>,
+        new: Scalar<Provenance>,
+        success: AtomicRwOrd,
+        fail: AtomicReadOrd,
+        can_fail_spuriously: bool,
+    ) -> InterpResult<'tcx, Immediate<Provenance>> {
+        use rand::Rng as _;
+        let this = self.eval_context_mut();
+        this.atomic_access_check(place)?;
+
+        this.validate_overlapping_atomic(place)?;
+        // Failure ordering cannot be stronger than success ordering, therefore first attempt
+        // to read with the failure ordering and if successful then try again with the success
+        // read ordering and write in the success case.
+        // Read as immediate for the sake of `binary_op()`
+        let old = this.allow_data_races_mut(|this| this.read_immediate(&(place.into())))?;
+        // `binary_op` will bail if either of them is not a scalar.
+        let eq = this.binary_op(mir::BinOp::Eq, &old, expect_old)?;
+        // If the operation would succeed, but is "weak", fail some portion
+        // of the time, based on `success_rate`.
+        let success_rate = 1.0 - this.machine.cmpxchg_weak_failure_rate;
+        let cmpxchg_success = eq.to_scalar().to_bool()?
+            && if can_fail_spuriously {
+                this.machine.rng.get_mut().gen_bool(success_rate)
+            } else {
+                true
+            };
+        let res = Immediate::ScalarPair(old.to_scalar(), Scalar::from_bool(cmpxchg_success));
+
+        // Update ptr depending on comparison.
+        // if successful, perform a full rw-atomic validation
+        // otherwise treat this as an atomic load with the fail ordering.
+        if cmpxchg_success {
+            this.allow_data_races_mut(|this| this.write_scalar(new, &place.into()))?;
+            this.validate_atomic_rmw(place, success)?;
+            this.buffered_atomic_rmw(new, place, success, old.to_scalar())?;
+        } else {
+            this.validate_atomic_load(place, fail)?;
+            // A failed compare exchange is equivalent to a load, reading from the latest store
+            // in the modification order.
+            // Since `old` is only a value and not the store element, we need to separately
+            // find it in our store buffer and perform load_impl on it.
+            this.perform_read_on_buffered_latest(place, fail, old.to_scalar())?;
+        }
+
+        // Return the old value.
+        Ok(res)
+    }
+
+    /// Update the data-race detector for an atomic fence on the current thread.
+    fn atomic_fence(&mut self, atomic: AtomicFenceOrd) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        if let Some(data_race) = &mut this.machine.data_race {
+            data_race.maybe_perform_sync_operation(&this.machine.threads, |index, mut clocks| {
+                log::trace!("Atomic fence on {:?} with ordering {:?}", index, atomic);
+
+                // Apply data-race detection for the current fences
+                // this treats AcqRel and SeqCst as the same as an acquire
+                // and release fence applied in the same timestamp.
+                if atomic != AtomicFenceOrd::Release {
+                    // Either Acquire | AcqRel | SeqCst
+                    clocks.apply_acquire_fence();
+                }
+                if atomic != AtomicFenceOrd::Acquire {
+                    // Either Release | AcqRel | SeqCst
+                    clocks.apply_release_fence();
+                }
+                if atomic == AtomicFenceOrd::SeqCst {
+                    data_race.last_sc_fence.borrow_mut().set_at_index(&clocks.clock, index);
+                    clocks.fence_seqcst.join(&data_race.last_sc_fence.borrow());
+                    clocks.write_seqcst.join(&data_race.last_sc_write.borrow());
+                }
+
+                // Increment timestamp in case of release semantics.
+                Ok(atomic != AtomicFenceOrd::Acquire)
+            })
+        } else {
+            Ok(())
+        }
+    }
+
+    /// After all threads are done running, this allows data races to occur for subsequent
+    /// 'administrative' machine accesses (that logically happen outside of the Abstract Machine).
+    fn allow_data_races_all_threads_done(&mut self) {
+        let this = self.eval_context_ref();
+        assert!(this.have_all_terminated());
+        if let Some(data_race) = &this.machine.data_race {
+            let old = data_race.ongoing_action_data_race_free.replace(true);
+            assert!(!old, "cannot nest allow_data_races");
+        }
+    }
+}
+
+/// Vector clock metadata for a logical memory allocation.
+#[derive(Debug, Clone)]
+pub struct VClockAlloc {
+    /// Assigning each byte a MemoryCellClocks.
+    alloc_ranges: RefCell<RangeMap<MemoryCellClocks>>,
+}
+
+impl VClockAlloc {
+    /// Create a new data-race detector for newly allocated memory.
+    pub fn new_allocation(
+        global: &GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+        len: Size,
+        kind: MemoryKind<MiriMemoryKind>,
+    ) -> VClockAlloc {
+        let (alloc_timestamp, alloc_index) = match kind {
+            // User allocated and stack memory should track allocation.
+            MemoryKind::Machine(
+                MiriMemoryKind::Rust | MiriMemoryKind::C | MiriMemoryKind::WinHeap,
+            )
+            | MemoryKind::Stack => {
+                let (alloc_index, clocks) = global.current_thread_state(thread_mgr);
+                let alloc_timestamp = clocks.clock[alloc_index];
+                (alloc_timestamp, alloc_index)
+            }
+            // Other global memory should trace races but be allocated at the 0 timestamp.
+            MemoryKind::Machine(
+                MiriMemoryKind::Global
+                | MiriMemoryKind::Machine
+                | MiriMemoryKind::Runtime
+                | MiriMemoryKind::ExternStatic
+                | MiriMemoryKind::Tls,
+            )
+            | MemoryKind::CallerLocation => (0, VectorIdx::MAX_INDEX),
+        };
+        VClockAlloc {
+            alloc_ranges: RefCell::new(RangeMap::new(
+                len,
+                MemoryCellClocks::new(alloc_timestamp, alloc_index),
+            )),
+        }
+    }
+
+    // Find an index, if one exists where the value
+    // in `l` is greater than the value in `r`.
+    fn find_gt_index(l: &VClock, r: &VClock) -> Option<VectorIdx> {
+        log::trace!("Find index where not {:?} <= {:?}", l, r);
+        let l_slice = l.as_slice();
+        let r_slice = r.as_slice();
+        l_slice
+            .iter()
+            .zip(r_slice.iter())
+            .enumerate()
+            .find_map(|(idx, (&l, &r))| if l > r { Some(idx) } else { None })
+            .or_else(|| {
+                if l_slice.len() > r_slice.len() {
+                    // By invariant, if l_slice is longer
+                    // then one element must be larger.
+                    // This just validates that this is true
+                    // and reports earlier elements first.
+                    let l_remainder_slice = &l_slice[r_slice.len()..];
+                    let idx = l_remainder_slice
+                        .iter()
+                        .enumerate()
+                        .find_map(|(idx, &r)| if r == 0 { None } else { Some(idx) })
+                        .expect("Invalid VClock Invariant");
+                    Some(idx + r_slice.len())
+                } else {
+                    None
+                }
+            })
+            .map(VectorIdx::new)
+    }
+
+    /// Report a data-race found in the program.
+    /// This finds the two racing threads and the type
+    /// of data-race that occurred. This will also
+    /// return info about the memory location the data-race
+    /// occurred in.
+    #[cold]
+    #[inline(never)]
+    fn report_data_race<'tcx>(
+        global: &GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+        range: &MemoryCellClocks,
+        action: &str,
+        is_atomic: bool,
+        ptr_dbg: Pointer<AllocId>,
+    ) -> InterpResult<'tcx> {
+        let (current_index, current_clocks) = global.current_thread_state(thread_mgr);
+        let write_clock;
+        let (other_action, other_thread, _other_clock) = if range.write
+            > current_clocks.clock[range.write_index]
+        {
+            // Convert the write action into the vector clock it
+            // represents for diagnostic purposes.
+            write_clock = VClock::new_with_index(range.write_index, range.write);
+            (range.write_type.get_descriptor(), range.write_index, &write_clock)
+        } else if let Some(idx) = Self::find_gt_index(&range.read, &current_clocks.clock) {
+            ("Read", idx, &range.read)
+        } else if !is_atomic {
+            if let Some(atomic) = range.atomic() {
+                if let Some(idx) = Self::find_gt_index(&atomic.write_vector, &current_clocks.clock)
+                {
+                    ("Atomic Store", idx, &atomic.write_vector)
+                } else if let Some(idx) =
+                    Self::find_gt_index(&atomic.read_vector, &current_clocks.clock)
+                {
+                    ("Atomic Load", idx, &atomic.read_vector)
+                } else {
+                    unreachable!(
+                        "Failed to report data-race for non-atomic operation: no race found"
+                    )
+                }
+            } else {
+                unreachable!(
+                    "Failed to report data-race for non-atomic operation: no atomic component"
+                )
+            }
+        } else {
+            unreachable!("Failed to report data-race for atomic operation")
+        };
+
+        // Load elaborated thread information about the racing thread actions.
+        let current_thread_info = global.print_thread_metadata(thread_mgr, current_index);
+        let other_thread_info = global.print_thread_metadata(thread_mgr, other_thread);
+
+        // Throw the data-race detection.
+        throw_ub_format!(
+            "Data race detected between {} on {} and {} on {} at {:?}",
+            action,
+            current_thread_info,
+            other_action,
+            other_thread_info,
+            ptr_dbg,
+        )
+    }
+
+    /// Detect racing atomic read and writes (not data races)
+    /// on every byte of the current access range
+    pub(super) fn race_free_with_atomic(
+        &self,
+        range: AllocRange,
+        global: &GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> bool {
+        if global.race_detecting() {
+            let (_, clocks) = global.current_thread_state(thread_mgr);
+            let alloc_ranges = self.alloc_ranges.borrow();
+            for (_, range) in alloc_ranges.iter(range.start, range.size) {
+                if !range.race_free_with_atomic(&clocks) {
+                    return false;
+                }
+            }
+        }
+        true
+    }
+
+    /// Detect data-races for an unsynchronized read operation, will not perform
+    /// data-race detection if `race_detecting()` is false, either due to no threads
+    /// being created or if it is temporarily disabled during a racy read or write
+    /// operation for which data-race detection is handled separately, for example
+    /// atomic read operations.
+    pub fn read<'tcx>(
+        &self,
+        alloc_id: AllocId,
+        range: AllocRange,
+        global: &GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> InterpResult<'tcx> {
+        if global.race_detecting() {
+            let (index, clocks) = global.current_thread_state(thread_mgr);
+            let mut alloc_ranges = self.alloc_ranges.borrow_mut();
+            for (offset, range) in alloc_ranges.iter_mut(range.start, range.size) {
+                if let Err(DataRace) = range.read_race_detect(&clocks, index) {
+                    // Report data-race.
+                    return Self::report_data_race(
+                        global,
+                        thread_mgr,
+                        range,
+                        "Read",
+                        false,
+                        Pointer::new(alloc_id, offset),
+                    );
+                }
+            }
+            Ok(())
+        } else {
+            Ok(())
+        }
+    }
+
+    // Shared code for detecting data-races on unique access to a section of memory
+    fn unique_access<'tcx>(
+        &mut self,
+        alloc_id: AllocId,
+        range: AllocRange,
+        write_type: WriteType,
+        global: &mut GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> InterpResult<'tcx> {
+        if global.race_detecting() {
+            let (index, clocks) = global.current_thread_state(thread_mgr);
+            for (offset, range) in self.alloc_ranges.get_mut().iter_mut(range.start, range.size) {
+                if let Err(DataRace) = range.write_race_detect(&clocks, index, write_type) {
+                    // Report data-race
+                    return Self::report_data_race(
+                        global,
+                        thread_mgr,
+                        range,
+                        write_type.get_descriptor(),
+                        false,
+                        Pointer::new(alloc_id, offset),
+                    );
+                }
+            }
+            Ok(())
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Detect data-races for an unsynchronized write operation, will not perform
+    /// data-race threads if `race_detecting()` is false, either due to no threads
+    /// being created or if it is temporarily disabled during a racy read or write
+    /// operation
+    pub fn write<'tcx>(
+        &mut self,
+        alloc_id: AllocId,
+        range: AllocRange,
+        global: &mut GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> InterpResult<'tcx> {
+        self.unique_access(alloc_id, range, WriteType::Write, global, thread_mgr)
+    }
+
+    /// Detect data-races for an unsynchronized deallocate operation, will not perform
+    /// data-race threads if `race_detecting()` is false, either due to no threads
+    /// being created or if it is temporarily disabled during a racy read or write
+    /// operation
+    pub fn deallocate<'tcx>(
+        &mut self,
+        alloc_id: AllocId,
+        range: AllocRange,
+        global: &mut GlobalState,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> InterpResult<'tcx> {
+        self.unique_access(alloc_id, range, WriteType::Deallocate, global, thread_mgr)
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextPrivExt<'mir, 'tcx> for MiriInterpCx<'mir, 'tcx> {}
+trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
+    /// Temporarily allow data-races to occur. This should only be used in
+    /// one of these cases:
+    /// - One of the appropriate `validate_atomic` functions will be called to
+    /// to treat a memory access as atomic.
+    /// - The memory being accessed should be treated as internal state, that
+    /// cannot be accessed by the interpreted program.
+    /// - Execution of the interpreted program execution has halted.
+    #[inline]
+    fn allow_data_races_ref<R>(&self, op: impl FnOnce(&MiriInterpCx<'mir, 'tcx>) -> R) -> R {
+        let this = self.eval_context_ref();
+        if let Some(data_race) = &this.machine.data_race {
+            let old = data_race.ongoing_action_data_race_free.replace(true);
+            assert!(!old, "cannot nest allow_data_races");
+        }
+        let result = op(this);
+        if let Some(data_race) = &this.machine.data_race {
+            data_race.ongoing_action_data_race_free.set(false);
+        }
+        result
+    }
+
+    /// Same as `allow_data_races_ref`, this temporarily disables any data-race detection and
+    /// so should only be used for atomic operations or internal state that the program cannot
+    /// access.
+    #[inline]
+    fn allow_data_races_mut<R>(
+        &mut self,
+        op: impl FnOnce(&mut MiriInterpCx<'mir, 'tcx>) -> R,
+    ) -> R {
+        let this = self.eval_context_mut();
+        if let Some(data_race) = &this.machine.data_race {
+            let old = data_race.ongoing_action_data_race_free.replace(true);
+            assert!(!old, "cannot nest allow_data_races");
+        }
+        let result = op(this);
+        if let Some(data_race) = &this.machine.data_race {
+            data_race.ongoing_action_data_race_free.set(false);
+        }
+        result
+    }
+
+    /// Checks that an atomic access is legal at the given place.
+    fn atomic_access_check(&self, place: &MPlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+        // Check alignment requirements. Atomics must always be aligned to their size,
+        // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
+        // be 8-aligned).
+        let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
+        this.check_ptr_access_align(
+            place.ptr,
+            place.layout.size,
+            align,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
+        // Ensure the allocation is mutable. Even failing (read-only) compare_exchange need mutable
+        // memory on many targets (i.e., they segfault if taht memory is mapped read-only), and
+        // atomic loads can be implemented via compare_exchange on some targets. There could
+        // possibly be some very specific exceptions to this, see
+        // <https://github.com/rust-lang/miri/pull/2464#discussion_r939636130> for details.
+        // We avoid `get_ptr_alloc` since we do *not* want to run the access hooks -- the actual
+        // access will happen later.
+        let (alloc_id, _offset, _prov) =
+            this.ptr_try_get_alloc_id(place.ptr).expect("there are no zero-sized atomic accesses");
+        if this.get_alloc_mutability(alloc_id)? == Mutability::Not {
+            // FIXME: make this prettier, once these messages have separate title/span/help messages.
+            throw_ub_format!(
+                "atomic operations cannot be performed on read-only memory\n\
+                many platforms require atomic read-modify-write instructions to be performed on writeable memory, even if the operation fails \
+                (and is hence nominally read-only)\n\
+                some platforms implement (some) atomic loads via compare-exchange, which means they do not work on read-only memory; \
+                it is possible that we could have an exception permitting this for specific kinds of loads\n\
+                please report an issue at <https://github.com/rust-lang/miri/issues> if this is a problem for you"
+            );
+        }
+        Ok(())
+    }
+
+    /// Update the data-race detector for an atomic read occurring at the
+    /// associated memory-place and on the current thread.
+    fn validate_atomic_load(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicReadOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+        this.validate_overlapping_atomic(place)?;
+        this.validate_atomic_op(
+            place,
+            atomic,
+            "Atomic Load",
+            move |memory, clocks, index, atomic| {
+                if atomic == AtomicReadOrd::Relaxed {
+                    memory.load_relaxed(&mut *clocks, index)
+                } else {
+                    memory.load_acquire(&mut *clocks, index)
+                }
+            },
+        )
+    }
+
+    /// Update the data-race detector for an atomic write occurring at the
+    /// associated memory-place and on the current thread.
+    fn validate_atomic_store(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicWriteOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        this.validate_overlapping_atomic(place)?;
+        this.validate_atomic_op(
+            place,
+            atomic,
+            "Atomic Store",
+            move |memory, clocks, index, atomic| {
+                if atomic == AtomicWriteOrd::Relaxed {
+                    memory.store_relaxed(clocks, index)
+                } else {
+                    memory.store_release(clocks, index)
+                }
+            },
+        )
+    }
+
+    /// Update the data-race detector for an atomic read-modify-write occurring
+    /// at the associated memory place and on the current thread.
+    fn validate_atomic_rmw(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicRwOrd,
+    ) -> InterpResult<'tcx> {
+        use AtomicRwOrd::*;
+        let acquire = matches!(atomic, Acquire | AcqRel | SeqCst);
+        let release = matches!(atomic, Release | AcqRel | SeqCst);
+        let this = self.eval_context_mut();
+        this.validate_overlapping_atomic(place)?;
+        this.validate_atomic_op(place, atomic, "Atomic RMW", move |memory, clocks, index, _| {
+            if acquire {
+                memory.load_acquire(clocks, index)?;
+            } else {
+                memory.load_relaxed(clocks, index)?;
+            }
+            if release {
+                memory.rmw_release(clocks, index)
+            } else {
+                memory.rmw_relaxed(clocks, index)
+            }
+        })
+    }
+
+    /// Generic atomic operation implementation
+    fn validate_atomic_op<A: Debug + Copy>(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: A,
+        description: &str,
+        mut op: impl FnMut(
+            &mut MemoryCellClocks,
+            &mut ThreadClockSet,
+            VectorIdx,
+            A,
+        ) -> Result<(), DataRace>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+        if let Some(data_race) = &this.machine.data_race {
+            if data_race.race_detecting() {
+                let size = place.layout.size;
+                let (alloc_id, base_offset, _prov) = this.ptr_get_alloc_id(place.ptr)?;
+                // Load and log the atomic operation.
+                // Note that atomic loads are possible even from read-only allocations, so `get_alloc_extra_mut` is not an option.
+                let alloc_meta = this.get_alloc_extra(alloc_id)?.data_race.as_ref().unwrap();
+                log::trace!(
+                    "Atomic op({}) with ordering {:?} on {:?} (size={})",
+                    description,
+                    &atomic,
+                    place.ptr,
+                    size.bytes()
+                );
+
+                // Perform the atomic operation.
+                data_race.maybe_perform_sync_operation(
+                    &this.machine.threads,
+                    |index, mut clocks| {
+                        for (offset, range) in
+                            alloc_meta.alloc_ranges.borrow_mut().iter_mut(base_offset, size)
+                        {
+                            if let Err(DataRace) = op(range, &mut clocks, index, atomic) {
+                                mem::drop(clocks);
+                                return VClockAlloc::report_data_race(
+                                    data_race,
+                                    &this.machine.threads,
+                                    range,
+                                    description,
+                                    true,
+                                    Pointer::new(alloc_id, offset),
+                                )
+                                .map(|_| true);
+                            }
+                        }
+
+                        // This conservatively assumes all operations have release semantics
+                        Ok(true)
+                    },
+                )?;
+
+                // Log changes to atomic memory.
+                if log::log_enabled!(log::Level::Trace) {
+                    for (_offset, range) in alloc_meta.alloc_ranges.borrow().iter(base_offset, size)
+                    {
+                        log::trace!(
+                            "Updated atomic memory({:?}, size={}) to {:#?}",
+                            place.ptr,
+                            size.bytes(),
+                            range.atomic_ops
+                        );
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+/// Extra metadata associated with a thread.
+#[derive(Debug, Clone, Default)]
+struct ThreadExtraState {
+    /// The current vector index in use by the
+    /// thread currently, this is set to None
+    /// after the vector index has been re-used
+    /// and hence the value will never need to be
+    /// read during data-race reporting.
+    vector_index: Option<VectorIdx>,
+
+    /// Thread termination vector clock, this
+    /// is set on thread termination and is used
+    /// for joining on threads since the vector_index
+    /// may be re-used when the join operation occurs.
+    termination_vector_clock: Option<VClock>,
+}
+
+/// Global data-race detection state, contains the currently
+/// executing thread as well as the vector-clocks associated
+/// with each of the threads.
+// FIXME: it is probably better to have one large RefCell, than to have so many small ones.
+#[derive(Debug, Clone)]
+pub struct GlobalState {
+    /// Set to true once the first additional
+    /// thread has launched, due to the dependency
+    /// between before and after a thread launch.
+    /// Any data-races must be recorded after this
+    /// so concurrent execution can ignore recording
+    /// any data-races.
+    multi_threaded: Cell<bool>,
+
+    /// A flag to mark we are currently performing
+    /// a data race free action (such as atomic access)
+    /// to supress the race detector
+    ongoing_action_data_race_free: Cell<bool>,
+
+    /// Mapping of a vector index to a known set of thread
+    /// clocks, this is not directly mapping from a thread id
+    /// since it may refer to multiple threads.
+    vector_clocks: RefCell<IndexVec<VectorIdx, ThreadClockSet>>,
+
+    /// Mapping of a given vector index to the current thread
+    /// that the execution is representing, this may change
+    /// if a vector index is re-assigned to a new thread.
+    vector_info: RefCell<IndexVec<VectorIdx, ThreadId>>,
+
+    /// The mapping of a given thread to associated thread metadata.
+    thread_info: RefCell<IndexVec<ThreadId, ThreadExtraState>>,
+
+    /// Potential vector indices that could be re-used on thread creation
+    /// values are inserted here on after the thread has terminated and
+    /// been joined with, and hence may potentially become free
+    /// for use as the index for a new thread.
+    /// Elements in this set may still require the vector index to
+    /// report data-races, and can only be re-used after all
+    /// active vector-clocks catch up with the threads timestamp.
+    reuse_candidates: RefCell<FxHashSet<VectorIdx>>,
+
+    /// This contains threads that have terminated, but not yet joined
+    /// and so cannot become re-use candidates until a join operation
+    /// occurs.
+    /// The associated vector index will be moved into re-use candidates
+    /// after the join operation occurs.
+    terminated_threads: RefCell<FxHashMap<ThreadId, VectorIdx>>,
+
+    /// The timestamp of last SC fence performed by each thread
+    last_sc_fence: RefCell<VClock>,
+
+    /// The timestamp of last SC write performed by each thread
+    last_sc_write: RefCell<VClock>,
+
+    /// Track when an outdated (weak memory) load happens.
+    pub track_outdated_loads: bool,
+}
+
+impl GlobalState {
+    /// Create a new global state, setup with just thread-id=0
+    /// advanced to timestamp = 1.
+    pub fn new(config: &MiriConfig) -> Self {
+        let mut global_state = GlobalState {
+            multi_threaded: Cell::new(false),
+            ongoing_action_data_race_free: Cell::new(false),
+            vector_clocks: RefCell::new(IndexVec::new()),
+            vector_info: RefCell::new(IndexVec::new()),
+            thread_info: RefCell::new(IndexVec::new()),
+            reuse_candidates: RefCell::new(FxHashSet::default()),
+            terminated_threads: RefCell::new(FxHashMap::default()),
+            last_sc_fence: RefCell::new(VClock::default()),
+            last_sc_write: RefCell::new(VClock::default()),
+            track_outdated_loads: config.track_outdated_loads,
+        };
+
+        // Setup the main-thread since it is not explicitly created:
+        // uses vector index and thread-id 0.
+        let index = global_state.vector_clocks.get_mut().push(ThreadClockSet::default());
+        global_state.vector_info.get_mut().push(ThreadId::new(0));
+        global_state
+            .thread_info
+            .get_mut()
+            .push(ThreadExtraState { vector_index: Some(index), termination_vector_clock: None });
+
+        global_state
+    }
+
+    // We perform data race detection when there are more than 1 active thread
+    // and we have not temporarily disabled race detection to perform something
+    // data race free
+    fn race_detecting(&self) -> bool {
+        self.multi_threaded.get() && !self.ongoing_action_data_race_free.get()
+    }
+
+    pub fn ongoing_action_data_race_free(&self) -> bool {
+        self.ongoing_action_data_race_free.get()
+    }
+
+    // Try to find vector index values that can potentially be re-used
+    // by a new thread instead of a new vector index being created.
+    fn find_vector_index_reuse_candidate(&self) -> Option<VectorIdx> {
+        let mut reuse = self.reuse_candidates.borrow_mut();
+        let vector_clocks = self.vector_clocks.borrow();
+        let vector_info = self.vector_info.borrow();
+        let terminated_threads = self.terminated_threads.borrow();
+        for &candidate in reuse.iter() {
+            let target_timestamp = vector_clocks[candidate].clock[candidate];
+            if vector_clocks.iter_enumerated().all(|(clock_idx, clock)| {
+                // The thread happens before the clock, and hence cannot report
+                // a data-race with this the candidate index.
+                let no_data_race = clock.clock[candidate] >= target_timestamp;
+
+                // The vector represents a thread that has terminated and hence cannot
+                // report a data-race with the candidate index.
+                let thread_id = vector_info[clock_idx];
+                let vector_terminated =
+                    reuse.contains(&clock_idx) || terminated_threads.contains_key(&thread_id);
+
+                // The vector index cannot report a race with the candidate index
+                // and hence allows the candidate index to be re-used.
+                no_data_race || vector_terminated
+            }) {
+                // All vector clocks for each vector index are equal to
+                // the target timestamp, and the thread is known to have
+                // terminated, therefore this vector clock index cannot
+                // report any more data-races.
+                assert!(reuse.remove(&candidate));
+                return Some(candidate);
+            }
+        }
+        None
+    }
+
+    // Hook for thread creation, enabled multi-threaded execution and marks
+    // the current thread timestamp as happening-before the current thread.
+    #[inline]
+    pub fn thread_created(&mut self, thread_mgr: &ThreadManager<'_, '_>, thread: ThreadId) {
+        let current_index = self.current_index(thread_mgr);
+
+        // Enable multi-threaded execution, there are now at least two threads
+        // so data-races are now possible.
+        self.multi_threaded.set(true);
+
+        // Load and setup the associated thread metadata
+        let mut thread_info = self.thread_info.borrow_mut();
+        thread_info.ensure_contains_elem(thread, Default::default);
+
+        // Assign a vector index for the thread, attempting to re-use an old
+        // vector index that can no longer report any data-races if possible.
+        let created_index = if let Some(reuse_index) = self.find_vector_index_reuse_candidate() {
+            // Now re-configure the re-use candidate, increment the clock
+            // for the new sync use of the vector.
+            let vector_clocks = self.vector_clocks.get_mut();
+            vector_clocks[reuse_index].increment_clock(reuse_index);
+
+            // Locate the old thread the vector was associated with and update
+            // it to represent the new thread instead.
+            let vector_info = self.vector_info.get_mut();
+            let old_thread = vector_info[reuse_index];
+            vector_info[reuse_index] = thread;
+
+            // Mark the thread the vector index was associated with as no longer
+            // representing a thread index.
+            thread_info[old_thread].vector_index = None;
+
+            reuse_index
+        } else {
+            // No vector re-use candidates available, instead create
+            // a new vector index.
+            let vector_info = self.vector_info.get_mut();
+            vector_info.push(thread)
+        };
+
+        log::trace!("Creating thread = {:?} with vector index = {:?}", thread, created_index);
+
+        // Mark the chosen vector index as in use by the thread.
+        thread_info[thread].vector_index = Some(created_index);
+
+        // Create a thread clock set if applicable.
+        let vector_clocks = self.vector_clocks.get_mut();
+        if created_index == vector_clocks.next_index() {
+            vector_clocks.push(ThreadClockSet::default());
+        }
+
+        // Now load the two clocks and configure the initial state.
+        let (current, created) = vector_clocks.pick2_mut(current_index, created_index);
+
+        // Join the created with current, since the current threads
+        // previous actions happen-before the created thread.
+        created.join_with(current);
+
+        // Advance both threads after the synchronized operation.
+        // Both operations are considered to have release semantics.
+        current.increment_clock(current_index);
+        created.increment_clock(created_index);
+    }
+
+    /// Hook on a thread join to update the implicit happens-before relation between the joined
+    /// thread (the joinee, the thread that someone waited on) and the current thread (the joiner,
+    /// the thread who was waiting).
+    #[inline]
+    pub fn thread_joined(
+        &mut self,
+        thread_mgr: &ThreadManager<'_, '_>,
+        joiner: ThreadId,
+        joinee: ThreadId,
+    ) {
+        let clocks_vec = self.vector_clocks.get_mut();
+        let thread_info = self.thread_info.get_mut();
+
+        // Load the vector clock of the current thread.
+        let current_index = thread_info[joiner]
+            .vector_index
+            .expect("Performed thread join on thread with no assigned vector");
+        let current = &mut clocks_vec[current_index];
+
+        // Load the associated vector clock for the terminated thread.
+        let join_clock = thread_info[joinee]
+            .termination_vector_clock
+            .as_ref()
+            .expect("Joined with thread but thread has not terminated");
+
+        // The join thread happens-before the current thread
+        // so update the current vector clock.
+        // Is not a release operation so the clock is not incremented.
+        current.clock.join(join_clock);
+
+        // Check the number of live threads, if the value is 1
+        // then test for potentially disabling multi-threaded execution.
+        if thread_mgr.get_live_thread_count() == 1 {
+            // May potentially be able to disable multi-threaded execution.
+            let current_clock = &clocks_vec[current_index];
+            if clocks_vec
+                .iter_enumerated()
+                .all(|(idx, clocks)| clocks.clock[idx] <= current_clock.clock[idx])
+            {
+                // All thread terminations happen-before the current clock
+                // therefore no data-races can be reported until a new thread
+                // is created, so disable multi-threaded execution.
+                self.multi_threaded.set(false);
+            }
+        }
+
+        // If the thread is marked as terminated but not joined
+        // then move the thread to the re-use set.
+        let termination = self.terminated_threads.get_mut();
+        if let Some(index) = termination.remove(&joinee) {
+            let reuse = self.reuse_candidates.get_mut();
+            reuse.insert(index);
+        }
+    }
+
+    /// On thread termination, the vector-clock may re-used
+    /// in the future once all remaining thread-clocks catch
+    /// up with the time index of the terminated thread.
+    /// This assigns thread termination with a unique index
+    /// which will be used to join the thread
+    /// This should be called strictly before any calls to
+    /// `thread_joined`.
+    #[inline]
+    pub fn thread_terminated(&mut self, thread_mgr: &ThreadManager<'_, '_>) {
+        let current_index = self.current_index(thread_mgr);
+
+        // Increment the clock to a unique termination timestamp.
+        let vector_clocks = self.vector_clocks.get_mut();
+        let current_clocks = &mut vector_clocks[current_index];
+        current_clocks.increment_clock(current_index);
+
+        // Load the current thread id for the executing vector.
+        let vector_info = self.vector_info.get_mut();
+        let current_thread = vector_info[current_index];
+
+        // Load the current thread metadata, and move to a terminated
+        // vector state. Setting up the vector clock all join operations
+        // will use.
+        let thread_info = self.thread_info.get_mut();
+        let current = &mut thread_info[current_thread];
+        current.termination_vector_clock = Some(current_clocks.clock.clone());
+
+        // Add this thread as a candidate for re-use after a thread join
+        // occurs.
+        let termination = self.terminated_threads.get_mut();
+        termination.insert(current_thread, current_index);
+    }
+
+    /// Attempt to perform a synchronized operation, this
+    /// will perform no operation if multi-threading is
+    /// not currently enabled.
+    /// Otherwise it will increment the clock for the current
+    /// vector before and after the operation for data-race
+    /// detection between any happens-before edges the
+    /// operation may create.
+    fn maybe_perform_sync_operation<'tcx>(
+        &self,
+        thread_mgr: &ThreadManager<'_, '_>,
+        op: impl FnOnce(VectorIdx, RefMut<'_, ThreadClockSet>) -> InterpResult<'tcx, bool>,
+    ) -> InterpResult<'tcx> {
+        if self.multi_threaded.get() {
+            let (index, clocks) = self.current_thread_state_mut(thread_mgr);
+            if op(index, clocks)? {
+                let (_, mut clocks) = self.current_thread_state_mut(thread_mgr);
+                clocks.increment_clock(index);
+            }
+        }
+        Ok(())
+    }
+
+    /// Internal utility to identify a thread stored internally
+    /// returns the id and the name for better diagnostics.
+    fn print_thread_metadata(
+        &self,
+        thread_mgr: &ThreadManager<'_, '_>,
+        vector: VectorIdx,
+    ) -> String {
+        let thread = self.vector_info.borrow()[vector];
+        let thread_name = thread_mgr.get_thread_name(thread);
+        format!("thread `{}`", String::from_utf8_lossy(thread_name))
+    }
+
+    /// Acquire a lock, express that the previous call of
+    /// `validate_lock_release` must happen before this.
+    /// As this is an acquire operation, the thread timestamp is not
+    /// incremented.
+    pub fn validate_lock_acquire(&self, lock: &VClock, thread: ThreadId) {
+        let (_, mut clocks) = self.load_thread_state_mut(thread);
+        clocks.clock.join(lock);
+    }
+
+    /// Release a lock handle, express that this happens-before
+    /// any subsequent calls to `validate_lock_acquire`.
+    /// For normal locks this should be equivalent to `validate_lock_release_shared`
+    /// since an acquire operation should have occurred before, however
+    /// for futex & condvar operations this is not the case and this
+    /// operation must be used.
+    pub fn validate_lock_release(&self, lock: &mut VClock, thread: ThreadId) {
+        let (index, mut clocks) = self.load_thread_state_mut(thread);
+        lock.clone_from(&clocks.clock);
+        clocks.increment_clock(index);
+    }
+
+    /// Release a lock handle, express that this happens-before
+    /// any subsequent calls to `validate_lock_acquire` as well
+    /// as any previous calls to this function after any
+    /// `validate_lock_release` calls.
+    /// For normal locks this should be equivalent to `validate_lock_release`.
+    /// This function only exists for joining over the set of concurrent readers
+    /// in a read-write lock and should not be used for anything else.
+    pub fn validate_lock_release_shared(&self, lock: &mut VClock, thread: ThreadId) {
+        let (index, mut clocks) = self.load_thread_state_mut(thread);
+        lock.join(&clocks.clock);
+        clocks.increment_clock(index);
+    }
+
+    /// Load the vector index used by the given thread as well as the set of vector clocks
+    /// used by the thread.
+    #[inline]
+    fn load_thread_state_mut(&self, thread: ThreadId) -> (VectorIdx, RefMut<'_, ThreadClockSet>) {
+        let index = self.thread_info.borrow()[thread]
+            .vector_index
+            .expect("Loading thread state for thread with no assigned vector");
+        let ref_vector = self.vector_clocks.borrow_mut();
+        let clocks = RefMut::map(ref_vector, |vec| &mut vec[index]);
+        (index, clocks)
+    }
+
+    /// Load the current vector clock in use and the current set of thread clocks
+    /// in use for the vector.
+    #[inline]
+    pub(super) fn current_thread_state(
+        &self,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> (VectorIdx, Ref<'_, ThreadClockSet>) {
+        let index = self.current_index(thread_mgr);
+        let ref_vector = self.vector_clocks.borrow();
+        let clocks = Ref::map(ref_vector, |vec| &vec[index]);
+        (index, clocks)
+    }
+
+    /// Load the current vector clock in use and the current set of thread clocks
+    /// in use for the vector mutably for modification.
+    #[inline]
+    pub(super) fn current_thread_state_mut(
+        &self,
+        thread_mgr: &ThreadManager<'_, '_>,
+    ) -> (VectorIdx, RefMut<'_, ThreadClockSet>) {
+        let index = self.current_index(thread_mgr);
+        let ref_vector = self.vector_clocks.borrow_mut();
+        let clocks = RefMut::map(ref_vector, |vec| &mut vec[index]);
+        (index, clocks)
+    }
+
+    /// Return the current thread, should be the same
+    /// as the data-race active thread.
+    #[inline]
+    fn current_index(&self, thread_mgr: &ThreadManager<'_, '_>) -> VectorIdx {
+        let active_thread_id = thread_mgr.get_active_thread_id();
+        self.thread_info.borrow()[active_thread_id]
+            .vector_index
+            .expect("active thread has no assigned vector")
+    }
+
+    // SC ATOMIC STORE rule in the paper.
+    pub(super) fn sc_write(&self, thread_mgr: &ThreadManager<'_, '_>) {
+        let (index, clocks) = self.current_thread_state(thread_mgr);
+        self.last_sc_write.borrow_mut().set_at_index(&clocks.clock, index);
+    }
+
+    // SC ATOMIC READ rule in the paper.
+    pub(super) fn sc_read(&self, thread_mgr: &ThreadManager<'_, '_>) {
+        let (.., mut clocks) = self.current_thread_state_mut(thread_mgr);
+        clocks.read_seqcst.join(&self.last_sc_fence.borrow());
+    }
+}
diff --git a/src/tools/miri/src/concurrency/mod.rs b/src/tools/miri/src/concurrency/mod.rs
new file mode 100644
index 000000000000..61ef3d5640e0
--- /dev/null
+++ b/src/tools/miri/src/concurrency/mod.rs
@@ -0,0 +1,6 @@
+pub mod data_race;
+mod range_object_map;
+pub mod sync;
+pub mod thread;
+mod vector_clock;
+pub mod weak_memory;
diff --git a/src/tools/miri/src/concurrency/range_object_map.rs b/src/tools/miri/src/concurrency/range_object_map.rs
new file mode 100644
index 000000000000..50d3f8c9b20e
--- /dev/null
+++ b/src/tools/miri/src/concurrency/range_object_map.rs
@@ -0,0 +1,277 @@
+//! Implements a map from allocation ranges to data. This is somewhat similar to RangeMap, but the
+//! ranges and data are discrete and non-splittable -- they represent distinct "objects". An
+//! allocation in the map will always have the same range until explicitly removed
+
+use rustc_target::abi::Size;
+use std::ops::{Index, IndexMut, Range};
+
+use rustc_const_eval::interpret::AllocRange;
+
+#[derive(Clone, Debug)]
+struct Elem<T> {
+    /// The range covered by this element; never empty.
+    range: AllocRange,
+    /// The data stored for this element.
+    data: T,
+}
+
+/// Index of an allocation within the map
+type Position = usize;
+
+#[derive(Clone, Debug)]
+pub struct RangeObjectMap<T> {
+    v: Vec<Elem<T>>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum AccessType {
+    /// The access perfectly overlaps (same offset and range) with the exsiting allocation
+    PerfectlyOverlapping(Position),
+    /// The access does not touch any exising allocation
+    Empty(Position),
+    /// The access overlaps with one or more existing allocations
+    ImperfectlyOverlapping(Range<Position>),
+}
+
+impl<T> RangeObjectMap<T> {
+    pub fn new() -> Self {
+        Self { v: Vec::new() }
+    }
+
+    /// Finds the position of the allocation containing the given offset. If the offset is not
+    /// in an existing allocation, then returns Err containing the position
+    /// where such allocation should be inserted
+    fn find_offset(&self, offset: Size) -> Result<Position, Position> {
+        // We do a binary search.
+        let mut left = 0usize; // inclusive
+        let mut right = self.v.len(); // exclusive
+        loop {
+            if left == right {
+                // No element contains the given offset. But the
+                // position is where such element should be placed at.
+                return Err(left);
+            }
+            let candidate = left.checked_add(right).unwrap() / 2;
+            let elem = &self.v[candidate];
+            if offset < elem.range.start {
+                // We are too far right (offset is further left).
+                debug_assert!(candidate < right); // we are making progress
+                right = candidate;
+            } else if offset >= elem.range.end() {
+                // We are too far left (offset is further right).
+                debug_assert!(candidate >= left); // we are making progress
+                left = candidate + 1;
+            } else {
+                // This is it!
+                return Ok(candidate);
+            }
+        }
+    }
+
+    /// Determines whether a given access on `range` overlaps with
+    /// an existing allocation
+    pub fn access_type(&self, range: AllocRange) -> AccessType {
+        match self.find_offset(range.start) {
+            Ok(pos) => {
+                // Start of the range belongs to an existing object, now let's check the overlapping situation
+                let elem = &self.v[pos];
+                // FIXME: derive Eq for AllocRange in rustc
+                if elem.range.start == range.start && elem.range.size == range.size {
+                    // Happy case: perfectly overlapping access
+                    AccessType::PerfectlyOverlapping(pos)
+                } else {
+                    // FIXME: add a last() method to AllocRange that returns the last inclusive offset (end() is exclusive)
+                    let end_pos = match self.find_offset(range.end() - Size::from_bytes(1)) {
+                        // If the end lands in an existing object, add one to get the exclusive position
+                        Ok(inclusive_pos) => inclusive_pos + 1,
+                        Err(exclusive_pos) => exclusive_pos,
+                    };
+
+                    AccessType::ImperfectlyOverlapping(pos..end_pos)
+                }
+            }
+            Err(pos) => {
+                // Start of the range doesn't belong to an existing object
+                match self.find_offset(range.end() - Size::from_bytes(1)) {
+                    // Neither does the end
+                    Err(end_pos) =>
+                        if pos == end_pos {
+                            // There's nothing between the start and the end, so the range thing is empty
+                            AccessType::Empty(pos)
+                        } else {
+                            // Otherwise we have entirely covered an existing object
+                            AccessType::ImperfectlyOverlapping(pos..end_pos)
+                        },
+                    // Otherwise at least part of it overlaps with something else
+                    Ok(end_pos) => AccessType::ImperfectlyOverlapping(pos..end_pos + 1),
+                }
+            }
+        }
+    }
+
+    /// Inserts an object and its occupied range at given position
+    // The Position can be calculated from AllocRange, but the only user of AllocationMap
+    // always calls access_type before calling insert/index/index_mut, and we don't
+    // want to repeat the binary search on each time, so we ask the caller to supply Position
+    pub fn insert_at_pos(&mut self, pos: Position, range: AllocRange, data: T) {
+        self.v.insert(pos, Elem { range, data });
+        // If we aren't the first element, then our start must be greater than the preivous element's end
+        if pos > 0 {
+            assert!(self.v[pos - 1].range.end() <= range.start);
+        }
+        // If we aren't the last element, then our end must be smaller than next element's start
+        if pos < self.v.len() - 1 {
+            assert!(range.end() <= self.v[pos + 1].range.start);
+        }
+    }
+
+    pub fn remove_pos_range(&mut self, pos_range: Range<Position>) {
+        self.v.drain(pos_range);
+    }
+
+    pub fn remove_from_pos(&mut self, pos: Position) {
+        self.v.remove(pos);
+    }
+}
+
+impl<T> Index<Position> for RangeObjectMap<T> {
+    type Output = T;
+
+    fn index(&self, pos: Position) -> &Self::Output {
+        &self.v[pos].data
+    }
+}
+
+impl<T> IndexMut<Position> for RangeObjectMap<T> {
+    fn index_mut(&mut self, pos: Position) -> &mut Self::Output {
+        &mut self.v[pos].data
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use rustc_const_eval::interpret::alloc_range;
+
+    use super::*;
+
+    #[test]
+    fn empty_map() {
+        // FIXME: make Size::from_bytes const
+        let four = Size::from_bytes(4);
+        let map = RangeObjectMap::<()>::new();
+
+        // Correctly tells where we should insert the first element (at position 0)
+        assert_eq!(map.find_offset(Size::from_bytes(3)), Err(0));
+
+        // Correctly tells the access type along with the supposed position
+        assert_eq!(map.access_type(alloc_range(Size::ZERO, four)), AccessType::Empty(0));
+    }
+
+    #[test]
+    #[should_panic]
+    fn no_overlapping_inserts() {
+        let four = Size::from_bytes(4);
+
+        let mut map = RangeObjectMap::<&str>::new();
+
+        // |_|_|_|_|#|#|#|#|_|_|_|_|...
+        //  0 1 2 3 4 5 6 7 8 9 a b c d
+        map.insert_at_pos(0, alloc_range(four, four), "#");
+        // |_|_|_|_|#|#|#|#|_|_|_|_|...
+        //  0 ^ ^ ^ ^ 5 6 7 8 9 a b c d
+        map.insert_at_pos(0, alloc_range(Size::from_bytes(1), four), "@");
+    }
+
+    #[test]
+    fn boundaries() {
+        let four = Size::from_bytes(4);
+
+        let mut map = RangeObjectMap::<&str>::new();
+
+        // |#|#|#|#|_|_|...
+        //  0 1 2 3 4 5
+        map.insert_at_pos(0, alloc_range(Size::ZERO, four), "#");
+        // |#|#|#|#|_|_|...
+        //  0 1 2 3 ^ 5
+        assert_eq!(map.find_offset(four), Err(1));
+        // |#|#|#|#|_|_|_|_|_|...
+        //  0 1 2 3 ^ ^ ^ ^ 8
+        assert_eq!(map.access_type(alloc_range(four, four)), AccessType::Empty(1));
+
+        let eight = Size::from_bytes(8);
+        // |#|#|#|#|_|_|_|_|@|@|@|@|_|_|...
+        //  0 1 2 3 4 5 6 7 8 9 a b c d
+        map.insert_at_pos(1, alloc_range(eight, four), "@");
+        // |#|#|#|#|_|_|_|_|@|@|@|@|_|_|...
+        //  0 1 2 3 4 5 6 ^ 8 9 a b c d
+        assert_eq!(map.find_offset(Size::from_bytes(7)), Err(1));
+        // |#|#|#|#|_|_|_|_|@|@|@|@|_|_|...
+        //  0 1 2 3 ^ ^ ^ ^ 8 9 a b c d
+        assert_eq!(map.access_type(alloc_range(four, four)), AccessType::Empty(1));
+    }
+
+    #[test]
+    fn perfectly_overlapping() {
+        let four = Size::from_bytes(4);
+
+        let mut map = RangeObjectMap::<&str>::new();
+
+        // |#|#|#|#|_|_|...
+        //  0 1 2 3 4 5
+        map.insert_at_pos(0, alloc_range(Size::ZERO, four), "#");
+        // |#|#|#|#|_|_|...
+        //  ^ ^ ^ ^ 4 5
+        assert_eq!(map.find_offset(Size::ZERO), Ok(0));
+        assert_eq!(
+            map.access_type(alloc_range(Size::ZERO, four)),
+            AccessType::PerfectlyOverlapping(0)
+        );
+
+        // |#|#|#|#|@|@|@|@|_|...
+        //  0 1 2 3 4 5 6 7 8
+        map.insert_at_pos(1, alloc_range(four, four), "@");
+        // |#|#|#|#|@|@|@|@|_|...
+        //  0 1 2 3 ^ ^ ^ ^ 8
+        assert_eq!(map.find_offset(four), Ok(1));
+        assert_eq!(map.access_type(alloc_range(four, four)), AccessType::PerfectlyOverlapping(1));
+    }
+
+    #[test]
+    fn straddling() {
+        let four = Size::from_bytes(4);
+
+        let mut map = RangeObjectMap::<&str>::new();
+
+        // |_|_|_|_|#|#|#|#|_|_|_|_|...
+        //  0 1 2 3 4 5 6 7 8 9 a b c d
+        map.insert_at_pos(0, alloc_range(four, four), "#");
+        // |_|_|_|_|#|#|#|#|_|_|_|_|...
+        //  0 1 ^ ^ ^ ^ 6 7 8 9 a b c d
+        assert_eq!(
+            map.access_type(alloc_range(Size::from_bytes(2), four)),
+            AccessType::ImperfectlyOverlapping(0..1)
+        );
+        // |_|_|_|_|#|#|#|#|_|_|_|_|...
+        //  0 1 2 3 4 5 ^ ^ ^ ^ a b c d
+        assert_eq!(
+            map.access_type(alloc_range(Size::from_bytes(6), four)),
+            AccessType::ImperfectlyOverlapping(0..1)
+        );
+        // |_|_|_|_|#|#|#|#|_|_|_|_|...
+        //  0 1 ^ ^ ^ ^ ^ ^ ^ ^ a b c d
+        assert_eq!(
+            map.access_type(alloc_range(Size::from_bytes(2), Size::from_bytes(8))),
+            AccessType::ImperfectlyOverlapping(0..1)
+        );
+
+        // |_|_|_|_|#|#|#|#|_|_|@|@|_|_|...
+        //  0 1 2 3 4 5 6 7 8 9 a b c d
+        map.insert_at_pos(1, alloc_range(Size::from_bytes(10), Size::from_bytes(2)), "@");
+        // |_|_|_|_|#|#|#|#|_|_|@|@|_|_|...
+        //  0 1 2 3 4 5 ^ ^ ^ ^ ^ ^ ^ ^
+        assert_eq!(
+            map.access_type(alloc_range(Size::from_bytes(6), Size::from_bytes(8))),
+            AccessType::ImperfectlyOverlapping(0..2)
+        );
+    }
+}
diff --git a/src/tools/miri/src/concurrency/sync.rs b/src/tools/miri/src/concurrency/sync.rs
new file mode 100644
index 000000000000..464f452ca769
--- /dev/null
+++ b/src/tools/miri/src/concurrency/sync.rs
@@ -0,0 +1,584 @@
+use std::collections::{hash_map::Entry, VecDeque};
+use std::num::NonZeroU32;
+use std::ops::Not;
+
+use log::trace;
+
+use rustc_data_structures::fx::FxHashMap;
+use rustc_index::vec::{Idx, IndexVec};
+
+use super::vector_clock::VClock;
+use crate::*;
+
+/// We cannot use the `newtype_index!` macro because we have to use 0 as a
+/// sentinel value meaning that the identifier is not assigned. This is because
+/// the pthreads static initializers initialize memory with zeros (see the
+/// `src/shims/sync.rs` file).
+macro_rules! declare_id {
+    ($name: ident) => {
+        /// 0 is used to indicate that the id was not yet assigned and,
+        /// therefore, is not a valid identifier.
+        #[derive(Clone, Copy, Debug, PartialOrd, Ord, PartialEq, Eq, Hash)]
+        pub struct $name(NonZeroU32);
+
+        impl $name {
+            // Panics if `id == 0`.
+            pub fn from_u32(id: u32) -> Self {
+                Self(NonZeroU32::new(id).unwrap())
+            }
+        }
+
+        impl Idx for $name {
+            fn new(idx: usize) -> Self {
+                // We use 0 as a sentinel value (see the comment above) and,
+                // therefore, need to shift by one when converting from an index
+                // into a vector.
+                let shifted_idx = u32::try_from(idx).unwrap().checked_add(1).unwrap();
+                $name(NonZeroU32::new(shifted_idx).unwrap())
+            }
+            fn index(self) -> usize {
+                // See the comment in `Self::new`.
+                // (This cannot underflow because self is NonZeroU32.)
+                usize::try_from(self.0.get() - 1).unwrap()
+            }
+        }
+
+        impl $name {
+            pub fn to_u32_scalar(&self) -> Scalar<Provenance> {
+                Scalar::from_u32(self.0.get())
+            }
+        }
+    };
+}
+
+declare_id!(MutexId);
+
+/// The mutex state.
+#[derive(Default, Debug)]
+struct Mutex {
+    /// The thread that currently owns the lock.
+    owner: Option<ThreadId>,
+    /// How many times the mutex was locked by the owner.
+    lock_count: usize,
+    /// The queue of threads waiting for this mutex.
+    queue: VecDeque<ThreadId>,
+    /// Data race handle, this tracks the happens-before
+    /// relationship between each mutex access. It is
+    /// released to during unlock and acquired from during
+    /// locking, and therefore stores the clock of the last
+    /// thread to release this mutex.
+    data_race: VClock,
+}
+
+declare_id!(RwLockId);
+
+/// The read-write lock state.
+#[derive(Default, Debug)]
+struct RwLock {
+    /// The writer thread that currently owns the lock.
+    writer: Option<ThreadId>,
+    /// The readers that currently own the lock and how many times they acquired
+    /// the lock.
+    readers: FxHashMap<ThreadId, usize>,
+    /// The queue of writer threads waiting for this lock.
+    writer_queue: VecDeque<ThreadId>,
+    /// The queue of reader threads waiting for this lock.
+    reader_queue: VecDeque<ThreadId>,
+    /// Data race handle for writers, tracks the happens-before
+    /// ordering between each write access to a rwlock and is updated
+    /// after a sequence of concurrent readers to track the happens-
+    /// before ordering between the set of previous readers and
+    /// the current writer.
+    /// Contains the clock of the last thread to release a writer
+    /// lock or the joined clock of the set of last threads to release
+    /// shared reader locks.
+    data_race: VClock,
+    /// Data race handle for readers, this is temporary storage
+    /// for the combined happens-before ordering for between all
+    /// concurrent readers and the next writer, and the value
+    /// is stored to the main data_race variable once all
+    /// readers are finished.
+    /// Has to be stored separately since reader lock acquires
+    /// must load the clock of the last write and must not
+    /// add happens-before orderings between shared reader
+    /// locks.
+    data_race_reader: VClock,
+}
+
+declare_id!(CondvarId);
+
+/// A thread waiting on a conditional variable.
+#[derive(Debug)]
+struct CondvarWaiter {
+    /// The thread that is waiting on this variable.
+    thread: ThreadId,
+    /// The mutex on which the thread is waiting.
+    mutex: MutexId,
+}
+
+/// The conditional variable state.
+#[derive(Default, Debug)]
+struct Condvar {
+    waiters: VecDeque<CondvarWaiter>,
+    /// Tracks the happens-before relationship
+    /// between a cond-var signal and a cond-var
+    /// wait during a non-suprious signal event.
+    /// Contains the clock of the last thread to
+    /// perform a futex-signal.
+    data_race: VClock,
+}
+
+/// The futex state.
+#[derive(Default, Debug)]
+struct Futex {
+    waiters: VecDeque<FutexWaiter>,
+    /// Tracks the happens-before relationship
+    /// between a futex-wake and a futex-wait
+    /// during a non-spurious wake event.
+    /// Contains the clock of the last thread to
+    /// perform a futex-wake.
+    data_race: VClock,
+}
+
+/// A thread waiting on a futex.
+#[derive(Debug)]
+struct FutexWaiter {
+    /// The thread that is waiting on this futex.
+    thread: ThreadId,
+    /// The bitset used by FUTEX_*_BITSET, or u32::MAX for other operations.
+    bitset: u32,
+}
+
+/// The state of all synchronization variables.
+#[derive(Default, Debug)]
+pub(crate) struct SynchronizationState {
+    mutexes: IndexVec<MutexId, Mutex>,
+    rwlocks: IndexVec<RwLockId, RwLock>,
+    condvars: IndexVec<CondvarId, Condvar>,
+    futexes: FxHashMap<u64, Futex>,
+}
+
+// Private extension trait for local helper methods
+impl<'mir, 'tcx: 'mir> EvalContextExtPriv<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+trait EvalContextExtPriv<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Take a reader out of the queue waiting for the lock.
+    /// Returns `true` if some thread got the rwlock.
+    #[inline]
+    fn rwlock_dequeue_and_lock_reader(&mut self, id: RwLockId) -> bool {
+        let this = self.eval_context_mut();
+        if let Some(reader) = this.machine.threads.sync.rwlocks[id].reader_queue.pop_front() {
+            this.unblock_thread(reader);
+            this.rwlock_reader_lock(id, reader);
+            true
+        } else {
+            false
+        }
+    }
+
+    /// Take the writer out of the queue waiting for the lock.
+    /// Returns `true` if some thread got the rwlock.
+    #[inline]
+    fn rwlock_dequeue_and_lock_writer(&mut self, id: RwLockId) -> bool {
+        let this = self.eval_context_mut();
+        if let Some(writer) = this.machine.threads.sync.rwlocks[id].writer_queue.pop_front() {
+            this.unblock_thread(writer);
+            this.rwlock_writer_lock(id, writer);
+            true
+        } else {
+            false
+        }
+    }
+
+    /// Take a thread out of the queue waiting for the mutex, and lock
+    /// the mutex for it. Returns `true` if some thread has the mutex now.
+    #[inline]
+    fn mutex_dequeue_and_lock(&mut self, id: MutexId) -> bool {
+        let this = self.eval_context_mut();
+        if let Some(thread) = this.machine.threads.sync.mutexes[id].queue.pop_front() {
+            this.unblock_thread(thread);
+            this.mutex_lock(id, thread);
+            true
+        } else {
+            false
+        }
+    }
+}
+
+// Public interface to synchronization primitives. Please note that in most
+// cases, the function calls are infallible and it is the client's (shim
+// implementation's) responsibility to detect and deal with erroneous
+// situations.
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    #[inline]
+    /// Create state for a new mutex.
+    fn mutex_create(&mut self) -> MutexId {
+        let this = self.eval_context_mut();
+        this.machine.threads.sync.mutexes.push(Default::default())
+    }
+
+    #[inline]
+    /// Provides the closure with the next MutexId. Creates that mutex if the closure returns None,
+    /// otherwise returns the value from the closure
+    fn mutex_get_or_create<F>(&mut self, existing: F) -> InterpResult<'tcx, MutexId>
+    where
+        F: FnOnce(&mut MiriInterpCx<'mir, 'tcx>, MutexId) -> InterpResult<'tcx, Option<MutexId>>,
+    {
+        let this = self.eval_context_mut();
+        let next_index = this.machine.threads.sync.mutexes.next_index();
+        if let Some(old) = existing(this, next_index)? {
+            Ok(old)
+        } else {
+            let new_index = this.machine.threads.sync.mutexes.push(Default::default());
+            assert_eq!(next_index, new_index);
+            Ok(new_index)
+        }
+    }
+
+    #[inline]
+    /// Get the id of the thread that currently owns this lock.
+    fn mutex_get_owner(&mut self, id: MutexId) -> ThreadId {
+        let this = self.eval_context_ref();
+        this.machine.threads.sync.mutexes[id].owner.unwrap()
+    }
+
+    #[inline]
+    /// Check if locked.
+    fn mutex_is_locked(&self, id: MutexId) -> bool {
+        let this = self.eval_context_ref();
+        this.machine.threads.sync.mutexes[id].owner.is_some()
+    }
+
+    /// Lock by setting the mutex owner and increasing the lock count.
+    fn mutex_lock(&mut self, id: MutexId, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        let mutex = &mut this.machine.threads.sync.mutexes[id];
+        if let Some(current_owner) = mutex.owner {
+            assert_eq!(thread, current_owner, "mutex already locked by another thread");
+            assert!(
+                mutex.lock_count > 0,
+                "invariant violation: lock_count == 0 iff the thread is unlocked"
+            );
+        } else {
+            mutex.owner = Some(thread);
+        }
+        mutex.lock_count = mutex.lock_count.checked_add(1).unwrap();
+        if let Some(data_race) = &this.machine.data_race {
+            data_race.validate_lock_acquire(&mutex.data_race, thread);
+        }
+    }
+
+    /// Try unlocking by decreasing the lock count and returning the old lock
+    /// count. If the lock count reaches 0, release the lock and potentially
+    /// give to a new owner. If the lock was not locked by `expected_owner`,
+    /// return `None`.
+    fn mutex_unlock(&mut self, id: MutexId, expected_owner: ThreadId) -> Option<usize> {
+        let this = self.eval_context_mut();
+        let mutex = &mut this.machine.threads.sync.mutexes[id];
+        if let Some(current_owner) = mutex.owner {
+            // Mutex is locked.
+            if current_owner != expected_owner {
+                // Only the owner can unlock the mutex.
+                return None;
+            }
+            let old_lock_count = mutex.lock_count;
+            mutex.lock_count = old_lock_count
+                .checked_sub(1)
+                .expect("invariant violation: lock_count == 0 iff the thread is unlocked");
+            if mutex.lock_count == 0 {
+                mutex.owner = None;
+                // The mutex is completely unlocked. Try transfering ownership
+                // to another thread.
+                if let Some(data_race) = &this.machine.data_race {
+                    data_race.validate_lock_release(&mut mutex.data_race, current_owner);
+                }
+                this.mutex_dequeue_and_lock(id);
+            }
+            Some(old_lock_count)
+        } else {
+            // Mutex is not locked.
+            None
+        }
+    }
+
+    #[inline]
+    /// Put the thread into the queue waiting for the mutex.
+    fn mutex_enqueue_and_block(&mut self, id: MutexId, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        assert!(this.mutex_is_locked(id), "queing on unlocked mutex");
+        this.machine.threads.sync.mutexes[id].queue.push_back(thread);
+        this.block_thread(thread);
+    }
+
+    #[inline]
+    /// Create state for a new read write lock.
+    fn rwlock_create(&mut self) -> RwLockId {
+        let this = self.eval_context_mut();
+        this.machine.threads.sync.rwlocks.push(Default::default())
+    }
+
+    #[inline]
+    /// Provides the closure with the next RwLockId. Creates that RwLock if the closure returns None,
+    /// otherwise returns the value from the closure
+    fn rwlock_get_or_create<F>(&mut self, existing: F) -> InterpResult<'tcx, RwLockId>
+    where
+        F: FnOnce(&mut MiriInterpCx<'mir, 'tcx>, RwLockId) -> InterpResult<'tcx, Option<RwLockId>>,
+    {
+        let this = self.eval_context_mut();
+        let next_index = this.machine.threads.sync.rwlocks.next_index();
+        if let Some(old) = existing(this, next_index)? {
+            Ok(old)
+        } else {
+            let new_index = this.machine.threads.sync.rwlocks.push(Default::default());
+            assert_eq!(next_index, new_index);
+            Ok(new_index)
+        }
+    }
+
+    #[inline]
+    /// Check if locked.
+    fn rwlock_is_locked(&self, id: RwLockId) -> bool {
+        let this = self.eval_context_ref();
+        let rwlock = &this.machine.threads.sync.rwlocks[id];
+        trace!(
+            "rwlock_is_locked: {:?} writer is {:?} and there are {} reader threads (some of which could hold multiple read locks)",
+            id,
+            rwlock.writer,
+            rwlock.readers.len(),
+        );
+        rwlock.writer.is_some() || rwlock.readers.is_empty().not()
+    }
+
+    #[inline]
+    /// Check if write locked.
+    fn rwlock_is_write_locked(&self, id: RwLockId) -> bool {
+        let this = self.eval_context_ref();
+        let rwlock = &this.machine.threads.sync.rwlocks[id];
+        trace!("rwlock_is_write_locked: {:?} writer is {:?}", id, rwlock.writer);
+        rwlock.writer.is_some()
+    }
+
+    /// Read-lock the lock by adding the `reader` the list of threads that own
+    /// this lock.
+    fn rwlock_reader_lock(&mut self, id: RwLockId, reader: ThreadId) {
+        let this = self.eval_context_mut();
+        assert!(!this.rwlock_is_write_locked(id), "the lock is write locked");
+        trace!("rwlock_reader_lock: {:?} now also held (one more time) by {:?}", id, reader);
+        let rwlock = &mut this.machine.threads.sync.rwlocks[id];
+        let count = rwlock.readers.entry(reader).or_insert(0);
+        *count = count.checked_add(1).expect("the reader counter overflowed");
+        if let Some(data_race) = &this.machine.data_race {
+            data_race.validate_lock_acquire(&rwlock.data_race, reader);
+        }
+    }
+
+    /// Try read-unlock the lock for `reader` and potentially give the lock to a new owner.
+    /// Returns `true` if succeeded, `false` if this `reader` did not hold the lock.
+    fn rwlock_reader_unlock(&mut self, id: RwLockId, reader: ThreadId) -> bool {
+        let this = self.eval_context_mut();
+        let rwlock = &mut this.machine.threads.sync.rwlocks[id];
+        match rwlock.readers.entry(reader) {
+            Entry::Occupied(mut entry) => {
+                let count = entry.get_mut();
+                assert!(*count > 0, "rwlock locked with count == 0");
+                *count -= 1;
+                if *count == 0 {
+                    trace!("rwlock_reader_unlock: {:?} no longer held by {:?}", id, reader);
+                    entry.remove();
+                } else {
+                    trace!("rwlock_reader_unlock: {:?} held one less time by {:?}", id, reader);
+                }
+            }
+            Entry::Vacant(_) => return false, // we did not even own this lock
+        }
+        if let Some(data_race) = &this.machine.data_race {
+            data_race.validate_lock_release_shared(&mut rwlock.data_race_reader, reader);
+        }
+
+        // The thread was a reader. If the lock is not held any more, give it to a writer.
+        if this.rwlock_is_locked(id).not() {
+            // All the readers are finished, so set the writer data-race handle to the value
+            //  of the union of all reader data race handles, since the set of readers
+            //  happen-before the writers
+            let rwlock = &mut this.machine.threads.sync.rwlocks[id];
+            rwlock.data_race.clone_from(&rwlock.data_race_reader);
+            this.rwlock_dequeue_and_lock_writer(id);
+        }
+        true
+    }
+
+    #[inline]
+    /// Put the reader in the queue waiting for the lock and block it.
+    fn rwlock_enqueue_and_block_reader(&mut self, id: RwLockId, reader: ThreadId) {
+        let this = self.eval_context_mut();
+        assert!(this.rwlock_is_write_locked(id), "read-queueing on not write locked rwlock");
+        this.machine.threads.sync.rwlocks[id].reader_queue.push_back(reader);
+        this.block_thread(reader);
+    }
+
+    #[inline]
+    /// Lock by setting the writer that owns the lock.
+    fn rwlock_writer_lock(&mut self, id: RwLockId, writer: ThreadId) {
+        let this = self.eval_context_mut();
+        assert!(!this.rwlock_is_locked(id), "the rwlock is already locked");
+        trace!("rwlock_writer_lock: {:?} now held by {:?}", id, writer);
+        let rwlock = &mut this.machine.threads.sync.rwlocks[id];
+        rwlock.writer = Some(writer);
+        if let Some(data_race) = &this.machine.data_race {
+            data_race.validate_lock_acquire(&rwlock.data_race, writer);
+        }
+    }
+
+    #[inline]
+    /// Try to unlock by removing the writer.
+    fn rwlock_writer_unlock(&mut self, id: RwLockId, expected_writer: ThreadId) -> bool {
+        let this = self.eval_context_mut();
+        let rwlock = &mut this.machine.threads.sync.rwlocks[id];
+        if let Some(current_writer) = rwlock.writer {
+            if current_writer != expected_writer {
+                // Only the owner can unlock the rwlock.
+                return false;
+            }
+            rwlock.writer = None;
+            trace!("rwlock_writer_unlock: {:?} unlocked by {:?}", id, expected_writer);
+            // Release memory to both reader and writer vector clocks
+            //  since this writer happens-before both the union of readers once they are finished
+            //  and the next writer
+            if let Some(data_race) = &this.machine.data_race {
+                data_race.validate_lock_release(&mut rwlock.data_race, current_writer);
+                data_race.validate_lock_release(&mut rwlock.data_race_reader, current_writer);
+            }
+            // The thread was a writer.
+            //
+            // We are prioritizing writers here against the readers. As a
+            // result, not only readers can starve writers, but also writers can
+            // starve readers.
+            if this.rwlock_dequeue_and_lock_writer(id) {
+                // Someone got the write lock, nice.
+            } else {
+                // Give the lock to all readers.
+                while this.rwlock_dequeue_and_lock_reader(id) {
+                    // Rinse and repeat.
+                }
+            }
+            true
+        } else {
+            false
+        }
+    }
+
+    #[inline]
+    /// Put the writer in the queue waiting for the lock.
+    fn rwlock_enqueue_and_block_writer(&mut self, id: RwLockId, writer: ThreadId) {
+        let this = self.eval_context_mut();
+        assert!(this.rwlock_is_locked(id), "write-queueing on unlocked rwlock");
+        this.machine.threads.sync.rwlocks[id].writer_queue.push_back(writer);
+        this.block_thread(writer);
+    }
+
+    #[inline]
+    /// Create state for a new conditional variable.
+    fn condvar_create(&mut self) -> CondvarId {
+        let this = self.eval_context_mut();
+        this.machine.threads.sync.condvars.push(Default::default())
+    }
+
+    #[inline]
+    /// Provides the closure with the next CondvarId. Creates that Condvar if the closure returns None,
+    /// otherwise returns the value from the closure
+    fn condvar_get_or_create<F>(&mut self, existing: F) -> InterpResult<'tcx, CondvarId>
+    where
+        F: FnOnce(
+            &mut MiriInterpCx<'mir, 'tcx>,
+            CondvarId,
+        ) -> InterpResult<'tcx, Option<CondvarId>>,
+    {
+        let this = self.eval_context_mut();
+        let next_index = this.machine.threads.sync.condvars.next_index();
+        if let Some(old) = existing(this, next_index)? {
+            Ok(old)
+        } else {
+            let new_index = this.machine.threads.sync.condvars.push(Default::default());
+            assert_eq!(next_index, new_index);
+            Ok(new_index)
+        }
+    }
+
+    #[inline]
+    /// Is the conditional variable awaited?
+    fn condvar_is_awaited(&mut self, id: CondvarId) -> bool {
+        let this = self.eval_context_mut();
+        !this.machine.threads.sync.condvars[id].waiters.is_empty()
+    }
+
+    /// Mark that the thread is waiting on the conditional variable.
+    fn condvar_wait(&mut self, id: CondvarId, thread: ThreadId, mutex: MutexId) {
+        let this = self.eval_context_mut();
+        let waiters = &mut this.machine.threads.sync.condvars[id].waiters;
+        assert!(waiters.iter().all(|waiter| waiter.thread != thread), "thread is already waiting");
+        waiters.push_back(CondvarWaiter { thread, mutex });
+    }
+
+    /// Wake up some thread (if there is any) sleeping on the conditional
+    /// variable.
+    fn condvar_signal(&mut self, id: CondvarId) -> Option<(ThreadId, MutexId)> {
+        let this = self.eval_context_mut();
+        let current_thread = this.get_active_thread();
+        let condvar = &mut this.machine.threads.sync.condvars[id];
+        let data_race = &this.machine.data_race;
+
+        // Each condvar signal happens-before the end of the condvar wake
+        if let Some(data_race) = data_race {
+            data_race.validate_lock_release(&mut condvar.data_race, current_thread);
+        }
+        condvar.waiters.pop_front().map(|waiter| {
+            if let Some(data_race) = data_race {
+                data_race.validate_lock_acquire(&condvar.data_race, waiter.thread);
+            }
+            (waiter.thread, waiter.mutex)
+        })
+    }
+
+    #[inline]
+    /// Remove the thread from the queue of threads waiting on this conditional variable.
+    fn condvar_remove_waiter(&mut self, id: CondvarId, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        this.machine.threads.sync.condvars[id].waiters.retain(|waiter| waiter.thread != thread);
+    }
+
+    fn futex_wait(&mut self, addr: u64, thread: ThreadId, bitset: u32) {
+        let this = self.eval_context_mut();
+        let futex = &mut this.machine.threads.sync.futexes.entry(addr).or_default();
+        let waiters = &mut futex.waiters;
+        assert!(waiters.iter().all(|waiter| waiter.thread != thread), "thread is already waiting");
+        waiters.push_back(FutexWaiter { thread, bitset });
+    }
+
+    fn futex_wake(&mut self, addr: u64, bitset: u32) -> Option<ThreadId> {
+        let this = self.eval_context_mut();
+        let current_thread = this.get_active_thread();
+        let futex = &mut this.machine.threads.sync.futexes.get_mut(&addr)?;
+        let data_race = &this.machine.data_race;
+
+        // Each futex-wake happens-before the end of the futex wait
+        if let Some(data_race) = data_race {
+            data_race.validate_lock_release(&mut futex.data_race, current_thread);
+        }
+
+        // Wake up the first thread in the queue that matches any of the bits in the bitset.
+        futex.waiters.iter().position(|w| w.bitset & bitset != 0).map(|i| {
+            let waiter = futex.waiters.remove(i).unwrap();
+            if let Some(data_race) = data_race {
+                data_race.validate_lock_acquire(&futex.data_race, waiter.thread);
+            }
+            waiter.thread
+        })
+    }
+
+    fn futex_remove_waiter(&mut self, addr: u64, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        if let Some(futex) = this.machine.threads.sync.futexes.get_mut(&addr) {
+            futex.waiters.retain(|waiter| waiter.thread != thread);
+        }
+    }
+}
diff --git a/src/tools/miri/src/concurrency/thread.rs b/src/tools/miri/src/concurrency/thread.rs
new file mode 100644
index 000000000000..f1a3d19fb4cb
--- /dev/null
+++ b/src/tools/miri/src/concurrency/thread.rs
@@ -0,0 +1,933 @@
+//! Implements threads.
+
+use std::cell::RefCell;
+use std::collections::hash_map::Entry;
+use std::num::TryFromIntError;
+use std::time::{Duration, SystemTime};
+
+use log::trace;
+
+use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::def_id::DefId;
+use rustc_index::vec::{Idx, IndexVec};
+use rustc_middle::mir::Mutability;
+use rustc_middle::ty::layout::TyAndLayout;
+use rustc_target::spec::abi::Abi;
+
+use crate::concurrency::data_race;
+use crate::concurrency::sync::SynchronizationState;
+use crate::*;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum SchedulingAction {
+    /// Execute step on the active thread.
+    ExecuteStep,
+    /// Execute a timeout callback.
+    ExecuteTimeoutCallback,
+    /// Execute destructors of the active thread.
+    ExecuteDtors,
+    /// Stop the program.
+    Stop,
+}
+
+/// Timeout callbacks can be created by synchronization primitives to tell the
+/// scheduler that they should be called once some period of time passes.
+type TimeoutCallback<'mir, 'tcx> = Box<
+    dyn FnOnce(&mut InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>) -> InterpResult<'tcx> + 'tcx,
+>;
+
+/// A thread identifier.
+#[derive(Clone, Copy, Debug, PartialOrd, Ord, PartialEq, Eq, Hash)]
+pub struct ThreadId(u32);
+
+/// The main thread. When it terminates, the whole application terminates.
+const MAIN_THREAD: ThreadId = ThreadId(0);
+
+impl ThreadId {
+    pub fn to_u32(self) -> u32 {
+        self.0
+    }
+}
+
+impl Idx for ThreadId {
+    fn new(idx: usize) -> Self {
+        ThreadId(u32::try_from(idx).unwrap())
+    }
+
+    fn index(self) -> usize {
+        usize::try_from(self.0).unwrap()
+    }
+}
+
+impl TryFrom<u64> for ThreadId {
+    type Error = TryFromIntError;
+    fn try_from(id: u64) -> Result<Self, Self::Error> {
+        u32::try_from(id).map(Self)
+    }
+}
+
+impl From<u32> for ThreadId {
+    fn from(id: u32) -> Self {
+        Self(id)
+    }
+}
+
+impl From<ThreadId> for u64 {
+    fn from(t: ThreadId) -> Self {
+        t.0.into()
+    }
+}
+
+/// The state of a thread.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum ThreadState {
+    /// The thread is enabled and can be executed.
+    Enabled,
+    /// The thread tried to join the specified thread and is blocked until that
+    /// thread terminates.
+    BlockedOnJoin(ThreadId),
+    /// The thread is blocked on some synchronization primitive. It is the
+    /// responsibility of the synchronization primitives to track threads that
+    /// are blocked by them.
+    BlockedOnSync,
+    /// The thread has terminated its execution. We do not delete terminated
+    /// threads (FIXME: why?).
+    Terminated,
+}
+
+/// The join status of a thread.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+enum ThreadJoinStatus {
+    /// The thread can be joined.
+    Joinable,
+    /// A thread is detached if its join handle was destroyed and no other
+    /// thread can join it.
+    Detached,
+    /// The thread was already joined by some thread and cannot be joined again.
+    Joined,
+}
+
+/// A thread.
+pub struct Thread<'mir, 'tcx> {
+    state: ThreadState,
+
+    /// Name of the thread.
+    thread_name: Option<Vec<u8>>,
+
+    /// The virtual call stack.
+    stack: Vec<Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>>,
+
+    /// The join status.
+    join_status: ThreadJoinStatus,
+
+    /// The temporary used for storing the argument of
+    /// the call to `miri_start_panic` (the panic payload) when unwinding.
+    /// This is pointer-sized, and matches the `Payload` type in `src/libpanic_unwind/miri.rs`.
+    pub(crate) panic_payload: Option<Scalar<Provenance>>,
+
+    /// Last OS error location in memory. It is a 32-bit integer.
+    pub(crate) last_error: Option<MPlaceTy<'tcx, Provenance>>,
+}
+
+impl<'mir, 'tcx> Thread<'mir, 'tcx> {
+    /// Check if the thread is done executing (no more stack frames). If yes,
+    /// change the state to terminated and return `true`.
+    fn check_terminated(&mut self) -> bool {
+        if self.state == ThreadState::Enabled {
+            if self.stack.is_empty() {
+                self.state = ThreadState::Terminated;
+                return true;
+            }
+        }
+        false
+    }
+
+    /// Get the name of the current thread, or `<unnamed>` if it was not set.
+    fn thread_name(&self) -> &[u8] {
+        if let Some(ref thread_name) = self.thread_name { thread_name } else { b"<unnamed>" }
+    }
+}
+
+impl<'mir, 'tcx> std::fmt::Debug for Thread<'mir, 'tcx> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}({:?}, {:?})",
+            String::from_utf8_lossy(self.thread_name()),
+            self.state,
+            self.join_status
+        )
+    }
+}
+
+impl<'mir, 'tcx> Default for Thread<'mir, 'tcx> {
+    fn default() -> Self {
+        Self {
+            state: ThreadState::Enabled,
+            thread_name: None,
+            stack: Vec::new(),
+            join_status: ThreadJoinStatus::Joinable,
+            panic_payload: None,
+            last_error: None,
+        }
+    }
+}
+
+impl<'mir, 'tcx> Thread<'mir, 'tcx> {
+    fn new(name: &str) -> Self {
+        let mut thread = Thread::default();
+        thread.thread_name = Some(Vec::from(name.as_bytes()));
+        thread
+    }
+}
+
+/// A specific moment in time.
+#[derive(Debug)]
+pub enum Time {
+    Monotonic(Instant),
+    RealTime(SystemTime),
+}
+
+impl Time {
+    /// How long do we have to wait from now until the specified time?
+    fn get_wait_time(&self, clock: &Clock) -> Duration {
+        match self {
+            Time::Monotonic(instant) => instant.duration_since(clock.now()),
+            Time::RealTime(time) =>
+                time.duration_since(SystemTime::now()).unwrap_or(Duration::new(0, 0)),
+        }
+    }
+}
+
+/// Callbacks are used to implement timeouts. For example, waiting on a
+/// conditional variable with a timeout creates a callback that is called after
+/// the specified time and unblocks the thread. If another thread signals on the
+/// conditional variable, the signal handler deletes the callback.
+struct TimeoutCallbackInfo<'mir, 'tcx> {
+    /// The callback should be called no earlier than this time.
+    call_time: Time,
+    /// The called function.
+    callback: TimeoutCallback<'mir, 'tcx>,
+}
+
+impl<'mir, 'tcx> std::fmt::Debug for TimeoutCallbackInfo<'mir, 'tcx> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "TimeoutCallback({:?})", self.call_time)
+    }
+}
+
+/// A set of threads.
+#[derive(Debug)]
+pub struct ThreadManager<'mir, 'tcx> {
+    /// Identifier of the currently active thread.
+    active_thread: ThreadId,
+    /// Threads used in the program.
+    ///
+    /// Note that this vector also contains terminated threads.
+    threads: IndexVec<ThreadId, Thread<'mir, 'tcx>>,
+    /// This field is pub(crate) because the synchronization primitives
+    /// (`crate::sync`) need a way to access it.
+    pub(crate) sync: SynchronizationState,
+    /// A mapping from a thread-local static to an allocation id of a thread
+    /// specific allocation.
+    thread_local_alloc_ids: RefCell<FxHashMap<(DefId, ThreadId), Pointer<Provenance>>>,
+    /// A flag that indicates that we should change the active thread.
+    yield_active_thread: bool,
+    /// Callbacks that are called once the specified time passes.
+    timeout_callbacks: FxHashMap<ThreadId, TimeoutCallbackInfo<'mir, 'tcx>>,
+}
+
+impl<'mir, 'tcx> Default for ThreadManager<'mir, 'tcx> {
+    fn default() -> Self {
+        let mut threads = IndexVec::new();
+        // Create the main thread and add it to the list of threads.
+        threads.push(Thread::new("main"));
+        Self {
+            active_thread: ThreadId::new(0),
+            threads,
+            sync: SynchronizationState::default(),
+            thread_local_alloc_ids: Default::default(),
+            yield_active_thread: false,
+            timeout_callbacks: FxHashMap::default(),
+        }
+    }
+}
+
+impl<'mir, 'tcx: 'mir> ThreadManager<'mir, 'tcx> {
+    pub(crate) fn init(ecx: &mut MiriInterpCx<'mir, 'tcx>) {
+        if ecx.tcx.sess.target.os.as_ref() != "windows" {
+            // The main thread can *not* be joined on except on windows.
+            ecx.machine.threads.threads[ThreadId::new(0)].join_status = ThreadJoinStatus::Detached;
+        }
+    }
+
+    /// Check if we have an allocation for the given thread local static for the
+    /// active thread.
+    fn get_thread_local_alloc_id(&self, def_id: DefId) -> Option<Pointer<Provenance>> {
+        self.thread_local_alloc_ids.borrow().get(&(def_id, self.active_thread)).cloned()
+    }
+
+    /// Set the pointer for the allocation of the given thread local
+    /// static for the active thread.
+    ///
+    /// Panics if a thread local is initialized twice for the same thread.
+    fn set_thread_local_alloc(&self, def_id: DefId, ptr: Pointer<Provenance>) {
+        self.thread_local_alloc_ids
+            .borrow_mut()
+            .try_insert((def_id, self.active_thread), ptr)
+            .unwrap();
+    }
+
+    /// Borrow the stack of the active thread.
+    pub fn active_thread_stack(&self) -> &[Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>] {
+        &self.threads[self.active_thread].stack
+    }
+
+    /// Mutably borrow the stack of the active thread.
+    fn active_thread_stack_mut(
+        &mut self,
+    ) -> &mut Vec<Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>> {
+        &mut self.threads[self.active_thread].stack
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &Thread<'mir, 'tcx>> {
+        self.threads.iter()
+    }
+
+    pub fn all_stacks(
+        &self,
+    ) -> impl Iterator<Item = &[Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>]> {
+        self.threads.iter().map(|t| &t.stack[..])
+    }
+
+    /// Create a new thread and returns its id.
+    fn create_thread(&mut self) -> ThreadId {
+        let new_thread_id = ThreadId::new(self.threads.len());
+        self.threads.push(Default::default());
+        new_thread_id
+    }
+
+    /// Set an active thread and return the id of the thread that was active before.
+    fn set_active_thread_id(&mut self, id: ThreadId) -> ThreadId {
+        let active_thread_id = self.active_thread;
+        self.active_thread = id;
+        assert!(self.active_thread.index() < self.threads.len());
+        active_thread_id
+    }
+
+    /// Get the id of the currently active thread.
+    pub fn get_active_thread_id(&self) -> ThreadId {
+        self.active_thread
+    }
+
+    /// Get the total number of threads that were ever spawn by this program.
+    pub fn get_total_thread_count(&self) -> usize {
+        self.threads.len()
+    }
+
+    /// Get the total of threads that are currently live, i.e., not yet terminated.
+    /// (They might be blocked.)
+    pub fn get_live_thread_count(&self) -> usize {
+        self.threads.iter().filter(|t| !matches!(t.state, ThreadState::Terminated)).count()
+    }
+
+    /// Has the given thread terminated?
+    fn has_terminated(&self, thread_id: ThreadId) -> bool {
+        self.threads[thread_id].state == ThreadState::Terminated
+    }
+
+    /// Have all threads terminated?
+    fn have_all_terminated(&self) -> bool {
+        self.threads.iter().all(|thread| thread.state == ThreadState::Terminated)
+    }
+
+    /// Enable the thread for execution. The thread must be terminated.
+    fn enable_thread(&mut self, thread_id: ThreadId) {
+        assert!(self.has_terminated(thread_id));
+        self.threads[thread_id].state = ThreadState::Enabled;
+    }
+
+    /// Get a mutable borrow of the currently active thread.
+    fn active_thread_mut(&mut self) -> &mut Thread<'mir, 'tcx> {
+        &mut self.threads[self.active_thread]
+    }
+
+    /// Get a shared borrow of the currently active thread.
+    fn active_thread_ref(&self) -> &Thread<'mir, 'tcx> {
+        &self.threads[self.active_thread]
+    }
+
+    /// Mark the thread as detached, which means that no other thread will try
+    /// to join it and the thread is responsible for cleaning up.
+    ///
+    /// `allow_terminated_joined` allows detaching joined threads that have already terminated.
+    /// This matches Windows's behavior for `CloseHandle`.
+    ///
+    /// See <https://docs.microsoft.com/en-us/windows/win32/procthread/thread-handles-and-identifiers>:
+    /// > The handle is valid until closed, even after the thread it represents has been terminated.
+    fn detach_thread(&mut self, id: ThreadId, allow_terminated_joined: bool) -> InterpResult<'tcx> {
+        trace!("detaching {:?}", id);
+
+        let is_ub = if allow_terminated_joined && self.threads[id].state == ThreadState::Terminated
+        {
+            // "Detached" in particular means "not yet joined". Redundant detaching is still UB.
+            self.threads[id].join_status == ThreadJoinStatus::Detached
+        } else {
+            self.threads[id].join_status != ThreadJoinStatus::Joinable
+        };
+        if is_ub {
+            throw_ub_format!("trying to detach thread that was already detached or joined");
+        }
+
+        self.threads[id].join_status = ThreadJoinStatus::Detached;
+        Ok(())
+    }
+
+    /// Mark that the active thread tries to join the thread with `joined_thread_id`.
+    fn join_thread(
+        &mut self,
+        joined_thread_id: ThreadId,
+        data_race: Option<&mut data_race::GlobalState>,
+    ) -> InterpResult<'tcx> {
+        if self.threads[joined_thread_id].join_status == ThreadJoinStatus::Detached {
+            throw_ub_format!("trying to join a detached thread");
+        }
+
+        // Mark the joined thread as being joined so that we detect if other
+        // threads try to join it.
+        self.threads[joined_thread_id].join_status = ThreadJoinStatus::Joined;
+        if self.threads[joined_thread_id].state != ThreadState::Terminated {
+            // The joined thread is still running, we need to wait for it.
+            self.active_thread_mut().state = ThreadState::BlockedOnJoin(joined_thread_id);
+            trace!(
+                "{:?} blocked on {:?} when trying to join",
+                self.active_thread,
+                joined_thread_id
+            );
+        } else {
+            // The thread has already terminated - mark join happens-before
+            if let Some(data_race) = data_race {
+                data_race.thread_joined(self, self.active_thread, joined_thread_id);
+            }
+        }
+        Ok(())
+    }
+
+    /// Mark that the active thread tries to exclusively join the thread with `joined_thread_id`.
+    /// If the thread is already joined by another thread, it will throw UB
+    fn join_thread_exclusive(
+        &mut self,
+        joined_thread_id: ThreadId,
+        data_race: Option<&mut data_race::GlobalState>,
+    ) -> InterpResult<'tcx> {
+        if self.threads[joined_thread_id].join_status == ThreadJoinStatus::Joined {
+            throw_ub_format!("trying to join an already joined thread");
+        }
+
+        if joined_thread_id == self.active_thread {
+            throw_ub_format!("trying to join itself");
+        }
+
+        assert!(
+            self.threads
+                .iter()
+                .all(|thread| thread.state != ThreadState::BlockedOnJoin(joined_thread_id)),
+            "this thread already has threads waiting for its termination"
+        );
+
+        self.join_thread(joined_thread_id, data_race)
+    }
+
+    /// Set the name of the given thread.
+    pub fn set_thread_name(&mut self, thread: ThreadId, new_thread_name: Vec<u8>) {
+        self.threads[thread].thread_name = Some(new_thread_name);
+    }
+
+    /// Get the name of the given thread.
+    pub fn get_thread_name(&self, thread: ThreadId) -> &[u8] {
+        self.threads[thread].thread_name()
+    }
+
+    /// Put the thread into the blocked state.
+    fn block_thread(&mut self, thread: ThreadId) {
+        let state = &mut self.threads[thread].state;
+        assert_eq!(*state, ThreadState::Enabled);
+        *state = ThreadState::BlockedOnSync;
+    }
+
+    /// Put the blocked thread into the enabled state.
+    fn unblock_thread(&mut self, thread: ThreadId) {
+        let state = &mut self.threads[thread].state;
+        assert_eq!(*state, ThreadState::BlockedOnSync);
+        *state = ThreadState::Enabled;
+    }
+
+    /// Change the active thread to some enabled thread.
+    fn yield_active_thread(&mut self) {
+        // We do not yield immediately, as swapping out the current stack while executing a MIR statement
+        // could lead to all sorts of confusion.
+        // We should only switch stacks between steps.
+        self.yield_active_thread = true;
+    }
+
+    /// Register the given `callback` to be called once the `call_time` passes.
+    ///
+    /// The callback will be called with `thread` being the active thread, and
+    /// the callback may not change the active thread.
+    fn register_timeout_callback(
+        &mut self,
+        thread: ThreadId,
+        call_time: Time,
+        callback: TimeoutCallback<'mir, 'tcx>,
+    ) {
+        self.timeout_callbacks
+            .try_insert(thread, TimeoutCallbackInfo { call_time, callback })
+            .unwrap();
+    }
+
+    /// Unregister the callback for the `thread`.
+    fn unregister_timeout_callback_if_exists(&mut self, thread: ThreadId) {
+        self.timeout_callbacks.remove(&thread);
+    }
+
+    /// Get a callback that is ready to be called.
+    fn get_ready_callback(
+        &mut self,
+        clock: &Clock,
+    ) -> Option<(ThreadId, TimeoutCallback<'mir, 'tcx>)> {
+        // We iterate over all threads in the order of their indices because
+        // this allows us to have a deterministic scheduler.
+        for thread in self.threads.indices() {
+            match self.timeout_callbacks.entry(thread) {
+                Entry::Occupied(entry) =>
+                    if entry.get().call_time.get_wait_time(clock) == Duration::new(0, 0) {
+                        return Some((thread, entry.remove().callback));
+                    },
+                Entry::Vacant(_) => {}
+            }
+        }
+        None
+    }
+
+    /// Wakes up threads joining on the active one and deallocates thread-local statics.
+    /// The `AllocId` that can now be freed are returned.
+    fn thread_terminated(
+        &mut self,
+        mut data_race: Option<&mut data_race::GlobalState>,
+    ) -> Vec<Pointer<Provenance>> {
+        let mut free_tls_statics = Vec::new();
+        {
+            let mut thread_local_statics = self.thread_local_alloc_ids.borrow_mut();
+            thread_local_statics.retain(|&(_def_id, thread), &mut alloc_id| {
+                if thread != self.active_thread {
+                    // Keep this static around.
+                    return true;
+                }
+                // Delete this static from the map and from memory.
+                // We cannot free directly here as we cannot use `?` in this context.
+                free_tls_statics.push(alloc_id);
+                false
+            });
+        }
+        // Set the thread into a terminated state in the data-race detector.
+        if let Some(ref mut data_race) = data_race {
+            data_race.thread_terminated(self);
+        }
+        // Check if we need to unblock any threads.
+        let mut joined_threads = vec![]; // store which threads joined, we'll need it
+        for (i, thread) in self.threads.iter_enumerated_mut() {
+            if thread.state == ThreadState::BlockedOnJoin(self.active_thread) {
+                // The thread has terminated, mark happens-before edge to joining thread
+                if data_race.is_some() {
+                    joined_threads.push(i);
+                }
+                trace!("unblocking {:?} because {:?} terminated", i, self.active_thread);
+                thread.state = ThreadState::Enabled;
+            }
+        }
+        for &i in &joined_threads {
+            data_race.as_mut().unwrap().thread_joined(self, i, self.active_thread);
+        }
+        free_tls_statics
+    }
+
+    /// Decide which action to take next and on which thread.
+    ///
+    /// The currently implemented scheduling policy is the one that is commonly
+    /// used in stateless model checkers such as Loom: run the active thread as
+    /// long as we can and switch only when we have to (the active thread was
+    /// blocked, terminated, or has explicitly asked to be preempted).
+    fn schedule(&mut self, clock: &Clock) -> InterpResult<'tcx, SchedulingAction> {
+        // Check whether the thread has **just** terminated (`check_terminated`
+        // checks whether the thread has popped all its stack and if yes, sets
+        // the thread state to terminated).
+        if self.threads[self.active_thread].check_terminated() {
+            return Ok(SchedulingAction::ExecuteDtors);
+        }
+        // If we get here again and the thread is *still* terminated, there are no more dtors to run.
+        if self.threads[MAIN_THREAD].state == ThreadState::Terminated {
+            // The main thread terminated; stop the program.
+            // We do *not* run TLS dtors of remaining threads, which seems to match rustc behavior.
+            return Ok(SchedulingAction::Stop);
+        }
+        // This thread and the program can keep going.
+        if self.threads[self.active_thread].state == ThreadState::Enabled
+            && !self.yield_active_thread
+        {
+            // The currently active thread is still enabled, just continue with it.
+            return Ok(SchedulingAction::ExecuteStep);
+        }
+        // The active thread yielded. Let's see if there are any timeouts to take care of. We do
+        // this *before* running any other thread, to ensure that timeouts "in the past" fire before
+        // any other thread can take an action. This ensures that for `pthread_cond_timedwait`, "an
+        // error is returned if [...] the absolute time specified by abstime has already been passed
+        // at the time of the call".
+        // <https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_timedwait.html>
+        let potential_sleep_time =
+            self.timeout_callbacks.values().map(|info| info.call_time.get_wait_time(clock)).min();
+        if potential_sleep_time == Some(Duration::new(0, 0)) {
+            return Ok(SchedulingAction::ExecuteTimeoutCallback);
+        }
+        // No callbacks scheduled, pick a regular thread to execute.
+        // The active thread blocked or yielded. So we go search for another enabled thread.
+        // Crucially, we start searching at the current active thread ID, rather than at 0, since we
+        // want to avoid always scheduling threads 0 and 1 without ever making progress in thread 2.
+        //
+        // `skip(N)` means we start iterating at thread N, so we skip 1 more to start just *after*
+        // the active thread. Then after that we look at `take(N)`, i.e., the threads *before* the
+        // active thread.
+        let threads = self
+            .threads
+            .iter_enumerated()
+            .skip(self.active_thread.index() + 1)
+            .chain(self.threads.iter_enumerated().take(self.active_thread.index()));
+        for (id, thread) in threads {
+            debug_assert_ne!(self.active_thread, id);
+            if thread.state == ThreadState::Enabled {
+                self.active_thread = id;
+                break;
+            }
+        }
+        self.yield_active_thread = false;
+        if self.threads[self.active_thread].state == ThreadState::Enabled {
+            return Ok(SchedulingAction::ExecuteStep);
+        }
+        // We have not found a thread to execute.
+        if self.threads.iter().all(|thread| thread.state == ThreadState::Terminated) {
+            unreachable!("all threads terminated without the main thread terminating?!");
+        } else if let Some(sleep_time) = potential_sleep_time {
+            // All threads are currently blocked, but we have unexecuted
+            // timeout_callbacks, which may unblock some of the threads. Hence,
+            // sleep until the first callback.
+
+            clock.sleep(sleep_time);
+            Ok(SchedulingAction::ExecuteTimeoutCallback)
+        } else {
+            throw_machine_stop!(TerminationInfo::Deadlock);
+        }
+    }
+}
+
+// Public interface to thread management.
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Get a thread-specific allocation id for the given thread-local static.
+    /// If needed, allocate a new one.
+    fn get_or_create_thread_local_alloc(
+        &mut self,
+        def_id: DefId,
+    ) -> InterpResult<'tcx, Pointer<Provenance>> {
+        let this = self.eval_context_mut();
+        let tcx = this.tcx;
+        if let Some(old_alloc) = this.machine.threads.get_thread_local_alloc_id(def_id) {
+            // We already have a thread-specific allocation id for this
+            // thread-local static.
+            Ok(old_alloc)
+        } else {
+            // We need to allocate a thread-specific allocation id for this
+            // thread-local static.
+            // First, we compute the initial value for this static.
+            if tcx.is_foreign_item(def_id) {
+                throw_unsup_format!("foreign thread-local statics are not supported");
+            }
+            let allocation = tcx.eval_static_initializer(def_id)?;
+            let mut allocation = allocation.inner().clone();
+            // This allocation will be deallocated when the thread dies, so it is not in read-only memory.
+            allocation.mutability = Mutability::Mut;
+            // Create a fresh allocation with this content.
+            let new_alloc = this.allocate_raw_ptr(allocation, MiriMemoryKind::Tls.into())?;
+            this.machine.threads.set_thread_local_alloc(def_id, new_alloc);
+            Ok(new_alloc)
+        }
+    }
+
+    #[inline]
+    fn create_thread(&mut self) -> ThreadId {
+        let this = self.eval_context_mut();
+        let id = this.machine.threads.create_thread();
+        if let Some(data_race) = &mut this.machine.data_race {
+            data_race.thread_created(&this.machine.threads, id);
+        }
+        id
+    }
+
+    #[inline]
+    fn start_thread(
+        &mut self,
+        thread: Option<MPlaceTy<'tcx, Provenance>>,
+        start_routine: Pointer<Option<Provenance>>,
+        start_abi: Abi,
+        func_arg: ImmTy<'tcx, Provenance>,
+        ret_layout: TyAndLayout<'tcx>,
+    ) -> InterpResult<'tcx, ThreadId> {
+        let this = self.eval_context_mut();
+
+        // Create the new thread
+        let new_thread_id = this.create_thread();
+
+        // Write the current thread-id, switch to the next thread later
+        // to treat this write operation as occuring on the current thread.
+        if let Some(thread_info_place) = thread {
+            this.write_scalar(
+                Scalar::from_uint(new_thread_id.to_u32(), thread_info_place.layout.size),
+                &thread_info_place.into(),
+            )?;
+        }
+
+        // Finally switch to new thread so that we can push the first stackframe.
+        // After this all accesses will be treated as occuring in the new thread.
+        let old_thread_id = this.set_active_thread(new_thread_id);
+
+        // Perform the function pointer load in the new thread frame.
+        let instance = this.get_ptr_fn(start_routine)?.as_instance()?;
+
+        // Note: the returned value is currently ignored (see the FIXME in
+        // pthread_join in shims/unix/thread.rs) because the Rust standard library does not use
+        // it.
+        let ret_place = this.allocate(ret_layout, MiriMemoryKind::Machine.into())?;
+
+        this.call_function(
+            instance,
+            start_abi,
+            &[*func_arg],
+            Some(&ret_place.into()),
+            StackPopCleanup::Root { cleanup: true },
+        )?;
+
+        // Restore the old active thread frame.
+        this.set_active_thread(old_thread_id);
+
+        Ok(new_thread_id)
+    }
+
+    #[inline]
+    fn detach_thread(
+        &mut self,
+        thread_id: ThreadId,
+        allow_terminated_joined: bool,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        this.machine.threads.detach_thread(thread_id, allow_terminated_joined)
+    }
+
+    #[inline]
+    fn join_thread(&mut self, joined_thread_id: ThreadId) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        this.machine.threads.join_thread(joined_thread_id, this.machine.data_race.as_mut())?;
+        Ok(())
+    }
+
+    #[inline]
+    fn join_thread_exclusive(&mut self, joined_thread_id: ThreadId) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        this.machine
+            .threads
+            .join_thread_exclusive(joined_thread_id, this.machine.data_race.as_mut())?;
+        Ok(())
+    }
+
+    #[inline]
+    fn set_active_thread(&mut self, thread_id: ThreadId) -> ThreadId {
+        let this = self.eval_context_mut();
+        this.machine.threads.set_active_thread_id(thread_id)
+    }
+
+    #[inline]
+    fn get_active_thread(&self) -> ThreadId {
+        let this = self.eval_context_ref();
+        this.machine.threads.get_active_thread_id()
+    }
+
+    #[inline]
+    fn active_thread_mut(&mut self) -> &mut Thread<'mir, 'tcx> {
+        let this = self.eval_context_mut();
+        this.machine.threads.active_thread_mut()
+    }
+
+    #[inline]
+    fn active_thread_ref(&self) -> &Thread<'mir, 'tcx> {
+        let this = self.eval_context_ref();
+        this.machine.threads.active_thread_ref()
+    }
+
+    #[inline]
+    fn get_total_thread_count(&self) -> usize {
+        let this = self.eval_context_ref();
+        this.machine.threads.get_total_thread_count()
+    }
+
+    #[inline]
+    fn has_terminated(&self, thread_id: ThreadId) -> bool {
+        let this = self.eval_context_ref();
+        this.machine.threads.has_terminated(thread_id)
+    }
+
+    #[inline]
+    fn have_all_terminated(&self) -> bool {
+        let this = self.eval_context_ref();
+        this.machine.threads.have_all_terminated()
+    }
+
+    #[inline]
+    fn enable_thread(&mut self, thread_id: ThreadId) {
+        let this = self.eval_context_mut();
+        this.machine.threads.enable_thread(thread_id);
+    }
+
+    #[inline]
+    fn active_thread_stack(&self) -> &[Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>] {
+        let this = self.eval_context_ref();
+        this.machine.threads.active_thread_stack()
+    }
+
+    #[inline]
+    fn active_thread_stack_mut(
+        &mut self,
+    ) -> &mut Vec<Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>> {
+        let this = self.eval_context_mut();
+        this.machine.threads.active_thread_stack_mut()
+    }
+
+    #[inline]
+    fn set_thread_name(&mut self, thread: ThreadId, new_thread_name: Vec<u8>) {
+        let this = self.eval_context_mut();
+        this.machine.threads.set_thread_name(thread, new_thread_name);
+    }
+
+    #[inline]
+    fn set_thread_name_wide(&mut self, thread: ThreadId, new_thread_name: &[u16]) {
+        let this = self.eval_context_mut();
+
+        // The Windows `GetThreadDescription` shim to get the thread name isn't implemented, so being lossy is okay.
+        // This is only read by diagnostics, which already use `from_utf8_lossy`.
+        this.machine
+            .threads
+            .set_thread_name(thread, String::from_utf16_lossy(new_thread_name).into_bytes());
+    }
+
+    #[inline]
+    fn get_thread_name<'c>(&'c self, thread: ThreadId) -> &'c [u8]
+    where
+        'mir: 'c,
+    {
+        let this = self.eval_context_ref();
+        this.machine.threads.get_thread_name(thread)
+    }
+
+    #[inline]
+    fn block_thread(&mut self, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        this.machine.threads.block_thread(thread);
+    }
+
+    #[inline]
+    fn unblock_thread(&mut self, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        this.machine.threads.unblock_thread(thread);
+    }
+
+    #[inline]
+    fn yield_active_thread(&mut self) {
+        let this = self.eval_context_mut();
+        this.machine.threads.yield_active_thread();
+    }
+
+    #[inline]
+    fn maybe_preempt_active_thread(&mut self) {
+        use rand::Rng as _;
+
+        let this = self.eval_context_mut();
+        if this.machine.rng.get_mut().gen_bool(this.machine.preemption_rate) {
+            this.yield_active_thread();
+        }
+    }
+
+    #[inline]
+    fn register_timeout_callback(
+        &mut self,
+        thread: ThreadId,
+        call_time: Time,
+        callback: TimeoutCallback<'mir, 'tcx>,
+    ) {
+        let this = self.eval_context_mut();
+        if !this.machine.communicate() && matches!(call_time, Time::RealTime(..)) {
+            panic!("cannot have `RealTime` callback with isolation enabled!")
+        }
+        this.machine.threads.register_timeout_callback(thread, call_time, callback);
+    }
+
+    #[inline]
+    fn unregister_timeout_callback_if_exists(&mut self, thread: ThreadId) {
+        let this = self.eval_context_mut();
+        this.machine.threads.unregister_timeout_callback_if_exists(thread);
+    }
+
+    /// Execute a timeout callback on the callback's thread.
+    #[inline]
+    fn run_timeout_callback(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let (thread, callback) = if let Some((thread, callback)) =
+            this.machine.threads.get_ready_callback(&this.machine.clock)
+        {
+            (thread, callback)
+        } else {
+            // get_ready_callback can return None if the computer's clock
+            // was shifted after calling the scheduler and before the call
+            // to get_ready_callback (see issue
+            // https://github.com/rust-lang/miri/issues/1763). In this case,
+            // just do nothing, which effectively just returns to the
+            // scheduler.
+            return Ok(());
+        };
+        // This back-and-forth with `set_active_thread` is here because of two
+        // design decisions:
+        // 1. Make the caller and not the callback responsible for changing
+        //    thread.
+        // 2. Make the scheduler the only place that can change the active
+        //    thread.
+        let old_thread = this.set_active_thread(thread);
+        callback(this)?;
+        this.set_active_thread(old_thread);
+        Ok(())
+    }
+
+    /// Decide which action to take next and on which thread.
+    #[inline]
+    fn schedule(&mut self) -> InterpResult<'tcx, SchedulingAction> {
+        let this = self.eval_context_mut();
+        this.machine.threads.schedule(&this.machine.clock)
+    }
+
+    /// Handles thread termination of the active thread: wakes up threads joining on this one,
+    /// and deallocated thread-local statics.
+    ///
+    /// This is called from `tls.rs` after handling the TLS dtors.
+    #[inline]
+    fn thread_terminated(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        for ptr in this.machine.threads.thread_terminated(this.machine.data_race.as_mut()) {
+            this.deallocate_ptr(ptr.into(), None, MiriMemoryKind::Tls.into())?;
+        }
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/concurrency/vector_clock.rs b/src/tools/miri/src/concurrency/vector_clock.rs
new file mode 100644
index 000000000000..32449f8eb188
--- /dev/null
+++ b/src/tools/miri/src/concurrency/vector_clock.rs
@@ -0,0 +1,470 @@
+use rustc_index::vec::Idx;
+use smallvec::SmallVec;
+use std::{cmp::Ordering, fmt::Debug, ops::Index};
+
+/// A vector clock index, this is associated with a thread id
+/// but in some cases one vector index may be shared with
+/// multiple thread ids if it safe to do so.
+#[derive(Clone, Copy, Debug, PartialOrd, Ord, PartialEq, Eq, Hash)]
+pub struct VectorIdx(u32);
+
+impl VectorIdx {
+    #[inline(always)]
+    pub fn to_u32(self) -> u32 {
+        self.0
+    }
+
+    pub const MAX_INDEX: VectorIdx = VectorIdx(u32::MAX);
+}
+
+impl Idx for VectorIdx {
+    #[inline]
+    fn new(idx: usize) -> Self {
+        VectorIdx(u32::try_from(idx).unwrap())
+    }
+
+    #[inline]
+    fn index(self) -> usize {
+        usize::try_from(self.0).unwrap()
+    }
+}
+
+impl From<u32> for VectorIdx {
+    #[inline]
+    fn from(id: u32) -> Self {
+        Self(id)
+    }
+}
+
+/// The size of the vector-clock to store inline
+/// clock vectors larger than this will be stored on the heap
+const SMALL_VECTOR: usize = 4;
+
+/// The type of the time-stamps recorded in the data-race detector
+/// set to a type of unsigned integer
+pub type VTimestamp = u32;
+
+/// A vector clock for detecting data-races, this is conceptually
+/// a map from a vector index (and thus a thread id) to a timestamp.
+/// The compare operations require that the invariant that the last
+/// element in the internal timestamp slice must not be a 0, hence
+/// all zero vector clocks are always represented by the empty slice;
+/// and allows for the implementation of compare operations to short
+/// circuit the calculation and return the correct result faster,
+/// also this means that there is only one unique valid length
+/// for each set of vector clock values and hence the PartialEq
+/// and Eq derivations are correct.
+#[derive(PartialEq, Eq, Default, Debug)]
+pub struct VClock(SmallVec<[VTimestamp; SMALL_VECTOR]>);
+
+impl VClock {
+    /// Create a new vector-clock containing all zeros except
+    /// for a value at the given index
+    pub fn new_with_index(index: VectorIdx, timestamp: VTimestamp) -> VClock {
+        let len = index.index() + 1;
+        let mut vec = smallvec::smallvec![0; len];
+        vec[index.index()] = timestamp;
+        VClock(vec)
+    }
+
+    /// Load the internal timestamp slice in the vector clock
+    #[inline]
+    pub fn as_slice(&self) -> &[VTimestamp] {
+        self.0.as_slice()
+    }
+
+    /// Get a mutable slice to the internal vector with minimum `min_len`
+    /// elements, to preserve invariants this vector must modify
+    /// the `min_len`-1 nth element to a non-zero value
+    #[inline]
+    fn get_mut_with_min_len(&mut self, min_len: usize) -> &mut [VTimestamp] {
+        if self.0.len() < min_len {
+            self.0.resize(min_len, 0);
+        }
+        assert!(self.0.len() >= min_len);
+        self.0.as_mut_slice()
+    }
+
+    /// Increment the vector clock at a known index
+    /// this will panic if the vector index overflows
+    #[inline]
+    pub fn increment_index(&mut self, idx: VectorIdx) {
+        let idx = idx.index();
+        let mut_slice = self.get_mut_with_min_len(idx + 1);
+        let idx_ref = &mut mut_slice[idx];
+        *idx_ref = idx_ref.checked_add(1).expect("Vector clock overflow")
+    }
+
+    // Join the two vector-clocks together, this
+    // sets each vector-element to the maximum value
+    // of that element in either of the two source elements.
+    pub fn join(&mut self, other: &Self) {
+        let rhs_slice = other.as_slice();
+        let lhs_slice = self.get_mut_with_min_len(rhs_slice.len());
+        for (l, &r) in lhs_slice.iter_mut().zip(rhs_slice.iter()) {
+            *l = r.max(*l);
+        }
+    }
+
+    /// Set the element at the current index of the vector
+    pub fn set_at_index(&mut self, other: &Self, idx: VectorIdx) {
+        let mut_slice = self.get_mut_with_min_len(idx.index() + 1);
+        mut_slice[idx.index()] = other[idx];
+    }
+
+    /// Set the vector to the all-zero vector
+    #[inline]
+    pub fn set_zero_vector(&mut self) {
+        self.0.clear();
+    }
+
+    /// Return if this vector is the all-zero vector
+    pub fn is_zero_vector(&self) -> bool {
+        self.0.is_empty()
+    }
+}
+
+impl Clone for VClock {
+    fn clone(&self) -> Self {
+        VClock(self.0.clone())
+    }
+
+    // Optimized clone-from, can be removed
+    // and replaced with a derive once a similar
+    // optimization is inserted into SmallVec's
+    // clone implementation.
+    fn clone_from(&mut self, source: &Self) {
+        let source_slice = source.as_slice();
+        self.0.clear();
+        self.0.extend_from_slice(source_slice);
+    }
+}
+
+impl PartialOrd for VClock {
+    fn partial_cmp(&self, other: &VClock) -> Option<Ordering> {
+        // Load the values as slices
+        let lhs_slice = self.as_slice();
+        let rhs_slice = other.as_slice();
+
+        // Iterate through the combined vector slice continuously updating
+        // the value of `order` to the current comparison of the vector from
+        // index 0 to the currently checked index.
+        // An Equal ordering can be converted into Less or Greater ordering
+        // on finding an element that is less than or greater than the other
+        // but if one Greater and one Less element-wise comparison is found
+        // then no ordering is possible and so directly return an ordering
+        // of None.
+        let mut iter = lhs_slice.iter().zip(rhs_slice.iter());
+        let mut order = match iter.next() {
+            Some((lhs, rhs)) => lhs.cmp(rhs),
+            None => Ordering::Equal,
+        };
+        for (l, r) in iter {
+            match order {
+                Ordering::Equal => order = l.cmp(r),
+                Ordering::Less =>
+                    if l > r {
+                        return None;
+                    },
+                Ordering::Greater =>
+                    if l < r {
+                        return None;
+                    },
+            }
+        }
+
+        // Now test if either left or right have trailing elements,
+        // by the invariant the trailing elements have at least 1
+        // non zero value, so no additional calculation is required
+        // to determine the result of the PartialOrder.
+        let l_len = lhs_slice.len();
+        let r_len = rhs_slice.len();
+        match l_len.cmp(&r_len) {
+            // Equal means no additional elements: return current order
+            Ordering::Equal => Some(order),
+            // Right has at least 1 element > than the implicit 0,
+            // so the only valid values are Ordering::Less or None.
+            Ordering::Less =>
+                match order {
+                    Ordering::Less | Ordering::Equal => Some(Ordering::Less),
+                    Ordering::Greater => None,
+                },
+            // Left has at least 1 element > than the implicit 0,
+            // so the only valid values are Ordering::Greater or None.
+            Ordering::Greater =>
+                match order {
+                    Ordering::Greater | Ordering::Equal => Some(Ordering::Greater),
+                    Ordering::Less => None,
+                },
+        }
+    }
+
+    fn lt(&self, other: &VClock) -> bool {
+        // Load the values as slices
+        let lhs_slice = self.as_slice();
+        let rhs_slice = other.as_slice();
+
+        // If l_len > r_len then at least one element
+        // in l_len is > than r_len, therefore the result
+        // is either Some(Greater) or None, so return false
+        // early.
+        let l_len = lhs_slice.len();
+        let r_len = rhs_slice.len();
+        if l_len <= r_len {
+            // If any elements on the left are greater than the right
+            // then the result is None or Some(Greater), both of which
+            // return false, the earlier test asserts that no elements in the
+            // extended tail violate this assumption. Otherwise l <= r, finally
+            // the case where the values are potentially equal needs to be considered
+            // and false returned as well
+            let mut equal = l_len == r_len;
+            for (&l, &r) in lhs_slice.iter().zip(rhs_slice.iter()) {
+                if l > r {
+                    return false;
+                } else if l < r {
+                    equal = false;
+                }
+            }
+            !equal
+        } else {
+            false
+        }
+    }
+
+    fn le(&self, other: &VClock) -> bool {
+        // Load the values as slices
+        let lhs_slice = self.as_slice();
+        let rhs_slice = other.as_slice();
+
+        // If l_len > r_len then at least one element
+        // in l_len is > than r_len, therefore the result
+        // is either Some(Greater) or None, so return false
+        // early.
+        let l_len = lhs_slice.len();
+        let r_len = rhs_slice.len();
+        if l_len <= r_len {
+            // If any elements on the left are greater than the right
+            // then the result is None or Some(Greater), both of which
+            // return false, the earlier test asserts that no elements in the
+            // extended tail violate this assumption. Otherwise l <= r
+            !lhs_slice.iter().zip(rhs_slice.iter()).any(|(&l, &r)| l > r)
+        } else {
+            false
+        }
+    }
+
+    fn gt(&self, other: &VClock) -> bool {
+        // Load the values as slices
+        let lhs_slice = self.as_slice();
+        let rhs_slice = other.as_slice();
+
+        // If r_len > l_len then at least one element
+        // in r_len is > than l_len, therefore the result
+        // is either Some(Less) or None, so return false
+        // early.
+        let l_len = lhs_slice.len();
+        let r_len = rhs_slice.len();
+        if l_len >= r_len {
+            // If any elements on the left are less than the right
+            // then the result is None or Some(Less), both of which
+            // return false, the earlier test asserts that no elements in the
+            // extended tail violate this assumption. Otherwise l >=, finally
+            // the case where the values are potentially equal needs to be considered
+            // and false returned as well
+            let mut equal = l_len == r_len;
+            for (&l, &r) in lhs_slice.iter().zip(rhs_slice.iter()) {
+                if l < r {
+                    return false;
+                } else if l > r {
+                    equal = false;
+                }
+            }
+            !equal
+        } else {
+            false
+        }
+    }
+
+    fn ge(&self, other: &VClock) -> bool {
+        // Load the values as slices
+        let lhs_slice = self.as_slice();
+        let rhs_slice = other.as_slice();
+
+        // If r_len > l_len then at least one element
+        // in r_len is > than l_len, therefore the result
+        // is either Some(Less) or None, so return false
+        // early.
+        let l_len = lhs_slice.len();
+        let r_len = rhs_slice.len();
+        if l_len >= r_len {
+            // If any elements on the left are less than the right
+            // then the result is None or Some(Less), both of which
+            // return false, the earlier test asserts that no elements in the
+            // extended tail violate this assumption. Otherwise l >= r
+            !lhs_slice.iter().zip(rhs_slice.iter()).any(|(&l, &r)| l < r)
+        } else {
+            false
+        }
+    }
+}
+
+impl Index<VectorIdx> for VClock {
+    type Output = VTimestamp;
+
+    #[inline]
+    fn index(&self, index: VectorIdx) -> &VTimestamp {
+        self.as_slice().get(index.to_u32() as usize).unwrap_or(&0)
+    }
+}
+
+/// Test vector clock ordering operations
+///  data-race detection is tested in the external
+///  test suite
+#[cfg(test)]
+mod tests {
+
+    use super::{VClock, VTimestamp, VectorIdx};
+    use std::cmp::Ordering;
+
+    #[test]
+    fn test_equal() {
+        let mut c1 = VClock::default();
+        let mut c2 = VClock::default();
+        assert_eq!(c1, c2);
+        c1.increment_index(VectorIdx(5));
+        assert_ne!(c1, c2);
+        c2.increment_index(VectorIdx(53));
+        assert_ne!(c1, c2);
+        c1.increment_index(VectorIdx(53));
+        assert_ne!(c1, c2);
+        c2.increment_index(VectorIdx(5));
+        assert_eq!(c1, c2);
+    }
+
+    #[test]
+    fn test_partial_order() {
+        // Small test
+        assert_order(&[1], &[1], Some(Ordering::Equal));
+        assert_order(&[1], &[2], Some(Ordering::Less));
+        assert_order(&[2], &[1], Some(Ordering::Greater));
+        assert_order(&[1], &[1, 2], Some(Ordering::Less));
+        assert_order(&[2], &[1, 2], None);
+
+        // Misc tests
+        assert_order(&[400], &[0, 1], None);
+
+        // Large test
+        assert_order(
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0],
+            Some(Ordering::Equal),
+        );
+        assert_order(
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 0],
+            Some(Ordering::Less),
+        );
+        assert_order(
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11],
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0],
+            Some(Ordering::Greater),
+        );
+        assert_order(
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11],
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 0],
+            None,
+        );
+        assert_order(
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9],
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0],
+            Some(Ordering::Less),
+        );
+        assert_order(
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9],
+            &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 0],
+            Some(Ordering::Less),
+        );
+    }
+
+    fn from_slice(mut slice: &[VTimestamp]) -> VClock {
+        while let Some(0) = slice.last() {
+            slice = &slice[..slice.len() - 1]
+        }
+        VClock(smallvec::SmallVec::from_slice(slice))
+    }
+
+    fn assert_order(l: &[VTimestamp], r: &[VTimestamp], o: Option<Ordering>) {
+        let l = from_slice(l);
+        let r = from_slice(r);
+
+        //Test partial_cmp
+        let compare = l.partial_cmp(&r);
+        assert_eq!(compare, o, "Invalid comparison\n l: {:?}\n r: {:?}", l, r);
+        let alt_compare = r.partial_cmp(&l);
+        assert_eq!(
+            alt_compare,
+            o.map(Ordering::reverse),
+            "Invalid alt comparison\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+
+        //Test operators with faster implementations
+        assert_eq!(
+            matches!(compare, Some(Ordering::Less)),
+            l < r,
+            "Invalid (<):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(compare, Some(Ordering::Less) | Some(Ordering::Equal)),
+            l <= r,
+            "Invalid (<=):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(compare, Some(Ordering::Greater)),
+            l > r,
+            "Invalid (>):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(compare, Some(Ordering::Greater) | Some(Ordering::Equal)),
+            l >= r,
+            "Invalid (>=):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(alt_compare, Some(Ordering::Less)),
+            r < l,
+            "Invalid alt (<):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(alt_compare, Some(Ordering::Less) | Some(Ordering::Equal)),
+            r <= l,
+            "Invalid alt (<=):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(alt_compare, Some(Ordering::Greater)),
+            r > l,
+            "Invalid alt (>):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+        assert_eq!(
+            matches!(alt_compare, Some(Ordering::Greater) | Some(Ordering::Equal)),
+            r >= l,
+            "Invalid alt (>=):\n l: {:?}\n r: {:?}",
+            l,
+            r
+        );
+    }
+}
diff --git a/src/tools/miri/src/concurrency/weak_memory.rs b/src/tools/miri/src/concurrency/weak_memory.rs
new file mode 100644
index 000000000000..bac403e9ec7b
--- /dev/null
+++ b/src/tools/miri/src/concurrency/weak_memory.rs
@@ -0,0 +1,630 @@
+//! Implementation of C++11-consistent weak memory emulation using store buffers
+//! based on Dynamic Race Detection for C++ ("the paper"):
+//! <https://www.doc.ic.ac.uk/~afd/homepages/papers/pdfs/2017/POPL.pdf>
+//!
+//! This implementation will never generate weak memory behaviours forbidden by the C++11 model,
+//! but it is incapable of producing all possible weak behaviours allowed by the model. There are
+//! certain weak behaviours observable on real hardware but not while using this.
+//!
+//! Note that this implementation does not fully take into account of C++20's memory model revision to SC accesses
+//! and fences introduced by P0668 (<https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0668r5.html>).
+//! This implementation is not fully correct under the revised C++20 model and may generate behaviours C++20
+//! disallows (<https://github.com/rust-lang/miri/issues/2301>).
+//!
+//! A modification is made to the paper's model to partially address C++20 changes.
+//! Specifically, if an SC load reads from an atomic store of any ordering, then a later SC load cannot read from
+//! an earlier store in the location's modification order. This is to prevent creating a backwards S edge from the second
+//! load to the first, as a result of C++20's coherence-ordered before rules.
+//!
+//! Rust follows the C++20 memory model (except for the Consume ordering and some operations not performable through C++'s
+//! std::atomic<T> API). It is therefore possible for this implementation to generate behaviours never observable when the
+//! same program is compiled and run natively. Unfortunately, no literature exists at the time of writing which proposes
+//! an implementable and C++20-compatible relaxed memory model that supports all atomic operation existing in Rust. The closest one is
+//! A Promising Semantics for Relaxed-Memory Concurrency by Jeehoon Kang et al. (<https://www.cs.tau.ac.il/~orilahav/papers/popl17.pdf>)
+//! However, this model lacks SC accesses and is therefore unusable by Miri (SC accesses are everywhere in library code).
+//!
+//! If you find anything that proposes a relaxed memory model that is C++20-consistent, supports all orderings Rust's atomic accesses
+//! and fences accept, and is implementable (with operational semanitcs), please open a GitHub issue!
+//!
+//! One characteristic of this implementation, in contrast to some other notable operational models such as ones proposed in
+//! Taming Release-Acquire Consistency by Ori Lahav et al. (<https://plv.mpi-sws.org/sra/paper.pdf>) or Promising Semantics noted above,
+//! is that this implementation does not require each thread to hold an isolated view of the entire memory. Here, store buffers are per-location
+//! and shared across all threads. This is more memory efficient but does require store elements (representing writes to a location) to record
+//! information about reads, whereas in the other two models it is the other way round: reads points to the write it got its value from.
+//! Additionally, writes in our implementation do not have globally unique timestamps attached. In the other two models this timestamp is
+//! used to make sure a value in a thread's view is not overwritten by a write that occured earlier than the one in the existing view.
+//! In our implementation, this is detected using read information attached to store elements, as there is no data strucutre representing reads.
+//!
+//! The C++ memory model is built around the notion of an 'atomic object', so it would be natural
+//! to attach store buffers to atomic objects. However, Rust follows LLVM in that it only has
+//! 'atomic accesses'. Therefore Miri cannot know when and where atomic 'objects' are being
+//! created or destroyed, to manage its store buffers. Instead, we hence lazily create an
+//! atomic object on the first atomic access to a given region, and we destroy that object
+//! on the next non-atomic or imperfectly overlapping atomic access to that region.
+//! These lazy (de)allocations happen in memory_accessed() on non-atomic accesses, and
+//! get_or_create_store_buffer() on atomic accesses. This mostly works well, but it does
+//! lead to some issues (<https://github.com/rust-lang/miri/issues/2164>).
+//!
+//! One consequence of this difference is that safe/sound Rust allows for more operations on atomic locations
+//! than the C++20 atomic API was intended to allow, such as non-atomically accessing
+//! a previously atomically accessed location, or accessing previously atomically accessed locations with a differently sized operation
+//! (such as accessing the top 16 bits of an AtomicU32). These senarios are generally undiscussed in formalisations of C++ memory model.
+//! In Rust, these operations can only be done through a `&mut AtomicFoo` reference or one derived from it, therefore these operations
+//! can only happen after all previous accesses on the same locations. This implementation is adapted to allow these operations.
+//! A mixed atomicity read that races with writes, or a write that races with reads or writes will still cause UBs to be thrown.
+//! Mixed size atomic accesses must not race with any other atomic access, whether read or write, or a UB will be thrown.
+//! You can refer to test cases in weak_memory/extra_cpp.rs and weak_memory/extra_cpp_unsafe.rs for examples of these operations.
+
+// Our and the author's own implementation (tsan11) of the paper have some deviations from the provided operational semantics in §5.3:
+// 1. In the operational semantics, store elements keep a copy of the atomic object's vector clock (AtomicCellClocks::sync_vector in miri),
+// but this is not used anywhere so it's omitted here.
+//
+// 2. In the operational semantics, each store element keeps the timestamp of a thread when it loads from the store.
+// If the same thread loads from the same store element multiple times, then the timestamps at all loads are saved in a list of load elements.
+// This is not necessary as later loads by the same thread will always have greater timetstamp values, so we only need to record the timestamp of the first
+// load by each thread. This optimisation is done in tsan11
+// (https://github.com/ChrisLidbury/tsan11/blob/ecbd6b81e9b9454e01cba78eb9d88684168132c7/lib/tsan/rtl/tsan_relaxed.h#L35-L37)
+// and here.
+//
+// 3. §4.5 of the paper wants an SC store to mark all existing stores in the buffer that happens before it
+// as SC. This is not done in the operational semantics but implemented correctly in tsan11
+// (https://github.com/ChrisLidbury/tsan11/blob/ecbd6b81e9b9454e01cba78eb9d88684168132c7/lib/tsan/rtl/tsan_relaxed.cc#L160-L167)
+// and here.
+//
+// 4. W_SC ; R_SC case requires the SC load to ignore all but last store maked SC (stores not marked SC are not
+// affected). But this rule is applied to all loads in ReadsFromSet from the paper (last two lines of code), not just SC load.
+// This is implemented correctly in tsan11
+// (https://github.com/ChrisLidbury/tsan11/blob/ecbd6b81e9b9454e01cba78eb9d88684168132c7/lib/tsan/rtl/tsan_relaxed.cc#L295)
+// and here.
+
+use std::{
+    cell::{Ref, RefCell},
+    collections::VecDeque,
+};
+
+use rustc_const_eval::interpret::{alloc_range, AllocRange, InterpResult, MPlaceTy, Scalar};
+use rustc_data_structures::fx::FxHashMap;
+
+use crate::*;
+
+use super::{
+    data_race::{GlobalState as DataRaceState, ThreadClockSet},
+    range_object_map::{AccessType, RangeObjectMap},
+    vector_clock::{VClock, VTimestamp, VectorIdx},
+};
+
+pub type AllocExtra = StoreBufferAlloc;
+
+// Each store buffer must be bounded otherwise it will grow indefinitely.
+// However, bounding the store buffer means restricting the amount of weak
+// behaviours observable. The author picked 128 as a good tradeoff
+// so we follow them here.
+const STORE_BUFFER_LIMIT: usize = 128;
+
+#[derive(Debug, Clone)]
+pub struct StoreBufferAlloc {
+    /// Store buffer of each atomic object in this allocation
+    // Behind a RefCell because we need to allocate/remove on read access
+    store_buffers: RefCell<RangeObjectMap<StoreBuffer>>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(super) struct StoreBuffer {
+    // Stores to this location in modification order
+    buffer: VecDeque<StoreElement>,
+}
+
+/// Whether a load returned the latest value or not.
+#[derive(PartialEq, Eq)]
+enum LoadRecency {
+    Latest,
+    Outdated,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct StoreElement {
+    /// The identifier of the vector index, corresponding to a thread
+    /// that performed the store.
+    store_index: VectorIdx,
+
+    /// Whether this store is SC.
+    is_seqcst: bool,
+
+    /// The timestamp of the storing thread when it performed the store
+    timestamp: VTimestamp,
+    /// The value of this store
+    // FIXME: this means the store must be fully initialized;
+    // we will have to change this if we want to support atomics on
+    // (partially) uninitialized data.
+    val: Scalar<Provenance>,
+
+    /// Metadata about loads from this store element,
+    /// behind a RefCell to keep load op take &self
+    load_info: RefCell<LoadInfo>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+struct LoadInfo {
+    /// Timestamp of first loads from this store element by each thread
+    timestamps: FxHashMap<VectorIdx, VTimestamp>,
+    /// Whether this store element has been read by an SC load
+    sc_loaded: bool,
+}
+
+impl StoreBufferAlloc {
+    pub fn new_allocation() -> Self {
+        Self { store_buffers: RefCell::new(RangeObjectMap::new()) }
+    }
+
+    /// Checks if the range imperfectly overlaps with existing buffers
+    /// Used to determine if mixed-size atomic accesses
+    fn is_overlapping(&self, range: AllocRange) -> bool {
+        let buffers = self.store_buffers.borrow();
+        let access_type = buffers.access_type(range);
+        matches!(access_type, AccessType::ImperfectlyOverlapping(_))
+    }
+
+    /// When a non-atomic access happens on a location that has been atomically accessed
+    /// before without data race, we can determine that the non-atomic access fully happens
+    /// after all the prior atomic accesses so the location no longer needs to exhibit
+    /// any weak memory behaviours until further atomic accesses.
+    pub fn memory_accessed(&self, range: AllocRange, global: &DataRaceState) {
+        if !global.ongoing_action_data_race_free() {
+            let mut buffers = self.store_buffers.borrow_mut();
+            let access_type = buffers.access_type(range);
+            match access_type {
+                AccessType::PerfectlyOverlapping(pos) => {
+                    buffers.remove_from_pos(pos);
+                }
+                AccessType::ImperfectlyOverlapping(pos_range) => {
+                    buffers.remove_pos_range(pos_range);
+                }
+                AccessType::Empty(_) => {
+                    // The range had no weak behaivours attached, do nothing
+                }
+            }
+        }
+    }
+
+    /// Gets a store buffer associated with an atomic object in this allocation,
+    /// or creates one with the specified initial value if no atomic object exists yet.
+    fn get_or_create_store_buffer<'tcx>(
+        &self,
+        range: AllocRange,
+        init: Scalar<Provenance>,
+    ) -> InterpResult<'tcx, Ref<'_, StoreBuffer>> {
+        let access_type = self.store_buffers.borrow().access_type(range);
+        let pos = match access_type {
+            AccessType::PerfectlyOverlapping(pos) => pos,
+            AccessType::Empty(pos) => {
+                let mut buffers = self.store_buffers.borrow_mut();
+                buffers.insert_at_pos(pos, range, StoreBuffer::new(init));
+                pos
+            }
+            AccessType::ImperfectlyOverlapping(pos_range) => {
+                // Once we reach here we would've already checked that this access is not racy
+                let mut buffers = self.store_buffers.borrow_mut();
+                buffers.remove_pos_range(pos_range.clone());
+                buffers.insert_at_pos(pos_range.start, range, StoreBuffer::new(init));
+                pos_range.start
+            }
+        };
+        Ok(Ref::map(self.store_buffers.borrow(), |buffer| &buffer[pos]))
+    }
+
+    /// Gets a mutable store buffer associated with an atomic object in this allocation
+    fn get_or_create_store_buffer_mut<'tcx>(
+        &mut self,
+        range: AllocRange,
+        init: Scalar<Provenance>,
+    ) -> InterpResult<'tcx, &mut StoreBuffer> {
+        let buffers = self.store_buffers.get_mut();
+        let access_type = buffers.access_type(range);
+        let pos = match access_type {
+            AccessType::PerfectlyOverlapping(pos) => pos,
+            AccessType::Empty(pos) => {
+                buffers.insert_at_pos(pos, range, StoreBuffer::new(init));
+                pos
+            }
+            AccessType::ImperfectlyOverlapping(pos_range) => {
+                buffers.remove_pos_range(pos_range.clone());
+                buffers.insert_at_pos(pos_range.start, range, StoreBuffer::new(init));
+                pos_range.start
+            }
+        };
+        Ok(&mut buffers[pos])
+    }
+}
+
+impl<'mir, 'tcx: 'mir> StoreBuffer {
+    fn new(init: Scalar<Provenance>) -> Self {
+        let mut buffer = VecDeque::new();
+        buffer.reserve(STORE_BUFFER_LIMIT);
+        let mut ret = Self { buffer };
+        let store_elem = StoreElement {
+            // The thread index and timestamp of the initialisation write
+            // are never meaningfully used, so it's fine to leave them as 0
+            store_index: VectorIdx::from(0),
+            timestamp: 0,
+            val: init,
+            is_seqcst: false,
+            load_info: RefCell::new(LoadInfo::default()),
+        };
+        ret.buffer.push_back(store_elem);
+        ret
+    }
+
+    /// Reads from the last store in modification order
+    fn read_from_last_store(
+        &self,
+        global: &DataRaceState,
+        thread_mgr: &ThreadManager<'_, '_>,
+        is_seqcst: bool,
+    ) {
+        let store_elem = self.buffer.back();
+        if let Some(store_elem) = store_elem {
+            let (index, clocks) = global.current_thread_state(thread_mgr);
+            store_elem.load_impl(index, &clocks, is_seqcst);
+        }
+    }
+
+    fn buffered_read(
+        &self,
+        global: &DataRaceState,
+        thread_mgr: &ThreadManager<'_, '_>,
+        is_seqcst: bool,
+        rng: &mut (impl rand::Rng + ?Sized),
+        validate: impl FnOnce() -> InterpResult<'tcx>,
+    ) -> InterpResult<'tcx, (Scalar<Provenance>, LoadRecency)> {
+        // Having a live borrow to store_buffer while calling validate_atomic_load is fine
+        // because the race detector doesn't touch store_buffer
+
+        let (store_elem, recency) = {
+            // The `clocks` we got here must be dropped before calling validate_atomic_load
+            // as the race detector will update it
+            let (.., clocks) = global.current_thread_state(thread_mgr);
+            // Load from a valid entry in the store buffer
+            self.fetch_store(is_seqcst, &clocks, &mut *rng)
+        };
+
+        // Unlike in buffered_atomic_write, thread clock updates have to be done
+        // after we've picked a store element from the store buffer, as presented
+        // in ATOMIC LOAD rule of the paper. This is because fetch_store
+        // requires access to ThreadClockSet.clock, which is updated by the race detector
+        validate()?;
+
+        let (index, clocks) = global.current_thread_state(thread_mgr);
+        let loaded = store_elem.load_impl(index, &clocks, is_seqcst);
+        Ok((loaded, recency))
+    }
+
+    fn buffered_write(
+        &mut self,
+        val: Scalar<Provenance>,
+        global: &DataRaceState,
+        thread_mgr: &ThreadManager<'_, '_>,
+        is_seqcst: bool,
+    ) -> InterpResult<'tcx> {
+        let (index, clocks) = global.current_thread_state(thread_mgr);
+
+        self.store_impl(val, index, &clocks.clock, is_seqcst);
+        Ok(())
+    }
+
+    #[allow(clippy::if_same_then_else, clippy::needless_bool)]
+    /// Selects a valid store element in the buffer.
+    fn fetch_store<R: rand::Rng + ?Sized>(
+        &self,
+        is_seqcst: bool,
+        clocks: &ThreadClockSet,
+        rng: &mut R,
+    ) -> (&StoreElement, LoadRecency) {
+        use rand::seq::IteratorRandom;
+        let mut found_sc = false;
+        // FIXME: we want an inclusive take_while (stops after a false predicate, but
+        // includes the element that gave the false), but such function doesn't yet
+        // exist in the standard libary https://github.com/rust-lang/rust/issues/62208
+        // so we have to hack around it with keep_searching
+        let mut keep_searching = true;
+        let candidates = self
+            .buffer
+            .iter()
+            .rev()
+            .take_while(move |&store_elem| {
+                if !keep_searching {
+                    return false;
+                }
+
+                keep_searching = if store_elem.timestamp <= clocks.clock[store_elem.store_index] {
+                    // CoWR: if a store happens-before the current load,
+                    // then we can't read-from anything earlier in modification order.
+                    // C++20 §6.9.2.2 [intro.races] paragraph 18
+                    false
+                } else if store_elem.load_info.borrow().timestamps.iter().any(
+                    |(&load_index, &load_timestamp)| load_timestamp <= clocks.clock[load_index],
+                ) {
+                    // CoRR: if there was a load from this store which happened-before the current load,
+                    // then we cannot read-from anything earlier in modification order.
+                    // C++20 §6.9.2.2 [intro.races] paragraph 16
+                    false
+                } else if store_elem.timestamp <= clocks.fence_seqcst[store_elem.store_index] {
+                    // The current load, which may be sequenced-after an SC fence, cannot read-before
+                    // the last store sequenced-before an SC fence in another thread.
+                    // C++17 §32.4 [atomics.order] paragraph 6
+                    false
+                } else if store_elem.timestamp <= clocks.write_seqcst[store_elem.store_index]
+                    && store_elem.is_seqcst
+                {
+                    // The current non-SC load, which may be sequenced-after an SC fence,
+                    // cannot read-before the last SC store executed before the fence.
+                    // C++17 §32.4 [atomics.order] paragraph 4
+                    false
+                } else if is_seqcst
+                    && store_elem.timestamp <= clocks.read_seqcst[store_elem.store_index]
+                {
+                    // The current SC load cannot read-before the last store sequenced-before
+                    // the last SC fence.
+                    // C++17 §32.4 [atomics.order] paragraph 5
+                    false
+                } else if is_seqcst && store_elem.load_info.borrow().sc_loaded {
+                    // The current SC load cannot read-before a store that an earlier SC load has observed.
+                    // See https://github.com/rust-lang/miri/issues/2301#issuecomment-1222720427
+                    // Consequences of C++20 §31.4 [atomics.order] paragraph 3.1, 3.3 (coherence-ordered before)
+                    // and 4.1 (coherence-ordered before between SC makes global total order S)
+                    false
+                } else {
+                    true
+                };
+
+                true
+            })
+            .filter(|&store_elem| {
+                if is_seqcst && store_elem.is_seqcst {
+                    // An SC load needs to ignore all but last store maked SC (stores not marked SC are not
+                    // affected)
+                    let include = !found_sc;
+                    found_sc = true;
+                    include
+                } else {
+                    true
+                }
+            });
+
+        let chosen = candidates.choose(rng).expect("store buffer cannot be empty");
+        if std::ptr::eq(chosen, self.buffer.back().expect("store buffer cannot be empty")) {
+            (chosen, LoadRecency::Latest)
+        } else {
+            (chosen, LoadRecency::Outdated)
+        }
+    }
+
+    /// ATOMIC STORE IMPL in the paper (except we don't need the location's vector clock)
+    fn store_impl(
+        &mut self,
+        val: Scalar<Provenance>,
+        index: VectorIdx,
+        thread_clock: &VClock,
+        is_seqcst: bool,
+    ) {
+        let store_elem = StoreElement {
+            store_index: index,
+            timestamp: thread_clock[index],
+            // In the language provided in the paper, an atomic store takes the value from a
+            // non-atomic memory location.
+            // But we already have the immediate value here so we don't need to do the memory
+            // access
+            val,
+            is_seqcst,
+            load_info: RefCell::new(LoadInfo::default()),
+        };
+        self.buffer.push_back(store_elem);
+        if self.buffer.len() > STORE_BUFFER_LIMIT {
+            self.buffer.pop_front();
+        }
+        if is_seqcst {
+            // Every store that happens before this needs to be marked as SC
+            // so that in a later SC load, only the last SC store (i.e. this one) or stores that
+            // aren't ordered by hb with the last SC is picked.
+            self.buffer.iter_mut().rev().for_each(|elem| {
+                if elem.timestamp <= thread_clock[elem.store_index] {
+                    elem.is_seqcst = true;
+                }
+            })
+        }
+    }
+}
+
+impl StoreElement {
+    /// ATOMIC LOAD IMPL in the paper
+    /// Unlike the operational semantics in the paper, we don't need to keep track
+    /// of the thread timestamp for every single load. Keeping track of the first (smallest)
+    /// timestamp of each thread that has loaded from a store is sufficient: if the earliest
+    /// load of another thread happens before the current one, then we must stop searching the store
+    /// buffer regardless of subsequent loads by the same thread; if the earliest load of another
+    /// thread doesn't happen before the current one, then no subsequent load by the other thread
+    /// can happen before the current one.
+    fn load_impl(
+        &self,
+        index: VectorIdx,
+        clocks: &ThreadClockSet,
+        is_seqcst: bool,
+    ) -> Scalar<Provenance> {
+        let mut load_info = self.load_info.borrow_mut();
+        load_info.sc_loaded |= is_seqcst;
+        let _ = load_info.timestamps.try_insert(index, clocks.clock[index]);
+        self.val
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
+    crate::MiriInterpCxExt<'mir, 'tcx>
+{
+    // If weak memory emulation is enabled, check if this atomic op imperfectly overlaps with a previous
+    // atomic read or write. If it does, then we require it to be ordered (non-racy) with all previous atomic
+    // accesses on all the bytes in range
+    fn validate_overlapping_atomic(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr)?;
+        if let crate::AllocExtra {
+            weak_memory: Some(alloc_buffers),
+            data_race: Some(alloc_clocks),
+            ..
+        } = this.get_alloc_extra(alloc_id)?
+        {
+            let range = alloc_range(base_offset, place.layout.size);
+            if alloc_buffers.is_overlapping(range)
+                && !alloc_clocks.race_free_with_atomic(
+                    range,
+                    this.machine.data_race.as_ref().unwrap(),
+                    &this.machine.threads,
+                )
+            {
+                throw_unsup_format!(
+                    "racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation"
+                );
+            }
+        }
+        Ok(())
+    }
+
+    fn buffered_atomic_rmw(
+        &mut self,
+        new_val: Scalar<Provenance>,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicRwOrd,
+        init: Scalar<Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr)?;
+        if let (
+            crate::AllocExtra { weak_memory: Some(alloc_buffers), .. },
+            crate::MiriMachine { data_race: Some(global), threads, .. },
+        ) = this.get_alloc_extra_mut(alloc_id)?
+        {
+            if atomic == AtomicRwOrd::SeqCst {
+                global.sc_read(threads);
+                global.sc_write(threads);
+            }
+            let range = alloc_range(base_offset, place.layout.size);
+            let buffer = alloc_buffers.get_or_create_store_buffer_mut(range, init)?;
+            buffer.read_from_last_store(global, threads, atomic == AtomicRwOrd::SeqCst);
+            buffer.buffered_write(new_val, global, threads, atomic == AtomicRwOrd::SeqCst)?;
+        }
+        Ok(())
+    }
+
+    fn buffered_atomic_read(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicReadOrd,
+        latest_in_mo: Scalar<Provenance>,
+        validate: impl FnOnce() -> InterpResult<'tcx>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+        if let Some(global) = &this.machine.data_race {
+            let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr)?;
+            if let Some(alloc_buffers) = this.get_alloc_extra(alloc_id)?.weak_memory.as_ref() {
+                if atomic == AtomicReadOrd::SeqCst {
+                    global.sc_read(&this.machine.threads);
+                }
+                let mut rng = this.machine.rng.borrow_mut();
+                let buffer = alloc_buffers.get_or_create_store_buffer(
+                    alloc_range(base_offset, place.layout.size),
+                    latest_in_mo,
+                )?;
+                let (loaded, recency) = buffer.buffered_read(
+                    global,
+                    &this.machine.threads,
+                    atomic == AtomicReadOrd::SeqCst,
+                    &mut *rng,
+                    validate,
+                )?;
+                if global.track_outdated_loads && recency == LoadRecency::Outdated {
+                    this.emit_diagnostic(NonHaltingDiagnostic::WeakMemoryOutdatedLoad);
+                }
+
+                return Ok(loaded);
+            }
+        }
+
+        // Race detector or weak memory disabled, simply read the latest value
+        validate()?;
+        Ok(latest_in_mo)
+    }
+
+    fn buffered_atomic_write(
+        &mut self,
+        val: Scalar<Provenance>,
+        dest: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicWriteOrd,
+        init: Scalar<Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(dest.ptr)?;
+        if let (
+            crate::AllocExtra { weak_memory: Some(alloc_buffers), .. },
+            crate::MiriMachine { data_race: Some(global), threads, .. },
+        ) = this.get_alloc_extra_mut(alloc_id)?
+        {
+            if atomic == AtomicWriteOrd::SeqCst {
+                global.sc_write(threads);
+            }
+
+            // UGLY HACK: in write_scalar_atomic() we don't know the value before our write,
+            // so init == val always. If the buffer is fresh then we would've duplicated an entry,
+            // so we need to remove it.
+            // See https://github.com/rust-lang/miri/issues/2164
+            let was_empty = matches!(
+                alloc_buffers
+                    .store_buffers
+                    .borrow()
+                    .access_type(alloc_range(base_offset, dest.layout.size)),
+                AccessType::Empty(_)
+            );
+            let buffer = alloc_buffers
+                .get_or_create_store_buffer_mut(alloc_range(base_offset, dest.layout.size), init)?;
+            if was_empty {
+                buffer.buffer.pop_front();
+            }
+
+            buffer.buffered_write(val, global, threads, atomic == AtomicWriteOrd::SeqCst)?;
+        }
+
+        // Caller should've written to dest with the vanilla scalar write, we do nothing here
+        Ok(())
+    }
+
+    /// Caller should never need to consult the store buffer for the latest value.
+    /// This function is used exclusively for failed atomic_compare_exchange_scalar
+    /// to perform load_impl on the latest store element
+    fn perform_read_on_buffered_latest(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        atomic: AtomicReadOrd,
+        init: Scalar<Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+
+        if let Some(global) = &this.machine.data_race {
+            if atomic == AtomicReadOrd::SeqCst {
+                global.sc_read(&this.machine.threads);
+            }
+            let size = place.layout.size;
+            let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr)?;
+            if let Some(alloc_buffers) = this.get_alloc_extra(alloc_id)?.weak_memory.as_ref() {
+                let buffer = alloc_buffers
+                    .get_or_create_store_buffer(alloc_range(base_offset, size), init)?;
+                buffer.read_from_last_store(
+                    global,
+                    &this.machine.threads,
+                    atomic == AtomicReadOrd::SeqCst,
+                );
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/diagnostics.rs b/src/tools/miri/src/diagnostics.rs
new file mode 100644
index 000000000000..868c85c04a88
--- /dev/null
+++ b/src/tools/miri/src/diagnostics.rs
@@ -0,0 +1,500 @@
+use std::fmt;
+use std::num::NonZeroU64;
+
+use log::trace;
+
+use rustc_span::{source_map::DUMMY_SP, SpanData, Symbol};
+use rustc_target::abi::{Align, Size};
+
+use crate::stacked_borrows::{diagnostics::TagHistory, AccessKind};
+use crate::*;
+
+/// Details of premature program termination.
+pub enum TerminationInfo {
+    Exit(i64),
+    Abort(String),
+    UnsupportedInIsolation(String),
+    StackedBorrowsUb {
+        msg: String,
+        help: Option<String>,
+        history: Option<TagHistory>,
+    },
+    Int2PtrWithStrictProvenance,
+    Deadlock,
+    MultipleSymbolDefinitions {
+        link_name: Symbol,
+        first: SpanData,
+        first_crate: Symbol,
+        second: SpanData,
+        second_crate: Symbol,
+    },
+    SymbolShimClashing {
+        link_name: Symbol,
+        span: SpanData,
+    },
+}
+
+impl fmt::Display for TerminationInfo {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        use TerminationInfo::*;
+        match self {
+            Exit(code) => write!(f, "the evaluated program completed with exit code {code}"),
+            Abort(msg) => write!(f, "{msg}"),
+            UnsupportedInIsolation(msg) => write!(f, "{msg}"),
+            Int2PtrWithStrictProvenance =>
+                write!(
+                    f,
+                    "integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`"
+                ),
+            StackedBorrowsUb { msg, .. } => write!(f, "{msg}"),
+            Deadlock => write!(f, "the evaluated program deadlocked"),
+            MultipleSymbolDefinitions { link_name, .. } =>
+                write!(f, "multiple definitions of symbol `{link_name}`"),
+            SymbolShimClashing { link_name, .. } =>
+                write!(f, "found `{link_name}` symbol definition that clashes with a built-in shim",),
+        }
+    }
+}
+
+impl MachineStopType for TerminationInfo {}
+
+/// Miri specific diagnostics
+pub enum NonHaltingDiagnostic {
+    CreatedPointerTag(NonZeroU64, Option<(AllocId, AllocRange)>),
+    /// This `Item` was popped from the borrow stack, either due to an access with the given tag or
+    /// a deallocation when the second argument is `None`.
+    PoppedPointerTag(Item, Option<(ProvenanceExtra, AccessKind)>),
+    CreatedCallId(CallId),
+    CreatedAlloc(AllocId, Size, Align, MemoryKind<MiriMemoryKind>),
+    FreedAlloc(AllocId),
+    RejectedIsolatedOp(String),
+    ProgressReport {
+        block_count: u64, // how many basic blocks have been run so far
+    },
+    Int2Ptr {
+        details: bool,
+    },
+    WeakMemoryOutdatedLoad,
+}
+
+/// Level of Miri specific diagnostics
+enum DiagLevel {
+    Error,
+    Warning,
+    Note,
+}
+
+/// Attempts to prune a stacktrace to omit the Rust runtime, and returns a bool indicating if any
+/// frames were pruned. If the stacktrace does not have any local frames, we conclude that it must
+/// be pointing to a problem in the Rust runtime itself, and do not prune it at all.
+fn prune_stacktrace<'tcx>(
+    mut stacktrace: Vec<FrameInfo<'tcx>>,
+    machine: &MiriMachine<'_, 'tcx>,
+) -> (Vec<FrameInfo<'tcx>>, bool) {
+    match machine.backtrace_style {
+        BacktraceStyle::Off => {
+            // Remove all frames marked with `caller_location` -- that attribute indicates we
+            // usually want to point at the caller, not them.
+            stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
+            // Retain one frame so that we can print a span for the error itself
+            stacktrace.truncate(1);
+            (stacktrace, false)
+        }
+        BacktraceStyle::Short => {
+            let original_len = stacktrace.len();
+            // Only prune frames if there is at least one local frame. This check ensures that if
+            // we get a backtrace that never makes it to the user code because it has detected a
+            // bug in the Rust runtime, we don't prune away every frame.
+            let has_local_frame = stacktrace.iter().any(|frame| machine.is_local(frame));
+            if has_local_frame {
+                // Remove all frames marked with `caller_location` -- that attribute indicates we
+                // usually want to point at the caller, not them.
+                stacktrace
+                    .retain(|frame| !frame.instance.def.requires_caller_location(machine.tcx));
+
+                // This is part of the logic that `std` uses to select the relevant part of a
+                // backtrace. But here, we only look for __rust_begin_short_backtrace, not
+                // __rust_end_short_backtrace because the end symbol comes from a call to the default
+                // panic handler.
+                stacktrace = stacktrace
+                    .into_iter()
+                    .take_while(|frame| {
+                        let def_id = frame.instance.def_id();
+                        let path = machine.tcx.def_path_str(def_id);
+                        !path.contains("__rust_begin_short_backtrace")
+                    })
+                    .collect::<Vec<_>>();
+
+                // After we prune frames from the bottom, there are a few left that are part of the
+                // Rust runtime. So we remove frames until we get to a local symbol, which should be
+                // main or a test.
+                // This len check ensures that we don't somehow remove every frame, as doing so breaks
+                // the primary error message.
+                while stacktrace.len() > 1
+                    && stacktrace.last().map_or(false, |frame| !machine.is_local(frame))
+                {
+                    stacktrace.pop();
+                }
+            }
+            let was_pruned = stacktrace.len() != original_len;
+            (stacktrace, was_pruned)
+        }
+        BacktraceStyle::Full => (stacktrace, false),
+    }
+}
+
+/// Emit a custom diagnostic without going through the miri-engine machinery
+pub fn report_error<'tcx, 'mir>(
+    ecx: &InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
+    e: InterpErrorInfo<'tcx>,
+) -> Option<i64> {
+    use InterpError::*;
+
+    let mut msg = vec![];
+
+    let (title, helps) = match &e.kind() {
+        MachineStop(info) => {
+            let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
+            use TerminationInfo::*;
+            let title = match info {
+                Exit(code) => return Some(*code),
+                Abort(_) => Some("abnormal termination"),
+                UnsupportedInIsolation(_) | Int2PtrWithStrictProvenance =>
+                    Some("unsupported operation"),
+                StackedBorrowsUb { .. } => Some("Undefined Behavior"),
+                Deadlock => Some("deadlock"),
+                MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
+            };
+            #[rustfmt::skip]
+            let helps = match info {
+                UnsupportedInIsolation(_) =>
+                    vec![
+                        (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
+                        (None, format!("or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning")),
+                    ],
+                StackedBorrowsUb { help, history, .. } => {
+                    let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
+                    msg.extend(help.clone());
+                    let mut helps = vec![
+                        (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental")),
+                        (None, format!("see {url} for further information")),
+                    ];
+                    if let Some(TagHistory {created, invalidated, protected}) = history.clone() {
+                        helps.push((Some(created.1), created.0));
+                        if let Some((msg, span)) = invalidated {
+                            helps.push((Some(span), msg));
+                        }
+                        if let Some((protector_msg, protector_span)) = protected {
+                            helps.push((Some(protector_span), protector_msg));
+                        }
+                    }
+                    helps
+                }
+                MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
+                    vec![
+                        (Some(*first), format!("it's first defined here, in crate `{first_crate}`")),
+                        (Some(*second), format!("then it's defined here again, in crate `{second_crate}`")),
+                    ],
+                SymbolShimClashing { link_name, span } =>
+                    vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
+                Int2PtrWithStrictProvenance =>
+                    vec![(None, format!("use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead"))],
+                _ => vec![],
+            };
+            (title, helps)
+        }
+        _ => {
+            #[rustfmt::skip]
+            let title = match e.kind() {
+                Unsupported(_) =>
+                    "unsupported operation",
+                UndefinedBehavior(_) =>
+                    "Undefined Behavior",
+                ResourceExhaustion(_) =>
+                    "resource exhaustion",
+                InvalidProgram(
+                    InvalidProgramInfo::AlreadyReported(_) |
+                    InvalidProgramInfo::Layout(..) |
+                    InvalidProgramInfo::ReferencedConstant
+                ) =>
+                    "post-monomorphization error",
+                kind =>
+                    bug!("This error should be impossible in Miri: {kind:?}"),
+            };
+            #[rustfmt::skip]
+            let helps = match e.kind() {
+                Unsupported(
+                    UnsupportedOpInfo::ThreadLocalStatic(_) |
+                    UnsupportedOpInfo::ReadExternStatic(_) |
+                    UnsupportedOpInfo::PartialPointerOverwrite(_) | // we make memory uninit instead
+                    UnsupportedOpInfo::ReadPointerAsBytes
+                ) =>
+                    panic!("Error should never be raised by Miri: {kind:?}", kind = e.kind()),
+                Unsupported(
+                    UnsupportedOpInfo::Unsupported(_) |
+                    UnsupportedOpInfo::PartialPointerCopy(_)
+                ) =>
+                    vec![(None, format!("this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support"))],
+                UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed { .. })
+                    if ecx.machine.check_alignment == AlignmentCheck::Symbolic
+                =>
+                    vec![
+                        (None, format!("this usually indicates that your program performed an invalid operation and caused Undefined Behavior")),
+                        (None, format!("but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives")),
+                    ],
+                UndefinedBehavior(_) =>
+                    vec![
+                        (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
+                        (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
+                    ],
+                InvalidProgram(_) | ResourceExhaustion(_) | MachineStop(_) =>
+                    vec![],
+            };
+            (Some(title), helps)
+        }
+    };
+
+    let stacktrace = ecx.generate_stacktrace();
+    let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
+    e.print_backtrace();
+    msg.insert(0, e.to_string());
+    report_msg(
+        DiagLevel::Error,
+        &if let Some(title) = title { format!("{}: {}", title, msg[0]) } else { msg[0].clone() },
+        msg,
+        vec![],
+        helps,
+        &stacktrace,
+        &ecx.machine,
+    );
+
+    // Include a note like `std` does when we omit frames from a backtrace
+    if was_pruned {
+        ecx.tcx.sess.diagnostic().note_without_error(
+            "some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace",
+        );
+    }
+
+    // Debug-dump all locals.
+    for (i, frame) in ecx.active_thread_stack().iter().enumerate() {
+        trace!("-------------------");
+        trace!("Frame {}", i);
+        trace!("    return: {:?}", *frame.return_place);
+        for (i, local) in frame.locals.iter().enumerate() {
+            trace!("    local {}: {:?}", i, local.value);
+        }
+    }
+
+    // Extra output to help debug specific issues.
+    match e.kind() {
+        UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
+            eprintln!(
+                "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
+                range = access.uninit,
+            );
+            eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
+        }
+        _ => {}
+    }
+
+    None
+}
+
+/// Report an error or note (depending on the `error` argument) with the given stacktrace.
+/// Also emits a full stacktrace of the interpreter stack.
+/// We want to present a multi-line span message for some errors. Diagnostics do not support this
+/// directly, so we pass the lines as a `Vec<String>` and display each line after the first with an
+/// additional `span_label` or `note` call.
+fn report_msg<'tcx>(
+    diag_level: DiagLevel,
+    title: &str,
+    span_msg: Vec<String>,
+    notes: Vec<(Option<SpanData>, String)>,
+    helps: Vec<(Option<SpanData>, String)>,
+    stacktrace: &[FrameInfo<'tcx>],
+    machine: &MiriMachine<'_, 'tcx>,
+) {
+    let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
+    let sess = machine.tcx.sess;
+    let mut err = match diag_level {
+        DiagLevel::Error => sess.struct_span_err(span, title).forget_guarantee(),
+        DiagLevel::Warning => sess.struct_span_warn(span, title),
+        DiagLevel::Note => sess.diagnostic().span_note_diag(span, title),
+    };
+
+    // Show main message.
+    if span != DUMMY_SP {
+        for line in span_msg {
+            err.span_label(span, line);
+        }
+    } else {
+        // Make sure we show the message even when it is a dummy span.
+        for line in span_msg {
+            err.note(&line);
+        }
+        err.note("(no span available)");
+    }
+
+    // Show note and help messages.
+    for (span_data, note) in &notes {
+        if let Some(span_data) = span_data {
+            err.span_note(span_data.span(), note);
+        } else {
+            err.note(note);
+        }
+    }
+    for (span_data, help) in &helps {
+        if let Some(span_data) = span_data {
+            err.span_help(span_data.span(), help);
+        } else {
+            err.help(help);
+        }
+    }
+    if notes.len() + helps.len() > 0 {
+        // Add visual separator before backtrace.
+        err.note("BACKTRACE:");
+    }
+    // Add backtrace
+    for (idx, frame_info) in stacktrace.iter().enumerate() {
+        let is_local = machine.is_local(frame_info);
+        // No span for non-local frames and the first frame (which is the error site).
+        if is_local && idx > 0 {
+            err.span_note(frame_info.span, &frame_info.to_string());
+        } else {
+            err.note(&frame_info.to_string());
+        }
+    }
+
+    err.emit();
+}
+
+impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
+    pub fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
+        use NonHaltingDiagnostic::*;
+
+        let stacktrace =
+            MiriInterpCx::generate_stacktrace_from_stack(self.threads.active_thread_stack());
+        let (stacktrace, _was_pruned) = prune_stacktrace(stacktrace, self);
+
+        let (title, diag_level) = match e {
+            RejectedIsolatedOp(_) => ("operation rejected by isolation", DiagLevel::Warning),
+            Int2Ptr { .. } => ("integer-to-pointer cast", DiagLevel::Warning),
+            CreatedPointerTag(..)
+            | PoppedPointerTag(..)
+            | CreatedCallId(..)
+            | CreatedAlloc(..)
+            | FreedAlloc(..)
+            | ProgressReport { .. }
+            | WeakMemoryOutdatedLoad => ("tracking was triggered", DiagLevel::Note),
+        };
+
+        let msg = match e {
+            CreatedPointerTag(tag, None) => format!("created tag {tag:?}"),
+            CreatedPointerTag(tag, Some((alloc_id, range))) =>
+                format!("created tag {tag:?} at {alloc_id:?}{range:?}"),
+            PoppedPointerTag(item, tag) =>
+                match tag {
+                    None => format!("popped tracked tag for item {item:?} due to deallocation",),
+                    Some((tag, access)) => {
+                        format!(
+                            "popped tracked tag for item {item:?} due to {access:?} access for {tag:?}",
+                        )
+                    }
+                },
+            CreatedCallId(id) => format!("function call with id {id}"),
+            CreatedAlloc(AllocId(id), size, align, kind) =>
+                format!(
+                    "created {kind} allocation of {size} bytes (alignment {align} bytes) with id {id}",
+                    size = size.bytes(),
+                    align = align.bytes(),
+                ),
+            FreedAlloc(AllocId(id)) => format!("freed allocation with id {id}"),
+            RejectedIsolatedOp(ref op) =>
+                format!("{op} was made to return an error due to isolation"),
+            ProgressReport { .. } =>
+                format!("progress report: current operation being executed is here"),
+            Int2Ptr { .. } => format!("integer-to-pointer cast"),
+            WeakMemoryOutdatedLoad =>
+                format!("weak memory emulation: outdated value returned from load"),
+        };
+
+        let notes = match e {
+            ProgressReport { block_count } => {
+                // It is important that each progress report is slightly different, since
+                // identical diagnostics are being deduplicated.
+                vec![(None, format!("so far, {block_count} basic blocks have been executed"))]
+            }
+            _ => vec![],
+        };
+
+        let helps = match e {
+            Int2Ptr { details: true } =>
+                vec![
+                    (
+                        None,
+                        format!(
+                            "This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,"
+                        ),
+                    ),
+                    (
+                        None,
+                        format!("which means that Miri might miss pointer bugs in this program."),
+                    ),
+                    (
+                        None,
+                        format!(
+                            "See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation."
+                        ),
+                    ),
+                    (
+                        None,
+                        format!(
+                            "To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead."
+                        ),
+                    ),
+                    (
+                        None,
+                        format!(
+                            "You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics."
+                        ),
+                    ),
+                    (
+                        None,
+                        format!(
+                            "Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning."
+                        ),
+                    ),
+                ],
+            _ => vec![],
+        };
+
+        report_msg(diag_level, title, vec![msg], notes, helps, &stacktrace, self);
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emit_diagnostic(&self, e: NonHaltingDiagnostic) {
+        let this = self.eval_context_ref();
+        this.machine.emit_diagnostic(e);
+    }
+
+    /// We had a panic in Miri itself, try to print something useful.
+    fn handle_ice(&self) {
+        eprintln!();
+        eprintln!(
+            "Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:"
+        );
+        let this = self.eval_context_ref();
+        let stacktrace = this.generate_stacktrace();
+        report_msg(
+            DiagLevel::Note,
+            "the place in the program where the ICE was triggered",
+            vec![],
+            vec![],
+            vec![],
+            &stacktrace,
+            &this.machine,
+        );
+    }
+}
diff --git a/src/tools/miri/src/eval.rs b/src/tools/miri/src/eval.rs
new file mode 100644
index 000000000000..91a2ac13b1b1
--- /dev/null
+++ b/src/tools/miri/src/eval.rs
@@ -0,0 +1,514 @@
+//! Main evaluator loop and setting up the initial stack frame.
+
+use std::ffi::{OsStr, OsString};
+use std::iter;
+use std::panic::{self, AssertUnwindSafe};
+use std::path::PathBuf;
+use std::thread;
+
+use log::info;
+
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::def_id::DefId;
+use rustc_middle::ty::{
+    self,
+    layout::{LayoutCx, LayoutOf},
+    TyCtxt,
+};
+use rustc_target::spec::abi::Abi;
+
+use rustc_session::config::EntryFnType;
+
+use crate::*;
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum AlignmentCheck {
+    /// Do not check alignment.
+    None,
+    /// Check alignment "symbolically", i.e., using only the requested alignment for an allocation and not its real base address.
+    Symbolic,
+    /// Check alignment on the actual physical integer address.
+    Int,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum RejectOpWith {
+    /// Isolated op is rejected with an abort of the machine.
+    Abort,
+
+    /// If not Abort, miri returns an error for an isolated op.
+    /// Following options determine if user should be warned about such error.
+    /// Do not print warning about rejected isolated op.
+    NoWarning,
+
+    /// Print a warning about rejected isolated op, with backtrace.
+    Warning,
+
+    /// Print a warning about rejected isolated op, without backtrace.
+    WarningWithoutBacktrace,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum IsolatedOp {
+    /// Reject an op requiring communication with the host. By
+    /// default, miri rejects the op with an abort. If not, it returns
+    /// an error code, and prints a warning about it. Warning levels
+    /// are controlled by `RejectOpWith` enum.
+    Reject(RejectOpWith),
+
+    /// Execute op requiring communication with the host, i.e. disable isolation.
+    Allow,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub enum BacktraceStyle {
+    /// Prints a terser backtrace which ideally only contains relevant information.
+    Short,
+    /// Prints a backtrace with all possible information.
+    Full,
+    /// Prints only the frame that the error occurs in.
+    Off,
+}
+
+/// Configuration needed to spawn a Miri instance.
+#[derive(Clone)]
+pub struct MiriConfig {
+    /// The host environment snapshot to use as basis for what is provided to the interpreted program.
+    /// (This is still subject to isolation as well as `forwarded_env_vars`.)
+    pub env: Vec<(OsString, OsString)>,
+    /// Determine if validity checking is enabled.
+    pub validate: bool,
+    /// Determines if Stacked Borrows is enabled.
+    pub stacked_borrows: bool,
+    /// Controls alignment checking.
+    pub check_alignment: AlignmentCheck,
+    /// Controls function [ABI](Abi) checking.
+    pub check_abi: bool,
+    /// Action for an op requiring communication with the host.
+    pub isolated_op: IsolatedOp,
+    /// Determines if memory leaks should be ignored.
+    pub ignore_leaks: bool,
+    /// Environment variables that should always be forwarded from the host.
+    pub forwarded_env_vars: Vec<String>,
+    /// Command-line arguments passed to the interpreted program.
+    pub args: Vec<String>,
+    /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
+    pub seed: Option<u64>,
+    /// The stacked borrows pointer ids to report about
+    pub tracked_pointer_tags: FxHashSet<SbTag>,
+    /// The stacked borrows call IDs to report about
+    pub tracked_call_ids: FxHashSet<CallId>,
+    /// The allocation ids to report about.
+    pub tracked_alloc_ids: FxHashSet<AllocId>,
+    /// Determine if data race detection should be enabled
+    pub data_race_detector: bool,
+    /// Determine if weak memory emulation should be enabled. Requires data race detection to be enabled
+    pub weak_memory_emulation: bool,
+    /// Track when an outdated (weak memory) load happens.
+    pub track_outdated_loads: bool,
+    /// Rate of spurious failures for compare_exchange_weak atomic operations,
+    /// between 0.0 and 1.0, defaulting to 0.8 (80% chance of failure).
+    pub cmpxchg_weak_failure_rate: f64,
+    /// If `Some`, enable the `measureme` profiler, writing results to a file
+    /// with the specified prefix.
+    pub measureme_out: Option<String>,
+    /// Panic when unsupported functionality is encountered.
+    pub panic_on_unsupported: bool,
+    /// Which style to use for printing backtraces.
+    pub backtrace_style: BacktraceStyle,
+    /// Which provenance to use for int2ptr casts
+    pub provenance_mode: ProvenanceMode,
+    /// Whether to ignore any output by the program. This is helpful when debugging miri
+    /// as its messages don't get intermingled with the program messages.
+    pub mute_stdout_stderr: bool,
+    /// The probability of the active thread being preempted at the end of each basic block.
+    pub preemption_rate: f64,
+    /// Report the current instruction being executed every N basic blocks.
+    pub report_progress: Option<u32>,
+    /// Whether Stacked Borrows retagging should recurse into fields of datatypes.
+    pub retag_fields: bool,
+    /// The location of a shared object file to load when calling external functions
+    /// FIXME! consider allowing users to specify paths to multiple SO files, or to a directory
+    pub external_so_file: Option<PathBuf>,
+    /// Run a garbage collector for SbTags every N basic blocks.
+    pub gc_interval: u32,
+}
+
+impl Default for MiriConfig {
+    fn default() -> MiriConfig {
+        MiriConfig {
+            env: vec![],
+            validate: true,
+            stacked_borrows: true,
+            check_alignment: AlignmentCheck::Int,
+            check_abi: true,
+            isolated_op: IsolatedOp::Reject(RejectOpWith::Abort),
+            ignore_leaks: false,
+            forwarded_env_vars: vec![],
+            args: vec![],
+            seed: None,
+            tracked_pointer_tags: FxHashSet::default(),
+            tracked_call_ids: FxHashSet::default(),
+            tracked_alloc_ids: FxHashSet::default(),
+            data_race_detector: true,
+            weak_memory_emulation: true,
+            track_outdated_loads: false,
+            cmpxchg_weak_failure_rate: 0.8, // 80%
+            measureme_out: None,
+            panic_on_unsupported: false,
+            backtrace_style: BacktraceStyle::Short,
+            provenance_mode: ProvenanceMode::Default,
+            mute_stdout_stderr: false,
+            preemption_rate: 0.01, // 1%
+            report_progress: None,
+            retag_fields: false,
+            external_so_file: None,
+            gc_interval: 10_000,
+        }
+    }
+}
+
+/// Returns a freshly created `InterpCx`, along with an `MPlaceTy` representing
+/// the location where the return value of the `start` function will be
+/// written to.
+/// Public because this is also used by `priroda`.
+pub fn create_ecx<'mir, 'tcx: 'mir>(
+    tcx: TyCtxt<'tcx>,
+    entry_id: DefId,
+    entry_type: EntryFnType,
+    config: &MiriConfig,
+) -> InterpResult<'tcx, (InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>, MPlaceTy<'tcx, Provenance>)>
+{
+    let param_env = ty::ParamEnv::reveal_all();
+    let layout_cx = LayoutCx { tcx, param_env };
+    let mut ecx = InterpCx::new(
+        tcx,
+        rustc_span::source_map::DUMMY_SP,
+        param_env,
+        MiriMachine::new(config, layout_cx),
+    );
+
+    // Some parts of initialization require a full `InterpCx`.
+    MiriMachine::late_init(&mut ecx, config)?;
+
+    // Make sure we have MIR. We check MIR for some stable monomorphic function in libcore.
+    let sentinel = ecx.try_resolve_path(&["core", "ascii", "escape_default"]);
+    if !matches!(sentinel, Some(s) if tcx.is_mir_available(s.def.def_id())) {
+        tcx.sess.fatal(
+            "the current sysroot was built without `-Zalways-encode-mir`, or libcore seems missing. \
+            Use `cargo miri setup` to prepare a sysroot that is suitable for Miri."
+        );
+    }
+
+    // Setup first stack frame.
+    let entry_instance = ty::Instance::mono(tcx, entry_id);
+
+    // First argument is constructed later, because it's skipped if the entry function uses #[start].
+
+    // Second argument (argc): length of `config.args`.
+    let argc = Scalar::from_machine_usize(u64::try_from(config.args.len()).unwrap(), &ecx);
+    // Third argument (`argv`): created from `config.args`.
+    let argv = {
+        // Put each argument in memory, collect pointers.
+        let mut argvs = Vec::<Immediate<Provenance>>::new();
+        for arg in config.args.iter() {
+            // Make space for `0` terminator.
+            let size = u64::try_from(arg.len()).unwrap().checked_add(1).unwrap();
+            let arg_type = tcx.mk_array(tcx.types.u8, size);
+            let arg_place =
+                ecx.allocate(ecx.layout_of(arg_type)?, MiriMemoryKind::Machine.into())?;
+            ecx.write_os_str_to_c_str(OsStr::new(arg), arg_place.ptr, size)?;
+            ecx.mark_immutable(&arg_place);
+            argvs.push(arg_place.to_ref(&ecx));
+        }
+        // Make an array with all these pointers, in the Miri memory.
+        let argvs_layout = ecx.layout_of(
+            tcx.mk_array(tcx.mk_imm_ptr(tcx.types.u8), u64::try_from(argvs.len()).unwrap()),
+        )?;
+        let argvs_place = ecx.allocate(argvs_layout, MiriMemoryKind::Machine.into())?;
+        for (idx, arg) in argvs.into_iter().enumerate() {
+            let place = ecx.mplace_field(&argvs_place, idx)?;
+            ecx.write_immediate(arg, &place.into())?;
+        }
+        ecx.mark_immutable(&argvs_place);
+        // A pointer to that place is the 3rd argument for main.
+        let argv = argvs_place.to_ref(&ecx);
+        // Store `argc` and `argv` for macOS `_NSGetArg{c,v}`.
+        {
+            let argc_place =
+                ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
+            ecx.write_scalar(argc, &argc_place.into())?;
+            ecx.mark_immutable(&argc_place);
+            ecx.machine.argc = Some(*argc_place);
+
+            let argv_place = ecx.allocate(
+                ecx.layout_of(tcx.mk_imm_ptr(tcx.types.unit))?,
+                MiriMemoryKind::Machine.into(),
+            )?;
+            ecx.write_immediate(argv, &argv_place.into())?;
+            ecx.mark_immutable(&argv_place);
+            ecx.machine.argv = Some(*argv_place);
+        }
+        // Store command line as UTF-16 for Windows `GetCommandLineW`.
+        {
+            // Construct a command string with all the arguments.
+            let cmd_utf16: Vec<u16> = args_to_utf16_command_string(config.args.iter());
+
+            let cmd_type = tcx.mk_array(tcx.types.u16, u64::try_from(cmd_utf16.len()).unwrap());
+            let cmd_place =
+                ecx.allocate(ecx.layout_of(cmd_type)?, MiriMemoryKind::Machine.into())?;
+            ecx.machine.cmd_line = Some(*cmd_place);
+            // Store the UTF-16 string. We just allocated so we know the bounds are fine.
+            for (idx, &c) in cmd_utf16.iter().enumerate() {
+                let place = ecx.mplace_field(&cmd_place, idx)?;
+                ecx.write_scalar(Scalar::from_u16(c), &place.into())?;
+            }
+            ecx.mark_immutable(&cmd_place);
+        }
+        argv
+    };
+
+    // Return place (in static memory so that it does not count as leak).
+    let ret_place = ecx.allocate(ecx.machine.layouts.isize, MiriMemoryKind::Machine.into())?;
+    // Call start function.
+
+    match entry_type {
+        EntryFnType::Main { .. } => {
+            let start_id = tcx.lang_items().start_fn().unwrap();
+            let main_ret_ty = tcx.fn_sig(entry_id).output();
+            let main_ret_ty = main_ret_ty.no_bound_vars().unwrap();
+            let start_instance = ty::Instance::resolve(
+                tcx,
+                ty::ParamEnv::reveal_all(),
+                start_id,
+                tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
+            )
+            .unwrap()
+            .unwrap();
+
+            let main_ptr = ecx.create_fn_alloc_ptr(FnVal::Instance(entry_instance));
+
+            // Inlining of `DEFAULT` from
+            // https://github.com/rust-lang/rust/blob/master/compiler/rustc_session/src/config/sigpipe.rs.
+            // Alaways using DEFAULT is okay since we don't support signals in Miri anyway.
+            let sigpipe = 2;
+
+            ecx.call_function(
+                start_instance,
+                Abi::Rust,
+                &[
+                    Scalar::from_pointer(main_ptr, &ecx).into(),
+                    argc.into(),
+                    argv,
+                    Scalar::from_u8(sigpipe).into(),
+                ],
+                Some(&ret_place.into()),
+                StackPopCleanup::Root { cleanup: true },
+            )?;
+        }
+        EntryFnType::Start => {
+            ecx.call_function(
+                entry_instance,
+                Abi::Rust,
+                &[argc.into(), argv],
+                Some(&ret_place.into()),
+                StackPopCleanup::Root { cleanup: true },
+            )?;
+        }
+    }
+
+    Ok((ecx, ret_place))
+}
+
+/// Evaluates the entry function specified by `entry_id`.
+/// Returns `Some(return_code)` if program executed completed.
+/// Returns `None` if an evaluation error occurred.
+#[allow(clippy::needless_lifetimes)]
+pub fn eval_entry<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    entry_id: DefId,
+    entry_type: EntryFnType,
+    config: MiriConfig,
+) -> Option<i64> {
+    // Copy setting before we move `config`.
+    let ignore_leaks = config.ignore_leaks;
+
+    let (mut ecx, ret_place) = match create_ecx(tcx, entry_id, entry_type, &config) {
+        Ok(v) => v,
+        Err(err) => {
+            err.print_backtrace();
+            panic!("Miri initialization error: {}", err.kind())
+        }
+    };
+
+    // Perform the main execution.
+    let res: thread::Result<InterpResult<'_, i64>> = panic::catch_unwind(AssertUnwindSafe(|| {
+        // Main loop.
+        loop {
+            match ecx.schedule()? {
+                SchedulingAction::ExecuteStep => {
+                    assert!(ecx.step()?, "a terminated thread was scheduled for execution");
+                }
+                SchedulingAction::ExecuteTimeoutCallback => {
+                    ecx.run_timeout_callback()?;
+                }
+                SchedulingAction::ExecuteDtors => {
+                    // This will either enable the thread again (so we go back
+                    // to `ExecuteStep`), or determine that this thread is done
+                    // for good.
+                    ecx.schedule_next_tls_dtor_for_active_thread()?;
+                }
+                SchedulingAction::Stop => {
+                    break;
+                }
+            }
+        }
+        let return_code = ecx.read_scalar(&ret_place.into())?.to_machine_isize(&ecx)?;
+        Ok(return_code)
+    }));
+    let res = res.unwrap_or_else(|panic_payload| {
+        ecx.handle_ice();
+        panic::resume_unwind(panic_payload)
+    });
+
+    // Machine cleanup. Only do this if all threads have terminated; threads that are still running
+    // might cause Stacked Borrows errors (https://github.com/rust-lang/miri/issues/2396).
+    if ecx.have_all_terminated() {
+        // Even if all threads have terminated, we have to beware of data races since some threads
+        // might not have joined the main thread (https://github.com/rust-lang/miri/issues/2020,
+        // https://github.com/rust-lang/miri/issues/2508).
+        ecx.allow_data_races_all_threads_done();
+        EnvVars::cleanup(&mut ecx).expect("error during env var cleanup");
+    }
+
+    // Process the result.
+    match res {
+        Ok(return_code) => {
+            if !ignore_leaks {
+                // Check for thread leaks.
+                if !ecx.have_all_terminated() {
+                    tcx.sess.err(
+                        "the main thread terminated without waiting for all remaining threads",
+                    );
+                    tcx.sess.note_without_error("pass `-Zmiri-ignore-leaks` to disable this check");
+                    return None;
+                }
+                // Check for memory leaks.
+                info!("Additonal static roots: {:?}", ecx.machine.static_roots);
+                let leaks = ecx.leak_report(&ecx.machine.static_roots);
+                if leaks != 0 {
+                    tcx.sess.err("the evaluated program leaked memory");
+                    tcx.sess.note_without_error("pass `-Zmiri-ignore-leaks` to disable this check");
+                    // Ignore the provided return code - let the reported error
+                    // determine the return code.
+                    return None;
+                }
+            }
+            Some(return_code)
+        }
+        Err(e) => report_error(&ecx, e),
+    }
+}
+
+/// Turns an array of arguments into a Windows command line string.
+///
+/// The string will be UTF-16 encoded and NUL terminated.
+///
+/// Panics if the zeroth argument contains the `"` character because doublequotes
+/// in `argv[0]` cannot be encoded using the standard command line parsing rules.
+///
+/// Further reading:
+/// * [Parsing C++ command-line arguments](https://docs.microsoft.com/en-us/cpp/cpp/main-function-command-line-args?view=msvc-160#parsing-c-command-line-arguments)
+/// * [The C/C++ Parameter Parsing Rules](https://daviddeley.com/autohotkey/parameters/parameters.htm#WINCRULES)
+fn args_to_utf16_command_string<I, T>(mut args: I) -> Vec<u16>
+where
+    I: Iterator<Item = T>,
+    T: AsRef<str>,
+{
+    // Parse argv[0]. Slashes aren't escaped. Literal double quotes are not allowed.
+    let mut cmd = {
+        let arg0 = if let Some(arg0) = args.next() {
+            arg0
+        } else {
+            return vec![0];
+        };
+        let arg0 = arg0.as_ref();
+        if arg0.contains('"') {
+            panic!("argv[0] cannot contain a doublequote (\") character");
+        } else {
+            // Always surround argv[0] with quotes.
+            let mut s = String::new();
+            s.push('"');
+            s.push_str(arg0);
+            s.push('"');
+            s
+        }
+    };
+
+    // Build the other arguments.
+    for arg in args {
+        let arg = arg.as_ref();
+        cmd.push(' ');
+        if arg.is_empty() {
+            cmd.push_str("\"\"");
+        } else if !arg.bytes().any(|c| matches!(c, b'"' | b'\t' | b' ')) {
+            // No quote, tab, or space -- no escaping required.
+            cmd.push_str(arg);
+        } else {
+            // Spaces and tabs are escaped by surrounding them in quotes.
+            // Quotes are themselves escaped by using backslashes when in a
+            // quoted block.
+            // Backslashes only need to be escaped when one or more are directly
+            // followed by a quote. Otherwise they are taken literally.
+
+            cmd.push('"');
+            let mut chars = arg.chars().peekable();
+            loop {
+                let mut nslashes = 0;
+                while let Some(&'\\') = chars.peek() {
+                    chars.next();
+                    nslashes += 1;
+                }
+
+                match chars.next() {
+                    Some('"') => {
+                        cmd.extend(iter::repeat('\\').take(nslashes * 2 + 1));
+                        cmd.push('"');
+                    }
+                    Some(c) => {
+                        cmd.extend(iter::repeat('\\').take(nslashes));
+                        cmd.push(c);
+                    }
+                    None => {
+                        cmd.extend(iter::repeat('\\').take(nslashes * 2));
+                        break;
+                    }
+                }
+            }
+            cmd.push('"');
+        }
+    }
+
+    if cmd.contains('\0') {
+        panic!("interior null in command line arguments");
+    }
+    cmd.encode_utf16().chain(iter::once(0)).collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    #[should_panic(expected = "argv[0] cannot contain a doublequote (\") character")]
+    fn windows_argv0_panic_on_quote() {
+        args_to_utf16_command_string(["\""].iter());
+    }
+    #[test]
+    fn windows_argv0_no_escape() {
+        // Ensure that a trailing backslash in argv[0] is not escaped.
+        let cmd = String::from_utf16_lossy(&args_to_utf16_command_string(
+            [r"C:\Program Files\", "arg1", "arg 2", "arg \" 3"].iter(),
+        ));
+        assert_eq!(cmd.trim_end_matches('\0'), r#""C:\Program Files\" arg1 "arg 2" "arg \" 3""#);
+    }
+}
diff --git a/src/tools/miri/src/helpers.rs b/src/tools/miri/src/helpers.rs
new file mode 100644
index 000000000000..0f0bfa355bdc
--- /dev/null
+++ b/src/tools/miri/src/helpers.rs
@@ -0,0 +1,1004 @@
+pub mod convert;
+
+use std::mem;
+use std::num::NonZeroUsize;
+use std::time::Duration;
+
+use log::trace;
+
+use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
+use rustc_middle::mir;
+use rustc_middle::ty::{
+    self,
+    layout::{LayoutOf, TyAndLayout},
+    List, TyCtxt,
+};
+use rustc_span::{def_id::CrateNum, sym, Span, Symbol};
+use rustc_target::abi::{Align, FieldsShape, Size, Variants};
+use rustc_target::spec::abi::Abi;
+
+use rand::RngCore;
+
+use crate::*;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+
+// This mapping should match `decode_error_kind` in
+// <https://github.com/rust-lang/rust/blob/master/library/std/src/sys/unix/mod.rs>.
+const UNIX_IO_ERROR_TABLE: &[(&str, std::io::ErrorKind)] = {
+    use std::io::ErrorKind::*;
+    &[
+        ("E2BIG", ArgumentListTooLong),
+        ("EADDRINUSE", AddrInUse),
+        ("EADDRNOTAVAIL", AddrNotAvailable),
+        ("EBUSY", ResourceBusy),
+        ("ECONNABORTED", ConnectionAborted),
+        ("ECONNREFUSED", ConnectionRefused),
+        ("ECONNRESET", ConnectionReset),
+        ("EDEADLK", Deadlock),
+        ("EDQUOT", FilesystemQuotaExceeded),
+        ("EEXIST", AlreadyExists),
+        ("EFBIG", FileTooLarge),
+        ("EHOSTUNREACH", HostUnreachable),
+        ("EINTR", Interrupted),
+        ("EINVAL", InvalidInput),
+        ("EISDIR", IsADirectory),
+        ("ELOOP", FilesystemLoop),
+        ("ENOENT", NotFound),
+        ("ENOMEM", OutOfMemory),
+        ("ENOSPC", StorageFull),
+        ("ENOSYS", Unsupported),
+        ("EMLINK", TooManyLinks),
+        ("ENAMETOOLONG", InvalidFilename),
+        ("ENETDOWN", NetworkDown),
+        ("ENETUNREACH", NetworkUnreachable),
+        ("ENOTCONN", NotConnected),
+        ("ENOTDIR", NotADirectory),
+        ("ENOTEMPTY", DirectoryNotEmpty),
+        ("EPIPE", BrokenPipe),
+        ("EROFS", ReadOnlyFilesystem),
+        ("ESPIPE", NotSeekable),
+        ("ESTALE", StaleNetworkFileHandle),
+        ("ETIMEDOUT", TimedOut),
+        ("ETXTBSY", ExecutableFileBusy),
+        ("EXDEV", CrossesDevices),
+        // The following have two valid options. We have both for the forwards mapping; only the
+        // first one will be used for the backwards mapping.
+        ("EPERM", PermissionDenied),
+        ("EACCES", PermissionDenied),
+        ("EWOULDBLOCK", WouldBlock),
+        ("EAGAIN", WouldBlock),
+    ]
+};
+
+/// Gets an instance for a path.
+fn try_resolve_did<'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option<DefId> {
+    tcx.crates(()).iter().find(|&&krate| tcx.crate_name(krate).as_str() == path[0]).and_then(
+        |krate| {
+            let krate = DefId { krate: *krate, index: CRATE_DEF_INDEX };
+            let mut items = tcx.module_children(krate);
+            let mut path_it = path.iter().skip(1).peekable();
+
+            while let Some(segment) = path_it.next() {
+                for item in mem::take(&mut items).iter() {
+                    if item.ident.name.as_str() == *segment {
+                        if path_it.peek().is_none() {
+                            return Some(item.res.def_id());
+                        }
+
+                        items = tcx.module_children(item.res.def_id());
+                        break;
+                    }
+                }
+            }
+            None
+        },
+    )
+}
+
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Gets an instance for a path; fails gracefully if the path does not exist.
+    fn try_resolve_path(&self, path: &[&str]) -> Option<ty::Instance<'tcx>> {
+        let did = try_resolve_did(self.eval_context_ref().tcx.tcx, path)?;
+        Some(ty::Instance::mono(self.eval_context_ref().tcx.tcx, did))
+    }
+
+    /// Gets an instance for a path.
+    fn resolve_path(&self, path: &[&str]) -> ty::Instance<'tcx> {
+        self.try_resolve_path(path)
+            .unwrap_or_else(|| panic!("failed to find required Rust item: {:?}", path))
+    }
+
+    /// Evaluates the scalar at the specified path. Returns Some(val)
+    /// if the path could be resolved, and None otherwise
+    fn eval_path_scalar(&self, path: &[&str]) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+        let instance = this.resolve_path(path);
+        let cid = GlobalId { instance, promoted: None };
+        let const_val = this.eval_to_allocation(cid)?;
+        this.read_scalar(&const_val.into())
+    }
+
+    /// Helper function to get a `libc` constant as a `Scalar`.
+    fn eval_libc(&self, name: &str) -> InterpResult<'tcx, Scalar<Provenance>> {
+        self.eval_path_scalar(&["libc", name])
+    }
+
+    /// Helper function to get a `libc` constant as an `i32`.
+    fn eval_libc_i32(&self, name: &str) -> InterpResult<'tcx, i32> {
+        // TODO: Cache the result.
+        self.eval_libc(name)?.to_i32()
+    }
+
+    /// Helper function to get a `windows` constant as a `Scalar`.
+    fn eval_windows(&self, module: &str, name: &str) -> InterpResult<'tcx, Scalar<Provenance>> {
+        self.eval_context_ref().eval_path_scalar(&["std", "sys", "windows", module, name])
+    }
+
+    /// Helper function to get a `windows` constant as a `u64`.
+    fn eval_windows_u64(&self, module: &str, name: &str) -> InterpResult<'tcx, u64> {
+        // TODO: Cache the result.
+        self.eval_windows(module, name)?.to_u64()
+    }
+
+    /// Helper function to get the `TyAndLayout` of a `libc` type
+    fn libc_ty_layout(&self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
+        let this = self.eval_context_ref();
+        let ty = this.resolve_path(&["libc", name]).ty(*this.tcx, ty::ParamEnv::reveal_all());
+        this.layout_of(ty)
+    }
+
+    /// Helper function to get the `TyAndLayout` of a `windows` type
+    fn windows_ty_layout(&self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
+        let this = self.eval_context_ref();
+        let ty = this
+            .resolve_path(&["std", "sys", "windows", "c", name])
+            .ty(*this.tcx, ty::ParamEnv::reveal_all());
+        this.layout_of(ty)
+    }
+
+    /// Project to the given *named* field of the mplace (which must be a struct or union type).
+    fn mplace_field_named(
+        &self,
+        mplace: &MPlaceTy<'tcx, Provenance>,
+        name: &str,
+    ) -> InterpResult<'tcx, MPlaceTy<'tcx, Provenance>> {
+        let this = self.eval_context_ref();
+        let adt = mplace.layout.ty.ty_adt_def().unwrap();
+        for (idx, field) in adt.non_enum_variant().fields.iter().enumerate() {
+            if field.name.as_str() == name {
+                return this.mplace_field(mplace, idx);
+            }
+        }
+        bug!("No field named {} in type {}", name, mplace.layout.ty);
+    }
+
+    /// Write an int of the appropriate size to `dest`. The target type may be signed or unsigned,
+    /// we try to do the right thing anyway. `i128` can fit all integer types except for `u128` so
+    /// this method is fine for almost all integer types.
+    fn write_int(
+        &mut self,
+        i: impl Into<i128>,
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        assert!(dest.layout.abi.is_scalar(), "write_int on non-scalar type {}", dest.layout.ty);
+        let val = if dest.layout.abi.is_signed() {
+            Scalar::from_int(i, dest.layout.size)
+        } else {
+            Scalar::from_uint(u64::try_from(i.into()).unwrap(), dest.layout.size)
+        };
+        self.eval_context_mut().write_scalar(val, dest)
+    }
+
+    /// Write the first N fields of the given place.
+    fn write_int_fields(
+        &mut self,
+        values: &[i128],
+        dest: &MPlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        for (idx, &val) in values.iter().enumerate() {
+            let field = this.mplace_field(dest, idx)?;
+            this.write_int(val, &field.into())?;
+        }
+        Ok(())
+    }
+
+    /// Write the given fields of the given place.
+    fn write_int_fields_named(
+        &mut self,
+        values: &[(&str, i128)],
+        dest: &MPlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        for &(name, val) in values.iter() {
+            let field = this.mplace_field_named(dest, name)?;
+            this.write_int(val, &field.into())?;
+        }
+        Ok(())
+    }
+
+    /// Write a 0 of the appropriate size to `dest`.
+    fn write_null(&mut self, dest: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        self.write_int(0, dest)
+    }
+
+    /// Test if this pointer equals 0.
+    fn ptr_is_null(&self, ptr: Pointer<Option<Provenance>>) -> InterpResult<'tcx, bool> {
+        Ok(ptr.addr().bytes() == 0)
+    }
+
+    /// Get the `Place` for a local
+    fn local_place(&mut self, local: mir::Local) -> InterpResult<'tcx, PlaceTy<'tcx, Provenance>> {
+        let this = self.eval_context_mut();
+        let place = mir::Place { local, projection: List::empty() };
+        this.eval_place(place)
+    }
+
+    /// Generate some random bytes, and write them to `dest`.
+    fn gen_random(&mut self, ptr: Pointer<Option<Provenance>>, len: u64) -> InterpResult<'tcx> {
+        // Some programs pass in a null pointer and a length of 0
+        // to their platform's random-generation function (e.g. getrandom())
+        // on Linux. For compatibility with these programs, we don't perform
+        // any additional checks - it's okay if the pointer is invalid,
+        // since we wouldn't actually be writing to it.
+        if len == 0 {
+            return Ok(());
+        }
+        let this = self.eval_context_mut();
+
+        let mut data = vec![0; usize::try_from(len).unwrap()];
+
+        if this.machine.communicate() {
+            // Fill the buffer using the host's rng.
+            getrandom::getrandom(&mut data)
+                .map_err(|err| err_unsup_format!("host getrandom failed: {}", err))?;
+        } else {
+            let rng = this.machine.rng.get_mut();
+            rng.fill_bytes(&mut data);
+        }
+
+        this.write_bytes_ptr(ptr, data.iter().copied())
+    }
+
+    /// Call a function: Push the stack frame and pass the arguments.
+    /// For now, arguments must be scalars (so that the caller does not have to know the layout).
+    ///
+    /// If you do not provie a return place, a dangling zero-sized place will be created
+    /// for your convenience.
+    fn call_function(
+        &mut self,
+        f: ty::Instance<'tcx>,
+        caller_abi: Abi,
+        args: &[Immediate<Provenance>],
+        dest: Option<&PlaceTy<'tcx, Provenance>>,
+        stack_pop: StackPopCleanup,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let param_env = ty::ParamEnv::reveal_all(); // in Miri this is always the param_env we use... and this.param_env is private.
+        let callee_abi = f.ty(*this.tcx, param_env).fn_sig(*this.tcx).abi();
+        if this.machine.enforce_abi && callee_abi != caller_abi {
+            throw_ub_format!(
+                "calling a function with ABI {} using caller ABI {}",
+                callee_abi.name(),
+                caller_abi.name()
+            )
+        }
+
+        // Push frame.
+        let mir = this.load_mir(f.def, None)?;
+        let dest = match dest {
+            Some(dest) => dest.clone(),
+            None => MPlaceTy::fake_alloc_zst(this.layout_of(mir.return_ty())?).into(),
+        };
+        this.push_stack_frame(f, mir, &dest, stack_pop)?;
+
+        // Initialize arguments.
+        let mut callee_args = this.frame().body.args_iter();
+        for arg in args {
+            let callee_arg = this.local_place(
+                callee_args
+                    .next()
+                    .ok_or_else(|| err_ub_format!("callee has fewer arguments than expected"))?,
+            )?;
+            this.write_immediate(*arg, &callee_arg)?;
+        }
+        if callee_args.next().is_some() {
+            throw_ub_format!("callee has more arguments than expected");
+        }
+
+        Ok(())
+    }
+
+    /// Visits the memory covered by `place`, sensitive to freezing: the 2nd parameter
+    /// of `action` will be true if this is frozen, false if this is in an `UnsafeCell`.
+    /// The range is relative to `place`.
+    fn visit_freeze_sensitive(
+        &self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        size: Size,
+        mut action: impl FnMut(AllocRange, bool) -> InterpResult<'tcx>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+        trace!("visit_frozen(place={:?}, size={:?})", *place, size);
+        debug_assert_eq!(
+            size,
+            this.size_and_align_of_mplace(place)?
+                .map(|(size, _)| size)
+                .unwrap_or_else(|| place.layout.size)
+        );
+        // Store how far we proceeded into the place so far. Everything to the left of
+        // this offset has already been handled, in the sense that the frozen parts
+        // have had `action` called on them.
+        let start_addr = place.ptr.addr();
+        let mut cur_addr = start_addr;
+        // Called when we detected an `UnsafeCell` at the given offset and size.
+        // Calls `action` and advances `cur_ptr`.
+        let mut unsafe_cell_action = |unsafe_cell_ptr: &Pointer<Option<Provenance>>,
+                                      unsafe_cell_size: Size| {
+            // We assume that we are given the fields in increasing offset order,
+            // and nothing else changes.
+            let unsafe_cell_addr = unsafe_cell_ptr.addr();
+            assert!(unsafe_cell_addr >= cur_addr);
+            let frozen_size = unsafe_cell_addr - cur_addr;
+            // Everything between the cur_ptr and this `UnsafeCell` is frozen.
+            if frozen_size != Size::ZERO {
+                action(alloc_range(cur_addr - start_addr, frozen_size), /*frozen*/ true)?;
+            }
+            cur_addr += frozen_size;
+            // This `UnsafeCell` is NOT frozen.
+            if unsafe_cell_size != Size::ZERO {
+                action(
+                    alloc_range(cur_addr - start_addr, unsafe_cell_size),
+                    /*frozen*/ false,
+                )?;
+            }
+            cur_addr += unsafe_cell_size;
+            // Done
+            Ok(())
+        };
+        // Run a visitor
+        {
+            let mut visitor = UnsafeCellVisitor {
+                ecx: this,
+                unsafe_cell_action: |place| {
+                    trace!("unsafe_cell_action on {:?}", place.ptr);
+                    // We need a size to go on.
+                    let unsafe_cell_size = this
+                        .size_and_align_of_mplace(place)?
+                        .map(|(size, _)| size)
+                        // for extern types, just cover what we can
+                        .unwrap_or_else(|| place.layout.size);
+                    // Now handle this `UnsafeCell`, unless it is empty.
+                    if unsafe_cell_size != Size::ZERO {
+                        unsafe_cell_action(&place.ptr, unsafe_cell_size)
+                    } else {
+                        Ok(())
+                    }
+                },
+            };
+            visitor.visit_value(place)?;
+        }
+        // The part between the end_ptr and the end of the place is also frozen.
+        // So pretend there is a 0-sized `UnsafeCell` at the end.
+        unsafe_cell_action(&place.ptr.offset(size, this)?, Size::ZERO)?;
+        // Done!
+        return Ok(());
+
+        /// Visiting the memory covered by a `MemPlace`, being aware of
+        /// whether we are inside an `UnsafeCell` or not.
+        struct UnsafeCellVisitor<'ecx, 'mir, 'tcx, F>
+        where
+            F: FnMut(&MPlaceTy<'tcx, Provenance>) -> InterpResult<'tcx>,
+        {
+            ecx: &'ecx MiriInterpCx<'mir, 'tcx>,
+            unsafe_cell_action: F,
+        }
+
+        impl<'ecx, 'mir, 'tcx: 'mir, F> ValueVisitor<'mir, 'tcx, MiriMachine<'mir, 'tcx>>
+            for UnsafeCellVisitor<'ecx, 'mir, 'tcx, F>
+        where
+            F: FnMut(&MPlaceTy<'tcx, Provenance>) -> InterpResult<'tcx>,
+        {
+            type V = MPlaceTy<'tcx, Provenance>;
+
+            #[inline(always)]
+            fn ecx(&self) -> &MiriInterpCx<'mir, 'tcx> {
+                self.ecx
+            }
+
+            // Hook to detect `UnsafeCell`.
+            fn visit_value(&mut self, v: &MPlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+                trace!("UnsafeCellVisitor: {:?} {:?}", *v, v.layout.ty);
+                let is_unsafe_cell = match v.layout.ty.kind() {
+                    ty::Adt(adt, _) =>
+                        Some(adt.did()) == self.ecx.tcx.lang_items().unsafe_cell_type(),
+                    _ => false,
+                };
+                if is_unsafe_cell {
+                    // We do not have to recurse further, this is an `UnsafeCell`.
+                    (self.unsafe_cell_action)(v)
+                } else if self.ecx.type_is_freeze(v.layout.ty) {
+                    // This is `Freeze`, there cannot be an `UnsafeCell`
+                    Ok(())
+                } else if matches!(v.layout.fields, FieldsShape::Union(..)) {
+                    // A (non-frozen) union. We fall back to whatever the type says.
+                    (self.unsafe_cell_action)(v)
+                } else {
+                    // We want to not actually read from memory for this visit. So, before
+                    // walking this value, we have to make sure it is not a
+                    // `Variants::Multiple`.
+                    match v.layout.variants {
+                        Variants::Multiple { .. } => {
+                            // A multi-variant enum, or generator, or so.
+                            // Treat this like a union: without reading from memory,
+                            // we cannot determine the variant we are in. Reading from
+                            // memory would be subject to Stacked Borrows rules, leading
+                            // to all sorts of "funny" recursion.
+                            // We only end up here if the type is *not* freeze, so we just call the
+                            // `UnsafeCell` action.
+                            (self.unsafe_cell_action)(v)
+                        }
+                        Variants::Single { .. } => {
+                            // Proceed further, try to find where exactly that `UnsafeCell`
+                            // is hiding.
+                            self.walk_value(v)
+                        }
+                    }
+                }
+            }
+
+            // Make sure we visit aggregrates in increasing offset order.
+            fn visit_aggregate(
+                &mut self,
+                place: &MPlaceTy<'tcx, Provenance>,
+                fields: impl Iterator<Item = InterpResult<'tcx, MPlaceTy<'tcx, Provenance>>>,
+            ) -> InterpResult<'tcx> {
+                match place.layout.fields {
+                    FieldsShape::Array { .. } => {
+                        // For the array layout, we know the iterator will yield sorted elements so
+                        // we can avoid the allocation.
+                        self.walk_aggregate(place, fields)
+                    }
+                    FieldsShape::Arbitrary { .. } => {
+                        // Gather the subplaces and sort them before visiting.
+                        let mut places = fields
+                            .collect::<InterpResult<'tcx, Vec<MPlaceTy<'tcx, Provenance>>>>()?;
+                        // we just compare offsets, the abs. value never matters
+                        places.sort_by_key(|place| place.ptr.addr());
+                        self.walk_aggregate(place, places.into_iter().map(Ok))
+                    }
+                    FieldsShape::Union { .. } | FieldsShape::Primitive => {
+                        // Uh, what?
+                        bug!("unions/primitives are not aggregates we should ever visit")
+                    }
+                }
+            }
+
+            fn visit_union(
+                &mut self,
+                _v: &MPlaceTy<'tcx, Provenance>,
+                _fields: NonZeroUsize,
+            ) -> InterpResult<'tcx> {
+                bug!("we should have already handled unions in `visit_value`")
+            }
+        }
+    }
+
+    /// Helper function used inside the shims of foreign functions to check that isolation is
+    /// disabled. It returns an error using the `name` of the foreign function if this is not the
+    /// case.
+    fn check_no_isolation(&self, name: &str) -> InterpResult<'tcx> {
+        if !self.eval_context_ref().machine.communicate() {
+            self.reject_in_isolation(name, RejectOpWith::Abort)?;
+        }
+        Ok(())
+    }
+
+    /// Helper function used inside the shims of foreign functions which reject the op
+    /// when isolation is enabled. It is used to print a warning/backtrace about the rejection.
+    fn reject_in_isolation(&self, op_name: &str, reject_with: RejectOpWith) -> InterpResult<'tcx> {
+        let this = self.eval_context_ref();
+        match reject_with {
+            RejectOpWith::Abort => isolation_abort_error(op_name),
+            RejectOpWith::WarningWithoutBacktrace => {
+                this.tcx
+                    .sess
+                    .warn(&format!("{} was made to return an error due to isolation", op_name));
+                Ok(())
+            }
+            RejectOpWith::Warning => {
+                this.emit_diagnostic(NonHaltingDiagnostic::RejectedIsolatedOp(op_name.to_string()));
+                Ok(())
+            }
+            RejectOpWith::NoWarning => Ok(()), // no warning
+        }
+    }
+
+    /// Helper function used inside the shims of foreign functions to assert that the target OS
+    /// is `target_os`. It panics showing a message with the `name` of the foreign function
+    /// if this is not the case.
+    fn assert_target_os(&self, target_os: &str, name: &str) {
+        assert_eq!(
+            self.eval_context_ref().tcx.sess.target.os,
+            target_os,
+            "`{}` is only available on the `{}` target OS",
+            name,
+            target_os,
+        )
+    }
+
+    /// Helper function used inside the shims of foreign functions to assert that the target OS
+    /// is part of the UNIX family. It panics showing a message with the `name` of the foreign function
+    /// if this is not the case.
+    fn assert_target_os_is_unix(&self, name: &str) {
+        assert!(
+            target_os_is_unix(self.eval_context_ref().tcx.sess.target.os.as_ref()),
+            "`{}` is only available for supported UNIX family targets",
+            name,
+        );
+    }
+
+    /// Get last error variable as a place, lazily allocating thread-local storage for it if
+    /// necessary.
+    fn last_error_place(&mut self) -> InterpResult<'tcx, MPlaceTy<'tcx, Provenance>> {
+        let this = self.eval_context_mut();
+        if let Some(errno_place) = this.active_thread_ref().last_error {
+            Ok(errno_place)
+        } else {
+            // Allocate new place, set initial value to 0.
+            let errno_layout = this.machine.layouts.u32;
+            let errno_place = this.allocate(errno_layout, MiriMemoryKind::Machine.into())?;
+            this.write_scalar(Scalar::from_u32(0), &errno_place.into())?;
+            this.active_thread_mut().last_error = Some(errno_place);
+            Ok(errno_place)
+        }
+    }
+
+    /// Sets the last error variable.
+    fn set_last_error(&mut self, scalar: Scalar<Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let errno_place = this.last_error_place()?;
+        this.write_scalar(scalar, &errno_place.into())
+    }
+
+    /// Gets the last error variable.
+    fn get_last_error(&mut self) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+        let errno_place = this.last_error_place()?;
+        this.read_scalar(&errno_place.into())
+    }
+
+    /// This function tries to produce the most similar OS error from the `std::io::ErrorKind`
+    /// as a platform-specific errnum.
+    fn io_error_to_errnum(
+        &self,
+        err_kind: std::io::ErrorKind,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+        let target = &this.tcx.sess.target;
+        if target.families.iter().any(|f| f == "unix") {
+            for &(name, kind) in UNIX_IO_ERROR_TABLE {
+                if err_kind == kind {
+                    return this.eval_libc(name);
+                }
+            }
+            throw_unsup_format!("io error {:?} cannot be translated into a raw os error", err_kind)
+        } else if target.families.iter().any(|f| f == "windows") {
+            // FIXME: we have to finish implementing the Windows equivalent of this.
+            use std::io::ErrorKind::*;
+            this.eval_windows(
+                "c",
+                match err_kind {
+                    NotFound => "ERROR_FILE_NOT_FOUND",
+                    PermissionDenied => "ERROR_ACCESS_DENIED",
+                    _ =>
+                        throw_unsup_format!(
+                            "io error {:?} cannot be translated into a raw os error",
+                            err_kind
+                        ),
+                },
+            )
+        } else {
+            throw_unsup_format!(
+                "converting io::Error into errnum is unsupported for OS {}",
+                target.os
+            )
+        }
+    }
+
+    /// The inverse of `io_error_to_errnum`.
+    #[allow(clippy::needless_return)]
+    fn try_errnum_to_io_error(
+        &self,
+        errnum: Scalar<Provenance>,
+    ) -> InterpResult<'tcx, Option<std::io::ErrorKind>> {
+        let this = self.eval_context_ref();
+        let target = &this.tcx.sess.target;
+        if target.families.iter().any(|f| f == "unix") {
+            let errnum = errnum.to_i32()?;
+            for &(name, kind) in UNIX_IO_ERROR_TABLE {
+                if errnum == this.eval_libc_i32(name)? {
+                    return Ok(Some(kind));
+                }
+            }
+            // Our table is as complete as the mapping in std, so we are okay with saying "that's a
+            // strange one" here.
+            return Ok(None);
+        } else {
+            throw_unsup_format!(
+                "converting errnum into io::Error is unsupported for OS {}",
+                target.os
+            )
+        }
+    }
+
+    /// Sets the last OS error using a `std::io::ErrorKind`.
+    fn set_last_error_from_io_error(&mut self, err_kind: std::io::ErrorKind) -> InterpResult<'tcx> {
+        self.set_last_error(self.io_error_to_errnum(err_kind)?)
+    }
+
+    /// Helper function that consumes an `std::io::Result<T>` and returns an
+    /// `InterpResult<'tcx,T>::Ok` instead. In case the result is an error, this function returns
+    /// `Ok(-1)` and sets the last OS error accordingly.
+    ///
+    /// This function uses `T: From<i32>` instead of `i32` directly because some IO related
+    /// functions return different integer types (like `read`, that returns an `i64`).
+    fn try_unwrap_io_result<T: From<i32>>(
+        &mut self,
+        result: std::io::Result<T>,
+    ) -> InterpResult<'tcx, T> {
+        match result {
+            Ok(ok) => Ok(ok),
+            Err(e) => {
+                self.eval_context_mut().set_last_error_from_io_error(e.kind())?;
+                Ok((-1).into())
+            }
+        }
+    }
+
+    /// Calculates the MPlaceTy given the offset and layout of an access on an operand
+    fn deref_operand_and_offset(
+        &self,
+        op: &OpTy<'tcx, Provenance>,
+        offset: u64,
+        layout: TyAndLayout<'tcx>,
+    ) -> InterpResult<'tcx, MPlaceTy<'tcx, Provenance>> {
+        let this = self.eval_context_ref();
+        let op_place = this.deref_operand(op)?;
+        let offset = Size::from_bytes(offset);
+
+        // Ensure that the access is within bounds.
+        assert!(op_place.layout.size >= offset + layout.size);
+        let value_place = op_place.offset(offset, layout, this)?;
+        Ok(value_place)
+    }
+
+    fn read_scalar_at_offset(
+        &self,
+        op: &OpTy<'tcx, Provenance>,
+        offset: u64,
+        layout: TyAndLayout<'tcx>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+        let value_place = this.deref_operand_and_offset(op, offset, layout)?;
+        this.read_scalar(&value_place.into())
+    }
+
+    fn write_immediate_at_offset(
+        &mut self,
+        op: &OpTy<'tcx, Provenance>,
+        offset: u64,
+        value: &ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, ()> {
+        let this = self.eval_context_mut();
+        let value_place = this.deref_operand_and_offset(op, offset, value.layout)?;
+        this.write_immediate(**value, &value_place.into())
+    }
+
+    fn write_scalar_at_offset(
+        &mut self,
+        op: &OpTy<'tcx, Provenance>,
+        offset: u64,
+        value: impl Into<Scalar<Provenance>>,
+        layout: TyAndLayout<'tcx>,
+    ) -> InterpResult<'tcx, ()> {
+        self.write_immediate_at_offset(op, offset, &ImmTy::from_scalar(value.into(), layout))
+    }
+
+    /// Parse a `timespec` struct and return it as a `std::time::Duration`. It returns `None`
+    /// if the value in the `timespec` struct is invalid. Some libc functions will return
+    /// `EINVAL` in this case.
+    fn read_timespec(
+        &mut self,
+        tp: &MPlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Option<Duration>> {
+        let this = self.eval_context_mut();
+        let seconds_place = this.mplace_field(tp, 0)?;
+        let seconds_scalar = this.read_scalar(&seconds_place.into())?;
+        let seconds = seconds_scalar.to_machine_isize(this)?;
+        let nanoseconds_place = this.mplace_field(tp, 1)?;
+        let nanoseconds_scalar = this.read_scalar(&nanoseconds_place.into())?;
+        let nanoseconds = nanoseconds_scalar.to_machine_isize(this)?;
+
+        Ok(try {
+            // tv_sec must be non-negative.
+            let seconds: u64 = seconds.try_into().ok()?;
+            // tv_nsec must be non-negative.
+            let nanoseconds: u32 = nanoseconds.try_into().ok()?;
+            if nanoseconds >= 1_000_000_000 {
+                // tv_nsec must not be greater than 999,999,999.
+                None?
+            }
+            Duration::new(seconds, nanoseconds)
+        })
+    }
+
+    fn read_c_str<'a>(&'a self, ptr: Pointer<Option<Provenance>>) -> InterpResult<'tcx, &'a [u8]>
+    where
+        'tcx: 'a,
+        'mir: 'a,
+    {
+        let this = self.eval_context_ref();
+        let size1 = Size::from_bytes(1);
+
+        // Step 1: determine the length.
+        let mut len = Size::ZERO;
+        loop {
+            // FIXME: We are re-getting the allocation each time around the loop.
+            // Would be nice if we could somehow "extend" an existing AllocRange.
+            let alloc = this.get_ptr_alloc(ptr.offset(len, this)?, size1, Align::ONE)?.unwrap(); // not a ZST, so we will get a result
+            let byte = alloc.read_integer(alloc_range(Size::ZERO, size1))?.to_u8()?;
+            if byte == 0 {
+                break;
+            } else {
+                len += size1;
+            }
+        }
+
+        // Step 2: get the bytes.
+        this.read_bytes_ptr_strip_provenance(ptr, len)
+    }
+
+    fn read_wide_str(&self, mut ptr: Pointer<Option<Provenance>>) -> InterpResult<'tcx, Vec<u16>> {
+        let this = self.eval_context_ref();
+        let size2 = Size::from_bytes(2);
+        let align2 = Align::from_bytes(2).unwrap();
+
+        let mut wchars = Vec::new();
+        loop {
+            // FIXME: We are re-getting the allocation each time around the loop.
+            // Would be nice if we could somehow "extend" an existing AllocRange.
+            let alloc = this.get_ptr_alloc(ptr, size2, align2)?.unwrap(); // not a ZST, so we will get a result
+            let wchar = alloc.read_integer(alloc_range(Size::ZERO, size2))?.to_u16()?;
+            if wchar == 0 {
+                break;
+            } else {
+                wchars.push(wchar);
+                ptr = ptr.offset(size2, this)?;
+            }
+        }
+
+        Ok(wchars)
+    }
+
+    /// Check that the ABI is what we expect.
+    fn check_abi<'a>(&self, abi: Abi, exp_abi: Abi) -> InterpResult<'a, ()> {
+        if self.eval_context_ref().machine.enforce_abi && abi != exp_abi {
+            throw_ub_format!(
+                "calling a function with ABI {} using caller ABI {}",
+                exp_abi.name(),
+                abi.name()
+            )
+        }
+        Ok(())
+    }
+
+    fn frame_in_std(&self) -> bool {
+        let this = self.eval_context_ref();
+        let Some(start_fn) = this.tcx.lang_items().start_fn() else {
+            // no_std situations
+            return false;
+        };
+        let frame = this.frame();
+        // Make an attempt to get at the instance of the function this is inlined from.
+        let instance: Option<_> = try {
+            let scope = frame.current_source_info()?.scope;
+            let inlined_parent = frame.body.source_scopes[scope].inlined_parent_scope?;
+            let source = &frame.body.source_scopes[inlined_parent];
+            source.inlined.expect("inlined_parent_scope points to scope without inline info").0
+        };
+        // Fall back to the instance of the function itself.
+        let instance = instance.unwrap_or(frame.instance);
+        // Now check if this is in the same crate as start_fn.
+        // As a special exception we also allow unit tests from
+        // <https://github.com/rust-lang/miri-test-libstd/tree/master/std_miri_test> to call these
+        // shims.
+        let frame_crate = this.tcx.def_path(instance.def_id()).krate;
+        frame_crate == this.tcx.def_path(start_fn).krate
+            || this.tcx.crate_name(frame_crate).as_str() == "std_miri_test"
+    }
+
+    /// Handler that should be called when unsupported functionality is encountered.
+    /// This function will either panic within the context of the emulated application
+    /// or return an error in the Miri process context
+    ///
+    /// Return value of `Ok(bool)` indicates whether execution should continue.
+    fn handle_unsupported<S: AsRef<str>>(&mut self, error_msg: S) -> InterpResult<'tcx, ()> {
+        let this = self.eval_context_mut();
+        if this.machine.panic_on_unsupported {
+            // message is slightly different here to make automated analysis easier
+            let error_msg = format!("unsupported Miri functionality: {}", error_msg.as_ref());
+            this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?;
+            Ok(())
+        } else {
+            throw_unsup_format!("{}", error_msg.as_ref());
+        }
+    }
+
+    fn check_abi_and_shim_symbol_clash(
+        &mut self,
+        abi: Abi,
+        exp_abi: Abi,
+        link_name: Symbol,
+    ) -> InterpResult<'tcx, ()> {
+        self.check_abi(abi, exp_abi)?;
+        if let Some((body, _)) = self.eval_context_mut().lookup_exported_symbol(link_name)? {
+            throw_machine_stop!(TerminationInfo::SymbolShimClashing {
+                link_name,
+                span: body.span.data(),
+            })
+        }
+        Ok(())
+    }
+
+    fn check_shim<'a, const N: usize>(
+        &mut self,
+        abi: Abi,
+        exp_abi: Abi,
+        link_name: Symbol,
+        args: &'a [OpTy<'tcx, Provenance>],
+    ) -> InterpResult<'tcx, &'a [OpTy<'tcx, Provenance>; N]>
+    where
+        &'a [OpTy<'tcx, Provenance>; N]: TryFrom<&'a [OpTy<'tcx, Provenance>]>,
+    {
+        self.check_abi_and_shim_symbol_clash(abi, exp_abi, link_name)?;
+        check_arg_count(args)
+    }
+
+    /// Mark a machine allocation that was just created as immutable.
+    fn mark_immutable(&mut self, mplace: &MemPlace<Provenance>) {
+        let this = self.eval_context_mut();
+        // This got just allocated, so there definitely is a pointer here.
+        let provenance = mplace.ptr.into_pointer_or_addr().unwrap().provenance;
+        this.alloc_mark_immutable(provenance.get_alloc_id().unwrap()).unwrap();
+    }
+
+    fn item_link_name(&self, def_id: DefId) -> Symbol {
+        let tcx = self.eval_context_ref().tcx;
+        match tcx.get_attrs(def_id, sym::link_name).filter_map(|a| a.value_str()).next() {
+            Some(name) => name,
+            None => tcx.item_name(def_id),
+        }
+    }
+}
+
+impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
+    pub fn current_span(&self) -> CurrentSpan<'_, 'mir, 'tcx> {
+        CurrentSpan { current_frame_idx: None, machine: self }
+    }
+}
+
+/// A `CurrentSpan` should be created infrequently (ideally once) per interpreter step. It does
+/// nothing on creation, but when `CurrentSpan::get` is called, searches the current stack for the
+/// topmost frame which corresponds to a local crate, and returns the current span in that frame.
+/// The result of that search is cached so that later calls are approximately free.
+#[derive(Clone)]
+pub struct CurrentSpan<'a, 'mir, 'tcx> {
+    current_frame_idx: Option<usize>,
+    machine: &'a MiriMachine<'mir, 'tcx>,
+}
+
+impl<'a, 'mir: 'a, 'tcx: 'a + 'mir> CurrentSpan<'a, 'mir, 'tcx> {
+    pub fn machine(&self) -> &'a MiriMachine<'mir, 'tcx> {
+        self.machine
+    }
+
+    /// Get the current span, skipping non-local frames.
+    /// This function is backed by a cache, and can be assumed to be very fast.
+    pub fn get(&mut self) -> Span {
+        let idx = self.current_frame_idx();
+        Self::frame_span(self.machine, idx)
+    }
+
+    /// Similar to `CurrentSpan::get`, but retrieves the parent frame of the first non-local frame.
+    /// This is useful when we are processing something which occurs on function-entry and we want
+    /// to point at the call to the function, not the function definition generally.
+    pub fn get_parent(&mut self) -> Span {
+        let idx = self.current_frame_idx();
+        Self::frame_span(self.machine, idx.wrapping_sub(1))
+    }
+
+    fn frame_span(machine: &MiriMachine<'_, '_>, idx: usize) -> Span {
+        machine
+            .threads
+            .active_thread_stack()
+            .get(idx)
+            .map(Frame::current_span)
+            .unwrap_or(rustc_span::DUMMY_SP)
+    }
+
+    fn current_frame_idx(&mut self) -> usize {
+        *self
+            .current_frame_idx
+            .get_or_insert_with(|| Self::compute_current_frame_index(self.machine))
+    }
+
+    // Find the position of the inner-most frame which is part of the crate being
+    // compiled/executed, part of the Cargo workspace, and is also not #[track_caller].
+    #[inline(never)]
+    fn compute_current_frame_index(machine: &MiriMachine<'_, '_>) -> usize {
+        machine
+            .threads
+            .active_thread_stack()
+            .iter()
+            .enumerate()
+            .rev()
+            .find_map(|(idx, frame)| {
+                let def_id = frame.instance.def_id();
+                if (def_id.is_local() || machine.local_crates.contains(&def_id.krate))
+                    && !frame.instance.def.requires_caller_location(machine.tcx)
+                {
+                    Some(idx)
+                } else {
+                    None
+                }
+            })
+            .unwrap_or(0)
+    }
+}
+
+/// Check that the number of args is what we expect.
+pub fn check_arg_count<'a, 'tcx, const N: usize>(
+    args: &'a [OpTy<'tcx, Provenance>],
+) -> InterpResult<'tcx, &'a [OpTy<'tcx, Provenance>; N]>
+where
+    &'a [OpTy<'tcx, Provenance>; N]: TryFrom<&'a [OpTy<'tcx, Provenance>]>,
+{
+    if let Ok(ops) = args.try_into() {
+        return Ok(ops);
+    }
+    throw_ub_format!("incorrect number of arguments: got {}, expected {}", args.len(), N)
+}
+
+pub fn isolation_abort_error<'tcx>(name: &str) -> InterpResult<'tcx> {
+    throw_machine_stop!(TerminationInfo::UnsupportedInIsolation(format!(
+        "{} not available when isolation is enabled",
+        name,
+    )))
+}
+
+/// Retrieve the list of local crates that should have been passed by cargo-miri in
+/// MIRI_LOCAL_CRATES and turn them into `CrateNum`s.
+pub fn get_local_crates(tcx: TyCtxt<'_>) -> Vec<CrateNum> {
+    // Convert the local crate names from the passed-in config into CrateNums so that they can
+    // be looked up quickly during execution
+    let local_crate_names = std::env::var("MIRI_LOCAL_CRATES")
+        .map(|crates| crates.split(',').map(|krate| krate.to_string()).collect::<Vec<_>>())
+        .unwrap_or_default();
+    let mut local_crates = Vec::new();
+    for &crate_num in tcx.crates(()) {
+        let name = tcx.crate_name(crate_num);
+        let name = name.as_str();
+        if local_crate_names.iter().any(|local_name| local_name == name) {
+            local_crates.push(crate_num);
+        }
+    }
+    local_crates
+}
+
+/// Helper function used inside the shims of foreign functions to check that
+/// `target_os` is a supported UNIX OS.
+pub fn target_os_is_unix(target_os: &str) -> bool {
+    matches!(target_os, "linux" | "macos" | "freebsd" | "android")
+}
diff --git a/src/tools/miri/src/helpers/convert.rs b/src/tools/miri/src/helpers/convert.rs
new file mode 100644
index 000000000000..4506fe47495d
--- /dev/null
+++ b/src/tools/miri/src/helpers/convert.rs
@@ -0,0 +1,49 @@
+use implementations::NarrowerThan;
+
+/// Replacement for `as` casts going from wide integer to narrower integer.
+///
+/// # Example
+///
+/// ```ignore
+/// let x = 99_u64;
+/// let lo = x.truncate::<u16>();
+/// // lo is of type u16, equivalent to `x as u16`.
+/// ```
+pub(crate) trait Truncate: Sized {
+    fn truncate<To>(self) -> To
+    where
+        To: NarrowerThan<Self>,
+    {
+        NarrowerThan::truncate_from(self)
+    }
+}
+
+impl Truncate for u16 {}
+impl Truncate for u32 {}
+impl Truncate for u64 {}
+impl Truncate for u128 {}
+
+mod implementations {
+    pub(crate) trait NarrowerThan<T> {
+        fn truncate_from(wide: T) -> Self;
+    }
+
+    macro_rules! impl_narrower_than {
+        ($(NarrowerThan<{$($ty:ty),*}> for $self:ty)*) => {
+            $($(
+                impl NarrowerThan<$ty> for $self {
+                    fn truncate_from(wide: $ty) -> Self {
+                        wide as Self
+                    }
+                }
+            )*)*
+        };
+    }
+
+    impl_narrower_than! {
+        NarrowerThan<{u128, u64, u32, u16}> for u8
+        NarrowerThan<{u128, u64, u32}> for u16
+        NarrowerThan<{u128, u64}> for u32
+        NarrowerThan<{u128}> for u64
+    }
+}
diff --git a/src/tools/miri/src/intptrcast.rs b/src/tools/miri/src/intptrcast.rs
new file mode 100644
index 000000000000..b9e5def8fa7c
--- /dev/null
+++ b/src/tools/miri/src/intptrcast.rs
@@ -0,0 +1,260 @@
+use std::cell::RefCell;
+use std::cmp::max;
+use std::collections::hash_map::Entry;
+
+use log::trace;
+use rand::Rng;
+
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_span::Span;
+use rustc_target::abi::{HasDataLayout, Size};
+
+use crate::*;
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum ProvenanceMode {
+    /// We support `expose_addr`/`from_exposed_addr` via "wildcard" provenance.
+    /// However, we want on `from_exposed_addr` to alert the user of the precision loss.
+    Default,
+    /// Like `Default`, but without the warning.
+    Permissive,
+    /// We error on `from_exposed_addr`, ensuring no precision loss.
+    Strict,
+}
+
+pub type GlobalState = RefCell<GlobalStateInner>;
+
+#[derive(Clone, Debug)]
+pub struct GlobalStateInner {
+    /// This is used as a map between the address of each allocation and its `AllocId`.
+    /// It is always sorted
+    int_to_ptr_map: Vec<(u64, AllocId)>,
+    /// The base address for each allocation.  We cannot put that into
+    /// `AllocExtra` because function pointers also have a base address, and
+    /// they do not have an `AllocExtra`.
+    /// This is the inverse of `int_to_ptr_map`.
+    base_addr: FxHashMap<AllocId, u64>,
+    /// Whether an allocation has been exposed or not. This cannot be put
+    /// into `AllocExtra` for the same reason as `base_addr`.
+    exposed: FxHashSet<AllocId>,
+    /// This is used as a memory address when a new pointer is casted to an integer. It
+    /// is always larger than any address that was previously made part of a block.
+    next_base_addr: u64,
+    /// The provenance to use for int2ptr casts
+    provenance_mode: ProvenanceMode,
+}
+
+impl GlobalStateInner {
+    pub fn new(config: &MiriConfig) -> Self {
+        GlobalStateInner {
+            int_to_ptr_map: Vec::default(),
+            base_addr: FxHashMap::default(),
+            exposed: FxHashSet::default(),
+            next_base_addr: STACK_ADDR,
+            provenance_mode: config.provenance_mode,
+        }
+    }
+}
+
+impl<'mir, 'tcx> GlobalStateInner {
+    // Returns the exposed `AllocId` that corresponds to the specified addr,
+    // or `None` if the addr is out of bounds
+    fn alloc_id_from_addr(ecx: &MiriInterpCx<'mir, 'tcx>, addr: u64) -> Option<AllocId> {
+        let global_state = ecx.machine.intptrcast.borrow();
+        assert!(global_state.provenance_mode != ProvenanceMode::Strict);
+
+        let pos = global_state.int_to_ptr_map.binary_search_by_key(&addr, |(addr, _)| *addr);
+
+        // Determine the in-bounds provenance for this pointer.
+        // (This is only called on an actual access, so in-bounds is the only possible kind of provenance.)
+        let alloc_id = match pos {
+            Ok(pos) => Some(global_state.int_to_ptr_map[pos].1),
+            Err(0) => None,
+            Err(pos) => {
+                // This is the largest of the adresses smaller than `int`,
+                // i.e. the greatest lower bound (glb)
+                let (glb, alloc_id) = global_state.int_to_ptr_map[pos - 1];
+                // This never overflows because `addr >= glb`
+                let offset = addr - glb;
+                // If the offset exceeds the size of the allocation, don't use this `alloc_id`.
+                let size = ecx.get_alloc_info(alloc_id).0;
+                if offset <= size.bytes() { Some(alloc_id) } else { None }
+            }
+        }?;
+
+        // We only use this provenance if it has been exposed, *and* is still live.
+        if global_state.exposed.contains(&alloc_id) {
+            let (_size, _align, kind) = ecx.get_alloc_info(alloc_id);
+            match kind {
+                AllocKind::LiveData | AllocKind::Function | AllocKind::VTable => {
+                    return Some(alloc_id);
+                }
+                AllocKind::Dead => {}
+            }
+        }
+
+        None
+    }
+
+    pub fn expose_ptr(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        alloc_id: AllocId,
+        sb: SbTag,
+    ) -> InterpResult<'tcx> {
+        let global_state = ecx.machine.intptrcast.get_mut();
+        // In strict mode, we don't need this, so we can save some cycles by not tracking it.
+        if global_state.provenance_mode != ProvenanceMode::Strict {
+            trace!("Exposing allocation id {alloc_id:?}");
+            global_state.exposed.insert(alloc_id);
+            if ecx.machine.stacked_borrows.is_some() {
+                ecx.expose_tag(alloc_id, sb)?;
+            }
+        }
+        Ok(())
+    }
+
+    pub fn ptr_from_addr_transmute(
+        _ecx: &MiriInterpCx<'mir, 'tcx>,
+        addr: u64,
+    ) -> Pointer<Option<Provenance>> {
+        trace!("Transmuting {:#x} to a pointer", addr);
+
+        // We consider transmuted pointers to be "invalid" (`None` provenance).
+        Pointer::new(None, Size::from_bytes(addr))
+    }
+
+    pub fn ptr_from_addr_cast(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        addr: u64,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        trace!("Casting {:#x} to a pointer", addr);
+
+        let global_state = ecx.machine.intptrcast.borrow();
+
+        match global_state.provenance_mode {
+            ProvenanceMode::Default => {
+                // The first time this happens at a particular location, print a warning.
+                thread_local! {
+                    // `Span` is non-`Send`, so we use a thread-local instead.
+                    static PAST_WARNINGS: RefCell<FxHashSet<Span>> = RefCell::default();
+                }
+                PAST_WARNINGS.with_borrow_mut(|past_warnings| {
+                    let first = past_warnings.is_empty();
+                    if past_warnings.insert(ecx.cur_span()) {
+                        // Newly inserted, so first time we see this span.
+                        ecx.emit_diagnostic(NonHaltingDiagnostic::Int2Ptr { details: first });
+                    }
+                });
+            }
+            ProvenanceMode::Strict => {
+                throw_machine_stop!(TerminationInfo::Int2PtrWithStrictProvenance);
+            }
+            ProvenanceMode::Permissive => {}
+        }
+
+        // This is how wildcard pointers are born.
+        Ok(Pointer::new(Some(Provenance::Wildcard), Size::from_bytes(addr)))
+    }
+
+    fn alloc_base_addr(ecx: &MiriInterpCx<'mir, 'tcx>, alloc_id: AllocId) -> u64 {
+        let mut global_state = ecx.machine.intptrcast.borrow_mut();
+        let global_state = &mut *global_state;
+
+        match global_state.base_addr.entry(alloc_id) {
+            Entry::Occupied(entry) => *entry.get(),
+            Entry::Vacant(entry) => {
+                // There is nothing wrong with a raw pointer being cast to an integer only after
+                // it became dangling.  Hence we allow dead allocations.
+                let (size, align, _kind) = ecx.get_alloc_info(alloc_id);
+
+                // This allocation does not have a base address yet, pick one.
+                // Leave some space to the previous allocation, to give it some chance to be less aligned.
+                let slack = {
+                    let mut rng = ecx.machine.rng.borrow_mut();
+                    // This means that `(global_state.next_base_addr + slack) % 16` is uniformly distributed.
+                    rng.gen_range(0..16)
+                };
+                // From next_base_addr + slack, round up to adjust for alignment.
+                let base_addr = global_state.next_base_addr.checked_add(slack).unwrap();
+                let base_addr = Self::align_addr(base_addr, align.bytes());
+                entry.insert(base_addr);
+                trace!(
+                    "Assigning base address {:#x} to allocation {:?} (size: {}, align: {}, slack: {})",
+                    base_addr,
+                    alloc_id,
+                    size.bytes(),
+                    align.bytes(),
+                    slack,
+                );
+
+                // Remember next base address.  If this allocation is zero-sized, leave a gap
+                // of at least 1 to avoid two allocations having the same base address.
+                // (The logic in `alloc_id_from_addr` assumes unique addresses, and different
+                // function/vtable pointers need to be distinguishable!)
+                global_state.next_base_addr = base_addr.checked_add(max(size.bytes(), 1)).unwrap();
+                // Given that `next_base_addr` increases in each allocation, pushing the
+                // corresponding tuple keeps `int_to_ptr_map` sorted
+                global_state.int_to_ptr_map.push((base_addr, alloc_id));
+
+                base_addr
+            }
+        }
+    }
+
+    /// Convert a relative (tcx) pointer to an absolute address.
+    pub fn rel_ptr_to_addr(ecx: &MiriInterpCx<'mir, 'tcx>, ptr: Pointer<AllocId>) -> u64 {
+        let (alloc_id, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
+        let base_addr = GlobalStateInner::alloc_base_addr(ecx, alloc_id);
+
+        // Add offset with the right kind of pointer-overflowing arithmetic.
+        let dl = ecx.data_layout();
+        dl.overflowing_offset(base_addr, offset.bytes()).0
+    }
+
+    /// When a pointer is used for a memory access, this computes where in which allocation the
+    /// access is going.
+    pub fn abs_ptr_to_rel(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        ptr: Pointer<Provenance>,
+    ) -> Option<(AllocId, Size)> {
+        let (tag, addr) = ptr.into_parts(); // addr is absolute (Tag provenance)
+
+        let alloc_id = if let Provenance::Concrete { alloc_id, .. } = tag {
+            alloc_id
+        } else {
+            // A wildcard pointer.
+            GlobalStateInner::alloc_id_from_addr(ecx, addr.bytes())?
+        };
+
+        let base_addr = GlobalStateInner::alloc_base_addr(ecx, alloc_id);
+
+        // Wrapping "addr - base_addr"
+        let dl = ecx.data_layout();
+        #[allow(clippy::cast_possible_wrap)] // we want to wrap here
+        let neg_base_addr = (base_addr as i64).wrapping_neg();
+        Some((
+            alloc_id,
+            Size::from_bytes(dl.overflowing_signed_offset(addr.bytes(), neg_base_addr).0),
+        ))
+    }
+
+    /// Shifts `addr` to make it aligned with `align` by rounding `addr` to the smallest multiple
+    /// of `align` that is larger or equal to `addr`
+    fn align_addr(addr: u64, align: u64) -> u64 {
+        match addr % align {
+            0 => addr,
+            rem => addr.checked_add(align).unwrap() - rem,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_align_addr() {
+        assert_eq!(GlobalStateInner::align_addr(37, 4), 40);
+        assert_eq!(GlobalStateInner::align_addr(44, 4), 44);
+    }
+}
diff --git a/src/tools/miri/src/lib.rs b/src/tools/miri/src/lib.rs
new file mode 100644
index 000000000000..cda27beab300
--- /dev/null
+++ b/src/tools/miri/src/lib.rs
@@ -0,0 +1,127 @@
+#![feature(rustc_private)]
+#![feature(map_first_last)]
+#![feature(map_try_insert)]
+#![feature(never_type)]
+#![feature(try_blocks)]
+#![feature(io_error_more)]
+#![feature(int_log)]
+#![feature(variant_count)]
+#![feature(yeet_expr)]
+#![feature(is_some_with)]
+#![feature(nonzero_ops)]
+#![feature(local_key_cell_methods)]
+#![cfg_attr(bootstrap, feature(let_else))]
+// Configure clippy and other lints
+#![allow(
+    clippy::collapsible_else_if,
+    clippy::collapsible_if,
+    clippy::comparison_chain,
+    clippy::enum_variant_names,
+    clippy::field_reassign_with_default,
+    clippy::manual_map,
+    clippy::new_without_default,
+    clippy::single_match,
+    clippy::useless_format,
+    clippy::derive_partial_eq_without_eq,
+    clippy::derive_hash_xor_eq,
+    clippy::too_many_arguments,
+    clippy::type_complexity,
+    clippy::single_element_loop,
+    clippy::needless_return,
+    // We are not implementing queries here so it's fine
+    rustc::potential_query_instability
+)]
+#![warn(
+    rust_2018_idioms,
+    clippy::cast_possible_wrap, // unsigned -> signed
+    clippy::cast_sign_loss, // signed -> unsigned
+    clippy::cast_lossless,
+    clippy::cast_possible_truncation,
+)]
+
+extern crate rustc_apfloat;
+extern crate rustc_ast;
+#[macro_use]
+extern crate rustc_middle;
+extern crate rustc_const_eval;
+extern crate rustc_data_structures;
+extern crate rustc_hir;
+extern crate rustc_index;
+extern crate rustc_session;
+extern crate rustc_span;
+extern crate rustc_target;
+
+mod clock;
+mod concurrency;
+mod diagnostics;
+mod eval;
+mod helpers;
+mod intptrcast;
+mod machine;
+mod mono_hash_map;
+mod operator;
+mod range_map;
+mod shims;
+mod stacked_borrows;
+mod tag_gc;
+
+// Establish a "crate-wide prelude": we often import `crate::*`.
+
+// Make all those symbols available in the same place as our own.
+pub use rustc_const_eval::interpret::*;
+// Resolve ambiguity.
+pub use rustc_const_eval::interpret::{self, AllocMap, PlaceTy, Provenance as _};
+
+pub use crate::shims::dlsym::{Dlsym, EvalContextExt as _};
+pub use crate::shims::env::{EnvVars, EvalContextExt as _};
+pub use crate::shims::foreign_items::EvalContextExt as _;
+pub use crate::shims::intrinsics::EvalContextExt as _;
+pub use crate::shims::os_str::EvalContextExt as _;
+pub use crate::shims::panic::{CatchUnwindData, EvalContextExt as _};
+pub use crate::shims::time::EvalContextExt as _;
+pub use crate::shims::tls::{EvalContextExt as _, TlsData};
+pub use crate::shims::EvalContextExt as _;
+
+pub use crate::clock::{Clock, Instant};
+pub use crate::concurrency::{
+    data_race::{
+        AtomicFenceOrd, AtomicReadOrd, AtomicRwOrd, AtomicWriteOrd,
+        EvalContextExt as DataRaceEvalContextExt,
+    },
+    sync::{CondvarId, EvalContextExt as SyncEvalContextExt, MutexId, RwLockId},
+    thread::{
+        EvalContextExt as ThreadsEvalContextExt, SchedulingAction, ThreadId, ThreadManager,
+        ThreadState, Time,
+    },
+};
+pub use crate::diagnostics::{
+    report_error, EvalContextExt as DiagnosticsEvalContextExt, NonHaltingDiagnostic,
+    TerminationInfo,
+};
+pub use crate::eval::{
+    create_ecx, eval_entry, AlignmentCheck, BacktraceStyle, IsolatedOp, MiriConfig, RejectOpWith,
+};
+pub use crate::helpers::{CurrentSpan, EvalContextExt as HelpersEvalContextExt};
+pub use crate::intptrcast::ProvenanceMode;
+pub use crate::machine::{
+    AllocExtra, FrameData, MiriInterpCx, MiriInterpCxExt, MiriMachine, MiriMemoryKind, Provenance,
+    ProvenanceExtra, NUM_CPUS, PAGE_SIZE, STACK_ADDR, STACK_SIZE,
+};
+pub use crate::mono_hash_map::MonoHashMap;
+pub use crate::operator::EvalContextExt as OperatorEvalContextExt;
+pub use crate::range_map::RangeMap;
+pub use crate::stacked_borrows::{
+    CallId, EvalContextExt as StackedBorEvalContextExt, Item, Permission, SbTag, Stack, Stacks,
+};
+pub use crate::tag_gc::EvalContextExt as _;
+
+/// Insert rustc arguments at the beginning of the argument list that Miri wants to be
+/// set per default, for maximal validation power.
+pub const MIRI_DEFAULT_ARGS: &[&str] = &[
+    "-Zalways-encode-mir",
+    "-Zmir-emit-retag",
+    "-Zmir-opt-level=0",
+    "--cfg=miri",
+    "-Cdebug-assertions=on",
+    "-Zextra-const-ub-checks",
+];
diff --git a/src/tools/miri/src/machine.rs b/src/tools/miri/src/machine.rs
new file mode 100644
index 000000000000..dcfb998c5645
--- /dev/null
+++ b/src/tools/miri/src/machine.rs
@@ -0,0 +1,1077 @@
+//! Global machine state as well as implementation of the interpreter engine
+//! `Machine` trait.
+
+use std::borrow::Cow;
+use std::cell::RefCell;
+use std::fmt;
+
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+
+use rustc_ast::ast::Mutability;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+#[allow(unused)]
+use rustc_data_structures::static_assert_size;
+use rustc_middle::{
+    mir,
+    ty::{
+        self,
+        layout::{LayoutCx, LayoutError, LayoutOf, TyAndLayout},
+        Instance, Ty, TyCtxt, TypeAndMut,
+    },
+};
+use rustc_span::def_id::{CrateNum, DefId};
+use rustc_span::Symbol;
+use rustc_target::abi::Size;
+use rustc_target::spec::abi::Abi;
+
+use crate::{
+    concurrency::{data_race, weak_memory},
+    shims::unix::FileHandler,
+    *,
+};
+
+// Some global facts about the emulated machine.
+pub const PAGE_SIZE: u64 = 4 * 1024; // FIXME: adjust to target architecture
+pub const STACK_ADDR: u64 = 32 * PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
+pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
+pub const NUM_CPUS: u64 = 1;
+
+/// Extra data stored with each stack frame
+pub struct FrameData<'tcx> {
+    /// Extra data for Stacked Borrows.
+    pub stacked_borrows: Option<stacked_borrows::FrameExtra>,
+
+    /// If this is Some(), then this is a special "catch unwind" frame (the frame of `try_fn`
+    /// called by `try`). When this frame is popped during unwinding a panic,
+    /// we stop unwinding, use the `CatchUnwindData` to handle catching.
+    pub catch_unwind: Option<CatchUnwindData<'tcx>>,
+
+    /// If `measureme` profiling is enabled, holds timing information
+    /// for the start of this frame. When we finish executing this frame,
+    /// we use this to register a completed event with `measureme`.
+    pub timing: Option<measureme::DetachedTiming>,
+}
+
+impl<'tcx> std::fmt::Debug for FrameData<'tcx> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        // Omitting `timing`, it does not support `Debug`.
+        let FrameData { stacked_borrows, catch_unwind, timing: _ } = self;
+        f.debug_struct("FrameData")
+            .field("stacked_borrows", stacked_borrows)
+            .field("catch_unwind", catch_unwind)
+            .finish()
+    }
+}
+
+/// Extra memory kinds
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum MiriMemoryKind {
+    /// `__rust_alloc` memory.
+    Rust,
+    /// `malloc` memory.
+    C,
+    /// Windows `HeapAlloc` memory.
+    WinHeap,
+    /// Memory for args, errno, and other parts of the machine-managed environment.
+    /// This memory may leak.
+    Machine,
+    /// Memory allocated by the runtime (e.g. env vars). Separate from `Machine`
+    /// because we clean it up and leak-check it.
+    Runtime,
+    /// Globals copied from `tcx`.
+    /// This memory may leak.
+    Global,
+    /// Memory for extern statics.
+    /// This memory may leak.
+    ExternStatic,
+    /// Memory for thread-local statics.
+    /// This memory may leak.
+    Tls,
+}
+
+impl From<MiriMemoryKind> for MemoryKind<MiriMemoryKind> {
+    #[inline(always)]
+    fn from(kind: MiriMemoryKind) -> MemoryKind<MiriMemoryKind> {
+        MemoryKind::Machine(kind)
+    }
+}
+
+impl MayLeak for MiriMemoryKind {
+    #[inline(always)]
+    fn may_leak(self) -> bool {
+        use self::MiriMemoryKind::*;
+        match self {
+            Rust | C | WinHeap | Runtime => false,
+            Machine | Global | ExternStatic | Tls => true,
+        }
+    }
+}
+
+impl fmt::Display for MiriMemoryKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        use self::MiriMemoryKind::*;
+        match self {
+            Rust => write!(f, "Rust heap"),
+            C => write!(f, "C heap"),
+            WinHeap => write!(f, "Windows heap"),
+            Machine => write!(f, "machine-managed memory"),
+            Runtime => write!(f, "language runtime memory"),
+            Global => write!(f, "global (static or const)"),
+            ExternStatic => write!(f, "extern static"),
+            Tls => write!(f, "thread-local static"),
+        }
+    }
+}
+
+/// Pointer provenance.
+#[derive(Debug, Clone, Copy)]
+pub enum Provenance {
+    Concrete {
+        alloc_id: AllocId,
+        /// Stacked Borrows tag.
+        sb: SbTag,
+    },
+    Wildcard,
+}
+
+// This needs to be `Eq`+`Hash` because the `Machine` trait needs that because validity checking
+// *might* be recursive and then it has to track which places have already been visited.
+// However, comparing provenance is meaningless, since `Wildcard` might be any provenance -- and of
+// course we don't actually do recursive checking.
+// We could change `RefTracking` to strip provenance for its `seen` set but that type is generic so that is quite annoying.
+// Instead owe add the required instances but make them panic.
+impl PartialEq for Provenance {
+    fn eq(&self, _other: &Self) -> bool {
+        panic!("Provenance must not be compared")
+    }
+}
+impl Eq for Provenance {}
+impl std::hash::Hash for Provenance {
+    fn hash<H: std::hash::Hasher>(&self, _state: &mut H) {
+        panic!("Provenance must not be hashed")
+    }
+}
+
+/// The "extra" information a pointer has over a regular AllocId.
+#[derive(Copy, Clone, PartialEq)]
+pub enum ProvenanceExtra {
+    Concrete(SbTag),
+    Wildcard,
+}
+
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+static_assert_size!(Pointer<Provenance>, 24);
+// FIXME: this would with in 24bytes but layout optimizations are not smart enough
+// #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+//static_assert_size!(Pointer<Option<Provenance>>, 24);
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+static_assert_size!(Scalar<Provenance>, 32);
+
+impl interpret::Provenance for Provenance {
+    /// We use absolute addresses in the `offset` of a `Pointer<Provenance>`.
+    const OFFSET_IS_ADDR: bool = true;
+
+    /// We cannot err on partial overwrites, it happens too often in practice (due to unions).
+    const ERR_ON_PARTIAL_PTR_OVERWRITE: bool = false;
+
+    fn fmt(ptr: &Pointer<Self>, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let (prov, addr) = ptr.into_parts(); // address is absolute
+        write!(f, "{:#x}", addr.bytes())?;
+
+        match prov {
+            Provenance::Concrete { alloc_id, sb } => {
+                // Forward `alternate` flag to `alloc_id` printing.
+                if f.alternate() {
+                    write!(f, "[{:#?}]", alloc_id)?;
+                } else {
+                    write!(f, "[{:?}]", alloc_id)?;
+                }
+                // Print Stacked Borrows tag.
+                write!(f, "{:?}", sb)?;
+            }
+            Provenance::Wildcard => {
+                write!(f, "[wildcard]")?;
+            }
+        }
+
+        Ok(())
+    }
+
+    fn get_alloc_id(self) -> Option<AllocId> {
+        match self {
+            Provenance::Concrete { alloc_id, .. } => Some(alloc_id),
+            Provenance::Wildcard => None,
+        }
+    }
+
+    fn join(left: Option<Self>, right: Option<Self>) -> Option<Self> {
+        match (left, right) {
+            // If both are the *same* concrete tag, that is the result.
+            (
+                Some(Provenance::Concrete { alloc_id: left_alloc, sb: left_sb }),
+                Some(Provenance::Concrete { alloc_id: right_alloc, sb: right_sb }),
+            ) if left_alloc == right_alloc && left_sb == right_sb => left,
+            // If one side is a wildcard, the best possible outcome is that it is equal to the other
+            // one, and we use that.
+            (Some(Provenance::Wildcard), o) | (o, Some(Provenance::Wildcard)) => o,
+            // Otherwise, fall back to `None`.
+            _ => None,
+        }
+    }
+}
+
+impl fmt::Debug for ProvenanceExtra {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ProvenanceExtra::Concrete(pid) => write!(f, "{pid:?}"),
+            ProvenanceExtra::Wildcard => write!(f, "<wildcard>"),
+        }
+    }
+}
+
+impl ProvenanceExtra {
+    pub fn and_then<T>(self, f: impl FnOnce(SbTag) -> Option<T>) -> Option<T> {
+        match self {
+            ProvenanceExtra::Concrete(pid) => f(pid),
+            ProvenanceExtra::Wildcard => None,
+        }
+    }
+}
+
+/// Extra per-allocation data
+#[derive(Debug, Clone)]
+pub struct AllocExtra {
+    /// Stacked Borrows state is only added if it is enabled.
+    pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
+    /// Data race detection via the use of a vector-clock,
+    ///  this is only added if it is enabled.
+    pub data_race: Option<data_race::AllocExtra>,
+    /// Weak memory emulation via the use of store buffers,
+    ///  this is only added if it is enabled.
+    pub weak_memory: Option<weak_memory::AllocExtra>,
+}
+
+/// Precomputed layouts of primitive types
+pub struct PrimitiveLayouts<'tcx> {
+    pub unit: TyAndLayout<'tcx>,
+    pub i8: TyAndLayout<'tcx>,
+    pub i16: TyAndLayout<'tcx>,
+    pub i32: TyAndLayout<'tcx>,
+    pub isize: TyAndLayout<'tcx>,
+    pub u8: TyAndLayout<'tcx>,
+    pub u16: TyAndLayout<'tcx>,
+    pub u32: TyAndLayout<'tcx>,
+    pub usize: TyAndLayout<'tcx>,
+    pub bool: TyAndLayout<'tcx>,
+    pub mut_raw_ptr: TyAndLayout<'tcx>,   // *mut ()
+    pub const_raw_ptr: TyAndLayout<'tcx>, // *const ()
+}
+
+impl<'mir, 'tcx: 'mir> PrimitiveLayouts<'tcx> {
+    fn new(layout_cx: LayoutCx<'tcx, TyCtxt<'tcx>>) -> Result<Self, LayoutError<'tcx>> {
+        let tcx = layout_cx.tcx;
+        let mut_raw_ptr = tcx.mk_ptr(TypeAndMut { ty: tcx.types.unit, mutbl: Mutability::Mut });
+        let const_raw_ptr = tcx.mk_ptr(TypeAndMut { ty: tcx.types.unit, mutbl: Mutability::Not });
+        Ok(Self {
+            unit: layout_cx.layout_of(tcx.mk_unit())?,
+            i8: layout_cx.layout_of(tcx.types.i8)?,
+            i16: layout_cx.layout_of(tcx.types.i16)?,
+            i32: layout_cx.layout_of(tcx.types.i32)?,
+            isize: layout_cx.layout_of(tcx.types.isize)?,
+            u8: layout_cx.layout_of(tcx.types.u8)?,
+            u16: layout_cx.layout_of(tcx.types.u16)?,
+            u32: layout_cx.layout_of(tcx.types.u32)?,
+            usize: layout_cx.layout_of(tcx.types.usize)?,
+            bool: layout_cx.layout_of(tcx.types.bool)?,
+            mut_raw_ptr: layout_cx.layout_of(mut_raw_ptr)?,
+            const_raw_ptr: layout_cx.layout_of(const_raw_ptr)?,
+        })
+    }
+}
+
+/// The machine itself.
+pub struct MiriMachine<'mir, 'tcx> {
+    // We carry a copy of the global `TyCtxt` for convenience, so methods taking just `&Evaluator` have `tcx` access.
+    pub tcx: TyCtxt<'tcx>,
+
+    /// Stacked Borrows global data.
+    pub stacked_borrows: Option<stacked_borrows::GlobalState>,
+
+    /// Data race detector global data.
+    pub data_race: Option<data_race::GlobalState>,
+
+    /// Ptr-int-cast module global data.
+    pub intptrcast: intptrcast::GlobalState,
+
+    /// Environment variables set by `setenv`.
+    /// Miri does not expose env vars from the host to the emulated program.
+    pub(crate) env_vars: EnvVars<'tcx>,
+
+    /// Program arguments (`Option` because we can only initialize them after creating the ecx).
+    /// These are *pointers* to argc/argv because macOS.
+    /// We also need the full command line as one string because of Windows.
+    pub(crate) argc: Option<MemPlace<Provenance>>,
+    pub(crate) argv: Option<MemPlace<Provenance>>,
+    pub(crate) cmd_line: Option<MemPlace<Provenance>>,
+
+    /// TLS state.
+    pub(crate) tls: TlsData<'tcx>,
+
+    /// What should Miri do when an op requires communicating with the host,
+    /// such as accessing host env vars, random number generation, and
+    /// file system access.
+    pub(crate) isolated_op: IsolatedOp,
+
+    /// Whether to enforce the validity invariant.
+    pub(crate) validate: bool,
+
+    /// Whether to enforce [ABI](Abi) of function calls.
+    pub(crate) enforce_abi: bool,
+
+    /// The table of file descriptors.
+    pub(crate) file_handler: shims::unix::FileHandler,
+    /// The table of directory descriptors.
+    pub(crate) dir_handler: shims::unix::DirHandler,
+
+    /// This machine's monotone clock.
+    pub(crate) clock: Clock,
+
+    /// The set of threads.
+    pub(crate) threads: ThreadManager<'mir, 'tcx>,
+
+    /// Precomputed `TyLayout`s for primitive data types that are commonly used inside Miri.
+    pub(crate) layouts: PrimitiveLayouts<'tcx>,
+
+    /// Allocations that are considered roots of static memory (that may leak).
+    pub(crate) static_roots: Vec<AllocId>,
+
+    /// The `measureme` profiler used to record timing information about
+    /// the emulated program.
+    profiler: Option<measureme::Profiler>,
+    /// Used with `profiler` to cache the `StringId`s for event names
+    /// uesd with `measureme`.
+    string_cache: FxHashMap<String, measureme::StringId>,
+
+    /// Cache of `Instance` exported under the given `Symbol` name.
+    /// `None` means no `Instance` exported under the given name is found.
+    pub(crate) exported_symbols_cache: FxHashMap<Symbol, Option<Instance<'tcx>>>,
+
+    /// Whether to raise a panic in the context of the evaluated process when unsupported
+    /// functionality is encountered. If `false`, an error is propagated in the Miri application context
+    /// instead (default behavior)
+    pub(crate) panic_on_unsupported: bool,
+
+    /// Equivalent setting as RUST_BACKTRACE on encountering an error.
+    pub(crate) backtrace_style: BacktraceStyle,
+
+    /// Crates which are considered local for the purposes of error reporting.
+    pub(crate) local_crates: Vec<CrateNum>,
+
+    /// Mapping extern static names to their base pointer.
+    extern_statics: FxHashMap<Symbol, Pointer<Provenance>>,
+
+    /// The random number generator used for resolving non-determinism.
+    /// Needs to be queried by ptr_to_int, hence needs interior mutability.
+    pub(crate) rng: RefCell<StdRng>,
+
+    /// The allocation IDs to report when they are being allocated
+    /// (helps for debugging memory leaks and use after free bugs).
+    tracked_alloc_ids: FxHashSet<AllocId>,
+
+    /// Controls whether alignment of memory accesses is being checked.
+    pub(crate) check_alignment: AlignmentCheck,
+
+    /// Failure rate of compare_exchange_weak, between 0.0 and 1.0
+    pub(crate) cmpxchg_weak_failure_rate: f64,
+
+    /// Corresponds to -Zmiri-mute-stdout-stderr and doesn't write the output but acts as if it succeeded.
+    pub(crate) mute_stdout_stderr: bool,
+
+    /// Whether weak memory emulation is enabled
+    pub(crate) weak_memory: bool,
+
+    /// The probability of the active thread being preempted at the end of each basic block.
+    pub(crate) preemption_rate: f64,
+
+    /// If `Some`, we will report the current stack every N basic blocks.
+    pub(crate) report_progress: Option<u32>,
+    // The total number of blocks that have been executed.
+    pub(crate) basic_block_count: u64,
+
+    /// Handle of the optional shared object file for external functions.
+    #[cfg(unix)]
+    pub external_so_lib: Option<(libloading::Library, std::path::PathBuf)>,
+
+    /// Run a garbage collector for SbTags every N basic blocks.
+    pub(crate) gc_interval: u32,
+    /// The number of blocks that passed since the last SbTag GC pass.
+    pub(crate) since_gc: u32,
+}
+
+impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
+    pub(crate) fn new(config: &MiriConfig, layout_cx: LayoutCx<'tcx, TyCtxt<'tcx>>) -> Self {
+        let local_crates = helpers::get_local_crates(layout_cx.tcx);
+        let layouts =
+            PrimitiveLayouts::new(layout_cx).expect("Couldn't get layouts of primitive types");
+        let profiler = config.measureme_out.as_ref().map(|out| {
+            measureme::Profiler::new(out).expect("Couldn't create `measureme` profiler")
+        });
+        let rng = StdRng::seed_from_u64(config.seed.unwrap_or(0));
+        let stacked_borrows = config.stacked_borrows.then(|| {
+            RefCell::new(stacked_borrows::GlobalStateInner::new(
+                config.tracked_pointer_tags.clone(),
+                config.tracked_call_ids.clone(),
+                config.retag_fields,
+            ))
+        });
+        let data_race = config.data_race_detector.then(|| data_race::GlobalState::new(config));
+        MiriMachine {
+            tcx: layout_cx.tcx,
+            stacked_borrows,
+            data_race,
+            intptrcast: RefCell::new(intptrcast::GlobalStateInner::new(config)),
+            // `env_vars` depends on a full interpreter so we cannot properly initialize it yet.
+            env_vars: EnvVars::default(),
+            argc: None,
+            argv: None,
+            cmd_line: None,
+            tls: TlsData::default(),
+            isolated_op: config.isolated_op,
+            validate: config.validate,
+            enforce_abi: config.check_abi,
+            file_handler: FileHandler::new(config.mute_stdout_stderr),
+            dir_handler: Default::default(),
+            layouts,
+            threads: ThreadManager::default(),
+            static_roots: Vec::new(),
+            profiler,
+            string_cache: Default::default(),
+            exported_symbols_cache: FxHashMap::default(),
+            panic_on_unsupported: config.panic_on_unsupported,
+            backtrace_style: config.backtrace_style,
+            local_crates,
+            extern_statics: FxHashMap::default(),
+            rng: RefCell::new(rng),
+            tracked_alloc_ids: config.tracked_alloc_ids.clone(),
+            check_alignment: config.check_alignment,
+            cmpxchg_weak_failure_rate: config.cmpxchg_weak_failure_rate,
+            mute_stdout_stderr: config.mute_stdout_stderr,
+            weak_memory: config.weak_memory_emulation,
+            preemption_rate: config.preemption_rate,
+            report_progress: config.report_progress,
+            basic_block_count: 0,
+            clock: Clock::new(config.isolated_op == IsolatedOp::Allow),
+            #[cfg(unix)]
+            external_so_lib: config.external_so_file.as_ref().map(|lib_file_path| {
+                let target_triple = layout_cx.tcx.sess.opts.target_triple.triple();
+                // Check if host target == the session target.
+                if env!("TARGET") != target_triple {
+                    panic!(
+                        "calling external C functions in linked .so file requires host and target to be the same: host={}, target={}",
+                        env!("TARGET"),
+                        target_triple,
+                    );
+                }
+                // Note: it is the user's responsibility to provide a correct SO file.
+                // WATCH OUT: If an invalid/incorrect SO file is specified, this can cause
+                // undefined behaviour in Miri itself!
+                (
+                    unsafe {
+                        libloading::Library::new(lib_file_path)
+                            .expect("failed to read specified extern shared object file")
+                    },
+                    lib_file_path.clone(),
+                )
+            }),
+            gc_interval: config.gc_interval,
+            since_gc: 0,
+        }
+    }
+
+    pub(crate) fn late_init(
+        this: &mut MiriInterpCx<'mir, 'tcx>,
+        config: &MiriConfig,
+    ) -> InterpResult<'tcx> {
+        EnvVars::init(this, config)?;
+        MiriMachine::init_extern_statics(this)?;
+        ThreadManager::init(this);
+        Ok(())
+    }
+
+    fn add_extern_static(
+        this: &mut MiriInterpCx<'mir, 'tcx>,
+        name: &str,
+        ptr: Pointer<Option<Provenance>>,
+    ) {
+        // This got just allocated, so there definitely is a pointer here.
+        let ptr = ptr.into_pointer_or_addr().unwrap();
+        this.machine.extern_statics.try_insert(Symbol::intern(name), ptr).unwrap();
+    }
+
+    fn alloc_extern_static(
+        this: &mut MiriInterpCx<'mir, 'tcx>,
+        name: &str,
+        val: ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let place = this.allocate(val.layout, MiriMemoryKind::ExternStatic.into())?;
+        this.write_immediate(*val, &place.into())?;
+        Self::add_extern_static(this, name, place.ptr);
+        Ok(())
+    }
+
+    /// Sets up the "extern statics" for this machine.
+    fn init_extern_statics(this: &mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx> {
+        match this.tcx.sess.target.os.as_ref() {
+            "linux" => {
+                // "environ"
+                Self::add_extern_static(
+                    this,
+                    "environ",
+                    this.machine.env_vars.environ.unwrap().ptr,
+                );
+                // A couple zero-initialized pointer-sized extern statics.
+                // Most of them are for weak symbols, which we all set to null (indicating that the
+                // symbol is not supported, and triggering fallback code which ends up calling a
+                // syscall that we do support).
+                for name in &["__cxa_thread_atexit_impl", "getrandom", "statx", "__clock_gettime64"]
+                {
+                    let val = ImmTy::from_int(0, this.machine.layouts.usize);
+                    Self::alloc_extern_static(this, name, val)?;
+                }
+            }
+            "freebsd" => {
+                // "environ"
+                Self::add_extern_static(
+                    this,
+                    "environ",
+                    this.machine.env_vars.environ.unwrap().ptr,
+                );
+            }
+            "android" => {
+                // "signal"
+                let layout = this.machine.layouts.const_raw_ptr;
+                let dlsym = Dlsym::from_str("signal".as_bytes(), &this.tcx.sess.target.os)?
+                    .expect("`signal` must be an actual dlsym on android");
+                let ptr = this.create_fn_alloc_ptr(FnVal::Other(dlsym));
+                let val = ImmTy::from_scalar(Scalar::from_pointer(ptr, this), layout);
+                Self::alloc_extern_static(this, "signal", val)?;
+                // A couple zero-initialized pointer-sized extern statics.
+                // Most of them are for weak symbols, which we all set to null (indicating that the
+                // symbol is not supported, and triggering fallback code.)
+                for name in &["bsd_signal"] {
+                    let val = ImmTy::from_int(0, this.machine.layouts.usize);
+                    Self::alloc_extern_static(this, name, val)?;
+                }
+            }
+            "windows" => {
+                // "_tls_used"
+                // This is some obscure hack that is part of the Windows TLS story. It's a `u8`.
+                let val = ImmTy::from_int(0, this.machine.layouts.u8);
+                Self::alloc_extern_static(this, "_tls_used", val)?;
+            }
+            _ => {} // No "extern statics" supported on this target
+        }
+        Ok(())
+    }
+
+    pub(crate) fn communicate(&self) -> bool {
+        self.isolated_op == IsolatedOp::Allow
+    }
+
+    /// Check whether the stack frame that this `FrameInfo` refers to is part of a local crate.
+    pub(crate) fn is_local(&self, frame: &FrameInfo<'_>) -> bool {
+        let def_id = frame.instance.def_id();
+        def_id.is_local() || self.local_crates.contains(&def_id.krate)
+    }
+}
+
+/// A rustc InterpCx for Miri.
+pub type MiriInterpCx<'mir, 'tcx> = InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>;
+
+/// A little trait that's useful to be inherited by extension traits.
+pub trait MiriInterpCxExt<'mir, 'tcx> {
+    fn eval_context_ref<'a>(&'a self) -> &'a MiriInterpCx<'mir, 'tcx>;
+    fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriInterpCx<'mir, 'tcx>;
+}
+impl<'mir, 'tcx> MiriInterpCxExt<'mir, 'tcx> for MiriInterpCx<'mir, 'tcx> {
+    #[inline(always)]
+    fn eval_context_ref(&self) -> &MiriInterpCx<'mir, 'tcx> {
+        self
+    }
+    #[inline(always)]
+    fn eval_context_mut(&mut self) -> &mut MiriInterpCx<'mir, 'tcx> {
+        self
+    }
+}
+
+/// Machine hook implementations.
+impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
+    type MemoryKind = MiriMemoryKind;
+    type ExtraFnVal = Dlsym;
+
+    type FrameExtra = FrameData<'tcx>;
+    type AllocExtra = AllocExtra;
+
+    type Provenance = Provenance;
+    type ProvenanceExtra = ProvenanceExtra;
+
+    type MemoryMap = MonoHashMap<
+        AllocId,
+        (MemoryKind<MiriMemoryKind>, Allocation<Provenance, Self::AllocExtra>),
+    >;
+
+    const GLOBAL_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Global);
+
+    const PANIC_ON_ALLOC_FAIL: bool = false;
+
+    #[inline(always)]
+    fn enforce_alignment(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
+        ecx.machine.check_alignment != AlignmentCheck::None
+    }
+
+    #[inline(always)]
+    fn use_addr_for_alignment_check(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
+        ecx.machine.check_alignment == AlignmentCheck::Int
+    }
+
+    #[inline(always)]
+    fn enforce_validity(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
+        ecx.machine.validate
+    }
+
+    #[inline(always)]
+    fn enforce_abi(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
+        ecx.machine.enforce_abi
+    }
+
+    #[inline(always)]
+    fn checked_binop_checks_overflow(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
+        ecx.tcx.sess.overflow_checks()
+    }
+
+    #[inline(always)]
+    fn find_mir_or_eval_fn(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        instance: ty::Instance<'tcx>,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
+        ecx.find_mir_or_eval_fn(instance, abi, args, dest, ret, unwind)
+    }
+
+    #[inline(always)]
+    fn call_extra_fn(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        fn_val: Dlsym,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        _unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx> {
+        ecx.call_dlsym(fn_val, abi, args, dest, ret)
+    }
+
+    #[inline(always)]
+    fn call_intrinsic(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        instance: ty::Instance<'tcx>,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx> {
+        ecx.call_intrinsic(instance, args, dest, ret, unwind)
+    }
+
+    #[inline(always)]
+    fn assert_panic(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        msg: &mir::AssertMessage<'tcx>,
+        unwind: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        ecx.assert_panic(msg, unwind)
+    }
+
+    #[inline(always)]
+    fn abort(_ecx: &mut MiriInterpCx<'mir, 'tcx>, msg: String) -> InterpResult<'tcx, !> {
+        throw_machine_stop!(TerminationInfo::Abort(msg))
+    }
+
+    #[inline(always)]
+    fn binary_ptr_op(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        bin_op: mir::BinOp,
+        left: &ImmTy<'tcx, Provenance>,
+        right: &ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, (Scalar<Provenance>, bool, Ty<'tcx>)> {
+        ecx.binary_ptr_op(bin_op, left, right)
+    }
+
+    fn thread_local_static_base_pointer(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        def_id: DefId,
+    ) -> InterpResult<'tcx, Pointer<Provenance>> {
+        ecx.get_or_create_thread_local_alloc(def_id)
+    }
+
+    fn extern_static_base_pointer(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        def_id: DefId,
+    ) -> InterpResult<'tcx, Pointer<Provenance>> {
+        let link_name = ecx.item_link_name(def_id);
+        if let Some(&ptr) = ecx.machine.extern_statics.get(&link_name) {
+            // Various parts of the engine rely on `get_alloc_info` for size and alignment
+            // information. That uses the type information of this static.
+            // Make sure it matches the Miri allocation for this.
+            let Provenance::Concrete { alloc_id, .. } = ptr.provenance else {
+                panic!("extern_statics cannot contain wildcards")
+            };
+            let (shim_size, shim_align, _kind) = ecx.get_alloc_info(alloc_id);
+            let extern_decl_layout =
+                ecx.tcx.layout_of(ty::ParamEnv::empty().and(ecx.tcx.type_of(def_id))).unwrap();
+            if extern_decl_layout.size != shim_size || extern_decl_layout.align.abi != shim_align {
+                throw_unsup_format!(
+                    "`extern` static `{name}` from crate `{krate}` has been declared \
+                    with a size of {decl_size} bytes and alignment of {decl_align} bytes, \
+                    but Miri emulates it via an extern static shim \
+                    with a size of {shim_size} bytes and alignment of {shim_align} bytes",
+                    name = ecx.tcx.def_path_str(def_id),
+                    krate = ecx.tcx.crate_name(def_id.krate),
+                    decl_size = extern_decl_layout.size.bytes(),
+                    decl_align = extern_decl_layout.align.abi.bytes(),
+                    shim_size = shim_size.bytes(),
+                    shim_align = shim_align.bytes(),
+                )
+            }
+            Ok(ptr)
+        } else {
+            throw_unsup_format!(
+                "`extern` static `{name}` from crate `{krate}` is not supported by Miri",
+                name = ecx.tcx.def_path_str(def_id),
+                krate = ecx.tcx.crate_name(def_id.krate),
+            )
+        }
+    }
+
+    fn adjust_allocation<'b>(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        id: AllocId,
+        alloc: Cow<'b, Allocation>,
+        kind: Option<MemoryKind<Self::MemoryKind>>,
+    ) -> InterpResult<'tcx, Cow<'b, Allocation<Self::Provenance, Self::AllocExtra>>> {
+        let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
+        if ecx.machine.tracked_alloc_ids.contains(&id) {
+            ecx.emit_diagnostic(NonHaltingDiagnostic::CreatedAlloc(
+                id,
+                alloc.size(),
+                alloc.align,
+                kind,
+            ));
+        }
+
+        let alloc = alloc.into_owned();
+        let stacks = ecx.machine.stacked_borrows.as_ref().map(|stacked_borrows| {
+            Stacks::new_allocation(
+                id,
+                alloc.size(),
+                stacked_borrows,
+                kind,
+                ecx.machine.current_span(),
+            )
+        });
+        let race_alloc = ecx.machine.data_race.as_ref().map(|data_race| {
+            data_race::AllocExtra::new_allocation(
+                data_race,
+                &ecx.machine.threads,
+                alloc.size(),
+                kind,
+            )
+        });
+        let buffer_alloc = ecx.machine.weak_memory.then(weak_memory::AllocExtra::new_allocation);
+        let alloc: Allocation<Provenance, Self::AllocExtra> = alloc.adjust_from_tcx(
+            &ecx.tcx,
+            AllocExtra {
+                stacked_borrows: stacks.map(RefCell::new),
+                data_race: race_alloc,
+                weak_memory: buffer_alloc,
+            },
+            |ptr| ecx.global_base_pointer(ptr),
+        )?;
+        Ok(Cow::Owned(alloc))
+    }
+
+    fn adjust_alloc_base_pointer(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        ptr: Pointer<AllocId>,
+    ) -> Pointer<Provenance> {
+        if cfg!(debug_assertions) {
+            // The machine promises to never call us on thread-local or extern statics.
+            let alloc_id = ptr.provenance;
+            match ecx.tcx.try_get_global_alloc(alloc_id) {
+                Some(GlobalAlloc::Static(def_id)) if ecx.tcx.is_thread_local_static(def_id) => {
+                    panic!("adjust_alloc_base_pointer called on thread-local static")
+                }
+                Some(GlobalAlloc::Static(def_id)) if ecx.tcx.is_foreign_item(def_id) => {
+                    panic!("adjust_alloc_base_pointer called on extern static")
+                }
+                _ => {}
+            }
+        }
+        let absolute_addr = intptrcast::GlobalStateInner::rel_ptr_to_addr(ecx, ptr);
+        let sb_tag = if let Some(stacked_borrows) = &ecx.machine.stacked_borrows {
+            stacked_borrows.borrow_mut().base_ptr_tag(ptr.provenance, &ecx.machine)
+        } else {
+            // Value does not matter, SB is disabled
+            SbTag::default()
+        };
+        Pointer::new(
+            Provenance::Concrete { alloc_id: ptr.provenance, sb: sb_tag },
+            Size::from_bytes(absolute_addr),
+        )
+    }
+
+    #[inline(always)]
+    fn ptr_from_addr_cast(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        addr: u64,
+    ) -> InterpResult<'tcx, Pointer<Option<Self::Provenance>>> {
+        intptrcast::GlobalStateInner::ptr_from_addr_cast(ecx, addr)
+    }
+
+    fn expose_ptr(
+        ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        ptr: Pointer<Self::Provenance>,
+    ) -> InterpResult<'tcx> {
+        match ptr.provenance {
+            Provenance::Concrete { alloc_id, sb } =>
+                intptrcast::GlobalStateInner::expose_ptr(ecx, alloc_id, sb),
+            Provenance::Wildcard => {
+                // No need to do anything for wildcard pointers as
+                // their provenances have already been previously exposed.
+                Ok(())
+            }
+        }
+    }
+
+    /// Convert a pointer with provenance into an allocation-offset pair,
+    /// or a `None` with an absolute address if that conversion is not possible.
+    fn ptr_get_alloc(
+        ecx: &MiriInterpCx<'mir, 'tcx>,
+        ptr: Pointer<Self::Provenance>,
+    ) -> Option<(AllocId, Size, Self::ProvenanceExtra)> {
+        let rel = intptrcast::GlobalStateInner::abs_ptr_to_rel(ecx, ptr);
+
+        rel.map(|(alloc_id, size)| {
+            let sb = match ptr.provenance {
+                Provenance::Concrete { sb, .. } => ProvenanceExtra::Concrete(sb),
+                Provenance::Wildcard => ProvenanceExtra::Wildcard,
+            };
+            (alloc_id, size, sb)
+        })
+    }
+
+    #[inline(always)]
+    fn before_memory_read(
+        _tcx: TyCtxt<'tcx>,
+        machine: &Self,
+        alloc_extra: &AllocExtra,
+        (alloc_id, prov_extra): (AllocId, Self::ProvenanceExtra),
+        range: AllocRange,
+    ) -> InterpResult<'tcx> {
+        if let Some(data_race) = &alloc_extra.data_race {
+            data_race.read(
+                alloc_id,
+                range,
+                machine.data_race.as_ref().unwrap(),
+                &machine.threads,
+            )?;
+        }
+        if let Some(stacked_borrows) = &alloc_extra.stacked_borrows {
+            stacked_borrows.borrow_mut().before_memory_read(
+                alloc_id,
+                prov_extra,
+                range,
+                machine.stacked_borrows.as_ref().unwrap(),
+                machine.current_span(),
+                &machine.threads,
+            )?;
+        }
+        if let Some(weak_memory) = &alloc_extra.weak_memory {
+            weak_memory.memory_accessed(range, machine.data_race.as_ref().unwrap());
+        }
+        Ok(())
+    }
+
+    #[inline(always)]
+    fn before_memory_write(
+        _tcx: TyCtxt<'tcx>,
+        machine: &mut Self,
+        alloc_extra: &mut AllocExtra,
+        (alloc_id, prov_extra): (AllocId, Self::ProvenanceExtra),
+        range: AllocRange,
+    ) -> InterpResult<'tcx> {
+        if let Some(data_race) = &mut alloc_extra.data_race {
+            data_race.write(
+                alloc_id,
+                range,
+                machine.data_race.as_mut().unwrap(),
+                &machine.threads,
+            )?;
+        }
+        if let Some(stacked_borrows) = &mut alloc_extra.stacked_borrows {
+            stacked_borrows.get_mut().before_memory_write(
+                alloc_id,
+                prov_extra,
+                range,
+                machine.stacked_borrows.as_ref().unwrap(),
+                machine.current_span(),
+                &machine.threads,
+            )?;
+        }
+        if let Some(weak_memory) = &alloc_extra.weak_memory {
+            weak_memory.memory_accessed(range, machine.data_race.as_ref().unwrap());
+        }
+        Ok(())
+    }
+
+    #[inline(always)]
+    fn before_memory_deallocation(
+        _tcx: TyCtxt<'tcx>,
+        machine: &mut Self,
+        alloc_extra: &mut AllocExtra,
+        (alloc_id, prove_extra): (AllocId, Self::ProvenanceExtra),
+        range: AllocRange,
+    ) -> InterpResult<'tcx> {
+        if machine.tracked_alloc_ids.contains(&alloc_id) {
+            machine.emit_diagnostic(NonHaltingDiagnostic::FreedAlloc(alloc_id));
+        }
+        if let Some(data_race) = &mut alloc_extra.data_race {
+            data_race.deallocate(
+                alloc_id,
+                range,
+                machine.data_race.as_mut().unwrap(),
+                &machine.threads,
+            )?;
+        }
+        if let Some(stacked_borrows) = &mut alloc_extra.stacked_borrows {
+            stacked_borrows.get_mut().before_memory_deallocation(
+                alloc_id,
+                prove_extra,
+                range,
+                machine.stacked_borrows.as_ref().unwrap(),
+                machine.current_span(),
+                &machine.threads,
+            )
+        } else {
+            Ok(())
+        }
+    }
+
+    #[inline(always)]
+    fn retag(
+        ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        kind: mir::RetagKind,
+        place: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        if ecx.machine.stacked_borrows.is_some() { ecx.retag(kind, place) } else { Ok(()) }
+    }
+
+    #[inline(always)]
+    fn init_frame_extra(
+        ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        frame: Frame<'mir, 'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>> {
+        // Start recording our event before doing anything else
+        let timing = if let Some(profiler) = ecx.machine.profiler.as_ref() {
+            let fn_name = frame.instance.to_string();
+            let entry = ecx.machine.string_cache.entry(fn_name.clone());
+            let name = entry.or_insert_with(|| profiler.alloc_string(&*fn_name));
+
+            Some(profiler.start_recording_interval_event_detached(
+                *name,
+                measureme::EventId::from_label(*name),
+                ecx.get_active_thread().to_u32(),
+            ))
+        } else {
+            None
+        };
+
+        let stacked_borrows = ecx.machine.stacked_borrows.as_ref();
+
+        let extra = FrameData {
+            stacked_borrows: stacked_borrows.map(|sb| sb.borrow_mut().new_frame(&ecx.machine)),
+            catch_unwind: None,
+            timing,
+        };
+        Ok(frame.with_extra(extra))
+    }
+
+    fn stack<'a>(
+        ecx: &'a InterpCx<'mir, 'tcx, Self>,
+    ) -> &'a [Frame<'mir, 'tcx, Self::Provenance, Self::FrameExtra>] {
+        ecx.active_thread_stack()
+    }
+
+    fn stack_mut<'a>(
+        ecx: &'a mut InterpCx<'mir, 'tcx, Self>,
+    ) -> &'a mut Vec<Frame<'mir, 'tcx, Self::Provenance, Self::FrameExtra>> {
+        ecx.active_thread_stack_mut()
+    }
+
+    fn before_terminator(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
+        ecx.machine.basic_block_count += 1u64; // a u64 that is only incremented by 1 will "never" overflow
+        ecx.machine.since_gc += 1;
+        // Possibly report our progress.
+        if let Some(report_progress) = ecx.machine.report_progress {
+            if ecx.machine.basic_block_count % u64::from(report_progress) == 0 {
+                ecx.emit_diagnostic(NonHaltingDiagnostic::ProgressReport {
+                    block_count: ecx.machine.basic_block_count,
+                });
+            }
+        }
+
+        // Search for SbTags to find all live pointers, then remove all other tags from borrow
+        // stacks.
+        // When debug assertions are enabled, run the GC as often as possible so that any cases
+        // where it mistakenly removes an important tag become visible.
+        if ecx.machine.gc_interval > 0 && ecx.machine.since_gc >= ecx.machine.gc_interval {
+            ecx.machine.since_gc = 0;
+            ecx.garbage_collect_tags()?;
+        }
+
+        // These are our preemption points.
+        ecx.maybe_preempt_active_thread();
+
+        // Make sure some time passes.
+        ecx.machine.clock.tick();
+
+        Ok(())
+    }
+
+    #[inline(always)]
+    fn after_stack_push(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
+        if ecx.machine.stacked_borrows.is_some() { ecx.retag_return_place() } else { Ok(()) }
+    }
+
+    #[inline(always)]
+    fn after_stack_pop(
+        ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        mut frame: Frame<'mir, 'tcx, Provenance, FrameData<'tcx>>,
+        unwinding: bool,
+    ) -> InterpResult<'tcx, StackPopJump> {
+        let timing = frame.extra.timing.take();
+        if let Some(stacked_borrows) = &ecx.machine.stacked_borrows {
+            stacked_borrows.borrow_mut().end_call(&frame.extra);
+        }
+        let res = ecx.handle_stack_pop_unwind(frame.extra, unwinding);
+        if let Some(profiler) = ecx.machine.profiler.as_ref() {
+            profiler.finish_recording_interval_event(timing.unwrap());
+        }
+        res
+    }
+}
diff --git a/src/tools/miri/src/mono_hash_map.rs b/src/tools/miri/src/mono_hash_map.rs
new file mode 100644
index 000000000000..45057632df9b
--- /dev/null
+++ b/src/tools/miri/src/mono_hash_map.rs
@@ -0,0 +1,110 @@
+//! This is a "monotonic `FxHashMap`": A `FxHashMap` that, when shared, can be pushed to but not
+//! otherwise mutated. We also box items in the map. This means we can safely provide
+//! shared references into existing items in the `FxHashMap`, because they will not be dropped
+//! (from being removed) or moved (because they are boxed).
+//! The API is is completely tailored to what `memory.rs` needs. It is still in
+//! a separate file to minimize the amount of code that has to care about the unsafety.
+
+use std::borrow::Borrow;
+use std::cell::RefCell;
+use std::collections::hash_map::Entry;
+use std::hash::Hash;
+
+use rustc_data_structures::fx::FxHashMap;
+
+use crate::AllocMap;
+
+#[derive(Debug, Clone)]
+pub struct MonoHashMap<K: Hash + Eq, V>(RefCell<FxHashMap<K, Box<V>>>);
+
+impl<K: Hash + Eq, V> MonoHashMap<K, V> {
+    /// This function exists for priroda to be able to iterate over all evaluator memory.
+    ///
+    /// The function is somewhat roundabout with the closure argument because internally the
+    /// `MonoHashMap` uses a `RefCell`. When iterating over the `FxHashMap` inside the `RefCell`,
+    /// we need to keep a borrow to the `FxHashMap` inside the iterator. The borrow is only alive
+    /// as long as the `Ref` returned by `RefCell::borrow()` is alive. So we can't return the
+    /// iterator, as that would drop the `Ref`. We can't return both, as it's not possible in Rust
+    /// to have a struct/tuple with a field that refers to another field.
+    pub fn iter<T>(&self, f: impl FnOnce(&mut dyn Iterator<Item = (&K, &V)>) -> T) -> T {
+        f(&mut self.0.borrow().iter().map(|(k, v)| (k, &**v)))
+    }
+}
+
+impl<K: Hash + Eq, V> Default for MonoHashMap<K, V> {
+    fn default() -> Self {
+        MonoHashMap(RefCell::new(Default::default()))
+    }
+}
+
+impl<K: Hash + Eq, V> AllocMap<K, V> for MonoHashMap<K, V> {
+    #[inline(always)]
+    fn contains_key<Q: ?Sized + Hash + Eq>(&mut self, k: &Q) -> bool
+    where
+        K: Borrow<Q>,
+    {
+        self.0.get_mut().contains_key(k)
+    }
+
+    #[inline(always)]
+    fn insert(&mut self, k: K, v: V) -> Option<V> {
+        self.0.get_mut().insert(k, Box::new(v)).map(|x| *x)
+    }
+
+    #[inline(always)]
+    fn remove<Q: ?Sized + Hash + Eq>(&mut self, k: &Q) -> Option<V>
+    where
+        K: Borrow<Q>,
+    {
+        self.0.get_mut().remove(k).map(|x| *x)
+    }
+
+    #[inline(always)]
+    fn filter_map_collect<T>(&self, mut f: impl FnMut(&K, &V) -> Option<T>) -> Vec<T> {
+        self.0.borrow().iter().filter_map(move |(k, v)| f(k, v)).collect()
+    }
+
+    /// The most interesting method: Providing a shared reference without
+    /// holding the `RefCell` open, and inserting new data if the key
+    /// is not used yet.
+    /// `vacant` is called if the key is not found in the map;
+    /// if it returns a reference, that is used directly, if it
+    /// returns owned data, that is put into the map and returned.
+    #[inline(always)]
+    fn get_or<E>(&self, k: K, vacant: impl FnOnce() -> Result<V, E>) -> Result<&V, E> {
+        // We cannot hold borrow_mut while calling `vacant`, since that might have to do lookups in this very map.
+        if let Some(v) = self.0.borrow().get(&k) {
+            let val: *const V = &**v;
+            // This is safe because `val` points into a `Box`, that we know will not move and
+            // will also not be dropped as long as the shared reference `self` is live.
+            return unsafe { Ok(&*val) };
+        }
+        let new_val = Box::new(vacant()?);
+        let val: *const V = &**self.0.borrow_mut().try_insert(k, new_val).ok().unwrap();
+        // This is safe because `val` points into a `Box`, that we know will not move and
+        // will also not be dropped as long as the shared reference `self` is live.
+        unsafe { Ok(&*val) }
+    }
+
+    /// Read-only lookup (avoid read-acquiring the RefCell).
+    fn get(&self, k: K) -> Option<&V> {
+        let val: *const V = match self.0.borrow().get(&k) {
+            Some(v) => &**v,
+            None => return None,
+        };
+        // This is safe because `val` points into a `Box`, that we know will not move and
+        // will also not be dropped as long as the shared reference `self` is live.
+        unsafe { Some(&*val) }
+    }
+
+    #[inline(always)]
+    fn get_mut_or<E>(&mut self, k: K, vacant: impl FnOnce() -> Result<V, E>) -> Result<&mut V, E> {
+        match self.0.get_mut().entry(k) {
+            Entry::Occupied(e) => Ok(e.into_mut()),
+            Entry::Vacant(e) => {
+                let v = vacant()?;
+                Ok(e.insert(Box::new(v)))
+            }
+        }
+    }
+}
diff --git a/src/tools/miri/src/operator.rs b/src/tools/miri/src/operator.rs
new file mode 100644
index 000000000000..a0ef7fcad16d
--- /dev/null
+++ b/src/tools/miri/src/operator.rs
@@ -0,0 +1,90 @@
+use log::trace;
+
+use rustc_middle::{mir, ty::Ty};
+use rustc_target::abi::Size;
+
+use crate::*;
+
+pub trait EvalContextExt<'tcx> {
+    fn binary_ptr_op(
+        &self,
+        bin_op: mir::BinOp,
+        left: &ImmTy<'tcx, Provenance>,
+        right: &ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, (Scalar<Provenance>, bool, Ty<'tcx>)>;
+}
+
+impl<'mir, 'tcx> EvalContextExt<'tcx> for super::MiriInterpCx<'mir, 'tcx> {
+    fn binary_ptr_op(
+        &self,
+        bin_op: mir::BinOp,
+        left: &ImmTy<'tcx, Provenance>,
+        right: &ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, (Scalar<Provenance>, bool, Ty<'tcx>)> {
+        use rustc_middle::mir::BinOp::*;
+
+        trace!("ptr_op: {:?} {:?} {:?}", *left, bin_op, *right);
+
+        Ok(match bin_op {
+            Eq | Ne | Lt | Le | Gt | Ge => {
+                assert_eq!(left.layout.abi, right.layout.abi); // types an differ, e.g. fn ptrs with different `for`
+                let size = self.pointer_size();
+                // Just compare the bits. ScalarPairs are compared lexicographically.
+                // We thus always compare pairs and simply fill scalars up with 0.
+                let left = match **left {
+                    Immediate::Scalar(l) => (l.to_bits(size)?, 0),
+                    Immediate::ScalarPair(l1, l2) => (l1.to_bits(size)?, l2.to_bits(size)?),
+                    Immediate::Uninit => panic!("we should never see uninit data here"),
+                };
+                let right = match **right {
+                    Immediate::Scalar(r) => (r.to_bits(size)?, 0),
+                    Immediate::ScalarPair(r1, r2) => (r1.to_bits(size)?, r2.to_bits(size)?),
+                    Immediate::Uninit => panic!("we should never see uninit data here"),
+                };
+                let res = match bin_op {
+                    Eq => left == right,
+                    Ne => left != right,
+                    Lt => left < right,
+                    Le => left <= right,
+                    Gt => left > right,
+                    Ge => left >= right,
+                    _ => bug!(),
+                };
+                (Scalar::from_bool(res), false, self.tcx.types.bool)
+            }
+
+            Offset => {
+                assert!(left.layout.ty.is_unsafe_ptr());
+                let ptr = left.to_scalar().to_pointer(self)?;
+                let offset = right.to_scalar().to_machine_isize(self)?;
+
+                let pointee_ty =
+                    left.layout.ty.builtin_deref(true).expect("Offset called on non-ptr type").ty;
+                let ptr = self.ptr_offset_inbounds(ptr, pointee_ty, offset)?;
+                (Scalar::from_maybe_pointer(ptr, self), false, left.layout.ty)
+            }
+
+            // Some more operations are possible with atomics.
+            // The return value always has the provenance of the *left* operand.
+            Add | Sub | BitOr | BitAnd | BitXor => {
+                assert!(left.layout.ty.is_unsafe_ptr());
+                assert!(right.layout.ty.is_unsafe_ptr());
+                let ptr = left.to_scalar().to_pointer(self)?;
+                // We do the actual operation with usize-typed scalars.
+                let left = ImmTy::from_uint(ptr.addr().bytes(), self.machine.layouts.usize);
+                let right = ImmTy::from_uint(
+                    right.to_scalar().to_machine_usize(self)?,
+                    self.machine.layouts.usize,
+                );
+                let (result, overflowing, _ty) =
+                    self.overflowing_binary_op(bin_op, &left, &right)?;
+                // Construct a new pointer with the provenance of `ptr` (the LHS).
+                let result_ptr =
+                    Pointer::new(ptr.provenance, Size::from_bytes(result.to_machine_usize(self)?));
+                (Scalar::from_maybe_pointer(result_ptr, self), overflowing, left.layout.ty)
+            }
+
+            _ => span_bug!(self.cur_span(), "Invalid operator on pointers: {:?}", bin_op),
+        })
+    }
+}
diff --git a/src/tools/miri/src/range_map.rs b/src/tools/miri/src/range_map.rs
new file mode 100644
index 000000000000..c77ea63b0873
--- /dev/null
+++ b/src/tools/miri/src/range_map.rs
@@ -0,0 +1,300 @@
+//! Implements a map from integer indices to data.
+//! Rather than storing data for every index, internally, this maps entire ranges to the data.
+//! To this end, the APIs all work on ranges, not on individual integers. Ranges are split as
+//! necessary (e.g., when [0,5) is first associated with X, and then [1,2) is mutated).
+//! Users must not depend on whether a range is coalesced or not, even though this is observable
+//! via the iteration APIs.
+
+use std::ops;
+
+use rustc_target::abi::Size;
+
+#[derive(Clone, Debug)]
+struct Elem<T> {
+    /// The range covered by this element; never empty.
+    range: ops::Range<u64>,
+    /// The data stored for this element.
+    data: T,
+}
+#[derive(Clone, Debug)]
+pub struct RangeMap<T> {
+    v: Vec<Elem<T>>,
+}
+
+impl<T> RangeMap<T> {
+    /// Creates a new `RangeMap` for the given size, and with the given initial value used for
+    /// the entire range.
+    #[inline(always)]
+    pub fn new(size: Size, init: T) -> RangeMap<T> {
+        let size = size.bytes();
+        let mut map = RangeMap { v: Vec::new() };
+        if size > 0 {
+            map.v.push(Elem { range: 0..size, data: init });
+        }
+        map
+    }
+
+    /// Finds the index containing the given offset.
+    fn find_offset(&self, offset: u64) -> usize {
+        // We do a binary search.
+        let mut left = 0usize; // inclusive
+        let mut right = self.v.len(); // exclusive
+        loop {
+            debug_assert!(left < right, "find_offset: offset {} is out-of-bounds", offset);
+            let candidate = left.checked_add(right).unwrap() / 2;
+            let elem = &self.v[candidate];
+            if offset < elem.range.start {
+                // We are too far right (offset is further left).
+                debug_assert!(candidate < right); // we are making progress
+                right = candidate;
+            } else if offset >= elem.range.end {
+                // We are too far left (offset is further right).
+                debug_assert!(candidate >= left); // we are making progress
+                left = candidate + 1;
+            } else {
+                // This is it!
+                return candidate;
+            }
+        }
+    }
+
+    /// Provides read-only iteration over everything in the given range. This does
+    /// *not* split items if they overlap with the edges. Do not use this to mutate
+    /// through interior mutability.
+    ///
+    /// The iterator also provides the offset of the given element.
+    pub fn iter(&self, offset: Size, len: Size) -> impl Iterator<Item = (Size, &T)> {
+        let offset = offset.bytes();
+        let len = len.bytes();
+        // Compute a slice starting with the elements we care about.
+        let slice: &[Elem<T>] = if len == 0 {
+            // We just need any empty iterator. We don't even want to
+            // yield the element that surrounds this position.
+            &[]
+        } else {
+            let first_idx = self.find_offset(offset);
+            &self.v[first_idx..]
+        };
+        // The first offset that is not included any more.
+        let end = offset + len;
+        assert!(
+            end <= self.v.last().unwrap().range.end,
+            "iterating beyond the bounds of this RangeMap"
+        );
+        slice
+            .iter()
+            .take_while(move |elem| elem.range.start < end)
+            .map(|elem| (Size::from_bytes(elem.range.start), &elem.data))
+    }
+
+    pub fn iter_mut_all(&mut self) -> impl Iterator<Item = &mut T> {
+        self.v.iter_mut().map(|elem| &mut elem.data)
+    }
+
+    // Splits the element situated at the given `index`, such that the 2nd one starts at offset
+    // `split_offset`. Do nothing if the element already starts there.
+    // Returns whether a split was necessary.
+    fn split_index(&mut self, index: usize, split_offset: u64) -> bool
+    where
+        T: Clone,
+    {
+        let elem = &mut self.v[index];
+        if split_offset == elem.range.start || split_offset == elem.range.end {
+            // Nothing to do.
+            return false;
+        }
+        debug_assert!(
+            elem.range.contains(&split_offset),
+            "the `split_offset` is not in the element to be split"
+        );
+
+        // Now we really have to split. Reduce length of first element.
+        let second_range = split_offset..elem.range.end;
+        elem.range.end = split_offset;
+        // Copy the data, and insert second element.
+        let second = Elem { range: second_range, data: elem.data.clone() };
+        self.v.insert(index + 1, second);
+        true
+    }
+
+    /// Provides mutable iteration over everything in the given range. As a side-effect,
+    /// this will split entries in the map that are only partially hit by the given range,
+    /// to make sure that when they are mutated, the effect is constrained to the given range.
+    /// Moreover, this will opportunistically merge neighbouring equal blocks.
+    ///
+    /// The iterator also provides the offset of the given element.
+    pub fn iter_mut(&mut self, offset: Size, len: Size) -> impl Iterator<Item = (Size, &mut T)>
+    where
+        T: Clone + PartialEq,
+    {
+        let offset = offset.bytes();
+        let len = len.bytes();
+        // Compute a slice containing exactly the elements we care about
+        let slice: &mut [Elem<T>] = if len == 0 {
+            // We just need any empty iterator. We don't even want to
+            // yield the element that surrounds this position, nor do
+            // any splitting.
+            &mut []
+        } else {
+            // Make sure we got a clear beginning
+            let mut first_idx = self.find_offset(offset);
+            if self.split_index(first_idx, offset) {
+                // The newly created 2nd element is ours
+                first_idx += 1;
+            }
+            // No more mutation.
+            let first_idx = first_idx;
+            // Find our end. Linear scan, but that's ok because the iteration
+            // is doing the same linear scan anyway -- no increase in complexity.
+            // We combine this scan with a scan for duplicates that we can merge, to reduce
+            // the number of elements.
+            // We stop searching after the first "block" of size 1, to avoid spending excessive
+            // amounts of time on the merging.
+            let mut equal_since_idx = first_idx;
+            // Once we see too many non-mergeable blocks, we stop.
+            // The initial value is chosen via... magic. Benchmarking and magic.
+            let mut successful_merge_count = 3usize;
+            // When the loop is done, this is the first excluded element.
+            let mut end_idx = first_idx;
+            loop {
+                // Compute if `end` is the last element we need to look at.
+                let done = self.v[end_idx].range.end >= offset + len;
+                // We definitely need to include `end`, so move the index.
+                end_idx += 1;
+                debug_assert!(
+                    done || end_idx < self.v.len(),
+                    "iter_mut: end-offset {} is out-of-bounds",
+                    offset + len
+                );
+                // see if we want to merge everything in `equal_since..end` (exclusive at the end!)
+                if successful_merge_count > 0 {
+                    if done || self.v[end_idx].data != self.v[equal_since_idx].data {
+                        // Everything in `equal_since..end` was equal. Make them just one element covering
+                        // the entire range.
+                        let removed_elems = end_idx - equal_since_idx - 1; // number of elements that we would remove
+                        if removed_elems > 0 {
+                            // Adjust the range of the first element to cover all of them.
+                            let equal_until = self.v[end_idx - 1].range.end; // end of range of last of the equal elements
+                            self.v[equal_since_idx].range.end = equal_until;
+                            // Delete the rest of them.
+                            self.v.splice(equal_since_idx + 1..end_idx, std::iter::empty());
+                            // Adjust `end_idx` because we made the list shorter.
+                            end_idx -= removed_elems;
+                            // Adjust the count for the cutoff.
+                            successful_merge_count += removed_elems;
+                        } else {
+                            // Adjust the count for the cutoff.
+                            successful_merge_count -= 1;
+                        }
+                        // Go on scanning for the next block starting here.
+                        equal_since_idx = end_idx;
+                    }
+                }
+                // Leave loop if this is the last element.
+                if done {
+                    break;
+                }
+            }
+            // Move to last included instead of first excluded index.
+            let end_idx = end_idx - 1;
+            // We need to split the end as well. Even if this performs a
+            // split, we don't have to adjust our index as we only care about
+            // the first part of the split.
+            self.split_index(end_idx, offset + len);
+            // Now we yield the slice. `end` is inclusive.
+            &mut self.v[first_idx..=end_idx]
+        };
+        slice.iter_mut().map(|elem| (Size::from_bytes(elem.range.start), &mut elem.data))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Query the map at every offset in the range and collect the results.
+    fn to_vec<T: Copy>(map: &RangeMap<T>, offset: u64, len: u64) -> Vec<T> {
+        (offset..offset + len)
+            .into_iter()
+            .map(|i| {
+                map.iter(Size::from_bytes(i), Size::from_bytes(1)).next().map(|(_, &t)| t).unwrap()
+            })
+            .collect()
+    }
+
+    #[test]
+    fn basic_insert() {
+        let mut map = RangeMap::<i32>::new(Size::from_bytes(20), -1);
+        // Insert.
+        for (_, x) in map.iter_mut(Size::from_bytes(10), Size::from_bytes(1)) {
+            *x = 42;
+        }
+        // Check.
+        assert_eq!(to_vec(&map, 10, 1), vec![42]);
+        assert_eq!(map.v.len(), 3);
+
+        // Insert with size 0.
+        for (_, x) in map.iter_mut(Size::from_bytes(10), Size::from_bytes(0)) {
+            *x = 19;
+        }
+        for (_, x) in map.iter_mut(Size::from_bytes(11), Size::from_bytes(0)) {
+            *x = 19;
+        }
+        assert_eq!(to_vec(&map, 10, 2), vec![42, -1]);
+        assert_eq!(map.v.len(), 3);
+    }
+
+    #[test]
+    fn gaps() {
+        let mut map = RangeMap::<i32>::new(Size::from_bytes(20), -1);
+        for (_, x) in map.iter_mut(Size::from_bytes(11), Size::from_bytes(1)) {
+            *x = 42;
+        }
+        for (_, x) in map.iter_mut(Size::from_bytes(15), Size::from_bytes(1)) {
+            *x = 43;
+        }
+        assert_eq!(map.v.len(), 5);
+        assert_eq!(to_vec(&map, 10, 10), vec![-1, 42, -1, -1, -1, 43, -1, -1, -1, -1]);
+
+        for (_, x) in map.iter_mut(Size::from_bytes(10), Size::from_bytes(10)) {
+            if *x < 42 {
+                *x = 23;
+            }
+        }
+        assert_eq!(map.v.len(), 6);
+        assert_eq!(to_vec(&map, 10, 10), vec![23, 42, 23, 23, 23, 43, 23, 23, 23, 23]);
+        assert_eq!(to_vec(&map, 13, 5), vec![23, 23, 43, 23, 23]);
+
+        for (_, x) in map.iter_mut(Size::from_bytes(15), Size::from_bytes(5)) {
+            *x = 19;
+        }
+        assert_eq!(map.v.len(), 6);
+        assert_eq!(to_vec(&map, 10, 10), vec![23, 42, 23, 23, 23, 19, 19, 19, 19, 19]);
+        // Should be seeing two blocks with 19.
+        assert_eq!(
+            map.iter(Size::from_bytes(15), Size::from_bytes(2))
+                .map(|(_, &t)| t)
+                .collect::<Vec<_>>(),
+            vec![19, 19]
+        );
+
+        // A NOP `iter_mut` should trigger merging.
+        for _ in map.iter_mut(Size::from_bytes(15), Size::from_bytes(5)) {}
+        assert_eq!(map.v.len(), 5);
+        assert_eq!(to_vec(&map, 10, 10), vec![23, 42, 23, 23, 23, 19, 19, 19, 19, 19]);
+    }
+
+    #[test]
+    #[should_panic]
+    fn out_of_range_iter_mut() {
+        let mut map = RangeMap::<i32>::new(Size::from_bytes(20), -1);
+        let _ = map.iter_mut(Size::from_bytes(11), Size::from_bytes(11));
+    }
+
+    #[test]
+    #[should_panic]
+    fn out_of_range_iter() {
+        let map = RangeMap::<i32>::new(Size::from_bytes(20), -1);
+        let _ = map.iter(Size::from_bytes(11), Size::from_bytes(11));
+    }
+}
diff --git a/src/tools/miri/src/shims/backtrace.rs b/src/tools/miri/src/shims/backtrace.rs
new file mode 100644
index 000000000000..15987eee537f
--- /dev/null
+++ b/src/tools/miri/src/shims/backtrace.rs
@@ -0,0 +1,254 @@
+use crate::*;
+use rustc_ast::ast::Mutability;
+use rustc_middle::ty::layout::LayoutOf as _;
+use rustc_middle::ty::{self, Instance};
+use rustc_span::{BytePos, Loc, Symbol};
+use rustc_target::{abi::Size, spec::abi::Abi};
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn handle_miri_backtrace_size(
+        &mut self,
+        abi: Abi,
+        link_name: Symbol,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let [flags] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+
+        let flags = this.read_scalar(flags)?.to_u64()?;
+        if flags != 0 {
+            throw_unsup_format!("unknown `miri_backtrace_size` flags {}", flags);
+        }
+
+        let frame_count = this.active_thread_stack().len();
+
+        this.write_scalar(Scalar::from_machine_usize(frame_count.try_into().unwrap(), this), dest)
+    }
+
+    fn handle_miri_get_backtrace(
+        &mut self,
+        abi: Abi,
+        link_name: Symbol,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let tcx = this.tcx;
+
+        let flags = if let Some(flags_op) = args.get(0) {
+            this.read_scalar(flags_op)?.to_u64()?
+        } else {
+            throw_ub_format!("expected at least 1 argument")
+        };
+
+        let mut data = Vec::new();
+        for frame in this.active_thread_stack().iter().rev() {
+            let mut span = frame.current_span();
+            // Match the behavior of runtime backtrace spans
+            // by using a non-macro span in our backtrace. See `FunctionCx::debug_loc`.
+            if span.from_expansion() && !tcx.sess.opts.unstable_opts.debug_macros {
+                span = rustc_span::hygiene::walk_chain(span, frame.body.span.ctxt())
+            }
+            data.push((frame.instance, span.lo()));
+        }
+
+        let ptrs: Vec<_> = data
+            .into_iter()
+            .map(|(instance, pos)| {
+                // We represent a frame pointer by using the `span.lo` value
+                // as an offset into the function's allocation. This gives us an
+                // opaque pointer that we can return to user code, and allows us
+                // to reconstruct the needed frame information in `handle_miri_resolve_frame`.
+                // Note that we never actually read or write anything from/to this pointer -
+                // all of the data is represented by the pointer value itself.
+                let fn_ptr = this.create_fn_alloc_ptr(FnVal::Instance(instance));
+                fn_ptr.wrapping_offset(Size::from_bytes(pos.0), this)
+            })
+            .collect();
+
+        let len: u64 = ptrs.len().try_into().unwrap();
+
+        let ptr_ty = this.machine.layouts.mut_raw_ptr.ty;
+        let array_layout = this.layout_of(tcx.mk_array(ptr_ty, len)).unwrap();
+
+        match flags {
+            // storage for pointers is allocated by miri
+            // deallocating the slice is undefined behavior with a custom global allocator
+            0 => {
+                let [_flags] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+
+                let alloc = this.allocate(array_layout, MiriMemoryKind::Rust.into())?;
+
+                // Write pointers into array
+                for (i, ptr) in ptrs.into_iter().enumerate() {
+                    let place = this.mplace_index(&alloc, i as u64)?;
+
+                    this.write_pointer(ptr, &place.into())?;
+                }
+
+                this.write_immediate(
+                    Immediate::new_slice(Scalar::from_maybe_pointer(alloc.ptr, this), len, this),
+                    dest,
+                )?;
+            }
+            // storage for pointers is allocated by the caller
+            1 => {
+                let [_flags, buf] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+
+                let buf_place = this.deref_operand(buf)?;
+
+                let ptr_layout = this.layout_of(ptr_ty)?;
+
+                for (i, ptr) in ptrs.into_iter().enumerate() {
+                    let offset = ptr_layout.size * i.try_into().unwrap();
+
+                    let op_place = buf_place.offset(offset, ptr_layout, this)?;
+
+                    this.write_pointer(ptr, &op_place.into())?;
+                }
+            }
+            _ => throw_unsup_format!("unknown `miri_get_backtrace` flags {}", flags),
+        };
+
+        Ok(())
+    }
+
+    fn resolve_frame_pointer(
+        &mut self,
+        ptr: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, (Instance<'tcx>, Loc, String, String)> {
+        let this = self.eval_context_mut();
+
+        let ptr = this.read_pointer(ptr)?;
+        // Take apart the pointer, we need its pieces. The offset encodes the span.
+        let (alloc_id, offset, _prov) = this.ptr_get_alloc_id(ptr)?;
+
+        // This has to be an actual global fn ptr, not a dlsym function.
+        let fn_instance = if let Some(GlobalAlloc::Function(instance)) =
+            this.tcx.try_get_global_alloc(alloc_id)
+        {
+            instance
+        } else {
+            throw_ub_format!("expected static function pointer, found {:?}", ptr);
+        };
+
+        let lo =
+            this.tcx.sess.source_map().lookup_char_pos(BytePos(offset.bytes().try_into().unwrap()));
+
+        let name = fn_instance.to_string();
+        let filename = lo.file.name.prefer_remapped().to_string();
+
+        Ok((fn_instance, lo, name, filename))
+    }
+
+    fn handle_miri_resolve_frame(
+        &mut self,
+        abi: Abi,
+        link_name: Symbol,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let [ptr, flags] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+
+        let flags = this.read_scalar(flags)?.to_u64()?;
+
+        let (fn_instance, lo, name, filename) = this.resolve_frame_pointer(ptr)?;
+
+        // Reconstruct the original function pointer,
+        // which we pass to user code.
+        let fn_ptr = this.create_fn_alloc_ptr(FnVal::Instance(fn_instance));
+
+        let num_fields = dest.layout.fields.count();
+
+        if !(4..=5).contains(&num_fields) {
+            // Always mention 5 fields, since the 4-field struct
+            // is deprecated and slated for removal.
+            throw_ub_format!(
+                "bad declaration of miri_resolve_frame - should return a struct with 5 fields"
+            );
+        }
+
+        // `u32` is not enough to fit line/colno, which can be `usize`. It seems unlikely that a
+        // file would have more than 2^32 lines or columns, but whatever, just default to 0.
+        let lineno: u32 = u32::try_from(lo.line).unwrap_or(0);
+        // `lo.col` is 0-based - add 1 to make it 1-based for the caller.
+        let colno: u32 = u32::try_from(lo.col.0.saturating_add(1)).unwrap_or(0);
+
+        let dest = this.force_allocation(dest)?;
+        if let ty::Adt(adt, _) = dest.layout.ty.kind() {
+            if !adt.repr().c() {
+                throw_ub_format!(
+                    "miri_resolve_frame must be declared with a `#[repr(C)]` return type"
+                );
+            }
+        }
+
+        match flags {
+            0 => {
+                // These are "mutable" allocations as we consider them to be owned by the callee.
+                let name_alloc =
+                    this.allocate_str(&name, MiriMemoryKind::Rust.into(), Mutability::Mut);
+                let filename_alloc =
+                    this.allocate_str(&filename, MiriMemoryKind::Rust.into(), Mutability::Mut);
+
+                this.write_immediate(
+                    name_alloc.to_ref(this),
+                    &this.mplace_field(&dest, 0)?.into(),
+                )?;
+                this.write_immediate(
+                    filename_alloc.to_ref(this),
+                    &this.mplace_field(&dest, 1)?.into(),
+                )?;
+            }
+            1 => {
+                this.write_scalar(
+                    Scalar::from_machine_usize(name.len().try_into().unwrap(), this),
+                    &this.mplace_field(&dest, 0)?.into(),
+                )?;
+                this.write_scalar(
+                    Scalar::from_machine_usize(filename.len().try_into().unwrap(), this),
+                    &this.mplace_field(&dest, 1)?.into(),
+                )?;
+            }
+            _ => throw_unsup_format!("unknown `miri_resolve_frame` flags {}", flags),
+        }
+
+        this.write_scalar(Scalar::from_u32(lineno), &this.mplace_field(&dest, 2)?.into())?;
+        this.write_scalar(Scalar::from_u32(colno), &this.mplace_field(&dest, 3)?.into())?;
+
+        // Support a 4-field struct for now - this is deprecated
+        // and slated for removal.
+        if num_fields == 5 {
+            this.write_pointer(fn_ptr, &this.mplace_field(&dest, 4)?.into())?;
+        }
+
+        Ok(())
+    }
+
+    fn handle_miri_resolve_frame_names(
+        &mut self,
+        abi: Abi,
+        link_name: Symbol,
+        args: &[OpTy<'tcx, Provenance>],
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let [ptr, flags, name_ptr, filename_ptr] =
+            this.check_shim(abi, Abi::Rust, link_name, args)?;
+
+        let flags = this.read_scalar(flags)?.to_u64()?;
+        if flags != 0 {
+            throw_unsup_format!("unknown `miri_resolve_frame_names` flags {}", flags);
+        }
+
+        let (_, _, name, filename) = this.resolve_frame_pointer(ptr)?;
+
+        this.write_bytes_ptr(this.read_pointer(name_ptr)?, name.bytes())?;
+        this.write_bytes_ptr(this.read_pointer(filename_ptr)?, filename.bytes())?;
+
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/dlsym.rs b/src/tools/miri/src/shims/dlsym.rs
new file mode 100644
index 000000000000..8bf6d24f85f3
--- /dev/null
+++ b/src/tools/miri/src/shims/dlsym.rs
@@ -0,0 +1,48 @@
+use rustc_middle::mir;
+use rustc_target::spec::abi::Abi;
+
+use crate::helpers::target_os_is_unix;
+use crate::*;
+use shims::unix::dlsym as unix;
+use shims::windows::dlsym as windows;
+
+#[derive(Debug, Copy, Clone)]
+#[allow(non_camel_case_types)]
+pub enum Dlsym {
+    Posix(unix::Dlsym),
+    Windows(windows::Dlsym),
+}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &[u8], target_os: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        let name = &*String::from_utf8_lossy(name);
+        Ok(match target_os {
+            target if target_os_is_unix(target) =>
+                unix::Dlsym::from_str(name, target)?.map(Dlsym::Posix),
+            "windows" => windows::Dlsym::from_str(name)?.map(Dlsym::Windows),
+            os => bug!("dlsym not implemented for target_os {}", os),
+        })
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        match dlsym {
+            Dlsym::Posix(dlsym) =>
+                unix::EvalContextExt::call_dlsym(this, dlsym, abi, args, dest, ret),
+            Dlsym::Windows(dlsym) =>
+                windows::EvalContextExt::call_dlsym(this, dlsym, abi, args, dest, ret),
+        }
+    }
+}
diff --git a/src/tools/miri/src/shims/env.rs b/src/tools/miri/src/shims/env.rs
new file mode 100644
index 000000000000..95051c998e5f
--- /dev/null
+++ b/src/tools/miri/src/shims/env.rs
@@ -0,0 +1,469 @@
+use std::env;
+use std::ffi::{OsStr, OsString};
+use std::io::ErrorKind;
+use std::mem;
+
+use rustc_const_eval::interpret::Pointer;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_target::abi::Size;
+
+use crate::helpers::target_os_is_unix;
+use crate::*;
+
+/// Check whether an operation that writes to a target buffer was successful.
+/// Accordingly select return value.
+/// Local helper function to be used in Windows shims.
+fn windows_check_buffer_size((success, len): (bool, u64)) -> u32 {
+    if success {
+        // If the function succeeds, the return value is the number of characters stored in the target buffer,
+        // not including the terminating null character.
+        u32::try_from(len.checked_sub(1).unwrap()).unwrap()
+    } else {
+        // If the target buffer was not large enough to hold the data, the return value is the buffer size, in characters,
+        // required to hold the string and its terminating null character.
+        u32::try_from(len).unwrap()
+    }
+}
+
+#[derive(Default)]
+pub struct EnvVars<'tcx> {
+    /// Stores pointers to the environment variables. These variables must be stored as
+    /// null-terminated target strings (c_str or wide_str) with the `"{name}={value}"` format.
+    map: FxHashMap<OsString, Pointer<Option<Provenance>>>,
+
+    /// Place where the `environ` static is stored. Lazily initialized, but then never changes.
+    pub(crate) environ: Option<MPlaceTy<'tcx, Provenance>>,
+}
+
+impl<'tcx> EnvVars<'tcx> {
+    pub(crate) fn init<'mir>(
+        ecx: &mut InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
+        config: &MiriConfig,
+    ) -> InterpResult<'tcx> {
+        let target_os = ecx.tcx.sess.target.os.as_ref();
+
+        // Skip the loop entirely if we don't want to forward anything.
+        if ecx.machine.communicate() || !config.forwarded_env_vars.is_empty() {
+            for (name, value) in &config.env {
+                let forward = ecx.machine.communicate()
+                    || config.forwarded_env_vars.iter().any(|v| **v == *name);
+                if forward {
+                    let var_ptr = match target_os {
+                        target if target_os_is_unix(target) =>
+                            alloc_env_var_as_c_str(name.as_ref(), value.as_ref(), ecx)?,
+                        "windows" => alloc_env_var_as_wide_str(name.as_ref(), value.as_ref(), ecx)?,
+                        unsupported =>
+                            throw_unsup_format!(
+                                "environment support for target OS `{}` not yet available",
+                                unsupported
+                            ),
+                    };
+                    ecx.machine.env_vars.map.insert(name.clone(), var_ptr);
+                }
+            }
+        }
+        ecx.update_environ()
+    }
+
+    pub(crate) fn cleanup<'mir>(
+        ecx: &mut InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
+    ) -> InterpResult<'tcx> {
+        // Deallocate individual env vars.
+        let env_vars = mem::take(&mut ecx.machine.env_vars.map);
+        for (_name, ptr) in env_vars {
+            ecx.deallocate_ptr(ptr, None, MiriMemoryKind::Runtime.into())?;
+        }
+        // Deallocate environ var list.
+        let environ = ecx.machine.env_vars.environ.unwrap();
+        let old_vars_ptr = ecx.read_pointer(&environ.into())?;
+        ecx.deallocate_ptr(old_vars_ptr, None, MiriMemoryKind::Runtime.into())?;
+        Ok(())
+    }
+}
+
+fn alloc_env_var_as_c_str<'mir, 'tcx>(
+    name: &OsStr,
+    value: &OsStr,
+    ecx: &mut InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
+) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+    let mut name_osstring = name.to_os_string();
+    name_osstring.push("=");
+    name_osstring.push(value);
+    ecx.alloc_os_str_as_c_str(name_osstring.as_os_str(), MiriMemoryKind::Runtime.into())
+}
+
+fn alloc_env_var_as_wide_str<'mir, 'tcx>(
+    name: &OsStr,
+    value: &OsStr,
+    ecx: &mut InterpCx<'mir, 'tcx, MiriMachine<'mir, 'tcx>>,
+) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+    let mut name_osstring = name.to_os_string();
+    name_osstring.push("=");
+    name_osstring.push(value);
+    ecx.alloc_os_str_as_wide_str(name_osstring.as_os_str(), MiriMemoryKind::Runtime.into())
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn getenv(
+        &mut self,
+        name_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("getenv");
+
+        let name_ptr = this.read_pointer(name_op)?;
+        let name = this.read_os_str_from_c_str(name_ptr)?;
+        Ok(match this.machine.env_vars.map.get(name) {
+            Some(var_ptr) => {
+                // The offset is used to strip the "{name}=" part of the string.
+                var_ptr.offset(
+                    Size::from_bytes(u64::try_from(name.len()).unwrap().checked_add(1).unwrap()),
+                    this,
+                )?
+            }
+            None => Pointer::null(),
+        })
+    }
+
+    #[allow(non_snake_case)]
+    fn GetEnvironmentVariableW(
+        &mut self,
+        name_op: &OpTy<'tcx, Provenance>, // LPCWSTR
+        buf_op: &OpTy<'tcx, Provenance>,  // LPWSTR
+        size_op: &OpTy<'tcx, Provenance>, // DWORD
+    ) -> InterpResult<'tcx, u32> {
+        // ^ Returns DWORD (u32 on Windows)
+
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "GetEnvironmentVariableW");
+
+        let name_ptr = this.read_pointer(name_op)?;
+        let name = this.read_os_str_from_wide_str(name_ptr)?;
+        Ok(match this.machine.env_vars.map.get(&name) {
+            Some(var_ptr) => {
+                // The offset is used to strip the "{name}=" part of the string.
+                #[rustfmt::skip]
+                let name_offset_bytes = u64::try_from(name.len()).unwrap()
+                    .checked_add(1).unwrap()
+                    .checked_mul(2).unwrap();
+                let var_ptr = var_ptr.offset(Size::from_bytes(name_offset_bytes), this)?;
+                let var = this.read_os_str_from_wide_str(var_ptr)?;
+
+                let buf_ptr = this.read_pointer(buf_op)?;
+                // `buf_size` represents the size in characters.
+                let buf_size = u64::from(this.read_scalar(size_op)?.to_u32()?);
+                windows_check_buffer_size(this.write_os_str_to_wide_str(&var, buf_ptr, buf_size)?)
+            }
+            None => {
+                let envvar_not_found = this.eval_windows("c", "ERROR_ENVVAR_NOT_FOUND")?;
+                this.set_last_error(envvar_not_found)?;
+                0 // return zero upon failure
+            }
+        })
+    }
+
+    #[allow(non_snake_case)]
+    fn GetEnvironmentStringsW(&mut self) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "GetEnvironmentStringsW");
+
+        // Info on layout of environment blocks in Windows:
+        // https://docs.microsoft.com/en-us/windows/win32/procthread/environment-variables
+        let mut env_vars = std::ffi::OsString::new();
+        for &item in this.machine.env_vars.map.values() {
+            let env_var = this.read_os_str_from_wide_str(item)?;
+            env_vars.push(env_var);
+            env_vars.push("\0");
+        }
+        // Allocate environment block & Store environment variables to environment block.
+        // Final null terminator(block terminator) is added by `alloc_os_str_to_wide_str`.
+        let envblock_ptr =
+            this.alloc_os_str_as_wide_str(&env_vars, MiriMemoryKind::Runtime.into())?;
+        // If the function succeeds, the return value is a pointer to the environment block of the current process.
+        Ok(envblock_ptr)
+    }
+
+    #[allow(non_snake_case)]
+    fn FreeEnvironmentStringsW(
+        &mut self,
+        env_block_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "FreeEnvironmentStringsW");
+
+        let env_block_ptr = this.read_pointer(env_block_op)?;
+        let result = this.deallocate_ptr(env_block_ptr, None, MiriMemoryKind::Runtime.into());
+        // If the function succeeds, the return value is nonzero.
+        Ok(i32::from(result.is_ok()))
+    }
+
+    fn setenv(
+        &mut self,
+        name_op: &OpTy<'tcx, Provenance>,
+        value_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("setenv");
+
+        let name_ptr = this.read_pointer(name_op)?;
+        let value_ptr = this.read_pointer(value_op)?;
+
+        let mut new = None;
+        if !this.ptr_is_null(name_ptr)? {
+            let name = this.read_os_str_from_c_str(name_ptr)?;
+            if !name.is_empty() && !name.to_string_lossy().contains('=') {
+                let value = this.read_os_str_from_c_str(value_ptr)?;
+                new = Some((name.to_owned(), value.to_owned()));
+            }
+        }
+        if let Some((name, value)) = new {
+            let var_ptr = alloc_env_var_as_c_str(&name, &value, this)?;
+            if let Some(var) = this.machine.env_vars.map.insert(name, var_ptr) {
+                this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
+            }
+            this.update_environ()?;
+            Ok(0) // return zero on success
+        } else {
+            // name argument is a null pointer, points to an empty string, or points to a string containing an '=' character.
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            Ok(-1)
+        }
+    }
+
+    #[allow(non_snake_case)]
+    fn SetEnvironmentVariableW(
+        &mut self,
+        name_op: &OpTy<'tcx, Provenance>,  // LPCWSTR
+        value_op: &OpTy<'tcx, Provenance>, // LPCWSTR
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "SetEnvironmentVariableW");
+
+        let name_ptr = this.read_pointer(name_op)?;
+        let value_ptr = this.read_pointer(value_op)?;
+
+        if this.ptr_is_null(name_ptr)? {
+            // ERROR CODE is not clearly explained in docs.. For now, throw UB instead.
+            throw_ub_format!("pointer to environment variable name is NULL");
+        }
+
+        let name = this.read_os_str_from_wide_str(name_ptr)?;
+        if name.is_empty() {
+            throw_unsup_format!("environment variable name is an empty string");
+        } else if name.to_string_lossy().contains('=') {
+            throw_unsup_format!("environment variable name contains '='");
+        } else if this.ptr_is_null(value_ptr)? {
+            // Delete environment variable `{name}`
+            if let Some(var) = this.machine.env_vars.map.remove(&name) {
+                this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
+                this.update_environ()?;
+            }
+            Ok(1) // return non-zero on success
+        } else {
+            let value = this.read_os_str_from_wide_str(value_ptr)?;
+            let var_ptr = alloc_env_var_as_wide_str(&name, &value, this)?;
+            if let Some(var) = this.machine.env_vars.map.insert(name, var_ptr) {
+                this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
+            }
+            this.update_environ()?;
+            Ok(1) // return non-zero on success
+        }
+    }
+
+    fn unsetenv(&mut self, name_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("unsetenv");
+
+        let name_ptr = this.read_pointer(name_op)?;
+        let mut success = None;
+        if !this.ptr_is_null(name_ptr)? {
+            let name = this.read_os_str_from_c_str(name_ptr)?.to_owned();
+            if !name.is_empty() && !name.to_string_lossy().contains('=') {
+                success = Some(this.machine.env_vars.map.remove(&name));
+            }
+        }
+        if let Some(old) = success {
+            if let Some(var) = old {
+                this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
+            }
+            this.update_environ()?;
+            Ok(0)
+        } else {
+            // name argument is a null pointer, points to an empty string, or points to a string containing an '=' character.
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            Ok(-1)
+        }
+    }
+
+    fn getcwd(
+        &mut self,
+        buf_op: &OpTy<'tcx, Provenance>,
+        size_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("getcwd");
+
+        let buf = this.read_pointer(buf_op)?;
+        let size = this.read_scalar(size_op)?.to_machine_usize(&*this.tcx)?;
+
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`getcwd`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(Pointer::null());
+        }
+
+        // If we cannot get the current directory, we return null
+        match env::current_dir() {
+            Ok(cwd) => {
+                if this.write_path_to_c_str(&cwd, buf, size)?.0 {
+                    return Ok(buf);
+                }
+                let erange = this.eval_libc("ERANGE")?;
+                this.set_last_error(erange)?;
+            }
+            Err(e) => this.set_last_error_from_io_error(e.kind())?,
+        }
+
+        Ok(Pointer::null())
+    }
+
+    #[allow(non_snake_case)]
+    fn GetCurrentDirectoryW(
+        &mut self,
+        size_op: &OpTy<'tcx, Provenance>, // DWORD
+        buf_op: &OpTy<'tcx, Provenance>,  // LPTSTR
+    ) -> InterpResult<'tcx, u32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "GetCurrentDirectoryW");
+
+        let size = u64::from(this.read_scalar(size_op)?.to_u32()?);
+        let buf = this.read_pointer(buf_op)?;
+
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`GetCurrentDirectoryW`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(0);
+        }
+
+        // If we cannot get the current directory, we return 0
+        match env::current_dir() {
+            Ok(cwd) =>
+                return Ok(windows_check_buffer_size(this.write_path_to_wide_str(&cwd, buf, size)?)),
+            Err(e) => this.set_last_error_from_io_error(e.kind())?,
+        }
+        Ok(0)
+    }
+
+    fn chdir(&mut self, path_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("chdir");
+
+        let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;
+
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`chdir`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+
+            return Ok(-1);
+        }
+
+        match env::set_current_dir(path) {
+            Ok(()) => Ok(0),
+            Err(e) => {
+                this.set_last_error_from_io_error(e.kind())?;
+                Ok(-1)
+            }
+        }
+    }
+
+    #[allow(non_snake_case)]
+    fn SetCurrentDirectoryW(
+        &mut self,
+        path_op: &OpTy<'tcx, Provenance>, // LPCTSTR
+    ) -> InterpResult<'tcx, i32> {
+        // ^ Returns BOOL (i32 on Windows)
+
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "SetCurrentDirectoryW");
+
+        let path = this.read_path_from_wide_str(this.read_pointer(path_op)?)?;
+
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`SetCurrentDirectoryW`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+
+            return Ok(0);
+        }
+
+        match env::set_current_dir(path) {
+            Ok(()) => Ok(1),
+            Err(e) => {
+                this.set_last_error_from_io_error(e.kind())?;
+                Ok(0)
+            }
+        }
+    }
+
+    /// Updates the `environ` static.
+    /// The first time it gets called, also initializes `extra.environ`.
+    fn update_environ(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        // Deallocate the old environ list, if any.
+        if let Some(environ) = this.machine.env_vars.environ {
+            let old_vars_ptr = this.read_pointer(&environ.into())?;
+            this.deallocate_ptr(old_vars_ptr, None, MiriMemoryKind::Runtime.into())?;
+        } else {
+            // No `environ` allocated yet, let's do that.
+            // This is memory backing an extern static, hence `ExternStatic`, not `Env`.
+            let layout = this.machine.layouts.mut_raw_ptr;
+            let place = this.allocate(layout, MiriMemoryKind::ExternStatic.into())?;
+            this.machine.env_vars.environ = Some(place);
+        }
+
+        // Collect all the pointers to each variable in a vector.
+        let mut vars: Vec<Pointer<Option<Provenance>>> =
+            this.machine.env_vars.map.values().copied().collect();
+        // Add the trailing null pointer.
+        vars.push(Pointer::null());
+        // Make an array with all these pointers inside Miri.
+        let tcx = this.tcx;
+        let vars_layout = this.layout_of(
+            tcx.mk_array(this.machine.layouts.mut_raw_ptr.ty, u64::try_from(vars.len()).unwrap()),
+        )?;
+        let vars_place = this.allocate(vars_layout, MiriMemoryKind::Runtime.into())?;
+        for (idx, var) in vars.into_iter().enumerate() {
+            let place = this.mplace_field(&vars_place, idx)?;
+            this.write_pointer(var, &place.into())?;
+        }
+        this.write_pointer(vars_place.ptr, &this.machine.env_vars.environ.unwrap().into())?;
+
+        Ok(())
+    }
+
+    fn getpid(&mut self) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("getpid");
+
+        this.check_no_isolation("`getpid`")?;
+
+        // The reason we need to do this wacky of a conversion is because
+        // `libc::getpid` returns an i32, however, `std::process::id()` return an u32.
+        // So we un-do the conversion that stdlib does and turn it back into an i32.
+        #[allow(clippy::cast_possible_wrap)]
+        Ok(std::process::id() as i32)
+    }
+
+    #[allow(non_snake_case)]
+    fn GetCurrentProcessId(&mut self) -> InterpResult<'tcx, u32> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("windows", "GetCurrentProcessId");
+
+        this.check_no_isolation("`GetCurrentProcessId`")?;
+
+        Ok(std::process::id())
+    }
+}
diff --git a/src/tools/miri/src/shims/ffi_support.rs b/src/tools/miri/src/shims/ffi_support.rs
new file mode 100644
index 000000000000..0813554e9d24
--- /dev/null
+++ b/src/tools/miri/src/shims/ffi_support.rs
@@ -0,0 +1,291 @@
+use libffi::{high::call as ffi, low::CodePtr};
+use std::ops::Deref;
+
+use rustc_middle::ty::{self as ty, IntTy, Ty, UintTy};
+use rustc_span::Symbol;
+use rustc_target::abi::HasDataLayout;
+
+use crate::*;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Extract the scalar value from the result of reading a scalar from the machine,
+    /// and convert it to a `CArg`.
+    fn scalar_to_carg(
+        k: Scalar<Provenance>,
+        arg_type: Ty<'tcx>,
+        cx: &impl HasDataLayout,
+    ) -> InterpResult<'tcx, CArg> {
+        match arg_type.kind() {
+            // If the primitive provided can be converted to a type matching the type pattern
+            // then create a `CArg` of this primitive value with the corresponding `CArg` constructor.
+            // the ints
+            ty::Int(IntTy::I8) => {
+                return Ok(CArg::Int8(k.to_i8()?));
+            }
+            ty::Int(IntTy::I16) => {
+                return Ok(CArg::Int16(k.to_i16()?));
+            }
+            ty::Int(IntTy::I32) => {
+                return Ok(CArg::Int32(k.to_i32()?));
+            }
+            ty::Int(IntTy::I64) => {
+                return Ok(CArg::Int64(k.to_i64()?));
+            }
+            ty::Int(IntTy::Isize) => {
+                // This will fail if host != target, but then the entire FFI thing probably won't work well
+                // in that situation.
+                return Ok(CArg::ISize(k.to_machine_isize(cx)?.try_into().unwrap()));
+            }
+            // the uints
+            ty::Uint(UintTy::U8) => {
+                return Ok(CArg::UInt8(k.to_u8()?));
+            }
+            ty::Uint(UintTy::U16) => {
+                return Ok(CArg::UInt16(k.to_u16()?));
+            }
+            ty::Uint(UintTy::U32) => {
+                return Ok(CArg::UInt32(k.to_u32()?));
+            }
+            ty::Uint(UintTy::U64) => {
+                return Ok(CArg::UInt64(k.to_u64()?));
+            }
+            ty::Uint(UintTy::Usize) => {
+                // This will fail if host != target, but then the entire FFI thing probably won't work well
+                // in that situation.
+                return Ok(CArg::USize(k.to_machine_usize(cx)?.try_into().unwrap()));
+            }
+            _ => {}
+        }
+        // If no primitives were returned then we have an unsupported type.
+        throw_unsup_format!(
+            "unsupported scalar argument type to external C function: {:?}",
+            arg_type
+        );
+    }
+
+    /// Call external C function and
+    /// store output, depending on return type in the function signature.
+    fn call_external_c_and_store_return<'a>(
+        &mut self,
+        link_name: Symbol,
+        dest: &PlaceTy<'tcx, Provenance>,
+        ptr: CodePtr,
+        libffi_args: Vec<libffi::high::Arg<'a>>,
+    ) -> InterpResult<'tcx, ()> {
+        let this = self.eval_context_mut();
+
+        // Unsafe because of the call to external C code.
+        // Because this is calling a C function it is not necessarily sound,
+        // but there is no way around this and we've checked as much as we can.
+        unsafe {
+            // If the return type of a function is a primitive integer type,
+            // then call the function (`ptr`) with arguments `libffi_args`, store the return value as the specified
+            // primitive integer type, and then write this value out to the miri memory as an integer.
+            match dest.layout.ty.kind() {
+                // ints
+                ty::Int(IntTy::I8) => {
+                    let x = ffi::call::<i8>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Int(IntTy::I16) => {
+                    let x = ffi::call::<i16>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Int(IntTy::I32) => {
+                    let x = ffi::call::<i32>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Int(IntTy::I64) => {
+                    let x = ffi::call::<i64>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Int(IntTy::Isize) => {
+                    let x = ffi::call::<isize>(ptr, libffi_args.as_slice());
+                    // `isize` doesn't `impl Into<i128>`, so convert manually.
+                    // Convert to `i64` since this covers both 32- and 64-bit machines.
+                    this.write_int(i64::try_from(x).unwrap(), dest)?;
+                    return Ok(());
+                }
+                // uints
+                ty::Uint(UintTy::U8) => {
+                    let x = ffi::call::<u8>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Uint(UintTy::U16) => {
+                    let x = ffi::call::<u16>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Uint(UintTy::U32) => {
+                    let x = ffi::call::<u32>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Uint(UintTy::U64) => {
+                    let x = ffi::call::<u64>(ptr, libffi_args.as_slice());
+                    this.write_int(x, dest)?;
+                    return Ok(());
+                }
+                ty::Uint(UintTy::Usize) => {
+                    let x = ffi::call::<usize>(ptr, libffi_args.as_slice());
+                    // `usize` doesn't `impl Into<i128>`, so convert manually.
+                    // Convert to `u64` since this covers both 32- and 64-bit machines.
+                    this.write_int(u64::try_from(x).unwrap(), dest)?;
+                    return Ok(());
+                }
+                // Functions with no declared return type (i.e., the default return)
+                // have the output_type `Tuple([])`.
+                ty::Tuple(t_list) =>
+                    if t_list.len() == 0 {
+                        ffi::call::<()>(ptr, libffi_args.as_slice());
+                        return Ok(());
+                    },
+                _ => {}
+            }
+            // FIXME ellen! deal with all the other return types
+            throw_unsup_format!("unsupported return type to external C function: {:?}", link_name);
+        }
+    }
+
+    /// Get the pointer to the function of the specified name in the shared object file,
+    /// if it exists. The function must be in the shared object file specified: we do *not*
+    /// return pointers to functions in dependencies of the library.  
+    fn get_func_ptr_explicitly_from_lib(&mut self, link_name: Symbol) -> Option<CodePtr> {
+        let this = self.eval_context_mut();
+        // Try getting the function from the shared library.
+        // On windows `_lib_path` will be unused, hence the name starting with `_`.
+        let (lib, _lib_path) = this.machine.external_so_lib.as_ref().unwrap();
+        let func: libloading::Symbol<'_, unsafe extern "C" fn()> = unsafe {
+            match lib.get(link_name.as_str().as_bytes()) {
+                Ok(x) => x,
+                Err(_) => {
+                    return None;
+                }
+            }
+        };
+
+        // FIXME: this is a hack!
+        // The `libloading` crate will automatically load system libraries like `libc`.
+        // On linux `libloading` is based on `dlsym`: https://docs.rs/libloading/0.7.3/src/libloading/os/unix/mod.rs.html#202
+        // and `dlsym`(https://linux.die.net/man/3/dlsym) looks through the dependency tree of the
+        // library if it can't find the symbol in the library itself.
+        // So, in order to check if the function was actually found in the specified
+        // `machine.external_so_lib` we need to check its `dli_fname` and compare it to
+        // the specified SO file path.
+        // This code is a reimplementation of the mechanism for getting `dli_fname` in `libloading`,
+        // from: https://docs.rs/libloading/0.7.3/src/libloading/os/unix/mod.rs.html#411
+        // using the `libc` crate where this interface is public.
+        // No `libc::dladdr` on windows.
+        #[cfg(unix)]
+        let mut info = std::mem::MaybeUninit::<libc::Dl_info>::uninit();
+        #[cfg(unix)]
+        unsafe {
+            if libc::dladdr(*func.deref() as *const _, info.as_mut_ptr()) != 0 {
+                if std::ffi::CStr::from_ptr(info.assume_init().dli_fname).to_str().unwrap()
+                    != _lib_path.to_str().unwrap()
+                {
+                    return None;
+                }
+            }
+        }
+        // Return a pointer to the function.
+        Some(CodePtr(*func.deref() as *mut _))
+    }
+
+    /// Call specified external C function, with supplied arguments.
+    /// Need to convert all the arguments from their hir representations to
+    /// a form compatible with C (through `libffi` call).
+    /// Then, convert return from the C call into a corresponding form that
+    /// can be stored in Miri internal memory.
+    fn call_external_c_fct(
+        &mut self,
+        link_name: Symbol,
+        dest: &PlaceTy<'tcx, Provenance>,
+        args: &[OpTy<'tcx, Provenance>],
+    ) -> InterpResult<'tcx, bool> {
+        // Get the pointer to the function in the shared object file if it exists.
+        let code_ptr = match self.get_func_ptr_explicitly_from_lib(link_name) {
+            Some(ptr) => ptr,
+            None => {
+                // Shared object file does not export this function -- try the shims next.
+                return Ok(false);
+            }
+        };
+
+        let this = self.eval_context_mut();
+
+        // Get the function arguments, and convert them to `libffi`-compatible form.
+        let mut libffi_args = Vec::<CArg>::with_capacity(args.len());
+        for cur_arg in args.iter() {
+            libffi_args.push(Self::scalar_to_carg(
+                this.read_scalar(cur_arg)?,
+                cur_arg.layout.ty,
+                this,
+            )?);
+        }
+
+        // Convert them to `libffi::high::Arg` type.
+        let libffi_args = libffi_args
+            .iter()
+            .map(|cur_arg| cur_arg.arg_downcast())
+            .collect::<Vec<libffi::high::Arg<'_>>>();
+
+        // Call the function and store output, depending on return type in the function signature.
+        self.call_external_c_and_store_return(link_name, dest, code_ptr, libffi_args)?;
+        Ok(true)
+    }
+}
+
+#[derive(Debug, Clone)]
+/// Enum of supported arguments to external C functions.
+// We introduce this enum instead of just calling `ffi::arg` and storing a list
+// of `libffi::high::Arg` directly, because the `libffi::high::Arg` just wraps a reference
+// to the value it represents: https://docs.rs/libffi/latest/libffi/high/call/struct.Arg.html
+// and we need to store a copy of the value, and pass a reference to this copy to C instead.
+pub enum CArg {
+    /// 8-bit signed integer.
+    Int8(i8),
+    /// 16-bit signed integer.
+    Int16(i16),
+    /// 32-bit signed integer.
+    Int32(i32),
+    /// 64-bit signed integer.
+    Int64(i64),
+    /// isize.
+    ISize(isize),
+    /// 8-bit unsigned integer.
+    UInt8(u8),
+    /// 16-bit unsigned integer.
+    UInt16(u16),
+    /// 32-bit unsigned integer.
+    UInt32(u32),
+    /// 64-bit unsigned integer.
+    UInt64(u64),
+    /// usize.
+    USize(usize),
+}
+
+impl<'a> CArg {
+    /// Convert a `CArg` to a `libffi` argument type.
+    fn arg_downcast(&'a self) -> libffi::high::Arg<'a> {
+        match self {
+            CArg::Int8(i) => ffi::arg(i),
+            CArg::Int16(i) => ffi::arg(i),
+            CArg::Int32(i) => ffi::arg(i),
+            CArg::Int64(i) => ffi::arg(i),
+            CArg::ISize(i) => ffi::arg(i),
+            CArg::UInt8(i) => ffi::arg(i),
+            CArg::UInt16(i) => ffi::arg(i),
+            CArg::UInt32(i) => ffi::arg(i),
+            CArg::UInt64(i) => ffi::arg(i),
+            CArg::USize(i) => ffi::arg(i),
+        }
+    }
+}
diff --git a/src/tools/miri/src/shims/foreign_items.rs b/src/tools/miri/src/shims/foreign_items.rs
new file mode 100644
index 000000000000..bb62a2a7ec1b
--- /dev/null
+++ b/src/tools/miri/src/shims/foreign_items.rs
@@ -0,0 +1,811 @@
+use std::{collections::hash_map::Entry, iter};
+
+use log::trace;
+
+use rustc_apfloat::Float;
+use rustc_ast::expand::allocator::AllocatorKind;
+use rustc_hir::{
+    def::DefKind,
+    def_id::{CrateNum, DefId, LOCAL_CRATE},
+};
+use rustc_middle::middle::{
+    codegen_fn_attrs::CodegenFnAttrFlags, dependency_format::Linkage,
+    exported_symbols::ExportedSymbol,
+};
+use rustc_middle::mir;
+use rustc_middle::ty;
+use rustc_session::config::CrateType;
+use rustc_span::Symbol;
+use rustc_target::{
+    abi::{Align, Size},
+    spec::abi::Abi,
+};
+
+use super::backtrace::EvalContextExt as _;
+use crate::helpers::{convert::Truncate, target_os_is_unix};
+#[cfg(unix)]
+use crate::shims::ffi_support::EvalContextExt as _;
+use crate::*;
+
+/// Returned by `emulate_foreign_item_by_name`.
+pub enum EmulateByNameResult<'mir, 'tcx> {
+    /// The caller is expected to jump to the return block.
+    NeedsJumping,
+    /// Jumping has already been taken care of.
+    AlreadyJumped,
+    /// A MIR body has been found for the function.
+    MirBody(&'mir mir::Body<'tcx>, ty::Instance<'tcx>),
+    /// The item is not supported.
+    NotSupported,
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Returns the minimum alignment for the target architecture for allocations of the given size.
+    fn min_align(&self, size: u64, kind: MiriMemoryKind) -> Align {
+        let this = self.eval_context_ref();
+        // List taken from `library/std/src/sys/common/alloc.rs`.
+        // This list should be kept in sync with the one from libstd.
+        let min_align = match this.tcx.sess.target.arch.as_ref() {
+            "x86" | "arm" | "mips" | "powerpc" | "powerpc64" | "asmjs" | "wasm32" => 8,
+            "x86_64" | "aarch64" | "mips64" | "s390x" | "sparc64" => 16,
+            arch => bug!("Unsupported target architecture: {}", arch),
+        };
+        // Windows always aligns, even small allocations.
+        // Source: <https://support.microsoft.com/en-us/help/286470/how-to-use-pageheap-exe-in-windows-xp-windows-2000-and-windows-server>
+        // But jemalloc does not, so for the C heap we only align if the allocation is sufficiently big.
+        if kind == MiriMemoryKind::WinHeap || size >= min_align {
+            return Align::from_bytes(min_align).unwrap();
+        }
+        // We have `size < min_align`. Round `size` *down* to the next power of two and use that.
+        fn prev_power_of_two(x: u64) -> u64 {
+            let next_pow2 = x.next_power_of_two();
+            if next_pow2 == x {
+                // x *is* a power of two, just use that.
+                x
+            } else {
+                // x is between two powers, so next = 2*prev.
+                next_pow2 / 2
+            }
+        }
+        Align::from_bytes(prev_power_of_two(size)).unwrap()
+    }
+
+    fn malloc(
+        &mut self,
+        size: u64,
+        zero_init: bool,
+        kind: MiriMemoryKind,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let this = self.eval_context_mut();
+        if size == 0 {
+            Ok(Pointer::null())
+        } else {
+            let align = this.min_align(size, kind);
+            let ptr = this.allocate_ptr(Size::from_bytes(size), align, kind.into())?;
+            if zero_init {
+                // We just allocated this, the access is definitely in-bounds and fits into our address space.
+                this.write_bytes_ptr(
+                    ptr.into(),
+                    iter::repeat(0u8).take(usize::try_from(size).unwrap()),
+                )
+                .unwrap();
+            }
+            Ok(ptr.into())
+        }
+    }
+
+    fn free(
+        &mut self,
+        ptr: Pointer<Option<Provenance>>,
+        kind: MiriMemoryKind,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        if !this.ptr_is_null(ptr)? {
+            this.deallocate_ptr(ptr, None, kind.into())?;
+        }
+        Ok(())
+    }
+
+    fn realloc(
+        &mut self,
+        old_ptr: Pointer<Option<Provenance>>,
+        new_size: u64,
+        kind: MiriMemoryKind,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let this = self.eval_context_mut();
+        let new_align = this.min_align(new_size, kind);
+        if this.ptr_is_null(old_ptr)? {
+            if new_size == 0 {
+                Ok(Pointer::null())
+            } else {
+                let new_ptr =
+                    this.allocate_ptr(Size::from_bytes(new_size), new_align, kind.into())?;
+                Ok(new_ptr.into())
+            }
+        } else {
+            if new_size == 0 {
+                this.deallocate_ptr(old_ptr, None, kind.into())?;
+                Ok(Pointer::null())
+            } else {
+                let new_ptr = this.reallocate_ptr(
+                    old_ptr,
+                    None,
+                    Size::from_bytes(new_size),
+                    new_align,
+                    kind.into(),
+                )?;
+                Ok(new_ptr.into())
+            }
+        }
+    }
+
+    /// Lookup the body of a function that has `link_name` as the symbol name.
+    fn lookup_exported_symbol(
+        &mut self,
+        link_name: Symbol,
+    ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
+        let this = self.eval_context_mut();
+        let tcx = this.tcx.tcx;
+
+        // If the result was cached, just return it.
+        // (Cannot use `or_insert` since the code below might have to throw an error.)
+        let entry = this.machine.exported_symbols_cache.entry(link_name);
+        let instance = *match entry {
+            Entry::Occupied(e) => e.into_mut(),
+            Entry::Vacant(e) => {
+                // Find it if it was not cached.
+                let mut instance_and_crate: Option<(ty::Instance<'_>, CrateNum)> = None;
+                // `dependency_formats` includes all the transitive informations needed to link a crate,
+                // which is what we need here since we need to dig out `exported_symbols` from all transitive
+                // dependencies.
+                let dependency_formats = tcx.dependency_formats(());
+                let dependency_format = dependency_formats
+                    .iter()
+                    .find(|(crate_type, _)| *crate_type == CrateType::Executable)
+                    .expect("interpreting a non-executable crate");
+                for cnum in iter::once(LOCAL_CRATE).chain(
+                    dependency_format.1.iter().enumerate().filter_map(|(num, &linkage)| {
+                        // We add 1 to the number because that's what rustc also does everywhere it
+                        // calls `CrateNum::new`...
+                        #[allow(clippy::integer_arithmetic)]
+                        (linkage != Linkage::NotLinked).then_some(CrateNum::new(num + 1))
+                    }),
+                ) {
+                    // We can ignore `_export_info` here: we are a Rust crate, and everything is exported
+                    // from a Rust crate.
+                    for &(symbol, _export_info) in tcx.exported_symbols(cnum) {
+                        if let ExportedSymbol::NonGeneric(def_id) = symbol {
+                            let attrs = tcx.codegen_fn_attrs(def_id);
+                            let symbol_name = if let Some(export_name) = attrs.export_name {
+                                export_name
+                            } else if attrs.flags.contains(CodegenFnAttrFlags::NO_MANGLE) {
+                                tcx.item_name(def_id)
+                            } else {
+                                // Skip over items without an explicitly defined symbol name.
+                                continue;
+                            };
+                            if symbol_name == link_name {
+                                if let Some((original_instance, original_cnum)) = instance_and_crate
+                                {
+                                    // Make sure we are consistent wrt what is 'first' and 'second'.
+                                    let original_span =
+                                        tcx.def_span(original_instance.def_id()).data();
+                                    let span = tcx.def_span(def_id).data();
+                                    if original_span < span {
+                                        throw_machine_stop!(
+                                            TerminationInfo::MultipleSymbolDefinitions {
+                                                link_name,
+                                                first: original_span,
+                                                first_crate: tcx.crate_name(original_cnum),
+                                                second: span,
+                                                second_crate: tcx.crate_name(cnum),
+                                            }
+                                        );
+                                    } else {
+                                        throw_machine_stop!(
+                                            TerminationInfo::MultipleSymbolDefinitions {
+                                                link_name,
+                                                first: span,
+                                                first_crate: tcx.crate_name(cnum),
+                                                second: original_span,
+                                                second_crate: tcx.crate_name(original_cnum),
+                                            }
+                                        );
+                                    }
+                                }
+                                if !matches!(tcx.def_kind(def_id), DefKind::Fn | DefKind::AssocFn) {
+                                    throw_ub_format!(
+                                        "attempt to call an exported symbol that is not defined as a function"
+                                    );
+                                }
+                                instance_and_crate = Some((ty::Instance::mono(tcx, def_id), cnum));
+                            }
+                        }
+                    }
+                }
+
+                e.insert(instance_and_crate.map(|ic| ic.0))
+            }
+        };
+        match instance {
+            None => Ok(None), // no symbol with this name
+            Some(instance) => Ok(Some((this.load_mir(instance.def, None)?, instance))),
+        }
+    }
+
+    /// Emulates calling a foreign item, failing if the item is not supported.
+    /// This function will handle `goto_block` if needed.
+    /// Returns Ok(None) if the foreign item was completely handled
+    /// by this function.
+    /// Returns Ok(Some(body)) if processing the foreign item
+    /// is delegated to another function.
+    fn emulate_foreign_item(
+        &mut self,
+        def_id: DefId,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
+        let this = self.eval_context_mut();
+        let link_name = this.item_link_name(def_id);
+        let tcx = this.tcx.tcx;
+
+        // First: functions that diverge.
+        let ret = match ret {
+            None =>
+                match link_name.as_str() {
+                    "miri_start_panic" => {
+                        // `check_shim` happens inside `handle_miri_start_panic`.
+                        this.handle_miri_start_panic(abi, link_name, args, unwind)?;
+                        return Ok(None);
+                    }
+                    // This matches calls to the foreign item `panic_impl`.
+                    // The implementation is provided by the function with the `#[panic_handler]` attribute.
+                    "panic_impl" => {
+                        // We don't use `check_shim` here because we are just forwarding to the lang
+                        // item. Argument count checking will be performed when the returned `Body` is
+                        // called.
+                        this.check_abi_and_shim_symbol_clash(abi, Abi::Rust, link_name)?;
+                        let panic_impl_id = tcx.lang_items().panic_impl().unwrap();
+                        let panic_impl_instance = ty::Instance::mono(tcx, panic_impl_id);
+                        return Ok(Some((
+                            this.load_mir(panic_impl_instance.def, None)?,
+                            panic_impl_instance,
+                        )));
+                    }
+                    #[rustfmt::skip]
+                    | "exit"
+                    | "ExitProcess"
+                    => {
+                        let exp_abi = if link_name.as_str() == "exit" {
+                            Abi::C { unwind: false }
+                        } else {
+                            Abi::System { unwind: false }
+                        };
+                        let [code] = this.check_shim(abi, exp_abi, link_name, args)?;
+                        // it's really u32 for ExitProcess, but we have to put it into the `Exit` variant anyway
+                        let code = this.read_scalar(code)?.to_i32()?;
+                        throw_machine_stop!(TerminationInfo::Exit(code.into()));
+                    }
+                    "abort" => {
+                        let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                        throw_machine_stop!(TerminationInfo::Abort(
+                            "the program aborted execution".to_owned()
+                        ))
+                    }
+                    _ => {
+                        if let Some(body) = this.lookup_exported_symbol(link_name)? {
+                            return Ok(Some(body));
+                        }
+                        this.handle_unsupported(format!(
+                            "can't call (diverging) foreign function: {}",
+                            link_name
+                        ))?;
+                        return Ok(None);
+                    }
+                },
+            Some(p) => p,
+        };
+
+        // Second: functions that return immediately.
+        match this.emulate_foreign_item_by_name(link_name, abi, args, dest)? {
+            EmulateByNameResult::NeedsJumping => {
+                trace!("{:?}", this.dump_place(**dest));
+                this.go_to_block(ret);
+            }
+            EmulateByNameResult::AlreadyJumped => (),
+            EmulateByNameResult::MirBody(mir, instance) => return Ok(Some((mir, instance))),
+            EmulateByNameResult::NotSupported => {
+                if let Some(body) = this.lookup_exported_symbol(link_name)? {
+                    return Ok(Some(body));
+                }
+
+                this.handle_unsupported(format!("can't call foreign function: {}", link_name))?;
+                return Ok(None);
+            }
+        }
+
+        Ok(None)
+    }
+
+    /// Emulates calling the internal __rust_* allocator functions
+    fn emulate_allocator(
+        &mut self,
+        symbol: Symbol,
+        default: impl FnOnce(&mut MiriInterpCx<'mir, 'tcx>) -> InterpResult<'tcx>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+
+        let allocator_kind = if let Some(allocator_kind) = this.tcx.allocator_kind(()) {
+            allocator_kind
+        } else {
+            // in real code, this symbol does not exist without an allocator
+            return Ok(EmulateByNameResult::NotSupported);
+        };
+
+        match allocator_kind {
+            AllocatorKind::Global => {
+                let (body, instance) = this
+                    .lookup_exported_symbol(symbol)?
+                    .expect("symbol should be present if there is a global allocator");
+
+                Ok(EmulateByNameResult::MirBody(body, instance))
+            }
+            AllocatorKind::Default => {
+                default(this)?;
+                Ok(EmulateByNameResult::NeedsJumping)
+            }
+        }
+    }
+
+    /// Emulates calling a foreign item using its name.
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+
+        // First deal with any external C functions in linked .so file.
+        #[cfg(unix)]
+        if this.machine.external_so_lib.as_ref().is_some() {
+            // An Ok(false) here means that the function being called was not exported
+            // by the specified `.so` file; we should continue and check if it corresponds to
+            // a provided shim.
+            if this.call_external_c_fct(link_name, dest, args)? {
+                return Ok(EmulateByNameResult::NeedsJumping);
+            }
+        }
+
+        // When adding a new shim, you should follow the following pattern:
+        // ```
+        // "shim_name" => {
+        //     let [arg1, arg2, arg3] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+        //     let result = this.shim_name(arg1, arg2, arg3)?;
+        //     this.write_scalar(result, dest)?;
+        // }
+        // ```
+        // and then define `shim_name` as a helper function in an extension trait in a suitable file
+        // (see e.g. `unix/fs.rs`):
+        // ```
+        // fn shim_name(
+        //     &mut self,
+        //     arg1: &OpTy<'tcx, Provenance>,
+        //     arg2: &OpTy<'tcx, Provenance>,
+        //     arg3: &OpTy<'tcx, Provenance>)
+        // -> InterpResult<'tcx, Scalar<Provenance>> {
+        //     let this = self.eval_context_mut();
+        //
+        //     // First thing: load all the arguments. Details depend on the shim.
+        //     let arg1 = this.read_scalar(arg1)?.to_u32()?;
+        //     let arg2 = this.read_pointer(arg2)?; // when you need to work with the pointer directly
+        //     let arg3 = this.deref_operand(arg3)?; // when you want to load/store through the pointer at its declared type
+        //
+        //     // ...
+        //
+        //     Ok(Scalar::from_u32(42))
+        // }
+        // ```
+        // You might find existing shims not following this pattern, most
+        // likely because they predate it or because for some reason they cannot be made to fit.
+
+        // Here we dispatch all the shims for foreign functions. If you have a platform specific
+        // shim, add it to the corresponding submodule.
+        match link_name.as_str() {
+            // Miri-specific extern functions
+            "miri_static_root" => {
+                let [ptr] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let (alloc_id, offset, _) = this.ptr_get_alloc_id(ptr)?;
+                if offset != Size::ZERO {
+                    throw_unsup_format!("pointer passed to miri_static_root must point to beginning of an allocated block");
+                }
+                this.machine.static_roots.push(alloc_id);
+            }
+
+            // Obtains the size of a Miri backtrace. See the README for details.
+            "miri_backtrace_size" => {
+                this.handle_miri_backtrace_size(abi, link_name, args, dest)?;
+            }
+
+            // Obtains a Miri backtrace. See the README for details.
+            "miri_get_backtrace" => {
+                // `check_shim` happens inside `handle_miri_get_backtrace`.
+                this.handle_miri_get_backtrace(abi, link_name, args, dest)?;
+            }
+
+            // Resolves a Miri backtrace frame. See the README for details.
+            "miri_resolve_frame" => {
+                // `check_shim` happens inside `handle_miri_resolve_frame`.
+                this.handle_miri_resolve_frame(abi, link_name, args, dest)?;
+            }
+
+            // Writes the function and file names of a Miri backtrace frame into a user provided buffer. See the README for details.
+            "miri_resolve_frame_names" => {
+                this.handle_miri_resolve_frame_names(abi, link_name, args)?;
+            }
+
+            // Standard C allocation
+            "malloc" => {
+                let [size] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let size = this.read_scalar(size)?.to_machine_usize(this)?;
+                let res = this.malloc(size, /*zero_init:*/ false, MiriMemoryKind::C)?;
+                this.write_pointer(res, dest)?;
+            }
+            "calloc" => {
+                let [items, len] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let items = this.read_scalar(items)?.to_machine_usize(this)?;
+                let len = this.read_scalar(len)?.to_machine_usize(this)?;
+                let size =
+                    items.checked_mul(len).ok_or_else(|| err_ub_format!("overflow during calloc size computation"))?;
+                let res = this.malloc(size, /*zero_init:*/ true, MiriMemoryKind::C)?;
+                this.write_pointer(res, dest)?;
+            }
+            "free" => {
+                let [ptr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                this.free(ptr, MiriMemoryKind::C)?;
+            }
+            "realloc" => {
+                let [old_ptr, new_size] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let old_ptr = this.read_pointer(old_ptr)?;
+                let new_size = this.read_scalar(new_size)?.to_machine_usize(this)?;
+                let res = this.realloc(old_ptr, new_size, MiriMemoryKind::C)?;
+                this.write_pointer(res, dest)?;
+            }
+
+            // Rust allocation
+            "__rust_alloc" => {
+                let [size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+                let size = this.read_scalar(size)?.to_machine_usize(this)?;
+                let align = this.read_scalar(align)?.to_machine_usize(this)?;
+
+                return this.emulate_allocator(Symbol::intern("__rg_alloc"), |this| {
+                    Self::check_alloc_request(size, align)?;
+
+                    let ptr = this.allocate_ptr(
+                        Size::from_bytes(size),
+                        Align::from_bytes(align).unwrap(),
+                        MiriMemoryKind::Rust.into(),
+                    )?;
+
+                    this.write_pointer(ptr, dest)
+                });
+            }
+            "__rust_alloc_zeroed" => {
+                let [size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+                let size = this.read_scalar(size)?.to_machine_usize(this)?;
+                let align = this.read_scalar(align)?.to_machine_usize(this)?;
+
+                return this.emulate_allocator(Symbol::intern("__rg_alloc_zeroed"), |this| {
+                    Self::check_alloc_request(size, align)?;
+
+                    let ptr = this.allocate_ptr(
+                        Size::from_bytes(size),
+                        Align::from_bytes(align).unwrap(),
+                        MiriMemoryKind::Rust.into(),
+                    )?;
+
+                    // We just allocated this, the access is definitely in-bounds.
+                    this.write_bytes_ptr(ptr.into(), iter::repeat(0u8).take(usize::try_from(size).unwrap())).unwrap();
+                    this.write_pointer(ptr, dest)
+                });
+            }
+            "__rust_dealloc" => {
+                let [ptr, old_size, align] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let old_size = this.read_scalar(old_size)?.to_machine_usize(this)?;
+                let align = this.read_scalar(align)?.to_machine_usize(this)?;
+
+                return this.emulate_allocator(Symbol::intern("__rg_dealloc"), |this| {
+                    // No need to check old_size/align; we anyway check that they match the allocation.
+                    this.deallocate_ptr(
+                        ptr,
+                        Some((Size::from_bytes(old_size), Align::from_bytes(align).unwrap())),
+                        MiriMemoryKind::Rust.into(),
+                    )
+                });
+            }
+            "__rust_realloc" => {
+                let [ptr, old_size, align, new_size] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let old_size = this.read_scalar(old_size)?.to_machine_usize(this)?;
+                let align = this.read_scalar(align)?.to_machine_usize(this)?;
+                let new_size = this.read_scalar(new_size)?.to_machine_usize(this)?;
+                // No need to check old_size; we anyway check that they match the allocation.
+
+                return this.emulate_allocator(Symbol::intern("__rg_realloc"), |this| {
+                    Self::check_alloc_request(new_size, align)?;
+
+                    let align = Align::from_bytes(align).unwrap();
+                    let new_ptr = this.reallocate_ptr(
+                        ptr,
+                        Some((Size::from_bytes(old_size), align)),
+                        Size::from_bytes(new_size),
+                        align,
+                        MiriMemoryKind::Rust.into(),
+                    )?;
+                    this.write_pointer(new_ptr, dest)
+                });
+            }
+
+            // C memory handling functions
+            "memcmp" => {
+                let [left, right, n] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let left = this.read_pointer(left)?;
+                let right = this.read_pointer(right)?;
+                let n = Size::from_bytes(this.read_scalar(n)?.to_machine_usize(this)?);
+
+                let result = {
+                    let left_bytes = this.read_bytes_ptr_strip_provenance(left, n)?;
+                    let right_bytes = this.read_bytes_ptr_strip_provenance(right, n)?;
+
+                    use std::cmp::Ordering::*;
+                    match left_bytes.cmp(right_bytes) {
+                        Less => -1i32,
+                        Equal => 0,
+                        Greater => 1,
+                    }
+                };
+
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "memrchr" => {
+                let [ptr, val, num] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let val = this.read_scalar(val)?.to_i32()?;
+                let num = this.read_scalar(num)?.to_machine_usize(this)?;
+                // The docs say val is "interpreted as unsigned char".
+                #[allow(clippy::cast_sign_loss, clippy::cast_possible_truncation)]
+                let val = val as u8;
+
+                if let Some(idx) = this
+                    .read_bytes_ptr_strip_provenance(ptr, Size::from_bytes(num))?
+                    .iter()
+                    .rev()
+                    .position(|&c| c == val)
+                {
+                    let idx = u64::try_from(idx).unwrap();
+                    #[allow(clippy::integer_arithmetic)] // idx < num, so this never wraps
+                    let new_ptr = ptr.offset(Size::from_bytes(num - idx - 1), this)?;
+                    this.write_pointer(new_ptr, dest)?;
+                } else {
+                    this.write_null(dest)?;
+                }
+            }
+            "memchr" => {
+                let [ptr, val, num] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let val = this.read_scalar(val)?.to_i32()?;
+                let num = this.read_scalar(num)?.to_machine_usize(this)?;
+                // The docs say val is "interpreted as unsigned char".
+                #[allow(clippy::cast_sign_loss, clippy::cast_possible_truncation)]
+                let val = val as u8;
+
+                let idx = this
+                    .read_bytes_ptr_strip_provenance(ptr, Size::from_bytes(num))?
+                    .iter()
+                    .position(|&c| c == val);
+                if let Some(idx) = idx {
+                    let new_ptr = ptr.offset(Size::from_bytes(idx as u64), this)?;
+                    this.write_pointer(new_ptr, dest)?;
+                } else {
+                    this.write_null(dest)?;
+                }
+            }
+            "strlen" => {
+                let [ptr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let n = this.read_c_str(ptr)?.len();
+                this.write_scalar(Scalar::from_machine_usize(u64::try_from(n).unwrap(), this), dest)?;
+            }
+
+            // math functions (note that there are also intrinsics for some other functions)
+            #[rustfmt::skip]
+            | "cbrtf"
+            | "coshf"
+            | "sinhf"
+            | "tanf"
+            | "tanhf"
+            | "acosf"
+            | "asinf"
+            | "atanf"
+            | "log1pf"
+            | "expm1f"
+            => {
+                let [f] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // FIXME: Using host floats.
+                let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
+                let res = match link_name.as_str() {
+                    "cbrtf" => f.cbrt(),
+                    "coshf" => f.cosh(),
+                    "sinhf" => f.sinh(),
+                    "tanf" => f.tan(),
+                    "tanhf" => f.tanh(),
+                    "acosf" => f.acos(),
+                    "asinf" => f.asin(),
+                    "atanf" => f.atan(),
+                    "log1pf" => f.ln_1p(),
+                    "expm1f" => f.exp_m1(),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
+            }
+            #[rustfmt::skip]
+            | "_hypotf"
+            | "hypotf"
+            | "atan2f"
+            | "fdimf"
+            => {
+                let [f1, f2] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // underscore case for windows, here and below
+                // (see https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/floating-point-primitives?view=vs-2019)
+                // FIXME: Using host floats.
+                let f1 = f32::from_bits(this.read_scalar(f1)?.to_u32()?);
+                let f2 = f32::from_bits(this.read_scalar(f2)?.to_u32()?);
+                let res = match link_name.as_str() {
+                    "_hypotf" | "hypotf" => f1.hypot(f2),
+                    "atan2f" => f1.atan2(f2),
+                    #[allow(deprecated)]
+                    "fdimf" => f1.abs_sub(f2),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
+            }
+            #[rustfmt::skip]
+            | "cbrt"
+            | "cosh"
+            | "sinh"
+            | "tan"
+            | "tanh"
+            | "acos"
+            | "asin"
+            | "atan"
+            | "log1p"
+            | "expm1"
+            => {
+                let [f] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // FIXME: Using host floats.
+                let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
+                let res = match link_name.as_str() {
+                    "cbrt" => f.cbrt(),
+                    "cosh" => f.cosh(),
+                    "sinh" => f.sinh(),
+                    "tan" => f.tan(),
+                    "tanh" => f.tanh(),
+                    "acos" => f.acos(),
+                    "asin" => f.asin(),
+                    "atan" => f.atan(),
+                    "log1p" => f.ln_1p(),
+                    "expm1" => f.exp_m1(),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
+            }
+            #[rustfmt::skip]
+            | "_hypot"
+            | "hypot"
+            | "atan2"
+            | "fdim"
+            => {
+                let [f1, f2] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // FIXME: Using host floats.
+                let f1 = f64::from_bits(this.read_scalar(f1)?.to_u64()?);
+                let f2 = f64::from_bits(this.read_scalar(f2)?.to_u64()?);
+                let res = match link_name.as_str() {
+                    "_hypot" | "hypot" => f1.hypot(f2),
+                    "atan2" => f1.atan2(f2),
+                    #[allow(deprecated)]
+                    "fdim" => f1.abs_sub(f2),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
+            }
+            #[rustfmt::skip]
+            | "_ldexp"
+            | "ldexp"
+            | "scalbn"
+            => {
+                let [x, exp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // For radix-2 (binary) systems, `ldexp` and `scalbn` are the same.
+                let x = this.read_scalar(x)?.to_f64()?;
+                let exp = this.read_scalar(exp)?.to_i32()?;
+
+                // Saturating cast to i16. Even those are outside the valid exponent range so
+                // `scalbn` below will do its over/underflow handling.
+                let exp = if exp > i32::from(i16::MAX) {
+                    i16::MAX
+                } else if exp < i32::from(i16::MIN) {
+                    i16::MIN
+                } else {
+                    exp.try_into().unwrap()
+                };
+
+                let res = x.scalbn(exp);
+                this.write_scalar(Scalar::from_f64(res), dest)?;
+            }
+
+            // Architecture-specific shims
+            "llvm.x86.addcarry.64" if this.tcx.sess.target.arch == "x86_64" => {
+                // Computes u8+u64+u64, returning tuple (u8,u64) comprising the output carry and truncated sum.
+                let [c_in, a, b] = this.check_shim(abi, Abi::Unadjusted, link_name, args)?;
+                let c_in = this.read_scalar(c_in)?.to_u8()?;
+                let a = this.read_scalar(a)?.to_u64()?;
+                let b = this.read_scalar(b)?.to_u64()?;
+
+                #[allow(clippy::integer_arithmetic)] // adding two u64 and a u8 cannot wrap in a u128
+                let wide_sum = u128::from(c_in) + u128::from(a) + u128::from(b);
+                #[allow(clippy::integer_arithmetic)] // it's a u128, we can shift by 64
+                let (c_out, sum) = ((wide_sum >> 64).truncate::<u8>(), wide_sum.truncate::<u64>());
+
+                let c_out_field = this.place_field(dest, 0)?;
+                this.write_scalar(Scalar::from_u8(c_out), &c_out_field)?;
+                let sum_field = this.place_field(dest, 1)?;
+                this.write_scalar(Scalar::from_u64(sum), &sum_field)?;
+            }
+            "llvm.x86.sse2.pause" if this.tcx.sess.target.arch == "x86" || this.tcx.sess.target.arch == "x86_64" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.yield_active_thread();
+            }
+            "llvm.aarch64.isb" if this.tcx.sess.target.arch == "aarch64" => {
+                let [arg] = this.check_shim(abi, Abi::Unadjusted, link_name, args)?;
+                let arg = this.read_scalar(arg)?.to_i32()?;
+                match arg {
+                    15 => { // SY ("full system scope")
+                        this.yield_active_thread();
+                    }
+                    _ => {
+                        throw_unsup_format!("unsupported llvm.aarch64.isb argument {}", arg);
+                    }
+                }
+            }
+
+            // Platform-specific shims
+            _ => match this.tcx.sess.target.os.as_ref() {
+                target if target_os_is_unix(target) => return shims::unix::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest),
+                "windows" => return shims::windows::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest),
+                target => throw_unsup_format!("the target `{}` is not supported", target),
+            }
+        };
+        // We only fall through to here if we did *not* hit the `_` arm above,
+        // i.e., if we actually emulated the function with one of the shims.
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+
+    /// Check some basic requirements for this allocation request:
+    /// non-zero size, power-of-two alignment.
+    fn check_alloc_request(size: u64, align: u64) -> InterpResult<'tcx> {
+        if size == 0 {
+            throw_ub_format!("creating allocation with size 0");
+        }
+        if !align.is_power_of_two() {
+            throw_ub_format!("creating allocation with non-power-of-two alignment {}", align);
+        }
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/intrinsics/atomic.rs b/src/tools/miri/src/shims/intrinsics/atomic.rs
new file mode 100644
index 000000000000..50f69bdca363
--- /dev/null
+++ b/src/tools/miri/src/shims/intrinsics/atomic.rs
@@ -0,0 +1,288 @@
+use rustc_middle::{mir, mir::BinOp, ty};
+
+use crate::*;
+use helpers::check_arg_count;
+
+pub enum AtomicOp {
+    /// The `bool` indicates whether the result of the operation should be negated
+    /// (must be a boolean-typed operation).
+    MirOp(mir::BinOp, bool),
+    Max,
+    Min,
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Calls the atomic intrinsic `intrinsic`; the `atomic_` prefix has already been removed.
+    fn emulate_atomic_intrinsic(
+        &mut self,
+        intrinsic_name: &str,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let intrinsic_structure: Vec<_> = intrinsic_name.split('_').collect();
+
+        fn read_ord<'tcx>(ord: &str) -> InterpResult<'tcx, AtomicReadOrd> {
+            Ok(match ord {
+                "seqcst" => AtomicReadOrd::SeqCst,
+                "acquire" => AtomicReadOrd::Acquire,
+                "relaxed" => AtomicReadOrd::Relaxed,
+                _ => throw_unsup_format!("unsupported read ordering `{ord}`"),
+            })
+        }
+
+        fn write_ord<'tcx>(ord: &str) -> InterpResult<'tcx, AtomicWriteOrd> {
+            Ok(match ord {
+                "seqcst" => AtomicWriteOrd::SeqCst,
+                "release" => AtomicWriteOrd::Release,
+                "relaxed" => AtomicWriteOrd::Relaxed,
+                _ => throw_unsup_format!("unsupported write ordering `{ord}`"),
+            })
+        }
+
+        fn rw_ord<'tcx>(ord: &str) -> InterpResult<'tcx, AtomicRwOrd> {
+            Ok(match ord {
+                "seqcst" => AtomicRwOrd::SeqCst,
+                "acqrel" => AtomicRwOrd::AcqRel,
+                "acquire" => AtomicRwOrd::Acquire,
+                "release" => AtomicRwOrd::Release,
+                "relaxed" => AtomicRwOrd::Relaxed,
+                _ => throw_unsup_format!("unsupported read-write ordering `{ord}`"),
+            })
+        }
+
+        fn fence_ord<'tcx>(ord: &str) -> InterpResult<'tcx, AtomicFenceOrd> {
+            Ok(match ord {
+                "seqcst" => AtomicFenceOrd::SeqCst,
+                "acqrel" => AtomicFenceOrd::AcqRel,
+                "acquire" => AtomicFenceOrd::Acquire,
+                "release" => AtomicFenceOrd::Release,
+                _ => throw_unsup_format!("unsupported fence ordering `{ord}`"),
+            })
+        }
+
+        match &*intrinsic_structure {
+            ["load", ord] => this.atomic_load(args, dest, read_ord(ord)?)?,
+            ["store", ord] => this.atomic_store(args, write_ord(ord)?)?,
+
+            ["fence", ord] => this.atomic_fence_intrinsic(args, fence_ord(ord)?)?,
+            ["singlethreadfence", ord] => this.compiler_fence_intrinsic(args, fence_ord(ord)?)?,
+
+            ["xchg", ord] => this.atomic_exchange(args, dest, rw_ord(ord)?)?,
+            ["cxchg", ord1, ord2] =>
+                this.atomic_compare_exchange(args, dest, rw_ord(ord1)?, read_ord(ord2)?)?,
+            ["cxchgweak", ord1, ord2] =>
+                this.atomic_compare_exchange_weak(args, dest, rw_ord(ord1)?, read_ord(ord2)?)?,
+
+            ["or", ord] =>
+                this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), rw_ord(ord)?)?,
+            ["xor", ord] =>
+                this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), rw_ord(ord)?)?,
+            ["and", ord] =>
+                this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), rw_ord(ord)?)?,
+            ["nand", ord] =>
+                this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), rw_ord(ord)?)?,
+            ["xadd", ord] =>
+                this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), rw_ord(ord)?)?,
+            ["xsub", ord] =>
+                this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), rw_ord(ord)?)?,
+            ["min", ord] => {
+                // Later we will use the type to indicate signed vs unsigned,
+                // so make sure it matches the intrinsic name.
+                assert!(matches!(args[1].layout.ty.kind(), ty::Int(_)));
+                this.atomic_op(args, dest, AtomicOp::Min, rw_ord(ord)?)?;
+            }
+            ["umin", ord] => {
+                // Later we will use the type to indicate signed vs unsigned,
+                // so make sure it matches the intrinsic name.
+                assert!(matches!(args[1].layout.ty.kind(), ty::Uint(_)));
+                this.atomic_op(args, dest, AtomicOp::Min, rw_ord(ord)?)?;
+            }
+            ["max", ord] => {
+                // Later we will use the type to indicate signed vs unsigned,
+                // so make sure it matches the intrinsic name.
+                assert!(matches!(args[1].layout.ty.kind(), ty::Int(_)));
+                this.atomic_op(args, dest, AtomicOp::Max, rw_ord(ord)?)?;
+            }
+            ["umax", ord] => {
+                // Later we will use the type to indicate signed vs unsigned,
+                // so make sure it matches the intrinsic name.
+                assert!(matches!(args[1].layout.ty.kind(), ty::Uint(_)));
+                this.atomic_op(args, dest, AtomicOp::Max, rw_ord(ord)?)?;
+            }
+
+            _ => throw_unsup_format!("unimplemented intrinsic: `atomic_{intrinsic_name}`"),
+        }
+        Ok(())
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextPrivExt<'mir, 'tcx> for MiriInterpCx<'mir, 'tcx> {}
+trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
+    fn atomic_load(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        atomic: AtomicReadOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let [place] = check_arg_count(args)?;
+        let place = this.deref_operand(place)?;
+
+        // Perform atomic load.
+        let val = this.read_scalar_atomic(&place, atomic)?;
+        // Perform regular store.
+        this.write_scalar(val, dest)?;
+        Ok(())
+    }
+
+    fn atomic_store(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        atomic: AtomicWriteOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let [place, val] = check_arg_count(args)?;
+        let place = this.deref_operand(place)?;
+
+        // Perform regular load.
+        let val = this.read_scalar(val)?;
+        // Perform atomic store
+        this.write_scalar_atomic(val, &place, atomic)?;
+        Ok(())
+    }
+
+    fn compiler_fence_intrinsic(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        atomic: AtomicFenceOrd,
+    ) -> InterpResult<'tcx> {
+        let [] = check_arg_count(args)?;
+        let _ = atomic;
+        //FIXME: compiler fences are currently ignored
+        Ok(())
+    }
+
+    fn atomic_fence_intrinsic(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        atomic: AtomicFenceOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let [] = check_arg_count(args)?;
+        this.atomic_fence(atomic)?;
+        Ok(())
+    }
+
+    fn atomic_op(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        atomic_op: AtomicOp,
+        atomic: AtomicRwOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let [place, rhs] = check_arg_count(args)?;
+        let place = this.deref_operand(place)?;
+        let rhs = this.read_immediate(rhs)?;
+
+        if !place.layout.ty.is_integral() && !place.layout.ty.is_unsafe_ptr() {
+            span_bug!(
+                this.cur_span(),
+                "atomic arithmetic operations only work on integer and raw pointer types",
+            );
+        }
+        if rhs.layout.ty != place.layout.ty {
+            span_bug!(this.cur_span(), "atomic arithmetic operation type mismatch");
+        }
+
+        match atomic_op {
+            AtomicOp::Min => {
+                let old = this.atomic_min_max_scalar(&place, rhs, true, atomic)?;
+                this.write_immediate(*old, dest)?; // old value is returned
+                Ok(())
+            }
+            AtomicOp::Max => {
+                let old = this.atomic_min_max_scalar(&place, rhs, false, atomic)?;
+                this.write_immediate(*old, dest)?; // old value is returned
+                Ok(())
+            }
+            AtomicOp::MirOp(op, neg) => {
+                let old = this.atomic_op_immediate(&place, &rhs, op, neg, atomic)?;
+                this.write_immediate(*old, dest)?; // old value is returned
+                Ok(())
+            }
+        }
+    }
+
+    fn atomic_exchange(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        atomic: AtomicRwOrd,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let [place, new] = check_arg_count(args)?;
+        let place = this.deref_operand(place)?;
+        let new = this.read_scalar(new)?;
+
+        let old = this.atomic_exchange_scalar(&place, new, atomic)?;
+        this.write_scalar(old, dest)?; // old value is returned
+        Ok(())
+    }
+
+    fn atomic_compare_exchange_impl(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        success: AtomicRwOrd,
+        fail: AtomicReadOrd,
+        can_fail_spuriously: bool,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let [place, expect_old, new] = check_arg_count(args)?;
+        let place = this.deref_operand(place)?;
+        let expect_old = this.read_immediate(expect_old)?; // read as immediate for the sake of `binary_op()`
+        let new = this.read_scalar(new)?;
+
+        let old = this.atomic_compare_exchange_scalar(
+            &place,
+            &expect_old,
+            new,
+            success,
+            fail,
+            can_fail_spuriously,
+        )?;
+
+        // Return old value.
+        this.write_immediate(old, dest)?;
+        Ok(())
+    }
+
+    fn atomic_compare_exchange(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        success: AtomicRwOrd,
+        fail: AtomicReadOrd,
+    ) -> InterpResult<'tcx> {
+        self.atomic_compare_exchange_impl(args, dest, success, fail, false)
+    }
+
+    fn atomic_compare_exchange_weak(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        success: AtomicRwOrd,
+        fail: AtomicReadOrd,
+    ) -> InterpResult<'tcx> {
+        self.atomic_compare_exchange_impl(args, dest, success, fail, true)
+    }
+}
diff --git a/src/tools/miri/src/shims/intrinsics/mod.rs b/src/tools/miri/src/shims/intrinsics/mod.rs
new file mode 100644
index 000000000000..e0985ace5be7
--- /dev/null
+++ b/src/tools/miri/src/shims/intrinsics/mod.rs
@@ -0,0 +1,429 @@
+mod atomic;
+mod simd;
+
+use std::iter;
+
+use log::trace;
+
+use rustc_apfloat::{Float, Round};
+use rustc_middle::ty::layout::{IntegerExt, LayoutOf};
+use rustc_middle::{
+    mir,
+    ty::{self, FloatTy, Ty},
+};
+use rustc_target::abi::Integer;
+
+use crate::*;
+use atomic::EvalContextExt as _;
+use helpers::check_arg_count;
+use simd::EvalContextExt as _;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_intrinsic(
+        &mut self,
+        instance: ty::Instance<'tcx>,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        _unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        // See if the core engine can handle this intrinsic.
+        if this.emulate_intrinsic(instance, args, dest, ret)? {
+            return Ok(());
+        }
+
+        // All remaining supported intrinsics have a return place.
+        let intrinsic_name = this.tcx.item_name(instance.def_id());
+        let intrinsic_name = intrinsic_name.as_str();
+        let ret = match ret {
+            None => throw_unsup_format!("unimplemented (diverging) intrinsic: `{intrinsic_name}`"),
+            Some(p) => p,
+        };
+
+        // Some intrinsics are special and need the "ret".
+        match intrinsic_name {
+            "try" => return this.handle_try(args, dest, ret),
+            _ => {}
+        }
+
+        // The rest jumps to `ret` immediately.
+        this.emulate_intrinsic_by_name(intrinsic_name, args, dest)?;
+
+        trace!("{:?}", this.dump_place(**dest));
+        this.go_to_block(ret);
+        Ok(())
+    }
+
+    /// Emulates a Miri-supported intrinsic (not supported by the core engine).
+    fn emulate_intrinsic_by_name(
+        &mut self,
+        intrinsic_name: &str,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        if let Some(name) = intrinsic_name.strip_prefix("atomic_") {
+            return this.emulate_atomic_intrinsic(name, args, dest);
+        }
+        if let Some(name) = intrinsic_name.strip_prefix("simd_") {
+            return this.emulate_simd_intrinsic(name, args, dest);
+        }
+
+        match intrinsic_name {
+            // Miri overwriting CTFE intrinsics.
+            "ptr_guaranteed_cmp" => {
+                let [left, right] = check_arg_count(args)?;
+                let left = this.read_immediate(left)?;
+                let right = this.read_immediate(right)?;
+                let (val, _overflowed, _ty) =
+                    this.overflowing_binary_op(mir::BinOp::Eq, &left, &right)?;
+                // We're type punning a bool as an u8 here.
+                this.write_scalar(val, dest)?;
+            }
+            "const_allocate" => {
+                // For now, for compatibility with the run-time implementation of this, we just return null.
+                // See <https://github.com/rust-lang/rust/issues/93935>.
+                this.write_null(dest)?;
+            }
+            "const_deallocate" => {
+                // complete NOP
+            }
+
+            // Raw memory accesses
+            "volatile_load" => {
+                let [place] = check_arg_count(args)?;
+                let place = this.deref_operand(place)?;
+                this.copy_op(&place.into(), dest, /*allow_transmute*/ false)?;
+            }
+            "volatile_store" => {
+                let [place, dest] = check_arg_count(args)?;
+                let place = this.deref_operand(place)?;
+                this.copy_op(dest, &place.into(), /*allow_transmute*/ false)?;
+            }
+
+            "write_bytes" | "volatile_set_memory" => {
+                let [ptr, val_byte, count] = check_arg_count(args)?;
+                let ty = ptr.layout.ty.builtin_deref(true).unwrap().ty;
+                let ty_layout = this.layout_of(ty)?;
+                let val_byte = this.read_scalar(val_byte)?.to_u8()?;
+                let ptr = this.read_pointer(ptr)?;
+                let count = this.read_scalar(count)?.to_machine_usize(this)?;
+                // `checked_mul` enforces a too small bound (the correct one would probably be machine_isize_max),
+                // but no actual allocation can be big enough for the difference to be noticeable.
+                let byte_count = ty_layout.size.checked_mul(count, this).ok_or_else(|| {
+                    err_ub_format!("overflow computing total size of `{intrinsic_name}`")
+                })?;
+                this.write_bytes_ptr(ptr, iter::repeat(val_byte).take(byte_count.bytes_usize()))?;
+            }
+
+            // Floating-point operations
+            "fabsf32" => {
+                let [f] = check_arg_count(args)?;
+                let f = this.read_scalar(f)?.to_f32()?;
+                // Can be implemented in soft-floats.
+                this.write_scalar(Scalar::from_f32(f.abs()), dest)?;
+            }
+            "fabsf64" => {
+                let [f] = check_arg_count(args)?;
+                let f = this.read_scalar(f)?.to_f64()?;
+                // Can be implemented in soft-floats.
+                this.write_scalar(Scalar::from_f64(f.abs()), dest)?;
+            }
+            #[rustfmt::skip]
+            | "sinf32"
+            | "cosf32"
+            | "sqrtf32"
+            | "expf32"
+            | "exp2f32"
+            | "logf32"
+            | "log10f32"
+            | "log2f32"
+            | "floorf32"
+            | "ceilf32"
+            | "truncf32"
+            | "roundf32"
+            => {
+                let [f] = check_arg_count(args)?;
+                // FIXME: Using host floats.
+                let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
+                let f = match intrinsic_name {
+                    "sinf32" => f.sin(),
+                    "cosf32" => f.cos(),
+                    "sqrtf32" => f.sqrt(),
+                    "expf32" => f.exp(),
+                    "exp2f32" => f.exp2(),
+                    "logf32" => f.ln(),
+                    "log10f32" => f.log10(),
+                    "log2f32" => f.log2(),
+                    "floorf32" => f.floor(),
+                    "ceilf32" => f.ceil(),
+                    "truncf32" => f.trunc(),
+                    "roundf32" => f.round(),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
+            }
+
+            #[rustfmt::skip]
+            | "sinf64"
+            | "cosf64"
+            | "sqrtf64"
+            | "expf64"
+            | "exp2f64"
+            | "logf64"
+            | "log10f64"
+            | "log2f64"
+            | "floorf64"
+            | "ceilf64"
+            | "truncf64"
+            | "roundf64"
+            => {
+                let [f] = check_arg_count(args)?;
+                // FIXME: Using host floats.
+                let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
+                let f = match intrinsic_name {
+                    "sinf64" => f.sin(),
+                    "cosf64" => f.cos(),
+                    "sqrtf64" => f.sqrt(),
+                    "expf64" => f.exp(),
+                    "exp2f64" => f.exp2(),
+                    "logf64" => f.ln(),
+                    "log10f64" => f.log10(),
+                    "log2f64" => f.log2(),
+                    "floorf64" => f.floor(),
+                    "ceilf64" => f.ceil(),
+                    "truncf64" => f.trunc(),
+                    "roundf64" => f.round(),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
+            }
+
+            #[rustfmt::skip]
+            | "fadd_fast"
+            | "fsub_fast"
+            | "fmul_fast"
+            | "fdiv_fast"
+            | "frem_fast"
+            => {
+                let [a, b] = check_arg_count(args)?;
+                let a = this.read_immediate(a)?;
+                let b = this.read_immediate(b)?;
+                let op = match intrinsic_name {
+                    "fadd_fast" => mir::BinOp::Add,
+                    "fsub_fast" => mir::BinOp::Sub,
+                    "fmul_fast" => mir::BinOp::Mul,
+                    "fdiv_fast" => mir::BinOp::Div,
+                    "frem_fast" => mir::BinOp::Rem,
+                    _ => bug!(),
+                };
+                let float_finite = |x: &ImmTy<'tcx, _>| -> InterpResult<'tcx, bool> {
+                    Ok(match x.layout.ty.kind() {
+                        ty::Float(FloatTy::F32) => x.to_scalar().to_f32()?.is_finite(),
+                        ty::Float(FloatTy::F64) => x.to_scalar().to_f64()?.is_finite(),
+                        _ => bug!(
+                            "`{intrinsic_name}` called with non-float input type {ty:?}",
+                            ty = x.layout.ty,
+                        ),
+                    })
+                };
+                match (float_finite(&a)?, float_finite(&b)?) {
+                    (false, false) => throw_ub_format!(
+                        "`{intrinsic_name}` intrinsic called with non-finite value as both parameters",
+                    ),
+                    (false, _) => throw_ub_format!(
+                        "`{intrinsic_name}` intrinsic called with non-finite value as first parameter",
+                    ),
+                    (_, false) => throw_ub_format!(
+                        "`{intrinsic_name}` intrinsic called with non-finite value as second parameter",
+                    ),
+                    _ => {}
+                }
+                this.binop_ignore_overflow(op, &a, &b, dest)?;
+            }
+
+            #[rustfmt::skip]
+            | "minnumf32"
+            | "maxnumf32"
+            | "copysignf32"
+            => {
+                let [a, b] = check_arg_count(args)?;
+                let a = this.read_scalar(a)?.to_f32()?;
+                let b = this.read_scalar(b)?.to_f32()?;
+                let res = match intrinsic_name {
+                    "minnumf32" => a.min(b),
+                    "maxnumf32" => a.max(b),
+                    "copysignf32" => a.copy_sign(b),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_f32(res), dest)?;
+            }
+
+            #[rustfmt::skip]
+            | "minnumf64"
+            | "maxnumf64"
+            | "copysignf64"
+            => {
+                let [a, b] = check_arg_count(args)?;
+                let a = this.read_scalar(a)?.to_f64()?;
+                let b = this.read_scalar(b)?.to_f64()?;
+                let res = match intrinsic_name {
+                    "minnumf64" => a.min(b),
+                    "maxnumf64" => a.max(b),
+                    "copysignf64" => a.copy_sign(b),
+                    _ => bug!(),
+                };
+                this.write_scalar(Scalar::from_f64(res), dest)?;
+            }
+
+            "powf32" => {
+                let [f, f2] = check_arg_count(args)?;
+                // FIXME: Using host floats.
+                let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
+                let f2 = f32::from_bits(this.read_scalar(f2)?.to_u32()?);
+                let res = f.powf(f2);
+                this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
+            }
+
+            "powf64" => {
+                let [f, f2] = check_arg_count(args)?;
+                // FIXME: Using host floats.
+                let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
+                let f2 = f64::from_bits(this.read_scalar(f2)?.to_u64()?);
+                let res = f.powf(f2);
+                this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
+            }
+
+            "fmaf32" => {
+                let [a, b, c] = check_arg_count(args)?;
+                // FIXME: Using host floats, to work around https://github.com/rust-lang/miri/issues/2468.
+                let a = f32::from_bits(this.read_scalar(a)?.to_u32()?);
+                let b = f32::from_bits(this.read_scalar(b)?.to_u32()?);
+                let c = f32::from_bits(this.read_scalar(c)?.to_u32()?);
+                let res = a.mul_add(b, c);
+                this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
+            }
+
+            "fmaf64" => {
+                let [a, b, c] = check_arg_count(args)?;
+                // FIXME: Using host floats, to work around https://github.com/rust-lang/miri/issues/2468.
+                let a = f64::from_bits(this.read_scalar(a)?.to_u64()?);
+                let b = f64::from_bits(this.read_scalar(b)?.to_u64()?);
+                let c = f64::from_bits(this.read_scalar(c)?.to_u64()?);
+                let res = a.mul_add(b, c);
+                this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
+            }
+
+            "powif32" => {
+                let [f, i] = check_arg_count(args)?;
+                // FIXME: Using host floats.
+                let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
+                let i = this.read_scalar(i)?.to_i32()?;
+                let res = f.powi(i);
+                this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
+            }
+
+            "powif64" => {
+                let [f, i] = check_arg_count(args)?;
+                // FIXME: Using host floats.
+                let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
+                let i = this.read_scalar(i)?.to_i32()?;
+                let res = f.powi(i);
+                this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
+            }
+
+            "float_to_int_unchecked" => {
+                let [val] = check_arg_count(args)?;
+                let val = this.read_immediate(val)?;
+
+                let res = match val.layout.ty.kind() {
+                    ty::Float(FloatTy::F32) =>
+                        this.float_to_int_unchecked(val.to_scalar().to_f32()?, dest.layout.ty)?,
+                    ty::Float(FloatTy::F64) =>
+                        this.float_to_int_unchecked(val.to_scalar().to_f64()?, dest.layout.ty)?,
+                    _ =>
+                        span_bug!(
+                            this.cur_span(),
+                            "`float_to_int_unchecked` called with non-float input type {:?}",
+                            val.layout.ty
+                        ),
+                };
+
+                this.write_scalar(res, dest)?;
+            }
+
+            // Other
+            "exact_div" => {
+                let [num, denom] = check_arg_count(args)?;
+                this.exact_div(&this.read_immediate(num)?, &this.read_immediate(denom)?, dest)?;
+            }
+
+            "breakpoint" => {
+                let [] = check_arg_count(args)?;
+                // normally this would raise a SIGTRAP, which aborts if no debugger is connected
+                throw_machine_stop!(TerminationInfo::Abort(format!("Trace/breakpoint trap")))
+            }
+
+            name => throw_unsup_format!("unimplemented intrinsic: `{name}`"),
+        }
+
+        Ok(())
+    }
+
+    fn float_to_int_unchecked<F>(
+        &self,
+        f: F,
+        dest_ty: Ty<'tcx>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>>
+    where
+        F: Float + Into<Scalar<Provenance>>,
+    {
+        let this = self.eval_context_ref();
+
+        // Step 1: cut off the fractional part of `f`. The result of this is
+        // guaranteed to be precisely representable in IEEE floats.
+        let f = f.round_to_integral(Round::TowardZero).value;
+
+        // Step 2: Cast the truncated float to the target integer type and see if we lose any information in this step.
+        Ok(match dest_ty.kind() {
+            // Unsigned
+            ty::Uint(t) => {
+                let size = Integer::from_uint_ty(this, *t).size();
+                let res = f.to_u128(size.bits_usize());
+                if res.status.is_empty() {
+                    // No status flags means there was no further rounding or other loss of precision.
+                    Scalar::from_uint(res.value, size)
+                } else {
+                    // `f` was not representable in this integer type.
+                    throw_ub_format!(
+                        "`float_to_int_unchecked` intrinsic called on {f} which cannot be represented in target type `{dest_ty:?}`",
+                    );
+                }
+            }
+            // Signed
+            ty::Int(t) => {
+                let size = Integer::from_int_ty(this, *t).size();
+                let res = f.to_i128(size.bits_usize());
+                if res.status.is_empty() {
+                    // No status flags means there was no further rounding or other loss of precision.
+                    Scalar::from_int(res.value, size)
+                } else {
+                    // `f` was not representable in this integer type.
+                    throw_ub_format!(
+                        "`float_to_int_unchecked` intrinsic called on {f} which cannot be represented in target type `{dest_ty:?}`",
+                    );
+                }
+            }
+            // Nothing else
+            _ =>
+                span_bug!(
+                    this.cur_span(),
+                    "`float_to_int_unchecked` called with non-int output type {dest_ty:?}"
+                ),
+        })
+    }
+}
diff --git a/src/tools/miri/src/shims/intrinsics/simd.rs b/src/tools/miri/src/shims/intrinsics/simd.rs
new file mode 100644
index 000000000000..163d185f66f3
--- /dev/null
+++ b/src/tools/miri/src/shims/intrinsics/simd.rs
@@ -0,0 +1,627 @@
+use rustc_apfloat::Float;
+use rustc_middle::ty::layout::{HasParamEnv, LayoutOf};
+use rustc_middle::{mir, ty, ty::FloatTy};
+use rustc_target::abi::{Endian, HasDataLayout, Size};
+
+use crate::*;
+use helpers::check_arg_count;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Calls the simd intrinsic `intrinsic`; the `simd_` prefix has already been removed.
+    fn emulate_simd_intrinsic(
+        &mut self,
+        intrinsic_name: &str,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        match intrinsic_name {
+            #[rustfmt::skip]
+            | "neg"
+            | "fabs"
+            | "ceil"
+            | "floor"
+            | "round"
+            | "trunc"
+            | "fsqrt" => {
+                let [op] = check_arg_count(args)?;
+                let (op, op_len) = this.operand_to_simd(op)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                assert_eq!(dest_len, op_len);
+
+                #[derive(Copy, Clone)]
+                enum HostFloatOp {
+                    Ceil,
+                    Floor,
+                    Round,
+                    Trunc,
+                    Sqrt,
+                }
+                #[derive(Copy, Clone)]
+                enum Op {
+                    MirOp(mir::UnOp),
+                    Abs,
+                    HostOp(HostFloatOp),
+                }
+                let which = match intrinsic_name {
+                    "neg" => Op::MirOp(mir::UnOp::Neg),
+                    "fabs" => Op::Abs,
+                    "ceil" => Op::HostOp(HostFloatOp::Ceil),
+                    "floor" => Op::HostOp(HostFloatOp::Floor),
+                    "round" => Op::HostOp(HostFloatOp::Round),
+                    "trunc" => Op::HostOp(HostFloatOp::Trunc),
+                    "fsqrt" => Op::HostOp(HostFloatOp::Sqrt),
+                    _ => unreachable!(),
+                };
+
+                for i in 0..dest_len {
+                    let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
+                    let dest = this.mplace_index(&dest, i)?;
+                    let val = match which {
+                        Op::MirOp(mir_op) => this.unary_op(mir_op, &op)?.to_scalar(),
+                        Op::Abs => {
+                            // Works for f32 and f64.
+                            let ty::Float(float_ty) = op.layout.ty.kind() else {
+                                span_bug!(this.cur_span(), "{} operand is not a float", intrinsic_name)
+                            };
+                            let op = op.to_scalar();
+                            match float_ty {
+                                FloatTy::F32 => Scalar::from_f32(op.to_f32()?.abs()),
+                                FloatTy::F64 => Scalar::from_f64(op.to_f64()?.abs()),
+                            }
+                        }
+                        Op::HostOp(host_op) => {
+                            let ty::Float(float_ty) = op.layout.ty.kind() else {
+                                span_bug!(this.cur_span(), "{} operand is not a float", intrinsic_name)
+                            };
+                            // FIXME using host floats
+                            match float_ty {
+                                FloatTy::F32 => {
+                                    let f = f32::from_bits(op.to_scalar().to_u32()?);
+                                    let res = match host_op {
+                                        HostFloatOp::Ceil => f.ceil(),
+                                        HostFloatOp::Floor => f.floor(),
+                                        HostFloatOp::Round => f.round(),
+                                        HostFloatOp::Trunc => f.trunc(),
+                                        HostFloatOp::Sqrt => f.sqrt(),
+                                    };
+                                    Scalar::from_u32(res.to_bits())
+                                }
+                                FloatTy::F64 => {
+                                    let f = f64::from_bits(op.to_scalar().to_u64()?);
+                                    let res = match host_op {
+                                        HostFloatOp::Ceil => f.ceil(),
+                                        HostFloatOp::Floor => f.floor(),
+                                        HostFloatOp::Round => f.round(),
+                                        HostFloatOp::Trunc => f.trunc(),
+                                        HostFloatOp::Sqrt => f.sqrt(),
+                                    };
+                                    Scalar::from_u64(res.to_bits())
+                                }
+                            }
+
+                        }
+                    };
+                    this.write_scalar(val, &dest.into())?;
+                }
+            }
+            #[rustfmt::skip]
+            | "add"
+            | "sub"
+            | "mul"
+            | "div"
+            | "rem"
+            | "shl"
+            | "shr"
+            | "and"
+            | "or"
+            | "xor"
+            | "eq"
+            | "ne"
+            | "lt"
+            | "le"
+            | "gt"
+            | "ge"
+            | "fmax"
+            | "fmin"
+            | "saturating_add"
+            | "saturating_sub"
+            | "arith_offset" => {
+                use mir::BinOp;
+
+                let [left, right] = check_arg_count(args)?;
+                let (left, left_len) = this.operand_to_simd(left)?;
+                let (right, right_len) = this.operand_to_simd(right)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                assert_eq!(dest_len, left_len);
+                assert_eq!(dest_len, right_len);
+
+                enum Op {
+                    MirOp(BinOp),
+                    SaturatingOp(BinOp),
+                    FMax,
+                    FMin,
+                    WrappingOffset,
+                }
+                let which = match intrinsic_name {
+                    "add" => Op::MirOp(BinOp::Add),
+                    "sub" => Op::MirOp(BinOp::Sub),
+                    "mul" => Op::MirOp(BinOp::Mul),
+                    "div" => Op::MirOp(BinOp::Div),
+                    "rem" => Op::MirOp(BinOp::Rem),
+                    "shl" => Op::MirOp(BinOp::Shl),
+                    "shr" => Op::MirOp(BinOp::Shr),
+                    "and" => Op::MirOp(BinOp::BitAnd),
+                    "or" => Op::MirOp(BinOp::BitOr),
+                    "xor" => Op::MirOp(BinOp::BitXor),
+                    "eq" => Op::MirOp(BinOp::Eq),
+                    "ne" => Op::MirOp(BinOp::Ne),
+                    "lt" => Op::MirOp(BinOp::Lt),
+                    "le" => Op::MirOp(BinOp::Le),
+                    "gt" => Op::MirOp(BinOp::Gt),
+                    "ge" => Op::MirOp(BinOp::Ge),
+                    "fmax" => Op::FMax,
+                    "fmin" => Op::FMin,
+                    "saturating_add" => Op::SaturatingOp(BinOp::Add),
+                    "saturating_sub" => Op::SaturatingOp(BinOp::Sub),
+                    "arith_offset" => Op::WrappingOffset,
+                    _ => unreachable!(),
+                };
+
+                for i in 0..dest_len {
+                    let left = this.read_immediate(&this.mplace_index(&left, i)?.into())?;
+                    let right = this.read_immediate(&this.mplace_index(&right, i)?.into())?;
+                    let dest = this.mplace_index(&dest, i)?;
+                    let val = match which {
+                        Op::MirOp(mir_op) => {
+                            let (val, overflowed, ty) = this.overflowing_binary_op(mir_op, &left, &right)?;
+                            if matches!(mir_op, BinOp::Shl | BinOp::Shr) {
+                                // Shifts have extra UB as SIMD operations that the MIR binop does not have.
+                                // See <https://github.com/rust-lang/rust/issues/91237>.
+                                if overflowed {
+                                    let r_val = right.to_scalar().to_bits(right.layout.size)?;
+                                    throw_ub_format!("overflowing shift by {r_val} in `simd_{intrinsic_name}` in SIMD lane {i}");
+                                }
+                            }
+                            if matches!(mir_op, BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge) {
+                                // Special handling for boolean-returning operations
+                                assert_eq!(ty, this.tcx.types.bool);
+                                let val = val.to_bool().unwrap();
+                                bool_to_simd_element(val, dest.layout.size)
+                            } else {
+                                assert_ne!(ty, this.tcx.types.bool);
+                                assert_eq!(ty, dest.layout.ty);
+                                val
+                            }
+                        }
+                        Op::SaturatingOp(mir_op) => {
+                            this.saturating_arith(mir_op, &left, &right)?
+                        }
+                        Op::WrappingOffset => {
+                            let ptr = left.to_scalar().to_pointer(this)?;
+                            let offset_count = right.to_scalar().to_machine_isize(this)?;
+                            let pointee_ty = left.layout.ty.builtin_deref(true).unwrap().ty;
+
+                            let pointee_size = i64::try_from(this.layout_of(pointee_ty)?.size.bytes()).unwrap();
+                            let offset_bytes = offset_count.wrapping_mul(pointee_size);
+                            let offset_ptr = ptr.wrapping_signed_offset(offset_bytes, this);
+                            Scalar::from_maybe_pointer(offset_ptr, this)
+                        }
+                        Op::FMax => {
+                            fmax_op(&left, &right)?
+                        }
+                        Op::FMin => {
+                            fmin_op(&left, &right)?
+                        }
+                    };
+                    this.write_scalar(val, &dest.into())?;
+                }
+            }
+            "fma" => {
+                let [a, b, c] = check_arg_count(args)?;
+                let (a, a_len) = this.operand_to_simd(a)?;
+                let (b, b_len) = this.operand_to_simd(b)?;
+                let (c, c_len) = this.operand_to_simd(c)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                assert_eq!(dest_len, a_len);
+                assert_eq!(dest_len, b_len);
+                assert_eq!(dest_len, c_len);
+
+                for i in 0..dest_len {
+                    let a = this.read_scalar(&this.mplace_index(&a, i)?.into())?;
+                    let b = this.read_scalar(&this.mplace_index(&b, i)?.into())?;
+                    let c = this.read_scalar(&this.mplace_index(&c, i)?.into())?;
+                    let dest = this.mplace_index(&dest, i)?;
+
+                    // Works for f32 and f64.
+                    // FIXME: using host floats to work around https://github.com/rust-lang/miri/issues/2468.
+                    let ty::Float(float_ty) = dest.layout.ty.kind() else {
+                        span_bug!(this.cur_span(), "{} operand is not a float", intrinsic_name)
+                    };
+                    let val = match float_ty {
+                        FloatTy::F32 => {
+                            let a = f32::from_bits(a.to_u32()?);
+                            let b = f32::from_bits(b.to_u32()?);
+                            let c = f32::from_bits(c.to_u32()?);
+                            let res = a.mul_add(b, c);
+                            Scalar::from_u32(res.to_bits())
+                        }
+                        FloatTy::F64 => {
+                            let a = f64::from_bits(a.to_u64()?);
+                            let b = f64::from_bits(b.to_u64()?);
+                            let c = f64::from_bits(c.to_u64()?);
+                            let res = a.mul_add(b, c);
+                            Scalar::from_u64(res.to_bits())
+                        }
+                    };
+                    this.write_scalar(val, &dest.into())?;
+                }
+            }
+            #[rustfmt::skip]
+            | "reduce_and"
+            | "reduce_or"
+            | "reduce_xor"
+            | "reduce_any"
+            | "reduce_all"
+            | "reduce_max"
+            | "reduce_min" => {
+                use mir::BinOp;
+
+                let [op] = check_arg_count(args)?;
+                let (op, op_len) = this.operand_to_simd(op)?;
+
+                let imm_from_bool =
+                    |b| ImmTy::from_scalar(Scalar::from_bool(b), this.machine.layouts.bool);
+
+                enum Op {
+                    MirOp(BinOp),
+                    MirOpBool(BinOp),
+                    Max,
+                    Min,
+                }
+                let which = match intrinsic_name {
+                    "reduce_and" => Op::MirOp(BinOp::BitAnd),
+                    "reduce_or" => Op::MirOp(BinOp::BitOr),
+                    "reduce_xor" => Op::MirOp(BinOp::BitXor),
+                    "reduce_any" => Op::MirOpBool(BinOp::BitOr),
+                    "reduce_all" => Op::MirOpBool(BinOp::BitAnd),
+                    "reduce_max" => Op::Max,
+                    "reduce_min" => Op::Min,
+                    _ => unreachable!(),
+                };
+
+                // Initialize with first lane, then proceed with the rest.
+                let mut res = this.read_immediate(&this.mplace_index(&op, 0)?.into())?;
+                if matches!(which, Op::MirOpBool(_)) {
+                    // Convert to `bool` scalar.
+                    res = imm_from_bool(simd_element_to_bool(res)?);
+                }
+                for i in 1..op_len {
+                    let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
+                    res = match which {
+                        Op::MirOp(mir_op) => {
+                            this.binary_op(mir_op, &res, &op)?
+                        }
+                        Op::MirOpBool(mir_op) => {
+                            let op = imm_from_bool(simd_element_to_bool(op)?);
+                            this.binary_op(mir_op, &res, &op)?
+                        }
+                        Op::Max => {
+                            if matches!(res.layout.ty.kind(), ty::Float(_)) {
+                                ImmTy::from_scalar(fmax_op(&res, &op)?, res.layout)
+                            } else {
+                                // Just boring integers, so NaNs to worry about
+                                if this.binary_op(BinOp::Ge, &res, &op)?.to_scalar().to_bool()? {
+                                    res
+                                } else {
+                                    op
+                                }
+                            }
+                        }
+                        Op::Min => {
+                            if matches!(res.layout.ty.kind(), ty::Float(_)) {
+                                ImmTy::from_scalar(fmin_op(&res, &op)?, res.layout)
+                            } else {
+                                // Just boring integers, so NaNs to worry about
+                                if this.binary_op(BinOp::Le, &res, &op)?.to_scalar().to_bool()? {
+                                    res
+                                } else {
+                                    op
+                                }
+                            }
+                        }
+                    };
+                }
+                this.write_immediate(*res, dest)?;
+            }
+            #[rustfmt::skip]
+            | "reduce_add_ordered"
+            | "reduce_mul_ordered" => {
+                use mir::BinOp;
+
+                let [op, init] = check_arg_count(args)?;
+                let (op, op_len) = this.operand_to_simd(op)?;
+                let init = this.read_immediate(init)?;
+
+                let mir_op = match intrinsic_name {
+                    "reduce_add_ordered" => BinOp::Add,
+                    "reduce_mul_ordered" => BinOp::Mul,
+                    _ => unreachable!(),
+                };
+
+                let mut res = init;
+                for i in 0..op_len {
+                    let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
+                    res = this.binary_op(mir_op, &res, &op)?;
+                }
+                this.write_immediate(*res, dest)?;
+            }
+            "select" => {
+                let [mask, yes, no] = check_arg_count(args)?;
+                let (mask, mask_len) = this.operand_to_simd(mask)?;
+                let (yes, yes_len) = this.operand_to_simd(yes)?;
+                let (no, no_len) = this.operand_to_simd(no)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                assert_eq!(dest_len, mask_len);
+                assert_eq!(dest_len, yes_len);
+                assert_eq!(dest_len, no_len);
+
+                for i in 0..dest_len {
+                    let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
+                    let yes = this.read_immediate(&this.mplace_index(&yes, i)?.into())?;
+                    let no = this.read_immediate(&this.mplace_index(&no, i)?.into())?;
+                    let dest = this.mplace_index(&dest, i)?;
+
+                    let val = if simd_element_to_bool(mask)? { yes } else { no };
+                    this.write_immediate(*val, &dest.into())?;
+                }
+            }
+            "select_bitmask" => {
+                let [mask, yes, no] = check_arg_count(args)?;
+                let (yes, yes_len) = this.operand_to_simd(yes)?;
+                let (no, no_len) = this.operand_to_simd(no)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+                let bitmask_len = dest_len.max(8);
+
+                assert!(mask.layout.ty.is_integral());
+                assert!(bitmask_len <= 64);
+                assert_eq!(bitmask_len, mask.layout.size.bits());
+                assert_eq!(dest_len, yes_len);
+                assert_eq!(dest_len, no_len);
+                let dest_len = u32::try_from(dest_len).unwrap();
+                let bitmask_len = u32::try_from(bitmask_len).unwrap();
+
+                let mask: u64 =
+                    this.read_scalar(mask)?.to_bits(mask.layout.size)?.try_into().unwrap();
+                for i in 0..dest_len {
+                    let mask = mask
+                        & 1u64
+                            .checked_shl(simd_bitmask_index(i, dest_len, this.data_layout().endian))
+                            .unwrap();
+                    let yes = this.read_immediate(&this.mplace_index(&yes, i.into())?.into())?;
+                    let no = this.read_immediate(&this.mplace_index(&no, i.into())?.into())?;
+                    let dest = this.mplace_index(&dest, i.into())?;
+
+                    let val = if mask != 0 { yes } else { no };
+                    this.write_immediate(*val, &dest.into())?;
+                }
+                for i in dest_len..bitmask_len {
+                    // If the mask is "padded", ensure that padding is all-zero.
+                    let mask = mask & 1u64.checked_shl(i).unwrap();
+                    if mask != 0 {
+                        throw_ub_format!(
+                            "a SIMD bitmask less than 8 bits long must be filled with 0s for the remaining bits"
+                        );
+                    }
+                }
+            }
+            #[rustfmt::skip]
+            "cast" | "as" => {
+                let [op] = check_arg_count(args)?;
+                let (op, op_len) = this.operand_to_simd(op)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                assert_eq!(dest_len, op_len);
+
+                let safe_cast = intrinsic_name == "as";
+
+                for i in 0..dest_len {
+                    let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
+                    let dest = this.mplace_index(&dest, i)?;
+
+                    let val = match (op.layout.ty.kind(), dest.layout.ty.kind()) {
+                        // Int-to-(int|float): always safe
+                        (ty::Int(_) | ty::Uint(_), ty::Int(_) | ty::Uint(_) | ty::Float(_)) =>
+                            this.misc_cast(&op, dest.layout.ty)?,
+                        // Float-to-float: always safe
+                        (ty::Float(_), ty::Float(_)) =>
+                            this.misc_cast(&op, dest.layout.ty)?,
+                        // Float-to-int in safe mode
+                        (ty::Float(_), ty::Int(_) | ty::Uint(_)) if safe_cast =>
+                            this.misc_cast(&op, dest.layout.ty)?,
+                        // Float-to-int in unchecked mode
+                        (ty::Float(FloatTy::F32), ty::Int(_) | ty::Uint(_)) if !safe_cast =>
+                            this.float_to_int_unchecked(op.to_scalar().to_f32()?, dest.layout.ty)?.into(),
+                        (ty::Float(FloatTy::F64), ty::Int(_) | ty::Uint(_)) if !safe_cast =>
+                            this.float_to_int_unchecked(op.to_scalar().to_f64()?, dest.layout.ty)?.into(),
+                        _ =>
+                            throw_unsup_format!(
+                                "Unsupported SIMD cast from element type {from_ty} to {to_ty}",
+                                from_ty = op.layout.ty,
+                                to_ty = dest.layout.ty,
+                            ),
+                    };
+                    this.write_immediate(val, &dest.into())?;
+                }
+            }
+            "shuffle" => {
+                let [left, right, index] = check_arg_count(args)?;
+                let (left, left_len) = this.operand_to_simd(left)?;
+                let (right, right_len) = this.operand_to_simd(right)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                // `index` is an array, not a SIMD type
+                let ty::Array(_, index_len) = index.layout.ty.kind() else {
+                    span_bug!(this.cur_span(), "simd_shuffle index argument has non-array type {}", index.layout.ty)
+                };
+                let index_len = index_len.eval_usize(*this.tcx, this.param_env());
+
+                assert_eq!(left_len, right_len);
+                assert_eq!(index_len, dest_len);
+
+                for i in 0..dest_len {
+                    let src_index: u64 = this
+                        .read_immediate(&this.operand_index(index, i)?)?
+                        .to_scalar()
+                        .to_u32()?
+                        .into();
+                    let dest = this.mplace_index(&dest, i)?;
+
+                    let val = if src_index < left_len {
+                        this.read_immediate(&this.mplace_index(&left, src_index)?.into())?
+                    } else if src_index < left_len.checked_add(right_len).unwrap() {
+                        let right_idx = src_index.checked_sub(left_len).unwrap();
+                        this.read_immediate(&this.mplace_index(&right, right_idx)?.into())?
+                    } else {
+                        span_bug!(
+                            this.cur_span(),
+                            "simd_shuffle index {src_index} is out of bounds for 2 vectors of size {left_len}",
+                        );
+                    };
+                    this.write_immediate(*val, &dest.into())?;
+                }
+            }
+            "gather" => {
+                let [passthru, ptrs, mask] = check_arg_count(args)?;
+                let (passthru, passthru_len) = this.operand_to_simd(passthru)?;
+                let (ptrs, ptrs_len) = this.operand_to_simd(ptrs)?;
+                let (mask, mask_len) = this.operand_to_simd(mask)?;
+                let (dest, dest_len) = this.place_to_simd(dest)?;
+
+                assert_eq!(dest_len, passthru_len);
+                assert_eq!(dest_len, ptrs_len);
+                assert_eq!(dest_len, mask_len);
+
+                for i in 0..dest_len {
+                    let passthru = this.read_immediate(&this.mplace_index(&passthru, i)?.into())?;
+                    let ptr = this.read_immediate(&this.mplace_index(&ptrs, i)?.into())?;
+                    let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
+                    let dest = this.mplace_index(&dest, i)?;
+
+                    let val = if simd_element_to_bool(mask)? {
+                        let place = this.deref_operand(&ptr.into())?;
+                        this.read_immediate(&place.into())?
+                    } else {
+                        passthru
+                    };
+                    this.write_immediate(*val, &dest.into())?;
+                }
+            }
+            "scatter" => {
+                let [value, ptrs, mask] = check_arg_count(args)?;
+                let (value, value_len) = this.operand_to_simd(value)?;
+                let (ptrs, ptrs_len) = this.operand_to_simd(ptrs)?;
+                let (mask, mask_len) = this.operand_to_simd(mask)?;
+
+                assert_eq!(ptrs_len, value_len);
+                assert_eq!(ptrs_len, mask_len);
+
+                for i in 0..ptrs_len {
+                    let value = this.read_immediate(&this.mplace_index(&value, i)?.into())?;
+                    let ptr = this.read_immediate(&this.mplace_index(&ptrs, i)?.into())?;
+                    let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
+
+                    if simd_element_to_bool(mask)? {
+                        let place = this.deref_operand(&ptr.into())?;
+                        this.write_immediate(*value, &place.into())?;
+                    }
+                }
+            }
+            "bitmask" => {
+                let [op] = check_arg_count(args)?;
+                let (op, op_len) = this.operand_to_simd(op)?;
+                let bitmask_len = op_len.max(8);
+
+                assert!(dest.layout.ty.is_integral());
+                assert!(bitmask_len <= 64);
+                assert_eq!(bitmask_len, dest.layout.size.bits());
+                let op_len = u32::try_from(op_len).unwrap();
+
+                let mut res = 0u64;
+                for i in 0..op_len {
+                    let op = this.read_immediate(&this.mplace_index(&op, i.into())?.into())?;
+                    if simd_element_to_bool(op)? {
+                        res |= 1u64
+                            .checked_shl(simd_bitmask_index(i, op_len, this.data_layout().endian))
+                            .unwrap();
+                    }
+                }
+                this.write_int(res, dest)?;
+            }
+
+            name => throw_unsup_format!("unimplemented intrinsic: `simd_{name}`"),
+        }
+        Ok(())
+    }
+}
+
+fn bool_to_simd_element(b: bool, size: Size) -> Scalar<Provenance> {
+    // SIMD uses all-1 as pattern for "true"
+    let val = if b { -1 } else { 0 };
+    Scalar::from_int(val, size)
+}
+
+fn simd_element_to_bool(elem: ImmTy<'_, Provenance>) -> InterpResult<'_, bool> {
+    let val = elem.to_scalar().to_int(elem.layout.size)?;
+    Ok(match val {
+        0 => false,
+        -1 => true,
+        _ => throw_ub_format!("each element of a SIMD mask must be all-0-bits or all-1-bits"),
+    })
+}
+
+fn simd_bitmask_index(idx: u32, vec_len: u32, endianess: Endian) -> u32 {
+    assert!(idx < vec_len);
+    match endianess {
+        Endian::Little => idx,
+        #[allow(clippy::integer_arithmetic)] // idx < vec_len
+        Endian::Big => vec_len - 1 - idx, // reverse order of bits
+    }
+}
+
+fn fmax_op<'tcx>(
+    left: &ImmTy<'tcx, Provenance>,
+    right: &ImmTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    assert_eq!(left.layout.ty, right.layout.ty);
+    let ty::Float(float_ty) = left.layout.ty.kind() else {
+        bug!("fmax operand is not a float")
+    };
+    let left = left.to_scalar();
+    let right = right.to_scalar();
+    Ok(match float_ty {
+        FloatTy::F32 => Scalar::from_f32(left.to_f32()?.max(right.to_f32()?)),
+        FloatTy::F64 => Scalar::from_f64(left.to_f64()?.max(right.to_f64()?)),
+    })
+}
+
+fn fmin_op<'tcx>(
+    left: &ImmTy<'tcx, Provenance>,
+    right: &ImmTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    assert_eq!(left.layout.ty, right.layout.ty);
+    let ty::Float(float_ty) = left.layout.ty.kind() else {
+        bug!("fmin operand is not a float")
+    };
+    let left = left.to_scalar();
+    let right = right.to_scalar();
+    Ok(match float_ty {
+        FloatTy::F32 => Scalar::from_f32(left.to_f32()?.min(right.to_f32()?)),
+        FloatTy::F64 => Scalar::from_f64(left.to_f64()?.min(right.to_f64()?)),
+    })
+}
diff --git a/src/tools/miri/src/shims/mod.rs b/src/tools/miri/src/shims/mod.rs
new file mode 100644
index 000000000000..8cb648e51732
--- /dev/null
+++ b/src/tools/miri/src/shims/mod.rs
@@ -0,0 +1,107 @@
+#![warn(clippy::integer_arithmetic)]
+
+mod backtrace;
+#[cfg(unix)]
+pub mod ffi_support;
+pub mod foreign_items;
+pub mod intrinsics;
+pub mod unix;
+pub mod windows;
+
+pub mod dlsym;
+pub mod env;
+pub mod os_str;
+pub mod panic;
+pub mod time;
+pub mod tls;
+
+// End module management, begin local code
+
+use log::trace;
+
+use rustc_middle::{mir, ty};
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use helpers::check_arg_count;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn find_mir_or_eval_fn(
+        &mut self,
+        instance: ty::Instance<'tcx>,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx, Option<(&'mir mir::Body<'tcx>, ty::Instance<'tcx>)>> {
+        let this = self.eval_context_mut();
+        trace!("eval_fn_call: {:#?}, {:?}", instance, dest);
+
+        // There are some more lang items we want to hook that CTFE does not hook (yet).
+        if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
+            let [ptr, align] = check_arg_count(args)?;
+            if this.align_offset(ptr, align, dest, ret, unwind)? {
+                return Ok(None);
+            }
+        }
+
+        // Try to see if we can do something about foreign items.
+        if this.tcx.is_foreign_item(instance.def_id()) {
+            // An external function call that does not have a MIR body. We either find MIR elsewhere
+            // or emulate its effect.
+            // This will be Ok(None) if we're emulating the intrinsic entirely within Miri (no need
+            // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
+            // foreign function
+            // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
+            return this.emulate_foreign_item(instance.def_id(), abi, args, dest, ret, unwind);
+        }
+
+        // Otherwise, load the MIR.
+        Ok(Some((this.load_mir(instance.def, None)?, instance)))
+    }
+
+    /// Returns `true` if the computation was performed, and `false` if we should just evaluate
+    /// the actual MIR of `align_offset`.
+    fn align_offset(
+        &mut self,
+        ptr_op: &OpTy<'tcx, Provenance>,
+        align_op: &OpTy<'tcx, Provenance>,
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx, bool> {
+        let this = self.eval_context_mut();
+        let ret = ret.unwrap();
+
+        if this.machine.check_alignment != AlignmentCheck::Symbolic {
+            // Just use actual implementation.
+            return Ok(false);
+        }
+
+        let req_align = this.read_scalar(align_op)?.to_machine_usize(this)?;
+
+        // Stop if the alignment is not a power of two.
+        if !req_align.is_power_of_two() {
+            this.start_panic("align_offset: align is not a power-of-two", unwind)?;
+            return Ok(true); // nothing left to do
+        }
+
+        let ptr = this.read_pointer(ptr_op)?;
+        if let Ok((alloc_id, _offset, _)) = this.ptr_try_get_alloc_id(ptr) {
+            // Only do anything if we can identify the allocation this goes to.
+            let (_size, cur_align, _kind) = this.get_alloc_info(alloc_id);
+            if cur_align.bytes() >= req_align {
+                // If the allocation alignment is at least the required alignment we use the
+                // real implementation.
+                return Ok(false);
+            }
+        }
+
+        // Return error result (usize::MAX), and jump to caller.
+        this.write_scalar(Scalar::from_machine_usize(this.machine_usize_max(), this), dest)?;
+        this.go_to_block(ret);
+        Ok(true)
+    }
+}
diff --git a/src/tools/miri/src/shims/os_str.rs b/src/tools/miri/src/shims/os_str.rs
new file mode 100644
index 000000000000..407dab970ad7
--- /dev/null
+++ b/src/tools/miri/src/shims/os_str.rs
@@ -0,0 +1,308 @@
+use std::borrow::Cow;
+use std::ffi::{OsStr, OsString};
+use std::iter;
+use std::path::{Path, PathBuf};
+
+#[cfg(unix)]
+use std::os::unix::ffi::{OsStrExt, OsStringExt};
+#[cfg(windows)]
+use std::os::windows::ffi::{OsStrExt, OsStringExt};
+
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_target::abi::{Align, Size};
+
+use crate::*;
+
+/// Represent how path separator conversion should be done.
+pub enum PathConversion {
+    HostToTarget,
+    TargetToHost,
+}
+
+#[cfg(unix)]
+pub fn os_str_to_bytes<'a, 'tcx>(os_str: &'a OsStr) -> InterpResult<'tcx, &'a [u8]> {
+    Ok(os_str.as_bytes())
+}
+
+#[cfg(not(unix))]
+pub fn os_str_to_bytes<'a, 'tcx>(os_str: &'a OsStr) -> InterpResult<'tcx, &'a [u8]> {
+    // On non-unix platforms the best we can do to transform bytes from/to OS strings is to do the
+    // intermediate transformation into strings. Which invalidates non-utf8 paths that are actually
+    // valid.
+    os_str
+        .to_str()
+        .map(|s| s.as_bytes())
+        .ok_or_else(|| err_unsup_format!("{:?} is not a valid utf-8 string", os_str).into())
+}
+
+#[cfg(unix)]
+pub fn bytes_to_os_str<'a, 'tcx>(bytes: &'a [u8]) -> InterpResult<'tcx, &'a OsStr> {
+    Ok(OsStr::from_bytes(bytes))
+}
+#[cfg(not(unix))]
+pub fn bytes_to_os_str<'a, 'tcx>(bytes: &'a [u8]) -> InterpResult<'tcx, &'a OsStr> {
+    let s = std::str::from_utf8(bytes)
+        .map_err(|_| err_unsup_format!("{:?} is not a valid utf-8 string", bytes))?;
+    Ok(OsStr::new(s))
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Helper function to read an OsString from a null-terminated sequence of bytes, which is what
+    /// the Unix APIs usually handle.
+    fn read_os_str_from_c_str<'a>(
+        &'a self,
+        ptr: Pointer<Option<Provenance>>,
+    ) -> InterpResult<'tcx, &'a OsStr>
+    where
+        'tcx: 'a,
+        'mir: 'a,
+    {
+        let this = self.eval_context_ref();
+        let bytes = this.read_c_str(ptr)?;
+        bytes_to_os_str(bytes)
+    }
+
+    /// Helper function to read an OsString from a 0x0000-terminated sequence of u16,
+    /// which is what the Windows APIs usually handle.
+    fn read_os_str_from_wide_str<'a>(
+        &'a self,
+        ptr: Pointer<Option<Provenance>>,
+    ) -> InterpResult<'tcx, OsString>
+    where
+        'tcx: 'a,
+        'mir: 'a,
+    {
+        #[cfg(windows)]
+        pub fn u16vec_to_osstring<'tcx>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
+            Ok(OsString::from_wide(&u16_vec[..]))
+        }
+        #[cfg(not(windows))]
+        pub fn u16vec_to_osstring<'tcx>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
+            let s = String::from_utf16(&u16_vec[..])
+                .map_err(|_| err_unsup_format!("{:?} is not a valid utf-16 string", u16_vec))?;
+            Ok(s.into())
+        }
+
+        let u16_vec = self.eval_context_ref().read_wide_str(ptr)?;
+        u16vec_to_osstring(u16_vec)
+    }
+
+    /// Helper function to write an OsStr as a null-terminated sequence of bytes, which is what
+    /// the Unix APIs usually handle. This function returns `Ok((false, length))` without trying
+    /// to write if `size` is not large enough to fit the contents of `os_string` plus a null
+    /// terminator. It returns `Ok((true, length))` if the writing process was successful. The
+    /// string length returned does include the null terminator.
+    fn write_os_str_to_c_str(
+        &mut self,
+        os_str: &OsStr,
+        ptr: Pointer<Option<Provenance>>,
+        size: u64,
+    ) -> InterpResult<'tcx, (bool, u64)> {
+        let bytes = os_str_to_bytes(os_str)?;
+        // If `size` is smaller or equal than `bytes.len()`, writing `bytes` plus the required null
+        // terminator to memory using the `ptr` pointer would cause an out-of-bounds access.
+        let string_length = u64::try_from(bytes.len()).unwrap();
+        let string_length = string_length.checked_add(1).unwrap();
+        if size < string_length {
+            return Ok((false, string_length));
+        }
+        self.eval_context_mut()
+            .write_bytes_ptr(ptr, bytes.iter().copied().chain(iter::once(0u8)))?;
+        Ok((true, string_length))
+    }
+
+    /// Helper function to write an OsStr as a 0x0000-terminated u16-sequence, which is what
+    /// the Windows APIs usually handle. This function returns `Ok((false, length))` without trying
+    /// to write if `size` is not large enough to fit the contents of `os_string` plus a null
+    /// terminator. It returns `Ok((true, length))` if the writing process was successful. The
+    /// string length returned does include the null terminator. Length is measured in units of
+    /// `u16.`
+    fn write_os_str_to_wide_str(
+        &mut self,
+        os_str: &OsStr,
+        ptr: Pointer<Option<Provenance>>,
+        size: u64,
+    ) -> InterpResult<'tcx, (bool, u64)> {
+        #[cfg(windows)]
+        fn os_str_to_u16vec<'tcx>(os_str: &OsStr) -> InterpResult<'tcx, Vec<u16>> {
+            Ok(os_str.encode_wide().collect())
+        }
+        #[cfg(not(windows))]
+        fn os_str_to_u16vec<'tcx>(os_str: &OsStr) -> InterpResult<'tcx, Vec<u16>> {
+            // On non-Windows platforms the best we can do to transform Vec<u16> from/to OS strings is to do the
+            // intermediate transformation into strings. Which invalidates non-utf8 paths that are actually
+            // valid.
+            os_str
+                .to_str()
+                .map(|s| s.encode_utf16().collect())
+                .ok_or_else(|| err_unsup_format!("{:?} is not a valid utf-8 string", os_str).into())
+        }
+
+        let u16_vec = os_str_to_u16vec(os_str)?;
+        // If `size` is smaller or equal than `bytes.len()`, writing `bytes` plus the required
+        // 0x0000 terminator to memory would cause an out-of-bounds access.
+        let string_length = u64::try_from(u16_vec.len()).unwrap();
+        let string_length = string_length.checked_add(1).unwrap();
+        if size < string_length {
+            return Ok((false, string_length));
+        }
+
+        // Store the UTF-16 string.
+        let size2 = Size::from_bytes(2);
+        let this = self.eval_context_mut();
+        let mut alloc = this
+            .get_ptr_alloc_mut(ptr, size2 * string_length, Align::from_bytes(2).unwrap())?
+            .unwrap(); // not a ZST, so we will get a result
+        for (offset, wchar) in u16_vec.into_iter().chain(iter::once(0x0000)).enumerate() {
+            let offset = u64::try_from(offset).unwrap();
+            alloc.write_scalar(alloc_range(size2 * offset, size2), Scalar::from_u16(wchar))?;
+        }
+        Ok((true, string_length))
+    }
+
+    /// Allocate enough memory to store the given `OsStr` as a null-terminated sequence of bytes.
+    fn alloc_os_str_as_c_str(
+        &mut self,
+        os_str: &OsStr,
+        memkind: MemoryKind<MiriMemoryKind>,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let size = u64::try_from(os_str.len()).unwrap().checked_add(1).unwrap(); // Make space for `0` terminator.
+        let this = self.eval_context_mut();
+
+        let arg_type = this.tcx.mk_array(this.tcx.types.u8, size);
+        let arg_place = this.allocate(this.layout_of(arg_type).unwrap(), memkind)?;
+        assert!(self.write_os_str_to_c_str(os_str, arg_place.ptr, size).unwrap().0);
+        Ok(arg_place.ptr)
+    }
+
+    /// Allocate enough memory to store the given `OsStr` as a null-terminated sequence of `u16`.
+    fn alloc_os_str_as_wide_str(
+        &mut self,
+        os_str: &OsStr,
+        memkind: MemoryKind<MiriMemoryKind>,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let size = u64::try_from(os_str.len()).unwrap().checked_add(1).unwrap(); // Make space for `0x0000` terminator.
+        let this = self.eval_context_mut();
+
+        let arg_type = this.tcx.mk_array(this.tcx.types.u16, size);
+        let arg_place = this.allocate(this.layout_of(arg_type).unwrap(), memkind)?;
+        assert!(self.write_os_str_to_wide_str(os_str, arg_place.ptr, size).unwrap().0);
+        Ok(arg_place.ptr)
+    }
+
+    /// Read a null-terminated sequence of bytes, and perform path separator conversion if needed.
+    fn read_path_from_c_str<'a>(
+        &'a self,
+        ptr: Pointer<Option<Provenance>>,
+    ) -> InterpResult<'tcx, Cow<'a, Path>>
+    where
+        'tcx: 'a,
+        'mir: 'a,
+    {
+        let this = self.eval_context_ref();
+        let os_str = this.read_os_str_from_c_str(ptr)?;
+
+        Ok(match this.convert_path_separator(Cow::Borrowed(os_str), PathConversion::TargetToHost) {
+            Cow::Borrowed(x) => Cow::Borrowed(Path::new(x)),
+            Cow::Owned(y) => Cow::Owned(PathBuf::from(y)),
+        })
+    }
+
+    /// Read a null-terminated sequence of `u16`s, and perform path separator conversion if needed.
+    fn read_path_from_wide_str(
+        &self,
+        ptr: Pointer<Option<Provenance>>,
+    ) -> InterpResult<'tcx, PathBuf> {
+        let this = self.eval_context_ref();
+        let os_str = this.read_os_str_from_wide_str(ptr)?;
+
+        Ok(this
+            .convert_path_separator(Cow::Owned(os_str), PathConversion::TargetToHost)
+            .into_owned()
+            .into())
+    }
+
+    /// Write a Path to the machine memory (as a null-terminated sequence of bytes),
+    /// adjusting path separators if needed.
+    fn write_path_to_c_str(
+        &mut self,
+        path: &Path,
+        ptr: Pointer<Option<Provenance>>,
+        size: u64,
+    ) -> InterpResult<'tcx, (bool, u64)> {
+        let this = self.eval_context_mut();
+        let os_str = this
+            .convert_path_separator(Cow::Borrowed(path.as_os_str()), PathConversion::HostToTarget);
+        this.write_os_str_to_c_str(&os_str, ptr, size)
+    }
+
+    /// Write a Path to the machine memory (as a null-terminated sequence of `u16`s),
+    /// adjusting path separators if needed.
+    fn write_path_to_wide_str(
+        &mut self,
+        path: &Path,
+        ptr: Pointer<Option<Provenance>>,
+        size: u64,
+    ) -> InterpResult<'tcx, (bool, u64)> {
+        let this = self.eval_context_mut();
+        let os_str = this
+            .convert_path_separator(Cow::Borrowed(path.as_os_str()), PathConversion::HostToTarget);
+        this.write_os_str_to_wide_str(&os_str, ptr, size)
+    }
+
+    /// Allocate enough memory to store a Path as a null-terminated sequence of bytes,
+    /// adjusting path separators if needed.
+    fn alloc_path_as_c_str(
+        &mut self,
+        path: &Path,
+        memkind: MemoryKind<MiriMemoryKind>,
+    ) -> InterpResult<'tcx, Pointer<Option<Provenance>>> {
+        let this = self.eval_context_mut();
+        let os_str = this
+            .convert_path_separator(Cow::Borrowed(path.as_os_str()), PathConversion::HostToTarget);
+        this.alloc_os_str_as_c_str(&os_str, memkind)
+    }
+
+    fn convert_path_separator<'a>(
+        &self,
+        os_str: Cow<'a, OsStr>,
+        direction: PathConversion,
+    ) -> Cow<'a, OsStr> {
+        let this = self.eval_context_ref();
+        let target_os = &this.tcx.sess.target.os;
+        #[cfg(windows)]
+        return if target_os == "windows" {
+            // Windows-on-Windows, all fine.
+            os_str
+        } else {
+            // Unix target, Windows host.
+            let (from, to) = match direction {
+                PathConversion::HostToTarget => ('\\', '/'),
+                PathConversion::TargetToHost => ('/', '\\'),
+            };
+            let converted = os_str
+                .encode_wide()
+                .map(|wchar| if wchar == from as u16 { to as u16 } else { wchar })
+                .collect::<Vec<_>>();
+            Cow::Owned(OsString::from_wide(&converted))
+        };
+        #[cfg(unix)]
+        return if target_os == "windows" {
+            // Windows target, Unix host.
+            let (from, to) = match direction {
+                PathConversion::HostToTarget => ('/', '\\'),
+                PathConversion::TargetToHost => ('\\', '/'),
+            };
+            let converted = os_str
+                .as_bytes()
+                .iter()
+                .map(|&wchar| if wchar == from as u8 { to as u8 } else { wchar })
+                .collect::<Vec<_>>();
+            Cow::Owned(OsString::from_vec(converted))
+        } else {
+            // Unix-on-Unix, all is fine.
+            os_str
+        };
+    }
+}
diff --git a/src/tools/miri/src/shims/panic.rs b/src/tools/miri/src/shims/panic.rs
new file mode 100644
index 000000000000..2e8245acf4a6
--- /dev/null
+++ b/src/tools/miri/src/shims/panic.rs
@@ -0,0 +1,227 @@
+//! Panic runtime for Miri.
+//!
+//! The core pieces of the runtime are:
+//! - An implementation of `__rust_maybe_catch_panic` that pushes the invoked stack frame with
+//!   some extra metadata derived from the panic-catching arguments of `__rust_maybe_catch_panic`.
+//! - A hack in `libpanic_unwind` that calls the `miri_start_panic` intrinsic instead of the
+//!   target-native panic runtime. (This lives in the rustc repo.)
+//! - An implementation of `miri_start_panic` that stores its argument (the panic payload), and then
+//!   immediately returns, but on the *unwind* edge (not the normal return edge), thus initiating unwinding.
+//! - A hook executed each time a frame is popped, such that if the frame pushed by `__rust_maybe_catch_panic`
+//!   gets popped *during unwinding*, we take the panic payload and store it according to the extra
+//!   metadata we remembered when pushing said frame.
+
+use log::trace;
+
+use rustc_ast::Mutability;
+use rustc_middle::{mir, ty};
+use rustc_span::Symbol;
+use rustc_target::spec::abi::Abi;
+use rustc_target::spec::PanicStrategy;
+
+use crate::*;
+use helpers::check_arg_count;
+
+/// Holds all of the relevant data for when unwinding hits a `try` frame.
+#[derive(Debug)]
+pub struct CatchUnwindData<'tcx> {
+    /// The `catch_fn` callback to call in case of a panic.
+    catch_fn: Pointer<Option<Provenance>>,
+    /// The `data` argument for that callback.
+    data: Scalar<Provenance>,
+    /// The return place from the original call to `try`.
+    dest: PlaceTy<'tcx, Provenance>,
+    /// The return block from the original call to `try`.
+    ret: mir::BasicBlock,
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Handles the special `miri_start_panic` intrinsic, which is called
+    /// by libpanic_unwind to delegate the actual unwinding process to Miri.
+    fn handle_miri_start_panic(
+        &mut self,
+        abi: Abi,
+        link_name: Symbol,
+        args: &[OpTy<'tcx, Provenance>],
+        unwind: StackPopUnwind,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        trace!("miri_start_panic: {:?}", this.frame().instance);
+
+        // Get the raw pointer stored in arg[0] (the panic payload).
+        let [payload] = this.check_shim(abi, Abi::Rust, link_name, args)?;
+        let payload = this.read_scalar(payload)?;
+        let thread = this.active_thread_mut();
+        assert!(thread.panic_payload.is_none(), "the panic runtime should avoid double-panics");
+        thread.panic_payload = Some(payload);
+
+        // Jump to the unwind block to begin unwinding.
+        this.unwind_to_block(unwind)?;
+        Ok(())
+    }
+
+    /// Handles the `try` intrinsic, the underlying implementation of `std::panicking::try`.
+    fn handle_try(
+        &mut self,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: mir::BasicBlock,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        // Signature:
+        //   fn r#try(try_fn: fn(*mut u8), data: *mut u8, catch_fn: fn(*mut u8, *mut u8)) -> i32
+        // Calls `try_fn` with `data` as argument. If that executes normally, returns 0.
+        // If that unwinds, calls `catch_fn` with the first argument being `data` and
+        // then second argument being a target-dependent `payload` (i.e. it is up to us to define
+        // what that is), and returns 1.
+        // The `payload` is passed (by libstd) to `__rust_panic_cleanup`, which is then expected to
+        // return a `Box<dyn Any + Send + 'static>`.
+        // In Miri, `miri_start_panic` is passed exactly that type, so we make the `payload` simply
+        // a pointer to `Box<dyn Any + Send + 'static>`.
+
+        // Get all the arguments.
+        let [try_fn, data, catch_fn] = check_arg_count(args)?;
+        let try_fn = this.read_pointer(try_fn)?;
+        let data = this.read_scalar(data)?;
+        let catch_fn = this.read_pointer(catch_fn)?;
+
+        // Now we make a function call, and pass `data` as first and only argument.
+        let f_instance = this.get_ptr_fn(try_fn)?.as_instance()?;
+        trace!("try_fn: {:?}", f_instance);
+        this.call_function(
+            f_instance,
+            Abi::Rust,
+            &[data.into()],
+            None,
+            // Directly return to caller.
+            StackPopCleanup::Goto { ret: Some(ret), unwind: StackPopUnwind::Skip },
+        )?;
+
+        // We ourselves will return `0`, eventually (will be overwritten if we catch a panic).
+        this.write_null(dest)?;
+
+        // In unwind mode, we tag this frame with the extra data needed to catch unwinding.
+        // This lets `handle_stack_pop` (below) know that we should stop unwinding
+        // when we pop this frame.
+        if this.tcx.sess.panic_strategy() == PanicStrategy::Unwind {
+            this.frame_mut().extra.catch_unwind =
+                Some(CatchUnwindData { catch_fn, data, dest: dest.clone(), ret });
+        }
+
+        Ok(())
+    }
+
+    fn handle_stack_pop_unwind(
+        &mut self,
+        mut extra: FrameData<'tcx>,
+        unwinding: bool,
+    ) -> InterpResult<'tcx, StackPopJump> {
+        let this = self.eval_context_mut();
+        trace!("handle_stack_pop_unwind(extra = {:?}, unwinding = {})", extra, unwinding);
+
+        // We only care about `catch_panic` if we're unwinding - if we're doing a normal
+        // return, then we don't need to do anything special.
+        if let (true, Some(catch_unwind)) = (unwinding, extra.catch_unwind.take()) {
+            // We've just popped a frame that was pushed by `try`,
+            // and we are unwinding, so we should catch that.
+            trace!(
+                "unwinding: found catch_panic frame during unwinding: {:?}",
+                this.frame().instance
+            );
+
+            // We set the return value of `try` to 1, since there was a panic.
+            this.write_scalar(Scalar::from_i32(1), &catch_unwind.dest)?;
+
+            // The Thread's `panic_payload` holds what was passed to `miri_start_panic`.
+            // This is exactly the second argument we need to pass to `catch_fn`.
+            let payload = this.active_thread_mut().panic_payload.take().unwrap();
+
+            // Push the `catch_fn` stackframe.
+            let f_instance = this.get_ptr_fn(catch_unwind.catch_fn)?.as_instance()?;
+            trace!("catch_fn: {:?}", f_instance);
+            this.call_function(
+                f_instance,
+                Abi::Rust,
+                &[catch_unwind.data.into(), payload.into()],
+                None,
+                // Directly return to caller of `try`.
+                StackPopCleanup::Goto { ret: Some(catch_unwind.ret), unwind: StackPopUnwind::Skip },
+            )?;
+
+            // We pushed a new stack frame, the engine should not do any jumping now!
+            Ok(StackPopJump::NoJump)
+        } else {
+            Ok(StackPopJump::Normal)
+        }
+    }
+
+    /// Start a panic in the interpreter with the given message as payload.
+    fn start_panic(&mut self, msg: &str, unwind: StackPopUnwind) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        // First arg: message.
+        let msg = this.allocate_str(msg, MiriMemoryKind::Machine.into(), Mutability::Not);
+
+        // Call the lang item.
+        let panic = this.tcx.lang_items().panic_fn().unwrap();
+        let panic = ty::Instance::mono(this.tcx.tcx, panic);
+        this.call_function(
+            panic,
+            Abi::Rust,
+            &[msg.to_ref(this)],
+            None,
+            StackPopCleanup::Goto { ret: None, unwind },
+        )
+    }
+
+    fn assert_panic(
+        &mut self,
+        msg: &mir::AssertMessage<'tcx>,
+        unwind: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        use rustc_middle::mir::AssertKind::*;
+        let this = self.eval_context_mut();
+
+        match msg {
+            BoundsCheck { index, len } => {
+                // Forward to `panic_bounds_check` lang item.
+
+                // First arg: index.
+                let index = this.read_scalar(&this.eval_operand(index, None)?)?;
+                // Second arg: len.
+                let len = this.read_scalar(&this.eval_operand(len, None)?)?;
+
+                // Call the lang item.
+                let panic_bounds_check = this.tcx.lang_items().panic_bounds_check_fn().unwrap();
+                let panic_bounds_check = ty::Instance::mono(this.tcx.tcx, panic_bounds_check);
+                this.call_function(
+                    panic_bounds_check,
+                    Abi::Rust,
+                    &[index.into(), len.into()],
+                    None,
+                    StackPopCleanup::Goto {
+                        ret: None,
+                        unwind: match unwind {
+                            Some(cleanup) => StackPopUnwind::Cleanup(cleanup),
+                            None => StackPopUnwind::Skip,
+                        },
+                    },
+                )?;
+            }
+            _ => {
+                // Forward everything else to `panic` lang item.
+                this.start_panic(
+                    msg.description(),
+                    match unwind {
+                        Some(cleanup) => StackPopUnwind::Cleanup(cleanup),
+                        None => StackPopUnwind::Skip,
+                    },
+                )?;
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/time.rs b/src/tools/miri/src/shims/time.rs
new file mode 100644
index 000000000000..24fe52453939
--- /dev/null
+++ b/src/tools/miri/src/shims/time.rs
@@ -0,0 +1,255 @@
+use std::time::{Duration, SystemTime};
+
+use crate::*;
+
+/// Returns the time elapsed between the provided time and the unix epoch as a `Duration`.
+pub fn system_time_to_duration<'tcx>(time: &SystemTime) -> InterpResult<'tcx, Duration> {
+    time.duration_since(SystemTime::UNIX_EPOCH)
+        .map_err(|_| err_unsup_format!("times before the Unix epoch are not supported").into())
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn clock_gettime(
+        &mut self,
+        clk_id_op: &OpTy<'tcx, Provenance>,
+        tp_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        // This clock support is deliberately minimal because a lot of clock types have fiddly
+        // properties (is it possible for Miri to be suspended independently of the host?). If you
+        // have a use for another clock type, please open an issue.
+
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("linux", "clock_gettime");
+
+        let clk_id = this.read_scalar(clk_id_op)?.to_i32()?;
+
+        // Linux has two main kinds of clocks. REALTIME clocks return the actual time since the
+        // Unix epoch, including effects which may cause time to move backwards such as NTP.
+        // Linux further distinguishes regular and "coarse" clocks, but the "coarse" version
+        // is just specified to be "faster and less precise", so we implement both the same way.
+        let absolute_clocks =
+            [this.eval_libc_i32("CLOCK_REALTIME")?, this.eval_libc_i32("CLOCK_REALTIME_COARSE")?];
+        // The second kind is MONOTONIC clocks for which 0 is an arbitrary time point, but they are
+        // never allowed to go backwards. We don't need to do any additonal monotonicity
+        // enforcement because std::time::Instant already guarantees that it is monotonic.
+        let relative_clocks =
+            [this.eval_libc_i32("CLOCK_MONOTONIC")?, this.eval_libc_i32("CLOCK_MONOTONIC_COARSE")?];
+
+        let duration = if absolute_clocks.contains(&clk_id) {
+            this.check_no_isolation("`clock_gettime` with `REALTIME` clocks")?;
+            system_time_to_duration(&SystemTime::now())?
+        } else if relative_clocks.contains(&clk_id) {
+            this.machine.clock.now().duration_since(this.machine.clock.anchor())
+        } else {
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            return Ok(Scalar::from_i32(-1));
+        };
+
+        let tv_sec = duration.as_secs();
+        let tv_nsec = duration.subsec_nanos();
+
+        this.write_int_fields(&[tv_sec.into(), tv_nsec.into()], &this.deref_operand(tp_op)?)?;
+
+        Ok(Scalar::from_i32(0))
+    }
+
+    fn gettimeofday(
+        &mut self,
+        tv_op: &OpTy<'tcx, Provenance>,
+        tz_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os_is_unix("gettimeofday");
+        this.check_no_isolation("`gettimeofday`")?;
+
+        // Using tz is obsolete and should always be null
+        let tz = this.read_pointer(tz_op)?;
+        if !this.ptr_is_null(tz)? {
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            return Ok(-1);
+        }
+
+        let duration = system_time_to_duration(&SystemTime::now())?;
+        let tv_sec = duration.as_secs();
+        let tv_usec = duration.subsec_micros();
+
+        this.write_int_fields(&[tv_sec.into(), tv_usec.into()], &this.deref_operand(tv_op)?)?;
+
+        Ok(0)
+    }
+
+    #[allow(non_snake_case, clippy::integer_arithmetic)]
+    fn GetSystemTimeAsFileTime(
+        &mut self,
+        LPFILETIME_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("windows", "GetSystemTimeAsFileTime");
+        this.check_no_isolation("`GetSystemTimeAsFileTime`")?;
+
+        let NANOS_PER_SEC = this.eval_windows_u64("time", "NANOS_PER_SEC")?;
+        let INTERVALS_PER_SEC = this.eval_windows_u64("time", "INTERVALS_PER_SEC")?;
+        let INTERVALS_TO_UNIX_EPOCH = this.eval_windows_u64("time", "INTERVALS_TO_UNIX_EPOCH")?;
+        let NANOS_PER_INTERVAL = NANOS_PER_SEC / INTERVALS_PER_SEC;
+        let SECONDS_TO_UNIX_EPOCH = INTERVALS_TO_UNIX_EPOCH / INTERVALS_PER_SEC;
+
+        let duration = system_time_to_duration(&SystemTime::now())?
+            + Duration::from_secs(SECONDS_TO_UNIX_EPOCH);
+        let duration_ticks = u64::try_from(duration.as_nanos() / u128::from(NANOS_PER_INTERVAL))
+            .map_err(|_| err_unsup_format!("programs running more than 2^64 Windows ticks after the Windows epoch are not supported"))?;
+
+        let dwLowDateTime = u32::try_from(duration_ticks & 0x00000000FFFFFFFF).unwrap();
+        let dwHighDateTime = u32::try_from((duration_ticks & 0xFFFFFFFF00000000) >> 32).unwrap();
+        this.write_int_fields(
+            &[dwLowDateTime.into(), dwHighDateTime.into()],
+            &this.deref_operand(LPFILETIME_op)?,
+        )?;
+
+        Ok(())
+    }
+
+    #[allow(non_snake_case)]
+    fn QueryPerformanceCounter(
+        &mut self,
+        lpPerformanceCount_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("windows", "QueryPerformanceCounter");
+
+        // QueryPerformanceCounter uses a hardware counter as its basis.
+        // Miri will emulate a counter with a resolution of 1 nanosecond.
+        let duration = this.machine.clock.now().duration_since(this.machine.clock.anchor());
+        let qpc = i64::try_from(duration.as_nanos()).map_err(|_| {
+            err_unsup_format!("programs running longer than 2^63 nanoseconds are not supported")
+        })?;
+        this.write_scalar(
+            Scalar::from_i64(qpc),
+            &this.deref_operand(lpPerformanceCount_op)?.into(),
+        )?;
+        Ok(-1) // return non-zero on success
+    }
+
+    #[allow(non_snake_case)]
+    fn QueryPerformanceFrequency(
+        &mut self,
+        lpFrequency_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("windows", "QueryPerformanceFrequency");
+
+        // Retrieves the frequency of the hardware performance counter.
+        // The frequency of the performance counter is fixed at system boot and
+        // is consistent across all processors.
+        // Miri emulates a "hardware" performance counter with a resolution of 1ns,
+        // and thus 10^9 counts per second.
+        this.write_scalar(
+            Scalar::from_i64(1_000_000_000),
+            &this.deref_operand(lpFrequency_op)?.into(),
+        )?;
+        Ok(-1) // Return non-zero on success
+    }
+
+    fn mach_absolute_time(&self) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_ref();
+
+        this.assert_target_os("macos", "mach_absolute_time");
+
+        // This returns a u64, with time units determined dynamically by `mach_timebase_info`.
+        // We return plain nanoseconds.
+        let duration = this.machine.clock.now().duration_since(this.machine.clock.anchor());
+        let res = u64::try_from(duration.as_nanos()).map_err(|_| {
+            err_unsup_format!("programs running longer than 2^64 nanoseconds are not supported")
+        })?;
+        Ok(Scalar::from_u64(res))
+    }
+
+    fn mach_timebase_info(
+        &mut self,
+        info_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("macos", "mach_timebase_info");
+
+        let info = this.deref_operand(info_op)?;
+
+        // Since our emulated ticks in `mach_absolute_time` *are* nanoseconds,
+        // no scaling needs to happen.
+        let (numer, denom) = (1, 1);
+        this.write_int_fields(&[numer.into(), denom.into()], &info)?;
+
+        Ok(Scalar::from_i32(0)) // KERN_SUCCESS
+    }
+
+    fn nanosleep(
+        &mut self,
+        req_op: &OpTy<'tcx, Provenance>,
+        _rem: &OpTy<'tcx, Provenance>, // Signal handlers are not supported, so rem will never be written to.
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os_is_unix("nanosleep");
+
+        let duration = match this.read_timespec(&this.deref_operand(req_op)?)? {
+            Some(duration) => duration,
+            None => {
+                let einval = this.eval_libc("EINVAL")?;
+                this.set_last_error(einval)?;
+                return Ok(-1);
+            }
+        };
+        // If adding the duration overflows, let's just sleep for an hour. Waking up early is always acceptable.
+        let now = this.machine.clock.now();
+        let timeout_time = now
+            .checked_add(duration)
+            .unwrap_or_else(|| now.checked_add(Duration::from_secs(3600)).unwrap());
+
+        let active_thread = this.get_active_thread();
+        this.block_thread(active_thread);
+
+        this.register_timeout_callback(
+            active_thread,
+            Time::Monotonic(timeout_time),
+            Box::new(move |ecx| {
+                ecx.unblock_thread(active_thread);
+                Ok(())
+            }),
+        );
+
+        Ok(0)
+    }
+
+    #[allow(non_snake_case)]
+    fn Sleep(&mut self, timeout: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("windows", "Sleep");
+
+        let timeout_ms = this.read_scalar(timeout)?.to_u32()?;
+
+        let duration = Duration::from_millis(timeout_ms.into());
+        let timeout_time = this.machine.clock.now().checked_add(duration).unwrap();
+
+        let active_thread = this.get_active_thread();
+        this.block_thread(active_thread);
+
+        this.register_timeout_callback(
+            active_thread,
+            Time::Monotonic(timeout_time),
+            Box::new(move |ecx| {
+                ecx.unblock_thread(active_thread);
+                Ok(())
+            }),
+        );
+
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/tls.rs b/src/tools/miri/src/shims/tls.rs
new file mode 100644
index 000000000000..d93d6a16a073
--- /dev/null
+++ b/src/tools/miri/src/shims/tls.rs
@@ -0,0 +1,400 @@
+//! Implement thread-local storage.
+
+use std::collections::btree_map::Entry as BTreeEntry;
+use std::collections::hash_map::Entry as HashMapEntry;
+use std::collections::BTreeMap;
+
+use log::trace;
+
+use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty;
+use rustc_target::abi::{HasDataLayout, Size};
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+
+pub type TlsKey = u128;
+
+#[derive(Clone, Debug)]
+pub struct TlsEntry<'tcx> {
+    /// The data for this key. None is used to represent NULL.
+    /// (We normalize this early to avoid having to do a NULL-ptr-test each time we access the data.)
+    data: BTreeMap<ThreadId, Scalar<Provenance>>,
+    dtor: Option<ty::Instance<'tcx>>,
+}
+
+#[derive(Clone, Debug)]
+struct RunningDtorsState {
+    /// The last TlsKey used to retrieve a TLS destructor. `None` means that we
+    /// have not tried to retrieve a TLS destructor yet or that we already tried
+    /// all keys.
+    last_dtor_key: Option<TlsKey>,
+}
+
+#[derive(Debug)]
+pub struct TlsData<'tcx> {
+    /// The Key to use for the next thread-local allocation.
+    next_key: TlsKey,
+
+    /// pthreads-style thread-local storage.
+    keys: BTreeMap<TlsKey, TlsEntry<'tcx>>,
+
+    /// A single per thread destructor of the thread local storage (that's how
+    /// things work on macOS) with a data argument.
+    macos_thread_dtors: BTreeMap<ThreadId, (ty::Instance<'tcx>, Scalar<Provenance>)>,
+
+    /// State for currently running TLS dtors. If this map contains a key for a
+    /// specific thread, it means that we are in the "destruct" phase, during
+    /// which some operations are UB.
+    dtors_running: FxHashMap<ThreadId, RunningDtorsState>,
+}
+
+impl<'tcx> Default for TlsData<'tcx> {
+    fn default() -> Self {
+        TlsData {
+            next_key: 1, // start with 1 as we must not use 0 on Windows
+            keys: Default::default(),
+            macos_thread_dtors: Default::default(),
+            dtors_running: Default::default(),
+        }
+    }
+}
+
+impl<'tcx> TlsData<'tcx> {
+    /// Generate a new TLS key with the given destructor.
+    /// `max_size` determines the integer size the key has to fit in.
+    #[allow(clippy::integer_arithmetic)]
+    pub fn create_tls_key(
+        &mut self,
+        dtor: Option<ty::Instance<'tcx>>,
+        max_size: Size,
+    ) -> InterpResult<'tcx, TlsKey> {
+        let new_key = self.next_key;
+        self.next_key += 1;
+        self.keys.try_insert(new_key, TlsEntry { data: Default::default(), dtor }).unwrap();
+        trace!("New TLS key allocated: {} with dtor {:?}", new_key, dtor);
+
+        if max_size.bits() < 128 && new_key >= (1u128 << max_size.bits()) {
+            throw_unsup_format!("we ran out of TLS key space");
+        }
+        Ok(new_key)
+    }
+
+    pub fn delete_tls_key(&mut self, key: TlsKey) -> InterpResult<'tcx> {
+        match self.keys.remove(&key) {
+            Some(_) => {
+                trace!("TLS key {} removed", key);
+                Ok(())
+            }
+            None => throw_ub_format!("removing a non-existig TLS key: {}", key),
+        }
+    }
+
+    pub fn load_tls(
+        &self,
+        key: TlsKey,
+        thread_id: ThreadId,
+        cx: &impl HasDataLayout,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        match self.keys.get(&key) {
+            Some(TlsEntry { data, .. }) => {
+                let value = data.get(&thread_id).copied();
+                trace!("TLS key {} for thread {:?} loaded: {:?}", key, thread_id, value);
+                Ok(value.unwrap_or_else(|| Scalar::null_ptr(cx)))
+            }
+            None => throw_ub_format!("loading from a non-existing TLS key: {}", key),
+        }
+    }
+
+    pub fn store_tls(
+        &mut self,
+        key: TlsKey,
+        thread_id: ThreadId,
+        new_data: Scalar<Provenance>,
+        cx: &impl HasDataLayout,
+    ) -> InterpResult<'tcx> {
+        match self.keys.get_mut(&key) {
+            Some(TlsEntry { data, .. }) => {
+                if new_data.to_machine_usize(cx)? != 0 {
+                    trace!("TLS key {} for thread {:?} stored: {:?}", key, thread_id, new_data);
+                    data.insert(thread_id, new_data);
+                } else {
+                    trace!("TLS key {} for thread {:?} removed", key, thread_id);
+                    data.remove(&thread_id);
+                }
+                Ok(())
+            }
+            None => throw_ub_format!("storing to a non-existing TLS key: {}", key),
+        }
+    }
+
+    /// Set the thread wide destructor of the thread local storage for the given
+    /// thread. This function is used to implement `_tlv_atexit` shim on MacOS.
+    ///
+    /// Thread wide dtors are available only on MacOS. There is one destructor
+    /// per thread as can be guessed from the following comment in the
+    /// [`_tlv_atexit`
+    /// implementation](https://github.com/opensource-apple/dyld/blob/195030646877261f0c8c7ad8b001f52d6a26f514/src/threadLocalVariables.c#L389):
+    ///
+    /// NOTE: this does not need locks because it only operates on current thread data
+    pub fn set_macos_thread_dtor(
+        &mut self,
+        thread: ThreadId,
+        dtor: ty::Instance<'tcx>,
+        data: Scalar<Provenance>,
+    ) -> InterpResult<'tcx> {
+        if self.dtors_running.contains_key(&thread) {
+            // UB, according to libstd docs.
+            throw_ub_format!(
+                "setting thread's local storage destructor while destructors are already running"
+            );
+        }
+        if self.macos_thread_dtors.insert(thread, (dtor, data)).is_some() {
+            throw_unsup_format!(
+                "setting more than one thread local storage destructor for the same thread is not supported"
+            );
+        }
+        Ok(())
+    }
+
+    /// Returns a dtor, its argument and its index, if one is supposed to run.
+    /// `key` is the last dtors that was run; we return the *next* one after that.
+    ///
+    /// An optional destructor function may be associated with each key value.
+    /// At thread exit, if a key value has a non-NULL destructor pointer,
+    /// and the thread has a non-NULL value associated with that key,
+    /// the value of the key is set to NULL, and then the function pointed
+    /// to is called with the previously associated value as its sole argument.
+    /// **The order of destructor calls is unspecified if more than one destructor
+    /// exists for a thread when it exits.**
+    ///
+    /// If, after all the destructors have been called for all non-NULL values
+    /// with associated destructors, there are still some non-NULL values with
+    /// associated destructors, then the process is repeated.
+    /// If, after at least {PTHREAD_DESTRUCTOR_ITERATIONS} iterations of destructor
+    /// calls for outstanding non-NULL values, there are still some non-NULL values
+    /// with associated destructors, implementations may stop calling destructors,
+    /// or they may continue calling destructors until no non-NULL values with
+    /// associated destructors exist, even though this might result in an infinite loop.
+    fn fetch_tls_dtor(
+        &mut self,
+        key: Option<TlsKey>,
+        thread_id: ThreadId,
+    ) -> Option<(ty::Instance<'tcx>, Scalar<Provenance>, TlsKey)> {
+        use std::ops::Bound::*;
+
+        let thread_local = &mut self.keys;
+        let start = match key {
+            Some(key) => Excluded(key),
+            None => Unbounded,
+        };
+        // We interpret the documentaion above (taken from POSIX) as saying that we need to iterate
+        // over all keys and run each destructor at least once before running any destructor a 2nd
+        // time. That's why we have `key` to indicate how far we got in the current iteration. If we
+        // return `None`, `schedule_next_pthread_tls_dtor` will re-try with `ket` set to `None` to
+        // start the next round.
+        // TODO: In the future, we might consider randomizing destructor order, but we still have to
+        // uphold this requirement.
+        for (&key, TlsEntry { data, dtor }) in thread_local.range_mut((start, Unbounded)) {
+            match data.entry(thread_id) {
+                BTreeEntry::Occupied(entry) => {
+                    if let Some(dtor) = dtor {
+                        // Set TLS data to NULL, and call dtor with old value.
+                        let data_scalar = entry.remove();
+                        let ret = Some((*dtor, data_scalar, key));
+                        return ret;
+                    }
+                }
+                BTreeEntry::Vacant(_) => {}
+            }
+        }
+        None
+    }
+
+    /// Set that dtors are running for `thread`. It is guaranteed not to change
+    /// the existing values stored in `dtors_running` for this thread. Returns
+    /// `true` if dtors for `thread` are already running.
+    fn set_dtors_running_for_thread(&mut self, thread: ThreadId) -> bool {
+        match self.dtors_running.entry(thread) {
+            HashMapEntry::Occupied(_) => true,
+            HashMapEntry::Vacant(entry) => {
+                // We cannot just do `self.dtors_running.insert` because that
+                // would overwrite `last_dtor_key` with `None`.
+                entry.insert(RunningDtorsState { last_dtor_key: None });
+                false
+            }
+        }
+    }
+
+    /// Delete all TLS entries for the given thread. This function should be
+    /// called after all TLS destructors have already finished.
+    fn delete_all_thread_tls(&mut self, thread_id: ThreadId) {
+        for TlsEntry { data, .. } in self.keys.values_mut() {
+            data.remove(&thread_id);
+        }
+    }
+
+    pub fn iter(&self, mut visitor: impl FnMut(&Scalar<Provenance>)) {
+        for scalar in self.keys.values().flat_map(|v| v.data.values()) {
+            visitor(scalar);
+        }
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextPrivExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+trait EvalContextPrivExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Schedule TLS destructors for Windows.
+    /// On windows, TLS destructors are managed by std.
+    fn schedule_windows_tls_dtors(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let active_thread = this.get_active_thread();
+
+        // Windows has a special magic linker section that is run on certain events.
+        // Instead of searching for that section and supporting arbitrary hooks in there
+        // (that would be basically https://github.com/rust-lang/miri/issues/450),
+        // we specifically look up the static in libstd that we know is placed
+        // in that section.
+        let thread_callback =
+            this.eval_windows("thread_local_key", "p_thread_callback")?.to_pointer(this)?;
+        let thread_callback = this.get_ptr_fn(thread_callback)?.as_instance()?;
+
+        // FIXME: Technically, the reason should be `DLL_PROCESS_DETACH` when the main thread exits
+        // but std treats both the same.
+        let reason = this.eval_windows("c", "DLL_THREAD_DETACH")?;
+
+        // The signature of this function is `unsafe extern "system" fn(h: c::LPVOID, dwReason: c::DWORD, pv: c::LPVOID)`.
+        // FIXME: `h` should be a handle to the current module and what `pv` should be is unknown
+        // but both are ignored by std
+        this.call_function(
+            thread_callback,
+            Abi::System { unwind: false },
+            &[Scalar::null_ptr(this).into(), reason.into(), Scalar::null_ptr(this).into()],
+            None,
+            StackPopCleanup::Root { cleanup: true },
+        )?;
+
+        this.enable_thread(active_thread);
+        Ok(())
+    }
+
+    /// Schedule the MacOS thread destructor of the thread local storage to be
+    /// executed. Returns `true` if scheduled.
+    ///
+    /// Note: It is safe to call this function also on other Unixes.
+    fn schedule_macos_tls_dtor(&mut self) -> InterpResult<'tcx, bool> {
+        let this = self.eval_context_mut();
+        let thread_id = this.get_active_thread();
+        if let Some((instance, data)) = this.machine.tls.macos_thread_dtors.remove(&thread_id) {
+            trace!("Running macos dtor {:?} on {:?} at {:?}", instance, data, thread_id);
+
+            this.call_function(
+                instance,
+                Abi::C { unwind: false },
+                &[data.into()],
+                None,
+                StackPopCleanup::Root { cleanup: true },
+            )?;
+
+            // Enable the thread so that it steps through the destructor which
+            // we just scheduled. Since we deleted the destructor, it is
+            // guaranteed that we will schedule it again. The `dtors_running`
+            // flag will prevent the code from adding the destructor again.
+            this.enable_thread(thread_id);
+            Ok(true)
+        } else {
+            Ok(false)
+        }
+    }
+
+    /// Schedule a pthread TLS destructor. Returns `true` if found
+    /// a destructor to schedule, and `false` otherwise.
+    fn schedule_next_pthread_tls_dtor(&mut self) -> InterpResult<'tcx, bool> {
+        let this = self.eval_context_mut();
+        let active_thread = this.get_active_thread();
+
+        assert!(this.has_terminated(active_thread), "running TLS dtors for non-terminated thread");
+        // Fetch next dtor after `key`.
+        let last_key = this.machine.tls.dtors_running[&active_thread].last_dtor_key;
+        let dtor = match this.machine.tls.fetch_tls_dtor(last_key, active_thread) {
+            dtor @ Some(_) => dtor,
+            // We ran each dtor once, start over from the beginning.
+            None => this.machine.tls.fetch_tls_dtor(None, active_thread),
+        };
+        if let Some((instance, ptr, key)) = dtor {
+            this.machine.tls.dtors_running.get_mut(&active_thread).unwrap().last_dtor_key =
+                Some(key);
+            trace!("Running TLS dtor {:?} on {:?} at {:?}", instance, ptr, active_thread);
+            assert!(
+                !ptr.to_machine_usize(this).unwrap() != 0,
+                "data can't be NULL when dtor is called!"
+            );
+
+            this.call_function(
+                instance,
+                Abi::C { unwind: false },
+                &[ptr.into()],
+                None,
+                StackPopCleanup::Root { cleanup: true },
+            )?;
+
+            this.enable_thread(active_thread);
+            return Ok(true);
+        }
+        this.machine.tls.dtors_running.get_mut(&active_thread).unwrap().last_dtor_key = None;
+
+        Ok(false)
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Schedule an active thread's TLS destructor to run on the active thread.
+    /// Note that this function does not run the destructors itself, it just
+    /// schedules them one by one each time it is called and reenables the
+    /// thread so that it can be executed normally by the main execution loop.
+    ///
+    /// Note: we consistently run TLS destructors for all threads, including the
+    /// main thread. However, it is not clear that we should run the TLS
+    /// destructors for the main thread. See issue:
+    /// <https://github.com/rust-lang/rust/issues/28129>.
+    fn schedule_next_tls_dtor_for_active_thread(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let active_thread = this.get_active_thread();
+        trace!("schedule_next_tls_dtor_for_active_thread on thread {:?}", active_thread);
+
+        if !this.machine.tls.set_dtors_running_for_thread(active_thread) {
+            // This is the first time we got asked to schedule a destructor. The
+            // Windows schedule destructor function must be called exactly once,
+            // this is why it is in this block.
+            if this.tcx.sess.target.os == "windows" {
+                // On Windows, we signal that the thread quit by starting the
+                // relevant function, reenabling the thread, and going back to
+                // the scheduler.
+                this.schedule_windows_tls_dtors()?;
+                return Ok(());
+            }
+        }
+        // The remaining dtors make some progress each time around the scheduler loop,
+        // until they return `false` to indicate that they are done.
+
+        // The macOS thread wide destructor runs "before any TLS slots get
+        // freed", so do that first.
+        if this.schedule_macos_tls_dtor()? {
+            // We have scheduled a MacOS dtor to run on the thread. Execute it
+            // to completion and come back here. Scheduling a destructor
+            // destroys it, so we will not enter this branch again.
+            return Ok(());
+        }
+        if this.schedule_next_pthread_tls_dtor()? {
+            // We have scheduled a pthread destructor and removed it from the
+            // destructors list. Run it to completion and come back here.
+            return Ok(());
+        }
+
+        // All dtors done!
+        this.machine.tls.delete_all_thread_tls(active_thread);
+        this.thread_terminated()?;
+
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/android/dlsym.rs b/src/tools/miri/src/shims/unix/android/dlsym.rs
new file mode 100644
index 000000000000..4cb78d4dabdc
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/android/dlsym.rs
@@ -0,0 +1,54 @@
+use rustc_middle::mir;
+
+use crate::helpers::check_arg_count;
+use crate::*;
+
+#[derive(Debug, Copy, Clone)]
+#[allow(non_camel_case_types)]
+pub enum Dlsym {
+    signal,
+}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        Ok(match name {
+            "signal" => Some(Dlsym::signal),
+            "android_set_abort_message" => None,
+            _ => throw_unsup_format!("unsupported Android dlsym: {}", name),
+        })
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let ret = ret.expect("we don't support any diverging dlsym");
+        assert!(this.tcx.sess.target.os == "android");
+
+        match dlsym {
+            Dlsym::signal => {
+                if !this.frame_in_std() {
+                    throw_unsup_format!(
+                        "`signal` support is crude and just enough for libstd to work"
+                    );
+                }
+
+                let &[ref _sig, ref _func] = check_arg_count(args)?;
+                this.write_null(dest)?;
+            }
+        }
+
+        log::trace!("{:?}", this.dump_place(**dest));
+        this.go_to_block(ret);
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/android/foreign_items.rs b/src/tools/miri/src/shims/unix/android/foreign_items.rs
new file mode 100644
index 000000000000..756aed369f15
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/android/foreign_items.rs
@@ -0,0 +1,26 @@
+use rustc_span::Symbol;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::foreign_items::EmulateByNameResult;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        _abi: Abi,
+        _args: &[OpTy<'tcx, Provenance>],
+        _dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let _this = self.eval_context_mut();
+        #[allow(clippy::match_single_binding)]
+        match link_name.as_str() {
+            _ => return Ok(EmulateByNameResult::NotSupported),
+        }
+
+        #[allow(unreachable_code)]
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/android/mod.rs b/src/tools/miri/src/shims/unix/android/mod.rs
new file mode 100644
index 000000000000..434f5f30b5a5
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/android/mod.rs
@@ -0,0 +1,2 @@
+pub mod dlsym;
+pub mod foreign_items;
diff --git a/src/tools/miri/src/shims/unix/dlsym.rs b/src/tools/miri/src/shims/unix/dlsym.rs
new file mode 100644
index 000000000000..8bc19d18f2b2
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/dlsym.rs
@@ -0,0 +1,55 @@
+use rustc_middle::mir;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::unix::android::dlsym as android;
+use shims::unix::freebsd::dlsym as freebsd;
+use shims::unix::linux::dlsym as linux;
+use shims::unix::macos::dlsym as macos;
+
+#[derive(Debug, Copy, Clone)]
+pub enum Dlsym {
+    Android(android::Dlsym),
+    FreeBsd(freebsd::Dlsym),
+    Linux(linux::Dlsym),
+    MacOs(macos::Dlsym),
+}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &str, target_os: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        Ok(match target_os {
+            "android" => android::Dlsym::from_str(name)?.map(Dlsym::Android),
+            "freebsd" => freebsd::Dlsym::from_str(name)?.map(Dlsym::FreeBsd),
+            "linux" => linux::Dlsym::from_str(name)?.map(Dlsym::Linux),
+            "macos" => macos::Dlsym::from_str(name)?.map(Dlsym::MacOs),
+            _ => panic!("unsupported Unix OS {target_os}"),
+        })
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        this.check_abi(abi, Abi::C { unwind: false })?;
+
+        match dlsym {
+            Dlsym::Android(dlsym) =>
+                android::EvalContextExt::call_dlsym(this, dlsym, args, dest, ret),
+            Dlsym::FreeBsd(dlsym) =>
+                freebsd::EvalContextExt::call_dlsym(this, dlsym, args, dest, ret),
+            Dlsym::Linux(dlsym) => linux::EvalContextExt::call_dlsym(this, dlsym, args, dest, ret),
+            Dlsym::MacOs(dlsym) => macos::EvalContextExt::call_dlsym(this, dlsym, args, dest, ret),
+        }
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/foreign_items.rs b/src/tools/miri/src/shims/unix/foreign_items.rs
new file mode 100644
index 000000000000..153e5852dcc8
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/foreign_items.rs
@@ -0,0 +1,606 @@
+use std::ffi::OsStr;
+
+use log::trace;
+
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_span::Symbol;
+use rustc_target::abi::{Align, Size};
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::foreign_items::EmulateByNameResult;
+use shims::unix::fs::EvalContextExt as _;
+use shims::unix::sync::EvalContextExt as _;
+use shims::unix::thread::EvalContextExt as _;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+
+        // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.
+        #[rustfmt::skip]
+        match link_name.as_str() {
+            // Environment related shims
+            "getenv" => {
+                let [name] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.getenv(name)?;
+                this.write_pointer(result, dest)?;
+            }
+            "unsetenv" => {
+                let [name] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.unsetenv(name)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "setenv" => {
+                let [name, value, overwrite] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_scalar(overwrite)?.to_i32()?;
+                let result = this.setenv(name, value)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "getcwd" => {
+                let [buf, size] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.getcwd(buf, size)?;
+                this.write_pointer(result, dest)?;
+            }
+            "chdir" => {
+                let [path] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.chdir(path)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // File related shims
+            "open" | "open64" => {
+                // `open` is variadic, the third argument is only present when the second argument has O_CREAT (or on linux O_TMPFILE, but miri doesn't support that) set
+                this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
+                let result = this.open(args)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "close" => {
+                let [fd] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.close(fd)?;
+                this.write_scalar(result, dest)?;
+            }
+            "fcntl" => {
+                // `fcntl` is variadic. The argument count is checked based on the first argument
+                // in `this.fcntl()`, so we do not use `check_shim` here.
+                this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
+                let result = this.fcntl(args)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "read" => {
+                let [fd, buf, count] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let fd = this.read_scalar(fd)?.to_i32()?;
+                let buf = this.read_pointer(buf)?;
+                let count = this.read_scalar(count)?.to_machine_usize(this)?;
+                let result = this.read(fd, buf, count)?;
+                this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
+            }
+            "write" => {
+                let [fd, buf, n] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let fd = this.read_scalar(fd)?.to_i32()?;
+                let buf = this.read_pointer(buf)?;
+                let count = this.read_scalar(n)?.to_machine_usize(this)?;
+                trace!("Called write({:?}, {:?}, {:?})", fd, buf, count);
+                let result = this.write(fd, buf, count)?;
+                // Now, `result` is the value we return back to the program.
+                this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
+            }
+            "unlink" => {
+                let [path] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.unlink(path)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "symlink" => {
+                let [target, linkpath] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.symlink(target, linkpath)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "rename" => {
+                let [oldpath, newpath] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.rename(oldpath, newpath)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "mkdir" => {
+                let [path, mode] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.mkdir(path, mode)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "rmdir" => {
+                let [path] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.rmdir(path)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "opendir" => {
+                let [name] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.opendir(name)?;
+                this.write_scalar(result, dest)?;
+            }
+            "closedir" => {
+                let [dirp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.closedir(dirp)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "lseek64" => {
+                let [fd, offset, whence] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.lseek64(fd, offset, whence)?;
+                this.write_scalar(result, dest)?;
+            }
+            "ftruncate64" => {
+                let [fd, length] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.ftruncate64(fd, length)?;
+                this.write_scalar(result, dest)?;
+            }
+            "fsync" => {
+                let [fd] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.fsync(fd)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "fdatasync" => {
+                let [fd] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.fdatasync(fd)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "readlink" => {
+                let [pathname, buf, bufsize] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.readlink(pathname, buf, bufsize)?;
+                this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
+            }
+            "posix_fadvise" => {
+                let [fd, offset, len, advice] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_scalar(fd)?.to_i32()?;
+                this.read_scalar(offset)?.to_machine_isize(this)?;
+                this.read_scalar(len)?.to_machine_isize(this)?;
+                this.read_scalar(advice)?.to_i32()?;
+                // fadvise is only informational, we can ignore it.
+                this.write_null(dest)?;
+            }
+            "realpath" => {
+                let [path, resolved_path] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.realpath(path, resolved_path)?;
+                this.write_scalar(result, dest)?;
+            }
+            "mkstemp" => {
+                let [template] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.mkstemp(template)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // Time related shims
+            "gettimeofday" => {
+                let [tv, tz] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.gettimeofday(tv, tz)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // Allocation
+            "posix_memalign" => {
+                let [ret, align, size] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ret = this.deref_operand(ret)?;
+                let align = this.read_scalar(align)?.to_machine_usize(this)?;
+                let size = this.read_scalar(size)?.to_machine_usize(this)?;
+                // Align must be power of 2, and also at least ptr-sized (POSIX rules).
+                // But failure to adhere to this is not UB, it's an error condition.
+                if !align.is_power_of_two() || align < this.pointer_size().bytes() {
+                    let einval = this.eval_libc_i32("EINVAL")?;
+                    this.write_int(einval, dest)?;
+                } else {
+                    if size == 0 {
+                        this.write_null(&ret.into())?;
+                    } else {
+                        let ptr = this.allocate_ptr(
+                            Size::from_bytes(size),
+                            Align::from_bytes(align).unwrap(),
+                            MiriMemoryKind::C.into(),
+                        )?;
+                        this.write_pointer(ptr, &ret.into())?;
+                    }
+                    this.write_null(dest)?;
+                }
+            }
+
+            // Dynamic symbol loading
+            "dlsym" => {
+                let [handle, symbol] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_scalar(handle)?.to_machine_usize(this)?;
+                let symbol = this.read_pointer(symbol)?;
+                let symbol_name = this.read_c_str(symbol)?;
+                if let Some(dlsym) = Dlsym::from_str(symbol_name, &this.tcx.sess.target.os)? {
+                    let ptr = this.create_fn_alloc_ptr(FnVal::Other(dlsym));
+                    this.write_pointer(ptr, dest)?;
+                } else {
+                    this.write_null(dest)?;
+                }
+            }
+
+            // Querying system information
+            "sysconf" => {
+                let [name] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let name = this.read_scalar(name)?.to_i32()?;
+
+                // FIXME: Which of these are POSIX, and which are GNU/Linux?
+                // At least the names seem to all also exist on macOS.
+                let sysconfs: &[(&str, fn(&MiriInterpCx<'_, '_>) -> Scalar<Provenance>)] = &[
+                    ("_SC_PAGESIZE", |this| Scalar::from_int(PAGE_SIZE, this.pointer_size())),
+                    ("_SC_NPROCESSORS_CONF", |this| Scalar::from_int(NUM_CPUS, this.pointer_size())),
+                    ("_SC_NPROCESSORS_ONLN", |this| Scalar::from_int(NUM_CPUS, this.pointer_size())),
+                    // 512 seems to be a reasonable default. The value is not critical, in
+                    // the sense that getpwuid_r takes and checks the buffer length.
+                    ("_SC_GETPW_R_SIZE_MAX", |this| Scalar::from_int(512, this.pointer_size()))
+                ];
+                let mut result = None;
+                for &(sysconf_name, value) in sysconfs {
+                    let sysconf_name = this.eval_libc_i32(sysconf_name)?;
+                    if sysconf_name == name {
+                        result = Some(value(this));
+                        break;
+                    }
+                }
+                if let Some(result) = result {
+                    this.write_scalar(result, dest)?;
+                } else {
+                    throw_unsup_format!("unimplemented sysconf name: {}", name)
+                }
+            }
+
+            // Thread-local storage
+            "pthread_key_create" => {
+                let [key, dtor] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let key_place = this.deref_operand(key)?;
+                let dtor = this.read_pointer(dtor)?;
+
+                // Extract the function type out of the signature (that seems easier than constructing it ourselves).
+                let dtor = if !this.ptr_is_null(dtor)? {
+                    Some(this.get_ptr_fn(dtor)?.as_instance()?)
+                } else {
+                    None
+                };
+
+                // Figure out how large a pthread TLS key actually is.
+                // To this end, deref the argument type. This is `libc::pthread_key_t`.
+                let key_type = key.layout.ty
+                    .builtin_deref(true)
+                    .ok_or_else(|| err_ub_format!(
+                        "wrong signature used for `pthread_key_create`: first argument must be a raw pointer."
+                    ))?
+                    .ty;
+                let key_layout = this.layout_of(key_type)?;
+
+                // Create key and write it into the memory where `key_ptr` wants it.
+                let key = this.machine.tls.create_tls_key(dtor, key_layout.size)?;
+                this.write_scalar(Scalar::from_uint(key, key_layout.size), &key_place.into())?;
+
+                // Return success (`0`).
+                this.write_null(dest)?;
+            }
+            "pthread_key_delete" => {
+                let [key] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let key = this.read_scalar(key)?.to_bits(key.layout.size)?;
+                this.machine.tls.delete_tls_key(key)?;
+                // Return success (0)
+                this.write_null(dest)?;
+            }
+            "pthread_getspecific" => {
+                let [key] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let key = this.read_scalar(key)?.to_bits(key.layout.size)?;
+                let active_thread = this.get_active_thread();
+                let ptr = this.machine.tls.load_tls(key, active_thread, this)?;
+                this.write_scalar(ptr, dest)?;
+            }
+            "pthread_setspecific" => {
+                let [key, new_ptr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let key = this.read_scalar(key)?.to_bits(key.layout.size)?;
+                let active_thread = this.get_active_thread();
+                let new_data = this.read_scalar(new_ptr)?;
+                this.machine.tls.store_tls(key, active_thread, new_data, &*this.tcx)?;
+
+                // Return success (`0`).
+                this.write_null(dest)?;
+            }
+
+            // Synchronization primitives
+            "pthread_mutexattr_init" => {
+                let [attr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutexattr_init(attr)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutexattr_settype" => {
+                let [attr, kind] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutexattr_settype(attr, kind)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutexattr_destroy" => {
+                let [attr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutexattr_destroy(attr)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutex_init" => {
+                let [mutex, attr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutex_init(mutex, attr)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutex_lock" => {
+                let [mutex] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutex_lock(mutex)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutex_trylock" => {
+                let [mutex] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutex_trylock(mutex)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutex_unlock" => {
+                let [mutex] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutex_unlock(mutex)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_mutex_destroy" => {
+                let [mutex] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_mutex_destroy(mutex)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_rwlock_rdlock" => {
+                let [rwlock] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_rwlock_rdlock(rwlock)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_rwlock_tryrdlock" => {
+                let [rwlock] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_rwlock_tryrdlock(rwlock)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_rwlock_wrlock" => {
+                let [rwlock] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_rwlock_wrlock(rwlock)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_rwlock_trywrlock" => {
+                let [rwlock] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_rwlock_trywrlock(rwlock)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_rwlock_unlock" => {
+                let [rwlock] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_rwlock_unlock(rwlock)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_rwlock_destroy" => {
+                let [rwlock] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_rwlock_destroy(rwlock)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_condattr_init" => {
+                let [attr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_condattr_init(attr)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_condattr_destroy" => {
+                let [attr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_condattr_destroy(attr)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_cond_init" => {
+                let [cond, attr] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_cond_init(cond, attr)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_cond_signal" => {
+                let [cond] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_cond_signal(cond)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_cond_broadcast" => {
+                let [cond] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_cond_broadcast(cond)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_cond_wait" => {
+                let [cond, mutex] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_cond_wait(cond, mutex)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_cond_timedwait" => {
+                let [cond, mutex, abstime] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.pthread_cond_timedwait(cond, mutex, abstime, dest)?;
+            }
+            "pthread_cond_destroy" => {
+                let [cond] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_cond_destroy(cond)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // Threading
+            "pthread_create" => {
+                let [thread, attr, start, arg] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_create(thread, attr, start, arg)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_join" => {
+                let [thread, retval] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_join(thread, retval)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_detach" => {
+                let [thread] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_detach(thread)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_self" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let res = this.pthread_self()?;
+                this.write_scalar(res, dest)?;
+            }
+            "sched_yield" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.sched_yield()?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "nanosleep" => {
+                let [req, rem] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.nanosleep(req, rem)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // Miscellaneous
+            "isatty" => {
+                let [fd] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.isatty(fd)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "pthread_atfork" => {
+                let [prepare, parent, child] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_pointer(prepare)?;
+                this.read_pointer(parent)?;
+                this.read_pointer(child)?;
+                // We do not support forking, so there is nothing to do here.
+                this.write_null(dest)?;
+            }
+            "strerror_r" | "__xpg_strerror_r" => {
+                let [errnum, buf, buflen] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let errnum = this.read_scalar(errnum)?;
+                let buf = this.read_pointer(buf)?;
+                let buflen = this.read_scalar(buflen)?.to_machine_usize(this)?;
+
+                let error = this.try_errnum_to_io_error(errnum)?;
+                let formatted = match error {
+                    Some(err) => format!("{err}"),
+                    None => format!("<unknown errnum in strerror_r: {errnum}>"),
+                };
+                let (complete, _) = this.write_os_str_to_c_str(OsStr::new(&formatted), buf, buflen)?;
+                let ret = if complete { 0 } else { this.eval_libc_i32("ERANGE")? };
+                this.write_int(ret, dest)?;
+            }
+            "getpid" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false}, link_name, args)?;
+                let result = this.getpid()?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
+            // These shims are enabled only when the caller is in the standard library.
+            "pthread_attr_getguardsize"
+            if this.frame_in_std() => {
+                let [_attr, guard_size] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let guard_size = this.deref_operand(guard_size)?;
+                let guard_size_layout = this.libc_ty_layout("size_t")?;
+                this.write_scalar(Scalar::from_uint(crate::PAGE_SIZE, guard_size_layout.size), &guard_size.into())?;
+
+                // Return success (`0`).
+                this.write_null(dest)?;
+            }
+
+            | "pthread_attr_init"
+            | "pthread_attr_destroy"
+            if this.frame_in_std() => {
+                let [_] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_null(dest)?;
+            }
+            | "pthread_attr_setstacksize"
+            if this.frame_in_std() => {
+                let [_, _] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_null(dest)?;
+            }
+
+            "pthread_attr_getstack"
+            if this.frame_in_std() => {
+                // We don't support "pthread_attr_setstack", so we just pretend all stacks have the same values here.
+                // Hence we can mostly ignore the input `attr_place`.
+                let [attr_place, addr_place, size_place] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let _attr_place = this.deref_operand(attr_place)?;
+                let addr_place = this.deref_operand(addr_place)?;
+                let size_place = this.deref_operand(size_place)?;
+
+                this.write_scalar(
+                    Scalar::from_uint(STACK_ADDR, this.pointer_size()),
+                    &addr_place.into(),
+                )?;
+                this.write_scalar(
+                    Scalar::from_uint(STACK_SIZE, this.pointer_size()),
+                    &size_place.into(),
+                )?;
+
+                // Return success (`0`).
+                this.write_null(dest)?;
+            }
+
+            | "signal"
+            | "sigaltstack"
+            if this.frame_in_std() => {
+                let [_, _] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_null(dest)?;
+            }
+            | "sigaction"
+            | "mprotect"
+            if this.frame_in_std() => {
+                let [_, _, _] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_null(dest)?;
+            }
+
+            "getuid"
+            if this.frame_in_std() => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // FOr now, just pretend we always have this fixed UID.
+                this.write_int(super::UID, dest)?;
+            }
+
+            "getpwuid_r" if this.frame_in_std() => {
+                let [uid, pwd, buf, buflen, result] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.check_no_isolation("`getpwuid_r`")?;
+
+                let uid = this.read_scalar(uid)?.to_u32()?;
+                let pwd = this.deref_operand(pwd)?;
+                let buf = this.read_pointer(buf)?;
+                let buflen = this.read_scalar(buflen)?.to_machine_usize(this)?;
+                let result = this.deref_operand(result)?;
+
+                // Must be for "us".
+                if uid != crate::shims::unix::UID {
+                    throw_unsup_format!("`getpwuid_r` on other users is not supported");
+                }
+
+                // Reset all fields to `uninit` to make sure nobody reads them.
+                // (This is a std-only shim so we are okay with such hacks.)
+                this.write_uninit(&pwd.into())?;
+
+                // We only set the home_dir field.
+                #[allow(deprecated)]
+                let home_dir = std::env::home_dir().unwrap();
+                let (written, _) = this.write_path_to_c_str(&home_dir, buf, buflen)?;
+                let pw_dir = this.mplace_field_named(&pwd, "pw_dir")?;
+                this.write_pointer(buf, &pw_dir.into())?;
+
+                if written {
+                    this.write_pointer(pwd.ptr, &result.into())?;
+                    this.write_null(dest)?;
+                } else {
+                    this.write_null(&result.into())?;
+                    this.write_scalar(this.eval_libc("ERANGE")?, dest)?;
+                }
+            }
+
+            // Platform-specific shims
+            _ => {
+                let target_os = &*this.tcx.sess.target.os;
+                match target_os {
+                    "android" => return shims::unix::android::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest),
+                    "freebsd" => return shims::unix::freebsd::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest),
+                    "linux" => return shims::unix::linux::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest),
+                    "macos" => return shims::unix::macos::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest),
+                    _ => panic!("unsupported Unix OS {target_os}"),
+                }
+            }
+        };
+
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/freebsd/dlsym.rs b/src/tools/miri/src/shims/unix/freebsd/dlsym.rs
new file mode 100644
index 000000000000..d759ffb8994b
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/freebsd/dlsym.rs
@@ -0,0 +1,36 @@
+use rustc_middle::mir;
+
+use crate::*;
+
+#[derive(Debug, Copy, Clone)]
+#[allow(non_camel_case_types)]
+pub enum Dlsym {}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        throw_unsup_format!("unsupported FreeBSD dlsym: {}", name)
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        _args: &[OpTy<'tcx, Provenance>],
+        _dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let _ret = ret.expect("we don't support any diverging dlsym");
+        assert!(this.tcx.sess.target.os == "freebsd");
+
+        match dlsym {}
+
+        //trace!("{:?}", this.dump_place(**dest));
+        //this.go_to_block(ret);
+        //Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/freebsd/foreign_items.rs b/src/tools/miri/src/shims/unix/freebsd/foreign_items.rs
new file mode 100644
index 000000000000..70798f981745
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/freebsd/foreign_items.rs
@@ -0,0 +1,45 @@
+use rustc_span::Symbol;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::foreign_items::EmulateByNameResult;
+use shims::unix::thread::EvalContextExt as _;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+        match link_name.as_str() {
+            // Threading
+            "pthread_attr_get_np" if this.frame_in_std() => {
+                let [_thread, _attr] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_null(dest)?;
+            }
+            "pthread_set_name_np" => {
+                let [thread, name] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let res =
+                    this.pthread_setname_np(this.read_scalar(thread)?, this.read_scalar(name)?)?;
+                this.write_scalar(res, dest)?;
+            }
+
+            // errno
+            "__error" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let errno_place = this.last_error_place()?;
+                this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
+            }
+
+            _ => return Ok(EmulateByNameResult::NotSupported),
+        }
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/freebsd/mod.rs b/src/tools/miri/src/shims/unix/freebsd/mod.rs
new file mode 100644
index 000000000000..434f5f30b5a5
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/freebsd/mod.rs
@@ -0,0 +1,2 @@
+pub mod dlsym;
+pub mod foreign_items;
diff --git a/src/tools/miri/src/shims/unix/fs.rs b/src/tools/miri/src/shims/unix/fs.rs
new file mode 100644
index 000000000000..8464c4589ed5
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/fs.rs
@@ -0,0 +1,1952 @@
+use std::borrow::Cow;
+use std::collections::BTreeMap;
+use std::convert::TryInto;
+use std::fs::{
+    read_dir, remove_dir, remove_file, rename, DirBuilder, File, FileType, OpenOptions, ReadDir,
+};
+use std::io::{self, ErrorKind, Read, Seek, SeekFrom, Write};
+use std::path::{Path, PathBuf};
+use std::time::SystemTime;
+
+use log::trace;
+
+use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty::{self, layout::LayoutOf};
+use rustc_target::abi::{Align, Size};
+
+use crate::shims::os_str::bytes_to_os_str;
+use crate::*;
+use shims::os_str::os_str_to_bytes;
+use shims::time::system_time_to_duration;
+
+#[derive(Debug)]
+struct FileHandle {
+    file: File,
+    writable: bool,
+}
+
+trait FileDescriptor: std::fmt::Debug {
+    fn name(&self) -> &'static str;
+
+    fn as_file_handle<'tcx>(&self) -> InterpResult<'tcx, &FileHandle> {
+        throw_unsup_format!("{} cannot be used as FileHandle", self.name());
+    }
+
+    fn read<'tcx>(
+        &mut self,
+        _communicate_allowed: bool,
+        _bytes: &mut [u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        throw_unsup_format!("cannot read from {}", self.name());
+    }
+
+    fn write<'tcx>(
+        &self,
+        _communicate_allowed: bool,
+        _bytes: &[u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        throw_unsup_format!("cannot write to {}", self.name());
+    }
+
+    fn seek<'tcx>(
+        &mut self,
+        _communicate_allowed: bool,
+        _offset: SeekFrom,
+    ) -> InterpResult<'tcx, io::Result<u64>> {
+        throw_unsup_format!("cannot seek on {}", self.name());
+    }
+
+    fn close<'tcx>(
+        self: Box<Self>,
+        _communicate_allowed: bool,
+    ) -> InterpResult<'tcx, io::Result<i32>> {
+        throw_unsup_format!("cannot close {}", self.name());
+    }
+
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>>;
+
+    #[cfg(unix)]
+    fn as_unix_host_fd(&self) -> Option<i32> {
+        None
+    }
+}
+
+impl FileDescriptor for FileHandle {
+    fn name(&self) -> &'static str {
+        "FILE"
+    }
+
+    fn as_file_handle<'tcx>(&self) -> InterpResult<'tcx, &FileHandle> {
+        Ok(self)
+    }
+
+    fn read<'tcx>(
+        &mut self,
+        communicate_allowed: bool,
+        bytes: &mut [u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        assert!(communicate_allowed, "isolation should have prevented even opening a file");
+        Ok(self.file.read(bytes))
+    }
+
+    fn write<'tcx>(
+        &self,
+        communicate_allowed: bool,
+        bytes: &[u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        assert!(communicate_allowed, "isolation should have prevented even opening a file");
+        Ok((&mut &self.file).write(bytes))
+    }
+
+    fn seek<'tcx>(
+        &mut self,
+        communicate_allowed: bool,
+        offset: SeekFrom,
+    ) -> InterpResult<'tcx, io::Result<u64>> {
+        assert!(communicate_allowed, "isolation should have prevented even opening a file");
+        Ok(self.file.seek(offset))
+    }
+
+    fn close<'tcx>(
+        self: Box<Self>,
+        communicate_allowed: bool,
+    ) -> InterpResult<'tcx, io::Result<i32>> {
+        assert!(communicate_allowed, "isolation should have prevented even opening a file");
+        // We sync the file if it was opened in a mode different than read-only.
+        if self.writable {
+            // `File::sync_all` does the checks that are done when closing a file. We do this to
+            // to handle possible errors correctly.
+            let result = self.file.sync_all().map(|_| 0i32);
+            // Now we actually close the file.
+            drop(self);
+            // And return the result.
+            Ok(result)
+        } else {
+            // We drop the file, this closes it but ignores any errors
+            // produced when closing it. This is done because
+            // `File::sync_all` cannot be done over files like
+            // `/dev/urandom` which are read-only. Check
+            // https://github.com/rust-lang/miri/issues/999#issuecomment-568920439
+            // for a deeper discussion.
+            drop(self);
+            Ok(Ok(0))
+        }
+    }
+
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+        let duplicated = self.file.try_clone()?;
+        Ok(Box::new(FileHandle { file: duplicated, writable: self.writable }))
+    }
+
+    #[cfg(unix)]
+    fn as_unix_host_fd(&self) -> Option<i32> {
+        use std::os::unix::io::AsRawFd;
+        Some(self.file.as_raw_fd())
+    }
+}
+
+impl FileDescriptor for io::Stdin {
+    fn name(&self) -> &'static str {
+        "stdin"
+    }
+
+    fn read<'tcx>(
+        &mut self,
+        communicate_allowed: bool,
+        bytes: &mut [u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        if !communicate_allowed {
+            // We want isolation mode to be deterministic, so we have to disallow all reads, even stdin.
+            helpers::isolation_abort_error("`read` from stdin")?;
+        }
+        Ok(Read::read(self, bytes))
+    }
+
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+        Ok(Box::new(io::stdin()))
+    }
+
+    #[cfg(unix)]
+    fn as_unix_host_fd(&self) -> Option<i32> {
+        Some(libc::STDIN_FILENO)
+    }
+}
+
+impl FileDescriptor for io::Stdout {
+    fn name(&self) -> &'static str {
+        "stdout"
+    }
+
+    fn write<'tcx>(
+        &self,
+        _communicate_allowed: bool,
+        bytes: &[u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        // We allow writing to stderr even with isolation enabled.
+        let result = Write::write(&mut { self }, bytes);
+        // Stdout is buffered, flush to make sure it appears on the
+        // screen.  This is the write() syscall of the interpreted
+        // program, we want it to correspond to a write() syscall on
+        // the host -- there is no good in adding extra buffering
+        // here.
+        io::stdout().flush().unwrap();
+
+        Ok(result)
+    }
+
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+        Ok(Box::new(io::stdout()))
+    }
+
+    #[cfg(unix)]
+    fn as_unix_host_fd(&self) -> Option<i32> {
+        Some(libc::STDOUT_FILENO)
+    }
+}
+
+impl FileDescriptor for io::Stderr {
+    fn name(&self) -> &'static str {
+        "stderr"
+    }
+
+    fn write<'tcx>(
+        &self,
+        _communicate_allowed: bool,
+        bytes: &[u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        // We allow writing to stderr even with isolation enabled.
+        // No need to flush, stderr is not buffered.
+        Ok(Write::write(&mut { self }, bytes))
+    }
+
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+        Ok(Box::new(io::stderr()))
+    }
+
+    #[cfg(unix)]
+    fn as_unix_host_fd(&self) -> Option<i32> {
+        Some(libc::STDERR_FILENO)
+    }
+}
+
+#[derive(Debug)]
+struct DummyOutput;
+
+impl FileDescriptor for DummyOutput {
+    fn name(&self) -> &'static str {
+        "stderr and stdout"
+    }
+
+    fn write<'tcx>(
+        &self,
+        _communicate_allowed: bool,
+        bytes: &[u8],
+    ) -> InterpResult<'tcx, io::Result<usize>> {
+        // We just don't write anything, but report to the user that we did.
+        Ok(Ok(bytes.len()))
+    }
+
+    fn dup(&mut self) -> io::Result<Box<dyn FileDescriptor>> {
+        Ok(Box::new(DummyOutput))
+    }
+}
+
+#[derive(Debug)]
+pub struct FileHandler {
+    handles: BTreeMap<i32, Box<dyn FileDescriptor>>,
+}
+
+impl FileHandler {
+    pub(crate) fn new(mute_stdout_stderr: bool) -> FileHandler {
+        let mut handles: BTreeMap<_, Box<dyn FileDescriptor>> = BTreeMap::new();
+        handles.insert(0i32, Box::new(io::stdin()));
+        if mute_stdout_stderr {
+            handles.insert(1i32, Box::new(DummyOutput));
+            handles.insert(2i32, Box::new(DummyOutput));
+        } else {
+            handles.insert(1i32, Box::new(io::stdout()));
+            handles.insert(2i32, Box::new(io::stderr()));
+        }
+        FileHandler { handles }
+    }
+
+    fn insert_fd(&mut self, file_handle: Box<dyn FileDescriptor>) -> i32 {
+        self.insert_fd_with_min_fd(file_handle, 0)
+    }
+
+    fn insert_fd_with_min_fd(&mut self, file_handle: Box<dyn FileDescriptor>, min_fd: i32) -> i32 {
+        // Find the lowest unused FD, starting from min_fd. If the first such unused FD is in
+        // between used FDs, the find_map combinator will return it. If the first such unused FD
+        // is after all other used FDs, the find_map combinator will return None, and we will use
+        // the FD following the greatest FD thus far.
+        let candidate_new_fd =
+            self.handles.range(min_fd..).zip(min_fd..).find_map(|((fd, _fh), counter)| {
+                if *fd != counter {
+                    // There was a gap in the fds stored, return the first unused one
+                    // (note that this relies on BTreeMap iterating in key order)
+                    Some(counter)
+                } else {
+                    // This fd is used, keep going
+                    None
+                }
+            });
+        let new_fd = candidate_new_fd.unwrap_or_else(|| {
+            // find_map ran out of BTreeMap entries before finding a free fd, use one plus the
+            // maximum fd in the map
+            self.handles
+                .last_key_value()
+                .map(|(fd, _)| fd.checked_add(1).unwrap())
+                .unwrap_or(min_fd)
+        });
+
+        self.handles.try_insert(new_fd, file_handle).unwrap();
+        new_fd
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExtPrivate<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+trait EvalContextExtPrivate<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn macos_stat_write_buf(
+        &mut self,
+        metadata: FileMetadata,
+        buf_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let mode: u16 = metadata.mode.to_u16()?;
+
+        let (access_sec, access_nsec) = metadata.accessed.unwrap_or((0, 0));
+        let (created_sec, created_nsec) = metadata.created.unwrap_or((0, 0));
+        let (modified_sec, modified_nsec) = metadata.modified.unwrap_or((0, 0));
+
+        let buf = this.deref_operand(buf_op)?;
+        this.write_int_fields_named(
+            &[
+                ("st_dev", 0),
+                ("st_mode", mode.into()),
+                ("st_nlink", 0),
+                ("st_ino", 0),
+                ("st_uid", 0),
+                ("st_gid", 0),
+                ("st_rdev", 0),
+                ("st_atime", access_sec.into()),
+                ("st_atime_nsec", access_nsec.into()),
+                ("st_mtime", modified_sec.into()),
+                ("st_mtime_nsec", modified_nsec.into()),
+                ("st_ctime", 0),
+                ("st_ctime_nsec", 0),
+                ("st_birthtime", created_sec.into()),
+                ("st_birthtime_nsec", created_nsec.into()),
+                ("st_size", metadata.size.into()),
+                ("st_blocks", 0),
+                ("st_blksize", 0),
+                ("st_flags", 0),
+                ("st_gen", 0),
+            ],
+            &buf,
+        )?;
+
+        Ok(0)
+    }
+
+    /// Function used when a handle is not found inside `FileHandler`. It returns `Ok(-1)`and sets
+    /// the last OS error to `libc::EBADF` (invalid file descriptor). This function uses
+    /// `T: From<i32>` instead of `i32` directly because some fs functions return different integer
+    /// types (like `read`, that returns an `i64`).
+    fn handle_not_found<T: From<i32>>(&mut self) -> InterpResult<'tcx, T> {
+        let this = self.eval_context_mut();
+        let ebadf = this.eval_libc("EBADF")?;
+        this.set_last_error(ebadf)?;
+        Ok((-1).into())
+    }
+
+    fn file_type_to_d_type(
+        &mut self,
+        file_type: std::io::Result<FileType>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        match file_type {
+            Ok(file_type) => {
+                if file_type.is_dir() {
+                    Ok(this.eval_libc("DT_DIR")?.to_u8()?.into())
+                } else if file_type.is_file() {
+                    Ok(this.eval_libc("DT_REG")?.to_u8()?.into())
+                } else if file_type.is_symlink() {
+                    Ok(this.eval_libc("DT_LNK")?.to_u8()?.into())
+                } else {
+                    // Certain file types are only supported when the host is a Unix system.
+                    // (i.e. devices and sockets) If it is, check those cases, if not, fall back to
+                    // DT_UNKNOWN sooner.
+
+                    #[cfg(unix)]
+                    {
+                        use std::os::unix::fs::FileTypeExt;
+                        if file_type.is_block_device() {
+                            Ok(this.eval_libc("DT_BLK")?.to_u8()?.into())
+                        } else if file_type.is_char_device() {
+                            Ok(this.eval_libc("DT_CHR")?.to_u8()?.into())
+                        } else if file_type.is_fifo() {
+                            Ok(this.eval_libc("DT_FIFO")?.to_u8()?.into())
+                        } else if file_type.is_socket() {
+                            Ok(this.eval_libc("DT_SOCK")?.to_u8()?.into())
+                        } else {
+                            Ok(this.eval_libc("DT_UNKNOWN")?.to_u8()?.into())
+                        }
+                    }
+                    #[cfg(not(unix))]
+                    Ok(this.eval_libc("DT_UNKNOWN")?.to_u8()?.into())
+                }
+            }
+            Err(e) =>
+                match e.raw_os_error() {
+                    Some(error) => Ok(error),
+                    None =>
+                        throw_unsup_format!(
+                            "the error {} couldn't be converted to a return value",
+                            e
+                        ),
+                },
+        }
+    }
+}
+
+/// An open directory, tracked by DirHandler.
+#[derive(Debug)]
+pub struct OpenDir {
+    /// The directory reader on the host.
+    read_dir: ReadDir,
+    /// The most recent entry returned by readdir()
+    entry: Pointer<Option<Provenance>>,
+}
+
+impl OpenDir {
+    fn new(read_dir: ReadDir) -> Self {
+        // We rely on `free` being a NOP on null pointers.
+        Self { read_dir, entry: Pointer::null() }
+    }
+}
+
+#[derive(Debug)]
+pub struct DirHandler {
+    /// Directory iterators used to emulate libc "directory streams", as used in opendir, readdir,
+    /// and closedir.
+    ///
+    /// When opendir is called, a directory iterator is created on the host for the target
+    /// directory, and an entry is stored in this hash map, indexed by an ID which represents
+    /// the directory stream. When readdir is called, the directory stream ID is used to look up
+    /// the corresponding ReadDir iterator from this map, and information from the next
+    /// directory entry is returned. When closedir is called, the ReadDir iterator is removed from
+    /// the map.
+    streams: FxHashMap<u64, OpenDir>,
+    /// ID number to be used by the next call to opendir
+    next_id: u64,
+}
+
+impl DirHandler {
+    #[allow(clippy::integer_arithmetic)]
+    fn insert_new(&mut self, read_dir: ReadDir) -> u64 {
+        let id = self.next_id;
+        self.next_id += 1;
+        self.streams.try_insert(id, OpenDir::new(read_dir)).unwrap();
+        id
+    }
+}
+
+impl Default for DirHandler {
+    fn default() -> DirHandler {
+        DirHandler {
+            streams: FxHashMap::default(),
+            // Skip 0 as an ID, because it looks like a null pointer to libc
+            next_id: 1,
+        }
+    }
+}
+
+fn maybe_sync_file(
+    file: &File,
+    writable: bool,
+    operation: fn(&File) -> std::io::Result<()>,
+) -> std::io::Result<i32> {
+    if !writable && cfg!(windows) {
+        // sync_all() and sync_data() will return an error on Windows hosts if the file is not opened
+        // for writing. (FlushFileBuffers requires that the file handle have the
+        // GENERIC_WRITE right)
+        Ok(0i32)
+    } else {
+        let result = operation(file);
+        result.map(|_| 0i32)
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn open(&mut self, args: &[OpTy<'tcx, Provenance>]) -> InterpResult<'tcx, i32> {
+        if args.len() < 2 {
+            throw_ub_format!(
+                "incorrect number of arguments for `open`: got {}, expected at least 2",
+                args.len()
+            );
+        }
+
+        let this = self.eval_context_mut();
+
+        let path = this.read_pointer(&args[0])?;
+        let flag = this.read_scalar(&args[1])?.to_i32()?;
+
+        let mut options = OpenOptions::new();
+
+        let o_rdonly = this.eval_libc_i32("O_RDONLY")?;
+        let o_wronly = this.eval_libc_i32("O_WRONLY")?;
+        let o_rdwr = this.eval_libc_i32("O_RDWR")?;
+        // The first two bits of the flag correspond to the access mode in linux, macOS and
+        // windows. We need to check that in fact the access mode flags for the current target
+        // only use these two bits, otherwise we are in an unsupported target and should error.
+        if (o_rdonly | o_wronly | o_rdwr) & !0b11 != 0 {
+            throw_unsup_format!("access mode flags on this target are unsupported");
+        }
+        let mut writable = true;
+
+        // Now we check the access mode
+        let access_mode = flag & 0b11;
+
+        if access_mode == o_rdonly {
+            writable = false;
+            options.read(true);
+        } else if access_mode == o_wronly {
+            options.write(true);
+        } else if access_mode == o_rdwr {
+            options.read(true).write(true);
+        } else {
+            throw_unsup_format!("unsupported access mode {:#x}", access_mode);
+        }
+        // We need to check that there aren't unsupported options in `flag`. For this we try to
+        // reproduce the content of `flag` in the `mirror` variable using only the supported
+        // options.
+        let mut mirror = access_mode;
+
+        let o_append = this.eval_libc_i32("O_APPEND")?;
+        if flag & o_append != 0 {
+            options.append(true);
+            mirror |= o_append;
+        }
+        let o_trunc = this.eval_libc_i32("O_TRUNC")?;
+        if flag & o_trunc != 0 {
+            options.truncate(true);
+            mirror |= o_trunc;
+        }
+        let o_creat = this.eval_libc_i32("O_CREAT")?;
+        if flag & o_creat != 0 {
+            // Get the mode.  On macOS, the argument type `mode_t` is actually `u16`, but
+            // C integer promotion rules mean that on the ABI level, it gets passed as `u32`
+            // (see https://github.com/rust-lang/rust/issues/71915).
+            let mode = if let Some(arg) = args.get(2) {
+                this.read_scalar(arg)?.to_u32()?
+            } else {
+                throw_ub_format!(
+                    "incorrect number of arguments for `open` with `O_CREAT`: got {}, expected at least 3",
+                    args.len()
+                );
+            };
+
+            if mode != 0o666 {
+                throw_unsup_format!("non-default mode 0o{:o} is not supported", mode);
+            }
+
+            mirror |= o_creat;
+
+            let o_excl = this.eval_libc_i32("O_EXCL")?;
+            if flag & o_excl != 0 {
+                mirror |= o_excl;
+                options.create_new(true);
+            } else {
+                options.create(true);
+            }
+        }
+        let o_cloexec = this.eval_libc_i32("O_CLOEXEC")?;
+        if flag & o_cloexec != 0 {
+            // We do not need to do anything for this flag because `std` already sets it.
+            // (Technically we do not support *not* setting this flag, but we ignore that.)
+            mirror |= o_cloexec;
+        }
+        // If `flag` is not equal to `mirror`, there is an unsupported option enabled in `flag`,
+        // then we throw an error.
+        if flag != mirror {
+            throw_unsup_format!("unsupported flags {:#x}", flag & !mirror);
+        }
+
+        let path = this.read_path_from_c_str(path)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`open`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        let fd = options.open(&path).map(|file| {
+            let fh = &mut this.machine.file_handler;
+            fh.insert_fd(Box::new(FileHandle { file, writable }))
+        });
+
+        this.try_unwrap_io_result(fd)
+    }
+
+    fn fcntl(&mut self, args: &[OpTy<'tcx, Provenance>]) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        if args.len() < 2 {
+            throw_ub_format!(
+                "incorrect number of arguments for fcntl: got {}, expected at least 2",
+                args.len()
+            );
+        }
+        let fd = this.read_scalar(&args[0])?.to_i32()?;
+        let cmd = this.read_scalar(&args[1])?.to_i32()?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`fcntl`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        // We only support getting the flags for a descriptor.
+        if cmd == this.eval_libc_i32("F_GETFD")? {
+            // Currently this is the only flag that `F_GETFD` returns. It is OK to just return the
+            // `FD_CLOEXEC` value without checking if the flag is set for the file because `std`
+            // always sets this flag when opening a file. However we still need to check that the
+            // file itself is open.
+            if this.machine.file_handler.handles.contains_key(&fd) {
+                Ok(this.eval_libc_i32("FD_CLOEXEC")?)
+            } else {
+                this.handle_not_found()
+            }
+        } else if cmd == this.eval_libc_i32("F_DUPFD")?
+            || cmd == this.eval_libc_i32("F_DUPFD_CLOEXEC")?
+        {
+            // Note that we always assume the FD_CLOEXEC flag is set for every open file, in part
+            // because exec() isn't supported. The F_DUPFD and F_DUPFD_CLOEXEC commands only
+            // differ in whether the FD_CLOEXEC flag is pre-set on the new file descriptor,
+            // thus they can share the same implementation here.
+            if args.len() < 3 {
+                throw_ub_format!(
+                    "incorrect number of arguments for fcntl with cmd=`F_DUPFD`/`F_DUPFD_CLOEXEC`: got {}, expected at least 3",
+                    args.len()
+                );
+            }
+            let start = this.read_scalar(&args[2])?.to_i32()?;
+
+            let fh = &mut this.machine.file_handler;
+
+            match fh.handles.get_mut(&fd) {
+                Some(file_descriptor) => {
+                    let dup_result = file_descriptor.dup();
+                    match dup_result {
+                        Ok(dup_fd) => Ok(fh.insert_fd_with_min_fd(dup_fd, start)),
+                        Err(e) => {
+                            this.set_last_error_from_io_error(e.kind())?;
+                            Ok(-1)
+                        }
+                    }
+                }
+                None => this.handle_not_found(),
+            }
+        } else if this.tcx.sess.target.os == "macos" && cmd == this.eval_libc_i32("F_FULLFSYNC")? {
+            if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
+                // FIXME: Support fullfsync for all FDs
+                let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
+                let io_result = maybe_sync_file(file, *writable, File::sync_all);
+                this.try_unwrap_io_result(io_result)
+            } else {
+                this.handle_not_found()
+            }
+        } else {
+            throw_unsup_format!("the {:#x} command is not supported for `fcntl`)", cmd);
+        }
+    }
+
+    fn close(&mut self, fd_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+
+        Ok(Scalar::from_i32(
+            if let Some(file_descriptor) = this.machine.file_handler.handles.remove(&fd) {
+                let result = file_descriptor.close(this.machine.communicate())?;
+                this.try_unwrap_io_result(result)?
+            } else {
+                this.handle_not_found()?
+            },
+        ))
+    }
+
+    fn read(
+        &mut self,
+        fd: i32,
+        buf: Pointer<Option<Provenance>>,
+        count: u64,
+    ) -> InterpResult<'tcx, i64> {
+        let this = self.eval_context_mut();
+
+        // Isolation check is done via `FileDescriptor` trait.
+
+        trace!("Reading from FD {}, size {}", fd, count);
+
+        // Check that the *entire* buffer is actually valid memory.
+        this.check_ptr_access_align(
+            buf,
+            Size::from_bytes(count),
+            Align::ONE,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
+
+        // We cap the number of read bytes to the largest value that we are able to fit in both the
+        // host's and target's `isize`. This saves us from having to handle overflows later.
+        let count = count
+            .min(u64::try_from(this.machine_isize_max()).unwrap())
+            .min(u64::try_from(isize::MAX).unwrap());
+        let communicate = this.machine.communicate();
+
+        if let Some(file_descriptor) = this.machine.file_handler.handles.get_mut(&fd) {
+            trace!("read: FD mapped to {:?}", file_descriptor);
+            // We want to read at most `count` bytes. We are sure that `count` is not negative
+            // because it was a target's `usize`. Also we are sure that its smaller than
+            // `usize::MAX` because it is bounded by the host's `isize`.
+            let mut bytes = vec![0; usize::try_from(count).unwrap()];
+            // `File::read` never returns a value larger than `count`,
+            // so this cannot fail.
+            let result =
+                file_descriptor.read(communicate, &mut bytes)?.map(|c| i64::try_from(c).unwrap());
+
+            match result {
+                Ok(read_bytes) => {
+                    // If reading to `bytes` did not fail, we write those bytes to the buffer.
+                    this.write_bytes_ptr(buf, bytes)?;
+                    Ok(read_bytes)
+                }
+                Err(e) => {
+                    this.set_last_error_from_io_error(e.kind())?;
+                    Ok(-1)
+                }
+            }
+        } else {
+            trace!("read: FD not found");
+            this.handle_not_found()
+        }
+    }
+
+    fn write(
+        &mut self,
+        fd: i32,
+        buf: Pointer<Option<Provenance>>,
+        count: u64,
+    ) -> InterpResult<'tcx, i64> {
+        let this = self.eval_context_mut();
+
+        // Isolation check is done via `FileDescriptor` trait.
+
+        // Check that the *entire* buffer is actually valid memory.
+        this.check_ptr_access_align(
+            buf,
+            Size::from_bytes(count),
+            Align::ONE,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
+
+        // We cap the number of written bytes to the largest value that we are able to fit in both the
+        // host's and target's `isize`. This saves us from having to handle overflows later.
+        let count = count
+            .min(u64::try_from(this.machine_isize_max()).unwrap())
+            .min(u64::try_from(isize::MAX).unwrap());
+        let communicate = this.machine.communicate();
+
+        if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
+            let bytes = this.read_bytes_ptr_strip_provenance(buf, Size::from_bytes(count))?;
+            let result =
+                file_descriptor.write(communicate, bytes)?.map(|c| i64::try_from(c).unwrap());
+            this.try_unwrap_io_result(result)
+        } else {
+            this.handle_not_found()
+        }
+    }
+
+    fn lseek64(
+        &mut self,
+        fd_op: &OpTy<'tcx, Provenance>,
+        offset_op: &OpTy<'tcx, Provenance>,
+        whence_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        // Isolation check is done via `FileDescriptor` trait.
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+        let offset = this.read_scalar(offset_op)?.to_i64()?;
+        let whence = this.read_scalar(whence_op)?.to_i32()?;
+
+        let seek_from = if whence == this.eval_libc_i32("SEEK_SET")? {
+            SeekFrom::Start(u64::try_from(offset).unwrap())
+        } else if whence == this.eval_libc_i32("SEEK_CUR")? {
+            SeekFrom::Current(offset)
+        } else if whence == this.eval_libc_i32("SEEK_END")? {
+            SeekFrom::End(offset)
+        } else {
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            return Ok(Scalar::from_i64(-1));
+        };
+
+        let communicate = this.machine.communicate();
+        Ok(Scalar::from_i64(
+            if let Some(file_descriptor) = this.machine.file_handler.handles.get_mut(&fd) {
+                let result = file_descriptor
+                    .seek(communicate, seek_from)?
+                    .map(|offset| i64::try_from(offset).unwrap());
+                this.try_unwrap_io_result(result)?
+            } else {
+                this.handle_not_found()?
+            },
+        ))
+    }
+
+    fn unlink(&mut self, path_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`unlink`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        let result = remove_file(path).map(|_| 0);
+        this.try_unwrap_io_result(result)
+    }
+
+    fn symlink(
+        &mut self,
+        target_op: &OpTy<'tcx, Provenance>,
+        linkpath_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        #[cfg(unix)]
+        fn create_link(src: &Path, dst: &Path) -> std::io::Result<()> {
+            std::os::unix::fs::symlink(src, dst)
+        }
+
+        #[cfg(windows)]
+        fn create_link(src: &Path, dst: &Path) -> std::io::Result<()> {
+            use std::os::windows::fs;
+            if src.is_dir() { fs::symlink_dir(src, dst) } else { fs::symlink_file(src, dst) }
+        }
+
+        let this = self.eval_context_mut();
+        let target = this.read_path_from_c_str(this.read_pointer(target_op)?)?;
+        let linkpath = this.read_path_from_c_str(this.read_pointer(linkpath_op)?)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`symlink`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        let result = create_link(&target, &linkpath).map(|_| 0);
+        this.try_unwrap_io_result(result)
+    }
+
+    fn macos_stat(
+        &mut self,
+        path_op: &OpTy<'tcx, Provenance>,
+        buf_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("macos", "stat");
+
+        let path_scalar = this.read_pointer(path_op)?;
+        let path = this.read_path_from_c_str(path_scalar)?.into_owned();
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`stat`", reject_with)?;
+            let eacc = this.eval_libc("EACCES")?;
+            this.set_last_error(eacc)?;
+            return Ok(Scalar::from_i32(-1));
+        }
+
+        // `stat` always follows symlinks.
+        let metadata = match FileMetadata::from_path(this, &path, true)? {
+            Some(metadata) => metadata,
+            None => return Ok(Scalar::from_i32(-1)), // `FileMetadata` has set errno
+        };
+
+        Ok(Scalar::from_i32(this.macos_stat_write_buf(metadata, buf_op)?))
+    }
+
+    // `lstat` is used to get symlink metadata.
+    fn macos_lstat(
+        &mut self,
+        path_op: &OpTy<'tcx, Provenance>,
+        buf_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os("macos", "lstat");
+
+        let path_scalar = this.read_pointer(path_op)?;
+        let path = this.read_path_from_c_str(path_scalar)?.into_owned();
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`lstat`", reject_with)?;
+            let eacc = this.eval_libc("EACCES")?;
+            this.set_last_error(eacc)?;
+            return Ok(Scalar::from_i32(-1));
+        }
+
+        let metadata = match FileMetadata::from_path(this, &path, false)? {
+            Some(metadata) => metadata,
+            None => return Ok(Scalar::from_i32(-1)), // `FileMetadata` has set errno
+        };
+
+        Ok(Scalar::from_i32(this.macos_stat_write_buf(metadata, buf_op)?))
+    }
+
+    fn macos_fstat(
+        &mut self,
+        fd_op: &OpTy<'tcx, Provenance>,
+        buf_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("macos", "fstat");
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`fstat`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return Ok(Scalar::from_i32(this.handle_not_found()?));
+        }
+
+        let metadata = match FileMetadata::from_fd(this, fd)? {
+            Some(metadata) => metadata,
+            None => return Ok(Scalar::from_i32(-1)),
+        };
+        Ok(Scalar::from_i32(this.macos_stat_write_buf(metadata, buf_op)?))
+    }
+
+    fn linux_statx(
+        &mut self,
+        dirfd_op: &OpTy<'tcx, Provenance>,    // Should be an `int`
+        pathname_op: &OpTy<'tcx, Provenance>, // Should be a `const char *`
+        flags_op: &OpTy<'tcx, Provenance>,    // Should be an `int`
+        mask_op: &OpTy<'tcx, Provenance>,     // Should be an `unsigned int`
+        statxbuf_op: &OpTy<'tcx, Provenance>, // Should be a `struct statx *`
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("linux", "statx");
+
+        let dirfd = this.read_scalar(dirfd_op)?.to_i32()?;
+        let pathname_ptr = this.read_pointer(pathname_op)?;
+        let flags = this.read_scalar(flags_op)?.to_i32()?;
+        let _mask = this.read_scalar(mask_op)?.to_u32()?;
+        let statxbuf_ptr = this.read_pointer(statxbuf_op)?;
+
+        // If the statxbuf or pathname pointers are null, the function fails with `EFAULT`.
+        if this.ptr_is_null(statxbuf_ptr)? || this.ptr_is_null(pathname_ptr)? {
+            let efault = this.eval_libc("EFAULT")?;
+            this.set_last_error(efault)?;
+            return Ok(-1);
+        }
+
+        // Under normal circumstances, we would use `deref_operand(statxbuf_op)` to produce a
+        // proper `MemPlace` and then write the results of this function to it. However, the
+        // `syscall` function is untyped. This means that all the `statx` parameters are provided
+        // as `isize`s instead of having the proper types. Thus, we have to recover the layout of
+        // `statxbuf_op` by using the `libc::statx` struct type.
+        let statxbuf = {
+            // FIXME: This long path is required because `libc::statx` is an struct and also a
+            // function and `resolve_path` is returning the latter.
+            let statx_ty = this
+                .resolve_path(&["libc", "unix", "linux_like", "linux", "gnu", "statx"])
+                .ty(*this.tcx, ty::ParamEnv::reveal_all());
+            let statx_layout = this.layout_of(statx_ty)?;
+            MPlaceTy::from_aligned_ptr(statxbuf_ptr, statx_layout)
+        };
+
+        let path = this.read_path_from_c_str(pathname_ptr)?.into_owned();
+        // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
+        let empty_path_flag = flags & this.eval_libc("AT_EMPTY_PATH")?.to_i32()? != 0;
+        // We only support:
+        // * interpreting `path` as an absolute directory,
+        // * interpreting `path` as a path relative to `dirfd` when the latter is `AT_FDCWD`, or
+        // * interpreting `dirfd` as any file descriptor when `path` is empty and AT_EMPTY_PATH is
+        // set.
+        // Other behaviors cannot be tested from `libstd` and thus are not implemented. If you
+        // found this error, please open an issue reporting it.
+        if !(path.is_absolute()
+            || dirfd == this.eval_libc_i32("AT_FDCWD")?
+            || (path.as_os_str().is_empty() && empty_path_flag))
+        {
+            throw_unsup_format!(
+                "using statx is only supported with absolute paths, relative paths with the file \
+                descriptor `AT_FDCWD`, and empty paths with the `AT_EMPTY_PATH` flag set and any \
+                file descriptor"
+            )
+        }
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`statx`", reject_with)?;
+            let ecode = if path.is_absolute() || dirfd == this.eval_libc_i32("AT_FDCWD")? {
+                // since `path` is provided, either absolute or
+                // relative to CWD, `EACCES` is the most relevant.
+                this.eval_libc("EACCES")?
+            } else {
+                // `dirfd` is set to target file, and `path` is empty
+                // (or we would have hit the `throw_unsup_format`
+                // above). `EACCES` would violate the spec.
+                assert!(empty_path_flag);
+                this.eval_libc("EBADF")?
+            };
+            this.set_last_error(ecode)?;
+            return Ok(-1);
+        }
+
+        // the `_mask_op` paramter specifies the file information that the caller requested.
+        // However `statx` is allowed to return information that was not requested or to not
+        // return information that was requested. This `mask` represents the information we can
+        // actually provide for any target.
+        let mut mask =
+            this.eval_libc("STATX_TYPE")?.to_u32()? | this.eval_libc("STATX_SIZE")?.to_u32()?;
+
+        // If the `AT_SYMLINK_NOFOLLOW` flag is set, we query the file's metadata without following
+        // symbolic links.
+        let follow_symlink = flags & this.eval_libc("AT_SYMLINK_NOFOLLOW")?.to_i32()? == 0;
+
+        // If the path is empty, and the AT_EMPTY_PATH flag is set, we query the open file
+        // represented by dirfd, whether it's a directory or otherwise.
+        let metadata = if path.as_os_str().is_empty() && empty_path_flag {
+            FileMetadata::from_fd(this, dirfd)?
+        } else {
+            FileMetadata::from_path(this, &path, follow_symlink)?
+        };
+        let metadata = match metadata {
+            Some(metadata) => metadata,
+            None => return Ok(-1),
+        };
+
+        // The `mode` field specifies the type of the file and the permissions over the file for
+        // the owner, its group and other users. Given that we can only provide the file type
+        // without using platform specific methods, we only set the bits corresponding to the file
+        // type. This should be an `__u16` but `libc` provides its values as `u32`.
+        let mode: u16 = metadata
+            .mode
+            .to_u32()?
+            .try_into()
+            .unwrap_or_else(|_| bug!("libc contains bad value for constant"));
+
+        // We need to set the corresponding bits of `mask` if the access, creation and modification
+        // times were available. Otherwise we let them be zero.
+        let (access_sec, access_nsec) = metadata
+            .accessed
+            .map(|tup| {
+                mask |= this.eval_libc("STATX_ATIME")?.to_u32()?;
+                InterpResult::Ok(tup)
+            })
+            .unwrap_or(Ok((0, 0)))?;
+
+        let (created_sec, created_nsec) = metadata
+            .created
+            .map(|tup| {
+                mask |= this.eval_libc("STATX_BTIME")?.to_u32()?;
+                InterpResult::Ok(tup)
+            })
+            .unwrap_or(Ok((0, 0)))?;
+
+        let (modified_sec, modified_nsec) = metadata
+            .modified
+            .map(|tup| {
+                mask |= this.eval_libc("STATX_MTIME")?.to_u32()?;
+                InterpResult::Ok(tup)
+            })
+            .unwrap_or(Ok((0, 0)))?;
+
+        // Now we write everything to `statxbuf`. We write a zero for the unavailable fields.
+        this.write_int_fields_named(
+            &[
+                ("stx_mask", mask.into()),
+                ("stx_blksize", 0),
+                ("stx_attributes", 0),
+                ("stx_nlink", 0),
+                ("stx_uid", 0),
+                ("stx_gid", 0),
+                ("stx_mode", mode.into()),
+                ("stx_ino", 0),
+                ("stx_size", metadata.size.into()),
+                ("stx_blocks", 0),
+                ("stx_attributes_mask", 0),
+                ("stx_rdev_major", 0),
+                ("stx_rdev_minor", 0),
+                ("stx_dev_major", 0),
+                ("stx_dev_minor", 0),
+            ],
+            &statxbuf,
+        )?;
+        #[rustfmt::skip]
+        this.write_int_fields_named(
+            &[
+                ("tv_sec", access_sec.into()),
+                ("tv_nsec", access_nsec.into()),
+            ],
+            &this.mplace_field_named(&statxbuf, "stx_atime")?,
+        )?;
+        #[rustfmt::skip]
+        this.write_int_fields_named(
+            &[
+                ("tv_sec", created_sec.into()),
+                ("tv_nsec", created_nsec.into()),
+            ],
+            &this.mplace_field_named(&statxbuf, "stx_btime")?,
+        )?;
+        #[rustfmt::skip]
+        this.write_int_fields_named(
+            &[
+                ("tv_sec", 0.into()),
+                ("tv_nsec", 0.into()),
+            ],
+            &this.mplace_field_named(&statxbuf, "stx_ctime")?,
+        )?;
+        #[rustfmt::skip]
+        this.write_int_fields_named(
+            &[
+                ("tv_sec", modified_sec.into()),
+                ("tv_nsec", modified_nsec.into()),
+            ],
+            &this.mplace_field_named(&statxbuf, "stx_mtime")?,
+        )?;
+
+        Ok(0)
+    }
+
+    fn rename(
+        &mut self,
+        oldpath_op: &OpTy<'tcx, Provenance>,
+        newpath_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let oldpath_ptr = this.read_pointer(oldpath_op)?;
+        let newpath_ptr = this.read_pointer(newpath_op)?;
+
+        if this.ptr_is_null(oldpath_ptr)? || this.ptr_is_null(newpath_ptr)? {
+            let efault = this.eval_libc("EFAULT")?;
+            this.set_last_error(efault)?;
+            return Ok(-1);
+        }
+
+        let oldpath = this.read_path_from_c_str(oldpath_ptr)?;
+        let newpath = this.read_path_from_c_str(newpath_ptr)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`rename`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        let result = rename(oldpath, newpath).map(|_| 0);
+
+        this.try_unwrap_io_result(result)
+    }
+
+    fn mkdir(
+        &mut self,
+        path_op: &OpTy<'tcx, Provenance>,
+        mode_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        #[cfg_attr(not(unix), allow(unused_variables))]
+        let mode = if this.tcx.sess.target.os == "macos" {
+            u32::from(this.read_scalar(mode_op)?.to_u16()?)
+        } else {
+            this.read_scalar(mode_op)?.to_u32()?
+        };
+
+        let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`mkdir`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        #[cfg_attr(not(unix), allow(unused_mut))]
+        let mut builder = DirBuilder::new();
+
+        // If the host supports it, forward on the mode of the directory
+        // (i.e. permission bits and the sticky bit)
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::DirBuilderExt;
+            builder.mode(mode);
+        }
+
+        let result = builder.create(path).map(|_| 0i32);
+
+        this.try_unwrap_io_result(result)
+    }
+
+    fn rmdir(&mut self, path_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`rmdir`", reject_with)?;
+            this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
+            return Ok(-1);
+        }
+
+        let result = remove_dir(path).map(|_| 0i32);
+
+        this.try_unwrap_io_result(result)
+    }
+
+    fn opendir(
+        &mut self,
+        name_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let name = this.read_path_from_c_str(this.read_pointer(name_op)?)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`opendir`", reject_with)?;
+            let eacc = this.eval_libc("EACCES")?;
+            this.set_last_error(eacc)?;
+            return Ok(Scalar::null_ptr(this));
+        }
+
+        let result = read_dir(name);
+
+        match result {
+            Ok(dir_iter) => {
+                let id = this.machine.dir_handler.insert_new(dir_iter);
+
+                // The libc API for opendir says that this method returns a pointer to an opaque
+                // structure, but we are returning an ID number. Thus, pass it as a scalar of
+                // pointer width.
+                Ok(Scalar::from_machine_usize(id, this))
+            }
+            Err(e) => {
+                this.set_last_error_from_io_error(e.kind())?;
+                Ok(Scalar::null_ptr(this))
+            }
+        }
+    }
+
+    fn linux_readdir64(
+        &mut self,
+        dirp_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("linux", "readdir64");
+
+        let dirp = this.read_scalar(dirp_op)?.to_machine_usize(this)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`readdir`", reject_with)?;
+            let eacc = this.eval_libc("EBADF")?;
+            this.set_last_error(eacc)?;
+            return Ok(Scalar::null_ptr(this));
+        }
+
+        let open_dir = this.machine.dir_handler.streams.get_mut(&dirp).ok_or_else(|| {
+            err_unsup_format!("the DIR pointer passed to readdir64 did not come from opendir")
+        })?;
+
+        let entry = match open_dir.read_dir.next() {
+            Some(Ok(dir_entry)) => {
+                // Write the directory entry into a newly allocated buffer.
+                // The name is written with write_bytes, while the rest of the
+                // dirent64 struct is written using write_int_fields.
+
+                // For reference:
+                // pub struct dirent64 {
+                //     pub d_ino: ino64_t,
+                //     pub d_off: off64_t,
+                //     pub d_reclen: c_ushort,
+                //     pub d_type: c_uchar,
+                //     pub d_name: [c_char; 256],
+                // }
+
+                let mut name = dir_entry.file_name(); // not a Path as there are no separators!
+                name.push("\0"); // Add a NUL terminator
+                let name_bytes = os_str_to_bytes(&name)?;
+                let name_len = u64::try_from(name_bytes.len()).unwrap();
+
+                let dirent64_layout = this.libc_ty_layout("dirent64")?;
+                let d_name_offset = dirent64_layout.fields.offset(4 /* d_name */).bytes();
+                let size = d_name_offset.checked_add(name_len).unwrap();
+
+                let entry =
+                    this.malloc(size, /*zero_init:*/ false, MiriMemoryKind::Runtime)?;
+
+                // If the host is a Unix system, fill in the inode number with its real value.
+                // If not, use 0 as a fallback value.
+                #[cfg(unix)]
+                let ino = std::os::unix::fs::DirEntryExt::ino(&dir_entry);
+                #[cfg(not(unix))]
+                let ino = 0u64;
+
+                let file_type = this.file_type_to_d_type(dir_entry.file_type())?;
+
+                this.write_int_fields_named(
+                    &[
+                        ("d_ino", ino.into()),
+                        ("d_off", 0),
+                        ("d_reclen", size.into()),
+                        ("d_type", file_type.into()),
+                    ],
+                    &MPlaceTy::from_aligned_ptr(entry, dirent64_layout),
+                )?;
+
+                let name_ptr = entry.offset(Size::from_bytes(d_name_offset), this)?;
+                this.write_bytes_ptr(name_ptr, name_bytes.iter().copied())?;
+
+                entry
+            }
+            None => {
+                // end of stream: return NULL
+                Pointer::null()
+            }
+            Some(Err(e)) => {
+                this.set_last_error_from_io_error(e.kind())?;
+                Pointer::null()
+            }
+        };
+
+        let open_dir = this.machine.dir_handler.streams.get_mut(&dirp).unwrap();
+        let old_entry = std::mem::replace(&mut open_dir.entry, entry);
+        this.free(old_entry, MiriMemoryKind::Runtime)?;
+
+        Ok(Scalar::from_maybe_pointer(entry, this))
+    }
+
+    fn macos_readdir_r(
+        &mut self,
+        dirp_op: &OpTy<'tcx, Provenance>,
+        entry_op: &OpTy<'tcx, Provenance>,
+        result_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        this.assert_target_os("macos", "readdir_r");
+
+        let dirp = this.read_scalar(dirp_op)?.to_machine_usize(this)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`readdir_r`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return Ok(Scalar::from_i32(this.handle_not_found()?));
+        }
+
+        let open_dir = this.machine.dir_handler.streams.get_mut(&dirp).ok_or_else(|| {
+            err_unsup_format!("the DIR pointer passed to readdir_r did not come from opendir")
+        })?;
+        Ok(Scalar::from_i32(match open_dir.read_dir.next() {
+            Some(Ok(dir_entry)) => {
+                // Write into entry, write pointer to result, return 0 on success.
+                // The name is written with write_os_str_to_c_str, while the rest of the
+                // dirent struct is written using write_int_fields.
+
+                // For reference:
+                // pub struct dirent {
+                //     pub d_ino: u64,
+                //     pub d_seekoff: u64,
+                //     pub d_reclen: u16,
+                //     pub d_namlen: u16,
+                //     pub d_type: u8,
+                //     pub d_name: [c_char; 1024],
+                // }
+
+                let entry_place = this.deref_operand(entry_op)?;
+                let name_place = this.mplace_field(&entry_place, 5)?;
+
+                let file_name = dir_entry.file_name(); // not a Path as there are no separators!
+                let (name_fits, file_name_buf_len) = this.write_os_str_to_c_str(
+                    &file_name,
+                    name_place.ptr,
+                    name_place.layout.size.bytes(),
+                )?;
+                let file_name_len = file_name_buf_len.checked_sub(1).unwrap();
+                if !name_fits {
+                    throw_unsup_format!(
+                        "a directory entry had a name too large to fit in libc::dirent"
+                    );
+                }
+
+                let entry_place = this.deref_operand(entry_op)?;
+
+                // If the host is a Unix system, fill in the inode number with its real value.
+                // If not, use 0 as a fallback value.
+                #[cfg(unix)]
+                let ino = std::os::unix::fs::DirEntryExt::ino(&dir_entry);
+                #[cfg(not(unix))]
+                let ino = 0u64;
+
+                let file_type = this.file_type_to_d_type(dir_entry.file_type())?;
+
+                this.write_int_fields_named(
+                    &[
+                        ("d_ino", ino.into()),
+                        ("d_seekoff", 0),
+                        ("d_reclen", 0),
+                        ("d_namlen", file_name_len.into()),
+                        ("d_type", file_type.into()),
+                    ],
+                    &entry_place,
+                )?;
+
+                let result_place = this.deref_operand(result_op)?;
+                this.write_scalar(this.read_scalar(entry_op)?, &result_place.into())?;
+
+                0
+            }
+            None => {
+                // end of stream: return 0, assign *result=NULL
+                this.write_null(&this.deref_operand(result_op)?.into())?;
+                0
+            }
+            Some(Err(e)) =>
+                match e.raw_os_error() {
+                    // return positive error number on error
+                    Some(error) => error,
+                    None => {
+                        throw_unsup_format!(
+                            "the error {} couldn't be converted to a return value",
+                            e
+                        )
+                    }
+                },
+        }))
+    }
+
+    fn closedir(&mut self, dirp_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let dirp = this.read_scalar(dirp_op)?.to_machine_usize(this)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`closedir`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return this.handle_not_found();
+        }
+
+        if let Some(open_dir) = this.machine.dir_handler.streams.remove(&dirp) {
+            this.free(open_dir.entry, MiriMemoryKind::Runtime)?;
+            drop(open_dir);
+            Ok(0)
+        } else {
+            this.handle_not_found()
+        }
+    }
+
+    fn ftruncate64(
+        &mut self,
+        fd_op: &OpTy<'tcx, Provenance>,
+        length_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+        let length = this.read_scalar(length_op)?.to_i64()?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`ftruncate64`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return Ok(Scalar::from_i32(this.handle_not_found()?));
+        }
+
+        Ok(Scalar::from_i32(
+            if let Some(file_descriptor) = this.machine.file_handler.handles.get_mut(&fd) {
+                // FIXME: Support ftruncate64 for all FDs
+                let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
+                if *writable {
+                    if let Ok(length) = length.try_into() {
+                        let result = file.set_len(length);
+                        this.try_unwrap_io_result(result.map(|_| 0i32))?
+                    } else {
+                        let einval = this.eval_libc("EINVAL")?;
+                        this.set_last_error(einval)?;
+                        -1
+                    }
+                } else {
+                    // The file is not writable
+                    let einval = this.eval_libc("EINVAL")?;
+                    this.set_last_error(einval)?;
+                    -1
+                }
+            } else {
+                this.handle_not_found()?
+            },
+        ))
+    }
+
+    fn fsync(&mut self, fd_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        // On macOS, `fsync` (unlike `fcntl(F_FULLFSYNC)`) does not wait for the
+        // underlying disk to finish writing. In the interest of host compatibility,
+        // we conservatively implement this with `sync_all`, which
+        // *does* wait for the disk.
+
+        let this = self.eval_context_mut();
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`fsync`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return this.handle_not_found();
+        }
+
+        if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
+            // FIXME: Support fsync for all FDs
+            let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
+            let io_result = maybe_sync_file(file, *writable, File::sync_all);
+            this.try_unwrap_io_result(io_result)
+        } else {
+            this.handle_not_found()
+        }
+    }
+
+    fn fdatasync(&mut self, fd_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`fdatasync`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return this.handle_not_found();
+        }
+
+        if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
+            // FIXME: Support fdatasync for all FDs
+            let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
+            let io_result = maybe_sync_file(file, *writable, File::sync_data);
+            this.try_unwrap_io_result(io_result)
+        } else {
+            this.handle_not_found()
+        }
+    }
+
+    fn sync_file_range(
+        &mut self,
+        fd_op: &OpTy<'tcx, Provenance>,
+        offset_op: &OpTy<'tcx, Provenance>,
+        nbytes_op: &OpTy<'tcx, Provenance>,
+        flags_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let fd = this.read_scalar(fd_op)?.to_i32()?;
+        let offset = this.read_scalar(offset_op)?.to_i64()?;
+        let nbytes = this.read_scalar(nbytes_op)?.to_i64()?;
+        let flags = this.read_scalar(flags_op)?.to_i32()?;
+
+        if offset < 0 || nbytes < 0 {
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            return Ok(Scalar::from_i32(-1));
+        }
+        let allowed_flags = this.eval_libc_i32("SYNC_FILE_RANGE_WAIT_BEFORE")?
+            | this.eval_libc_i32("SYNC_FILE_RANGE_WRITE")?
+            | this.eval_libc_i32("SYNC_FILE_RANGE_WAIT_AFTER")?;
+        if flags & allowed_flags != flags {
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            return Ok(Scalar::from_i32(-1));
+        }
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`sync_file_range`", reject_with)?;
+            // Set error code as "EBADF" (bad fd)
+            return Ok(Scalar::from_i32(this.handle_not_found()?));
+        }
+
+        if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
+            // FIXME: Support sync_data_range for all FDs
+            let FileHandle { file, writable } = file_descriptor.as_file_handle()?;
+            let io_result = maybe_sync_file(file, *writable, File::sync_data);
+            Ok(Scalar::from_i32(this.try_unwrap_io_result(io_result)?))
+        } else {
+            Ok(Scalar::from_i32(this.handle_not_found()?))
+        }
+    }
+
+    fn readlink(
+        &mut self,
+        pathname_op: &OpTy<'tcx, Provenance>,
+        buf_op: &OpTy<'tcx, Provenance>,
+        bufsize_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i64> {
+        let this = self.eval_context_mut();
+
+        let pathname = this.read_path_from_c_str(this.read_pointer(pathname_op)?)?;
+        let buf = this.read_pointer(buf_op)?;
+        let bufsize = this.read_scalar(bufsize_op)?.to_machine_usize(this)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`readlink`", reject_with)?;
+            let eacc = this.eval_libc("EACCES")?;
+            this.set_last_error(eacc)?;
+            return Ok(-1);
+        }
+
+        let result = std::fs::read_link(pathname);
+        match result {
+            Ok(resolved) => {
+                // 'readlink' truncates the resolved path if the provided buffer is not large
+                // enough, and does *not* add a null terminator. That means we cannot use the usual
+                // `write_path_to_c_str` and have to re-implement parts of it ourselves.
+                let resolved = this.convert_path_separator(
+                    Cow::Borrowed(resolved.as_ref()),
+                    crate::shims::os_str::PathConversion::HostToTarget,
+                );
+                let mut path_bytes = crate::shims::os_str::os_str_to_bytes(resolved.as_ref())?;
+                let bufsize: usize = bufsize.try_into().unwrap();
+                if path_bytes.len() > bufsize {
+                    path_bytes = &path_bytes[..bufsize]
+                }
+                this.write_bytes_ptr(buf, path_bytes.iter().copied())?;
+                Ok(path_bytes.len().try_into().unwrap())
+            }
+            Err(e) => {
+                this.set_last_error_from_io_error(e.kind())?;
+                Ok(-1)
+            }
+        }
+    }
+
+    #[cfg_attr(not(unix), allow(unused))]
+    fn isatty(&mut self, miri_fd: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        #[cfg(unix)]
+        if matches!(this.machine.isolated_op, IsolatedOp::Allow) {
+            let miri_fd = this.read_scalar(miri_fd)?.to_i32()?;
+            if let Some(host_fd) =
+                this.machine.file_handler.handles.get(&miri_fd).and_then(|fd| fd.as_unix_host_fd())
+            {
+                // "returns 1 if fd is an open file descriptor referring to a terminal;
+                // otherwise 0 is returned, and errno is set to indicate the error"
+                // SAFETY: isatty has no preconditions
+                let is_tty = unsafe { libc::isatty(host_fd) };
+                if is_tty == 0 {
+                    let errno = std::io::Error::last_os_error()
+                        .raw_os_error()
+                        .map(Scalar::from_i32)
+                        .unwrap();
+                    this.set_last_error(errno)?;
+                }
+                return Ok(is_tty);
+            }
+        }
+        // We are attemping to use a Unix interface on a non-Unix platform, or we are on a Unix
+        // platform and the passed file descriptor is not open, or isolation is enabled
+        // FIXME: It should be possible to emulate this at least on Windows by using
+        // GetConsoleMode.
+        let enotty = this.eval_libc("ENOTTY")?;
+        this.set_last_error(enotty)?;
+        Ok(0)
+    }
+
+    fn realpath(
+        &mut self,
+        path_op: &OpTy<'tcx, Provenance>,
+        processed_path_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("realpath");
+
+        let pathname = this.read_path_from_c_str(this.read_pointer(path_op)?)?;
+        let processed_ptr = this.read_pointer(processed_path_op)?;
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`realpath`", reject_with)?;
+            let eacc = this.eval_libc("EACCES")?;
+            this.set_last_error(eacc)?;
+            return Ok(Scalar::from_machine_usize(0, this));
+        }
+
+        let result = std::fs::canonicalize(pathname);
+        match result {
+            Ok(resolved) => {
+                let path_max = this
+                    .eval_libc_i32("PATH_MAX")?
+                    .try_into()
+                    .expect("PATH_MAX does not fit in u64");
+                let dest = if this.ptr_is_null(processed_ptr)? {
+                    // POSIX says behavior when passing a null pointer is implementation-defined,
+                    // but GNU/linux, freebsd, netbsd, bionic/android, and macos all treat a null pointer
+                    // similarly to:
+                    //
+                    // "If resolved_path is specified as NULL, then realpath() uses
+                    // malloc(3) to allocate a buffer of up to PATH_MAX bytes to hold
+                    // the resolved pathname, and returns a pointer to this buffer.  The
+                    // caller should deallocate this buffer using free(3)."
+                    // <https://man7.org/linux/man-pages/man3/realpath.3.html>
+                    this.alloc_path_as_c_str(&resolved, MiriMemoryKind::C.into())?
+                } else {
+                    let (wrote_path, _) =
+                        this.write_path_to_c_str(&resolved, processed_ptr, path_max)?;
+
+                    if !wrote_path {
+                        // Note that we do not explicitly handle `FILENAME_MAX`
+                        // (different from `PATH_MAX` above) as it is Linux-specific and
+                        // seems like a bit of a mess anyway: <https://eklitzke.org/path-max-is-tricky>.
+                        let enametoolong = this.eval_libc("ENAMETOOLONG")?;
+                        this.set_last_error(enametoolong)?;
+                        return Ok(Scalar::from_machine_usize(0, this));
+                    }
+                    processed_ptr
+                };
+
+                Ok(Scalar::from_maybe_pointer(dest, this))
+            }
+            Err(e) => {
+                this.set_last_error_from_io_error(e.kind())?;
+                Ok(Scalar::from_machine_usize(0, this))
+            }
+        }
+    }
+    fn mkstemp(&mut self, template_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        use rand::seq::SliceRandom;
+
+        // POSIX defines the template string.
+        const TEMPFILE_TEMPLATE_STR: &str = "XXXXXX";
+
+        let this = self.eval_context_mut();
+        this.assert_target_os_is_unix("mkstemp");
+
+        // POSIX defines the maximum number of attempts before failure.
+        //
+        // `mkstemp()` relies on `tmpnam()` which in turn relies on `TMP_MAX`.
+        // POSIX says this about `TMP_MAX`:
+        // * Minimum number of unique filenames generated by `tmpnam()`.
+        // * Maximum number of times an application can call `tmpnam()` reliably.
+        //   * The value of `TMP_MAX` is at least 25.
+        //   * On XSI-conformant systems, the value of `TMP_MAX` is at least 10000.
+        // See <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stdio.h.html>.
+        let max_attempts = this.eval_libc("TMP_MAX")?.to_u32()?;
+
+        // Get the raw bytes from the template -- as a byte slice, this is a string in the target
+        // (and the target is unix, so a byte slice is the right representation).
+        let template_ptr = this.read_pointer(template_op)?;
+        let mut template = this.eval_context_ref().read_c_str(template_ptr)?.to_owned();
+        let template_bytes = template.as_mut_slice();
+
+        // Reject if isolation is enabled.
+        if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
+            this.reject_in_isolation("`mkstemp`", reject_with)?;
+            let eacc = this.eval_libc("EACCES")?;
+            this.set_last_error(eacc)?;
+            return Ok(-1);
+        }
+
+        // Get the bytes of the suffix we expect in _target_ encoding.
+        let suffix_bytes = TEMPFILE_TEMPLATE_STR.as_bytes();
+
+        // At this point we have one `&[u8]` that represents the template and one `&[u8]`
+        // that represents the expected suffix.
+
+        // Now we figure out the index of the slice we expect to contain the suffix.
+        let start_pos = template_bytes.len().saturating_sub(suffix_bytes.len());
+        let end_pos = template_bytes.len();
+        let last_six_char_bytes = &template_bytes[start_pos..end_pos];
+
+        // If we don't find the suffix, it is an error.
+        if last_six_char_bytes != suffix_bytes {
+            let einval = this.eval_libc("EINVAL")?;
+            this.set_last_error(einval)?;
+            return Ok(-1);
+        }
+
+        // At this point we know we have 6 ASCII 'X' characters as a suffix.
+
+        // From <https://github.com/lattera/glibc/blob/895ef79e04a953cac1493863bcae29ad85657ee1/sysdeps/posix/tempname.c#L175>
+        const SUBSTITUTIONS: &[char; 62] = &[
+            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
+            'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+            'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y',
+            'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+        ];
+
+        // The file is opened with specific options, which Rust does not expose in a portable way.
+        // So we use specific APIs depending on the host OS.
+        let mut fopts = OpenOptions::new();
+        fopts.read(true).write(true).create_new(true);
+
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::OpenOptionsExt;
+            fopts.mode(0o600);
+            // Do not allow others to read or modify this file.
+            fopts.custom_flags(libc::O_EXCL);
+        }
+        #[cfg(windows)]
+        {
+            use std::os::windows::fs::OpenOptionsExt;
+            // Do not allow others to read or modify this file.
+            fopts.share_mode(0);
+        }
+
+        // If the generated file already exists, we will try again `max_attempts` many times.
+        for _ in 0..max_attempts {
+            let rng = this.machine.rng.get_mut();
+
+            // Generate a random unique suffix.
+            let unique_suffix = SUBSTITUTIONS.choose_multiple(rng, 6).collect::<String>();
+
+            // Replace the template string with the random string.
+            template_bytes[start_pos..end_pos].copy_from_slice(unique_suffix.as_bytes());
+
+            // Write the modified template back to the passed in pointer to maintain POSIX semantics.
+            this.write_bytes_ptr(template_ptr, template_bytes.iter().copied())?;
+
+            // To actually open the file, turn this into a host OsString.
+            let p = bytes_to_os_str(template_bytes)?.to_os_string();
+
+            let possibly_unique = std::env::temp_dir().join::<PathBuf>(p.into());
+
+            let file = fopts.open(&possibly_unique);
+
+            match file {
+                Ok(f) => {
+                    let fh = &mut this.machine.file_handler;
+                    let fd = fh.insert_fd(Box::new(FileHandle { file: f, writable: true }));
+                    return Ok(fd);
+                }
+                Err(e) =>
+                    match e.kind() {
+                        // If the random file already exists, keep trying.
+                        ErrorKind::AlreadyExists => continue,
+                        // Any other errors are returned to the caller.
+                        _ => {
+                            // "On error, -1 is returned, and errno is set to
+                            // indicate the error"
+                            this.set_last_error_from_io_error(e.kind())?;
+                            return Ok(-1);
+                        }
+                    },
+            }
+        }
+
+        // We ran out of attempts to create the file, return an error.
+        let eexist = this.eval_libc("EEXIST")?;
+        this.set_last_error(eexist)?;
+        Ok(-1)
+    }
+}
+
+/// Extracts the number of seconds and nanoseconds elapsed between `time` and the unix epoch when
+/// `time` is Ok. Returns `None` if `time` is an error. Fails if `time` happens before the unix
+/// epoch.
+fn extract_sec_and_nsec<'tcx>(
+    time: std::io::Result<SystemTime>,
+) -> InterpResult<'tcx, Option<(u64, u32)>> {
+    time.ok()
+        .map(|time| {
+            let duration = system_time_to_duration(&time)?;
+            Ok((duration.as_secs(), duration.subsec_nanos()))
+        })
+        .transpose()
+}
+
+/// Stores a file's metadata in order to avoid code duplication in the different metadata related
+/// shims.
+struct FileMetadata {
+    mode: Scalar<Provenance>,
+    size: u64,
+    created: Option<(u64, u32)>,
+    accessed: Option<(u64, u32)>,
+    modified: Option<(u64, u32)>,
+}
+
+impl FileMetadata {
+    fn from_path<'tcx, 'mir>(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        path: &Path,
+        follow_symlink: bool,
+    ) -> InterpResult<'tcx, Option<FileMetadata>> {
+        let metadata =
+            if follow_symlink { std::fs::metadata(path) } else { std::fs::symlink_metadata(path) };
+
+        FileMetadata::from_meta(ecx, metadata)
+    }
+
+    fn from_fd<'tcx, 'mir>(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        fd: i32,
+    ) -> InterpResult<'tcx, Option<FileMetadata>> {
+        let option = ecx.machine.file_handler.handles.get(&fd);
+        let file = match option {
+            Some(file_descriptor) => &file_descriptor.as_file_handle()?.file,
+            None => return ecx.handle_not_found().map(|_: i32| None),
+        };
+        let metadata = file.metadata();
+
+        FileMetadata::from_meta(ecx, metadata)
+    }
+
+    fn from_meta<'tcx, 'mir>(
+        ecx: &mut MiriInterpCx<'mir, 'tcx>,
+        metadata: Result<std::fs::Metadata, std::io::Error>,
+    ) -> InterpResult<'tcx, Option<FileMetadata>> {
+        let metadata = match metadata {
+            Ok(metadata) => metadata,
+            Err(e) => {
+                ecx.set_last_error_from_io_error(e.kind())?;
+                return Ok(None);
+            }
+        };
+
+        let file_type = metadata.file_type();
+
+        let mode_name = if file_type.is_file() {
+            "S_IFREG"
+        } else if file_type.is_dir() {
+            "S_IFDIR"
+        } else {
+            "S_IFLNK"
+        };
+
+        let mode = ecx.eval_libc(mode_name)?;
+
+        let size = metadata.len();
+
+        let created = extract_sec_and_nsec(metadata.created())?;
+        let accessed = extract_sec_and_nsec(metadata.accessed())?;
+        let modified = extract_sec_and_nsec(metadata.modified())?;
+
+        // FIXME: Provide more fields using platform specific methods.
+        Ok(Some(FileMetadata { mode, size, created, accessed, modified }))
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/linux/dlsym.rs b/src/tools/miri/src/shims/unix/linux/dlsym.rs
new file mode 100644
index 000000000000..a96c14c142b2
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/linux/dlsym.rs
@@ -0,0 +1,40 @@
+use rustc_middle::mir;
+
+use crate::*;
+
+#[derive(Debug, Copy, Clone)]
+pub enum Dlsym {}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        Ok(match name {
+            "__pthread_get_minstack" => None,
+            "getrandom" => None, // std falls back to syscall(SYS_getrandom, ...) when this is NULL.
+            "statx" => None,     // std falls back to syscall(SYS_statx, ...) when this is NULL.
+            _ => throw_unsup_format!("unsupported Linux dlsym: {}", name),
+        })
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        _args: &[OpTy<'tcx, Provenance>],
+        _dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let _ret = ret.expect("we don't support any diverging dlsym");
+        assert!(this.tcx.sess.target.os == "linux");
+
+        match dlsym {}
+
+        //trace!("{:?}", this.dump_place(**dest));
+        //this.go_to_block(ret);
+        //Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/linux/foreign_items.rs b/src/tools/miri/src/shims/unix/linux/foreign_items.rs
new file mode 100644
index 000000000000..5d000f9d121d
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/linux/foreign_items.rs
@@ -0,0 +1,187 @@
+use rustc_span::Symbol;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::foreign_items::EmulateByNameResult;
+use shims::unix::fs::EvalContextExt as _;
+use shims::unix::linux::sync::futex;
+use shims::unix::sync::EvalContextExt as _;
+use shims::unix::thread::EvalContextExt as _;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+
+        // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.
+
+        match link_name.as_str() {
+            // errno
+            "__errno_location" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let errno_place = this.last_error_place()?;
+                this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
+            }
+
+            // File related shims (but also see "syscall" below for statx)
+            "readdir64" => {
+                let [dirp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.linux_readdir64(dirp)?;
+                this.write_scalar(result, dest)?;
+            }
+            // Linux-only
+            "sync_file_range" => {
+                let [fd, offset, nbytes, flags] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.sync_file_range(fd, offset, nbytes, flags)?;
+                this.write_scalar(result, dest)?;
+            }
+
+            // Time related shims
+            "clock_gettime" => {
+                // This is a POSIX function but it has only been tested on linux.
+                let [clk_id, tp] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.clock_gettime(clk_id, tp)?;
+                this.write_scalar(result, dest)?;
+            }
+
+            // Threading
+            "pthread_condattr_setclock" => {
+                let [attr, clock_id] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_condattr_setclock(attr, clock_id)?;
+                this.write_scalar(result, dest)?;
+            }
+            "pthread_condattr_getclock" => {
+                let [attr, clock_id] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.pthread_condattr_getclock(attr, clock_id)?;
+                this.write_scalar(result, dest)?;
+            }
+            "pthread_setname_np" => {
+                let [thread, name] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let res =
+                    this.pthread_setname_np(this.read_scalar(thread)?, this.read_scalar(name)?)?;
+                this.write_scalar(res, dest)?;
+            }
+
+            // Dynamically invoked syscalls
+            "syscall" => {
+                // We do not use `check_shim` here because `syscall` is variadic. The argument
+                // count is checked bellow.
+                this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
+                // The syscall variadic function is legal to call with more arguments than needed,
+                // extra arguments are simply ignored. The important check is that when we use an
+                // argument, we have to also check all arguments *before* it to ensure that they
+                // have the right type.
+
+                let sys_getrandom = this.eval_libc("SYS_getrandom")?.to_machine_usize(this)?;
+
+                let sys_statx = this.eval_libc("SYS_statx")?.to_machine_usize(this)?;
+
+                let sys_futex = this.eval_libc("SYS_futex")?.to_machine_usize(this)?;
+
+                if args.is_empty() {
+                    throw_ub_format!(
+                        "incorrect number of arguments for syscall: got 0, expected at least 1"
+                    );
+                }
+                match this.read_scalar(&args[0])?.to_machine_usize(this)? {
+                    // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
+                    // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
+                    id if id == sys_getrandom => {
+                        // The first argument is the syscall id, so skip over it.
+                        if args.len() < 4 {
+                            throw_ub_format!(
+                                "incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
+                                args.len()
+                            );
+                        }
+                        getrandom(this, &args[1], &args[2], &args[3], dest)?;
+                    }
+                    // `statx` is used by `libstd` to retrieve metadata information on `linux`
+                    // instead of using `stat`,`lstat` or `fstat` as on `macos`.
+                    id if id == sys_statx => {
+                        // The first argument is the syscall id, so skip over it.
+                        if args.len() < 6 {
+                            throw_ub_format!(
+                                "incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
+                                args.len()
+                            );
+                        }
+                        let result =
+                            this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
+                        this.write_scalar(Scalar::from_machine_isize(result.into(), this), dest)?;
+                    }
+                    // `futex` is used by some synchonization primitives.
+                    id if id == sys_futex => {
+                        futex(this, &args[1..], dest)?;
+                    }
+                    id => {
+                        this.handle_unsupported(format!("can't execute syscall with ID {}", id))?;
+                        return Ok(EmulateByNameResult::AlreadyJumped);
+                    }
+                }
+            }
+
+            // Miscelanneous
+            "getrandom" => {
+                let [ptr, len, flags] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                getrandom(this, ptr, len, flags, dest)?;
+            }
+            "sched_getaffinity" => {
+                let [pid, cpusetsize, mask] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_scalar(pid)?.to_i32()?;
+                this.read_scalar(cpusetsize)?.to_machine_usize(this)?;
+                this.deref_operand(mask)?;
+                // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
+                let einval = this.eval_libc("EINVAL")?;
+                this.set_last_error(einval)?;
+                this.write_scalar(Scalar::from_i32(-1), dest)?;
+            }
+
+            // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
+            // These shims are enabled only when the caller is in the standard library.
+            "pthread_getattr_np" if this.frame_in_std() => {
+                let [_thread, _attr] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_null(dest)?;
+            }
+
+            _ => return Ok(EmulateByNameResult::NotSupported),
+        };
+
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+}
+
+// Shims the linux `getrandom` syscall.
+fn getrandom<'tcx>(
+    this: &mut MiriInterpCx<'_, 'tcx>,
+    ptr: &OpTy<'tcx, Provenance>,
+    len: &OpTy<'tcx, Provenance>,
+    flags: &OpTy<'tcx, Provenance>,
+    dest: &PlaceTy<'tcx, Provenance>,
+) -> InterpResult<'tcx> {
+    let ptr = this.read_pointer(ptr)?;
+    let len = this.read_scalar(len)?.to_machine_usize(this)?;
+
+    // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
+    // neither of which have any effect on our current PRNG.
+    // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
+    let _flags = this.read_scalar(flags)?.to_i32();
+
+    this.gen_random(ptr, len)?;
+    this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;
+    Ok(())
+}
diff --git a/src/tools/miri/src/shims/unix/linux/mod.rs b/src/tools/miri/src/shims/unix/linux/mod.rs
new file mode 100644
index 000000000000..498eb57c57fe
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/linux/mod.rs
@@ -0,0 +1,3 @@
+pub mod dlsym;
+pub mod foreign_items;
+pub mod sync;
diff --git a/src/tools/miri/src/shims/unix/linux/sync.rs b/src/tools/miri/src/shims/unix/linux/sync.rs
new file mode 100644
index 000000000000..5a6ce28d25c9
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/linux/sync.rs
@@ -0,0 +1,261 @@
+use crate::concurrency::thread::Time;
+use crate::*;
+use rustc_target::abi::{Align, Size};
+use std::time::SystemTime;
+
+/// Implementation of the SYS_futex syscall.
+/// `args` is the arguments *after* the syscall number.
+pub fn futex<'tcx>(
+    this: &mut MiriInterpCx<'_, 'tcx>,
+    args: &[OpTy<'tcx, Provenance>],
+    dest: &PlaceTy<'tcx, Provenance>,
+) -> InterpResult<'tcx> {
+    // The amount of arguments used depends on the type of futex operation.
+    // The full futex syscall takes six arguments (excluding the syscall
+    // number), which is also the maximum amount of arguments a linux syscall
+    // can take on most architectures.
+    // However, not all futex operations use all six arguments. The unused ones
+    // may or may not be left out from the `syscall()` call.
+    // Therefore we don't use `check_arg_count` here, but only check for the
+    // number of arguments to fall within a range.
+    if args.len() < 3 {
+        throw_ub_format!(
+            "incorrect number of arguments for `futex` syscall: got {}, expected at least 3",
+            args.len()
+        );
+    }
+
+    // The first three arguments (after the syscall number itself) are the same to all futex operations:
+    //     (int *addr, int op, int val).
+    // We checked above that these definitely exist.
+    let addr = this.read_immediate(&args[0])?;
+    let op = this.read_scalar(&args[1])?.to_i32()?;
+    let val = this.read_scalar(&args[2])?.to_i32()?;
+
+    let thread = this.get_active_thread();
+    let addr_scalar = addr.to_scalar();
+    let addr_usize = addr_scalar.to_machine_usize(this)?;
+
+    let futex_private = this.eval_libc_i32("FUTEX_PRIVATE_FLAG")?;
+    let futex_wait = this.eval_libc_i32("FUTEX_WAIT")?;
+    let futex_wait_bitset = this.eval_libc_i32("FUTEX_WAIT_BITSET")?;
+    let futex_wake = this.eval_libc_i32("FUTEX_WAKE")?;
+    let futex_wake_bitset = this.eval_libc_i32("FUTEX_WAKE_BITSET")?;
+    let futex_realtime = this.eval_libc_i32("FUTEX_CLOCK_REALTIME")?;
+
+    // FUTEX_PRIVATE enables an optimization that stops it from working across processes.
+    // Miri doesn't support that anyway, so we ignore that flag.
+    match op & !futex_private {
+        // FUTEX_WAIT: (int *addr, int op = FUTEX_WAIT, int val, const timespec *timeout)
+        // Blocks the thread if *addr still equals val. Wakes up when FUTEX_WAKE is called on the same address,
+        // or *timeout expires. `timeout == null` for an infinite timeout.
+        //
+        // FUTEX_WAIT_BITSET: (int *addr, int op = FUTEX_WAIT_BITSET, int val, const timespec *timeout, int *_ignored, unsigned int bitset)
+        // This is identical to FUTEX_WAIT, except:
+        //  - The timeout is absolute rather than relative.
+        //  - You can specify the bitset to selecting what WAKE operations to respond to.
+        op if op & !futex_realtime == futex_wait || op & !futex_realtime == futex_wait_bitset => {
+            let wait_bitset = op & !futex_realtime == futex_wait_bitset;
+
+            let bitset = if wait_bitset {
+                if args.len() < 6 {
+                    throw_ub_format!(
+                        "incorrect number of arguments for `futex` syscall with `op=FUTEX_WAIT_BITSET`: got {}, expected at least 6",
+                        args.len()
+                    );
+                }
+                let _timeout = this.read_pointer(&args[3])?;
+                let _uaddr2 = this.read_pointer(&args[4])?;
+                this.read_scalar(&args[5])?.to_u32()?
+            } else {
+                if args.len() < 4 {
+                    throw_ub_format!(
+                        "incorrect number of arguments for `futex` syscall with `op=FUTEX_WAIT`: got {}, expected at least 4",
+                        args.len()
+                    );
+                }
+                u32::MAX
+            };
+
+            if bitset == 0 {
+                let einval = this.eval_libc("EINVAL")?;
+                this.set_last_error(einval)?;
+                this.write_scalar(Scalar::from_machine_isize(-1, this), dest)?;
+                return Ok(());
+            }
+
+            // `deref_operand` but not actually dereferencing the ptr yet (it might be NULL!).
+            let timeout = this.ref_to_mplace(&this.read_immediate(&args[3])?)?;
+            let timeout_time = if this.ptr_is_null(timeout.ptr)? {
+                None
+            } else {
+                this.check_no_isolation(
+                    "`futex` syscall with `op=FUTEX_WAIT` and non-null timeout",
+                )?;
+                let duration = match this.read_timespec(&timeout)? {
+                    Some(duration) => duration,
+                    None => {
+                        let einval = this.eval_libc("EINVAL")?;
+                        this.set_last_error(einval)?;
+                        this.write_scalar(Scalar::from_machine_isize(-1, this), dest)?;
+                        return Ok(());
+                    }
+                };
+                Some(if wait_bitset {
+                    // FUTEX_WAIT_BITSET uses an absolute timestamp.
+                    if op & futex_realtime != 0 {
+                        Time::RealTime(SystemTime::UNIX_EPOCH.checked_add(duration).unwrap())
+                    } else {
+                        Time::Monotonic(this.machine.clock.anchor().checked_add(duration).unwrap())
+                    }
+                } else {
+                    // FUTEX_WAIT uses a relative timestamp.
+                    if op & futex_realtime != 0 {
+                        Time::RealTime(SystemTime::now().checked_add(duration).unwrap())
+                    } else {
+                        Time::Monotonic(this.machine.clock.now().checked_add(duration).unwrap())
+                    }
+                })
+            };
+            // Check the pointer for alignment and validity.
+            // The API requires `addr` to be a 4-byte aligned pointer, and will
+            // use the 4 bytes at the given address as an (atomic) i32.
+            this.check_ptr_access_align(
+                addr_scalar.to_pointer(this)?,
+                Size::from_bytes(4),
+                Align::from_bytes(4).unwrap(),
+                CheckInAllocMsg::MemoryAccessTest,
+            )?;
+            // There may be a concurrent thread changing the value of addr
+            // and then invoking the FUTEX_WAKE syscall. It is critical that the
+            // effects of this and the other thread are correctly observed,
+            // otherwise we will deadlock.
+            //
+            // There are two scenarios to consider:
+            // 1. If we (FUTEX_WAIT) execute first, we'll push ourselves into
+            //    the waiters queue and go to sleep. They (addr write & FUTEX_WAKE)
+            //    will see us in the queue and wake us up.
+            // 2. If they (addr write & FUTEX_WAKE) execute first, we must observe
+            //    addr's new value. If we see an outdated value that happens to equal
+            //    the expected val, then we'll put ourselves to sleep with no one to wake us
+            //    up, so we end up with a deadlock. This is prevented by having a SeqCst
+            //    fence inside FUTEX_WAKE syscall, and another SeqCst fence
+            //    below, the atomic read on addr after the SeqCst fence is guaranteed
+            //    not to see any value older than the addr write immediately before
+            //    calling FUTEX_WAKE. We'll see futex_val != val and return without
+            //    sleeping.
+            //
+            //    Note that the fences do not create any happens-before relationship.
+            //    The read sees the write immediately before the fence not because
+            //    one happens after the other, but is instead due to a guarantee unique
+            //    to SeqCst fences that restricts what an atomic read placed AFTER the
+            //    fence can see. The read still has to be atomic, otherwise it's a data
+            //    race. This guarantee cannot be achieved with acquire-release fences
+            //    since they only talk about reads placed BEFORE a fence - and places
+            //    no restrictions on what the read itself can see, only that there is
+            //    a happens-before between the fences IF the read happens to see the
+            //    right value. This is useless to us, since we need the read itself
+            //    to see an up-to-date value.
+            //
+            // The above case distinction is valid since both FUTEX_WAIT and FUTEX_WAKE
+            // contain a SeqCst fence, therefore inducting a total order between the operations.
+            // It is also critical that the fence, the atomic load, and the comparison in FUTEX_WAIT
+            // altogether happen atomically. If the other thread's fence in FUTEX_WAKE
+            // gets interleaved after our fence, then we lose the guarantee on the
+            // atomic load being up-to-date; if the other thread's write on addr and FUTEX_WAKE
+            // call are interleaved after the load but before the comparison, then we get a TOCTOU
+            // race condition, and go to sleep thinking the other thread will wake us up,
+            // even though they have already finished.
+            //
+            // Thankfully, preemptions cannot happen inside a Miri shim, so we do not need to
+            // do anything special to guarantee fence-load-comparison atomicity.
+            this.atomic_fence(AtomicFenceOrd::SeqCst)?;
+            // Read an `i32` through the pointer, regardless of any wrapper types.
+            // It's not uncommon for `addr` to be passed as another type than `*mut i32`, such as `*const AtomicI32`.
+            let futex_val = this
+                .read_scalar_at_offset_atomic(
+                    &addr.into(),
+                    0,
+                    this.machine.layouts.i32,
+                    AtomicReadOrd::Relaxed,
+                )?
+                .to_i32()?;
+            if val == futex_val {
+                // The value still matches, so we block the thread make it wait for FUTEX_WAKE.
+                this.block_thread(thread);
+                this.futex_wait(addr_usize, thread, bitset);
+                // Succesfully waking up from FUTEX_WAIT always returns zero.
+                this.write_scalar(Scalar::from_machine_isize(0, this), dest)?;
+                // Register a timeout callback if a timeout was specified.
+                // This callback will override the return value when the timeout triggers.
+                if let Some(timeout_time) = timeout_time {
+                    let dest = dest.clone();
+                    this.register_timeout_callback(
+                        thread,
+                        timeout_time,
+                        Box::new(move |this| {
+                            this.unblock_thread(thread);
+                            this.futex_remove_waiter(addr_usize, thread);
+                            let etimedout = this.eval_libc("ETIMEDOUT")?;
+                            this.set_last_error(etimedout)?;
+                            this.write_scalar(Scalar::from_machine_isize(-1, this), &dest)?;
+                            Ok(())
+                        }),
+                    );
+                }
+            } else {
+                // The futex value doesn't match the expected value, so we return failure
+                // right away without sleeping: -1 and errno set to EAGAIN.
+                let eagain = this.eval_libc("EAGAIN")?;
+                this.set_last_error(eagain)?;
+                this.write_scalar(Scalar::from_machine_isize(-1, this), dest)?;
+            }
+        }
+        // FUTEX_WAKE: (int *addr, int op = FUTEX_WAKE, int val)
+        // Wakes at most `val` threads waiting on the futex at `addr`.
+        // Returns the amount of threads woken up.
+        // Does not access the futex value at *addr.
+        // FUTEX_WAKE_BITSET: (int *addr, int op = FUTEX_WAKE, int val, const timespect *_unused, int *_unused, unsigned int bitset)
+        // Same as FUTEX_WAKE, but allows you to specify a bitset to select which threads to wake up.
+        op if op == futex_wake || op == futex_wake_bitset => {
+            let bitset = if op == futex_wake_bitset {
+                if args.len() < 6 {
+                    throw_ub_format!(
+                        "incorrect number of arguments for `futex` syscall with `op=FUTEX_WAKE_BITSET`: got {}, expected at least 6",
+                        args.len()
+                    );
+                }
+                let _timeout = this.read_pointer(&args[3])?;
+                let _uaddr2 = this.read_pointer(&args[4])?;
+                this.read_scalar(&args[5])?.to_u32()?
+            } else {
+                u32::MAX
+            };
+            if bitset == 0 {
+                let einval = this.eval_libc("EINVAL")?;
+                this.set_last_error(einval)?;
+                this.write_scalar(Scalar::from_machine_isize(-1, this), dest)?;
+                return Ok(());
+            }
+            // Together with the SeqCst fence in futex_wait, this makes sure that futex_wait
+            // will see the latest value on addr which could be changed by our caller
+            // before doing the syscall.
+            this.atomic_fence(AtomicFenceOrd::SeqCst)?;
+            let mut n = 0;
+            #[allow(clippy::integer_arithmetic)]
+            for _ in 0..val {
+                if let Some(thread) = this.futex_wake(addr_usize, bitset) {
+                    this.unblock_thread(thread);
+                    this.unregister_timeout_callback_if_exists(thread);
+                    n += 1;
+                } else {
+                    break;
+                }
+            }
+            this.write_scalar(Scalar::from_machine_isize(n, this), dest)?;
+        }
+        op => throw_unsup_format!("Miri does not support `futex` syscall with op={}", op),
+    }
+
+    Ok(())
+}
diff --git a/src/tools/miri/src/shims/unix/macos/dlsym.rs b/src/tools/miri/src/shims/unix/macos/dlsym.rs
new file mode 100644
index 000000000000..18804b45efca
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/macos/dlsym.rs
@@ -0,0 +1,52 @@
+use rustc_middle::mir;
+
+use log::trace;
+
+use crate::*;
+use helpers::check_arg_count;
+
+#[derive(Debug, Copy, Clone)]
+#[allow(non_camel_case_types)]
+pub enum Dlsym {
+    getentropy,
+}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        Ok(match name {
+            "getentropy" => Some(Dlsym::getentropy),
+            _ => throw_unsup_format!("unsupported macOS dlsym: {}", name),
+        })
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let ret = ret.expect("we don't support any diverging dlsym");
+        assert!(this.tcx.sess.target.os == "macos");
+
+        match dlsym {
+            Dlsym::getentropy => {
+                let [ptr, len] = check_arg_count(args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let len = this.read_scalar(len)?.to_machine_usize(this)?;
+                this.gen_random(ptr, len)?;
+                this.write_null(dest)?;
+            }
+        }
+
+        trace!("{:?}", this.dump_place(**dest));
+        this.go_to_block(ret);
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/macos/foreign_items.rs b/src/tools/miri/src/shims/unix/macos/foreign_items.rs
new file mode 100644
index 000000000000..38d791fba98a
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/macos/foreign_items.rs
@@ -0,0 +1,197 @@
+use rustc_span::Symbol;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::foreign_items::EmulateByNameResult;
+use shims::unix::fs::EvalContextExt as _;
+use shims::unix::thread::EvalContextExt as _;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+
+        // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.
+
+        match link_name.as_str() {
+            // errno
+            "__error" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let errno_place = this.last_error_place()?;
+                this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
+            }
+
+            // File related shims
+            "close$NOCANCEL" => {
+                let [result] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.close(result)?;
+                this.write_scalar(result, dest)?;
+            }
+            "stat" | "stat64" | "stat$INODE64" => {
+                let [path, buf] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.macos_stat(path, buf)?;
+                this.write_scalar(result, dest)?;
+            }
+            "lstat" | "lstat64" | "lstat$INODE64" => {
+                let [path, buf] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.macos_lstat(path, buf)?;
+                this.write_scalar(result, dest)?;
+            }
+            "fstat" | "fstat64" | "fstat$INODE64" => {
+                let [fd, buf] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.macos_fstat(fd, buf)?;
+                this.write_scalar(result, dest)?;
+            }
+            "opendir$INODE64" => {
+                let [name] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.opendir(name)?;
+                this.write_scalar(result, dest)?;
+            }
+            "readdir_r" | "readdir_r$INODE64" => {
+                let [dirp, entry, result] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.macos_readdir_r(dirp, entry, result)?;
+                this.write_scalar(result, dest)?;
+            }
+            "lseek" => {
+                let [fd, offset, whence] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // macOS is 64bit-only, so this is lseek64
+                let result = this.lseek64(fd, offset, whence)?;
+                this.write_scalar(result, dest)?;
+            }
+            "ftruncate" => {
+                let [fd, length] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                // macOS is 64bit-only, so this is ftruncate64
+                let result = this.ftruncate64(fd, length)?;
+                this.write_scalar(result, dest)?;
+            }
+            "realpath$DARWIN_EXTSN" => {
+                let [path, resolved_path] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.realpath(path, resolved_path)?;
+                this.write_scalar(result, dest)?;
+            }
+
+            // Environment related shims
+            "_NSGetEnviron" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_pointer(
+                    this.machine.env_vars.environ.expect("machine must be initialized").ptr,
+                    dest,
+                )?;
+            }
+
+            // Time related shims
+            "mach_absolute_time" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.mach_absolute_time()?;
+                this.write_scalar(result, dest)?;
+            }
+
+            "mach_timebase_info" => {
+                let [info] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let result = this.mach_timebase_info(info)?;
+                this.write_scalar(result, dest)?;
+            }
+
+            // Access to command-line arguments
+            "_NSGetArgc" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_pointer(
+                    this.machine.argc.expect("machine must be initialized").ptr,
+                    dest,
+                )?;
+            }
+            "_NSGetArgv" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.write_pointer(
+                    this.machine.argv.expect("machine must be initialized").ptr,
+                    dest,
+                )?;
+            }
+            "_NSGetExecutablePath" => {
+                let [buf, bufsize] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.check_no_isolation("`_NSGetExecutablePath`")?;
+
+                let buf_ptr = this.read_pointer(buf)?;
+                let bufsize = this.deref_operand(bufsize)?;
+
+                // Using the host current_exe is a bit off, but consistent with Linux
+                // (where stdlib reads /proc/self/exe).
+                let path = std::env::current_exe().unwrap();
+                let (written, size_needed) = this.write_path_to_c_str(
+                    &path,
+                    buf_ptr,
+                    this.read_scalar(&bufsize.into())?.to_u32()?.into(),
+                )?;
+
+                if written {
+                    this.write_null(dest)?;
+                } else {
+                    this.write_scalar(
+                        Scalar::from_u32(size_needed.try_into().unwrap()),
+                        &bufsize.into(),
+                    )?;
+                    this.write_int(-1, dest)?;
+                }
+            }
+
+            // Thread-local storage
+            "_tlv_atexit" => {
+                let [dtor, data] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let dtor = this.read_pointer(dtor)?;
+                let dtor = this.get_ptr_fn(dtor)?.as_instance()?;
+                let data = this.read_scalar(data)?;
+                let active_thread = this.get_active_thread();
+                this.machine.tls.set_macos_thread_dtor(active_thread, dtor, data)?;
+            }
+
+            // Querying system information
+            "pthread_get_stackaddr_np" => {
+                let [thread] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_scalar(thread)?.to_machine_usize(this)?;
+                let stack_addr = Scalar::from_uint(STACK_ADDR, this.pointer_size());
+                this.write_scalar(stack_addr, dest)?;
+            }
+            "pthread_get_stacksize_np" => {
+                let [thread] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                this.read_scalar(thread)?.to_machine_usize(this)?;
+                let stack_size = Scalar::from_uint(STACK_SIZE, this.pointer_size());
+                this.write_scalar(stack_size, dest)?;
+            }
+
+            // Threading
+            "pthread_setname_np" => {
+                let [name] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let thread = this.pthread_self()?;
+                this.pthread_setname_np(thread, this.read_scalar(name)?)?;
+            }
+
+            // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
+            // These shims are enabled only when the caller is in the standard library.
+            "mmap" if this.frame_in_std() => {
+                // This is a horrible hack, but since the guard page mechanism calls mmap and expects a particular return value, we just give it that value.
+                let [addr, _, _, _, _, _] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let addr = this.read_scalar(addr)?;
+                this.write_scalar(addr, dest)?;
+            }
+
+            _ => return Ok(EmulateByNameResult::NotSupported),
+        };
+
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+}
diff --git a/src/tools/miri/src/shims/unix/macos/mod.rs b/src/tools/miri/src/shims/unix/macos/mod.rs
new file mode 100644
index 000000000000..434f5f30b5a5
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/macos/mod.rs
@@ -0,0 +1,2 @@
+pub mod dlsym;
+pub mod foreign_items;
diff --git a/src/tools/miri/src/shims/unix/mod.rs b/src/tools/miri/src/shims/unix/mod.rs
new file mode 100644
index 000000000000..6fefb054f3c0
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/mod.rs
@@ -0,0 +1,16 @@
+pub mod dlsym;
+pub mod foreign_items;
+
+mod fs;
+mod sync;
+mod thread;
+
+mod android;
+mod freebsd;
+mod linux;
+mod macos;
+
+pub use fs::{DirHandler, FileHandler};
+
+// Make up some constants.
+const UID: u32 = 1000;
diff --git a/src/tools/miri/src/shims/unix/sync.rs b/src/tools/miri/src/shims/unix/sync.rs
new file mode 100644
index 000000000000..2e972a27ffeb
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/sync.rs
@@ -0,0 +1,907 @@
+use std::time::SystemTime;
+
+use rustc_hir::LangItem;
+use rustc_middle::ty::{layout::TyAndLayout, query::TyCtxtAt, Ty};
+
+use crate::concurrency::thread::Time;
+use crate::*;
+
+// pthread_mutexattr_t is either 4 or 8 bytes, depending on the platform.
+
+// Our chosen memory layout for emulation (does not have to match the platform layout!):
+// store an i32 in the first four bytes equal to the corresponding libc mutex kind constant
+// (e.g. PTHREAD_MUTEX_NORMAL).
+
+/// A flag that allows to distinguish `PTHREAD_MUTEX_NORMAL` from
+/// `PTHREAD_MUTEX_DEFAULT`. Since in `glibc` they have the same numeric values,
+/// but different behaviour, we need a way to distinguish them. We do this by
+/// setting this bit flag to the `PTHREAD_MUTEX_NORMAL` mutexes. See the comment
+/// in `pthread_mutexattr_settype` function.
+const PTHREAD_MUTEX_NORMAL_FLAG: i32 = 0x8000000;
+
+fn is_mutex_kind_default<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    kind: Scalar<Provenance>,
+) -> InterpResult<'tcx, bool> {
+    Ok(kind == ecx.eval_libc("PTHREAD_MUTEX_DEFAULT")?)
+}
+
+fn is_mutex_kind_normal<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    kind: Scalar<Provenance>,
+) -> InterpResult<'tcx, bool> {
+    let kind = kind.to_i32()?;
+    let mutex_normal_kind = ecx.eval_libc("PTHREAD_MUTEX_NORMAL")?.to_i32()?;
+    Ok(kind == (mutex_normal_kind | PTHREAD_MUTEX_NORMAL_FLAG))
+}
+
+fn mutexattr_get_kind<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    attr_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    ecx.read_scalar_at_offset(attr_op, 0, ecx.machine.layouts.i32)
+}
+
+fn mutexattr_set_kind<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    attr_op: &OpTy<'tcx, Provenance>,
+    kind: impl Into<Scalar<Provenance>>,
+) -> InterpResult<'tcx, ()> {
+    ecx.write_scalar_at_offset(attr_op, 0, kind, layout_of_maybe_uninit(ecx.tcx, ecx.tcx.types.i32))
+}
+
+// pthread_mutex_t is between 24 and 48 bytes, depending on the platform.
+
+// Our chosen memory layout for the emulated mutex (does not have to match the platform layout!):
+// bytes 0-3: reserved for signature on macOS
+// (need to avoid this because it is set by static initializer macros)
+// bytes 4-7: mutex id as u32 or 0 if id is not assigned yet.
+// bytes 12-15 or 16-19 (depending on platform): mutex kind, as an i32
+// (the kind has to be at its offset for compatibility with static initializer macros)
+
+fn mutex_get_kind<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    mutex_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    let offset = if ecx.pointer_size().bytes() == 8 { 16 } else { 12 };
+    ecx.read_scalar_at_offset_atomic(
+        mutex_op,
+        offset,
+        ecx.machine.layouts.i32,
+        AtomicReadOrd::Relaxed,
+    )
+}
+
+fn mutex_set_kind<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    mutex_op: &OpTy<'tcx, Provenance>,
+    kind: impl Into<Scalar<Provenance>>,
+) -> InterpResult<'tcx, ()> {
+    let offset = if ecx.pointer_size().bytes() == 8 { 16 } else { 12 };
+    ecx.write_scalar_at_offset_atomic(
+        mutex_op,
+        offset,
+        kind,
+        layout_of_maybe_uninit(ecx.tcx, ecx.tcx.types.i32),
+        AtomicWriteOrd::Relaxed,
+    )
+}
+
+fn mutex_get_id<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    mutex_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    ecx.read_scalar_at_offset_atomic(mutex_op, 4, ecx.machine.layouts.u32, AtomicReadOrd::Relaxed)
+}
+
+fn mutex_set_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    mutex_op: &OpTy<'tcx, Provenance>,
+    id: impl Into<Scalar<Provenance>>,
+) -> InterpResult<'tcx, ()> {
+    ecx.write_scalar_at_offset_atomic(
+        mutex_op,
+        4,
+        id,
+        layout_of_maybe_uninit(ecx.tcx, ecx.tcx.types.u32),
+        AtomicWriteOrd::Relaxed,
+    )
+}
+
+fn mutex_get_or_create_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    mutex_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, MutexId> {
+    let value_place = ecx.deref_operand_and_offset(mutex_op, 4, ecx.machine.layouts.u32)?;
+
+    ecx.mutex_get_or_create(|ecx, next_id| {
+        let (old, success) = ecx
+            .atomic_compare_exchange_scalar(
+                &value_place,
+                &ImmTy::from_uint(0u32, ecx.machine.layouts.u32),
+                next_id.to_u32_scalar(),
+                AtomicRwOrd::Relaxed,
+                AtomicReadOrd::Relaxed,
+                false,
+            )?
+            .to_scalar_pair();
+
+        Ok(if success.to_bool().expect("compare_exchange's second return value is a bool") {
+            // Caller of the closure needs to allocate next_id
+            None
+        } else {
+            Some(MutexId::from_u32(old.to_u32().expect("layout is u32")))
+        })
+    })
+}
+
+// pthread_rwlock_t is between 32 and 56 bytes, depending on the platform.
+
+// Our chosen memory layout for the emulated rwlock (does not have to match the platform layout!):
+// bytes 0-3: reserved for signature on macOS
+// (need to avoid this because it is set by static initializer macros)
+// bytes 4-7: rwlock id as u32 or 0 if id is not assigned yet.
+
+fn rwlock_get_id<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    rwlock_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    ecx.read_scalar_at_offset_atomic(rwlock_op, 4, ecx.machine.layouts.u32, AtomicReadOrd::Relaxed)
+}
+
+fn rwlock_get_or_create_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    rwlock_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, RwLockId> {
+    let value_place = ecx.deref_operand_and_offset(rwlock_op, 4, ecx.machine.layouts.u32)?;
+
+    ecx.rwlock_get_or_create(|ecx, next_id| {
+        let (old, success) = ecx
+            .atomic_compare_exchange_scalar(
+                &value_place,
+                &ImmTy::from_uint(0u32, ecx.machine.layouts.u32),
+                next_id.to_u32_scalar(),
+                AtomicRwOrd::Relaxed,
+                AtomicReadOrd::Relaxed,
+                false,
+            )?
+            .to_scalar_pair();
+
+        Ok(if success.to_bool().expect("compare_exchange's second return value is a bool") {
+            // Caller of the closure needs to allocate next_id
+            None
+        } else {
+            Some(RwLockId::from_u32(old.to_u32().expect("layout is u32")))
+        })
+    })
+}
+
+// pthread_condattr_t
+
+// Our chosen memory layout for emulation (does not have to match the platform layout!):
+// store an i32 in the first four bytes equal to the corresponding libc clock id constant
+// (e.g. CLOCK_REALTIME).
+
+fn condattr_get_clock_id<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    attr_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    ecx.read_scalar_at_offset(attr_op, 0, ecx.machine.layouts.i32)
+}
+
+fn condattr_set_clock_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    attr_op: &OpTy<'tcx, Provenance>,
+    clock_id: impl Into<Scalar<Provenance>>,
+) -> InterpResult<'tcx, ()> {
+    ecx.write_scalar_at_offset(
+        attr_op,
+        0,
+        clock_id,
+        layout_of_maybe_uninit(ecx.tcx, ecx.machine.layouts.i32.ty),
+    )
+}
+
+// pthread_cond_t
+
+// Our chosen memory layout for the emulated conditional variable (does not have
+// to match the platform layout!):
+
+// bytes 0-3: reserved for signature on macOS
+// bytes 4-7: the conditional variable id as u32 or 0 if id is not assigned yet.
+// bytes 8-11: the clock id constant as i32
+
+fn cond_get_id<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    cond_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    ecx.read_scalar_at_offset_atomic(cond_op, 4, ecx.machine.layouts.u32, AtomicReadOrd::Relaxed)
+}
+
+fn cond_set_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    cond_op: &OpTy<'tcx, Provenance>,
+    id: impl Into<Scalar<Provenance>>,
+) -> InterpResult<'tcx, ()> {
+    ecx.write_scalar_at_offset_atomic(
+        cond_op,
+        4,
+        id,
+        layout_of_maybe_uninit(ecx.tcx, ecx.tcx.types.u32),
+        AtomicWriteOrd::Relaxed,
+    )
+}
+
+fn cond_get_or_create_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    cond_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, CondvarId> {
+    let value_place = ecx.deref_operand_and_offset(cond_op, 4, ecx.machine.layouts.u32)?;
+
+    ecx.condvar_get_or_create(|ecx, next_id| {
+        let (old, success) = ecx
+            .atomic_compare_exchange_scalar(
+                &value_place,
+                &ImmTy::from_uint(0u32, ecx.machine.layouts.u32),
+                next_id.to_u32_scalar(),
+                AtomicRwOrd::Relaxed,
+                AtomicReadOrd::Relaxed,
+                false,
+            )?
+            .to_scalar_pair();
+
+        Ok(if success.to_bool().expect("compare_exchange's second return value is a bool") {
+            // Caller of the closure needs to allocate next_id
+            None
+        } else {
+            Some(CondvarId::from_u32(old.to_u32().expect("layout is u32")))
+        })
+    })
+}
+
+fn cond_get_clock_id<'mir, 'tcx: 'mir>(
+    ecx: &MiriInterpCx<'mir, 'tcx>,
+    cond_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, Scalar<Provenance>> {
+    ecx.read_scalar_at_offset(cond_op, 8, ecx.machine.layouts.i32)
+}
+
+fn cond_set_clock_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    cond_op: &OpTy<'tcx, Provenance>,
+    clock_id: impl Into<Scalar<Provenance>>,
+) -> InterpResult<'tcx, ()> {
+    ecx.write_scalar_at_offset(
+        cond_op,
+        8,
+        clock_id,
+        layout_of_maybe_uninit(ecx.tcx, ecx.tcx.types.i32),
+    )
+}
+
+/// Try to reacquire the mutex associated with the condition variable after we
+/// were signaled.
+fn reacquire_cond_mutex<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    thread: ThreadId,
+    mutex: MutexId,
+) -> InterpResult<'tcx> {
+    ecx.unblock_thread(thread);
+    if ecx.mutex_is_locked(mutex) {
+        ecx.mutex_enqueue_and_block(mutex, thread);
+    } else {
+        ecx.mutex_lock(mutex, thread);
+    }
+    Ok(())
+}
+
+/// After a thread waiting on a condvar was signalled:
+/// Reacquire the conditional variable and remove the timeout callback if any
+/// was registered.
+fn post_cond_signal<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    thread: ThreadId,
+    mutex: MutexId,
+) -> InterpResult<'tcx> {
+    reacquire_cond_mutex(ecx, thread, mutex)?;
+    // Waiting for the mutex is not included in the waiting time because we need
+    // to acquire the mutex always even if we get a timeout.
+    ecx.unregister_timeout_callback_if_exists(thread);
+    Ok(())
+}
+
+/// Release the mutex associated with the condition variable because we are
+/// entering the waiting state.
+fn release_cond_mutex_and_block<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    active_thread: ThreadId,
+    mutex: MutexId,
+) -> InterpResult<'tcx> {
+    if let Some(old_locked_count) = ecx.mutex_unlock(mutex, active_thread) {
+        if old_locked_count != 1 {
+            throw_unsup_format!("awaiting on a lock acquired multiple times is not supported");
+        }
+    } else {
+        throw_ub_format!("awaiting on unlocked or owned by a different thread mutex");
+    }
+    ecx.block_thread(active_thread);
+    Ok(())
+}
+
+impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn pthread_mutexattr_init(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let default_kind = this.eval_libc("PTHREAD_MUTEX_DEFAULT")?;
+        mutexattr_set_kind(this, attr_op, default_kind)?;
+
+        Ok(0)
+    }
+
+    fn pthread_mutexattr_settype(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+        kind_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let kind = this.read_scalar(kind_op)?;
+        if kind == this.eval_libc("PTHREAD_MUTEX_NORMAL")? {
+            // In `glibc` implementation, the numeric values of
+            // `PTHREAD_MUTEX_NORMAL` and `PTHREAD_MUTEX_DEFAULT` are equal.
+            // However, a mutex created by explicitly passing
+            // `PTHREAD_MUTEX_NORMAL` type has in some cases different behaviour
+            // from the default mutex for which the type was not explicitly
+            // specified. For a more detailed discussion, please see
+            // https://github.com/rust-lang/miri/issues/1419.
+            //
+            // To distinguish these two cases in already constructed mutexes, we
+            // use the same trick as glibc: for the case when
+            // `pthread_mutexattr_settype` is caled explicitly, we set the
+            // `PTHREAD_MUTEX_NORMAL_FLAG` flag.
+            let normal_kind = kind.to_i32()? | PTHREAD_MUTEX_NORMAL_FLAG;
+            // Check that after setting the flag, the kind is distinguishable
+            // from all other kinds.
+            assert_ne!(normal_kind, this.eval_libc("PTHREAD_MUTEX_DEFAULT")?.to_i32()?);
+            assert_ne!(normal_kind, this.eval_libc("PTHREAD_MUTEX_ERRORCHECK")?.to_i32()?);
+            assert_ne!(normal_kind, this.eval_libc("PTHREAD_MUTEX_RECURSIVE")?.to_i32()?);
+            mutexattr_set_kind(this, attr_op, Scalar::from_i32(normal_kind))?;
+        } else if kind == this.eval_libc("PTHREAD_MUTEX_DEFAULT")?
+            || kind == this.eval_libc("PTHREAD_MUTEX_ERRORCHECK")?
+            || kind == this.eval_libc("PTHREAD_MUTEX_RECURSIVE")?
+        {
+            mutexattr_set_kind(this, attr_op, kind)?;
+        } else {
+            let einval = this.eval_libc_i32("EINVAL")?;
+            return Ok(einval);
+        }
+
+        Ok(0)
+    }
+
+    fn pthread_mutexattr_destroy(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        // Destroying an uninit pthread_mutexattr is UB, so check to make sure it's not uninit.
+        mutexattr_get_kind(this, attr_op)?;
+
+        // To catch double-destroys, we de-initialize the mutexattr.
+        // This is technically not right and might lead to false positives. For example, the below
+        // code is *likely* sound, even assuming uninit numbers are UB, but Miri complains.
+        //
+        // let mut x: MaybeUninit<libc::pthread_mutexattr_t> = MaybeUninit::zeroed();
+        // libc::pthread_mutexattr_init(x.as_mut_ptr());
+        // libc::pthread_mutexattr_destroy(x.as_mut_ptr());
+        // x.assume_init();
+        //
+        // However, the way libstd uses the pthread APIs works in our favor here, so we can get away with this.
+        // This can always be revisited to have some external state to catch double-destroys
+        // but not complain about the above code. See https://github.com/rust-lang/miri/pull/1933
+        this.write_uninit(&this.deref_operand(attr_op)?.into())?;
+
+        Ok(0)
+    }
+
+    fn pthread_mutex_init(
+        &mut self,
+        mutex_op: &OpTy<'tcx, Provenance>,
+        attr_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let attr = this.read_pointer(attr_op)?;
+        let kind = if this.ptr_is_null(attr)? {
+            this.eval_libc("PTHREAD_MUTEX_DEFAULT")?
+        } else {
+            mutexattr_get_kind(this, attr_op)?
+        };
+
+        // Write 0 to use the same code path as the static initializers.
+        mutex_set_id(this, mutex_op, Scalar::from_i32(0))?;
+
+        mutex_set_kind(this, mutex_op, kind)?;
+
+        Ok(0)
+    }
+
+    fn pthread_mutex_lock(&mut self, mutex_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let kind = mutex_get_kind(this, mutex_op)?;
+        let id = mutex_get_or_create_id(this, mutex_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.mutex_is_locked(id) {
+            let owner_thread = this.mutex_get_owner(id);
+            if owner_thread != active_thread {
+                // Enqueue the active thread.
+                this.mutex_enqueue_and_block(id, active_thread);
+                Ok(0)
+            } else {
+                // Trying to acquire the same mutex again.
+                if is_mutex_kind_default(this, kind)? {
+                    throw_ub_format!("trying to acquire already locked default mutex");
+                } else if is_mutex_kind_normal(this, kind)? {
+                    throw_machine_stop!(TerminationInfo::Deadlock);
+                } else if kind == this.eval_libc("PTHREAD_MUTEX_ERRORCHECK")? {
+                    this.eval_libc_i32("EDEADLK")
+                } else if kind == this.eval_libc("PTHREAD_MUTEX_RECURSIVE")? {
+                    this.mutex_lock(id, active_thread);
+                    Ok(0)
+                } else {
+                    throw_unsup_format!(
+                        "called pthread_mutex_lock on an unsupported type of mutex"
+                    );
+                }
+            }
+        } else {
+            // The mutex is unlocked. Let's lock it.
+            this.mutex_lock(id, active_thread);
+            Ok(0)
+        }
+    }
+
+    fn pthread_mutex_trylock(
+        &mut self,
+        mutex_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let kind = mutex_get_kind(this, mutex_op)?;
+        let id = mutex_get_or_create_id(this, mutex_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.mutex_is_locked(id) {
+            let owner_thread = this.mutex_get_owner(id);
+            if owner_thread != active_thread {
+                this.eval_libc_i32("EBUSY")
+            } else {
+                if is_mutex_kind_default(this, kind)?
+                    || is_mutex_kind_normal(this, kind)?
+                    || kind == this.eval_libc("PTHREAD_MUTEX_ERRORCHECK")?
+                {
+                    this.eval_libc_i32("EBUSY")
+                } else if kind == this.eval_libc("PTHREAD_MUTEX_RECURSIVE")? {
+                    this.mutex_lock(id, active_thread);
+                    Ok(0)
+                } else {
+                    throw_unsup_format!(
+                        "called pthread_mutex_trylock on an unsupported type of mutex"
+                    );
+                }
+            }
+        } else {
+            // The mutex is unlocked. Let's lock it.
+            this.mutex_lock(id, active_thread);
+            Ok(0)
+        }
+    }
+
+    fn pthread_mutex_unlock(
+        &mut self,
+        mutex_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let kind = mutex_get_kind(this, mutex_op)?;
+        let id = mutex_get_or_create_id(this, mutex_op)?;
+        let active_thread = this.get_active_thread();
+
+        if let Some(_old_locked_count) = this.mutex_unlock(id, active_thread) {
+            // The mutex was locked by the current thread.
+            Ok(0)
+        } else {
+            // The mutex was locked by another thread or not locked at all. See
+            // the “Unlock When Not Owner” column in
+            // https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutex_unlock.html.
+            if is_mutex_kind_default(this, kind)? {
+                throw_ub_format!(
+                    "unlocked a default mutex that was not locked by the current thread"
+                );
+            } else if is_mutex_kind_normal(this, kind)? {
+                throw_ub_format!(
+                    "unlocked a PTHREAD_MUTEX_NORMAL mutex that was not locked by the current thread"
+                );
+            } else if kind == this.eval_libc("PTHREAD_MUTEX_ERRORCHECK")?
+                || kind == this.eval_libc("PTHREAD_MUTEX_RECURSIVE")?
+            {
+                this.eval_libc_i32("EPERM")
+            } else {
+                throw_unsup_format!("called pthread_mutex_unlock on an unsupported type of mutex");
+            }
+        }
+    }
+
+    fn pthread_mutex_destroy(
+        &mut self,
+        mutex_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = mutex_get_or_create_id(this, mutex_op)?;
+
+        if this.mutex_is_locked(id) {
+            throw_ub_format!("destroyed a locked mutex");
+        }
+
+        // Destroying an uninit pthread_mutex is UB, so check to make sure it's not uninit.
+        mutex_get_kind(this, mutex_op)?;
+        mutex_get_id(this, mutex_op)?;
+
+        // This might lead to false positives, see comment in pthread_mutexattr_destroy
+        this.write_uninit(&this.deref_operand(mutex_op)?.into())?;
+        // FIXME: delete interpreter state associated with this mutex.
+
+        Ok(0)
+    }
+
+    fn pthread_rwlock_rdlock(
+        &mut self,
+        rwlock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = rwlock_get_or_create_id(this, rwlock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_write_locked(id) {
+            this.rwlock_enqueue_and_block_reader(id, active_thread);
+            Ok(0)
+        } else {
+            this.rwlock_reader_lock(id, active_thread);
+            Ok(0)
+        }
+    }
+
+    fn pthread_rwlock_tryrdlock(
+        &mut self,
+        rwlock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = rwlock_get_or_create_id(this, rwlock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_write_locked(id) {
+            this.eval_libc_i32("EBUSY")
+        } else {
+            this.rwlock_reader_lock(id, active_thread);
+            Ok(0)
+        }
+    }
+
+    fn pthread_rwlock_wrlock(
+        &mut self,
+        rwlock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = rwlock_get_or_create_id(this, rwlock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_locked(id) {
+            // Note: this will deadlock if the lock is already locked by this
+            // thread in any way.
+            //
+            // Relevant documentation:
+            // https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_rwlock_wrlock.html
+            // An in-depth discussion on this topic:
+            // https://github.com/rust-lang/rust/issues/53127
+            //
+            // FIXME: Detect and report the deadlock proactively. (We currently
+            // report the deadlock only when no thread can continue execution,
+            // but we could detect that this lock is already locked and report
+            // an error.)
+            this.rwlock_enqueue_and_block_writer(id, active_thread);
+        } else {
+            this.rwlock_writer_lock(id, active_thread);
+        }
+
+        Ok(0)
+    }
+
+    fn pthread_rwlock_trywrlock(
+        &mut self,
+        rwlock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = rwlock_get_or_create_id(this, rwlock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_locked(id) {
+            this.eval_libc_i32("EBUSY")
+        } else {
+            this.rwlock_writer_lock(id, active_thread);
+            Ok(0)
+        }
+    }
+
+    fn pthread_rwlock_unlock(
+        &mut self,
+        rwlock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = rwlock_get_or_create_id(this, rwlock_op)?;
+        let active_thread = this.get_active_thread();
+
+        #[allow(clippy::if_same_then_else)]
+        if this.rwlock_reader_unlock(id, active_thread) {
+            Ok(0)
+        } else if this.rwlock_writer_unlock(id, active_thread) {
+            Ok(0)
+        } else {
+            throw_ub_format!("unlocked an rwlock that was not locked by the active thread");
+        }
+    }
+
+    fn pthread_rwlock_destroy(
+        &mut self,
+        rwlock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = rwlock_get_or_create_id(this, rwlock_op)?;
+
+        if this.rwlock_is_locked(id) {
+            throw_ub_format!("destroyed a locked rwlock");
+        }
+
+        // Destroying an uninit pthread_rwlock is UB, so check to make sure it's not uninit.
+        rwlock_get_id(this, rwlock_op)?;
+
+        // This might lead to false positives, see comment in pthread_mutexattr_destroy
+        this.write_uninit(&this.deref_operand(rwlock_op)?.into())?;
+        // FIXME: delete interpreter state associated with this rwlock.
+
+        Ok(0)
+    }
+
+    fn pthread_condattr_init(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        // The default value of the clock attribute shall refer to the system
+        // clock.
+        // https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_condattr_setclock.html
+        let default_clock_id = this.eval_libc("CLOCK_REALTIME")?;
+        condattr_set_clock_id(this, attr_op, default_clock_id)?;
+
+        Ok(0)
+    }
+
+    fn pthread_condattr_setclock(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+        clock_id_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let clock_id = this.read_scalar(clock_id_op)?;
+        if clock_id == this.eval_libc("CLOCK_REALTIME")?
+            || clock_id == this.eval_libc("CLOCK_MONOTONIC")?
+        {
+            condattr_set_clock_id(this, attr_op, clock_id)?;
+        } else {
+            let einval = this.eval_libc_i32("EINVAL")?;
+            return Ok(Scalar::from_i32(einval));
+        }
+
+        Ok(Scalar::from_i32(0))
+    }
+
+    fn pthread_condattr_getclock(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+        clk_id_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let clock_id = condattr_get_clock_id(this, attr_op)?;
+        this.write_scalar(clock_id, &this.deref_operand(clk_id_op)?.into())?;
+
+        Ok(Scalar::from_i32(0))
+    }
+
+    fn pthread_condattr_destroy(
+        &mut self,
+        attr_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        // Destroying an uninit pthread_condattr is UB, so check to make sure it's not uninit.
+        condattr_get_clock_id(this, attr_op)?;
+
+        // This might lead to false positives, see comment in pthread_mutexattr_destroy
+        this.write_uninit(&this.deref_operand(attr_op)?.into())?;
+
+        Ok(0)
+    }
+
+    fn pthread_cond_init(
+        &mut self,
+        cond_op: &OpTy<'tcx, Provenance>,
+        attr_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let attr = this.read_pointer(attr_op)?;
+        let clock_id = if this.ptr_is_null(attr)? {
+            this.eval_libc("CLOCK_REALTIME")?
+        } else {
+            condattr_get_clock_id(this, attr_op)?
+        };
+
+        // Write 0 to use the same code path as the static initializers.
+        cond_set_id(this, cond_op, Scalar::from_i32(0))?;
+
+        cond_set_clock_id(this, cond_op, clock_id)?;
+
+        Ok(0)
+    }
+
+    fn pthread_cond_signal(&mut self, cond_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        let id = cond_get_or_create_id(this, cond_op)?;
+        if let Some((thread, mutex)) = this.condvar_signal(id) {
+            post_cond_signal(this, thread, mutex)?;
+        }
+
+        Ok(0)
+    }
+
+    fn pthread_cond_broadcast(
+        &mut self,
+        cond_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+        let id = cond_get_or_create_id(this, cond_op)?;
+
+        while let Some((thread, mutex)) = this.condvar_signal(id) {
+            post_cond_signal(this, thread, mutex)?;
+        }
+
+        Ok(0)
+    }
+
+    fn pthread_cond_wait(
+        &mut self,
+        cond_op: &OpTy<'tcx, Provenance>,
+        mutex_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = cond_get_or_create_id(this, cond_op)?;
+        let mutex_id = mutex_get_or_create_id(this, mutex_op)?;
+        let active_thread = this.get_active_thread();
+
+        release_cond_mutex_and_block(this, active_thread, mutex_id)?;
+        this.condvar_wait(id, active_thread, mutex_id);
+
+        Ok(0)
+    }
+
+    fn pthread_cond_timedwait(
+        &mut self,
+        cond_op: &OpTy<'tcx, Provenance>,
+        mutex_op: &OpTy<'tcx, Provenance>,
+        abstime_op: &OpTy<'tcx, Provenance>,
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        this.check_no_isolation("`pthread_cond_timedwait`")?;
+
+        let id = cond_get_or_create_id(this, cond_op)?;
+        let mutex_id = mutex_get_or_create_id(this, mutex_op)?;
+        let active_thread = this.get_active_thread();
+
+        // Extract the timeout.
+        let clock_id = cond_get_clock_id(this, cond_op)?.to_i32()?;
+        let duration = match this.read_timespec(&this.deref_operand(abstime_op)?)? {
+            Some(duration) => duration,
+            None => {
+                let einval = this.eval_libc("EINVAL")?;
+                this.write_scalar(einval, dest)?;
+                return Ok(());
+            }
+        };
+
+        let timeout_time = if clock_id == this.eval_libc_i32("CLOCK_REALTIME")? {
+            Time::RealTime(SystemTime::UNIX_EPOCH.checked_add(duration).unwrap())
+        } else if clock_id == this.eval_libc_i32("CLOCK_MONOTONIC")? {
+            Time::Monotonic(this.machine.clock.anchor().checked_add(duration).unwrap())
+        } else {
+            throw_unsup_format!("unsupported clock id: {}", clock_id);
+        };
+
+        release_cond_mutex_and_block(this, active_thread, mutex_id)?;
+        this.condvar_wait(id, active_thread, mutex_id);
+
+        // We return success for now and override it in the timeout callback.
+        this.write_scalar(Scalar::from_i32(0), dest)?;
+
+        // Register the timeout callback.
+        let dest = dest.clone();
+        this.register_timeout_callback(
+            active_thread,
+            timeout_time,
+            Box::new(move |ecx| {
+                // We are not waiting for the condvar any more, wait for the
+                // mutex instead.
+                reacquire_cond_mutex(ecx, active_thread, mutex_id)?;
+
+                // Remove the thread from the conditional variable.
+                ecx.condvar_remove_waiter(id, active_thread);
+
+                // Set the return value: we timed out.
+                let etimedout = ecx.eval_libc("ETIMEDOUT")?;
+                ecx.write_scalar(etimedout, &dest)?;
+
+                Ok(())
+            }),
+        );
+
+        Ok(())
+    }
+
+    fn pthread_cond_destroy(
+        &mut self,
+        cond_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let id = cond_get_or_create_id(this, cond_op)?;
+        if this.condvar_is_awaited(id) {
+            throw_ub_format!("destroying an awaited conditional variable");
+        }
+
+        // Destroying an uninit pthread_cond is UB, so check to make sure it's not uninit.
+        cond_get_id(this, cond_op)?;
+        cond_get_clock_id(this, cond_op)?;
+
+        // This might lead to false positives, see comment in pthread_mutexattr_destroy
+        this.write_uninit(&this.deref_operand(cond_op)?.into())?;
+        // FIXME: delete interpreter state associated with this condvar.
+
+        Ok(0)
+    }
+}
+
+fn layout_of_maybe_uninit<'tcx>(tcx: TyCtxtAt<'tcx>, param: Ty<'tcx>) -> TyAndLayout<'tcx> {
+    let def_id = tcx.require_lang_item(LangItem::MaybeUninit, None);
+    let ty = tcx.bound_type_of(def_id).subst(*tcx, &[param.into()]);
+
+    let param_env = tcx.param_env(def_id);
+    tcx.layout_of(param_env.and(ty)).unwrap()
+}
diff --git a/src/tools/miri/src/shims/unix/thread.rs b/src/tools/miri/src/shims/unix/thread.rs
new file mode 100644
index 000000000000..59474d8d10ad
--- /dev/null
+++ b/src/tools/miri/src/shims/unix/thread.rs
@@ -0,0 +1,93 @@
+use crate::*;
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_target::spec::abi::Abi;
+
+impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn pthread_create(
+        &mut self,
+        thread: &OpTy<'tcx, Provenance>,
+        _attr: &OpTy<'tcx, Provenance>,
+        start_routine: &OpTy<'tcx, Provenance>,
+        arg: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let thread_info_place = this.deref_operand(thread)?;
+
+        let start_routine = this.read_pointer(start_routine)?;
+
+        let func_arg = this.read_immediate(arg)?;
+
+        this.start_thread(
+            Some(thread_info_place),
+            start_routine,
+            Abi::C { unwind: false },
+            func_arg,
+            this.layout_of(this.tcx.types.usize)?,
+        )?;
+
+        Ok(0)
+    }
+
+    fn pthread_join(
+        &mut self,
+        thread: &OpTy<'tcx, Provenance>,
+        retval: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        if !this.ptr_is_null(this.read_pointer(retval)?)? {
+            // FIXME: implement reading the thread function's return place.
+            throw_unsup_format!("Miri supports pthread_join only with retval==NULL");
+        }
+
+        let thread_id = this.read_scalar(thread)?.to_machine_usize(this)?;
+        this.join_thread_exclusive(thread_id.try_into().expect("thread ID should fit in u32"))?;
+
+        Ok(0)
+    }
+
+    fn pthread_detach(&mut self, thread: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        let thread_id = this.read_scalar(thread)?.to_machine_usize(this)?;
+        this.detach_thread(
+            thread_id.try_into().expect("thread ID should fit in u32"),
+            /*allow_terminated_joined*/ false,
+        )?;
+
+        Ok(0)
+    }
+
+    fn pthread_self(&mut self) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let thread_id = this.get_active_thread();
+        Ok(Scalar::from_machine_usize(thread_id.into(), this))
+    }
+
+    fn pthread_setname_np(
+        &mut self,
+        thread: Scalar<Provenance>,
+        name: Scalar<Provenance>,
+    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+        let this = self.eval_context_mut();
+
+        let thread = ThreadId::try_from(thread.to_machine_usize(this)?).unwrap();
+        let name = name.to_pointer(this)?;
+
+        let name = this.read_c_str(name)?.to_owned();
+        this.set_thread_name(thread, name);
+
+        Ok(Scalar::from_u32(0))
+    }
+
+    fn sched_yield(&mut self) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.yield_active_thread();
+
+        Ok(0)
+    }
+}
diff --git a/src/tools/miri/src/shims/windows/dlsym.rs b/src/tools/miri/src/shims/windows/dlsym.rs
new file mode 100644
index 000000000000..41b9473f81fe
--- /dev/null
+++ b/src/tools/miri/src/shims/windows/dlsym.rs
@@ -0,0 +1,136 @@
+use rustc_middle::mir;
+use rustc_target::abi::Size;
+use rustc_target::spec::abi::Abi;
+
+use log::trace;
+
+use crate::helpers::check_arg_count;
+use crate::shims::windows::handle::{EvalContextExt as _, Handle, PseudoHandle};
+use crate::*;
+
+#[derive(Debug, Copy, Clone)]
+pub enum Dlsym {
+    NtWriteFile,
+    SetThreadDescription,
+}
+
+impl Dlsym {
+    // Returns an error for unsupported symbols, and None if this symbol
+    // should become a NULL pointer (pretend it does not exist).
+    pub fn from_str<'tcx>(name: &str) -> InterpResult<'tcx, Option<Dlsym>> {
+        Ok(match name {
+            "GetSystemTimePreciseAsFileTime" => None,
+            "NtWriteFile" => Some(Dlsym::NtWriteFile),
+            "SetThreadDescription" => Some(Dlsym::SetThreadDescription),
+            _ => throw_unsup_format!("unsupported Windows dlsym: {}", name),
+        })
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn call_dlsym(
+        &mut self,
+        dlsym: Dlsym,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+        ret: Option<mir::BasicBlock>,
+    ) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let ret = ret.expect("we don't support any diverging dlsym");
+        assert!(this.tcx.sess.target.os == "windows");
+
+        this.check_abi(abi, Abi::System { unwind: false })?;
+
+        match dlsym {
+            Dlsym::NtWriteFile => {
+                if !this.frame_in_std() {
+                    throw_unsup_format!(
+                        "`NtWriteFile` support is crude and just enough for stdout to work"
+                    );
+                }
+
+                let [
+                    handle,
+                    _event,
+                    _apc_routine,
+                    _apc_context,
+                    io_status_block,
+                    buf,
+                    n,
+                    byte_offset,
+                    _key,
+                ] = check_arg_count(args)?;
+                let handle = this.read_scalar(handle)?.to_machine_isize(this)?;
+                let buf = this.read_pointer(buf)?;
+                let n = this.read_scalar(n)?.to_u32()?;
+                let byte_offset = this.read_scalar(byte_offset)?.to_machine_usize(this)?; // is actually a pointer
+                let io_status_block = this.deref_operand(io_status_block)?;
+
+                if byte_offset != 0 {
+                    throw_unsup_format!(
+                        "`NtWriteFile` `ByteOffset` paremeter is non-null, which is unsupported"
+                    );
+                }
+
+                let written = if handle == -11 || handle == -12 {
+                    // stdout/stderr
+                    use std::io::{self, Write};
+
+                    let buf_cont =
+                        this.read_bytes_ptr_strip_provenance(buf, Size::from_bytes(u64::from(n)))?;
+                    let res = if this.machine.mute_stdout_stderr {
+                        Ok(buf_cont.len())
+                    } else if handle == -11 {
+                        io::stdout().write(buf_cont)
+                    } else {
+                        io::stderr().write(buf_cont)
+                    };
+                    // We write at most `n` bytes, which is a `u32`, so we cannot have written more than that.
+                    res.ok().map(|n| u32::try_from(n).unwrap())
+                } else {
+                    throw_unsup_format!(
+                        "on Windows, writing to anything except stdout/stderr is not supported"
+                    )
+                };
+                // We have to put the result into io_status_block.
+                if let Some(n) = written {
+                    let io_status_information =
+                        this.mplace_field_named(&io_status_block, "Information")?;
+                    this.write_scalar(
+                        Scalar::from_machine_usize(n.into(), this),
+                        &io_status_information.into(),
+                    )?;
+                }
+                // Return whether this was a success. >= 0 is success.
+                // For the error code we arbitrarily pick 0xC0000185, STATUS_IO_DEVICE_ERROR.
+                this.write_scalar(
+                    Scalar::from_u32(if written.is_some() { 0 } else { 0xC0000185u32 }),
+                    dest,
+                )?;
+            }
+            Dlsym::SetThreadDescription => {
+                let [handle, name] = check_arg_count(args)?;
+
+                let handle = this.read_scalar(handle)?;
+
+                let name = this.read_wide_str(this.read_pointer(name)?)?;
+
+                let thread = match Handle::from_scalar(handle, this)? {
+                    Some(Handle::Thread(thread)) => thread,
+                    Some(Handle::Pseudo(PseudoHandle::CurrentThread)) => this.get_active_thread(),
+                    _ => this.invalid_handle("SetThreadDescription")?,
+                };
+
+                this.set_thread_name_wide(thread, &name);
+
+                this.write_null(dest)?;
+            }
+        }
+
+        trace!("{:?}", this.dump_place(**dest));
+        this.go_to_block(ret);
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/windows/foreign_items.rs b/src/tools/miri/src/shims/windows/foreign_items.rs
new file mode 100644
index 000000000000..53ab97b255e5
--- /dev/null
+++ b/src/tools/miri/src/shims/windows/foreign_items.rs
@@ -0,0 +1,442 @@
+use std::iter;
+
+use rustc_span::Symbol;
+use rustc_target::abi::Size;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::foreign_items::EmulateByNameResult;
+use shims::windows::handle::{EvalContextExt as _, Handle, PseudoHandle};
+use shims::windows::sync::EvalContextExt as _;
+use shims::windows::thread::EvalContextExt as _;
+
+use smallvec::SmallVec;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn emulate_foreign_item_by_name(
+        &mut self,
+        link_name: Symbol,
+        abi: Abi,
+        args: &[OpTy<'tcx, Provenance>],
+        dest: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
+        let this = self.eval_context_mut();
+
+        // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.
+
+        // Windows API stubs.
+        // HANDLE = isize
+        // NTSTATUS = LONH = i32
+        // DWORD = ULONG = u32
+        // BOOL = i32
+        // BOOLEAN = u8
+        match link_name.as_str() {
+            // Environment related shims
+            "GetEnvironmentVariableW" => {
+                let [name, buf, size] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.GetEnvironmentVariableW(name, buf, size)?;
+                this.write_scalar(Scalar::from_u32(result), dest)?;
+            }
+            "SetEnvironmentVariableW" => {
+                let [name, value] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.SetEnvironmentVariableW(name, value)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "GetEnvironmentStringsW" => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.GetEnvironmentStringsW()?;
+                this.write_pointer(result, dest)?;
+            }
+            "FreeEnvironmentStringsW" => {
+                let [env_block] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.FreeEnvironmentStringsW(env_block)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "GetCurrentDirectoryW" => {
+                let [size, buf] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.GetCurrentDirectoryW(size, buf)?;
+                this.write_scalar(Scalar::from_u32(result), dest)?;
+            }
+            "SetCurrentDirectoryW" => {
+                let [path] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.SetCurrentDirectoryW(path)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+
+            // Allocation
+            "HeapAlloc" => {
+                let [handle, flags, size] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.read_scalar(handle)?.to_machine_isize(this)?;
+                let flags = this.read_scalar(flags)?.to_u32()?;
+                let size = this.read_scalar(size)?.to_machine_usize(this)?;
+                let zero_init = (flags & 0x00000008) != 0; // HEAP_ZERO_MEMORY
+                let res = this.malloc(size, zero_init, MiriMemoryKind::WinHeap)?;
+                this.write_pointer(res, dest)?;
+            }
+            "HeapFree" => {
+                let [handle, flags, ptr] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.read_scalar(handle)?.to_machine_isize(this)?;
+                this.read_scalar(flags)?.to_u32()?;
+                let ptr = this.read_pointer(ptr)?;
+                this.free(ptr, MiriMemoryKind::WinHeap)?;
+                this.write_scalar(Scalar::from_i32(1), dest)?;
+            }
+            "HeapReAlloc" => {
+                let [handle, flags, ptr, size] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.read_scalar(handle)?.to_machine_isize(this)?;
+                this.read_scalar(flags)?.to_u32()?;
+                let ptr = this.read_pointer(ptr)?;
+                let size = this.read_scalar(size)?.to_machine_usize(this)?;
+                let res = this.realloc(ptr, size, MiriMemoryKind::WinHeap)?;
+                this.write_pointer(res, dest)?;
+            }
+
+            // errno
+            "SetLastError" => {
+                let [error] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let error = this.read_scalar(error)?;
+                this.set_last_error(error)?;
+            }
+            "GetLastError" => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let last_error = this.get_last_error()?;
+                this.write_scalar(last_error, dest)?;
+            }
+
+            // Querying system information
+            "GetSystemInfo" => {
+                // Also called from `page_size` crate.
+                let [system_info] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let system_info = this.deref_operand(system_info)?;
+                // Initialize with `0`.
+                this.write_bytes_ptr(
+                    system_info.ptr,
+                    iter::repeat(0u8).take(system_info.layout.size.bytes_usize()),
+                )?;
+                // Set selected fields.
+                let word_layout = this.machine.layouts.u16;
+                let dword_layout = this.machine.layouts.u32;
+                let usize_layout = this.machine.layouts.usize;
+
+                // Using `mplace_field` is error-prone, see: https://github.com/rust-lang/miri/issues/2136.
+                // Pointer fields have different sizes on different targets.
+                // To avoid all these issue we calculate the offsets ourselves.
+                let field_sizes = [
+                    word_layout.size,  // 0,  wProcessorArchitecture      : WORD
+                    word_layout.size,  // 1,  wReserved                   : WORD
+                    dword_layout.size, // 2,  dwPageSize                  : DWORD
+                    usize_layout.size, // 3,  lpMinimumApplicationAddress : LPVOID
+                    usize_layout.size, // 4,  lpMaximumApplicationAddress : LPVOID
+                    usize_layout.size, // 5,  dwActiveProcessorMask       : DWORD_PTR
+                    dword_layout.size, // 6,  dwNumberOfProcessors        : DWORD
+                    dword_layout.size, // 7,  dwProcessorType             : DWORD
+                    dword_layout.size, // 8,  dwAllocationGranularity     : DWORD
+                    word_layout.size,  // 9,  wProcessorLevel             : WORD
+                    word_layout.size,  // 10, wProcessorRevision          : WORD
+                ];
+                let field_offsets: SmallVec<[Size; 11]> = field_sizes
+                    .iter()
+                    .copied()
+                    .scan(Size::ZERO, |a, x| {
+                        let res = Some(*a);
+                        *a += x;
+                        res
+                    })
+                    .collect();
+
+                // Set page size.
+                let page_size = system_info.offset(field_offsets[2], dword_layout, &this.tcx)?;
+                this.write_scalar(
+                    Scalar::from_int(PAGE_SIZE, dword_layout.size),
+                    &page_size.into(),
+                )?;
+                // Set number of processors.
+                let num_cpus = system_info.offset(field_offsets[6], dword_layout, &this.tcx)?;
+                this.write_scalar(Scalar::from_int(NUM_CPUS, dword_layout.size), &num_cpus.into())?;
+            }
+
+            // Thread-local storage
+            "TlsAlloc" => {
+                // This just creates a key; Windows does not natively support TLS destructors.
+
+                // Create key and return it.
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let key = this.machine.tls.create_tls_key(None, dest.layout.size)?;
+                this.write_scalar(Scalar::from_uint(key, dest.layout.size), dest)?;
+            }
+            "TlsGetValue" => {
+                let [key] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let key = u128::from(this.read_scalar(key)?.to_u32()?);
+                let active_thread = this.get_active_thread();
+                let ptr = this.machine.tls.load_tls(key, active_thread, this)?;
+                this.write_scalar(ptr, dest)?;
+            }
+            "TlsSetValue" => {
+                let [key, new_ptr] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let key = u128::from(this.read_scalar(key)?.to_u32()?);
+                let active_thread = this.get_active_thread();
+                let new_data = this.read_scalar(new_ptr)?;
+                this.machine.tls.store_tls(key, active_thread, new_data, &*this.tcx)?;
+
+                // Return success (`1`).
+                this.write_scalar(Scalar::from_i32(1), dest)?;
+            }
+
+            // Access to command-line arguments
+            "GetCommandLineW" => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.write_pointer(
+                    this.machine.cmd_line.expect("machine must be initialized").ptr,
+                    dest,
+                )?;
+            }
+
+            // Time related shims
+            "GetSystemTimeAsFileTime" => {
+                #[allow(non_snake_case)]
+                let [LPFILETIME] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.GetSystemTimeAsFileTime(LPFILETIME)?;
+            }
+            "QueryPerformanceCounter" => {
+                #[allow(non_snake_case)]
+                let [lpPerformanceCount] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.QueryPerformanceCounter(lpPerformanceCount)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "QueryPerformanceFrequency" => {
+                #[allow(non_snake_case)]
+                let [lpFrequency] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.QueryPerformanceFrequency(lpFrequency)?;
+                this.write_scalar(Scalar::from_i32(result), dest)?;
+            }
+            "Sleep" => {
+                let [timeout] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.Sleep(timeout)?;
+            }
+
+            // Synchronization primitives
+            "AcquireSRWLockExclusive" => {
+                let [ptr] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.AcquireSRWLockExclusive(ptr)?;
+            }
+            "ReleaseSRWLockExclusive" => {
+                let [ptr] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.ReleaseSRWLockExclusive(ptr)?;
+            }
+            "TryAcquireSRWLockExclusive" => {
+                let [ptr] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let ret = this.TryAcquireSRWLockExclusive(ptr)?;
+                this.write_scalar(Scalar::from_u8(ret), dest)?;
+            }
+            "AcquireSRWLockShared" => {
+                let [ptr] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.AcquireSRWLockShared(ptr)?;
+            }
+            "ReleaseSRWLockShared" => {
+                let [ptr] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.ReleaseSRWLockShared(ptr)?;
+            }
+            "TryAcquireSRWLockShared" => {
+                let [ptr] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let ret = this.TryAcquireSRWLockShared(ptr)?;
+                this.write_scalar(Scalar::from_u8(ret), dest)?;
+            }
+
+            // Dynamic symbol loading
+            "GetProcAddress" => {
+                #[allow(non_snake_case)]
+                let [hModule, lpProcName] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.read_scalar(hModule)?.to_machine_isize(this)?;
+                let name = this.read_c_str(this.read_pointer(lpProcName)?)?;
+                if let Some(dlsym) = Dlsym::from_str(name, &this.tcx.sess.target.os)? {
+                    let ptr = this.create_fn_alloc_ptr(FnVal::Other(dlsym));
+                    this.write_pointer(ptr, dest)?;
+                } else {
+                    this.write_null(dest)?;
+                }
+            }
+
+            // Miscellaneous
+            "SystemFunction036" => {
+                // This is really 'RtlGenRandom'.
+                let [ptr, len] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let ptr = this.read_pointer(ptr)?;
+                let len = this.read_scalar(len)?.to_u32()?;
+                this.gen_random(ptr, len.into())?;
+                this.write_scalar(Scalar::from_bool(true), dest)?;
+            }
+            "BCryptGenRandom" => {
+                let [algorithm, ptr, len, flags] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let algorithm = this.read_scalar(algorithm)?;
+                let algorithm = algorithm.to_machine_usize(this)?;
+                let ptr = this.read_pointer(ptr)?;
+                let len = this.read_scalar(len)?.to_u32()?;
+                let flags = this.read_scalar(flags)?.to_u32()?;
+                match flags {
+                    0 => {
+                        if algorithm != 0x81 {
+                            // BCRYPT_RNG_ALG_HANDLE
+                            throw_unsup_format!(
+                                "BCryptGenRandom algorithm must be BCRYPT_RNG_ALG_HANDLE when the flag is 0"
+                            );
+                        }
+                    }
+                    2 => {
+                        // BCRYPT_USE_SYSTEM_PREFERRED_RNG
+                        if algorithm != 0 {
+                            throw_unsup_format!(
+                                "BCryptGenRandom algorithm must be NULL when the flag is BCRYPT_USE_SYSTEM_PREFERRED_RNG"
+                            );
+                        }
+                    }
+                    _ => {
+                        throw_unsup_format!(
+                            "BCryptGenRandom is only supported with BCRYPT_USE_SYSTEM_PREFERRED_RNG or BCRYPT_RNG_ALG_HANDLE"
+                        );
+                    }
+                }
+                this.gen_random(ptr, len.into())?;
+                this.write_null(dest)?; // STATUS_SUCCESS
+            }
+            "GetConsoleScreenBufferInfo" => {
+                // `term` needs this, so we fake it.
+                let [console, buffer_info] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.read_scalar(console)?.to_machine_isize(this)?;
+                this.deref_operand(buffer_info)?;
+                // Indicate an error.
+                // FIXME: we should set last_error, but to what?
+                this.write_null(dest)?;
+            }
+            "GetConsoleMode" => {
+                // Windows "isatty" (in libtest) needs this, so we fake it.
+                let [console, mode] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                this.read_scalar(console)?.to_machine_isize(this)?;
+                this.deref_operand(mode)?;
+                // Indicate an error.
+                // FIXME: we should set last_error, but to what?
+                this.write_null(dest)?;
+            }
+            "GetStdHandle" => {
+                let [which] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let which = this.read_scalar(which)?.to_i32()?;
+                // We just make this the identity function, so we know later in `NtWriteFile` which
+                // one it is. This is very fake, but libtest needs it so we cannot make it a
+                // std-only shim.
+                // FIXME: this should return real HANDLEs when io support is added
+                this.write_scalar(Scalar::from_machine_isize(which.into(), this), dest)?;
+            }
+            "CloseHandle" => {
+                let [handle] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.CloseHandle(handle)?;
+
+                this.write_scalar(Scalar::from_u32(1), dest)?;
+            }
+
+            // Threading
+            "CreateThread" => {
+                let [security, stacksize, start, arg, flags, thread] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                let thread_id =
+                    this.CreateThread(security, stacksize, start, arg, flags, thread)?;
+
+                this.write_scalar(Handle::Thread(thread_id).to_scalar(this), dest)?;
+            }
+            "WaitForSingleObject" => {
+                let [handle, timeout] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                let ret = this.WaitForSingleObject(handle, timeout)?;
+                this.write_scalar(Scalar::from_u32(ret), dest)?;
+            }
+            "GetCurrentThread" => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.write_scalar(
+                    Handle::Pseudo(PseudoHandle::CurrentThread).to_scalar(this),
+                    dest,
+                )?;
+            }
+
+            // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
+            // These shims are enabled only when the caller is in the standard library.
+            "GetProcessHeap" if this.frame_in_std() => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                // Just fake a HANDLE
+                // It's fine to not use the Handle type here because its a stub
+                this.write_scalar(Scalar::from_machine_isize(1, this), dest)?;
+            }
+            "GetModuleHandleA" if this.frame_in_std() => {
+                #[allow(non_snake_case)]
+                let [_lpModuleName] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                // We need to return something non-null here to make `compat_fn!` work.
+                this.write_scalar(Scalar::from_machine_isize(1, this), dest)?;
+            }
+            "SetConsoleTextAttribute" if this.frame_in_std() => {
+                #[allow(non_snake_case)]
+                let [_hConsoleOutput, _wAttribute] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                // Pretend these does not exist / nothing happened, by returning zero.
+                this.write_null(dest)?;
+            }
+            "AddVectoredExceptionHandler" if this.frame_in_std() => {
+                #[allow(non_snake_case)]
+                let [_First, _Handler] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                // Any non zero value works for the stdlib. This is just used for stack overflows anyway.
+                this.write_scalar(Scalar::from_machine_usize(1, this), dest)?;
+            }
+            "SetThreadStackGuarantee" if this.frame_in_std() => {
+                #[allow(non_snake_case)]
+                let [_StackSizeInBytes] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                // Any non zero value works for the stdlib. This is just used for stack overflows anyway.
+                this.write_scalar(Scalar::from_u32(1), dest)?;
+            }
+            "GetCurrentProcessId" if this.frame_in_std() => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+                let result = this.GetCurrentProcessId()?;
+                this.write_scalar(Scalar::from_u32(result), dest)?;
+            }
+            // this is only callable from std because we know that std ignores the return value
+            "SwitchToThread" if this.frame_in_std() => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.yield_active_thread();
+
+                // FIXME: this should return a nonzero value if this call does result in switching to another thread.
+                this.write_null(dest)?;
+            }
+
+            _ => return Ok(EmulateByNameResult::NotSupported),
+        }
+
+        Ok(EmulateByNameResult::NeedsJumping)
+    }
+}
diff --git a/src/tools/miri/src/shims/windows/handle.rs b/src/tools/miri/src/shims/windows/handle.rs
new file mode 100644
index 000000000000..5b22c4bd7358
--- /dev/null
+++ b/src/tools/miri/src/shims/windows/handle.rs
@@ -0,0 +1,171 @@
+use rustc_target::abi::HasDataLayout;
+use std::mem::variant_count;
+
+use crate::*;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum PseudoHandle {
+    CurrentThread,
+}
+
+/// Miri representation of a Windows `HANDLE`
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum Handle {
+    Null,
+    Pseudo(PseudoHandle),
+    Thread(ThreadId),
+}
+
+impl PseudoHandle {
+    const CURRENT_THREAD_VALUE: u32 = 0;
+
+    fn value(self) -> u32 {
+        match self {
+            Self::CurrentThread => Self::CURRENT_THREAD_VALUE,
+        }
+    }
+
+    fn from_value(value: u32) -> Option<Self> {
+        match value {
+            Self::CURRENT_THREAD_VALUE => Some(Self::CurrentThread),
+            _ => None,
+        }
+    }
+}
+
+impl Handle {
+    const NULL_DISCRIMINANT: u32 = 0;
+    const PSEUDO_DISCRIMINANT: u32 = 1;
+    const THREAD_DISCRIMINANT: u32 = 2;
+
+    fn discriminant(self) -> u32 {
+        match self {
+            Self::Null => Self::NULL_DISCRIMINANT,
+            Self::Pseudo(_) => Self::PSEUDO_DISCRIMINANT,
+            Self::Thread(_) => Self::THREAD_DISCRIMINANT,
+        }
+    }
+
+    fn data(self) -> u32 {
+        match self {
+            Self::Null => 0,
+            Self::Pseudo(pseudo_handle) => pseudo_handle.value(),
+            Self::Thread(thread) => thread.to_u32(),
+        }
+    }
+
+    fn packed_disc_size() -> u32 {
+        // ceil(log2(x)) is how many bits it takes to store x numbers
+        let variant_count = variant_count::<Self>();
+
+        // however, std's ilog2 is floor(log2(x))
+        let floor_log2 = variant_count.ilog2();
+
+        // we need to add one for non powers of two to compensate for the difference
+        #[allow(clippy::integer_arithmetic)] // cannot overflow
+        if variant_count.is_power_of_two() { floor_log2 } else { floor_log2 + 1 }
+    }
+
+    /// Converts a handle into its machine representation.
+    ///
+    /// The upper [`Self::packed_disc_size()`] bits are used to store a discriminant corresponding to the handle variant.
+    /// The remaining bits are used for the variant's field.
+    ///
+    /// None of this layout is guaranteed to applications by Windows or Miri.
+    fn to_packed(self) -> u32 {
+        let disc_size = Self::packed_disc_size();
+        let data_size = u32::BITS.checked_sub(disc_size).unwrap();
+
+        let discriminant = self.discriminant();
+        let data = self.data();
+
+        // make sure the discriminant fits into `disc_size` bits
+        assert!(discriminant < 2u32.pow(disc_size));
+
+        // make sure the data fits into `data_size` bits
+        assert!(data < 2u32.pow(data_size));
+
+        // packs the data into the lower `data_size` bits
+        // and packs the discriminant right above the data
+        #[allow(clippy::integer_arithmetic)] // cannot overflow
+        return discriminant << data_size | data;
+    }
+
+    fn new(discriminant: u32, data: u32) -> Option<Self> {
+        match discriminant {
+            Self::NULL_DISCRIMINANT if data == 0 => Some(Self::Null),
+            Self::PSEUDO_DISCRIMINANT => Some(Self::Pseudo(PseudoHandle::from_value(data)?)),
+            Self::THREAD_DISCRIMINANT => Some(Self::Thread(data.into())),
+            _ => None,
+        }
+    }
+
+    /// see docs for `to_packed`
+    fn from_packed(handle: u32) -> Option<Self> {
+        let disc_size = Self::packed_disc_size();
+        let data_size = u32::BITS.checked_sub(disc_size).unwrap();
+
+        // the lower `data_size` bits of this mask are 1
+        #[allow(clippy::integer_arithmetic)] // cannot overflow
+        let data_mask = 2u32.pow(data_size) - 1;
+
+        // the discriminant is stored right above the lower `data_size` bits
+        #[allow(clippy::integer_arithmetic)] // cannot overflow
+        let discriminant = handle >> data_size;
+
+        // the data is stored in the lower `data_size` bits
+        let data = handle & data_mask;
+
+        Self::new(discriminant, data)
+    }
+
+    pub fn to_scalar(self, cx: &impl HasDataLayout) -> Scalar<Provenance> {
+        // 64-bit handles are sign extended 32-bit handles
+        // see https://docs.microsoft.com/en-us/windows/win32/winprog64/interprocess-communication
+        #[allow(clippy::cast_possible_wrap)] // we want it to wrap
+        let signed_handle = self.to_packed() as i32;
+        Scalar::from_machine_isize(signed_handle.into(), cx)
+    }
+
+    pub fn from_scalar<'tcx>(
+        handle: Scalar<Provenance>,
+        cx: &impl HasDataLayout,
+    ) -> InterpResult<'tcx, Option<Self>> {
+        let sign_extended_handle = handle.to_machine_isize(cx)?;
+
+        #[allow(clippy::cast_sign_loss)] // we want to lose the sign
+        let handle = if let Ok(signed_handle) = i32::try_from(sign_extended_handle) {
+            signed_handle as u32
+        } else {
+            // if a handle doesn't fit in an i32, it isn't valid.
+            return Ok(None);
+        };
+
+        Ok(Self::from_packed(handle))
+    }
+}
+
+impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+
+#[allow(non_snake_case)]
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn invalid_handle(&mut self, function_name: &str) -> InterpResult<'tcx, !> {
+        throw_machine_stop!(TerminationInfo::Abort(format!(
+            "invalid handle passed to `{function_name}`"
+        )))
+    }
+
+    fn CloseHandle(&mut self, handle_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        let handle = this.read_scalar(handle_op)?;
+
+        match Handle::from_scalar(handle, this)? {
+            Some(Handle::Thread(thread)) =>
+                this.detach_thread(thread, /*allow_terminated_joined*/ true)?,
+            _ => this.invalid_handle("CloseHandle")?,
+        }
+
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/windows/mod.rs b/src/tools/miri/src/shims/windows/mod.rs
new file mode 100644
index 000000000000..40fe71b2dbd0
--- /dev/null
+++ b/src/tools/miri/src/shims/windows/mod.rs
@@ -0,0 +1,6 @@
+pub mod dlsym;
+pub mod foreign_items;
+
+mod handle;
+mod sync;
+mod thread;
diff --git a/src/tools/miri/src/shims/windows/sync.rs b/src/tools/miri/src/shims/windows/sync.rs
new file mode 100644
index 000000000000..dc1052a824de
--- /dev/null
+++ b/src/tools/miri/src/shims/windows/sync.rs
@@ -0,0 +1,138 @@
+use crate::*;
+
+// Locks are pointer-sized pieces of data, initialized to 0.
+// We use the first 4 bytes to store the RwLockId.
+
+fn srwlock_get_or_create_id<'mir, 'tcx: 'mir>(
+    ecx: &mut MiriInterpCx<'mir, 'tcx>,
+    lock_op: &OpTy<'tcx, Provenance>,
+) -> InterpResult<'tcx, RwLockId> {
+    let value_place = ecx.deref_operand_and_offset(lock_op, 0, ecx.machine.layouts.u32)?;
+
+    ecx.rwlock_get_or_create(|ecx, next_id| {
+        let (old, success) = ecx
+            .atomic_compare_exchange_scalar(
+                &value_place,
+                &ImmTy::from_uint(0u32, ecx.machine.layouts.u32),
+                next_id.to_u32_scalar(),
+                AtomicRwOrd::Relaxed,
+                AtomicReadOrd::Relaxed,
+                false,
+            )?
+            .to_scalar_pair();
+
+        Ok(if success.to_bool().expect("compare_exchange's second return value is a bool") {
+            // Caller of the closure needs to allocate next_id
+            None
+        } else {
+            Some(RwLockId::from_u32(old.to_u32().expect("layout is u32")))
+        })
+    })
+}
+
+impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    #[allow(non_snake_case)]
+    fn AcquireSRWLockExclusive(&mut self, lock_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let id = srwlock_get_or_create_id(this, lock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_locked(id) {
+            // Note: this will deadlock if the lock is already locked by this
+            // thread in any way.
+            //
+            // FIXME: Detect and report the deadlock proactively. (We currently
+            // report the deadlock only when no thread can continue execution,
+            // but we could detect that this lock is already locked and report
+            // an error.)
+            this.rwlock_enqueue_and_block_writer(id, active_thread);
+        } else {
+            this.rwlock_writer_lock(id, active_thread);
+        }
+
+        Ok(())
+    }
+
+    #[allow(non_snake_case)]
+    fn TryAcquireSRWLockExclusive(
+        &mut self,
+        lock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, u8> {
+        let this = self.eval_context_mut();
+        let id = srwlock_get_or_create_id(this, lock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_locked(id) {
+            // Lock is already held.
+            Ok(0)
+        } else {
+            this.rwlock_writer_lock(id, active_thread);
+            Ok(1)
+        }
+    }
+
+    #[allow(non_snake_case)]
+    fn ReleaseSRWLockExclusive(&mut self, lock_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let id = srwlock_get_or_create_id(this, lock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if !this.rwlock_writer_unlock(id, active_thread) {
+            // The docs do not say anything about this case, but it seems better to not allow it.
+            throw_ub_format!(
+                "calling ReleaseSRWLockExclusive on an SRWLock that is not exclusively locked by the current thread"
+            );
+        }
+
+        Ok(())
+    }
+
+    #[allow(non_snake_case)]
+    fn AcquireSRWLockShared(&mut self, lock_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let id = srwlock_get_or_create_id(this, lock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_write_locked(id) {
+            this.rwlock_enqueue_and_block_reader(id, active_thread);
+        } else {
+            this.rwlock_reader_lock(id, active_thread);
+        }
+
+        Ok(())
+    }
+
+    #[allow(non_snake_case)]
+    fn TryAcquireSRWLockShared(
+        &mut self,
+        lock_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, u8> {
+        let this = self.eval_context_mut();
+        let id = srwlock_get_or_create_id(this, lock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if this.rwlock_is_write_locked(id) {
+            Ok(0)
+        } else {
+            this.rwlock_reader_lock(id, active_thread);
+            Ok(1)
+        }
+    }
+
+    #[allow(non_snake_case)]
+    fn ReleaseSRWLockShared(&mut self, lock_op: &OpTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let id = srwlock_get_or_create_id(this, lock_op)?;
+        let active_thread = this.get_active_thread();
+
+        if !this.rwlock_reader_unlock(id, active_thread) {
+            // The docs do not say anything about this case, but it seems better to not allow it.
+            throw_ub_format!(
+                "calling ReleaseSRWLockShared on an SRWLock that is not locked by the current thread"
+            );
+        }
+
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/shims/windows/thread.rs b/src/tools/miri/src/shims/windows/thread.rs
new file mode 100644
index 000000000000..5ed0cb92f9e3
--- /dev/null
+++ b/src/tools/miri/src/shims/windows/thread.rs
@@ -0,0 +1,84 @@
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_target::spec::abi::Abi;
+
+use crate::*;
+use shims::windows::handle::{EvalContextExt as _, Handle, PseudoHandle};
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+
+#[allow(non_snake_case)]
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn CreateThread(
+        &mut self,
+        security_op: &OpTy<'tcx, Provenance>,
+        stacksize_op: &OpTy<'tcx, Provenance>,
+        start_op: &OpTy<'tcx, Provenance>,
+        arg_op: &OpTy<'tcx, Provenance>,
+        flags_op: &OpTy<'tcx, Provenance>,
+        thread_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, ThreadId> {
+        let this = self.eval_context_mut();
+
+        let security = this.read_pointer(security_op)?;
+        // stacksize is ignored, but still needs to be a valid usize
+        this.read_scalar(stacksize_op)?.to_machine_usize(this)?;
+        let start_routine = this.read_pointer(start_op)?;
+        let func_arg = this.read_immediate(arg_op)?;
+        let flags = this.read_scalar(flags_op)?.to_u32()?;
+
+        let thread = if this.ptr_is_null(this.read_pointer(thread_op)?)? {
+            None
+        } else {
+            let thread_info_place = this.deref_operand(thread_op)?;
+            Some(thread_info_place)
+        };
+
+        let stack_size_param_is_a_reservation =
+            this.eval_windows("c", "STACK_SIZE_PARAM_IS_A_RESERVATION")?.to_u32()?;
+
+        // We ignore the stack size, so we also ignore the
+        // `STACK_SIZE_PARAM_IS_A_RESERVATION` flag.
+        if flags != 0 && flags != stack_size_param_is_a_reservation {
+            throw_unsup_format!("unsupported `dwCreationFlags` {} in `CreateThread`", flags)
+        }
+
+        if !this.ptr_is_null(security)? {
+            throw_unsup_format!("non-null `lpThreadAttributes` in `CreateThread`")
+        }
+
+        this.start_thread(
+            thread,
+            start_routine,
+            Abi::System { unwind: false },
+            func_arg,
+            this.layout_of(this.tcx.types.u32)?,
+        )
+    }
+
+    fn WaitForSingleObject(
+        &mut self,
+        handle_op: &OpTy<'tcx, Provenance>,
+        timeout_op: &OpTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, u32> {
+        let this = self.eval_context_mut();
+
+        let handle = this.read_scalar(handle_op)?;
+        let timeout = this.read_scalar(timeout_op)?.to_u32()?;
+
+        let thread = match Handle::from_scalar(handle, this)? {
+            Some(Handle::Thread(thread)) => thread,
+            // Unlike on posix, the outcome of joining the current thread is not documented.
+            // On current Windows, it just deadlocks.
+            Some(Handle::Pseudo(PseudoHandle::CurrentThread)) => this.get_active_thread(),
+            _ => this.invalid_handle("WaitForSingleObject")?,
+        };
+
+        if timeout != this.eval_windows("c", "INFINITE")?.to_u32()? {
+            throw_unsup_format!("`WaitForSingleObject` with non-infinite timeout");
+        }
+
+        this.join_thread(thread)?;
+
+        Ok(0)
+    }
+}
diff --git a/src/tools/miri/src/stacked_borrows/diagnostics.rs b/src/tools/miri/src/stacked_borrows/diagnostics.rs
new file mode 100644
index 000000000000..0d76ed4e3087
--- /dev/null
+++ b/src/tools/miri/src/stacked_borrows/diagnostics.rs
@@ -0,0 +1,509 @@
+use smallvec::SmallVec;
+use std::fmt;
+
+use rustc_middle::mir::interpret::{alloc_range, AllocId, AllocRange};
+use rustc_span::{Span, SpanData};
+use rustc_target::abi::Size;
+
+use crate::helpers::CurrentSpan;
+use crate::stacked_borrows::{err_sb_ub, AccessKind, GlobalStateInner, Permission};
+use crate::*;
+
+use rustc_middle::mir::interpret::InterpError;
+
+#[derive(Clone, Debug)]
+pub struct AllocHistory {
+    id: AllocId,
+    base: (Item, Span),
+    creations: smallvec::SmallVec<[Creation; 1]>,
+    invalidations: smallvec::SmallVec<[Invalidation; 1]>,
+    protectors: smallvec::SmallVec<[Protection; 1]>,
+}
+
+#[derive(Clone, Debug)]
+struct Creation {
+    retag: RetagOp,
+    span: Span,
+}
+
+impl Creation {
+    fn generate_diagnostic(&self) -> (String, SpanData) {
+        let tag = self.retag.new_tag;
+        if let Some(perm) = self.retag.permission {
+            (
+                format!(
+                    "{tag:?} was created by a {:?} retag at offsets {:?}",
+                    perm, self.retag.range,
+                ),
+                self.span.data(),
+            )
+        } else {
+            assert!(self.retag.range.size == Size::ZERO);
+            (
+                format!(
+                    "{tag:?} would have been created here, but this is a zero-size retag ({:?}) so the tag in question does not exist anywhere",
+                    self.retag.range,
+                ),
+                self.span.data(),
+            )
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Invalidation {
+    tag: SbTag,
+    range: AllocRange,
+    span: Span,
+    cause: InvalidationCause,
+}
+
+#[derive(Clone, Debug)]
+enum InvalidationCause {
+    Access(AccessKind),
+    Retag(Permission, RetagCause),
+}
+
+impl Invalidation {
+    fn generate_diagnostic(&self) -> (String, SpanData) {
+        (
+            format!(
+                "{:?} was later invalidated at offsets {:?} by a {}",
+                self.tag, self.range, self.cause
+            ),
+            self.span.data(),
+        )
+    }
+}
+
+impl fmt::Display for InvalidationCause {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            InvalidationCause::Access(kind) => write!(f, "{}", kind),
+            InvalidationCause::Retag(perm, kind) =>
+                if *kind == RetagCause::FnEntry {
+                    write!(f, "{:?} FnEntry retag", perm)
+                } else {
+                    write!(f, "{:?} retag", perm)
+                },
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Protection {
+    tag: SbTag,
+    span: Span,
+}
+
+#[derive(Clone)]
+pub struct TagHistory {
+    pub created: (String, SpanData),
+    pub invalidated: Option<(String, SpanData)>,
+    pub protected: Option<(String, SpanData)>,
+}
+
+pub struct DiagnosticCxBuilder<'span, 'ecx, 'mir, 'tcx> {
+    operation: Operation,
+    // 'span cannot be merged with any other lifetime since they appear invariantly, under the
+    // mutable ref.
+    current_span: &'span mut CurrentSpan<'ecx, 'mir, 'tcx>,
+    threads: &'ecx ThreadManager<'mir, 'tcx>,
+}
+
+pub struct DiagnosticCx<'span, 'history, 'ecx, 'mir, 'tcx> {
+    operation: Operation,
+    // 'span and 'history cannot be merged, since when we call `unbuild` we need
+    // to return the exact 'span that was used when calling `build`.
+    current_span: &'span mut CurrentSpan<'ecx, 'mir, 'tcx>,
+    threads: &'ecx ThreadManager<'mir, 'tcx>,
+    history: &'history mut AllocHistory,
+    offset: Size,
+}
+
+impl<'span, 'ecx, 'mir, 'tcx> DiagnosticCxBuilder<'span, 'ecx, 'mir, 'tcx> {
+    pub fn build<'history>(
+        self,
+        history: &'history mut AllocHistory,
+        offset: Size,
+    ) -> DiagnosticCx<'span, 'history, 'ecx, 'mir, 'tcx> {
+        DiagnosticCx {
+            operation: self.operation,
+            current_span: self.current_span,
+            threads: self.threads,
+            history,
+            offset,
+        }
+    }
+
+    pub fn retag(
+        current_span: &'span mut CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+        cause: RetagCause,
+        new_tag: SbTag,
+        orig_tag: ProvenanceExtra,
+        range: AllocRange,
+    ) -> Self {
+        let operation =
+            Operation::Retag(RetagOp { cause, new_tag, orig_tag, range, permission: None });
+
+        DiagnosticCxBuilder { current_span, threads, operation }
+    }
+
+    pub fn read(
+        current_span: &'span mut CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+        tag: ProvenanceExtra,
+        range: AllocRange,
+    ) -> Self {
+        let operation = Operation::Access(AccessOp { kind: AccessKind::Read, tag, range });
+        DiagnosticCxBuilder { current_span, threads, operation }
+    }
+
+    pub fn write(
+        current_span: &'span mut CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+        tag: ProvenanceExtra,
+        range: AllocRange,
+    ) -> Self {
+        let operation = Operation::Access(AccessOp { kind: AccessKind::Write, tag, range });
+        DiagnosticCxBuilder { current_span, threads, operation }
+    }
+
+    pub fn dealloc(
+        current_span: &'span mut CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+        tag: ProvenanceExtra,
+    ) -> Self {
+        let operation = Operation::Dealloc(DeallocOp { tag });
+        DiagnosticCxBuilder { current_span, threads, operation }
+    }
+}
+
+impl<'span, 'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'span, 'history, 'ecx, 'mir, 'tcx> {
+    pub fn unbuild(self) -> DiagnosticCxBuilder<'span, 'ecx, 'mir, 'tcx> {
+        DiagnosticCxBuilder {
+            operation: self.operation,
+            current_span: self.current_span,
+            threads: self.threads,
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+enum Operation {
+    Retag(RetagOp),
+    Access(AccessOp),
+    Dealloc(DeallocOp),
+}
+
+#[derive(Debug, Clone)]
+struct RetagOp {
+    cause: RetagCause,
+    new_tag: SbTag,
+    orig_tag: ProvenanceExtra,
+    range: AllocRange,
+    permission: Option<Permission>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum RetagCause {
+    Normal,
+    FnReturn,
+    FnEntry,
+    TwoPhase,
+}
+
+#[derive(Debug, Clone)]
+struct AccessOp {
+    kind: AccessKind,
+    tag: ProvenanceExtra,
+    range: AllocRange,
+}
+
+#[derive(Debug, Clone)]
+struct DeallocOp {
+    tag: ProvenanceExtra,
+}
+
+impl AllocHistory {
+    pub fn new(id: AllocId, item: Item, current_span: &mut CurrentSpan<'_, '_, '_>) -> Self {
+        Self {
+            id,
+            base: (item, current_span.get()),
+            creations: SmallVec::new(),
+            invalidations: SmallVec::new(),
+            protectors: SmallVec::new(),
+        }
+    }
+}
+
+impl<'span, 'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'span, 'history, 'ecx, 'mir, 'tcx> {
+    pub fn start_grant(&mut self, perm: Permission) {
+        let Operation::Retag(op) = &mut self.operation else {
+            unreachable!("start_grant must only be called during a retag, this is: {:?}", self.operation)
+        };
+        op.permission = Some(perm);
+
+        let last_creation = &mut self.history.creations.last_mut().unwrap();
+        match last_creation.retag.permission {
+            None => {
+                last_creation.retag.permission = Some(perm);
+            }
+            Some(previous) =>
+                if previous != perm {
+                    // 'Split up' the creation event.
+                    let previous_range = last_creation.retag.range;
+                    last_creation.retag.range = alloc_range(previous_range.start, self.offset);
+                    let mut new_event = last_creation.clone();
+                    new_event.retag.range = alloc_range(self.offset, previous_range.end());
+                    new_event.retag.permission = Some(perm);
+                    self.history.creations.push(new_event);
+                },
+        }
+    }
+
+    pub fn log_creation(&mut self) {
+        let Operation::Retag(op) = &self.operation else {
+            unreachable!("log_creation must only be called during a retag")
+        };
+        self.history.creations.push(Creation { retag: op.clone(), span: self.current_span.get() });
+    }
+
+    pub fn log_invalidation(&mut self, tag: SbTag) {
+        let mut span = self.current_span.get();
+        let (range, cause) = match &self.operation {
+            Operation::Retag(RetagOp { cause, range, permission, .. }) => {
+                if *cause == RetagCause::FnEntry {
+                    span = self.current_span.get_parent();
+                }
+                (*range, InvalidationCause::Retag(permission.unwrap(), *cause))
+            }
+            Operation::Access(AccessOp { kind, range, .. }) =>
+                (*range, InvalidationCause::Access(*kind)),
+            _ => unreachable!("Tags can only be invalidated during a retag or access"),
+        };
+        self.history.invalidations.push(Invalidation { tag, range, span, cause });
+    }
+
+    pub fn log_protector(&mut self) {
+        let Operation::Retag(op) = &self.operation else {
+            unreachable!("Protectors can only be created during a retag")
+        };
+        self.history.protectors.push(Protection { tag: op.new_tag, span: self.current_span.get() });
+    }
+
+    pub fn get_logs_relevant_to(
+        &self,
+        tag: SbTag,
+        protector_tag: Option<SbTag>,
+    ) -> Option<TagHistory> {
+        let Some(created) = self.history
+            .creations
+            .iter()
+            .rev()
+            .find_map(|event| {
+                // First, look for a Creation event where the tag and the offset matches. This
+                // ensrues that we pick the right Creation event when a retag isn't uniform due to
+                // Freeze.
+                let range = event.retag.range;
+                if event.retag.new_tag == tag
+                    && self.offset >= range.start
+                    && self.offset < (range.start + range.size)
+                {
+                    Some(event.generate_diagnostic())
+                } else {
+                    None
+                }
+            })
+            .or_else(|| {
+                // If we didn't find anything with a matching offset, just return the event where
+                // the tag was created. This branch is hit when we use a tag at an offset that
+                // doesn't have the tag.
+                self.history.creations.iter().rev().find_map(|event| {
+                    if event.retag.new_tag == tag {
+                        Some(event.generate_diagnostic())
+                    } else {
+                        None
+                    }
+                })
+            }).or_else(|| {
+                // If we didn't find a retag that created this tag, it might be the base tag of
+                // this allocation.
+                if self.history.base.0.tag() == tag {
+                    Some((
+                        format!("{:?} was created here, as the base tag for {:?}", tag, self.history.id),
+                        self.history.base.1.data()
+                    ))
+                } else {
+                    None
+                }
+            }) else {
+                // But if we don't have a creation event, this is related to a wildcard, and there
+                // is really nothing we can do to help.
+                return None;
+            };
+
+        let invalidated = self.history.invalidations.iter().rev().find_map(|event| {
+            if event.tag == tag { Some(event.generate_diagnostic()) } else { None }
+        });
+
+        let protected = protector_tag
+            .and_then(|protector| {
+                self.history.protectors.iter().find(|protection| protection.tag == protector)
+            })
+            .map(|protection| {
+                let protected_tag = protection.tag;
+                (format!("{protected_tag:?} is this argument"), protection.span.data())
+            });
+
+        Some(TagHistory { created, invalidated, protected })
+    }
+
+    /// Report a descriptive error when `new` could not be granted from `derived_from`.
+    #[inline(never)] // This is only called on fatal code paths
+    pub fn grant_error(&self, perm: Permission, stack: &Stack) -> InterpError<'tcx> {
+        let Operation::Retag(op) = &self.operation else {
+            unreachable!("grant_error should only be called during a retag")
+        };
+        let action = format!(
+            "trying to retag from {:?} for {:?} permission at {:?}[{:#x}]",
+            op.orig_tag,
+            perm,
+            self.history.id,
+            self.offset.bytes(),
+        );
+        err_sb_ub(
+            format!("{}{}", action, error_cause(stack, op.orig_tag)),
+            Some(operation_summary(&op.cause.summary(), self.history.id, op.range)),
+            op.orig_tag.and_then(|orig_tag| self.get_logs_relevant_to(orig_tag, None)),
+        )
+    }
+
+    /// Report a descriptive error when `access` is not permitted based on `tag`.
+    #[inline(never)] // This is only called on fatal code paths
+    pub fn access_error(&self, stack: &Stack) -> InterpError<'tcx> {
+        let Operation::Access(op) = &self.operation  else {
+            unreachable!("access_error should only be called during an access")
+        };
+        let action = format!(
+            "attempting a {access} using {tag:?} at {alloc_id:?}[{offset:#x}]",
+            access = op.kind,
+            tag = op.tag,
+            alloc_id = self.history.id,
+            offset = self.offset.bytes(),
+        );
+        err_sb_ub(
+            format!("{}{}", action, error_cause(stack, op.tag)),
+            Some(operation_summary("an access", self.history.id, op.range)),
+            op.tag.and_then(|tag| self.get_logs_relevant_to(tag, None)),
+        )
+    }
+
+    #[inline(never)] // This is only called on fatal code paths
+    pub fn protector_error(&self, item: &Item) -> InterpError<'tcx> {
+        let call_id = self
+            .threads
+            .all_stacks()
+            .flatten()
+            .map(|frame| {
+                frame.extra.stacked_borrows.as_ref().expect("we should have Stacked Borrows data")
+            })
+            .find(|frame| frame.protected_tags.contains(&item.tag()))
+            .map(|frame| frame.call_id)
+            .unwrap(); // FIXME: Surely we should find something, but a panic seems wrong here?
+        match self.operation {
+            Operation::Dealloc(_) =>
+                err_sb_ub(
+                    format!(
+                        "deallocating while item {:?} is protected by call {:?}",
+                        item, call_id
+                    ),
+                    None,
+                    None,
+                ),
+            Operation::Retag(RetagOp { orig_tag: tag, .. })
+            | Operation::Access(AccessOp { tag, .. }) =>
+                err_sb_ub(
+                    format!(
+                        "not granting access to tag {:?} because that would remove {:?} which is protected because it is an argument of call {:?}",
+                        tag, item, call_id
+                    ),
+                    None,
+                    tag.and_then(|tag| self.get_logs_relevant_to(tag, Some(item.tag()))),
+                ),
+        }
+    }
+
+    #[inline(never)] // This is only called on fatal code paths
+    pub fn dealloc_error(&self) -> InterpError<'tcx> {
+        let Operation::Dealloc(op) = &self.operation else {
+            unreachable!("dealloc_error should only be called during a deallocation")
+        };
+        err_sb_ub(
+            format!(
+                "no item granting write access for deallocation to tag {:?} at {:?} found in borrow stack",
+                op.tag, self.history.id,
+            ),
+            None,
+            op.tag.and_then(|tag| self.get_logs_relevant_to(tag, None)),
+        )
+    }
+
+    #[inline(never)]
+    pub fn check_tracked_tag_popped(&self, item: &Item, global: &GlobalStateInner) {
+        if !global.tracked_pointer_tags.contains(&item.tag()) {
+            return;
+        }
+        let summary = match self.operation {
+            Operation::Dealloc(_) => None,
+            Operation::Access(AccessOp { kind, tag, .. }) => Some((tag, kind)),
+            Operation::Retag(RetagOp { orig_tag, permission, .. }) => {
+                let kind = match permission
+                    .expect("start_grant should set the current permission before popping a tag")
+                {
+                    Permission::SharedReadOnly => AccessKind::Read,
+                    Permission::Unique => AccessKind::Write,
+                    Permission::SharedReadWrite | Permission::Disabled => {
+                        panic!("Only SharedReadOnly and Unique retags can pop tags");
+                    }
+                };
+                Some((orig_tag, kind))
+            }
+        };
+        self.current_span
+            .machine()
+            .emit_diagnostic(NonHaltingDiagnostic::PoppedPointerTag(*item, summary));
+    }
+}
+
+fn operation_summary(operation: &str, alloc_id: AllocId, alloc_range: AllocRange) -> String {
+    format!("this error occurs as part of {operation} at {alloc_id:?}{alloc_range:?}")
+}
+
+fn error_cause(stack: &Stack, prov_extra: ProvenanceExtra) -> &'static str {
+    if let ProvenanceExtra::Concrete(tag) = prov_extra {
+        if (0..stack.len())
+            .map(|i| stack.get(i).unwrap())
+            .any(|item| item.tag() == tag && item.perm() != Permission::Disabled)
+        {
+            ", but that tag only grants SharedReadOnly permission for this location"
+        } else {
+            ", but that tag does not exist in the borrow stack for this location"
+        }
+    } else {
+        ", but no exposed tags have suitable permission in the borrow stack for this location"
+    }
+}
+
+impl RetagCause {
+    fn summary(&self) -> String {
+        match self {
+            RetagCause::Normal => "retag",
+            RetagCause::FnEntry => "FnEntry retag",
+            RetagCause::FnReturn => "FnReturn retag",
+            RetagCause::TwoPhase => "two-phase retag",
+        }
+        .to_string()
+    }
+}
diff --git a/src/tools/miri/src/stacked_borrows/item.rs b/src/tools/miri/src/stacked_borrows/item.rs
new file mode 100644
index 000000000000..709b27d191b2
--- /dev/null
+++ b/src/tools/miri/src/stacked_borrows/item.rs
@@ -0,0 +1,104 @@
+use crate::stacked_borrows::SbTag;
+use std::fmt;
+use std::num::NonZeroU64;
+
+/// An item in the per-location borrow stack.
+#[derive(Copy, Clone, Hash, PartialEq, Eq)]
+pub struct Item(u64);
+
+// An Item contains 3 bitfields:
+// * Bits 0-61 store an SbTag
+// * Bits 61-63 store a Permission
+// * Bit 64 stores a flag which indicates if we have a protector
+const TAG_MASK: u64 = u64::MAX >> 3;
+const PERM_MASK: u64 = 0x3 << 61;
+const PROTECTED_MASK: u64 = 0x1 << 63;
+
+const PERM_SHIFT: u64 = 61;
+const PROTECTED_SHIFT: u64 = 63;
+
+impl Item {
+    pub fn new(tag: SbTag, perm: Permission, protected: bool) -> Self {
+        assert!(tag.0.get() <= TAG_MASK);
+        let packed_tag = tag.0.get();
+        let packed_perm = perm.to_bits() << PERM_SHIFT;
+        let packed_protected = u64::from(protected) << PROTECTED_SHIFT;
+
+        let new = Self(packed_tag | packed_perm | packed_protected);
+
+        debug_assert!(new.tag() == tag);
+        debug_assert!(new.perm() == perm);
+        debug_assert!(new.protected() == protected);
+
+        new
+    }
+
+    /// The pointers the permission is granted to.
+    pub fn tag(self) -> SbTag {
+        SbTag(NonZeroU64::new(self.0 & TAG_MASK).unwrap())
+    }
+
+    /// The permission this item grants.
+    pub fn perm(self) -> Permission {
+        Permission::from_bits((self.0 & PERM_MASK) >> PERM_SHIFT)
+    }
+
+    /// Whether or not there is a protector for this tag
+    pub fn protected(self) -> bool {
+        self.0 & PROTECTED_MASK > 0
+    }
+
+    /// Set the Permission stored in this Item
+    pub fn set_permission(&mut self, perm: Permission) {
+        // Clear the current set permission
+        self.0 &= !PERM_MASK;
+        // Write Permission::Disabled to the Permission bits
+        self.0 |= perm.to_bits() << PERM_SHIFT;
+    }
+}
+
+impl fmt::Debug for Item {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "[{:?} for {:?}]", self.perm(), self.tag())
+    }
+}
+
+/// Indicates which permission is granted (by this item to some pointers)
+#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
+pub enum Permission {
+    /// Grants unique mutable access.
+    Unique,
+    /// Grants shared mutable access.
+    SharedReadWrite,
+    /// Grants shared read-only access.
+    SharedReadOnly,
+    /// Grants no access, but separates two groups of SharedReadWrite so they are not
+    /// all considered mutually compatible.
+    Disabled,
+}
+
+impl Permission {
+    const UNIQUE: u64 = 0;
+    const SHARED_READ_WRITE: u64 = 1;
+    const SHARED_READ_ONLY: u64 = 2;
+    const DISABLED: u64 = 3;
+
+    fn to_bits(self) -> u64 {
+        match self {
+            Permission::Unique => Self::UNIQUE,
+            Permission::SharedReadWrite => Self::SHARED_READ_WRITE,
+            Permission::SharedReadOnly => Self::SHARED_READ_ONLY,
+            Permission::Disabled => Self::DISABLED,
+        }
+    }
+
+    fn from_bits(perm: u64) -> Self {
+        match perm {
+            Self::UNIQUE => Permission::Unique,
+            Self::SHARED_READ_WRITE => Permission::SharedReadWrite,
+            Self::SHARED_READ_ONLY => Permission::SharedReadOnly,
+            Self::DISABLED => Permission::Disabled,
+            _ => unreachable!(),
+        }
+    }
+}
diff --git a/src/tools/miri/src/stacked_borrows/mod.rs b/src/tools/miri/src/stacked_borrows/mod.rs
new file mode 100644
index 000000000000..f7f4b1357f10
--- /dev/null
+++ b/src/tools/miri/src/stacked_borrows/mod.rs
@@ -0,0 +1,1087 @@
+//! Implements "Stacked Borrows".  See <https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md>
+//! for further information.
+
+use log::trace;
+use std::cell::RefCell;
+use std::cmp;
+use std::fmt;
+use std::num::NonZeroU64;
+
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_hir::Mutability;
+use rustc_middle::mir::RetagKind;
+use rustc_middle::ty::{
+    self,
+    layout::{HasParamEnv, LayoutOf},
+    Ty,
+};
+use rustc_span::DUMMY_SP;
+use rustc_target::abi::Size;
+use smallvec::SmallVec;
+
+use crate::*;
+
+pub mod diagnostics;
+use diagnostics::{AllocHistory, DiagnosticCx, DiagnosticCxBuilder, RetagCause, TagHistory};
+
+mod item;
+pub use item::{Item, Permission};
+mod stack;
+pub use stack::Stack;
+
+pub type CallId = NonZeroU64;
+
+// Even reading memory can have effects on the stack, so we need a `RefCell` here.
+pub type AllocExtra = RefCell<Stacks>;
+
+/// Tracking pointer provenance
+#[derive(Copy, Clone, Hash, PartialEq, Eq)]
+pub struct SbTag(NonZeroU64);
+
+impl SbTag {
+    pub fn new(i: u64) -> Option<Self> {
+        NonZeroU64::new(i).map(SbTag)
+    }
+
+    // The default to be used when SB is disabled
+    pub fn default() -> Self {
+        Self::new(1).unwrap()
+    }
+}
+
+impl fmt::Debug for SbTag {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "<{}>", self.0)
+    }
+}
+
+#[derive(Debug)]
+pub struct FrameExtra {
+    /// The ID of the call this frame corresponds to.
+    call_id: CallId,
+
+    /// If this frame is protecting any tags, they are listed here. We use this list to do
+    /// incremental updates of the global list of protected tags stored in the
+    /// `stacked_borrows::GlobalState` upon function return, and if we attempt to pop a protected
+    /// tag, to identify which call is responsible for protecting the tag.
+    /// See `Stack::item_popped` for more explanation.
+    ///
+    /// This will contain one tag per reference passed to the function, so
+    /// a size of 2 is enough for the vast majority of functions.
+    protected_tags: SmallVec<[SbTag; 2]>,
+}
+
+/// Extra per-allocation state.
+#[derive(Clone, Debug)]
+pub struct Stacks {
+    // Even reading memory can have effects on the stack, so we need a `RefCell` here.
+    stacks: RangeMap<Stack>,
+    /// Stores past operations on this allocation
+    history: AllocHistory,
+    /// The set of tags that have been exposed inside this allocation.
+    exposed_tags: FxHashSet<SbTag>,
+    /// Whether this memory has been modified since the last time the tag GC ran
+    modified_since_last_gc: bool,
+}
+
+/// Extra global state, available to the memory access hooks.
+#[derive(Debug)]
+pub struct GlobalStateInner {
+    /// Next unused pointer ID (tag).
+    next_ptr_tag: SbTag,
+    /// Table storing the "base" tag for each allocation.
+    /// The base tag is the one used for the initial pointer.
+    /// We need this in a separate table to handle cyclic statics.
+    base_ptr_tags: FxHashMap<AllocId, SbTag>,
+    /// Next unused call ID (for protectors).
+    next_call_id: CallId,
+    /// All currently protected tags.
+    /// An item is protected if its tag is in this set, *and* it has the "protected" bit set.
+    /// We add tags to this when they are created with a protector in `reborrow`, and
+    /// we remove tags from this when the call which is protecting them returns, in
+    /// `GlobalStateInner::end_call`. See `Stack::item_popped` for more details.
+    protected_tags: FxHashSet<SbTag>,
+    /// The pointer ids to trace
+    tracked_pointer_tags: FxHashSet<SbTag>,
+    /// The call ids to trace
+    tracked_call_ids: FxHashSet<CallId>,
+    /// Whether to recurse into datatypes when searching for pointers to retag.
+    retag_fields: bool,
+}
+
+/// We need interior mutable access to the global state.
+pub type GlobalState = RefCell<GlobalStateInner>;
+
+/// Indicates which kind of access is being performed.
+#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
+pub enum AccessKind {
+    Read,
+    Write,
+}
+
+impl fmt::Display for AccessKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            AccessKind::Read => write!(f, "read access"),
+            AccessKind::Write => write!(f, "write access"),
+        }
+    }
+}
+
+/// Indicates which kind of reference is being created.
+/// Used by high-level `reborrow` to compute which permissions to grant to the
+/// new pointer.
+#[derive(Copy, Clone, Hash, PartialEq, Eq)]
+pub enum RefKind {
+    /// `&mut` and `Box`.
+    Unique { two_phase: bool },
+    /// `&` with or without interior mutability.
+    Shared,
+    /// `*mut`/`*const` (raw pointers).
+    Raw { mutable: bool },
+}
+
+impl fmt::Display for RefKind {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            RefKind::Unique { two_phase: false } => write!(f, "unique reference"),
+            RefKind::Unique { two_phase: true } => write!(f, "unique reference (two-phase)"),
+            RefKind::Shared => write!(f, "shared reference"),
+            RefKind::Raw { mutable: true } => write!(f, "raw (mutable) pointer"),
+            RefKind::Raw { mutable: false } => write!(f, "raw (constant) pointer"),
+        }
+    }
+}
+
+/// Utilities for initialization and ID generation
+impl GlobalStateInner {
+    pub fn new(
+        tracked_pointer_tags: FxHashSet<SbTag>,
+        tracked_call_ids: FxHashSet<CallId>,
+        retag_fields: bool,
+    ) -> Self {
+        GlobalStateInner {
+            next_ptr_tag: SbTag(NonZeroU64::new(1).unwrap()),
+            base_ptr_tags: FxHashMap::default(),
+            next_call_id: NonZeroU64::new(1).unwrap(),
+            protected_tags: FxHashSet::default(),
+            tracked_pointer_tags,
+            tracked_call_ids,
+            retag_fields,
+        }
+    }
+
+    /// Generates a new pointer tag. Remember to also check track_pointer_tags and log its creation!
+    fn new_ptr(&mut self) -> SbTag {
+        let id = self.next_ptr_tag;
+        self.next_ptr_tag = SbTag(NonZeroU64::new(id.0.get() + 1).unwrap());
+        id
+    }
+
+    pub fn new_frame(&mut self, machine: &MiriMachine<'_, '_>) -> FrameExtra {
+        let call_id = self.next_call_id;
+        trace!("new_frame: Assigning call ID {}", call_id);
+        if self.tracked_call_ids.contains(&call_id) {
+            machine.emit_diagnostic(NonHaltingDiagnostic::CreatedCallId(call_id));
+        }
+        self.next_call_id = NonZeroU64::new(call_id.get() + 1).unwrap();
+        FrameExtra { call_id, protected_tags: SmallVec::new() }
+    }
+
+    pub fn end_call(&mut self, frame: &machine::FrameData<'_>) {
+        for tag in &frame
+            .stacked_borrows
+            .as_ref()
+            .expect("we should have Stacked Borrows data")
+            .protected_tags
+        {
+            self.protected_tags.remove(tag);
+        }
+    }
+
+    pub fn base_ptr_tag(&mut self, id: AllocId, machine: &MiriMachine<'_, '_>) -> SbTag {
+        self.base_ptr_tags.get(&id).copied().unwrap_or_else(|| {
+            let tag = self.new_ptr();
+            if self.tracked_pointer_tags.contains(&tag) {
+                machine.emit_diagnostic(NonHaltingDiagnostic::CreatedPointerTag(tag.0, None));
+            }
+            trace!("New allocation {:?} has base tag {:?}", id, tag);
+            self.base_ptr_tags.try_insert(id, tag).unwrap();
+            tag
+        })
+    }
+}
+
+/// Error reporting
+pub fn err_sb_ub<'tcx>(
+    msg: String,
+    help: Option<String>,
+    history: Option<TagHistory>,
+) -> InterpError<'tcx> {
+    err_machine_stop!(TerminationInfo::StackedBorrowsUb { msg, help, history })
+}
+
+// # Stacked Borrows Core Begin
+
+/// We need to make at least the following things true:
+///
+/// U1: After creating a `Uniq`, it is at the top.
+/// U2: If the top is `Uniq`, accesses must be through that `Uniq` or remove it it.
+/// U3: If an access happens with a `Uniq`, it requires the `Uniq` to be in the stack.
+///
+/// F1: After creating a `&`, the parts outside `UnsafeCell` have our `SharedReadOnly` on top.
+/// F2: If a write access happens, it pops the `SharedReadOnly`.  This has three pieces:
+///     F2a: If a write happens granted by an item below our `SharedReadOnly`, the `SharedReadOnly`
+///          gets popped.
+///     F2b: No `SharedReadWrite` or `Unique` will ever be added on top of our `SharedReadOnly`.
+/// F3: If an access happens with an `&` outside `UnsafeCell`,
+///     it requires the `SharedReadOnly` to still be in the stack.
+
+/// Core relation on `Permission` to define which accesses are allowed
+impl Permission {
+    /// This defines for a given permission, whether it permits the given kind of access.
+    fn grants(self, access: AccessKind) -> bool {
+        // Disabled grants nothing. Otherwise, all items grant read access, and except for SharedReadOnly they grant write access.
+        self != Permission::Disabled
+            && (access == AccessKind::Read || self != Permission::SharedReadOnly)
+    }
+}
+
+/// Core per-location operations: access, dealloc, reborrow.
+impl<'tcx> Stack {
+    /// Find the first write-incompatible item above the given one --
+    /// i.e, find the height to which the stack will be truncated when writing to `granting`.
+    fn find_first_write_incompatible(&self, granting: usize) -> usize {
+        let perm = self.get(granting).unwrap().perm();
+        match perm {
+            Permission::SharedReadOnly => bug!("Cannot use SharedReadOnly for writing"),
+            Permission::Disabled => bug!("Cannot use Disabled for anything"),
+            Permission::Unique => {
+                // On a write, everything above us is incompatible.
+                granting + 1
+            }
+            Permission::SharedReadWrite => {
+                // The SharedReadWrite *just* above us are compatible, to skip those.
+                let mut idx = granting + 1;
+                while let Some(item) = self.get(idx) {
+                    if item.perm() == Permission::SharedReadWrite {
+                        // Go on.
+                        idx += 1;
+                    } else {
+                        // Found first incompatible!
+                        break;
+                    }
+                }
+                idx
+            }
+        }
+    }
+
+    /// Check if the given item is protected.
+    ///
+    /// The `provoking_access` argument is only used to produce diagnostics.
+    /// It is `Some` when we are granting the contained access for said tag, and it is
+    /// `None` during a deallocation.
+    /// Within `provoking_access, the `AllocRange` refers the entire operation, and
+    /// the `Size` refers to the specific location in the `AllocRange` that we are
+    /// currently checking.
+    fn item_popped(
+        item: &Item,
+        global: &GlobalStateInner,
+        dcx: &mut DiagnosticCx<'_, '_, '_, '_, 'tcx>,
+    ) -> InterpResult<'tcx> {
+        if !global.tracked_pointer_tags.is_empty() {
+            dcx.check_tracked_tag_popped(item, global);
+        }
+
+        if !item.protected() {
+            return Ok(());
+        }
+
+        // We store tags twice, once in global.protected_tags and once in each call frame.
+        // We do this because consulting a single global set in this function is faster
+        // than attempting to search all call frames in the program for the `FrameExtra`
+        // (if any) which is protecting the popped tag.
+        //
+        // This duplication trades off making `end_call` slower to make this function faster. This
+        // trade-off is profitable in practice for a combination of two reasons.
+        // 1. A single protected tag can (and does in some programs) protect thousands of `Item`s.
+        //    Therefore, adding overhead in function call/return is profitable even if it only
+        //    saves a little work in this function.
+        // 2. Most frames protect only one or two tags. So this duplicative global turns a search
+        //    which ends up about linear in the number of protected tags in the program into a
+        //    constant time check (and a slow linear, because the tags in the frames aren't contiguous).
+        if global.protected_tags.contains(&item.tag()) {
+            return Err(dcx.protector_error(item).into());
+        }
+        Ok(())
+    }
+
+    /// Test if a memory `access` using pointer tagged `tag` is granted.
+    /// If yes, return the index of the item that granted it.
+    /// `range` refers the entire operation, and `offset` refers to the specific offset into the
+    /// allocation that we are currently checking.
+    fn access(
+        &mut self,
+        access: AccessKind,
+        tag: ProvenanceExtra,
+        global: &mut GlobalStateInner,
+        dcx: &mut DiagnosticCx<'_, '_, '_, '_, 'tcx>,
+        exposed_tags: &FxHashSet<SbTag>,
+    ) -> InterpResult<'tcx> {
+        // Two main steps: Find granting item, remove incompatible items above.
+
+        // Step 1: Find granting item.
+        let granting_idx =
+            self.find_granting(access, tag, exposed_tags).map_err(|_| dcx.access_error(self))?;
+
+        // Step 2: Remove incompatible items above them.  Make sure we do not remove protected
+        // items.  Behavior differs for reads and writes.
+        // In case of wildcards/unknown matches, we remove everything that is *definitely* gone.
+        if access == AccessKind::Write {
+            // Remove everything above the write-compatible items, like a proper stack. This makes sure read-only and unique
+            // pointers become invalid on write accesses (ensures F2a, and ensures U2 for write accesses).
+            let first_incompatible_idx = if let Some(granting_idx) = granting_idx {
+                // The granting_idx *might* be approximate, but any lower idx would remove more
+                // things. Even if this is a Unique and the lower idx is an SRW (which removes
+                // less), there is an SRW group boundary here so strictly more would get removed.
+                self.find_first_write_incompatible(granting_idx)
+            } else {
+                // We are writing to something in the unknown part.
+                // There is a SRW group boundary between the unknown and the known, so everything is incompatible.
+                0
+            };
+            self.pop_items_after(first_incompatible_idx, |item| {
+                Stack::item_popped(&item, global, dcx)?;
+                dcx.log_invalidation(item.tag());
+                Ok(())
+            })?;
+        } else {
+            // On a read, *disable* all `Unique` above the granting item.  This ensures U2 for read accesses.
+            // The reason this is not following the stack discipline (by removing the first Unique and
+            // everything on top of it) is that in `let raw = &mut *x as *mut _; let _val = *x;`, the second statement
+            // would pop the `Unique` from the reborrow of the first statement, and subsequently also pop the
+            // `SharedReadWrite` for `raw`.
+            // This pattern occurs a lot in the standard library: create a raw pointer, then also create a shared
+            // reference and use that.
+            // We *disable* instead of removing `Unique` to avoid "connecting" two neighbouring blocks of SRWs.
+            let first_incompatible_idx = if let Some(granting_idx) = granting_idx {
+                // The granting_idx *might* be approximate, but any lower idx would disable more things.
+                granting_idx + 1
+            } else {
+                // We are reading from something in the unknown part. That means *all* `Unique` we know about are dead now.
+                0
+            };
+            self.disable_uniques_starting_at(first_incompatible_idx, |item| {
+                Stack::item_popped(&item, global, dcx)?;
+                dcx.log_invalidation(item.tag());
+                Ok(())
+            })?;
+        }
+
+        // If this was an approximate action, we now collapse everything into an unknown.
+        if granting_idx.is_none() || matches!(tag, ProvenanceExtra::Wildcard) {
+            // Compute the upper bound of the items that remain.
+            // (This is why we did all the work above: to reduce the items we have to consider here.)
+            let mut max = NonZeroU64::new(1).unwrap();
+            for i in 0..self.len() {
+                let item = self.get(i).unwrap();
+                // Skip disabled items, they cannot be matched anyway.
+                if !matches!(item.perm(), Permission::Disabled) {
+                    // We are looking for a strict upper bound, so add 1 to this tag.
+                    max = cmp::max(item.tag().0.checked_add(1).unwrap(), max);
+                }
+            }
+            if let Some(unk) = self.unknown_bottom() {
+                max = cmp::max(unk.0, max);
+            }
+            // Use `max` as new strict upper bound for everything.
+            trace!(
+                "access: forgetting stack to upper bound {max} due to wildcard or unknown access"
+            );
+            self.set_unknown_bottom(SbTag(max));
+        }
+
+        // Done.
+        Ok(())
+    }
+
+    /// Deallocate a location: Like a write access, but also there must be no
+    /// active protectors at all because we will remove all items.
+    fn dealloc(
+        &mut self,
+        tag: ProvenanceExtra,
+        global: &GlobalStateInner,
+        dcx: &mut DiagnosticCx<'_, '_, '_, '_, 'tcx>,
+        exposed_tags: &FxHashSet<SbTag>,
+    ) -> InterpResult<'tcx> {
+        // Step 1: Make sure there is a granting item.
+        self.find_granting(AccessKind::Write, tag, exposed_tags)
+            .map_err(|_| dcx.dealloc_error())?;
+
+        // Step 2: Consider all items removed. This checks for protectors.
+        for idx in (0..self.len()).rev() {
+            let item = self.get(idx).unwrap();
+            Stack::item_popped(&item, global, dcx)?;
+        }
+
+        Ok(())
+    }
+
+    /// Derive a new pointer from one with the given tag.
+    /// `weak` controls whether this operation is weak or strong: weak granting does not act as
+    /// an access, and they add the new item directly on top of the one it is derived
+    /// from instead of all the way at the top of the stack.
+    /// `range` refers the entire operation, and `offset` refers to the specific location in
+    /// `range` that we are currently checking.
+    fn grant(
+        &mut self,
+        derived_from: ProvenanceExtra,
+        new: Item,
+        global: &mut GlobalStateInner,
+        dcx: &mut DiagnosticCx<'_, '_, '_, '_, 'tcx>,
+        exposed_tags: &FxHashSet<SbTag>,
+    ) -> InterpResult<'tcx> {
+        dcx.start_grant(new.perm());
+
+        // Figure out which access `perm` corresponds to.
+        let access =
+            if new.perm().grants(AccessKind::Write) { AccessKind::Write } else { AccessKind::Read };
+
+        // Now we figure out which item grants our parent (`derived_from`) this kind of access.
+        // We use that to determine where to put the new item.
+        let granting_idx = self
+            .find_granting(access, derived_from, exposed_tags)
+            .map_err(|_| dcx.grant_error(new.perm(), self))?;
+
+        // Compute where to put the new item.
+        // Either way, we ensure that we insert the new item in a way such that between
+        // `derived_from` and the new one, there are only items *compatible with* `derived_from`.
+        let new_idx = if new.perm() == Permission::SharedReadWrite {
+            assert!(
+                access == AccessKind::Write,
+                "this case only makes sense for stack-like accesses"
+            );
+
+            let (Some(granting_idx), ProvenanceExtra::Concrete(_)) = (granting_idx, derived_from) else {
+                // The parent is a wildcard pointer or matched the unknown bottom.
+                // This is approximate. Nobody knows what happened, so forget everything.
+                // The new thing is SRW anyway, so we cannot push it "on top of the unkown part"
+                // (for all we know, it might join an SRW group inside the unknown).
+                trace!("reborrow: forgetting stack entirely due to SharedReadWrite reborrow from wildcard or unknown");
+                self.set_unknown_bottom(global.next_ptr_tag);
+                return Ok(());
+            };
+
+            // SharedReadWrite can coexist with "existing loans", meaning they don't act like a write
+            // access.  Instead of popping the stack, we insert the item at the place the stack would
+            // be popped to (i.e., we insert it above all the write-compatible items).
+            // This ensures F2b by adding the new item below any potentially existing `SharedReadOnly`.
+            self.find_first_write_incompatible(granting_idx)
+        } else {
+            // A "safe" reborrow for a pointer that actually expects some aliasing guarantees.
+            // Here, creating a reference actually counts as an access.
+            // This ensures F2b for `Unique`, by removing offending `SharedReadOnly`.
+            self.access(access, derived_from, global, dcx, exposed_tags)?;
+
+            // We insert "as far up as possible": We know only compatible items are remaining
+            // on top of `derived_from`, and we want the new item at the top so that we
+            // get the strongest possible guarantees.
+            // This ensures U1 and F1.
+            self.len()
+        };
+
+        // Put the new item there.
+        trace!("reborrow: adding item {:?}", new);
+        self.insert(new_idx, new);
+        Ok(())
+    }
+}
+// # Stacked Borrows Core End
+
+/// Integration with the SbTag garbage collector
+impl Stacks {
+    pub fn remove_unreachable_tags(&mut self, live_tags: &FxHashSet<SbTag>) {
+        if self.modified_since_last_gc {
+            for stack in self.stacks.iter_mut_all() {
+                if stack.len() > 64 {
+                    stack.retain(live_tags);
+                }
+            }
+            self.modified_since_last_gc = false;
+        }
+    }
+}
+
+/// Map per-stack operations to higher-level per-location-range operations.
+impl<'tcx> Stacks {
+    /// Creates a new stack with an initial tag. For diagnostic purposes, we also need to know
+    /// the [`AllocId`] of the allocation this is associated with.
+    fn new(
+        size: Size,
+        perm: Permission,
+        tag: SbTag,
+        id: AllocId,
+        current_span: &mut CurrentSpan<'_, '_, '_>,
+    ) -> Self {
+        let item = Item::new(tag, perm, false);
+        let stack = Stack::new(item);
+
+        Stacks {
+            stacks: RangeMap::new(size, stack),
+            history: AllocHistory::new(id, item, current_span),
+            exposed_tags: FxHashSet::default(),
+            modified_since_last_gc: false,
+        }
+    }
+
+    /// Call `f` on every stack in the range.
+    fn for_each(
+        &mut self,
+        range: AllocRange,
+        mut dcx_builder: DiagnosticCxBuilder<'_, '_, '_, 'tcx>,
+        mut f: impl FnMut(
+            &mut Stack,
+            &mut DiagnosticCx<'_, '_, '_, '_, 'tcx>,
+            &mut FxHashSet<SbTag>,
+        ) -> InterpResult<'tcx>,
+    ) -> InterpResult<'tcx> {
+        self.modified_since_last_gc = true;
+        for (offset, stack) in self.stacks.iter_mut(range.start, range.size) {
+            let mut dcx = dcx_builder.build(&mut self.history, offset);
+            f(stack, &mut dcx, &mut self.exposed_tags)?;
+            dcx_builder = dcx.unbuild();
+        }
+        Ok(())
+    }
+}
+
+/// Glue code to connect with Miri Machine Hooks
+impl Stacks {
+    pub fn new_allocation(
+        id: AllocId,
+        size: Size,
+        state: &GlobalState,
+        kind: MemoryKind<MiriMemoryKind>,
+        mut current_span: CurrentSpan<'_, '_, '_>,
+    ) -> Self {
+        let mut extra = state.borrow_mut();
+        let (base_tag, perm) = match kind {
+            // New unique borrow. This tag is not accessible by the program,
+            // so it will only ever be used when using the local directly (i.e.,
+            // not through a pointer). That is, whenever we directly write to a local, this will pop
+            // everything else off the stack, invalidating all previous pointers,
+            // and in particular, *all* raw pointers.
+            MemoryKind::Stack =>
+                (extra.base_ptr_tag(id, current_span.machine()), Permission::Unique),
+            // Everything else is shared by default.
+            _ => (extra.base_ptr_tag(id, current_span.machine()), Permission::SharedReadWrite),
+        };
+        Stacks::new(size, perm, base_tag, id, &mut current_span)
+    }
+
+    #[inline(always)]
+    pub fn before_memory_read<'tcx, 'mir, 'ecx>(
+        &mut self,
+        alloc_id: AllocId,
+        tag: ProvenanceExtra,
+        range: AllocRange,
+        state: &GlobalState,
+        mut current_span: CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+    ) -> InterpResult<'tcx>
+    where
+        'tcx: 'ecx,
+    {
+        trace!(
+            "read access with tag {:?}: {:?}, size {}",
+            tag,
+            Pointer::new(alloc_id, range.start),
+            range.size.bytes()
+        );
+        let dcx = DiagnosticCxBuilder::read(&mut current_span, threads, tag, range);
+        let mut state = state.borrow_mut();
+        self.for_each(range, dcx, |stack, dcx, exposed_tags| {
+            stack.access(AccessKind::Read, tag, &mut state, dcx, exposed_tags)
+        })
+    }
+
+    #[inline(always)]
+    pub fn before_memory_write<'tcx, 'mir, 'ecx>(
+        &mut self,
+        alloc_id: AllocId,
+        tag: ProvenanceExtra,
+        range: AllocRange,
+        state: &GlobalState,
+        mut current_span: CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+    ) -> InterpResult<'tcx> {
+        trace!(
+            "write access with tag {:?}: {:?}, size {}",
+            tag,
+            Pointer::new(alloc_id, range.start),
+            range.size.bytes()
+        );
+        let dcx = DiagnosticCxBuilder::write(&mut current_span, threads, tag, range);
+        let mut state = state.borrow_mut();
+        self.for_each(range, dcx, |stack, dcx, exposed_tags| {
+            stack.access(AccessKind::Write, tag, &mut state, dcx, exposed_tags)
+        })
+    }
+
+    #[inline(always)]
+    pub fn before_memory_deallocation<'tcx, 'mir, 'ecx>(
+        &mut self,
+        alloc_id: AllocId,
+        tag: ProvenanceExtra,
+        range: AllocRange,
+        state: &GlobalState,
+        mut current_span: CurrentSpan<'ecx, 'mir, 'tcx>,
+        threads: &'ecx ThreadManager<'mir, 'tcx>,
+    ) -> InterpResult<'tcx> {
+        trace!("deallocation with tag {:?}: {:?}, size {}", tag, alloc_id, range.size.bytes());
+        let dcx = DiagnosticCxBuilder::dealloc(&mut current_span, threads, tag);
+        let state = state.borrow();
+        self.for_each(range, dcx, |stack, dcx, exposed_tags| {
+            stack.dealloc(tag, &state, dcx, exposed_tags)
+        })?;
+        Ok(())
+    }
+}
+
+/// Retagging/reborrowing.  There is some policy in here, such as which permissions
+/// to grant for which references, and when to add protectors.
+impl<'mir: 'ecx, 'tcx: 'mir, 'ecx> EvalContextPrivExt<'mir, 'tcx, 'ecx>
+    for crate::MiriInterpCx<'mir, 'tcx>
+{
+}
+trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    /// Returns the `AllocId` the reborrow was done in, if some actual borrow stack manipulation
+    /// happened.
+    fn reborrow(
+        &mut self,
+        place: &MPlaceTy<'tcx, Provenance>,
+        size: Size,
+        kind: RefKind,
+        retag_cause: RetagCause, // What caused this retag, for diagnostics only
+        new_tag: SbTag,
+        protect: bool,
+    ) -> InterpResult<'tcx, Option<AllocId>> {
+        let this = self.eval_context_mut();
+
+        // It is crucial that this gets called on all code paths, to ensure we track tag creation.
+        let log_creation = |this: &MiriInterpCx<'mir, 'tcx>,
+                            loc: Option<(AllocId, Size, ProvenanceExtra)>| // alloc_id, base_offset, orig_tag
+         -> InterpResult<'tcx> {
+            let global = this.machine.stacked_borrows.as_ref().unwrap().borrow();
+            if global.tracked_pointer_tags.contains(&new_tag) {
+                this.emit_diagnostic(NonHaltingDiagnostic::CreatedPointerTag(
+                    new_tag.0,
+                    loc.map(|(alloc_id, base_offset, _)| (alloc_id, alloc_range(base_offset, size))),
+                ));
+            }
+            drop(global); // don't hold that reference any longer than we have to
+
+            let Some((alloc_id, base_offset, orig_tag)) = loc else {
+                return Ok(())
+            };
+
+            let (_size, _align, alloc_kind) = this.get_alloc_info(alloc_id);
+            match alloc_kind {
+                AllocKind::LiveData => {
+                    let current_span = &mut this.machine.current_span();
+                    // This should have alloc_extra data, but `get_alloc_extra` can still fail
+                    // if converting this alloc_id from a global to a local one
+                    // uncovers a non-supported `extern static`.
+                    let extra = this.get_alloc_extra(alloc_id)?;
+                    let mut stacked_borrows = extra
+                        .stacked_borrows
+                        .as_ref()
+                        .expect("we should have Stacked Borrows data")
+                        .borrow_mut();
+                    let threads = &this.machine.threads;
+                    // Note that we create a *second* `DiagnosticCxBuilder` below for the actual retag.
+                    // FIXME: can this be done cleaner?
+                    let dcx = DiagnosticCxBuilder::retag(
+                        current_span,
+                        threads,
+                        retag_cause,
+                        new_tag,
+                        orig_tag,
+                        alloc_range(base_offset, size),
+                    );
+                    let mut dcx = dcx.build(&mut stacked_borrows.history, base_offset);
+                    dcx.log_creation();
+                    if protect {
+                        dcx.log_protector();
+                    }
+                }
+                AllocKind::Function | AllocKind::VTable | AllocKind::Dead => {
+                    // No stacked borrows on these allocations.
+                }
+            }
+            Ok(())
+        };
+
+        if size == Size::ZERO {
+            trace!(
+                "reborrow of size 0: {} reference {:?} derived from {:?} (pointee {})",
+                kind,
+                new_tag,
+                place.ptr,
+                place.layout.ty,
+            );
+            // Don't update any stacks for a zero-sized access; borrow stacks are per-byte and this
+            // touches no bytes so there is no stack to put this tag in.
+            // However, if the pointer for this operation points at a real allocation we still
+            // record where it was created so that we can issue a helpful diagnostic if there is an
+            // attempt to use it for a non-zero-sized access.
+            // Dangling slices are a common case here; it's valid to get their length but with raw
+            // pointer tagging for example all calls to get_unchecked on them are invalid.
+            if let Ok((alloc_id, base_offset, orig_tag)) = this.ptr_try_get_alloc_id(place.ptr) {
+                log_creation(this, Some((alloc_id, base_offset, orig_tag)))?;
+                return Ok(Some(alloc_id));
+            }
+            // This pointer doesn't come with an AllocId. :shrug:
+            log_creation(this, None)?;
+            return Ok(None);
+        }
+
+        let (alloc_id, base_offset, orig_tag) = this.ptr_get_alloc_id(place.ptr)?;
+        log_creation(this, Some((alloc_id, base_offset, orig_tag)))?;
+
+        // Ensure we bail out if the pointer goes out-of-bounds (see miri#1050).
+        let (alloc_size, _) = this.get_live_alloc_size_and_align(alloc_id)?;
+        if base_offset + size > alloc_size {
+            throw_ub!(PointerOutOfBounds {
+                alloc_id,
+                alloc_size,
+                ptr_offset: this.machine_usize_to_isize(base_offset.bytes()),
+                ptr_size: size,
+                msg: CheckInAllocMsg::InboundsTest
+            });
+        }
+
+        trace!(
+            "reborrow: {} reference {:?} derived from {:?} (pointee {}): {:?}, size {}",
+            kind,
+            new_tag,
+            orig_tag,
+            place.layout.ty,
+            Pointer::new(alloc_id, base_offset),
+            size.bytes()
+        );
+
+        if protect {
+            // See comment in `Stack::item_popped` for why we store the tag twice.
+            this.frame_mut().extra.stacked_borrows.as_mut().unwrap().protected_tags.push(new_tag);
+            this.machine.stacked_borrows.as_mut().unwrap().get_mut().protected_tags.insert(new_tag);
+        }
+
+        // Update the stacks.
+        // Make sure that raw pointers and mutable shared references are reborrowed "weak":
+        // There could be existing unique pointers reborrowed from them that should remain valid!
+        let perm = match kind {
+            RefKind::Unique { two_phase: false }
+                if place.layout.ty.is_unpin(this.tcx.at(DUMMY_SP), this.param_env()) =>
+            {
+                // Only if the type is unpin do we actually enforce uniqueness
+                Permission::Unique
+            }
+            RefKind::Unique { .. } => {
+                // Two-phase references and !Unpin references are treated as SharedReadWrite
+                Permission::SharedReadWrite
+            }
+            RefKind::Raw { mutable: true } => Permission::SharedReadWrite,
+            RefKind::Shared | RefKind::Raw { mutable: false } => {
+                // Shared references and *const are a whole different kind of game, the
+                // permission is not uniform across the entire range!
+                // We need a frozen-sensitive reborrow.
+                // We have to use shared references to alloc/memory_extra here since
+                // `visit_freeze_sensitive` needs to access the global state.
+                let extra = this.get_alloc_extra(alloc_id)?;
+                let mut stacked_borrows = extra
+                    .stacked_borrows
+                    .as_ref()
+                    .expect("we should have Stacked Borrows data")
+                    .borrow_mut();
+                // FIXME: can't share this with the current_span inside log_creation
+                let mut current_span = this.machine.current_span();
+                this.visit_freeze_sensitive(place, size, |mut range, frozen| {
+                    // Adjust range.
+                    range.start += base_offset;
+                    // We are only ever `SharedReadOnly` inside the frozen bits.
+                    let perm = if frozen {
+                        Permission::SharedReadOnly
+                    } else {
+                        Permission::SharedReadWrite
+                    };
+                    let protected = if frozen {
+                        protect
+                    } else {
+                        // We do not protect inside UnsafeCell.
+                        // This fixes https://github.com/rust-lang/rust/issues/55005.
+                        false
+                    };
+                    let item = Item::new(new_tag, perm, protected);
+                    let mut global = this.machine.stacked_borrows.as_ref().unwrap().borrow_mut();
+                    let dcx = DiagnosticCxBuilder::retag(
+                        &mut current_span, // FIXME avoid this `clone`
+                        &this.machine.threads,
+                        retag_cause,
+                        new_tag,
+                        orig_tag,
+                        alloc_range(base_offset, size),
+                    );
+                    stacked_borrows.for_each(range, dcx, |stack, dcx, exposed_tags| {
+                        stack.grant(orig_tag, item, &mut global, dcx, exposed_tags)
+                    })
+                })?;
+                return Ok(Some(alloc_id));
+            }
+        };
+
+        // Here we can avoid `borrow()` calls because we have mutable references.
+        // Note that this asserts that the allocation is mutable -- but since we are creating a
+        // mutable pointer, that seems reasonable.
+        let (alloc_extra, machine) = this.get_alloc_extra_mut(alloc_id)?;
+        let mut stacked_borrows = alloc_extra
+            .stacked_borrows
+            .as_mut()
+            .expect("we should have Stacked Borrows data")
+            .borrow_mut();
+        let item = Item::new(new_tag, perm, protect);
+        let range = alloc_range(base_offset, size);
+        let mut global = machine.stacked_borrows.as_ref().unwrap().borrow_mut();
+        // FIXME: can't share this with the current_span inside log_creation
+        let current_span = &mut machine.current_span();
+        let dcx = DiagnosticCxBuilder::retag(
+            current_span,
+            &machine.threads,
+            retag_cause,
+            new_tag,
+            orig_tag,
+            alloc_range(base_offset, size),
+        );
+        stacked_borrows.for_each(range, dcx, |stack, dcx, exposed_tags| {
+            stack.grant(orig_tag, item, &mut global, dcx, exposed_tags)
+        })?;
+
+        Ok(Some(alloc_id))
+    }
+
+    /// Retags an indidual pointer, returning the retagged version.
+    /// `mutbl` can be `None` to make this a raw pointer.
+    fn retag_reference(
+        &mut self,
+        val: &ImmTy<'tcx, Provenance>,
+        kind: RefKind,
+        retag_cause: RetagCause, // What caused this retag, for diagnostics only
+        protect: bool,
+    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
+        let this = self.eval_context_mut();
+        // We want a place for where the ptr *points to*, so we get one.
+        let place = this.ref_to_mplace(val)?;
+        let size = this.size_and_align_of_mplace(&place)?.map(|(size, _)| size);
+        // FIXME: If we cannot determine the size (because the unsized tail is an `extern type`),
+        // bail out -- we cannot reasonably figure out which memory range to reborrow.
+        // See https://github.com/rust-lang/unsafe-code-guidelines/issues/276.
+        let size = match size {
+            Some(size) => size,
+            None => return Ok(val.clone()),
+        };
+
+        // Compute new borrow.
+        let new_tag = this.machine.stacked_borrows.as_mut().unwrap().get_mut().new_ptr();
+
+        // Reborrow.
+        let alloc_id = this.reborrow(&place, size, kind, retag_cause, new_tag, protect)?;
+
+        // Adjust pointer.
+        let new_place = place.map_provenance(|p| {
+            p.map(|prov| {
+                match alloc_id {
+                    Some(alloc_id) => {
+                        // If `reborrow` could figure out the AllocId of this ptr, hard-code it into the new one.
+                        // Even if we started out with a wildcard, this newly retagged pointer is tied to that allocation.
+                        Provenance::Concrete { alloc_id, sb: new_tag }
+                    }
+                    None => {
+                        // Looks like this has to stay a wildcard pointer.
+                        assert!(matches!(prov, Provenance::Wildcard));
+                        Provenance::Wildcard
+                    }
+                }
+            })
+        });
+
+        // Return new pointer.
+        Ok(ImmTy::from_immediate(new_place.to_ref(this), val.layout))
+    }
+}
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
+    fn retag(&mut self, kind: RetagKind, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let retag_fields = this.machine.stacked_borrows.as_mut().unwrap().get_mut().retag_fields;
+        let retag_cause = match kind {
+            RetagKind::TwoPhase { .. } => RetagCause::TwoPhase,
+            RetagKind::FnEntry => RetagCause::FnEntry,
+            RetagKind::Raw | RetagKind::Default => RetagCause::Normal,
+        };
+        let mut visitor = RetagVisitor { ecx: this, kind, retag_cause, retag_fields };
+        return visitor.visit_value(place);
+
+        // Determine mutability and whether to add a protector.
+        // Cannot use `builtin_deref` because that reports *immutable* for `Box`,
+        // making it useless.
+        fn qualify(ty: Ty<'_>, kind: RetagKind) -> Option<(RefKind, bool)> {
+            match ty.kind() {
+                // References are simple.
+                ty::Ref(_, _, Mutability::Mut) =>
+                    Some((
+                        RefKind::Unique { two_phase: kind == RetagKind::TwoPhase },
+                        kind == RetagKind::FnEntry,
+                    )),
+                ty::Ref(_, _, Mutability::Not) =>
+                    Some((RefKind::Shared, kind == RetagKind::FnEntry)),
+                // Raw pointers need to be enabled.
+                ty::RawPtr(tym) if kind == RetagKind::Raw =>
+                    Some((RefKind::Raw { mutable: tym.mutbl == Mutability::Mut }, false)),
+                // Boxes are handled separately due to that allocator situation,
+                // see the visitor below.
+                _ => None,
+            }
+        }
+
+        // The actual visitor.
+        struct RetagVisitor<'ecx, 'mir, 'tcx> {
+            ecx: &'ecx mut MiriInterpCx<'mir, 'tcx>,
+            kind: RetagKind,
+            retag_cause: RetagCause,
+            retag_fields: bool,
+        }
+        impl<'ecx, 'mir, 'tcx> RetagVisitor<'ecx, 'mir, 'tcx> {
+            #[inline(always)] // yes this helps in our benchmarks
+            fn retag_place(
+                &mut self,
+                place: &PlaceTy<'tcx, Provenance>,
+                ref_kind: RefKind,
+                retag_cause: RetagCause,
+                protector: bool,
+            ) -> InterpResult<'tcx> {
+                let val = self.ecx.read_immediate(&self.ecx.place_to_op(place)?)?;
+                let val = self.ecx.retag_reference(&val, ref_kind, retag_cause, protector)?;
+                self.ecx.write_immediate(*val, place)?;
+                Ok(())
+            }
+        }
+        impl<'ecx, 'mir, 'tcx> MutValueVisitor<'mir, 'tcx, MiriMachine<'mir, 'tcx>>
+            for RetagVisitor<'ecx, 'mir, 'tcx>
+        {
+            type V = PlaceTy<'tcx, Provenance>;
+
+            #[inline(always)]
+            fn ecx(&mut self) -> &mut MiriInterpCx<'mir, 'tcx> {
+                self.ecx
+            }
+
+            fn visit_box(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+                // Boxes do not get a protector: protectors reflect that references outlive the call
+                // they were passed in to; that's just not the case for boxes.
+                self.retag_place(
+                    place,
+                    RefKind::Unique { two_phase: false },
+                    self.retag_cause,
+                    /*protector*/ false,
+                )
+            }
+
+            fn visit_value(&mut self, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+                // If this place is smaller than a pointer, we know that it can't contain any
+                // pointers we need to retag, so we can stop recursion early.
+                // This optimization is crucial for ZSTs, because they can contain way more fields
+                // than we can ever visit.
+                if !place.layout.is_unsized() && place.layout.size < self.ecx.pointer_size() {
+                    return Ok(());
+                }
+
+                if let Some((ref_kind, protector)) = qualify(place.layout.ty, self.kind) {
+                    self.retag_place(place, ref_kind, self.retag_cause, protector)?;
+                } else if matches!(place.layout.ty.kind(), ty::RawPtr(..)) {
+                    // Wide raw pointers *do* have fields and their types are strange.
+                    // vtables have a type like `&[*const (); 3]` or so!
+                    // Do *not* recurse into them.
+                    // (No need to worry about wide references, those always "qualify". And Boxes
+                    // are handles specially by the visitor anyway.)
+                } else if self.retag_fields
+                    || place.layout.ty.ty_adt_def().is_some_and(|adt| adt.is_box())
+                {
+                    // Recurse deeper. Need to always recurse for `Box` to even hit `visit_box`.
+                    // (Yes this means we technically also recursively retag the allocator itself
+                    // even if field retagging is not enabled. *shrug*)
+                    self.walk_value(place)?;
+                }
+                Ok(())
+            }
+        }
+    }
+
+    /// After a stack frame got pushed, retag the return place so that we are sure
+    /// it does not alias with anything.
+    ///
+    /// This is a HACK because there is nothing in MIR that would make the retag
+    /// explicit. Also see <https://github.com/rust-lang/rust/issues/71117>.
+    fn retag_return_place(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        let return_place = &this.frame().return_place;
+        if return_place.layout.is_zst() {
+            // There may not be any memory here, nothing to do.
+            return Ok(());
+        }
+        // We need this to be in-memory to use tagged pointers.
+        let return_place = this.force_allocation(&return_place.clone())?;
+
+        // We have to turn the place into a pointer to use the existing code.
+        // (The pointer type does not matter, so we use a raw pointer.)
+        let ptr_layout = this.layout_of(this.tcx.mk_mut_ptr(return_place.layout.ty))?;
+        let val = ImmTy::from_immediate(return_place.to_ref(this), ptr_layout);
+        // Reborrow it.
+        let val = this.retag_reference(
+            &val,
+            RefKind::Unique { two_phase: false },
+            RetagCause::FnReturn,
+            /*protector*/ true,
+        )?;
+        // And use reborrowed pointer for return place.
+        let return_place = this.ref_to_mplace(&val)?;
+        this.frame_mut().return_place = return_place.into();
+
+        Ok(())
+    }
+
+    /// Mark the given tag as exposed. It was found on a pointer with the given AllocId.
+    fn expose_tag(&mut self, alloc_id: AllocId, tag: SbTag) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+
+        // Function pointers and dead objects don't have an alloc_extra so we ignore them.
+        // This is okay because accessing them is UB anyway, no need for any Stacked Borrows checks.
+        // NOT using `get_alloc_extra_mut` since this might be a read-only allocation!
+        let (_size, _align, kind) = this.get_alloc_info(alloc_id);
+        match kind {
+            AllocKind::LiveData => {
+                // This should have alloc_extra data, but `get_alloc_extra` can still fail
+                // if converting this alloc_id from a global to a local one
+                // uncovers a non-supported `extern static`.
+                let alloc_extra = this.get_alloc_extra(alloc_id)?;
+                trace!("Stacked Borrows tag {tag:?} exposed in {alloc_id:?}");
+                alloc_extra.stacked_borrows.as_ref().unwrap().borrow_mut().exposed_tags.insert(tag);
+            }
+            AllocKind::Function | AllocKind::VTable | AllocKind::Dead => {
+                // No stacked borrows on these allocations.
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/stacked_borrows/stack.rs b/src/tools/miri/src/stacked_borrows/stack.rs
new file mode 100644
index 000000000000..494ea08b56e4
--- /dev/null
+++ b/src/tools/miri/src/stacked_borrows/stack.rs
@@ -0,0 +1,462 @@
+#[cfg(feature = "stack-cache")]
+use std::ops::Range;
+
+use rustc_data_structures::fx::FxHashSet;
+
+use crate::stacked_borrows::{AccessKind, Item, Permission, SbTag};
+use crate::ProvenanceExtra;
+
+/// Exactly what cache size we should use is a difficult tradeoff. There will always be some
+/// workload which has a `SbTag` working set which exceeds the size of the cache, and ends up
+/// falling back to linear searches of the borrow stack very often.
+/// The cost of making this value too large is that the loop in `Stack::insert` which ensures the
+/// entries in the cache stay correct after an insert becomes expensive.
+#[cfg(feature = "stack-cache")]
+const CACHE_LEN: usize = 32;
+
+/// Extra per-location state.
+#[derive(Clone, Debug)]
+pub struct Stack {
+    /// Used *mostly* as a stack; never empty.
+    /// Invariants:
+    /// * Above a `SharedReadOnly` there can only be more `SharedReadOnly`.
+    /// * Except for `Untagged`, no tag occurs in the stack more than once.
+    borrows: Vec<Item>,
+    /// If this is `Some(id)`, then the actual current stack is unknown. This can happen when
+    /// wildcard pointers are used to access this location. What we do know is that `borrows` are at
+    /// the top of the stack, and below it are arbitrarily many items whose `tag` is strictly less
+    /// than `id`.
+    /// When the bottom is unknown, `borrows` always has a `SharedReadOnly` or `Unique` at the bottom;
+    /// we never have the unknown-to-known boundary in an SRW group.
+    unknown_bottom: Option<SbTag>,
+
+    /// A small LRU cache of searches of the borrow stack.
+    #[cfg(feature = "stack-cache")]
+    cache: StackCache,
+    /// On a read, we need to disable all `Unique` above the granting item. We can avoid most of
+    /// this scan by keeping track of the region of the borrow stack that may contain `Unique`s.
+    #[cfg(feature = "stack-cache")]
+    unique_range: Range<usize>,
+}
+
+impl Stack {
+    pub fn retain(&mut self, tags: &FxHashSet<SbTag>) {
+        let mut first_removed = None;
+
+        let mut read_idx = 1;
+        let mut write_idx = 1;
+        while read_idx < self.borrows.len() {
+            let left = self.borrows[read_idx - 1];
+            let this = self.borrows[read_idx];
+            let should_keep = match this.perm() {
+                // SharedReadWrite is the simplest case, if it's unreachable we can just remove it.
+                Permission::SharedReadWrite => tags.contains(&this.tag()),
+                // Only retain a Disabled tag if it is terminating a SharedReadWrite block.
+                Permission::Disabled => left.perm() == Permission::SharedReadWrite,
+                // Unique and SharedReadOnly can terminate a SharedReadWrite block, so only remove
+                // them if they are both unreachable and not directly after a SharedReadWrite.
+                Permission::Unique | Permission::SharedReadOnly =>
+                    left.perm() == Permission::SharedReadWrite || tags.contains(&this.tag()),
+            };
+
+            if should_keep {
+                if read_idx != write_idx {
+                    self.borrows[write_idx] = self.borrows[read_idx];
+                }
+                write_idx += 1;
+            } else if first_removed.is_none() {
+                first_removed = Some(read_idx);
+            }
+
+            read_idx += 1;
+        }
+        self.borrows.truncate(write_idx);
+
+        #[cfg(not(feature = "stack-cache"))]
+        drop(first_removed); // This is only needed for the stack-cache
+
+        #[cfg(feature = "stack-cache")]
+        if let Some(first_removed) = first_removed {
+            // Either end of unique_range may have shifted, all we really know is that we can't
+            // have introduced a new Unique.
+            if !self.unique_range.is_empty() {
+                self.unique_range = 0..self.len();
+            }
+
+            // Replace any Items which have been collected with the base item, a known-good value.
+            for i in 0..CACHE_LEN {
+                if self.cache.idx[i] >= first_removed {
+                    self.cache.items[i] = self.borrows[0];
+                    self.cache.idx[i] = 0;
+                }
+            }
+        }
+    }
+}
+
+/// A very small cache of searches of a borrow stack, mapping `Item`s to their position in said stack.
+///
+/// It may seem like maintaining this cache is a waste for small stacks, but
+/// (a) iterating over small fixed-size arrays is super fast, and (b) empirically this helps *a lot*,
+/// probably because runtime is dominated by large stacks.
+#[cfg(feature = "stack-cache")]
+#[derive(Clone, Debug)]
+struct StackCache {
+    items: [Item; CACHE_LEN], // Hot in find_granting
+    idx: [usize; CACHE_LEN],  // Hot in grant
+}
+
+#[cfg(feature = "stack-cache")]
+impl StackCache {
+    /// When a tag is used, we call this function to add or refresh it in the cache.
+    ///
+    /// We use the position in the cache to represent how recently a tag was used; the first position
+    /// is the most recently used tag. So an add shifts every element towards the end, and inserts
+    /// the new element at the start. We lose the last element.
+    /// This strategy is effective at keeping the most-accessed items in the cache, but it costs a
+    /// linear shift across the entire cache when we add a new tag.
+    fn add(&mut self, idx: usize, item: Item) {
+        self.items.copy_within(0..CACHE_LEN - 1, 1);
+        self.items[0] = item;
+        self.idx.copy_within(0..CACHE_LEN - 1, 1);
+        self.idx[0] = idx;
+    }
+}
+
+impl PartialEq for Stack {
+    fn eq(&self, other: &Self) -> bool {
+        // All the semantics of Stack are in self.borrows, everything else is caching
+        self.borrows == other.borrows
+    }
+}
+
+impl Eq for Stack {}
+
+impl<'tcx> Stack {
+    /// Panics if any of the caching mechanisms have broken,
+    /// - The StackCache indices don't refer to the parallel items,
+    /// - There are no Unique items outside of first_unique..last_unique
+    #[cfg(all(feature = "stack-cache", debug_assertions))]
+    fn verify_cache_consistency(&self) {
+        // Only a full cache needs to be valid. Also see the comments in find_granting_cache
+        // and set_unknown_bottom.
+        if self.borrows.len() >= CACHE_LEN {
+            for (tag, stack_idx) in self.cache.items.iter().zip(self.cache.idx.iter()) {
+                assert_eq!(self.borrows[*stack_idx], *tag);
+            }
+        }
+
+        // Check that all Unique items fall within unique_range.
+        for (idx, item) in self.borrows.iter().enumerate() {
+            if item.perm() == Permission::Unique {
+                assert!(
+                    self.unique_range.contains(&idx),
+                    "{:?} {:?}",
+                    self.unique_range,
+                    self.borrows
+                );
+            }
+        }
+
+        // Check that the unique_range is a valid index into the borrow stack.
+        // This asserts that the unique_range's start <= end.
+        let _uniques = &self.borrows[self.unique_range.clone()];
+
+        // We cannot assert that the unique range is precise.
+        // Both ends may shift around when `Stack::retain` is called. Additionally,
+        // when we pop items within the unique range, setting the end of the range precisely
+        // requires doing a linear search of the borrow stack, which is exactly the kind of
+        // operation that all this caching exists to avoid.
+    }
+
+    /// Find the item granting the given kind of access to the given tag, and return where
+    /// it is on the stack. For wildcard tags, the given index is approximate, but if *no*
+    /// index is given it means the match was *not* in the known part of the stack.
+    /// `Ok(None)` indicates it matched the "unknown" part of the stack.
+    /// `Err` indicates it was not found.
+    pub(super) fn find_granting(
+        &mut self,
+        access: AccessKind,
+        tag: ProvenanceExtra,
+        exposed_tags: &FxHashSet<SbTag>,
+    ) -> Result<Option<usize>, ()> {
+        #[cfg(all(feature = "stack-cache", debug_assertions))]
+        self.verify_cache_consistency();
+
+        let ProvenanceExtra::Concrete(tag) = tag else {
+            // Handle the wildcard case.
+            // Go search the stack for an exposed tag.
+            if let Some(idx) =
+                self.borrows
+                    .iter()
+                    .enumerate() // we also need to know *where* in the stack
+                    .rev() // search top-to-bottom
+                    .find_map(|(idx, item)| {
+                        // If the item fits and *might* be this wildcard, use it.
+                        if item.perm().grants(access) && exposed_tags.contains(&item.tag()) {
+                            Some(idx)
+                        } else {
+                            None
+                        }
+                    })
+            {
+                return Ok(Some(idx));
+            }
+            // If we couldn't find it in the stack, check the unknown bottom.
+            return if self.unknown_bottom.is_some() { Ok(None) } else { Err(()) };
+        };
+
+        if let Some(idx) = self.find_granting_tagged(access, tag) {
+            return Ok(Some(idx));
+        }
+
+        // Couldn't find it in the stack; but if there is an unknown bottom it might be there.
+        let found = self.unknown_bottom.is_some_and(|&unknown_limit| {
+            tag.0 < unknown_limit.0 // unknown_limit is an upper bound for what can be in the unknown bottom.
+        });
+        if found { Ok(None) } else { Err(()) }
+    }
+
+    fn find_granting_tagged(&mut self, access: AccessKind, tag: SbTag) -> Option<usize> {
+        #[cfg(feature = "stack-cache")]
+        if let Some(idx) = self.find_granting_cache(access, tag) {
+            return Some(idx);
+        }
+
+        // If we didn't find the tag in the cache, fall back to a linear search of the
+        // whole stack, and add the tag to the cache.
+        for (stack_idx, item) in self.borrows.iter().enumerate().rev() {
+            if tag == item.tag() && item.perm().grants(access) {
+                #[cfg(feature = "stack-cache")]
+                self.cache.add(stack_idx, *item);
+                return Some(stack_idx);
+            }
+        }
+        None
+    }
+
+    #[cfg(feature = "stack-cache")]
+    fn find_granting_cache(&mut self, access: AccessKind, tag: SbTag) -> Option<usize> {
+        // This looks like a common-sense optimization; we're going to do a linear search of the
+        // cache or the borrow stack to scan the shorter of the two. This optimization is miniscule
+        // and this check actually ensures we do not access an invalid cache.
+        // When a stack is created and when items are removed from the top of the borrow stack, we
+        // need some valid value to populate the cache. In both cases, we try to use the bottom
+        // item. But when the stack is cleared in `set_unknown_bottom` there is nothing we could
+        // place in the cache that is correct. But due to the way we populate the cache in
+        // `StackCache::add`, we know that when the borrow stack has grown larger than the cache,
+        // every slot in the cache is valid.
+        if self.borrows.len() <= CACHE_LEN {
+            return None;
+        }
+        // Search the cache for the tag we're looking up
+        let cache_idx = self.cache.items.iter().position(|t| t.tag() == tag)?;
+        let stack_idx = self.cache.idx[cache_idx];
+        // If we found the tag, look up its position in the stack to see if it grants
+        // the required permission
+        if self.cache.items[cache_idx].perm().grants(access) {
+            // If it does, and it's not already in the most-recently-used position, re-insert it at
+            // the most-recently-used position. This technically reduces the efficiency of the
+            // cache by duplicating elements, but current benchmarks do not seem to benefit from
+            // avoiding this duplication.
+            // But if the tag is in position 1, avoiding the duplicating add is trivial.
+            // If it does, and it's not already in the most-recently-used position, move it there.
+            // Except if the tag is in position 1, this is equivalent to just a swap, so do that.
+            if cache_idx == 1 {
+                self.cache.items.swap(0, 1);
+                self.cache.idx.swap(0, 1);
+            } else if cache_idx > 1 {
+                self.cache.add(stack_idx, self.cache.items[cache_idx]);
+            }
+            Some(stack_idx)
+        } else {
+            // Tag is in the cache, but it doesn't grant the required permission
+            None
+        }
+    }
+
+    pub fn insert(&mut self, new_idx: usize, new: Item) {
+        self.borrows.insert(new_idx, new);
+
+        #[cfg(feature = "stack-cache")]
+        self.insert_cache(new_idx, new);
+    }
+
+    #[cfg(feature = "stack-cache")]
+    fn insert_cache(&mut self, new_idx: usize, new: Item) {
+        // Adjust the possibly-unique range if an insert occurs before or within it
+        if self.unique_range.start >= new_idx {
+            self.unique_range.start += 1;
+        }
+        if self.unique_range.end >= new_idx {
+            self.unique_range.end += 1;
+        }
+        if new.perm() == Permission::Unique {
+            // If this is the only Unique, set the range to contain just the new item.
+            if self.unique_range.is_empty() {
+                self.unique_range = new_idx..new_idx + 1;
+            } else {
+                // We already have other Unique items, expand the range to include the new item
+                self.unique_range.start = self.unique_range.start.min(new_idx);
+                self.unique_range.end = self.unique_range.end.max(new_idx + 1);
+            }
+        }
+
+        // The above insert changes the meaning of every index in the cache >= new_idx, so now
+        // we need to find every one of those indexes and increment it.
+        // But if the insert is at the end (equivalent to a push), we can skip this step because
+        // it didn't change the position of any other items.
+        if new_idx != self.borrows.len() - 1 {
+            for idx in &mut self.cache.idx {
+                if *idx >= new_idx {
+                    *idx += 1;
+                }
+            }
+        }
+
+        // This primes the cache for the next access, which is almost always the just-added tag.
+        self.cache.add(new_idx, new);
+
+        #[cfg(debug_assertions)]
+        self.verify_cache_consistency();
+    }
+
+    /// Construct a new `Stack` using the passed `Item` as the base tag.
+    pub fn new(item: Item) -> Self {
+        Stack {
+            borrows: vec![item],
+            unknown_bottom: None,
+            #[cfg(feature = "stack-cache")]
+            cache: StackCache { idx: [0; CACHE_LEN], items: [item; CACHE_LEN] },
+            #[cfg(feature = "stack-cache")]
+            unique_range: if item.perm() == Permission::Unique { 0..1 } else { 0..0 },
+        }
+    }
+
+    pub fn get(&self, idx: usize) -> Option<Item> {
+        self.borrows.get(idx).cloned()
+    }
+
+    #[allow(clippy::len_without_is_empty)] // Stacks are never empty
+    pub fn len(&self) -> usize {
+        self.borrows.len()
+    }
+
+    pub fn unknown_bottom(&self) -> Option<SbTag> {
+        self.unknown_bottom
+    }
+
+    pub fn set_unknown_bottom(&mut self, tag: SbTag) {
+        // We clear the borrow stack but the lookup cache doesn't support clearing per se. Instead,
+        // there is a check explained in `find_granting_cache` which protects against accessing the
+        // cache when it has been cleared and not yet refilled.
+        self.borrows.clear();
+        self.unknown_bottom = Some(tag);
+        #[cfg(feature = "stack-cache")]
+        {
+            self.unique_range = 0..0;
+        }
+    }
+
+    /// Find all `Unique` elements in this borrow stack above `granting_idx`, pass a copy of them
+    /// to the `visitor`, then set their `Permission` to `Disabled`.
+    pub fn disable_uniques_starting_at<V: FnMut(Item) -> crate::InterpResult<'tcx>>(
+        &mut self,
+        disable_start: usize,
+        mut visitor: V,
+    ) -> crate::InterpResult<'tcx> {
+        #[cfg(feature = "stack-cache")]
+        let unique_range = self.unique_range.clone();
+        #[cfg(not(feature = "stack-cache"))]
+        let unique_range = 0..self.len();
+
+        if disable_start <= unique_range.end {
+            let lower = unique_range.start.max(disable_start);
+            let upper = unique_range.end;
+            for item in &mut self.borrows[lower..upper] {
+                if item.perm() == Permission::Unique {
+                    log::trace!("access: disabling item {:?}", item);
+                    visitor(*item)?;
+                    item.set_permission(Permission::Disabled);
+                    // Also update all copies of this item in the cache.
+                    #[cfg(feature = "stack-cache")]
+                    for it in &mut self.cache.items {
+                        if it.tag() == item.tag() {
+                            it.set_permission(Permission::Disabled);
+                        }
+                    }
+                }
+            }
+        }
+
+        #[cfg(feature = "stack-cache")]
+        if disable_start <= self.unique_range.start {
+            // We disabled all Unique items
+            self.unique_range.start = 0;
+            self.unique_range.end = 0;
+        } else {
+            // Truncate the range to only include items up to the index that we started disabling
+            // at.
+            self.unique_range.end = self.unique_range.end.min(disable_start);
+        }
+
+        #[cfg(all(feature = "stack-cache", debug_assertions))]
+        self.verify_cache_consistency();
+
+        Ok(())
+    }
+
+    /// Produces an iterator which iterates over `range` in reverse, and when dropped removes that
+    /// range of `Item`s from this `Stack`.
+    pub fn pop_items_after<V: FnMut(Item) -> crate::InterpResult<'tcx>>(
+        &mut self,
+        start: usize,
+        mut visitor: V,
+    ) -> crate::InterpResult<'tcx> {
+        while self.borrows.len() > start {
+            let item = self.borrows.pop().unwrap();
+            visitor(item)?;
+        }
+
+        #[cfg(feature = "stack-cache")]
+        if !self.borrows.is_empty() {
+            // After we remove from the borrow stack, every aspect of our caching may be invalid, but it is
+            // also possible that the whole cache is still valid. So we call this method to repair what
+            // aspects of the cache are now invalid, instead of resetting the whole thing to a trivially
+            // valid default state.
+            let base_tag = self.borrows[0];
+            let mut removed = 0;
+            let mut cursor = 0;
+            // Remove invalid entries from the cache by rotating them to the end of the cache, then
+            // keep track of how many invalid elements there are and overwrite them with the base tag.
+            // The base tag here serves as a harmless default value.
+            for _ in 0..CACHE_LEN - 1 {
+                if self.cache.idx[cursor] >= start {
+                    self.cache.idx[cursor..CACHE_LEN - removed].rotate_left(1);
+                    self.cache.items[cursor..CACHE_LEN - removed].rotate_left(1);
+                    removed += 1;
+                } else {
+                    cursor += 1;
+                }
+            }
+            for i in CACHE_LEN - removed - 1..CACHE_LEN {
+                self.cache.idx[i] = 0;
+                self.cache.items[i] = base_tag;
+            }
+
+            if start <= self.unique_range.start {
+                // We removed all the Unique items
+                self.unique_range = 0..0;
+            } else {
+                // Ensure the range doesn't extend past the new top of the stack
+                self.unique_range.end = self.unique_range.end.min(start);
+            }
+        } else {
+            self.unique_range = 0..0;
+        }
+
+        #[cfg(all(feature = "stack-cache", debug_assertions))]
+        self.verify_cache_consistency();
+        Ok(())
+    }
+}
diff --git a/src/tools/miri/src/tag_gc.rs b/src/tools/miri/src/tag_gc.rs
new file mode 100644
index 000000000000..e20a86711478
--- /dev/null
+++ b/src/tools/miri/src/tag_gc.rs
@@ -0,0 +1,117 @@
+use crate::*;
+use rustc_data_structures::fx::FxHashSet;
+
+impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
+pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
+    fn garbage_collect_tags(&mut self) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        // No reason to do anything at all if stacked borrows is off.
+        if this.machine.stacked_borrows.is_none() {
+            return Ok(());
+        }
+
+        let mut tags = FxHashSet::default();
+
+        for thread in this.machine.threads.iter() {
+            if let Some(Scalar::Ptr(
+                Pointer { provenance: Provenance::Concrete { sb, .. }, .. },
+                _,
+            )) = thread.panic_payload
+            {
+                tags.insert(sb);
+            }
+        }
+
+        self.find_tags_in_tls(&mut tags);
+        self.find_tags_in_memory(&mut tags);
+        self.find_tags_in_locals(&mut tags)?;
+
+        self.remove_unreachable_tags(tags);
+
+        Ok(())
+    }
+
+    fn find_tags_in_tls(&mut self, tags: &mut FxHashSet<SbTag>) {
+        let this = self.eval_context_mut();
+        this.machine.tls.iter(|scalar| {
+            if let Scalar::Ptr(Pointer { provenance: Provenance::Concrete { sb, .. }, .. }, _) =
+                scalar
+            {
+                tags.insert(*sb);
+            }
+        });
+    }
+
+    fn find_tags_in_memory(&mut self, tags: &mut FxHashSet<SbTag>) {
+        let this = self.eval_context_mut();
+        this.memory.alloc_map().iter(|it| {
+            for (_id, (_kind, alloc)) in it {
+                for (_size, prov) in alloc.provenance().iter() {
+                    if let Provenance::Concrete { sb, .. } = prov {
+                        tags.insert(*sb);
+                    }
+                }
+            }
+        });
+    }
+
+    fn find_tags_in_locals(&mut self, tags: &mut FxHashSet<SbTag>) -> InterpResult<'tcx> {
+        let this = self.eval_context_mut();
+        for frame in this.machine.threads.all_stacks().flatten() {
+            // Handle the return place of each frame
+            if let Ok(return_place) = frame.return_place.try_as_mplace() {
+                if let Some(Provenance::Concrete { sb, .. }) = return_place.ptr.provenance {
+                    tags.insert(sb);
+                }
+            }
+
+            for local in frame.locals.iter() {
+                let LocalValue::Live(value) = local.value else {
+                continue;
+            };
+                match value {
+                    Operand::Immediate(Immediate::Scalar(Scalar::Ptr(ptr, _))) =>
+                        if let Provenance::Concrete { sb, .. } = ptr.provenance {
+                            tags.insert(sb);
+                        },
+                    Operand::Immediate(Immediate::ScalarPair(s1, s2)) => {
+                        if let Scalar::Ptr(ptr, _) = s1 {
+                            if let Provenance::Concrete { sb, .. } = ptr.provenance {
+                                tags.insert(sb);
+                            }
+                        }
+                        if let Scalar::Ptr(ptr, _) = s2 {
+                            if let Provenance::Concrete { sb, .. } = ptr.provenance {
+                                tags.insert(sb);
+                            }
+                        }
+                    }
+                    Operand::Indirect(MemPlace { ptr, .. }) => {
+                        if let Some(Provenance::Concrete { sb, .. }) = ptr.provenance {
+                            tags.insert(sb);
+                        }
+                    }
+                    Operand::Immediate(Immediate::Uninit)
+                    | Operand::Immediate(Immediate::Scalar(Scalar::Int(_))) => {}
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    fn remove_unreachable_tags(&mut self, tags: FxHashSet<SbTag>) {
+        let this = self.eval_context_mut();
+        this.memory.alloc_map().iter(|it| {
+            for (_id, (_kind, alloc)) in it {
+                alloc
+                    .extra
+                    .stacked_borrows
+                    .as_ref()
+                    .unwrap()
+                    .borrow_mut()
+                    .remove_unreachable_tags(&tags);
+            }
+        });
+    }
+}
diff --git a/src/tools/miri/test-cargo-miri/.gitignore b/src/tools/miri/test-cargo-miri/.gitignore
new file mode 100644
index 000000000000..af5854e0c3fd
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/.gitignore
@@ -0,0 +1,4 @@
+*.real
+custom-run
+custom-test
+config-cli
diff --git a/src/tools/miri/test-cargo-miri/Cargo.lock b/src/tools/miri/test-cargo-miri/Cargo.lock
new file mode 100644
index 000000000000..a297dd27dbc9
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/Cargo.lock
@@ -0,0 +1,135 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "autocfg"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
+[[package]]
+name = "byteorder"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fc10e8cc6b2580fda3f36eb6dc5316657f812a3df879a44a66fc9f0fdbc4855"
+
+[[package]]
+name = "byteorder"
+version = "1.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
+[[package]]
+name = "cargo-miri-test"
+version = "0.1.0"
+dependencies = [
+ "autocfg",
+ "byteorder 0.5.3",
+ "byteorder 1.4.3",
+ "cdylib",
+ "exported_symbol",
+ "issue_1567",
+ "issue_1691",
+ "issue_1705",
+ "issue_1760",
+ "issue_rust_86261",
+ "serde_derive",
+]
+
+[[package]]
+name = "cdylib"
+version = "0.1.0"
+dependencies = [
+ "byteorder 1.4.3",
+]
+
+[[package]]
+name = "exported_symbol"
+version = "0.1.0"
+dependencies = [
+ "exported_symbol_dep",
+]
+
+[[package]]
+name = "exported_symbol_dep"
+version = "0.1.0"
+
+[[package]]
+name = "issue_1567"
+version = "0.1.0"
+dependencies = [
+ "byteorder 1.4.3",
+]
+
+[[package]]
+name = "issue_1691"
+version = "0.1.0"
+
+[[package]]
+name = "issue_1705"
+version = "0.1.0"
+dependencies = [
+ "byteorder 1.4.3",
+]
+
+[[package]]
+name = "issue_1760"
+version = "0.1.0"
+
+[[package]]
+name = "issue_rust_86261"
+version = "0.1.0"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd96a1e8ed2596c337f8eae5f24924ec83f5ad5ab21ea8e455d3566c69fbcaf7"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3bcdf212e9776fbcb2d23ab029360416bb1706b1aea2d1a5ba002727cbcab804"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.137"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f26faba0c3959972377d3b2d306ee9f71faee9714294e41bb777f83f88578be"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "subcrate"
+version = "0.1.0"
+dependencies = [
+ "byteorder 1.4.3",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c50aef8a904de4c23c788f104b7dddc7d6f79c647c7c8ce4cc8f73eb0ca773dd"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
diff --git a/src/tools/miri/test-cargo-miri/Cargo.toml b/src/tools/miri/test-cargo-miri/Cargo.toml
new file mode 100644
index 000000000000..5d9e5d143b3b
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/Cargo.toml
@@ -0,0 +1,32 @@
+[workspace]
+members = ["subcrate", "issue-1567", "exported-symbol-dep"]
+
+[package]
+name = "cargo-miri-test"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[dependencies]
+byteorder = "1.0"
+cdylib = { path = "cdylib" }
+exported_symbol = { path = "exported-symbol" }
+issue_1567 = { path = "issue-1567" }
+issue_1691 = { path = "issue-1691" }
+issue_1705 = { path = "issue-1705" }
+issue_1760 = { path = "issue-1760" }
+issue_rust_86261 = { path = "issue-rust-86261" }
+
+[dev-dependencies]
+byteorder_2 = { package = "byteorder", version = "0.5" } # to test dev-dependencies behave as expected, with renaming
+serde_derive = "1.0" # not actually used, but exercises some unique code path (`--extern` .so file)
+
+[build-dependencies]
+autocfg = "1"
+
+[lib]
+test = false # test that this is respected (will show in the output)
+
+[[test]]
+name = "main"
+harness = false
diff --git a/src/tools/miri/test-cargo-miri/build.rs b/src/tools/miri/test-cargo-miri/build.rs
new file mode 100644
index 000000000000..6c1f4d80d339
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/build.rs
@@ -0,0 +1,40 @@
+use std::env;
+
+#[cfg(miri)]
+compile_error!("`miri` cfg should not be set in build script");
+
+fn not_in_miri() -> i32 {
+    // Inline assembly definitely does not work in Miri.
+    let mut dummy = 42;
+    unsafe {
+        std::arch::asm!("/* {} */", in(reg) &mut dummy);
+    }
+    return dummy;
+}
+
+fn main() {
+    not_in_miri();
+    // Cargo calls `miri --print=cfg` to populate the `CARGO_CFG_*` env vars.
+    // Make sure that the "miri" flag is set.
+    assert!(env::var_os("CARGO_CFG_MIRI").is_some(), "cargo failed to tell us about `--cfg miri`");
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-env-changed=MIRITESTVAR");
+    println!("cargo:rustc-env=MIRITESTVAR=testval");
+
+    // Test that autocfg works. This invokes RUSTC.
+    let a = autocfg::new();
+    assert!(a.probe_sysroot_crate("std"));
+    assert!(!a.probe_sysroot_crate("doesnotexist"));
+    assert!(a.probe_rustc_version(1, 0));
+    assert!(!a.probe_rustc_version(2, 0));
+    assert!(a.probe_type("i128"));
+    assert!(!a.probe_type("doesnotexist"));
+    assert!(a.probe_trait("Send"));
+    assert!(!a.probe_trait("doesnotexist"));
+    assert!(a.probe_path("std::num"));
+    assert!(!a.probe_path("doesnotexist"));
+    assert!(a.probe_constant("i32::MAX"));
+    assert!(!a.probe_constant("doesnotexist"));
+    assert!(a.probe_expression("Box::new(0)"));
+    assert!(!a.probe_expression("doesnotexist"));
+}
diff --git a/src/tools/miri/test-cargo-miri/cdylib/Cargo.toml b/src/tools/miri/test-cargo-miri/cdylib/Cargo.toml
new file mode 100644
index 000000000000..527602e0a888
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/cdylib/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "cdylib"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[lib]
+# cargo-miri used to handle `cdylib` crate-type specially (https://github.com/rust-lang/miri/pull/1577).
+crate-type = ["cdylib"]
+
+[dependencies]
+byteorder = "1.0" # to test dependencies of sub-crates
diff --git a/src/tools/miri/test-cargo-miri/cdylib/src/lib.rs b/src/tools/miri/test-cargo-miri/cdylib/src/lib.rs
new file mode 100644
index 000000000000..e47e588251e4
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/cdylib/src/lib.rs
@@ -0,0 +1,6 @@
+use byteorder::{BigEndian, ByteOrder};
+
+#[no_mangle]
+extern "C" fn use_the_dependency() {
+    let _n = <BigEndian as ByteOrder>::read_u64(&[1, 2, 3, 4, 5, 6, 7, 8]);
+}
diff --git a/src/tools/miri/test-cargo-miri/exported-symbol-dep/Cargo.toml b/src/tools/miri/test-cargo-miri/exported-symbol-dep/Cargo.toml
new file mode 100644
index 000000000000..00c41172c3af
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/exported-symbol-dep/Cargo.toml
@@ -0,0 +1,5 @@
+[package]
+name = "exported_symbol_dep"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
diff --git a/src/tools/miri/test-cargo-miri/exported-symbol-dep/src/lib.rs b/src/tools/miri/test-cargo-miri/exported-symbol-dep/src/lib.rs
new file mode 100644
index 000000000000..5b8a314ae732
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/exported-symbol-dep/src/lib.rs
@@ -0,0 +1,13 @@
+#[no_mangle]
+fn exported_symbol() -> i32 {
+    123456
+}
+
+struct AssocFn;
+
+impl AssocFn {
+    #[no_mangle]
+    fn assoc_fn_as_exported_symbol() -> i32 {
+        -123456
+    }
+}
diff --git a/src/tools/miri/test-cargo-miri/exported-symbol/Cargo.toml b/src/tools/miri/test-cargo-miri/exported-symbol/Cargo.toml
new file mode 100644
index 000000000000..7c01be1a85f9
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/exported-symbol/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "exported_symbol"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[dependencies]
+# This will become a transitive dependency of doctests in `test-cargo-miri/src/lib.rs`,
+# and the purpose of the test is to make sure Miri can find a `#[no_mangle]` function in a
+# transitive dependency like `exported_symbol_dep`.
+exported_symbol_dep = { path = "../exported-symbol-dep" }
diff --git a/src/tools/miri/test-cargo-miri/exported-symbol/src/lib.rs b/src/tools/miri/test-cargo-miri/exported-symbol/src/lib.rs
new file mode 100644
index 000000000000..de55eb2a1a5a
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/exported-symbol/src/lib.rs
@@ -0,0 +1 @@
+extern crate exported_symbol_dep;
diff --git a/src/tools/miri/test-cargo-miri/issue-1567/Cargo.toml b/src/tools/miri/test-cargo-miri/issue-1567/Cargo.toml
new file mode 100644
index 000000000000..6a6e09036a01
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1567/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "issue_1567"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[lib]
+# Regression test for https://github.com/rust-lang/miri/issues/1567: crate must have this crate-type set.
+# It must also depend on some other crate and use that dependency (we use byteorder).
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+byteorder = "1.0"
diff --git a/src/tools/miri/test-cargo-miri/issue-1567/src/lib.rs b/src/tools/miri/test-cargo-miri/issue-1567/src/lib.rs
new file mode 100644
index 000000000000..547921683238
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1567/src/lib.rs
@@ -0,0 +1,5 @@
+use byteorder::{BigEndian, ByteOrder};
+
+pub fn use_the_dependency() {
+    let _n = <BigEndian as ByteOrder>::read_u32(&[1, 2, 3, 4]);
+}
diff --git a/src/tools/miri/test-cargo-miri/issue-1691/Cargo.toml b/src/tools/miri/test-cargo-miri/issue-1691/Cargo.toml
new file mode 100644
index 000000000000..3100cc6a60b5
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1691/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "issue_1691"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[lib]
+crate-type = ["rlib"]
diff --git a/src/tools/miri/test-cargo-miri/issue-1691/src/lib.rs b/src/tools/miri/test-cargo-miri/issue-1691/src/lib.rs
new file mode 100644
index 000000000000..efde2b58e199
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1691/src/lib.rs
@@ -0,0 +1,3 @@
+pub fn use_me() -> bool {
+    true
+}
diff --git a/src/tools/miri/test-cargo-miri/issue-1705/Cargo.toml b/src/tools/miri/test-cargo-miri/issue-1705/Cargo.toml
new file mode 100644
index 000000000000..ae63647a8881
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1705/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "issue_1705"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[lib]
+crate-type = ["lib", "staticlib", "cdylib"]
+
+[dependencies]
+byteorder = "1.0"
diff --git a/src/tools/miri/test-cargo-miri/issue-1705/src/lib.rs b/src/tools/miri/test-cargo-miri/issue-1705/src/lib.rs
new file mode 100644
index 000000000000..64633490f84b
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1705/src/lib.rs
@@ -0,0 +1,5 @@
+use byteorder::{ByteOrder, LittleEndian};
+
+pub fn use_the_dependency() {
+    let _n = <LittleEndian as ByteOrder>::read_u32(&[1, 2, 3, 4]);
+}
diff --git a/src/tools/miri/test-cargo-miri/issue-1760/Cargo.toml b/src/tools/miri/test-cargo-miri/issue-1760/Cargo.toml
new file mode 100644
index 000000000000..80925c747463
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1760/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "issue_1760"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[lib]
+proc-macro = true
diff --git a/src/tools/miri/test-cargo-miri/issue-1760/build.rs b/src/tools/miri/test-cargo-miri/issue-1760/build.rs
new file mode 100644
index 000000000000..08427fd7164f
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1760/build.rs
@@ -0,0 +1,10 @@
+use std::env;
+
+#[cfg(miri)]
+compile_error!("`miri` cfg should not be set in build script");
+
+fn main() {
+    // Cargo calls `miri --print=cfg` to populate the `CARGO_CFG_*` env vars.
+    // Make sure that the "miri" flag is not set since we are building a procedural macro crate.
+    assert!(env::var_os("CARGO_CFG_MIRI").is_none());
+}
diff --git a/src/tools/miri/test-cargo-miri/issue-1760/src/lib.rs b/src/tools/miri/test-cargo-miri/issue-1760/src/lib.rs
new file mode 100644
index 000000000000..b4f6274af444
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-1760/src/lib.rs
@@ -0,0 +1,9 @@
+use proc_macro::TokenStream;
+
+#[cfg(miri)]
+compile_error!("`miri` cfg should not be set in proc-macro");
+
+#[proc_macro]
+pub fn use_the_dependency(_: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
diff --git a/src/tools/miri/test-cargo-miri/issue-rust-86261/Cargo.toml b/src/tools/miri/test-cargo-miri/issue-rust-86261/Cargo.toml
new file mode 100644
index 000000000000..a6b65ebb5318
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-rust-86261/Cargo.toml
@@ -0,0 +1,5 @@
+[package]
+name = "issue_rust_86261"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
diff --git a/src/tools/miri/test-cargo-miri/issue-rust-86261/src/lib.rs b/src/tools/miri/test-cargo-miri/issue-rust-86261/src/lib.rs
new file mode 100644
index 000000000000..1947c38b7745
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/issue-rust-86261/src/lib.rs
@@ -0,0 +1,23 @@
+#![allow(unused_imports, unused_attributes, no_mangle_generic_items)]
+
+// Regression test for https://github.com/rust-lang/rust/issues/86261:
+// `#[no_mangle]` on a `use` item.
+#[no_mangle]
+use std::{any, boxed, io, panic, string, thread};
+
+// `#[no_mangle]` on a struct has a similar problem.
+#[no_mangle]
+pub struct NoMangleStruct;
+
+// If `#[no_mangle]` has effect on the `struct` above, calling `NoMangleStruct` will fail with
+// "multiple definitions of symbol `NoMangleStruct`" error.
+#[export_name = "NoMangleStruct"]
+fn no_mangle_struct() {}
+
+// `#[no_mangle]` on a generic function can also cause ICEs.
+#[no_mangle]
+fn no_mangle_generic<T>() {}
+
+// Same as `no_mangle_struct()` but for the `no_mangle_generic()` generic function.
+#[export_name = "no_mangle_generic"]
+fn no_mangle_generic2() {}
diff --git a/src/tools/miri/test-cargo-miri/run-test.py b/src/tools/miri/test-cargo-miri/run-test.py
new file mode 100755
index 000000000000..4485d3252ccc
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run-test.py
@@ -0,0 +1,192 @@
+#!/usr/bin/env python3
+'''
+Test whether cargo-miri works properly.
+Assumes the `MIRI_SYSROOT` env var to be set appropriately,
+and the working directory to contain the cargo-miri-test project.
+'''
+
+import sys, subprocess, os, re, difflib
+
+CGREEN  = '\33[32m'
+CBOLD   = '\33[1m'
+CEND    = '\33[0m'
+
+def fail(msg):
+    print("\nTEST FAIL: {}".format(msg))
+    sys.exit(1)
+
+def cargo_miri(cmd, quiet = True):
+    args = ["cargo", "miri", cmd]
+    if quiet:
+        args += ["-q"]
+    if 'MIRI_TEST_TARGET' in os.environ:
+        args += ["--target", os.environ['MIRI_TEST_TARGET']]
+    return args
+
+def normalize_stdout(str):
+    str = str.replace("src\\", "src/") # normalize paths across platforms
+    str = re.sub("finished in \d+\.\d\ds", "finished in $TIME", str) # the time keeps changing, obviously
+    return str
+
+def normalize_stderr(str):
+    str = re.sub("Preparing a sysroot for Miri \(target: [a-z0-9_-]+\)\.\.\. done\n", "", str) # remove leading cargo-miri setup output
+    return str
+
+def check_output(actual, path, name):
+    expected = open(path).read()
+    if expected == actual:
+        return True
+    print(f"{path} did not match reference!")
+    print(f"--- BEGIN diff {name} ---")
+    for text in difflib.unified_diff(expected.split("\n"), actual.split("\n")):
+        print(text)
+    print(f"--- END diff {name} ---")
+    return False
+
+def test(name, cmd, stdout_ref, stderr_ref, stdin=b'', env={}):
+    print("Testing {}...".format(name))
+    ## Call `cargo miri`, capture all output
+    p_env = os.environ.copy()
+    p_env.update(env)
+    p = subprocess.Popen(
+        cmd,
+        stdin=subprocess.PIPE,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        env=p_env,
+    )
+    (stdout, stderr) = p.communicate(input=stdin)
+    stdout = normalize_stdout(stdout.decode("UTF-8"))
+    stderr = normalize_stderr(stderr.decode("UTF-8"))
+
+    stdout_matches = check_output(stdout, stdout_ref, "stdout")
+    stderr_matches = check_output(stderr, stderr_ref, "stderr")
+    
+    if p.returncode == 0 and stdout_matches and stderr_matches:
+        # All good!
+        return
+    fail("exit code was {}".format(p.returncode))
+
+def test_no_rebuild(name, cmd, env={}):
+    print("Testing {}...".format(name))
+    p_env = os.environ.copy()
+    p_env.update(env)
+    p = subprocess.Popen(
+        cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        env=p_env,
+    )
+    (stdout, stderr) = p.communicate()
+    stdout = stdout.decode("UTF-8")
+    stderr = stderr.decode("UTF-8")
+    if p.returncode != 0:
+        fail("rebuild failed");
+    # Also check for 'Running' as a sanity check.
+    if stderr.count(" Compiling ") > 0 or stderr.count(" Running ") == 0:
+        print("--- BEGIN stderr ---")
+        print(stderr, end="")
+        print("--- END stderr ---")
+        fail("Something was being rebuilt when it should not be (or we got no output)");
+
+def test_cargo_miri_run():
+    test("`cargo miri run` (no isolation)",
+        cargo_miri("run"),
+        "run.default.stdout.ref", "run.default.stderr.ref",
+        stdin=b'12\n21\n',
+        env={
+            'MIRIFLAGS': "-Zmiri-disable-isolation",
+            'MIRITESTVAR': "wrongval", # make sure the build.rs value takes precedence
+        },
+    )
+    # Special test: run it again *without* `-q` to make sure nothing is being rebuilt (Miri issue #1722)
+    test_no_rebuild("`cargo miri run` (no rebuild)",
+        cargo_miri("run", quiet=False) + ["--", ""],
+        env={'MIRITESTVAR': "wrongval"}, # changing the env var causes a rebuild (re-runs build.rs),
+                                         # so keep it set
+    )
+    test("`cargo miri run` (with arguments and target)",
+        cargo_miri("run") + ["--bin", "cargo-miri-test", "--", "hello world", '"hello world"', r'he\\llo\"world'],
+        "run.args.stdout.ref", "run.args.stderr.ref",
+    )
+    test("`cargo miri r` (subcrate, no isolation)",
+        cargo_miri("r") + ["-p", "subcrate"],
+        "run.subcrate.stdout.ref", "run.subcrate.stderr.ref",
+        env={'MIRIFLAGS': "-Zmiri-disable-isolation"},
+    )
+    test("`cargo miri run` (custom target dir)",
+        # Attempt to confuse the argument parser.
+        cargo_miri("run") + ["--target-dir=custom-run", "--", "--target-dir=target/custom-run"],
+        "run.args.stdout.ref", "run.custom-target-dir.stderr.ref",
+    )
+
+def test_cargo_miri_test():
+    # rustdoc is not run on foreign targets
+    is_foreign = 'MIRI_TEST_TARGET' in os.environ
+    default_ref = "test.cross-target.stdout.ref" if is_foreign else "test.default.stdout.ref"
+    filter_ref = "test.filter.cross-target.stdout.ref" if is_foreign else "test.filter.stdout.ref"
+
+    # macOS needs permissive provenance inside getrandom_1.
+    test("`cargo miri test`",
+        cargo_miri("test"),
+        default_ref, "test.stderr-empty.ref",
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance -Zmiri-seed=feed"},
+    )
+    test("`cargo miri test` (no isolation, no doctests)",
+        cargo_miri("test") + ["--bins", "--tests"], # no `--lib`, we disabled that in `Cargo.toml`
+        "test.cross-target.stdout.ref", "test.stderr-empty.ref",
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance -Zmiri-disable-isolation"},
+    )
+    test("`cargo miri test` (with filter)",
+        cargo_miri("test") + ["--", "--format=pretty", "pl"],
+        filter_ref, "test.stderr-empty.ref",
+    )
+    test("`cargo miri test` (test target)",
+        cargo_miri("test") + ["--test", "test", "--", "--format=pretty"],
+        "test.test-target.stdout.ref", "test.stderr-empty.ref",
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance"},
+    )
+    test("`cargo miri test` (bin target)",
+        cargo_miri("test") + ["--bin", "cargo-miri-test", "--", "--format=pretty"],
+        "test.bin-target.stdout.ref", "test.stderr-empty.ref",
+    )
+    test("`cargo miri t` (subcrate, no isolation)",
+        cargo_miri("t") + ["-p", "subcrate"],
+        "test.subcrate.stdout.ref", "test.stderr-proc-macro.ref",
+        env={'MIRIFLAGS': "-Zmiri-disable-isolation"},
+    )
+    test("`cargo miri test` (subcrate, doctests)",
+        cargo_miri("test") + ["-p", "subcrate", "--doc"],
+        "test.stdout-empty.ref", "test.stderr-proc-macro-doctest.ref",
+    )
+    test("`cargo miri test` (custom target dir)",
+        cargo_miri("test") + ["--target-dir=custom-test"],
+        default_ref, "test.stderr-empty.ref",
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance"},
+    )
+    del os.environ["CARGO_TARGET_DIR"] # this overrides `build.target-dir` passed by `--config`, so unset it
+    test("`cargo miri test` (config-cli)",
+        cargo_miri("test") + ["--config=build.target-dir=\"config-cli\"", "-Zunstable-options"],
+        default_ref, "test.stderr-empty.ref",
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance"},
+    )
+
+os.chdir(os.path.dirname(os.path.realpath(__file__)))
+os.environ["CARGO_TARGET_DIR"] = "target" # this affects the location of the target directory that we need to check
+os.environ["RUST_TEST_NOCAPTURE"] = "0" # this affects test output, so make sure it is not set
+os.environ["RUST_TEST_THREADS"] = "1" # avoid non-deterministic output due to concurrent test runs
+
+target_str = " for target {}".format(os.environ['MIRI_TEST_TARGET']) if 'MIRI_TEST_TARGET' in os.environ else ""
+print(CGREEN + CBOLD + "## Running `cargo miri` tests{}".format(target_str) + CEND)
+
+test_cargo_miri_run()
+test_cargo_miri_test()
+# Ensure we did not create anything outside the expected target dir.
+for target_dir in ["target", "custom-run", "custom-test", "config-cli"]:
+    if os.listdir(target_dir) != ["miri"]:
+        fail(f"`{target_dir}` contains unexpected files")
+    # Ensure something exists inside that target dir.
+    os.access(os.path.join(target_dir, "miri", "debug", "deps"), os.F_OK)
+
+print("\nTEST SUCCESSFUL!")
+sys.exit(0)
diff --git a/src/tools/miri/test-cargo-miri/run.args.stderr.ref b/src/tools/miri/test-cargo-miri/run.args.stderr.ref
new file mode 100644
index 000000000000..01bb8952322b
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run.args.stderr.ref
@@ -0,0 +1,4 @@
+main
+hello world
+"hello world"
+he\\llo\"world
diff --git a/src/tools/miri/test-cargo-miri/run.args.stdout.ref b/src/tools/miri/test-cargo-miri/run.args.stdout.ref
new file mode 100644
index 000000000000..6710f307cb26
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run.args.stdout.ref
@@ -0,0 +1 @@
+0x01020304
diff --git a/src/tools/miri/test-cargo-miri/run.custom-target-dir.stderr.ref b/src/tools/miri/test-cargo-miri/run.custom-target-dir.stderr.ref
new file mode 100644
index 000000000000..4395ff8879b9
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run.custom-target-dir.stderr.ref
@@ -0,0 +1,2 @@
+main
+--target-dir=target/custom-run
diff --git a/src/tools/miri/test-cargo-miri/run.default.stderr.ref b/src/tools/miri/test-cargo-miri/run.default.stderr.ref
new file mode 100644
index 000000000000..ba2906d0666c
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run.default.stderr.ref
@@ -0,0 +1 @@
+main
diff --git a/src/tools/miri/test-cargo-miri/run.default.stdout.ref b/src/tools/miri/test-cargo-miri/run.default.stdout.ref
new file mode 100644
index 000000000000..2eab8df967d5
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run.default.stdout.ref
@@ -0,0 +1,3 @@
+0x01020304
+24
+42
diff --git a/src/tools/miri/test-cargo-miri/run.subcrate.stderr.ref b/src/tools/miri/test-cargo-miri/run.subcrate.stderr.ref
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/src/tools/miri/test-cargo-miri/run.subcrate.stdout.ref b/src/tools/miri/test-cargo-miri/run.subcrate.stdout.ref
new file mode 100644
index 000000000000..53340a502381
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/run.subcrate.stdout.ref
@@ -0,0 +1 @@
+subcrate running
diff --git a/src/tools/miri/test-cargo-miri/src/lib.rs b/src/tools/miri/test-cargo-miri/src/lib.rs
new file mode 100644
index 000000000000..66c8aa2eac57
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/src/lib.rs
@@ -0,0 +1,27 @@
+/// Doc-test test
+/// ```rust
+/// assert!(cargo_miri_test::make_true());
+/// ```
+/// ```rust,no_run
+/// assert!(!cargo_miri_test::make_true());
+/// ```
+/// ```rust,compile_fail
+/// assert!(cargo_miri_test::make_true() == 5);
+/// ```
+#[no_mangle]
+pub fn make_true() -> bool {
+    issue_1567::use_the_dependency();
+    issue_1705::use_the_dependency();
+    issue_1760::use_the_dependency!();
+    issue_1691::use_me()
+}
+
+/// ```rust
+/// cargo_miri_test::miri_only_fn();
+/// ```
+#[cfg(miri)]
+pub fn miri_only_fn() {}
+
+pub fn main() {
+    println!("imported main");
+}
diff --git a/src/tools/miri/test-cargo-miri/src/main.rs b/src/tools/miri/test-cargo-miri/src/main.rs
new file mode 100644
index 000000000000..41c52b701702
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/src/main.rs
@@ -0,0 +1,78 @@
+use byteorder::{BigEndian, ByteOrder};
+use std::env;
+#[cfg(unix)]
+use std::io::{self, BufRead};
+
+fn main() {
+    // Check env var set by `build.rs`.
+    assert_eq!(env!("MIRITESTVAR"), "testval");
+
+    // Exercise external crate, printing to stdout.
+    let buf = &[1, 2, 3, 4];
+    let n = <BigEndian as ByteOrder>::read_u32(buf);
+    assert_eq!(n, 0x01020304);
+    println!("{:#010x}", n);
+
+    // Access program arguments, printing to stderr.
+    for arg in std::env::args() {
+        eprintln!("{}", arg);
+    }
+
+    // If there were no arguments, access stdin and test working dir.
+    // (We rely on the test runner to always disable isolation when passing no arguments.)
+    if std::env::args().len() <= 1 {
+        // CWD should be crate root.
+        // We have to normalize slashes, as the env var might be set for a different target's conventions.
+        let env_dir = env::current_dir().unwrap();
+        let env_dir = env_dir.to_string_lossy().replace("\\", "/");
+        let crate_dir = env::var_os("CARGO_MANIFEST_DIR").unwrap();
+        let crate_dir = crate_dir.to_string_lossy().replace("\\", "/");
+        assert_eq!(env_dir, crate_dir);
+
+        #[cfg(unix)]
+        for line in io::stdin().lock().lines() {
+            let num: i32 = line.unwrap().parse().unwrap();
+            println!("{}", 2 * num);
+        }
+        // On non-Unix, reading from stdin is not supported. So we hard-code the right answer.
+        #[cfg(not(unix))]
+        {
+            println!("24");
+            println!("42");
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use byteorder_2::{BigEndian, ByteOrder};
+
+    // Make sure in-crate tests with dev-dependencies work
+    #[test]
+    fn dev_dependency() {
+        let _n = <BigEndian as ByteOrder>::read_u64(&[1, 2, 3, 4, 5, 6, 7, 8]);
+    }
+
+    #[test]
+    fn exported_symbol() {
+        extern crate cargo_miri_test;
+        extern crate exported_symbol;
+        extern crate issue_rust_86261;
+        // Test calling exported symbols in (transitive) dependencies.
+        // Repeat calls to make sure the `Instance` cache is not broken.
+        for _ in 0..3 {
+            extern "Rust" {
+                fn exported_symbol() -> i32;
+                fn assoc_fn_as_exported_symbol() -> i32;
+                fn make_true() -> bool;
+                fn NoMangleStruct();
+                fn no_mangle_generic();
+            }
+            assert_eq!(unsafe { exported_symbol() }, 123456);
+            assert_eq!(unsafe { assoc_fn_as_exported_symbol() }, -123456);
+            assert!(unsafe { make_true() });
+            unsafe { NoMangleStruct() }
+            unsafe { no_mangle_generic() }
+        }
+    }
+}
diff --git a/src/tools/miri/test-cargo-miri/subcrate/Cargo.toml b/src/tools/miri/test-cargo-miri/subcrate/Cargo.toml
new file mode 100644
index 000000000000..06b1ce1cba4b
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/subcrate/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "subcrate"
+version = "0.1.0"
+authors = ["Miri Team"]
+edition = "2018"
+
+[lib]
+proc-macro = true
+doctest = false
+
+[[bin]]
+name = "subcrate"
+path = "main.rs"
+
+[[test]]
+name = "subtest"
+path = "test.rs"
+harness = false
+
+[dev-dependencies]
+byteorder = "1.0"
diff --git a/src/tools/miri/test-cargo-miri/subcrate/main.rs b/src/tools/miri/test-cargo-miri/subcrate/main.rs
new file mode 100644
index 000000000000..4ce80b370722
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/subcrate/main.rs
@@ -0,0 +1,16 @@
+use std::env;
+use std::path::PathBuf;
+
+fn main() {
+    println!("subcrate running");
+
+    // CWD should be workspace root, i.e., one level up from crate root.
+    // We have to normalize slashes, as the env var might be set for a different target's conventions.
+    let env_dir = env::current_dir().unwrap();
+    let env_dir = env_dir.to_string_lossy().replace("\\", "/");
+    let crate_dir = env::var_os("CARGO_MANIFEST_DIR").unwrap();
+    let crate_dir = crate_dir.to_string_lossy().replace("\\", "/");
+    let crate_dir = PathBuf::from(crate_dir);
+    let crate_dir = crate_dir.parent().unwrap().to_string_lossy();
+    assert_eq!(env_dir, crate_dir);
+}
diff --git a/src/tools/miri/test-cargo-miri/subcrate/src/lib.rs b/src/tools/miri/test-cargo-miri/subcrate/src/lib.rs
new file mode 100644
index 000000000000..2ccb6704b05e
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/subcrate/src/lib.rs
@@ -0,0 +1,5 @@
+#[cfg(doctest)]
+compile_error!("rustdoc should not touch me");
+
+#[cfg(test)]
+compile_error!("Miri should not touch me");
diff --git a/src/tools/miri/test-cargo-miri/subcrate/test.rs b/src/tools/miri/test-cargo-miri/subcrate/test.rs
new file mode 100644
index 000000000000..77e3c2878ca0
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/subcrate/test.rs
@@ -0,0 +1,18 @@
+use std::env;
+
+use byteorder::{ByteOrder, LittleEndian};
+
+fn main() {
+    println!("subcrate testing");
+
+    // CWD should be crate root.
+    // We have to normalize slashes, as the env var might be set for a different target's conventions.
+    let env_dir = env::current_dir().unwrap();
+    let env_dir = env_dir.to_string_lossy().replace("\\", "/");
+    let crate_dir = env::var_os("CARGO_MANIFEST_DIR").unwrap();
+    let crate_dir = crate_dir.to_string_lossy().replace("\\", "/");
+    assert_eq!(env_dir, crate_dir);
+
+    // Make sure we can call dev-dependencies.
+    let _n = <LittleEndian as ByteOrder>::read_u32(&[1, 2, 3, 4]);
+}
diff --git a/src/tools/miri/test-cargo-miri/test.bin-target.stdout.ref b/src/tools/miri/test-cargo-miri/test.bin-target.stdout.ref
new file mode 100644
index 000000000000..5264530160bc
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.bin-target.stdout.ref
@@ -0,0 +1,7 @@
+
+running 2 tests
+test test::dev_dependency ... ok
+test test::exported_symbol ... ok
+
+test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+
diff --git a/src/tools/miri/test-cargo-miri/test.cross-target.stdout.ref b/src/tools/miri/test-cargo-miri/test.cross-target.stdout.ref
new file mode 100644
index 000000000000..8c543e479f4e
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.cross-target.stdout.ref
@@ -0,0 +1,11 @@
+
+running 2 tests
+..
+test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+
+imported main
+
+running 6 tests
+...i..
+test result: ok. 5 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out
+
diff --git a/src/tools/miri/test-cargo-miri/test.default.stdout.ref b/src/tools/miri/test-cargo-miri/test.default.stdout.ref
new file mode 100644
index 000000000000..9a17f3d61b6a
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.default.stdout.ref
@@ -0,0 +1,16 @@
+
+running 2 tests
+..
+test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+
+imported main
+
+running 6 tests
+...i..
+test result: ok. 5 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out
+
+
+running 4 tests
+....
+test result: ok. 4 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+
diff --git a/src/tools/miri/test-cargo-miri/test.filter.cross-target.stdout.ref b/src/tools/miri/test-cargo-miri/test.filter.cross-target.stdout.ref
new file mode 100644
index 000000000000..bb0282d6c916
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.filter.cross-target.stdout.ref
@@ -0,0 +1,12 @@
+
+running 0 tests
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 2 filtered out
+
+imported main
+
+running 1 test
+test simple ... ok
+
+test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 5 filtered out
+
diff --git a/src/tools/miri/test-cargo-miri/test.filter.stdout.ref b/src/tools/miri/test-cargo-miri/test.filter.stdout.ref
new file mode 100644
index 000000000000..c618956656a8
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.filter.stdout.ref
@@ -0,0 +1,17 @@
+
+running 0 tests
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 2 filtered out
+
+imported main
+
+running 1 test
+test simple ... ok
+
+test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 5 filtered out
+
+
+running 0 tests
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 4 filtered out; finished in $TIME
+
diff --git a/src/tools/miri/test-cargo-miri/test.stderr-empty.ref b/src/tools/miri/test-cargo-miri/test.stderr-empty.ref
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/src/tools/miri/test-cargo-miri/test.stderr-proc-macro-doctest.ref b/src/tools/miri/test-cargo-miri/test.stderr-proc-macro-doctest.ref
new file mode 100644
index 000000000000..ca5e3a2392db
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.stderr-proc-macro-doctest.ref
@@ -0,0 +1 @@
+Running doctests of `proc-macro` crates is not currently supported by Miri.
diff --git a/src/tools/miri/test-cargo-miri/test.stderr-proc-macro.ref b/src/tools/miri/test-cargo-miri/test.stderr-proc-macro.ref
new file mode 100644
index 000000000000..4983250917b5
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.stderr-proc-macro.ref
@@ -0,0 +1 @@
+Running unit tests of `proc-macro` crates is not currently supported by Miri.
diff --git a/src/tools/miri/test-cargo-miri/test.stdout-empty.ref b/src/tools/miri/test-cargo-miri/test.stdout-empty.ref
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/src/tools/miri/test-cargo-miri/test.subcrate.stdout.ref b/src/tools/miri/test-cargo-miri/test.subcrate.stdout.ref
new file mode 100644
index 000000000000..67e5c7f8e920
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.subcrate.stdout.ref
@@ -0,0 +1,6 @@
+
+running 0 tests
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+
+subcrate testing
diff --git a/src/tools/miri/test-cargo-miri/test.test-target.stdout.ref b/src/tools/miri/test-cargo-miri/test.test-target.stdout.ref
new file mode 100644
index 000000000000..dd59b32b780c
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/test.test-target.stdout.ref
@@ -0,0 +1,11 @@
+
+running 6 tests
+test cargo_env ... ok
+test deps ... ok
+test do_panic - should panic ... ok
+test does_not_work_on_miri ... ignored
+test fail_index_check - should panic ... ok
+test simple ... ok
+
+test result: ok. 5 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out
+
diff --git a/src/tools/miri/test-cargo-miri/tests/main.rs b/src/tools/miri/test-cargo-miri/tests/main.rs
new file mode 100644
index 000000000000..bb94c8f37876
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/tests/main.rs
@@ -0,0 +1,3 @@
+#![feature(imported_main)]
+
+use cargo_miri_test::main;
diff --git a/src/tools/miri/test-cargo-miri/tests/test.rs b/src/tools/miri/test-cargo-miri/tests/test.rs
new file mode 100644
index 000000000000..9ed215289396
--- /dev/null
+++ b/src/tools/miri/test-cargo-miri/tests/test.rs
@@ -0,0 +1,49 @@
+#[test]
+fn simple() {
+    assert_eq!(4, 4);
+}
+
+// A test that won't work on miri (tests disabling tests).
+#[test]
+#[cfg_attr(miri, ignore)]
+fn does_not_work_on_miri() {
+    // Only do this where inline assembly is stable.
+    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+    unsafe {
+        std::arch::asm!("foo");
+    }
+}
+
+// Make sure integration tests can access both dependencies and dev-dependencies
+#[test]
+fn deps() {
+    {
+        use byteorder::{BigEndian, ByteOrder};
+        let _n = <BigEndian as ByteOrder>::read_u64(&[1, 2, 3, 4, 5, 6, 7, 8]);
+    }
+    {
+        use byteorder_2::{BigEndian, ByteOrder};
+        let _n = <BigEndian as ByteOrder>::read_u64(&[1, 2, 3, 4, 5, 6, 7, 8]);
+    }
+}
+
+#[test]
+fn cargo_env() {
+    assert_eq!(env!("CARGO_PKG_NAME"), "cargo-miri-test");
+    env!("CARGO_BIN_EXE_cargo-miri-test"); // Asserts that this exists.
+}
+
+#[test]
+#[should_panic(expected = "Explicit panic")]
+fn do_panic() // In large, friendly letters :)
+{
+    panic!("Explicit panic from test!");
+}
+
+// A different way of raising a panic
+#[test]
+#[allow(unconditional_panic)]
+#[should_panic(expected = "the len is 0 but the index is 42")]
+fn fail_index_check() {
+    [][42]
+}
diff --git a/src/tools/miri/test_dependencies/Cargo.lock b/src/tools/miri/test_dependencies/Cargo.lock
new file mode 100644
index 000000000000..d4b32e2c29a2
--- /dev/null
+++ b/src/tools/miri/test_dependencies/Cargo.lock
@@ -0,0 +1,388 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
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+
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+ "cfg-if",
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+ "libc",
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+ "libc",
+ "log",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+ "windows-sys",
+]
+
+[[package]]
+name = "miri-test-deps"
+version = "0.1.0"
+dependencies = [
+ "getrandom 0.1.16",
+ "getrandom 0.2.7",
+ "libc",
+ "num_cpus",
+ "page_size",
+ "rand",
+ "tokio",
+]
+
+[[package]]
+name = "num_cpus"
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+ "hermit-abi",
+ "libc",
+]
+
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+ "parking_lot_core",
+]
+
+[[package]]
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+ "windows-sys",
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+ "libc",
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+ "rand_core",
+]
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+ "rand_core",
+]
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+ "unicode-ident",
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+ "bytes",
+ "libc",
+ "memchr",
+ "mio",
+ "num_cpus",
+ "once_cell",
+ "parking_lot",
+ "pin-project-lite",
+ "signal-hook-registry",
+ "socket2",
+ "tokio-macros",
+ "winapi",
+]
+
+[[package]]
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+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
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+
+[[package]]
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+
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+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
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+
+[[package]]
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+
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+checksum = "ea04155a16a59f9eab786fe12a4a450e75cdb175f9e0d80da1e17db09f55b8d2"
+dependencies = [
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9bb8c3fd39ade2d67e9874ac4f3db21f0d710bee00fe7cab16949ec184eeaa47"
+
+[[package]]
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+version = "0.36.1"
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+checksum = "180e6ccf01daf4c426b846dfc66db1fc518f074baa793aa7d9b9aaeffad6a3b6"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2e7917148b2812d1eeafaeb22a97e4813dfa60a3f8f78ebe204bcc88f12f024"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4dcd171b8776c41b97521e5da127a2d86ad280114807d0b2ab1e462bc764d9e1"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.36.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c811ca4a8c853ef420abd8592ba53ddbbac90410fab6903b3e79972a631f7680"
diff --git a/src/tools/miri/test_dependencies/Cargo.toml b/src/tools/miri/test_dependencies/Cargo.toml
new file mode 100644
index 000000000000..58f731f91d0f
--- /dev/null
+++ b/src/tools/miri/test_dependencies/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+authors = ["Miri Team"]
+description = "dependencies that unit tests can have"
+license = "MIT OR Apache-2.0"
+name = "miri-test-deps"
+repository = "https://github.com/rust-lang/miri"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+# all dependencies (and their transitive ones) listed here can be used in `tests/`.
+tokio = { version = "1.0", features = ["full"] }
+libc = "0.2"
+page_size = "0.4.1"
+num_cpus = "1.10.1"
+
+getrandom_1 = { package = "getrandom", version = "0.1" }
+getrandom_2 = { package = "getrandom", version = "0.2" }
+rand = { version = "0.8", features = ["small_rng"] }
+
+[workspace]
diff --git a/src/tools/miri/test_dependencies/src/main.rs b/src/tools/miri/test_dependencies/src/main.rs
new file mode 100644
index 000000000000..f328e4d9d04c
--- /dev/null
+++ b/src/tools/miri/test_dependencies/src/main.rs
@@ -0,0 +1 @@
+fn main() {}
diff --git a/src/tools/miri/tests/compiletest.rs b/src/tools/miri/tests/compiletest.rs
new file mode 100644
index 000000000000..6b5668e2d6c4
--- /dev/null
+++ b/src/tools/miri/tests/compiletest.rs
@@ -0,0 +1,220 @@
+use colored::*;
+use regex::Regex;
+use std::path::{Path, PathBuf};
+use std::{env, process::Command};
+use ui_test::{color_eyre::Result, Config, Mode, OutputConflictHandling};
+
+fn miri_path() -> PathBuf {
+    PathBuf::from(option_env!("MIRI").unwrap_or(env!("CARGO_BIN_EXE_miri")))
+}
+
+// Build the shared object file for testing external C function calls.
+fn build_so_for_c_ffi_tests() -> PathBuf {
+    let cc = option_env!("CC").unwrap_or("cc");
+    // Target directory that we can write to.
+    let so_target_dir = Path::new(&env::var_os("CARGO_TARGET_DIR").unwrap()).join("miri-extern-so");
+    // Create the directory if it does not already exist.
+    std::fs::create_dir_all(&so_target_dir)
+        .expect("Failed to create directory for shared object file");
+    let so_file_path = so_target_dir.join("libtestlib.so");
+    let cc_output = Command::new(cc)
+        .args([
+            "-shared",
+            "-o",
+            so_file_path.to_str().unwrap(),
+            "tests/extern-so/test.c",
+            // Only add the functions specified in libcode.version to the shared object file.
+            // This is to avoid automatically adding `malloc`, etc.
+            // Source: https://anadoxin.org/blog/control-over-symbol-exports-in-gcc.html/
+            "-fPIC",
+            "-Wl,--version-script=tests/extern-so/libcode.version",
+        ])
+        .output()
+        .expect("failed to generate shared object file for testing external C function calls");
+    if !cc_output.status.success() {
+        panic!("error in generating shared object file for testing external C function calls");
+    }
+    so_file_path
+}
+
+fn run_tests(
+    mode: Mode,
+    path: &str,
+    target: Option<String>,
+    with_dependencies: bool,
+) -> Result<()> {
+    let mut config = Config {
+        target,
+        stderr_filters: STDERR.clone(),
+        stdout_filters: STDOUT.clone(),
+        root_dir: PathBuf::from(path),
+        mode,
+        program: miri_path(),
+        quiet: false,
+        ..Config::default()
+    };
+
+    let in_rustc_test_suite = option_env!("RUSTC_STAGE").is_some();
+
+    // Add some flags we always want.
+    config.args.push("--edition".into());
+    config.args.push("2018".into());
+    if in_rustc_test_suite {
+        // Less aggressive warnings to make the rustc toolstate management less painful.
+        // (We often get warnings when e.g. a feature gets stabilized or some lint gets added/improved.)
+        config.args.push("-Astable-features".into());
+        config.args.push("-Aunused".into());
+    } else {
+        config.args.push("-Dwarnings".into());
+        config.args.push("-Dunused".into());
+    }
+    if let Ok(extra_flags) = env::var("MIRIFLAGS") {
+        for flag in extra_flags.split_whitespace() {
+            config.args.push(flag.into());
+        }
+    }
+    config.args.push("-Zui-testing".into());
+    if let Some(target) = &config.target {
+        config.args.push("--target".into());
+        config.args.push(target.into());
+    }
+
+    // If we're on linux, and we're testing the extern-so functionality,
+    // then build the shared object file for testing external C function calls
+    // and push the relevant compiler flag.
+    if cfg!(target_os = "linux") && path.starts_with("tests/extern-so/") {
+        let so_file_path = build_so_for_c_ffi_tests();
+        let mut flag = std::ffi::OsString::from("-Zmiri-extern-so-file=");
+        flag.push(so_file_path.into_os_string());
+        config.args.push(flag);
+    }
+
+    let skip_ui_checks = env::var_os("MIRI_SKIP_UI_CHECKS").is_some();
+
+    config.output_conflict_handling = match (env::var_os("MIRI_BLESS").is_some(), skip_ui_checks) {
+        (false, false) => OutputConflictHandling::Error,
+        (true, false) => OutputConflictHandling::Bless,
+        (false, true) => OutputConflictHandling::Ignore,
+        (true, true) => panic!("cannot use MIRI_BLESS and MIRI_SKIP_UI_CHECKS at the same time"),
+    };
+
+    // Handle command-line arguments.
+    config.path_filter.extend(std::env::args().skip(1).filter(|arg| {
+        match &**arg {
+            "--quiet" => {
+                config.quiet = true;
+                false
+            }
+            _ => true,
+        }
+    }));
+
+    let use_std = env::var_os("MIRI_NO_STD").is_none();
+
+    if with_dependencies && use_std {
+        config.dependencies_crate_manifest_path =
+            Some(Path::new("test_dependencies").join("Cargo.toml"));
+        config.dependency_builder.args = vec![
+            "run".into(),
+            "--manifest-path".into(),
+            "cargo-miri/Cargo.toml".into(),
+            "--".into(),
+            "miri".into(),
+            "run".into(), // There is no `cargo miri build` so we just use `cargo miri run`.
+        ];
+    }
+    ui_test::run_tests(config)
+}
+
+macro_rules! regexes {
+    ($name:ident: $($regex:expr => $replacement:expr,)*) => {lazy_static::lazy_static! {
+        static ref $name: Vec<(Regex, &'static str)> = vec![
+            $((Regex::new($regex).unwrap(), $replacement),)*
+        ];
+    }};
+}
+
+regexes! {
+    STDOUT:
+    // Windows file paths
+    r"\\"                           => "/",
+}
+
+regexes! {
+    STDERR:
+    // erase line and column info
+    r"\.rs:[0-9]+:[0-9]+(: [0-9]+:[0-9]+)?" => ".rs:LL:CC",
+    // erase alloc ids
+    "alloc[0-9]+"                    => "ALLOC",
+    // erase Stacked Borrows tags
+    "<[0-9]+>"                       => "<TAG>",
+    // erase whitespace that differs between platforms
+    r" +at (.*\.rs)"                 => " at $1",
+    // erase generics in backtraces
+    "([0-9]+: .*)::<.*>"             => "$1",
+    // erase addresses in backtraces
+    "([0-9]+: ) +0x[0-9a-f]+ - (.*)" => "$1$2",
+    // erase long hexadecimals
+    r"0x[0-9a-fA-F]+[0-9a-fA-F]{2,2}" => "$$HEX",
+    // erase specific alignments
+    "alignment [0-9]+"               => "alignment ALIGN",
+    // erase thread caller ids
+    r"call [0-9]+"                  => "call ID",
+    // erase platform module paths
+    "sys::[a-z]+::"                  => "sys::PLATFORM::",
+    // Windows file paths
+    r"\\"                           => "/",
+    // erase Rust stdlib path
+    "[^ `]*/(rust[^/]*|checkout)/library/" => "RUSTLIB/",
+    // erase platform file paths
+    "sys/[a-z]+/"                    => "sys/PLATFORM/",
+    // erase paths into the crate registry
+    r"[^ ]*/\.?cargo/registry/.*/(.*\.rs)"  => "CARGO_REGISTRY/.../$1",
+}
+
+enum Dependencies {
+    WithDependencies,
+    WithoutDependencies,
+}
+
+use Dependencies::*;
+
+fn ui(mode: Mode, path: &str, with_dependencies: Dependencies) -> Result<()> {
+    let target = get_target();
+
+    let msg = format!(
+        "## Running ui tests in {path} against miri for {}",
+        target.as_deref().unwrap_or("host")
+    );
+    eprintln!("{}", msg.green().bold());
+
+    let with_dependencies = match with_dependencies {
+        WithDependencies => true,
+        WithoutDependencies => false,
+    };
+    run_tests(mode, path, target, with_dependencies)
+}
+
+fn get_target() -> Option<String> {
+    env::var("MIRI_TEST_TARGET").ok()
+}
+
+fn main() -> Result<()> {
+    ui_test::color_eyre::install()?;
+
+    // Add a test env var to do environment communication tests.
+    env::set_var("MIRI_ENV_VAR_TEST", "0");
+    // Let the tests know where to store temp files (they might run for a different target, which can make this hard to find).
+    env::set_var("MIRI_TEMP", env::temp_dir());
+
+    ui(Mode::Pass, "tests/pass", WithoutDependencies)?;
+    ui(Mode::Pass, "tests/pass-dep", WithDependencies)?;
+    ui(Mode::Panic, "tests/panic", WithDependencies)?;
+    ui(Mode::Fail { require_patterns: true }, "tests/fail", WithDependencies)?;
+    if cfg!(target_os = "linux") {
+        ui(Mode::Pass, "tests/extern-so/pass", WithoutDependencies)?;
+        ui(Mode::Fail { require_patterns: true }, "tests/extern-so/fail", WithDependencies)?;
+    }
+
+    Ok(())
+}
diff --git a/src/tools/miri/tests/extern-so/fail/function_not_in_so.rs b/src/tools/miri/tests/extern-so/fail/function_not_in_so.rs
new file mode 100644
index 000000000000..3aaeb632cad7
--- /dev/null
+++ b/src/tools/miri/tests/extern-so/fail/function_not_in_so.rs
@@ -0,0 +1,12 @@
+//@only-target-linux
+//@only-on-host
+
+extern "C" {
+    fn foo();
+}
+
+fn main() {
+    unsafe {
+        foo(); //~ ERROR: unsupported operation: can't call foreign function: foo
+    }
+}
diff --git a/src/tools/miri/tests/extern-so/fail/function_not_in_so.stderr b/src/tools/miri/tests/extern-so/fail/function_not_in_so.stderr
new file mode 100644
index 000000000000..f649f0ae43e3
--- /dev/null
+++ b/src/tools/miri/tests/extern-so/fail/function_not_in_so.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: can't call foreign function: foo
+  --> $DIR/function_not_in_so.rs:LL:CC
+   |
+LL |         foo();
+   |         ^^^^^ can't call foreign function: foo
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/function_not_in_so.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/extern-so/libcode.version b/src/tools/miri/tests/extern-so/libcode.version
new file mode 100644
index 000000000000..0f04b9aaebb3
--- /dev/null
+++ b/src/tools/miri/tests/extern-so/libcode.version
@@ -0,0 +1,9 @@
+CODEABI_1.0 {
+    global: *add_one_int*; 
+        *printer*; 
+        *test_stack_spill*; 
+        *get_unsigned_int*; 
+        *add_int16*;
+        *add_short_to_long*;
+    local: *;
+};
diff --git a/src/tools/miri/tests/extern-so/pass/call_extern_c_fn.rs b/src/tools/miri/tests/extern-so/pass/call_extern_c_fn.rs
new file mode 100644
index 000000000000..1e1d0b11e99f
--- /dev/null
+++ b/src/tools/miri/tests/extern-so/pass/call_extern_c_fn.rs
@@ -0,0 +1,46 @@
+//@only-target-linux
+//@only-on-host
+
+extern "C" {
+    fn add_one_int(x: i32) -> i32;
+    fn add_int16(x: i16) -> i16;
+    fn test_stack_spill(
+        a: i32,
+        b: i32,
+        c: i32,
+        d: i32,
+        e: i32,
+        f: i32,
+        g: i32,
+        h: i32,
+        i: i32,
+        j: i32,
+        k: i32,
+        l: i32,
+    ) -> i32;
+    fn add_short_to_long(x: i16, y: i64) -> i64;
+    fn get_unsigned_int() -> u32;
+    fn printer();
+}
+
+fn main() {
+    unsafe {
+        // test function that adds 2 to a provided int
+        assert_eq!(add_one_int(1), 3);
+
+        // test function that takes the sum of its 12 arguments
+        assert_eq!(test_stack_spill(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), 78);
+
+        // test function that adds 3 to a 16 bit int
+        assert_eq!(add_int16(-1i16), 2i16);
+
+        // test function that adds an i16 to an i64
+        assert_eq!(add_short_to_long(-1i16, 123456789123i64), 123456789122i64);
+
+        // test function that returns -10 as an unsigned int
+        assert_eq!(get_unsigned_int(), (-10i32) as u32);
+
+        // test void function that prints from C
+        printer();
+    }
+}
diff --git a/src/tools/miri/tests/extern-so/pass/call_extern_c_fn.stdout b/src/tools/miri/tests/extern-so/pass/call_extern_c_fn.stdout
new file mode 100644
index 000000000000..7ba13d2d7b02
--- /dev/null
+++ b/src/tools/miri/tests/extern-so/pass/call_extern_c_fn.stdout
@@ -0,0 +1 @@
+printing from C
diff --git a/src/tools/miri/tests/extern-so/test.c b/src/tools/miri/tests/extern-so/test.c
new file mode 100644
index 000000000000..68714f1743b6
--- /dev/null
+++ b/src/tools/miri/tests/extern-so/test.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+
+int add_one_int(int x) {
+  return 2 + x;
+}
+
+void printer() {
+  printf("printing from C\n");
+}
+
+// function with many arguments, to test functionality when some args are stored
+// on the stack
+int test_stack_spill(int a, int b, int c, int d, int e, int f, int g, int h, int i, int j, int k, int l) {
+  return a+b+c+d+e+f+g+h+i+j+k+l;
+}
+
+unsigned int get_unsigned_int() {
+  return -10;
+}
+
+short add_int16(short x) {
+  return x + 3;
+}
+
+long add_short_to_long(short x, long y) {
+  return x + y;
+}
diff --git a/src/tools/miri/tests/fail/abort-terminator.rs b/src/tools/miri/tests/fail/abort-terminator.rs
new file mode 100644
index 000000000000..c954443a2762
--- /dev/null
+++ b/src/tools/miri/tests/fail/abort-terminator.rs
@@ -0,0 +1,10 @@
+#![feature(c_unwind)]
+
+extern "C" fn panic_abort() {
+    //~^ ERROR: the program aborted
+    panic!()
+}
+
+fn main() {
+    panic_abort();
+}
diff --git a/src/tools/miri/tests/fail/abort-terminator.stderr b/src/tools/miri/tests/fail/abort-terminator.stderr
new file mode 100644
index 000000000000..ec9ce76685b5
--- /dev/null
+++ b/src/tools/miri/tests/fail/abort-terminator.stderr
@@ -0,0 +1,22 @@
+thread 'main' panicked at 'explicit panic', $DIR/abort-terminator.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> $DIR/abort-terminator.rs:LL:CC
+   |
+LL | / extern "C" fn panic_abort() {
+LL | |
+LL | |     panic!()
+LL | | }
+   | |_^ the program aborted execution
+   |
+   = note: inside `panic_abort` at $DIR/abort-terminator.rs:LL:CC
+note: inside `main` at $DIR/abort-terminator.rs:LL:CC
+  --> $DIR/abort-terminator.rs:LL:CC
+   |
+LL |     panic_abort();
+   |     ^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.rs b/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.rs
new file mode 100644
index 000000000000..a07d8254ad3d
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.rs
@@ -0,0 +1,10 @@
+use std::alloc::{alloc, dealloc, Layout};
+
+//@error-pattern: has size 1 and alignment 1, but gave size 1 and alignment 2
+
+fn main() {
+    unsafe {
+        let x = alloc(Layout::from_size_align_unchecked(1, 1));
+        dealloc(x, Layout::from_size_align_unchecked(1, 2));
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.stderr b/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.stderr
new file mode 100644
index 000000000000..28439b54b290
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 1 and alignment ALIGN
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 1 and alignment ALIGN
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+note: inside `main` at $DIR/deallocate-bad-alignment.rs:LL:CC
+  --> $DIR/deallocate-bad-alignment.rs:LL:CC
+   |
+LL |         dealloc(x, Layout::from_size_align_unchecked(1, 2));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-bad-size.rs b/src/tools/miri/tests/fail/alloc/deallocate-bad-size.rs
new file mode 100644
index 000000000000..47aaef1935e9
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-bad-size.rs
@@ -0,0 +1,10 @@
+use std::alloc::{alloc, dealloc, Layout};
+
+//@error-pattern: has size 1 and alignment 1, but gave size 2 and alignment 1
+
+fn main() {
+    unsafe {
+        let x = alloc(Layout::from_size_align_unchecked(1, 1));
+        dealloc(x, Layout::from_size_align_unchecked(2, 1));
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-bad-size.stderr b/src/tools/miri/tests/fail/alloc/deallocate-bad-size.stderr
new file mode 100644
index 000000000000..a6ceab1f56f5
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-bad-size.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+note: inside `main` at $DIR/deallocate-bad-size.rs:LL:CC
+  --> $DIR/deallocate-bad-size.rs:LL:CC
+   |
+LL |         dealloc(x, Layout::from_size_align_unchecked(2, 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-twice.rs b/src/tools/miri/tests/fail/alloc/deallocate-twice.rs
new file mode 100644
index 000000000000..1eb9bbf91ca5
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-twice.rs
@@ -0,0 +1,11 @@
+use std::alloc::{alloc, dealloc, Layout};
+
+//@error-pattern: dereferenced after this allocation got freed
+
+fn main() {
+    unsafe {
+        let x = alloc(Layout::from_size_align_unchecked(1, 1));
+        dealloc(x, Layout::from_size_align_unchecked(1, 1));
+        dealloc(x, Layout::from_size_align_unchecked(1, 1));
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr b/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr
new file mode 100644
index 000000000000..b6c5b6f97ee7
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+note: inside `main` at $DIR/deallocate-twice.rs:LL:CC
+  --> $DIR/deallocate-twice.rs:LL:CC
+   |
+LL |         dealloc(x, Layout::from_size_align_unchecked(1, 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/global_system_mixup.rs b/src/tools/miri/tests/fail/alloc/global_system_mixup.rs
new file mode 100644
index 000000000000..47b098c71a2b
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/global_system_mixup.rs
@@ -0,0 +1,19 @@
+// Make sure we detect when the `Global` and `System` allocators are mixed
+// (even when the default `Global` uses `System`).
+//@error-pattern: /deallocating .*, which is Rust heap memory, using .* heap deallocation operation/
+
+//@normalize-stderr-test: "using [A-Za-z]+ heap deallocation operation" -> "using PLATFORM heap deallocation operation"
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "libc::free\([^()]*\)|unsafe \{ HeapFree\([^()]*\) \};" -> "FREE();"
+
+#![feature(allocator_api, slice_ptr_get)]
+
+use std::alloc::{Allocator, Global, Layout, System};
+
+fn main() {
+    let l = Layout::from_size_align(1, 1).unwrap();
+    let ptr = Global.allocate(l).unwrap().as_non_null_ptr();
+    unsafe {
+        System.deallocate(ptr, l);
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/global_system_mixup.stderr b/src/tools/miri/tests/fail/alloc/global_system_mixup.stderr
new file mode 100644
index 000000000000..4ee85add6c22
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/global_system_mixup.stderr
@@ -0,0 +1,21 @@
+error: Undefined Behavior: deallocating ALLOC, which is Rust heap memory, using PLATFORM heap deallocation operation
+  --> RUSTLIB/std/src/sys/PLATFORM/alloc.rs:LL:CC
+   |
+LL |         FREE();
+   | ^ deallocating ALLOC, which is Rust heap memory, using PLATFORM heap deallocation operation
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::sys::PLATFORM::alloc::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/PLATFORM/alloc.rs:LL:CC
+   = note: inside `<std::alloc::System as std::alloc::Allocator>::deallocate` at RUSTLIB/std/src/alloc.rs:LL:CC
+note: inside `main` at $DIR/global_system_mixup.rs:LL:CC
+  --> $DIR/global_system_mixup.rs:LL:CC
+   |
+LL |         System.deallocate(ptr, l);
+   | ^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/no_global_allocator.rs b/src/tools/miri/tests/fail/alloc/no_global_allocator.rs
new file mode 100644
index 000000000000..fb0e7986bb5e
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/no_global_allocator.rs
@@ -0,0 +1,25 @@
+// Make sure we pretend the allocation symbols don't exist when there is no allocator
+
+#![feature(lang_items, start)]
+#![no_std]
+
+extern "Rust" {
+    fn __rust_alloc(size: usize, align: usize) -> *mut u8;
+}
+
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
+    unsafe {
+        __rust_alloc(1, 1); //~ERROR: unsupported operation: can't call foreign function: __rust_alloc
+    }
+
+    0
+}
+
+#[panic_handler]
+fn panic_handler(_: &core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+#[lang = "eh_personality"]
+fn eh_personality() {}
diff --git a/src/tools/miri/tests/fail/alloc/no_global_allocator.stderr b/src/tools/miri/tests/fail/alloc/no_global_allocator.stderr
new file mode 100644
index 000000000000..ea70970ae0fe
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/no_global_allocator.stderr
@@ -0,0 +1,12 @@
+error: unsupported operation: can't call foreign function: __rust_alloc
+  --> $DIR/no_global_allocator.rs:LL:CC
+   |
+LL |         __rust_alloc(1, 1);
+   |         ^^^^^^^^^^^^^^^^^^ can't call foreign function: __rust_alloc
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `start` at $DIR/no_global_allocator.rs:LL:CC
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-bad-size.rs b/src/tools/miri/tests/fail/alloc/reallocate-bad-size.rs
new file mode 100644
index 000000000000..145c3393d677
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/reallocate-bad-size.rs
@@ -0,0 +1,10 @@
+use std::alloc::{alloc, realloc, Layout};
+
+//@error-pattern: has size 1 and alignment 1, but gave size 2 and alignment 1
+
+fn main() {
+    unsafe {
+        let x = alloc(Layout::from_size_align_unchecked(1, 1));
+        let _y = realloc(x, Layout::from_size_align_unchecked(2, 1), 1);
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr b/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr
new file mode 100644
index 000000000000..c11b5a851048
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_realloc(ptr, layout.size(), layout.align(), new_size) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::realloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+note: inside `main` at $DIR/reallocate-bad-size.rs:LL:CC
+  --> $DIR/reallocate-bad-size.rs:LL:CC
+   |
+LL |         let _y = realloc(x, Layout::from_size_align_unchecked(2, 1), 1);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-change-alloc.rs b/src/tools/miri/tests/fail/alloc/reallocate-change-alloc.rs
new file mode 100644
index 000000000000..3ad56da2c2ff
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/reallocate-change-alloc.rs
@@ -0,0 +1,9 @@
+use std::alloc::{alloc, realloc, Layout};
+
+fn main() {
+    unsafe {
+        let x = alloc(Layout::from_size_align_unchecked(1, 1));
+        let _y = realloc(x, Layout::from_size_align_unchecked(1, 1), 1);
+        let _z = *x; //~ ERROR: dereferenced after this allocation got freed
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-change-alloc.stderr b/src/tools/miri/tests/fail/alloc/reallocate-change-alloc.stderr
new file mode 100644
index 000000000000..5631dcb4cc08
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/reallocate-change-alloc.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/reallocate-change-alloc.rs:LL:CC
+   |
+LL |         let _z = *x;
+   |                  ^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/reallocate-change-alloc.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-dangling.rs b/src/tools/miri/tests/fail/alloc/reallocate-dangling.rs
new file mode 100644
index 000000000000..34f1658344a5
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/reallocate-dangling.rs
@@ -0,0 +1,11 @@
+use std::alloc::{alloc, dealloc, realloc, Layout};
+
+//@error-pattern: dereferenced after this allocation got freed
+
+fn main() {
+    unsafe {
+        let x = alloc(Layout::from_size_align_unchecked(1, 1));
+        dealloc(x, Layout::from_size_align_unchecked(1, 1));
+        let _z = realloc(x, Layout::from_size_align_unchecked(1, 1), 1);
+    }
+}
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr b/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr
new file mode 100644
index 000000000000..c7db5a729048
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_realloc(ptr, layout.size(), layout.align(), new_size) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::realloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+note: inside `main` at $DIR/reallocate-dangling.rs:LL:CC
+  --> $DIR/reallocate-dangling.rs:LL:CC
+   |
+LL |         let _z = realloc(x, Layout::from_size_align_unchecked(1, 1), 1);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/stack_free.rs b/src/tools/miri/tests/fail/alloc/stack_free.rs
new file mode 100644
index 000000000000..baf53decc441
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/stack_free.rs
@@ -0,0 +1,10 @@
+// Validation/SB changes why we fail
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+//@error-pattern: /deallocating .*, which is stack variable memory, using Rust heap deallocation operation/
+
+fn main() {
+    let x = 42;
+    let bad_box = unsafe { std::mem::transmute::<&i32, Box<i32>>(&x) };
+    drop(bad_box);
+}
diff --git a/src/tools/miri/tests/fail/alloc/stack_free.stderr b/src/tools/miri/tests/fail/alloc/stack_free.stderr
new file mode 100644
index 000000000000..44991542b135
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/stack_free.stderr
@@ -0,0 +1,24 @@
+error: Undefined Behavior: deallocating ALLOC, which is stack variable memory, using Rust heap deallocation operation
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating ALLOC, which is stack variable memory, using Rust heap deallocation operation
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `<std::alloc::Global as std::alloc::Allocator>::deallocate` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `alloc::alloc::box_free::<i32, std::alloc::Global>` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
+note: inside `main` at $DIR/stack_free.rs:LL:CC
+  --> $DIR/stack_free.rs:LL:CC
+   |
+LL |     drop(bad_box);
+   |     ^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/box-cell-alias.rs b/src/tools/miri/tests/fail/box-cell-alias.rs
new file mode 100644
index 000000000000..1a4a3b97ea3f
--- /dev/null
+++ b/src/tools/miri/tests/fail/box-cell-alias.rs
@@ -0,0 +1,18 @@
+//@compile-flags: -Zmiri-strict-provenance
+
+// Taken from <https://github.com/rust-lang/unsafe-code-guidelines/issues/194#issuecomment-520934222>.
+
+use std::cell::Cell;
+
+fn helper(val: Box<Cell<u8>>, ptr: *const Cell<u8>) -> u8 {
+    val.set(10);
+    unsafe { (*ptr).set(20) }; //~ ERROR: does not exist in the borrow stack
+    val.get()
+}
+
+fn main() {
+    let val: Box<Cell<u8>> = Box::new(Cell::new(25));
+    let ptr: *const Cell<u8> = &*val;
+    let res = helper(val, ptr);
+    assert_eq!(res, 20);
+}
diff --git a/src/tools/miri/tests/fail/box-cell-alias.stderr b/src/tools/miri/tests/fail/box-cell-alias.stderr
new file mode 100644
index 000000000000..837016399768
--- /dev/null
+++ b/src/tools/miri/tests/fail/box-cell-alias.stderr
@@ -0,0 +1,33 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/box-cell-alias.rs:LL:CC
+   |
+LL |     unsafe { (*ptr).set(20) };
+   |              ^^^^^^^^^^^^^^
+   |              |
+   |              trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |              this error occurs as part of retag at ALLOC[0x0..0x1]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x1]
+  --> $DIR/box-cell-alias.rs:LL:CC
+   |
+LL |     let ptr: *const Cell<u8> = &*val;
+   |                                ^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x1] by a Unique retag
+  --> $DIR/box-cell-alias.rs:LL:CC
+   |
+LL |     let res = helper(val, ptr);
+   |                      ^^^
+   = note: BACKTRACE:
+   = note: inside `helper` at $DIR/box-cell-alias.rs:LL:CC
+note: inside `main` at $DIR/box-cell-alias.rs:LL:CC
+  --> $DIR/box-cell-alias.rs:LL:CC
+   |
+LL |     let res = helper(val, ptr);
+   |               ^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/branchless-select-i128-pointer.rs b/src/tools/miri/tests/fail/branchless-select-i128-pointer.rs
new file mode 100644
index 000000000000..2b861e5447b0
--- /dev/null
+++ b/src/tools/miri/tests/fail/branchless-select-i128-pointer.rs
@@ -0,0 +1,22 @@
+use std::mem::transmute;
+
+#[cfg(target_pointer_width = "32")]
+type TwoPtrs = i64;
+#[cfg(target_pointer_width = "64")]
+type TwoPtrs = i128;
+
+fn main() {
+    for &my_bool in &[true, false] {
+        let mask = -(my_bool as TwoPtrs); // false -> 0, true -> -1 aka !0
+        // This is branchless code to select one or the other pointer.
+        // However, it drops provenance when transmuting to TwoPtrs, so this is UB.
+        let val = unsafe {
+            transmute::<_, &str>(
+                //~^ ERROR: constructing invalid value: encountered a dangling reference
+                !mask & transmute::<_, TwoPtrs>("false !")
+                    | mask & transmute::<_, TwoPtrs>("true !"),
+            )
+        };
+        println!("{}", val);
+    }
+}
diff --git a/src/tools/miri/tests/fail/branchless-select-i128-pointer.stderr b/src/tools/miri/tests/fail/branchless-select-i128-pointer.stderr
new file mode 100644
index 000000000000..96f2ff3282c8
--- /dev/null
+++ b/src/tools/miri/tests/fail/branchless-select-i128-pointer.stderr
@@ -0,0 +1,19 @@
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (address $HEX is unallocated)
+  --> $DIR/branchless-select-i128-pointer.rs:LL:CC
+   |
+LL | /             transmute::<_, &str>(
+LL | |
+LL | |                 !mask & transmute::<_, TwoPtrs>("false !")
+LL | |                     | mask & transmute::<_, TwoPtrs>("true !"),
+LL | |             )
+   | |_____________^ constructing invalid value: encountered a dangling reference (address $HEX is unallocated)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/branchless-select-i128-pointer.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/breakpoint.rs b/src/tools/miri/tests/fail/breakpoint.rs
new file mode 100644
index 000000000000..fb1d4d958ee6
--- /dev/null
+++ b/src/tools/miri/tests/fail/breakpoint.rs
@@ -0,0 +1,7 @@
+#![feature(core_intrinsics)]
+
+fn main() {
+    unsafe {
+        core::intrinsics::breakpoint() //~ ERROR: Trace/breakpoint trap
+    };
+}
diff --git a/src/tools/miri/tests/fail/breakpoint.stderr b/src/tools/miri/tests/fail/breakpoint.stderr
new file mode 100644
index 000000000000..7b9bbdb38289
--- /dev/null
+++ b/src/tools/miri/tests/fail/breakpoint.stderr
@@ -0,0 +1,12 @@
+error: abnormal termination: Trace/breakpoint trap
+  --> $DIR/breakpoint.rs:LL:CC
+   |
+LL |         core::intrinsics::breakpoint()
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Trace/breakpoint trap
+   |
+   = note: inside `main` at $DIR/breakpoint.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_create_main_terminate.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_main_terminate.rs
new file mode 100644
index 000000000000..065ad2d725f8
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_main_terminate.rs
@@ -0,0 +1,19 @@
+//@ignore-target-windows: No libc on Windows
+//@error-pattern: the main thread terminated without waiting for all remaining threads
+
+// Check that we terminate the program when the main thread terminates.
+
+use std::{mem, ptr};
+
+extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+    loop {}
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_create_main_terminate.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_main_terminate.stderr
new file mode 100644
index 000000000000..c5093c0e6011
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_main_terminate.stderr
@@ -0,0 +1,6 @@
+error: the main thread terminated without waiting for all remaining threads
+
+note: pass `-Zmiri-ignore-leaks` to disable this check
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_few_args.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_few_args.rs
new file mode 100644
index 000000000000..e1d3704af7c0
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_few_args.rs
@@ -0,0 +1,22 @@
+//@ignore-target-windows: No libc on Windows
+
+//! The thread function must have exactly one argument.
+
+use std::{mem, ptr};
+
+extern "C" fn thread_start() -> *mut libc::c_void {
+    panic!() //~ ERROR: callee has fewer arguments than expected
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        let thread_start: extern "C" fn() -> *mut libc::c_void = thread_start;
+        let thread_start: extern "C" fn(*mut libc::c_void) -> *mut libc::c_void =
+            mem::transmute(thread_start);
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_few_args.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_few_args.stderr
new file mode 100644
index 000000000000..94463bef8f0f
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_few_args.stderr
@@ -0,0 +1,14 @@
+error: Undefined Behavior: callee has fewer arguments than expected
+  --> $DIR/libc_pthread_create_too_few_args.rs:LL:CC
+   |
+LL |     panic!()
+   |     ^^^^^^^^ callee has fewer arguments than expected
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `thread_start` at RUSTLIB/std/src/panic.rs:LL:CC
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_many_args.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_many_args.rs
new file mode 100644
index 000000000000..7408634db528
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_many_args.rs
@@ -0,0 +1,22 @@
+//@ignore-target-windows: No libc on Windows
+
+//! The thread function must have exactly one argument.
+
+use std::{mem, ptr};
+
+extern "C" fn thread_start(_null: *mut libc::c_void, _x: i32) -> *mut libc::c_void {
+    panic!() //~ ERROR: callee has more arguments than expected
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        let thread_start: extern "C" fn(*mut libc::c_void, i32) -> *mut libc::c_void = thread_start;
+        let thread_start: extern "C" fn(*mut libc::c_void) -> *mut libc::c_void =
+            mem::transmute(thread_start);
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_many_args.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_many_args.stderr
new file mode 100644
index 000000000000..fdbe91cc8a80
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_create_too_many_args.stderr
@@ -0,0 +1,14 @@
+error: Undefined Behavior: callee has more arguments than expected
+  --> $DIR/libc_pthread_create_too_many_args.rs:LL:CC
+   |
+LL |     panic!()
+   |     ^^^^^^^^ callee has more arguments than expected
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `thread_start` at RUSTLIB/std/src/panic.rs:LL:CC
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_detached.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_detached.rs
new file mode 100644
index 000000000000..0b810dc8c721
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_detached.rs
@@ -0,0 +1,20 @@
+//@ignore-target-windows: No libc on Windows
+
+// Joining a detached thread is undefined behavior.
+
+use std::{mem, ptr};
+
+extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+    ptr::null_mut()
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_detach(native), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join a detached thread
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_detached.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_detached.stderr
new file mode 100644
index 000000000000..763e0d3665d8
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_detached.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to join a detached thread
+  --> $DIR/libc_pthread_join_detached.rs:LL:CC
+   |
+LL |         assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join a detached thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_join_detached.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_joined.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_joined.rs
new file mode 100644
index 000000000000..04ca4bbb3f61
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_joined.rs
@@ -0,0 +1,20 @@
+//@ignore-target-windows: No libc on Windows
+
+// Joining an already joined thread is undefined behavior.
+
+use std::{mem, ptr};
+
+extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+    ptr::null_mut()
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join an already joined thread
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_joined.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_joined.stderr
new file mode 100644
index 000000000000..a3253e2ef933
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_joined.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to join an already joined thread
+  --> $DIR/libc_pthread_join_joined.rs:LL:CC
+   |
+LL |         assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join an already joined thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_join_joined.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_main.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_main.rs
new file mode 100644
index 000000000000..757651821637
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_main.rs
@@ -0,0 +1,16 @@
+//@ignore-target-windows: No libc on Windows
+
+// Joining the main thread is undefined behavior.
+
+use std::{ptr, thread};
+
+fn main() {
+    let thread_id: libc::pthread_t = unsafe { libc::pthread_self() };
+    let handle = thread::spawn(move || {
+        unsafe {
+            assert_eq!(libc::pthread_join(thread_id, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join a detached thread
+        }
+    });
+    thread::yield_now();
+    handle.join().unwrap();
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_main.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_main.stderr
new file mode 100644
index 000000000000..09e14d46a967
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_main.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to join a detached thread
+  --> $DIR/libc_pthread_join_main.rs:LL:CC
+   |
+LL |             assert_eq!(libc::pthread_join(thread_id, ptr::null_mut()), 0);
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join a detached thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/libc_pthread_join_main.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_multiple.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_multiple.rs
new file mode 100644
index 000000000000..966f416eeac7
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_multiple.rs
@@ -0,0 +1,29 @@
+//@ignore-target-windows: No libc on Windows
+
+// Joining the same thread from multiple threads is undefined behavior.
+
+use std::thread;
+use std::{mem, ptr};
+
+extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+    // Yield the thread several times so that other threads can join it.
+    thread::yield_now();
+    thread::yield_now();
+    ptr::null_mut()
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        let mut native_copy: libc::pthread_t = mem::zeroed();
+        ptr::copy_nonoverlapping(&native, &mut native_copy, 1);
+        let handle = thread::spawn(move || {
+            assert_eq!(libc::pthread_join(native_copy, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join an already joined thread
+        });
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+        handle.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_multiple.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_multiple.stderr
new file mode 100644
index 000000000000..db5d7bfd5dae
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_multiple.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to join an already joined thread
+  --> $DIR/libc_pthread_join_multiple.rs:LL:CC
+   |
+LL | ...   assert_eq!(libc::pthread_join(native_copy, ptr::null_mut()), 0);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join an already joined thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/libc_pthread_join_multiple.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_self.rs b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_self.rs
new file mode 100644
index 000000000000..0c25c690f372
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_self.rs
@@ -0,0 +1,18 @@
+//@ignore-target-windows: No libc on Windows
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+// Joining itself is undefined behavior.
+
+use std::{ptr, thread};
+
+fn main() {
+    let handle = thread::spawn(|| {
+        unsafe {
+            let native: libc::pthread_t = libc::pthread_self();
+            assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0); //~ ERROR: Undefined Behavior: trying to join itself
+        }
+    });
+    thread::yield_now();
+    handle.join().unwrap();
+}
diff --git a/src/tools/miri/tests/fail/concurrency/libc_pthread_join_self.stderr b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_self.stderr
new file mode 100644
index 000000000000..8db4a83f9ceb
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/libc_pthread_join_self.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to join itself
+  --> $DIR/libc_pthread_join_self.rs:LL:CC
+   |
+LL |             assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join itself
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/libc_pthread_join_self.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/read_only_atomic_cmpxchg.rs b/src/tools/miri/tests/fail/concurrency/read_only_atomic_cmpxchg.rs
new file mode 100644
index 000000000000..cb6aeea665d3
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/read_only_atomic_cmpxchg.rs
@@ -0,0 +1,11 @@
+// Should not rely on the aliasing model for its failure.
+//@compile-flags: -Zmiri-disable-stacked-borrows
+
+use std::sync::atomic::{AtomicI32, Ordering};
+
+fn main() {
+    static X: i32 = 0;
+    let x = &X as *const i32 as *const AtomicI32;
+    let x = unsafe { &*x };
+    x.compare_exchange(1, 2, Ordering::Relaxed, Ordering::Relaxed).unwrap_err(); //~ERROR: atomic operations cannot be performed on read-only memory
+}
diff --git a/src/tools/miri/tests/fail/concurrency/read_only_atomic_cmpxchg.stderr b/src/tools/miri/tests/fail/concurrency/read_only_atomic_cmpxchg.stderr
new file mode 100644
index 000000000000..d51fdee0b256
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/read_only_atomic_cmpxchg.stderr
@@ -0,0 +1,21 @@
+error: Undefined Behavior: atomic operations cannot be performed on read-only memory
+       many platforms require atomic read-modify-write instructions to be performed on writeable memory, even if the operation fails (and is hence nominally read-only)
+       some platforms implement (some) atomic loads via compare-exchange, which means they do not work on read-only memory; it is possible that we could have an exception permitting this for specific kinds of loads
+       please report an issue at <https://github.com/rust-lang/miri/issues> if this is a problem for you
+  --> $DIR/read_only_atomic_cmpxchg.rs:LL:CC
+   |
+LL |     x.compare_exchange(1, 2, Ordering::Relaxed, Ordering::Relaxed).unwrap_err();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ atomic operations cannot be performed on read-only memory
+many platforms require atomic read-modify-write instructions to be performed on writeable memory, even if the operation fails (and is hence nominally read-only)
+some platforms implement (some) atomic loads via compare-exchange, which means they do not work on read-only memory; it is possible that we could have an exception permitting this for specific kinds of loads
+please report an issue at <https://github.com/rust-lang/miri/issues> if this is a problem for you
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/read_only_atomic_cmpxchg.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/read_only_atomic_load.rs b/src/tools/miri/tests/fail/concurrency/read_only_atomic_load.rs
new file mode 100644
index 000000000000..6e92453e3c19
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/read_only_atomic_load.rs
@@ -0,0 +1,13 @@
+// Should not rely on the aliasing model for its failure.
+//@compile-flags: -Zmiri-disable-stacked-borrows
+
+use std::sync::atomic::{AtomicI32, Ordering};
+
+fn main() {
+    static X: i32 = 0;
+    let x = &X as *const i32 as *const AtomicI32;
+    let x = unsafe { &*x };
+    // Some targets can implement atomic loads via compare_exchange, so we cannot allow them on
+    // read-only memory.
+    x.load(Ordering::Relaxed); //~ERROR: atomic operations cannot be performed on read-only memory
+}
diff --git a/src/tools/miri/tests/fail/concurrency/read_only_atomic_load.stderr b/src/tools/miri/tests/fail/concurrency/read_only_atomic_load.stderr
new file mode 100644
index 000000000000..17851d6b470b
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/read_only_atomic_load.stderr
@@ -0,0 +1,21 @@
+error: Undefined Behavior: atomic operations cannot be performed on read-only memory
+       many platforms require atomic read-modify-write instructions to be performed on writeable memory, even if the operation fails (and is hence nominally read-only)
+       some platforms implement (some) atomic loads via compare-exchange, which means they do not work on read-only memory; it is possible that we could have an exception permitting this for specific kinds of loads
+       please report an issue at <https://github.com/rust-lang/miri/issues> if this is a problem for you
+  --> $DIR/read_only_atomic_load.rs:LL:CC
+   |
+LL |     x.load(Ordering::Relaxed);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ atomic operations cannot be performed on read-only memory
+many platforms require atomic read-modify-write instructions to be performed on writeable memory, even if the operation fails (and is hence nominally read-only)
+some platforms implement (some) atomic loads via compare-exchange, which means they do not work on read-only memory; it is possible that we could have an exception permitting this for specific kinds of loads
+please report an issue at <https://github.com/rust-lang/miri/issues> if this is a problem for you
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/read_only_atomic_load.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/thread_local_static_dealloc.rs b/src/tools/miri/tests/fail/concurrency/thread_local_static_dealloc.rs
new file mode 100644
index 000000000000..d89c670b632e
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/thread_local_static_dealloc.rs
@@ -0,0 +1,16 @@
+//! Ensure that thread-local statics get deallocated when the thread dies.
+
+#![feature(thread_local)]
+
+#[thread_local]
+static mut TLS: u8 = 0;
+
+struct SendRaw(*const u8);
+unsafe impl Send for SendRaw {}
+
+fn main() {
+    unsafe {
+        let dangling_ptr = std::thread::spawn(|| SendRaw(&TLS as *const u8)).join().unwrap();
+        let _val = *dangling_ptr.0; //~ ERROR: dereferenced after this allocation got freed
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/thread_local_static_dealloc.stderr b/src/tools/miri/tests/fail/concurrency/thread_local_static_dealloc.stderr
new file mode 100644
index 000000000000..cc3e56398781
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/thread_local_static_dealloc.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/thread_local_static_dealloc.rs:LL:CC
+   |
+LL |         let _val = *dangling_ptr.0;
+   |                    ^^^^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/thread_local_static_dealloc.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.rs b/src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.rs
new file mode 100644
index 000000000000..4704cfed0393
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.rs
@@ -0,0 +1,29 @@
+//@ignore-target-windows: No libc on Windows
+
+//@compile-flags: -Zmiri-disable-abi-check
+
+//! Unwinding past the top frame of a stack is Undefined Behavior.
+
+#![feature(c_unwind)]
+
+use std::{mem, ptr};
+
+extern "C-unwind" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+    //~^ ERROR: unwinding past the topmost frame of the stack
+    panic!()
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        // Cast to avoid inserting abort-on-unwind.
+        let thread_start: extern "C-unwind" fn(*mut libc::c_void) -> *mut libc::c_void =
+            thread_start;
+        let thread_start: extern "C" fn(*mut libc::c_void) -> *mut libc::c_void =
+            mem::transmute(thread_start);
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+    }
+}
diff --git a/src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.stderr b/src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.stderr
new file mode 100644
index 000000000000..98db33e3206b
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.stderr
@@ -0,0 +1,18 @@
+thread '<unnamed>' panicked at 'explicit panic', $DIR/unwind_top_of_stack.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: Undefined Behavior: unwinding past the topmost frame of the stack
+  --> $DIR/unwind_top_of_stack.rs:LL:CC
+   |
+LL | / extern "C-unwind" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+LL | |
+LL | |     panic!()
+LL | | }
+   | |_^ unwinding past the topmost frame of the stack
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `thread_start` at $DIR/unwind_top_of_stack.rs:LL:CC
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/windows_join_detached.rs b/src/tools/miri/tests/fail/concurrency/windows_join_detached.rs
new file mode 100644
index 000000000000..548ed63534db
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/windows_join_detached.rs
@@ -0,0 +1,21 @@
+//@only-target-windows: Uses win32 api functions
+//@error-pattern: Undefined Behavior: trying to join a detached thread
+
+// Joining a detached thread is undefined behavior.
+
+use std::os::windows::io::{AsRawHandle, RawHandle};
+use std::thread;
+
+extern "system" {
+    fn CloseHandle(handle: RawHandle) -> u32;
+}
+
+fn main() {
+    let thread = thread::spawn(|| ());
+
+    unsafe {
+        assert_ne!(CloseHandle(thread.as_raw_handle()), 0);
+    }
+
+    thread.join().unwrap();
+}
diff --git a/src/tools/miri/tests/fail/concurrency/windows_join_detached.stderr b/src/tools/miri/tests/fail/concurrency/windows_join_detached.stderr
new file mode 100644
index 000000000000..20f34cf104d6
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/windows_join_detached.stderr
@@ -0,0 +1,22 @@
+error: Undefined Behavior: trying to join a detached thread
+  --> RUSTLIB/std/src/sys/PLATFORM/thread.rs:LL:CC
+   |
+LL |         let rc = unsafe { c::WaitForSingleObject(self.handle.as_raw_handle(), c::INFINITE) };
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join a detached thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::sys::PLATFORM::thread::Thread::join` at RUSTLIB/std/src/sys/PLATFORM/thread.rs:LL:CC
+   = note: inside `std::thread::JoinInner::<'_, ()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::JoinHandle::<()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+note: inside `main` at $DIR/windows_join_detached.rs:LL:CC
+  --> $DIR/windows_join_detached.rs:LL:CC
+   |
+LL |     thread.join().unwrap();
+   |     ^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/windows_join_main.rs b/src/tools/miri/tests/fail/concurrency/windows_join_main.rs
new file mode 100644
index 000000000000..cde6d19ef25b
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/windows_join_main.rs
@@ -0,0 +1,28 @@
+//@only-target-windows: Uses win32 api functions
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+// On windows, joining main is not UB, but it will block a thread forever.
+
+use std::thread;
+
+extern "system" {
+    fn WaitForSingleObject(handle: isize, timeout: u32) -> u32;
+}
+
+const INFINITE: u32 = u32::MAX;
+
+// XXX HACK: This is how miri represents the handle for thread 0.
+// This value can be "legitimately" obtained by using `GetCurrentThread` with `DuplicateHandle`
+// but miri does not implement `DuplicateHandle` yet.
+const MAIN_THREAD: isize = (2i32 << 30) as isize;
+
+fn main() {
+    thread::spawn(|| {
+        unsafe {
+            assert_eq!(WaitForSingleObject(MAIN_THREAD, INFINITE), 0); //~ ERROR: deadlock: the evaluated program deadlocked
+        }
+    })
+    .join()
+    .unwrap();
+}
diff --git a/src/tools/miri/tests/fail/concurrency/windows_join_main.stderr b/src/tools/miri/tests/fail/concurrency/windows_join_main.stderr
new file mode 100644
index 000000000000..ff0d074fa7d2
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/windows_join_main.stderr
@@ -0,0 +1,13 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/windows_join_main.rs:LL:CC
+   |
+LL |             assert_eq!(WaitForSingleObject(MAIN_THREAD, INFINITE), 0);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program deadlocked
+   |
+   = note: inside closure at RUSTLIB/core/src/macros/mod.rs:LL:CC
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/concurrency/windows_join_self.rs b/src/tools/miri/tests/fail/concurrency/windows_join_self.rs
new file mode 100644
index 000000000000..d9bbf66a7dca
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/windows_join_self.rs
@@ -0,0 +1,25 @@
+//@only-target-windows: Uses win32 api functions
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+// On windows, a thread joining itself is not UB, but it will deadlock.
+
+use std::thread;
+
+extern "system" {
+    fn GetCurrentThread() -> usize;
+    fn WaitForSingleObject(handle: usize, timeout: u32) -> u32;
+}
+
+const INFINITE: u32 = u32::MAX;
+
+fn main() {
+    thread::spawn(|| {
+        unsafe {
+            let native = GetCurrentThread();
+            assert_eq!(WaitForSingleObject(native, INFINITE), 0); //~ ERROR: deadlock: the evaluated program deadlocked
+        }
+    })
+    .join()
+    .unwrap();
+}
diff --git a/src/tools/miri/tests/fail/concurrency/windows_join_self.stderr b/src/tools/miri/tests/fail/concurrency/windows_join_self.stderr
new file mode 100644
index 000000000000..bbec3f7257ec
--- /dev/null
+++ b/src/tools/miri/tests/fail/concurrency/windows_join_self.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/windows_join_self.rs:LL:CC
+   |
+LL |             assert_eq!(WaitForSingleObject(native, INFINITE), 0);
+   |                                                            ^ the evaluated program deadlocked
+   |
+   = note: inside closure at $DIR/windows_join_self.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/const-ub-checks.rs b/src/tools/miri/tests/fail/const-ub-checks.rs
new file mode 100644
index 000000000000..fa522c30cbd0
--- /dev/null
+++ b/src/tools/miri/tests/fail/const-ub-checks.rs
@@ -0,0 +1,11 @@
+#![feature(const_ptr_read)]
+
+const UNALIGNED_READ: () = unsafe {
+    let x = &[0u8; 4];
+    let ptr = x.as_ptr().cast::<u32>();
+    ptr.read(); //~ERROR: evaluation of constant value failed
+};
+
+fn main() {
+    let _x = UNALIGNED_READ;
+}
diff --git a/src/tools/miri/tests/fail/const-ub-checks.stderr b/src/tools/miri/tests/fail/const-ub-checks.stderr
new file mode 100644
index 000000000000..a8b7ea242b97
--- /dev/null
+++ b/src/tools/miri/tests/fail/const-ub-checks.stderr
@@ -0,0 +1,9 @@
+error[E0080]: evaluation of constant value failed
+  --> $DIR/const-ub-checks.rs:LL:CC
+   |
+LL |     ptr.read();
+   |     ^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/src/tools/miri/tests/fail/copy_half_a_pointer.rs b/src/tools/miri/tests/fail/copy_half_a_pointer.rs
new file mode 100644
index 000000000000..e1dcdda7fdfe
--- /dev/null
+++ b/src/tools/miri/tests/fail/copy_half_a_pointer.rs
@@ -0,0 +1,21 @@
+//@normalize-stderr-test: "\+0x[48]" -> "+HALF_PTR"
+#![allow(dead_code)]
+
+// We use packed structs to get around alignment restrictions
+#[repr(packed)]
+struct Data {
+    pad: u8,
+    ptr: &'static i32,
+}
+
+static G: i32 = 0;
+
+fn main() {
+    let mut d = Data { pad: 0, ptr: &G };
+
+    // Get a pointer to the beginning of the Data struct (one u8 byte, then the pointer bytes).
+    let d_alias = &mut d as *mut _ as *mut *const u8;
+    unsafe {
+        let _x = d_alias.read_unaligned(); //~ERROR: unable to copy parts of a pointer
+    }
+}
diff --git a/src/tools/miri/tests/fail/copy_half_a_pointer.stderr b/src/tools/miri/tests/fail/copy_half_a_pointer.stderr
new file mode 100644
index 000000000000..21797757084e
--- /dev/null
+++ b/src/tools/miri/tests/fail/copy_half_a_pointer.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: unable to copy parts of a pointer from memory at ALLOC+HALF_PTR
+  --> $DIR/copy_half_a_pointer.rs:LL:CC
+   |
+LL |         let _x = d_alias.read_unaligned();
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^ unable to copy parts of a pointer from memory at ALLOC+HALF_PTR
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/copy_half_a_pointer.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/crates/tokio_mvp.rs b/src/tools/miri/tests/fail/crates/tokio_mvp.rs
new file mode 100644
index 000000000000..7cb42c09a967
--- /dev/null
+++ b/src/tools/miri/tests/fail/crates/tokio_mvp.rs
@@ -0,0 +1,7 @@
+//@compile-flags: -Zmiri-disable-isolation
+//@error-pattern: can't call foreign function: epoll_create1
+//@normalize-stderr-test: "   = note: inside .*\n" -> ""
+//@only-target-linux: the errors differ too much between platforms
+
+#[tokio::main]
+async fn main() {}
diff --git a/src/tools/miri/tests/fail/crates/tokio_mvp.stderr b/src/tools/miri/tests/fail/crates/tokio_mvp.stderr
new file mode 100644
index 000000000000..016081d90adf
--- /dev/null
+++ b/src/tools/miri/tests/fail/crates/tokio_mvp.stderr
@@ -0,0 +1,19 @@
+error: unsupported operation: can't call foreign function: epoll_create1
+  --> CARGO_REGISTRY/.../epoll.rs:LL:CC
+   |
+LL |         syscall!(epoll_create1(flag)).map(|ep| Selector {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't call foreign function: epoll_create1
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+note: inside `main` at $DIR/tokio_mvp.rs:LL:CC
+  --> $DIR/tokio_mvp.rs:LL:CC
+   |
+LL | #[tokio::main]
+   | ^^^^^^^^^^^^^^
+   = note: this error originates in the macro `syscall` which comes from the expansion of the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_addr_of.rs b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_addr_of.rs
new file mode 100644
index 000000000000..4249c1cbf017
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_addr_of.rs
@@ -0,0 +1,12 @@
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+use std::ptr;
+
+fn main() {
+    let p = {
+        let b = Box::new(42);
+        &*b as *const i32
+    };
+    let x = unsafe { ptr::addr_of!(*p) }; //~ ERROR: dereferenced after this allocation got freed
+    panic!("this should never print: {:?}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_addr_of.stderr b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_addr_of.stderr
new file mode 100644
index 000000000000..5f081afe68af
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_addr_of.stderr
@@ -0,0 +1,16 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/dangling_pointer_addr_of.rs:LL:CC
+   |
+LL |     let x = unsafe { ptr::addr_of!(*p) };
+   |                      ^^^^^^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: this error originates in the macro `ptr::addr_of` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_deref.rs b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_deref.rs
new file mode 100644
index 000000000000..ad2a599b60b4
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_deref.rs
@@ -0,0 +1,11 @@
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+fn main() {
+    let p = {
+        let b = Box::new(42);
+        &*b as *const i32
+    };
+    let x = unsafe { *p }; //~ ERROR: dereferenced after this allocation got freed
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_deref.stderr b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_deref.stderr
new file mode 100644
index 000000000000..cb323818845d
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_pointer_deref.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/dangling_pointer_deref.rs:LL:CC
+   |
+LL |     let x = unsafe { *p };
+   |                      ^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_pointer_deref.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_zst_deref.rs b/src/tools/miri/tests/fail/dangling_pointers/dangling_zst_deref.rs
new file mode 100644
index 000000000000..534d7d5f42f3
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_zst_deref.rs
@@ -0,0 +1,11 @@
+// Make sure we find these even with many checks disabled.
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0 -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+fn main() {
+    let p = {
+        let b = Box::new(42);
+        &*b as *const i32 as *const ()
+    };
+    let _x = unsafe { *p }; //~ ERROR: dereferenced after this allocation got freed
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_zst_deref.stderr b/src/tools/miri/tests/fail/dangling_pointers/dangling_zst_deref.stderr
new file mode 100644
index 000000000000..02db6302a0a1
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_zst_deref.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/dangling_zst_deref.rs:LL:CC
+   |
+LL |     let _x = unsafe { *p };
+   |                       ^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_zst_deref.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/deref-invalid-ptr.rs b/src/tools/miri/tests/fail/dangling_pointers/deref-invalid-ptr.rs
new file mode 100644
index 000000000000..57e95ef19dc9
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/deref-invalid-ptr.rs
@@ -0,0 +1,7 @@
+// This should fail even without validation.
+//@compile-flags: -Zmiri-disable-validation -Zmiri-permissive-provenance
+
+fn main() {
+    let x = 16usize as *const u32;
+    let _y = unsafe { &*x as *const u32 }; //~ ERROR: is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/deref-invalid-ptr.stderr b/src/tools/miri/tests/fail/dangling_pointers/deref-invalid-ptr.stderr
new file mode 100644
index 000000000000..3e2c3903b7e4
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/deref-invalid-ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: 0x10[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/deref-invalid-ptr.rs:LL:CC
+   |
+LL |     let _y = unsafe { &*x as *const u32 };
+   |                       ^^^ dereferencing pointer failed: 0x10[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/deref-invalid-ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/deref-partially-dangling.rs b/src/tools/miri/tests/fail/dangling_pointers/deref-partially-dangling.rs
new file mode 100644
index 000000000000..27040c26dc21
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/deref-partially-dangling.rs
@@ -0,0 +1,8 @@
+// Deref a raw ptr to access a field of a large struct, where the field
+// is allocated but not the entire struct is.
+fn main() {
+    let x = (1, 13);
+    let xptr = &x as *const _ as *const (i32, i32, i32);
+    let val = unsafe { (*xptr).1 }; //~ ERROR: pointer to 12 bytes starting at offset 0 is out-of-bounds
+    assert_eq!(val, 13);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/deref-partially-dangling.stderr b/src/tools/miri/tests/fail/dangling_pointers/deref-partially-dangling.stderr
new file mode 100644
index 000000000000..fe039ef3adaf
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/deref-partially-dangling.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 8, so pointer to 12 bytes starting at offset 0 is out-of-bounds
+  --> $DIR/deref-partially-dangling.rs:LL:CC
+   |
+LL |     let val = unsafe { (*xptr).1 };
+   |                        ^^^^^^^^^ dereferencing pointer failed: ALLOC has size 8, so pointer to 12 bytes starting at offset 0 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/deref-partially-dangling.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dyn_size.rs b/src/tools/miri/tests/fail/dangling_pointers/dyn_size.rs
new file mode 100644
index 000000000000..54f353ebebeb
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dyn_size.rs
@@ -0,0 +1,13 @@
+// should find the bug even without these, but gets masked by optimizations
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows -Zmir-opt-level=0
+
+struct SliceWithHead(u8, [u8]);
+
+fn main() {
+    let buf = [0u32; 1];
+    // We craft a wide pointer `*const SliceWithHead` such that the unsized tail is only partially allocated.
+    // That should be UB, as the reference is not fully dereferencable.
+    let ptr: *const SliceWithHead = unsafe { std::mem::transmute((&buf, 4usize)) };
+    // Re-borrow that. This should be UB.
+    let _ptr = unsafe { &*ptr }; //~ ERROR: pointer to 5 bytes starting at offset 0 is out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/dyn_size.stderr b/src/tools/miri/tests/fail/dangling_pointers/dyn_size.stderr
new file mode 100644
index 000000000000..33aa6c844101
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/dyn_size.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 4, so pointer to 5 bytes starting at offset 0 is out-of-bounds
+  --> $DIR/dyn_size.rs:LL:CC
+   |
+LL |     let _ptr = unsafe { &*ptr };
+   |                         ^^^^^ dereferencing pointer failed: ALLOC has size 4, so pointer to 5 bytes starting at offset 0 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dyn_size.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_deref_zst.rs b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_deref_zst.rs
new file mode 100644
index 000000000000..a48a3189db2e
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_deref_zst.rs
@@ -0,0 +1,8 @@
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0
+
+fn main() {
+    // This pointer *could* be NULL so we cannot load from it, not even at ZST
+    let ptr = (&0u8 as *const u8).wrapping_sub(0x800) as *const ();
+    let _x: () = unsafe { *ptr }; //~ ERROR: out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_deref_zst.stderr b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_deref_zst.stderr
new file mode 100644
index 000000000000..3e492a170c8b
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_deref_zst.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 1, so pointer at offset -2048 is out-of-bounds
+  --> $DIR/maybe_null_pointer_deref_zst.rs:LL:CC
+   |
+LL |     let _x: () = unsafe { *ptr };
+   |                           ^^^^ dereferencing pointer failed: ALLOC has size 1, so pointer at offset -2048 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/maybe_null_pointer_deref_zst.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_write_zst.rs b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_write_zst.rs
new file mode 100644
index 000000000000..449c65d218a0
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_write_zst.rs
@@ -0,0 +1,11 @@
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0
+
+fn main() {
+    // This pointer *could* be NULL so we cannot load from it, not even at ZST.
+    // Not using the () type here, as writes of that type do not even have MIR generated.
+    // Also not assigning directly as that's array initialization, not assignment.
+    let zst_val = [1u8; 0];
+    let ptr = (&0u8 as *const u8).wrapping_sub(0x800) as *mut [u8; 0];
+    unsafe { *ptr = zst_val }; //~ ERROR: out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_write_zst.stderr b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_write_zst.stderr
new file mode 100644
index 000000000000..c41c20aaf4a7
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/maybe_null_pointer_write_zst.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 1, so pointer at offset -2048 is out-of-bounds
+  --> $DIR/maybe_null_pointer_write_zst.rs:LL:CC
+   |
+LL |     unsafe { *ptr = zst_val };
+   |              ^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 1, so pointer at offset -2048 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/maybe_null_pointer_write_zst.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.rs b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.rs
new file mode 100644
index 000000000000..a0773c63cf6b
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.rs
@@ -0,0 +1,5 @@
+#[allow(deref_nullptr)]
+fn main() {
+    let x: i32 = unsafe { *std::ptr::null() }; //~ ERROR: null pointer is a dangling pointer
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.stderr b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.stderr
new file mode 100644
index 000000000000..64dcaa454847
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/null_pointer_deref.rs:LL:CC
+   |
+LL |     let x: i32 = unsafe { *std::ptr::null() };
+   |                           ^^^^^^^^^^^^^^^^^ dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/null_pointer_deref.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref_zst.rs b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref_zst.rs
new file mode 100644
index 000000000000..d6a607c61cbe
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref_zst.rs
@@ -0,0 +1,8 @@
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0
+
+#[allow(deref_nullptr)]
+fn main() {
+    let x: () = unsafe { *std::ptr::null() }; //~ ERROR: dereferencing pointer failed: null pointer is a dangling pointer
+    panic!("this should never print: {:?}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref_zst.stderr b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref_zst.stderr
new file mode 100644
index 000000000000..301578a4f5fb
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref_zst.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/null_pointer_deref_zst.rs:LL:CC
+   |
+LL |     let x: () = unsafe { *std::ptr::null() };
+   |                          ^^^^^^^^^^^^^^^^^ dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/null_pointer_deref_zst.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.rs b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.rs
new file mode 100644
index 000000000000..954596f57542
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.rs
@@ -0,0 +1,4 @@
+#[allow(deref_nullptr)]
+fn main() {
+    unsafe { *std::ptr::null_mut() = 0i32 }; //~ ERROR: null pointer is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.stderr b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.stderr
new file mode 100644
index 000000000000..0e5858a96f9d
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/null_pointer_write.rs:LL:CC
+   |
+LL |     unsafe { *std::ptr::null_mut() = 0i32 };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/null_pointer_write.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write_zst.rs b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write_zst.rs
new file mode 100644
index 000000000000..c00344b6de23
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write_zst.rs
@@ -0,0 +1,11 @@
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0
+
+#[allow(deref_nullptr)]
+fn main() {
+    // Not using the () type here, as writes of that type do not even have MIR generated.
+    // Also not assigning directly as that's array initialization, not assignment.
+    let zst_val = [1u8; 0];
+    unsafe { std::ptr::null_mut::<[u8; 0]>().write(zst_val) };
+    //~^ERROR: memory access failed: null pointer is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write_zst.stderr b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write_zst.stderr
new file mode 100644
index 000000000000..2953d85c25f3
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/null_pointer_write_zst.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: memory access failed: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/null_pointer_write_zst.rs:LL:CC
+   |
+LL |     unsafe { std::ptr::null_mut::<[u8; 0]>().write(zst_val) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/null_pointer_write_zst.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read1.rs b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read1.rs
new file mode 100644
index 000000000000..58a64eecace8
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read1.rs
@@ -0,0 +1,5 @@
+fn main() {
+    let v: Vec<u8> = vec![1, 2];
+    let x = unsafe { *v.as_ptr().wrapping_offset(5) }; //~ ERROR: out-of-bounds
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read1.stderr b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read1.stderr
new file mode 100644
index 000000000000..b2461ce4230a
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
+  --> $DIR/out_of_bounds_read1.rs:LL:CC
+   |
+LL |     let x = unsafe { *v.as_ptr().wrapping_offset(5) };
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/out_of_bounds_read1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read2.rs b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read2.rs
new file mode 100644
index 000000000000..58a64eecace8
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read2.rs
@@ -0,0 +1,5 @@
+fn main() {
+    let v: Vec<u8> = vec![1, 2];
+    let x = unsafe { *v.as_ptr().wrapping_offset(5) }; //~ ERROR: out-of-bounds
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read2.stderr b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read2.stderr
new file mode 100644
index 000000000000..b17058b40629
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/out_of_bounds_read2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
+  --> $DIR/out_of_bounds_read2.rs:LL:CC
+   |
+LL |     let x = unsafe { *v.as_ptr().wrapping_offset(5) };
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 2, so pointer to 1 byte starting at offset 5 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/out_of_bounds_read2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/stack_temporary.rs b/src/tools/miri/tests/fail/dangling_pointers/stack_temporary.rs
new file mode 100644
index 000000000000..1373773f68d5
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/stack_temporary.rs
@@ -0,0 +1,14 @@
+// This should fail even without validation, but some MIR opts mask the error
+//@compile-flags: -Zmiri-disable-validation -Zmir-opt-level=0
+
+unsafe fn make_ref<'a>(x: *mut i32) -> &'a mut i32 {
+    &mut *x
+}
+
+fn main() {
+    unsafe {
+        let x = make_ref(&mut 0); // The temporary storing "0" is deallocated at the ";"!
+        let val = *x; //~ ERROR: dereferenced after this allocation got freed
+        println!("{}", val);
+    }
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/stack_temporary.stderr b/src/tools/miri/tests/fail/dangling_pointers/stack_temporary.stderr
new file mode 100644
index 000000000000..679e4809ca66
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/stack_temporary.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/stack_temporary.rs:LL:CC
+   |
+LL |         let val = *x;
+   |                   ^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/stack_temporary.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/storage_dead_dangling.rs b/src/tools/miri/tests/fail/dangling_pointers/storage_dead_dangling.rs
new file mode 100644
index 000000000000..03113585d146
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/storage_dead_dangling.rs
@@ -0,0 +1,26 @@
+// This should fail even without validation, but some MIR opts mask the error
+//@compile-flags: -Zmiri-disable-validation -Zmir-opt-level=0 -Zmiri-permissive-provenance
+
+static mut LEAK: usize = 0;
+
+fn fill(v: &mut i32) {
+    unsafe {
+        LEAK = v as *mut _ as usize;
+    }
+}
+
+fn evil() {
+    unsafe { &mut *(LEAK as *mut i32) }; //~ ERROR: is a dangling pointer
+}
+
+fn main() {
+    let _y;
+    {
+        let mut x = 0i32;
+        fill(&mut x);
+        _y = x;
+    }
+    // Now we use a pointer to `x` which is no longer in scope, and thus dead (even though the
+    // `main` stack frame still exists). We even try going through a `usize` for extra sneakiness!
+    evil();
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/storage_dead_dangling.stderr b/src/tools/miri/tests/fail/dangling_pointers/storage_dead_dangling.stderr
new file mode 100644
index 000000000000..72e5f20f924a
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/storage_dead_dangling.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/storage_dead_dangling.rs:LL:CC
+   |
+LL |     unsafe { &mut *(LEAK as *mut i32) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `evil` at $DIR/storage_dead_dangling.rs:LL:CC
+note: inside `main` at $DIR/storage_dead_dangling.rs:LL:CC
+  --> $DIR/storage_dead_dangling.rs:LL:CC
+   |
+LL |     evil();
+   |     ^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dangling_pointers/wild_pointer_deref.rs b/src/tools/miri/tests/fail/dangling_pointers/wild_pointer_deref.rs
new file mode 100644
index 000000000000..9ffc68146550
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/wild_pointer_deref.rs
@@ -0,0 +1,7 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    let p = 44 as *const i32;
+    let x = unsafe { *p }; //~ ERROR: is a dangling pointer
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/dangling_pointers/wild_pointer_deref.stderr b/src/tools/miri/tests/fail/dangling_pointers/wild_pointer_deref.stderr
new file mode 100644
index 000000000000..658fb228174e
--- /dev/null
+++ b/src/tools/miri/tests/fail/dangling_pointers/wild_pointer_deref.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: 0x2c[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/wild_pointer_deref.rs:LL:CC
+   |
+LL |     let x = unsafe { *p };
+   |                      ^^ dereferencing pointer failed: 0x2c[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/wild_pointer_deref.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/alloc_read_race.rs b/src/tools/miri/tests/fail/data_race/alloc_read_race.rs
new file mode 100644
index 000000000000..0bd3068af1ff
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/alloc_read_race.rs
@@ -0,0 +1,49 @@
+//@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+#![feature(new_uninit)]
+
+use std::mem::MaybeUninit;
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer = AtomicPtr::new(null_mut::<MaybeUninit<usize>>());
+    let ptr = EvilSend(&pointer as *const AtomicPtr<MaybeUninit<usize>>);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, otherwise the allocation is
+    // not visible to the other-thread to
+    // detect the race:
+    //  1. alloc
+    //  2. write
+    unsafe {
+        let j1 = spawn(move || {
+            // Concurrent allocate the memory.
+            // Uses relaxed semantics to not generate
+            // a release sequence.
+            let pointer = &*ptr.0;
+            pointer.store(Box::into_raw(Box::new_uninit()), Ordering::Relaxed);
+        });
+
+        let j2 = spawn(move || {
+            let pointer = &*ptr.0;
+
+            // Note: could also error due to reading uninitialized memory, but the data-race detector triggers first.
+            *pointer.load(Ordering::Relaxed) //~ ERROR: Data race detected between Read on thread `<unnamed>` and Allocate on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+
+        // Clean up memory, will never be executed
+        drop(Box::from_raw(pointer.load(Ordering::Relaxed)));
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr b/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr
new file mode 100644
index 000000000000..c6bfd12b2411
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC
+  --> $DIR/alloc_read_race.rs:LL:CC
+   |
+LL |             *pointer.load(Ordering::Relaxed)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Read on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/alloc_read_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/alloc_write_race.rs b/src/tools/miri/tests/fail/data_race/alloc_write_race.rs
new file mode 100644
index 000000000000..7991280721e2
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/alloc_write_race.rs
@@ -0,0 +1,47 @@
+//@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+#![feature(new_uninit)]
+
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer = AtomicPtr::new(null_mut::<usize>());
+    let ptr = EvilSend(&pointer as *const AtomicPtr<usize>);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, otherwise the allocation is
+    // not visible to the other-thread to
+    // detect the race:
+    //  1. alloc
+    //  2. write
+    unsafe {
+        let j1 = spawn(move || {
+            // Concurrent allocate the memory.
+            // Uses relaxed semantics to not generate
+            // a release sequence.
+            let pointer = &*ptr.0;
+            pointer
+                .store(Box::into_raw(Box::<usize>::new_uninit()) as *mut usize, Ordering::Relaxed);
+        });
+
+        let j2 = spawn(move || {
+            let pointer = &*ptr.0;
+            *pointer.load(Ordering::Relaxed) = 2; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Allocate on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+
+        // Clean up memory, will never be executed
+        drop(Box::from_raw(pointer.load(Ordering::Relaxed)));
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr b/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr
new file mode 100644
index 000000000000..c4efc175c207
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC
+  --> $DIR/alloc_write_race.rs:LL:CC
+   |
+LL |             *pointer.load(Ordering::Relaxed) = 2;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/alloc_write_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs
new file mode 100644
index 000000000000..2b0446d724a0
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs
@@ -0,0 +1,29 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = AtomicUsize::new(0);
+    let b = &mut a as *mut AtomicUsize;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *(c.0 as *mut usize) = 32;
+        });
+
+        let j2 = spawn(move || {
+            (&*c.0).load(Ordering::SeqCst) //~ ERROR: Data race detected between Atomic Load on thread `<unnamed>` and Write on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr
new file mode 100644
index 000000000000..04adf0a98b6c
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Atomic Load on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/atomic_read_na_write_race1.rs:LL:CC
+   |
+LL |             (&*c.0).load(Ordering::SeqCst)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Atomic Load on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/atomic_read_na_write_race1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs
new file mode 100644
index 000000000000..ef5157515c64
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs
@@ -0,0 +1,32 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = AtomicUsize::new(0);
+    let b = &mut a as *mut AtomicUsize;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            let atomic_ref = &mut *c.0;
+            atomic_ref.load(Ordering::SeqCst)
+        });
+
+        let j2 = spawn(move || {
+            let atomic_ref = &mut *c.0;
+            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Atomic Load on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr
new file mode 100644
index 000000000000..b48f927b8fca
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Atomic Load on thread `<unnamed>` at ALLOC
+  --> $DIR/atomic_read_na_write_race2.rs:LL:CC
+   |
+LL |             *atomic_ref.get_mut() = 32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Atomic Load on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/atomic_read_na_write_race2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs
new file mode 100644
index 000000000000..8c17e7674843
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs
@@ -0,0 +1,32 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = AtomicUsize::new(0);
+    let b = &mut a as *mut AtomicUsize;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            let atomic_ref = &mut *c.0;
+            atomic_ref.store(32, Ordering::SeqCst)
+        });
+
+        let j2 = spawn(move || {
+            let atomic_ref = &mut *c.0;
+            *atomic_ref.get_mut() //~ ERROR: Data race detected between Read on thread `<unnamed>` and Atomic Store on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr
new file mode 100644
index 000000000000..fdb9b353a67b
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC
+  --> $DIR/atomic_write_na_read_race1.rs:LL:CC
+   |
+LL |             *atomic_ref.get_mut()
+   |             ^^^^^^^^^^^^^^^^^^^^^ Data race detected between Read on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/atomic_write_na_read_race1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs
new file mode 100644
index 000000000000..f14d7c704dbb
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs
@@ -0,0 +1,29 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = AtomicUsize::new(0);
+    let b = &mut a as *mut AtomicUsize;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            let _val = *(c.0 as *mut usize);
+        });
+
+        let j2 = spawn(move || {
+            (&*c.0).store(32, Ordering::SeqCst); //~ ERROR: Data race detected between Atomic Store on thread `<unnamed>` and Read on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr
new file mode 100644
index 000000000000..ec581e322b7d
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Atomic Store on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+  --> $DIR/atomic_write_na_read_race2.rs:LL:CC
+   |
+LL |             (&*c.0).store(32, Ordering::SeqCst);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Atomic Store on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/atomic_write_na_read_race2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs
new file mode 100644
index 000000000000..0804b3340758
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs
@@ -0,0 +1,29 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = AtomicUsize::new(0);
+    let b = &mut a as *mut AtomicUsize;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *(c.0 as *mut usize) = 32;
+        });
+
+        let j2 = spawn(move || {
+            (&*c.0).store(64, Ordering::SeqCst); //~ ERROR: Data race detected between Atomic Store on thread `<unnamed>` and Write on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr
new file mode 100644
index 000000000000..4c75f94d71cf
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Atomic Store on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/atomic_write_na_write_race1.rs:LL:CC
+   |
+LL |             (&*c.0).store(64, Ordering::SeqCst);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Atomic Store on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/atomic_write_na_write_race1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs
new file mode 100644
index 000000000000..658cddcc9c5b
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs
@@ -0,0 +1,32 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = AtomicUsize::new(0);
+    let b = &mut a as *mut AtomicUsize;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            let atomic_ref = &mut *c.0;
+            atomic_ref.store(64, Ordering::SeqCst);
+        });
+
+        let j2 = spawn(move || {
+            let atomic_ref = &mut *c.0;
+            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Atomic Store on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr
new file mode 100644
index 000000000000..8c7f14081c87
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC
+  --> $DIR/atomic_write_na_write_race2.rs:LL:CC
+   |
+LL |             *atomic_ref.get_mut() = 32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/atomic_write_na_write_race2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs
new file mode 100644
index 000000000000..af2588e92324
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs
@@ -0,0 +1,42 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-preemption-rate=0
+
+use std::mem;
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    let join = unsafe {
+        spawn(move || {
+            *c.0 = 32;
+        })
+    };
+
+    // Detach the thread and sleep until it terminates
+    mem::drop(join);
+    sleep(Duration::from_millis(200));
+
+    // Spawn and immediately join a thread
+    // to execute the join code-path
+    // and ensure that data-race detection
+    // remains enabled nevertheless.
+    spawn(|| ()).join().unwrap();
+
+    let join2 = unsafe {
+        spawn(move || {
+            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+        })
+    };
+
+    join2.join().unwrap();
+}
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr
new file mode 100644
index 000000000000..663bb8d4af51
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/dangling_thread_async_race.rs:LL:CC
+   |
+LL |             *c.0 = 64;
+   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dangling_thread_async_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs b/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs
new file mode 100644
index 000000000000..1ee619c3f99d
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs
@@ -0,0 +1,38 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-preemption-rate=0
+
+use std::mem;
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    let join = unsafe {
+        spawn(move || {
+            *c.0 = 32;
+        })
+    };
+
+    // Detach the thread and sleep until it terminates
+    mem::drop(join);
+    sleep(Duration::from_millis(200));
+
+    // Spawn and immediately join a thread
+    // to execute the join code-path
+    // and ensure that data-race detection
+    // remains enabled nevertheless.
+    spawn(|| ()).join().unwrap();
+
+    unsafe {
+        *c.0 = 64; //~ ERROR: Data race detected between Write on thread `main` and Write on thread `<unnamed>`
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr b/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr
new file mode 100644
index 000000000000..ad3e1735378f
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/dangling_thread_race.rs:LL:CC
+   |
+LL |         *c.0 = 64;
+   |         ^^^^^^^^^ Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_thread_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs
new file mode 100644
index 000000000000..cbc02549a254
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs
@@ -0,0 +1,38 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+extern "Rust" {
+    fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
+}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer: *mut usize = Box::into_raw(Box::new(0usize));
+    let ptr = EvilSend(pointer);
+
+    unsafe {
+        let j1 = spawn(move || {
+            let _val = *ptr.0;
+        });
+
+        let j2 = spawn(move || {
+            __rust_dealloc(
+                //~^ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>`
+                ptr.0 as *mut _,
+                std::mem::size_of::<usize>(),
+                std::mem::align_of::<usize>(),
+            );
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
new file mode 100644
index 000000000000..194c2260baaa
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+  --> $DIR/dealloc_read_race1.rs:LL:CC
+   |
+LL | /             __rust_dealloc(
+LL | |
+LL | |                 ptr.0 as *mut _,
+LL | |                 std::mem::size_of::<usize>(),
+LL | |                 std::mem::align_of::<usize>(),
+LL | |             );
+   | |_____________^ Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dealloc_read_race1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs b/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs
new file mode 100644
index 000000000000..24cce5d6fac1
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs
@@ -0,0 +1,39 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+extern "Rust" {
+    fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
+}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer: *mut usize = Box::into_raw(Box::new(0usize));
+    let ptr = EvilSend(pointer);
+
+    unsafe {
+        let j1 = spawn(move || {
+            __rust_dealloc(
+                ptr.0 as *mut _,
+                std::mem::size_of::<usize>(),
+                std::mem::align_of::<usize>(),
+            )
+        });
+
+        let j2 = spawn(move || {
+            // Also an error of the form: Data race detected between Read on thread `<unnamed>` and Deallocate on thread `<unnamed>`
+            // but the invalid allocation is detected first.
+            *ptr.0 //~ ERROR: dereferenced after this allocation got freed
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race2.stderr b/src/tools/miri/tests/fail/data_race/dealloc_read_race2.stderr
new file mode 100644
index 000000000000..f303d57c8bd9
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/dealloc_read_race2.rs:LL:CC
+   |
+LL |             *ptr.0
+   |             ^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dealloc_read_race2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs
new file mode 100644
index 000000000000..5484370f35c1
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs
@@ -0,0 +1,49 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, Ordering};
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer = AtomicPtr::new(null_mut::<usize>());
+    let ptr = EvilSend(&pointer as *const AtomicPtr<usize>);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, otherwise the allocation is
+    // not visible to the other-thread to
+    // detect the race:
+    //  1. stack-allocate
+    //  2. read
+    //  3. stack-deallocate
+    unsafe {
+        let j1 = spawn(move || {
+            let pointer = &*ptr.0;
+            {
+                let mut stack_var = 0usize;
+
+                pointer.store(&mut stack_var as *mut _, Ordering::Release);
+
+                sleep(Duration::from_millis(200));
+
+                // Now `stack_var` gets deallocated.
+            } //~ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>`
+        });
+
+        let j2 = spawn(move || {
+            let pointer = &*ptr.0;
+            *pointer.load(Ordering::Acquire)
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr
new file mode 100644
index 000000000000..c986e912f03b
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+  --> $DIR/dealloc_read_race_stack.rs:LL:CC
+   |
+LL |             }
+   |             ^ Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dealloc_read_race_stack.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs
new file mode 100644
index 000000000000..23bf73fe8c5a
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs
@@ -0,0 +1,37 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+extern "Rust" {
+    fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
+}
+pub fn main() {
+    // Shared atomic pointer
+    let pointer: *mut usize = Box::into_raw(Box::new(0usize));
+    let ptr = EvilSend(pointer);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *ptr.0 = 2;
+        });
+
+        let j2 = spawn(move || {
+            __rust_dealloc(
+                //~^ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>`
+                ptr.0 as *mut _,
+                std::mem::size_of::<usize>(),
+                std::mem::align_of::<usize>(),
+            );
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
new file mode 100644
index 000000000000..56eb0b519c48
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/dealloc_write_race1.rs:LL:CC
+   |
+LL | /             __rust_dealloc(
+LL | |
+LL | |                 ptr.0 as *mut _,
+LL | |                 std::mem::size_of::<usize>(),
+LL | |                 std::mem::align_of::<usize>(),
+LL | |             );
+   | |_____________^ Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dealloc_write_race1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs b/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs
new file mode 100644
index 000000000000..7c8033e2335e
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs
@@ -0,0 +1,38 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+extern "Rust" {
+    fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
+}
+pub fn main() {
+    // Shared atomic pointer
+    let pointer: *mut usize = Box::into_raw(Box::new(0usize));
+    let ptr = EvilSend(pointer);
+
+    unsafe {
+        let j1 = spawn(move || {
+            __rust_dealloc(
+                ptr.0 as *mut _,
+                std::mem::size_of::<usize>(),
+                std::mem::align_of::<usize>(),
+            );
+        });
+
+        let j2 = spawn(move || {
+            // Also an error of the form: Data race detected between Write on thread `<unnamed>` and Deallocate on thread `<unnamed>`
+            // but the invalid allocation is detected first.
+            *ptr.0 = 2; //~ ERROR: dereferenced after this allocation got freed
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race2.stderr b/src/tools/miri/tests/fail/data_race/dealloc_write_race2.stderr
new file mode 100644
index 000000000000..23b8e9ade0e0
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/dealloc_write_race2.rs:LL:CC
+   |
+LL |             *ptr.0 = 2;
+   |             ^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dealloc_write_race2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs
new file mode 100644
index 000000000000..1872abfe021b
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs
@@ -0,0 +1,49 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, Ordering};
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer = AtomicPtr::new(null_mut::<usize>());
+    let ptr = EvilSend(&pointer as *const AtomicPtr<usize>);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, otherwise the allocation is
+    // not visible to the other-thread to
+    // detect the race:
+    //  1. stack-allocate
+    //  2. read
+    //  3. stack-deallocate
+    unsafe {
+        let j1 = spawn(move || {
+            let pointer = &*ptr.0;
+            {
+                let mut stack_var = 0usize;
+
+                pointer.store(&mut stack_var as *mut _, Ordering::Release);
+
+                sleep(Duration::from_millis(200));
+
+                // Now `stack_var` gets deallocated.
+            } //~ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>`
+        });
+
+        let j2 = spawn(move || {
+            let pointer = &*ptr.0;
+            *pointer.load(Ordering::Acquire) = 3;
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr
new file mode 100644
index 000000000000..7b77e2470a1a
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/dealloc_write_race_stack.rs:LL:CC
+   |
+LL |             }
+   |             ^ Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/dealloc_write_race_stack.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs
new file mode 100644
index 000000000000..c11239da7feb
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs
@@ -0,0 +1,39 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Enable and then join with multiple threads.
+    let t1 = spawn(|| ());
+    let t2 = spawn(|| ());
+    let t3 = spawn(|| ());
+    let t4 = spawn(|| ());
+    t1.join().unwrap();
+    t2.join().unwrap();
+    t3.join().unwrap();
+    t4.join().unwrap();
+
+    // Perform write-write data race detection.
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 32;
+        });
+
+        let j2 = spawn(move || {
+            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr
new file mode 100644
index 000000000000..26c07ae6962b
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/enable_after_join_to_main.rs:LL:CC
+   |
+LL |             *c.0 = 64;
+   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/enable_after_join_to_main.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/fence_after_load.rs b/src/tools/miri/tests/fail/data_race/fence_after_load.rs
new file mode 100644
index 000000000000..ae443908598f
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/fence_after_load.rs
@@ -0,0 +1,24 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-preemption-rate=0
+use std::sync::atomic::{fence, AtomicUsize, Ordering};
+use std::sync::Arc;
+use std::thread;
+use std::time::Duration;
+
+fn main() {
+    static mut V: u32 = 0;
+    let a = Arc::new(AtomicUsize::default());
+    let b = a.clone();
+    thread::spawn(move || {
+        unsafe { V = 1 }
+        b.store(1, Ordering::SeqCst);
+    });
+    thread::sleep(Duration::from_millis(100));
+    fence(Ordering::SeqCst);
+    // Imagine the other thread's actions happening here.
+    assert_eq!(a.load(Ordering::Relaxed), 1);
+    // The fence is useless, since it did not happen-after the `store` in the other thread.
+    // Hence this is a data race.
+    // Also see https://github.com/rust-lang/miri/issues/2192.
+    unsafe { V = 2 } //~ERROR: Data race detected between Write on thread `main` and Write on thread `<unnamed>`
+}
diff --git a/src/tools/miri/tests/fail/data_race/fence_after_load.stderr b/src/tools/miri/tests/fail/data_race/fence_after_load.stderr
new file mode 100644
index 000000000000..0abfe213db17
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/fence_after_load.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/fence_after_load.rs:LL:CC
+   |
+LL |     unsafe { V = 2 }
+   |              ^^^^^ Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/fence_after_load.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race.rs b/src/tools/miri/tests/fail/data_race/read_write_race.rs
new file mode 100644
index 000000000000..482dd2df7df9
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/read_write_race.rs
@@ -0,0 +1,28 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            let _val = *c.0;
+        });
+
+        let j2 = spawn(move || {
+            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race.stderr b/src/tools/miri/tests/fail/data_race/read_write_race.stderr
new file mode 100644
index 000000000000..08a19537312c
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/read_write_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+  --> $DIR/read_write_race.rs:LL:CC
+   |
+LL |             *c.0 = 64;
+   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/read_write_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs b/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs
new file mode 100644
index 000000000000..1b4932439b01
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs
@@ -0,0 +1,56 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmir-opt-level=0 -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+// Note: mir-opt-level set to 0 to prevent the read of stack_var in thread 1
+// from being optimized away and preventing the detection of the data-race.
+
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, Ordering};
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer = AtomicPtr::new(null_mut::<usize>());
+    let ptr = EvilSend(&pointer as *const AtomicPtr<usize>);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, otherwise the allocation is
+    // not visible to the other-thread to
+    // detect the race:
+    //  1. stack-allocate
+    //  2. atomic_store
+    //  3. atomic_load
+    //  4. write-value
+    //  5. read-value
+    unsafe {
+        let j1 = spawn(move || {
+            // Concurrent allocate the memory.
+            // Uses relaxed semantics to not generate
+            // a release sequence.
+            let pointer = &*ptr.0;
+
+            let mut stack_var = 0usize;
+
+            pointer.store(&mut stack_var as *mut _, Ordering::Release);
+
+            sleep(Duration::from_millis(200));
+
+            stack_var //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+        });
+
+        let j2 = spawn(move || {
+            let pointer = &*ptr.0;
+            *pointer.load(Ordering::Acquire) = 3;
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr b/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr
new file mode 100644
index 000000000000..20f137afe732
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/read_write_race_stack.rs:LL:CC
+   |
+LL |             stack_var
+   |             ^^^^^^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/read_write_race_stack.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs b/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs
new file mode 100644
index 000000000000..240b4c90eb22
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs
@@ -0,0 +1,50 @@
+//@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order:
+    //  1. store release : 1
+    //  2. load acquire : 1
+    //  3. store relaxed : 2
+    //  4. load acquire : 2
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 1 {
+                SYNC.store(2, Ordering::Relaxed);
+            }
+        });
+
+        let j3 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 2 {
+                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+            } else {
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        j3.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr b/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr
new file mode 100644
index 000000000000..6121c25db22d
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/relax_acquire_race.rs:LL:CC
+   |
+LL |                 *c.0
+   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/relax_acquire_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race.rs b/src/tools/miri/tests/fail/data_race/release_seq_race.rs
new file mode 100644
index 000000000000..5ae801278357
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race.rs
@@ -0,0 +1,54 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, the sleep operations currently
+    // force the desired ordering:
+    //  1. store release : 1
+    //  2. store relaxed : 2
+    //  3. store relaxed : 3
+    //  4. load acquire : 3
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+            sleep(Duration::from_millis(200));
+            SYNC.store(3, Ordering::Relaxed);
+        });
+
+        let j2 = spawn(move || {
+            // Blocks the acquire-release sequence
+            SYNC.store(2, Ordering::Relaxed);
+        });
+
+        let j3 = spawn(move || {
+            sleep(Duration::from_millis(500));
+            if SYNC.load(Ordering::Acquire) == 3 {
+                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+            } else {
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        j3.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race.stderr b/src/tools/miri/tests/fail/data_race/release_seq_race.stderr
new file mode 100644
index 000000000000..777bc4adadc6
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/release_seq_race.rs:LL:CC
+   |
+LL |                 *c.0
+   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/release_seq_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs
new file mode 100644
index 000000000000..63e6dc2dd71b
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs
@@ -0,0 +1,49 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, the sleep operations currently
+    // force the desired ordering:
+    //  1. store release : 1
+    //  2. store relaxed : 2
+    //  3. load acquire : 2
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+
+            // C++20 update to release sequences
+            // makes this block the release sequence
+            // despite the being on the same thread
+            // as the release store.
+            SYNC.store(2, Ordering::Relaxed);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 2 {
+                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+            } else {
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr
new file mode 100644
index 000000000000..0fcb192d920f
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/release_seq_race_same_thread.rs:LL:CC
+   |
+LL |                 *c.0
+   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/release_seq_race_same_thread.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/rmw_race.rs b/src/tools/miri/tests/fail/data_race/rmw_race.rs
new file mode 100644
index 000000000000..122780d11aa1
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/rmw_race.rs
@@ -0,0 +1,51 @@
+//@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order:
+    //  1. store release : 1
+    //  2. RMW relaxed : 1 -> 2
+    //  3. store relaxed : 3
+    //  4. load acquire : 3
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.swap(2, Ordering::Relaxed) == 1 {
+                // Blocks the acquire-release sequence
+                SYNC.store(3, Ordering::Relaxed);
+            }
+        });
+
+        let j3 = spawn(move || {
+            if SYNC.load(Ordering::Acquire) == 3 {
+                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+            } else {
+                0
+            }
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        j3.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/rmw_race.stderr b/src/tools/miri/tests/fail/data_race/rmw_race.stderr
new file mode 100644
index 000000000000..3ae6f3b84fe1
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/rmw_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/rmw_race.rs:LL:CC
+   |
+LL |                 *c.0
+   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/rmw_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/stack_pop_race.rs b/src/tools/miri/tests/fail/data_race/stack_pop_race.rs
new file mode 100644
index 000000000000..8f371a680f11
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/stack_pop_race.rs
@@ -0,0 +1,25 @@
+//@ignore-target-windows: Concurrency on Windows is not supported yet.
+//@compile-flags: -Zmiri-preemption-rate=0
+use std::thread;
+
+#[derive(Copy, Clone)]
+struct MakeSend(*const i32);
+unsafe impl Send for MakeSend {}
+
+fn main() {
+    race(0);
+}
+
+// Using an argument for the ptr to point to, since those do not get StorageDead.
+fn race(local: i32) {
+    let ptr = MakeSend(&local as *const i32);
+    thread::spawn(move || {
+        let ptr = ptr;
+        let _val = unsafe { *ptr.0 };
+    });
+    // Make the other thread go first so that it does not UAF.
+    thread::yield_now();
+    // Deallocating the local (when `main` returns)
+    // races with the read in the other thread.
+    // Make sure the error points at this function's end, not just the call site.
+} //~ERROR: Data race detected between Deallocate on thread `main` and Read on thread `<unnamed>`
diff --git a/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr b/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr
new file mode 100644
index 000000000000..5de27108ab63
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: Data race detected between Deallocate on thread `main` and Read on thread `<unnamed>` at ALLOC
+  --> $DIR/stack_pop_race.rs:LL:CC
+   |
+LL | }
+   |  ^ Data race detected between Deallocate on thread `main` and Read on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `race` at $DIR/stack_pop_race.rs:LL:CC
+note: inside `main` at $DIR/stack_pop_race.rs:LL:CC
+  --> $DIR/stack_pop_race.rs:LL:CC
+   |
+LL |     race(0);
+   |     ^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race.rs b/src/tools/miri/tests/fail/data_race/write_write_race.rs
new file mode 100644
index 000000000000..13c31c87cbba
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/write_write_race.rs
@@ -0,0 +1,28 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 32;
+        });
+
+        let j2 = spawn(move || {
+            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race.stderr b/src/tools/miri/tests/fail/data_race/write_write_race.stderr
new file mode 100644
index 000000000000..ee7072ccf5d1
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/write_write_race.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/write_write_race.rs:LL:CC
+   |
+LL |             *c.0 = 64;
+   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/write_write_race.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs b/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs
new file mode 100644
index 000000000000..731ac8b26aa7
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs
@@ -0,0 +1,56 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::ptr::null_mut;
+use std::sync::atomic::{AtomicPtr, Ordering};
+use std::thread::{sleep, spawn};
+use std::time::Duration;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    // Shared atomic pointer
+    let pointer = AtomicPtr::new(null_mut::<usize>());
+    let ptr = EvilSend(&pointer as *const AtomicPtr<usize>);
+
+    // Note: this is scheduler-dependent
+    // the operations need to occur in
+    // order, otherwise the allocation is
+    // not visible to the other-thread to
+    // detect the race:
+    //  1. stack-allocate
+    //  2. atomic_store
+    //  3. atomic_load
+    //  4. write-value
+    //  5. write-value
+    unsafe {
+        let j1 = spawn(move || {
+            // Concurrent allocate the memory.
+            // Uses relaxed semantics to not generate
+            // a release sequence.
+            let pointer = &*ptr.0;
+
+            let mut stack_var = 0usize;
+
+            pointer.store(&mut stack_var as *mut _, Ordering::Release);
+
+            sleep(Duration::from_millis(200));
+
+            stack_var = 1usize; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+
+            // read to silence errors
+            stack_var
+        });
+
+        let j2 = spawn(move || {
+            let pointer = &*ptr.0;
+            *pointer.load(Ordering::Acquire) = 3;
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr b/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr
new file mode 100644
index 000000000000..ceb473c2a4a4
--- /dev/null
+++ b/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+  --> $DIR/write_write_race_stack.rs:LL:CC
+   |
+LL |             stack_var = 1usize;
+   |             ^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/write_write_race_stack.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dyn-call-trait-mismatch.rs b/src/tools/miri/tests/fail/dyn-call-trait-mismatch.rs
new file mode 100644
index 000000000000..0e7c3dbcc040
--- /dev/null
+++ b/src/tools/miri/tests/fail/dyn-call-trait-mismatch.rs
@@ -0,0 +1,16 @@
+trait T1 {
+    fn method1(self: Box<Self>);
+}
+trait T2 {
+    fn method2(self: Box<Self>);
+}
+
+impl T1 for i32 {
+    fn method1(self: Box<Self>) {}
+}
+
+fn main() {
+    let r = Box::new(0) as Box<dyn T1>;
+    let r2: Box<dyn T2> = unsafe { std::mem::transmute(r) };
+    r2.method2(); //~ERROR: call on a pointer whose vtable does not match its type
+}
diff --git a/src/tools/miri/tests/fail/dyn-call-trait-mismatch.stderr b/src/tools/miri/tests/fail/dyn-call-trait-mismatch.stderr
new file mode 100644
index 000000000000..03272105c414
--- /dev/null
+++ b/src/tools/miri/tests/fail/dyn-call-trait-mismatch.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `dyn` call on a pointer whose vtable does not match its type
+  --> $DIR/dyn-call-trait-mismatch.rs:LL:CC
+   |
+LL |     r2.method2();
+   |     ^^^^^^^^^^^^ `dyn` call on a pointer whose vtable does not match its type
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dyn-call-trait-mismatch.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.rs b/src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.rs
new file mode 100644
index 000000000000..648ac07c43ec
--- /dev/null
+++ b/src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.rs
@@ -0,0 +1,57 @@
+#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
+
+trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
+    fn a(&self) -> i32 {
+        10
+    }
+
+    fn z(&self) -> i32 {
+        11
+    }
+
+    fn y(&self) -> i32 {
+        12
+    }
+}
+
+trait Bar: Foo {
+    fn b(&self) -> i32 {
+        20
+    }
+
+    fn w(&self) -> i32 {
+        21
+    }
+}
+
+trait Baz: Bar {
+    fn c(&self) -> i32 {
+        30
+    }
+}
+
+impl Foo for i32 {
+    fn a(&self) -> i32 {
+        100
+    }
+}
+
+impl Bar for i32 {
+    fn b(&self) -> i32 {
+        200
+    }
+}
+
+impl Baz for i32 {
+    fn c(&self) -> i32 {
+        300
+    }
+}
+
+fn main() {
+    let baz: &dyn Baz = &1;
+    let baz_fake: &dyn Bar = unsafe { std::mem::transmute(baz) };
+    let _err = baz_fake as &dyn Foo;
+    //~^ERROR: upcast on a pointer whose vtable does not match its type
+}
diff --git a/src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.stderr b/src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.stderr
new file mode 100644
index 000000000000..21870ef3733e
--- /dev/null
+++ b/src/tools/miri/tests/fail/dyn-upcast-trait-mismatch.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: upcast on a pointer whose vtable does not match its type
+  --> $DIR/dyn-upcast-trait-mismatch.rs:LL:CC
+   |
+LL |     let _err = baz_fake as &dyn Foo;
+   |                ^^^^^^^^ upcast on a pointer whose vtable does not match its type
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dyn-upcast-trait-mismatch.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/environ-gets-deallocated.rs b/src/tools/miri/tests/fail/environ-gets-deallocated.rs
new file mode 100644
index 000000000000..e4597140b844
--- /dev/null
+++ b/src/tools/miri/tests/fail/environ-gets-deallocated.rs
@@ -0,0 +1,24 @@
+//@ignore-target-windows: Windows does not have a global environ list that the program can access directly
+
+#[cfg(any(target_os = "linux", target_os = "freebsd"))]
+fn get_environ() -> *const *const u8 {
+    extern "C" {
+        static mut environ: *const *const u8;
+    }
+    unsafe { environ }
+}
+
+#[cfg(target_os = "macos")]
+fn get_environ() -> *const *const u8 {
+    extern "C" {
+        fn _NSGetEnviron() -> *mut *const *const u8;
+    }
+    unsafe { *_NSGetEnviron() }
+}
+
+fn main() {
+    let pointer = get_environ();
+    let _x = unsafe { *pointer };
+    std::env::set_var("FOO", "BAR");
+    let _y = unsafe { *pointer }; //~ ERROR: dereferenced after this allocation got freed
+}
diff --git a/src/tools/miri/tests/fail/environ-gets-deallocated.stderr b/src/tools/miri/tests/fail/environ-gets-deallocated.stderr
new file mode 100644
index 000000000000..a2d343bf8651
--- /dev/null
+++ b/src/tools/miri/tests/fail/environ-gets-deallocated.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/environ-gets-deallocated.rs:LL:CC
+   |
+LL |     let _y = unsafe { *pointer };
+   |                       ^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/environ-gets-deallocated.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/erroneous_const.rs b/src/tools/miri/tests/fail/erroneous_const.rs
new file mode 100644
index 000000000000..c35a90503593
--- /dev/null
+++ b/src/tools/miri/tests/fail/erroneous_const.rs
@@ -0,0 +1,20 @@
+//! Make sure we detect erroneous constants post-monomorphization even when they are unused.
+//! (https://github.com/rust-lang/miri/issues/1382)
+// Inlining changes the error location
+//@compile-flags: -Zmir-opt-level=0
+#![feature(never_type)]
+#![warn(warnings, const_err)]
+
+struct PrintName<T>(T);
+impl<T> PrintName<T> {
+    const VOID: ! = panic!(); //~ERROR: evaluation of `PrintName::<i32>::VOID` failed
+}
+
+fn no_codegen<T>() {
+    if false {
+        let _ = PrintName::<T>::VOID; //~ERROR: post-monomorphization error
+    }
+}
+fn main() {
+    no_codegen::<i32>();
+}
diff --git a/src/tools/miri/tests/fail/erroneous_const.stderr b/src/tools/miri/tests/fail/erroneous_const.stderr
new file mode 100644
index 000000000000..8138d69f4031
--- /dev/null
+++ b/src/tools/miri/tests/fail/erroneous_const.stderr
@@ -0,0 +1,26 @@
+error[E0080]: evaluation of `PrintName::<i32>::VOID` failed
+  --> $DIR/erroneous_const.rs:LL:CC
+   |
+LL |     const VOID: ! = panic!();
+   |                     ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/erroneous_const.rs:LL:CC
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: post-monomorphization error: referenced constant has errors
+  --> $DIR/erroneous_const.rs:LL:CC
+   |
+LL |         let _ = PrintName::<T>::VOID;
+   |                 ^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+   |
+   = note: inside `no_codegen::<i32>` at $DIR/erroneous_const.rs:LL:CC
+note: inside `main` at $DIR/erroneous_const.rs:LL:CC
+  --> $DIR/erroneous_const.rs:LL:CC
+   |
+LL |     no_codegen::<i32>();
+   |     ^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/src/tools/miri/tests/fail/erroneous_const2.rs b/src/tools/miri/tests/fail/erroneous_const2.rs
new file mode 100644
index 000000000000..6628166cfacd
--- /dev/null
+++ b/src/tools/miri/tests/fail/erroneous_const2.rs
@@ -0,0 +1,13 @@
+const X: u32 = 5;
+const Y: u32 = 6;
+const FOO: u32 = [X - Y, Y - X][(X < Y) as usize];
+//~^ERROR: any use of this value
+//~|WARN: previously accepted
+
+#[rustfmt::skip] // rustfmt bug: https://github.com/rust-lang/rustfmt/issues/5391
+fn main() {
+    println!("{}", FOO); //~ERROR: post-monomorphization error
+    //~|ERROR: evaluation of constant value failed
+    //~|ERROR: erroneous constant used
+    //~|WARN: previously accepted
+}
diff --git a/src/tools/miri/tests/fail/erroneous_const2.stderr b/src/tools/miri/tests/fail/erroneous_const2.stderr
new file mode 100644
index 000000000000..05ed8ea1c14b
--- /dev/null
+++ b/src/tools/miri/tests/fail/erroneous_const2.stderr
@@ -0,0 +1,39 @@
+error: any use of this value will cause an error
+  --> $DIR/erroneous_const2.rs:LL:CC
+   |
+LL | const FOO: u32 = [X - Y, Y - X][(X < Y) as usize];
+   | --------------    ^^^^^ attempt to compute `5_u32 - 6_u32`, which would overflow
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/erroneous_const2.rs:LL:CC
+   |
+LL |     println!("{}", FOO);
+   |                    ^^^ referenced constant has errors
+
+error: erroneous constant used
+  --> $DIR/erroneous_const2.rs:LL:CC
+   |
+LL |     println!("{}", FOO);
+   |                    ^^^ referenced constant has errors
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: post-monomorphization error: referenced constant has errors
+  --> $DIR/erroneous_const2.rs:LL:CC
+   |
+LL |     println!("{}", FOO);
+   |                    ^^^ referenced constant has errors
+   |
+   = note: inside `main` at $DIR/erroneous_const2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/src/tools/miri/tests/fail/extern_static.rs b/src/tools/miri/tests/fail/extern_static.rs
new file mode 100644
index 000000000000..f8805db8d143
--- /dev/null
+++ b/src/tools/miri/tests/fail/extern_static.rs
@@ -0,0 +1,9 @@
+//! Even referencing an unknown `extern static` already triggers an error.
+
+extern "C" {
+    static mut FOO: i32;
+}
+
+fn main() {
+    let _val = unsafe { std::ptr::addr_of!(FOO) }; //~ ERROR: is not supported by Miri
+}
diff --git a/src/tools/miri/tests/fail/extern_static.stderr b/src/tools/miri/tests/fail/extern_static.stderr
new file mode 100644
index 000000000000..fa0d55e5f678
--- /dev/null
+++ b/src/tools/miri/tests/fail/extern_static.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: `extern` static `FOO` from crate `extern_static` is not supported by Miri
+  --> $DIR/extern_static.rs:LL:CC
+   |
+LL |     let _val = unsafe { std::ptr::addr_of!(FOO) };
+   |                                            ^^^ `extern` static `FOO` from crate `extern_static` is not supported by Miri
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/extern_static.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/extern_static_in_const.rs b/src/tools/miri/tests/fail/extern_static_in_const.rs
new file mode 100644
index 000000000000..31c192bf44be
--- /dev/null
+++ b/src/tools/miri/tests/fail/extern_static_in_const.rs
@@ -0,0 +1,11 @@
+//! Even referencing an unknown `extern static` already triggers an error.
+
+extern "C" {
+    static E: [u8; 0];
+}
+
+static X: &'static [u8; 0] = unsafe { &E };
+
+fn main() {
+    let _val = X; //~ ERROR: is not supported by Miri
+}
diff --git a/src/tools/miri/tests/fail/extern_static_in_const.stderr b/src/tools/miri/tests/fail/extern_static_in_const.stderr
new file mode 100644
index 000000000000..e4ee8f1acba2
--- /dev/null
+++ b/src/tools/miri/tests/fail/extern_static_in_const.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: `extern` static `E` from crate `extern_static_in_const` is not supported by Miri
+  --> $DIR/extern_static_in_const.rs:LL:CC
+   |
+LL |     let _val = X;
+   |                ^ `extern` static `E` from crate `extern_static_in_const` is not supported by Miri
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/extern_static_in_const.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/extern_static_wrong_size.rs b/src/tools/miri/tests/fail/extern_static_wrong_size.rs
new file mode 100644
index 000000000000..17061f0e5c81
--- /dev/null
+++ b/src/tools/miri/tests/fail/extern_static_wrong_size.rs
@@ -0,0 +1,10 @@
+//@ only-target-linux: we need a specific extern supported on this target
+//@normalize-stderr-test: "[48] bytes" -> "N bytes"
+
+extern "C" {
+    static mut environ: i8;
+}
+
+fn main() {
+    let _val = unsafe { environ }; //~ ERROR: /has been declared with a size of 1 bytes and alignment of 1 bytes, but Miri emulates it via an extern static shim with a size of [48] bytes and alignment of [48] bytes/
+}
diff --git a/src/tools/miri/tests/fail/extern_static_wrong_size.stderr b/src/tools/miri/tests/fail/extern_static_wrong_size.stderr
new file mode 100644
index 000000000000..a56eba09df98
--- /dev/null
+++ b/src/tools/miri/tests/fail/extern_static_wrong_size.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: `extern` static `environ` from crate `extern_static_wrong_size` has been declared with a size of 1 bytes and alignment of 1 bytes, but Miri emulates it via an extern static shim with a size of N bytes and alignment of N bytes
+  --> $DIR/extern_static_wrong_size.rs:LL:CC
+   |
+LL |     let _val = unsafe { environ };
+   |                         ^^^^^^^ `extern` static `environ` from crate `extern_static_wrong_size` has been declared with a size of 1 bytes and alignment of 1 bytes, but Miri emulates it via an extern static shim with a size of N bytes and alignment of N bytes
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/extern_static_wrong_size.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/fast_math_both.rs b/src/tools/miri/tests/fail/fast_math_both.rs
new file mode 100644
index 000000000000..dd2787bf40f4
--- /dev/null
+++ b/src/tools/miri/tests/fail/fast_math_both.rs
@@ -0,0 +1,7 @@
+#![feature(core_intrinsics)]
+
+fn main() {
+    unsafe {
+        let _x: f32 = core::intrinsics::fsub_fast(f32::NAN, f32::NAN); //~ ERROR: `fsub_fast` intrinsic called with non-finite value as both parameters
+    }
+}
diff --git a/src/tools/miri/tests/fail/fast_math_both.stderr b/src/tools/miri/tests/fail/fast_math_both.stderr
new file mode 100644
index 000000000000..2a0759f8a3ba
--- /dev/null
+++ b/src/tools/miri/tests/fail/fast_math_both.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `fsub_fast` intrinsic called with non-finite value as both parameters
+  --> $DIR/fast_math_both.rs:LL:CC
+   |
+LL | ...: f32 = core::intrinsics::fsub_fast(f32::NAN, f32::NAN);
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `fsub_fast` intrinsic called with non-finite value as both parameters
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/fast_math_both.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/fast_math_first.rs b/src/tools/miri/tests/fail/fast_math_first.rs
new file mode 100644
index 000000000000..e495498ab286
--- /dev/null
+++ b/src/tools/miri/tests/fail/fast_math_first.rs
@@ -0,0 +1,7 @@
+#![feature(core_intrinsics)]
+
+fn main() {
+    unsafe {
+        let _x: f32 = core::intrinsics::frem_fast(f32::NAN, 3.2); //~ ERROR: `frem_fast` intrinsic called with non-finite value as first parameter
+    }
+}
diff --git a/src/tools/miri/tests/fail/fast_math_first.stderr b/src/tools/miri/tests/fail/fast_math_first.stderr
new file mode 100644
index 000000000000..766662ca14ba
--- /dev/null
+++ b/src/tools/miri/tests/fail/fast_math_first.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `frem_fast` intrinsic called with non-finite value as first parameter
+  --> $DIR/fast_math_first.rs:LL:CC
+   |
+LL | ...   let _x: f32 = core::intrinsics::frem_fast(f32::NAN, 3.2);
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `frem_fast` intrinsic called with non-finite value as first parameter
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/fast_math_first.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/fast_math_second.rs b/src/tools/miri/tests/fail/fast_math_second.rs
new file mode 100644
index 000000000000..408c461077fc
--- /dev/null
+++ b/src/tools/miri/tests/fail/fast_math_second.rs
@@ -0,0 +1,7 @@
+#![feature(core_intrinsics)]
+
+fn main() {
+    unsafe {
+        let _x: f32 = core::intrinsics::fmul_fast(3.4f32, f32::INFINITY); //~ ERROR: `fmul_fast` intrinsic called with non-finite value as second parameter
+    }
+}
diff --git a/src/tools/miri/tests/fail/fast_math_second.stderr b/src/tools/miri/tests/fail/fast_math_second.stderr
new file mode 100644
index 000000000000..ce93f9398f2c
--- /dev/null
+++ b/src/tools/miri/tests/fail/fast_math_second.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `fmul_fast` intrinsic called with non-finite value as second parameter
+  --> $DIR/fast_math_second.rs:LL:CC
+   |
+LL | ...f32 = core::intrinsics::fmul_fast(3.4f32, f32::INFINITY);
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `fmul_fast` intrinsic called with non-finite value as second parameter
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/fast_math_second.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_abi.rs b/src/tools/miri/tests/fail/function_calls/check_arg_abi.rs
new file mode 100644
index 000000000000..ffa0443ce507
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_abi.rs
@@ -0,0 +1,9 @@
+fn main() {
+    extern "Rust" {
+        fn malloc(size: usize) -> *mut std::ffi::c_void;
+    }
+
+    unsafe {
+        let _ = malloc(0); //~ ERROR: calling a function with ABI C using caller ABI Rust
+    };
+}
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_abi.stderr b/src/tools/miri/tests/fail/function_calls/check_arg_abi.stderr
new file mode 100644
index 000000000000..406ccb070bab
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_abi.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with ABI C using caller ABI Rust
+  --> $DIR/check_arg_abi.rs:LL:CC
+   |
+LL |         let _ = malloc(0);
+   |                 ^^^^^^^^^ calling a function with ABI C using caller ABI Rust
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/check_arg_abi.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_count_abort.rs b/src/tools/miri/tests/fail/function_calls/check_arg_count_abort.rs
new file mode 100644
index 000000000000..967a78bf8318
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_count_abort.rs
@@ -0,0 +1,10 @@
+fn main() {
+    extern "C" {
+        fn abort(_: i32) -> !;
+    }
+
+    unsafe {
+        abort(1);
+        //~^ ERROR: Undefined Behavior: incorrect number of arguments: got 1, expected 0
+    }
+}
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_count_abort.stderr b/src/tools/miri/tests/fail/function_calls/check_arg_count_abort.stderr
new file mode 100644
index 000000000000..d90a7e31d6ee
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_count_abort.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: incorrect number of arguments: got 1, expected 0
+  --> $DIR/check_arg_count_abort.rs:LL:CC
+   |
+LL |         abort(1);
+   |         ^^^^^^^^ incorrect number of arguments: got 1, expected 0
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/check_arg_count_abort.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_count_too_few_args.rs b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_few_args.rs
new file mode 100644
index 000000000000..223c95ffca46
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_few_args.rs
@@ -0,0 +1,9 @@
+fn main() {
+    extern "C" {
+        fn malloc() -> *mut std::ffi::c_void;
+    }
+
+    unsafe {
+        let _ = malloc(); //~ ERROR: Undefined Behavior: incorrect number of arguments: got 0, expected 1
+    };
+}
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_count_too_few_args.stderr b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_few_args.stderr
new file mode 100644
index 000000000000..9e2751a216bc
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_few_args.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: incorrect number of arguments: got 0, expected 1
+  --> $DIR/check_arg_count_too_few_args.rs:LL:CC
+   |
+LL |         let _ = malloc();
+   |                 ^^^^^^^^ incorrect number of arguments: got 0, expected 1
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/check_arg_count_too_few_args.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_count_too_many_args.rs b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_many_args.rs
new file mode 100644
index 000000000000..7ee9c40bf7a4
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_many_args.rs
@@ -0,0 +1,9 @@
+fn main() {
+    extern "C" {
+        fn malloc(_: i32, _: i32) -> *mut std::ffi::c_void;
+    }
+
+    unsafe {
+        let _ = malloc(1, 2); //~ ERROR: Undefined Behavior: incorrect number of arguments: got 2, expected 1
+    };
+}
diff --git a/src/tools/miri/tests/fail/function_calls/check_arg_count_too_many_args.stderr b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_many_args.stderr
new file mode 100644
index 000000000000..e9a38b5ae421
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_arg_count_too_many_args.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: incorrect number of arguments: got 2, expected 1
+  --> $DIR/check_arg_count_too_many_args.rs:LL:CC
+   |
+LL |         let _ = malloc(1, 2);
+   |                 ^^^^^^^^^^^^ incorrect number of arguments: got 2, expected 1
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/check_arg_count_too_many_args.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/check_callback_abi.rs b/src/tools/miri/tests/fail/function_calls/check_callback_abi.rs
new file mode 100644
index 000000000000..883d5ae8096b
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_callback_abi.rs
@@ -0,0 +1,18 @@
+#![feature(core_intrinsics)]
+
+extern "C" fn try_fn(_: *mut u8) {
+    unreachable!();
+}
+
+fn main() {
+    unsafe {
+        // Make sure we check the ABI when Miri itself invokes a function
+        // as part of a shim implementation.
+        std::intrinsics::r#try(
+            //~^ ERROR: calling a function with ABI C using caller ABI Rust
+            std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
+            std::ptr::null_mut(),
+            |_, _| unreachable!(),
+        );
+    }
+}
diff --git a/src/tools/miri/tests/fail/function_calls/check_callback_abi.stderr b/src/tools/miri/tests/fail/function_calls/check_callback_abi.stderr
new file mode 100644
index 000000000000..50afc1097974
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/check_callback_abi.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: calling a function with ABI C using caller ABI Rust
+  --> $DIR/check_callback_abi.rs:LL:CC
+   |
+LL | /         std::intrinsics::r#try(
+LL | |
+LL | |             std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
+LL | |             std::ptr::null_mut(),
+LL | |             |_, _| unreachable!(),
+LL | |         );
+   | |_________^ calling a function with ABI C using caller ABI Rust
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/check_callback_abi.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.cache.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.cache.stderr
new file mode 100644
index 000000000000..ae5c6cb72b3c
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.cache.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with calling convention Rust using calling convention C
+  --> $DIR/exported_symbol_abi_mismatch.rs:LL:CC
+   |
+LL |             foo();
+   |             ^^^^^ calling a function with calling convention Rust using calling convention C
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_abi_mismatch.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.fn_ptr.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.fn_ptr.stderr
new file mode 100644
index 000000000000..17d56793ac5c
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.fn_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with calling convention Rust using calling convention C
+  --> $DIR/exported_symbol_abi_mismatch.rs:LL:CC
+   |
+LL |         std::mem::transmute::<unsafe fn(), unsafe extern "C" fn()>(foo)();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ calling a function with calling convention Rust using calling convention C
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_abi_mismatch.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.no_cache.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.no_cache.stderr
new file mode 100644
index 000000000000..ae5c6cb72b3c
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.no_cache.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with calling convention Rust using calling convention C
+  --> $DIR/exported_symbol_abi_mismatch.rs:LL:CC
+   |
+LL |             foo();
+   |             ^^^^^ calling a function with calling convention Rust using calling convention C
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_abi_mismatch.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.rs
new file mode 100644
index 000000000000..dbf72b5b61ad
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_abi_mismatch.rs
@@ -0,0 +1,35 @@
+//@revisions: no_cache cache fn_ptr
+
+#[no_mangle]
+fn foo() {}
+
+fn main() {
+    #[cfg(any(cache, fn_ptr))]
+    extern "Rust" {
+        fn foo();
+    }
+
+    #[cfg(fn_ptr)]
+    unsafe {
+        std::mem::transmute::<unsafe fn(), unsafe extern "C" fn()>(foo)();
+        //[fn_ptr]~^ ERROR: calling a function with calling convention Rust using calling convention C
+    }
+
+    // `Instance` caching should not suppress ABI check.
+    #[cfg(cache)]
+    unsafe {
+        foo();
+    }
+
+    {
+        #[cfg_attr(any(cache, fn_ptr), allow(clashing_extern_declarations))]
+        extern "C" {
+            fn foo();
+        }
+        unsafe {
+            foo();
+            //[no_cache]~^ ERROR: calling a function with calling convention Rust using calling convention C
+            //[cache]~| ERROR: calling a function with calling convention Rust using calling convention C
+        }
+    }
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.rs
new file mode 100644
index 000000000000..5f4df7c6a1ef
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.rs
@@ -0,0 +1,15 @@
+//@compile-flags: -Zmiri-disable-abi-check
+#![feature(c_unwind)]
+
+#[no_mangle]
+extern "C-unwind" fn unwind() {
+    panic!();
+}
+
+fn main() {
+    extern "C" {
+        fn unwind();
+    }
+    unsafe { unwind() }
+    //~^ ERROR: unwinding past a stack frame that does not allow unwinding
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr
new file mode 100644
index 000000000000..7f87ec6f3bb6
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr
@@ -0,0 +1,17 @@
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind1.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
+  --> $DIR/exported_symbol_bad_unwind1.rs:LL:CC
+   |
+LL |     unsafe { unwind() }
+   |              ^^^^^^^^ unwinding past a stack frame that does not allow unwinding
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_bad_unwind1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr
new file mode 100644
index 000000000000..7d9302e3e3ad
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr
@@ -0,0 +1,23 @@
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+   |
+LL | / extern "C-unwind" fn nounwind() {
+LL | |
+LL | |
+LL | |     panic!();
+LL | | }
+   | |_^ the program aborted execution
+   |
+   = note: inside `nounwind` at $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+note: inside `main` at $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+  --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+   |
+LL |     unsafe { nounwind() }
+   |              ^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr
new file mode 100644
index 000000000000..7d9302e3e3ad
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr
@@ -0,0 +1,23 @@
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+   |
+LL | / extern "C-unwind" fn nounwind() {
+LL | |
+LL | |
+LL | |     panic!();
+LL | | }
+   | |_^ the program aborted execution
+   |
+   = note: inside `nounwind` at $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+note: inside `main` at $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+  --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+   |
+LL |     unsafe { nounwind() }
+   |              ^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr
new file mode 100644
index 000000000000..b23c05a53035
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr
@@ -0,0 +1,17 @@
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
+  --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+   |
+LL |     unsafe { nounwind() }
+   |              ^^^^^^^^^^ unwinding past a stack frame that does not allow unwinding
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.rs
new file mode 100644
index 000000000000..d9aacdb8aea4
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.rs
@@ -0,0 +1,19 @@
+//@revisions: extern_block definition both
+#![feature(rustc_attrs, c_unwind)]
+
+#[cfg_attr(any(definition, both), rustc_allocator_nounwind)]
+#[no_mangle]
+extern "C-unwind" fn nounwind() {
+    //[definition]~^ ERROR: abnormal termination: the program aborted execution
+    //[both]~^^ ERROR: abnormal termination: the program aborted execution
+    panic!();
+}
+
+fn main() {
+    extern "C-unwind" {
+        #[cfg_attr(any(extern_block, both), rustc_allocator_nounwind)]
+        fn nounwind();
+    }
+    unsafe { nounwind() }
+    //[extern_block]~^ ERROR: unwinding past a stack frame that does not allow unwinding
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_clashing.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_clashing.rs
new file mode 100644
index 000000000000..45ad412e7a55
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_clashing.rs
@@ -0,0 +1,15 @@
+#[no_mangle]
+fn foo() {}
+//~^ HELP: it's first defined here, in crate `exported_symbol_clashing`
+
+#[export_name = "foo"]
+fn bar() {}
+//~^ HELP: then it's defined here again, in crate `exported_symbol_clashing`
+
+fn main() {
+    extern "Rust" {
+        fn foo();
+    }
+    unsafe { foo() }
+    //~^ ERROR: multiple definitions of symbol `foo`
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_clashing.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_clashing.stderr
new file mode 100644
index 000000000000..8eb9fa4ff5c2
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_clashing.stderr
@@ -0,0 +1,23 @@
+error: multiple definitions of symbol `foo`
+  --> $DIR/exported_symbol_clashing.rs:LL:CC
+   |
+LL |     unsafe { foo() }
+   |              ^^^^^ multiple definitions of symbol `foo`
+   |
+help: it's first defined here, in crate `exported_symbol_clashing`
+  --> $DIR/exported_symbol_clashing.rs:LL:CC
+   |
+LL | fn foo() {}
+   | ^^^^^^^^
+help: then it's defined here again, in crate `exported_symbol_clashing`
+  --> $DIR/exported_symbol_clashing.rs:LL:CC
+   |
+LL | fn bar() {}
+   | ^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_clashing.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_shim_clashing.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_shim_clashing.rs
new file mode 100644
index 000000000000..dffae7adbb97
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_shim_clashing.rs
@@ -0,0 +1,15 @@
+#[no_mangle]
+extern "C" fn malloc(_: usize) -> *mut std::ffi::c_void {
+    //~^ HELP: the `malloc` symbol is defined here
+    unreachable!()
+}
+
+fn main() {
+    extern "C" {
+        fn malloc(_: usize) -> *mut std::ffi::c_void;
+    }
+    unsafe {
+        malloc(0);
+        //~^ ERROR: found `malloc` symbol definition that clashes with a built-in shim
+    }
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_shim_clashing.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_shim_clashing.stderr
new file mode 100644
index 000000000000..58a996e64530
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_shim_clashing.stderr
@@ -0,0 +1,21 @@
+error: found `malloc` symbol definition that clashes with a built-in shim
+  --> $DIR/exported_symbol_shim_clashing.rs:LL:CC
+   |
+LL |         malloc(0);
+   |         ^^^^^^^^^ found `malloc` symbol definition that clashes with a built-in shim
+   |
+help: the `malloc` symbol is defined here
+  --> $DIR/exported_symbol_shim_clashing.rs:LL:CC
+   |
+LL | / extern "C" fn malloc(_: usize) -> *mut std::ffi::c_void {
+LL | |
+LL | |     unreachable!()
+LL | | }
+   | |_^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_shim_clashing.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_arguments.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_arguments.rs
new file mode 100644
index 000000000000..a108944c5e43
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_arguments.rs
@@ -0,0 +1,9 @@
+#[no_mangle]
+fn foo() {}
+
+fn main() {
+    extern "Rust" {
+        fn foo(_: i32);
+    }
+    unsafe { foo(1) } //~ ERROR: calling a function with more arguments than it expected
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_arguments.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_arguments.stderr
new file mode 100644
index 000000000000..1aa13ce43895
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_arguments.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with more arguments than it expected
+  --> $DIR/exported_symbol_wrong_arguments.rs:LL:CC
+   |
+LL |     unsafe { foo(1) }
+   |              ^^^^^^ calling a function with more arguments than it expected
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_wrong_arguments.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_type.rs b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_type.rs
new file mode 100644
index 000000000000..e273e354334f
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_type.rs
@@ -0,0 +1,9 @@
+#[no_mangle]
+static FOO: () = ();
+
+fn main() {
+    extern "C" {
+        fn FOO();
+    }
+    unsafe { FOO() } //~ ERROR: attempt to call an exported symbol that is not defined as a function
+}
diff --git a/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_type.stderr b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_type.stderr
new file mode 100644
index 000000000000..abfd7a9a6c4d
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_calls/exported_symbol_wrong_type.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: attempt to call an exported symbol that is not defined as a function
+  --> $DIR/exported_symbol_wrong_type.rs:LL:CC
+   |
+LL |     unsafe { FOO() }
+   |              ^^^^^ attempt to call an exported symbol that is not defined as a function
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exported_symbol_wrong_type.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_box_int_to_fn_ptr.rs b/src/tools/miri/tests/fail/function_pointers/cast_box_int_to_fn_ptr.rs
new file mode 100644
index 000000000000..9815569b607f
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_box_int_to_fn_ptr.rs
@@ -0,0 +1,9 @@
+// Validation makes this fail in the wrong place
+//@compile-flags: -Zmiri-disable-validation
+
+fn main() {
+    let b = Box::new(42);
+    let g = unsafe { std::mem::transmute::<&Box<usize>, &fn(i32)>(&b) };
+
+    (*g)(42) //~ ERROR: it does not point to a function
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_box_int_to_fn_ptr.stderr b/src/tools/miri/tests/fail/function_pointers/cast_box_int_to_fn_ptr.stderr
new file mode 100644
index 000000000000..ad43c2c9d3fe
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_box_int_to_fn_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using ALLOC as function pointer but it does not point to a function
+  --> $DIR/cast_box_int_to_fn_ptr.rs:LL:CC
+   |
+LL |     (*g)(42)
+   |     ^^^^^^^^ using ALLOC as function pointer but it does not point to a function
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_box_int_to_fn_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr1.rs b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr1.rs
new file mode 100644
index 000000000000..c0e96a43cc52
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr1.rs
@@ -0,0 +1,7 @@
+fn main() {
+    fn f() {}
+
+    let g = unsafe { std::mem::transmute::<fn(), fn(i32)>(f) };
+
+    g(42) //~ ERROR: calling a function with more arguments than it expected
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr1.stderr b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr1.stderr
new file mode 100644
index 000000000000..bb2a26379598
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with more arguments than it expected
+  --> $DIR/cast_fn_ptr1.rs:LL:CC
+   |
+LL |     g(42)
+   |     ^^^^^ calling a function with more arguments than it expected
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr2.rs b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr2.rs
new file mode 100644
index 000000000000..20384f0965b8
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr2.rs
@@ -0,0 +1,7 @@
+fn main() {
+    fn f(_: (i32, i32)) {}
+
+    let g = unsafe { std::mem::transmute::<fn((i32, i32)), fn(i32)>(f) };
+
+    g(42) //~ ERROR: calling a function with argument of type (i32, i32) passing data of type i32
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr2.stderr b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr2.stderr
new file mode 100644
index 000000000000..086712e0d13b
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with argument of type (i32, i32) passing data of type i32
+  --> $DIR/cast_fn_ptr2.rs:LL:CC
+   |
+LL |     g(42)
+   |     ^^^^^ calling a function with argument of type (i32, i32) passing data of type i32
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr3.rs b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr3.rs
new file mode 100644
index 000000000000..920fb51abb64
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr3.rs
@@ -0,0 +1,7 @@
+fn main() {
+    fn f(_: (i32, i32)) {}
+
+    let g = unsafe { std::mem::transmute::<fn((i32, i32)), fn()>(f) };
+
+    g() //~ ERROR: calling a function with fewer arguments than it requires
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr3.stderr b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr3.stderr
new file mode 100644
index 000000000000..55fd7d607208
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with fewer arguments than it requires
+  --> $DIR/cast_fn_ptr3.rs:LL:CC
+   |
+LL |     g()
+   |     ^^^ calling a function with fewer arguments than it requires
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr4.rs b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr4.rs
new file mode 100644
index 000000000000..f0ea5ccfe0f5
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr4.rs
@@ -0,0 +1,7 @@
+fn main() {
+    fn f(_: *const [i32]) {}
+
+    let g = unsafe { std::mem::transmute::<fn(*const [i32]), fn(*const i32)>(f) };
+
+    g(&42 as *const i32) //~ ERROR: calling a function with argument of type *const [i32] passing data of type *const i32
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr4.stderr b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr4.stderr
new file mode 100644
index 000000000000..610425658fe1
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr4.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with argument of type *const [i32] passing data of type *const i32
+  --> $DIR/cast_fn_ptr4.rs:LL:CC
+   |
+LL |     g(&42 as *const i32)
+   |     ^^^^^^^^^^^^^^^^^^^^ calling a function with argument of type *const [i32] passing data of type *const i32
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr4.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr5.rs b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr5.rs
new file mode 100644
index 000000000000..0fdab49b94b6
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr5.rs
@@ -0,0 +1,9 @@
+fn main() {
+    fn f() -> u32 {
+        42
+    }
+
+    let g = unsafe { std::mem::transmute::<fn() -> u32, fn()>(f) };
+
+    g() //~ ERROR: calling a function with return type u32 passing return place of type ()
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr5.stderr b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr5.stderr
new file mode 100644
index 000000000000..c4e08b58430a
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_fn_ptr5.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calling a function with return type u32 passing return place of type ()
+  --> $DIR/cast_fn_ptr5.rs:LL:CC
+   |
+LL |     g()
+   |     ^^^ calling a function with return type u32 passing return place of type ()
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr5.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_int_to_fn_ptr.rs b/src/tools/miri/tests/fail/function_pointers/cast_int_to_fn_ptr.rs
new file mode 100644
index 000000000000..dbf8a560fb7a
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_int_to_fn_ptr.rs
@@ -0,0 +1,8 @@
+// Validation makes this fail in the wrong place
+//@compile-flags: -Zmiri-disable-validation
+
+fn main() {
+    let g = unsafe { std::mem::transmute::<usize, fn(i32)>(42) };
+
+    g(42) //~ ERROR: is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/cast_int_to_fn_ptr.stderr b/src/tools/miri/tests/fail/function_pointers/cast_int_to_fn_ptr.stderr
new file mode 100644
index 000000000000..81fc9716a415
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/cast_int_to_fn_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer use: 0x2a[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/cast_int_to_fn_ptr.rs:LL:CC
+   |
+LL |     g(42)
+   |     ^^^^^ out-of-bounds pointer use: 0x2a[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_int_to_fn_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/deref_fn_ptr.rs b/src/tools/miri/tests/fail/function_pointers/deref_fn_ptr.rs
new file mode 100644
index 000000000000..f071b63902fe
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/deref_fn_ptr.rs
@@ -0,0 +1,8 @@
+fn f() {}
+
+fn main() {
+    let x: u8 = unsafe {
+        *std::mem::transmute::<fn(), *const u8>(f) //~ ERROR: out-of-bounds
+    };
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/deref_fn_ptr.stderr b/src/tools/miri/tests/fail/function_pointers/deref_fn_ptr.stderr
new file mode 100644
index 000000000000..7ce0b08695eb
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/deref_fn_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 0, so pointer to 1 byte starting at offset 0 is out-of-bounds
+  --> $DIR/deref_fn_ptr.rs:LL:CC
+   |
+LL |         *std::mem::transmute::<fn(), *const u8>(f)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 0, so pointer to 1 byte starting at offset 0 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/deref_fn_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/execute_memory.rs b/src/tools/miri/tests/fail/function_pointers/execute_memory.rs
new file mode 100644
index 000000000000..967933e769b8
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/execute_memory.rs
@@ -0,0 +1,12 @@
+// Validation makes this fail in the wrong place
+//@compile-flags: -Zmiri-disable-validation
+
+#![feature(box_syntax)]
+
+fn main() {
+    let x = box 42;
+    unsafe {
+        let f = std::mem::transmute::<Box<i32>, fn()>(x);
+        f() //~ ERROR: function pointer but it does not point to a function
+    }
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/execute_memory.stderr b/src/tools/miri/tests/fail/function_pointers/execute_memory.stderr
new file mode 100644
index 000000000000..10c53ca2beae
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/execute_memory.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using ALLOC as function pointer but it does not point to a function
+  --> $DIR/execute_memory.rs:LL:CC
+   |
+LL |         f()
+   |         ^^^ using ALLOC as function pointer but it does not point to a function
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/execute_memory.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/function_pointers/fn_ptr_offset.rs b/src/tools/miri/tests/fail/function_pointers/fn_ptr_offset.rs
new file mode 100644
index 000000000000..eba0953ac863
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/fn_ptr_offset.rs
@@ -0,0 +1,14 @@
+// Validation makes this fail in the wrong place
+//@compile-flags: -Zmiri-disable-validation
+
+use std::mem;
+
+fn f() {}
+
+fn main() {
+    let x: fn() = f;
+    let y: *mut u8 = unsafe { mem::transmute(x) };
+    let y = y.wrapping_offset(1);
+    let x: fn() = unsafe { mem::transmute(y) };
+    x(); //~ ERROR: function pointer but it does not point to a function
+}
diff --git a/src/tools/miri/tests/fail/function_pointers/fn_ptr_offset.stderr b/src/tools/miri/tests/fail/function_pointers/fn_ptr_offset.stderr
new file mode 100644
index 000000000000..f8c519c1b54b
--- /dev/null
+++ b/src/tools/miri/tests/fail/function_pointers/fn_ptr_offset.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using ALLOC+0x1 as function pointer but it does not point to a function
+  --> $DIR/fn_ptr_offset.rs:LL:CC
+   |
+LL |     x();
+   |     ^^^ using ALLOC+0x1 as function pointer but it does not point to a function
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/fn_ptr_offset.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/generator-pinned-moved.rs b/src/tools/miri/tests/fail/generator-pinned-moved.rs
new file mode 100644
index 000000000000..240ae18cc45a
--- /dev/null
+++ b/src/tools/miri/tests/fail/generator-pinned-moved.rs
@@ -0,0 +1,45 @@
+//@compile-flags: -Zmiri-disable-validation
+#![feature(generators, generator_trait)]
+
+use std::{
+    ops::{Generator, GeneratorState},
+    pin::Pin,
+};
+
+fn firstn() -> impl Generator<Yield = u64, Return = ()> {
+    static move || {
+        let mut num = 0;
+        let num = &mut num;
+
+        yield *num;
+        *num += 1; //~ ERROR: dereferenced after this allocation got freed
+    }
+}
+
+struct GeneratorIteratorAdapter<G>(G);
+
+impl<G> Iterator for GeneratorIteratorAdapter<G>
+where
+    G: Generator<Return = ()>,
+{
+    type Item = G::Yield;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let me = unsafe { Pin::new_unchecked(&mut self.0) };
+        match me.resume(()) {
+            GeneratorState::Yielded(x) => Some(x),
+            GeneratorState::Complete(_) => None,
+        }
+    }
+}
+
+fn main() {
+    let mut generator_iterator_2 = {
+        let mut generator_iterator = Box::new(GeneratorIteratorAdapter(firstn()));
+        generator_iterator.next(); // pin it
+
+        Box::new(*generator_iterator) // move it
+    }; // *deallocate* generator_iterator
+
+    generator_iterator_2.next(); // and use moved value
+}
diff --git a/src/tools/miri/tests/fail/generator-pinned-moved.stderr b/src/tools/miri/tests/fail/generator-pinned-moved.stderr
new file mode 100644
index 000000000000..4f73671a7894
--- /dev/null
+++ b/src/tools/miri/tests/fail/generator-pinned-moved.stderr
@@ -0,0 +1,26 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/generator-pinned-moved.rs:LL:CC
+   |
+LL |         *num += 1;
+   |         ^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/generator-pinned-moved.rs:LL:CC
+note: inside `<GeneratorIteratorAdapter<[static generator@$DIR/generator-pinned-moved.rs:LL:CC]> as std::iter::Iterator>::next` at $DIR/generator-pinned-moved.rs:LL:CC
+  --> $DIR/generator-pinned-moved.rs:LL:CC
+   |
+LL |         match me.resume(()) {
+   |               ^^^^^^^^^^^^^
+   = note: inside `<std::boxed::Box<GeneratorIteratorAdapter<[static generator@$DIR/generator-pinned-moved.rs:LL:CC]>> as std::iter::Iterator>::next` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+note: inside `main` at $DIR/generator-pinned-moved.rs:LL:CC
+  --> $DIR/generator-pinned-moved.rs:LL:CC
+   |
+LL |     generator_iterator_2.next(); // and use moved value
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/assume.rs b/src/tools/miri/tests/fail/intrinsics/assume.rs
new file mode 100644
index 000000000000..c34827427ef0
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/assume.rs
@@ -0,0 +1,10 @@
+#![feature(core_intrinsics)]
+
+fn main() {
+    let x = 5;
+    unsafe {
+        std::intrinsics::assume(x < 10);
+        std::intrinsics::assume(x > 1);
+        std::intrinsics::assume(x > 42); //~ ERROR: `assume` called with `false`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/assume.stderr b/src/tools/miri/tests/fail/intrinsics/assume.stderr
new file mode 100644
index 000000000000..c1909570d99f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/assume.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `assume` called with `false`
+  --> $DIR/assume.rs:LL:CC
+   |
+LL |         std::intrinsics::assume(x > 42);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `assume` called with `false`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/assume.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_null.rs b/src/tools/miri/tests/fail/intrinsics/copy_null.rs
new file mode 100644
index 000000000000..237e517f2875
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_null.rs
@@ -0,0 +1,15 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+}
+
+fn main() {
+    let mut data = [0u16; 4];
+    let ptr = &mut data[0] as *mut u16;
+    // Even copying 0 elements from NULL should error.
+    unsafe {
+        copy_nonoverlapping(std::ptr::null(), ptr, 0); //~ ERROR: memory access failed: null pointer is a dangling pointer
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_null.stderr b/src/tools/miri/tests/fail/intrinsics/copy_null.stderr
new file mode 100644
index 000000000000..6e3215d9f1c9
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_null.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: memory access failed: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/copy_null.rs:LL:CC
+   |
+LL |         copy_nonoverlapping(std::ptr::null(), ptr, 0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/copy_null.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_overflow.rs b/src/tools/miri/tests/fail/intrinsics/copy_overflow.rs
new file mode 100644
index 000000000000..e64a1f909021
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_overflow.rs
@@ -0,0 +1,10 @@
+use std::mem;
+
+fn main() {
+    let x = 0;
+    let mut y = 0;
+    unsafe {
+        (&mut y as *mut i32).copy_from(&x, 1usize << (mem::size_of::<usize>() * 8 - 1));
+        //~^ERROR: overflow computing total size
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_overflow.stderr b/src/tools/miri/tests/fail/intrinsics/copy_overflow.stderr
new file mode 100644
index 000000000000..23a4adbd0ed6
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_overflow.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow computing total size of `copy`
+  --> $DIR/copy_overflow.rs:LL:CC
+   |
+LL |         (&mut y as *mut i32).copy_from(&x, 1usize << (mem::size_of::<usize>() * 8 - 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow computing total size of `copy`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/copy_overflow.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs
new file mode 100644
index 000000000000..3df881bd43ca
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs
@@ -0,0 +1,15 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+}
+
+fn main() {
+    let mut data = [0u8; 16];
+    unsafe {
+        let a = data.as_mut_ptr();
+        let b = a.wrapping_offset(1) as *mut _;
+        copy_nonoverlapping(a, b, 2); //~ ERROR: copy_nonoverlapping called on overlapping ranges
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr
new file mode 100644
index 000000000000..cdb3da74ca95
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: copy_nonoverlapping called on overlapping ranges
+  --> $DIR/copy_overlapping.rs:LL:CC
+   |
+LL |         copy_nonoverlapping(a, b, 2);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ copy_nonoverlapping called on overlapping ranges
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/copy_overlapping.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_unaligned.rs b/src/tools/miri/tests/fail/intrinsics/copy_unaligned.rs
new file mode 100644
index 000000000000..281217f06f51
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_unaligned.rs
@@ -0,0 +1,15 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+}
+
+fn main() {
+    let mut data = [0u16; 8];
+    let ptr = (&mut data[0] as *mut u16 as *mut u8).wrapping_add(1) as *mut u16;
+    // Even copying 0 elements to something unaligned should error
+    unsafe {
+        copy_nonoverlapping(&data[5], ptr, 0); //~ ERROR: accessing memory with alignment 1, but alignment 2 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_unaligned.stderr b/src/tools/miri/tests/fail/intrinsics/copy_unaligned.stderr
new file mode 100644
index 000000000000..a275979e6be1
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/copy_unaligned.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/copy_unaligned.rs:LL:CC
+   |
+LL |         copy_nonoverlapping(&data[5], ptr, 0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/copy_unaligned.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ctlz_nonzero.rs b/src/tools/miri/tests/fail/intrinsics/ctlz_nonzero.rs
new file mode 100644
index 000000000000..c26cd4cadb53
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ctlz_nonzero.rs
@@ -0,0 +1,15 @@
+#![feature(intrinsics)]
+
+mod rusti {
+    extern "rust-intrinsic" {
+        pub fn ctlz_nonzero<T>(x: T) -> T;
+    }
+}
+
+pub fn main() {
+    unsafe {
+        use crate::rusti::*;
+
+        ctlz_nonzero(0u8); //~ ERROR: `ctlz_nonzero` called on 0
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ctlz_nonzero.stderr b/src/tools/miri/tests/fail/intrinsics/ctlz_nonzero.stderr
new file mode 100644
index 000000000000..5ae14472a8a6
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ctlz_nonzero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `ctlz_nonzero` called on 0
+  --> $DIR/ctlz_nonzero.rs:LL:CC
+   |
+LL |         ctlz_nonzero(0u8);
+   |         ^^^^^^^^^^^^^^^^^ `ctlz_nonzero` called on 0
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ctlz_nonzero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/cttz_nonzero.rs b/src/tools/miri/tests/fail/intrinsics/cttz_nonzero.rs
new file mode 100644
index 000000000000..25a0501fdd80
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/cttz_nonzero.rs
@@ -0,0 +1,15 @@
+#![feature(intrinsics)]
+
+mod rusti {
+    extern "rust-intrinsic" {
+        pub fn cttz_nonzero<T>(x: T) -> T;
+    }
+}
+
+pub fn main() {
+    unsafe {
+        use crate::rusti::*;
+
+        cttz_nonzero(0u8); //~ ERROR: `cttz_nonzero` called on 0
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/cttz_nonzero.stderr b/src/tools/miri/tests/fail/intrinsics/cttz_nonzero.stderr
new file mode 100644
index 000000000000..ae013fb3d979
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/cttz_nonzero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `cttz_nonzero` called on 0
+  --> $DIR/cttz_nonzero.rs:LL:CC
+   |
+LL |         cttz_nonzero(0u8);
+   |         ^^^^^^^^^^^^^^^^^ `cttz_nonzero` called on 0
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cttz_nonzero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/div-by-zero.rs b/src/tools/miri/tests/fail/intrinsics/div-by-zero.rs
new file mode 100644
index 000000000000..78c05c543a8f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/div-by-zero.rs
@@ -0,0 +1,9 @@
+#![feature(core_intrinsics)]
+
+use std::intrinsics::*;
+
+fn main() {
+    unsafe {
+        let _n = unchecked_div(1i64, 0); //~ERROR: dividing by zero
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/div-by-zero.stderr b/src/tools/miri/tests/fail/intrinsics/div-by-zero.stderr
new file mode 100644
index 000000000000..8c2910de3eef
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/div-by-zero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dividing by zero
+  --> $DIR/div-by-zero.rs:LL:CC
+   |
+LL |         let _n = unchecked_div(1i64, 0);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^ dividing by zero
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/div-by-zero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div1.rs b/src/tools/miri/tests/fail/intrinsics/exact_div1.rs
new file mode 100644
index 000000000000..3dda9d1090de
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div1.rs
@@ -0,0 +1,5 @@
+#![feature(core_intrinsics)]
+fn main() {
+    // divison by 0
+    unsafe { std::intrinsics::exact_div(2, 0) }; //~ ERROR: divisor of zero
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div1.stderr b/src/tools/miri/tests/fail/intrinsics/exact_div1.stderr
new file mode 100644
index 000000000000..2c7bbc00e1b1
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calculating the remainder with a divisor of zero
+  --> $DIR/exact_div1.rs:LL:CC
+   |
+LL |     unsafe { std::intrinsics::exact_div(2, 0) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ calculating the remainder with a divisor of zero
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exact_div1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div2.rs b/src/tools/miri/tests/fail/intrinsics/exact_div2.rs
new file mode 100644
index 000000000000..00064fa0b9c1
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div2.rs
@@ -0,0 +1,5 @@
+#![feature(core_intrinsics)]
+fn main() {
+    // divison with a remainder
+    unsafe { std::intrinsics::exact_div(2u16, 3) }; //~ ERROR: 2_u16 cannot be divided by 3_u16 without remainder
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div2.stderr b/src/tools/miri/tests/fail/intrinsics/exact_div2.stderr
new file mode 100644
index 000000000000..6a264b8b4476
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: exact_div: 2_u16 cannot be divided by 3_u16 without remainder
+  --> $DIR/exact_div2.rs:LL:CC
+   |
+LL |     unsafe { std::intrinsics::exact_div(2u16, 3) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ exact_div: 2_u16 cannot be divided by 3_u16 without remainder
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exact_div2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div3.rs b/src/tools/miri/tests/fail/intrinsics/exact_div3.rs
new file mode 100644
index 000000000000..a61abcd137e1
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div3.rs
@@ -0,0 +1,5 @@
+#![feature(core_intrinsics)]
+fn main() {
+    // signed divison with a remainder
+    unsafe { std::intrinsics::exact_div(-19i8, 2) }; //~ ERROR: -19_i8 cannot be divided by 2_i8 without remainder
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div3.stderr b/src/tools/miri/tests/fail/intrinsics/exact_div3.stderr
new file mode 100644
index 000000000000..1a73822c300f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: exact_div: -19_i8 cannot be divided by 2_i8 without remainder
+  --> $DIR/exact_div3.rs:LL:CC
+   |
+LL |     unsafe { std::intrinsics::exact_div(-19i8, 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ exact_div: -19_i8 cannot be divided by 2_i8 without remainder
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exact_div3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div4.rs b/src/tools/miri/tests/fail/intrinsics/exact_div4.rs
new file mode 100644
index 000000000000..b5b60190b4ec
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div4.rs
@@ -0,0 +1,5 @@
+#![feature(core_intrinsics)]
+fn main() {
+    // divison of MIN by -1
+    unsafe { std::intrinsics::exact_div(i64::MIN, -1) }; //~ ERROR: overflow in signed remainder (dividing MIN by -1)
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/exact_div4.stderr b/src/tools/miri/tests/fail/intrinsics/exact_div4.stderr
new file mode 100644
index 000000000000..27201d9c7cf6
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/exact_div4.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow in signed remainder (dividing MIN by -1)
+  --> $DIR/exact_div4.rs:LL:CC
+   |
+LL |     unsafe { std::intrinsics::exact_div(i64::MIN, -1) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow in signed remainder (dividing MIN by -1)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exact_div4.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_inf1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_inf1.rs
new file mode 100644
index 000000000000..a57845426d58
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_inf1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, i32>(f32::INFINITY); //~ ERROR: cannot be represented in target type `i32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_inf1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_inf1.stderr
new file mode 100644
index 000000000000..c82d6b30224f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_inf1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on +Inf which cannot be represented in target type `i32`
+  --> $DIR/float_to_int_32_inf1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, i32>(f32::INFINITY);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on +Inf which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_inf1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_infneg1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_infneg1.rs
new file mode 100644
index 000000000000..d383fc5b50ac
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_infneg1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, i32>(f32::NEG_INFINITY); //~ ERROR: cannot be represented in target type `i32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_infneg1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_infneg1.stderr
new file mode 100644
index 000000000000..4ca41b676e9c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_infneg1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -Inf which cannot be represented in target type `i32`
+  --> $DIR/float_to_int_32_infneg1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, i32>(f32::NEG_INFINITY);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -Inf which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_infneg1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nan.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nan.rs
new file mode 100644
index 000000000000..a39a5066b6f8
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nan.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, u32>(f32::NAN); //~ ERROR: cannot be represented in target type `u32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nan.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nan.stderr
new file mode 100644
index 000000000000..88b8948b0c29
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nan.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on NaN which cannot be represented in target type `u32`
+  --> $DIR/float_to_int_32_nan.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, u32>(f32::NAN);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on NaN which cannot be represented in target type `u32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_nan.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nanneg.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nanneg.rs
new file mode 100644
index 000000000000..71436eb3ba84
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nanneg.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, u32>(-f32::NAN); //~ ERROR: cannot be represented in target type `u32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nanneg.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nanneg.stderr
new file mode 100644
index 000000000000..ca798dd391aa
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_nanneg.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on NaN which cannot be represented in target type `u32`
+  --> $DIR/float_to_int_32_nanneg.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, u32>(-f32::NAN);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on NaN which cannot be represented in target type `u32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_nanneg.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_neg.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_neg.rs
new file mode 100644
index 000000000000..98ba964e47c2
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_neg.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, u32>(-1.000000001f32); //~ ERROR: cannot be represented in target type `u32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_neg.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_neg.stderr
new file mode 100644
index 000000000000..4ff6eb809854
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_neg.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -1 which cannot be represented in target type `u32`
+  --> $DIR/float_to_int_32_neg.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, u32>(-1.000000001f32);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -1 which cannot be represented in target type `u32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_neg.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big1.rs
new file mode 100644
index 000000000000..424b8fd965e9
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, i32>(2147483648.0f32); //~ ERROR: cannot be represented in target type `i32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big1.stderr
new file mode 100644
index 000000000000..fd17709d164b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 2.14748365E+9 which cannot be represented in target type `i32`
+  --> $DIR/float_to_int_32_too_big1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, i32>(2147483648.0f32);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 2.14748365E+9 which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_too_big1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big2.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big2.rs
new file mode 100644
index 000000000000..5c50926c4df3
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big2.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, u32>((u32::MAX - 127) as f32); //~ ERROR: cannot be represented in target type `u32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big2.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big2.stderr
new file mode 100644
index 000000000000..fdc1f65dc148
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_big2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 4.2949673E+9 which cannot be represented in target type `u32`
+  --> $DIR/float_to_int_32_too_big2.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, u32>((u32::MAX - 127) as f32);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 4.2949673E+9 which cannot be represented in target type `u32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_too_big2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_small1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_small1.rs
new file mode 100644
index 000000000000..e0abd19d03fc
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_small1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f32, i32>(-2147483904.0f32); //~ ERROR: cannot be represented in target type `i32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_small1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_small1.stderr
new file mode 100644
index 000000000000..9e743a321444
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_32_too_small1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -2.1474839E+9 which cannot be represented in target type `i32`
+  --> $DIR/float_to_int_32_too_small1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f32, i32>(-2147483904.0f32);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -2.1474839E+9 which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_32_too_small1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_inf1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_inf1.rs
new file mode 100644
index 000000000000..f5f842e58ece
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_inf1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u128>(f64::INFINITY); //~ ERROR: cannot be represented in target type `u128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_inf1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_inf1.stderr
new file mode 100644
index 000000000000..ee01143dc8df
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_inf1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on +Inf which cannot be represented in target type `u128`
+  --> $DIR/float_to_int_64_inf1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u128>(f64::INFINITY);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on +Inf which cannot be represented in target type `u128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_inf1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg1.rs
new file mode 100644
index 000000000000..244c25b31cbf
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u128>(f64::NEG_INFINITY); //~ ERROR: cannot be represented in target type `u128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg1.stderr
new file mode 100644
index 000000000000..f37b8ae55064
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -Inf which cannot be represented in target type `u128`
+  --> $DIR/float_to_int_64_infneg1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u128>(f64::NEG_INFINITY);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -Inf which cannot be represented in target type `u128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_infneg1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg2.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg2.rs
new file mode 100644
index 000000000000..f7a663d12a56
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg2.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i128>(f64::NEG_INFINITY); //~ ERROR: cannot be represented in target type `i128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg2.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg2.stderr
new file mode 100644
index 000000000000..05dcd5ebcf69
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_infneg2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -Inf which cannot be represented in target type `i128`
+  --> $DIR/float_to_int_64_infneg2.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i128>(f64::NEG_INFINITY);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -Inf which cannot be represented in target type `i128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_infneg2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_nan.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_nan.rs
new file mode 100644
index 000000000000..171cbcc59344
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_nan.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u32>(f64::NAN); //~ ERROR: cannot be represented in target type `u32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_nan.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_nan.stderr
new file mode 100644
index 000000000000..0a914abb2ce7
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_nan.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on NaN which cannot be represented in target type `u32`
+  --> $DIR/float_to_int_64_nan.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u32>(f64::NAN);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on NaN which cannot be represented in target type `u32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_nan.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_neg.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_neg.rs
new file mode 100644
index 000000000000..40b67e173b97
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_neg.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u128>(-1.0000000000001f64); //~ ERROR: cannot be represented in target type `u128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_neg.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_neg.stderr
new file mode 100644
index 000000000000..7e24f45f653d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_neg.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -1 which cannot be represented in target type `u128`
+  --> $DIR/float_to_int_64_neg.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u128>(-1.0000000000001f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -1 which cannot be represented in target type `u128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_neg.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big1.rs
new file mode 100644
index 000000000000..e785123c4ca9
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i32>(2147483648.0f64); //~ ERROR: cannot be represented in target type `i32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big1.stderr
new file mode 100644
index 000000000000..42da33321f37
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 2147483648 which cannot be represented in target type `i32`
+  --> $DIR/float_to_int_64_too_big1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i32>(2147483648.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 2147483648 which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big2.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big2.rs
new file mode 100644
index 000000000000..4bf31d8ac027
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big2.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i64>(9223372036854775808.0f64); //~ ERROR: cannot be represented in target type `i64`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big2.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big2.stderr
new file mode 100644
index 000000000000..af4c4ceb3f73
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 9.2233720368547758E+18 which cannot be represented in target type `i64`
+  --> $DIR/float_to_int_64_too_big2.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i64>(9223372036854775808.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 9.2233720368547758E+18 which cannot be represented in target type `i64`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big3.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big3.rs
new file mode 100644
index 000000000000..9775a56724bc
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big3.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u64>(18446744073709551616.0f64); //~ ERROR: cannot be represented in target type `u64`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big3.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big3.stderr
new file mode 100644
index 000000000000..6e384a6fbc7c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 1.8446744073709552E+19 which cannot be represented in target type `u64`
+  --> $DIR/float_to_int_64_too_big3.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u64>(18446744073709551616.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 1.8446744073709552E+19 which cannot be represented in target type `u64`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big4.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big4.rs
new file mode 100644
index 000000000000..53ff06e1e467
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big4.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u128>(u128::MAX as f64); //~ ERROR: cannot be represented in target type `u128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big4.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big4.stderr
new file mode 100644
index 000000000000..77f05ff91e3b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big4.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 3.4028236692093846E+38 which cannot be represented in target type `u128`
+  --> $DIR/float_to_int_64_too_big4.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u128>(u128::MAX as f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 3.4028236692093846E+38 which cannot be represented in target type `u128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big4.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big5.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big5.rs
new file mode 100644
index 000000000000..44356ff1771b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big5.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i128>(240282366920938463463374607431768211455.0f64); //~ ERROR: cannot be represented in target type `i128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big5.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big5.stderr
new file mode 100644
index 000000000000..cb5eba490b44
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big5.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 2.4028236692093845E+38 which cannot be represented in target type `i128`
+  --> $DIR/float_to_int_64_too_big5.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i128>(240282366920938463463374607431768211455.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 2.4028236692093845E+38 which cannot be represented in target type `i128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big5.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big6.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big6.rs
new file mode 100644
index 000000000000..66f5be96bfd0
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big6.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, u128>(f64::MAX); //~ ERROR: cannot be represented in target type `u128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big6.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big6.stderr
new file mode 100644
index 000000000000..d899d2f808a5
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big6.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 1.7976931348623157E+308 which cannot be represented in target type `u128`
+  --> $DIR/float_to_int_64_too_big6.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, u128>(f64::MAX);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 1.7976931348623157E+308 which cannot be represented in target type `u128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big6.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big7.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big7.rs
new file mode 100644
index 000000000000..18b380e8575e
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big7.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i128>(f64::MIN); //~ ERROR: cannot be represented in target type `i128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big7.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big7.stderr
new file mode 100644
index 000000000000..443b2759c260
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_big7.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -1.7976931348623157E+308 which cannot be represented in target type `i128`
+  --> $DIR/float_to_int_64_too_big7.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i128>(f64::MIN);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -1.7976931348623157E+308 which cannot be represented in target type `i128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_big7.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small1.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small1.rs
new file mode 100644
index 000000000000..2a23b1dc8a4b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small1.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i32>(-2147483649.0f64); //~ ERROR: cannot be represented in target type `i32`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small1.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small1.stderr
new file mode 100644
index 000000000000..f8d88c44aa80
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -2147483649 which cannot be represented in target type `i32`
+  --> $DIR/float_to_int_64_too_small1.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i32>(-2147483649.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -2147483649 which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_small1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small2.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small2.rs
new file mode 100644
index 000000000000..7fc3effda5df
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small2.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i64>(-9223372036854777856.0f64); //~ ERROR: cannot be represented in target type `i64`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small2.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small2.stderr
new file mode 100644
index 000000000000..d94e57b1e67c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -9.2233720368547778E+18 which cannot be represented in target type `i64`
+  --> $DIR/float_to_int_64_too_small2.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i64>(-9223372036854777856.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -9.2233720368547778E+18 which cannot be represented in target type `i64`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_small2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small3.rs b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small3.rs
new file mode 100644
index 000000000000..2a8f9c366425
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small3.rs
@@ -0,0 +1,12 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int;
+}
+
+fn main() {
+    unsafe {
+        float_to_int_unchecked::<f64, i128>(-240282366920938463463374607431768211455.0f64); //~ ERROR: cannot be represented in target type `i128`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small3.stderr b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small3.stderr
new file mode 100644
index 000000000000..59b74f5f51f3
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/float_to_int_64_too_small3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on -2.4028236692093845E+38 which cannot be represented in target type `i128`
+  --> $DIR/float_to_int_64_too_small3.rs:LL:CC
+   |
+LL |         float_to_int_unchecked::<f64, i128>(-240282366920938463463374607431768211455.0f64);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on -2.4028236692093845E+38 which cannot be represented in target type `i128`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/float_to_int_64_too_small3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_1.rs b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_1.rs
new file mode 100644
index 000000000000..b6a110ee84d2
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_1.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let v = [0i8; 4];
+    let x = &v as *const i8;
+    // The error is inside another function, so we cannot match it by line
+    let x = unsafe { x.offset(5) }; //~ERROR: pointer to 5 bytes starting at offset 0 is out-of-bounds
+    panic!("this should never print: {:?}", x);
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_1.stderr b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_1.stderr
new file mode 100644
index 000000000000..4422310870a6
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: ALLOC has size 4, so pointer to 5 bytes starting at offset 0 is out-of-bounds
+  --> $DIR/out_of_bounds_ptr_1.rs:LL:CC
+   |
+LL |     let x = unsafe { x.offset(5) };
+   |                      ^^^^^^^^^^^ out-of-bounds pointer arithmetic: ALLOC has size 4, so pointer to 5 bytes starting at offset 0 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/out_of_bounds_ptr_1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_2.rs b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_2.rs
new file mode 100644
index 000000000000..0d4eea9a5bde
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_2.rs
@@ -0,0 +1,6 @@
+fn main() {
+    let v = [0i8; 4];
+    let x = &v as *const i8;
+    let x = unsafe { x.offset(isize::MIN) }; //~ERROR: overflowing in-bounds pointer arithmetic
+    panic!("this should never print: {:?}", x);
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_2.stderr b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_2.stderr
new file mode 100644
index 000000000000..6a11ebae108f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing in-bounds pointer arithmetic
+  --> $DIR/out_of_bounds_ptr_2.rs:LL:CC
+   |
+LL |     let x = unsafe { x.offset(isize::MIN) };
+   |                      ^^^^^^^^^^^^^^^^^^^^ overflowing in-bounds pointer arithmetic
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/out_of_bounds_ptr_2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_3.rs b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_3.rs
new file mode 100644
index 000000000000..701bc33a645e
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_3.rs
@@ -0,0 +1,6 @@
+fn main() {
+    let v = [0i8; 4];
+    let x = &v as *const i8;
+    let x = unsafe { x.offset(-1) }; //~ERROR: pointer to 1 byte starting at offset -1 is out-of-bounds
+    panic!("this should never print: {:?}", x);
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_3.stderr b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_3.stderr
new file mode 100644
index 000000000000..1364e0f9009d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/out_of_bounds_ptr_3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: ALLOC has size 4, so pointer to 1 byte starting at offset -1 is out-of-bounds
+  --> $DIR/out_of_bounds_ptr_3.rs:LL:CC
+   |
+LL |     let x = unsafe { x.offset(-1) };
+   |                      ^^^^^^^^^^^^ out-of-bounds pointer arithmetic: ALLOC has size 4, so pointer to 1 byte starting at offset -1 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/out_of_bounds_ptr_3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/overflowing-unchecked-rsh.rs b/src/tools/miri/tests/fail/intrinsics/overflowing-unchecked-rsh.rs
new file mode 100644
index 000000000000..fe2e85be6986
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/overflowing-unchecked-rsh.rs
@@ -0,0 +1,8 @@
+#![feature(unchecked_math)]
+
+fn main() {
+    unsafe {
+        let _n = 1i64.unchecked_shr(64);
+        //~^ ERROR: overflowing shift by 64 in `unchecked_shr`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/overflowing-unchecked-rsh.stderr b/src/tools/miri/tests/fail/intrinsics/overflowing-unchecked-rsh.stderr
new file mode 100644
index 000000000000..9c5d0d13108c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/overflowing-unchecked-rsh.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing shift by 64 in `unchecked_shr`
+  --> $DIR/overflowing-unchecked-rsh.rs:LL:CC
+   |
+LL |         let _n = 1i64.unchecked_shr(64);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^ overflowing shift by 64 in `unchecked_shr`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/overflowing-unchecked-rsh.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_0_plus_0.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_0_plus_0.rs
new file mode 100644
index 000000000000..e2329c131398
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_0_plus_0.rs
@@ -0,0 +1,9 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+#[rustfmt::skip] // fails with "left behind trailing whitespace"
+fn main() {
+    let x = 0 as *mut i32;
+    let _x = x.wrapping_offset(8); // ok, this has no inbounds tag
+    let _x = unsafe { x.offset(0) }; // UB despite offset 0, NULL is never inbounds
+    //~^ERROR: null pointer is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_0_plus_0.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_0_plus_0.stderr
new file mode 100644
index 000000000000..9c1c387d5499
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_0_plus_0.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/ptr_offset_0_plus_0.rs:LL:CC
+   |
+LL |     let _x = unsafe { x.offset(0) }; // UB despite offset 0, NULL is never inbounds
+   |                       ^^^^^^^^^^^ out-of-bounds pointer arithmetic: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_0_plus_0.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.rs
new file mode 100644
index 000000000000..0e5acf08b203
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let start_ptr = &4 as *const _ as *const u8;
+    let length = 10;
+    let end_ptr = start_ptr.wrapping_add(length);
+    // Even if the offset is 0, a dangling OOB pointer is not allowed.
+    unsafe { end_ptr.offset_from(end_ptr) }; //~ERROR: pointer at offset 10 is out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
new file mode 100644
index 000000000000..a31b929d7a7a
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds offset_from: ALLOC has size 4, so pointer at offset 10 is out-of-bounds
+  --> $DIR/ptr_offset_from_oob.rs:LL:CC
+   |
+LL |     unsafe { end_ptr.offset_from(end_ptr) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds offset_from: ALLOC has size 4, so pointer at offset 10 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_from_oob.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_unsigned_neg.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_unsigned_neg.rs
new file mode 100644
index 000000000000..06d13d9bdbaf
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_unsigned_neg.rs
@@ -0,0 +1,8 @@
+#![feature(ptr_sub_ptr)]
+
+fn main() {
+    let arr = [0u8; 8];
+    let ptr1 = arr.as_ptr();
+    let ptr2 = ptr1.wrapping_add(4);
+    let _val = unsafe { ptr1.sub_ptr(ptr2) }; //~ERROR: first pointer has smaller offset than second: 0 < 4
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_unsigned_neg.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_unsigned_neg.stderr
new file mode 100644
index 000000000000..803aaaa55c21
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_unsigned_neg.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `ptr_offset_from_unsigned` called when first pointer has smaller offset than second: 0 < 4
+  --> $DIR/ptr_offset_from_unsigned_neg.rs:LL:CC
+   |
+LL |     let _val = unsafe { ptr1.sub_ptr(ptr2) };
+   |                         ^^^^^^^^^^^^^^^^^^ `ptr_offset_from_unsigned` called when first pointer has smaller offset than second: 0 < 4
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_from_unsigned_neg.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_int.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_int.rs
new file mode 100644
index 000000000000..19bd265c1435
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_int.rs
@@ -0,0 +1,8 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    // Can't offset an integer pointer by non-zero offset.
+    unsafe {
+        let _val = (1 as *mut u8).offset(1); //~ERROR: is a dangling pointer
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_int.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_int.stderr
new file mode 100644
index 000000000000..f76881011d07
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_int.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: 0x1[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/ptr_offset_int_plus_int.rs:LL:CC
+   |
+LL |         let _val = (1 as *mut u8).offset(1);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer arithmetic: 0x1[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_int_plus_int.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_ptr.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_ptr.rs
new file mode 100644
index 000000000000..fd3c9b44615c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_ptr.rs
@@ -0,0 +1,9 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    let ptr = Box::into_raw(Box::new(0u32));
+    // Can't start with an integer pointer and get to something usable
+    unsafe {
+        let _val = (1 as *mut u8).offset(ptr as isize); //~ERROR: is a dangling pointer
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_ptr.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_ptr.stderr
new file mode 100644
index 000000000000..6e0744b7d5c3
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_int_plus_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: 0x1[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/ptr_offset_int_plus_ptr.rs:LL:CC
+   |
+LL |         let _val = (1 as *mut u8).offset(ptr as isize);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer arithmetic: 0x1[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_int_plus_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_overflow.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_overflow.rs
new file mode 100644
index 000000000000..c3db1e23b9bf
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_overflow.rs
@@ -0,0 +1,5 @@
+fn main() {
+    let v = [1i8, 2];
+    let x = &v[1] as *const i8;
+    let _val = unsafe { x.offset(isize::MIN) }; //~ERROR: overflowing in-bounds pointer arithmetic
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_overflow.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_overflow.stderr
new file mode 100644
index 000000000000..6fb94cf5f812
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_overflow.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing in-bounds pointer arithmetic
+  --> $DIR/ptr_offset_overflow.rs:LL:CC
+   |
+LL |     let _val = unsafe { x.offset(isize::MIN) };
+   |                         ^^^^^^^^^^^^^^^^^^^^ overflowing in-bounds pointer arithmetic
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_overflow.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_ptr_plus_0.rs b/src/tools/miri/tests/fail/intrinsics/ptr_offset_ptr_plus_0.rs
new file mode 100644
index 000000000000..575e28854b1a
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_ptr_plus_0.rs
@@ -0,0 +1,7 @@
+#[rustfmt::skip] // fails with "left behind trailing whitespace"
+fn main() {
+    let x = Box::into_raw(Box::new(0u32));
+    let x = x.wrapping_offset(8); // ok, this has no inbounds tag
+    let _x = unsafe { x.offset(0) }; // UB despite offset 0, the pointer is not inbounds of the only object it can point to
+    //~^ERROR: pointer at offset 32 is out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_ptr_plus_0.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_ptr_plus_0.stderr
new file mode 100644
index 000000000000..b18147ce379d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_ptr_plus_0.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: ALLOC has size 4, so pointer at offset 32 is out-of-bounds
+  --> $DIR/ptr_offset_ptr_plus_0.rs:LL:CC
+   |
+LL |     let _x = unsafe { x.offset(0) }; // UB despite offset 0, the pointer is not inbounds of the only object it can point to
+   |                       ^^^^^^^^^^^ out-of-bounds pointer arithmetic: ALLOC has size 4, so pointer at offset 32 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_ptr_plus_0.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.rs b/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.rs
new file mode 100644
index 000000000000..c14f86147dbb
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.rs
@@ -0,0 +1,10 @@
+#![feature(intrinsics)]
+
+extern "rust-intrinsic" {
+    fn raw_eq<T>(a: &T, b: &T) -> bool;
+}
+
+fn main() {
+    let x = &0;
+    unsafe { raw_eq(&x, &x) }; //~ERROR: `raw_eq` on bytes with provenance
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.stderr b/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.stderr
new file mode 100644
index 000000000000..2236ad9839c5
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `raw_eq` on bytes with provenance
+  --> $DIR/raw_eq_on_ptr.rs:LL:CC
+   |
+LL |     unsafe { raw_eq(&x, &x) };
+   |              ^^^^^^^^^^^^^^ `raw_eq` on bytes with provenance
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/raw_eq_on_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/rem-by-zero.rs b/src/tools/miri/tests/fail/intrinsics/rem-by-zero.rs
new file mode 100644
index 000000000000..ac80852e8dcf
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/rem-by-zero.rs
@@ -0,0 +1,9 @@
+#![feature(core_intrinsics)]
+
+use std::intrinsics::*;
+
+fn main() {
+    unsafe {
+        let _n = unchecked_rem(3u32, 0); //~ ERROR: calculating the remainder with a divisor of zero
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/rem-by-zero.stderr b/src/tools/miri/tests/fail/intrinsics/rem-by-zero.stderr
new file mode 100644
index 000000000000..1fc39188e5a9
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/rem-by-zero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calculating the remainder with a divisor of zero
+  --> $DIR/rem-by-zero.rs:LL:CC
+   |
+LL |         let _n = unchecked_rem(3u32, 0);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^ calculating the remainder with a divisor of zero
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/rem-by-zero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-div-by-zero.rs b/src/tools/miri/tests/fail/intrinsics/simd-div-by-zero.rs
new file mode 100644
index 000000000000..5fa6f69d0059
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-div-by-zero.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    pub(crate) fn simd_div<T>(x: T, y: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(1, 1);
+        let y = i32x2(1, 0);
+        simd_div(x, y); //~ERROR: Undefined Behavior: dividing by zero
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-div-by-zero.stderr b/src/tools/miri/tests/fail/intrinsics/simd-div-by-zero.stderr
new file mode 100644
index 000000000000..ddab24d0c163
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-div-by-zero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dividing by zero
+  --> $DIR/simd-div-by-zero.rs:LL:CC
+   |
+LL |         simd_div(x, y);
+   |         ^^^^^^^^^^^^^^ dividing by zero
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-div-by-zero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-div-overflow.rs b/src/tools/miri/tests/fail/intrinsics/simd-div-overflow.rs
new file mode 100644
index 000000000000..57712b1b836b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-div-overflow.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    pub(crate) fn simd_div<T>(x: T, y: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(1, i32::MIN);
+        let y = i32x2(1, -1);
+        simd_div(x, y); //~ERROR: Undefined Behavior: overflow in signed division
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-div-overflow.stderr b/src/tools/miri/tests/fail/intrinsics/simd-div-overflow.stderr
new file mode 100644
index 000000000000..27d4dd9e3e73
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-div-overflow.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow in signed division (dividing MIN by -1)
+  --> $DIR/simd-div-overflow.rs:LL:CC
+   |
+LL |         simd_div(x, y);
+   |         ^^^^^^^^^^^^^^ overflow in signed division (dividing MIN by -1)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-div-overflow.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-float-to-int.rs b/src/tools/miri/tests/fail/intrinsics/simd-float-to-int.rs
new file mode 100644
index 000000000000..a5bae36d92a4
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-float-to-int.rs
@@ -0,0 +1,9 @@
+//@error-pattern: cannot be represented in target type `i32`
+#![feature(portable_simd)]
+use std::simd::*;
+
+fn main() {
+    unsafe {
+        let _x: i32x2 = f32x2::from_array([f32::MAX, f32::MIN]).to_int_unchecked();
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-float-to-int.stderr b/src/tools/miri/tests/fail/intrinsics/simd-float-to-int.stderr
new file mode 100644
index 000000000000..36bb9643b48d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-float-to-int.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: `float_to_int_unchecked` intrinsic called on 3.40282347E+38 which cannot be represented in target type `i32`
+  --> RUSTLIB/core/src/../../portable-simd/crates/core_simd/src/vector.rs:LL:CC
+   |
+LL |         unsafe { intrinsics::simd_cast(self) }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^ `float_to_int_unchecked` intrinsic called on 3.40282347E+38 which cannot be represented in target type `i32`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::simd::Simd::<f32, 2>::to_int_unchecked::<i32>` at RUSTLIB/core/src/../../portable-simd/crates/core_simd/src/vector.rs:LL:CC
+note: inside `main` at $DIR/simd-float-to-int.rs:LL:CC
+  --> $DIR/simd-float-to-int.rs:LL:CC
+   |
+LL |         let _x: i32x2 = f32x2::from_array([f32::MAX, f32::MIN]).to_int_unchecked();
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-gather.rs b/src/tools/miri/tests/fail/intrinsics/simd-gather.rs
new file mode 100644
index 000000000000..e394cce9a4fe
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-gather.rs
@@ -0,0 +1,11 @@
+//@error-pattern: pointer to 1 byte starting at offset 9 is out-of-bounds
+#![feature(portable_simd)]
+use std::simd::*;
+
+fn main() {
+    unsafe {
+        let vec: &[i8] = &[10, 11, 12, 13, 14, 15, 16, 17, 18];
+        let idxs = Simd::from_array([9, 3, 0, 17]);
+        let _result = Simd::gather_select_unchecked(&vec, Mask::splat(true), idxs, Simd::splat(0));
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-gather.stderr b/src/tools/miri/tests/fail/intrinsics/simd-gather.stderr
new file mode 100644
index 000000000000..29a4ef65705a
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-gather.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 9, so pointer to 1 byte starting at offset 9 is out-of-bounds
+  --> RUSTLIB/core/src/../../portable-simd/crates/core_simd/src/vector.rs:LL:CC
+   |
+LL |         unsafe { intrinsics::simd_gather(or, ptrs, enable.to_int()) }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 9, so pointer to 1 byte starting at offset 9 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::simd::Simd::<i8, 4>::gather_select_unchecked` at RUSTLIB/core/src/../../portable-simd/crates/core_simd/src/vector.rs:LL:CC
+note: inside `main` at $DIR/simd-gather.rs:LL:CC
+  --> $DIR/simd-gather.rs:LL:CC
+   |
+LL |         let _result = Simd::gather_select_unchecked(&vec, Mask::splat(true), idxs, Simd::splat(0));
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-reduce-invalid-bool.rs b/src/tools/miri/tests/fail/intrinsics/simd-reduce-invalid-bool.rs
new file mode 100644
index 000000000000..354f8213120a
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-reduce-invalid-bool.rs
@@ -0,0 +1,16 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    pub(crate) fn simd_reduce_any<T>(x: T) -> bool;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(0, 1);
+        simd_reduce_any(x); //~ERROR: must be all-0-bits or all-1-bits
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-reduce-invalid-bool.stderr b/src/tools/miri/tests/fail/intrinsics/simd-reduce-invalid-bool.stderr
new file mode 100644
index 000000000000..1e5ac5277e6d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-reduce-invalid-bool.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: each element of a SIMD mask must be all-0-bits or all-1-bits
+  --> $DIR/simd-reduce-invalid-bool.rs:LL:CC
+   |
+LL |         simd_reduce_any(x);
+   |         ^^^^^^^^^^^^^^^^^^ each element of a SIMD mask must be all-0-bits or all-1-bits
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-reduce-invalid-bool.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-rem-by-zero.rs b/src/tools/miri/tests/fail/intrinsics/simd-rem-by-zero.rs
new file mode 100644
index 000000000000..625889bb67b5
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-rem-by-zero.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    pub(crate) fn simd_rem<T>(x: T, y: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(1, 1);
+        let y = i32x2(1, 0);
+        simd_rem(x, y); //~ERROR: Undefined Behavior: calculating the remainder with a divisor of zero
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-rem-by-zero.stderr b/src/tools/miri/tests/fail/intrinsics/simd-rem-by-zero.stderr
new file mode 100644
index 000000000000..96248e7e599c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-rem-by-zero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: calculating the remainder with a divisor of zero
+  --> $DIR/simd-rem-by-zero.rs:LL:CC
+   |
+LL |         simd_rem(x, y);
+   |         ^^^^^^^^^^^^^^ calculating the remainder with a divisor of zero
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-rem-by-zero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-scatter.rs b/src/tools/miri/tests/fail/intrinsics/simd-scatter.rs
new file mode 100644
index 000000000000..d2bc73399548
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-scatter.rs
@@ -0,0 +1,15 @@
+//@error-pattern: pointer to 1 byte starting at offset 9 is out-of-bounds
+#![feature(portable_simd)]
+use std::simd::*;
+
+fn main() {
+    unsafe {
+        let mut vec: Vec<i8> = vec![10, 11, 12, 13, 14, 15, 16, 17, 18];
+        let idxs = Simd::from_array([9, 3, 0, 17]);
+        Simd::from_array([-27, 82, -41, 124]).scatter_select_unchecked(
+            &mut vec,
+            Mask::splat(true),
+            idxs,
+        );
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-scatter.stderr b/src/tools/miri/tests/fail/intrinsics/simd-scatter.stderr
new file mode 100644
index 000000000000..fde85a63503b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-scatter.stderr
@@ -0,0 +1,24 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 9, so pointer to 1 byte starting at offset 9 is out-of-bounds
+  --> RUSTLIB/core/src/../../portable-simd/crates/core_simd/src/vector.rs:LL:CC
+   |
+LL |             intrinsics::simd_scatter(self, ptrs, enable.to_int())
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 9, so pointer to 1 byte starting at offset 9 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::simd::Simd::<i8, 4>::scatter_select_unchecked` at RUSTLIB/core/src/../../portable-simd/crates/core_simd/src/vector.rs:LL:CC
+note: inside `main` at $DIR/simd-scatter.rs:LL:CC
+  --> $DIR/simd-scatter.rs:LL:CC
+   |
+LL | /         Simd::from_array([-27, 82, -41, 124]).scatter_select_unchecked(
+LL | |             &mut vec,
+LL | |             Mask::splat(true),
+LL | |             idxs,
+LL | |         );
+   | |_________^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-select-bitmask-invalid.rs b/src/tools/miri/tests/fail/intrinsics/simd-select-bitmask-invalid.rs
new file mode 100644
index 000000000000..8a3895ac14cf
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-select-bitmask-invalid.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    fn simd_select_bitmask<M, T>(m: M, yes: T, no: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+#[derive(Copy, Clone)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(0, 1);
+        simd_select_bitmask(0b11111111u8, x, x); //~ERROR: bitmask less than 8 bits long must be filled with 0s for the remaining bits
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-select-bitmask-invalid.stderr b/src/tools/miri/tests/fail/intrinsics/simd-select-bitmask-invalid.stderr
new file mode 100644
index 000000000000..e72cce998d0e
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-select-bitmask-invalid.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: a SIMD bitmask less than 8 bits long must be filled with 0s for the remaining bits
+  --> $DIR/simd-select-bitmask-invalid.rs:LL:CC
+   |
+LL |         simd_select_bitmask(0b11111111u8, x, x);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ a SIMD bitmask less than 8 bits long must be filled with 0s for the remaining bits
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-select-bitmask-invalid.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-select-invalid-bool.rs b/src/tools/miri/tests/fail/intrinsics/simd-select-invalid-bool.rs
new file mode 100644
index 000000000000..7f7ee3af4951
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-select-invalid-bool.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    fn simd_select<M, T>(m: M, yes: T, no: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+#[derive(Copy, Clone)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(0, 1);
+        simd_select(x, x, x); //~ERROR: must be all-0-bits or all-1-bits
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-select-invalid-bool.stderr b/src/tools/miri/tests/fail/intrinsics/simd-select-invalid-bool.stderr
new file mode 100644
index 000000000000..277ceb54ec71
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-select-invalid-bool.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: each element of a SIMD mask must be all-0-bits or all-1-bits
+  --> $DIR/simd-select-invalid-bool.rs:LL:CC
+   |
+LL |         simd_select(x, x, x);
+   |         ^^^^^^^^^^^^^^^^^^^^ each element of a SIMD mask must be all-0-bits or all-1-bits
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-select-invalid-bool.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-shl-too-far.rs b/src/tools/miri/tests/fail/intrinsics/simd-shl-too-far.rs
new file mode 100644
index 000000000000..5c517c17b3a4
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-shl-too-far.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    pub(crate) fn simd_shl<T>(x: T, y: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(1, 1);
+        let y = i32x2(100, 0);
+        simd_shl(x, y); //~ERROR: overflowing shift by 100 in `simd_shl` in SIMD lane 0
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-shl-too-far.stderr b/src/tools/miri/tests/fail/intrinsics/simd-shl-too-far.stderr
new file mode 100644
index 000000000000..c8445bb3cdc7
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-shl-too-far.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing shift by 100 in `simd_shl` in SIMD lane 0
+  --> $DIR/simd-shl-too-far.rs:LL:CC
+   |
+LL |         simd_shl(x, y);
+   |         ^^^^^^^^^^^^^^ overflowing shift by 100 in `simd_shl` in SIMD lane 0
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-shl-too-far.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-shr-too-far.rs b/src/tools/miri/tests/fail/intrinsics/simd-shr-too-far.rs
new file mode 100644
index 000000000000..5f1475a67781
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-shr-too-far.rs
@@ -0,0 +1,17 @@
+#![feature(platform_intrinsics, repr_simd)]
+
+extern "platform-intrinsic" {
+    pub(crate) fn simd_shr<T>(x: T, y: T) -> T;
+}
+
+#[repr(simd)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+
+fn main() {
+    unsafe {
+        let x = i32x2(1, 1);
+        let y = i32x2(20, 40);
+        simd_shr(x, y); //~ERROR: overflowing shift by 40 in `simd_shr` in SIMD lane 1
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/simd-shr-too-far.stderr b/src/tools/miri/tests/fail/intrinsics/simd-shr-too-far.stderr
new file mode 100644
index 000000000000..8eec30c5a52f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/simd-shr-too-far.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing shift by 40 in `simd_shr` in SIMD lane 1
+  --> $DIR/simd-shr-too-far.rs:LL:CC
+   |
+LL |         simd_shr(x, y);
+   |         ^^^^^^^^^^^^^^ overflowing shift by 40 in `simd_shr` in SIMD lane 1
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/simd-shr-too-far.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_add1.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_add1.rs
new file mode 100644
index 000000000000..13265d0fb0ee
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_add1.rs
@@ -0,0 +1,6 @@
+#![feature(unchecked_math)]
+
+fn main() {
+    // MAX overflow
+    let _val = unsafe { 40000u16.unchecked_add(30000) }; //~ ERROR: overflow executing `unchecked_add`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_add1.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_add1.stderr
new file mode 100644
index 000000000000..f5e96198ee4c
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_add1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow executing `unchecked_add`
+  --> $DIR/unchecked_add1.rs:LL:CC
+   |
+LL |     let _val = unsafe { 40000u16.unchecked_add(30000) };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_add`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_add1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_add2.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_add2.rs
new file mode 100644
index 000000000000..229f50321d7d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_add2.rs
@@ -0,0 +1,6 @@
+#![feature(unchecked_math)]
+
+fn main() {
+    // MIN overflow
+    let _val = unsafe { (-30000i16).unchecked_add(-8000) }; //~ ERROR: overflow executing `unchecked_add`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_add2.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_add2.stderr
new file mode 100644
index 000000000000..5a5c7070ae0b
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_add2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow executing `unchecked_add`
+  --> $DIR/unchecked_add2.rs:LL:CC
+   |
+LL |     let _val = unsafe { (-30000i16).unchecked_add(-8000) };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_add`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_add2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_div1.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_div1.rs
new file mode 100644
index 000000000000..6706cee30ef5
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_div1.rs
@@ -0,0 +1,7 @@
+#![feature(core_intrinsics)]
+fn main() {
+    // MIN/-1 cannot be represented
+    unsafe {
+        std::intrinsics::unchecked_div(i16::MIN, -1); //~ ERROR: overflow in signed division (dividing MIN by -1)
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_div1.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_div1.stderr
new file mode 100644
index 000000000000..9267e0c49473
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_div1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow in signed division (dividing MIN by -1)
+  --> $DIR/unchecked_div1.rs:LL:CC
+   |
+LL |         std::intrinsics::unchecked_div(i16::MIN, -1);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow in signed division (dividing MIN by -1)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_div1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_mul1.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_mul1.rs
new file mode 100644
index 000000000000..810d3418dc8f
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_mul1.rs
@@ -0,0 +1,5 @@
+#![feature(unchecked_math)]
+fn main() {
+    // MAX overflow
+    let _val = unsafe { 300u16.unchecked_mul(250u16) }; //~ ERROR: overflow executing `unchecked_mul`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_mul1.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_mul1.stderr
new file mode 100644
index 000000000000..9a5a585e1cce
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_mul1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow executing `unchecked_mul`
+  --> $DIR/unchecked_mul1.rs:LL:CC
+   |
+LL |     let _val = unsafe { 300u16.unchecked_mul(250u16) };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_mul`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_mul1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_mul2.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_mul2.rs
new file mode 100644
index 000000000000..421019542a95
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_mul2.rs
@@ -0,0 +1,5 @@
+#![feature(unchecked_math)]
+fn main() {
+    // MIN overflow
+    let _val = unsafe { 1_000_000_000i32.unchecked_mul(-4) }; //~ ERROR: overflow executing `unchecked_mul`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_mul2.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_mul2.stderr
new file mode 100644
index 000000000000..46b9f6182172
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_mul2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow executing `unchecked_mul`
+  --> $DIR/unchecked_mul2.rs:LL:CC
+   |
+LL |     let _val = unsafe { 1_000_000_000i32.unchecked_mul(-4) };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_mul`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_mul2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_sub1.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_sub1.rs
new file mode 100644
index 000000000000..c6e006667441
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_sub1.rs
@@ -0,0 +1,5 @@
+#![feature(unchecked_math)]
+fn main() {
+    // MIN overflow
+    let _val = unsafe { 14u32.unchecked_sub(22) }; //~ ERROR: overflow executing `unchecked_sub`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_sub1.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_sub1.stderr
new file mode 100644
index 000000000000..01e569767bac
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_sub1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow executing `unchecked_sub`
+  --> $DIR/unchecked_sub1.rs:LL:CC
+   |
+LL |     let _val = unsafe { 14u32.unchecked_sub(22) };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_sub`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_sub1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_sub2.rs b/src/tools/miri/tests/fail/intrinsics/unchecked_sub2.rs
new file mode 100644
index 000000000000..65aa292e212d
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_sub2.rs
@@ -0,0 +1,5 @@
+#![feature(unchecked_math)]
+fn main() {
+    // MAX overflow
+    let _val = unsafe { 30000i16.unchecked_sub(-7000) }; //~ ERROR: overflow executing `unchecked_sub`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/unchecked_sub2.stderr b/src/tools/miri/tests/fail/intrinsics/unchecked_sub2.stderr
new file mode 100644
index 000000000000..38c1647b4f49
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/unchecked_sub2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow executing `unchecked_sub`
+  --> $DIR/unchecked_sub2.rs:LL:CC
+   |
+LL |     let _val = unsafe { 30000i16.unchecked_sub(-7000) };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow executing `unchecked_sub`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unchecked_sub2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.rs b/src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.rs
new file mode 100644
index 000000000000..e606d8b283c8
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.rs
@@ -0,0 +1,7 @@
+#![feature(never_type)]
+
+#[allow(deprecated, invalid_value)]
+fn main() {
+    unsafe { std::mem::uninitialized::<!>() };
+    //~^ ERROR: attempted to instantiate uninhabited type `!`
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.stderr b/src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.stderr
new file mode 100644
index 000000000000..150128ba2a41
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/uninit_uninhabited_type.stderr
@@ -0,0 +1,12 @@
+error: abnormal termination: aborted execution: attempted to instantiate uninhabited type `!`
+  --> $DIR/uninit_uninhabited_type.rs:LL:CC
+   |
+LL |     unsafe { std::mem::uninitialized::<!>() };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to instantiate uninhabited type `!`
+   |
+   = note: inside `main` at $DIR/uninit_uninhabited_type.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/write_bytes_null.rs b/src/tools/miri/tests/fail/intrinsics/write_bytes_null.rs
new file mode 100644
index 000000000000..2f46c820fb73
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/write_bytes_null.rs
@@ -0,0 +1,10 @@
+#![feature(intrinsics)]
+
+// Directly call intrinsic to avoid debug assertions in libstd
+extern "rust-intrinsic" {
+    fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
+}
+
+fn main() {
+    unsafe { write_bytes::<u8>(std::ptr::null_mut(), 0, 0) }; //~ ERROR: memory access failed: null pointer is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/write_bytes_null.stderr b/src/tools/miri/tests/fail/intrinsics/write_bytes_null.stderr
new file mode 100644
index 000000000000..b2969ca3b592
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/write_bytes_null.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: memory access failed: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/write_bytes_null.rs:LL:CC
+   |
+LL |     unsafe { write_bytes::<u8>(std::ptr::null_mut(), 0, 0) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/write_bytes_null.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/write_bytes_overflow.rs b/src/tools/miri/tests/fail/intrinsics/write_bytes_overflow.rs
new file mode 100644
index 000000000000..08bc096d6c36
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/write_bytes_overflow.rs
@@ -0,0 +1,9 @@
+use std::mem;
+
+fn main() {
+    let mut y = 0;
+    unsafe {
+        (&mut y as *mut i32).write_bytes(0u8, 1usize << (mem::size_of::<usize>() * 8 - 1));
+        //~^ ERROR: overflow computing total size of `write_bytes`
+    }
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/write_bytes_overflow.stderr b/src/tools/miri/tests/fail/intrinsics/write_bytes_overflow.stderr
new file mode 100644
index 000000000000..f88afde879ac
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/write_bytes_overflow.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflow computing total size of `write_bytes`
+  --> $DIR/write_bytes_overflow.rs:LL:CC
+   |
+LL |         (&mut y as *mut i32).write_bytes(0u8, 1usize << (mem::size_of::<usize>() * 8 - 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow computing total size of `write_bytes`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/write_bytes_overflow.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.rs b/src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.rs
new file mode 100644
index 000000000000..6d9ae14c5c47
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.rs
@@ -0,0 +1,5 @@
+#[allow(deprecated, invalid_value)]
+fn main() {
+    unsafe { std::mem::zeroed::<fn()>() };
+    //~^ ERROR: attempted to zero-initialize type `fn()`, which is invalid
+}
diff --git a/src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.stderr b/src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.stderr
new file mode 100644
index 000000000000..9d44ba9f746a
--- /dev/null
+++ b/src/tools/miri/tests/fail/intrinsics/zero_fn_ptr.stderr
@@ -0,0 +1,12 @@
+error: abnormal termination: aborted execution: attempted to zero-initialize type `fn()`, which is invalid
+  --> $DIR/zero_fn_ptr.rs:LL:CC
+   |
+LL |     unsafe { std::mem::zeroed::<fn()>() };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to zero-initialize type `fn()`, which is invalid
+   |
+   = note: inside `main` at $DIR/zero_fn_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/invalid_bool.rs b/src/tools/miri/tests/fail/invalid_bool.rs
new file mode 100644
index 000000000000..525f8831c1c0
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_bool.rs
@@ -0,0 +1,9 @@
+// Validation makes this fail in the wrong place
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+#![feature(bench_black_box)]
+
+fn main() {
+    let b = unsafe { std::mem::transmute::<u8, bool>(2) };
+    let _x = b == std::hint::black_box(true); //~ ERROR: interpreting an invalid 8-bit value as a bool
+}
diff --git a/src/tools/miri/tests/fail/invalid_bool.stderr b/src/tools/miri/tests/fail/invalid_bool.stderr
new file mode 100644
index 000000000000..a522f6cd4fff
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_bool.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: interpreting an invalid 8-bit value as a bool: 0x02
+  --> $DIR/invalid_bool.rs:LL:CC
+   |
+LL |     let _x = b == std::hint::black_box(true);
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ interpreting an invalid 8-bit value as a bool: 0x02
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_bool.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/invalid_char.rs b/src/tools/miri/tests/fail/invalid_char.rs
new file mode 100644
index 000000000000..699248229445
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_char.rs
@@ -0,0 +1,10 @@
+// Validation makes this fail in the wrong place
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+fn main() {
+    let c = 0xFFFFFFu32;
+    assert!(std::char::from_u32(c).is_none());
+    let c = unsafe { std::mem::transmute::<u32, char>(c) };
+    let _x = c == 'x'; //~ ERROR: interpreting an invalid 32-bit value as a char
+}
diff --git a/src/tools/miri/tests/fail/invalid_char.stderr b/src/tools/miri/tests/fail/invalid_char.stderr
new file mode 100644
index 000000000000..d49d753d9e18
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_char.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: interpreting an invalid 32-bit value as a char: $HEX
+  --> $DIR/invalid_char.rs:LL:CC
+   |
+LL |     let _x = c == 'x';
+   |              ^^^^^^^^ interpreting an invalid 32-bit value as a char: $HEX
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_char.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/invalid_enum_tag.rs b/src/tools/miri/tests/fail/invalid_enum_tag.rs
new file mode 100644
index 000000000000..84fa2c297390
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_enum_tag.rs
@@ -0,0 +1,18 @@
+// Validation makes this fail in the wrong place
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+use std::mem;
+
+#[repr(C)]
+pub enum Foo {
+    A,
+    B,
+    C,
+    D,
+}
+
+fn main() {
+    let f = unsafe { std::mem::transmute::<i32, Foo>(42) };
+    let _val = mem::discriminant(&f); //~ERROR: enum value has invalid tag
+}
diff --git a/src/tools/miri/tests/fail/invalid_enum_tag.stderr b/src/tools/miri/tests/fail/invalid_enum_tag.stderr
new file mode 100644
index 000000000000..01d931de919a
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_enum_tag.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: enum value has invalid tag: $HEX
+  --> $DIR/invalid_enum_tag.rs:LL:CC
+   |
+LL |     let _val = mem::discriminant(&f);
+   |                ^^^^^^^^^^^^^^^^^^^^^ enum value has invalid tag: $HEX
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_enum_tag.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/invalid_int.rs b/src/tools/miri/tests/fail/invalid_int.rs
new file mode 100644
index 000000000000..2435a87a6f28
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_int.rs
@@ -0,0 +1,9 @@
+#![allow(invalid_value)]
+// Validation makes this fail in the wrong place
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+fn main() {
+    let i = unsafe { std::mem::MaybeUninit::<i32>::uninit().assume_init() }; //~ ERROR: uninitialized
+    let _x = i + 0;
+}
diff --git a/src/tools/miri/tests/fail/invalid_int.stderr b/src/tools/miri/tests/fail/invalid_int.stderr
new file mode 100644
index 000000000000..eccdbff60457
--- /dev/null
+++ b/src/tools/miri/tests/fail/invalid_int.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/invalid_int.rs:LL:CC
+   |
+LL |     let i = unsafe { std::mem::MaybeUninit::<i32>::uninit().assume_init() };
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_int.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/issue-miri-1112.rs b/src/tools/miri/tests/fail/issue-miri-1112.rs
new file mode 100644
index 000000000000..387253a3f987
--- /dev/null
+++ b/src/tools/miri/tests/fail/issue-miri-1112.rs
@@ -0,0 +1,42 @@
+trait Empty {}
+
+#[repr(transparent)]
+pub struct FunnyPointer(dyn Empty);
+
+#[repr(C)]
+pub struct Meta {
+    drop_fn: fn(&mut ()),
+    size: usize,
+    align: usize,
+}
+
+impl Meta {
+    pub fn new() -> Self {
+        Meta { drop_fn: |_| {}, size: 0, align: 1 }
+    }
+}
+
+#[repr(C)]
+pub struct FatPointer {
+    pub data: *const (),
+    pub vtable: *const (),
+}
+
+impl FunnyPointer {
+    pub unsafe fn from_data_ptr(data: &String, ptr: *const Meta) -> &Self {
+        let obj = FatPointer {
+            data: data as *const _ as *const (),
+            vtable: ptr as *const _ as *const (),
+        };
+        let obj = std::mem::transmute::<FatPointer, *mut FunnyPointer>(obj); //~ ERROR: expected a vtable pointer
+        &*obj
+    }
+}
+
+fn main() {
+    unsafe {
+        let meta = Meta::new();
+        let hello = "hello".to_string();
+        let _raw: &FunnyPointer = FunnyPointer::from_data_ptr(&hello, &meta as *const _);
+    }
+}
diff --git a/src/tools/miri/tests/fail/issue-miri-1112.stderr b/src/tools/miri/tests/fail/issue-miri-1112.stderr
new file mode 100644
index 000000000000..e6644a72849f
--- /dev/null
+++ b/src/tools/miri/tests/fail/issue-miri-1112.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: constructing invalid value: encountered $HEX[ALLOC]<TAG>, but expected a vtable pointer
+  --> $DIR/issue-miri-1112.rs:LL:CC
+   |
+LL |         let obj = std::mem::transmute::<FatPointer, *mut FunnyPointer>(obj);
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered $HEX[ALLOC]<TAG>, but expected a vtable pointer
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `FunnyPointer::from_data_ptr` at $DIR/issue-miri-1112.rs:LL:CC
+note: inside `main` at $DIR/issue-miri-1112.rs:LL:CC
+  --> $DIR/issue-miri-1112.rs:LL:CC
+   |
+LL |         let _raw: &FunnyPointer = FunnyPointer::from_data_ptr(&hello, &meta as *const _);
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/issue-miri-2432.rs b/src/tools/miri/tests/fail/issue-miri-2432.rs
new file mode 100644
index 000000000000..f822479c4368
--- /dev/null
+++ b/src/tools/miri/tests/fail/issue-miri-2432.rs
@@ -0,0 +1,19 @@
+#![allow(where_clauses_object_safety)]
+
+trait Trait {}
+
+trait X {
+    fn foo(&self)
+    where
+        Self: Trait;
+}
+
+impl X for () {
+    fn foo(&self) {}
+}
+
+impl Trait for dyn X {}
+
+pub fn main() {
+    <dyn X as X>::foo(&()); //~ERROR: trying to call something that is not a method
+}
diff --git a/src/tools/miri/tests/fail/issue-miri-2432.stderr b/src/tools/miri/tests/fail/issue-miri-2432.stderr
new file mode 100644
index 000000000000..b8e13b61ceb6
--- /dev/null
+++ b/src/tools/miri/tests/fail/issue-miri-2432.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: `dyn` call trying to call something that is not a method
+  --> $DIR/issue-miri-2432.rs:LL:CC
+   |
+LL |     <dyn X as X>::foo(&());
+   |     ^^^^^^^^^^^^^^^^^^^^^^ `dyn` call trying to call something that is not a method
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/issue-miri-2432.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/memleak.rs b/src/tools/miri/tests/fail/memleak.rs
new file mode 100644
index 000000000000..d384caf81a57
--- /dev/null
+++ b/src/tools/miri/tests/fail/memleak.rs
@@ -0,0 +1,6 @@
+//@error-pattern: the evaluated program leaked memory
+//@normalize-stderr-test: ".*│.*" -> "$$stripped$$"
+
+fn main() {
+    std::mem::forget(Box::new(42));
+}
diff --git a/src/tools/miri/tests/fail/memleak.stderr b/src/tools/miri/tests/fail/memleak.stderr
new file mode 100644
index 000000000000..f8b62af3eb85
--- /dev/null
+++ b/src/tools/miri/tests/fail/memleak.stderr
@@ -0,0 +1,10 @@
+The following memory was leaked: ALLOC (Rust heap, size: 4, align: 4) {
+$stripped$
+}
+
+error: the evaluated program leaked memory
+
+note: pass `-Zmiri-ignore-leaks` to disable this check
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/memleak_rc.32bit.stderr b/src/tools/miri/tests/fail/memleak_rc.32bit.stderr
new file mode 100644
index 000000000000..da222609091a
--- /dev/null
+++ b/src/tools/miri/tests/fail/memleak_rc.32bit.stderr
@@ -0,0 +1,10 @@
+The following memory was leaked: ALLOC (Rust heap, size: 16, align: 4) {
+$stripped$
+}
+
+error: the evaluated program leaked memory
+
+note: pass `-Zmiri-ignore-leaks` to disable this check
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/memleak_rc.64bit.stderr b/src/tools/miri/tests/fail/memleak_rc.64bit.stderr
new file mode 100644
index 000000000000..8c24bbc779bd
--- /dev/null
+++ b/src/tools/miri/tests/fail/memleak_rc.64bit.stderr
@@ -0,0 +1,11 @@
+The following memory was leaked: ALLOC (Rust heap, size: 32, align: 8) {
+$stripped$
+$stripped$
+}
+
+error: the evaluated program leaked memory
+
+note: pass `-Zmiri-ignore-leaks` to disable this check
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/memleak_rc.rs b/src/tools/miri/tests/fail/memleak_rc.rs
new file mode 100644
index 000000000000..76ecd71b011a
--- /dev/null
+++ b/src/tools/miri/tests/fail/memleak_rc.rs
@@ -0,0 +1,14 @@
+//@error-pattern: the evaluated program leaked memory
+//@stderr-per-bitwidth
+//@normalize-stderr-test: ".*│.*" -> "$$stripped$$"
+
+use std::cell::RefCell;
+use std::rc::Rc;
+
+struct Dummy(Rc<RefCell<Option<Dummy>>>);
+
+fn main() {
+    let x = Dummy(Rc::new(RefCell::new(None)));
+    let y = Dummy(x.0.clone());
+    *x.0.borrow_mut() = Some(y);
+}
diff --git a/src/tools/miri/tests/fail/memleak_rc.stderr b/src/tools/miri/tests/fail/memleak_rc.stderr
new file mode 100644
index 000000000000..290de49c82c0
--- /dev/null
+++ b/src/tools/miri/tests/fail/memleak_rc.stderr
@@ -0,0 +1,11 @@
+The following memory was leaked: ALLOC (Rust heap, size: 32, align: 8) {
+    0x00 │ 01 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 │ ................
+    0x10 │ 00 00 00 00 00 00 00 00 ╾$HEX[a1765]<TAG>─╼ │ ........╾──────╼
+}
+
+error: the evaluated program leaked memory
+
+note: pass `-Zmiri-ignore-leaks` to disable this check
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/modifying_constants.rs b/src/tools/miri/tests/fail/modifying_constants.rs
new file mode 100644
index 000000000000..2783ebd155ff
--- /dev/null
+++ b/src/tools/miri/tests/fail/modifying_constants.rs
@@ -0,0 +1,9 @@
+// This should fail even without validation/SB
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+fn main() {
+    let x = &1; // the `&1` is promoted to a constant, but it used to be that only the pointer is marked static, not the pointee
+    let y = unsafe { &mut *(x as *const i32 as *mut i32) };
+    *y = 42; //~ ERROR: read-only
+    assert_eq!(*x, 42);
+}
diff --git a/src/tools/miri/tests/fail/modifying_constants.stderr b/src/tools/miri/tests/fail/modifying_constants.stderr
new file mode 100644
index 000000000000..6425a5d7a0ad
--- /dev/null
+++ b/src/tools/miri/tests/fail/modifying_constants.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: writing to ALLOC which is read-only
+  --> $DIR/modifying_constants.rs:LL:CC
+   |
+LL |     *y = 42;
+   |     ^^^^^^^ writing to ALLOC which is read-only
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/modifying_constants.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/never_say_never.rs b/src/tools/miri/tests/fail/never_say_never.rs
new file mode 100644
index 000000000000..f6d3dc790bf0
--- /dev/null
+++ b/src/tools/miri/tests/fail/never_say_never.rs
@@ -0,0 +1,17 @@
+// This should fail even without validation
+//@compile-flags: -Zmiri-disable-validation
+
+#![feature(never_type)]
+#![allow(unreachable_code)]
+
+fn main() {
+    let y = &5;
+    let x: ! = unsafe {
+        *(y as *const _ as *const !) //~ ERROR: entering unreachable code
+    };
+    f(x)
+}
+
+fn f(x: !) -> ! {
+    x
+}
diff --git a/src/tools/miri/tests/fail/never_say_never.stderr b/src/tools/miri/tests/fail/never_say_never.stderr
new file mode 100644
index 000000000000..a2a63b8baf59
--- /dev/null
+++ b/src/tools/miri/tests/fail/never_say_never.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: entering unreachable code
+  --> $DIR/never_say_never.rs:LL:CC
+   |
+LL |         *(y as *const _ as *const !)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ entering unreachable code
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/never_say_never.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/never_transmute_humans.rs b/src/tools/miri/tests/fail/never_transmute_humans.rs
new file mode 100644
index 000000000000..de723433dc28
--- /dev/null
+++ b/src/tools/miri/tests/fail/never_transmute_humans.rs
@@ -0,0 +1,12 @@
+// This should fail even without validation
+//@compile-flags: -Zmiri-disable-validation
+
+#![feature(never_type)]
+
+struct Human;
+
+fn main() {
+    let _x: ! = unsafe {
+        std::mem::transmute::<Human, !>(Human) //~ ERROR: transmuting to uninhabited
+    };
+}
diff --git a/src/tools/miri/tests/fail/never_transmute_humans.stderr b/src/tools/miri/tests/fail/never_transmute_humans.stderr
new file mode 100644
index 000000000000..e8df4739f9bc
--- /dev/null
+++ b/src/tools/miri/tests/fail/never_transmute_humans.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: transmuting to uninhabited type
+  --> $DIR/never_transmute_humans.rs:LL:CC
+   |
+LL |         std::mem::transmute::<Human, !>(Human)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/never_transmute_humans.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/never_transmute_void.rs b/src/tools/miri/tests/fail/never_transmute_void.rs
new file mode 100644
index 000000000000..19473e9ac214
--- /dev/null
+++ b/src/tools/miri/tests/fail/never_transmute_void.rs
@@ -0,0 +1,20 @@
+// This should fail even without validation
+//@compile-flags: -Zmiri-disable-validation
+//@require-annotations-for-level: ERROR
+
+#![feature(never_type)]
+#![allow(unused, invalid_value)]
+
+mod m {
+    enum VoidI {}
+    pub struct Void(VoidI);
+
+    pub fn f(v: Void) -> ! {
+        match v.0 {} //~ ERROR: entering unreachable code
+    }
+}
+
+fn main() {
+    let v = unsafe { std::mem::transmute::<(), m::Void>(()) };
+    m::f(v); //~ NOTE: inside `main`
+}
diff --git a/src/tools/miri/tests/fail/never_transmute_void.stderr b/src/tools/miri/tests/fail/never_transmute_void.stderr
new file mode 100644
index 000000000000..4c3a3d075f02
--- /dev/null
+++ b/src/tools/miri/tests/fail/never_transmute_void.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: entering unreachable code
+  --> $DIR/never_transmute_void.rs:LL:CC
+   |
+LL |         match v.0 {}
+   |               ^^^ entering unreachable code
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `m::f` at $DIR/never_transmute_void.rs:LL:CC
+note: inside `main` at $DIR/never_transmute_void.rs:LL:CC
+  --> $DIR/never_transmute_void.rs:LL:CC
+   |
+LL |     m::f(v);
+   |     ^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/no_main.rs b/src/tools/miri/tests/fail/no_main.rs
new file mode 100644
index 000000000000..e28205040871
--- /dev/null
+++ b/src/tools/miri/tests/fail/no_main.rs
@@ -0,0 +1,2 @@
+//@error-pattern: miri can only run programs that have a main function
+#![no_main]
diff --git a/src/tools/miri/tests/fail/no_main.stderr b/src/tools/miri/tests/fail/no_main.stderr
new file mode 100644
index 000000000000..88bdfb4e387c
--- /dev/null
+++ b/src/tools/miri/tests/fail/no_main.stderr
@@ -0,0 +1,4 @@
+error: miri can only run programs that have a main function
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/bad_miri_start_panic.rs b/src/tools/miri/tests/fail/panic/bad_miri_start_panic.rs
new file mode 100644
index 000000000000..4b0ae60b1010
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/bad_miri_start_panic.rs
@@ -0,0 +1,12 @@
+//@compile-flags: -Zmiri-disable-abi-check
+// This feature is required to trigger the error using the "C" ABI.
+#![feature(c_unwind)]
+
+extern "C" {
+    fn miri_start_panic(payload: *mut u8) -> !;
+}
+
+fn main() {
+    unsafe { miri_start_panic(&mut 0) }
+    //~^ ERROR: unwinding past a stack frame that does not allow unwinding
+}
diff --git a/src/tools/miri/tests/fail/panic/bad_miri_start_panic.stderr b/src/tools/miri/tests/fail/panic/bad_miri_start_panic.stderr
new file mode 100644
index 000000000000..3bd2be03ea1f
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/bad_miri_start_panic.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
+  --> $DIR/bad_miri_start_panic.rs:LL:CC
+   |
+LL |     unsafe { miri_start_panic(&mut 0) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^ unwinding past a stack frame that does not allow unwinding
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad_miri_start_panic.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/bad_unwind.rs b/src/tools/miri/tests/fail/panic/bad_unwind.rs
new file mode 100644
index 000000000000..370b372a7d37
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/bad_unwind.rs
@@ -0,0 +1,14 @@
+#![feature(c_unwind)]
+
+//! Unwinding when the caller ABI is "C" (without "-unwind") is UB.
+
+extern "C-unwind" fn unwind() {
+    panic!();
+}
+
+fn main() {
+    let unwind: extern "C-unwind" fn() = unwind;
+    let unwind: extern "C" fn() = unsafe { std::mem::transmute(unwind) };
+    std::panic::catch_unwind(|| unwind()).unwrap_err();
+    //~^ ERROR: unwinding past a stack frame that does not allow unwinding
+}
diff --git a/src/tools/miri/tests/fail/panic/bad_unwind.stderr b/src/tools/miri/tests/fail/panic/bad_unwind.stderr
new file mode 100644
index 000000000000..23c33f5e7f3f
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/bad_unwind.stderr
@@ -0,0 +1,25 @@
+thread 'main' panicked at 'explicit panic', $DIR/bad_unwind.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
+  --> $DIR/bad_unwind.rs:LL:CC
+   |
+LL |     std::panic::catch_unwind(|| unwind()).unwrap_err();
+   |                                 ^^^^^^^^ unwinding past a stack frame that does not allow unwinding
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/bad_unwind.rs:LL:CC
+   = note: inside `std::panicking::r#try::do_call::<[closure@$DIR/bad_unwind.rs:LL:CC], ()>` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::panicking::r#try::<(), [closure@$DIR/bad_unwind.rs:LL:CC]>` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::panic::catch_unwind::<[closure@$DIR/bad_unwind.rs:LL:CC], ()>` at RUSTLIB/std/src/panic.rs:LL:CC
+note: inside `main` at $DIR/bad_unwind.rs:LL:CC
+  --> $DIR/bad_unwind.rs:LL:CC
+   |
+LL |     std::panic::catch_unwind(|| unwind()).unwrap_err();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/double_panic.rs b/src/tools/miri/tests/fail/panic/double_panic.rs
new file mode 100644
index 000000000000..8919d51bb2f7
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/double_panic.rs
@@ -0,0 +1,14 @@
+//@error-pattern: the program aborted
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "unsafe \{ libc::abort\(\) \}|crate::intrinsics::abort\(\);" -> "ABORT();"
+
+struct Foo;
+impl Drop for Foo {
+    fn drop(&mut self) {
+        panic!("second");
+    }
+}
+fn main() {
+    let _foo = Foo;
+    panic!("first");
+}
diff --git a/src/tools/miri/tests/fail/panic/double_panic.stderr b/src/tools/miri/tests/fail/panic/double_panic.stderr
new file mode 100644
index 000000000000..f1d2b4de97cc
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/double_panic.stderr
@@ -0,0 +1,94 @@
+thread 'main' panicked at 'first', $DIR/double_panic.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+thread 'main' panicked at 'second', $DIR/double_panic.rs:LL:CC
+stack backtrace:
+   0: std::backtrace_rs::backtrace::miri::trace_unsynchronized
+ at RUSTLIB/std/src/../../backtrace/src/backtrace/miri.rs:LL:CC
+   1: std::backtrace_rs::backtrace::miri::trace
+ at RUSTLIB/std/src/../../backtrace/src/backtrace/miri.rs:LL:CC
+   2: std::backtrace_rs::backtrace::trace_unsynchronized
+ at RUSTLIB/std/src/../../backtrace/src/backtrace/mod.rs:LL:CC
+   3: std::sys_common::backtrace::_print_fmt
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   4: <std::sys_common::backtrace::_print::DisplayBacktrace as std::fmt::Display>::fmt
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   5: std::fmt::write
+ at RUSTLIB/core/src/fmt/mod.rs:LL:CC
+   6: <std::sys::PLATFORM::stdio::Stderr as std::io::Write>::write_fmt
+ at RUSTLIB/std/src/io/mod.rs:LL:CC
+   7: std::sys_common::backtrace::_print
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   8: std::sys_common::backtrace::print
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   9: std::panicking::default_hook::{closure#1}
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  10: std::panicking::default_hook
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  11: std::panicking::rust_panic_with_hook
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  12: std::rt::begin_panic::{closure#0}
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  13: std::sys_common::backtrace::__rust_end_short_backtrace
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+  14: std::rt::begin_panic
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  15: <Foo as std::ops::Drop>::drop
+ at $DIR/double_panic.rs:LL:CC
+  16: std::ptr::drop_in_place - shim(Some(Foo))
+ at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+  17: main
+ at $DIR/double_panic.rs:LL:CC
+  18: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+  19: std::sys_common::backtrace::__rust_begin_short_backtrace
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+  20: std::rt::lang_start::{closure#0}
+ at RUSTLIB/std/src/rt.rs:LL:CC
+  21: std::ops::function::impls::call_once
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+  22: std::panicking::r#try::do_call
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  23: std::panicking::r#try
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  24: std::panic::catch_unwind
+ at RUSTLIB/std/src/panic.rs:LL:CC
+  25: std::rt::lang_start_internal::{closure#2}
+ at RUSTLIB/std/src/rt.rs:LL:CC
+  26: std::panicking::r#try::do_call
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  27: std::panicking::r#try
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  28: std::panic::catch_unwind
+ at RUSTLIB/std/src/panic.rs:LL:CC
+  29: std::rt::lang_start_internal
+ at RUSTLIB/std/src/rt.rs:LL:CC
+  30: std::rt::lang_start
+ at RUSTLIB/std/src/rt.rs:LL:CC
+thread panicked while panicking. aborting.
+error: abnormal termination: the program aborted execution
+  --> RUSTLIB/std/src/sys/PLATFORM/mod.rs:LL:CC
+   |
+LL |     ABORT();
+   | ^ the program aborted execution
+   |
+   = note: inside `std::sys::PLATFORM::abort_internal` at RUSTLIB/std/src/sys/PLATFORM/mod.rs:LL:CC
+   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::rt::begin_panic<&str>::{closure#0}], !>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+note: inside `<Foo as std::ops::Drop>::drop` at RUSTLIB/std/src/panic.rs:LL:CC
+  --> $DIR/double_panic.rs:LL:CC
+   |
+LL |         panic!("second");
+   | ^
+   = note: inside `std::ptr::drop_in_place::<Foo> - shim(Some(Foo))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+note: inside `main` at $DIR/double_panic.rs:LL:CC
+  --> $DIR/double_panic.rs:LL:CC
+   |
+LL | }
+   | ^
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/panic_abort1.rs b/src/tools/miri/tests/fail/panic/panic_abort1.rs
new file mode 100644
index 000000000000..00a01ce6e813
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort1.rs
@@ -0,0 +1,8 @@
+//@error-pattern: the program aborted execution
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "libc::abort\(\);|core::intrinsics::abort\(\);" -> "ABORT();"
+//@compile-flags: -C panic=abort
+
+fn main() {
+    std::panic!("panicking from libstd");
+}
diff --git a/src/tools/miri/tests/fail/panic/panic_abort1.stderr b/src/tools/miri/tests/fail/panic/panic_abort1.stderr
new file mode 100644
index 000000000000..754719945464
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort1.stderr
@@ -0,0 +1,25 @@
+thread 'main' panicked at 'panicking from libstd', $DIR/panic_abort1.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   |
+LL |                 ABORT();
+   | ^ the program aborted execution
+   |
+   = note: inside `panic_abort::__rust_start_panic::abort` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `panic_abort::__rust_start_panic` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `std::panicking::rust_panic` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::rt::begin_panic<&str>::{closure#0}], !>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+note: inside `main` at RUSTLIB/std/src/panic.rs:LL:CC
+  --> $DIR/panic_abort1.rs:LL:CC
+   |
+LL |     std::panic!("panicking from libstd");
+   | ^
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `std::panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/panic_abort2.rs b/src/tools/miri/tests/fail/panic/panic_abort2.rs
new file mode 100644
index 000000000000..dee0de96703a
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort2.rs
@@ -0,0 +1,8 @@
+//@error-pattern: the program aborted execution
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "libc::abort\(\);|core::intrinsics::abort\(\);" -> "ABORT();"
+//@compile-flags: -C panic=abort
+
+fn main() {
+    std::panic!("{}-panicking from libstd", 42);
+}
diff --git a/src/tools/miri/tests/fail/panic/panic_abort2.stderr b/src/tools/miri/tests/fail/panic/panic_abort2.stderr
new file mode 100644
index 000000000000..2fdf889d798a
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort2.stderr
@@ -0,0 +1,26 @@
+thread 'main' panicked at '42-panicking from libstd', $DIR/panic_abort2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   |
+LL |                 ABORT();
+   | ^ the program aborted execution
+   |
+   = note: inside `panic_abort::__rust_start_panic::abort` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `panic_abort::__rust_start_panic` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `std::panicking::rust_panic` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::panicking::begin_panic_handler::{closure#0}], !>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
+note: inside `main` at RUSTLIB/std/src/panic.rs:LL:CC
+  --> $DIR/panic_abort2.rs:LL:CC
+   |
+LL |     std::panic!("{}-panicking from libstd", 42);
+   | ^
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `std::panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/panic_abort3.rs b/src/tools/miri/tests/fail/panic/panic_abort3.rs
new file mode 100644
index 000000000000..a448aab3ea45
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort3.rs
@@ -0,0 +1,8 @@
+//@error-pattern: the program aborted execution
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "libc::abort\(\);|core::intrinsics::abort\(\);" -> "ABORT();"
+//@compile-flags: -C panic=abort
+
+fn main() {
+    core::panic!("panicking from libcore");
+}
diff --git a/src/tools/miri/tests/fail/panic/panic_abort3.stderr b/src/tools/miri/tests/fail/panic/panic_abort3.stderr
new file mode 100644
index 000000000000..8704b0d940b7
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort3.stderr
@@ -0,0 +1,26 @@
+thread 'main' panicked at 'panicking from libcore', $DIR/panic_abort3.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   |
+LL |                 ABORT();
+   | ^ the program aborted execution
+   |
+   = note: inside `panic_abort::__rust_start_panic::abort` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `panic_abort::__rust_start_panic` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `std::panicking::rust_panic` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::panicking::begin_panic_handler::{closure#0}], !>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
+note: inside `main` at RUSTLIB/core/src/panic.rs:LL:CC
+  --> $DIR/panic_abort3.rs:LL:CC
+   |
+LL |     core::panic!("panicking from libcore");
+   | ^
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `core::panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/panic_abort4.rs b/src/tools/miri/tests/fail/panic/panic_abort4.rs
new file mode 100644
index 000000000000..4995dad9d71a
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort4.rs
@@ -0,0 +1,8 @@
+//@error-pattern: the program aborted execution
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "libc::abort\(\);|core::intrinsics::abort\(\);" -> "ABORT();"
+//@compile-flags: -C panic=abort
+
+fn main() {
+    core::panic!("{}-panicking from libcore", 42);
+}
diff --git a/src/tools/miri/tests/fail/panic/panic_abort4.stderr b/src/tools/miri/tests/fail/panic/panic_abort4.stderr
new file mode 100644
index 000000000000..1d75d72c0317
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/panic_abort4.stderr
@@ -0,0 +1,26 @@
+thread 'main' panicked at '42-panicking from libcore', $DIR/panic_abort4.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+error: abnormal termination: the program aborted execution
+  --> RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   |
+LL |                 ABORT();
+   | ^ the program aborted execution
+   |
+   = note: inside `panic_abort::__rust_start_panic::abort` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `panic_abort::__rust_start_panic` at RUSTLIB/panic_abort/src/lib.rs:LL:CC
+   = note: inside `std::panicking::rust_panic` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::panicking::begin_panic_handler::{closure#0}], !>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
+note: inside `main` at RUSTLIB/core/src/panic.rs:LL:CC
+  --> $DIR/panic_abort4.rs:LL:CC
+   |
+LL |     core::panic!("{}-panicking from libcore", 42);
+   | ^
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `core::panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/panic/unwind_panic_abort.rs b/src/tools/miri/tests/fail/panic/unwind_panic_abort.rs
new file mode 100644
index 000000000000..c21fa85a9043
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/unwind_panic_abort.rs
@@ -0,0 +1,13 @@
+//@compile-flags: -Cpanic=abort
+
+//! Unwinding despite `-C panic=abort` is an error.
+
+extern "Rust" {
+    fn miri_start_panic(payload: *mut u8) -> !;
+}
+
+fn main() {
+    unsafe {
+        miri_start_panic(&mut 0); //~ ERROR: unwinding past a stack frame that does not allow unwinding
+    }
+}
diff --git a/src/tools/miri/tests/fail/panic/unwind_panic_abort.stderr b/src/tools/miri/tests/fail/panic/unwind_panic_abort.stderr
new file mode 100644
index 000000000000..363e69ba41db
--- /dev/null
+++ b/src/tools/miri/tests/fail/panic/unwind_panic_abort.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
+  --> $DIR/unwind_panic_abort.rs:LL:CC
+   |
+LL |         miri_start_panic(&mut 0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^ unwinding past a stack frame that does not allow unwinding
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unwind_panic_abort.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/pointer_partial_overwrite.rs b/src/tools/miri/tests/fail/pointer_partial_overwrite.rs
new file mode 100644
index 000000000000..63f0649b8ed3
--- /dev/null
+++ b/src/tools/miri/tests/fail/pointer_partial_overwrite.rs
@@ -0,0 +1,17 @@
+// Make sure we find these even with many checks disabled.
+//@compile-flags: -Zmiri-disable-alignment-check -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+// Test what happens when we overwrite parts of a pointer.
+// Also see <https://github.com/rust-lang/miri/issues/2181>.
+
+fn main() {
+    let mut p = &42;
+    unsafe {
+        let ptr: *mut _ = &mut p;
+        *(ptr as *mut u8) = 123; // if we ever support 8 bit pointers, this is gonna cause
+        // "attempted to interpret some raw bytes as a pointer address" instead of
+        // "attempted to read undefined bytes"
+    }
+    let x = *p; //~ ERROR: this operation requires initialized memory
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/pointer_partial_overwrite.stderr b/src/tools/miri/tests/fail/pointer_partial_overwrite.stderr
new file mode 100644
index 000000000000..7d10b75e8805
--- /dev/null
+++ b/src/tools/miri/tests/fail/pointer_partial_overwrite.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/pointer_partial_overwrite.rs:LL:CC
+   |
+LL |     let x = *p;
+   |             ^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/pointer_partial_overwrite.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/provenance/provenance_transmute.rs b/src/tools/miri/tests/fail/provenance/provenance_transmute.rs
new file mode 100644
index 000000000000..abcfc060e52b
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/provenance_transmute.rs
@@ -0,0 +1,27 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(strict_provenance)]
+
+use std::mem;
+
+// This is the example from
+// <https://github.com/rust-lang/unsafe-code-guidelines/issues/286#issuecomment-1085144431>.
+
+unsafe fn deref(left: *const u8, right: *const u8) {
+    let left_int: usize = mem::transmute(left);
+    let right_int: usize = mem::transmute(right);
+    if left_int == right_int {
+        // The compiler is allowed to replace `left_int` by `right_int` here...
+        let left_ptr: *const u8 = mem::transmute(left_int);
+        // ...which however means here it could be dereferencing the wrong pointer.
+        let _val = *left_ptr; //~ERROR: dereferencing pointer failed
+    }
+}
+
+fn main() {
+    let ptr1 = &0u8 as *const u8;
+    let ptr2 = &1u8 as *const u8;
+    unsafe {
+        // Two pointers with the same address but different provenance.
+        deref(ptr1, ptr2.with_addr(ptr1.addr()));
+    }
+}
diff --git a/src/tools/miri/tests/fail/provenance/provenance_transmute.stderr b/src/tools/miri/tests/fail/provenance/provenance_transmute.stderr
new file mode 100644
index 000000000000..f7c5f6046e19
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/provenance_transmute.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/provenance_transmute.rs:LL:CC
+   |
+LL |         let _val = *left_ptr;
+   |                    ^^^^^^^^^ dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `deref` at $DIR/provenance_transmute.rs:LL:CC
+note: inside `main` at $DIR/provenance_transmute.rs:LL:CC
+  --> $DIR/provenance_transmute.rs:LL:CC
+   |
+LL |         deref(ptr1, ptr2.with_addr(ptr1.addr()));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/provenance/ptr_int_unexposed.rs b/src/tools/miri/tests/fail/provenance/ptr_int_unexposed.rs
new file mode 100644
index 000000000000..07de41d10a03
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/ptr_int_unexposed.rs
@@ -0,0 +1,12 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(strict_provenance)]
+
+fn main() {
+    let x: i32 = 3;
+    let x_ptr = &x as *const i32;
+
+    let x_usize: usize = x_ptr.addr();
+    // Cast back an address that did *not* get exposed.
+    let ptr = std::ptr::from_exposed_addr::<i32>(x_usize);
+    assert_eq!(unsafe { *ptr }, 3); //~ ERROR: is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/provenance/ptr_int_unexposed.stderr b/src/tools/miri/tests/fail/provenance/ptr_int_unexposed.stderr
new file mode 100644
index 000000000000..4ad885ddabdc
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/ptr_int_unexposed.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/ptr_int_unexposed.rs:LL:CC
+   |
+LL |     assert_eq!(unsafe { *ptr }, 3);
+   |                         ^^^^ dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_int_unexposed.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/provenance/ptr_invalid.rs b/src/tools/miri/tests/fail/provenance/ptr_invalid.rs
new file mode 100644
index 000000000000..d7d32d83e077
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/ptr_invalid.rs
@@ -0,0 +1,9 @@
+#![feature(strict_provenance)]
+
+// Ensure that a `ptr::invalid` ptr is truly invalid.
+fn main() {
+    let x = 42;
+    let xptr = &x as *const i32;
+    let xptr_invalid = std::ptr::invalid::<i32>(xptr.expose_addr());
+    let _val = unsafe { *xptr_invalid }; //~ ERROR: is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/provenance/ptr_invalid.stderr b/src/tools/miri/tests/fail/provenance/ptr_invalid.stderr
new file mode 100644
index 000000000000..ef9dcad97cbd
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/ptr_invalid.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/ptr_invalid.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xptr_invalid };
+   |                         ^^^^^^^^^^^^^ dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_invalid.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/provenance/ptr_invalid_offset.rs b/src/tools/miri/tests/fail/provenance/ptr_invalid_offset.rs
new file mode 100644
index 000000000000..91ba18f76805
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/ptr_invalid_offset.rs
@@ -0,0 +1,10 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(strict_provenance)]
+
+fn main() {
+    let x = 22;
+    let ptr = &x as *const _ as *const u8;
+    let roundtrip = std::ptr::invalid::<u8>(ptr as usize);
+    // Not even offsetting this is allowed.
+    let _ = unsafe { roundtrip.offset(1) }; //~ERROR: is a dangling pointer
+}
diff --git a/src/tools/miri/tests/fail/provenance/ptr_invalid_offset.stderr b/src/tools/miri/tests/fail/provenance/ptr_invalid_offset.stderr
new file mode 100644
index 000000000000..3607635c8fbe
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/ptr_invalid_offset.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer arithmetic: $HEX[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/ptr_invalid_offset.rs:LL:CC
+   |
+LL |     let _ = unsafe { roundtrip.offset(1) };
+   |                      ^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer arithmetic: $HEX[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_invalid_offset.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/provenance/strict_provenance_cast.rs b/src/tools/miri/tests/fail/provenance/strict_provenance_cast.rs
new file mode 100644
index 000000000000..04552d0c332f
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/strict_provenance_cast.rs
@@ -0,0 +1,7 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(strict_provenance)]
+
+fn main() {
+    let addr = &0 as *const i32 as usize;
+    let _ptr = std::ptr::from_exposed_addr::<i32>(addr); //~ ERROR: integer-to-pointer casts and `ptr::from_exposed_addr` are not supported
+}
diff --git a/src/tools/miri/tests/fail/provenance/strict_provenance_cast.stderr b/src/tools/miri/tests/fail/provenance/strict_provenance_cast.stderr
new file mode 100644
index 000000000000..998ccc8bb49c
--- /dev/null
+++ b/src/tools/miri/tests/fail/provenance/strict_provenance_cast.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`
+  --> $DIR/strict_provenance_cast.rs:LL:CC
+   |
+LL |     let _ptr = std::ptr::from_exposed_addr::<i32>(addr);
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`
+   |
+   = help: use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/strict_provenance_cast.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/rc_as_ptr.rs b/src/tools/miri/tests/fail/rc_as_ptr.rs
new file mode 100644
index 000000000000..6aea1870748c
--- /dev/null
+++ b/src/tools/miri/tests/fail/rc_as_ptr.rs
@@ -0,0 +1,20 @@
+// This should fail even without validation
+//@compile-flags: -Zmiri-disable-validation
+
+use std::ptr;
+use std::rc::{Rc, Weak};
+
+/// Taken from the `Weak::as_ptr` doctest.
+fn main() {
+    let strong = Rc::new(Box::new(42));
+    let weak = Rc::downgrade(&strong);
+    // Both point to the same object
+    assert!(ptr::eq(&*strong, Weak::as_ptr(&weak)));
+    // The strong here keeps it alive, so we can still access the object.
+    assert_eq!(42, **unsafe { &*Weak::as_ptr(&weak) });
+
+    drop(strong);
+    // But not any more. We can do Weak::as_raw(&weak), but accessing the pointer would lead to
+    // undefined behaviour.
+    assert_eq!(42, **unsafe { &*Weak::as_ptr(&weak) }); //~ ERROR: dereferenced after this allocation got freed
+}
diff --git a/src/tools/miri/tests/fail/rc_as_ptr.stderr b/src/tools/miri/tests/fail/rc_as_ptr.stderr
new file mode 100644
index 000000000000..70bdd157bdc3
--- /dev/null
+++ b/src/tools/miri/tests/fail/rc_as_ptr.stderr
@@ -0,0 +1,16 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/rc_as_ptr.rs:LL:CC
+   |
+LL |     assert_eq!(42, **unsafe { &*Weak::as_ptr(&weak) });
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at RUSTLIB/core/src/macros/mod.rs:LL:CC
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/reading_half_a_pointer.rs b/src/tools/miri/tests/fail/reading_half_a_pointer.rs
new file mode 100644
index 000000000000..2d6691326247
--- /dev/null
+++ b/src/tools/miri/tests/fail/reading_half_a_pointer.rs
@@ -0,0 +1,30 @@
+#![allow(dead_code)]
+
+// We use packed structs to get around alignment restrictions
+#[repr(packed)]
+struct Data {
+    pad: u8,
+    ptr: &'static i32,
+}
+
+// But we need to gurantee some alignment
+struct Wrapper {
+    align: u64,
+    data: Data,
+}
+
+static G: i32 = 0;
+
+fn main() {
+    let mut w = Wrapper { align: 0, data: Data { pad: 0, ptr: &G } };
+
+    // Get a pointer to the beginning of the Data struct (one u8 byte, then the pointer bytes).
+    // Thanks to the wrapper, we know this is aligned-enough to perform a load at ptr size.
+    // We load at pointer type, so having a relocation is ok -- but here, the relocation
+    // starts 1 byte to the right, so using it would actually be wrong!
+    let d_alias = &mut w.data as *mut _ as *mut *const u8;
+    unsafe {
+        let x = *d_alias;
+        let _val = *x; //~ERROR: is a dangling pointer (it has no provenance)
+    }
+}
diff --git a/src/tools/miri/tests/fail/reading_half_a_pointer.stderr b/src/tools/miri/tests/fail/reading_half_a_pointer.stderr
new file mode 100644
index 000000000000..61a7161a98bb
--- /dev/null
+++ b/src/tools/miri/tests/fail/reading_half_a_pointer.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+  --> $DIR/reading_half_a_pointer.rs:LL:CC
+   |
+LL |         let _val = *x;
+   |                    ^^ dereferencing pointer failed: $HEX[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/reading_half_a_pointer.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/rustc-error.rs b/src/tools/miri/tests/fail/rustc-error.rs
new file mode 100644
index 000000000000..7fc73bf365d5
--- /dev/null
+++ b/src/tools/miri/tests/fail/rustc-error.rs
@@ -0,0 +1,4 @@
+// Make sure we exit with non-0 status code when the program fails to build.
+fn main() {
+    println("Hello, world!"); //~ ERROR: expected function, found macro
+}
diff --git a/src/tools/miri/tests/fail/rustc-error.stderr b/src/tools/miri/tests/fail/rustc-error.stderr
new file mode 100644
index 000000000000..09d0f7a6df95
--- /dev/null
+++ b/src/tools/miri/tests/fail/rustc-error.stderr
@@ -0,0 +1,14 @@
+error[E0423]: expected function, found macro `println`
+  --> $DIR/rustc-error.rs:LL:CC
+   |
+LL |     println("Hello, world!");
+   |     ^^^^^^^ not a function
+   |
+help: use `!` to invoke the macro
+   |
+LL |     println!("Hello, world!");
+   |            +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0423`.
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-decl.rs b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-decl.rs
new file mode 100644
index 000000000000..97a70103e646
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-decl.rs
@@ -0,0 +1,13 @@
+extern "Rust" {
+    fn miri_get_backtrace(flags: u64) -> Box<[*mut ()]>;
+    fn miri_resolve_frame(ptr: *mut (), flags: u64);
+}
+
+fn main() {
+    let frames = unsafe { miri_get_backtrace(0) };
+    for frame in frames.into_iter() {
+        unsafe {
+            miri_resolve_frame(*frame, 0); //~ ERROR: Undefined Behavior: bad declaration of miri_resolve_frame - should return a struct with 5 fields
+        }
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-decl.stderr b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-decl.stderr
new file mode 100644
index 000000000000..200f5f56213d
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-decl.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: bad declaration of miri_resolve_frame - should return a struct with 5 fields
+  --> $DIR/bad-backtrace-decl.rs:LL:CC
+   |
+LL | ...   miri_resolve_frame(*frame, 0);
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ bad declaration of miri_resolve_frame - should return a struct with 5 fields
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad-backtrace-decl.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-flags.rs b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-flags.rs
new file mode 100644
index 000000000000..a4e186eaa98a
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-flags.rs
@@ -0,0 +1,9 @@
+extern "Rust" {
+    fn miri_get_backtrace(flags: u64, buf: *mut *mut ());
+}
+
+fn main() {
+    unsafe {
+        miri_get_backtrace(2, std::ptr::null_mut()); //~ ERROR:  unsupported operation: unknown `miri_get_backtrace` flags 2
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-flags.stderr b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-flags.stderr
new file mode 100644
index 000000000000..5d51790f8a5c
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-flags.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: unknown `miri_get_backtrace` flags 2
+  --> $DIR/bad-backtrace-flags.rs:LL:CC
+   |
+LL |         miri_get_backtrace(2, std::ptr::null_mut());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unknown `miri_get_backtrace` flags 2
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad-backtrace-flags.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-ptr.rs b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-ptr.rs
new file mode 100644
index 000000000000..843d0d11873d
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-ptr.rs
@@ -0,0 +1,9 @@
+extern "Rust" {
+    fn miri_resolve_frame(ptr: *mut (), flags: u64);
+}
+
+fn main() {
+    unsafe {
+        miri_resolve_frame(std::ptr::null_mut(), 0); //~ ERROR: null pointer is a dangling pointer
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-ptr.stderr b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-ptr.stderr
new file mode 100644
index 000000000000..f23f834000aa
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: out-of-bounds pointer use: null pointer is a dangling pointer (it has no provenance)
+  --> $DIR/bad-backtrace-ptr.rs:LL:CC
+   |
+LL |         miri_resolve_frame(std::ptr::null_mut(), 0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: null pointer is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad-backtrace-ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-flags.rs b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-flags.rs
new file mode 100644
index 000000000000..31e3915f3d64
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-flags.rs
@@ -0,0 +1,25 @@
+#[repr(C)]
+struct MiriFrame {
+    name_len: usize,
+    filename_len: usize,
+    lineno: u32,
+    colno: u32,
+    fn_ptr: *mut (),
+}
+
+extern "Rust" {
+    fn miri_backtrace_size(flags: u64) -> usize;
+    fn miri_get_backtrace(flags: u64, buf: *mut *mut ());
+    fn miri_resolve_frame(ptr: *mut (), flags: u64) -> MiriFrame;
+}
+
+fn main() {
+    unsafe {
+        let mut buf = vec![std::ptr::null_mut(); miri_backtrace_size(0)];
+
+        miri_get_backtrace(1, buf.as_mut_ptr());
+
+        // miri_resolve_frame will error from an invalid backtrace before it will from invalid flags
+        miri_resolve_frame(buf[0], 2); //~ ERROR:  unsupported operation: unknown `miri_resolve_frame` flags 2
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-flags.stderr b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-flags.stderr
new file mode 100644
index 000000000000..fe123c2352f0
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-flags.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: unknown `miri_resolve_frame` flags 2
+  --> $DIR/bad-backtrace-resolve-flags.rs:LL:CC
+   |
+LL |         miri_resolve_frame(buf[0], 2);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unknown `miri_resolve_frame` flags 2
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad-backtrace-resolve-flags.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-names-flags.rs b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-names-flags.rs
new file mode 100644
index 000000000000..44c3c025043b
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-names-flags.rs
@@ -0,0 +1,16 @@
+extern "Rust" {
+    fn miri_backtrace_size(flags: u64) -> usize;
+    fn miri_get_backtrace(flags: u64, buf: *mut *mut ());
+    fn miri_resolve_frame_names(ptr: *mut (), flags: u64, name_buf: *mut u8, filename_buf: *mut u8);
+}
+
+fn main() {
+    unsafe {
+        let mut buf = vec![std::ptr::null_mut(); miri_backtrace_size(0)];
+
+        miri_get_backtrace(1, buf.as_mut_ptr());
+
+        // miri_resolve_frame_names will error from an invalid backtrace before it will from invalid flags
+        miri_resolve_frame_names(buf[0], 2, std::ptr::null_mut(), std::ptr::null_mut()); //~ ERROR:  unsupported operation: unknown `miri_resolve_frame_names` flags 2
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-names-flags.stderr b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-names-flags.stderr
new file mode 100644
index 000000000000..a3003c9093f7
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-resolve-names-flags.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: unknown `miri_resolve_frame_names` flags 2
+  --> $DIR/bad-backtrace-resolve-names-flags.rs:LL:CC
+   |
+LL | ...   miri_resolve_frame_names(buf[0], 2, std::ptr::null_mut(), std::ptr::null_mut());
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unknown `miri_resolve_frame_names` flags 2
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad-backtrace-resolve-names-flags.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-size-flags.rs b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-size-flags.rs
new file mode 100644
index 000000000000..bba74c71a5e8
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-size-flags.rs
@@ -0,0 +1,9 @@
+extern "Rust" {
+    fn miri_backtrace_size(flags: u64) -> usize;
+}
+
+fn main() {
+    unsafe {
+        miri_backtrace_size(2); //~ ERROR:  unsupported operation: unknown `miri_backtrace_size` flags 2
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-size-flags.stderr b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-size-flags.stderr
new file mode 100644
index 000000000000..b4a02c0e363e
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/backtrace/bad-backtrace-size-flags.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: unknown `miri_backtrace_size` flags 2
+  --> $DIR/bad-backtrace-size-flags.rs:LL:CC
+   |
+LL |         miri_backtrace_size(2);
+   |         ^^^^^^^^^^^^^^^^^^^^^^ unknown `miri_backtrace_size` flags 2
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/bad-backtrace-size-flags.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/close_stdout.rs b/src/tools/miri/tests/fail/shims/fs/close_stdout.rs
new file mode 100644
index 000000000000..09da8509af41
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/close_stdout.rs
@@ -0,0 +1,10 @@
+//@ignore-target-windows: No libc on Windows
+//@compile-flags: -Zmiri-disable-isolation
+
+// FIXME: standard handles cannot be closed (https://github.com/rust-lang/rust/issues/40032)
+
+fn main() {
+    unsafe {
+        libc::close(1); //~ ERROR: cannot close stdout
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/close_stdout.stderr b/src/tools/miri/tests/fail/shims/fs/close_stdout.stderr
new file mode 100644
index 000000000000..02f1eee97fc0
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/close_stdout.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: cannot close stdout
+  --> $DIR/close_stdout.rs:LL:CC
+   |
+LL |         libc::close(1);
+   |         ^^^^^^^^^^^^^^ cannot close stdout
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/close_stdout.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/isolated_file.rs b/src/tools/miri/tests/fail/shims/fs/isolated_file.rs
new file mode 100644
index 000000000000..9b664ffe52ac
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/isolated_file.rs
@@ -0,0 +1,6 @@
+//@ignore-target-windows: File handling is not implemented yet
+//@error-pattern: `open` not available when isolation is enabled
+
+fn main() {
+    let _file = std::fs::File::open("file.txt").unwrap();
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr b/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr
new file mode 100644
index 000000000000..4e3fdc7a4580
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/isolated_file.stderr
@@ -0,0 +1,26 @@
+error: unsupported operation: `open` not available when isolation is enabled
+  --> RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
+   |
+LL |         let fd = cvt_r(|| unsafe { open64(path.as_ptr(), flags, opts.mode as c_int) })?;
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `open` not available when isolation is enabled
+   |
+   = help: pass the flag `-Zmiri-disable-isolation` to disable isolation;
+   = help: or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning
+   = note: BACKTRACE:
+   = note: inside closure at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
+   = note: inside `std::sys::PLATFORM::cvt_r::<i32, [closure@std::sys::PLATFORM::fs::File::open_c::{closure#0}]>` at RUSTLIB/std/src/sys/PLATFORM/mod.rs:LL:CC
+   = note: inside `std::sys::PLATFORM::fs::File::open_c` at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
+   = note: inside `std::sys::PLATFORM::fs::File::open` at RUSTLIB/std/src/sys/PLATFORM/fs.rs:LL:CC
+   = note: inside `std::fs::OpenOptions::_open` at RUSTLIB/std/src/fs.rs:LL:CC
+   = note: inside `std::fs::OpenOptions::open::<&std::path::Path>` at RUSTLIB/std/src/fs.rs:LL:CC
+   = note: inside `std::fs::File::open::<&str>` at RUSTLIB/std/src/fs.rs:LL:CC
+note: inside `main` at $DIR/isolated_file.rs:LL:CC
+  --> $DIR/isolated_file.rs:LL:CC
+   |
+LL |     let _file = std::fs::File::open("file.txt").unwrap();
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/isolated_stdin.rs b/src/tools/miri/tests/fail/shims/fs/isolated_stdin.rs
new file mode 100644
index 000000000000..a45f805696d4
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/isolated_stdin.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() -> std::io::Result<()> {
+    let mut bytes = [0u8; 512];
+    unsafe {
+        libc::read(0, bytes.as_mut_ptr() as *mut libc::c_void, 512); //~ ERROR: `read` from stdin not available when isolation is enabled
+    }
+    Ok(())
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/isolated_stdin.stderr b/src/tools/miri/tests/fail/shims/fs/isolated_stdin.stderr
new file mode 100644
index 000000000000..ed826147e3bd
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/isolated_stdin.stderr
@@ -0,0 +1,15 @@
+error: unsupported operation: `read` from stdin not available when isolation is enabled
+  --> $DIR/isolated_stdin.rs:LL:CC
+   |
+LL |         libc::read(0, bytes.as_mut_ptr() as *mut libc::c_void, 512);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `read` from stdin not available when isolation is enabled
+   |
+   = help: pass the flag `-Zmiri-disable-isolation` to disable isolation;
+   = help: or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/isolated_stdin.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/mkstemp_immutable_arg.rs b/src/tools/miri/tests/fail/shims/fs/mkstemp_immutable_arg.rs
new file mode 100644
index 000000000000..ba9f404d7c9a
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/mkstemp_immutable_arg.rs
@@ -0,0 +1,11 @@
+//@ignore-target-windows: No libc on Windows
+//@compile-flags: -Zmiri-disable-isolation
+
+fn main() {
+    test_mkstemp_immutable_arg();
+}
+
+fn test_mkstemp_immutable_arg() {
+    let s: *mut libc::c_char = b"fooXXXXXX\0" as *const _ as *mut _;
+    let _fd = unsafe { libc::mkstemp(s) }; //~ ERROR: Undefined Behavior: writing to alloc1 which is read-only
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/mkstemp_immutable_arg.stderr b/src/tools/miri/tests/fail/shims/fs/mkstemp_immutable_arg.stderr
new file mode 100644
index 000000000000..414ac1cb1b70
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/mkstemp_immutable_arg.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: writing to ALLOC which is read-only
+  --> $DIR/mkstemp_immutable_arg.rs:LL:CC
+   |
+LL |     let _fd = unsafe { libc::mkstemp(s) };
+   |                        ^^^^^^^^^^^^^^^^ writing to ALLOC which is read-only
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `test_mkstemp_immutable_arg` at $DIR/mkstemp_immutable_arg.rs:LL:CC
+note: inside `main` at $DIR/mkstemp_immutable_arg.rs:LL:CC
+  --> $DIR/mkstemp_immutable_arg.rs:LL:CC
+   |
+LL |     test_mkstemp_immutable_arg();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/read_from_stdout.rs b/src/tools/miri/tests/fail/shims/fs/read_from_stdout.rs
new file mode 100644
index 000000000000..073fca4712e9
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/read_from_stdout.rs
@@ -0,0 +1,10 @@
+//@compile-flags: -Zmiri-disable-isolation
+//@ignore-target-windows: No libc on Windows
+
+fn main() -> std::io::Result<()> {
+    let mut bytes = [0u8; 512];
+    unsafe {
+        libc::read(1, bytes.as_mut_ptr() as *mut libc::c_void, 512); //~ ERROR: cannot read from stdout
+    }
+    Ok(())
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/read_from_stdout.stderr b/src/tools/miri/tests/fail/shims/fs/read_from_stdout.stderr
new file mode 100644
index 000000000000..bcece7ad4e55
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/read_from_stdout.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: cannot read from stdout
+  --> $DIR/read_from_stdout.rs:LL:CC
+   |
+LL |         libc::read(1, bytes.as_mut_ptr() as *mut libc::c_void, 512);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot read from stdout
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/read_from_stdout.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/unix_open_missing_required_mode.rs b/src/tools/miri/tests/fail/shims/fs/unix_open_missing_required_mode.rs
new file mode 100644
index 000000000000..ae231d4be667
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/unix_open_missing_required_mode.rs
@@ -0,0 +1,12 @@
+//@ignore-target-windows: No libc on Windows
+//@compile-flags: -Zmiri-disable-isolation
+
+fn main() {
+    test_file_open_missing_needed_mode();
+}
+
+fn test_file_open_missing_needed_mode() {
+    let name = b"missing_arg.txt\0";
+    let name_ptr = name.as_ptr().cast::<libc::c_char>();
+    let _fd = unsafe { libc::open(name_ptr, libc::O_CREAT) }; //~ ERROR: Undefined Behavior: incorrect number of arguments for `open` with `O_CREAT`: got 2, expected at least 3
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/unix_open_missing_required_mode.stderr b/src/tools/miri/tests/fail/shims/fs/unix_open_missing_required_mode.stderr
new file mode 100644
index 000000000000..38d033b49455
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/unix_open_missing_required_mode.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: incorrect number of arguments for `open` with `O_CREAT`: got 2, expected at least 3
+  --> $DIR/unix_open_missing_required_mode.rs:LL:CC
+   |
+LL | ...safe { libc::open(name_ptr, libc::O_CREAT) };
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect number of arguments for `open` with `O_CREAT`: got 2, expected at least 3
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `test_file_open_missing_needed_mode` at $DIR/unix_open_missing_required_mode.rs:LL:CC
+note: inside `main` at $DIR/unix_open_missing_required_mode.rs:LL:CC
+  --> $DIR/unix_open_missing_required_mode.rs:LL:CC
+   |
+LL |     test_file_open_missing_needed_mode();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/fs/write_to_stdin.rs b/src/tools/miri/tests/fail/shims/fs/write_to_stdin.rs
new file mode 100644
index 000000000000..d039ad718d33
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/write_to_stdin.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() -> std::io::Result<()> {
+    let bytes = b"hello";
+    unsafe {
+        libc::write(0, bytes.as_ptr() as *const libc::c_void, 5); //~ ERROR: cannot write to stdin
+    }
+    Ok(())
+}
diff --git a/src/tools/miri/tests/fail/shims/fs/write_to_stdin.stderr b/src/tools/miri/tests/fail/shims/fs/write_to_stdin.stderr
new file mode 100644
index 000000000000..d4a38e1ca961
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/fs/write_to_stdin.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: cannot write to stdin
+  --> $DIR/write_to_stdin.rs:LL:CC
+   |
+LL |         libc::write(0, bytes.as_ptr() as *const libc::c_void, 5);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot write to stdin
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/write_to_stdin.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/shim_arg_size.rs b/src/tools/miri/tests/fail/shims/shim_arg_size.rs
new file mode 100644
index 000000000000..3d7bc25bf5d3
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/shim_arg_size.rs
@@ -0,0 +1,10 @@
+fn main() {
+    extern "C" {
+        // Use the wrong type (ie. not `i32`) for the `c` argument.
+        fn memchr(s: *const std::ffi::c_void, c: u8, n: usize) -> *mut std::ffi::c_void;
+    }
+
+    unsafe {
+        memchr(std::ptr::null(), 0, 0); //~ ERROR: Undefined Behavior: scalar size mismatch
+    };
+}
diff --git a/src/tools/miri/tests/fail/shims/shim_arg_size.stderr b/src/tools/miri/tests/fail/shims/shim_arg_size.stderr
new file mode 100644
index 000000000000..d951f81810ef
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/shim_arg_size.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: scalar size mismatch: expected 4 bytes but got 1 bytes instead
+  --> $DIR/shim_arg_size.rs:LL:CC
+   |
+LL |         memchr(std::ptr::null(), 0, 0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ scalar size mismatch: expected 4 bytes but got 1 bytes instead
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/shim_arg_size.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_cond_double_destroy.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_cond_double_destroy.rs
new file mode 100644
index 000000000000..94ca3496ed94
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_cond_double_destroy.rs
@@ -0,0 +1,20 @@
+//@ignore-target-windows: No libc on Windows
+
+/// Test that destroying a pthread_cond twice fails, even without a check for number validity
+
+fn main() {
+    unsafe {
+        use core::mem::MaybeUninit;
+        let mut attr = MaybeUninit::<libc::pthread_condattr_t>::uninit();
+        libc::pthread_condattr_init(attr.as_mut_ptr());
+
+        let mut cond = MaybeUninit::<libc::pthread_cond_t>::uninit();
+
+        libc::pthread_cond_init(cond.as_mut_ptr(), attr.as_ptr());
+
+        libc::pthread_cond_destroy(cond.as_mut_ptr());
+
+        libc::pthread_cond_destroy(cond.as_mut_ptr());
+        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_cond_double_destroy.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_cond_double_destroy.stderr
new file mode 100644
index 000000000000..ecfedf753703
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_cond_double_destroy.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/libc_pthread_cond_double_destroy.rs:LL:CC
+   |
+LL |         libc::pthread_cond_destroy(cond.as_mut_ptr());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_cond_double_destroy.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_condattr_double_destroy.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_condattr_double_destroy.rs
new file mode 100644
index 000000000000..13e639a867dc
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_condattr_double_destroy.rs
@@ -0,0 +1,17 @@
+//@ignore-target-windows: No libc on Windows
+
+/// Test that destroying a pthread_condattr twice fails, even without a check for number validity
+
+fn main() {
+    unsafe {
+        use core::mem::MaybeUninit;
+        let mut attr = MaybeUninit::<libc::pthread_condattr_t>::uninit();
+
+        libc::pthread_condattr_init(attr.as_mut_ptr());
+
+        libc::pthread_condattr_destroy(attr.as_mut_ptr());
+
+        libc::pthread_condattr_destroy(attr.as_mut_ptr());
+        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_condattr_double_destroy.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_condattr_double_destroy.stderr
new file mode 100644
index 000000000000..f39d909adbd6
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_condattr_double_destroy.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/libc_pthread_condattr_double_destroy.rs:LL:CC
+   |
+LL |         libc::pthread_condattr_destroy(attr.as_mut_ptr());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_condattr_double_destroy.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_NULL_deadlock.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_NULL_deadlock.rs
new file mode 100644
index 000000000000..8b2510733831
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_NULL_deadlock.rs
@@ -0,0 +1,12 @@
+//@ignore-target-windows: No libc on Windows
+//
+// Check that if we pass NULL attribute, then we get the default mutex type.
+
+fn main() {
+    unsafe {
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, std::ptr::null() as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        libc::pthread_mutex_lock(&mut mutex as *mut _); //~ ERROR: Undefined Behavior: trying to acquire already locked default mutex
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_NULL_deadlock.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_NULL_deadlock.stderr
new file mode 100644
index 000000000000..4a138e6f8a25
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_NULL_deadlock.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to acquire already locked default mutex
+  --> $DIR/libc_pthread_mutex_NULL_deadlock.rs:LL:CC
+   |
+LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to acquire already locked default mutex
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_mutex_NULL_deadlock.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_deadlock.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_deadlock.rs
new file mode 100644
index 000000000000..6c3cb738e299
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_deadlock.rs
@@ -0,0 +1,28 @@
+//@ignore-target-windows: No libc on Windows
+
+use std::cell::UnsafeCell;
+use std::sync::Arc;
+use std::thread;
+
+struct Mutex(UnsafeCell<libc::pthread_mutex_t>);
+
+unsafe impl Send for Mutex {}
+unsafe impl Sync for Mutex {}
+
+fn new_lock() -> Arc<Mutex> {
+    Arc::new(Mutex(UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER)))
+}
+
+fn main() {
+    unsafe {
+        let lock = new_lock();
+        assert_eq!(libc::pthread_mutex_lock(lock.0.get() as *mut _), 0);
+
+        let lock_copy = lock.clone();
+        thread::spawn(move || {
+            assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _), 0); //~ ERROR: deadlock
+        })
+        .join()
+        .unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_deadlock.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_deadlock.stderr
new file mode 100644
index 000000000000..599655a8692b
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_deadlock.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_mutex_deadlock.rs:LL:CC
+   |
+LL |             assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _), 0);
+   |                                                                            ^ the evaluated program deadlocked
+   |
+   = note: inside closure at $DIR/libc_pthread_mutex_deadlock.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_default_deadlock.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_default_deadlock.rs
new file mode 100644
index 000000000000..f443768819f9
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_default_deadlock.rs
@@ -0,0 +1,13 @@
+//@ignore-target-windows: No libc on Windows
+//
+// Check that if we do not set the mutex type, it is the default.
+
+fn main() {
+    unsafe {
+        let mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mutexattr as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        libc::pthread_mutex_lock(&mut mutex as *mut _); //~ ERROR: Undefined Behavior: trying to acquire already locked default mutex
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_default_deadlock.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_default_deadlock.stderr
new file mode 100644
index 000000000000..8aea3f5c6932
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_default_deadlock.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: trying to acquire already locked default mutex
+  --> $DIR/libc_pthread_mutex_default_deadlock.rs:LL:CC
+   |
+LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to acquire already locked default mutex
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_mutex_default_deadlock.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_destroy_locked.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_destroy_locked.rs
new file mode 100644
index 000000000000..ec3965c7574e
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_destroy_locked.rs
@@ -0,0 +1,15 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    unsafe {
+        let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        assert_eq!(
+            libc::pthread_mutexattr_settype(&mut mutexattr as *mut _, libc::PTHREAD_MUTEX_NORMAL),
+            0,
+        );
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mutexattr as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        libc::pthread_mutex_destroy(&mut mutex as *mut _); //~ ERROR: destroyed a locked mutex
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_destroy_locked.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_destroy_locked.stderr
new file mode 100644
index 000000000000..a8ab948116e1
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_destroy_locked.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: destroyed a locked mutex
+  --> $DIR/libc_pthread_mutex_destroy_locked.rs:LL:CC
+   |
+LL |         libc::pthread_mutex_destroy(&mut mutex as *mut _);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ destroyed a locked mutex
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_mutex_destroy_locked.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_double_destroy.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_double_destroy.rs
new file mode 100644
index 000000000000..622c3eaeae30
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_double_destroy.rs
@@ -0,0 +1,21 @@
+//@ignore-target-windows: No libc on Windows
+
+/// Test that destroying a pthread_mutex twice fails, even without a check for number validity
+
+fn main() {
+    unsafe {
+        use core::mem::MaybeUninit;
+
+        let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
+        libc::pthread_mutexattr_init(attr.as_mut_ptr());
+
+        let mut mutex = MaybeUninit::<libc::pthread_mutex_t>::uninit();
+
+        libc::pthread_mutex_init(mutex.as_mut_ptr(), attr.as_ptr());
+
+        libc::pthread_mutex_destroy(mutex.as_mut_ptr());
+
+        libc::pthread_mutex_destroy(mutex.as_mut_ptr());
+        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_double_destroy.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_double_destroy.stderr
new file mode 100644
index 000000000000..9620fdbd18b2
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_double_destroy.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/libc_pthread_mutex_double_destroy.rs:LL:CC
+   |
+LL |         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_mutex_double_destroy.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_deadlock.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_deadlock.rs
new file mode 100644
index 000000000000..5ea09fa5aac3
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_deadlock.rs
@@ -0,0 +1,15 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    unsafe {
+        let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        assert_eq!(
+            libc::pthread_mutexattr_settype(&mut mutexattr as *mut _, libc::PTHREAD_MUTEX_NORMAL),
+            0,
+        );
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mutexattr as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        libc::pthread_mutex_lock(&mut mutex as *mut _); //~ ERROR: deadlock: the evaluated program deadlocked
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_deadlock.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_deadlock.stderr
new file mode 100644
index 000000000000..b7877d3aa397
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_deadlock.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_mutex_normal_deadlock.rs:LL:CC
+   |
+LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program deadlocked
+   |
+   = note: inside `main` at $DIR/libc_pthread_mutex_normal_deadlock.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_unlock_unlocked.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_unlock_unlocked.rs
new file mode 100644
index 000000000000..8ce7542edb87
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_unlock_unlocked.rs
@@ -0,0 +1,16 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    unsafe {
+        let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        assert_eq!(
+            libc::pthread_mutexattr_settype(&mut mutexattr as *mut _, libc::PTHREAD_MUTEX_NORMAL),
+            0,
+        );
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mutexattr as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        libc::pthread_mutex_unlock(&mut mutex as *mut _); //~ ERROR: was not locked
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_unlock_unlocked.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_unlock_unlocked.stderr
new file mode 100644
index 000000000000..754137b85b9a
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_normal_unlock_unlocked.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unlocked a PTHREAD_MUTEX_NORMAL mutex that was not locked by the current thread
+  --> $DIR/libc_pthread_mutex_normal_unlock_unlocked.rs:LL:CC
+   |
+LL |         libc::pthread_mutex_unlock(&mut mutex as *mut _);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked a PTHREAD_MUTEX_NORMAL mutex that was not locked by the current thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_mutex_normal_unlock_unlocked.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_wrong_owner.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_wrong_owner.rs
new file mode 100644
index 000000000000..b56775252e4b
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_wrong_owner.rs
@@ -0,0 +1,28 @@
+//@ignore-target-windows: No libc on Windows
+
+use std::cell::UnsafeCell;
+use std::sync::Arc;
+use std::thread;
+
+struct Mutex(UnsafeCell<libc::pthread_mutex_t>);
+
+unsafe impl Send for Mutex {}
+unsafe impl Sync for Mutex {}
+
+fn new_lock() -> Arc<Mutex> {
+    Arc::new(Mutex(UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER)))
+}
+
+fn main() {
+    unsafe {
+        let lock = new_lock();
+        assert_eq!(libc::pthread_mutex_lock(lock.0.get() as *mut _), 0);
+
+        let lock_copy = lock.clone();
+        thread::spawn(move || {
+            assert_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0); //~ ERROR: Undefined Behavior: unlocked a default mutex that was not locked by the current thread
+        })
+        .join()
+        .unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_wrong_owner.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_wrong_owner.stderr
new file mode 100644
index 000000000000..aa81b06fc80a
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutex_wrong_owner.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unlocked a default mutex that was not locked by the current thread
+  --> $DIR/libc_pthread_mutex_wrong_owner.rs:LL:CC
+   |
+LL | ...t_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0);
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked a default mutex that was not locked by the current thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/libc_pthread_mutex_wrong_owner.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutexattr_double_destroy.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutexattr_double_destroy.rs
new file mode 100644
index 000000000000..474a277516d9
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutexattr_double_destroy.rs
@@ -0,0 +1,17 @@
+//@ignore-target-windows: No libc on Windows
+
+/// Test that destroying a pthread_mutexattr twice fails, even without a check for number validity
+
+fn main() {
+    unsafe {
+        use core::mem::MaybeUninit;
+        let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
+
+        libc::pthread_mutexattr_init(attr.as_mut_ptr());
+
+        libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
+
+        libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
+        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutexattr_double_destroy.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutexattr_double_destroy.stderr
new file mode 100644
index 000000000000..82949047d2aa
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_mutexattr_double_destroy.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/libc_pthread_mutexattr_double_destroy.rs:LL:CC
+   |
+LL |         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_mutexattr_double_destroy.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_read_locked.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_read_locked.rs
new file mode 100644
index 000000000000..603580ff58ab
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_read_locked.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        assert_eq!(libc::pthread_rwlock_rdlock(rw.get()), 0);
+        libc::pthread_rwlock_destroy(rw.get()); //~ ERROR: destroyed a locked rwlock
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_read_locked.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_read_locked.stderr
new file mode 100644
index 000000000000..be73e7f1e2ad
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_read_locked.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: destroyed a locked rwlock
+  --> $DIR/libc_pthread_rwlock_destroy_read_locked.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_destroy(rw.get());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ destroyed a locked rwlock
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_rwlock_destroy_read_locked.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_write_locked.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_write_locked.rs
new file mode 100644
index 000000000000..ae44f22d146c
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_write_locked.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        assert_eq!(libc::pthread_rwlock_wrlock(rw.get()), 0);
+        libc::pthread_rwlock_destroy(rw.get()); //~ ERROR: destroyed a locked rwlock
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_write_locked.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_write_locked.stderr
new file mode 100644
index 000000000000..bc2713a5ffbf
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_destroy_write_locked.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: destroyed a locked rwlock
+  --> $DIR/libc_pthread_rwlock_destroy_write_locked.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_destroy(rw.get());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ destroyed a locked rwlock
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_rwlock_destroy_write_locked.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_double_destroy.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_double_destroy.rs
new file mode 100644
index 000000000000..800986f7506c
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_double_destroy.rs
@@ -0,0 +1,14 @@
+//@ignore-target-windows: No libc on Windows
+
+/// Test that destroying a pthread_rwlock twice fails, even without a check for number validity
+
+fn main() {
+    unsafe {
+        let mut lock = libc::PTHREAD_RWLOCK_INITIALIZER;
+
+        libc::pthread_rwlock_destroy(&mut lock);
+
+        libc::pthread_rwlock_destroy(&mut lock);
+        //~^ ERROR: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_double_destroy.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_double_destroy.stderr
new file mode 100644
index 000000000000..5004f84358da
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_double_destroy.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/libc_pthread_rwlock_double_destroy.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_destroy(&mut lock);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_rwlock_double_destroy.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs
new file mode 100644
index 000000000000..782c95b6d2e3
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        assert_eq!(libc::pthread_rwlock_rdlock(rw.get()), 0);
+        libc::pthread_rwlock_wrlock(rw.get()); //~ ERROR: deadlock
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.stderr
new file mode 100644
index 000000000000..075c8f0ef529
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_write_deadlock_single_thread.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_rwlock_read_write_deadlock_single_thread.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_wrlock(rw.get());
+   |                                             ^ the evaluated program deadlocked
+   |
+   = note: inside `main` at $DIR/libc_pthread_rwlock_read_write_deadlock_single_thread.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_wrong_owner.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_wrong_owner.rs
new file mode 100644
index 000000000000..1b498ad8fcdb
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_wrong_owner.rs
@@ -0,0 +1,28 @@
+//@ignore-target-windows: No libc on Windows
+
+use std::cell::UnsafeCell;
+use std::sync::Arc;
+use std::thread;
+
+struct RwLock(UnsafeCell<libc::pthread_rwlock_t>);
+
+unsafe impl Send for RwLock {}
+unsafe impl Sync for RwLock {}
+
+fn new_lock() -> Arc<RwLock> {
+    Arc::new(RwLock(UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER)))
+}
+
+fn main() {
+    unsafe {
+        let lock = new_lock();
+        assert_eq!(libc::pthread_rwlock_rdlock(lock.0.get() as *mut _), 0);
+
+        let lock_copy = lock.clone();
+        thread::spawn(move || {
+            assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _), 0); //~ ERROR: Undefined Behavior: unlocked an rwlock that was not locked by the active thread
+        })
+        .join()
+        .unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_wrong_owner.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_wrong_owner.stderr
new file mode 100644
index 000000000000..7dfa27b43d07
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_read_wrong_owner.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unlocked an rwlock that was not locked by the active thread
+  --> $DIR/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC
+   |
+LL | ...   assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _), 0);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked an rwlock that was not locked by the active thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_unlock_unlocked.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_unlock_unlocked.rs
new file mode 100644
index 000000000000..05f7e7a06c57
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_unlock_unlocked.rs
@@ -0,0 +1,8 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        libc::pthread_rwlock_unlock(rw.get()); //~ ERROR: was not locked
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_unlock_unlocked.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_unlock_unlocked.stderr
new file mode 100644
index 000000000000..1c25ac2c048f
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_unlock_unlocked.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unlocked an rwlock that was not locked by the active thread
+  --> $DIR/libc_pthread_rwlock_unlock_unlocked.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_unlock(rw.get());
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked an rwlock that was not locked by the active thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/libc_pthread_rwlock_unlock_unlocked.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock.rs
new file mode 100644
index 000000000000..201844615e18
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock.rs
@@ -0,0 +1,28 @@
+//@ignore-target-windows: No libc on Windows
+
+use std::cell::UnsafeCell;
+use std::sync::Arc;
+use std::thread;
+
+struct RwLock(UnsafeCell<libc::pthread_rwlock_t>);
+
+unsafe impl Send for RwLock {}
+unsafe impl Sync for RwLock {}
+
+fn new_lock() -> Arc<RwLock> {
+    Arc::new(RwLock(UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER)))
+}
+
+fn main() {
+    unsafe {
+        let lock = new_lock();
+        assert_eq!(libc::pthread_rwlock_rdlock(lock.0.get() as *mut _), 0);
+
+        let lock_copy = lock.clone();
+        thread::spawn(move || {
+            assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mut _), 0); //~ ERROR: deadlock
+        })
+        .join()
+        .unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock.stderr
new file mode 100644
index 000000000000..333fb1afb91b
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC
+   |
+LL |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mut _), 0);
+   |                                                                               ^ the evaluated program deadlocked
+   |
+   = note: inside closure at $DIR/libc_pthread_rwlock_write_read_deadlock.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs
new file mode 100644
index 000000000000..538f14ef89f2
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        assert_eq!(libc::pthread_rwlock_wrlock(rw.get()), 0);
+        libc::pthread_rwlock_rdlock(rw.get()); //~ ERROR: deadlock
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.stderr
new file mode 100644
index 000000000000..caab19a782f9
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_read_deadlock_single_thread.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_rwlock_write_read_deadlock_single_thread.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_rdlock(rw.get());
+   |                                             ^ the evaluated program deadlocked
+   |
+   = note: inside `main` at $DIR/libc_pthread_rwlock_write_read_deadlock_single_thread.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock.rs
new file mode 100644
index 000000000000..b1d7e0492e5a
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock.rs
@@ -0,0 +1,28 @@
+//@ignore-target-windows: No libc on Windows
+
+use std::cell::UnsafeCell;
+use std::sync::Arc;
+use std::thread;
+
+struct RwLock(UnsafeCell<libc::pthread_rwlock_t>);
+
+unsafe impl Send for RwLock {}
+unsafe impl Sync for RwLock {}
+
+fn new_lock() -> Arc<RwLock> {
+    Arc::new(RwLock(UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER)))
+}
+
+fn main() {
+    unsafe {
+        let lock = new_lock();
+        assert_eq!(libc::pthread_rwlock_wrlock(lock.0.get() as *mut _), 0);
+
+        let lock_copy = lock.clone();
+        thread::spawn(move || {
+            assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mut _), 0); //~ ERROR: deadlock
+        })
+        .join()
+        .unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock.stderr
new file mode 100644
index 000000000000..93bede54fcf1
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC
+   |
+LL |             assert_eq!(libc::pthread_rwlock_wrlock(lock_copy.0.get() as *mut _), 0);
+   |                                                                               ^ the evaluated program deadlocked
+   |
+   = note: inside closure at $DIR/libc_pthread_rwlock_write_write_deadlock.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs
new file mode 100644
index 000000000000..2c963d36510e
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        assert_eq!(libc::pthread_rwlock_wrlock(rw.get()), 0);
+        libc::pthread_rwlock_wrlock(rw.get()); //~ ERROR: deadlock
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.stderr
new file mode 100644
index 000000000000..30f5f447c717
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_write_deadlock_single_thread.stderr
@@ -0,0 +1,12 @@
+error: deadlock: the evaluated program deadlocked
+  --> $DIR/libc_pthread_rwlock_write_write_deadlock_single_thread.rs:LL:CC
+   |
+LL |         libc::pthread_rwlock_wrlock(rw.get());
+   |                                             ^ the evaluated program deadlocked
+   |
+   = note: inside `main` at $DIR/libc_pthread_rwlock_write_write_deadlock_single_thread.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_wrong_owner.rs b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_wrong_owner.rs
new file mode 100644
index 000000000000..dd099474d8fe
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_wrong_owner.rs
@@ -0,0 +1,28 @@
+//@ignore-target-windows: No libc on Windows
+
+use std::cell::UnsafeCell;
+use std::sync::Arc;
+use std::thread;
+
+struct RwLock(UnsafeCell<libc::pthread_rwlock_t>);
+
+unsafe impl Send for RwLock {}
+unsafe impl Sync for RwLock {}
+
+fn new_lock() -> Arc<RwLock> {
+    Arc::new(RwLock(UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER)))
+}
+
+fn main() {
+    unsafe {
+        let lock = new_lock();
+        assert_eq!(libc::pthread_rwlock_wrlock(lock.0.get() as *mut _), 0);
+
+        let lock_copy = lock.clone();
+        thread::spawn(move || {
+            assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _), 0); //~ ERROR: Undefined Behavior: unlocked an rwlock that was not locked by the active thread
+        })
+        .join()
+        .unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_wrong_owner.stderr b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_wrong_owner.stderr
new file mode 100644
index 000000000000..5bf402c775ae
--- /dev/null
+++ b/src/tools/miri/tests/fail/shims/sync/libc_pthread_rwlock_write_wrong_owner.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: unlocked an rwlock that was not locked by the active thread
+  --> $DIR/libc_pthread_rwlock_write_wrong_owner.rs:LL:CC
+   |
+LL | ...   assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _), 0);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked an rwlock that was not locked by the active thread
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/libc_pthread_rwlock_write_wrong_owner.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/should-pass/cpp20_rwc_syncs.rs b/src/tools/miri/tests/fail/should-pass/cpp20_rwc_syncs.rs
new file mode 100644
index 000000000000..545875a582a4
--- /dev/null
+++ b/src/tools/miri/tests/fail/should-pass/cpp20_rwc_syncs.rs
@@ -0,0 +1,87 @@
+//@compile-flags: -Zmiri-ignore-leaks
+
+// https://plv.mpi-sws.org/scfix/paper.pdf
+// 2.2 Second Problem: SC Fences are Too Weak
+// This test should pass under the C++20 model Rust is using.
+// Unfortunately, Miri's weak memory emulation only follows the C++11 model
+// as we don't know how to correctly emulate C++20's revised SC semantics,
+// so we have to stick to C++11 emulation from existing research.
+
+use std::sync::atomic::Ordering::*;
+use std::sync::atomic::{fence, AtomicUsize};
+use std::thread::spawn;
+
+// Spins until it reads the given value
+fn reads_value(loc: &AtomicUsize, val: usize) -> usize {
+    while loc.load(Relaxed) != val {
+        std::hint::spin_loop();
+    }
+    val
+}
+
+// We can't create static items because we need to run each test
+// multiple tests
+fn static_atomic(val: usize) -> &'static AtomicUsize {
+    let ret = Box::leak(Box::new(AtomicUsize::new(val)));
+    // A workaround to put the initialization value in the store buffer.
+    // See https://github.com/rust-lang/miri/issues/2164
+    ret.load(Relaxed);
+    ret
+}
+
+fn test_cpp20_rwc_syncs() {
+    /*
+    int main() {
+        atomic_int x = 0;
+        atomic_int y = 0;
+
+        {{{ x.store(1,mo_relaxed);
+        ||| { r1=x.load(mo_relaxed).readsvalue(1);
+              fence(mo_seq_cst);
+              r2=y.load(mo_relaxed); }
+        ||| { y.store(1,mo_relaxed);
+              fence(mo_seq_cst);
+              r3=x.load(mo_relaxed); }
+        }}}
+        return 0;
+    }
+    */
+    let x = static_atomic(0);
+    let y = static_atomic(0);
+
+    let j1 = spawn(move || {
+        x.store(1, Relaxed);
+    });
+
+    let j2 = spawn(move || {
+        reads_value(&x, 1);
+        fence(SeqCst);
+        y.load(Relaxed)
+    });
+
+    let j3 = spawn(move || {
+        y.store(1, Relaxed);
+        fence(SeqCst);
+        x.load(Relaxed)
+    });
+
+    j1.join().unwrap();
+    let b = j2.join().unwrap();
+    let c = j3.join().unwrap();
+
+    // We cannot write assert_ne!() since ui_test's fail
+    // tests expect exit status 1, whereas panics produce 101.
+    // Our ui_test does not yet support overriding failure status codes.
+    if (b, c) == (0, 0) {
+        // This *should* be unreachable, but Miri will reach it.
+        unsafe {
+            std::hint::unreachable_unchecked(); //~ERROR: unreachable
+        }
+    }
+}
+
+pub fn main() {
+    for _ in 0..500 {
+        test_cpp20_rwc_syncs();
+    }
+}
diff --git a/src/tools/miri/tests/fail/should-pass/cpp20_rwc_syncs.stderr b/src/tools/miri/tests/fail/should-pass/cpp20_rwc_syncs.stderr
new file mode 100644
index 000000000000..8a24b085a99f
--- /dev/null
+++ b/src/tools/miri/tests/fail/should-pass/cpp20_rwc_syncs.stderr
@@ -0,0 +1,20 @@
+error: Undefined Behavior: entering unreachable code
+  --> $DIR/cpp20_rwc_syncs.rs:LL:CC
+   |
+LL |             std::hint::unreachable_unchecked();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ entering unreachable code
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `test_cpp20_rwc_syncs` at $DIR/cpp20_rwc_syncs.rs:LL:CC
+note: inside `main` at $DIR/cpp20_rwc_syncs.rs:LL:CC
+  --> $DIR/cpp20_rwc_syncs.rs:LL:CC
+   |
+LL |         test_cpp20_rwc_syncs();
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/alias_through_mutation.rs b/src/tools/miri/tests/fail/stacked_borrows/alias_through_mutation.rs
new file mode 100644
index 000000000000..73095bb2fc94
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/alias_through_mutation.rs
@@ -0,0 +1,15 @@
+// This makes a ref that was passed to us via &mut alias with things it should not alias with
+fn retarget(x: &mut &u32, target: &mut u32) {
+    unsafe {
+        *x = &mut *(target as *mut _);
+    }
+}
+
+fn main() {
+    let target = &mut 42;
+    let mut target_alias = &42; // initial dummy value
+    retarget(&mut target_alias, target);
+    // now `target_alias` points to the same thing as `target`
+    *target = 13;
+    let _val = *target_alias; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/alias_through_mutation.stderr b/src/tools/miri/tests/fail/stacked_borrows/alias_through_mutation.stderr
new file mode 100644
index 000000000000..461275c3fa34
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/alias_through_mutation.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/alias_through_mutation.rs:LL:CC
+   |
+LL |     let _val = *target_alias;
+   |                ^^^^^^^^^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/alias_through_mutation.rs:LL:CC
+   |
+LL |         *x = &mut *(target as *mut _);
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/alias_through_mutation.rs:LL:CC
+   |
+LL |     *target = 13;
+   |     ^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/alias_through_mutation.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut1.rs b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut1.rs
new file mode 100644
index 000000000000..14a27d8e9dd6
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut1.rs
@@ -0,0 +1,14 @@
+use std::mem;
+
+pub fn safe(_x: &mut i32, _y: &mut i32) {} //~ ERROR: protect
+
+fn main() {
+    let mut x = 0;
+    let xraw: *mut i32 = unsafe { mem::transmute(&mut x) };
+    // We need to apply some tricky to be able to call `safe` with two mutable references
+    // with the same tag: We transmute both the fn ptr (to take raw ptrs) and the argument
+    // (to be raw, but still have the unique tag).
+    let safe_raw: fn(x: *mut i32, y: *mut i32) =
+        unsafe { mem::transmute::<fn(&mut i32, &mut i32), _>(safe) };
+    safe_raw(xraw, xraw);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut1.stderr b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut1.stderr
new file mode 100644
index 000000000000..5d4679b13ad1
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut1.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/aliasing_mut1.rs:LL:CC
+   |
+LL | pub fn safe(_x: &mut i32, _y: &mut i32) {}
+   |                           ^^ not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/aliasing_mut1.rs:LL:CC
+   |
+LL |     let xraw: *mut i32 = unsafe { mem::transmute(&mut x) };
+   |                                                  ^^^^^^
+help: <TAG> is this argument
+  --> $DIR/aliasing_mut1.rs:LL:CC
+   |
+LL | pub fn safe(_x: &mut i32, _y: &mut i32) {}
+   |             ^^
+   = note: BACKTRACE:
+   = note: inside `safe` at $DIR/aliasing_mut1.rs:LL:CC
+note: inside `main` at $DIR/aliasing_mut1.rs:LL:CC
+  --> $DIR/aliasing_mut1.rs:LL:CC
+   |
+LL |     safe_raw(xraw, xraw);
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut2.rs b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut2.rs
new file mode 100644
index 000000000000..84d901f83bbc
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut2.rs
@@ -0,0 +1,14 @@
+use std::mem;
+
+pub fn safe(_x: &i32, _y: &mut i32) {} //~ ERROR: protect
+
+fn main() {
+    let mut x = 0;
+    let xref = &mut x;
+    let xraw: *mut i32 = unsafe { mem::transmute_copy(&xref) };
+    let xshr = &*xref;
+    // transmute fn ptr around so that we can avoid retagging
+    let safe_raw: fn(x: *const i32, y: *mut i32) =
+        unsafe { mem::transmute::<fn(&i32, &mut i32), _>(safe) };
+    safe_raw(xshr, xraw);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut2.stderr b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut2.stderr
new file mode 100644
index 000000000000..c8408c150e77
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut2.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/aliasing_mut2.rs:LL:CC
+   |
+LL | pub fn safe(_x: &i32, _y: &mut i32) {}
+   |                       ^^ not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/aliasing_mut2.rs:LL:CC
+   |
+LL |     let xref = &mut x;
+   |                ^^^^^^
+help: <TAG> is this argument
+  --> $DIR/aliasing_mut2.rs:LL:CC
+   |
+LL | pub fn safe(_x: &i32, _y: &mut i32) {}
+   |             ^^
+   = note: BACKTRACE:
+   = note: inside `safe` at $DIR/aliasing_mut2.rs:LL:CC
+note: inside `main` at $DIR/aliasing_mut2.rs:LL:CC
+  --> $DIR/aliasing_mut2.rs:LL:CC
+   |
+LL |     safe_raw(xshr, xraw);
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut3.rs b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut3.rs
new file mode 100644
index 000000000000..f1ba06b6e4f7
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut3.rs
@@ -0,0 +1,14 @@
+use std::mem;
+
+pub fn safe(_x: &mut i32, _y: &i32) {} //~ ERROR: borrow stack
+
+fn main() {
+    let mut x = 0;
+    let xref = &mut x;
+    let xraw: *mut i32 = unsafe { mem::transmute_copy(&xref) };
+    let xshr = &*xref;
+    // transmute fn ptr around so that we can avoid retagging
+    let safe_raw: fn(x: *mut i32, y: *const i32) =
+        unsafe { mem::transmute::<fn(&mut i32, &i32), _>(safe) };
+    safe_raw(xraw, xshr);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut3.stderr b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut3.stderr
new file mode 100644
index 000000000000..c2ea90f242a2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut3.stderr
@@ -0,0 +1,33 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/aliasing_mut3.rs:LL:CC
+   |
+LL | pub fn safe(_x: &mut i32, _y: &i32) {}
+   |                           ^^
+   |                           |
+   |                           trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                           this error occurs as part of FnEntry retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/aliasing_mut3.rs:LL:CC
+   |
+LL |     safe_raw(xraw, xshr);
+   |                    ^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique FnEntry retag
+  --> $DIR/aliasing_mut3.rs:LL:CC
+   |
+LL |     safe_raw(xraw, xshr);
+   |     ^^^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `safe` at $DIR/aliasing_mut3.rs:LL:CC
+note: inside `main` at $DIR/aliasing_mut3.rs:LL:CC
+  --> $DIR/aliasing_mut3.rs:LL:CC
+   |
+LL |     safe_raw(xraw, xshr);
+   |     ^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut4.rs b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut4.rs
new file mode 100644
index 000000000000..52081b56223d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut4.rs
@@ -0,0 +1,16 @@
+use std::cell::Cell;
+use std::mem;
+
+// Make sure &mut UnsafeCell also is exclusive
+pub fn safe(_x: &i32, _y: &mut Cell<i32>) {} //~ ERROR: protect
+
+fn main() {
+    let mut x = 0;
+    let xref = &mut x;
+    let xraw: *mut i32 = unsafe { mem::transmute_copy(&xref) };
+    let xshr = &*xref;
+    // transmute fn ptr around so that we can avoid retagging
+    let safe_raw: fn(x: *const i32, y: *mut Cell<i32>) =
+        unsafe { mem::transmute::<fn(&i32, &mut Cell<i32>), _>(safe) };
+    safe_raw(xshr, xraw as *mut _);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut4.stderr b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut4.stderr
new file mode 100644
index 000000000000..c53fe70f6dd3
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/aliasing_mut4.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/aliasing_mut4.rs:LL:CC
+   |
+LL | pub fn safe(_x: &i32, _y: &mut Cell<i32>) {}
+   |                       ^^ not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/aliasing_mut4.rs:LL:CC
+   |
+LL |     let xref = &mut x;
+   |                ^^^^^^
+help: <TAG> is this argument
+  --> $DIR/aliasing_mut4.rs:LL:CC
+   |
+LL | pub fn safe(_x: &i32, _y: &mut Cell<i32>) {}
+   |             ^^
+   = note: BACKTRACE:
+   = note: inside `safe` at $DIR/aliasing_mut4.rs:LL:CC
+note: inside `main` at $DIR/aliasing_mut4.rs:LL:CC
+  --> $DIR/aliasing_mut4.rs:LL:CC
+   |
+LL |     safe_raw(xshr, xraw as *mut _);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/box_exclusive_violation1.rs b/src/tools/miri/tests/fail/stacked_borrows/box_exclusive_violation1.rs
new file mode 100644
index 000000000000..87a6b7bbd67e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/box_exclusive_violation1.rs
@@ -0,0 +1,33 @@
+fn demo_box_advanced_unique(mut our: Box<i32>) -> i32 {
+    unknown_code_1(&*our);
+
+    // This "re-asserts" uniqueness of the reference: After writing, we know
+    // our tag is at the top of the stack.
+    *our = 5;
+
+    unknown_code_2();
+
+    // We know this will return 5
+    *our
+}
+
+// Now comes the evil context
+use std::ptr;
+
+static mut LEAK: *mut i32 = ptr::null_mut();
+
+fn unknown_code_1(x: &i32) {
+    unsafe {
+        LEAK = x as *const _ as *mut _;
+    }
+}
+
+fn unknown_code_2() {
+    unsafe {
+        *LEAK = 7; //~ ERROR: /write access .* tag does not exist in the borrow stack/
+    }
+}
+
+fn main() {
+    demo_box_advanced_unique(Box::new(0));
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/box_exclusive_violation1.stderr b/src/tools/miri/tests/fail/stacked_borrows/box_exclusive_violation1.stderr
new file mode 100644
index 000000000000..d82b8342f123
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/box_exclusive_violation1.stderr
@@ -0,0 +1,38 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/box_exclusive_violation1.rs:LL:CC
+   |
+LL |         *LEAK = 7;
+   |         ^^^^^^^^^
+   |         |
+   |         attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |         this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/box_exclusive_violation1.rs:LL:CC
+   |
+LL |         LEAK = x as *const _ as *mut _;
+   |                ^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/box_exclusive_violation1.rs:LL:CC
+   |
+LL |     *our = 5;
+   |     ^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `unknown_code_2` at $DIR/box_exclusive_violation1.rs:LL:CC
+note: inside `demo_box_advanced_unique` at $DIR/box_exclusive_violation1.rs:LL:CC
+  --> $DIR/box_exclusive_violation1.rs:LL:CC
+   |
+LL |     unknown_code_2();
+   |     ^^^^^^^^^^^^^^^^
+note: inside `main` at $DIR/box_exclusive_violation1.rs:LL:CC
+  --> $DIR/box_exclusive_violation1.rs:LL:CC
+   |
+LL |     demo_box_advanced_unique(Box::new(0));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/buggy_as_mut_slice.rs b/src/tools/miri/tests/fail/stacked_borrows/buggy_as_mut_slice.rs
new file mode 100644
index 000000000000..8615a9a58ad9
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/buggy_as_mut_slice.rs
@@ -0,0 +1,15 @@
+mod safe {
+    use std::slice::from_raw_parts_mut;
+
+    pub fn as_mut_slice<T>(self_: &Vec<T>) -> &mut [T] {
+        unsafe { from_raw_parts_mut(self_.as_ptr() as *mut T, self_.len()) }
+    }
+}
+
+fn main() {
+    let v = vec![0, 1, 2];
+    let v1 = safe::as_mut_slice(&v);
+    let _v2 = safe::as_mut_slice(&v);
+    v1[1] = 5;
+    //~^ ERROR: /write access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/buggy_as_mut_slice.stderr b/src/tools/miri/tests/fail/stacked_borrows/buggy_as_mut_slice.stderr
new file mode 100644
index 000000000000..6aa14361287e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/buggy_as_mut_slice.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/buggy_as_mut_slice.rs:LL:CC
+   |
+LL |     v1[1] = 5;
+   |     ^^^^^^^^^
+   |     |
+   |     attempting a write access using <TAG> at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |     this error occurs as part of an access at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0xc]
+  --> $DIR/buggy_as_mut_slice.rs:LL:CC
+   |
+LL |     let v1 = safe::as_mut_slice(&v);
+   |              ^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0xc] by a Unique retag
+  --> $DIR/buggy_as_mut_slice.rs:LL:CC
+   |
+LL |         unsafe { from_raw_parts_mut(self_.as_ptr() as *mut T, self_.len()) }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/buggy_as_mut_slice.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/buggy_split_at_mut.rs b/src/tools/miri/tests/fail/stacked_borrows/buggy_split_at_mut.rs
new file mode 100644
index 000000000000..8a1ea86d6338
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/buggy_split_at_mut.rs
@@ -0,0 +1,25 @@
+mod safe {
+    use std::slice::from_raw_parts_mut;
+
+    pub fn split_at_mut<T>(self_: &mut [T], mid: usize) -> (&mut [T], &mut [T]) {
+        let len = self_.len();
+        let ptr = self_.as_mut_ptr();
+
+        unsafe {
+            assert!(mid <= len);
+
+            (
+                from_raw_parts_mut(ptr, len - mid), // BUG: should be "mid" instead of "len - mid"
+                from_raw_parts_mut(ptr.offset(mid as isize), len - mid),
+            )
+        }
+    }
+}
+
+fn main() {
+    let mut array = [1, 2, 3, 4];
+    let (a, b) = safe::split_at_mut(&mut array, 0);
+    //~^ ERROR: /retag .* tag does not exist in the borrow stack/
+    a[1] = 5;
+    b[1] = 6;
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/buggy_split_at_mut.stderr b/src/tools/miri/tests/fail/stacked_borrows/buggy_split_at_mut.stderr
new file mode 100644
index 000000000000..cdeccc0855a9
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/buggy_split_at_mut.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for Unique permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/buggy_split_at_mut.rs:LL:CC
+   |
+LL |     let (a, b) = safe::split_at_mut(&mut array, 0);
+   |          ^
+   |          |
+   |          trying to retag from <TAG> for Unique permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |          this error occurs as part of retag at ALLOC[0x0..0x10]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x10]
+  --> $DIR/buggy_split_at_mut.rs:LL:CC
+   |
+LL |                 from_raw_parts_mut(ptr, len - mid), // BUG: should be "mid" instead of "len - mid"
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x10] by a Unique retag
+  --> $DIR/buggy_split_at_mut.rs:LL:CC
+   |
+LL |                 from_raw_parts_mut(ptr.offset(mid as isize), len - mid),
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/buggy_split_at_mut.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.rs b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.rs
new file mode 100644
index 000000000000..9b710424c55c
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.rs
@@ -0,0 +1,13 @@
+//@error-pattern: /deallocating while item \[Unique for .*\] is protected/
+
+fn inner(x: &mut i32, f: fn(&mut i32)) {
+    // `f` may mutate, but it may not deallocate!
+    f(x)
+}
+
+fn main() {
+    inner(Box::leak(Box::new(0)), |x| {
+        let raw = x as *mut _;
+        drop(unsafe { Box::from_raw(raw) });
+    });
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr
new file mode 100644
index 000000000000..a5db4a00c69e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr
@@ -0,0 +1,38 @@
+error: Undefined Behavior: deallocating while item [Unique for <TAG>] is protected by call ID
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating while item [Unique for <TAG>] is protected by call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `<std::alloc::Global as std::alloc::Allocator>::deallocate` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `alloc::alloc::box_free::<i32, std::alloc::Global>` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
+note: inside closure at $DIR/deallocate_against_protector1.rs:LL:CC
+  --> $DIR/deallocate_against_protector1.rs:LL:CC
+   |
+LL |         drop(unsafe { Box::from_raw(raw) });
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `<[closure@$DIR/deallocate_against_protector1.rs:LL:CC] as std::ops::FnOnce<(&mut i32,)>>::call_once - shim` at RUSTLIB/core/src/ops/function.rs:LL:CC
+note: inside `inner` at $DIR/deallocate_against_protector1.rs:LL:CC
+  --> $DIR/deallocate_against_protector1.rs:LL:CC
+   |
+LL |     f(x)
+   |     ^^^^
+note: inside `main` at $DIR/deallocate_against_protector1.rs:LL:CC
+  --> $DIR/deallocate_against_protector1.rs:LL:CC
+   |
+LL | /     inner(Box::leak(Box::new(0)), |x| {
+LL | |         let raw = x as *mut _;
+LL | |         drop(unsafe { Box::from_raw(raw) });
+LL | |     });
+   | |______^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector2.rs b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector2.rs
new file mode 100644
index 000000000000..36e133e38365
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector2.rs
@@ -0,0 +1,16 @@
+//@error-pattern: /deallocating while item \[SharedReadWrite for .*\] is protected/
+use std::marker::PhantomPinned;
+
+pub struct NotUnpin(i32, PhantomPinned);
+
+fn inner(x: &mut NotUnpin, f: fn(&mut NotUnpin)) {
+    // `f` may mutate, but it may not deallocate!
+    f(x)
+}
+
+fn main() {
+    inner(Box::leak(Box::new(NotUnpin(0, PhantomPinned))), |x| {
+        let raw = x as *mut _;
+        drop(unsafe { Box::from_raw(raw) });
+    });
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector2.stderr b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector2.stderr
new file mode 100644
index 000000000000..99c6ee6eb074
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector2.stderr
@@ -0,0 +1,38 @@
+error: Undefined Behavior: deallocating while item [SharedReadWrite for <TAG>] is protected by call ID
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating while item [SharedReadWrite for <TAG>] is protected by call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+   = note: BACKTRACE:
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `<std::alloc::Global as std::alloc::Allocator>::deallocate` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `alloc::alloc::box_free::<NotUnpin, std::alloc::Global>` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `std::ptr::drop_in_place::<std::boxed::Box<NotUnpin>> - shim(Some(std::boxed::Box<NotUnpin>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: inside `std::mem::drop::<std::boxed::Box<NotUnpin>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
+note: inside closure at $DIR/deallocate_against_protector2.rs:LL:CC
+  --> $DIR/deallocate_against_protector2.rs:LL:CC
+   |
+LL |         drop(unsafe { Box::from_raw(raw) });
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `<[closure@$DIR/deallocate_against_protector2.rs:LL:CC] as std::ops::FnOnce<(&mut NotUnpin,)>>::call_once - shim` at RUSTLIB/core/src/ops/function.rs:LL:CC
+note: inside `inner` at $DIR/deallocate_against_protector2.rs:LL:CC
+  --> $DIR/deallocate_against_protector2.rs:LL:CC
+   |
+LL |     f(x)
+   |     ^^^^
+note: inside `main` at $DIR/deallocate_against_protector2.rs:LL:CC
+  --> $DIR/deallocate_against_protector2.rs:LL:CC
+   |
+LL | /     inner(Box::leak(Box::new(NotUnpin(0, PhantomPinned))), |x| {
+LL | |         let raw = x as *mut _;
+LL | |         drop(unsafe { Box::from_raw(raw) });
+LL | |     });
+   | |______^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/disable_mut_does_not_merge_srw.rs b/src/tools/miri/tests/fail/stacked_borrows/disable_mut_does_not_merge_srw.rs
new file mode 100644
index 000000000000..fed5cd26f4d6
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/disable_mut_does_not_merge_srw.rs
@@ -0,0 +1,22 @@
+// This tests demonstrates the effect of 'Disabling' mutable references on reads, rather than
+// removing them from the stack -- the latter would 'merge' neighboring SRW groups which we would
+// like to avoid.
+fn main() {
+    unsafe {
+        let mut mem = 0;
+        let base = &mut mem as *mut i32; // the base pointer we build the rest of the stack on
+        let raw = {
+            let mutref = &mut *base;
+            mutref as *mut i32
+        };
+        // In the stack, we now have [base, mutref, raw].
+        // We do this in a weird way where `mutref` is out of scope here, just in case
+        // Miri decides to get smart and argue that items for tags that are no longer
+        // used by any pointer stored anywhere in the machine can be removed.
+        let _val = *base;
+        // now mutref is disabled
+        *base = 1;
+        // this should pop raw from the stack, since it is in a different SRW group
+        let _val = *raw; //~ERROR: that tag does not exist in the borrow stack
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/disable_mut_does_not_merge_srw.stderr b/src/tools/miri/tests/fail/stacked_borrows/disable_mut_does_not_merge_srw.stderr
new file mode 100644
index 000000000000..e05f44fac9d2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/disable_mut_does_not_merge_srw.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/disable_mut_does_not_merge_srw.rs:LL:CC
+   |
+LL |         let _val = *raw;
+   |                    ^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/disable_mut_does_not_merge_srw.rs:LL:CC
+   |
+LL |             mutref as *mut i32
+   |             ^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/disable_mut_does_not_merge_srw.rs:LL:CC
+   |
+LL |         *base = 1;
+   |         ^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/disable_mut_does_not_merge_srw.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/exposed_only_ro.rs b/src/tools/miri/tests/fail/stacked_borrows/exposed_only_ro.rs
new file mode 100644
index 000000000000..0b4fb0ccd33b
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/exposed_only_ro.rs
@@ -0,0 +1,12 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(strict_provenance)]
+
+// If we have only exposed read-only pointers, doing a write through a wildcard ptr should fail.
+
+fn main() {
+    let mut x = 0;
+    let _fool = &mut x as *mut i32; // this would have fooled the old untagged pointer logic
+    let addr = (&x as *const i32).expose_addr();
+    let ptr = std::ptr::from_exposed_addr_mut::<i32>(addr);
+    unsafe { *ptr = 0 }; //~ ERROR: /write access using <wildcard> .* no exposed tags have suitable permission in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/exposed_only_ro.stderr b/src/tools/miri/tests/fail/stacked_borrows/exposed_only_ro.stderr
new file mode 100644
index 000000000000..cb5e7bffde48
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/exposed_only_ro.stderr
@@ -0,0 +1,18 @@
+error: Undefined Behavior: attempting a write access using <wildcard> at ALLOC[0x0], but no exposed tags have suitable permission in the borrow stack for this location
+  --> $DIR/exposed_only_ro.rs:LL:CC
+   |
+LL |     unsafe { *ptr = 0 };
+   |              ^^^^^^^^
+   |              |
+   |              attempting a write access using <wildcard> at ALLOC[0x0], but no exposed tags have suitable permission in the borrow stack for this location
+   |              this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/exposed_only_ro.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/fnentry_invalidation.rs b/src/tools/miri/tests/fail/stacked_borrows/fnentry_invalidation.rs
new file mode 100644
index 000000000000..37214bebb828
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/fnentry_invalidation.rs
@@ -0,0 +1,20 @@
+// Test that spans displayed in diagnostics identify the function call, not the function
+// definition, as the location of invalidation due to FnEntry retag. Technically the FnEntry retag
+// occurs inside the function, but what the user wants to know is which call produced the
+// invalidation.
+fn main() {
+    let mut x = 0i32;
+    let z = &mut x as *mut i32;
+    x.do_bad();
+    unsafe {
+        let _oof = *z; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
+
+trait Bad {
+    fn do_bad(&mut self) {
+        // who knows
+    }
+}
+
+impl Bad for i32 {}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/fnentry_invalidation.stderr b/src/tools/miri/tests/fail/stacked_borrows/fnentry_invalidation.stderr
new file mode 100644
index 000000000000..653ceca85885
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/fnentry_invalidation.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/fnentry_invalidation.rs:LL:CC
+   |
+LL |         let _oof = *z;
+   |                    ^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/fnentry_invalidation.rs:LL:CC
+   |
+LL |     let z = &mut x as *mut i32;
+   |             ^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique FnEntry retag
+  --> $DIR/fnentry_invalidation.rs:LL:CC
+   |
+LL |     x.do_bad();
+   |     ^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/fnentry_invalidation.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read1.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read1.rs
new file mode 100644
index 000000000000..1dea282739ce
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read1.rs
@@ -0,0 +1,16 @@
+// A callee may not read the destination of our `&mut` without
+// us noticing.
+
+#[rustfmt::skip] // rustfmt bug: https://github.com/rust-lang/rustfmt/issues/5391
+fn main() {
+    let mut x = 15;
+    let xraw = &mut x as *mut _;
+    let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
+    callee(xraw);
+    let _val = *xref; // ...but any use of raw will invalidate our ref.
+    //~^ ERROR: /read access .* tag does not exist in the borrow stack/
+}
+
+fn callee(xraw: *mut i32) {
+    let _val = unsafe { *xraw };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read1.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read1.stderr
new file mode 100644
index 000000000000..95ff05d70c30
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read1.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read1.rs:LL:CC
+   |
+LL |     let _val = *xref; // ...but any use of raw will invalidate our ref.
+   |                ^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read1.rs:LL:CC
+   |
+LL |     let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
+   |                         ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/illegal_read1.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw };
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read2.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read2.rs
new file mode 100644
index 000000000000..b765b4d9ce99
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read2.rs
@@ -0,0 +1,19 @@
+// A callee may not read the destination of our `&mut` without
+// us noticing.
+
+#[rustfmt::skip] // rustfmt bug: https://github.com/rust-lang/rustfmt/issues/5391
+fn main() {
+    let mut x = 15;
+    let xraw = &mut x as *mut _;
+    let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
+    callee(xraw);
+    let _val = *xref; // ...but any use of raw will invalidate our ref.
+    //~^ ERROR: /read access .* tag does not exist in the borrow stack/
+}
+
+fn callee(xraw: *mut i32) {
+    // We are a bit sneaky: We first create a shared ref, exploiting the reborrowing rules,
+    // and then we read through that.
+    let shr = unsafe { &*xraw };
+    let _val = *shr;
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read2.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read2.stderr
new file mode 100644
index 000000000000..5cfdf77dee40
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read2.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read2.rs:LL:CC
+   |
+LL |     let _val = *xref; // ...but any use of raw will invalidate our ref.
+   |                ^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read2.rs:LL:CC
+   |
+LL |     let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
+   |                         ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a SharedReadOnly retag
+  --> $DIR/illegal_read2.rs:LL:CC
+   |
+LL |     let shr = unsafe { &*xraw };
+   |                        ^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read3.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read3.rs
new file mode 100644
index 000000000000..43ea0a0e84da
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read3.rs
@@ -0,0 +1,28 @@
+// A callee may not read the destination of our `&mut` without us noticing.
+// Thise code got carefully checked to not introduce any reborrows
+// that are not explicit in the source. Let's hope the compiler does not break this later!
+
+use std::mem;
+
+union HiddenRef {
+    // We avoid retagging at this type, and we only read, so shared vs mutable does not matter.
+    r: &'static i32,
+}
+
+fn main() {
+    let mut x: i32 = 15;
+    let xref1 = &mut x;
+    let xref1_sneaky: HiddenRef = unsafe { mem::transmute_copy(&xref1) };
+    // Derived from `xref1`, so using raw value is still ok, ...
+    let xref2 = &mut *xref1;
+    callee(xref1_sneaky);
+    // ... though any use of it will invalidate our ref.
+    let _val = *xref2;
+    //~^ ERROR: /read access .* tag does not exist in the borrow stack/
+}
+
+fn callee(xref1: HiddenRef) {
+    // Doing the deref and the transmute (through the union) in the same place expression
+    // should avoid retagging.
+    let _val = unsafe { *xref1.r };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read3.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read3.stderr
new file mode 100644
index 000000000000..dacf71fa3ee3
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read3.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read3.rs:LL:CC
+   |
+LL |     let _val = *xref2;
+   |                ^^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read3.rs:LL:CC
+   |
+LL |     let xref2 = &mut *xref1;
+   |                 ^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/illegal_read3.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xref1.r };
+   |                         ^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read4.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read4.rs
new file mode 100644
index 000000000000..a9ecb88d3520
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read4.rs
@@ -0,0 +1,9 @@
+// Using a raw invalidates derived `&mut` even for reading.
+fn main() {
+    let mut x = 2;
+    let xref1 = &mut x;
+    let xraw = xref1 as *mut _;
+    let xref2 = unsafe { &mut *xraw };
+    let _val = unsafe { *xraw }; // use the raw again, this invalidates xref2 *even* with the special read except for uniq refs
+    let _illegal = *xref2; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read4.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read4.stderr
new file mode 100644
index 000000000000..5ce0cba61791
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read4.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read4.rs:LL:CC
+   |
+LL |     let _illegal = *xref2;
+   |                    ^^^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read4.rs:LL:CC
+   |
+LL |     let xref2 = unsafe { &mut *xraw };
+   |                          ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/illegal_read4.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw }; // use the raw again, this invalidates xref2 *even* with the special read except for uniq refs
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read4.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read5.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read5.rs
new file mode 100644
index 000000000000..228c15f72e17
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read5.rs
@@ -0,0 +1,18 @@
+// We *can* have aliasing &RefCell<T> and &mut T, but we cannot read through the former.
+// Else we couldn't optimize based on the assumption that `xref` below is truly unique.
+//@normalize-stderr-test: "0x[0-9a-fA-F]+" -> "$$HEX"
+
+use std::cell::RefCell;
+use std::{mem, ptr};
+
+#[rustfmt::skip] // rustfmt bug: https://github.com/rust-lang/rustfmt/issues/5391
+fn main() {
+    let rc = RefCell::new(0);
+    let mut refmut = rc.borrow_mut();
+    let xref: &mut i32 = &mut *refmut;
+    let xshr = &rc; // creating this is ok
+    let _val = *xref; // we can even still use our mutable reference
+    mem::forget(unsafe { ptr::read(xshr) }); // but after reading through the shared ref
+    let _val = *xref; // the mutable one is dead and gone
+    //~^ ERROR: /read access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read5.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read5.stderr
new file mode 100644
index 000000000000..63532f87944e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read5.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[$HEX], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read5.rs:LL:CC
+   |
+LL |     let _val = *xref; // the mutable one is dead and gone
+   |                ^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[$HEX], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[$HEX..$HEX]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [$HEX..$HEX]
+  --> $DIR/illegal_read5.rs:LL:CC
+   |
+LL |     let xref: &mut i32 = &mut *refmut;
+   |                          ^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [$HEX..$HEX] by a read access
+  --> $DIR/illegal_read5.rs:LL:CC
+   |
+LL |     mem::forget(unsafe { ptr::read(xshr) }); // but after reading through the shared ref
+   |                          ^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read5.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read6.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read6.rs
new file mode 100644
index 000000000000..4af22580ab64
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read6.rs
@@ -0,0 +1,10 @@
+// Creating a shared reference does not leak the data to raw pointers.
+fn main() {
+    unsafe {
+        let x = &mut 0;
+        let raw = x as *mut _;
+        let x = &mut *x; // kill `raw`
+        let _y = &*x; // this should not activate `raw` again
+        let _val = *raw; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read6.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read6.stderr
new file mode 100644
index 000000000000..93a96ab601ea
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read6.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read6.rs:LL:CC
+   |
+LL |         let _val = *raw;
+   |                    ^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read6.rs:LL:CC
+   |
+LL |         let raw = x as *mut _;
+   |                   ^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique retag
+  --> $DIR/illegal_read6.rs:LL:CC
+   |
+LL |         let x = &mut *x; // kill `raw`
+   |                 ^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read6.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read7.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read7.rs
new file mode 100644
index 000000000000..1901e8e4e348
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read7.rs
@@ -0,0 +1,22 @@
+// Creating a shared reference does not leak the data to raw pointers,
+// not even when interior mutability is involved.
+
+use std::cell::Cell;
+use std::ptr;
+
+fn main() {
+    unsafe {
+        let x = &mut Cell::new(0);
+        let raw = x as *mut Cell<i32>;
+        let x = &mut *raw;
+        let _shr = &*x;
+        // The state here is interesting because the top of the stack is [Unique, SharedReadWrite],
+        // just like if we had done `x as *mut _`.
+        // If we said that reading from a lower item is fine if the top item is `SharedReadWrite`
+        // (one way to maybe preserve a stack discipline), then we could now read from `raw`
+        // without invalidating `x`.  That would be bad!  It would mean that creating `shr`
+        // leaked `x` to `raw`.
+        let _val = ptr::read(raw);
+        let _val = *x.get_mut(); //~ ERROR: /retag .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read7.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read7.stderr
new file mode 100644
index 000000000000..2e8ac207beaf
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read7.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read7.rs:LL:CC
+   |
+LL |         let _val = *x.get_mut();
+   |                     ^^^^^^^^^^^
+   |                     |
+   |                     trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                     this error occurs as part of two-phase retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read7.rs:LL:CC
+   |
+LL |         let x = &mut *raw;
+   |                 ^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/illegal_read7.rs:LL:CC
+   |
+LL |         let _val = ptr::read(raw);
+   |                    ^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read7.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read8.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read8.rs
new file mode 100644
index 000000000000..f0a1658a5a23
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read8.rs
@@ -0,0 +1,15 @@
+// Make sure that creating a raw ptr next to a shared ref works
+// but the shared ref still gets invalidated when the raw ptr is used for writing.
+
+fn main() {
+    unsafe {
+        use std::mem;
+        let x = &mut 0;
+        let y1: &i32 = mem::transmute(&*x); // launder lifetimes
+        let y2 = x as *mut _;
+        let _val = *y2;
+        let _val = *y1;
+        *y2 += 1;
+        let _fail = *y1; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read8.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read8.stderr
new file mode 100644
index 000000000000..c34fa2d8955d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read8.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read8.rs:LL:CC
+   |
+LL |         let _fail = *y1;
+   |                     ^^^
+   |                     |
+   |                     attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                     this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read8.rs:LL:CC
+   |
+LL |         let y1: &i32 = mem::transmute(&*x); // launder lifetimes
+   |                        ^^^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/illegal_read8.rs:LL:CC
+   |
+LL |         *y2 += 1;
+   |         ^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read8.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed1.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed1.rs
new file mode 100644
index 000000000000..76516b7d924b
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed1.rs
@@ -0,0 +1,17 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    unsafe {
+        let root = &mut 42;
+        let addr = root as *mut i32 as usize;
+        let exposed_ptr = addr as *mut i32;
+        // From the exposed ptr, we get a new unique ptr.
+        let root2 = &mut *exposed_ptr;
+        let _fool = root2 as *mut _; // this would have fooled the old untagged pointer logic
+        // Stack: Unknown(<N), Unique(N), SRW(N+1)
+        // And we test that it has uniqueness by doing a conflicting write.
+        *exposed_ptr = 0;
+        // Stack: Unknown(<N)
+        let _val = *root2; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed1.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed1.stderr
new file mode 100644
index 000000000000..43b4ec2ba652
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed1.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read_despite_exposed1.rs:LL:CC
+   |
+LL |         let _val = *root2;
+   |                    ^^^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read_despite_exposed1.rs:LL:CC
+   |
+LL |         let root2 = &mut *exposed_ptr;
+   |                     ^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/illegal_read_despite_exposed1.rs:LL:CC
+   |
+LL |         *exposed_ptr = 0;
+   |         ^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read_despite_exposed1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed2.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed2.rs
new file mode 100644
index 000000000000..97e0bf40c0dd
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed2.rs
@@ -0,0 +1,20 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    unsafe {
+        let root = &mut 42;
+        let addr = root as *mut i32 as usize;
+        let exposed_ptr = addr as *mut i32;
+        // From the exposed ptr, we get a new unique ptr.
+        let root2 = &mut *exposed_ptr;
+        // let _fool = root2 as *mut _; // this would fool us, since SRW(N+1) remains on the stack
+        // Stack: Unknown(<N), Unique(N)
+        // Stack if _fool existed: Unknown(<N), Unique(N), SRW(N+1)
+        // And we test that it has uniqueness by doing a conflicting read.
+        let _val = *exposed_ptr;
+        // Stack: Unknown(<N), Disabled(N)
+        // collapsed to Unknown(<N)
+        // Stack if _fool existed: Unknown(<N), Disabled(N), SRW(N+1); collapsed to Unknown(<N+2) which would not cause an ERROR
+        let _val = *root2; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed2.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed2.stderr
new file mode 100644
index 000000000000..832320fc202e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_read_despite_exposed2.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_read_despite_exposed2.rs:LL:CC
+   |
+LL |         let _val = *root2;
+   |                    ^^^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_read_despite_exposed2.rs:LL:CC
+   |
+LL |         let root2 = &mut *exposed_ptr;
+   |                     ^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/illegal_read_despite_exposed2.rs:LL:CC
+   |
+LL |         let _val = *exposed_ptr;
+   |                    ^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_read_despite_exposed2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write1.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write1.rs
new file mode 100644
index 000000000000..f28401938a92
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write1.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let target = Box::new(42); // has an implicit raw
+    let xref = &*target;
+    {
+        let x: *mut u32 = xref as *const _ as *mut _;
+        unsafe { *x = 42 }; //~ ERROR: /write access .* tag only grants SharedReadOnly permission/
+    }
+    let _x = *xref;
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write1.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write1.stderr
new file mode 100644
index 000000000000..3bf27f4815e9
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write1.stderr
@@ -0,0 +1,23 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag only grants SharedReadOnly permission for this location
+  --> $DIR/illegal_write1.rs:LL:CC
+   |
+LL |         unsafe { *x = 42 };
+   |                  ^^^^^^^
+   |                  |
+   |                  attempting a write access using <TAG> at ALLOC[0x0], but that tag only grants SharedReadOnly permission for this location
+   |                  this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write1.rs:LL:CC
+   |
+LL |         let x: *mut u32 = xref as *const _ as *mut _;
+   |                           ^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_write1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write2.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write2.rs
new file mode 100644
index 000000000000..70c51e671fe8
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write2.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let target = &mut 42;
+    let target2 = target as *mut _;
+    drop(&mut *target); // reborrow
+    // Now make sure our ref is still the only one.
+    unsafe { *target2 = 13 }; //~ ERROR: /write access .* tag does not exist in the borrow stack/
+    let _val = *target;
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write2.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write2.stderr
new file mode 100644
index 000000000000..a9fe8cb6ccc0
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write2.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_write2.rs:LL:CC
+   |
+LL |     unsafe { *target2 = 13 };
+   |              ^^^^^^^^^^^^^
+   |              |
+   |              attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |              this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write2.rs:LL:CC
+   |
+LL |     let target2 = target as *mut _;
+   |                   ^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique retag
+  --> $DIR/illegal_write2.rs:LL:CC
+   |
+LL |     drop(&mut *target); // reborrow
+   |          ^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_write2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write3.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write3.rs
new file mode 100644
index 000000000000..6f55b63cb5c6
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write3.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let target = 42;
+    // Make sure raw ptr with raw tag cannot mutate frozen location without breaking the shared ref.
+    let r#ref = &target; // freeze
+    let ptr = r#ref as *const _ as *mut _; // raw ptr, with raw tag
+    unsafe { *ptr = 42 }; //~ ERROR: /write access .* only grants SharedReadOnly permission/
+    let _val = *r#ref;
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write3.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write3.stderr
new file mode 100644
index 000000000000..d64f2ddd8767
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write3.stderr
@@ -0,0 +1,23 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag only grants SharedReadOnly permission for this location
+  --> $DIR/illegal_write3.rs:LL:CC
+   |
+LL |     unsafe { *ptr = 42 };
+   |              ^^^^^^^^^
+   |              |
+   |              attempting a write access using <TAG> at ALLOC[0x0], but that tag only grants SharedReadOnly permission for this location
+   |              this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write3.rs:LL:CC
+   |
+LL |     let ptr = r#ref as *const _ as *mut _; // raw ptr, with raw tag
+   |               ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_write3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write4.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write4.rs
new file mode 100644
index 000000000000..4c5d5a4f6657
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write4.rs
@@ -0,0 +1,13 @@
+use std::mem;
+
+fn main() {
+    let mut target = 42;
+    // Make sure we cannot use a raw-tagged `&mut` pointing to a frozen location.
+    // Even just creating it unfreezes.
+    let raw = &mut target as *mut _; // let this leak to raw
+    let reference = unsafe { &*raw }; // freeze
+    let _ptr = reference as *const _ as *mut i32; // raw ptr, with raw tag
+    let _mut_ref: &mut i32 = unsafe { mem::transmute(raw) }; // &mut, with raw tag
+    // Now we retag, making our ref top-of-stack -- and, in particular, unfreezing.
+    let _val = *reference; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write4.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write4.stderr
new file mode 100644
index 000000000000..e3b8621eb74f
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write4.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_write4.rs:LL:CC
+   |
+LL |     let _val = *reference;
+   |                ^^^^^^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write4.rs:LL:CC
+   |
+LL |     let reference = unsafe { &*raw }; // freeze
+   |                              ^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique retag
+  --> $DIR/illegal_write4.rs:LL:CC
+   |
+LL |     let _mut_ref: &mut i32 = unsafe { mem::transmute(raw) }; // &mut, with raw tag
+   |                                       ^^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_write4.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write5.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write5.rs
new file mode 100644
index 000000000000..1c655dc0a0fb
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write5.rs
@@ -0,0 +1,16 @@
+// A callee may not write to the destination of our `&mut` without us noticing.
+
+fn main() {
+    let mut x = 15;
+    let xraw = &mut x as *mut _;
+    // Derived from raw value, so using raw value is still ok ...
+    let xref = unsafe { &mut *xraw };
+    callee(xraw);
+    // ... though any use of raw value will invalidate our ref.
+    let _val = *xref;
+    //~^ ERROR: /read access .* tag does not exist in the borrow stack/
+}
+
+fn callee(xraw: *mut i32) {
+    unsafe { *xraw = 15 };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write5.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write5.stderr
new file mode 100644
index 000000000000..bbeb81258bde
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write5.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_write5.rs:LL:CC
+   |
+LL |     let _val = *xref;
+   |                ^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write5.rs:LL:CC
+   |
+LL |     let xref = unsafe { &mut *xraw };
+   |                         ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/illegal_write5.rs:LL:CC
+   |
+LL |     unsafe { *xraw = 15 };
+   |              ^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_write5.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write6.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write6.rs
new file mode 100644
index 000000000000..448f1493367a
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write6.rs
@@ -0,0 +1,12 @@
+fn main() {
+    let x = &mut 0u32;
+    let p = x as *mut u32;
+    foo(x, p);
+}
+
+fn foo(a: &mut u32, y: *mut u32) -> u32 {
+    *a = 1;
+    let _b = &*a;
+    unsafe { *y = 2 }; //~ ERROR: /not granting access .* because that would remove .* which is protected/
+    return *a;
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write6.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write6.stderr
new file mode 100644
index 000000000000..331faa89f860
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write6.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/illegal_write6.rs:LL:CC
+   |
+LL |     unsafe { *y = 2 };
+   |              ^^^^^^ not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write6.rs:LL:CC
+   |
+LL |     let p = x as *mut u32;
+   |             ^
+help: <TAG> is this argument
+  --> $DIR/illegal_write6.rs:LL:CC
+   |
+LL | fn foo(a: &mut u32, y: *mut u32) -> u32 {
+   |        ^
+   = note: BACKTRACE:
+   = note: inside `foo` at $DIR/illegal_write6.rs:LL:CC
+note: inside `main` at $DIR/illegal_write6.rs:LL:CC
+  --> $DIR/illegal_write6.rs:LL:CC
+   |
+LL |     foo(x, p);
+   |     ^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write_despite_exposed1.rs b/src/tools/miri/tests/fail/stacked_borrows/illegal_write_despite_exposed1.rs
new file mode 100644
index 000000000000..0e34c5c98fc1
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write_despite_exposed1.rs
@@ -0,0 +1,17 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    unsafe {
+        let root = &mut 42;
+        let addr = root as *mut i32 as usize;
+        let exposed_ptr = addr as *mut i32;
+        // From the exposed ptr, we get a new SRO ptr.
+        let root2 = &*exposed_ptr;
+        // Stack: Unknown(<N), SRO(N), SRO(N+1)
+        // And we test that it is read-only by doing a conflicting write.
+        // (The write is still fine, using the `root as *mut i32` provenance which got exposed.)
+        *exposed_ptr = 0;
+        // Stack: Unknown(<N)
+        let _val = *root2; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_write_despite_exposed1.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_write_despite_exposed1.stderr
new file mode 100644
index 000000000000..87ddf61d7586
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_write_despite_exposed1.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/illegal_write_despite_exposed1.rs:LL:CC
+   |
+LL |         let _val = *root2;
+   |                    ^^^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/illegal_write_despite_exposed1.rs:LL:CC
+   |
+LL |         let root2 = &*exposed_ptr;
+   |                     ^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/illegal_write_despite_exposed1.rs:LL:CC
+   |
+LL |         *exposed_ptr = 0;
+   |         ^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/illegal_write_despite_exposed1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/interior_mut1.rs b/src/tools/miri/tests/fail/stacked_borrows/interior_mut1.rs
new file mode 100644
index 000000000000..6911238fc53e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/interior_mut1.rs
@@ -0,0 +1,17 @@
+use std::cell::UnsafeCell;
+
+fn main() {
+    unsafe {
+        let c = &UnsafeCell::new(UnsafeCell::new(0));
+        let inner_uniq = &mut *c.get();
+        // stack: [c: SharedReadWrite, inner_uniq: Unique]
+
+        let inner_shr = &*inner_uniq; // adds a SharedReadWrite
+        // stack: [c: SharedReadWrite, inner_uniq: Unique, inner_shr: SharedReadWrite]
+
+        *c.get() = UnsafeCell::new(1); // invalidates inner_shr
+        // stack: [c: SharedReadWrite]
+
+        let _val = *inner_shr.get(); //~ ERROR: /retag .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/interior_mut1.stderr b/src/tools/miri/tests/fail/stacked_borrows/interior_mut1.stderr
new file mode 100644
index 000000000000..1d68727c82af
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/interior_mut1.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/interior_mut1.rs:LL:CC
+   |
+LL |         let _val = *inner_shr.get();
+   |                     ^^^^^^^^^^^^^^^
+   |                     |
+   |                     trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                     this error occurs as part of retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/interior_mut1.rs:LL:CC
+   |
+LL |         let inner_shr = &*inner_uniq; // adds a SharedReadWrite
+   |                         ^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/interior_mut1.rs:LL:CC
+   |
+LL |         *c.get() = UnsafeCell::new(1); // invalidates inner_shr
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/interior_mut1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/interior_mut2.rs b/src/tools/miri/tests/fail/stacked_borrows/interior_mut2.rs
new file mode 100644
index 000000000000..5e9d177cd038
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/interior_mut2.rs
@@ -0,0 +1,30 @@
+use std::cell::UnsafeCell;
+use std::mem;
+
+// Like `&mut *x.get()`, but without intermediate raw pointers.
+#[allow(mutable_transmutes)]
+unsafe fn unsafe_cell_get<T>(x: &UnsafeCell<T>) -> &'static mut T {
+    mem::transmute(x)
+}
+
+fn main() {
+    unsafe {
+        let c = &UnsafeCell::new(UnsafeCell::new(0));
+        let inner_uniq = &mut *c.get();
+        let inner_shr = &*inner_uniq;
+        // stack: [c: SharedReadWrite, inner_uniq: Unique, inner_shr: SharedReadWrite]
+
+        let _val = c.get().read(); // invalidates inner_uniq
+        // stack: [c: SharedReadWrite, inner_uniq: Disabled, inner_shr: SharedReadWrite]
+
+        // We have to be careful not to add any raw pointers above inner_uniq in
+        // the stack, hence the use of unsafe_cell_get.
+        let _val = *unsafe_cell_get(inner_shr); // this still works
+
+        *c.get() = UnsafeCell::new(0); // now inner_shr gets invalidated
+        // stack: [c: SharedReadWrite]
+
+        // now this does not work any more
+        let _val = *inner_shr.get(); //~ ERROR: /retag .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/interior_mut2.stderr b/src/tools/miri/tests/fail/stacked_borrows/interior_mut2.stderr
new file mode 100644
index 000000000000..8a3357142261
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/interior_mut2.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/interior_mut2.rs:LL:CC
+   |
+LL |         let _val = *inner_shr.get();
+   |                     ^^^^^^^^^^^^^^^
+   |                     |
+   |                     trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                     this error occurs as part of retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/interior_mut2.rs:LL:CC
+   |
+LL |         let inner_shr = &*inner_uniq;
+   |                         ^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/interior_mut2.rs:LL:CC
+   |
+LL |         *c.get() = UnsafeCell::new(0); // now inner_shr gets invalidated
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/interior_mut2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector1.rs b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector1.rs
new file mode 100644
index 000000000000..d0f43510c28f
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector1.rs
@@ -0,0 +1,13 @@
+fn inner(x: *mut i32, _y: &mut i32) {
+    // If `x` and `y` alias, retagging is fine with this... but we really
+    // shouldn't be allowed to use `x` at all because `y` was assumed to be
+    // unique for the duration of this call.
+    let _val = unsafe { *x }; //~ ERROR: protect
+}
+
+fn main() {
+    let mut x = 0;
+    let xraw = &mut x as *mut _;
+    let xref = unsafe { &mut *xraw };
+    inner(xraw, xref);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector1.stderr b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector1.stderr
new file mode 100644
index 000000000000..f87bd2319abd
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector1.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/invalidate_against_protector1.rs:LL:CC
+   |
+LL |     let _val = unsafe { *x };
+   |                         ^^ not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/invalidate_against_protector1.rs:LL:CC
+   |
+LL |     let xraw = &mut x as *mut _;
+   |                ^^^^^^
+help: <TAG> is this argument
+  --> $DIR/invalidate_against_protector1.rs:LL:CC
+   |
+LL | fn inner(x: *mut i32, _y: &mut i32) {
+   |                       ^^
+   = note: BACKTRACE:
+   = note: inside `inner` at $DIR/invalidate_against_protector1.rs:LL:CC
+note: inside `main` at $DIR/invalidate_against_protector1.rs:LL:CC
+  --> $DIR/invalidate_against_protector1.rs:LL:CC
+   |
+LL |     inner(xraw, xref);
+   |     ^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector2.rs b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector2.rs
new file mode 100644
index 000000000000..f4e767302fd0
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector2.rs
@@ -0,0 +1,13 @@
+fn inner(x: *mut i32, _y: &i32) {
+    // If `x` and `y` alias, retagging is fine with this... but we really
+    // shouldn't be allowed to write to `x` at all because `y` was assumed to be
+    // immutable for the duration of this call.
+    unsafe { *x = 0 }; //~ ERROR: protect
+}
+
+fn main() {
+    let mut x = 0;
+    let xraw = &mut x as *mut _;
+    let xref = unsafe { &*xraw };
+    inner(xraw, xref);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector2.stderr b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector2.stderr
new file mode 100644
index 000000000000..07c51a39b825
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector2.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/invalidate_against_protector2.rs:LL:CC
+   |
+LL |     unsafe { *x = 0 };
+   |              ^^^^^^ not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/invalidate_against_protector2.rs:LL:CC
+   |
+LL |     let xraw = &mut x as *mut _;
+   |                ^^^^^^
+help: <TAG> is this argument
+  --> $DIR/invalidate_against_protector2.rs:LL:CC
+   |
+LL | fn inner(x: *mut i32, _y: &i32) {
+   |                       ^^
+   = note: BACKTRACE:
+   = note: inside `inner` at $DIR/invalidate_against_protector2.rs:LL:CC
+note: inside `main` at $DIR/invalidate_against_protector2.rs:LL:CC
+  --> $DIR/invalidate_against_protector2.rs:LL:CC
+   |
+LL |     inner(xraw, xref);
+   |     ^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector3.rs b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector3.rs
new file mode 100644
index 000000000000..634eb97217c6
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector3.rs
@@ -0,0 +1,15 @@
+use std::alloc::{alloc, Layout};
+
+fn inner(x: *mut i32, _y: &i32) {
+    // If `x` and `y` alias, retagging is fine with this... but we really
+    // shouldn't be allowed to write to `x` at all because `y` was assumed to be
+    // immutable for the duration of this call.
+    unsafe { *x = 0 }; //~ ERROR: protect
+}
+
+fn main() {
+    unsafe {
+        let ptr = alloc(Layout::for_value(&0i32)) as *mut i32;
+        inner(ptr, &*ptr);
+    };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector3.stderr b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector3.stderr
new file mode 100644
index 000000000000..afda15ea160e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/invalidate_against_protector3.stderr
@@ -0,0 +1,30 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+  --> $DIR/invalidate_against_protector3.rs:LL:CC
+   |
+LL |     unsafe { *x = 0 };
+   |              ^^^^^^ not granting access to tag <TAG> because that would remove [SharedReadOnly for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created here, as the base tag for ALLOC
+  --> $DIR/invalidate_against_protector3.rs:LL:CC
+   |
+LL |         let ptr = alloc(Layout::for_value(&0i32)) as *mut i32;
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> is this argument
+  --> $DIR/invalidate_against_protector3.rs:LL:CC
+   |
+LL | fn inner(x: *mut i32, _y: &i32) {
+   |                       ^^
+   = note: BACKTRACE:
+   = note: inside `inner` at $DIR/invalidate_against_protector3.rs:LL:CC
+note: inside `main` at $DIR/invalidate_against_protector3.rs:LL:CC
+  --> $DIR/invalidate_against_protector3.rs:LL:CC
+   |
+LL |         inner(ptr, &*ptr);
+   |         ^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-1.rs b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-1.rs
new file mode 100644
index 000000000000..1e44cc6c800e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-1.rs
@@ -0,0 +1,8 @@
+//@error-pattern: pointer to 4 bytes starting at offset 0 is out-of-bounds
+
+fn main() {
+    unsafe {
+        let ptr = Box::into_raw(Box::new(0u16));
+        drop(Box::from_raw(ptr as *mut u32));
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-1.stderr b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-1.stderr
new file mode 100644
index 000000000000..16c8810a8e6d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-1.stderr
@@ -0,0 +1,21 @@
+error: Undefined Behavior: out-of-bounds pointer use: ALLOC has size 2, so pointer to 4 bytes starting at offset 0 is out-of-bounds
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
+   |
+LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: ALLOC has size 2, so pointer to 4 bytes starting at offset 0 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::boxed::Box::<u32>::from_raw_in` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+   = note: inside `std::boxed::Box::<u32>::from_raw` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+note: inside `main` at $DIR/issue-miri-1050-1.rs:LL:CC
+  --> $DIR/issue-miri-1050-1.rs:LL:CC
+   |
+LL |         drop(Box::from_raw(ptr as *mut u32));
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-2.rs b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-2.rs
new file mode 100644
index 000000000000..6e90559a9ef5
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-2.rs
@@ -0,0 +1,9 @@
+//@error-pattern: is a dangling pointer
+use std::ptr::NonNull;
+
+fn main() {
+    unsafe {
+        let ptr = NonNull::<i32>::dangling();
+        drop(Box::from_raw(ptr.as_ptr()));
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-2.stderr b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-2.stderr
new file mode 100644
index 000000000000..d57e7662e504
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/issue-miri-1050-2.stderr
@@ -0,0 +1,21 @@
+error: Undefined Behavior: out-of-bounds pointer use: 0x4[noalloc] is a dangling pointer (it has no provenance)
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
+   |
+LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: 0x4[noalloc] is a dangling pointer (it has no provenance)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `std::boxed::Box::<i32>::from_raw_in` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+   = note: inside `std::boxed::Box::<i32>::from_raw` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+note: inside `main` at $DIR/issue-miri-1050-2.rs:LL:CC
+  --> $DIR/issue-miri-1050-2.rs:LL:CC
+   |
+LL |         drop(Box::from_raw(ptr.as_ptr()));
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/load_invalid_mut.rs b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_mut.rs
new file mode 100644
index 000000000000..5c99c82da6d6
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_mut.rs
@@ -0,0 +1,12 @@
+// Make sure we catch this even without validation
+//@compile-flags: -Zmiri-disable-validation
+
+// Make sure that we cannot load from memory a `&mut` that got already invalidated.
+fn main() {
+    let x = &mut 42;
+    let xraw = x as *mut _;
+    let xref = unsafe { &mut *xraw };
+    let xref_in_mem = Box::new(xref);
+    let _val = unsafe { *xraw }; // invalidate xref
+    let _val = *xref_in_mem; //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/load_invalid_mut.stderr b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_mut.stderr
new file mode 100644
index 000000000000..08dc171c9eef
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_mut.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for Unique permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/load_invalid_mut.rs:LL:CC
+   |
+LL |     let _val = *xref_in_mem;
+   |                ^^^^^^^^^^^^
+   |                |
+   |                trying to retag from <TAG> for Unique permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/load_invalid_mut.rs:LL:CC
+   |
+LL |     let xref_in_mem = Box::new(xref);
+   |                       ^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/load_invalid_mut.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw }; // invalidate xref
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/load_invalid_mut.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/load_invalid_shr.rs b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_shr.rs
new file mode 100644
index 000000000000..8f94cc07a24f
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_shr.rs
@@ -0,0 +1,12 @@
+// Make sure we catch this even without validation
+//@compile-flags: -Zmiri-disable-validation
+
+// Make sure that we cannot load from memory a `&` that got already invalidated.
+fn main() {
+    let x = &mut 42;
+    let xraw = x as *mut _;
+    let xref = unsafe { &*xraw };
+    let xref_in_mem = Box::new(xref);
+    unsafe { *xraw = 42 }; // unfreeze
+    let _val = *xref_in_mem; //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/load_invalid_shr.stderr b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_shr.stderr
new file mode 100644
index 000000000000..50bbed2b295c
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/load_invalid_shr.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/load_invalid_shr.rs:LL:CC
+   |
+LL |     let _val = *xref_in_mem;
+   |                ^^^^^^^^^^^^
+   |                |
+   |                trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/load_invalid_shr.rs:LL:CC
+   |
+LL |     let xref_in_mem = Box::new(xref);
+   |                       ^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/load_invalid_shr.rs:LL:CC
+   |
+LL |     unsafe { *xraw = 42 }; // unfreeze
+   |              ^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/load_invalid_shr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation1.rs b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation1.rs
new file mode 100644
index 000000000000..f6fcdf1acdd2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation1.rs
@@ -0,0 +1,33 @@
+fn demo_mut_advanced_unique(our: &mut i32) -> i32 {
+    unknown_code_1(&*our);
+
+    // This "re-asserts" uniqueness of the reference: After writing, we know
+    // our tag is at the top of the stack.
+    *our = 5;
+
+    unknown_code_2();
+
+    // We know this will return 5
+    *our
+}
+
+// Now comes the evil context
+use std::ptr;
+
+static mut LEAK: *mut i32 = ptr::null_mut();
+
+fn unknown_code_1(x: &i32) {
+    unsafe {
+        LEAK = x as *const _ as *mut _;
+    }
+}
+
+fn unknown_code_2() {
+    unsafe {
+        *LEAK = 7; //~ ERROR: /write access .* tag does not exist in the borrow stack/
+    }
+}
+
+fn main() {
+    demo_mut_advanced_unique(&mut 0);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation1.stderr b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation1.stderr
new file mode 100644
index 000000000000..1c7f8e12d3d7
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation1.stderr
@@ -0,0 +1,38 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/mut_exclusive_violation1.rs:LL:CC
+   |
+LL |         *LEAK = 7;
+   |         ^^^^^^^^^
+   |         |
+   |         attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |         this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/mut_exclusive_violation1.rs:LL:CC
+   |
+LL |         LEAK = x as *const _ as *mut _;
+   |                ^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/mut_exclusive_violation1.rs:LL:CC
+   |
+LL |     *our = 5;
+   |     ^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `unknown_code_2` at $DIR/mut_exclusive_violation1.rs:LL:CC
+note: inside `demo_mut_advanced_unique` at $DIR/mut_exclusive_violation1.rs:LL:CC
+  --> $DIR/mut_exclusive_violation1.rs:LL:CC
+   |
+LL |     unknown_code_2();
+   |     ^^^^^^^^^^^^^^^^
+note: inside `main` at $DIR/mut_exclusive_violation1.rs:LL:CC
+  --> $DIR/mut_exclusive_violation1.rs:LL:CC
+   |
+LL |     demo_mut_advanced_unique(&mut 0);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation2.rs b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation2.rs
new file mode 100644
index 000000000000..2305ce746512
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation2.rs
@@ -0,0 +1,12 @@
+use std::ptr::NonNull;
+
+fn main() {
+    unsafe {
+        let x = &mut 0;
+        let mut ptr1 = NonNull::from(x);
+        let mut ptr2 = ptr1.clone();
+        let raw1 = ptr1.as_mut();
+        let _raw2 = ptr2.as_mut();
+        let _val = *raw1; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation2.stderr b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation2.stderr
new file mode 100644
index 000000000000..43b5325fc541
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/mut_exclusive_violation2.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/mut_exclusive_violation2.rs:LL:CC
+   |
+LL |         let _val = *raw1;
+   |                    ^^^^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/mut_exclusive_violation2.rs:LL:CC
+   |
+LL |         let raw1 = ptr1.as_mut();
+   |                    ^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique retag
+  --> $DIR/mut_exclusive_violation2.rs:LL:CC
+   |
+LL |         let _raw2 = ptr2.as_mut();
+   |                     ^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/mut_exclusive_violation2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/newtype_retagging.rs b/src/tools/miri/tests/fail/stacked_borrows/newtype_retagging.rs
new file mode 100644
index 000000000000..6e7413cff5d4
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/newtype_retagging.rs
@@ -0,0 +1,19 @@
+//@compile-flags: -Zmiri-retag-fields
+//@error-pattern: which is protected
+struct Newtype<'a>(&'a mut i32);
+
+fn dealloc_while_running(_n: Newtype<'_>, dealloc: impl FnOnce()) {
+    dealloc();
+}
+
+// Make sure that we protect references inside structs.
+fn main() {
+    let ptr = Box::into_raw(Box::new(0i32));
+    #[rustfmt::skip] // I like my newlines
+    unsafe {
+        dealloc_while_running(
+            Newtype(&mut *ptr),
+            || drop(Box::from_raw(ptr)),
+        )
+    };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/newtype_retagging.stderr b/src/tools/miri/tests/fail/stacked_borrows/newtype_retagging.stderr
new file mode 100644
index 000000000000..06a9b86c6f45
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/newtype_retagging.stderr
@@ -0,0 +1,44 @@
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
+   |
+LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/newtype_retagging.rs:LL:CC
+   |
+LL |     let ptr = Box::into_raw(Box::new(0i32));
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> is this argument
+  --> $DIR/newtype_retagging.rs:LL:CC
+   |
+LL | fn dealloc_while_running(_n: Newtype<'_>, dealloc: impl FnOnce()) {
+   |                          ^^
+   = note: BACKTRACE:
+   = note: inside `std::boxed::Box::<i32>::from_raw_in` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+   = note: inside `std::boxed::Box::<i32>::from_raw` at RUSTLIB/alloc/src/boxed.rs:LL:CC
+note: inside closure at $DIR/newtype_retagging.rs:LL:CC
+  --> $DIR/newtype_retagging.rs:LL:CC
+   |
+LL |             || drop(Box::from_raw(ptr)),
+   |                     ^^^^^^^^^^^^^^^^^^
+note: inside `dealloc_while_running::<[closure@$DIR/newtype_retagging.rs:LL:CC]>` at $DIR/newtype_retagging.rs:LL:CC
+  --> $DIR/newtype_retagging.rs:LL:CC
+   |
+LL |     dealloc();
+   |     ^^^^^^^^^
+note: inside `main` at $DIR/newtype_retagging.rs:LL:CC
+  --> $DIR/newtype_retagging.rs:LL:CC
+   |
+LL | /         dealloc_while_running(
+LL | |             Newtype(&mut *ptr),
+LL | |             || drop(Box::from_raw(ptr)),
+LL | |         )
+   | |_________^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/outdated_local.rs b/src/tools/miri/tests/fail/stacked_borrows/outdated_local.rs
new file mode 100644
index 000000000000..4262157d1e3d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/outdated_local.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let mut x = 0;
+    let y: *const i32 = &x;
+    x = 1; // this invalidates y by reactivating the lowermost uniq borrow for this local
+
+    assert_eq!(unsafe { *y }, 1); //~ ERROR: /read access .* tag does not exist in the borrow stack/
+
+    assert_eq!(x, 1);
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/outdated_local.stderr b/src/tools/miri/tests/fail/stacked_borrows/outdated_local.stderr
new file mode 100644
index 000000000000..8c2bba539188
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/outdated_local.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/outdated_local.rs:LL:CC
+   |
+LL |     assert_eq!(unsafe { *y }, 1);
+   |                         ^^
+   |                         |
+   |                         attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                         this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/outdated_local.rs:LL:CC
+   |
+LL |     let y: *const i32 = &x;
+   |                         ^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/outdated_local.rs:LL:CC
+   |
+LL |     x = 1; // this invalidates y by reactivating the lowermost uniq borrow for this local
+   |     ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/outdated_local.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_mut.rs b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_mut.rs
new file mode 100644
index 000000000000..8db2c149b17e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_mut.rs
@@ -0,0 +1,10 @@
+// Make sure that we cannot pass by argument a `&mut` that got already invalidated.
+fn foo(_: &mut i32) {}
+
+fn main() {
+    let x = &mut 42;
+    let xraw = x as *mut _;
+    let xref = unsafe { &mut *xraw };
+    let _val = unsafe { *xraw }; // invalidate xref
+    foo(xref); //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_mut.stderr b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_mut.stderr
new file mode 100644
index 000000000000..d7ab930aa378
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_mut.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/pass_invalid_mut.rs:LL:CC
+   |
+LL |     foo(xref);
+   |         ^^^^
+   |         |
+   |         trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |         this error occurs as part of two-phase retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/pass_invalid_mut.rs:LL:CC
+   |
+LL |     let xref = unsafe { &mut *xraw };
+   |                         ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/pass_invalid_mut.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw }; // invalidate xref
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/pass_invalid_mut.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_shr.rs b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_shr.rs
new file mode 100644
index 000000000000..903c2733107b
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_shr.rs
@@ -0,0 +1,10 @@
+// Make sure that we cannot pass by argument a `&` that got already invalidated.
+fn foo(_: &i32) {}
+
+fn main() {
+    let x = &mut 42;
+    let xraw = x as *mut _;
+    let xref = unsafe { &*xraw };
+    unsafe { *xraw = 42 }; // unfreeze
+    foo(xref); //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_shr.stderr b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_shr.stderr
new file mode 100644
index 000000000000..c14b35c75c83
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/pass_invalid_shr.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/pass_invalid_shr.rs:LL:CC
+   |
+LL |     foo(xref);
+   |         ^^^^
+   |         |
+   |         trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |         this error occurs as part of retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/pass_invalid_shr.rs:LL:CC
+   |
+LL |     let xref = unsafe { &*xraw };
+   |                         ^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a write access
+  --> $DIR/pass_invalid_shr.rs:LL:CC
+   |
+LL |     unsafe { *xraw = 42 }; // unfreeze
+   |              ^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/pass_invalid_shr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/pointer_smuggling.rs b/src/tools/miri/tests/fail/stacked_borrows/pointer_smuggling.rs
new file mode 100644
index 000000000000..e1c3ff492898
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/pointer_smuggling.rs
@@ -0,0 +1,20 @@
+static mut PTR: *mut u8 = 0 as *mut _;
+
+fn fun1(x: &mut u8) {
+    unsafe {
+        PTR = x;
+    }
+}
+
+fn fun2() {
+    // Now we use a pointer we are not allowed to use
+    let _x = unsafe { *PTR }; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+}
+
+fn main() {
+    let mut val = 0;
+    let val = &mut val;
+    fun1(val);
+    *val = 2; // this invalidates any raw ptrs `fun1` might have created.
+    fun2(); // if they now use a raw ptr they break our reference
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/pointer_smuggling.stderr b/src/tools/miri/tests/fail/stacked_borrows/pointer_smuggling.stderr
new file mode 100644
index 000000000000..6415af1e18bb
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/pointer_smuggling.stderr
@@ -0,0 +1,33 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/pointer_smuggling.rs:LL:CC
+   |
+LL |     let _x = unsafe { *PTR };
+   |                       ^^^^
+   |                       |
+   |                       attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                       this error occurs as part of an access at ALLOC[0x0..0x1]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x1]
+  --> $DIR/pointer_smuggling.rs:LL:CC
+   |
+LL |         PTR = x;
+   |               ^
+help: <TAG> was later invalidated at offsets [0x0..0x1] by a write access
+  --> $DIR/pointer_smuggling.rs:LL:CC
+   |
+LL |     *val = 2; // this invalidates any raw ptrs `fun1` might have created.
+   |     ^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `fun2` at $DIR/pointer_smuggling.rs:LL:CC
+note: inside `main` at $DIR/pointer_smuggling.rs:LL:CC
+  --> $DIR/pointer_smuggling.rs:LL:CC
+   |
+LL |     fun2(); // if they now use a raw ptr they break our reference
+   |     ^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/raw_tracking.rs b/src/tools/miri/tests/fail/stacked_borrows/raw_tracking.rs
new file mode 100644
index 000000000000..15306e0825b2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/raw_tracking.rs
@@ -0,0 +1,11 @@
+//! This demonstrates a provenance problem that requires tracking of raw pointers to be detected.
+
+fn main() {
+    let mut l = 13;
+    let raw1 = &mut l as *mut _;
+    let raw2 = &mut l as *mut _; // invalidates raw1
+    // Without raw pointer tracking, Stacked Borrows cannot distinguish raw1 and raw2, and thus
+    // fails to realize that raw1 should not be used any more.
+    unsafe { *raw1 = 13 }; //~ ERROR: /write access .* tag does not exist in the borrow stack/
+    unsafe { *raw2 = 13 };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/raw_tracking.stderr b/src/tools/miri/tests/fail/stacked_borrows/raw_tracking.stderr
new file mode 100644
index 000000000000..d75934445e6d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/raw_tracking.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/raw_tracking.rs:LL:CC
+   |
+LL |     unsafe { *raw1 = 13 };
+   |              ^^^^^^^^^^
+   |              |
+   |              attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |              this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x0..0x4]
+  --> $DIR/raw_tracking.rs:LL:CC
+   |
+LL |     let raw1 = &mut l as *mut _;
+   |                ^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique retag
+  --> $DIR/raw_tracking.rs:LL:CC
+   |
+LL |     let raw2 = &mut l as *mut _; // invalidates raw1
+   |                ^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/raw_tracking.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut.rs b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut.rs
new file mode 100644
index 000000000000..7d9a6f11aff9
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut.rs
@@ -0,0 +1,11 @@
+// Make sure that we cannot return a `&mut` that got already invalidated.
+fn foo(x: &mut (i32, i32)) -> &mut i32 {
+    let xraw = x as *mut (i32, i32);
+    let ret = unsafe { &mut (*xraw).1 };
+    let _val = unsafe { *xraw }; // invalidate xref
+    ret //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
+
+fn main() {
+    foo(&mut (1, 2));
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut.stderr b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut.stderr
new file mode 100644
index 000000000000..9deb0c41742f
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut.stderr
@@ -0,0 +1,33 @@
+error: Undefined Behavior: trying to retag from <TAG> for Unique permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/return_invalid_mut.rs:LL:CC
+   |
+LL |     ret
+   |     ^^^
+   |     |
+   |     trying to retag from <TAG> for Unique permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |     this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x4..0x8]
+  --> $DIR/return_invalid_mut.rs:LL:CC
+   |
+LL |     let ret = unsafe { &mut (*xraw).1 };
+   |                        ^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x8] by a read access
+  --> $DIR/return_invalid_mut.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw }; // invalidate xref
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `foo` at $DIR/return_invalid_mut.rs:LL:CC
+note: inside `main` at $DIR/return_invalid_mut.rs:LL:CC
+  --> $DIR/return_invalid_mut.rs:LL:CC
+   |
+LL |     foo(&mut (1, 2));
+   |     ^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_option.rs b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_option.rs
new file mode 100644
index 000000000000..7fa9cf77d44b
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_option.rs
@@ -0,0 +1,16 @@
+// Make sure that we cannot return a `&mut` that got already invalidated, not even in an `Option`.
+// Due to shallow reborrowing, the error only surfaces when we look into the `Option`.
+fn foo(x: &mut (i32, i32)) -> Option<&mut i32> {
+    let xraw = x as *mut (i32, i32);
+    let ret = unsafe { &mut (*xraw).1 }; // let-bind to avoid 2phase
+    let ret = Some(ret);
+    let _val = unsafe { *xraw }; // invalidate xref
+    ret
+}
+
+fn main() {
+    match foo(&mut (1, 2)) {
+        Some(_x) => {} //~ ERROR: /retag .* tag does not exist in the borrow stack/
+        None => {}
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_option.stderr b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_option.stderr
new file mode 100644
index 000000000000..1068c286c62f
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_option.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for Unique permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/return_invalid_mut_option.rs:LL:CC
+   |
+LL |         Some(_x) => {}
+   |              ^^
+   |              |
+   |              trying to retag from <TAG> for Unique permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |              this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x4..0x8]
+  --> $DIR/return_invalid_mut_option.rs:LL:CC
+   |
+LL |     let ret = Some(ret);
+   |                    ^^^
+help: <TAG> was later invalidated at offsets [0x0..0x8] by a read access
+  --> $DIR/return_invalid_mut_option.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw }; // invalidate xref
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/return_invalid_mut_option.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_tuple.rs b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_tuple.rs
new file mode 100644
index 000000000000..c94fef90542f
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_tuple.rs
@@ -0,0 +1,12 @@
+// Make sure that we cannot return a `&mut` that got already invalidated, not even in a tuple.
+// Due to shallow reborrowing, the error only surfaces when we look into the tuple.
+fn foo(x: &mut (i32, i32)) -> (&mut i32,) {
+    let xraw = x as *mut (i32, i32);
+    let ret = (unsafe { &mut (*xraw).1 },);
+    let _val = unsafe { *xraw }; // invalidate xref
+    ret
+}
+
+fn main() {
+    foo(&mut (1, 2)).0; //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_tuple.stderr b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_tuple.stderr
new file mode 100644
index 000000000000..79de9b668cf2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_mut_tuple.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for Unique permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/return_invalid_mut_tuple.rs:LL:CC
+   |
+LL |     foo(&mut (1, 2)).0;
+   |     ^^^^^^^^^^^^^^^^^^
+   |     |
+   |     trying to retag from <TAG> for Unique permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |     this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x4..0x8]
+  --> $DIR/return_invalid_mut_tuple.rs:LL:CC
+   |
+LL |     let ret = (unsafe { &mut (*xraw).1 },);
+   |                         ^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x8] by a read access
+  --> $DIR/return_invalid_mut_tuple.rs:LL:CC
+   |
+LL |     let _val = unsafe { *xraw }; // invalidate xref
+   |                         ^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/return_invalid_mut_tuple.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr.rs b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr.rs
new file mode 100644
index 000000000000..45526498dadf
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr.rs
@@ -0,0 +1,11 @@
+// Make sure that we cannot return a `&` that got already invalidated.
+fn foo(x: &mut (i32, i32)) -> &i32 {
+    let xraw = x as *mut (i32, i32);
+    let ret = unsafe { &(*xraw).1 };
+    unsafe { *xraw = (42, 23) }; // unfreeze
+    ret //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
+
+fn main() {
+    foo(&mut (1, 2));
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr.stderr b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr.stderr
new file mode 100644
index 000000000000..dd651517c2fb
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr.stderr
@@ -0,0 +1,33 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/return_invalid_shr.rs:LL:CC
+   |
+LL |     ret
+   |     ^^^
+   |     |
+   |     trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |     this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
+  --> $DIR/return_invalid_shr.rs:LL:CC
+   |
+LL |     let ret = unsafe { &(*xraw).1 };
+   |                        ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+  --> $DIR/return_invalid_shr.rs:LL:CC
+   |
+LL |     unsafe { *xraw = (42, 23) }; // unfreeze
+   |              ^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `foo` at $DIR/return_invalid_shr.rs:LL:CC
+note: inside `main` at $DIR/return_invalid_shr.rs:LL:CC
+  --> $DIR/return_invalid_shr.rs:LL:CC
+   |
+LL |     foo(&mut (1, 2));
+   |     ^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_option.rs b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_option.rs
new file mode 100644
index 000000000000..3a028ceed86a
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_option.rs
@@ -0,0 +1,15 @@
+// Make sure that we cannot return a `&` that got already invalidated, not even in an `Option`.
+// Due to shallow reborrowing, the error only surfaces when we look into the `Option`.
+fn foo(x: &mut (i32, i32)) -> Option<&i32> {
+    let xraw = x as *mut (i32, i32);
+    let ret = Some(unsafe { &(*xraw).1 });
+    unsafe { *xraw = (42, 23) }; // unfreeze
+    ret
+}
+
+fn main() {
+    match foo(&mut (1, 2)) {
+        Some(_x) => {} //~ ERROR: /retag .* tag does not exist in the borrow stack/
+        None => {}
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_option.stderr b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_option.stderr
new file mode 100644
index 000000000000..f45456305db2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_option.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/return_invalid_shr_option.rs:LL:CC
+   |
+LL |         Some(_x) => {}
+   |              ^^
+   |              |
+   |              trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |              this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
+  --> $DIR/return_invalid_shr_option.rs:LL:CC
+   |
+LL |     let ret = Some(unsafe { &(*xraw).1 });
+   |                             ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+  --> $DIR/return_invalid_shr_option.rs:LL:CC
+   |
+LL |     unsafe { *xraw = (42, 23) }; // unfreeze
+   |              ^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/return_invalid_shr_option.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_tuple.rs b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_tuple.rs
new file mode 100644
index 000000000000..e4536626dbf2
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_tuple.rs
@@ -0,0 +1,12 @@
+// Make sure that we cannot return a `&` that got already invalidated, not even in a tuple.
+// Due to shallow reborrowing, the error only surfaces when we look into the tuple.
+fn foo(x: &mut (i32, i32)) -> (&i32,) {
+    let xraw = x as *mut (i32, i32);
+    let ret = (unsafe { &(*xraw).1 },);
+    unsafe { *xraw = (42, 23) }; // unfreeze
+    ret
+}
+
+fn main() {
+    foo(&mut (1, 2)).0; //~ ERROR: /retag .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_tuple.stderr b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_tuple.stderr
new file mode 100644
index 000000000000..2e41f505bb9d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/return_invalid_shr_tuple.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> $DIR/return_invalid_shr_tuple.rs:LL:CC
+   |
+LL |     foo(&mut (1, 2)).0;
+   |     ^^^^^^^^^^^^^^^^^^
+   |     |
+   |     trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |     this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x4..0x8]
+  --> $DIR/return_invalid_shr_tuple.rs:LL:CC
+   |
+LL |     let ret = (unsafe { &(*xraw).1 },);
+   |                         ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x8] by a write access
+  --> $DIR/return_invalid_shr_tuple.rs:LL:CC
+   |
+LL |     unsafe { *xraw = (42, 23) }; // unfreeze
+   |              ^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/return_invalid_shr_tuple.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak1.rs b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak1.rs
new file mode 100644
index 000000000000..2450ec4b4a1d
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak1.rs
@@ -0,0 +1,16 @@
+// We want to test that granting a SharedReadWrite will be added
+// *below* an already granted Unique -- so writing to
+// the SharedReadWrite will invalidate the Unique.
+
+use std::cell::Cell;
+use std::mem;
+
+fn main() {
+    unsafe {
+        let x = &mut Cell::new(0);
+        let y: &mut Cell<i32> = mem::transmute(&mut *x); // launder lifetime
+        let shr_rw = &*x; // thanks to interior mutability this will be a SharedReadWrite
+        shr_rw.set(1);
+        y.get_mut(); //~ ERROR: /retag .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak1.stderr b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak1.stderr
new file mode 100644
index 000000000000..3a139c3ab212
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak1.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/shared_rw_borrows_are_weak1.rs:LL:CC
+   |
+LL |         y.get_mut();
+   |         ^^^^^^^^^^^
+   |         |
+   |         trying to retag from <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |         this error occurs as part of two-phase retag at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/shared_rw_borrows_are_weak1.rs:LL:CC
+   |
+LL |         let y: &mut Cell<i32> = mem::transmute(&mut *x); // launder lifetime
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a Unique retag
+  --> $DIR/shared_rw_borrows_are_weak1.rs:LL:CC
+   |
+LL |         shr_rw.set(1);
+   |         ^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/shared_rw_borrows_are_weak1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak2.rs b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak2.rs
new file mode 100644
index 000000000000..012e9561ca84
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak2.rs
@@ -0,0 +1,17 @@
+// We want to test that granting a SharedReadWrite will be added
+// *below* an already granted SharedReadWrite -- so writing to
+// the SharedReadWrite will invalidate the SharedReadWrite.
+//@normalize-stderr-test: "0x[0-9a-fA-F]+" -> "$$HEX"
+
+use std::cell::RefCell;
+use std::mem;
+
+fn main() {
+    unsafe {
+        let x = &mut RefCell::new(0);
+        let y: &i32 = mem::transmute(&*x.borrow()); // launder lifetime
+        let shr_rw = &*x; // thanks to interior mutability this will be a SharedReadWrite
+        shr_rw.replace(1);
+        let _val = *y; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak2.stderr b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak2.stderr
new file mode 100644
index 000000000000..0609a73e7931
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/shared_rw_borrows_are_weak2.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[$HEX], but that tag does not exist in the borrow stack for this location
+  --> $DIR/shared_rw_borrows_are_weak2.rs:LL:CC
+   |
+LL |         let _val = *y;
+   |                    ^^
+   |                    |
+   |                    attempting a read access using <TAG> at ALLOC[$HEX], but that tag does not exist in the borrow stack for this location
+   |                    this error occurs as part of an access at ALLOC[$HEX..$HEX]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [$HEX..$HEX]
+  --> $DIR/shared_rw_borrows_are_weak2.rs:LL:CC
+   |
+LL |         let y: &i32 = mem::transmute(&*x.borrow()); // launder lifetime
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [$HEX..$HEX] by a Unique retag
+  --> $DIR/shared_rw_borrows_are_weak2.rs:LL:CC
+   |
+LL |         shr_rw.replace(1);
+   |         ^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/shared_rw_borrows_are_weak2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs b/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs
new file mode 100644
index 000000000000..d1322dc6e57b
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs
@@ -0,0 +1,15 @@
+fn foo(x: &mut i32) -> i32 {
+    *x = 5;
+    unknown_code(&*x);
+    *x // must return 5
+}
+
+fn main() {
+    println!("{}", foo(&mut 0));
+}
+
+fn unknown_code(x: &i32) {
+    unsafe {
+        *(x as *const i32 as *mut i32) = 7; //~ ERROR: /write access .* only grants SharedReadOnly permission/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.stderr b/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.stderr
new file mode 100644
index 000000000000..0818d07da48e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.stderr
@@ -0,0 +1,33 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag only grants SharedReadOnly permission for this location
+  --> $DIR/shr_frozen_violation1.rs:LL:CC
+   |
+LL |         *(x as *const i32 as *mut i32) = 7;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         |
+   |         attempting a write access using <TAG> at ALLOC[0x0], but that tag only grants SharedReadOnly permission for this location
+   |         this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x4]
+  --> $DIR/shr_frozen_violation1.rs:LL:CC
+   |
+LL |         *(x as *const i32 as *mut i32) = 7;
+   |           ^
+   = note: BACKTRACE:
+   = note: inside `unknown_code` at $DIR/shr_frozen_violation1.rs:LL:CC
+note: inside `foo` at $DIR/shr_frozen_violation1.rs:LL:CC
+  --> $DIR/shr_frozen_violation1.rs:LL:CC
+   |
+LL |     unknown_code(&*x);
+   |     ^^^^^^^^^^^^^^^^^
+note: inside `main` at $DIR/shr_frozen_violation1.rs:LL:CC
+  --> $DIR/shr_frozen_violation1.rs:LL:CC
+   |
+LL |     println!("{}", foo(&mut 0));
+   |                    ^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.rs b/src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.rs
new file mode 100644
index 000000000000..84d7878b264e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.rs
@@ -0,0 +1,8 @@
+static X: usize = 5;
+
+#[allow(mutable_transmutes)]
+fn main() {
+    let _x = unsafe {
+        std::mem::transmute::<&usize, &mut usize>(&X) //~ ERROR: writing to alloc1 which is read-only
+    };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.stderr b/src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.stderr
new file mode 100644
index 000000000000..ca99a8262b8b
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: writing to ALLOC which is read-only
+  --> $DIR/static_memory_modification.rs:LL:CC
+   |
+LL |         std::mem::transmute::<&usize, &mut usize>(&X)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ writing to ALLOC which is read-only
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/static_memory_modification.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/track_caller.rs b/src/tools/miri/tests/fail/stacked_borrows/track_caller.rs
new file mode 100644
index 000000000000..3455eb4684ea
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/track_caller.rs
@@ -0,0 +1,17 @@
+// This is a copy of illegal_read1.rs, but with #[track_caller] on the test.
+// This test only checks that our diagnostics do not display the contents of callee.
+
+#[rustfmt::skip] // rustfmt bug: https://github.com/rust-lang/rustfmt/issues/5391
+fn main() {
+    let mut x = 15;
+    let xraw = &mut x as *mut _;
+    let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
+    callee(xraw);
+    let _val = *xref; // ...but any use of raw will invalidate our ref.
+    //~^ ERROR: /read access .* tag does not exist in the borrow stack/
+}
+
+#[track_caller]
+fn callee(xraw: *mut i32) {
+    let _val = unsafe { *xraw };
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/track_caller.stderr b/src/tools/miri/tests/fail/stacked_borrows/track_caller.stderr
new file mode 100644
index 000000000000..6f1d0ccd348e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/track_caller.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/track_caller.rs:LL:CC
+   |
+LL |     let _val = *xref; // ...but any use of raw will invalidate our ref.
+   |                ^^^^^
+   |                |
+   |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |                this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a Unique retag at offsets [0x0..0x4]
+  --> $DIR/track_caller.rs:LL:CC
+   |
+LL |     let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
+   |                         ^^^^^^^^^^
+help: <TAG> was later invalidated at offsets [0x0..0x4] by a read access
+  --> $DIR/track_caller.rs:LL:CC
+   |
+LL |     callee(xraw);
+   |     ^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/track_caller.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/transmute-is-no-escape.rs b/src/tools/miri/tests/fail/stacked_borrows/transmute-is-no-escape.rs
new file mode 100644
index 000000000000..233b927dfc7e
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/transmute-is-no-escape.rs
@@ -0,0 +1,14 @@
+// Make sure we cannot use raw ptrs that got transmuted from mutable references
+// (i.e, no EscapeToRaw happened).
+// We could, in principle, do EscapeToRaw lazily to allow this code, but that
+// would no alleviate the need for EscapeToRaw (see `ref_raw_int_raw` in
+// `run-pass/stacked-borrows.rs`), and thus increase overall complexity.
+use std::mem;
+
+fn main() {
+    let mut x: [i32; 2] = [42, 43];
+    let _raw: *mut i32 = unsafe { mem::transmute(&mut x[0]) };
+    // `raw` still carries a tag, so we get another pointer to the same location that does not carry a tag
+    let raw = (&mut x[1] as *mut i32).wrapping_offset(-1);
+    unsafe { *raw = 13 }; //~ ERROR: /write access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/transmute-is-no-escape.stderr b/src/tools/miri/tests/fail/stacked_borrows/transmute-is-no-escape.stderr
new file mode 100644
index 000000000000..a2ecb07fd311
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/transmute-is-no-escape.stderr
@@ -0,0 +1,23 @@
+error: Undefined Behavior: attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+  --> $DIR/transmute-is-no-escape.rs:LL:CC
+   |
+LL |     unsafe { *raw = 13 };
+   |              ^^^^^^^^^
+   |              |
+   |              attempting a write access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
+   |              this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadWrite retag at offsets [0x4..0x8]
+  --> $DIR/transmute-is-no-escape.rs:LL:CC
+   |
+LL |     let raw = (&mut x[1] as *mut i32).wrapping_offset(-1);
+   |                ^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/transmute-is-no-escape.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/unescaped_local.rs b/src/tools/miri/tests/fail/stacked_borrows/unescaped_local.rs
new file mode 100644
index 000000000000..49c0e66d8570
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/unescaped_local.rs
@@ -0,0 +1,12 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+// Make sure we cannot use raw ptrs to access a local that
+// we took the direct address of.
+fn main() {
+    let mut x = 42;
+    let raw = &mut x as *mut i32 as usize as *mut i32;
+    let _ptr = &mut x;
+    unsafe {
+        *raw = 13; //~ ERROR: /write access .* no exposed tags/
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/unescaped_local.stderr b/src/tools/miri/tests/fail/stacked_borrows/unescaped_local.stderr
new file mode 100644
index 000000000000..4deafa890005
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/unescaped_local.stderr
@@ -0,0 +1,18 @@
+error: Undefined Behavior: attempting a write access using <wildcard> at ALLOC[0x0], but no exposed tags have suitable permission in the borrow stack for this location
+  --> $DIR/unescaped_local.rs:LL:CC
+   |
+LL |         *raw = 13;
+   |         ^^^^^^^^^
+   |         |
+   |         attempting a write access using <wildcard> at ALLOC[0x0], but no exposed tags have suitable permission in the borrow stack for this location
+   |         this error occurs as part of an access at ALLOC[0x0..0x4]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unescaped_local.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/unescaped_static.rs b/src/tools/miri/tests/fail/stacked_borrows/unescaped_static.rs
new file mode 100644
index 000000000000..a25d9b5162ec
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/unescaped_static.rs
@@ -0,0 +1,7 @@
+static ARRAY: [u8; 2] = [0, 1];
+
+fn main() {
+    let ptr_to_first = &ARRAY[0] as *const u8;
+    // Illegally use this to access the 2nd element.
+    let _val = unsafe { *ptr_to_first.add(1) }; //~ ERROR: /read access .* tag does not exist in the borrow stack/
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/unescaped_static.stderr b/src/tools/miri/tests/fail/stacked_borrows/unescaped_static.stderr
new file mode 100644
index 000000000000..01a4bf4340c7
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/unescaped_static.stderr
@@ -0,0 +1,23 @@
+error: Undefined Behavior: attempting a read access using <TAG> at ALLOC[0x1], but that tag does not exist in the borrow stack for this location
+  --> $DIR/unescaped_static.rs:LL:CC
+   |
+LL |     let _val = unsafe { *ptr_to_first.add(1) };
+   |                         ^^^^^^^^^^^^^^^^^^^^
+   |                         |
+   |                         attempting a read access using <TAG> at ALLOC[0x1], but that tag does not exist in the borrow stack for this location
+   |                         this error occurs as part of an access at ALLOC[0x1..0x2]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x1]
+  --> $DIR/unescaped_static.rs:LL:CC
+   |
+LL |     let ptr_to_first = &ARRAY[0] as *const u8;
+   |                        ^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unescaped_static.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/stacked_borrows/zst_slice.rs b/src/tools/miri/tests/fail/stacked_borrows/zst_slice.rs
new file mode 100644
index 000000000000..77daa9c9811a
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/zst_slice.rs
@@ -0,0 +1,11 @@
+//@compile-flags: -Zmiri-strict-provenance
+//@error-pattern: /retag .* tag does not exist in the borrow stack/
+
+fn main() {
+    unsafe {
+        let a = [1, 2, 3];
+        let s = &a[0..0];
+        assert_eq!(s.len(), 0);
+        assert_eq!(*s.get_unchecked(1), 2);
+    }
+}
diff --git a/src/tools/miri/tests/fail/stacked_borrows/zst_slice.stderr b/src/tools/miri/tests/fail/stacked_borrows/zst_slice.stderr
new file mode 100644
index 000000000000..86f1da1f70a3
--- /dev/null
+++ b/src/tools/miri/tests/fail/stacked_borrows/zst_slice.stderr
@@ -0,0 +1,28 @@
+error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+  --> RUSTLIB/core/src/slice/mod.rs:LL:CC
+   |
+LL |         unsafe { &*index.get_unchecked(self) }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  |
+   |                  trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |                  this error occurs as part of retag at ALLOC[0x4..0x8]
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
+   = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
+help: <TAG> would have been created here, but this is a zero-size retag ([0x0..0x0]) so the tag in question does not exist anywhere
+  --> $DIR/zst_slice.rs:LL:CC
+   |
+LL |         assert_eq!(*s.get_unchecked(1), 2);
+   |                     ^^^^^^^^^^^^^^^^^^
+   = note: BACKTRACE:
+   = note: inside `core::slice::<impl [i32]>::get_unchecked::<usize>` at RUSTLIB/core/src/slice/mod.rs:LL:CC
+note: inside `main` at $DIR/zst_slice.rs:LL:CC
+  --> $DIR/zst_slice.rs:LL:CC
+   |
+LL |         assert_eq!(*s.get_unchecked(1), 2);
+   |                     ^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/static_memory_modification1.rs b/src/tools/miri/tests/fail/static_memory_modification1.rs
new file mode 100644
index 000000000000..66794e7535a4
--- /dev/null
+++ b/src/tools/miri/tests/fail/static_memory_modification1.rs
@@ -0,0 +1,12 @@
+// Stacked Borrows detects that we are casting & to &mut and so it changes why we fail
+//@compile-flags: -Zmiri-disable-stacked-borrows
+
+static X: usize = 5;
+
+#[allow(mutable_transmutes)]
+fn main() {
+    unsafe {
+        *std::mem::transmute::<&usize, &mut usize>(&X) = 6; //~ ERROR: read-only
+        assert_eq!(X, 6);
+    }
+}
diff --git a/src/tools/miri/tests/fail/static_memory_modification1.stderr b/src/tools/miri/tests/fail/static_memory_modification1.stderr
new file mode 100644
index 000000000000..5e7213ee6088
--- /dev/null
+++ b/src/tools/miri/tests/fail/static_memory_modification1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: writing to ALLOC which is read-only
+  --> $DIR/static_memory_modification1.rs:LL:CC
+   |
+LL |         *std::mem::transmute::<&usize, &mut usize>(&X) = 6;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ writing to ALLOC which is read-only
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/static_memory_modification1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/static_memory_modification2.rs b/src/tools/miri/tests/fail/static_memory_modification2.rs
new file mode 100644
index 000000000000..d8ae3a57c51e
--- /dev/null
+++ b/src/tools/miri/tests/fail/static_memory_modification2.rs
@@ -0,0 +1,12 @@
+// Stacked Borrows detects that we are casting & to &mut and so it changes why we fail
+//@compile-flags: -Zmiri-disable-stacked-borrows
+
+use std::mem::transmute;
+
+#[allow(mutable_transmutes)]
+fn main() {
+    unsafe {
+        let s = "this is a test";
+        transmute::<&[u8], &mut [u8]>(s.as_bytes())[4] = 42; //~ ERROR: read-only
+    }
+}
diff --git a/src/tools/miri/tests/fail/static_memory_modification2.stderr b/src/tools/miri/tests/fail/static_memory_modification2.stderr
new file mode 100644
index 000000000000..4c160cd32068
--- /dev/null
+++ b/src/tools/miri/tests/fail/static_memory_modification2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: writing to ALLOC which is read-only
+  --> $DIR/static_memory_modification2.rs:LL:CC
+   |
+LL |         transmute::<&[u8], &mut [u8]>(s.as_bytes())[4] = 42;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ writing to ALLOC which is read-only
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/static_memory_modification2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/static_memory_modification3.rs b/src/tools/miri/tests/fail/static_memory_modification3.rs
new file mode 100644
index 000000000000..b8e2c6470ff2
--- /dev/null
+++ b/src/tools/miri/tests/fail/static_memory_modification3.rs
@@ -0,0 +1,12 @@
+// Stacked Borrows detects that we are casting & to &mut and so it changes why we fail
+//@compile-flags: -Zmiri-disable-stacked-borrows
+
+use std::mem::transmute;
+
+#[allow(mutable_transmutes)]
+fn main() {
+    unsafe {
+        let bs = b"this is a test";
+        transmute::<&[u8], &mut [u8]>(bs)[4] = 42; //~ ERROR: read-only
+    }
+}
diff --git a/src/tools/miri/tests/fail/static_memory_modification3.stderr b/src/tools/miri/tests/fail/static_memory_modification3.stderr
new file mode 100644
index 000000000000..1986059c50a8
--- /dev/null
+++ b/src/tools/miri/tests/fail/static_memory_modification3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: writing to ALLOC which is read-only
+  --> $DIR/static_memory_modification3.rs:LL:CC
+   |
+LL |         transmute::<&[u8], &mut [u8]>(bs)[4] = 42;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ writing to ALLOC which is read-only
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/static_memory_modification3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/transmute-pair-uninit.rs b/src/tools/miri/tests/fail/transmute-pair-uninit.rs
new file mode 100644
index 000000000000..bc95f3cb7ad3
--- /dev/null
+++ b/src/tools/miri/tests/fail/transmute-pair-uninit.rs
@@ -0,0 +1,24 @@
+#![feature(core_intrinsics)]
+
+use std::mem;
+
+fn main() {
+    let x: Option<Box<[u8]>> = unsafe {
+        let z = std::intrinsics::add_with_overflow(0usize, 0usize);
+        std::mem::transmute::<(usize, bool), Option<Box<[u8]>>>(z)
+    };
+    let y = &x;
+    // Now read this bytewise. There should be (`ptr_size + 1`) def bytes followed by
+    // (`ptr_size - 1`) undef bytes (the padding after the bool) in there.
+    let z: *const u8 = y as *const _ as *const _;
+    let first_undef = mem::size_of::<usize>() as isize + 1;
+    for i in 0..first_undef {
+        let byte = unsafe { *z.offset(i) };
+        assert_eq!(byte, 0);
+    }
+    let v = unsafe { *z.offset(first_undef) };
+    //~^ ERROR: uninitialized
+    if v == 0 {
+        println!("it is zero");
+    }
+}
diff --git a/src/tools/miri/tests/fail/transmute-pair-uninit.stderr b/src/tools/miri/tests/fail/transmute-pair-uninit.stderr
new file mode 100644
index 000000000000..642bf0a71343
--- /dev/null
+++ b/src/tools/miri/tests/fail/transmute-pair-uninit.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/transmute-pair-uninit.rs:LL:CC
+   |
+LL |     let v = unsafe { *z.offset(first_undef) };
+   |                      ^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/transmute-pair-uninit.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/type-too-large.rs b/src/tools/miri/tests/fail/type-too-large.rs
new file mode 100644
index 000000000000..21b272f8ec39
--- /dev/null
+++ b/src/tools/miri/tests/fail/type-too-large.rs
@@ -0,0 +1,6 @@
+//@ignore-32bit
+
+fn main() {
+    let _fat: [u8; (1 << 61) + (1 << 31)];
+    _fat = [0; (1u64 << 61) as usize + (1u64 << 31) as usize]; //~ ERROR: post-monomorphization error
+}
diff --git a/src/tools/miri/tests/fail/type-too-large.stderr b/src/tools/miri/tests/fail/type-too-large.stderr
new file mode 100644
index 000000000000..cb1d725ec878
--- /dev/null
+++ b/src/tools/miri/tests/fail/type-too-large.stderr
@@ -0,0 +1,12 @@
+error: post-monomorphization error: values of the type `[u8; 2305843011361177600]` are too big for the current architecture
+  --> $DIR/type-too-large.rs:LL:CC
+   |
+LL |     _fat = [0; (1u64 << 61) as usize + (1u64 << 31) as usize];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ values of the type `[u8; 2305843011361177600]` are too big for the current architecture
+   |
+   = note: inside `main` at $DIR/type-too-large.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/alignment.rs b/src/tools/miri/tests/fail/unaligned_pointers/alignment.rs
new file mode 100644
index 000000000000..438e74e5b8d5
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/alignment.rs
@@ -0,0 +1,14 @@
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+
+fn main() {
+    // No retry needed, this fails reliably.
+
+    let mut x = [0u8; 20];
+    let x_ptr: *mut u8 = x.as_mut_ptr();
+    #[rustfmt::skip]
+    unsafe {
+        // At least one of these is definitely unaligned.
+        *(x_ptr as *mut u32) = 42; *(x_ptr.add(1) as *mut u32) = 42;
+        //~^ ERROR: but alignment 4 is required
+    };
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/alignment.stderr b/src/tools/miri/tests/fail/unaligned_pointers/alignment.stderr
new file mode 100644
index 000000000000..bbebe3b89fd7
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/alignment.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/alignment.rs:LL:CC
+   |
+LL |         *(x_ptr as *mut u32) = 42; *(x_ptr.add(1) as *mut u32) = 42;
+   | ^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/alignment.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/atomic_unaligned.rs b/src/tools/miri/tests/fail/unaligned_pointers/atomic_unaligned.rs
new file mode 100644
index 000000000000..9dd652fd8217
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/atomic_unaligned.rs
@@ -0,0 +1,13 @@
+//@compile-flags: -Zmiri-symbolic-alignment-check
+#![feature(core_intrinsics)]
+
+fn main() {
+    // Do a 4-aligned u64 atomic access. That should be UB on all platforms,
+    // even if u64 only has alignment 4.
+    let z = [0u32; 2];
+    let zptr = &z as *const _ as *const u64;
+    unsafe {
+        ::std::intrinsics::atomic_load_seqcst(zptr);
+        //~^ERROR: accessing memory with alignment 4, but alignment 8 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/atomic_unaligned.stderr b/src/tools/miri/tests/fail/unaligned_pointers/atomic_unaligned.stderr
new file mode 100644
index 000000000000..8c3aa3429af5
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/atomic_unaligned.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/atomic_unaligned.rs:LL:CC
+   |
+LL |         ::std::intrinsics::atomic_load_seqcst(zptr);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this usually indicates that your program performed an invalid operation and caused Undefined Behavior
+   = help: but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/atomic_unaligned.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/dyn_alignment.rs b/src/tools/miri/tests/fail/unaligned_pointers/dyn_alignment.rs
new file mode 100644
index 000000000000..b943c7db7ccd
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/dyn_alignment.rs
@@ -0,0 +1,24 @@
+// should find the bug even without validation and stacked borrows, but gets masked by optimizations
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows -Zmir-opt-level=0
+
+#[repr(align(256))]
+#[derive(Debug)]
+struct MuchAlign;
+
+fn main() {
+    // Try many times as this might work by chance.
+    for _ in 0..10 {
+        let buf = [0u32; 256];
+        // `buf` is sufficiently aligned for `layout.align` on a `dyn Debug`, but not
+        // for the actual alignment required by `MuchAlign`.
+        // We craft a wide reference `&dyn Debug` with the vtable for `MuchAlign`. That should be UB,
+        // as the reference is not aligned to its dynamic alignment requirements.
+        let mut ptr = &MuchAlign as &dyn std::fmt::Debug;
+        // Overwrite the data part of `ptr` so it points to `buf`.
+        unsafe {
+            (&mut ptr as *mut _ as *mut *const u8).write(&buf as *const _ as *const u8);
+        }
+        // Re-borrow that. This should be UB.
+        let _ptr = &*ptr; //~ERROR: alignment 256 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/dyn_alignment.stderr b/src/tools/miri/tests/fail/unaligned_pointers/dyn_alignment.stderr
new file mode 100644
index 000000000000..a900b46612b8
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/dyn_alignment.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/dyn_alignment.rs:LL:CC
+   |
+LL |         let _ptr = &*ptr;
+   |                    ^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dyn_alignment.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.rs b/src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.rs
new file mode 100644
index 000000000000..da4cadc1c876
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.rs
@@ -0,0 +1,17 @@
+//@compile-flags: -Zmiri-symbolic-alignment-check -Zmiri-permissive-provenance
+// With the symbolic alignment check, even with intptrcast and without
+// validation, we want to be *sure* to catch bugs that arise from pointers being
+// insufficiently aligned. The only way to achieve that is not not let programs
+// exploit integer information for alignment, so here we test that this is
+// indeed the case.
+//
+// See https://github.com/rust-lang/miri/issues/1074.
+fn main() {
+    let x = &mut [0u8; 3];
+    let base_addr = x as *mut _ as usize;
+    // Manually make sure the pointer is properly aligned.
+    let base_addr_aligned = if base_addr % 2 == 0 { base_addr } else { base_addr + 1 };
+    let u16_ptr = base_addr_aligned as *mut u16;
+    unsafe { *u16_ptr = 2 }; //~ERROR: memory with alignment 1, but alignment 2 is required
+    println!("{:?}", x);
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.stderr b/src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.stderr
new file mode 100644
index 000000000000..392495a386de
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/intptrcast_alignment_check.rs:LL:CC
+   |
+LL |     unsafe { *u16_ptr = 2 };
+   |              ^^^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this usually indicates that your program performed an invalid operation and caused Undefined Behavior
+   = help: but due to `-Zmiri-symbolic-alignment-check`, alignment errors can also be false positives
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/intptrcast_alignment_check.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/reference_to_packed.rs b/src/tools/miri/tests/fail/unaligned_pointers/reference_to_packed.rs
new file mode 100644
index 000000000000..752210dca46e
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/reference_to_packed.rs
@@ -0,0 +1,19 @@
+// This should fail even without validation/SB
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+#![allow(dead_code, unused_variables, unaligned_references)]
+
+#[repr(packed)]
+struct Foo {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    // Try many times as this might work by chance.
+    for _ in 0..10 {
+        let foo = Foo { x: 42, y: 99 };
+        let p = &foo.x;
+        let i = *p; //~ERROR: alignment 4 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/reference_to_packed.stderr b/src/tools/miri/tests/fail/unaligned_pointers/reference_to_packed.stderr
new file mode 100644
index 000000000000..6c2a3dca2dee
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/reference_to_packed.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/reference_to_packed.rs:LL:CC
+   |
+LL |         let i = *p;
+   |                 ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/reference_to_packed.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr1.rs b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr1.rs
new file mode 100644
index 000000000000..73adc4dc4491
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr1.rs
@@ -0,0 +1,12 @@
+// This should fail even without validation or Stacked Borrows.
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+fn main() {
+    // Try many times as this might work by chance.
+    for _ in 0..10 {
+        let x = [2u16, 3, 4]; // Make it big enough so we don't get an out-of-bounds error.
+        let x = &x[0] as *const _ as *const u32;
+        // This must fail because alignment is violated: the allocation's base is not sufficiently aligned.
+        let _x = unsafe { *x }; //~ERROR: memory with alignment 2, but alignment 4 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr1.stderr b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr1.stderr
new file mode 100644
index 000000000000..49292be9cd15
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/unaligned_ptr1.rs:LL:CC
+   |
+LL |         let _x = unsafe { *x };
+   |                           ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unaligned_ptr1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr2.rs b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr2.rs
new file mode 100644
index 000000000000..c252944ffb7b
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr2.rs
@@ -0,0 +1,12 @@
+// This should fail even without validation or Stacked Borrows.
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+fn main() {
+    // No retry needed, this fails reliably.
+
+    let x = [2u32, 3]; // Make it big enough so we don't get an out-of-bounds error.
+    let x = (x.as_ptr() as *const u8).wrapping_offset(3) as *const u32;
+    // This must fail because alignment is violated: the offset is not sufficiently aligned.
+    // Also make the offset not a power of 2, that used to ICE.
+    let _x = unsafe { *x }; //~ERROR: memory with alignment 1, but alignment 4 is required
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr2.stderr b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr2.stderr
new file mode 100644
index 000000000000..e75482f723b6
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/unaligned_ptr2.rs:LL:CC
+   |
+LL |     let _x = unsafe { *x };
+   |                       ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unaligned_ptr2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr3.rs b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr3.rs
new file mode 100644
index 000000000000..7605dd175a98
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr3.rs
@@ -0,0 +1,13 @@
+// This should fail even without validation or Stacked Borrows.
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+fn main() {
+    // Try many times as this might work by chance.
+    for _ in 0..10 {
+        let x = [2u16, 3, 4, 5]; // Make it big enough so we don't get an out-of-bounds error.
+        let x = &x[0] as *const _ as *const *const u8; // cast to ptr-to-ptr, so that we load a ptr
+        // This must fail because alignment is violated. Test specifically for loading pointers,
+        // which have special code in miri's memory.
+        let _x = unsafe { *x }; //~ERROR: but alignment
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr3.stderr b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr3.stderr
new file mode 100644
index 000000000000..50dd4fdfc89f
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/unaligned_ptr3.rs:LL:CC
+   |
+LL |         let _x = unsafe { *x };
+   |                           ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unaligned_ptr3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr4.rs b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr4.rs
new file mode 100644
index 000000000000..852febe4c04c
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr4.rs
@@ -0,0 +1,14 @@
+// This should fail even without validation or Stacked Borrows.
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+
+fn main() {
+    // Make sure we notice when a u16 is loaded at offset 1 into a u8 allocation.
+    // (This would be missed if u8 allocations are *always* at odd addresses.)
+    //
+    // Try many times as this might work by chance.
+    for _ in 0..10 {
+        let x = [0u8; 4];
+        let ptr = x.as_ptr().wrapping_offset(1).cast::<u16>();
+        let _val = unsafe { *ptr }; //~ERROR: but alignment
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr4.stderr b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr4.stderr
new file mode 100644
index 000000000000..182f3e0f876f
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr4.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/unaligned_ptr4.rs:LL:CC
+   |
+LL |         let _val = unsafe { *ptr };
+   |                             ^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unaligned_ptr4.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_addr_of.rs b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_addr_of.rs
new file mode 100644
index 000000000000..e439cf2b03b9
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_addr_of.rs
@@ -0,0 +1,14 @@
+// This should fail even without validation or Stacked Borrows.
+//@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
+use std::ptr;
+
+fn main() {
+    // Try many times as this might work by chance.
+    for _ in 0..10 {
+        let x = [2u16, 3, 4]; // Make it big enough so we don't get an out-of-bounds error.
+        let x = &x[0] as *const _ as *const u32;
+        // This must fail because alignment is violated: the allocation's base is not sufficiently aligned.
+        // The deref is UB even if we just put the result into a raw pointer.
+        let _x = unsafe { ptr::addr_of!(*x) }; //~ ERROR: memory with alignment 2, but alignment 4 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_addr_of.stderr b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_addr_of.stderr
new file mode 100644
index 000000000000..2d8b1bf74508
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_addr_of.stderr
@@ -0,0 +1,16 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/unaligned_ptr_addr_of.rs:LL:CC
+   |
+LL |         let _x = unsafe { ptr::addr_of!(*x) };
+   |                           ^^^^^^^^^^^^^^^^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: this error originates in the macro `ptr::addr_of` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_zst.rs b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_zst.rs
new file mode 100644
index 000000000000..9076581b55bb
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_zst.rs
@@ -0,0 +1,13 @@
+// This should fail even without validation
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0 -Zmiri-disable-validation
+
+fn main() {
+    // Try many times as this might work by chance.
+    for i in 0..10 {
+        let x = i as u8;
+        let x = &x as *const _ as *const [u32; 0];
+        // This must fail because alignment is violated. Test specifically for loading ZST.
+        let _x = unsafe { *x }; //~ERROR: alignment 4 is required
+    }
+}
diff --git a/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_zst.stderr b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_zst.stderr
new file mode 100644
index 000000000000..aa0cbe1623b6
--- /dev/null
+++ b/src/tools/miri/tests/fail/unaligned_pointers/unaligned_ptr_zst.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: accessing memory with alignment ALIGN, but alignment ALIGN is required
+  --> $DIR/unaligned_ptr_zst.rs:LL:CC
+   |
+LL |         let _x = unsafe { *x };
+   |                           ^^ accessing memory with alignment ALIGN, but alignment ALIGN is required
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unaligned_ptr_zst.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/uninit_buffer.rs b/src/tools/miri/tests/fail/uninit_buffer.rs
new file mode 100644
index 000000000000..d21371225e57
--- /dev/null
+++ b/src/tools/miri/tests/fail/uninit_buffer.rs
@@ -0,0 +1,20 @@
+//@error-pattern: memory is uninitialized at [0x4..0x10]
+
+use std::alloc::{alloc, dealloc, Layout};
+use std::slice::from_raw_parts;
+
+fn main() {
+    let layout = Layout::from_size_align(32, 8).unwrap();
+    unsafe {
+        let ptr = alloc(layout);
+        *ptr = 0x41;
+        *ptr.add(1) = 0x42;
+        *ptr.add(2) = 0x43;
+        *ptr.add(3) = 0x44;
+        *ptr.add(16) = 0x00;
+        let slice1 = from_raw_parts(ptr, 16);
+        let slice2 = from_raw_parts(ptr.add(16), 16);
+        drop(slice1.cmp(slice2));
+        dealloc(ptr, layout);
+    }
+}
diff --git a/src/tools/miri/tests/fail/uninit_buffer.stderr b/src/tools/miri/tests/fail/uninit_buffer.stderr
new file mode 100644
index 000000000000..a543d59addb1
--- /dev/null
+++ b/src/tools/miri/tests/fail/uninit_buffer.stderr
@@ -0,0 +1,27 @@
+error: Undefined Behavior: reading memory at ALLOC[0x0..0x10], but memory is uninitialized at [0x4..0x10], and this operation requires initialized memory
+  --> RUSTLIB/core/src/slice/cmp.rs:LL:CC
+   |
+LL |         let mut order = unsafe { memcmp(left.as_ptr(), right.as_ptr(), len) as isize };
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ reading memory at ALLOC[0x0..0x10], but memory is uninitialized at [0x4..0x10], and this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `<u8 as core::slice::cmp::SliceOrd>::compare` at RUSTLIB/core/src/slice/cmp.rs:LL:CC
+   = note: inside `core::slice::cmp::<impl std::cmp::Ord for [u8]>::cmp` at RUSTLIB/core/src/slice/cmp.rs:LL:CC
+note: inside `main` at $DIR/uninit_buffer.rs:LL:CC
+  --> $DIR/uninit_buffer.rs:LL:CC
+   |
+LL |         drop(slice1.cmp(slice2));
+   |              ^^^^^^^^^^^^^^^^^^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+Uninitialized memory occurred at ALLOC[0x4..0x10], in this allocation:
+ALLOC (Rust heap, size: 32, align: 8) {
+    0x00 │ 41 42 43 44 __ __ __ __ __ __ __ __ __ __ __ __ │ ABCD░░░░░░░░░░░░
+    0x10 │ 00 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ .░░░░░░░░░░░░░░░
+}
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/uninit_byte_read.rs b/src/tools/miri/tests/fail/uninit_byte_read.rs
new file mode 100644
index 000000000000..f1dace0cff9b
--- /dev/null
+++ b/src/tools/miri/tests/fail/uninit_byte_read.rs
@@ -0,0 +1,7 @@
+//@compile-flags: -Zmiri-disable-stacked-borrows
+fn main() {
+    let v: Vec<u8> = Vec::with_capacity(10);
+    let undef = unsafe { *v.get_unchecked(5) }; //~ ERROR: uninitialized
+    let x = undef + 1;
+    panic!("this should never print: {}", x);
+}
diff --git a/src/tools/miri/tests/fail/uninit_byte_read.stderr b/src/tools/miri/tests/fail/uninit_byte_read.stderr
new file mode 100644
index 000000000000..9f7638888d64
--- /dev/null
+++ b/src/tools/miri/tests/fail/uninit_byte_read.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
+  --> $DIR/uninit_byte_read.rs:LL:CC
+   |
+LL |     let undef = unsafe { *v.get_unchecked(5) };
+   |                          ^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/uninit_byte_read.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unreachable.rs b/src/tools/miri/tests/fail/unreachable.rs
new file mode 100644
index 000000000000..3389d5b9ddea
--- /dev/null
+++ b/src/tools/miri/tests/fail/unreachable.rs
@@ -0,0 +1,3 @@
+fn main() {
+    unsafe { std::hint::unreachable_unchecked() } //~ERROR: entering unreachable code
+}
diff --git a/src/tools/miri/tests/fail/unreachable.stderr b/src/tools/miri/tests/fail/unreachable.stderr
new file mode 100644
index 000000000000..a57d731f1f71
--- /dev/null
+++ b/src/tools/miri/tests/fail/unreachable.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: entering unreachable code
+  --> $DIR/unreachable.rs:LL:CC
+   |
+LL |     unsafe { std::hint::unreachable_unchecked() }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ entering unreachable code
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unreachable.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unsized-local.rs b/src/tools/miri/tests/fail/unsized-local.rs
new file mode 100644
index 000000000000..ceccae4e3e76
--- /dev/null
+++ b/src/tools/miri/tests/fail/unsized-local.rs
@@ -0,0 +1,23 @@
+#![feature(unsized_locals)]
+#![allow(incomplete_features)]
+
+fn main() {
+    pub trait Foo {
+        fn foo(self) -> String;
+    }
+
+    struct A;
+
+    impl Foo for A {
+        fn foo(self) -> String {
+            format!("hello")
+        }
+    }
+
+    let x = *(Box::new(A) as Box<dyn Foo>); //~ERROR: unsized locals are not supported
+    assert_eq!(x.foo(), format!("hello"));
+
+    // I'm not sure whether we want this to work
+    let x = Box::new(A) as Box<dyn Foo>;
+    assert_eq!(x.foo(), format!("hello"));
+}
diff --git a/src/tools/miri/tests/fail/unsized-local.stderr b/src/tools/miri/tests/fail/unsized-local.stderr
new file mode 100644
index 000000000000..66d93c6f503c
--- /dev/null
+++ b/src/tools/miri/tests/fail/unsized-local.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: unsized locals are not supported
+  --> $DIR/unsized-local.rs:LL:CC
+   |
+LL |     let x = *(Box::new(A) as Box<dyn Foo>);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsized locals are not supported
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unsized-local.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unsupported_foreign_function.rs b/src/tools/miri/tests/fail/unsupported_foreign_function.rs
new file mode 100644
index 000000000000..dfd099e734b9
--- /dev/null
+++ b/src/tools/miri/tests/fail/unsupported_foreign_function.rs
@@ -0,0 +1,9 @@
+fn main() {
+    extern "Rust" {
+        fn foo();
+    }
+
+    unsafe {
+        foo(); //~ ERROR: unsupported operation: can't call foreign function: foo
+    }
+}
diff --git a/src/tools/miri/tests/fail/unsupported_foreign_function.stderr b/src/tools/miri/tests/fail/unsupported_foreign_function.stderr
new file mode 100644
index 000000000000..fde5fb78ac08
--- /dev/null
+++ b/src/tools/miri/tests/fail/unsupported_foreign_function.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: can't call foreign function: foo
+  --> $DIR/unsupported_foreign_function.rs:LL:CC
+   |
+LL |         foo();
+   |         ^^^^^ can't call foreign function: foo
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unsupported_foreign_function.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/unsupported_signal.rs b/src/tools/miri/tests/fail/unsupported_signal.rs
new file mode 100644
index 000000000000..d50041ffbd9d
--- /dev/null
+++ b/src/tools/miri/tests/fail/unsupported_signal.rs
@@ -0,0 +1,10 @@
+//! `signal()` is special on Linux and macOS that it's only supported within libstd.
+//! The implementation is not complete enough to permit user code to call it.
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    unsafe {
+        libc::signal(libc::SIGPIPE, libc::SIG_IGN);
+        //~^ ERROR: unsupported operation: can't call foreign function: signal
+    }
+}
diff --git a/src/tools/miri/tests/fail/unsupported_signal.stderr b/src/tools/miri/tests/fail/unsupported_signal.stderr
new file mode 100644
index 000000000000..d22ecbc11ff6
--- /dev/null
+++ b/src/tools/miri/tests/fail/unsupported_signal.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: can't call foreign function: signal
+  --> $DIR/unsupported_signal.rs:LL:CC
+   |
+LL |         libc::signal(libc::SIGPIPE, libc::SIG_IGN);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't call foreign function: signal
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/unsupported_signal.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/cast_fn_ptr1.rs b/src/tools/miri/tests/fail/validity/cast_fn_ptr1.rs
new file mode 100644
index 000000000000..6ab73569c634
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/cast_fn_ptr1.rs
@@ -0,0 +1,13 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    // Cast a function pointer such that on a call, the argument gets transmuted
+    // from raw ptr to reference. This is ABI-compatible, so it's not the call that
+    // should fail, but validation should.
+    fn f(_x: &i32) {}
+
+    let g: fn(*const i32) = unsafe { std::mem::transmute(f as fn(&i32)) };
+
+    g(0usize as *const i32)
+    //~^ ERROR: encountered a null reference
+}
diff --git a/src/tools/miri/tests/fail/validity/cast_fn_ptr1.stderr b/src/tools/miri/tests/fail/validity/cast_fn_ptr1.stderr
new file mode 100644
index 000000000000..133e4b2c16a1
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/cast_fn_ptr1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a null reference
+  --> $DIR/cast_fn_ptr1.rs:LL:CC
+   |
+LL |     g(0usize as *const i32)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null reference
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/cast_fn_ptr2.rs b/src/tools/miri/tests/fail/validity/cast_fn_ptr2.rs
new file mode 100644
index 000000000000..64ddb563be53
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/cast_fn_ptr2.rs
@@ -0,0 +1,15 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn main() {
+    // Cast a function pointer such that when returning, the return value gets transmuted
+    // from raw ptr to reference. This is ABI-compatible, so it's not the call that
+    // should fail, but validation should.
+    fn f() -> *const i32 {
+        0usize as *const i32
+    }
+
+    let g: fn() -> &'static i32 = unsafe { std::mem::transmute(f as fn() -> *const i32) };
+
+    let _x = g();
+    //~^ ERROR: encountered a null reference
+}
diff --git a/src/tools/miri/tests/fail/validity/cast_fn_ptr2.stderr b/src/tools/miri/tests/fail/validity/cast_fn_ptr2.stderr
new file mode 100644
index 000000000000..21001f2b4609
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/cast_fn_ptr2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a null reference
+  --> $DIR/cast_fn_ptr2.rs:LL:CC
+   |
+LL |     let _x = g();
+   |              ^^^ constructing invalid value: encountered a null reference
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/cast_fn_ptr2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/dangling_ref1.rs b/src/tools/miri/tests/fail/validity/dangling_ref1.rs
new file mode 100644
index 000000000000..6bf2d9295a37
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/dangling_ref1.rs
@@ -0,0 +1,7 @@
+// Make sure we catch this even without Stacked Borrows
+//@compile-flags: -Zmiri-disable-stacked-borrows
+use std::mem;
+
+fn main() {
+    let _x: &i32 = unsafe { mem::transmute(16usize) }; //~ ERROR: encountered a dangling reference (address 0x10 is unallocated)
+}
diff --git a/src/tools/miri/tests/fail/validity/dangling_ref1.stderr b/src/tools/miri/tests/fail/validity/dangling_ref1.stderr
new file mode 100644
index 000000000000..01ef071e8693
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/dangling_ref1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (address 0x10 is unallocated)
+  --> $DIR/dangling_ref1.rs:LL:CC
+   |
+LL |     let _x: &i32 = unsafe { mem::transmute(16usize) };
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (address 0x10 is unallocated)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_ref1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/dangling_ref2.rs b/src/tools/miri/tests/fail/validity/dangling_ref2.rs
new file mode 100644
index 000000000000..77d2358ae777
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/dangling_ref2.rs
@@ -0,0 +1,9 @@
+// Make sure we catch this even without Stacked Borrows
+//@compile-flags: -Zmiri-disable-stacked-borrows
+use std::mem;
+
+fn main() {
+    let val = 14;
+    let ptr = (&val as *const i32).wrapping_offset(1);
+    let _x: &i32 = unsafe { mem::transmute(ptr) }; //~ ERROR: dangling reference (going beyond the bounds of its allocation)
+}
diff --git a/src/tools/miri/tests/fail/validity/dangling_ref2.stderr b/src/tools/miri/tests/fail/validity/dangling_ref2.stderr
new file mode 100644
index 000000000000..4be4e8075a72
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/dangling_ref2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (going beyond the bounds of its allocation)
+  --> $DIR/dangling_ref2.rs:LL:CC
+   |
+LL |     let _x: &i32 = unsafe { mem::transmute(ptr) };
+   |                             ^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (going beyond the bounds of its allocation)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_ref2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/dangling_ref3.rs b/src/tools/miri/tests/fail/validity/dangling_ref3.rs
new file mode 100644
index 000000000000..8e8a75bd7ec0
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/dangling_ref3.rs
@@ -0,0 +1,12 @@
+// Make sure we catch this even without Stacked Borrows
+//@compile-flags: -Zmiri-disable-stacked-borrows
+use std::mem;
+
+fn dangling() -> *const u8 {
+    let x = 0u8;
+    &x as *const _
+}
+
+fn main() {
+    let _x: &i32 = unsafe { mem::transmute(dangling()) }; //~ ERROR: dangling reference (use-after-free)
+}
diff --git a/src/tools/miri/tests/fail/validity/dangling_ref3.stderr b/src/tools/miri/tests/fail/validity/dangling_ref3.stderr
new file mode 100644
index 000000000000..4b7bdf782368
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/dangling_ref3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (use-after-free)
+  --> $DIR/dangling_ref3.rs:LL:CC
+   |
+LL |     let _x: &i32 = unsafe { mem::transmute(dangling()) };
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (use-after-free)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/dangling_ref3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_bool.rs b/src/tools/miri/tests/fail/validity/invalid_bool.rs
new file mode 100644
index 000000000000..4f11bb2629f5
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_bool.rs
@@ -0,0 +1,3 @@
+fn main() {
+    let _b = unsafe { std::mem::transmute::<u8, bool>(2) }; //~ ERROR: expected a boolean
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_bool.stderr b/src/tools/miri/tests/fail/validity/invalid_bool.stderr
new file mode 100644
index 000000000000..3972787a4d2f
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_bool.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered 0x02, but expected a boolean
+  --> $DIR/invalid_bool.rs:LL:CC
+   |
+LL |     let _b = unsafe { std::mem::transmute::<u8, bool>(2) };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0x02, but expected a boolean
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_bool.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_bool_uninit.rs b/src/tools/miri/tests/fail/validity/invalid_bool_uninit.rs
new file mode 100644
index 000000000000..ce4fdcabd047
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_bool_uninit.rs
@@ -0,0 +1,10 @@
+#![allow(invalid_value)]
+
+union MyUninit {
+    init: (),
+    uninit: [bool; 1],
+}
+
+fn main() {
+    let _b = unsafe { MyUninit { init: () }.uninit }; //~ ERROR: constructing invalid value
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_bool_uninit.stderr b/src/tools/miri/tests/fail/validity/invalid_bool_uninit.stderr
new file mode 100644
index 000000000000..5a7bd80e40c1
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_bool_uninit.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at [0]: encountered uninitialized memory, but expected a boolean
+  --> $DIR/invalid_bool_uninit.rs:LL:CC
+   |
+LL |     let _b = unsafe { MyUninit { init: () }.uninit };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered uninitialized memory, but expected a boolean
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_bool_uninit.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_char.rs b/src/tools/miri/tests/fail/validity/invalid_char.rs
new file mode 100644
index 000000000000..568892e59109
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_char.rs
@@ -0,0 +1,9 @@
+fn main() {
+    assert!(std::char::from_u32(-1_i32 as u32).is_none());
+    let _val = match unsafe { std::mem::transmute::<i32, char>(-1) } {
+        //~^ ERROR: encountered 0xffffffff, but expected a valid unicode scalar value
+        'a' => true,
+        'b' => false,
+        _ => true,
+    };
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_char.stderr b/src/tools/miri/tests/fail/validity/invalid_char.stderr
new file mode 100644
index 000000000000..eeff289dfa4e
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_char.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
+  --> $DIR/invalid_char.rs:LL:CC
+   |
+LL |     let _val = match unsafe { std::mem::transmute::<i32, char>(-1) } {
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_char.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_char_uninit.rs b/src/tools/miri/tests/fail/validity/invalid_char_uninit.rs
new file mode 100644
index 000000000000..0e3c3ccac6f2
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_char_uninit.rs
@@ -0,0 +1,10 @@
+#![allow(invalid_value)]
+
+union MyUninit {
+    init: (),
+    uninit: [char; 1],
+}
+
+fn main() {
+    let _b = unsafe { MyUninit { init: () }.uninit }; //~ ERROR: constructing invalid value
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_char_uninit.stderr b/src/tools/miri/tests/fail/validity/invalid_char_uninit.stderr
new file mode 100644
index 000000000000..fb5d3ee1f1f9
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_char_uninit.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at [0]: encountered uninitialized memory, but expected a unicode scalar value
+  --> $DIR/invalid_char_uninit.rs:LL:CC
+   |
+LL |     let _b = unsafe { MyUninit { init: () }.uninit };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered uninitialized memory, but expected a unicode scalar value
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_char_uninit.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_enum_tag.rs b/src/tools/miri/tests/fail/validity/invalid_enum_tag.rs
new file mode 100644
index 000000000000..fa115e1e78e4
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_enum_tag.rs
@@ -0,0 +1,11 @@
+#[repr(C)]
+pub enum Foo {
+    A,
+    B,
+    C,
+    D,
+}
+
+fn main() {
+    let _f = unsafe { std::mem::transmute::<i32, Foo>(42) }; //~ ERROR: constructing invalid value at .<enum-tag>: encountered 0x0000002a, but expected a valid enum tag
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_enum_tag.stderr b/src/tools/miri/tests/fail/validity/invalid_enum_tag.stderr
new file mode 100644
index 000000000000..9234b4d705a9
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_enum_tag.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+  --> $DIR/invalid_enum_tag.rs:LL:CC
+   |
+LL |     let _f = unsafe { std::mem::transmute::<i32, Foo>(42) };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_enum_tag.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_fnptr_null.rs b/src/tools/miri/tests/fail/validity/invalid_fnptr_null.rs
new file mode 100644
index 000000000000..8d2045ca4a65
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_fnptr_null.rs
@@ -0,0 +1,5 @@
+#![allow(invalid_value)]
+
+fn main() {
+    let _b: fn() = unsafe { std::mem::transmute(0usize) }; //~ ERROR: encountered a null function pointer
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_fnptr_null.stderr b/src/tools/miri/tests/fail/validity/invalid_fnptr_null.stderr
new file mode 100644
index 000000000000..63fad1d56e38
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_fnptr_null.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a null function pointer
+  --> $DIR/invalid_fnptr_null.rs:LL:CC
+   |
+LL |     let _b: fn() = unsafe { std::mem::transmute(0usize) };
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null function pointer
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_fnptr_null.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_fnptr_uninit.rs b/src/tools/miri/tests/fail/validity/invalid_fnptr_uninit.rs
new file mode 100644
index 000000000000..014a8ae847a7
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_fnptr_uninit.rs
@@ -0,0 +1,10 @@
+#![allow(invalid_value)]
+
+union MyUninit {
+    init: (),
+    uninit: [fn(); 1],
+}
+
+fn main() {
+    let _b = unsafe { MyUninit { init: () }.uninit }; //~ ERROR: constructing invalid value
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_fnptr_uninit.stderr b/src/tools/miri/tests/fail/validity/invalid_fnptr_uninit.stderr
new file mode 100644
index 000000000000..35309e90136c
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_fnptr_uninit.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at [0]: encountered uninitialized memory, but expected a function pointer
+  --> $DIR/invalid_fnptr_uninit.rs:LL:CC
+   |
+LL |     let _b = unsafe { MyUninit { init: () }.uninit };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered uninitialized memory, but expected a function pointer
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_fnptr_uninit.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/invalid_wide_raw.rs b/src/tools/miri/tests/fail/validity/invalid_wide_raw.rs
new file mode 100644
index 000000000000..2ad972a9d4d7
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_wide_raw.rs
@@ -0,0 +1,11 @@
+#![allow(invalid_value)]
+
+fn main() {
+    trait T {}
+    #[derive(Debug)]
+    struct S {
+        #[allow(dead_code)]
+        x: *mut dyn T,
+    }
+    dbg!(S { x: unsafe { std::mem::transmute((0usize, 0usize)) } }); //~ ERROR: encountered null pointer, but expected a vtable pointer
+}
diff --git a/src/tools/miri/tests/fail/validity/invalid_wide_raw.stderr b/src/tools/miri/tests/fail/validity/invalid_wide_raw.stderr
new file mode 100644
index 000000000000..cf12ab8dbd55
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/invalid_wide_raw.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered null pointer, but expected a vtable pointer
+  --> $DIR/invalid_wide_raw.rs:LL:CC
+   |
+LL |     dbg!(S { x: unsafe { std::mem::transmute((0usize, 0usize)) } });
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a vtable pointer
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/invalid_wide_raw.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/nonzero.rs b/src/tools/miri/tests/fail/validity/nonzero.rs
new file mode 100644
index 000000000000..384c94a55699
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/nonzero.rs
@@ -0,0 +1,13 @@
+// gets masked by optimizations
+//@compile-flags: -Zmir-opt-level=0
+#![feature(rustc_attrs)]
+#![allow(unused_attributes)]
+
+#[rustc_layout_scalar_valid_range_start(1)]
+#[repr(transparent)]
+pub(crate) struct NonZero<T>(pub(crate) T);
+
+fn main() {
+    // Make sure that we detect this even when no function call is happening along the way
+    let _x = Some(unsafe { NonZero(0) }); //~ ERROR: encountered 0, but expected something greater or equal to 1
+}
diff --git a/src/tools/miri/tests/fail/validity/nonzero.stderr b/src/tools/miri/tests/fail/validity/nonzero.stderr
new file mode 100644
index 000000000000..a9a68177ed97
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/nonzero.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered 0, but expected something greater or equal to 1
+  --> $DIR/nonzero.rs:LL:CC
+   |
+LL |     let _x = Some(unsafe { NonZero(0) });
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0, but expected something greater or equal to 1
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/nonzero.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/ref_to_uninhabited1.rs b/src/tools/miri/tests/fail/validity/ref_to_uninhabited1.rs
new file mode 100644
index 000000000000..2e6be8b971c6
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/ref_to_uninhabited1.rs
@@ -0,0 +1,9 @@
+#![feature(never_type)]
+use std::mem::{forget, transmute};
+
+fn main() {
+    unsafe {
+        let x: Box<!> = transmute(&mut 42); //~ERROR: encountered a box pointing to uninhabited type !
+        forget(x);
+    }
+}
diff --git a/src/tools/miri/tests/fail/validity/ref_to_uninhabited1.stderr b/src/tools/miri/tests/fail/validity/ref_to_uninhabited1.stderr
new file mode 100644
index 000000000000..4facd2159c8d
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/ref_to_uninhabited1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a box pointing to uninhabited type !
+  --> $DIR/ref_to_uninhabited1.rs:LL:CC
+   |
+LL |         let x: Box<!> = transmute(&mut 42);
+   |                         ^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a box pointing to uninhabited type !
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ref_to_uninhabited1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/ref_to_uninhabited2.rs b/src/tools/miri/tests/fail/validity/ref_to_uninhabited2.rs
new file mode 100644
index 000000000000..8934a06b5d73
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/ref_to_uninhabited2.rs
@@ -0,0 +1,9 @@
+use std::mem::transmute;
+
+enum Void {}
+
+fn main() {
+    unsafe {
+        let _x: &(i32, Void) = transmute(&42); //~ERROR: encountered a reference pointing to uninhabited type (i32, Void)
+    }
+}
diff --git a/src/tools/miri/tests/fail/validity/ref_to_uninhabited2.stderr b/src/tools/miri/tests/fail/validity/ref_to_uninhabited2.stderr
new file mode 100644
index 000000000000..264465f93919
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/ref_to_uninhabited2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered a reference pointing to uninhabited type (i32, Void)
+  --> $DIR/ref_to_uninhabited2.rs:LL:CC
+   |
+LL |         let _x: &(i32, Void) = transmute(&42);
+   |                                ^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to uninhabited type (i32, Void)
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ref_to_uninhabited2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/too-big-slice.rs b/src/tools/miri/tests/fail/validity/too-big-slice.rs
new file mode 100644
index 000000000000..61d903220758
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/too-big-slice.rs
@@ -0,0 +1,8 @@
+use std::mem;
+
+fn main() {
+    unsafe {
+        let ptr = Box::into_raw(Box::new(0u8));
+        let _x: &[u8] = mem::transmute((ptr, usize::MAX)); //~ ERROR: invalid reference metadata: slice is bigger than largest supported object
+    }
+}
diff --git a/src/tools/miri/tests/fail/validity/too-big-slice.stderr b/src/tools/miri/tests/fail/validity/too-big-slice.stderr
new file mode 100644
index 000000000000..6df00aefe756
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/too-big-slice.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
+  --> $DIR/too-big-slice.rs:LL:CC
+   |
+LL |         let _x: &[u8] = mem::transmute((ptr, usize::MAX));
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/too-big-slice.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/too-big-unsized.rs b/src/tools/miri/tests/fail/validity/too-big-unsized.rs
new file mode 100644
index 000000000000..280205dccbf2
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/too-big-unsized.rs
@@ -0,0 +1,15 @@
+use std::mem;
+
+#[allow(unused)]
+struct MySlice {
+    prefix: u64,
+    tail: [u8],
+}
+
+fn main() {
+    unsafe {
+        let ptr = Box::into_raw(Box::new(0u8));
+        // The slice part is actually not "too big", but together with the `prefix` field it is.
+        let _x: &MySlice = mem::transmute((ptr, isize::MAX as usize)); //~ ERROR: invalid reference metadata: total size is bigger than largest supported object
+    }
+}
diff --git a/src/tools/miri/tests/fail/validity/too-big-unsized.stderr b/src/tools/miri/tests/fail/validity/too-big-unsized.stderr
new file mode 100644
index 000000000000..cbcb31b29fc3
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/too-big-unsized.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value: encountered invalid reference metadata: total size is bigger than largest supported object
+  --> $DIR/too-big-unsized.rs:LL:CC
+   |
+LL |         let _x: &MySlice = mem::transmute((ptr, isize::MAX as usize));
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: total size is bigger than largest supported object
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/too-big-unsized.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/transmute_through_ptr.rs b/src/tools/miri/tests/fail/validity/transmute_through_ptr.rs
new file mode 100644
index 000000000000..60b3bdd6cd69
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/transmute_through_ptr.rs
@@ -0,0 +1,19 @@
+#[repr(u32)]
+#[derive(Debug)]
+enum Bool {
+    True,
+}
+
+fn evil(x: &mut Bool) {
+    let x = x as *mut _ as *mut u32;
+    unsafe { *x = 44 }; // out-of-bounds enum tag
+}
+
+#[rustfmt::skip] // rustfmt bug: https://github.com/rust-lang/rustfmt/issues/5391
+fn main() {
+    let mut x = Bool::True;
+    evil(&mut x);
+    let y = x; // reading this ought to be enough to trigger validation
+    //~^ ERROR: constructing invalid value at .<enum-tag>: encountered 0x0000002c, but expected a valid enum tag
+    println!("{:?}", y); // make sure it is used (and not optimized away)
+}
diff --git a/src/tools/miri/tests/fail/validity/transmute_through_ptr.stderr b/src/tools/miri/tests/fail/validity/transmute_through_ptr.stderr
new file mode 100644
index 000000000000..ea155405cd61
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/transmute_through_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+  --> $DIR/transmute_through_ptr.rs:LL:CC
+   |
+LL |     let y = x; // reading this ought to be enough to trigger validation
+   |             ^ constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/transmute_through_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/uninit_float.rs b/src/tools/miri/tests/fail/validity/uninit_float.rs
new file mode 100644
index 000000000000..045bb46464fa
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/uninit_float.rs
@@ -0,0 +1,9 @@
+#![allow(deprecated, invalid_value)]
+// This test is adapted from https://github.com/rust-lang/miri/issues/1340#issue-600900312.
+
+fn main() {
+    // Deliberately using `mem::uninitialized` to make sure that despite all the mitigations, we consider this UB.
+    // The array avoids a `Scalar` layout which detects uninit without even doing validation.
+    let _val: [f32; 1] = unsafe { std::mem::uninitialized() };
+    //~^ ERROR: uninitialized
+}
diff --git a/src/tools/miri/tests/fail/validity/uninit_float.stderr b/src/tools/miri/tests/fail/validity/uninit_float.stderr
new file mode 100644
index 000000000000..677a0fc5570d
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/uninit_float.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized bytes
+  --> $DIR/uninit_float.rs:LL:CC
+   |
+LL |     let _val: [f32; 1] = unsafe { std::mem::uninitialized() };
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized bytes
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/uninit_float.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/uninit_integer.rs b/src/tools/miri/tests/fail/validity/uninit_integer.rs
new file mode 100644
index 000000000000..a94302603a21
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/uninit_integer.rs
@@ -0,0 +1,8 @@
+#![allow(invalid_value)]
+// This test is from https://github.com/rust-lang/miri/issues/1340#issue-600900312.
+
+fn main() {
+    // The array avoids a `Scalar` layout which detects uninit without even doing validation.
+    let _val = unsafe { std::mem::MaybeUninit::<[usize; 1]>::uninit().assume_init() };
+    //~^ ERROR: uninitialized
+}
diff --git a/src/tools/miri/tests/fail/validity/uninit_integer.stderr b/src/tools/miri/tests/fail/validity/uninit_integer.stderr
new file mode 100644
index 000000000000..a9ac2a6dc67e
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/uninit_integer.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized bytes
+  --> $DIR/uninit_integer.rs:LL:CC
+   |
+LL |     let _val = unsafe { std::mem::MaybeUninit::<[usize; 1]>::uninit().assume_init() };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized bytes
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/uninit_integer.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/validity/uninit_raw_ptr.rs b/src/tools/miri/tests/fail/validity/uninit_raw_ptr.rs
new file mode 100644
index 000000000000..18703152ea10
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/uninit_raw_ptr.rs
@@ -0,0 +1,7 @@
+#![allow(invalid_value)]
+
+fn main() {
+    // The array avoids a `Scalar` layout which detects uninit without even doing validation.
+    let _val = unsafe { std::mem::MaybeUninit::<[*const u8; 1]>::uninit().assume_init() };
+    //~^ ERROR: uninitialized
+}
diff --git a/src/tools/miri/tests/fail/validity/uninit_raw_ptr.stderr b/src/tools/miri/tests/fail/validity/uninit_raw_ptr.stderr
new file mode 100644
index 000000000000..bbae9cf69ffe
--- /dev/null
+++ b/src/tools/miri/tests/fail/validity/uninit_raw_ptr.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: constructing invalid value at .value[0]: encountered uninitialized memory, but expected a raw pointer
+  --> $DIR/uninit_raw_ptr.rs:LL:CC
+   |
+LL |     let _val = unsafe { std::mem::MaybeUninit::<[*const u8; 1]>::uninit().assume_init() };
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value[0]: encountered uninitialized memory, but expected a raw pointer
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/uninit_raw_ptr.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/weak_memory/racing_mixed_size.rs b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size.rs
new file mode 100644
index 000000000000..7bbb7f9fe7c2
--- /dev/null
+++ b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size.rs
@@ -0,0 +1,40 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+#![feature(core_intrinsics)]
+
+use std::ptr;
+use std::sync::atomic::AtomicU32;
+use std::sync::atomic::Ordering::*;
+use std::thread::spawn;
+
+fn static_atomic_u32(val: u32) -> &'static AtomicU32 {
+    let ret = Box::leak(Box::new(AtomicU32::new(val)));
+    ret
+}
+
+fn split_u32_ptr(dword: *const u32) -> *const [u16; 2] {
+    unsafe { std::mem::transmute::<*const u32, *const [u16; 2]>(dword) }
+}
+
+// Wine's SRWLock implementation does this, which is definitely undefined in C++ memory model
+// https://github.com/wine-mirror/wine/blob/303f8042f9db508adaca02ef21f8de4992cb9c03/dlls/ntdll/sync.c#L543-L566
+// Though it probably works just fine on x86
+pub fn main() {
+    let x = static_atomic_u32(0);
+    let j1 = spawn(move || {
+        x.store(1, Relaxed);
+    });
+
+    let j2 = spawn(move || {
+        let x_ptr = x as *const AtomicU32 as *const u32;
+        let x_split = split_u32_ptr(x_ptr);
+        unsafe {
+            let hi = ptr::addr_of!((*x_split)[0]);
+            std::intrinsics::atomic_load_relaxed(hi); //~ ERROR: imperfectly overlapping
+        }
+    });
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+}
diff --git a/src/tools/miri/tests/fail/weak_memory/racing_mixed_size.stderr b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size.stderr
new file mode 100644
index 000000000000..dda22ac9ce24
--- /dev/null
+++ b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation
+  --> $DIR/racing_mixed_size.rs:LL:CC
+   |
+LL |             std::intrinsics::atomic_load_relaxed(hi);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/racing_mixed_size.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/weak_memory/racing_mixed_size_read.rs b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size_read.rs
new file mode 100644
index 000000000000..73178980b7e5
--- /dev/null
+++ b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size_read.rs
@@ -0,0 +1,38 @@
+// We want to control preemption here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::sync::atomic::Ordering::*;
+use std::sync::atomic::{AtomicU16, AtomicU32};
+use std::thread::spawn;
+
+fn static_atomic(val: u32) -> &'static AtomicU32 {
+    let ret = Box::leak(Box::new(AtomicU32::new(val)));
+    ret
+}
+
+fn split_u32_ptr(dword: *const u32) -> *const [u16; 2] {
+    unsafe { std::mem::transmute::<*const u32, *const [u16; 2]>(dword) }
+}
+
+// Racing mixed size reads may cause two loads to read-from
+// the same store but observe different values, which doesn't make
+// sense under the formal model so we forbade this.
+pub fn main() {
+    let x = static_atomic(0);
+
+    let j1 = spawn(move || {
+        x.load(Relaxed);
+    });
+
+    let j2 = spawn(move || {
+        let x_ptr = x as *const AtomicU32 as *const u32;
+        let x_split = split_u32_ptr(x_ptr);
+        unsafe {
+            let hi = x_split as *const u16 as *const AtomicU16;
+            (*hi).load(Relaxed); //~ ERROR: imperfectly overlapping
+        }
+    });
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+}
diff --git a/src/tools/miri/tests/fail/weak_memory/racing_mixed_size_read.stderr b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size_read.stderr
new file mode 100644
index 000000000000..59fa5c741023
--- /dev/null
+++ b/src/tools/miri/tests/fail/weak_memory/racing_mixed_size_read.stderr
@@ -0,0 +1,14 @@
+error: unsupported operation: racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation
+  --> $DIR/racing_mixed_size_read.rs:LL:CC
+   |
+LL |             (*hi).load(Relaxed);
+   |             ^^^^^^^^^^^^^^^^^^^ racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+   = note: BACKTRACE:
+   = note: inside closure at $DIR/racing_mixed_size_read.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/zst1.rs b/src/tools/miri/tests/fail/zst1.rs
new file mode 100644
index 000000000000..cc81481e4fa4
--- /dev/null
+++ b/src/tools/miri/tests/fail/zst1.rs
@@ -0,0 +1,5 @@
+fn main() {
+    // make sure ZST locals cannot be accessed
+    let x = &() as *const () as *const i8;
+    let _val = unsafe { *x }; //~ ERROR: out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/zst1.stderr b/src/tools/miri/tests/fail/zst1.stderr
new file mode 100644
index 000000000000..b89f06af9589
--- /dev/null
+++ b/src/tools/miri/tests/fail/zst1.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 0, so pointer to 1 byte starting at offset 0 is out-of-bounds
+  --> $DIR/zst1.rs:LL:CC
+   |
+LL |     let _val = unsafe { *x };
+   |                         ^^ dereferencing pointer failed: ALLOC has size 0, so pointer to 1 byte starting at offset 0 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/zst1.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/zst2.rs b/src/tools/miri/tests/fail/zst2.rs
new file mode 100644
index 000000000000..82470866f179
--- /dev/null
+++ b/src/tools/miri/tests/fail/zst2.rs
@@ -0,0 +1,15 @@
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0
+
+fn main() {
+    // Not using the () type here, as writes of that type do not even have MIR generated.
+    // Also not assigning directly as that's array initialization, not assignment.
+    let zst_val = [1u8; 0];
+
+    // make sure ZST accesses are checked against being "truly" dangling pointers
+    // (into deallocated allocations).
+    let mut x_box = Box::new(1u8);
+    let x = &mut *x_box as *mut _ as *mut [u8; 0];
+    drop(x_box);
+    unsafe { *x = zst_val }; //~ ERROR: dereferenced after this allocation got freed
+}
diff --git a/src/tools/miri/tests/fail/zst2.stderr b/src/tools/miri/tests/fail/zst2.stderr
new file mode 100644
index 000000000000..6c49656e4c67
--- /dev/null
+++ b/src/tools/miri/tests/fail/zst2.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: pointer to ALLOC was dereferenced after this allocation got freed
+  --> $DIR/zst2.rs:LL:CC
+   |
+LL |     unsafe { *x = zst_val };
+   |              ^^^^^^^^^^^^ pointer to ALLOC was dereferenced after this allocation got freed
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/zst2.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/fail/zst3.rs b/src/tools/miri/tests/fail/zst3.rs
new file mode 100644
index 000000000000..a511f38998fe
--- /dev/null
+++ b/src/tools/miri/tests/fail/zst3.rs
@@ -0,0 +1,18 @@
+// Some optimizations remove ZST accesses, thus masking this UB.
+//@compile-flags: -Zmir-opt-level=0
+
+fn main() {
+    // Not using the () type here, as writes of that type do not even have MIR generated.
+    // Also not assigning directly as that's array initialization, not assignment.
+    let zst_val = [1u8; 0];
+
+    // make sure ZST accesses are checked against being "truly" dangling pointers
+    // (that are out-of-bounds).
+    let mut x_box = Box::new(1u8);
+    let x = (&mut *x_box as *mut u8).wrapping_offset(1);
+    // This one is just "at the edge", but still okay
+    unsafe { *(x as *mut [u8; 0]) = zst_val };
+    // One byte further is OOB.
+    let x = x.wrapping_offset(1);
+    unsafe { *(x as *mut [u8; 0]) = zst_val }; //~ ERROR: out-of-bounds
+}
diff --git a/src/tools/miri/tests/fail/zst3.stderr b/src/tools/miri/tests/fail/zst3.stderr
new file mode 100644
index 000000000000..c9accf2c8fbe
--- /dev/null
+++ b/src/tools/miri/tests/fail/zst3.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: dereferencing pointer failed: ALLOC has size 1, so pointer at offset 2 is out-of-bounds
+  --> $DIR/zst3.rs:LL:CC
+   |
+LL |     unsafe { *(x as *mut [u8; 0]) = zst_val };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: ALLOC has size 1, so pointer at offset 2 is out-of-bounds
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/zst3.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+
diff --git a/src/tools/miri/tests/panic/div-by-zero-2.rs b/src/tools/miri/tests/panic/div-by-zero-2.rs
new file mode 100644
index 000000000000..fac5415696fc
--- /dev/null
+++ b/src/tools/miri/tests/panic/div-by-zero-2.rs
@@ -0,0 +1,5 @@
+#![allow(unconditional_panic)]
+
+fn main() {
+    let _n = 1 / 0;
+}
diff --git a/src/tools/miri/tests/panic/div-by-zero-2.stderr b/src/tools/miri/tests/panic/div-by-zero-2.stderr
new file mode 100644
index 000000000000..538d87113654
--- /dev/null
+++ b/src/tools/miri/tests/panic/div-by-zero-2.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'attempt to divide by zero', $DIR/div-by-zero-2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.rs b/src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.rs
new file mode 100644
index 000000000000..71b799a1f12b
--- /dev/null
+++ b/src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.rs
@@ -0,0 +1,38 @@
+// Make sure the workaround for "crate ... required to be available in rlib format, but was not
+// found in this form" errors works without `-C prefer-dynamic` (`panic!` calls foreign function
+// `__rust_start_panic`).
+// no-prefer-dynamic
+#![feature(c_unwind, unboxed_closures)]
+
+use std::panic;
+
+#[no_mangle]
+extern "C-unwind" fn good_unwind_c() {
+    panic!();
+}
+
+#[no_mangle]
+fn good_unwind_rust() {
+    panic!();
+}
+
+// Diverging function calls are on a different code path.
+#[no_mangle]
+extern "rust-call" fn good_unwind_rust_call(_: ()) -> ! {
+    panic!();
+}
+
+fn main() -> ! {
+    extern "C-unwind" {
+        fn good_unwind_c();
+    }
+    panic::catch_unwind(|| unsafe { good_unwind_c() }).unwrap_err();
+    extern "Rust" {
+        fn good_unwind_rust();
+    }
+    panic::catch_unwind(|| unsafe { good_unwind_rust() }).unwrap_err();
+    extern "rust-call" {
+        fn good_unwind_rust_call(_: ()) -> !;
+    }
+    unsafe { good_unwind_rust_call(()) }
+}
diff --git a/src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.stderr b/src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.stderr
new file mode 100644
index 000000000000..bff897775e8f
--- /dev/null
+++ b/src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.stderr
@@ -0,0 +1,4 @@
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
+thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
diff --git a/src/tools/miri/tests/panic/overflowing-lsh-neg.rs b/src/tools/miri/tests/panic/overflowing-lsh-neg.rs
new file mode 100644
index 000000000000..bf5eed1c550f
--- /dev/null
+++ b/src/tools/miri/tests/panic/overflowing-lsh-neg.rs
@@ -0,0 +1,5 @@
+#![allow(arithmetic_overflow)]
+
+fn main() {
+    let _n = 2i64 << -1;
+}
diff --git a/src/tools/miri/tests/panic/overflowing-lsh-neg.stderr b/src/tools/miri/tests/panic/overflowing-lsh-neg.stderr
new file mode 100644
index 000000000000..21e434d873f7
--- /dev/null
+++ b/src/tools/miri/tests/panic/overflowing-lsh-neg.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'attempt to shift left with overflow', $DIR/overflowing-lsh-neg.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/overflowing-rsh-1.rs b/src/tools/miri/tests/panic/overflowing-rsh-1.rs
new file mode 100644
index 000000000000..4c0106f0fb1f
--- /dev/null
+++ b/src/tools/miri/tests/panic/overflowing-rsh-1.rs
@@ -0,0 +1,5 @@
+#![allow(arithmetic_overflow)]
+
+fn main() {
+    let _n = 1i64 >> 64;
+}
diff --git a/src/tools/miri/tests/panic/overflowing-rsh-1.stderr b/src/tools/miri/tests/panic/overflowing-rsh-1.stderr
new file mode 100644
index 000000000000..fd04bf1bd4ec
--- /dev/null
+++ b/src/tools/miri/tests/panic/overflowing-rsh-1.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'attempt to shift right with overflow', $DIR/overflowing-rsh-1.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/overflowing-rsh-2.rs b/src/tools/miri/tests/panic/overflowing-rsh-2.rs
new file mode 100644
index 000000000000..19d16e7bc84a
--- /dev/null
+++ b/src/tools/miri/tests/panic/overflowing-rsh-2.rs
@@ -0,0 +1,6 @@
+#![allow(arithmetic_overflow)]
+
+fn main() {
+    // Make sure we catch overflows that would be hidden by first casting the RHS to u32
+    let _n = 1i64 >> (u32::MAX as i64 + 1);
+}
diff --git a/src/tools/miri/tests/panic/overflowing-rsh-2.stderr b/src/tools/miri/tests/panic/overflowing-rsh-2.stderr
new file mode 100644
index 000000000000..eb568e4d742b
--- /dev/null
+++ b/src/tools/miri/tests/panic/overflowing-rsh-2.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'attempt to shift right with overflow', $DIR/overflowing-rsh-2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/panic1.rs b/src/tools/miri/tests/panic/panic1.rs
new file mode 100644
index 000000000000..dbddf41fdbf7
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic1.rs
@@ -0,0 +1,6 @@
+//@rustc-env: RUST_BACKTRACE=1
+//@compile-flags: -Zmiri-disable-isolation
+
+fn main() {
+    std::panic!("panicking from libstd");
+}
diff --git a/src/tools/miri/tests/panic/panic1.stderr b/src/tools/miri/tests/panic/panic1.stderr
new file mode 100644
index 000000000000..15834d58bc6e
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic1.stderr
@@ -0,0 +1,9 @@
+thread 'main' panicked at 'panicking from libstd', $DIR/panic1.rs:LL:CC
+stack backtrace:
+   0: std::rt::begin_panic
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+   1: main
+ at $DIR/panic1.rs:LL:CC
+   2: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
diff --git a/src/tools/miri/tests/panic/panic2.rs b/src/tools/miri/tests/panic/panic2.rs
new file mode 100644
index 000000000000..d90e3f2e0ac1
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic2.rs
@@ -0,0 +1,3 @@
+fn main() {
+    std::panic!("{}-panicking from libstd", 42);
+}
diff --git a/src/tools/miri/tests/panic/panic2.stderr b/src/tools/miri/tests/panic/panic2.stderr
new file mode 100644
index 000000000000..c192ca3f64c3
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic2.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at '42-panicking from libstd', $DIR/panic2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/panic3.rs b/src/tools/miri/tests/panic/panic3.rs
new file mode 100644
index 000000000000..418ee4f8411e
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic3.rs
@@ -0,0 +1,3 @@
+fn main() {
+    core::panic!("panicking from libcore");
+}
diff --git a/src/tools/miri/tests/panic/panic3.stderr b/src/tools/miri/tests/panic/panic3.stderr
new file mode 100644
index 000000000000..0ce4a37fd519
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic3.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'panicking from libcore', $DIR/panic3.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/panic4.rs b/src/tools/miri/tests/panic/panic4.rs
new file mode 100644
index 000000000000..0fcc53813b5d
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic4.rs
@@ -0,0 +1,3 @@
+fn main() {
+    core::panic!("{}-panicking from libcore", 42);
+}
diff --git a/src/tools/miri/tests/panic/panic4.stderr b/src/tools/miri/tests/panic/panic4.stderr
new file mode 100644
index 000000000000..82df953b61c0
--- /dev/null
+++ b/src/tools/miri/tests/panic/panic4.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at '42-panicking from libcore', $DIR/panic4.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/transmute_fat2.rs b/src/tools/miri/tests/panic/transmute_fat2.rs
new file mode 100644
index 000000000000..0205433ad9fb
--- /dev/null
+++ b/src/tools/miri/tests/panic/transmute_fat2.rs
@@ -0,0 +1,10 @@
+fn main() {
+    #[cfg(all(target_endian = "little", target_pointer_width = "64"))]
+    let bad = unsafe { std::mem::transmute::<u128, &[u8]>(42) };
+    #[cfg(all(target_endian = "big", target_pointer_width = "64"))]
+    let bad = unsafe { std::mem::transmute::<u128, &[u8]>(42 << 64) };
+    #[cfg(all(target_endian = "little", target_pointer_width = "32"))]
+    let bad = unsafe { std::mem::transmute::<u64, &[u8]>(42) };
+    // This created a slice with length 0, so the following will fail the bounds check.
+    bad[0];
+}
diff --git a/src/tools/miri/tests/panic/transmute_fat2.stderr b/src/tools/miri/tests/panic/transmute_fat2.stderr
new file mode 100644
index 000000000000..f497ab672550
--- /dev/null
+++ b/src/tools/miri/tests/panic/transmute_fat2.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', $DIR/transmute_fat2.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/unsupported_foreign_function.rs b/src/tools/miri/tests/panic/unsupported_foreign_function.rs
new file mode 100644
index 000000000000..a78646528fb1
--- /dev/null
+++ b/src/tools/miri/tests/panic/unsupported_foreign_function.rs
@@ -0,0 +1,11 @@
+//@compile-flags: -Zmiri-panic-on-unsupported
+
+fn main() {
+    extern "Rust" {
+        fn foo();
+    }
+
+    unsafe {
+        foo();
+    }
+}
diff --git a/src/tools/miri/tests/panic/unsupported_foreign_function.stderr b/src/tools/miri/tests/panic/unsupported_foreign_function.stderr
new file mode 100644
index 000000000000..9af3e48655f3
--- /dev/null
+++ b/src/tools/miri/tests/panic/unsupported_foreign_function.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'unsupported Miri functionality: can't call foreign function: foo', $DIR/unsupported_foreign_function.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/panic/unsupported_syscall.rs b/src/tools/miri/tests/panic/unsupported_syscall.rs
new file mode 100644
index 000000000000..31d666e1d9d8
--- /dev/null
+++ b/src/tools/miri/tests/panic/unsupported_syscall.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: No libc on Windows
+//@ignore-target-apple: `syscall` is not supported on macOS
+//@compile-flags: -Zmiri-panic-on-unsupported
+
+fn main() {
+    unsafe {
+        libc::syscall(0);
+    }
+}
diff --git a/src/tools/miri/tests/panic/unsupported_syscall.stderr b/src/tools/miri/tests/panic/unsupported_syscall.stderr
new file mode 100644
index 000000000000..90aa5a907363
--- /dev/null
+++ b/src/tools/miri/tests/panic/unsupported_syscall.stderr
@@ -0,0 +1,2 @@
+thread 'main' panicked at 'unsupported Miri functionality: can't execute syscall with ID 0', $DIR/unsupported_syscall.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
diff --git a/src/tools/miri/tests/pass-dep/calloc.rs b/src/tools/miri/tests/pass-dep/calloc.rs
new file mode 100644
index 000000000000..62ab63c5fc78
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/calloc.rs
@@ -0,0 +1,22 @@
+//@ignore-target-windows: No libc on Windows
+
+use core::slice;
+
+fn main() {
+    unsafe {
+        let p1 = libc::calloc(0, 0);
+        assert!(p1.is_null());
+
+        let p2 = libc::calloc(20, 0);
+        assert!(p2.is_null());
+
+        let p3 = libc::calloc(0, 20);
+        assert!(p3.is_null());
+
+        let p4 = libc::calloc(4, 8);
+        assert!(!p4.is_null());
+        let slice = slice::from_raw_parts(p4 as *const u8, 4 * 8);
+        assert_eq!(&slice, &[0_u8; 4 * 8]);
+        libc::free(p4);
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/concurrency/libc_pthread_cond.rs b/src/tools/miri/tests/pass-dep/concurrency/libc_pthread_cond.rs
new file mode 100644
index 000000000000..b0325f7d78e5
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/concurrency/libc_pthread_cond.rs
@@ -0,0 +1,84 @@
+//@ignore-target-windows: No libc on Windows
+//@ignore-target-apple: pthread_condattr_setclock is not supported on MacOS.
+//@compile-flags: -Zmiri-disable-isolation
+
+/// Test that conditional variable timeouts are working properly with both
+/// monotonic and system clocks.
+use std::mem::MaybeUninit;
+use std::time::Instant;
+
+fn test_timed_wait_timeout(clock_id: i32) {
+    unsafe {
+        let mut attr: MaybeUninit<libc::pthread_condattr_t> = MaybeUninit::uninit();
+        assert_eq!(libc::pthread_condattr_init(attr.as_mut_ptr()), 0);
+        assert_eq!(libc::pthread_condattr_setclock(attr.as_mut_ptr(), clock_id), 0);
+
+        let mut cond: MaybeUninit<libc::pthread_cond_t> = MaybeUninit::uninit();
+        assert_eq!(libc::pthread_cond_init(cond.as_mut_ptr(), attr.as_ptr()), 0);
+        assert_eq!(libc::pthread_condattr_destroy(attr.as_mut_ptr()), 0);
+
+        let mut mutex: libc::pthread_mutex_t = libc::PTHREAD_MUTEX_INITIALIZER;
+
+        let mut now_mu: MaybeUninit<libc::timespec> = MaybeUninit::uninit();
+        assert_eq!(libc::clock_gettime(clock_id, now_mu.as_mut_ptr()), 0);
+        let now = now_mu.assume_init();
+        // Waiting for a second... mostly because waiting less requires mich more tricky arithmetic.
+        // FIXME: wait less.
+        let timeout = libc::timespec { tv_sec: now.tv_sec + 1, tv_nsec: now.tv_nsec };
+
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        let current_time = Instant::now();
+        assert_eq!(
+            libc::pthread_cond_timedwait(cond.as_mut_ptr(), &mut mutex as *mut _, &timeout),
+            libc::ETIMEDOUT
+        );
+        let elapsed_time = current_time.elapsed().as_millis();
+        assert!(900 <= elapsed_time && elapsed_time <= 1300);
+
+        // Test calling `pthread_cond_timedwait` again with an already elapsed timeout.
+        assert_eq!(
+            libc::pthread_cond_timedwait(cond.as_mut_ptr(), &mut mutex as *mut _, &timeout),
+            libc::ETIMEDOUT
+        );
+
+        // Test that invalid nanosecond values (above 10^9 or negative) are rejected with the
+        // correct error code.
+        let invalid_timeout_1 = libc::timespec { tv_sec: now.tv_sec + 1, tv_nsec: 1_000_000_000 };
+        assert_eq!(
+            libc::pthread_cond_timedwait(
+                cond.as_mut_ptr(),
+                &mut mutex as *mut _,
+                &invalid_timeout_1
+            ),
+            libc::EINVAL
+        );
+        let invalid_timeout_2 = libc::timespec { tv_sec: now.tv_sec + 1, tv_nsec: -1 };
+        assert_eq!(
+            libc::pthread_cond_timedwait(
+                cond.as_mut_ptr(),
+                &mut mutex as *mut _,
+                &invalid_timeout_2
+            ),
+            libc::EINVAL
+        );
+        // Test that invalid second values (negative) are rejected with the correct error code.
+        let invalid_timeout_3 = libc::timespec { tv_sec: -1, tv_nsec: 0 };
+        assert_eq!(
+            libc::pthread_cond_timedwait(
+                cond.as_mut_ptr(),
+                &mut mutex as *mut _,
+                &invalid_timeout_3
+            ),
+            libc::EINVAL
+        );
+
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_destroy(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_cond_destroy(cond.as_mut_ptr()), 0);
+    }
+}
+
+fn main() {
+    test_timed_wait_timeout(libc::CLOCK_MONOTONIC);
+    test_timed_wait_timeout(libc::CLOCK_REALTIME);
+}
diff --git a/src/tools/miri/tests/pass-dep/concurrency/linux-futex.rs b/src/tools/miri/tests/pass-dep/concurrency/linux-futex.rs
new file mode 100644
index 000000000000..a456528ec207
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/concurrency/linux-futex.rs
@@ -0,0 +1,291 @@
+//@only-target-linux
+//@compile-flags: -Zmiri-disable-isolation
+
+use std::mem::MaybeUninit;
+use std::ptr;
+use std::sync::atomic::AtomicI32;
+use std::sync::atomic::Ordering;
+use std::thread;
+use std::time::{Duration, Instant};
+
+fn wake_nobody() {
+    let futex = 0;
+
+    // Wake 1 waiter. Expect zero waiters woken up, as nobody is waiting.
+    unsafe {
+        assert_eq!(libc::syscall(libc::SYS_futex, &futex as *const i32, libc::FUTEX_WAKE, 1), 0);
+    }
+
+    // Same, but without omitting the unused arguments.
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_futex,
+                &futex as *const i32,
+                libc::FUTEX_WAKE,
+                1,
+                ptr::null::<libc::timespec>(),
+                0usize,
+                0,
+            ),
+            0,
+        );
+    }
+}
+
+fn wake_dangling() {
+    let futex = Box::new(0);
+    let ptr: *const i32 = &*futex;
+    drop(futex);
+
+    // Wake 1 waiter. Expect zero waiters woken up, as nobody is waiting.
+    unsafe {
+        assert_eq!(libc::syscall(libc::SYS_futex, ptr, libc::FUTEX_WAKE, 1), 0);
+    }
+}
+
+fn wait_wrong_val() {
+    let futex: i32 = 123;
+
+    // Only wait if the futex value is 456.
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_futex,
+                &futex as *const i32,
+                libc::FUTEX_WAIT,
+                456,
+                ptr::null::<libc::timespec>(),
+            ),
+            -1,
+        );
+        assert_eq!(*libc::__errno_location(), libc::EAGAIN);
+    }
+}
+
+fn wait_timeout() {
+    let start = Instant::now();
+
+    let futex: i32 = 123;
+
+    // Wait for 200ms, with nobody waking us up early.
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_futex,
+                &futex as *const i32,
+                libc::FUTEX_WAIT,
+                123,
+                &libc::timespec { tv_sec: 0, tv_nsec: 200_000_000 },
+            ),
+            -1,
+        );
+        assert_eq!(*libc::__errno_location(), libc::ETIMEDOUT);
+    }
+
+    assert!((200..1000).contains(&start.elapsed().as_millis()));
+}
+
+fn wait_absolute_timeout() {
+    let start = Instant::now();
+
+    // Get the current monotonic timestamp as timespec.
+    let mut timeout = unsafe {
+        let mut now: MaybeUninit<libc::timespec> = MaybeUninit::uninit();
+        assert_eq!(libc::clock_gettime(libc::CLOCK_MONOTONIC, now.as_mut_ptr()), 0);
+        now.assume_init()
+    };
+
+    // Add 200ms.
+    timeout.tv_nsec += 200_000_000;
+    if timeout.tv_nsec > 1_000_000_000 {
+        timeout.tv_nsec -= 1_000_000_000;
+        timeout.tv_sec += 1;
+    }
+
+    let futex: i32 = 123;
+
+    // Wait for 200ms from now, with nobody waking us up early.
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_futex,
+                &futex as *const i32,
+                libc::FUTEX_WAIT_BITSET,
+                123,
+                &timeout,
+                0usize,
+                u32::MAX,
+            ),
+            -1,
+        );
+        assert_eq!(*libc::__errno_location(), libc::ETIMEDOUT);
+    }
+
+    assert!((200..1000).contains(&start.elapsed().as_millis()));
+}
+
+fn wait_wake() {
+    let start = Instant::now();
+
+    static mut FUTEX: i32 = 0;
+
+    let t = thread::spawn(move || {
+        thread::sleep(Duration::from_millis(200));
+        unsafe {
+            assert_eq!(
+                libc::syscall(
+                    libc::SYS_futex,
+                    &FUTEX as *const i32,
+                    libc::FUTEX_WAKE,
+                    10, // Wake up at most 10 threads.
+                ),
+                1, // Woken up one thread.
+            );
+        }
+    });
+
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_futex,
+                &FUTEX as *const i32,
+                libc::FUTEX_WAIT,
+                0,
+                ptr::null::<libc::timespec>(),
+            ),
+            0,
+        );
+    }
+
+    assert!((200..1000).contains(&start.elapsed().as_millis()));
+    t.join().unwrap();
+}
+
+fn wait_wake_bitset() {
+    let start = Instant::now();
+
+    static mut FUTEX: i32 = 0;
+
+    let t = thread::spawn(move || {
+        thread::sleep(Duration::from_millis(200));
+        unsafe {
+            assert_eq!(
+                libc::syscall(
+                    libc::SYS_futex,
+                    &FUTEX as *const i32,
+                    libc::FUTEX_WAKE_BITSET,
+                    10, // Wake up at most 10 threads.
+                    ptr::null::<libc::timespec>(),
+                    0usize,
+                    0b1001, // bitset
+                ),
+                0, // Didn't match any thread.
+            );
+        }
+        thread::sleep(Duration::from_millis(200));
+        unsafe {
+            assert_eq!(
+                libc::syscall(
+                    libc::SYS_futex,
+                    &FUTEX as *const i32,
+                    libc::FUTEX_WAKE_BITSET,
+                    10, // Wake up at most 10 threads.
+                    ptr::null::<libc::timespec>(),
+                    0usize,
+                    0b0110, // bitset
+                ),
+                1, // Woken up one thread.
+            );
+        }
+    });
+
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_futex,
+                &FUTEX as *const i32,
+                libc::FUTEX_WAIT_BITSET,
+                0,
+                ptr::null::<libc::timespec>(),
+                0usize,
+                0b0100, // bitset
+            ),
+            0,
+        );
+    }
+
+    assert!((400..1000).contains(&start.elapsed().as_millis()));
+    t.join().unwrap();
+}
+
+fn concurrent_wait_wake() {
+    const FREE: i32 = 0;
+    const HELD: i32 = 1;
+
+    static FUTEX: AtomicI32 = AtomicI32::new(0);
+    static mut DATA: i32 = 0;
+    static WOKEN: AtomicI32 = AtomicI32::new(0);
+
+    let rounds = 50;
+    for _ in 0..rounds {
+        unsafe { DATA = 0 }; // Reset
+        // Suppose the main thread is holding a lock implemented using futex...
+        FUTEX.store(HELD, Ordering::Relaxed);
+
+        let t = thread::spawn(move || {
+            // If this syscall runs first, then we'll be woken up by
+            // the main thread's FUTEX_WAKE, and all is fine.
+            //
+            // If this sycall runs after the main thread's store
+            // and FUTEX_WAKE, the syscall must observe that
+            // the FUTEX is FREE != HELD and return without waiting
+            // or we'll deadlock.
+            unsafe {
+                let ret = libc::syscall(
+                    libc::SYS_futex,
+                    &FUTEX as *const AtomicI32,
+                    libc::FUTEX_WAIT,
+                    HELD,
+                    ptr::null::<libc::timespec>(),
+                );
+                if ret == 0 {
+                    // We actually slept. And then woke up again. So we should be ordered-after
+                    // what happened-before the FUTEX_WAKE. So this is not a race.
+                    assert_eq!(DATA, 1);
+                    // Also remember that this happened at least once.
+                    WOKEN.fetch_add(1, Ordering::Relaxed);
+                }
+            }
+        });
+        // Increase the chance that the other thread actually goes to sleep.
+        // (5 yields in a loop seem to make that happen around 40% of the time.)
+        for _ in 0..5 {
+            thread::yield_now();
+        }
+
+        FUTEX.store(FREE, Ordering::Relaxed);
+        unsafe {
+            DATA = 1;
+            libc::syscall(libc::SYS_futex, &FUTEX as *const AtomicI32, libc::FUTEX_WAKE, 1);
+        }
+
+        t.join().unwrap();
+    }
+
+    // Make sure we got the interesting case (of having woken a thread) at least once, but not *each* time.
+    let woken = WOKEN.load(Ordering::Relaxed);
+    //eprintln!("waking happened {woken} times");
+    assert!(woken > 0 && woken < rounds);
+}
+
+fn main() {
+    wake_nobody();
+    wake_dangling();
+    wait_wrong_val();
+    wait_timeout();
+    wait_absolute_timeout();
+    wait_wake();
+    wait_wake_bitset();
+    concurrent_wait_wake();
+}
diff --git a/src/tools/miri/tests/pass-dep/concurrency/tls_pthread_drop_order.rs b/src/tools/miri/tests/pass-dep/concurrency/tls_pthread_drop_order.rs
new file mode 100644
index 000000000000..6516396ac540
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/concurrency/tls_pthread_drop_order.rs
@@ -0,0 +1,73 @@
+//@ignore-target-windows: No libc on Windows
+//! Test that pthread_key destructors are run in the right order.
+//! Note that these are *not* used by actual `thread_local!` on Linux! Those use
+//! `thread_local_dtor::register_dtor` from the stdlib instead. In Miri this hits the fallback path
+//! in `register_dtor_fallback`, which uses a *single* pthread_key to manage a thread-local list of
+//! dtors to call.
+
+use std::mem;
+use std::ptr;
+
+pub type Key = libc::pthread_key_t;
+
+static mut RECORD: usize = 0;
+static mut KEYS: [Key; 2] = [0; 2];
+static mut GLOBALS: [u64; 2] = [1, 0];
+
+static mut CANNARY: *mut u64 = ptr::null_mut(); // this serves as a cannary: if TLS dtors are not run properly, this will not get deallocated, making the test fail.
+
+pub unsafe fn create(dtor: Option<unsafe extern "C" fn(*mut u8)>) -> Key {
+    let mut key = 0;
+    assert_eq!(libc::pthread_key_create(&mut key, mem::transmute(dtor)), 0);
+    key
+}
+
+pub unsafe fn set(key: Key, value: *mut u8) {
+    let r = libc::pthread_setspecific(key, value as *mut _);
+    assert_eq!(r, 0);
+}
+
+pub fn record(r: usize) {
+    assert!(r < 10);
+    unsafe { RECORD = RECORD * 10 + r };
+}
+
+unsafe extern "C" fn dtor(ptr: *mut u64) {
+    assert!(CANNARY != ptr::null_mut()); // make sure we do not get run too often
+    let val = *ptr;
+
+    let which_key =
+        GLOBALS.iter().position(|global| global as *const _ == ptr).expect("Should find my global");
+    record(which_key);
+
+    if val > 0 {
+        *ptr = val - 1;
+        set(KEYS[which_key], ptr as *mut _);
+    }
+
+    // Check if the records matches what we expect. If yes, clear the cannary.
+    // If the record is wrong, the cannary will never get cleared, leading to a leak -> test fails.
+    // If the record is incomplete (i.e., more dtor calls happen), the check at the beginning of this function will fail -> test fails.
+    // The correct sequence is: First key 0, then key 1, then key 0.
+    // Note that this relies on dtor order, which is not specified by POSIX, but seems to be
+    // consistent between Miri and Linux currently (as of Aug 2022).
+    if RECORD == 0_1_0 {
+        drop(Box::from_raw(CANNARY));
+        CANNARY = ptr::null_mut();
+    }
+}
+
+fn main() {
+    unsafe {
+        create(None); // check that the no-dtor case works
+
+        // Initialize the keys we use to check destructor ordering
+        for (key, global) in KEYS.iter_mut().zip(GLOBALS.iter_mut()) {
+            *key = create(Some(mem::transmute(dtor as unsafe extern "C" fn(*mut u64))));
+            set(*key, global as *mut _ as *mut u8);
+        }
+
+        // Initialize cannary
+        CANNARY = Box::into_raw(Box::new(0u64));
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/foreign-fn-linkname.rs b/src/tools/miri/tests/pass-dep/foreign-fn-linkname.rs
new file mode 100644
index 000000000000..9f090a4eff5d
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/foreign-fn-linkname.rs
@@ -0,0 +1,20 @@
+use std::ffi::CString;
+
+mod mlibc {
+    use libc::{c_char, size_t};
+    extern "C" {
+        #[link_name = "strlen"]
+        pub fn my_strlen(str: *const c_char) -> size_t;
+    }
+}
+
+fn strlen(str: String) -> usize {
+    // C string is terminated with a zero
+    let s = CString::new(str).unwrap();
+    unsafe { mlibc::my_strlen(s.as_ptr()) as usize }
+}
+
+pub fn main() {
+    let len = strlen("Rust".to_string());
+    assert_eq!(len, 4);
+}
diff --git a/src/tools/miri/tests/pass-dep/malloc.rs b/src/tools/miri/tests/pass-dep/malloc.rs
new file mode 100644
index 000000000000..f5e014c000d1
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/malloc.rs
@@ -0,0 +1,49 @@
+//@ignore-target-windows: No libc on Windows
+
+use core::{ptr, slice};
+
+fn main() {
+    // Test that small allocations sometimes *are* not very aligned.
+    let saw_unaligned = (0..64).any(|_| unsafe {
+        let p = libc::malloc(3);
+        libc::free(p);
+        (p as usize) % 4 != 0 // find any that this is *not* 4-aligned
+    });
+    assert!(saw_unaligned);
+
+    unsafe {
+        // Use calloc for initialized memory
+        let p1 = libc::calloc(20, 1);
+
+        // old size < new size
+        let p2 = libc::realloc(p1, 40);
+        let slice = slice::from_raw_parts(p2 as *const u8, 20);
+        assert_eq!(&slice, &[0_u8; 20]);
+
+        // old size == new size
+        let p3 = libc::realloc(p2, 40);
+        let slice = slice::from_raw_parts(p3 as *const u8, 20);
+        assert_eq!(&slice, &[0_u8; 20]);
+
+        // old size > new size
+        let p4 = libc::realloc(p3, 10);
+        let slice = slice::from_raw_parts(p4 as *const u8, 10);
+        assert_eq!(&slice, &[0_u8; 10]);
+
+        libc::free(p4);
+    }
+
+    unsafe {
+        let p1 = libc::malloc(20);
+
+        let p2 = libc::realloc(p1, 0);
+        assert!(p2.is_null());
+    }
+
+    unsafe {
+        let p1 = libc::realloc(ptr::null_mut(), 20);
+        assert!(!p1.is_null());
+
+        libc::free(p1);
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/num_cpus.rs b/src/tools/miri/tests/pass-dep/num_cpus.rs
new file mode 100644
index 000000000000..84339feb11e1
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/num_cpus.rs
@@ -0,0 +1,5 @@
+//@compile-flags: -Zmiri-disable-isolation
+
+fn main() {
+    assert_eq!(num_cpus::get(), 1);
+}
diff --git a/src/tools/miri/tests/pass-dep/page_size.rs b/src/tools/miri/tests/pass-dep/page_size.rs
new file mode 100644
index 000000000000..cdcabf333381
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/page_size.rs
@@ -0,0 +1,6 @@
+fn main() {
+    let page_size = page_size::get();
+
+    // In particular, this checks that it is not 0.
+    assert!(page_size.is_power_of_two(), "page size not a power of two: {}", page_size);
+}
diff --git a/src/tools/miri/tests/pass-dep/random.rs b/src/tools/miri/tests/pass-dep/random.rs
new file mode 100644
index 000000000000..5eccf3b0ea11
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/random.rs
@@ -0,0 +1,22 @@
+// mac-os `getrandom_1` does some pointer shenanigans
+//@compile-flags: -Zmiri-permissive-provenance
+use rand::{rngs::SmallRng, Rng, SeedableRng};
+
+fn main() {
+    // Test `getrandom` directly (in multiple different versions).
+    let mut data = vec![0; 16];
+    getrandom_1::getrandom(&mut data).unwrap();
+    getrandom_2::getrandom(&mut data).unwrap();
+
+    // Try seeding with "real" entropy.
+    let mut rng = SmallRng::from_entropy();
+    let _val = rng.gen::<i32>();
+    let _val = rng.gen::<isize>();
+    let _val = rng.gen::<i128>();
+
+    // Also try per-thread RNG.
+    let mut rng = rand::thread_rng();
+    let _val = rng.gen::<i32>();
+    let _val = rng.gen::<isize>();
+    let _val = rng.gen::<i128>();
+}
diff --git a/src/tools/miri/tests/pass-dep/regions-mock-trans.rs b/src/tools/miri/tests/pass-dep/regions-mock-trans.rs
new file mode 100644
index 000000000000..57f1b75f4d52
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/regions-mock-trans.rs
@@ -0,0 +1,45 @@
+use std::mem;
+
+struct Arena(());
+
+struct Bcx<'a> {
+    fcx: &'a Fcx<'a>,
+}
+
+#[allow(dead_code)]
+struct Fcx<'a> {
+    arena: &'a Arena,
+    ccx: &'a Ccx,
+}
+
+#[allow(dead_code)]
+struct Ccx {
+    x: isize,
+}
+
+fn alloc<'a>(_bcx: &'a Arena) -> &'a mut Bcx<'a> {
+    unsafe { mem::transmute(libc::malloc(mem::size_of::<Bcx<'a>>() as libc::size_t)) }
+}
+
+fn h<'a>(bcx: &'a Bcx<'a>) -> &'a mut Bcx<'a> {
+    return alloc(bcx.fcx.arena);
+}
+
+fn g(fcx: &Fcx) {
+    let bcx = Bcx { fcx: fcx };
+    let bcx2 = h(&bcx);
+    unsafe {
+        libc::free(mem::transmute(bcx2));
+    }
+}
+
+fn f(ccx: &Ccx) {
+    let a = Arena(());
+    let fcx = Fcx { arena: &a, ccx: ccx };
+    return g(&fcx);
+}
+
+pub fn main() {
+    let ccx = Ccx { x: 0 };
+    f(&ccx);
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/env-cleanup-data-race.rs b/src/tools/miri/tests/pass-dep/shims/env-cleanup-data-race.rs
new file mode 100644
index 000000000000..d36ffe70321b
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/env-cleanup-data-race.rs
@@ -0,0 +1,23 @@
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-preemption-rate=0
+//@ignore-target-windows: No libc on Windows
+
+use std::ffi::CStr;
+use std::ffi::CString;
+use std::thread;
+
+fn main() {
+    unsafe {
+        thread::spawn(|| {
+            // Access the environment in another thread without taking the env lock
+            let k = CString::new("MIRI_ENV_VAR_TEST".as_bytes()).unwrap();
+            let s = libc::getenv(k.as_ptr()) as *const libc::c_char;
+            if s.is_null() {
+                panic!("null");
+            }
+            let _s = String::from_utf8_lossy(CStr::from_ptr(s).to_bytes());
+        });
+        thread::yield_now();
+        // After the main thread exits, env vars will be cleaned up -- but because we have not *joined*
+        // the other thread, those accesses technically race with those in the other thread.
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/fs.rs b/src/tools/miri/tests/pass-dep/shims/fs.rs
new file mode 100644
index 000000000000..9faced029161
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/fs.rs
@@ -0,0 +1,445 @@
+//@ignore-target-windows: File handling is not implemented yet
+//@compile-flags: -Zmiri-disable-isolation
+
+#![feature(io_error_more)]
+#![feature(io_error_uncategorized)]
+
+use std::ffi::CString;
+use std::fs::{
+    create_dir, read_dir, read_link, remove_dir, remove_dir_all, remove_file, rename, File,
+    OpenOptions,
+};
+use std::io::{Error, ErrorKind, Read, Result, Seek, SeekFrom, Write};
+use std::path::{Path, PathBuf};
+
+fn main() {
+    test_file();
+    test_file_clone();
+    test_file_create_new();
+    test_seek();
+    test_metadata();
+    test_file_set_len();
+    test_file_sync();
+    test_symlink();
+    test_errors();
+    test_rename();
+    test_directory();
+    test_canonicalize();
+    test_dup_stdout_stderr();
+    test_from_raw_os_error();
+
+    // These all require unix, if the test is changed to no longer `ignore-windows`, move these to a unix test
+    test_file_open_unix_allow_two_args();
+    test_file_open_unix_needs_three_args();
+    test_file_open_unix_extra_third_arg();
+}
+
+fn tmp() -> PathBuf {
+    std::env::var("MIRI_TEMP")
+        .map(|tmp| {
+            // MIRI_TEMP is set outside of our emulated
+            // program, so it may have path separators that don't
+            // correspond to our target platform. We normalize them here
+            // before constructing a `PathBuf`
+
+            #[cfg(windows)]
+            return PathBuf::from(tmp.replace("/", "\\"));
+
+            #[cfg(not(windows))]
+            return PathBuf::from(tmp.replace("\\", "/"));
+        })
+        .unwrap_or_else(|_| std::env::temp_dir())
+}
+
+/// Prepare: compute filename and make sure the file does not exist.
+fn prepare(filename: &str) -> PathBuf {
+    let path = tmp().join(filename);
+    // Clean the paths for robustness.
+    remove_file(&path).ok();
+    path
+}
+
+/// Prepare directory: compute directory name and make sure it does not exist.
+fn prepare_dir(dirname: &str) -> PathBuf {
+    let path = tmp().join(&dirname);
+    // Clean the directory for robustness.
+    remove_dir_all(&path).ok();
+    path
+}
+
+/// Prepare like above, and also write some initial content to the file.
+fn prepare_with_content(filename: &str, content: &[u8]) -> PathBuf {
+    let path = prepare(filename);
+    let mut file = File::create(&path).unwrap();
+    file.write(content).unwrap();
+    path
+}
+
+fn test_file() {
+    let bytes = b"Hello, World!\n";
+    let path = prepare("miri_test_fs_file.txt");
+
+    // Test creating, writing and closing a file (closing is tested when `file` is dropped).
+    let mut file = File::create(&path).unwrap();
+    // Writing 0 bytes should not change the file contents.
+    file.write(&mut []).unwrap();
+    assert_eq!(file.metadata().unwrap().len(), 0);
+
+    file.write(bytes).unwrap();
+    assert_eq!(file.metadata().unwrap().len(), bytes.len() as u64);
+    // Test opening, reading and closing a file.
+    let mut file = File::open(&path).unwrap();
+    let mut contents = Vec::new();
+    // Reading 0 bytes should not move the file pointer.
+    file.read(&mut []).unwrap();
+    // Reading until EOF should get the whole text.
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(bytes, contents.as_slice());
+
+    // Removing file should succeed.
+    remove_file(&path).unwrap();
+}
+
+fn test_file_open_unix_allow_two_args() {
+    use std::os::unix::ffi::OsStrExt;
+
+    let path = prepare_with_content("test_file_open_unix_allow_two_args.txt", &[]);
+
+    let mut name = path.into_os_string();
+    name.push("\0");
+    let name_ptr = name.as_bytes().as_ptr().cast::<libc::c_char>();
+    let _fd = unsafe { libc::open(name_ptr, libc::O_RDONLY) };
+}
+
+fn test_file_open_unix_needs_three_args() {
+    use std::os::unix::ffi::OsStrExt;
+
+    let path = prepare_with_content("test_file_open_unix_needs_three_args.txt", &[]);
+
+    let mut name = path.into_os_string();
+    name.push("\0");
+    let name_ptr = name.as_bytes().as_ptr().cast::<libc::c_char>();
+    let _fd = unsafe { libc::open(name_ptr, libc::O_CREAT, 0o666) };
+}
+
+fn test_file_open_unix_extra_third_arg() {
+    use std::os::unix::ffi::OsStrExt;
+
+    let path = prepare_with_content("test_file_open_unix_extra_third_arg.txt", &[]);
+
+    let mut name = path.into_os_string();
+    name.push("\0");
+    let name_ptr = name.as_bytes().as_ptr().cast::<libc::c_char>();
+    let _fd = unsafe { libc::open(name_ptr, libc::O_RDONLY, 42) };
+}
+
+fn test_file_clone() {
+    let bytes = b"Hello, World!\n";
+    let path = prepare_with_content("miri_test_fs_file_clone.txt", bytes);
+
+    // Cloning a file should be successful.
+    let file = File::open(&path).unwrap();
+    let mut cloned = file.try_clone().unwrap();
+    // Reading from a cloned file should get the same text.
+    let mut contents = Vec::new();
+    cloned.read_to_end(&mut contents).unwrap();
+    assert_eq!(bytes, contents.as_slice());
+
+    // Removing file should succeed.
+    remove_file(&path).unwrap();
+}
+
+fn test_file_create_new() {
+    let path = prepare("miri_test_fs_file_create_new.txt");
+
+    // Creating a new file that doesn't yet exist should succeed.
+    OpenOptions::new().write(true).create_new(true).open(&path).unwrap();
+    // Creating a new file that already exists should fail.
+    assert_eq!(
+        ErrorKind::AlreadyExists,
+        OpenOptions::new().write(true).create_new(true).open(&path).unwrap_err().kind()
+    );
+    // Optionally creating a new file that already exists should succeed.
+    OpenOptions::new().write(true).create(true).open(&path).unwrap();
+
+    // Clean up
+    remove_file(&path).unwrap();
+}
+
+fn test_seek() {
+    let bytes = b"Hello, entire World!\n";
+    let path = prepare_with_content("miri_test_fs_seek.txt", bytes);
+
+    let mut file = File::open(&path).unwrap();
+    let mut contents = Vec::new();
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(bytes, contents.as_slice());
+    // Test that seeking to the beginning and reading until EOF gets the text again.
+    file.seek(SeekFrom::Start(0)).unwrap();
+    let mut contents = Vec::new();
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(bytes, contents.as_slice());
+    // Test seeking relative to the end of the file.
+    file.seek(SeekFrom::End(-1)).unwrap();
+    let mut contents = Vec::new();
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(&bytes[bytes.len() - 1..], contents.as_slice());
+    // Test seeking relative to the current position.
+    file.seek(SeekFrom::Start(5)).unwrap();
+    file.seek(SeekFrom::Current(-3)).unwrap();
+    let mut contents = Vec::new();
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(&bytes[2..], contents.as_slice());
+
+    // Removing file should succeed.
+    remove_file(&path).unwrap();
+}
+
+fn check_metadata(bytes: &[u8], path: &Path) -> Result<()> {
+    // Test that the file metadata is correct.
+    let metadata = path.metadata()?;
+    // `path` should point to a file.
+    assert!(metadata.is_file());
+    // The size of the file must be equal to the number of written bytes.
+    assert_eq!(bytes.len() as u64, metadata.len());
+    Ok(())
+}
+
+fn test_metadata() {
+    let bytes = b"Hello, meta-World!\n";
+    let path = prepare_with_content("miri_test_fs_metadata.txt", bytes);
+
+    // Test that metadata of an absolute path is correct.
+    check_metadata(bytes, &path).unwrap();
+    // Test that metadata of a relative path is correct.
+    std::env::set_current_dir(path.parent().unwrap()).unwrap();
+    check_metadata(bytes, Path::new(path.file_name().unwrap())).unwrap();
+
+    // Removing file should succeed.
+    remove_file(&path).unwrap();
+}
+
+fn test_file_set_len() {
+    let bytes = b"Hello, World!\n";
+    let path = prepare_with_content("miri_test_fs_set_len.txt", bytes);
+
+    // Test extending the file
+    let mut file = OpenOptions::new().read(true).write(true).open(&path).unwrap();
+    let bytes_extended = b"Hello, World!\n\x00\x00\x00\x00\x00\x00";
+    file.set_len(20).unwrap();
+    let mut contents = Vec::new();
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(bytes_extended, contents.as_slice());
+
+    // Test truncating the file
+    file.seek(SeekFrom::Start(0)).unwrap();
+    file.set_len(10).unwrap();
+    let mut contents = Vec::new();
+    file.read_to_end(&mut contents).unwrap();
+    assert_eq!(&bytes[..10], contents.as_slice());
+
+    // Can't use set_len on a file not opened for writing
+    let file = OpenOptions::new().read(true).open(&path).unwrap();
+    assert_eq!(ErrorKind::InvalidInput, file.set_len(14).unwrap_err().kind());
+
+    remove_file(&path).unwrap();
+}
+
+fn test_file_sync() {
+    let bytes = b"Hello, World!\n";
+    let path = prepare_with_content("miri_test_fs_sync.txt", bytes);
+
+    // Test that we can call sync_data and sync_all (can't readily test effects of this operation)
+    let file = OpenOptions::new().write(true).open(&path).unwrap();
+    file.sync_data().unwrap();
+    file.sync_all().unwrap();
+
+    // Test that we can call sync_data and sync_all on a file opened for reading.
+    let file = File::open(&path).unwrap();
+    file.sync_data().unwrap();
+    file.sync_all().unwrap();
+
+    remove_file(&path).unwrap();
+}
+
+fn test_symlink() {
+    let bytes = b"Hello, World!\n";
+    let path = prepare_with_content("miri_test_fs_link_target.txt", bytes);
+    let symlink_path = prepare("miri_test_fs_symlink.txt");
+
+    // Creating a symbolic link should succeed.
+    #[cfg(unix)]
+    std::os::unix::fs::symlink(&path, &symlink_path).unwrap();
+    #[cfg(windows)]
+    std::os::windows::fs::symlink_file(&path, &symlink_path).unwrap();
+    // Test that the symbolic link has the same contents as the file.
+    let mut symlink_file = File::open(&symlink_path).unwrap();
+    let mut contents = Vec::new();
+    symlink_file.read_to_end(&mut contents).unwrap();
+    assert_eq!(bytes, contents.as_slice());
+
+    #[cfg(unix)]
+    {
+        use std::os::unix::ffi::OsStrExt;
+
+        let expected_path = path.as_os_str().as_bytes();
+
+        // Test that the expected string gets written to a buffer of proper
+        // length, and that a trailing null byte is not written.
+        let symlink_c_str = CString::new(symlink_path.as_os_str().as_bytes()).unwrap();
+        let symlink_c_ptr = symlink_c_str.as_ptr();
+
+        // Make the buf one byte larger than it needs to be,
+        // and check that the last byte is not overwritten.
+        let mut large_buf = vec![0xFF; expected_path.len() + 1];
+        let res = unsafe {
+            libc::readlink(symlink_c_ptr, large_buf.as_mut_ptr().cast(), large_buf.len())
+        };
+        // Check that the resovled path was properly written into the buf.
+        assert_eq!(&large_buf[..(large_buf.len() - 1)], expected_path);
+        assert_eq!(large_buf.last(), Some(&0xFF));
+        assert_eq!(res, large_buf.len() as isize - 1);
+
+        // Test that the resolved path is truncated if the provided buffer
+        // is too small.
+        let mut small_buf = [0u8; 2];
+        let res = unsafe {
+            libc::readlink(symlink_c_ptr, small_buf.as_mut_ptr().cast(), small_buf.len())
+        };
+        assert_eq!(small_buf, &expected_path[..small_buf.len()]);
+        assert_eq!(res, small_buf.len() as isize);
+
+        // Test that we report a proper error for a missing path.
+        let bad_path = CString::new("MIRI_MISSING_FILE_NAME").unwrap();
+        let res = unsafe {
+            libc::readlink(bad_path.as_ptr(), small_buf.as_mut_ptr().cast(), small_buf.len())
+        };
+        assert_eq!(res, -1);
+        assert_eq!(Error::last_os_error().kind(), ErrorKind::NotFound);
+    }
+
+    // Test that metadata of a symbolic link (i.e., the file it points to) is correct.
+    check_metadata(bytes, &symlink_path).unwrap();
+    // Test that the metadata of a symbolic link is correct when not following it.
+    assert!(symlink_path.symlink_metadata().unwrap().file_type().is_symlink());
+    // Check that we can follow the link.
+    assert_eq!(read_link(&symlink_path).unwrap(), path);
+    // Removing symbolic link should succeed.
+    remove_file(&symlink_path).unwrap();
+
+    // Removing file should succeed.
+    remove_file(&path).unwrap();
+}
+
+fn test_errors() {
+    let bytes = b"Hello, World!\n";
+    let path = prepare("miri_test_fs_errors.txt");
+
+    // The following tests also check that the `__errno_location()` shim is working properly.
+    // Opening a non-existing file should fail with a "not found" error.
+    assert_eq!(ErrorKind::NotFound, File::open(&path).unwrap_err().kind());
+    // Make sure we can also format this.
+    format!("{0:?}: {0}", File::open(&path).unwrap_err());
+    // Removing a non-existing file should fail with a "not found" error.
+    assert_eq!(ErrorKind::NotFound, remove_file(&path).unwrap_err().kind());
+    // Reading the metadata of a non-existing file should fail with a "not found" error.
+    assert_eq!(ErrorKind::NotFound, check_metadata(bytes, &path).unwrap_err().kind());
+}
+
+fn test_rename() {
+    // Renaming a file should succeed.
+    let path1 = prepare("miri_test_fs_rename_source.txt");
+    let path2 = prepare("miri_test_fs_rename_destination.txt");
+
+    let file = File::create(&path1).unwrap();
+    drop(file);
+
+    // Renaming should succeed
+    rename(&path1, &path2).unwrap();
+    // Check that the old file path isn't present
+    assert_eq!(ErrorKind::NotFound, path1.metadata().unwrap_err().kind());
+    // Check that the file has moved successfully
+    assert!(path2.metadata().unwrap().is_file());
+
+    // Renaming a nonexistent file should fail
+    assert_eq!(ErrorKind::NotFound, rename(&path1, &path2).unwrap_err().kind());
+
+    remove_file(&path2).unwrap();
+}
+
+fn test_canonicalize() {
+    use std::fs::canonicalize;
+    let dir_path = prepare_dir("miri_test_fs_dir");
+    create_dir(&dir_path).unwrap();
+    let path = dir_path.join("test_file");
+    drop(File::create(&path).unwrap());
+
+    let p = canonicalize(format!("{}/./test_file", dir_path.to_string_lossy())).unwrap();
+    assert_eq!(p.to_string_lossy().find('.'), None);
+
+    remove_dir_all(&dir_path).unwrap();
+
+    // Make sure we get an error for long paths.
+    use std::convert::TryInto;
+    let too_long = "x/".repeat(libc::PATH_MAX.try_into().unwrap());
+    assert!(canonicalize(too_long).is_err());
+}
+
+fn test_directory() {
+    let dir_path = prepare_dir("miri_test_fs_dir");
+    // Creating a directory should succeed.
+    create_dir(&dir_path).unwrap();
+    // Test that the metadata of a directory is correct.
+    assert!(dir_path.metadata().unwrap().is_dir());
+    // Creating a directory when it already exists should fail.
+    assert_eq!(ErrorKind::AlreadyExists, create_dir(&dir_path).unwrap_err().kind());
+
+    // Create some files inside the directory
+    let path_1 = dir_path.join("test_file_1");
+    drop(File::create(&path_1).unwrap());
+    let path_2 = dir_path.join("test_file_2");
+    drop(File::create(&path_2).unwrap());
+    // Test that the files are present inside the directory
+    let dir_iter = read_dir(&dir_path).unwrap();
+    let mut file_names = dir_iter.map(|e| e.unwrap().file_name()).collect::<Vec<_>>();
+    file_names.sort_unstable();
+    assert_eq!(file_names, vec!["test_file_1", "test_file_2"]);
+    // Deleting the directory should fail, since it is not empty.
+    assert_eq!(ErrorKind::DirectoryNotEmpty, remove_dir(&dir_path).unwrap_err().kind());
+    // Clean up the files in the directory
+    remove_file(&path_1).unwrap();
+    remove_file(&path_2).unwrap();
+    // Now there should be nothing left in the directory.
+    let dir_iter = read_dir(&dir_path).unwrap();
+    let file_names = dir_iter.map(|e| e.unwrap().file_name()).collect::<Vec<_>>();
+    assert!(file_names.is_empty());
+
+    // Deleting the directory should succeed.
+    remove_dir(&dir_path).unwrap();
+    // Reading the metadata of a non-existent directory should fail with a "not found" error.
+    assert_eq!(ErrorKind::NotFound, check_metadata(&[], &dir_path).unwrap_err().kind());
+
+    // To test remove_dir_all, re-create the directory with a file and a directory in it.
+    create_dir(&dir_path).unwrap();
+    drop(File::create(&path_1).unwrap());
+    create_dir(&path_2).unwrap();
+    remove_dir_all(&dir_path).unwrap();
+}
+
+fn test_dup_stdout_stderr() {
+    let bytes = b"hello dup fd\n";
+    unsafe {
+        let new_stdout = libc::fcntl(1, libc::F_DUPFD, 0);
+        let new_stderr = libc::fcntl(2, libc::F_DUPFD, 0);
+        libc::write(new_stdout, bytes.as_ptr() as *const libc::c_void, bytes.len());
+        libc::write(new_stderr, bytes.as_ptr() as *const libc::c_void, bytes.len());
+    }
+}
+
+fn test_from_raw_os_error() {
+    let code = 6; // not a code that std or Miri know
+    let error = Error::from_raw_os_error(code);
+    assert!(matches!(error.kind(), ErrorKind::Uncategorized));
+    // Make sure we can also format this.
+    format!("{error:?}");
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/fs.stderr b/src/tools/miri/tests/pass-dep/shims/fs.stderr
new file mode 100644
index 000000000000..b6fa69e3d5d2
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/fs.stderr
@@ -0,0 +1 @@
+hello dup fd
diff --git a/src/tools/miri/tests/pass-dep/shims/fs.stdout b/src/tools/miri/tests/pass-dep/shims/fs.stdout
new file mode 100644
index 000000000000..b6fa69e3d5d2
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/fs.stdout
@@ -0,0 +1 @@
+hello dup fd
diff --git a/src/tools/miri/tests/pass-dep/shims/fs_with_isolation.rs b/src/tools/miri/tests/pass-dep/shims/fs_with_isolation.rs
new file mode 100644
index 000000000000..f5420dbc5538
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/fs_with_isolation.rs
@@ -0,0 +1,53 @@
+//@ignore-target-windows: File handling is not implemented yet
+//@compile-flags: -Zmiri-isolation-error=warn-nobacktrace
+//@normalize-stderr-test: "(stat(x)?)" -> "$$STAT"
+
+use std::ffi::CString;
+use std::fs::{self, File};
+use std::io::{Error, ErrorKind};
+use std::os::unix;
+
+fn main() {
+    // test `open`
+    assert_eq!(File::create("foo.txt").unwrap_err().kind(), ErrorKind::PermissionDenied);
+
+    // test `fcntl`
+    unsafe {
+        assert_eq!(libc::fcntl(1, libc::F_DUPFD, 0), -1);
+        assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EPERM));
+    }
+
+    // test `unlink`
+    assert_eq!(fs::remove_file("foo.txt").unwrap_err().kind(), ErrorKind::PermissionDenied);
+
+    // test `symlink`
+    assert_eq!(
+        unix::fs::symlink("foo.txt", "foo_link.txt").unwrap_err().kind(),
+        ErrorKind::PermissionDenied
+    );
+
+    // test `readlink`
+    let symlink_c_str = CString::new("foo.txt").unwrap();
+    let mut buf = vec![0; "foo_link.txt".len() + 1];
+    unsafe {
+        assert_eq!(libc::readlink(symlink_c_str.as_ptr(), buf.as_mut_ptr(), buf.len()), -1);
+        assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EACCES));
+    }
+
+    // test `stat`
+    assert_eq!(fs::metadata("foo.txt").unwrap_err().kind(), ErrorKind::PermissionDenied);
+    assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EACCES));
+
+    // test `rename`
+    assert_eq!(fs::rename("a.txt", "b.txt").unwrap_err().kind(), ErrorKind::PermissionDenied);
+
+    // test `mkdir`
+    assert_eq!(fs::create_dir("foo/bar").unwrap_err().kind(), ErrorKind::PermissionDenied);
+
+    // test `rmdir`
+    assert_eq!(fs::remove_dir("foo/bar").unwrap_err().kind(), ErrorKind::PermissionDenied);
+
+    // test `opendir`
+    assert_eq!(fs::read_dir("foo/bar").unwrap_err().kind(), ErrorKind::PermissionDenied);
+    assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EACCES));
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/fs_with_isolation.stderr b/src/tools/miri/tests/pass-dep/shims/fs_with_isolation.stderr
new file mode 100644
index 000000000000..ad75e42831b0
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/fs_with_isolation.stderr
@@ -0,0 +1,20 @@
+warning: `open` was made to return an error due to isolation
+
+warning: `fcntl` was made to return an error due to isolation
+
+warning: `unlink` was made to return an error due to isolation
+
+warning: `symlink` was made to return an error due to isolation
+
+warning: `readlink` was made to return an error due to isolation
+
+warning: `$STAT` was made to return an error due to isolation
+
+warning: `rename` was made to return an error due to isolation
+
+warning: `mkdir` was made to return an error due to isolation
+
+warning: `rmdir` was made to return an error due to isolation
+
+warning: `opendir` was made to return an error due to isolation
+
diff --git a/src/tools/miri/tests/pass-dep/shims/libc-misc.rs b/src/tools/miri/tests/pass-dep/shims/libc-misc.rs
new file mode 100644
index 000000000000..a883a3d967a3
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/libc-misc.rs
@@ -0,0 +1,305 @@
+//@ignore-target-windows: No libc on Windows
+//@compile-flags: -Zmiri-disable-isolation
+#![feature(io_error_more)]
+
+use std::fs::{remove_file, File};
+use std::os::unix::io::AsRawFd;
+use std::path::PathBuf;
+
+fn tmp() -> PathBuf {
+    std::env::var("MIRI_TEMP")
+        .map(|tmp| {
+            // MIRI_TEMP is set outside of our emulated
+            // program, so it may have path separators that don't
+            // correspond to our target platform. We normalize them here
+            // before constructing a `PathBuf`
+            return PathBuf::from(tmp.replace("\\", "/"));
+        })
+        .unwrap_or_else(|_| std::env::temp_dir())
+}
+
+/// Test allocating variant of `realpath`.
+fn test_posix_realpath_alloc() {
+    use std::ffi::OsString;
+    use std::ffi::{CStr, CString};
+    use std::os::unix::ffi::OsStrExt;
+    use std::os::unix::ffi::OsStringExt;
+
+    let buf;
+    let path = tmp().join("miri_test_libc_posix_realpath_alloc");
+    let c_path = CString::new(path.as_os_str().as_bytes()).expect("CString::new failed");
+
+    // Cleanup before test.
+    remove_file(&path).ok();
+    // Create file.
+    drop(File::create(&path).unwrap());
+    unsafe {
+        let r = libc::realpath(c_path.as_ptr(), std::ptr::null_mut());
+        assert!(!r.is_null());
+        buf = CStr::from_ptr(r).to_bytes().to_vec();
+        libc::free(r as *mut _);
+    }
+    let canonical = PathBuf::from(OsString::from_vec(buf));
+    assert_eq!(path.file_name(), canonical.file_name());
+
+    // Cleanup after test.
+    remove_file(&path).unwrap();
+}
+
+/// Test non-allocating variant of `realpath`.
+fn test_posix_realpath_noalloc() {
+    use std::ffi::{CStr, CString};
+    use std::os::unix::ffi::OsStrExt;
+
+    let path = tmp().join("miri_test_libc_posix_realpath_noalloc");
+    let c_path = CString::new(path.as_os_str().as_bytes()).expect("CString::new failed");
+
+    let mut v = vec![0; libc::PATH_MAX as usize];
+
+    // Cleanup before test.
+    remove_file(&path).ok();
+    // Create file.
+    drop(File::create(&path).unwrap());
+    unsafe {
+        let r = libc::realpath(c_path.as_ptr(), v.as_mut_ptr());
+        assert!(!r.is_null());
+    }
+    let c = unsafe { CStr::from_ptr(v.as_ptr()) };
+    let canonical = PathBuf::from(c.to_str().expect("CStr to str"));
+
+    assert_eq!(path.file_name(), canonical.file_name());
+
+    // Cleanup after test.
+    remove_file(&path).unwrap();
+}
+
+/// Test failure cases for `realpath`.
+fn test_posix_realpath_errors() {
+    use std::ffi::CString;
+    use std::io::ErrorKind;
+
+    // Test non-existent path returns an error.
+    let c_path = CString::new("./nothing_to_see_here").expect("CString::new failed");
+    let r = unsafe { libc::realpath(c_path.as_ptr(), std::ptr::null_mut()) };
+    assert!(r.is_null());
+    let e = std::io::Error::last_os_error();
+    assert_eq!(e.raw_os_error(), Some(libc::ENOENT));
+    assert_eq!(e.kind(), ErrorKind::NotFound);
+}
+
+#[cfg(any(target_os = "linux"))]
+fn test_posix_fadvise() {
+    use std::convert::TryInto;
+    use std::io::Write;
+
+    let path = tmp().join("miri_test_libc_posix_fadvise.txt");
+    // Cleanup before test
+    remove_file(&path).ok();
+
+    // Set up an open file
+    let mut file = File::create(&path).unwrap();
+    let bytes = b"Hello, World!\n";
+    file.write(bytes).unwrap();
+
+    // Test calling posix_fadvise on a file.
+    let result = unsafe {
+        libc::posix_fadvise(
+            file.as_raw_fd(),
+            0,
+            bytes.len().try_into().unwrap(),
+            libc::POSIX_FADV_DONTNEED,
+        )
+    };
+    drop(file);
+    remove_file(&path).unwrap();
+    assert_eq!(result, 0);
+}
+
+#[cfg(any(target_os = "linux"))]
+fn test_sync_file_range() {
+    use std::io::Write;
+
+    let path = tmp().join("miri_test_libc_sync_file_range.txt");
+    // Cleanup before test.
+    remove_file(&path).ok();
+
+    // Write to a file.
+    let mut file = File::create(&path).unwrap();
+    let bytes = b"Hello, World!\n";
+    file.write(bytes).unwrap();
+
+    // Test calling sync_file_range on the file.
+    let result_1 = unsafe {
+        libc::sync_file_range(
+            file.as_raw_fd(),
+            0,
+            0,
+            libc::SYNC_FILE_RANGE_WAIT_BEFORE
+                | libc::SYNC_FILE_RANGE_WRITE
+                | libc::SYNC_FILE_RANGE_WAIT_AFTER,
+        )
+    };
+    drop(file);
+
+    // Test calling sync_file_range on a file opened for reading.
+    let file = File::open(&path).unwrap();
+    let result_2 = unsafe {
+        libc::sync_file_range(
+            file.as_raw_fd(),
+            0,
+            0,
+            libc::SYNC_FILE_RANGE_WAIT_BEFORE
+                | libc::SYNC_FILE_RANGE_WRITE
+                | libc::SYNC_FILE_RANGE_WAIT_AFTER,
+        )
+    };
+    drop(file);
+
+    remove_file(&path).unwrap();
+    assert_eq!(result_1, 0);
+    assert_eq!(result_2, 0);
+}
+
+/// Tests whether each thread has its own `__errno_location`.
+fn test_thread_local_errno() {
+    #[cfg(target_os = "linux")]
+    use libc::__errno_location;
+    #[cfg(any(target_os = "macos", target_os = "freebsd"))]
+    use libc::__error as __errno_location;
+
+    unsafe {
+        *__errno_location() = 0xBEEF;
+        std::thread::spawn(|| {
+            assert_eq!(*__errno_location(), 0);
+            *__errno_location() = 0xBAD1DEA;
+            assert_eq!(*__errno_location(), 0xBAD1DEA);
+        })
+        .join()
+        .unwrap();
+        assert_eq!(*__errno_location(), 0xBEEF);
+    }
+}
+
+/// Tests whether clock support exists at all
+#[cfg(any(target_os = "linux"))]
+fn test_clocks() {
+    let mut tp = std::mem::MaybeUninit::<libc::timespec>::uninit();
+    let is_error = unsafe { libc::clock_gettime(libc::CLOCK_REALTIME, tp.as_mut_ptr()) };
+    assert_eq!(is_error, 0);
+    let is_error = unsafe { libc::clock_gettime(libc::CLOCK_REALTIME_COARSE, tp.as_mut_ptr()) };
+    assert_eq!(is_error, 0);
+    let is_error = unsafe { libc::clock_gettime(libc::CLOCK_MONOTONIC, tp.as_mut_ptr()) };
+    assert_eq!(is_error, 0);
+    let is_error = unsafe { libc::clock_gettime(libc::CLOCK_MONOTONIC_COARSE, tp.as_mut_ptr()) };
+    assert_eq!(is_error, 0);
+}
+
+fn test_posix_gettimeofday() {
+    let mut tp = std::mem::MaybeUninit::<libc::timeval>::uninit();
+    let tz = std::ptr::null_mut::<libc::timezone>();
+    #[cfg(target_os = "macos")] // `tz` has a different type on macOS
+    let tz = tz as *mut libc::c_void;
+    let is_error = unsafe { libc::gettimeofday(tp.as_mut_ptr(), tz) };
+    assert_eq!(is_error, 0);
+    let tv = unsafe { tp.assume_init() };
+    assert!(tv.tv_sec > 0);
+    assert!(tv.tv_usec >= 0); // Theoretically this could be 0.
+
+    // Test that non-null tz returns an error.
+    let mut tz = std::mem::MaybeUninit::<libc::timezone>::uninit();
+    let tz_ptr = tz.as_mut_ptr();
+    #[cfg(target_os = "macos")] // `tz` has a different type on macOS
+    let tz_ptr = tz_ptr as *mut libc::c_void;
+    let is_error = unsafe { libc::gettimeofday(tp.as_mut_ptr(), tz_ptr) };
+    assert_eq!(is_error, -1);
+}
+
+fn test_isatty() {
+    // Testing whether our isatty shim returns the right value would require controlling whether
+    // these streams are actually TTYs, which is hard.
+    // For now, we just check that these calls are supported at all.
+    unsafe {
+        libc::isatty(libc::STDIN_FILENO);
+        libc::isatty(libc::STDOUT_FILENO);
+        libc::isatty(libc::STDERR_FILENO);
+
+        // But when we open a file, it is definitely not a TTY.
+        let path = tmp().join("notatty.txt");
+        // Cleanup before test.
+        remove_file(&path).ok();
+        let file = File::create(&path).unwrap();
+
+        assert_eq!(libc::isatty(file.as_raw_fd()), 0);
+        assert_eq!(std::io::Error::last_os_error().raw_os_error().unwrap(), libc::ENOTTY);
+
+        // Cleanup after test.
+        drop(file);
+        remove_file(&path).unwrap();
+    }
+}
+
+fn test_posix_mkstemp() {
+    use std::ffi::CString;
+    use std::ffi::OsStr;
+    use std::os::unix::ffi::OsStrExt;
+    use std::os::unix::io::FromRawFd;
+    use std::path::Path;
+
+    let valid_template = "fooXXXXXX";
+    // C needs to own this as `mkstemp(3)` says:
+    // "Since it will be modified, `template` must not be a string constant, but
+    // should be declared as a character array."
+    // There seems to be no `as_mut_ptr` on `CString` so we need to use `into_raw`.
+    let ptr = CString::new(valid_template).unwrap().into_raw();
+    let fd = unsafe { libc::mkstemp(ptr) };
+    // Take ownership back in Rust to not leak memory.
+    let slice = unsafe { CString::from_raw(ptr) };
+    assert!(fd > 0);
+    let osstr = OsStr::from_bytes(slice.to_bytes());
+    let path: &Path = osstr.as_ref();
+    let name = path.file_name().unwrap().to_string_lossy();
+    assert!(name.ne("fooXXXXXX"));
+    assert!(name.starts_with("foo"));
+    assert_eq!(name.len(), 9);
+    assert_eq!(
+        name.chars().skip(3).filter(char::is_ascii_alphanumeric).collect::<Vec<char>>().len(),
+        6
+    );
+    let file = unsafe { File::from_raw_fd(fd) };
+    assert!(file.set_len(0).is_ok());
+
+    let invalid_templates = vec!["foo", "barXX", "XXXXXXbaz", "whatXXXXXXever", "X"];
+    for t in invalid_templates {
+        let ptr = CString::new(t).unwrap().into_raw();
+        let fd = unsafe { libc::mkstemp(ptr) };
+        let _ = unsafe { CString::from_raw(ptr) };
+        // "On error, -1 is returned, and errno is set to
+        // indicate the error"
+        assert_eq!(fd, -1);
+        let e = std::io::Error::last_os_error();
+        assert_eq!(e.raw_os_error(), Some(libc::EINVAL));
+        assert_eq!(e.kind(), std::io::ErrorKind::InvalidInput);
+    }
+}
+
+fn main() {
+    #[cfg(any(target_os = "linux"))]
+    test_posix_fadvise();
+
+    test_posix_gettimeofday();
+    test_posix_mkstemp();
+
+    test_posix_realpath_alloc();
+    test_posix_realpath_noalloc();
+    test_posix_realpath_errors();
+
+    #[cfg(any(target_os = "linux"))]
+    test_sync_file_range();
+
+    test_thread_local_errno();
+
+    #[cfg(any(target_os = "linux"))]
+    test_clocks();
+
+    test_isatty();
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/linux-getrandom-without-isolation.rs b/src/tools/miri/tests/pass-dep/shims/linux-getrandom-without-isolation.rs
new file mode 100644
index 000000000000..349b447569a4
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/linux-getrandom-without-isolation.rs
@@ -0,0 +1,41 @@
+//@only-target-linux
+//@compile-flags: -Zmiri-disable-isolation
+
+use std::ptr;
+
+fn main() {
+    let mut buf = [0u8; 5];
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_getrandom,
+                ptr::null_mut::<libc::c_void>(),
+                0 as libc::size_t,
+                0 as libc::c_uint,
+            ),
+            0,
+        );
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_getrandom,
+                buf.as_mut_ptr() as *mut libc::c_void,
+                5 as libc::size_t,
+                0 as libc::c_uint,
+            ),
+            5,
+        );
+
+        assert_eq!(
+            libc::getrandom(ptr::null_mut::<libc::c_void>(), 0 as libc::size_t, 0 as libc::c_uint),
+            0,
+        );
+        assert_eq!(
+            libc::getrandom(
+                buf.as_mut_ptr() as *mut libc::c_void,
+                5 as libc::size_t,
+                0 as libc::c_uint,
+            ),
+            5,
+        );
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/linux-getrandom.rs b/src/tools/miri/tests/pass-dep/shims/linux-getrandom.rs
new file mode 100644
index 000000000000..a1436c7319d3
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/linux-getrandom.rs
@@ -0,0 +1,40 @@
+//@only-target-linux
+
+use std::ptr;
+
+fn main() {
+    let mut buf = [0u8; 5];
+    unsafe {
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_getrandom,
+                ptr::null_mut::<libc::c_void>(),
+                0 as libc::size_t,
+                0 as libc::c_uint,
+            ),
+            0,
+        );
+        assert_eq!(
+            libc::syscall(
+                libc::SYS_getrandom,
+                buf.as_mut_ptr() as *mut libc::c_void,
+                5 as libc::size_t,
+                0 as libc::c_uint,
+            ),
+            5,
+        );
+
+        assert_eq!(
+            libc::getrandom(ptr::null_mut::<libc::c_void>(), 0 as libc::size_t, 0 as libc::c_uint),
+            0,
+        );
+        assert_eq!(
+            libc::getrandom(
+                buf.as_mut_ptr() as *mut libc::c_void,
+                5 as libc::size_t,
+                0 as libc::c_uint,
+            ),
+            5,
+        );
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/posix_memalign.rs b/src/tools/miri/tests/pass-dep/shims/posix_memalign.rs
new file mode 100644
index 000000000000..9bd8a00d68dc
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/posix_memalign.rs
@@ -0,0 +1,82 @@
+//@ignore-target-windows: No libc on Windows
+
+#![feature(pointer_is_aligned)]
+#![feature(strict_provenance)]
+
+use core::ptr;
+
+fn main() {
+    // A normal allocation.
+    unsafe {
+        let mut ptr: *mut libc::c_void = ptr::null_mut();
+        let align = 8;
+        let size = 64;
+        assert_eq!(libc::posix_memalign(&mut ptr, align, size), 0);
+        assert!(!ptr.is_null());
+        assert!(ptr.is_aligned_to(align));
+        ptr.cast::<u8>().write_bytes(1, size);
+        libc::free(ptr);
+    }
+
+    // Align > size.
+    unsafe {
+        let mut ptr: *mut libc::c_void = ptr::null_mut();
+        let align = 64;
+        let size = 8;
+        assert_eq!(libc::posix_memalign(&mut ptr, align, size), 0);
+        assert!(!ptr.is_null());
+        assert!(ptr.is_aligned_to(align));
+        ptr.cast::<u8>().write_bytes(1, size);
+        libc::free(ptr);
+    }
+
+    // Size not multiple of align
+    unsafe {
+        let mut ptr: *mut libc::c_void = ptr::null_mut();
+        let align = 16;
+        let size = 31;
+        assert_eq!(libc::posix_memalign(&mut ptr, align, size), 0);
+        assert!(!ptr.is_null());
+        assert!(ptr.is_aligned_to(align));
+        ptr.cast::<u8>().write_bytes(1, size);
+        libc::free(ptr);
+    }
+
+    // Size == 0
+    unsafe {
+        let mut ptr: *mut libc::c_void = ptr::null_mut();
+        let align = 64;
+        let size = 0;
+        assert_eq!(libc::posix_memalign(&mut ptr, align, size), 0);
+        // We are not required to return null if size == 0, but we currently do.
+        // It's fine to remove this assert if we start returning non-null pointers.
+        assert!(ptr.is_null());
+        assert!(ptr.is_aligned_to(align));
+        // Regardless of what we return, it must be `free`able.
+        libc::free(ptr);
+    }
+
+    // Non-power of 2 align
+    unsafe {
+        let mut ptr: *mut libc::c_void = ptr::invalid_mut(0x1234567);
+        let align = 15;
+        let size = 8;
+        assert_eq!(libc::posix_memalign(&mut ptr, align, size), libc::EINVAL);
+        // The pointer is not modified on failure, posix_memalign(3) says:
+        // > On Linux (and other systems), posix_memalign() does  not  modify  memptr  on failure.
+        // > A requirement standardizing this behavior was added in POSIX.1-2008 TC2.
+        assert_eq!(ptr.addr(), 0x1234567);
+    }
+
+    // Too small align (smaller than ptr)
+    unsafe {
+        let mut ptr: *mut libc::c_void = ptr::invalid_mut(0x1234567);
+        let align = std::mem::size_of::<usize>() / 2;
+        let size = 8;
+        assert_eq!(libc::posix_memalign(&mut ptr, align, size), libc::EINVAL);
+        // The pointer is not modified on failure, posix_memalign(3) says:
+        // > On Linux (and other systems), posix_memalign() does  not  modify  memptr  on failure.
+        // > A requirement standardizing this behavior was added in POSIX.1-2008 TC2.
+        assert_eq!(ptr.addr(), 0x1234567);
+    }
+}
diff --git a/src/tools/miri/tests/pass-dep/shims/pthreads.rs b/src/tools/miri/tests/pass-dep/shims/pthreads.rs
new file mode 100644
index 000000000000..d062eda7e90c
--- /dev/null
+++ b/src/tools/miri/tests/pass-dep/shims/pthreads.rs
@@ -0,0 +1,127 @@
+//@ignore-target-windows: No libc on Windows
+
+fn main() {
+    test_mutex_libc_init_recursive();
+    test_mutex_libc_init_normal();
+    test_mutex_libc_init_errorcheck();
+    test_rwlock_libc_static_initializer();
+
+    #[cfg(any(target_os = "linux"))]
+    test_mutex_libc_static_initializer_recursive();
+}
+
+fn test_mutex_libc_init_recursive() {
+    unsafe {
+        let mut attr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutexattr_init(&mut attr as *mut _), 0);
+        assert_eq!(
+            libc::pthread_mutexattr_settype(&mut attr as *mut _, libc::PTHREAD_MUTEX_RECURSIVE),
+            0,
+        );
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mut attr as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_trylock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_trylock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), libc::EPERM);
+        assert_eq!(libc::pthread_mutex_destroy(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutexattr_destroy(&mut attr as *mut _), 0);
+    }
+}
+
+fn test_mutex_libc_init_normal() {
+    unsafe {
+        let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        assert_eq!(
+            libc::pthread_mutexattr_settype(&mut mutexattr as *mut _, 0x12345678),
+            libc::EINVAL,
+        );
+        assert_eq!(
+            libc::pthread_mutexattr_settype(&mut mutexattr as *mut _, libc::PTHREAD_MUTEX_NORMAL),
+            0,
+        );
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mutexattr as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_trylock(&mut mutex as *mut _), libc::EBUSY);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_trylock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_destroy(&mut mutex as *mut _), 0);
+    }
+}
+
+fn test_mutex_libc_init_errorcheck() {
+    unsafe {
+        let mut mutexattr: libc::pthread_mutexattr_t = std::mem::zeroed();
+        assert_eq!(
+            libc::pthread_mutexattr_settype(
+                &mut mutexattr as *mut _,
+                libc::PTHREAD_MUTEX_ERRORCHECK,
+            ),
+            0,
+        );
+        let mut mutex: libc::pthread_mutex_t = std::mem::zeroed();
+        assert_eq!(libc::pthread_mutex_init(&mut mutex as *mut _, &mutexattr as *const _), 0);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_trylock(&mut mutex as *mut _), libc::EBUSY);
+        assert_eq!(libc::pthread_mutex_lock(&mut mutex as *mut _), libc::EDEADLK);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_trylock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), 0);
+        assert_eq!(libc::pthread_mutex_unlock(&mut mutex as *mut _), libc::EPERM);
+        assert_eq!(libc::pthread_mutex_destroy(&mut mutex as *mut _), 0);
+    }
+}
+
+// Only linux provides PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP,
+// libc for macOS just has the default PTHREAD_MUTEX_INITIALIZER.
+#[cfg(target_os = "linux")]
+fn test_mutex_libc_static_initializer_recursive() {
+    let mutex = std::cell::UnsafeCell::new(libc::PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP);
+    unsafe {
+        assert_eq!(libc::pthread_mutex_lock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_trylock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_unlock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_unlock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_trylock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_lock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_unlock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_unlock(mutex.get()), 0);
+        assert_eq!(libc::pthread_mutex_unlock(mutex.get()), libc::EPERM);
+        assert_eq!(libc::pthread_mutex_destroy(mutex.get()), 0);
+    }
+}
+
+// Testing the behavior of std::sync::RwLock does not fully exercise the pthread rwlock shims, we
+// need to go a layer deeper and test the behavior of the libc functions, because
+// std::sys::unix::rwlock::RWLock itself keeps track of write_locked and num_readers.
+fn test_rwlock_libc_static_initializer() {
+    let rw = std::cell::UnsafeCell::new(libc::PTHREAD_RWLOCK_INITIALIZER);
+    unsafe {
+        assert_eq!(libc::pthread_rwlock_rdlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_rdlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_unlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_tryrdlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_unlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_trywrlock(rw.get()), libc::EBUSY);
+        assert_eq!(libc::pthread_rwlock_unlock(rw.get()), 0);
+
+        assert_eq!(libc::pthread_rwlock_wrlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_tryrdlock(rw.get()), libc::EBUSY);
+        assert_eq!(libc::pthread_rwlock_trywrlock(rw.get()), libc::EBUSY);
+        assert_eq!(libc::pthread_rwlock_unlock(rw.get()), 0);
+
+        assert_eq!(libc::pthread_rwlock_trywrlock(rw.get()), 0);
+        assert_eq!(libc::pthread_rwlock_tryrdlock(rw.get()), libc::EBUSY);
+        assert_eq!(libc::pthread_rwlock_trywrlock(rw.get()), libc::EBUSY);
+        assert_eq!(libc::pthread_rwlock_unlock(rw.get()), 0);
+
+        assert_eq!(libc::pthread_rwlock_destroy(rw.get()), 0);
+    }
+}
diff --git a/src/tools/miri/tests/pass/0weak_memory_consistency.rs b/src/tools/miri/tests/pass/0weak_memory_consistency.rs
new file mode 100644
index 000000000000..f3820bd660d2
--- /dev/null
+++ b/src/tools/miri/tests/pass/0weak_memory_consistency.rs
@@ -0,0 +1,301 @@
+//@compile-flags: -Zmiri-ignore-leaks -Zmiri-disable-stacked-borrows
+
+// The following tests check whether our weak memory emulation produces
+// any inconsistent execution outcomes
+//
+// Due to the random nature of choosing valid stores, it is always
+// possible that our tests spuriously succeeds: even though our weak
+// memory emulation code has incorrectly identified a store in
+// modification order as being valid, it may be never chosen by
+// the RNG and never observed in our tests.
+//
+// To mitigate this, each test is ran enough times such that the chance
+// of spurious success is very low. These tests never supriously fail.
+
+// Test cases and their consistent outcomes are from
+// http://svr-pes20-cppmem.cl.cam.ac.uk/cppmem/
+// Based on
+// M. Batty, S. Owens, S. Sarkar, P. Sewell and T. Weber,
+// "Mathematizing C++ concurrency", ACM SIGPLAN Notices, vol. 46, no. 1, pp. 55-66, 2011.
+// Available: https://ss265.host.cs.st-andrews.ac.uk/papers/n3132.pdf.
+
+use std::sync::atomic::Ordering::*;
+use std::sync::atomic::{fence, AtomicBool, AtomicI32};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+// We can't create static items because we need to run each test
+// multiple times
+fn static_atomic(val: i32) -> &'static AtomicI32 {
+    let ret = Box::leak(Box::new(AtomicI32::new(val)));
+    ret.store(val, Relaxed); // work around https://github.com/rust-lang/miri/issues/2164
+    ret
+}
+fn static_atomic_bool(val: bool) -> &'static AtomicBool {
+    let ret = Box::leak(Box::new(AtomicBool::new(val)));
+    ret.store(val, Relaxed); // work around https://github.com/rust-lang/miri/issues/2164
+    ret
+}
+
+// Spins until it acquires a pre-determined value.
+fn acquires_value(loc: &AtomicI32, val: i32) -> i32 {
+    while loc.load(Acquire) != val {
+        std::hint::spin_loop();
+    }
+    val
+}
+
+fn test_corr() {
+    let x = static_atomic(0);
+    let y = static_atomic(0);
+
+    let j1 = spawn(move || {
+        x.store(1, Relaxed);
+        x.store(2, Relaxed);
+    });
+
+    #[rustfmt::skip]
+    let j2 = spawn(move || {
+        let r2 = x.load(Relaxed); // -------------------------------------+
+        y.store(1, Release); // ---------------------+                    |
+        r2 //                                        |                    |
+    }); //                                           |                    |
+    #[rustfmt::skip] //                              |synchronizes-with   |happens-before
+    let j3 = spawn(move || { //                      |                    |
+        acquires_value(&y, 1); // <------------------+                    |
+        x.load(Relaxed) // <----------------------------------------------+
+        // The two reads on x are ordered by hb, so they cannot observe values
+        // differently from the modification order. If the first read observed
+        // 2, then the second read must observe 2 as well.
+    });
+
+    j1.join().unwrap();
+    let r2 = j2.join().unwrap();
+    let r3 = j3.join().unwrap();
+    if r2 == 2 {
+        assert_eq!(r3, 2);
+    }
+}
+
+fn test_wrc() {
+    let x = static_atomic(0);
+    let y = static_atomic(0);
+
+    #[rustfmt::skip]
+    let j1 = spawn(move || {
+        x.store(1, Release); // ---------------------+---------------------+
+    }); //                                           |                     |
+    #[rustfmt::skip] //                              |synchronizes-with    |
+    let j2 = spawn(move || { //                      |                     |
+        acquires_value(&x, 1); // <------------------+                     |
+        y.store(1, Release); // ---------------------+                     |happens-before
+    }); //                                           |                     |
+    #[rustfmt::skip] //                              |synchronizes-with    |
+    let j3 = spawn(move || { //                      |                     |
+        acquires_value(&y, 1); // <------------------+                     |
+        x.load(Relaxed) // <-----------------------------------------------+
+    });
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+    let r3 = j3.join().unwrap();
+
+    assert_eq!(r3, 1);
+}
+
+fn test_message_passing() {
+    let mut var = 0u32;
+    let ptr = &mut var as *mut u32;
+    let x = EvilSend(ptr);
+    let y = static_atomic(0);
+
+    #[rustfmt::skip]
+    let j1 = spawn(move || {
+        unsafe { *x.0 = 1 }; // -----------------------------------------+
+        y.store(1, Release); // ---------------------+                   |
+    }); //                                           |                   |
+    #[rustfmt::skip] //                              |synchronizes-with  | happens-before
+    let j2 = spawn(move || { //                      |                   |
+        acquires_value(&y, 1); // <------------------+                   |
+        unsafe { *x.0 } // <---------------------------------------------+
+    });
+
+    j1.join().unwrap();
+    let r2 = j2.join().unwrap();
+
+    assert_eq!(r2, 1);
+}
+
+// LB+acq_rel+acq_rel
+fn test_load_buffering_acq_rel() {
+    let x = static_atomic(0);
+    let y = static_atomic(0);
+    let j1 = spawn(move || {
+        let r1 = x.load(Acquire);
+        y.store(1, Release);
+        r1
+    });
+
+    let j2 = spawn(move || {
+        let r2 = y.load(Acquire);
+        x.store(1, Release);
+        r2
+    });
+
+    let r1 = j1.join().unwrap();
+    let r2 = j2.join().unwrap();
+
+    // 3 consistent outcomes: (0,0), (0,1), (1,0)
+    assert_ne!((r1, r2), (1, 1));
+}
+
+fn test_mixed_access() {
+    /*
+    int main() {
+      atomic_int x = 0;
+      {{{
+        x.store(1, mo_relaxed);
+      }}}
+
+      x.store(2, mo_relaxed);
+
+      {{{
+        r1 = x.load(mo_relaxed);
+      }}}
+
+      return 0;
+    }
+        */
+    let x = static_atomic(0);
+
+    spawn(move || {
+        x.store(1, Relaxed);
+    })
+    .join()
+    .unwrap();
+
+    x.store(2, Relaxed);
+
+    let r2 = spawn(move || x.load(Relaxed)).join().unwrap();
+
+    assert_eq!(r2, 2);
+}
+
+// The following two tests are taken from Repairing Sequential Consistency in C/C++11
+// by Lahav et al.
+// https://plv.mpi-sws.org/scfix/paper.pdf
+
+// Test case SB
+fn test_sc_store_buffering() {
+    let x = static_atomic(0);
+    let y = static_atomic(0);
+
+    let j1 = spawn(move || {
+        x.store(1, SeqCst);
+        y.load(SeqCst)
+    });
+
+    let j2 = spawn(move || {
+        y.store(1, SeqCst);
+        x.load(SeqCst)
+    });
+
+    let a = j1.join().unwrap();
+    let b = j2.join().unwrap();
+
+    assert_ne!((a, b), (0, 0));
+}
+
+fn test_single_thread() {
+    let x = AtomicI32::new(42);
+
+    assert_eq!(x.load(Relaxed), 42);
+
+    x.store(43, Relaxed);
+
+    assert_eq!(x.load(Relaxed), 43);
+}
+
+fn test_sync_through_rmw_and_fences() {
+    // Example from https://github.com/llvm/llvm-project/issues/56450#issuecomment-1183695905
+    #[no_mangle]
+    pub fn rdmw(storing: &AtomicI32, sync: &AtomicI32, loading: &AtomicI32) -> i32 {
+        storing.store(1, Relaxed);
+        fence(Release);
+        sync.fetch_add(0, Relaxed);
+        fence(Acquire);
+        loading.load(Relaxed)
+    }
+
+    let x = static_atomic(0);
+    let y = static_atomic(0);
+    let z = static_atomic(0);
+
+    // Since each thread is so short, we need to make sure that they truely run at the same time
+    // Otherwise t1 will finish before t2 even starts
+    let go = static_atomic_bool(false);
+
+    let t1 = spawn(move || {
+        while !go.load(Relaxed) {}
+        rdmw(y, x, z)
+    });
+
+    let t2 = spawn(move || {
+        while !go.load(Relaxed) {}
+        rdmw(z, x, y)
+    });
+
+    go.store(true, Relaxed);
+
+    let a = t1.join().unwrap();
+    let b = t2.join().unwrap();
+    assert_ne!((a, b), (0, 0));
+}
+
+// Test case by @SabrinaJewson
+// https://github.com/rust-lang/miri/issues/2301#issuecomment-1221502757
+// Demonstrating C++20 SC access changes
+fn test_iriw_sc_rlx() {
+    let x = static_atomic_bool(false);
+    let y = static_atomic_bool(false);
+
+    x.store(false, Relaxed);
+    y.store(false, Relaxed);
+
+    let a = spawn(move || x.store(true, Relaxed));
+    let b = spawn(move || y.store(true, Relaxed));
+    let c = spawn(move || {
+        while !x.load(SeqCst) {}
+        y.load(SeqCst)
+    });
+    let d = spawn(move || {
+        while !y.load(SeqCst) {}
+        x.load(SeqCst)
+    });
+
+    a.join().unwrap();
+    b.join().unwrap();
+    let c = c.join().unwrap();
+    let d = d.join().unwrap();
+
+    assert!(c || d);
+}
+
+pub fn main() {
+    for _ in 0..50 {
+        test_single_thread();
+        test_mixed_access();
+        test_load_buffering_acq_rel();
+        test_message_passing();
+        test_wrc();
+        test_corr();
+        test_sc_store_buffering();
+        test_sync_through_rmw_and_fences();
+        test_iriw_sc_rlx();
+    }
+}
diff --git a/src/tools/miri/tests/pass/adjacent-allocs.rs b/src/tools/miri/tests/pass/adjacent-allocs.rs
new file mode 100644
index 000000000000..0051c62121cd
--- /dev/null
+++ b/src/tools/miri/tests/pass/adjacent-allocs.rs
@@ -0,0 +1,63 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+fn ensure_allocs_can_be_adjacent() {
+    for _ in 0..512 {
+        let n = 0u64;
+        let ptr: *const u64 = &n;
+        let ptr2 = {
+            let m = 0u64;
+            &m as *const u64
+        };
+        if ptr.wrapping_add(1) == ptr2 {
+            return;
+        }
+    }
+    panic!("never saw adjacent stack variables?");
+}
+
+fn test1() {
+    // The slack between allocations is random.
+    // Loop a few times to hit the zero-slack case.
+    for _ in 0..512 {
+        let n = 0u64;
+        let ptr: *const u64 = &n;
+
+        // Allocate a new stack variable whose lifetime quickly ends.
+        // If there's a chance that &m == ptr.add(1), then an int-to-ptr cast of
+        // that value will have ambiguous provenance between n and m.
+        // See https://github.com/rust-lang/miri/issues/1866#issuecomment-985770125
+        {
+            let m = 0u64;
+            let _ = &m as *const u64;
+        }
+
+        let iptr = ptr as usize;
+        let zst = (iptr + 8) as *const ();
+        // This is a ZST ptr just at the end of `n`, so it should be valid to deref.
+        unsafe { *zst }
+    }
+}
+
+fn test2() {
+    fn foo() -> u64 {
+        0
+    }
+
+    for _ in 0..512 {
+        let n = 0u64;
+        let ptr: *const u64 = &n;
+        foo();
+        let iptr = ptr as usize;
+        unsafe {
+            let start = &*std::ptr::slice_from_raw_parts(iptr as *const (), 1);
+            let end = &*std::ptr::slice_from_raw_parts((iptr + 8) as *const (), 1);
+            assert_eq!(start.len(), end.len());
+        }
+    }
+}
+
+fn main() {
+    ensure_allocs_can_be_adjacent();
+    test1();
+    test2();
+}
diff --git a/src/tools/miri/tests/pass/align.rs b/src/tools/miri/tests/pass/align.rs
new file mode 100644
index 000000000000..997abd733922
--- /dev/null
+++ b/src/tools/miri/tests/pass/align.rs
@@ -0,0 +1,29 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+/// This manually makes sure that we have a pointer with the proper alignment.
+fn manual_alignment() {
+    let x = &mut [0u8; 3];
+    let base_addr = x as *mut _ as usize;
+    let base_addr_aligned = if base_addr % 2 == 0 { base_addr } else { base_addr + 1 };
+    let u16_ptr = base_addr_aligned as *mut u16;
+    unsafe {
+        *u16_ptr = 2;
+    }
+}
+
+/// Test standard library `align_to`.
+fn align_to() {
+    const LEN: usize = 128;
+    let buf = &[0u8; LEN];
+    let (l, m, r) = unsafe { buf.align_to::<i32>() };
+    assert!(m.len() * 4 >= LEN - 4);
+    assert!(l.len() + r.len() <= 4);
+}
+
+fn main() {
+    // Do this a couple times in a loop because it may work "by chance".
+    for _ in 0..10 {
+        manual_alignment();
+        align_to();
+    }
+}
diff --git a/src/tools/miri/tests/pass/align_offset_symbolic.rs b/src/tools/miri/tests/pass/align_offset_symbolic.rs
new file mode 100644
index 000000000000..b3e573383639
--- /dev/null
+++ b/src/tools/miri/tests/pass/align_offset_symbolic.rs
@@ -0,0 +1,105 @@
+//@compile-flags: -Zmiri-symbolic-alignment-check
+
+fn test_align_offset() {
+    let d = Box::new([0u32; 4]);
+    // Get u8 pointer to base
+    let raw = d.as_ptr() as *const u8;
+
+    assert_eq!(raw.align_offset(2), 0);
+    assert_eq!(raw.align_offset(4), 0);
+    assert_eq!(raw.align_offset(8), usize::MAX); // requested alignment higher than allocation alignment
+
+    assert_eq!(raw.wrapping_offset(1).align_offset(2), 1);
+    assert_eq!(raw.wrapping_offset(1).align_offset(4), 3);
+    assert_eq!(raw.wrapping_offset(1).align_offset(8), usize::MAX); // requested alignment higher than allocation alignment
+
+    assert_eq!(raw.wrapping_offset(2).align_offset(2), 0);
+    assert_eq!(raw.wrapping_offset(2).align_offset(4), 2);
+    assert_eq!(raw.wrapping_offset(2).align_offset(8), usize::MAX); // requested alignment higher than allocation alignment
+}
+
+fn test_align_to() {
+    const N: usize = 4;
+    let d = Box::new([0u32; N]);
+    // Get u8 slice covering the entire thing
+    let s = unsafe { std::slice::from_raw_parts(d.as_ptr() as *const u8, 4 * N) };
+    let raw = s.as_ptr();
+
+    {
+        let (l, m, r) = unsafe { s.align_to::<u32>() };
+        assert_eq!(l.len(), 0);
+        assert_eq!(r.len(), 0);
+        assert_eq!(m.len(), N);
+        assert_eq!(raw, m.as_ptr() as *const u8);
+    }
+
+    {
+        let (l, m, r) = unsafe { s[1..].align_to::<u32>() };
+        assert_eq!(l.len(), 3);
+        assert_eq!(m.len(), N - 1);
+        assert_eq!(r.len(), 0);
+        assert_eq!(raw.wrapping_offset(4), m.as_ptr() as *const u8);
+    }
+
+    {
+        let (l, m, r) = unsafe { s[..4 * N - 1].align_to::<u32>() };
+        assert_eq!(l.len(), 0);
+        assert_eq!(m.len(), N - 1);
+        assert_eq!(r.len(), 3);
+        assert_eq!(raw, m.as_ptr() as *const u8);
+    }
+
+    {
+        let (l, m, r) = unsafe { s[1..4 * N - 1].align_to::<u32>() };
+        assert_eq!(l.len(), 3);
+        assert_eq!(m.len(), N - 2);
+        assert_eq!(r.len(), 3);
+        assert_eq!(raw.wrapping_offset(4), m.as_ptr() as *const u8);
+    }
+
+    {
+        #[repr(align(8))]
+        struct Align8(u64);
+
+        let (l, m, r) = unsafe { s.align_to::<Align8>() }; // requested alignment higher than allocation alignment
+        assert_eq!(l.len(), 4 * N);
+        assert_eq!(r.len(), 0);
+        assert_eq!(m.len(), 0);
+    }
+}
+
+fn test_from_utf8() {
+    const N: usize = 10;
+    let vec = vec![0x4141414141414141u64; N];
+    let content = unsafe { std::slice::from_raw_parts(vec.as_ptr() as *const u8, 8 * N) };
+    println!("{:?}", std::str::from_utf8(content).unwrap());
+}
+
+fn test_u64_array() {
+    #[derive(Default)]
+    #[repr(align(8))]
+    struct AlignToU64<T>(T);
+
+    const BYTE_LEN: usize = std::mem::size_of::<[u64; 4]>();
+    type Data = AlignToU64<[u8; BYTE_LEN]>;
+
+    fn example(data: &Data) {
+        let (head, u64_arrays, tail) = unsafe { data.0.align_to::<[u64; 4]>() };
+
+        assert!(head.is_empty(), "buffer was not aligned for 64-bit numbers");
+        assert_eq!(u64_arrays.len(), 1, "buffer was not long enough");
+        assert!(tail.is_empty(), "buffer was too long");
+
+        let u64_array = &u64_arrays[0];
+        let _val = u64_array[0]; // make sure we can actually load this
+    }
+
+    example(&Data::default());
+}
+
+fn main() {
+    test_align_offset();
+    test_align_to();
+    test_from_utf8();
+    test_u64_array();
+}
diff --git a/src/tools/miri/tests/pass/align_offset_symbolic.stdout b/src/tools/miri/tests/pass/align_offset_symbolic.stdout
new file mode 100644
index 000000000000..66d439948159
--- /dev/null
+++ b/src/tools/miri/tests/pass/align_offset_symbolic.stdout
@@ -0,0 +1 @@
+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
diff --git a/src/tools/miri/tests/pass/arrays.rs b/src/tools/miri/tests/pass/arrays.rs
new file mode 100644
index 000000000000..9589ffa1724c
--- /dev/null
+++ b/src/tools/miri/tests/pass/arrays.rs
@@ -0,0 +1,78 @@
+use std::convert::TryFrom;
+
+fn empty_array() -> [u16; 0] {
+    []
+}
+
+fn mini_array() -> [u16; 1] {
+    [42]
+}
+
+fn big_array() -> [u16; 5] {
+    [5, 4, 3, 2, 1]
+}
+
+fn array_array() -> [[u8; 2]; 3] {
+    [[5, 4], [3, 2], [1, 0]]
+}
+
+fn index_unsafe() -> i32 {
+    let a = [0, 10, 20, 30];
+    unsafe { *a.get_unchecked(2) }
+}
+
+fn index() -> i32 {
+    let a = [0, 10, 20, 30];
+    a[2]
+}
+
+fn array_repeat() -> [u8; 8] {
+    [42; 8]
+}
+
+fn slice_index() -> u8 {
+    let arr: &[_] = &[101, 102, 103, 104, 105, 106];
+    arr[5]
+}
+
+fn from() {
+    const N: usize = 16;
+    type Array = [u8; N];
+    let array: Array = [0; N];
+    let slice: &[u8] = &array[..];
+
+    let result = <&Array>::try_from(slice);
+    assert_eq!(&array, result.unwrap());
+
+    let vec = Vec::from(array);
+    assert_eq!(vec.len(), N);
+}
+
+fn eq() {
+    const N: usize = 16;
+    type Array = [u8; N];
+    let array1: Array = [0; N];
+    let array2: Array = [0; N];
+    let array3: Array = [1; N];
+    assert_eq!(array1, array2);
+    assert_ne!(array1, array3);
+}
+
+fn debug() {
+    let array = [0u8, 42, 13, 71];
+    println!("{:?}", array);
+}
+
+fn main() {
+    assert_eq!(empty_array(), []);
+    assert_eq!(index_unsafe(), 20);
+    assert_eq!(index(), 20);
+    assert_eq!(slice_index(), 106);
+    assert_eq!(big_array(), [5, 4, 3, 2, 1]);
+    assert_eq!(array_array(), [[5, 4], [3, 2], [1, 0]]);
+    assert_eq!(array_repeat(), [42; 8]);
+    assert_eq!(mini_array(), [42]);
+    from();
+    eq();
+    debug();
+}
diff --git a/src/tools/miri/tests/pass/arrays.stdout b/src/tools/miri/tests/pass/arrays.stdout
new file mode 100644
index 000000000000..6c3cefadf803
--- /dev/null
+++ b/src/tools/miri/tests/pass/arrays.stdout
@@ -0,0 +1 @@
+[0, 42, 13, 71]
diff --git a/src/tools/miri/tests/pass/associated-const.rs b/src/tools/miri/tests/pass/associated-const.rs
new file mode 100644
index 000000000000..2ff08ffc4bf6
--- /dev/null
+++ b/src/tools/miri/tests/pass/associated-const.rs
@@ -0,0 +1,11 @@
+trait Foo {
+    const ID: i32;
+}
+
+impl Foo for i32 {
+    const ID: i32 = 1;
+}
+
+fn main() {
+    assert_eq!(1, <i32 as Foo>::ID);
+}
diff --git a/src/tools/miri/tests/pass/assume_bug.rs b/src/tools/miri/tests/pass/assume_bug.rs
new file mode 100644
index 000000000000..e14f875c022e
--- /dev/null
+++ b/src/tools/miri/tests/pass/assume_bug.rs
@@ -0,0 +1,3 @@
+fn main() {
+    vec![()].into_iter();
+}
diff --git a/src/tools/miri/tests/pass/async-fn.rs b/src/tools/miri/tests/pass/async-fn.rs
new file mode 100644
index 000000000000..1d5d9a27cc8a
--- /dev/null
+++ b/src/tools/miri/tests/pass/async-fn.rs
@@ -0,0 +1,90 @@
+#![feature(never_type)]
+
+use std::future::Future;
+
+// See if we can run a basic `async fn`
+pub async fn foo(x: &u32, y: u32) -> u32 {
+    let y = &y;
+    let z = 9;
+    let z = &z;
+    let y = async { *y + *z }.await;
+    let a = 10;
+    let a = &a;
+    *x + y + *a
+}
+
+async fn add(x: u32, y: u32) -> u32 {
+    let a = async { x + y };
+    a.await
+}
+
+async fn build_aggregate(a: u32, b: u32, c: u32, d: u32) -> u32 {
+    let x = (add(a, b).await, add(c, d).await);
+    x.0 + x.1
+}
+
+enum Never {}
+fn never() -> Never {
+    panic!()
+}
+
+async fn includes_never(crash: bool, x: u32) -> u32 {
+    let result = async { x * x }.await;
+    if !crash {
+        return result;
+    }
+    #[allow(unused)]
+    let bad = never();
+    result *= async { x + x }.await;
+    drop(bad);
+    result
+}
+
+async fn partial_init(x: u32) -> u32 {
+    #[allow(unreachable_code)]
+    let _x: (String, !) = (String::new(), return async { x + x }.await);
+}
+
+async fn read_exact(_from: &mut &[u8], _to: &mut [u8]) -> Option<()> {
+    Some(())
+}
+
+async fn hello_world() {
+    let data = [0u8; 1];
+    let mut reader = &data[..];
+
+    let mut marker = [0u8; 1];
+    read_exact(&mut reader, &mut marker).await.unwrap();
+}
+
+fn run_fut<T>(fut: impl Future<Output = T>) -> T {
+    use std::sync::Arc;
+    use std::task::{Context, Poll, Wake, Waker};
+
+    struct MyWaker;
+    impl Wake for MyWaker {
+        fn wake(self: Arc<Self>) {
+            unimplemented!()
+        }
+    }
+
+    let waker = Waker::from(Arc::new(MyWaker));
+    let mut context = Context::from_waker(&waker);
+
+    let mut pinned = Box::pin(fut);
+    loop {
+        match pinned.as_mut().poll(&mut context) {
+            Poll::Pending => continue,
+            Poll::Ready(v) => return v,
+        }
+    }
+}
+
+fn main() {
+    let x = 5;
+    assert_eq!(run_fut(foo(&x, 7)), 31);
+    assert_eq!(run_fut(build_aggregate(1, 2, 3, 4)), 10);
+    assert_eq!(run_fut(includes_never(false, 4)), 16);
+    assert_eq!(run_fut(partial_init(4)), 8);
+    run_fut(hello_world());
+}
diff --git a/src/tools/miri/tests/pass/atomic-compare-exchange-weak-never-fail.rs b/src/tools/miri/tests/pass/atomic-compare-exchange-weak-never-fail.rs
new file mode 100644
index 000000000000..8d3d71869f42
--- /dev/null
+++ b/src/tools/miri/tests/pass/atomic-compare-exchange-weak-never-fail.rs
@@ -0,0 +1,17 @@
+//@compile-flags: -Zmiri-compare-exchange-weak-failure-rate=0.0
+use std::sync::atomic::{AtomicBool, Ordering::*};
+
+// Ensure that compare_exchange_weak never fails.
+fn main() {
+    let atomic = AtomicBool::new(false);
+    let tries = 100;
+    for _ in 0..tries {
+        let cur = atomic.load(Relaxed);
+        // Try (weakly) to flip the flag.
+        if atomic.compare_exchange_weak(cur, !cur, Relaxed, Relaxed).is_err() {
+            // We failed. Avoid panic machinery as that uses atomics/locks.
+            eprintln!("compare_exchange_weak failed");
+            std::process::abort();
+        }
+    }
+}
diff --git a/src/tools/miri/tests/pass/atomic.rs b/src/tools/miri/tests/pass/atomic.rs
new file mode 100644
index 000000000000..e3d80a78916f
--- /dev/null
+++ b/src/tools/miri/tests/pass/atomic.rs
@@ -0,0 +1,191 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(strict_provenance, strict_provenance_atomic_ptr)]
+use std::sync::atomic::{
+    compiler_fence, fence, AtomicBool, AtomicIsize, AtomicPtr, AtomicU64, Ordering::*,
+};
+
+fn main() {
+    atomic_bool();
+    atomic_all_ops();
+    atomic_u64();
+    atomic_fences();
+    atomic_ptr();
+    weak_sometimes_fails();
+}
+
+fn atomic_bool() {
+    static mut ATOMIC: AtomicBool = AtomicBool::new(false);
+
+    unsafe {
+        assert_eq!(*ATOMIC.get_mut(), false);
+        ATOMIC.store(true, SeqCst);
+        assert_eq!(*ATOMIC.get_mut(), true);
+        ATOMIC.fetch_or(false, SeqCst);
+        assert_eq!(*ATOMIC.get_mut(), true);
+        ATOMIC.fetch_and(false, SeqCst);
+        assert_eq!(*ATOMIC.get_mut(), false);
+        ATOMIC.fetch_nand(true, SeqCst);
+        assert_eq!(*ATOMIC.get_mut(), true);
+        ATOMIC.fetch_xor(true, SeqCst);
+        assert_eq!(*ATOMIC.get_mut(), false);
+    }
+}
+
+// There isn't a trait to use to make this generic, so just use a macro
+macro_rules! compare_exchange_weak_loop {
+    ($atom:expr, $from:expr, $to:expr, $succ_order:expr, $fail_order:expr) => {
+        loop {
+            match $atom.compare_exchange_weak($from, $to, $succ_order, $fail_order) {
+                Ok(n) => {
+                    assert_eq!(n, $from);
+                    break;
+                }
+                Err(n) => assert_eq!(n, $from),
+            }
+        }
+    };
+}
+
+/// Make sure we can handle all the intrinsics
+fn atomic_all_ops() {
+    static ATOMIC: AtomicIsize = AtomicIsize::new(0);
+    static ATOMIC_UNSIGNED: AtomicU64 = AtomicU64::new(0);
+
+    let load_orders = [Relaxed, Acquire, SeqCst];
+    let stored_orders = [Relaxed, Release, SeqCst];
+    let rmw_orders = [Relaxed, Release, Acquire, AcqRel, SeqCst];
+
+    // loads
+    for o in load_orders {
+        ATOMIC.load(o);
+    }
+
+    // stores
+    for o in stored_orders {
+        ATOMIC.store(1, o);
+    }
+
+    // most RMWs
+    for o in rmw_orders {
+        ATOMIC.swap(0, o);
+        ATOMIC.fetch_or(0, o);
+        ATOMIC.fetch_xor(0, o);
+        ATOMIC.fetch_and(0, o);
+        ATOMIC.fetch_nand(0, o);
+        ATOMIC.fetch_add(0, o);
+        ATOMIC.fetch_sub(0, o);
+        ATOMIC.fetch_min(0, o);
+        ATOMIC.fetch_max(0, o);
+        ATOMIC_UNSIGNED.fetch_min(0, o);
+        ATOMIC_UNSIGNED.fetch_max(0, o);
+    }
+
+    // RMWs with separate failure ordering
+    for o1 in rmw_orders {
+        for o2 in load_orders {
+            let _res = ATOMIC.compare_exchange(0, 0, o1, o2);
+            let _res = ATOMIC.compare_exchange_weak(0, 0, o1, o2);
+        }
+    }
+}
+
+fn atomic_u64() {
+    static ATOMIC: AtomicU64 = AtomicU64::new(0);
+
+    ATOMIC.store(1, SeqCst);
+    assert_eq!(ATOMIC.compare_exchange(0, 0x100, AcqRel, Acquire), Err(1));
+    assert_eq!(ATOMIC.compare_exchange(0, 1, Release, Relaxed), Err(1));
+    assert_eq!(ATOMIC.compare_exchange(1, 0, AcqRel, Relaxed), Ok(1));
+    assert_eq!(ATOMIC.compare_exchange(0, 1, Relaxed, Relaxed), Ok(0));
+    compare_exchange_weak_loop!(ATOMIC, 1, 0x100, AcqRel, Acquire);
+    assert_eq!(ATOMIC.compare_exchange_weak(0, 2, Acquire, Relaxed), Err(0x100));
+    assert_eq!(ATOMIC.compare_exchange_weak(0, 1, Release, Relaxed), Err(0x100));
+    assert_eq!(ATOMIC.load(Relaxed), 0x100);
+
+    assert_eq!(ATOMIC.fetch_max(0x10, SeqCst), 0x100);
+    assert_eq!(ATOMIC.fetch_max(0x100, SeqCst), 0x100);
+    assert_eq!(ATOMIC.fetch_max(0x1000, SeqCst), 0x100);
+    assert_eq!(ATOMIC.fetch_max(0x1000, SeqCst), 0x1000);
+    assert_eq!(ATOMIC.fetch_max(0x2000, SeqCst), 0x1000);
+    assert_eq!(ATOMIC.fetch_max(0x2000, SeqCst), 0x2000);
+
+    assert_eq!(ATOMIC.fetch_min(0x2000, SeqCst), 0x2000);
+    assert_eq!(ATOMIC.fetch_min(0x2000, SeqCst), 0x2000);
+    assert_eq!(ATOMIC.fetch_min(0x1000, SeqCst), 0x2000);
+    assert_eq!(ATOMIC.fetch_min(0x1000, SeqCst), 0x1000);
+    assert_eq!(ATOMIC.fetch_min(0x100, SeqCst), 0x1000);
+    assert_eq!(ATOMIC.fetch_min(0x10, SeqCst), 0x100);
+}
+
+fn atomic_fences() {
+    fence(SeqCst);
+    fence(Release);
+    fence(Acquire);
+    fence(AcqRel);
+    compiler_fence(SeqCst);
+    compiler_fence(Release);
+    compiler_fence(Acquire);
+    compiler_fence(AcqRel);
+}
+
+fn atomic_ptr() {
+    use std::ptr;
+    let array: Vec<i32> = (0..100).into_iter().collect(); // a target to point to, to test provenance things
+    let x = array.as_ptr() as *mut i32;
+
+    let ptr = AtomicPtr::<i32>::new(ptr::null_mut());
+    assert!(ptr.load(Relaxed).addr() == 0);
+    ptr.store(ptr::invalid_mut(13), SeqCst);
+    assert!(ptr.swap(x, Relaxed).addr() == 13);
+    unsafe { assert!(*ptr.load(Acquire) == 0) };
+
+    // comparison ignores provenance
+    assert_eq!(
+        ptr.compare_exchange(
+            (&mut 0 as *mut i32).with_addr(x.addr()),
+            ptr::invalid_mut(0),
+            SeqCst,
+            SeqCst
+        )
+        .unwrap()
+        .addr(),
+        x.addr(),
+    );
+    assert_eq!(
+        ptr.compare_exchange(
+            (&mut 0 as *mut i32).with_addr(x.addr()),
+            ptr::invalid_mut(0),
+            SeqCst,
+            SeqCst
+        )
+        .unwrap_err()
+        .addr(),
+        0,
+    );
+    ptr.store(x, Relaxed);
+
+    assert_eq!(ptr.fetch_ptr_add(13, AcqRel).addr(), x.addr());
+    unsafe { assert_eq!(*ptr.load(SeqCst), 13) }; // points to index 13 now
+    assert_eq!(ptr.fetch_ptr_sub(4, AcqRel).addr(), x.addr() + 13 * 4);
+    unsafe { assert_eq!(*ptr.load(SeqCst), 9) };
+    assert_eq!(ptr.fetch_or(3, AcqRel).addr(), x.addr() + 9 * 4); // ptr is 4-aligned, so set the last 2 bits
+    assert_eq!(ptr.fetch_and(!3, AcqRel).addr(), (x.addr() + 9 * 4) | 3); // and unset them again
+    unsafe { assert_eq!(*ptr.load(SeqCst), 9) };
+    assert_eq!(ptr.fetch_xor(0xdeadbeef, AcqRel).addr(), x.addr() + 9 * 4);
+    assert_eq!(ptr.fetch_xor(0xdeadbeef, AcqRel).addr(), (x.addr() + 9 * 4) ^ 0xdeadbeef);
+    unsafe { assert_eq!(*ptr.load(SeqCst), 9) }; // after XORing twice with the same thing, we get our ptr back
+}
+
+fn weak_sometimes_fails() {
+    let atomic = AtomicBool::new(false);
+    let tries = 100;
+    for _ in 0..tries {
+        let cur = atomic.load(Relaxed);
+        // Try (weakly) to flip the flag.
+        if atomic.compare_exchange_weak(cur, !cur, Relaxed, Relaxed).is_err() {
+            // We failed, so return and skip the panic.
+            return;
+        }
+    }
+    panic!("compare_exchange_weak succeeded {} tries in a row", tries);
+}
diff --git a/src/tools/miri/tests/pass/available-parallelism.rs b/src/tools/miri/tests/pass/available-parallelism.rs
new file mode 100644
index 000000000000..eb4d09b1f549
--- /dev/null
+++ b/src/tools/miri/tests/pass/available-parallelism.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert_eq!(std::thread::available_parallelism().unwrap().get(), 1);
+}
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.rs b/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.rs
new file mode 100644
index 000000000000..5cd12959ca40
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.rs
@@ -0,0 +1,67 @@
+//@normalize-stderr-test: "::<.*>" -> ""
+
+#[inline(never)]
+fn func_a() -> Box<[*mut ()]> {
+    func_b::<u8>()
+}
+#[inline(never)]
+fn func_b<T>() -> Box<[*mut ()]> {
+    func_c()
+}
+
+macro_rules! invoke_func_d {
+    () => {
+        func_d()
+    };
+}
+
+#[inline(never)]
+fn func_c() -> Box<[*mut ()]> {
+    invoke_func_d!()
+}
+#[inline(never)]
+fn func_d() -> Box<[*mut ()]> {
+    unsafe { miri_get_backtrace(0) }
+}
+
+fn main() {
+    let mut seen_main = false;
+    let frames = func_a();
+    for frame in frames.into_iter() {
+        let miri_frame = unsafe { miri_resolve_frame(*frame, 0) };
+        let name = String::from_utf8(miri_frame.name.into()).unwrap();
+        let filename = String::from_utf8(miri_frame.filename.into()).unwrap();
+
+        if name == "func_a" {
+            assert_eq!(func_a as *mut (), miri_frame.fn_ptr);
+        }
+
+        // Print every frame to stderr.
+        let out = format!("{}:{}:{} ({})", filename, miri_frame.lineno, miri_frame.colno, name);
+        eprintln!("{}", out);
+        // Print the 'main' frame (and everything before it) to stdout, skipping
+        // the printing of internal (and possibly fragile) libstd frames.
+        if !seen_main {
+            println!("{}", out);
+            seen_main = name == "main";
+        }
+    }
+}
+
+// This goes at the bottom of the file so that we can change it
+// without disturbing line numbers of the functions in the backtrace.
+
+extern "Rust" {
+    fn miri_get_backtrace(flags: u64) -> Box<[*mut ()]>;
+    fn miri_resolve_frame(ptr: *mut (), flags: u64) -> MiriFrame;
+}
+
+#[derive(Debug)]
+#[repr(C)]
+struct MiriFrame {
+    name: Box<[u8]>,
+    filename: Box<[u8]>,
+    lineno: u32,
+    colno: u32,
+    fn_ptr: *mut (),
+}
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.stderr b/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.stderr
new file mode 100644
index 000000000000..ee556b3e4a05
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.stderr
@@ -0,0 +1,5 @@
+$DIR/backtrace-api-v0.rs:LL:CC (func_d)
+$DIR/backtrace-api-v0.rs:LL:CC (func_c)
+$DIR/backtrace-api-v0.rs:LL:CC (func_b)
+$DIR/backtrace-api-v0.rs:LL:CC (func_a)
+$DIR/backtrace-api-v0.rs:LL:CC RUSTLIB/core/src/ops/function.rs:LL:CC (<fn() as std::ops::FnOnce<()>>::call_once - RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC (std::sys_common::backtrace::__rust_begin_short_backtrace)
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.stdout b/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.stdout
new file mode 100644
index 000000000000..2fe31dd0e6ba
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-api-v0.stdout
@@ -0,0 +1,5 @@
+$DIR/backtrace-api-v0.rs:24:14 (func_d)
+$DIR/backtrace-api-v0.rs:20:5 (func_c)
+$DIR/backtrace-api-v0.rs:9:5 (func_b)
+$DIR/backtrace-api-v0.rs:5:5 (func_a)
+$DIR/backtrace-api-v0.rs:29:18 (main)
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.rs b/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.rs
new file mode 100644
index 000000000000..1e35574b39b6
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.rs
@@ -0,0 +1,82 @@
+//@normalize-stderr-test: "::<.*>" -> ""
+
+#[inline(never)]
+fn func_a() -> Box<[*mut ()]> {
+    func_b::<u8>()
+}
+#[inline(never)]
+fn func_b<T>() -> Box<[*mut ()]> {
+    func_c()
+}
+
+macro_rules! invoke_func_d {
+    () => {
+        func_d()
+    };
+}
+
+#[inline(never)]
+fn func_c() -> Box<[*mut ()]> {
+    invoke_func_d!()
+}
+#[inline(never)]
+fn func_d() -> Box<[*mut ()]> {
+    unsafe {
+        let count = miri_backtrace_size(0);
+        let mut buf = vec![std::ptr::null_mut(); count];
+        miri_get_backtrace(1, buf.as_mut_ptr());
+        buf.into()
+    }
+}
+
+fn main() {
+    let mut seen_main = false;
+    let frames = func_a();
+    for frame in frames.into_iter() {
+        let miri_frame = unsafe { miri_resolve_frame(*frame, 1) };
+
+        let mut name = vec![0; miri_frame.name_len];
+        let mut filename = vec![0; miri_frame.filename_len];
+
+        unsafe {
+            miri_resolve_frame_names(*frame, 0, name.as_mut_ptr(), filename.as_mut_ptr());
+        }
+
+        let name = String::from_utf8(name).unwrap();
+        let filename = String::from_utf8(filename).unwrap();
+
+        if name == "func_a" {
+            assert_eq!(func_a as *mut (), miri_frame.fn_ptr);
+        }
+
+        // Print every frame to stderr.
+        let out = format!("{}:{}:{} ({})", filename, miri_frame.lineno, miri_frame.colno, name);
+        eprintln!("{}", out);
+        // Print the 'main' frame (and everything before it) to stdout, skipping
+        // the printing of internal (and possibly fragile) libstd frames.
+        if !seen_main {
+            println!("{}", out);
+            seen_main = name == "main";
+        }
+    }
+}
+
+// This goes at the bottom of the file so that we can change it
+// without disturbing line numbers of the functions in the backtrace.
+
+extern "Rust" {
+    fn miri_backtrace_size(flags: u64) -> usize;
+    fn miri_get_backtrace(flags: u64, buf: *mut *mut ());
+    fn miri_resolve_frame(ptr: *mut (), flags: u64) -> MiriFrame;
+    fn miri_resolve_frame_names(ptr: *mut (), flags: u64, name_buf: *mut u8, filename_buf: *mut u8);
+}
+
+#[derive(Debug)]
+#[repr(C)]
+struct MiriFrame {
+    name_len: usize,
+    filename_len: usize,
+    lineno: u32,
+    colno: u32,
+    fn_ptr: *mut (),
+}
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.stderr b/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.stderr
new file mode 100644
index 000000000000..7dc281af31dd
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.stderr
@@ -0,0 +1,5 @@
+$DIR/backtrace-api-v1.rs:LL:CC (func_d)
+$DIR/backtrace-api-v1.rs:LL:CC (func_c)
+$DIR/backtrace-api-v1.rs:LL:CC (func_b)
+$DIR/backtrace-api-v1.rs:LL:CC (func_a)
+$DIR/backtrace-api-v1.rs:LL:CC RUSTLIB/core/src/ops/function.rs:LL:CC (<fn() as std::ops::FnOnce<()>>::call_once - RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC (std::sys_common::backtrace::__rust_begin_short_backtrace)
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.stdout b/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.stdout
new file mode 100644
index 000000000000..0d2ae3b516a8
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-api-v1.stdout
@@ -0,0 +1,5 @@
+$DIR/backtrace-api-v1.rs:27:9 (func_d)
+$DIR/backtrace-api-v1.rs:20:5 (func_c)
+$DIR/backtrace-api-v1.rs:9:5 (func_b)
+$DIR/backtrace-api-v1.rs:5:5 (func_a)
+$DIR/backtrace-api-v1.rs:34:18 (main)
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-global-alloc.rs b/src/tools/miri/tests/pass/backtrace/backtrace-global-alloc.rs
new file mode 100644
index 000000000000..6660e5bb57c0
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-global-alloc.rs
@@ -0,0 +1,12 @@
+//@compile-flags: -Zmiri-disable-isolation
+//@rustc-env: RUST_BACKTRACE=1
+
+use std::alloc::System;
+use std::backtrace::Backtrace;
+
+#[global_allocator]
+static GLOBAL_ALLOCATOR: System = System;
+
+fn main() {
+    eprint!("{}", Backtrace::capture());
+}
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-global-alloc.stderr b/src/tools/miri/tests/pass/backtrace/backtrace-global-alloc.stderr
new file mode 100644
index 000000000000..c48061d64d08
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-global-alloc.stderr
@@ -0,0 +1,28 @@
+   0: main
+ at $DIR/backtrace-global-alloc.rs:LL:CC
+   1: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+   2: std::sys_common::backtrace::__rust_begin_short_backtrace
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   3: std::rt::lang_start::{closure#0}
+ at RUSTLIB/std/src/rt.rs:LL:CC
+   4: std::ops::function::impls::call_once
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+   5: std::panicking::r#try::do_call
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+   6: std::panicking::r#try
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+   7: std::panic::catch_unwind
+ at RUSTLIB/std/src/panic.rs:LL:CC
+   8: std::rt::lang_start_internal::{closure#2}
+ at RUSTLIB/std/src/rt.rs:LL:CC
+   9: std::panicking::r#try::do_call
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  10: std::panicking::r#try
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  11: std::panic::catch_unwind
+ at RUSTLIB/std/src/panic.rs:LL:CC
+  12: std::rt::lang_start_internal
+ at RUSTLIB/std/src/rt.rs:LL:CC
+  13: std::rt::lang_start
+ at RUSTLIB/std/src/rt.rs:LL:CC
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-std.rs b/src/tools/miri/tests/pass/backtrace/backtrace-std.rs
new file mode 100644
index 000000000000..b2a5ac180298
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-std.rs
@@ -0,0 +1,32 @@
+//@compile-flags: -Zmiri-disable-isolation
+//@rustc-env: RUST_BACKTRACE=1
+
+use std::backtrace::Backtrace;
+
+#[inline(never)]
+fn func_a() -> Backtrace {
+    func_b::<u8>()
+}
+#[inline(never)]
+fn func_b<T>() -> Backtrace {
+    func_c()
+}
+
+macro_rules! invoke_func_d {
+    () => {
+        func_d()
+    };
+}
+
+#[inline(never)]
+fn func_c() -> Backtrace {
+    invoke_func_d!()
+}
+#[inline(never)]
+fn func_d() -> Backtrace {
+    Backtrace::capture()
+}
+
+fn main() {
+    eprint!("{}", func_a());
+}
diff --git a/src/tools/miri/tests/pass/backtrace/backtrace-std.stderr b/src/tools/miri/tests/pass/backtrace/backtrace-std.stderr
new file mode 100644
index 000000000000..4596cadb958d
--- /dev/null
+++ b/src/tools/miri/tests/pass/backtrace/backtrace-std.stderr
@@ -0,0 +1,36 @@
+   0: func_d
+ at $DIR/backtrace-std.rs:LL:CC
+   1: func_c
+ at $DIR/backtrace-std.rs:LL:CC
+   2: func_b
+ at $DIR/backtrace-std.rs:LL:CC
+   3: func_a
+ at $DIR/backtrace-std.rs:LL:CC
+   4: main
+ at $DIR/backtrace-std.rs:LL:CC
+   5: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+   6: std::sys_common::backtrace::__rust_begin_short_backtrace
+ at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   7: std::rt::lang_start::{closure#0}
+ at RUSTLIB/std/src/rt.rs:LL:CC
+   8: std::ops::function::impls::call_once
+ at RUSTLIB/core/src/ops/function.rs:LL:CC
+   9: std::panicking::r#try::do_call
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  10: std::panicking::r#try
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  11: std::panic::catch_unwind
+ at RUSTLIB/std/src/panic.rs:LL:CC
+  12: std::rt::lang_start_internal::{closure#2}
+ at RUSTLIB/std/src/rt.rs:LL:CC
+  13: std::panicking::r#try::do_call
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  14: std::panicking::r#try
+ at RUSTLIB/std/src/panicking.rs:LL:CC
+  15: std::panic::catch_unwind
+ at RUSTLIB/std/src/panic.rs:LL:CC
+  16: std::rt::lang_start_internal
+ at RUSTLIB/std/src/rt.rs:LL:CC
+  17: std::rt::lang_start
+ at RUSTLIB/std/src/rt.rs:LL:CC
diff --git a/src/tools/miri/tests/pass/bad_substs.rs b/src/tools/miri/tests/pass/bad_substs.rs
new file mode 100644
index 000000000000..d8da2de5d6df
--- /dev/null
+++ b/src/tools/miri/tests/pass/bad_substs.rs
@@ -0,0 +1,4 @@
+fn main() {
+    let f: fn(i32) -> Option<i32> = Some::<i32>;
+    f(42);
+}
diff --git a/src/tools/miri/tests/pass/binary-heap.rs b/src/tools/miri/tests/pass/binary-heap.rs
new file mode 100644
index 000000000000..278038d8ad32
--- /dev/null
+++ b/src/tools/miri/tests/pass/binary-heap.rs
@@ -0,0 +1,37 @@
+use std::collections::BinaryHeap;
+use std::iter::Iterator;
+
+fn zero_sized_push() {
+    const N: usize = 8;
+
+    for len in 0..N {
+        let mut tester = BinaryHeap::with_capacity(len);
+        assert_eq!(tester.len(), 0);
+        assert!(tester.capacity() >= len);
+        for _ in 0..len {
+            tester.push(());
+        }
+        assert_eq!(tester.len(), len);
+        assert_eq!(tester.iter().count(), len);
+        tester.clear();
+    }
+}
+
+fn drain() {
+    let mut heap = (0..128i32).collect::<BinaryHeap<_>>();
+
+    assert!(!heap.is_empty());
+
+    let mut sum = 0;
+    for x in heap.drain() {
+        sum += x;
+    }
+    assert_eq!(sum, 127 * 128 / 2);
+
+    assert!(heap.is_empty());
+}
+
+fn main() {
+    zero_sized_push();
+    drain();
+}
diff --git a/src/tools/miri/tests/pass/binops.rs b/src/tools/miri/tests/pass/binops.rs
new file mode 100644
index 000000000000..0988d7ccc4c6
--- /dev/null
+++ b/src/tools/miri/tests/pass/binops.rs
@@ -0,0 +1,78 @@
+// Binop corner cases
+
+fn test_nil() {
+    assert_eq!((), ());
+    assert!((!(() != ())));
+    assert!((!(() < ())));
+    assert!((() <= ()));
+    assert!((!(() > ())));
+    assert!((() >= ()));
+}
+
+fn test_bool() {
+    assert!((!(true < false)));
+    assert!((!(true <= false)));
+    assert!((true > false));
+    assert!((true >= false));
+
+    assert!((false < true));
+    assert!((false <= true));
+    assert!((!(false > true)));
+    assert!((!(false >= true)));
+
+    // Bools support bitwise binops
+    assert_eq!(false & false, false);
+    assert_eq!(true & false, false);
+    assert_eq!(true & true, true);
+    assert_eq!(false | false, false);
+    assert_eq!(true | false, true);
+    assert_eq!(true | true, true);
+    assert_eq!(false ^ false, false);
+    assert_eq!(true ^ false, true);
+    assert_eq!(true ^ true, false);
+}
+
+fn test_ptr() {
+    unsafe {
+        let p1: *const u8 = ::std::mem::transmute(0_usize);
+        let p2: *const u8 = ::std::mem::transmute(0_usize);
+        let p3: *const u8 = ::std::mem::transmute(1_usize);
+
+        assert_eq!(p1, p2);
+        assert!(p1 != p3);
+        assert!(p1 < p3);
+        assert!(p1 <= p3);
+        assert!(p3 > p1);
+        assert!(p3 >= p3);
+        assert!(p1 <= p2);
+        assert!(p1 >= p2);
+    }
+}
+
+#[derive(PartialEq, Debug)]
+struct P {
+    x: isize,
+    y: isize,
+}
+
+fn p(x: isize, y: isize) -> P {
+    P { x: x, y: y }
+}
+
+fn test_class() {
+    let q = p(1, 2);
+    let mut r = p(1, 2);
+
+    assert_eq!(q, r);
+    r.y = 17;
+    assert!((r.y != q.y));
+    assert_eq!(r.y, 17);
+    assert!((q != r));
+}
+
+pub fn main() {
+    test_nil();
+    test_bool();
+    test_ptr();
+    test_class();
+}
diff --git a/src/tools/miri/tests/pass/bools.rs b/src/tools/miri/tests/pass/bools.rs
new file mode 100644
index 000000000000..30fc14704d9d
--- /dev/null
+++ b/src/tools/miri/tests/pass/bools.rs
@@ -0,0 +1,29 @@
+fn boolean() -> bool {
+    true
+}
+
+fn if_false() -> i64 {
+    let c = false;
+    if c { 1 } else { 0 }
+}
+
+fn if_true() -> i64 {
+    let c = true;
+    if c { 1 } else { 0 }
+}
+
+fn match_bool() -> i16 {
+    let b = true;
+    match b {
+        true => 1,
+        _ => 0,
+    }
+}
+
+fn main() {
+    assert!(boolean());
+    assert_eq!(if_false(), 0);
+    assert_eq!(if_true(), 1);
+    assert_eq!(match_bool(), 1);
+    assert_eq!(true == true, true);
+}
diff --git a/src/tools/miri/tests/pass/box-custom-alloc.rs b/src/tools/miri/tests/pass/box-custom-alloc.rs
new file mode 100644
index 000000000000..ef432a86d460
--- /dev/null
+++ b/src/tools/miri/tests/pass/box-custom-alloc.rs
@@ -0,0 +1,87 @@
+#![allow(incomplete_features)] // for trait upcasting
+#![feature(allocator_api, trait_upcasting)]
+
+use std::alloc::Layout;
+use std::alloc::{AllocError, Allocator};
+use std::cell::Cell;
+use std::mem::MaybeUninit;
+use std::ptr::{self, NonNull};
+
+struct OnceAlloc<'a> {
+    space: Cell<&'a mut [MaybeUninit<u8>]>,
+}
+
+unsafe impl<'shared, 'a: 'shared> Allocator for &'shared OnceAlloc<'a> {
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        let space = self.space.replace(&mut []);
+
+        let (ptr, len) = (space.as_mut_ptr(), space.len());
+
+        if ptr.align_offset(layout.align()) != 0 || len < layout.size() {
+            return Err(AllocError);
+        }
+
+        let slice_ptr = ptr::slice_from_raw_parts_mut(ptr as *mut u8, len);
+        unsafe { Ok(NonNull::new_unchecked(slice_ptr)) }
+    }
+
+    unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout) {}
+}
+
+trait MyTrait {
+    fn hello(&self) -> u8;
+}
+
+impl MyTrait for [u8; 1] {
+    fn hello(&self) -> u8 {
+        self[0]
+    }
+}
+
+trait TheTrait: MyTrait {}
+
+impl TheTrait for [u8; 1] {}
+
+/// `Box<T, G>` is a `ScalarPair` where the 2nd component is the allocator.
+fn test1() {
+    let mut space = vec![MaybeUninit::new(0); 1];
+    let once_alloc = OnceAlloc { space: Cell::new(&mut space[..]) };
+
+    let boxed = Box::new_in([42u8; 1], &once_alloc);
+    let _val = *boxed;
+    let with_dyn: Box<dyn TheTrait, &OnceAlloc> = boxed;
+    assert_eq!(42, with_dyn.hello());
+    let with_dyn: Box<dyn MyTrait, &OnceAlloc> = with_dyn; // upcast
+    assert_eq!(42, with_dyn.hello());
+}
+
+// Make the allocator itself so big that the Box is not even a ScalarPair any more.
+struct OnceAllocRef<'s, 'a>(&'s OnceAlloc<'a>, u64);
+
+unsafe impl<'shared, 'a: 'shared> Allocator for OnceAllocRef<'shared, 'a> {
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        self.0.allocate(layout)
+    }
+
+    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+        self.0.deallocate(ptr, layout)
+    }
+}
+
+/// `Box<T, G>` is an `Aggregate`.
+fn test2() {
+    let mut space = vec![MaybeUninit::new(0); 1];
+    let once_alloc = OnceAlloc { space: Cell::new(&mut space[..]) };
+
+    let boxed = Box::new_in([42u8; 1], OnceAllocRef(&once_alloc, 0));
+    let _val = *boxed;
+    let with_dyn: Box<dyn TheTrait, OnceAllocRef> = boxed;
+    assert_eq!(42, with_dyn.hello());
+    let with_dyn: Box<dyn MyTrait, OnceAllocRef> = with_dyn; // upcast
+    assert_eq!(42, with_dyn.hello());
+}
+
+fn main() {
+    test1();
+    test2();
+}
diff --git a/src/tools/miri/tests/pass/box.rs b/src/tools/miri/tests/pass/box.rs
new file mode 100644
index 000000000000..7bbe7be516b9
--- /dev/null
+++ b/src/tools/miri/tests/pass/box.rs
@@ -0,0 +1,59 @@
+#![feature(ptr_internals)]
+
+fn main() {
+    into_raw();
+    into_unique();
+    boxed_pair_to_vec();
+}
+
+fn into_raw() {
+    unsafe {
+        let b = Box::new(4i32);
+        let r = Box::into_raw(b);
+
+        // "lose the tag"
+        let r2 = ((r as usize) + 0) as *mut i32;
+        *(&mut *r2) = 7;
+
+        // Use original ptr again
+        *(&mut *r) = 17;
+        drop(Box::from_raw(r));
+    }
+}
+
+fn into_unique() {
+    unsafe {
+        let b = Box::new(4i32);
+        let u = Box::into_unique(b).0;
+
+        // "lose the tag"
+        let r = ((u.as_ptr() as usize) + 0) as *mut i32;
+        *(&mut *r) = 7;
+
+        // Use original ptr again.
+        drop(Box::from_raw(u.as_ptr()));
+    }
+}
+
+fn boxed_pair_to_vec() {
+    #[repr(C)]
+    #[derive(Debug)]
+    struct PairFoo {
+        fst: Foo,
+        snd: Foo,
+    }
+
+    #[derive(Debug)]
+    struct Foo(u64);
+    fn reinterstruct(box_pair: Box<PairFoo>) -> Vec<Foo> {
+        let ref_pair = Box::leak(box_pair) as *mut PairFoo;
+        let ptr_foo = unsafe { std::ptr::addr_of_mut!((*ref_pair).fst) };
+        unsafe { Vec::from_raw_parts(ptr_foo, 2, 2) }
+    }
+
+    let pair_foo = Box::new(PairFoo { fst: Foo(42), snd: Foo(1337) });
+    println!("pair_foo = {:?}", pair_foo);
+    for (n, foo) in reinterstruct(pair_foo).into_iter().enumerate() {
+        println!("foo #{} = {:?}", n, foo);
+    }
+}
diff --git a/src/tools/miri/tests/pass/box.stderr b/src/tools/miri/tests/pass/box.stderr
new file mode 100644
index 000000000000..0001a8dd6eb3
--- /dev/null
+++ b/src/tools/miri/tests/pass/box.stderr
@@ -0,0 +1,33 @@
+warning: integer-to-pointer cast
+  --> $DIR/box.rs:LL:CC
+   |
+LL |         let r2 = ((r as usize) + 0) as *mut i32;
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
+   |
+   = help: This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,
+   = help: which means that Miri might miss pointer bugs in this program.
+   = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation.
+   = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
+   = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics.
+   = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+   = note: BACKTRACE:
+   = note: inside `into_raw` at $DIR/box.rs:LL:CC
+note: inside `main` at $DIR/box.rs:LL:CC
+  --> $DIR/box.rs:LL:CC
+   |
+LL |     into_raw();
+   |     ^^^^^^^^^^
+
+warning: integer-to-pointer cast
+  --> $DIR/box.rs:LL:CC
+   |
+LL |         let r = ((u.as_ptr() as usize) + 0) as *mut i32;
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
+   |
+   = note: inside `into_unique` at $DIR/box.rs:LL:CC
+note: inside `main` at $DIR/box.rs:LL:CC
+  --> $DIR/box.rs:LL:CC
+   |
+LL |     into_unique();
+   |     ^^^^^^^^^^^^^
+
diff --git a/src/tools/miri/tests/pass/box.stdout b/src/tools/miri/tests/pass/box.stdout
new file mode 100644
index 000000000000..230ef368da64
--- /dev/null
+++ b/src/tools/miri/tests/pass/box.stdout
@@ -0,0 +1,3 @@
+pair_foo = PairFoo { fst: Foo(42), snd: Foo(1337) }
+foo #0 = Foo(42)
+foo #1 = Foo(1337)
diff --git a/src/tools/miri/tests/pass/btreemap.rs b/src/tools/miri/tests/pass/btreemap.rs
new file mode 100644
index 000000000000..040c648d4747
--- /dev/null
+++ b/src/tools/miri/tests/pass/btreemap.rs
@@ -0,0 +1,54 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(btree_drain_filter)]
+use std::collections::{BTreeMap, BTreeSet};
+use std::mem;
+
+#[derive(PartialEq, Eq, PartialOrd, Ord)]
+pub enum Foo {
+    A(&'static str),
+    _B,
+    _C,
+}
+
+// Gather all references from a mutable iterator and make sure Miri notices if
+// using them is dangerous.
+fn test_all_refs<'a, T: 'a>(dummy: &mut T, iter: impl Iterator<Item = &'a mut T>) {
+    // Gather all those references.
+    let mut refs: Vec<&mut T> = iter.collect();
+    // Use them all. Twice, to be sure we got all interleavings.
+    for r in refs.iter_mut() {
+        std::mem::swap(dummy, r);
+    }
+    for r in refs {
+        std::mem::swap(dummy, r);
+    }
+}
+
+pub fn main() {
+    let mut b = BTreeSet::new();
+    b.insert(Foo::A("\'"));
+    b.insert(Foo::A("/="));
+    b.insert(Foo::A("#"));
+    b.insert(Foo::A("0o"));
+    assert!(b.remove(&Foo::A("/=")));
+    assert!(!b.remove(&Foo::A("/=")));
+
+    // Also test a lower-alignment type, where the NodeHeader overlaps with
+    // the keys.
+    let mut b = BTreeSet::new();
+    b.insert(1024u16);
+    b.insert(7u16);
+
+    let mut b = BTreeMap::new();
+    b.insert(format!("bar"), 1024);
+    b.insert(format!("baz"), 7);
+    for i in 0..60 {
+        b.insert(format!("key{}", i), i);
+    }
+    test_all_refs(&mut 13, b.values_mut());
+
+    // Test forgetting the drain.
+    let mut d = b.drain_filter(|_, i| *i < 30);
+    d.next().unwrap();
+    mem::forget(d);
+}
diff --git a/src/tools/miri/tests/pass/c_enums.rs b/src/tools/miri/tests/pass/c_enums.rs
new file mode 100644
index 000000000000..16b795342eab
--- /dev/null
+++ b/src/tools/miri/tests/pass/c_enums.rs
@@ -0,0 +1,34 @@
+enum Foo {
+    Bar = 42,
+    Baz,
+    Quux = 100,
+}
+
+enum Signed {
+    Bar = -42,
+    Baz,
+    Quux = 100,
+}
+
+fn foo() -> [u8; 3] {
+    let baz = Foo::Baz; // let-expansion changes the MIR significantly
+    [Foo::Bar as u8, baz as u8, Foo::Quux as u8]
+}
+
+fn signed() -> [i8; 3] {
+    let baz = Signed::Baz; // let-expansion changes the MIR significantly
+    [Signed::Bar as i8, baz as i8, Signed::Quux as i8]
+}
+
+fn unsafe_match() -> bool {
+    match unsafe { std::mem::transmute::<u8, Foo>(43) } {
+        Foo::Baz => true,
+        _ => false,
+    }
+}
+
+fn main() {
+    assert_eq!(foo(), [42, 43, 100]);
+    assert_eq!(signed(), [-42, -41, 100]);
+    assert!(unsafe_match());
+}
diff --git a/src/tools/miri/tests/pass/calls.rs b/src/tools/miri/tests/pass/calls.rs
new file mode 100644
index 000000000000..014d1d3acab7
--- /dev/null
+++ b/src/tools/miri/tests/pass/calls.rs
@@ -0,0 +1,43 @@
+fn call() -> i32 {
+    fn increment(x: i32) -> i32 {
+        x + 1
+    }
+    increment(1)
+}
+
+fn factorial_recursive() -> i64 {
+    fn fact(n: i64) -> i64 {
+        if n == 0 { 1 } else { n * fact(n - 1) }
+    }
+    fact(10)
+}
+
+fn call_generic() -> (i16, bool) {
+    fn id<T>(t: T) -> T {
+        t
+    }
+    (id(42), id(true))
+}
+
+// Test calling a very simple function from the standard library.
+fn cross_crate_fn_call() -> i64 {
+    if 1i32.is_positive() { 1 } else { 0 }
+}
+
+const fn foo(i: i64) -> i64 {
+    *&i + 1
+}
+
+fn const_fn_call() -> i64 {
+    let x = 5 + foo(5);
+    assert_eq!(x, 11);
+    x
+}
+
+fn main() {
+    assert_eq!(call(), 2);
+    assert_eq!(factorial_recursive(), 3628800);
+    assert_eq!(call_generic(), (42, true));
+    assert_eq!(cross_crate_fn_call(), 1);
+    assert_eq!(const_fn_call(), 11);
+}
diff --git a/src/tools/miri/tests/pass/cast-rfc0401-vtable-kinds.rs b/src/tools/miri/tests/pass/cast-rfc0401-vtable-kinds.rs
new file mode 100644
index 000000000000..d76c23633da1
--- /dev/null
+++ b/src/tools/miri/tests/pass/cast-rfc0401-vtable-kinds.rs
@@ -0,0 +1,53 @@
+// Check that you can cast between different pointers to trait objects
+// whose vtable have the same kind (both lengths, or both trait pointers).
+
+trait Foo<T> {
+    fn foo(&self, _: T) -> u32 {
+        42
+    }
+}
+
+trait Bar {
+    fn bar(&self) {
+        println!("Bar!");
+    }
+}
+
+impl<T> Foo<T> for () {}
+impl Foo<u32> for u32 {
+    fn foo(&self, _: u32) -> u32 {
+        self + 43
+    }
+}
+impl Bar for () {}
+
+unsafe fn round_trip_and_call<'a>(t: *const (dyn Foo<u32> + 'a)) -> u32 {
+    let foo_e: *const dyn Foo<u16> = t as *const _;
+    let r_1 = foo_e as *mut dyn Foo<u32>;
+
+    (&*r_1).foo(0)
+}
+
+#[repr(C)]
+struct FooS<T: ?Sized>(T);
+#[repr(C)]
+struct BarS<T: ?Sized>(T);
+
+fn foo_to_bar<T: ?Sized>(u: *const FooS<T>) -> *const BarS<T> {
+    u as *const BarS<T>
+}
+
+fn main() {
+    let x = 4u32;
+    let y: &dyn Foo<u32> = &x;
+    let fl = unsafe { round_trip_and_call(y as *const dyn Foo<u32>) };
+    assert_eq!(fl, (43 + 4));
+
+    let s = FooS([0, 1, 2]);
+    let u: &FooS<[u32]> = &s;
+    let u: *const FooS<[u32]> = u;
+    let bar_ref: *const BarS<[u32]> = foo_to_bar(u);
+    let z: &BarS<[u32]> = unsafe { &*bar_ref };
+    assert_eq!(&z.0, &[0, 1, 2]);
+    // If validation fails here, that's likely because an immutable suspension is recovered mutably.
+}
diff --git a/src/tools/miri/tests/pass/cast_fn_ptr.rs b/src/tools/miri/tests/pass/cast_fn_ptr.rs
new file mode 100644
index 000000000000..8954048f4262
--- /dev/null
+++ b/src/tools/miri/tests/pass/cast_fn_ptr.rs
@@ -0,0 +1,7 @@
+fn main() {
+    fn f(_: *const u8) {}
+
+    let g = unsafe { std::mem::transmute::<fn(*const u8), fn(*const i32)>(f) };
+
+    g(&42 as *const _);
+}
diff --git a/src/tools/miri/tests/pass/cast_fn_ptr_unsafe.rs b/src/tools/miri/tests/pass/cast_fn_ptr_unsafe.rs
new file mode 100644
index 000000000000..0cabb369bfdd
--- /dev/null
+++ b/src/tools/miri/tests/pass/cast_fn_ptr_unsafe.rs
@@ -0,0 +1,8 @@
+fn main() {
+    fn f() {}
+
+    let g = f as fn() as unsafe fn();
+    unsafe {
+        g();
+    }
+}
diff --git a/src/tools/miri/tests/pass/catch.rs b/src/tools/miri/tests/pass/catch.rs
new file mode 100644
index 000000000000..4ede23e68ce2
--- /dev/null
+++ b/src/tools/miri/tests/pass/catch.rs
@@ -0,0 +1,7 @@
+use std::panic::{catch_unwind, AssertUnwindSafe};
+
+fn main() {
+    let mut i = 3;
+    let _val = catch_unwind(AssertUnwindSafe(|| i -= 2));
+    println!("{}", i);
+}
diff --git a/src/tools/miri/tests/pass/catch.stdout b/src/tools/miri/tests/pass/catch.stdout
new file mode 100644
index 000000000000..d00491fd7e5b
--- /dev/null
+++ b/src/tools/miri/tests/pass/catch.stdout
@@ -0,0 +1 @@
+1
diff --git a/src/tools/miri/tests/pass/cfg_miri.rs b/src/tools/miri/tests/pass/cfg_miri.rs
new file mode 100644
index 000000000000..558b9a4f50db
--- /dev/null
+++ b/src/tools/miri/tests/pass/cfg_miri.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert!(cfg!(miri));
+}
diff --git a/src/tools/miri/tests/pass/char.rs b/src/tools/miri/tests/pass/char.rs
new file mode 100644
index 000000000000..5524f0ae7abe
--- /dev/null
+++ b/src/tools/miri/tests/pass/char.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let c = 'x';
+    assert_eq!(c, 'x');
+    assert!('a' < 'z');
+    assert!('1' < '9');
+    assert_eq!(std::char::from_u32('x' as u32), Some('x'));
+}
diff --git a/src/tools/miri/tests/pass/closure-drop.rs b/src/tools/miri/tests/pass/closure-drop.rs
new file mode 100644
index 000000000000..9f9454b4c71c
--- /dev/null
+++ b/src/tools/miri/tests/pass/closure-drop.rs
@@ -0,0 +1,26 @@
+struct Foo<'a>(&'a mut bool);
+
+impl<'a> Drop for Foo<'a> {
+    fn drop(&mut self) {
+        *self.0 = true;
+    }
+}
+
+fn f<T: FnOnce()>(t: T) {
+    t()
+}
+
+fn main() {
+    let mut ran_drop = false;
+    {
+        let x = Foo(&mut ran_drop);
+        // this closure never by val uses its captures
+        // so it's basically a fn(&self)
+        // the shim used to not drop the `x`
+        let x = move || {
+            let _val = x;
+        };
+        f(x);
+    }
+    assert!(ran_drop);
+}
diff --git a/src/tools/miri/tests/pass/closure-field-ty.rs b/src/tools/miri/tests/pass/closure-field-ty.rs
new file mode 100644
index 000000000000..1c90a15f8c5c
--- /dev/null
+++ b/src/tools/miri/tests/pass/closure-field-ty.rs
@@ -0,0 +1,10 @@
+// miri issue #304
+fn main() {
+    let mut y = 0;
+    {
+        let mut box_maybe_closure = Box::new(None);
+        *box_maybe_closure = Some(|| y += 1);
+        (box_maybe_closure.unwrap())();
+    }
+    assert_eq!(y, 1);
+}
diff --git a/src/tools/miri/tests/pass/closures.rs b/src/tools/miri/tests/pass/closures.rs
new file mode 100644
index 000000000000..40aedbcaf454
--- /dev/null
+++ b/src/tools/miri/tests/pass/closures.rs
@@ -0,0 +1,129 @@
+fn simple() -> i32 {
+    let y = 10;
+    let f = |x| x + y;
+    f(2)
+}
+
+fn crazy_closure() -> (i32, i32, i32) {
+    fn inner<T: Copy>(t: T) -> (i32, T, T) {
+        struct NonCopy;
+        let x = NonCopy;
+
+        let a = 2;
+        let b = 40;
+        let f = move |y, z, asdf| {
+            drop(x);
+            (a + b + y + z, asdf, t)
+        };
+        f(a, b, t)
+    }
+
+    inner(10)
+}
+
+fn closure_arg_adjustment_problem() -> i64 {
+    fn once<F: FnOnce(i64)>(f: F) {
+        f(2);
+    }
+    let mut y = 1;
+    {
+        let f = |x| y += x;
+        once(f);
+    }
+    y
+}
+
+fn fn_once_closure_with_multiple_args() -> i64 {
+    fn once<F: FnOnce(i64, i64) -> i64>(f: F) -> i64 {
+        f(2, 3)
+    }
+    let y = 1;
+    {
+        let f = |x, z| x + y + z;
+        once(f)
+    }
+}
+
+fn boxed_fn_once(f: Box<dyn FnOnce() -> i32>) -> i32 {
+    f()
+}
+
+fn box_dyn() {
+    let x: Box<dyn Fn(i32) -> i32> = Box::new(|x| x * 2);
+    assert_eq!(x(21), 42);
+    let mut i = 5;
+    {
+        let mut x: Box<dyn FnMut()> = Box::new(|| i *= 2);
+        x();
+        x();
+    }
+    assert_eq!(i, 20);
+}
+
+fn fn_item_as_closure_trait_object() {
+    fn foo() {}
+    let f: &dyn Fn() = &foo;
+    f();
+}
+
+fn fn_item_with_args_as_closure_trait_object() {
+    fn foo(i: i32) {
+        assert_eq!(i, 42);
+    }
+    let f: &dyn Fn(i32) = &foo;
+    f(42);
+}
+
+fn fn_item_with_multiple_args_as_closure_trait_object() {
+    fn foo(i: i32, j: i32) {
+        assert_eq!(i, 42);
+        assert_eq!(j, 55);
+    }
+
+    fn bar(i: i32, j: i32, k: f32) {
+        assert_eq!(i, 42);
+        assert_eq!(j, 55);
+        assert_eq!(k, 3.14159)
+    }
+    let f: &dyn Fn(i32, i32) = &foo;
+    f(42, 55);
+    let f: &dyn Fn(i32, i32, f32) = &bar;
+    f(42, 55, 3.14159);
+}
+
+fn fn_ptr_as_closure_trait_object() {
+    fn foo() {}
+    fn bar(u: u32) {
+        assert_eq!(u, 42);
+    }
+    fn baa(u: u32, f: f32) {
+        assert_eq!(u, 42);
+        assert_eq!(f, 3.141);
+    }
+    let f: &dyn Fn() = &(foo as fn());
+    f();
+    let f: &dyn Fn(u32) = &(bar as fn(u32));
+    f(42);
+    let f: &dyn Fn(u32, f32) = &(baa as fn(u32, f32));
+    f(42, 3.141);
+}
+
+fn main() {
+    assert_eq!(simple(), 12);
+    assert_eq!(crazy_closure(), (84, 10, 10));
+    assert_eq!(closure_arg_adjustment_problem(), 3);
+    assert_eq!(fn_once_closure_with_multiple_args(), 6);
+    assert_eq!(
+        boxed_fn_once(Box::new({
+            let x = 13;
+            move || x
+        })),
+        13,
+    );
+
+    box_dyn();
+    fn_item_as_closure_trait_object();
+    fn_item_with_args_as_closure_trait_object();
+    fn_item_with_multiple_args_as_closure_trait_object();
+    fn_ptr_as_closure_trait_object();
+}
diff --git a/src/tools/miri/tests/pass/coerce_non_capture_closure_to_fn_ptr.rs b/src/tools/miri/tests/pass/coerce_non_capture_closure_to_fn_ptr.rs
new file mode 100644
index 000000000000..fde120db027b
--- /dev/null
+++ b/src/tools/miri/tests/pass/coerce_non_capture_closure_to_fn_ptr.rs
@@ -0,0 +1,39 @@
+static FOO: fn() = || assert_ne!(42, 43);
+static BAR: fn(i32, i32) = |a, b| assert_ne!(a, b);
+
+// use to first make the closure FnOnce() before making it fn()
+fn force_once0<R, F: FnOnce() -> R>(f: F) -> F {
+    f
+}
+fn force_once1<T, R, F: FnOnce(T) -> R>(f: F) -> F {
+    f
+}
+fn force_mut0<R, F: FnMut() -> R>(f: F) -> F {
+    f
+}
+fn force_mut1<T, R, F: FnMut(T) -> R>(f: F) -> F {
+    f
+}
+
+fn main() {
+    FOO();
+    BAR(44, 45);
+    let bar: unsafe fn(i32, i32) = BAR;
+    unsafe { bar(46, 47) };
+    let boo: &dyn Fn(i32, i32) = &BAR;
+    boo(48, 49);
+
+    let f: fn() = || {};
+    f();
+    let f = force_once0(|| {}) as fn();
+    f();
+    let f = force_mut0(|| {}) as fn();
+    f();
+
+    let g: fn(i32) = |i| assert_eq!(i, 2);
+    g(2);
+    let g = force_once1(|i| assert_eq!(i, 2)) as fn(i32);
+    g(2);
+    let g = force_mut1(|i| assert_eq!(i, 2)) as fn(i32);
+    g(2);
+}
diff --git a/src/tools/miri/tests/pass/coercions.rs b/src/tools/miri/tests/pass/coercions.rs
new file mode 100644
index 000000000000..db0d2ffd44bc
--- /dev/null
+++ b/src/tools/miri/tests/pass/coercions.rs
@@ -0,0 +1,76 @@
+#![feature(coerce_unsized, unsize)]
+
+use std::marker::Unsize;
+use std::ops::CoerceUnsized;
+
+fn identity_coercion(x: &(dyn Fn(u32) -> u32 + Send)) -> &dyn Fn(u32) -> u32 {
+    x
+}
+fn fn_coercions(f: &fn(u32) -> u32) -> (unsafe fn(u32) -> u32, &(dyn Fn(u32) -> u32 + Send)) {
+    (*f, f)
+}
+
+fn simple_array_coercion(x: &[u8; 3]) -> &[u8] {
+    x
+}
+
+fn square(a: u32) -> u32 {
+    a * a
+}
+
+#[derive(PartialEq, Eq)]
+struct PtrWrapper<'a, T: 'a + ?Sized>(u32, u32, (), &'a T);
+impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<PtrWrapper<'a, U>> for PtrWrapper<'a, T> {}
+
+struct TrivPtrWrapper<'a, T: 'a + ?Sized>(&'a T);
+impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<TrivPtrWrapper<'a, U>>
+    for TrivPtrWrapper<'a, T>
+{
+}
+
+fn coerce_ptr_wrapper(p: PtrWrapper<[u8; 3]>) -> PtrWrapper<[u8]> {
+    p
+}
+
+fn coerce_triv_ptr_wrapper(p: TrivPtrWrapper<[u8; 3]>) -> TrivPtrWrapper<[u8]> {
+    p
+}
+
+fn coerce_fat_ptr_wrapper(
+    p: PtrWrapper<dyn Fn(u32) -> u32 + Send>,
+) -> PtrWrapper<dyn Fn(u32) -> u32> {
+    p
+}
+
+fn coerce_ptr_wrapper_poly<'a, T, Trait: ?Sized>(p: PtrWrapper<'a, T>) -> PtrWrapper<'a, Trait>
+where
+    PtrWrapper<'a, T>: CoerceUnsized<PtrWrapper<'a, Trait>>,
+{
+    p
+}
+
+fn main() {
+    let a = [0, 1, 2];
+    let square_local: fn(u32) -> u32 = square;
+    let (f, g) = fn_coercions(&square_local);
+    // cannot use `square as *const ()` because we can't know whether the compiler duplicates
+    // functions, so two function pointers are only equal if they result from the same function
+    // to function pointer cast
+    assert_eq!(f as *const (), square_local as *const ());
+    assert_eq!(g(4), 16);
+    assert_eq!(identity_coercion(g)(5), 25);
+
+    assert_eq!(simple_array_coercion(&a), &a);
+    let w = coerce_ptr_wrapper(PtrWrapper(2, 3, (), &a));
+    assert!(w == PtrWrapper(2, 3, (), &a) as PtrWrapper<[u8]>);
+
+    let w = coerce_triv_ptr_wrapper(TrivPtrWrapper(&a));
+    assert_eq!(&w.0, &a);
+
+    let z = coerce_fat_ptr_wrapper(PtrWrapper(2, 3, (), &square_local));
+    assert_eq!((z.3)(6), 36);
+
+    let z: PtrWrapper<dyn Fn(u32) -> u32> =
+        coerce_ptr_wrapper_poly(PtrWrapper(2, 3, (), &square_local));
+    assert_eq!((z.3)(6), 36);
+}
diff --git a/src/tools/miri/tests/pass/concurrency/channels.rs b/src/tools/miri/tests/pass/concurrency/channels.rs
new file mode 100644
index 000000000000..c75c5199bf11
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/channels.rs
@@ -0,0 +1,66 @@
+//@ignore-target-windows: Channels on Windows are not supported yet.
+//@compile-flags: -Zmiri-strict-provenance
+
+use std::sync::mpsc::{channel, sync_channel};
+use std::thread;
+
+// Check if channels are working.
+
+/// The test taken from the Rust documentation.
+fn simple_send() {
+    let (tx, rx) = channel();
+    let t = thread::spawn(move || {
+        tx.send(10).unwrap();
+    });
+    assert_eq!(rx.recv().unwrap(), 10);
+    t.join().unwrap();
+}
+
+/// The test taken from the Rust documentation.
+fn multiple_send() {
+    let (tx, rx) = channel();
+    let mut threads = vec![];
+    for i in 0..10 {
+        let tx = tx.clone();
+        let t = thread::spawn(move || {
+            tx.send(i).unwrap();
+        });
+        threads.push(t);
+    }
+
+    let mut sum = 0;
+    for _ in 0..10 {
+        let j = rx.recv().unwrap();
+        assert!(0 <= j && j < 10);
+        sum += j;
+    }
+    assert_eq!(sum, 45);
+
+    for t in threads {
+        t.join().unwrap();
+    }
+}
+
+/// The test taken from the Rust documentation.
+fn send_on_sync() {
+    let (sender, receiver) = sync_channel(1);
+
+    // this returns immediately
+    sender.send(1).unwrap();
+
+    let t = thread::spawn(move || {
+        // this will block until the previous message has been received
+        sender.send(2).unwrap();
+    });
+
+    assert_eq!(receiver.recv().unwrap(), 1);
+    assert_eq!(receiver.recv().unwrap(), 2);
+
+    t.join().unwrap();
+}
+
+fn main() {
+    simple_send();
+    multiple_send();
+    send_on_sync();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/concurrent_caller_location.rs b/src/tools/miri/tests/pass/concurrency/concurrent_caller_location.rs
new file mode 100644
index 000000000000..0490330a15d8
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/concurrent_caller_location.rs
@@ -0,0 +1,17 @@
+use std::panic::Location;
+use std::thread::spawn;
+
+fn initialize() {
+    let _ignore = initialize_inner();
+}
+
+fn initialize_inner() -> &'static Location<'static> {
+    Location::caller()
+}
+
+fn main() {
+    let j1 = spawn(initialize);
+    let j2 = spawn(initialize);
+    j1.join().unwrap();
+    j2.join().unwrap();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/data_race.rs b/src/tools/miri/tests/pass/concurrency/data_race.rs
new file mode 100644
index 000000000000..4e3c99058a0d
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/data_race.rs
@@ -0,0 +1,110 @@
+//@compile-flags: -Zmiri-disable-weak-memory-emulation -Zmiri-preemption-rate=0
+
+use std::sync::atomic::{fence, AtomicUsize, Ordering};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+fn test_fence_sync() {
+    static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+    let mut var = 0u32;
+    let ptr = &mut var as *mut u32;
+    let evil_ptr = EvilSend(ptr);
+
+    let j1 = spawn(move || {
+        unsafe { *evil_ptr.0 = 1 };
+        fence(Ordering::Release);
+        SYNC.store(1, Ordering::Relaxed)
+    });
+
+    let j2 = spawn(move || {
+        if SYNC.load(Ordering::Relaxed) == 1 {
+            fence(Ordering::Acquire);
+            unsafe { *evil_ptr.0 }
+        } else {
+            panic!(); // relies on thread 2 going last
+        }
+    });
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+}
+
+fn test_multiple_reads() {
+    let mut var = 42u32;
+    let ptr = &mut var as *mut u32;
+    let evil_ptr = EvilSend(ptr);
+
+    let j1 = spawn(move || unsafe { *evil_ptr.0 });
+    let j2 = spawn(move || unsafe { *evil_ptr.0 });
+    let j3 = spawn(move || unsafe { *evil_ptr.0 });
+    let j4 = spawn(move || unsafe { *evil_ptr.0 });
+
+    assert_eq!(j1.join().unwrap(), 42);
+    assert_eq!(j2.join().unwrap(), 42);
+    assert_eq!(j3.join().unwrap(), 42);
+    assert_eq!(j4.join().unwrap(), 42);
+
+    var = 10;
+    assert_eq!(var, 10);
+}
+
+pub fn test_rmw_no_block() {
+    static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || {
+            if SYNC.swap(2, Ordering::Relaxed) == 1 {
+                //No op, blocking store removed
+            }
+        });
+
+        let j3 = spawn(move || if SYNC.load(Ordering::Acquire) == 2 { *c.0 } else { 0 });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+        let v = j3.join().unwrap();
+        assert!(v == 1 || v == 2); // relies on thread 3 going last
+    }
+}
+
+pub fn test_simple_release() {
+    static SYNC: AtomicUsize = AtomicUsize::new(0);
+
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 1;
+            SYNC.store(1, Ordering::Release);
+        });
+
+        let j2 = spawn(move || if SYNC.load(Ordering::Acquire) == 1 { *c.0 } else { 0 });
+
+        j1.join().unwrap();
+        assert_eq!(j2.join().unwrap(), 1); // relies on thread 2 going last
+    }
+}
+
+pub fn main() {
+    test_fence_sync();
+    test_multiple_reads();
+    test_rmw_no_block();
+    test_simple_release();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/disable_data_race_detector.rs b/src/tools/miri/tests/pass/concurrency/disable_data_race_detector.rs
new file mode 100644
index 000000000000..d71e51b03842
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/disable_data_race_detector.rs
@@ -0,0 +1,27 @@
+//@compile-flags: -Zmiri-disable-data-race-detector
+
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+pub fn main() {
+    let mut a = 0u32;
+    let b = &mut a as *mut u32;
+    let c = EvilSend(b);
+    unsafe {
+        let j1 = spawn(move || {
+            *c.0 = 32;
+        });
+
+        let j2 = spawn(move || {
+            *c.0 = 64; // Data race (but not detected as the detector is disabled)
+        });
+
+        j1.join().unwrap();
+        j2.join().unwrap();
+    }
+}
diff --git a/src/tools/miri/tests/pass/concurrency/issue1643.rs b/src/tools/miri/tests/pass/concurrency/issue1643.rs
new file mode 100644
index 000000000000..c0956569ad8f
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/issue1643.rs
@@ -0,0 +1,14 @@
+use std::thread::spawn;
+
+fn initialize() {
+    initialize_inner(&mut || false)
+}
+
+fn initialize_inner(_init: &mut dyn FnMut() -> bool) {}
+
+fn main() {
+    let j1 = spawn(initialize);
+    let j2 = spawn(initialize);
+    j1.join().unwrap();
+    j2.join().unwrap();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/mutex_leak.rs b/src/tools/miri/tests/pass/concurrency/mutex_leak.rs
new file mode 100644
index 000000000000..3ac0c9336b7b
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/mutex_leak.rs
@@ -0,0 +1,9 @@
+//@compile-flags: -Zmiri-ignore-leaks
+use std::mem;
+use std::sync::Mutex;
+
+fn main() {
+    // Test for https://github.com/rust-lang/rust/issues/85434
+    let m = Mutex::new(5i32);
+    mem::forget(m.lock());
+}
diff --git a/src/tools/miri/tests/pass/concurrency/simple.rs b/src/tools/miri/tests/pass/concurrency/simple.rs
new file mode 100644
index 000000000000..556e0a24769d
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/simple.rs
@@ -0,0 +1,76 @@
+//@compile-flags: -Zmiri-strict-provenance
+
+use std::thread;
+
+fn create_and_detach() {
+    thread::spawn(|| ());
+}
+
+fn create_and_join() {
+    thread::spawn(|| ()).join().unwrap();
+}
+
+fn create_and_get_result() {
+    let nine = thread::spawn(|| 5 + 4).join().unwrap();
+    assert_eq!(nine, 9);
+}
+
+fn create_and_leak_result() {
+    thread::spawn(|| 7);
+}
+
+fn create_nested_and_detach() {
+    thread::spawn(|| {
+        thread::spawn(|| ());
+    });
+}
+
+fn create_nested_and_join() {
+    let handle = thread::spawn(|| thread::spawn(|| ()));
+    let handle_nested = handle.join().unwrap();
+    handle_nested.join().unwrap();
+}
+
+fn create_move_in() {
+    let x = String::from("Hello!");
+    thread::spawn(move || {
+        assert_eq!(x.len(), 6);
+    })
+    .join()
+    .unwrap();
+}
+
+fn create_move_out() {
+    let result = thread::spawn(|| String::from("Hello!")).join().unwrap();
+    assert_eq!(result.len(), 6);
+}
+
+fn panic() {
+    let result = thread::spawn(|| panic!("Hello!")).join().unwrap_err();
+    let msg = result.downcast_ref::<&'static str>().unwrap();
+    assert_eq!(*msg, "Hello!");
+}
+
+fn panic_named() {
+    thread::Builder::new()
+        .name("childthread".to_string())
+        .spawn(move || {
+            panic!("Hello, world!");
+        })
+        .unwrap()
+        .join()
+        .unwrap_err();
+}
+
+fn main() {
+    create_and_detach();
+    create_and_join();
+    create_and_get_result();
+    create_and_leak_result();
+    create_nested_and_detach();
+    create_nested_and_join();
+    create_move_in();
+    create_move_out();
+    panic();
+    panic_named();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/simple.stderr b/src/tools/miri/tests/pass/concurrency/simple.stderr
new file mode 100644
index 000000000000..028cc0fb736f
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/simple.stderr
@@ -0,0 +1,3 @@
+thread '<unnamed>' panicked at 'Hello!', $DIR/simple.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+thread 'childthread' panicked at 'Hello, world!', $DIR/simple.rs:LL:CC
diff --git a/src/tools/miri/tests/pass/concurrency/spin_loop.rs b/src/tools/miri/tests/pass/concurrency/spin_loop.rs
new file mode 100644
index 000000000000..019bd44f1648
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/spin_loop.rs
@@ -0,0 +1,42 @@
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread;
+
+static FLAG: AtomicUsize = AtomicUsize::new(0);
+
+fn spin() {
+    let j = thread::spawn(|| {
+        while FLAG.load(Ordering::Acquire) == 0 {
+            // We do *not* yield, and yet this should terminate eventually.
+        }
+    });
+    thread::yield_now(); // schedule the other thread
+    FLAG.store(1, Ordering::Release);
+    j.join().unwrap();
+}
+
+fn two_player_ping_pong() {
+    static FLAG: AtomicUsize = AtomicUsize::new(0);
+
+    let waiter1 = thread::spawn(|| {
+        while FLAG.load(Ordering::Acquire) == 0 {
+            // We do *not* yield, and yet this should terminate eventually.
+        }
+    });
+    let waiter2 = thread::spawn(|| {
+        while FLAG.load(Ordering::Acquire) == 0 {
+            // We do *not* yield, and yet this should terminate eventually.
+        }
+    });
+    let progress = thread::spawn(|| {
+        FLAG.store(1, Ordering::Release);
+    });
+    // The first `join` blocks the main thread and thus takes it out of the equation.
+    waiter1.join().unwrap();
+    waiter2.join().unwrap();
+    progress.join().unwrap();
+}
+
+fn main() {
+    spin();
+    two_player_ping_pong();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/spin_loops.stderr b/src/tools/miri/tests/pass/concurrency/spin_loops.stderr
new file mode 100644
index 000000000000..9fe6daa778c1
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/spin_loops.stderr
@@ -0,0 +1,3 @@
+warning: thread support is experimental: the scheduler is not preemptive, and can get stuck in spin loops.
+         (see https://github.com/rust-lang/miri/issues/1388)
+
diff --git a/src/tools/miri/tests/pass/concurrency/spin_loops_nopreempt.rs b/src/tools/miri/tests/pass/concurrency/spin_loops_nopreempt.rs
new file mode 100644
index 000000000000..5d8e2ef5f028
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/spin_loops_nopreempt.rs
@@ -0,0 +1,84 @@
+//@ignore-target-windows: Channels on Windows are not supported yet.
+// This specifically tests behavior *without* preemption.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::cell::Cell;
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use std::sync::mpsc;
+use std::thread;
+
+/// When a thread yields, Miri's scheduler used to pick the thread with the lowest ID
+/// that can run. IDs are assigned in thread creation order.
+/// This means we could make 2 threads infinitely ping-pong with each other while
+/// really there is a 3rd thread that we should schedule to make progress.
+fn two_player_ping_pong() {
+    static FLAG: AtomicUsize = AtomicUsize::new(0);
+
+    let waiter1 = thread::spawn(|| {
+        while FLAG.load(Ordering::Acquire) == 0 {
+            // spin and wait
+            thread::yield_now();
+        }
+    });
+    let waiter2 = thread::spawn(|| {
+        while FLAG.load(Ordering::Acquire) == 0 {
+            // spin and wait
+            thread::yield_now();
+        }
+    });
+    let progress = thread::spawn(|| {
+        FLAG.store(1, Ordering::Release);
+    });
+    // The first `join` blocks the main thread and thus takes it out of the equation.
+    waiter1.join().unwrap();
+    waiter2.join().unwrap();
+    progress.join().unwrap();
+}
+
+/// Based on a test by @jethrogb.
+fn launcher() {
+    static THREAD2_LAUNCHED: AtomicBool = AtomicBool::new(false);
+
+    for _ in 0..10 {
+        let (tx, rx) = mpsc::sync_channel(0);
+        THREAD2_LAUNCHED.store(false, Ordering::SeqCst);
+
+        let jh = thread::spawn(move || {
+            struct RecvOnDrop(Cell<Option<mpsc::Receiver<()>>>);
+
+            impl Drop for RecvOnDrop {
+                fn drop(&mut self) {
+                    let rx = self.0.take().unwrap();
+                    while !THREAD2_LAUNCHED.load(Ordering::SeqCst) {
+                        thread::yield_now();
+                    }
+                    rx.recv().unwrap();
+                }
+            }
+
+            let tl_rx: RecvOnDrop = RecvOnDrop(Cell::new(None));
+            tl_rx.0.set(Some(rx));
+        });
+
+        let tx_clone = tx.clone();
+        let jh2 = thread::spawn(move || {
+            THREAD2_LAUNCHED.store(true, Ordering::SeqCst);
+            jh.join().unwrap();
+            tx_clone.send(()).expect_err(
+                "Expecting channel to be closed because thread 1 TLS destructors must've run",
+            );
+        });
+
+        while !THREAD2_LAUNCHED.load(Ordering::SeqCst) {
+            thread::yield_now();
+        }
+        thread::yield_now();
+        tx.send(()).expect("Expecting channel to be live because thread 2 must block on join");
+        jh2.join().unwrap();
+    }
+}
+
+fn main() {
+    two_player_ping_pong();
+    launcher();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/sync.rs b/src/tools/miri/tests/pass/concurrency/sync.rs
new file mode 100644
index 000000000000..8bda32bb95a4
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/sync.rs
@@ -0,0 +1,238 @@
+//@ignore-target-windows: Concurrency on Windows is not supported yet.
+//@compile-flags: -Zmiri-disable-isolation -Zmiri-strict-provenance
+
+use std::sync::{Arc, Barrier, Condvar, Mutex, Once, RwLock};
+use std::thread;
+use std::time::{Duration, Instant};
+
+// Check if Rust barriers are working.
+
+/// This test is taken from the Rust documentation.
+fn check_barriers() {
+    let mut handles = Vec::with_capacity(10);
+    let barrier = Arc::new(Barrier::new(10));
+    for _ in 0..10 {
+        let c = barrier.clone();
+        // The same messages will be printed together.
+        // You will NOT see any interleaving.
+        handles.push(thread::spawn(move || {
+            println!("before wait");
+            c.wait();
+            println!("after wait");
+        }));
+    }
+    // Wait for other threads to finish.
+    for handle in handles {
+        handle.join().unwrap();
+    }
+}
+
+// Check if Rust conditional variables are working.
+
+/// The test taken from the Rust documentation.
+fn check_conditional_variables_notify_one() {
+    let pair = Arc::new((Mutex::new(false), Condvar::new()));
+    let pair2 = pair.clone();
+
+    // Spawn a new thread.
+    let t = thread::spawn(move || {
+        thread::yield_now();
+        let (lock, cvar) = &*pair2;
+        let mut started = lock.lock().unwrap();
+        *started = true;
+        // We notify the condvar that the value has changed.
+        cvar.notify_one();
+    });
+
+    // Wait for the thread to fully start up.
+    let (lock, cvar) = &*pair;
+    let mut started = lock.lock().unwrap();
+    while !*started {
+        started = cvar.wait(started).unwrap();
+    }
+
+    t.join().unwrap();
+}
+
+/// Test that waiting on a conditional variable with a timeout does not
+/// deadlock.
+fn check_conditional_variables_timed_wait_timeout() {
+    let lock = Mutex::new(());
+    let cvar = Condvar::new();
+    let guard = lock.lock().unwrap();
+    let now = Instant::now();
+    let (_guard, timeout) = cvar.wait_timeout(guard, Duration::from_millis(100)).unwrap();
+    assert!(timeout.timed_out());
+    let elapsed_time = now.elapsed().as_millis();
+    assert!(100 <= elapsed_time && elapsed_time <= 1000);
+}
+
+/// Test that signaling a conditional variable when waiting with a timeout works
+/// as expected.
+fn check_conditional_variables_timed_wait_notimeout() {
+    let pair = Arc::new((Mutex::new(()), Condvar::new()));
+    let pair2 = pair.clone();
+
+    let (lock, cvar) = &*pair;
+    let guard = lock.lock().unwrap();
+
+    let handle = thread::spawn(move || {
+        thread::sleep(Duration::from_millis(100)); // Make sure the other thread is waiting by the time we call `notify`.
+        let (_lock, cvar) = &*pair2;
+        cvar.notify_one();
+    });
+
+    let (_guard, timeout) = cvar.wait_timeout(guard, Duration::from_millis(500)).unwrap();
+    assert!(!timeout.timed_out());
+    handle.join().unwrap();
+}
+
+// Check if locks are working.
+
+fn check_mutex() {
+    let data = Arc::new(Mutex::new(0));
+    let mut threads = Vec::new();
+
+    for _ in 0..3 {
+        let data = Arc::clone(&data);
+        let thread = thread::spawn(move || {
+            let mut data = data.lock().unwrap();
+            thread::yield_now();
+            *data += 1;
+        });
+        threads.push(thread);
+    }
+
+    for thread in threads {
+        thread.join().unwrap();
+    }
+
+    assert!(data.try_lock().is_ok());
+
+    let data = Arc::try_unwrap(data).unwrap().into_inner().unwrap();
+    assert_eq!(data, 3);
+}
+
+fn check_rwlock_write() {
+    let data = Arc::new(RwLock::new(0));
+    let mut threads = Vec::new();
+
+    for _ in 0..3 {
+        let data = Arc::clone(&data);
+        let thread = thread::spawn(move || {
+            let mut data = data.write().unwrap();
+            thread::yield_now();
+            *data += 1;
+        });
+        threads.push(thread);
+    }
+
+    for thread in threads {
+        thread.join().unwrap();
+    }
+
+    assert!(data.try_write().is_ok());
+
+    let data = Arc::try_unwrap(data).unwrap().into_inner().unwrap();
+    assert_eq!(data, 3);
+}
+
+fn check_rwlock_read_no_deadlock() {
+    let l1 = Arc::new(RwLock::new(0));
+    let l2 = Arc::new(RwLock::new(0));
+
+    let l1_copy = Arc::clone(&l1);
+    let l2_copy = Arc::clone(&l2);
+    let _guard1 = l1.read().unwrap();
+    let handle = thread::spawn(move || {
+        let _guard2 = l2_copy.read().unwrap();
+        thread::yield_now();
+        let _guard1 = l1_copy.read().unwrap();
+    });
+    thread::yield_now();
+    let _guard2 = l2.read().unwrap();
+    handle.join().unwrap();
+}
+
+// Check if Rust once statics are working.
+
+static mut VAL: usize = 0;
+static INIT: Once = Once::new();
+
+fn get_cached_val() -> usize {
+    unsafe {
+        INIT.call_once(|| {
+            VAL = expensive_computation();
+        });
+        VAL
+    }
+}
+
+fn expensive_computation() -> usize {
+    let mut i = 1;
+    let mut c = 1;
+    while i < 1000 {
+        i *= c;
+        c += 1;
+    }
+    i
+}
+
+/// The test taken from the Rust documentation.
+fn check_once() {
+    let handles: Vec<_> = (0..10)
+        .map(|_| {
+            thread::spawn(|| {
+                thread::yield_now();
+                let val = get_cached_val();
+                assert_eq!(val, 5040);
+            })
+        })
+        .collect();
+    for handle in handles {
+        handle.join().unwrap();
+    }
+}
+
+fn park_timeout() {
+    let start = Instant::now();
+
+    thread::park_timeout(Duration::from_millis(200));
+    // Normally, waiting in park/park_timeout may spuriously wake up early, but we
+    // know Miri's timed synchronization primitives do not do that.
+
+    assert!((200..1000).contains(&start.elapsed().as_millis()));
+}
+
+fn park_unpark() {
+    let t1 = thread::current();
+    let t2 = thread::spawn(move || {
+        thread::park();
+        thread::sleep(Duration::from_millis(200));
+        t1.unpark();
+    });
+
+    let start = Instant::now();
+
+    t2.thread().unpark();
+    thread::park();
+    // Normally, waiting in park/park_timeout may spuriously wake up early, but we
+    // know Miri's timed synchronization primitives do not do that.
+
+    assert!((200..1000).contains(&start.elapsed().as_millis()));
+
+    t2.join().unwrap();
+}
+
+fn main() {
+    check_barriers();
+    check_conditional_variables_notify_one();
+    check_conditional_variables_timed_wait_timeout();
+    check_conditional_variables_timed_wait_notimeout();
+    check_mutex();
+    check_rwlock_write();
+    check_rwlock_read_no_deadlock();
+    check_once();
+    park_timeout();
+    park_unpark();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/sync.stdout b/src/tools/miri/tests/pass/concurrency/sync.stdout
new file mode 100644
index 000000000000..f2c036a1735e
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/sync.stdout
@@ -0,0 +1,20 @@
+before wait
+before wait
+before wait
+before wait
+before wait
+before wait
+before wait
+before wait
+before wait
+before wait
+after wait
+after wait
+after wait
+after wait
+after wait
+after wait
+after wait
+after wait
+after wait
+after wait
diff --git a/src/tools/miri/tests/pass/concurrency/sync_nopreempt.rs b/src/tools/miri/tests/pass/concurrency/sync_nopreempt.rs
new file mode 100644
index 000000000000..3da33fee4c0e
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/sync_nopreempt.rs
@@ -0,0 +1,88 @@
+//@ignore-target-windows: Concurrency on Windows is not supported yet.
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-strict-provenance -Zmiri-preemption-rate=0
+
+use std::sync::{Arc, Condvar, Mutex, RwLock};
+use std::thread;
+
+fn check_conditional_variables_notify_all() {
+    let pair = Arc::new(((Mutex::new(())), Condvar::new()));
+
+    // Spawn threads and block them on the conditional variable.
+    let handles: Vec<_> = (0..5)
+        .map(|_| {
+            let pair2 = pair.clone();
+            thread::spawn(move || {
+                let (lock, cvar) = &*pair2;
+                let guard = lock.lock().unwrap();
+                // Block waiting on the conditional variable.
+                let _guard = cvar.wait(guard).unwrap();
+            })
+        })
+        .inspect(|_| {
+            // Ensure the other threads all run and block on the `wait`.
+            thread::yield_now();
+            thread::yield_now();
+        })
+        .collect();
+
+    let (_, cvar) = &*pair;
+    // Unblock all threads.
+    cvar.notify_all();
+
+    for handle in handles {
+        handle.join().unwrap();
+    }
+}
+
+fn check_rwlock_unlock_bug1() {
+    // There was a bug where when un-read-locking an rwlock that still has other
+    // readers waiting, we'd accidentally also let a writer in.
+    // That caused an ICE.
+    let l = Arc::new(RwLock::new(0));
+
+    let r1 = l.read().unwrap();
+    let r2 = l.read().unwrap();
+
+    // Make a waiting writer.
+    let l2 = l.clone();
+    let t = thread::spawn(move || {
+        let mut w = l2.write().unwrap();
+        *w += 1;
+    });
+    thread::yield_now();
+
+    drop(r1);
+    assert_eq!(*r2, 0);
+    thread::yield_now();
+    thread::yield_now();
+    thread::yield_now();
+    assert_eq!(*r2, 0);
+    drop(r2);
+    t.join().unwrap();
+}
+
+fn check_rwlock_unlock_bug2() {
+    // There was a bug where when un-read-locking an rwlock by letting the last reader leaver,
+    // we'd forget to wake up a writer.
+    // That meant the writer thread could never run again.
+    let l = Arc::new(RwLock::new(0));
+
+    let r = l.read().unwrap();
+
+    // Make a waiting writer.
+    let l2 = l.clone();
+    let h = thread::spawn(move || {
+        let _w = l2.write().unwrap();
+    });
+    thread::yield_now();
+
+    drop(r);
+    h.join().unwrap();
+}
+
+fn main() {
+    check_conditional_variables_notify_all();
+    check_rwlock_unlock_bug1();
+    check_rwlock_unlock_bug2();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/sync_singlethread.rs b/src/tools/miri/tests/pass/concurrency/sync_singlethread.rs
new file mode 100644
index 000000000000..5663e1c1426c
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/sync_singlethread.rs
@@ -0,0 +1,60 @@
+use std::hint;
+use std::sync::atomic;
+use std::sync::{Mutex, TryLockError};
+
+fn main() {
+    test_mutex_stdlib();
+    test_rwlock_stdlib();
+    test_spin_loop_hint();
+    test_thread_yield_now();
+}
+
+fn test_mutex_stdlib() {
+    let m = Mutex::new(0);
+    {
+        let _guard = m.lock();
+        assert!(m.try_lock().unwrap_err().would_block());
+    }
+    drop(m.try_lock().unwrap());
+    drop(m);
+}
+
+fn test_rwlock_stdlib() {
+    use std::sync::RwLock;
+    let rw = RwLock::new(0);
+    {
+        let _read_guard = rw.read().unwrap();
+        drop(rw.read().unwrap());
+        drop(rw.try_read().unwrap());
+        assert!(rw.try_write().unwrap_err().would_block());
+    }
+
+    {
+        let _write_guard = rw.write().unwrap();
+        assert!(rw.try_read().unwrap_err().would_block());
+        assert!(rw.try_write().unwrap_err().would_block());
+    }
+}
+
+trait TryLockErrorExt<T> {
+    fn would_block(&self) -> bool;
+}
+
+impl<T> TryLockErrorExt<T> for TryLockError<T> {
+    fn would_block(&self) -> bool {
+        match self {
+            TryLockError::WouldBlock => true,
+            TryLockError::Poisoned(_) => false,
+        }
+    }
+}
+
+fn test_spin_loop_hint() {
+    #[allow(deprecated)]
+    atomic::spin_loop_hint();
+    hint::spin_loop();
+}
+
+fn test_thread_yield_now() {
+    std::thread::yield_now();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/thread_locals.rs b/src/tools/miri/tests/pass/concurrency/thread_locals.rs
new file mode 100644
index 000000000000..b19e56312f30
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/thread_locals.rs
@@ -0,0 +1,65 @@
+//@compile-flags: -Zmiri-strict-provenance
+
+//! The main purpose of this test is to check that if we take a pointer to
+//! thread's `t1` thread-local `A` and send it to another thread `t2`,
+//! dereferencing the pointer on `t2` resolves to `t1`'s thread-local. In this
+//! test, we also check that thread-locals act as per-thread statics.
+
+#![feature(thread_local)]
+
+use std::thread;
+
+#[thread_local]
+static mut A: u8 = 0;
+#[thread_local]
+static mut B: u8 = 0;
+static mut C: u8 = 0;
+
+// Regression test for https://github.com/rust-lang/rust/issues/96191.
+#[thread_local]
+static READ_ONLY: u8 = 42;
+
+unsafe fn get_a_ref() -> *mut u8 {
+    &mut A
+}
+
+struct Sender(*mut u8);
+
+unsafe impl Send for Sender {}
+
+fn main() {
+    let _val = READ_ONLY;
+
+    let ptr = unsafe {
+        let x = get_a_ref();
+        *x = 5;
+        assert_eq!(A, 5);
+        B = 15;
+        C = 25;
+        Sender(&mut A)
+    };
+
+    thread::spawn(move || unsafe {
+        assert_eq!(*ptr.0, 5);
+        assert_eq!(A, 0);
+        assert_eq!(B, 0);
+        assert_eq!(C, 25);
+        B = 14;
+        C = 24;
+        let y = get_a_ref();
+        assert_eq!(*y, 0);
+        *y = 4;
+        assert_eq!(*ptr.0, 5);
+        assert_eq!(A, 4);
+        assert_eq!(*get_a_ref(), 4);
+    })
+    .join()
+    .unwrap();
+
+    unsafe {
+        assert_eq!(*get_a_ref(), 5);
+        assert_eq!(A, 5);
+        assert_eq!(B, 15);
+        assert_eq!(C, 24);
+    }
+}
diff --git a/src/tools/miri/tests/pass/concurrency/tls_lib_drop.rs b/src/tools/miri/tests/pass/concurrency/tls_lib_drop.rs
new file mode 100644
index 000000000000..04e89ec361b7
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/tls_lib_drop.rs
@@ -0,0 +1,193 @@
+use std::cell::RefCell;
+use std::thread;
+
+struct TestCell {
+    value: RefCell<u8>,
+}
+
+impl Drop for TestCell {
+    fn drop(&mut self) {
+        for _ in 0..10 {
+            thread::yield_now();
+        }
+        println!("Dropping: {} (should be before 'Continue main 1').", *self.value.borrow())
+    }
+}
+
+thread_local! {
+    static A: TestCell = TestCell { value: RefCell::new(0) };
+    static A_CONST: TestCell = const { TestCell { value: RefCell::new(10) } };
+}
+
+/// Check that destructors of the library thread locals are executed immediately
+/// after a thread terminates.
+fn check_destructors() {
+    // We use the same value for both of them, since destructor order differs between Miri on Linux
+    // (which uses `register_dtor_fallback`, in the end using a single pthread_key to manage a
+    // thread-local linked list of dtors to call), real Linux rustc (which uses
+    // `__cxa_thread_atexit_impl`), and Miri on Windows.
+    thread::spawn(|| {
+        A.with(|f| {
+            assert_eq!(*f.value.borrow(), 0);
+            *f.value.borrow_mut() = 8;
+        });
+        A_CONST.with(|f| {
+            assert_eq!(*f.value.borrow(), 10);
+            *f.value.borrow_mut() = 8;
+        });
+    })
+    .join()
+    .unwrap();
+    println!("Continue main 1.")
+}
+
+struct JoinCell {
+    value: RefCell<Option<thread::JoinHandle<u8>>>,
+}
+
+impl Drop for JoinCell {
+    fn drop(&mut self) {
+        for _ in 0..10 {
+            thread::yield_now();
+        }
+        let join_handle = self.value.borrow_mut().take().unwrap();
+        println!("Joining: {} (should be before 'Continue main 2').", join_handle.join().unwrap());
+    }
+}
+
+thread_local! {
+    static B: JoinCell = JoinCell { value: RefCell::new(None) };
+}
+
+/// Check that the destructor can be blocked joining another thread.
+fn check_blocking() {
+    thread::spawn(|| {
+        B.with(|f| {
+            assert!(f.value.borrow().is_none());
+            let handle = thread::spawn(|| 7);
+            *f.value.borrow_mut() = Some(handle);
+        });
+    })
+    .join()
+    .unwrap();
+    println!("Continue main 2.");
+    // Preempt the main thread so that the destructor gets executed and can join
+    // the thread.
+    thread::yield_now();
+    thread::yield_now();
+}
+
+// This test tests that TLS destructors have run before the thread joins. The
+// test has no false positives (meaning: if the test fails, there's actually
+// an ordering problem). It may have false negatives, where the test passes but
+// join is not guaranteed to be after the TLS destructors. However, false
+// negatives should be exceedingly rare due to judicious use of
+// thread::yield_now and running the test several times.
+fn join_orders_after_tls_destructors() {
+    use std::sync::atomic::{AtomicU8, Ordering};
+
+    // We emulate a synchronous MPSC rendezvous channel using only atomics and
+    // thread::yield_now. We can't use std::mpsc as the implementation itself
+    // may rely on thread locals.
+    //
+    // The basic state machine for an SPSC rendezvous channel is:
+    //           FRESH -> THREAD1_WAITING -> MAIN_THREAD_RENDEZVOUS
+    // where the first transition is done by the “receiving” thread and the 2nd
+    // transition is done by the “sending” thread.
+    //
+    // We add an additional state `THREAD2_LAUNCHED` between `FRESH` and
+    // `THREAD1_WAITING` to block until all threads are actually running.
+    //
+    // A thread that joins on the “receiving” thread completion should never
+    // observe the channel in the `THREAD1_WAITING` state. If this does occur,
+    // we switch to the “poison” state `THREAD2_JOINED` and panic all around.
+    // (This is equivalent to “sending” from an alternate producer thread.)
+    const FRESH: u8 = 0;
+    const THREAD2_LAUNCHED: u8 = 1;
+    const THREAD1_WAITING: u8 = 2;
+    const MAIN_THREAD_RENDEZVOUS: u8 = 3;
+    const THREAD2_JOINED: u8 = 4;
+    static SYNC_STATE: AtomicU8 = AtomicU8::new(FRESH);
+
+    for _ in 0..10 {
+        SYNC_STATE.store(FRESH, Ordering::SeqCst);
+
+        let jh = thread::Builder::new()
+            .name("thread1".into())
+            .spawn(move || {
+                struct TlDrop;
+
+                impl Drop for TlDrop {
+                    fn drop(&mut self) {
+                        let mut sync_state = SYNC_STATE.swap(THREAD1_WAITING, Ordering::SeqCst);
+                        loop {
+                            match sync_state {
+                                THREAD2_LAUNCHED | THREAD1_WAITING => thread::yield_now(),
+                                MAIN_THREAD_RENDEZVOUS => break,
+                                THREAD2_JOINED =>
+                                    panic!(
+                                        "Thread 1 still running after thread 2 joined on thread 1"
+                                    ),
+                                v => unreachable!("sync state: {}", v),
+                            }
+                            sync_state = SYNC_STATE.load(Ordering::SeqCst);
+                        }
+                    }
+                }
+
+                thread_local! {
+                    static TL_DROP: TlDrop = TlDrop;
+                }
+
+                TL_DROP.with(|_| {});
+
+                loop {
+                    match SYNC_STATE.load(Ordering::SeqCst) {
+                        FRESH => thread::yield_now(),
+                        THREAD2_LAUNCHED => break,
+                        v => unreachable!("sync state: {}", v),
+                    }
+                }
+            })
+            .unwrap();
+
+        let jh2 = thread::Builder::new()
+            .name("thread2".into())
+            .spawn(move || {
+                assert_eq!(SYNC_STATE.swap(THREAD2_LAUNCHED, Ordering::SeqCst), FRESH);
+                jh.join().unwrap();
+                match SYNC_STATE.swap(THREAD2_JOINED, Ordering::SeqCst) {
+                    MAIN_THREAD_RENDEZVOUS => return,
+                    THREAD2_LAUNCHED | THREAD1_WAITING => {
+                        panic!("Thread 2 running after thread 1 join before main thread rendezvous")
+                    }
+                    v => unreachable!("sync state: {:?}", v),
+                }
+            })
+            .unwrap();
+
+        loop {
+            match SYNC_STATE.compare_exchange(
+                THREAD1_WAITING,
+                MAIN_THREAD_RENDEZVOUS,
+                Ordering::SeqCst,
+                Ordering::SeqCst,
+            ) {
+                Ok(_) => break,
+                Err(FRESH) => thread::yield_now(),
+                Err(THREAD2_LAUNCHED) => thread::yield_now(),
+                Err(THREAD2_JOINED) => {
+                    panic!("Main thread rendezvous after thread 2 joined thread 1")
+                }
+                v => unreachable!("sync state: {:?}", v),
+            }
+        }
+        jh2.join().unwrap();
+    }
+}
+
+fn main() {
+    check_destructors();
+    check_blocking();
+    join_orders_after_tls_destructors();
+}
diff --git a/src/tools/miri/tests/pass/concurrency/tls_lib_drop.stdout b/src/tools/miri/tests/pass/concurrency/tls_lib_drop.stdout
new file mode 100644
index 000000000000..b7877820a0ca
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/tls_lib_drop.stdout
@@ -0,0 +1,5 @@
+Dropping: 8 (should be before 'Continue main 1').
+Dropping: 8 (should be before 'Continue main 1').
+Continue main 1.
+Joining: 7 (should be before 'Continue main 2').
+Continue main 2.
diff --git a/src/tools/miri/tests/pass/concurrency/tls_lib_drop_single_thread.rs b/src/tools/miri/tests/pass/concurrency/tls_lib_drop_single_thread.rs
new file mode 100644
index 000000000000..2766ba36d12b
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/tls_lib_drop_single_thread.rs
@@ -0,0 +1,30 @@
+//! Check that destructors of the thread locals are executed on all OSes.
+
+use std::cell::RefCell;
+
+struct TestCell {
+    value: RefCell<u8>,
+}
+
+impl Drop for TestCell {
+    fn drop(&mut self) {
+        eprintln!("Dropping: {}", *self.value.borrow())
+    }
+}
+
+thread_local! {
+    static A: TestCell = TestCell { value: RefCell::new(0) };
+    static A_CONST: TestCell = const { TestCell { value: RefCell::new(10) } };
+}
+
+fn main() {
+    A.with(|f| {
+        assert_eq!(*f.value.borrow(), 0);
+        *f.value.borrow_mut() = 5;
+    });
+    A_CONST.with(|f| {
+        assert_eq!(*f.value.borrow(), 10);
+        *f.value.borrow_mut() = 5; // Same value as above since the drop order is different on different platforms
+    });
+    eprintln!("Continue main.")
+}
diff --git a/src/tools/miri/tests/pass/concurrency/tls_lib_drop_single_thread.stderr b/src/tools/miri/tests/pass/concurrency/tls_lib_drop_single_thread.stderr
new file mode 100644
index 000000000000..09ec1c3c2c51
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/tls_lib_drop_single_thread.stderr
@@ -0,0 +1,3 @@
+Continue main.
+Dropping: 5
+Dropping: 5
diff --git a/src/tools/miri/tests/pass/concurrency/windows_detach_terminated.rs b/src/tools/miri/tests/pass/concurrency/windows_detach_terminated.rs
new file mode 100644
index 000000000000..91088ce6aef9
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/windows_detach_terminated.rs
@@ -0,0 +1,21 @@
+//@only-target-windows: Uses win32 api functions
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::os::windows::io::IntoRawHandle;
+use std::thread;
+
+extern "system" {
+    fn CloseHandle(handle: usize) -> i32;
+}
+
+fn main() {
+    let thread = thread::spawn(|| {}).into_raw_handle() as usize;
+
+    // this yield ensures that `thread` is terminated by this point
+    thread::yield_now();
+
+    unsafe {
+        assert_ne!(CloseHandle(thread), 0);
+    }
+}
diff --git a/src/tools/miri/tests/pass/concurrency/windows_join_multiple.rs b/src/tools/miri/tests/pass/concurrency/windows_join_multiple.rs
new file mode 100644
index 000000000000..986e2b8cc10f
--- /dev/null
+++ b/src/tools/miri/tests/pass/concurrency/windows_join_multiple.rs
@@ -0,0 +1,41 @@
+//@only-target-windows: Uses win32 api functions
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+use std::os::windows::io::IntoRawHandle;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+
+extern "system" {
+    fn WaitForSingleObject(handle: usize, timeout: u32) -> u32;
+}
+
+const INFINITE: u32 = u32::MAX;
+
+fn main() {
+    static FLAG: AtomicBool = AtomicBool::new(false);
+
+    let blocker = thread::spawn(|| {
+        while !FLAG.load(Ordering::Relaxed) {
+            thread::yield_now();
+        }
+    })
+    .into_raw_handle() as usize;
+
+    let waiter = move || {
+        unsafe {
+            assert_eq!(WaitForSingleObject(blocker, INFINITE), 0);
+        }
+    };
+
+    let waiter1 = thread::spawn(waiter);
+    let waiter2 = thread::spawn(waiter);
+
+    // this yield ensures `waiter1` & `waiter2` are blocked on `blocker` by this point
+    thread::yield_now();
+
+    FLAG.store(true, Ordering::Relaxed);
+
+    waiter1.join().unwrap();
+    waiter2.join().unwrap();
+}
diff --git a/src/tools/miri/tests/pass/const-vec-of-fns.rs b/src/tools/miri/tests/pass/const-vec-of-fns.rs
new file mode 100644
index 000000000000..7f0782fe3224
--- /dev/null
+++ b/src/tools/miri/tests/pass/const-vec-of-fns.rs
@@ -0,0 +1,17 @@
+/*!
+ * Try to double-check that static fns have the right size (with or
+ * without dummy env ptr, as appropriate) by iterating a size-2 array.
+ * If the static size differs from the runtime size, the second element
+ * should be read as a null or otherwise wrong pointer and crash.
+ */
+
+fn f() {}
+static mut CLOSURES: &'static mut [fn()] = &mut [f as fn(), f as fn()];
+
+pub fn main() {
+    unsafe {
+        for closure in &mut *CLOSURES {
+            (*closure)()
+        }
+    }
+}
diff --git a/src/tools/miri/tests/pass/constants.rs b/src/tools/miri/tests/pass/constants.rs
new file mode 100644
index 000000000000..718c85260142
--- /dev/null
+++ b/src/tools/miri/tests/pass/constants.rs
@@ -0,0 +1,9 @@
+const A: usize = *&5;
+
+fn foo() -> usize {
+    A
+}
+
+fn main() {
+    assert_eq!(foo(), A);
+}
diff --git a/src/tools/miri/tests/pass/deriving-associated-types.rs b/src/tools/miri/tests/pass/deriving-associated-types.rs
new file mode 100644
index 000000000000..4803792a97ce
--- /dev/null
+++ b/src/tools/miri/tests/pass/deriving-associated-types.rs
@@ -0,0 +1,159 @@
+pub trait DeclaredTrait {
+    type Type;
+}
+
+impl DeclaredTrait for i32 {
+    type Type = i32;
+}
+
+pub trait WhereTrait {
+    type Type;
+}
+
+impl WhereTrait for i32 {
+    type Type = i32;
+}
+
+// Make sure we don't add a bound that just shares a name with an associated
+// type.
+pub mod module {
+    pub type Type = i32;
+}
+
+#[derive(PartialEq, Debug)]
+struct PrivateStruct<T>(T);
+
+#[derive(PartialEq, Debug)]
+struct TupleStruct<A, B: DeclaredTrait, C>(
+    module::Type,
+    Option<module::Type>,
+    A,
+    PrivateStruct<A>,
+    B,
+    B::Type,
+    Option<B::Type>,
+    <B as DeclaredTrait>::Type,
+    Option<<B as DeclaredTrait>::Type>,
+    C,
+    C::Type,
+    Option<C::Type>,
+    <C as WhereTrait>::Type,
+    Option<<C as WhereTrait>::Type>,
+    <i32 as DeclaredTrait>::Type,
+)
+where
+    C: WhereTrait;
+
+#[derive(PartialEq, Debug)]
+pub struct Struct<A, B: DeclaredTrait, C>
+where
+    C: WhereTrait,
+{
+    m1: module::Type,
+    m2: Option<module::Type>,
+    a1: A,
+    a2: PrivateStruct<A>,
+    b: B,
+    b1: B::Type,
+    b2: Option<B::Type>,
+    b3: <B as DeclaredTrait>::Type,
+    b4: Option<<B as DeclaredTrait>::Type>,
+    c: C,
+    c1: C::Type,
+    c2: Option<C::Type>,
+    c3: <C as WhereTrait>::Type,
+    c4: Option<<C as WhereTrait>::Type>,
+    d: <i32 as DeclaredTrait>::Type,
+}
+
+#[derive(PartialEq, Debug)]
+enum Enum<A, B: DeclaredTrait, C>
+where
+    C: WhereTrait,
+{
+    Unit,
+    Seq(
+        module::Type,
+        Option<module::Type>,
+        A,
+        PrivateStruct<A>,
+        B,
+        B::Type,
+        Option<B::Type>,
+        <B as DeclaredTrait>::Type,
+        Option<<B as DeclaredTrait>::Type>,
+        C,
+        C::Type,
+        Option<C::Type>,
+        <C as WhereTrait>::Type,
+        Option<<C as WhereTrait>::Type>,
+        <i32 as DeclaredTrait>::Type,
+    ),
+    Map {
+        m1: module::Type,
+        m2: Option<module::Type>,
+        a1: A,
+        a2: PrivateStruct<A>,
+        b: B,
+        b1: B::Type,
+        b2: Option<B::Type>,
+        b3: <B as DeclaredTrait>::Type,
+        b4: Option<<B as DeclaredTrait>::Type>,
+        c: C,
+        c1: C::Type,
+        c2: Option<C::Type>,
+        c3: <C as WhereTrait>::Type,
+        c4: Option<<C as WhereTrait>::Type>,
+        d: <i32 as DeclaredTrait>::Type,
+    },
+}
+
+fn main() {
+    let e: Enum<i32, i32, i32> =
+        Enum::Seq(0, None, 0, PrivateStruct(0), 0, 0, None, 0, None, 0, 0, None, 0, None, 0);
+    assert_eq!(e, e);
+
+    let e: Enum<i32, i32, i32> = Enum::Map {
+        m1: 0,
+        m2: None,
+        a1: 0,
+        a2: PrivateStruct(0),
+        b: 0,
+        b1: 0,
+        b2: None,
+        b3: 0,
+        b4: None,
+        c: 0,
+        c1: 0,
+        c2: None,
+        c3: 0,
+        c4: None,
+        d: 0,
+    };
+    assert_eq!(e, e);
+    let e: TupleStruct<i32, i32, i32> =
+        TupleStruct(0, None, 0, PrivateStruct(0), 0, 0, None, 0, None, 0, 0, None, 0, None, 0);
+    assert_eq!(e, e);
+
+    let e: Struct<i32, i32, i32> = Struct {
+        m1: 0,
+        m2: None,
+        a1: 0,
+        a2: PrivateStruct(0),
+        b: 0,
+        b1: 0,
+        b2: None,
+        b3: 0,
+        b4: None,
+        c: 0,
+        c1: 0,
+        c2: None,
+        c3: 0,
+        c4: None,
+        d: 0,
+    };
+    assert_eq!(e, e);
+
+    let e = Enum::Unit::<i32, i32, i32>;
+    assert_eq!(e, e);
+}
diff --git a/src/tools/miri/tests/pass/disable-alignment-check.rs b/src/tools/miri/tests/pass/disable-alignment-check.rs
new file mode 100644
index 000000000000..366aff4a9f8e
--- /dev/null
+++ b/src/tools/miri/tests/pass/disable-alignment-check.rs
@@ -0,0 +1,11 @@
+//@compile-flags: -Zmiri-disable-alignment-check
+
+fn main() {
+    let mut x = [0u8; 20];
+    let x_ptr: *mut u8 = x.as_mut_ptr();
+    // At least one of these is definitely unaligned.
+    unsafe {
+        *(x_ptr as *mut u64) = 42;
+        *(x_ptr.add(1) as *mut u64) = 42;
+    }
+}
diff --git a/src/tools/miri/tests/pass/drop_empty_slice.rs b/src/tools/miri/tests/pass/drop_empty_slice.rs
new file mode 100644
index 000000000000..9805ce0ace3f
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_empty_slice.rs
@@ -0,0 +1,7 @@
+#![feature(box_syntax)]
+
+fn main() {
+    // With the nested Vec, this is calling Offset(Unique::empty(), 0) on drop.
+    let args: Vec<Vec<i32>> = Vec::new();
+    let _val = box args;
+}
diff --git a/src/tools/miri/tests/pass/drop_on_array_elements.rs b/src/tools/miri/tests/pass/drop_on_array_elements.rs
new file mode 100644
index 000000000000..ae1ef036267e
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_on_array_elements.rs
@@ -0,0 +1,24 @@
+struct Bar(u16); // ZSTs are tested separately
+
+static mut DROP_COUNT: usize = 0;
+
+impl Drop for Bar {
+    fn drop(&mut self) {
+        assert_eq!(self.0 as usize, unsafe { DROP_COUNT }); // tests whether we are called at a valid address
+        unsafe {
+            DROP_COUNT += 1;
+        }
+    }
+}
+
+fn main() {
+    let b = [Bar(0), Bar(1), Bar(2), Bar(3)];
+    assert_eq!(unsafe { DROP_COUNT }, 0);
+    drop(b);
+    assert_eq!(unsafe { DROP_COUNT }, 4);
+
+    // check empty case
+    let b: [Bar; 0] = [];
+    drop(b);
+    assert_eq!(unsafe { DROP_COUNT }, 4);
+}
diff --git a/src/tools/miri/tests/pass/drop_on_fat_ptr_array_elements.rs b/src/tools/miri/tests/pass/drop_on_fat_ptr_array_elements.rs
new file mode 100644
index 000000000000..40025cd07f7e
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_on_fat_ptr_array_elements.rs
@@ -0,0 +1,22 @@
+trait Foo {}
+
+struct Bar;
+
+impl Foo for Bar {}
+
+static mut DROP_COUNT: usize = 0;
+
+impl Drop for Bar {
+    fn drop(&mut self) {
+        unsafe {
+            DROP_COUNT += 1;
+        }
+    }
+}
+
+fn main() {
+    let b: [Box<dyn Foo>; 4] = [Box::new(Bar), Box::new(Bar), Box::new(Bar), Box::new(Bar)];
+    assert_eq!(unsafe { DROP_COUNT }, 0);
+    drop(b);
+    assert_eq!(unsafe { DROP_COUNT }, 4);
+}
diff --git a/src/tools/miri/tests/pass/drop_on_zst_array_elements.rs b/src/tools/miri/tests/pass/drop_on_zst_array_elements.rs
new file mode 100644
index 000000000000..babe098e4e6f
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_on_zst_array_elements.rs
@@ -0,0 +1,23 @@
+struct Bar;
+
+static mut DROP_COUNT: usize = 0;
+
+impl Drop for Bar {
+    fn drop(&mut self) {
+        unsafe {
+            DROP_COUNT += 1;
+        }
+    }
+}
+
+fn main() {
+    let b = [Bar, Bar, Bar, Bar];
+    assert_eq!(unsafe { DROP_COUNT }, 0);
+    drop(b);
+    assert_eq!(unsafe { DROP_COUNT }, 4);
+
+    // check empty case
+    let b: [Bar; 0] = [];
+    drop(b);
+    assert_eq!(unsafe { DROP_COUNT }, 4);
+}
diff --git a/src/tools/miri/tests/pass/drop_through_owned_slice.rs b/src/tools/miri/tests/pass/drop_through_owned_slice.rs
new file mode 100644
index 000000000000..8cdeb57d02f7
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_through_owned_slice.rs
@@ -0,0 +1,18 @@
+struct Bar;
+
+static mut DROP_COUNT: usize = 0;
+
+impl Drop for Bar {
+    fn drop(&mut self) {
+        unsafe {
+            DROP_COUNT += 1;
+        }
+    }
+}
+
+fn main() {
+    let b: Box<[Bar]> = vec![Bar, Bar, Bar, Bar].into_boxed_slice();
+    assert_eq!(unsafe { DROP_COUNT }, 0);
+    drop(b);
+    assert_eq!(unsafe { DROP_COUNT }, 4);
+}
diff --git a/src/tools/miri/tests/pass/drop_through_trait_object.rs b/src/tools/miri/tests/pass/drop_through_trait_object.rs
new file mode 100644
index 000000000000..8d22ca9ceb4a
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_through_trait_object.rs
@@ -0,0 +1,22 @@
+trait Foo {}
+
+struct Bar;
+
+static mut DROP_CALLED: bool = false;
+
+impl Drop for Bar {
+    fn drop(&mut self) {
+        unsafe {
+            DROP_CALLED = true;
+        }
+    }
+}
+
+impl Foo for Bar {}
+
+fn main() {
+    let b: Box<dyn Foo> = Box::new(Bar);
+    assert!(unsafe { !DROP_CALLED });
+    drop(b);
+    assert!(unsafe { DROP_CALLED });
+}
diff --git a/src/tools/miri/tests/pass/drop_through_trait_object_rc.rs b/src/tools/miri/tests/pass/drop_through_trait_object_rc.rs
new file mode 100644
index 000000000000..7806c0252d27
--- /dev/null
+++ b/src/tools/miri/tests/pass/drop_through_trait_object_rc.rs
@@ -0,0 +1,24 @@
+trait Foo {}
+
+struct Bar;
+
+static mut DROP_CALLED: bool = false;
+
+impl Drop for Bar {
+    fn drop(&mut self) {
+        unsafe {
+            DROP_CALLED = true;
+        }
+    }
+}
+
+impl Foo for Bar {}
+
+use std::rc::Rc;
+
+fn main() {
+    let b: Rc<dyn Foo> = Rc::new(Bar);
+    assert!(unsafe { !DROP_CALLED });
+    drop(b);
+    assert!(unsafe { DROP_CALLED });
+}
diff --git a/src/tools/miri/tests/pass/dst-field-align.rs b/src/tools/miri/tests/pass/dst-field-align.rs
new file mode 100644
index 000000000000..4d1db03643f7
--- /dev/null
+++ b/src/tools/miri/tests/pass/dst-field-align.rs
@@ -0,0 +1,66 @@
+#[allow(dead_code)]
+struct Foo<T: ?Sized> {
+    a: u16,
+    b: T,
+}
+
+trait Bar {
+    fn get(&self) -> usize;
+}
+
+impl Bar for usize {
+    fn get(&self) -> usize {
+        *self
+    }
+}
+
+struct Baz<T: ?Sized> {
+    a: T,
+}
+
+#[allow(dead_code)]
+struct HasDrop<T: ?Sized> {
+    ptr: Box<usize>,
+    data: T,
+}
+
+fn main() {
+    // Test that zero-offset works properly
+    let b: Baz<usize> = Baz { a: 7 };
+    assert_eq!(b.a.get(), 7);
+    let b: &Baz<dyn Bar> = &b;
+    assert_eq!(b.a.get(), 7);
+
+    // Test that the field is aligned properly
+    let f: Foo<usize> = Foo { a: 0, b: 11 };
+    assert_eq!(f.b.get(), 11);
+    let ptr1: *const u8 = &f.b as *const _ as *const u8;
+
+    let f: &Foo<dyn Bar> = &f;
+    let ptr2: *const u8 = &f.b as *const _ as *const u8;
+    assert_eq!(f.b.get(), 11);
+
+    // The pointers should be the same
+    assert_eq!(ptr1, ptr2);
+
+    // Test that nested DSTs work properly
+    let f: Foo<Foo<usize>> = Foo { a: 0, b: Foo { a: 1, b: 17 } };
+    assert_eq!(f.b.b.get(), 17);
+    let f: &Foo<Foo<dyn Bar>> = &f;
+    assert_eq!(f.b.b.get(), 17);
+
+    // Test that get the pointer via destructuring works
+
+    let f: Foo<usize> = Foo { a: 0, b: 11 };
+    let f: &Foo<dyn Bar> = &f;
+    let &Foo { a: _, b: ref bar } = f;
+    assert_eq!(bar.get(), 11);
+
+    // Make sure that drop flags don't screw things up
+
+    let d: HasDrop<Baz<[i32; 4]>> = HasDrop { ptr: Box::new(0), data: Baz { a: [1, 2, 3, 4] } };
+    assert_eq!([1, 2, 3, 4], d.data.a);
+
+    let d: &HasDrop<Baz<[i32]>> = &d;
+    assert_eq!(&[1, 2, 3, 4], &d.data.a);
+}
diff --git a/src/tools/miri/tests/pass/dst-irrefutable-bind.rs b/src/tools/miri/tests/pass/dst-irrefutable-bind.rs
new file mode 100644
index 000000000000..fe7335c0c656
--- /dev/null
+++ b/src/tools/miri/tests/pass/dst-irrefutable-bind.rs
@@ -0,0 +1,14 @@
+struct Test<T: ?Sized>(T);
+
+fn main() {
+    let x = Test([1, 2, 3]);
+    let x: &Test<[i32]> = &x;
+
+    let &ref _y = x;
+
+    // Make sure binding to a fat pointer behind a reference
+    // still works
+    let slice = &[1, 2, 3];
+    let x = Test(&slice);
+    let Test(&_slice) = x;
+}
diff --git a/src/tools/miri/tests/pass/dst-raw.rs b/src/tools/miri/tests/pass/dst-raw.rs
new file mode 100644
index 000000000000..f26191a1d599
--- /dev/null
+++ b/src/tools/miri/tests/pass/dst-raw.rs
@@ -0,0 +1,94 @@
+// Test DST raw pointers
+
+trait Trait {
+    fn foo(&self) -> isize;
+}
+
+struct A {
+    f: isize,
+}
+impl Trait for A {
+    fn foo(&self) -> isize {
+        self.f
+    }
+}
+
+struct Foo<T: ?Sized> {
+    f: T,
+}
+
+pub fn main() {
+    // raw trait object
+    let x = A { f: 42 };
+    let z: *const dyn Trait = &x;
+    let r = unsafe { (&*z).foo() };
+    assert_eq!(r, 42);
+
+    // raw DST struct
+    let p = Foo { f: A { f: 42 } };
+    let o: *const Foo<dyn Trait> = &p;
+    let r = unsafe { (&*o).f.foo() };
+    assert_eq!(r, 42);
+
+    // raw slice
+    let a: *const [_] = &[1, 2, 3];
+    unsafe {
+        let b = (*a)[2];
+        assert_eq!(b, 3);
+        let len = (*a).len();
+        assert_eq!(len, 3);
+    }
+
+    // raw slice with explicit cast
+    let a = &[1, 2, 3] as *const [i32];
+    unsafe {
+        let b = (*a)[2];
+        assert_eq!(b, 3);
+        let len = (*a).len();
+        assert_eq!(len, 3);
+    }
+
+    // raw DST struct with slice
+    let c: *const Foo<[_]> = &Foo { f: [1, 2, 3] };
+    unsafe {
+        let b = (&*c).f[0];
+        assert_eq!(b, 1);
+        let len = (&*c).f.len();
+        assert_eq!(len, 3);
+    }
+
+    // all of the above with *mut
+    let mut x = A { f: 42 };
+    let z: *mut dyn Trait = &mut x;
+    let r = unsafe { (&*z).foo() };
+    assert_eq!(r, 42);
+
+    let mut p = Foo { f: A { f: 42 } };
+    let o: *mut Foo<dyn Trait> = &mut p;
+    let r = unsafe { (&*o).f.foo() };
+    assert_eq!(r, 42);
+
+    let a: *mut [_] = &mut [1, 2, 3];
+    unsafe {
+        let b = (*a)[2];
+        assert_eq!(b, 3);
+        let len = (*a).len();
+        assert_eq!(len, 3);
+    }
+
+    let a = &mut [1, 2, 3] as *mut [i32];
+    unsafe {
+        let b = (*a)[2];
+        assert_eq!(b, 3);
+        let len = (*a).len();
+        assert_eq!(len, 3);
+    }
+
+    let c: *mut Foo<[_]> = &mut Foo { f: [1, 2, 3] };
+    unsafe {
+        let b = (&*c).f[0];
+        assert_eq!(b, 1);
+        let len = (&*c).f.len();
+        assert_eq!(len, 3);
+    }
+}
diff --git a/src/tools/miri/tests/pass/dst-struct-sole.rs b/src/tools/miri/tests/pass/dst-struct-sole.rs
new file mode 100644
index 000000000000..4b25fbb06300
--- /dev/null
+++ b/src/tools/miri/tests/pass/dst-struct-sole.rs
@@ -0,0 +1,74 @@
+// As dst-struct.rs, but the unsized field is the only field in the struct.
+
+struct Fat<T: ?Sized> {
+    ptr: T,
+}
+
+// x is a fat pointer
+fn foo(x: &Fat<[isize]>) {
+    let y = &x.ptr;
+    assert_eq!(x.ptr.len(), 3);
+    assert_eq!(y[0], 1);
+    assert_eq!(x.ptr[1], 2);
+}
+
+fn foo2<T: ToBar>(x: &Fat<[T]>) {
+    let y = &x.ptr;
+    let bar = Bar;
+    assert_eq!(x.ptr.len(), 3);
+    assert_eq!(y[0].to_bar(), bar);
+    assert_eq!(x.ptr[1].to_bar(), bar);
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+struct Bar;
+
+trait ToBar {
+    fn to_bar(&self) -> Bar;
+}
+
+impl ToBar for Bar {
+    fn to_bar(&self) -> Bar {
+        *self
+    }
+}
+
+pub fn main() {
+    // With a vec of ints.
+    let f1 = Fat { ptr: [1, 2, 3] };
+    foo(&f1);
+    let f2 = &f1;
+    foo(f2);
+    let f3: &Fat<[isize]> = f2;
+    foo(f3);
+    let f4: &Fat<[isize]> = &f1;
+    foo(f4);
+    let f5: &Fat<[isize]> = &Fat { ptr: [1, 2, 3] };
+    foo(f5);
+
+    // With a vec of Bars.
+    let bar = Bar;
+    let f1 = Fat { ptr: [bar, bar, bar] };
+    foo2(&f1);
+    let f2 = &f1;
+    foo2(f2);
+    let f3: &Fat<[Bar]> = f2;
+    foo2(f3);
+    let f4: &Fat<[Bar]> = &f1;
+    foo2(f4);
+    let f5: &Fat<[Bar]> = &Fat { ptr: [bar, bar, bar] };
+    foo2(f5);
+
+    // Assignment.
+    let f5: &mut Fat<[isize]> = &mut Fat { ptr: [1, 2, 3] };
+    f5.ptr[1] = 34;
+    assert_eq!(f5.ptr[0], 1);
+    assert_eq!(f5.ptr[1], 34);
+    assert_eq!(f5.ptr[2], 3);
+
+    // Zero size vec.
+    let f5: &Fat<[isize]> = &Fat { ptr: [] };
+    assert!(f5.ptr.is_empty());
+    let f5: &Fat<[Bar]> = &Fat { ptr: [] };
+    assert!(f5.ptr.is_empty());
+}
diff --git a/src/tools/miri/tests/pass/dst-struct.rs b/src/tools/miri/tests/pass/dst-struct.rs
new file mode 100644
index 000000000000..7191068eb2c4
--- /dev/null
+++ b/src/tools/miri/tests/pass/dst-struct.rs
@@ -0,0 +1,122 @@
+#![feature(box_syntax)]
+
+struct Fat<T: ?Sized> {
+    f1: isize,
+    f2: &'static str,
+    ptr: T,
+}
+
+// x is a fat pointer
+fn foo(x: &Fat<[isize]>) {
+    let y = &x.ptr;
+    assert_eq!(x.ptr.len(), 3);
+    assert_eq!(y[0], 1);
+    assert_eq!(x.ptr[1], 2);
+    assert_eq!(x.f1, 5);
+    assert_eq!(x.f2, "some str");
+}
+
+fn foo2<T: ToBar>(x: &Fat<[T]>) {
+    let y = &x.ptr;
+    let bar = Bar;
+    assert_eq!(x.ptr.len(), 3);
+    assert_eq!(y[0].to_bar(), bar);
+    assert_eq!(x.ptr[1].to_bar(), bar);
+    assert_eq!(x.f1, 5);
+    assert_eq!(x.f2, "some str");
+}
+
+fn foo3(x: &Fat<Fat<[isize]>>) {
+    let y = &x.ptr.ptr;
+    assert_eq!(x.f1, 5);
+    assert_eq!(x.f2, "some str");
+    assert_eq!(x.ptr.f1, 8);
+    assert_eq!(x.ptr.f2, "deep str");
+    assert_eq!(x.ptr.ptr.len(), 3);
+    assert_eq!(y[0], 1);
+    assert_eq!(x.ptr.ptr[1], 2);
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+struct Bar;
+
+trait ToBar {
+    fn to_bar(&self) -> Bar;
+}
+
+impl ToBar for Bar {
+    fn to_bar(&self) -> Bar {
+        *self
+    }
+}
+
+pub fn main() {
+    // With a vec of ints.
+    let f1: Fat<[isize; 3]> = Fat { f1: 5, f2: "some str", ptr: [1, 2, 3] };
+    foo(&f1);
+    let f2: &Fat<[isize; 3]> = &f1;
+    foo(f2);
+    let f3: &Fat<[isize]> = f2;
+    foo(f3);
+    let f4: &Fat<[isize]> = &f1;
+    foo(f4);
+    let f5: &Fat<[isize]> = &Fat { f1: 5, f2: "some str", ptr: [1, 2, 3] };
+    foo(f5);
+
+    // With a vec of Bars.
+    let bar = Bar;
+    let f1 = Fat { f1: 5, f2: "some str", ptr: [bar, bar, bar] };
+    foo2(&f1);
+    let f2 = &f1;
+    foo2(f2);
+    let f3: &Fat<[Bar]> = f2;
+    foo2(f3);
+    let f4: &Fat<[Bar]> = &f1;
+    foo2(f4);
+    let f5: &Fat<[Bar]> = &Fat { f1: 5, f2: "some str", ptr: [bar, bar, bar] };
+    foo2(f5);
+
+    // Assignment.
+    let f5: &mut Fat<[isize]> = &mut Fat { f1: 5, f2: "some str", ptr: [1, 2, 3] };
+    f5.ptr[1] = 34;
+    assert_eq!(f5.ptr[0], 1);
+    assert_eq!(f5.ptr[1], 34);
+    assert_eq!(f5.ptr[2], 3);
+
+    // Zero size vec.
+    let f5: &Fat<[isize]> = &Fat { f1: 5, f2: "some str", ptr: [] };
+    assert!(f5.ptr.is_empty());
+    let f5: &Fat<[Bar]> = &Fat { f1: 5, f2: "some str", ptr: [] };
+    assert!(f5.ptr.is_empty());
+
+    // Deeply nested.
+    let f1 = Fat { f1: 5, f2: "some str", ptr: Fat { f1: 8, f2: "deep str", ptr: [1, 2, 3] } };
+    foo3(&f1);
+    let f2 = &f1;
+    foo3(f2);
+    let f3: &Fat<Fat<[isize]>> = f2;
+    foo3(f3);
+    let f4: &Fat<Fat<[isize]>> = &f1;
+    foo3(f4);
+    let f5: &Fat<Fat<[isize]>> =
+        &Fat { f1: 5, f2: "some str", ptr: Fat { f1: 8, f2: "deep str", ptr: [1, 2, 3] } };
+    foo3(f5);
+
+    // Box.
+    let f1 = Box::new([1, 2, 3]);
+    assert_eq!((*f1)[1], 2);
+    let f2: Box<[isize]> = f1;
+    assert_eq!((*f2)[1], 2);
+
+    // Nested Box.
+    let f1: Box<Fat<[isize; 3]>> = box Fat { f1: 5, f2: "some str", ptr: [1, 2, 3] };
+    foo(&*f1);
+    let f2: Box<Fat<[isize]>> = f1;
+    foo(&*f2);
+
+    let f3: Box<Fat<[isize]>> =
+        Box::<Fat<[_; 3]>>::new(Fat { f1: 5, f2: "some str", ptr: [1, 2, 3] });
+    foo(&*f3);
+    let f4: Box<Fat<[isize]>> = box Fat { f1: 5, f2: "some str", ptr: [1, 2, 3] };
+    foo(&*f4);
+}
diff --git a/src/tools/miri/tests/pass/dyn-arbitrary-self.rs b/src/tools/miri/tests/pass/dyn-arbitrary-self.rs
new file mode 100644
index 000000000000..256c72add922
--- /dev/null
+++ b/src/tools/miri/tests/pass/dyn-arbitrary-self.rs
@@ -0,0 +1,128 @@
+#![feature(arbitrary_self_types, unsize, coerce_unsized, dispatch_from_dyn)]
+#![feature(rustc_attrs)]
+
+fn pin_box_dyn() {
+    use std::pin::Pin;
+
+    trait Foo {
+        fn bar(self: Pin<&mut Self>) -> bool;
+    }
+
+    impl Foo for &'static str {
+        fn bar(self: Pin<&mut Self>) -> bool {
+            true
+        }
+    }
+
+    let mut test: Pin<Box<dyn Foo>> = Box::pin("foo");
+    test.as_mut().bar();
+}
+
+fn stdlib_pointers() {
+    use std::{pin::Pin, rc::Rc, sync::Arc};
+
+    trait Trait {
+        fn by_rc(self: Rc<Self>) -> i64;
+        fn by_arc(self: Arc<Self>) -> i64;
+        fn by_pin_mut(self: Pin<&mut Self>) -> i64;
+        fn by_pin_box(self: Pin<Box<Self>>) -> i64;
+    }
+
+    impl Trait for i64 {
+        fn by_rc(self: Rc<Self>) -> i64 {
+            *self
+        }
+        fn by_arc(self: Arc<Self>) -> i64 {
+            *self
+        }
+        fn by_pin_mut(self: Pin<&mut Self>) -> i64 {
+            *self
+        }
+        fn by_pin_box(self: Pin<Box<Self>>) -> i64 {
+            *self
+        }
+    }
+
+    let rc = Rc::new(1i64) as Rc<dyn Trait>;
+    assert_eq!(1, rc.by_rc());
+
+    let arc = Arc::new(2i64) as Arc<dyn Trait>;
+    assert_eq!(2, arc.by_arc());
+
+    let mut value = 3i64;
+    let pin_mut = Pin::new(&mut value) as Pin<&mut dyn Trait>;
+    assert_eq!(3, pin_mut.by_pin_mut());
+
+    let pin_box = Into::<Pin<Box<i64>>>::into(Box::new(4i64)) as Pin<Box<dyn Trait>>;
+    assert_eq!(4, pin_box.by_pin_box());
+}
+
+fn pointers_and_wrappers() {
+    use std::{
+        marker::Unsize,
+        ops::{CoerceUnsized, Deref, DispatchFromDyn},
+    };
+
+    struct Ptr<T: ?Sized>(Box<T>);
+
+    impl<T: ?Sized> Deref for Ptr<T> {
+        type Target = T;
+
+        fn deref(&self) -> &T {
+            &*self.0
+        }
+    }
+
+    impl<T: Unsize<U> + ?Sized, U: ?Sized> CoerceUnsized<Ptr<U>> for Ptr<T> {}
+    impl<T: Unsize<U> + ?Sized, U: ?Sized> DispatchFromDyn<Ptr<U>> for Ptr<T> {}
+
+    struct Wrapper<T: ?Sized>(T);
+
+    impl<T: ?Sized> Deref for Wrapper<T> {
+        type Target = T;
+
+        fn deref(&self) -> &T {
+            &self.0
+        }
+    }
+
+    impl<T: CoerceUnsized<U>, U> CoerceUnsized<Wrapper<U>> for Wrapper<T> {}
+    impl<T: DispatchFromDyn<U>, U> DispatchFromDyn<Wrapper<U>> for Wrapper<T> {}
+
+    trait Trait {
+        // This method isn't object-safe yet. Unsized by-value `self` is object-safe (but not callable
+        // without unsized_locals), but wrappers arond `Self` currently are not.
+        // FIXME (mikeyhew) uncomment this when unsized rvalues object-safety is implemented
+        // fn wrapper(self: Wrapper<Self>) -> i32;
+        fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32;
+        fn wrapper_ptr(self: Wrapper<Ptr<Self>>) -> i32;
+        fn wrapper_ptr_wrapper(self: Wrapper<Ptr<Wrapper<Self>>>) -> i32;
+    }
+
+    impl Trait for i32 {
+        fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32 {
+            **self
+        }
+        fn wrapper_ptr(self: Wrapper<Ptr<Self>>) -> i32 {
+            **self
+        }
+        fn wrapper_ptr_wrapper(self: Wrapper<Ptr<Wrapper<Self>>>) -> i32 {
+            ***self
+        }
+    }
+
+    let pw = Ptr(Box::new(Wrapper(5))) as Ptr<Wrapper<dyn Trait>>;
+    assert_eq!(pw.ptr_wrapper(), 5);
+
+    let wp = Wrapper(Ptr(Box::new(6))) as Wrapper<Ptr<dyn Trait>>;
+    assert_eq!(wp.wrapper_ptr(), 6);
+
+    let wpw = Wrapper(Ptr(Box::new(Wrapper(7)))) as Wrapper<Ptr<Wrapper<dyn Trait>>>;
+    assert_eq!(wpw.wrapper_ptr_wrapper(), 7);
+}
+
+fn main() {
+    pin_box_dyn();
+    stdlib_pointers();
+    pointers_and_wrappers();
+}
diff --git a/src/tools/miri/tests/pass/dyn-traits.rs b/src/tools/miri/tests/pass/dyn-traits.rs
new file mode 100644
index 000000000000..908d521a0d81
--- /dev/null
+++ b/src/tools/miri/tests/pass/dyn-traits.rs
@@ -0,0 +1,147 @@
+fn ref_box_dyn() {
+    struct Struct(i32);
+
+    trait Trait {
+        fn method(&self);
+
+        fn box_method(self: Box<Self>);
+    }
+
+    impl Trait for Struct {
+        fn method(&self) {
+            assert_eq!(self.0, 42);
+        }
+
+        fn box_method(self: Box<Self>) {
+            assert_eq!(self.0, 7);
+        }
+    }
+
+    struct Foo<T: ?Sized>(T);
+
+    let y: &dyn Trait = &Struct(42);
+    y.method();
+
+    let x: Foo<Struct> = Foo(Struct(42));
+    let y: &Foo<dyn Trait> = &x;
+    y.0.method();
+
+    let y: Box<dyn Trait> = Box::new(Struct(42));
+    y.method();
+
+    let y = &y;
+    y.method();
+
+    let y: Box<dyn Trait> = Box::new(Struct(7));
+    y.box_method();
+}
+
+fn box_box_trait() {
+    struct DroppableStruct;
+
+    static mut DROPPED: bool = false;
+
+    impl Drop for DroppableStruct {
+        fn drop(&mut self) {
+            unsafe {
+                DROPPED = true;
+            }
+        }
+    }
+
+    trait MyTrait {
+        fn dummy(&self) {}
+    }
+    impl MyTrait for Box<DroppableStruct> {}
+
+    struct Whatever {
+        w: Box<dyn MyTrait + 'static>,
+    }
+
+    impl Whatever {
+        fn new(w: Box<dyn MyTrait + 'static>) -> Whatever {
+            Whatever { w: w }
+        }
+    }
+
+    {
+        let f = Box::new(DroppableStruct);
+        let a = Whatever::new(Box::new(f) as Box<dyn MyTrait>);
+        a.w.dummy();
+    }
+    assert!(unsafe { DROPPED });
+}
+
+// Disabled for now: unsized locals are not supported,
+// their current MIR encoding is just not great.
+/*
+fn unsized_dyn() {
+    pub trait Foo {
+        fn foo(self) -> String;
+    }
+
+    struct A;
+
+    impl Foo for A {
+        fn foo(self) -> String {
+            format!("hello")
+        }
+    }
+
+    let x = *(Box::new(A) as Box<dyn Foo>);
+    assert_eq!(x.foo(), format!("hello"));
+
+    // I'm not sure whether we want this to work
+    let x = Box::new(A) as Box<dyn Foo>;
+    assert_eq!(x.foo(), format!("hello"));
+}
+fn unsized_dyn_autoderef() {
+    pub trait Foo {
+        fn foo(self) -> String;
+    }
+
+    impl Foo for [char] {
+        fn foo(self) -> String {
+            self.iter().collect()
+        }
+    }
+
+    impl Foo for str {
+        fn foo(self) -> String {
+            self.to_owned()
+        }
+    }
+
+    impl Foo for dyn FnMut() -> String {
+        fn foo(mut self) -> String {
+            self()
+        }
+    }
+
+    let x = *(Box::new(['h', 'e', 'l', 'l', 'o']) as Box<[char]>);
+    assert_eq!(&x.foo() as &str, "hello");
+
+    let x = Box::new(['h', 'e', 'l', 'l', 'o']) as Box<[char]>;
+    assert_eq!(&x.foo() as &str, "hello");
+
+    let x = "hello".to_owned().into_boxed_str();
+    assert_eq!(&x.foo() as &str, "hello");
+
+    let x = *("hello".to_owned().into_boxed_str());
+    assert_eq!(&x.foo() as &str, "hello");
+
+    let x = "hello".to_owned().into_boxed_str();
+    assert_eq!(&x.foo() as &str, "hello");
+
+    let x = *(Box::new(|| "hello".to_owned()) as Box<dyn FnMut() -> String>);
+    assert_eq!(&x.foo() as &str, "hello");
+
+    let x = Box::new(|| "hello".to_owned()) as Box<dyn FnMut() -> String>;
+    assert_eq!(&x.foo() as &str, "hello");
+}
+*/
+
+fn main() {
+    ref_box_dyn();
+    box_box_trait();
+}
diff --git a/src/tools/miri/tests/pass/dyn-upcast.rs b/src/tools/miri/tests/pass/dyn-upcast.rs
new file mode 100644
index 000000000000..8432012a9ba5
--- /dev/null
+++ b/src/tools/miri/tests/pass/dyn-upcast.rs
@@ -0,0 +1,427 @@
+#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
+
+fn main() {
+    basic();
+    diamond();
+    struct_();
+    replace_vptr();
+    vtable_mismatch_nop_cast();
+}
+
+fn vtable_mismatch_nop_cast() {
+    let ptr: &dyn std::fmt::Display = &0;
+    // Even though the vtable is for the wrong trait, this cast doesn't actually change the needed
+    // vtable so it should still be allowed.
+    let ptr: *const (dyn std::fmt::Debug + Send + Sync) = unsafe { std::mem::transmute(ptr) };
+    let _ptr2 = ptr as *const dyn std::fmt::Debug;
+}
+
+fn basic() {
+    trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
+        fn a(&self) -> i32 {
+            10
+        }
+
+        fn z(&self) -> i32 {
+            11
+        }
+
+        fn y(&self) -> i32 {
+            12
+        }
+    }
+
+    trait Bar: Foo {
+        fn b(&self) -> i32 {
+            20
+        }
+
+        fn w(&self) -> i32 {
+            21
+        }
+    }
+
+    trait Baz: Bar {
+        fn c(&self) -> i32 {
+            30
+        }
+    }
+
+    impl Foo for i32 {
+        fn a(&self) -> i32 {
+            100
+        }
+    }
+
+    impl Bar for i32 {
+        fn b(&self) -> i32 {
+            200
+        }
+    }
+
+    impl Baz for i32 {
+        fn c(&self) -> i32 {
+            300
+        }
+    }
+
+    let baz: &dyn Baz = &1;
+    let _: &dyn std::fmt::Debug = baz;
+    assert_eq!(*baz, 1);
+    assert_eq!(baz.a(), 100);
+    assert_eq!(baz.b(), 200);
+    assert_eq!(baz.c(), 300);
+    assert_eq!(baz.z(), 11);
+    assert_eq!(baz.y(), 12);
+    assert_eq!(baz.w(), 21);
+
+    let bar: &dyn Bar = baz;
+    let _: &dyn std::fmt::Debug = bar;
+    assert_eq!(*bar, 1);
+    assert_eq!(bar.a(), 100);
+    assert_eq!(bar.b(), 200);
+    assert_eq!(bar.z(), 11);
+    assert_eq!(bar.y(), 12);
+    assert_eq!(bar.w(), 21);
+
+    let foo: &dyn Foo = baz;
+    let _: &dyn std::fmt::Debug = foo;
+    assert_eq!(*foo, 1);
+    assert_eq!(foo.a(), 100);
+    assert_eq!(foo.z(), 11);
+    assert_eq!(foo.y(), 12);
+
+    let foo: &dyn Foo = bar;
+    let _: &dyn std::fmt::Debug = foo;
+    assert_eq!(*foo, 1);
+    assert_eq!(foo.a(), 100);
+    assert_eq!(foo.z(), 11);
+    assert_eq!(foo.y(), 12);
+}
+
+fn diamond() {
+    trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
+        fn a(&self) -> i32 {
+            10
+        }
+
+        fn z(&self) -> i32 {
+            11
+        }
+
+        fn y(&self) -> i32 {
+            12
+        }
+    }
+
+    trait Bar1: Foo {
+        fn b(&self) -> i32 {
+            20
+        }
+
+        fn w(&self) -> i32 {
+            21
+        }
+    }
+
+    trait Bar2: Foo {
+        fn c(&self) -> i32 {
+            30
+        }
+
+        fn v(&self) -> i32 {
+            31
+        }
+    }
+
+    trait Baz: Bar1 + Bar2 {
+        fn d(&self) -> i32 {
+            40
+        }
+    }
+
+    impl Foo for i32 {
+        fn a(&self) -> i32 {
+            100
+        }
+    }
+
+    impl Bar1 for i32 {
+        fn b(&self) -> i32 {
+            200
+        }
+    }
+
+    impl Bar2 for i32 {
+        fn c(&self) -> i32 {
+            300
+        }
+    }
+
+    impl Baz for i32 {
+        fn d(&self) -> i32 {
+            400
+        }
+    }
+
+    let baz: &dyn Baz = &1;
+    let _: &dyn std::fmt::Debug = baz;
+    assert_eq!(*baz, 1);
+    assert_eq!(baz.a(), 100);
+    assert_eq!(baz.b(), 200);
+    assert_eq!(baz.c(), 300);
+    assert_eq!(baz.d(), 400);
+    assert_eq!(baz.z(), 11);
+    assert_eq!(baz.y(), 12);
+    assert_eq!(baz.w(), 21);
+    assert_eq!(baz.v(), 31);
+
+    let bar1: &dyn Bar1 = baz;
+    let _: &dyn std::fmt::Debug = bar1;
+    assert_eq!(*bar1, 1);
+    assert_eq!(bar1.a(), 100);
+    assert_eq!(bar1.b(), 200);
+    assert_eq!(bar1.z(), 11);
+    assert_eq!(bar1.y(), 12);
+    assert_eq!(bar1.w(), 21);
+
+    let bar2: &dyn Bar2 = baz;
+    let _: &dyn std::fmt::Debug = bar2;
+    assert_eq!(*bar2, 1);
+    assert_eq!(bar2.a(), 100);
+    assert_eq!(bar2.c(), 300);
+    assert_eq!(bar2.z(), 11);
+    assert_eq!(bar2.y(), 12);
+    assert_eq!(bar2.v(), 31);
+
+    let foo: &dyn Foo = baz;
+    let _: &dyn std::fmt::Debug = foo;
+    assert_eq!(*foo, 1);
+    assert_eq!(foo.a(), 100);
+
+    let foo: &dyn Foo = bar1;
+    let _: &dyn std::fmt::Debug = foo;
+    assert_eq!(*foo, 1);
+    assert_eq!(foo.a(), 100);
+
+    let foo: &dyn Foo = bar2;
+    let _: &dyn std::fmt::Debug = foo;
+    assert_eq!(*foo, 1);
+    assert_eq!(foo.a(), 100);
+}
+
+fn struct_() {
+    use std::rc::Rc;
+    use std::sync::Arc;
+
+    trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
+        fn a(&self) -> i32 {
+            10
+        }
+
+        fn z(&self) -> i32 {
+            11
+        }
+
+        fn y(&self) -> i32 {
+            12
+        }
+    }
+
+    trait Bar: Foo {
+        fn b(&self) -> i32 {
+            20
+        }
+
+        fn w(&self) -> i32 {
+            21
+        }
+    }
+
+    trait Baz: Bar {
+        fn c(&self) -> i32 {
+            30
+        }
+    }
+
+    impl Foo for i32 {
+        fn a(&self) -> i32 {
+            100
+        }
+    }
+
+    impl Bar for i32 {
+        fn b(&self) -> i32 {
+            200
+        }
+    }
+
+    impl Baz for i32 {
+        fn c(&self) -> i32 {
+            300
+        }
+    }
+
+    fn test_box() {
+        let v = Box::new(1);
+
+        let baz: Box<dyn Baz> = v.clone();
+        assert_eq!(*baz, 1);
+        assert_eq!(baz.a(), 100);
+        assert_eq!(baz.b(), 200);
+        assert_eq!(baz.c(), 300);
+        assert_eq!(baz.z(), 11);
+        assert_eq!(baz.y(), 12);
+        assert_eq!(baz.w(), 21);
+
+        let baz: Box<dyn Baz> = v.clone();
+        let bar: Box<dyn Bar> = baz;
+        assert_eq!(*bar, 1);
+        assert_eq!(bar.a(), 100);
+        assert_eq!(bar.b(), 200);
+        assert_eq!(bar.z(), 11);
+        assert_eq!(bar.y(), 12);
+        assert_eq!(bar.w(), 21);
+
+        let baz: Box<dyn Baz> = v.clone();
+        let foo: Box<dyn Foo> = baz;
+        assert_eq!(*foo, 1);
+        assert_eq!(foo.a(), 100);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+
+        let baz: Box<dyn Baz> = v.clone();
+        let bar: Box<dyn Bar> = baz;
+        let foo: Box<dyn Foo> = bar;
+        assert_eq!(*foo, 1);
+        assert_eq!(foo.a(), 100);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+    }
+
+    fn test_rc() {
+        let v = Rc::new(1);
+
+        let baz: Rc<dyn Baz> = v.clone();
+        assert_eq!(*baz, 1);
+        assert_eq!(baz.a(), 100);
+        assert_eq!(baz.b(), 200);
+        assert_eq!(baz.c(), 300);
+        assert_eq!(baz.z(), 11);
+        assert_eq!(baz.y(), 12);
+        assert_eq!(baz.w(), 21);
+
+        let baz: Rc<dyn Baz> = v.clone();
+        let bar: Rc<dyn Bar> = baz;
+        assert_eq!(*bar, 1);
+        assert_eq!(bar.a(), 100);
+        assert_eq!(bar.b(), 200);
+        assert_eq!(bar.z(), 11);
+        assert_eq!(bar.y(), 12);
+        assert_eq!(bar.w(), 21);
+
+        let baz: Rc<dyn Baz> = v.clone();
+        let foo: Rc<dyn Foo> = baz;
+        assert_eq!(*foo, 1);
+        assert_eq!(foo.a(), 100);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+
+        let baz: Rc<dyn Baz> = v.clone();
+        let bar: Rc<dyn Bar> = baz;
+        let foo: Rc<dyn Foo> = bar;
+        assert_eq!(*foo, 1);
+        assert_eq!(foo.a(), 100);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+    }
+
+    fn test_arc() {
+        let v = Arc::new(1);
+
+        let baz: Arc<dyn Baz> = v.clone();
+        assert_eq!(*baz, 1);
+        assert_eq!(baz.a(), 100);
+        assert_eq!(baz.b(), 200);
+        assert_eq!(baz.c(), 300);
+        assert_eq!(baz.z(), 11);
+        assert_eq!(baz.y(), 12);
+        assert_eq!(baz.w(), 21);
+
+        let baz: Arc<dyn Baz> = v.clone();
+        let bar: Arc<dyn Bar> = baz;
+        assert_eq!(*bar, 1);
+        assert_eq!(bar.a(), 100);
+        assert_eq!(bar.b(), 200);
+        assert_eq!(bar.z(), 11);
+        assert_eq!(bar.y(), 12);
+        assert_eq!(bar.w(), 21);
+
+        let baz: Arc<dyn Baz> = v.clone();
+        let foo: Arc<dyn Foo> = baz;
+        assert_eq!(*foo, 1);
+        assert_eq!(foo.a(), 100);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+
+        let baz: Arc<dyn Baz> = v.clone();
+        let bar: Arc<dyn Bar> = baz;
+        let foo: Arc<dyn Foo> = bar;
+        assert_eq!(*foo, 1);
+        assert_eq!(foo.a(), 100);
+        assert_eq!(foo.z(), 11);
+        assert_eq!(foo.y(), 12);
+    }
+
+    test_box();
+    test_rc();
+    test_arc();
+}
+
+fn replace_vptr() {
+    trait A {
+        fn foo_a(&self);
+    }
+
+    trait B {
+        fn foo_b(&self);
+    }
+
+    trait C: A + B {
+        fn foo_c(&self);
+    }
+
+    struct S(i32);
+
+    impl A for S {
+        fn foo_a(&self) {
+            unreachable!();
+        }
+    }
+
+    impl B for S {
+        fn foo_b(&self) {
+            assert_eq!(42, self.0);
+        }
+    }
+
+    impl C for S {
+        fn foo_c(&self) {
+            unreachable!();
+        }
+    }
+
+    fn invoke_inner(b: &dyn B) {
+        b.foo_b();
+    }
+
+    fn invoke_outer(c: &dyn C) {
+        invoke_inner(c);
+    }
+
+    let s = S(42);
+    invoke_outer(&s);
+}
diff --git a/src/tools/miri/tests/pass/enum-nullable-const-null-with-fields.rs b/src/tools/miri/tests/pass/enum-nullable-const-null-with-fields.rs
new file mode 100644
index 000000000000..8385cc5d880c
--- /dev/null
+++ b/src/tools/miri/tests/pass/enum-nullable-const-null-with-fields.rs
@@ -0,0 +1,11 @@
+use std::result::Result;
+use std::result::Result::Ok;
+
+static C: Result<(), Box<isize>> = Ok(());
+
+// This is because of yet another bad assertion (ICE) about the null side of a nullable enum.
+// So we won't actually compile if the bug is present, but we check the value in main anyway.
+
+pub fn main() {
+    assert!(C.is_ok());
+}
diff --git a/src/tools/miri/tests/pass/enum_discriminant_ptr_value.rs b/src/tools/miri/tests/pass/enum_discriminant_ptr_value.rs
new file mode 100644
index 000000000000..4a3820777cff
--- /dev/null
+++ b/src/tools/miri/tests/pass/enum_discriminant_ptr_value.rs
@@ -0,0 +1,9 @@
+// A niche-optimized enum where the discriminant is a pointer value -- relies on ptr-to-int casts in
+// the niche handling code.
+//@compile-flags: -Zmiri-disable-stacked-borrows -Zmiri-disable-validation
+
+fn main() {
+    let x = 42;
+    let val: Option<&i32> = unsafe { std::mem::transmute((&x as *const i32).wrapping_offset(2)) };
+    assert!(val.is_some());
+}
diff --git a/src/tools/miri/tests/pass/enums.rs b/src/tools/miri/tests/pass/enums.rs
new file mode 100644
index 000000000000..ac7aafc1bb2e
--- /dev/null
+++ b/src/tools/miri/tests/pass/enums.rs
@@ -0,0 +1,143 @@
+enum MyEnum {
+    MyEmptyVariant,
+    MyNewtypeVariant(i32),
+    MyTupleVariant(i32, i32),
+    MyStructVariant { my_first_field: i32, my_second_field: i32 },
+}
+
+fn test(me: MyEnum) {
+    match me {
+        MyEnum::MyEmptyVariant => {}
+        MyEnum::MyNewtypeVariant(ref val) => assert_eq!(val, &42),
+        MyEnum::MyTupleVariant(ref a, ref b) => {
+            assert_eq!(a, &43);
+            assert_eq!(b, &44);
+        }
+        MyEnum::MyStructVariant { ref my_first_field, ref my_second_field } => {
+            assert_eq!(my_first_field, &45);
+            assert_eq!(my_second_field, &46);
+        }
+    }
+}
+
+fn discriminant_overflow() {
+    // Tests for https://github.com/rust-lang/rust/issues/62138.
+    #[repr(u8)]
+    #[allow(dead_code)]
+    enum WithWraparoundInvalidValues {
+        X = 1,
+        Y = 254,
+    }
+
+    #[allow(dead_code)]
+    enum Foo {
+        A,
+        B,
+        C(WithWraparoundInvalidValues),
+    }
+
+    let x = Foo::B;
+    match x {
+        Foo::B => {}
+        _ => panic!(),
+    }
+}
+
+fn more_discriminant_overflow() {
+    pub enum Infallible {}
+
+    // The check that the `bool` field of `V1` is encoding a "niche variant"
+    // (i.e. not `V1`, so `V3` or `V4`) used to be mathematically incorrect,
+    // causing valid `V1` values to be interpreted as other variants.
+    #[allow(dead_code)]
+    pub enum E1 {
+        V1 { f: bool },
+        V2 { f: Infallible },
+        V3,
+        V4,
+    }
+
+    // Computing the discriminant used to be done using the niche type (here `u8`,
+    // from the `bool` field of `V1`), overflowing for variants with large enough
+    // indices (`V3` and `V4`), causing them to be interpreted as other variants.
+    #[allow(dead_code)]
+    #[rustfmt::skip] // rustfmt prefers every variant on its own line
+    pub enum E2<X> {
+        V1 { f: bool },
+
+        /*_00*/ _01(X), _02(X), _03(X), _04(X), _05(X), _06(X), _07(X),
+        _08(X), _09(X), _0A(X), _0B(X), _0C(X), _0D(X), _0E(X), _0F(X),
+        _10(X), _11(X), _12(X), _13(X), _14(X), _15(X), _16(X), _17(X),
+        _18(X), _19(X), _1A(X), _1B(X), _1C(X), _1D(X), _1E(X), _1F(X),
+        _20(X), _21(X), _22(X), _23(X), _24(X), _25(X), _26(X), _27(X),
+        _28(X), _29(X), _2A(X), _2B(X), _2C(X), _2D(X), _2E(X), _2F(X),
+        _30(X), _31(X), _32(X), _33(X), _34(X), _35(X), _36(X), _37(X),
+        _38(X), _39(X), _3A(X), _3B(X), _3C(X), _3D(X), _3E(X), _3F(X),
+        _40(X), _41(X), _42(X), _43(X), _44(X), _45(X), _46(X), _47(X),
+        _48(X), _49(X), _4A(X), _4B(X), _4C(X), _4D(X), _4E(X), _4F(X),
+        _50(X), _51(X), _52(X), _53(X), _54(X), _55(X), _56(X), _57(X),
+        _58(X), _59(X), _5A(X), _5B(X), _5C(X), _5D(X), _5E(X), _5F(X),
+        _60(X), _61(X), _62(X), _63(X), _64(X), _65(X), _66(X), _67(X),
+        _68(X), _69(X), _6A(X), _6B(X), _6C(X), _6D(X), _6E(X), _6F(X),
+        _70(X), _71(X), _72(X), _73(X), _74(X), _75(X), _76(X), _77(X),
+        _78(X), _79(X), _7A(X), _7B(X), _7C(X), _7D(X), _7E(X), _7F(X),
+        _80(X), _81(X), _82(X), _83(X), _84(X), _85(X), _86(X), _87(X),
+        _88(X), _89(X), _8A(X), _8B(X), _8C(X), _8D(X), _8E(X), _8F(X),
+        _90(X), _91(X), _92(X), _93(X), _94(X), _95(X), _96(X), _97(X),
+        _98(X), _99(X), _9A(X), _9B(X), _9C(X), _9D(X), _9E(X), _9F(X),
+        _A0(X), _A1(X), _A2(X), _A3(X), _A4(X), _A5(X), _A6(X), _A7(X),
+        _A8(X), _A9(X), _AA(X), _AB(X), _AC(X), _AD(X), _AE(X), _AF(X),
+        _B0(X), _B1(X), _B2(X), _B3(X), _B4(X), _B5(X), _B6(X), _B7(X),
+        _B8(X), _B9(X), _BA(X), _BB(X), _BC(X), _BD(X), _BE(X), _BF(X),
+        _C0(X), _C1(X), _C2(X), _C3(X), _C4(X), _C5(X), _C6(X), _C7(X),
+        _C8(X), _C9(X), _CA(X), _CB(X), _CC(X), _CD(X), _CE(X), _CF(X),
+        _D0(X), _D1(X), _D2(X), _D3(X), _D4(X), _D5(X), _D6(X), _D7(X),
+        _D8(X), _D9(X), _DA(X), _DB(X), _DC(X), _DD(X), _DE(X), _DF(X),
+        _E0(X), _E1(X), _E2(X), _E3(X), _E4(X), _E5(X), _E6(X), _E7(X),
+        _E8(X), _E9(X), _EA(X), _EB(X), _EC(X), _ED(X), _EE(X), _EF(X),
+        _F0(X), _F1(X), _F2(X), _F3(X), _F4(X), _F5(X), _F6(X), _F7(X),
+        _F8(X), _F9(X), _FA(X), _FB(X), _FC(X), _FD(X), _FE(X), _FF(X),
+
+        V3,
+        V4,
+    }
+
+    if let E1::V2 { .. } = (E1::V1 { f: true }) {
+        unreachable!()
+    }
+    if let E1::V1 { .. } = (E1::V1 { f: true }) {
+    } else {
+        unreachable!()
+    }
+
+    if let E2::V1 { .. } = E2::V3::<Infallible> {
+        unreachable!()
+    }
+    if let E2::V3 { .. } = E2::V3::<Infallible> {
+    } else {
+        unreachable!()
+    }
+}
+
+fn overaligned_casts() {
+    #[allow(dead_code)]
+    #[repr(align(8))]
+    enum Aligned {
+        Zero = 0,
+        One = 1,
+    }
+
+    let aligned = Aligned::Zero;
+    assert_eq!(aligned as u8, 0);
+}
+
+fn main() {
+    test(MyEnum::MyEmptyVariant);
+    test(MyEnum::MyNewtypeVariant(42));
+    test(MyEnum::MyTupleVariant(43, 44));
+    test(MyEnum::MyStructVariant { my_first_field: 45, my_second_field: 46 });
+
+    discriminant_overflow();
+    more_discriminant_overflow();
+    overaligned_casts();
+}
diff --git a/src/tools/miri/tests/pass/extern_crate_std_in_main.rs b/src/tools/miri/tests/pass/extern_crate_std_in_main.rs
new file mode 100644
index 000000000000..8f71e613375e
--- /dev/null
+++ b/src/tools/miri/tests/pass/extern_crate_std_in_main.rs
@@ -0,0 +1,5 @@
+#![no_std]
+
+fn main() {
+    extern crate std;
+}
diff --git a/src/tools/miri/tests/pass/extern_types.rs b/src/tools/miri/tests/pass/extern_types.rs
new file mode 100644
index 000000000000..aa4c65ea8928
--- /dev/null
+++ b/src/tools/miri/tests/pass/extern_types.rs
@@ -0,0 +1,10 @@
+#![feature(extern_types)]
+
+extern "C" {
+    type Foo;
+}
+
+fn main() {
+    let x: &Foo = unsafe { &*(16 as *const Foo) };
+    let _y: &Foo = &*x;
+}
diff --git a/src/tools/miri/tests/pass/extern_types.stderr b/src/tools/miri/tests/pass/extern_types.stderr
new file mode 100644
index 000000000000..2e18f6930589
--- /dev/null
+++ b/src/tools/miri/tests/pass/extern_types.stderr
@@ -0,0 +1,15 @@
+warning: integer-to-pointer cast
+  --> $DIR/extern_types.rs:LL:CC
+   |
+LL |     let x: &Foo = unsafe { &*(16 as *const Foo) };
+   |                              ^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
+   |
+   = help: This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,
+   = help: which means that Miri might miss pointer bugs in this program.
+   = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation.
+   = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
+   = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics.
+   = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/extern_types.rs:LL:CC
+
diff --git a/src/tools/miri/tests/pass/fat_ptr.rs b/src/tools/miri/tests/pass/fat_ptr.rs
new file mode 100644
index 000000000000..8317156a218d
--- /dev/null
+++ b/src/tools/miri/tests/pass/fat_ptr.rs
@@ -0,0 +1,51 @@
+// test that ordinary fat pointer operations work.
+
+struct Wrapper<T: ?Sized>(u32, T);
+
+struct FatPtrContainer<'a> {
+    ptr: &'a [u8],
+}
+
+fn fat_ptr_project(a: &Wrapper<[u8]>) -> &[u8] {
+    &a.1
+}
+
+fn fat_ptr_simple(a: &[u8]) -> &[u8] {
+    a
+}
+
+fn fat_ptr_via_local(a: &[u8]) -> &[u8] {
+    let x = a;
+    x
+}
+
+fn fat_ptr_from_struct(s: FatPtrContainer) -> &[u8] {
+    s.ptr
+}
+
+fn fat_ptr_to_struct(a: &[u8]) -> FatPtrContainer {
+    FatPtrContainer { ptr: a }
+}
+
+fn fat_ptr_store_to<'a>(a: &'a [u8], b: &mut &'a [u8]) {
+    *b = a;
+}
+
+fn fat_ptr_constant() -> &'static str {
+    "HELLO"
+}
+
+fn main() {
+    let a = Wrapper(4, [7, 6, 5]);
+
+    let p = fat_ptr_project(&a);
+    let p = fat_ptr_simple(p);
+    let p = fat_ptr_via_local(p);
+    let p = fat_ptr_from_struct(fat_ptr_to_struct(p));
+
+    let mut target: &[u8] = &[42];
+    fat_ptr_store_to(p, &mut target);
+    assert_eq!(target, &a.1);
+
+    assert_eq!(fat_ptr_constant(), "HELLO");
+}
diff --git a/src/tools/miri/tests/pass/float.rs b/src/tools/miri/tests/pass/float.rs
new file mode 100644
index 000000000000..48dd99441ebf
--- /dev/null
+++ b/src/tools/miri/tests/pass/float.rs
@@ -0,0 +1,555 @@
+#![feature(stmt_expr_attributes, bench_black_box)]
+#![allow(arithmetic_overflow)]
+use std::fmt::Debug;
+use std::hint::black_box;
+
+fn main() {
+    basic();
+    casts();
+    more_casts();
+    ops();
+    nan_casts();
+}
+
+// Helper function to avoid promotion so that this tests "run-time" casts, not CTFE.
+// Doesn't make a big difference when running this in Miri, but it means we can compare this
+// with the LLVM backend by running `rustc -Zmir-opt-level=0 -Zsaturating-float-casts`.
+#[track_caller]
+#[inline(never)]
+fn assert_eq<T: PartialEq + Debug>(x: T, y: T) {
+    assert_eq!(x, y);
+}
+
+trait FloatToInt<Int>: Copy {
+    fn cast(self) -> Int;
+    unsafe fn cast_unchecked(self) -> Int;
+}
+
+impl FloatToInt<i8> for f32 {
+    fn cast(self) -> i8 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i8 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<i32> for f32 {
+    fn cast(self) -> i32 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i32 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<u32> for f32 {
+    fn cast(self) -> u32 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> u32 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<i64> for f32 {
+    fn cast(self) -> i64 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i64 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<u64> for f32 {
+    fn cast(self) -> u64 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> u64 {
+        self.to_int_unchecked()
+    }
+}
+
+impl FloatToInt<i8> for f64 {
+    fn cast(self) -> i8 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i8 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<i32> for f64 {
+    fn cast(self) -> i32 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i32 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<u32> for f64 {
+    fn cast(self) -> u32 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> u32 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<i64> for f64 {
+    fn cast(self) -> i64 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i64 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<u64> for f64 {
+    fn cast(self) -> u64 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> u64 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<i128> for f64 {
+    fn cast(self) -> i128 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> i128 {
+        self.to_int_unchecked()
+    }
+}
+impl FloatToInt<u128> for f64 {
+    fn cast(self) -> u128 {
+        self as _
+    }
+    unsafe fn cast_unchecked(self) -> u128 {
+        self.to_int_unchecked()
+    }
+}
+
+/// Test this cast both via `as` and via `approx_unchecked` (i.e., it must not saturate).
+#[track_caller]
+#[inline(never)]
+fn test_both_cast<F, I>(x: F, y: I)
+where
+    F: FloatToInt<I>,
+    I: PartialEq + Debug,
+{
+    assert_eq!(x.cast(), y);
+    assert_eq!(unsafe { x.cast_unchecked() }, y);
+}
+
+fn basic() {
+    // basic arithmetic
+    assert_eq(6.0_f32 * 6.0_f32, 36.0_f32);
+    assert_eq(6.0_f64 * 6.0_f64, 36.0_f64);
+    assert_eq(-{ 5.0_f32 }, -5.0_f32);
+    assert_eq(-{ 5.0_f64 }, -5.0_f64);
+    // infinities, NaN
+    assert!((5.0_f32 / 0.0).is_infinite());
+    assert_ne!({ 5.0_f32 / 0.0 }, { -5.0_f32 / 0.0 });
+    assert!((5.0_f64 / 0.0).is_infinite());
+    assert_ne!({ 5.0_f64 / 0.0 }, { 5.0_f64 / -0.0 });
+    assert!((-5.0_f32).sqrt().is_nan());
+    assert!((-5.0_f64).sqrt().is_nan());
+    assert_ne!(f32::NAN, f32::NAN);
+    assert_ne!(f64::NAN, f64::NAN);
+    // negative zero
+    let posz = 0.0f32;
+    let negz = -0.0f32;
+    assert_eq(posz, negz);
+    assert_ne!(posz.to_bits(), negz.to_bits());
+    let posz = 0.0f64;
+    let negz = -0.0f64;
+    assert_eq(posz, negz);
+    assert_ne!(posz.to_bits(), negz.to_bits());
+    // byte-level transmute
+    let x: u64 = unsafe { std::mem::transmute(42.0_f64) };
+    let y: f64 = unsafe { std::mem::transmute(x) };
+    assert_eq(y, 42.0_f64);
+    let x: u32 = unsafe { std::mem::transmute(42.0_f32) };
+    let y: f32 = unsafe { std::mem::transmute(x) };
+    assert_eq(y, 42.0_f32);
+}
+
+/// Many of these test values are taken from
+/// https://github.com/WebAssembly/testsuite/blob/master/conversions.wast.
+fn casts() {
+    // f32 -> i8
+    test_both_cast::<f32, i8>(127.99, 127);
+    test_both_cast::<f32, i8>(-128.99, -128);
+
+    // f32 -> i32
+    test_both_cast::<f32, i32>(0.0, 0);
+    test_both_cast::<f32, i32>(-0.0, 0);
+    test_both_cast::<f32, i32>(/*0x1p-149*/ f32::from_bits(0x00000001), 0);
+    test_both_cast::<f32, i32>(/*-0x1p-149*/ f32::from_bits(0x80000001), 0);
+    test_both_cast::<f32, i32>(/*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd), 1);
+    test_both_cast::<f32, i32>(/*-0x1.19999ap+0*/ f32::from_bits(0xbf8ccccd), -1);
+    test_both_cast::<f32, i32>(1.9, 1);
+    test_both_cast::<f32, i32>(-1.9, -1);
+    test_both_cast::<f32, i32>(5.0, 5);
+    test_both_cast::<f32, i32>(-5.0, -5);
+    test_both_cast::<f32, i32>(2147483520.0, 2147483520);
+    test_both_cast::<f32, i32>(-2147483648.0, -2147483648);
+    // unrepresentable casts
+    assert_eq::<i32>(2147483648.0f32 as i32, i32::MAX);
+    assert_eq::<i32>(-2147483904.0f32 as i32, i32::MIN);
+    assert_eq::<i32>(f32::MAX as i32, i32::MAX);
+    assert_eq::<i32>(f32::MIN as i32, i32::MIN);
+    assert_eq::<i32>(f32::INFINITY as i32, i32::MAX);
+    assert_eq::<i32>(f32::NEG_INFINITY as i32, i32::MIN);
+    assert_eq::<i32>(f32::NAN as i32, 0);
+    assert_eq::<i32>((-f32::NAN) as i32, 0);
+
+    // f32 -> u32
+    test_both_cast::<f32, u32>(0.0, 0);
+    test_both_cast::<f32, u32>(-0.0, 0);
+    test_both_cast::<f32, u32>(-0.9999999, 0);
+    test_both_cast::<f32, u32>(/*0x1p-149*/ f32::from_bits(0x1), 0);
+    test_both_cast::<f32, u32>(/*-0x1p-149*/ f32::from_bits(0x80000001), 0);
+    test_both_cast::<f32, u32>(/*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd), 1);
+    test_both_cast::<f32, u32>(1.9, 1);
+    test_both_cast::<f32, u32>(5.0, 5);
+    test_both_cast::<f32, u32>(2147483648.0, 0x8000_0000);
+    test_both_cast::<f32, u32>(4294967040.0, 0u32.wrapping_sub(256));
+    test_both_cast::<f32, u32>(/*-0x1.ccccccp-1*/ f32::from_bits(0xbf666666), 0);
+    test_both_cast::<f32, u32>(/*-0x1.fffffep-1*/ f32::from_bits(0xbf7fffff), 0);
+    test_both_cast::<f32, u32>((u32::MAX - 128) as f32, u32::MAX - 255); // rounding loss
+    // unrepresentable casts
+    assert_eq::<u32>((u32::MAX - 127) as f32 as u32, u32::MAX); // rounds up and then becomes unrepresentable
+    assert_eq::<u32>(4294967296.0f32 as u32, u32::MAX);
+    assert_eq::<u32>(-5.0f32 as u32, 0);
+    assert_eq::<u32>(f32::MAX as u32, u32::MAX);
+    assert_eq::<u32>(f32::MIN as u32, 0);
+    assert_eq::<u32>(f32::INFINITY as u32, u32::MAX);
+    assert_eq::<u32>(f32::NEG_INFINITY as u32, 0);
+    assert_eq::<u32>(f32::NAN as u32, 0);
+    assert_eq::<u32>((-f32::NAN) as u32, 0);
+
+    // f32 -> i64
+    test_both_cast::<f32, i64>(4294967296.0, 4294967296);
+    test_both_cast::<f32, i64>(-4294967296.0, -4294967296);
+    test_both_cast::<f32, i64>(9223371487098961920.0, 9223371487098961920);
+    test_both_cast::<f32, i64>(-9223372036854775808.0, -9223372036854775808);
+
+    // f64 -> i8
+    test_both_cast::<f64, i8>(127.99, 127);
+    test_both_cast::<f64, i8>(-128.99, -128);
+
+    // f64 -> i32
+    test_both_cast::<f64, i32>(0.0, 0);
+    test_both_cast::<f64, i32>(-0.0, 0);
+    test_both_cast::<f64, i32>(/*0x1.199999999999ap+0*/ f64::from_bits(0x3ff199999999999a), 1);
+    test_both_cast::<f64, i32>(
+        /*-0x1.199999999999ap+0*/ f64::from_bits(0xbff199999999999a),
+        -1,
+    );
+    test_both_cast::<f64, i32>(1.9, 1);
+    test_both_cast::<f64, i32>(-1.9, -1);
+    test_both_cast::<f64, i32>(1e8, 100_000_000);
+    test_both_cast::<f64, i32>(2147483647.0, 2147483647);
+    test_both_cast::<f64, i32>(-2147483648.0, -2147483648);
+    // unrepresentable casts
+    assert_eq::<i32>(2147483648.0f64 as i32, i32::MAX);
+    assert_eq::<i32>(-2147483649.0f64 as i32, i32::MIN);
+
+    // f64 -> i64
+    test_both_cast::<f64, i64>(0.0, 0);
+    test_both_cast::<f64, i64>(-0.0, 0);
+    test_both_cast::<f64, i64>(/*0x0.0000000000001p-1022*/ f64::from_bits(0x1), 0);
+    test_both_cast::<f64, i64>(
+        /*-0x0.0000000000001p-1022*/ f64::from_bits(0x8000000000000001),
+        0,
+    );
+    test_both_cast::<f64, i64>(/*0x1.199999999999ap+0*/ f64::from_bits(0x3ff199999999999a), 1);
+    test_both_cast::<f64, i64>(
+        /*-0x1.199999999999ap+0*/ f64::from_bits(0xbff199999999999a),
+        -1,
+    );
+    test_both_cast::<f64, i64>(5.0, 5);
+    test_both_cast::<f64, i64>(5.9, 5);
+    test_both_cast::<f64, i64>(-5.0, -5);
+    test_both_cast::<f64, i64>(-5.9, -5);
+    test_both_cast::<f64, i64>(4294967296.0, 4294967296);
+    test_both_cast::<f64, i64>(-4294967296.0, -4294967296);
+    test_both_cast::<f64, i64>(9223372036854774784.0, 9223372036854774784);
+    test_both_cast::<f64, i64>(-9223372036854775808.0, -9223372036854775808);
+    // unrepresentable casts
+    assert_eq::<i64>(9223372036854775808.0f64 as i64, i64::MAX);
+    assert_eq::<i64>(-9223372036854777856.0f64 as i64, i64::MIN);
+    assert_eq::<i64>(f64::MAX as i64, i64::MAX);
+    assert_eq::<i64>(f64::MIN as i64, i64::MIN);
+    assert_eq::<i64>(f64::INFINITY as i64, i64::MAX);
+    assert_eq::<i64>(f64::NEG_INFINITY as i64, i64::MIN);
+    assert_eq::<i64>(f64::NAN as i64, 0);
+    assert_eq::<i64>((-f64::NAN) as i64, 0);
+
+    // f64 -> u64
+    test_both_cast::<f64, u64>(0.0, 0);
+    test_both_cast::<f64, u64>(-0.0, 0);
+    test_both_cast::<f64, u64>(-0.99999999999, 0);
+    test_both_cast::<f64, u64>(5.0, 5);
+    test_both_cast::<f64, u64>(1e16, 10000000000000000);
+    test_both_cast::<f64, u64>((u64::MAX - 1024) as f64, u64::MAX - 2047); // rounding loss
+    test_both_cast::<f64, u64>(9223372036854775808.0, 9223372036854775808);
+    // unrepresentable casts
+    assert_eq::<u64>(-5.0f64 as u64, 0);
+    assert_eq::<u64>((u64::MAX - 1023) as f64 as u64, u64::MAX); // rounds up and then becomes unrepresentable
+    assert_eq::<u64>(18446744073709551616.0f64 as u64, u64::MAX);
+    assert_eq::<u64>(f64::MAX as u64, u64::MAX);
+    assert_eq::<u64>(f64::MIN as u64, 0);
+    assert_eq::<u64>(f64::INFINITY as u64, u64::MAX);
+    assert_eq::<u64>(f64::NEG_INFINITY as u64, 0);
+    assert_eq::<u64>(f64::NAN as u64, 0);
+    assert_eq::<u64>((-f64::NAN) as u64, 0);
+
+    // f64 -> i128
+    assert_eq::<i128>(f64::MAX as i128, i128::MAX);
+    assert_eq::<i128>(f64::MIN as i128, i128::MIN);
+
+    // f64 -> u128
+    assert_eq::<u128>(f64::MAX as u128, u128::MAX);
+    assert_eq::<u128>(f64::MIN as u128, 0);
+
+    // int -> f32
+    assert_eq::<f32>(127i8 as f32, 127.0);
+    assert_eq::<f32>(2147483647i32 as f32, 2147483648.0);
+    assert_eq::<f32>((-2147483648i32) as f32, -2147483648.0);
+    assert_eq::<f32>(1234567890i32 as f32, /*0x1.26580cp+30*/ f32::from_bits(0x4e932c06));
+    assert_eq::<f32>(16777217i32 as f32, 16777216.0);
+    assert_eq::<f32>((-16777217i32) as f32, -16777216.0);
+    assert_eq::<f32>(16777219i32 as f32, 16777220.0);
+    assert_eq::<f32>((-16777219i32) as f32, -16777220.0);
+    assert_eq::<f32>(
+        0x7fffff4000000001i64 as f32,
+        /*0x1.fffffep+62*/ f32::from_bits(0x5effffff),
+    );
+    assert_eq::<f32>(
+        0x8000004000000001u64 as i64 as f32,
+        /*-0x1.fffffep+62*/ f32::from_bits(0xdeffffff),
+    );
+    assert_eq::<f32>(
+        0x0020000020000001i64 as f32,
+        /*0x1.000002p+53*/ f32::from_bits(0x5a000001),
+    );
+    assert_eq::<f32>(
+        0xffdfffffdfffffffu64 as i64 as f32,
+        /*-0x1.000002p+53*/ f32::from_bits(0xda000001),
+    );
+    assert_eq::<f32>(i128::MIN as f32, -170141183460469231731687303715884105728.0f32);
+    assert_eq::<f32>(u128::MAX as f32, f32::INFINITY); // saturation
+
+    // int -> f64
+    assert_eq::<f64>(127i8 as f64, 127.0);
+    assert_eq::<f64>(i16::MIN as f64, -32768.0f64);
+    assert_eq::<f64>(2147483647i32 as f64, 2147483647.0);
+    assert_eq::<f64>(-2147483648i32 as f64, -2147483648.0);
+    assert_eq::<f64>(987654321i32 as f64, 987654321.0);
+    assert_eq::<f64>(9223372036854775807i64 as f64, 9223372036854775807.0);
+    assert_eq::<f64>(-9223372036854775808i64 as f64, -9223372036854775808.0);
+    assert_eq::<f64>(4669201609102990i64 as f64, 4669201609102990.0); // Feigenbaum (?)
+    assert_eq::<f64>(9007199254740993i64 as f64, 9007199254740992.0);
+    assert_eq::<f64>(-9007199254740993i64 as f64, -9007199254740992.0);
+    assert_eq::<f64>(9007199254740995i64 as f64, 9007199254740996.0);
+    assert_eq::<f64>(-9007199254740995i64 as f64, -9007199254740996.0);
+    assert_eq::<f64>(u128::MAX as f64, 340282366920938463463374607431768211455.0f64); // even that fits...
+
+    // f32 -> f64
+    assert_eq::<u64>((0.0f32 as f64).to_bits(), 0.0f64.to_bits());
+    assert_eq::<u64>(((-0.0f32) as f64).to_bits(), (-0.0f64).to_bits());
+    assert_eq::<f64>(5.0f32 as f64, 5.0f64);
+    assert_eq::<f64>(
+        /*0x1p-149*/ f32::from_bits(0x1) as f64,
+        /*0x1p-149*/ f64::from_bits(0x36a0000000000000),
+    );
+    assert_eq::<f64>(
+        /*-0x1p-149*/ f32::from_bits(0x80000001) as f64,
+        /*-0x1p-149*/ f64::from_bits(0xb6a0000000000000),
+    );
+    assert_eq::<f64>(
+        /*0x1.fffffep+127*/ f32::from_bits(0x7f7fffff) as f64,
+        /*0x1.fffffep+127*/ f64::from_bits(0x47efffffe0000000),
+    );
+    assert_eq::<f64>(
+        /*-0x1.fffffep+127*/ (-f32::from_bits(0x7f7fffff)) as f64,
+        /*-0x1.fffffep+127*/ -f64::from_bits(0x47efffffe0000000),
+    );
+    assert_eq::<f64>(
+        /*0x1p-119*/ f32::from_bits(0x4000000) as f64,
+        /*0x1p-119*/ f64::from_bits(0x3880000000000000),
+    );
+    assert_eq::<f64>(
+        /*0x1.8f867ep+125*/ f32::from_bits(0x7e47c33f) as f64,
+        6.6382536710104395e+37,
+    );
+    assert_eq::<f64>(f32::INFINITY as f64, f64::INFINITY);
+    assert_eq::<f64>(f32::NEG_INFINITY as f64, f64::NEG_INFINITY);
+
+    // f64 -> f32
+    assert_eq::<u32>((0.0f64 as f32).to_bits(), 0.0f32.to_bits());
+    assert_eq::<u32>(((-0.0f64) as f32).to_bits(), (-0.0f32).to_bits());
+    assert_eq::<f32>(5.0f64 as f32, 5.0f32);
+    assert_eq::<f32>(/*0x0.0000000000001p-1022*/ f64::from_bits(0x1) as f32, 0.0);
+    assert_eq::<f32>(/*-0x0.0000000000001p-1022*/ (-f64::from_bits(0x1)) as f32, -0.0);
+    assert_eq::<f32>(
+        /*0x1.fffffe0000000p-127*/ f64::from_bits(0x380fffffe0000000) as f32,
+        /*0x1p-149*/ f32::from_bits(0x800000),
+    );
+    assert_eq::<f32>(
+        /*0x1.4eae4f7024c7p+108*/ f64::from_bits(0x46b4eae4f7024c70) as f32,
+        /*0x1.4eae5p+108*/ f32::from_bits(0x75a75728),
+    );
+    assert_eq::<f32>(f64::MAX as f32, f32::INFINITY);
+    assert_eq::<f32>(f64::MIN as f32, f32::NEG_INFINITY);
+    assert_eq::<f32>(f64::INFINITY as f32, f32::INFINITY);
+    assert_eq::<f32>(f64::NEG_INFINITY as f32, f32::NEG_INFINITY);
+}
+
+fn ops() {
+    // f32 min/max
+    assert_eq((1.0 as f32).max(-1.0), 1.0);
+    assert_eq((1.0 as f32).min(-1.0), -1.0);
+    assert_eq(f32::NAN.min(9.0), 9.0);
+    assert_eq(f32::NAN.max(-9.0), -9.0);
+    assert_eq((9.0 as f32).min(f32::NAN), 9.0);
+    assert_eq((-9.0 as f32).max(f32::NAN), -9.0);
+
+    // f64 min/max
+    assert_eq((1.0 as f64).max(-1.0), 1.0);
+    assert_eq((1.0 as f64).min(-1.0), -1.0);
+    assert_eq(f64::NAN.min(9.0), 9.0);
+    assert_eq(f64::NAN.max(-9.0), -9.0);
+    assert_eq((9.0 as f64).min(f64::NAN), 9.0);
+    assert_eq((-9.0 as f64).max(f64::NAN), -9.0);
+
+    // f32 copysign
+    assert_eq(3.5_f32.copysign(0.42), 3.5_f32);
+    assert_eq(3.5_f32.copysign(-0.42), -3.5_f32);
+    assert_eq((-3.5_f32).copysign(0.42), 3.5_f32);
+    assert_eq((-3.5_f32).copysign(-0.42), -3.5_f32);
+    assert!(f32::NAN.copysign(1.0).is_nan());
+
+    // f64 copysign
+    assert_eq(3.5_f64.copysign(0.42), 3.5_f64);
+    assert_eq(3.5_f64.copysign(-0.42), -3.5_f64);
+    assert_eq((-3.5_f64).copysign(0.42), 3.5_f64);
+    assert_eq((-3.5_f64).copysign(-0.42), -3.5_f64);
+    assert!(f64::NAN.copysign(1.0).is_nan());
+}
+
+/// Tests taken from rustc test suite.
+///
+
+macro_rules! test {
+    ($val:expr, $src_ty:ident -> $dest_ty:ident, $expected:expr) => (
+        // black_box disables constant evaluation to test run-time conversions:
+        assert_eq!(black_box::<$src_ty>($val) as $dest_ty, $expected,
+                    "run-time {} -> {}", stringify!($src_ty), stringify!($dest_ty));
+
+        {
+            const X: $src_ty = $val;
+            const Y: $dest_ty = X as $dest_ty;
+            assert_eq!(Y, $expected,
+                        "const eval {} -> {}", stringify!($src_ty), stringify!($dest_ty));
+        }
+    );
+
+    ($fval:expr, f* -> $ity:ident, $ival:expr) => (
+        test!($fval, f32 -> $ity, $ival);
+        test!($fval, f64 -> $ity, $ival);
+    )
+}
+
+macro_rules! common_fptoi_tests {
+    ($fty:ident -> $($ity:ident)+) => ({ $(
+        test!($fty::NAN, $fty -> $ity, 0);
+        test!($fty::INFINITY, $fty -> $ity, $ity::MAX);
+        test!($fty::NEG_INFINITY, $fty -> $ity, $ity::MIN);
+        // These two tests are not solely float->int tests, in particular the latter relies on
+        // `u128::MAX as f32` not being UB. But that's okay, since this file tests int->float
+        // as well, the test is just slightly misplaced.
+        test!($ity::MIN as $fty, $fty -> $ity, $ity::MIN);
+        test!($ity::MAX as $fty, $fty -> $ity, $ity::MAX);
+        test!(0., $fty -> $ity, 0);
+        test!($fty::MIN_POSITIVE, $fty -> $ity, 0);
+        test!(-0.9, $fty -> $ity, 0);
+        test!(1., $fty -> $ity, 1);
+        test!(42., $fty -> $ity, 42);
+    )+ });
+
+    (f* -> $($ity:ident)+) => ({
+        common_fptoi_tests!(f32 -> $($ity)+);
+        common_fptoi_tests!(f64 -> $($ity)+);
+    })
+}
+
+macro_rules! fptoui_tests {
+    ($fty: ident -> $($ity: ident)+) => ({ $(
+        test!(-0., $fty -> $ity, 0);
+        test!(-$fty::MIN_POSITIVE, $fty -> $ity, 0);
+        test!(-0.99999994, $fty -> $ity, 0);
+        test!(-1., $fty -> $ity, 0);
+        test!(-100., $fty -> $ity, 0);
+        test!(#[allow(overflowing_literals)] -1e50, $fty -> $ity, 0);
+        test!(#[allow(overflowing_literals)] -1e130, $fty -> $ity, 0);
+    )+ });
+
+    (f* -> $($ity:ident)+) => ({
+        fptoui_tests!(f32 -> $($ity)+);
+        fptoui_tests!(f64 -> $($ity)+);
+    })
+}
+
+fn more_casts() {
+    common_fptoi_tests!(f* -> i8 i16 i32 i64 u8 u16 u32 u64);
+    fptoui_tests!(f* -> u8 u16 u32 u64);
+    common_fptoi_tests!(f* -> i128 u128);
+    fptoui_tests!(f* -> u128);
+
+    // The following tests cover edge cases for some integer types.
+
+    // # u8
+    test!(254., f* -> u8, 254);
+    test!(256., f* -> u8, 255);
+
+    // # i8
+    test!(-127., f* -> i8, -127);
+    test!(-129., f* -> i8, -128);
+    test!(126., f* -> i8, 126);
+    test!(128., f* -> i8, 127);
+
+    // # i32
+    // -2147483648. is i32::MIN (exactly)
+    test!(-2147483648., f* -> i32, i32::MIN);
+    // 2147483648. is i32::MAX rounded up
+    test!(2147483648., f32 -> i32, 2147483647);
+    // With 24 significand bits, floats with magnitude in [2^30 + 1, 2^31] are rounded to
+    // multiples of 2^7. Therefore, nextDown(round(i32::MAX)) is 2^31 - 128:
+    test!(2147483520., f32 -> i32, 2147483520);
+    // Similarly, nextUp(i32::MIN) is i32::MIN + 2^8 and nextDown(i32::MIN) is i32::MIN - 2^7
+    test!(-2147483904., f* -> i32, i32::MIN);
+    test!(-2147483520., f* -> i32, -2147483520);
+
+    // # u32
+    // round(MAX) and nextUp(round(MAX))
+    test!(4294967040., f* -> u32, 4294967040);
+    test!(4294967296., f* -> u32, 4294967295);
+
+    // # u128
+    // float->int:
+    test!(f32::MAX, f32 -> u128, 0xffffff00000000000000000000000000);
+    // nextDown(f32::MAX) = 2^128 - 2 * 2^104
+    const SECOND_LARGEST_F32: f32 = 340282326356119256160033759537265639424.;
+    test!(SECOND_LARGEST_F32, f32 -> u128, 0xfffffe00000000000000000000000000);
+}
+
+fn nan_casts() {
+    let nan1 = f64::from_bits(0x7FF0_0001_0000_0001u64);
+    let nan2 = f64::from_bits(0x7FF0_0000_0000_0001u64);
+
+    assert!(nan1.is_nan());
+    assert!(nan2.is_nan());
+
+    let nan1_32 = nan1 as f32;
+    let nan2_32 = nan2 as f32;
+
+    assert!(nan1_32.is_nan());
+    assert!(nan2_32.is_nan());
+}
diff --git a/src/tools/miri/tests/pass/float_fast_math.rs b/src/tools/miri/tests/pass/float_fast_math.rs
new file mode 100644
index 000000000000..52d985667df2
--- /dev/null
+++ b/src/tools/miri/tests/pass/float_fast_math.rs
@@ -0,0 +1,34 @@
+#![feature(core_intrinsics)]
+
+use std::intrinsics::{fadd_fast, fdiv_fast, fmul_fast, frem_fast, fsub_fast};
+
+#[inline(never)]
+pub fn test_operations_f64(a: f64, b: f64) {
+    // make sure they all map to the correct operation
+    unsafe {
+        assert_eq!(fadd_fast(a, b), a + b);
+        assert_eq!(fsub_fast(a, b), a - b);
+        assert_eq!(fmul_fast(a, b), a * b);
+        assert_eq!(fdiv_fast(a, b), a / b);
+        assert_eq!(frem_fast(a, b), a % b);
+    }
+}
+
+#[inline(never)]
+pub fn test_operations_f32(a: f32, b: f32) {
+    // make sure they all map to the correct operation
+    unsafe {
+        assert_eq!(fadd_fast(a, b), a + b);
+        assert_eq!(fsub_fast(a, b), a - b);
+        assert_eq!(fmul_fast(a, b), a * b);
+        assert_eq!(fdiv_fast(a, b), a / b);
+        assert_eq!(frem_fast(a, b), a % b);
+    }
+}
+
+fn main() {
+    test_operations_f64(1., 2.);
+    test_operations_f64(10., 5.);
+    test_operations_f32(11., 2.);
+    test_operations_f32(10., 15.);
+}
diff --git a/src/tools/miri/tests/pass/format.rs b/src/tools/miri/tests/pass/format.rs
new file mode 100644
index 000000000000..053cce36130c
--- /dev/null
+++ b/src/tools/miri/tests/pass/format.rs
@@ -0,0 +1,4 @@
+fn main() {
+    println!("Hello {}", 13);
+    println!("{:0<width$}", "hello", width = 10);
+}
diff --git a/src/tools/miri/tests/pass/format.stdout b/src/tools/miri/tests/pass/format.stdout
new file mode 100644
index 000000000000..3c9a55d0d4c1
--- /dev/null
+++ b/src/tools/miri/tests/pass/format.stdout
@@ -0,0 +1,2 @@
+Hello 13
+hello00000
diff --git a/src/tools/miri/tests/pass/from_utf8.rs b/src/tools/miri/tests/pass/from_utf8.rs
new file mode 100644
index 000000000000..ce59e60a932d
--- /dev/null
+++ b/src/tools/miri/tests/pass/from_utf8.rs
@@ -0,0 +1,3 @@
+fn main() {
+    let _val = ::std::str::from_utf8(b"a");
+}
diff --git a/src/tools/miri/tests/pass/function_calls/disable_abi_check.rs b/src/tools/miri/tests/pass/function_calls/disable_abi_check.rs
new file mode 100644
index 000000000000..e6251b535588
--- /dev/null
+++ b/src/tools/miri/tests/pass/function_calls/disable_abi_check.rs
@@ -0,0 +1,24 @@
+//@compile-flags: -Zmiri-disable-abi-check
+#![feature(core_intrinsics)]
+
+fn main() {
+    fn foo() {}
+
+    extern "C" fn try_fn(ptr: *mut u8) {
+        assert!(ptr.is_null());
+    }
+
+    extern "Rust" {
+        fn malloc(size: usize) -> *mut std::ffi::c_void;
+    }
+
+    unsafe {
+        let _ = malloc(0);
+        std::mem::transmute::<fn(), extern "C" fn()>(foo)();
+        std::intrinsics::r#try(
+            std::mem::transmute::<extern "C" fn(*mut u8), _>(try_fn),
+            std::ptr::null_mut(),
+            |_, _| unreachable!(),
+        );
+    }
+}
diff --git a/src/tools/miri/tests/pass/function_calls/exported_symbol.rs b/src/tools/miri/tests/pass/function_calls/exported_symbol.rs
new file mode 100644
index 000000000000..27aee9c88358
--- /dev/null
+++ b/src/tools/miri/tests/pass/function_calls/exported_symbol.rs
@@ -0,0 +1,79 @@
+#![feature(rustc_attrs)]
+
+#[no_mangle]
+extern "C" fn foo() -> i32 {
+    -1
+}
+
+#[export_name = "bar"]
+fn bar() -> i32 {
+    -2
+}
+
+#[rustc_std_internal_symbol]
+fn baz() -> i32 {
+    -3
+}
+
+struct AssocFn;
+
+impl AssocFn {
+    #[no_mangle]
+    fn qux() -> i32 {
+        -4
+    }
+}
+
+fn main() {
+    // Repeat calls to make sure the `Instance` cache is not broken.
+    for _ in 0..3 {
+        extern "C" {
+            fn foo() -> i32;
+            fn free(_: *mut std::ffi::c_void);
+        }
+
+        assert_eq!(unsafe { foo() }, -1);
+
+        // `free()` is a built-in shim, so calling it will add ("free", None) to the cache.
+        // Test that the cache is not broken with ("free", None).
+        unsafe { free(std::ptr::null_mut()) }
+
+        extern "Rust" {
+            fn bar() -> i32;
+            fn baz() -> i32;
+            fn qux() -> i32;
+        }
+
+        assert_eq!(unsafe { bar() }, -2);
+        assert_eq!(unsafe { baz() }, -3);
+        assert_eq!(unsafe { qux() }, -4);
+
+        #[allow(clashing_extern_declarations)]
+        {
+            extern "Rust" {
+                fn foo() -> i32;
+            }
+
+            assert_eq!(
+                unsafe {
+                    std::mem::transmute::<unsafe fn() -> i32, unsafe extern "C" fn() -> i32>(foo)()
+                },
+                -1
+            );
+
+            extern "C" {
+                fn bar() -> i32;
+                fn baz() -> i32;
+                fn qux() -> i32;
+            }
+
+            unsafe {
+                let transmute =
+                    |f| std::mem::transmute::<unsafe extern "C" fn() -> i32, unsafe fn() -> i32>(f);
+                assert_eq!(transmute(bar)(), -2);
+                assert_eq!(transmute(baz)(), -3);
+                assert_eq!(transmute(qux)(), -4);
+            }
+        }
+    }
+}
diff --git a/src/tools/miri/tests/pass/function_pointers.rs b/src/tools/miri/tests/pass/function_pointers.rs
new file mode 100644
index 000000000000..b66826e3fcdf
--- /dev/null
+++ b/src/tools/miri/tests/pass/function_pointers.rs
@@ -0,0 +1,89 @@
+use std::mem;
+
+trait Answer {
+    fn answer() -> Self;
+}
+
+impl Answer for i32 {
+    fn answer() -> i32 {
+        42
+    }
+}
+
+// A generic function, to make its address unstable
+fn f<T: Answer>() -> T {
+    Answer::answer()
+}
+
+fn g(i: i32) -> i32 {
+    i * 42
+}
+
+fn h(i: i32, j: i32) -> i32 {
+    j * i * 7
+}
+
+fn return_fn_ptr(f: fn() -> i32) -> fn() -> i32 {
+    f
+}
+
+fn call_fn_ptr() -> i32 {
+    return_fn_ptr(f)()
+}
+
+fn indirect<F: Fn() -> i32>(f: F) -> i32 {
+    f()
+}
+fn indirect_mut<F: FnMut() -> i32>(mut f: F) -> i32 {
+    f()
+}
+fn indirect_once<F: FnOnce() -> i32>(f: F) -> i32 {
+    f()
+}
+
+fn indirect2<F: Fn(i32) -> i32>(f: F) -> i32 {
+    f(10)
+}
+fn indirect_mut2<F: FnMut(i32) -> i32>(mut f: F) -> i32 {
+    f(10)
+}
+fn indirect_once2<F: FnOnce(i32) -> i32>(f: F) -> i32 {
+    f(10)
+}
+
+fn indirect3<F: Fn(i32, i32) -> i32>(f: F) -> i32 {
+    f(10, 3)
+}
+fn indirect_mut3<F: FnMut(i32, i32) -> i32>(mut f: F) -> i32 {
+    f(10, 3)
+}
+fn indirect_once3<F: FnOnce(i32, i32) -> i32>(f: F) -> i32 {
+    f(10, 3)
+}
+
+fn main() {
+    assert_eq!(call_fn_ptr(), 42);
+    assert_eq!(indirect(f), 42);
+    assert_eq!(indirect_mut(f), 42);
+    assert_eq!(indirect_once(f), 42);
+    assert_eq!(indirect2(g), 420);
+    assert_eq!(indirect_mut2(g), 420);
+    assert_eq!(indirect_once2(g), 420);
+    assert_eq!(indirect3(h), 210);
+    assert_eq!(indirect_mut3(h), 210);
+    assert_eq!(indirect_once3(h), 210);
+    let g = f as fn() -> i32;
+    assert!(return_fn_ptr(g) == g);
+    assert!(return_fn_ptr(g) as unsafe fn() -> i32 == g as fn() -> i32 as unsafe fn() -> i32);
+    assert!(return_fn_ptr(f) != f);
+
+    // Any non-null value is okay for function pointers.
+    unsafe {
+        let _x: fn() = mem::transmute(1usize);
+        let mut b = Box::new(42u8);
+        let ptr = &mut *b as *mut u8;
+        drop(b);
+        let _x: fn() = mem::transmute(ptr);
+        let _x: fn() = mem::transmute(ptr.wrapping_offset(1));
+    }
+}
diff --git a/src/tools/miri/tests/pass/generator.rs b/src/tools/miri/tests/pass/generator.rs
new file mode 100644
index 000000000000..06f48666c557
--- /dev/null
+++ b/src/tools/miri/tests/pass/generator.rs
@@ -0,0 +1,210 @@
+#![feature(generators, generator_trait, never_type)]
+
+use std::fmt::Debug;
+use std::mem::ManuallyDrop;
+use std::ops::{
+    Generator,
+    GeneratorState::{self, *},
+};
+use std::pin::Pin;
+use std::ptr;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+fn basic() {
+    fn finish<T>(mut amt: usize, mut t: T) -> T::Return
+    where
+        T: Generator<Yield = usize>,
+    {
+        // We are not moving the `t` around until it gets dropped, so this is okay.
+        let mut t = unsafe { Pin::new_unchecked(&mut t) };
+        loop {
+            let state = t.as_mut().resume(());
+            // Test if the generator is valid (according to type invariants).
+            let _ = unsafe { ManuallyDrop::new(ptr::read(t.as_mut().get_unchecked_mut())) };
+            match state {
+                GeneratorState::Yielded(y) => {
+                    amt -= y;
+                }
+                GeneratorState::Complete(ret) => {
+                    assert_eq!(amt, 0);
+                    return ret;
+                }
+            }
+        }
+    }
+
+    enum Never {}
+    fn never() -> Never {
+        panic!()
+    }
+
+    finish(1, || yield 1);
+
+    finish(3, || {
+        let mut x = 0;
+        yield 1;
+        x += 1;
+        yield 1;
+        x += 1;
+        yield 1;
+        assert_eq!(x, 2);
+    });
+
+    finish(7 * 8 / 2, || {
+        for i in 0..8 {
+            yield i;
+        }
+    });
+
+    finish(1, || {
+        if true {
+            yield 1;
+        } else {
+        }
+    });
+
+    finish(1, || {
+        if false {
+        } else {
+            yield 1;
+        }
+    });
+
+    finish(2, || {
+        if {
+            yield 1;
+            false
+        } {
+            yield 1;
+            panic!()
+        }
+        yield 1;
+    });
+
+    // also test a self-referential generator
+    assert_eq!(
+        finish(5, || {
+            let mut x = Box::new(5);
+            let y = &mut *x;
+            *y = 5;
+            yield *y;
+            *y = 10;
+            *x
+        }),
+        10
+    );
+
+    let b = true;
+    finish(1, || {
+        yield 1;
+        if b {
+            return;
+        }
+        #[allow(unused)]
+        let x = never();
+        #[allow(unreachable_code)]
+        yield 2;
+        drop(x);
+    });
+
+    finish(3, || {
+        yield 1;
+        #[allow(unreachable_code)]
+        let _x: (String, !) = (String::new(), {
+            yield 2;
+            return;
+        });
+    });
+}
+
+fn smoke_resume_arg() {
+    fn drain<G: Generator<R, Yield = Y> + Unpin, R, Y>(
+        gen: &mut G,
+        inout: Vec<(R, GeneratorState<Y, G::Return>)>,
+    ) where
+        Y: Debug + PartialEq,
+        G::Return: Debug + PartialEq,
+    {
+        let mut gen = Pin::new(gen);
+
+        for (input, out) in inout {
+            assert_eq!(gen.as_mut().resume(input), out);
+            // Test if the generator is valid (according to type invariants).
+            let _ = unsafe { ManuallyDrop::new(ptr::read(gen.as_mut().get_unchecked_mut())) };
+        }
+    }
+
+    static DROPS: AtomicUsize = AtomicUsize::new(0);
+
+    #[derive(Debug, PartialEq)]
+    struct DropMe;
+
+    impl Drop for DropMe {
+        fn drop(&mut self) {
+            DROPS.fetch_add(1, Ordering::SeqCst);
+        }
+    }
+
+    fn expect_drops<T>(expected_drops: usize, f: impl FnOnce() -> T) -> T {
+        DROPS.store(0, Ordering::SeqCst);
+
+        let res = f();
+
+        let actual_drops = DROPS.load(Ordering::SeqCst);
+        assert_eq!(actual_drops, expected_drops);
+        res
+    }
+
+    drain(
+        &mut |mut b| {
+            while b != 0 {
+                b = yield (b + 1);
+            }
+            -1
+        },
+        vec![(1, Yielded(2)), (-45, Yielded(-44)), (500, Yielded(501)), (0, Complete(-1))],
+    );
+
+    expect_drops(2, || drain(&mut |a| yield a, vec![(DropMe, Yielded(DropMe))]));
+
+    expect_drops(6, || {
+        drain(
+            &mut |a| yield yield a,
+            vec![(DropMe, Yielded(DropMe)), (DropMe, Yielded(DropMe)), (DropMe, Complete(DropMe))],
+        )
+    });
+
+    #[allow(unreachable_code)]
+    expect_drops(2, || drain(&mut |a| yield return a, vec![(DropMe, Complete(DropMe))]));
+
+    expect_drops(2, || {
+        drain(
+            &mut |a: DropMe| {
+                if false { yield () } else { a }
+            },
+            vec![(DropMe, Complete(DropMe))],
+        )
+    });
+
+    expect_drops(4, || {
+        drain(
+            #[allow(unused_assignments, unused_variables)]
+            &mut |mut a: DropMe| {
+                a = yield;
+                a = yield;
+                a = yield;
+            },
+            vec![
+                (DropMe, Yielded(())),
+                (DropMe, Yielded(())),
+                (DropMe, Yielded(())),
+                (DropMe, Complete(())),
+            ],
+        )
+    });
+}
+
+fn main() {
+    basic();
+    smoke_resume_arg();
+}
diff --git a/src/tools/miri/tests/pass/getpid.rs b/src/tools/miri/tests/pass/getpid.rs
new file mode 100644
index 000000000000..733545462ebc
--- /dev/null
+++ b/src/tools/miri/tests/pass/getpid.rs
@@ -0,0 +1,9 @@
+//@compile-flags: -Zmiri-disable-isolation
+
+fn getpid() -> u32 {
+    std::process::id()
+}
+
+fn main() {
+    getpid();
+}
diff --git a/src/tools/miri/tests/pass/global_allocator.rs b/src/tools/miri/tests/pass/global_allocator.rs
new file mode 100644
index 000000000000..24a56c663f06
--- /dev/null
+++ b/src/tools/miri/tests/pass/global_allocator.rs
@@ -0,0 +1,41 @@
+#![feature(allocator_api, slice_ptr_get)]
+
+use std::alloc::{Allocator as _, Global, GlobalAlloc, Layout, System};
+
+#[global_allocator]
+static ALLOCATOR: Allocator = Allocator;
+
+struct Allocator;
+
+unsafe impl GlobalAlloc for Allocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        // use specific size to avoid getting triggered by rt
+        if layout.size() == 123 {
+            println!("Allocated!")
+        }
+
+        System.alloc(layout)
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        if layout.size() == 123 {
+            println!("Dellocated!")
+        }
+
+        System.dealloc(ptr, layout)
+    }
+}
+
+fn main() {
+    // Only okay because we explicitly set a global allocator that uses the system allocator!
+    let l = Layout::from_size_align(123, 1).unwrap();
+    let ptr = Global.allocate(l).unwrap().as_non_null_ptr(); // allocating with Global...
+    unsafe {
+        System.deallocate(ptr, l);
+    } // ... and deallocating with System.
+
+    let ptr = System.allocate(l).unwrap().as_non_null_ptr(); // allocating with System...
+    unsafe {
+        Global.deallocate(ptr, l);
+    } // ... and deallocating with Global.
+}
diff --git a/src/tools/miri/tests/pass/global_allocator.stdout b/src/tools/miri/tests/pass/global_allocator.stdout
new file mode 100644
index 000000000000..411a4cdd1467
--- /dev/null
+++ b/src/tools/miri/tests/pass/global_allocator.stdout
@@ -0,0 +1,2 @@
+Allocated!
+Dellocated!
diff --git a/src/tools/miri/tests/pass/hashmap.rs b/src/tools/miri/tests/pass/hashmap.rs
new file mode 100644
index 000000000000..29ddd6c59a1a
--- /dev/null
+++ b/src/tools/miri/tests/pass/hashmap.rs
@@ -0,0 +1,40 @@
+use std::collections::HashMap;
+use std::hash::BuildHasher;
+
+// Gather all references from a mutable iterator and make sure Miri notices if
+// using them is dangerous.
+fn test_all_refs<'a, T: 'a>(dummy: &mut T, iter: impl Iterator<Item = &'a mut T>) {
+    // Gather all those references.
+    let mut refs: Vec<&mut T> = iter.collect();
+    // Use them all. Twice, to be sure we got all interleavings.
+    for r in refs.iter_mut() {
+        std::mem::swap(dummy, r);
+    }
+    for r in refs {
+        std::mem::swap(dummy, r);
+    }
+}
+
+fn smoketest_map<S: BuildHasher>(mut map: HashMap<i32, i32, S>) {
+    map.insert(0, 0);
+    assert_eq!(map.values().fold(0, |x, y| x + y), 0);
+
+    let num = 25;
+    for i in 1..num {
+        map.insert(i, i);
+    }
+    assert_eq!(map.values().fold(0, |x, y| x + y), num * (num - 1) / 2); // check the right things are in the table now
+
+    // Inserting again replaces the existing entries
+    for i in 0..num {
+        map.insert(i, num - 1 - i);
+    }
+    assert_eq!(map.values().fold(0, |x, y| x + y), num * (num - 1) / 2);
+
+    test_all_refs(&mut 13, map.values_mut());
+}
+
+fn main() {
+    // hashbrown uses Miri on its own CI; we just do a smoketest here.
+    smoketest_map(HashMap::new());
+}
diff --git a/src/tools/miri/tests/pass/heap.rs b/src/tools/miri/tests/pass/heap.rs
new file mode 100644
index 000000000000..44537e74b5a4
--- /dev/null
+++ b/src/tools/miri/tests/pass/heap.rs
@@ -0,0 +1,34 @@
+#![feature(box_syntax)]
+
+fn make_box() -> Box<(i16, i16)> {
+    Box::new((1, 2))
+}
+
+fn make_box_syntax() -> Box<(i16, i16)> {
+    box (1, 2)
+}
+
+fn allocate_reallocate() {
+    let mut s = String::new();
+
+    // 6 byte heap alloc (__rust_allocate)
+    s.push_str("foobar");
+    assert_eq!(s.len(), 6);
+    assert_eq!(s.capacity(), 8);
+
+    // heap size doubled to 12 (__rust_reallocate)
+    s.push_str("baz");
+    assert_eq!(s.len(), 9);
+    assert_eq!(s.capacity(), 16);
+
+    // heap size reduced to 9  (__rust_reallocate)
+    s.shrink_to_fit();
+    assert_eq!(s.len(), 9);
+    assert_eq!(s.capacity(), 9);
+}
+
+fn main() {
+    assert_eq!(*make_box(), (1, 2));
+    assert_eq!(*make_box_syntax(), (1, 2));
+    allocate_reallocate();
+}
diff --git a/src/tools/miri/tests/pass/heap_allocator.rs b/src/tools/miri/tests/pass/heap_allocator.rs
new file mode 100644
index 000000000000..2c38dcb49f1c
--- /dev/null
+++ b/src/tools/miri/tests/pass/heap_allocator.rs
@@ -0,0 +1,127 @@
+#![feature(allocator_api, slice_ptr_get)]
+
+use std::alloc::{Allocator, Global, Layout, System};
+use std::ptr::NonNull;
+use std::slice;
+
+fn check_alloc<T: Allocator>(allocator: T) {
+    unsafe {
+        for &align in &[4, 8, 16, 32] {
+            let layout_20 = Layout::from_size_align(20, align).unwrap();
+            let layout_40 = Layout::from_size_align(40, 4 * align).unwrap();
+            let layout_10 = Layout::from_size_align(10, align / 2).unwrap();
+
+            for _ in 0..32 {
+                let a = allocator.allocate(layout_20).unwrap().as_non_null_ptr();
+                assert_eq!(
+                    a.as_ptr() as usize % layout_20.align(),
+                    0,
+                    "pointer is incorrectly aligned",
+                );
+                allocator.deallocate(a, layout_20);
+            }
+
+            let p1 = allocator.allocate_zeroed(layout_20).unwrap().as_non_null_ptr();
+            assert_eq!(
+                p1.as_ptr() as usize % layout_20.align(),
+                0,
+                "pointer is incorrectly aligned",
+            );
+            assert_eq!(*p1.as_ptr(), 0);
+
+            // old size < new size
+            let p2 = allocator.grow(p1, layout_20, layout_40).unwrap().as_non_null_ptr();
+            assert_eq!(
+                p2.as_ptr() as usize % layout_40.align(),
+                0,
+                "pointer is incorrectly aligned",
+            );
+            let slice = slice::from_raw_parts(p2.as_ptr(), 20);
+            assert_eq!(&slice, &[0_u8; 20]);
+
+            // old size == new size
+            let p3 = allocator.grow(p2, layout_40, layout_40).unwrap().as_non_null_ptr();
+            assert_eq!(
+                p3.as_ptr() as usize % layout_40.align(),
+                0,
+                "pointer is incorrectly aligned",
+            );
+            let slice = slice::from_raw_parts(p3.as_ptr(), 20);
+            assert_eq!(&slice, &[0_u8; 20]);
+
+            // old size > new size
+            let p4 = allocator.shrink(p3, layout_40, layout_10).unwrap().as_non_null_ptr();
+            assert_eq!(
+                p4.as_ptr() as usize % layout_10.align(),
+                0,
+                "pointer is incorrectly aligned",
+            );
+            let slice = slice::from_raw_parts(p4.as_ptr(), 10);
+            assert_eq!(&slice, &[0_u8; 10]);
+
+            allocator.deallocate(p4, layout_10);
+        }
+    }
+}
+
+fn check_align_requests<T: Allocator>(allocator: T) {
+    #[rustfmt::skip] // https://github.com/rust-lang/rustfmt/issues/3255
+    for &size in &[2, 8, 64] { // size less than and bigger than alignment
+        for &align in &[4, 8, 16, 32] { // Be sure to cover less than and bigger than `MIN_ALIGN` for all architectures
+            let iterations = 32;
+            unsafe {
+                let pointers: Vec<_> = (0..iterations)
+                    .map(|_| {
+                        allocator
+                            .allocate(Layout::from_size_align(size, align).unwrap())
+                            .unwrap()
+                            .as_non_null_ptr()
+                    })
+                    .collect();
+                for &ptr in &pointers {
+                    assert_eq!(
+                        (ptr.as_ptr() as usize) % align,
+                        0,
+                        "Got a pointer less aligned than requested",
+                    )
+                }
+
+                // Clean up.
+                for &ptr in &pointers {
+                    allocator.deallocate(ptr, Layout::from_size_align(size, align).unwrap())
+                }
+            }
+        }
+    };
+}
+
+fn global_to_box() {
+    type T = [i32; 4];
+    let l = Layout::new::<T>();
+    // allocate manually with global allocator, then turn into Box and free there
+    unsafe {
+        let ptr = Global.allocate(l).unwrap().as_non_null_ptr().as_ptr() as *mut T;
+        let b = Box::from_raw(ptr);
+        drop(b);
+    }
+}
+
+fn box_to_global() {
+    type T = [i32; 4];
+    let l = Layout::new::<T>();
+    // allocate with the Box, then deallocate manually with global allocator
+    unsafe {
+        let b = Box::new(T::default());
+        let ptr = Box::into_raw(b);
+        Global.deallocate(NonNull::new(ptr as *mut u8).unwrap(), l);
+    }
+}
+
+fn main() {
+    check_alloc(System);
+    check_alloc(Global);
+    check_align_requests(System);
+    check_align_requests(Global);
+    global_to_box();
+    box_to_global();
+}
diff --git a/src/tools/miri/tests/pass/hello.rs b/src/tools/miri/tests/pass/hello.rs
new file mode 100644
index 000000000000..e7a11a969c03
--- /dev/null
+++ b/src/tools/miri/tests/pass/hello.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}
diff --git a/src/tools/miri/tests/pass/hello.stdout b/src/tools/miri/tests/pass/hello.stdout
new file mode 100644
index 000000000000..af5626b4a114
--- /dev/null
+++ b/src/tools/miri/tests/pass/hello.stdout
@@ -0,0 +1 @@
+Hello, world!
diff --git a/src/tools/miri/tests/pass/hide_stdout.rs b/src/tools/miri/tests/pass/hide_stdout.rs
new file mode 100644
index 000000000000..cfd05a8396cb
--- /dev/null
+++ b/src/tools/miri/tests/pass/hide_stdout.rs
@@ -0,0 +1,6 @@
+//@compile-flags: -Zmiri-mute-stdout-stderr
+
+fn main() {
+    println!("print to stdout");
+    eprintln!("print to stderr");
+}
diff --git a/src/tools/miri/tests/pass/integer-ops.rs b/src/tools/miri/tests/pass/integer-ops.rs
new file mode 100644
index 000000000000..724be9efc9f8
--- /dev/null
+++ b/src/tools/miri/tests/pass/integer-ops.rs
@@ -0,0 +1,205 @@
+//@compile-flags: -Coverflow-checks=off
+#![feature(int_log)]
+#![allow(arithmetic_overflow)]
+
+pub fn main() {
+    // This tests that we do (not) do sign extension properly when loading integers
+    assert_eq!(u32::MAX as i64, 4294967295);
+    assert_eq!(i32::MIN as i64, -2147483648);
+
+    assert_eq!(i8::MAX, 127);
+    assert_eq!(i8::MIN, -128);
+
+    // Shifts with negative offsets are subtle.
+    assert_eq!(13 << -2i8, 13 << 254);
+    assert_eq!(13 << i8::MIN, 13);
+    assert_eq!(13 << -1i16, 13 << u16::MAX);
+    assert_eq!(13 << i16::MIN, 13);
+    assert_eq!(13i128 << -2i8, 13i128 << 254);
+    assert_eq!(13i128 << i8::MIN, 13);
+    assert_eq!(13i128 << -1i16, 13i128 << u16::MAX);
+    assert_eq!(13i128 << i16::MIN, 13);
+
+    assert_eq!(i32::from_str_radix("A", 16), Ok(10));
+
+    let n = -0b1000_0000i8;
+    assert_eq!(n.count_ones(), 1);
+
+    let n = -0b1000_0000i8;
+    assert_eq!(n.count_zeros(), 7);
+
+    let n = -1i16;
+    assert_eq!(n.leading_zeros(), 0);
+
+    let n = -4i8;
+    assert_eq!(n.trailing_zeros(), 2);
+
+    let n = 0x0123456789ABCDEFi64;
+    let m = -0x76543210FEDCBA99i64;
+    assert_eq!(n.rotate_left(32), m);
+
+    let n = 0x0123456789ABCDEFi64;
+    let m = -0xFEDCBA987654322i64;
+    assert_eq!(n.rotate_right(4), m);
+
+    let n = 0x0123456789ABCDEFi64;
+    let m = -0x1032547698BADCFFi64;
+    assert_eq!(n.swap_bytes(), m);
+
+    let n = 0x0123456789ABCDEFi64;
+    if cfg!(target_endian = "big") {
+        assert_eq!(i64::from_be(n), n)
+    } else {
+        assert_eq!(i64::from_be(n), n.swap_bytes())
+    }
+
+    let n = 0x0123456789ABCDEFi64;
+    if cfg!(target_endian = "little") {
+        assert_eq!(i64::from_le(n), n)
+    } else {
+        assert_eq!(i64::from_le(n), n.swap_bytes())
+    }
+
+    let n = 0x0123456789ABCDEFi64;
+    if cfg!(target_endian = "big") {
+        assert_eq!(n.to_be(), n)
+    } else {
+        assert_eq!(n.to_be(), n.swap_bytes())
+    }
+
+    let n = 0x0123456789ABCDEFi64;
+    if cfg!(target_endian = "little") {
+        assert_eq!(n.to_le(), n)
+    } else {
+        assert_eq!(n.to_le(), n.swap_bytes())
+    }
+
+    assert_eq!(7i16.checked_add(32760), Some(32767));
+    assert_eq!(8i16.checked_add(32760), None);
+
+    assert_eq!((-127i8).checked_sub(1), Some(-128));
+    assert_eq!((-128i8).checked_sub(1), None);
+
+    assert_eq!(6i8.checked_mul(21), Some(126));
+    assert_eq!(6i8.checked_mul(22), None);
+
+    assert_eq!((-127i8).checked_div(-1), Some(127));
+    assert_eq!((-128i8).checked_div(-1), None);
+    assert_eq!((1i8).checked_div(0), None);
+
+    assert_eq!(5i32.checked_rem(2), Some(1));
+    assert_eq!(5i32.checked_rem(0), None);
+    assert_eq!(i32::MIN.checked_rem(-1), None);
+
+    assert_eq!(5i32.checked_neg(), Some(-5));
+    assert_eq!(i32::MIN.checked_neg(), None);
+
+    assert_eq!(0x10i32.checked_shl(4), Some(0x100));
+    assert_eq!(0x10i32.checked_shl(33), None);
+
+    assert_eq!(0x10i32.checked_shr(4), Some(0x1));
+    assert_eq!(0x10i32.checked_shr(33), None);
+
+    assert_eq!((-5i32).checked_abs(), Some(5));
+    assert_eq!(i32::MIN.checked_abs(), None);
+
+    assert_eq!(100i8.saturating_add(1), 101);
+    assert_eq!(100i8.saturating_add(127), 127);
+
+    assert_eq!(100i8.saturating_sub(127), -27);
+    assert_eq!((-100i8).saturating_sub(127), -128);
+
+    assert_eq!(100i32.saturating_mul(127), 12700);
+    assert_eq!((1i32 << 23).saturating_mul(1 << 23), i32::MAX);
+    assert_eq!((-1i32 << 23).saturating_mul(1 << 23), i32::MIN);
+
+    assert_eq!(100i8.wrapping_add(27), 127);
+    assert_eq!(100i8.wrapping_add(127), -29);
+
+    assert_eq!(0i8.wrapping_sub(127), -127);
+    assert_eq!((-2i8).wrapping_sub(127), 127);
+
+    assert_eq!(10i8.wrapping_mul(12), 120);
+    assert_eq!(11i8.wrapping_mul(12), -124);
+
+    assert_eq!(100u8.wrapping_div(10), 10);
+    assert_eq!((-128i8).wrapping_div(-1), -128);
+
+    assert_eq!(100i8.wrapping_rem(10), 0);
+    assert_eq!((-128i8).wrapping_rem(-1), 0);
+
+    assert_eq!(i32::MIN.wrapping_div(-1), i32::MIN);
+    assert_eq!(i32::MIN.wrapping_rem(-1), 0);
+
+    assert_eq!(100i8.wrapping_neg(), -100);
+    assert_eq!((-128i8).wrapping_neg(), -128);
+
+    assert_eq!((-1i8).wrapping_shl(7), -128);
+    assert_eq!((-1i8).wrapping_shl(8), -1);
+
+    assert_eq!((-128i8).wrapping_shr(7), -1);
+    assert_eq!((-128i8).wrapping_shr(8), -128);
+
+    assert_eq!(100i8.wrapping_abs(), 100);
+    assert_eq!((-100i8).wrapping_abs(), 100);
+    assert_eq!((-128i8).wrapping_abs(), -128);
+    assert_eq!((-128i8).wrapping_abs() as u8, 128);
+
+    assert_eq!(5i32.overflowing_add(2), (7, false));
+    assert_eq!(i32::MAX.overflowing_add(1), (i32::MIN, true));
+
+    assert_eq!(5i32.overflowing_sub(2), (3, false));
+    assert_eq!(i32::MIN.overflowing_sub(1), (i32::MAX, true));
+
+    assert_eq!(5i32.overflowing_mul(2), (10, false));
+    assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
+
+    assert_eq!(5i32.overflowing_div(2), (2, false));
+    assert_eq!(i32::MIN.overflowing_div(-1), (i32::MIN, true));
+
+    assert_eq!(5i32.overflowing_rem(2), (1, false));
+    assert_eq!(i32::MIN.overflowing_rem(-1), (0, true));
+
+    assert_eq!(2i32.overflowing_neg(), (-2, false));
+    assert_eq!(i32::MIN.overflowing_neg(), (i32::MIN, true));
+
+    assert_eq!(0x10i32.overflowing_shl(4), (0x100, false));
+    assert_eq!(0x10i32.overflowing_shl(36), (0x100, true));
+
+    assert_eq!(0x10i32.overflowing_shr(4), (0x1, false));
+    assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
+
+    assert_eq!(10i8.overflowing_abs(), (10, false));
+    assert_eq!((-10i8).overflowing_abs(), (10, false));
+    assert_eq!((-128i8).overflowing_abs(), (-128, true));
+
+    // Logarithms
+    macro_rules! test_log {
+        ($type:ident, $max_log2:expr, $max_log10:expr) => {
+            assert_eq!($type::MIN.checked_ilog2(), None);
+            assert_eq!($type::MIN.checked_ilog10(), None);
+            assert_eq!($type::MAX.checked_ilog2(), Some($max_log2));
+            assert_eq!($type::MAX.checked_ilog10(), Some($max_log10));
+            assert_eq!($type::MAX.ilog2(), $max_log2);
+            assert_eq!($type::MAX.ilog10(), $max_log10);
+        };
+    }
+
+    test_log!(i8, 6, 2);
+    test_log!(u8, 7, 2);
+    test_log!(i16, 14, 4);
+    test_log!(u16, 15, 4);
+    test_log!(i32, 30, 9);
+    test_log!(u32, 31, 9);
+    test_log!(i64, 62, 18);
+    test_log!(u64, 63, 19);
+    test_log!(i128, 126, 38);
+    test_log!(u128, 127, 38);
+
+    for i in (1..=i16::MAX).step_by(i8::MAX as usize) {
+        assert_eq!(i.checked_ilog(13), Some((i as f32).log(13.0) as u32));
+    }
+    for i in (1..=u16::MAX).step_by(i8::MAX as usize) {
+        assert_eq!(i.checked_ilog(13), Some((i as f32).log(13.0) as u32));
+    }
+}
diff --git a/src/tools/miri/tests/pass/intptrcast.rs b/src/tools/miri/tests/pass/intptrcast.rs
new file mode 100644
index 000000000000..e7ff90cb6bf0
--- /dev/null
+++ b/src/tools/miri/tests/pass/intptrcast.rs
@@ -0,0 +1,163 @@
+//@compile-flags: -Zmiri-permissive-provenance
+
+use std::mem;
+
+// This strips provenance
+fn transmute_ptr_to_int<T>(x: *const T) -> usize {
+    unsafe { std::mem::transmute(x) }
+}
+
+fn cast() {
+    // Some casting-to-int with arithmetic.
+    let x = &42 as *const i32 as usize;
+    let y = x * 2;
+    assert_eq!(y, x + x);
+    let z = y as u8 as usize;
+    assert_eq!(z, y % 256);
+}
+
+/// Test usize->ptr cast for dangling and OOB address.
+/// That is safe, and thus has to work.
+fn cast_dangling() {
+    let b = Box::new(0);
+    let x = &*b as *const i32 as usize;
+    drop(b);
+    let _val = x as *const i32;
+
+    let b = Box::new(0);
+    let mut x = &*b as *const i32 as usize;
+    x += 0x100;
+    let _val = x as *const i32;
+}
+
+fn format() {
+    // Pointer string formatting! We can't check the output as it changes when libstd changes,
+    // but we can make sure Miri does not error.
+    format!("{:?}", &mut 13 as *mut _);
+}
+
+fn transmute() {
+    // Check that intptrcast is triggered for explicit casts and that it is consistent with
+    // transmuting.
+    let a: *const i32 = &42;
+    let b = transmute_ptr_to_int(a) as u8;
+    let c = a as u8;
+    assert_eq!(b, c);
+}
+
+fn ptr_bitops1() {
+    let bytes = [0i8, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+    let one = bytes.as_ptr().wrapping_offset(1);
+    let three = bytes.as_ptr().wrapping_offset(3);
+    let res = (one as usize) | (three as usize);
+    format!("{}", res);
+}
+
+fn ptr_bitops2() {
+    let val = 13usize;
+    let addr = &val as *const _ as usize;
+    let _val = addr & 13;
+}
+
+fn ptr_eq_dangling() {
+    let b = Box::new(0);
+    let x = &*b as *const i32; // soon-to-be dangling
+    drop(b);
+    let b = Box::new(0);
+    let y = &*b as *const i32; // different allocation
+    // They *could* be equal if memory was reused, but probably are not.
+    assert!(x != y);
+}
+
+fn ptr_eq_out_of_bounds() {
+    let b = Box::new(0);
+    let x = (&*b as *const i32).wrapping_sub(0x800); // out-of-bounds
+    let b = Box::new(0);
+    let y = &*b as *const i32; // different allocation
+    // They *could* be equal (with the right base addresses), but probably are not.
+    assert!(x != y);
+}
+
+fn ptr_eq_out_of_bounds_null() {
+    let b = Box::new(0);
+    let x = (&*b as *const i32).wrapping_sub(0x800); // out-of-bounds
+    // This *could* be NULL (with the right base address), but probably is not.
+    assert!(x != std::ptr::null());
+}
+
+fn ptr_eq_integer() {
+    let b = Box::new(0);
+    let x = &*b as *const i32;
+    // These *could* be equal (with the right base address), but probably are not.
+    assert!(x != 64 as *const i32);
+}
+
+fn zst_deref_of_dangling() {
+    let b = Box::new(0);
+    let addr = &*b as *const _ as usize;
+    drop(b);
+    // Now if we cast `addr` to a ptr it might pick up the dangling provenance.
+    // But if we only do a ZST deref there is no UB here!
+    let zst = addr as *const ();
+    let _val = unsafe { *zst };
+}
+
+fn functions() {
+    // Roundtrip a few functions through integers. Do this multiple times to make sure this does not
+    // work by chance. If we did not give unique addresses to ZST allocations -- which fn
+    // allocations are -- then we might be unable to cast back, or we might call the wrong function!
+    // Every function gets at most one address so doing a loop would not help...
+    fn fn0() -> i32 {
+        0
+    }
+    fn fn1() -> i32 {
+        1
+    }
+    fn fn2() -> i32 {
+        2
+    }
+    fn fn3() -> i32 {
+        3
+    }
+    fn fn4() -> i32 {
+        4
+    }
+    fn fn5() -> i32 {
+        5
+    }
+    fn fn6() -> i32 {
+        6
+    }
+    fn fn7() -> i32 {
+        7
+    }
+    let fns = [
+        fn0 as fn() -> i32 as *const () as usize,
+        fn1 as fn() -> i32 as *const () as usize,
+        fn2 as fn() -> i32 as *const () as usize,
+        fn3 as fn() -> i32 as *const () as usize,
+        fn4 as fn() -> i32 as *const () as usize,
+        fn5 as fn() -> i32 as *const () as usize,
+        fn6 as fn() -> i32 as *const () as usize,
+        fn7 as fn() -> i32 as *const () as usize,
+    ];
+    for (idx, &addr) in fns.iter().enumerate() {
+        let fun: fn() -> i32 = unsafe { mem::transmute(addr as *const ()) };
+        assert_eq!(fun(), idx as i32);
+    }
+}
+
+fn main() {
+    cast();
+    cast_dangling();
+    format();
+    transmute();
+    ptr_bitops1();
+    ptr_bitops2();
+    ptr_eq_dangling();
+    ptr_eq_out_of_bounds();
+    ptr_eq_out_of_bounds_null();
+    ptr_eq_integer();
+    zst_deref_of_dangling();
+    functions();
+}
diff --git a/src/tools/miri/tests/pass/intrinsics-integer.rs b/src/tools/miri/tests/pass/intrinsics-integer.rs
new file mode 100644
index 000000000000..546931f6ff87
--- /dev/null
+++ b/src/tools/miri/tests/pass/intrinsics-integer.rs
@@ -0,0 +1,154 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(core_intrinsics)]
+use std::intrinsics::*;
+
+pub fn main() {
+    unsafe {
+        [assert_eq!(ctpop(0u8), 0), assert_eq!(ctpop(0i8), 0)];
+        [assert_eq!(ctpop(0u16), 0), assert_eq!(ctpop(0i16), 0)];
+        [assert_eq!(ctpop(0u32), 0), assert_eq!(ctpop(0i32), 0)];
+        [assert_eq!(ctpop(0u64), 0), assert_eq!(ctpop(0i64), 0)];
+
+        [assert_eq!(ctpop(1u8), 1), assert_eq!(ctpop(1i8), 1)];
+        [assert_eq!(ctpop(1u16), 1), assert_eq!(ctpop(1i16), 1)];
+        [assert_eq!(ctpop(1u32), 1), assert_eq!(ctpop(1i32), 1)];
+        [assert_eq!(ctpop(1u64), 1), assert_eq!(ctpop(1i64), 1)];
+
+        [assert_eq!(ctpop(10u8), 2), assert_eq!(ctpop(10i8), 2)];
+        [assert_eq!(ctpop(10u16), 2), assert_eq!(ctpop(10i16), 2)];
+        [assert_eq!(ctpop(10u32), 2), assert_eq!(ctpop(10i32), 2)];
+        [assert_eq!(ctpop(10u64), 2), assert_eq!(ctpop(10i64), 2)];
+
+        [assert_eq!(ctpop(100u8), 3), assert_eq!(ctpop(100i8), 3)];
+        [assert_eq!(ctpop(100u16), 3), assert_eq!(ctpop(100i16), 3)];
+        [assert_eq!(ctpop(100u32), 3), assert_eq!(ctpop(100i32), 3)];
+        [assert_eq!(ctpop(100u64), 3), assert_eq!(ctpop(100i64), 3)];
+
+        [assert_eq!(ctpop(-1i8 as u8), 8), assert_eq!(ctpop(-1i8), 8)];
+        [assert_eq!(ctpop(-1i16 as u16), 16), assert_eq!(ctpop(-1i16), 16)];
+        [assert_eq!(ctpop(-1i32 as u32), 32), assert_eq!(ctpop(-1i32), 32)];
+        [assert_eq!(ctpop(-1i64 as u64), 64), assert_eq!(ctpop(-1i64), 64)];
+
+        [assert_eq!(ctlz(0u8), 8), assert_eq!(ctlz(0i8), 8)];
+        [assert_eq!(ctlz(0u16), 16), assert_eq!(ctlz(0i16), 16)];
+        [assert_eq!(ctlz(0u32), 32), assert_eq!(ctlz(0i32), 32)];
+        [assert_eq!(ctlz(0u64), 64), assert_eq!(ctlz(0i64), 64)];
+
+        [assert_eq!(ctlz(1u8), 7), assert_eq!(ctlz(1i8), 7)];
+        [assert_eq!(ctlz(1u16), 15), assert_eq!(ctlz(1i16), 15)];
+        [assert_eq!(ctlz(1u32), 31), assert_eq!(ctlz(1i32), 31)];
+        [assert_eq!(ctlz(1u64), 63), assert_eq!(ctlz(1i64), 63)];
+
+        [assert_eq!(ctlz(10u8), 4), assert_eq!(ctlz(10i8), 4)];
+        [assert_eq!(ctlz(10u16), 12), assert_eq!(ctlz(10i16), 12)];
+        [assert_eq!(ctlz(10u32), 28), assert_eq!(ctlz(10i32), 28)];
+        [assert_eq!(ctlz(10u64), 60), assert_eq!(ctlz(10i64), 60)];
+
+        [assert_eq!(ctlz(100u8), 1), assert_eq!(ctlz(100i8), 1)];
+        [assert_eq!(ctlz(100u16), 9), assert_eq!(ctlz(100i16), 9)];
+        [assert_eq!(ctlz(100u32), 25), assert_eq!(ctlz(100i32), 25)];
+        [assert_eq!(ctlz(100u64), 57), assert_eq!(ctlz(100i64), 57)];
+
+        [assert_eq!(ctlz_nonzero(1u8), 7), assert_eq!(ctlz_nonzero(1i8), 7)];
+        [assert_eq!(ctlz_nonzero(1u16), 15), assert_eq!(ctlz_nonzero(1i16), 15)];
+        [assert_eq!(ctlz_nonzero(1u32), 31), assert_eq!(ctlz_nonzero(1i32), 31)];
+        [assert_eq!(ctlz_nonzero(1u64), 63), assert_eq!(ctlz_nonzero(1i64), 63)];
+
+        [assert_eq!(ctlz_nonzero(10u8), 4), assert_eq!(ctlz_nonzero(10i8), 4)];
+        [assert_eq!(ctlz_nonzero(10u16), 12), assert_eq!(ctlz_nonzero(10i16), 12)];
+        [assert_eq!(ctlz_nonzero(10u32), 28), assert_eq!(ctlz_nonzero(10i32), 28)];
+        [assert_eq!(ctlz_nonzero(10u64), 60), assert_eq!(ctlz_nonzero(10i64), 60)];
+
+        [assert_eq!(ctlz_nonzero(100u8), 1), assert_eq!(ctlz_nonzero(100i8), 1)];
+        [assert_eq!(ctlz_nonzero(100u16), 9), assert_eq!(ctlz_nonzero(100i16), 9)];
+        [assert_eq!(ctlz_nonzero(100u32), 25), assert_eq!(ctlz_nonzero(100i32), 25)];
+        [assert_eq!(ctlz_nonzero(100u64), 57), assert_eq!(ctlz_nonzero(100i64), 57)];
+
+        [assert_eq!(cttz(-1i8 as u8), 0), assert_eq!(cttz(-1i8), 0)];
+        [assert_eq!(cttz(-1i16 as u16), 0), assert_eq!(cttz(-1i16), 0)];
+        [assert_eq!(cttz(-1i32 as u32), 0), assert_eq!(cttz(-1i32), 0)];
+        [assert_eq!(cttz(-1i64 as u64), 0), assert_eq!(cttz(-1i64), 0)];
+
+        [assert_eq!(cttz(0u8), 8), assert_eq!(cttz(0i8), 8)];
+        [assert_eq!(cttz(0u16), 16), assert_eq!(cttz(0i16), 16)];
+        [assert_eq!(cttz(0u32), 32), assert_eq!(cttz(0i32), 32)];
+        [assert_eq!(cttz(0u64), 64), assert_eq!(cttz(0i64), 64)];
+
+        [assert_eq!(cttz(1u8), 0), assert_eq!(cttz(1i8), 0)];
+        [assert_eq!(cttz(1u16), 0), assert_eq!(cttz(1i16), 0)];
+        [assert_eq!(cttz(1u32), 0), assert_eq!(cttz(1i32), 0)];
+        [assert_eq!(cttz(1u64), 0), assert_eq!(cttz(1i64), 0)];
+
+        [assert_eq!(cttz(10u8), 1), assert_eq!(cttz(10i8), 1)];
+        [assert_eq!(cttz(10u16), 1), assert_eq!(cttz(10i16), 1)];
+        [assert_eq!(cttz(10u32), 1), assert_eq!(cttz(10i32), 1)];
+        [assert_eq!(cttz(10u64), 1), assert_eq!(cttz(10i64), 1)];
+
+        [assert_eq!(cttz(100u8), 2), assert_eq!(cttz(100i8), 2)];
+        [assert_eq!(cttz(100u16), 2), assert_eq!(cttz(100i16), 2)];
+        [assert_eq!(cttz(100u32), 2), assert_eq!(cttz(100i32), 2)];
+        [assert_eq!(cttz(100u64), 2), assert_eq!(cttz(100i64), 2)];
+
+        [assert_eq!(cttz_nonzero(-1i8 as u8), 0), assert_eq!(cttz_nonzero(-1i8), 0)];
+        [assert_eq!(cttz_nonzero(-1i16 as u16), 0), assert_eq!(cttz_nonzero(-1i16), 0)];
+        [assert_eq!(cttz_nonzero(-1i32 as u32), 0), assert_eq!(cttz_nonzero(-1i32), 0)];
+        [assert_eq!(cttz_nonzero(-1i64 as u64), 0), assert_eq!(cttz_nonzero(-1i64), 0)];
+
+        [assert_eq!(cttz_nonzero(1u8), 0), assert_eq!(cttz_nonzero(1i8), 0)];
+        [assert_eq!(cttz_nonzero(1u16), 0), assert_eq!(cttz_nonzero(1i16), 0)];
+        [assert_eq!(cttz_nonzero(1u32), 0), assert_eq!(cttz_nonzero(1i32), 0)];
+        [assert_eq!(cttz_nonzero(1u64), 0), assert_eq!(cttz_nonzero(1i64), 0)];
+
+        [assert_eq!(cttz_nonzero(10u8), 1), assert_eq!(cttz_nonzero(10i8), 1)];
+        [assert_eq!(cttz_nonzero(10u16), 1), assert_eq!(cttz_nonzero(10i16), 1)];
+        [assert_eq!(cttz_nonzero(10u32), 1), assert_eq!(cttz_nonzero(10i32), 1)];
+        [assert_eq!(cttz_nonzero(10u64), 1), assert_eq!(cttz_nonzero(10i64), 1)];
+
+        [assert_eq!(cttz_nonzero(100u8), 2), assert_eq!(cttz_nonzero(100i8), 2)];
+        [assert_eq!(cttz_nonzero(100u16), 2), assert_eq!(cttz_nonzero(100i16), 2)];
+        [assert_eq!(cttz_nonzero(100u32), 2), assert_eq!(cttz_nonzero(100i32), 2)];
+        [assert_eq!(cttz_nonzero(100u64), 2), assert_eq!(cttz_nonzero(100i64), 2)];
+
+        assert_eq!(bswap(0x0Au8), 0x0A); // no-op
+        assert_eq!(bswap(0x0Ai8), 0x0A); // no-op
+        assert_eq!(bswap(0x0A0Bu16), 0x0B0A);
+        assert_eq!(bswap(0x0A0Bi16), 0x0B0A);
+        assert_eq!(bswap(0x0ABBCC0Du32), 0x0DCCBB0A);
+        assert_eq!(bswap(0x0ABBCC0Di32), 0x0DCCBB0A);
+        assert_eq!(bswap(0x0122334455667708u64), 0x0877665544332201);
+        assert_eq!(bswap(0x0122334455667708i64), 0x0877665544332201);
+
+        assert_eq!(exact_div(9 * 9u32, 3), 27);
+        assert_eq!(exact_div(-9 * 9i32, 3), -27);
+        assert_eq!(exact_div(9 * 9i8, -3), -27);
+        assert_eq!(exact_div(-9 * 9i64, -3), 27);
+
+        assert_eq!(unchecked_div(9 * 9u32, 2), 40);
+        assert_eq!(unchecked_div(-9 * 9i32, 2), -40);
+        assert_eq!(unchecked_div(9 * 9i8, -2), -40);
+        assert_eq!(unchecked_div(-9 * 9i64, -2), 40);
+
+        assert_eq!(unchecked_rem(9 * 9u32, 2), 1);
+        assert_eq!(unchecked_rem(-9 * 9i32, 2), -1);
+        assert_eq!(unchecked_rem(9 * 9i8, -2), 1);
+        assert_eq!(unchecked_rem(-9 * 9i64, -2), -1);
+
+        assert_eq!(unchecked_add(23u8, 19), 42);
+        assert_eq!(unchecked_add(5, -10), -5);
+
+        assert_eq!(unchecked_sub(23u8, 19), 4);
+        assert_eq!(unchecked_sub(-17, -27), 10);
+
+        assert_eq!(unchecked_mul(6u8, 7), 42);
+        assert_eq!(unchecked_mul(13, -5), -65);
+    }
+}
diff --git a/src/tools/miri/tests/pass/intrinsics-math.rs b/src/tools/miri/tests/pass/intrinsics-math.rs
new file mode 100644
index 000000000000..5973f4cd197f
--- /dev/null
+++ b/src/tools/miri/tests/pass/intrinsics-math.rs
@@ -0,0 +1,140 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+macro_rules! assert_approx_eq {
+    ($a:expr, $b:expr) => {{
+        let (a, b) = (&$a, &$b);
+        assert!((*a - *b).abs() < 1.0e-6, "{} is not approximately equal to {}", *a, *b);
+    }};
+}
+
+fn ldexp(a: f64, b: i32) -> f64 {
+    extern "C" {
+        fn ldexp(x: f64, n: i32) -> f64;
+    }
+    unsafe { ldexp(a, b) }
+}
+
+pub fn main() {
+    use std::f32;
+    use std::f64;
+
+    assert_approx_eq!(64f32.sqrt(), 8f32);
+    assert_approx_eq!(64f64.sqrt(), 8f64);
+
+    assert_approx_eq!(25f32.powi(-2), 0.0016f32);
+    assert_approx_eq!(23.2f64.powi(2), 538.24f64);
+
+    assert_approx_eq!(25f32.powf(-2f32), 0.0016f32);
+    assert_approx_eq!(400f64.powf(0.5f64), 20f64);
+
+    assert_approx_eq!(1f32.exp(), f32::consts::E);
+    assert_approx_eq!(1f64.exp(), f64::consts::E);
+
+    assert_approx_eq!(1f32.exp_m1(), f32::consts::E - 1.0);
+    assert_approx_eq!(1f64.exp_m1(), f64::consts::E - 1.0);
+
+    assert_approx_eq!(10f32.exp2(), 1024f32);
+    assert_approx_eq!(50f64.exp2(), 1125899906842624f64);
+
+    assert_approx_eq!(f32::consts::E.ln(), 1f32);
+    assert_approx_eq!(1f64.ln(), 0f64);
+
+    assert_approx_eq!(0f32.ln_1p(), 0f32);
+    assert_approx_eq!(0f64.ln_1p(), 0f64);
+
+    assert_approx_eq!(10f32.log10(), 1f32);
+    assert_approx_eq!(f64::consts::E.log10(), f64::consts::LOG10_E);
+
+    assert_approx_eq!(8f32.log2(), 3f32);
+    assert_approx_eq!(f64::consts::E.log2(), f64::consts::LOG2_E);
+
+    assert_approx_eq!(3.0f32.mul_add(2.0f32, 5.0f32), 11.0);
+    assert_eq!(0.0f32.mul_add(-2.0, f32::consts::E), f32::consts::E);
+    assert_approx_eq!(3.0f64.mul_add(2.0, 5.0), 11.0);
+    assert_eq!(0.0f64.mul_add(-2.0f64, f64::consts::E), f64::consts::E);
+    assert_eq!((-3.2f32).mul_add(2.4, f32::NEG_INFINITY), f32::NEG_INFINITY);
+    assert_eq!((-3.2f64).mul_add(2.4, f64::NEG_INFINITY), f64::NEG_INFINITY);
+
+    assert_approx_eq!((-1.0f32).abs(), 1.0f32);
+    assert_approx_eq!(34.2f64.abs(), 34.2f64);
+
+    #[allow(deprecated)]
+    {
+        assert_approx_eq!(5.0f32.abs_sub(3.0), 2.0);
+        assert_approx_eq!(3.0f64.abs_sub(5.0), 0.0);
+    }
+
+    assert_approx_eq!(3.8f32.floor(), 3.0f32);
+    assert_approx_eq!((-1.1f64).floor(), -2.0f64);
+
+    assert_approx_eq!((-2.3f32).ceil(), -2.0f32);
+    assert_approx_eq!(3.8f64.ceil(), 4.0f64);
+
+    assert_approx_eq!(0.1f32.trunc(), 0.0f32);
+    assert_approx_eq!((-0.1f64).trunc(), 0.0f64);
+
+    assert_approx_eq!(27.0f32.cbrt(), 3.0f32);
+    assert_approx_eq!(27.0f64.cbrt(), 3.0f64);
+
+    assert_approx_eq!(3.0f32.hypot(4.0f32), 5.0f32);
+    assert_approx_eq!(3.0f64.hypot(4.0f64), 5.0f64);
+
+    assert_eq!(3.3_f32.round(), 3.0);
+    assert_eq!(3.3_f64.round(), 3.0);
+
+    assert_eq!(ldexp(0.65f64, 3i32), 5.2f64);
+    assert_eq!(ldexp(1.42, 0xFFFF), f64::INFINITY);
+    assert_eq!(ldexp(1.42, -0xFFFF), 0f64);
+
+    // Trigonometric functions.
+
+    assert_approx_eq!(0f32.sin(), 0f32);
+    assert_approx_eq!((f64::consts::PI / 2f64).sin(), 1f64);
+    assert_approx_eq!(f32::consts::FRAC_PI_6.sin(), 0.5);
+    assert_approx_eq!(f64::consts::FRAC_PI_6.sin(), 0.5);
+    assert_approx_eq!(f32::consts::FRAC_PI_4.sin().asin(), f32::consts::FRAC_PI_4);
+    assert_approx_eq!(f64::consts::FRAC_PI_4.sin().asin(), f64::consts::FRAC_PI_4);
+
+    assert_approx_eq!(1.0f32.sinh(), 1.1752012f32);
+    assert_approx_eq!(1.0f64.sinh(), 1.1752012f64);
+    assert_approx_eq!(2.0f32.asinh(), 1.443635475178810342493276740273105f32);
+    assert_approx_eq!((-2.0f64).asinh(), -1.443635475178810342493276740273105f64);
+
+    assert_approx_eq!(0f32.cos(), 1f32);
+    assert_approx_eq!((f64::consts::PI * 2f64).cos(), 1f64);
+    assert_approx_eq!(f32::consts::FRAC_PI_3.cos(), 0.5);
+    assert_approx_eq!(f64::consts::FRAC_PI_3.cos(), 0.5);
+    assert_approx_eq!(f32::consts::FRAC_PI_4.cos().acos(), f32::consts::FRAC_PI_4);
+    assert_approx_eq!(f64::consts::FRAC_PI_4.cos().acos(), f64::consts::FRAC_PI_4);
+
+    assert_approx_eq!(1.0f32.cosh(), 1.54308f32);
+    assert_approx_eq!(1.0f64.cosh(), 1.54308f64);
+    assert_approx_eq!(2.0f32.acosh(), 1.31695789692481670862504634730796844f32);
+    assert_approx_eq!(3.0f64.acosh(), 1.76274717403908605046521864995958461f64);
+
+    assert_approx_eq!(1.0f32.tan(), 1.557408f32);
+    assert_approx_eq!(1.0f64.tan(), 1.557408f64);
+    assert_approx_eq!(1.0_f32, 1.0_f32.tan().atan());
+    assert_approx_eq!(1.0_f64, 1.0_f64.tan().atan());
+    assert_approx_eq!(1.0f32.atan2(2.0f32), 0.46364761f32);
+    assert_approx_eq!(1.0f32.atan2(2.0f32), 0.46364761f32);
+
+    assert_approx_eq!(
+        1.0f32.tanh(),
+        (1.0 - f32::consts::E.powi(-2)) / (1.0 + f32::consts::E.powi(-2))
+    );
+    assert_approx_eq!(
+        1.0f64.tanh(),
+        (1.0 - f64::consts::E.powi(-2)) / (1.0 + f64::consts::E.powi(-2))
+    );
+    assert_approx_eq!(0.5f32.atanh(), 0.54930614433405484569762261846126285f32);
+    assert_approx_eq!(0.5f64.atanh(), 0.54930614433405484569762261846126285f64);
+}
diff --git a/src/tools/miri/tests/pass/intrinsics-x86.rs b/src/tools/miri/tests/pass/intrinsics-x86.rs
new file mode 100644
index 000000000000..88cd782e70a4
--- /dev/null
+++ b/src/tools/miri/tests/pass/intrinsics-x86.rs
@@ -0,0 +1,22 @@
+#[cfg(target_arch = "x86_64")]
+mod x86_64 {
+    use core::arch::x86_64 as arch;
+
+    fn adc(c_in: u8, a: u64, b: u64) -> (u8, u64) {
+        let mut sum = 0;
+        // SAFETY: There are no safety requirements for calling `_addcarry_u64`.
+        // It's just unsafe for API consistency with other intrinsics.
+        let c_out = unsafe { arch::_addcarry_u64(c_in, a, b, &mut sum) };
+        (c_out, sum)
+    }
+
+    pub fn main() {
+        assert_eq!(adc(1, 1, 1), (0, 3));
+        assert_eq!(adc(3, u64::MAX, u64::MAX), (2, 1));
+    }
+}
+
+fn main() {
+    #[cfg(target_arch = "x86_64")]
+    x86_64::main();
+}
diff --git a/src/tools/miri/tests/pass/intrinsics.rs b/src/tools/miri/tests/pass/intrinsics.rs
new file mode 100644
index 000000000000..6267e6e6bc11
--- /dev/null
+++ b/src/tools/miri/tests/pass/intrinsics.rs
@@ -0,0 +1,42 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(core_intrinsics, layout_for_ptr)]
+//! Tests for various intrinsics that do not fit anywhere else.
+
+use std::intrinsics;
+use std::mem::{size_of, size_of_val, size_of_val_raw};
+
+struct Bomb;
+
+impl Drop for Bomb {
+    fn drop(&mut self) {
+        eprintln!("BOOM!");
+    }
+}
+
+fn main() {
+    assert_eq!(size_of::<Option<i32>>(), 8);
+    assert_eq!(size_of_val(&()), 0);
+    assert_eq!(size_of_val(&42), 4);
+    assert_eq!(size_of_val(&[] as &[i32]), 0);
+    assert_eq!(size_of_val(&[1, 2, 3] as &[i32]), 12);
+    assert_eq!(size_of_val("foobar"), 6);
+
+    unsafe {
+        assert_eq!(size_of_val_raw(&[1] as &[i32] as *const [i32]), 4);
+    }
+    unsafe {
+        assert_eq!(size_of_val_raw(0x100 as *const i32), 4);
+    }
+
+    assert_eq!(intrinsics::type_name::<Option<i32>>(), "core::option::Option<i32>");
+
+    assert_eq!(intrinsics::likely(false), false);
+    assert_eq!(intrinsics::unlikely(true), true);
+
+    intrinsics::forget(Bomb);
+
+    let _v = intrinsics::discriminant_value(&Some(()));
+    let _v = intrinsics::discriminant_value(&0);
+    let _v = intrinsics::discriminant_value(&true);
+    let _v = intrinsics::discriminant_value(&vec![1, 2, 3]);
+}
diff --git a/src/tools/miri/tests/pass/ints.rs b/src/tools/miri/tests/pass/ints.rs
new file mode 100644
index 000000000000..c04c6921f3c4
--- /dev/null
+++ b/src/tools/miri/tests/pass/ints.rs
@@ -0,0 +1,58 @@
+fn ret() -> i64 {
+    1
+}
+
+fn neg() -> i64 {
+    -1
+}
+
+fn add() -> i64 {
+    1 + 2
+}
+
+fn indirect_add() -> i64 {
+    let x = 1;
+    let y = 2;
+    x + y
+}
+
+fn arith() -> i32 {
+    3 * 3 + 4 * 4
+}
+
+fn match_int() -> i16 {
+    let n = 2;
+    match n {
+        0 => 0,
+        1 => 10,
+        2 => 20,
+        3 => 30,
+        _ => 100,
+    }
+}
+
+fn match_int_range() -> i64 {
+    let n = 42;
+    match n {
+        0..=9 => 0,
+        10..=19 => 1,
+        20..=29 => 2,
+        30..=39 => 3,
+        40..=42 => 4,
+        _ => 5,
+    }
+}
+
+fn main() {
+    assert_eq!(ret(), 1);
+    assert_eq!(neg(), -1);
+    assert_eq!(add(), 3);
+    assert_eq!(indirect_add(), 3);
+    assert_eq!(arith(), 5 * 5);
+    assert_eq!(match_int(), 20);
+    assert_eq!(match_int_range(), 4);
+    assert_eq!(i64::MIN.overflowing_mul(-1), (i64::MIN, true));
+    assert_eq!(i32::MIN.overflowing_mul(-1), (i32::MIN, true));
+    assert_eq!(i16::MIN.overflowing_mul(-1), (i16::MIN, true));
+    assert_eq!(i8::MIN.overflowing_mul(-1), (i8::MIN, true));
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-15063.rs b/src/tools/miri/tests/pass/issues/issue-15063.rs
new file mode 100644
index 000000000000..cbb1b90f6862
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-15063.rs
@@ -0,0 +1,11 @@
+#[allow(dead_code)]
+enum Two {
+    A,
+    B,
+}
+impl Drop for Two {
+    fn drop(&mut self) {}
+}
+fn main() {
+    let _k = Two::A;
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-15080.rs b/src/tools/miri/tests/pass/issues/issue-15080.rs
new file mode 100644
index 000000000000..4a360993116c
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-15080.rs
@@ -0,0 +1,19 @@
+fn main() {
+    let mut x: &[_] = &[1, 2, 3, 4];
+
+    let mut result = vec![];
+    loop {
+        x = match *x {
+            [1, n, 3, ref rest @ ..] => {
+                result.push(n);
+                rest
+            }
+            [n, ref rest @ ..] => {
+                result.push(n);
+                rest
+            }
+            [] => break,
+        }
+    }
+    assert_eq!(result, [2, 4]);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-15523-big.rs b/src/tools/miri/tests/pass/issues/issue-15523-big.rs
new file mode 100644
index 000000000000..7c9fec3ab04b
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-15523-big.rs
@@ -0,0 +1,37 @@
+// Issue 15523: derive(PartialOrd) should use the provided
+// discriminant values for the derived ordering.
+//
+// This test is checking corner cases that arise when you have
+// 64-bit values in the variants.
+
+#[derive(PartialEq, PartialOrd)]
+#[repr(u64)]
+enum Eu64 {
+    Pos2 = 2,
+    PosMax = !0,
+    Pos1 = 1,
+}
+
+#[derive(PartialEq, PartialOrd)]
+#[repr(i64)]
+enum Ei64 {
+    Pos2 = 2,
+    Neg1 = -1,
+    NegMin = 1 << 63,
+    PosMax = !(1 << 63),
+    Pos1 = 1,
+}
+
+fn main() {
+    assert!(Eu64::Pos2 > Eu64::Pos1);
+    assert!(Eu64::Pos2 < Eu64::PosMax);
+    assert!(Eu64::Pos1 < Eu64::PosMax);
+
+    assert!(Ei64::Pos2 > Ei64::Pos1);
+    assert!(Ei64::Pos2 > Ei64::Neg1);
+    assert!(Ei64::Pos1 > Ei64::Neg1);
+    assert!(Ei64::Pos2 > Ei64::NegMin);
+    assert!(Ei64::Pos1 > Ei64::NegMin);
+    assert!(Ei64::Pos2 < Ei64::PosMax);
+    assert!(Ei64::Pos1 < Ei64::PosMax);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-17877.rs b/src/tools/miri/tests/pass/issues/issue-17877.rs
new file mode 100644
index 000000000000..64d397f91aee
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-17877.rs
@@ -0,0 +1,17 @@
+fn main() {
+    assert_eq!(
+        match [0u8; 16 * 1024] {
+            _ => 42_usize,
+        },
+        42_usize,
+    );
+
+    assert_eq!(
+        match [0u8; 16 * 1024] {
+            [1, ..] => 0_usize,
+            [0, ..] => 1_usize,
+            _ => 2_usize,
+        },
+        1_usize,
+    );
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-20575.rs b/src/tools/miri/tests/pass/issues/issue-20575.rs
new file mode 100644
index 000000000000..19049b9add5c
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-20575.rs
@@ -0,0 +1,7 @@
+// Test that overloaded calls work with zero arity closures
+
+fn main() {
+    let functions: [Box<dyn Fn() -> Option<()>>; 1] = [Box::new(|| None)];
+
+    let _val: Option<Vec<()>> = functions.iter().map(|f| (*f)()).collect();
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-23261.rs b/src/tools/miri/tests/pass/issues/issue-23261.rs
new file mode 100644
index 000000000000..f98252c18bf5
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-23261.rs
@@ -0,0 +1,60 @@
+// Matching on a DST struct should not trigger an LLVM assertion.
+
+struct Foo<T: ?Sized> {
+    a: i32,
+    inner: T,
+}
+
+trait Get {
+    fn get(&self) -> i32;
+}
+
+impl Get for i32 {
+    fn get(&self) -> i32 {
+        *self
+    }
+}
+
+fn check_val(val: &Foo<[u8]>) {
+    match *val {
+        Foo { a, .. } => {
+            assert_eq!(a, 32);
+        }
+    }
+}
+
+fn check_dst_val(val: &Foo<[u8]>) {
+    match *val {
+        Foo { ref inner, .. } => {
+            assert_eq!(inner, [1, 2, 3]);
+        }
+    }
+}
+
+fn check_both(val: &Foo<[u8]>) {
+    match *val {
+        Foo { a, ref inner } => {
+            assert_eq!(a, 32);
+            assert_eq!(inner, [1, 2, 3]);
+        }
+    }
+}
+
+fn check_trait_obj(val: &Foo<dyn Get>) {
+    match *val {
+        Foo { a, ref inner } => {
+            assert_eq!(a, 32);
+            assert_eq!(inner.get(), 32);
+        }
+    }
+}
+
+fn main() {
+    let foo: &Foo<[u8]> = &Foo { a: 32, inner: [1, 2, 3] };
+    check_val(foo);
+    check_dst_val(foo);
+    check_both(foo);
+
+    let foo: &Foo<dyn Get> = &Foo { a: 32, inner: 32 };
+    check_trait_obj(foo);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-26709.rs b/src/tools/miri/tests/pass/issues/issue-26709.rs
new file mode 100644
index 000000000000..78f30e78db76
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-26709.rs
@@ -0,0 +1,16 @@
+struct Wrapper<'a, T: ?Sized>(&'a mut i32, T);
+
+impl<'a, T: ?Sized> Drop for Wrapper<'a, T> {
+    fn drop(&mut self) {
+        *self.0 = 432;
+    }
+}
+
+fn main() {
+    let mut x = 0;
+    {
+        let wrapper = Box::new(Wrapper(&mut x, 123));
+        let _val: Box<Wrapper<dyn Send>> = wrapper;
+    }
+    assert_eq!(432, x)
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-27901.rs b/src/tools/miri/tests/pass/issues/issue-27901.rs
new file mode 100644
index 000000000000..a9f5dc98720f
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-27901.rs
@@ -0,0 +1,14 @@
+trait Stream {
+    type Item;
+}
+impl<'a> Stream for &'a str {
+    type Item = u8;
+}
+fn f<'s>(s: &'s str) -> (&'s str, <&'s str as Stream>::Item) {
+    (s, 42)
+}
+
+fn main() {
+    let fx = f as for<'t> fn(&'t str) -> (&'t str, <&'t str as Stream>::Item);
+    assert_eq!(fx("hi"), ("hi", 42));
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-29746.rs b/src/tools/miri/tests/pass/issues/issue-29746.rs
new file mode 100644
index 000000000000..43bed4464b9c
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-29746.rs
@@ -0,0 +1,35 @@
+// zip!(a1,a2,a3,a4) is equivalent to:
+//  a1.zip(a2).zip(a3).zip(a4).map(|(((x1,x2),x3),x4)| (x1,x2,x3,x4))
+macro_rules! zip {
+    // Entry point
+    ([$a:expr, $b:expr, $($rest:expr),*]) => {
+        zip!([$($rest),*], $a.zip($b), (x,y), [x,y])
+    };
+
+    // Intermediate steps to build the zipped expression, the match pattern, and
+    //  and the output tuple of the closure, using macro hygene to repeatedly
+    //  introduce new variables named 'x'.
+    ([$a:expr, $($rest:expr),*], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+        zip!([$($rest),*], $zip.zip($a), ($pat,x), [$($flat),*, x])
+    };
+
+    // Final step
+    ([], $zip:expr, $pat:pat, [$($flat:expr),+]) => {
+        $zip.map(|$pat| ($($flat),+))
+    };
+
+    // Comma
+    ([$a:expr], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+        zip!([$a,], $zip, $pat, [$($flat),*])
+    };
+}
+
+fn main() {
+    let p1 = vec![1i32, 2].into_iter();
+    let p2 = vec!["10", "20"].into_iter();
+    let p3 = vec![100u16, 200].into_iter();
+    let p4 = vec![1000i64, 2000].into_iter();
+
+    let e = zip!([p1, p2, p3, p4]).collect::<Vec<_>>();
+    assert_eq!(e[0], (1i32, "10", 100u16, 1000i64));
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-30530.rs b/src/tools/miri/tests/pass/issues/issue-30530.rs
new file mode 100644
index 000000000000..472b42adaac8
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-30530.rs
@@ -0,0 +1,38 @@
+// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for Issue #30530: alloca's created for storing
+// intermediate scratch values during brace-less match arms need to be
+// initialized with their drop-flag set to "dropped" (or else we end
+// up running the destructors on garbage data at the end of the
+// function).
+
+pub enum Handler {
+    Default,
+    #[allow(dead_code)]
+    Custom(*mut Box<dyn Fn()>),
+}
+
+fn main() {
+    #[allow(unused_must_use)]
+    {
+        take(Handler::Default, Box::new(main));
+    }
+}
+
+#[inline(never)]
+pub fn take(h: Handler, f: Box<dyn Fn()>) -> Box<dyn Fn()> {
+    unsafe {
+        match h {
+            Handler::Custom(ptr) => *Box::from_raw(ptr),
+            Handler::Default => f,
+        }
+    }
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-31267-additional.rs b/src/tools/miri/tests/pass/issues/issue-31267-additional.rs
new file mode 100644
index 000000000000..f6d7209369b7
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-31267-additional.rs
@@ -0,0 +1,17 @@
+#[derive(Clone, Copy, Debug)]
+struct Bar;
+
+const BAZ: Bar = Bar;
+
+#[derive(Debug)]
+struct Foo([Bar; 1]);
+
+struct Biz;
+
+impl Biz {
+    const BAZ: Foo = Foo([BAZ; 1]);
+}
+
+fn main() {
+    let _foo = Biz::BAZ;
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-33387.rs b/src/tools/miri/tests/pass/issues/issue-33387.rs
new file mode 100644
index 000000000000..36b58c642d7d
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-33387.rs
@@ -0,0 +1,9 @@
+use std::sync::Arc;
+
+trait Foo {}
+
+impl Foo for [u8; 2] {}
+
+fn main() {
+    let _val: Arc<dyn Foo + Send> = Arc::new([3, 4]);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-34571.rs b/src/tools/miri/tests/pass/issues/issue-34571.rs
new file mode 100644
index 000000000000..e1ed8d19e4ea
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-34571.rs
@@ -0,0 +1,10 @@
+#[repr(u8)]
+enum Foo {
+    Foo(u8),
+}
+
+fn main() {
+    match Foo::Foo(1) {
+        _ => (),
+    }
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-35815.rs b/src/tools/miri/tests/pass/issues/issue-35815.rs
new file mode 100644
index 000000000000..62b3220967ed
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-35815.rs
@@ -0,0 +1,14 @@
+use std::mem;
+
+#[allow(dead_code)]
+struct Foo<T: ?Sized> {
+    a: i64,
+    b: bool,
+    c: T,
+}
+
+fn main() {
+    let foo: &Foo<i32> = &Foo { a: 1, b: false, c: 2i32 };
+    let foo_unsized: &Foo<dyn Send> = foo;
+    assert_eq!(mem::size_of_val(foo), mem::size_of_val(foo_unsized));
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-36278-prefix-nesting.rs b/src/tools/miri/tests/pass/issues/issue-36278-prefix-nesting.rs
new file mode 100644
index 000000000000..6bc8f02c3baf
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-36278-prefix-nesting.rs
@@ -0,0 +1,22 @@
+// Issue 36278: On an unsized struct with >1 level of nontrivial
+// nesting, ensure we are computing dynamic size of prefix correctly.
+
+use std::mem;
+
+const SZ: usize = 100;
+struct P<T: ?Sized>([u8; SZ], T);
+
+type Ack<T> = P<P<T>>;
+
+fn main() {
+    let size_of_sized;
+    let size_of_unsized;
+    let x: Box<Ack<[u8; 0]>> = Box::new(P([0; SZ], P([0; SZ], [0; 0])));
+    size_of_sized = mem::size_of_val::<Ack<_>>(&x);
+    let align_of_sized = mem::align_of_val::<Ack<_>>(&x);
+    let y: Box<Ack<[u8]>> = x;
+    size_of_unsized = mem::size_of_val::<Ack<_>>(&y);
+    assert_eq!(size_of_sized, size_of_unsized);
+    assert_eq!(align_of_sized, 1);
+    assert_eq!(mem::align_of_val::<Ack<_>>(&y), 1);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-3794.rs b/src/tools/miri/tests/pass/issues/issue-3794.rs
new file mode 100644
index 000000000000..5b5b22b54948
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-3794.rs
@@ -0,0 +1,32 @@
+#![feature(box_syntax)]
+
+trait T {
+    fn print(&self);
+}
+
+#[derive(Debug)]
+struct S {
+    #[allow(dead_code)]
+    s: isize,
+}
+
+impl T for S {
+    fn print(&self) {
+        println!("{:?}", self);
+    }
+}
+
+fn print_t(t: &dyn T) {
+    t.print();
+}
+
+fn print_s(s: &S) {
+    s.print();
+}
+
+pub fn main() {
+    let s: Box<S> = box S { s: 5 };
+    print_s(&*s);
+    let t: Box<dyn T> = s as Box<dyn T>;
+    print_t(&*t);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-3794.stdout b/src/tools/miri/tests/pass/issues/issue-3794.stdout
new file mode 100644
index 000000000000..e4afe6fa55f1
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-3794.stdout
@@ -0,0 +1,2 @@
+S { s: 5 }
+S { s: 5 }
diff --git a/src/tools/miri/tests/pass/issues/issue-53728.rs b/src/tools/miri/tests/pass/issues/issue-53728.rs
new file mode 100644
index 000000000000..0c858d3444fb
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-53728.rs
@@ -0,0 +1,18 @@
+#[repr(u16)]
+#[allow(dead_code)]
+enum DeviceKind {
+    Nil = 0,
+}
+
+#[repr(packed)]
+#[allow(dead_code)]
+struct DeviceInfo {
+    endianness: u8,
+    device_kind: DeviceKind,
+}
+
+fn main() {
+    let _x = None::<(DeviceInfo, u8)>;
+    let _y = None::<(DeviceInfo, u16)>;
+    let _z = None::<(DeviceInfo, u64)>;
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-5917.rs b/src/tools/miri/tests/pass/issues/issue-5917.rs
new file mode 100644
index 000000000000..f7bbb4350e2b
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-5917.rs
@@ -0,0 +1,6 @@
+struct T(&'static [isize]);
+static STATIC: T = T(&[5, 4, 3]);
+pub fn main() {
+    let T(ref v) = STATIC;
+    assert_eq!(v[0], 5);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-73223.rs b/src/tools/miri/tests/pass/issues/issue-73223.rs
new file mode 100644
index 000000000000..df13787aad69
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-73223.rs
@@ -0,0 +1,23 @@
+fn main() {
+    let mut state = State { prev: None, next: Some(8) };
+    let path = "/nested/some/more";
+    assert_eq!(state.rest(path), "some/more");
+}
+
+#[allow(unused)]
+struct State {
+    prev: Option<usize>,
+    next: Option<usize>,
+}
+
+impl State {
+    fn rest<'r>(&mut self, path: &'r str) -> &'r str {
+        let start = match self.next.take() {
+            Some(v) => v,
+            None => return "",
+        };
+
+        self.prev = Some(start);
+        &path[start..]
+    }
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-91636.rs b/src/tools/miri/tests/pass/issues/issue-91636.rs
new file mode 100644
index 000000000000..21000bb68d2b
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-91636.rs
@@ -0,0 +1,20 @@
+type BuiltIn = for<'a> fn(&str);
+
+struct Function {
+    inner: BuiltIn,
+}
+
+impl Function {
+    fn new(subr: BuiltIn) -> Self {
+        Self { inner: subr }
+    }
+}
+
+fn dummy(_: &str) {}
+
+fn main() {
+    let func1 = Function::new(dummy);
+    let func2 = Function::new(dummy);
+    let inner: fn(&'static _) -> _ = func1.inner;
+    assert!(inner == func2.inner);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-94371.rs b/src/tools/miri/tests/pass/issues/issue-94371.rs
new file mode 100644
index 000000000000..1336348efb17
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-94371.rs
@@ -0,0 +1,13 @@
+#[repr(C)]
+struct Demo(u64, bool, u64, u32, u64, u64, u64);
+
+fn test() -> (Demo, Demo) {
+    let mut x = Demo(1, true, 3, 4, 5, 6, 7);
+    let mut y = Demo(10, false, 12, 13, 14, 15, 16);
+    std::mem::swap(&mut x, &mut y);
+    (x, y)
+}
+
+fn main() {
+    drop(test());
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-1075.rs b/src/tools/miri/tests/pass/issues/issue-miri-1075.rs
new file mode 100644
index 000000000000..8bacaca9c2ac
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-1075.rs
@@ -0,0 +1,6 @@
+fn main() {
+    let f: fn() -> ! = || std::process::exit(0);
+    f();
+
+    // FIXME: Also add a test for <https://github.com/rust-lang/rust/issues/66738>, once that is fixed.
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-133.rs b/src/tools/miri/tests/pass/issues/issue-miri-133.rs
new file mode 100644
index 000000000000..02c973257133
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-133.rs
@@ -0,0 +1,25 @@
+use std::mem::size_of;
+
+struct S<U, V> {
+    _u: U,
+    size_of_u: usize,
+    _v: V,
+    size_of_v: usize,
+}
+
+impl<U, V> S<U, V> {
+    fn new(u: U, v: V) -> Self {
+        S { _u: u, size_of_u: size_of::<U>(), _v: v, size_of_v: size_of::<V>() }
+    }
+}
+
+impl<V, U> Drop for S<U, V> {
+    fn drop(&mut self) {
+        assert_eq!(size_of::<U>(), self.size_of_u);
+        assert_eq!(size_of::<V>(), self.size_of_v);
+    }
+}
+
+fn main() {
+    S::new(0u8, 1u16);
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-184.rs b/src/tools/miri/tests/pass/issues/issue-miri-184.rs
new file mode 100644
index 000000000000..39c841403ef0
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-184.rs
@@ -0,0 +1,4 @@
+pub fn main() {
+    let bytes: [u8; 8] = unsafe { ::std::mem::transmute(0u64) };
+    let _val: &[u8] = &bytes;
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-1925.rs b/src/tools/miri/tests/pass/issues/issue-miri-1925.rs
new file mode 100644
index 000000000000..865568134919
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-1925.rs
@@ -0,0 +1,33 @@
+//@compile-flags: -Zmiri-symbolic-alignment-check
+
+use std::mem::size_of;
+
+fn main() {
+    let mut a = Params::new();
+    a.key_block = [0; BLOCKBYTES];
+}
+
+#[repr(C)]
+#[derive(Clone)]
+#[allow(unused)]
+pub struct Params {
+    hash_length: u8,
+    key_length: u8,
+    key_block: [u8; BLOCKBYTES],
+    max_leaf_length: u32,
+}
+
+pub const OUTBYTES: usize = 8 * size_of::<u64>();
+pub const KEYBYTES: usize = 8 * size_of::<u64>();
+pub const BLOCKBYTES: usize = 16 * size_of::<u64>();
+
+impl Params {
+    pub fn new() -> Self {
+        Self {
+            hash_length: OUTBYTES as u8,
+            key_length: 0,
+            key_block: [0; BLOCKBYTES],
+            max_leaf_length: 0,
+        }
+    }
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-2068.rs b/src/tools/miri/tests/pass/issues/issue-miri-2068.rs
new file mode 100644
index 000000000000..7576ba78f607
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-2068.rs
@@ -0,0 +1,48 @@
+#![feature(pin_macro)]
+
+use core::future::Future;
+use core::pin::Pin;
+use core::task::{Context, Poll};
+
+use std::sync::Arc;
+
+struct NopWaker;
+
+impl std::task::Wake for NopWaker {
+    fn wake(self: Arc<Self>) {}
+}
+
+pub fn fuzzing_block_on<O, F: Future<Output = O>>(fut: F) -> O {
+    let mut fut = std::pin::pin!(fut);
+    let waker = std::task::Waker::from(Arc::new(NopWaker));
+    let mut context = std::task::Context::from_waker(&waker);
+    loop {
+        match fut.as_mut().poll(&mut context) {
+            Poll::Ready(v) => return v,
+            Poll::Pending => {}
+        }
+    }
+}
+
+pub struct LastFuture<S> {
+    last: S,
+}
+
+impl<S> Future for LastFuture<S>
+where
+    Self: Unpin,
+    S: Unpin + Copy,
+{
+    type Output = S;
+
+    fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
+        return Poll::Ready(self.last);
+    }
+}
+
+fn main() {
+    fuzzing_block_on(async {
+        LastFuture { last: &0u32 }.await;
+        LastFuture { last: Option::<u32>::None }.await;
+    });
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-2123.rs b/src/tools/miri/tests/pass/issues/issue-miri-2123.rs
new file mode 100644
index 000000000000..e39e5fe454a2
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-2123.rs
@@ -0,0 +1,21 @@
+#![feature(ptr_metadata, layout_for_ptr)]
+
+use std::{mem, ptr};
+
+trait Foo {}
+
+impl Foo for u32 {}
+
+fn uwu(thin: *const (), meta: &'static ()) -> *const dyn Foo {
+    ptr::from_raw_parts(thin, unsafe { mem::transmute(meta) })
+}
+
+fn main() {
+    unsafe {
+        let orig = 1_u32;
+        let x = &orig as &dyn Foo;
+        let (ptr, meta) = (x as *const dyn Foo).to_raw_parts();
+        let ptr = uwu(ptr, mem::transmute(meta));
+        let _size = mem::size_of_val_raw(ptr);
+    }
+}
diff --git a/src/tools/miri/tests/pass/issues/issue-miri-2433.rs b/src/tools/miri/tests/pass/issues/issue-miri-2433.rs
new file mode 100644
index 000000000000..de719df0f1f3
--- /dev/null
+++ b/src/tools/miri/tests/pass/issues/issue-miri-2433.rs
@@ -0,0 +1,22 @@
+#![feature(type_alias_impl_trait)]
+
+trait T { type Item; }
+
+type Alias<'a> = impl T<Item = &'a ()>;
+
+struct S;
+impl<'a> T for &'a S {
+    type Item = &'a ();
+}
+
+fn filter_positive<'a>() -> Alias<'a> {
+    &S
+}
+
+fn with_positive(fun: impl Fn(Alias<'_>)) {
+    fun(filter_positive());
+}
+
+fn main() {
+    with_positive(|_| ());
+}
diff --git a/src/tools/miri/tests/pass/iter.rs b/src/tools/miri/tests/pass/iter.rs
new file mode 100644
index 000000000000..31d0d7442d9d
--- /dev/null
+++ b/src/tools/miri/tests/pass/iter.rs
@@ -0,0 +1,41 @@
+fn iter_empty_and_zst() {
+    // Iterate over a Unique::empty()
+    for _ in Vec::<u32>::new().iter() {
+        panic!("We should never be here.");
+    }
+
+    // Iterate over a ZST (uses arith_offset internally)
+    let mut count = 0;
+    for _ in &[(), (), ()] {
+        count += 1;
+    }
+    assert_eq!(count, 3);
+}
+
+fn test_iterator_step_by_nth() {
+    let mut it = (0..16).step_by(5);
+    assert_eq!(it.nth(0), Some(0));
+    assert_eq!(it.nth(0), Some(5));
+    assert_eq!(it.nth(0), Some(10));
+    assert_eq!(it.nth(0), Some(15));
+    assert_eq!(it.nth(0), None);
+}
+
+fn iter_any() {
+    let f = |x: &u8| 10u8 == *x;
+    f(&1u8);
+
+    let g = |(), x: &u8| 10u8 == *x;
+    g((), &1u8);
+
+    let h = |(), (), x: &u8| 10u8 == *x;
+    h((), (), &1u8);
+
+    [1, 2, 3u8].iter().any(|elt| 10 == *elt);
+}
+
+fn main() {
+    test_iterator_step_by_nth();
+    iter_any();
+    iter_empty_and_zst();
+}
diff --git a/src/tools/miri/tests/pass/last-use-in-cap-clause.rs b/src/tools/miri/tests/pass/last-use-in-cap-clause.rs
new file mode 100644
index 000000000000..2160aea16346
--- /dev/null
+++ b/src/tools/miri/tests/pass/last-use-in-cap-clause.rs
@@ -0,0 +1,17 @@
+// Make sure #1399 stays fixed
+
+#[allow(dead_code)]
+struct A {
+    a: Box<isize>,
+}
+
+fn foo() -> Box<dyn FnMut() -> isize + 'static> {
+    let k: Box<_> = Box::new(22);
+    let _u = A { a: k.clone() };
+    let result = || 22;
+    Box::new(result)
+}
+
+pub fn main() {
+    assert_eq!(foo()(), 22);
+}
diff --git a/src/tools/miri/tests/pass/leak-in-static.rs b/src/tools/miri/tests/pass/leak-in-static.rs
new file mode 100644
index 000000000000..952339440880
--- /dev/null
+++ b/src/tools/miri/tests/pass/leak-in-static.rs
@@ -0,0 +1,23 @@
+use std::{
+    ptr,
+    sync::atomic::{AtomicPtr, Ordering},
+};
+
+static mut LEAKER: Option<Box<Vec<i32>>> = None;
+
+fn main() {
+    // Having memory "leaked" in globals is allowed.
+    unsafe {
+        LEAKER = Some(Box::new(vec![0; 42]));
+    }
+
+    // Make sure this is allowed even when `AtomicPtr` is used.
+    {
+        static LEAK: AtomicPtr<usize> = AtomicPtr::new(ptr::null_mut());
+        LEAK.store(Box::into_raw(Box::new(0usize)), Ordering::SeqCst);
+
+        static LEAK2: AtomicPtr<usize> = AtomicPtr::new(ptr::null_mut());
+        // Make sure this also works when using 'swap'.
+        LEAK2.swap(Box::into_raw(Box::new(0usize)), Ordering::SeqCst);
+    }
+}
diff --git a/src/tools/miri/tests/pass/linked-list.rs b/src/tools/miri/tests/pass/linked-list.rs
new file mode 100644
index 000000000000..7377f9f60b01
--- /dev/null
+++ b/src/tools/miri/tests/pass/linked-list.rs
@@ -0,0 +1,51 @@
+#![feature(linked_list_cursors)]
+use std::collections::LinkedList;
+
+fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> {
+    v.iter().cloned().collect()
+}
+
+// Gather all references from a mutable iterator and make sure Miri notices if
+// using them is dangerous.
+fn test_all_refs<'a, T: 'a>(dummy: &mut T, iter: impl Iterator<Item = &'a mut T>) {
+    // Gather all those references.
+    let mut refs: Vec<&mut T> = iter.collect();
+    // Use them all. Twice, to be sure we got all interleavings.
+    for r in refs.iter_mut() {
+        std::mem::swap(dummy, r);
+    }
+    for r in refs {
+        std::mem::swap(dummy, r);
+    }
+}
+
+fn main() {
+    let mut m = list_from(&[0, 2, 4, 6, 8]);
+    let len = m.len();
+    {
+        let mut it = m.cursor_front_mut();
+        it.insert_before(-2);
+        loop {
+            match it.current().copied() {
+                None => break,
+                Some(elt) => {
+                    match it.peek_next() {
+                        Some(x) => assert_eq!(*x, elt + 2),
+                        None => assert_eq!(8, elt),
+                    }
+                    it.insert_after(elt + 1);
+                    it.move_next(); // Move by 2 to skip the one we inserted.
+                    it.move_next();
+                }
+            }
+        }
+        it.insert_before(99);
+        it.insert_after(-10);
+    }
+
+    assert_eq!(m.len(), 3 + len * 2);
+    let mut m2 = m.clone();
+    assert_eq!(m.into_iter().collect::<Vec<_>>(), [-10, -2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 99]);
+
+    test_all_refs(&mut 13, m2.iter_mut());
+}
diff --git a/src/tools/miri/tests/pass/loop-break-value.rs b/src/tools/miri/tests/pass/loop-break-value.rs
new file mode 100644
index 000000000000..bc4c967d26a5
--- /dev/null
+++ b/src/tools/miri/tests/pass/loop-break-value.rs
@@ -0,0 +1,125 @@
+#![feature(never_type)]
+#![allow(unreachable_code)]
+
+#[allow(unused)]
+fn never_returns() {
+    loop {
+        break loop {};
+    }
+}
+
+pub fn main() {
+    let value = 'outer: loop {
+        if 1 == 1 {
+            break 13;
+        } else {
+            let _never: ! = loop {
+                break loop {
+                    break 'outer panic!();
+                };
+            };
+        }
+    };
+    assert_eq!(value, 13);
+
+    let x = [1, 3u32, 5];
+    let y = [17];
+    let z = [];
+    let coerced: &[_] = loop {
+        match 2 {
+            1 => break &x,
+            2 => break &y,
+            3 => break &z,
+            _ => (),
+        }
+    };
+    assert_eq!(coerced, &[17u32]);
+
+    let trait_unified = loop {
+        break if true { break Default::default() } else { break [13, 14] };
+    };
+    assert_eq!(trait_unified, [0, 0]);
+
+    let trait_unified_2 = loop {
+        if false {
+            break [String::from("Hello")];
+        } else {
+            break Default::default();
+        };
+    };
+    // compare lengths; ptr comparison is not deterministic
+    assert_eq!(trait_unified_2.len(), 1);
+    assert_eq!(trait_unified_2[0].len(), 0);
+
+    let trait_unified_3 = loop {
+        break if false { break [String::from("Hello")] } else { ["Yes".into()] };
+    };
+    assert_eq!(trait_unified_3, ["Yes"]);
+
+    let regular_break = loop {
+        if true {
+            break;
+        } else {
+            break break Default::default();
+        }
+    };
+    assert_eq!(regular_break, ());
+
+    let regular_break_2 = loop {
+        if true {
+            break Default::default();
+        } else {
+            break;
+        }
+    };
+    assert_eq!(regular_break_2, ());
+
+    let regular_break_3 = loop {
+        break if true {
+            Default::default()
+        } else {
+            break;
+        };
+    };
+    assert_eq!(regular_break_3, ());
+
+    let regular_break_4 = loop {
+        break ();
+        break;
+    };
+    assert_eq!(regular_break_4, ());
+
+    let regular_break_5 = loop {
+        break;
+        break ();
+    };
+    assert_eq!(regular_break_5, ());
+
+    let nested_break_value = 'outer2: loop {
+        let _a: u32 = 'inner: loop {
+            if true {
+                break 'outer2 "hello";
+            } else {
+                break 'inner 17;
+            }
+        };
+        panic!();
+    };
+    assert_eq!(nested_break_value, "hello");
+
+    let break_from_while_cond = loop {
+        'inner_loop: while break 'inner_loop {
+            panic!();
+        }
+        break 123;
+    };
+    assert_eq!(break_from_while_cond, 123);
+
+    let break_from_while_to_outer = 'outer_loop: loop {
+        while break 'outer_loop 567 {
+            panic!("from_inner");
+        }
+        panic!("from outer");
+    };
+    assert_eq!(break_from_while_to_outer, 567);
+}
diff --git a/src/tools/miri/tests/pass/loops.rs b/src/tools/miri/tests/pass/loops.rs
new file mode 100644
index 000000000000..222287cbe09a
--- /dev/null
+++ b/src/tools/miri/tests/pass/loops.rs
@@ -0,0 +1,35 @@
+fn factorial_loop() -> i64 {
+    let mut product = 1;
+    let mut i = 1;
+
+    while i <= 10 {
+        product *= i;
+        i += 1;
+    }
+
+    product
+}
+
+fn index_for_loop() -> usize {
+    let mut sum = 0;
+    let a = [0, 10, 20, 30];
+    for i in 0..a.len() {
+        sum += a[i];
+    }
+    sum
+}
+
+fn for_loop() -> usize {
+    let mut sum = 0;
+    let a = [0, 10, 20, 30];
+    for &n in &a {
+        sum += n;
+    }
+    sum
+}
+
+fn main() {
+    assert_eq!(factorial_loop(), 3628800);
+    assert_eq!(index_for_loop(), 60);
+    assert_eq!(for_loop(), 60);
+}
diff --git a/src/tools/miri/tests/pass/main_fn.rs b/src/tools/miri/tests/pass/main_fn.rs
new file mode 100644
index 000000000000..3b84d1abe6f3
--- /dev/null
+++ b/src/tools/miri/tests/pass/main_fn.rs
@@ -0,0 +1,7 @@
+#![feature(imported_main)]
+
+mod foo {
+    pub(crate) fn bar() {}
+}
+
+use foo::bar as main;
diff --git a/src/tools/miri/tests/pass/main_result.rs b/src/tools/miri/tests/pass/main_result.rs
new file mode 100644
index 000000000000..078760ee6667
--- /dev/null
+++ b/src/tools/miri/tests/pass/main_result.rs
@@ -0,0 +1,3 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    Ok(())
+}
diff --git a/src/tools/miri/tests/pass/many_shr_bor.rs b/src/tools/miri/tests/pass/many_shr_bor.rs
new file mode 100644
index 000000000000..376b41dd6e20
--- /dev/null
+++ b/src/tools/miri/tests/pass/many_shr_bor.rs
@@ -0,0 +1,36 @@
+// Make sure validation can handle many overlapping shared borrows for different parts of a data structure
+use std::cell::RefCell;
+
+#[allow(unused)]
+struct Test {
+    a: u32,
+    b: u32,
+}
+
+fn test1() {
+    let t = &mut Test { a: 0, b: 0 };
+    {
+        let x;
+        {
+            let y = &t.a;
+            x = &t;
+            let _y = *y;
+        }
+        let _x = x.a;
+    }
+    t.b = 42;
+}
+
+fn test2(r: &mut RefCell<i32>) {
+    let x = &*r; // releasing write lock, first suspension recorded
+    let mut x_ref = x.borrow_mut();
+    let x_inner: &mut i32 = &mut *x_ref; // new inner write lock, with same lifetime as outer lock
+    let _x_inner_shr = &*x_inner; // releasing inner write lock, recording suspension
+    let _y = &*r; // second suspension for the outer write lock
+    let _x_inner_shr2 = &*x_inner; // 2nd suspension for inner write lock
+}
+
+fn main() {
+    test1();
+    test2(&mut RefCell::new(0));
+}
diff --git a/src/tools/miri/tests/pass/match_slice.rs b/src/tools/miri/tests/pass/match_slice.rs
new file mode 100644
index 000000000000..e40a63ef2003
--- /dev/null
+++ b/src/tools/miri/tests/pass/match_slice.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let x = "hello";
+    match x {
+        "foo" => {}
+        "bar" => {}
+        _ => {}
+    }
+}
diff --git a/src/tools/miri/tests/pass/memchr.rs b/src/tools/miri/tests/pass/memchr.rs
new file mode 100644
index 000000000000..e92c37ff2a8c
--- /dev/null
+++ b/src/tools/miri/tests/pass/memchr.rs
@@ -0,0 +1,89 @@
+#![feature(slice_internals)]
+
+use core::slice::memchr::{memchr, memrchr};
+
+// test fallback implementations on all targets
+fn matches_one() {
+    assert_eq!(Some(0), memchr(b'a', b"a"));
+}
+
+fn matches_begin() {
+    assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+}
+
+fn matches_end() {
+    assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+}
+
+fn matches_nul() {
+    assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+}
+
+fn matches_past_nul() {
+    assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+}
+
+fn no_match_empty() {
+    assert_eq!(None, memchr(b'a', b""));
+}
+
+fn no_match() {
+    assert_eq!(None, memchr(b'a', b"xyz"));
+}
+
+fn matches_one_reversed() {
+    assert_eq!(Some(0), memrchr(b'a', b"a"));
+}
+
+fn matches_begin_reversed() {
+    assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+}
+
+fn matches_end_reversed() {
+    assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+}
+
+fn matches_nul_reversed() {
+    assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+}
+
+fn matches_past_nul_reversed() {
+    assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+}
+
+fn no_match_empty_reversed() {
+    assert_eq!(None, memrchr(b'a', b""));
+}
+
+fn no_match_reversed() {
+    assert_eq!(None, memrchr(b'a', b"xyz"));
+}
+
+fn each_alignment_reversed() {
+    let mut data = [1u8; 64];
+    let needle = 2;
+    let pos = 40;
+    data[pos] = needle;
+    for start in 0..16 {
+        assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+    }
+}
+
+fn main() {
+    matches_one();
+    matches_begin();
+    matches_end();
+    matches_nul();
+    matches_past_nul();
+    no_match_empty();
+    no_match();
+
+    matches_one_reversed();
+    matches_begin_reversed();
+    matches_end_reversed();
+    matches_nul_reversed();
+    matches_past_nul_reversed();
+    no_match_empty_reversed();
+    no_match_reversed();
+    each_alignment_reversed();
+}
diff --git a/src/tools/miri/tests/pass/memleak_ignored.rs b/src/tools/miri/tests/pass/memleak_ignored.rs
new file mode 100644
index 000000000000..60e06094e177
--- /dev/null
+++ b/src/tools/miri/tests/pass/memleak_ignored.rs
@@ -0,0 +1,5 @@
+//@compile-flags: -Zmiri-ignore-leaks
+
+fn main() {
+    std::mem::forget(Box::new(42));
+}
diff --git a/src/tools/miri/tests/pass/move-arg-2-unique.rs b/src/tools/miri/tests/pass/move-arg-2-unique.rs
new file mode 100644
index 000000000000..669602ac7043
--- /dev/null
+++ b/src/tools/miri/tests/pass/move-arg-2-unique.rs
@@ -0,0 +1,11 @@
+#![feature(box_syntax)]
+
+fn test(foo: Box<Vec<isize>>) {
+    assert_eq!((*foo)[0], 10);
+}
+
+pub fn main() {
+    let x = box vec![10];
+    // Test forgetting a local by move-in
+    test(x);
+}
diff --git a/src/tools/miri/tests/pass/move-arg-3-unique.rs b/src/tools/miri/tests/pass/move-arg-3-unique.rs
new file mode 100644
index 000000000000..3b5c7cbbd42c
--- /dev/null
+++ b/src/tools/miri/tests/pass/move-arg-3-unique.rs
@@ -0,0 +1,7 @@
+#![feature(box_syntax)]
+
+pub fn main() {
+    let x = box 10;
+    let y = x;
+    assert_eq!(*y, 10);
+}
diff --git a/src/tools/miri/tests/pass/move-uninit-primval.rs b/src/tools/miri/tests/pass/move-uninit-primval.rs
new file mode 100644
index 000000000000..f5fd27fa0d4e
--- /dev/null
+++ b/src/tools/miri/tests/pass/move-uninit-primval.rs
@@ -0,0 +1,14 @@
+#![allow(deprecated)]
+
+use std::mem;
+
+struct Foo {
+    _inner: mem::MaybeUninit<i32>,
+}
+
+fn main() {
+    unsafe {
+        let foo = Foo { _inner: mem::uninitialized() };
+        let _bar = foo;
+    }
+}
diff --git a/src/tools/miri/tests/pass/mpsc.rs b/src/tools/miri/tests/pass/mpsc.rs
new file mode 100644
index 000000000000..6e3c6e771ccb
--- /dev/null
+++ b/src/tools/miri/tests/pass/mpsc.rs
@@ -0,0 +1,15 @@
+#![feature(box_syntax)]
+
+use std::sync::mpsc::channel;
+
+pub fn main() {
+    let (tx, rx) = channel::<Box<_>>();
+    tx.send(box 100).unwrap();
+    let v = rx.recv().unwrap();
+    assert_eq!(v, box 100);
+
+    tx.send(box 101).unwrap();
+    tx.send(box 102).unwrap();
+    assert_eq!(rx.recv().unwrap(), box 101);
+    assert_eq!(rx.recv().unwrap(), box 102);
+}
diff --git a/src/tools/miri/tests/pass/multi_arg_closure.rs b/src/tools/miri/tests/pass/multi_arg_closure.rs
new file mode 100644
index 000000000000..02d53540b83c
--- /dev/null
+++ b/src/tools/miri/tests/pass/multi_arg_closure.rs
@@ -0,0 +1,8 @@
+fn foo(f: &mut dyn FnMut(isize, isize) -> isize) -> isize {
+    f(1, 2)
+}
+
+fn main() {
+    let z = foo(&mut |x, y| x * 10 + y);
+    assert_eq!(z, 12);
+}
diff --git a/src/tools/miri/tests/pass/negative_discriminant.rs b/src/tools/miri/tests/pass/negative_discriminant.rs
new file mode 100644
index 000000000000..5a58deeac0f3
--- /dev/null
+++ b/src/tools/miri/tests/pass/negative_discriminant.rs
@@ -0,0 +1,16 @@
+enum AB {
+    A = -1,
+    B = 1,
+}
+
+fn main() {
+    match AB::A {
+        AB::A => (),
+        AB::B => panic!(),
+    }
+
+    match AB::B {
+        AB::A => panic!(),
+        AB::B => (),
+    }
+}
diff --git a/src/tools/miri/tests/pass/no_std.rs b/src/tools/miri/tests/pass/no_std.rs
new file mode 100644
index 000000000000..10632c2cce49
--- /dev/null
+++ b/src/tools/miri/tests/pass/no_std.rs
@@ -0,0 +1,21 @@
+#![feature(lang_items, start)]
+#![no_std]
+// windows tls dtors go through libstd right now, thus this test
+// cannot pass. When windows tls dtors go through the special magic
+// windows linker section, we can run this test on windows again.
+//@ignore-target-windows
+
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
+    for _ in 0..10 {}
+
+    0
+}
+
+#[panic_handler]
+fn panic_handler(_: &core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+#[lang = "eh_personality"]
+fn eh_personality() {}
diff --git a/src/tools/miri/tests/pass/observed_local_mut.rs b/src/tools/miri/tests/pass/observed_local_mut.rs
new file mode 100644
index 000000000000..ca0f569860b8
--- /dev/null
+++ b/src/tools/miri/tests/pass/observed_local_mut.rs
@@ -0,0 +1,24 @@
+// Stacked Borrows catches this (correctly) as UB.
+//@compile-flags: -Zmiri-disable-stacked-borrows
+
+// This test is intended to guard against the problem described in commit
+// 39bb1254d1eaf74f45a4e741097e33fc942168d5.
+//
+// As written, it might be considered UB in compiled Rust, but of course Miri gives it a safe,
+// deterministic behaviour (one that might not correspond with how an eventual Rust spec would
+// defined this).
+//
+// An alternative way to write the test without `unsafe` would be to use `Cell<i32>`, but it would
+// only surface the bug described by the above commit if `Cell<i32>` on the stack got represented
+// as a primitive `PrimVal::I32` which is not yet the case.
+
+fn main() {
+    let mut x = 0;
+    let y: *const i32 = &x;
+    x = 1;
+
+    // When the described bug is in place, this results in `0`, not observing the `x = 1` line.
+    assert_eq!(unsafe { *y }, 1);
+
+    assert_eq!(x, 1);
+}
diff --git a/src/tools/miri/tests/pass/option_box_transmute_ptr.rs b/src/tools/miri/tests/pass/option_box_transmute_ptr.rs
new file mode 100644
index 000000000000..0786db1ef895
--- /dev/null
+++ b/src/tools/miri/tests/pass/option_box_transmute_ptr.rs
@@ -0,0 +1,15 @@
+// This tests that the size of Option<Box<i32>> is the same as *const i32.
+fn option_box_deref() -> i32 {
+    let val = Some(Box::new(42));
+    unsafe {
+        let ptr: *const i32 = std::mem::transmute::<Option<Box<i32>>, *const i32>(val);
+        let ret = *ptr;
+        // unleak memory
+        std::mem::transmute::<*const i32, Option<Box<i32>>>(ptr);
+        ret
+    }
+}
+
+fn main() {
+    assert_eq!(option_box_deref(), 42);
+}
diff --git a/src/tools/miri/tests/pass/option_eq.rs b/src/tools/miri/tests/pass/option_eq.rs
new file mode 100644
index 000000000000..e698f8767746
--- /dev/null
+++ b/src/tools/miri/tests/pass/option_eq.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert_eq!(std::char::from_u32('x' as u32), Some('x'));
+}
diff --git a/src/tools/miri/tests/pass/overflow_checks_off.rs b/src/tools/miri/tests/pass/overflow_checks_off.rs
new file mode 100644
index 000000000000..79aa510ef97f
--- /dev/null
+++ b/src/tools/miri/tests/pass/overflow_checks_off.rs
@@ -0,0 +1,18 @@
+//@compile-flags: -C overflow-checks=off
+
+// Check that we correctly implement the intended behavior of these operators
+// when they are not being overflow-checked.
+
+// FIXME: if we call the functions in `std::ops`, we still get the panics.
+// Miri does not implement the codegen-time hack that backs `#[rustc_inherit_overflow_checks]`.
+// use std::ops::*;
+
+fn main() {
+    assert_eq!(-{ -0x80i8 }, -0x80);
+
+    assert_eq!(0xffu8 + 1, 0_u8);
+    assert_eq!(0u8 - 1, 0xff_u8);
+    assert_eq!(0xffu8 * 2, 0xfe_u8);
+    assert_eq!(1u8 << 9, 2_u8);
+    assert_eq!(2u8 >> 9, 1_u8);
+}
diff --git a/src/tools/miri/tests/pass/overloaded-calls-simple.rs b/src/tools/miri/tests/pass/overloaded-calls-simple.rs
new file mode 100644
index 000000000000..9fcf7d4a819a
--- /dev/null
+++ b/src/tools/miri/tests/pass/overloaded-calls-simple.rs
@@ -0,0 +1,19 @@
+#![feature(lang_items, unboxed_closures, fn_traits)]
+
+struct S3 {
+    x: i32,
+    y: i32,
+}
+
+impl FnOnce<(i32, i32)> for S3 {
+    type Output = i32;
+    extern "rust-call" fn call_once(self, (z, zz): (i32, i32)) -> i32 {
+        self.x * self.y * z * zz
+    }
+}
+
+fn main() {
+    let s = S3 { x: 3, y: 3 };
+    let ans = s(3, 1);
+    assert_eq!(ans, 27);
+}
diff --git a/src/tools/miri/tests/pass/packed_struct.rs b/src/tools/miri/tests/pass/packed_struct.rs
new file mode 100644
index 000000000000..85acab858aab
--- /dev/null
+++ b/src/tools/miri/tests/pass/packed_struct.rs
@@ -0,0 +1,151 @@
+#![feature(unsize, coerce_unsized)]
+
+use std::collections::hash_map::DefaultHasher;
+use std::hash::Hash;
+use std::ptr;
+
+fn test_basic() {
+    #[repr(packed)]
+    struct S {
+        fill: u8,
+        a: i32,
+        b: i64,
+    }
+
+    #[repr(packed)]
+    #[allow(dead_code)]
+    struct Test1<'a> {
+        x: u8,
+        other: &'a u32,
+    }
+
+    #[repr(packed)]
+    #[allow(dead_code)]
+    struct Test2<'a> {
+        x: u8,
+        other: &'a Test1<'a>,
+    }
+
+    fn test(t: Test2) {
+        let x = *t.other.other;
+        assert_eq!(x, 42);
+    }
+
+    let mut x = S { fill: 0, a: 42, b: 99 };
+    let a = x.a;
+    let b = x.b;
+    assert_eq!(a, 42);
+    assert_eq!(b, 99);
+    assert_eq!(&x.fill, &0); // `fill` just requirs 1-byte-align, so this is fine
+    // can't do `assert_eq!(x.a, 42)`, because `assert_eq!` takes a reference
+    assert_eq!({ x.a }, 42);
+    assert_eq!({ x.b }, 99);
+    // but we *can* take a raw pointer!
+    assert_eq!(unsafe { ptr::addr_of!(x.a).read_unaligned() }, 42);
+    assert_eq!(unsafe { ptr::addr_of!(x.b).read_unaligned() }, 99);
+
+    x.b = 77;
+    assert_eq!({ x.b }, 77);
+
+    test(Test2 { x: 0, other: &Test1 { x: 0, other: &42 } });
+}
+
+fn test_unsizing() {
+    #[repr(packed)]
+    #[allow(dead_code)]
+    struct UnalignedPtr<'a, T: ?Sized>
+    where
+        T: 'a,
+    {
+        data: &'a T,
+    }
+
+    impl<'a, T, U> std::ops::CoerceUnsized<UnalignedPtr<'a, U>> for UnalignedPtr<'a, T>
+    where
+        T: std::marker::Unsize<U> + ?Sized,
+        U: ?Sized,
+    {
+    }
+
+    let arr = [1, 2, 3];
+    let arr_unaligned: UnalignedPtr<[i32; 3]> = UnalignedPtr { data: &arr };
+    let arr_unaligned: UnalignedPtr<[i32]> = arr_unaligned;
+    let _unused = &arr_unaligned; // forcing an allocation, which could also yield "unaligned write"-errors
+}
+
+fn test_drop() {
+    struct Wrap(u32);
+    impl Drop for Wrap {
+        fn drop(&mut self) {
+            // Do an (aligned) load
+            let _test = self.0;
+            // For the fun of it, test alignment
+            assert_eq!(&self.0 as *const _ as usize % std::mem::align_of::<u32>(), 0);
+        }
+    }
+
+    #[repr(packed, C)]
+    struct Packed<T> {
+        f1: u8, // this should move the second field to something not very aligned
+        f2: T,
+    }
+
+    let p = Packed { f1: 42, f2: Wrap(23) };
+    drop(p);
+}
+
+fn test_inner_packed() {
+    // Even if just the inner struct is packed, accesses to the outer field can get unaligned.
+    // Make sure that works.
+    #[repr(packed)]
+    #[derive(Clone, Copy)]
+    struct Inner(u32);
+
+    #[derive(Clone, Copy)]
+    struct Outer(u8, Inner);
+
+    let o = Outer(0, Inner(42));
+    let _x = o.1;
+    let _y = (o.1).0;
+    let _o2 = o.clone();
+}
+
+fn test_static() {
+    #[repr(packed)]
+    struct Foo {
+        i: i32,
+    }
+
+    static FOO: Foo = Foo { i: 42 };
+
+    assert_eq!({ FOO.i }, 42);
+}
+
+fn test_derive() {
+    #[repr(packed)]
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default, Debug)]
+    struct P {
+        a: usize,
+        b: u8,
+        c: usize,
+    }
+
+    let x = P { a: 1usize, b: 2u8, c: 3usize };
+    let y = P { a: 1usize, b: 2u8, c: 4usize };
+
+    let _clone = x.clone();
+    assert!(x != y);
+    assert_eq!(x.partial_cmp(&y).unwrap(), x.cmp(&y));
+    x.hash(&mut DefaultHasher::new());
+    P::default();
+    format!("{:?}", x);
+}
+
+fn main() {
+    test_basic();
+    test_unsizing();
+    test_drop();
+    test_inner_packed();
+    test_static();
+    test_derive();
+}
diff --git a/src/tools/miri/tests/pass/panic/catch_panic.rs b/src/tools/miri/tests/pass/panic/catch_panic.rs
new file mode 100644
index 000000000000..308904406538
--- /dev/null
+++ b/src/tools/miri/tests/pass/panic/catch_panic.rs
@@ -0,0 +1,119 @@
+// We test the `align_offset` panic below, make sure we test the interpreter impl and not the "real" one.
+//@compile-flags: -Zmiri-symbolic-alignment-check -Zmiri-permissive-provenance
+#![feature(never_type)]
+#![allow(unconditional_panic, non_fmt_panics)]
+
+use std::cell::Cell;
+use std::panic::{catch_unwind, AssertUnwindSafe};
+
+thread_local! {
+    static MY_COUNTER: Cell<usize> = Cell::new(0);
+    static DROPPED: Cell<bool> = Cell::new(false);
+    static HOOK_CALLED: Cell<bool> = Cell::new(false);
+}
+
+struct DropTester;
+impl Drop for DropTester {
+    fn drop(&mut self) {
+        DROPPED.with(|c| {
+            c.set(true);
+        });
+    }
+}
+
+fn do_panic_counter(do_panic: impl FnOnce(usize) -> !) {
+    // If this gets leaked, it will be easy to spot
+    // in Miri's leak report
+    let _string = "LEAKED FROM do_panic_counter".to_string();
+
+    // When we panic, this should get dropped during unwinding
+    let _drop_tester = DropTester;
+
+    // Check for bugs in Miri's panic implementation.
+    // If do_panic_counter() somehow gets called more than once,
+    // we'll generate a different panic message and stderr will differ.
+    let old_val = MY_COUNTER.with(|c| {
+        let val = c.get();
+        c.set(val + 1);
+        val
+    });
+    do_panic(old_val);
+}
+
+fn main() {
+    let prev = std::panic::take_hook();
+    std::panic::set_hook(Box::new(move |panic_info| {
+        HOOK_CALLED.with(|h| h.set(true));
+        prev(panic_info)
+    }));
+
+    // Std panics
+    test(None, |_old_val| std::panic!("Hello from panic: std"));
+    test(None, |old_val| std::panic!(format!("Hello from panic: {:?}", old_val)));
+    test(None, |old_val| std::panic!("Hello from panic: {:?}", old_val));
+    test(None, |_old_val| std::panic!(1337));
+
+    // Core panics
+    test(None, |_old_val| core::panic!("Hello from panic: core"));
+    test(None, |old_val| core::panic!(&format!("Hello from panic: {:?}", old_val)));
+    test(None, |old_val| core::panic!("Hello from panic: {:?}", old_val));
+
+    // Built-in panics; also make sure the message is right.
+    test(Some("index out of bounds: the len is 3 but the index is 4"), |_old_val| {
+        let _val = [0, 1, 2][4];
+        loop {}
+    });
+    test(Some("attempt to divide by zero"), |_old_val| {
+        let _val = 1 / 0;
+        loop {}
+    });
+
+    test(Some("align_offset: align is not a power-of-two"), |_old_val| {
+        (0usize as *const u8).align_offset(3);
+        loop {}
+    });
+
+    // Assertion and debug assertion
+    test(None, |_old_val| {
+        assert!(false);
+        loop {}
+    });
+    test(None, |_old_val| {
+        debug_assert!(false);
+        loop {}
+    });
+
+    eprintln!("Success!"); // Make sure we get this in stderr
+}
+
+fn test(expect_msg: Option<&str>, do_panic: impl FnOnce(usize) -> !) {
+    // Reset test flags.
+    DROPPED.with(|c| c.set(false));
+    HOOK_CALLED.with(|c| c.set(false));
+
+    // Cause and catch a panic.
+    let res = catch_unwind(AssertUnwindSafe(|| {
+        let _string = "LEAKED FROM CLOSURE".to_string();
+        do_panic_counter(do_panic)
+    }))
+    .expect_err("do_panic() did not panic!");
+
+    // See if we can extract the panic message.
+    let msg = if let Some(s) = res.downcast_ref::<String>() {
+        eprintln!("Caught panic message (String): {}", s);
+        Some(s.as_str())
+    } else if let Some(s) = res.downcast_ref::<&str>() {
+        eprintln!("Caught panic message (&str): {}", s);
+        Some(*s)
+    } else {
+        eprintln!("Failed to get caught panic message.");
+        None
+    };
+    if let Some(expect_msg) = expect_msg {
+        assert_eq!(expect_msg, msg.unwrap());
+    }
+
+    // Test flags.
+    assert!(DROPPED.with(|c| c.get()));
+    assert!(HOOK_CALLED.with(|c| c.get()));
+}
diff --git a/src/tools/miri/tests/pass/panic/catch_panic.stderr b/src/tools/miri/tests/pass/panic/catch_panic.stderr
new file mode 100644
index 000000000000..0ced5588cc12
--- /dev/null
+++ b/src/tools/miri/tests/pass/panic/catch_panic.stderr
@@ -0,0 +1,26 @@
+thread 'main' panicked at 'Hello from panic: std', $DIR/catch_panic.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+Caught panic message (&str): Hello from panic: std
+thread 'main' panicked at 'Hello from panic: 1', $DIR/catch_panic.rs:LL:CC
+Caught panic message (String): Hello from panic: 1
+thread 'main' panicked at 'Hello from panic: 2', $DIR/catch_panic.rs:LL:CC
+Caught panic message (String): Hello from panic: 2
+thread 'main' panicked at 'Box<dyn Any>', $DIR/catch_panic.rs:LL:CC
+Failed to get caught panic message.
+thread 'main' panicked at 'Hello from panic: core', $DIR/catch_panic.rs:LL:CC
+Caught panic message (&str): Hello from panic: core
+thread 'main' panicked at 'Hello from panic: 5', $DIR/catch_panic.rs:LL:CC
+Caught panic message (String): Hello from panic: 5
+thread 'main' panicked at 'Hello from panic: 6', $DIR/catch_panic.rs:LL:CC
+Caught panic message (String): Hello from panic: 6
+thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 4', $DIR/catch_panic.rs:LL:CC
+Caught panic message (String): index out of bounds: the len is 3 but the index is 4
+thread 'main' panicked at 'attempt to divide by zero', $DIR/catch_panic.rs:LL:CC
+Caught panic message (&str): attempt to divide by zero
+thread 'main' panicked at 'align_offset: align is not a power-of-two', RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC
+Caught panic message (&str): align_offset: align is not a power-of-two
+thread 'main' panicked at 'assertion failed: false', $DIR/catch_panic.rs:LL:CC
+Caught panic message (&str): assertion failed: false
+thread 'main' panicked at 'assertion failed: false', $DIR/catch_panic.rs:LL:CC
+Caught panic message (&str): assertion failed: false
+Success!
diff --git a/src/tools/miri/tests/pass/panic/concurrent-panic.rs b/src/tools/miri/tests/pass/panic/concurrent-panic.rs
new file mode 100644
index 000000000000..342269c6acbe
--- /dev/null
+++ b/src/tools/miri/tests/pass/panic/concurrent-panic.rs
@@ -0,0 +1,93 @@
+//@ignore-target-windows: Condvars on Windows are not supported yet.
+// We are making scheduler assumptions here.
+//@compile-flags: -Zmiri-preemption-rate=0
+
+//! Cause a panic in one thread while another thread is unwinding. This checks
+//! that separate threads have their own panicking state.
+
+use std::sync::{Arc, Condvar, Mutex};
+use std::thread::{spawn, JoinHandle};
+
+struct BlockOnDrop(Option<JoinHandle<()>>);
+
+impl BlockOnDrop {
+    fn new(handle: JoinHandle<()>) -> BlockOnDrop {
+        BlockOnDrop(Some(handle))
+    }
+}
+
+impl Drop for BlockOnDrop {
+    fn drop(&mut self) {
+        eprintln!("Thread 2 blocking on thread 1");
+        let _ = self.0.take().unwrap().join();
+        eprintln!("Thread 1 has exited");
+    }
+}
+
+fn main() {
+    let t1_started_pair = Arc::new((Mutex::new(false), Condvar::new()));
+    let t2_started_pair = Arc::new((Mutex::new(false), Condvar::new()));
+
+    let t1_continue_mutex = Arc::new(Mutex::new(()));
+    let t1_continue_guard = t1_continue_mutex.lock();
+
+    let t1 = {
+        let t1_started_pair = t1_started_pair.clone();
+        let t1_continue_mutex = t1_continue_mutex.clone();
+        spawn(move || {
+            eprintln!("Thread 1 starting, will block on mutex");
+            let (mutex, condvar) = &*t1_started_pair;
+            *mutex.lock().unwrap() = true;
+            condvar.notify_one();
+
+            drop(t1_continue_mutex.lock());
+            panic!("panic in thread 1");
+        })
+    };
+
+    // Wait for thread 1 to signal it has started.
+    let (t1_started_mutex, t1_started_condvar) = &*t1_started_pair;
+    let mut t1_started_guard = t1_started_mutex.lock().unwrap();
+    while !*t1_started_guard {
+        t1_started_guard = t1_started_condvar.wait(t1_started_guard).unwrap();
+    }
+    eprintln!("Thread 1 reported it has started");
+    // Thread 1 should now be blocked waiting on t1_continue_mutex.
+
+    let t2 = {
+        let t2_started_pair = t2_started_pair.clone();
+        let block_on_drop = BlockOnDrop::new(t1);
+        spawn(move || {
+            let _ = block_on_drop;
+
+            let (mutex, condvar) = &*t2_started_pair;
+            *mutex.lock().unwrap() = true;
+            condvar.notify_one();
+
+            panic!("panic in thread 2");
+        })
+    };
+
+    // Wait for thread 2 to signal it has started.
+    let (t2_started_mutex, t2_started_condvar) = &*t2_started_pair;
+    let mut t2_started_guard = t2_started_mutex.lock().unwrap();
+    while !*t2_started_guard {
+        t2_started_guard = t2_started_condvar.wait(t2_started_guard).unwrap();
+    }
+    eprintln!("Thread 2 reported it has started");
+    // Thread 2 should now have already panicked and be in the middle of
+    // unwinding. It should now be blocked on joining thread 1.
+
+    // Unlock t1_continue_mutex, and allow thread 1 to proceed.
+    eprintln!("Unlocking mutex");
+    drop(t1_continue_guard);
+    // Thread 1 will panic the next time it is scheduled. This will test the
+    // behavior of interest to this test, whether Miri properly handles
+    // concurrent panics in two different threads.
+
+    // Block the main thread on waiting to join thread 2. Thread 2 should
+    // already be blocked on joining thread 1, so thread 1 will be scheduled
+    // to run next, as it is the only ready thread.
+    assert!(t2.join().is_err());
+    eprintln!("Thread 2 has exited");
+}
diff --git a/src/tools/miri/tests/pass/panic/concurrent-panic.stderr b/src/tools/miri/tests/pass/panic/concurrent-panic.stderr
new file mode 100644
index 000000000000..fd8fabc89ccc
--- /dev/null
+++ b/src/tools/miri/tests/pass/panic/concurrent-panic.stderr
@@ -0,0 +1,10 @@
+Thread 1 starting, will block on mutex
+Thread 1 reported it has started
+thread '<unnamed>' panicked at 'panic in thread 2', $DIR/concurrent-panic.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+Thread 2 blocking on thread 1
+Thread 2 reported it has started
+Unlocking mutex
+thread '<unnamed>' panicked at 'panic in thread 1', $DIR/concurrent-panic.rs:LL:CC
+Thread 1 has exited
+Thread 2 has exited
diff --git a/src/tools/miri/tests/pass/panic/std-panic-locations.rs b/src/tools/miri/tests/pass/panic/std-panic-locations.rs
new file mode 100644
index 000000000000..8781a371d51f
--- /dev/null
+++ b/src/tools/miri/tests/pass/panic/std-panic-locations.rs
@@ -0,0 +1,39 @@
+//! Test that panic locations for `#[track_caller]` functions in std have the correct
+//! location reported.
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+static HOOK_COUNT: AtomicUsize = AtomicUsize::new(0);
+
+fn main() {
+    // inspect the `PanicInfo` we receive to ensure the right file is the source
+    std::panic::set_hook(Box::new(|info| {
+        HOOK_COUNT.fetch_add(1, Ordering::Relaxed);
+        let actual = info.location().unwrap();
+        if actual.file() != file!() {
+            eprintln!("expected a location in the test file, found {:?}", actual);
+            panic!();
+        }
+    }));
+
+    fn assert_panicked(f: impl FnOnce() + std::panic::UnwindSafe) {
+        std::panic::catch_unwind(f).unwrap_err();
+    }
+
+    let nope: Option<()> = None;
+    assert_panicked(|| nope.unwrap());
+    assert_panicked(|| nope.expect(""));
+
+    let oops: Result<(), ()> = Err(());
+    assert_panicked(|| oops.unwrap());
+    assert_panicked(|| oops.expect(""));
+
+    let fine: Result<(), ()> = Ok(());
+    assert_panicked(|| fine.unwrap_err());
+    assert_panicked(|| fine.expect_err(""));
+
+    // Cleanup: reset to default hook.
+    drop(std::panic::take_hook());
+
+    assert_eq!(HOOK_COUNT.load(Ordering::Relaxed), 6);
+}
diff --git a/src/tools/miri/tests/pass/partially-uninit.rs b/src/tools/miri/tests/pass/partially-uninit.rs
new file mode 100644
index 000000000000..db26a2084b1c
--- /dev/null
+++ b/src/tools/miri/tests/pass/partially-uninit.rs
@@ -0,0 +1,15 @@
+use std::mem::{self, MaybeUninit};
+
+#[repr(C)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+struct Demo(bool, u16);
+
+fn main() {
+    unsafe {
+        // Transmute-round-trip through a type with Scalar layout is lossless.
+        // This is tricky because that 'scalar' is *partially* uninitialized.
+        let x = Demo(true, 3);
+        let y: MaybeUninit<u32> = mem::transmute(x);
+        assert_eq!(x, mem::transmute(y));
+    }
+}
diff --git a/src/tools/miri/tests/pass/pointers.rs b/src/tools/miri/tests/pass/pointers.rs
new file mode 100644
index 000000000000..d1340a04e049
--- /dev/null
+++ b/src/tools/miri/tests/pass/pointers.rs
@@ -0,0 +1,143 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(ptr_metadata, const_raw_ptr_comparison)]
+
+use std::mem::{self, transmute};
+use std::ptr;
+
+fn one_line_ref() -> i16 {
+    *&1
+}
+
+fn basic_ref() -> i16 {
+    let x = &1;
+    *x
+}
+
+fn basic_ref_mut() -> i16 {
+    let x = &mut 1;
+    *x += 2;
+    *x
+}
+
+fn basic_ref_mut_var() -> i16 {
+    let mut a = 1;
+    {
+        let x = &mut a;
+        *x += 2;
+    }
+    a
+}
+
+fn tuple_ref_mut() -> (i8, i8) {
+    let mut t = (10, 20);
+    {
+        let x = &mut t.1;
+        *x += 2;
+    }
+    t
+}
+
+fn match_ref_mut() -> i8 {
+    let mut t = (20, 22);
+    {
+        let opt = Some(&mut t);
+        match opt {
+            Some(&mut (ref mut x, ref mut y)) => *x += *y,
+            None => {}
+        }
+    }
+    t.0
+}
+
+fn dangling_pointer() -> *const i32 {
+    let b = Box::new((42, 42)); // make it bigger than the alignment, so that there is some "room" after this pointer
+    &b.0 as *const i32
+}
+
+fn wide_ptr_ops() {
+    let a: *const dyn Send = &1 as &dyn Send;
+    let b: *const dyn Send = &1 as &dyn Send;
+    let _val = a == b;
+    let _val = a != b;
+    let _val = a < b;
+    let _val = a <= b;
+    let _val = a > b;
+    let _val = a >= b;
+
+    let a: *const [u8] = unsafe { transmute((1usize, 1usize)) };
+    let b: *const [u8] = unsafe { transmute((1usize, 2usize)) };
+    // confirmed with rustc.
+    assert!(!(a == b));
+    assert!(a != b);
+    assert!(a <= b);
+    assert!(a < b);
+    assert!(!(a >= b));
+    assert!(!(a > b));
+}
+
+fn metadata_vtable() {
+    let p = &0i32 as &dyn std::fmt::Debug;
+    let meta: ptr::DynMetadata<_> = ptr::metadata(p as *const _);
+    assert_eq!(meta.size_of(), mem::size_of::<i32>());
+    assert_eq!(meta.align_of(), mem::align_of::<i32>());
+
+    type T = [i32; 16];
+    let p = &T::default() as &dyn std::fmt::Debug;
+    let meta: ptr::DynMetadata<_> = ptr::metadata(p as *const _);
+    assert_eq!(meta.size_of(), mem::size_of::<T>());
+    assert_eq!(meta.align_of(), mem::align_of::<T>());
+}
+
+fn main() {
+    assert_eq!(one_line_ref(), 1);
+    assert_eq!(basic_ref(), 1);
+    assert_eq!(basic_ref_mut(), 3);
+    assert_eq!(basic_ref_mut_var(), 3);
+    assert_eq!(tuple_ref_mut(), (10, 22));
+    assert_eq!(match_ref_mut(), 42);
+
+    // Compare even dangling pointers with NULL, and with others in the same allocation, including
+    // out-of-bounds.
+    assert!(dangling_pointer() != std::ptr::null());
+    assert!(match dangling_pointer() as usize {
+        0 => false,
+        _ => true,
+    });
+    let dangling = dangling_pointer();
+    assert!(dangling == dangling);
+    assert!(dangling.wrapping_add(1) != dangling);
+    assert!(dangling.wrapping_sub(1) != dangling);
+
+    // Compare pointer with BIG integers
+    let dangling = dangling as usize;
+    assert!(dangling != usize::MAX);
+    assert!(dangling != usize::MAX - 1);
+    assert!(dangling != usize::MAX - 2);
+    assert!(dangling != usize::MAX - 3); // this is even 4-aligned, but it still cannot be equal because of the extra "room" after this pointer
+    assert_eq!((usize::MAX - 3) % 4, 0); // just to be sure we got this right
+
+    // Compare pointer with unaligned integers
+    assert!(dangling != 1usize);
+    assert!(dangling != 2usize);
+    assert!(dangling != 3usize);
+    // 4 is a possible choice! So we cannot compare with that.
+    assert!(dangling != 5usize);
+    assert!(dangling != 6usize);
+    assert!(dangling != 7usize);
+
+    // Using inequality to do the comparison.
+    assert!(dangling > 0);
+    assert!(dangling > 1);
+    assert!(dangling > 2);
+    assert!(dangling > 3);
+    assert!(dangling >= 4);
+
+    // CTFE-specific equality tests, need to also work at runtime.
+    let addr = &13 as *const i32;
+    let addr2 = (addr as usize).wrapping_add(usize::MAX).wrapping_add(1);
+    assert_eq!(addr.guaranteed_eq(addr2 as *const _), Some(true));
+    assert_eq!(addr.guaranteed_ne(0x100 as *const _), Some(true));
+
+    wide_ptr_ops();
+    metadata_vtable();
+}
diff --git a/src/tools/miri/tests/pass/portable-simd.rs b/src/tools/miri/tests/pass/portable-simd.rs
new file mode 100644
index 000000000000..173ac654b03d
--- /dev/null
+++ b/src/tools/miri/tests/pass/portable-simd.rs
@@ -0,0 +1,396 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(portable_simd, platform_intrinsics)]
+use std::simd::*;
+
+fn simd_ops_f32() {
+    let a = f32x4::splat(10.0);
+    let b = f32x4::from_array([1.0, 2.0, 3.0, -4.0]);
+    assert_eq!(-b, f32x4::from_array([-1.0, -2.0, -3.0, 4.0]));
+    assert_eq!(a + b, f32x4::from_array([11.0, 12.0, 13.0, 6.0]));
+    assert_eq!(a - b, f32x4::from_array([9.0, 8.0, 7.0, 14.0]));
+    assert_eq!(a * b, f32x4::from_array([10.0, 20.0, 30.0, -40.0]));
+    assert_eq!(b / a, f32x4::from_array([0.1, 0.2, 0.3, -0.4]));
+    assert_eq!(a / f32x4::splat(2.0), f32x4::splat(5.0));
+    assert_eq!(a % b, f32x4::from_array([0.0, 0.0, 1.0, 2.0]));
+    assert_eq!(b.abs(), f32x4::from_array([1.0, 2.0, 3.0, 4.0]));
+    assert_eq!(a.simd_max(b * f32x4::splat(4.0)), f32x4::from_array([10.0, 10.0, 12.0, 10.0]));
+    assert_eq!(a.simd_min(b * f32x4::splat(4.0)), f32x4::from_array([4.0, 8.0, 10.0, -16.0]));
+
+    assert_eq!(a.mul_add(b, a), (a * b) + a);
+    assert_eq!(b.mul_add(b, a), (b * b) + a);
+    assert_eq!(a.mul_add(b, b), (a * b) + b);
+    assert_eq!(
+        f32x4::splat(-3.2).mul_add(b, f32x4::splat(f32::NEG_INFINITY)),
+        f32x4::splat(f32::NEG_INFINITY)
+    );
+    assert_eq!((a * a).sqrt(), a);
+    assert_eq!((b * b).sqrt(), b.abs());
+
+    assert_eq!(a.simd_eq(f32x4::splat(5.0) * b), Mask::from_array([false, true, false, false]));
+    assert_eq!(a.simd_ne(f32x4::splat(5.0) * b), Mask::from_array([true, false, true, true]));
+    assert_eq!(a.simd_le(f32x4::splat(5.0) * b), Mask::from_array([false, true, true, false]));
+    assert_eq!(a.simd_lt(f32x4::splat(5.0) * b), Mask::from_array([false, false, true, false]));
+    assert_eq!(a.simd_ge(f32x4::splat(5.0) * b), Mask::from_array([true, true, false, true]));
+    assert_eq!(a.simd_gt(f32x4::splat(5.0) * b), Mask::from_array([true, false, false, true]));
+
+    assert_eq!(a.reduce_sum(), 40.0);
+    assert_eq!(b.reduce_sum(), 2.0);
+    assert_eq!(a.reduce_product(), 100.0 * 100.0);
+    assert_eq!(b.reduce_product(), -24.0);
+    assert_eq!(a.reduce_max(), 10.0);
+    assert_eq!(b.reduce_max(), 3.0);
+    assert_eq!(a.reduce_min(), 10.0);
+    assert_eq!(b.reduce_min(), -4.0);
+
+    assert_eq!(
+        f32x2::from_array([0.0, f32::NAN]).simd_max(f32x2::from_array([f32::NAN, 0.0])),
+        f32x2::from_array([0.0, 0.0])
+    );
+    assert_eq!(f32x2::from_array([0.0, f32::NAN]).reduce_max(), 0.0);
+    assert_eq!(f32x2::from_array([f32::NAN, 0.0]).reduce_max(), 0.0);
+    assert_eq!(
+        f32x2::from_array([0.0, f32::NAN]).simd_min(f32x2::from_array([f32::NAN, 0.0])),
+        f32x2::from_array([0.0, 0.0])
+    );
+    assert_eq!(f32x2::from_array([0.0, f32::NAN]).reduce_min(), 0.0);
+    assert_eq!(f32x2::from_array([f32::NAN, 0.0]).reduce_min(), 0.0);
+}
+
+fn simd_ops_f64() {
+    let a = f64x4::splat(10.0);
+    let b = f64x4::from_array([1.0, 2.0, 3.0, -4.0]);
+    assert_eq!(-b, f64x4::from_array([-1.0, -2.0, -3.0, 4.0]));
+    assert_eq!(a + b, f64x4::from_array([11.0, 12.0, 13.0, 6.0]));
+    assert_eq!(a - b, f64x4::from_array([9.0, 8.0, 7.0, 14.0]));
+    assert_eq!(a * b, f64x4::from_array([10.0, 20.0, 30.0, -40.0]));
+    assert_eq!(b / a, f64x4::from_array([0.1, 0.2, 0.3, -0.4]));
+    assert_eq!(a / f64x4::splat(2.0), f64x4::splat(5.0));
+    assert_eq!(a % b, f64x4::from_array([0.0, 0.0, 1.0, 2.0]));
+    assert_eq!(b.abs(), f64x4::from_array([1.0, 2.0, 3.0, 4.0]));
+    assert_eq!(a.simd_max(b * f64x4::splat(4.0)), f64x4::from_array([10.0, 10.0, 12.0, 10.0]));
+    assert_eq!(a.simd_min(b * f64x4::splat(4.0)), f64x4::from_array([4.0, 8.0, 10.0, -16.0]));
+
+    assert_eq!(a.mul_add(b, a), (a * b) + a);
+    assert_eq!(b.mul_add(b, a), (b * b) + a);
+    assert_eq!(a.mul_add(b, b), (a * b) + b);
+    assert_eq!(
+        f64x4::splat(-3.2).mul_add(b, f64x4::splat(f64::NEG_INFINITY)),
+        f64x4::splat(f64::NEG_INFINITY)
+    );
+    assert_eq!((a * a).sqrt(), a);
+    assert_eq!((b * b).sqrt(), b.abs());
+
+    assert_eq!(a.simd_eq(f64x4::splat(5.0) * b), Mask::from_array([false, true, false, false]));
+    assert_eq!(a.simd_ne(f64x4::splat(5.0) * b), Mask::from_array([true, false, true, true]));
+    assert_eq!(a.simd_le(f64x4::splat(5.0) * b), Mask::from_array([false, true, true, false]));
+    assert_eq!(a.simd_lt(f64x4::splat(5.0) * b), Mask::from_array([false, false, true, false]));
+    assert_eq!(a.simd_ge(f64x4::splat(5.0) * b), Mask::from_array([true, true, false, true]));
+    assert_eq!(a.simd_gt(f64x4::splat(5.0) * b), Mask::from_array([true, false, false, true]));
+
+    assert_eq!(a.reduce_sum(), 40.0);
+    assert_eq!(b.reduce_sum(), 2.0);
+    assert_eq!(a.reduce_product(), 100.0 * 100.0);
+    assert_eq!(b.reduce_product(), -24.0);
+    assert_eq!(a.reduce_max(), 10.0);
+    assert_eq!(b.reduce_max(), 3.0);
+    assert_eq!(a.reduce_min(), 10.0);
+    assert_eq!(b.reduce_min(), -4.0);
+
+    assert_eq!(
+        f64x2::from_array([0.0, f64::NAN]).simd_max(f64x2::from_array([f64::NAN, 0.0])),
+        f64x2::from_array([0.0, 0.0])
+    );
+    assert_eq!(f64x2::from_array([0.0, f64::NAN]).reduce_max(), 0.0);
+    assert_eq!(f64x2::from_array([f64::NAN, 0.0]).reduce_max(), 0.0);
+    assert_eq!(
+        f64x2::from_array([0.0, f64::NAN]).simd_min(f64x2::from_array([f64::NAN, 0.0])),
+        f64x2::from_array([0.0, 0.0])
+    );
+    assert_eq!(f64x2::from_array([0.0, f64::NAN]).reduce_min(), 0.0);
+    assert_eq!(f64x2::from_array([f64::NAN, 0.0]).reduce_min(), 0.0);
+}
+
+fn simd_ops_i32() {
+    let a = i32x4::splat(10);
+    let b = i32x4::from_array([1, 2, 3, -4]);
+    assert_eq!(-b, i32x4::from_array([-1, -2, -3, 4]));
+    assert_eq!(a + b, i32x4::from_array([11, 12, 13, 6]));
+    assert_eq!(a - b, i32x4::from_array([9, 8, 7, 14]));
+    assert_eq!(a * b, i32x4::from_array([10, 20, 30, -40]));
+    assert_eq!(a / b, i32x4::from_array([10, 5, 3, -2]));
+    assert_eq!(a / i32x4::splat(2), i32x4::splat(5));
+    assert_eq!(i32x2::splat(i32::MIN) / i32x2::splat(-1), i32x2::splat(i32::MIN));
+    assert_eq!(a % b, i32x4::from_array([0, 0, 1, 2]));
+    assert_eq!(i32x2::splat(i32::MIN) % i32x2::splat(-1), i32x2::splat(0));
+    assert_eq!(b.abs(), i32x4::from_array([1, 2, 3, 4]));
+    assert_eq!(a.simd_max(b * i32x4::splat(4)), i32x4::from_array([10, 10, 12, 10]));
+    assert_eq!(a.simd_min(b * i32x4::splat(4)), i32x4::from_array([4, 8, 10, -16]));
+
+    assert_eq!(
+        i8x4::from_array([i8::MAX, -23, 23, i8::MIN]).saturating_add(i8x4::from_array([
+            1,
+            i8::MIN,
+            i8::MAX,
+            28
+        ])),
+        i8x4::from_array([i8::MAX, i8::MIN, i8::MAX, -100])
+    );
+    assert_eq!(
+        i8x4::from_array([i8::MAX, -28, 27, 42]).saturating_sub(i8x4::from_array([
+            1,
+            i8::MAX,
+            i8::MAX,
+            -80
+        ])),
+        i8x4::from_array([126, i8::MIN, -100, 122])
+    );
+    assert_eq!(
+        u8x4::from_array([u8::MAX, 0, 23, 42]).saturating_add(u8x4::from_array([
+            1,
+            1,
+            u8::MAX,
+            200
+        ])),
+        u8x4::from_array([u8::MAX, 1, u8::MAX, 242])
+    );
+    assert_eq!(
+        u8x4::from_array([u8::MAX, 0, 23, 42]).saturating_sub(u8x4::from_array([
+            1,
+            1,
+            u8::MAX,
+            200
+        ])),
+        u8x4::from_array([254, 0, 0, 0])
+    );
+
+    assert_eq!(!b, i32x4::from_array([!1, !2, !3, !-4]));
+    assert_eq!(b << i32x4::splat(2), i32x4::from_array([4, 8, 12, -16]));
+    assert_eq!(b >> i32x4::splat(1), i32x4::from_array([0, 1, 1, -2]));
+    assert_eq!(b & i32x4::splat(2), i32x4::from_array([0, 2, 2, 0]));
+    assert_eq!(b | i32x4::splat(2), i32x4::from_array([3, 2, 3, -2]));
+    assert_eq!(b ^ i32x4::splat(2), i32x4::from_array([3, 0, 1, -2]));
+
+    assert_eq!(a.simd_eq(i32x4::splat(5) * b), Mask::from_array([false, true, false, false]));
+    assert_eq!(a.simd_ne(i32x4::splat(5) * b), Mask::from_array([true, false, true, true]));
+    assert_eq!(a.simd_le(i32x4::splat(5) * b), Mask::from_array([false, true, true, false]));
+    assert_eq!(a.simd_lt(i32x4::splat(5) * b), Mask::from_array([false, false, true, false]));
+    assert_eq!(a.simd_ge(i32x4::splat(5) * b), Mask::from_array([true, true, false, true]));
+    assert_eq!(a.simd_gt(i32x4::splat(5) * b), Mask::from_array([true, false, false, true]));
+
+    assert_eq!(a.reduce_sum(), 40);
+    assert_eq!(b.reduce_sum(), 2);
+    assert_eq!(a.reduce_product(), 100 * 100);
+    assert_eq!(b.reduce_product(), -24);
+    assert_eq!(a.reduce_max(), 10);
+    assert_eq!(b.reduce_max(), 3);
+    assert_eq!(a.reduce_min(), 10);
+    assert_eq!(b.reduce_min(), -4);
+
+    assert_eq!(a.reduce_and(), 10);
+    assert_eq!(b.reduce_and(), 0);
+    assert_eq!(a.reduce_or(), 10);
+    assert_eq!(b.reduce_or(), -1);
+    assert_eq!(a.reduce_xor(), 0);
+    assert_eq!(b.reduce_xor(), -4);
+}
+
+fn simd_mask() {
+    let intmask = Mask::from_int(i32x4::from_array([0, -1, 0, 0]));
+    assert_eq!(intmask, Mask::from_array([false, true, false, false]));
+    assert_eq!(intmask.to_array(), [false, true, false, false]);
+
+    let values = [
+        true, false, false, true, false, false, true, false, true, true, false, false, false, true,
+        false, true,
+    ];
+    let mask = Mask::<i64, 16>::from_array(values);
+    let bitmask = mask.to_bitmask();
+    assert_eq!(bitmask, 0b1010001101001001);
+    assert_eq!(Mask::<i64, 16>::from_bitmask(bitmask), mask);
+
+    let values = [false, false, false, true];
+    let mask = Mask::<i64, 4>::from_array(values);
+    let bitmask = mask.to_bitmask();
+    assert_eq!(bitmask, 0b1000);
+    assert_eq!(Mask::<i64, 4>::from_bitmask(bitmask), mask);
+}
+
+fn simd_cast() {
+    // between integer types
+    assert_eq!(i32x4::from_array([1, 2, 3, -4]), i16x4::from_array([1, 2, 3, -4]).cast());
+    assert_eq!(i16x4::from_array([1, 2, 3, -4]), i32x4::from_array([1, 2, 3, -4]).cast());
+    assert_eq!(i32x4::from_array([1, -1, 3, 4]), u64x4::from_array([1, u64::MAX, 3, 4]).cast());
+
+    // float -> int
+    assert_eq!(
+        i8x4::from_array([127, -128, 127, -128]),
+        f32x4::from_array([127.99, -128.99, 999.0, -999.0]).cast()
+    );
+    assert_eq!(
+        i32x4::from_array([0, 1, -1, 2147483520]),
+        f32x4::from_array([
+            -0.0,
+            /*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd),
+            /*-0x1.19999ap+0*/ f32::from_bits(0xbf8ccccd),
+            2147483520.0
+        ])
+        .cast()
+    );
+    assert_eq!(
+        i32x8::from_array([i32::MAX, i32::MIN, i32::MAX, i32::MIN, i32::MAX, i32::MIN, 0, 0]),
+        f32x8::from_array([
+            2147483648.0f32,
+            -2147483904.0f32,
+            f32::MAX,
+            f32::MIN,
+            f32::INFINITY,
+            f32::NEG_INFINITY,
+            f32::NAN,
+            -f32::NAN,
+        ])
+        .cast()
+    );
+
+    // int -> float
+    assert_eq!(
+        f32x4::from_array([
+            -2147483648.0,
+            /*0x1.26580cp+30*/ f32::from_bits(0x4e932c06),
+            16777220.0,
+            -16777220.0,
+        ]),
+        i32x4::from_array([-2147483647i32, 1234567890i32, 16777219i32, -16777219i32]).cast()
+    );
+
+    // float -> float
+    assert_eq!(
+        f32x4::from_array([f32::INFINITY, f32::INFINITY, f32::NEG_INFINITY, f32::NEG_INFINITY]),
+        f64x4::from_array([f64::MAX, f64::INFINITY, f64::MIN, f64::NEG_INFINITY]).cast()
+    );
+
+    // unchecked casts
+    unsafe {
+        assert_eq!(
+            i32x4::from_array([0, 1, -1, 2147483520]),
+            f32x4::from_array([
+                -0.0,
+                /*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd),
+                /*-0x1.19999ap+0*/ f32::from_bits(0xbf8ccccd),
+                2147483520.0
+            ])
+            .to_int_unchecked()
+        );
+        assert_eq!(
+            u64x4::from_array([0, 10000000000000000, u64::MAX - 2047, 9223372036854775808]),
+            f64x4::from_array([
+                -0.99999999999,
+                1e16,
+                (u64::MAX - 1024) as f64,
+                9223372036854775808.0
+            ])
+            .to_int_unchecked()
+        );
+    }
+}
+
+fn simd_swizzle() {
+    use Which::*;
+
+    let a = f32x4::splat(10.0);
+    let b = f32x4::from_array([1.0, 2.0, 3.0, -4.0]);
+
+    assert_eq!(simd_swizzle!(b, [3, 0, 0, 2]), f32x4::from_array([-4.0, 1.0, 1.0, 3.0]));
+    assert_eq!(simd_swizzle!(b, [1, 2]), f32x2::from_array([2.0, 3.0]));
+    assert_eq!(simd_swizzle!(b, a, [First(3), Second(0)]), f32x2::from_array([-4.0, 10.0]));
+}
+
+fn simd_gather_scatter() {
+    let mut vec: Vec<i16> = vec![10, 11, 12, 13, 14, 15, 16, 17, 18];
+    let idxs = Simd::from_array([9, 3, 0, 17]);
+    let result = Simd::gather_or_default(&vec, idxs); // Note the lane that is out-of-bounds.
+    assert_eq!(result, Simd::from_array([0, 13, 10, 0]));
+
+    let idxs = Simd::from_array([9, 3, 0, 0]);
+    Simd::from_array([-27, 82, -41, 124]).scatter(&mut vec, idxs);
+    assert_eq!(vec, vec![124, 11, 12, 82, 14, 15, 16, 17, 18]);
+}
+
+fn simd_round() {
+    assert_eq!(
+        f32x4::from_array([0.9, 1.001, 2.0, -4.5]).ceil(),
+        f32x4::from_array([1.0, 2.0, 2.0, -4.0])
+    );
+    assert_eq!(
+        f32x4::from_array([0.9, 1.001, 2.0, -4.5]).floor(),
+        f32x4::from_array([0.0, 1.0, 2.0, -5.0])
+    );
+    assert_eq!(
+        f32x4::from_array([0.9, 1.001, 2.0, -4.5]).round(),
+        f32x4::from_array([1.0, 1.0, 2.0, -5.0])
+    );
+    assert_eq!(
+        f32x4::from_array([0.9, 1.001, 2.0, -4.5]).trunc(),
+        f32x4::from_array([0.0, 1.0, 2.0, -4.0])
+    );
+
+    assert_eq!(
+        f64x4::from_array([0.9, 1.001, 2.0, -4.5]).ceil(),
+        f64x4::from_array([1.0, 2.0, 2.0, -4.0])
+    );
+    assert_eq!(
+        f64x4::from_array([0.9, 1.001, 2.0, -4.5]).floor(),
+        f64x4::from_array([0.0, 1.0, 2.0, -5.0])
+    );
+    assert_eq!(
+        f64x4::from_array([0.9, 1.001, 2.0, -4.5]).round(),
+        f64x4::from_array([1.0, 1.0, 2.0, -5.0])
+    );
+    assert_eq!(
+        f64x4::from_array([0.9, 1.001, 2.0, -4.5]).trunc(),
+        f64x4::from_array([0.0, 1.0, 2.0, -4.0])
+    );
+}
+
+fn simd_intrinsics() {
+    extern "platform-intrinsic" {
+        fn simd_eq<T, U>(x: T, y: T) -> U;
+        fn simd_reduce_any<T>(x: T) -> bool;
+        fn simd_reduce_all<T>(x: T) -> bool;
+        fn simd_select<M, T>(m: M, yes: T, no: T) -> T;
+    }
+    unsafe {
+        // Make sure simd_eq returns all-1 for `true`
+        let a = i32x4::splat(10);
+        let b = i32x4::from_array([1, 2, 10, 4]);
+        let c: i32x4 = simd_eq(a, b);
+        assert_eq!(c, i32x4::from_array([0, 0, -1, 0]));
+
+        assert!(!simd_reduce_any(i32x4::splat(0)));
+        assert!(simd_reduce_any(i32x4::splat(-1)));
+        assert!(simd_reduce_any(i32x2::from_array([0, -1])));
+        assert!(!simd_reduce_all(i32x4::splat(0)));
+        assert!(simd_reduce_all(i32x4::splat(-1)));
+        assert!(!simd_reduce_all(i32x2::from_array([0, -1])));
+
+        assert_eq!(
+            simd_select(i8x4::from_array([0, -1, -1, 0]), a, b),
+            i32x4::from_array([1, 10, 10, 4])
+        );
+        assert_eq!(
+            simd_select(i8x4::from_array([0, -1, -1, 0]), b, a),
+            i32x4::from_array([10, 2, 10, 10])
+        );
+    }
+}
+
+fn main() {
+    simd_mask();
+    simd_ops_f32();
+    simd_ops_f64();
+    simd_ops_i32();
+    simd_cast();
+    simd_swizzle();
+    simd_gather_scatter();
+    simd_round();
+    simd_intrinsics();
+}
diff --git a/src/tools/miri/tests/pass/products.rs b/src/tools/miri/tests/pass/products.rs
new file mode 100644
index 000000000000..767d756e5ae1
--- /dev/null
+++ b/src/tools/miri/tests/pass/products.rs
@@ -0,0 +1,35 @@
+fn tuple() -> (i16,) {
+    (1,)
+}
+
+fn tuple_2() -> (i16, i16) {
+    (1, 2)
+}
+
+fn tuple_5() -> (i16, i16, i16, i16, i16) {
+    (1, 2, 3, 4, 5)
+}
+
+#[derive(Debug, PartialEq)]
+struct Pair {
+    x: i8,
+    y: i8,
+}
+
+fn pair() -> Pair {
+    Pair { x: 10, y: 20 }
+}
+
+fn field_access() -> (i8, i8) {
+    let mut p = Pair { x: 10, y: 20 };
+    p.x += 5;
+    (p.x, p.y)
+}
+
+fn main() {
+    assert_eq!(tuple(), (1,));
+    assert_eq!(tuple_2(), (1, 2));
+    assert_eq!(tuple_5(), (1, 2, 3, 4, 5));
+    assert_eq!(pair(), Pair { x: 10, y: 20 });
+    assert_eq!(field_access(), (15, 20));
+}
diff --git a/src/tools/miri/tests/pass/ptr_int_casts.rs b/src/tools/miri/tests/pass/ptr_int_casts.rs
new file mode 100644
index 000000000000..3044ac092b7d
--- /dev/null
+++ b/src/tools/miri/tests/pass/ptr_int_casts.rs
@@ -0,0 +1,73 @@
+//@compile-flags: -Zmiri-permissive-provenance
+use std::mem;
+use std::ptr;
+
+fn eq_ref<T>(x: &T, y: &T) -> bool {
+    x as *const _ == y as *const _
+}
+
+fn f() -> i32 {
+    42
+}
+
+fn ptr_int_casts() {
+    // int-ptr-int
+    assert_eq!(1 as *const i32 as usize, 1);
+    assert_eq!((1 as *const i32).wrapping_offset(4) as usize, 1 + 4 * 4);
+
+    // negative overflowing wrapping_offset (going through memory because
+    // this used to trigger an ICE on 32bit)
+    let val = &mut ptr::null();
+    *val = (1 as *const u8).wrapping_offset(-4);
+    assert_eq!(*val as usize, usize::MAX - 2);
+
+    // ptr-int-ptr
+    {
+        let x = 13;
+        let mut y = &x as &_ as *const _ as usize;
+        y += 13;
+        y -= 13;
+        let y = y as *const _;
+        assert!(eq_ref(&x, unsafe { &*y }));
+    }
+
+    // fnptr-int-fnptr
+    {
+        let x: fn() -> i32 = f;
+        let y: *mut u8 = unsafe { mem::transmute(x as fn() -> i32) };
+        let mut y = y as usize;
+        y += 13;
+        y -= 13;
+        let x: fn() -> i32 = unsafe { mem::transmute(y as *mut u8) };
+        assert_eq!(x(), 42);
+    }
+
+    // involving types other than usize
+    assert_eq!((-1i32) as usize as *const i32 as usize, (-1i32) as usize);
+}
+
+fn ptr_int_ops() {
+    let v = [1i16, 2];
+    let x = &v[1] as *const i16 as usize;
+    // arithmetic
+    let _y = x + 4;
+    let _y = 4 + x;
+    let _y = x - 2;
+    // bit-operations, covered by alignment
+    assert_eq!(x & 1, 0);
+    assert_eq!(x & 0, 0);
+    assert_eq!(1 & (x + 1), 1);
+    let _y = !1 & x;
+    let _y = !0 & x;
+    let _y = x & !1;
+    // remainder, covered by alignment
+    assert_eq!(x % 2, 0);
+    assert_eq!((x + 1) % 2, 1);
+    // remainder with 1 is always 0
+    assert_eq!(x % 1, 0);
+}
+
+fn main() {
+    ptr_int_casts();
+    ptr_int_ops();
+}
diff --git a/src/tools/miri/tests/pass/ptr_int_from_exposed.rs b/src/tools/miri/tests/pass/ptr_int_from_exposed.rs
new file mode 100644
index 000000000000..ef7ff34d26b2
--- /dev/null
+++ b/src/tools/miri/tests/pass/ptr_int_from_exposed.rs
@@ -0,0 +1,62 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(strict_provenance)]
+
+use std::ptr;
+
+/// Ensure we can expose the address of a pointer that is out-of-bounds
+fn ptr_roundtrip_out_of_bounds() {
+    let x: i32 = 3;
+    let x_ptr = &x as *const i32;
+
+    let x_usize = x_ptr.wrapping_offset(128).expose_addr();
+
+    let ptr = ptr::from_exposed_addr::<i32>(x_usize).wrapping_offset(-128);
+    assert_eq!(unsafe { *ptr }, 3);
+}
+
+/// Ensure that we can move between allocations after casting back to a ptr
+fn ptr_roundtrip_confusion() {
+    let x: i32 = 0;
+    let y: i32 = 1;
+
+    let x_ptr = &x as *const i32;
+    let y_ptr = &y as *const i32;
+
+    let x_usize = x_ptr.expose_addr();
+    let y_usize = y_ptr.expose_addr();
+
+    let ptr = ptr::from_exposed_addr::<i32>(y_usize);
+    let ptr = ptr.with_addr(x_usize);
+    assert_eq!(unsafe { *ptr }, 0);
+}
+
+/// Ensure we can cast back a different integer than the one we got when exposing.
+fn ptr_roundtrip_imperfect() {
+    let x: u8 = 3;
+    let x_ptr = &x as *const u8;
+
+    let x_usize = x_ptr.expose_addr() + 128;
+
+    let ptr = ptr::from_exposed_addr::<u8>(x_usize).wrapping_offset(-128);
+    assert_eq!(unsafe { *ptr }, 3);
+}
+
+/// Ensure that we can roundtrip through a pointer with an address of 0
+fn ptr_roundtrip_null() {
+    let x = &42;
+    let x_ptr = x as *const i32;
+    let x_null_ptr = x_ptr.with_addr(0); // addr 0, but still the provenance of x
+    let null = x_null_ptr.expose_addr();
+    assert_eq!(null, 0);
+
+    let x_null_ptr_copy = ptr::from_exposed_addr::<i32>(null); // just a roundtrip, so has provenance of x (angelically)
+    let x_ptr_copy = x_null_ptr_copy.with_addr(x_ptr.addr()); // addr of x and provenance of x
+    assert_eq!(unsafe { *x_ptr_copy }, 42);
+}
+
+fn main() {
+    ptr_roundtrip_out_of_bounds();
+    ptr_roundtrip_confusion();
+    ptr_roundtrip_imperfect();
+    ptr_roundtrip_null();
+}
diff --git a/src/tools/miri/tests/pass/ptr_int_transmute.rs b/src/tools/miri/tests/pass/ptr_int_transmute.rs
new file mode 100644
index 000000000000..ba50480c5399
--- /dev/null
+++ b/src/tools/miri/tests/pass/ptr_int_transmute.rs
@@ -0,0 +1,22 @@
+// Test what happens when we read parts of a pointer.
+// Related to <https://github.com/rust-lang/rust/issues/69488>.
+fn ptr_partial_read() {
+    let x = 13;
+    let y = &x;
+    let z = &y as *const &i32 as *const u8;
+
+    // This just strips provenance, but should work fine otherwise.
+    let _val = unsafe { *z };
+}
+
+fn transmute_strip_provenance() {
+    let r = &mut 42;
+    let addr = r as *mut _ as usize;
+    let i: usize = unsafe { std::mem::transmute(r) };
+    assert_eq!(i, addr);
+}
+
+fn main() {
+    ptr_partial_read();
+    transmute_strip_provenance();
+}
diff --git a/src/tools/miri/tests/pass/ptr_offset.rs b/src/tools/miri/tests/pass/ptr_offset.rs
new file mode 100644
index 000000000000..95eac8522fb4
--- /dev/null
+++ b/src/tools/miri/tests/pass/ptr_offset.rs
@@ -0,0 +1,92 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(ptr_sub_ptr)]
+use std::{mem, ptr};
+
+fn main() {
+    smoke();
+    test_offset_from();
+    test_vec_into_iter();
+    ptr_arith_offset();
+    ptr_arith_offset_overflow();
+    ptr_offset();
+}
+
+fn smoke() {
+    // Smoke-test various offsetting operations.
+    let ptr = &5;
+    let ptr = ptr as *const i32;
+    let _val = ptr.wrapping_offset(0);
+    let _val = unsafe { ptr.offset(0) };
+    let _val = ptr.wrapping_add(0);
+    let _val = unsafe { ptr.add(0) };
+    let _val = ptr.wrapping_sub(0);
+    let _val = unsafe { ptr.sub(0) };
+    let _val = unsafe { ptr.offset_from(ptr) };
+    let _val = unsafe { ptr.sub_ptr(ptr) };
+}
+
+fn test_offset_from() {
+    unsafe {
+        let buf = [0u32; 4];
+
+        let x = buf.as_ptr() as *const u8;
+        let y = x.offset(12);
+
+        assert_eq!(y.offset_from(x), 12);
+        assert_eq!(y.sub_ptr(x), 12);
+        assert_eq!(x.offset_from(y), -12);
+        assert_eq!((y as *const u32).offset_from(x as *const u32), 12 / 4);
+        assert_eq!((x as *const u32).offset_from(y as *const u32), -12 / 4);
+
+        let x = (((x as usize) * 2) / 2) as *const u8;
+        assert_eq!(y.offset_from(x), 12);
+        assert_eq!(y.sub_ptr(x), 12);
+        assert_eq!(x.offset_from(y), -12);
+    }
+}
+
+// This also internally uses offset_from.
+fn test_vec_into_iter() {
+    let v = Vec::<i32>::new();
+    let i = v.into_iter();
+    i.size_hint();
+}
+
+fn ptr_arith_offset() {
+    let v = [1i16, 2];
+    let x = &v as *const [i16] as *const i16;
+    let x = x.wrapping_offset(1);
+    assert_eq!(unsafe { *x }, 2);
+}
+
+fn ptr_arith_offset_overflow() {
+    let v = [1i16, 2];
+    let x = &mut ptr::null(); // going through memory as there are more sanity checks along that path
+    *x = v.as_ptr().wrapping_offset(1); // ptr to the 2nd element
+    // Adding 2*isize::max and then 1 is like substracting 1
+    *x = x.wrapping_offset(isize::MAX);
+    *x = x.wrapping_offset(isize::MAX);
+    *x = x.wrapping_offset(1);
+    assert_eq!(unsafe { **x }, 1);
+}
+
+fn ptr_offset() {
+    fn f() -> i32 {
+        42
+    }
+
+    let v = [1i16, 2];
+    let x = &v as *const [i16; 2] as *const i16;
+    let x = unsafe { x.offset(1) };
+    assert_eq!(unsafe { *x }, 2);
+
+    // fn ptr offset
+    unsafe {
+        let p = f as fn() -> i32 as usize;
+        let x = (p as *mut u32).offset(0) as usize;
+        // *cast* to ptr, then transmute to fn ptr.
+        // (transmuting int to [fn]ptr causes trouble.)
+        let f: fn() -> i32 = mem::transmute(x as *const ());
+        assert_eq!(f(), 42);
+    }
+}
diff --git a/src/tools/miri/tests/pass/ptr_raw.rs b/src/tools/miri/tests/pass/ptr_raw.rs
new file mode 100644
index 000000000000..3ba0fba9a941
--- /dev/null
+++ b/src/tools/miri/tests/pass/ptr_raw.rs
@@ -0,0 +1,25 @@
+fn basic_raw() {
+    let mut x = 12;
+    let x = &mut x;
+
+    assert_eq!(*x, 12);
+
+    let raw = x as *mut i32;
+    unsafe {
+        *raw = 42;
+    }
+
+    assert_eq!(*x, 42);
+
+    let raw = x as *mut i32;
+    unsafe {
+        *raw = 12;
+    }
+    *x = 23;
+
+    assert_eq!(*x, 23);
+}
+
+fn main() {
+    basic_raw();
+}
diff --git a/src/tools/miri/tests/pass/rc.rs b/src/tools/miri/tests/pass/rc.rs
new file mode 100644
index 000000000000..569dbc459a5b
--- /dev/null
+++ b/src/tools/miri/tests/pass/rc.rs
@@ -0,0 +1,153 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(new_uninit)]
+#![feature(get_mut_unchecked)]
+
+use std::cell::{Cell, RefCell};
+use std::fmt::Debug;
+use std::rc::{Rc, Weak};
+use std::sync::{Arc, Weak as ArcWeak};
+
+fn rc_refcell() {
+    let r = Rc::new(RefCell::new(42));
+    let r2 = r.clone();
+    *r.borrow_mut() += 10;
+    let x = *r2.borrow();
+    assert_eq!(x, 52);
+}
+
+fn rc_cell() {
+    let r = Rc::new(Cell::new(42));
+    let r2 = r.clone();
+    let x = r.get();
+    r2.set(x + x);
+    assert_eq!(r.get(), 84);
+}
+
+fn rc_refcell2() {
+    let r = Rc::new(RefCell::new(42));
+    let r2 = r.clone();
+    *r.borrow_mut() += 10;
+    let x = r2.borrow();
+    let r3 = r.clone();
+    let y = r3.borrow();
+    assert_eq!((*x + *y) / 2, 52);
+}
+
+fn rc_raw() {
+    let r = Rc::new(0);
+    let r2 = Rc::into_raw(r.clone());
+    let r2 = unsafe { Rc::from_raw(r2) };
+    assert!(Rc::ptr_eq(&r, &r2));
+    drop(r);
+    assert!(Rc::try_unwrap(r2).is_ok());
+}
+
+fn arc() {
+    fn test() -> Arc<i32> {
+        let a = Arc::new(42);
+        a
+    }
+    assert_eq!(*test(), 42);
+
+    let raw = ArcWeak::into_raw(ArcWeak::<usize>::new());
+    drop(unsafe { ArcWeak::from_raw(raw) });
+}
+
+// Make sure this Rc doesn't fall apart when touched
+fn check_unique_rc<T: ?Sized>(mut r: Rc<T>) {
+    let r2 = r.clone();
+    assert!(Rc::get_mut(&mut r).is_none());
+    drop(r2);
+    assert!(Rc::get_mut(&mut r).is_some());
+}
+
+fn rc_from() {
+    check_unique_rc::<[_]>(Rc::from(&[1, 2, 3] as &[_]));
+    check_unique_rc::<[_]>(Rc::from(vec![1, 2, 3]));
+    check_unique_rc::<[_]>(Rc::from(Box::new([1, 2, 3]) as Box<[_]>));
+    check_unique_rc::<str>(Rc::from("Hello, World!"));
+}
+
+fn rc_fat_ptr_eq() {
+    let p = Rc::new(1) as Rc<dyn Debug>;
+    let a: *const dyn Debug = &*p;
+    let r = Rc::into_raw(p);
+    assert!(a == r);
+    drop(unsafe { Rc::from_raw(r) });
+}
+
+/// Taken from the `Weak::into_raw` doctest.
+fn weak_into_raw() {
+    let strong = Rc::new(42);
+    let weak = Rc::downgrade(&strong);
+    let raw = Weak::into_raw(weak);
+
+    assert_eq!(1, Rc::weak_count(&strong));
+    assert_eq!(42, unsafe { *raw });
+
+    drop(unsafe { Weak::from_raw(raw) });
+    assert_eq!(0, Rc::weak_count(&strong));
+
+    let raw = Weak::into_raw(Weak::<usize>::new());
+    drop(unsafe { Weak::from_raw(raw) });
+}
+
+/// Taken from the `Weak::from_raw` doctest.
+fn weak_from_raw() {
+    let strong = Rc::new(42);
+
+    let raw_1 = Weak::into_raw(Rc::downgrade(&strong));
+    let raw_2 = Weak::into_raw(Rc::downgrade(&strong));
+
+    assert_eq!(2, Rc::weak_count(&strong));
+
+    assert_eq!(42, *Weak::upgrade(&unsafe { Weak::from_raw(raw_1) }).unwrap());
+    assert_eq!(1, Rc::weak_count(&strong));
+
+    drop(strong);
+
+    // Decrement the last weak count.
+    assert!(Weak::upgrade(&unsafe { Weak::from_raw(raw_2) }).is_none());
+}
+
+fn rc_uninit() {
+    let mut five = Rc::<Box<u32>>::new_uninit();
+    let five = unsafe {
+        // Deferred initialization:
+        Rc::get_mut_unchecked(&mut five).as_mut_ptr().write(Box::new(5));
+        five.assume_init()
+    };
+    assert_eq!(**five, 5)
+}
+
+fn rc_uninit_slice() {
+    let mut values = Rc::<[Box<usize>]>::new_uninit_slice(3);
+
+    let values = unsafe {
+        // Deferred initialization:
+        Rc::get_mut_unchecked(&mut values)[0].as_mut_ptr().write(Box::new(0));
+        Rc::get_mut_unchecked(&mut values)[1].as_mut_ptr().write(Box::new(1));
+        Rc::get_mut_unchecked(&mut values)[2].as_mut_ptr().write(Box::new(2));
+
+        values.assume_init()
+    };
+
+    for (idx, i) in values.iter().enumerate() {
+        assert_eq!(idx, **i);
+    }
+}
+
+fn main() {
+    rc_fat_ptr_eq();
+    rc_refcell();
+    rc_refcell2();
+    rc_cell();
+    rc_raw();
+    rc_from();
+    weak_into_raw();
+    weak_from_raw();
+    rc_uninit();
+    rc_uninit_slice();
+
+    arc();
+}
diff --git a/src/tools/miri/tests/pass/recursive_static.rs b/src/tools/miri/tests/pass/recursive_static.rs
new file mode 100644
index 000000000000..77f2902917a1
--- /dev/null
+++ b/src/tools/miri/tests/pass/recursive_static.rs
@@ -0,0 +1,9 @@
+struct S(&'static S);
+static S1: S = S(&S2);
+static S2: S = S(&S1);
+
+fn main() {
+    let p: *const S = S2.0;
+    let q: *const S = &S1;
+    assert_eq!(p, q);
+}
diff --git a/src/tools/miri/tests/pass/reentrant-println.rs b/src/tools/miri/tests/pass/reentrant-println.rs
new file mode 100644
index 000000000000..e73e82b8ec9e
--- /dev/null
+++ b/src/tools/miri/tests/pass/reentrant-println.rs
@@ -0,0 +1,17 @@
+use std::fmt::{Display, Error, Formatter};
+
+// This test case exercises std::sys_common::remutex::ReentrantMutex
+// by calling println!() from inside fmt.
+
+struct InterruptingCow;
+
+impl Display for InterruptingCow {
+    fn fmt(&self, _f: &mut Formatter<'_>) -> Result<(), Error> {
+        println!("Moo");
+        Ok(())
+    }
+}
+
+fn main() {
+    println!("\"Knock knock\" \"Who's {} there?\"", InterruptingCow);
+}
diff --git a/src/tools/miri/tests/pass/reentrant-println.stdout b/src/tools/miri/tests/pass/reentrant-println.stdout
new file mode 100644
index 000000000000..8a57d32f84ca
--- /dev/null
+++ b/src/tools/miri/tests/pass/reentrant-println.stdout
@@ -0,0 +1,2 @@
+"Knock knock" "Who's Moo
+ there?"
diff --git a/src/tools/miri/tests/pass/regions-lifetime-nonfree-late-bound.rs b/src/tools/miri/tests/pass/regions-lifetime-nonfree-late-bound.rs
new file mode 100644
index 000000000000..c91ac36ed6b4
--- /dev/null
+++ b/src/tools/miri/tests/pass/regions-lifetime-nonfree-late-bound.rs
@@ -0,0 +1,40 @@
+// This is a regression test for the ICE from issue #10846.
+//
+// The original issue causing the ICE: the LUB-computations during
+// type inference were encountering late-bound lifetimes, and
+// asserting that such lifetimes should have already been substituted
+// with a concrete lifetime.
+//
+// However, those encounters were occurring within the lexical scope
+// of the binding for the late-bound lifetime; that is, the late-bound
+// lifetimes were perfectly valid. The core problem was that the type
+// folding code was over-zealously passing back all lifetimes when
+// doing region-folding, when really all clients of the region-folding
+// case only want to see *free* lifetime variables, not bound ones.
+
+#![feature(box_syntax)]
+
+pub fn main() {
+    fn explicit() {
+        fn test<F>(_x: Option<Box<F>>)
+        where
+            F: FnMut(Box<dyn for<'a> FnMut(&'a isize)>),
+        {
+        }
+        test(Some(box |_f: Box<dyn for<'a> FnMut(&'a isize)>| {}));
+    }
+
+    // The code below is shorthand for the code above (and more likely
+    // to represent what one encounters in practice).
+    fn implicit() {
+        fn test<F>(_x: Option<Box<F>>)
+        where
+            F: FnMut(Box<dyn FnMut(&isize)>),
+        {
+        }
+        test(Some(box |_f: Box<dyn FnMut(&isize)>| {}));
+    }
+
+    explicit();
+    implicit();
+}
diff --git a/src/tools/miri/tests/pass/rename_std.rs b/src/tools/miri/tests/pass/rename_std.rs
new file mode 100644
index 000000000000..7e82e53e6be8
--- /dev/null
+++ b/src/tools/miri/tests/pass/rename_std.rs
@@ -0,0 +1,5 @@
+#![no_std]
+
+extern crate std as foo;
+
+fn main() {}
diff --git a/src/tools/miri/tests/pass/rfc1623.rs b/src/tools/miri/tests/pass/rfc1623.rs
new file mode 100644
index 000000000000..76e2c01e7450
--- /dev/null
+++ b/src/tools/miri/tests/pass/rfc1623.rs
@@ -0,0 +1,71 @@
+#![allow(dead_code)] // tons of unused statics here...
+
+// very simple test for a 'static static with default lifetime
+static STATIC_STR: &str = "&'static str";
+const CONST_STR: &str = "&'static str";
+
+// this should be the same as without default:
+static EXPLICIT_STATIC_STR: &'static str = "&'static str";
+const EXPLICIT_CONST_STR: &'static str = "&'static str";
+
+// a function that elides to an unbound lifetime for both in- and output
+fn id_u8_slice(arg: &[u8]) -> &[u8] {
+    arg
+}
+
+// one with a function, argument elided
+static STATIC_SIMPLE_FN: &fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
+const CONST_SIMPLE_FN: &fn(&[u8]) -> &[u8] = &(id_u8_slice as fn(&[u8]) -> &[u8]);
+
+// this should be the same as without elision
+static STATIC_NON_ELIDED_FN: &for<'a> fn(&'a [u8]) -> &'a [u8] =
+    &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
+const CONST_NON_ELIDED_FN: &for<'a> fn(&'a [u8]) -> &'a [u8] =
+    &(id_u8_slice as for<'a> fn(&'a [u8]) -> &'a [u8]);
+
+// another function that elides, each to a different unbound lifetime
+fn multi_args(_a: &u8, _b: &u8, _c: &u8) {}
+
+static STATIC_MULTI_FN: &fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
+const CONST_MULTI_FN: &fn(&u8, &u8, &u8) = &(multi_args as fn(&u8, &u8, &u8));
+
+struct Foo<'a> {
+    bools: &'a [bool],
+}
+
+static STATIC_FOO: Foo = Foo { bools: &[true, false] };
+const CONST_FOO: Foo = Foo { bools: &[true, false] };
+
+type Bar<'a> = Foo<'a>;
+
+static STATIC_BAR: Bar = Bar { bools: &[true, false] };
+const CONST_BAR: Bar = Bar { bools: &[true, false] };
+
+type Baz<'a> = fn(&'a [u8]) -> Option<u8>;
+
+fn baz(e: &[u8]) -> Option<u8> {
+    e.first().map(|x| *x)
+}
+
+static STATIC_BAZ: &Baz = &(baz as Baz);
+const CONST_BAZ: &Baz = &(baz as Baz);
+
+static BYTES: &[u8] = &[1, 2, 3];
+
+fn main() {
+    // make sure that the lifetime is actually elided (and not defaulted)
+    let x = &[1u8, 2, 3];
+    STATIC_SIMPLE_FN(x);
+    CONST_SIMPLE_FN(x);
+
+    STATIC_BAZ(BYTES); // neees static lifetime
+    CONST_BAZ(BYTES);
+
+    // make sure this works with different lifetimes
+    let a = &1;
+    {
+        let b = &2;
+        let c = &3;
+        CONST_MULTI_FN(a, b, c);
+    }
+}
diff --git a/src/tools/miri/tests/pass/rust-lang-org.rs b/src/tools/miri/tests/pass/rust-lang-org.rs
new file mode 100644
index 000000000000..7ba68e6b239c
--- /dev/null
+++ b/src/tools/miri/tests/pass/rust-lang-org.rs
@@ -0,0 +1,21 @@
+// This code is editable and runnable!
+fn main() {
+    // A simple integer calculator:
+    // `+` or `-` means add or subtract by 1
+    // `*` or `/` means multiply or divide by 2
+
+    let program = "+ + * - /";
+    let mut accumulator = 0;
+
+    for token in program.chars() {
+        match token {
+            '+' => accumulator += 1,
+            '-' => accumulator -= 1,
+            '*' => accumulator *= 2,
+            '/' => accumulator /= 2,
+            _ => { /* ignore everything else */ }
+        }
+    }
+
+    assert_eq!(accumulator, 1);
+}
diff --git a/src/tools/miri/tests/pass/send-is-not-static-par-for.rs b/src/tools/miri/tests/pass/send-is-not-static-par-for.rs
new file mode 100644
index 000000000000..642f75ecc09b
--- /dev/null
+++ b/src/tools/miri/tests/pass/send-is-not-static-par-for.rs
@@ -0,0 +1,28 @@
+use std::sync::Mutex;
+
+fn par_for<I, F>(iter: I, f: F)
+where
+    I: Iterator,
+    I::Item: Send,
+    F: Fn(I::Item) + Sync,
+{
+    for item in iter {
+        f(item)
+    }
+}
+
+fn sum(x: &[i32]) {
+    let sum_lengths = Mutex::new(0);
+    par_for(x.windows(4), |x| *sum_lengths.lock().unwrap() += x.len());
+
+    assert_eq!(*sum_lengths.lock().unwrap(), (x.len() - 3) * 4);
+}
+
+fn main() {
+    let mut elements = [0; 20];
+
+    // iterators over references into this stack frame
+    par_for(elements.iter_mut().enumerate(), |(i, x)| *x = i as i32);
+
+    sum(&elements)
+}
diff --git a/src/tools/miri/tests/pass/sendable-class.rs b/src/tools/miri/tests/pass/sendable-class.rs
new file mode 100644
index 000000000000..a05278f1855a
--- /dev/null
+++ b/src/tools/miri/tests/pass/sendable-class.rs
@@ -0,0 +1,19 @@
+// Test that a class with only sendable fields can be sent
+
+use std::sync::mpsc::channel;
+
+#[allow(dead_code)]
+struct Foo {
+    i: isize,
+    j: char,
+}
+
+fn foo(i: isize, j: char) -> Foo {
+    Foo { i: i, j: j }
+}
+
+pub fn main() {
+    let (tx, rx) = channel();
+    tx.send(foo(42, 'c')).unwrap();
+    let _val = rx;
+}
diff --git a/src/tools/miri/tests/pass/shims/env/args.rs b/src/tools/miri/tests/pass/shims/env/args.rs
new file mode 100644
index 000000000000..0116dce4992d
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/args.rs
@@ -0,0 +1,5 @@
+fn main() {
+    for arg in std::env::args() {
+        println!("{}", arg);
+    }
+}
diff --git a/src/tools/miri/tests/pass/shims/env/args.stdout b/src/tools/miri/tests/pass/shims/env/args.stdout
new file mode 100644
index 000000000000..9564f5a1aa05
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/args.stdout
@@ -0,0 +1 @@
+args
diff --git a/src/tools/miri/tests/pass/shims/env/current_dir.rs b/src/tools/miri/tests/pass/shims/env/current_dir.rs
new file mode 100644
index 000000000000..069b462ab371
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/current_dir.rs
@@ -0,0 +1,18 @@
+//@compile-flags: -Zmiri-disable-isolation
+use std::env;
+use std::io::ErrorKind;
+
+fn main() {
+    // Test that `getcwd` is available
+    let cwd = env::current_dir().unwrap();
+    // Test that changing dir to `..` actually sets the current directory to the parent of `cwd`.
+    // The only exception here is if `cwd` is the root directory, then changing directory must
+    // keep the current directory equal to `cwd`.
+    let parent = cwd.parent().unwrap_or(&cwd);
+    // Test that `chdir` is available
+    assert!(env::set_current_dir("..").is_ok());
+    // Test that `..` goes to the parent directory
+    assert_eq!(env::current_dir().unwrap(), parent);
+    // Test that `chdir` to a non-existing directory returns a proper error
+    assert_eq!(env::set_current_dir("thisdoesnotexist").unwrap_err().kind(), ErrorKind::NotFound);
+}
diff --git a/src/tools/miri/tests/pass/shims/env/current_dir_with_isolation.rs b/src/tools/miri/tests/pass/shims/env/current_dir_with_isolation.rs
new file mode 100644
index 000000000000..9dbcfeae2d64
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/current_dir_with_isolation.rs
@@ -0,0 +1,21 @@
+//@compile-flags: -Zmiri-isolation-error=warn-nobacktrace
+//@normalize-stderr-test: "(getcwd|GetCurrentDirectoryW)" -> "$$GETCWD"
+//@normalize-stderr-test: "(chdir|SetCurrentDirectoryW)" -> "$$SETCWD"
+
+use std::env;
+use std::io::ErrorKind;
+
+fn main() {
+    // Test that current dir operations return a proper error instead
+    // of stopping the machine in isolation mode
+    assert_eq!(env::current_dir().unwrap_err().kind(), ErrorKind::PermissionDenied);
+    for _i in 0..3 {
+        // Ensure we get no repeated warnings when doing this multiple times.
+        assert_eq!(env::current_dir().unwrap_err().kind(), ErrorKind::PermissionDenied);
+    }
+
+    assert_eq!(env::set_current_dir("..").unwrap_err().kind(), ErrorKind::PermissionDenied);
+    for _i in 0..3 {
+        assert_eq!(env::set_current_dir("..").unwrap_err().kind(), ErrorKind::PermissionDenied);
+    }
+}
diff --git a/src/tools/miri/tests/pass/shims/env/current_dir_with_isolation.stderr b/src/tools/miri/tests/pass/shims/env/current_dir_with_isolation.stderr
new file mode 100644
index 000000000000..589ca65a1e47
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/current_dir_with_isolation.stderr
@@ -0,0 +1,4 @@
+warning: `$GETCWD` was made to return an error due to isolation
+
+warning: `$SETCWD` was made to return an error due to isolation
+
diff --git a/src/tools/miri/tests/pass/shims/env/current_exe.rs b/src/tools/miri/tests/pass/shims/env/current_exe.rs
new file mode 100644
index 000000000000..15ea6a52b7b6
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/current_exe.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows
+//@only-on-host: the Linux std implementation opens /proc/self/exe, which doesn't work cross-target
+//@compile-flags: -Zmiri-disable-isolation
+use std::env;
+
+fn main() {
+    // The actual value we get is a bit odd: we get the Miri binary that interprets us.
+    env::current_exe().unwrap();
+}
diff --git a/src/tools/miri/tests/pass/shims/env/home.rs b/src/tools/miri/tests/pass/shims/env/home.rs
new file mode 100644
index 000000000000..9eb9c3af569d
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/home.rs
@@ -0,0 +1,9 @@
+//@ignore-target-windows: home_dir is not supported on Windows
+//@compile-flags: -Zmiri-disable-isolation
+use std::env;
+
+fn main() {
+    env::remove_var("HOME"); // make sure we enter the interesting codepath
+    #[allow(deprecated)]
+    env::home_dir().unwrap();
+}
diff --git a/src/tools/miri/tests/pass/shims/env/var-forward.rs b/src/tools/miri/tests/pass/shims/env/var-forward.rs
new file mode 100644
index 000000000000..da7730b00f08
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/var-forward.rs
@@ -0,0 +1,5 @@
+//@compile-flags: -Zmiri-env-forward=MIRI_ENV_VAR_TEST
+
+fn main() {
+    assert_eq!(std::env::var("MIRI_ENV_VAR_TEST"), Ok("0".to_owned()));
+}
diff --git a/src/tools/miri/tests/pass/shims/env/var-without-isolation.rs b/src/tools/miri/tests/pass/shims/env/var-without-isolation.rs
new file mode 100644
index 000000000000..3d7461eecfe8
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/var-without-isolation.rs
@@ -0,0 +1,5 @@
+//@compile-flags: -Zmiri-disable-isolation
+
+fn main() {
+    assert_eq!(std::env::var("MIRI_ENV_VAR_TEST"), Ok("0".to_owned()));
+}
diff --git a/src/tools/miri/tests/pass/shims/env/var.rs b/src/tools/miri/tests/pass/shims/env/var.rs
new file mode 100644
index 000000000000..23a3724ff7fd
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/var.rs
@@ -0,0 +1,26 @@
+use std::env;
+
+fn main() {
+    // Test that miri environment is isolated when communication is disabled.
+    // (`MIRI_ENV_VAR_TEST` is set by the test harness.)
+    assert_eq!(env::var("MIRI_ENV_VAR_TEST"), Err(env::VarError::NotPresent));
+
+    // Test base state.
+    println!("{:#?}", env::vars().collect::<Vec<_>>());
+    assert_eq!(env::var("MIRI_TEST"), Err(env::VarError::NotPresent));
+
+    // Set the variable.
+    env::set_var("MIRI_TEST", "the answer");
+    assert_eq!(env::var("MIRI_TEST"), Ok("the answer".to_owned()));
+    println!("{:#?}", env::vars().collect::<Vec<_>>());
+
+    // Change the variable.
+    env::set_var("MIRI_TEST", "42");
+    assert_eq!(env::var("MIRI_TEST"), Ok("42".to_owned()));
+    println!("{:#?}", env::vars().collect::<Vec<_>>());
+
+    // Remove the variable.
+    env::remove_var("MIRI_TEST");
+    assert_eq!(env::var("MIRI_TEST"), Err(env::VarError::NotPresent));
+    println!("{:#?}", env::vars().collect::<Vec<_>>());
+}
diff --git a/src/tools/miri/tests/pass/shims/env/var.stdout b/src/tools/miri/tests/pass/shims/env/var.stdout
new file mode 100644
index 000000000000..9a8f979598eb
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/env/var.stdout
@@ -0,0 +1,14 @@
+[]
+[
+    (
+        "MIRI_TEST",
+        "the answer",
+    ),
+]
+[
+    (
+        "MIRI_TEST",
+        "42",
+    ),
+]
+[]
diff --git a/src/tools/miri/tests/pass/shims/exit.rs b/src/tools/miri/tests/pass/shims/exit.rs
new file mode 100644
index 000000000000..d93f0045377e
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/exit.rs
@@ -0,0 +1,3 @@
+fn main() {
+    std::process::exit(0)
+}
diff --git a/src/tools/miri/tests/pass/shims/sleep_long.rs b/src/tools/miri/tests/pass/shims/sleep_long.rs
new file mode 100644
index 000000000000..dd4a1843942c
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/sleep_long.rs
@@ -0,0 +1,18 @@
+//@ignore-target-windows: no threads nor sleep on Windows
+//@compile-flags: -Zmiri-ignore-leaks -Zmiri-disable-isolation
+use std::sync::{Arc, Mutex};
+use std::thread;
+use std::time::Duration;
+
+fn main() {
+    let finished = Arc::new(Mutex::new(false));
+    let t_finished = finished.clone();
+    thread::spawn(move || {
+        // Sleep very, very long.
+        thread::sleep(Duration::new(u64::MAX, 0));
+        *t_finished.lock().unwrap() = true;
+    });
+    thread::sleep(Duration::from_millis(100));
+    assert_eq!(*finished.lock().unwrap(), false);
+    // Stopping the main thread will also kill the sleeper.
+}
diff --git a/src/tools/miri/tests/pass/shims/time-with-isolation.rs b/src/tools/miri/tests/pass/shims/time-with-isolation.rs
new file mode 100644
index 000000000000..b6444319b59b
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/time-with-isolation.rs
@@ -0,0 +1,35 @@
+use std::time::{Duration, Instant};
+
+fn test_sleep() {
+    // We sleep a *long* time here -- but the clock is virtual so the test should still pass quickly.
+    let before = Instant::now();
+    std::thread::sleep(Duration::from_secs(3600));
+    let after = Instant::now();
+    assert!((after - before).as_secs() >= 3600);
+}
+
+/// Ensure that time passes even if we don't sleep (but just work).
+fn test_time_passes() {
+    // Check `Instant`.
+    let now1 = Instant::now();
+    // Do some work to make time pass.
+    for _ in 0..10 {
+        drop(vec![42]);
+    }
+    let now2 = Instant::now();
+    assert!(now2 > now1);
+    // Sanity-check the difference we got.
+    let diff = now2.duration_since(now1);
+    assert_eq!(now1 + diff, now2);
+    assert_eq!(now2 - diff, now1);
+    // The virtual clock is deterministic and I got 29us on a 64-bit Linux machine. However, this
+    // changes according to the platform so we use an interval to be safe. This should be updated
+    // if `NANOSECONDS_PER_BASIC_BLOCK` changes.
+    assert!(diff.as_micros() > 10);
+    assert!(diff.as_micros() < 40);
+}
+
+fn main() {
+    test_time_passes();
+    test_sleep();
+}
diff --git a/src/tools/miri/tests/pass/shims/time.rs b/src/tools/miri/tests/pass/shims/time.rs
new file mode 100644
index 000000000000..23b5ab57efa0
--- /dev/null
+++ b/src/tools/miri/tests/pass/shims/time.rs
@@ -0,0 +1,52 @@
+//@compile-flags: -Zmiri-disable-isolation
+
+use std::time::{Duration, Instant, SystemTime};
+
+fn duration_sanity(diff: Duration) {
+    // On my laptop, I observed times around 15-40ms. Add 10x lee-way both ways.
+    assert!(diff.as_millis() > 1);
+    assert!(diff.as_millis() < 500);
+}
+
+fn test_sleep() {
+    let before = Instant::now();
+    std::thread::sleep(Duration::from_millis(100));
+    let after = Instant::now();
+    assert!((after - before).as_millis() >= 100);
+}
+
+fn main() {
+    // Check `SystemTime`.
+    let now1 = SystemTime::now();
+    let seconds_since_epoch = now1.duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
+    let years_since_epoch = seconds_since_epoch / 3600 / 24 / 365;
+    let year = 1970 + years_since_epoch;
+    assert!(2020 <= year && year < 2100);
+    // Do some work to make time pass.
+    for _ in 0..10 {
+        drop(vec![42]);
+    }
+    let now2 = SystemTime::now();
+    assert!(now2 > now1);
+    // Sanity-check the difference we got.
+    let diff = now2.duration_since(now1).unwrap();
+    assert_eq!(now1 + diff, now2);
+    assert_eq!(now2 - diff, now1);
+    duration_sanity(diff);
+
+    // Check `Instant`.
+    let now1 = Instant::now();
+    // Do some work to make time pass.
+    for _ in 0..10 {
+        drop(vec![42]);
+    }
+    let now2 = Instant::now();
+    assert!(now2 > now1);
+    // Sanity-check the difference we got.
+    let diff = now2.duration_since(now1);
+    assert_eq!(now1 + diff, now2);
+    assert_eq!(now2 - diff, now1);
+    duration_sanity(diff);
+
+    test_sleep();
+}
diff --git a/src/tools/miri/tests/pass/simd-intrinsic-generic-elements.rs b/src/tools/miri/tests/pass/simd-intrinsic-generic-elements.rs
new file mode 100644
index 000000000000..5958357c8b7b
--- /dev/null
+++ b/src/tools/miri/tests/pass/simd-intrinsic-generic-elements.rs
@@ -0,0 +1,24 @@
+#![feature(repr_simd, platform_intrinsics)]
+
+#[repr(simd)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[allow(non_camel_case_types)]
+struct i32x2(i32, i32);
+#[repr(simd)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[allow(non_camel_case_types)]
+struct i32x4(i32, i32, i32, i32);
+#[repr(simd)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[allow(non_camel_case_types)]
+struct i32x8(i32, i32, i32, i32, i32, i32, i32, i32);
+
+fn main() {
+    let _x2 = i32x2(20, 21);
+    let _x4 = i32x4(40, 41, 42, 43);
+    let _x8 = i32x8(80, 81, 82, 83, 84, 85, 86, 87);
+
+    let _y2 = i32x2(120, 121);
+    let _y4 = i32x4(140, 141, 142, 143);
+    let _y8 = i32x8(180, 181, 182, 183, 184, 185, 186, 187);
+}
diff --git a/src/tools/miri/tests/pass/slices.rs b/src/tools/miri/tests/pass/slices.rs
new file mode 100644
index 000000000000..a56b97a5088f
--- /dev/null
+++ b/src/tools/miri/tests/pass/slices.rs
@@ -0,0 +1,274 @@
+//@compile-flags: -Zmiri-strict-provenance
+#![feature(new_uninit)]
+#![feature(slice_as_chunks)]
+#![feature(slice_partition_dedup)]
+#![feature(layout_for_ptr)]
+#![feature(strict_provenance)]
+
+use std::ptr;
+use std::slice;
+
+fn slice_of_zst() {
+    fn foo<T>(v: &[T]) -> Option<&[T]> {
+        let mut it = v.iter();
+        for _ in 0..5 {
+            it.next();
+        }
+        Some(it.as_slice())
+    }
+
+    fn foo_mut<T>(v: &mut [T]) -> Option<&mut [T]> {
+        let mut it = v.iter_mut();
+        for _ in 0..5 {
+            it.next();
+        }
+        Some(it.into_slice())
+    }
+
+    // In a slice of zero-size elements the pointer is meaningless.
+    // Ensure iteration still works even if the pointer is at the end of the address space.
+    let slice: &[()] = unsafe { slice::from_raw_parts(ptr::invalid(-5isize as usize), 10) };
+    assert_eq!(slice.len(), 10);
+    assert_eq!(slice.iter().count(), 10);
+
+    // .nth() on the iterator should also behave correctly
+    let mut it = slice.iter();
+    assert!(it.nth(5).is_some());
+    assert_eq!(it.count(), 4);
+
+    // Converting Iter to a slice should never have a null pointer
+    assert!(foo(slice).is_some());
+
+    // Test mutable iterators as well
+    let slice: &mut [()] =
+        unsafe { slice::from_raw_parts_mut(ptr::invalid_mut(-5isize as usize), 10) };
+    assert_eq!(slice.len(), 10);
+    assert_eq!(slice.iter_mut().count(), 10);
+
+    {
+        let mut it = slice.iter_mut();
+        assert!(it.nth(5).is_some());
+        assert_eq!(it.count(), 4);
+    }
+
+    assert!(foo_mut(slice).is_some())
+}
+
+fn test_iter_ref_consistency() {
+    use std::fmt::Debug;
+
+    fn test<T: Copy + Debug + PartialEq>(x: T) {
+        let v: &[T] = &[x, x, x];
+        let v_ptrs: [*const T; 3] = match v {
+            [ref v1, ref v2, ref v3] => [v1 as *const _, v2 as *const _, v3 as *const _],
+            _ => unreachable!(),
+        };
+        let len = v.len();
+
+        // nth(i)
+        for i in 0..len {
+            assert_eq!(&v[i] as *const _, v_ptrs[i]); // check the v_ptrs array, just to be sure
+            let nth = v.iter().nth(i).unwrap();
+            assert_eq!(nth as *const _, v_ptrs[i]);
+        }
+        assert_eq!(v.iter().nth(len), None, "nth(len) should return None");
+
+        // stepping through with nth(0)
+        {
+            let mut it = v.iter();
+            for i in 0..len {
+                let next = it.nth(0).unwrap();
+                assert_eq!(next as *const _, v_ptrs[i]);
+            }
+            assert_eq!(it.nth(0), None);
+        }
+
+        // next()
+        {
+            let mut it = v.iter();
+            for i in 0..len {
+                let remaining = len - i;
+                assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+                let next = it.next().unwrap();
+                assert_eq!(next as *const _, v_ptrs[i]);
+            }
+            assert_eq!(it.size_hint(), (0, Some(0)));
+            assert_eq!(it.next(), None, "The final call to next() should return None");
+        }
+
+        // next_back()
+        {
+            let mut it = v.iter();
+            for i in 0..len {
+                let remaining = len - i;
+                assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+                let prev = it.next_back().unwrap();
+                assert_eq!(prev as *const _, v_ptrs[remaining - 1]);
+            }
+            assert_eq!(it.size_hint(), (0, Some(0)));
+            assert_eq!(it.next_back(), None, "The final call to next_back() should return None");
+        }
+    }
+
+    fn test_mut<T: Copy + Debug + PartialEq>(x: T) {
+        let v: &mut [T] = &mut [x, x, x];
+        let v_ptrs: [*mut T; 3] = match v {
+            [ref v1, ref v2, ref v3] =>
+                [v1 as *const _ as *mut _, v2 as *const _ as *mut _, v3 as *const _ as *mut _],
+            _ => unreachable!(),
+        };
+        let len = v.len();
+
+        // nth(i)
+        for i in 0..len {
+            assert_eq!(&mut v[i] as *mut _, v_ptrs[i]); // check the v_ptrs array, just to be sure
+            let nth = v.iter_mut().nth(i).unwrap();
+            assert_eq!(nth as *mut _, v_ptrs[i]);
+        }
+        assert_eq!(v.iter().nth(len), None, "nth(len) should return None");
+
+        // stepping through with nth(0)
+        {
+            let mut it = v.iter();
+            for i in 0..len {
+                let next = it.nth(0).unwrap();
+                assert_eq!(next as *const _, v_ptrs[i]);
+            }
+            assert_eq!(it.nth(0), None);
+        }
+
+        // next()
+        {
+            let mut it = v.iter_mut();
+            for i in 0..len {
+                let remaining = len - i;
+                assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+                let next = it.next().unwrap();
+                assert_eq!(next as *mut _, v_ptrs[i]);
+            }
+            assert_eq!(it.size_hint(), (0, Some(0)));
+            assert_eq!(it.next(), None, "The final call to next() should return None");
+        }
+
+        // next_back()
+        {
+            let mut it = v.iter_mut();
+            for i in 0..len {
+                let remaining = len - i;
+                assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+                let prev = it.next_back().unwrap();
+                assert_eq!(prev as *mut _, v_ptrs[remaining - 1]);
+            }
+            assert_eq!(it.size_hint(), (0, Some(0)));
+            assert_eq!(it.next_back(), None, "The final call to next_back() should return None");
+        }
+    }
+
+    // Make sure iterators and slice patterns yield consistent addresses for various types,
+    // including ZSTs.
+    test(0u32);
+    test(());
+    test([0u32; 0]); // ZST with alignment > 0
+    test_mut(0u32);
+    test_mut(());
+    test_mut([0u32; 0]); // ZST with alignment > 0
+}
+
+fn uninit_slice() {
+    let mut values = Box::<[Box<u32>]>::new_uninit_slice(3);
+
+    let values = unsafe {
+        // Deferred initialization:
+        values[0].as_mut_ptr().write(Box::new(1));
+        values[1].as_mut_ptr().write(Box::new(2));
+        values[2].as_mut_ptr().write(Box::new(3));
+
+        values.assume_init()
+    };
+
+    assert_eq!(values.iter().map(|x| **x).collect::<Vec<_>>(), vec![1, 2, 3])
+}
+
+/// Regression tests for slice methods in the Rust core library where raw pointers are obtained
+/// from mutable references.
+fn test_for_invalidated_pointers() {
+    let mut buffer = [0usize; 64];
+    let len = buffer.len();
+
+    // These regression tests (indirectly) call every slice method which contains a `buffer.as_mut_ptr()`.
+    // `<[T]>::as_mut_ptr(&mut self)` takes a mutable reference (tagged Unique), which will invalidate all
+    // the other pointers that were previously derived from it according to the Stacked Borrows model.
+    // An example of where this could go wrong is a prior bug inside `<[T]>::copy_within`:
+    //
+    //      unsafe {
+    //          core::ptr::copy(self.as_ptr().add(src_start), self.as_mut_ptr().add(dest), count);
+    //      }
+    //
+    // The arguments to `core::ptr::copy` are evaluated from left to right. `self.as_ptr()` creates
+    // an immutable reference (which is tagged as `SharedReadOnly` by Stacked Borrows) to the array
+    // and derives a valid `*const` pointer from it. When jumping to the next argument,
+    // `self.as_mut_ptr()` creates a mutable reference (tagged as `Unique`) to the array, which
+    // invalidates the existing `SharedReadOnly` reference and any pointers derived from it.
+    // The invalidated `*const` pointer (the first argument to `core::ptr::copy`) is then used
+    // after the fact when `core::ptr::copy` is called, which triggers undefined behavior.
+
+    unsafe {
+        assert_eq!(0, *buffer.as_mut_ptr_range().start);
+    }
+    // Check that the pointer range is in-bounds, while we're at it
+    let range = buffer.as_mut_ptr_range();
+    unsafe {
+        assert_eq!(*range.start, *range.end.sub(len));
+    }
+
+    buffer.reverse();
+
+    // Calls `fn as_chunks_unchecked_mut` internally (requires unstable `#![feature(slice_as_chunks)]`):
+    assert_eq!(2, buffer.as_chunks_mut::<32>().0.len());
+    for chunk in buffer.as_chunks_mut::<32>().0 {
+        for elem in chunk {
+            *elem += 1;
+        }
+    }
+
+    // Calls `fn split_at_mut_unchecked` internally:
+    let split_mut = buffer.split_at_mut(32);
+    assert_eq!(split_mut.0, split_mut.1);
+
+    // Calls `fn partition_dedup_by` internally (requires unstable `#![feature(slice_partition_dedup)]`):
+    let partition_dedup = buffer.partition_dedup();
+    assert_eq!(1, partition_dedup.0.len());
+    partition_dedup.0[0] += 1;
+    for elem in partition_dedup.1 {
+        *elem += 1;
+    }
+
+    buffer.rotate_left(8);
+    buffer.rotate_right(16);
+
+    buffer.copy_from_slice(&[1usize; 64]);
+    buffer.swap_with_slice(&mut [2usize; 64]);
+
+    assert_eq!(0, unsafe { buffer.align_to_mut::<u8>().1[1] });
+
+    buffer.copy_within(1.., 0);
+}
+
+fn large_raw_slice() {
+    let size = isize::MAX as usize;
+    // Creating a raw slice of size isize::MAX and asking for its size is okay.
+    let s = std::ptr::slice_from_raw_parts(ptr::invalid::<u8>(1), size);
+    assert_eq!(size, unsafe { std::mem::size_of_val_raw(s) });
+}
+
+fn main() {
+    slice_of_zst();
+    test_iter_ref_consistency();
+    uninit_slice();
+    test_for_invalidated_pointers();
+    large_raw_slice();
+}
diff --git a/src/tools/miri/tests/pass/small_enum_size_bug.rs b/src/tools/miri/tests/pass/small_enum_size_bug.rs
new file mode 100644
index 000000000000..bb2f597444e7
--- /dev/null
+++ b/src/tools/miri/tests/pass/small_enum_size_bug.rs
@@ -0,0 +1,13 @@
+#[allow(dead_code)]
+enum E {
+    A = 1,
+    B = 2,
+    C = 3,
+}
+
+fn main() {
+    let enone = None::<E>;
+    if let Some(..) = enone {
+        panic!();
+    }
+}
diff --git a/src/tools/miri/tests/pass/specialization.rs b/src/tools/miri/tests/pass/specialization.rs
new file mode 100644
index 000000000000..428dea073eb5
--- /dev/null
+++ b/src/tools/miri/tests/pass/specialization.rs
@@ -0,0 +1,26 @@
+#![allow(incomplete_features)]
+#![feature(specialization)]
+
+trait IsUnit {
+    fn is_unit() -> bool;
+}
+
+impl<T> IsUnit for T {
+    default fn is_unit() -> bool {
+        false
+    }
+}
+
+impl IsUnit for () {
+    fn is_unit() -> bool {
+        true
+    }
+}
+
+fn specialization() -> (bool, bool) {
+    (i32::is_unit(), <()>::is_unit())
+}
+
+fn main() {
+    assert_eq!(specialization(), (false, true));
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/2phase.rs b/src/tools/miri/tests/pass/stacked-borrows/2phase.rs
new file mode 100644
index 000000000000..eb543d691e10
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/2phase.rs
@@ -0,0 +1,87 @@
+trait S: Sized {
+    fn tpb(&mut self, _s: Self) {}
+}
+
+impl S for i32 {}
+
+fn two_phase1() {
+    let mut x = 3;
+    x.tpb(x);
+}
+
+fn two_phase2() {
+    let mut v = vec![];
+    v.push(v.len());
+}
+
+fn two_phase3(b: bool) {
+    let mut x = &mut vec![];
+    let mut y = vec![];
+    x.push((
+        {
+            if b {
+                x = &mut y;
+            }
+            22
+        },
+        x.len(),
+    ));
+}
+
+#[allow(unreachable_code)]
+fn two_phase_raw() {
+    let x: &mut Vec<i32> = &mut vec![];
+    x.push({
+        // Unfortunately this does not trigger the problem of creating a
+        // raw ponter from a pointer that had a two-phase borrow derived from
+        // it because of the implicit &mut reborrow.
+        let raw = x as *mut _;
+        unsafe {
+            *raw = vec![1];
+        }
+        return;
+    });
+}
+
+fn two_phase_overlapping1() {
+    let mut x = vec![];
+    let p = &x;
+    x.push(p.len());
+}
+
+fn two_phase_overlapping2() {
+    use std::ops::AddAssign;
+    let mut x = 1;
+    let l = &x;
+    x.add_assign(x + *l);
+}
+
+fn with_interior_mutability() {
+    use std::cell::Cell;
+
+    trait Thing: Sized {
+        fn do_the_thing(&mut self, _s: i32) {}
+    }
+
+    impl<T> Thing for Cell<T> {}
+
+    let mut x = Cell::new(1);
+    let l = &x;
+
+    x.do_the_thing({
+        x.set(3);
+        l.set(4);
+        x.get() + l.get()
+    });
+}
+
+fn main() {
+    two_phase1();
+    two_phase2();
+    two_phase3(false);
+    two_phase3(true);
+    two_phase_raw();
+    with_interior_mutability();
+    two_phase_overlapping1();
+    two_phase_overlapping2();
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/generators-self-referential.rs b/src/tools/miri/tests/pass/stacked-borrows/generators-self-referential.rs
new file mode 100644
index 000000000000..b71912882dd2
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/generators-self-referential.rs
@@ -0,0 +1,34 @@
+// See https://github.com/rust-lang/unsafe-code-guidelines/issues/148:
+// this fails when Stacked Borrows is strictly applied even to `!Unpin` types.
+#![feature(generators, generator_trait)]
+
+use std::{
+    ops::{Generator, GeneratorState},
+    pin::Pin,
+};
+
+fn firstn() -> impl Generator<Yield = u64, Return = ()> {
+    static move || {
+        let mut num = 0;
+        let num = &mut num;
+
+        yield *num;
+        *num += 1; // would fail here
+
+        yield *num;
+        *num += 1;
+
+        yield *num;
+        *num += 1;
+    }
+}
+
+fn main() {
+    let mut generator_iterator = firstn();
+    let mut pin = unsafe { Pin::new_unchecked(&mut generator_iterator) };
+    let mut sum = 0;
+    while let GeneratorState::Yielded(x) = pin.as_mut().resume(()) {
+        sum += x;
+    }
+    assert_eq!(sum, 3);
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/int-to-ptr.rs b/src/tools/miri/tests/pass/stacked-borrows/int-to-ptr.rs
new file mode 100644
index 000000000000..c3e30627a7ce
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/int-to-ptr.rs
@@ -0,0 +1,83 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#![feature(strict_provenance)]
+use std::ptr;
+
+// Just to make sure that casting a ref to raw, to int and back to raw
+// and only then using it works. This rules out ideas like "do escape-to-raw lazily";
+// after casting to int and back, we lost the tag that could have let us do that.
+fn ref_raw_int_raw() {
+    let mut x = 3;
+    let xref = &mut x;
+    let xraw = xref as *mut i32 as usize as *mut i32;
+    assert_eq!(unsafe { *xraw }, 3);
+}
+
+/// Ensure that we do not just pick the topmost possible item on int2ptr casts.
+fn example(variant: bool) {
+    unsafe {
+        fn not_so_innocent(x: &mut u32) -> usize {
+            let x_raw4 = x as *mut u32;
+            x_raw4.expose_addr()
+        }
+
+        let mut c = 42u32;
+
+        let x_unique1 = &mut c;
+        // [..., Unique(1)]
+
+        let x_raw2 = x_unique1 as *mut u32;
+        let x_raw2_addr = x_raw2.expose_addr();
+        // [..., Unique(1), SharedRW(2)]
+
+        let x_unique3 = &mut *x_raw2;
+        // [.., Unique(1), SharedRW(2), Unique(3)]
+
+        assert_eq!(not_so_innocent(x_unique3), x_raw2_addr);
+        // [.., Unique(1), SharedRW(2), Unique(3), ..., SharedRW(4)]
+
+        // Do an int2ptr cast. This can pick tag 2 or 4 (the two previously exposed tags).
+        // 4 is the "obvious" choice (topmost tag, what we used to do with untagged pointers).
+        // And indeed if `variant == true` it is the only possible choice.
+        // But if `variant == false` then 2 is the only possible choice!
+        let x_wildcard = ptr::from_exposed_addr_mut::<i32>(x_raw2_addr);
+
+        if variant {
+            // If we picked 2, this will invalidate 3.
+            *x_wildcard = 10;
+            // Now we use 3. Only possible if above we picked 4.
+            *x_unique3 = 12;
+        } else {
+            // This invalidates tag 4.
+            *x_unique3 = 10;
+            // Now try to write with the "guessed" tag; it must be 2.
+            *x_wildcard = 12;
+        }
+    }
+}
+
+fn test() {
+    unsafe {
+        let root = &mut 42;
+        let root_raw = root as *mut i32;
+        let addr1 = root_raw as usize;
+        let child = &mut *root_raw;
+        let child_raw = child as *mut i32;
+        let addr2 = child_raw as usize;
+        assert_eq!(addr1, addr2);
+        // First use child.
+        *(addr2 as *mut i32) -= 2; // picks child_raw
+        *child -= 2;
+        // Then use root.
+        *(addr1 as *mut i32) += 2; // picks root_raw
+        *root += 2;
+        // Value should be unchanged.
+        assert_eq!(*root, 42);
+    }
+}
+
+fn main() {
+    ref_raw_int_raw();
+    example(false);
+    example(true);
+    test();
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/interior_mutability.rs b/src/tools/miri/tests/pass/stacked-borrows/interior_mutability.rs
new file mode 100644
index 000000000000..c6373a7eaf13
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/interior_mutability.rs
@@ -0,0 +1,175 @@
+//@compile-flags: -Zmiri-retag-fields
+use std::cell::{Cell, Ref, RefCell, RefMut, UnsafeCell};
+use std::mem::{self, MaybeUninit};
+
+fn main() {
+    aliasing_mut_and_shr();
+    aliasing_frz_and_shr();
+    into_interior_mutability();
+    unsafe_cell_2phase();
+    unsafe_cell_deallocate();
+    unsafe_cell_invalidate();
+    refcell_basic();
+    ref_protector();
+    ref_mut_protector();
+    rust_issue_68303();
+}
+
+fn aliasing_mut_and_shr() {
+    fn inner(rc: &RefCell<i32>, aliasing: &mut i32) {
+        *aliasing += 4;
+        let _escape_to_raw = rc as *const _;
+        *aliasing += 4;
+        let _shr = &*rc;
+        *aliasing += 4;
+        // also turning this into a frozen ref now must work
+        let aliasing = &*aliasing;
+        let _val = *aliasing;
+        let _escape_to_raw = rc as *const _; // this must NOT unfreeze
+        let _val = *aliasing;
+        let _shr = &*rc; // this must NOT unfreeze
+        let _val = *aliasing;
+    }
+
+    let rc = RefCell::new(23);
+    let mut bmut = rc.borrow_mut();
+    inner(&rc, &mut *bmut);
+    drop(bmut);
+    assert_eq!(*rc.borrow(), 23 + 12);
+}
+
+fn aliasing_frz_and_shr() {
+    fn inner(rc: &RefCell<i32>, aliasing: &i32) {
+        let _val = *aliasing;
+        let _escape_to_raw = rc as *const _; // this must NOT unfreeze
+        let _val = *aliasing;
+        let _shr = &*rc; // this must NOT unfreeze
+        let _val = *aliasing;
+    }
+
+    let rc = RefCell::new(23);
+    let bshr = rc.borrow();
+    inner(&rc, &*bshr);
+    assert_eq!(*rc.borrow(), 23);
+}
+
+// Getting a pointer into a union with interior mutability used to be tricky
+// business (https://github.com/rust-lang/miri/issues/615), but it should work
+// now.
+fn into_interior_mutability() {
+    let mut x: MaybeUninit<(Cell<u32>, u32)> = MaybeUninit::uninit();
+    x.as_ptr();
+    x.write((Cell::new(0), 1));
+    let ptr = unsafe { x.assume_init_ref() };
+    assert_eq!(ptr.1, 1);
+}
+
+// Two-phase borrows of the pointer returned by UnsafeCell::get() should not
+// invalidate aliases.
+fn unsafe_cell_2phase() {
+    unsafe {
+        let x = &UnsafeCell::new(vec![]);
+        let x2 = &*x;
+        (*x.get()).push(0);
+        let _val = (*x2.get()).get(0);
+    }
+}
+
+/// Make sure we can deallocate an UnsafeCell that was passed to an active fn call.
+/// (This is the fix for https://github.com/rust-lang/rust/issues/55005.)
+fn unsafe_cell_deallocate() {
+    fn f(x: &UnsafeCell<i32>) {
+        let b: Box<i32> = unsafe { Box::from_raw(x as *const _ as *mut i32) };
+        drop(b)
+    }
+
+    let b = Box::new(0i32);
+    f(unsafe { mem::transmute(Box::into_raw(b)) });
+}
+
+/// As a side-effect of the above, we also allow this -- at least for now.
+fn unsafe_cell_invalidate() {
+    fn f(_x: &UnsafeCell<i32>, y: *mut i32) {
+        // Writing to y invalidates x, but that is okay.
+        unsafe {
+            *y += 1;
+        }
+    }
+
+    let mut x = 0i32;
+    let raw1 = &mut x as *mut _;
+    let ref1 = unsafe { &mut *raw1 };
+    let raw2 = ref1 as *mut _;
+    // Now the borrow stack is: raw1, ref2, raw2.
+    // So using raw1 invalidates raw2.
+    f(unsafe { mem::transmute(raw2) }, raw1);
+}
+
+fn refcell_basic() {
+    let c = RefCell::new(42);
+    {
+        let s1 = c.borrow();
+        let _x: i32 = *s1;
+        let s2 = c.borrow();
+        let _x: i32 = *s1;
+        let _y: i32 = *s2;
+        let _x: i32 = *s1;
+        let _y: i32 = *s2;
+    }
+    {
+        let mut m = c.borrow_mut();
+        let _z: i32 = *m;
+        {
+            let s: &i32 = &*m;
+            let _x = *s;
+        }
+        *m = 23;
+        let _z: i32 = *m;
+    }
+    {
+        let s1 = c.borrow();
+        let _x: i32 = *s1;
+        let s2 = c.borrow();
+        let _x: i32 = *s1;
+        let _y: i32 = *s2;
+        let _x: i32 = *s1;
+        let _y: i32 = *s2;
+    }
+}
+
+// Adding a Stacked Borrows protector for `Ref` would break this
+fn ref_protector() {
+    fn break_it(rc: &RefCell<i32>, r: Ref<'_, i32>) {
+        // `r` has a shared reference, it is passed in as argument and hence
+        // a protector is added that marks this memory as read-only for the entire
+        // duration of this function.
+        drop(r);
+        // *oops* here we can mutate that memory.
+        *rc.borrow_mut() = 2;
+    }
+
+    let rc = RefCell::new(0);
+    break_it(&rc, rc.borrow())
+}
+
+fn ref_mut_protector() {
+    fn break_it(rc: &RefCell<i32>, r: RefMut<'_, i32>) {
+        // `r` has a shared reference, it is passed in as argument and hence
+        // a protector is added that marks this memory as inaccessible for the entire
+        // duration of this function
+        drop(r);
+        // *oops* here we can mutate that memory.
+        *rc.borrow_mut() = 2;
+    }
+
+    let rc = RefCell::new(0);
+    break_it(&rc, rc.borrow_mut())
+}
+
+/// Make sure we do not have bad enum layout optimizations.
+fn rust_issue_68303() {
+    let optional = Some(RefCell::new(false));
+    let mut handle = optional.as_ref().unwrap().borrow_mut();
+    assert!(optional.is_some());
+    *handle = true;
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.rs b/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.rs
new file mode 100644
index 000000000000..469122095e51
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.rs
@@ -0,0 +1,17 @@
+use std::cell::Cell;
+
+fn main() {
+    unsafe {
+        let root0 = Cell::new(42);
+        let wildcard = &root0 as *const Cell<i32> as usize as *const Cell<i32>;
+        // empty the stack to unknown (via SRW reborrow from wildcard)
+        let _ref0 = &*wildcard;
+        // Do a non-SRW reborrow from wildcard to start building up a stack again.
+        // Now new refs start being inserted at idx 0, pushing the unique_range up.
+        let _refn = &*&*&*&*&*(wildcard.cast::<i32>());
+        // empty the stack again, but this time with unique_range.start sitting at some high index.
+        let _ref0 = &*wildcard;
+        // and do a read which tries to clear the uniques
+        wildcard.cast::<i32>().read();
+    }
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr b/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr
new file mode 100644
index 000000000000..f3ba052ae513
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr
@@ -0,0 +1,15 @@
+warning: integer-to-pointer cast
+  --> $DIR/issue-miri-2389.rs:LL:CC
+   |
+LL |         let wildcard = &root0 as *const Cell<i32> as usize as *const Cell<i32>;
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast
+   |
+   = help: This program is using integer-to-pointer casts or (equivalently) `ptr::from_exposed_addr`,
+   = help: which means that Miri might miss pointer bugs in this program.
+   = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.from_exposed_addr.html for more details on that operation.
+   = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead.
+   = help: You can then pass the `-Zmiri-strict-provenance` flag to Miri, to ensure you are not relying on `from_exposed_addr` semantics.
+   = help: Alternatively, the `-Zmiri-permissive-provenance` flag disables this warning.
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/issue-miri-2389.rs:LL:CC
+
diff --git a/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs b/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs
new file mode 100644
index 000000000000..ef6eb346c17b
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs
@@ -0,0 +1,221 @@
+//@compile-flags: -Zmiri-retag-fields
+#![feature(allocator_api)]
+use std::ptr;
+
+// Test various stacked-borrows-related things.
+fn main() {
+    read_does_not_invalidate1();
+    read_does_not_invalidate2();
+    mut_raw_then_mut_shr();
+    mut_shr_then_mut_raw();
+    mut_raw_mut();
+    partially_invalidate_mut();
+    drop_after_sharing();
+    direct_mut_to_const_raw();
+    two_raw();
+    shr_and_raw();
+    disjoint_mutable_subborrows();
+    raw_ref_to_part();
+    array_casts();
+    mut_below_shr();
+    wide_raw_ptr_in_tuple();
+}
+
+// Make sure that reading from an `&mut` does, like reborrowing to `&`,
+// NOT invalidate other reborrows.
+fn read_does_not_invalidate1() {
+    fn foo(x: &mut (i32, i32)) -> &i32 {
+        let xraw = x as *mut (i32, i32);
+        let ret = unsafe { &(*xraw).1 };
+        let _val = x.1; // we just read, this does NOT invalidate the reborrows.
+        ret
+    }
+    assert_eq!(*foo(&mut (1, 2)), 2);
+}
+// Same as above, but this time we first create a raw, then read from `&mut`
+// and then freeze from the raw.
+fn read_does_not_invalidate2() {
+    fn foo(x: &mut (i32, i32)) -> &i32 {
+        let xraw = x as *mut (i32, i32);
+        let _val = x.1; // we just read, this does NOT invalidate the raw reborrow.
+        let ret = unsafe { &(*xraw).1 };
+        ret
+    }
+    assert_eq!(*foo(&mut (1, 2)), 2);
+}
+
+// Escape a mut to raw, then share the same mut and use the share, then the raw.
+// That should work.
+fn mut_raw_then_mut_shr() {
+    let mut x = 2;
+    let xref = &mut x;
+    let xraw = &mut *xref as *mut _;
+    let xshr = &*xref;
+    assert_eq!(*xshr, 2);
+    unsafe {
+        *xraw = 4;
+    }
+    assert_eq!(x, 4);
+}
+
+// Create first a shared reference and then a raw pointer from a `&mut`
+// should permit mutation through that raw pointer.
+fn mut_shr_then_mut_raw() {
+    let xref = &mut 2;
+    let _xshr = &*xref;
+    let xraw = xref as *mut _;
+    unsafe {
+        *xraw = 3;
+    }
+    assert_eq!(*xref, 3);
+}
+
+// Ensure that if we derive from a mut a raw, and then from that a mut,
+// and then read through the original mut, that does not invalidate the raw.
+// This shows that the read-exception for `&mut` applies even if the `Shr` item
+// on the stack is not at the top.
+fn mut_raw_mut() {
+    let mut x = 2;
+    {
+        let xref1 = &mut x;
+        let xraw = xref1 as *mut _;
+        let _xref2 = unsafe { &mut *xraw };
+        let _val = *xref1;
+        unsafe {
+            *xraw = 4;
+        }
+        // we can now use both xraw and xref1, for reading
+        assert_eq!(*xref1, 4);
+        assert_eq!(unsafe { *xraw }, 4);
+        assert_eq!(*xref1, 4);
+        assert_eq!(unsafe { *xraw }, 4);
+        // we cannot use xref2; see `compile-fail/stacked-borows/illegal_read4.rs`
+    }
+    assert_eq!(x, 4);
+}
+
+fn partially_invalidate_mut() {
+    let data = &mut (0u8, 0u8);
+    let reborrow = &mut *data as *mut (u8, u8);
+    let shard = unsafe { &mut (*reborrow).0 };
+    data.1 += 1; // the deref overlaps with `shard`, but that is ok; the access does not overlap.
+    *shard += 1; // so we can still use `shard`.
+    assert_eq!(*data, (1, 1));
+}
+
+// Make sure that we can handle the situation where a loaction is frozen when being dropped.
+fn drop_after_sharing() {
+    let x = String::from("hello!");
+    let _len = x.len();
+}
+
+// Make sure that coercing &mut T to *const T produces a writeable pointer.
+fn direct_mut_to_const_raw() {
+    // TODO: This is currently disabled, waiting on a decision on <https://github.com/rust-lang/rust/issues/56604>
+    /*let x = &mut 0;
+    let y: *const i32 = x;
+    unsafe { *(y as *mut i32) = 1; }
+    assert_eq!(*x, 1);
+    */
+}
+
+// Make sure that we can create two raw pointers from a mutable reference and use them both.
+fn two_raw() {
+    unsafe {
+        let x = &mut 0;
+        let y1 = x as *mut _;
+        let y2 = x as *mut _;
+        *y1 += 2;
+        *y2 += 1;
+    }
+}
+
+// Make sure that creating a *mut does not invalidate existing shared references.
+fn shr_and_raw() {
+    unsafe {
+        use std::mem;
+        let x = &mut 0;
+        let y1: &i32 = mem::transmute(&*x); // launder lifetimes
+        let y2 = x as *mut _;
+        let _val = *y1;
+        *y2 += 1;
+    }
+}
+
+fn disjoint_mutable_subborrows() {
+    struct Foo {
+        a: String,
+        b: Vec<u32>,
+    }
+
+    unsafe fn borrow_field_a<'a>(this: *mut Foo) -> &'a mut String {
+        &mut (*this).a
+    }
+
+    unsafe fn borrow_field_b<'a>(this: *mut Foo) -> &'a mut Vec<u32> {
+        &mut (*this).b
+    }
+
+    let mut foo = Foo { a: "hello".into(), b: vec![0, 1, 2] };
+
+    let ptr = &mut foo as *mut Foo;
+
+    let a = unsafe { borrow_field_a(ptr) };
+    let b = unsafe { borrow_field_b(ptr) };
+    b.push(4);
+    a.push_str(" world");
+    eprintln!("{:?} {:?}", a, b);
+}
+
+fn raw_ref_to_part() {
+    struct Part {
+        _lame: i32,
+    }
+
+    #[repr(C)]
+    struct Whole {
+        part: Part,
+        extra: i32,
+    }
+
+    let it = Box::new(Whole { part: Part { _lame: 0 }, extra: 42 });
+    let whole = ptr::addr_of_mut!(*Box::leak(it));
+    let part = unsafe { ptr::addr_of_mut!((*whole).part) };
+    let typed = unsafe { &mut *(part as *mut Whole) };
+    assert!(typed.extra == 42);
+    drop(unsafe { Box::from_raw(whole) });
+}
+
+/// When casting an array reference to a raw element ptr, that should cover the whole array.
+fn array_casts() {
+    let mut x: [usize; 2] = [0, 0];
+    let p = &mut x as *mut usize;
+    unsafe {
+        *p.add(1) = 1;
+    }
+
+    let x: [usize; 2] = [0, 1];
+    let p = &x as *const usize;
+    assert_eq!(unsafe { *p.add(1) }, 1);
+}
+
+/// Transmuting &&i32 to &&mut i32 is fine.
+fn mut_below_shr() {
+    let x = 0;
+    let y = &x;
+    let p = unsafe { core::mem::transmute::<&&i32, &&mut i32>(&y) };
+    let r = &**p;
+    let _val = *r;
+}
+
+fn wide_raw_ptr_in_tuple() {
+    let mut x: Box<dyn std::any::Any> = Box::new("ouch");
+    let r = &mut *x as *mut dyn std::any::Any;
+    // This triggers the visitor-based recursive retagging. It is *not* supposed to retag raw
+    // pointers, but then the visitor might recurse into the "fields" of a wide raw pointer and
+    // finds a reference (to a vtable) there that it wants to retag... and that would be Wrong.
+    let pair = (r, &0);
+    let r = unsafe { &mut *pair.0 };
+    // Make sure the fn ptr part of the vtable is still fine.
+    r.type_id();
+}
diff --git a/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.stderr b/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.stderr
new file mode 100644
index 000000000000..8ee4e25dbef8
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.stderr
@@ -0,0 +1 @@
+"hello world" [0, 1, 2, 4]
diff --git a/src/tools/miri/tests/pass/stacked-borrows/zst-field-retagging-terminates.rs b/src/tools/miri/tests/pass/stacked-borrows/zst-field-retagging-terminates.rs
new file mode 100644
index 000000000000..ce3c8b7d5f1a
--- /dev/null
+++ b/src/tools/miri/tests/pass/stacked-borrows/zst-field-retagging-terminates.rs
@@ -0,0 +1,6 @@
+//@compile-flags: -Zmiri-retag-fields
+// Checks that the test does not run forever (which relies on a fast path).
+fn main() {
+    let array = [(); usize::MAX];
+    drop(array); // Pass the array to a function, retagging its fields
+}
diff --git a/src/tools/miri/tests/pass/start.rs b/src/tools/miri/tests/pass/start.rs
new file mode 100644
index 000000000000..f25d62fa8c33
--- /dev/null
+++ b/src/tools/miri/tests/pass/start.rs
@@ -0,0 +1,8 @@
+#![feature(start)]
+
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
+    println!("Hello from start!");
+
+    0
+}
diff --git a/src/tools/miri/tests/pass/start.stdout b/src/tools/miri/tests/pass/start.stdout
new file mode 100644
index 000000000000..d7f627d237c3
--- /dev/null
+++ b/src/tools/miri/tests/pass/start.stdout
@@ -0,0 +1 @@
+Hello from start!
diff --git a/src/tools/miri/tests/pass/static_memory_modification.rs b/src/tools/miri/tests/pass/static_memory_modification.rs
new file mode 100644
index 000000000000..84a524b1ed16
--- /dev/null
+++ b/src/tools/miri/tests/pass/static_memory_modification.rs
@@ -0,0 +1,14 @@
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+static mut X: usize = 5;
+static Y: AtomicUsize = AtomicUsize::new(5);
+
+fn main() {
+    unsafe {
+        X = 6;
+        assert_eq!(X, 6);
+    }
+
+    Y.store(6, Ordering::Relaxed);
+    assert_eq!(Y.load(Ordering::Relaxed), 6);
+}
diff --git a/src/tools/miri/tests/pass/static_mut.rs b/src/tools/miri/tests/pass/static_mut.rs
new file mode 100644
index 000000000000..218b02525bd5
--- /dev/null
+++ b/src/tools/miri/tests/pass/static_mut.rs
@@ -0,0 +1,16 @@
+static mut FOO: i32 = 42;
+static BAR: Foo = Foo(unsafe { &FOO as *const _ });
+
+#[allow(dead_code)]
+struct Foo(*const i32);
+
+unsafe impl Sync for Foo {}
+
+fn main() {
+    unsafe {
+        assert_eq!(*BAR.0, 42);
+        FOO = 5;
+        assert_eq!(FOO, 5);
+        assert_eq!(*BAR.0, 5);
+    }
+}
diff --git a/src/tools/miri/tests/pass/strings.rs b/src/tools/miri/tests/pass/strings.rs
new file mode 100644
index 000000000000..5e2d2e9b5b5c
--- /dev/null
+++ b/src/tools/miri/tests/pass/strings.rs
@@ -0,0 +1,63 @@
+//@compile-flags: -Zmiri-strict-provenance
+
+fn empty() -> &'static str {
+    ""
+}
+
+fn hello() -> &'static str {
+    "Hello, world!"
+}
+
+fn hello_bytes() -> &'static [u8; 13] {
+    b"Hello, world!"
+}
+
+fn hello_bytes_fat() -> &'static [u8] {
+    b"Hello, world!"
+}
+
+fn fat_pointer_on_32_bit() {
+    Some(5).expect("foo");
+}
+
+fn str_indexing() {
+    let mut x = "Hello".to_string();
+    let _v = &mut x[..3]; // Test IndexMut on String.
+}
+
+fn unique_aliasing() {
+    // This is a regression test for the aliasing rules of a `Unique<T>` pointer.
+    // At the time of writing this test case, Miri does not treat `Unique<T>`
+    // pointers as a special case, these are treated like any other raw pointer.
+    // However, there are existing Github issues which may lead to `Unique<T>`
+    // becoming a special case through asserting unique ownership over the pointee:
+    // - https://github.com/rust-lang/unsafe-code-guidelines/issues/258
+    // - https://github.com/rust-lang/unsafe-code-guidelines/issues/262
+    // Below, the calls to `String::remove` and `String::insert[_str]` follow
+    // code paths that would trigger undefined behavior in case `Unique<T>`
+    // would ever assert semantic ownership over the pointee. Internally,
+    // these methods call `self.vec.as_ptr()` and `self.vec.as_mut_ptr()` on
+    // the vector of bytes that are backing the `String`. That `Vec<u8>` holds a
+    // `Unique<u8>` internally. The second call to `Vec::as_mut_ptr(&mut self)`
+    // would then invalidate the pointers derived from `Vec::as_ptr(&self)`.
+    // Note that as long as `Unique<T>` is treated like any other raw pointer,
+    // this test case should pass. It is merely here as a canary test for
+    // potential future undefined behavior.
+    let mut x = String::from("Hello");
+    assert_eq!(x.remove(0), 'H');
+    x.insert(0, 'H');
+    assert_eq!(x, "Hello");
+    x.insert_str(x.len(), ", world!");
+    assert_eq!(x, "Hello, world!");
+}
+
+fn main() {
+    assert_eq!(empty(), "");
+    assert_eq!(hello(), "Hello, world!");
+    assert_eq!(hello_bytes(), b"Hello, world!");
+    assert_eq!(hello_bytes_fat(), b"Hello, world!");
+
+    fat_pointer_on_32_bit(); // Should run without crashing.
+    str_indexing();
+    unique_aliasing();
+}
diff --git a/src/tools/miri/tests/pass/subslice_array.rs b/src/tools/miri/tests/pass/subslice_array.rs
new file mode 100644
index 000000000000..9b6b12d748ad
--- /dev/null
+++ b/src/tools/miri/tests/pass/subslice_array.rs
@@ -0,0 +1,11 @@
+fn bar(a: &'static str, b: &'static str) -> [&'static str; 4] {
+    [a, b, b, a]
+}
+
+fn main() {
+    let out = bar("baz", "foo");
+    let [a, xs @ .., d] = out;
+    assert_eq!(a, "baz");
+    assert_eq!(xs, ["foo", "foo"]);
+    assert_eq!(d, "baz");
+}
diff --git a/src/tools/miri/tests/pass/sums.rs b/src/tools/miri/tests/pass/sums.rs
new file mode 100644
index 000000000000..3256d4c65116
--- /dev/null
+++ b/src/tools/miri/tests/pass/sums.rs
@@ -0,0 +1,61 @@
+#[derive(Debug, PartialEq)]
+enum Unit {
+    Unit(()), // Force non-C-enum representation.
+}
+
+fn return_unit() -> Unit {
+    Unit::Unit(())
+}
+
+#[derive(Debug, PartialEq)]
+enum MyBool {
+    False(()), // Force non-C-enum representation.
+    True(()),
+}
+
+fn return_true() -> MyBool {
+    MyBool::True(())
+}
+
+fn return_false() -> MyBool {
+    MyBool::False(())
+}
+
+fn return_none() -> Option<i64> {
+    None
+}
+
+fn return_some() -> Option<i64> {
+    Some(42)
+}
+
+fn match_opt_none() -> i8 {
+    let x = None;
+    match x {
+        Some(data) => data,
+        None => 42,
+    }
+}
+
+fn match_opt_some() -> i8 {
+    let x = Some(13);
+    match x {
+        Some(data) => data,
+        None => 20,
+    }
+}
+
+fn two_nones() -> (Option<i16>, Option<i16>) {
+    (None, None)
+}
+
+fn main() {
+    assert_eq!(two_nones(), (None, None));
+    assert_eq!(match_opt_some(), 13);
+    assert_eq!(match_opt_none(), 42);
+    assert_eq!(return_some(), Some(42));
+    assert_eq!(return_none(), None);
+    assert_eq!(return_false(), MyBool::False(()));
+    assert_eq!(return_true(), MyBool::True(()));
+    assert_eq!(return_unit(), Unit::Unit(()));
+}
diff --git a/src/tools/miri/tests/pass/tag-align-dyn-u64.rs b/src/tools/miri/tests/pass/tag-align-dyn-u64.rs
new file mode 100644
index 000000000000..72211a8d3f3a
--- /dev/null
+++ b/src/tools/miri/tests/pass/tag-align-dyn-u64.rs
@@ -0,0 +1,37 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::mem;
+
+enum Tag<A> {
+    Tag2(A),
+}
+
+#[allow(dead_code)]
+struct Rec {
+    c8: u8,
+    t: Tag<u64>,
+}
+
+fn mk_rec() -> Rec {
+    return Rec { c8: 0, t: Tag::Tag2(0) };
+}
+
+fn is_u64_aligned(u: &Tag<u64>) -> bool {
+    let p: *const () = unsafe { mem::transmute(u) };
+    let p = p as usize;
+    let u64_align = std::mem::align_of::<u64>();
+    return (p & (u64_align - 1)) == 0;
+}
+
+pub fn main() {
+    let x = mk_rec();
+    assert!(is_u64_aligned(&x.t));
+}
diff --git a/src/tools/miri/tests/pass/threadleak_ignored.rs b/src/tools/miri/tests/pass/threadleak_ignored.rs
new file mode 100644
index 000000000000..99bac7aa42a8
--- /dev/null
+++ b/src/tools/miri/tests/pass/threadleak_ignored.rs
@@ -0,0 +1,38 @@
+//@ignore-target-windows: Channels on Windows are not supported yet.
+// FIXME: disallow preemption to work around https://github.com/rust-lang/rust/issues/55005
+//@compile-flags: -Zmiri-ignore-leaks -Zmiri-preemption-rate=0
+
+//! Test that leaking threads works, and that their destructors are not executed.
+
+use std::cell::RefCell;
+
+struct LoudDrop(i32);
+impl Drop for LoudDrop {
+    fn drop(&mut self) {
+        eprintln!("Dropping {}", self.0);
+    }
+}
+
+thread_local! {
+    static X: RefCell<Option<LoudDrop>> = RefCell::new(None);
+}
+
+fn main() {
+    X.with(|x| *x.borrow_mut() = Some(LoudDrop(0)));
+
+    // Set up a channel so that we can learn when the other thread initialized `X`
+    // (so that we are sure there is something to drop).
+    let (send, recv) = std::sync::mpsc::channel::<()>();
+
+    let _detached = std::thread::spawn(move || {
+        X.with(|x| *x.borrow_mut() = Some(LoudDrop(1)));
+        send.send(()).unwrap();
+        std::thread::yield_now();
+        loop {}
+    });
+
+    std::thread::yield_now();
+
+    // Wait until child thread has initialized its `X`.
+    let () = recv.recv().unwrap();
+}
diff --git a/src/tools/miri/tests/pass/threadleak_ignored.stderr b/src/tools/miri/tests/pass/threadleak_ignored.stderr
new file mode 100644
index 000000000000..7557f49c7584
--- /dev/null
+++ b/src/tools/miri/tests/pass/threadleak_ignored.stderr
@@ -0,0 +1 @@
+Dropping 0
diff --git a/src/tools/miri/tests/pass/too-large-primval-write-problem.rs b/src/tools/miri/tests/pass/too-large-primval-write-problem.rs
new file mode 100644
index 000000000000..f4c418bd78a9
--- /dev/null
+++ b/src/tools/miri/tests/pass/too-large-primval-write-problem.rs
@@ -0,0 +1,23 @@
+// `PrimVal`s in Miri are represented with 8 bytes (u64) and at the time of writing, the `-x`
+// will sign extend into the entire 8 bytes. Then, if you tried to write the `-x` into
+// something smaller than 8 bytes, like a 4 byte pointer, it would crash in byteorder crate
+// code that assumed only the low 4 bytes would be set. Actually, we were masking properly for
+// everything except pointers before I fixed it, so this was probably impossible to reproduce on
+// 64-bit.
+//
+// This is just intended as a regression test to make sure we don't reintroduce this problem.
+
+#[cfg(target_pointer_width = "32")]
+fn main() {
+    use std::mem::transmute;
+
+    // Make the weird PrimVal.
+    let x = 1i32;
+    let bad = unsafe { transmute::<i32, *const u8>(-x) };
+
+    // Force it through the Memory::write_primval code.
+    drop(Box::new(bad));
+}
+
+#[cfg(not(target_pointer_width = "32"))]
+fn main() {}
diff --git a/src/tools/miri/tests/pass/track-alloc-1.rs b/src/tools/miri/tests/pass/track-alloc-1.rs
new file mode 100644
index 000000000000..427c800dc51d
--- /dev/null
+++ b/src/tools/miri/tests/pass/track-alloc-1.rs
@@ -0,0 +1,6 @@
+// Ensure that tracking early allocations doesn't ICE Miri.
+// Early allocations are probably part of the runtime and therefore uninteresting, but they
+// shouldn't cause a crash.
+//@compile-flags: -Zmiri-track-alloc-id=1
+//@normalize-stderr-test: "[48] bytes" -> "SIZE bytes"
+fn main() {}
diff --git a/src/tools/miri/tests/pass/track-alloc-1.stderr b/src/tools/miri/tests/pass/track-alloc-1.stderr
new file mode 100644
index 000000000000..7206edbb7010
--- /dev/null
+++ b/src/tools/miri/tests/pass/track-alloc-1.stderr
@@ -0,0 +1,5 @@
+note: tracking was triggered
+   |
+   = note: created extern static allocation of SIZE bytes (alignment ALIGN bytes) with id 1
+   = note: (no span available)
+
diff --git a/src/tools/miri/tests/pass/track-caller-attribute.rs b/src/tools/miri/tests/pass/track-caller-attribute.rs
new file mode 100644
index 000000000000..6694764a234d
--- /dev/null
+++ b/src/tools/miri/tests/pass/track-caller-attribute.rs
@@ -0,0 +1,130 @@
+#![feature(core_intrinsics)]
+
+use std::panic::Location;
+
+#[track_caller]
+fn tracked() -> &'static Location<'static> {
+    Location::caller() // most importantly, we never get line 7
+}
+
+fn nested_intrinsic() -> &'static Location<'static> {
+    Location::caller()
+}
+
+fn nested_tracked() -> &'static Location<'static> {
+    tracked()
+}
+
+macro_rules! caller_location_from_macro {
+    () => {
+        core::panic::Location::caller()
+    };
+}
+
+fn test_fn_ptr() {
+    fn pass_to_ptr_call<T>(f: fn(T), x: T) {
+        f(x);
+    }
+
+    #[track_caller]
+    fn tracked_unit(_: ()) {
+        let expected_line = line!() - 1;
+        let location = std::panic::Location::caller();
+        assert_eq!(location.file(), file!());
+        assert_eq!(location.line(), expected_line, "call shims report location as fn definition");
+    }
+
+    pass_to_ptr_call(tracked_unit, ());
+}
+
+fn test_trait_obj() {
+    trait Tracked {
+        #[track_caller]
+        fn handle(&self) -> &'static Location<'static> {
+            std::panic::Location::caller()
+        }
+    }
+
+    impl Tracked for () {}
+    impl Tracked for u8 {}
+
+    // Test that we get the correct location
+    // even with a call through a trait object
+
+    let tracked: &dyn Tracked = &5u8;
+    let location = tracked.handle();
+    let expected_line = line!() - 1;
+    assert_eq!(location.file(), file!());
+    assert_eq!(location.line(), expected_line);
+    assert_eq!(location.column(), 28);
+
+    const TRACKED: &dyn Tracked = &();
+    let location = TRACKED.handle();
+    let expected_line = line!() - 1;
+    assert_eq!(location.file(), file!());
+    assert_eq!(location.line(), expected_line);
+    assert_eq!(location.column(), 28);
+}
+
+fn test_trait_obj2() {
+    // track_caller on the impl but not the trait.
+    pub trait Foo {
+        fn foo(&self) -> &'static Location<'static>;
+    }
+
+    struct Bar;
+    impl Foo for Bar {
+        #[track_caller]
+        fn foo(&self) -> &'static Location<'static> {
+            std::panic::Location::caller()
+        }
+    }
+    let expected_line = line!() - 4; // the `fn` signature above
+
+    let f = &Bar as &dyn Foo;
+    let loc = f.foo(); // trait doesn't track, so we don't point at this call site
+    assert_eq!(loc.file(), file!());
+    assert_eq!(loc.line(), expected_line);
+}
+
+fn main() {
+    let location = Location::caller();
+    let expected_line = line!() - 1;
+    assert_eq!(location.file(), file!());
+    assert_eq!(location.line(), expected_line);
+    assert_eq!(location.column(), 20);
+
+    let tracked = tracked();
+    let expected_line = line!() - 1;
+    assert_eq!(tracked.file(), file!());
+    assert_eq!(tracked.line(), expected_line);
+    assert_eq!(tracked.column(), 19);
+
+    let nested = nested_intrinsic();
+    assert_eq!(nested.file(), file!());
+    assert_eq!(nested.line(), 11);
+    assert_eq!(nested.column(), 5);
+
+    let contained = nested_tracked();
+    assert_eq!(contained.file(), file!());
+    assert_eq!(contained.line(), 15);
+    assert_eq!(contained.column(), 5);
+
+    // `Location::caller()` in a macro should behave similarly to `file!` and `line!`,
+    // i.e. point to where the macro was invoked, instead of the macro itself.
+    let inmacro = caller_location_from_macro!();
+    let expected_line = line!() - 1;
+    assert_eq!(inmacro.file(), file!());
+    assert_eq!(inmacro.line(), expected_line);
+    assert_eq!(inmacro.column(), 19);
+
+    let intrinsic = core::intrinsics::caller_location();
+    let expected_line = line!() - 1;
+    assert_eq!(intrinsic.file(), file!());
+    assert_eq!(intrinsic.line(), expected_line);
+    assert_eq!(intrinsic.column(), 21);
+
+    test_fn_ptr();
+    test_trait_obj();
+    test_trait_obj2();
+}
diff --git a/src/tools/miri/tests/pass/transmute_ptr.rs b/src/tools/miri/tests/pass/transmute_ptr.rs
new file mode 100644
index 000000000000..fd9d457e440e
--- /dev/null
+++ b/src/tools/miri/tests/pass/transmute_ptr.rs
@@ -0,0 +1,52 @@
+#![feature(strict_provenance)]
+use std::{mem, ptr};
+
+fn t1() {
+    // If we are careful, we can exploit data layout...
+    // This is a tricky case since we are transmuting a ScalarPair type to a non-ScalarPair type.
+    let raw = unsafe { mem::transmute::<&[u8], [*const u8; 2]>(&[42]) };
+    let ptr: *const u8 = unsafe { mem::transmute_copy(&raw) };
+    assert_eq!(unsafe { *ptr }, 42);
+}
+
+#[cfg(target_pointer_width = "64")]
+const PTR_SIZE: usize = 8;
+#[cfg(target_pointer_width = "32")]
+const PTR_SIZE: usize = 4;
+
+fn t2() {
+    let bad = unsafe { mem::transmute::<&[u8], [u8; 2 * PTR_SIZE]>(&[1u8]) };
+    let _val = bad[0] + bad[bad.len() - 1];
+}
+
+fn ptr_integer_array() {
+    let r = &mut 42;
+    let _i: [usize; 1] = unsafe { mem::transmute(r) };
+
+    let _x: [u8; PTR_SIZE] = unsafe { mem::transmute(&0) };
+}
+
+fn ptr_in_two_halves() {
+    unsafe {
+        let ptr = &0 as *const i32;
+        let arr = [ptr; 2];
+        // We want to do a scalar read of a pointer at offset PTR_SIZE/2 into this array. But we
+        // cannot use a packed struct or `read_unaligned`, as those use the memcpy code path in
+        // Miri. So instead we shift the entire array by a bit and then the actual read we want to
+        // do is perfectly aligned.
+        let mut target_arr = [ptr::null::<i32>(); 3];
+        let target = target_arr.as_mut_ptr().cast::<u8>();
+        target.add(PTR_SIZE / 2).cast::<[*const i32; 2]>().write_unaligned(arr);
+        // Now target_arr[1] is a mix of the two `ptr` we had stored in `arr`.
+        let strange_ptr = target_arr[1];
+        // Check that the provenance works out.
+        assert_eq!(*strange_ptr.with_addr(ptr.addr()), 0);
+    }
+}
+
+fn main() {
+    t1();
+    t2();
+    ptr_integer_array();
+    ptr_in_two_halves();
+}
diff --git a/src/tools/miri/tests/pass/trivial.rs b/src/tools/miri/tests/pass/trivial.rs
new file mode 100644
index 000000000000..891d11520656
--- /dev/null
+++ b/src/tools/miri/tests/pass/trivial.rs
@@ -0,0 +1,11 @@
+fn empty() {}
+
+fn unit_var() {
+    let x = ();
+    x
+}
+
+fn main() {
+    empty();
+    unit_var();
+}
diff --git a/src/tools/miri/tests/pass/try-operator-custom.rs b/src/tools/miri/tests/pass/try-operator-custom.rs
new file mode 100644
index 000000000000..ccbf63796af5
--- /dev/null
+++ b/src/tools/miri/tests/pass/try-operator-custom.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert!(Ok::<i32, String>(42) == Ok(42));
+}
diff --git a/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor.rs b/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor.rs
new file mode 100644
index 000000000000..5cf91b3f4d19
--- /dev/null
+++ b/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert_eq!(Some(42).map(Some), Some(Some(42)));
+}
diff --git a/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor_pointer_opt.rs b/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor_pointer_opt.rs
new file mode 100644
index 000000000000..fb57d4f4c165
--- /dev/null
+++ b/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor_pointer_opt.rs
@@ -0,0 +1,4 @@
+fn main() {
+    let x = 5;
+    assert_eq!(Some(&x).map(Some), Some(Some(&x)));
+}
diff --git a/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor_struct_pointer_opt.rs b/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor_struct_pointer_opt.rs
new file mode 100644
index 000000000000..44441ed1d36c
--- /dev/null
+++ b/src/tools/miri/tests/pass/tuple_like_enum_variant_constructor_struct_pointer_opt.rs
@@ -0,0 +1,33 @@
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct A<'a> {
+    x: i32,
+    y: &'a i32,
+}
+
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct B<'a>(i32, &'a i32);
+
+#[derive(Copy, Clone, PartialEq, Debug)]
+enum C<'a> {
+    Value(i32, &'a i32),
+    #[allow(dead_code)]
+    NoValue,
+}
+
+fn main() {
+    let x = 5;
+    let a = A { x: 99, y: &x };
+    assert_eq!(Some(a).map(Some), Some(Some(a)));
+    let f = B;
+    assert_eq!(Some(B(42, &x)), Some(f(42, &x)));
+    // the following doesn't compile :(
+    //let f: for<'a> fn(i32, &'a i32) -> B<'a> = B;
+    //assert_eq!(Some(B(42, &x)), Some(f(42, &x)));
+    assert_eq!(B(42, &x), foo(&x, B));
+    let f = C::Value;
+    assert_eq!(C::Value(42, &x), f(42, &x));
+}
+
+fn foo<'a, F: Fn(i32, &'a i32) -> B<'a>>(i: &'a i32, f: F) -> B<'a> {
+    f(42, i)
+}
diff --git a/src/tools/miri/tests/pass/tuple_like_struct_constructor.rs b/src/tools/miri/tests/pass/tuple_like_struct_constructor.rs
new file mode 100644
index 000000000000..05e8893de178
--- /dev/null
+++ b/src/tools/miri/tests/pass/tuple_like_struct_constructor.rs
@@ -0,0 +1,5 @@
+fn main() {
+    #[derive(PartialEq, Eq, Debug)]
+    struct A(i32);
+    assert_eq!(Some(42).map(A), Some(A(42)));
+}
diff --git a/src/tools/miri/tests/pass/u128.rs b/src/tools/miri/tests/pass/u128.rs
new file mode 100644
index 000000000000..0ef7a514cb65
--- /dev/null
+++ b/src/tools/miri/tests/pass/u128.rs
@@ -0,0 +1,70 @@
+#![feature(bench_black_box)]
+use std::hint::black_box as b;
+
+fn main() {
+    let x: u128 = 0xFFFF_FFFF_FFFF_FFFF__FFFF_FFFF_FFFF_FFFF;
+    assert_eq!(0, !x);
+    assert_eq!(0, !x);
+    let y: u128 = 0xFFFF_FFFF_FFFF_FFFF__FFFF_FFFF_FFFF_FFFE;
+    assert_eq!(!1, y);
+    assert_eq!(x, y | 1);
+    assert_eq!(
+        0xFAFF_0000_FF8F_0000__FFFF_0000_FFFF_FFFE,
+        y & 0xFAFF_0000_FF8F_0000__FFFF_0000_FFFF_FFFF,
+    );
+    let z: u128 = 0xABCD_EF;
+    assert_eq!(z * z, 0x734C_C2F2_A521);
+    assert_eq!(z * z * z * z, 0x33EE_0E2A_54E2_59DA_A0E7_8E41);
+    assert_eq!(z + z + z + z, 0x2AF3_7BC);
+    let k: u128 = 0x1234_5678_9ABC_DEFF_EDCB_A987_6543_210;
+    assert_eq!(k + k, 0x2468_ACF1_3579_BDFF_DB97_530E_CA86_420);
+    assert_eq!(0, k - k);
+    assert_eq!(0x1234_5678_9ABC_DEFF_EDCB_A987_5A86_421, k - z);
+    assert_eq!(
+        0x1000_0000_0000_0000_0000_0000_0000_000,
+        k - 0x234_5678_9ABC_DEFF_EDCB_A987_6543_210,
+    );
+    assert_eq!(0x6EF5_DE4C_D3BC_2AAA_3BB4_CC5D_D6EE_8, k / 42);
+    assert_eq!(0, k % 42);
+    assert_eq!(15, z % 42);
+    assert_eq!(0x169D_A8020_CEC18, k % 0x3ACB_FE49_FF24_AC);
+    assert_eq!(0x91A2_B3C4_D5E6_F7, k >> 65);
+    assert_eq!(0xFDB9_7530_ECA8_6420_0000_0000_0000_0000, k << 65);
+    assert!(k > z);
+    assert!(y > k);
+    assert!(y < x);
+    assert_eq!(x as u64, !0);
+    assert_eq!(z as u64, 0xABCD_EF);
+    assert_eq!(k as u64, 0xFEDC_BA98_7654_3210);
+    assert_eq!(k as i128, 0x1234_5678_9ABC_DEFF_EDCB_A987_6543_210);
+    assert_eq!((z as f64) as u128, z);
+    assert_eq!((z as f32) as u128, z);
+    assert_eq!((z as f64 * 16.0) as u128, z * 16);
+    assert_eq!((z as f32 * 16.0) as u128, z * 16);
+    let l: u128 = 432 << 100;
+    assert_eq!((l as f32) as u128, l);
+    assert_eq!((l as f64) as u128, l);
+    // formatting
+    let j: u128 = 1 << 67;
+    assert_eq!("147573952589676412928", format!("{}", j));
+    assert_eq!("80000000000000000", format!("{:x}", j));
+    assert_eq!("20000000000000000000000", format!("{:o}", j));
+    assert_eq!(
+        "10000000000000000000000000000000000000000000000000000000000000000000",
+        format!("{:b}", j),
+    );
+    assert_eq!("340282366920938463463374607431768211455", format!("{}", u128::MAX));
+    assert_eq!("147573952589676412928", format!("{:?}", j));
+    // common traits
+    assert_eq!(x, b(x.clone()));
+    // overflow checks
+    assert_eq!((z).checked_mul(z), Some(0x734C_C2F2_A521));
+    assert_eq!((k).checked_mul(k), None);
+    let l: u128 = b(u128::MAX - 10);
+    let o: u128 = b(17);
+    assert_eq!(l.checked_add(b(11)), None);
+    assert_eq!(l.checked_sub(l), Some(0));
+    assert_eq!(o.checked_sub(b(18)), None);
+    assert_eq!(b(1u128).checked_shl(b(127)), Some(1 << 127));
+    assert_eq!(o.checked_shl(b(128)), None);
+}
diff --git a/src/tools/miri/tests/pass/union-overwrite.rs b/src/tools/miri/tests/pass/union-overwrite.rs
new file mode 100644
index 000000000000..f1d3d9d48101
--- /dev/null
+++ b/src/tools/miri/tests/pass/union-overwrite.rs
@@ -0,0 +1,70 @@
+#[repr(C)]
+#[derive(Clone, Copy)]
+struct Pair<T, U>(T, U);
+#[repr(C)]
+#[derive(Clone, Copy)]
+struct Triple<T>(T, T, T);
+
+#[repr(C)]
+union U<A: Copy, B: Copy> {
+    a: Pair<A, A>,
+    b: B,
+}
+
+#[repr(C)]
+union W<A: Copy, B: Copy> {
+    a: A,
+    b: B,
+}
+
+#[cfg(target_endian = "little")]
+unsafe fn check() {
+    let mut u = U::<u8, u16> { b: 0xDE_DE };
+    u.a.0 = 0xBE;
+    assert_eq!(u.b, 0xDE_BE);
+
+    let mut u = U::<u16, u32> { b: 0xDEAD_DEAD };
+    u.a.0 = 0xBEEF;
+    assert_eq!(u.b, 0xDEAD_BEEF);
+
+    let mut u = U::<u32, u64> { b: 0xDEADBEEF_DEADBEEF };
+    u.a.0 = 0xBAADF00D;
+    assert_eq!(u.b, 0xDEADBEEF_BAADF00D);
+
+    let mut w = W::<Pair<Triple<u8>, u8>, u32> { b: 0xDEAD_DEAD };
+    w.a.0 = Triple(0, 0, 0);
+    assert_eq!(w.b, 0xDE00_0000);
+
+    let mut w = W::<Pair<u8, Triple<u8>>, u32> { b: 0xDEAD_DEAD };
+    w.a.1 = Triple(0, 0, 0);
+    assert_eq!(w.b, 0x0000_00AD);
+}
+
+#[cfg(target_endian = "big")]
+unsafe fn check() {
+    let mut u = U::<u8, u16> { b: 0xDE_DE };
+    u.a.0 = 0xBE;
+    assert_eq!(u.b, 0xBE_DE);
+
+    let mut u = U::<u16, u32> { b: 0xDEAD_DEAD };
+    u.a.0 = 0xBEEF;
+    assert_eq!(u.b, 0xBEEF_DEAD);
+
+    let mut u = U::<u32, u64> { b: 0xDEADBEEF_DEADBEEF };
+    u.a.0 = 0xBAADF00D;
+    assert_eq!(u.b, 0xBAADF00D_DEADBEEF);
+
+    let mut w = W::<Pair<Triple<u8>, u8>, u32> { b: 0xDEAD_DEAD };
+    w.a.0 = Triple(0, 0, 0);
+    assert_eq!(w.b, 0x0000_00AD);
+
+    let mut w = W::<Pair<u8, Triple<u8>>, u32> { b: 0xDEAD_DEAD };
+    w.a.1 = Triple(0, 0, 0);
+    assert_eq!(w.b, 0xDE00_0000);
+}
+
+fn main() {
+    unsafe {
+        check();
+    }
+}
diff --git a/src/tools/miri/tests/pass/union.rs b/src/tools/miri/tests/pass/union.rs
new file mode 100644
index 000000000000..8a6dd49f4503
--- /dev/null
+++ b/src/tools/miri/tests/pass/union.rs
@@ -0,0 +1,91 @@
+fn main() {
+    a();
+    b();
+    c();
+    d();
+}
+
+fn a() {
+    #[allow(dead_code)]
+    union U {
+        f1: u32,
+        f2: f32,
+    }
+    let mut u = U { f1: 1 };
+    unsafe {
+        let b1 = &mut u.f1;
+        *b1 = 5;
+    }
+    assert_eq!(unsafe { u.f1 }, 5);
+}
+
+fn b() {
+    #[derive(Copy, Clone)]
+    struct S {
+        x: u32,
+        y: u32,
+    }
+
+    #[allow(dead_code)]
+    union U {
+        s: S,
+        both: u64,
+    }
+    let mut u = U { s: S { x: 1, y: 2 } };
+    unsafe {
+        let bx = &mut u.s.x;
+        let by = &mut u.s.y;
+        *bx = 5;
+        *by = 10;
+    }
+    assert_eq!(unsafe { u.s.x }, 5);
+    assert_eq!(unsafe { u.s.y }, 10);
+}
+
+fn c() {
+    #[repr(u32)]
+    enum Tag {
+        I,
+        F,
+    }
+
+    #[repr(C)]
+    union U {
+        i: i32,
+        f: f32,
+    }
+
+    #[repr(C)]
+    struct Value {
+        tag: Tag,
+        u: U,
+    }
+
+    fn is_zero(v: Value) -> bool {
+        unsafe {
+            match v {
+                Value { tag: Tag::I, u: U { i: 0 } } => true,
+                Value { tag: Tag::F, u: U { f } } => f == 0.0,
+                _ => false,
+            }
+        }
+    }
+    assert!(is_zero(Value { tag: Tag::I, u: U { i: 0 } }));
+    assert!(is_zero(Value { tag: Tag::F, u: U { f: 0.0 } }));
+    assert!(!is_zero(Value { tag: Tag::I, u: U { i: 1 } }));
+    assert!(!is_zero(Value { tag: Tag::F, u: U { f: 42.0 } }));
+}
+
+fn d() {
+    union MyUnion {
+        f1: u32,
+        f2: f32,
+    }
+    let u = MyUnion { f1: 10 };
+    unsafe {
+        match u {
+            MyUnion { f1: 10 } => {}
+            MyUnion { f2: _f2 } => panic!("foo"),
+        }
+    }
+}
diff --git a/src/tools/miri/tests/pass/unops.rs b/src/tools/miri/tests/pass/unops.rs
new file mode 100644
index 000000000000..f23f68ccbad0
--- /dev/null
+++ b/src/tools/miri/tests/pass/unops.rs
@@ -0,0 +1,5 @@
+fn main() {
+    assert_eq!(!true, false);
+    assert_eq!(!0xFFu16, 0xFF00);
+    assert_eq!(-{ 1i16 }, -1i16);
+}
diff --git a/src/tools/miri/tests/pass/unsized.rs b/src/tools/miri/tests/pass/unsized.rs
new file mode 100644
index 000000000000..d9beac4327d7
--- /dev/null
+++ b/src/tools/miri/tests/pass/unsized.rs
@@ -0,0 +1,36 @@
+#![feature(unsized_tuple_coercion)]
+#![feature(unsized_fn_params)]
+
+use std::mem;
+
+fn unsized_tuple() {
+    let x: &(i32, i32, [i32]) = &(0, 1, [2, 3]);
+    let y: &(i32, i32, [i32]) = &(0, 1, [2, 3, 4]);
+    let mut a = [y, x];
+    a.sort();
+    assert_eq!(a, [x, y]);
+
+    assert_eq!(&format!("{:?}", a), "[(0, 1, [2, 3]), (0, 1, [2, 3, 4])]");
+    assert_eq!(mem::size_of_val(x), 16);
+}
+
+fn unsized_params() {
+    pub fn f0(_f: dyn FnOnce()) {}
+    pub fn f1(_s: str) {}
+    pub fn f2(_x: i32, _y: [i32]) {}
+    pub fn f3(_p: dyn Send) {}
+
+    let c: Box<dyn FnOnce()> = Box::new(|| {});
+    f0(*c);
+    let foo = "foo".to_string().into_boxed_str();
+    f1(*foo);
+    let sl: Box<[i32]> = [0, 1, 2].to_vec().into_boxed_slice();
+    f2(5, *sl);
+    let p: Box<dyn Send> = Box::new((1, 2));
+    f3(*p);
+}
+
+fn main() {
+    unsized_tuple();
+    unsized_params();
+}
diff --git a/src/tools/miri/tests/pass/validation_lifetime_resolution.rs b/src/tools/miri/tests/pass/validation_lifetime_resolution.rs
new file mode 100644
index 000000000000..f5eef2ad6e75
--- /dev/null
+++ b/src/tools/miri/tests/pass/validation_lifetime_resolution.rs
@@ -0,0 +1,36 @@
+trait Id {
+    type Out;
+
+    fn id(self) -> Self::Out;
+}
+
+impl<'a> Id for &'a mut i32 {
+    type Out = &'a mut i32;
+
+    fn id(self) -> Self {
+        self
+    }
+}
+
+impl<'a> Id for &'a mut u32 {
+    type Out = &'a mut u32;
+
+    fn id(self) -> Self {
+        self
+    }
+}
+
+fn foo<T>(mut x: T)
+where
+    for<'a> &'a mut T: Id,
+{
+    let x = &mut x;
+    let _y = x.id();
+    // Inspecting the trace should show that `_y` has a type involving a local lifetime, when it gets validated.
+    // Unfortunately, there doesn't seem to be a way to actually have a test fail if it does not have the right
+    // type. Currently, this is *not* working correctly; see <https://github.com/rust-lang/miri/issues/298>.
+}
+
+fn main() {
+    foo(3)
+}
diff --git a/src/tools/miri/tests/pass/vec-matching-fold.rs b/src/tools/miri/tests/pass/vec-matching-fold.rs
new file mode 100644
index 000000000000..3a869703bf96
--- /dev/null
+++ b/src/tools/miri/tests/pass/vec-matching-fold.rs
@@ -0,0 +1,40 @@
+use std::fmt::Debug;
+
+fn foldl<T, U, F>(values: &[T], initial: U, mut function: F) -> U
+where
+    U: Clone + Debug,
+    T: Debug,
+    F: FnMut(U, &T) -> U,
+{
+    match values {
+        [head, tail @ ..] => foldl(tail, function(initial, head), function),
+        [] => {
+            let res = initial.clone();
+            res
+        }
+    }
+}
+
+fn foldr<T, U, F>(values: &[T], initial: U, mut function: F) -> U
+where
+    U: Clone,
+    F: FnMut(&T, U) -> U,
+{
+    match values {
+        [head @ .., tail] => foldr(head, function(tail, initial), function),
+        [] => {
+            let res = initial.clone();
+            res
+        }
+    }
+}
+
+pub fn main() {
+    let x = &[1, 2, 3, 4, 5];
+
+    let product = foldl(x, 1, |a, b| a * *b);
+    assert_eq!(product, 120);
+
+    let sum = foldr(x, 0, |a, b| *a + b);
+    assert_eq!(sum, 15);
+}
diff --git a/src/tools/miri/tests/pass/vec.rs b/src/tools/miri/tests/pass/vec.rs
new file mode 100644
index 000000000000..26732cec5eb9
--- /dev/null
+++ b/src/tools/miri/tests/pass/vec.rs
@@ -0,0 +1,176 @@
+//@compile-flags: -Zmiri-strict-provenance
+// Gather all references from a mutable iterator and make sure Miri notices if
+// using them is dangerous.
+fn test_all_refs<'a, T: 'a>(dummy: &mut T, iter: impl Iterator<Item = &'a mut T>) {
+    // Gather all those references.
+    let mut refs: Vec<&mut T> = iter.collect();
+    // Use them all. Twice, to be sure we got all interleavings.
+    for r in refs.iter_mut() {
+        std::mem::swap(dummy, r);
+    }
+    for r in refs {
+        std::mem::swap(dummy, r);
+    }
+}
+
+fn make_vec() -> Vec<u8> {
+    let mut v = Vec::with_capacity(4);
+    v.push(1);
+    v.push(2);
+    v
+}
+
+fn make_vec_macro() -> Vec<u8> {
+    vec![1, 2]
+}
+
+fn make_vec_macro_repeat() -> Vec<u8> {
+    vec![42; 5]
+}
+
+fn make_vec_macro_repeat_zeroed() -> Vec<u8> {
+    vec![0; 7]
+}
+
+fn vec_into_iter() -> u8 {
+    vec![1, 2, 3, 4].into_iter().map(|x| x * x).fold(0, |x, y| x + y)
+}
+
+fn vec_into_iter_rev() -> u8 {
+    vec![1, 2, 3, 4].into_iter().map(|x| x * x).fold(0, |x, y| x + y)
+}
+
+fn vec_into_iter_zst() -> usize {
+    vec![[0u64; 0], [0u64; 0]].into_iter().rev().map(|x| x.len()).sum()
+}
+
+fn vec_into_iter_rev_zst() -> usize {
+    vec![[0u64; 0], [0u64; 0]].into_iter().rev().map(|x| x.len()).sum()
+}
+
+fn vec_iter_and_mut() {
+    let mut v = vec![1, 2, 3, 4];
+    for i in v.iter_mut() {
+        *i += 1;
+    }
+    assert_eq!(v.iter().sum::<i32>(), 2 + 3 + 4 + 5);
+
+    test_all_refs(&mut 13, v.iter_mut());
+}
+
+fn vec_iter_and_mut_rev() {
+    let mut v = vec![1, 2, 3, 4];
+    for i in v.iter_mut().rev() {
+        *i += 1;
+    }
+    assert_eq!(v.iter().sum::<i32>(), 2 + 3 + 4 + 5);
+}
+
+fn vec_reallocate() -> Vec<u8> {
+    let mut v = vec![1, 2];
+    v.push(3);
+    v.push(4);
+    v.push(5);
+    v
+}
+
+fn vec_push_ptr_stable() {
+    let mut v = Vec::with_capacity(10);
+    v.push(0);
+    let v0 = unsafe { &mut *(&mut v[0] as *mut _) }; // laundering the lifetime -- we take care that `v` does not reallocate, so that's okay.
+    v.push(1);
+    let _val = *v0;
+}
+
+fn vec_extend_ptr_stable() {
+    let mut v = Vec::with_capacity(10);
+    v.push(0);
+    let v0 = unsafe { &mut *(&mut v[0] as *mut _) }; // laundering the lifetime -- we take care that `v` does not reallocate, so that's okay.
+    // `slice::Iter` (with `T: Copy`) specialization
+    v.extend(&[1]);
+    let _val = *v0;
+    // `vec::IntoIter` specialization
+    v.extend(vec![2]);
+    let _val = *v0;
+    // `TrustedLen` specialization
+    v.extend(std::iter::once(3));
+    let _val = *v0;
+    // base case
+    v.extend(std::iter::once(3).filter(|_| true));
+    let _val = *v0;
+}
+
+fn vec_truncate_ptr_stable() {
+    let mut v = vec![0; 10];
+    let v0 = unsafe { &mut *(&mut v[0] as *mut _) }; // laundering the lifetime -- we take care that `v` does not reallocate, so that's okay.
+    v.truncate(5);
+    let _val = *v0;
+}
+
+fn push_str_ptr_stable() {
+    let mut buf = String::with_capacity(11);
+    buf.push_str("hello");
+    let hello: &str = unsafe { &*(buf.as_str() as *const _) }; // laundering the lifetime -- we take care that `buf` does not reallocate, so that's okay.
+    buf.push_str(" world");
+    assert_eq!(format!("{}", hello), "hello");
+}
+
+fn sort() {
+    let mut v = vec![1; 20];
+    v.push(0);
+    v.sort();
+}
+
+fn swap() {
+    let mut v = vec![1, 2, 3, 4];
+    v.swap(2, 2);
+}
+
+fn swap_remove() {
+    let mut a = 0;
+    let mut b = 1;
+    let mut vec = vec![&mut a, &mut b];
+
+    vec.swap_remove(1);
+}
+
+fn reverse() {
+    #[repr(align(2))]
+    #[derive(Debug)]
+    struct Foo(u8);
+
+    let mut v: Vec<_> = (0..50).map(Foo).collect();
+    v.reverse();
+    assert!(v[0].0 == 49);
+}
+
+fn main() {
+    assert_eq!(vec_reallocate().len(), 5);
+
+    assert_eq!(vec_into_iter(), 30);
+    assert_eq!(vec_into_iter_rev(), 30);
+    vec_iter_and_mut();
+    assert_eq!(vec_into_iter_zst(), 0);
+    assert_eq!(vec_into_iter_rev_zst(), 0);
+    vec_iter_and_mut_rev();
+
+    assert_eq!(make_vec().capacity(), 4);
+    assert_eq!(make_vec_macro(), [1, 2]);
+    assert_eq!(make_vec_macro_repeat(), [42; 5]);
+    assert_eq!(make_vec_macro_repeat_zeroed(), [0; 7]);
+
+    // Test interesting empty slice comparison
+    // (one is a real pointer, one an integer pointer).
+    assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
+
+    // liballoc has a more extensive test of this, but let's at least do a smoke test here.
+    vec_push_ptr_stable();
+    vec_extend_ptr_stable();
+    vec_truncate_ptr_stable();
+    push_str_ptr_stable();
+
+    sort();
+    swap();
+    swap_remove();
+    reverse();
+}
diff --git a/src/tools/miri/tests/pass/vecdeque.rs b/src/tools/miri/tests/pass/vecdeque.rs
new file mode 100644
index 000000000000..6f56f9d103e9
--- /dev/null
+++ b/src/tools/miri/tests/pass/vecdeque.rs
@@ -0,0 +1,51 @@
+//@compile-flags: -Zmiri-strict-provenance
+use std::collections::VecDeque;
+
+fn test_all_refs<'a, T: 'a>(dummy: &mut T, iter: impl Iterator<Item = &'a mut T>) {
+    // Gather all those references.
+    let mut refs: Vec<&mut T> = iter.collect();
+    // Use them all. Twice, to be sure we got all interleavings.
+    for r in refs.iter_mut() {
+        std::mem::swap(dummy, r);
+    }
+    for r in refs {
+        std::mem::swap(dummy, r);
+    }
+}
+
+fn main() {
+    let mut dst = VecDeque::new();
+    dst.push_front(Box::new(1));
+    dst.push_front(Box::new(2));
+    dst.pop_back();
+
+    let mut src = VecDeque::new();
+    src.push_front(Box::new(2));
+    dst.append(&mut src);
+    for a in dst.iter() {
+        assert_eq!(**a, 2);
+    }
+
+    // Regression test for Debug impl's
+    println!("{:?} {:?}", dst, dst.iter());
+    println!("{:?}", VecDeque::<u32>::new().iter());
+
+    for a in dst {
+        assert_eq!(*a, 2);
+    }
+
+    // # Aliasing tests.
+    let mut v = std::collections::VecDeque::new();
+    v.push_back(1);
+    v.push_back(2);
+
+    // Test `fold` bad aliasing.
+    let mut it = v.iter_mut();
+    let ref0 = it.next().unwrap();
+    let sum = it.fold(0, |x, y| x + *y);
+    assert_eq!(*ref0 + sum, 3);
+
+    // Test general iterator aliasing.
+    v.push_front(0);
+    test_all_refs(&mut 0, v.iter_mut());
+}
diff --git a/src/tools/miri/tests/pass/vecdeque.stdout b/src/tools/miri/tests/pass/vecdeque.stdout
new file mode 100644
index 000000000000..63de960ee2bd
--- /dev/null
+++ b/src/tools/miri/tests/pass/vecdeque.stdout
@@ -0,0 +1,2 @@
+[2, 2] Iter([2, 2], [])
+Iter([], [])
diff --git a/src/tools/miri/tests/pass/volatile.rs b/src/tools/miri/tests/pass/volatile.rs
new file mode 100644
index 000000000000..c9799801455c
--- /dev/null
+++ b/src/tools/miri/tests/pass/volatile.rs
@@ -0,0 +1,12 @@
+// related: #58645
+#![feature(core_intrinsics)]
+use std::intrinsics::{volatile_load, volatile_store};
+
+pub fn main() {
+    unsafe {
+        let i: &mut (isize, isize) = &mut (0, 0);
+        volatile_store(i, (1, 2));
+        assert_eq!(volatile_load(i), (1, 2));
+        assert_eq!(i, &mut (1, 2));
+    }
+}
diff --git a/src/tools/miri/tests/pass/weak_memory/extra_cpp.rs b/src/tools/miri/tests/pass/weak_memory/extra_cpp.rs
new file mode 100644
index 000000000000..07cbb4a803f1
--- /dev/null
+++ b/src/tools/miri/tests/pass/weak_memory/extra_cpp.rs
@@ -0,0 +1,80 @@
+//@compile-flags: -Zmiri-ignore-leaks
+
+// Tests operations not perfomable through C++'s atomic API
+// but doable in safe (at least sound) Rust.
+
+#![feature(atomic_from_mut)]
+
+use std::sync::atomic::Ordering::*;
+use std::sync::atomic::{AtomicU16, AtomicU32};
+use std::thread::spawn;
+
+fn static_atomic_mut(val: u32) -> &'static mut AtomicU32 {
+    let ret = Box::leak(Box::new(AtomicU32::new(val)));
+    ret
+}
+
+fn split_u32(dword: &mut u32) -> &mut [u16; 2] {
+    unsafe { std::mem::transmute::<&mut u32, &mut [u16; 2]>(dword) }
+}
+
+fn mem_replace() {
+    let mut x = AtomicU32::new(0);
+
+    let old_x = std::mem::replace(&mut x, AtomicU32::new(42));
+
+    assert_eq!(x.load(Relaxed), 42);
+    assert_eq!(old_x.load(Relaxed), 0);
+}
+
+fn assign_to_mut() {
+    let x = static_atomic_mut(0);
+    x.store(1, Relaxed);
+
+    *x = AtomicU32::new(2);
+
+    assert_eq!(x.load(Relaxed), 2);
+}
+
+fn get_mut_write() {
+    let x = static_atomic_mut(0);
+    x.store(1, Relaxed);
+    {
+        let x_mut = x.get_mut();
+        *x_mut = 2;
+    }
+
+    let j1 = spawn(move || x.load(Relaxed));
+
+    let r1 = j1.join().unwrap();
+    assert_eq!(r1, 2);
+}
+
+// This is technically doable in C++ with atomic_ref
+// but little literature exists atm on its involvement
+// in mixed size/atomicity accesses
+fn from_mut_split() {
+    let mut x: u32 = 0;
+
+    {
+        let x_atomic = AtomicU32::from_mut(&mut x);
+        x_atomic.store(u32::from_be(0xabbafafa), Relaxed);
+    }
+
+    // Split the `AtomicU32` into two `AtomicU16`.
+    // Crucially, there is no non-atomic access to `x`! All accesses are atomic, but of different size.
+    let (x_hi, x_lo) = split_u32(&mut x).split_at_mut(1);
+
+    let x_hi_atomic = AtomicU16::from_mut(&mut x_hi[0]);
+    let x_lo_atomic = AtomicU16::from_mut(&mut x_lo[0]);
+
+    assert_eq!(x_hi_atomic.load(Relaxed), u16::from_be(0xabba));
+    assert_eq!(x_lo_atomic.load(Relaxed), u16::from_be(0xfafa));
+}
+
+pub fn main() {
+    get_mut_write();
+    from_mut_split();
+    assign_to_mut();
+    mem_replace();
+}
diff --git a/src/tools/miri/tests/pass/weak_memory/extra_cpp_unsafe.rs b/src/tools/miri/tests/pass/weak_memory/extra_cpp_unsafe.rs
new file mode 100644
index 000000000000..f7e2748408ff
--- /dev/null
+++ b/src/tools/miri/tests/pass/weak_memory/extra_cpp_unsafe.rs
@@ -0,0 +1,40 @@
+//@compile-flags: -Zmiri-ignore-leaks
+
+// Tests operations not perfomable through C++'s atomic API
+// but doable in unsafe Rust which we think *should* be fine.
+// Nonetheless they may be determined as inconsistent with the
+// memory model in the future.
+
+#![feature(atomic_from_mut)]
+
+use std::sync::atomic::AtomicU32;
+use std::sync::atomic::Ordering::*;
+use std::thread::spawn;
+
+fn static_atomic(val: u32) -> &'static AtomicU32 {
+    let ret = Box::leak(Box::new(AtomicU32::new(val)));
+    ret
+}
+
+// We allow perfectly overlapping non-atomic and atomic reads to race
+fn racing_mixed_atomicity_read() {
+    let x = static_atomic(0);
+    x.store(42, Relaxed);
+
+    let j1 = spawn(move || x.load(Relaxed));
+
+    let j2 = spawn(move || {
+        let x_ptr = x as *const AtomicU32 as *const u32;
+        unsafe { x_ptr.read() }
+    });
+
+    let r1 = j1.join().unwrap();
+    let r2 = j2.join().unwrap();
+
+    assert_eq!(r1, 42);
+    assert_eq!(r2, 42);
+}
+
+pub fn main() {
+    racing_mixed_atomicity_read();
+}
diff --git a/src/tools/miri/tests/pass/weak_memory/weak.rs b/src/tools/miri/tests/pass/weak_memory/weak.rs
new file mode 100644
index 000000000000..4c3be6b3559a
--- /dev/null
+++ b/src/tools/miri/tests/pass/weak_memory/weak.rs
@@ -0,0 +1,150 @@
+//@compile-flags: -Zmiri-ignore-leaks -Zmiri-preemption-rate=0
+
+// Tests showing weak memory behaviours are exhibited. All tests
+// return true when the desired behaviour is seen.
+// This is scheduler and pseudo-RNG dependent, so each test is
+// run multiple times until one try returns true.
+// Spurious failure is possible, if you are really unlucky with
+// the RNG and always read the latest value from the store buffer.
+
+use std::sync::atomic::Ordering::*;
+use std::sync::atomic::{fence, AtomicUsize};
+use std::thread::spawn;
+
+#[derive(Copy, Clone)]
+struct EvilSend<T>(pub T);
+
+unsafe impl<T> Send for EvilSend<T> {}
+unsafe impl<T> Sync for EvilSend<T> {}
+
+// We can't create static items because we need to run each test
+// multiple times
+fn static_atomic(val: usize) -> &'static AtomicUsize {
+    let ret = Box::leak(Box::new(AtomicUsize::new(val)));
+    ret
+}
+
+// Spins until it reads the given value
+fn reads_value(loc: &AtomicUsize, val: usize) -> usize {
+    while loc.load(Relaxed) != val {
+        std::hint::spin_loop();
+    }
+    val
+}
+
+fn relaxed() -> bool {
+    let x = static_atomic(0);
+    let j1 = spawn(move || {
+        x.store(1, Relaxed);
+        x.store(2, Relaxed);
+    });
+
+    let j2 = spawn(move || x.load(Relaxed));
+
+    j1.join().unwrap();
+    let r2 = j2.join().unwrap();
+
+    r2 == 1
+}
+
+// https://www.doc.ic.ac.uk/~afd/homepages/papers/pdfs/2017/POPL.pdf Figure 8
+fn seq_cst() -> bool {
+    let x = static_atomic(0);
+
+    let j1 = spawn(move || {
+        x.store(1, Relaxed);
+    });
+
+    let j2 = spawn(move || {
+        x.store(2, SeqCst);
+        x.store(3, SeqCst);
+    });
+
+    let j3 = spawn(move || x.load(SeqCst));
+
+    j1.join().unwrap();
+    j2.join().unwrap();
+    let r3 = j3.join().unwrap();
+
+    r3 == 1
+}
+
+fn initialization_write(add_fence: bool) -> bool {
+    let x = static_atomic(11);
+    assert_eq!(x.load(Relaxed), 11); // work around https://github.com/rust-lang/miri/issues/2164
+
+    let wait = static_atomic(0);
+
+    let j1 = spawn(move || {
+        x.store(22, Relaxed);
+        // Relaxed is intentional. We want to test if the thread 2 reads the initialisation write
+        // after a relaxed write
+        wait.store(1, Relaxed);
+    });
+
+    let j2 = spawn(move || {
+        reads_value(wait, 1);
+        if add_fence {
+            fence(AcqRel);
+        }
+        x.load(Relaxed)
+    });
+
+    j1.join().unwrap();
+    let r2 = j2.join().unwrap();
+
+    r2 == 11
+}
+
+fn faa_replaced_by_load() -> bool {
+    // Example from https://github.com/llvm/llvm-project/issues/56450#issuecomment-1183695905
+    #[no_mangle]
+    pub fn rdmw(storing: &AtomicUsize, sync: &AtomicUsize, loading: &AtomicUsize) -> usize {
+        storing.store(1, Relaxed);
+        fence(Release);
+        // sync.fetch_add(0, Relaxed);
+        sync.load(Relaxed);
+        fence(Acquire);
+        loading.load(Relaxed)
+    }
+
+    let x = static_atomic(0);
+    assert_eq!(x.load(Relaxed), 0); // work around https://github.com/rust-lang/miri/issues/2164
+    let y = static_atomic(0);
+    assert_eq!(y.load(Relaxed), 0); // work around https://github.com/rust-lang/miri/issues/2164
+    let z = static_atomic(0);
+    assert_eq!(z.load(Relaxed), 0); // work around https://github.com/rust-lang/miri/issues/2164
+
+    // Since each thread is so short, we need to make sure that they truely run at the same time
+    // Otherwise t1 will finish before t2 even starts
+    let go = static_atomic(0);
+
+    let t1 = spawn(move || {
+        while go.load(Relaxed) == 0 {}
+        rdmw(y, x, z)
+    });
+
+    let t2 = spawn(move || {
+        while go.load(Relaxed) == 0 {}
+        rdmw(z, x, y)
+    });
+
+    go.store(1, Relaxed);
+
+    let a = t1.join().unwrap();
+    let b = t2.join().unwrap();
+    (a, b) == (0, 0)
+}
+
+/// Asserts that the function returns true at least once in 100 runs
+fn assert_once(f: fn() -> bool) {
+    assert!(std::iter::repeat_with(|| f()).take(100).any(|x| x));
+}
+
+pub fn main() {
+    assert_once(relaxed);
+    assert_once(seq_cst);
+    assert_once(|| initialization_write(false));
+    assert_once(|| initialization_write(true));
+    assert_once(faa_replaced_by_load);
+}
diff --git a/src/tools/miri/tests/pass/without-validation.rs b/src/tools/miri/tests/pass/without-validation.rs
new file mode 100644
index 000000000000..934c44a7deb4
--- /dev/null
+++ b/src/tools/miri/tests/pass/without-validation.rs
@@ -0,0 +1,24 @@
+// When we notice something breaks only without validation, we add a test here.
+//@compile-flags: -Zmiri-disable-validation
+use std::cell::*;
+
+fn refcell_unsize() {
+    let cell: RefCell<[i32; 3]> = RefCell::new([1, 2, 3]);
+    {
+        let mut cellref: RefMut<'_, [i32; 3]> = cell.borrow_mut();
+        cellref[0] = 4;
+        let mut coerced: RefMut<'_, [i32]> = cellref;
+        coerced[2] = 5;
+    }
+    {
+        let comp: &mut [i32] = &mut [4, 2, 5];
+        let cellref: Ref<'_, [i32; 3]> = cell.borrow();
+        assert_eq!(&*cellref, comp);
+        let coerced: Ref<'_, [i32]> = cellref;
+        assert_eq!(&*coerced, comp);
+    }
+}
+
+fn main() {
+    refcell_unsize();
+}
diff --git a/src/tools/miri/tests/pass/write-bytes.rs b/src/tools/miri/tests/pass/write-bytes.rs
new file mode 100644
index 000000000000..b2050c5393e2
--- /dev/null
+++ b/src/tools/miri/tests/pass/write-bytes.rs
@@ -0,0 +1,85 @@
+#![feature(core_intrinsics)] // for `volatile_set_memory`
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+struct Foo {
+    a: u64,
+    b: u64,
+    c: u64,
+}
+
+fn main() {
+    const LENGTH: usize = 10;
+    let mut v: [u64; LENGTH] = [0; LENGTH];
+
+    for idx in 0..LENGTH {
+        assert_eq!(v[idx], 0);
+    }
+
+    unsafe {
+        let p = v.as_mut_ptr();
+        ::std::ptr::write_bytes(p, 0xab, LENGTH);
+    }
+
+    for idx in 0..LENGTH {
+        assert_eq!(v[idx], 0xabababababababab);
+    }
+
+    // -----
+
+    let mut w: [Foo; LENGTH] = [Foo { a: 0, b: 0, c: 0 }; LENGTH];
+    for idx in 0..LENGTH {
+        assert_eq!(w[idx].a, 0);
+        assert_eq!(w[idx].b, 0);
+        assert_eq!(w[idx].c, 0);
+    }
+
+    unsafe {
+        let p = w.as_mut_ptr();
+        ::std::ptr::write_bytes(p, 0xcd, LENGTH);
+    }
+
+    for idx in 0..LENGTH {
+        assert_eq!(w[idx].a, 0xcdcdcdcdcdcdcdcd);
+        assert_eq!(w[idx].b, 0xcdcdcdcdcdcdcdcd);
+        assert_eq!(w[idx].c, 0xcdcdcdcdcdcdcdcd);
+    }
+
+    // -----
+    // `std::intrinsics::volatile_set_memory` should behave identically
+
+    let mut v: [u64; LENGTH] = [0; LENGTH];
+
+    for idx in 0..LENGTH {
+        assert_eq!(v[idx], 0);
+    }
+
+    unsafe {
+        let p = v.as_mut_ptr();
+        ::std::intrinsics::volatile_set_memory(p, 0xab, LENGTH);
+    }
+
+    for idx in 0..LENGTH {
+        assert_eq!(v[idx], 0xabababababababab);
+    }
+
+    // -----
+
+    let mut w: [Foo; LENGTH] = [Foo { a: 0, b: 0, c: 0 }; LENGTH];
+    for idx in 0..LENGTH {
+        assert_eq!(w[idx].a, 0);
+        assert_eq!(w[idx].b, 0);
+        assert_eq!(w[idx].c, 0);
+    }
+
+    unsafe {
+        let p = w.as_mut_ptr();
+        ::std::intrinsics::volatile_set_memory(p, 0xcd, LENGTH);
+    }
+
+    for idx in 0..LENGTH {
+        assert_eq!(w[idx].a, 0xcdcdcdcdcdcdcdcd);
+        assert_eq!(w[idx].b, 0xcdcdcdcdcdcdcdcd);
+        assert_eq!(w[idx].c, 0xcdcdcdcdcdcdcdcd);
+    }
+}
diff --git a/src/tools/miri/tests/pass/wtf8.rs b/src/tools/miri/tests/pass/wtf8.rs
new file mode 100644
index 000000000000..be8348654a32
--- /dev/null
+++ b/src/tools/miri/tests/pass/wtf8.rs
@@ -0,0 +1,22 @@
+//@only-target-windows
+
+use std::ffi::{OsStr, OsString};
+use std::os::windows::ffi::{OsStrExt, OsStringExt};
+
+fn test1() {
+    let base = "a\té \u{7f}💩\r";
+    let mut base: Vec<u16> = OsStr::new(base).encode_wide().collect();
+    base.push(0xD800);
+    let _res = OsString::from_wide(&base);
+}
+
+fn test2() {
+    let mut base: Vec<u16> = OsStr::new("aé ").encode_wide().collect();
+    base.push(0xD83D);
+    let mut _res: Vec<u16> = OsString::from_wide(&base).encode_wide().collect();
+}
+
+fn main() {
+    test1();
+    test2();
+}
diff --git a/src/tools/miri/tests/pass/zst.rs b/src/tools/miri/tests/pass/zst.rs
new file mode 100644
index 000000000000..a56386a691f8
--- /dev/null
+++ b/src/tools/miri/tests/pass/zst.rs
@@ -0,0 +1,29 @@
+//@compile-flags: -Zmiri-permissive-provenance
+#[derive(PartialEq, Debug)]
+struct A;
+
+fn zst_ret() -> A {
+    A
+}
+
+fn use_zst() -> A {
+    let a = A;
+    a
+}
+
+fn main() {
+    // Not using the () type here, as writes of that type do not even have MIR generated.
+    // Also not assigning directly as that's array initialization, not assignment.
+    let zst_val = [1u8; 0];
+
+    assert_eq!(zst_ret(), A);
+    assert_eq!(use_zst(), A);
+    let x = 42 as *mut [u8; 0];
+    // Reading and writing is ok.
+    unsafe {
+        *x = zst_val;
+    }
+    unsafe {
+        let _y = *x;
+    }
+}
diff --git a/src/tools/miri/tests/pass/zst_box.rs b/src/tools/miri/tests/pass/zst_box.rs
new file mode 100644
index 000000000000..12138be5af97
--- /dev/null
+++ b/src/tools/miri/tests/pass/zst_box.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let x = Box::new(());
+    let y = Box::new(());
+    drop(y);
+    let z = Box::new(());
+    drop(x);
+    drop(z);
+}
diff --git a/src/tools/miri/tests/pass/zst_variant_drop.rs b/src/tools/miri/tests/pass/zst_variant_drop.rs
new file mode 100644
index 000000000000..a76f64ce29df
--- /dev/null
+++ b/src/tools/miri/tests/pass/zst_variant_drop.rs
@@ -0,0 +1,23 @@
+struct Foo;
+impl Drop for Foo {
+    fn drop(&mut self) {
+        unsafe {
+            FOO = true;
+        }
+    }
+}
+
+static mut FOO: bool = false;
+
+enum Bar {
+    A(Box<i32>),
+    B(Foo),
+}
+
+fn main() {
+    assert!(unsafe { !FOO });
+    drop(Bar::A(Box::new(42)));
+    assert!(unsafe { !FOO });
+    drop(Bar::B(Foo));
+    assert!(unsafe { FOO });
+}
diff --git a/src/tools/miri/triagebot.toml b/src/tools/miri/triagebot.toml
new file mode 100644
index 000000000000..21a154cafd40
--- /dev/null
+++ b/src/tools/miri/triagebot.toml
@@ -0,0 +1,11 @@
+[relabel]
+allow-unauthenticated = [
+    "A-*",
+    "C-*",
+    "E-*",
+    "I-*",
+    "S-*",
+ ]
+
+# Gives us the commands 'ready', 'author', 'blocked'
+[shortcut]
diff --git a/src/tools/publish_toolstate.py b/src/tools/publish_toolstate.py
index c0cef8f7b0a0..9c16ef2cbecc 100755
--- a/src/tools/publish_toolstate.py
+++ b/src/tools/publish_toolstate.py
@@ -30,7 +30,6 @@ except ImportError:
 # These should be collaborators of the rust-lang/rust repository (with at least
 # read privileges on it). CI will fail otherwise.
 MAINTAINERS = {
-    'miri': {'oli-obk', 'RalfJung'},
     'book': {'carols10cents'},
     'nomicon': {'frewsxcv', 'Gankra', 'JohnTitor'},
     'reference': {'Havvy', 'matthewjasper', 'ehuss'},
@@ -41,7 +40,6 @@ MAINTAINERS = {
 }
 
 LABELS = {
-    'miri': ['A-miri', 'C-bug'],
     'book': ['C-bug'],
     'nomicon': ['C-bug'],
     'reference': ['C-bug'],
@@ -52,7 +50,6 @@ LABELS = {
 }
 
 REPOS = {
-    'miri': 'https://github.com/rust-lang/miri',
     'book': 'https://github.com/rust-lang/book',
     'nomicon': 'https://github.com/rust-lang/nomicon',
     'reference': 'https://github.com/rust-lang/reference',
@@ -239,16 +236,10 @@ def update_latest(
                     message += '{} (cc {}).\n' \
                         .format(title, maintainers)
                     # See if we need to create an issue.
-                    if tool == 'miri':
-                        # Create issue if tests used to pass before. Don't open a *second*
-                        # issue when we regress from "test-fail" to "build-fail".
-                        if old == 'test-pass':
-                            create_issue_for_status = new
-                    else:
-                        # Create issue if things no longer build.
-                        # (No issue for mere test failures to avoid spurious issues.)
-                        if new == 'build-fail':
-                            create_issue_for_status = new
+                    # Create issue if things no longer build.
+                    # (No issue for mere test failures to avoid spurious issues.)
+                    if new == 'build-fail':
+                        create_issue_for_status = new
 
             if create_issue_for_status is not None:
                 try:
diff --git a/src/tools/replace-version-placeholder/src/main.rs b/src/tools/replace-version-placeholder/src/main.rs
index 146e53f2e9a0..33b35d054157 100644
--- a/src/tools/replace-version-placeholder/src/main.rs
+++ b/src/tools/replace-version-placeholder/src/main.rs
@@ -14,7 +14,7 @@ fn main() {
             walk::filter_dirs(path)
                 // We exempt these as they require the placeholder
                 // for their operation
-                || path.ends_with("compiler/rustc_passes/src/lib_features.rs")
+                || path.ends_with("compiler/rustc_attr/src/builtin.rs")
                 || path.ends_with("src/tools/tidy/src/features/version.rs")
                 || path.ends_with("src/tools/replace-version-placeholder")
         },
diff --git a/src/tools/rust-analyzer/.github/workflows/ci.yaml b/src/tools/rust-analyzer/.github/workflows/ci.yaml
index a70252fa65a5..1563ee0b1438 100644
--- a/src/tools/rust-analyzer/.github/workflows/ci.yaml
+++ b/src/tools/rust-analyzer/.github/workflows/ci.yaml
@@ -6,15 +6,15 @@ on:
   pull_request:
   push:
     branches:
-    - auto
-    - try
+      - auto
+      - try
 
 env:
   CARGO_INCREMENTAL: 0
   CARGO_NET_RETRY: 10
   CI: 1
   RUST_BACKTRACE: short
-  RUSTFLAGS: "-D warnings -W unreachable-pub -W rust-2021-compatibility"
+  RUSTFLAGS: "-D warnings -W unreachable-pub -W bare-trait-objects"
   RUSTUP_MAX_RETRIES: 10
 
 jobs:
@@ -31,25 +31,25 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
-      with:
-        ref: ${{ github.event.pull_request.head.sha }}
-        fetch-depth: 20
+      - name: Checkout repository
+        uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 20
 
-    - name: Install Rust toolchain
-      run: |
-        rustup update --no-self-update stable
-        rustup component add rustfmt rust-src
+      - name: Install Rust toolchain
+        run: |
+          rustup update --no-self-update stable
+          rustup component add rustfmt rust-src
 
-    - name: Cache Dependencies
-      uses: Swatinem/rust-cache@ce325b60658c1b38465c06cc965b79baf32c1e72
+      - name: Cache Dependencies
+        uses: Swatinem/rust-cache@ce325b60658c1b38465c06cc965b79baf32c1e72
 
-    - name: Compile
-      run: cargo test --no-run --locked
+      - name: Compile
+        run: cargo test --no-run --locked
 
-    - name: Test
-      run: cargo test -- --nocapture --quiet
+      - name: Test
+        run: cargo test -- --nocapture --quiet
 
   # Weird targets to catch non-portable code
   rust-cross:
@@ -64,25 +64,25 @@ jobs:
       targets_ide: "wasm32-unknown-unknown"
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
+      - name: Checkout repository
+        uses: actions/checkout@v3
 
-    - name: Install Rust toolchain
-      run: |
-        rustup update --no-self-update stable
-        rustup target add ${{ env.targets }} ${{ env.targets_ide }}
+      - name: Install Rust toolchain
+        run: |
+          rustup update --no-self-update stable
+          rustup target add ${{ env.targets }} ${{ env.targets_ide }}
 
-    - name: Cache Dependencies
-      uses: Swatinem/rust-cache@ce325b60658c1b38465c06cc965b79baf32c1e72
+      - name: Cache Dependencies
+        uses: Swatinem/rust-cache@ce325b60658c1b38465c06cc965b79baf32c1e72
 
-    - name: Check
-      run: |
-        for target in ${{ env.targets }}; do
-          cargo check --target=$target --all-targets
-        done
-        for target in ${{ env.targets_ide }}; do
-          cargo check -p ide --target=$target --all-targets
-        done
+      - name: Check
+        run: |
+          for target in ${{ env.targets }}; do
+            cargo check --target=$target --all-targets
+          done
+          for target in ${{ env.targets_ide }}; do
+            cargo check -p ide --target=$target --all-targets
+          done
 
   typescript:
     if: github.repository == 'rust-lang/rust-analyzer'
@@ -95,47 +95,47 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
+      - name: Checkout repository
+        uses: actions/checkout@v3
 
-    - name: Install Nodejs
-      uses: actions/setup-node@v1
-      with:
-        node-version: 16.x
+      - name: Install Nodejs
+        uses: actions/setup-node@v1
+        with:
+          node-version: 16.x
 
-    - name: Install xvfb
-      if: matrix.os == 'ubuntu-latest'
-      run: sudo apt-get install -y xvfb
+      - name: Install xvfb
+        if: matrix.os == 'ubuntu-latest'
+        run: sudo apt-get install -y xvfb
 
-    - run: npm ci
-      working-directory: ./editors/code
+      - run: npm ci
+        working-directory: ./editors/code
 
-#    - run: npm audit || { sleep 10 && npm audit; } || { sleep 30 && npm audit; }
-#      if: runner.os == 'Linux'
-#      working-directory: ./editors/code
+      #    - run: npm audit || { sleep 10 && npm audit; } || { sleep 30 && npm audit; }
+      #      if: runner.os == 'Linux'
+      #      working-directory: ./editors/code
 
-    - run: npm run lint
-      working-directory: ./editors/code
+      - run: npm run lint
+        working-directory: ./editors/code
 
-    - name: Run VS Code tests (Linux)
-      if: matrix.os == 'ubuntu-latest'
-      env:
-        VSCODE_CLI: 1
-      run: xvfb-run npm test
-      working-directory: ./editors/code
+      - name: Run VS Code tests (Linux)
+        if: matrix.os == 'ubuntu-latest'
+        env:
+          VSCODE_CLI: 1
+        run: xvfb-run npm test
+        working-directory: ./editors/code
 
-    - name: Run VS Code tests (Windows)
-      if: matrix.os == 'windows-latest'
-      env:
-        VSCODE_CLI: 1
-      run: npm test
-      working-directory: ./editors/code
+      - name: Run VS Code tests (Windows)
+        if: matrix.os == 'windows-latest'
+        env:
+          VSCODE_CLI: 1
+        run: npm test
+        working-directory: ./editors/code
 
-    - run: npm run pretest
-      working-directory: ./editors/code
+      - run: npm run pretest
+        working-directory: ./editors/code
 
-    - run: npm run package --scripts-prepend-node-path
-      working-directory: ./editors/code
+      - run: npm run package --scripts-prepend-node-path
+        working-directory: ./editors/code
 
   end-success:
     name: bors build finished
diff --git a/src/tools/rust-analyzer/.github/workflows/release.yaml b/src/tools/rust-analyzer/.github/workflows/release.yaml
index b2e5db6f689b..f4d472e3d5c1 100644
--- a/src/tools/rust-analyzer/.github/workflows/release.yaml
+++ b/src/tools/rust-analyzer/.github/workflows/release.yaml
@@ -34,6 +34,7 @@ jobs:
           - os: ubuntu-20.04
             target: x86_64-unknown-linux-gnu
             code-target: linux-x64
+            container: ubuntu:18.04
           - os: ubuntu-20.04
             target: aarch64-unknown-linux-gnu
             code-target: linux-arm64
@@ -49,6 +50,7 @@ jobs:
 
     name: dist (${{ matrix.target }})
     runs-on: ${{ matrix.os }}
+    container: ${{ matrix.container }}
 
     env:
       RA_TARGET: ${{ matrix.target }}
@@ -59,6 +61,14 @@ jobs:
         with:
           fetch-depth: ${{ env.FETCH_DEPTH }}
 
+      - name: Install toolchain dependencies
+        if: matrix.container == 'ubuntu:18.04'
+        shell: bash
+        run: |
+          apt-get update && apt-get install -y build-essential curl
+          curl --proto '=https' --tlsv1.2 --retry 10 --retry-connrefused -fsSL "https://sh.rustup.rs" | sh -s -- --profile minimal --default-toolchain none -y
+          echo "${CARGO_HOME:-$HOME/.cargo}/bin" >> $GITHUB_PATH
+
       - name: Install Rust toolchain
         run: |
           rustup update --no-self-update stable
@@ -248,7 +258,7 @@ jobs:
         if: github.ref == 'refs/heads/release' && (github.repository == 'rust-analyzer/rust-analyzer' || github.repository == 'rust-lang/rust-analyzer')
         working-directory: ./editors/code
         # token from https://dev.azure.com/rust-analyzer/
-        run: npx ovsx publish --pat ${{ secrets.OPENVSX_TOKEN }} --packagePath ../../dist/rust-analyzer-*.vsix
+        run: npx ovsx publish --pat ${{ secrets.OPENVSX_TOKEN }} --packagePath ../../dist/rust-analyzer-*.vsix || true
 
       - name: Publish Extension (Code Marketplace, nightly)
         if: github.ref != 'refs/heads/release' && (github.repository == 'rust-analyzer/rust-analyzer' || github.repository == 'rust-lang/rust-analyzer')
@@ -258,4 +268,4 @@ jobs:
       - name: Publish Extension (OpenVSX, nightly)
         if: github.ref != 'refs/heads/release' && (github.repository == 'rust-analyzer/rust-analyzer' || github.repository == 'rust-lang/rust-analyzer')
         working-directory: ./editors/code
-        run: npx ovsx publish --pat ${{ secrets.OPENVSX_TOKEN }} --packagePath ../../dist/rust-analyzer-*.vsix
+        run: npx ovsx publish --pat ${{ secrets.OPENVSX_TOKEN }} --packagePath ../../dist/rust-analyzer-*.vsix || true
diff --git a/src/tools/rust-analyzer/Cargo.lock b/src/tools/rust-analyzer/Cargo.lock
index 9f10d92c4e3a..216cf51447fa 100644
--- a/src/tools/rust-analyzer/Cargo.lock
+++ b/src/tools/rust-analyzer/Cargo.lock
@@ -394,6 +394,7 @@ dependencies = [
  "crossbeam-channel",
  "jod-thread",
  "paths",
+ "rustc-hash",
  "serde",
  "serde_json",
  "stdx",
@@ -660,6 +661,7 @@ dependencies = [
  "indexmap",
  "itertools",
  "limit",
+ "memchr",
  "once_cell",
  "parser",
  "profile",
diff --git a/src/tools/rust-analyzer/crates/flycheck/Cargo.toml b/src/tools/rust-analyzer/crates/flycheck/Cargo.toml
index d3d180ece512..688e790c5368 100644
--- a/src/tools/rust-analyzer/crates/flycheck/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/flycheck/Cargo.toml
@@ -13,6 +13,7 @@ doctest = false
 crossbeam-channel = "0.5.5"
 tracing = "0.1.35"
 cargo_metadata = "0.15.0"
+rustc-hash = "1.1.0"
 serde = { version = "1.0.137", features = ["derive"] }
 serde_json = "1.0.81"
 jod-thread = "0.1.2"
diff --git a/src/tools/rust-analyzer/crates/flycheck/src/lib.rs b/src/tools/rust-analyzer/crates/flycheck/src/lib.rs
index d9f4ef5b7ff5..fdc03f4053a2 100644
--- a/src/tools/rust-analyzer/crates/flycheck/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/flycheck/src/lib.rs
@@ -12,6 +12,7 @@ use std::{
 
 use crossbeam_channel::{never, select, unbounded, Receiver, Sender};
 use paths::AbsPathBuf;
+use rustc_hash::FxHashMap;
 use serde::Deserialize;
 use stdx::{process::streaming_output, JodChild};
 
@@ -30,10 +31,12 @@ pub enum FlycheckConfig {
         all_features: bool,
         features: Vec<String>,
         extra_args: Vec<String>,
+        extra_env: FxHashMap<String, String>,
     },
     CustomCommand {
         command: String,
         args: Vec<String>,
+        extra_env: FxHashMap<String, String>,
     },
 }
 
@@ -41,7 +44,7 @@ impl fmt::Display for FlycheckConfig {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             FlycheckConfig::CargoCommand { command, .. } => write!(f, "cargo {}", command),
-            FlycheckConfig::CustomCommand { command, args } => {
+            FlycheckConfig::CustomCommand { command, args, .. } => {
                 write!(f, "{} {}", command, args.join(" "))
             }
         }
@@ -256,6 +259,7 @@ impl FlycheckActor {
                 all_features,
                 extra_args,
                 features,
+                extra_env,
             } => {
                 let mut cmd = Command::new(toolchain::cargo());
                 cmd.arg(command);
@@ -281,11 +285,13 @@ impl FlycheckActor {
                     }
                 }
                 cmd.args(extra_args);
+                cmd.envs(extra_env);
                 cmd
             }
-            FlycheckConfig::CustomCommand { command, args } => {
+            FlycheckConfig::CustomCommand { command, args, extra_env } => {
                 let mut cmd = Command::new(command);
                 cmd.args(args);
+                cmd.envs(extra_env);
                 cmd
             }
         };
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/body.rs b/src/tools/rust-analyzer/crates/hir-def/src/body.rs
index 1d818d96267c..22f5fb992663 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/body.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/body.rs
@@ -250,6 +250,10 @@ pub type PatSource = InFile<PatPtr>;
 
 pub type LabelPtr = AstPtr<ast::Label>;
 pub type LabelSource = InFile<LabelPtr>;
+
+pub type FieldPtr = AstPtr<ast::RecordExprField>;
+pub type FieldSource = InFile<FieldPtr>;
+
 /// An item body together with the mapping from syntax nodes to HIR expression
 /// IDs. This is needed to go from e.g. a position in a file to the HIR
 /// expression containing it; but for type inference etc., we want to operate on
@@ -264,18 +268,18 @@ pub type LabelSource = InFile<LabelPtr>;
 #[derive(Default, Debug, Eq, PartialEq)]
 pub struct BodySourceMap {
     expr_map: FxHashMap<ExprSource, ExprId>,
-    expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
+    expr_map_back: ArenaMap<ExprId, ExprSource>,
 
     pat_map: FxHashMap<PatSource, PatId>,
-    pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
+    pat_map_back: ArenaMap<PatId, PatSource>,
 
     label_map: FxHashMap<LabelSource, LabelId>,
     label_map_back: ArenaMap<LabelId, LabelSource>,
 
     /// We don't create explicit nodes for record fields (`S { record_field: 92 }`).
     /// Instead, we use id of expression (`92`) to identify the field.
-    field_map: FxHashMap<InFile<AstPtr<ast::RecordExprField>>, ExprId>,
-    field_map_back: FxHashMap<ExprId, InFile<AstPtr<ast::RecordExprField>>>,
+    field_map: FxHashMap<FieldSource, ExprId>,
+    field_map_back: FxHashMap<ExprId, FieldSource>,
 
     expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
 
@@ -420,7 +424,7 @@ impl Index<LabelId> for Body {
 // Perhaps `expr_syntax` and `expr_id`?
 impl BodySourceMap {
     pub fn expr_syntax(&self, expr: ExprId) -> Result<ExprSource, SyntheticSyntax> {
-        self.expr_map_back[expr].clone()
+        self.expr_map_back.get(expr).cloned().ok_or(SyntheticSyntax)
     }
 
     pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
@@ -434,7 +438,7 @@ impl BodySourceMap {
     }
 
     pub fn pat_syntax(&self, pat: PatId) -> Result<PatSource, SyntheticSyntax> {
-        self.pat_map_back[pat].clone()
+        self.pat_map_back.get(pat).cloned().ok_or(SyntheticSyntax)
     }
 
     pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
@@ -456,9 +460,10 @@ impl BodySourceMap {
         self.label_map.get(&src).cloned()
     }
 
-    pub fn field_syntax(&self, expr: ExprId) -> InFile<AstPtr<ast::RecordExprField>> {
+    pub fn field_syntax(&self, expr: ExprId) -> FieldSource {
         self.field_map_back[&expr].clone()
     }
+
     pub fn node_field(&self, node: InFile<&ast::RecordExprField>) -> Option<ExprId> {
         let src = node.map(AstPtr::new);
         self.field_map.get(&src).cloned()
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/body/lower.rs b/src/tools/rust-analyzer/crates/hir-def/src/body/lower.rs
index f6ec8bf7e9e0..3b3297f7811c 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/body/lower.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/body/lower.rs
@@ -24,7 +24,7 @@ use syntax::{
 
 use crate::{
     adt::StructKind,
-    body::{Body, BodySourceMap, Expander, LabelSource, PatPtr, SyntheticSyntax},
+    body::{Body, BodySourceMap, Expander, ExprPtr, LabelPtr, LabelSource, PatPtr},
     body::{BodyDiagnostic, ExprSource, PatSource},
     builtin_type::{BuiltinFloat, BuiltinInt, BuiltinUint},
     db::DefDatabase,
@@ -150,21 +150,21 @@ impl ExprCollector<'_> {
         LowerCtx::new(self.db, self.expander.current_file_id)
     }
 
-    fn alloc_expr(&mut self, expr: Expr, ptr: AstPtr<ast::Expr>) -> ExprId {
+    fn alloc_expr(&mut self, expr: Expr, ptr: ExprPtr) -> ExprId {
         let src = self.expander.to_source(ptr);
-        let id = self.make_expr(expr, Ok(src.clone()));
+        let id = self.make_expr(expr, src.clone());
         self.source_map.expr_map.insert(src, id);
         id
     }
     // desugared exprs don't have ptr, that's wrong and should be fixed
     // somehow.
     fn alloc_expr_desugared(&mut self, expr: Expr) -> ExprId {
-        self.make_expr(expr, Err(SyntheticSyntax))
+        self.body.exprs.alloc(expr)
     }
     fn missing_expr(&mut self) -> ExprId {
         self.alloc_expr_desugared(Expr::Missing)
     }
-    fn make_expr(&mut self, expr: Expr, src: Result<ExprSource, SyntheticSyntax>) -> ExprId {
+    fn make_expr(&mut self, expr: Expr, src: ExprSource) -> ExprId {
         let id = self.body.exprs.alloc(expr);
         self.source_map.expr_map_back.insert(id, src);
         id
@@ -172,20 +172,20 @@ impl ExprCollector<'_> {
 
     fn alloc_pat(&mut self, pat: Pat, ptr: PatPtr) -> PatId {
         let src = self.expander.to_source(ptr);
-        let id = self.make_pat(pat, Ok(src.clone()));
+        let id = self.make_pat(pat, src.clone());
         self.source_map.pat_map.insert(src, id);
         id
     }
     fn missing_pat(&mut self) -> PatId {
-        self.make_pat(Pat::Missing, Err(SyntheticSyntax))
+        self.body.pats.alloc(Pat::Missing)
     }
-    fn make_pat(&mut self, pat: Pat, src: Result<PatSource, SyntheticSyntax>) -> PatId {
+    fn make_pat(&mut self, pat: Pat, src: PatSource) -> PatId {
         let id = self.body.pats.alloc(pat);
         self.source_map.pat_map_back.insert(id, src);
         id
     }
 
-    fn alloc_label(&mut self, label: Label, ptr: AstPtr<ast::Label>) -> LabelId {
+    fn alloc_label(&mut self, label: Label, ptr: LabelPtr) -> LabelId {
         let src = self.expander.to_source(ptr);
         let id = self.make_label(label, src.clone());
         self.source_map.label_map.insert(src, id);
@@ -550,20 +550,6 @@ impl ExprCollector<'_> {
                     None => self.alloc_expr(Expr::Missing, syntax_ptr),
                 }
             }
-            ast::Expr::MacroStmts(e) => {
-                let statements: Box<[_]> =
-                    e.statements().filter_map(|s| self.collect_stmt(s)).collect();
-                let tail = e.expr().map(|e| self.collect_expr(e));
-
-                if e.syntax().children().next().is_none() {
-                    // HACK: make sure that macros that expand to nothing aren't treated as a `()`
-                    // expression when used in block tail position.
-                    cov_mark::hit!(empty_macro_in_trailing_position_is_removed);
-                    return None;
-                }
-
-                self.alloc_expr(Expr::MacroStmts { tail, statements }, syntax_ptr)
-            }
             ast::Expr::UnderscoreExpr(_) => self.alloc_expr(Expr::Underscore, syntax_ptr),
         })
     }
@@ -640,11 +626,46 @@ impl ExprCollector<'_> {
         }
     }
 
-    fn collect_stmt(&mut self, s: ast::Stmt) -> Option<Statement> {
+    fn collect_macro_as_stmt(
+        &mut self,
+        statements: &mut Vec<Statement>,
+        mac: ast::MacroExpr,
+    ) -> Option<ExprId> {
+        let mac_call = mac.macro_call()?;
+        let syntax_ptr = AstPtr::new(&ast::Expr::from(mac));
+        let macro_ptr = AstPtr::new(&mac_call);
+        let expansion = self.collect_macro_call(
+            mac_call,
+            macro_ptr,
+            false,
+            |this, expansion: Option<ast::MacroStmts>| match expansion {
+                Some(expansion) => {
+                    expansion.statements().for_each(|stmt| this.collect_stmt(statements, stmt));
+                    expansion.expr().and_then(|expr| match expr {
+                        ast::Expr::MacroExpr(mac) => this.collect_macro_as_stmt(statements, mac),
+                        expr => Some(this.collect_expr(expr)),
+                    })
+                }
+                None => None,
+            },
+        );
+        match expansion {
+            Some(tail) => {
+                // Make the macro-call point to its expanded expression so we can query
+                // semantics on syntax pointers to the macro
+                let src = self.expander.to_source(syntax_ptr);
+                self.source_map.expr_map.insert(src, tail);
+                Some(tail)
+            }
+            None => None,
+        }
+    }
+
+    fn collect_stmt(&mut self, statements: &mut Vec<Statement>, s: ast::Stmt) {
         match s {
             ast::Stmt::LetStmt(stmt) => {
                 if self.check_cfg(&stmt).is_none() {
-                    return None;
+                    return;
                 }
                 let pat = self.collect_pat_opt(stmt.pat());
                 let type_ref =
@@ -654,61 +675,26 @@ impl ExprCollector<'_> {
                     .let_else()
                     .and_then(|let_else| let_else.block_expr())
                     .map(|block| self.collect_block(block));
-                Some(Statement::Let { pat, type_ref, initializer, else_branch })
+                statements.push(Statement::Let { pat, type_ref, initializer, else_branch });
             }
             ast::Stmt::ExprStmt(stmt) => {
                 let expr = stmt.expr();
-                if let Some(expr) = &expr {
-                    if self.check_cfg(expr).is_none() {
-                        return None;
-                    }
+                match &expr {
+                    Some(expr) if self.check_cfg(expr).is_none() => return,
+                    _ => (),
                 }
                 let has_semi = stmt.semicolon_token().is_some();
                 // Note that macro could be expanded to multiple statements
-                if let Some(expr @ ast::Expr::MacroExpr(mac)) = &expr {
-                    let mac_call = mac.macro_call()?;
-                    let syntax_ptr = AstPtr::new(expr);
-                    let macro_ptr = AstPtr::new(&mac_call);
-                    let stmt = self.collect_macro_call(
-                        mac_call,
-                        macro_ptr,
-                        false,
-                        |this, expansion: Option<ast::MacroStmts>| match expansion {
-                            Some(expansion) => {
-                                let statements = expansion
-                                    .statements()
-                                    .filter_map(|stmt| this.collect_stmt(stmt))
-                                    .collect();
-                                let tail = expansion.expr().map(|expr| this.collect_expr(expr));
-
-                                let mac_stmts = this.alloc_expr(
-                                    Expr::MacroStmts { tail, statements },
-                                    AstPtr::new(&ast::Expr::MacroStmts(expansion)),
-                                );
-
-                                Some(mac_stmts)
-                            }
-                            None => None,
-                        },
-                    );
-
-                    let expr = match stmt {
-                        Some(expr) => {
-                            // Make the macro-call point to its expanded expression so we can query
-                            // semantics on syntax pointers to the macro
-                            let src = self.expander.to_source(syntax_ptr);
-                            self.source_map.expr_map.insert(src, expr);
-                            expr
-                        }
-                        None => self.alloc_expr(Expr::Missing, syntax_ptr),
-                    };
-                    Some(Statement::Expr { expr, has_semi })
+                if let Some(ast::Expr::MacroExpr(mac)) = expr {
+                    if let Some(expr) = self.collect_macro_as_stmt(statements, mac) {
+                        statements.push(Statement::Expr { expr, has_semi })
+                    }
                 } else {
                     let expr = self.collect_expr_opt(expr);
-                    Some(Statement::Expr { expr, has_semi })
+                    statements.push(Statement::Expr { expr, has_semi });
                 }
             }
-            ast::Stmt::Item(_item) => None,
+            ast::Stmt::Item(_item) => (),
         }
     }
 
@@ -729,9 +715,12 @@ impl ExprCollector<'_> {
         let prev_def_map = mem::replace(&mut self.expander.def_map, def_map);
         let prev_local_module = mem::replace(&mut self.expander.module, module);
 
-        let mut statements: Vec<_> =
-            block.statements().filter_map(|s| self.collect_stmt(s)).collect();
-        let tail = block.tail_expr().and_then(|e| self.maybe_collect_expr(e));
+        let mut statements = Vec::new();
+        block.statements().for_each(|s| self.collect_stmt(&mut statements, s));
+        let tail = block.tail_expr().and_then(|e| match e {
+            ast::Expr::MacroExpr(mac) => self.collect_macro_as_stmt(&mut statements, mac),
+            expr => self.maybe_collect_expr(expr),
+        });
         let tail = tail.or_else(|| {
             let stmt = statements.pop()?;
             if let Statement::Expr { expr, has_semi: false } = stmt {
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/body/pretty.rs b/src/tools/rust-analyzer/crates/hir-def/src/body/pretty.rs
index ddd476efe5c4..f2fed954444e 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/body/pretty.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/body/pretty.rs
@@ -422,19 +422,6 @@ impl<'a> Printer<'a> {
                 }
                 w!(self, "}}");
             }
-            Expr::MacroStmts { statements, tail } => {
-                w!(self, "{{ // macro statements");
-                self.indented(|p| {
-                    for stmt in statements.iter() {
-                        p.print_stmt(stmt);
-                    }
-                    if let Some(tail) = tail {
-                        p.print_expr(*tail);
-                    }
-                });
-                self.newline();
-                w!(self, "}}");
-            }
         }
     }
 
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/body/scope.rs b/src/tools/rust-analyzer/crates/hir-def/src/body/scope.rs
index f4c390dce26e..45f64ebb0600 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/body/scope.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/body/scope.rs
@@ -47,16 +47,9 @@ pub struct ScopeData {
 impl ExprScopes {
     pub(crate) fn expr_scopes_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<ExprScopes> {
         let body = db.body(def);
-        Arc::new(ExprScopes::new(&*body))
-    }
-
-    fn new(body: &Body) -> ExprScopes {
-        let mut scopes =
-            ExprScopes { scopes: Arena::default(), scope_by_expr: FxHashMap::default() };
-        let mut root = scopes.root_scope();
-        scopes.add_params_bindings(body, root, &body.params);
-        compute_expr_scopes(body.body_expr, body, &mut scopes, &mut root);
-        scopes
+        let mut scopes = ExprScopes::new(&*body);
+        scopes.shrink_to_fit();
+        Arc::new(scopes)
     }
 
     pub fn entries(&self, scope: ScopeId) -> &[ScopeEntry] {
@@ -89,6 +82,17 @@ impl ExprScopes {
     pub fn scope_by_expr(&self) -> &FxHashMap<ExprId, ScopeId> {
         &self.scope_by_expr
     }
+}
+
+impl ExprScopes {
+    fn new(body: &Body) -> ExprScopes {
+        let mut scopes =
+            ExprScopes { scopes: Arena::default(), scope_by_expr: FxHashMap::default() };
+        let mut root = scopes.root_scope();
+        scopes.add_params_bindings(body, root, &body.params);
+        compute_expr_scopes(body.body_expr, body, &mut scopes, &mut root);
+        scopes
+    }
 
     fn root_scope(&mut self) -> ScopeId {
         self.scopes.alloc(ScopeData { parent: None, block: None, label: None, entries: vec![] })
@@ -138,6 +142,13 @@ impl ExprScopes {
     fn set_scope(&mut self, node: ExprId, scope: ScopeId) {
         self.scope_by_expr.insert(node, scope);
     }
+
+    fn shrink_to_fit(&mut self) {
+        let ExprScopes { scopes, scope_by_expr } = self;
+        scopes.shrink_to_fit();
+        scopes.values_mut().for_each(|it| it.entries.shrink_to_fit());
+        scope_by_expr.shrink_to_fit();
+    }
 }
 
 fn compute_block_scopes(
@@ -176,9 +187,6 @@ fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut ExprScopes, scope
 
     scopes.set_scope(expr, *scope);
     match &body[expr] {
-        Expr::MacroStmts { statements, tail } => {
-            compute_block_scopes(statements, *tail, body, scopes, scope);
-        }
         Expr::Block { statements, tail, id, label } => {
             let mut scope = scopes.new_block_scope(*scope, *id, make_label(label));
             // Overwrite the old scope for the block expr, so that every block scope can be found
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/expr.rs b/src/tools/rust-analyzer/crates/hir-def/src/expr.rs
index 4381b43c258b..419d3feec3b6 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/expr.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/expr.rs
@@ -206,10 +206,6 @@ pub enum Expr {
     Unsafe {
         body: ExprId,
     },
-    MacroStmts {
-        statements: Box<[Statement]>,
-        tail: Option<ExprId>,
-    },
     Array(Array),
     Literal(Literal),
     Underscore,
@@ -263,7 +259,7 @@ impl Expr {
             Expr::Let { expr, .. } => {
                 f(*expr);
             }
-            Expr::MacroStmts { tail, statements } | Expr::Block { statements, tail, .. } => {
+            Expr::Block { statements, tail, .. } => {
                 for stmt in statements.iter() {
                     match stmt {
                         Statement::Let { initializer, .. } => {
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/find_path.rs b/src/tools/rust-analyzer/crates/hir-def/src/find_path.rs
index 89e961f84fad..b94b50004093 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/find_path.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/find_path.rs
@@ -1,6 +1,6 @@
 //! An algorithm to find a path to refer to a certain item.
 
-use std::iter;
+use std::{cmp::Ordering, iter};
 
 use hir_expand::name::{known, AsName, Name};
 use rustc_hash::FxHashSet;
@@ -16,9 +16,14 @@ use crate::{
 
 /// Find a path that can be used to refer to a certain item. This can depend on
 /// *from where* you're referring to the item, hence the `from` parameter.
-pub fn find_path(db: &dyn DefDatabase, item: ItemInNs, from: ModuleId) -> Option<ModPath> {
+pub fn find_path(
+    db: &dyn DefDatabase,
+    item: ItemInNs,
+    from: ModuleId,
+    prefer_no_std: bool,
+) -> Option<ModPath> {
     let _p = profile::span("find_path");
-    find_path_inner(db, item, from, None)
+    find_path_inner(db, item, from, None, prefer_no_std)
 }
 
 pub fn find_path_prefixed(
@@ -26,47 +31,14 @@ pub fn find_path_prefixed(
     item: ItemInNs,
     from: ModuleId,
     prefix_kind: PrefixKind,
+    prefer_no_std: bool,
 ) -> Option<ModPath> {
     let _p = profile::span("find_path_prefixed");
-    find_path_inner(db, item, from, Some(prefix_kind))
+    find_path_inner(db, item, from, Some(prefix_kind), prefer_no_std)
 }
 
 const MAX_PATH_LEN: usize = 15;
 
-trait ModPathExt {
-    fn starts_with_std(&self) -> bool;
-    fn can_start_with_std(&self) -> bool;
-}
-
-impl ModPathExt for ModPath {
-    fn starts_with_std(&self) -> bool {
-        self.segments().first() == Some(&known::std)
-    }
-
-    // Can we replace the first segment with `std::` and still get a valid, identical path?
-    fn can_start_with_std(&self) -> bool {
-        let first_segment = self.segments().first();
-        first_segment == Some(&known::alloc) || first_segment == Some(&known::core)
-    }
-}
-
-fn check_self_super(def_map: &DefMap, item: ItemInNs, from: ModuleId) -> Option<ModPath> {
-    if item == ItemInNs::Types(from.into()) {
-        // - if the item is the module we're in, use `self`
-        Some(ModPath::from_segments(PathKind::Super(0), None))
-    } else if let Some(parent_id) = def_map[from.local_id].parent {
-        // - if the item is the parent module, use `super` (this is not used recursively, since `super::super` is ugly)
-        let parent_id = def_map.module_id(parent_id);
-        if item == ItemInNs::Types(ModuleDefId::ModuleId(parent_id)) {
-            Some(ModPath::from_segments(PathKind::Super(1), None))
-        } else {
-            None
-        }
-    } else {
-        None
-    }
-}
-
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum PrefixKind {
     /// Causes paths to always start with either `self`, `super`, `crate` or a crate-name.
@@ -94,104 +66,60 @@ impl PrefixKind {
         self == &PrefixKind::ByCrate
     }
 }
+
 /// Attempts to find a path to refer to the given `item` visible from the `from` ModuleId
 fn find_path_inner(
     db: &dyn DefDatabase,
     item: ItemInNs,
     from: ModuleId,
     prefixed: Option<PrefixKind>,
+    prefer_no_std: bool,
 ) -> Option<ModPath> {
-    // FIXME: Do fast path for std/core libs?
-
-    let mut visited_modules = FxHashSet::default();
-    let def_map = from.def_map(db);
-    find_path_inner_(db, &def_map, from, item, MAX_PATH_LEN, prefixed, &mut visited_modules)
-}
-
-fn find_path_inner_(
-    db: &dyn DefDatabase,
-    def_map: &DefMap,
-    from: ModuleId,
-    item: ItemInNs,
-    max_len: usize,
-    mut prefixed: Option<PrefixKind>,
-    visited_modules: &mut FxHashSet<ModuleId>,
-) -> Option<ModPath> {
-    if max_len == 0 {
-        return None;
+    // - if the item is a builtin, it's in scope
+    if let ItemInNs::Types(ModuleDefId::BuiltinType(builtin)) = item {
+        return Some(ModPath::from_segments(PathKind::Plain, Some(builtin.as_name())));
     }
 
-    // Base cases:
+    let def_map = from.def_map(db);
+    let crate_root = def_map.crate_root(db);
+    // - if the item is a module, jump straight to module search
+    if let ItemInNs::Types(ModuleDefId::ModuleId(module_id)) = item {
+        let mut visited_modules = FxHashSet::default();
+        return find_path_for_module(
+            db,
+            &def_map,
+            &mut visited_modules,
+            crate_root,
+            from,
+            module_id,
+            MAX_PATH_LEN,
+            prefixed,
+            prefer_no_std || db.crate_supports_no_std(crate_root.krate),
+        );
+    }
 
     // - if the item is already in scope, return the name under which it is
-    let scope_name = def_map.with_ancestor_maps(db, from.local_id, &mut |def_map, local_id| {
-        def_map[local_id].scope.name_of(item).map(|(name, _)| name.clone())
-    });
+    let scope_name = find_in_scope(db, &def_map, from, item);
     if prefixed.is_none() {
         if let Some(scope_name) = scope_name {
             return Some(ModPath::from_segments(PathKind::Plain, Some(scope_name)));
         }
     }
 
-    // - if the item is a builtin, it's in scope
-    if let ItemInNs::Types(ModuleDefId::BuiltinType(builtin)) = item {
-        return Some(ModPath::from_segments(PathKind::Plain, Some(builtin.as_name())));
-    }
-
-    // - if the item is the crate root, return `crate`
-    let crate_root = def_map.crate_root(db);
-    if item == ItemInNs::Types(ModuleDefId::ModuleId(crate_root)) {
-        return Some(ModPath::from_segments(PathKind::Crate, None));
-    }
-
-    if prefixed.filter(PrefixKind::is_absolute).is_none() {
-        if let modpath @ Some(_) = check_self_super(&def_map, item, from) {
-            return modpath;
-        }
-    }
-
-    // - if the item is the crate root of a dependency crate, return the name from the extern prelude
-    let root_def_map = crate_root.def_map(db);
-    if let ItemInNs::Types(ModuleDefId::ModuleId(item)) = item {
-        for (name, &def_id) in root_def_map.extern_prelude() {
-            if item == def_id {
-                let name = scope_name.unwrap_or_else(|| name.clone());
-
-                let name_already_occupied_in_type_ns = def_map
-                    .with_ancestor_maps(db, from.local_id, &mut |def_map, local_id| {
-                        def_map[local_id]
-                            .scope
-                            .type_(&name)
-                            .filter(|&(id, _)| id != ModuleDefId::ModuleId(def_id))
-                    })
-                    .is_some();
-                let kind = if name_already_occupied_in_type_ns {
-                    cov_mark::hit!(ambiguous_crate_start);
-                    PathKind::Abs
-                } else {
-                    PathKind::Plain
-                };
-                return Some(ModPath::from_segments(kind, Some(name)));
-            }
-        }
-    }
-
     // - if the item is in the prelude, return the name from there
-    if let Some(prelude_module) = root_def_map.prelude() {
-        // Preludes in block DefMaps are ignored, only the crate DefMap is searched
-        let prelude_def_map = prelude_module.def_map(db);
-        let prelude_scope = &prelude_def_map[prelude_module.local_id].scope;
-        if let Some((name, vis)) = prelude_scope.name_of(item) {
-            if vis.is_visible_from(db, from) {
-                return Some(ModPath::from_segments(PathKind::Plain, Some(name.clone())));
-            }
-        }
+    if let Some(value) = find_in_prelude(db, &crate_root.def_map(db), item, from) {
+        return value;
     }
 
-    // Recursive case:
-    // - if the item is an enum variant, refer to it via the enum
     if let Some(ModuleDefId::EnumVariantId(variant)) = item.as_module_def_id() {
-        if let Some(mut path) = find_path(db, ItemInNs::Types(variant.parent.into()), from) {
+        // - if the item is an enum variant, refer to it via the enum
+        if let Some(mut path) = find_path_inner(
+            db,
+            ItemInNs::Types(variant.parent.into()),
+            from,
+            prefixed,
+            prefer_no_std,
+        ) {
             let data = db.enum_data(variant.parent);
             path.push_segment(data.variants[variant.local_id].name.clone());
             return Some(path);
@@ -201,28 +129,184 @@ fn find_path_inner_(
         // variant somewhere
     }
 
-    // - otherwise, look for modules containing (reexporting) it and import it from one of those
-    let prefer_no_std = db.crate_supports_no_std(crate_root.krate);
-    let mut best_path = None;
-    let mut best_path_len = max_len;
+    let mut visited_modules = FxHashSet::default();
 
+    calculate_best_path(
+        db,
+        &def_map,
+        &mut visited_modules,
+        crate_root,
+        MAX_PATH_LEN,
+        item,
+        from,
+        prefixed,
+        prefer_no_std || db.crate_supports_no_std(crate_root.krate),
+        scope_name,
+    )
+}
+
+fn find_path_for_module(
+    db: &dyn DefDatabase,
+    def_map: &DefMap,
+    visited_modules: &mut FxHashSet<ModuleId>,
+    crate_root: ModuleId,
+    from: ModuleId,
+    module_id: ModuleId,
+    max_len: usize,
+    prefixed: Option<PrefixKind>,
+    prefer_no_std: bool,
+) -> Option<ModPath> {
+    if max_len == 0 {
+        return None;
+    }
+
+    // Base cases:
+    // - if the item is already in scope, return the name under which it is
+    let scope_name = find_in_scope(db, def_map, from, ItemInNs::Types(module_id.into()));
+    if prefixed.is_none() {
+        if let Some(scope_name) = scope_name {
+            return Some(ModPath::from_segments(PathKind::Plain, Some(scope_name)));
+        }
+    }
+
+    // - if the item is the crate root, return `crate`
+    if module_id == crate_root {
+        return Some(ModPath::from_segments(PathKind::Crate, None));
+    }
+
+    // - if relative paths are fine, check if we are searching for a parent
+    if prefixed.filter(PrefixKind::is_absolute).is_none() {
+        if let modpath @ Some(_) = find_self_super(&def_map, module_id, from) {
+            return modpath;
+        }
+    }
+
+    // - if the item is the crate root of a dependency crate, return the name from the extern prelude
+    let root_def_map = crate_root.def_map(db);
+    for (name, &def_id) in root_def_map.extern_prelude() {
+        if module_id == def_id {
+            let name = scope_name.unwrap_or_else(|| name.clone());
+
+            let name_already_occupied_in_type_ns = def_map
+                .with_ancestor_maps(db, from.local_id, &mut |def_map, local_id| {
+                    def_map[local_id]
+                        .scope
+                        .type_(&name)
+                        .filter(|&(id, _)| id != ModuleDefId::ModuleId(def_id))
+                })
+                .is_some();
+            let kind = if name_already_occupied_in_type_ns {
+                cov_mark::hit!(ambiguous_crate_start);
+                PathKind::Abs
+            } else {
+                PathKind::Plain
+            };
+            return Some(ModPath::from_segments(kind, Some(name)));
+        }
+    }
+
+    if let Some(value) = find_in_prelude(db, &root_def_map, ItemInNs::Types(module_id.into()), from)
+    {
+        return value;
+    }
+    calculate_best_path(
+        db,
+        def_map,
+        visited_modules,
+        crate_root,
+        max_len,
+        ItemInNs::Types(module_id.into()),
+        from,
+        prefixed,
+        prefer_no_std,
+        scope_name,
+    )
+}
+
+fn find_in_scope(
+    db: &dyn DefDatabase,
+    def_map: &DefMap,
+    from: ModuleId,
+    item: ItemInNs,
+) -> Option<Name> {
+    def_map.with_ancestor_maps(db, from.local_id, &mut |def_map, local_id| {
+        def_map[local_id].scope.name_of(item).map(|(name, _)| name.clone())
+    })
+}
+
+fn find_in_prelude(
+    db: &dyn DefDatabase,
+    root_def_map: &DefMap,
+    item: ItemInNs,
+    from: ModuleId,
+) -> Option<Option<ModPath>> {
+    if let Some(prelude_module) = root_def_map.prelude() {
+        // Preludes in block DefMaps are ignored, only the crate DefMap is searched
+        let prelude_def_map = prelude_module.def_map(db);
+        let prelude_scope = &prelude_def_map[prelude_module.local_id].scope;
+        if let Some((name, vis)) = prelude_scope.name_of(item) {
+            if vis.is_visible_from(db, from) {
+                return Some(Some(ModPath::from_segments(PathKind::Plain, Some(name.clone()))));
+            }
+        }
+    }
+    None
+}
+
+fn find_self_super(def_map: &DefMap, item: ModuleId, from: ModuleId) -> Option<ModPath> {
+    if item == from {
+        // - if the item is the module we're in, use `self`
+        Some(ModPath::from_segments(PathKind::Super(0), None))
+    } else if let Some(parent_id) = def_map[from.local_id].parent {
+        // - if the item is the parent module, use `super` (this is not used recursively, since `super::super` is ugly)
+        let parent_id = def_map.module_id(parent_id);
+        if item == parent_id {
+            Some(ModPath::from_segments(PathKind::Super(1), None))
+        } else {
+            None
+        }
+    } else {
+        None
+    }
+}
+
+fn calculate_best_path(
+    db: &dyn DefDatabase,
+    def_map: &DefMap,
+    visited_modules: &mut FxHashSet<ModuleId>,
+    crate_root: ModuleId,
+    max_len: usize,
+    item: ItemInNs,
+    from: ModuleId,
+    mut prefixed: Option<PrefixKind>,
+    prefer_no_std: bool,
+    scope_name: Option<Name>,
+) -> Option<ModPath> {
+    if max_len <= 1 {
+        return None;
+    }
+    let mut best_path = None;
+    // Recursive case:
+    // - otherwise, look for modules containing (reexporting) it and import it from one of those
     if item.krate(db) == Some(from.krate) {
+        let mut best_path_len = max_len;
         // Item was defined in the same crate that wants to import it. It cannot be found in any
         // dependency in this case.
-        // FIXME: this should have a fast path that doesn't look through the prelude again?
         for (module_id, name) in find_local_import_locations(db, item, from) {
             if !visited_modules.insert(module_id) {
                 cov_mark::hit!(recursive_imports);
                 continue;
             }
-            if let Some(mut path) = find_path_inner_(
+            if let Some(mut path) = find_path_for_module(
                 db,
                 def_map,
+                visited_modules,
+                crate_root,
                 from,
-                ItemInNs::Types(ModuleDefId::ModuleId(module_id)),
+                module_id,
                 best_path_len - 1,
                 prefixed,
-                visited_modules,
+                prefer_no_std,
             ) {
                 path.push_segment(name);
 
@@ -245,14 +329,16 @@ fn find_path_inner_(
             import_map.import_info_for(item).and_then(|info| {
                 // Determine best path for containing module and append last segment from `info`.
                 // FIXME: we should guide this to look up the path locally, or from the same crate again?
-                let mut path = find_path_inner_(
+                let mut path = find_path_for_module(
                     db,
                     def_map,
-                    from,
-                    ItemInNs::Types(ModuleDefId::ModuleId(info.container)),
-                    best_path_len - 1,
-                    prefixed,
                     visited_modules,
+                    from,
+                    crate_root,
+                    info.container,
+                    max_len - 1,
+                    prefixed,
+                    prefer_no_std,
                 )?;
                 cov_mark::hit!(partially_imported);
                 path.push_segment(info.path.segments.last()?.clone());
@@ -268,16 +354,12 @@ fn find_path_inner_(
             best_path = Some(new_path);
         }
     }
-
-    // If the item is declared inside a block expression, don't use a prefix, as we don't handle
-    // that correctly (FIXME).
-    if let Some(item_module) = item.as_module_def_id().and_then(|did| did.module(db)) {
-        if item_module.def_map(db).block_id().is_some() && prefixed.is_some() {
+    if let Some(module) = item.module(db) {
+        if module.def_map(db).block_id().is_some() && prefixed.is_some() {
             cov_mark::hit!(prefixed_in_block_expression);
             prefixed = Some(PrefixKind::Plain);
         }
     }
-
     match prefixed.map(PrefixKind::prefix) {
         Some(prefix) => best_path.or_else(|| {
             scope_name.map(|scope_name| ModPath::from_segments(prefix, Some(scope_name)))
@@ -287,29 +369,48 @@ fn find_path_inner_(
 }
 
 fn select_best_path(old_path: ModPath, new_path: ModPath, prefer_no_std: bool) -> ModPath {
-    if old_path.starts_with_std() && new_path.can_start_with_std() {
-        if prefer_no_std {
-            cov_mark::hit!(prefer_no_std_paths);
-            new_path
-        } else {
-            cov_mark::hit!(prefer_std_paths);
-            old_path
+    const STD_CRATES: [Name; 3] = [known::std, known::core, known::alloc];
+    match (old_path.segments().first(), new_path.segments().first()) {
+        (Some(old), Some(new)) if STD_CRATES.contains(old) && STD_CRATES.contains(new) => {
+            let rank = match prefer_no_std {
+                false => |name: &Name| match name {
+                    name if name == &known::core => 0,
+                    name if name == &known::alloc => 0,
+                    name if name == &known::std => 1,
+                    _ => unreachable!(),
+                },
+                true => |name: &Name| match name {
+                    name if name == &known::core => 2,
+                    name if name == &known::alloc => 1,
+                    name if name == &known::std => 0,
+                    _ => unreachable!(),
+                },
+            };
+            let nrank = rank(new);
+            let orank = rank(old);
+            match nrank.cmp(&orank) {
+                Ordering::Less => old_path,
+                Ordering::Equal => {
+                    if new_path.len() < old_path.len() {
+                        new_path
+                    } else {
+                        old_path
+                    }
+                }
+                Ordering::Greater => new_path,
+            }
         }
-    } else if new_path.starts_with_std() && old_path.can_start_with_std() {
-        if prefer_no_std {
-            cov_mark::hit!(prefer_no_std_paths);
-            old_path
-        } else {
-            cov_mark::hit!(prefer_std_paths);
-            new_path
+        _ => {
+            if new_path.len() < old_path.len() {
+                new_path
+            } else {
+                old_path
+            }
         }
-    } else if new_path.len() < old_path.len() {
-        new_path
-    } else {
-        old_path
     }
 }
 
+// FIXME: Remove allocations
 /// Finds locations in `from.krate` from which `item` can be imported by `from`.
 fn find_local_import_locations(
     db: &dyn DefDatabase,
@@ -428,7 +529,8 @@ mod tests {
             .take_types()
             .unwrap();
 
-        let found_path = find_path_inner(&db, ItemInNs::Types(resolved), module, prefix_kind);
+        let found_path =
+            find_path_inner(&db, ItemInNs::Types(resolved), module, prefix_kind, false);
         assert_eq!(found_path, Some(mod_path), "{:?}", prefix_kind);
     }
 
@@ -468,8 +570,8 @@ $0
         "#,
             "E::A",
             "E::A",
-            "E::A",
-            "E::A",
+            "crate::E::A",
+            "self::E::A",
         );
     }
 
@@ -788,7 +890,6 @@ pub use super::foo;
 
     #[test]
     fn prefer_std_paths_over_alloc() {
-        cov_mark::check!(prefer_std_paths);
         check_found_path(
             r#"
 //- /main.rs crate:main deps:alloc,std
@@ -813,7 +914,6 @@ pub mod sync {
 
     #[test]
     fn prefer_core_paths_over_std() {
-        cov_mark::check!(prefer_no_std_paths);
         check_found_path(
             r#"
 //- /main.rs crate:main deps:core,std
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/item_scope.rs b/src/tools/rust-analyzer/crates/hir-def/src/item_scope.rs
index a11a92204c15..7721221c4447 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/item_scope.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/item_scope.rs
@@ -18,7 +18,7 @@ use crate::{
     ConstId, HasModule, ImplId, LocalModuleId, MacroId, ModuleDefId, ModuleId, TraitId,
 };
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub(crate) enum ImportType {
     Glob,
     Named,
@@ -302,13 +302,13 @@ impl ItemScope {
                             $changed = true;
                         }
                         Entry::Occupied(mut entry)
-                            if $glob_imports.$field.contains(&$lookup)
-                                && matches!($def_import_type, ImportType::Named) =>
+                            if matches!($def_import_type, ImportType::Named) =>
                         {
-                            cov_mark::hit!(import_shadowed);
-                            $glob_imports.$field.remove(&$lookup);
-                            entry.insert(fld);
-                            $changed = true;
+                            if $glob_imports.$field.remove(&$lookup) {
+                                cov_mark::hit!(import_shadowed);
+                                entry.insert(fld);
+                                $changed = true;
+                            }
                         }
                         _ => {}
                     }
@@ -457,8 +457,15 @@ impl ItemInNs {
     /// Returns the crate defining this item (or `None` if `self` is built-in).
     pub fn krate(&self, db: &dyn DefDatabase) -> Option<CrateId> {
         match self {
-            ItemInNs::Types(did) | ItemInNs::Values(did) => did.module(db).map(|m| m.krate),
+            ItemInNs::Types(id) | ItemInNs::Values(id) => id.module(db).map(|m| m.krate),
             ItemInNs::Macros(id) => Some(id.module(db).krate),
         }
     }
+
+    pub fn module(&self, db: &dyn DefDatabase) -> Option<ModuleId> {
+        match self {
+            ItemInNs::Types(id) | ItemInNs::Values(id) => id.module(db),
+            ItemInNs::Macros(id) => Some(id.module(db)),
+        }
+    }
 }
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/nameres.rs b/src/tools/rust-analyzer/crates/hir-def/src/nameres.rs
index 6eb530ecc542..9b4ce9f97c86 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/nameres.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/nameres.rs
@@ -64,7 +64,7 @@ use hir_expand::{name::Name, InFile, MacroCallId, MacroDefId};
 use itertools::Itertools;
 use la_arena::Arena;
 use profile::Count;
-use rustc_hash::FxHashMap;
+use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::format_to;
 use syntax::{ast, SmolStr};
 
@@ -98,7 +98,11 @@ pub struct DefMap {
     /// The prelude module for this crate. This either comes from an import
     /// marked with the `prelude_import` attribute, or (in the normal case) from
     /// a dependency (`std` or `core`).
+    /// The prelude is empty for non-block DefMaps (unless `#[prelude_import]` was used,
+    /// but that attribute is nightly and when used in a block, it affects resolution globally
+    /// so we aren't handling this correctly anyways).
     prelude: Option<ModuleId>,
+    /// The extern prelude is only populated for non-block DefMaps
     extern_prelude: FxHashMap<Name, ModuleId>,
 
     /// Side table for resolving derive helpers.
@@ -114,6 +118,8 @@ pub struct DefMap {
     registered_attrs: Vec<SmolStr>,
     /// Custom tool modules registered with `#![register_tool]`.
     registered_tools: Vec<SmolStr>,
+    /// Unstable features of Rust enabled with `#![feature(A, B)]`.
+    unstable_features: FxHashSet<SmolStr>,
 
     edition: Edition,
     recursion_limit: Option<u32>,
@@ -284,6 +290,7 @@ impl DefMap {
             modules,
             registered_attrs: Vec::new(),
             registered_tools: Vec::new(),
+            unstable_features: FxHashSet::default(),
             diagnostics: Vec::new(),
         }
     }
@@ -314,6 +321,10 @@ impl DefMap {
         &self.registered_attrs
     }
 
+    pub fn is_unstable_feature_enabled(&self, feature: &str) -> bool {
+        self.unstable_features.contains(feature)
+    }
+
     pub fn root(&self) -> LocalModuleId {
         self.root
     }
@@ -479,6 +490,7 @@ impl DefMap {
             registered_tools,
             fn_proc_macro_mapping,
             derive_helpers_in_scope,
+            unstable_features,
             proc_macro_loading_error: _,
             block: _,
             edition: _,
@@ -496,6 +508,7 @@ impl DefMap {
         registered_tools.shrink_to_fit();
         fn_proc_macro_mapping.shrink_to_fit();
         derive_helpers_in_scope.shrink_to_fit();
+        unstable_features.shrink_to_fit();
         for (_, module) in modules.iter_mut() {
             module.children.shrink_to_fit();
             module.scope.shrink_to_fit();
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/nameres/collector.rs b/src/tools/rust-analyzer/crates/hir-def/src/nameres/collector.rs
index 8a6bb929c3df..9242b48c5931 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/nameres/collector.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/nameres/collector.rs
@@ -294,6 +294,17 @@ impl DefCollector<'_> {
                     continue;
                 }
 
+                if *attr_name == hir_expand::name![feature] {
+                    let features =
+                        attr.parse_path_comma_token_tree().into_iter().flatten().filter_map(
+                            |feat| match feat.segments() {
+                                [name] => Some(name.to_smol_str()),
+                                _ => None,
+                            },
+                        );
+                    self.def_map.unstable_features.extend(features);
+                }
+
                 let attr_is_register_like = *attr_name == hir_expand::name![register_attr]
                     || *attr_name == hir_expand::name![register_tool];
                 if !attr_is_register_like {
@@ -501,10 +512,9 @@ impl DefCollector<'_> {
             Edition::Edition2021 => name![rust_2021],
         };
 
-        let path_kind = if self.def_map.edition == Edition::Edition2015 {
-            PathKind::Plain
-        } else {
-            PathKind::Abs
+        let path_kind = match self.def_map.edition {
+            Edition::Edition2015 => PathKind::Plain,
+            _ => PathKind::Abs,
         };
         let path =
             ModPath::from_segments(path_kind, [krate.clone(), name![prelude], edition].into_iter());
@@ -524,7 +534,7 @@ impl DefCollector<'_> {
             match per_ns.types {
                 Some((ModuleDefId::ModuleId(m), _)) => {
                     self.def_map.prelude = Some(m);
-                    return;
+                    break;
                 }
                 types => {
                     tracing::debug!(
@@ -839,7 +849,10 @@ impl DefCollector<'_> {
                 tracing::debug!("resolved import {:?} ({:?}) to {:?}", name, import, def);
 
                 // extern crates in the crate root are special-cased to insert entries into the extern prelude: rust-lang/rust#54658
-                if import.is_extern_crate && module_id == self.def_map.root {
+                if import.is_extern_crate
+                    && self.def_map.block.is_none()
+                    && module_id == self.def_map.root
+                {
                     if let (Some(ModuleDefId::ModuleId(def)), Some(name)) = (def.take_types(), name)
                     {
                         self.def_map.extern_prelude.insert(name.clone(), def);
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/nameres/mod_resolution.rs b/src/tools/rust-analyzer/crates/hir-def/src/nameres/mod_resolution.rs
index 99f7f1b549e2..ca7bcc814e8f 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/nameres/mod_resolution.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/nameres/mod_resolution.rs
@@ -65,6 +65,7 @@ impl ModDir {
         name: &Name,
         attr_path: Option<&SmolStr>,
     ) -> Result<(FileId, bool, ModDir), Box<[String]>> {
+        let name = name.unescaped();
         let orig_file_id = file_id.original_file(db.upcast());
 
         let mut candidate_files = ArrayVec::<_, 2>::new();
@@ -73,12 +74,10 @@ impl ModDir {
                 candidate_files.push(self.dir_path.join_attr(attr_path, self.root_non_dir_owner))
             }
             None if file_id.is_include_macro(db.upcast()) => {
-                let name = name.unescaped();
                 candidate_files.push(format!("{}.rs", name));
                 candidate_files.push(format!("{}/mod.rs", name));
             }
             None => {
-                let name = name.unescaped();
                 candidate_files.push(format!("{}{}.rs", self.dir_path.0, name));
                 candidate_files.push(format!("{}{}/mod.rs", self.dir_path.0, name));
             }
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/nameres/tests/mod_resolution.rs b/src/tools/rust-analyzer/crates/hir-def/src/nameres/tests/mod_resolution.rs
index 3fa585574dee..ba3bf8b5a5cf 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/nameres/tests/mod_resolution.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/nameres/tests/mod_resolution.rs
@@ -127,7 +127,15 @@ mod r#async;
 use self::r#async::Bar;
 
 //- /async.rs
+mod foo;
+mod r#async;
 pub struct Bar;
+
+//- /async/foo.rs
+pub struct Foo;
+
+//- /async/async.rs
+pub struct Baz;
 "#,
         expect![[r#"
             crate
@@ -136,6 +144,14 @@ pub struct Bar;
 
             crate::r#async
             Bar: t v
+            foo: t
+            r#async: t
+
+            crate::r#async::foo
+            Foo: t v
+
+            crate::r#async::r#async
+            Baz: t v
         "#]],
     );
 }
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/resolver.rs b/src/tools/rust-analyzer/crates/hir-def/src/resolver.rs
index 3163fa0f93fa..8aa5973cac57 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/resolver.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/resolver.rs
@@ -31,12 +31,10 @@ pub struct Resolver {
     ///
     /// When using, you generally want to process the scopes in reverse order,
     /// there's `scopes` *method* for that.
-    ///
-    /// Invariant: There exists at least one Scope::ModuleScope at the start of the vec.
     scopes: Vec<Scope>,
+    module_scope: ModuleItemMap,
 }
 
-// FIXME how to store these best
 #[derive(Debug, Clone)]
 struct ModuleItemMap {
     def_map: Arc<DefMap>,
@@ -53,7 +51,7 @@ struct ExprScope {
 #[derive(Debug, Clone)]
 enum Scope {
     /// All the items and imported names of a module
-    ModuleScope(ModuleItemMap),
+    BlockScope(ModuleItemMap),
     /// Brings the generic parameters of an item into scope
     GenericParams { def: GenericDefId, params: Interned<GenericParams> },
     /// Brings `Self` in `impl` block into scope
@@ -127,24 +125,6 @@ impl Resolver {
         }
     }
 
-    fn scopes(&self) -> impl Iterator<Item = &Scope> {
-        self.scopes.iter().rev()
-    }
-
-    fn resolve_module_path(
-        &self,
-        db: &dyn DefDatabase,
-        path: &ModPath,
-        shadow: BuiltinShadowMode,
-    ) -> PerNs {
-        let (item_map, module) = self.module_scope();
-        let (module_res, segment_index) = item_map.resolve_path(db, module, path, shadow);
-        if segment_index.is_some() {
-            return PerNs::none();
-        }
-        module_res
-    }
-
     pub fn resolve_module_path_in_items(&self, db: &dyn DefDatabase, path: &ModPath) -> PerNs {
         self.resolve_module_path(db, path, BuiltinShadowMode::Module)
     }
@@ -155,7 +135,7 @@ impl Resolver {
         db: &dyn DefDatabase,
         path: &ModPath,
     ) -> Option<PerNs> {
-        let (item_map, module) = self.module_scope();
+        let (item_map, module) = self.item_scope();
         let (module_res, idx) = item_map.resolve_path(db, module, path, BuiltinShadowMode::Module);
         match module_res.take_types()? {
             ModuleDefId::TraitId(it) => {
@@ -183,37 +163,38 @@ impl Resolver {
     ) -> Option<(TypeNs, Option<usize>)> {
         let first_name = path.segments().first()?;
         let skip_to_mod = path.kind != PathKind::Plain;
+        if skip_to_mod {
+            return self.module_scope.resolve_path_in_type_ns(db, path);
+        }
+
+        let remaining_idx = || if path.segments().len() == 1 { None } else { Some(1) };
+
         for scope in self.scopes() {
             match scope {
                 Scope::ExprScope(_) => continue,
-                Scope::GenericParams { .. } | Scope::ImplDefScope(_) if skip_to_mod => continue,
-
                 Scope::GenericParams { params, def } => {
                     if let Some(id) = params.find_type_by_name(first_name, *def) {
-                        let idx = if path.segments().len() == 1 { None } else { Some(1) };
-                        return Some((TypeNs::GenericParam(id), idx));
+                        return Some((TypeNs::GenericParam(id), remaining_idx()));
                     }
                 }
-                Scope::ImplDefScope(impl_) => {
+                &Scope::ImplDefScope(impl_) => {
                     if first_name == &name![Self] {
-                        let idx = if path.segments().len() == 1 { None } else { Some(1) };
-                        return Some((TypeNs::SelfType(*impl_), idx));
+                        return Some((TypeNs::SelfType(impl_), remaining_idx()));
                     }
                 }
-                Scope::AdtScope(adt) => {
+                &Scope::AdtScope(adt) => {
                     if first_name == &name![Self] {
-                        let idx = if path.segments().len() == 1 { None } else { Some(1) };
-                        return Some((TypeNs::AdtSelfType(*adt), idx));
+                        return Some((TypeNs::AdtSelfType(adt), remaining_idx()));
                     }
                 }
-                Scope::ModuleScope(m) => {
+                Scope::BlockScope(m) => {
                     if let Some(res) = m.resolve_path_in_type_ns(db, path) {
                         return Some(res);
                     }
                 }
             }
         }
-        None
+        self.module_scope.resolve_path_in_type_ns(db, path)
     }
 
     pub fn resolve_path_in_type_ns_fully(
@@ -235,7 +216,7 @@ impl Resolver {
     ) -> Option<Visibility> {
         match visibility {
             RawVisibility::Module(_) => {
-                let (item_map, module) = self.module_scope();
+                let (item_map, module) = self.item_scope();
                 item_map.resolve_visibility(db, module, visibility)
             }
             RawVisibility::Public => Some(Visibility::Public),
@@ -251,18 +232,14 @@ impl Resolver {
         let tmp = name![self];
         let first_name = if path.is_self() { &tmp } else { path.segments().first()? };
         let skip_to_mod = path.kind != PathKind::Plain && !path.is_self();
+        if skip_to_mod {
+            return self.module_scope.resolve_path_in_value_ns(db, path);
+        }
+
         for scope in self.scopes() {
             match scope {
-                Scope::AdtScope(_)
-                | Scope::ExprScope(_)
-                | Scope::GenericParams { .. }
-                | Scope::ImplDefScope(_)
-                    if skip_to_mod =>
-                {
-                    continue
-                }
-
-                Scope::ExprScope(scope) if n_segments <= 1 => {
+                Scope::ExprScope(_) if n_segments > 1 => continue,
+                Scope::ExprScope(scope) => {
                     let entry = scope
                         .expr_scopes
                         .entries(scope.scope_id)
@@ -273,44 +250,39 @@ impl Resolver {
                         return Some(ResolveValueResult::ValueNs(ValueNs::LocalBinding(e.pat())));
                     }
                 }
-                Scope::ExprScope(_) => continue,
-
                 Scope::GenericParams { params, def } if n_segments > 1 => {
                     if let Some(id) = params.find_type_by_name(first_name, *def) {
                         let ty = TypeNs::GenericParam(id);
                         return Some(ResolveValueResult::Partial(ty, 1));
                     }
                 }
-                Scope::GenericParams { params, def } if n_segments == 1 => {
+                Scope::GenericParams { .. } if n_segments != 1 => continue,
+                Scope::GenericParams { params, def } => {
                     if let Some(id) = params.find_const_by_name(first_name, *def) {
                         let val = ValueNs::GenericParam(id);
                         return Some(ResolveValueResult::ValueNs(val));
                     }
                 }
-                Scope::GenericParams { .. } => continue,
 
-                Scope::ImplDefScope(impl_) => {
+                &Scope::ImplDefScope(impl_) => {
                     if first_name == &name![Self] {
-                        if n_segments > 1 {
-                            let ty = TypeNs::SelfType(*impl_);
-                            return Some(ResolveValueResult::Partial(ty, 1));
+                        return Some(if n_segments > 1 {
+                            ResolveValueResult::Partial(TypeNs::SelfType(impl_), 1)
                         } else {
-                            return Some(ResolveValueResult::ValueNs(ValueNs::ImplSelf(*impl_)));
-                        }
+                            ResolveValueResult::ValueNs(ValueNs::ImplSelf(impl_))
+                        });
                     }
                 }
+                // bare `Self` doesn't work in the value namespace in a struct/enum definition
+                Scope::AdtScope(_) if n_segments == 1 => continue,
                 Scope::AdtScope(adt) => {
-                    if n_segments == 1 {
-                        // bare `Self` doesn't work in the value namespace in a struct/enum definition
-                        continue;
-                    }
                     if first_name == &name![Self] {
                         let ty = TypeNs::AdtSelfType(*adt);
                         return Some(ResolveValueResult::Partial(ty, 1));
                     }
                 }
 
-                Scope::ModuleScope(m) => {
+                Scope::BlockScope(m) => {
                     if let Some(def) = m.resolve_path_in_value_ns(db, path) {
                         return Some(def);
                     }
@@ -318,15 +290,16 @@ impl Resolver {
             }
         }
 
+        if let res @ Some(_) = self.module_scope.resolve_path_in_value_ns(db, path) {
+            return res;
+        }
+
         // If a path of the shape `u16::from_le_bytes` failed to resolve at all, then we fall back
         // to resolving to the primitive type, to allow this to still work in the presence of
         // `use core::u16;`.
         if path.kind == PathKind::Plain && path.segments().len() > 1 {
-            match BuiltinType::by_name(&path.segments()[0]) {
-                Some(builtin) => {
-                    return Some(ResolveValueResult::Partial(TypeNs::BuiltinType(builtin), 1));
-                }
-                None => {}
+            if let Some(builtin) = BuiltinType::by_name(&path.segments()[0]) {
+                return Some(ResolveValueResult::Partial(TypeNs::BuiltinType(builtin), 1));
             }
         }
 
@@ -345,7 +318,7 @@ impl Resolver {
     }
 
     pub fn resolve_path_as_macro(&self, db: &dyn DefDatabase, path: &ModPath) -> Option<MacroId> {
-        let (item_map, module) = self.module_scope();
+        let (item_map, module) = self.item_scope();
         item_map.resolve_path(db, module, path, BuiltinShadowMode::Other).0.take_macros()
     }
 
@@ -395,30 +368,43 @@ impl Resolver {
         for scope in self.scopes() {
             scope.process_names(&mut res, db);
         }
+        let ModuleItemMap { ref def_map, module_id } = self.module_scope;
+        // FIXME: should we provide `self` here?
+        // f(
+        //     Name::self_param(),
+        //     PerNs::types(Resolution::Def {
+        //         def: m.module.into(),
+        //     }),
+        // );
+        def_map[module_id].scope.entries().for_each(|(name, def)| {
+            res.add_per_ns(name, def);
+        });
+        def_map[module_id].scope.legacy_macros().for_each(|(name, macs)| {
+            macs.iter().for_each(|&mac| {
+                res.add(name, ScopeDef::ModuleDef(ModuleDefId::MacroId(MacroId::from(mac))));
+            })
+        });
+        def_map.extern_prelude().for_each(|(name, &def)| {
+            res.add(name, ScopeDef::ModuleDef(ModuleDefId::ModuleId(def)));
+        });
+        BUILTIN_SCOPE.iter().for_each(|(name, &def)| {
+            res.add_per_ns(name, def);
+        });
+        if let Some(prelude) = def_map.prelude() {
+            let prelude_def_map = prelude.def_map(db);
+            for (name, def) in prelude_def_map[prelude.local_id].scope.entries() {
+                res.add_per_ns(name, def)
+            }
+        }
         res.map
     }
 
     pub fn traits_in_scope(&self, db: &dyn DefDatabase) -> FxHashSet<TraitId> {
         let mut traits = FxHashSet::default();
+
         for scope in self.scopes() {
             match scope {
-                Scope::ModuleScope(m) => {
-                    if let Some(prelude) = m.def_map.prelude() {
-                        let prelude_def_map = prelude.def_map(db);
-                        traits.extend(prelude_def_map[prelude.local_id].scope.traits());
-                    }
-                    traits.extend(m.def_map[m.module_id].scope.traits());
-
-                    // Add all traits that are in scope because of the containing DefMaps
-                    m.def_map.with_ancestor_maps(db, m.module_id, &mut |def_map, module| {
-                        if let Some(prelude) = def_map.prelude() {
-                            let prelude_def_map = prelude.def_map(db);
-                            traits.extend(prelude_def_map[prelude.local_id].scope.traits());
-                        }
-                        traits.extend(def_map[module].scope.traits());
-                        None::<()>
-                    });
-                }
+                Scope::BlockScope(m) => traits.extend(m.def_map[m.module_id].scope.traits()),
                 &Scope::ImplDefScope(impl_) => {
                     if let Some(target_trait) = &db.impl_data(impl_).target_trait {
                         if let Some(TypeNs::TraitId(trait_)) =
@@ -431,35 +417,28 @@ impl Resolver {
                 _ => (),
             }
         }
+
+        // Fill in the prelude traits
+        if let Some(prelude) = self.module_scope.def_map.prelude() {
+            let prelude_def_map = prelude.def_map(db);
+            traits.extend(prelude_def_map[prelude.local_id].scope.traits());
+        }
+        // Fill in module visible traits
+        traits.extend(self.module_scope.def_map[self.module_scope.module_id].scope.traits());
         traits
     }
 
-    fn module_scope(&self) -> (&DefMap, LocalModuleId) {
-        self.scopes()
-            .find_map(|scope| match scope {
-                Scope::ModuleScope(m) => Some((&*m.def_map, m.module_id)),
-                _ => None,
-            })
-            .expect("module scope invariant violated")
-    }
-
     pub fn module(&self) -> ModuleId {
-        let (def_map, local_id) = self.module_scope();
+        let (def_map, local_id) = self.item_scope();
         def_map.module_id(local_id)
     }
 
     pub fn krate(&self) -> CrateId {
-        self.def_map().krate()
+        self.module_scope.def_map.krate()
     }
 
     pub fn def_map(&self) -> &DefMap {
-        self.scopes
-            .get(0)
-            .and_then(|scope| match scope {
-                Scope::ModuleScope(m) => Some(&m.def_map),
-                _ => None,
-            })
-            .expect("module scope invariant violated")
+        self.item_scope().0
     }
 
     pub fn where_predicates_in_scope(
@@ -488,6 +467,36 @@ impl Resolver {
     }
 }
 
+impl Resolver {
+    fn scopes(&self) -> impl Iterator<Item = &Scope> {
+        self.scopes.iter().rev()
+    }
+
+    fn resolve_module_path(
+        &self,
+        db: &dyn DefDatabase,
+        path: &ModPath,
+        shadow: BuiltinShadowMode,
+    ) -> PerNs {
+        let (item_map, module) = self.item_scope();
+        let (module_res, segment_index) = item_map.resolve_path(db, module, path, shadow);
+        if segment_index.is_some() {
+            return PerNs::none();
+        }
+        module_res
+    }
+
+    /// The innermost block scope that contains items or the module scope that contains this resolver.
+    fn item_scope(&self) -> (&DefMap, LocalModuleId) {
+        self.scopes()
+            .find_map(|scope| match scope {
+                Scope::BlockScope(m) => Some((&*m.def_map, m.module_id)),
+                _ => None,
+            })
+            .unwrap_or((&self.module_scope.def_map, self.module_scope.module_id))
+    }
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum ScopeDef {
     ModuleDef(ModuleDefId),
@@ -502,14 +511,7 @@ pub enum ScopeDef {
 impl Scope {
     fn process_names(&self, acc: &mut ScopeNames, db: &dyn DefDatabase) {
         match self {
-            Scope::ModuleScope(m) => {
-                // FIXME: should we provide `self` here?
-                // f(
-                //     Name::self_param(),
-                //     PerNs::types(Resolution::Def {
-                //         def: m.module.into(),
-                //     }),
-                // );
+            Scope::BlockScope(m) => {
                 m.def_map[m.module_id].scope.entries().for_each(|(name, def)| {
                     acc.add_per_ns(name, def);
                 });
@@ -521,18 +523,6 @@ impl Scope {
                         );
                     })
                 });
-                m.def_map.extern_prelude().for_each(|(name, &def)| {
-                    acc.add(name, ScopeDef::ModuleDef(ModuleDefId::ModuleId(def)));
-                });
-                BUILTIN_SCOPE.iter().for_each(|(name, &def)| {
-                    acc.add_per_ns(name, def);
-                });
-                if let Some(prelude) = m.def_map.prelude() {
-                    let prelude_def_map = prelude.def_map(db);
-                    for (name, def) in prelude_def_map[prelude.local_id].scope.entries() {
-                        acc.add_per_ns(name, def)
-                    }
-                }
             }
             Scope::GenericParams { params, def: parent } => {
                 let parent = *parent;
@@ -596,7 +586,7 @@ pub fn resolver_for_scope(
         if let Some(block) = scopes.block(scope) {
             if let Some(def_map) = db.block_def_map(block) {
                 let root = def_map.root();
-                r = r.push_module_scope(def_map, root);
+                r = r.push_block_scope(def_map, root);
                 // FIXME: This adds as many module scopes as there are blocks, but resolving in each
                 // already traverses all parents, so this is O(n²). I think we could only store the
                 // innermost module scope instead?
@@ -623,8 +613,8 @@ impl Resolver {
         self.push_scope(Scope::ImplDefScope(impl_def))
     }
 
-    fn push_module_scope(self, def_map: Arc<DefMap>, module_id: LocalModuleId) -> Resolver {
-        self.push_scope(Scope::ModuleScope(ModuleItemMap { def_map, module_id }))
+    fn push_block_scope(self, def_map: Arc<DefMap>, module_id: LocalModuleId) -> Resolver {
+        self.push_scope(Scope::BlockScope(ModuleItemMap { def_map, module_id }))
     }
 
     fn push_expr_scope(
@@ -768,14 +758,19 @@ pub trait HasResolver: Copy {
 impl HasResolver for ModuleId {
     fn resolver(self, db: &dyn DefDatabase) -> Resolver {
         let mut def_map = self.def_map(db);
-        let mut modules: SmallVec<[_; 2]> = smallvec![(def_map.clone(), self.local_id)];
+        let mut modules: SmallVec<[_; 1]> = smallvec![];
+        let mut module_id = self.local_id;
         while let Some(parent) = def_map.parent() {
+            modules.push((def_map, module_id));
             def_map = parent.def_map(db);
-            modules.push((def_map.clone(), parent.local_id));
+            module_id = parent.local_id;
         }
-        let mut resolver = Resolver { scopes: Vec::with_capacity(modules.len()) };
+        let mut resolver = Resolver {
+            scopes: Vec::with_capacity(modules.len()),
+            module_scope: ModuleItemMap { def_map, module_id },
+        };
         for (def_map, module) in modules.into_iter().rev() {
-            resolver = resolver.push_module_scope(def_map, module);
+            resolver = resolver.push_block_scope(def_map, module);
         }
         resolver
     }
diff --git a/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs b/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs
index d753d88470c4..fc128102f225 100644
--- a/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs
@@ -969,7 +969,7 @@ impl ExpandTo {
         if parent.kind() == MACRO_EXPR
             && parent
                 .parent()
-                .map_or(true, |p| matches!(p.kind(), EXPR_STMT | STMT_LIST | MACRO_STMTS))
+                .map_or(false, |p| matches!(p.kind(), EXPR_STMT | STMT_LIST | MACRO_STMTS))
         {
             return ExpandTo::Statements;
         }
diff --git a/src/tools/rust-analyzer/crates/hir-expand/src/name.rs b/src/tools/rust-analyzer/crates/hir-expand/src/name.rs
index 2b859f775095..4ce21a57967c 100644
--- a/src/tools/rust-analyzer/crates/hir-expand/src/name.rs
+++ b/src/tools/rust-analyzer/crates/hir-expand/src/name.rs
@@ -336,6 +336,7 @@ pub mod known {
         test,
         test_case,
         recursion_limit,
+        feature,
         // Safe intrinsics
         abort,
         add_with_overflow,
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/autoderef.rs b/src/tools/rust-analyzer/crates/hir-ty/src/autoderef.rs
index b6f226dbfd20..344036dd8139 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/autoderef.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/autoderef.rs
@@ -104,8 +104,7 @@ pub(crate) fn deref(table: &mut InferenceTable<'_>, ty: Ty) -> Option<Ty> {
 
 fn builtin_deref(ty: &Ty) -> Option<&Ty> {
     match ty.kind(Interner) {
-        TyKind::Ref(.., ty) => Some(ty),
-        TyKind::Raw(.., ty) => Some(ty),
+        TyKind::Ref(.., ty) | TyKind::Raw(.., ty) => Some(ty),
         _ => None,
     }
 }
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/chalk_ext.rs b/src/tools/rust-analyzer/crates/hir-ty/src/chalk_ext.rs
index a9c124b42dc2..4a5533c6487e 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/chalk_ext.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/chalk_ext.rs
@@ -164,6 +164,8 @@ impl TyExt for Ty {
 
     fn dyn_trait(&self) -> Option<TraitId> {
         let trait_ref = match self.kind(Interner) {
+            // The principal trait bound should be the first element of the bounds. This is an
+            // invariant ensured by `TyLoweringContext::lower_dyn_trait()`.
             TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().get(0).and_then(|b| {
                 match b.skip_binders() {
                     WhereClause::Implemented(trait_ref) => Some(trait_ref),
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/db.rs b/src/tools/rust-analyzer/crates/hir-ty/src/db.rs
index b385b1cafaef..69283e55a4c2 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/db.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/db.rs
@@ -150,6 +150,14 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
         id: chalk_db::AssociatedTyValueId,
     ) -> Arc<chalk_db::AssociatedTyValue>;
 
+    #[salsa::invoke(crate::traits::normalize_projection_query)]
+    #[salsa::transparent]
+    fn normalize_projection(
+        &self,
+        projection: crate::ProjectionTy,
+        env: Arc<crate::TraitEnvironment>,
+    ) -> Ty;
+
     #[salsa::invoke(trait_solve_wait)]
     #[salsa::transparent]
     fn trait_solve(
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/expr.rs b/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/expr.rs
index 642e03edd230..c8df4c796efc 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/expr.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/expr.rs
@@ -159,12 +159,7 @@ impl ExprValidator {
         }
 
         let pattern_arena = Arena::new();
-        let cx = MatchCheckCtx {
-            module: self.owner.module(db.upcast()),
-            body: self.owner,
-            db,
-            pattern_arena: &pattern_arena,
-        };
+        let cx = MatchCheckCtx::new(self.owner.module(db.upcast()), self.owner, db, &pattern_arena);
 
         let mut m_arms = Vec::with_capacity(arms.len());
         let mut has_lowering_errors = false;
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/deconstruct_pat.rs b/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/deconstruct_pat.rs
index bbbe539c13fb..47d60fc41e70 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/deconstruct_pat.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/deconstruct_pat.rs
@@ -52,7 +52,10 @@ use hir_def::{EnumVariantId, HasModule, LocalFieldId, VariantId};
 use smallvec::{smallvec, SmallVec};
 use stdx::never;
 
-use crate::{infer::normalize, AdtId, Interner, Scalar, Ty, TyExt, TyKind};
+use crate::{
+    infer::normalize, inhabitedness::is_enum_variant_uninhabited_from, AdtId, Interner, Scalar, Ty,
+    TyExt, TyKind,
+};
 
 use super::{
     is_box,
@@ -557,8 +560,8 @@ impl SplitWildcard {
             TyKind::Scalar(Scalar::Bool) => smallvec![make_range(0, 1, Scalar::Bool)],
             // TyKind::Array(..) if ... => unhandled(),
             TyKind::Array(..) | TyKind::Slice(..) => unhandled(),
-            &TyKind::Adt(AdtId(hir_def::AdtId::EnumId(enum_id)), ..) => {
-                let enum_data = cx.db.enum_data(enum_id);
+            TyKind::Adt(AdtId(hir_def::AdtId::EnumId(enum_id)), subst) => {
+                let enum_data = cx.db.enum_data(*enum_id);
 
                 // If the enum is declared as `#[non_exhaustive]`, we treat it as if it had an
                 // additional "unknown" constructor.
@@ -591,14 +594,15 @@ impl SplitWildcard {
                 let mut ctors: SmallVec<[_; 1]> = enum_data
                     .variants
                     .iter()
-                    .filter(|&(_, _v)| {
+                    .map(|(local_id, _)| EnumVariantId { parent: *enum_id, local_id })
+                    .filter(|&variant| {
                         // If `exhaustive_patterns` is enabled, we exclude variants known to be
                         // uninhabited.
                         let is_uninhabited = is_exhaustive_pat_feature
-                            && unimplemented!("after MatchCheckCtx.feature_exhaustive_patterns()");
+                            && is_enum_variant_uninhabited_from(variant, subst, cx.module, cx.db);
                         !is_uninhabited
                     })
-                    .map(|(local_id, _)| Variant(EnumVariantId { parent: enum_id, local_id }))
+                    .map(Variant)
                     .collect();
 
                 if is_secretly_empty || is_declared_nonexhaustive {
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/usefulness.rs b/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/usefulness.rs
index 1221327b9510..c4d709a975b0 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/usefulness.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/diagnostics/match_check/usefulness.rs
@@ -277,7 +277,7 @@ use hir_def::{AdtId, DefWithBodyId, HasModule, ModuleId};
 use smallvec::{smallvec, SmallVec};
 use typed_arena::Arena;
 
-use crate::{db::HirDatabase, Ty, TyExt};
+use crate::{db::HirDatabase, inhabitedness::is_ty_uninhabited_from, Ty, TyExt};
 
 use super::deconstruct_pat::{Constructor, DeconstructedPat, Fields, SplitWildcard};
 
@@ -289,13 +289,27 @@ pub(crate) struct MatchCheckCtx<'a, 'p> {
     pub(crate) db: &'a dyn HirDatabase,
     /// Lowered patterns from arms plus generated by the check.
     pub(crate) pattern_arena: &'p Arena<DeconstructedPat<'p>>,
+    exhaustive_patterns: bool,
 }
 
 impl<'a, 'p> MatchCheckCtx<'a, 'p> {
-    pub(super) fn is_uninhabited(&self, _ty: &Ty) -> bool {
-        // FIXME(iDawer) implement exhaustive_patterns feature. More info in:
-        // Tracking issue for RFC 1872: exhaustive_patterns feature https://github.com/rust-lang/rust/issues/51085
-        false
+    pub(crate) fn new(
+        module: ModuleId,
+        body: DefWithBodyId,
+        db: &'a dyn HirDatabase,
+        pattern_arena: &'p Arena<DeconstructedPat<'p>>,
+    ) -> Self {
+        let def_map = db.crate_def_map(module.krate());
+        let exhaustive_patterns = def_map.is_unstable_feature_enabled("exhaustive_patterns");
+        Self { module, body, db, pattern_arena, exhaustive_patterns }
+    }
+
+    pub(super) fn is_uninhabited(&self, ty: &Ty) -> bool {
+        if self.feature_exhaustive_patterns() {
+            is_ty_uninhabited_from(ty, self.module, self.db)
+        } else {
+            false
+        }
     }
 
     /// Returns whether the given type is an enum from another crate declared `#[non_exhaustive]`.
@@ -311,10 +325,9 @@ impl<'a, 'p> MatchCheckCtx<'a, 'p> {
         }
     }
 
-    // Rust feature described as "Allows exhaustive pattern matching on types that contain uninhabited types."
+    // Rust's unstable feature described as "Allows exhaustive pattern matching on types that contain uninhabited types."
     pub(super) fn feature_exhaustive_patterns(&self) -> bool {
-        // FIXME see MatchCheckCtx::is_uninhabited
-        false
+        self.exhaustive_patterns
     }
 }
 
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/display.rs b/src/tools/rust-analyzer/crates/hir-ty/src/display.rs
index d2f9c2b8b1e1..874abdaea837 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/display.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/display.rs
@@ -533,6 +533,7 @@ impl HirDisplay for Ty {
                             f.db.upcast(),
                             ItemInNs::Types((*def_id).into()),
                             module_id,
+                            false,
                         ) {
                             write!(f, "{}", path)?;
                         } else {
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs b/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs
index 5df48e5fdcba..e37763e8ea7f 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/infer.rs
@@ -182,7 +182,7 @@ pub(crate) type InferResult<T> = Result<InferOk<T>, TypeError>;
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum InferenceDiagnostic {
     NoSuchField { expr: ExprId },
-    BreakOutsideOfLoop { expr: ExprId },
+    BreakOutsideOfLoop { expr: ExprId, is_break: bool },
     MismatchedArgCount { call_expr: ExprId, expected: usize, found: usize },
 }
 
@@ -418,18 +418,45 @@ pub(crate) struct InferenceContext<'a> {
 
 #[derive(Clone, Debug)]
 struct BreakableContext {
+    /// Whether this context contains at least one break expression.
     may_break: bool,
+    /// The coercion target of the context.
     coerce: CoerceMany,
+    /// The optional label of the context.
     label: Option<name::Name>,
+    kind: BreakableKind,
+}
+
+#[derive(Clone, Debug)]
+enum BreakableKind {
+    Block,
+    Loop,
+    /// A border is something like an async block, closure etc. Anything that prevents
+    /// breaking/continuing through
+    Border,
 }
 
 fn find_breakable<'c>(
     ctxs: &'c mut [BreakableContext],
     label: Option<&name::Name>,
 ) -> Option<&'c mut BreakableContext> {
+    let mut ctxs = ctxs
+        .iter_mut()
+        .rev()
+        .take_while(|it| matches!(it.kind, BreakableKind::Block | BreakableKind::Loop));
     match label {
-        Some(_) => ctxs.iter_mut().rev().find(|ctx| ctx.label.as_ref() == label),
-        None => ctxs.last_mut(),
+        Some(_) => ctxs.find(|ctx| ctx.label.as_ref() == label),
+        None => ctxs.find(|ctx| matches!(ctx.kind, BreakableKind::Loop)),
+    }
+}
+
+fn find_continuable<'c>(
+    ctxs: &'c mut [BreakableContext],
+    label: Option<&name::Name>,
+) -> Option<&'c mut BreakableContext> {
+    match label {
+        Some(_) => find_breakable(ctxs, label).filter(|it| matches!(it.kind, BreakableKind::Loop)),
+        None => find_breakable(ctxs, label),
     }
 }
 
@@ -646,10 +673,6 @@ impl<'a> InferenceContext<'a> {
         )
     }
 
-    fn resolve_obligations_as_possible(&mut self) {
-        self.table.resolve_obligations_as_possible();
-    }
-
     fn push_obligation(&mut self, o: DomainGoal) {
         self.table.register_obligation(o.cast(Interner));
     }
@@ -669,7 +692,6 @@ impl<'a> InferenceContext<'a> {
     }
 
     fn resolve_ty_shallow(&mut self, ty: &Ty) -> Ty {
-        self.resolve_obligations_as_possible();
         self.table.resolve_ty_shallow(ty)
     }
 
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/infer/expr.rs b/src/tools/rust-analyzer/crates/hir-ty/src/infer/expr.rs
index 2a13106390d9..2d04a864a2cf 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/infer/expr.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/infer/expr.rs
@@ -10,7 +10,7 @@ use chalk_ir::{
     cast::Cast, fold::Shift, DebruijnIndex, GenericArgData, Mutability, TyVariableKind,
 };
 use hir_def::{
-    expr::{ArithOp, Array, BinaryOp, CmpOp, Expr, ExprId, Literal, Statement, UnaryOp},
+    expr::{ArithOp, Array, BinaryOp, CmpOp, Expr, ExprId, LabelId, Literal, Statement, UnaryOp},
     generics::TypeOrConstParamData,
     path::{GenericArg, GenericArgs},
     resolver::resolver_for_expr,
@@ -23,7 +23,7 @@ use syntax::ast::RangeOp;
 use crate::{
     autoderef::{self, Autoderef},
     consteval,
-    infer::coerce::CoerceMany,
+    infer::{coerce::CoerceMany, find_continuable, BreakableKind},
     lower::{
         const_or_path_to_chalk, generic_arg_to_chalk, lower_to_chalk_mutability, ParamLoweringMode,
     },
@@ -120,32 +120,37 @@ impl<'a> InferenceContext<'a> {
                 let ty = match label {
                     Some(_) => {
                         let break_ty = self.table.new_type_var();
-                        self.breakables.push(BreakableContext {
-                            may_break: false,
-                            coerce: CoerceMany::new(break_ty.clone()),
-                            label: label.map(|label| self.body[label].name.clone()),
-                        });
-                        let ty = self.infer_block(
-                            tgt_expr,
-                            statements,
-                            *tail,
-                            &Expectation::has_type(break_ty),
+                        let (breaks, ty) = self.with_breakable_ctx(
+                            BreakableKind::Block,
+                            break_ty.clone(),
+                            *label,
+                            |this| {
+                                this.infer_block(
+                                    tgt_expr,
+                                    statements,
+                                    *tail,
+                                    &Expectation::has_type(break_ty),
+                                )
+                            },
                         );
-                        let ctxt = self.breakables.pop().expect("breakable stack broken");
-                        if ctxt.may_break {
-                            ctxt.coerce.complete()
-                        } else {
-                            ty
-                        }
+                        breaks.unwrap_or(ty)
                     }
                     None => self.infer_block(tgt_expr, statements, *tail, expected),
                 };
                 self.resolver = old_resolver;
                 ty
             }
-            Expr::Unsafe { body } | Expr::Const { body } => self.infer_expr(*body, expected),
+            Expr::Unsafe { body } => self.infer_expr(*body, expected),
+            Expr::Const { body } => {
+                self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
+                    this.infer_expr(*body, expected)
+                })
+                .1
+            }
             Expr::TryBlock { body } => {
-                let _inner = self.infer_expr(*body, expected);
+                self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
+                    let _inner = this.infer_expr(*body, expected);
+                });
                 // FIXME should be std::result::Result<{inner}, _>
                 self.err_ty()
             }
@@ -154,7 +159,10 @@ impl<'a> InferenceContext<'a> {
                 let prev_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
                 let prev_ret_ty = mem::replace(&mut self.return_ty, ret_ty.clone());
 
-                let inner_ty = self.infer_expr_coerce(*body, &Expectation::has_type(ret_ty));
+                let (_, inner_ty) =
+                    self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
+                        this.infer_expr_coerce(*body, &Expectation::has_type(ret_ty))
+                    });
 
                 self.diverges = prev_diverges;
                 self.return_ty = prev_ret_ty;
@@ -166,54 +174,44 @@ impl<'a> InferenceContext<'a> {
                 TyKind::OpaqueType(opaque_ty_id, Substitution::from1(Interner, inner_ty))
                     .intern(Interner)
             }
-            Expr::Loop { body, label } => {
-                self.breakables.push(BreakableContext {
-                    may_break: false,
-                    coerce: CoerceMany::new(self.table.new_type_var()),
-                    label: label.map(|label| self.body[label].name.clone()),
-                });
-                self.infer_expr(*body, &Expectation::has_type(TyBuilder::unit()));
+            &Expr::Loop { body, label } => {
+                let ty = self.table.new_type_var();
+                let (breaks, ()) =
+                    self.with_breakable_ctx(BreakableKind::Loop, ty, label, |this| {
+                        this.infer_expr(body, &Expectation::has_type(TyBuilder::unit()));
+                    });
 
-                let ctxt = self.breakables.pop().expect("breakable stack broken");
-
-                if ctxt.may_break {
-                    self.diverges = Diverges::Maybe;
-                    ctxt.coerce.complete()
-                } else {
-                    TyKind::Never.intern(Interner)
+                match breaks {
+                    Some(breaks) => {
+                        self.diverges = Diverges::Maybe;
+                        breaks
+                    }
+                    None => TyKind::Never.intern(Interner),
                 }
             }
-            Expr::While { condition, body, label } => {
-                self.breakables.push(BreakableContext {
-                    may_break: false,
-                    coerce: CoerceMany::new(self.err_ty()),
-                    label: label.map(|label| self.body[label].name.clone()),
+            &Expr::While { condition, body, label } => {
+                self.with_breakable_ctx(BreakableKind::Loop, self.err_ty(), label, |this| {
+                    this.infer_expr(
+                        condition,
+                        &Expectation::has_type(TyKind::Scalar(Scalar::Bool).intern(Interner)),
+                    );
+                    this.infer_expr(body, &Expectation::has_type(TyBuilder::unit()));
                 });
-                self.infer_expr(
-                    *condition,
-                    &Expectation::has_type(TyKind::Scalar(Scalar::Bool).intern(Interner)),
-                );
-                self.infer_expr(*body, &Expectation::has_type(TyBuilder::unit()));
-                let _ctxt = self.breakables.pop().expect("breakable stack broken");
+
                 // the body may not run, so it diverging doesn't mean we diverge
                 self.diverges = Diverges::Maybe;
                 TyBuilder::unit()
             }
-            Expr::For { iterable, body, pat, label } => {
-                let iterable_ty = self.infer_expr(*iterable, &Expectation::none());
-
-                self.breakables.push(BreakableContext {
-                    may_break: false,
-                    coerce: CoerceMany::new(self.err_ty()),
-                    label: label.map(|label| self.body[label].name.clone()),
-                });
+            &Expr::For { iterable, body, pat, label } => {
+                let iterable_ty = self.infer_expr(iterable, &Expectation::none());
                 let pat_ty =
                     self.resolve_associated_type(iterable_ty, self.resolve_into_iter_item());
 
-                self.infer_pat(*pat, &pat_ty, BindingMode::default());
+                self.infer_pat(pat, &pat_ty, BindingMode::default());
+                self.with_breakable_ctx(BreakableKind::Loop, self.err_ty(), label, |this| {
+                    this.infer_expr(body, &Expectation::has_type(TyBuilder::unit()));
+                });
 
-                self.infer_expr(*body, &Expectation::has_type(TyBuilder::unit()));
-                let _ctxt = self.breakables.pop().expect("breakable stack broken");
                 // the body may not run, so it diverging doesn't mean we diverge
                 self.diverges = Diverges::Maybe;
                 TyBuilder::unit()
@@ -269,7 +267,9 @@ impl<'a> InferenceContext<'a> {
                 let prev_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
                 let prev_ret_ty = mem::replace(&mut self.return_ty, ret_ty.clone());
 
-                self.infer_expr_coerce(*body, &Expectation::has_type(ret_ty));
+                self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
+                    this.infer_expr_coerce(*body, &Expectation::has_type(ret_ty));
+                });
 
                 self.diverges = prev_diverges;
                 self.return_ty = prev_ret_ty;
@@ -372,37 +372,45 @@ impl<'a> InferenceContext<'a> {
                 let resolver = resolver_for_expr(self.db.upcast(), self.owner, tgt_expr);
                 self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or_else(|| self.err_ty())
             }
-            Expr::Continue { .. } => TyKind::Never.intern(Interner),
-            Expr::Break { expr, label } => {
-                let mut coerce = match find_breakable(&mut self.breakables, label.as_ref()) {
-                    Some(ctxt) => {
-                        // avoiding the borrowck
-                        mem::replace(
-                            &mut ctxt.coerce,
-                            CoerceMany::new(self.result.standard_types.unknown.clone()),
-                        )
-                    }
-                    None => CoerceMany::new(self.result.standard_types.unknown.clone()),
+            Expr::Continue { label } => {
+                if let None = find_continuable(&mut self.breakables, label.as_ref()) {
+                    self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
+                        expr: tgt_expr,
+                        is_break: false,
+                    });
                 };
-
+                TyKind::Never.intern(Interner)
+            }
+            Expr::Break { expr, label } => {
                 let val_ty = if let Some(expr) = *expr {
                     self.infer_expr(expr, &Expectation::none())
                 } else {
                     TyBuilder::unit()
                 };
 
-                // FIXME: create a synthetic `()` during lowering so we have something to refer to here?
-                coerce.coerce(self, *expr, &val_ty);
+                match find_breakable(&mut self.breakables, label.as_ref()) {
+                    Some(ctxt) => {
+                        // avoiding the borrowck
+                        let mut coerce = mem::replace(
+                            &mut ctxt.coerce,
+                            CoerceMany::new(self.result.standard_types.unknown.clone()),
+                        );
 
-                if let Some(ctxt) = find_breakable(&mut self.breakables, label.as_ref()) {
-                    ctxt.coerce = coerce;
-                    ctxt.may_break = true;
-                } else {
-                    self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
-                        expr: tgt_expr,
-                    });
-                };
+                        // FIXME: create a synthetic `()` during lowering so we have something to refer to here?
+                        coerce.coerce(self, *expr, &val_ty);
 
+                        let ctxt = find_breakable(&mut self.breakables, label.as_ref())
+                            .expect("breakable stack changed during coercion");
+                        ctxt.coerce = coerce;
+                        ctxt.may_break = true;
+                    }
+                    None => {
+                        self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
+                            expr: tgt_expr,
+                            is_break: true,
+                        });
+                    }
+                }
                 TyKind::Never.intern(Interner)
             }
             Expr::Return { expr } => {
@@ -794,9 +802,6 @@ impl<'a> InferenceContext<'a> {
                     None => self.table.new_float_var(),
                 },
             },
-            Expr::MacroStmts { tail, statements } => {
-                self.infer_block(tgt_expr, statements, *tail, expected)
-            }
             Expr::Underscore => {
                 // Underscore expressions may only appear in assignee expressions,
                 // which are handled by `infer_assignee_expr()`, so any underscore
@@ -1475,4 +1480,20 @@ impl<'a> InferenceContext<'a> {
             },
         })
     }
+
+    fn with_breakable_ctx<T>(
+        &mut self,
+        kind: BreakableKind,
+        ty: Ty,
+        label: Option<LabelId>,
+        cb: impl FnOnce(&mut Self) -> T,
+    ) -> (Option<Ty>, T) {
+        self.breakables.push({
+            let label = label.map(|label| self.body[label].name.clone());
+            BreakableContext { kind, may_break: false, coerce: CoerceMany::new(ty), label }
+        });
+        let res = cb(self);
+        let ctx = self.breakables.pop().expect("breakable stack broken");
+        (ctx.may_break.then(|| ctx.coerce.complete()), res)
+    }
 }
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/inhabitedness.rs b/src/tools/rust-analyzer/crates/hir-ty/src/inhabitedness.rs
new file mode 100644
index 000000000000..0c547192ac0d
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/inhabitedness.rs
@@ -0,0 +1,173 @@
+//! Type inhabitedness logic.
+use std::ops::ControlFlow::{self, Break, Continue};
+
+use chalk_ir::{
+    visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor},
+    DebruijnIndex,
+};
+use hir_def::{
+    adt::VariantData, attr::Attrs, type_ref::ConstScalar, visibility::Visibility, AdtId,
+    EnumVariantId, HasModule, Lookup, ModuleId, VariantId,
+};
+
+use crate::{
+    db::HirDatabase, Binders, ConcreteConst, Const, ConstValue, Interner, Substitution, Ty, TyKind,
+};
+
+/// Checks whether a type is visibly uninhabited from a particular module.
+pub(crate) fn is_ty_uninhabited_from(ty: &Ty, target_mod: ModuleId, db: &dyn HirDatabase) -> bool {
+    let mut uninhabited_from = UninhabitedFrom { target_mod, db };
+    let inhabitedness = ty.visit_with(&mut uninhabited_from, DebruijnIndex::INNERMOST);
+    inhabitedness == BREAK_VISIBLY_UNINHABITED
+}
+
+/// Checks whether a variant is visibly uninhabited from a particular module.
+pub(crate) fn is_enum_variant_uninhabited_from(
+    variant: EnumVariantId,
+    subst: &Substitution,
+    target_mod: ModuleId,
+    db: &dyn HirDatabase,
+) -> bool {
+    let enum_data = db.enum_data(variant.parent);
+    let vars_attrs = db.variants_attrs(variant.parent);
+    let is_local = variant.parent.lookup(db.upcast()).container.krate() == target_mod.krate();
+
+    let mut uninhabited_from = UninhabitedFrom { target_mod, db };
+    let inhabitedness = uninhabited_from.visit_variant(
+        variant.into(),
+        &enum_data.variants[variant.local_id].variant_data,
+        subst,
+        &vars_attrs[variant.local_id],
+        is_local,
+    );
+    inhabitedness == BREAK_VISIBLY_UNINHABITED
+}
+
+struct UninhabitedFrom<'a> {
+    target_mod: ModuleId,
+    db: &'a dyn HirDatabase,
+}
+
+const CONTINUE_OPAQUELY_INHABITED: ControlFlow<VisiblyUninhabited> = Continue(());
+const BREAK_VISIBLY_UNINHABITED: ControlFlow<VisiblyUninhabited> = Break(VisiblyUninhabited);
+#[derive(PartialEq, Eq)]
+struct VisiblyUninhabited;
+
+impl TypeVisitor<Interner> for UninhabitedFrom<'_> {
+    type BreakTy = VisiblyUninhabited;
+
+    fn as_dyn(&mut self) -> &mut dyn TypeVisitor<Interner, BreakTy = VisiblyUninhabited> {
+        self
+    }
+
+    fn visit_ty(
+        &mut self,
+        ty: &Ty,
+        outer_binder: DebruijnIndex,
+    ) -> ControlFlow<VisiblyUninhabited> {
+        match ty.kind(Interner) {
+            TyKind::Adt(adt, subst) => self.visit_adt(adt.0, subst),
+            TyKind::Never => BREAK_VISIBLY_UNINHABITED,
+            TyKind::Tuple(..) => ty.super_visit_with(self, outer_binder),
+            TyKind::Array(item_ty, len) => match try_usize_const(len) {
+                Some(0) | None => CONTINUE_OPAQUELY_INHABITED,
+                Some(1..) => item_ty.super_visit_with(self, outer_binder),
+            },
+
+            TyKind::Ref(..) | _ => CONTINUE_OPAQUELY_INHABITED,
+        }
+    }
+
+    fn interner(&self) -> Interner {
+        Interner
+    }
+}
+
+impl UninhabitedFrom<'_> {
+    fn visit_adt(&mut self, adt: AdtId, subst: &Substitution) -> ControlFlow<VisiblyUninhabited> {
+        let attrs = self.db.attrs(adt.into());
+        let adt_non_exhaustive = attrs.by_key("non_exhaustive").exists();
+        let is_local = adt.module(self.db.upcast()).krate() == self.target_mod.krate();
+        if adt_non_exhaustive && !is_local {
+            return CONTINUE_OPAQUELY_INHABITED;
+        }
+
+        // An ADT is uninhabited iff all its variants uninhabited.
+        match adt {
+            // rustc: For now, `union`s are never considered uninhabited.
+            AdtId::UnionId(_) => CONTINUE_OPAQUELY_INHABITED,
+            AdtId::StructId(s) => {
+                let struct_data = self.db.struct_data(s);
+                self.visit_variant(s.into(), &struct_data.variant_data, subst, &attrs, is_local)
+            }
+            AdtId::EnumId(e) => {
+                let vars_attrs = self.db.variants_attrs(e);
+                let enum_data = self.db.enum_data(e);
+
+                for (local_id, enum_var) in enum_data.variants.iter() {
+                    let variant_inhabitedness = self.visit_variant(
+                        EnumVariantId { parent: e, local_id }.into(),
+                        &enum_var.variant_data,
+                        subst,
+                        &vars_attrs[local_id],
+                        is_local,
+                    );
+                    match variant_inhabitedness {
+                        Break(VisiblyUninhabited) => continue,
+                        Continue(()) => return CONTINUE_OPAQUELY_INHABITED,
+                    }
+                }
+                BREAK_VISIBLY_UNINHABITED
+            }
+        }
+    }
+
+    fn visit_variant(
+        &mut self,
+        variant: VariantId,
+        variant_data: &VariantData,
+        subst: &Substitution,
+        attrs: &Attrs,
+        is_local: bool,
+    ) -> ControlFlow<VisiblyUninhabited> {
+        let non_exhaustive_field_list = attrs.by_key("non_exhaustive").exists();
+        if non_exhaustive_field_list && !is_local {
+            return CONTINUE_OPAQUELY_INHABITED;
+        }
+
+        let is_enum = matches!(variant, VariantId::EnumVariantId(..));
+        let field_tys = self.db.field_types(variant);
+        let field_vis = self.db.field_visibilities(variant);
+
+        for (fid, _) in variant_data.fields().iter() {
+            self.visit_field(field_vis[fid], &field_tys[fid], subst, is_enum)?;
+        }
+        CONTINUE_OPAQUELY_INHABITED
+    }
+
+    fn visit_field(
+        &mut self,
+        vis: Visibility,
+        ty: &Binders<Ty>,
+        subst: &Substitution,
+        is_enum: bool,
+    ) -> ControlFlow<VisiblyUninhabited> {
+        if is_enum || vis.is_visible_from(self.db.upcast(), self.target_mod) {
+            let ty = ty.clone().substitute(Interner, subst);
+            ty.visit_with(self, DebruijnIndex::INNERMOST)
+        } else {
+            CONTINUE_OPAQUELY_INHABITED
+        }
+    }
+}
+
+fn try_usize_const(c: &Const) -> Option<u128> {
+    let data = &c.data(Interner);
+    if data.ty.kind(Interner) != &TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::Usize)) {
+        return None;
+    }
+    match data.value {
+        ConstValue::Concrete(ConcreteConst { interned: ConstScalar::UInt(value) }) => Some(value),
+        _ => None,
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
index 5a5d610e360f..de4a5446e57f 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
@@ -14,6 +14,7 @@ mod chalk_db;
 mod chalk_ext;
 pub mod consteval;
 mod infer;
+mod inhabitedness;
 mod interner;
 mod lower;
 mod mapping;
@@ -195,20 +196,6 @@ pub(crate) fn make_binders<T: HasInterner<Interner = Interner>>(
     make_binders_with_count(db, usize::MAX, generics, value)
 }
 
-// FIXME: get rid of this
-pub fn make_canonical<T: HasInterner<Interner = Interner>>(
-    value: T,
-    kinds: impl IntoIterator<Item = TyVariableKind>,
-) -> Canonical<T> {
-    let kinds = kinds.into_iter().map(|tk| {
-        chalk_ir::CanonicalVarKind::new(
-            chalk_ir::VariableKind::Ty(tk),
-            chalk_ir::UniverseIndex::ROOT,
-        )
-    });
-    Canonical { value, binders: chalk_ir::CanonicalVarKinds::from_iter(Interner, kinds) }
-}
-
 // FIXME: get rid of this, just replace it by FnPointer
 /// A function signature as seen by type inference: Several parameter types and
 /// one return type.
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs
index 3f6d0844e9c1..532544fee595 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs
@@ -1,8 +1,8 @@
 //! Methods for lowering the HIR to types. There are two main cases here:
 //!
 //!  - Lowering a type reference like `&usize` or `Option<foo::bar::Baz>` to a
-//!    type: The entry point for this is `Ty::from_hir`.
-//!  - Building the type for an item: This happens through the `type_for_def` query.
+//!    type: The entry point for this is `TyLoweringContext::lower_ty`.
+//!  - Building the type for an item: This happens through the `ty` query.
 //!
 //! This usually involves resolving names, collecting generic arguments etc.
 use std::{
@@ -47,7 +47,7 @@ use crate::{
     consteval::{intern_const_scalar, path_to_const, unknown_const, unknown_const_as_generic},
     db::HirDatabase,
     make_binders,
-    mapping::ToChalk,
+    mapping::{from_chalk_trait_id, ToChalk},
     static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx,
     utils::Generics,
     utils::{all_super_trait_refs, associated_type_by_name_including_super_traits, generics},
@@ -332,7 +332,10 @@ impl<'a> TyLoweringContext<'a> {
             TypeRef::Macro(macro_call) => {
                 let (mut expander, recursion_start) = {
                     match RefMut::filter_map(self.expander.borrow_mut(), Option::as_mut) {
+                        // There already is an expander here, this means we are already recursing
                         Ok(expander) => (expander, false),
+                        // No expander was created yet, so we are at the start of the expansion recursion
+                        // and therefore have to create an expander.
                         Err(expander) => (
                             RefMut::map(expander, |it| {
                                 it.insert(Expander::new(
@@ -362,9 +365,14 @@ impl<'a> TyLoweringContext<'a> {
                                 .exit(self.db.upcast(), mark);
                             Some(ty)
                         }
-                        _ => None,
+                        _ => {
+                            drop(expander);
+                            None
+                        }
                     }
                 };
+
+                // drop the expander, resetting it to pre-recursion state
                 if recursion_start {
                     *self.expander.borrow_mut() = None;
                 }
@@ -973,14 +981,74 @@ impl<'a> TyLoweringContext<'a> {
 
     fn lower_dyn_trait(&self, bounds: &[Interned<TypeBound>]) -> Ty {
         let self_ty = TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(Interner);
+        // INVARIANT: The principal trait bound must come first. Others may be in any order but
+        // should be in the same order for the same set but possibly different order of bounds in
+        // the input.
+        // This invariant is used by `TyExt::dyn_trait()` and chalk.
         let bounds = self.with_shifted_in(DebruijnIndex::ONE, |ctx| {
-            QuantifiedWhereClauses::from_iter(
-                Interner,
-                bounds.iter().flat_map(|b| ctx.lower_type_bound(b, self_ty.clone(), false)),
-            )
+            let mut bounds: Vec<_> = bounds
+                .iter()
+                .flat_map(|b| ctx.lower_type_bound(b, self_ty.clone(), false))
+                .collect();
+
+            let mut multiple_regular_traits = false;
+            let mut multiple_same_projection = false;
+            bounds.sort_unstable_by(|lhs, rhs| {
+                use std::cmp::Ordering;
+                match (lhs.skip_binders(), rhs.skip_binders()) {
+                    (WhereClause::Implemented(lhs), WhereClause::Implemented(rhs)) => {
+                        let lhs_id = lhs.trait_id;
+                        let lhs_is_auto = ctx.db.trait_data(from_chalk_trait_id(lhs_id)).is_auto;
+                        let rhs_id = rhs.trait_id;
+                        let rhs_is_auto = ctx.db.trait_data(from_chalk_trait_id(rhs_id)).is_auto;
+
+                        if !lhs_is_auto && !rhs_is_auto {
+                            multiple_regular_traits = true;
+                        }
+                        // Note that the ordering here is important; this ensures the invariant
+                        // mentioned above.
+                        (lhs_is_auto, lhs_id).cmp(&(rhs_is_auto, rhs_id))
+                    }
+                    (WhereClause::Implemented(_), _) => Ordering::Less,
+                    (_, WhereClause::Implemented(_)) => Ordering::Greater,
+                    (WhereClause::AliasEq(lhs), WhereClause::AliasEq(rhs)) => {
+                        match (&lhs.alias, &rhs.alias) {
+                            (AliasTy::Projection(lhs_proj), AliasTy::Projection(rhs_proj)) => {
+                                // We only compare the `associated_ty_id`s. We shouldn't have
+                                // multiple bounds for an associated type in the correct Rust code,
+                                // and if we do, we error out.
+                                if lhs_proj.associated_ty_id == rhs_proj.associated_ty_id {
+                                    multiple_same_projection = true;
+                                }
+                                lhs_proj.associated_ty_id.cmp(&rhs_proj.associated_ty_id)
+                            }
+                            // We don't produce `AliasTy::Opaque`s yet.
+                            _ => unreachable!(),
+                        }
+                    }
+                    // We don't produce `WhereClause::{TypeOutlives, LifetimeOutlives}` yet.
+                    _ => unreachable!(),
+                }
+            });
+
+            if multiple_regular_traits || multiple_same_projection {
+                return None;
+            }
+
+            // As multiple occurrences of the same auto traits *are* permitted, we dedulicate the
+            // bounds. We shouldn't have repeated elements besides auto traits at this point.
+            bounds.dedup();
+
+            Some(QuantifiedWhereClauses::from_iter(Interner, bounds))
         });
-        let bounds = crate::make_single_type_binders(bounds);
-        TyKind::Dyn(DynTy { bounds, lifetime: static_lifetime() }).intern(Interner)
+
+        if let Some(bounds) = bounds {
+            let bounds = crate::make_single_type_binders(bounds);
+            TyKind::Dyn(DynTy { bounds, lifetime: static_lifetime() }).intern(Interner)
+        } else {
+            // FIXME: report error (additional non-auto traits or associated type rebound)
+            TyKind::Error.intern(Interner)
+        }
     }
 
     fn lower_impl_trait(
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/method_resolution.rs b/src/tools/rust-analyzer/crates/hir-ty/src/method_resolution.rs
index 9a63d5013b46..41fcef73d9be 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/method_resolution.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/method_resolution.rs
@@ -914,22 +914,10 @@ fn iterate_trait_method_candidates(
     let db = table.db;
     let env = table.trait_env.clone();
     let self_is_array = matches!(self_ty.kind(Interner), chalk_ir::TyKind::Array(..));
-    // if ty is `dyn Trait`, the trait doesn't need to be in scope
-    let inherent_trait =
-        self_ty.dyn_trait().into_iter().flat_map(|t| all_super_traits(db.upcast(), t));
-    let env_traits = matches!(self_ty.kind(Interner), TyKind::Placeholder(_))
-        // if we have `T: Trait` in the param env, the trait doesn't need to be in scope
-        .then(|| {
-            env.traits_in_scope_from_clauses(self_ty.clone())
-                .flat_map(|t| all_super_traits(db.upcast(), t))
-        })
-        .into_iter()
-        .flatten();
-    let traits = inherent_trait.chain(env_traits).chain(traits_in_scope.iter().copied());
 
     let canonical_self_ty = table.canonicalize(self_ty.clone()).value;
 
-    'traits: for t in traits {
+    'traits: for &t in traits_in_scope {
         let data = db.trait_data(t);
 
         // Traits annotated with `#[rustc_skip_array_during_method_dispatch]` are skipped during
@@ -979,6 +967,44 @@ fn iterate_inherent_methods(
 ) -> ControlFlow<()> {
     let db = table.db;
     let env = table.trait_env.clone();
+
+    // For trait object types and placeholder types with trait bounds, the methods of the trait and
+    // its super traits are considered inherent methods. This matters because these methods have
+    // higher priority than the other traits' methods, which would be considered in
+    // `iterate_trait_method_candidates()` only after this function.
+    match self_ty.kind(Interner) {
+        TyKind::Placeholder(_) => {
+            let env = table.trait_env.clone();
+            let traits = env
+                .traits_in_scope_from_clauses(self_ty.clone())
+                .flat_map(|t| all_super_traits(db.upcast(), t));
+            iterate_inherent_trait_methods(
+                self_ty,
+                table,
+                name,
+                receiver_ty,
+                receiver_adjustments.clone(),
+                callback,
+                traits,
+            )?;
+        }
+        TyKind::Dyn(_) => {
+            if let Some(principal_trait) = self_ty.dyn_trait() {
+                let traits = all_super_traits(db.upcast(), principal_trait);
+                iterate_inherent_trait_methods(
+                    self_ty,
+                    table,
+                    name,
+                    receiver_ty,
+                    receiver_adjustments.clone(),
+                    callback,
+                    traits.into_iter(),
+                )?;
+            }
+        }
+        _ => {}
+    }
+
     let def_crates = match def_crates(db, self_ty, env.krate) {
         Some(k) => k,
         None => return ControlFlow::Continue(()),
@@ -1020,6 +1046,28 @@ fn iterate_inherent_methods(
     }
     return ControlFlow::Continue(());
 
+    fn iterate_inherent_trait_methods(
+        self_ty: &Ty,
+        table: &mut InferenceTable<'_>,
+        name: Option<&Name>,
+        receiver_ty: Option<&Ty>,
+        receiver_adjustments: Option<ReceiverAdjustments>,
+        callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+        traits: impl Iterator<Item = TraitId>,
+    ) -> ControlFlow<()> {
+        let db = table.db;
+        for t in traits {
+            let data = db.trait_data(t);
+            for &(_, item) in data.items.iter() {
+                // We don't pass `visible_from_module` as all trait items should be visible.
+                if is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
+                    callback(receiver_adjustments.clone().unwrap_or_default(), item)?;
+                }
+            }
+        }
+        ControlFlow::Continue(())
+    }
+
     fn impls_for_self_ty(
         impls: &InherentImpls,
         self_ty: &Ty,
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/macros.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/macros.rs
index a1ab6060e790..b3adafaafd38 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/macros.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/macros.rs
@@ -193,8 +193,6 @@ fn expr_macro_def_expanded_in_various_places() {
             !0..6 '1isize': isize
             !0..6 '1isize': isize
             !0..6 '1isize': isize
-            !0..6 '1isize': isize
-            !0..6 '1isize': isize
             39..442 '{     ...!(); }': ()
             73..94 'spam!(...am!())': {unknown}
             100..119 'for _ ...!() {}': ()
@@ -276,8 +274,6 @@ fn expr_macro_rules_expanded_in_various_places() {
             !0..6 '1isize': isize
             !0..6 '1isize': isize
             !0..6 '1isize': isize
-            !0..6 '1isize': isize
-            !0..6 '1isize': isize
             53..456 '{     ...!(); }': ()
             87..108 'spam!(...am!())': {unknown}
             114..133 'for _ ...!() {}': ()
@@ -312,7 +308,6 @@ fn expr_macro_expanded_in_stmts() {
         }
         "#,
         expect![[r#"
-            !0..8 'leta=();': ()
             !3..4 'a': ()
             !5..7 '()': ()
             57..84 '{     ...); } }': ()
@@ -321,7 +316,7 @@ fn expr_macro_expanded_in_stmts() {
 }
 
 #[test]
-fn recurisve_macro_expanded_in_stmts() {
+fn recursive_macro_expanded_in_stmts() {
     check_infer(
         r#"
         macro_rules! ng {
@@ -340,11 +335,6 @@ fn recurisve_macro_expanded_in_stmts() {
         }
         "#,
         expect![[r#"
-            !0..7 'leta=3;': ()
-            !0..13 'ng!{[leta=3]}': ()
-            !0..13 'ng!{[leta=]3}': ()
-            !0..13 'ng!{[leta]=3}': ()
-            !0..13 'ng!{[let]a=3}': ()
             !3..4 'a': i32
             !5..6 '3': i32
             196..237 '{     ...= a; }': ()
@@ -369,8 +359,6 @@ fn recursive_inner_item_macro_rules() {
         "#,
         expect![[r#"
             !0..1 '1': i32
-            !0..7 'mac!($)': ()
-            !0..26 'macro_...>{1};}': ()
             107..143 '{     ...!(); }': ()
             129..130 'a': i32
         "#]],
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/method_resolution.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/method_resolution.rs
index 81588a7c4ffd..ac8edb841a58 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/method_resolution.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/method_resolution.rs
@@ -1218,6 +1218,40 @@ fn main() {
     );
 }
 
+#[test]
+fn dyn_trait_method_priority() {
+    check_types(
+        r#"
+//- minicore: from
+trait Trait {
+    fn into(&self) -> usize { 0 }
+}
+
+fn foo(a: &dyn Trait) {
+    let _ = a.into();
+      //^usize
+}
+        "#,
+    );
+}
+
+#[test]
+fn trait_method_priority_for_placeholder_type() {
+    check_types(
+        r#"
+//- minicore: from
+trait Trait {
+    fn into(&self) -> usize { 0 }
+}
+
+fn foo<T: Trait>(a: &T) {
+    let _ = a.into();
+      //^usize
+}
+        "#,
+    );
+}
+
 #[test]
 fn autoderef_visibility_field() {
     check(
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression.rs
index c7895db1afbf..23e51a9c16a5 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/regression.rs
@@ -573,7 +573,6 @@ fn issue_6811() {
         }
         "#,
         expect![[r#"
-            !0..16 'let_a=...t_b=1;': ()
             !3..5 '_a': i32
             !6..7 '1': i32
             !11..13 '_b': i32
@@ -1679,7 +1678,6 @@ fn main() {
 
 #[test]
 fn trailing_empty_macro() {
-    cov_mark::check!(empty_macro_in_trailing_position_is_removed);
     check_no_mismatches(
         r#"
 macro_rules! m2 {
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/simple.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/simple.rs
index 5b08f552109e..4ea103e5d9ec 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/simple.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/simple.rs
@@ -2549,7 +2549,6 @@ impl B for Astruct {}
         expect![[r#"
             569..573 'self': Box<[T], A>
             602..634 '{     ...     }': Vec<T, A>
-            612..628 'unimpl...ted!()': Vec<T, A>
             648..761 '{     ...t]); }': ()
             658..661 'vec': Vec<i32, Global>
             664..679 '<[_]>::into_vec': fn into_vec<i32, Global>(Box<[i32], Global>) -> Vec<i32, Global>
@@ -3070,3 +3069,17 @@ fn main() {
         "#,
     );
 }
+
+#[test]
+fn nested_break() {
+    check_no_mismatches(
+        r#"
+fn func() {
+    let int = loop {
+        break 0;
+        break (break 0);
+    };
+}
+    "#,
+    );
+}
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs
index 0f37970e2b38..21a86319763f 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs
@@ -3833,3 +3833,123 @@ fn test() {
 "#,
     )
 }
+
+#[test]
+fn dyn_multiple_auto_traits_in_different_order() {
+    check_no_mismatches(
+        r#"
+auto trait Send {}
+auto trait Sync {}
+
+fn f(t: &(dyn Sync + Send)) {}
+fn g(t: &(dyn Send + Sync)) {
+    f(t);
+}
+        "#,
+    );
+
+    check_no_mismatches(
+        r#"
+auto trait Send {}
+auto trait Sync {}
+trait T {}
+
+fn f(t: &(dyn T + Send + Sync)) {}
+fn g(t: &(dyn Sync + T + Send)) {
+    f(t);
+}
+        "#,
+    );
+
+    check_infer_with_mismatches(
+        r#"
+auto trait Send {}
+auto trait Sync {}
+trait T1 {}
+trait T2 {}
+
+fn f(t: &(dyn T1 + T2 + Send + Sync)) {}
+fn g(t: &(dyn Sync + T2 + T1 + Send)) {
+    f(t);
+}
+        "#,
+        expect![[r#"
+            68..69 't': &{unknown}
+            101..103 '{}': ()
+            109..110 't': &{unknown}
+            142..155 '{     f(t); }': ()
+            148..149 'f': fn f(&{unknown})
+            148..152 'f(t)': ()
+            150..151 't': &{unknown}
+        "#]],
+    );
+
+    check_no_mismatches(
+        r#"
+auto trait Send {}
+auto trait Sync {}
+trait T {
+    type Proj: Send + Sync;
+}
+
+fn f(t: &(dyn T<Proj = ()>  + Send + Sync)) {}
+fn g(t: &(dyn Sync + T<Proj = ()> + Send)) {
+    f(t);
+}
+        "#,
+    );
+}
+
+#[test]
+fn dyn_multiple_projection_bounds() {
+    check_no_mismatches(
+        r#"
+trait Trait {
+    type T;
+    type U;
+}
+
+fn f(t: &dyn Trait<T = (), U = ()>) {}
+fn g(t: &dyn Trait<U = (), T = ()>) {
+    f(t);
+}
+        "#,
+    );
+
+    check_types(
+        r#"
+trait Trait {
+    type T;
+}
+
+fn f(t: &dyn Trait<T = (), T = ()>) {}
+   //^&{unknown}
+        "#,
+    );
+}
+
+#[test]
+fn dyn_duplicate_auto_trait() {
+    check_no_mismatches(
+        r#"
+auto trait Send {}
+
+fn f(t: &(dyn Send + Send)) {}
+fn g(t: &(dyn Send)) {
+    f(t);
+}
+        "#,
+    );
+
+    check_no_mismatches(
+        r#"
+auto trait Send {}
+trait T {}
+
+fn f(t: &(dyn T + Send + Send)) {}
+fn g(t: &(dyn T + Send)) {
+    f(t);
+}
+        "#,
+    );
+}
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/traits.rs b/src/tools/rust-analyzer/crates/hir-ty/src/traits.rs
index 77afeb3217dd..372c3a3cca64 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/traits.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/traits.rs
@@ -1,6 +1,6 @@
 //! Trait solving using Chalk.
 
-use std::env::var;
+use std::{env::var, sync::Arc};
 
 use chalk_ir::GoalData;
 use chalk_recursive::Cache;
@@ -12,8 +12,9 @@ use stdx::panic_context;
 use syntax::SmolStr;
 
 use crate::{
-    db::HirDatabase, AliasEq, AliasTy, Canonical, DomainGoal, Goal, Guidance, InEnvironment,
-    Interner, Solution, TraitRefExt, Ty, TyKind, WhereClause,
+    db::HirDatabase, infer::unify::InferenceTable, AliasEq, AliasTy, Canonical, DomainGoal, Goal,
+    Guidance, InEnvironment, Interner, ProjectionTy, Solution, TraitRefExt, Ty, TyKind,
+    WhereClause,
 };
 
 /// This controls how much 'time' we give the Chalk solver before giving up.
@@ -64,6 +65,16 @@ impl TraitEnvironment {
     }
 }
 
+pub(crate) fn normalize_projection_query(
+    db: &dyn HirDatabase,
+    projection: ProjectionTy,
+    env: Arc<TraitEnvironment>,
+) -> Ty {
+    let mut table = InferenceTable::new(db, env);
+    let ty = table.normalize_projection_ty(projection);
+    table.resolve_completely(ty)
+}
+
 /// Solve a trait goal using Chalk.
 pub(crate) fn trait_solve_query(
     db: &dyn HirDatabase,
diff --git a/src/tools/rust-analyzer/crates/hir/src/diagnostics.rs b/src/tools/rust-analyzer/crates/hir/src/diagnostics.rs
index 50374f4b3fe4..5edc16d8bce9 100644
--- a/src/tools/rust-analyzer/crates/hir/src/diagnostics.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/diagnostics.rs
@@ -124,6 +124,7 @@ pub struct NoSuchField {
 #[derive(Debug)]
 pub struct BreakOutsideOfLoop {
     pub expr: InFile<AstPtr<ast::Expr>>,
+    pub is_break: bool,
 }
 
 #[derive(Debug)]
diff --git a/src/tools/rust-analyzer/crates/hir/src/lib.rs b/src/tools/rust-analyzer/crates/hir/src/lib.rs
index 6dccf2ed20b8..d2717c566547 100644
--- a/src/tools/rust-analyzer/crates/hir/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/lib.rs
@@ -63,10 +63,9 @@ use hir_ty::{
     primitive::UintTy,
     subst_prefix,
     traits::FnTrait,
-    AliasEq, AliasTy, BoundVar, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast,
-    ClosureId, DebruijnIndex, GenericArgData, InEnvironment, Interner, ParamKind,
-    QuantifiedWhereClause, Scalar, Solution, Substitution, TraitEnvironment, TraitRefExt, Ty,
-    TyBuilder, TyDefId, TyExt, TyKind, TyVariableKind, WhereClause,
+    AliasTy, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast, ClosureId,
+    GenericArgData, Interner, ParamKind, QuantifiedWhereClause, Scalar, Substitution,
+    TraitEnvironment, TraitRefExt, Ty, TyBuilder, TyDefId, TyExt, TyKind, WhereClause,
 };
 use itertools::Itertools;
 use nameres::diagnostics::DefDiagnosticKind;
@@ -582,8 +581,13 @@ impl Module {
 
     /// Finds a path that can be used to refer to the given item from within
     /// this module, if possible.
-    pub fn find_use_path(self, db: &dyn DefDatabase, item: impl Into<ItemInNs>) -> Option<ModPath> {
-        hir_def::find_path::find_path(db, item.into().into(), self.into())
+    pub fn find_use_path(
+        self,
+        db: &dyn DefDatabase,
+        item: impl Into<ItemInNs>,
+        prefer_no_std: bool,
+    ) -> Option<ModPath> {
+        hir_def::find_path::find_path(db, item.into().into(), self.into(), prefer_no_std)
     }
 
     /// Finds a path that can be used to refer to the given item from within
@@ -593,8 +597,15 @@ impl Module {
         db: &dyn DefDatabase,
         item: impl Into<ItemInNs>,
         prefix_kind: PrefixKind,
+        prefer_no_std: bool,
     ) -> Option<ModPath> {
-        hir_def::find_path::find_path_prefixed(db, item.into().into(), self.into(), prefix_kind)
+        hir_def::find_path::find_path_prefixed(
+            db,
+            item.into().into(),
+            self.into(),
+            prefix_kind,
+            prefer_no_std,
+        )
     }
 }
 
@@ -1216,11 +1227,11 @@ impl DefWithBody {
                     let field = source_map.field_syntax(*expr);
                     acc.push(NoSuchField { field }.into())
                 }
-                hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr } => {
+                &hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr, is_break } => {
                     let expr = source_map
-                        .expr_syntax(*expr)
+                        .expr_syntax(expr)
                         .expect("break outside of loop in synthetic syntax");
-                    acc.push(BreakOutsideOfLoop { expr }.into())
+                    acc.push(BreakOutsideOfLoop { expr, is_break }.into())
                 }
                 hir_ty::InferenceDiagnostic::MismatchedArgCount { call_expr, expected, found } => {
                     match source_map.expr_syntax(*call_expr) {
@@ -2880,27 +2891,12 @@ impl Type {
                 }
             })
             .build();
-        let goal = hir_ty::make_canonical(
-            InEnvironment::new(
-                &self.env.env,
-                AliasEq {
-                    alias: AliasTy::Projection(projection),
-                    ty: TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0))
-                        .intern(Interner),
-                }
-                .cast(Interner),
-            ),
-            [TyVariableKind::General].into_iter(),
-        );
 
-        match db.trait_solve(self.env.krate, goal)? {
-            Solution::Unique(s) => s
-                .value
-                .subst
-                .as_slice(Interner)
-                .first()
-                .map(|ty| self.derived(ty.assert_ty_ref(Interner).clone())),
-            Solution::Ambig(_) => None,
+        let ty = db.normalize_projection(projection, self.env.clone());
+        if ty.is_unknown() {
+            None
+        } else {
+            Some(self.derived(ty))
         }
     }
 
diff --git a/src/tools/rust-analyzer/crates/hir/src/source_analyzer.rs b/src/tools/rust-analyzer/crates/hir/src/source_analyzer.rs
index bd35af06e23e..342912b678a1 100644
--- a/src/tools/rust-analyzer/crates/hir/src/source_analyzer.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/source_analyzer.rs
@@ -140,11 +140,19 @@ impl SourceAnalyzer {
     ) -> Option<InFile<ast::Expr>> {
         let macro_file = self.body_source_map()?.node_macro_file(expr.as_ref())?;
         let expanded = db.parse_or_expand(macro_file)?;
-
-        let res = match ast::MacroCall::cast(expanded.clone()) {
-            Some(call) => self.expand_expr(db, InFile::new(macro_file, call))?,
-            _ => InFile::new(macro_file, ast::Expr::cast(expanded)?),
+        let res = if let Some(stmts) = ast::MacroStmts::cast(expanded.clone()) {
+            match stmts.expr()? {
+                ast::Expr::MacroExpr(mac) => {
+                    self.expand_expr(db, InFile::new(macro_file, mac.macro_call()?))?
+                }
+                expr => InFile::new(macro_file, expr),
+            }
+        } else if let Some(call) = ast::MacroCall::cast(expanded.clone()) {
+            self.expand_expr(db, InFile::new(macro_file, call))?
+        } else {
+            InFile::new(macro_file, ast::Expr::cast(expanded)?)
         };
+
         Some(res)
     }
 
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/assist_config.rs b/src/tools/rust-analyzer/crates/ide-assists/src/assist_config.rs
index d4d148c77457..60d1588a44e5 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/assist_config.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/assist_config.rs
@@ -13,4 +13,5 @@ pub struct AssistConfig {
     pub snippet_cap: Option<SnippetCap>,
     pub allowed: Option<Vec<AssistKind>>,
     pub insert_use: InsertUseConfig,
+    pub prefer_no_std: bool,
 }
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/add_missing_match_arms.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/add_missing_match_arms.rs
index b16f6fe03ae8..73f4db4e5ff2 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/add_missing_match_arms.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/add_missing_match_arms.rs
@@ -5,6 +5,7 @@ use hir::{Adt, Crate, HasAttrs, HasSource, ModuleDef, Semantics};
 use ide_db::RootDatabase;
 use ide_db::{famous_defs::FamousDefs, helpers::mod_path_to_ast};
 use itertools::Itertools;
+use syntax::ast::edit_in_place::Removable;
 use syntax::ast::{self, make, AstNode, HasName, MatchArmList, MatchExpr, Pat};
 
 use crate::{
@@ -86,7 +87,7 @@ pub(crate) fn add_missing_match_arms(acc: &mut Assists, ctx: &AssistContext<'_>)
             .into_iter()
             .filter_map(|variant| {
                 Some((
-                    build_pat(ctx.db(), module, variant)?,
+                    build_pat(ctx.db(), module, variant, ctx.config.prefer_no_std)?,
                     variant.should_be_hidden(ctx.db(), module.krate()),
                 ))
             })
@@ -131,8 +132,9 @@ pub(crate) fn add_missing_match_arms(acc: &mut Assists, ctx: &AssistContext<'_>)
                 let is_hidden = variants
                     .iter()
                     .any(|variant| variant.should_be_hidden(ctx.db(), module.krate()));
-                let patterns =
-                    variants.into_iter().filter_map(|variant| build_pat(ctx.db(), module, variant));
+                let patterns = variants.into_iter().filter_map(|variant| {
+                    build_pat(ctx.db(), module, variant, ctx.config.prefer_no_std)
+                });
 
                 (ast::Pat::from(make::tuple_pat(patterns)), is_hidden)
             })
@@ -348,10 +350,16 @@ fn resolve_tuple_of_enum_def(
         .collect()
 }
 
-fn build_pat(db: &RootDatabase, module: hir::Module, var: ExtendedVariant) -> Option<ast::Pat> {
+fn build_pat(
+    db: &RootDatabase,
+    module: hir::Module,
+    var: ExtendedVariant,
+    prefer_no_std: bool,
+) -> Option<ast::Pat> {
     match var {
         ExtendedVariant::Variant(var) => {
-            let path = mod_path_to_ast(&module.find_use_path(db, ModuleDef::from(var))?);
+            let path =
+                mod_path_to_ast(&module.find_use_path(db, ModuleDef::from(var), prefer_no_std)?);
 
             // FIXME: use HIR for this; it doesn't currently expose struct vs. tuple vs. unit variants though
             let pat: ast::Pat = match var.source(db)?.value.kind() {
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/auto_import.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/auto_import.rs
index 949cf3167a8a..e257218ba937 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/auto_import.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/auto_import.rs
@@ -89,8 +89,11 @@ use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
 // ```
 pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
     let (import_assets, syntax_under_caret) = find_importable_node(ctx)?;
-    let mut proposed_imports =
-        import_assets.search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind);
+    let mut proposed_imports = import_assets.search_for_imports(
+        &ctx.sema,
+        ctx.config.insert_use.prefix_kind,
+        ctx.config.prefer_no_std,
+    );
     if proposed_imports.is_empty() {
         return None;
     }
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_into_to_from.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_into_to_from.rs
index 30f6dd41a1d6..95d11abe8bc0 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_into_to_from.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_into_to_from.rs
@@ -50,7 +50,7 @@ pub(crate) fn convert_into_to_from(acc: &mut Assists, ctx: &AssistContext<'_>) -
             _ => return None,
         };
 
-        mod_path_to_ast(&module.find_use_path(ctx.db(), src_type_def)?)
+        mod_path_to_ast(&module.find_use_path(ctx.db(), src_type_def, ctx.config.prefer_no_std)?)
     };
 
     let dest_type = match &ast_trait {
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_two_arm_bool_match_to_matches_macro.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_two_arm_bool_match_to_matches_macro.rs
new file mode 100644
index 000000000000..54a7f480a4e4
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/convert_two_arm_bool_match_to_matches_macro.rs
@@ -0,0 +1,294 @@
+use syntax::ast::{self, AstNode};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: convert_two_arm_bool_match_to_matches_macro
+//
+// Convert 2-arm match that evaluates to a boolean into the equivalent matches! invocation.
+//
+// ```
+// fn main() {
+//     match scrutinee$0 {
+//         Some(val) if val.cond() => true,
+//         _ => false,
+//     }
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     matches!(scrutinee, Some(val) if val.cond())
+// }
+// ```
+pub(crate) fn convert_two_arm_bool_match_to_matches_macro(
+    acc: &mut Assists,
+    ctx: &AssistContext<'_>,
+) -> Option<()> {
+    let match_expr = ctx.find_node_at_offset::<ast::MatchExpr>()?;
+    let match_arm_list = match_expr.match_arm_list()?;
+    let mut arms = match_arm_list.arms();
+    let first_arm = arms.next()?;
+    let second_arm = arms.next()?;
+    if arms.next().is_some() {
+        cov_mark::hit!(non_two_arm_match);
+        return None;
+    }
+    let first_arm_expr = first_arm.expr();
+    let second_arm_expr = second_arm.expr();
+
+    let invert_matches = if is_bool_literal_expr(&first_arm_expr, true)
+        && is_bool_literal_expr(&second_arm_expr, false)
+    {
+        false
+    } else if is_bool_literal_expr(&first_arm_expr, false)
+        && is_bool_literal_expr(&second_arm_expr, true)
+    {
+        true
+    } else {
+        cov_mark::hit!(non_invert_bool_literal_arms);
+        return None;
+    };
+
+    let target_range = ctx.sema.original_range(match_expr.syntax()).range;
+    let expr = match_expr.expr()?;
+
+    acc.add(
+        AssistId("convert_two_arm_bool_match_to_matches_macro", AssistKind::RefactorRewrite),
+        "Convert to matches!",
+        target_range,
+        |builder| {
+            let mut arm_str = String::new();
+            if let Some(ref pat) = first_arm.pat() {
+                arm_str += &pat.to_string();
+            }
+            if let Some(ref guard) = first_arm.guard() {
+                arm_str += &format!(" {}", &guard.to_string());
+            }
+            if invert_matches {
+                builder.replace(target_range, format!("!matches!({}, {})", expr, arm_str));
+            } else {
+                builder.replace(target_range, format!("matches!({}, {})", expr, arm_str));
+            }
+        },
+    )
+}
+
+fn is_bool_literal_expr(expr: &Option<ast::Expr>, expect_bool: bool) -> bool {
+    if let Some(ast::Expr::Literal(lit)) = expr {
+        if let ast::LiteralKind::Bool(b) = lit.kind() {
+            return b == expect_bool;
+        }
+    }
+
+    return false;
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::convert_two_arm_bool_match_to_matches_macro;
+
+    #[test]
+    fn not_applicable_outside_of_range_left() {
+        check_assist_not_applicable(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    $0 match a {
+        Some(_val) => true,
+        _ => false
+    }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_non_two_arm_match() {
+        cov_mark::check!(non_two_arm_match);
+        check_assist_not_applicable(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(3) => true,
+        Some(4) => true,
+        _ => false
+    }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_non_bool_literal_arms() {
+        cov_mark::check!(non_invert_bool_literal_arms);
+        check_assist_not_applicable(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(val) => val == 3,
+        _ => false
+    }
+}
+        "#,
+        );
+    }
+    #[test]
+    fn not_applicable_both_false_arms() {
+        cov_mark::check!(non_invert_bool_literal_arms);
+        check_assist_not_applicable(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(val) => false,
+        _ => false
+    }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_both_true_arms() {
+        cov_mark::check!(non_invert_bool_literal_arms);
+        check_assist_not_applicable(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(val) => true,
+        _ => true
+    }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn convert_simple_case() {
+        check_assist(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(_val) => true,
+        _ => false
+    }
+}
+"#,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    matches!(a, Some(_val))
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn convert_simple_invert_case() {
+        check_assist(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(_val) => false,
+        _ => true
+    }
+}
+"#,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    !matches!(a, Some(_val))
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn convert_with_guard_case() {
+        check_assist(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(val) if val > 3 => true,
+        _ => false
+    }
+}
+"#,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    matches!(a, Some(val) if val > 3)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn convert_enum_match_cases() {
+        check_assist(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+enum X { A, B }
+
+fn foo(a: X) -> bool {
+    match a$0 {
+        X::A => true,
+        _ => false
+    }
+}
+"#,
+            r#"
+enum X { A, B }
+
+fn foo(a: X) -> bool {
+    matches!(a, X::A)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn convert_target_simple() {
+        check_assist_target(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+fn foo(a: Option<u32>) -> bool {
+    match a$0 {
+        Some(val) => true,
+        _ => false
+    }
+}
+"#,
+            r#"match a {
+        Some(val) => true,
+        _ => false
+    }"#,
+        );
+    }
+
+    #[test]
+    fn convert_target_complex() {
+        check_assist_target(
+            convert_two_arm_bool_match_to_matches_macro,
+            r#"
+enum E { X, Y }
+
+fn main() {
+    match E::X$0 {
+        E::X => true,
+        _ => false,
+    }
+}
+"#,
+            "match E::X {
+        E::X => true,
+        _ => false,
+    }",
+        );
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_function.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_function.rs
index 52a55ead3af9..d6c8ea785f84 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_function.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_function.rs
@@ -152,6 +152,7 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext<'_>) -> Op
                         ctx.sema.db,
                         ModuleDef::from(control_flow_enum),
                         ctx.config.insert_use.prefix_kind,
+                        ctx.config.prefer_no_std,
                     );
 
                     if let Some(mod_path) = mod_path {
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_struct_from_enum_variant.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_struct_from_enum_variant.rs
index dfb565212646..8d5cab283d06 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_struct_from_enum_variant.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -101,21 +101,22 @@ pub(crate) fn extract_struct_from_enum_variant(
                 });
             }
 
-            let indent = enum_ast.indent_level();
             let generic_params = enum_ast
                 .generic_param_list()
                 .and_then(|known_generics| extract_generic_params(&known_generics, &field_list));
             let generics = generic_params.as_ref().map(|generics| generics.clone_for_update());
             let def =
                 create_struct_def(variant_name.clone(), &variant, &field_list, generics, &enum_ast);
+
+            let enum_ast = variant.parent_enum();
+            let indent = enum_ast.indent_level();
             def.reindent_to(indent);
 
-            let start_offset = &variant.parent_enum().syntax().clone();
-            ted::insert_all_raw(
-                ted::Position::before(start_offset),
+            ted::insert_all(
+                ted::Position::before(enum_ast.syntax()),
                 vec![
                     def.syntax().clone().into(),
-                    make::tokens::whitespace(&format!("\n\n{}", indent)).into(),
+                    make::tokens::whitespace(&format!("\n\n{indent}")).into(),
                 ],
             );
 
@@ -227,7 +228,7 @@ fn tag_generics_in_variant(ty: &ast::Type, generics: &mut [(ast::GenericParam, b
 }
 
 fn create_struct_def(
-    variant_name: ast::Name,
+    name: ast::Name,
     variant: &ast::Variant,
     field_list: &Either<ast::RecordFieldList, ast::TupleFieldList>,
     generics: Option<ast::GenericParamList>,
@@ -269,43 +270,27 @@ fn create_struct_def(
             field_list.into()
         }
     };
-
     field_list.reindent_to(IndentLevel::single());
 
-    let strukt = make::struct_(enum_vis, variant_name, generics, field_list).clone_for_update();
+    let strukt = make::struct_(enum_vis, name, generics, field_list).clone_for_update();
 
-    // FIXME: Consider making this an actual function somewhere (like in `AttrsOwnerEdit`) after some deliberation
-    let attrs_and_docs = |node: &SyntaxNode| {
-        let mut select_next_ws = false;
-        node.children_with_tokens().filter(move |child| {
-            let accept = match child.kind() {
-                ATTR | COMMENT => {
-                    select_next_ws = true;
-                    return true;
-                }
-                WHITESPACE if select_next_ws => true,
-                _ => false,
-            };
-            select_next_ws = false;
-
-            accept
-        })
-    };
-
-    // copy attributes & comments from variant
-    let variant_attrs = attrs_and_docs(variant.syntax())
-        .map(|tok| match tok.kind() {
-            WHITESPACE => make::tokens::single_newline().into(),
-            _ => tok,
-        })
-        .collect();
-    ted::insert_all(ted::Position::first_child_of(strukt.syntax()), variant_attrs);
+    // take comments from variant
+    ted::insert_all(
+        ted::Position::first_child_of(strukt.syntax()),
+        take_all_comments(variant.syntax()),
+    );
 
     // copy attributes from enum
     ted::insert_all(
         ted::Position::first_child_of(strukt.syntax()),
-        enum_.attrs().map(|it| it.syntax().clone_for_update().into()).collect(),
+        enum_
+            .attrs()
+            .flat_map(|it| {
+                vec![it.syntax().clone_for_update().into(), make::tokens::single_newline().into()]
+            })
+            .collect(),
     );
+
     strukt
 }
 
@@ -346,16 +331,48 @@ fn update_variant(variant: &ast::Variant, generics: Option<ast::GenericParamList
         })
         .unwrap_or_else(|| make::ty(&name.text()));
 
+    // change from a record to a tuple field list
     let tuple_field = make::tuple_field(None, ty);
-    let replacement = make::variant(
-        name,
-        Some(ast::FieldList::TupleFieldList(make::tuple_field_list(iter::once(tuple_field)))),
-    )
-    .clone_for_update();
-    ted::replace(variant.syntax(), replacement.syntax());
+    let field_list = make::tuple_field_list(iter::once(tuple_field)).clone_for_update();
+    ted::replace(variant.field_list()?.syntax(), field_list.syntax());
+
+    // remove any ws after the name
+    if let Some(ws) = name
+        .syntax()
+        .siblings_with_tokens(syntax::Direction::Next)
+        .find_map(|tok| tok.into_token().filter(|tok| tok.kind() == WHITESPACE))
+    {
+        ted::remove(SyntaxElement::Token(ws));
+    }
+
     Some(())
 }
 
+// Note: this also detaches whitespace after comments,
+// since `SyntaxNode::splice_children` (and by extension `ted::insert_all_raw`)
+// detaches nodes. If we only took the comments, we'd leave behind the old whitespace.
+fn take_all_comments(node: &SyntaxNode) -> Vec<SyntaxElement> {
+    let mut remove_next_ws = false;
+    node.children_with_tokens()
+        .filter_map(move |child| match child.kind() {
+            COMMENT => {
+                remove_next_ws = true;
+                child.detach();
+                Some(child)
+            }
+            WHITESPACE if remove_next_ws => {
+                remove_next_ws = false;
+                child.detach();
+                Some(make::tokens::single_newline().into())
+            }
+            _ => {
+                remove_next_ws = false;
+                None
+            }
+        })
+        .collect()
+}
+
 fn apply_references(
     insert_use_cfg: InsertUseConfig,
     segment: ast::PathSegment,
@@ -392,6 +409,7 @@ fn process_references(
                     ctx.sema.db,
                     *enum_module_def,
                     ctx.config.insert_use.prefix_kind,
+                    ctx.config.prefer_no_std,
                 );
                 if let Some(mut mod_path) = mod_path {
                     mod_path.pop_segment();
@@ -480,10 +498,14 @@ enum En<T> { Var(Var<T>) }"#,
     fn test_extract_struct_carries_over_attributes() {
         check_assist(
             extract_struct_from_enum_variant,
-            r#"#[derive(Debug)]
+            r#"
+#[derive(Debug)]
 #[derive(Clone)]
 enum Enum { Variant{ field: u32$0 } }"#,
-            r#"#[derive(Debug)]#[derive(Clone)] struct Variant{ field: u32 }
+            r#"
+#[derive(Debug)]
+#[derive(Clone)]
+struct Variant{ field: u32 }
 
 #[derive(Debug)]
 #[derive(Clone)]
@@ -614,7 +636,7 @@ enum A { One(One) }"#,
     }
 
     #[test]
-    fn test_extract_struct_keep_comments_and_attrs_on_variant_struct() {
+    fn test_extract_struct_move_struct_variant_comments() {
         check_assist(
             extract_struct_from_enum_variant,
             r#"
@@ -631,19 +653,19 @@ enum A {
 /* comment */
 // other
 /// comment
-#[attr]
 struct One{
     a: u32
 }
 
 enum A {
+    #[attr]
     One(One)
 }"#,
         );
     }
 
     #[test]
-    fn test_extract_struct_keep_comments_and_attrs_on_variant_tuple() {
+    fn test_extract_struct_move_tuple_variant_comments() {
         check_assist(
             extract_struct_from_enum_variant,
             r#"
@@ -658,10 +680,10 @@ enum A {
 /* comment */
 // other
 /// comment
-#[attr]
 struct One(u32, u32);
 
 enum A {
+    #[attr]
     One(One)
 }"#,
         );
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_deref.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_deref.rs
index b484635121eb..8f4405a8c869 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_deref.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_deref.rs
@@ -58,7 +58,8 @@ fn generate_record_deref(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<(
 
     let module = ctx.sema.to_def(&strukt)?.module(ctx.db());
     let trait_ = deref_type_to_generate.to_trait(&ctx.sema, module.krate())?;
-    let trait_path = module.find_use_path(ctx.db(), ModuleDef::Trait(trait_))?;
+    let trait_path =
+        module.find_use_path(ctx.db(), ModuleDef::Trait(trait_), ctx.config.prefer_no_std)?;
 
     let field_type = field.ty()?;
     let field_name = field.name()?;
@@ -98,7 +99,8 @@ fn generate_tuple_deref(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()
 
     let module = ctx.sema.to_def(&strukt)?.module(ctx.db());
     let trait_ = deref_type_to_generate.to_trait(&ctx.sema, module.krate())?;
-    let trait_path = module.find_use_path(ctx.db(), ModuleDef::Trait(trait_))?;
+    let trait_path =
+        module.find_use_path(ctx.db(), ModuleDef::Trait(trait_), ctx.config.prefer_no_std)?;
 
     let field_type = field.ty()?;
     let target = field.syntax().text_range();
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_new.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_new.rs
index 6c93875e9eb6..9cda74d9e0d3 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_new.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_new.rs
@@ -60,8 +60,11 @@ pub(crate) fn generate_new(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option
 
                 let item_in_ns = hir::ItemInNs::from(hir::ModuleDef::from(ty.as_adt()?));
 
-                let type_path = current_module
-                    .find_use_path(ctx.sema.db, item_for_path_search(ctx.sema.db, item_in_ns)?)?;
+                let type_path = current_module.find_use_path(
+                    ctx.sema.db,
+                    item_for_path_search(ctx.sema.db, item_in_ns)?,
+                    ctx.config.prefer_no_std,
+                )?;
 
                 let expr = use_trivial_constructor(
                     &ctx.sema.db,
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_call.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_call.rs
index 96890ad51a6f..9f51cdaf8b1e 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_call.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_call.rs
@@ -7,6 +7,7 @@ use ide_db::{
     imports::insert_use::remove_path_if_in_use_stmt,
     path_transform::PathTransform,
     search::{FileReference, SearchScope},
+    source_change::SourceChangeBuilder,
     syntax_helpers::{insert_whitespace_into_node::insert_ws_into, node_ext::expr_as_name_ref},
     RootDatabase,
 };
@@ -100,18 +101,7 @@ pub(crate) fn inline_into_callers(acc: &mut Assists, ctx: &AssistContext<'_>) ->
                 builder.edit_file(file_id);
                 let count = refs.len();
                 // The collects are required as we are otherwise iterating while mutating 🙅‍♀️🙅‍♂️
-                let (name_refs, name_refs_use): (Vec<_>, Vec<_>) = refs
-                    .into_iter()
-                    .filter_map(|file_ref| match file_ref.name {
-                        ast::NameLike::NameRef(name_ref) => Some(name_ref),
-                        _ => None,
-                    })
-                    .partition_map(|name_ref| {
-                        match name_ref.syntax().ancestors().find_map(ast::UseTree::cast) {
-                            Some(use_tree) => Either::Right(builder.make_mut(use_tree)),
-                            None => Either::Left(name_ref),
-                        }
-                    });
+                let (name_refs, name_refs_use) = split_refs_and_uses(builder, refs, Some);
                 let call_infos: Vec<_> = name_refs
                     .into_iter()
                     .filter_map(CallInfo::from_name_ref)
@@ -130,11 +120,7 @@ pub(crate) fn inline_into_callers(acc: &mut Assists, ctx: &AssistContext<'_>) ->
                     .count();
                 if replaced + name_refs_use.len() == count {
                     // we replaced all usages in this file, so we can remove the imports
-                    name_refs_use.into_iter().for_each(|use_tree| {
-                        if let Some(path) = use_tree.path() {
-                            remove_path_if_in_use_stmt(&path);
-                        }
-                    })
+                    name_refs_use.iter().for_each(remove_path_if_in_use_stmt);
                 } else {
                     remove_def = false;
                 }
@@ -153,6 +139,23 @@ pub(crate) fn inline_into_callers(acc: &mut Assists, ctx: &AssistContext<'_>) ->
     )
 }
 
+pub(super) fn split_refs_and_uses<T: ast::AstNode>(
+    builder: &mut SourceChangeBuilder,
+    iter: impl IntoIterator<Item = FileReference>,
+    mut map_ref: impl FnMut(ast::NameRef) -> Option<T>,
+) -> (Vec<T>, Vec<ast::Path>) {
+    iter.into_iter()
+        .filter_map(|file_ref| match file_ref.name {
+            ast::NameLike::NameRef(name_ref) => Some(name_ref),
+            _ => None,
+        })
+        .filter_map(|name_ref| match name_ref.syntax().ancestors().find_map(ast::UseTree::cast) {
+            Some(use_tree) => builder.make_mut(use_tree).path().map(Either::Right),
+            None => map_ref(name_ref).map(Either::Left),
+        })
+        .partition_map(|either| either)
+}
+
 // Assist: inline_call
 //
 // Inlines a function or method body creating a `let` statement per parameter unless the parameter
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_type_alias.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_type_alias.rs
index 9adf6381c1cb..353d467ed19f 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_type_alias.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/inline_type_alias.rs
@@ -3,7 +3,10 @@
 // - Remove unused aliases if there are no longer any users, see inline_call.rs.
 
 use hir::{HasSource, PathResolution};
-use ide_db::{defs::Definition, search::FileReference};
+use ide_db::{
+    defs::Definition, imports::insert_use::ast_to_remove_for_path_in_use_stmt,
+    search::FileReference,
+};
 use itertools::Itertools;
 use std::collections::HashMap;
 use syntax::{
@@ -16,6 +19,8 @@ use crate::{
     AssistId, AssistKind,
 };
 
+use super::inline_call::split_refs_and_uses;
+
 // Assist: inline_type_alias_uses
 //
 // Inline a type alias into all of its uses where possible.
@@ -31,7 +36,7 @@ use crate::{
 // ```
 // ->
 // ```
-// type A = i32;
+//
 // fn id(x: i32) -> i32 {
 //     x
 // };
@@ -58,20 +63,20 @@ pub(crate) fn inline_type_alias_uses(acc: &mut Assists, ctx: &AssistContext<'_>)
         name.syntax().text_range(),
         |builder| {
             let usages = usages.all();
+            let mut definition_deleted = false;
 
             let mut inline_refs_for_file = |file_id, refs: Vec<FileReference>| {
                 builder.edit_file(file_id);
 
-                let path_types: Vec<ast::PathType> = refs
-                    .into_iter()
-                    .filter_map(|file_ref| match file_ref.name {
-                        ast::NameLike::NameRef(path_type) => {
-                            path_type.syntax().ancestors().nth(3).and_then(ast::PathType::cast)
-                        }
-                        _ => None,
-                    })
-                    .collect();
+                let (path_types, path_type_uses) =
+                    split_refs_and_uses(builder, refs, |path_type| {
+                        path_type.syntax().ancestors().nth(3).and_then(ast::PathType::cast)
+                    });
 
+                path_type_uses
+                    .iter()
+                    .flat_map(ast_to_remove_for_path_in_use_stmt)
+                    .for_each(|x| builder.delete(x.syntax().text_range()));
                 for (target, replacement) in path_types.into_iter().filter_map(|path_type| {
                     let replacement = inline(&ast_alias, &path_type)?.to_text(&concrete_type);
                     let target = path_type.syntax().text_range();
@@ -79,11 +84,20 @@ pub(crate) fn inline_type_alias_uses(acc: &mut Assists, ctx: &AssistContext<'_>)
                 }) {
                     builder.replace(target, replacement);
                 }
+
+                if file_id == ctx.file_id() {
+                    builder.delete(ast_alias.syntax().text_range());
+                    definition_deleted = true;
+                }
             };
 
             for (file_id, refs) in usages.into_iter() {
                 inline_refs_for_file(file_id, refs);
             }
+            if !definition_deleted {
+                builder.edit_file(ctx.file_id());
+                builder.delete(ast_alias.syntax().text_range());
+            }
         },
     )
 }
@@ -929,7 +943,7 @@ fn foo() {
 }
 "#,
                 r#"
-type A = u32;
+
 
 fn foo() {
     let _: u32 = 3;
@@ -960,13 +974,13 @@ fn foo() {
                 r#"
 //- /lib.rs
 mod foo;
-type T<E> = Vec<E>;
+
 fn f() -> Vec<&str> {
     vec!["hello"]
 }
 
 //- /foo.rs
-use super::T;
+
 fn foo() {
     let _: Vec<i8> = Vec::new();
 }
@@ -990,7 +1004,12 @@ fn foo() {
 }
 "#,
                 r#"
-use super::I;
+//- /lib.rs
+mod foo;
+
+
+//- /foo.rs
+
 fn foo() {
     let _: i32 = 0;
 }
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/merge_imports.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/merge_imports.rs
index 7e102ceba891..2bdbec93b1f9 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/merge_imports.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/merge_imports.rs
@@ -1,6 +1,10 @@
 use either::Either;
 use ide_db::imports::merge_imports::{try_merge_imports, try_merge_trees, MergeBehavior};
-use syntax::{algo::neighbor, ast, match_ast, ted, AstNode, SyntaxElement, SyntaxNode};
+use syntax::{
+    algo::neighbor,
+    ast::{self, edit_in_place::Removable},
+    match_ast, ted, AstNode, SyntaxElement, SyntaxNode,
+};
 
 use crate::{
     assist_context::{AssistContext, Assists},
@@ -76,7 +80,7 @@ pub(crate) fn merge_imports(acc: &mut Assists, ctx: &AssistContext<'_>) -> Optio
                 .collect();
             for edit in edits_mut {
                 match edit {
-                    Remove(it) => it.as_ref().either(ast::Use::remove, ast::UseTree::remove),
+                    Remove(it) => it.as_ref().either(Removable::remove, Removable::remove),
                     Replace(old, new) => ted::replace(old, new),
                 }
             }
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_bounds.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_bounds.rs
index 176a3bf5803f..1dd376ac3fd5 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_bounds.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_bounds.rs
@@ -1,5 +1,9 @@
 use syntax::{
-    ast::{self, edit_in_place::GenericParamsOwnerEdit, make, AstNode, HasName, HasTypeBounds},
+    ast::{
+        self,
+        edit_in_place::{GenericParamsOwnerEdit, Removable},
+        make, AstNode, HasName, HasTypeBounds,
+    },
     match_ast,
 };
 
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_format_string_arg.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_format_string_arg.rs
new file mode 100644
index 000000000000..92b2fa79d717
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/move_format_string_arg.rs
@@ -0,0 +1,268 @@
+use crate::{AssistContext, Assists};
+use ide_db::{
+    assists::{AssistId, AssistKind},
+    syntax_helpers::{
+        format_string::is_format_string,
+        format_string_exprs::{parse_format_exprs, Arg},
+    },
+};
+use itertools::Itertools;
+use syntax::{ast, AstNode, AstToken, NodeOrToken, SyntaxKind::COMMA, TextRange};
+
+// Assist: move_format_string_arg
+//
+// Move an expression out of a format string.
+//
+// ```
+// macro_rules! format_args {
+//     ($lit:literal $(tt:tt)*) => { 0 },
+// }
+// macro_rules! print {
+//     ($($arg:tt)*) => (std::io::_print(format_args!($($arg)*)));
+// }
+//
+// fn main() {
+//     print!("{x + 1}$0");
+// }
+// ```
+// ->
+// ```
+// macro_rules! format_args {
+//     ($lit:literal $(tt:tt)*) => { 0 },
+// }
+// macro_rules! print {
+//     ($($arg:tt)*) => (std::io::_print(format_args!($($arg)*)));
+// }
+//
+// fn main() {
+//     print!("{}"$0, x + 1);
+// }
+// ```
+
+pub(crate) fn move_format_string_arg(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+    let fmt_string = ctx.find_token_at_offset::<ast::String>()?;
+    let tt = fmt_string.syntax().parent().and_then(ast::TokenTree::cast)?;
+
+    let expanded_t = ast::String::cast(
+        ctx.sema.descend_into_macros_with_kind_preference(fmt_string.syntax().clone()),
+    )?;
+    if !is_format_string(&expanded_t) {
+        return None;
+    }
+
+    let (new_fmt, extracted_args) = parse_format_exprs(fmt_string.text()).ok()?;
+    if extracted_args.is_empty() {
+        return None;
+    }
+
+    acc.add(
+        AssistId(
+            "move_format_string_arg",
+            // if there aren't any expressions, then make the assist a RefactorExtract
+            if extracted_args.iter().filter(|f| matches!(f, Arg::Expr(_))).count() == 0 {
+                AssistKind::RefactorExtract
+            } else {
+                AssistKind::QuickFix
+            },
+        ),
+        "Extract format args",
+        tt.syntax().text_range(),
+        |edit| {
+            let fmt_range = fmt_string.syntax().text_range();
+
+            // Replace old format string with new format string whose arguments have been extracted
+            edit.replace(fmt_range, new_fmt);
+
+            // Insert cursor at end of format string
+            edit.insert(fmt_range.end(), "$0");
+
+            // Extract existing arguments in macro
+            let tokens =
+                tt.token_trees_and_tokens().filter_map(NodeOrToken::into_token).collect_vec();
+
+            let mut existing_args: Vec<String> = vec![];
+
+            let mut current_arg = String::new();
+            if let [_opening_bracket, format_string, _args_start_comma, tokens @ .., end_bracket] =
+                tokens.as_slice()
+            {
+                for t in tokens {
+                    if t.kind() == COMMA {
+                        existing_args.push(current_arg.trim().into());
+                        current_arg.clear();
+                    } else {
+                        current_arg.push_str(t.text());
+                    }
+                }
+                existing_args.push(current_arg.trim().into());
+
+                // delete everything after the format string till end bracket
+                // we're going to insert the new arguments later
+                edit.delete(TextRange::new(
+                    format_string.text_range().end(),
+                    end_bracket.text_range().start(),
+                ));
+            }
+
+            // Start building the new args
+            let mut existing_args = existing_args.into_iter();
+            let mut args = String::new();
+
+            let mut placeholder_idx = 1;
+
+            for extracted_args in extracted_args {
+                // remove expr from format string
+                args.push_str(", ");
+
+                match extracted_args {
+                    Arg::Ident(s) | Arg::Expr(s) => {
+                        // insert arg
+                        args.push_str(&s);
+                    }
+                    Arg::Placeholder => {
+                        // try matching with existing argument
+                        match existing_args.next() {
+                            Some(ea) => {
+                                args.push_str(&ea);
+                            }
+                            None => {
+                                // insert placeholder
+                                args.push_str(&format!("${placeholder_idx}"));
+                                placeholder_idx += 1;
+                            }
+                        }
+                    }
+                }
+            }
+
+            // Insert new args
+            edit.insert(fmt_range.end(), args);
+        },
+    );
+
+    Some(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tests::check_assist;
+
+    const MACRO_DECL: &'static str = r#"
+macro_rules! format_args {
+    ($lit:literal $(tt:tt)*) => { 0 },
+}
+macro_rules! print {
+    ($($arg:tt)*) => (std::io::_print(format_args!($($arg)*)));
+}
+"#;
+
+    fn add_macro_decl(s: &'static str) -> String {
+        MACRO_DECL.to_string() + s
+    }
+
+    #[test]
+    fn multiple_middle_arg() {
+        check_assist(
+            move_format_string_arg,
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {x + 1:b} {}$0", y + 2, 2);
+}
+"#,
+            ),
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {:b} {}"$0, y + 2, x + 1, 2);
+}
+"#,
+            ),
+        );
+    }
+
+    #[test]
+    fn single_arg() {
+        check_assist(
+            move_format_string_arg,
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{obj.value:b}$0",);
+}
+"#,
+            ),
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{:b}"$0, obj.value);
+}
+"#,
+            ),
+        );
+    }
+
+    #[test]
+    fn multiple_middle_placeholders_arg() {
+        check_assist(
+            move_format_string_arg,
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {x + 1:b} {} {}$0", y + 2, 2);
+}
+"#,
+            ),
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {:b} {} {}"$0, y + 2, x + 1, 2, $1);
+}
+"#,
+            ),
+        );
+    }
+
+    #[test]
+    fn multiple_trailing_args() {
+        check_assist(
+            move_format_string_arg,
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {x + 1:b} {Struct(1, 2)}$0", 1);
+}
+"#,
+            ),
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {:b} {}"$0, 1, x + 1, Struct(1, 2));
+}
+"#,
+            ),
+        );
+    }
+
+    #[test]
+    fn improper_commas() {
+        check_assist(
+            move_format_string_arg,
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {x + 1:b} {Struct(1, 2)}$0", 1,);
+}
+"#,
+            ),
+            &add_macro_decl(
+                r#"
+fn main() {
+    print!("{} {:b} {}"$0, 1, x + 1, Struct(1, 2));
+}
+"#,
+            ),
+        );
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_method_call.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_method_call.rs
index 121f8b4a1368..e57d1d065d62 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_method_call.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_method_call.rs
@@ -44,8 +44,11 @@ pub(crate) fn qualify_method_call(acc: &mut Assists, ctx: &AssistContext<'_>) ->
     let current_module = ctx.sema.scope(call.syntax())?.module();
     let target_module_def = ModuleDef::from(resolved_call);
     let item_in_ns = ItemInNs::from(target_module_def);
-    let receiver_path = current_module
-        .find_use_path(ctx.sema.db, item_for_path_search(ctx.sema.db, item_in_ns)?)?;
+    let receiver_path = current_module.find_use_path(
+        ctx.sema.db,
+        item_for_path_search(ctx.sema.db, item_in_ns)?,
+        ctx.config.prefer_no_std,
+    )?;
 
     let qualify_candidate = QualifyCandidate::ImplMethod(ctx.sema.db, call, resolved_call);
 
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_path.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_path.rs
index 0c2e9da38639..4b2af550bc5e 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_path.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/qualify_path.rs
@@ -37,7 +37,8 @@ use crate::{
 // ```
 pub(crate) fn qualify_path(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
     let (import_assets, syntax_under_caret) = find_importable_node(ctx)?;
-    let mut proposed_imports = import_assets.search_for_relative_paths(&ctx.sema);
+    let mut proposed_imports =
+        import_assets.search_for_relative_paths(&ctx.sema, ctx.config.prefer_no_std);
     if proposed_imports.is_empty() {
         return None;
     }
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
index d139f78a6f36..9fd5e1886d20 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -85,7 +85,7 @@ pub(crate) fn replace_derive_with_manual_impl(
     })
     .flat_map(|trait_| {
         current_module
-            .find_use_path(ctx.sema.db, hir::ModuleDef::Trait(trait_))
+            .find_use_path(ctx.sema.db, hir::ModuleDef::Trait(trait_), ctx.config.prefer_no_std)
             .as_ref()
             .map(mod_path_to_ast)
             .zip(Some(trait_))
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_or_with_or_else.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_or_with_or_else.rs
new file mode 100644
index 000000000000..7d91be621013
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_or_with_or_else.rs
@@ -0,0 +1,364 @@
+use ide_db::{
+    assists::{AssistId, AssistKind},
+    famous_defs::FamousDefs,
+};
+use syntax::{
+    ast::{self, make, Expr, HasArgList},
+    AstNode,
+};
+
+use crate::{AssistContext, Assists};
+
+// Assist: replace_or_with_or_else
+//
+// Replace `unwrap_or` with `unwrap_or_else` and `ok_or` with `ok_or_else`.
+//
+// ```
+// # //- minicore:option
+// fn foo() {
+//     let a = Some(1);
+//     a.unwra$0p_or(2);
+// }
+// ```
+// ->
+// ```
+// fn foo() {
+//     let a = Some(1);
+//     a.unwrap_or_else(|| 2);
+// }
+// ```
+pub(crate) fn replace_or_with_or_else(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+    let call: ast::MethodCallExpr = ctx.find_node_at_offset()?;
+
+    let kind = is_option_or_result(call.receiver()?, ctx)?;
+
+    let (name, arg_list) = (call.name_ref()?, call.arg_list()?);
+
+    let mut map_or = false;
+
+    let replace = match &*name.text() {
+        "unwrap_or" => "unwrap_or_else".to_string(),
+        "or" => "or_else".to_string(),
+        "ok_or" if kind == Kind::Option => "ok_or_else".to_string(),
+        "map_or" => {
+            map_or = true;
+            "map_or_else".to_string()
+        }
+        _ => return None,
+    };
+
+    let arg = match arg_list.args().collect::<Vec<_>>().as_slice() {
+        [] => make::arg_list(Vec::new()),
+        [first] => {
+            let param = into_closure(first);
+            make::arg_list(vec![param])
+        }
+        [first, second] if map_or => {
+            let param = into_closure(first);
+            make::arg_list(vec![param, second.clone()])
+        }
+        _ => return None,
+    };
+
+    acc.add(
+        AssistId("replace_or_with_or_else", AssistKind::RefactorRewrite),
+        format!("Replace {} with {}", name.text(), replace),
+        call.syntax().text_range(),
+        |builder| {
+            builder.replace(name.syntax().text_range(), replace);
+            builder.replace_ast(arg_list, arg)
+        },
+    )
+}
+
+fn into_closure(param: &Expr) -> Expr {
+    (|| {
+        if let ast::Expr::CallExpr(call) = param {
+            if call.arg_list()?.args().count() == 0 {
+                Some(call.expr()?.clone())
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    })()
+    .unwrap_or_else(|| make::expr_closure(None, param.clone()))
+}
+
+// Assist: replace_or_else_with_or
+//
+// Replace `unwrap_or_else` with `unwrap_or` and `ok_or_else` with `ok_or`.
+//
+// ```
+// # //- minicore:option
+// fn foo() {
+//     let a = Some(1);
+//     a.unwra$0p_or_else(|| 2);
+// }
+// ```
+// ->
+// ```
+// fn foo() {
+//     let a = Some(1);
+//     a.unwrap_or(2);
+// }
+// ```
+pub(crate) fn replace_or_else_with_or(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+    let call: ast::MethodCallExpr = ctx.find_node_at_offset()?;
+
+    let kind = is_option_or_result(call.receiver()?, ctx)?;
+
+    let (name, arg_list) = (call.name_ref()?, call.arg_list()?);
+
+    let mut map_or = false;
+    let replace = match &*name.text() {
+        "unwrap_or_else" => "unwrap_or".to_string(),
+        "or_else" => "or".to_string(),
+        "ok_or_else" if kind == Kind::Option => "ok_or".to_string(),
+        "map_or_else" => {
+            map_or = true;
+            "map_or".to_string()
+        }
+        _ => return None,
+    };
+
+    let arg = match arg_list.args().collect::<Vec<_>>().as_slice() {
+        [] => make::arg_list(Vec::new()),
+        [first] => {
+            let param = into_call(first);
+            make::arg_list(vec![param])
+        }
+        [first, second] if map_or => {
+            let param = into_call(first);
+            make::arg_list(vec![param, second.clone()])
+        }
+        _ => return None,
+    };
+
+    acc.add(
+        AssistId("replace_or_else_with_or", AssistKind::RefactorRewrite),
+        format!("Replace {} with {}", name.text(), replace),
+        call.syntax().text_range(),
+        |builder| {
+            builder.replace(name.syntax().text_range(), replace);
+            builder.replace_ast(arg_list, arg)
+        },
+    )
+}
+
+fn into_call(param: &Expr) -> Expr {
+    (|| {
+        if let ast::Expr::ClosureExpr(closure) = param {
+            if closure.param_list()?.params().count() == 0 {
+                Some(closure.body()?.clone())
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    })()
+    .unwrap_or_else(|| make::expr_call(param.clone(), make::arg_list(Vec::new())))
+}
+
+#[derive(PartialEq, Eq)]
+enum Kind {
+    Option,
+    Result,
+}
+
+fn is_option_or_result(receiver: Expr, ctx: &AssistContext<'_>) -> Option<Kind> {
+    let ty = ctx.sema.type_of_expr(&receiver)?.adjusted().as_adt()?.as_enum()?;
+    let option_enum =
+        FamousDefs(&ctx.sema, ctx.sema.scope(receiver.syntax())?.krate()).core_option_Option();
+
+    if let Some(option_enum) = option_enum {
+        if ty == option_enum {
+            return Some(Kind::Option);
+        }
+    }
+
+    let result_enum =
+        FamousDefs(&ctx.sema, ctx.sema.scope(receiver.syntax())?.krate()).core_result_Result();
+
+    if let Some(result_enum) = result_enum {
+        if ty == result_enum {
+            return Some(Kind::Result);
+        }
+    }
+
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn replace_or_with_or_else_simple() {
+        check_assist(
+            replace_or_with_or_else,
+            r#"
+//- minicore: option
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_$0or(2);
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_or_else(|| 2);
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_with_or_else_call() {
+        check_assist(
+            replace_or_with_or_else,
+            r#"
+//- minicore: option
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_$0or(x());
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_or_else(x);
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_with_or_else_block() {
+        check_assist(
+            replace_or_with_or_else,
+            r#"
+//- minicore: option
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_$0or({
+        let mut x = bar();
+        for i in 0..10 {
+            x += i;
+        }
+        x
+    });
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_or_else(|| {
+        let mut x = bar();
+        for i in 0..10 {
+            x += i;
+        }
+        x
+    });
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_else_with_or_simple() {
+        check_assist(
+            replace_or_else_with_or,
+            r#"
+//- minicore: option
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_$0or_else(|| 2);
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_or(2);
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_else_with_or_call() {
+        check_assist(
+            replace_or_else_with_or,
+            r#"
+//- minicore: option
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_$0or_else(x);
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Some(1);
+    return foo.unwrap_or(x());
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_else_with_or_result() {
+        check_assist(
+            replace_or_else_with_or,
+            r#"
+//- minicore: result
+fn foo() {
+    let foo = Ok(1);
+    return foo.unwrap_$0or_else(x);
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Ok(1);
+    return foo.unwrap_or(x());
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_else_with_or_map() {
+        check_assist(
+            replace_or_else_with_or,
+            r#"
+//- minicore: result
+fn foo() {
+    let foo = Ok("foo");
+    return foo.map$0_or_else(|| 42, |v| v.len());
+}
+"#,
+            r#"
+fn foo() {
+    let foo = Ok("foo");
+    return foo.map_or(42, |v| v.len());
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_or_else_with_or_not_applicable() {
+        check_assist_not_applicable(
+            replace_or_else_with_or,
+            r#"
+fn foo() {
+    let foo = Ok(1);
+    return foo.unwrap_$0or_else(x);
+}
+"#,
+        )
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_qualified_name_with_use.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_qualified_name_with_use.rs
index 2419fa11c155..dbbc56958f1e 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_qualified_name_with_use.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_qualified_name_with_use.rs
@@ -67,6 +67,7 @@ pub(crate) fn replace_qualified_name_with_use(
                 ctx.sema.db,
                 module,
                 ctx.config.insert_use.prefix_kind,
+                ctx.config.prefer_no_std,
             )
         })
         .flatten();
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_turbofish_with_explicit_type.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_turbofish_with_explicit_type.rs
index 5242f3b5100c..521447c26dfb 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_turbofish_with_explicit_type.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/replace_turbofish_with_explicit_type.rs
@@ -1,5 +1,6 @@
+use hir::HirDisplay;
 use syntax::{
-    ast::{Expr, GenericArg},
+    ast::{Expr, GenericArg, GenericArgList},
     ast::{LetStmt, Type::InferType},
     AstNode, TextRange,
 };
@@ -34,21 +35,7 @@ pub(crate) fn replace_turbofish_with_explicit_type(
 
     let initializer = let_stmt.initializer()?;
 
-    let generic_args = match &initializer {
-        Expr::MethodCallExpr(ce) => ce.generic_arg_list()?,
-        Expr::CallExpr(ce) => {
-            if let Expr::PathExpr(pe) = ce.expr()? {
-                pe.path()?.segment()?.generic_arg_list()?
-            } else {
-                cov_mark::hit!(not_applicable_if_non_path_function_call);
-                return None;
-            }
-        }
-        _ => {
-            cov_mark::hit!(not_applicable_if_non_function_call_initializer);
-            return None;
-        }
-    };
+    let generic_args = generic_arg_list(&initializer)?;
 
     // Find range of ::<_>
     let colon2 = generic_args.coloncolon_token()?;
@@ -65,7 +52,16 @@ pub(crate) fn replace_turbofish_with_explicit_type(
 
     // An improvement would be to check that this is correctly part of the return value of the
     // function call, or sub in the actual return type.
-    let turbofish_type = &turbofish_args[0];
+    let returned_type = match ctx.sema.type_of_expr(&initializer) {
+        Some(returned_type) if !returned_type.original.contains_unknown() => {
+            let module = ctx.sema.scope(let_stmt.syntax())?.module();
+            returned_type.original.display_source_code(ctx.db(), module.into()).ok()?
+        }
+        _ => {
+            cov_mark::hit!(fallback_to_turbofish_type_if_type_info_not_available);
+            turbofish_args[0].to_string()
+        }
+    };
 
     let initializer_start = initializer.syntax().text_range().start();
     if ctx.offset() > turbofish_range.end() || ctx.offset() < initializer_start {
@@ -83,7 +79,7 @@ pub(crate) fn replace_turbofish_with_explicit_type(
             "Replace turbofish with explicit type",
             TextRange::new(initializer_start, turbofish_range.end()),
             |builder| {
-                builder.insert(ident_range.end(), format!(": {}", turbofish_type));
+                builder.insert(ident_range.end(), format!(": {}", returned_type));
                 builder.delete(turbofish_range);
             },
         );
@@ -98,7 +94,7 @@ pub(crate) fn replace_turbofish_with_explicit_type(
             "Replace `_` with turbofish type",
             turbofish_range,
             |builder| {
-                builder.replace(underscore_range, turbofish_type.to_string());
+                builder.replace(underscore_range, returned_type);
                 builder.delete(turbofish_range);
             },
         );
@@ -107,6 +103,26 @@ pub(crate) fn replace_turbofish_with_explicit_type(
     None
 }
 
+fn generic_arg_list(expr: &Expr) -> Option<GenericArgList> {
+    match expr {
+        Expr::MethodCallExpr(expr) => expr.generic_arg_list(),
+        Expr::CallExpr(expr) => {
+            if let Expr::PathExpr(pe) = expr.expr()? {
+                pe.path()?.segment()?.generic_arg_list()
+            } else {
+                cov_mark::hit!(not_applicable_if_non_path_function_call);
+                return None;
+            }
+        }
+        Expr::AwaitExpr(expr) => generic_arg_list(&expr.expr()?),
+        Expr::TryExpr(expr) => generic_arg_list(&expr.expr()?),
+        _ => {
+            cov_mark::hit!(not_applicable_if_non_function_call_initializer);
+            None
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -115,6 +131,7 @@ mod tests {
 
     #[test]
     fn replaces_turbofish_for_vec_string() {
+        cov_mark::check!(fallback_to_turbofish_type_if_type_info_not_available);
         check_assist(
             replace_turbofish_with_explicit_type,
             r#"
@@ -135,6 +152,7 @@ fn main() {
     #[test]
     fn replaces_method_calls() {
         // foo.make() is a method call which uses a different expr in the let initializer
+        cov_mark::check!(fallback_to_turbofish_type_if_type_info_not_available);
         check_assist(
             replace_turbofish_with_explicit_type,
             r#"
@@ -237,6 +255,110 @@ fn make<T>() -> T {}
 fn main() {
     let a = make$0::<Vec<String>, i32>();
 }
+"#,
+        );
+    }
+
+    #[test]
+    fn replaces_turbofish_for_known_type() {
+        check_assist(
+            replace_turbofish_with_explicit_type,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    let a = make$0::<i32>();
+}
+"#,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    let a: i32 = make();
+}
+"#,
+        );
+        check_assist(
+            replace_turbofish_with_explicit_type,
+            r#"
+//- minicore: option
+fn make<T>() -> T {}
+fn main() {
+    let a = make$0::<Option<bool>>();
+}
+"#,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    let a: Option<bool> = make();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn replaces_turbofish_not_same_type() {
+        check_assist(
+            replace_turbofish_with_explicit_type,
+            r#"
+//- minicore: option
+fn make<T>() -> Option<T> {}
+fn main() {
+    let a = make$0::<u128>();
+}
+"#,
+            r#"
+fn make<T>() -> Option<T> {}
+fn main() {
+    let a: Option<u128> = make();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn replaces_turbofish_for_type_with_defaulted_generic_param() {
+        check_assist(
+            replace_turbofish_with_explicit_type,
+            r#"
+struct HasDefault<T, U = i32>(T, U);
+fn make<T>() -> HasDefault<T> {}
+fn main() {
+    let a = make$0::<bool>();
+}
+"#,
+            r#"
+struct HasDefault<T, U = i32>(T, U);
+fn make<T>() -> HasDefault<T> {}
+fn main() {
+    let a: HasDefault<bool> = make();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn replaces_turbofish_try_await() {
+        check_assist(
+            replace_turbofish_with_explicit_type,
+            r#"
+//- minicore: option, future
+struct Fut<T>(T);
+impl<T> core::future::Future for Fut<T> {
+    type Output = Option<T>;
+}
+fn make<T>() -> Fut<T> {}
+fn main() {
+    let a = make$0::<bool>().await?;
+}
+"#,
+            r#"
+struct Fut<T>(T);
+impl<T> core::future::Future for Fut<T> {
+    type Output = Option<T>;
+}
+fn make<T>() -> Fut<T> {}
+fn main() {
+    let a: bool = make().await?;
+}
 "#,
         );
     }
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_match_arm.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_match_arm.rs
new file mode 100644
index 000000000000..9565f0ee6f26
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_match_arm.rs
@@ -0,0 +1,293 @@
+use syntax::{
+    algo::neighbor,
+    ast::{self, edit::IndentLevel, make, AstNode},
+    ted::{self, Position},
+    Direction, SyntaxKind, T,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: unmerge_match_arm
+//
+// Splits the current match with a `|` pattern into two arms with identical bodies.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move(..) $0| Action::Stop => foo(),
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move(..) => foo(),
+//         Action::Stop => foo(),
+//     }
+// }
+// ```
+pub(crate) fn unmerge_match_arm(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+    let pipe_token = ctx.find_token_syntax_at_offset(T![|])?;
+    let or_pat = ast::OrPat::cast(pipe_token.parent()?)?.clone_for_update();
+    let match_arm = ast::MatchArm::cast(or_pat.syntax().parent()?)?;
+    let match_arm_body = match_arm.expr()?;
+
+    // We don't need to check for leading pipe because it is directly under `MatchArm`
+    // without `OrPat`.
+
+    let new_parent = match_arm.syntax().parent()?;
+    let old_parent_range = new_parent.text_range();
+
+    acc.add(
+        AssistId("unmerge_match_arm", AssistKind::RefactorRewrite),
+        "Unmerge match arm",
+        pipe_token.text_range(),
+        |edit| {
+            let pats_after = pipe_token
+                .siblings_with_tokens(Direction::Next)
+                .filter_map(|it| ast::Pat::cast(it.into_node()?));
+            // FIXME: We should add a leading pipe if the original arm has one.
+            let new_match_arm = make::match_arm(
+                pats_after,
+                match_arm.guard().and_then(|guard| guard.condition()),
+                match_arm_body,
+            )
+            .clone_for_update();
+
+            let mut pipe_index = pipe_token.index();
+            if pipe_token
+                .prev_sibling_or_token()
+                .map_or(false, |it| it.kind() == SyntaxKind::WHITESPACE)
+            {
+                pipe_index -= 1;
+            }
+            or_pat.syntax().splice_children(
+                pipe_index..or_pat.syntax().children_with_tokens().count(),
+                Vec::new(),
+            );
+
+            let mut insert_after_old_arm = Vec::new();
+
+            // A comma can be:
+            //  - After the arm. In this case we always want to insert a comma after the newly
+            //    inserted arm.
+            //  - Missing after the arm, with no arms after. In this case we want to insert a
+            //    comma before the newly inserted arm. It can not be necessary if there arm
+            //    body is a block, but we don't bother to check that.
+            //  - Missing after the arm with arms after, if the arm body is a block. In this case
+            //    we don't want to insert a comma at all.
+            let has_comma_after =
+                std::iter::successors(match_arm.syntax().last_child_or_token(), |it| {
+                    it.prev_sibling_or_token()
+                })
+                .map(|it| it.kind())
+                .skip_while(|it| it.is_trivia())
+                .next()
+                    == Some(T![,]);
+            let has_arms_after = neighbor(&match_arm, Direction::Next).is_some();
+            if !has_comma_after && !has_arms_after {
+                insert_after_old_arm.push(make::token(T![,]).into());
+            }
+
+            let indent = IndentLevel::from_node(match_arm.syntax());
+            insert_after_old_arm.push(make::tokens::whitespace(&format!("\n{indent}")).into());
+
+            insert_after_old_arm.push(new_match_arm.syntax().clone().into());
+
+            ted::insert_all_raw(Position::after(match_arm.syntax()), insert_after_old_arm);
+
+            if has_comma_after {
+                ted::insert_raw(
+                    Position::last_child_of(new_match_arm.syntax()),
+                    make::token(T![,]),
+                );
+            }
+
+            edit.replace(old_parent_range, new_parent.to_string());
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn unmerge_match_arm_single_pipe() {
+        check_assist(
+            unmerge_match_arm,
+            r#"
+#[derive(Debug)]
+enum X { A, B, C }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A $0| X::B => { 1i32 }
+        X::C => { 2i32 }
+    };
+}
+"#,
+            r#"
+#[derive(Debug)]
+enum X { A, B, C }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A => { 1i32 }
+        X::B => { 1i32 }
+        X::C => { 2i32 }
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unmerge_match_arm_guard() {
+        check_assist(
+            unmerge_match_arm,
+            r#"
+#[derive(Debug)]
+enum X { A, B, C }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A $0| X::B if true => { 1i32 }
+        _ => { 2i32 }
+    };
+}
+"#,
+            r#"
+#[derive(Debug)]
+enum X { A, B, C }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A if true => { 1i32 }
+        X::B if true => { 1i32 }
+        _ => { 2i32 }
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unmerge_match_arm_leading_pipe() {
+        check_assist_not_applicable(
+            unmerge_match_arm,
+            r#"
+
+fn main() {
+    let y = match 0 {
+        |$0 0 => { 1i32 }
+        1 => { 2i32 }
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unmerge_match_arm_multiple_pipes() {
+        check_assist(
+            unmerge_match_arm,
+            r#"
+#[derive(Debug)]
+enum X { A, B, C, D, E }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A | X::B |$0 X::C | X::D => 1i32,
+        X::E => 2i32,
+    };
+}
+"#,
+            r#"
+#[derive(Debug)]
+enum X { A, B, C, D, E }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A | X::B => 1i32,
+        X::C | X::D => 1i32,
+        X::E => 2i32,
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unmerge_match_arm_inserts_comma_if_required() {
+        check_assist(
+            unmerge_match_arm,
+            r#"
+#[derive(Debug)]
+enum X { A, B }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A $0| X::B => 1i32
+    };
+}
+"#,
+            r#"
+#[derive(Debug)]
+enum X { A, B }
+
+fn main() {
+    let x = X::A;
+    let y = match x {
+        X::A => 1i32,
+        X::B => 1i32
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unmerge_match_arm_inserts_comma_if_had_after() {
+        check_assist(
+            unmerge_match_arm,
+            r#"
+#[derive(Debug)]
+enum X { A, B }
+
+fn main() {
+    let x = X::A;
+    match x {
+        X::A $0| X::B => {},
+    }
+}
+"#,
+            r#"
+#[derive(Debug)]
+enum X { A, B }
+
+fn main() {
+    let x = X::A;
+    match x {
+        X::A => {},
+        X::B => {},
+    }
+}
+"#,
+        );
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_use.rs b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_use.rs
index 3ce028e93065..dac216b69b72 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_use.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/handlers/unmerge_use.rs
@@ -1,5 +1,5 @@
 use syntax::{
-    ast::{self, make, HasVisibility},
+    ast::{self, edit_in_place::Removable, make, HasVisibility},
     ted::{self, Position},
     AstNode, SyntaxKind,
 };
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs b/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs
index 7fb35143fa2f..812d22efbd79 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs
@@ -122,6 +122,7 @@ mod handlers {
     mod convert_let_else_to_match;
     mod convert_tuple_struct_to_named_struct;
     mod convert_to_guarded_return;
+    mod convert_two_arm_bool_match_to_matches_macro;
     mod convert_while_to_loop;
     mod destructure_tuple_binding;
     mod expand_glob_import;
@@ -135,6 +136,7 @@ mod handlers {
     mod flip_binexpr;
     mod flip_comma;
     mod flip_trait_bound;
+    mod move_format_string_arg;
     mod generate_constant;
     mod generate_default_from_enum_variant;
     mod generate_default_from_new;
@@ -179,12 +181,14 @@ mod handlers {
     mod replace_try_expr_with_match;
     mod replace_derive_with_manual_impl;
     mod replace_if_let_with_match;
+    mod replace_or_with_or_else;
     mod introduce_named_generic;
     mod replace_let_with_if_let;
     mod replace_qualified_name_with_use;
     mod replace_string_with_char;
     mod replace_turbofish_with_explicit_type;
     mod split_import;
+    mod unmerge_match_arm;
     mod sort_items;
     mod toggle_ignore;
     mod unmerge_use;
@@ -215,6 +219,7 @@ mod handlers {
             convert_let_else_to_match::convert_let_else_to_match,
             convert_to_guarded_return::convert_to_guarded_return,
             convert_tuple_struct_to_named_struct::convert_tuple_struct_to_named_struct,
+            convert_two_arm_bool_match_to_matches_macro::convert_two_arm_bool_match_to_matches_macro,
             convert_while_to_loop::convert_while_to_loop,
             destructure_tuple_binding::destructure_tuple_binding,
             expand_glob_import::expand_glob_import,
@@ -250,6 +255,7 @@ mod handlers {
             merge_imports::merge_imports,
             merge_match_arms::merge_match_arms,
             move_bounds::move_bounds_to_where_clause,
+            move_format_string_arg::move_format_string_arg,
             move_guard::move_arm_cond_to_match_guard,
             move_guard::move_guard_to_arm_body,
             move_module_to_file::move_module_to_file,
@@ -273,11 +279,14 @@ mod handlers {
             replace_if_let_with_match::replace_if_let_with_match,
             replace_if_let_with_match::replace_match_with_if_let,
             replace_let_with_if_let::replace_let_with_if_let,
+            replace_or_with_or_else::replace_or_else_with_or,
+            replace_or_with_or_else::replace_or_with_or_else,
             replace_turbofish_with_explicit_type::replace_turbofish_with_explicit_type,
             replace_qualified_name_with_use::replace_qualified_name_with_use,
             sort_items::sort_items,
             split_import::split_import,
             toggle_ignore::toggle_ignore,
+            unmerge_match_arm::unmerge_match_arm,
             unmerge_use::unmerge_use,
             unnecessary_async::unnecessary_async,
             unwrap_block::unwrap_block,
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/tests.rs b/src/tools/rust-analyzer/crates/ide-assists/src/tests.rs
index 9cd66c6b3b07..258144bae3d0 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/tests.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/tests.rs
@@ -29,6 +29,7 @@ pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
         group: true,
         skip_glob_imports: true,
     },
+    prefer_no_std: false,
 };
 
 pub(crate) fn with_single_file(text: &str) -> (RootDatabase, FileId) {
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/tests/generated.rs b/src/tools/rust-analyzer/crates/ide-assists/src/tests/generated.rs
index 22319f36134f..3a696635afd2 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/tests/generated.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/tests/generated.rs
@@ -472,6 +472,26 @@ impl Point {
     )
 }
 
+#[test]
+fn doctest_convert_two_arm_bool_match_to_matches_macro() {
+    check_doc_test(
+        "convert_two_arm_bool_match_to_matches_macro",
+        r#####"
+fn main() {
+    match scrutinee$0 {
+        Some(val) if val.cond() => true,
+        _ => false,
+    }
+}
+"#####,
+        r#####"
+fn main() {
+    matches!(scrutinee, Some(val) if val.cond())
+}
+"#####,
+    )
+}
+
 #[test]
 fn doctest_convert_while_to_loop() {
     check_doc_test(
@@ -1370,7 +1390,7 @@ fn foo() {
 }
 "#####,
         r#####"
-type A = i32;
+
 fn id(x: i32) -> i32 {
     x
 };
@@ -1571,6 +1591,37 @@ fn apply<T, U, F>(f: F, x: T) -> U where F: FnOnce(T) -> U {
     )
 }
 
+#[test]
+fn doctest_move_format_string_arg() {
+    check_doc_test(
+        "move_format_string_arg",
+        r#####"
+macro_rules! format_args {
+    ($lit:literal $(tt:tt)*) => { 0 },
+}
+macro_rules! print {
+    ($($arg:tt)*) => (std::io::_print(format_args!($($arg)*)));
+}
+
+fn main() {
+    print!("{x + 1}$0");
+}
+"#####,
+        r#####"
+macro_rules! format_args {
+    ($lit:literal $(tt:tt)*) => { 0 },
+}
+macro_rules! print {
+    ($($arg:tt)*) => (std::io::_print(format_args!($($arg)*)));
+}
+
+fn main() {
+    print!("{}"$0, x + 1);
+}
+"#####,
+    )
+}
+
 #[test]
 fn doctest_move_from_mod_rs() {
     check_doc_test(
@@ -2009,6 +2060,46 @@ fn handle(action: Action) {
     )
 }
 
+#[test]
+fn doctest_replace_or_else_with_or() {
+    check_doc_test(
+        "replace_or_else_with_or",
+        r#####"
+//- minicore:option
+fn foo() {
+    let a = Some(1);
+    a.unwra$0p_or_else(|| 2);
+}
+"#####,
+        r#####"
+fn foo() {
+    let a = Some(1);
+    a.unwrap_or(2);
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_or_with_or_else() {
+    check_doc_test(
+        "replace_or_with_or_else",
+        r#####"
+//- minicore:option
+fn foo() {
+    let a = Some(1);
+    a.unwra$0p_or(2);
+}
+"#####,
+        r#####"
+fn foo() {
+    let a = Some(1);
+    a.unwrap_or_else(|| 2);
+}
+"#####,
+    )
+}
+
 #[test]
 fn doctest_replace_qualified_name_with_use() {
     check_doc_test(
@@ -2207,6 +2298,32 @@ fn arithmetics {
     )
 }
 
+#[test]
+fn doctest_unmerge_match_arm() {
+    check_doc_test(
+        "unmerge_match_arm",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move(..) $0| Action::Stop => foo(),
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move(..) => foo(),
+        Action::Stop => foo(),
+    }
+}
+"#####,
+    )
+}
+
 #[test]
 fn doctest_unmerge_use() {
     check_doc_test(
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs b/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs
index 103e3259fa2e..4ab6e2627fa7 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/utils.rs
@@ -12,7 +12,7 @@ use syntax::{
     ast::{
         self,
         edit::{self, AstNodeEdit},
-        edit_in_place::AttrsOwnerEdit,
+        edit_in_place::{AttrsOwnerEdit, Removable},
         make, HasArgList, HasAttrs, HasGenericParams, HasName, HasTypeBounds, Whitespace,
     },
     ted, AstNode, AstToken, Direction, SmolStr, SourceFile,
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions.rs
index 55c3e28392a4..97b90c62dd77 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions.rs
@@ -551,7 +551,11 @@ fn enum_variants_with_paths(
     }
 
     for variant in variants {
-        if let Some(path) = ctx.module.find_use_path(ctx.db, hir::ModuleDef::from(variant)) {
+        if let Some(path) = ctx.module.find_use_path(
+            ctx.db,
+            hir::ModuleDef::from(variant),
+            ctx.config.prefer_no_std,
+        ) {
             // Variants with trivial paths are already added by the existing completion logic,
             // so we should avoid adding these twice
             if path.segments().len() > 1 {
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/expr.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/expr.rs
index 4d66af9e8d5b..3192b21cfb2e 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions/expr.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/expr.rs
@@ -165,7 +165,11 @@ pub(crate) fn complete_expr_path(
                     hir::Adt::Struct(strukt) => {
                         let path = ctx
                             .module
-                            .find_use_path(ctx.db, hir::ModuleDef::from(strukt))
+                            .find_use_path(
+                                ctx.db,
+                                hir::ModuleDef::from(strukt),
+                                ctx.config.prefer_no_std,
+                            )
                             .filter(|it| it.len() > 1);
 
                         acc.add_struct_literal(ctx, path_ctx, strukt, path, None);
@@ -183,7 +187,11 @@ pub(crate) fn complete_expr_path(
                     hir::Adt::Union(un) => {
                         let path = ctx
                             .module
-                            .find_use_path(ctx.db, hir::ModuleDef::from(un))
+                            .find_use_path(
+                                ctx.db,
+                                hir::ModuleDef::from(un),
+                                ctx.config.prefer_no_std,
+                            )
                             .filter(|it| it.len() > 1);
 
                         acc.add_union_literal(ctx, un, path, None);
@@ -282,14 +290,26 @@ pub(crate) fn complete_expr_path(
                         }
                     }
 
-                    if let Some(ty) = innermost_ret_ty {
+                    if let Some(ret_ty) = innermost_ret_ty {
                         add_keyword(
                             "return",
-                            match (in_block_expr, ty.is_unit()) {
-                                (true, true) => "return ;",
-                                (true, false) => "return;",
-                                (false, true) => "return $0",
-                                (false, false) => "return",
+                            match (ret_ty.is_unit(), in_block_expr) {
+                                (true, true) => {
+                                    cov_mark::hit!(return_unit_block);
+                                    "return;"
+                                }
+                                (true, false) => {
+                                    cov_mark::hit!(return_unit_no_block);
+                                    "return"
+                                }
+                                (false, true) => {
+                                    cov_mark::hit!(return_value_block);
+                                    "return $0;"
+                                }
+                                (false, false) => {
+                                    cov_mark::hit!(return_value_no_block);
+                                    "return $0"
+                                }
                             },
                         );
                     }
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/flyimport.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/flyimport.rs
index f04cc15d7fab..364969af9c9a 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions/flyimport.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/flyimport.rs
@@ -262,7 +262,11 @@ fn import_on_the_fly(
 
     acc.add_all(
         import_assets
-            .search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind)
+            .search_for_imports(
+                &ctx.sema,
+                ctx.config.insert_use.prefix_kind,
+                ctx.config.prefer_no_std,
+            )
             .into_iter()
             .filter(ns_filter)
             .filter(|import| {
@@ -306,7 +310,11 @@ fn import_on_the_fly_pat_(
 
     acc.add_all(
         import_assets
-            .search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind)
+            .search_for_imports(
+                &ctx.sema,
+                ctx.config.insert_use.prefix_kind,
+                ctx.config.prefer_no_std,
+            )
             .into_iter()
             .filter(ns_filter)
             .filter(|import| {
@@ -344,7 +352,7 @@ fn import_on_the_fly_method(
     let user_input_lowercased = potential_import_name.to_lowercase();
 
     import_assets
-        .search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind)
+        .search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind, ctx.config.prefer_no_std)
         .into_iter()
         .filter(|import| {
             !ctx.is_item_hidden(&import.item_to_import)
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/mod_.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/mod_.rs
index 9c975b929533..950731eb4ca8 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions/mod_.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/mod_.rs
@@ -53,6 +53,7 @@ pub(crate) fn complete_mod(
     let existing_mod_declarations = current_module
         .children(ctx.db)
         .filter_map(|module| Some(module.name(ctx.db)?.to_string()))
+        .filter(|module| module != ctx.original_token.text())
         .collect::<FxHashSet<_>>();
 
     let module_declaration_file =
@@ -351,4 +352,23 @@ fn ignored_bar() {}
             "#]],
         );
     }
+
+    #[test]
+    fn semi_colon_completion() {
+        check(
+            r#"
+//- /lib.rs
+mod foo;
+//- /foo.rs
+mod bar {
+    mod baz$0
+}
+//- /foo/bar/baz.rs
+fn baz() {}
+"#,
+            expect![[r#"
+                md baz;
+            "#]],
+        );
+    }
 }
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/pattern.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/pattern.rs
index 71d2d9d434b4..58d5bf114cca 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions/pattern.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/pattern.rs
@@ -145,6 +145,7 @@ pub(crate) fn complete_pattern_path(
                             u.ty(ctx.db)
                         }
                         hir::PathResolution::Def(hir::ModuleDef::BuiltinType(ty)) => ty.ty(ctx.db),
+                        hir::PathResolution::Def(hir::ModuleDef::TypeAlias(ty)) => ty.ty(ctx.db),
                         _ => return,
                     };
 
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/postfix/format_like.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/postfix/format_like.rs
index b273a4cb53ba..b43bdb9ab9d1 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions/postfix/format_like.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/postfix/format_like.rs
@@ -16,8 +16,11 @@
 //
 // image::https://user-images.githubusercontent.com/48062697/113020656-b560f500-917a-11eb-87de-02991f61beb8.gif[]
 
-use ide_db::SnippetCap;
-use syntax::ast::{self, AstToken};
+use ide_db::{
+    syntax_helpers::format_string_exprs::{parse_format_exprs, with_placeholders},
+    SnippetCap,
+};
+use syntax::{ast, AstToken};
 
 use crate::{
     completions::postfix::build_postfix_snippet_builder, context::CompletionContext, Completions,
@@ -43,250 +46,24 @@ pub(crate) fn add_format_like_completions(
     cap: SnippetCap,
     receiver_text: &ast::String,
 ) {
-    let input = match string_literal_contents(receiver_text) {
-        // It's not a string literal, do not parse input.
-        Some(input) => input,
-        None => return,
-    };
-
     let postfix_snippet = match build_postfix_snippet_builder(ctx, cap, dot_receiver) {
         Some(it) => it,
         None => return,
     };
-    let mut parser = FormatStrParser::new(input);
 
-    if parser.parse().is_ok() {
+    if let Ok((out, exprs)) = parse_format_exprs(receiver_text.text()) {
+        let exprs = with_placeholders(exprs);
         for (label, macro_name) in KINDS {
-            let snippet = parser.to_suggestion(macro_name);
+            let snippet = format!(r#"{}({}, {})"#, macro_name, out, exprs.join(", "));
 
             postfix_snippet(label, macro_name, &snippet).add_to(acc);
         }
     }
 }
 
-/// Checks whether provided item is a string literal.
-fn string_literal_contents(item: &ast::String) -> Option<String> {
-    let item = item.text();
-    if item.len() >= 2 && item.starts_with('\"') && item.ends_with('\"') {
-        return Some(item[1..item.len() - 1].to_owned());
-    }
-
-    None
-}
-
-/// Parser for a format-like string. It is more allowing in terms of string contents,
-/// as we expect variable placeholders to be filled with expressions.
-#[derive(Debug)]
-pub(crate) struct FormatStrParser {
-    input: String,
-    output: String,
-    extracted_expressions: Vec<String>,
-    state: State,
-    parsed: bool,
-}
-
-#[derive(Debug, Clone, Copy, PartialEq)]
-enum State {
-    NotExpr,
-    MaybeExpr,
-    Expr,
-    MaybeIncorrect,
-    FormatOpts,
-}
-
-impl FormatStrParser {
-    pub(crate) fn new(input: String) -> Self {
-        Self {
-            input,
-            output: String::new(),
-            extracted_expressions: Vec::new(),
-            state: State::NotExpr,
-            parsed: false,
-        }
-    }
-
-    pub(crate) fn parse(&mut self) -> Result<(), ()> {
-        let mut current_expr = String::new();
-
-        let mut placeholder_id = 1;
-
-        // Count of open braces inside of an expression.
-        // We assume that user knows what they're doing, thus we treat it like a correct pattern, e.g.
-        // "{MyStruct { val_a: 0, val_b: 1 }}".
-        let mut inexpr_open_count = 0;
-
-        // We need to escape '\' and '$'. See the comments on `get_receiver_text()` for detail.
-        let mut chars = self.input.chars().peekable();
-        while let Some(chr) = chars.next() {
-            match (self.state, chr) {
-                (State::NotExpr, '{') => {
-                    self.output.push(chr);
-                    self.state = State::MaybeExpr;
-                }
-                (State::NotExpr, '}') => {
-                    self.output.push(chr);
-                    self.state = State::MaybeIncorrect;
-                }
-                (State::NotExpr, _) => {
-                    if matches!(chr, '\\' | '$') {
-                        self.output.push('\\');
-                    }
-                    self.output.push(chr);
-                }
-                (State::MaybeIncorrect, '}') => {
-                    // It's okay, we met "}}".
-                    self.output.push(chr);
-                    self.state = State::NotExpr;
-                }
-                (State::MaybeIncorrect, _) => {
-                    // Error in the string.
-                    return Err(());
-                }
-                (State::MaybeExpr, '{') => {
-                    self.output.push(chr);
-                    self.state = State::NotExpr;
-                }
-                (State::MaybeExpr, '}') => {
-                    // This is an empty sequence '{}'. Replace it with placeholder.
-                    self.output.push(chr);
-                    self.extracted_expressions.push(format!("${}", placeholder_id));
-                    placeholder_id += 1;
-                    self.state = State::NotExpr;
-                }
-                (State::MaybeExpr, _) => {
-                    if matches!(chr, '\\' | '$') {
-                        current_expr.push('\\');
-                    }
-                    current_expr.push(chr);
-                    self.state = State::Expr;
-                }
-                (State::Expr, '}') => {
-                    if inexpr_open_count == 0 {
-                        self.output.push(chr);
-                        self.extracted_expressions.push(current_expr.trim().into());
-                        current_expr = String::new();
-                        self.state = State::NotExpr;
-                    } else {
-                        // We're closing one brace met before inside of the expression.
-                        current_expr.push(chr);
-                        inexpr_open_count -= 1;
-                    }
-                }
-                (State::Expr, ':') if chars.peek().copied() == Some(':') => {
-                    // path separator
-                    current_expr.push_str("::");
-                    chars.next();
-                }
-                (State::Expr, ':') => {
-                    if inexpr_open_count == 0 {
-                        // We're outside of braces, thus assume that it's a specifier, like "{Some(value):?}"
-                        self.output.push(chr);
-                        self.extracted_expressions.push(current_expr.trim().into());
-                        current_expr = String::new();
-                        self.state = State::FormatOpts;
-                    } else {
-                        // We're inside of braced expression, assume that it's a struct field name/value delimiter.
-                        current_expr.push(chr);
-                    }
-                }
-                (State::Expr, '{') => {
-                    current_expr.push(chr);
-                    inexpr_open_count += 1;
-                }
-                (State::Expr, _) => {
-                    if matches!(chr, '\\' | '$') {
-                        current_expr.push('\\');
-                    }
-                    current_expr.push(chr);
-                }
-                (State::FormatOpts, '}') => {
-                    self.output.push(chr);
-                    self.state = State::NotExpr;
-                }
-                (State::FormatOpts, _) => {
-                    if matches!(chr, '\\' | '$') {
-                        self.output.push('\\');
-                    }
-                    self.output.push(chr);
-                }
-            }
-        }
-
-        if self.state != State::NotExpr {
-            return Err(());
-        }
-
-        self.parsed = true;
-        Ok(())
-    }
-
-    pub(crate) fn to_suggestion(&self, macro_name: &str) -> String {
-        assert!(self.parsed, "Attempt to get a suggestion from not parsed expression");
-
-        let expressions_as_string = self.extracted_expressions.join(", ");
-        format!(r#"{}("{}", {})"#, macro_name, self.output, expressions_as_string)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
-    use expect_test::{expect, Expect};
-
-    fn check(input: &str, expect: &Expect) {
-        let mut parser = FormatStrParser::new((*input).to_owned());
-        let outcome_repr = if parser.parse().is_ok() {
-            // Parsing should be OK, expected repr is "string; expr_1, expr_2".
-            if parser.extracted_expressions.is_empty() {
-                parser.output
-            } else {
-                format!("{}; {}", parser.output, parser.extracted_expressions.join(", "))
-            }
-        } else {
-            // Parsing should fail, expected repr is "-".
-            "-".to_owned()
-        };
-
-        expect.assert_eq(&outcome_repr);
-    }
-
-    #[test]
-    fn format_str_parser() {
-        let test_vector = &[
-            ("no expressions", expect![["no expressions"]]),
-            (r"no expressions with \$0$1", expect![r"no expressions with \\\$0\$1"]),
-            ("{expr} is {2 + 2}", expect![["{} is {}; expr, 2 + 2"]]),
-            ("{expr:?}", expect![["{:?}; expr"]]),
-            ("{expr:1$}", expect![[r"{:1\$}; expr"]]),
-            ("{$0}", expect![[r"{}; \$0"]]),
-            ("{malformed", expect![["-"]]),
-            ("malformed}", expect![["-"]]),
-            ("{{correct", expect![["{{correct"]]),
-            ("correct}}", expect![["correct}}"]]),
-            ("{correct}}}", expect![["{}}}; correct"]]),
-            ("{correct}}}}}", expect![["{}}}}}; correct"]]),
-            ("{incorrect}}", expect![["-"]]),
-            ("placeholders {} {}", expect![["placeholders {} {}; $1, $2"]]),
-            ("mixed {} {2 + 2} {}", expect![["mixed {} {} {}; $1, 2 + 2, $2"]]),
-            (
-                "{SomeStruct { val_a: 0, val_b: 1 }}",
-                expect![["{}; SomeStruct { val_a: 0, val_b: 1 }"]],
-            ),
-            ("{expr:?} is {2.32f64:.5}", expect![["{:?} is {:.5}; expr, 2.32f64"]]),
-            (
-                "{SomeStruct { val_a: 0, val_b: 1 }:?}",
-                expect![["{:?}; SomeStruct { val_a: 0, val_b: 1 }"]],
-            ),
-            ("{     2 + 2        }", expect![["{}; 2 + 2"]]),
-            ("{strsim::jaro_winkle(a)}", expect![["{}; strsim::jaro_winkle(a)"]]),
-            ("{foo::bar::baz()}", expect![["{}; foo::bar::baz()"]]),
-            ("{foo::bar():?}", expect![["{:?}; foo::bar()"]]),
-        ];
-
-        for (input, output) in test_vector {
-            check(input, output)
-        }
-    }
 
     #[test]
     fn test_into_suggestion() {
@@ -302,10 +79,10 @@ mod tests {
         ];
 
         for (kind, input, output) in test_vector {
-            let mut parser = FormatStrParser::new((*input).to_owned());
-            parser.parse().expect("Parsing must succeed");
-
-            assert_eq!(&parser.to_suggestion(*kind), output);
+            let (parsed_string, exprs) = parse_format_exprs(input).unwrap();
+            let exprs = with_placeholders(exprs);
+            let snippet = format!(r#"{}("{}", {})"#, kind, parsed_string, exprs.join(", "));
+            assert_eq!(&snippet, output);
         }
     }
 }
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/config.rs b/src/tools/rust-analyzer/crates/ide-completion/src/config.rs
index 80d6af28168f..a0f5e81b4fb6 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/config.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/config.rs
@@ -17,6 +17,7 @@ pub struct CompletionConfig {
     pub callable: Option<CallableSnippets>,
     pub snippet_cap: Option<SnippetCap>,
     pub insert_use: InsertUseConfig,
+    pub prefer_no_std: bool,
     pub snippets: Vec<Snippet>,
 }
 
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs b/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
index ae1a440d06da..8d21f4fce0a2 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
@@ -234,7 +234,12 @@ pub fn resolve_completion_edits(
         );
         let import = items_with_name
             .filter_map(|candidate| {
-                current_module.find_use_path_prefixed(db, candidate, config.insert_use.prefix_kind)
+                current_module.find_use_path_prefixed(
+                    db,
+                    candidate,
+                    config.insert_use.prefix_kind,
+                    config.prefer_no_std,
+                )
             })
             .find(|mod_path| mod_path.to_string() == full_import_path);
         if let Some(import_path) = import {
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/snippet.rs b/src/tools/rust-analyzer/crates/ide-completion/src/snippet.rs
index dc1039fa623e..f3b8eae4fe8c 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/snippet.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/snippet.rs
@@ -174,8 +174,12 @@ fn import_edits(ctx: &CompletionContext<'_>, requires: &[GreenNode]) -> Option<V
             hir::PathResolution::Def(def) => def.into(),
             _ => return None,
         };
-        let path =
-            ctx.module.find_use_path_prefixed(ctx.db, item, ctx.config.insert_use.prefix_kind)?;
+        let path = ctx.module.find_use_path_prefixed(
+            ctx.db,
+            item,
+            ctx.config.insert_use.prefix_kind,
+            ctx.config.prefer_no_std,
+        )?;
         Some((path.len() > 1).then(|| LocatedImport::new(path.clone(), item, item, None)))
     };
     let mut res = Vec::with_capacity(requires.len());
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/tests.rs b/src/tools/rust-analyzer/crates/ide-completion/src/tests.rs
index cf826648dcf7..9e2beb9ee328 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/tests.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/tests.rs
@@ -66,6 +66,7 @@ pub(crate) const TEST_CONFIG: CompletionConfig = CompletionConfig {
     enable_private_editable: false,
     callable: Some(CallableSnippets::FillArguments),
     snippet_cap: SnippetCap::new(true),
+    prefer_no_std: false,
     insert_use: InsertUseConfig {
         granularity: ImportGranularity::Crate,
         prefix_kind: PrefixKind::Plain,
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs b/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs
index 925081ebf660..8e26d889f9b6 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/tests/expression.rs
@@ -1,7 +1,7 @@
 //! Completion tests for expressions.
 use expect_test::{expect, Expect};
 
-use crate::tests::{completion_list, BASE_ITEMS_FIXTURE};
+use crate::tests::{check_edit, completion_list, BASE_ITEMS_FIXTURE};
 
 fn check(ra_fixture: &str, expect: Expect) {
     let actual = completion_list(&format!("{}{}", BASE_ITEMS_FIXTURE, ra_fixture));
@@ -670,3 +670,78 @@ fn main() {
         "#]],
     );
 }
+
+#[test]
+fn varaiant_with_struct() {
+    check_empty(
+        r#"
+pub struct YoloVariant {
+    pub f: usize
+}
+
+pub enum HH {
+    Yolo(YoloVariant),
+}
+
+fn brr() {
+    let t = HH::Yolo(Y$0);
+}
+"#,
+        expect![[r#"
+            en HH
+            fn brr()           fn()
+            st YoloVariant
+            st YoloVariant {…} YoloVariant { f: usize }
+            bt u32
+            kw crate::
+            kw false
+            kw for
+            kw if
+            kw if let
+            kw loop
+            kw match
+            kw return
+            kw self::
+            kw true
+            kw unsafe
+            kw while
+            kw while let
+        "#]],
+    );
+}
+
+#[test]
+fn return_unit_block() {
+    cov_mark::check!(return_unit_block);
+    check_edit("return", r#"fn f() { if true { $0 } }"#, r#"fn f() { if true { return; } }"#);
+}
+
+#[test]
+fn return_unit_no_block() {
+    cov_mark::check!(return_unit_no_block);
+    check_edit(
+        "return",
+        r#"fn f() { match () { () => $0 } }"#,
+        r#"fn f() { match () { () => return } }"#,
+    );
+}
+
+#[test]
+fn return_value_block() {
+    cov_mark::check!(return_value_block);
+    check_edit(
+        "return",
+        r#"fn f() -> i32 { if true { $0 } }"#,
+        r#"fn f() -> i32 { if true { return $0; } }"#,
+    );
+}
+
+#[test]
+fn return_value_no_block() {
+    cov_mark::check!(return_value_no_block);
+    check_edit(
+        "return",
+        r#"fn f() -> i32 { match () { () => $0 } }"#,
+        r#"fn f() -> i32 { match () { () => return $0 } }"#,
+    );
+}
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/tests/pattern.rs b/src/tools/rust-analyzer/crates/ide-completion/src/tests/pattern.rs
index 85c4dbd6625d..db8bef66405e 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/tests/pattern.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/tests/pattern.rs
@@ -714,3 +714,30 @@ impl Ty {
         "#]],
     );
 }
+
+#[test]
+fn through_alias() {
+    check_empty(
+        r#"
+enum Enum<T> {
+    Unit,
+    Tuple(T),
+}
+
+type EnumAlias<T> = Enum<T>;
+
+fn f(x: EnumAlias<u8>) {
+    match x {
+        EnumAlias::$0 => (),
+        _ => (),
+    }
+
+}
+
+"#,
+        expect![[r#"
+            bn Tuple(…) Tuple($1)$0
+            bn Unit     Unit$0
+        "#]],
+    );
+}
diff --git a/src/tools/rust-analyzer/crates/ide-db/Cargo.toml b/src/tools/rust-analyzer/crates/ide-db/Cargo.toml
index a1b0bd6cb304..30272bc16f63 100644
--- a/src/tools/rust-analyzer/crates/ide-db/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/ide-db/Cargo.toml
@@ -20,6 +20,7 @@ either = "1.7.0"
 itertools = "0.10.3"
 arrayvec = "0.7.2"
 indexmap = "1.9.1"
+memchr = "2.5.0"
 
 stdx = { path = "../stdx", version = "0.0.0" }
 parser = { path = "../parser", version = "0.0.0" }
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/active_parameter.rs b/src/tools/rust-analyzer/crates/ide-db/src/active_parameter.rs
index 7303ef8b7bb5..7109c6fd188f 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/active_parameter.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/active_parameter.rs
@@ -12,7 +12,7 @@ use crate::RootDatabase;
 #[derive(Debug)]
 pub struct ActiveParameter {
     pub ty: Type,
-    pub pat: Either<ast::SelfParam, ast::Pat>,
+    pub pat: Option<Either<ast::SelfParam, ast::Pat>>,
 }
 
 impl ActiveParameter {
@@ -27,12 +27,12 @@ impl ActiveParameter {
             return None;
         }
         let (pat, ty) = params.swap_remove(idx);
-        pat.map(|pat| ActiveParameter { ty, pat })
+        Some(ActiveParameter { ty, pat })
     }
 
     pub fn ident(&self) -> Option<ast::Name> {
-        self.pat.as_ref().right().and_then(|param| match param {
-            ast::Pat::IdentPat(ident) => ident.name(),
+        self.pat.as_ref().and_then(|param| match param {
+            Either::Right(ast::Pat::IdentPat(ident)) => ident.name(),
             _ => None,
         })
     }
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/imports/import_assets.rs b/src/tools/rust-analyzer/crates/ide-db/src/imports/import_assets.rs
index 26ef86155e53..40a6a3e8970f 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/imports/import_assets.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/imports/import_assets.rs
@@ -212,18 +212,20 @@ impl ImportAssets {
         &self,
         sema: &Semantics<'_, RootDatabase>,
         prefix_kind: PrefixKind,
+        prefer_no_std: bool,
     ) -> Vec<LocatedImport> {
         let _p = profile::span("import_assets::search_for_imports");
-        self.search_for(sema, Some(prefix_kind))
+        self.search_for(sema, Some(prefix_kind), prefer_no_std)
     }
 
     /// This may return non-absolute paths if a part of the returned path is already imported into scope.
     pub fn search_for_relative_paths(
         &self,
         sema: &Semantics<'_, RootDatabase>,
+        prefer_no_std: bool,
     ) -> Vec<LocatedImport> {
         let _p = profile::span("import_assets::search_for_relative_paths");
-        self.search_for(sema, None)
+        self.search_for(sema, None, prefer_no_std)
     }
 
     pub fn path_fuzzy_name_to_exact(&mut self, case_sensitive: bool) {
@@ -242,6 +244,7 @@ impl ImportAssets {
         &self,
         sema: &Semantics<'_, RootDatabase>,
         prefixed: Option<PrefixKind>,
+        prefer_no_std: bool,
     ) -> Vec<LocatedImport> {
         let _p = profile::span("import_assets::search_for");
 
@@ -252,6 +255,7 @@ impl ImportAssets {
                 item_for_path_search(sema.db, item)?,
                 &self.module_with_candidate,
                 prefixed,
+                prefer_no_std,
             )
         };
 
@@ -564,11 +568,12 @@ fn get_mod_path(
     item_to_search: ItemInNs,
     module_with_candidate: &Module,
     prefixed: Option<PrefixKind>,
+    prefer_no_std: bool,
 ) -> Option<ModPath> {
     if let Some(prefix_kind) = prefixed {
-        module_with_candidate.find_use_path_prefixed(db, item_to_search, prefix_kind)
+        module_with_candidate.find_use_path_prefixed(db, item_to_search, prefix_kind, prefer_no_std)
     } else {
-        module_with_candidate.find_use_path(db, item_to_search)
+        module_with_candidate.find_use_path(db, item_to_search, prefer_no_std)
     }
 }
 
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/imports/insert_use.rs b/src/tools/rust-analyzer/crates/ide-db/src/imports/insert_use.rs
index c14182279d05..9be1d3663493 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/imports/insert_use.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/imports/insert_use.rs
@@ -7,7 +7,10 @@ use std::cmp::Ordering;
 use hir::Semantics;
 use syntax::{
     algo,
-    ast::{self, make, AstNode, HasAttrs, HasModuleItem, HasVisibility, PathSegmentKind},
+    ast::{
+        self, edit_in_place::Removable, make, AstNode, HasAttrs, HasModuleItem, HasVisibility,
+        PathSegmentKind,
+    },
     ted, Direction, NodeOrToken, SyntaxKind, SyntaxNode,
 };
 
@@ -192,20 +195,24 @@ pub fn insert_use(scope: &ImportScope, path: ast::Path, cfg: &InsertUseConfig) {
     insert_use_(scope, &path, cfg.group, use_item);
 }
 
-pub fn remove_path_if_in_use_stmt(path: &ast::Path) {
+pub fn ast_to_remove_for_path_in_use_stmt(path: &ast::Path) -> Option<Box<dyn Removable>> {
     // FIXME: improve this
     if path.parent_path().is_some() {
-        return;
+        return None;
     }
-    if let Some(use_tree) = path.syntax().parent().and_then(ast::UseTree::cast) {
-        if use_tree.use_tree_list().is_some() || use_tree.star_token().is_some() {
-            return;
-        }
-        if let Some(use_) = use_tree.syntax().parent().and_then(ast::Use::cast) {
-            use_.remove();
-            return;
-        }
-        use_tree.remove();
+    let use_tree = path.syntax().parent().and_then(ast::UseTree::cast)?;
+    if use_tree.use_tree_list().is_some() || use_tree.star_token().is_some() {
+        return None;
+    }
+    if let Some(use_) = use_tree.syntax().parent().and_then(ast::Use::cast) {
+        return Some(Box::new(use_));
+    }
+    Some(Box::new(use_tree))
+}
+
+pub fn remove_path_if_in_use_stmt(path: &ast::Path) {
+    if let Some(node) = ast_to_remove_for_path_in_use_stmt(path) {
+        node.remove();
     }
 }
 
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/lib.rs b/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
index 1ec62a8425a3..e0bc0f89f0a1 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
@@ -38,6 +38,7 @@ pub mod syntax_helpers {
     pub mod node_ext;
     pub mod insert_whitespace_into_node;
     pub mod format_string;
+    pub mod format_string_exprs;
 
     pub use parser::LexedStr;
 }
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/path_transform.rs b/src/tools/rust-analyzer/crates/ide-db/src/path_transform.rs
index 40af9e6fe2ad..12d873b4a0aa 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/path_transform.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/path_transform.rs
@@ -173,6 +173,7 @@ impl<'a> Ctx<'a> {
                             let found_path = self.target_module.find_use_path(
                                 self.source_scope.db.upcast(),
                                 hir::ModuleDef::Trait(trait_ref),
+                                false,
                             )?;
                             match ast::make::ty_path(mod_path_to_ast(&found_path)) {
                                 ast::Type::PathType(path_ty) => Some(path_ty),
@@ -209,7 +210,7 @@ impl<'a> Ctx<'a> {
                 }
 
                 let found_path =
-                    self.target_module.find_use_path(self.source_scope.db.upcast(), def)?;
+                    self.target_module.find_use_path(self.source_scope.db.upcast(), def, false)?;
                 let res = mod_path_to_ast(&found_path).clone_for_update();
                 if let Some(args) = path.segment().and_then(|it| it.generic_arg_list()) {
                     if let Some(segment) = res.segment() {
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/search.rs b/src/tools/rust-analyzer/crates/ide-db/src/search.rs
index 7deffe8e0f63..7cabdb55e8d2 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/search.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/search.rs
@@ -8,7 +8,9 @@ use std::{mem, sync::Arc};
 
 use base_db::{FileId, FileRange, SourceDatabase, SourceDatabaseExt};
 use hir::{DefWithBody, HasAttrs, HasSource, InFile, ModuleSource, Semantics, Visibility};
+use memchr::memmem::Finder;
 use once_cell::unsync::Lazy;
+use parser::SyntaxKind;
 use stdx::hash::NoHashHashMap;
 use syntax::{ast, match_ast, AstNode, TextRange, TextSize};
 
@@ -67,6 +69,7 @@ pub enum ReferenceCategory {
     // Create
     Write,
     Read,
+    Import,
     // FIXME: Some day should be able to search in doc comments. Would probably
     // need to switch from enum to bitflags then?
     // DocComment
@@ -409,14 +412,17 @@ impl<'a> FindUsages<'a> {
             Some(s) => s.as_str(),
             None => return,
         };
+        let finder = &Finder::new(name);
+        let include_self_kw_refs =
+            self.include_self_kw_refs.as_ref().map(|ty| (ty, Finder::new("Self")));
 
-        // these can't be closures because rust infers the lifetimes wrong ...
+        // for<'a> |text: &'a str, name: &'a str, search_range: TextRange| -> impl Iterator<Item = TextSize> + 'a { ... }
         fn match_indices<'a>(
             text: &'a str,
-            name: &'a str,
+            finder: &'a Finder<'a>,
             search_range: TextRange,
         ) -> impl Iterator<Item = TextSize> + 'a {
-            text.match_indices(name).filter_map(move |(idx, _)| {
+            finder.find_iter(text.as_bytes()).filter_map(move |idx| {
                 let offset: TextSize = idx.try_into().unwrap();
                 if !search_range.contains_inclusive(offset) {
                     return None;
@@ -425,6 +431,7 @@ impl<'a> FindUsages<'a> {
             })
         }
 
+        // for<'a> |scope: &'a SearchScope| -> impl Iterator<Item = (Arc<String>, FileId, TextRange)> + 'a { ... }
         fn scope_files<'a>(
             sema: &'a Semantics<'_, RootDatabase>,
             scope: &'a SearchScope,
@@ -448,7 +455,7 @@ impl<'a> FindUsages<'a> {
             let tree = Lazy::new(move || sema.parse(file_id).syntax().clone());
 
             // Search for occurrences of the items name
-            for offset in match_indices(&text, name, search_range) {
+            for offset in match_indices(&text, finder, search_range) {
                 for name in sema.find_nodes_at_offset_with_descend(&tree, offset) {
                     if match name {
                         ast::NameLike::NameRef(name_ref) => self.found_name_ref(&name_ref, sink),
@@ -460,8 +467,8 @@ impl<'a> FindUsages<'a> {
                 }
             }
             // Search for occurrences of the `Self` referring to our type
-            if let Some(self_ty) = &self.include_self_kw_refs {
-                for offset in match_indices(&text, "Self", search_range) {
+            if let Some((self_ty, finder)) = &include_self_kw_refs {
+                for offset in match_indices(&text, finder, search_range) {
                     for name_ref in sema.find_nodes_at_offset_with_descend(&tree, offset) {
                         if self.found_self_ty_name_ref(self_ty, &name_ref, sink) {
                             return;
@@ -477,20 +484,22 @@ impl<'a> FindUsages<'a> {
                 let scope = search_scope
                     .intersection(&SearchScope::module_and_children(self.sema.db, module));
 
-                let is_crate_root = module.is_crate_root(self.sema.db);
+                let is_crate_root =
+                    module.is_crate_root(self.sema.db).then(|| Finder::new("crate"));
+                let finder = &Finder::new("super");
 
                 for (text, file_id, search_range) in scope_files(sema, &scope) {
                     let tree = Lazy::new(move || sema.parse(file_id).syntax().clone());
 
-                    for offset in match_indices(&text, "super", search_range) {
+                    for offset in match_indices(&text, finder, search_range) {
                         for name_ref in sema.find_nodes_at_offset_with_descend(&tree, offset) {
                             if self.found_name_ref(&name_ref, sink) {
                                 return;
                             }
                         }
                     }
-                    if is_crate_root {
-                        for offset in match_indices(&text, "crate", search_range) {
+                    if let Some(finder) = &is_crate_root {
+                        for offset in match_indices(&text, finder, search_range) {
                             for name_ref in sema.find_nodes_at_offset_with_descend(&tree, offset) {
                                 if self.found_name_ref(&name_ref, sink) {
                                     return;
@@ -531,8 +540,9 @@ impl<'a> FindUsages<'a> {
                     search_range.unwrap_or_else(|| TextRange::up_to(TextSize::of(text.as_str())));
 
                 let tree = Lazy::new(|| sema.parse(file_id).syntax().clone());
+                let finder = &Finder::new("self");
 
-                for offset in match_indices(&text, "self", search_range) {
+                for offset in match_indices(&text, finder, search_range) {
                     for name_ref in sema.find_nodes_at_offset_with_descend(&tree, offset) {
                         if self.found_self_module_name_ref(&name_ref, sink) {
                             return;
@@ -577,7 +587,7 @@ impl<'a> FindUsages<'a> {
                 let reference = FileReference {
                     range,
                     name: ast::NameLike::NameRef(name_ref.clone()),
-                    category: None,
+                    category: is_name_ref_in_import(name_ref).then(|| ReferenceCategory::Import),
                 };
                 sink(file_id, reference)
             }
@@ -756,7 +766,7 @@ impl ReferenceCategory {
     fn new(def: &Definition, r: &ast::NameRef) -> Option<ReferenceCategory> {
         // Only Locals and Fields have accesses for now.
         if !matches!(def, Definition::Local(_) | Definition::Field(_)) {
-            return None;
+            return is_name_ref_in_import(r).then(|| ReferenceCategory::Import);
         }
 
         let mode = r.syntax().ancestors().find_map(|node| {
@@ -783,3 +793,12 @@ impl ReferenceCategory {
         mode.or(Some(ReferenceCategory::Read))
     }
 }
+
+fn is_name_ref_in_import(name_ref: &ast::NameRef) -> bool {
+    name_ref
+        .syntax()
+        .parent()
+        .and_then(ast::PathSegment::cast)
+        .and_then(|it| it.parent_path().top_path().syntax().parent())
+        .map_or(false, |it| it.kind() == SyntaxKind::USE_TREE)
+}
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/format_string_exprs.rs b/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/format_string_exprs.rs
new file mode 100644
index 000000000000..ac6c6e8feeea
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/format_string_exprs.rs
@@ -0,0 +1,267 @@
+//! Tools to work with expressions present in format string literals for the `format_args!` family of macros.
+//! Primarily meant for assists and completions.
+
+/// Enum for represenging extraced format string args.
+/// Can either be extracted expressions (which includes identifiers),
+/// or placeholders `{}`.
+#[derive(Debug, PartialEq, Eq)]
+pub enum Arg {
+    Placeholder,
+    Ident(String),
+    Expr(String),
+}
+
+/**
+ Add placeholders like `$1` and `$2` in place of [`Arg::Placeholder`],
+ and unwraps the [`Arg::Ident`] and [`Arg::Expr`] enums.
+ ```rust
+ # use ide_db::syntax_helpers::format_string_exprs::*;
+ assert_eq!(with_placeholders(vec![Arg::Ident("ident".to_owned()), Arg::Placeholder, Arg::Expr("expr + 2".to_owned())]), vec!["ident".to_owned(), "$1".to_owned(), "expr + 2".to_owned()])
+ ```
+*/
+
+pub fn with_placeholders(args: Vec<Arg>) -> Vec<String> {
+    let mut placeholder_id = 1;
+    args.into_iter()
+        .map(move |a| match a {
+            Arg::Expr(s) | Arg::Ident(s) => s,
+            Arg::Placeholder => {
+                let s = format!("${placeholder_id}");
+                placeholder_id += 1;
+                s
+            }
+        })
+        .collect()
+}
+
+/**
+ Parser for a format-like string. It is more allowing in terms of string contents,
+ as we expect variable placeholders to be filled with expressions.
+
+ Built for completions and assists, and escapes `\` and `$` in output.
+ (See the comments on `get_receiver_text()` for detail.)
+ Splits a format string that may contain expressions
+ like
+ ```rust
+ assert_eq!(parse("{ident} {} {expr + 42} ").unwrap(), ("{} {} {}", vec![Arg::Ident("ident"), Arg::Placeholder, Arg::Expr("expr + 42")]));
+ ```
+*/
+pub fn parse_format_exprs(input: &str) -> Result<(String, Vec<Arg>), ()> {
+    #[derive(Debug, Clone, Copy, PartialEq)]
+    enum State {
+        NotArg,
+        MaybeArg,
+        Expr,
+        Ident,
+        MaybeIncorrect,
+        FormatOpts,
+    }
+
+    let mut state = State::NotArg;
+    let mut current_expr = String::new();
+    let mut extracted_expressions = Vec::new();
+    let mut output = String::new();
+
+    // Count of open braces inside of an expression.
+    // We assume that user knows what they're doing, thus we treat it like a correct pattern, e.g.
+    // "{MyStruct { val_a: 0, val_b: 1 }}".
+    let mut inexpr_open_count = 0;
+
+    let mut chars = input.chars().peekable();
+    while let Some(chr) = chars.next() {
+        match (state, chr) {
+            (State::NotArg, '{') => {
+                output.push(chr);
+                state = State::MaybeArg;
+            }
+            (State::NotArg, '}') => {
+                output.push(chr);
+                state = State::MaybeIncorrect;
+            }
+            (State::NotArg, _) => {
+                if matches!(chr, '\\' | '$') {
+                    output.push('\\');
+                }
+                output.push(chr);
+            }
+            (State::MaybeIncorrect, '}') => {
+                // It's okay, we met "}}".
+                output.push(chr);
+                state = State::NotArg;
+            }
+            (State::MaybeIncorrect, _) => {
+                // Error in the string.
+                return Err(());
+            }
+            // Escaped braces `{{`
+            (State::MaybeArg, '{') => {
+                output.push(chr);
+                state = State::NotArg;
+            }
+            (State::MaybeArg, '}') => {
+                // This is an empty sequence '{}'.
+                output.push(chr);
+                extracted_expressions.push(Arg::Placeholder);
+                state = State::NotArg;
+            }
+            (State::MaybeArg, _) => {
+                if matches!(chr, '\\' | '$') {
+                    current_expr.push('\\');
+                }
+                current_expr.push(chr);
+
+                // While Rust uses the unicode sets of XID_start and XID_continue for Identifiers
+                // this is probably the best we can do to avoid a false positive
+                if chr.is_alphabetic() || chr == '_' {
+                    state = State::Ident;
+                } else {
+                    state = State::Expr;
+                }
+            }
+            (State::Ident | State::Expr, '}') => {
+                if inexpr_open_count == 0 {
+                    output.push(chr);
+
+                    if matches!(state, State::Expr) {
+                        extracted_expressions.push(Arg::Expr(current_expr.trim().into()));
+                    } else {
+                        extracted_expressions.push(Arg::Ident(current_expr.trim().into()));
+                    }
+
+                    current_expr = String::new();
+                    state = State::NotArg;
+                } else {
+                    // We're closing one brace met before inside of the expression.
+                    current_expr.push(chr);
+                    inexpr_open_count -= 1;
+                }
+            }
+            (State::Ident | State::Expr, ':') if matches!(chars.peek(), Some(':')) => {
+                // path separator
+                state = State::Expr;
+                current_expr.push_str("::");
+                chars.next();
+            }
+            (State::Ident | State::Expr, ':') => {
+                if inexpr_open_count == 0 {
+                    // We're outside of braces, thus assume that it's a specifier, like "{Some(value):?}"
+                    output.push(chr);
+
+                    if matches!(state, State::Expr) {
+                        extracted_expressions.push(Arg::Expr(current_expr.trim().into()));
+                    } else {
+                        extracted_expressions.push(Arg::Ident(current_expr.trim().into()));
+                    }
+
+                    current_expr = String::new();
+                    state = State::FormatOpts;
+                } else {
+                    // We're inside of braced expression, assume that it's a struct field name/value delimiter.
+                    current_expr.push(chr);
+                }
+            }
+            (State::Ident | State::Expr, '{') => {
+                state = State::Expr;
+                current_expr.push(chr);
+                inexpr_open_count += 1;
+            }
+            (State::Ident | State::Expr, _) => {
+                if !(chr.is_alphanumeric() || chr == '_' || chr == '#') {
+                    state = State::Expr;
+                }
+
+                if matches!(chr, '\\' | '$') {
+                    current_expr.push('\\');
+                }
+                current_expr.push(chr);
+            }
+            (State::FormatOpts, '}') => {
+                output.push(chr);
+                state = State::NotArg;
+            }
+            (State::FormatOpts, _) => {
+                if matches!(chr, '\\' | '$') {
+                    output.push('\\');
+                }
+                output.push(chr);
+            }
+        }
+    }
+
+    if state != State::NotArg {
+        return Err(());
+    }
+
+    Ok((output, extracted_expressions))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use expect_test::{expect, Expect};
+
+    fn check(input: &str, expect: &Expect) {
+        let (output, exprs) = parse_format_exprs(input).unwrap_or(("-".to_string(), vec![]));
+        let outcome_repr = if !exprs.is_empty() {
+            format!("{}; {}", output, with_placeholders(exprs).join(", "))
+        } else {
+            output
+        };
+
+        expect.assert_eq(&outcome_repr);
+    }
+
+    #[test]
+    fn format_str_parser() {
+        let test_vector = &[
+            ("no expressions", expect![["no expressions"]]),
+            (r"no expressions with \$0$1", expect![r"no expressions with \\\$0\$1"]),
+            ("{expr} is {2 + 2}", expect![["{} is {}; expr, 2 + 2"]]),
+            ("{expr:?}", expect![["{:?}; expr"]]),
+            ("{expr:1$}", expect![[r"{:1\$}; expr"]]),
+            ("{$0}", expect![[r"{}; \$0"]]),
+            ("{malformed", expect![["-"]]),
+            ("malformed}", expect![["-"]]),
+            ("{{correct", expect![["{{correct"]]),
+            ("correct}}", expect![["correct}}"]]),
+            ("{correct}}}", expect![["{}}}; correct"]]),
+            ("{correct}}}}}", expect![["{}}}}}; correct"]]),
+            ("{incorrect}}", expect![["-"]]),
+            ("placeholders {} {}", expect![["placeholders {} {}; $1, $2"]]),
+            ("mixed {} {2 + 2} {}", expect![["mixed {} {} {}; $1, 2 + 2, $2"]]),
+            (
+                "{SomeStruct { val_a: 0, val_b: 1 }}",
+                expect![["{}; SomeStruct { val_a: 0, val_b: 1 }"]],
+            ),
+            ("{expr:?} is {2.32f64:.5}", expect![["{:?} is {:.5}; expr, 2.32f64"]]),
+            (
+                "{SomeStruct { val_a: 0, val_b: 1 }:?}",
+                expect![["{:?}; SomeStruct { val_a: 0, val_b: 1 }"]],
+            ),
+            ("{     2 + 2        }", expect![["{}; 2 + 2"]]),
+            ("{strsim::jaro_winkle(a)}", expect![["{}; strsim::jaro_winkle(a)"]]),
+            ("{foo::bar::baz()}", expect![["{}; foo::bar::baz()"]]),
+            ("{foo::bar():?}", expect![["{:?}; foo::bar()"]]),
+        ];
+
+        for (input, output) in test_vector {
+            check(input, output)
+        }
+    }
+
+    #[test]
+    fn arg_type() {
+        assert_eq!(
+            parse_format_exprs("{_ident} {r#raw_ident} {expr.obj} {name {thing: 42} } {}")
+                .unwrap()
+                .1,
+            vec![
+                Arg::Ident("_ident".to_owned()),
+                Arg::Ident("r#raw_ident".to_owned()),
+                Arg::Expr("expr.obj".to_owned()),
+                Arg::Expr("name {thing: 42}".to_owned()),
+                Arg::Placeholder
+            ]
+        );
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/insert_whitespace_into_node.rs b/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/insert_whitespace_into_node.rs
index f54ae6c92022..8bc093a85a21 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/insert_whitespace_into_node.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/insert_whitespace_into_node.rs
@@ -95,7 +95,7 @@ pub fn insert_ws_into(syn: SyntaxNode) -> SyntaxNode {
             AS_KW | DYN_KW | IMPL_KW | CONST_KW => {
                 mods.push(do_ws(after, tok));
             }
-            T![;] => {
+            T![;] if is_next(|it| it != R_CURLY, true) => {
                 if indent > 0 {
                     mods.push(do_indent(after, tok, indent));
                 }
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/node_ext.rs b/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/node_ext.rs
index 84bde4d44dbb..b890e2b58df8 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/node_ext.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/syntax_helpers/node_ext.rs
@@ -315,7 +315,6 @@ pub fn for_each_tail_expr(expr: &ast::Expr, cb: &mut dyn FnMut(&ast::Expr)) {
         | ast::Expr::IndexExpr(_)
         | ast::Expr::Literal(_)
         | ast::Expr::MacroExpr(_)
-        | ast::Expr::MacroStmts(_)
         | ast::Expr::MethodCallExpr(_)
         | ast::Expr::ParenExpr(_)
         | ast::Expr::PathExpr(_)
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/break_outside_of_loop.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/break_outside_of_loop.rs
index d12594a4ce5c..0c92e706b391 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/break_outside_of_loop.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/break_outside_of_loop.rs
@@ -7,9 +7,10 @@ pub(crate) fn break_outside_of_loop(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::BreakOutsideOfLoop,
 ) -> Diagnostic {
+    let construct = if d.is_break { "break" } else { "continue" };
     Diagnostic::new(
         "break-outside-of-loop",
-        "break outside of loop",
+        format!("{construct} outside of loop"),
         ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
     )
 }
@@ -19,11 +20,122 @@ mod tests {
     use crate::tests::check_diagnostics;
 
     #[test]
-    fn break_outside_of_loop() {
+    fn outside_of_loop() {
         check_diagnostics(
             r#"
-fn foo() { break; }
-         //^^^^^ error: break outside of loop
+fn foo() {
+    break;
+  //^^^^^ error: break outside of loop
+    break 'a;
+  //^^^^^^^^ error: break outside of loop
+    continue;
+  //^^^^^^^^ error: continue outside of loop
+    continue 'a;
+  //^^^^^^^^^^^ error: continue outside of loop
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn try_blocks_are_borders() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    'a: loop {
+        try {
+                break;
+              //^^^^^ error: break outside of loop
+                break 'a;
+              //^^^^^^^^ error: break outside of loop
+                continue;
+              //^^^^^^^^ error: continue outside of loop
+                continue 'a;
+              //^^^^^^^^^^^ error: continue outside of loop
+        };
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn async_blocks_are_borders() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    'a: loop {
+        try {
+                break;
+              //^^^^^ error: break outside of loop
+                break 'a;
+              //^^^^^^^^ error: break outside of loop
+                continue;
+              //^^^^^^^^ error: continue outside of loop
+                continue 'a;
+              //^^^^^^^^^^^ error: continue outside of loop
+        };
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn closures_are_borders() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    'a: loop {
+        try {
+                break;
+              //^^^^^ error: break outside of loop
+                break 'a;
+              //^^^^^^^^ error: break outside of loop
+                continue;
+              //^^^^^^^^ error: continue outside of loop
+                continue 'a;
+              //^^^^^^^^^^^ error: continue outside of loop
+        };
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn blocks_pass_through() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    'a: loop {
+        {
+            break;
+            break 'a;
+            continue;
+            continue 'a;
+        }
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn label_blocks() {
+        check_diagnostics(
+            r#"
+fn foo() {
+    'a: {
+        break;
+      //^^^^^ error: break outside of loop
+        break 'a;
+        continue;
+      //^^^^^^^^ error: continue outside of loop
+        continue 'a;
+      //^^^^^^^^^^^ error: continue outside of loop
+    }
+}
 "#,
         );
     }
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/json_is_not_rust.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/json_is_not_rust.rs
index a21db5b2cec9..3034295196b4 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/json_is_not_rust.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/json_is_not_rust.rs
@@ -137,6 +137,7 @@ pub(crate) fn json_in_items(
                                         sema.db,
                                         it,
                                         config.insert_use.prefix_kind,
+                                        config.prefer_no_std,
                                     ) {
                                         insert_use(
                                             &scope,
@@ -152,6 +153,7 @@ pub(crate) fn json_in_items(
                                         sema.db,
                                         it,
                                         config.insert_use.prefix_kind,
+                                        config.prefer_no_std,
                                     ) {
                                         insert_use(
                                             &scope,
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_fields.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_fields.rs
index edb1fc0919c2..7f140eb6a74a 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_fields.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_fields.rs
@@ -124,6 +124,7 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::MissingFields) -> Option<Vec<Ass
                         let type_path = current_module?.find_use_path(
                             ctx.sema.db,
                             item_for_path_search(ctx.sema.db, item_in_ns)?,
+                            ctx.config.prefer_no_std,
                         )?;
 
                         use_trivial_constructor(
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_match_arms.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_match_arms.rs
index 5fcaf405b14b..c24430ce6046 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_match_arms.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/missing_match_arms.rs
@@ -947,6 +947,50 @@ fn f() {
         );
     }
 
+    mod rust_unstable {
+        use super::*;
+
+        #[test]
+        fn rfc_1872_exhaustive_patterns() {
+            check_diagnostics_no_bails(
+                r"
+//- minicore: option, result
+#![feature(exhaustive_patterns)]
+enum Void {}
+fn test() {
+    match None::<!> { None => () }
+    match Result::<u8, !>::Ok(2) { Ok(_) => () }
+    match Result::<u8, Void>::Ok(2) { Ok(_) => () }
+    match (2, loop {}) {}
+    match Result::<!, !>::Ok(loop {}) {}
+    match (&loop {}) {} // https://github.com/rust-lang/rust/issues/50642#issuecomment-388234919
+    //    ^^^^^^^^^^ error: missing match arm: type `&!` is non-empty
+}",
+            );
+        }
+
+        #[test]
+        fn rfc_1872_private_uninhabitedness() {
+            check_diagnostics_no_bails(
+                r"
+//- minicore: option
+//- /lib.rs crate:lib
+#![feature(exhaustive_patterns)]
+pub struct PrivatelyUninhabited { private_field: Void }
+enum Void {}
+fn test_local(x: Option<PrivatelyUninhabited>) {
+    match x {}
+} //      ^ error: missing match arm: `None` not covered
+//- /main.rs crate:main deps:lib
+#![feature(exhaustive_patterns)]
+fn test(x: Option<lib::PrivatelyUninhabited>) {
+    match x {}
+    //    ^ error: missing match arm: `None` and `Some(_)` not covered
+}",
+            );
+        }
+    }
+
     mod false_negatives {
         //! The implementation of match checking here is a work in progress. As we roll this out, we
         //! prefer false negatives to false positives (ideally there would be no false positives). This
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/type_mismatch.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/type_mismatch.rs
index 6bf90e645b49..62c69f90baa4 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/type_mismatch.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/type_mismatch.rs
@@ -59,9 +59,6 @@ fn add_reference(
     d: &hir::TypeMismatch,
     acc: &mut Vec<Assist>,
 ) -> Option<()> {
-    let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
-    let expr_node = d.expr.value.to_node(&root);
-
     let range = ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range;
 
     let (_, mutability) = d.expected.as_reference()?;
@@ -72,7 +69,7 @@ fn add_reference(
 
     let ampersands = format!("&{}", mutability.as_keyword_for_ref());
 
-    let edit = TextEdit::insert(expr_node.syntax().text_range().start(), ampersands);
+    let edit = TextEdit::insert(range.start(), ampersands);
     let source_change =
         SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
     acc.push(fix("add_reference_here", "Add reference here", source_change, range));
@@ -314,6 +311,34 @@ fn main() {
         );
     }
 
+    #[test]
+    fn test_add_reference_to_macro_call() {
+        check_fix(
+            r#"
+macro_rules! thousand {
+    () => {
+        1000_u64
+    };
+}
+fn test(foo: &u64) {}
+fn main() {
+    test($0thousand!());
+}
+            "#,
+            r#"
+macro_rules! thousand {
+    () => {
+        1000_u64
+    };
+}
+fn test(foo: &u64) {}
+fn main() {
+    test(&thousand!());
+}
+            "#,
+        );
+    }
+
     #[test]
     fn test_add_mutable_reference_to_let_stmt() {
         check_fix(
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
index 61e63ea7a93c..ae299f058414 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
@@ -150,6 +150,7 @@ pub struct DiagnosticsConfig {
     pub expr_fill_default: ExprFillDefaultMode,
     // FIXME: We may want to include a whole `AssistConfig` here
     pub insert_use: InsertUseConfig,
+    pub prefer_no_std: bool,
 }
 
 impl DiagnosticsConfig {
@@ -170,6 +171,7 @@ impl DiagnosticsConfig {
                 group: false,
                 skip_glob_imports: false,
             },
+            prefer_no_std: false,
         }
     }
 }
diff --git a/src/tools/rust-analyzer/crates/ide-ssr/src/matching.rs b/src/tools/rust-analyzer/crates/ide-ssr/src/matching.rs
index e3a837ddcdb0..57b5ab6abda6 100644
--- a/src/tools/rust-analyzer/crates/ide-ssr/src/matching.rs
+++ b/src/tools/rust-analyzer/crates/ide-ssr/src/matching.rs
@@ -648,9 +648,10 @@ impl Match {
             .module();
         for (path, resolved_path) in &template.resolved_paths {
             if let hir::PathResolution::Def(module_def) = resolved_path.resolution {
-                let mod_path = module.find_use_path(sema.db, module_def).ok_or_else(|| {
-                    match_error!("Failed to render template path `{}` at match location")
-                })?;
+                let mod_path =
+                    module.find_use_path(sema.db, module_def, false).ok_or_else(|| {
+                        match_error!("Failed to render template path `{}` at match location")
+                    })?;
                 self.rendered_template_paths.insert(path.clone(), mod_path);
             }
         }
diff --git a/src/tools/rust-analyzer/crates/ide/src/annotations.rs b/src/tools/rust-analyzer/crates/ide/src/annotations.rs
index 210c5c7facd2..bfbe0db6e4b8 100644
--- a/src/tools/rust-analyzer/crates/ide/src/annotations.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/annotations.rs
@@ -41,6 +41,12 @@ pub struct AnnotationConfig {
     pub annotate_references: bool,
     pub annotate_method_references: bool,
     pub annotate_enum_variant_references: bool,
+    pub location: AnnotationLocation,
+}
+
+pub enum AnnotationLocation {
+    AboveName,
+    AboveWholeItem,
 }
 
 pub(crate) fn annotations(
@@ -65,10 +71,10 @@ pub(crate) fn annotations(
     visit_file_defs(&Semantics::new(db), file_id, &mut |def| {
         let range = match def {
             Definition::Const(konst) if config.annotate_references => {
-                konst.source(db).and_then(|node| name_range(db, node, file_id))
+                konst.source(db).and_then(|node| name_range(db, config, node, file_id))
             }
             Definition::Trait(trait_) if config.annotate_references || config.annotate_impls => {
-                trait_.source(db).and_then(|node| name_range(db, node, file_id))
+                trait_.source(db).and_then(|node| name_range(db, config, node, file_id))
             }
             Definition::Adt(adt) => match adt {
                 hir::Adt::Enum(enum_) => {
@@ -77,7 +83,9 @@ pub(crate) fn annotations(
                             .variants(db)
                             .into_iter()
                             .map(|variant| {
-                                variant.source(db).and_then(|node| name_range(db, node, file_id))
+                                variant
+                                    .source(db)
+                                    .and_then(|node| name_range(db, config, node, file_id))
                             })
                             .flatten()
                             .for_each(|range| {
@@ -88,14 +96,14 @@ pub(crate) fn annotations(
                             })
                     }
                     if config.annotate_references || config.annotate_impls {
-                        enum_.source(db).and_then(|node| name_range(db, node, file_id))
+                        enum_.source(db).and_then(|node| name_range(db, config, node, file_id))
                     } else {
                         None
                     }
                 }
                 _ => {
                     if config.annotate_references || config.annotate_impls {
-                        adt.source(db).and_then(|node| name_range(db, node, file_id))
+                        adt.source(db).and_then(|node| name_range(db, config, node, file_id))
                     } else {
                         None
                     }
@@ -113,6 +121,7 @@ pub(crate) fn annotations(
             annotations
                 .push(Annotation { range, kind: AnnotationKind::HasImpls { file_id, data: None } });
         }
+
         if config.annotate_references {
             annotations.push(Annotation {
                 range,
@@ -122,12 +131,18 @@ pub(crate) fn annotations(
 
         fn name_range<T: HasName>(
             db: &RootDatabase,
+            config: &AnnotationConfig,
             node: InFile<T>,
             source_file_id: FileId,
         ) -> Option<TextRange> {
             if let Some(InFile { file_id, value }) = node.original_ast_node(db) {
                 if file_id == source_file_id.into() {
-                    return value.name().map(|it| it.syntax().text_range());
+                    return match config.location {
+                        AnnotationLocation::AboveName => {
+                            value.name().map(|name| name.syntax().text_range())
+                        }
+                        AnnotationLocation::AboveWholeItem => Some(value.syntax().text_range()),
+                    };
                 }
             }
             None
@@ -188,21 +203,23 @@ mod tests {
 
     use crate::{fixture, Annotation, AnnotationConfig};
 
-    fn check(ra_fixture: &str, expect: Expect) {
+    use super::AnnotationLocation;
+
+    const DEFAULT_CONFIG: AnnotationConfig = AnnotationConfig {
+        binary_target: true,
+        annotate_runnables: true,
+        annotate_impls: true,
+        annotate_references: true,
+        annotate_method_references: true,
+        annotate_enum_variant_references: true,
+        location: AnnotationLocation::AboveName,
+    };
+
+    fn check_with_config(ra_fixture: &str, expect: Expect, config: &AnnotationConfig) {
         let (analysis, file_id) = fixture::file(ra_fixture);
 
         let annotations: Vec<Annotation> = analysis
-            .annotations(
-                &AnnotationConfig {
-                    binary_target: true,
-                    annotate_runnables: true,
-                    annotate_impls: true,
-                    annotate_references: true,
-                    annotate_method_references: true,
-                    annotate_enum_variant_references: true,
-                },
-                file_id,
-            )
+            .annotations(config, file_id)
             .unwrap()
             .into_iter()
             .map(|annotation| analysis.resolve_annotation(annotation).unwrap())
@@ -211,6 +228,10 @@ mod tests {
         expect.assert_debug_eq(&annotations);
     }
 
+    fn check(ra_fixture: &str, expect: Expect) {
+        check_with_config(ra_fixture, expect, &DEFAULT_CONFIG);
+    }
+
     #[test]
     fn const_annotations() {
         check(
@@ -786,4 +807,40 @@ m!();
             "#]],
         );
     }
+
+    #[test]
+    fn test_annotations_appear_above_whole_item_when_configured_to_do_so() {
+        check_with_config(
+            r#"
+/// This is a struct named Foo, obviously.
+#[derive(Clone)]
+struct Foo;
+"#,
+            expect![[r#"
+                [
+                    Annotation {
+                        range: 0..71,
+                        kind: HasImpls {
+                            file_id: FileId(
+                                0,
+                            ),
+                            data: Some(
+                                [],
+                            ),
+                        },
+                    },
+                    Annotation {
+                        range: 0..71,
+                        kind: HasReferences {
+                            file_id: FileId(
+                                0,
+                            ),
+                            data: None,
+                        },
+                    },
+                ]
+            "#]],
+            &AnnotationConfig { location: AnnotationLocation::AboveWholeItem, ..DEFAULT_CONFIG },
+        );
+    }
 }
diff --git a/src/tools/rust-analyzer/crates/ide/src/highlight_related.rs b/src/tools/rust-analyzer/crates/ide/src/highlight_related.rs
index f190da326e45..1bdd626f1e83 100644
--- a/src/tools/rust-analyzer/crates/ide/src/highlight_related.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/highlight_related.rs
@@ -377,6 +377,7 @@ mod tests {
                         match it {
                             ReferenceCategory::Read => "read",
                             ReferenceCategory::Write => "write",
+                            ReferenceCategory::Import => "import",
                         }
                         .to_string()
                     }),
@@ -423,12 +424,12 @@ struct Foo;
         check(
             r#"
 use crate$0;
-  //^^^^^
+  //^^^^^ import
 use self;
-  //^^^^
+  //^^^^ import
 mod __ {
     use super;
-      //^^^^^
+      //^^^^^ import
 }
 "#,
         );
@@ -436,7 +437,7 @@ mod __ {
             r#"
 //- /main.rs crate:main deps:lib
 use lib$0;
-  //^^^
+  //^^^ import
 //- /lib.rs crate:lib
 "#,
         );
@@ -450,7 +451,7 @@ use lib$0;
 mod foo;
 //- /foo.rs
 use self$0;
- // ^^^^
+ // ^^^^ import
 "#,
         );
     }
diff --git a/src/tools/rust-analyzer/crates/ide/src/hover/render.rs b/src/tools/rust-analyzer/crates/ide/src/hover/render.rs
index d52adaee535f..c5c50d88dd28 100644
--- a/src/tools/rust-analyzer/crates/ide/src/hover/render.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/hover/render.rs
@@ -2,12 +2,13 @@
 use std::fmt::Display;
 
 use either::Either;
-use hir::{AsAssocItem, AttributeTemplate, HasAttrs, HirDisplay, Semantics, TypeInfo};
+use hir::{AsAssocItem, AttributeTemplate, HasAttrs, HasSource, HirDisplay, Semantics, TypeInfo};
 use ide_db::{
     base_db::SourceDatabase,
     defs::Definition,
     famous_defs::FamousDefs,
     generated::lints::{CLIPPY_LINTS, DEFAULT_LINTS, FEATURES},
+    syntax_helpers::insert_whitespace_into_node,
     RootDatabase,
 };
 use itertools::Itertools;
@@ -350,10 +351,24 @@ pub(super) fn definition(
             let body = it.eval(db);
             match body {
                 Ok(x) => Some(format!("{}", x)),
-                Err(_) => it.value(db).map(|x| format!("{}", x)),
+                Err(_) => {
+                    let source = it.source(db)?;
+                    let mut body = source.value.body()?.syntax().clone();
+                    if source.file_id.is_macro() {
+                        body = insert_whitespace_into_node::insert_ws_into(body);
+                    }
+                    Some(body.to_string())
+                }
             }
         }),
-        Definition::Static(it) => label_value_and_docs(db, it, |it| it.value(db)),
+        Definition::Static(it) => label_value_and_docs(db, it, |it| {
+            let source = it.source(db)?;
+            let mut body = source.value.body()?.syntax().clone();
+            if source.file_id.is_macro() {
+                body = insert_whitespace_into_node::insert_ws_into(body);
+            }
+            Some(body.to_string())
+        }),
         Definition::Trait(it) => label_and_docs(db, it),
         Definition::TypeAlias(it) => label_and_docs(db, it),
         Definition::BuiltinType(it) => {
diff --git a/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs b/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs
index 685eb4521ebd..4b8b47783d12 100644
--- a/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs
@@ -5113,3 +5113,61 @@ fn f() {
         "#]],
     );
 }
+
+#[test]
+fn static_const_macro_expanded_body() {
+    check(
+        r#"
+macro_rules! m {
+    () => {
+        pub const V: i8 = {
+            let e = 123;
+            f(e) // Prevent const eval from evaluating this constant, we want to print the body's code.
+        };
+    };
+}
+m!();
+fn main() { $0V; }
+"#,
+        expect![[r#"
+            *V*
+
+            ```rust
+            test
+            ```
+
+            ```rust
+            pub const V: i8 = {
+              let e = 123;
+              f(e)
+            }
+            ```
+        "#]],
+    );
+    check(
+        r#"
+macro_rules! m {
+    () => {
+        pub static V: i8 = {
+            let e = 123;
+        };
+    };
+}
+m!();
+fn main() { $0V; }
+"#,
+        expect![[r#"
+            *V*
+
+            ```rust
+            test
+            ```
+
+            ```rust
+            pub static V: i8 = {
+              let e = 123;
+            }
+            ```
+        "#]],
+    );
+}
diff --git a/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs b/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs
index ed19784d1fa4..93fcd7cad7a1 100644
--- a/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs
@@ -1,3 +1,5 @@
+use std::fmt;
+
 use either::Either;
 use hir::{known, Callable, HasVisibility, HirDisplay, Mutability, Semantics, TypeInfo};
 use ide_db::{
@@ -69,7 +71,7 @@ pub enum InlayKind {
 pub struct InlayHint {
     pub range: TextRange,
     pub kind: InlayKind,
-    pub label: String,
+    pub label: InlayHintLabel,
     pub tooltip: Option<InlayTooltip>,
 }
 
@@ -80,6 +82,83 @@ pub enum InlayTooltip {
     HoverOffset(FileId, TextSize),
 }
 
+pub struct InlayHintLabel {
+    pub parts: Vec<InlayHintLabelPart>,
+}
+
+impl InlayHintLabel {
+    pub fn as_simple_str(&self) -> Option<&str> {
+        match &*self.parts {
+            [part] => part.as_simple_str(),
+            _ => None,
+        }
+    }
+
+    pub fn prepend_str(&mut self, s: &str) {
+        match &mut *self.parts {
+            [part, ..] if part.as_simple_str().is_some() => part.text = format!("{s}{}", part.text),
+            _ => self.parts.insert(0, InlayHintLabelPart { text: s.into(), linked_location: None }),
+        }
+    }
+
+    pub fn append_str(&mut self, s: &str) {
+        match &mut *self.parts {
+            [.., part] if part.as_simple_str().is_some() => part.text.push_str(s),
+            _ => self.parts.push(InlayHintLabelPart { text: s.into(), linked_location: None }),
+        }
+    }
+}
+
+impl From<String> for InlayHintLabel {
+    fn from(s: String) -> Self {
+        Self { parts: vec![InlayHintLabelPart { text: s, linked_location: None }] }
+    }
+}
+
+impl fmt::Display for InlayHintLabel {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.parts.iter().map(|part| &part.text).format(""))
+    }
+}
+
+impl fmt::Debug for InlayHintLabel {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_list().entries(&self.parts).finish()
+    }
+}
+
+pub struct InlayHintLabelPart {
+    pub text: String,
+    /// Source location represented by this label part. The client will use this to fetch the part's
+    /// hover tooltip, and Ctrl+Clicking the label part will navigate to the definition the location
+    /// refers to (not necessarily the location itself).
+    /// When setting this, no tooltip must be set on the containing hint, or VS Code will display
+    /// them both.
+    pub linked_location: Option<FileRange>,
+}
+
+impl InlayHintLabelPart {
+    pub fn as_simple_str(&self) -> Option<&str> {
+        match self {
+            Self { text, linked_location: None } => Some(text),
+            _ => None,
+        }
+    }
+}
+
+impl fmt::Debug for InlayHintLabelPart {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.as_simple_str() {
+            Some(string) => string.fmt(f),
+            None => f
+                .debug_struct("InlayHintLabelPart")
+                .field("text", &self.text)
+                .field("linked_location", &self.linked_location)
+                .finish(),
+        }
+    }
+}
+
 // Feature: Inlay Hints
 //
 // rust-analyzer shows additional information inline with the source code.
@@ -192,10 +271,10 @@ fn closing_brace_hints(
 ) -> Option<()> {
     let min_lines = config.closing_brace_hints_min_lines?;
 
-    let name = |it: ast::Name| it.syntax().text_range().start();
+    let name = |it: ast::Name| it.syntax().text_range();
 
     let mut closing_token;
-    let (label, name_offset) = if let Some(item_list) = ast::AssocItemList::cast(node.clone()) {
+    let (label, name_range) = if let Some(item_list) = ast::AssocItemList::cast(node.clone()) {
         closing_token = item_list.r_curly_token()?;
 
         let parent = item_list.syntax().parent()?;
@@ -205,11 +284,11 @@ fn closing_brace_hints(
                     let imp = sema.to_def(&imp)?;
                     let ty = imp.self_ty(sema.db);
                     let trait_ = imp.trait_(sema.db);
-
-                    (match trait_ {
+                    let hint_text = match trait_ {
                         Some(tr) => format!("impl {} for {}", tr.name(sema.db), ty.display_truncated(sema.db, config.max_length)),
                         None => format!("impl {}", ty.display_truncated(sema.db, config.max_length)),
-                    }, None)
+                    };
+                    (hint_text, None)
                 },
                 ast::Trait(tr) => {
                     (format!("trait {}", tr.name()?), tr.name().map(name))
@@ -253,7 +332,7 @@ fn closing_brace_hints(
 
         (
             format!("{}!", mac.path()?),
-            mac.path().and_then(|it| it.segment()).map(|it| it.syntax().text_range().start()),
+            mac.path().and_then(|it| it.segment()).map(|it| it.syntax().text_range()),
         )
     } else {
         return None;
@@ -278,11 +357,12 @@ fn closing_brace_hints(
         return None;
     }
 
+    let linked_location = name_range.map(|range| FileRange { file_id, range });
     acc.push(InlayHint {
         range: closing_token.text_range(),
         kind: InlayKind::ClosingBraceHint,
-        label,
-        tooltip: name_offset.map(|it| InlayTooltip::HoverOffset(file_id, it)),
+        label: InlayHintLabel { parts: vec![InlayHintLabelPart { text: label, linked_location }] },
+        tooltip: None, // provided by label part location
     });
 
     None
@@ -311,7 +391,7 @@ fn implicit_static_hints(
             acc.push(InlayHint {
                 range: t.text_range(),
                 kind: InlayKind::LifetimeHint,
-                label: "'static".to_owned(),
+                label: "'static".to_owned().into(),
                 tooltip: Some(InlayTooltip::String("Elided static lifetime".into())),
             });
         }
@@ -329,10 +409,10 @@ fn fn_lifetime_fn_hints(
         return None;
     }
 
-    let mk_lt_hint = |t: SyntaxToken, label| InlayHint {
+    let mk_lt_hint = |t: SyntaxToken, label: String| InlayHint {
         range: t.text_range(),
         kind: InlayKind::LifetimeHint,
-        label,
+        label: label.into(),
         tooltip: Some(InlayTooltip::String("Elided lifetime".into())),
     };
 
@@ -486,7 +566,8 @@ fn fn_lifetime_fn_hints(
                     "{}{}",
                     allocated_lifetimes.iter().format(", "),
                     if is_empty { "" } else { ", " }
-                ),
+                )
+                .into(),
                 tooltip: Some(InlayTooltip::String("Elided lifetimes".into())),
             });
         }
@@ -535,7 +616,8 @@ fn closure_ret_hints(
         range: param_list.syntax().text_range(),
         kind: InlayKind::ClosureReturnTypeHint,
         label: hint_iterator(sema, &famous_defs, config, &ty)
-            .unwrap_or_else(|| ty.display_truncated(sema.db, config.max_length).to_string()),
+            .unwrap_or_else(|| ty.display_truncated(sema.db, config.max_length).to_string())
+            .into(),
         tooltip: Some(InlayTooltip::HoverRanged(file_id, param_list.syntax().text_range())),
     });
     Some(())
@@ -562,7 +644,7 @@ fn reborrow_hints(
     acc.push(InlayHint {
         range: expr.syntax().text_range(),
         kind: InlayKind::ImplicitReborrowHint,
-        label: label.to_string(),
+        label: label.to_string().into(),
         tooltip: Some(InlayTooltip::String("Compiler inserted reborrow".into())),
     });
     Some(())
@@ -620,9 +702,9 @@ fn chaining_hints(
             acc.push(InlayHint {
                 range: expr.syntax().text_range(),
                 kind: InlayKind::ChainingHint,
-                label: hint_iterator(sema, &famous_defs, config, &ty).unwrap_or_else(|| {
-                    ty.display_truncated(sema.db, config.max_length).to_string()
-                }),
+                label: hint_iterator(sema, &famous_defs, config, &ty)
+                    .unwrap_or_else(|| ty.display_truncated(sema.db, config.max_length).to_string())
+                    .into(),
                 tooltip: Some(InlayTooltip::HoverRanged(file_id, expr.syntax().text_range())),
             });
         }
@@ -674,7 +756,7 @@ fn param_name_hints(
             InlayHint {
                 range,
                 kind: InlayKind::ParameterHint,
-                label: param_name,
+                label: param_name.into(),
                 tooltip: tooltip.map(|it| InlayTooltip::HoverOffset(it.file_id, it.range.start())),
             }
         });
@@ -705,7 +787,7 @@ fn binding_mode_hints(
         acc.push(InlayHint {
             range,
             kind: InlayKind::BindingModeHint,
-            label: r.to_string(),
+            label: r.to_string().into(),
             tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
         });
     });
@@ -720,7 +802,7 @@ fn binding_mode_hints(
             acc.push(InlayHint {
                 range,
                 kind: InlayKind::BindingModeHint,
-                label: bm.to_string(),
+                label: bm.to_string().into(),
                 tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
             });
         }
@@ -772,7 +854,7 @@ fn bind_pat_hints(
             None => pat.syntax().text_range(),
         },
         kind: InlayKind::TypeHint,
-        label,
+        label: label.into(),
         tooltip: pat
             .name()
             .map(|it| it.syntax().text_range())
@@ -1605,6 +1687,74 @@ fn main() {
         );
     }
 
+    #[test]
+    fn iterator_hint_regression_issue_12674() {
+        // Ensure we don't crash while solving the projection type of iterators.
+        check_expect(
+            InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
+            r#"
+//- minicore: iterators
+struct S<T>(T);
+impl<T> S<T> {
+    fn iter(&self) -> Iter<'_, T> { loop {} }
+}
+struct Iter<'a, T: 'a>(&'a T);
+impl<'a, T> Iterator for Iter<'a, T> {
+    type Item = &'a T;
+    fn next(&mut self) -> Option<Self::Item> { loop {} }
+}
+struct Container<'a> {
+    elements: S<&'a str>,
+}
+struct SliceIter<'a, T>(&'a T);
+impl<'a, T> Iterator for SliceIter<'a, T> {
+    type Item = &'a T;
+    fn next(&mut self) -> Option<Self::Item> { loop {} }
+}
+
+fn main(a: SliceIter<'_, Container>) {
+    a
+    .filter_map(|c| Some(c.elements.iter().filter_map(|v| Some(v))))
+    .map(|e| e);
+}
+            "#,
+            expect![[r#"
+                [
+                    InlayHint {
+                        range: 484..554,
+                        kind: ChainingHint,
+                        label: [
+                            "impl Iterator<Item = impl Iterator<Item = &&str>>",
+                        ],
+                        tooltip: Some(
+                            HoverRanged(
+                                FileId(
+                                    0,
+                                ),
+                                484..554,
+                            ),
+                        ),
+                    },
+                    InlayHint {
+                        range: 484..485,
+                        kind: ChainingHint,
+                        label: [
+                            "SliceIter<Container>",
+                        ],
+                        tooltip: Some(
+                            HoverRanged(
+                                FileId(
+                                    0,
+                                ),
+                                484..485,
+                            ),
+                        ),
+                    },
+                ]
+            "#]],
+        );
+    }
+
     #[test]
     fn infer_call_method_return_associated_types_with_generic() {
         check_types(
@@ -1910,7 +2060,7 @@ impl<T> Vec<T> {
 pub struct Box<T> {}
 
 trait Display {}
-trait Sync {}
+auto trait Sync {}
 
 fn main() {
     // The block expression wrapping disables the constructor hint hiding logic
@@ -2223,7 +2373,9 @@ fn main() {
                     InlayHint {
                         range: 147..172,
                         kind: ChainingHint,
-                        label: "B",
+                        label: [
+                            "B",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2236,7 +2388,9 @@ fn main() {
                     InlayHint {
                         range: 147..154,
                         kind: ChainingHint,
-                        label: "A",
+                        label: [
+                            "A",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2294,7 +2448,9 @@ fn main() {
                     InlayHint {
                         range: 143..190,
                         kind: ChainingHint,
-                        label: "C",
+                        label: [
+                            "C",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2307,7 +2463,9 @@ fn main() {
                     InlayHint {
                         range: 143..179,
                         kind: ChainingHint,
-                        label: "B",
+                        label: [
+                            "B",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2350,7 +2508,9 @@ fn main() {
                     InlayHint {
                         range: 246..283,
                         kind: ChainingHint,
-                        label: "B<X<i32, bool>>",
+                        label: [
+                            "B<X<i32, bool>>",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2363,7 +2523,9 @@ fn main() {
                     InlayHint {
                         range: 246..265,
                         kind: ChainingHint,
-                        label: "A<X<i32, bool>>",
+                        label: [
+                            "A<X<i32, bool>>",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2408,7 +2570,9 @@ fn main() {
                     InlayHint {
                         range: 174..241,
                         kind: ChainingHint,
-                        label: "impl Iterator<Item = ()>",
+                        label: [
+                            "impl Iterator<Item = ()>",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2421,7 +2585,9 @@ fn main() {
                     InlayHint {
                         range: 174..224,
                         kind: ChainingHint,
-                        label: "impl Iterator<Item = ()>",
+                        label: [
+                            "impl Iterator<Item = ()>",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2434,7 +2600,9 @@ fn main() {
                     InlayHint {
                         range: 174..206,
                         kind: ChainingHint,
-                        label: "impl Iterator<Item = ()>",
+                        label: [
+                            "impl Iterator<Item = ()>",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2447,7 +2615,9 @@ fn main() {
                     InlayHint {
                         range: 174..189,
                         kind: ChainingHint,
-                        label: "&mut MyIter",
+                        label: [
+                            "&mut MyIter",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2489,7 +2659,9 @@ fn main() {
                     InlayHint {
                         range: 124..130,
                         kind: TypeHint,
-                        label: "Struct",
+                        label: [
+                            "Struct",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2502,7 +2674,9 @@ fn main() {
                     InlayHint {
                         range: 145..185,
                         kind: ChainingHint,
-                        label: "Struct",
+                        label: [
+                            "Struct",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2515,7 +2689,9 @@ fn main() {
                     InlayHint {
                         range: 145..168,
                         kind: ChainingHint,
-                        label: "Struct",
+                        label: [
+                            "Struct",
+                        ],
                         tooltip: Some(
                             HoverRanged(
                                 FileId(
@@ -2528,7 +2704,9 @@ fn main() {
                     InlayHint {
                         range: 222..228,
                         kind: ParameterHint,
-                        label: "self",
+                        label: [
+                            "self",
+                        ],
                         tooltip: Some(
                             HoverOffset(
                                 FileId(
diff --git a/src/tools/rust-analyzer/crates/ide/src/lib.rs b/src/tools/rust-analyzer/crates/ide/src/lib.rs
index d61d69a090b3..c1ef25b592b1 100644
--- a/src/tools/rust-analyzer/crates/ide/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/lib.rs
@@ -74,7 +74,7 @@ use syntax::SourceFile;
 use crate::navigation_target::{ToNav, TryToNav};
 
 pub use crate::{
-    annotations::{Annotation, AnnotationConfig, AnnotationKind},
+    annotations::{Annotation, AnnotationConfig, AnnotationKind, AnnotationLocation},
     call_hierarchy::CallItem,
     expand_macro::ExpandedMacro,
     file_structure::{StructureNode, StructureNodeKind},
@@ -82,8 +82,8 @@ pub use crate::{
     highlight_related::{HighlightRelatedConfig, HighlightedRange},
     hover::{HoverAction, HoverConfig, HoverDocFormat, HoverGotoTypeData, HoverResult},
     inlay_hints::{
-        ClosureReturnTypeHints, InlayHint, InlayHintsConfig, InlayKind, InlayTooltip,
-        LifetimeElisionHints, ReborrowHints,
+        ClosureReturnTypeHints, InlayHint, InlayHintLabel, InlayHintsConfig, InlayKind,
+        InlayTooltip, LifetimeElisionHints, ReborrowHints,
     },
     join_lines::JoinLinesConfig,
     markup::Markup,
diff --git a/src/tools/rust-analyzer/crates/ide/src/references.rs b/src/tools/rust-analyzer/crates/ide/src/references.rs
index 99614b645e48..e942413c1105 100644
--- a/src/tools/rust-analyzer/crates/ide/src/references.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/references.rs
@@ -742,7 +742,7 @@ pub struct Foo {
             expect![[r#"
                 foo Module FileId(0) 0..8 4..7
 
-                FileId(0) 14..17
+                FileId(0) 14..17 Import
             "#]],
         );
     }
@@ -760,7 +760,7 @@ use self$0;
             expect![[r#"
                 foo Module FileId(0) 0..8 4..7
 
-                FileId(1) 4..8
+                FileId(1) 4..8 Import
             "#]],
         );
     }
@@ -775,7 +775,7 @@ use self$0;
             expect![[r#"
                 Module FileId(0) 0..10
 
-                FileId(0) 4..8
+                FileId(0) 4..8 Import
             "#]],
         );
     }
@@ -803,7 +803,7 @@ pub(super) struct Foo$0 {
             expect![[r#"
                 Foo Struct FileId(2) 0..41 18..21
 
-                FileId(1) 20..23
+                FileId(1) 20..23 Import
                 FileId(1) 47..50
             "#]],
         );
@@ -966,7 +966,7 @@ fn g() { f(); }
             expect![[r#"
                 f Function FileId(0) 22..31 25..26
 
-                FileId(1) 11..12
+                FileId(1) 11..12 Import
                 FileId(1) 24..25
             "#]],
         );
@@ -1424,9 +1424,9 @@ pub use level1::Foo;
             expect![[r#"
                 Foo Struct FileId(0) 0..15 11..14
 
-                FileId(1) 16..19
-                FileId(2) 16..19
-                FileId(3) 16..19
+                FileId(1) 16..19 Import
+                FileId(2) 16..19 Import
+                FileId(3) 16..19 Import
             "#]],
         );
     }
@@ -1454,7 +1454,7 @@ lib::foo!();
             expect![[r#"
                 foo Macro FileId(1) 0..61 29..32
 
-                FileId(0) 46..49
+                FileId(0) 46..49 Import
                 FileId(2) 0..3
                 FileId(3) 5..8
             "#]],
@@ -1617,7 +1617,7 @@ struct Foo;
             expect![[r#"
                 derive_identity Derive FileId(2) 1..107 45..60
 
-                FileId(0) 17..31
+                FileId(0) 17..31 Import
                 FileId(0) 56..70
             "#]],
         );
diff --git a/src/tools/rust-analyzer/crates/mbe/src/expander/matcher.rs b/src/tools/rust-analyzer/crates/mbe/src/expander/matcher.rs
index c1aa14d6b7e7..139a8cb8cbe5 100644
--- a/src/tools/rust-analyzer/crates/mbe/src/expander/matcher.rs
+++ b/src/tools/rust-analyzer/crates/mbe/src/expander/matcher.rs
@@ -203,17 +203,16 @@ impl BindingsBuilder {
     }
 
     fn build(self, idx: &BindingsIdx) -> Bindings {
-        let mut bindings = Bindings::default();
-        self.build_inner(&mut bindings, &self.nodes[idx.0]);
-        bindings
+        self.build_inner(&self.nodes[idx.0])
     }
 
-    fn build_inner(&self, bindings: &mut Bindings, link_nodes: &[LinkNode<Rc<BindingKind>>]) {
+    fn build_inner(&self, link_nodes: &[LinkNode<Rc<BindingKind>>]) -> Bindings {
+        let mut bindings = Bindings::default();
         let mut nodes = Vec::new();
         self.collect_nodes(link_nodes, &mut nodes);
 
         for cmd in nodes {
-            match &**cmd {
+            match cmd {
                 BindingKind::Empty(name) => {
                     bindings.push_empty(name);
                 }
@@ -246,13 +245,15 @@ impl BindingsBuilder {
                 }
             }
         }
+
+        bindings
     }
 
     fn collect_nested_ref<'a>(
         &'a self,
         id: usize,
         len: usize,
-        nested_refs: &mut Vec<&'a Vec<LinkNode<Rc<BindingKind>>>>,
+        nested_refs: &mut Vec<&'a [LinkNode<Rc<BindingKind>>]>,
     ) {
         self.nested[id].iter().take(len).for_each(|it| match it {
             LinkNode::Node(id) => nested_refs.push(&self.nodes[*id]),
@@ -262,26 +263,16 @@ impl BindingsBuilder {
 
     fn collect_nested(&self, idx: usize, nested_idx: usize, nested: &mut Vec<Bindings>) {
         let last = &self.nodes[idx];
-        let mut nested_refs = Vec::new();
+        let mut nested_refs: Vec<&[_]> = Vec::new();
         self.nested[nested_idx].iter().for_each(|it| match *it {
             LinkNode::Node(idx) => nested_refs.push(&self.nodes[idx]),
             LinkNode::Parent { idx, len } => self.collect_nested_ref(idx, len, &mut nested_refs),
         });
         nested_refs.push(last);
-
-        nested_refs.into_iter().for_each(|iter| {
-            let mut child_bindings = Bindings::default();
-            self.build_inner(&mut child_bindings, iter);
-            nested.push(child_bindings)
-        })
+        nested.extend(nested_refs.into_iter().map(|iter| self.build_inner(iter)));
     }
 
-    fn collect_nodes_ref<'a>(
-        &'a self,
-        id: usize,
-        len: usize,
-        nodes: &mut Vec<&'a Rc<BindingKind>>,
-    ) {
+    fn collect_nodes_ref<'a>(&'a self, id: usize, len: usize, nodes: &mut Vec<&'a BindingKind>) {
         self.nodes[id].iter().take(len).for_each(|it| match it {
             LinkNode::Node(it) => nodes.push(it),
             LinkNode::Parent { idx, len } => self.collect_nodes_ref(*idx, *len, nodes),
@@ -291,7 +282,7 @@ impl BindingsBuilder {
     fn collect_nodes<'a>(
         &'a self,
         link_nodes: &'a [LinkNode<Rc<BindingKind>>],
-        nodes: &mut Vec<&'a Rc<BindingKind>>,
+        nodes: &mut Vec<&'a BindingKind>,
     ) {
         link_nodes.iter().for_each(|it| match it {
             LinkNode::Node(it) => nodes.push(it),
@@ -386,10 +377,10 @@ fn match_loop_inner<'t>(
         let op = match item.dot.peek() {
             None => {
                 // We are at or past the end of the matcher of `item`.
-                if item.up.is_some() {
+                if let Some(up) = &item.up {
                     if item.sep_parsed.is_none() {
                         // Get the `up` matcher
-                        let mut new_pos = *item.up.clone().unwrap();
+                        let mut new_pos = (**up).clone();
                         new_pos.bindings = bindings_builder.copy(&new_pos.bindings);
                         // Add matches from this repetition to the `matches` of `up`
                         bindings_builder.push_nested(&mut new_pos.bindings, &item.bindings);
@@ -402,7 +393,7 @@ fn match_loop_inner<'t>(
 
                     // Check if we need a separator.
                     // We check the separator one by one
-                    let sep_idx = *item.sep_parsed.as_ref().unwrap_or(&0);
+                    let sep_idx = item.sep_parsed.unwrap_or(0);
                     let sep_len = item.sep.as_ref().map_or(0, Separator::tt_count);
                     if item.sep.is_some() && sep_idx != sep_len {
                         let sep = item.sep.as_ref().unwrap();
diff --git a/src/tools/rust-analyzer/crates/parser/src/grammar/paths.rs b/src/tools/rust-analyzer/crates/parser/src/grammar/paths.rs
index 8de5d33a1936..5dc9c6c82a14 100644
--- a/src/tools/rust-analyzer/crates/parser/src/grammar/paths.rs
+++ b/src/tools/rust-analyzer/crates/parser/src/grammar/paths.rs
@@ -118,6 +118,11 @@ fn opt_path_type_args(p: &mut Parser<'_>, mode: Mode) {
     match mode {
         Mode::Use => {}
         Mode::Type => {
+            // test typepathfn_with_coloncolon
+            // type F = Start::(Middle) -> (Middle)::End;
+            if p.at(T![::]) && p.nth_at(2, T!['(']) {
+                p.bump(T![::]);
+            }
             // test path_fn_trait_args
             // type F = Box<Fn(i32) -> ()>;
             if p.at(T!['(']) {
diff --git a/src/tools/rust-analyzer/crates/parser/src/syntax_kind/generated.rs b/src/tools/rust-analyzer/crates/parser/src/syntax_kind/generated.rs
index 628fa745e752..c84f45f1f8e4 100644
--- a/src/tools/rust-analyzer/crates/parser/src/syntax_kind/generated.rs
+++ b/src/tools/rust-analyzer/crates/parser/src/syntax_kind/generated.rs
@@ -262,33 +262,117 @@ pub enum SyntaxKind {
 use self::SyntaxKind::*;
 impl SyntaxKind {
     pub fn is_keyword(self) -> bool {
-        match self {
-            AS_KW | ASYNC_KW | AWAIT_KW | BOX_KW | BREAK_KW | CONST_KW | CONTINUE_KW | CRATE_KW
-            | DYN_KW | ELSE_KW | ENUM_KW | EXTERN_KW | FALSE_KW | FN_KW | FOR_KW | IF_KW
-            | IMPL_KW | IN_KW | LET_KW | LOOP_KW | MACRO_KW | MATCH_KW | MOD_KW | MOVE_KW
-            | MUT_KW | PUB_KW | REF_KW | RETURN_KW | SELF_KW | SELF_TYPE_KW | STATIC_KW
-            | STRUCT_KW | SUPER_KW | TRAIT_KW | TRUE_KW | TRY_KW | TYPE_KW | UNSAFE_KW | USE_KW
-            | WHERE_KW | WHILE_KW | YIELD_KW | AUTO_KW | DEFAULT_KW | EXISTENTIAL_KW | UNION_KW
-            | RAW_KW | MACRO_RULES_KW => true,
-            _ => false,
-        }
+        matches!(
+            self,
+            AS_KW
+                | ASYNC_KW
+                | AWAIT_KW
+                | BOX_KW
+                | BREAK_KW
+                | CONST_KW
+                | CONTINUE_KW
+                | CRATE_KW
+                | DYN_KW
+                | ELSE_KW
+                | ENUM_KW
+                | EXTERN_KW
+                | FALSE_KW
+                | FN_KW
+                | FOR_KW
+                | IF_KW
+                | IMPL_KW
+                | IN_KW
+                | LET_KW
+                | LOOP_KW
+                | MACRO_KW
+                | MATCH_KW
+                | MOD_KW
+                | MOVE_KW
+                | MUT_KW
+                | PUB_KW
+                | REF_KW
+                | RETURN_KW
+                | SELF_KW
+                | SELF_TYPE_KW
+                | STATIC_KW
+                | STRUCT_KW
+                | SUPER_KW
+                | TRAIT_KW
+                | TRUE_KW
+                | TRY_KW
+                | TYPE_KW
+                | UNSAFE_KW
+                | USE_KW
+                | WHERE_KW
+                | WHILE_KW
+                | YIELD_KW
+                | AUTO_KW
+                | DEFAULT_KW
+                | EXISTENTIAL_KW
+                | UNION_KW
+                | RAW_KW
+                | MACRO_RULES_KW
+        )
     }
     pub fn is_punct(self) -> bool {
-        match self {
-            SEMICOLON | COMMA | L_PAREN | R_PAREN | L_CURLY | R_CURLY | L_BRACK | R_BRACK
-            | L_ANGLE | R_ANGLE | AT | POUND | TILDE | QUESTION | DOLLAR | AMP | PIPE | PLUS
-            | STAR | SLASH | CARET | PERCENT | UNDERSCORE | DOT | DOT2 | DOT3 | DOT2EQ | COLON
-            | COLON2 | EQ | EQ2 | FAT_ARROW | BANG | NEQ | MINUS | THIN_ARROW | LTEQ | GTEQ
-            | PLUSEQ | MINUSEQ | PIPEEQ | AMPEQ | CARETEQ | SLASHEQ | STAREQ | PERCENTEQ | AMP2
-            | PIPE2 | SHL | SHR | SHLEQ | SHREQ => true,
-            _ => false,
-        }
+        matches!(
+            self,
+            SEMICOLON
+                | COMMA
+                | L_PAREN
+                | R_PAREN
+                | L_CURLY
+                | R_CURLY
+                | L_BRACK
+                | R_BRACK
+                | L_ANGLE
+                | R_ANGLE
+                | AT
+                | POUND
+                | TILDE
+                | QUESTION
+                | DOLLAR
+                | AMP
+                | PIPE
+                | PLUS
+                | STAR
+                | SLASH
+                | CARET
+                | PERCENT
+                | UNDERSCORE
+                | DOT
+                | DOT2
+                | DOT3
+                | DOT2EQ
+                | COLON
+                | COLON2
+                | EQ
+                | EQ2
+                | FAT_ARROW
+                | BANG
+                | NEQ
+                | MINUS
+                | THIN_ARROW
+                | LTEQ
+                | GTEQ
+                | PLUSEQ
+                | MINUSEQ
+                | PIPEEQ
+                | AMPEQ
+                | CARETEQ
+                | SLASHEQ
+                | STAREQ
+                | PERCENTEQ
+                | AMP2
+                | PIPE2
+                | SHL
+                | SHR
+                | SHLEQ
+                | SHREQ
+        )
     }
     pub fn is_literal(self) -> bool {
-        match self {
-            INT_NUMBER | FLOAT_NUMBER | CHAR | BYTE | STRING | BYTE_STRING => true,
-            _ => false,
-        }
+        matches!(self, INT_NUMBER | FLOAT_NUMBER | CHAR | BYTE | STRING | BYTE_STRING)
     }
     pub fn from_keyword(ident: &str) -> Option<SyntaxKind> {
         let kw = match ident {
diff --git a/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast
new file mode 100644
index 000000000000..b47a5a5c1470
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast
@@ -0,0 +1,43 @@
+SOURCE_FILE
+  TYPE_ALIAS
+    TYPE_KW "type"
+    WHITESPACE " "
+    NAME
+      IDENT "F"
+    WHITESPACE " "
+    EQ "="
+    WHITESPACE " "
+    PATH_TYPE
+      PATH
+        PATH
+          PATH_SEGMENT
+            NAME_REF
+              IDENT "Start"
+            COLON2 "::"
+            PARAM_LIST
+              L_PAREN "("
+              PARAM
+                PATH_TYPE
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "Middle"
+              R_PAREN ")"
+            WHITESPACE " "
+            RET_TYPE
+              THIN_ARROW "->"
+              WHITESPACE " "
+              PAREN_TYPE
+                L_PAREN "("
+                PATH_TYPE
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "Middle"
+                R_PAREN ")"
+        COLON2 "::"
+        PATH_SEGMENT
+          NAME_REF
+            IDENT "End"
+    SEMICOLON ";"
+  WHITESPACE "\n"
diff --git a/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs
new file mode 100644
index 000000000000..8efd93a7ff68
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs
@@ -0,0 +1 @@
+type F = Start::(Middle) -> (Middle)::End;
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_sysroot/ra_server.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_sysroot/ra_server.rs
index 52eb7ce17d6a..e4e43e97dde8 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_sysroot/ra_server.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_sysroot/ra_server.rs
@@ -37,23 +37,6 @@ pub struct SourceFile {
 type Level = super::proc_macro::Level;
 type LineColumn = super::proc_macro::LineColumn;
 
-/// A structure representing a diagnostic message and associated children
-/// messages.
-#[derive(Clone, Debug)]
-pub struct Diagnostic {
-    level: Level,
-    message: String,
-    spans: Vec<Span>,
-    children: Vec<Diagnostic>,
-}
-
-impl Diagnostic {
-    /// Creates a new diagnostic with the given `level` and `message`.
-    pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
-        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
-    }
-}
-
 pub struct FreeFunctions;
 
 #[derive(Default)]
@@ -65,8 +48,6 @@ impl server::Types for RustAnalyzer {
     type FreeFunctions = FreeFunctions;
     type TokenStream = TokenStream;
     type SourceFile = SourceFile;
-    type MultiSpan = Vec<Span>;
-    type Diagnostic = Diagnostic;
     type Span = Span;
     type Symbol = Symbol;
 }
@@ -90,6 +71,10 @@ impl server::FreeFunctions for RustAnalyzer {
             span: tt::TokenId::unspecified(),
         })
     }
+
+    fn emit_diagnostic(&mut self, _: bridge::Diagnostic<Self::Span>) {
+        // FIXME handle diagnostic
+    }
 }
 
 impl server::TokenStream for RustAnalyzer {
@@ -282,30 +267,6 @@ impl server::SourceFile for RustAnalyzer {
     }
 }
 
-impl server::Diagnostic for RustAnalyzer {
-    fn new(&mut self, level: Level, msg: &str, spans: Self::MultiSpan) -> Self::Diagnostic {
-        let mut diag = Diagnostic::new(level, msg);
-        diag.spans = spans;
-        diag
-    }
-
-    fn sub(
-        &mut self,
-        _diag: &mut Self::Diagnostic,
-        _level: Level,
-        _msg: &str,
-        _spans: Self::MultiSpan,
-    ) {
-        // FIXME handle diagnostic
-        //
-    }
-
-    fn emit(&mut self, _diag: Self::Diagnostic) {
-        // FIXME handle diagnostic
-        // diag.emit()
-    }
-}
-
 impl server::Span for RustAnalyzer {
     fn debug(&mut self, span: Self::Span) -> String {
         format!("{:?}", span.0)
@@ -372,18 +333,6 @@ impl server::Span for RustAnalyzer {
     }
 }
 
-impl server::MultiSpan for RustAnalyzer {
-    fn new(&mut self) -> Self::MultiSpan {
-        // FIXME handle span
-        vec![]
-    }
-
-    fn push(&mut self, other: &mut Self::MultiSpan, span: Self::Span) {
-        //TODP
-        other.push(span)
-    }
-}
-
 impl server::Symbol for RustAnalyzer {
     fn normalize_and_validate_ident(&mut self, string: &str) -> Result<Self::Symbol, ()> {
         // FIXME: nfc-normalize and validate idents
diff --git a/src/tools/rust-analyzer/crates/project-model/src/build_scripts.rs b/src/tools/rust-analyzer/crates/project-model/src/build_scripts.rs
index 84e772d1684a..837ea016193c 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/build_scripts.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/build_scripts.rs
@@ -43,10 +43,12 @@ impl WorkspaceBuildScripts {
         if let Some([program, args @ ..]) = config.run_build_script_command.as_deref() {
             let mut cmd = Command::new(program);
             cmd.args(args);
+            cmd.envs(&config.extra_env);
             return cmd;
         }
 
         let mut cmd = Command::new(toolchain::cargo());
+        cmd.envs(&config.extra_env);
 
         cmd.args(&["check", "--quiet", "--workspace", "--message-format=json"]);
 
diff --git a/src/tools/rust-analyzer/crates/project-model/src/cargo_workspace.rs b/src/tools/rust-analyzer/crates/project-model/src/cargo_workspace.rs
index eed955b42daa..736d80041bd5 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/cargo_workspace.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/cargo_workspace.rs
@@ -2,6 +2,7 @@
 
 use std::iter;
 use std::path::PathBuf;
+use std::str::from_utf8;
 use std::{ops, process::Command};
 
 use anyhow::{Context, Result};
@@ -98,6 +99,8 @@ pub struct CargoConfig {
     pub wrap_rustc_in_build_scripts: bool,
 
     pub run_build_script_command: Option<Vec<String>>,
+
+    pub extra_env: FxHashMap<String, String>,
 }
 
 impl CargoConfig {
@@ -263,8 +266,8 @@ impl CargoWorkspace {
         let target = config
             .target
             .clone()
-            .or_else(|| cargo_config_build_target(cargo_toml))
-            .or_else(|| rustc_discover_host_triple(cargo_toml));
+            .or_else(|| cargo_config_build_target(cargo_toml, config))
+            .or_else(|| rustc_discover_host_triple(cargo_toml, config));
 
         let mut meta = MetadataCommand::new();
         meta.cargo_path(toolchain::cargo());
@@ -292,8 +295,27 @@ impl CargoWorkspace {
         // unclear whether cargo itself supports it.
         progress("metadata".to_string());
 
-        let meta =
-            meta.exec().with_context(|| format!("Failed to run `{:?}`", meta.cargo_command()))?;
+        fn exec_with_env(
+            command: &cargo_metadata::MetadataCommand,
+            extra_env: &FxHashMap<String, String>,
+        ) -> Result<cargo_metadata::Metadata, cargo_metadata::Error> {
+            let mut command = command.cargo_command();
+            command.envs(extra_env);
+            let output = command.output()?;
+            if !output.status.success() {
+                return Err(cargo_metadata::Error::CargoMetadata {
+                    stderr: String::from_utf8(output.stderr)?,
+                });
+            }
+            let stdout = from_utf8(&output.stdout)?
+                .lines()
+                .find(|line| line.starts_with('{'))
+                .ok_or(cargo_metadata::Error::NoJson)?;
+            cargo_metadata::MetadataCommand::parse(stdout)
+        }
+
+        let meta = exec_with_env(&meta, &config.extra_env)
+            .with_context(|| format!("Failed to run `{:?}`", meta.cargo_command()))?;
 
         Ok(meta)
     }
@@ -463,8 +485,9 @@ impl CargoWorkspace {
     }
 }
 
-fn rustc_discover_host_triple(cargo_toml: &ManifestPath) -> Option<String> {
+fn rustc_discover_host_triple(cargo_toml: &ManifestPath, config: &CargoConfig) -> Option<String> {
     let mut rustc = Command::new(toolchain::rustc());
+    rustc.envs(&config.extra_env);
     rustc.current_dir(cargo_toml.parent()).arg("-vV");
     tracing::debug!("Discovering host platform by {:?}", rustc);
     match utf8_stdout(rustc) {
@@ -486,8 +509,9 @@ fn rustc_discover_host_triple(cargo_toml: &ManifestPath) -> Option<String> {
     }
 }
 
-fn cargo_config_build_target(cargo_toml: &ManifestPath) -> Option<String> {
+fn cargo_config_build_target(cargo_toml: &ManifestPath, config: &CargoConfig) -> Option<String> {
     let mut cargo_config = Command::new(toolchain::cargo());
+    cargo_config.envs(&config.extra_env);
     cargo_config
         .current_dir(cargo_toml.parent())
         .args(&["-Z", "unstable-options", "config", "get", "build.target"])
diff --git a/src/tools/rust-analyzer/crates/project-model/src/rustc_cfg.rs b/src/tools/rust-analyzer/crates/project-model/src/rustc_cfg.rs
index 17e244d0649e..486cb143b80b 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/rustc_cfg.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/rustc_cfg.rs
@@ -4,9 +4,13 @@ use std::process::Command;
 
 use anyhow::Result;
 
-use crate::{cfg_flag::CfgFlag, utf8_stdout, ManifestPath};
+use crate::{cfg_flag::CfgFlag, utf8_stdout, CargoConfig, ManifestPath};
 
-pub(crate) fn get(cargo_toml: Option<&ManifestPath>, target: Option<&str>) -> Vec<CfgFlag> {
+pub(crate) fn get(
+    cargo_toml: Option<&ManifestPath>,
+    target: Option<&str>,
+    config: &CargoConfig,
+) -> Vec<CfgFlag> {
     let _p = profile::span("rustc_cfg::get");
     let mut res = Vec::with_capacity(6 * 2 + 1);
 
@@ -18,7 +22,7 @@ pub(crate) fn get(cargo_toml: Option<&ManifestPath>, target: Option<&str>) -> Ve
         }
     }
 
-    match get_rust_cfgs(cargo_toml, target) {
+    match get_rust_cfgs(cargo_toml, target, config) {
         Ok(rustc_cfgs) => {
             tracing::debug!(
                 "rustc cfgs found: {:?}",
@@ -35,9 +39,14 @@ pub(crate) fn get(cargo_toml: Option<&ManifestPath>, target: Option<&str>) -> Ve
     res
 }
 
-fn get_rust_cfgs(cargo_toml: Option<&ManifestPath>, target: Option<&str>) -> Result<String> {
+fn get_rust_cfgs(
+    cargo_toml: Option<&ManifestPath>,
+    target: Option<&str>,
+    config: &CargoConfig,
+) -> Result<String> {
     if let Some(cargo_toml) = cargo_toml {
         let mut cargo_config = Command::new(toolchain::cargo());
+        cargo_config.envs(&config.extra_env);
         cargo_config
             .current_dir(cargo_toml.parent())
             .args(&["-Z", "unstable-options", "rustc", "--print", "cfg"])
@@ -52,6 +61,7 @@ fn get_rust_cfgs(cargo_toml: Option<&ManifestPath>, target: Option<&str>) -> Res
     }
     // using unstable cargo features failed, fall back to using plain rustc
     let mut cmd = Command::new(toolchain::rustc());
+    cmd.envs(&config.extra_env);
     cmd.args(&["--print", "cfg", "-O"]);
     if let Some(target) = target {
         cmd.args(&["--target", target]);
diff --git a/src/tools/rust-analyzer/crates/project-model/src/sysroot.rs b/src/tools/rust-analyzer/crates/project-model/src/sysroot.rs
index 362bb0f5e79c..3282719fef3d 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/sysroot.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/sysroot.rs
@@ -10,7 +10,7 @@ use anyhow::{format_err, Result};
 use la_arena::{Arena, Idx};
 use paths::{AbsPath, AbsPathBuf};
 
-use crate::{utf8_stdout, ManifestPath};
+use crate::{utf8_stdout, CargoConfig, ManifestPath};
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct Sysroot {
@@ -67,18 +67,20 @@ impl Sysroot {
         self.crates.iter().map(|(id, _data)| id)
     }
 
-    pub fn discover(dir: &AbsPath) -> Result<Sysroot> {
+    pub fn discover(dir: &AbsPath, config: &CargoConfig) -> Result<Sysroot> {
         tracing::debug!("Discovering sysroot for {}", dir.display());
-        let sysroot_dir = discover_sysroot_dir(dir)?;
-        let sysroot_src_dir = discover_sysroot_src_dir(&sysroot_dir, dir)?;
+        let sysroot_dir = discover_sysroot_dir(dir, config)?;
+        let sysroot_src_dir = discover_sysroot_src_dir(&sysroot_dir, dir, config)?;
         let res = Sysroot::load(sysroot_dir, sysroot_src_dir)?;
         Ok(res)
     }
 
-    pub fn discover_rustc(cargo_toml: &ManifestPath) -> Option<ManifestPath> {
+    pub fn discover_rustc(cargo_toml: &ManifestPath, config: &CargoConfig) -> Option<ManifestPath> {
         tracing::debug!("Discovering rustc source for {}", cargo_toml.display());
         let current_dir = cargo_toml.parent();
-        discover_sysroot_dir(current_dir).ok().and_then(|sysroot_dir| get_rustc_src(&sysroot_dir))
+        discover_sysroot_dir(current_dir, config)
+            .ok()
+            .and_then(|sysroot_dir| get_rustc_src(&sysroot_dir))
     }
 
     pub fn load(sysroot_dir: AbsPathBuf, sysroot_src_dir: AbsPathBuf) -> Result<Sysroot> {
@@ -144,8 +146,9 @@ impl Sysroot {
     }
 }
 
-fn discover_sysroot_dir(current_dir: &AbsPath) -> Result<AbsPathBuf> {
+fn discover_sysroot_dir(current_dir: &AbsPath, config: &CargoConfig) -> Result<AbsPathBuf> {
     let mut rustc = Command::new(toolchain::rustc());
+    rustc.envs(&config.extra_env);
     rustc.current_dir(current_dir).args(&["--print", "sysroot"]);
     tracing::debug!("Discovering sysroot by {:?}", rustc);
     let stdout = utf8_stdout(rustc)?;
@@ -155,6 +158,7 @@ fn discover_sysroot_dir(current_dir: &AbsPath) -> Result<AbsPathBuf> {
 fn discover_sysroot_src_dir(
     sysroot_path: &AbsPathBuf,
     current_dir: &AbsPath,
+    config: &CargoConfig,
 ) -> Result<AbsPathBuf> {
     if let Ok(path) = env::var("RUST_SRC_PATH") {
         let path = AbsPathBuf::try_from(path.as_str())
@@ -170,6 +174,7 @@ fn discover_sysroot_src_dir(
     get_rust_src(sysroot_path)
         .or_else(|| {
             let mut rustup = Command::new(toolchain::rustup());
+            rustup.envs(&config.extra_env);
             rustup.current_dir(current_dir).args(&["component", "add", "rust-src"]);
             utf8_stdout(rustup).ok()?;
             get_rust_src(sysroot_path)
diff --git a/src/tools/rust-analyzer/crates/project-model/src/tests.rs b/src/tools/rust-analyzer/crates/project-model/src/tests.rs
index 9ccb6e9101ef..bea624bd5419 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/tests.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/tests.rs
@@ -10,8 +10,8 @@ use paths::{AbsPath, AbsPathBuf};
 use serde::de::DeserializeOwned;
 
 use crate::{
-    CargoWorkspace, CfgOverrides, ProjectJson, ProjectJsonData, ProjectWorkspace, Sysroot,
-    WorkspaceBuildScripts,
+    CargoConfig, CargoWorkspace, CfgOverrides, ProjectJson, ProjectJsonData, ProjectWorkspace,
+    Sysroot, WorkspaceBuildScripts,
 };
 
 fn load_cargo(file: &str) -> CrateGraph {
@@ -92,13 +92,17 @@ fn rooted_project_json(data: ProjectJsonData) -> ProjectJson {
 }
 
 fn to_crate_graph(project_workspace: ProjectWorkspace) -> CrateGraph {
-    project_workspace.to_crate_graph(&mut |_, _| Ok(Vec::new()), &mut {
-        let mut counter = 0;
-        move |_path| {
-            counter += 1;
-            Some(FileId(counter))
-        }
-    })
+    project_workspace.to_crate_graph(
+        &mut |_, _| Ok(Vec::new()),
+        &mut {
+            let mut counter = 0;
+            move |_path| {
+                counter += 1;
+                Some(FileId(counter))
+            }
+        },
+        &CargoConfig::default(),
+    )
 }
 
 fn check_crate_graph(crate_graph: CrateGraph, expect: Expect) {
diff --git a/src/tools/rust-analyzer/crates/project-model/src/workspace.rs b/src/tools/rust-analyzer/crates/project-model/src/workspace.rs
index 818bbed6af2e..bc4ab45daeff 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/workspace.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/workspace.rs
@@ -156,11 +156,12 @@ impl ProjectWorkspace {
                 })?;
                 let project_location = project_json.parent().to_path_buf();
                 let project_json = ProjectJson::new(&project_location, data);
-                ProjectWorkspace::load_inline(project_json, config.target.as_deref())?
+                ProjectWorkspace::load_inline(project_json, config.target.as_deref(), config)?
             }
             ProjectManifest::CargoToml(cargo_toml) => {
                 let cargo_version = utf8_stdout({
                     let mut cmd = Command::new(toolchain::cargo());
+                    cmd.envs(&config.extra_env);
                     cmd.arg("--version");
                     cmd
                 })?;
@@ -186,7 +187,7 @@ impl ProjectWorkspace {
                 let sysroot = if config.no_sysroot {
                     None
                 } else {
-                    Some(Sysroot::discover(cargo_toml.parent()).with_context(|| {
+                    Some(Sysroot::discover(cargo_toml.parent(), config).with_context(|| {
                         format!(
                             "Failed to find sysroot for Cargo.toml file {}. Is rust-src installed?",
                             cargo_toml.display()
@@ -196,7 +197,7 @@ impl ProjectWorkspace {
 
                 let rustc_dir = match &config.rustc_source {
                     Some(RustcSource::Path(path)) => ManifestPath::try_from(path.clone()).ok(),
-                    Some(RustcSource::Discover) => Sysroot::discover_rustc(&cargo_toml),
+                    Some(RustcSource::Discover) => Sysroot::discover_rustc(&cargo_toml, config),
                     None => None,
                 };
 
@@ -216,7 +217,7 @@ impl ProjectWorkspace {
                     None => None,
                 };
 
-                let rustc_cfg = rustc_cfg::get(Some(&cargo_toml), config.target.as_deref());
+                let rustc_cfg = rustc_cfg::get(Some(&cargo_toml), config.target.as_deref(), config);
 
                 let cfg_overrides = config.cfg_overrides();
                 ProjectWorkspace::Cargo {
@@ -237,6 +238,7 @@ impl ProjectWorkspace {
     pub fn load_inline(
         project_json: ProjectJson,
         target: Option<&str>,
+        config: &CargoConfig,
     ) -> Result<ProjectWorkspace> {
         let sysroot = match (project_json.sysroot.clone(), project_json.sysroot_src.clone()) {
             (Some(sysroot), Some(sysroot_src)) => Some(Sysroot::load(sysroot, sysroot_src)?),
@@ -258,7 +260,7 @@ impl ProjectWorkspace {
             (None, None) => None,
         };
 
-        let rustc_cfg = rustc_cfg::get(None, target);
+        let rustc_cfg = rustc_cfg::get(None, target, config);
         Ok(ProjectWorkspace::Json { project: project_json, sysroot, rustc_cfg })
     }
 
@@ -268,8 +270,9 @@ impl ProjectWorkspace {
                 .first()
                 .and_then(|it| it.parent())
                 .ok_or_else(|| format_err!("No detached files to load"))?,
+            &CargoConfig::default(),
         )?;
-        let rustc_cfg = rustc_cfg::get(None, None);
+        let rustc_cfg = rustc_cfg::get(None, None, &CargoConfig::default());
         Ok(ProjectWorkspace::DetachedFiles { files: detached_files, sysroot, rustc_cfg })
     }
 
@@ -416,6 +419,7 @@ impl ProjectWorkspace {
         &self,
         load_proc_macro: &mut dyn FnMut(&str, &AbsPath) -> ProcMacroLoadResult,
         load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
+        config: &CargoConfig,
     ) -> CrateGraph {
         let _p = profile::span("ProjectWorkspace::to_crate_graph");
 
@@ -426,6 +430,7 @@ impl ProjectWorkspace {
                 load,
                 project,
                 sysroot,
+                config,
             ),
             ProjectWorkspace::Cargo {
                 cargo,
@@ -464,6 +469,7 @@ fn project_json_to_crate_graph(
     load: &mut dyn FnMut(&AbsPath) -> Option<FileId>,
     project: &ProjectJson,
     sysroot: &Option<Sysroot>,
+    config: &CargoConfig,
 ) -> CrateGraph {
     let mut crate_graph = CrateGraph::default();
     let sysroot_deps = sysroot
@@ -489,9 +495,9 @@ fn project_json_to_crate_graph(
             };
 
             let target_cfgs = match krate.target.as_deref() {
-                Some(target) => {
-                    cfg_cache.entry(target).or_insert_with(|| rustc_cfg::get(None, Some(target)))
-                }
+                Some(target) => cfg_cache
+                    .entry(target)
+                    .or_insert_with(|| rustc_cfg::get(None, Some(target), config)),
                 None => &rustc_cfg,
             };
 
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/analysis_stats.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/analysis_stats.rs
index f52e1e751278..80128e43fd3c 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/analysis_stats.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/analysis_stats.rs
@@ -80,7 +80,8 @@ impl flags::AnalysisStats {
             Some(build_scripts_sw.elapsed())
         };
 
-        let (host, vfs, _proc_macro) = load_workspace(workspace, &load_cargo_config)?;
+        let (host, vfs, _proc_macro) =
+            load_workspace(workspace, &cargo_config, &load_cargo_config)?;
         let db = host.raw_database();
         eprint!("{:<20} {}", "Database loaded:", db_load_sw.elapsed());
         eprint!(" (metadata {}", metadata_time);
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/load_cargo.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/load_cargo.rs
index 5d1c013c3275..88953096e2bc 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/load_cargo.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/load_cargo.rs
@@ -38,7 +38,7 @@ pub fn load_workspace_at(
         workspace.set_build_scripts(build_scripts)
     }
 
-    load_workspace(workspace, load_config)
+    load_workspace(workspace, cargo_config, load_config)
 }
 
 // Note: Since this function is used by external tools that use rust-analyzer as a library
@@ -48,6 +48,7 @@ pub fn load_workspace_at(
 // these tools need access to `ProjectWorkspace`, too, which `load_workspace_at` hides.
 pub fn load_workspace(
     ws: ProjectWorkspace,
+    cargo_config: &CargoConfig,
     load_config: &LoadCargoConfig,
 ) -> Result<(AnalysisHost, vfs::Vfs, Option<ProcMacroServer>)> {
     let (sender, receiver) = unbounded();
@@ -75,6 +76,7 @@ pub fn load_workspace(
             vfs.set_file_contents(path.clone(), contents);
             vfs.file_id(&path)
         },
+        cargo_config,
     );
 
     let project_folders = ProjectFolders::new(&[ws], &[]);
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/lsif.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/lsif.rs
index 491c55a04f8c..79577bf78c8f 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/lsif.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/lsif.rs
@@ -299,7 +299,8 @@ impl flags::Lsif {
 
         let workspace = ProjectWorkspace::load(manifest, &cargo_config, no_progress)?;
 
-        let (host, vfs, _proc_macro) = load_workspace(workspace, &load_cargo_config)?;
+        let (host, vfs, _proc_macro) =
+            load_workspace(workspace, &cargo_config, &load_cargo_config)?;
         let db = host.raw_database();
         let analysis = host.analysis();
 
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/scip.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/scip.rs
index 65cc993c45e7..05c16bb39e35 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/scip.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/cli/scip.rs
@@ -40,7 +40,7 @@ impl flags::Scip {
 
         let workspace = ProjectWorkspace::load(manifest, &cargo_config, no_progress)?;
 
-        let (host, vfs, _) = load_workspace(workspace, &load_cargo_config)?;
+        let (host, vfs, _) = load_workspace(workspace, &cargo_config, &load_cargo_config)?;
         let db = host.raw_database();
         let analysis = host.analysis();
 
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/config.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/config.rs
index 54dcb42d99c7..9ef79e6f3812 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/config.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/config.rs
@@ -84,6 +84,9 @@ config_data! {
         /// Use `RUSTC_WRAPPER=rust-analyzer` when running build scripts to
         /// avoid checking unnecessary things.
         cargo_buildScripts_useRustcWrapper: bool = "true",
+        /// Extra environment variables that will be set when running cargo, rustc
+        /// or other commands within the workspace. Useful for setting RUSTFLAGS.
+        cargo_extraEnv: FxHashMap<String, String> = "{}",
         /// List of features to activate.
         ///
         /// Set this to `"all"` to pass `--all-features` to cargo.
@@ -105,6 +108,8 @@ config_data! {
         checkOnSave_enable: bool                         = "true",
         /// Extra arguments for `cargo check`.
         checkOnSave_extraArgs: Vec<String>               = "[]",
+        /// Extra environment variables that will be set when running `cargo check`.
+        checkOnSave_extraEnv: FxHashMap<String, String> = "{}",
         /// List of features to activate. Defaults to
         /// `#rust-analyzer.cargo.features#`.
         ///
@@ -219,7 +224,6 @@ config_data! {
         files_excludeDirs: Vec<PathBuf> = "[]",
         /// Controls file watching implementation.
         files_watcher: FilesWatcherDef = "\"client\"",
-
         /// Enables highlighting of related references while the cursor is on `break`, `loop`, `while`, or `for` keywords.
         highlightRelated_breakPoints_enable: bool = "true",
         /// Enables highlighting of all exit points while the cursor is on any `return`, `?`, `fn`, or return type arrow (`->`).
@@ -263,6 +267,8 @@ config_data! {
         imports_group_enable: bool                           = "true",
         /// Whether to allow import insertion to merge new imports into single path glob imports like `use std::fmt::*;`.
         imports_merge_glob: bool           = "true",
+        /// Prefer to unconditionally use imports of the core and alloc crate, over the std crate.
+        imports_prefer_no_std: bool                     = "false",
         /// The path structure for newly inserted paths to use.
         imports_prefix: ImportPrefixDef               = "\"plain\"",
 
@@ -307,6 +313,7 @@ config_data! {
         /// Join lines unwraps trivial blocks.
         joinLines_unwrapTrivialBlock: bool = "true",
 
+
         /// Whether to show `Debug` lens. Only applies when
         /// `#rust-analyzer.lens.enable#` is set.
         lens_debug_enable: bool            = "true",
@@ -318,6 +325,8 @@ config_data! {
         /// Whether to show `Implementations` lens. Only applies when
         /// `#rust-analyzer.lens.enable#` is set.
         lens_implementations_enable: bool  = "true",
+        /// Where to render annotations.
+        lens_location: AnnotationLocation = "\"above_name\"",
         /// Whether to show `References` lens for Struct, Enum, and Union.
         /// Only applies when `#rust-analyzer.lens.enable#` is set.
         lens_references_adt_enable: bool = "false",
@@ -359,6 +368,9 @@ config_data! {
         /// this is rust-analyzer itself, but we override this in tests).
         procMacro_server: Option<PathBuf>          = "null",
 
+        /// Exclude imports from find-all-references.
+        references_excludeImports: bool = "false",
+
         /// Command to be executed instead of 'cargo' for runnables.
         runnables_command: Option<String> = "null",
         /// Additional arguments to be passed to cargo for runnables such as
@@ -494,6 +506,25 @@ pub struct LensConfig {
     pub refs_adt: bool,   // for Struct, Enum, Union and Trait
     pub refs_trait: bool, // for Struct, Enum, Union and Trait
     pub enum_variant_refs: bool,
+
+    // annotations
+    pub location: AnnotationLocation,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum AnnotationLocation {
+    AboveName,
+    AboveWholeItem,
+}
+
+impl From<AnnotationLocation> for ide::AnnotationLocation {
+    fn from(location: AnnotationLocation) -> Self {
+        match location {
+            AnnotationLocation::AboveName => ide::AnnotationLocation::AboveName,
+            AnnotationLocation::AboveWholeItem => ide::AnnotationLocation::AboveWholeItem,
+        }
+    }
 }
 
 impl LensConfig {
@@ -918,6 +949,7 @@ impl Config {
                 ExprFillDefaultDef::Default => ExprFillDefaultMode::Default,
             },
             insert_use: self.insert_use_config(),
+            prefer_no_std: self.data.imports_prefer_no_std,
         }
     }
 
@@ -929,6 +961,16 @@ impl Config {
         }
     }
 
+    pub fn extra_env(&self) -> &FxHashMap<String, String> {
+        &self.data.cargo_extraEnv
+    }
+
+    pub fn check_on_save_extra_env(&self) -> FxHashMap<String, String> {
+        let mut extra_env = self.data.cargo_extraEnv.clone();
+        extra_env.extend(self.data.checkOnSave_extraEnv.clone());
+        extra_env
+    }
+
     pub fn lru_capacity(&self) -> Option<usize> {
         self.data.lru_capacity
     }
@@ -998,6 +1040,7 @@ impl Config {
             unset_test_crates: UnsetTestCrates::Only(self.data.cargo_unsetTest.clone()),
             wrap_rustc_in_build_scripts: self.data.cargo_buildScripts_useRustcWrapper,
             run_build_script_command: self.data.cargo_buildScripts_overrideCommand.clone(),
+            extra_env: self.data.cargo_extraEnv.clone(),
         }
     }
 
@@ -1023,7 +1066,11 @@ impl Config {
             Some(args) if !args.is_empty() => {
                 let mut args = args.clone();
                 let command = args.remove(0);
-                FlycheckConfig::CustomCommand { command, args }
+                FlycheckConfig::CustomCommand {
+                    command,
+                    args,
+                    extra_env: self.check_on_save_extra_env(),
+                }
             }
             Some(_) | None => FlycheckConfig::CargoCommand {
                 command: self.data.checkOnSave_command.clone(),
@@ -1051,6 +1098,7 @@ impl Config {
                     CargoFeatures::Listed(it) => it,
                 },
                 extra_args: self.data.checkOnSave_extraArgs.clone(),
+                extra_env: self.check_on_save_extra_env(),
             },
         };
         Some(flycheck_config)
@@ -1133,6 +1181,7 @@ impl Config {
                 CallableCompletionDef::None => None,
             },
             insert_use: self.insert_use_config(),
+            prefer_no_std: self.data.imports_prefer_no_std,
             snippet_cap: SnippetCap::new(try_or_def!(
                 self.caps
                     .text_document
@@ -1147,6 +1196,10 @@ impl Config {
         }
     }
 
+    pub fn find_all_refs_exclude_imports(&self) -> bool {
+        self.data.references_excludeImports
+    }
+
     pub fn snippet_cap(&self) -> bool {
         self.experimental("snippetTextEdit")
     }
@@ -1156,6 +1209,7 @@ impl Config {
             snippet_cap: SnippetCap::new(self.experimental("snippetTextEdit")),
             allowed: None,
             insert_use: self.insert_use_config(),
+            prefer_no_std: self.data.imports_prefer_no_std,
         }
     }
 
@@ -1185,6 +1239,7 @@ impl Config {
             refs_trait: self.data.lens_enable && self.data.lens_references_trait_enable,
             enum_variant_refs: self.data.lens_enable
                 && self.data.lens_references_enumVariant_enable,
+            location: self.data.lens_location,
         }
     }
 
@@ -1921,6 +1976,14 @@ fn field_props(field: &str, ty: &str, doc: &[&str], default: &str) -> serde_json
                 "Use server-side file watching",
             ],
         },
+        "AnnotationLocation" => set! {
+            "type": "string",
+            "enum": ["above_name", "above_whole_item"],
+            "enumDescriptions": [
+                "Render annotations above the name of the item.",
+                "Render annotations above the whole item, including documentation comments and attributes."
+            ],
+        },
         _ => panic!("missing entry for {}: {}", ty, default),
     }
 
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/global_state.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/global_state.rs
index 706e1742dffd..92df4d70fd90 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/global_state.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/global_state.rs
@@ -116,6 +116,7 @@ pub(crate) struct GlobalStateSnapshot {
     pub(crate) semantic_tokens_cache: Arc<Mutex<FxHashMap<Url, SemanticTokens>>>,
     vfs: Arc<RwLock<(vfs::Vfs, NoHashHashMap<FileId, LineEndings>)>>,
     pub(crate) workspaces: Arc<Vec<ProjectWorkspace>>,
+    pub(crate) proc_macros_loaded: bool,
 }
 
 impl std::panic::UnwindSafe for GlobalStateSnapshot {}
@@ -256,6 +257,7 @@ impl GlobalState {
             check_fixes: Arc::clone(&self.diagnostics.check_fixes),
             mem_docs: self.mem_docs.clone(),
             semantic_tokens_cache: Arc::clone(&self.semantic_tokens_cache),
+            proc_macros_loaded: !self.fetch_build_data_queue.last_op_result().0.is_empty(),
         }
     }
 
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers.rs
index d89f0f5a3cf4..8c3ea77d0611 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers.rs
@@ -10,8 +10,8 @@ use std::{
 use anyhow::Context;
 use ide::{
     AnnotationConfig, AssistKind, AssistResolveStrategy, FileId, FilePosition, FileRange,
-    HoverAction, HoverGotoTypeData, Query, RangeInfo, Runnable, RunnableKind, SingleResolve,
-    SourceChange, TextEdit,
+    HoverAction, HoverGotoTypeData, Query, RangeInfo, ReferenceCategory, Runnable, RunnableKind,
+    SingleResolve, SourceChange, TextEdit,
 };
 use ide_db::SymbolKind;
 use lsp_server::ErrorCode;
@@ -1012,6 +1012,8 @@ pub(crate) fn handle_references(
     let _p = profile::span("handle_references");
     let position = from_proto::file_position(&snap, params.text_document_position)?;
 
+    let exclude_imports = snap.config.find_all_refs_exclude_imports();
+
     let refs = match snap.analysis.find_all_refs(position, None)? {
         None => return Ok(None),
         Some(refs) => refs,
@@ -1032,7 +1034,11 @@ pub(crate) fn handle_references(
             refs.references
                 .into_iter()
                 .flat_map(|(file_id, refs)| {
-                    refs.into_iter().map(move |(range, _)| FileRange { file_id, range })
+                    refs.into_iter()
+                        .filter(|&(_, category)| {
+                            !exclude_imports || category != Some(ReferenceCategory::Import)
+                        })
+                        .map(move |(range, _)| FileRange { file_id, range })
                 })
                 .chain(decl)
         })
@@ -1234,6 +1240,7 @@ pub(crate) fn handle_code_lens(
             annotate_references: lens_config.refs_adt,
             annotate_method_references: lens_config.method_refs,
             annotate_enum_variant_references: lens_config.enum_variant_refs,
+            location: lens_config.location.into(),
         },
         file_id,
     )?;
@@ -1283,7 +1290,7 @@ pub(crate) fn handle_document_highlight(
         .into_iter()
         .map(|ide::HighlightedRange { range, category }| lsp_types::DocumentHighlight {
             range: to_proto::range(&line_index, range),
-            kind: category.map(to_proto::document_highlight_kind),
+            kind: category.and_then(to_proto::document_highlight_kind),
         })
         .collect();
     Ok(Some(res))
@@ -1362,7 +1369,7 @@ pub(crate) fn handle_inlay_hints(
             .map(|it| {
                 to_proto::inlay_hint(&snap, &line_index, inlay_hints_config.render_colons, it)
             })
-            .collect(),
+            .collect::<Result<Vec<_>>>()?,
     ))
 }
 
@@ -1504,7 +1511,11 @@ pub(crate) fn handle_semantic_tokens_full(
     let text = snap.analysis.file_text(file_id)?;
     let line_index = snap.file_line_index(file_id)?;
 
-    let highlights = snap.analysis.highlight(snap.config.highlighting_config(), file_id)?;
+    let mut highlight_config = snap.config.highlighting_config();
+    // Avoid flashing a bunch of unresolved references when the proc-macro servers haven't been spawned yet.
+    highlight_config.syntactic_name_ref_highlighting = !snap.proc_macros_loaded;
+
+    let highlights = snap.analysis.highlight(highlight_config, file_id)?;
     let semantic_tokens = to_proto::semantic_tokens(&text, &line_index, highlights);
 
     // Unconditionally cache the tokens
@@ -1523,7 +1534,11 @@ pub(crate) fn handle_semantic_tokens_full_delta(
     let text = snap.analysis.file_text(file_id)?;
     let line_index = snap.file_line_index(file_id)?;
 
-    let highlights = snap.analysis.highlight(snap.config.highlighting_config(), file_id)?;
+    let mut highlight_config = snap.config.highlighting_config();
+    // Avoid flashing a bunch of unresolved references when the proc-macro servers haven't been spawned yet.
+    highlight_config.syntactic_name_ref_highlighting = !snap.proc_macros_loaded;
+
+    let highlights = snap.analysis.highlight(highlight_config, file_id)?;
     let semantic_tokens = to_proto::semantic_tokens(&text, &line_index, highlights);
 
     let mut cache = snap.semantic_tokens_cache.lock();
@@ -1774,6 +1789,7 @@ fn run_rustfmt(
     let mut command = match snap.config.rustfmt() {
         RustfmtConfig::Rustfmt { extra_args, enable_range_formatting } => {
             let mut cmd = process::Command::new(toolchain::rustfmt());
+            cmd.envs(snap.config.extra_env());
             cmd.args(extra_args);
             // try to chdir to the file so we can respect `rustfmt.toml`
             // FIXME: use `rustfmt --config-path` once
@@ -1831,6 +1847,7 @@ fn run_rustfmt(
         }
         RustfmtConfig::CustomCommand { command, args } => {
             let mut cmd = process::Command::new(command);
+            cmd.envs(snap.config.extra_env());
             cmd.args(args);
             cmd
         }
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/integrated_benchmarks.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/integrated_benchmarks.rs
index e49a98685a7f..96b1cb6b1271 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/integrated_benchmarks.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/integrated_benchmarks.rs
@@ -145,6 +145,7 @@ fn integrated_completion_benchmark() {
                 skip_glob_imports: true,
             },
             snippets: Vec::new(),
+            prefer_no_std: false,
         };
         let position =
             FilePosition { file_id, offset: TextSize::try_from(completion_offset).unwrap() };
@@ -182,6 +183,7 @@ fn integrated_completion_benchmark() {
                 skip_glob_imports: true,
             },
             snippets: Vec::new(),
+            prefer_no_std: false,
         };
         let position =
             FilePosition { file_id, offset: TextSize::try_from(completion_offset).unwrap() };
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs
index ceb2a6d703d9..4cf5de46c485 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs
@@ -143,6 +143,7 @@ impl GlobalState {
                             project_model::ProjectWorkspace::load_inline(
                                 it.clone(),
                                 cargo_config.target.as_deref(),
+                                &cargo_config,
                             )
                         }
                     })
@@ -314,7 +315,9 @@ impl GlobalState {
                         let mut args = args.clone();
                         let mut path = path.clone();
 
-                        if let ProjectWorkspace::Cargo { sysroot, .. } = ws {
+                        if let ProjectWorkspace::Cargo { sysroot, .. }
+                        | ProjectWorkspace::Json { sysroot, .. } = ws
+                        {
                             tracing::debug!("Found a cargo workspace...");
                             if let Some(sysroot) = sysroot.as_ref() {
                                 tracing::debug!("Found a cargo workspace with a sysroot...");
@@ -347,8 +350,8 @@ impl GlobalState {
                             error
                         })
                     })
-                    .collect();
-            }
+                    .collect()
+            };
         }
 
         let watch = match files_config.watcher {
@@ -396,7 +399,11 @@ impl GlobalState {
                         dummy_replacements.get(crate_name).map(|v| &**v).unwrap_or_default(),
                     )
                 };
-                crate_graph.extend(ws.to_crate_graph(&mut load_proc_macro, &mut load));
+                crate_graph.extend(ws.to_crate_graph(
+                    &mut load_proc_macro,
+                    &mut load,
+                    &self.config.cargo(),
+                ));
             }
             crate_graph
         };
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/to_proto.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/to_proto.rs
index 102cd6029504..1de801e23e5c 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/to_proto.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/to_proto.rs
@@ -9,8 +9,9 @@ use ide::{
     Annotation, AnnotationKind, Assist, AssistKind, Cancellable, CompletionItem,
     CompletionItemKind, CompletionRelevance, Documentation, FileId, FileRange, FileSystemEdit,
     Fold, FoldKind, Highlight, HlMod, HlOperator, HlPunct, HlRange, HlTag, Indel, InlayHint,
-    InlayKind, Markup, NavigationTarget, ReferenceCategory, RenameError, Runnable, Severity,
-    SignatureHelp, SourceChange, StructureNodeKind, SymbolKind, TextEdit, TextRange, TextSize,
+    InlayHintLabel, InlayKind, Markup, NavigationTarget, ReferenceCategory, RenameError, Runnable,
+    Severity, SignatureHelp, SourceChange, StructureNodeKind, SymbolKind, TextEdit, TextRange,
+    TextSize,
 };
 use itertools::Itertools;
 use serde_json::to_value;
@@ -82,10 +83,11 @@ pub(crate) fn structure_node_kind(kind: StructureNodeKind) -> lsp_types::SymbolK
 
 pub(crate) fn document_highlight_kind(
     category: ReferenceCategory,
-) -> lsp_types::DocumentHighlightKind {
+) -> Option<lsp_types::DocumentHighlightKind> {
     match category {
-        ReferenceCategory::Read => lsp_types::DocumentHighlightKind::READ,
-        ReferenceCategory::Write => lsp_types::DocumentHighlightKind::WRITE,
+        ReferenceCategory::Read => Some(lsp_types::DocumentHighlightKind::READ),
+        ReferenceCategory::Write => Some(lsp_types::DocumentHighlightKind::WRITE),
+        ReferenceCategory::Import => None,
     }
 }
 
@@ -426,9 +428,16 @@ pub(crate) fn inlay_hint(
     snap: &GlobalStateSnapshot,
     line_index: &LineIndex,
     render_colons: bool,
-    inlay_hint: InlayHint,
-) -> lsp_types::InlayHint {
-    lsp_types::InlayHint {
+    mut inlay_hint: InlayHint,
+) -> Result<lsp_types::InlayHint> {
+    match inlay_hint.kind {
+        InlayKind::ParameterHint if render_colons => inlay_hint.label.append_str(":"),
+        InlayKind::TypeHint if render_colons => inlay_hint.label.prepend_str(": "),
+        InlayKind::ClosureReturnTypeHint => inlay_hint.label.prepend_str(" -> "),
+        _ => {}
+    }
+
+    Ok(lsp_types::InlayHint {
         position: match inlay_hint.kind {
             // before annotated thing
             InlayKind::ParameterHint
@@ -459,15 +468,9 @@ pub(crate) fn inlay_hint(
             | InlayKind::ImplicitReborrowHint
             | InlayKind::TypeHint
             | InlayKind::ClosingBraceHint => false,
-            InlayKind::BindingModeHint => inlay_hint.label != "&",
+            InlayKind::BindingModeHint => inlay_hint.label.as_simple_str() != Some("&"),
             InlayKind::ParameterHint | InlayKind::LifetimeHint => true,
         }),
-        label: lsp_types::InlayHintLabel::String(match inlay_hint.kind {
-            InlayKind::ParameterHint if render_colons => format!("{}:", inlay_hint.label),
-            InlayKind::TypeHint if render_colons => format!(": {}", inlay_hint.label),
-            InlayKind::ClosureReturnTypeHint => format!(" -> {}", inlay_hint.label),
-            _ => inlay_hint.label.clone(),
-        }),
         kind: match inlay_hint.kind {
             InlayKind::ParameterHint => Some(lsp_types::InlayHintKind::PARAMETER),
             InlayKind::ClosureReturnTypeHint | InlayKind::TypeHint | InlayKind::ChainingHint => {
@@ -506,9 +509,36 @@ pub(crate) fn inlay_hint(
         })(),
         tooltip: Some(match inlay_hint.tooltip {
             Some(ide::InlayTooltip::String(s)) => lsp_types::InlayHintTooltip::String(s),
-            _ => lsp_types::InlayHintTooltip::String(inlay_hint.label),
+            _ => lsp_types::InlayHintTooltip::String(inlay_hint.label.to_string()),
         }),
-    }
+        label: inlay_hint_label(snap, inlay_hint.label)?,
+    })
+}
+
+fn inlay_hint_label(
+    snap: &GlobalStateSnapshot,
+    label: InlayHintLabel,
+) -> Result<lsp_types::InlayHintLabel> {
+    Ok(match label.as_simple_str() {
+        Some(s) => lsp_types::InlayHintLabel::String(s.into()),
+        None => lsp_types::InlayHintLabel::LabelParts(
+            label
+                .parts
+                .into_iter()
+                .map(|part| {
+                    Ok(lsp_types::InlayHintLabelPart {
+                        value: part.text,
+                        tooltip: None,
+                        location: part
+                            .linked_location
+                            .map(|range| location(snap, range))
+                            .transpose()?,
+                        command: None,
+                    })
+                })
+                .collect::<Result<Vec<_>>>()?,
+        ),
+    })
 }
 
 static TOKEN_RESULT_COUNTER: AtomicU32 = AtomicU32::new(1);
diff --git a/src/tools/rust-analyzer/crates/syntax/rust.ungram b/src/tools/rust-analyzer/crates/syntax/rust.ungram
index 62aa47839942..894795435451 100644
--- a/src/tools/rust-analyzer/crates/syntax/rust.ungram
+++ b/src/tools/rust-analyzer/crates/syntax/rust.ungram
@@ -343,7 +343,6 @@ Expr =
 | Literal
 | LoopExpr
 | MacroExpr
-| MacroStmts
 | MatchExpr
 | MethodCallExpr
 | ParenExpr
diff --git a/src/tools/rust-analyzer/crates/syntax/src/ast/edit_in_place.rs b/src/tools/rust-analyzer/crates/syntax/src/ast/edit_in_place.rs
index 8efd58e2c39a..eadebbe8a212 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/ast/edit_in_place.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/ast/edit_in_place.rs
@@ -248,8 +248,12 @@ impl ast::WhereClause {
     }
 }
 
-impl ast::TypeBoundList {
-    pub fn remove(&self) {
+pub trait Removable: AstNode {
+    fn remove(&self);
+}
+
+impl Removable for ast::TypeBoundList {
+    fn remove(&self) {
         match self.syntax().siblings_with_tokens(Direction::Prev).find(|it| it.kind() == T![:]) {
             Some(colon) => ted::remove_all(colon..=self.syntax().clone().into()),
             None => ted::remove(self.syntax()),
@@ -267,8 +271,8 @@ impl ast::PathSegment {
     }
 }
 
-impl ast::UseTree {
-    pub fn remove(&self) {
+impl Removable for ast::UseTree {
+    fn remove(&self) {
         for dir in [Direction::Next, Direction::Prev] {
             if let Some(next_use_tree) = neighbor(self, dir) {
                 let separators = self
@@ -282,7 +286,9 @@ impl ast::UseTree {
         }
         ted::remove(self.syntax());
     }
+}
 
+impl ast::UseTree {
     pub fn get_or_create_use_tree_list(&self) -> ast::UseTreeList {
         match self.use_tree_list() {
             Some(it) => it,
@@ -373,8 +379,8 @@ impl ast::UseTreeList {
     }
 }
 
-impl ast::Use {
-    pub fn remove(&self) {
+impl Removable for ast::Use {
+    fn remove(&self) {
         let next_ws = self
             .syntax()
             .next_sibling_or_token()
@@ -444,8 +450,8 @@ impl ast::Fn {
     }
 }
 
-impl ast::MatchArm {
-    pub fn remove(&self) {
+impl Removable for ast::MatchArm {
+    fn remove(&self) {
         if let Some(sibling) = self.syntax().prev_sibling_or_token() {
             if sibling.kind() == SyntaxKind::WHITESPACE {
                 ted::remove(sibling);
diff --git a/src/tools/rust-analyzer/crates/syntax/src/ast/generated/nodes.rs b/src/tools/rust-analyzer/crates/syntax/src/ast/generated/nodes.rs
index 63309a155219..449402e5f5b3 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/ast/generated/nodes.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/ast/generated/nodes.rs
@@ -1526,7 +1526,6 @@ pub enum Expr {
     Literal(Literal),
     LoopExpr(LoopExpr),
     MacroExpr(MacroExpr),
-    MacroStmts(MacroStmts),
     MatchExpr(MatchExpr),
     MethodCallExpr(MethodCallExpr),
     ParenExpr(ParenExpr),
@@ -3169,10 +3168,7 @@ impl From<ConstArg> for GenericArg {
 }
 impl AstNode for GenericArg {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            TYPE_ARG | ASSOC_TYPE_ARG | LIFETIME_ARG | CONST_ARG => true,
-            _ => false,
-        }
+        matches!(kind, TYPE_ARG | ASSOC_TYPE_ARG | LIFETIME_ARG | CONST_ARG)
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
@@ -3237,12 +3233,23 @@ impl From<TupleType> for Type {
 }
 impl AstNode for Type {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            ARRAY_TYPE | DYN_TRAIT_TYPE | FN_PTR_TYPE | FOR_TYPE | IMPL_TRAIT_TYPE | INFER_TYPE
-            | MACRO_TYPE | NEVER_TYPE | PAREN_TYPE | PATH_TYPE | PTR_TYPE | REF_TYPE
-            | SLICE_TYPE | TUPLE_TYPE => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            ARRAY_TYPE
+                | DYN_TRAIT_TYPE
+                | FN_PTR_TYPE
+                | FOR_TYPE
+                | IMPL_TRAIT_TYPE
+                | INFER_TYPE
+                | MACRO_TYPE
+                | NEVER_TYPE
+                | PAREN_TYPE
+                | PATH_TYPE
+                | PTR_TYPE
+                | REF_TYPE
+                | SLICE_TYPE
+                | TUPLE_TYPE
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
@@ -3334,9 +3341,6 @@ impl From<LoopExpr> for Expr {
 impl From<MacroExpr> for Expr {
     fn from(node: MacroExpr) -> Expr { Expr::MacroExpr(node) }
 }
-impl From<MacroStmts> for Expr {
-    fn from(node: MacroStmts) -> Expr { Expr::MacroStmts(node) }
-}
 impl From<MatchExpr> for Expr {
     fn from(node: MatchExpr) -> Expr { Expr::MatchExpr(node) }
 }
@@ -3384,15 +3388,41 @@ impl From<UnderscoreExpr> for Expr {
 }
 impl AstNode for Expr {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            ARRAY_EXPR | AWAIT_EXPR | BIN_EXPR | BLOCK_EXPR | BOX_EXPR | BREAK_EXPR | CALL_EXPR
-            | CAST_EXPR | CLOSURE_EXPR | CONTINUE_EXPR | FIELD_EXPR | FOR_EXPR | IF_EXPR
-            | INDEX_EXPR | LITERAL | LOOP_EXPR | MACRO_EXPR | MACRO_STMTS | MATCH_EXPR
-            | METHOD_CALL_EXPR | PAREN_EXPR | PATH_EXPR | PREFIX_EXPR | RANGE_EXPR
-            | RECORD_EXPR | REF_EXPR | RETURN_EXPR | TRY_EXPR | TUPLE_EXPR | WHILE_EXPR
-            | YIELD_EXPR | LET_EXPR | UNDERSCORE_EXPR => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            ARRAY_EXPR
+                | AWAIT_EXPR
+                | BIN_EXPR
+                | BLOCK_EXPR
+                | BOX_EXPR
+                | BREAK_EXPR
+                | CALL_EXPR
+                | CAST_EXPR
+                | CLOSURE_EXPR
+                | CONTINUE_EXPR
+                | FIELD_EXPR
+                | FOR_EXPR
+                | IF_EXPR
+                | INDEX_EXPR
+                | LITERAL
+                | LOOP_EXPR
+                | MACRO_EXPR
+                | MATCH_EXPR
+                | METHOD_CALL_EXPR
+                | PAREN_EXPR
+                | PATH_EXPR
+                | PREFIX_EXPR
+                | RANGE_EXPR
+                | RECORD_EXPR
+                | REF_EXPR
+                | RETURN_EXPR
+                | TRY_EXPR
+                | TUPLE_EXPR
+                | WHILE_EXPR
+                | YIELD_EXPR
+                | LET_EXPR
+                | UNDERSCORE_EXPR
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
@@ -3413,7 +3443,6 @@ impl AstNode for Expr {
             LITERAL => Expr::Literal(Literal { syntax }),
             LOOP_EXPR => Expr::LoopExpr(LoopExpr { syntax }),
             MACRO_EXPR => Expr::MacroExpr(MacroExpr { syntax }),
-            MACRO_STMTS => Expr::MacroStmts(MacroStmts { syntax }),
             MATCH_EXPR => Expr::MatchExpr(MatchExpr { syntax }),
             METHOD_CALL_EXPR => Expr::MethodCallExpr(MethodCallExpr { syntax }),
             PAREN_EXPR => Expr::ParenExpr(ParenExpr { syntax }),
@@ -3452,7 +3481,6 @@ impl AstNode for Expr {
             Expr::Literal(it) => &it.syntax,
             Expr::LoopExpr(it) => &it.syntax,
             Expr::MacroExpr(it) => &it.syntax,
-            Expr::MacroStmts(it) => &it.syntax,
             Expr::MatchExpr(it) => &it.syntax,
             Expr::MethodCallExpr(it) => &it.syntax,
             Expr::ParenExpr(it) => &it.syntax,
@@ -3521,11 +3549,25 @@ impl From<Use> for Item {
 }
 impl AstNode for Item {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            CONST | ENUM | EXTERN_BLOCK | EXTERN_CRATE | FN | IMPL | MACRO_CALL | MACRO_RULES
-            | MACRO_DEF | MODULE | STATIC | STRUCT | TRAIT | TYPE_ALIAS | UNION | USE => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            CONST
+                | ENUM
+                | EXTERN_BLOCK
+                | EXTERN_CRATE
+                | FN
+                | IMPL
+                | MACRO_CALL
+                | MACRO_RULES
+                | MACRO_DEF
+                | MODULE
+                | STATIC
+                | STRUCT
+                | TRAIT
+                | TYPE_ALIAS
+                | UNION
+                | USE
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
@@ -3629,12 +3671,25 @@ impl From<ConstBlockPat> for Pat {
 }
 impl AstNode for Pat {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            IDENT_PAT | BOX_PAT | REST_PAT | LITERAL_PAT | MACRO_PAT | OR_PAT | PAREN_PAT
-            | PATH_PAT | WILDCARD_PAT | RANGE_PAT | RECORD_PAT | REF_PAT | SLICE_PAT
-            | TUPLE_PAT | TUPLE_STRUCT_PAT | CONST_BLOCK_PAT => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            IDENT_PAT
+                | BOX_PAT
+                | REST_PAT
+                | LITERAL_PAT
+                | MACRO_PAT
+                | OR_PAT
+                | PAREN_PAT
+                | PATH_PAT
+                | WILDCARD_PAT
+                | RANGE_PAT
+                | RECORD_PAT
+                | REF_PAT
+                | SLICE_PAT
+                | TUPLE_PAT
+                | TUPLE_STRUCT_PAT
+                | CONST_BLOCK_PAT
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
@@ -3686,12 +3741,7 @@ impl From<TupleFieldList> for FieldList {
     fn from(node: TupleFieldList) -> FieldList { FieldList::TupleFieldList(node) }
 }
 impl AstNode for FieldList {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            RECORD_FIELD_LIST | TUPLE_FIELD_LIST => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, RECORD_FIELD_LIST | TUPLE_FIELD_LIST) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
             RECORD_FIELD_LIST => FieldList::RecordFieldList(RecordFieldList { syntax }),
@@ -3717,12 +3767,7 @@ impl From<Union> for Adt {
     fn from(node: Union) -> Adt { Adt::Union(node) }
 }
 impl AstNode for Adt {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            ENUM | STRUCT | UNION => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, ENUM | STRUCT | UNION) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
             ENUM => Adt::Enum(Enum { syntax }),
@@ -3753,12 +3798,7 @@ impl From<TypeAlias> for AssocItem {
     fn from(node: TypeAlias) -> AssocItem { AssocItem::TypeAlias(node) }
 }
 impl AstNode for AssocItem {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            CONST | FN | MACRO_CALL | TYPE_ALIAS => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, CONST | FN | MACRO_CALL | TYPE_ALIAS) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
             CONST => AssocItem::Const(Const { syntax }),
@@ -3791,12 +3831,7 @@ impl From<TypeAlias> for ExternItem {
     fn from(node: TypeAlias) -> ExternItem { ExternItem::TypeAlias(node) }
 }
 impl AstNode for ExternItem {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            FN | MACRO_CALL | STATIC | TYPE_ALIAS => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, FN | MACRO_CALL | STATIC | TYPE_ALIAS) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
             FN => ExternItem::Fn(Fn { syntax }),
@@ -3827,10 +3862,7 @@ impl From<TypeParam> for GenericParam {
 }
 impl AstNode for GenericParam {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            CONST_PARAM | LIFETIME_PARAM | TYPE_PARAM => true,
-            _ => false,
-        }
+        matches!(kind, CONST_PARAM | LIFETIME_PARAM | TYPE_PARAM)
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
@@ -3856,12 +3888,7 @@ impl AnyHasArgList {
     }
 }
 impl AstNode for AnyHasArgList {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            CALL_EXPR | METHOD_CALL_EXPR => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, CALL_EXPR | METHOD_CALL_EXPR) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasArgList { syntax })
     }
@@ -3875,76 +3902,76 @@ impl AnyHasAttrs {
 }
 impl AstNode for AnyHasAttrs {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
+        matches!(
+            kind,
             MACRO_CALL
-            | SOURCE_FILE
-            | CONST
-            | ENUM
-            | EXTERN_BLOCK
-            | EXTERN_CRATE
-            | FN
-            | IMPL
-            | MACRO_RULES
-            | MACRO_DEF
-            | MODULE
-            | STATIC
-            | STRUCT
-            | TRAIT
-            | TYPE_ALIAS
-            | UNION
-            | USE
-            | ITEM_LIST
-            | BLOCK_EXPR
-            | SELF_PARAM
-            | PARAM
-            | RECORD_FIELD
-            | TUPLE_FIELD
-            | VARIANT
-            | ASSOC_ITEM_LIST
-            | EXTERN_ITEM_LIST
-            | CONST_PARAM
-            | LIFETIME_PARAM
-            | TYPE_PARAM
-            | LET_STMT
-            | ARRAY_EXPR
-            | AWAIT_EXPR
-            | BIN_EXPR
-            | BOX_EXPR
-            | BREAK_EXPR
-            | CALL_EXPR
-            | CAST_EXPR
-            | CLOSURE_EXPR
-            | CONTINUE_EXPR
-            | FIELD_EXPR
-            | FOR_EXPR
-            | IF_EXPR
-            | INDEX_EXPR
-            | LITERAL
-            | LOOP_EXPR
-            | MATCH_EXPR
-            | METHOD_CALL_EXPR
-            | PAREN_EXPR
-            | PATH_EXPR
-            | PREFIX_EXPR
-            | RANGE_EXPR
-            | REF_EXPR
-            | RETURN_EXPR
-            | TRY_EXPR
-            | TUPLE_EXPR
-            | WHILE_EXPR
-            | YIELD_EXPR
-            | LET_EXPR
-            | UNDERSCORE_EXPR
-            | STMT_LIST
-            | RECORD_EXPR_FIELD_LIST
-            | RECORD_EXPR_FIELD
-            | MATCH_ARM_LIST
-            | MATCH_ARM
-            | IDENT_PAT
-            | REST_PAT
-            | RECORD_PAT_FIELD => true,
-            _ => false,
-        }
+                | SOURCE_FILE
+                | CONST
+                | ENUM
+                | EXTERN_BLOCK
+                | EXTERN_CRATE
+                | FN
+                | IMPL
+                | MACRO_RULES
+                | MACRO_DEF
+                | MODULE
+                | STATIC
+                | STRUCT
+                | TRAIT
+                | TYPE_ALIAS
+                | UNION
+                | USE
+                | ITEM_LIST
+                | BLOCK_EXPR
+                | SELF_PARAM
+                | PARAM
+                | RECORD_FIELD
+                | TUPLE_FIELD
+                | VARIANT
+                | ASSOC_ITEM_LIST
+                | EXTERN_ITEM_LIST
+                | CONST_PARAM
+                | LIFETIME_PARAM
+                | TYPE_PARAM
+                | LET_STMT
+                | ARRAY_EXPR
+                | AWAIT_EXPR
+                | BIN_EXPR
+                | BOX_EXPR
+                | BREAK_EXPR
+                | CALL_EXPR
+                | CAST_EXPR
+                | CLOSURE_EXPR
+                | CONTINUE_EXPR
+                | FIELD_EXPR
+                | FOR_EXPR
+                | IF_EXPR
+                | INDEX_EXPR
+                | LITERAL
+                | LOOP_EXPR
+                | MATCH_EXPR
+                | METHOD_CALL_EXPR
+                | PAREN_EXPR
+                | PATH_EXPR
+                | PREFIX_EXPR
+                | RANGE_EXPR
+                | REF_EXPR
+                | RETURN_EXPR
+                | TRY_EXPR
+                | TUPLE_EXPR
+                | WHILE_EXPR
+                | YIELD_EXPR
+                | LET_EXPR
+                | UNDERSCORE_EXPR
+                | STMT_LIST
+                | RECORD_EXPR_FIELD_LIST
+                | RECORD_EXPR_FIELD
+                | MATCH_ARM_LIST
+                | MATCH_ARM
+                | IDENT_PAT
+                | REST_PAT
+                | RECORD_PAT_FIELD
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasAttrs { syntax })
@@ -3959,12 +3986,29 @@ impl AnyHasDocComments {
 }
 impl AstNode for AnyHasDocComments {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            MACRO_CALL | SOURCE_FILE | CONST | ENUM | EXTERN_BLOCK | EXTERN_CRATE | FN | IMPL
-            | MACRO_RULES | MACRO_DEF | MODULE | STATIC | STRUCT | TRAIT | TYPE_ALIAS | UNION
-            | USE | RECORD_FIELD | TUPLE_FIELD | VARIANT => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            MACRO_CALL
+                | SOURCE_FILE
+                | CONST
+                | ENUM
+                | EXTERN_BLOCK
+                | EXTERN_CRATE
+                | FN
+                | IMPL
+                | MACRO_RULES
+                | MACRO_DEF
+                | MODULE
+                | STATIC
+                | STRUCT
+                | TRAIT
+                | TYPE_ALIAS
+                | UNION
+                | USE
+                | RECORD_FIELD
+                | TUPLE_FIELD
+                | VARIANT
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasDocComments { syntax })
@@ -3979,10 +4023,7 @@ impl AnyHasGenericParams {
 }
 impl AstNode for AnyHasGenericParams {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            ENUM | FN | IMPL | STRUCT | TRAIT | TYPE_ALIAS | UNION => true,
-            _ => false,
-        }
+        matches!(kind, ENUM | FN | IMPL | STRUCT | TRAIT | TYPE_ALIAS | UNION)
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasGenericParams { syntax })
@@ -3996,12 +4037,7 @@ impl AnyHasLoopBody {
     }
 }
 impl AstNode for AnyHasLoopBody {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            FOR_EXPR | LOOP_EXPR | WHILE_EXPR => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, FOR_EXPR | LOOP_EXPR | WHILE_EXPR) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasLoopBody { syntax })
     }
@@ -4014,12 +4050,7 @@ impl AnyHasModuleItem {
     }
 }
 impl AstNode for AnyHasModuleItem {
-    fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            MACRO_ITEMS | SOURCE_FILE | ITEM_LIST => true,
-            _ => false,
-        }
-    }
+    fn can_cast(kind: SyntaxKind) -> bool { matches!(kind, MACRO_ITEMS | SOURCE_FILE | ITEM_LIST) }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasModuleItem { syntax })
     }
@@ -4033,12 +4064,27 @@ impl AnyHasName {
 }
 impl AstNode for AnyHasName {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            CONST | ENUM | FN | MACRO_RULES | MACRO_DEF | MODULE | STATIC | STRUCT | TRAIT
-            | TYPE_ALIAS | UNION | RENAME | SELF_PARAM | RECORD_FIELD | VARIANT | CONST_PARAM
-            | TYPE_PARAM | IDENT_PAT => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            CONST
+                | ENUM
+                | FN
+                | MACRO_RULES
+                | MACRO_DEF
+                | MODULE
+                | STATIC
+                | STRUCT
+                | TRAIT
+                | TYPE_ALIAS
+                | UNION
+                | RENAME
+                | SELF_PARAM
+                | RECORD_FIELD
+                | VARIANT
+                | CONST_PARAM
+                | TYPE_PARAM
+                | IDENT_PAT
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasName { syntax })
@@ -4053,10 +4099,10 @@ impl AnyHasTypeBounds {
 }
 impl AstNode for AnyHasTypeBounds {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            ASSOC_TYPE_ARG | TRAIT | TYPE_ALIAS | LIFETIME_PARAM | TYPE_PARAM | WHERE_PRED => true,
-            _ => false,
-        }
+        matches!(
+            kind,
+            ASSOC_TYPE_ARG | TRAIT | TYPE_ALIAS | LIFETIME_PARAM | TYPE_PARAM | WHERE_PRED
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasTypeBounds { syntax })
@@ -4071,13 +4117,26 @@ impl AnyHasVisibility {
 }
 impl AstNode for AnyHasVisibility {
     fn can_cast(kind: SyntaxKind) -> bool {
-        match kind {
-            CONST | ENUM | EXTERN_CRATE | FN | IMPL | MACRO_RULES | MACRO_DEF | MODULE | STATIC
-            | STRUCT | TRAIT | TYPE_ALIAS | UNION | USE | RECORD_FIELD | TUPLE_FIELD | VARIANT => {
-                true
-            }
-            _ => false,
-        }
+        matches!(
+            kind,
+            CONST
+                | ENUM
+                | EXTERN_CRATE
+                | FN
+                | IMPL
+                | MACRO_RULES
+                | MACRO_DEF
+                | MODULE
+                | STATIC
+                | STRUCT
+                | TRAIT
+                | TYPE_ALIAS
+                | UNION
+                | USE
+                | RECORD_FIELD
+                | TUPLE_FIELD
+                | VARIANT
+        )
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         Self::can_cast(syntax.kind()).then(|| AnyHasVisibility { syntax })
diff --git a/src/tools/rust-analyzer/crates/syntax/src/ast/make.rs b/src/tools/rust-analyzer/crates/syntax/src/ast/make.rs
index 037de876d45c..83f8bbac5880 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/ast/make.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/ast/make.rs
@@ -25,7 +25,7 @@ pub mod ext {
         return from_text(&name.text());
 
         fn from_text(text: &str) -> ast::IdentPat {
-            ast_from_text(&format!("fn f({}: ())", text))
+            ast_from_text(&format!("fn f({text}: ())"))
         }
     }
     pub fn ident_path(ident: &str) -> ast::Path {
@@ -60,10 +60,10 @@ pub mod ext {
         expr_from_text("todo!()")
     }
     pub fn expr_ty_default(ty: &ast::Type) -> ast::Expr {
-        expr_from_text(&format!("{}::default()", ty))
+        expr_from_text(&format!("{ty}::default()"))
     }
     pub fn expr_ty_new(ty: &ast::Type) -> ast::Expr {
-        expr_from_text(&format!("{}::new()", ty))
+        expr_from_text(&format!("{ty}::new()"))
     }
 
     pub fn zero_number() -> ast::Expr {
@@ -92,18 +92,20 @@ pub mod ext {
         ty_path(ident_path("bool"))
     }
     pub fn ty_option(t: ast::Type) -> ast::Type {
-        ty_from_text(&format!("Option<{}>", t))
+        ty_from_text(&format!("Option<{t}>"))
     }
     pub fn ty_result(t: ast::Type, e: ast::Type) -> ast::Type {
-        ty_from_text(&format!("Result<{}, {}>", t, e))
+        ty_from_text(&format!("Result<{t}, {e}>"))
     }
 }
 
-pub fn name(text: &str) -> ast::Name {
-    ast_from_text(&format!("mod {}{};", raw_ident_esc(text), text))
+pub fn name(name: &str) -> ast::Name {
+    let raw_escape = raw_ident_esc(name);
+    ast_from_text(&format!("mod {raw_escape}{name};"))
 }
-pub fn name_ref(text: &str) -> ast::NameRef {
-    ast_from_text(&format!("fn f() {{ {}{}; }}", raw_ident_esc(text), text))
+pub fn name_ref(name_ref: &str) -> ast::NameRef {
+    let raw_escape = raw_ident_esc(name_ref);
+    ast_from_text(&format!("fn f() {{ {raw_escape}{name_ref}; }}"))
 }
 fn raw_ident_esc(ident: &str) -> &'static str {
     let is_keyword = parser::SyntaxKind::from_keyword(ident).is_some();
@@ -118,10 +120,10 @@ pub fn lifetime(text: &str) -> ast::Lifetime {
     let mut text = text;
     let tmp;
     if never!(!text.starts_with('\'')) {
-        tmp = format!("'{}", text);
+        tmp = format!("'{text}");
         text = &tmp;
     }
-    ast_from_text(&format!("fn f<{}>() {{ }}", text))
+    ast_from_text(&format!("fn f<{text}>() {{ }}"))
 }
 
 // FIXME: replace stringly-typed constructor with a family of typed ctors, a-la
@@ -142,16 +144,16 @@ pub fn ty_tuple(types: impl IntoIterator<Item = ast::Type>) -> ast::Type {
         contents.push(',');
     }
 
-    ty_from_text(&format!("({})", contents))
+    ty_from_text(&format!("({contents})"))
 }
 pub fn ty_ref(target: ast::Type, exclusive: bool) -> ast::Type {
-    ty_from_text(&if exclusive { format!("&mut {}", target) } else { format!("&{}", target) })
+    ty_from_text(&if exclusive { format!("&mut {target}") } else { format!("&{target}") })
 }
 pub fn ty_path(path: ast::Path) -> ast::Type {
     ty_from_text(&path.to_string())
 }
 fn ty_from_text(text: &str) -> ast::Type {
-    ast_from_text(&format!("type _T = {};", text))
+    ast_from_text(&format!("type _T = {text};"))
 }
 
 pub fn assoc_item_list() -> ast::AssocItemList {
@@ -171,7 +173,7 @@ pub fn impl_(
         Some(params) => params.to_string(),
         None => String::new(),
     };
-    ast_from_text(&format!("impl{} {}{} {{}}", params, ty, ty_params))
+    ast_from_text(&format!("impl{params} {ty}{ty_params} {{}}"))
 }
 
 pub fn impl_trait(
@@ -180,7 +182,7 @@ pub fn impl_trait(
     ty_params: Option<ast::GenericParamList>,
 ) -> ast::Impl {
     let ty_params = ty_params.map_or_else(String::new, |params| params.to_string());
-    ast_from_text(&format!("impl{2} {} for {}{2} {{}}", trait_, ty, ty_params))
+    ast_from_text(&format!("impl{ty_params} {trait_} for {ty}{ty_params} {{}}"))
 }
 
 pub(crate) fn generic_arg_list() -> ast::GenericArgList {
@@ -188,13 +190,13 @@ pub(crate) fn generic_arg_list() -> ast::GenericArgList {
 }
 
 pub fn path_segment(name_ref: ast::NameRef) -> ast::PathSegment {
-    ast_from_text(&format!("type __ = {};", name_ref))
+    ast_from_text(&format!("type __ = {name_ref};"))
 }
 
 pub fn path_segment_ty(type_ref: ast::Type, trait_ref: Option<ast::PathType>) -> ast::PathSegment {
     let text = match trait_ref {
-        Some(trait_ref) => format!("fn f(x: <{} as {}>) {{}}", type_ref, trait_ref),
-        None => format!("fn f(x: <{}>) {{}}", type_ref),
+        Some(trait_ref) => format!("fn f(x: <{type_ref} as {trait_ref}>) {{}}"),
+        None => format!("fn f(x: <{type_ref}>) {{}}"),
     };
     ast_from_text(&text)
 }
@@ -212,15 +214,15 @@ pub fn path_segment_crate() -> ast::PathSegment {
 }
 
 pub fn path_unqualified(segment: ast::PathSegment) -> ast::Path {
-    ast_from_text(&format!("type __ = {};", segment))
+    ast_from_text(&format!("type __ = {segment};"))
 }
 
 pub fn path_qualified(qual: ast::Path, segment: ast::PathSegment) -> ast::Path {
-    ast_from_text(&format!("{}::{}", qual, segment))
+    ast_from_text(&format!("{qual}::{segment}"))
 }
 // FIXME: path concatenation operation doesn't make sense as AST op.
 pub fn path_concat(first: ast::Path, second: ast::Path) -> ast::Path {
-    ast_from_text(&format!("type __ = {}::{};", first, second))
+    ast_from_text(&format!("type __ = {first}::{second};"))
 }
 
 pub fn path_from_segments(
@@ -229,20 +231,20 @@ pub fn path_from_segments(
 ) -> ast::Path {
     let segments = segments.into_iter().map(|it| it.syntax().clone()).join("::");
     ast_from_text(&if is_abs {
-        format!("fn f(x: ::{}) {{}}", segments)
+        format!("fn f(x: ::{segments}) {{}}")
     } else {
-        format!("fn f(x: {}) {{}}", segments)
+        format!("fn f(x: {segments}) {{}}")
     })
 }
 
 pub fn join_paths(paths: impl IntoIterator<Item = ast::Path>) -> ast::Path {
     let paths = paths.into_iter().map(|it| it.syntax().clone()).join("::");
-    ast_from_text(&format!("type __ = {};", paths))
+    ast_from_text(&format!("type __ = {paths};"))
 }
 
 // FIXME: should not be pub
 pub fn path_from_text(text: &str) -> ast::Path {
-    ast_from_text(&format!("fn main() {{ let test = {}; }}", text))
+    ast_from_text(&format!("fn main() {{ let test = {text}; }}"))
 }
 
 pub fn use_tree_glob() -> ast::UseTree {
@@ -257,50 +259,50 @@ pub fn use_tree(
     let mut buf = "use ".to_string();
     buf += &path.syntax().to_string();
     if let Some(use_tree_list) = use_tree_list {
-        format_to!(buf, "::{}", use_tree_list);
+        format_to!(buf, "::{use_tree_list}");
     }
     if add_star {
         buf += "::*";
     }
 
     if let Some(alias) = alias {
-        format_to!(buf, " {}", alias);
+        format_to!(buf, " {alias}");
     }
     ast_from_text(&buf)
 }
 
 pub fn use_tree_list(use_trees: impl IntoIterator<Item = ast::UseTree>) -> ast::UseTreeList {
     let use_trees = use_trees.into_iter().map(|it| it.syntax().clone()).join(", ");
-    ast_from_text(&format!("use {{{}}};", use_trees))
+    ast_from_text(&format!("use {{{use_trees}}};"))
 }
 
 pub fn use_(visibility: Option<ast::Visibility>, use_tree: ast::UseTree) -> ast::Use {
     let visibility = match visibility {
         None => String::new(),
-        Some(it) => format!("{} ", it),
+        Some(it) => format!("{it} "),
     };
-    ast_from_text(&format!("{}use {};", visibility, use_tree))
+    ast_from_text(&format!("{visibility}use {use_tree};"))
 }
 
 pub fn record_expr(path: ast::Path, fields: ast::RecordExprFieldList) -> ast::RecordExpr {
-    ast_from_text(&format!("fn f() {{ {} {} }}", path, fields))
+    ast_from_text(&format!("fn f() {{ {path} {fields} }}"))
 }
 
 pub fn record_expr_field_list(
     fields: impl IntoIterator<Item = ast::RecordExprField>,
 ) -> ast::RecordExprFieldList {
     let fields = fields.into_iter().join(", ");
-    ast_from_text(&format!("fn f() {{ S {{ {} }} }}", fields))
+    ast_from_text(&format!("fn f() {{ S {{ {fields} }} }}"))
 }
 
 pub fn record_expr_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::RecordExprField {
     return match expr {
-        Some(expr) => from_text(&format!("{}: {}", name, expr)),
+        Some(expr) => from_text(&format!("{name}: {expr}")),
         None => from_text(&name.to_string()),
     };
 
     fn from_text(text: &str) -> ast::RecordExprField {
-        ast_from_text(&format!("fn f() {{ S {{ {}, }} }}", text))
+        ast_from_text(&format!("fn f() {{ S {{ {text}, }} }}"))
     }
 }
 
@@ -311,9 +313,9 @@ pub fn record_field(
 ) -> ast::RecordField {
     let visibility = match visibility {
         None => String::new(),
-        Some(it) => format!("{} ", it),
+        Some(it) => format!("{it} "),
     };
-    ast_from_text(&format!("struct S {{ {}{}: {}, }}", visibility, name, ty))
+    ast_from_text(&format!("struct S {{ {visibility}{name}: {ty}, }}"))
 }
 
 // TODO
@@ -323,13 +325,13 @@ pub fn block_expr(
 ) -> ast::BlockExpr {
     let mut buf = "{\n".to_string();
     for stmt in stmts.into_iter() {
-        format_to!(buf, "    {}\n", stmt);
+        format_to!(buf, "    {stmt}\n");
     }
     if let Some(tail_expr) = tail_expr {
-        format_to!(buf, "    {}\n", tail_expr);
+        format_to!(buf, "    {tail_expr}\n");
     }
     buf += "}";
-    ast_from_text(&format!("fn f() {}", buf))
+    ast_from_text(&format!("fn f() {buf}"))
 }
 
 /// Ideally this function wouldn't exist since it involves manual indenting.
@@ -343,18 +345,18 @@ pub fn hacky_block_expr_with_comments(
     let mut buf = "{\n".to_string();
     for node_or_token in elements.into_iter() {
         match node_or_token {
-            rowan::NodeOrToken::Node(n) => format_to!(buf, "    {}\n", n),
+            rowan::NodeOrToken::Node(n) => format_to!(buf, "    {n}\n"),
             rowan::NodeOrToken::Token(t) if t.kind() == SyntaxKind::COMMENT => {
-                format_to!(buf, "    {}\n", t)
+                format_to!(buf, "    {t}\n")
             }
             _ => (),
         }
     }
     if let Some(tail_expr) = tail_expr {
-        format_to!(buf, "    {}\n", tail_expr);
+        format_to!(buf, "    {tail_expr}\n");
     }
     buf += "}";
-    ast_from_text(&format!("fn f() {}", buf))
+    ast_from_text(&format!("fn f() {buf}"))
 }
 
 pub fn expr_unit() -> ast::Expr {
@@ -362,7 +364,7 @@ pub fn expr_unit() -> ast::Expr {
 }
 pub fn expr_literal(text: &str) -> ast::Literal {
     assert_eq!(text.trim(), text);
-    ast_from_text(&format!("fn f() {{ let _ = {}; }}", text))
+    ast_from_text(&format!("fn f() {{ let _ = {text}; }}"))
 }
 
 pub fn expr_empty_block() -> ast::Expr {
@@ -373,41 +375,41 @@ pub fn expr_path(path: ast::Path) -> ast::Expr {
 }
 pub fn expr_continue(label: Option<ast::Lifetime>) -> ast::Expr {
     match label {
-        Some(label) => expr_from_text(&format!("continue {}", label)),
+        Some(label) => expr_from_text(&format!("continue {label}")),
         None => expr_from_text("continue"),
     }
 }
 // Consider `op: SyntaxKind` instead for nicer syntax at the call-site?
 pub fn expr_bin_op(lhs: ast::Expr, op: ast::BinaryOp, rhs: ast::Expr) -> ast::Expr {
-    expr_from_text(&format!("{} {} {}", lhs, op, rhs))
+    expr_from_text(&format!("{lhs} {op} {rhs}"))
 }
 pub fn expr_break(label: Option<ast::Lifetime>, expr: Option<ast::Expr>) -> ast::Expr {
     let mut s = String::from("break");
 
     if let Some(label) = label {
-        format_to!(s, " {}", label);
+        format_to!(s, " {label}");
     }
 
     if let Some(expr) = expr {
-        format_to!(s, " {}", expr);
+        format_to!(s, " {expr}");
     }
 
     expr_from_text(&s)
 }
 pub fn expr_return(expr: Option<ast::Expr>) -> ast::Expr {
     match expr {
-        Some(expr) => expr_from_text(&format!("return {}", expr)),
+        Some(expr) => expr_from_text(&format!("return {expr}")),
         None => expr_from_text("return"),
     }
 }
 pub fn expr_try(expr: ast::Expr) -> ast::Expr {
-    expr_from_text(&format!("{}?", expr))
+    expr_from_text(&format!("{expr}?"))
 }
 pub fn expr_await(expr: ast::Expr) -> ast::Expr {
-    expr_from_text(&format!("{}.await", expr))
+    expr_from_text(&format!("{expr}.await"))
 }
 pub fn expr_match(expr: ast::Expr, match_arm_list: ast::MatchArmList) -> ast::Expr {
-    expr_from_text(&format!("match {} {}", expr, match_arm_list))
+    expr_from_text(&format!("match {expr} {match_arm_list}"))
 }
 pub fn expr_if(
     condition: ast::Expr,
@@ -415,66 +417,67 @@ pub fn expr_if(
     else_branch: Option<ast::ElseBranch>,
 ) -> ast::Expr {
     let else_branch = match else_branch {
-        Some(ast::ElseBranch::Block(block)) => format!("else {}", block),
-        Some(ast::ElseBranch::IfExpr(if_expr)) => format!("else {}", if_expr),
+        Some(ast::ElseBranch::Block(block)) => format!("else {block}"),
+        Some(ast::ElseBranch::IfExpr(if_expr)) => format!("else {if_expr}"),
         None => String::new(),
     };
-    expr_from_text(&format!("if {} {} {}", condition, then_branch, else_branch))
+    expr_from_text(&format!("if {condition} {then_branch} {else_branch}"))
 }
 pub fn expr_for_loop(pat: ast::Pat, expr: ast::Expr, block: ast::BlockExpr) -> ast::Expr {
-    expr_from_text(&format!("for {} in {} {}", pat, expr, block))
+    expr_from_text(&format!("for {pat} in {expr} {block}"))
 }
 
 pub fn expr_loop(block: ast::BlockExpr) -> ast::Expr {
-    expr_from_text(&format!("loop {}", block))
+    expr_from_text(&format!("loop {block}"))
 }
 
 pub fn expr_prefix(op: SyntaxKind, expr: ast::Expr) -> ast::Expr {
     let token = token(op);
-    expr_from_text(&format!("{}{}", token, expr))
+    expr_from_text(&format!("{token}{expr}"))
 }
 pub fn expr_call(f: ast::Expr, arg_list: ast::ArgList) -> ast::Expr {
-    expr_from_text(&format!("{}{}", f, arg_list))
+    expr_from_text(&format!("{f}{arg_list}"))
 }
 pub fn expr_method_call(
     receiver: ast::Expr,
     method: ast::NameRef,
     arg_list: ast::ArgList,
 ) -> ast::Expr {
-    expr_from_text(&format!("{}.{}{}", receiver, method, arg_list))
+    expr_from_text(&format!("{receiver}.{method}{arg_list}"))
 }
 pub fn expr_macro_call(f: ast::Expr, arg_list: ast::ArgList) -> ast::Expr {
-    expr_from_text(&format!("{}!{}", f, arg_list))
+    expr_from_text(&format!("{f}!{arg_list}"))
 }
 pub fn expr_ref(expr: ast::Expr, exclusive: bool) -> ast::Expr {
-    expr_from_text(&if exclusive { format!("&mut {}", expr) } else { format!("&{}", expr) })
+    expr_from_text(&if exclusive { format!("&mut {expr}") } else { format!("&{expr}") })
 }
 pub fn expr_closure(pats: impl IntoIterator<Item = ast::Param>, expr: ast::Expr) -> ast::Expr {
     let params = pats.into_iter().join(", ");
-    expr_from_text(&format!("|{}| {}", params, expr))
+    expr_from_text(&format!("|{params}| {expr}"))
 }
 pub fn expr_field(receiver: ast::Expr, field: &str) -> ast::Expr {
-    expr_from_text(&format!("{}.{}", receiver, field))
+    expr_from_text(&format!("{receiver}.{field}"))
 }
 pub fn expr_paren(expr: ast::Expr) -> ast::Expr {
-    expr_from_text(&format!("({})", expr))
+    expr_from_text(&format!("({expr})"))
 }
 pub fn expr_tuple(elements: impl IntoIterator<Item = ast::Expr>) -> ast::Expr {
     let expr = elements.into_iter().format(", ");
-    expr_from_text(&format!("({})", expr))
+    expr_from_text(&format!("({expr})"))
 }
 pub fn expr_assignment(lhs: ast::Expr, rhs: ast::Expr) -> ast::Expr {
-    expr_from_text(&format!("{} = {}", lhs, rhs))
+    expr_from_text(&format!("{lhs} = {rhs}"))
 }
 fn expr_from_text(text: &str) -> ast::Expr {
-    ast_from_text(&format!("const C: () = {};", text))
+    ast_from_text(&format!("const C: () = {text};"))
 }
 pub fn expr_let(pattern: ast::Pat, expr: ast::Expr) -> ast::LetExpr {
-    ast_from_text(&format!("const _: () = while let {} = {} {{}};", pattern, expr))
+    ast_from_text(&format!("const _: () = while let {pattern} = {expr} {{}};"))
 }
 
 pub fn arg_list(args: impl IntoIterator<Item = ast::Expr>) -> ast::ArgList {
-    ast_from_text(&format!("fn main() {{ ()({}) }}", args.into_iter().format(", ")))
+    let args = args.into_iter().format(", ");
+    ast_from_text(&format!("fn main() {{ ()({args}) }}"))
 }
 
 pub fn ident_pat(ref_: bool, mut_: bool, name: ast::Name) -> ast::IdentPat {
@@ -485,7 +488,7 @@ pub fn ident_pat(ref_: bool, mut_: bool, name: ast::Name) -> ast::IdentPat {
     if mut_ {
         s.push_str("mut ");
     }
-    format_to!(s, "{}", name);
+    format_to!(s, "{name}");
     s.push_str(": ())");
     ast_from_text(&s)
 }
@@ -494,7 +497,7 @@ pub fn wildcard_pat() -> ast::WildcardPat {
     return from_text("_");
 
     fn from_text(text: &str) -> ast::WildcardPat {
-        ast_from_text(&format!("fn f({}: ())", text))
+        ast_from_text(&format!("fn f({text}: ())"))
     }
 }
 
@@ -502,7 +505,7 @@ pub fn literal_pat(lit: &str) -> ast::LiteralPat {
     return from_text(lit);
 
     fn from_text(text: &str) -> ast::LiteralPat {
-        ast_from_text(&format!("fn f() {{ match x {{ {} => {{}} }} }}", text))
+        ast_from_text(&format!("fn f() {{ match x {{ {text} => {{}} }} }}"))
     }
 }
 
@@ -515,10 +518,10 @@ pub fn tuple_pat(pats: impl IntoIterator<Item = ast::Pat>) -> ast::TuplePat {
     if count == 1 {
         pats_str.push(',');
     }
-    return from_text(&format!("({})", pats_str));
+    return from_text(&format!("({pats_str})"));
 
     fn from_text(text: &str) -> ast::TuplePat {
-        ast_from_text(&format!("fn f({}: ())", text))
+        ast_from_text(&format!("fn f({text}: ())"))
     }
 }
 
@@ -527,46 +530,46 @@ pub fn tuple_struct_pat(
     pats: impl IntoIterator<Item = ast::Pat>,
 ) -> ast::TupleStructPat {
     let pats_str = pats.into_iter().join(", ");
-    return from_text(&format!("{}({})", path, pats_str));
+    return from_text(&format!("{path}({pats_str})"));
 
     fn from_text(text: &str) -> ast::TupleStructPat {
-        ast_from_text(&format!("fn f({}: ())", text))
+        ast_from_text(&format!("fn f({text}: ())"))
     }
 }
 
 pub fn record_pat(path: ast::Path, pats: impl IntoIterator<Item = ast::Pat>) -> ast::RecordPat {
     let pats_str = pats.into_iter().join(", ");
-    return from_text(&format!("{} {{ {} }}", path, pats_str));
+    return from_text(&format!("{path} {{ {pats_str} }}"));
 
     fn from_text(text: &str) -> ast::RecordPat {
-        ast_from_text(&format!("fn f({}: ())", text))
+        ast_from_text(&format!("fn f({text}: ())"))
     }
 }
 
 pub fn record_pat_with_fields(path: ast::Path, fields: ast::RecordPatFieldList) -> ast::RecordPat {
-    ast_from_text(&format!("fn f({} {}: ()))", path, fields))
+    ast_from_text(&format!("fn f({path} {fields}: ()))"))
 }
 
 pub fn record_pat_field_list(
     fields: impl IntoIterator<Item = ast::RecordPatField>,
 ) -> ast::RecordPatFieldList {
     let fields = fields.into_iter().join(", ");
-    ast_from_text(&format!("fn f(S {{ {} }}: ()))", fields))
+    ast_from_text(&format!("fn f(S {{ {fields} }}: ()))"))
 }
 
 pub fn record_pat_field(name_ref: ast::NameRef, pat: ast::Pat) -> ast::RecordPatField {
-    ast_from_text(&format!("fn f(S {{ {}: {} }}: ()))", name_ref, pat))
+    ast_from_text(&format!("fn f(S {{ {name_ref}: {pat} }}: ()))"))
 }
 
 pub fn record_pat_field_shorthand(name_ref: ast::NameRef) -> ast::RecordPatField {
-    ast_from_text(&format!("fn f(S {{ {} }}: ()))", name_ref))
+    ast_from_text(&format!("fn f(S {{ {name_ref} }}: ()))"))
 }
 
 /// Returns a `BindPat` if the path has just one segment, a `PathPat` otherwise.
 pub fn path_pat(path: ast::Path) -> ast::Pat {
     return from_text(&path.to_string());
     fn from_text(text: &str) -> ast::Pat {
-        ast_from_text(&format!("fn f({}: ())", text))
+        ast_from_text(&format!("fn f({text}: ())"))
     }
 }
 
@@ -577,12 +580,12 @@ pub fn match_arm(
 ) -> ast::MatchArm {
     let pats_str = pats.into_iter().join(" | ");
     return match guard {
-        Some(guard) => from_text(&format!("{} if {} => {}", pats_str, guard, expr)),
-        None => from_text(&format!("{} => {}", pats_str, expr)),
+        Some(guard) => from_text(&format!("{pats_str} if {guard} => {expr}")),
+        None => from_text(&format!("{pats_str} => {expr}")),
     };
 
     fn from_text(text: &str) -> ast::MatchArm {
-        ast_from_text(&format!("fn f() {{ match () {{{}}} }}", text))
+        ast_from_text(&format!("fn f() {{ match () {{{text}}} }}"))
     }
 }
 
@@ -592,10 +595,10 @@ pub fn match_arm_with_guard(
     expr: ast::Expr,
 ) -> ast::MatchArm {
     let pats_str = pats.into_iter().join(" | ");
-    return from_text(&format!("{} if {} => {}", pats_str, guard, expr));
+    return from_text(&format!("{pats_str} if {guard} => {expr}"));
 
     fn from_text(text: &str) -> ast::MatchArm {
-        ast_from_text(&format!("fn f() {{ match () {{{}}} }}", text))
+        ast_from_text(&format!("fn f() {{ match () {{{text}}} }}"))
     }
 }
 
@@ -605,13 +608,14 @@ pub fn match_arm_list(arms: impl IntoIterator<Item = ast::MatchArm>) -> ast::Mat
         .map(|arm| {
             let needs_comma = arm.expr().map_or(true, |it| !it.is_block_like());
             let comma = if needs_comma { "," } else { "" };
-            format!("    {}{}\n", arm.syntax(), comma)
+            let arm = arm.syntax();
+            format!("    {arm}{comma}\n")
         })
         .collect::<String>();
     return from_text(&arms_str);
 
     fn from_text(text: &str) -> ast::MatchArmList {
-        ast_from_text(&format!("fn f() {{ match () {{\n{}}} }}", text))
+        ast_from_text(&format!("fn f() {{ match () {{\n{text}}} }}"))
     }
 }
 
@@ -620,10 +624,10 @@ pub fn where_pred(
     bounds: impl IntoIterator<Item = ast::TypeBound>,
 ) -> ast::WherePred {
     let bounds = bounds.into_iter().join(" + ");
-    return from_text(&format!("{}: {}", path, bounds));
+    return from_text(&format!("{path}: {bounds}"));
 
     fn from_text(text: &str) -> ast::WherePred {
-        ast_from_text(&format!("fn f() where {} {{ }}", text))
+        ast_from_text(&format!("fn f() where {text} {{ }}"))
     }
 }
 
@@ -632,7 +636,7 @@ pub fn where_clause(preds: impl IntoIterator<Item = ast::WherePred>) -> ast::Whe
     return from_text(preds.as_str());
 
     fn from_text(text: &str) -> ast::WhereClause {
-        ast_from_text(&format!("fn f() where {} {{ }}", text))
+        ast_from_text(&format!("fn f() where {text} {{ }}"))
     }
 }
 
@@ -642,19 +646,19 @@ pub fn let_stmt(
     initializer: Option<ast::Expr>,
 ) -> ast::LetStmt {
     let mut text = String::new();
-    format_to!(text, "let {}", pattern);
+    format_to!(text, "let {pattern}");
     if let Some(ty) = ty {
-        format_to!(text, ": {}", ty);
+        format_to!(text, ": {ty}");
     }
     match initializer {
-        Some(it) => format_to!(text, " = {};", it),
+        Some(it) => format_to!(text, " = {it};"),
         None => format_to!(text, ";"),
     };
-    ast_from_text(&format!("fn f() {{ {} }}", text))
+    ast_from_text(&format!("fn f() {{ {text} }}"))
 }
 pub fn expr_stmt(expr: ast::Expr) -> ast::ExprStmt {
     let semi = if expr.is_block_like() { "" } else { ";" };
-    ast_from_text(&format!("fn f() {{ {}{} (); }}", expr, semi))
+    ast_from_text(&format!("fn f() {{ {expr}{semi} (); }}"))
 }
 
 pub fn item_const(
@@ -665,13 +669,13 @@ pub fn item_const(
 ) -> ast::Const {
     let visibility = match visibility {
         None => String::new(),
-        Some(it) => format!("{} ", it),
+        Some(it) => format!("{it} "),
     };
-    ast_from_text(&format!("{} const {}: {} = {};", visibility, name, ty, expr))
+    ast_from_text(&format!("{visibility} const {name}: {ty} = {expr};"))
 }
 
 pub fn param(pat: ast::Pat, ty: ast::Type) -> ast::Param {
-    ast_from_text(&format!("fn f({}: {}) {{ }}", pat, ty))
+    ast_from_text(&format!("fn f({pat}: {ty}) {{ }}"))
 }
 
 pub fn self_param() -> ast::SelfParam {
@@ -679,7 +683,7 @@ pub fn self_param() -> ast::SelfParam {
 }
 
 pub fn ret_type(ty: ast::Type) -> ast::RetType {
-    ast_from_text(&format!("fn f() -> {} {{ }}", ty))
+    ast_from_text(&format!("fn f() -> {ty} {{ }}"))
 }
 
 pub fn param_list(
@@ -688,30 +692,30 @@ pub fn param_list(
 ) -> ast::ParamList {
     let args = pats.into_iter().join(", ");
     let list = match self_param {
-        Some(self_param) if args.is_empty() => format!("fn f({}) {{ }}", self_param),
-        Some(self_param) => format!("fn f({}, {}) {{ }}", self_param, args),
-        None => format!("fn f({}) {{ }}", args),
+        Some(self_param) if args.is_empty() => format!("fn f({self_param}) {{ }}"),
+        Some(self_param) => format!("fn f({self_param}, {args}) {{ }}"),
+        None => format!("fn f({args}) {{ }}"),
     };
     ast_from_text(&list)
 }
 
 pub fn type_param(name: ast::Name, ty: Option<ast::TypeBoundList>) -> ast::TypeParam {
     let bound = match ty {
-        Some(it) => format!(": {}", it),
+        Some(it) => format!(": {it}"),
         None => String::new(),
     };
-    ast_from_text(&format!("fn f<{}{}>() {{ }}", name, bound))
+    ast_from_text(&format!("fn f<{name}{bound}>() {{ }}"))
 }
 
 pub fn lifetime_param(lifetime: ast::Lifetime) -> ast::LifetimeParam {
-    ast_from_text(&format!("fn f<{}>() {{ }}", lifetime))
+    ast_from_text(&format!("fn f<{lifetime}>() {{ }}"))
 }
 
 pub fn generic_param_list(
     pats: impl IntoIterator<Item = ast::GenericParam>,
 ) -> ast::GenericParamList {
     let args = pats.into_iter().join(", ");
-    ast_from_text(&format!("fn f<{}>() {{ }}", args))
+    ast_from_text(&format!("fn f<{args}>() {{ }}"))
 }
 
 pub fn visibility_pub_crate() -> ast::Visibility {
@@ -724,33 +728,33 @@ pub fn visibility_pub() -> ast::Visibility {
 
 pub fn tuple_field_list(fields: impl IntoIterator<Item = ast::TupleField>) -> ast::TupleFieldList {
     let fields = fields.into_iter().join(", ");
-    ast_from_text(&format!("struct f({});", fields))
+    ast_from_text(&format!("struct f({fields});"))
 }
 
 pub fn record_field_list(
     fields: impl IntoIterator<Item = ast::RecordField>,
 ) -> ast::RecordFieldList {
     let fields = fields.into_iter().join(", ");
-    ast_from_text(&format!("struct f {{ {} }}", fields))
+    ast_from_text(&format!("struct f {{ {fields} }}"))
 }
 
 pub fn tuple_field(visibility: Option<ast::Visibility>, ty: ast::Type) -> ast::TupleField {
     let visibility = match visibility {
         None => String::new(),
-        Some(it) => format!("{} ", it),
+        Some(it) => format!("{it} "),
     };
-    ast_from_text(&format!("struct f({}{});", visibility, ty))
+    ast_from_text(&format!("struct f({visibility}{ty});"))
 }
 
 pub fn variant(name: ast::Name, field_list: Option<ast::FieldList>) -> ast::Variant {
     let field_list = match field_list {
         None => String::new(),
         Some(it) => match it {
-            ast::FieldList::RecordFieldList(record) => format!(" {}", record),
-            ast::FieldList::TupleFieldList(tuple) => format!("{}", tuple),
+            ast::FieldList::RecordFieldList(record) => format!(" {record}"),
+            ast::FieldList::TupleFieldList(tuple) => format!("{tuple}"),
         },
     };
-    ast_from_text(&format!("enum f {{ {}{} }}", name, field_list))
+    ast_from_text(&format!("enum f {{ {name}{field_list} }}"))
 }
 
 pub fn fn_(
@@ -763,23 +767,22 @@ pub fn fn_(
     is_async: bool,
 ) -> ast::Fn {
     let type_params = match type_params {
-        Some(type_params) => format!("{}", type_params),
+        Some(type_params) => format!("{type_params}"),
         None => "".into(),
     };
     let ret_type = match ret_type {
-        Some(ret_type) => format!("{} ", ret_type),
+        Some(ret_type) => format!("{ret_type} "),
         None => "".into(),
     };
     let visibility = match visibility {
         None => String::new(),
-        Some(it) => format!("{} ", it),
+        Some(it) => format!("{it} "),
     };
 
     let async_literal = if is_async { "async " } else { "" };
 
     ast_from_text(&format!(
-        "{}{}fn {}{}{} {}{}",
-        visibility, async_literal, fn_name, type_params, params, ret_type, body
+        "{visibility}{async_literal}fn {fn_name}{type_params}{params} {ret_type}{body}",
     ))
 }
 
@@ -793,13 +796,10 @@ pub fn struct_(
     let type_params = generic_param_list.map_or_else(String::new, |it| it.to_string());
     let visibility = match visibility {
         None => String::new(),
-        Some(it) => format!("{} ", it),
+        Some(it) => format!("{it} "),
     };
 
-    ast_from_text(&format!(
-        "{}struct {}{}{}{}",
-        visibility, strukt_name, type_params, field_list, semicolon
-    ))
+    ast_from_text(&format!("{visibility}struct {strukt_name}{type_params}{field_list}{semicolon}",))
 }
 
 #[track_caller]
@@ -808,7 +808,8 @@ fn ast_from_text<N: AstNode>(text: &str) -> N {
     let node = match parse.tree().syntax().descendants().find_map(N::cast) {
         Some(it) => it,
         None => {
-            panic!("Failed to make ast node `{}` from text {}", std::any::type_name::<N>(), text)
+            let node = std::any::type_name::<N>();
+            panic!("Failed to make ast node `{node}` from text {text}")
         }
     };
     let node = node.clone_subtree();
@@ -824,7 +825,7 @@ pub fn token(kind: SyntaxKind) -> SyntaxToken {
         .descendants_with_tokens()
         .filter_map(|it| it.into_token())
         .find(|it| it.kind() == kind)
-        .unwrap_or_else(|| panic!("unhandled token: {:?}", kind))
+        .unwrap_or_else(|| panic!("unhandled token: {kind:?}"))
 }
 
 pub mod tokens {
@@ -863,7 +864,7 @@ pub mod tokens {
 
     pub fn literal(text: &str) -> SyntaxToken {
         assert_eq!(text.trim(), text);
-        let lit: ast::Literal = super::ast_from_text(&format!("fn f() {{ let _ = {}; }}", text));
+        let lit: ast::Literal = super::ast_from_text(&format!("fn f() {{ let _ = {text}; }}"));
         lit.syntax().first_child_or_token().unwrap().into_token().unwrap()
     }
 
diff --git a/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs b/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs
index 28976d837b88..ba72e64425b2 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/ast/token_ext.rs
@@ -322,7 +322,7 @@ impl ast::IntNumber {
 
     pub fn float_value(&self) -> Option<f64> {
         let (_, text, _) = self.split_into_parts();
-        text.parse::<f64>().ok()
+        text.replace('_', "").parse::<f64>().ok()
     }
 }
 
@@ -361,7 +361,7 @@ impl ast::FloatNumber {
 
     pub fn value(&self) -> Option<f64> {
         let (text, _) = self.split_into_parts();
-        text.parse::<f64>().ok()
+        text.replace('_', "").parse::<f64>().ok()
     }
 }
 
@@ -397,6 +397,15 @@ mod tests {
         assert_eq!(IntNumber { syntax: make::tokens::literal(lit) }.suffix(), expected.into());
     }
 
+    fn check_float_value(lit: &str, expected: impl Into<Option<f64>> + Copy) {
+        assert_eq!(FloatNumber { syntax: make::tokens::literal(lit) }.value(), expected.into());
+        assert_eq!(IntNumber { syntax: make::tokens::literal(lit) }.float_value(), expected.into());
+    }
+
+    fn check_int_value(lit: &str, expected: impl Into<Option<u128>>) {
+        assert_eq!(IntNumber { syntax: make::tokens::literal(lit) }.value(), expected.into());
+    }
+
     #[test]
     fn test_float_number_suffix() {
         check_float_suffix("123.0", None);
@@ -437,6 +446,14 @@ mod tests {
         check_string_value(r"\nfoobar", "\nfoobar");
         check_string_value(r"C:\\Windows\\System32\\", "C:\\Windows\\System32\\");
     }
+
+    #[test]
+    fn test_value_underscores() {
+        check_float_value("3.141592653589793_f64", 3.141592653589793_f64);
+        check_float_value("1__0.__0__f32", 10.0);
+        check_int_value("0b__1_0_", 2);
+        check_int_value("1_1_1_1_1_1", 111111);
+    }
 }
 
 impl ast::Char {
diff --git a/src/tools/rust-analyzer/crates/syntax/src/tests/sourcegen_ast.rs b/src/tools/rust-analyzer/crates/syntax/src/tests/sourcegen_ast.rs
index 6d2766225103..70b54843dbaa 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/tests/sourcegen_ast.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/tests/sourcegen_ast.rs
@@ -169,10 +169,7 @@ fn generate_nodes(kinds: KindsSrc<'_>, grammar: &AstSrc) -> String {
                 quote! {
                     impl AstNode for #name {
                         fn can_cast(kind: SyntaxKind) -> bool {
-                            match kind {
-                                #(#kinds)|* => true,
-                                _ => false,
-                            }
+                            matches!(kind, #(#kinds)|*)
                         }
                         fn cast(syntax: SyntaxNode) -> Option<Self> {
                             let res = match syntax.kind() {
@@ -253,10 +250,7 @@ fn generate_nodes(kinds: KindsSrc<'_>, grammar: &AstSrc) -> String {
                     }
                     impl AstNode for #name {
                         fn can_cast(kind: SyntaxKind) -> bool {
-                            match kind {
-                                #(#kinds)|* => true,
-                                _ => false,
-                            }
+                            matches!(kind, #(#kinds)|*)
                         }
                         fn cast(syntax: SyntaxNode) -> Option<Self> {
                             Self::can_cast(syntax.kind()).then(|| #name { syntax })
@@ -410,24 +404,17 @@ fn generate_syntax_kinds(grammar: KindsSrc<'_>) -> String {
 
         impl SyntaxKind {
             pub fn is_keyword(self) -> bool {
-                match self {
-                    #(#all_keywords)|* => true,
-                    _ => false,
-                }
+                matches!(self, #(#all_keywords)|*)
             }
 
             pub fn is_punct(self) -> bool {
-                match self {
-                    #(#punctuation)|* => true,
-                    _ => false,
-                }
+
+                matches!(self, #(#punctuation)|*)
+
             }
 
             pub fn is_literal(self) -> bool {
-                match self {
-                    #(#literals)|* => true,
-                    _ => false,
-                }
+                matches!(self, #(#literals)|*)
             }
 
             pub fn from_keyword(ident: &str) -> Option<SyntaxKind> {
diff --git a/src/tools/rust-analyzer/docs/user/generated_config.adoc b/src/tools/rust-analyzer/docs/user/generated_config.adoc
index 72b925726479..996d4c023d7b 100644
--- a/src/tools/rust-analyzer/docs/user/generated_config.adoc
+++ b/src/tools/rust-analyzer/docs/user/generated_config.adoc
@@ -46,6 +46,12 @@ cargo check --quiet --workspace --message-format=json --all-targets
 Use `RUSTC_WRAPPER=rust-analyzer` when running build scripts to
 avoid checking unnecessary things.
 --
+[[rust-analyzer.cargo.extraEnv]]rust-analyzer.cargo.extraEnv (default: `{}`)::
++
+--
+Extra environment variables that will be set when running cargo, rustc
+or other commands within the workspace. Useful for setting RUSTFLAGS.
+--
 [[rust-analyzer.cargo.features]]rust-analyzer.cargo.features (default: `[]`)::
 +
 --
@@ -93,6 +99,11 @@ Run specified `cargo check` command for diagnostics on save.
 --
 Extra arguments for `cargo check`.
 --
+[[rust-analyzer.checkOnSave.extraEnv]]rust-analyzer.checkOnSave.extraEnv (default: `{}`)::
++
+--
+Extra environment variables that will be set when running `cargo check`.
+--
 [[rust-analyzer.checkOnSave.features]]rust-analyzer.checkOnSave.features (default: `null`)::
 +
 --
@@ -353,6 +364,11 @@ Group inserted imports by the https://rust-analyzer.github.io/manual.html#auto-i
 --
 Whether to allow import insertion to merge new imports into single path glob imports like `use std::fmt::*;`.
 --
+[[rust-analyzer.imports.prefer.no.std]]rust-analyzer.imports.prefer.no.std (default: `false`)::
++
+--
+Prefer to unconditionally use imports of the core and alloc crate, over the std crate.
+--
 [[rust-analyzer.imports.prefix]]rust-analyzer.imports.prefix (default: `"plain"`)::
 +
 --
@@ -474,6 +490,11 @@ client doesn't set the corresponding capability.
 Whether to show `Implementations` lens. Only applies when
 `#rust-analyzer.lens.enable#` is set.
 --
+[[rust-analyzer.lens.location]]rust-analyzer.lens.location (default: `"above_name"`)::
++
+--
+Where to render annotations.
+--
 [[rust-analyzer.lens.references.adt.enable]]rust-analyzer.lens.references.adt.enable (default: `false`)::
 +
 --
@@ -546,6 +567,11 @@ This config takes a map of crate names with the exported proc-macro names to ign
 Internal config, path to proc-macro server executable (typically,
 this is rust-analyzer itself, but we override this in tests).
 --
+[[rust-analyzer.references.excludeImports]]rust-analyzer.references.excludeImports (default: `false`)::
++
+--
+Exclude imports from find-all-references.
+--
 [[rust-analyzer.runnables.command]]rust-analyzer.runnables.command (default: `null`)::
 +
 --
diff --git a/src/tools/rust-analyzer/editors/code/package.json b/src/tools/rust-analyzer/editors/code/package.json
index 767c5875bf7e..94b41c049bc3 100644
--- a/src/tools/rust-analyzer/editors/code/package.json
+++ b/src/tools/rust-analyzer/editors/code/package.json
@@ -206,11 +206,6 @@
                 "title": "Show RA Version",
                 "category": "rust-analyzer"
             },
-            {
-                "command": "rust-analyzer.toggleInlayHints",
-                "title": "Toggle inlay hints",
-                "category": "rust-analyzer"
-            },
             {
                 "command": "rust-analyzer.openDocs",
                 "title": "Open docs under cursor",
@@ -442,6 +437,11 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.cargo.extraEnv": {
+                    "markdownDescription": "Extra environment variables that will be set when running cargo, rustc\nor other commands within the workspace. Useful for setting RUSTFLAGS.",
+                    "default": {},
+                    "type": "object"
+                },
                 "rust-analyzer.cargo.features": {
                     "markdownDescription": "List of features to activate.\n\nSet this to `\"all\"` to pass `--all-features` to cargo.",
                     "default": [],
@@ -514,6 +514,11 @@
                         "type": "string"
                     }
                 },
+                "rust-analyzer.checkOnSave.extraEnv": {
+                    "markdownDescription": "Extra environment variables that will be set when running `cargo check`.",
+                    "default": {},
+                    "type": "object"
+                },
                 "rust-analyzer.checkOnSave.features": {
                     "markdownDescription": "List of features to activate. Defaults to\n`#rust-analyzer.cargo.features#`.\n\nSet to `\"all\"` to pass `--all-features` to Cargo.",
                     "default": null,
@@ -803,6 +808,11 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.imports.prefer.no.std": {
+                    "markdownDescription": "Prefer to unconditionally use imports of the core and alloc crate, over the std crate.",
+                    "default": false,
+                    "type": "boolean"
+                },
                 "rust-analyzer.imports.prefix": {
                     "markdownDescription": "The path structure for newly inserted paths to use.",
                     "default": "plain",
@@ -963,6 +973,19 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.lens.location": {
+                    "markdownDescription": "Where to render annotations.",
+                    "default": "above_name",
+                    "type": "string",
+                    "enum": [
+                        "above_name",
+                        "above_whole_item"
+                    ],
+                    "enumDescriptions": [
+                        "Render annotations above the name of the item.",
+                        "Render annotations above the whole item, including documentation comments and attributes."
+                    ]
+                },
                 "rust-analyzer.lens.references.adt.enable": {
                     "markdownDescription": "Whether to show `References` lens for Struct, Enum, and Union.\nOnly applies when `#rust-analyzer.lens.enable#` is set.",
                     "default": false,
@@ -1036,6 +1059,11 @@
                         "string"
                     ]
                 },
+                "rust-analyzer.references.excludeImports": {
+                    "markdownDescription": "Exclude imports from find-all-references.",
+                    "default": false,
+                    "type": "boolean"
+                },
                 "rust-analyzer.runnables.command": {
                     "markdownDescription": "Command to be executed instead of 'cargo' for runnables.",
                     "default": null,
@@ -1633,10 +1661,6 @@
                     "command": "rust-analyzer.serverVersion",
                     "when": "inRustProject"
                 },
-                {
-                    "command": "rust-analyzer.toggleInlayHints",
-                    "when": "inRustProject"
-                },
                 {
                     "command": "rust-analyzer.openDocs",
                     "when": "inRustProject"
diff --git a/src/tools/rust-analyzer/editors/code/src/commands.ts b/src/tools/rust-analyzer/editors/code/src/commands.ts
index a21b304bbdaa..b9ad525e361f 100644
--- a/src/tools/rust-analyzer/editors/code/src/commands.ts
+++ b/src/tools/rust-analyzer/editors/code/src/commands.ts
@@ -321,30 +321,6 @@ export function serverVersion(ctx: Ctx): Cmd {
     };
 }
 
-export function toggleInlayHints(_ctx: Ctx): Cmd {
-    return async () => {
-        const config = vscode.workspace.getConfiguration("editor.inlayHints", {
-            languageId: "rust",
-        });
-
-        const value = config.get("enabled");
-        let stringValue;
-        if (typeof value === "string") {
-            stringValue = value;
-        } else {
-            stringValue = value ? "on" : "off";
-        }
-        const nextValues: Record<string, string> = {
-            on: "off",
-            off: "on",
-            onUnlessPressed: "offUnlessPressed",
-            offUnlessPressed: "onUnlessPressed",
-        };
-        const nextValue = nextValues[stringValue] ?? "on";
-        await config.update("enabled", nextValue, vscode.ConfigurationTarget.Global);
-    };
-}
-
 // Opens the virtual file that will show the syntax tree
 //
 // The contents of the file come from the `TextDocumentContentProvider`
diff --git a/src/tools/rust-analyzer/editors/code/src/main.ts b/src/tools/rust-analyzer/editors/code/src/main.ts
index e9b62e0cc257..41bde4195e07 100644
--- a/src/tools/rust-analyzer/editors/code/src/main.ts
+++ b/src/tools/rust-analyzer/editors/code/src/main.ts
@@ -180,7 +180,6 @@ async function initCommonContext(context: vscode.ExtensionContext, ctx: Ctx) {
 
     ctx.registerCommand("ssr", commands.ssr);
     ctx.registerCommand("serverVersion", commands.serverVersion);
-    ctx.registerCommand("toggleInlayHints", commands.toggleInlayHints);
 
     // Internal commands which are invoked by the server.
     ctx.registerCommand("runSingle", commands.runSingle);
diff --git a/src/tools/rust-analyzer/lib/la-arena/src/lib.rs b/src/tools/rust-analyzer/lib/la-arena/src/lib.rs
index 50e8d06b6604..ccaaf3991769 100644
--- a/src/tools/rust-analyzer/lib/la-arena/src/lib.rs
+++ b/src/tools/rust-analyzer/lib/la-arena/src/lib.rs
@@ -322,6 +322,43 @@ impl<T> Arena<T> {
             .map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value))
     }
 
+    /// Returns an iterator over the arena’s values.
+    ///
+    /// ```
+    /// let mut arena = la_arena::Arena::new();
+    /// let idx1 = arena.alloc(20);
+    /// let idx2 = arena.alloc(40);
+    /// let idx3 = arena.alloc(60);
+    ///
+    /// let mut iterator = arena.values();
+    /// assert_eq!(iterator.next(), Some(&20));
+    /// assert_eq!(iterator.next(), Some(&40));
+    /// assert_eq!(iterator.next(), Some(&60));
+    /// ```
+    pub fn values(&mut self) -> impl Iterator<Item = &T> + ExactSizeIterator + DoubleEndedIterator {
+        self.data.iter()
+    }
+
+    /// Returns an iterator over the arena’s mutable values.
+    ///
+    /// ```
+    /// let mut arena = la_arena::Arena::new();
+    /// let idx1 = arena.alloc(20);
+    ///
+    /// assert_eq!(arena[idx1], 20);
+    ///
+    /// let mut iterator = arena.values_mut();
+    /// *iterator.next().unwrap() = 10;
+    /// drop(iterator);
+    ///
+    /// assert_eq!(arena[idx1], 10);
+    /// ```
+    pub fn values_mut(
+        &mut self,
+    ) -> impl Iterator<Item = &mut T> + ExactSizeIterator + DoubleEndedIterator {
+        self.data.iter_mut()
+    }
+
     /// Reallocates the arena to make it take up as little space as possible.
     pub fn shrink_to_fit(&mut self) {
         self.data.shrink_to_fit();
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index 3c982b261271..80bb3b5d6a8d 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/src/tools/rustc-workspace-hack/Cargo.toml
@@ -77,9 +77,6 @@ clap = { version = "3.1.1", features = ["derive", "clap_derive"]}
 curl-sys = { version = "0.4.13", features = ["http2", "libnghttp2-sys"], optional = true }
 # Ensure default features of libz-sys, which are disabled in some scenarios.
 libz-sys = { version = "1.1.2" }
-# The only user of memchr's deprecated `use_std` feature is `combine`, so this can be
-# removed if/when https://github.com/Marwes/combine/pull/348 is merged and released.
-memchr = { version = "2.5", features = ["std", "use_std"] }
 # Ensure default features of regex, which are disabled in some scenarios.
 regex = { version = "1.5.6" }
 serde_json = { version = "1.0.31", features = ["raw_value", "unbounded_depth"] }
diff --git a/src/tools/rustfmt/src/patterns.rs b/src/tools/rustfmt/src/patterns.rs
index 9b74b35f3141..e2fe92b28f23 100644
--- a/src/tools/rustfmt/src/patterns.rs
+++ b/src/tools/rustfmt/src/patterns.rs
@@ -1,4 +1,6 @@
-use rustc_ast::ast::{self, BindingMode, Pat, PatField, PatKind, RangeEnd, RangeSyntax};
+use rustc_ast::ast::{
+    self, BindingAnnotation, ByRef, Pat, PatField, PatKind, RangeEnd, RangeSyntax,
+};
 use rustc_ast::ptr;
 use rustc_span::{BytePos, Span};
 
@@ -99,10 +101,10 @@ impl Rewrite for Pat {
                 write_list(&items, &fmt)
             }
             PatKind::Box(ref pat) => rewrite_unary_prefix(context, "box ", &**pat, shape),
-            PatKind::Ident(binding_mode, ident, ref sub_pat) => {
-                let (prefix, mutability) = match binding_mode {
-                    BindingMode::ByRef(mutability) => ("ref", mutability),
-                    BindingMode::ByValue(mutability) => ("", mutability),
+            PatKind::Ident(BindingAnnotation(by_ref, mutability), ident, ref sub_pat) => {
+                let prefix = match by_ref {
+                    ByRef::Yes => "ref",
+                    ByRef::No => "",
                 };
                 let mut_infix = format_mutability(mutability).trim();
                 let id_str = rewrite_ident(context, ident);
diff --git a/src/tools/rustfmt/tests/source/issue_4257.rs b/src/tools/rustfmt/tests/source/issue_4257.rs
index 2b887fadb621..9482512efca0 100644
--- a/src/tools/rustfmt/tests/source/issue_4257.rs
+++ b/src/tools/rustfmt/tests/source/issue_4257.rs
@@ -1,6 +1,3 @@
-#![feature(generic_associated_types)]
-#![allow(incomplete_features)]
-
 trait Trait<T> {
     type Type<'a> where T: 'a;
     fn foo(x: &T) -> Self::Type<'_>;
diff --git a/src/tools/rustfmt/tests/source/issue_4911.rs b/src/tools/rustfmt/tests/source/issue_4911.rs
index 21ef6c6c491a..c254db7b509c 100644
--- a/src/tools/rustfmt/tests/source/issue_4911.rs
+++ b/src/tools/rustfmt/tests/source/issue_4911.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(min_type_alias_impl_trait)]
 
 impl SomeTrait for SomeType {
diff --git a/src/tools/rustfmt/tests/source/issue_4943.rs b/src/tools/rustfmt/tests/source/issue_4943.rs
index 0793b7b4fe1c..307d9a4a1aba 100644
--- a/src/tools/rustfmt/tests/source/issue_4943.rs
+++ b/src/tools/rustfmt/tests/source/issue_4943.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 impl SomeStruct {
     fn process<T>(v: T) -> <Self as GAT>::R<T>
     where Self: GAT<R<T> = T>
diff --git a/src/tools/rustfmt/tests/target/issue_4257.rs b/src/tools/rustfmt/tests/target/issue_4257.rs
index 1ebaaf2b6001..309a66c8dc3c 100644
--- a/src/tools/rustfmt/tests/target/issue_4257.rs
+++ b/src/tools/rustfmt/tests/target/issue_4257.rs
@@ -1,6 +1,3 @@
-#![feature(generic_associated_types)]
-#![allow(incomplete_features)]
-
 trait Trait<T> {
     type Type<'a>
     where
diff --git a/src/tools/rustfmt/tests/target/issue_4911.rs b/src/tools/rustfmt/tests/target/issue_4911.rs
index 890a62267ce6..0f64aa7f766f 100644
--- a/src/tools/rustfmt/tests/target/issue_4911.rs
+++ b/src/tools/rustfmt/tests/target/issue_4911.rs
@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![feature(min_type_alias_impl_trait)]
 
 impl SomeTrait for SomeType {
diff --git a/src/tools/rustfmt/tests/target/issue_4943.rs b/src/tools/rustfmt/tests/target/issue_4943.rs
index 318f7ebed6e0..bc8f1a366da2 100644
--- a/src/tools/rustfmt/tests/target/issue_4943.rs
+++ b/src/tools/rustfmt/tests/target/issue_4943.rs
@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 impl SomeStruct {
     fn process<T>(v: T) -> <Self as GAT>::R<T>
     where
diff --git a/src/tools/tidy/src/bins.rs b/src/tools/tidy/src/bins.rs
index 30903f56d93b..b898f20a5d01 100644
--- a/src/tools/tidy/src/bins.rs
+++ b/src/tools/tidy/src/bins.rs
@@ -21,6 +21,7 @@ mod os_impl {
 
 #[cfg(unix)]
 mod os_impl {
+    use crate::walk::{filter_dirs, walk_no_read};
     use std::fs;
     use std::os::unix::prelude::*;
     use std::path::Path;
@@ -100,10 +101,10 @@ mod os_impl {
 
         const ALLOWED: &[&str] = &["configure", "x"];
 
-        crate::walk_no_read(
+        walk_no_read(
             path,
             &mut |path| {
-                crate::filter_dirs(path)
+                filter_dirs(path)
                     || path.ends_with("src/etc")
                     // This is a list of directories that we almost certainly
                     // don't need to walk. A future PR will likely want to
diff --git a/src/tools/tidy/src/debug_artifacts.rs b/src/tools/tidy/src/debug_artifacts.rs
index ab87230f888c..9880a32ad0c2 100644
--- a/src/tools/tidy/src/debug_artifacts.rs
+++ b/src/tools/tidy/src/debug_artifacts.rs
@@ -1,5 +1,6 @@
 //! Tidy check to prevent creation of unnecessary debug artifacts while running tests.
 
+use crate::walk::{filter_dirs, walk};
 use std::path::{Path, PathBuf};
 
 const GRAPHVIZ_POSTFLOW_MSG: &str = "`borrowck_graphviz_postflow` attribute in test";
@@ -7,7 +8,7 @@ const GRAPHVIZ_POSTFLOW_MSG: &str = "`borrowck_graphviz_postflow` attribute in t
 pub fn check(path: &Path, bad: &mut bool) {
     let test_dir: PathBuf = path.join("test");
 
-    super::walk(&test_dir, &mut super::filter_dirs, &mut |entry, contents| {
+    walk(&test_dir, &mut filter_dirs, &mut |entry, contents| {
         let filename = entry.path();
         let is_rust = filename.extension().map_or(false, |ext| ext == "rs");
         if !is_rust {
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 2fe17e979c87..9aab66b1d212 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -20,6 +20,7 @@ const LICENSES: &[&str] = &[
     "Unlicense OR MIT",
     "0BSD OR MIT OR Apache-2.0", // adler license
     "Zlib OR Apache-2.0 OR MIT", // tinyvec
+    "MIT OR Apache-2.0 OR Zlib", // tinyvec_macros
     "MIT OR Zlib OR Apache-2.0", // miniz_oxide
 ];
 
@@ -91,9 +92,6 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "autocfg",
     "bitflags",
     "block-buffer",
-    "block-padding",
-    "byte-tools",
-    "byteorder",
     "cc",
     "cfg-if",
     "chalk-derive",
@@ -118,7 +116,6 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "ena",
     "env_logger",
     "expect-test",
-    "fake-simd",
     "fallible-iterator", // dependency of `thorin`
     "filetime",
     "fixedbitset",
@@ -162,7 +159,6 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "object",
     "odht",
     "once_cell",
-    "opaque-debug",
     "parking_lot",
     "parking_lot_core",
     "pathdiff",
@@ -223,6 +219,8 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "time",
     "tinystr",
     "tinyvec",
+    "tinyvec_macros",
+    "thin-vec",
     "tracing",
     "tracing-attributes",
     "tracing-core",
diff --git a/src/tools/tidy/src/edition.rs b/src/tools/tidy/src/edition.rs
index b0abee459869..8a7c4460dc7e 100644
--- a/src/tools/tidy/src/edition.rs
+++ b/src/tools/tidy/src/edition.rs
@@ -1,5 +1,6 @@
 //! Tidy check to ensure that crate `edition` is '2018' or '2021'.
 
+use crate::walk::{filter_dirs, walk};
 use std::path::Path;
 
 fn is_edition_2021(mut line: &str) -> bool {
@@ -8,9 +9,9 @@ fn is_edition_2021(mut line: &str) -> bool {
 }
 
 pub fn check(path: &Path, bad: &mut bool) {
-    super::walk(
+    walk(
         path,
-        &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
+        &mut |path| filter_dirs(path) || path.ends_with("src/test"),
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap();
diff --git a/src/tools/tidy/src/error_codes_check.rs b/src/tools/tidy/src/error_codes_check.rs
index 0a226443e01c..610e322e1296 100644
--- a/src/tools/tidy/src/error_codes_check.rs
+++ b/src/tools/tidy/src/error_codes_check.rs
@@ -1,6 +1,7 @@
 //! Checks that all error codes have at least one test to prevent having error
 //! codes that are silently not thrown by the compiler anymore.
 
+use crate::walk::{filter_dirs, walk};
 use std::collections::{HashMap, HashSet};
 use std::ffi::OsStr;
 use std::fs::read_to_string;
@@ -217,7 +218,7 @@ pub fn check(paths: &[&Path], bad: &mut bool) {
     println!("Checking which error codes lack tests...");
 
     for path in paths {
-        super::walk(path, &mut super::filter_dirs, &mut |entry, contents| {
+        walk(path, &mut filter_dirs, &mut |entry, contents| {
             let file_name = entry.file_name();
             let entry_path = entry.path();
 
diff --git a/src/tools/tidy/src/errors.rs b/src/tools/tidy/src/errors.rs
index dbcc9341a084..fe5fd72b91a4 100644
--- a/src/tools/tidy/src/errors.rs
+++ b/src/tools/tidy/src/errors.rs
@@ -3,14 +3,15 @@
 //! This ensures that error codes are used at most once and also prints out some
 //! statistics about the error codes.
 
+use crate::walk::{filter_dirs, walk};
 use std::collections::HashMap;
 use std::path::Path;
 
 pub fn check(path: &Path, bad: &mut bool) {
     let mut map: HashMap<_, Vec<_>> = HashMap::new();
-    super::walk(
+    walk(
         path,
-        &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
+        &mut |path| filter_dirs(path) || path.ends_with("src/test"),
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap().to_string_lossy();
diff --git a/src/tools/tidy/src/features.rs b/src/tools/tidy/src/features.rs
index de292d3305db..28a0700a64bf 100644
--- a/src/tools/tidy/src/features.rs
+++ b/src/tools/tidy/src/features.rs
@@ -9,6 +9,7 @@
 //! * All unstable lang features have tests to ensure they are actually unstable.
 //! * Language features in a group are sorted by feature name.
 
+use crate::walk::{filter_dirs, walk, walk_many};
 use std::collections::HashMap;
 use std::fmt;
 use std::fs;
@@ -92,14 +93,14 @@ pub fn check(
     let lib_features = get_and_check_lib_features(lib_path, bad, &features);
     assert!(!lib_features.is_empty());
 
-    super::walk_many(
+    walk_many(
         &[
             &src_path.join("test/ui"),
             &src_path.join("test/ui-fulldeps"),
             &src_path.join("test/rustdoc-ui"),
             &src_path.join("test/rustdoc"),
         ],
-        &mut |path| super::filter_dirs(path),
+        &mut filter_dirs,
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap().to_string_lossy();
@@ -199,8 +200,7 @@ pub fn check(
         if channel != "nightly" && since == Version::CurrentPlaceholder {
             tidy_error!(
                 bad,
-                "The placeholder use of {kind} feature `{feature_name}` is not allowed on the {} channel",
-                version::VERSION_PLACEHOLDER
+                "The placeholder use of {kind} feature `{feature_name}` is not allowed on the {channel} channel",
             );
         }
     }
@@ -467,9 +467,9 @@ fn map_lib_features(
     base_src_path: &Path,
     mf: &mut dyn FnMut(Result<(&str, Feature), &str>, &Path, usize),
 ) {
-    super::walk(
+    walk(
         base_src_path,
-        &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
+        &mut |path| filter_dirs(path) || path.ends_with("src/test"),
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap().to_string_lossy();
diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index 12d3bdcd76f8..e82cca402e2d 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -3,8 +3,6 @@
 //! This library contains the tidy lints and exposes it
 //! to be used by tools.
 
-use walk::{filter_dirs, walk, walk_many, walk_no_read};
-
 /// A helper macro to `unwrap` a result except also print out details like:
 ///
 /// * The expression that failed
diff --git a/src/tools/tidy/src/pal.rs b/src/tools/tidy/src/pal.rs
index 4d86fe8be4e0..f4592fdcff9d 100644
--- a/src/tools/tidy/src/pal.rs
+++ b/src/tools/tidy/src/pal.rs
@@ -30,6 +30,7 @@
 //! platform-specific cfgs are allowed. Not sure yet how to deal with
 //! this in the long term.
 
+use crate::walk::{filter_dirs, walk};
 use std::iter::Iterator;
 use std::path::Path;
 
@@ -67,7 +68,7 @@ pub fn check(path: &Path, bad: &mut bool) {
     // Sanity check that the complex parsing here works.
     let mut saw_target_arch = false;
     let mut saw_cfg_bang = false;
-    super::walk(path, &mut super::filter_dirs, &mut |entry, contents| {
+    walk(path, &mut filter_dirs, &mut |entry, contents| {
         let file = entry.path();
         let filestr = file.to_string_lossy().replace("\\", "/");
         if !filestr.ends_with(".rs") {
diff --git a/src/tools/tidy/src/style.rs b/src/tools/tidy/src/style.rs
index dee58ff2fb51..541380cebde8 100644
--- a/src/tools/tidy/src/style.rs
+++ b/src/tools/tidy/src/style.rs
@@ -16,6 +16,7 @@
 //! A number of these checks can be opted-out of with various directives of the form:
 //! `// ignore-tidy-CHECK-NAME`.
 
+use crate::walk::{filter_dirs, walk};
 use regex::Regex;
 use std::path::Path;
 
@@ -218,13 +219,13 @@ fn is_unexplained_ignore(extension: &str, line: &str) -> bool {
 
 pub fn check(path: &Path, bad: &mut bool) {
     fn skip(path: &Path) -> bool {
-        super::filter_dirs(path) || skip_markdown_path(path)
+        filter_dirs(path) || skip_markdown_path(path)
     }
     let problematic_consts_strings: Vec<String> = (PROBLEMATIC_CONSTS.iter().map(u32::to_string))
         .chain(PROBLEMATIC_CONSTS.iter().map(|v| format!("{:x}", v)))
         .chain(PROBLEMATIC_CONSTS.iter().map(|v| format!("{:X}", v)))
         .collect();
-    super::walk(path, &mut skip, &mut |entry, contents| {
+    walk(path, &mut skip, &mut |entry, contents| {
         let file = entry.path();
         let filename = file.file_name().unwrap().to_string_lossy();
         let extensions = [".rs", ".py", ".js", ".sh", ".c", ".cpp", ".h", ".md", ".css", ".ftl"];
diff --git a/src/tools/tidy/src/target_specific_tests.rs b/src/tools/tidy/src/target_specific_tests.rs
index 723684bfa4cd..8ba25705666a 100644
--- a/src/tools/tidy/src/target_specific_tests.rs
+++ b/src/tools/tidy/src/target_specific_tests.rs
@@ -36,7 +36,7 @@ struct RevisionInfo<'a> {
 
 pub fn check(path: &Path, bad: &mut bool) {
     let tests = path.join("test");
-    super::walk(
+    crate::walk::walk(
         &tests,
         &mut |path| path.extension().map(|p| p == "rs") == Some(false),
         &mut |entry, content| {
diff --git a/src/tools/tidy/src/ui_tests.rs b/src/tools/tidy/src/ui_tests.rs
index 8ec5c3324933..969d5fec60f3 100644
--- a/src/tools/tidy/src/ui_tests.rs
+++ b/src/tools/tidy/src/ui_tests.rs
@@ -47,7 +47,7 @@ fn check_entries(path: &Path, bad: &mut bool) {
 pub fn check(path: &Path, bad: &mut bool) {
     check_entries(&path, bad);
     for path in &[&path.join("test/ui"), &path.join("test/ui-fulldeps")] {
-        super::walk_no_read(path, &mut |_| false, &mut |entry| {
+        crate::walk::walk_no_read(path, &mut |_| false, &mut |entry| {
             let file_path = entry.path();
             if let Some(ext) = file_path.extension() {
                 if ext == "stderr" || ext == "stdout" {
diff --git a/src/tools/tidy/src/unit_tests.rs b/src/tools/tidy/src/unit_tests.rs
index f675b78651ef..2c23b6ebc75e 100644
--- a/src/tools/tidy/src/unit_tests.rs
+++ b/src/tools/tidy/src/unit_tests.rs
@@ -7,6 +7,7 @@
 //! named `tests.rs` or `benches.rs`, or directories named `tests` or `benches` unconfigured
 //! during normal build.
 
+use crate::walk::{filter_dirs, walk};
 use std::path::Path;
 
 pub fn check(root_path: &Path, bad: &mut bool) {
@@ -20,7 +21,7 @@ pub fn check(root_path: &Path, bad: &mut bool) {
     let mut skip = |path: &Path| {
         let file_name = path.file_name().unwrap_or_default();
         if path.is_dir() {
-            super::filter_dirs(path)
+            filter_dirs(path)
                 || path.ends_with("src/test")
                 || path.ends_with("src/doc")
                 || (file_name == "tests" || file_name == "benches") && !is_core(path)
@@ -34,7 +35,7 @@ pub fn check(root_path: &Path, bad: &mut bool) {
         }
     };
 
-    super::walk(root_path, &mut skip, &mut |entry, contents| {
+    walk(root_path, &mut skip, &mut |entry, contents| {
         let path = entry.path();
         let is_core = path.starts_with(core);
         for (i, line) in contents.lines().enumerate() {
diff --git a/src/tools/tidy/src/walk.rs b/src/tools/tidy/src/walk.rs
index 6dca55dfa9fa..4cfb70fa31c4 100644
--- a/src/tools/tidy/src/walk.rs
+++ b/src/tools/tidy/src/walk.rs
@@ -21,8 +21,15 @@ pub fn filter_dirs(path: &Path) -> bool {
         "src/tools/rust-installer",
         "src/tools/rustfmt",
         "src/doc/book",
+        "src/doc/edition-guide",
+        "src/doc/embedded-book",
+        "src/doc/nomicon",
+        "src/doc/rust-by-example",
+        "src/doc/rustc-dev-guide",
+        "src/doc/reference",
         // Filter RLS output directories
         "target/rls",
+        "src/bootstrap/target",
     ];
     skip.iter().any(|p| path.ends_with(p))
 }
diff --git a/src/tools/unicode-table-generator/src/range_search.rs b/src/tools/unicode-table-generator/src/range_search.rs
index 39b47ce703f3..3a5b869f72f7 100644
--- a/src/tools/unicode-table-generator/src/range_search.rs
+++ b/src/tools/unicode-table-generator/src/range_search.rs
@@ -1,5 +1,6 @@
+#[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]
 #[inline(always)]
-fn bitset_search<
+const fn bitset_search<
     const N: usize,
     const CHUNK_SIZE: usize,
     const N1: usize,
@@ -15,14 +16,18 @@ fn bitset_search<
     let bucket_idx = (needle / 64) as usize;
     let chunk_map_idx = bucket_idx / CHUNK_SIZE;
     let chunk_piece = bucket_idx % CHUNK_SIZE;
-    let chunk_idx = if let Some(&v) = chunk_idx_map.get(chunk_map_idx) {
-        v
+    // FIXME: const-hack: Revert to `slice::get` after `const_slice_index`
+    // feature stabilizes.
+    let chunk_idx = if chunk_map_idx < chunk_idx_map.len() {
+        chunk_idx_map[chunk_map_idx]
     } else {
         return false;
     };
     let idx = bitset_chunk_idx[chunk_idx as usize][chunk_piece] as usize;
-    let word = if let Some(word) = bitset_canonical.get(idx) {
-        *word
+    // FIXME: const-hack: Revert to `slice::get` after `const_slice_index`
+    // feature stabilizes.
+    let word = if idx < bitset_canonical.len() {
+        bitset_canonical[idx]
     } else {
         let (real_idx, mapping) = bitset_canonicalized[idx - bitset_canonical.len()];
         let mut word = bitset_canonical[real_idx as usize];
diff --git a/src/tools/unicode-table-generator/src/raw_emitter.rs b/src/tools/unicode-table-generator/src/raw_emitter.rs
index 13eed7b10997..890ff986c2be 100644
--- a/src/tools/unicode-table-generator/src/raw_emitter.rs
+++ b/src/tools/unicode-table-generator/src/raw_emitter.rs
@@ -76,7 +76,7 @@ impl RawEmitter {
 
         writeln!(
             &mut self.file,
-            "static BITSET_CANONICAL: [u64; {}] = [{}];",
+            "const BITSET_CANONICAL: &'static [u64; {}] = &[{}];",
             canonicalized.canonical_words.len(),
             fmt_list(canonicalized.canonical_words.iter().map(|v| Bits(*v))),
         )
@@ -84,7 +84,7 @@ impl RawEmitter {
         self.bytes_used += 8 * canonicalized.canonical_words.len();
         writeln!(
             &mut self.file,
-            "static BITSET_MAPPING: [(u8, u8); {}] = [{}];",
+            "const BITSET_MAPPING: &'static [(u8, u8); {}] = &[{}];",
             canonicalized.canonicalized_words.len(),
             fmt_list(&canonicalized.canonicalized_words),
         )
@@ -96,7 +96,12 @@ impl RawEmitter {
 
         self.blank_line();
 
-        writeln!(&mut self.file, "pub fn lookup(c: char) -> bool {{").unwrap();
+        writeln!(
+            &mut self.file,
+            r#"#[rustc_const_unstable(feature = "const_unicode_case_lookup", issue = "101400")]"#
+        )
+        .unwrap();
+        writeln!(&mut self.file, "pub const fn lookup(c: char) -> bool {{").unwrap();
         writeln!(&mut self.file, "    super::bitset_search(",).unwrap();
         writeln!(&mut self.file, "        c as u32,").unwrap();
         writeln!(&mut self.file, "        &BITSET_CHUNKS_MAP,").unwrap();
@@ -130,7 +135,7 @@ impl RawEmitter {
 
         writeln!(
             &mut self.file,
-            "static BITSET_CHUNKS_MAP: [u8; {}] = [{}];",
+            "const BITSET_CHUNKS_MAP: &'static [u8; {}] = &[{}];",
             chunk_indices.len(),
             fmt_list(&chunk_indices),
         )
@@ -138,7 +143,7 @@ impl RawEmitter {
         self.bytes_used += chunk_indices.len();
         writeln!(
             &mut self.file,
-            "static BITSET_INDEX_CHUNKS: [[u8; {}]; {}] = [{}];",
+            "const BITSET_INDEX_CHUNKS: &'static [[u8; {}]; {}] = &[{}];",
             chunk_length,
             chunks.len(),
             fmt_list(chunks.iter()),
diff --git a/src/version b/src/version
index 902c74186fb6..b6148bc0a759 100644
--- a/src/version
+++ b/src/version
@@ -1 +1 @@
-1.65.0
+1.66.0
diff --git a/triagebot.toml b/triagebot.toml
index 8a90bc0e3c14..d358e59c2452 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -11,6 +11,7 @@ allow-unauthenticated = [
     "S-*",
     "T-*",
     "WG-*",
+    "const-hack",
     "needs-fcp",
     "relnotes",
     "requires-nightly",
@@ -129,8 +130,8 @@ trigger_files = [
 
     # Internal tooling
     "src/etc/htmldocck.py",
-    "src/etc/check_missing_items.py",
     "src/tools/jsondocck",
+    "src/tools/jsondoclint",
     "src/tools/rustdoc-gui",
     "src/tools/rustdoc-js",
     "src/tools/rustdoc-themes",
@@ -141,11 +142,11 @@ exclude_labels = [
 
 [autolabel."A-rustdoc-json"]
 trigger_files = [
-    "src/etc/check_missing_items.py",
     "src/librustdoc/json/",
     "src/rustdoc-json-types",
     "src/test/rustdoc-json",
     "src/tools/jsondocck",
+    "src/tools/jsondoclint",
 ]
 
 [autolabel."T-compiler"]
@@ -195,6 +196,13 @@ trigger_files = [
     "compiler/rustc_macros/src/diagnostics"
 ]
 
+[autolabel."A-query-system"]
+trigger_files = [
+    "compiler/rustc_query_system",
+    "compiler/rustc_query_impl",
+    "compiler/rustc_macros/src/query.rs"
+]
+
 [notify-zulip."I-prioritize"]
 zulip_stream = 245100 # #t-compiler/wg-prioritization/alerts
 topic = "#{number} {title}"
@@ -309,9 +317,6 @@ Examples of `T-libs-api` changes:
 * Changing observable runtime behavior of library APIs
 """
 
-[mentions."library/proc_macro/src/bridge"]
-cc = ["@rust-lang/wg-rls-2"]
-
 [mentions."src/librustdoc/clean/types.rs"]
 cc = ["@camelid"]
 
@@ -341,6 +346,7 @@ cc = [
     "@CraftSpider",
     "@aDotInTheVoid",
     "@Enselic",
+    "@obi1kenobi",
 ]
 
 [mentions."src/tools/cargo"]
@@ -350,7 +356,7 @@ cc = ["@ehuss"]
 cc = ["@rust-lang/clippy"]
 
 [mentions."src/tools/miri"]
-message = "The Miri submodule was changed"
+message = "The Miri subtree was changed"
 cc = ["@rust-lang/miri"]
 
 [mentions."src/tools/rustfmt"]